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MATNiSD  M.  METCMJ, 


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HISTORY  OF  INFUSORIA^ 


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THE  DESMIDIACE^  AND  DIATOMACE^, 


BRITISH  AND   FOREIGN. 


BY 

ANDREW  PRITCHARD,  Esq.,  M.R.I., 

AUTHOR    OF   TUB    'MICROSCOPIC    CABINET,'    ETC. 


FOURTH  EDITION. 

ENLARGED  AND  REVISED  BY 
J.  T.  AELIDOE,  M.B.,  B.A.  Lond.  ;  W.  AECHEE,  Esq.  ; 
J.  EALES,  M.E.C.S.L. ;  W.  C.  WILLIAMSON,  Esq.,  F.E.S. 
AND  THE  AUTHOE. 


ILLUSTRATED  BY  FORTY  PLATES. 


LONDON: 
WHITTAKER   AND   CO.,  AVE   MARIA   LANE. 

1861. 

[  The  rig  Jit  of  translation  is  reserved.'] 


PRINTED    BY   TAYLOR   AND    FRANCIS, 
RED  LION  COURT,  FLEET  STREET. 


— v^, 

{uu    LIBRARY  j. J 


PREFACE. 


Special  interest  has  always  been  taken  by  man  in  the  structure  and 
development  of  the  minute  forms  of  life,  whether  animal  or  vegetable  : 
in  this  volume  I  propose  to  lay  before  the  reader  a  resume  of  the 
present  state  of  our  knowledge  of  the  multitude  of  K^dng  beings  called 
Infusoria.  This  term_,  as  employed  by  Professor  Ehrenberg  of 
Berlin^  includes  a  wide  range  both  of  animal  and  vegetable  life; 
while  it  is  now  restricted  by  other  naturalists  to  the  Protozoa^  and, 
in  the  works  recently  commenced  by  Dr.  Stein  and  MM.  Claparede 
and  Lachmann,  to  the  ciliated  members  of  that  group. 

The  former  editions  of  this  work  having  included  a  Histoiy  of  the 
Bacillaria,  Phytozoa,  Protozoa  (under  the  name  Polygastrica),  and  of 
the  Rotatoria,  it  is  incumbent  on  me  to  retain  these  groups,  though 
the  researches  of  late  years  have  so  extended  our  acquaintance  with 
them  that  much  difficulty  has  been  felt  in  the  attempt  to  comprise 
the  whole  in  a  single  volume,  so  necessary  for  a  practical  manual. 

The  successful  investigation  of  this  department  of  Natural  History 
arose  mainly  from  the  improvement  of  the  microscope  consequent 
upon  the  discoveries  of  "Test  Objects'^  and  "penetrating  power/^ 
the  latter  depending  upon  "  angular  aperture/^ — discoveries  which 
my  colleague  the  late  Dr.  Goring  and  myself  had  the  pleasure  of 
presenting  to  the  public.  The  microscope,  having  become  thereby  a 
reliable  instrument,  has  revealed  to  us  the  true  forms  and  structure  of 
these  beings. 

Part  I.  is  devoted  to  a  General  History  of  the  several  more  or  less 
natural  groups  of  Infusoria:  it  contains  also  the  observations  and 
opinions  of  British  and  Continental  naturalists  on  their  nature, 
structure,  functions,  and  classification.  The  foreign  writings  on 
these  subjects  are  so  voluminous  that  even  an  abstract  of  them  has 
increased  this  part  of  the  work  much  beyond  what  it  occupied  in 


IV  TREFACS. 

former  editions_,  wliile  the  introduction  of  the  Tables  from  Part  II. 
has  further  extended  it ;  but,  as  I  have  been  anxious  to  give  an 
impartial  account  of  the  researches  on  this  subject,  a  briefer  summary- 
might  have  impaired  its  usefulness  and  value.  To  Dr.  Arlidge  is 
due  the  rearrangement  and  preparation  of  this  part. 

Part  II.  contains  descriptions  of  the  Families,  Genera,  and  Species 
of  the  groups  whose  general  history  forms  the  subject  of  the  preceding 
part  of  this  volume.  The  systematic  arrangement  of  Ehrenberg  has 
been  retained  for  the  Phytozoa,  Protozoa,  and  Rotatoria,  the  new 
genera  and  species  of  other  naturalists  being  collated  and  engrafted 
thereon.  The  descriptions  of  those  curious  and  higlily-organized 
creatures  the  Rotatoria  have  been  extended  and  revised  by  Professor 
Williamson  of  Manchester,  whose  original  researches  and  observa- 
tions on  this  group  are  greatly  appreciated,  both  in  this  country  and 
abroad. 

In  consequence  of  the  long  illness  of  Mr.  Ralfs,  who  had  under- 
taken the  re\dsion  of  the  Bacillaria,  the  publication  of  this  edition  has 
been  delayed,  and  that  group  has  been  printed  last — a  deviation  from 
the  original  design  which  it  is  hoped  will  not  inconvenience  the 
reader,  while  it  has  allowed  opportunity  for  the  insertion  of  the  latest 
researches.  Owing  to  the  circumstance  stated  above,  the  revision  of 
the  Systematic  History  of  the  Family  or  Subgroup  Desmidiacese  has 
been  kindly  carried  out  by  Mr.  William  Archer  of  Dublin,  who  has 
added  some  original  views,  expressing  by  symbols  the  characters  of 
certain  genera ;  moreover,  M.  de  Brebisson  of  Falaise  has  given  this 
edition  the  benefit  of  his  valuable  co-operation,  by  furnishing  descrip- 
tions of  the  newly- discovered  foreign  species. 

The  elegance  and  variety  of  the  forms,  the  beauty  and  elaborate 
sculpturing  of  the  silicious  shells  of  the  Diatomacese,  and  the  general 
interest  now  taken  in  their  study,  rendered  it  desirable  to  bring  together 
in  this  volume  ail  the  known  genera  and  species,  British  and  foreign. 
This  I  have  been  able  to  effect  by  the  research  of  Mr.  Ralfs,  whose 
name  is  so  intimately  identified  with  the  knowledge  of  these  organisms, 
and  whose  present  arrangement  of  their  families  and  genera  will  no 
doubt  tend  to  facilitate  our  better  acquaintance  with  them.  Owing  to 
the  great  dimensions  which  this  treatise  has  acquired,  and  the  limited 
space  consequently  at  command,  I  was  under  the  necessity  of  con- 
densing the  manuscript  of  Mr.  Ralfs,  and  of  introducing  abbrevi- 


PREFACE.  V 

ations.  Still  1  havC;,  in  accordance  with  my  original  design,  given 
every  known  specific  name,  wlietlier  synonym  or  variety,  whereby 
observers  may  avoid  confusion  in  the  nomenclature  by  not  employing 
the  same  names  for  newly-discovered  forms.  The  references  now 
introduced  are  to  works  published  subsequently  to  the  early  editions 
of  this  book :  for  their  verification  I  am  indebted  to  Mr.  Kitton 
of  Norwich. 

Twenty-one  new  Plates  have  been  added  to  this  edition,  of  which 
six  are  engraved  by  Mr.  Tuffen  West.  In  the  case  of  the  Diatoms, 
all  the  new  figures  are  drawn  to  one  scale,  representing  a  magnifying 
power  of  300  diameters;  many  of  them  likewise  are  drawn  from 
specimens,  whilst  others  are  engraved  from  original  drawings  kindly 
lent  by  Mr.  George  Norman  of  Hull,  Mr.  Eoper  of  Clapton,  and 
Mr.  Brightwell  of  Normch. 

It  now  becomes  my  pleasing  duty  to  acknowledge  the  kind  assist- 
ance received  from  the  late  Professors  Gregory  of  Edinburgh  and 
BxiiLEY  of  New  York;  also  to  tender  to  Drs.  Donivin,  Greville, 
Francis,  Wallich,  Strethill  Wright,  and  Mr.  Gosse,  along  with 
the  gentlemen  before  named,  my  best  thanks  for  their  aid  and  advice 
during  the  progress  of  this  laborious  undertaking. 

In  conclusion,  should  the  object  proposed  in  the  reissue  of  this 
work  be  attained,  viz.  to  produce  in  a  single  volume  a  compendium 
of  the  present  state  of  knowledge,  calculated  to  promote  and  facilitate 
the  study  of  the  veiy  interesting  branch  of  Natural  History  which 
forms  its  subject,  and  which  has  occupied  much  of  my  leisure  time 
for  more  than  forty  years,  I  shall  be  fully  content. 

ANDREW  PRITCHARD. 

Canonbury,  London,  N.  .•■-^ To "*•**>. 

November  15,  1860.  /Cm^ ^^A^    ^ 


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CONTENTS. 


Preface Page  iii 

List  of  works  quoted  and  abbreviations  used  herein ix 

PAET  I. — A  General  History  op  Infusoria,  etc. 

Bacillaria  :  Desmidiece,  their  figure,  page  1 ;  colom*,  consistence,  envelopes,  openings  in 
lorica,  4 ;  movements  and  external  cilia,  5  ;  contents  of  fronds,  6 ;  circulation  of  con- 
tents, 7;  reproduction,  11;  habitats,  distribution,  appearance  in  masses  and  vital 
endowments,  vegetable  natm-e  and  affinities,  mode  of  collection,  20. — Tediadrece,  their 
figure,  composition,  and  contents  of  cells,  24 ;  number  and  disposition  of  the  cells  in 
the  fronds,  25  ;  development  and  growth,  29 ;  systematic  position,  30. — Biatomacecs, 
their  general  and  external  characters,  31 ;  figiu'e,  32 ;  the  silicious  shell  or  lorica,  its 
divisions  and  structm'al  composition,  markings,  striae,  canalicidi,  puncta,  &c.,  37; 
contents  of  frustides,  supposed  digestive  sacs,  reproductive  vesicles,  &c.,  47;  move- 
ments, their  character  and  causes,  cilia,  circulation  of  contents,  respiration,  50; 
nutritive  functions,  supposed  stomachs,  56 ;  multiplication,  reproduction,  and  develop- 
ment, 58 ;  conjugation,  61 ;  habitats,  appearance  m  masses,  abundance,  75 ;  geogra- 
pliical  distribution,  79 ;  geological  importance  and  fossil  accumidations,  82 ;  aerolitic 
Diatomete,  85  ;  uses  of  Diatomaceous  deposits,  86 ;  of  the  nature  of  Diatome^e,  whether 
animals  or  plants,  various  hypotheses,  87;  determination  of  species  and  genera, 
varieties,  classification  of  Kiitzing,  Smith,  and  others,  96 ;  on  the  mode  of  obtaining, 
preparing,  and  preserving  specimens,  102. 

Phytozoa:  the  beings  included  imder  this  name,  their  general  character,  division  into 
groups  or  tribes,  their  figure,  coverings,  111;  cell-contents,  113;  movements,  117; 
process  of  nutrition,  119;  multiplication  and  reproduction,  fission,  macrogo'nidia^ 
microgonidia,  120;  encysting  process,  condition  of  rest,  123;  phases  of  being  and' 
alternation  of  generation,  124;  on  their  nature,  animal  and  vegetable  characters,  128; 
habitats,  occurrence  in  masses,  colour  caused  by  their  accimiulation,  129. — Families : 
Monadina,  ISO ;  Cryptomo7iadma,  14Q ;  Volvocin a,  144:;  Vibrionia,  184: ;  Astastcea  ov 
Euglencea,  188 ;  nature  of  Astasiaea,  196. 

Protozoa,  199. — Bhizopoda,  201;  movements  of  contained  particles,  210;  nucleus,  211- 
reproduction,  213;  of  the  testaceous  shells  of  Monothalamia,  218;  shells  of  Polytha- 
lamia  or  Foraminifera,  222;  dimensions  and  conditions  of  life,  227;  habitats  and 
distribution,  229 ;  of  their  cell-nature  and  characters  as  individuals  or  as  colonies  of 
animals,  232 ;  on  their  affinities,  234 ;  classification,  237.  Actinophri/ina,  243 ; 
movements,  246;  prehension  and  entrance  of  food,  247;  contractile  vesicle,  250; 
nucleus,  252 ;  encysting,  fission,  gemmation,  embryos,  253 ;  conjugation,  256 ;  loca- 
lities, affinities,  257.  Acinetina,  258 ;  origin  and  development,  261.  Gregarinida, 
262.  Psorospermia,  265.  Ciliata,  266.  Subgroup  A.  Astoma:  OpalincBa,  their 
general  characters  and  functions,  267 ;  nucleus,  self-division,  supposed  embryos,  269 ; 
habitats,  vital  endowments,  nature,  affinities,  classification,  270.  Peridinicea'  271  • 
contents,  274 ;  reproduction,  275.  Subgroup  B.  Sfomatoda :  dimensions,  277 ;  figure,' 
278 ;  consistence,  279 ;  integmnent,  markings  on  surface,  spines,  lorica,  280 ;  externai 
sheaths  or  cases,  282;  ciHa  and  ciliary  action,  285;  locomotive  and  fixed  forms 
varieties  of  locomotion,  transitory  power  of  locomotion  among  the  attached  genera,' 
288;  structure  of  pedicles,  292;  compound  special  organs  of  locomotion  and  pre- 
hension, the  peristom  and  rotary  or  ciliated  disc,  the  spirally-coiled  head  of  Spiro- 
chona,  294. — Ciliated  Protozoa,  internal  organization :  subtegumentary  layer,  chloro- 
phyll, thi'ead-cells,  297 ;  muscles,  300 ;  organs  of  digestion,  nutrition,  and  secretion, 
301;  the  polygastric  hypothesis,  303;  dental  apparatus  or  teeth,  311;  contractile 
vesicle,  312;  nucleus,  nucleolus,  326;  ovules,  334;  spermatozoids,  337;  accessory 
contents,  graniUes,  molecules,  spherical  cells,  supposed  glands,  338;  circulation  of 
contents,  339.     The  encysting  process,  .341 ;  reproduction,  fission,  gemmation,  internal 


39723 


Vlll  CONTENTS. 

ova  producing  germs  or  embryos,  impregnation,  production  of  new  beings  with  aiid 
without  metamorphosis,  transformation  into  Acinetre,  345 ;  nature  of  Ciliated  Pro- 
tozoa, their  existence  as  independent  organisms,  cell-theory  applied  to  tlunn,  368: 
conditions  of  life,  370 ;  succession  of  species,  371 ;  duration  of  life,  influence  of 
external  agents,  heat  and  cold,  373 ;  necessity  of  air,  chemical  agents,  electricity  and 
galvanism,  374;  affinities  with  other  animals,  geographical  distribution,  375 ;  classi- 
fication, 376.  Subgroups  of  Ciliated  Protozoa :  Icldliyclina,  380;  Noctihicida,  382; 
Dysteria,  387. 

EoTATORiA  or  RoTiFERA :  general  characters,  392 ;  appendages,  397 ;  the  muscular  system, 
406 ;  movements,  409 ;  the  digestiA^e  system,  410 ;  reception  of  food,  its  deglutition, 
420 ;  the  secreting  system,  422 ;  the  vascular  and  respiratory  systems,  426 ;  the 
nervous  system,  organs  of  sense,  psychical  endowments,  434;  reproductive  organs, 
441 ;  formation  of  ova,  442 ;  development  of  embryo,  445 ;  the  embryo-metamor- 
phosis, 447 ;  winter  ova,  450 ;  male  Rotatoria,  453 ;  duration  and  conditions  of  life, 
habitats  and  distribution,  463 ;  affinities  and  classification,  468 ;  Elirenberg's  classifi- 
cation, 478 ;  Dujardin  and  Ley  dig's  classifications,  480. 

Tardigrada  :  their  structure,  habitats,  and  affinities,  482. 


PAET  II. — A  Systematic  History  of  Infusoria,  with  Descriptions  op  the 
Families,  Gtenera,  and  Species. 

Group  PiiYTOzoA.  Families :  Monadina,  485 ;  Hydromorina,  503 ;  Cryptomonadina,  505 ; 
Volvocina,  514 ;  Vibrionia,  529 ;  Astasia^a  or  Euglenaea,  538 ;  Dinobryina,  547. 

Group  Protozoa — Subgroup  Ehizojyoda.  547:  Amoebsca,  548;  Arcellina,  551;  Actino- 
pliryina,  558 ;  Acinetina,  564.  —  Subgroup  Ciliata,  568.  Astoma :  Opalinsea,  569 ; 
Cyclidina,  571 ;  Peridinisea,  574.  Stomatoda :  Vorticellina,  579 ;  Ophrydina,  Vaginifera, 
598;  Enchelia,  605;  Colepina,  616:  Trachelina,  616;  Ophryoc«rcina,  630;  Aspidis- 
cina,  631 ;  Kolpodea  or  Colpodea,  631 ;  Oxylrichina,  639;  Euplotina,  645. 

Group  Rotatoria.  Families :  Ichthydina,  660 ;  CEcistina,  663 ;  Megalotrochasa,  664 ; 
Floscularia,  665  ;  Hydatineea,  677 ;  Albertina,  693 ;  Euchlanidota,  693 ;  Philodineea, 
700 ;  Brachionsea,  706. 

Group  Tardigrada,  713. 

Group  Bacillaria  :  Desmidiacete,  715  ;  Diatomacese,  756. 

Index  to  the  Illustrations  of  the  Diatomaceae,  941. 

Description  of  the  Plates,  949. 

Index  to  the  Families  and  Genera,  965. 


A 
LIST    OF    ABBREVIATIONS 


OF 


WORKS  AND  AUTHORS'  NAMES  REFERRED  TO  IN  THE 
PRESENT  EDITION. 


Abliandlimgen  der  Berliner  Academie  der  Wissenscliaften. 

Abhandlimgen  der  SenckenlDergisclien  Gesellschaft  in  Frankfiiii;  am  Main. 

Ag  CD.  or  AD.     Agardli's  Conspectus  Diatomonim. 

ANH.     Annals  and  Magazine  of  Natural  History. 

Anat.  d.  T\drbellos.  Thiere.      Siebold,  C.  Tli.  you.      Lehrbuch  der  vergleicheuden 

Anatomie  der  wdrbellosen  Tliiere.     Berlin,  1848. 
Ar.  or  Ai'n.     Professor  G.  "Walker- Arnott,  LL.D. 
ASA.  or  A  A.     Agardh's  Systema  Algarum. 
ASN.  or  Ann.  d.  SN.     Annales  des  Sciences  Naturelles,  Pans. 
B.  or  Bai.     Professor  Bailey  of  New  York. 
BAJ.     Professor  Bailev,  in  American  Journal  of  Science. 

BC.  or  BSC.     Professo\'  Bailey's  Contributions  to  Knowledge,  Smithsonian  Insti- 
tution. 

BMO.     Professor  Bailey's  Microscopic  Organisms 

Boston  Journal  of  Natural  History.     1853. 

Braun,  A.,  Prof.     Algarum  Unicellularum  Genera  nova  aut  minus  cognita.     18.55. 

Breb.     M.  de  Brebisson  of  Falaise. 

BD.  M.  de  Brebisson's  Diatomaceae  of  Cherbourg. 
Bri.     T.  Brightwell,  Esq.,  Nor\%'ich. 

Brit.  Assoc.  '  Transactions  of  the  British  Association  for  the  Advancement  of 

Science. 
British  Desmidiese.     By  John  Ralfs.     1848. 

Brit,  and  Foreign  Med."  Rev.     British  and  Foreign  Medico-Chirurgical  Review. 
Bulletin  de  L' Academie  de  St.  Petersbourg,  xiii.     1855. 
Cai*penter,  Dr.  W.  B.     The  Microscope. 
Carus.     Icones  Zootomicse.     1858. 
Cohn,  R.  S.      Professor  Cohn  on  the  Structm'e  of  Protococcus  ijhiriulis.      Ray 

Society,  1853.     London. 
Comptes  Rendus  de  1' Academie  Imperiale  des  Sciences. 
D'Orbigny,  Alcide,  Foraminiferes  Fossiles,  1846. 
Duj.  or  Du.     Dujardin,  F.,  Histoire  Naturelle  des  Zoophytes. — Infusoires.     Paris, 

1841. 
E.,  Eh.,  or  Ehr.     Professor  Ehrenberg,  Berlin. 
EA.     Professor  Ehrenberg's  Mikroscopischen  Lebens  in  Amerika. 
Edin.  New  Phil.  Jouni.     Edinburgh  New  Philosophical  Journal. 
Einzell.  Alg.     Nageli,  Prof.,  Gattunoen  einzelliger  Algen.     Zurich,  1849. 
EI.  or  Inf.     Professor  Ehrenberg's  Die  Infusionsthierchen. 
EK.     Professor  Ehrenberg's  Kreidethierchen. 
EM.     Professor  Ehrenberg's  Mikrogeologie. 

ERBA.  or  EB.  or  ER.     Professor  Ehrenberg  in  Reports  of  Berlin  Academy. 
Ehrenberg,  Prof.     Passatstaub  und  Blutregen. 


X  LIST  OF  ABBEEVIATIONS,  ETC. 

Entw.  Colin,  Prof.  F.     Entwickeliings-gescliiclite  der  mikroskopischen  Algen  imd 

Pilze.     1854. 
Fauna  Infusoria,  Norfolk.     T.  Brightwell,  Norwich. 
Gr.     Dr.  R.  K.  Greville. 
GBF.     Dr.  R.  K.  Greville's  British  Flora. 
GCF.     Dr.  R.  K.  Greville's  British  Cryptogamic  Flora. 
Greg.     Dr.  Gregory  of  Edinburgh. 
GDC  or  GC.     Dr.  "Gregory's  Diatomacete  of  the  Clyde. 
HBA.     HassaU's  British  Algse. 
Jones,  T.  Rymer,  Prof.     A  General  Outline  of  the  Animal  Kingdom.      London, 

1841. 
K.  or  Kiitz.     Professor  Kiitzing. 
KA.  or  KSA.     Professor  Klitzing's  Species  Algarum. 
KB.     Professor  Kiitzino-'s  Bacillarien. 


Kiitzing.     Phycologia  Germanica.     1845. 
KL.     Die  kleinsten  Lebensfonnen. 


KSD.     Professor  Klitzing's  SjTiopsis  Diatomeormn. 

Linnaea,  xiv.     1840. 

Lpio-b.     Professor  Lpigbye's  Tentamen  Hydrophytologi?e  Danicee. 

Medical  Times.     Loudon,*  1856.     Professor  Huxley's  Lectures. 

Me.  or  Men.     Professor  Meneghini. 

Meneghini,  R.  S.     Professor  Meneghini  on  the  Animal  Nature  of  Diatomeae.     Ray 

Society.     London,  1853. 
Mem.  de  I'Acad.  Roy.  Belgique.     Memoires  de  I'Academie  Royale  de  Belgique. 
Micrographic  Dictionary,  The.     By  Dr.  Grifhth  and  Prof.  Henfrey. 
Microscopic  Illustrations.     By  C.  R.  Goring,  M.D.,  and  Andrew  Pritchard. 
Mittheilungen  der  Naturforschenden  Gesellschaften  in  Bern.     1849. 
MJ.  or  JMS.     Journal  of  Microscopical  Science. 
Monatsb.  Berlin.  Acad.     Monatsbericht  der  Berliner  Academic. 
MT.  or  TM.  or  TMS.     Transactions  of  Microscopical  Society. 
Miiller's  Archiv.     Archiv  fiir  Anatomic  und  Physiologic.     Yon  Dr.  J.  Miiller. 
Miiller,  O.  F.  Prof.     Animalcula  Infusoria. 
Na.  or  Nag.     Professor  Niigeli. 

Nat.  Hist.  Review.     Natural  History  Review,  Dublin. 
Nov.  Act.  Acad.  Curios.     Nova  Acta  Academiae  Naturae  Curiosorum. 
Owen,  Richard.     Lectures  on  the  InAertebrate  Animals.     London,  1843. 
Owen,  Richard.     On  Parthenogenesis.     London,  1849. 
Ph,     Professor  John  Phillips,  F.R.S. 

Phil.  Trans.     Philosophical  Transactions  of  the  Royal  Society  of  London. 
Perty,  Max.,  Dr.     Zur  Kenntniss  kleinster  Lebensformen.     1852. 
Proceedings  of  the  American  Association  for  the  Advancement  of  Science. 
Proceedings  of  the  Boston  Society  of  Natural  History. 
Proc.  Roy"^  Soc.     Proceedings  of  the  Royal  Society  of  London. 
Proc.  Roy.  Soc.  Edin.     Proceedings  of  the  Royal  Society  of  Edinburgh. 
Proceedings  of  the  Academy  of  Natural  Sciences  of  Philadelphia.     1853. 
Rab  D.  or  RD.     Dr.  Rabenhorst,  Die  Siisswasser  Diatomaceen. 
Ra.  or  R.     Mr.  Ralfs. 
R.S.     Ray  Society's  publications. 
R.S.  Reports.     Ray  Society  Reports. 
Rejuv.  R.S.      Braun,  A.,  Professor,  On   the  Phenomena  of  Rejuvenescence   in 

Nature.     Ray  Society.     London,  1853. 
Ro.     F.  C.  S.  Roper,  Esq. 
Schleiden,  J.  M.,  Prof.     Principles  of  Scientific  Botany :   translated  by  Dr.  Lan- 

kester.     1859. 
Schultze,  Dr.  Max  S.     Ueber  den  Organismus  der  Polythalamien.     Leipzig,  1854, 
Schneider,  Ant.     S^anbolae  ad  Infusoriorum  Historiam  Naturalem  Dissertatio  In- 

auguralis.     Berlin,  1854. 
Sh.  or  Shadb.     G.  Shadbolt,  Esq. 

Sill.  Joum.     Silliman's  American  Journal  of  Science  and  Arts. 
S.  or  Sm.     Professor  Smith. 

SBD.  or  SD.     Professor  Smith's  S}Tiopsis  of  British  Diatomaceas. 
Stein,  F.,  Prof.     Die  Infusionsthiere,  auf  ihre  Entwickelungsgeschichte. 


EEEATA,  ETC.  XI 

Transactions  of  the  Pliilosopliical  Societ}-  of  Manchester. 

Transactions  of  the  Medical  and  Physical  Society  of  Bombay. 

Untersuchung-en  liber  die  Familien  der  Conjiigaten.     By  Professor  de  Bory. 

Van  der  Hoeven.     Lehrbiich  der  Zootomie.     1850  &  1856. 

Wagner.     Zootomie. 

Wiegmann's  Ai'chiv.     Archiv  fiir  Naturgeschichte.     Von  A.  F.  A.  Wiegmann. 

Williamson,  Prof     On  the  Recent  Foraminifera  of  Great  Britain,     Ray  Society. 

London,  1857. 
Zeitschr.,  or  Siebold's  Zeitschr.     Zeitschrift  fiir  -mssenschaftliche  Zoologie.     Von 

Carl  T.  yon  Siebold  iind  Albert  Kolliker.     1848-59. 

Note. — The  names  of  Ehrenberg,  Dujardin,  Perty,  and  Siebold  are  frequently 
mentioned  \\dthout  particular  notice  of  the  work  quoted ;  but  the  ti'eatises  intended 
are  those  in  which  each  of  those  several  authors  has  given  a  general  history  of 
Infusoria,  and  which  are  named  in  the  above  list.  So,  in  the  account  of  the 
Rhizopoda,  Schiiltze  is  often  quoted,  his  special  work  on  their  organization  being 
referred  to ;  and  lastly,  in  the  History  of  the  Rotatoria,  the  opinions  of  Leydig  are 
all  derived  from  his  essays  in  Siebold's  'Zeitschrift.' 

For  abbreviations  employed  in  Systematic  History  of  Desmidiaceae,  see  p.  721. 

Note.  —  The  references  to  the  engravings  in  this  work  are  printed  thus : 
(xn.  20.)  for  Plate  XH.  fig.  20. 


EEEATA,    ETC. 

Page    10,  line  8  from  bottom,  dele  See  Appendix  at  end. 

—  218,  line  7  from  top,  for  Foraminiifera  read  Foraminifera. 

—  243,  line  7  from  bottom,  for  peuliarity  read  peculiarity. 

—  253,  line  3  from  top,  for  Actinopln-gs  read  Actinophrys. 

—  259,  line  4  from  bottom,  for  XVIII.  read  XXIII. 

—  316,  line  6  from  bottom,  for  Leuckhart  read  Leuckart. 

—  324,  line  14  from  bottom,  for  Wagener  read  Wagner. 

—  470,  line  7  from  top,  for  1855  read  1858. 

—  535,  line  5  from  bottom,  after  figm^ed,  inseri  subsequently. 

—  726,  col.  2,  line  20  from  bottom,  i7isert  segment  3-lobed,  before  lateral  lobes. 

—  726,  col.  2,  line  1 1  from  bottom,  for  side  read  sides. 

—  729,  col.  2,  line  25  from  bottom,  dele  comma  after  surface,  a^id  insert  after  middle. 

—  732,  col.  2,  line  22  from  bottom,  for  finely  read  finally. 

—  735,  insert  "  C.  aciculare  (West). — Elongated,  very  slender,  straight,  except  at  extre- 

mities." 

—  741,  col.  2,  transpose  reference  to  figm'e  from  8.  globulatum  to  S.  bacillare. 

—  744,  col.  2,  line  34,  for  paradoxum  read  tetracerum. 

—  753,  line  18  from  top, /or  Pediastrium  read  Pediastrum. 

—  758,  line  5  from  bottom,  dele  Synedrese.     {^See  p.  940.) 

—  760,  col.  1,  line  28,  after  capitate,  insert  strias. 

—  761,  col.  1,  line  4  from  bottom, /or  159  read  156,  and  insert  xr.  1-8. 

—  764,  for  E.  Terra  read  E.  Serra. 

—  765,  col.  2,  line  2  from  bottom,  for  Argus  read  Arcus. 

— ■  768,  after  Grenus  Oncosphenia,  insert  Genus  Podosphenia  from  p.  769. 

—  771,  col.  1,  hne  14,  for  broadly  read  loosely. 

—  772,  col.  2,  line  5  from  bottom,  for  pear-like  read  pearl-like. 

—  773,  col.  1,  line  10  from  bottom,  for  in.  read  xiii. 

—  774,  col.  1,  Hne  5,  insert  (iv.  32.) 

—  775,  transpose  Odontidium  mesodon  to  end  O.  hyemale  as  syn, 

—  775,  for  "  0.  pinnatum  "  read  pinnulatum. 


Xll  ERE  AT  A,  ETC. 

Page  777,  end  of  F.  virescens,  insert  (ix.  176.) 

—  778,  line  6,  after  Ralfs,  msert . — 

—  779,  before  Genus  Nitzseliia,  insert  Fam.  characters  of  Surirellege  from  p.  783 ;  and  see 

Note,  p.  940. 

—  781,  col.  1,  Hne  2  from  bottom,  for  20  read  21. 

—  783,  col.  1,  line  12,  for  22  read  23. 

—  784,  col.  1,  line  5  from  bottom,  for  2,  3 ;  read  24. 
~  784,  col.  2,  line  22  from  bottom,  for  19  read  20. 

—  786,  S.  pulehella,  insert  (iv.  28.) 

—  789,  S.  fulgens,  i72sert  (xiii.  20.) 

—  791,  col.  1,  line  2,  for  xviii.  read  vrii. 

—  796,  S.  striatula,  insert  (ix.  137,  138.) 

—  798,  col.  1.  line  24,  for  diyiduate  read  dimidiate. 

—  799,  col.  1,  line  21  from  bottom,  for  magnificent  read  marginal. 

—  802,  col.  2,  line  14,  for  xv.  read  xii. ;  line  29,  for  xv.  read  xir. ;  last  figure,  for  56 

read  50. 

—  806,  Gomphogramma  rupestre,  insert  (iv.  46.) 

—  806,  Tetracyclus  lacustris,  ijisert  (viii.  10.) 

—  809,  Gephyria  incxwratsi,  insc7't  (v.  50.) 

—  809,  Gephyria  media,  insert  (v.  49.) 

—  809,  Eupleuria  pulehella,  insert  (viii.  2.) 

—  812,  for  G.  undulata  read  C.  midata. 

—  821,  col.  2,  line  6,  after  ochracea,  insert  (Ralfs)  from  next  line;  and  after  ferruginea 

insert  (Elir.). 

—  836,  col.  2,  line  8  from  bottom,  for  x.  read  xi. 
— •  844,  A.  Kittoni,  insert  (viii.  24.) 

—  851,  col.  1,  line  17  from  bottom,  for  nervosa  read  enervis. 

—  863,  Dicladia  Capreolus,  insert  (vi.  28.) 

—  875,  CymbeUa  Arcus,  insert  (vii.  78.) 

—  891,  col.  1,  line  2  from  bottom,  for  xir.  read  xi. 

—  893,  for  "N.  dissimUis  (Rab.)"  read  "N.  clepsydra  (Ralfs)." 

—  903,  for  "  N.  jiroducta  "  read  "  N.  extensa." 

—  911,  S.  Fidmen  (Breb.),  read  "S.  Fuhnen  (Bri.),"  and  insert  that  species  after  S.  con- 

stricta. 

—  923,  col.  1,  last  line,  for  (viii.  43.)  read  (viir.  48.) 

—  929,  col.  1,  top  line,  for  octocarpoides  read  ectocarpoides. 

—  938,  col.  1,  line  9,  for  "  C.  radiata'^  read  "  C.  stylorumy 

—  941,  Actinoptychvis  Jupiter,  now  Actinocyclus  Ehrenbergii. 

—  952,  in  description  of  Plate  VII.,  insert  "  78.  CymbeUa  Arcus,  to  right  of  fig.  42. 

79.  AmjDhora  monilifera,  to  right  of  fig.  49."     {Note.    The  engraver  has  omitted 
the  numbers  to  these  two  figures  in  that  Plate.] 


WORKS  BY  THE  SAME  AUTHOE. 

MICROSCOPIC  ILLUSTRATIONS,  with  Descriptions  of  the  New  Microscope?, 
Rules  for  constructing  them,  and  Directions  for  their  management, 

MICROSCOPIC  CABINET,  with  Descriptions  of  the  Jewel  and  Doublet  Micro- 
scopes, Test  Objects,  &:c. 

MICROGRAPHIA,  with  practical  Essays  on  Eye-pieces,  Solar  and  Gas  Micro- 
scopes, &c. 

NOTES  ON  NATURAL  HISTORY,  selected  from  the  ^Microscopic  Cabinet,' 
with  10  coloured  Plates  from  original  Drawings  by  C.  R.  Goring,  M.D. 

MICROSCOPIC  OBJECTS  :  Animal,  Vegetable,  and  Mineral. 

A  LIST  OF  ENGLISH  PATENTS  for  the  first  Forty-five  Years  of  the  present 
Century. 


PART  I. 
A  GENERAL  HISTORY  OF  INFUSORIA 


Sect.  I.— OF  THE  BACILLARIA. 

Under  this  designation,  contrived  by  Ehrenberg,  two  families  of  microscopic 
unicellular  Alga)  are  comprehended,  viz.  the  Desmidie^.  and  the  Diatome^. 

The  Diatomea)  differ  from  the  Desmidieae  chiefly  by  their  dense  silicious 
envelope,  composed  of  two  opposite  portions  or  valves  and  of  an  interposed 
segment,  and  by  the  general  absence  of  the  usual  green  colouring  matter  of 
plants — chlorophyll  or  chromule.  The  Desmidieae,  on  the  contraiy,  have  a 
non-sihcious  envelope,  separable  into  two  segments,  and  filled  with  bright 
grass-green  chromule.  In  various  vital  phenomena  the  two  tribes  accord ; 
but  whilst  the  Desmidieoe  are  all  but  universally  admitted  to  be  plants,  the 
Diatomese  are  still  regarded  by  many  to  be  of  an  animal  natm-e.  With  respect 
to  this  question,  the  arguments  ^^ro  and  con.  wiU  be  best  understood  when 
•the  organization  and  vital  endowments  of  these  beings  have  been  discussed. 

I.— OF  THE  FAMILY  DESMIDIE^  OR  DESMIDIACE^. 
(Plates  I.  II.  III.  and  XYI.) 

The  Desmidiese  are  (pseudo-)uniceUular  Algae  of  a  herbaceous  green  colour, 
of  freshwater  habit,  and  have  a  membranous  lorica  composed  of  two  symme- 
trical segments  or  valves.  In  Kiitzing's  arrangement  {8p.  Alg.),  the  Desmidieae 
constitute  a  family  of  the  Chamaephyceae,  a  suborder  of  the  class  Isocarpeae. 
Ehrenberg  treated  the  genus  Closterium  as  a  distinct  family,  which  he  placed 
between  the  Yibrionia  and  Astasiaea,  with  the  name  Closterina. 

That  the  Desmidieae  are  actually  unicellular  (in  the  sense  of  forming  a 
single  enclosed  cavity),  Mr.  Ralfs  has,  in  his  most  valuable  monograph  on  the 
family  (1848),  taken  much  pains  to  demonstrate.  0^^dng  to  the  very  deep 
constriction  of  the  fronds  of  many  genera,  e.  g.  of  Euastrum  and  Micrasterias, 
the  appearance  of  the  little  organism  is  that  of  two  cells  united  by  a  narrow 
band  (I.  1,  2,  24,  26,  27;  II.  18,  28),  forming,  in  Ehrenberg's  opinion,  a 
binary  cell  or  frustule.  However,  between  such  deeply  partite  forms,  and 
others  in  which  no  constriction  is  j)erceptible,  for  instance  in  Closterium, 
eveiy  intermediate  gradation  is  met  with.  Other  evidence  of  the  unicellular 
structure  is  afforded  by  the  phenomena  of  conjugation  and  of  the  formation 
of  sporangia,  by  the  newly-formed  segments  resulting  from  self-fission  being 
interposed  between  the  old  valves,  and  by  the  fact  that  the  entire  contents 
wiU  escape  through  an  opening  made  in  either  valve.  Moreover,  in  several 
genera  the  circulation  of  portions  of  the  contents  throughout  the  frond,  from 
one  segment  to  the  other,  clearly  demonstrates  the  continuity  of  their  interior. 

Figure. — There  is  great  variety  in  the  fig-ure  of  Desmidieae,  and  much 


2  GENEEAL  HISTORY  OF  THE  INFUSOEIA. 

beauty.  This  will  be  best  illustrated  by  reference  to  the  Plates  I.  and  II. ;  for 
description  alone  would  fail  to  convey  even  a  tolerably  accurate  conception. 
In  Micrasterlas  (I.  18,  20,  21)  the  frustule  has  a  general  circular  outhne,  but 
is  bipartite  and  variously  cut.  In  Euastrum  (I.  23,  24,  26 ;  II.  10)  it  is 
bipartite,  and  each  valve  deeply  sinuated.  In  many  species  of  Cosmarium 
(1. 1,  2 ;  II.  33)  the  constriction  is  much  shallower,  the  valves  hemispherical, 
and  their  margin  entire.  In  Staurastrum  (I.  31-34 ;  II.  3,  7)  each  segment 
is  more  or  less  irregularly  produced  at  the  extremities  into  horn-like  pro- 
cesses. In  Penium,  Docidium,  and  Clostermm  (II.  1,  2,  9,  14)  the  frond  is 
elongated  and  wand-Hke,  without  constriction,  or  with  only  a  very  faint  one, 
and  in  many  species  is,  moreover,  curved  or  crescentic.  Not  a  few  genera 
present  numerous  fronds  united  together ;  the  outline  of  the  compound  being 
will  consequently  vary,  both  according  to  the  figure  of  each  individual  frond, 
and  especially  to  the  mode  in  which  the  several  fronds  are  united.  Thus  in 
HyaTotluca,  Desmidium,  and  other  genera  (II.  35,  37,  39),  the  quadrate 
fronds  are  united  side  by  side  in  single  series,  so  as  to  foim  a  chain  or 
filament,  in  other  words  are  concatenated. 

The  lateral  view  or  cross-section  of  the  fronds  furnishes  valuable  characters, 
and  is  largely  made  use  of  by  Mr.  Ralfs  with  that  object,  especially  to  distin- 
guish between  the  several  filamentaiy  species.  His  figures  show  that  the 
fronds  may  be  more  or  less  compressed,  and  consequently  offer  on  a  transverse 
section  (end  view)  an  oval  and  more  or  less  acuminate  form  (I.  25  ;  II.  23, 
29),  further  modified  by  the  elevations  and  depressions  which  the  surfaces 
possess  (I.  25  ;  II.  23).  In  other  cases  the  section  is  circular,  e.  g.  in  ffya- 
lotheca  and  Didymoprium  (II.  32,  38),  whilst  in  others,  again,  three  or  four 
sides  exist  which  are  commonly  concave,  as  m  Desmidmm  (II.  40). 

The  end  view  exhibits  the  arrangement  of  the  mass  of  chlorophyll,  which 
in  some  instances  would  appear  to  be  pecuhar  and  determinate  of  species. 

The  appearance  of  the  Desmidiese  is  much  modified  by  the  sinuosities, 
eminences,  depressions,  and  processes,  as  well  of  the  sm-face  as  of  the  margin 
of  the  fronds,  and  also  by  the  depth  and  width  of  the  central  constriction. 
The  surface  may  be  dotted  over  irregularly,  or  more  often  regularly  :  the  dots 
themselves  are  in  most  cases  elevated  points,  and  in  fewer  instances  depressions. 
An  irregular  distribution  of  minute  dots  produces  a  granular-looking  surface 
(I.  24 ;  II.  23,  30).  Where  the  spots  are  larger  their  elevated  character 
becomes  e\ident  on  the  margin,  to  which  they  give  a  finely-toothed  or  dentate 
appearance,  e.  g.  in  CosmciHum  (I.  1,  2,  3).  In  some  elongated  fonns,  such 
as  Tetmemorus  and  Penium  (II.  15),  the  puncta  are  disposed  in  lines  parallel 
to  the  length :  in  Docidium,  however,  the  disposition,  so  far  as  regular,  is 
transverse.  In  several  examples  the  surface  is  marked  by  elevated  hues  or 
by  furrows  (II.  6).  Such  markings  seem  peculiar  to  the  elongated  genera, 
particularly  to  Closterium. 

Many  apparent  lines  are  resolvable  by  higher  magnifying  powers  into  rows 
of  puncta.  Where  the  lines  are  fine,  they  are  said  to  produce  a  striation  of 
the  surface,  as  in  Closterium  attenuatum  and  C.  acerosum ;  where  they  are 
more  distinct  they  are  termed  costa?,  and  the  surface  they  cover  is  costate  or 
ribbed,  as  in  Closterium  costatum  and  C.  angiistatum.  In  general,  in  order 
to  discover  the  striation  of  the  surface,  the  fronds  must  be  viewed  when 
empty ;  sometimes  indeed  the  Hues  can  be  made  out  at  the  extremities  which 
are  unoccupied  by  chlorophyll. 

The  strige  and  costae  of  Closterium  and  Penium  referred  to  are  disposed 
longitudinally,  but  frequently  they  are  intersected  at  one  or  more  points  by  a 
transverse  line.  In  these  spindle-shaped  genera,  where  no  constriction  is 
found,  one  such  transverse  line,  usually  central,  is  constant,  and  indicates 


OF  THE  DESMIDIE.E.  3 

the  point  of  separation  into  two  valves  (II.  1,  2,  9).  Each  valve  again  is 
occasionally  subdivided  by  another  line  (II.  6,  15).  These  lines  may  be 
single  or  double,  and  in  the  case  of  the  middle  suture  their  number  may  be 
more  multiplied,  as  in  Closterimn  lineatum  and  C.  Rcdfsii.  The  median 
sutiu^al  line  is  e\ddent  in  other  genera,  e.  g.  in  Hyalotheca,  Cosmarhim,  and 
Euastrum  (II.  35).  In  several  it  takes  on  a  further  development,  and 
becomes  an  elevated  ridge  or  band,  appearing,  in  a  front  \iew,  as  a  double 
line,  terminating  on  each  margin  in  a  dentation.  Instances  occur  in  Docidium 
and  in  DidymoiJrmm  (II.  9,  39).  Such  double  lines  are  also  sometimes  met 
with  on  each  side  the  median  suture,  and  at  others,  among  the  concatenate 
forms,  at  the  junction-siu'faces  of  connected  fronds. 

That  the  dots  or  pimcta  on  the  surface  of  the  frustules  are  commonly  small 
elevations  has  already  been  stated;  a  further  development  of  such  into 
papillae  or  minute  spines  crowned  by  a  globular  apex  is  seen  in  Micrasterias 
jpapUlifera ;  whilst  in  many  Cosmaria  and  Staurastra,  the  edge  or  the  entire 
surface  is  bedecked  by  fine  hair-like  spines  or  by  obtuse  ones,  looking  on  the 
margin  like  crenations  (I.  1,  2,  3).  When  short  and  stout,  many  elevated 
processes  of  the  surface  are  called  tubercles  (II.  16,  17)  ;  when  long  and 
tapering,  they  constitute  spines,  and  in  this  form  may  be  either  straight  or 
curved :  such  are  especially  produced  from  the  angles  of  the  fronds,  as  in 
Arthrodesmus  (II.  18,  28).  Among  the  Staurastra,  illustrations  of  forked 
spines  (II.  3,  7)  are  found  ;  whilst  among  sporangia  of  many  species,  spinous 
processes,  besides  tubercles  and  other  appendages,  are  highly  develoi)ed  (II. 
22,  25,  34)  and  attain  their  most  complex  conditions. 

The  modification  of  surface  in  several  genera  seems  due,  not  to  mere  simple 
appendages,  but  to  positive  expansions  of  the  limiting  membrane  itself  into 
thick  processes,  which  in  their  turn  usually  end  in  spines ;  instances  occur 
in  Xanthidium  and  Staurastrum  (I.  27,  28 ;  II.  3,  7,  20,  25).  Generally 
these  large  productions  from  the  surface  occupy  constant  and  definite  positions, 
such  as  the  extremities,  the  rounded  angles  of  the  fronds,  or  a  margin,  and 
are  rarely  indifferently  placed.  A  general  distribution  over  the  surface  is 
rather  characteristic  of  Xanthidimn  (I.  27,  28).  In  Euastrum  the  surface  is 
thrown  into  very  broad  round  swellings,  hence  caUed  inflations ;  such  may  be 
presumed  to  be  constant  in  number  and  position  (I.  24,  II.  30,  the  empty 
divided  fronds). 

The  margin  of  the  more  flattened,  and  the  extremities  of  the  elongated,  spe- 
cies furnish  important  specific  and  generic  characters.  Micrasterias  has  its 
margin  deeply  incised  into  lobes  (1.18,  20,  21,  22),  which,  with  reference  to  the 
centre  of  the  frond,  have  a  radiating  arrangement,  and  are  themselves  incised 
or  inciso- dentate.  The  fronds  of  Euastrum  are  more  or  less  deeply  sinuated 
(I.  23,  24,  26 ;  II.  10),  and  the  intermediate  lobes  produced  vary  both  in 
dimensions  and  outline.  Where  the  lobes  on  the  margin  of  fronds  are  small 
and  little  prominent,  they  constitute  crenations  and  dentations  which  may 
occur  singly  or  in  paii'S  ;  in  the  latter  case,  the  margin  so  modified  is  said  to 
be  bidentate  or  bicrenate  (I.  1,  2,  3 ;  II.  31,  26,  37).  For  example,  some 
fronds  of  Euastrum  binatum  are  bicrenate  on  the  sides,  and  those  of  Didy- 
moprium  at  the  angles  of  the  filaments  (II.  39),  whilst  bidentate  frustules 
are  seen  in  Desmidium  (II.  37),  and  in  Hyalotheca  mucosa.  It  has  been 
before  remarked  that  when  the  surface  is  covered  by  tubercular  eminences 
or  conical  granules,  a  dentate  outline  is  produced ;  instances  of  this  occur  in 
EimMrum  verrucosum  and  in  several  Cosmaria.  Another  variety  of  margin 
exists,  known  by  the  term  undulated  or  wavy,  where  its  elevations  and  de- 
pressions are  comparatively  shallow.  Lastly,  the ,  general  concavity  or  the 
convexity  of  the  margin  furnishes  other  specific  characteristics. 

b2 


4  GENERAL  HTSTOEY  OF  THE  INFUSORIA. 

Among  the  variations  in  the  ends  of  the  fusifonn  or  elongated  genera  may 
be  noticed  the  notched  or  emarginate  apices  of  Tetmemorus  (II.  12);  the 
truncate  extremities  of  Docidium  (II.  9,  10),  sometimes  also,  as  in  D. 
Ehrenbergii,  tnberculate;  and  the  more  or  less  acutely  conical  apices  of 
Closterimn,  prolonged  in  some  species,  as  in  0.  attemiatum,  by  an  abrupt 
contraction  of  the  frond  into  a  conical  process — in  others,  as  in  C.  setaceum 
and  G.  rostratum,  by  the  gradual  tapering  of  the  whole  frond — into  long 
rostrate  or  setaceous  beaks. 

Colour. — This  is  due  to  the  endochrome  or  internal  substance,  which  is 
usually  of  a  herbaceous  green  colour,  and  often  diffused  pretty  uniformly 
throughout  the  fronds,  sometimes  however  leaving  intervals  at  which  the 
enclosing  membrane  (lorica,  Ehr.)  becomes  visible.  This  lorica  is  itself 
mostly  coloiuiess ;  yet  in  several  species  of  Closterium  and  Penium  it  has  a 
reddish-brown  tint  (II.  5,  6, 15).  The  green  colouiing  matter  of  the  interior 
is  identical  with  that  of  plants,  i.  e.  it  is  chlorophyll  or  chromule,  and  con- 
sequently undergoes  a  change  of  coloui'  in  autumn,  becoming,  like  the  leaves 
of  plants  at' that  season,  a  reddish-brown.  When  this  change  occiu's,  it  is 
equally  indicative  of  the  termination  of  hfe. 

Consistence. — Envelopes. — The  hmiting  membrane  of  Desmidiaceae  is 
firm,  though  flexible ;  it  exhibits  some  elasticity  and  considerable  resistance 
to  pressure,  is  not  brittle,  and  not  readily  decomposable.  Traces  of  siHca  are 
found  in  a  few  species,  but  not,  says  Mr.  Ralfs,  "  in  sufficient  quantity  to 
interfere  with  their  flexibility."  It  is  lined  by  a  softer  flexible  membrane ; 
and  besides  this,  the  Desmidieae  generally  have  an  external  mucous  or  gela- 
tinous covering,  mostly  so  transparent  and  homogeneous  as  to  be  overlooked. 
To  bring  it  into  view,  it  is  a  common  plan  to  add  some  colouring  matter  to 
the  water  in  which  the  organism  is  viewed ;  but  good  manipulation  with  a 
high  power  will  frequently  succeed  without  recoiu-se  to  this  expedient  to 
demonstrate  it.  The  particles  of  colour  diffused  about  the  frond,  and  indeed 
any  external  bodies,  such  as  small  vegetable  cells,  are  seen,  not  in  contact 
with  the  fronds,  as  they  would  often  be  if  these  were  naked,  but  kept  at  a 
distance  corresponding  with  the  width  of  the  hyahne  envelope  (I.  15  ;  II.  35). 
In  Didymoprium  GrevUlii  and  Staurastrum  tumidum  the  mucous  sheath  is 
distinct  and  well  defined ;  "  in  others  (to  quote  Mr.  Ealfs)  it  is  more  atte- 
nuated .  .  .  . ,  and,  in  general,  its  quantity  is  merely  sufficient  to  hold  the 
fronds  together  in  a  kind  of  fihny  cloud  which  is  dispersed  by  the  shghtest 
touch.  AATien  they  are  left  exposed  by  the  evaporation  of  the  water,  this 
mucus  becomes  denser,  and  is  apparently  secreted  in  larger  quantities  to 
protect  them  from  the  effects  of  drought." 

The  hning  or  the  primordial  membrane  of  the  firm  lorica  is  thin,  colourless, 
and  highly  elastic,  and  alters  its  contour  with  the  varying  movements  of  the 
endochrome  which  it  immediately  invests.  It  is  in  contact  with  the  outer 
case  only  at  some  points,  mostly  about  the  centre,  and  being  elsewhere  free, 
an  intei-val  exists  between  the  two  envelopes.  This  elastic  lining  is  acted  on 
by  various  chemical  reagents  ;  for  instance,  it  is  contracted  or  connigated  by 
iodine  and  by  acids. 

Openings  in  Lorica. — Openings  have  been  represented  by  several  writers 
in  the  finn  envelopes  of  Desmidieae,  and  more  particularly  in  those  of  Clos- 
terium. Ehrenberg,  for  instance,  stated  that  apertures  existed  at  the  extre- 
mities, through  which  soft,  veiy  short,  and  conical  transparent  papiUae 
shghtly  protruded  to  serve  as  locomotive  organs.  Both  Mr.  Varley  and  Mr. 
Daliymple  also  described  tenninal  orifices,  closed  within,  however,  by  a  mem- 
branous envelope ;  but  neither  they  nor  any  other  observers  have  detected 
the  papilla-Hke  locomotive  organs  Ehrenberg  represented.     '^  In  no  instance 


OF  THE  DESMIDIE^. 


(Mr.  Balfs  says)  can  any  portion  of  the  contents  of  the  cell  be  forced  out  from 
the  extremities."  More  recently  the  belief  in  terminal  apertures  has  been 
revived  by  the  published  researches  of  the  Kev.  Mr.  Osborne  and  others 
(J.  M.  S.),  who  affii-m,  that  not  only  the  outer  hard  case,  but  also  the  mem- 
branous lining  is  penetrated  by  foramina,  through  which  water  enters  from 
without  into  the  ca\-ity  of  the  frond.  Another  writer  in  the  Mic.  Journ.,  Dr. 
"Wright,  describes,  in  a  specimen  of  CJosterium  didymotieum,  certain  circular 
markings,  consisting  of  two  concentric  ring-s,  as  apertui^es  penetrating  "  both 
layei-s  of  the  investing  membrane  at  irregular  intervals:"  yet  neither  the 
character  of  these  circular  bodies,  as  represented  by  their  observer,  nor  their 
irregular  distribution,  countenances  such  a  notion,  and  the  appeal  he  makes 
to  Mr.  Ealfs's  figures,  instead  of  aiding  his  argument,  is  totally  subversive  of 
it ;  for  although,  in  the  fronds  of  Closterium  didymotieum  and  of  C.  Balfsiij 
some  large  globules  are  distinguishable,  these  are  in  single  linear  series  in  a 
definite  and  constant  position,  except  when  disturbed  from  it  by  the  death  of 
the  plant,  or  by  its  exhaustion  by  parasitic  growths  upon  it,  and  clearly  are 
not  aperiui'es.  Besides,  any  such  globules  are  sought  in  vain  when  the  frond 
is  empty,  as  Mr.  Ralfs  distinctly  shows  by  his  figiures ;  whereas  if  they  were 
openings,  they  would  then  be  more  evident  than  when  the  fnistule  is  filled 
with  its  endochrome,  Mr.  Wenham  {J.  M.  S.  1856,  p.  159)  has  been  un- 
able to  confiim  the  presence  of  apertiu'es,  and  writes — "  It  may  be  assumed 
that  if  such  an  opening  existed  it  would  have  something  like  a  structui'al 
margin  of  such  a  size  as  to  allow  its  position  at  least  to  be  visible  under  the 
microscope,  but  not  the  slightest  break  can  be  observed  in  the  laminated 
structui-e  that  the  thickened  ends  display." 

MovEME]!f TS  AJfD  EXTERNAL  CiLiA. — By  coutiuued  observation  the  Desmidieai 
are  seen  to  move  very  slowly  onwards,  or  with  an  oscillating  movement 
backwards  and  forwards.  This  phenomenon  is  most  notable  in  the  long 
spindle-shaped  fronds  of  the  genus  Closterium ;  in  others  it  is  scarcely,  in 
many  not  at  all,  cognizable.  Ehrenberg  having  persuaded  himself  of  the 
existence  of  pedal  organs  or  papillae  at  the  extremities  of  the  fronds  of  Clos- 
terium, found  no  difficulty  in  explaining  their  locomotion;  but  other  observei^, 
who  deny  the  presence  of  such  organs,  have  been  compelled  to  seek  some 
other  explanation  of  the  subject.  Some  have  referred  the  locomotion  to  the 
influence  of  the  vital  acts  taking  place  within  the  organism,  to  the  extri- 
cation of  gas,  &c. ;  others  again,  particularly  of  late,  have  attributed  it  to 
the  presence  of  cilia  covering  the  suiface.  This  latter  hypothesis  is  sup- 
ported chiefly  by  the  Rev.  Mr.  Osborne  and  Mr.  Jabez  Hogg,  who  represent 
these  organs  as  covering  the  fronds  of  Closteymmi,  of  Staurastruin,  and  of 
other  Desmidieae  (see  page  7,  on  the  Circulation).  Mr.  Wenham  has 
sought  cilia  in  vain,  and  attributes  the  supposition  of  their  existence  to  an 
optical  illusion.  Powerful  oblique  sunlight,  which  is  found  necessary  to 
display  the  apparent  ciliary  movement,  this  obseirver  remarks,  "  causes  a 
refractive  atom  to  appear  elongated  as  a  ray  or  line  .  .  . . ,  and  this  line  also 
to  appear  to  extend  over  the  boimdary  of  a  cell- wall  or  other  a^oining  body: 
another  cause  of  deception  arises  from  a  large  angle  of  aperture."  The  pos- 
sibility of  such  errors  he  illustrates  by  reference  to  the  circulation  as  seen 
in  Anacharis.  In  those  fronds  invested  with  a  mucous  sheath,  cilia  on  the 
surface  of  the  lorica  could  perform  no  locomotive  function,  and  therefore  can 
scarcely  be  supposed  present.  Likewise  in  the  concatenated  species  they 
cannot  be  looked  for,  since  any  movements  they  possess  are  of  that  general 
sort  seen  in  other  filiform  Algae,  springing  from  vital  action  under  the 
influence  of  light. 

Apart  from  this  inconsiderable  movement,  seen  under  the  microscope,  the 


6  GEIfEEAL  HISTORY  OF  THE  INFTJSOEIA. 

Desmidieae  are  known  to  move  through  considerable  spaces.  They  travel 
towards  the  light ;  appear  on  the  side  of  the  vessel  on  which  the  Hght  falls, 
or  rise  to  the  surface  and  form  a  peUicle  upon  it.  These,  and  the  analogous 
fact  of  their  penetrating  to  the  surface  of  mud  in  which  they  have  been 
imbedded,  when  exposed  to  light,  are  phenomena  common  to  the  Desmidiea? 
with  other  Algae.  ''Another  proof  (writes  Mr.  Ealfs)  of  their  power  of 
locomotion  is  afforded  by  their  retiring  in  some  instances  beneath  the  siui'ace 
when  the  pools  diy  up,"  a  phenomenon  witnessed  also  in  the  case  of  other 
plants.  Braun  {R.  S.  p.  203)  casually  refers  to  this  kind  of  motion,  dependent 
on  the  resumption  of  vital  action.  The  Penium  curtum  {Cosmarium  curtum, 
Ralfs),  which  grows  ''  in  rain-pools  which  are  altemately  quickly  filled  and 
dried  up  in  the  changes  of  the  weather,  ascends  from  the  muddy  bottom, 
when  the  pools  fill,  in  the  form  of  beautiful  bright  green  clouds,  produced 
by  the  social  growth  and  the  very  fluid,  widely- extended  gelatinous  invest- 
ment of  the  cells."  The  movement  of  this  plant,  it  is  added,  is  more  active 
and  more  regular  than  that  of  other  Desmidieae,  and  "it  is  a  remarkable 
sight  to  behold  all  the  individuals  in  a  dish  of  water  in  a  short  time  turn 
their  long  axes  towards  the  hght,  and  thus  arrange  themselves  in  beautiful 
streaks  in  the  gelatinous  mass.  Observation  likewise  shows  that  it  is  the 
younger  haK  of  the  cell,  distinguishable  as  such  for  a  long  time  after  division, 
which  here  turns  towards  the  hght." 

Contents  of  Feonds. — The  contents  of  the  fronds  or  frustules  of  Desmidieae 
are  designated  generally  by  the  name  of  Endochrome.  This  endochrome,  we 
have  already  remarked,  is  of  a  grass-green  colour,  and  contained  in  a  proper 
sac  hning  the  denser  lorica.  It  is  not  homogeneous,  but  presents  nmnerous 
globules,  small  vesicles,  and  many  refracting  coipuscles ;  it  is  commonly 
not  unifonnly  diffused,  but  collected  in  a  definite  manner,  and  it  either  com- 
pletely fills  its  sac  or  leaves  it  unoccupied  at  parts,  which  not  seldom  are 
constant  in  position  and  aspect.  The  appearance  of  the  endochrome  is 
modified  by  age,  by  external  physical  circumstances,  and  by  the  process  of 
development.  Nageh  and  Braun  describe  it  as  constituting  two  layers 
within  the  primordial  utricle,  viz.  an  outer  and  an  inner  mucilaginous  layer, 
the  latter  the  thicker  of  the  two. 

Ehrenberg,  influenced  by  his  behef  of  the  animal  natiu^e  of  the  Desmidiaceae, 
and  by  his  pecuhar  h}^3othesis  of  their  polygastric  organization,  represented 
the  larger  vesicles  or  globules  to  be  digestive  sacs  or  stomachs,  and  the 
smaller  green  corpuscles,  ova.  He  even  exerted  his  imagination  still  fiu-ther, 
by  announcing  that  in  Micrasterias,  Arthrodes^nns,  and  one  or  two  other 
genera,  male  reproductive  stmctiu^es  are  visible.  These  suppositions  it  is 
not  necessary  to  disciiss,  seeing  that  they  are  unsupported  by  any  facts  in 
the  stnictiu'e  and  oeconomy  of  this  family. 

The  globules  and  corpuscles  of  the  endochrome  of  Desmidieae  seem  to 
differ  in  no  respect  from  those  in  other  Algae,  consisting  of  chlorophyll, 
starch,  and  of  oily  materials  floating  in  a  wateiy  medium.  In  most  species 
of  Closterium  and  of  Tetmemorns,  some  large  diaphanous  vesicles  are  con- 
spicuous, either  disposed  irregularly,  or  more  frequently  in  a  single  longi- 
tudinal series  (II.  1,  12,  13).  These  have  the  appearance  of  being  distinct 
cells ;  and  Mrs.  Thomas  has  indeed  described  two  such,  of  large  size,  in 
Cosmarium  margaritiferum,  as  ''  vesicles  filled  with  mo\dng  granules."  No 
doubt  many  of  the  apparent  vesicles  are  nothing  more  than  vacuoles  which, 
as  in  other  protoplasmic  substances,  tend  to  arise  in  the  ceU-contents,  and 
may  assume  a  fixity  in  size  and  in  position. 

The  several  species  of  Closterium  and  of  Docidium,  and  some  of  Penium^ 
present  also,  at  each  extremity  of  the  endochrome  (II.  2,  9,  14),  ''  a  large 


OF  THE  DESMIDIE^.  7 

hyaline  or  straw-coloured  globule  which  contains  minute  granules  in  con- 
stant motion."  It  is  seen  even  in  the  earhest  stage  of  the  frustules,  but 
disappears  in  dried  si)ecimens. 

In  addition  to  these  strictures,  distinguishable  in  certain  genera  only, 
Nageli  and  others  state  that  a  central  nucleus  exists  in  all  the  Desmidiese, 
mostly  containing  within  itself  a  nucleolus.  "  In  CJosterium  (Braun  writes) 
the  nucleus  with  its  colourless  mucilaginous  envelope  is  maintained  in  the 
centre  of  the  spindle-shaped  cell  by  the  green  lamellae  of  contents,  arranged 
radiantly  around  the  long  axis  of  the  cell,  which  lameUae  are  interrupted  by 
it  in  the  middle  of  the  cell.  In  many  cases  it  seemed  to  be  surrounded  as 
by  a  band,  or  by  a  cavity  containing  water." 

Niigeli  affirms  that  "  Artlirodesmus  possesses  a  small  colourless  corpuscle  on 
the  wall  of  the  cell,  which  looks  like  a  nucleolus.  Euastrum  also  exhibits 
frequently  among  the  green  contents  two  obscure  bodies  resembling  nuclei, 
always  one  in  each  half,  when  the  division  through  the  middle  takes  place. 
These  are  not  attached  to  the  ceU-membrane,  but  lie  free  in  the  midst  of  the 
cavity :  they  appear  to  possess  a  dark  centre  (nucleolus)  and  a  clear  peri- 
pheiy  (enveloping  layer  ?)....  In  CJosterium  a  nucleus  lies  in  the  centre 
which  possesses  a  thick  whitish  nucleolus  within  a  clear  enveloping  layer. 
It  is  coloured  brown  by  iodine,  and  wholly  resembles  the  nucleus  in  S;pi- 
rogyra."  Probably  the  vesicles  mentioned  and  fig-ured  by  Mrs.  Thomas  are 
really  nuclei  (I.  2,  5). 

There  is  something  special  in  the  disposition  of  the  endochrome  in  very 
many  of  the  Desmidieae.  On  a  front  view  of  Desmidium,  the  endochrome  is 
divided  into  Hnear  portions  by  a  pale  transverse  line  between  the  angles ; 
and  on  a  transverse  view  it  is  seen  to  send  out  as  many  thick  rays  as  the 
cell  has  angles.  Again,  in  Cosmarmm  Ealfsii  the  endochrome  is  somewhat 
radiate ;  but  it  is  in  the  elongated  genera,  in  Penium  and  Closterium,  that 
its  disposition  is  most  characteristic.  In  both  these  genera  the  green  matter 
of  the  endochrome  seems  condensed,  so  as  to  produce  broad  longitudinal  bands 
(II.  2,  14),  technically  called  fillets,  which  have  their  continuity  always 
interrupted  at  the  median  transverse  suture,  and  in  several  examples  of  the 
genus  Penium  by  three  cross  bands.  These  fillets  are  more  or  less  strongly 
marked  in  different  cases,  and,  it  may  be,  are  constant  in  number  in  the  same 
species.  Mr.  Ralfs  (p.  159)  tells  us  that  Meneghini  considers  them  of  too 
much  importance  to  be  omitted  in  the  specific  definition.  They  may  occa- 
sionally be  useful  in  discriminating  nearly  allied  forms ;  but  as  they  are  fre- 
quently indistinct,  or  from  various  causes  not  readily  counted  with  certainty, 
he  is  unwilling  to  introduce  them  into  the  specific  characters,  except  in  the 
absence  of  more  permanent  marks  of  distinction. 

Circulation  of  Contents. — A  circulation  or  rotation  of  much  of  the  liqiiid 
contents  may  frequently  be  seen  in  the  Desmidieae.  The  Closteria  afibrd  the 
best  subjects  for  witnessing  this  phenomenon,  but  careful  focusiag  and  other 
microscopical  adjustments  are  always  needed  to  display  it.  Even  Mr.  Ealfs 
had  failed  to  observe  it  until  he  watched  it  in  conjunction  with  Mr.  Bower- 
bank,  in  Closterium  Lunula  and  in  Penium  Digitus, 

Since  Mr.  Ralfs's  account  was  wiitten,  much  more  attention  has  been 
bestowed  on  this  phenomenon ;  and  it  has  been  observed  by  eveiy  micro- 
scopist  who  has  sought  for  it.  The  Eev.  Mr.  Osborne  has  particularly  studied 
it,  and  has  come  to  the  conclusion  that  it  is  due  to  ciHary  action.  "  If 
(he  writes,  J.  M.  S.  ii.  235)  I  put  a  specimen  on  the  stage,  cover  the  stage 
so  as  to  exclude  the  hght,  use  the  parabolic  illuminator  with  the  direct  hght 
of  the  sun,  in  certain  focal  positions  I  see  what  appear  to  be  cilia  working 
evenly  and  continuously  along  the  whole  external  margin  of  the  plant.     I 


8  GEXETIAL  HISTORY  OF  THE  INFUSORIA. 

am  inclined  to  believe  that  this  is  not  so,  that  this  is  some  ocular  deception, 
and  that  these  ciha,  so  seen,  are  within  the  outer  case.  It  may  be  that  these 
cilia  are  on  the  external  surface  of  the  membranous  sac,  as  well  as  over  the 
endochrome ;  more  practised  observers  with  higher  powers  may  yet  determine 
that.  Of  the  existence  of  the  cilia  throughout  the  plant  there  can  be  no 
doubt,  and  no  object  I  have  ever  seen  will  bear  comparison  with  this  when 

beheld  under  sunhght It  is  seldom  that  I  can  trace  a  current  up  one 

margin,  and  round  the  point  down  the  other ;  these  currents  seem  to  me  as 
the  rule  to  pass  from  the  point,  when  they  reach  it,  down  to  the  centre  of 
the  spot  where  the  cilia  are  seen  terminating  the  endochrome." 

In  a  second  part  of  this  communication  the  writer  adds  :  "I  have  scarcely 
failed  in  one  attempt  to  see  the  circulation  and  cihaiy  motion  in  the  Clos- 
terium  Lunula.  I  tried  today  heating  a  little  water,  by  putting  a  small  bottle 
in  a  cup  of  warm  water ;  the  eifect  seemed  to  retard  the  circulation,  but  to 
make  the  globules  larger.  I  have  traced  it  over  the  whole  extent  of  the  en- 
dochrome, but  it  is  best  seen  at  the  convex  sid.e  a  short  way  from  the  edge.  I 
am  more  than  ever  convinced  the  cyclosis  is  the  waving  of  attached  tongues 
of  cilia.  The  specimens  are  capricious  in  the  results  they  afford  ;  they  show 
best  when  the  sun  has  been  on  the  jar  for  a  time,  I  have  watched  the  move- 
ments of  the  globules  in  Yallisneria,  Nifella,  &c.,  and  they  are  to  me  altogether 
of  a  different  natiu'e  to  that  in  the  Closterium^  &c.  To  my  eye  there  is  no 
real  analogy  between  this  circulation  and  that  in  the  above  plants  ;  but  there 
is  much  more  with  the  branchial  action  in  the  mussel."  Mr.  Jabez  Hogg's 
supplementary  notes  to  Mr.  Osborne's  paper  represent  the  whole  frond  as 
*'  brilliantly  glittering  with  the  moving  and  active  cilia ;  whilst  in  the 
cyclosis  numerous  zoospores  were  most  actively  moving  about  hj  the  same 
agency.  When  the  sunlight  falhng  on  these  httle  bodies  warmed  them  into 
life  and  motion,  the  rapid  undulations  produced  hj  the  action  of  the  cilia 
illuminated  the  whole  frond  with  a  series  of  most  channing  and  dehcately- 
coloured  prismatic  fringes  or  Newton's  rings.  The  motion  and  distribution 
of  the  cilia  must  be  seen  by  the  aid  of  the  direct  sun-rays  and  parabola  ;  for 
although  I  tried  every  other  mode  of  illumination,  and  with  Mr.  Brooke  used 
Gillett's  condenser,  yet  neither  of  us  noted  satisfactorily  their  situation  and 
distribution  until  we  resorted  to  the  parabola.  At  the  same  time  the  cir- 
culation may  be  most  accurately  obseiTed  to  take  place  over  the  entire 
surface  of  the  frond.  The  stream  is  best  seen  to  be  nmning  up  the  external 
margin,  just  internal  to  a  row  of  cilia,  with  another  taking  a  contrary  direc- 
tion next  to  the  serrated  ciliary  edge  of  the  endochi'ome ;  the  whole  being 
restricted  to  the  space  between  the  mass  of  endochrome  and  hyahne  integument 
passing  above  and  around  the  cyclosis,  but  not  entering  into  it." 

Another  wiiter  (J.  M.  S.  1855,  p.  84),  Mr.  Western,  adduces  an  observa- 
tion which  he  believes  to  confirm  the  presence  of  ciha  in  Closterium,  and 
even  goes  so  far  as  to  advance  the  notion  that  the  circulation  in  the  cells  of 
Chara,  and,  by  analogical  reasoning,  in  those  also  of  other  water-plants, 
originates  in  cihary  movements.  In  Chara,  as  in  Closterium,  he  tells  us,  he 
observed  "  precisely  the  same  appearances,  the  same  rapid  undulations,  to- 
gether with  the  same  brilliant  coruscations."  Dr.  Wright,  whose  contribu- 
tion in  the  same  Journal  (1855,  p.  171)  we  have  previously  quoted,  admits 
the  presence  of  cilia,  and  starts  the  extraordinaiy  supposition  that  the  circu- 
lation of  the  contents  of  Closterium  is  carried  on  through  canals  or  vessels, 
which  he  describes  as  marginal,  and  that  it  is  independent  "  of  a  frequent 
irregular  movement  of  granules  of  endochrome  more  resembhng  imperfect 
cyclosis." 

If  our  doctrines  concerning  the  physiology  of  animal  and  vegetable  cells  be 


OF  THE  DESMIDIE^.  9 

at  all  correct,  the  statements  above  quoted  respecting  the  ciliary  origin  of 
cyclosis,  and  more  particularly  the  hypothesis  of  a  vascular  system,  are 
scarcely  or  not  in  any  way  admissible.  We  are  disposed  to  attribute  the 
appearances  so  intei-preted  to  misconception.  Dr.  Wright's  notion  of  canals 
or  vessels  is  equally  extravagant  with  that  once  advanced  by  Schultze,  of  the 
network  of  sap-vessels  in  and  about  the  cells  of  plants,  and  requires  no  dis- 
cussion. The  opinion  of  Mr.  Osborne  that  the  ciuTcnts  in  Closteria  and  other 
Desmidieae  are  due  to  ciha,  and  are  not  analogous  ^dth  the  in  all  respects 
similar  currents  in  the  cells  of  various  aquatic  plants,  is  simply  an  assump- 
tion, and  one  indeed  in  opposition  both  to  what  an  unbiassed  observation  of 
the  phenomenon  in  the  two  sets  of  plants  would  suggest,  and  to  what  com-, 
parative  physiology  would  teach.  Again,  the  analogy  he  suggests  between 
his  supposed  ciliary  cyclosis  and  the  ciliaiy  action  of  the  branchiae  of  the 
mussel  will  be  inconceivable  to  any  one  who  understands  the  stnictiu'e  of  the 
branchial  apparatus  of  Mollusca,  the  distribution  of  the  cilia  on  the  external 
surface  of  a  mucous  membrane,  and  their  office  there  in  providing  for  the 
active  performance  of  the  respiratory  function.  Analogy  would,  indeed,  in- 
duce us  to  beheve,  that  if  cilia  are  the  motory  organs  of  the  cyclosis  of 
Desmidieae,  they  are  equally  so  of  that  in  other  unicellular  Alga3,  as  well  as 
of  that  in  the  cells  composing  the  tissue  of  compound  forms.  If  so,  we  might 
adopt  Mr.  Western's  belief  in  the  existence  of  ciha  wherever  a  cii'culation  of 
the  contents  of  cells  is  visible,  did  not  our  opinion  of  the  natm-e  of  cells  and 
of  the  histological  relations  of  their  parts  deter  us  from  accepting  the  doc- 
trine at  all  of  the  presence  of  internal  cilia  within  unicellular  organisms. 

Then,  again,  we  cannot  see  the  necessity  of  a  ciliary  apparatus  to  secure  the 
fluctuating,  oscillating  or  irregular  and  mostly  incomplete  movements  of  the 
corpuscles  within  the  cells  of  Desmidieae.  To  us  such  movements  are  expli- 
cable by  reference  to  the  changes  ensuing  in  the  nutritive  processes  of  the 
living  organism,  and  to  the  currents  caused  by  the  ever-acting  endosmose  and 
exosmose.  Moreover,  it  should  be  borne  in  mind  how  exceedingly  minute 
these  molecular  movements  are ;  how  very  inconsiderable  the  space  passed 
through  is  ;  how  sluggish,  compared  with  those  due  to  undoubted  ciliary  ac- 
tivity, the  movements  themselves  are.  But  in  addition  to  arguments  deducible 
from  analogy  and  general  morphology,  those  put  forward  by  Mr.  Wenham, 
resting  on  direct  observation  and  experiment,  seem  to  us  strongly  adverse  to 
Mr.  Osborne's  hypothesis,  and  indicate  it  to  be  a  consequence  of  optical  de- 
ception. At  a  preceding  page  (p.  5)  we  have  quoted  Mr.  Wenham's  remarks 
on  the  deceptive  effects  produced  in  viewing  objects  by  oblique  sunlight,  or 
by  any  powerful  source  of  illumination,  and  by  the  use  of  a  large  angle  of 
aperture ;  we  will  here  add  his  comparative  obseiTation  of  the  circulation  of 
Anacharis.  In  viewing  this,  he  tells  us  {op.  cit.  p.  159),  "  with  a  large  aper- 
ture, the  chlorophyU-granules  traversing  along  a  straight  and  thin  septum  (if 
the  position  is  favourable)  appear  to  project  into  the  neighbouring  cell,  seem- 
ing to  pass  directly  under  the  line  of  the  ceU-waU.  Smaller  particles  will 
apparently  travel  within  the  substance  of  the  cell-wall ;  and  in  case  of  a 
boundary  or  single  cell,  or  in  unicellular  plants,  if  the  surrounding  water  has 
nearly  dj'ied  up,  the  rim  or  prism  remaining  round  the  exterior  (by  the  way, 
just  the  conditions  under  which  Mr.  Western  made  his  obsel'^^ation)  causes 
irregular  refracted  images  of  the  particles  of  protoplasm  to  appear  outside  the 
cell,  bearing  such  a  remarkable  similarity  to  external  cilia,  that  the  passing 
shadows  may  even  be  mistaken  for  currents  in  the  water." 

Besides  the  incomplete  rotation  or  circulation  of  the  contents  just  con- 
sidered, there  is  an  active  bustling  sort  of  movement  of  minute  granules 
within  an  apparent  globular  Tesicle  situated  at  each  end  of  the  elongated 


10  GENEEAL  HISTORY  OF  THE  INFUSOEIA. 

fronds  of  some  Desmidiese,  e.g.  of  DocicUum  and  of  Closterium.  The  vesicles 
in  question  are  known  as  the  ''  terminal  globules,"  or  chambers,  and  would 
appear  to  be  actually  invested  with  a  membrane,  and  therefore  distinct  en- 
closed sacs.  In  Closterium  rostratum  and  C.  setaceum,  the  collection  of  moving 
granules  is  at  a  distance  from  the  extremities,  and  apparently  not  contained 
•within  a  vesicle.  In  all  species  exhibiting  terminal  globules  these  structures 
appear  in  their  earliest  stage,  but  disappear  when  they  are  dried. 

Ehrenberg  imagined  the  supposed  retractile  locomotive  organs  to  be  fixed 
to  these  globules,  and  that  the  granular  movement  within  them  was  no  other 
than  that  of  the  bases  of  these  organs.  Mr.  Varley  described  the  chambers 
as  having  contractile  walls,  and  the  molecules  as  transparent  spheroids  mea- 
suring from  l-20,000th  to  l-40,000th  of  an  inch,  sometimes  escaping  from 
their  chamber  and  circulating  vaguely  and  irregularly  between  the  periphery 
of  the  gelatinous  body  and  the  sheU,  Mr.  EaLfs  regarded  the  terminal  glo- 
bules to  be  pecuHar  to  the  Closterina ;  yet  their  contained  granules  seemed  to 
him  '^  to  differ  in  no  respect,  except  in  position  and  iminterrupted  motion, 
from  other  granules  in  the  same  frond."  He  once  saw  the  motion  continue 
after  their  escape  from  the  cell.  Mr.  Osborne  (oj>.  cit.  p.  235)  behoves  the 
granules  to  be  cihaiy  bodies.  He  writes :  "At  the  extremities  of  the  green 
matter  there  are  certain  bodies  acting  with  a  ciharj-  movement  within  what 
has  been  called  a  chamber,  lying  towards  the  point  of  the  membranous  sac ; 
certain  bodies,  apparently  of  the  same  kind,  separate  from  the  endochrome  in 
a  small  mass,  appearing  at  the  extreme  end  of  this  so-called  chamber,  or  at 
the  side  close  to  the  end ;  these  also  impart  a  ciliaiy  movement  to  the  water 
within  the  sac  around  them."  He  adds  (p.  239) :  "  When  the  endochrome 
is  of  a  rich  dark  green,  I  find  the  chamber  at  the  extremity  very  plain  and 
defined,  with  its  cilia  veiy  active ....  As  the  endochrome  gets  of  a  hghter 
colour. .  .  .the  chamber  becomes  smaller  and  the  ciha  are  barely  seen."  At 
p.  236,  Mr.  Osborne  fiu'ther  states,  "  The  loose  bodies  seen  in  the  chamber  of 
Closterium  Lunula  have  very  generally  cilia,  and  are,  I  behove,  zoospores ; 
loose  pieces  of  endochi^ome  are  sometimes  brought  round  in  the  current,  but 
these  are  easily  distinguished.  I  have  never  seen  anything  like  true  cyclosis, 
i.  e.  molecules  in  circular  movement,  within  the  so-called  chamber." 

Of  the  purpose  of  the  moving  granules  vrithin  the  tenninal  globules,  the 
prevaihng  notion  is  that  they  are  zoospores.  Meyen  hkened  them  to  the 
"  spennatic  animalcules  of  plants ;"  and,  as  above  noted,  Mr.  Ralfs  saw  them 
move  about  as  do  the  zoospores  of  other  Algae  when  freed  from  the  enclosing 
capsule  and  frond.  So  far  as  we  can  gather  from  his  remarks,  Mr.  Osborne 
also  inclines  to  this  opinion,  which  is  likewise  supported  by  Mrs.  Thomas 
(T.  M.  S.  1853,  p.  37). 

We  are  sony  that  we  can  present  no  more  definite  views  concerning  the 
nature,  characters,  and  purpose  of  the  terminal  globules  than  those  comprised 
in  the  foregoing  extracts.  We  find  no  similar  globules  in  other  Algae,  and 
therefore  obtain  no  guide  from  analogy ;  indeed  such  structures  seem  to  be 
peculiar  to  the  elongated  Desmidieae — to  the  genera  Closterium,  Penium,  and 
Docidium ;  we  must  consequently  look  to  subsequent  research  to  elucidate  the 
question.     (See  Appendix  at  end.) 

Another  sort  of  internal  movement,  more  prevalent  among  the  Desmidieae 
than  that  last  considered,  is  "  the  sivarming  motion"  so  called,  seen  either  at 
one  or  two  parts  of  the  frond  when  mature,  or  other^dse  throughout  its  con- 
tents. Having  once  commenced,  it  never  ceases,  but  extends  itself,  and 
induces  changes  in  the  nature,  appearance,  and  colour  of  the  endochi'ome ; 
for  this  loses  its  grass-green  colour,  acquires  the  autumnal  yellowish  or 
reddish-broTNTi  tint,  and  a  finely  granular  aspect.     When  the  granules  burst 


OF  THE  DESMIDIE^.  11 

through  the  openings  of  the  suture  between  the  valves,  they  escape  to  a 
distance  and  still  keep  up  their  active  movement. 

In  the  genus  Cosmarium  this  phenomenon  is  frequently  and  readily  ob- 
served. Mrs.  Thomas,  in  her  interesting  obser\-ations  on  Cosmarium  mar- 
garitiferum  (T.  M.  S.  1855,  p.  33),  has  detailed  the  following  appearances : — 
"  In  each  half  (she  wiites)  the  centre  was  occupied  by  a  vesicle  (as  it  appeared) 
filled  with  moving  granules,  while  smaller  vesicles  were  at  the  four  sides 
(I.  2).  The  granules  did  not  appear  to  circulate  through  the  plant,  but  kept 
to  their  own  place,  which  was  either  a  bag  or  cavity — I  could  not  decide 
which."  In  another  example  "  the  granules  were  swanning  over  the  whole 
plant." 

These  peculiar  movements  of  the  granhles  are  not  restricted  to  this  tribe, 
but  are  known  to  occur  in  many  genera  of  Algae.  Their  piu'pose  seems  con- 
nected with  the  reproductive  process.  Mrs.  Thomas  {he.  cit.)  refers  to  it  as 
in  some  way  related  with  the  formation  of  sporangia ;  whilst  Mr.  Ralfs,  who 
speaks  of  the  swarming  particles  as  "  zoospores,"  confesses  himself  perfectly 
unacquainted  with  theii'  subsequent  histoiy,  although  he  coincides  with  Pro- 
fessor Harvey  in  regarding  the  phenomenon  of  swarming  as  a  "  strictly  vege- 
table pecuharity." 

Eepeoduction  of  Desmtdie^. — This  function  presents  itself  under  two 
phases,  the  end  of  one  of  which  is  to  multiply  or  perpetuate  the  individual 
plant,  whilst  that  of  the  other  is  to  reproduce  the  species.  The  fonner  pur- 
pose is  attained  by  the  process  of  fission,  the  latter  by  that  of  the  development 
of  sporangia,  and,  it  may  be,  by  the  swarming  of  zoospores. 

The  act  of  self-division  is  frequently  observed,  and  is  in  all  respects  the 
same  process  as  in  the  cells  of  other  Algae,  or  indeed  of  any  plant.  Analogy, 
and  not,  indeed,  dii-ect  obsei-vation,  suggests  as  necessary  the  initiative  action 
of  a  nucleus  to  precede  the  constriction  of  the  soft  lining  sac  of  the  lorica, 
i.  e.  of  the  primordial  membrane,  which  is  next  followed  by  that  of  the  harder 
external  coat.  The  proceeding  is  varied,  in  some  non-essential  particulars,  by 
the  figiu'e  of  the  fronds,  and  also  by  the  cii'cumstance  of  its  own  completeness 
or  incompleteness.  !Mr.  Ralfs  has  well  described  the  fission  of  Euastrmn  (op. 
cit.  p.  4).  The  narrow  connecting  band  between  the  two  segments  of  the 
frond  lengthens  and  is  "  converted  into  two  roundish  hyaline  lobules ; "  these, 
though  at  first  veiy  minute,  increase  rapidly  in  size,  and  exhibit  from  their 
origin  the  deep  constriction  characteristic  of  the  mature  fronds.  The  advancing 
growth  of  the  interposed  new  fonnations  necessarily  pushes  fiu'ther  asunder  the 
original  segments,  which  finally  become  disconnected,  "  each  taking  with  it  a 
new  segment  to  supply  the  place  of  that  from  which  it  has  separated ....  At 
first  the  new  portions  are  devoid  of  colour,  and  have  much  the  appearance  of 
condensed  gelatine ;  but  as  they  increase  in  size  the  internal  fluid  acquires  a 
green  tint,  which  is  at  fii^st  very  faint,  but  soon  becomes  darker ;  at  length 
it  assumes  a  granular  state.  At  the  same  time  the  new  segments  increase 
in  size  and  obtain  their  noiTaal  figui'e ;  the  covering  in  some  species  shows 
the  presence  of  puncta  or  granules,  and,  as  in  Xanthidium  and  Staurastrumj 
the  spines  and  processes  lastly  make  their  appearance,  beginning  as  mere 
tubercles,  and  then  lengthening  until  they  attain  their  perfect  fonn  and  size. 
Complete  separation,  however,  often  occiu's  before  all  these  details  of  develop- 
ment are  complete  (II.  11,  24,  26).  This  singular  process  is  repeated  again 
and  again,  so  that  the  older  segments  are  united  successively,  as  it  were,  with 
many  generations."  Illustrations  of  this  act  are  fiu-nished,  in  the  case  of  two 
species  of  Cosmarium,  in  the  appended  jDlates  (I.  4 ;  II.  26),  to  which  the 
above  account  will  be  found  equally  well  to  apply. 

^•In  Sphcerozosma  the  same  changes  take  place  (I.  11),  and  are  just  as 


12  GENERAL  HISTOEY  OF  THE  INEUSOlilA. 

evident;  but  the  cells  continue  linked  together,  and  a  filament  is  formed,  which 
elongates  more  and  more  rapidly  as  the  joints  increase  in  mmiber.  This 
continued  miiltif)lication  by  division  has  its  limits ;  the  segments  gradually 
enlarge  whilst  they  divide,  and  at  length  the  plant  ceases  to  grow;  the  division 
of  the  cells  is  no  longer  repeated ;  the  internal  matter  changes  its  appearance, 
increases  in  density  and  acquires  starch-granules,  which  soon  become  nume- 
rous ;  the  reproductive  gi*anules  are  perfected,  and  the  individual  perishes. 
In  a  filament  the  two  oldest  segments  are  found  at  its  opposite  extremities ; 
for  so  long  as  the  joints  divide,  they  are  necessarily  separated  further  and 
further  from  each  other.  Whilst  tins  process  is  in  progress,  the  filament  in 
Sjohcerozosma  consists  of  segments  of  all  sizes  (1. 11) ;  but  after  it  has  reached 
matuiity  there  is  httle  inequahty  between  them,  except  in  some  of  the  last- 
formed  segments,  which  are  permanently  smaller.  The  case  is  the  same  with 
those  genera  in  which  the  separation  of  the  cells  is  complete ....  It  is  obvious 
that  the  new  portions  must  arise  from  the  whole  of  the  junction-margin  of 
the  original  valves ;  consequently  when  the  junction  occupies  only  a  part  of 
the  breadth,  the  new  portion  will  be  naiTower  than  the  old ;  but  when  the 
junction  of  the  valves  is  as  broad  as  the  cell,  the  new  poiiion  will  from  the 
beginning  be  of  the  same  breadth,"  and  will  remain  undistinguishable  by  its 
size  when  fission  is  complete. 

Mr.  Balfs  goes  on  to  say  that,  "  when  the  ceU  is  oblong,  or  only  rounded 
at  the  extremities,  the  process,  though  similar,  is  less  evident ;  the  cell  at 
first  seems  merely  to  elongate  (II.  11),  until  it  attains  nearly  twice  its  ori- 
ginal length,  when  the  division  commences,  and  the  rounding  of  the  new  ends 
becomes  apparent.  The  tapering  cells  present  but  little  diiference,  for  the 
separation  takes  place  before  the  extremities  are  fully  developed ;  sometimes 
these  cells  separate  obhquely,  as  in  Sjpirotce7iia.'^ 

The  mode  of  self-division  in  Closterium  has  been  illustrated  by  the  Rev. 
Mr.  Osborne  (J.  M.  8.  1854,  p.  57),  from  whose  account  we  abstract  the  fol- 
lowing particulars : — '^  I  have  (he  says)  watched  for  hours  the  process  of 
complete  self-division ;  one-half  of  the  frond  has  remained  passive,  the  other 
has  had  a  motion  from  side  to  side,  as  if  moving  on  an  axis  at  the  point  of 
juncture ;  the  separation  has  become  more  and  more  ardent,  the  motion  more 
active,  until  at  last,  with  a  jerk,  one  segment  leaves  the  other,"  each  having 
one  extremity — the  one  newly  formed  along  the  line  of  junction  of  the  two 
segments — much  more  obtuse  than  the  other.  '^  The  circulation  of  the  con- 
tained globules  for  some  hours  previons  to  subdivision,  and  for  some  few  hours 
afterwards,  runs  quite  round  the  obtuse  end  of  the  endochrome." 

Previously  to  complete  separation  each  segment  begins  to  show  a  central 
constriction  of  its  endochrome,  which  in  due  time  extends  across  the  new 
frond,  and  constitutes  the  median  clear  space  or  band. 

A  true  reproductive  act  is  presented  by  the  act  of  conjugation,  or  coupling 
of  two  fronds,  and  by  the  resultant  development  of  a  sporangium  (II.  6,  8 ; 
XYI.  11, 12, 13, 14).  This  process  consists  in  the  apposition  and  subsequent 
intercommunication  of  the  cavities  and  contents  of  two  cells,  which  may  be 
free,  or  otherwise,  members  of  a  chain  or  filament.  It  is  an  act  not  peculiar 
to  the  Desmidieae,  but  common  to  them  along  with  the  Diatomeae  and  Con- 
jugat£e.  "  In  the  family  Conjugatae  (says  Mr.  Ralfs)  the  cells  conjugate 
whilst  still  forming  parts  of  a  fidament ;  but  in  the  Desmidiese  the  filamentous 
species  almost  invariably  separate  into  single  joints  before  their  conjugation, 
and  in  most  of  the  species  the  valves  of  the  cells  become  detached  after  they 
are  emptied  of  their  contents."  To  bring  about  the  necessary  apposition,  it 
is  usual  for  the  conjugating  cells  to  expand  or  bulge  out  on  those  sides  which 
are  to  come  into  union ;  and  whilst  this  is  proceeding,  the  vesicles  or  globules 


OF  THE  DESMIDIEiE.  13 

increase  much  in  number,  and,  together  with  the  granular  contents,  become 
aggregated  about  the  conjugating  part.  When  contact  is  complete,  an  absorp- 
tion of  the  opposed  walls  of  the  two  cells  takes  place,  or  the  suture  of  each 
opens,  the  endochrome  from  both  is  discharged  and  intermingled,  and  an 
orbicular  green  granular  mass,  enveloped  in  a  mucous  sheath  thrown  out 
around  it  by  the  conjugating  cells,  is  produced.  When  the  process  has  pro- 
ceeded thus  far,  the  original  valves  are  more  or  less  completely  emptied  of 
theii'  contents,  lose  their  vitality,  and  are  sooner  or  later  detached,  and  float 
away  from  the  sporangium  developed. 

The  foi-mation  of  a  sporangium  by  conjugation  occupies  no  great  time. 
Indeed,  in  the  case  of  Closterium  Ehreyibergii,  the  Eev.  W.  Smith  tells  us 
that  "  the  discharge  of  the  endochrome  and  the  fomiation  of  the  sporangia 
are  accomplished  with  much  rapidity,  and  may  often  be  seen  taking  place  in 
the  field  of  the  microscope ;  the  whole  operation  not  occupying  more  than 
a  few  minutes ....  During  the  formation  of  the  sporangia  there  appears  to 
be  a  second  development  of  mucus  in  the  form  of  rings  around  the  reproduc- 
tive bodies  ;  this  is  probably  only  the  eftect  of  the  pressure  produced  by  the 
growth  of  the  sporangia  on  the  mass  of  investing  mucus." 

This  act  of  conjugation  admits  of  slight  variations  in  character,  determined 
by  the  form  of  the  conjugating  cells,  and  by  other  circumstances  pecuhar  to 
the  tribe,  family,  or  genus  in  which  in  it  occurs.  In  the  filamentous  species 
of  Desmidieae,  the  joints,  as  before  noted,  usually  become  separated  before 
their  conjugation ;  and  in  most  instances  the  old  valves  left  empty  after  the 
act  of  conjugation  are  almost  immediately  detached  from  the  sporangium ; 
but  in  a  few  species  they  persist  some  time  afterwards,  e.  g.  in  several  of 
Penium.  In  Didymoprium  the  separated  joints,  on  conjugating,  unite  by 
means  of  a  narrow  process  pushed  out  from  each,  and  often  of  considerable 
length ;  through  this  the  endochrome  of  one  cell  is  transferred  into  the  other, 
and  thus  the  spoi-angium  is  produced  within  one  of  the  two  cells,  just  as  in 
the  Conjugatae.  In  Staurastrimi  and  Micrasterias  the  contents  of  both 
fronds  are  discharged  into  a  delicate  intermediate  sac  or  bag,  which  gradually 
thickens,  produces  eminences,  and  at  last  forked  spines  (II.  25).  Again,  in 
Tetmemorus,  "  the  process  of  foiming  the  sporangium  (says  Mr.  Ealfs)  is 
interesting,  as  it  exhibits  a  striking  similarity  to  the  change  during  the 
formation  of  similar  bodies  in  Stcmrocarpus  among  the  Conjugatae.  In 
Staurocarpus,  after  conjugation,  a  subquadrate  ceU  is  formed,  within  which 
the  endochrome  is  collected.  The  latter  is  at  fii'st  of  the  same  figure  as  the 
ceU,  but  in  at  least  one  species  is  at  length  condensed  into  a  compact 
globular  body,  and  in  every  species  the  cell  with  the  contained  sporangium 
finally  separates  from  the  filaments  with  which  it  is  connected.  In  this 
separate  state  I  can  discover  no  character  by  which  to  distinguish  the 
sporangium  of  Tetmemorus  from  one  belonging  to  a  species  of  Staurocarpus.''^ 
To  quote  the  same  authority, — ^^In  Penium  Jenneri  the  conjugating  fronds  do 
not  open  and  gape  at  the  suture,  as  is  usual  in  the  Desmidieae,  but  couple  by 

small  and  distinct  cylindrical  tubes  like  many  of  the  Conjugatae In 

Closterium  two  fronds  unite  by  means  of  projections  arising  at  the  junction  of 
the  two  segments,  and  then  the  newly-formed  portion  continues  to  enlarge 
until  the  original  segments  are  separated  by  a  cell  of  an  irregular  figure  (II. 
5,  6).  The  contents  of  the  fronds  being  collected  in  this  cell  become  a  dense 
seed-like  mass,  which  is  sometimes  globular,  resembhng  the  sporangium  of 
Mougeotia,  and  sometimes  square,  like  that  of  Staurospermum.  The  newly- 
formed  cell  is  thinner  and  generally  paler  than  the  segments  of  the  fronds ; 
in  some  species  it  looks  like  a  prolongation  of  the  segments,  and  in  others 
these  are  so  loosely  attached  that  their  connexion  is  scarcely  perceptible. 


14  GENERAL  HISTOEY  OF  THE  INFUSORIA. 

The  coupling  of  the  fronds  generally  takes  place  from  the  convex  margin, 
but  may  occur  on  the  concave,  or  even  the  convex  margin  of  one  frond  may 
couple  with  the  concave  of  the  other." 

The  Rev.  W.  Smith  (A.  N.  H.  1850)  represents  the  conjugation  of 
Closterium  Ehrenhergii  to  be  peculiar  (XYI.  11,  12,  13,  14).  The  fii'st 
phenomenon  (he  tells  us)  is  an  alteration  in  the  granular  condition  of  the 
endochrome.  This,  from  a  light  yellowish  green,  passes  to  a  much  darker 
shade,  and  the  larger  granules,  or  ''  diaphanous  vesicles "  of  Ealfs,  which 
were  originally  few  in  number,  and  arranged  in  a  somewhat  irregular  longi- 
tudinal series  (XVI.  10),  become  exceedingly  numerous  and  pervade  the 
entire  frond.  While  this  change  is  about  taking  place,  the  fronds  approach 
in  pairs,  approximating  by  their  concave  surfaces,  and  finally  coming  into 
such  close  neighbourhood  that  their  inflated  centres  are  in  contact  and  their 
extremities  slightly  overlapped  (XYI.  11).  In  a  short  time,  probably  in  the 
course  of  twenty-four  hours,  a  remarkable  change  takes  place,  both  in  the 
appearance  and  condition  of  the  fronds  ;  a  mass  of  delicate  mucus  is  secreted 
around  the  approximated  fronds ;  these  remove  to  a  little  distance  from  each 
other,  undergo  "  self -division,"  and  present  altogether  an  irregular  oval  figiire, 
the  outline  of  which  is  formed  by  the  periphery  of  the  mucus,  the  four  divi- 
sions of  the  fronds  being  placed  in  the  middle  in  a  somewhat  quadi'ilateral 
manner  (XYI.  12).  Duiing  the  progress  of  cell-division,  the  internal  mem- 
brane of  the  cell-wall  becomes  enlarged  at  the  suture  or  line  of  separation, 
and  projects  in  the  form  of  an  irregular  cone,  with  a  blunt  or  rounded  apex 
forming  a  beak,  whose  side  view  presents  a  triangular  outhne.  This  beak 
becomes  fiUed  with  endochrome,  either  by  the  dilatation  or  increase  of  the 
contents  of  the  half-frond,  and  the  divided  frond  assimies  the  appearance  of 
one  with  two  unequal  segments  (12),  being  what  M.  Morren  calls  ''  a  Clos- 
terium of  two  unequal  cones."  On  these  membranous  expansions,  at  the  con- 
cave sui-faces  of  the  fronds,  and  close  to  the  original  sutm-es,  there  appear, 
almost  simultaneously  with  the  fonuation  of  the  beaks,  two  cii'cular  projec- 
tions, which,  rupturing  at  their  apices,  give  egress  to  the  delicate  sacs  which 
enclose  the  endochrome,  and  which,  drawing  with  them  their  contents,  and 
meeting  with  the  endochrome  sacs  emitted  through  similar  projections  from 
the  other  half-fronds,  form,  by  their  connexion,  irregular  masses,  which 
quickly  consolidate  and  assume  the  appearance  of  perfectly  circular,  smooth, 
dark-coloui'ed  baUs,  the  sporangia  of  Ralfs  and  seminules  of  Morren. 

Lastly,  we  may  add,  that  Siebold  {J.  M.  S.  1853,  pp.  118, 119)  remarks  that 
the  conjugation  in  Closterium  Diance,  C.  lineatum,  C.  striolatum,  C.  setaceum, 
&c.,  differs  from  that  in  C.  Lunula,  G.  rostratum,  and  other  members  of  the 
family,  by  dehiscence  at  the  central  transverse  suture,  and  the  consequent 
coalescence  of  the  contents  of  the  two  cells  into  a  rounded  or  angular  mass, — 
an  observation  which  tallies  with  the  account  presented  us  by  Mr.  Ealfs. 

Braun  (On  Rejuvenescence,  B.  S.  p.  286  et  seq.),  speaking  of  conjugation 
generally  in  simple  cells,  gives  an  elaborate  view  of  the  Variations  the  phe- 
nomenon exhibits,  and  arranges  them  under  several  heads.  Thus  among  the 
Desmidiese  "  the  conjugating  cells  unite  with  participation  of  the  external 
membrane,  [and]  the  reproductive  cell  is  formed  [either]  through  contraction 
of  the  contents  clothed  by  the  internal  cell-membrane,  [or]  out  of  the  mere 
contents  as  a  new  cell  inside  the  mother- ceU."  But  in  the  majority  of  the 
Desmidieae,  "  the  conjugating  cells,  after  dehiscence  of  the  outer  membrane, 
unite  through  the  inner ;  the  reproductive  ceU  is  formed  out  of  the  mere 
contents  as  a  new  cell  inside  the  conjugation-cell."  By  the  first-named 
mode,  "  the  formation  of  the  reproductive  cell  is  ...  .  not  a  direct  result  of 
the  conjugation,  but  it  is  formed  subsequently  in  the  interior  of  the  con- 


OF  THE  DESMIDIE^.  '  15 

jugation-cell,  in  the  strongly  expanded  isthmus  of  this.  The  delicate  internal 
membrane,  mth  the  contents  enclosed  by  it,  draT\ang  itself  out  of  the  extre- 
mities of  the  double  cell,  forms  a  seed- cell,  at  first  cniciate,  four-lobed,  then 
bluntly  quadi^angular,  and  finally  globular,  clothed  by  a  many-layered 
thickened  membrane  "within  the  persistent  four-horned  conjugation-cell. 
From  Ralfs's  representation,  this  is  most  probably  the  way  in  which  the  pro- 
cess is  to  be  understood  in  Cylindrocystis  (Penium)  Brehissonii.''^ 

The  second  mode,  when  the  union  of  the  isolated  cells  is  also  lateral  and 
parallel,  is  exemplified  in  CJosterium  Lunula,  in  which,  according  to  Morren's 
express  statement,  thi-ee  different  membranes  take  part  in  ^  the  formation  of 
the  canal  of  union, — an  inner  and  an  outer  cell-membrane,  and  a  membrane 
(the  primordial  utricle)  immediately  enclosing  the  green  mass.  The  glo- 
bular reproductive  cell  formed  in  the  connecting  canal  is  an  active  gonidium, 
which  begins  to  revolve  even  while  in  the  canal,  and  soon  breaks  through  the 
gelatinously-swollen  membrane  of  the  latter.  Very  often  two  approximated 
individuals  divide  again  and  conjugate  before  they  have  completely  separated, 
whence  result  conjugated  double  pairs. 

The  third  scheme  of  conjugation,  the  most  widely  extended,  is  itself 
reduced  by  Braun  to  two  principal  secondaiy  varieties,  and  to  several  sub- 
sidiary ones.  Thus  conjugation  takes  place  either  in  a  parallel  position  or  in 
a  crossed  (decussate)  manner.  The  former  is  peculiar  to  the  Closterina ;  the 
latter  is  met  with  in  Euastrum  and  allied  forms,  and  also  in  many  genera 
formerly  united  with  Desmidium.  The  modifications,  in  various  species,  of 
these  plans  are  well  explained  in  Braun's  work,  to  which  we  would  refer 
for  particulars,  as  well  as  for  an  elucidation  of  the  production  of  a  "  really 
double  spore  (not  two-lobed,  as  Ealfs  terms  it)  "  in  Closterium  lineatum. 

The  next  question  which  presents  itself  is,  whether  the  product  of  con- 
jugation is  to  be  esteemed  a  spore  or  a  spore-case,  i.  e.  a  sporanyium.  That 
the  latter  is  its  natiu-e  appears  pretty  clear,  and  is  assumed  as  a  fact  by  Mr. 
Ralfs.  This  authority  observes:  "The  sporangia  I  consider  capsules,  and 
this  view  seems  to  be  confirmed  by  the  experience  of  Mr.  Jenner,  who  states 
that  the  coveiing  of  the  sporangium  swells,  and  a  mucus  is  secreted,  in 
which  minute  fronds  ai)pear,  and  by  their  increase  at  length  rupture  the 
attenuated  covering."  In  this  opinion  Siebold  coincides ;  and  the  Rev.  W, 
Smith  {A.  N.  H.  1850,  p.  4)  represents,  on  the  authority  of  Mr.  Jenner,  the 
biu-sting  of  a  sporangium  of  Closterium  acerosum,  and  the  development  of 
young  fronds  from  its  contents. 

Braun,  in  his  philosophical  treatise  (oj).  cit.  B.  S.  p.  133),  remarks  of  the 
products  of  conjugation  in  the  Desmidieae,  that  "  they  do  not  pass,  Hke  the 
swarming-cells  of  the  PalmeUaceae  and  the  reproductive  cells  of  the  Dia- 
tomaceae,  directly  and  by  uninterrupted  growth  into  the  primaiy  generation 
of  the  new  vegetative  series,  but  persist  for  a  long  time  in  a  condition  of  rest, 
during  Avhich,  excepting  as  regards  imperceptible  internal  processes,  they 
remain  wholly  unchanged.  To  distinguish  these  from  the  direct  germ- cells 
(gonidia),  I  shaU  call  them  seed-cells  (spores).  The  development  of  these 
spores  has  not  yet  been  observed ;  but  it  may  be  assumed  as  certain,  that 
they  do  not  pass  as  such  into  the  primary  generation,  but  produce  this  at  the 
period  of  germination,  by  an  internal  transformation  of  their  contents,  and 
bring  these  to  light  as  a  new  generation  with  a  dehiscence  of  the  old  en- 
velope. Certain  early  conditions  observed  in  Closterium  and  Euastrum,  namely 
fanuhes  of  unusually  small  individuals,  enclosed  in  transparent  colourless 
vesicles,  render  it  even  probable  that  in  certain  genera  of  Desmidie«,  a 
number  of  individuals  are  produced  from  one  spore,  by  a  formation  of  transi- 
toiy  generations  occiUTing  already  within  the  spore.     The  enclosing  vesicle 


16  GENERAL  HISTORY  OF  THE  INFUSORIA. 

is  probably  the  dissolved  and  swollen-iip  internal  cell-coat  of  the  spore, 
which  holds  the  young  individuals  combined  for  some  time  after  the  outer 
coat  of  the  spore  has  been  throvrn  off." 

Although  Braun  has,  in  the  preceding  account, made  use  of  the  teiTn  ''spore'* 
to  express  the  conjugation-product,  yet,  in  the  veiy  admission  that,  in  those 
Desmidieae  in  which  only  we  have  any  clue  to  the  subsequent  history,  it 
produces,  not  a  single  indi\idual,  as  does  a  spore  commonly  so  called,  but  a 
multitude,  he  essentially  agrees  with  Mr.  Ralfs,  who  prefers  to  call  the  body 
a  capsule.  We  may  quote  Mrs.  Thomas  in  support  of  the  same  view ;  for  she 
considers  the  s]X)rangium  a  capsule,  or  {T.  M.  S.  1855,  pp.  36,  37)  "  the 
winter  casing  of  a  large  nimiber  of  j^oung  plants  which  escape  fi'om  it  by 
rapidly  knocking  against  its  walls,  when  these  have  been  loosened  by  spring- 
warmth,  or  which  grow  up  as  the  waUs  gradually  decay  in  the  midst  of  slimy 
gelatinous  masses."  In  proof  of  this  oj)inion  this  lady  appeals  to  the  immense 
increase  in  the  number  of  plants  seen  in  the  spring  beyond  what  can  be  ex- 
plained as  the  result  of  self-fission. 

In  her  opinion  the  sporangium  is  a  capsule  (I.  8,  9)  filled  with  zoospores 
similar  to  those  moving  granules,  supposed  to  be  such,  seen  mthin  the  fuU- 
grown  plant,  capable,  when  their  fitting  time  comes,  of  filling  the  waters 
with  their  countless  progeny. 

In  these  accounts  there  is  a  pervading  harmony ;  and  the  truth  seems  to 
be  that,  by  the  formation  of  a  sporangium,  provision  is  made  for  the  per- 
petuation of  the  species  through  the  "wdnter,  when  the  large  majority,  at 
least  of  adult  plants,  have  ceased  to  exist.  The  phenomenon  is  clearly 
analogous  to  that  of  the  foimation  of  seeds  by  herbaceous  plants,  or  of  ova 
by  insects  and  other  animals,  when  the  cycle  of  existence  of  the  parent  being 
is  complete,  or  is  put  an  end  to  by  unfavoiu-able  external  circumstances. 

Braun  has  expressed  the  sequence  in  the  phases  of  existence  in  the  follow- 
ing technical  language  {R.S.  p.  133):  ''  In  the  Desmidiaceae,  the  Zygnemaceae, 
and  in  Pahnoglcea,  the  transitional  generation  is  divided  into  a  double  one, 
since  the  last  generation  does  not  pass  directly  into  the  fii^st,  but  the  first 
generation  of  the  succeeding  cycle  is  produced  as  a  new  structure  in  the  ger- 
mination ;  so  that  we  have  here  to  distinguish  three  kinds  of  generation  of 
cells, — the  commencing  generation,  the  concluding  generation,  and  the 
intermediate  vegetative  generations."  The  last-named  is  represented  by  the 
process  of  self-fission,  which  takes  place  in  the  perfect  plant,  and  is  con- 
tinued through  a  long  series  of  individuals. 

Between  its  firet  appearance  and  its  ultimate  development,  the  sporangium 
of  Desmidieae  undergoes  a  progressive  series  of  changes ;  at  first  it  is  pale 
and  homogeneous,  but  soon  gets  granular,  acquires  a  gradually  deepening 
green  colour,  and  presents  vesicles  and  globules  in  large  number.  The  enve- 
lope, at  first  very  dehcate,  augments  in  thickness,  and  becomes  lined  by 
others,  whilst  its  surface  either  remains  smooth  or  becomes  granular,  tuber- 
culated,  or  spinous,  and  the  spines  themselves  in  many  instances  forked  or 
branched  (II.  15,  22,  25,  30,  34).  Simultaneously  with  these  changes  the 
integument  increases  in  density,  and  together  with  its  processes  acquires 
considerable  firmness  and  toughness.  Moreover,  as  it  advances  in  age  it 
usually  assumes  a  reddish-brown  colour;  when  this  has  happened,  the 
sporangium  and  contents  may  be  presumed  to  have  reached  maturity. 

Mrs.  Thomas  (op.  cit.  p.  35)  thinks  she  encountered  a  mature  sporangium 
of  Cosinarium  margaritiferum  in  the  shape  of  a  many- coated  ball  filled  with 
granules  in  the  same  rapid  motion  as  observed  in  the  full-grown  Cosmarium 
(I.  10,  11).  "  The  similarity  of  the  movement  (she  says)  attracted  my 
attention;  and  I  also  saw  that  in  one  part  the  enclosing  membrane  appeared 


OF  THE  DESMIDIE^.  17 

thinner,  as  if  giving  way  at  that  spot.  On  the  third  morning  the  membrane 
had  broken  and  the  granules  escaped,  leaving  the  nearly  emptied  case" 
(I.  12). 

Inasmuch  as  a  sporangium  may  pass  successively  from  a  smooth  to  a  spinous 
condition,  it  follows  that  the  transitional  stages  of  one  species  may  be  mistaken 
for  the  final  stage  of  another ;  hence  a  difiiculty  in  determining  to  what  plant 
detached  scattered  sporangia  may  belong.  It  is  only,  indeed,  when  these  seed- 
capsules  occur  in  company  with  the  fronds  producing  them  that  we  are  enabled 
to  pronounce  decisively  by  what  species  they  are  generated. 

As  the  foregoing  account  of  conjugation  and  sporangia  passed  through  the 
press,  we  met  Tvdth  the  valuable  paper  of  Dr.  Hofmeister  on  the  propagation 
of  the  Desmidieee  and  Diatomeae,  translated  by  Prof.  Henfrey  from  the 
Report  of  the  Natural  History  Society  of  Saxony  for  1857.  This  commu- 
nication tends  to  clear  up  the  questions  of  the  nature  of  the  sporangia  and  of 
the  relation  of  theii'  contents  to  the  propagative  process.  The  conciseness  of 
the  description  renders  abridgment  undesirable ;  and  we  accordingly  present 
it  (so  far  as  it  relates  to  the  points  in  question)  as  it  stands  in  the  Annals  of 
Natural  History  (1858,  i.  p.  2)  :— 

"  The  conjugated  indi\iduals  of  Cosmariwn  tetraojjhthahmm  displayed 
exactly  the  behavioui*  which  Kalfs  has  represented  and  Braim  described  of 
those  of  Cosmarium  margaritiferum.  The  Cosmrtr/a  which  had  commenced 
the  conjugation  process  appeared  cracked  apart  at  the  constricted  place  in  the 
middle.  Into  each  of  the  halves  of  the  tuberculated  cell- coat  of  the  two 
mother-indi\'iduals  extended  a  continuation  of  the  membrane  of  the  conju- 
gation-ceU.  This  smooth  membrane  completely  lined  the  interior  of  the 
tuberculated  half-shells.  The  contents  of  the  conjugation -cell  revealed  no 
definite  arrangement ;  they  were  mostly  accumulated  in  the  middle  into  an 
irregularly-shaped  ball ;  in  other  cases  separated  into  several  such  balls,  part 
of  which  extended  even  into  the  split  haK-sheUs  of  the  mother-cell.  With 
these  conjugated  individuals,  in  the  same  fiuid,  occuiTed  (very  sparingly)  par- 
ticular specimens  which  bore,  in  the  middle  space  between  the  two  separated 
half- shells,  a  broad,  delicate- walled  utricle,  the  circumference  of  which  about 
equalled  that  of  the  two  half-ceUs  taken  together.  The  arrangement  of  the 
cell- contents  in  the  primary  portions  of  the  cell  did  not  appear  essentially 
altered ;  the  contents  of  the  intermediate  expansion  consisted  of  a  thick  coat 
upon  the  wall  of  granular  protoplasm  "svith  sparingly-scattered  chlorophyll. 
This  condition  is  probably  that  which  immediately  precedes  conjugation, 
originating  by  excretion  of  new  cellulose  at  the  deepest  part  of  the  constric- 
tion, after  the  cracking  of  the  membrane  and  separation  of  the  primary  halves 
of  the  cell,  exactly  as  in  normal  cell- division,  from  which  this  process  can 
only  be  distinguished  by  the  omission  of  the  formation  of  a  septum  at  the 
narrowest  part  of  the  isthmus.  Similar  phenomena  have  been  observed  by 
Niigeli  in  Cosmarium  crenulatum,  and  by  Mrs.  Herbert  Thomas  in  Cosmarium 
margaritiferum  (scarcely  specifically  distinct  from  C.  tetraophthalmimi),  only 
that  here  the  intermediate  piece  of  the  Alga  did  not  conjugate  with  the 
similar  piece  of  another  individual,  but,  producing  tubercles  on  its  outer 
surface,  continued  the  vegetative  life. 

"  In  other  conjugation-cells  there  lay,  in  the  middle  part  of  the  conjugation- 
cell,  a  globular  ceU  enveloped  in  a  rather  thick  membrane,  of  gelatinous 
aspect,  and  smooth  on  the  outside  (the  spore).  No  intermediate  stages  could 
be  found  between  this  and  the  previously- described  condition.  Experiments, 
in  which  an  attempt  was  made  to  obtain  a  completion  of-  the  less-advanced 
conjugation  under  the  microscope,  all  failed.  Apparently  the  conjugation- 
ceU  is  exceedingly  sensitive  to  any  external  injury,  especially  to  contact  with 


18  GENERAL  HISTORY  OF  THE  INFUSORIA. 

foreign  bodies.     Very  probably  the  contents,  in  the  above-described  cases, 
were  ali'eady  abnormally  altered,  and  incapable  of  further  development. 

*'  In  other  conjugation- cells  the  young  spore  displayed  a  still  thicker  mem- 
brane, covered  on  the  outside  with  tiimcate- conical  elevations,  in  which 
membrane  could  be  detected  a  composition  of  two  colourless  layers.  The 
outer  of  these  layers  remained  clear  and  transparent  even  in  the  advance  to 
maturity.  Its  elevations  became  developed  into  rather  long  spines,  which 
forked  at  the  apices  into  two  or  four  branches.  The  deeper- seated  layer  of 
the  spore-membrane  meanwhile  assumed  a  dark-brown  colour.  By  rolling 
under  the  covering-glass,  the  tough,  colomiess,  outer  layer  may  be  readily 
stripped  from  the  inner,  more  brittle,  brown  layer ;  then  the  latter  appears 
covered  on  its  outer  surface  with  slight  elevations,  similar  to  those  which 
first  appeared  upon  the  yoimg  spore.  The  brown  layer  of  the  spore-coat 
encloses  a  thii'd,  delicate,  coloiuiess  layer  (perhaps  the  primary  membrane 
of  the  spore)  which  immediately  envelopes  the  cell-contents. 

*'  At  the  beginning  of  July,  the  green  contents  of  all  the  spores  appeared 
conglobated  into  a  spherical  mass  with  sharp  outlines,  which,  lying  free  in 
the  middle  part  of  the  cell,  nowhere  touched  its  internal  Avail.  Three  weeks 
later,  in  many  of  the  spores  these  contents  appeared  separated  into  two 
flattened  ellipsoidal  masses;  when  I  cracked  the  cell  by  careful  pressui^e, 
I  was  sometimes  successful  in  diiving  out  one  or  both  of  the  masses  of 
contents  in  an  uninjured  condition.  They  could  then  be  recognized  beyond 
aU  doubt  as  primordial  cells;  bodies  destitute  of  a  solid  ceU-membrane, 
having  a  thin  coat  of  protoplasm  which  *  bubbled '  out  in  water,  to  which 
adhered  a  thick  investment,  coloiu-ed  bright  green  by  numerous  imbedded 
chlorophyll-granules,  sm-rounding  a  central  ca^-ity  filled  with  transparent 
fluid.  The  fluid  contained  in  the  spore  in  which  the  two  primordial  cells 
were  immersed,  was  not  colouiless,  but  rendered  tui'bid  by  numerous  im- 
measui-ably  smaU  granules  exhibiting  molecular  motion.  In  August  each  of 
the  ellipsoidal  primordial  cells  had  divided  into  two  globular  cells,  of  similar 
character  to  the  mother-cell.  Towards  the  end  of  September,  some  of  the 
spores  exhibited  another  such  division,  so  that  they  then  contaiaed  eight,  not 
globular,  but  strongly  flattened  primordial  cells.  Most,  however,  passed 
through  the  winter-rest  imchanged,  during  which  the  majority  died.  At 
the  beginning  of  April  of  the  next  year,  the  spinous,  transparent,  outermost 
layer  of  the  coat  was  more  or  less  completely  decayed  on  all  the  spores,  even 
on  those  which  were  still  to  be  recognized  as  living  by  the  vivid  green  colour 
of  the  contents.  AU  the  spores  still  alive  contained  at  least  eight,  many  six- 
teen daughter-cells,  all  very  strongly  flattened,  almost  discoid.  In  several 
spores  the  outline  of  the  daughter-cells  was  no  longer  cu^ular,  but  displayed 
two  shallow  lateral  notches.  The  still -existing,  brownish,  inner  layer  of  the 
spore-coat  was  now  seen  to  be  softened ;  it  no  longer  exhibited  its  former 
brittleness,  and  it  was  difficiilt  to  crack  it  by  pressure.  Daughter-cells  whose 
lateral  constrictions  were  most  strongly  marked,  were  about  half  as  large 
again  as  the  circular,  whose  diameter  about  equalled  that  of  the  isthmus  of 
the  former,  and  they  almost  entirely  filled  up  the  cavity  of  the  spore.  When 
these  were  pressed  out  from  the  crushed  spore,  their  form  and  size  agreed 
almost  exactly  with  that  of  Cosmarium  Meneghinii. 

"  I  saw  similar  phenomena  in  the  spores  of  Cosmarmm  undulatum  (Corda), 
in  which  the  investigation  is  rendered  very  difficult  by  the  minute  size,  and 
which,  cultivated  for  some  months  in  my  room,  entered  abundantly  into  con- 
jugation. In  this,  again,  I  observed  the  contraction  of  the  green  contents  of 
the  cell  into  a  globule  occupjdng  the  central  part ;  the  division  of  this  ball 
into  two,  foiu',  eight,  and  sixteen  spherical  masses ;  finally,  the  transition  of 


OF  THE  DESMIDIE^.  19 

these  daughter-cells  of  the  last  generation  from  the  form  of  cii^cular  lenticular 
bodies  into  two-lobed  ones  like  the  mother-plant.  Here  the  young  Cosmaria, 
whose  diameter  amoimted  to  scarcely  ith  or  ith  of  that  of  the  mother-plant, 
were  set  free  by  the  very  gradual  solution  of  the  membrane  of  the  spore.  A 
similar  process  very  probably  occurred  in  Cosman'um  tetraoplithcdmum,  but 
could  not  be  observed  there,  from  the  circumstance  that  aU  the  materials  had 
been  used  up  in  the  investigation. 

''  These  facts  place  it  beyond  doubt  that  the  contents  of  the  spores  produced 
by  the  conjugation  of  two  individuals  of  Cosmarium,  are  transformed  by 
repeated  binary  division  into  eight  or  sixteen  daughter-ceUs,  which  assume  the 
form  of  the  mother- cell,  and  finally  become  free  by  the  solution  of  the  wall 
of  the  spore.  Such  behaviour  of  the  spores  had  indeed  been  rendered  pro- 
bable before,  by  the  discovery  of  the  vesicular  structure  observed  by  Focke 
and  Ealfs,  which  enclosed  a  nimiber  of  small  Chsteria,  for  the  most  part 
beginning  to  divide.  But  the  certainty  which  can  only  be  given  by  direct 
observation  of  the  development  was  altogether  wanting. 

''  The  development  of  four  daughter-cells  in  the  interior  of  spores  produced 
by  the  conjugation  of  tvv^o  individuals  (with  participation  of  the  whole  of  the 
cell-membrane),  has  been  demonstrated  by  Alex.  iJraun  for  the  Palmellacean 
Pahnoglcea  macrococca,  Kiitz.  (?)." 

Sporangia  are  the  only  portions  of  Desmidieae  of  past  eras  which  have  been 
preserved  to  us  in  a  truly  fossil  condition.  Ehrenberg  discovered  certain 
orbicular  and  spinous  bodies  in  flint,  some  of  which  he  referred  to  the  genus 
Xanihidium  among  the  Desmidiese,  and  others  to  Pyxidicula  among  the  Dia- 
tomese.  However,  as  Mr.  Ealfs  remarks  (p.  13),  this  association  is,  no  doubt, 
erroneous,  since  in  tnie  Xanthidia  the  cell  is  compressed,  bipartite  and  bi- 
valved,  whilst  in  these  fossils  it  is  globose  and  entire,  and  there  can  be  no 
doubt  that  they  are  fossil  sporangia  (XYII.  506  to  515). 

To  quote  ]\Ii\  Ralfs's  account  (p.  13) — "  The  fossil  forms  vary  like  recent 
sporangia,  in  being  smooth,  bristly,  or  furnished  with  spines,  which  in  some 
are  simple,  and  in  others  branched  at  the  extremity.  Sometimes,  too,  a 
membrane  may  be  traced  even  more  distinctly  than  in  recent  specimens,  either 
covering  the  spines  or  entangled  with  them.  Some  writers  describe  the  fossil 
fonns  as  having  been  silicious  in  their  living  state ;  but  Mr.  Williamson  in- 
forms me  that  he  possesses  specimens  which  exhibit  bent  sj^ines  and  torn 
margins,  and  thus  whoUy  contradict  the  idea  that  they  were  silicious  before 
they  were  imbedded  in  the  flint." 

Another  mode  of  propagation  is  presumed  to  take  place  by  means  of  the 
active  molecules  seen  within  the  fronds  of  Desmidieae — in  other  words,  by 
zoospores,  as  happens  in  many  families  of  Algae.  M.  Morren  advanced  this 
notion,  and  imagined  the  minute  particles  which  he  denominated  "  propa- 
gules,"  to  be  at  once  transformed  into  small  fronds.  Mr.  RaKs  countenances 
the  opinion  so  far  as  to  say  that  the  escape  of  the  granular  contents  of  the 
mature  frond  is  probably  one  mode  of  reproduction.  He,  however,  likewise 
regards  (as  Prof.  W.  Smith  observes)  the  swarming  of  the  granules  as 
identical  with  the  movement  of  the  zoospores,  and  confesses  to  his  ignorance 
of  the  history  of  the  motile  granules  after  their  escape.  But  we  perfectly 
coincide  with  Prof.  Smith  that  the  swarming  of  the  granules  within  a  mature 
frond  is  in  most  cases  "  a  disturbance  attendant  upon  the  decay  of  the 
granular  mass,"  and  not  a  phenomenon  connected  with  reproduction.  Still 
our  acquaintance  with  the  swarming  granules,  particularly  after  their  escape 
from  the  frond,  is  so  imperfect  that  it  is  useless  to  speculate  on  their  func- 
tional purpose. 

Ehrenberg,  to  carry  out  his  hypothesis  of  the  animal  nature  of  Desmidieae, 

c2 


20  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

and  to  assimilate  their  organization  -w^ith  that  he  attributed  to  other  Poly- 
gastrica,  represented  the  larger  oil-vesicles  and  starch-grains  to  be  either 
stomach-sacs  or  ova, — at  one  time  the  one,  at  another  the  other,  in  a  purely 
arbitrary  fashion.  Some  again  of  the  more  transparent  or  refracting  vesicles 
were,  with  no  shadow  of  reason,  called  fecundating  or  spermatic  glands.  An 
attempt  to  show  the  error  of  such  an  hypothesis  of  internal  organization 
would  be  futile  and  uncalled  for  at  the  present  day. 

Habitats,  Distribution,  Appearance  in  Masses,  and  Vital  Endoa\tvients 
OF  Desmidie^.  Vegetable  Nature  and  Affinities.  Mode  of  Collection. — 
The  Desmidieae  live  in  fresh  water,  in  ditches  and  ponds,  and  rarely  in 
streams,  except  when  these  are  very  sluggish.  They  will  often  rapidly  aj^pear 
in  a  recent  collection  of  water,  and  are  not  destroyed  when  the  pool  is  dried 
up,  as  their  reappearance  immediately  after  a  shower  proves ;  nevertheless, 
ponds  which  do  not  dry  up  dui^ing  the  summer,  and  pools  in  boggy  ground, 
are  richer  in  these  organisms,  provided  the  water  remains  sweet.  To  quote 
Mr.  E-alfs's  experience — "  The  Desmidieae  prefer  an  open  country.  They 
abound  on  moors  and  in  exposed  places,  but  are  rarely  found  in  shady  woods 
or  in  deep  ditches.  To  search  for  them  in  turbid  water  is  useless ;  such 
situations  are  the  haunts  of  animals,  not  the  habitats  of  the  Desmidieae,  and 
the  waters  in  which  the  latter  are  present  are  always  clear  to  the  very  bottom." 
They  no  doubt  inhabit  the  fresh  waters  in  all  parts  of  the  globe,  for  they 
have  been  found  wherever  sought  in  each  hemisphere.  Still  the  several 
genera  and  species  are  not  universal,  for,  as  in  the  case  of  higher  plants, 
some  species  are  peculiar  to  one  country,  others  to  another ;  and  in  the  same 
country  the  presence  and  prevalence  of  any  one  species  wiU  be  determined 
by  the  physical  features  of  localities,  by  the  nature  of  the  soil,  and  the  like. 
The  distribution,  however,  of  the  Desmidieae  has  not  been  inquired  into  so 
fully  as  to  justify  any  attempt  to  lay  down  special  laws. 

Oftentimes  in  smaU  collections  of  water,  Desmidieae  of  the  same  or  of 
various  species  and  genera  multiply  to  such  an  extent  as  to  colour  the  water, 
and  in  the  case  of  the  filamentous  species,  to  appear  in  filmy  masses  on  the 
surface  or  at  the  bottom  of  the  pool ;  still  this  enormous  multiplication,  and 
the  coloration  of  the  water  thej^  inhabit,  are  far  less  frequent  in  the  case  of 
the  family  in  question  than  with  others — for  instance,  the  Eugleneae,  or  even 
the  Diatomeae. 

Mrs.  Thomas  {op.  cit.  p.  36)  has  described  the  green  masses  formed  by 
Cosmarium,  which  duiing  summer  and  autumn  "  would  float  to  the  surface, 
rapidly  disengaging  oxygen  as  the  sun  shone  on  them,  and  sinking  again  to 
the  bottom  with  the  coolness  of  the  evening.  Later  in  the  year,  masses  would 
adhere  to  the  inner  surface  of  the  bottle  in  the  form  of  a  thin  pellicle,  or 
collect  in  slimy  masses,  which  appeared  to  dissolve  with  the  warmth  of  the 
coming  spring.  The  green  colour  changed  to  that  of  a  reddish  yellow;  and  it 
might  have  been  thought  that  all  was  dead,  did  not  the  microscope  show  the 
same  beautiful  green,  both  in  young  and  fiill-groAvn  plants,  together  with  much 

bright  red  and  brown,  apparently  the  casings  of  the  sporangia Large 

Cosmaria  still  in  active  motion  (the  remains  of  the  mature  growth  of  the  pre- 
ceding summer)  lay  imbedded  in  the  mass,  when  a  small  portion  was  separated 
for  microscopic  observation,  as  well  as  clusters  of  young  ones  (I.  13,  14). 
When  the  bottle  had  remained  more  than  a  year  untouched,  except  for  change 
of  water,  these  masses  increased  in  leathery  hardness ;  green  life  was  not 
extinct,  but  became  feeble  in  colour,  and  too  much  changed  to  warrant  further 
observations,  while  a  small  portion  placed  in  another  bottle,  and  more  freely 
exposed  to  the  light,  multiplied  with  great  rapidity." 
•    Many  of  the  vital  endowments  of  the  Desmidieae  have  already  been  de- 


OF  THE  DESMIDIEiE.  21 

scribed:  we  have  noted  their  process  of  reproduction  and  of  growth,  the 
molecular  and  circulatory  movements  within  them,  their  slight  locomotive 
power ;  but  besides  these,  there  are  others  requii'ing  to  be  mentioned :  for 
instance,  their  powers  of  secretion  are  highly  pronounced ; — the  production 
of  firm  envelopes  to  fronds  and  sporangia  ;  the  formation  of  starch-grains,  of 
colouring  matter,  and  of  oil-globules  within ;  the  exhalation  of  oxygen  from 
the  surface, — a  respii^atory  act ;  and  lastly,  their  ability  to  resist  decomposition. 

The  Desmidieae  serve  as  food  to  many  sorts  of  small  aquatic  animals,  to 
the  Rotifera,  to  various  Annelida  and  small  Ciiistacea,  and  to  the  fi^eshwater 
Mollusca.  They  are  supposed  also  to  preserve  the  freshness  of  the  water, 
and  by  the  oxygen  they  exhale,  to  fiu'nish  the  vital  air  necessary  to  the 
respii'ation  of  the  aquatic  animals  found  Avith  them.  They  are  subject  to 
destraction  not  only  in  the  way  of  supplying  food  to  animals,  but  also  by 
disease.  For  instance,  Cohn  has  shown  (Enhu.  d.  mih\  Alg.)  that  the 
Closteria  are  attacked  by  a  microscopic  unicellular  fimgus,  called  Ohytridiiim, 
the  spores  of  which  affix  themselves  on  the  integument,  and  on  germinating, 
penetrate  the  cavity  of  the  frond  by  their  delicate  fibres,  and  induce  a  pro- 
gressive breaking-up  and  absorption  of  the  contents,  until  nothing  but  the 
empty  hull  of  the  plant  remains. 

Mr.  Ralfs  has  the  following  remarks  (p.  13) : — '^  In  all  the  Desmidieae,  but 
especially  in  Clostenum  and  Micrastenas,  small,  compact,  seed-like  bodies  of 
a  blackish  colour  are  at  times  met  "with.  Their  situation  is  uncertain ;  and 
their  number  varies  from  one  to  four.  In  their  immediate  neighboui^hood  the 
endochrome  is  wanting,  as  if  it  had  been  requii^ed  to  form  them,  but  in  the 
rest  of  the  frond  it  retains  its  usual  character  and  appearance.  I  cannot 
satisfy  myself  respecting  the  nature  of  these  bodies ;  but  I  believe  them  to 
arise  from  an  unhealthy  condition  of  the  plant,  or  else  to  be  parasitic."  With 
respect  to  the  views  expressed  in  this  extract,  we  are  disposed  to  think  Mr. 
Ralfs  right  in  his  conclusion  that  the  black  bodies  he  met  with  were  parasitic ; 
and  on  comparing  his  account  ^yith.  the  figures  and  description  of  the  parasitic 
Chytridium  in  Cohn's  memoii^  (Enhv.),  it  seems  to  us  highly  probable  that  the 
globules  referred  to  were  no  other  than  the  spores  of  that  microscopic  fungus. 

Tor  a  long  time  discussion  was  rife  respecting  the  animal  or  the  vegetable 
nature  of  the  Desmidieae.  That  it  was  the  former  was  the  prevailing 
notion  until  within  the  last  few  years,  when  the  improvements  in  the 
microscope,  and  the  more  extended  and  accurate  knowledge  of  the  features 
of  vegetable  life  in  its  simplest  manifestations,  rendered  this  opinion  no  longer 
tenable,  and  at  the  present  day  it  may  be  considered  exploded.  It  is  un- 
necessary, therefore,  to  go  minutely  into  this  question ;  for  it  will  suffice  to 
indicate  the  most  striking  distinctive  characters,  especially  those  which  rest 
upon  the  affinities  of  the  family  under  consideration.  Those  readers  who 
would  see  the  point  fully  discussed  will  do  well  to  refer  to  Mr.  Ealfs's  admi- 
rable monograph,  to  which  we,  and  others  also,  resort  as  to  a  mine,  for  the 
materials  to  build  up  a  histoiy  of  the  Desmidieae. 

An  old  argument  advanced  by  Ehrenberg  for  the  animality  of  the  Des- 
midieae, was,  that  they  had  a  power  of  voluntary  movement  like  animals. 
Without  staying  to  consider  the  loose  and  unphllosophic  use  of  this  term 
voluntary,  as  applied  to  the  motion,  whether  in  the  Desmidieae  or  in  the 
simplest  animal  existences,  its  occurrence  can  be  no  proof  of  animal  life, 
seeing  that  it  is  exhibited  by  acknowledged  plants,  and  in  a  still  more  marked 
manner  by  their  spores.  Moreover,  such  movements  are  doubtless  effected 
by  cilia,  both  in  the  animal  and  vegetable  world  alike,  and  are  likewise 
determined  by  the  vital  processes  going  on  within  and  also  mthout  these 
simple  organisms,  in  relation  with  external  media  and  ^dth  surroimding 


22  GENEEAL  HISTORY  OF  THE  rNTUSOEIA. 

physical  conditions.  Siebold,  quoting  Nageli's  opinions,  says  (J.  M.  S.  i. 
p.  120) — "  The  slow  turning,  and  at  the  same  time  rare  movements  of  the 
Closteria  (the  genus  in  which  motion  is  more  evident),  present  no  character 
of  spontaneity;  these  motions  are  merely  the  consequence  of  an  active 
endosmosis  and  exosmosis,  by  which  the  water  immediately  surrounding  the 
Closteria,  and  consequently  themselves,  are  put  into  motion."  Again,  as  Mr. 
Ealfs  remarks,  the  motive  power  is  less  in  degree  than  in  the  Diatomece. 

Cell-multiphcation  by  fission  or  transverse  division,  enumerated  by  Ehren- 
berg  as  an  animal  peculiarity,  is  now  so  completely  established  as  a  vegetable 
phenomenon,  that  it  can  claim  no  consideration  when  the  question  of  the 
actual  affinities  of  a  disputed  organism  is  to  be  solved.  And  equally  unde- 
serving of  critical  examination  at  the  present  day  is  the  complex  animal 
organization  attributed  by  the  Berlin  microscopist  to  the  fronds  of  Desmidieae. 
Concerning  the  apparent  sac  containing  the  moving  particles  in  the  Closteria 
and  in  other  genera,  regarded  by  Mr.  Dahymple  as  a  vegetable  peculiarity, 
Mr.  Ralfs  observes,  "  I  confess  I  am  unable  to  refer  to  any  example  in  other 
Algae  of  terminal  globules  like  those  present  in  the  Closteria,  but  neither  can 
one  be  found  amongst  animals ;  and  if  in  some  respects  they  have  an  analogy 
with  organs  belonging  to  the  latter,  in  others  they  agree  better  mth  vegetable 
life."  On  another  argument  raised,  the  same  author  remarks,  "  The  eon- 
traction  of  the  internal  membrane  of  the  Closteria,  or  the  expulsion  of  their 
contents  on  the  application  of  iodine  or  other  reagents,  cannot  be  rehed  upon 
as  a  satisfactory  test  for  determining  their  nature ;  for  the  blandest  fluids  will 
in  some  cases  (both  among  recognized  Algee  and  the  Closteria  themselves) 
occasion  \iolent  action."  On  the  other  side  of  the  question,  the  act  of  swarm- 
ing, the  emission  of  actively  motile  germs  (presumed  in  this  family),  the 
presence  of  starch  and  of  chlorophyll,  the  chemical  relations  between  these 
substances,  and  also  \\'ith  the  oily  matters  formed  in  the  fronds,  the  exhala- 
tion of  oxygen  in  sunhght,  and  the  absence  of  azotized  material  in  their 
chemical  constitution  furnish  reasons  for  arranging  the  Desmidieae  with 
plants.  Besides  these  reasons,  others  are  found  in  the  general  form  and  in 
the  modes  of  propagation  being  precisely  analogous  with  those  in  admitted 
unicellular  Algae.  Theu-  intimate  affinities  with  Alga3  are  shown  by  the  fact 
that  Meneghini  and  Kiitzing  placed  Metnsmopcedia  among  the  Desmidieae, 
and  that  Braun  refers  the  two  genera  Scenedesmiis  and  Pediastrum,  included 
by  Ehrenberg  himself  in  the  family  in  question,  to  the  Palmellaceae.  The 
process  of  conjugation,  which  has  been  often  appealed  to  as  a  characteristic 
of  plant-life,  would  appear,  however,  to  be,  in  exceptional  cases  and  under 
peculiar  modifications,  also  an  animal  phenomenon,  and  therefore  inapplicable 
as  a  test. 

Meneghini,  who  contends  for  the  animality  of  the  Diatomeae,  has  pro- 
nounced {B.  S,  p.  497,  1853)  the  opinion  that — "  The  Closteria  and  Des- 
midieae in  general  are  plants,  and  not  animals.  In  the  actual  state  of  science 
we  are  compelled  to  admit  this  proposition.  The  organic  structui'e,  the  phy- 
siological phenomena,  the  history  of  their  development,  the  chemical  materials 
they  contain,  manifest  in  these  beings  a  perfect  correspondence  with  others, 
which  in  every  point  of  view  correspond  with  the  abstract  idea  of  a  plant. 
But  what  they  present  in  common  with  other  beings  evidently  animal,  is 
merely  an  appearance,  or  at  the  most,  a  resemblance  in  external  form. 
Ehrenberg  was  misled  by  this  appearance,  and,  guided  by  this  fallacious 
similitude,  thought  that  he  discovered  in  the  Desmidieae  the  same  organic 
pecuHarities  which  proved  the  animahty  of  other  beings." 

Kespecting  the  affinities  of  the  Desmidieae,  Mr.  Ralfs  states  that,  "  on  one 
side,  they  are  allied  to  the  Conjugatae  (Zygnemeae)  by  similarity  of  reproduc- 


OF  THE  DESillDIE^.  23 

tion,  and  on  the  other  to  the  Palmelleae,  by  the  usually  complete  transverse 
division,  and  by  the  presence  of  a  gelatinous  investment.  Indeed  the  relation 
to  the  latter  is  so  intimate,  that  it  is  difficult  to  say  to  which  family  some 
genera  belong.  .  .  .  Some  species  of  Scenedesmus  may  be  allowed  to  have  an 
almost  eqnal  claim  to  rank  with  either."  Again,  they  are  related  to  the 
Diatomese  by  similarity  in  the  reproductive  process. 

In  Ehrenberg's  system  of  Polygastria,  the  Closteria  were  placed  together 
as  a  distinct  family,  imder  the  name  of  Closterina,  whilst  aU  the  other  genera 
of  Desmidieae  were  ranged  as  a  section  of  the  Bacillaria.  This  separation, 
based  as  it  was  upon  presumed  sti-uctural  peculiarities,  is  no  longer  accepted 
by  microscopists,  who  cojoin  Closterium  with  the  several  genera  included  in 
Ehrenberg's  section  Desmidiaeea  in  one  group — the  Desmidieae. 

The  division  of  this  family  proposed  by  Mr.  Ralfs  is  made  according  as — 
1.  The  plant  forms  an  elongated  jointed  filament  (by  incomplete  division  of 
its  cells) ;  or — 2.  The  frond  is  simjile,  from  complete  transverse  division,  and 
distinctly  constricted  at  the  junction  of  the  segments,  which  are  seldom  longer 
than  broad ;  sporangia  spinous  or  tuberculated — rarely,  if  ever,  smooth  ;  or — 
3.  The  fi^ond  is  simple,  as  above,  generally  much  elongated,  never  spinous, 
frequently  not  constricted  at  the  centre;  sporangia  smooth;  or — 4.  Cells 
elongated,  entire,  fasciculated ;  or — 5.  The  fi'ond  composed  of  few  cells,  de- 
finite in  number,  and  not  forming  a  filament. 

This  last  section  is  so  exceptional  in  general  characters,  and  especially  in 
the  mode  of  reproduction,  that  Braun  detaches  it  from  the  Desmidieae  and 
associates  it  with  the  Palmelleae.  In  this  plan  we  coincide,  and  have  there- 
fore treated  separately  this  last  section  of  Mr.  Kalfe,  comprehending  Pedias- 
trmn  and  Scenedesmus. 

Kiitzing  {Species  Algarum)  includes  the  Desmidieae  in  his  subclass  Mala- 
coPHYCE^,  suborder  Chamaephyceae. 

Mr.  Ealfs  enumerated  20  genera ;  viz. — In  Sect.  1,  Hyalotheca,  Didymo- 
jirium,  Desmidium,  Aptogonium,  Splicerozosma.  Sect.  2,  Micrasterias,  Eiuxs- 
trum,  CosmaHum,  Xanthidium,  Arthrodesmus,  Stcmrastrum,  Didymocladon. 
Sect.  3,  Tetmemorus,  Penium,  Docidium,  Clostermm,  Spirotcenia.  Sect.  4, 
Aiikistrodesmus  {Kliaphidiimi).     Sect.  5,  Pediastrum,  Scenedesmus. 

When  compiling  his  systematic  work,  Kiitzing  appears  not  to  have  seen 
Mr.  Ralfs's  monograph,  but  only  his  detached  papers  in  the  Magazines,  and 
consequently  was  imable  to  compare  the  genera  established  by  the  English 
author  ^ith  those  described  by  himself.  The  consequence  is  that  Kiitzing 
describes  several  genera  not  admitted  by  Mr.  Ealfs,  who  has  otherwise  dis- 
posed their  representative  species,  disallowing  the  supposed  distinctive  generic 
character.  Nevertheless  it  seems  desirable  to  enumerate  the  additional 
genera  of  Kiitzing,  since  several  are  new  (unnoticed  by  our  English  authority), 
and  derived  from  the  papers  of  Ehrenberg  or  of  other  obsen^ers,  or  from  his 
own  researches.  Those  instituted  by  Ehrenberg  were  introduced  in  our  last 
edition. 

The  additional  genera  are: — Trochiscia  (K.),  Tetraedron  (K.),  Pifhiscus 
(K.),  Stauroceros  (K.),  Polysolenia  (E.),  Microtheca  (E.),  Polyedrum  (jS'ageh), 
Zygoxantliium  (E.),  Phycastrum  (K.),  Asteroxanthium  (K.),  StepTianoxcni- 
thium  (K.),  Grammatonema  (Agardh),  Bamhushm  (K.),  Isthmosira  (K.), 
Spondyhsum  (Brebisson),  Eucampia  (E.),  Geminella  (Turpin),  Mo-nactinus 
(Corda),  Staurogonia  (K.),  Sphoirastrum  (Meyen),  Sorastrum  (K.),  Coelas- 
trmn  (Nageli),  Bliaplddium  (K.),  Oocardium  (NiigeH). 

The  value  of  the  several  genera  instituted  and  their  characteristics  form 
the  subject  of  the  systematic  historj^  of  the  Desmidieae  by  Mr.  Ralfs  in  the 
subsequent  portion  of  this  treatise. 


24  GENERAL  HISTORY  OF  THE  INFUSORIA. 

SUBFAMILY  PEDIASTEE^. 

(Plate  I.  37  to  69.     Plate  II.  19,  36,  37.) 

This  includes  the  genera  MicrasteHas  and  Arthrodesmus  of  Ehrenberg,  the 
Pediastrum  and  Scenedesmus  of  Ealfs,  Kiitzing,  and  others ;  and,  in  addition 
to  these  two,  to  foUow  NageU's  classification,  Soi^astrum,  Coelastrmn,  and 
probably  also  Splicerodesmus. 

At  the  time  Mr.  Ealfs  wrote,  much  nncertainty  prevailed  respecting  what 
shonld  be  considered  characteristics  of  species,  and  what  were  the  modes  of 
propagation  ;  and  it  is  much  to  be  regretted  that,  although  some  of  the  diffi- 
culties and  doubts  are  removed,  oiu-  knowledge  of  these  microscopic  Algae  is 
far  from  complete. 

Ehrenberg,  in  harmony  mth  the  general  views  of  organization  he  had 
adopted,  placed  Mm^asterias  and  Arthrodesmus  among  the  Desmidieae,  in  the 
class  of  Polygastric  Infusoria,  and  described  the  existence  in  them  of  ova, 
stomach-vesicles,  and  seminal  glands.  Yet  he  was  unable  to  point  out  one 
single  feature  reaUy  indicative  of  their  animal  natm-e,  even  locomotion  being 
unrecognized.  Indeed,  among  those  who  might  be  inclined  to  foUow  the 
distinguished  Berlin  naturalist  in  attributing  an  animal  nature  to  most  of  his 
Polygastria,  the  generality  would  hesitate,  in  face  of  the  many  intimate  ho- 
mologies, structui-al  and  physiological,  between  the  Pediastreae  and  admitted 
AlgaB,  to  predicate  it  of  that  group  of  organisms. 

EiGTJRE,  Composition,  and  Contents  of  Cells. — The  individual  cells  among 
the  Pediastreae  do  not  exist  isolated  and  independent,  but  are  united  together 
in  a  frond,  in  determinate  number  and  in  a  definite  arrangement  for  each 
genus.  In  all  the  species  they  agree  in  having  a  membranous  wall  like  the 
Desmidieae  and  PalmeUeae.  We  confine  ourselves,  it  should  be  imderstood, 
in  noting  the  figure  of  the  cells,  to  the  mature  phase  or  stage,  which,  although 
but  one  of  several  known  phases,  is  that  most  marked,  best  understood,  and 
most  perfect. 

The  cells  of  Scenedesmus  {Arthrodesmus,  Ehr.)  (I.  37  to  43)  are  entire,  oval, 
oblong,  or  fusiform,  with  their  ends  either  rounded  or  pointed.  Theii'  length 
is  from  two  to  four  times  theii'  width  or  thickness,  and  they  are  spherical  on 
a  transverse  section.  They  exliibit  no  constriction  or  sutui^e  at  the  middle, 
neither  in  their  waU  nor  in  theii'  endochrome,  and  in  these  particulars  con- 
sequently differ  fr'om  the  cells  of  true  Desmidieae.  The  membrane  is  fr^e- 
quently  drawn  out  in  the  form  of  straight  or  ciu'ved  spines ;  this  happens 
usually  only  with  the  ceU  at  each  end  of  the  chain  (I.  40,  41) ;  but  in  a  few 
cases,  other  cells  nearest  to  the  outer  ones  become  also  armed  with  spines 
(I.  42).  When  this  extension  to  the  other  cells  occui^s,  Nageli  remarks  that 
the  spines  do  not  appear  on  both  the  superior  and  inferior  extremities  of  each 
cell,  but  only  on  the  upper  of  the  one,  two,  or  three  next  within  the  one 
terminal  cell,  and  on  the  lower  extremity  of  the  same  number  within  the 
other  terminal  cell  (I.  42).  It  is  rare  that  the  central  cells  of  the  chain  are 
armed,  and  even  when  this  occurs  it  is  only  with  short  spines.  In  addition 
to  a  spine,  or,  as  may  happen,  a  pair  of  spines  from  the  upper  and  lower  ex- 
tremity, the  end  cells  at  times  have  a  third  spine  standing  at  right  angles 
from  their  sides  (I.  41). 

The  cells  of  Pediastrum  are  considerably  compressed,  so  that  when  aggre- 
gated they  form  a  flattened  tabular  stmctui-e  (I.  44  to  48,  59  to  69).  In 
figui^e,  as  seen  fr'om  above,  they  vary  according  as  they  occupy  the  margin  of 
the  collection,  i.  e.  are  peripheral,  or  are  central.  The  latter  are  polygonal, 
frequently  hexagonal,  and  no  doubt  owe  this  shape  to  mutual  lateral  pressure 
during  growth  :  the  marginal  cells  have  fewer  sides,  and  are  frequently  irre- 


OF  THE  PEDIASTEE^.  25 

gulaiiy  quadiilateral,  but  their  free  margin  is  more  or  less  deeply  notched, 
and  therefore  bilobed  (I.  44,  45,  53,  62).  The  lobes  are  usually  tapering, 
and  form  a  tubular  process  either  truncate  or  acute  at  the  extremity  (I.  62). 
In  a  few  cases  the  notch  is  not  angular,  but  cui-ved  and  crescentic  (I.  62)  ; 
in  others  again  it  is  deep,  angular,  and  gaping  (I.  52,  II.  27),  and  gives  the 
cell  an  irregular  figure  ;  this  latter  condition  is  more  seen  where  only  a  few 
cells  are  united  together,  and  where  the  lobes  are  not  prolonged  as  pro- 
cesses. In  some  species,  moreover,  the  lobes  are  terminated  by  short  hair- 
like spines. 

The  notch  on  one  side  is  not  confined  to  the  peripheral  ceUs,  but  extends, 
in  several  species,  also  to  the  contained  cells  of  the  frond  (I.  52,  66) ;  their 
lobes,  however,  are  not  tapering,  but  sharply  truncate.  Nageli  instituted  a 
subgenus  of  Pediastrmn  under  the  name  of  Anomopedium,  the  chief  charac- 
teristic of  which  is  the  absence  of  bilobed  peripheral  ceUs  (I.  46,  47,  48). 

The  ceUs  of  Ccelastmm  are  hexangular  (I.  49,  50,  51),  the  central  ones 
very  regularly  so,  whilst  the  peripheral  are  rounded  oif  on  their  free  aspect 
in  one  species,  and  in  another  notched  and  bilobed  (I.  54,  55).  Those,  lastly, 
of  Sorastrum  (I.  56,  57)  are  wedge-shaped  or  triangular,  with  rounded 
angles ;  they  cohere  by  their  apices,  whilst  the  base  is  perij^heral,  often 
rather  concave  or  emarginate,  and,  as  a  rule,  armed  at  each  angle  by  a  pair  of 
short  spines.     On  a  lateral  view  the  cells  are  oblong  (I.  58). 

There  is  a  pervading  uniformity  in  the  contents  of  the  cells  of  the  different 
genera  of  Pediastreae,  which  consist  of  the  usual  vegetable  protoplasm,  and 
are  spoken  of  collectively  as  the  endochrome.  At  first  the  colour  is  very  pale 
green,  but  it  becomes  deeper  with  advancing  age,  and  in  fully  matiu'e  or 
decaying  cells  is  seen  to  change  to  red  or  brownish  red,  just  as  the  leaves  of 
trees  change  colour  on  the  approach  of  autumn.  At  first,  the  protoplasm  is 
clear  and  homogeneous,  but  in  course  of  time  granules  appear,  enlarge  in 
bulk,  and  multiply  in  number.  Moreover,  each  cell  presents  a  single  ehlo- 
rophyU-vesicle,  which  is  least  discernible  in  very  yoimg  and  in  very  old  cells 
(I.  53  to  58).  It  is  ordinarily  seen  in  or  about  the  centre  of  the  cell,  but 
may  occur  on  one  side,  as  in  Pediastrum  Rotula.  Around  this  vesicle  are 
seen  in  several  species  clear  cii^cular  spaces  or  globules,  recalling  those  of 
Closterium,  varying  in  number  in  difierent  cases  from  two  to  six  (I.  44,  45, 
53).  In  Pediastmm  Rotula,  Nageli  observed  two  such ;  in  P.  Boryanum  and 
P.  Selencea  (I.  44,  45),  from  two  to  six ;  in  the  species  of  Scenedesmus  and 
of  So7%istrum  (I.  57),  one  hyaline  space.  This  author  likewise  represents  the 
relative  position  of  the  chlorophyU-vesicle  and  of  the  translucent  space  to  be 
constant  in  similar  fronds.  In  those  made  up  of  two  cells  only,  the  chloro- 
phyU-vesicle  is  placed  outside,  whilst  the  clear  cavity  lies  against  the  parti- 
tion-wall. In  chains  of  four  to  eight  cells  the  chlorophyll- vesicle  is  external 
relatively  to  the  central  cell,  and  the  clear  space  internal  (I.  40,  41), — the 
position  being  regulated,  not  by  the  partition -wall,  as  in  the  Palmelleae  in 
general,  but  by  the  centre  of  the  entire  frond.  Oil-globules  are  also  con- 
tained in  the  cells ;  their  presence  is  readily  demonstrated  by  the  addition  of 
tincture  of  iodine,  for  they  continue  colouiiess  when  the  surrounding  mass  is 
coloured  brown  ;  their  position  often  exhibits  much  regularity.  Unless  the 
chlorophyll- vesicle  be  esteemed  nuclear,  no  nucleus  has  been  cUscemed  in  the 
cells  of  Pediastreae.  On  one  occasion  Nageli  saw,  in  Pediastrum  Boryanum,  the 
endochr^ome  disposed  in  a  radiating  manner  around  the  chlorophyll-vesicle, 
an  arrangement  which  often  obtains  in  Algse,  and  in  many  vegetable  ceUs 
where  there  is  a  central  nucleus. 

T^UMBER    AND    DISPOSITION    OF  THE  CeLLS  IN  THE    FllONDS. The  CcUs  of  Pc- 

diastrese  are  always  united  together  in  compound  fronds.     The  number  so 


26  GENERAL  HISTORY  OF  THE  rNFUSOEIA. 

united,  and  their  mode  of  combination,  differ  in^  the  different  genera  and 
species. 

In  Scenedesmus  the  cells  are  arranged  (I.  37  to  43)  in  single  linear  series, 
side  by  side,  united  by  a  mucous  hj^aline  matrix,  which  is  less  abundant 
than  in  Pediastrum.  Two,  mostly  four,  and  less  frequently  eight  cells  are 
concatenated ;  and,  as  a  rule,  the  line  of  union  extends  the  entire  length.  Ex- 
ceptions occur,  owing  to  the  junction-surfaces  being  less  extensive,  in  the  form 
of  chains  of  cells  having  a  zigzag  border,  every  alternate  cell  being  depressed 
below  the  normal  plane,  or  in  that  of  an  obhque  chain,  having  each  member 
in  succession  depressed  beneath  the  preceding.  Sometimes  two  rows  of  eight 
cells  each  lie  side  by  side  (I.  38),  so  that  the  one  dovetails  into  the  other  by 
the  alternate  elevation  and  depression  of  their  component  cells  :  this  may 
happen  in  the  whole  extent  of  the  two  coherent  chains,  or  in  a  portion 
only  of  their  length  at  one  or  other  extremity ;  or  one  chain  may  be  broken 
into  two  segments,  each  dovetailed  to  the  other  chain  at  opposite  ends  so  as 
to  leave  an  unoccupied  central  space.  The  alternation  of  the  cells  in  fronds 
composed  of  two  rows,  is  the  result,  according  to  Mr.  Ealfs,  of  the  obhque 
manner  of  division.  In  the  genus  Pediastrum  the  fronds  are  generally  com- 
posed of  a  larger  number  of  cells  than  in  Scenedesmus,  disposed  in  the  same 
plane  according  to  a  definite  and  usually  concentric  arrangement,  and  foiming 
compound  steUate  fronds  (I.  52,  53,  62,  66,  67),  whence  the  term  Micras- 
terias  (httle  star-like  beings)  invented  by  Ehrenberg,  and  also  the  second  half 
of  the  generally  adopted  term  {Pedi)-astrum. 

To  distinguish  species,  Ehrenberg  chiefly  employed  the  number  of  the 
cells  in  a  frond — both  the  entire  number  and  that  of  each  concentric  circle, 
together  with  the  number  of  circles.  Succeeding  naturahsts,  however,  have 
pointed  out  that  the  number  of  cells  in  the  same  species  is  subject  to  con- 
siderable variation.  TmT^)in  detected  the  true  law  determining  their  number, 
and  Nageh  fui^ther  illustrated  and  enforced  it.  The  latter  wiites  that 
{Einzell  Alg.  p.  92)  ''  the  cells  are  united  2,  4,  8,  16,  32,  or  64  together 
in  a  frond.  These  numbers  are  always  constant  in  young  fronds  without 
exception.  In  older  specimens  one  or  more  cells  may  be  lost,  and  the  frond 
become  therefore  apparently  irregular.  These  cells  do  not  spontaneously 
detach  themselves  from  the  rest,  but  die,  and  are  partially  or  entirely 
dissipated,  as  a  consequence  of  injury  from  some  external  cause,  probably  in 
most  cases  by  small  aquatic  animals.  They  occur  in  all  stages  of  destruc- 
tion, and  when  entirely  vanished,  the  vacant  space  indicates  their  fonner 
position.  The  cells  are  aggregated  together  in  a  single  plane,  which  possesses 
mostly  a  circular  or  somewhat  rounded  outline ;  but  in  the  disposition  of  the 
cells  there  is  considerable  variety.  In  the  case  of  4  cells  they  are  either  all 
in  opposition  (II.  27),  or  only  2  in  the  centre ;  with  8  cells,  one  usually 
lies  in  the  middle,  and  the  other  7  surround  it  in  a  circular  manner 
(I.  52);  less  commonly,  2  are  central  and  6  peripheral  (I.  62);  rarely, 
one  occupies  the  centre  with  6  around  it  in  a  circle,  whilst  the  remaining 
or  eighth  cell  is  placed  on  the  perii^heiy ;  and  stiU  rarer,  the  disposition  is 
quite  irregular.  Where  16  cells  are  combined,  the  rule  is  that  there  is  one 
in  the  centre  surrounded  by  an  inner  circle  of  5  and  an  outer  circle  of  10. 
At  times,  4,  5,  or  6  internal  cells  are  encii^cled  by  12,  11,  or  10  outer 
ones  (I.  53,  66,  67),  whereby  a  double  ring  is  produced:  more  rarely 
the  arrangement  is  completely  irregular.  Again,  32  cells  are  mostly 
so  placed  that  one  central  cell  has  around  it  3  circles,  the  innermost  of 
5,  the  middle  of  10,  and  the  outer  of  16  cells ;  less  frequently,  the  3 
circles  are  respectively  composed  of  5,  11,  and  15,  or  of  6,  10,  and  16; 
occasionally  5  internal  cells  have  2  outer  scries,  one  of  11,  the  other  of  16 


OF  TUE  PEDIASTKE^.  27 

cells;  or  6  cells  are  enclosed  by  11  and  15,  or  by  10  and  16  ;  or,  lastly,  the 
distribution  is  partly  or  completely  iiTegular.  In  the  case  of  64  cells,  no 
regular  aggregation  frequently  is  observable :  sometimes  2  or  3  external  con- 
centric series  are  perceptible,  where  the  position  of  the  inner  cells  follows 
no  rule ;  less  fi^equently,  the  concentric  arrangement  can  be  followed  to  the 
centre ;  when  this  is  the  case,  one  central  cell  may  be  enclosed  by  four 
series  respectively  of  6,  13,  19,  25,  or  of  7,  13,  19,  24  cells;  or  again,  2 
middle  cells  have  around  them  8,  13,  18,  23,  or  7,  12,  19,  24,  or  7,  13,  19, 
23  ceUs  in  four  rows ;  or  fui'ther,  3  central  ceUs  have  8,  13,  18,  22  ceUs 
around,  and  so  forth. 

"  The  form  of  the  genus  PecUastrum  has  in  general  a  decided  tendency  to 
a  concentiic  disposition  of  the  ceUs.  Thus  4  cells  combine  in  1,  8  in  2, 
16  in  3,  32  in  4,  and  64  in  5  circles.  A\Tien  this  concentric  arrangement  is 
distui^bed,  it  occui's  more  frequently  in  larger  than  in  small  fi'onds,  and  more 
frequently  among  the  central  than  the  peripheral  ceUs." 

Braun  {Gen.  Nov.  p.  71)  has  entered  much  in  detail  respecting  the  number 
ajjd  disposition  of  the  cells,  and  arrived  at  the  same  general  results  as  Nageli. 
He  observes  that  "  the  same  numerical  law  is  common  to  all  the  species  [of 
PecUastrum'],  but  the  number  may  vary  more  or  less  within  the  legitimate 
series,  even  indeed  in  one  and  the  same  species :  the  disposition  also  is  liable 
to  variation  where  there  is  the  like  number  of  cells  in  the  same  multifarious 
species  ;  and  this  so  much  the  more  the  greater  the  number  of  cells. . ,  .The 
legitimate  (normal)  series,  viz.  1,  2, 4,  8, 16,  32,  64, 128,  is  explained  by  the 
binary  division  which  takes  place  in  the  formation  of  gonidia,  and  which  is 
quicldy  arrested  or  continued  for  a  longer  period. 

"  I  have  no  dii-ect  observations  to  show  whether  specimens  consisting  of  a 
single  cell  are  generated  singly  from  the  parent  cell,  or,  after  being  developed 
in  company  with  others,  they  have  become  dispersed  by  some  accident,  which 
is  very  probable.  Such  specimens,  belonging  pretty  clearly  to  PecUastrum 
Ehrenbergii,  occur  eveiyw'here  in  company  with  the  multicellular  fi'onds  of 
this  species.  Unicellular  examples  of  other  species  are,  it  would  seem,  very 
rare.  I  have  seen  one  such  of  P.  Motida  ;  of  some  which  I  think  should  be 
assigned  to  P.  Boryanum.  Bi-cellular  specimens  I  have  only  observed  in  the 
case  of  P.  Ehrenbergii  :  instances  of  128  cells  have  frequently  occurred  to  me 
with  P.  valgum,  and  twice  with  P.  Boryanum.  The  other  numbers  are  common, 
and  occur  in  very  many  or  in  all  species,  or  in  the  majority ;  certain  of  them 
indeed  much  more  frequently  than  others. 

"  Numbers  divergent  fi^om  the  normal  series,  whether  incomplete  or  more 
than  complete  (supra- complete),  are  rare,  whilst  veiy  divergent  ones  are 
very  rare.  The  former  have  their  origin  in  the  process  of  fission  and  the 
formation  of  gonidia,  when  one  or  other  segment  in  the  penultimate  division 
remains  undivided,  or  divides  once  too  often.  Thus  in  P.  Boryanum,  specimens 
are  occasionally  found  ha\dng  15  instead  of  16,  31  for  32,  63  for  64  cells,  or 
on  the  contrary,  17  for  16.  Examples  of  65  in  lieu  of  64  cells  have  occuiTed 
to  me  in  P.  asperum.  The  latter,  i.  e.  those  numbers  widely  divergent,  may 
originate,  if  in  the  earlier  division  of  the  cytioplasm  [protoplasm]  some  seg- 
ment is,  as  it  were,  passed  by,  and  subsequently  enters  again  in  the  series  of 
segmentation.  In  this  way  the  numbers  entering  into  the  series  3,  6,  12, 
24,  48,  examples  of  which  are  at  hand,  may  be  explained.  Three  cells  have 
been  met  mth  by  me  in  P.  Ehrenbergii,  and  more  frequently  6,  both  in  this 
species  and  in  P.  Rotula ; .  . .  .24  cells,  once,  in  P.  asperum.^' 

Braun  adds  that,  if  any  person  should  doubt  that  the  number  of  cells  differs 
in  the  same  species,  he  has  only  to  inspect  collections  made  in  the  same  place 
and  li\ing  imder  like  conditions,  and  to  note  the  unequal  fonns  produced 


28  GENERAL  HISTOEY  OF  THE  INFUSOEIA. 

from  the  same  parent  individual,  and  lastly,  to  remark  the  analogy  presented 
in  other  allied  genera,  e.  g.  Scenedesmus,  Sorastrum,  and  Coelastrum,  to  con- 
vince himself  of  the  fact. 

Moreover,  as  shown  by  Nageli,  when  the  number  of  cells  is  the  same  in  a 
frond  (coenohium,  Braun),  their  arrangement  varies  considerably,  tending 
more  and  more  to  irregularity  as  the  ceUs  are  more  multiplied.  "  The  normal 
and  most  frequent  disposition  is  orbicular,  the  cells  being  arranged,  according 
to  their  number,  in  one  or  several  concentric  circles,  around  either  a  single 
central  cell  or  none  at  all.  Where  two  cells  are  placed  in  the  centre,  the 
circles  around  incline  to  an  elliptic  figure;  fi^om  this  a  transition  to  an 
elongated  form  still  more  aberrant  from  the  orbicular  type  is  indicated,  in 
which  the  elongate -elliptic  circles  surround  several  intermediate  cells  placed 
in  single  or  double  longitudinal  series.  By  the  less  regular  concentric  or  the 
entirely  confused  disposition  of  the  cells,  the  elliptic  form  passes  at  length 
into  others  still  more  abnormal,  such  as  reniform,  panduriform,  cuneiform, 
&c.,  all  which  agree  in  ha\ing  64  or  128  ceUs.  The  regular  concentric 
arrangement  is  moreover  deranged  by  the  occasional  intercalation  of  ceils 
referable  to  no  one  of  the  circles ;  and  lastly,  owing  to  an  incompleteness 
of  the  circles  of  cells,  they  become  so  connected  one  with  another,  that  a 
spiral  disposition  is  the  result,  which,  although  abnormal  in  every  species,  is 
in  some  specimens  constructed  with  wonderftd  regularity.  All  these  various 
arrangements  arise  from  the  manner  in  which  the  motile  gonidia  are  disposed 
and  marshalled  in  their  first  stage ;  for  these  are  distributed  within  the 
parent  depressed  orbicular  cell,  according  to  the  laws  of  juxtaposition,  in  a 
plane." 

Another  peculiarity  in  the  disposition  of  the  ceUs  in  the  fronds  of  Pedias- 
trwn  is,  that  sometimes,  instead  of  being  all  in  juxtaposition,  so  as  to  form 
an  unbroken  congeries  of  cells,  or,  in  the  language  of  Nageli  (op.  cit.  p.  94), 
instead  of  being  parenchymatic,  apertures  or  interspaces  are  left  between 
them  (I.  53).  This  is  most  seen  where  the  inner  cells  are  more  or  less  bi- 
lobed,  so  that  an  opening  subsists  between  the  lobes  of  each  ceU ;  but  similar 
apertures  may  likewise  occur  at  the  angles  where  the  cells  come  into  contact. 
"When  the  position  of  the  cells  in  the  table  is  regular,  that  of  the  foramina  is 
so  also.  Pediastrwn  Selencea  with  16  cells  has,  as  a  rule,  6  large  and  8  small 
openings ;  the  large  are  bounded  by  3  cells,  the  small  by  2 ;  the  small  spaces 
are  sometimes  absent,  when  the  large  become  very  evident.  Pronds  of  the 
same  species,  having  32  cells,  display  usually  11  larger  interspaces  lying 
betwixt  3  cells,  and  18  smaller  enclosed  between  2  cells. 

Anomopedium,  a  subgenus  of  Pediastrum,  differs  not  only  in  its  peripheral 
cells  not  being  bilobed,  but  also  in  having  its  cells  partially  disposed  in  a  double 
plane  (I.  46,  47,  48).  The  ceUs  which  are  in  the  numerical  series  of  4,  8, 
16,  32,  and  64,  are  subject  to  manifold  arrangements,  and  frequently  aggre- 
gated quite  irregularly.  They  are  mostly  so  placed,  that  in  one,  two,  or  even 
three  directions,  they  can  be  clearly  discerned  to  be  in  parallel  straight  rows. 
A  concentric  disposition  is  quite  exceptional ;  not  unfi-equently,  instead  of  aU 
the  cells  occupying  the  same  plane,  some  form  a  partial  second  layer  upon 
the  other  about  the  middle. 

In  Ccelastrum  (I.  50,  51,  52)  the  hexangular  cells  are  so  arranged  that 
they  form  a  hollow,  globular,  areolar  frond.  Coel.  sphcericum  consists  of  25 
to  40  cells,  which  compose  a  lamina  perforated  by  3,  4,  5,  6,  8  angular  meshes 
(areolae)  somewhat  larger  than  the  cells  themselves,  and  from  13  to  22  in 
number.  Coel.  cuhicmn  consists  of  8  cells  united  in  a  cubical  form,  hollow 
inside  :  on  each  side  are  4  cells  enclosing  a  quadrangular  aperture. 

Lastly,  in  Sorastrum  the  wedge-shaped  or  cordate  cells  (I.  56,  57)  are  all 


OF  THE  PEDIASTEE^.  ^9 

in  close  apposition  and  form  a  globular  frond.  The  cells  in  the  typical  species, 
S.  echinatiun,  are  8  or  16  in  number,  and  so  arranged  that  all  their  apices 
converge  towards  and  meet  in  the  centre  of  the  frond. 

SjyJicerodesmus,  which  probably  is  rightly  accounted  one  of  the  Pediastreae, 
is  named,  but  not  described,  by  Niigeli  ;  we  are,  however,  informed  by  Braun 
(Gen.  Nova,  p.  70,  in  foot-note)  that  its  fronds  are  composed  of  4  spherical 
cells  closely  aggregated  in  a  rhomboidal  form. 

Development  and  Growth. — Seenedesmus  multiplies  by  fission,  as  Ealfs 
believed,  in  an  obhque  direction,  but  according  to  Nageli,  parallel  to  the  long 
diameter  of  the  cells.  The  former  adopted  his  opinion  from  the  features  of 
biserial  chains ;  but  the  latter  interprets  those  appearances  by  the  simulta- 
neous occurrence  of  longitudinal  and  of  transverse  fission  (I.  37,  39). 

The  process  of  self- division  commences  generally  at  the  same  period  in 
each  cell  of  the  frond  (family,  Niigeh),  and  proceeds  with  so  great  rapidity 
that  its  intermediate  stages  are  unobserved.  One  of  the  two  terminal  cells 
(I.  39),  or,  in  an  eight-celled,  probably  the  two,  sometimes  remain  for  awhile 
undivided.  The  cell  separates  into  two,  then  each  of  these  again  into  two 
others,  and  at  times  this  act  of  subdivision  is  repeated  a  third  time.  By  a 
more  prolonged  act  of  segmentation  of  the  cell-contents,  the  result  is  a  number 
of  minute  cells  which  arrange  themselves  in  rows  of  two,  four,  or  eight,  and 
thus  form  miniature  fronds  which  ultimately  escape  the  parent-cell  by  rup- 
tui'e.  Occasionally,  adds  Niigeli,  the  young  fi'onds  are  connected  together 
by  mucus,  formed  by  dissolution  of  the  parent  cell-wall.  Development  takes 
place  in  parallel  planes,  although  by  their  increase  they  become  mutually 
compressed  and  in-egular,  and  the  chains  curved  j)rior  to  their  discharge. 

This  production  of  macrogonidia  and  their  cohesion  into  fronds  has  not 
been  seen  by  Braun,  and  is^  in  his  experience,  an  exceptional  phenomenon 
{Gen.  Nova,  p.  67). 

When  Mr.  Ealfs  wrote  his  work  on  the  Desmidieae  (in  1848),  he  had  to 
confess  himself  altogether  ignorant  of  the  modes  of  reproduction  both  of 
Pediastrum  and  Seenedesmus.  He,  however,  described  self-di\ision  of  the 
cells  in  both  genera,  but  rightly  regarded  this  process  as  one  not  of  develop- 
ment, but  of  vegetative  increase  and  repetition.  On  this  subject  he  remarked 
{op.  cit.  p.  182), — "  I  have  not  seen  the  cells  duiing  the  process  of  division, 
but  I  am  informed  by  M.  de  Brebisson  that  it  takes  place  at  the  notch,  in 
the  same  manner  as  in  other  Desmidieae :  hence  the  cells  in  each  cii'cle  are 
connected  at  their  ends,  like  those  of  the  filamentous  genera.  I  do  not, 
however,  understand  in  what  manner  the  additional  circles  are  formed,  nor 
why  the  numbers  in  each  circle  are  so  constant." 

Niigeli,  likewise,  was  equally  ignorant  of  the  propagation  of  Pediastrum, 
but  thought  it  highly  probable  it  resembled  that  of  Seenedesmus.  The  num- 
ber of  cells  in  a  table  or  frond,  indicated  to  his  mind  its  production  by  a  series 
of  fissions  in  the  power  of  two ;  and  he  presumed  that  a  new  frond  was  gene- 
rated within  a  parent  cell  by  division  of  its  protoplasm,  just  as  in  Seenedesmus, 
— a  supposition  supported  by  the  fact  that  the  entire  young  fronds  are  not 
larger  than  the  single  cells  of  mature  specimens,  that  like  these  they  are 
composed  of  the  same  number  of  individual  cells  similarly  disposed,  and 
undergo  no  subsequent  segmentation  into  a  larger  number. 

The  more  recent  researches  of  Braun  are  confii^matory  of  the  views  of  Na- 
geli  (Gen.  Nova,  p.  68).  Amid  a  large  number  of  specimens  of  Pediastrum 
Boryanum  he  detected  the  escape  of,  in  most  instances  32,  more  seldom 
of  16,  and  rarely  of  8  gonidia,  from  a  parent  cell, — the  number  gene- 
rally, but  not  invariably,  corresponding  with  that  of  the  cells  composing  the 
matui-e  frond  or  coenobium.     The  collection  of  gonidia  was  enclosed  by  a 


30  GENEEAL  HISTORT  OF  THE  rN'FUSOEIA. 

common  envelope,  'witliin  whicli  they  moved  actively  about  for  a  quarter  of 
an  hour  before  coming  to  a  state  of  rest,  and  arranging  themselves  regularly 
in  a  frond  (I.  64).  This  sac  is  described  in  the  author's  work  on  Rejuvenes- 
cence {Bay  Soc.  p.  184)  as  the  vesicular  inner  layer  of  the  mother-cell. 
He  witnessed  this  production  of  gonidia  from  many,  but  not  from  all  the 
cells  of  the  fronds,  for  it  seems  to  take  place  in  them  in  succession,  and  pro- 
bably in  some  definite  manner,  according  to  theii'  position  in  the  frond.  He 
further  describes  the  development  of  microgonidia  to  follow  the  same  plan  as 
that  of  macrogonidia,  but  to  differ  from  the  latter  in  nimiber,  size  and  form, 
and  in  duration  and  cessation  of  motion.  Macrogonidia  have  a  subglobose 
figure,  a  diameter  of  y^th  of  a  millimetre ;  one  side  hyaline,  and  scarcely 
elongated,  the  other  tui^ned  towards  the  periphery  of  the  frond,  green,  and 
by-and-by  extended  and  emarginate :  no  vibratile  ciHa  discoverable  on  them. 
They  never  leave  the  sac  in  which  they  are  produced ;  and  the  yoimg  fi'ond  is 
seen,  until  the  close  of  the  second  day,  loosely  enveloped  by  a  gelatinous 
layer,  which  ultimately  disappears  by  deliquescence  (I.  64). 

On  the  other  hand,  microgonidia  are  at  fii'st  densely  aggregated  and 
closely  invested  by  the  sac  in  which  they  are  generated ;  like  macrogonidia 
they  are  subglobose  (I.  60,  61,  68,  69).  After  a  while  the  sac  is  gradually 
dilated,  and,  growing  more  and  more  in  length,  forms  an  acute  hyaline  beak 
{rostrum)  as  long  as  the  green  portion,  which  constitutes  the  rest,  or  the 
body,  of  the  gonidium.  This  rostrum,  moreover,  is  furnished  either  with  a 
pair  of  cUia,  longer  than  the  body,  or  with  a  single  cilium.  The  length  of 
these  developed  microgonidia  is  nearly  y^-o-th  millimetre  ;  the  thickness  -g-J-o  th 
(I.  61,  68,  69).  The  movement  within  the  sac  is  at  first  slow;  but  when 
this  is  fully  expanded,  it  is  very  active,  and  continued  for  an  hour  and 
upwards,  until  the  sac  is  ruptured,  and  the  Avhole  heap  of  microgonidia  escape. 
The  number  of  microgonidia  cannot,  by  reason  of  their  aggregation  and  their 
swarming  movement,  be  easily  determined ;  at  least  64  occur  in  a  sac,  and 
most  commonly  many  more,  for  instance,  128.  Of  theii'  subsequent  history, 
Braun  can  give  no  satisfactory  account. 

A  reference  to  the  same  able  writer's  book  on  Eejuvenescence  {R.  S.) 
informs  us,  at  p.  200,  that  before  the  formation  of  the  gonidia  of  Pediastrum, 
the  single  starch-grain,  the  nuclear  character  of  which  has  been  above  re- 
marked, disappears.  From  the  same  source  we  also  obtain  a  series  of  illus- 
trations of  the  development  of  macrogonidia,  of  their  arrangement  in  the 
characteristic  stellate  frondose  form,  and  of  the  varieties  in  the  number  and 
arrangement  of  the  component  cells,  which  may  be  seen  in  examples  of  the 
same  species  of  Pediastrum. 

The  development  both  of  Coelastrum  and  Sorastrum  is  unknown. 

The  Pediastrese  are  of  freshwater  habit,  living  in  ponds,  on  which  they 
frequently  form,  in  conjimction  with  other  small  plants,  a  coloured  film  or 
scum.  They  are  also  common  in  tm-fy  pools  on  moors,  and  invest  the  sui'face 
of  various  aquatic  plants. 

Systematic  Position  op  Pediastreje. — Mr.  Ealfs  followed  Ehrenberg, 
Meneghini,  and  others  in  placing  the  Pediastrese  among  Desmidiese ;  but 
Corda,  Nageli,  and  Braim  have  separated  the  two  as  distinct  tribes.  Indeed, 
Mr.  Ralfs  has  modified  his  views  since  the  publication  of  his  monograph,  and 
would  treat  the  Pediastreae  as  a  subfamily  of  Desmidiese.  Nageli  {Einzell.  Alg) 
arranges  them  with  the  PalmeUese  as  a  distinct  group,  and  in  this  has  the 
support  of  Braun  {Gen.  Nova,  p.  69).  These  natui'alists  point  out  that  the 
distinctive  features  between  the  Pediastreoe  and  the  Desmidiese,  are  that  the 
former  neither  conjugate  nor  miiltij)ly  by  continued  transverse  division  of  their 
cells  in  the  same  direction,  each  newly-formed  segment  acquiring  aU  the 


OF  THE  DIAT0MEJ2.  31 

characters  of  a  complete  cell ;  that,  iinlike  the  Desmidieae,  they  propagate  by 
gonidia;  have  but  one  instead  of  two  or  more  equally-sized  starch-grains 
and  a  central  nucleus ;  and  that  their  fronds  are  not  distinguishable  into  two 
symmetrical  halves.  ''  The  Desmidiese  are  e\idently  multicellular,  or  pseudo- 
unicellular,  from  separation  of  their  cells,  whilst  (says  Braun)  Pediastrum 
is  a  true  unicellular  Alga  rendered  pseudo-multicellular  by  the  cohesion  of  the 
cells.  The  aggregation  of  cells  in  Desmidieae  is  always  uniserial,  filiform  or 
concatenate ;  the  fronds  of  PediastriLm  are  grouped  on  a  plane  of  a  disc-form 
or  frondose  character." 

Braim  next  traces  the  affinities  of  Pediastrum,  and  remarks  that,  although 
it  resembles  Hydrodictyon  in  the  construction  of  its  fronds  (coenobia)  by  the 
connexion  of  motile  gonidia,  yet  since  in  Hydrodictyon  the  gonidia  are 
simultaneous,  and  in  Pediastrum  successional,  it  is  rather  an  analogy  than 
an  affinity  which  exists  between  these  two  genera.  However,  he  admits  the 
correctness  of  the  association  of  Pediastrum  with  the  genera  Nageh  indicated, 
viz.  with  Sorastnon,  Coelastrum,  Scenedesmus,  and  probably  Splicer odesmus, 
and  would  add  to  their  number  the  genus  Staurogonia  (Kiitz.),  the  Crucigenia 
of  Morren  {Ann.  des  Sciences  Nat.  1830,  p.  404).  All  these  genera  agree 
■with  Pediastrum  in  the  successional  formation  of  gonidia,  yet  differ  from  it 
in  other  particulars  except  in  the  construction  of  the  frond  from  motionless 
gonidia.  Among  other  genera,  Polyedrum  may  be  likened  to  Pediastrum  in 
the  form  of  its  cells,  but  its  propagation  is  unknown ;  lastly,  Characium  and 
Cystococcus  agree  with  Pediastrum  in  the  successional  genesis  and  activity  of 
their  gonidia. 

To  this  elucidation  of  the  affinities  of  Pediastrum  we  have  to  add  the 
observation  of  Cohn  (EntwicJc.  d.  miJcr.  Alg.),  of  the  analogy  or  affinity  in 
general  stnictiu-e  between  this  genus  and  Goyiium. 

The  di-^ision  of  Pediastrum  into  tribes  or  subgenera,  as  proposed  by  Braun, 
and  the  distinction  of  species  of  the  Pediastreae  in  general,  will  receive  due 
consideration  in  our  systematic  account  of  the  family. 

II.— OF  THE  FAMILY  DIATOMEJE  OR  DIATOMACEJE. 
(Plates  ly.  to  XYII.) 

General  and  External  Charactees  of  Diatome^. — Testules  or  Frus^ 
tides. — Figure  :  free,  concatenated,  and  fixed  Forms. —  VaHeties  of  Filaments 
and  of  Pedicels. — Aggregated  Frustules. — The  Diatomeae,  Diatomaeeae,  or 
CymbeUea?,  are  unicellular  organisms  composed  of  two  opposite  plates  or  valves, 
generally  convex,  and  of  an  interposed  connecting  thii'd  segment,  forming 
together  a  miniatui^e  box  of  a  silicious  nature,  enclosing  a  soft  organic  matter, 
rarely  green,  but  usually  yelloT\ish  or  orange-brown  in  colour.  They  inhabit 
either  fresh,  salt,  or  brackish  water. 

They  were  reckoned  by  Ehi'enberg  among  the  BaciUaria,  and  have  in  con- 
sequence been  sometimes  described  as  silicious  Bacillaria. 

Each  individual  Diatom  enclosed  in  its  silicious  envelope  is  spoken  of  as  a 
fi'ustule,  testule,  frond,  or  bacillum,  and  in  general  phraseology  as  a  cell. 
The  first  term  is  that  now  most  in  use,  whilst  "  testule  "  and  "  baciUum  " 
are  words  rarely  employed,  except  in  the  works  of  Ehrenberg  and  of  his  im- 
mediate disciples. 

A  rectangular  or  prismatic  figure  most  widely  obtains  in  this  family ;  and 
the  angles  of  jimction  of  the  valves  are  as  a  rule  acute.  Deeply  notched 
fronds,  like  those  in  Desmidieae,  e.  g.  Micrasterias  and  Euastrum,  do  not  occur ; 
and  the  production  of  spines  and  tubercles  on  the  valves,  so  common  in  that 
family,  is  rare  among  the  Diatomeae. 


32 


GENERAL  HISTORY  OF  THE  INFUSORIA. 


EiGURE. — There  is  an  immense  diversity  of  figure  among  the  frustiiles, 
determined  chiefly  by  that  of  the  opposed  valves,  but  in  some  degree  also  by 
the  amount  of  development  of  the  interposed  third  segment  or  eingulum 
(XYI.  23,  24.)  This  last  Mr.  Ralfs  considers  an  essential  part  of  every 
frustule ;  but  Prof.  Smith  states  it  to  be  a  secondary,  non-essential  element 
consequent  on  the  growth  of  the  organism,  and  specially  developed  .in  rela- 
tion to  the  process  of  self- division.  When  this  eingulum  or  "  connecting 
membrane  "  is  much  enlarged  prior  to  fission,  the  figui'e  as  viewed  on  this 
side  is  considerably  changed,  and  the  apj)earance  of  a  double  frastule  often 
occasioned. 

Not  a  few  of  the  Diatomese  are  much  elongated  and  narrow,  and  from  pre- 
senting a  wand-like  figui-e  (IX.  148,  166,  174 ;  X.  184,  185),  suggested  to 
Ehrenberg  the  term  Bacillaria  to  designate  the  family.  However,  some 
species  are  trapezoid,  or  square,  or  nearly  so  (X.  47,  21,  22),  others  round 
like  pill-boxes  (IX.  131,  181;  X.  200,  204),  whilst  others  again  are 
almost  globular  or  sj)heroid,  owing  to  the  great  convexity  of  the  valves. 
Several  genera  are  boat-shaped,  scaphoid,  or  navicular  in  figui-e  (IX.  139, 
135  ;  XII.  5,  6,  8,  48,  43) ;  some  are  mther  oval,  egg-shaped,  or  ovoid ; 
many  resemble  thin  flattened  discs — are  discoid  (XI.  33,  35,  36,  39); 
many  are  wedge-shaped — cuneiform,  or  cuneate  ;  a  few  are  triangular  (XI. 
43,  45)  ;  lastly,  some  are  curved  or  twisted  on  themselves,  and  others  assume 
in  certain  directions  a  sigmoid  or  an  undulated  figiu^e  (IX.  144, 145 ;  XV.  11, 
22,  59,  60).  Evenly-curved  valves  are  said  to  be  arcuate,  such  as  those  of 
Eunotia  (IX.  165;  XYI.  10,  18),  and  of  some  species  of  Cymhella  and 
Nitzschia,  whilst  the  peculiarly-twisted  valves  of  Campylodiscus  (XVII. 
517)  are  saddle-shaped.  In  Cymatopleura,  again,  the  surface  of  the  valves  is 
undulated,  and  when  bent  rather  sharply  at  an  angle  on  themselves,  the 
valves  become  geniculate,  as  in  Ach)ianthidium. 

As  a  rule  the  frustules  of  Diatomeae  are  sjrmmetrical,  and  consist  of  two 
equal  and  similar  halves ;  but  exceptions  to  this  are  found  in  the  Achnantheae, 
Cocconeidae,  and  one  or  two  other  families  (IX.  159). 

Another  variety  of  frustules  is  described  as  winged  or  alate, — the  ala  being 
a  smooth  expansion  in  the  form  of  a  margin  (XIII.  5,  6,  7).  The  alae  may 
arise  from  the  margin,  and  are  then  said  to  be  marginal,  as  in  Surirella,  or 
otherwise  from  the  disc,  as  in  Tryhlionella,  in  which  they  are  called  submar- 
ginal.  A  further  modification  of  the  valves  afiecting  the  figure  is  exemplified  in 
Nitzschia  and  AmpMprora,  which  have  a  longitudinal  elevated  ridge  extending 
from  one  extremity  to  the  other ;  such  ridges  are  called  keels,  and  the  valves 
keeled  or  carinated.  In  the  discoid  forms  two  portions  are  commonly  distin- 
guishable, viz.  the  disc  and  margin  or  rim  (XI.  31,  35,  38),  the  one  at  times 
separated  by  a  distinct  line,  and  often  presenting  different  sculpturing  from 
the  other.  The  disc  moreover  exhibits  occasionally  at  its  centre  a  promi- 
nence or  elevated  thickness  called  an  iimho  or  boss.  In  Eupodiscus  (XI.  41, 
42)  tubular  horns  come  off  from  the  surface  of  the  valves,  and  in  Triceratium 
from  the  angles. 

The  extremities  of  some  species,  e.  g.  in  Nitzschia  and  Pleurosigma,  are 
extremely  elongated,  forming  long,  filiform,  tubular  processes  ;  and  in  Den^ 
ticella,  Biddulphia  (II.  46,  48,  50),  and  RMzoselenia  (Ehi-.),  short  tubular 
processes  and  spines  are  produced  from  the  surfaces  and  margins.  These 
processes  are  commonly  simple,  but  according  to  Ehrenberg  are  branched 
(ramose)  in  the  genus  last  cited,  and  in  Dicladia  and  Syndendrium.  More- 
over, very  singular  hispid  and  sometimes  bifid  processes  or  styles  have  been 
noted  on  the  valves  of  some  species  of  Goniofhecium  (Ehr.),  recalling  by 
their  figure  that  of  the  spines  on  the  sporangia  of  many  Desmidieae.     Other 


OF  THE  DIATOME^.  33 

Diatoms,  referred  by  Mr.  Brightwell  {J.  M.  S.  1856,  p.  106)  to  the  geniis  CJice- 
toceros,  have  highly  developed  spines  on  the  valves,  besides  the  two  pairs  of 
very  long  filiform  smooth  or  spinous  horns  spiinging  from  the  fi'ustules 
themselves,  or  froin  the  interposed  cingulum.  Cerataulus  is  another  genus 
provided  with  a  pair  of  long  horn-like  processes. 

Great  variety  of  outline  may  prevail  in  a  genus,  so  considerable  indeed 
that  an  accurate  definition  is  mth  difiiculty  laid  doT^Ti,  the  characteristics 
shading  off  through  several  species,  untU  at  length  the  similarity  to  an  as- 
sumed typical  form  is  much  diminished,  whilst  on  the  other  hand  an  ap- 
proach is  made  towards  the  features  of  another  genus.  The  like  latitude  of 
form  prevails  also  with  species,  and  gives  rise  to  very  numerous  and  fre- 
quently perplexing  varieties.  On  this  topic  Prof.  Smith  remarks — '^  While 
a  typical  outline  of  its  frustule  is  the  general  characteristic  of  a  species,  this 
outline  may  be  modified  by  the  accidental  circumstances  which  smTound  the 
embryo  during  its  growth  and  the  development  of  its  sihcious  epiderm ;  then, 
any  such  aberration  of  form  becomes  stereotyped  by  the  process  of  self-divi- 
sion of  the  frustule,  generating  multitudes  of  others  slightly  deviating  from 
the  normal  form."  It  must  not  be  forgotten  that  the  figui'e  is  greatly  modified 
or  entu-ely  changed  by  the  position  of  the  valves,  whether  seen  in  face  or  on 
one  side ;  for  each  frustule  generally  presents  four  planes  or  sides,  and,  unless 
regard  be  paid  to  this  circumstance,  one  genus  may  be  mistaken  for  another, 
or  even  each  view  be  presumed  a  distinct  genus.  Thus  in  the  genera  Navicula, 
Pinnularia  (XII.  5,  6, 15,  18),  and  in  many  others,  the  frustules  are  on  one 
aspect  boat-shaped,  but  on  the  other  oblong  with  truncated  ends,  or  prismatic. 
In  the  genus  Triceratium  (XI.  43,  44),  the  difference  of  figure  is  very  re- 
markable according  to  the  side  viewed  (as  presently  illustrated).  It  is  there- 
fore necessary  to  examine  a  specimen  on  eveiy  aspect  it  presents :  this  can 
generally  be  effected  by  the  accidental  rolling  over  of  frustules  under  inspec- 
tion, or  can  otherwise  be  brought  about  by  a  very  slight  sliding  movement 
of  the  thin  glass  cover  upon  the  slide  under  the  microscope. 

Mr.  Brightwell  thus  describes  and  explains  the  transitions  of  form  produced 
by  a  change  in  position  of  the  frustules  of  the  genus  Triceratiuin  (J.  M.  S. 
i.  248)  : — "  The  normal  view  of  the  frustule  may  be  represented  by  a  vertical 
section  of  a  triang-ular  prism.  If  the  frustule  be  placed  upon  one  of  its  flat  sides, 
we  look  down  upon  its  ridge  and  obtain  a  front  view  of  its  two  other  sloping 
sides.  If  it  be  placed  upon  one  of  its  ridges,  we  have  a  front  view  of  one  of 
its  flat  sides,  generally  broader  than  long,  and  of  its  smooth  or  transparent 
suture  or  connecting  membrane.  If  the  frustule  be  progressing  towards 
self- division,  it  is  then  often  considerably  longer  than  broad,  and  when  nearly 
matured  for  separation  presents  the  appearance  of  a  double  frustule." 

It  would  be  in  vain  to  attempt  to  describe  all  the  numerous  forms  assumed 
by  the  members  of  this  extensive  family ;  the  representations  in  the  plates 
of  this  volume  will  convey  the  clearest  notions  of  their  diverse  outline  and 
markings  (see  Plates  4  to  17).  Great  difference  unfortunately  has  existed  re- 
specting the  sides  which  should  be  esteemed  primary  and  afford  specific  cha- 
racteristics, and  those  which  should  be  held  as  only  secondary;  and  the 
nomenclatui-e  of  the  surfaces  has  been  equally  a  matter  of  dispute  and  imcer- 
tainty.  Ehrenberg  employed  the  terms  dorsum,  venter,  and  lateral  surfaces 
or  sides,  but  so  loosely  that  they  do  not  always  Indicate  homologous  portions. 
Thus  he  has  often  called  a  convex  surface  the  dorsum,  simply  from  its  convexity, 
and  a  concave  one  the  venter,  on  account  of  its  concavity.  Kutzing  attempted 
a  more  certain  and  scientific  phraseology  by  calling  those  sides  which  have 
no  central  opening  (umbilicus),  but  through  which  self-di\ision  occurs,  the 
primary  sides,  and  the  other  two  the  secondary  sides,  further  distinguishing 

D 


34  GENERAL  HISTORY  OF  THE  INFUSORIA. 

the  latter  into  a  right  and  a  left  with  reference  to  the  frustule  when  lying  on 
a  primary  side.  The  left  side  is  often  concave,  and  the  right  convex ;  mostly, 
however,  the  two  are  alike.  As  a  general  rule  the  primary  sides  correspond 
with  the  lateral  surfaces,  and  the  secondary  with  the  dorsum  and  venter  in 
the  terminology  of  Ehi'enberg.  Mr.  Ralfs,  in  his  papers  in  the  Ann.  Nat. 
Hist.,  used  the  simple  terms '/>'on<  view^  and  ^  side  vieiu,'  corresponding 
respectively  T^ith  Kiitzing's  names  primary  and  secondary  sides.  The  Rev. 
W.  Smith  adopts  this  nomenclature  as  the  most  convenient  for  the  English 
student,  and  uses  the  term  'front  vieiu'  to  denote  the  aspect  of  the  frustule 
when  the  valvular  suture  (connecting  membrane),  or  the  line  along  which 
self-division  takes  place,  is  turned  towards  the  observer,  and  the  term  *  side 
vieiu^  when  the  centre  of  one  valve  is  dii-ected  to  the  eye.  He  adds — 
"  Even  these  terms  will  requii'e  modification  when  applied  to  some  of  the 
more  complex  and  irregular  forms ;  but  in  general  theii'  meaning  will  be 
sufficiently  obvious." 

It  must  happen,  therefore,  from  this  terminology,  that  at  times  a  front 
view  cannot  be  said  to  exist,  viz.  when  the  connecting  membrane  is  obsolete 
and  the  opposed  valves  are  closely  applied  to  each  other,  a  suture  alone  in- 
dicating the  line  of  junction. 

In  size  the  Diatomea)  vary  very  greatly ;  some  individual  frustules  are 
cognizable  by  the  naked  eye,  whilst  others  require  the  highest  powers  of 
the  microscope  to  display  them.  Even  among  specimens  of  the  same  species 
great  diversity  of  size  prevails, — a  peculiarity  much  determined  by  the  cii'- 
cumstances  surroimding  a  frustule  at  the  period  of  its  development,  and 
afterwards  perpetuated  through  a  long  series  of  individuals  multiplied  by 
self-fission. 

The  Diatomese  exist  under  three  chief  forms,  as — 1.  Single  isolated  free 
frustules.  2.  Frustules  attached  by  a  stalk,  stij^es,  or  pedicle.  3.  Frustules 
coherent  in  chains,  or  aggregated  together  in  ramose  tufts  by  an  interposed 
gelatinous  substance.  The  third  form  is  the  consequence  of  incomplete  fission, 
or  of  imperfect  separation  after  fission.  Incomplete  fission  and  consequent 
concatenation  are  observed  in  Bacillaria,  Meridion,  Himantidi^mi,  Melosira, 
Odontidium,  Striatella,  Fragilaria,  &c.  (IX.  131,  167,  171,  175,  176,  177) ; 
and  the  form  of  the  chain  or  filament  produced  -^-ill  be  determined  by  the 
figiu^e  of  the  indi^-idual  frustules  composing  it.  For  instance,  if  these  be 
rectangular,  then  the  resulting  chain  (IX.  171,  172,  176 ;  XIV.  2,  4,  6,  la) 
is  straight,  but  if  wedge-shaped,  it  is  cun-ed  or  spiral  (IX.  177,  179 ;  XII. 
21).  The  extent  and  degree  of  attachment  of  the  adjoining  frustules  difier 
in  difierent  genera ;  thus,  in  Bacillaria  it  is  very  shght,  and  readily  yields, 
allowing  one  segment  to  glide  on  another,  or  to  separate  from  it,  except  at 
one  point,  yet  at  the  same  time  possessing  the  power  of  recovering  itself.  In 
Odontidium,  Himantidium,  Denticida,  and  Meridion  (IX.  177),  the  mutual 
adhesion  of  the  several  segments  is  stronger ;  and  after  the  opposed  sui-faces 
have  been  separated,  futiu^e  adhesion  is  not  effected.  In  Fragilaria,  the  ad- 
herence is  more  tenacious.  In  Diatoma,  Tahellaria,  Ghr(mmatoj)7iora,  Am- 
phitetras,  &e.  (II.  46 ;  XI.  22,  52 ;  XIV.  23),  the  frustules  hang  together  by 
a  sort  of  hinge  inserted  between  adjoining  angles  in  a  zigzag  fashion.  In 
IstJimia,  this  hinge  or  connecting  link  attains  a  greater  magnitude,  and,  in 
fact,  is  double.  In  Podosira  (II.  45)  and  in  some  species  of  Melosira  a 
junction-process  is  developed  from  the  centre  of  each  frustule  in  the  chain. 
In  other  Melosirce  and  in  OrtJiosira,  the  junction-siufaces  are  toothed  (den- 
tate), and  thus  hold  the  adjoining  frustules  in  firm  union.  In  the  instance 
of  Biddidpliia  (II.  46,  48),  the  siufaces  in  union  are  curiously  elongated  at 
the  angles  into  rounded  or  horn-like  processes,  whilst  theii'  convexity  is 


OF  THE  DIATOME^.  35 

crowned  bj^  several  bristles  or  setae.  Lastly,  in  Eiicainpia  (II.  48)  the 
junction-surfaces  are  so  excavated,  that  when  the  frustules  are  concatenated  a 
filament  is  formed,  perforated  by  oval  foramina. 

In  not  a  few  genera,  as  above  mentioned,  the  attachment  is  at  opposed 
angles,  and  a  zigzag  chain  produced ;  but  in  Istlimia  (X.  183)  it  is  peculiar 
in  being  indiscriminately  made  at  any  part  of  the  adjacent  frustule,  and 
thereby  produces  an  iiTcgularly  branched  filament. 

The  above  examples  will  suffice  to  illustrate  the  characters  and  varieties 
of  concatenation  in  the  form  of  filaments,  whether  straight  or  spiral ;  but  it 
is  necessary  to  add  that  the  width  of  a  filament  "  equals  the  length  of  the 
frustule  or  valve  measured  along  the  suture  or  junction-line,  and  that  the 
breadth  of  the  valve  denotes  the  thickness  of  the  filament "  (Smith,  Synojos. 
ii.  6).  In  those  instances  in  which  frustules  are  connected  together  by  a 
process  or  small  isthmus  acting  as  a  sort  of  hinge,  the  concatenation  cannot 
be  ascribed  to  incomplete  division  only,  for  the  existence  of  such  a  process  is 
the  result  of  a  special  formation  which  essentially  coiTesponds  with  the 
pedicle  or  stipes  of  fixed  species. 

Numerous  Diatomese  grow  attached  to  foreign  bodies  by  a  stalk  of  variable 
length,  and  which,  although  generally  simple,  is  sometimes  comjDound  by 
dividing  and  subdividing  in  a  ramose  manner.  Even  among  the  recognized 
free  Diatomeae,  such  as  Navicula,  Pinnularia,  Nitzscliia,  &c.,  specimens  are 
not  unfrequently  seen  adherent  by  one  extremity,  about  v>^hich  they  turn 
or  bend  themselves  as  on  a  hinge ;  however,  in  these  instances  such  union 
is  but  temporary,  and  no  connecting  medium  exists.  In  Synedra  (X.  184), 
on  the  other  hand,  a  bond  of  union  occurs  in  the  form  of  a  little  gelatinous 
conical  nodule,  resembling  very  nearly  the  hinge-like  isthmus  which  binds  to- 
gether the  frustules  of  many  genera  in  a  sort  of  zigzag  chain.  By  the  process 
of  self- division  it  also  comes  to  pass  that  groups  of  Synedrce  occiu'  attached 
together  by  the  same  point,  in  a  fan-like  or  a  stellate  form,  as  in  S.  radians, 
S.  affinis,  &c.  In  other  species  detachment  after  fission  is  too  speedy  to 
allow  of  this  sort  of  combination,  except  of  some  two  or  four  indi\dduals. 
The  fan-like  collection  of  frustules  is  said  to  be  flabellate,  fan-like,  or 
radiating ;  and  when  the  component  members  are  curved,  they  and  the  bun- 
dles they  form  are  described  as  arcuate.  The  nodule  of  attachment  occurs 
in  various  degrees  of  development,  and  attains  in  this  same  genus  Synedra  to 
the  dimensions  of  a  pedicle — ex.  in  Synedra  sujperba,  and  even  to  branch, 
as  in  Synedra  fulgens  and  Synedra  pidcJielJa. 

^Tien  a  stipe  branches,  it  does  so  normally  in  a  dichotomous  manner  by 
the  very  circumstance  of  the  process  of  self- division,  each  new  individual 
produced  by  that  act  developing  its  o"v\ti  secondary  pedicle,  or  pedicel. 

This  regular  dichotomy  is  instanced  in  the  genera  Dorypliora  (XIV.  21), 
Cocconema  (XIII.  10),  and  Gomphonema  (XIII.  11).  In  Licmopliora  (XIII. 
20),  and  in  one  species  of  Rhiindoijliora,  viz.  Rh.  Dalmatica,  an  irregular 
branching — essentially  dichotomous,  however — is  met  with,  and  is  thus  ex- 
plained by  Prof.  Smith : — "  In  Rhipidophora  paradoxa  and  Rh.  elongata, 
self- division  is  immediately  followed  by  the  separation  of  the  half-new  frus- 
tules and  a  dichotomy  in  the  filamentous  stipes,  while  in  the  present  genus 
the  frustules  remain  for  a  time  coherent,  and  continue  dividing  and  mul- 
tiplying on  the  summit  of  the  pedicel,  which  becomes  elongated  and  incras- 
sated  at  each  successive  repetition  of  the  process ....  A  branching,  or  rather 
longitudinal  rupture,  of  the  pedicle  takes  place  at  irregular  intei^als ;  and  the 
entire  organism  presents  us  with  more  or  less  complete  flabeUa  (fan-like 
clusters)  on  the  summit  of  the  branches,  and  imperfect  flabeUa  or  single 
frustules  irregularly  scattered  throughout  the  entire  length  of  the  pedicel." 

B  2 


36  GENEKAL  HISTORY  OF  THE  INFUSORIA. 

The  same  authority  has  the  following  remark  on  the  process  of  ramification : 
he  says  (i.  75),  "  When  self-division  {i.  e.  of  the  frustules)  is  completed,  the 
extension  of  the  filament  below  the  fnistules  is  suspended,  a  joint  or  arti- 
culation is  formed  at  the  base  of  the  dividing  frustule,  and  each  of  the  half- 
new  frustules  begins  anew,  in  its  progress  towards  special  self- division,  the 
secretion  of  a  new  joint  or  internode ;  and  a  dichotomy  is  the  result." 

The  occurrence  of  the  double  condition  of  union  of  frustules  in  a  con- 
catenate manner  and  of  attachment  by  a  pedicle  is  illustrated  in  the  genera 
Achminthes  (X.  201,  202),  Striatella  (X.  203, 204),  BhabcJonema  (XIII.  27), 
and  Podosira  (II.  45).  In  Melosira  also,  attached  species  occur ;  and  Prof. 
Smith  inclines  to  the  opinion  that  all  filamentous  Diatomese  are  stipitate  on 
their  first  production.  In  the  second  stalked  genus  cited,  viz.  Striatella,  the 
stalk  attains  the  highest  development,  but  remains  slender  and  unbranched. 
Between  this  most  developed  foim  and  the  mere  nodules  of  attachment  in  the 
genera  Achnanthes  and  Melosira,  every  intermediate  phase  is  encountered. 
In  any  one  species,  however,  there  is  no  positive  determinate  length  of  the 
stipes,  for  this  varies  according  to  the  idiosyncrasy,  vigour,  and  external  con- 
ditions affecting  the  organism;  consequently  characters  derived  from  the 
dimensions  of  the  stems  can  have  no  specific  value. 

There  is  a  large  section  of  Diatomeae  in  which  the  frustules  are  diffused 
throughout  a  mucous  or  muco- gelatinous  mass,  rarely  confusedly,  but  mostly 
in  a  definite  manner,  usually  in  thread-  or  tuberlike  branches,  which  nor- 
mally ramify  in  a  dichotomous  fashion,  and  resemble  on  a  minute  scale  the 
tufts  formed  by  many  large  sea-weeds.  This  peculiar  aggregation  is  the 
consequence  of  the  large  production  and  subsequent  persistence  of  the  mucus 
which  is  thro^Ti  out  when  the  system  of  reproduction,  whether  by  sporangia 
or  by  fission,  takes  place.  Histologically,  therefore,  it  is  homologous  with 
the  pedicles  and  connecting  nodules  or  isthmi  thrown  out  duilng  the  act  of 
seK-division,  as  also  with  the  mucous  stratum,  which  still  very  often  persists 
when  that  act  is  complete,  around  specimens  of  Cocconeis,  Chcetoceros,  Melo- 
sira, Fragilaria,  Striatella,  &c. 

The  tissue  thus  composed  of  mucus  and  enclosed  frustules  constitutes  what 
is  called  (from  analogy  with  the  large  Algae  and  other  Crj^togamic  plants) 
the  frond,  and  affects  various  shapes,  in  some  measure  characteristic  of  the 
genera.  Thus,  in  one  of  those  so-called  frondose  Diatomeae,  viz.  DicMeia 
(XY.  30,  31),  it  is  membranous  and  leaf-like,  and  resembles  a  species  of 
IJlva;  in  Mastogloia,  filiform  with  nipple-like  expansions;  in  Encyonema 
(XIV.  22),  Homceocladia  (XIY.  37,  38,  47,  49),  and  Sehizonema,  filamentous 
and  more  or  less  branched ;  in  Colletonema  suhcohcerens,  globose.  Again,  when 
filamentous,  the  ramifications  differ  much  in  thickness  and  in  expansion,  and 
in  the  extent  of  adhesion  between  the  branches ;  where  these  are  long  and 
slender  they  are  called  '  capillary,'  and  where  contiguous  branches  coalesce, 
they  give  rise  to  a  submembranous  condition.  The  degree  and  mode  of 
division,  the  collection  of  the  branches  into  bundles  (i.  e.  fasciculi),  or,  on  the 
contrary,  their  loose  or  diffuse  arrangement,  supply  useful  characters  in  the 
distinction  of  species.  Again,  the  fronds  differ  in  consistence,  being  in  some 
genem  or  species  more  rigid,  setaceous,  or  robust,  in  others  softer,  flaccid, 
and  more  delicate  :  these  opposite  conditions  furnish  Prof.  Smith  with  grounds 
for  the  division  of  the  genus  Sehizonema  into  two  tribes. 

The  disposition  of  the  fi^ustules  within  the  mucous  investment  supplies 
other  important  distinctions.  Thus  in  DicMeia  it  is  irregular ;  in  Mastogloia 
each  little  frustule  occupies  ''  the  summit  of  a  little  nipple-Hke  cushion  of 
gelatine ; "  in  BerTceleya  (XIV.  34,  35)  the  frustules  are  densely  packed  in 
the  filaments ;  in  Encyonema   they  occur   mostly   "  in    single   file,    except 


OF  THE  DIATOME^. 


37 


towards  the  extremities,  where  they  are  somewhat  crowded"  \vithin  the 
distinctly  tubular  filaments,  and  enjoy  a  certain  latitude  of  movement ;  and, 
lastly,  in  Colletonema  and  Schizonema  (X.  207,  208)  they  are  arranged 
in  one  or  more  files  according  to  the  stage  of  growth,  within  less  per- 
fect tubes  than  in  the  genus  last  mentioned,  and  retained  in  situ  by  the 
mucus  around. 

Ehrenberg  recognized  this  tribe  of  compound  Diatomese,  and  introduced  it  as 
one  of  the  sections  of  his  great  family  Bacillaria,  under  the  name  of  Lacerifuita, 
or  Naviculce  with  a  double  lorica.  His  acquaintance  with  the  group  was,  how- 
ever, very  imperfect,  and  he  appears  to  have  comprehended  in  it  organisms 
quite  foreign  to  it,  and  to  have  failed  to  give  that  precision  to  his  classifi- 
cation of  the  included  beings  which  could  alone  confer  a  high  scientific  value 
and  permanence  upon  it. 

Of  the  Eitvelopes  of  the  Feustules  of  DiATOiiEJE. — The  Silicioiis  Shell  or 
Lorica  ;  its  Divisions  and  Structural  Comiwsition,  Markings,  Strict,  Canali- 
culi,  Pumta,  ^c.  —  Sufficient  has  been  said  of  the  mucous  coat  which  at 
certain  times,  and  always  in  certain  genera,  surrounds  the  frustules  of 
Diatomese.  The  frustules  themselves  remain  to  be  described:  they  are 
hollow  variously-shaped  cells  having  but  one  cavity — unicellular,  and  a 
siUcious  outer  wall,  unafi'ected  by  a  red  heat  and  by  strong  acids,  which 
would  corrode  and  dissolve  every  other  substance  belonging  to  a  living  being 
except  silex.  This  silex  is  stated  not  to  polarize  light,  as  does  the  mineral 
silex  not  in  combination  with  organic  beings ;  and  the  erroneous  statement 
made  by  some  authors,  of  the  polarizing  effect  of  some  Diatomaceous  shells 
is  due  to  the  circumstance,  that  they  did  not  take  care  to  thoroughly  remove 
the  organic  carbonaceous  matter  with  which  the  silex  is  in  union  in  the 
fnistides  in  question. 

The  silex,  besides  being  united  with  organic  matter,  deposited  it  may  be 
within  a  cellular  tissue,  is  contaminated  by  iron,  which  Professor  Frankland 
of  Manchester  states  {Smith,  Synops.  p.  xxi)  *' exists  in  the  state  of  a 
silicate  or  protoxide  .  .  .  .  "  and  he  attributes  to  its  presence  "  the  brown  colour 
which  is  assumed  upon  exposing  the  Diatoms  to  the  influence  of  a  moderate 
heat;  the  protoxide  of  iron,  by  the  gradual  absorption  of  oxygen,  being 
converted  into  brown  peroxide  of  iron,  which  assumes  a  redder  tinge  upon 
being  more  strongly  heated." 

The  relative  proportion  of  silica  varies  within  considerable  limits  in  different 
genera  of  Diatomeae.  In  several  genera,  perhaps  in  marine  ones  exclusively, 
it  is  very  deficient,  and  the  wall  of  the  frustule  is  httle  more  than  horny,  or  it 
may  be  even  flaccid,  as  for  example  in  Dichieia  and  Schizonema.  The  frustules 
of  Fragilaria,  Striatella,  and  Poclosira  are  less  firmly  sihcious  than  those  of 
many  others  of  the  filamentous  Diatomese.  In  some  genera  (those,  viz., 
which  produce  tubular  processes)  silex  is  deficient  or  absent  from  the  pro- 
duced wall ;  in  Poclosira  this  deficiency  occurs  at  the  apex  of  the  valves,  and 
in  Prof.  Smith's  opinion  is  probably  intended  "to  allow  a  free  secretion  of 
the  mucus  which  unites  the  frustules  and  provides  a  pedicle  for  their  attach- 
ment to  the  plant  on  which  they  grow,  as  it  does  not  occur  on  the  non- 
attached  valve  of  the  fii^st- formed  frustule.  In  the  Hving  state  the  absence 
of  silex  is  not  perceived;  but  when  the  frustules  have  been  macerated  in 
acid,  these  portions  of  the  valves  appear  as  perforations,  owing  to  the  dis- 
appearance of  the  ceU-membrane." 

The  frustules  of  the  Diatomeae  are  composed,  as  before  stated,  of  two 
usually  more  or  less  convex  valves,  enclosing  a  single  cavity,  which  becomes 
augmented  by  the  growth  of  a  third  segment  interposed  between  them,  pro- 
duced preparatory  to  the  process  of  self-division.     Meneghini  asserts  that 


38  GENEEAL  HISTORY  OF  TfiH  INFUSOEIA. 

the  silicioiis  sMeld  or  lorica  is  four-sided,  and  composed  of  four  pieces  or 
valves.  Although  this  appears  to  be  the  true  stnictm-e  of  some  species,  omng 
to  the  ready  separation  of  the  connecting  membrane  into  two  portions,  yet  the 
majority  oifer  no  countenance  to  the  notion,  the  connecting  membrane 
forming  a  continuous  oval  or  circular  ring.  In  Triceratium,  however,  is  an 
example  of  an  even  more  pseudo-multiple  composition ;  for  its  prismatic  tri- 
angular frustule  breaks  up  into  "  two  triangular  plates  or  walls  of  silex 
forming  the  ends,  and  into  three  oblong  rectangular  pieces  or  bands  forming 
the  three  sides,  the  latter  usually  dividing  themselves  into  several  elongated 
paralleliform  pieces"  (Brlghtivell,  J.  M.  S.  i.  248). 

Again,  in  several  genera,  doubtfully  arranged  by  Ehrenberg  among  the 
siHcious  Bacillaria,  e.  g.  Dictyocha  (XII.  62,  63)  and  Mesocena  (XII.  71),  the 
individuals  are  represented  as  composed  of  several  segments  united  together. 
Each  valve  consists  of  a  sihcious  lamina  supei-posed  on  an  organic  soft 
lining  (or  primordial)  membrane  which  immediately  encloses  the  contents  of 
the  cell.  Nageli  speaks  of  a  mucilaginous  peUicle  on  the  inside  of  the 
organic  layer  as  a  sort  of  third  tunic ;  and  Kiitzing  likewise  discovers  a  thin 
stratum  brought  into  view  when  recent  frustules  are  dried,  and  particularly 
after  heating  them  to  redness,  in  the  shape  of  an  opake  bro^vnish  stain,  or 
of  brown  hues  or  points,  extending  not  unfrequently  over  a  considerable 
portion.  To  this  supposed  independent  material  its  observ^er  applied  the 
name  '  cement/  imagining  it  to  be  the  connecting  matter  of  the  valves  and 
of  frustules  when  in  luiion,  and  attributed  its  bro^Ti  colom^  to  the  presence 
of  ii'on.  This  presumed  layer  of  cement  we  can  regard  as  nothing  more  than 
the  stain  produced  by  the  oxidation  of  the  salts  of  iron  in  chemical  union 
■with  the  silica,  as  Prof.  Erankland  has  shown  (p.  37).  However,  Meneghini 
adopts  the  notion  of  this  third  envelope  or  cement,  inasmuch  as  he  observes 
it  to  be  constant,  without  employing  the  means  used  by  Kiitzing  to  display 
it,  not  merety  in  the  species  enumerated  by  its  discoverer,  but  in  many 
others,  and  possibly  in  all  (R.  S.  1853,  p.  361) : — "  Por  to  me  (continues  the 
same  author)  it  appears  to  correspond  with  that  fine  membrane  of  the  Ach- 
nanthidia,  which,  according  to  Kiitzing's  o^^ti  observation,  is  always  \isible 
whenever  the  two  new  individuals  (into  which  every  Diatom  is  resolved  in 
its  multiplication  by  deduplication)  begin  to  separate.  The  lines  and  points 
supposed  to  belong  to  the  subjacent  shield  belong  very  frequently  to  this  kind 
of  covering."  The  analogy  expressed  in  the  quotation  just  given,  between 
the  delicate  stratum — the  '  cement '  of  Kiitzing,  and  the  secretion  poured 
out  when  self-division  is  proceeding,  we  cannot  regard  as  correct ;  for  this 
latter  is  a  special  and  usually  not  persistent  coating,  in  all  j)robability  exuded 
through  the  fissui^es  or  pores  uncovered  by  the  silieious  lamina,  by  the  sub- 
jacent organic  membrane,  and  is  T\dthal  destroyed  by  the  heat  generally 
required  to  brmg  the  '  cement '  into  view,  whereas  the  presumed  coat  is 
represented  to  be  constant  and  also  permanent  both  under  the  operation  of 
fire  and  of  acids.  However,  the  belief  in  the  existence  of  a  vegetable  mem- 
brane outside  the  silieious  epiderm  gains  ground ;  for  Mr.  Shadbolt,  in  his 
presidential  address  before  the  Microscopical  Society,  1858  {T.  M.  S.  1858, 
p.  72),  states  it  as  the  result  of  his  researches,  that  the  frustule  of  Arach- 
noidiscus  and  of  other  forms  consists  of  a  silieious  frametvorJc,  over  which  is 
stretched  a  species  of  membrane,  whether  silieious  or  not  he  does  not  presume 
to  decide,  but  certainly  pliant  to  a  considerable  extent,  capable  of  being  par- 
tially rolled  up  by  mechanical  agency  without  breaking,  and  elastic  enough 
to  return  to  its  original  position  when  the  extraneous  force  is  removed. 
"  The  structiu-e  noticed  by  Mr.  Eoper  in  Coscinodiscus  Jahyrinthus,  and  by 
myself  in  the   more  common  species  C.  radiatus  and  Triceratium  favxis,  I 


OF  THE  DIATOME^.  39 

believe  to  be  of  precisely  the  same  nature,  and  I  am  much  mistaken  if  we  do 
not  find  it  in  many  other  species  of  the  Diatomacea." 

In  the  accompanying  part  of  the  Jom-nal  {J.  M.  S.  1858,  p.  162),  Prof. 
"Walker- Arnott  refers  with  approval  to  this  opinion  of  Mr.  Shadbolt,  and 
appends  some  most  important  remarks  bearing  on  the  presence  or  absence  of 
this  membrane  in  the  determination  of  species.  He  observes  that  "  There 
can  be  no  doubt  that  these  discs  (i.  e.  of  A^mchnoidiscus)  have  a  horny 
vegetable  outer  covering,  in  addition  to  the  siHcious  one,  and  that  by  too 
long  boiling  in  acid,  as  is  necessary  for  guano,  the  marks  are  much  obli- 
terated or  entirely  removed.  This,  however,  is  not  peculiar  to  the  present 
genus,  but  may  be  observed,  more  or  less,  in  all  Diatoms,  although  sometimes 
the  vegetable  pellicle  is  very  thin  and  may  be  removed  by  a  few  seconds' 
immersion  in  boiling  nitric  acid.  It  is  this  circumstance  which  gives  a  quite 
different  appearance  to  the  same  species,  according  as  the  preparation  is 
made.  Thus,  in  Actinocydus  the  vegetable  epidermis  is  cellular,  while  the 
silicious  part  is  striated  like  a  Pleurosigma  ;  and  when  the  vegetable  part  is 
removed,  we  often  find  nodules  or  knobs  along  the  margin  (forming,  then, 
the  genus  Omj^halojyelta),  not  previously  visible.  Those  who  describe  Diatoms 
from  slides  are  thus  liable  to  commit  great  errors,  and  indeed  no  certainty  can  be 
obtained,  except  by  getting  the  recent  or  growing  Diatom  and  examining  it, 
1st,  after  being  immersed  for  a  short  time  in  cold  acid,  or  simply  washed  in 
boiling  water ;  2ndly,  after  being  boiled  in  acid  for  about  half  a  minute,  or  a 
whole  minute  at  most ;  and  Srdly,  after  being  boiled  for  a  considerable  time : 
we  shall  then  see  that  many  of  the  supposed  distinct  species  of  authors  are 
the  same,  prepared  in  a  different  way.  Of  course,  deposits  or  guanos  can  yield 
little  or  no  information,  although,  when  once  a  species  has  been  determined 
by  the  way  I  have  indicated,  we  may  be  able  to  refer  forms  occurring  in 
guano  or  deposits  to  it  with  tolerable  certainty." 

Mr.  Brightwell,  speaking  of  the  lorica  or  silicious  epiderm  of  Triceratmnij 
states  that  the  valves  are  resolvable  into  "  several  distinct  layers  of  silex, 
dividing  like  the  thin  divisions  of  talc,  and  frequently  found  of  such  exquisite 
delicacy  as  to  be  difficult  of  detection"  (J.  M.  S.  i.  248).  The  siHcious  lamina 
is  generally  looked  upon  as  a  production  or  secretion  fi'om  the  subjacent 
organic  membrane,  the  true  cell-waU.  NageU  (B.  S.  Rejports,  1846,  p.  220) 
says,  "  it  lies  outside  the  membrane,  and  must  be  regarded,  from  analogy 
Avith  aU  other  similar  structures,  as  an  extra- ceUular  substance  excreted  from 
the  ceU;"  and,  as  Meneghini  {op.  cit.  p.  360)  adds,  "in  fact,  anorganic  mem- 
brane ought  to  exist,  for  the  silica  could  not  become  solid  except  by  crystal- 
lizing or  depositing  itself'  on  some  pre-existing  substance."  Prof.  Smith 
moreover  states  (A.  N.  H.  1851)  that,  apart  from  analogy,  he  has  direct  evi- 
dence of  the  independence  of  the  silicious  coat,  having  in  his  possession 
numerous  specimens  of  a  Stauroneis  (probably  S.  aspera,  Kiitz.),  in  which  the 
valves,  after  slight  maceration  of  the  fnistules  in  acid,  have,  in  part  or  wholly, 
become  detached  fi'om  the  ceU- membrane,  leaving  a  scar  on  its  walls  bearing 
the  distinct  impression  of  the  numerous  and  prominent  valvular  markings  of 
this  beautiful  species.  The  same  observer  adds  that  he  has  in  some  cases 
noticed  this  organic  membrane  to  contract  around  the  ceU-contents,  upon  the 
death  of  the  ceU.  Again,  the  application  of  hydrofluoric  acid,  proposed  by 
Prof.  Bailey,  to  recent,  and  sometimes  even  to  fossil  shells,  proves  the  same 
fact,  by  leaving  a  distinct  internal  flexible  ceU-membrane  retaining  the 
general  form,  after  the  dissolution  of  the  siHca  by  the  acid.  Further  support, 
if  needed,  is  furnished  by  the  phenomena  of  cell-division,  in  which  the  lining 
membrane  takes  the  initiative,  and  is  foUowed  by  the  doubling-in  of  the 
external  coat  upon  it. 


40  GENEEAL  HISTORY  OF  THE  INFUSOEIA. 

Nevertheless,  although  a  silicioiis  layer  be  artificially  separable  from  the 
underlying  organic  coat,  the  relation  and  union  of  the  two  are  indeed 
very  intimate  :  and  in  the  case  of  the  apparently  inorganic  external  lamina, 
the  silex  must  be  presumed  to  be  deposited  in  some  form  of  connective  tissue, 
or,  in  other  words,  to  permeate  it.  This  opinion  is  advocated  by  Meneghini, 
who  adduces  in  its  support  the  circumstance  of  the  sihcious  shield  of  Ach~ 
nanthidia  being  covered  with  "a  very  delicate  dilatable  membrane,  itself 
containing  silica,  as  is  proved  by  its  sustaining  imchanged  the  action  of  fire 
and  acids."  This  author  goes  on  to  suggest  that  "this  permeation  may 
occur  either  in  the  wall  of  a  simple  cell,  as  is  seen  in  the  epidermal  cells  of 
many  plants,  or  within  minute  cells,  as  in  various  plants  and  animals." 

The  surface  of  Diatomaceous  frustules  is  generally  very  beautifully  sculp- 
tured, and  the  markings  assume  the  appearance  of  dots  (pimcta),  stripes 
(striae),  ribs  (costae),  pinnules  (pinnae) ;  of  furrows  and  fine  lines ;  of  longi- 
tudinal, transverse  and  radiating  bands ;  of  canals  (canalicuh),  and  of  cells 
or  areolae,  whilst  each  and  all  these  varieties  present  striking  modifications 
in  number,  relative  distribution,  and  in  degree  of  development.  Again,  two 
or  more  sorts  of  markings  may  occur  together  in  the  same  individual ;  and 
lastly,  the  entire  frustule  may  be  covered,  or  certain  spots  may  be  left 
unoccupied  by  them,  in  the  form  of  bands,  circular  spaces,  and  the  like. 

The  preceding  accoimt  of  the  coverings  of  a  Diatomaceous  frustule  make  it 
clear  that  the  apparent  superficial  markings,  although  chiefly  due  to  the 
sculpturing  of  the  silicious  epiderm  and  to  its  internal  involutions,  are  still 
in  some  instances  and  in  a  certain  degree  dependent  on  the  overlying  firm 
vegetable  membrane  which  Mr.  Shadbolt  and  others  have  shown  to  exist. 

But,  apart  from  this,  modem  research  shows  that  puncta,  lines,  costae  and 
other  markings  are  not  the  same  in  nature  in  all  examples  presenting  them ; 
that  in  one  case  a  circular  point  is  a  depression,  in  another  an  elevation,  and 
in  a  third  a  mere  thickening  or  condensation  of  silicious  material.  So 
of  lines  or  costae:  some  are  markings  of  the  surface,  and  either  furrows, 
ridges  or  thickenings,  or  actual  canals,  whilst  others  are  the  result  of  invo- 
lutions or  foldings  of  the  internal  coat  or  incomplete  septa. 

Again,  the  fine  lines  or  striae  of  many  frustules  are  resolvable  into  rows  of 
minute  dots,  as  in  Navicula  and  Pleurosigma.  When  the  striae  are  more 
distinctly  composed  of  rows  of  dots  or  puncta,  they  are  described  as  monili- 
form ;  examples  occur  in  Gomplionema  and  Podosphenia. 

Speaking  of  striae,  lines,  and  puncta  generally.  Prof.  Smith  {op.  cit.  i. 
p.  xvii)  confesses  his  belief  that  they  are  all "  modifications  in  the  arrangement 
of  the  silex  of  the  valve,  arising  from  the  mode  of  development  peculiar  in  each 
case  to  the  membrane  with  which  the  silex  is  combined ;"  and,  referiing  to 
the  areolar  or  cellular-looking  valves  of  Triceratium  and  of  Isthmia  especially, 
and  to  the  recognized  growth  of  organized  beings  by  cells,  he  arrives  at  the 
conviction  that  "  the  valvular  markings  in  every  case  arise  from  modifications 
of  cellular  tissue,"  which  forms,  so  to  sjDeak,  the  matrix  of  the  silicious 
epiderm.  "  No  difficulty  (he  adds)  presents  itself  to  the  suj^position  that  the 
moniliform  striae  of  Epithemia,  Navimda,  and  others,  the  circular  markings  of 
Coschiodiscus  eccentricus,  and  the  iiTegular  star-like  stiTictiu'e  of  Eupodiscus 
Argus,  are  aU  modifications  of  cellular  tissue ;  and  even  in  the  costas  of  Pin- 
nularia,  and  the  unresolvable  striae  of  Eupodiscus  sculptus  and  others,  it  is 
not  difficult  to  conceive  we  have  confluent  cells  whose  union  gives  rise  to  the 
appearance  of  lines  or  bands." 

Great  difi'erence  has  existed,  and  even  yet  exists,  in  the  interpretation  of 
the  exact  nature  of  many  superficial  markings.  Some  cuTular  dots  or  puncta 
are  held  by  certain  observers  to  be  pits,  by  others  holes,  and  by  others  to  be 


OF  THE  DIATOME^.  41 

elevations.  So  of  stripes,  costoe,  and  pinnules :  to  some,  such  markings  in 
special  instances  are  ridges  ;  to  others,  furrows  or  fissures  ;  to  others,  ele- 
vations ;  and  to  others  again,  canals.  The  ardent  microscopical  research  of 
this  period  is  daily  diminisliing  the  number  of  these  enigmas,  and  intro- 
ducing certainty  in  place  of  doubt  and  vague  conjecture.  To  Ehrenberg's 
apprehension,  many  puncta  were  real  pores,  and  many  striae  or  costse  real 
fissures  ;  the  former  of  these  were  supposed  to  give  exit  to  a  few  or  to  multi- 
tudinous imaginary  '  pedal  organs '  for  locomotion,  the  latter  to  serve  for  the 
passage  of  ova,  and  generally  to  bring  the  presumed  internal  animal  organiza- 
tion into  immediate  relation  with  the  external  medium  around  it. 

Perhaps  the  discussion  respecting  the  nature  of  apparent  pores  has  been 
most  animated  in  the  case  of  the  genera  Navicula  and  Pinnularia,  which 
present  a  large  rounded  spot  at  each  extremity  of  the  frustule  and  a  central 
space  known  as  the  umbilicus*^;  with  a  tubular  or  canal-like  band  connecting 
them  together  (XII.  15,  21,  46 ;  XYI.  1).  Prom  the  umbihcus,  Ehrenberg 
believed  a  single  locomotive  organ  to  proceed — an  undivided  sole-like  foot, 
similar  to  the  locomotive  organ  of  snails,  whilst  he  represented  the  terminal 
jDoints  to  be  orifices  for  the  purposes  of  nutrition  (IX.  134).  Although 
denjdng  the  offices  assigned  them  by  the  Berlin  micrographer,  Kiitzing  coin- 
cided with  him  in  the  belief  of  their  being  actual  pores,  and  supposed  that 
they  give  exit  to  a  gelatinous  substance,  such  as  is  actually  found  sur- 
rounding some  Navkulce,  and  becomes  a  prominent  character  in  the  tribe  of 
Diatomeae  represented  by  ScJiizonema.  Schleiden  (Princijyles  of  Botany,  hy 
Lanhester,  p.  594)  speaks  of  the  longitudinal  band  as  a  cleft,  and  of  the 
median  and  terminal  spots  as  circular  enlargements  or  thickened  spots  of 
silicious  matter.  He  moreover  appends  an  enlarged  lateral  view  of  a  Pin- 
nularia (XYI.  2,  3,  4,  5),  to  prove  that  the  seeming  central  orifice  is  simply 
a  depression.  This  explanation  of  their  nature  coincides  in  the  main  with 
that  given  by  Prof.  Smith,  who  asserts  that  these  markings  are  due  to  a  lon- 
gitudinal band  of  condensed  and  more  solid  silex,  widened  into  small  expan- 
sions at  the  centre  and  extremities,  or  at  the  extremities  only,  and  probably 
designed  to  give  firmness  to  the  valve.  "  That  these  expansions  (he  adds) 
are  not  perforations  in  the  valve,  as  alleged  by  Ehrenberg,  and  acquiesced  in 
by  Kiitzing,  might  be  shown  in  various  ways.  The  internal  contents  of  the 
frustule  never  escape  at  such  points  when  the  frustule  is  subjected  to  pressure, 
but  invariably  at  the  suture  or  the  extremities  ....  nor  does  the  valve  when 
fractured  show  any  disposition  to  break  at  the  expansions  of  the  central  Hne, 
as  would  necessarily  be  the  case  were  such  points  perforations,  and  not 
nodules.  Moreover,  the  central  band  of  silex  is  itself  frequently  traversed  by 
a  narrow  line  which  arises  from  the  confluence  of  a  series  of  cells,  which 
thus  form  a  minute  tube  ;  but  this  tube  invariably  ends  in  a  rounded  extre- 
mity at  the  central  and  terminal  nodules,  and  does  not  pass  into  an  opening 

or  aperture  in  the  valve The  bending  down  of  this  tube  and  the 

thickening  downwards  of  the  silex  at  the  nodules  give  the  semblance  of 
depressions  to  the  siu-face  of  the  valve  at  such  places.  But  I  am  disposed  to 
think  that  this  is  merely  an  optical  appearance,  and  at  aU  events  assured 
that  no  perforation  exists  at  such  points,  and  that  the  terms  apphed  to  these 
nodules  by  difi'erent  authors,  implying  that  they  are  openings  or  ostiola,  are 
altogether  inadmissible." 

Examples  of  nodules  at  the  centre  and  extremities  are  found  in  the 
^GneTQ.  Ampliiprora,  Pinnularia,  Navicula  (XII.  5,  6),  and  Gomphonema  (XII. 
15,  21,  46).  In  Stauroneis  the  central  nodule  is  developed  transversely,  so 
as  to  form  a  smooth  transverse  band  or  ^'stauros"  free  from  markings 
(XII.  7,  8,  18).     A  median  longitudinal  ridge  or  band  exists  in  Navicula, 


42  GENEBAL  HISTORY  OF  THE  INFUSOEIA. 

Stauroneisy  &c.,  whilst  in  Am])M]pleura  (XIII.  1,  2)  two  ridges  are  noticeable, 
but  whether  these  are  of  the  same  nature  structurally  is  uncertain.  In 
Doryphora,  again,  there  is  a  median  band,  but  no  nodules  distinguishable ;  and 
in  Eunotia  and  Himantidium  the  terminal  nodules  would  seem  exceptional  in 
character,  being  due,  as  Prof.  Smith  supposes,  *'  to  an  inflection  of  the  valves 
at  the  point  of  junction."  The  roimded  space  in  the  centre  of  the  discoid 
valves  of  Actinocyclus  (XI.  132)  and  Arachnoidiscus  (XV.  18-21J,  which  is 
devoid  of  areola,  is  designated  by  him  a  pseudo-nodule,  in  order,  we  presume, 
to  contrast  a  mere  bare  space  with  the  like  smooth  but  condensed  and  thick- 
ened spots  described  as  nodules. 

In  this  record  of  opinions,  those  of  Siebold  and  Niigeli  (J.  M.  S.  i.  196) 
should  not  be  omitted : — "  Precisely  at  the  spots  (says  the  former  writer)  at 
which  Ehrenberg  and  others  suppose  they  have  seen  six  openings  (i.  e.  three 
on  each  valve)  in  Navicula,  the  silicious  cell-membrane  is  thickened,  and  con- 
sequently forms  so  many  rounded  eminences  which  project  internally."  These 
views  thus  far  tally  with  those  of  Prof.  Smith  and  others ;  however,  a  few 
lines  further  on  in  his  essay,  Siebold  expresses  the  belief  that  the  lines 
running  along  the  middle  of  the  sui-faces  from  one  thickening  to  another 
"  are  to  be  referred  to  a  suture,  fissure,  or  rather  gap,  in  which  no  silicious 
matter  is  deposited,  so  that  in  these  places  the  delicate  primordial  membrane 
which  lines  the  silicious  shield  can  be  brought  into  close  relation  ^ith  the 
external  world.  I  come  to  this  conclusion  fi'om  the  circumstance  that  it  is 
exactly  at  these  four  sutures  or  fissures  that  the  water  surrounding  the 
Navicula  is  set  in  motion."     (See  p.  50.) 

Upon  the  whole  question  of  the  actual  nature  of  the  markings  on  the 
surface  of  the  silicious  fnistules,  we  are  happy  to  add  a  paper  published  by 
Prof.  Bailey  (SiU.  Journ.  ii.  349),  which  appears  to  afford  a  satisfactory 
elucidation.  We  present  it  entire,  with  the  practical  notes  on  manipulation, 
so  that  our  readers  may  imdertake  a  critical  examination  for  themselves  : — 

"  I  now  offer  proof  which  removes  all  doubt,  and  shows  that  these  markings 
are  neither  apertures  nor  depressions,  but  are  in  reahty  the  thickest  parts  of 
the  shell.  If  the  shells  are  placed  in  dilute  hydrofluoric  acid  and  watched 
by  the  aid  of  the  microscope  as  they  gradually  dissolve,  the  thinnest  parts  of 
course  dissolve  fii'st,  and  apertures,  if  any  exist,  should  become  enlarged. 
Now  the  very  parts  which  have  been  called  orifices  by  some,  and  depressions 
by  others,  are  the  last  of  all  to  disappear  as  the  shell  is  dissolved.  This  mode 
of  observation,  besides  establishing  the  fact  that  these  are  the  thickest  parts 
of  the  shell,  reveal  many  interesting  particulars  of  structure.  Thus,  in 
the  large  Pinnidarla,  it  may  be  seen,  with  even  a  low  power,  that  the  two 
parallel  bands  (separated  by  a  canal)  which  reach  fi'om  the  central  knob  to 
the  terminal  ones,  and  which  appear  smooth  before  the  application  of  acid, 
become  distinctly  striated  after  their  surface  is  dissolved  off,  as  does  also  the 
central  spot  itself,  showing  that  striae  which  existed  in  the  young  shell  are 
covered  up  and  nearly  obhterated^by  subsequent  deposits.  In  Staurosira  the 
cross-band  and  the  two  longitudinal  bands  are  the  last  to  dissolve,  and  these 
last  bands,  as  in  most  Diatomacea,  appear  separated  by  what  is  either  a  canal 
or  thin  portions  of  the  shell.  In  Grammatoj>hom  the  undulating  lines  are 
internal  plates,  which  are  the  last  to  dissolve.  In  HeliopeUa,  Actinoiytyclms, 
&c.,  the  polygonal  central  spot  is  the  last  to  disappear.  In  Isthmia,  the  spots 
on  the  surface,  which  at  first  appear  like  granular  projections,  are  in  reality 
thin  portions  of  the  shell,  and  imder  the  action  of  the  acid  they  soon  become 
holes.  The  acid  also  proves  that  the  larger  spots  at  the  transverse  bands  are 
a  series  of  large  arcuate  holes  in  the  silicious  shell,  and  the  piers  of  this 
series  of  arches  remain  some  time  after  the  rest  of  the  shell  has  vanished. 


OF  THE  DIATOME^.  43 

A  few  directions  on  the  mode  of  manipulation  may  be  useful.  As  the  fumes 
of  the  hydrofluoric  acid,  if  they  reach  the  lenses,  would  greatly  injure  them, 
it  is  advisable  to  protect  the  front  face  of  the  objectives  by  temporarily  con- 
necting to  them  a  thin  plate  of  mica  by  Canada  balsam,  as  mica  resists  the 
action  of  hydrofluoric  acid  much  better  than  glass.  I  prepare  the  cell  in 
which  the  solution  is  to  take  place  by  cementing  a  plate  of  mica  to  a  glass 
slide,  and  then  cover  all  its  surface,  except  a  central  small  disc,  with  wax. 
On  this  disc,  which  forms  a  cell,  the  shells  are  put  with  a  dish  of  water,  and 
after  adding  a  drop  or  two  of  acid  by  means  of  a  dropping-rod  of  silver  or 
platinum,  the  cell  is  covered  with  another  plate  of  mica,  and  the  slide  is  then 
placed  imder  the  microscope." 

Some  markings  of  the  surface,  apparent  only  as  striae  under  inferior  magni- 
fying powers,  are  in  several  genera  resolvable,  as  before  noticed  (p.  40),  into 
rows  of  rounded  dots,  e.  g.  in  Pleurosigma ;  and  in  consequence  such  specimens 
have  been  employed  to  try  the  relative  powers  of  microscopes,  and  are  spoken 
of  as  '  test  objects.'  But  the  powers  of  microscopes  have  been  more  severely 
tested  of  late  years,  by  the  endeavour  to  ascertain  whether  such  dots  are  eleva- 
tions or  de]3ressions  of  the  surface,  and,  as  might  be  expected,  the  dissension 
on  this  matter  has  equalled  that  respecting  the  central  band  and  umbilicus. 

Dr.  J.  W.  Griffith  is  in  favour  of  their  being  depressions  {Proc.  Roy.  Soc. 
1855).  He  argues  that,  as  the  markings  '^  are  evidently  depressions  in  the 
genera  and  species  with  coarsely  marked  valves  (IstJimia,  &c.),  we  should 
expect  from  analogy  that  the  same  would  apply  to  those  with  finer  markings 
(those  viz.  in  dispute,  Gyrosigma,  Pleurosigma,  and  others).  And  this  view 
receives  further  support  from  the  fact  that  under  varied  methods  of  illumina- 
tion corresponding  appearances  are  presented  by  the  markings  when  viewed 
by  the  microscope — from  those  which  are  very  large,  as  in  Isthmia,  through 
those  of  moderate  and  small  size,  as  in  the  species  of  Coscinodiscus,  down  to 
those  in  which  they  are  extremely  minute,  for  instance  in  Gyrosigma, 
&c.  The  angular  (triangular  or  quadrangular)  appearance  assumed  by  the 
markings  arises  from  the  light  transmitted  through  the  valves  being  un- 
equally oblique ;  this  may  be  readily  shoAvn  in  the  more  coarsely  marked 
valves  {IstJimia,  Coscinodiscus),  which  present  the  true  structural  appearance 
when  the  light  is  reflected  by  the  mirror  in  its  ordinary  position,  and  the 
spiuious  angular  appearance  when  the  light  is  rendered  oblique  by  moving 
the  mirror  to  one  side."  Another  statement  is  put  forward  by  the  same 
author  in  the  MicrograpMc  Dictionary  (Introduction,  p.  xxxiii)  in  support 
of  his  oj)inion,  viz.  "  that  the  line  of  fracture  of  the  broken  valves  passes 
through  the  rows  of  dots  on  the  dark  lines  corresponding  to  them,  showing 
that  they  are  thinner  and  weaker  than  the  rest  of  the  substance.  Had  these  dots 
represented  elevations,  the  valves  would  have  been  stronger  at  these  points." 

The  more  prevalent  opinion,  however,  is,  that  these  delicate  dots  in  rows 
are  elevations  of  the  sm-face.  Mr.  G.  Himt  {J.  M.  S.  1855,  pp.  174-175) 
adduces  an  observation  to  demonstrate  this  fact.  He  found  that  on  a  speci- 
men of  Pleurosigma  being  moistened,  the  markings  were  almost  entirely 
•obscured,  but  that  on  the  application  of  a  gentle  heat  "  the  moisture  slowly 
retreated,  lea\ing  patches  of  the  shell  diy,  and  with  the  markings  as  dis- 
tinct as  before."  On  observiaig  these  dry  parts  of  the  sheU,  they  were  seen  to 
be  uniformly  bounded  by  straight  ]hiQB, parallel  to  the  two  directions  of  least 
distance  of  the  dots.  "  Now  (continues  Mr.  Hunt),  on  the  supposition  of 
these  Httle  dots  being  elevations,  the  phenomenon  appears  to  me  easily  ex- 
plicable on  the  princijjle  of  capillaiy  attraction.  We  can  readily  conceive 
the  moisture  clinging  from  one  dot  to  another ;  and  it  would  always  have  a 
tendency  to  arrange  itself  in  lines  parallel  to  the  directions  of  least  distance. 


44  GENERAL  HISTORY  OF  THE  II^FUSOEIA. 

I  am,  however,  quite  at  a  loss  to  imagine  how  the  same  principle  would  apply 
on  the  hypothesis  that  the  dots  are  depressions,  nor  do  I  see  upon  what 
principle  the  phenomenon  is  explicable." 

A  (hrect  demonstration  that  the  markings  in  general  of  the  Diatomea3  are 
elevations  is  attempted  by  Mr.  Wenham,  whose  knowledge  of  optics  and  prac- 
tical skill  in  mechanical  manipulation  are  not  exceeded  by  any  microscopist 
of  the  present  day  {J.  M.  S.  1855,  j)p.  244^245).  To  quote  his  words— "A 
careful  study  of  the  coarser  varieties  will  distinctly  prove  that  the  markings 
are  raised  ribs  or  prominences  on  the  surfaces,  in  some  instances  on  one  side 
of  the  shell  only,  as  seen  in  the  Cajnpylodiscus  spiralis  and  others.  Though 
the  microscope  proves  this  fact  satisfactorily  in  the  large  species,  it  fails  to  do  so 
in  the  most  difficult  specimens,  chiefly  on  account  of  the  above-named  deceptive 
appearances,  arising  from  the  irregular  refraction  and  reflection  of  light.  It 
occurred  to  me  that  it  might  be  possible  to  obtain  a  perfect  cast  or  impression 
of  the  structure ;  and  by  viewing  this  as  an  opake  object,  the  error,  if  arising 
from  refraction,  would  be  avoided,  and  a  discovery  might  be  the  reward  of  the 
experiment.  I  have  succeeded  in  effecting  this  by  means  of  the  electrotype 
process,  which  for  many  reasons  is  to  be  preferred,  as  it  does  not  distort  the 
object,  and  is  so  minutely  faithful  that  even  the  mere  trace  of  organic  matter, 
left  by  a  slight  finger-mark,  is  perfectly  copied.  The  method  I  have  adopted 
is  this : — Procure  a  small  plate  of  metal  highly  polished  (a  piece  of  daguerreo- 
type plate  answers  extremely  well),  and,  after  gently  heating  it,  rub  a  piece 
of  bees- wax  over  the  surface ;  while  this  is  still  melted  wipe  it  nearlj^  all  off 
again  with  a  piece  of  rag,  so  as  to  allow  a  very  thin  film  to  remain ;  when 
the  plate  is  cold,  arrange  the  Diatomacea  or  other  objects,  previously  moist- 
ened, upon  the  waxed  surface,  heat  the  plate  again  to  at  least  212°,  in  order 
to  cement  the  objects  on  it.  The  wax  serves  a  twofold  purpose :  first,  its 
interposition  prevents  the  possibility  of  a  chemical  union  of  the  metallic 
deposit  with  the  plate ;  and  secondly,  the  object  is  secm^ely  held  thereto  by 
its  agency.  The  objects  are  now  ready  to  receive  a  coating  of  copper.  If 
the  battery  is  in  good  working  order,  three  or  four  hours  will  give  a  film 
sufficiently  strong  to  bear  removal ;  when  this  is  stripped  off,  if  the  process 
has  been  properly  managed,  the  objects  will  be  seen  imbedded  in  its  siu-face  ; 
whether  they  are  silicious  or  organic,  they  may  be  entirely  dissolved  out  by 
boiling  the  cast  in  a  test  tube  Avith  a  strong  solution  of  caustic  potash,  and 
afterwards  washing  with  distilled  water ;  the  copper  film  may  then  be  mounted 
in  Canada  balsam.  By  these  means  I  have  obtained  distinct  impressions  of 
the  markings  of  some  of  the  more  difficult  Diatomacea,  such  as  N.  (Pleuro- 
sigma)  Balticum,  P.  Hipjpocam'pus,  &c.,  leaving  no  doubt  of  their  prominent 
nature."     (See  MicroscojJic  Cabinet,  ed.  1832,  chap.  xvi.  and  xviii.) 

Besides  the  superficial  markings  explicable  on  the  supposition  of  an  invest- 
ing areolar  membrane,  and  the  sculptiu^ing  of  the  silicious  epiderm,  there 
are  others,  dependent  on  structural  modifications  of  the  sihcious  laminae  of 
the  valves,  and  on  inflections  of  these  internally.  Among  the  former  are 
many  of  the  stronger-marked  costae  and  pinnules  of  Ehrenberg ;  and  among 
the  latter  are  to  be  reckoned  the  imperfect  partitions  (^ septa')  seen  in 
several  genera,  and  those  peculiar  processes  of  the  internal  surface  which 
Kutzing  called  '  vittce.'  Schleiden  described  '  pinnules '  to  be  clefts  or  fissures. 
"  In  these  spots  (says  he),  the  shield  consists  of  two  leaves  lying  one  over  the 
other;  these  leaves  are  penetrated  by  the  small  clefts,  which,  when  both 
the  lamellae  touch  each  other,  are  somewhat  broader,  which  explains  the 
varying  breadth  of  the  clefts  according  to  the  alteration  of  the  foci.  Frag- 
ments in  which  this  structui'e  is  clearly  represented  may  be  frequently  obtained 
by  crushing  the  shield."  (XVI.  5,  6.) 


OF  THE  DIATOME^.  45 

Prof.  Smith  likewise  describes  inter-lamellar  channels,  under  the  name  of 
*  canalicidi/  "  hollowed  out  between  the  silicious  epiderm  and  internal  cell- 
membrane,  and  apparently  formed  by  waved  flexures  of  the  epidermal  enve- 
lope   They  are  very  conspicuous  in  Epithemia  longicornis,  and  form 

distinctive  characters  in  the  genera  Surirella  and  Campylodiscus.''^  This 
observer  also  regards  them  "  as  minute  canals  which  convey  the  nutri- 
mental  fluid  to  the  surface  of  the  internal  membrane,"  this  fluid  entering 
them  from  without  through  pores  or  fissures  existing  along  the  line  of  sutiu-e 
of  the  valves  (p.  50).  That  these  canals  are  not  modifications  of  the  cellular 
structure  of  the  silicious  epiderm  is  shown  by  the  cii'cumstance  of  the  stri86 
passing  uninteiTuptedly  over  the  entire  surface  of  the  valves  in  some  Epithemice. 

The  costae  of  Campylodiscus  equally  appear  to  be  canaliculi,  and  are  dis- 
posed in  a  radiate  manner.  In  Surirella  and  TryhJionella  these  canals  are 
usually  parallel,  whilst  in  Mastogloia  they  take  the  form  of  loculi. 

Kiitzing  assigned  a  special  structure  and  purpose  to  the  markings  he 
called  '  vittce,'  and  used  them  in  forming  a  subsection  of  Diatomeae  he  called 
Vittatce.  The  Kev.  Prof.  Smith  remarks  that  to  him  these  markings  do  not 
seem  special  organs,  but  modifications  in  the  outline  of  the  valve,  which  is 
inflected.  In  Grammatoplwra  (XI.  48,  49,  52,  53)  these  inflections  con- 
stitute a  leading  feature  of  the  genus,  and,  from  their  resemblance  to  written 
characters,  have  suggested  its  name.  In  this  instance  they  form  incomplete 
septa. 

The  terms  striae  and  costae  or  pinnules  are  not  synonymous.  Striae  are 
the  finer  lines  of  slight  breadth,  which  may  look  like  narrow  grooves  or 
ridges,  whilst  costae  or  pinnules  are  the  wider  markings,  having  an  evident 
double  contoiu',  and  the  appearance  of  fissui^es  or  canals.  The  fineness  of 
some  striae  is  such  that,  as  before  noted,  they  may  be  readily  overlooked ; 
however,  their  presence,  when  not  positively  demonstrable,  may  be  assumed 
by  the  coloui's  displayed  on  focusing  diied  specimens.  An  analogous  fact 
presents  itself  in  the  case  of  mother-of-pearl,  which  owes  its  varying  and 
beautiful  colours  to  the  existence  of  fine  lines  covering  its  surface.  The 
colour  varies  in  different  species,  and  is  due  to  the  refraction  of  the  rays  of 
light  passing  through  the  silicious  epiderm  ;  its  shades  depend  on  the  direction 
of  the  striae  and  on  their  distance  from  each  other ;  its  aid  may  therefore  be 
advantageously  evoked  in  the  determination  of  species. 

Striae  generally  seem  to  be  produced  by  the  confluence  of  minute  rounded 
points  or  beads — in  other  words,  are  commonly  moniliform,  and  often  extend, 
as  products  of  an  investing  areolar  tissue,  over  the  entire  surface  of  the  valves, 
unlike  those  costae  which  originate  in  structural  peculiarities  of  the  silicious 
plates.  Rows  of  puncta  occur  in  Nitzschia,  and  moniliform  striae  in  Navicida, 
Pleiirosigma,  Gomphonema,  and  Podosplienia.  To  the  confluence  of  the 
superficial  cells,  Mr.  Smith  attributes  the  production  of  the  costae  of  Pinnu- 
laiia,  whilst  those  of  Achnanthes  he  looks  upon  as  thickenings  on  the  under 
surface  of  the  silicious  valves,  and  generally  similar  to  those  of  Istlimia,  which 
line  the  valves  and  anastomose  on  their  under  sui^face ;  lastly,  the  striae  of 
Rhahdonema  are  constituted  of  series  of  oblong  cells. 

The  value  of  the  external  markings  of  Diatomeae,  in  a  systematic  point  of 
view,  has  been  much  discussed.  Ehrenberg  assumed  the  number  of  striae 
or  of  costae  or  pinnules  to  be  constant  in  the  same  space  in  each  species,  and 
accordingly  gives  the  number  of  striae  counted  within  a  given  fraction  of  a 
line.  A  great  multitude  of  species  was  the  consequence  of  this  plan ;  never- 
theless the  mere  fact  of  number  of  striae  within  a  given  space  cannot  be  esteemed 
a  valid  specific  character  by  itself ;  for  it  seems  quite  clear  that  the  relative 
closeness  of  striae,  their  number  within  the  -001  of  an  inch,  varies  according 


46  GEKEEAL  HISTOEY  OF  THE  INFUSORIA. 

to  the  age  and  to  the  size  of  the  valves,  and  both  size  and  figure  are  consi- 
derably aifected  by  circumstances  of  growth,  of  locality,  and  the  like.  A 
writer  in  the  Microscoj^ical  Journal  (1855,  p.  307)  suggests  that  the  number 
of  striae  on  the  entire  valve  may  supply  a  more  stable  character ;  yet  even 
on  this  point  we  are  wanting  in  direct  observ'ation  to  show  that  this  number 
may  not  be  affected  by  accidental  circumstances. 

Although  "  the  relative  distance  of  the  strise  and  their  greater  or  less  dis- 
tinctness "  be  accounted  by  Prof.  Smith  of  specific  importance,  yet  he  is 
obliged  to  admit  (J.  M.  S.  1853,  p.  133)  that  it  is  by  no  means  certain  that 
these  features  may  not  to  a  slight  extent  be  modified  by  localities  and  age, 
and  is  disposed  to  believe  that  they  are  certain  guides  only  when  we  have 
made  allowance  for  these  conditions,  and  that  while  they  are  constant  in 
fnistules  originally  from  the  same  embryo,  they  may  slightly  vary  in  those 
which  owe  their  birth  to  difierent  embryonic  cells.  It  is  also  worthy  of 
note  that,  in  certain  instances,  e.  g.  in  Odontidium  hyemalis,  Ejnthemia  A^xus, 
&c.,  the  costse  are  frequently  more  numerous  on  one  valve  than  on  the  other. 

Other  illustrations  of  the  variation  in  the  number  and  in  the  distinctness 
of  striae  in  the  same  species  are  to  be  found  in  the  late  lamented  Dr.  Gregory's 
valuable  papers  (T.  M.  S.  1855,  p.  10).  The  relative  position  of  striae — if 
parallel  or  radiate,  their  monihform  or  confluent  character,  their  equal  and 
general  diffusion  over  the  entire  surface,  or  theii'  absence  at  parts,  are  other 
circumstances  available  for  the  pmposes  of  classification. 

Besides  striation,  the  other  descriptions  of  superficial  markings  are  resorted 
to  for  specific  and  generic  characters.  Such  are  the  presence  or  absence  of 
a  median  band,  with  central  and  terminal  nodules,  the  existence  of  a  trans- 
verse band,  the  figure,  relative  position  and  aggregation  of  the  areolae  or  cells 
of  the  surface.  The  median  and  transverse  bands  have  been  employed  by 
aU  systematists,  and  would  seem  well  suited  to  furnish  characteristics  by  their 
constancy.  The  same  may  be  said  of  the  pore-like  spots  or  nodules.  Kiitzing 
went  so  far  as  to  make  the  presence  or  absence  of  a  central  nodule  or  um- 
bihcus  the  turning-point  in  his  grand  division  of  the  Diatomeae  into  um- 
bilicated  and  non-umbilicated. 

Lastly,  speaking  generally,  the  precaution  intimated  by  Prof.  Walker- Arnott 
(p. 39),  of  having  specimens,  intended  to  be  compared  together  for  the  determi- 
nation of  specific  forms,  similaiiy  prepared,  must  ever  be  borne  in  mind  where 
the  superficial  markings  are  referred  to  for  characters;  otherwise  an  excessive 
and  erroneous  multiplication  of  species,  and  a  deplorable  confusion  will  result. 

We  have  already  seen  that  the  connecting  membrane  is  not  an  essential 
segment  of  a  Diatomaceous  frustule,  but  an  after- development  in  connexion 
with  the  process  of  self- division;  yet,  notwdthstanding,  it  is  so  frequently 
present,  and  in  many  examples  its  dimensions  and  characters  are  so  marked, 
that  it  supplies  an  important  element  in  specific  and  generic  descriptions. 

In  the  circular  and  discoid  Diatomeae,  it  assumes  the  form  of  a  continuous 
ring  (XI.  40,  42),  but  in  many  oblong  and  navicular  frustules  it  is  itself 
oblong  or  navicular,  having  a  figure  the  reverse  of  the  valves  it  is  placed 
between  (XII.  17,  24,  31 ;  XIII.  5,  6,  7).  In  these  latter  and  in  other 
instances  it  is  frequently  separable  into  two  portions,  at  the  opposite  extre- 
mities of  the  frustules  where  the  silex  is  absent ;  and  hence  it  is  that  the 
shells  of  the  Diatomeae  have  been  described  by  Meneghini  and  other  writers 
as  composed  of  foiu'  segments. 

In  general,  the  proportion  of  silex  in  its  constitution  is  less  than  that  in 
the  valves;  and  the  existence  of  markings— of  areolae,  striae,  and  the  like— 
is  also  much  rarer.  Where  they  do  occiu-,  they  furnish  useful  particulars 
in  defining  species  and  genera.     The  small  development  of  the  connecting 


OF  THE  DIATOMEiE,  47 

membrane  in  Pleurosigmn  is  a  remarkable  feature  of  that  genus,  whilst  in 
Gomplionema  (XII.  28,  53),  and  other  genera  with  cuneate  (wedge-shaped) 
frustules,  the  figure  is  due  to  the  greater  development  of  this  segment  at  one 
end  than  at  the  other.  In  Amphiprora  (XIII.  5,  6),  Achnanilies,  Himanti- 
clium  (XII.  50,  52),  and  Melosira,  the  connecting  membrane  is  striated,  and 
in  Biddiilpliia  (II.  48),  Isthmia  (X.  183),  and  Amphitetras  (XI.  21,  22)  is 
cellulate  or  areolate. 

In  certain  genera  the  connecting  membrane  takes  on  an  extraordinary 
development,  which  greatly  modifies  the  figure  of  the  frustules.  Instead  of 
being  Hmited  to  the  interspace  between  the  opposed  valves,  it  extends  on 
either  side  beyond  the  sutures  (XII.  9),  presents  itself  as  a  band  of  greater 
or  less  width,  and  acquires  an  unusual  persistence.  Under  this  form  it  con- 
stitutes the  '  cingulum '  of  descriptive  wiiters,  and  is  seen  in  Ampliitetras, 
Biddulphia,  Podosira,  and  Melosira.  In  the  last  two  genera.  Prof.  Smith 
tells  us,  the  persistence  of  this  cii^cular  band  is  ''  eminently  conspicuous, 
retaining  the  frustules  after  self- division  in  a  geminate  union  until  the  self- 
dividing  process  is  renewed." 

Contents  of  Feustules. — Nucleus,  supposed  Digestive  Sacs,  Heproductive 
Vesicles,  ^r. — The  organic  membrane  of  the  frustules  of  Diatomeae,  strength- 
ened externally  by  the  silicious  plates,  encloses  within  its  cell-like  cavity  a 
soft  mucilaginous  substance  filled  with  numerous  granules  and  globules,  and 
usually  of  a  yeUow-brown  or  orange-brown  colour,  but  at  times  of  a 
green  hue,  and  technically  known  as  the  *  endoclirome,^  or  in  Klitzing's 
phi'aseology,  the  '  gonimic  substance.^  The  granular  matter  is  particu- 
larly aggregated  about  the  organic  waU,  leaving  the  central  portion  more 
clear.  In  this  clear  central  space  is  a  transparent  vesicle,  representing  the 
nucleus  of  the  cell,  having  the  granules  frequently  collected  around  it  in  an 
annular  form.  Nageli  states  that  the  nucleus,  enclosing  a  nucleolus,  lies 
sometimes  free  in  the  centre  of  the  frustular  cavity,  but  at  other  times  is 
affixed  at  one  spot  to  the  wall,  and  therefore  '  parietal.'  He  also  describes 
two  sorts  of  nuclei,  viz.  primary  and  secondary,  attributing  to  the  former  the 
active  part.  Schleiden  represents  the  nucleus  to  be  primarily  concerned  in 
the  original  formation  of  the  cell,  as  well  as  in  its  subsequent  multiplication 
by  seK- division. 

Among  other  elements  of  the  endochrome  are  more  or  fewer  rather 
translucent  globules,  which  Prof.  Smith  believes,  like  Kiitzing,  to  be  secre- 
tions of  the  cell,  of  a  fatty  or  oily  composition,  and  to  be  the  source  of  the 
peculiar  odoiu*  emitted  on  burning  the  Diatomeae.  In  support  of  this 
\'iew  Kiitzing  states  that  he  has  occasionally  seen  two  coalesce,  proving  the 
absence  of  proper  walls,  and  expresses  his  conviction  that  these  corpuscles 
are  akin  to  the  amylaceous  secretions  of  the  Desmidieae  and  Confeiwae  and  the 
starch-granules  of  the  higher  vegetables. 

These  globules  are  smaller  than  the  nuclear  space,  and  occupy  a  pretty 
constant  and  definite  position.  "  The  number  of  these  globules  is  frequently 
four,  often  placed  near  the  extremities,  or  more  rarely  clustered  round  the 
central  vesicle."  Meneghrni  (op.  cit.  R.  S.  p.  364),  alluding  to  these  vesicles, 
states  them  to  vary  in  number,  size,  and  disposition  at  different  stages,  and 
according  to  various  conditions,  even  under  the  eye  of  the  observer. 

These  apparent  oU-globules  were  called  by  Ehrenberg  male  sexual  glands 
or  testes,  whilst  those  other  vesicles  distributed  within  the  mucilaginous 
matter,  often  about  the  nucleus,  were  named  stomachs.  The  latter  idea  he 
based  especially  on  a  series  of  experiments  to  introduce  colouilng  matter 
into  the  interior  of  the  frustules,  in  which  he  believed  he  succeeded.  The 
species  mentioned  are  Navicid a  gracilis,  N.  Ampjhishoena,  N.  viridida,  N.fidva, 


48  GENERAL  HISTORY  OF  THE  INFUSORIA. 

N.  Nitzschii,  N.  lanceolata,  and  N.  capitata ;  also  Gomplionema  truncatum, 
Cocconema  cistula,  Arthrodesmus  quadricattclatus,  and  Clostei^imn  acerosum. 
The  two  last,  however,  are  Desmidieae.  In  the  seven  species  of  Navicula 
enumerated,  fi'om  4  to  20  little  stomach- sacs  are  said  to  have  become  filled 
with  the  indigo  employed  as  the  colouring  matter. 

*'  This  effect  (as  Meneghini  remarks)  could  only  be  produced  by  keeping  the 
Diatomeae  a  long  time  in  water  laden  ^vith  particles  of  indigo,  and  often  re- 
newed." Kiitzing  deduced  an  opposite  conclusion  from  these  experiments, 
viz.  that  they  were  solid  corpuscles  which,  being  seated  near  an  opening, 
exerted  an  especial  attraction  upon  the  colouring  matter.  Meyen  argued, 
so  long  since  as  1839  {Jahreshericht  d.  Akad.  Berlin),  against  the  supposed 
stomach-sacs  and  the  entrance  of  colouring  matter  within  them.  His 
objections  are  thus  expressed  : — "  On  the  one  hand,  I  can  see  no  stomach-sacs 
in  the  Naviculce,  and  never  observed  in  the  living  and  moving  Bacillaria  the 
colouring  matter  received  at  one  extremity  and  carried  towards  the  centre, 
where  these  stomach-sacs  should  lie,  whilst  among  the  ciliated  Infusoria 
such  observations  are  easy ;  on  the  other  hand,  it  is  not  uncommon,  especially 
in  the  larger  species,  to  see  the  molecules  of  the  colouring  matter  employed, 
lie  upon  the  middle  of  the  broad  ventral  surface,  looking  as  if  actually  within 
the  organism ;  but  if  a  glass  plate  be  placed  upon  the  specimen  and  then 
carefully  removed,  the  particles  of  colouring  matter  are  taken  away  with  it." 
Even  Ehrenberg  admitted  that  the  presumed  stomach-sacs  varied  in  number, 
were  quite  irregular  in  their  disposition  in  the  interior,  and  not  unfrequently 
wanting  altogether.  This  last  circumstance,  Kiitzing  remarks,  is  opposed  to 
the  belief  in  their  digestive  functions,  since  such  important  organs  as  stomachs 
can  never  be  supposed  absent. 

Although  the  existence  of  this  fanciful  polygastric  apparatus  in  the 
DiatomeaB  is  scarcely  worth  controverting,  yet  we  may  add  to  the  above 
objections  to  it  the  fact  that,  in  the  hands  of  other  experimenters,  the 
attempt  to  introduce  colouring  matter  by  any  definite  apertures  into  the 
frustules  of  this  family  has  been  unsuccessftd. 

The  arrangement  of  the  mucilaginous  endochrome,  or  rather  of  its  pro- 
minent globules,  vesicles,  and  granules,  is  sufficiently  definite  and  constant 
in  the  same  species  to  afford  useful  characteristics.  At  one  time  these 
molecules  are  diffused  rather  irregularly ;  at  another  they  are  collected  in  a 
rounded  heap  towards  the  centre,  whilst  at  another  they  are  disposed  in 
lines  radiating  from  the  nucleus,  or  formed  in  a  layer  upon  the  cell-waU, — 
**  at  all  times  "  (adds  Prof.  Smith)  "  having  one  or  several  oily  globules, 
which  occupy  in  different  species  different  positions,  but  are  constant  in 
number  and  position  in  the  same  species.  The  minute  granules  "  (he  con- 
tinues, i.  p.  20)  "  are  generally  accumulated  in  thin  layers  towards  the  internal 
cell-waUs :  when  the  frustule  is  so  turned  that  this  layer  of  endochrome  is 
presented  edgeways  to  the  eye,  the  granules  appear  to  be  chiefly  aggregated 
into  two  plates  applied  to  the  opposite  sides  of  the  frustule ;  and  when  self- 
division  is  in  progress  and  the  cell-contents  are  divided  into  two  portions, 
such  a  separation  or  temporary  aggregation  must  necessarily  ensue ;  but  in 
the  simplest  condition  of  the  fi^ustule  the  contents  are  diffused  over  the  entire 
surface  of  the  cell- walls,  precisely  as  may  be  seen  in  the  cells  of  many  of  the 
larger  Algae,  or  of  some  water-plants  of  a  higher  order,  as  in  the  leaves  of 
Hydrocharis  Morsus-rcmce  and  others." 

Schultze  has  recently  represented  (Milll.  ArcMv,  1858)  a  definite  peculiar 
disposition  of  the  endochrome — of  its  mucilaginous  and  granular  portions  and 
its'  coloured  corpuscles.  In  the  more  or  less  quadrate  frustules  of  Denticellay 
and  in  the  circular  ones  of  Coscinodiscus,  he  describes  the  existence  of  a  central 


OF  THE  DIATOME^.  49 

clear  vesicle,  from  which  thin,  finely  granular  lines  or  threads  extend  and 
intersect  and  branch  in  a  reticulate  manner,  with  a  more  or  less  distinct 
radiation,  the  more  fluid  contents  flowing  between  them.  In  the  long  cylin- 
drical fnistules  of  RMzosolenia,  on  the  contrary,  these  granular  mucilaginous 
threads  run  longitudinally.  Within  these  threads  the  colom^ing,  yellowish- 
brown  corpuscles,  not  circular,  but,  as  Schultze  says,  irregularly  multangular, 
are  disposed  and  retained  in  their  position.  Although  these  researches  extend 
to  so  few  forms,  yet  we  are  disposed  to  believe  that  this  disposition  of  the 
elements  of  the  endochrome  will  be  found  to  be  the  rule.  A  regular  arrange- 
ment is  figured  in  many  di'a wings  of  the  Diatomeae  by  various  observers ; 
and  where  it  does  not  appear  it  is  most  probably  due  to  the  want  of  attention 
to  its  presence, — or  to  the  excessive  multiplication  of  the  coloming  corpuscles, 
causing  them  to  appear  spread  beneath  the  envelopes  as  a  pretty  uniform 
layer.  A  definite  disposition  of  the  chlorophyll-granules  is  common  in  plants, 
particularly  among  the  lower  Algae,  and  owes  its  constancy  to  the  presence 
of  the  mucous  and  less  fluid  contents,  which  are  condensed  from  the  sur- 
roimding  fluid  in  the  form  of  filmy  threads,  and  serv^e  as  a  nidus  to  the  colour- 
ing particles.  In  this  disposition,  therefore,  of  the  endochrome  and  its  cor- 
puscles we  perceive  a  vegetable  character,  as  contrasted  with  what  is  seen  in 
animal  ceUs,  and  find  in  it  an  additional  argument  for  the  vegetable  nature 
of  the  Diatomeae. 

Notwithstanding  that  the  endochrome  is,  by  pretty  general  consent,  ho- 
mologous with  that  of  recognized  vegetable  Algae,  still  it  would  seem  to  be 
of  a  different  chemical  composition  as  well  as  of  another  coloui\  Kiitzing, 
indeed,  insisted  on  the  fact  of  the  similarity  of  the  endochrome  to  the 
gonimic  substance  of  Algae,  from  the  circumstance  that,  by  means  of  alcohol, 
he  was  able  to  extract  a  coloimng  matter  similar  to  chlorophyll ;  yet  Eaben- 
horst  and  others  have  remarked  a  difference  in  chemical  nature.  Prof.  Smith 
again,  whilst  admitting  the  imperfection  of  our  knowledge  on  this  point, 
goes  on  to  say  that  "  the  tincture  of  iodine  causes  the  internal  membrane  to 
contract  upon  the  cell-contents,  and  converts  these  from  the  golden  yellow 
which  they  exhibit  in  some  species,  into  bright  green,  and  that  a  weak 
solution  of  sulphuric  acid,  while  it  eff'ects  the  same  contraction  in  the  ceU- 
waU,  gives  to  the  contents,  which  have  been  previously  treated  with  iodine, 
a  dark-brown  hue :  alcohol,  on  the  other  hand,  as  in  the  case  of  vegetable 
ceUs  in  general,  dissolves  the  utricle  and  its  contained  endochrome,  or  at  all 
events  entirely  removes  their  colour,  and  leaves  their  silicious  epiderm  in  a 
state  of  perfect  transparency.  It  does  not,  however,  dissolve  the  envelope  in 
which  the  frustules  of  the  frondose  forms  are  imbedded,  nor  the  filamentous 
stipes  or  gelatinous  ciLshions  to  which  other  species  are  attached." 

Meneghini  {op.  cit.  R.  S.  p.  365)  contends  that  the  identity  in  nature  of 
the  endochrome  of  Diatomeae  and  of  Algae  is  not  proved.  "  Its  colour  is  dif- 
ferent ;  and  it  is  diiferently  coloured  by  chemical  reagents.  The  resemblance 
to  it  in  some  instances,  as  in  Melosira,  in  regard  to  conformation  and  suc- 
cessive alterations,  is  only  in  appearance.  In  the  endochrome  of  Algae  the 
monogonimic  substance  begins  by  presenting  a  granular  appearance  ;  then  it 
becomes  distinctly  granulated  and  changes  into  the  polygonimic  substance, 
so  minutely  described  by  Kiitzing.  But  these  changes  do  not  occur  in 
the  coloured  substance  of  Diatomeae.  If  we  insist  on  a  parallel,  we  can 
only  compare  it  to  the  cryptogonimic  substance  of  Byssoidia,  CaUithcimnia, 
Griffiihsia,  and  Polysi])ho7iia.  It  divides  into  two  parts  which  successively 
undergo  ulterior  division ;  and  in  regard  to  these  changes  we  may  observe 
that  there  is  an  essential  distinction  between  those  that  occur  during  life  and 
those  that  take  place  after  death,  the  greater  number  happening  in  the  latter 


50  GENERAL  HISTOEY  OF  THE  INFrSORTA. 

condition The  identity  of  this  substance  with  endoclirome  is  contradicted 

by  KUtzing's  own  experiments,  ......  which  prove  it  to  be  very  rich  in 

nitrogen :  it  emits  ammonia  copiously  when  decomposed  by  heat ;  and  this 
can  only  proceed  from  a  substance  abounding  with  it,  which  such  a  decom- 
position compels  it  to  yield  up.  Nor,  on  the  contrary,  do  I  beheve  that  there 
is  any  weight  in  the  argument  from  the  solubility  of  its  colouring  principle 
in  alcohol ;  for  this  is  not  aproperty  pecuhar  to  chlorophyll,  or  to  any  sub- 
stance of  vegetable  origin." 

The  contents  of  the  frustules  are  brought  into  relation  with  the  surround- 
ing medium  through  certain  pores  or  fissures,  which  have  been  referred  to  as 
existing  here  and  there  along  the  sutures  between  the  opposed  valves,  or 
othermse  between  the  valves  and  the  interposed  connecting  membrane.  The 
existence  of  such  openings  in  the  siHcious  envelope,  and  the  consequent 
exposure  of  the  organic  internal  or  primordial  membrane  in  the  situations 
mentioned,  have  been  demonstrated  chiefly  by  the  researches  of  Prof.  Smith, 
who  apphes  to  them  the  name  of  'foramina.^  Thej^  are  thus  described  {op. 
cit.  i.  p.  15)  : — "  Along  the  line  of  suture  in  discifonn  or  circular  fnistules, 
but  more  generally  at  the  extremities  of  the  valves  only,  when  the  Diatom  is 
of  an  oblong,  hnear,  or  elongated  form,  there  exist  perforations  in  the  silex 
which  permit  the  surrounding  water  to  have  access  to  the  sm-face  of  the 
internal  cell-membrane.  The  fonnation  of  silex  seems  occasionally  to  be 
arrested  in  the  neighboui-hood  of  these  spots  ;  and  the  connecting  membrane 
is  in  consequence  either  wholly  or  partially  interrupted  at  such  places.  Thus, 
after  the  internal  cell-membrane  has  been  removed  by  acid,  when  it  often 
happens  that  the  valves  fall  away  from  the  connecting  membrane,  the  latter 
separates  into  two  parts ;  and  the  fi'ustule  has  in  consequence  been  described 
as  consisting  of  foui'  plates.  The  interruptions  in  the  silicious  epiderm  are 
usually  apparent  as  shght  depressions  at  the  extremities  of  the  frustule ;  and 
the  appearances  they  present  have  been  denominated  '  puncta'  by  Mr.  Ralfs. 
In  some  species  these  interruptions  are  more  numerous,  being  found  along 
the  entire  line  of  suture,  and  are  often  connected  with  minute  canals  hollowed 
out  between  the  silicious  epidenn  and  the  internal  ceU-membrane,  and  ap- 
parently formed  by  waved  flexui'es  of  the  epidermal  envelope."  The  latter 
constitute  the  canalicuh  heretofore  spoken  of  (p.  45). 

Siebold  regarded  the  longitudinal  bands  having  a  double  outhne,  and  ex- 
tending from  the  apparent  dots  or  pores  at  either  end  of  Naviculce  to  near  the 
centre,  to  be  fissures ;  but  the  account  previously  given  proves  this  able  man 
to  have  been  mistaken  on  this  point.  Like  Prof.  Smith,  however,  he  con- 
cluded that  the  internal  membrane  was  imperforate,  and  that  it  served  as 
the  medium  for  the  exosmosis  and  endosmosis  attending  the  function  of 
nutrition. 

Movements  of  the  Diatomeje  ; — their  character  and  causes  ; — Cilia  ; — 
Circulation  of  Contents  ; — Respiration. — The  peculiar  movements  noticed 
in  many  Diatomeae  have  attracted  the  observation  of  all  microscopists,  and 
have  induced  many,  especially  among  the  older  observers,  to  receive  it  as 
evidence  of  their  animal  nature  ;  but  even  those  who  agree  on  this  point 
are  in  no  better  accord  among  themselves  respecting  its  cause  than  are  those 
who  refer  these  beings  to  the  vegetable  kingdom. 

The  power  of  movement  is  not  confined  to  those  only  which  are  free,  but 
also  to  concatenate  and  to  some  fixed  forms,  e.  g.  Synedra,  which  move  on  their 
fixed  extremity.  There  is  considerable  diversity  both  in  the  manner  and  extent 
of  movement  of  different  species;  but  in  none  is  it  exhibited  in  an  equal 
degree  to  that  seen  in  the  spores  of  Algae.  "  The  motion,"  says  Prof.  Smith, 
"  is  of  a  peculiar  kind,  being  generally  a  series  of  jerks  producing  a  rectilinear 


OF  THE  DIATOME^.  51 

moTement  in  one  direction,  and  a  return  upon  nearly  the  same  path,  after  a 
few  moments'  pause,  by  another  series  of  isochronal  impulsions.  The  move- 
ment is  evidently  of  a  mechanical  natui'e,  produced  by  the  operation  of  a  force 
not  depending  upon  the  volition  of  the  living  organisms :  an  obstacle  in  the 
path  is  not  avoided,  but  pushed  aside ;  or,  if  it  be  sufficient  to  avert  the 
onward  course  of  the  fi'ustule,  the  latter  is  detained  for  a  time  equal  to  that 
which  it  would  have  occupied  in  its  forward  progression,  and  then  retires 
from  the  impediment  as  if  it  had  accomplished  its  fuH  course.  There  is  cer- 
tainly no  character  of  animality  in  the  movement ;  and  the  observer,  familiar 
"vvith  the  phenomena  of  life  in  the  earlier  stages  of  vegetable  existence,  is 
constrained  to  see  a  coimterpart  in  the  involuntary  motions  of  the  filaments 
of  the  Oscillatorieae,  or  of  the  gemmiparous  spores  of  the  Fuci  and  Con- 
fervae." 

This  same  view  was  taken  by  Morren  in  1839  {op.  cit.),  who  says — ''  The 
movement  of  the  BaciUaria,  however  free  it  may  be,  is  by  no  means  so  free 
and  active  as  that  of  the  spores  of  Algae,  which  are  plants,  or,  at  least,  parts 
of  plants ;  and  the  motion  is  no  positive  ground  for  the  belief  in  their  ani- 
mality." 

The  cause  of  the  motion  of  the  Diatomese  has  hitherto  not  been  satisfacto- 
rily determined.  To  the  hypothesis  of  a  snail-like  expanding  foot  projecting 
fi'om  the  central  pore  or  umbilicus,  advanced  by  Ehrenberg,  we  have  already 
alluded  (p.  41);  and  since  no  one  original  observer,  in  spite  of  the  best-dii^ected 
efforts,  has  been  able  to  detect  the  remotest  evidence  of  such  an  organ,  and 
as  all  evidence  goes  to  show  that  no  actual  perforations  exist  at  the  point 
indicated  for  its  extrusion,  it  would  be  useless  to  raise  any  argument  upon  it. 
This  distinguished  natui^alist  subsequently  satisfied  himself  of  the  presence 
of  other  locomotive  organs  in  a  Navicida  (Surirelhi  gemma,  XII.  3,  4),  which 
he  has  thus  described : — "  Instead  of  a  snail-like  expanding  foot,  long  delicate 
threads  projected,  where  the  ribs  or  transverse  markings  of  the  sheU  joined 
the  ribless  lateral  portions,  and  which  the  creatui'e  voluntaiily  drew  in  or 
extended.  An  animalcule  ^th  of  a  line  long  had  24  for  every  two  plates, 
or  ninety- six  in  all ;  and  anteriorly,  at  its  broad  frontal  portion,  foui^  were 
visible.  Whether  these  organs  were  supernumerary,  and  existed  along  T\dth 
cirrhi,  &c.,  and  with  the  flat  snail-hke  foot  which  the  rest  of  the  Naviculce 
possess,  could  not  be  determined.  Longitudinal  clefts  at  the  broad  side  of  the 
shell  were  not  present ;  but  as  many  as  96  lateral  openings  for  the  exit  of  the 
ciiThi  were  perfectly  distinct."  These  ciliary  processes  were  farther  stated 
to  be  actively  vibratile,  and  to  be  retracted  or  extended  at  short  periods. 

Prof.  Smith  has  remarked  on  this  appearance,  that  the  presence  of  haii^s 
apparently  on  all  parts  of  the  frustule  may  often  be  detected,  and  that  he  has 
noticed  them  on  nearly  every  occasion  on  which  he  has  gathered  this  species, 
but  in  no  case  has  he  been  able  to  perceive  any  motion  in  such  hairs ;  and  he 
therefore  concludes  that  they  are  merely  a  parasitic  growth,  such  as  the 
mycelium  of  some  Algae.  He  has  also  seen  similar  appendages  to  other  Dia- 
tomeae,  but  in  every  case  devoid  of  motion. 

The  notion  of  exsertile  and  retractile  feet  has  been  renewed  by  M.  Focke 
{Comptes  Remlm,  1855,  p.  167),  who  attributes  the  movements  of  Navicida  to 
such  organs  of  a  temporary  kind,  which  he  says  pass  through  openiags  he 
has  detected  on  the  sides  of  the  lorica. 

Nageli  offered  the  following,  and,  to  Siebold's  mind,  satisfactory,  explana- 
tion of  the  forward  and  backward  movement,  as  well  of  many  Desmidie* 
as  of  Diatomeae  {J.  M.  S.  1853,  p.  195).  "  The  cells,"  he  writes,  "  have  no 
special  organs  for  these  movements.  But  as  in  consequence  of  their  nutri- 
tive processes  they  both  take  in  and  give  out  fluid  matters,  the  cells  neces- 

e2 


52  GENERAL  HISTORY  OF  THE  INFUSORIA. 

sarily  move  when  the  attraction  and  the  emission  of  the  fluids  is  unequally 
distributed  on  parts  of  the  surface,  and  is  so  active  as  to  overcome  the 
resistance  of  the  water.  This  motion,  consequently,  is  observed  more  particu- 
larly in  those  cells  which,  in  consequence  of  their  taper  form,  easily  pass 
through  the  water ;  these  cells,  moreover,  move  only  in  the  direction  of  theii' 
long  axis.  If  one  half  of  a  spindle-shaped  or  ellipsoidal  cell  chiefly  or  en- 
tirely admits  material,  the  other  half,  on  the  contrary,  giving  it  out,  the  cell 
moves  towards  the  side  where  the  admission  takes  place.  But  as  in  these 
cells  both  halves  are  physiologically  and  morphologically  exactly  alike,  so  it 
is  that  it  is  first  the  one  and  then  the  other  half  which  admits  or  emits,  and 
consequently  the  cell  moves  sometimes  in  one,  at  other  times  in  the  opposite 
direction." 

In  our  apprehension,  this  mechanical  interpretation  of  the  phenomenon  is 
not  sufficient ;  the  alternate  reception  and  discharge  of  fluid  matters  by  each 
opposite  half  requires  an  effort  of  imagination,  to  conceive,  unwarranted  by 
analogy.  We  shall,  however,  presently  see  that  Prof.  Smith  gives  the  pre- 
ference to  this  supposition,  amid  the  many  conflicting  fancies  of  authors  and 
the  obscurity  of  the  question. 

Encouraged  by  apparent  success  in  discovering  cilia  on  the  fronds  of  Des- 
midieae,  Mr.  Jabez  Hogg  searched  for  them  on  Diatomeae,  and  tells  us  {J.  M.  S. 

1855,  p.  235)  that  he  has  repeatedly  satisfied  himseK  that  their  motive  power 
is  derived  from  ciha  arranged  around  openings  at  either  end, — ^in  some  also 
around  the  central  openings,  which,  mth  those  ciha  at  the  ends,  act  as 
paddles  or  propellers.  He,  moreover,  states  his  impression  that  the  frustules 
have  a  degree  of  volition  sufficient  ''  to  move  along  and  to  steer  their  coiu'se  ; 
for  intervals  of  rest  and  motion  are  most  clearly  to  be  distinguished."  To 
this  behef  in  cilia  on  the  frustules  of  Diatoms,  Mr.  Wenham  is  as  determined 
an  opponent  as  he  is  to  the  Hke  hy[Dothesis  respecting  the  Desmidieae  (J.  M.  S. 

1856,  p.  159),  and  he  offers  the  folloTving  speculations  on  the  cause  of  the 
movements : — "  If  caused  by  the  action  of  ciha,  such  extremely  rapid  impulses 
would  be  required  to  propel  the  comparatively  large  body  through  the  water, 
that  surrounding  particles  would  be  jerked  away  far  and  Tvdde ;  a  similar 
effect  would  be  observed  if  the  propulsion  were  caused  by  the  reaction  of  a  jet 
of  water,  which,  according  to  knovni  laws  of  hydrodynamics,  must  neces- 
sarily be  ejected  with  a  rapidity  sufficient  to  indicate  the  existence  of  the 
current  a  long  distance  astern.  I  consider  that  there  is  no  ground  for 
assuming  the  motions  of  the  Diatomaceae  to  be  due  to  either  of  these  causes. 
They  are  ui'ged  forward  through  a  mass  of  sediment  without  displacing  any 
other  particles  than  those  they  immediately  come  in  contact  with,  and  quietly 
thnist  aside  heavy  obstacles  directly  in  their  way,  with  a  slow  but  decided 
mechanical  power,  apparently  only  to  be  obtained  from  an  abutment  against 
a  sohd  body.  In  studying  the  motions  of  the  Diatomeae,  I  have  frequently 
seen  one  get  into  a  position  such  as  to  become  either  supported  or  jammed 
endways  between  two  obstacles.  In  this  case,  particles  in  contact  with  the 
sides  are  carried  up  and  down  from  the  extreme  ends  with  a  jerking  move- 
ment and  a  strange  tendency  to  adherence,  the  Diatom  seeming  unwilling 
to  part  with  the  captured  particle.  Under  these  circumstances  I  have  dis- 
tinctly perceived  the  undulating  movement  of  an  exterior  membrane  ;  whether 
this  envelopes  the  whole  sui^face  of  the  silicious  valves  I  am  not  able  to 
determine,  nor  do  I  know  if  the  existence  of  such  a  membrane  has  yet  been 
recognized.  The  movement  that  I  refer  to  occupied  the  place  at  the  junction 
of  the  two  valves,  and  is  caused  by  the  imdulation  of  what  is  known  as  the 
*  connecting  membrane.'  This  will  account  for  the  progressive  motion  of 
the  Diatomeae,  which  is  performed  in  a   manner  analogous  to  that  of  the 


OF  THE  DIATOMEJE.  53 

Gasteropoda.  The  primaiy  cause,  however,  is  different,  and  not  due  to  any 
property  of  animal  vitality,  but  arises,  in  my  opinion,  merely  from  the  effects 
of  vegetable  circulation.  I  have  observed  several  corpuscles  of  uniform  size 
travel  to  and  fro  apparently  vrithin  the  membrane,  which  is  thus  raised  in 
weaves  by  their  passage."  Mr.  Wenham  foUows  up  this  explanation  by  a 
conjecture  with  respect  to  the  rarer  movements  of  the  Desmidieae.  "  As 
there  are  in  these,"  he  writes,  "  no  indications  of  either  external  orifices  or 
cilia,  may  not  their  locomotion  be  effected  by  the  currents  of  protoplasm 
forcing  their  way  between  the  primordial  utricle  and  outer  tunic,  which  will 
thus  be  raised  in  progressive  waves  if  the  investment  happens  to  be  in  a 
suitably  elastic  condition."  (See  p.  5.) 

The  undulating  movement  of  an  exterior  membrane  thus  indicated  by  Mr. 
Wenham,  over  the  surface  of  Diatomaceous  fnistules,  is  doubtless  identical 
-with  the  ciuTcnt  demonstrated  by  Siebold  by  means  of  indigo  (J.  M.  S. 
i.  pp.  196,  197).  The  latter  states  that  the  particles  of  this  colouring  matter 
which  come  in  contact  with  the  living  NavicuJce  are  set  into  a  quivering 
motion,  although  previously  quite  motionless ;  but  this  happens  only  along 
the  lines  of  the  foiu"  sutures,  the  particles  adherent  to  other  parts  of  the  shield 
remaining  motionless.  "  The  indigo  particles,  which  are  propelled  from  the 
terminal  towards  the  two  central  eminences,  are  never  observed  to  pass 
beyond  the  latter :  at  this  point  there  is  always  a  quiet  space,  fi'om  which 
the  particles  of  indigo  are  again  repelled  in  an  inverse  direction  towards  the 
extremities.  This  proves  that  the  linear  sutures,  as  may  in  fact  be  seen, 
do  not  extend  over  the  central  eminences  of  the  shield.  The  current  at  these 
clefts  is  occasionally  so  strong,  that  proportionally  large  bodies  are  set  in 
motion  by  it."  The  sutures  and  clefts  alluded  to  by  Siebold,  it  should  be 
imderstood,  are  not  the  sutures  between  the  valves  and  connecting  membrane, 
but  the  evident  lines  extending  between  the  apparent  pores  on  the  valves, 
and  w^hich,  to  his  apprehension,  are  actual  fissm^es  in  the  silicious  envelope, 
by  which  "  the  delicate  primordial  membrane  which  lines  the  sihcious  shield 
can  be  brought  into  close  relation  with  the  external  world."  This  belief  in 
the  presence  of  such  fissm^es  on  the  valves  we  have  previously  examined  and 
shown  to  be  unfounded.  (See  p.  41.) 

Prof.  Smith  has  the  following  remarks  on  this  debateable  point  of  the 
cause  of  the  motions  of  Diatomeae  {op.  cit.  vol.  i.  p.  xxiii) : — "  Of  the  cause 
of  these  movements,  I  fear  I  can  give  but  a  very  imperfect  account.  It 
appears  certain  that  they  do  not  arise  from  any  external  organs  of  motion. 
The  more  accui'ate  instruments  now  in  the  hands  of  the  observer  have  enabled 
him  confidently  to  affirm  that  all  statements  resting  upon  the  revelations  of 
more  imperfect  object-glasses,  which  have  assigned  motile  cilia,  or  feet,  to 
the  Diatomaceous  fi'ustule,  have  been  founded  upon  illusion  and  mistake. 
Among  the  hundreds  of  species  which  I  have  examined  in  every  stage  of 
growth  and  phase  of  movement,  aided  by  glasses  which  have  never  been 
surpassed  for  clearness  and  definition,  I  have  never  been  able  to  detect  any 
semblance  of  a  motile  organ ;  nor  have  I,  by  colouring  the  fluid  with 
carmine  or  indigo,  been  able  to  detect,  in  the  coloured  particles  surrounding 
the  Diatom,  those  rotatory  movements  which  indicate,  in  the  various  species 
of  true  infusorial  animalcules,  the  presence  of  cilia.  I  am  constrained  to 
believe  that  the  movements  of  the  Diatomaceae  are  owing  to  forces  operating 
within  the  frustule,  and  are  probably  connected  with  the  endosmotic  and 
exosmotic  action  of  the  cell.  The  fluids  which  are  concerned  in  these 
actions  must  enter  and  be  emitted  through  the  minute  foramina  at  the 
extremities  of  the  silicious  valves ;  and  it  may  easily  be  conceived  that  an 
exceedingly  small  quantity  of  water  expelled  through  these  minute  aper- 


54 


GENERAL  HISTOEY  OF  THE  INFrSOEIA. 


tures  would  be  sufficient  to  produce  moYements  in  bodies  of  so  little  specific 
gravity. 

"  If  the  motion  be  produced  by  the  exosmose  taking  place  alternately  at  one 
and  the  other  extremity,  while  endosmose  is  proceeding  at  the  other,  an 
alternating  movement  would  be  the  result  in  fnistules  of  a  linear  form, — 
while  in  others  of  an  elliptical  or  orbicular  outline,  in  which  foramina  exist 
along  the  entire  line  of  suture,  the  movements,  if  any,  must  be  irregular,  or 
slowly  lateral. 

"  Such  is  precisely  the  case.  The  backward  and  forward  movements  of 
the  Naviculece  have  been  already  described  ;  in  Sninrella  and  Campylodiscus 
the  motion  never  proceeds  farther  than  a  languid  roll  from  one  side  to  the 
other  ;  and  in  Gomphonema,  in  which  a  foramen,  fulfilling  the  nutritive  office, 
is  foimd  at  the  larger  extremity  only,  the  movement  is  a  hardly  perceptible 
advance  in  intermitted  jerks  in  the  dii-ection  of  the  narrow  end.  The  subject 
is,  however,  one  involved  in  much  obscurity,  and  is  probably  destined  to 
remain,  for  some  time  to  come,  among  the  mysteries  of  Nature,  which  baffie 
while  they  excite  inquiry." 

The  last  clause  of  this  quotation  expresses  the  unsatisfactoiy  state  of  the 
question;  yet  the  foregoing  examination  will,  we  think,  leave  only  three 
hypotheses  desei'ving  further  inquiiy :  viz.,  1.  the  existence  of  cilia,  or,  2.  of 
an  undulating  membrane ;  and  3.  the  operation  of  endosmose  and  exosmose, 
as  a  mechanical  cause.  To  our  apprehension,  the  presence  of  cilia,  perhaps 
ranged  only  along  the  sutural  lines,  has  not  been  completely  disproved  ;  and, 
on  the  other  hand,  considered  as  locomotive  organs,  cilia  have  the  great 
advantage  of  analogy  over  the  presumed  undulatory  membrane.  Do  not, 
indeed,  the  experiments  with  indigo,  recoimted  by  Siebold,  suggest  cilia  to 
be  the  active  agents  of  the  movements  recorded  ? 

The  rate  of  motion  of  the  Diatomeae  is  exceedingly  languid  and  slow; 
sometimes  it  amounts  to  no  more  than  an  oscillating  movement,  with  Httle 
or  no  change  of  place  ;  and  at  anothei*,  the  backward  and  forward  movements 
are  so  nearly  equal,  that  the  fnistule  makes  no  appreciable  advance.  Prof. 
Smith  has  measured  the  rate  of  motion  of  some  species,  and  remarks  that, 
however  vivacious  and  rapid  they  may  at  first  sight  seem,  yet,  when  con- 
sidered vdth  reference  to  the  high  magnifying  powers  employed,  and  the 
consequent  amplification  of  their  movements,  they  are  very  slow.  "  I  have 
noted  the  movements  of  several  species  with  the  aid  of  an  eye-piece  micro- 
meter and  a  seconds  watch,  and  found  that  one  of  the  most  rapid,  viz.  Bacil- 
laria  paradoxa,  moved  over  g- ott^^  ^^  ^^  ^^^^  ^^  ^  second ;  Pinnularia  radiosa, 
one  of  the  slowest,  over  .,  .^....th  of  an  inch  in  the  same  time  ;  and  that  the 
same  period  was  occupied  by  Pinmdaria  ohlonga  m  traversing  -ginroth  of  an 
inch,  Nitzschia  linearis  y-V^th  of  an  inch,  and  Pleurosigma  strigosum  ytwo^^ 
of  an  inch.  Or,  expressing  the  spaces  and  times  by  other  units,  we  find  that 
the  most  active  required  somewhat  more  than  three  minutes  to  accomplish 
movements  whose  sum  would  make  one  inch,  and  the  slowest  nearly  an  hour 
to  perform  the  same  feat." 

Before  quitting  the  subject  of  the  movements  of  the  Diatomeae,  we  would 
briefly  advert  to  the  peculiar  motion  of  some  species,  especially  of  BaciUaria 
paradoxa.  The  movements  of  this  organism,  as  the  specific  name  implies, 
are  paradoxical,  or  very  strange  in  character.  Mr.  Thwaites  essayed  to 
describe  what  indeed  can  be  rightly  apprehended  only  by  personal  ob- 
servation, in  the  following  words  (Proc.  of  Linn.  Soc.  i.  p.  311): — "When 
the  filaments  have  been  detached  from  the  plants  to  which  they  adhere,  a 
remarkable  motion  is  seen  to  commence  in  them.  The  first  indication  of  this 
consists  in  a  shght  movement  of  a  terminal  fnistule,  which  begins  to  slide 


OF  THE  DIATOME.E.  OO 

length^\dse  over  its  contiguous  fmstule  ;  the  second  acts  simultaneously  in  a 
similar  manner  mth  regard  to  the  third,  and  so  on  throughout  the  whole 
filament, — the  same  action  having  been  going  on  at  the  same  time  at  both 
ends  of  the  filament,  but  in  opposite  directions.  The  central  frustule  thus 
appears  to  remain  stationary,  or  nearly  so, — while  each  of  the  others  has 
moved  with  a  rapidity  increasing  with  its  distance  from  the  centre,  its  OAvn 
rate  of  movement  ha\ing  been  increased  by  the  addition  of  that  of  the  inde- 
pendent movement  of  each  fmstule  between  it  and  the  central  one.  This 
lateral  elongation  of  the  filament  continues  imtil  the  point  of  contact  between 
the  contiguous  frustules  is  reduced  to  a  veiy  small  portion  of  theii'  length, 
when  the  filament  is  again  contracted  by  the  fnistules  shding  back  again  as 
it  were  over  each  other ;  and  this  changed  direction  of  movement  proceeding, 
the  filament  is  again  di'awn  out  until  the  frustules  are  again  only  shghtly  in 
contact.  The  direction  of  the  movement  is  then  again  reversed,  and  con- 
tinues to  alternate  in  opposite  dii'ections,  the  time  occupied  in  passing  from 
the  elongation  in  one  direction  to  the  o^^posite  being  generally  about  45 
seconds.  If  a  filament  while  in  motion  be  forcibly  divided,  the  iminjured 
frustules  of  each  portion  continue  to  move  as  before,  proving  that  the  filament 
is  a  compoimd  structure,  notwithstanding  that  its  frustules  move  in  unison. 
When  the  filament  is  elongated  to  its  utmost  extent,  it  is  extremely  rigid,  and 
requires  some  comparatively  considerable  force  to  bend  it,  the  whole  filament 
moving  out  of  the  way  of  any  obstacle  rather  than  bending  or  separating  at  the 
joints.     A  higher  temperatiu'e  increases  the  rapidity  of  the  movement." 

To  this  account  Prof.  Smith  appends  these  observations : — "  The  motion 
here  so  accurately  described  is  not  essentially  diff'erent  from  that  noticeable 
in  many  of  the  free  species  of  Diatomeae,  the  pecuHarity  being  that  it  is 
here  exhibited  in  numerous  united  frustules ;  when  observed  in  a  band  of 
one  hundred  or  more  frustules,  the  singular  appearances  assumed  by  the 
filament  under  the  action  of  so  many  individuals  moving  at  one  time  in 
apparent  concert,  and  another  in  opposition,  never  fail  to  excite  astonish- 
ment." 

Mr.  Thwaites's  account  conveys  the  impression  that  the  movements  are 
always  regular :  but  this  is  not  the  case ;  for  Mr.  Ealfs  tells  us,  by  letter, 
that  both  Dr.  Bailey  and  himself  have  convinced  themselves  that  they  are 
at  many  times  irregular. 

Dr.  Donkin,  in  his  description  of  a  new  species  of  Bacillaria  he  names  B. 
cursoria  (J.  M.  S.  1858,  p.  27),  has  the  following  account  of  its  singular  move- 
ments : — "  When  the  filament  is  in  a  quiescent  state,  the  frustules  are  all  dra^Ti 
up  side  by  side,  their  extremities  being  all  in  a  line,  thus  forming  a  group. 
When  a  filament  previously  at  rest  resumes  its  activity,  the  movement]  is 
commenced  by  the  second  or  inner  fmstule  at  one  end  of  the  filament  gliding 
forward  along  the  contiguous  surface  of  t\iQ  first  or  outer  frustule  until  their 
opposite  extremities  overlap  each  other.  This  is  soon  followed  by  a  similar 
movement  of  the  third,  fom^h,  and  fifth,  &c.,  all  moving  forward  in  the  same 
direction,  and  each  fmstule  gliding  along  the  suiface  of  the  one  preceding  it, 
imtil  they  have  extended  themselves  into  a  lengthened  filament  or  chain.  In 
the  course  of  two  or  thi'ee  seconds  after  this  has  been  accomplished,  a  retrograde 
movement,  exactly  of  the  same  character,  begins  to  take  jDlace,  and  continues 
until  the  filament  has  retraced  its  course,  and  stretched  itself  out  in  a  direction 
exactly  opposite  to  the  position  it  had  previously  occupied.  This  phenomenon 
is  repeated  again  and  again ;  and  in  this  manner  the  whole  group  is  kept  in 
a  state  of  activity  for  an  indefinite  period  of  time ;  and  all  the  while,  if  no 
impediment  produces  irregularity,  the  outer  or  terminal  frustide,  next  to 
which  the  movement  commenced,  maintains  a  stationary  atul  fixed  position. 


56  GENEEAL  HISTOHY  OF  THE  INFTJSOEIA. 

"  The  rapidity  with  which  each  individual  frustiile  moves  is  in  direct  rati 
to  its  distance  from  the  terminal  stationary  frustnle,  being  most  rapid  at  the 
opposite  or  moving  extremity  of  the  filament.  On  this  account,  most  of  the 
friistules,  while  the  filament  is  moving  to  and  fro,  cross  a  line  drawn  at  right 
angles  to  the  middle  of  the  long  axis  of  the  stationary  frustule,  at  the  same 
instant  of  time,  afterwards  shooting  past  each  other  like  horses  on  a  race- 
course. 

"  The  force  with  which  the  filament  moves  is  very  great,  so  much  so  that 
I  have  observed  it  upset  and  shove  aside  a  large  fnistule  of  A.  arenaria,  n. 
sp.,  at  least  six  times  its  own  bulk,  obstructing  its  path.  This  force  is,  in  a 
great  measiu-e,  due  to  the  rapidity  with  which  the  frustules  move, — the  time 
which  a  filament,  even  of  considerable  length,  occupies  in  crossing  the  field 
of  the  microscope  being  only  a  few  seconds. 

"  Light  appears  to  be  a  necessary  stimulus  for  the  maintenance  of  this 
motion.  When  a  filament  in  active  motion  is  placed  in  the  dark  for  a  short 
period,  and  then  examined,  the  movement  is  seen  to  have  ceased,  but  again 
commences  when  the  filament  is  exposed  to  the  light  for  a  short  time.  Is 
not  this  singular  movement,  Tvith  which  the  present  species  is  endowed,  a 
vital  phenomenon,  and  independent  of  physical  causes  for  its  existence  ? 

'^  When  the  moving  extremity  becomes  entangled  in  any  kind  of  substance 
intercepting  its  coui'se,  the  opposite  or  stationary  extremity  commences  to 
move,  and  continues  to  do  so  until  the  entangled  extremity  is  set  free  ; 
sometimes,  in  such  instances,  a  frustule  in  the  centre  remains  fixed,  a  move- 
ment of  each  half  of  the  filament  in  opposite  directions,  on  either  side  of  it, 
taking  place.  But  all  these  irregularities  cease  as  soon  as  the  impediment 
has  been  got  rid  of. 

"  These  facts  lead  to  the  conclusion  that  the  present  species  is  a  true  Bacil- 
laria,  although  aiDparently  somewhat  anomalous  in  the  structure  of  its  frustule. 
The  gliding  movement  of  one  fi'ustule  over  the  contiguous  one  is  the  same  as 
is  observed  in  B.  paradoxa ;  but  it  difi'ers  from  this  latter  species  in  this 
essential  particular,  that  the  wlioU  of  its  filament  moves  on  one  side  of  a 
terminal  frustule  which  is  stationary, — while,  in  B.  paradoxa,  each  half  of  the 
filament  moves  in  opposite  directions  on  either  side  of  a  central  stationary 
frustule." 

The  movement  of  one  segTaent  upon  another  is  witnessed  in  other  con- 
catenate species,  but  in  a  less  degree,  where  the  medium  of  attachment  is 
limited  to  a  small  space,  as  in  those  several  genera  having  the  alternate  or 
opposite  angles  of  their  frustules  connected  by  a  link-like  isthmus,  e.  g. 
Diatoma,  Fragilaria,  Grammatophora,  &c. 

Nutritive  Fitnctions; — Supposed  Stomachs; — Circulation  of  Contents; — 
Kespiration. — The  nutrition  of  Diatomeas  is  provided  for  primarily  by  the 
endosmotic  and  exosmotic  action  going  on  through  the  '  foramina '  in  the 
silicious  epiderm,  whereby  fluid  material  laden  with  the  matters  necassary 
to  build  up  the  various  elements  of  the  endochrome  is  introduced  into  the 
organisms. 

On  the  first  appearance  of  a  frustule,  the  endochrome  is  homogeneous  and 
granular ;  but  as  time  advances,  granules  are  seen  to  congregate  in  certain 
parts,  and  globules  or  vesicles  of  various  size  speedily  develope  themselves, 
and  either  take  up  definite  positions  or  are  irregularly  diffused.  During 
these  changes  in  the  contents — during,  indeed,  the  entire  life  of  _  the  cell, 
under  the  influence  of  light,  oxygen  is  given  off,  and  the  gases  -with  which 
it  was  united  in  various  chemical  compounds  are  appropriated  to  the  purposes 
of  the  economy. 

The  veiT  fact  of  the  existence  of  the  silicious  epiderm,  thrown  off,  it  would 


OF  THE  DIATOME^.  57 

seem,  as  an  excretion  from  the  organic  membrane  of  the  frustiiles,  indicates 
the  activity  and  energy  of  the  nutritive  fimctions, — a  fact  further  demonstrated 
by  the  production  of  the  '  connecting  membrane/  and,  in  short,  by  the  whole 
process  of  reproduction,  whether  by  self-di^dsion  or  by  sporangia.  The  silica 
present  in  the  lorica  must  be  taken  up  by  the  organism  in  a  state  of  solu- 
tion ;  and  although  the  quantity  of  silica  dissolved  in  water  is  inconceivably 
small,  it  is  nevertheless  sufficient  to  supply  the  material  for  the  construction 
of  millions  of  Diatomaceous  shells,  even  in  a  short  time,  as  the  phenomena 
of  reproduction  and  the  rapid  appearance  of  these  structures  as  an  appre- 
ciable powder,  or  as  a  coloui'ing  matter  in  water,  prove.  "  It  is  probable,"  says 
Dr.  Gregory  {J.  M.  S.  1855,  p.  2),  "  that  as  fast  as  the  silex  is  extracted  from 
the  water  hj  them,  it  is  dissolved  from  the  rocks  or  earths  in  contact  mth 
the  water,  so  that  the  supply  never  fails ;"  and  we  may  add,  so  that  the 
quantity  never  accimiulates  beyond  the  very  minute  fi^actional  portion  chemists 
can  detect. 

Ehrenberg's  untenable  hypothesis  of  the  presence  of  stomach-sacs  and  of  an 
alimentary  canal  opening  externally  has  received  sufficient  attention  in  the 
history  ah^eady  given  (pp.  47, 48),  of  the  natiu^e  of  the  contents  of  the  Diatomeae 
and  of  their  investing  lorica.  "Were  other  considerations  needed,  the  absence 
at  times  of  any  such  vesicles  as  Ehrenberg  conceived  to  be  gastric  cells,  their 
occasional  coalescence,  and  the  phenomenon  of  cyclosis  or  the  circulation  of 
the  contents,  each  and  all  subjects  of  direct  obsei^ation,  might  be  appealed 
to  as  proofs  of  the  errors  that  great  naturalist  fell  into  respecting  the  internal 
organization  of  the  Diatomeae. 

The  phenomenon  of  cyclosis  has  been  observed  by  Niigeli  in  a  species  of 
Navicida,  and  in  one  of  GallioneUa  {Melosira)  (XY.  27),  and  by  Prof.  Smith 
in  other  Diatoms.  This  writer  says  {op.  cit.  i.  p.  xxi) — "  In  SurireUa  biseriata 
this  motion  has  been  more  especially  apparent ;  but  I  have  also  observed  it 
take  place  in  Nitzsclda  scalaris  and  Camj)i/lodiscus  scalaris.  This  cii^culation 
has  not,  however,  the  regularity  of  movement  so  conspicuous  in  the  Des- 
midieee,  and  is  of  too  ambiguous  a  character  to  fuiTiish  data  for  any  veiy  certain 
conclusions,  save  one,  viz.  that  the  Diatom  must  be  a  single  cell,  and  cannot 
contain  a  number  of  separate  organs,  such  as  have  been  alleged  to  occupy  its 
interior, — since  the  endochrome  moves  fi^eely  from  one  portion  of  the  frustule 
to  the  other,  approaching  and  receding  from  the  central  nucleus  unimpeded 
by  any  intervening  obstacle." 

Schultze,  in  his  contribution  on  the  movements  within  the  frustules  of 
Diatomeae  {Midi.  Arcliiv,  1858),  represents  them  to  occur  in  and  along  the 
finely  granular  threads  into  which  the  less  fluid  mucilaginous  portion  of  the 
endochrome  is  di^awn  out.  He  compares  the  movements  in  character  to 
those  of  the  '  variable  processes '  or  pseudopoda  of  Ehizopodes,  and  thereby 
assimilates  the  mucilaginous  films  of  Diatomaceous  fnistules  with  the  soft 
sarcode  of  those  simplest  animalcules, — a  similarity  countenanced  by  the  now 
weU-known  fact  of  an  Amoebiform  phase  in  the  cycle  of  development  of  some 
of  the  lower  Algae  {vide  section  on  Phytozoa).  The  cyclosis  in  plant-ceUs  is 
no  doubt  rightly  attributed  to  the  operation  of  the  vital  processes  of  nutrition 
and  of  the  so-called  respiration,  and  primarily  to  the  chemico-vital  action 
proceeding  by  the  medium  of  the  chlorophyU-globules  ;  and  it  seems  most  con- 
sonant with  the  teachings  of  science  to  assign  the  less  active  and  less  complete 
and  regular  internal  movements  of  the  Diatomeae  also  to  the  similar  vital 
forces, — the  coloured  corpuscles,  it  may  be,  acting  here  likewise  as  the  prime 
mover.  We  are  aware  that  the  nucleus  has  been  represented  to  be  the  first 
source  of  the  movements  in  plant- cells,  since  the  current  seems  to  flow  from 
and  to  return  to  it  in  many  cases ;  but  this  phenomenon  is  explicable  in 


58  GENEEAL  HISTORY  OP  THE  INFUSOllIA. 

another  way,  by  admitting  the  disposition  of  the  mucous  threads  as  displayed 
by  Schultze,  extending  as  they  do  from  the  nucleus  on  all  sides,  and  serving 
at  the  same  time  to  limit  and  to  direct  the  movements  taking  place  within 
and  by  them.  We  have  not  adverted  to  ciliary  action  as  the  cause,  for ;  so 
far  as  we  can  gather,  Mr.  Osborne  and  Mr.  Jabez  Hogg  have  failed  to  impress 
many  naturalists  with  the  fact  of  its  existence  and  operation  in  Diatoms. 

Lastly,  Schultze  remarks  that,  to  see  the  mucilaginous  threads  and  the 
internal  movements,  living  and  fi^esh  specimens  are  needed ;  for  they  are  soon 
arrested  when  the  frustules  are  removed  from  their  natui-al  habitats,  and  are 
quite  lost  to  vision  when  they  become  diy.  Hence  it  is,  no  doubt,  that  no 
previous  observer  has  detected  and  rightly  apprehended  the  facts  enunciated 
by  Schultze. 

The  so-called  function  of  respiration  is  evinced  in  the  fixing  of  the  carbon 
of  the  carbonic  acid  and  in  the  disengagement  of  oxygen  gas ;  but  this  is 
rather  an  act  of  nutrition,  and  resembles  that  silent  and  invisible  disengage- 
ment of  certain  particles,  and  the  rearrangement  of  others,  which  proceed  in 
the  formation  and  in  the  removal  of  worn-out  tissues  in  higher  animals. 

MuLTiPLiCATiois",  REPRonrcTio:?^,  AifD  Developmej^t  of  DiATOMEiE. — Among 
the  modes  of  reproduction  of  the  Diatomeee,  self- division  has  usually  been 
accoimted  one,  but  erroneously  so,  since  this  process  is  no  more  than  a  mul- 
tiplication of  an  individual  cell,  and  completely  homologous  with  the  process 
of  cell-fission  exhibited  in  the  construction  of  animal  and  vegetable  tissues 
in  general.  The  peculiarity  in  the  self-division  of  the  Diatomeae,  i  e.  among 
the  free  simple  beings,  is,  that  the  division  is  followed  by  separation ;  for 
each  cell,  instead  of  imiting  Avith  its  neighbours  in  the  formation  of  a  tissue, 
commences  an  independent  existence.  Self-division  in  one  direction,  not 
followed  by  separation,  produces  the  filamentary  or  concatenated  Diatomeae, 
whilst  the  abundant  excretion  of  a  mucus  around  the  dividing  frustules,  and 
its  persistence,  give  rise  to  the  frondose  genera,  which  make  an  approach 
towards  the  character  of  vegetable  cellular  tissue, — each  ceU,  however,  retain- 
ing an  independent  vitality  greatly  more  pronounced  than  in  the  latter. 

The  process  of  self-fission  or  deduplication  in  this  family  resembles  in  all 
essential  particulars  that  in  other  vegetable  cells  (XY.  28,  a,  h,  c).  Preparatory 
to  its  visible  occurrence,  or  rather  simultaneously  Tvith  certain  changes  in  the 
interior,  the  valves  separate  by  the  progressive  gro^i;h  of  the  connecting 
membrane.  The  nucleus  within  is  observed  to  divide  into  two  portions,  each 
of  which  eventually  becomes  detached  from  the  other,  and,  in  Prof.  Owen's 
language,  serves  as  a  centre  of  spermatic  force,  and  induces  an  aggregation 
of  the  granules  of  the  endochrome  about  it.  Whilst  this  separation  of  the 
nucleus  and  of  the  general  contents  is  going  forward,  the  lining  or  primordial 
membrane  of  the  cell  becomes  doubled  inwards  in  the  entire  cii'cumference 
along  the  line  of  division,  and  advances  gradually  until  it  at  length  forms  a 
complete  septum,  cutting  the  original  single  cell  into  two.  This  septum  is 
actually  double ;  and  in  each  lamina  a  deposit  of  silicious  material  speedily 
proceeds,  so  as  to  produce  two  new  valves,  each  opposed  to,  and  immediately 
continuous  around  its  circumference  with,  one  of  the  two  original  valves. 
Thus,  on  the  completion  of  this  process  of  deduplication,  two  finistules  result, 
awaiting  only  the  final  act  of  separation  to  enter  on  an  independent  exist- 
ence and  to  repeat  the  like  series  of  phenomena,  and  so  on  through  a 
seemingly  almost  endless  chain,  to  perj)etuate  the  existence  of  the  particular 
species  or  individual.  (See  Meneghini's  account  of  the  process  and  peculiari- 
ties of  self-di\dsion  in  this  class,  in  the  examination  of  the  argimients  for  the 
animality  of  the  Diatomaceae,  in  a  subsequent  page.)  The  true  nature,  there- 
fore, of  this  process  of  self-di\-ision  being  an  extension,  not  a  renewal,  of 


OF  THE  DIAT03IEJE.  59 

individual  life,  has  been  justly  represented  by  Mr.  Thwaites  as  an  act  of 
gemmation,  not  of  reproduction. 

In  the  coiu\se  of  self- division,  in  some  instances  at  least,  a  mucous  or 
muco-gelatinous  matter  is  thrown  out  around  the  fiiistules  engaged.  This 
cii'cumstance  did  not  escape  the  notice  of  Nageli  ;  and  Prof.  Smith  (Si/nopsiSj 
i.  p.  62)  has,  after  noting  it  in  previous  pages  as'a  common  phenomenon  in  the 
family,  thus  referred  to  it  in  the  genus  Pleiovsigma  : — "  While  self-division 
is  actively  going  forward,  the  mucus  generated  by  the  dividing  fi^ustules  is 
often  so  considerable  as  to  produce  the  appearance  and  effect  of  a  distinct 
frond,  which  assumes  the  form  of  a  thin  pellicle  of  some  little  tenacity.  At 
other  times,  when  the  mucous  secretion  does  not  assume  the  continuity  of  a 
pellicle,  it  invests  the  individual  frustule  with  a  transparent  envelope,  which 
has  the  appearance  of  an  exterior  membrane,  and  has  been  sometimes  mis- 
taken for  such.  On  one  occasion  I  also  met  with  the  fnistules  of  P.  Hippo- 
campus enclosed  in  mucous  or  gelatinoiLS  tubes,  precisely  like  those  of  a 
Colletonema ;  but  these  conditions  must  be  regarded,  for  the  present  at  least, 
as  temporary  or  accidental,  and  cannot  be  admitted  into  the  specific  or  generic 
descriptions." 

The  process  of  self- division  is  affected  in  some  unimportant  particulars  by 
the  figure  and  habits  of  certain  genera.  Thus  in  one  section  of  the  MelosireWy 
the  fnistules  of  which  have  convex  ends,  Mr.  Ealfs  points  out  (A.  iV.  H. 
xii.  p.  347)  that  the  central  line  is  more  strongly  marked,  and  seems  to 
divide  the  frustule  into  two  equal  portions.  It  becomes  broader,  and  at  length 
double,  and  ultimately  an  intermediate  growth  separates  the  two  halves  of 
the  fnistule,  which,  during  this  process,  do  not  increase  in  size ;  but  when 
the  intermediate  space  is  equal  to  the  diameter  of  the  original  frustule,  two 
new  frustules  are  formed,  by  the  addition  of  two  hemispheres  on  the  inner 
sides  of  the  separated  portions.  The  outer  silicious  covering  still  remaining, 
the  fnistules  are  connected  in  pairs,  and  appear  like  two  globules  within  a 
joint,  as  they  are  characterized  by  Harvey  in  Melosira  nummuloides,  and  by 
Carmichael  in  M.  glohifera.  The  above  description  belongs  more  particularly 
to  M.  nmnmulokles ;  but  the  process  in  the  other  species  of  this  section  is  the 
same  :  a  series  of  changes,  nearly  similar,  occurs  in  Isthmia. 

"  In  this  genus,"  the  author  quoted  says,  "■  the  mode  of  growth  is  very 
curious.  As  in  most  of  the  Diatomeae,  the  plant  increases  by  a  division  of 
the  fnistules  ;  but  in  this  genus,  as  also  in  Biddiilphm  and  Amphitetras 
(and  in  the  Achnanthece),  two  new  fi^ustules  are  formed  within  the  old  one, 
and  as  they  enlarge,  ruptui^e  it,  when  it  falls  off.  In  these  the  front  portion 
is  at  first  very  narrow,  and  merely  a  broad  line,  but  it  increases  greatly  in 
breadth  until  the  new  frustules  are  fiilly  formed."  In  this  description  and 
explanation  the  widening  band  or  fi'ont  portion  mentioned  is  in  fact  the 
*  connecting  membrane '  of  Prof.  Smith,  which,  in  the  genera  named,  has 
an  extra  development,  "  an  extension  beyond  the  sutures  of  the  valves,"  and 
also  an  unusual  persistence,  retaining  the  two  frustules  together  after  self- 
division,  in  such  a  manner  that  they  seem  to  be  enclosed  Avithin  an  original 
single  frustule,  just  as  Mr.  Ealfs  describes. 

This  longer  persistence  of  the  connecting  membrane  has  been  noted  by 
Prof.  Smith  {A.  N.  H.  1851,  p.  4),  who  writes—''  In  some  cases,  by  the 
new,  or  rather  semi-new  frustules  proceeding  immediately  to  repeat  the 
process  [of  self-division],  the  connecting  membrane  is  thi^own  off  and  disap- 
pears ;  in  others  it  remains  for  some  time,  linking  the  fi'ustules  in  paii's,  as 
in  Melosira  and  OdonteUa.'" 

Another  peculiarity,  again,  not  unfi-equently  obtains  in  this  process  of  self- 
fission,  viz.  a  departure  from  the  prevailing  law  of  similarity  which  exists 


60  GENERAL  HISTORY  OF  THE  rNFTJSORIA. 

between  the  new  valve  and  the  parent  one  with  which  it  is  united  in  the 
newly-created  frustule.  The  newly- developed  segment  occasionally  acquires 
slightly  greater  dimensions, — a  fact  best  exhibited  in  the  filamentous  genera, 
since  in  them  it  gives  rise  to  an  evident  irregularity  in  the  chain,  affecting  its 
width.  Yet,  as  Prof.  Smith  remarks  (i.  p.  xxvi),  "  This  increase  is  so  small, 
that  in  a  filament  of  many  hundred  frustules,  the  enlargement  is  scarcely 
appreciable.  The  rapid  attenuation  represented  by  some  authors  in  the 
filaments  of  the  FragilaricB  must  therefore  be  attributed  to  the  deceptive 
appearance  presented  by  a  compressed  band  when  slightly  twisted,  the  sem- 
blance of  attenuation  being  thus  given  to  the  portions  which  are  presented 
in  an  oblique  direction  to  the  eye  of  the  observer ....  Starting  from  a  single 
frustule,  it  will  be  at  once  apparent,  that  if  its  valves  remain  unaltered  in 
size,  while  the  cell-membrane  experiences  repeated  self-di\ision,  we  shall 
have  two  frustules  constantly  retaining  theii'  original  dimensions,  four  slightly 
increased,  eight  somewhat  larger,  and  so  on  in  a  geometrical  ratio,  which 
will  soon  present  us  with  an  innumerable  multitude  containing  individuals  in 
every  stage,  but  in  which  the  larger  sizes  preponderate  over  the  smaller  ;  and 
such  are  the  circumstances  ordinarily  found  to  attend  the  presence  of  large 
numbers  of  these  organisms." 

Mr.  Balfs  has  favoured  us  ^ith  the  follomng  remarks  on  this  subject  in 
letters.  He  writes  (March  1856) — *'  In  a  recent  number  of  the  Ann.  Nat. 
Hist,  Mr.  Carter  expresses  his  belief  that  the  fnistules  of  Diatomaceae  gra- 
dually become  smaller  by  division,  and  that  it  requires  the  sporangial  frustule 
from  time  to  time  to  keep  them  the  proper  size.  This  I  cannot  admit ;  for 
any  person  who  will  take  the  trouble  to  watch  a  species  of  Gomphonema 
from  its  fii'st  appearance  in  spring,  as  a  scarcely  \isible  fringe  to  aquatic 
plants,  will  observe  not  only  increase  of  mass,  but  also  enlargement  of  the 
frustules.  If  Mr.  Carter  is  right,  the  filament  in  Fragilaria  would  be  veiy 
unequal :  for  instance,  as  the  first-formed  frustule  could  not  decrease,  and  as 
its  segments  after  division  would  always  form  the  two  ends  of  the  filament, 
they  should  be  the  largest,  then  the  adjacent  valves  of  the  two  central  frustules 
of  the  filament  the  next  largest,  and  so  on."  In  a  subsequent  letter  the 
same  distinguished  authority  writes : — ''  I  see  that  Prof.  Smith,  in  his 
Synopsis,  p.  xxvi,  takes  the  contrary  view  to  Mr.  Carter,  and  considers  that 
the  frustules  do  not  grow  after  they  are  fully  formed,  but  that,  in  dividing, 
the  new  frustules  may  slightly  increase  in  size.  It  is  thus  that  he  accounts 
"  for  the  varying  breadth  of  the  bands  in  the  filamentous  species,  and  the 
diversity  of  size  in  the  frustules  of  the  free  forms."  If  he  is  correct,  his 
opinion  is  still  more  adverse  to  Mr.  Carter's  views  respecting  the  frustules 
formed  after  self- division.  But  I  doubt  also  the  correctness  of  Mr.  Smith's 
views.  He  himself  states  that  "  the  enlargement  is  scarcelj^  appreciable ;" 
and  yet  we  find  a  vast  difference  of  size  in  the  frustules  of  the  same  gather- 
ing. The  filaments  are  so  fragile  in  Fragilaria,  and  even  in  Himantidium, 
that  it  is  very  difficult  to  determine  whether  the  frustules  in  the  same  fila- 
ment do  diff'er  much  ia  size,  and  whether,  if  they  do,  the  variations  are  alter- 
nating or  irregular,  as  would  be  the  case  if  either  Prof.  Smith  or  Mr.  Carter 
be  correct. 

The  rate  of  production  of  specimens  of  Diatomeae,  even  by  this  one  pro- 
cess of  simple  self-division,  is  something  really  extraordinary.  So  soon  as 
a  frustule  is  divided  into  two,  each  of  the  latter  at  once  proceeds  with 
the  act  of  self- division ;  so  that,  to  use  Prof.  Smith's  approximative  cal- 
culation of  the  possible  rapidity  of  multiplication,  supposing  the  process 
to  occupy,  in  any  single  instance,  twenty-four  hours,  "  we  should  have,  as 
the   progeny  of   a  single  frustule,  the  amazing  number  of  one  thousand 


OF  THE  DIATOME-E.  61 

millions  in  a  single  month, — a  circumstance  which  will  in  some  degree  explain 
the  sudden,  or  at  least  rapid  appearance  of  vast  numbers  of  these  organisms 
in  localities  where  they  were,  but  a  short  time  previously,  either  unrecognized 
or  only  sparingly  diffused." 

This  multiplication  by  self- division  now  described,  is  generally  supposed, 
after  a  time,  so  to  speak,  to  exhaust  itself,  and  thereby  to  render  necessary 
other  plans  of  propagating  species.  That  some  other  modes  do  really  exist 
is  suggested  by  the  fact  of  the  considerable  variations  of  size  of  frustules  of 
the  same  species  obtained  at  one  time  from  the  same  locality,  and  moreover 
by  diversities  in  the  relative  distance  and  in  the  delicacy  of  the  strise  of  the 
surface.  One  such  mode  of  propagation  Mr.  Thwaites  has  demonstrated  to 
consist  in  the  production  of  sporangial  frustules  by  a  process  of  conjugation 
analogous  to  that  in  the  Desmidiese  and  many  other  Algae. 

Con jroATio^r. — The  method  of  conjugation,  although  essentially  alike  in  all 
cases,  exhibits  several  important  modifications  in  the  genera  of  this  family. 
These  were  more  or  less  clearly  perceived  by  Mr.  Thwaites,  who  spoke  of  them 
as  exceptional  varieties  ;  but  to  Mr.  Smith  belongs  the  credit  of  reducing  all 
of  them  under  four  principal  forms:  viz.,  1.  That  in  which  two  parent  frustules 
produce  two  sporangia  by  conjugation,  as  mEpitliemia,Cocconema,Gomjphonema, 
Encyonema,  and  Colletonema.  2.  Two  parent  frustules  generate  a  single  spo- 
rangium, e.  g.  in  Himantidium.  3.  ''  The  valves  (vol.  ii.  p.  xii)  of  a  single 
frustule  separate,  the  contents  set  free  rapidly  increase  in  bulk,  and  finally 
become  condensed  into  a  single  sporangium.  This  may  be  seen  in  Cocconeis, 
CijcIoteUa,  Melosira,  Orthosira,  and  Schizonema. 

"  In  Melosira  nummuloides,  M.  Borrerii,  and  M.  subflexilis,  the  second  valve 
of  the  conjugating  frustule  is  rarely  found  united  to  the  mucus  surrounding 
the  sporangium,  the  conjugation  taking  place  only  in  the  last  frustule  of  the 
filament ;  but  in  Melosira  varians  and  Orthosira  orichalcea,  conjugation  taking 
place  throughout  the  entire  filament,  both  valves  are  usually  found  adherent 
to  the  sporangium  or  its  surrounding  mucus. 

"  From  a  single  frustule,  as  in  the  last  method,  two  sporangia  are  produced 
in  the  process  of  conjugation  :  this  takes  place  in  Achnanthes  and  Bhahdonema.^' 

In  describing  the  process  as  generally  as  possible,  we  cannot  do  better  than 
follow  Mr.  Thwaites's  account,  although  it  is  illustrated  by  an  example  taken 
from  the  fii^st  categorj"  of  variations.  "  For  the  most  part,"  he  tells  us, 
*'  conjugation  in  the  Diatomeee,  as  in  the  Desmidieae,  consists  in  the  union 
of  the  endochi'ome  of  two  approximated  fronds, — this  mixed  endochrome 
developing  around  itself  a  proper  membrane,  and  thus  becoming  converted 
into  the  sporangium.  In  a  veiy  early  stage  of  the  process,  the  conjugated 
fnistules,  as  in  Eunotia  turgida,  have  their  concave  surfaces  in  nearly  close 
apposition  (XI.  1),  and  from  each  of  these  surfaces  two  protuberances  arise, 
which  meet  two  similar  ones  in  the  opposite  frustule  (XI.  3) ;  these  protu- 
berances indicate  the  future  channels  of  communication  by  which  the  endo- 
chrome of  the  two  fnistules  becomes  united,  as  well  as  the  spot  where  is 
subsequently  developed  the  double  sporangium,  or  rather  the  two  sporangia. 
A  front  view  of  two  frustules  at  the  same  period  shows  each  of  them  to  have 
divided  longitudinally  into  two  halves  (XI.  4),  which,  though  some  distance 
apart,  are  stiU  held  together  by  a  very  delicate  membrane :  this,  however, 
soon  disappears. 

''  The  mixed  endochrome  occurs,  at  first,  as  two  irregular  masses  between 
the  connected  frustules ;  but  these  masses  shortly  become  covered,  each  with 
a  smooth  cyUndiical  membrane, — the  young  sporangia,  which  gradually 
increase  in  length  (XI.  5,  6),  retaining  nearly  a  cjdindi'ical  fonn  (XI.  7), 
until  they  far  exceed  in  dimension  the  parent  frustules,  and  at  length,  when 


62  GENERAL  HISTORY  OF  THE  INFUSORIA. 

matm-e,  become,  like  them,  transversely  striated  upon  the  surface  (XI.  8). 
Around  the  whole  structure  a  considerable  quantity  of  mucus  has,  during 
this  time,  been  developed,  by  which  the  empty  frastiiles  are  held  attached  to 
the  sporangia  (XI.  5-8).'* 

The  variations  in  the  process  are  aUuded  to  in  the  follo^'ing  extracts  from 
the  same  eminent  observer's  papers  : — "  In  different  genera,  slight  variations 
are  met  with  in  the  method  of  conjugation :  thus,  in  some  species  of  Gom- 
phonema  the  sporangia  lie  in  a  direction  parallel  to  the  empty  frustules, 
instead  of  across  them,  as  described  in  Eunotia  turgida.  Again,  there  are 
examples  (in  Gomjphonema  minutissimmn  and  Fragilaria  pectinalis)  where, 
instead  of  the  conjugated  frustules  separating  into  two  halves,  only  a  slit 
appears  at  one  end,  to  serve  for  the  escape  of  the  endochrome.  Instead  also 
of  the  pail'  of  conjugated  frastules  producing  between  them  two  sporangia, 
they  may  develope  but  a  single  one,  as  happens  in  Fmgilaria  pectinalis.  In 
this  species,  too,  the  sporangium,  at  first  cylindrical,  soon  assumes  a  flattened, 
somewhat  quadrangular  form,  and  in  many  cases  undergoes  fissiparous  divi- 
sion before  it  has  put  on  the  exact  appearance  of  the  frustule  of  a  Fragilaria. 

"The  Melosirece  (GaUionellce,  Ehr.)  and  the  Biddulphice,^^  Mr.  Thwaites 
remarks,  "  would  seem,  in  their  development  of  sporangia,  to  offer  an  excep- 
tion to  most  Diatomeae  ;  for  in  those  genera  no  evident  conjugation  has  been 
seen.  However,  something  analogous  to  it  must  take  place  ;  for,  excepting 
the  mixture  of  endochromes  of  two  cells,  the  phenomena  are  of  precisely 
similar  character.  Thus,  instead  of  the  conjugation  of  two  fi-ustules  (XV. 
29,  a,  h,  c,  d,  32,  33),  a  change  takes  place  in  the  endochrome  of  a  single 
frustule, — that  is,  a  disturbance  of  its  pre\ious  arrangement,  a  moving 
towards  the  centre  of  the  frustule,  and  a  rapid  increase  in  its  quantity: 
subsequently  to  this  it  becomes  a  sporangium ;  and  out  of  this  are  developed 
sporangial  frustules,  as  in  the  other  Diatomeae.  In  a  single  cell,  therefore, 
a  process  physiologically  precisely  similar  to  that  occurring  between  two 
conjugating  cells  takes  place ;  and  it  is  not  difficult  to  believe,  taking  into 
view  the  secondary  character  of  ceU-membrane,  that  the  two  kinds  of  endo- 
chrome may  be  developed  at  the  opposite  ends  of  one  frustule,  as  easily  as  in 
two  contiguous  frustules,  and  give  rise  to  the  same  phenomena  as  ordinary 
conjugation." 

Fui*ther,  in  his  notes  on  Schizonema  suhcohcerens,  Mr.  Thwaites  writes, — 
"  The  sporangia  of  this  species  are  produced  by  the  conjugation  of  a  pair  of 
frustules  outside  the  filaments  ;  but  sporangial  frustules  are  frequently  found 
in  a  filament  intermixed  with  ordinaiy  frustules,  from  which  they  differ  only 
in  size."  - 

Dr.  Giiffith  and  !Mr.  Carter,  moreover,  have  portrayed  peculiarities  in 
the  conjugating  process,  which  Prof.  Smith  can  neither  explain  nor  confii'm, 
and  is  equally  unable  to  reduce  under  either  of  the  leading  variations  he  has 
defined.  The  first-named  natui-alist  stated  that  in  the  conjugation  of  a 
species  of  Navicula  (amphirhynchus  ?)  a  silicious  sheath  enveloped  the  spo- 
rangial frustule,  indestructible  by  heat  and  nitric  acid.  "  It  is,"  he  writes, 
"  colourless,  elongate,  rounded  at  the  ends,  and  furnished  with  coarse  trans- 
vei-se  striae  or  depressions,  through  which  the  line  of  fracture  runs  when  the 
object  is  crushed."  This  account  seems  to  Prof.  Smith  erroneous ;  and  he 
suggests  that  this  sheath  "  may  probably  have  been  an  appearance  resulting 
from  the  condensation  and  corrugation  of  the  mucus  developed  around  the 
reproductive  body."  This  conclusion  Dr.  Griffiths  declares  untenable,  since 
no  kind  of  mucus  wiU  resist  the  action  of  a  red  heat  and  nitric  acid.  The 
specimen  examined  was,  besides,  not  an  isolated  one,  but  hundreds  such  were 
present"  (A.  N.  H.  xvi.  92). 


OF  THE  DIATOME.E.  63 

Prof.  Smith  thus  alludes  to  Mr.  Carter's  \-iews  : — ''  The  cii'cumstance 
dwelt  upon  by  Mr.  Carter  as  having  an  important  bearing  upon  the  rationale 
of  the  process,  viz.  that  one  of  the  conjugating  finistules  is  invariablj^  smaller 
than  the  other,  is  altogether  at  variance  -^^ith  my  experience,  and  is  totally 
irreconcilable  with  the  process  as  it  occurs  in  the  genera  mentioned  under 
the  third  and  foui'th  classes.  1  am  therefore  disposed  to  believe  that  the 
difference  in  size  noticed  by  Mr.  Carter  was  a  mere  accidental  diversity,  and 
of  no  essential  signification." 

The  four  typical  modes  of  conjugation  established  by  Prof.  Smith  have 
their  occuiTence  thus  explained  (>Sywops.  ii.  p.  xiii) : — "  The  functions  of 
life  and  growth  are  not  suspended  dimng  the  act  of  conjugation ;  and 
in  consequence  self-division  may  take  place  at  any  stage  of  the  process 
which  accompanies  the  formation  of  the  reproductive  body,  or  the  latter 
process  may  intnide  upon,  or  arrest  any  step  in  the  progress  of  self-divi- 
sion. 

*'  In  the  fii'st  mode  of  conjugation,  as  occurring  in  Epithemia,  &c.,  self- 
division  may  be  regarded  as  in  the  earliest  stage  of  its  progress,  which  merely 
involves  the  separation  of  the  endochrome  of  the  parent  frustules  into  two 
portions,  but  does  not  include  such  a  differentiation  of  these  portions  as 
renders  them  capable  of  the  conjugative  act :  the  endochrome  capable  of 
conjugating  with  these  segregated  portions  must  be  sought  for  in  other 
frustules ;  hence  the  process  in  these  genera  involves  the  presence  of  two 
parent  frustules,  and  results  in  the  production  of  two  sporangia. 

"  In  the  second  mode,  met  with  in  Himantidium,  the  progress  of  separa- 
tion is  arrested  at  a  still  earlier  stage ;  no  differentiation  has  taken  place, 
and  conjugation  intervening,  necessitates  the  union  of  the  entire  contents  of 
two  parent  frustules  to  form  a  single  sporangium. 

"  In  the  third  mode,  the  progress  of  the  separation  of  the  endochrome  in 
the  parent  frustule  must  be  considered  as  so  far  advanced  that  complete 
differentiation  has  taken  place.  In  eveiy  respect  but  the  formation  of  new 
valves,  self- division  has  been  completed ;  the  incomplete  fnistules  are  there- 
fore prepared  for  conjugation,  which,  intervening  at  this  stage,  leads  the 
observer  to  believe  that  but  one  fi-ustule  has  been  concerned  in  the  produc- 
tion of  the  single  sporangium.  This  we  see  in  Melosira  and  the  other  genera 
mentioned  under  this  class. 

"And  lastly,  self-division  occurring  during  the  progress  of  conjugation, 
the  endochrome  becomes  segregated  in  the  veiy  act  of  intermingling,  and  a 
single  frustule,  whose  contents  have  been  abeady  differentiated,  gives  rise  to 
two  sporangia,  as  in  Achnaiithes  and  Rhahdonema . 

"  Nor  is  the  self-dividing  disposition  in  aU  eases  permanently  arrested  by 
the  complete  formation  of  the  sporangium.  Having  assumed  the  form  of  the 
parent  frustules,  with  a  great  increase  in  size  (the  enlargement  in  dimen- 
sions being  in  some  cases  due  to  the  accumulation  of  the  contents  of  the  two 
conjugating  frustules,  and  in  others  to  a  rapid  assimilation  of  nutritive 
material  from  the  surrounding  medium),  the  sporangial  frustule  immediately 
submits  to  self- division,  and  by  the  repetition  of  this  act  developes  a  series 
of  fnistules  equal  in  size  to  the  original  product  of  the  conjugating  process. 
This  is  notably  the  case  in  the  filamentous  species,  as  may  be  easily  seen 
in  Melosira,  in  Orthosira,  and  in  Himantidium.  How  far  this  self-division 
may  be  carried  in  the  sporangial  frustules  is  at  present  unknown  ;  it  is  pro- 
bably of  short  duration,  as  we  rarely  meet  with  any  considerable  number  of 
frustules  characterized  by  the  enlarged  size  of  the  sporangial  form.  In  most 
cases  an  arrest  of  growth,  and  consequently  of  self- division,  seems  imme- 
diately to  follow  the  complete  formation  of  the  sporangia,  and  the  reproduc- 


B4  GENERAL  HISTOEY  OF  THE  INFT7S0EIA. 

tive  body  assumes  the  quiescent  character  wliich  belongs  to  the  seed  of  the 
higher  plant,  its  Yital  function  remaining  dormant  until  circumstances  favour 
its  furthei;  development  and  the  production  of  the  young  frustules  of  which 
it  is  the  destined  parent. 

'^  In  the  gathering  of  Cocconema  Cistula  made  in  April  1852,  which  con- 
tained numerous  instances  of  the  conjugating  process,  I  observed  the  frequent 
occurrence  of  cysts  enclosing  minute  bodies,  variable  in  their  number  and 
size,  and  many  of  which  had  the  outline  and  markings  of  the  surrounding 
forms,  and  were  obviously  young  frustules  of  the  Cocconema.  It  would  appear 
from  the  figui^es  [appended  to  this  account],  that  the  production  of  the  j^oung 
frustules  is  preceded  by  the  separation  and  throwing  off  of  the  silicious  valves 
of  the  sporangium,  and  the  constriction  or  enlargement  of  its  primordial 
utricle,  according  to  the  number  of  young  frustules  originating  in  its  pro- 
toplasmic contents.  In  this  gathering,  forms  of  every  size  intermediate 
between  the  minutest  frustule  in  the  cyst  and  the  ordinary  frustules  engaged 
in  the  conjugating  process  were  easily  to  be  detected ;  and  the  conclusion 
was  inevitable,  that  the  cysts  and  their  contents  were  sporangia  of  the  species 
with  which  they  were  associated,  and  indicated  the  several  stages  of  the  re- 
productive process." 

Since  the  preceding  account  of  conjugation  was  written,  a  valuable,  although 
not  a  very  lucid,  contribution  on  the  subject  has  appeared  by  Dr.  Hofmeister, 
in  the  Reports  of  the  Saxony  Natural  Histor}^  Society  for  1857,  and  has  been 
translated  by  Prof.  Henfrey  in  the  A.  N.  H.  for  January  1858.  Prom  this 
we  extract  the  following  as  supplementary  to  the  previously-written  history 
of  the  conjugation-process  and  of  self-fission,  as  well  of  the  Desmidieae  (p. 11) 
as  of  the  Diatomeae : — 

''  Conjugation  is  far  more  rarely  met  with  in  the  Diatomeae  than  in  the 
Desmidieae.  It  appears  that  this  process  occurs  here  only  at  particular 
epochs,  differing  according  to  the  seasons,  happening  simultaneously  in  all 
individuals,  and  quickly  completed.  Frequently  as  indications  of  conjugation 
having  taken  place  have  been  met  with  (the  occuiTence  of  individuals  of  the 
same  species,  of  remarkable  diversity  of  size,  side  by  side,  in  free  Diatomeae, 
e.  g.  Pinnularia  virklis,  Surirella  hifrons,  Staurosigma  lacustre,  all  the  year 
round,  besides  the  occurrence  of  shorter  or  longer  rows  of  cells  of  about 
double  the  diameter,  in  the  bands,  of  the  forms  remaining  connected  by  the 
lateral  surfaces,  e.  g.  Mehsira,  Poclosira),  yet  it  has  seldom  happened  that 
they  have  been  met  with  in  the  moment  of  conjugation. 

"  Since  the  classic  researches  of  Thwaites  upon  this  subject,  the  knowledge 
of  it  has  on  the  whole  been  but  little  advanced  by  the  observations  of  Focke 
(conjugation  of  Surirella)^  Griffith  (conjugation  of  Navkida),  W.  Smith  and 
Carter  (conjugation  of  Cocconeis,  Cijmhella,  Amphora).  The  following  cases 
have  been  observed : — "  Formation  of  a  single  conjugation-ceU,  dividing  very 
soon  after  its  origin  :  in  Himantidium  pectorale,  Cymhella  Kiitzingiana,  Cocco- 
neis Pediculus,  Cocconeis  Placentida,  Oomplionema  lanceolatum,  Schizonema 
GreviUii,  Orthosira  oricJialcea,  0.  DicTciei,  remarkable  from  the  repeated  throw- 
ing-off  of  the  coats  of  the  conjugation-ceU,  the  cracked  halves  of  which  clothed 
the  conical  ends  of  the  conjugation -cell  in  shape  of  funnels ;  Orthosii^a  va- 
rians,  Surirella  hifrons,  and  a  Navicida  not  specifically  determined.  Here 
belongs  also  the  only  conjugation  of  a  Diatomacean  that  I  have  seen,  that  of 
Cyclotella  operculata,  conjugation- cells  of  which,  with  adherent  empty  coats 
of  the  mother-ceUs,  I  found  abundantly  in  ditches  of  a  marshy  meadow  not 
far  from  Leipsic,  in  October  1852.  They  were  not  distinguishable  in  any 
essential  respect  fi^om  the  Cyclotella  Kiitzingiana  figured  by  Thwaites. 

"  Next  to  these  cases  of  the  formation  in  the  first  place  of  only  one  conju- 


OF  THE  DIATOilE^.  65 

gation-cell,  come  a  series  of  observations  in  which  two  new  cells  were  seen 
between  the  empty  conjugated  mother- cells,  without  any  convincing  evidence 
being  offered  of  a  division  of  the  mother-cells  having  occurred  just  before 
conjugation,  as  in  the  cases  hereafter  to  be  mentioned, — where,  rather,  the 
position  of  the  empty  cells  in  relation  to  the  conjugation- cells,  and  the  affinity 
of  the  forms  in  question  to  some  in  which  the  entire  development  has  been 
obsei^ed,  render  it  probable  that  the  unicellular  condition  of  the  conjugation- 
cell  has  hitherto  escaped  obsei'vation.  In  tliis  group  are  to  be  counted  Coc- 
conema  lanceolatum,  C.  Cistula,  GompJionema  dichotomum,  G.  lanceolatum,  G. 
marinum,  AchnantJies  longipes,  Rhahdonema  arcuatum,  ColUtonema  suhcohcerens, 

"  In  a  smaller  number  of  DiatomefB,  species  of  the  genera  so  nearly  allied 
together,  Epithemia,  Ci/mbeUa,  and  Amj^hora,  the  conjugation  is  immediately 
preceded  by  a  division  of  the  mother-cells  into  two,  analogous  to  the  division 
of  the  ceUs  of  CJosterium  rostmtum  when  about  to  conjugate.  This  division 
is  longitudinal,  taking  place  exactly  as  in  the  vegetative  division  in  Cymhella 
Pedicidus,  Ampliora  ovalis,  arid  Epithemia  Sore.v,  but  transverse  and  in  a 
direction  crossing  that  of  the  vegetative  division  in  Epithemia  turyida,  E.  gihha, 
and  E.  verrucosa. 

"  Eecent  obsei^ations  show  distinctly  that  the  conjugation  of  the  Diatomese 
agrees  in  all  essential  points  with  that  of  the  Desmidieae.  ^yhen  a  cell  is 
about  to  conjugate,  there  is  produced  in  it  a  coat  round  the  entire  contents, 
accm-ately  liiiing  the  old  membrane,  but  not  adhering  to  it.  .  The  growth  of 
this  coat  cracks  the  old  cell-membrane  exactly  in  the  same  way  as  occurs  in 
vegetative  division.  From  the  fissure  the  young,  smooth  coat  emerges,  in  the 
form  of  a  vesicle,  and  unites  with  the  similar  structiu"e  produced  by  a  neigh- 
boiuing  cell.  Al.  Braun  thought  it  must  be  assumed,  from  Thwaites's  obser- 
vations, that  the  primordial  utricles  of  the  two  conjugating  Diatomean  cells 
imited ;  but  that  this  is  not  the  case,  and  that  a  soft  and  flexible  cell-mem- 
brane, protnided  from  the  cracked,  rigid,  old  shell,  encloses  the  contents 
destined  to  be  blended  with  those  of  the  neighbouiing  cell,  is  distinctly  shown 
by  Smith's  figure  of  Rhahdonema  arcuatum,  and  Carter's  of  Cocconeis  Pedi- 
cidus and  Amphora  ovalis.  The  introductory  part  of  the  conjugation  is  dis- 
tinguished in  no  respect  from  the  vegetative  cell-division  in  Epithemia  Sorecc, 
Amphora  ovalis  and  Cymhella  Pediculus,  and,  further,  in  CJosterium  rostratum  ; 
in  Epithemia  turgida,  gihha,  and  verrucosa,  only  by  a  different  position  of  the 
wall  dividing  the  mother-cell ;  in  the  rest  of  the  Diatomese  and  Desmidieae,  by 
omission  of  the  formation  of  septa, — frequently,  also,  by  one-sided  dehiscence 
of  the  cracked  mother-cell,  whose  shells  remain  still  connected  at  one  side. 

"  Thwaites's  observations  estabhshed  that  the  ceU  produced  from  the  conju- 
gation of  two  cells  of  a  Diatomacean,  very  soon  after  its  origin,  assumed  the 
form  of  the  mother- cell,  becoming  distinguishable  from  it  almost  solely  by 
being  twice  as  large.  Smith  has  endeavoured  to  render  it  probable  that  the 
colonies  of  young  individuals,  enclosed  in  a  cyst,  of  Coccoyieis  Cistida,  Gom^ 
phonemci  dichotomum,  and  Synedra  radians,  some  of  which  he  found  associated 
with  conjugated,  fiill-grown  individuals,  must  have  originated  from  the  divi- 
sion of  the  spores  (sporanges  of  Enghsh  authors).  This  hypothesis  has  much 
in  its  favoiu%  but,  in  the  present  condition  of  our  knowledge,  it  is  inexplicable 
where  the  sihcious  shells  of  the  spore-cells  remain.  However  this  may  be, 
there  is  no  doubt  of  the  occurrence  of  cysts  of  this  kind.  In  the  same  pools 
of  a  marshy  meadow  which  repeatedly  furnished  me  with  conjugated  indivi- 
duals of  Cyclotella  late  in  autumn,  I  found,  in  early  spring  of  two  successive 
years,  globular  cells,  each  of  which  enclosed  a  great  number  (32  to  40)  of 
small  individuals  of  the  same  species.  The  walls  of  these  cells  appeared 
shai^ply  defined  internally  and  externally  ;  the  contents  of  a  thin,  fluid  nature. 


66  GENERAL  HISTORY  OF  THE  INFIJSOEIA. 

Structures  similar  to  those  represented  by  Smith,  of  Synedra  radians,  oecui-red 
in  extreme  abundance  in  the  end  of  the  autumn  of  1854,  in  company  with 
Synedra  Ulna,  Here  the  cells,  which,  like  those  observed  by  Smith  in  the 
allied  species,  had  a  diseased  aspect  and  an  abnormal  arrangement  of  the 
coloured  contents,  were  imbedded  in  a  granular  jelly,  of  a  reddish  colour  by 
transmitted  light.  I  very  much  doubt  whether  these  last  were  in  a  condition 
capable  of  further  development ;  while  in  reference  to  the  cysts  of  CydoteUa 
ojyerctdata,  I  share  Smith's  opinion. 

"  The  estabhshment  of  the  assertion  that  the  commencement  of  conjugation 
in  the  Desmidieae  and  Diatomeae  is  but  little  distinguished  from  the  com- 
mencement of  vegetative  cell-division,  renders  some  discussion  of  the  latter 
requisite.  Pringsheim  has  already  dii^ected  attention  to  the  resemblance  of 
this  process  in  the  Desmidieae  to  the  vegetative  cell-multiplication  of  the 
joints  of  (Edogonium.  In  fact,  it  is  an  absolutely  general  phenomenon  in  the 
true  Desmidieae,  so  far  as  observation  reaches,  that  the  older  parts  of  the 
membrane  of  a  cell  about  to  divide,  do  not,  as  in  other  cases  (for  example, 
in  Zygnemeae),  regularly  increase  in  size  with  the  parent-cell  by  growth  in 
all  directions  ;  but  the  older,  outer  layers  of  the  integument  spht  open  with 
an  annular  crack  at  the  equator  of  the  cell,  shortly  after  (or  during  ?)  the 
division.  They  still  remain  sticking  on,  covering  the  ends  of  the  cell  with  a 
thick  envelope,  but  become  removed  gradually  fiu'ther  apart  by  the  interpo- 
sition of  new  cellulose  between  their  fractured  edges.  The  interposed  new 
coat  is  the  dii'ect  continuation  of  that  which  hues  the  internal  surface  of  the 
cracked  halves  of  the  old  shell.  It  is  the  margins  of  the  half-sheUs  which 
constitute  the  rings,  parallel  to  the  end-surfaces,  upon  the  cyhndrical  lateral 
surfaces  of  the  cells  of  Hyahtheca  dissdiens  and  H.  mucosa,  the  wrinkled  pro- 
jections of  the  membrane  in  the  middle  of  the  deep  constriction  of  the  cell  of 
Micrasterias  and  the  large  Euastra,  of  the  flat  constriction  of  the  cell  of 
Docid'mm,  as  also  the  ring  at  the  equator  of  the  external  surface  of  Closte- 
rium :  in  CJosterium  and  in  Docidmm,  frequently  as  many  as  six  may  be 
counted, — a  phenomenon  which,  in  Docidium  truncatum  and  the  large  Clos- 
teria,  may  be  recognized  at  fii^st  sight  as  dependent  upon  a  number  of  halves 
of  cracked  cells  regularly  encasing  their  successors. 

"  The  dehiscence  of  the  coat  of  the  dividing  cell  is,  in  all  obsei^ved  cases, 
preceded  by  the  formation  of  the  septum  dividing  the  cell  into  two  halves 
\Cosmar'mm  margaritiferum).  The  gradual  development  of  this  from  the 
margin  of  the  cell- wall  inwards,  as  a  gradually- widening  annular  fold  of  the 
innermost  layer  of  the  integument,  has  not  yet  been  observed,  and,  from 
analogy  with  the  processes  in  (Edogonium,  is  scarcely  probable.  But,  as  in 
(Edogonium,  the  contents  of  the  cell  may  be  contracted,  before  the  fonnation 
of  the  septum,  into  two  masses,  in  contact,  but  separated  by  a  sharp  hne 
of  demarcation  (two  contracted  daughter- cells  imperfectly  cut  off  from  one 
another,  still  adhering  together  at  the  place  of  constriction). 

"  From  the  half-shells  of  cells  of  the  same  Docidium  which  dehisced  under 
the  eye  of  the  observer,  emerged,  within  half-an-hom%  to  the  extent  of  4th  or 
^th  of  the  length  of  the  half- shells,  the  daughter- cells,  still  intimately  con- 
nected at  the  point  of  contact.  They  could  henceforth  be  perceived  to  be 
enclosed  by  a  cellulose  coat,  fii^m  although  dehcate.  Treated  with  reagents 
strongly  extracting  water,  such  as  glycerine,  one  or  both  of  the  extruded 
pieces  frequently  di-ew  back  into  the  halves  of  the  shells  of  the  mother- cell, 
the  projecting  pieces  of  membrane  becoming  doubled  inwards.  The  just- 
emerged  coats  of  the  daughter- cells  of  Docidium  did  not  take  a  blue  colour 
when  treated  with  iodized  chloride  of  zinc,  while  the  old  halves  of  the  mem- 
brane of  the  divided  cell  assumed  the  blue  colour  immediately. 


OF  THE  DIATOME.E.  67 

"  In  Cosmarium  margaritifermn  and  Staurastrum  dejectum,  it  may  be  easily 
obseiTed  that  a  slight  elongation  of  the  isthmus,  and  the  fonnation  of  a  septum 
passing  across  the  middle  of  this,  precede  the  aj^pearanee  of  new  half-cells 
in  the  deep  constriction.  It  is  after  the  appearance  of  the  septum  that  the 
old  waU  of  the  mother- cell  breaks  by  an  annular  fissure  exactly  at  the  place 
where  that  septum  is  formed.  The  two  halves  of  the  old  cell-coat  are  then 
separated  by  the  bulging- out  of  the  younger,  inner  layers  of  membrane,  not 
fii^mly  adherent  to  the  old  portions.  The  new  halves  are  at  first  lined  only 
by  protnided  portions  of  the  peUicle  of  theii'  contents  (outermost  layer  of 
the  parietal  coats  of  protoplasm)  belonging  to  the  older  half-ceUs  ;  from  the 
moment  only  of  the  dehiscence  of  the  old  cell- coat,  does  a  portion  of  the 
granular  contents  of  the  older  cell-halves  make  its  way  into  the  new  emerging 
halves. 

"  In  like  manner,  doubtless,  occurs  the  cell- division  of  Micrasterias,  of  the 
large  foiTas  of  Euastrum,  Cosmarium,  Staurastrum,  and  other  Desmidieae, 
only  that  they  have  not  been  observed  completely,  because  these  larger  Des- 
midieae  very  seldom  multiply  by  division  out  of  their  natural  stations.  The 
ceU-di\dsion  of  the  Diatomeae  that  have  hitherto  been  observed  in  vegetative 
multipKcation,  differs  in  essential  points  from  that  just  described. 

''  When  a  cell  of  Navicula  {Pimiularia)  viridis  is  about  to  divide,  there 
appears  upon  one  of  the  secondary  sides  (front  view  of  English  authors), 
parallel  to  the  primaiy  sides  (the  furrowed  faces  of  the  cell  having  an  elon- 
gated elliptical  outline),  an  annular  rim,  which,  growing  gradually  inwards, 
constricts  the  contents  of  the  cell  by  an  annular  fiuTow,  in  a  manner  exactly 
similar  to  that  of  the  commencement  of  cross -division  in  a  cell  of  CJadopliora. 
AMien  a  cell  in  this  state  is  treated  with  substances  producing  slight  endos- 
mosis  (for  instance,  a  weak  solution  of  carbonate  of  ammonia),  the  contents 
retract  on  both  sides  from  the  annular  rim,  and  constitute  two  completely 
separate  cell-Hke  stnictiuTS  (halves  of  a  primordial  utricle),  each  of  a  very 
long  ellipsoidal  form,  and  each  lying  close  agaiust  one  of  the  primaiy  sides 
{faces  of  halves)  of  the  cell.  I^Tien  the  annular  rim  has  grown  inwards  to 
about  the  sixth  part  of  the  shortest  diameter  of  the  cell,  its  development  is 
arrested.  In  natural  conditions,  this  stage  is  succeeded  by  the  retraction  of 
the  primordial  utricle  from  it.  Each  of  these  halves  of  the  cell-contents 
becomes  clothed,  on  the  side  turned  away  from  the  primary  side  of  the  cell, 
with  a  new  membrane,  which  soon  exhibits  the  fii\st  indications  of  the  pecu- 
liar thickening  ribs  and  nodules  of  one  of  the  primaiy  sides  of  our  Pinnularia. 
The  cell  has  now  completed  its  division.  Seen  from  one  of  the  secondary 
sides,  it  contains  two  new  individuals,  equal  to  the  mother-cell  in  length  and 
breadth,  but  only  possessing  one-third  of  its  thickness.  The  externaUy- 
situated  primaiy  side  of  each  of  them  is  the  old  piimaiy  side  of  the  mother- 
cell,  to  which  we  must  imagine  the  newly-formed  membrane  of  the  daughter- 
cell  closely  adherent  at  all  points.  Perhaps  the  narrow  secondary  sides  of 
the  new  cells  may  be  in  the  same  condition.  But  the  contiguous  primary 
sides  of  the  daughter- cells  are  totally  new  structures,  which,  developed  rapidly, 
in  a  short  time  become  similar  to  the  old  primaiy  sides  in  every  part.  The 
two  daughter- cells  are  at  first  held  together  by  the  broad  middle  piece  of  the 
secondary  sides  of  the  mother- cell,  bearing  the  above-mentioned  annular  rim 
inside.  The  contents  of  the  intermediate  space  consist  of  a  transparent  fluid 
destitute  of  any  solid  structures,  doubtless  pure  water.  The  two  daughter- 
cells  are  finally  set  free  by  the  gradual  '  weathering  '  of  the  zone-membrane 
which  holds  them  together.  The  division  of  Surirella  hifrons  takes  place 
exactly  in  the  same  way.  An  essentially  similar  kind  of  vegetative  multipli- 
cation is  widely  diffused,  if  not  general,  in  the  Diatomese.     The  well-known 

f2 


68  GENERAL  niSTORY  OF  THE  INFUSORIA. 

phenomenon  of  the  formation  of  a  tubular  membrane,  often  impregnated  with 
silex,  and  elegantly  dotted  or  areolated,  connecting  the  two  segments  of 
Isthmia,  Melosira,  &c.,  depends  upon  the  same  process. 

"  An  analogous  case  is  met  with  in  the  formation  of  the  spores  of  Pellia 
epipliylla.  The  mother- cell  here  produces  six  ridges  of  cellulose  projecting 
inward  from  the  internal  wall,  intersecting  at  an  angle  of  60° ;  these  ridges 
grow  in  toward  the  middle  point  of  the  cell,  like  the  annular  ridge  of  Cla- 
dojpJiora  at  the  commencement  of  cell-division.  A\Tien  these  projecting  ridges 
have  attained  the  breadth  of  a  fourth  part  of  the  transverse  cHameter  of  the 
mother- cell,  the  cell- contents  divide  into  four  parts,  which,  retracting  from 
one  another  and  from  those  ridges,  occupy  the  four  chambers  of  the  cell,  each 
of  which  is  vaulted  externally  and  bounded  laterally  by  three  of  the  ridges, — 
here  becoming  coated  with  a  membrane  and  developed  into  a  spore,  while  the 
tetrahedi'al  space  in  the  middle  of  the  cell,  bounded  by  the  six  ridges,  remains 
filled  only  with  watery  fluid.  The  spores  become  free  by  the  solution  of  the 
enveloping  part  of  the  membrane  of  the  mother- cell.  The  resemblance  of 
this  process  to  the  vegetative  multiplication  of  Navicula  consists  in  the  inter- 
ruption of  the  division  of  the  cell  by  the  formation  of  septa,  and  the  subse- 
quent completion  of  the  daughter- cells  by  secretion  of  membrane  on  the 
external  surface  of  contracted  portions  of  the  contents  of  the  mother- cell. 
A  deviation  occurs  in  the  circumstance  that  in  Pellia  the  segment  of  the  coat 
of  the  mother- cell  which  is  in  contact  with  the  external  smface  of  the  daughter- 
cell  becomes  dissolved,  while  in  Navicula  it  persists  and  remains  most  inti- 
mately connected  with  the  daughter- cell. 

"  The  newly-formed  parts  of  the  cell-coat  facing  together  in  the  division 
are,  in  the  Diatomeae,  and  still  more  clearly  in  the  Desmidiea),  perfectly  smooth 
and  even  for  some  time  after  theii'  production  ;  it  is  subsequently  that  they 
obtain  the  often  veiy  considerable  tubercles  and  spines,  consisting  principally 
of  cellulose.  The  same  applies  to  the  processes  upon  the  outer  integument  of  the 
spores  of  Euastra,  Cosmaria  and  Staurastra  produced  in  the  conjugation.  These 
phenomena,  as  also  the  autumnal  secretion  of  jelly  by  many  of  the  Desmidiese, 
deserve  more  notice  than  they  have  hitherto  attracted  in  connexion  with  the 
theory  of  the  life  of  the  vegetable  cell.  Still  more  remarkable  behaviour  is 
displayed  by  the  cell-coat  of  an  organism  which  I  refer  only  doubtfully  to 
the  DesmidieEe.  In  many  pools  about  Leipsic,  in  which  Desmidiese  abounded, 
occuiTcd  large,  accurately  si^herical,  tliick- walled  cells,  some  as  much  as  -05 
miUim.  in  diameter,  rich  in  chlorophyll,  which  not  only  lined  the  internal  wall 
as  a  connected  granular  layer,  but — as  in  many  Desmidieae — formed  groups, 
distributed,  in  the  interior  of  the  cell,  in  a  system  of  radially-arranged  plates, 
which  presented  a  stellate  appearance  when  seen  from  the  side.  It  would 
be  no  great  stretch  of  imagination  to  regard  these  cells  as  the  conjugation- 
spores  of  a  large  Desmidiean.  But  these  spores  are  all  spiny,  with  the  single 
exception  of  those  of  Xanthidium  armatum.  This  very  striking  form  occurs 
but  rarely  with  us,  having  hitherto  been  found  only  in  a  single  locahty,  while 
these  globules  are  as  common  as  they  are  abundant,  and  are  often  found  in 
great  numbers  in  forest  pools,  wliich  harbour,  in  addition  to  them,  only  very 
small  Desmidieae.  But  such  a  supposition  is  still  more  decidedly  negatived 
by  the  circumstance  that  the  cells  in  question  are  sometimes  found  dividing 
into  two.  This  renders  it  in  the  highest  degree  probable  that  they  are  inde- 
pendent organisms — Desmidieae  without  a  central  constriction,  which  may 
form  the  commencement  of  a  series  of  forms  terminating  in  Micrasterias. 

"  These  cells  frequently  appear  surrounded  by  a  wider  coat,  inside  which  the 
cell  then  floats  freely,  enclosed  by  its  own  closely-investing  coat.  Several 
such  empty  coats  are  often  met  'vvith,  even  as  many  as  six  sticking  one  inside 


I 


OF  THE  DIATOilEJE.  bM 

another.  Close  investigation  shows  that  the  broader  empty  coats  have  an 
orifice,  towards  the  border  of  which  the  membrane  grows  gradually  thinner. 
These  holes  have  not  the  aspect  of  perforations  of  the  outer  walls  through 
external  injiuy ;  they  rather  resemble  the  orifices  of  the  walls  of  CJadoj^hora, 
thi'ough  which  the  swarming-spores  escape.  It  might  be  conjectured  that 
the  plant  multiplied  by  swarming-spores,  and  that  solitaiy  ones  becoming 
developed  inside  the  empty  coat  of  the  mother- cell  gave  rise  to  that  appear- 
ance ;  but  this  is  contradicted  by  the  great  frequency  of  their  occurrence, 
as  also  by  the  circumstance  that  we  never  find  a  number  of  green  cells  inside 
one  cell- coat.  It  is  more  probable  that  the  contents  of  the  cell  contract,  and 
become  coated  with  a  new  membrane,  when  the  old  one  is  perforated, — by 
unknown  causes,  which  perhaps  lie  in  the  course  of  development  of  the 
species. 

"  If  we  seek  to  bring  the  phenomena  introductory  to  vegetative  cell-mul- 
tiplication under  one  point  of  view  mth  the  preparations  for  conjugation,  we 
find  that,  in  the  Desmicheae,  in  both  cases  a  new  membrane  is  formed  aroimd 
the  total  contents  of  the  ceU,  wliich  indeed  lies  close  upon  the  old  coat  at  all 
points,  but  by  no  means  adheres  to  it,  as  we  are  accustomed  to  conceive  of 
the  so-called  layers  of  thickening  of  the  cell-wall.  The  growth  of  the  young 
membrane  cracks  the  stronger  old  one — in  vegetative  cell-multiplication 
always  in  an  annular  fonn,  in  conjugation,  mostly  in  a  one-sided  manner, 
with  a  valve-hke  slit  (Hi/ahtheca  dissiliens ;  Closterhim).  At  this  stage 
first  occurs  a  distinction  between  the  two  processes  of  development, — the 
foimation  of  a  sej)tLun  taking  place  in  cell-division,  while  in  conjugation  the 
protniding  part  of  the  young  membrane  continues  to  enlarge  outwards, 
without,  in  many  cases,  any  separation  of  the  contents  into  two  halves  taldng 
place.  The  younger,  innermost  layer  of  membrane  remains  with  that  portion 
lining  the  old  cell-coat,  sticking  wholly  in  this  in  Hyalotheea,  Bambimna, 
Cosmarium.  But  even  in  individuals  of  species  of  the  last  genus  it  sometimes 
occurs,  in  Tetmemorus  and  Closterium  (e.  g.  C.  acutum)  as  a  rule  (although  by 
no  means  without  exception),  that  the  ends  of  the  connected  inner  coats  of 
the  conjugating  cells  draw  themselves  out  of  the  cast-off"  shells  of  the  mother- 
ceUs,  in  extreme  cases  entirely ;  so  that  the  cell  originating  by  the  blending 
of  the  internal  coats  of  two  individuals  (inside  which  the  spore  is  fonned) 
becomes  capable  of  being  rounded  off"  into  a  sphere. 

"  Both  the  ceU- division  and  the  preparation  for  conjugation  of  Zygnemese 
are  distinguished  from  the  processes  in  Desmidiea?  by  the  circumstance  that 
in  the  former  the  wall  of  the  oldest  cells  grows  in  its  entire  mass,  and  does 
not  allow  the  younger  layers  of  membrane  to  protnide  through  fissures  or 
slits. 

"  In  the  Diatomece,  lastly,  the  division  into  two,  like  the  conjugation,  takes 
place,  seemingly,  in  all  cases,  through  and  after  a  preparatory  contraction  of 
the  contents  or  separate  portions  of  the  contents  of  the  cells  ;  and  in  not  a 
few  cases  the  conjugation  takes  place  during,  and  is  accompanied  by,  di\-ision 
of  the  contracted  contents  into  two  portions.  A\Tiat  import  for  the  life  of  the 
species  has  the  conjugation  of  the  Zygnemeae,  Desmidieae,  Palmelle£e  (Pal- 
mofjloea),  and  Desmidie^  ?  Our  knowledge  of  the  race  of  Algae,  so  import- 
antly advanced  by  the  labours  of  Pringsheim  and  Cohn,  should  allow  a  more 
positive  answer  to  this  question  than  that  inquirer,  to  whom  the  study  owes 
most  brilliant  acquisitions,  is  inclined  to  give.  The  idea  of  sexuality  of  the 
lower  Algae  depends  principally  upon  the  perfectly  justifiable,  but  still  only 
analogical  conclusions  which,  starting  from  the  observations  made  diuing  a 
centurj^  on  the  Phanerogamia,  have  advanced,  through  the  intermediation  of 
those,  less  numerous,  on  the  Vascular  Ci-jiitogamia  and  Muscineae,  and  the 


70  GENEEAL  HISTOEY  OF  THE  INFUSOEIA. 

facts  established  in  Fitcus  by  experiment  of  artificial  separation  or  union  of 

the  sexes,  to  the  (Edogoma,  Vaucheria,  Sjphceroplea  and  Volvox.  Pringsheim's 
declaration,  that  physiological  questions  of  such  a  kind  as  the  necessity  of  the 
action  of  the  fecundating  matter  in  generation  can  only  be  certainly  decided 
by  the  observation  of  morphological  processes,  will  not  be  adopted.  Expe- 
riment has  long  ago  proved  the  existence  of  sexes  in  the  Phanerogamia, 
before  the  penetration  of  the  pollen-tube  into  the  ovule,  and  its  relation  to 
the  germinal  vesicle,  had  been  made  out, — obseiTations  which  that  theory 
really  no  longer  required  for  the  establishment  of  its  main  question.  And 
if,  among  so  many  confirmatory  experiments,  a  few  negative  results  present 
themselves,  in  what  branch  of  human  knowledge  do  we  not  meet  with  similar 
phenomena  ?     The  general  niles  of  evidence  hold  good  in  such  cases. 

"  The  same  analogies,  then,  which  lead  ils  to  recognize  a  fecundation  in 
the  penetration  of  the  spermatic  body  of  (Edogonium  into  the  mother- cell  of 
the  spore,  in  the  mixtm^e  of  that  body  with  the  contracted  contents  of  the 
mother-cell  of  the  spore  (with  Pringsheim's  '  fecundation-globule '),  must 
necessarily  lead  us  to  regard  conjugation  as  a  fecundation.  It  is  distinguished 
from  the  process  in  (Edogonium  only  by  the  fact  that  the  portions  of  cell- 
contents  which  become  blended  into  one  cell  are  of  equal  size,  and  that  there 
is  not  one  of  them  provided  with  apparatus  by  means  of  which,  like  the 
spermatic  body  of  (Edogonium  by  its  cilia,  it  is  moved  onward  until  it  reaches 
the  cell  to  be  fecundated, — both  points,  evidently,  of  no  essential  importance. 
"  The  sporangial  frustules  difi'er  in  general  from  the  parent  forms  not  merely 
in  size,  but  also  in  the  number  of  striae  or  of  other  markings,  and  to  some 
slight  degree  in  outline.  Such  variation,  M.  Thuret  contends,  proves  the  phe- 
nomenon of  conjugation  to  be,  not  a  true  mode  of  reproduction,  but  only  '  a 
second  mode  of  multiplication  of  frustules,  very  curious  and  very  abnormal.' 

*'  In  the  immature  condition,  we  are  infoiTaed  by  Mr.  Thwaites,  it  happens 
that  the  sporangia  in  many  species  resemble  in  general  characters  the  mature 
frustules  of  another  species  or  even  of  an  allied  genus.  Thus  the  sporangia 
of  Gomj)lionema  mimttissimum  (XI.  17)  and  of  G.  dichotomum  have  a  close 
resemblance  to  the  frustules  of  Cocconema.  On  the  other  hand,  in  some  genera, 
as  in  Cocconema,  the  sporangia  take  on  at  once  the  exact  characters  of  the 
ordinary  frustules,  from  which  they  differ  only  in  their  exceeding  that  of  the 
majority  of  the  latter  in  dimensions. 

^' When  a  sporangium  in  a  transitional  condition  is  like  the  frustule  of  another 
genus,  we  are  assisted  in  distinguishing  its  true  natiure  and  affinity,  oftentimes, 
by  the"  persistence  of  the  mucus  diffused  around  it ;  or  by  continued  observa- 
tion we  may  witness  its  assumption  ultimately  of  its  true  specific  characters, 
including  the  development  of  its  pedicle  or  stalk,  where  the  possession  of 
such  an  organ  is  a  characteristic  (as  in  Gomjyhonema).^' 

The  above  fact  suggests  it  as  very  probable  that  transitional  forms  have 
been  described  as  particular  species,  or  located  in  wrong  genera.  Thus  Mr. 
Thwaites  thinks  that  Xiitzing's  Epithemia  vertagus  is  no  other  than  the 
sporangium  of  Eunotia  turgid  a,  and  also  that  the  enlarged  frustules  of  the 
Melosirece,  which  that  same  writer  had  conjectiu-ally  regarded  as  reproductive 
bodies,  are  in.  fact  the  sporangial  product  of  conjugation,  and  give  rise  to 
a  chain  of  frustules  larger  than  those  from  which  they  had  themselves 
originated. 

The  subsequent  history  of'  the  sporangial  frustules  on  being  matured  is 
not  satisfactorily  made  out.  Prof.  Smith  has  the  following  on  the  question 
(J".  M.  S.  1855,  p.  131)  : — "  The  ordinary  Diatomaceous  fmstule  seems  to  owe 
its  production  to  the  protoplasmic  contents  of  the  sporangial  frustule  formed 
by  the  process  of  conjugation.     These  sporangia,  like  the  seeds  of  higher 


OF  THE  DlAT031EiE.  71 

plants,  often  remain  for  a  long  period  dormant,  and  are  borne  about  by  cur- 
rents or  become  imbedded  in  the  mud  of  the  waters  in  which  they  have  been 
produced,  until  the  circimistances  necessary  to  their  development  concur  to 
call  them  into  activity.  At  such  times  theii'  sihcious  epiderms  open  to  per- 
mit the  escape  of  the  contained  endochrome,  which  is  resolved  into  a  myriad 
of  embryonic  fnistules  ;  these  either  remain  free  or  surround  themselves  Tvdth 
mucus,  fonning  a  pellicle  or  stratum,  and  in  a  definite  but  unascertained 
period  reach  the  mature  form  of  the  ordinary  frustule,"  when  their  fiu'ther 
growth  appears  almost  entii^ely  arrested  by  the  production  of  the  sihcious 
coat,  and  when  multiphcation  by  self-division  provides  for  the  continuation  of 
individual  life.  To  continue  the  quotation,  ''  The  size  of  the  mature  frustule 
before  self- division  commences  is,  however,  dependent  upon  the  idiosjTicrasy 
of  the  embryo,  or  upon  the  cii'cumstances  in  which  its  embryonic  growth  takes 
place  ;  consequently  a  very  conspicuous  diversity  in  their  relative  magnitudes 
may  be  usually  noticed  in  any  large  aggregation  of  individuals,  or  in  the  same 
species  collected  in  different  locahties." 

The  behef  that  the  contents  of  the  sporangial  frustules  resolve  themselves 
into  a  '  brood'  of  Diatoms,  having  the  same  form  and  specific  characters  as 
the  original  parent-cells.  Prof.  Smith  establishes  by  the  following  observations 
made  by  himself  (Si/no2:)sis,  vol.  ii.  p.  xv)  : — "  In  the  gathering  of  Cocconenia 
Cistula  made  in  April  1852,  which  contained  numerous  instances  of  the  con- 
jugating process,  I  observed  the  frequent  occiuTence  of  cysts  enclosing  minute 
bodies  variable  in  their  number  and  size,  and  many  of  which  had  the  outhne 
and  markings  of  the  siUTounding  forms  and  were  obviously  young  frustules  of 
the  Cocconema.  It  would  appear  that  the  production  of  the  young  frustules 
is  preceded  by  the  separation  and  throwing  off  of  the  sihcious  valves  of  the 
sporangium  and  the  constriction  or  enlargement  of  its  primordial  utricle, 
according  to  the  number  of  young  frustules  originating  in  its  protoplasmic 
contents.  In  this  gathering,  forms  of  eveiy  size,  intermediate  between  the 
minutest  fiiistule  in  the  cyst  and  the  ordinary  frustules  engaged  in  the 
conjugating  process,  were  easily  to  be  detected ;  and  the  conclusion  was 
inevitable,  that  the  cysts  and  their  contents  were  sporangia  of  the  species 
with  which  they  were  associated,  and  indicated  the  several  stages  of  the 
reproductive  process." 

Again,  in  a  gathering  of  Synedra  radians,  although  not  found  at  the 
time  in  a  congregating  state,  yet  the  appearance  of  the  cysts  and  of  their 
contents  was  equally  characteristic  of  the  reproductive  process.  That  such 
a  "  cystoid  condition  is  one  stage  in  the  normal  development  of  its  reproduc- 
tion," a  subsequent  examination  in  a  distant  locahty  satisfied  him. 

The  prosecution  of  this  inquiiy  into  the  final  changes  of  the  sporangial 
fnistules  is  seriously  impeded  by  the  dissolution  of  the  investing  mucus  and 
the  consequent  dispersion  of  the  reproductive  bodies. 

Thirty-two  species  of  the  Diatomeae  have  been  observed  in  the  act  of  con- 
jugation, belonging  to  the  genera  Epitliemia,  Cocconeis,  Cocconema,  CymbeUa, 
Cyclotella,  GompTionema,  Himantidium,  Achnantlies,  Rhahdonema,  Melosira, 
Navicida,  Surirella,  Amphora,  Orthosira,  Encyonema,  Colletonema,  and  Schizo- 
nema.  On  this  paucity  compared  with  the  number  of  known  genera.  Prof. 
Smith  has  the  following  explanatory  remarks  {Synops.  ii.  p.  xi) : — "One  reason 
for  the  paucity  of  observations  on  this  process  in  the  Diatomeae  is  no  doubt  to 
be  foimd  in  the  changes  which  usually  take  place  in  the  condition  of  these 
organisms  at  this  period  of  their  existence.  During  conjugation  the  progress 
of  self-division  is  arrested,  the  general  mucous  envelope  or  stratum  produced 
during  seK-division  is  dissolved,  and  the  conjugating  pairs  of  frustules  become 
detached  from  the  original  mass ;  they  are  thus  more  readily  borne  away  and 


.72  GENEKAL  HISTOEY  OF  THE  INFUSOBIA. 

dispersed  by  the  surroimding  currents  or  the  movements  of  worms  and  in- 
sects, and  their  detection  becomes  in  consequence  more  casual  and  difficult. 
By  far  the  greater  number  of  the  species  I  have  mentioned  belong  to  those 
genera  whose  frustules  are  adherent,  or  attached  by  stipes  to  foreign  bodies, 
or  which  form  continuous  filaments  or  aggregated  frondose  expansions.  ISTot 
more  than  four,  viz.  CycloteUa  Kutzingiana,  Navicula  firma,  Amphora  ovalis, 
and  Cymhella  Pediculus,  are  to  be  regarded  as  free  forms :  the  reason  I  have 
just  given  will  account  for  this  cii'cumstance  ;  and  the  larger  proportion  of 
adherent  or  frondose  species  detected  in  conjugation  may  doubtless  be  ascribed 
to  the  firmer  position  conferred  upon  such  forms  by  the  presence  of  these 
accessory  methods  of  attachment  and  adhesion,  while  the  filamentous  species, 
being  usually  aggregated  in  considerable  masses  or  entangled  amidst  the 
branches  of  the  larger  Algae,  are  also  less  liable  to  dispersion." 

Another  mode  of  development,  first  pointed  out  by  Mr.  Ralfs  in  his  early 
contributions  to  the  history  of  the  Diatomese  {A.  N.  H.  1843),  by  an  internal 
gemmation  or  production  of  cells  approaching  in  physiological  features  to 
self- division,  appears  to  prevail  in  at  least  some  instances.  It  is  alluded  to  by 
Prof.  Smith,  when  speaking  of  the  Meridion  circidare  {op.  cit.  7).  He  met  with 
a  variety  of  frustules,  which  upon  a  close  examination,  especially  in  a  li\'ing 
state,  led  him  to  the  conviction  ''  that  the  appearance  of  a  double  wall  of  silex 
is  owing  to  the  formation  ^\4thin  the  original  frustule  of  a  second  perfect  cell, 
instead  of  the  usual  mode  of  division  by  which  the  original  fnistule  is  divided 
into  two  half-new  cells ....  In  the  present  case,  the  central  vescicle  or  cyto- 
blast  becomes  enlarged  without  division,  and  secretes  on  its  extension  two 
new  valves,  which  are  pushed  outwards  until  they  lie  in  close  apj)roximation 
with  the  original  valves.  This  process  is  not  always  repeated  ;  the  usual  mode 
of  seK-division  again  recul^s,  and  two  valves  are  formed  in  the  interior  of 
this  new  cell  according  to  the  nonnal  method.  .  .  .This  unusual  method  of 
development  is  not,  however,  sufficiently  constant  to  warrant  the  separation 
of  such  frastules  from  the  species  in  which  it  occm^s,  perhaps  hardly  sufficient 
to  constitute  a  variety,  as  frustules  in  both  the  ordinary'  and  abnormal  states 
may  be  met  with  in  the  same  gathering  and  even  in  the  same  filament." 

Himantidimn  Soleirolii  is  another  species  producing  internal  cells,  which 
Prof.  Smith  quoted,  remarkmg  that  he  had  no  doubt  it  is  merely  an  accidental 
modification  of  cell-growth,  since,  in  the  same  filament,  cells  thus  formed  may 
be  frequently  found  along  -vsdth  others  following  the  normal  mode  of  self- divi- 
sion. In  Odontidium  anomalum,  this  variety  is  in  fact  the  usual  condition 
of  the  frustules,  and  the  ordinary  mode  of  self-di\dsion  is  but  rarely  to  be 
met  with.  A  remarkable  instance  of  this  abnormal  development  presented 
itself  to  Prof.  Smith  in  Achnanthes  subsessiUs,  in  which  '-'  the  formation  of  a 
cell  interior  to  the  original  one  had  proceeded  through  several  successive 
stages,  and  the  result  is  a  compound  fnistule,  consisting  of  the  mother-ceU 
and  a  number  of  included  cells,  each  successive  development  being  embraced 
by  the  others  pre\iously  formed." 

Mr.  Ealfs  has  recently  {J.  M.  S.  1857,  p.  14)  recurred  to  the  subject  of  this 
plan  of  reproduction,  and  has  found  himself  obHged  to  differ  from  Prof.  Smith 
in  some  particulars.  He  writes  :  "  Although  it  is  true  that  '  we  frequently 
find  in  the  same  filament  cells  thus  formed,  and  others  following  the  normal 
mode  of  growth,'  as  I  foimerly  showed,  yet  I  cannot  agree  to  Prof.  Smith's 
statement  under  Bimantidium  Soleirolii,  that  '  there  is  no  doubt  of  its  being 
merely  an  accidental  modification  of  cell-growth.'  On  the  contrary,  I  beheve 
it  to  be  a  reproductive  state  of  the  species,  and  consequently  to  have  a  definite 
and  important  part  in  their  economy. 

''  Por  several  years  I  have  attentively  watched  the  circumstances  connected 


I 


OF  THE  DIATOME^.  73 

-^-ith  the  fonnation  of  these  inner  cells  in  HimanticUum  undaJaium,  by 
gatheiing  specimens  at  short  intei-vals.  Dming  great,  part  of  the  T\inter,  the 
filaments  increase  in  bulk,  by  repeated  division  of  the  frustules,  until  they 
form  large  masses,  filling  the  ditches ;  at  length  the  inner  cells  make  their 
appearance,  at  first  spaiingiy ;  but  as  spring  advances,  it  is  difficult,  in  many 
situations,  to  obtain  a  filament  without  them.  I  have  found  that  when  these 
become  abundant,  the  filaments  cease  to  grow,  and  the  entire  mass  soon  breaks 
up  and  disappears.  The  same  thing  happens  in  the  other  species  of  Himan- 
tidium,  and  in  Meridion. 

''  I  do  not  find  that  the  inner  cell  commences  in  the  centre  and  pushes  its 
valves  outwards,  as  stated  by  Prof.  Smith.  Were  this  the  case,  the  internal 
matter  also  would  necessarily  be  pushed  outwards  by  the  advancing  valves, 
and  thus  condensed  between  them  and  the  walls  of  the  frustule.  On  the 
contraiy,  in  the  Himcuit'idium  the  internal  matter,  before  nearly  fluid,  collects 
within  the  new  cell,  becomes  dense  and  more  granular,  and  the  new  walls  are 
formed  round  it  in  the  situation  they  are  to  occupy,  leaving  an  empty  space 
between  them  and  the  walls  of  the  frustule. 

*'  The  alteration  and  condensation  of  the  colouring  matter,  and  the  ap- 
pearance, or  at  least  great  increase  of  vesicles,  have  a  strong  resemblance  to 
what  takes  place  previous  to  the  formation  of  sporangia,  the  completion  of 
which,  as  in  this  case,  usually  preludes  the  death  and  disappearance  of  the 
mass. 

"  As  in  most  acknowledged  sporangia,  the  ceil  thus  formed  always  tends 
to  assume  an  oval  or  orbicular  form.  It,  however,  is  very  frequently,  and 
perhaps  generally,  divided  in  halves,  as  in  the  fission  of  the  frustules,  so  that 
the  oval  seems  made  up  of  two  neighboimng  frustules ;  but  this  is  not  the 
case,  as  may  readily  be  ascertained  by  noticing  the  marginal  puncta  of  the 
original  fnistule. 

"  Do  these  newly- constituted  cells  ever  continue  to  divide,  as  Prof.  Smith 
supposes  ?  I  beheve  not ;  at  least  I  have  never  seen  a  specimen  in  which 
the  semi-elliptic  portions  were  separated  by  the  interposition  of  other  valves 
resembhng  either  themselves  or  those  of  the  ordinary  fnistule.  For  my  own 
part,  I  have  been  unable  to  trace  the  species  after  the  formation  of  these  cells, 
owing  to  the  quickly  succeeding  disappearance  of  the  mass.  If,  indeed,  this 
renewed  division  does  occur,  the  resemblance  to  what  takes  place  in  the 
sporangia  of  some  species  of  Melosira  would  be  increased. 

"  Prof.  Smith,  in  his  most  interesting  and  valuable  account  of  the  '  Eepro- 
duction  in  the  Diatomacese,'  enimierates  four  modes  in  which  sporangia  are 
formed.     The  third  is  thus  defijied  : — 

"  '  The  valves  of  a  single  fnLstule  separate ;  the  contents,  set  free,  rapidly 
increase  in  bulk,  and  finally  become  condensed  into  a  single  sporangiimi.' 

"  As  far  as  regards  the  Melosira  varians,  the  only  one  in  this  group  which 
I  have  had  an  opportunity  of  noticing,  I  beheve  the  process  is  essentially  the 
same  as  in  the  examples  already  described.  The  only  difi'erence  is,  that  the 
new-formed  cell  being  inflated,  and  much  larger  than  the  original  fnistule, 
the  valves  of  the  fnistule  must  necessarily  be  either  ruptured  or  iDushed  apart 
by  the  increasing  growth  of  the  sporangium,  and  the  latter  alternative  happens. 

"  I  have  seen  no  specimen  of  Mr.  Brightwell's  Chcetoceros  Wighamii,  but 
from  his  figures  I  beheve  the  goniothecia-hke  bodies  constitute  another 
example  of  the  formation  of  internal  cells. 

"  I  have  said  that  I  consider  these  interaal  cells  sporangia,  and  essentially 
of  the  same  nature  as  the  inflated  ones  of  Melosira  varians.  At  the  same 
time  we  should  not  forget  that  Mr.  Thwaites  discovered  the  Himantidium 
pectinale  in  a  truly  conjugated  state,  and  that  it  is  contrary  to  our  experience 


/  4  GEXEEAL  HISTOEY  OF  THE  IXFrSOKIA. 

of  the  economy  of  nature  that  the  same  result  should  be  obtained  in  the  same 
species  in  two  different  ways." 

M.  Focke  has  satisfied  himself  of  the  reproduction  of  some  species  of  Navi- 
culce  (A.  iV.  H.  1855,  237)  by  a  strange  complication  of  the  phenomena  of 
^'  alternation  of  generation  "  and  conjugation.  Navicula  hifroiis,  for  example, 
forms,  he  says,  by  the  spontaneous  fission  of  its  internal  substance,  spherical 
bodies  which,  hke  gemmules,  give  rise  to  Surirella  microcora.  These  by. 
conjugation  produce  N.  sphndida,  which  gives  rise  to  iV^.  hifrons  by  the  same 
process.  This  last  act  of  gemmation  has  been  obsei^ed  by  the  author  in  all 
its  phases.  He  saw  two  specimens  of  N.  spJendida,  enveloped  in  a  sort  of 
mucosity,  open  and  evacuate  the  whole  of  their  contents,  which  serv^ed  to  form 
a  N.  hifrons.  The  production  of  the  reproductive  bodies  by  the  latter  was 
also  observed;  but  their  development  into  Surirella  microcora,  and  the  pro- 
duction of  N.  splendida  by  conjugation,  rest  solely  on  the  inductions  of  the 
author. 

These  facts  require  revision  and  confirmation,  but  they  are,  nevertheless, 
worthy  of  the  attention  of  observers,  and  appear  to  point  to  phenomena  quite 
as  singular  as  those  which  have  been  revealed  to  us  within  the  last  few  years 
by  the  study  of  the  reproduction  of  so  many  of  the  lower  animals.  They,  in 
fact,  present  in  a  manner  the  converse  of  the  phenomena  exhibited  in  the 
ordinary  alternation  of  generation,  as  several  germs  or  eggs  are  necessary  for 
the  production  of  the  last  individual  of  the  cycle. 

Kiitzing  has  sunnised  the  existence  of  another  mode  of  development,  viz. 
by  germs  or  sj^ores  prepared  from  the  gonimic  contents  of  the  fmstules.  This 
method  of  j^ropagation  was  indeed  comprehended  in  Ehrenberg' s  doctrine  that 
much  of  the  granular  contents  were  ova ;  an  hj^iDothesis  started  rather  to  bring 
the  stnicture  of  the  Diatomeae  in  accordance  ^ith  the  generally  assumed  poiy- 
gastric  organization,  than  to  explain  any  observed  j^henomena,  complicated  as 
it  also  was  with  other  suppositions  of  fecundating  male  glands  or  seminal 
vesicles  and  a  sexual  discharging  orifice. 

Eabenhorst  {S'lissw a sser- Diatom,  p.  3)  has  followed  up  Kiitzing's  suggestion, 
and  affinns  that  the  frastules  of  Diatomeae  swell  up  in  a  vesicular  manner 
and  become  filled  with  a  greater  or  less  number  of  cells,  which  at  first  have 
an  irregular  figiu-e,  but  subsequently  assume  a  regiilar  oval  shape.  This 
having  happened,  the  cells  move  in  a  current  from  right  to  left  within  the 
cavity  of  the  parent-ceU,  which  by-and-by  sphts  open  and  emits  its  progeny, 
each  of  which  has,  at  an  anterior  clear  space,  two  long  projecting  cilia.  Por  a 
very  short  time  these  germs  enjoy  a  swarming  movement,  and  afterwards,  on 
becoming  stationary,  attain  with  extreme  rapidity,  or  even  sui-pass,  the  size  of 
the  parent-cell,  which  is  itself  destroyed  in  the  act.  This  plan  of  reproduc- 
tion by  the  development  of  a  brood  of  young  organisms  ^vithin  a  parent -cell, 
or,  in  more  technical  terms,  this  formation  of  active  gonidia  (microgonidia), 
prevails  in  many  of  the  lower  ^Ugae,  and  consequently  has  no  a-priori  argu- 
ment against  it.  However,  as  Prof.  Smith  remarks,  "  Its  occurrence  in  the 
Diatomeae  cannot  be  received  as  estabhshed  without  fm^ther  observation  and 
a  more  careful  record  of  the  phenomena  attending  its  progress  "  {op.  cit. 
vol.  ii.  p.  x^ii). 

Eabenhorst  has  illustrated  this  mode  of  development  in  only  one  species  of 
Melosira,  although  he  puts  it  foi-ward  in  a  general  manner  as  if  tnie  of  aU 
the  Diatomeae.  Indeed  it  occau\s  to  us  that  it  is  not  a  special  and  otherwise 
unobseiwed  process  of  reproduction,  but  merely  that  variety  of  the  act  of  con- 
jugation described  by  Mr.  Thwaites  in  the  genus  Melosira,  in  which  a  change 
in  the  endochrome  of  a  single  frustule,  attended  by  an  increase  of  contents 
and  a  consequent  enlargement — such  as  is  intimated  in  Rabenhorst's  account — 


OF  THE  DIATOME^. 


75 


converts  it  into  a  sporangium.  Beyond  this  stage,  Mr.  Thwaites  does  not 
appear  to  have  followed  the  sporangial  fnistiile  so  generated  ;  but,  assuming 
the  correctness  of  Prof.  Smith's  hypothesis  of  the  generation  and  subsequent 
evolution  of  numerous  minute  frustules  mthin  it,  do  we  not  find  a  precisely 
analogous  phenomenon  with  that  which  Eabenhorst  represents  as  an  addi- 
tional mode  of  propagation,  or  with  what  Focke  (see  preceding  page)  describes 
as  the  formation  of  gemmules  out  of  the  internal  substance,  and  their  sub- 
sequent discharge?  The  supplementaiy  phenomenon  of  alternation  with 
change  of  specific  form,  included  in  the  statement  of  the  latter  observer,  even 
if  confirmed,  will  not  afi'ect  the  general  analogy  presumed. 

Habitats. — Appearance  in  masses,  abundance,  geographical  distribution. 
— Fossil  Diatomece. — Existence  in  the  atmosphere. — Practical  uses  and  appli- 
cations of  the  Diatomece. — The  habitats  and  the  distribution  of  the  Diatomeae, 
both  in  time  and  space,  are  the  most  extensive,  various,  and  wide,  of  all 
organic  beings.  In  fresh,  in  salt,  and  in  brackish  waters  they  are  ahke  foimd ; 
they  exist  abundantly  in  a  h^ing  state  about  the  roots  of  plants  and  diffased 
in  moist  earth ;  they  are  also  to  be  met  ^vith  in  the  dust  of  the  atmosphere 
and  in  meteoric  products.  They  are,  in  fine,  inhabitants  of  earth,  air,  and 
water.  When  no  longer  ahve,  their  silicious  skeletons  preserve  their  form 
and  constant  characters,  iminjiu'ed  by  most  of  the  causes  which  obhterate 
the  remains  of  other  Hving  beings.  They  are  so.  preserved  in  most  of  the 
rocks  above  the  oldest  primaiy — in  all,  indeed,  in  which  intense  heat  has  not 
operated  to  fuse  sihca  into  a  molten  mass.  At  the  present  day  they  are 
ejected  from  the  bowels  of  the  earth  in  the  lava,  cinders,  and  ashes  of  vol- 
canos,  and  are  borne  about  by  the  winds  from  one  continent  to  another  in 
showers  of  dust. 

In  respect  of  habitat,  the  Diatomeae  are  divisible  into  marine  and  fresh- 
water species ;  some  indeed  are  common  to  both  fresh  and  salt  water,  or 
exist  in  brackish  water.  The  following  accoimt  of  the  habitats  of  Diatomeae, 
illustrated  by  reference  to  particular  examples,  is  from  the  experienced  pen 
of  Mr.  Ralfs,  who  has  supplied  us  with  it : — 

"  The  Diatomeae  may  be  obtained  at  all  seasons  of  the  year,  but  are  most 
plentiful  in  spring  and  summer,  many  of  them  indeed  being  hmited  to  that 
period ;  thus  the  species  of  Micromega  and  Schizonema  are,  with  few  excep- 
tions, in  perfection  only  in  May  and  June,  when  they  are  met  with  in  shel- 
tered situations,  forming  wide  patches  on  the  ground  and  on  the  flat  surfaces 
of  rocks  exposed  at  ebb-tide.  About  the  end  of  May  the  Enteromorpha 
compressa,  so  common  on  our  shores,  often  seems  as  if  faded  at  the  end ;  this 
appearance  is  frequently  accompanied  by  the  presence  of  Grammonema  Jur- 
gensii,  which  is  easily  recognized  by  its  slippery  feel,  when  from  its  pale 
colour  it  would  otherwise  escape  detection. 

''  At  all  seasons  of  the  year,  the  smaller  and  more  slender  Algae,  marine 
and.  freshwater,  as  soon  as  they  attain  maturity,  become  almost  invariably 
covered  ^vith  parasitic  Diatomeae,  which  impart  to  them  a  brownish  colour. 
In  this  way  we  obtain  species  of  Cocconeis,  Achnanthes,  Striatella,  Tahellaria, 
Grammatophora,  Isthmia,  Gornphonema,  Podosphenia,  Rhipidophora ,  and 
Si/nedra.  On  the  contrary,  Amphitetras  and  Biddulphia  prefer  the  muddy 
cre\ices  in  the  sheltered  sides  of  pei-pendicular  rocks. 

*'  In  salt  marshes  we  may  expect  to  find  the  Achnanthes  subsessilis  on  the 
slender  filaments  of  Etiteromorpha,  but  so  sparingly  as  hardly  to  discolour 
them.  The  species  of  Epithemia  are  parasitic  on  Claclophora,  both  in  brackish 
and  in  freshwater  pools.  The  Melosirce  are  common  in  marshes,  especially  at 
the  mouths  of  large  rivers,  where  they  form  Conferva-hke  brownish  masses. 
"  Many  of  the  unattached  Diatomeae  are  produced  in  dark  brown  patches 


76  GENEEAL  HISTOEY  OF  THE  OFUSOEIA, 

at  the  bottom  of  pools,  or  on  the  surface  of  mud ;  the  freshwater  species 
often  by  the  road-side  ;  the  marine  forms  usually  near  high-water  mark.  Am- 
pMpleura  injiexa  and  A.  scalaris  congregate,  in  large  brown  stains  or  spots, 
on  the  muddy  sides  of  rocks,  whilst  other  species,  for  instance  CampijlodiscuSj 
and  Coscinodiscus  concinnus,  form  similar  collections,  but  prefer  more  shady 
situations. 

''  The  sides  of  ditches  in  brackish  marshes  are  very  prolific,  especially  after 
spring-tides,  and  in  situations  not  again  covered  until  the  next  high-tides. 
We  may  expect  to  gather  in  such  places  species  of  Smnrella,  Navicida,  Pleu- 
7'osigma,  Ceratoneis,  Amphiprora,  Amphora,  &c.  The  soil  about  the  roots  of 
rushes  and  of  other  plants  inhabiting  salt  marshes  often  aiford  interesting 
forms,  but  seldom  in  abundance.  We  find  there  species  of  Coscinodiscus  and 
of  Zygoceros ;  but  such  are  obtained  more  abundantly  from  the  mud  or  from 
the  washings  of  bivalve  shells  brought  uj)  from  deep  w^ater  or  collected  at  the 
mouths  of  rivers.  Oyster-beds  are  in  general  productive.  The  Bac'illaria 
paradoxa  inhabits  ditches  in  w^hich  the  water  is  nearly  fresh,  and  is  frequently 
obtainable  from  the  scum  diiven  from  the  siuface  to  the  banks. 

"  Pew  Diatomeae  are  peculiarly  autumnal ;  we  have,  however,  gathered 
Homoeocladia  Martiana,  Berheleya  fragilis,  DicTcieia  pinnata,  and  Striatella 
umpmictata,  chiefly  at  that  season.  . 

"  On  warm  siunmer  days,  Diatomeae,  with  various  microscopic  Algae  and 
Fungi,  rise  to  the  siu-face  of  water  by  the  disengaged  oxygen  gas  still  ad- 
hering to  them  and  buojing  them  up,  and  there  form  a  dehcate  film  or  a 
scum,  and  at  times  even  a  layer  of  considerable  thickness.  Such  collections 
are  rich  in  species  of  Navicida,  CgmheUa,  Surirella,  and  Si/nedra.  When  an 
entangled  larger  mass  is  formed,  there  is  usually  one  prevailing  species. 
Specimens  of  Fragilaria  are  generally  found  on  decapng  wood  or  leaves, 
or  amongst  Confervae  diffused  in  the  water.  From  the  drainings  of  Sphagnum 
may  often  be  obtained  Synedra  biceps  and  various  species  of  Himantidium. 
Boggy  soil,  especially  when  situated  on  a  slope,  affords  various  species  of  Epi- 
themia  and  Navicula ;  so  hkemse  does  the  soft  matter  on  rocks  on  which  water 
constantly  trickles.  Washings  from  oysters  and  the  refuse  raised  by  trawlers 
are  usually  rich  in  spheres  of  Coscinodiscus,  Actinoptychiis,  Pleurosigma,  Di- 
pJoneis,  Navicida,  Dictyocha,  &c.  The  same  kind  of  washings  from  sheltered 
harbours  give  Surirella  fastuosa,  Auliscus  scidptus,  together  with  species  of 
Campylodiscus,  Triceratimn,  &c.  Washings  of  corallines  are  like^vise  some- 
times productive." 

Mr.  Norman  supplies  us  with  the  following  hints  : — "  The  most  interesting 
forms  occur  in  salt  water,  especially  in  shallow  lagoons,  saltwater  marshes, 
estuaries  of  rivers,  pools  left  by  the  tide,  &c.  Their  presence  in  any  abun- 
dance is  shown  by  the  colour  they  impart  to  the  aquatic  plants  they  are 
attached  to  ;  or  when  found  on  mud,  by  the  yellowish-brown  film  they  form 
on  the  surface,  and  which,  if  removed  with  a  spoon  mthout  disturbing  the 
mud,  will  be  found  a  very  pure  deposit. 

"  Such  collections  are  best  put  at  once  in  bottles,  or  even  partially  dried 
and  wrapped  in  pieces  of  paper  or  tin-foil.  When  placed  in  bottles,  a  few 
drops  of  spirit  are  advantageously  added.  In  all  cases  it  is  essential  that  the 
locahty  whence  obtained  should  be  plainly  written  on  each  package.  Capital 
gatherings  are  obtainable  by  carefully  scraping  the  brownish -coloured  layer 
from  mooring-posts,  or  the  piles  of  wharfs  or  jetties. 

""  In  clear  running  ditches,  the  plants  and  stones  have  often  long  streamers 
of  yellowish-brown  slimy  matters  adhering  to  them,  generally  composed  almost 
wholly  of  filamentaiy  species.  The  layers  of  Diatomaceous  fronds  on  the 
surface  of  mud  are  often  covered  with  bead-hke  bubbles  of  oxygen,  which 


OP  THE  diatohe-t:.  77 

from  time  to  time  rises  to  the  sm-face  of  the  water  and  carries  up  with  it 
some  of  the  deposit  in  the  form  of  a  scum,  Avhich  gets  blown  to  leeward,  and 
may  be  readily  collected  from  the  edge  of  the  pond  quite  free  from  particles 
of  mud  and  other  impurities. 

"  Good  and  rare  specimens  have  been  obtained  from  the  stomachs  of  Ho- 
lothuridae  and  other  Mollusca  which  inhabit  deep  water,  and  are  often  thrown 
on  shore  after  severe  gales  of  v^dnd.  These  animals  may  be  merely  dried  and 
preserved  just  as  found,  and  the  contents  of  the  stomach  obtained  afterwards 
by  dissection.  Shells  and  stones,  covered  with  seaweed,  &c.,  from  deep  water, 
also  afford  most  interesting  and  little-known  forms.  The  rougher  these  are, 
the  better  (they  ought  by  no  means  to  be  cleaned).  Deep-sea  soundings 
(especially  those  from  great  depths)  should  be  presei-ved ;  for  they  are  often 
exclusively  DiatomaceoiLS. 

"  Yerv  rare  species  have  often  been  fonned  in  immense  quantities  in  the 
arctic  and  antarctic  regions  by  melting  the  '  pancake  ice,'  rendered  brownish 
by  these  microscopic  shells.  The  sea  is  also  often  observed  discoloiu^ed  with 
brownish  patches,  which  should  be  collected,  and  the  water  filtered  through 
blotting-paper  or  cotton  wool :  the  residuum  will  frequently  turn  out  to  be 
composed  of  Diatomeae.  It  is  also  highly  interesting  to  collect  and  examine 
the  impalpable  dust  which  occasionally  falls  into  the  folds  of  the  sails  of  ships 
at  sea." 

Scallops  and  other  MolliLSca  often  contain  rich  and  rare  collections  in  their 
stomachs.  In  Ascidia  (e.  g.  Phallusia  sulcata^  Ascidia  mentula)  Mr.  ISTorman 
and  the  Rev.  E.  CressweU  found  an  abundant  source.  Mr.  J^orman  adds,  in 
a  further  note  kindly  sent  us — "  The  Ascidians,  whose  stomachs  are  almost 
always  so  loaded  with  Diatomaceous  frustules,  are  to  be  found  abundantly 
on  the  shells  of  oysters  dredged  in  deep  water,  and  readily  procurable  from 
the  trawlers. 

"  The  Salpce  (found  so  abundantly  floating  on  the  surface  of  the  sea  in  warm 
latitudes)  aflbrd  very  pure  gatherings.  The  roots  of  the  various  species  of 
mangrove,  growing  in  the  dense  swamps  of  rivers  and  estuaries  in  the  tropical 
regions  of  Africa,  Australia,  and  the  Eastern  Archipelago,  are  said  to  be  fre- 
quently covered  with  a  brownish  mucous  shme  very  rich  in  Diatomese.  I 
liave  also  obtained  very  pure  gatherings  from  the  roots  of  the  Dutch  rushes, 
as  imported,  and  from  the  Zostera  marina  from  the  Baltic,  used  for  stuffing 
beds,  &c.,  by  upholsterers.  Stones,  moreover,  brought  as  ballast  from  abroad, 
will  amply  pay  the  diligent  collector  by  yielding  foreign  and  perhaps  rare 
species.  The  roots  of  aquatic  plants  from  tropical  countries,  stored  in  her- 
baria, would,  if  properly  examined,  peld  many  interesting  forms  of  Diatoms." 

Indeed  we  may  add,  generally,  that  the  roots  of  land  plants,  particularly 
of  mosses,  hchens,  &c.,  growing  around  trees  on  the  ground,  or  upon  them, 
are  fniitful  in  Diatomese,  and,  in  fact,  of  some  of  the  rarer  fonns.  In  the 
■N^umber  of  the  Microscoincal  Transactions  just  published  (July  1858,  p.  79), 
Col.  Baddeley  notes  the  occurrence  of  Diatoms  in  considerable  numbers  in 
the  Koctiluca  miliaris.  They  are  the  chief  constituents  of  a  mass  of  dark 
matter  near  the  nucleus,  and  lie  in  the  so-called  vacuoles,  into  which  they 
enter  from  the  mouth.  This  occurrence  suggests  an  easy  method  of  obtaining 
different  marine  species  of  Diatomese  in  their  natural  state,  often  alive,  and 
with  their  endochrome  perfect.  The  Colonel  discovered  in  this  way  several 
rarer  species,  and  gives  a  list  of  nearly  50  which  he  identified,  besides  not  a 
few  forms  of  whose  true  name  he  was  uncertain.  To  extract  the  Diatoma- 
ceous mass  from  the  interior  of  the  Noctilucce,  Col.  Baddeley  recommends 
that  the  seawater  and  its  h\'ing  freight  be  poured,  on  arriving  home,  in  a 
white  hand-basin,  and  be  let  stand  for  an  hour  or  two.     "  This  rough  treat- 


iO  GENERAL  HISTORY  OF  THE  INFUSOEIA. 

ment  causes  these  creatures  to  disgorge  their  food ;  and  if,  after  an  interval, 
the  water  be  carefully  poured  off,  a  sediment  will  be  found  at  the  bottom, 
which  will  consist  of  Diatoms  mixed  with  some  refuse." 

Dr.  Donkin  lately  (T.  M.  S.  1858,  p.  11)  called  attention  to  the  occiuTence 
of  that  rare  form,  Syndendrimn  diadema,  in  the  stomach  of  the  lobster,  and 
in  a  subsequent  paper  {op.  cit.  p.  14)  alludes  to  the  abundant  deposit  of  Uving 
Diatoms  upon  the  sands  at  the  sea-side,  in  the  follomng  paragraph : — 
"  Professor  Smith  states  that  '  the  shallow  pools  left  by  the  retiring  tide  at 
the  mouths  of  our  larger  rivers '  are  the  favourite  habitat  of  marine  species. 
But  such  localities  I  have  found  not  to  be  half  so  prolific  in  species  as  the 
smids  of  stdl  bays,  or  the  sJiore,  where  they  are  exposed  hy  the  reflux  of  the 
tide,  at  a  distance  corresponding  ivith  the  half-tide  margin.  In  these  places, 
where  the  sands  are  sloping  towards  the  sea,  and  grooved  out  into  small 
fuiTows,  filled  -with  salt  water  oozing  out  from  behind,  the  abundance  of 
Diatoms  aggregated  into  a  living  mass  imparts  to  the  surface  of  the  sand 
difi'erent  hues  of  chestnut  and  oHve,  the  difterence  of  colom-  being  due  to 
the  natiu'e  of  the  species  present.  These  coloured  patches,  it  is  interesting 
to  observe,  are,  during  the  sunshine,  studded  with  numerous  minute  air- 
bubbles,  undoubtedly  given  off  by  the  Diatoms  themselves. 

^'  To  separate  the  Diatoms  thus  detected,  from  the  surface  of  the  sand,  I 
found  to  be  impossible.  I  therefore  seized  hold  of  the  nearest  bivalve  shell 
which  happened  to  lie  in  the  way,  and  with  this  I  carefuUy  scooped  up  the 
surface  of  the  coloured  sand.  This  I  emptied  into  a  wide-mouthed,  stoppered 
bottle,  capable  of  holding  eight  ounces,  until  half  full ;  the  other  half  of  the 
bottle  I  filled  up  with  salt  water.  I  then  shook  the  whole  briskly  and  allowed 
the  bottle  to  stand  for  a  short  period.  The  sand,  being  composed  entirely  of 
fine  round  grains  of  quartz  and  the  minute  fragments  of  shells,  settled  at  the 
bottom  in  a  few  seconds,  leaving  the  Diatoms  all  suspended  in  the  water 
above,  and  forming  by  their  abundance  a  chestnut-coloured  cloud,  but  not 
more  than  1  part  in  1000  of  the  whole  sand  collected.  The  coloured  water 
was  then  poured  into  another  bottle,  and  formed  the  gathering,  while  the 
sand  was  thrown  away.  The  Diatoms,  in  theii'  tiu^n,  were  separated  from  the 
superfiuous  water  by  subsidence,  and  brought  home  in  l|-oz.  bottles.  In  this 
manner  I  soon  found  that  any  quantity  could  be  collected  in  a  pure  and  un- 
mixed condition,  affording  an  excellent  opportunity  of  examining  their  living 
forms,  and  one  of  which  I  availed  myself  on  Qxevj  occasion. 

*'  After  carefully  exaroining  materials  collected  in  this  way  from  various 
parts  of  the  beach,  I  -detected  not  less  than  about  100  species,  all  these 
strictly  marine,  and,  with  a  few  exceptions,  each  species  in  considerable 
abundance." 

The  fact  of  Diatomeae  rendeiing  themselves  perceptible  to  common  vision 
by  their  excessive  accumulation  and  the  coloiu"  they  impart  to  water,  is  illus- 
trated by  the  phenomenon  of  coloration  of  the  sea  recorded  by  Dr.  Hooker, 
also  by  the  Melosira  ochracea,  which  occui's  in  many,  perhaps  in  all,  cha- 
lybeate waters,  and  also  in  peat  water  containing  a  small  proportion  of  iron. 
It  is  of  the  colour  of  ii^on  rust,  and  in  mineral  springs,  in  which  it  abounds, 
is  often  taken  for  precipitated  oxide  of  iron.  It  covers  everything  under 
water,  but  forms  so  delicate  and  floccose  a  mass  that  the  least  motion  dissi- 
pates it.  In  the  spring  of  the  year  this  mass  is  composed  of  very  delicate, 
pale-yellow  globules,  which  can  be  easily  separated  from  each  other.  They 
unite  together  in  rows  like  short  chains,  and  produce  an  irregular  gelatinous 
felt  or  floccose  substance.  About  summer,  or  in  autumn,  they  become  de- 
veloped into  more  evidently  articulated  and  stiff  threads  of  a  somewhat  larger 
diameter,  but  still  form  a  complicated  mass  or  web,  and,  either  from  adhering 


OF  THE  DIATOME.E. 


'9 


to  each  other  or  to  delicate  Confei-vae,  appear  branched.  In  the  young  con- 
dition, when  examined  under  shallow  magnifiers,  they  resemble  gelatine ;  but 
with  a  power  of  300  diameters  the  flexible  granules  are  discoverable,  and, 
with  dextrous  management,  the  little  chains  forming  the  felt  or  fioceose 
web  can  be  made  out.  In  summer,  on  the  other  hand,  its  structiu^e  can  be 
observed  much  more  easily  and  distinctly.  Early  in  spring  the  coloiu'  is  that 
of  a  pale  yellow  ochre,  but  in  summer  that  of  an  intense  rusty  red.  Other 
examples  occur  where  a  single  species  becomes  tangible  to  the  unaided  senses  ; 
such  are  met  with  in  the  brown  specks  mentioned  in  the  preceding  account  of 
habitats  formed  by  particular  species  upon  the  larger  Algse  and  Confervse.  So 
the  GompJionema  geminatum  forms  on  rocks  tufts  of  a  spongy  texture  and 
brownish  coloiu'  when  young,  but  white  aftei^wards.  The  St/nedra  Uhm  often 
produces  a  white  incrustation  on  stones  in  rivers  in  summer ;  and  Fragilaria 
and  Odontidium  are  seen  outstretched  as  dehcate  brown  filaments,  several 
feet  in  length,  like  many  filiform  Algce,  from  which,  however,  they  differ  by 
breaking  up  so  very  readily,  on  the  least  disturbing  force,  into  their  separate 
joints.  ^' Large  numbers  of  Rhizoselenia''  (writes  Mr.  Brightwell,  J.  M.S. 
1858,  p.  95)  "have  been  detected  in  the  stomachs  of  Salj^ce,  and  they  have  also 
been  observed  floating  free  in  the  ocean  in  vrarm  latitudes,  their  appearance 
being  that  of  httle  confervoid  flakes  of  exquisite  dehcacy,  but  of  a  sufiicient 
aggregation  of  filaments  to  be  seen  by  the  naked  eye.  The  mass  appeared 
(probably  from  the  endochrome)  of  a  faint,  evanescent,  ochraceous  colour." 
Moreover,  the  frondose  species  generally  attain  an  appreciable  magTiitude. 
Thus  Encyonema  prostratum  forms  a  tuft-like  stratum, — when  recent,  dark 
brown,  but  when  dried,  of  a  dull  green  colour.  Schlzonema  suhcohcerens  grows 
into  tufts  from  a  quarter  to  half  an  inch  or  more  high ;  and  S.  vidgare  con- 
stitutes a  dark  bro^Ti  gelatinous  stratiun  on  stones  in  shallow  water,  fila- 
ments simple  or  nearly  so  in  deep  still  water,  and  much  branched  filaments 
in  deep  rapid  streams. 

Mr.  I^orman,  of  Hull,  has  most  kindly  furnished  us  with  the  following 
original  observation  on  the  growth  of  one  species,  the  Campylodiscus  cos- 
tatus : — "  In  the  early  part  of  the  spring  of  1856,"  he  "«T:ites,  "  I  made  a 
gathering  of  freshwater  Diatomere  from  the  '  Spring  Ditch,'  Hull.  Although 
I  met  Tvith  a  few  odd  finistules  of  the  species  named,  I  did  not  consider  it  of 
sufiicient  interest  to  boil  in  acid  for  moimting,  and  the  phial  containing  them 
was  left  in  the  window  of  my  laboratory  during  the  ensuing  summer.  Some 
time  in  the  autumn  I  had  occasion  to  make  use  of  this  bottle,  and  was  on  the 
point  of  thro^ving  away  the  contents,  when  I  noticed  the  sui'face  of  the  de- 
posit and  the  sides  of  the  bottle  to  be  covered  A\'ith  a  dense  brown  growth  of 
Diatoms.  On  further  exarmination  I  found  an  immense  colony  of  Campylo- 
discus, which  gave  by  preparation  some  beautifully  pui'e  slides  of  thi§  species. 
In  removing  the  upper  layer  I  purposely  left  a  few  of  the  frustules  in  the 
bottle,  which  was  again  placed  in  the  window.  These  have  again  increased 
to  a  great  extent,  and  now  (December  1857)  they  appear  to  thrive  in  perfect 
health.  Does  not  this  occiUTence  suggest  an  easy  plan  of  prociu^ing  in  a 
pure  state  such  forms  as  are  rarely  found  together  in  any  abundance  ?  " 

Geogeaphical  Distribution. — Species  of  Diatomeae  are  for  the  most  part 
distributed  over  a  very  wide  geographical  area.  Some,  indeed,  would  seem 
cosmopolitan,  whilst  others  are  limited  to  certain  regions.  For  instance,  the 
Terpsinoe  has  not  been  discovered  in  Eiu'ope  ;  and  Synedra  Entomon  is 
reckoned  by  Ehrenberg  as  peculiarly  a  South  American  production.  This 
author  has  given  full  force  to  this  seeming  fact,  and  employed  it  in  the  en- 
deavour to  discover  the  origin  and  course  of  meteoric  dust,  and  also  to  arrive 
at  certain  geological  deductions.      For  example,  he  says  {Monatsh.  Berlin, 


80  GENEKAL  HISTORY  OF  THE  IXEUSOHIA. 

Akad.  1849),  "  The  chain  of  rocky  mountains  traversing  the  continent  of 
North  America,  forms,  Avith  reference  to  the  distribution  of  Infusoria,  a 
stronger  barrier  between  California  and  Oregon,  and  the  rest  of  the  continent, 
than  does  the  Pacific  Ocean,  with  Chraa,  between  the  western  plains  of 
North  America  and  the  region  of  Siberia.  Thus,  the  United  States,  with 
Mexico,  never  present  any  of  the  forms  characteristic  of  Oregon  and  Cali- 
fornia, whilst,  on  the  other  hand,  the  peculiar  forms  of  these  latter  countries 
are  met  mth  in  Siberia.  All  this  is  remarkably  confii^med  in  this,  that  the 
gold  region  of  the  Sacramento,  in  the  extent  and  abundance  of  its  Infusorial 
products,  finds  its  parallel  only  in  Siberia." 

This  presumed  fact  of  limited  geographical  distribution  is  thus  applied 
by  Ehrenberg  m  another  paper  (Monatsh.  18-16) : — "  The  atmospheric  dust 
which,  since  1830,  has  fallen  in  the  Atlantic  Ocean  as  far  as  800  miles  west 
from  Africa,  on  the  Cape  de  Yerde  Islands,  and  even  in  Malta  and  Genoa, 
has  been  all  of  an  ochre-yellow  colour,  never  grey  like  the  dnst  seen  in  the 
north  of  Africa,  and  consists  of  from  -i-th  to  k'd  of  organic  particles  referable 
to  90  species,  the  greater  number  of  which  are  of  freshwater  habit,  and  found 
equally  in  the  most  "widely  separated  regions  named.  This  dust,  even  in 
Genoa,  whence  it  is  carried  by  the  Sirocco  wind,  contains  no  characteristic 
African  forms,  but,  on  the  contrary,  presents  the  Si/nedra  Entomon,  a  deci- 
dedly characteristic  species  of  South  America."  From  his  observations  on 
this  meteoric  dust,  Ehrenberg  concludes  that  there  is  a  current  of  aii'  imiting 
Africa  and  America  in  the  region  of  the  trade  winds,  and  occasionally  dii'ected 
towards  Eui^ope.  On  the  other  hand,  their  wide  diffusion  is  exemplified  in  Dr. 
Hooker's  Report  on  the  Diatomaceous  vegetation  of  the  Antarctic  sea  {Brit, 
Assoc.  1847)  : — "  The  genera  and  species  of  Diatomaceoe  collected  within  the 
Antarctic  sea  are  not  at  all  peculiar  to  those  latitudes ;  on  the  contrary,  some 
occur  in  every  country  between  Spitzbergen  and  Victoria  Land.  Others,  and 
even  some  of  these,  have  been  recognized  by  Ehi-enberg  as  occurring  fossil 
in  both  Americas,  in  the  south  of  Europe  and  north  of  Africa,  in  Tripoli 
stone  and  in  volcanic  ashes  ejected  both  from  active  and  extinct  volcanos, 
whilst  others  again  exist  in  the  atmosphere  overhanging  the  tropical  At- 
lantic." 

Prof.  Smith  has  the  foUo^ving  remarks  on  cosmopolitan  or  very  widely- 
difiused  species  (Sr/nops.  ii.  p.  xxvii)  : — 

"  Of  freshwater  species  frequent  in  the  British  Islands,  the  following  seem 
almost  cosmopolitan,  viz.  Si/nedra  radians,  Pinnularia  vir^idis,  Pinnidaria 
horealis,  and  Cocconema  lanceolatwn.  Gatherings  from  many  locaHties  in 
Europe,  from  Smyi-na  and  Ceylon,  from  the  Sandmch  Islands,  New  Zealand, 
and  New  York,  from  the  loftiest  accessible  points  of  the  Himalaya  in  Asia, 
and  the  Andes  in  America,  have  supplied  specimens  of  these  forms. 

*'  Navicula  seriam  abound  in  all  our  mountain  bogs,  and  is  equally  common 
in  the  marshes  of  Lapland  and  America. 

"  Epitheinia  gihha  is  an  inhabitant  of  the  Geysers  of  Iceland  and  the  lakes 
of  Switzerland. 

*'The  South  Sea  Islands  supply  Stauroneis  acuta,  and  Ceylon  Synedra 
Ulna,  while  Stauroneis  Phoenicenteron  is  equally  abundant  in  Britain,  Sicily, 
and  Nova  Scotia. 

''These  notes  of  localities  will  give  some  idea  of  the  wide  distribution  of 
our  fluviatile  Diatomaceae :  more  numerous  gatherings  would,  no  doubt, 
greatly  extend  the  list ;  and  the  following  circumstance  \vi\l  show  how  gene- 
rally our  commoner  British  forms  are  diffused  throughout  European  localities 
that  have  been  carefully  examined.  During  a  tour  in  Languedoc  and  the 
Auvergne  in  the  spring  of  1854,  I  made  upwards  of  forty  gatherings  from 


OF  THE  DIATOME^.  81 

the  rivers,  streams,  and  lakes  of  the  district  I  traversed.  In  these  I  detected 
130  sjDecies,  and  but  one  form  not  yet  determined  as  indigenous  to  Britain. 
If  this  be  the  case  with  a  district  much  of  whose  Phanerogamous  flora  is  so 
different  from  our  own,  it  bears  out  the  \iew  I  have  taken,  that  these  or- 
ganisms enjoy  a  range  of  distribution  far  more  general  than  the  higher  orders 
of  plant -life. 

''  Nor  is  the  distribution  of  marine  species  less  notable  for  its  extent  and 
uniformity.  Coscinodiscus  eccentrkus  and  C.  7'adiatus  range  from  the  shores  of 
Eritain  to  those  of  South  Africa.  Gmmmatopliora  marina  and  G.  macilcnta  are 
found  in  almost  every  marine  gatheiing  from  the  Arctic  Ocean  to  the  Mauri- 
tius. Stauroneis pidchella,  Cocconeis  SciiteUiim,  and  Bkldulj[>hia  pulcliella  are 
equally  abundant  on  the  Eiu'opean,  the  American,  and  the  African  coasts, 
while  lihabdonema  Adriaticum  belies  its  name  by  its  occurrence  in  the  Indian, 
Atlantic,  and  Pacific  Oceans.  During  the  researches  already  mentioned,  in  the 
South  of  France,  I  made  several  prolific  gatherings  on  the  shores  of  the  Gulf 
of  Lyons;  but,  of  33  fonns  occurring  in  these,  HyaJosira  deUcatida,  Kiitz., 
was  the  only  one  not  famihar  to  me  as  a  British  species." 

The  supposition  that  many  species  of  Diatomeae  occupy  a  very  limited  geo- 
graphical area,  and  that  considerable  numbers  have,  in  course  of  ages,  disap- 
peared or  become  extinct,  as  many  animal  and  vegetable  organisms  have  done, 
was  thus  ably  examined  by  the  lamented  Dr.  Gregory  in  a  communication  to 
the  Royal  Society  of  Edinburgh,  made  in  1856  (Proc.  Boy.  Soc.  Edin.  1856- 
57,  p.  442).  The  subject  of  discussion  is  introduced  in  his  notice  of  Ma- 
vicida  prcetexta,  a  form  previously  considered  only  fossil.  "  I  have,"  he  says, 
*'  selected  this  form  because  the  bed  in  wliich  it  occurs  fossil  is  the  oldest  in 
which  Ehrenberg  has  found  any  Diatoms.  He  has  indeed  found  microscopic 
organisms  in  the  chalk,  and  even  in  older  rocks,  among  which  he  mentions 
the  mountain  Hme^tone  and  the  Silurian  greensand.  But  the  forms  in  the 
two  latter  rocks  are  not  numerous,  and,  as  well  as  those  Avhich  abound  in  the 
chalk,  belong  to  the  Foraminifera  or  to  the  Polycystina,  not  to  the  Diato- 
macea ....  In  short,  I  have  no  hesitation  in  saying,  that  I  believe  all  the  forms 
in  the  ^gina  clay-marl,  which  is  the  -oldest  Diatomaceous  deposit  yet  de- 
scribed, will  be  found  living  on  our  coast."  The  stratum  at  -^gina  belongs 
either  to  the  chalk  formation,  or  to  the  oldest  tertiary  or  Eocene  beds. 

Dr.  Gregory  continues,  "  It  may  also  be  observed  that,  of  all  the  forms 
figured  by  Ehrenberg  from  more  recent  strata,  whether  mioeene,  like  the  bed 
on  which  the  town  of  Richmond  (Virginia)  is  built,  and  several  kinds  of  Bcrg- 
mehl — or  phocene,  like  other  Berg-mehls  or  pohshing- slates,  &c. — or  stiU 
more  recent,  the  great  majority  are  perfectly  identical  wdth  existing  Diatoms. 
Indeed,  although  many  forms  are  stated  in  Ehrenberg's  earhest  writings  to 
be  fossil  only,  and  have  been  supposed  to  be  extinct,  the  progress  of  obser- 
vation is  continually  adding  to  the  number  of  species  which  are  found  also  in 
the  recent  state.  Thus,  for  example,  the  whole  group  of  dentate  Eunotke, 
which  abound  in  the  Lapland  and  Finland  Berg-mehls,  were  long  thought  to 
be  only  fossil ;  but  they  have  been  nearly  aU  found  in  America,  and  I  have 
myself  seen  several  of  them  recent  in  this  countiy.  Eunotia  triodon,  long 
supposed  to  be  extinct,  occurred  scattered  in  many  of  the  Scottish  freshwater 
gatherings. 

"  Taking  these  facts  into  consideration,  I  am  led  to  beheve  that  we  have  no 
evidence  that  any  species  of  Diatom  has  become  extinct,  as  so  many  species, 
and  even  genera  and  tribes,  of  more  highlj'  organized  beings  have  done.  I 
obser\^e  that  Mr.  Brightwell  expresses  a  similar  opinion  in  his  valuable  paper 
on  Chcetoceros  (J.  M.  S.  iv.  p.  105)." 

Wherefore  Dr.  Gregory  comes  to  the  conclusion,  that  ''  the  whole  of  the 

G 


82  _  GENERAL  HISTORY  OF  THE  INFUSORIA. 

speciea  wJiicli  occur  fossil  will,  ere  long,  be  detected  in  the  recent  state.  It 
is  at  all  events  certain  that  a  very  large  proportion  of  the  Diatoms  found  in 
the  fossil  state  also  occur  in  the  living  state,  and  that  every  day  adds  to  their 
number.  There  is  at  present  no  good  evidence  of  the  existence  of  Diatoms 
earlier  than  the  chalk,  if  so  early.  But  we  must  not  forget  that  the  shells 
of  Diatoms  appear  to  be  altered  by  long  contact  with  carbonate  of  lime,  so 
that  they  may  have  existed  at  one  time  in  the  chalk.  We  find  them,  how- 
ever, in  spite  of  the  action  of  calcareous  matter,  in  the  recent  chalk-marls  of 
Meudon  and  of  Caltanisetta,  which  are  rather  more  recent  than  the  chalk, 
and  probably  of  about  the  age  of  the  clay-marl  of  ^gina.  If,  as  I  believe, 
no  Diatoms  have  become  extinct,  this  may  perhaps  depend  on  their  minute 
size  and  extreme  simplicity  of  structure,  which  probably  render  them  more 
indiiferent  to  climatic  changes  than  more  highly  organized  and  larger  beings. 
We  have  evidence,  to  a  certain  extent,  that  this  is  the  case ;  for  by  Ehren- 
berg's  figures  it  appears  that,  in  gatherings  of  recent  Diatoms  from  all  parts 
of  the  world,  in  every  possible  variety  of  climate,  the  majority  of  species  are 
identical  with  om-  own. 

*'  Diatoms,  therefore,  are  not  materially  affected  by  existing  differences  of 
climate,  and  have  probably  been  as  little  affected  by  the  geological  changes 
which  have  occurred,  at  all  events,  since  the  period  of  the  Eocene  deposits." 

Geological  Importance  of  Diatome^. — Fossil  Accumulations. — Although 
so  exceedingly  minute  and  apparently  insignificant  in  comparison  with  the 
animals  and  plants  usually  claiming  our  notice,  yet,  by  their  excessive  multi- 
plication and  accumulation,  they  assume  even  a  greater  importance,  in  the 
physical  history  of  the  earth,  than  the  largest  trees  or  animals  mth  which 
we  are  acquainted.  This  lesson  is  taught  us  by  hving  examples  of  these 
microscopic  beings  constituting  appreciable  masses,  and  by  innumerable  in- 
stances where  only  the  silicious  skeletons  remain,  in  a  fossil  or  semi-fossil 
condition. 

Ehrenberg  thus  illustrates  their  rapidity  of  production  and  accumulation. 
"  Silicious  Infusoria,"  he  says,  "form,  in  stagnant  waters  during  hot  weather, 
a  porous  layer  of  the  thickness  of  the  Jiand.  Although  more  than  100,000,000 
weigh  harcfly  a  grain,  one  may  in  the  coui'se  of  half-an-hour  collect  a  pound 
weight  of  them  ;  hence  it  will  no  longer  seem  impossible  that  they  may  build 
up  rocks.  However,  one  of  the  most  striking  examples  of  the  operation  of 
Diatomese  as  a  physical  agency  on  a  large  scale,  is  afforded  by  Dr.  Hooker's 
observations  addressed  to  the  British  Association  {Ueport,  1847).  He  saj^s — 
"  The  waters,  and  especially  the  newly-formed  ice  of  the  whole  Antarctic 
Ocean,  between  the  parallels  of  60°  and  80°  south,  abound  in  Diatomaceae, — so 
numerous  as  to  stain  the  sea  everywhere  of  a  pale  ochreous  bro^vn,  the  surface 
having  that  colour  as  far  as  the  eye  can  reach  from  the  ship.  Though  pecu- 
liarly abundant  in  the  ley  Sea,  these  plants  are  probably  uniformly  dispersed 
over  the  whole  ocean,  but,  being  invisible  from  their  minuteness,  can  only  be 
recognized  when  washed  together  in  masses,  and  contrasted  with  some  opake 
substance.  They  were  invariably  found  in  the  stomachs  of  Salpoe  and  of  other 
sea  animals,  in  all  latitudes  between  that  of  the  tropic  and  the  highest  parallel 
attained  in  the  Antarctic  expedition.  Their  death  and  decomposition  produce 
a  submarine  deposit  or  bank  of  vast  dimensions,  consisting  mainly  of  their 
silicious  shields,  intermixed  with  Infusoria  and  inorganic  matter.  Its  position 
is  from  the  76th  to  the  78th  degree  of  south  latitude,  and  occupies  an  area 
400  miles  long  by  120  wide.  The  lead  sometimes  sank  two  feet  in  this  pasty 
deposit,  and  on  examination  showed  the  bottom  made  up  in  great  measure  of 
the  species  now  living  on  the  surface.  This  deposit  may  be  considered  as 
resting  upon  the  shores  of  Victoria  Land  and  of  the  Barriers,  and  hence  on  the 


OF  TUE  DIATOME.E.  ^  83 

submarine  flanks  of  Mount  Erebus,  an  active  volcano  12,000  feet  high.  From 
the  fact  that  Diatomete  and  other  organisms  enter  into  the  formation  of 
pumice  and  ashes  of  other  volcunos,  it  is  perhaps  not  unreasonable  to  con- 
jecture that  the  subterranean  and  subaqueous  forces,  which  keep  Mount 
Erebus  in  activity,  may  open  a  direct  communication  between  this  Diato- 
maceous  deposit  and  its  volcanic  fires.  Moreover,  this  bank  flanks  the  whole 
length  of  Victoria  Barrier,  a  glacier  of  ice  400  miles  long,  whose  seaward 
edge  floats  in  the  ocean,  whilst  its  landward  extends  in  one  continuous  sweep 
from  the  crater  of  Mount  Erebus  and  other  mountains  of  Victoria  Land  to  the 
sea.  The  progressive  motion  of  such  a  glacier,  and  accumulation  of  snow  on 
its  surface,  must  result  in  its  interference  mth  the  deposit  in  question,  which, 
if  ever  raised  above  the  surface  of  the  ocean,  would  present  a  stratified  bed 
of  rock  which  had  been  subjected  to  the  most  violent  disturbances." 

But  instances  of  the  abundance  of  silicious  organisms  in  sea-  or  river- 
bottoms  are  to  be  met  with  nearer  home.  Mr.  Boper  has  explored  the  mud 
of  the  Thames  {J.  M.  S,  1854,  p.  68) ;  and  he  tells  us  that,  excluding  the 
coarse  sand,  nearly  one-fourth  of  the  finer  part  of  the  residuum  is  entirely 
composed  of  the  silicious  valves  of  difierent  species  of  Diatomeae, — ''  marine 
forms  prevailing."  This  writer  also  quotes  the  experience  of  Ehrenberg, 
who,  Avith  respect  to  the  mud  of  the  Elbe,  has  established  the  remarkable 
fact  that  at  Gluckstadt,  a  distance  of  40  miles,  and  even  above  Hambiu'g, 
upwards  of  80  miles  above  the  mouth  of  the  river,  marine  silicious- shelled 
Infusoria  were  found  alive,  and  theii'  skeletons  deposited  in  it  in  such  abun- 
dance, that  at  the  former  locality  they  form  from  one-quarter  to  one-third  of 
the  entire  mass,  and  that  the  proportion  is  stiU  about  one-half  that  amount 
at  Hamburg,  as  far  as  the  flood-tide  extends.  All  his  observations  gave  a 
great  predominance  of  marine  over  freshwater  species,  even  when  the  salt 
taste  of  the  water  was  no  longer  perceptible.  His  examination  of  the  mud 
of  the  Scheldt  and  Ems  fiu-nished  similar  results,  as  did  that  of  the  marine 
deposit  in  various  littoral  regions  of  the  North  Sea  and  Baltic. 

Reverting  to  the  Thames  deposit,  Mr.  Roper  expresses  his  beUef  that  the 
silicious  shells  "  have  a  perceptible  influence  in  the  formation  of  shoals  and 
mud-banks  in  the  bed  of  the  river.  ,  .  .  And  the  great  abundance  and  general 
chstribution  of  species  serve  to  illustrate  the  occurrence  of  similar  dejiosits 
in  a  fossil  state  at  localities  now  far  removed,  by  alterations  in  the  earth's 
surface,  from  the  streams  or  harbours  in  which  they  were  originally  de- 
posited. 

"  Another  point  worthy  of  attention  is  the  influence  of  these  organisms 
in  the  formation  of  deltas  at  the  mouths  of  large  and  slowly- flomng 
rivers — such,  for  instance,  as  the  Mississippi,  in  which  the  mean  velocity  of 
the  current  at  N'ew  Orleans  is  only  about  one  mile  and  a  half  per  hour  for 
the  whole  body  of  water.  Sir  Charles  Lyell,  from  experiments  on  the  pro- 
portion of  sediment  carried  down  by  the  river,  has  calculated  that,  taking  the 
area  of  the  delta  at  13,600  square  miles,  and  the  quantity  of  solid  matter 
brought  down  annually  at  3,702,758,400  cubic  feet,  it  must  have  taken  67,000 
years  for  the  whole  delta.  Now,  as  the  silicious  frustules  of  the  Diatomea) 
are  secreted  from  the  water  alone,  and  would  most  probably  be  extremely 
abundant  in  so  sluggish  a  stream  (especially  as  Prof.  Bailey  has  found  both 
marine  and  freshwater  species  abundant  in  the  rice-grounds),  there  can  be 
little  doubt  that,  without  taking  the  larger  proportion  noticed  by  Ehrenberg 
in  the  Elbe,  even  if  it  were  considerably  less,  it  would  reduce  the  above 
period  by  several  thousand  years  ;  and  the  same  cause  would  probably  apply 
wnth  equal  force  to  the  Ganges  and  Nile.  Ehrenberg  considered  that,  at 
Pillau.  there  are  annually  deposited  from  the  water  from  7200  to  14,000 

G  2 


84  GEXEEAL  HISTORY  OF  THE  LNFUSOEIA. 

cubic  metres  of  fine  microscopic  organisms,  which,  in  the  course  of  a  century, 
would  give  a  deposit  of  from  720,000  to  1,400,000  cubic  metres  of  infusory 
rock  or  Tripoli  stone." 

Another  fact  exemphfying  the  widely  pervading  presence  of  silicious  In- 
fusoria was  revealed  by  the  experiments  of  Ehrenberg,  viz.  their  existence 
in  a  h^ing  state  in  moist  earth  beneath  the  surface,  the  only  ^ital  condition 
necessary  being  a  small  quantity  of  moistiu^e.  The  presence  of  their  remains 
at  considerable  depths  in  mud  also  is  well  exemplified  by  the  experimental 
borings  made  by  Mr.  Okeden  {J.  M.  S.  1854,  p.  26)  at  Neyland,  a  creek  of 
IMilford  Haven,  where  deposits  rich  in  Diatomaceous  remains  of  marine  or 
brackish  and  freshwater  character  occurred  at  the  depth  of  20,  30,  and 
40  feet. 

The  preceding  illustrations  wiU  suffice  to  show  the  active  share  taken  by 
the  Diatomeae  at  the  present  day  in  the  ever-occiu-ring  changes  of  the  earth's 
siuface ;  others  must  now  be  adduced  to  exemplify  their  influence  in  the  past 
physical  changes  of  the  globe.  These  examples  are  so  numerous,  and,  relative 
to  other  phenomena,  so  important,  that  it  is  embarrassing  to  make  a  selection. 
Ehi-enberg  is  the  most  assiduous  cultivator  of  this  department  of  knowledge. 
He  has  personally  examined  deposits  collected  from  almost  every  countiy  of 
the  world,  and  described,  with  illustrative  plates,  the  genera  and  species  he 
has  encountered  in  them,  in  his  recent  large  work  the  Mihrogeologie,  1855. 
One  of  the  most  striking  and,  to  his  mind,  unique  instances  of  a  Diatoma- 
ceous deposit,  formed  at  a  remote  or  geological  period,  he  has  shoAvn  to  exist 
in  North  America,  on  the  banks  of  the  Colimibia  Eiver. 

The  river  of  Columbia,  in  its  course  at  Place-du-Camp,  rims  between  two 
precipices  700  to  800  feet  high,  composed  of  porcelain- clay  500  feet  thick, 
covered  over  by  a  layer  of  compact  basalt  100  feet  thick,  on  which,  again,  some 
volcanic  deposits  exist.  The  clay  strata  are  of  very  fine  grain,  and  vary  in 
coloiu' ;  some  are  as  white  as  chalk.  Dr.  Bailey  has  shown,  from  some  por- 
tions submitted  to  him  by  Col.  Fremont,  that  this  apparently  argillaceous  layer 
is  entirely  composed  of  freshwater  Infusoria.  Its  perfect  purity  from  sand 
shows  that  it  is  not  a  drift,  but  has  been  formed  on  the  spot.  By  its  immense 
thickness  of  500  feet,  this  layer  of  biohthic  Tripoli  far  surpasses  any  similar 
layers  elsewhere,  which  attain  ordinaiily  only  one  or  two  feet  thickness, 
although  those  of  Limebiu'g  and  Bilin  have  a  depth  of  40  feet.  Some  beds 
we  also  know  elsewhere  ha\ing  70  feet ;  yet  such  are  not  pure,  but  inter- 
sected by  strata  of  tufa  or  of  other  material. 

A  very  pm^e  Diatomaceous  deposit  has  been  met  with  by  Dr.  Gregory  in 
the  island  of  Mull,  which  when  diy  is  almost  white,  and  much  resembles 
chalk,  being  light,  pliable,  and  adherent  to  the  fingers  {T.  M.  S.  1853,  p.  93), 
and  in  composition  hardly  contains  anything  besides  silicious  organic  remains 
''  for  the  most  part  entii^e,  but  with  some  fragments ;  other  portions  which 
are  denser  contain  also  many  fi'agments  of  quartz  of  various  sizes,  and  vast 
numbers  of  comminuted  fragments  of  loric?e."  Prof.  Smith  {Sijnops.  vol.  i. 
p.  xii)  says — "Districts  recovered  from  the  sea,  in  the  present  or  other 
periods  of  the  earth's  histoiy,  frequently  contain  myriads  of  such  exuviae 
forming  strata  of  considerable  thickness."  Examples  of  this  nature  in  our 
own  coimtiy  are  met  with  in  "  the  ancient  site  of  a  mountain  lake  in  the 
neighbourhood  of  Dolgelly,  locahties  of  a  similar  kind  near  Lough  Island- 
Reavey  in  Down,  and  Lough  Moume  in  Antrim."  Mr.  Okeden  concludes, 
from  facts  collected  by  borings  in  the  mud  of  some  creeks  and  rivers  of 
South  Wales,  "  that  not  the  smface  merely,  but  the  whole  mass  of  these 
tidal  deposits  is  penetrated  by  these  minute  and  wondrous  organisms,  while, 
from  the  fact  of  their  being  foimd  at  Neyland  at  a  depth  of  40  feet  below  the 


OF  THE  DIATOME-E.  85 

present  surface,  and  close  upon  the  rock  which  forms  the  original  bed  of  this 
estuaiy,  the  mind  is  irresistibly  led  to  the  conclusion  that  they  have  existed 
there  from  the  time  when  the  waters  fii'st  rolled  over  the  spot." 

Berg-mehl,  Tripoli,  and  other  polishing-powders,  the  stratified  deposits  at 
Bilin  in  Bohemia  and  in  ^gina,  and  numerous  others  examined  and  reported 
on  by  various  microscopists  might  like"\vise  be  adduced  to  demonstrate  the 
important  part  played  by  these  individually  in\-isible  beings,  when  accumu- 
lated in  countless  mpiads,  in  the  construction  of  the  earth's  cnist. 

The  Oolitic,  and  even  some  earlier  metamorphic  rocks,  poq^hpitic  rocks, 
&c.,  are  not  wanting,  according  to  Ehrenberg,  in  species  of  Diatomeae ;  but 
in  the  Pliocene,  Miocene,  Eocene,  and  in  chalk  and  flint,  and  still  more  in 
the  tertiary  deposits,  the  abundance  and  variety  of  forms  are  greater.  Diato- 
maceous  shells  are  cuiiously  preserved  to  us  in  large  abundance  and  perfec- 
tion in  guano,  in  which  they  have  doubtless  entered  as  a  component  in  the 
way  of  mixture  Tvith  food  taken  by  the  bii'ds  which  have  deposited  that 
manui'e. 

The  foregoing  facts  teach  us  that  probably,  in  the  present  condition  of  our 
planet,  no  portion  of  its  siuface  is  destitute  of  Infusorial  life ;  and  now,  from 
the  prosecution  of  microscojDic  research  in  connexion  with  geological  facts, 
it  would  appeal'  that,  under  this  simplest  and  primary  form,  organic  Hfe  made 
its  fii'st  appearance  on  the  globe,  and  has,  during  the  many  epochs  of  this 
world's  histoiy,  and  notwithstanding  the  mightiest  changes  its  suiface  has 
undergone,  been  sustained  imtil  the  present  moment ;  and,  what  is  more,  so 
extraordinaiy  is  the  capability  of  the  silicious  Diatomeae  to  preserv^e  life,  and 
so  astonishing  theii'  powers  of  multipHcation,  that  species  which  are  now 
found  li\ing  have  their  generic  and  even  their  specific  types  at  the  very 
da^vn  of  creation.  Prof.  Ehrenberg  has  advanced  this  same  statement  in  his 
recent  work  (Mikrogeologie),  saying  that  the  oldest  sihcious  Infusoria,  whe- 
ther Carboniferous  or  Silurian,  belong  to  the  same  genera,  and  often  to  the 
same  species. 

Aeeolitic  Diatome^. — Ehrenberg  was  the  first  to  demonstrate  the  fre- 
quent existence  of  Diatomeae  along  with  other  microscopic  beings  and  or- 
ganic particles  in  the  atmosphere,  principally  in  those  showers  of  dust  which 
fall  from  time  to  time  in  various  parts  of  the  world,  and  in  those  other  mete- 
oric products  known  by  the  name  of  '  meteoric  paper '  and  '  blood-rain.'  In 
such  atmospheric  productions,  the  Berlin  natui^alist  has  detected  above  a  hun- 
di^ed  species ;  these,  accompanied  by  descriptions  and  figm^es,  and  prefaced 
by  an  account  of  aU  such  atmospheric  phenomena  on  record,  were  pubhshed 
by  Ehrenberg  in  a  large  brochure  entitled  "  Passatstaub  unci  Blutregen/' 
consisting  of  192  foho  pages.  An  extract  from  this  book  wiU  convey  the 
best  attainable  notion  of  the  physical  importance  of  these  aerial  dust-showers. 
The  quantity  of  actual  solid  matter  that  has  fallen  from  the  atmosphere 
by  showers  is  far  more  considerable  than  supposed ;  for,  though  it  falls  in  a 
diffused  dust-like  form,  the  extent  of  surface  covered  at  any  one  time  is 
veiy  considerable.  Comparing  it  vdth.  meteorolites,  Ehrenberg  obsei-ves  that 
the  total  quantity  of  these  stones  which  fell  between  1790  and  1819  weighed 
600  cwt.,  while  in  a  single  dust-shower  at  Lyons,  in  1846,  the  soHd  matter 
weighed  fuUy  7200  cwt.  Other  dust-stoims  in  Italy,  at  Cape  de  Yerd,  and  in 
other  localities  have  exceeded  even  that  at  Lyons,  in  the  quantity  of  matter 
precipitated  to  the  earth ;  and  Ehrenberg  suggests  to  the  imagination  the 
millions  of  tons  that  must  have  fallen  since  the  time  of  Homer.  Lastly,  he 
entertains  the  ciuioiLs  opinion,  that  this  meteoric  dust  does  not  necessarily 
derive  its  existence  from  the  earth's  surface,  and  from  the  force  of  atmospheric 
currents,  but  from  some  general  law  of  the  atmosphere,  according  to  which 


86  GENEEAL  HISTORY  OF  THE  INFUSOKIA. 

the  living  organisms  mainly   composing  it  may  have  the  power  of  self- 
development  in  the  aii\ 

Uses  of  Diatomaceous  Deposits. — The  utility  and  possible  and  probable 
piu-poses  of  these  minute  organisms  to  mankind  have  not  yet  met  with  due 
consideration.  Their  relation  to  the  soil,  in  which  they  are  so  abundant, 
and  their  influence  on  its  fniitfulness  are  matters  only  incidentally  reflected 
on  by  authors.  "  Sufficient  attention,"  remarks  Prof.  Gregory  (J.  M.  S. 
1855,  p.  2),  ''  has  not  yet  been  paid  to  the  fact  of  the  invariable  presence  of 
Diatomea)  in  all  earths  in  which  plants  are  found.  Ehrenberg,  in  his  Ml- 
Jcrogeohgie,  has  established  the  fact  as  a  universal  one,  and  pointed  out  the 
important  bearing  it  has  on  the  growth  of  the  soil.  Indeed,  it  is  difficult  to 
imagine  a  more  effectual  agent  in  the  transference  of  silica  from  the  waters 
to  the  solid  earth  than  the  growth  of  Diatomeae,  the  shells  of  which  are  as 
indestructible  as  their  multiplication  is  rapid.  Ehrenberg  is  of  opinion  that 
they  live  in  the  soil  as  well  as  in  water ;  and  the  constant  presence  of 
moisture  in  the  soil  renders  this  conceivable,  ^ilthough  tlie  proportion  of 
silicious  matter  dissolved  in  ordinaiy  water  is  but  small,  it  is  e\idently 
sufficient  to  supply  the  shells  of  millions  of  Diatoms  in  a  veiy  short  time  ; 
and  it  is  therefore  probable  that,  as  fast  as  it  is  extracted  from  the  water  by 
them,  it  is  dissolved  from  the  rocks  or  earths  in  contact  with  the  water,  so 
that  the  supply  never  fails." 

Mr.  Roper  has  also  suggested,  from  the  consideration  that  the  best  samples 
of  guano  contain  the  greatest  number  of  these  sUicious  skeletons,  which 
doubtless  serve  to  replace  the  large  amount  of  silica  abstracted  from  the  soil 
by  the  cereal  crops,  that  it  is  probable  that  the  deposits  of  many  of  our 
rivers  would  have  a  beneficial  efl'ect  if  applied  to  the  land ;  and  it  rests  vdth 
the  microscopist  to  point  out  the  most  favourable  localities  for  obtaining 
them.  Ehrenberg  notices  an  instance  where  this  has  been  done  in  Jutland, 
where  a  blue  sand  abounding  in  calcareous  and  sihcious  shells  is  collected, 
and  greatly  increases  the  fertility  of  the  arable  soil  to  which  it  is  aj^plied ; 
and  Prof.  Bailey  also  states  that  the  mud  of  Newhaven  harbour  is  used  as  a 
fertilizer,  and  is  found  to  contain  58*63  per  cent,  of  silica.  The  author 
last-named  has  moreover  adduced  instances  to  prove  that  the  great  fertility 
of  the  rice-fields  of  South  Carolina  is  mainly  due  to  their  richness  in  Diato- 
maceous remains.  This  notion  is  strengthened  by  the  examinations  of 
Ehrenberg,  and  by  the  commonly  observed  fact  of  the  occurrence  of  Diatomeas 
about  the  roots  of  plants,  especially  of  the  cereals,  which  demand  a  large 
supply  of  silicious  material  to  construct  their  stems. 

Dr.  Hooker  {ojy.  cit.)  contends  that  the  abundant  Diatomaceous  deposits  of 
the  South  Pole  supply  ultimately  the  means  of  existence  to  many  of  the 
smaller  denizens  of  the  ocean,  and  that  they  keep  up  that  balance  between 
the  animal  and  the  vegetable  kingdom  which  prevails  through  all  other  lati- 
tudes. He  adds  that  they  probably  piuify  the  vitiated  atmosphere,  just  as 
plants  do  in  a  more  temperate  region. 

In  the  arts,  the  remains  of  Diatomaceous  shells,  as  the  chief  ingredients  in 
certain  deposits,  are  brought  into  use  as  polishing-powder  under  the  name  of 
Tripoli,  and  also,  as  an  extremely  fine  and  pure  silicious  sand,  in  the  manu- 
facture of  porcelain.  The  powder  called  Tripoli  has  various  origins,  and 
differs  in  the  microscopic  organisms  it  contains.  Species  of  Melosira  especially 
abound — for  instance,  of  Melosira  varians.  Ehrenberg  informs  us  that  the 
Tripoli  of  Jastraba  in  Hungary  and  that  from  Cassel  resemble  each  other  in 
their  component  species. 

A  very  remarkable  application  of  a  deposit  of  Diatomeae  is  its  use  as 
an  article  of  food,  imder  the  pressure  of  want,  by  the  wretched  inhabitants  of 


OF  THE  DIATOME^.  87 

some  inhospitable  and  barren  districts  of  Europe — for  instance,  in  some 
localities  of  Lapland  and  of  Himgaiy,  and  in  other  parts  of  the  world. 
Ehrenberg  mentions  a  sort  of  earth  under  the  name  of  "  Tanah/'  eaten  in 
Samarang  and  Java,  which  overlays  some  moimtains  of  Java  at  several  places 
at  a  height  of  4000  feet.  It  is  generally  solid,  plastic,  and  sticky;  it  is 
rolled  and  diied  in  the  shape  of  small  sticks  over  a  charcoal  fire,  and  is  eaten 
as  a  delicacy.  An  examination  of  this  earth  disclosed  3  or  4  species  of 
Polygastrica  and  13  of  PhytoKtharia. 

It  has  been  attempted  to  make  the  specific  characters  of  Diatomaceous  de- 
posits of  critical  value  in  deciding  on  the  date  and  superposition  of  rocks. 
However,  the  geographical  distribution  of  these  beings  is  as  yet  insufficiently 
knoTVTi ;  and  eveiy  day  reveals  the  fact  that  species  deemed  peculiai*  to  some 
one  locality  are  to  be  foimd  in  others,  and  to  have  at  least  a  very  wide  range. 
We  have  already  quoted  some  examples  of  apparent  limited  diffusion  in  our 
remarks  on  geographical  distribution ;  it  is  therefore  not  necessary  to  illustrate 
the  subject  fui^ther  in  this  place. 

The  circumstance  that  some  one  or  two  species  seem  at  times  peculiar  to  a 
neighboui'hood,  has  encoiu'aged  antiquarians  to  seize  on  it  with  the  hope  of 
determining  the  locahty  whence  the  clay  was  procui^ed  from  which  ancient 
specimens  of  pottery  or  porcelain  were  manufactured. 

Another  practical  pm^pose  to  which  the  shells  of  Diatomece  have  been  put 
is  as  test-objects  for  microscopes,  the  penetrating  and  defining  powers  of  which 
are  measured  by  their  abihty  to  detect  and  demonstrate  the  existence  and 
natiu"e  of  certain  markings  on  the  siu'facc  of  the  silicious  epiderm — such, 
for  example,  as  the  stria3  of  PUurosigma. 

Ox    TUE    NATUEE    OF    DiATOMEiE,    AYHETHEK    AnIMALS    OE    PlAISTS VAEIOUS 

HYPOTHESES. — The  natiu-e  of  the  Diatomese  is  still  a  much-vexed  question, 
although  the  opinion  of  those  natui^alists  who  hold  them  to  be  plants — mem- 
bers of  the  great  family  of  Algte — preponderates.  Ehrenberg  assumed  their 
animal  natiu^e,  and  persuaded  himself  of  the  existence  of  a  complicated  organi- 
zation, such  as  neither  the  researches  of  others  can  confii*m  nor  analogy  sup- 
port. In  his  latest  papers  on  Organization,  he  has  insisted  most  strongly  on 
the  -apparent  successful  feeding  of  these  organisms  \vith  particles  of  coloiu' 
which  entered  A\ithin  their  interior.  These  experiments  are  not  satisfactory, 
and  have  failed  in  the  hands  of  others ;  it  is  besides  quite  clear,  that  the 
umbilicus,  at  which  he  represented  the  coloiu'-granides  to  enter,  is  no  real 
opening  in  the  lorica,  but  a  tliickening  of  its  epiderm. 

Prof.  Meneghiui,  now  many  years  ago,  penned  a  learned  treatise  to  prove 
the  animality  of  the  Diatomese  ;  but  although  he  offered  many  ingenious  argu- 
ments to  support  his  opinion,  he  did  not  succeed  in  establisliing  it.  Many  de- 
tails of  structiu'e  and  organization  and  micro-chemical  characters,  ui^gedby  him 
in  favour  of  their  animal  nature,  have  been  considerably  modified  or  entirely 
set  aside  by  subsequent  researches  ;  and  the  general  argument,  that  the  varia- 
tion fi'om  recognized  plants  is  in  many  particulars  very  marked,  has  only  a 
comparative  or  relative  force,  according  to  the  extent  of  differential  stmcture 
of  animals  which  may,  on  the  other  hypothesis,  be  set  forth  and  proved. 

The  distinguished  Itahan  naturalist  indeed  limits  his  design  in  the  treatise 
before  us  (On  the  Animal  nature  of  the  Diatomeoe,  R.  S.  1853)  to  disputing 
Kiitzing's  arguments  for  their  vegetable  nature,  saying  (p.  365),  "  Whilst 
unable  to  confirm  or  refute  the  opinions  of  Ehrenberg,  we  seem  to  have 
observed  facts  sufficient  to  disprove  those  of  Kiitzing." 

On  this  same  side  are  ranged  Eocke,  Eckhardt  (a  pupil  of  Ehrenberg),  and 
Prof.  Bailey,  who  express  thou-  inabihty  to  reconcile  some  of  the  structural 
details  and  physiological  phenomena  with  vegetable  organization.     Schlcidcn 


88  GENERAL  niSTORY  OF  THE  INPUSORIA. 

perliaps  should  also  be  reckoned  of  the  number,  since  he  remarks,  in  his  de- 
scription of  the  shield  of  a  Navlcula,  that  "such  an  artificial  and  complicated 
structure  amongst  plants  has  no  explanation,  and  is  entirely  without  signifi- 
cation. In  all  actual  plants  we  find  the  silica  present  in  quite  a  difi'erent 
form,  as  little  separate  scales  or  drops,  and  distributed  through  the  substance  of 
the  cell-wall." 

In  favour  of  the  vegetable  nature  of  the  Diatomeae,  on  the  other  hand,  the 
majority  of  the  original  observers  in  this  countrj^  unite  mth  many  of  the  most 
distinguished  natui-alists  of  the  Continent,  such  as  Kiitzing,  Siebold,  Nageli, 
Rabenhorst,  Braun,  Cohn,  Meyen,  &c.  The  last  inquirer,  so  long  ago  as  1839, 
urged  various  objections  against  the  presumed  animality  of  the  Desmidieas 
and  Diatomeae,  and  more  particularly  against  Ehrenberg's  views.  Respecting 
the  animality  of  the  Diatomeae  (Naviculacea),  he  remarks  generally — "  The 
reasons  adduced  for  such  belief  are  so  weak,  that  the  conclusions  deduced  from 
them  are  yet  for  the  most  part  very  doubtful." 

A  small  nimiber  of  natiu\alists  have  expressed  the  notion  that  the  Diatomeae 
belong  equally  to  the  animal  and  to  the  vegetable  kingdom.  M.  Thuret  may 
be  named  as  one  of  these,  since  he  has  stated  that  there  is  no  more  reason  in 
favour  of  the  one  afiinity  than  of  the  other.  Such  an  idea  is  certainly  unphilo- 
sophical;  for  it  would  cut  the  knot  instead  of  loosening  it,  by  the  assumption 
of  an  order  of  organic  beings  intermediate  between  the  animal  and  the  vege- 
table kingdom,  and  undeterminable  to  which  they  belong. 

We  will  now  proceed  to  state  the  leading  arguments  for  the  animality  of 
the  Diatomeae,  indicating  the  name  of  the  writer  suggesting  each,  so  far  as 
practicable : — 

1.  The  Diatomeae — many  species  at  least — exhibit  a  peculiar  spontaneous 
movement;  which  is  produced  by  certain  locomotive  organs. — Ehrenherg. 

2.  The  greater  part  have  in  the  middle  of  the  lateral  surface  an  opening, 
about  which  certain  roimd  corpuscles  are  situate,  which  become  coloured  blue 
when  placed  in  water  containing  indigo,  like  the  '  stbmach-ceUs'  of  many  In- 
fusoria, and  consequently  may  equally  be  regarded  as  stomachs. — Ehrenherg. 

3.  The  shells  of  many  Diatomaceae  resemble  in  structiu-e  and  conformation 
the  calcareous  shells  of  Gasteropoda  and  similar  Mollusca. — Ehrenherg. 

4.  The  method  of  multiplication  by  self- division. — EJirenhei^gandMeneghini. 

5.  The  complicated  structure  of  the  waU  of  the  frustules,  and  the  characters 
of  the  silicious  deposit. — Schleiden,  Bailey,  and  Meneghini. 

6.  The  greater  affinity  in  chemical  composition  of  the  contents  (the  endo- 
chrome)  with  animal  than  with  vegetable  products. — Meneghini. 

Each  of  these  arguments  requires  examination  in  detail,  and  its  value  tested. 
To  begin  therefore  with  the  first — the  occuiTence  of  locomotion  and  the  organs 
by  which  it  is  effected,  as  e^ddences  of  animal  constitution.  Morren,  in  the 
paper  quoted  {Jahreshericht  Akad.  Berlin,  1839),  pointed  out  that  motion  is  not 
confined  to  animals,  but  exhibited  also  by  the  spores  of  Algae  and  by  sperm- 
atic particles.  To  these  examples  may  be  added  the  Oscillatoriae,  Proto- 
coccus  in  its  various  phases,  Vaucheria  clavata,  Ulothrix  zonata,  and  other 
Algae,  among  which  are  the  now  admitted  genera  of  Yolvocineae.  In  many 
of  these,  the  movements  are  much  more  active  and  lively,  and  present  more 
seeming  spontaneity  than  those  of  any  of  the  Diatoms.  The  employment  of 
the  word  spontaneous  to  signify  the  sort  of  movement  of  these  organisms  is 
certainly  unjustifiable,  if  understood  at  all  in  its  usual  signification,  of  an  act 
originating  in  the  moving  body  directed  to  a  special  purpose  ;  for  no  more 
spontaneity  is  manifested  in  the  motions  of  these  siKcious  organisms  than  in 
those  of  the  leaves  of  the  Dionc^a  ^niiscijnda  when  any  particle  impinges  on 
their  sensitive  hairs.     Meneghini,  in  examining  this  point,  is  compelled  to 


OF  THE  DIATOME.E.  oYf 

admit  that  no  absolute  proof  is  deducible  from  the  movements  of  the  fmstules, 
in  support  of  their  animal  nature ;  and  the  only  difficulty  to  him  against 
admitting  that  they  may  be  vegetable  in  character,  is,  that  they  are  so  dif- 
ferent from  those  of  Oscillatoriae,  Desmidiese,  and  Protocoecoidese, — a  worth- 
less objection,  to  be  sufficiently  answered  by  asking  whether  that  motion  does 
not  diifer  as  widely  from  that  of  any  -animals,  and  whether  the  movements  of 
the  Desmidieee  are  not  equally  unlike  those  of  the  OscillatoriaB  as  those  of  the 
Protococciis. 

The  locomotive  organs  insisted  on — consisting,  according  to  Ehrenberg,  of  a 
retractile  foot  and  of  retractile  ciliary  processes — have  not  been  sufficiently 
demonstrated  to  use  as  an  argument.  Ehrenberg,  Corda,  and  more  lately 
Focke,  are  the  only  observers  who  pretend  to  have  seen  such  organs,  although 
the  organisms  said  to  possess  them  are  subjects  of  daily  minute  research  by 
hundreds  of  wonder-finding  microscopists.  The  mucous  film  which  invests 
many  Diatomaceous  fmstules  may,  indeed,  have  been  seen  and  misinterpreted. 
Meneghini  calls  attention  to  a  kind  of  sparkling  or  agitation — actually  a  rapid 
and  indeterminate  change  in  the  refraction  of  light  at  their  extremities,  which 
he  seems  disposed  to  believe  shadows  forth  the  presence  there  of  some  sort 
of  ciliaiy  locomotive  organs.  Granting,  however,  that  cilia  were  ascertained  to 
be  the  cause  of  the  movements  perceived,  the  doctrine  of  animality  would  in 
no  way  be  advantaged,  since  cilia  are  not  peculiarly  animal  structures. 

According  to  Nageli,  one  sort  of  vegetable  movements  originates  in  the  act 
of  growth.  Of  such  a  kind  are  probably  the  \ibrations  of  the  Oscillatoriae ;  and 
possibly  the  motions  of  the  Diatoms  are  in  some  degree  reducible  to  the  same 
category.  And  it  is  to  be  remarked  that  these  motions  are  not  equally  apparent 
and  active  under  all  circumstances,  even  among  specimens  of  the  same  species, 
but  are  most  so  when  the  vital  phenomena  of  the  organisms  are  most  aroused — 
when  the  most  rapid  interchange  of  material  is  going  on  between  the  external 
medium  and  the  internal  cavity. 

2.  The  second  argument  rests  entirely  upon  hj^^othetical  grounds,  derived 
from  Ehrenberg's  observations,  and  is  valueless  so  long  as  those  observations 
are  imconfirmed.  It  seems  quite  clear  that  the  central  opening  or  umbilicus 
spoken  of  has  no  real  existence  ;  and  if  this  be  so,  then  the  apparent  entrance 
of  coloming  matter  within  a  set  of  corpuscles  situated  around  it  must  be  an 
error  of  obsei-vation,  unless  the  unproved  and  improbable  assumption  be  made 
that  the  coloui'-particles  enter  at  foramina  placed  elsewhere  (as  at  the  extre- 
mities), and  become  transmitted  to  these  centrally  placed  sacs  or  so-called 
stomachs.  Kiitzing  declares  that  the  seeming  entrance  of  colour-granules  is 
the  result  of  mechanical  causes,  and  adds  the  more  important  statement  that 
the  central  collection  of  vesicles  is  often  wanting. 

3.  The  third  argument,  that  a  resemblance  obtains  between  the  shells  of 
Bacillaria  and  those  of  some  Molluscous  animals,  is,  to  say  the  least,  fanciful, 
and  in  a  scientific  inquiry  can  be  admitted  to  prove  nothing.  If  external 
similarity  proved  anything,  it  might  as  weU  be  adduced  to  demonstrate  the 
affinity  of  a  lead-tree  with  the  higher  plants,  whilst,  again,  the  error  to  which 
this  sort  of  proof  wiU  lead  is  well  exemplified  in  the  case  of  the  Eoraminifera, 
which  from  mere  outward  resemblance  were  for  years  accounted  members  of 
the  Cephalopodous  family.  In  the  latter  instance,  indeed,  the  similarity  in 
external  form  was  very  striking — far  exceeding  that  of  any  Diatom  with  any 
testaceous  animal. 

Kiitzing,  in  his  review  of  this  assigned  reason  for  their  animality,  meets  it 
in  another  way,  by  observing  that,  among  the  cells  of  higher  plants,  examples 
are  to  be  found  which  in  configui^ation  and  other  particulars  agree  mth  Dia- 
toms— for  instance,  the  numerous  forms  of  pollen  with  their  angles,  spines. 


90  GENERAL  HISTORY  OF  THE  INFUSORIA. 

&c.  But,  as  Menegllim  remarks,  ''  he  might  have  added  the  more  appropriate 
instance  of  the  Desmidieae,  which  would  be  very  closely  allied  to  the  Diatomege, 
if  the  latter,  like  the  former,  could  bo  referred  to  the  vegetable  kingdom.  If 
not  equal  in  constancy  and  regularity,  the  Desmidieae  display  a  greater  degree 
of  complication:  and  we  must  remember  the  different  nature  of  their  substance; 
for  in  the  vegetable  cell,  when  lime  or  silica  predominates,  the  wall  becomes 
imiform  and  regular." 

4.  Multiplication  by  self-division  was  at  one  time  cited  by  Ehrenberg  as 
peculiarly  an  animal  phenomenon, — a  notion  at  variance  Avith  the  observations 
of  every  naturalist,  and  now  requiring  no  refutation.  However,  Meneghini 
has  more  recently  advanced  the  statement  that  an  essential  difference  in  the 
process  of  fission  prevails  between  the  Diatomeae  on  the  one  hand  and  the 
Desmidieae  and  Algae  in  general  on  the  other,  applying  to  the  former  modifi- 
cation (in  accordance  "with  Brebisson's  views)  the  term  deduplication,  to  the 
latter  reduplication.  To  extract  his  remarks  {op.  cit.  368) — "  Division  is 
always  longitudinal,  and  takes  place  underneath  a  fine  external  sihcious 
membrane,  by  the  formation  of  contiguous  diaphragm  walls  which  divide  the 
internal  ca\T.ty.  Thus  the  contents  are  longitudinally  divided ;  and  this  divi- 
sion is  complete  if  the  two  new  individuals  detach  themselves  and  so  acquii^e 
individual  liberty.  It  is  imperfect  if  the  fine  silicious  persistent  membrane 
and  the  secreted  gelatinous  substance  retain  them  connected  together.  This 
mode  of  reproduction  (which  Brebisson  distinguished  by  the  name  of  dupli- 
cation and  deduplication,  from  the  reduplication  of  Desmidieae)  deserves  the 
most  attentive  observation.  The  foregoing  exposition  presents  the  fact  in  its 
most  rude  and  superficial  general  appearance,  and  makes  us  feel  acutely  the 
want  of  a  more  ciix'iunstantial  description  peculiar  to  various  forms.  It  is 
only  after  having  established  facts  relative  at  least  to  the  principal  generic 
tj-pes,  that  we  can  establish,  on  a  scientific  basis,  the  general  idea  of  multi- 
plication by  duphcation.  A  few  observations  suffice,  however,  to  prove  that 
this  does  not  occur  in  so  simple  a  manner  as  we  are  taught  to  believe,  by 
compaiing  it  with  that  in  vegetable  cells.  In  the  Achnanthidia,  for  example, 
it  is  described  and  figured  that  the  principal  surfaces,  which  occupy  the  inter- 
mediate space  between  the  two  superior  and  the  inferior  valves,  commence  by 
presenting  fine  transverse  lines,  and  next  a  strong  longitudinal  line  along  the 
middle ;  then  there  appear  two  new  intermediate  valves  contiguous  to  each 
other — the  superior  valve  (?)  of  the  new  inferior  individual,  and  the  inferior 
one  of  the  superior.  My  observations  convince  me  that  the  affair  does  not 
proceed  vsith  so  much  simpUcity.  I  have  often  seen  the  two  lateral  valves 
separated,  and  the  intermediate  space  thus  largely  amplified.  In  other  cases 
there  appeared  only  a  new  inferior  valve  complementary  to  the  superior,  the 
inferior  individual  thus  remaining  incomplete.  Finally,  in  others,  between 
the  complete  superior  individual  and  the  incomplete  inferior  valve,  there 
appeared  a  new  individual  with  both  its  valves,  but  nearer  together,  smaller, 
finer,  with  lines  much  less  distinct."  In  short,  "  in  this  phenomenon  there 
is  more  complication  than  that  of  a  simple  cellular  deduplication." 

5.  In  a  previous  page  (p.  88)  we  have  quoted  Schleiden's  notice  of  a  dif- 
ficulty in  the  way  of  recognizing  Diatoms  to  be  plants.  It  is  one  likewise 
which  has  presented  itself  to  others,  for  instance,  to  Prof.  Bailey  and  Mene- 
ghini. ^'  If  we  suppose  them  to  be  plants,"  says  the  latter  writer,  "  we  must 
admit  every  frustule,  every  Navicida,  to  be  a  cell.  We  must  suppose  this  cell 
with  walls  penetrated  by  silica  dev'eloped  within  another  ceU  of  a  different 
nature,  at  least  in  every  case  where  there  is  a  distinct  pedicle  or  investing 
tube.  In  this  silicious  waU  we  must  recognize  a  complication  certainly  im- 
equalled  in  the  vegetable  kingdom."  (op.,  cit.  p.  372.) 


OF  THE  DIATOMEiE.  ~  91 

This  critique  of  Meneghini  loses  much  of  its  force  when  it  is  noticed  that 
the  existence  of  a  pedicle,  or  isthmus,  or  of  a  muco-gelatinous  sheath  envelop- 
ing the  frustules,  is  assumed  by  him,  quite  h}^:)othetically,  to  indicate  their 
formation  within  a  cell-wall  represented  by  the  soft  investment, — an  idea 
originated  by  him  because  he  could  not  admit  of  an  extra-cellular  formation. 
The  present  state  of  knowledge,  however,  clearly  recognizes  the  not  infi-equent 
formation  of  extra- cellular  matters  about  cells,  and  consequently  this  portion 
of  the  difficidty  in  question  will  cease  to  have  importance. 

On  the  other  hand,  no  animals  can  be  pointed  out  having  a  similar  complex 
silicious  stmetiu'e,  whilst  an  analogy  may  be,  to  a  certain  extent,  foimd  with 
the  Desmidiea),  some  of  which  have  a  small  deposit  of  silica  in  their  envelopes, 
which  again  in  some  Diatomaceous  frustules  is  very  deficient  (see  p.  37). 

Indeed,  the  affinity  between  the  Dcsmidiese  and  the  Diatomea)  is  manifested 
by  the  diffferential  characters  vrhich  naturalists  feel  themselves  called  upon  to 
indicate  (see  p.  95). 

The  composite  structure  of  the  fnistules  is  principally  the  residt  of  the  per- 
meation of  the  external  timic  with  silex.  The  little  box  or  capsule,  when 
first  produced,  represents  a  simple  enclosed  cell,  imbued  with  more  silica  than 
a  Desmidiaceous  frond,  but  otherwise  not  histologically  unlike.  When  the 
Httle  being  prepares  for  self-di\'ision,  the  opposite  valves  separate,  much  as 
the  opposed  halves  of  a  frond  of  one  of  the  Desmidiea?,  and  the  intermediate 
production,  according  to  the  habit  of  the  class,  becomes  penetrated  by  silica 
(to  a  less  extent,  however,  than  the  original  valves),  and  assumes  so  much  of 
a  permanent  character  that  it  is  very  frequently  considered  an  independent 
tliii'd  segment. 

So  again,  the  cellular,  or  areolate,  or  otherwise  figured  and  involuted  sui-face 
of  the  frustules,  cited  by  Meneghini  as  dissimilar  to  any  plant- structure,  would 
also  ajjpear  to  be  a  consequence  of  this  permeation  of  the  organic  membrane 
with  silica,  and  of  various  modifications  consequent  thereon.  To  show  that 
analogies  are  not  wanting  in  the  vegetable  kingdom  of  ciuiously  modified  and 
figured  cell-waUs,  we  may  mention  as  examples,  besides  poUen-grains,  in- 
stanced by  Kiitzing,  the  sporangia  of  Desmidiea?  and  of  various  Algae.  More- 
over, the  capability  of  the  simplest  enclosing  membrane  to  develope  a  very 
complex  superficial  structm^e  is  illustrated  in  the  case  of  the  Rhizopodes, 
among  which  are  many  examples  of  striated,  areolated,  and  other-wise  modified 
shells,  which,  in  the  eyes  of  many,  range  "with  imiceUular  organisms.  We 
must  not  forget  to  state  that  Meneghini  himself  seems  to  have  appreciated 
the  eff'ect  of  the  permeation  of  silica  upon  the  characters  of  the  ceU-wall ;  for 
he  says,  in  liis  supplementary  annotations  {op.  cit.  p.  511),  "  the  part  which 
sHex  takes  in  the  formation  of  the  cell- wall  is  undeniable,"  as  in  the  epi- 
dermis of  Gramineae,  Palms,  and  Equiseta.  "  The  stomatic  cells  of  Equiseta 
merit  particular  attention,  both  fi'om  the  silex  they  contain,  and  the  transverse 
striae  they  present  on  the  internal  surface.  This  resemblance  to  the  shield  af 
Diatomeae  might  lead  us  to  believe  that  we  ought  to  regard  it  as  an  argument 
for  maintaining  the  vegetability  of  the  latter:  but  I  do  not  think  that  I  ought 
to  dwell  upon  such  an  objection  ;  I  only  notice  it  because  I  would  not  appear 
to  be,  or  pretend  to  be,  unacquainted  with  it.  Yet  it  seems  to  mo  important  in 
another  point  of  view — the  apparent  complication  that  the  simple  cell  may 
assume  when  penetrated  by  silica." 

We  cannot  do  better  than  close  this  part  of  the  argument  by  Prof.  Smith's 
review  of  the  subject  (Si/noj^s.  ii.  p.  xix) : — ''  In  every  case  this  membrane 
[of  the  frustule]  is  more  or  less  penetrated  or  imbued  with  silex;  and  the 
presence  of  this  substance  appears  to  have  modified  the  intimate  structiu^e  of 
the  membrane,  and  induced  great  variety  in  the  mode  and  character  of  its 


92  GENEKAL  HISTORY  OF  THE  INFUSOEIA. 

formation  in  different  genera,  accompanied  by  great  regularity  in  the  indi- 
vidual species. 

"  These  variations  exhibit  themselves  in  the  different  modifications  of 
structure  which  constitute  the  markings  of  the  valves,  aj^pearing  imder  the 
form  of  ribs  and  nodules,  costae,  striae,  or  cellules  of  an  elliptical,  circular, 
or  hexagonal  outline.  A  wide  comparison  of  specimens  seems  to  me  to  prove 
that  these  various  markings  originate  in  the  tendency  impressed  upon  all 
organized  structm-e  to  develope  itself  upon  the  type  of  the  cell,  and  that  the 
presence  of  the  silicious  constituent  in  the  cell-membrane  of  the  Diatom  gives 
a  fixedness  to  this  tendency,  which,  in  ordinary  cases,  is  either  not  discern- 
ible in  the  structure  of  the  membrane,  or  whose  effect  is  obliterated  by  the 
coalescence  of  the  softer  material  which  constitutes  its  substance.  However 
this  may  be,  it  ajipears  to  me  certain  that  the  structure  of  the  silicious  valve 
in  the  Diatomaceae  is  invariably  cellulate,  the  cellules  being  more  or  less 
modified  according  to  the  peculiar  requirements  of  each  species,  and  that  no 
other  explanation  of  their  characteristic  markings  seems  consistent  with  the 
facts  which  are  established  by  a  carefiil  examination  and  comprehensive  know- 
ledge of  Diatomaceous  structure.  That  this  explanation  does  not  involve  con- 
siderations at  variance  wdth  the  conditions  of  unicellular  vegetable  life,  will 
be  ob\ious  to  any  one  familiar  with  the  stnicture  of  the  sihcious  epiderm  in 
the  Equisetaceae  and  Graminaceae,  and  the  distinctly  cellulate  structui'e  of 
many  pollen-grains,  while  this  very  presence  of  silex  as  a  constituent  of  the 
cell-wall  in  the  Diatomaceae  appears  to  be  wholly  unaccoimtable  except  on  the 
supposition  of  the  vegetable  nature  of  these  organisms.  In  no  instance  do  we 
find  a  parallel  condition  in  the  animal  kingdom  (for  the  secretion  of  silicious 
spicula,  as  an  mtemal  skeleton,  in  some  of  the  Spongideae,  cannot  be  regarded 
as  an  analogous  phenomenon),  whereas  the  vegetable  kingdom  furnishes  us 
with  cases,  not  merely  of  the  secretion  of  silex  as  a  vegetable  product  in  the 
Bamboo,  but  with  frequent  instances  of  its  intimate  union  with  cellulose  in 
the  membrane  which  forms  the  epiderm  of  the  cell,  as  in  the  Natural  Orders 
abeady  mentioned,  in  the  Palmaceae  and  others." 

On  the  nature  and  mode  of  deposition  of  the  silex.  Dr.  Bailey  has  ad- 
vanced the  statement  that  the  silica  in  Phytolitharia,  as  well  as  in  Diatomeae, 
Polycystineae,  and  Spongilithes,  is  not  doubly  refi'active  and  polarizing,  as 
Ehrenberg  described,  and  that  even  the  adniitted  exception  of  AracJinoi- 
discus  is  not  such.  The  error  in  supposing  it  so  has  originated  from  the  im- 
perfect removal  of  the  dense  carbonaceous  tissues  which  are  deposited  beneath 
the  silica. 

6.  The  final  argument  we  have  to  consider  for  the  animality  of  the 
Diatomeae  is,  that  the  greater  affinity  in  the  chemical  composition  of  the 
contents,  i.  e.  of  the  endochrome  or  gonimic  substance,  is  with  j)lants,  and  not 
with  animals.  This  argument  is  certainly  based  on  a  nice  and  very  drfiicult- 
tb-be-determined  fact.  Meneghini  insists  on  it  as  important.  His  remarks 
have  already  been  given  in  om-  notice  of  the  contents  of  the  frustules,  to 
which  we  must  refer  (p.  47),  adding  here  only  some  supplementaiy  obser- 
vations to  fully  convey  his  opinions.  ''  Finally,"  he  Avrites  {op.  cit.  p.  366), 
for  this  is  not  a  property  peculiar  to  chloroj)hyll,  "  I  may  add  that,  if  a  portion 
of  chlorophyll  could  be  demonstrated  in  the  interior  of  Diatomeae,  this  would 
by  no  means  mvalidate  their  animal  nature ;  we  might  still  suppose  they  had 
swallowed  it  for  food.  As  to  the  oil-globules  "  w^hich  Kiitzing  represents, 
Meneghini  considers  they  may  be  no  more  than  particles  of  sarcode,  which 
have  an  oily  appearance  ;  and  he  would  observe  ''  that  the  number  and  volume 
of  these  globides  increase  considerably  after  death,  and  that  during  life  they 
are  situated  upon  a  longitudinal  line  extending  from  one  extremity  to  the 


OF  THE  DIATOME.E.  &3 

other.  And,"  he  continues,  ''  I  rely  upon  the  observation  that  there  is  some 
motion  and  successive  alteration  in  them,  as  if  these  minute  globules  mixed 
with  larger  ones,  and  separated  again  from  them."  For,  to  the  mind  of 
the  Italian  naturalist,  the  hypothesis  of  stomachs  is  admissible,  although 
the  fact  that  a  polygastric  structure  (affirmed  by  Ehrenberg)  has  not  been 
shown  in  the  ciliated  Protozoa  is  in  itself  an  a  priori  argument  that  such  an 
organization  is  not  to  be  found  in  the  Diatomeae,  among  which  animal  cha- 
racteristics are  so  much  more  deficient  and  indeterminate. 

Although,  to  our  apprehension,  this  argument,  based  on  the  diiferential 
chemical  composition,  to  the  extent  it  is  developed  by  Meneghini,  is  incom- 
plete and  inconclusive,  yet  it  was  a  duty  to  present  it,  in  order  that  some  of 
the  many  ardent  English  microscopists  may  be  induced  to  attempt  the  solution 
of  this  micro-chemical  question. 

Rabenhorst,  we  should  not  omit  to  state,  describes  the  colouring  matter  of 
Diatomca?  as  quite  different  from  the  chlorophyll  of  plants.  For  instance,  he 
states  that  the  chlorophyll  of  plants  is  taken  up  by  alcohol,  dissolves  with  a 
yellowdsh-green  colour  in  alkalies,  and  with  muriatic  acid  acquii'es  an  emerald- 
green  colour,  whereas  the  coloming  material  of  Diatomece  is  insoluble  in 
alcohol  (although  after  a  time  its  coloiu"  fades),  remains  unchanged  by  alkalies, 
and  acquires  a  pale-green  colour  mth  muriatic  acid. 

It  still  remains  to  point  out  the  facts  which  speak  in  favom'  of  the  vegetable 
nature  of  the  Diatomacese.  The  following  summary  was  offered  by  Kiitzing : — 

"  1.  The  great  resemblance  of  compound  forms  to  xilgse,  and  their  develop- 
ment by  fission.  There  are,  indeed,  compound  Infusoria,  as  Monad-masses 
and  Polypes  :  but  the  former  are  very  questionable  animals ;  and  the  latter 
have  this  essential  distinction,  that  the  individual  animal  lives  without 
(external  to)  its  habitation,  and  moves  freely,  whereas  such  Naviculce  as 
Encyonema,  Scliizonema,  and  Micromega,  and  similar  genera,  grow  within  the 
enclosing  substance,  building  themselves  up  like  the  cells  in  the  stem  of  a 
plant — so  vegetating  here  only  as  cells.  In  like  manner,  the  individuals  of 
Fragilaria,  Melosira,  Himantidium,  &c.,  are  steadily  fixed,  and  unable  to 
exhibit  animal  motion. 

"2.  The  inner  soft  organic  parts,  which  I  have  designated  gonimic  sub- 
stance, possess,  as  well  in  their  chemical  nature  as  in  theii'  development, 
peculiarities  akin  to  those  met  T\dth  in  the  ceU- contents  of  confervoid  Alg^e. 

*'  This  relation  is  most  clearly  seen  in  the  genus  Melosira  and  its  allied  forms, 
which,  not  only  in  form,  but  also  in  the  chemical  components  of  their  con- 
tained matter  (since  the  presence  of  chlorophyll  is  common  to  all  Diatomea?), 
are  closely  allied  to  the  confervoid  Algae. 

"  3.  The  development  of  seeds,  or  young  [as  Kiitzing  represents  it],  occurs 
here  as  in  undoubted  Algae,  but  never  as  in  true  animals. 

"  4.  The  Diatomeae,  and  especially  the  free  moving  Naviculce,  develope,  in 
the  sun's  rays,  an  appreciable  quantity  of  oxygen,  like  all  admitted  plants. 

"  The  evolution  of  oxygen,  indeed,  occurs  in  green  Monads  and  Euglence ; 
but  this  affords  no  argument  for  the  animality  of  the  Diatomeae,  but  renders 
the  animal  nature  of  those  Infasoria  themselves  veiy  doubtfirl,  and  the  more 
so  as  recent  observations  confirm  the  idea  of  the  origin  of  the  lower  plants 
themselves  from  Monads  and  Euglence.  AVherefore  all  these  comparisons 
serve  to  favour  the  belief  in  the  vegetable  nature  of  Diatomeae." 

To  these  arguments  has  been  added  another,  resting  on  the  assumption  of 
conjugation  being  peculiar  to  plants ;  and  Mr.  Blackwell  chscovers  further 
evidence  of  plant-life  in  the  variations  of  form  of  the  fmstules  of  the  same 
species  (J.  M.  S.  1853,  i.  p.  247). 

It  is  necessary  to  inquire,  seriatim,  into  the  real  value  of  the  arguments 


94  GENERAL  HISTORY  OF  THE  INFUSORIA. 

on  this,  as  has  been  clone  with  those  on  the  other  side  of  the  question . 
Meneghini  enters  the  lists  with  Kiitzing,  and  disputes  the  conclusions  arrived 
at  by  him,  rather  than  the  facts  on  which  they  rest. 

The  first  argument,  founded  on  external  resemblance,  has  little  value,  and 
offers  no  certain  indications  of  affinities.  However,  taking  Kiitzing' s  state- 
ments in  his  own  words,  modem  research  has  added  to  its  weight ;  for  it 
has  proved,  what  was  before  only  a  probability,  that  the  so-called  Monad- 
masses  are  only  of  a  vegetable  nature. 

The  second  reason  advanced  has  been  already  discussed,  whilst  the  thii'd 
rests  as  yet  on  incomplete  observations,  and  in  Meneghini' s  opinion  has  an 
equally  strong  analogy  in  animals,  for  example,  "  in  the  ovaries  of  PoIj^dcs 
and  other  inferior  animals,  as  in  many  0\ipara  of  superior  classes.  And,  in 
fact,  the  bag  of  a  spider,  with  the  thousands  of  small  eggs  that  it  contains, 
seems  to  me  quite  as  like,  as  the  spore  of  an  Alga,  to  the  organ  of  propaga- 
tion of  a  Scliizonema  or  a  Micromccja.''^  These  analogies  cannot  be  allowed 
much  weight,  whilst  it  is,  on  the  contrary,  pretty  clearly  ascertained  that  the 
sporangia  of  Diatomeae  produce  a  brood  of  young  forms  within  them, — a 
phenomenon  according  in  all  particulars  with  the  mode  of  reproduction  in 
numerous  Algae  and  Fungi. 

The  foui^th  argument  for  their  vegetable  nature  must  be  admitted  to  possess 
great  importance.  Since  Kiitzing  enunciated  it,  the  apparent  objections 
against  the  vital  phenomena  in  question  being  restricted  to  plants,  have  been 
removed  by  subsequent  inquiry.  The  green  Monads  and  Euglence,  cited  by 
Kiitzing,  are  now  recognized  to  be  vegetable,  and  can  no  longer  east  doubt,  by 
reason  of  an  assumed  animal  nature,  on  the  fact  of  the  evolution  of  oxygen 
being  a  characteristic  of  vegetable  life.  The  evolution  of  oxygen,  as  Prof. 
Smith,  like  every  other  careful  observer,  tells  us,  "  may  be  noticed  in  any 
mass  of  Diatomacea3  during  the  warmer  months  of  the  year,  or  in  gatherings 
freely  exposed  to  the  sun,  in  the  elevated  temperature  of  a  confined  apartment, 
during  the  winter  or  spring.  Under  these  conditions  the  water  in  the  vessel 
becomes  covered  with  mmute  bubbles  of  oxygen,  and  portions  of  the  Diato- 
maceous  stratum  are  floated  up  by  the  buoyancy  of  the  globules  of  this  gas 
adhering  to  their  frustules.  Such  phenomena  can  only  be  accounted  for  by 
supposing  that  the  Diatomaceae  are  plants,  and  that  they  exhale,  like  all 
plants  in  a  state  of  active  vegetation,  oxygen  from  their  tissues  ;  but  this  pro- 
cess is  iiTeconcilablc  with  the  hypothesis  of  their  animal  nature."  (Si/noj)s. 
vol.  ii.  p.  XX.) 

Prof.  Carpenter  insists  {Microscope,  p.  469),  that  the  most  positive  and 
easily  defined  distinction  between  Protophyta  and  Protozoa  "lies  in  the 
nature  of  the  aliment,  and  in  the  method  of  its  introduction,"  in  each  case. 
"  For  whilst  the  Protophyte  obtains  the  materials  of  its  nutrition  from  the 
air  and  moisture  that  surround  it,  and  possesses  the  power  of  detaching 
oxj'gen,  hydrogen,  carbon,  and  nitrogen  from  their  previous  binary  combina- 
tions, and  of  uniting  them  into  ternary  and  quaternary  organic  compounds 
(chlorophyll,  starch,  albumen,  <S:c.),  the  simplest  Protozoon,  in  common  with 
the  highest  members  of  the  animal  kingdom,  seems  utterly  destitute  of  any 
such  power,  and  is  dependent  for  its  support  upon  organic  substances  pre- 
viously elaborated  by  other  beings.  But  further,  the  Protophyte  obtains  its 
nutriment  by  mere  absorption  of  liquid  and  gaseous  molecules,  which  pene- 
trate by  simple  imbibition,  whilst  the  Protozoon,  though  destitute  of  any 
proper  stomach,  makes  (so  to  speak)  a  stomach  for  itself  in  the  substance  of 
its  body,  into  which  it  ingests  the  solid  particles  that  constitute  its  food,  and 
within  which  it  subjects  them  to  a  regular  process  of  digestion.  Hence  the 
simplest  members  of  the  two  kingdoms,  which  can  scarcely  be  distinguished 


OF  THE  DIATOME.E.  95 

from  each  other  by  any  structural  characters,  seem  to  be  j^hysiohgicaUi/  sepa- 
rable by  the  mode  in  which  they  perform  those  actions  wherein  their  life  most 
essentially  consists." 

The  process  of  conjngation  has  been  used  as  an  argument  for  the  vegetable 
natiu-e  of  Diatomeae  by  Mr.  Thwaites  and  others.  This  subsequently  seemed 
to  be  set  aside  by  the  observation  of  apparent  conjugation  in  Act'mophrys  and 
Oregarina  observed  by  Kolliker  and  Cohn.  However,  this  phenomenon 
appears  again  in  the  ascendant  as  a  vegetable  characteristic ;  for  the  observa- 
tions of  Mr.  Weston  {J.  M.  S.  1856,  122),  of  Leuckart,  Lieberkuhn,  and 
others,  go  to  show  that  the  act  believed  to  be  one  of  conjugation  in  the 
Actinoj)Jiri/s,  is  not  really  a  process  of  reproduction,  but  merely  a  temporary 
cohesion :  moreover  Lieberkuhn  (Mem.  de  VAmd.  Roy.  Belgique,  vol.  xvi.) 
proves  that  the  production  of  the  Navkellce  is  not  necessarily  a  consequence 
of  the  act  of  conjugation  in  the  Gregarince. 

If  futm-e  research  substantiate  the  fact  that  conjugation  is  essentially  a 
vegetable  process,  then  the  nature  of  the  Diatomeos  will  no  longer  be  doubtful. 

On  a  review  of  the  arguments  ui^ged  on  each  side,  and  on  consideration  of 
the  whole  structural  and  vital  peculiarities  of  the  Diatomese,  we  are  disposed 
to  consider  them  of  a  vegetable  nature — members  of  the  great  family  of 
Algse,  and,  together  with  many  other  unicellular  plants,  to  constitute  a  group 
known  by  the  name  of  Protophyta.  Nageli,  in  1849,  took  this  view,  and 
reckoned  the  Diatomeae  as  one  of  his  eight  orders  of  unicellular  Algse,  of 
which  the  Desmidiaceos  and  Palmellaceae  were  other  two.  How  close  must 
be  the  affinity  of  the  Diatomese  with  the  Desmidieas  is  shown  by  the  fact  of 
the  two  families  ha\ing  so  long  been  treated  of  together  under  the  common 
head  and  name  of  Bacillaria.  And  although  sufficiently  decisive  characters 
separate  the  one  set  of  beings  from  the  other,  yet,  in  the  grand  phenomena 
of  hfe  and  organization,  a  true  homology  exists.  The  difference  between  some 
Desmidiese  and  Palmellese  is  as  much  pronounced  as  it  is  between  the  former 
and  some  Diatomea) ;  and  between  these  several  orders,  together  with  the 
Zygnematse,  various  intermediate  forms  are  to  be  found,  which  serve  as  con- 
necting links.  Although  Mr.  Ralfs  would  not  now  insist  upon  the  distinc- 
tions between  the  Desmidieae  and  Diatomeae,  formerly  laid  down  by  him  as 
decisive,  yet  they  may  be  here  reproduced  with  advantage.  1.  In  Diatomeae 
(op.  cit.  p.  19)  "  each  frustule  consists  of  three  pieces,  one  central,  ring-like 
and  continuous  all  romid,  and  the  others  lateral."  In  opposition.  Prof.  Smitli 
asserts  that  the  central  third  segment  is  no  essential  part  of  the  frustules, 
but  a  portion  produced,  just  like  that  between  the  opposed  valves  of 
Desmidieae,  preparatory  to  the  process  of  self-fission.  2.  ''  The  division  is 
completed  by  the  formation  of  new  portions  within  the  enlarged  central 
piece,  which  then  falls  off,  or  else  by  a  new  septum  arising  at  the  centre;" 
but  Mr.  Ralfs  believes  that  in  every  case  the  separation  commences  internally 
before  it  extends  to  the  covering.  So  far  as  we  can  understand  the  matter, 
no  essential  variation  in  this  process  prevails  in  the  two  families.  3.  "  Their 
coverings,  with  very  few  exceptions,  are  sihcious,  withstand  the  action  of 
fu-e  and  acids,  and  may  be  broken,  but  not  bent ;  the  frustules  are  often 
rectangular  in  form,  are  never  warted,  and  scarcely  ever  spinous."  To  these 
statements  it  may  be  replied,  that  in  a  few  Diatoms  the  silex  is  in  small 
quantities  in  the  valves,  and  that,  on  the  contraiy,  examples  of  partially 
sihcious  Desmidieae  are  known.  The  action  of  fire  and  acids,  the  capability 
of  being  bent  or  not,  are  qualities  dependent  on  the  relative  proportion  of 
silex  in  the  frustules,  and  are  but  secondary  chstinctions.  The  same  may  be 
said  of  the  remaining  points  mentioned — the  rectangular  form,  and  the 
presence  of  warts  and  spines.     The  form  indeed  is,  at  best,  of  little  value  in 


96  GENERAL  HISTOKY  OF  THE  INFUSOP.IA, 

the  argument.  The  rectangular  form  of  the  Diatomeae  is  doubtless  a  conse- 
quence mainly  of  the  silicious  composition :  yet  it  is  far  from  univei^al  among 
them ;  for  some  species  are  rather  orbicular,  others  sections  of  cylinders,  others 
capsular,  and  others  again  not  unhke  square  sacs  with  bulging  sides  and  rounded 
corners.  Even  where  a  rectangular  outline  exists,  it  is  most  frequently  only  in 
one  view  ;  and  the  most  that  can  be  said  is,  that  the  Hues  of  junction  are  in 
many  instances  acute.  On  the  other  hand,  examples  of  a  rectangular  outline 
are  to  be  found  among  the  Desmidieae  and  their  allies  :  the  junction-surfaces 
of  Hyalotheca  and  Didymoprium  are  at  right  angles  to  the  sides  of  the  frond ; 
the  end  view  of  Staurastrmn  tumiduin  is  as  angular  as  the  front  \iew  of  a 
Triceratium ;  and  the  front  view  of  Euastrum  euneatum  presents  decidedly 
rectangular  truncate  extremities.  So  too  in  the  genus  Pediastrum,  formerly 
enumerated  among  the  Desmidieae,  although  now  detached  as  a  subfamily 
and  placed  between  them  and  the  Palmelleae,  examples  of  an  angular  outline 
occur,  as  in  the  Pediastrum  Tetras  and  other  species.  As  to  the  production 
of  spines,  sufficiently  numerous  examples  exist  among  the  Diatomeae  to  prove 
it  no  distinctive  peculiarity  of  the  Desmidieae ;  and  although  warty  expan- 
sions or  elevations  of  the  surface  precisely  like  those  of  some  Desmidieae,  may 
not  be  noticed  in  Diatomeae,  yet  certain  exaggerated  inflations  of  the  surface 
are  seen  in  some  Diatomeae,  e.  g.  in  Biddidpliia  pidcheUa  and  B.  regina. 
The  two  next  distinctions  indicated  by  Mr.  Ralfs  are  of  more  consequence, 
but  nevertheless  cannot  be  admitted  as  demonstrative  of  an  entire  difference 
in  nature.  They  are  thus  stated : — ''  Their  internal  matter  is  usually  brown 
when  recent ;  and  although  some  species  are  greenish,  or  become  green  after 
they  have  been  gathered,  none  are  of  a  truly  herbaceous  character.  Their 
vesicles  bear  some  resemblance  to  those  in  the  Desmidieae ;  but  they  are 
of  a  yellower  colour,  and  no  starch  has  been  detected  in  them."  The  last 
section  of  this  statement  must  be  held  as  still  sid)  judice ;  the  chemistry  of 
the  endochrome  is  too  imperfect  to  afford  a  safe  argument,  and  the  chemical 
relations  of  starch  and  isomeric  compounds  too  little  understood.  The  con- 
cluding distinction,  "  that  the  Diatomeae  do  not  conjugate,"  the  researches  of 
Mr.  Thwaites  have  negatived. 

To  employ  the  summary  of  the  affinities  of  the  Diatomeae  presented  by 
Prof.  Smith  {Synops.  vol.  ii.  p.  xxi)  : — ''  The  Diatomaceae,  with  specialities  of 
their  owti,  have  also  intimate  alliances  with  the  other  orders  of  the  Proto- 
phyta,  resembling  the  Zygnemaceae  and  Desmidiaceae  in  the  reproductive  pro- 
cess,— the  Nostochaceae  in  the  tendency  sho^Ti  by  several  genera  to  surround 
their  frustules  with  frondose  masses  of  mucus,  within  which  linear  series  of 
cells  are  subsequently  developed, — the  Oscillatorieae  in  their  movements, — the 
Palmellaceae  and  all  the  orders  I  have  named,  in  the  self-dividing  act  by 
which  the  indi\iduals  of  the  species  are  multipHed,  or  the  aggregate  of  spe- 
cific life  maintained  and  increased." 

Deteemination  of  Species  and  Genera  ;  Varieties  ;  Classification. — 
The  question  has  been  very  much  discussed  of  late,  what  characters  of  the 
frustules  and  of  their  contents  are  to  be  employed  in  the  construction  of 
species  ?  Ehrenberg  generally  proceeded  on  the  principle  of  notifying  every 
departure  from  any  one  form,  assumed  to  be  specific,  as  representing  another 
species  ;  but  this  loose  plan  has  been  found  productive  of  error  and  of  ex- 
cessive multiplication  of  species,  inasmuch  as  shape,  or  outline,  or  markings  of 
the  surface  are  not  nearly  so  permanent  and  distinctive  as  formerly  imagined. 

Although  in  some  species  the  size  and  figure  seem  pretty  constant,  yet  in 
many  they  are  subject  to  endless  variations.  Prof.  Gregory  cites  as  examples 
of  changeableness  of  form  the  three  species,  Eunotia  gihha,  Pinnularia 
divergeyis,  and  Himantidmm  bkJens ;  and  he  would  comprehend  several  pre- 


I 


OF  THE  DIATOME^.  97 

Slimed  species  of  Navicidm  under  the  name  of  N.  varians.  So  again  Dr. 
Greville,  speaking-  {A.  N.  H.  1855,  p.  258)  of  the  Grammatopliora  (?)  Bal- 
fouriana  (Smith),  which  he  erects  into  a  new  genus  Diatomella,  observes, 
*'  There  is  greater  variation  in  the  rehitive  length  and  breadth  of  the  fnistules 
than  would  be  likely  to  occiu-  in  other  Diatomaceous  grouj)s.  In  some  the 
length  is  more  than  equal  to  twice  the  breadth,  while  others  are  exactly- 
square  ;  and  between  these  two  extremes  every  gradation  may  be  observed  ; 
resembling  in  this  inequality  Fmgilaria,  Odontidium,  Grammatopliora,  and 
other  filamentous  genera  having  piano- compressed  frustules."  But  in  this 
very  case  a  difference  arises  between  Dr.  Gre\ille  and  Mr.  Smith  respecting 
the  value  of  internal  marldngs  as  a  characteristic  distinction  ;  for  the  latter 
author  remarks,  ''  The  absence  of  a  curve  in  its  septa,  relied  upon  by  Dr. 
Greville,  I  cannot  regard  as  of  sufficient  importance  to  constitute  a  generic 
distinction,  as  this  featui'e  is  scarcely  noticeable  in  some  states  of  Gramma- 
tophora  macihnta,  and  is  imiformly  absent  in  G.  strktaj^  (Synojms,  vol.  ii. 
p.  44.) 

"  The  size  of  the  matui^e  frustule  "  (says  Prof.  Smith,  J.  M.  S.  1855,  p.  132) 
"before  self-di\asion  commences,  is,  however,  dependent  upon  the  idiosyncrasy 
of  the  embryo,  or  upon  the  cii'cumstances  in  which  its  embryonic  growth 
takes  place ;  consequently  a  very  conspicuous  diversity  in  their  relative 
magnitudes  may  be  usually  noticed  in  any  large  aggregation  of  individuals, 
or  in  the  same  species  collected  in  different  localities. 

"  It  may  also  be  easily  conceived  that,  while  a  typical  outline  of  its  cell 
must  be  the  characteristic  of  a  certain  species,  such  outline  may  to  some 
extent  be  modified  by  the  accidental  circumstances  which  suiTOund  the  em- 
bryo during  its  earlier  growth  and  development.  A  lanceolate  form  may 
become  linear,  elliptical,  or  even  somewhat  oval,  by  the  pressure  of  siuTound- 
ing  cells ;  and  acute  ends  may  be  transformed  into  obtuse  or  rounded  ex- 
tremities. 

"  Those  who  understand  the  process  of  self- division  will  see  here  a  suffi- 
cient reason  for  the  occurrence  of  multitudes  of  frustules  deviating  from  the 
normal  form,  or  even  for  the  existence  of  myriads  at  one  spot,  all  having  a 
form  different  from  the  type,- — the  single  embryo  from  which  they  have  all 
sprung  by  self- division  (which  process  stereotj^es  the  shape  with  which  it 
commences)  having  from  some  accidental  circumstances  become  modified  in 
its  outline. 

"  It  follows,  then,  from  these  considerations,  that  neither  size  nor  outline 
is  sufficient  to  enable  the  observer  to  determine  the  species  of  a  Diatoma- 
ceous frustule.  If  he  has  the  means  of  comparing  specimens  in  sufficient 
numbers  and  from  various  localities,  he  may  fix  with  tolerable  certainty 
upon  the  magnitude  and  form  which  may  be  regarded  as  the  average  and 
type  of  the  species  ;  but,  without  such  opportunities,  a  reliance  upon  such 
characters  will  inevitably  lead  to  the  undue  multiplication  of  species  and  to 
a  confused  and  erroneous  nomenclature." 

In  the  construction  of  genera,  similar  difficulties  present  themselves.  Thus, 
Mr.  Brightwell  complains  (J.  M.  S.  i.  252) — "  It  appears  as  if  we  could  carry 
our  real  knowledge  Httle  beyond  that  of  species  ;  and  when  we  attempt  to 
define  kinds  and  groups,  we  are  met  on  every  side  by  forms  which  set  at 
nought  our  definitions.  With  reference  to  the  species  of  the  present  genus 
{Triceratium),  looking  upon  T.  favus  or  T.  megastomum  as  what  we  con- 
ceive to  be  the  most  perfect  plan  (if  any)  on  which  this  group  is  constructed, 
we  find  all  the  species  diverging  from  it,  and  caiTying  us  to  analogous  forms 
in  other  groups,  or  lost  in  them.     Placing  the  perfect  triangular  forni  of 


98  GENEKAL  HISTORY  OF  THE  INFUSOEIA. 

T.  favus  in  the  centre,  we  may  diverge  in  lines  to  a  circumference  ending  in 
one  line,  in  the  long-anned  T.  Solennoceros,  itself  nearly  resembhng  Desmi- 
clium  tridens  or  D.  hexaceros ;  in  another  line  ending  in  a  form  resembling 
Desmldium  apiculosum  ;  in  another  like  Zygoceros  rhombus,  especially  in  the 
front  view ;  in  another  analogous  to  Amphitetras  antediliwicma ;  and  in 
another  to  Campylodiscus  crihrosus.^' 

Next  after  size  and  form,  markings  existing  on  the  surface  or  within  the 
frustules  have  been  employed  as  specific  and  generic  characteristics  ;  but  with 
these,  as  with  the  fonner  conditions,  great  uncertainty  prevails  in  their  ap- 
plication, as  we  have  ah-eady  seen  in  the  difference  of  opiuion,  regarding  some 
internal  markings  of  Grammatophora,  between  Dr.  Gre\alle  and  Prof.  Smith. 
In  like  manner  the  character,  the  breadth,  the  relative  position  and  distribu- 
tion, the  distinctness  and  the  number  of  striae  on  the  valves,  although 
tolerably  constant  in  some  species,  are,  in  the  majority,  subject  to  gi-eat 
variation.  Then  again  some  natui'alists  coimt  the  number  of  striae  in  a 
given  space,  as,  for  example,  in  the  yxKui^^  ^^  ^^  inch,  whilst  others  advo- 
cate counting  the  entire  number  in  the  length  of  the  valve.  The  latter  plan, 
to  all  appearance,  must  afford  more  certainty,  although  the  trouble  of  it  is 
much  greater ;  for  in  the  growth  of  fmstules  there  would  seem  an  expansion 
of  theii^  walls,  inducing  consequently  a  displacement  of  the  striae  further 
apart ;  and  observation  does  not  confii^m  the  opinion,  that  in  the  imperfectly 
developed  frustules  a  smaller  number  exists,  which  are  added  to  in  course  of 
growth. 

However,  just  as  in  the  case  of  the  form  and  size,  so,  in  this  matter  of  the 
superficial  markings,  there  -udll  be  variations  according  as  the  frustules  result 
from  self- division  and  are  stereotyped  impressions  of  an  already  existing 
form,  or  according  as  they  originate  from  sporangial  frustules  and  may  have 
an  individual  idiosyncrasy,  or  be  modified  in  their  development  by  the  locality, 
and  by  surroimding  cii'cumstances,  season  and  the  like. 

A  writer  in  the  Mic.  Journ.  (1855,  p.  309)  invites  notice  to  another  cir- 
cumstance : — "  Sufficient  attention  has  not  yet  been  paid  to  the  sporangial 
state  of  the  Diatoms.  Prom  the  observations  recorded  by  Thwaites,  Smith, 
and  others,  different  genera  seem  to  follow  different  laws  on  the  subject.  In 
Navicida  this  state  appears  to  be  always  accompanied  by  a  great  dilatation  of 
the  frustule,  and  the  formation  of  a  strong  line  or  band  between  the  median 
line  and  the  margin ;  sometimes  the  new  line  is  nearly  straight  and  parallel 
to  the  median  Hue,  except  near  the  nodule,  Avith  which  it  seems  connected ; 
sometimes  it  is  curved ;  but  whether  both  structures  occur  in  the  same 
species,  or  are  indicative  of  different  species,  no  evidence  has  hitherto  been 
addaced The  striae  appear,  however,  to  preserve  nearly  the  same  in- 
clination to  the  new  or  intermediate  Hues  which  they  did  in  the  non- 
sporangial  state  to  the  median  line  ;  and  hence  the  direction  of  the  striae  is 
not  sufficient  of  itself  to  distinguish  species,  however  good  a  character  it  may 
afford,  unless  regard  be  had  to  the  peculiar  state  of  the  fi-ustule." 

Prof.  Smith  has  endeavoui'ed  to  frame  some  general  rules  for  the  guidance 
of  naturalists  in  instituting  generic  and  specific  characters,  which  we  cannot 
do  better  than  subjoin  in  an  abridged  form  {J.  M.  S.  1855,  pp.  132-134;  and 
Synops.  vol  ii.  p.  xxii).  In  determining  specific  character,  three  circumstances 
are  of  essential  importance:  1.  the  structm^e  of  the  valve ;  2.  the  habitat; 
3.  the  arrangement  of  endochome  in  the  li\ing  frustule. 

The  first  can  be  applied  to  both  living  and  dead  or  fossil  specimens,  and 
affords  the  most  constant  and  obvious  characters.  "  These  varieties  of  struc- 
ture arise  from  the  modes  in  which  the  silex  combines  with  the,  cellulose  of 


OP  THE  DIATOME^.  99 

the  epiderm ;  and  this  combination  seems  to  follow  certain  and  invariable 
laws,  which  are  subject  to  no  derangement  from  the  external  circumstances 
in  which  the  growth  of  the  embrj^o  may  take  place.  The  structure  of  the 
valve  reveals  itself  in  the  character  of  the  striation,  which  may  therefore  be 
found  a  good  specific  distinction."  Thus  the  striae  may  be  costate  or  monili- 
form,  parallel  or  radiate,  reach  the  median  line  or  be  absent  from  a  greater 
or  lesser  portion  of  the  siu'face,  &c.  The  relative  distances  and  the  distinct- 
ness of  the  stria3  are  also  other  features  to  be  recorded,  allowance  being  made 
for  the  influence  of  localities  and  of  age,  and  for  the  fact  of  their  having 
originated  from  the  same  or  from  different  sporangia. 

Next  to  striation  in  importance  is  locality,  which  will  often  aid  to  discri- 
minate between  closely  allied  forms,  since  fresh-  and  salt-water  species 
cannot  exchange  habitats.  Locality  also  seems  even  more  restricted  by  other 
external  conditions  of  a  more  limited  nature. 

Lastly,  the  arrangement  of  the  endochrome  confers  a  specific  character 
more  certain  than  habitat.  Examples  of  various  arrangement  of  gonimic 
substance,  and  of  the  large,  constant,  oil-like  globules,  have  been  already 
given. 

It  follows,  therefore,  that  the  difficulty  of  defining  species  is  much  en- 
hanced where  examples  occur  only  in  a  fossil  state.  Even  in  the  living 
state,  shape  and  size  cannot  be  implicitly  relied  on,  but  gatherings  are  re- 
quired from  different  localities,  and  everj  condition  of  growth  observed,  before 
an  average  size  or  a  typical  outline  can  be  decided  on.  And  although  stria- 
tion is  an  important  guide,  it  often  happens  that  this  feature  is  so  nearly 
alike  in  allied  species  of  the  simple  forms,  such  as  Cocconema,  Cymhella,  and 
Navicula,  that  oiu'  determination  must  be  influenced  by  less  important  con- 
siderations, and  the  habitat,  outline,  and  an^angement  of  cell-contents  all 
require  to  be  brought  imder  review  before  we  should  feel  justified  in  consti- 
tuting a  species. 

In  the  construction  of  genera,  the  several  conditions  (viz.  form,  size,  stria- 
tion, habitat,  and  disposition  of  endochrome)  employed  in  the  determination 
of  species  are  also  resorted  to.  Other  peculiarities,  however,  are  noted, 
such  as  the  transverse  or  longitudinal  lines  or  bands,  indicating  thickenings 
of  the  valves,  the  presence  of  a  central  spot  (umbilicus)  or  of  terminal  ones, 
and  (as  Prof.  Smith  mentions)  ^'  the  obvious  varieties  of  form  or  combination 
to  which  the  ceUules  submit  in  the  progress  of  their  formation,  exhibiting 
themselves  as  hexagonal,  circular,  or  irregular  in  outline,  as  distinct  from 
each  other,  or  as  more  or  less  confiuent."  {Synops.  vol.  ii.  p.  xxiv.) 

Kiitzing  has  extensively  used  the  circumstance  of  the  presence  or  absence, 
the  number  and  the  position  of  apparent  pores,  not  only  in  constituting 
genera,  but  also  the  higher  divisions,  families  and  orders.  The  figure  of 
frustules  on  a  transverse  section,  or  an  end  view,  is  another  point  he  has 
resorted  to  in  framing  his  classification.  He  would,  indeed,  appear  to  assign  a 
yet  higher  importance  to  the  central  spot  or  umbilicus  than  Ehrenberg  him- 
self, siace  he  has  distinguished  his  tribes  Striatce  and  Vittatm,  respectively, 
into  two  orders,  Stomaticce  and  Astomaticce,  according  as  this  structural  pecu- 
liarity is  present  or  absent.  So,  again,  in  the  case  of  the  Navicular  frustules, 
he  has  constituted  Surirella  with  some  other  genera  into  a  family  Surirellece, 
separated  from  Navicula,  Pinnularia,  and  other  genera,  and  placed  in  a  dis- 
tinct order  of  Striatce,  because  the  former  group  is  destitute  of  an  umbilicus 
(hence  Astomaticce),  which  the  latter  possesses  (the  Stomaticce).  Moreover, 
as  the  family  Naviculeae,  along  with  others,  presented  an  umbilicus  on  each 
valve  of  their  frustule,  the  term  Distomaticce  was  applied  to  distinguish  them 

h2 


100  GENEKAL  HISTORY  OF  THE  mFUSORTA. 

from  other  families  having  an  umbilicus  only  on  one  valve — Monostomaticce. 
In  this  plan,  therefore,  Kiitzing  assigned  to  the  circumstance  of  striation  an 
altogether  secondary  place  to  that  of  the  existence  of  a  central  umbilicus, 
asserting  that  the  presence  or  absence  of  transverse  striae  was  inconstant, 
and  therefore  not  to  be  used  in  generic  distinctions. 

Meneghini  critically  reviews  Kiitzing' s  system  of  classification,  and  points 
out  many  anomalies  and  errors  in  it.  "  In  the  three  proposed  tribes,"  re- 
marks this  author,  "  we  have  unnatural  dismemberments  and  associations. 
The  same  conclusion  prevails  also  in  respect  to  the  six  orders,  as  well  as  to 
the  ulterior  divisions  in  the  first  two,  taken  from  the  continuity  or  inter- 
ruption of  the  striae  and  the  presence  of  one  or  two  stomatic  apertures  "  {op. 
cit.  p.  492).  For  instance,  he  asserts  that  the  character  of  the  median 
apertiu-e,  given  as  distinctive  of  Tahellariece  from  Striatellece,  is  absolutely 
false ;  and  he  doubts  generally  of  the  presence,  constancy,  and  value  of  a 
median  aperture  in  framing  such  distinctions  as  Kiitzing  has  done.  The 
Actiniscece  he  would  separate  from  the  Diatomeae. 

Again,  proceeding  on  the  principle  that  no  one  character  can  be  allowed 
an  absolute  value,  he  divides  the  Diatomese  into  two  sections,  the  Actiniscece 
and  Loricatce.     Of  the  latter  he   would  create  8  families: — 1.  Eiinotiece ; 

2.  Fmgilariece  (imiting  with  them  the  Mericliece,  Striatellece,  and  Tahellariece)  ; 

3.  Melosirece,  comprising  the  Coscinodiscece,  Tnpodiscece,  Anguliferce,  Bid- 
chdphieoe,  smd  Angulatce ;  4.  Cocconeidece ;  5.  Achnanthece;  6.  Cymhellece ; 
7.  NaviculecB  (with  aU  the  Siirirellece) ;  8.  Gomphonemeoi  (with  aU  the 
Licmopliorece,  except  the  genus  Licmopliora)^ 

To  the  presence  or  absence  of  an  external  muco-gelatinous  investment 
around  the  silicious  frustules,  this  natui^alist  gave  little  weight  in  framing  a 
classification,  reckoning  it,  together  Tvdth  the  existence  or  not  of  a  pedicle 
or  of  concatenation,  as  scarcely  admissible  in  the  identification  of  species. 

On  the  other  hand,  Prof.  Smith  has  employed  these  circumstances,  con- 
sidered in  relation  to  the  process  of  self- division,  as  the  basis  of  his  system 
of  classification.  He  would  look  to  the  phenomena  of  reproduction  as  the 
most  sure  basis  ;  but  in  the  absence  of  precise  information,  except  in  a  few 
instances,  these  are  at  present  inapplicable,  and  self-division  seems  to  him 
"  to  come  next  in  order,  as  a  most  important  function  connected  with  in- 
crease and  growth,  and  to  supply  the  necessary  variety  of  phenomena  on 
which  to  ground  our  sectional  divisions."  And  he  thus  proceeds  to  explain 
his  plan  (Synops.  i.  p.  xxviii) : — 

"  1  have  therefore  separated  those  forms  where  self-division  is  accom- 
panied by  the  secretion  of  a  permanent  gelatinous  or  membranaceous  envelope, 
in  which  the  frustules  are  subsequently  imbedded,  from  those  in  which  such 
secretion  is  altogether  absent,  or  is  represented  merely  by  a  cushion  or 
stipes,  to  which  the  frustules  are  attached  by  a  small  portion  of  their  sui'- 
face ;  and  I  have  placed  the  latter,  as  of  simpler  organization,  in  my  first 
tribe,  arranging  the  genera  belonging  to  it  into  subtribes,  depending  upon 
the  permanency  or  otherwise  of  the  connecting-membrane,  another  product 
of  the  self-dividing  process.  This  enables  me  to  place  apart  those  genera 
whose  species  present  us  with  frustules  in  which  the  union  of  the  cells  is 
dissolved  almost  immediately  upon  the  completion  of  self- division,  as  well  as 
those  where  a  cushion  or  stipes  still  maintains  a  kind  of  indirect  individuality 
in  the  divided  frustules,  from  the  genera  in  which  the  cells  cohere  after 
gemmiparous  increase,  and  by  such  coherence  form  filaments  of  various 
lengths  and  forms,  allotting  the  latter  to  subtribes  which  respectively  pre- 
sent a  compressed  filament,  a  zigzag  chain,  or  a  cylindrical  thread.     In  the 


OF  THE  DIATOME^. 


101 


second  tribe,  including  those  genera  which  have  frondose  forms,  I  find  cha- 
racters for  my  subtribes  in  the  natui-e  of  the  frond  and  the  arrangement  of 
the  frustules. 

''I  do  not  propose  this  arrangement  as  free  from  exceptions  or  even  serious 
defects  ;  but  I  have  adopted  it  in  preference  to  those  hitherto  given,  as  bring- 
ing more  fi'equently  together  forms  allied  in  structui'e  and  mode  of  growth, 
and  as  being  at  the  same  time  more  strictly  in  accordance  with  the  external 
physiognomies  of  these  organisms,  and  therefore  more  likely  to  be  appre- 
hended by  the  inquirer  entering  upon  the  study  of  this  department  of  natui^e. 
A  wider  study  of  Diatomaceous  forms  will  doubtless  lead  to  more  accurate 
and  more  natural  generalizations." 

We  subjoin  the  systems  of  classification  proposed  by  Kutzing  and  by 
Smith.     The  former  is  presented  in  a  tabular  form — 

DIATOME^.  * 


Tribe  I. 

Striatae. 


Tribe  II. 
Vittate. 


Tribe   III. 
Areolatae. 


Order  I. 

AsTOMATICiE. 

Without  a  central 
opening  on  the 
secondary  side. 


(     *  Transverse  striae  unbroken. 
Family  1.  Eunotieae. 

2.  Meridieae. 

3.  Fragilarieae. 

**  Striae  broken  (interrupted)  in  the  median  line. 
Family  4.  Melosireae. 


Order  II. 

StOMATICjE. 

With  the  central 
opening. 

i 
Order  I.  ) 

ASTOMATIC.E.         I 

Withovit  median   V 
aperture  on  se- 
condary side.     ) 
Order  II.         ^ 
Stomatic.e."       I 
With  a  large  dis-  [ 
tinct  one. 


5.  Smirelleae. 

a.  MONOSTOMATIC^. 

Family  6.  Cocconeideae. 
7.  Achnantheae. 

b.  DlSTOMATICE. 


f  Having  a  median  aperture  on  only 
\     one  of  the  two  secondary  surfaces. 


Order  I. 

DiSCIFORM.E. 

Order  II. 
Appendiculat^. 
I  Appended  doubt- 
i^        ful  forms. 


Family  8.  Cymbelleae, 

9.  Gomphonemeae, 

10.  Naviculeae. 


11.  Licmophoreae. 

12.  Striatelleae. 


13.  Tabellarie®, 


14.  Coscinodisceae. 

15.  Anguhferae. 

16.  Tripodisceae. 

17.  Biddulphieae. 

18.  Angulatae. 

19.  Actinisceae. 


fWith  a  median  aperture  on  each 
\     secondary  surface. 


The  Synoptical  Table  of  Prof.  Smith  contains  only  those  genera  then 
knoAr^Ti  in  Britain ;  but  since  the  date  of  its  publication  not  a  few  others 
have  been  added  to  the  list. 


Class  CRYPTOGAMIA. 

Subclass  ALG^.        Natubal  Order  DIATOMACE^-. 

Plant  a  Feustule  ;  consisting  of  a  unilocular  or  imperfectly  septate  cell 
invested  with  a  bivalve   silicious   epidermis.      Gemmiparous   increase,   by 


102  GENERAL  HISTORY  OF  THE  INFUSORIA. 

Self-Division  ;  during  which  process  the  cell  secretes  a  more  or  less  sili- 
cious  Connecting  Membrane.  Eeprobtjction,  by  Conjugation  and  the 
tbrmation  of  Sporangia. 

Teibe  I.  Frustules  naked ;  not  imbedded  in  gelatine  nor  enclosed  in  mem- 
branaceous tubes. 
SuBTKiBE  1 .   Connecting  memhrane  deciduous  ;  frustides  solitary  or  du- 
ring self-division  in  pairs,  rarely  in  greater  numbers, 
adherent  or  free,  dispersed,  or  aggregated  into  a  mucous 
stratum. 
22  Genera.  Epithemia,  Eunotia,  Cymbella,  Amphora,  Cocconeis, 
Coscinodiseus,  Eupodiscus,  Actinocyclus,  Arachnoi- 
discus,     Triceratium,     Cyclotella,     Campylodiscus, 
Surirella,     Tryblionella,    Cymatopleura,    Nitzschia, 
*  Amphiprora,    Amphiplem^a,    Navicnla,    Pinnularia, 

Stauroneis,  Pleiirosigma. 

SuBTEiBE  2.   Connecting   membrane   subpersistent ;   frustules   after   self- 
division  attached  by  a  gelatinous  cushion,  or  dichoto- 
mous  stipes. 
7  Genera.  Synedi-a,  Doryphora,   Cocconema,   Gomphonema,   Po- 
dosphenia,  Ehipidophora,  Licmophora. 
Subtribe  3.   Connecting  membrane  evanescent,  or  obsolete  ;  frustides  after 
self -division  miited  into  a  compressed  filament. 

12  Genera.  Meridion,  Bacillaria,  Himantidiiim,  Odontidium,  Den- 
ticnla,  Fragilaria,  Eiicampia,  Achnanthes,  Achnan- 
thidium,  Rhabdonema,  Striatella,  Tetracyclns. 

Subtribe  4.  Connecting  membrane  subpersistent ;  frustides  after  self- 
division  united  into  a  zigzag  chain. 

6  Genera.    Diatoma,    Grammatophora,   Tabellaria,   Amphitetras, 
Biddulphia,  Isthmia. 

Subteibe  5.  Connecting  memhrane  subpersistent  as  a  silicious  annulus ; 
frustules  after  self-divisio7i  united  into  a  cylindrical 
filament. 

3  Geneea.  Podosira,  Melosira,  Orthosira. 

Tribe  II.  Frustules  invested  with  a  gelatinous  or  membranaceous  envelope. 
Subteibe  6.  Frond  indefinite,  mammillate  ;  frustules  scattered. 

1  Genus.  Mastogloia. 

Subteibe  7.  Frond  definite,  compressed  or  globular  ;  frustules  scattered. 

2  Geneea.  Dickieia,  Berkelejda. 

Subteibe  8.  Frond  definite,  filamentous  ;  frustules  in  rows. 

3  Geneea.  Encyonema,  Colletonema,  Schizonema. 
Subteibe  9.  Frond  definite,  filamentous  ;  frustules  fasciculated. 

1  Genus.  Homoeocladia. 

On  the  Mode  of  obtaining  Diatome^.  Peepaeation  of  Diatomaceous 
Deposits  mixed  with  Mud  oe  in  the  Eossil  State.  Peeseevation  of  Spe- 
cimens.— Many  hints  on  the  obtaining  of  specimens  of  Diatomea?  are  scat- 


OF  THE  DIATOME.E.  103 

tered  in  previous  secti-ons  of  this  history  of  the  Order,  particularly  in  that 
on  their  habitats  (p.  75) ;  yet,  to  make  the  directions  complete,  additional 
details  are  necessary. 

AMiere  Diatomese  in  the  li\ing  state  exist  in  any  considerable  number, 
they  usually  fomi  a  brilliant  cinnamon,  or  sometimes  an  olive-brown  film  or 
patch,  and  thereby  become  visible  to  the  naked  eye  or  to  an  ordinary  lens, 
adherent  to  various  water- weeds,  to  decayed  portions  of  wood,  leaves,  or 
other  floating  substances,  or  as  a  patch  on  the  mud  at  the  bottom,  or  other- 
wise floating  on  the  surface  of  the  pond  as  a  scum  or  film.  Besides  such 
positions  and  such  collections,  Diatomeae  exist  diffused  more  or  less  abun- 
dantly thi^ough  the  water  or  in  the  mud  itself  (see  p.  75  et  seq.). 

When  seen  adherent  to  an  aquatic  plant,  the  process  of  collection  is  very 
simple — by  carefully  gathering  or  removing  the  j^lant  from  the  water  and 
washing  it  to  detach  the  Diatomaceous  fi^ustules,  if  these  cannot  be  more 
advantageously  viewed  whilst  still  adherent  to  its  stem  or  leaves.  So,  too, 
where,  mostly  in  conjunction  with  other  organisms,  the  Diatomeae  float  in 
mass,  like  a  scum  on  the  siuface,  nothing  is  easier  than  to  lightly  skim  the 
collection  from  the  suiface.  But  when  the  layer  of  frustules  reposes  on  the 
surface,  or  is  more  or  less  intermixed  with  the  mud,  some  additional  pre- 
cautions are  required  in  theii'  collection,  unless  indeed  the  film  has  sufficient 
tenacity,  by  cohesion  of  its  component  frustules,  as  in  the  case  of  Schizonemeae, 
to  allow  of  its  being  raised  en  masse  upon  some  thin  flat  instrument,  a  spoon 
or  spatula,  insinuated  beneath  it. 

The  general  methods  of  collection  applicable  to  the  Desmidieae  and  other 
minute  Algae  are  equally  so  to  the  Diatomeae,  whilst  various  modifications 
will  suggest  themselves  to  the  mind  of  every  practical  natui^ahst  to  meet  the 
vaiying  circumstances  under  which  he  makes  the  collection.  Mr.  E,alfs  has 
kindly  fui^nished  us  with  notes  on  this  point.  He  writes — "  It  is  often 
difficult  to  prociu'e  clear  specimens  of  those  species  which  form  strata  on 
mud ;  most  of  them,  however,  can  be  obtained,  tolerably  free  from  the  mud 
on  which  they  congregate,  by  the  following  method,  which  is  applicable  both 
to  those  found  in  marine  situations  and  to  those  gathered  from  the  wayside. 
When  the  water  is  somewhat  dried  ujd,  if  the  finger  be  pressed  upon  the 
stratum  with  a  gentle  force,  the  Diatomaceae  wiU  adhere  to  the  finger,  and 
may  then  be  removed  by  scraping  them  oif  upon  a  piece  of  linen  folded  over 
the  edge  of  a  tin  box  or  of  a  knife ;  by  repeating  this  process,  a  sufficient 
quantity  can  easily  be  collected.  At  fiLi^st,  probably,  a  portion  of  mud,  espe- 
cially if  very  wet,  will  also  be  taken  up ;  but  a  little  practice  will  soon  show 
the  force  requisite  for  places  where  the  water  is  plentiful,  and  for  those 
where  it  is  nearly  dried  up.  Specimens  thus  collected  can  be  prepared  for 
mounting  with  much  less  trouble  than  if  gathered  mixed  with  a  large  quan- 
tity of  dirt." 

^VTien  it  is  mshed  to  capture  frustules  diffused  in  water,  a  piece  of  muslin 
may  be  used  as  a  filter,  just  as  for  Desmidieae,  and  the  residue  left  upon 
it  examined  as  it  is,  or,  if  requii^ed,  washed,  to  detach  foreign  matters  mixed 
wdth  it.  Where  some  admixture  of  mud  is  imavoidable,  frequent  washing  of 
the  collected  substance  ^vill  often  suffice  to  separate  sufficiently  the  silicious 
frustules  from  the  other  particles — the  heavier  grains  of  sand  sinking  to  the 
bottom  of  the  vessel,  while  the  Diatoms  are  still  suppended  in  the  fluid ;  and 
on  the  other  hand,  the  decayed  organic  and  other  matters,  lighter  than  the 
frustules,  will  remain  in  the  supernatant  liquid  after  the  latter  are  precipi- 
tated. Repeated  careful  decanting  and  washing  may  be  aU,  therefore,  that  is 
required. 

Another  method  applicable  to  recent  living  specimens,  dependent  on  the 


104  GENERAL  HISTORY  OF  THE  INFrSORIA. 

tendency  towards  the  light,  at  least,  of  many  species,  may  be  adopted  by 
placing  the  half-liquid  mud  in  shallow  pans  or  plates  in  the  sunshine,  when 
many  species  may  be  found  to  rise  as  a  film  on  the  surface,  or  to  congregate 
near  the  edge  or  sides  of  the  vessel. 

When  the  frastules  are  much  intermixed  mth  mud,  which  is,  under  cer- 
tain circumstances,  inevitable,  various  plans  have  been  adopted  for  separating 
them  for  examination.  Mr.  Okeden  details  the  following  plan,  which,  with 
certain  modifications  to  be  mentioned,  has  been  described  ako  by  Dr.  H. 
Munro  : — 

"  The  plan  "  {J.  M.  S.  1855,  pp.  158, 159)  <'  consists  in  making  the  deposits 
fall  through  a  constant  depth  of  water,  in  various  periods  of  time  ;  thus 
dividing  the  Diatoms,  according  to  their  sizes,  into  portions  of  several  dif- 
ferent gravities."  It  is  thus  carried  out :  "  Take  about  a  cubic  inch  of  the 
clay  to  be  examined,  digest  it  for  about  four  hours  in  strong  nitric  acid  at  a 
moderate  temperature  ;  now  add  gradually  an  equal  quantity  of  hydrochloric 
acid,  effervescence  takes  place,  a  further  action  on  the  clay  ensues ;  keep 
boiling  for  about  three  hours  more,  occasionally  stirring,  and  then  allow  the 
mixture  to  cool  and  settle  do^vn,  which  it  wiU  do  in  about  an  hour ;  pour  off 
the  superfluous  acid  and  wash  the  residue  repeatedly  with  water,  so  as  to  get 
rid  of  the  remaining  acid. 

"  The  next  operation  is  to  divide  the  sediment  into  portions  of  various 
specific  gravities :  for  this  piu'pose  it  is  necessary  to  have  several  beakers, 
about  3  or  4  inches  in  height,  and  about  11-  to  2  inches  in  diameter ;  also 
one  very  large  beaker,  about  6  to  9  inches  in  diameter :  we  wiU  call  the  large 
beaker  A.  'Now  transfer  the  sediment  into  one  of  the  small  beakers,  and 
pour  in  water  tiU  there  is  just  2  inches  depth  of  water  in  the  glass.  Stir, 
and  let  stand  half  a  minute  by  the  watch,  and  then  pour  off  carefully  into 
the  large  beaker  A ;  repeat  this  about  half  a  dozen  times,  each  time  pouring 
off  into  A  all  that  does  not  fall  thi^ough  the  2  inches  of  water  in  the  half- 
minute,  and  at  last  the  small  beaker  wiU  contain  only  what  falls  through 
2  inches  of  water  in  half  a  minute.  jSTow  let  A  stand  about  half  an  hour, 
pour  off  carefully,  and  transfer  the  sediment  in  A  to  another  small  beaker  ; 
put  2  inches  of  water  with  it,  stir  and  let  stand  for  2^  minutes,  then  pour 
off  into  A.  Repeat  this  about  six  times,  and  there  will  now  be  another  small 
beaker  containing  all  that  falls  through  2  inches  of  water  in  2|  miautes, 
whUe  in  A  is  all  that  does  not  fall  through  that  distance  in  that  period.  Let 
A  stand  half  an  hour,  pour  off  and  transfer  the  sediment  to  another  small 
beaker,  stir  and  let  it  stand  ^ye  minutes,  pour  ofi"  into  A  as  before,  and  repeat 
this  as  before  about  six  times.  There  is  now  another  beaker,  containing  aU 
that  falls  through  2  inches  of  water  in  5  minutes.  After  this  I  do  not  di\ide 
them  any  further,  but  call  the  last  remainder,  or  what  remains  in  A  after 
it  has  stood  its  half-hour,  '  Kot  in  five  minutes.'  Thus  we  have  four 
different  glasses,  containing  Diatoms  and  clay  mixed,  of  four  different  densi- 
ties :  thus,  0  to  i ;  -i-  to  2-i- ;  2i  to  5  ;  not  in  5.  There  is  now  a  method  of 
concentrating  the  coarsest  of  these  sediments,  namely  the  0  to  i,  the  i  to 
21-,  and  sometimes  the  21-  to  5.  It  consists  in  taking  the  beaker  containing 
the  sediment  and  pouilng  about  an  inch  of  water  on  it.  Let  it  settle  about 
5  minutes,  and  then  place  the  glass  on  a  table,  and  impart  a  whirling  motion 
to  the  whole  by  moving  it  roimd  and  round,  when  the  greatest  portion  of  the 
Diatoms  will  rise  up  in  a  sort  of  eddy,  while  the  particles  of  mud  or  sand 
will  remain  at  the  bottom,  even  though  they  are  of  the  same  specific  gravity 
as  the  Diatoms,  and  have  fallen  through  the  same  distance  of  water  in  the 
same  time.  This  is  because  the  Diatoms  are  mostly  ^rt^  and  thin,  while  the 
particles  of  sand  and  mud  are  round ;  in  the  same  way,  if  we  take  a  round 


or  THE  DIATOME^.  105 

pebble  and  an  oyster- shell  both  of  the  same  weight,  and  throw  both  hori- 
zontally into  the  water,  the  pebble  vnll  reach  the  bottom  sooner  than  the 
oyster-shell.  80,  when  the  whirling  motion  is  imparted  to  the  glass,  the  thin 
flat  shells  of  the  Diatoms  will  rise  up  in  a  cloud,  while  the  round  particles  of 
mud  and  sand  will  remain  behind ;  when  the  cloud  rises  up,  pour  it  off  quickly 
and  dextrously  into  another  glass,  and,  if  necessaiy,  repeat  the  process ;  and 
a  little  practice  will  enable  the  operator  to  separate  all  the  Diatoms  most 
effectually.  I  have  said  before  that  this  process  will  only  apply  to  the  0  to  ^, 
^  to  2i,  and  sometimes  the  2^  to  5  sediment,  but  not  to  any  finer  one ; 
practice  will  soon  teach  this.  The  '  not  in  5  '  cannot  be  concentrated — it  is 
too  fine,  and  the  whole  rises  together  on  imparting  the  whirling  motion  to  it. 

"  It  is  not  necessaiy  to  abide  invariably  by  the  divisions  of  time  which  I 
have  given  here. 

"  These  must  be  varied,  of  coui-se,  according  to  the  nature  of  the  clay  to  be 
examined.  For  instance,  in  a  clay  I  have  recently  tried  from  34  feet  below 
the  bed  of  the  river  at  Cardiff,  nearly  the  whole  of  what  was  left  after  the 
0  to  i  fell  in  the  ^  to  2^.  I  therefore  divided  it  thus  :  0  to  i,  -i-  to  li,  and 
li  to  2^  ;  a  little  practice  wiU.  soon  teach  this. 

"  The  advantages  of  the  plan  are,  I  think,  ob\'ious.  In  the  fu^st  or  coarsest 
sediments  we  get  all  the  larger  and  finer  Diatoms  by  themselves,  unmixed 
"svith,  and  consequently  unobscui'ed  by,  the  innumerable  smaller  ones  and 
the  fine  particles  of  mud  and  sand,  while,  if  any  of  them,  such  as  the  Eupo- 
disci  or  Cmnpylodisci,  are  rare,  they  are  sure  to  be  found  in  either  the  first  or 
second  di\dsion  of  densities,  and  by  their  being  concentrated  and  brought  as 
it  were  into  a  small  compass,  the  detection  of  them  is  easy  and  certain. 

"  In  the  next  division,  or  the  2^  to  5,  we  shall  find  the  moderate-sized 
Diatoms ;  and  lastly,  in  the  '  not  in  5,'  we  get  a  mass  of  the  remaining  and 
smaller  Diatoms,  all  of  which  small  ones  are  themselves  the  more  readily  seen 
and  identified  when  separated  from  their  larger  brethren. 

"  I  would  ventui'e  to  add,  moreover,  that  I  think  the  examination  of  these 
deposits  for  the  various  species  is  much  facilitated,  as  the  slides  containing 
the  0  to  li  sediment  may  be  examined  with  the  inch  objective,  the  -J-inch 
will  do  to  examine  the  1^  to  2^  and  2^  to  5,  while  the  -i-inch  need  not  be 
used  till  we  come  to  the  '  not  in  5 ; '  whereas,  were  they  all  mixed,  the  i-inch 
would  be  required  to  examine  the  whole. 

"  I  should  add,  that  what  is  poui-ed  off  the  large  beaker  A,  after  it  has 
stood  the  half-hour  each  time,  may  be  fiimg  away  and  the  sediment  only 
transfeiTed  to  the  small  beakers,  as  from  the  large  size  of  it  there  T\all  rarely 
be  more  than  2  inches  depth  of  water  in  it,  and  half-an-hour  is  ample  time 
to  ensure  every  diatomaceous  particle  falling  to  the  bottom  and  being  pre- 
served and  detected  in  one  or  the  other  of  the  divisions." 

Dr.  Munro's  plan  is  a  variation  of  the  above  proceeding,  and  is  thus  de- 
tailed {J.  M.  S.  1855,  p.  242)  :  ''  I  first  boO.  the  deposit  in  strong  hydrochloric 
acid  for  five  or  ten  minutes,  then  allow  it  to  subside,  pour  off  all  the  acid,  and 
by  a  few  washings  get  as  much  of  it  away  as  possible  ;  then  treat  the  deposit 
in  the  same  way  T\ith  strong  nitric  acid,  washing  the  deposit  by  repeated 
washings  to  get  rid  of  the  remaining  acid.  When  this  is  done,  I  then  sepa- 
rate the  Diatoms  according  to  their  different  gravities  by  allowing  them  to 
pass  through  a  column  of  water  in  the  following  manner : — 

''  I  take  a  long  glass  tube  about  fom^  feet  long  and  half  an  inch  in  bore. 
At  the  bottom  of  this  tube  is  fixed  a  stop-cock  to  enable  me  to  let  out  any  of 
the  Diatoms  duiing  any  stage  of  the  process.  Having  nearly  filled  this  tube 
with.  distHled  water,  I  pour  in  my  deposit  washed  free  from  the  acids.  I 
watch  the  deposit  as  it  falls  sloAvly  and  gradually  down  the  tube,  and  with  a 


106  GENEEAL  HISTOEY  OF  THE  INFUSOEIA. 

Coddington  lens  can  easily  detect  the  larger  Diatoms  as  they  are  precipitated. 
In  about  a  quarter  of  an  hour,  many  of  the  larger  forms  will  have  descended 
to  the  bottom  of  the  tube.  By  turning  the  tap  at  the  bottom  of  the  tube,  I 
let  out  a  di'op  of  the  mixture  on  a  slide,  and  examine  it  Tvdth  a  low  power 
(i-inch)  ;  and  if  it  be  tolerably  clear,  and  the  Diatoms  of  one  character,  I  then 
let  off  five  or  six  inches  of  the  mixture  into  a  test-tube,  and  set  it  aside  for 
re -examination  after  the  Diatoms  have  subsided.  In  a  quarter  of  an  hour 
more,  I  again  let  off  into  another  test-tube  six  or  eight  inches  more  of  the 
mixture,  and  place  it  aside  to  settle.  In  half  an  hour  more  I  let  off  into 
another  test-tube  six  or  eight  inches  of  the  mixtm^e,  which  will  contain  the 
finer  Diatoms  by  themselves,  generally  free  from  all  mud  and  sand.  I  then 
pass  each  of  these  washings  again  through  the  long  tube  of  distilled  water ; 
and  by  examining  the  mixture  during  the  process  of  its  subsidence,  I  am 
enabled  to  let  out  the  heavier  particles  of  sand  or  mud,  and  to  obtain  pretty 
clean  all  those  Diatoms  which  are  alike  in  size,  or  at  all  events  in  specific 
gravity.  Some  Diatoms  take  a  longer  time  than  others  in  settling  to  the 
bottom  of  the  tube,  and  separating  themselves  from  extraneous  matter,  such 
as  the  Nitzschia,  CJosteriwn,  &c. ;  but,  by  a  little  patience,  and  an  extra 
washing  through  the  tube,  these  difficulties  may,  in  a  great  measure,  be 
overcome.  By  this  method,  I  have  found  the  Pleurosigmata,  P'lnnularice, 
Surirellce,  and  Synedrce  very  well  separated,  those  of  a  like  character  being 
found  together.  I  have  been  stimulated  to  send  these  few  remarks  on  the 
washing  of  Diatomacese,  on  account  of  the  great  difficulty  I  have  hitherto 
experienced  in  procuiing  slides  free  from  mud,  sand,  and  other  extraneous 
matters." 

Mr.  Okeden  offers  the  following  plan  for  obtaining  specimens  imbedded  in 
mud  at  considerable  depths,  in  making  borings  for  engineering  purposes.  He 
prefaces  the  description  of  his  apparatus  by  that  of  the  usual  boring  ap- 
paratus, which  ^'  consists  essentially  of  any  number  of  iron  rods  "  (J.  M.  S. 
1854,  p.  2Q),  "which  screw  one  into  the  other  ;  to  one  of  these  is  screwed  an 
auger  or  a  chisel-point,  as  the  case  may  requii'e.  This  is  inserted  into  the 
groimd  to  be  tested,  and  worked  round  by  manual  force  and  downward  pres- 
sure, length  after  length  of  rod  being  added  as  the  ground  is  penetrated.  In 
addition,  then,  to  this  apparatus,  I  obtained,  fii'st,  several  lengths  of  wrought- 
iron  gas-pipe,  about  an  inch  in  diameter,  and  each  screwing  into  the  other ; 
and  also  a  similar  number  of  iron  rods,  each  a  few  inches  longer  than  the 
lengths  of  gas-piping,  and  each  also  screwing  into  the  other :  to  the  end  of 
one  of  these  lengths  of  rod  is  attached  a  cork  of  the  exact  diameter  of  the 
gas-pipe,  or  a  trifle  larger.  This  cork  is  fixed  by  a  washer  and  nut.  The 
gas-piping  should  be  in  lengths  of  about  8  feet  each,  as  this  is  the  most  con- 
venient in  work :  one  of  these  lengths  should  also  be  again  divided  into  two 
parts,  which  must,  however,  screw  and  unscrew ;  and  this  length  is  to  be 
the  one  first  put  into  the  ground  or  mud,  for  reasons  which  I  will  presently 
explain. 

"  The  mode  of  proceeding  is  as  follows  :  First,  a  hole  is  bored  to  the  requii'cd 
depth — say  20  feet — mth  the  usual  boring  apparatus  ;  this  done,  the  appa- 
ratus is  di^awn  out,  the  jointed  length  of  gas-pipe  is  now  introduced, — the  end 
of  it,  with  the  rod  to  which  the  cork  is  attached,  having  been  previously 
stopped,  the  rod  passing  up  the  centre  of  the  gas-pipe ;  this  is  let  down  the 
hole,  another  length  of  pipe  being  attached,  and  another  length  of  rod,  and 
so  on,  length  after  length  of  pipe  and  rod,  until  the  bottom  of  the  hole  is 
reached.  We  shall  thus  have  a  continuous  length  of  gas-piping,  which  wiU 
be  penetrated  by  a  continuous  length  of  iron  rod  attached  to  the  cork  at  the 
end  of  the  pipe.    It  is  obvious  that  this  cork  will  entirely  prevent  any  foreign 


OF  THE  DIATOME^.  107 

matter  from  entering  the  gas-pipe.  Ha\dng  thus  reached  the  bottom  of  the 
hole,  now  pull  up  the  cork  into  the  gas-pipe  about  4  feet,  by  means  of  the 
rod  attached  to  it,  and  then  j)^^ss  the  whole  apparatus  into  the  soft  mud. 
The  pressure  will  now  diive  the  mud  up  into  the  pipe  as  far  as  the  cork  is 
di'awn  up.  Now  remove  the  whole  apparatus,  and  by  means  of  the  rod  push 
the  cork  back  again  to  the  end  of  the  last  length  of  pipe,  when  the  charge  of 
mud  -^ill  be  driven  out  in  the  form  of  a  sausage ;  and  by  rejecting  the  two 
ends  of  it,  and  taking  only  the  middle  piece,  we  may  be  perfectly  sure  that 
the  mud  at  that  depth,  and  that  only,  has  been  obtained. 

"  Ha\dng  secured  the  prize,  the  short  length  of  piping  which  contained  it 
is  now  to  be  unscrewed,  and  carefully  washed  ^vith  a  common  gun- cleaning 
rod  and  some  tow,  when  it  is  ready  for  another  experiment. 

"  With  this  apparatus,  then,  I  have  penetrated  Neyland  mud  in  various 
places  to  depths  of  20,  30,  and  40  feet." 

The  Diatomeae  existing  often  so  abimdantly  in  Guano  may  be  separated  on 
a  simpler  plan  to  that  pui^sued  in  the  case  of  sedimentary  deposits  and  col- 
lections of  fossil  specimens.  The  proceeding  is  always  preceded  by  several 
washings  in  clear  water,  and  by  pouring  it  off  carefully,  after  allowing 
a  sufficient  time  for  the  insoluble  and  more  weighty  particles  to  subside. 
The  subsided  matter  is  then  treated  with  hydrochloric  (muriatic)  acid  several 
times, — a  due  inter\' al  being  allowed  for  the  cessation  of  effervescence  and 
for  the  solid  particles  to  settle  before  the  decanting  of  the  liquid  and  the  ap- 
plication of  a  fresh  quantity.  A\Tien  the  muriatic  acid  ceases  to  produce  any 
chemical  action,  as  evidenced  by  effervescence,  nitric  acid  should  be  substi- 
tuted and  used  in  a  similar  way  two  or  three  times,  and  the  mixture  raised 
to  nearly  or  quite  a  boiling  heat,  after  which  the  powder  collected  at  the 
bottom  of  the  vessel — a  conical  one  should,  by  the  way,  be  preferred,  such  as 
chemists  know  by  the  name  of  "  precipitate  glasses  " — is  to  be  washed  re- 
peatedly in  pure  water.  The  resultant  substance  will  be  found  to  be  com- 
posed of  silicious  particles,  which  are  either  Diatomaceous  frustules  or  the 
silicious  spicules  of  Sponges. 

Prof.  Bailey,  in  a  recent  number  of  SilUman^s  Journal,  1856  (p.  145),  re- 
commends the  following  method  of  cleaning  Diatomaceous  deposits,  as  more 
speedy  and  efficacious  than  any  other  he  has  tried,  whether  mixed  with 
soun(hngs,  guano,  or  with  mud,  &c. : — "  Dissolve  out  the  lime  compoimds,  if 
present,  by  means  of  nitric  or  hydrochloric  acid,  wash,  and  fflter.  Then  put 
the  moist  contents  of  the  fflter  into  a  porcelain  capsule  with  enough  strong 
sulphuric  acid  to  make  the  whole  a  fluid  mass.  Heat  the  capsule  over  a  spiiit- 
lamp  until  the  organic  matters  are  aU  charred,  and  continue  the  heat  until 
strong  acid  fiimes  are  evolved.  Keep  the  capsule  hot,  and  add,  in  minute 
portions  at  a  time,  ffnely  powdered  chlorate  of  potassa.  If  the  acid  is  hot 
enough  to  give  off  fumes,  the  chlorate  'v\all  be  immediately  decomposed  with- 
out the  accimiulation  of  explosive  gases,  and  it  will  exert  so  powerful  an 
oxidizing  action,  that  in  a  few  moments  a  carbonaceous  material  as  black  as 
ink  will  become  perfectly  clean  and  colourless.  Nothing  now  will  remain  to 
be  done  but  to  wash  off  the  acid,  which  is  best  done  by  the  addition  of  water 
and  repeated  decantations.  I  would  also  advise  that  the  materials  thus  cleaned 
should  not  be  dried,  but  should  be  kept  in  bottles  with  a  little  alcohol,  which 
prevents  their  felting  together,  and  does  not  allow  the  growth  of  the  byssoid 
plants  which  often  develope  in  water. 

"  It  is  necessaiy  to  caution  those  not  familiar  with  chemistry  against  using 
the  chlorate  of  potassa  with  sulphui^ic  acid  in  any  other  way  than  above  di- 
rected, as  violent  and  dangerous  explosions  might  result.  The  process  as 
above  given  is  perfectly  safe  and  very  effective." 

Another  plan  of  separation  of  the  shells  of  Diatomeoe  or  of  Foraminifera 


108  GENEEAL  BISTOEY  OF  THE  INFUSOEIA. 

is  siiecessMly  adopted  by  Prof.  Bailey  and  D'Orbigny,  and  is  thus  described 
by  the  former  {Proceedings  of  AmeAcan  Assoc,  for  the  Advancement  of  Science, 
1849,  p.  409)  : — "  A\Tiere  the  mixtiu-e  of  inorganic  matter  is  in  large  propor- 
tion to  the  Infusoria  and  other  microscopic  organisms,  and  corresponds  nearly 
in  specific  gravity,"  the  deposit  is  to  be  thoroughly  dried,  whereby  the  minute 
unbroken  shells  wiR  become  filled  with  air,  and  consequently  when  rapidly 
stirred  up  with  water  they  will  be  buoyed  up,  and  continue  suspended  after 
the  intermixed  sand  has  settled  at  the  bottom.  They  may  then  be  easily  re- 
moved from  the  suiface  and  transferred  by  alternately  touching  the  surface 
of  the  water  with  the  finger,  and  the  glass  slide  on  which  they  are  to  be  placed. 
The  sediment,  if  diied  again,  will  often  yield  another  abundant  supply  of  the 
minute  shells.  "  By  the  above  means,"  adds  Dr.  Bailey,  "  I  have  obtained 
exquisite  specimens  from  the  bottom  of  diied-up  ponds,  fi'om  the  sands  of 
harbours,  and  from  the  mud  attached  to  floating  ice  in  the  Hudson  Eiver, — 
materials  presenting  the  two  extremes  of  very  coarse  gravel  and  the  finest 
sediment,  neither  of  which  would  have  given  good  residts  by  any  other 
process." 

In  the  case  of  some  deposits  the  shells  of  the  Diatomaceae  are  so  far  the 
chief  constituents,  that  no  preparation  is  needed  before  subjecting  them  to 
microscopic  investigation. 

The  cohesion  of  Diatomaceous  deposits  is  at  times  so  great  that  a  difficulty 
is  encountered  in  separating  them.  A  method  of  dealing  with  such  is  de- 
tailed by  Prof.  Bailey  (Sill.  Journ.  1856,  p.  356) : — "  Many  masses  of  fossil 
Diatomaceae  are  so  strongly  coherent,  that  they  cannot  be  diff'used  in  water 
(for  the  purpose  of  mounting  in  balsam)  without  a  degree  of  mechanical  vio- 
lence which  reduces  to  fragments  many  of  the  most  beautiful  and  interesting 
forms.  This  is  particularly  the  case  with  some  specimens  from  the  '  infusorial 
deposits '  of  Cahfornia.  Some  of  these  I  endeavoured  to  break  up  by  boiling 
in  water  and  in  acids,  and  also  by  repeated  freezing  and  thawing  when  moist- 
ened, but  without  good  results  in  either  case.  At  last  it  occuiTcd  to  me  that 
the  adherence  might  be  due  to  a  slight  portion  of  a  silicious  cement,  which 
the  cautious  use  of  an  alkaline  solution  might  remove  without  destrojdng  any 
but  the  most  minute  shells  of  the  Diatoms.  As  the  case  appeared  a  desperate 
one,  a  '  heroic  remedy '  was  applied,  which  was,  to  boil  small  lumps  of  the 
Diatomaceous  mass  in  a  strong  solution  of  caustic  potassa  or  soda.  This  proved 
to  be  perfectly  efficacious,  as  the  masses  under  this  treatment  rapidly  split  up 
along  the  planes  of  lamination  and  then  crumbled  to  mud,  which,  being  im- 
mediately poured  into  a  large  quantity  of  water,  ceased  to  be  acted  upon  by 
the  alkali,  and  gave,  when  thoroughly  washed,  not  only  all  the  large  shells 
of  the  Diatoms  in  a  state  of  unhoped-for  perfection,  but  also  furnished  abun- 
dance of  the  minute  forms.  Having  obtained  by  this  method  highly  satis- 
factory results  from  specimens  from  many  localities,  I  can  confidently  recom- 
mend it  as  an  addition  to  oiu'  modes  of  research. 

"  The  following  directions  wiU  enable  any  one  to  apply  the  process : — Put 
small  lumps  of  the  mass  to  be  examined  into  a  test  tube,  with  enough  of  a 
solution  of  caustic  potassa  or  soda  to  cover  them ;  then  boil  over  a  spuit-lamp 
for  a  few  seconds,  or  a  few  minutes,  as  the  case  may  require.  If  the  solution 
is  sufficiently  strong,  the  masses  wall  rapidly  crumble  to  mud,  which  must  be 
poured  at  once  into  a  large  quantity  of  water,  which,  after  subsidence,  is  re- 
moved by  decantation.  If  the  mass  resists  the  action  of  the  alkaHne  liquor, 
a  still  stronger  solution  should  be  tried,  as,  while  some  specimens  break  up 
instantly  in  a  weak  solution  of  alkali,  others  require  that  it  should  be  of  the 
consistence  of  a  dense  sjTTup.  The  mud  also  should  be  poured  ofi"  as  fast  as 
it  forms,  so  as  to  remain  as  short  a  time  as  possible  in  the  caustic  ley. 

"  The  only  specimens  which  I  have  found  not  to  give  good  results  by  the 


OF  THE  DIATOME.E.  109 

method  above  described,  are  those  from  Tampa  Bay,  Florida,  and  the  infu- 
sorial maris  from  Barbadoes.  In  the  masses  from  Tampa  the  lapidifieation  is 
so  complete  that  the  alkali  destroys  the  shells  before  the  lumps  break  up ; 
and  in  the  case  of  the  Barbadoes  marls  the  cementing  material  is  calcareous, 
and  requires  a  dilute  acid  for  its  removal.  In  applpng  the  above  process, 
one  caution  is  necessary,  which  is  to  thoroughly  Tvash  the  shells  with  luater, 
and  not  with  acids,  as  the  latter  ^\ill  cause  the  deposit  of  a  portion  of  the 
dissolved  silica,  and  materially  injure  the  beauty  of  the  specimens.  A\Tien 
the  washings  are  no  longer  alkaline,  the  specimens  may  be  thoroughly 
cleansed  by  acids,  or  by  the  chlorate  process  described  above." 

A  very  ingenious  plan  of  getting  transverse  and  oblique  sections  of  Dia- 
tomaceous  shells  is  mentioned  by  Schleiden  {Princij)les  of  Botany,  translated 
by  Lanhester,  p.  594),  which  is  precisely  similar  to  that  for  obtaining  trans- 
verse sections  of  hair,  as  fii'st  given  in  Pritchard^s  Microscojnc  Objects.  It 
consists  in  mixing  any  veiy  pure  deposit  ^vith  mucilage,  and,  before  the 
mixtiu-e  is  completely  hardened,  cutting  off  delicate  slices  mth  a  razor  or 
sharp  knife.  The  preservation  of  Diatomeae  for  examination  is,  on  account  of 
their  silicious  composition,  easy ;  and  it  is  only  in  the  case  of  the  stalked,  fila- 
mentous, and  frondose  species  that  any  special  arrangements  are  necessaiy — 
except,  indeed,  those  demanded  in  order  to  mount  them  as  permanent  micro- 
scopic preparations. 

Before  the  structure  of  the  silicious  epiderm  can  be  made  out,  the  endo- 
chrome  of  living  specimens  must  be  destroyed,  which  can  be  effected  by  heat- 
ing the  frustules  on  a  piece  of  talc  or  platinum-foil.  But  where  it  is  wished 
to  preserve  them  in  a  fresh  state,  so  that  theii'  natural  living  appearance  may 
as  far  as  possible  be  retained,  immersion  in  creosote  and  water  is  recom- 
mended by  Mr.  Shadbolt.  Prof  Smith,  however,  finds  distilled  water  supe- 
rior to  any  mixture,  which  is  not  merely  unnecessary,  but  injurious.  "  If," 
.says  the  author  last  mentioned,  "  the  filamentous  and  stipitate  forms  are  not 
mounted  in  a  fresh  state,  the  fnistules  separate  from  each  other,  part  from 
their  stipes,  and  lose  theii'  characteristic  appearance.  To  remedy  these  in- 
conveniences, I  immerse  such  specimens  as  camiot  be  placed  in  cells  when 
freshly  gathered,  in  spirits  of  wine  and  water,  one  part  of  the  former  to  six 
of  the  latter ;  and  their  attachment  to  theii-  stipes  remains  afterwards  undis- 
turbed, unless  violence  be  employed  to  separate  them." 

Fossil,  and  chemically-prepared  and  dried  specimens  are  usually  preserved 
in  Canada  balsam,  which  is  heated  and  rendered  fluid,  so  that  it  enters  within 
the  cavity  of  the  frastules.  The  fluidity  of  the  balsam  is  increased  by  the 
addition  of  a  little  turpentine  or  rectified  spiiit.  The  presence  of  balsam, 
however,  obscures  the  markings  of  the  silicious  epiderm ;  and  it  has  been 
found  better,  where  the  resolution  or  determination  of  the  superficial  sculp- 
turing is  very  dificult,  to  moimt  the  frustules,  in  a  dry  state,  on  a  thin 
object-glass,  and  under  cover  of  a  very  thin  piece.  "  To  prevent  the  admis- 
sion of  moisture,  which  would  ultimately  make  its  way  to  the  object  and  de- 
stroy its  value,  it  is  indispensable  that  the  cover  should  be  cemented  to  the 
thin  glass  below."  (Syno2)s.  i.  p.  xxxii.) 

In  a  collection  of  Diatomeae,  we  may,  by  a  magnifier,  such  as  a  Coddington 
lens,  select  certain  specimens  from  the  rest  to  be  moimted.  This  can  be 
effected,  when  the  size  permits,  by  the  projecting  terminal  hairs  of  a  fine 
camel-hair  pencil,  or  by  the  moistened  tip  of  a  needle  ;  but  if  the  sheU  be 
too  minute  for  this,  a  single  stout  hair  or  bristle  wiU  frequently  suffice,  and 
more  satisfactorily  and  readily  if  the  hair  be  split  at  the  end.  Prof.  Eedfem, 
of  Aberdeen,  pointed  out  the  advantage  of  split  hairs  for  the  purpose,  in  a  brief 
communication  to  the  J.  M.  S.  1853,  p.  235.     He  recommends  a  hair,  split 


110  GENERAL  HISTORY  OF  THE  INFUSORIA. 

into  three  to  five  or  six  parts  at  one  extremity,  to  be  fixed  by  the  other  in  a 
piece  of  cork,  and  held  in  a  common  needle-holder.  Such  split  hairs  are  com- 
mon enough  in  an  old  shaving-brush  ;  but  the  divergence  of  the  split  portions 
should  be  so  slight  that,  until  pressed  upon,  the  hair  should  appear  single  and 
unbroken.  He  has  also  found  entii^e  hairs  very  useful  when  set  in  needle- 
holders  in  a  similar  manner.  The  split  haii's  act  like  forceps,  expanding  by 
pressure  so  as  to  embrace  the  object,  and  closing  upon  it  by  their  elasticity 
when  the  pressure  is  withdrawn. 

To  select  certain  portions  of  a  collection  of  Diatomeae  from  others.  Dr. 
Carpenter  gives  these  directions  {The  Microscope,  p.  340)  : — "  Either  of  the 
two  following  modes  may  be  put  in  practice.  A  small  portion  of  the  sedi- 
ment being  taken  up  in  the  dipping-tube,  and  allowed  to  escape  upon  the 
slide,  so  as  to  form  a  long  narrow  Hne  upon  it,  this  is  to  be  examined  with 
the  loAvest  power  with  which  the  object  we  ai'e  in  search  of  can  be  distin- 
guished ;  and  when  one  of  the  specimens  has  been  found,  it  may  be  taken 
up,  if  possible,  on  the  point  of  the  hair,  and  transferred  to  a  new  slide,  to 
which  it  may  be  made  to  adhere  by  first  breathing  on  its  surface.  But  if  it 
be  found  impracticable  thus  to  remove  the  specimens,  on  accoimt  of  their  mi- 
nuteness, they  may  be  pushed  to  one  side  of  the  slide  on  which  they  are 
Ijdng ;  aU  the  remainder  of  the  sediment  which  it  is  not  desired  to  preseiwe 
may  be  washed  off" ;  and  the  objects  may  then  be  pushed  back  into  the  middle 
of  the  slide,  and  mounted  in  any  way  that  may  be  desit^d."  See  Goring  and 
Pritchard's  Microscopic  Illustrations,  Microscopic  Cabinet,  and  Micrographia 
for  much  original  information  on  these  matters. 


OF  THE  PHYTOZOA.  HI 


Sect.  II.— OF  THE  PHYTOZOA. 
(Plates  XVIII.  XIX.  XX.  and  XXVI.) 

The  Beings  included  under  this  Name  :  theik  General  Character. — 
Division  into  Groups  or  Tribes. — The  collection  of  microscopic  beings  we 
would  comprehend  under  the  tenn  Phttozoa  comprises  most  of  the  Anentera 
of  Ehrenberg,  with  the  exception  of  AmoehcBa,  Arcellina,  Dinohryhui,  Bacil- 
laria,  Chstetnna,  Perklinicea,  and  Cyclidina.  After  excluding  these  famihes, 
there  remain  Monadhm,  Cryptomonadina,  Hydromorhut,  Vohocina,  Vibri^ 
onia,  and  Astaskea,  which,  although  they  exhibit  great  diversity  among 
themselves,  nevertheless  have  certain  characters  in  common,  whilst  their 
mutual  differences  in  essential  particulars  of  organization  and  vital  endow- 
ments are  less  than  those  separating  them  from  the  ciliated  animalcules.  On 
the  other  hand,  they— at  least  the  majority — exhibit  very  marked  genuine 
affinities  ^^ith  the  Diatome^  and  Desmidie^  as  plants.  In  point  of  fact, 
these  organisms  stand  on  the  confines  between  the  animal  and  vegetable 
kingdoms, — some  genera  distinctly  belonging  to  the  latter,  others  doubtfully 
to  the  former,  whilst  many  pass  through  such  phases  of  existence  that  at 
one  time  they  assume  the  characters  of  animals,  at  another  those  of  plants. 

This  apparently  mixed  animal  and  vegetable  natui'e  is  expressed  by  the 
term  Phytozoa,  derived  from  two  Greek  words,  signifying  plant-animals. 
Another  term,  used  by  Perty,  viz.  Phytozoida,  is  a  simple  expansion  of  the 
word  Phytozoa,  signifying  literally  Simmsil-liJce  plants.  Cohn  employs  in  its 
stead  the  term  Flagellata,  derived  from  the  locomotive  organ  or  flagellum 
which  most  species  possess,  whilst  others  prefer  the  word  FJaheUifera. 

In  the  opinion  of  the  majority  of  modem  wiiters,  the  Phytozoa  are  in 
general  undistinguishable  fi'om  imicellular  Algse,  among  the  different  families 
of  which  they  consequently  seek  to  distribute  them  ;  and  doubtless  the 
creation  of  such  a  group  is  pui^ely  artificial,  and  cannot  be  admitted  in  any 
attempted  philosophical  or  natural  classification  of  microscopic  organisms. 
However,  since  so  much  uncertainty  and  dispute  still  prevail  on  the^  question 
of  the  animal  or  vegetable  natiu'e  of  very  many,  and  since  our  knowledge  of 
the  phases  of  existence  of  a  large  number  is  so  imperfect,  it  is  reaUy  impos- 
sible to  estabhsh  any  satisfactoiy  classification.  On  this  account,  and  also  to 
bring  together  for  convenience'  sake  a  mass  of  information  respecting  several 
collections  of  beings  enumerated  among  the  Anenterous  Polygastrica  of 
Ehrenberg,  difficult  or  impossible  to  arrange  imder  any  other  heading,  we 
resort  to  this  artificial  division,  and  in  so  doing  have  the  example  of  Perty 
and  other  wiiters.  After  describing  what  can  be  predicated  of  the  Phytozoa 
in  general,  we  shall  find  it  necessary  to  consider  them  under  several  sections 
or  tribes,  by  reason  of  the  differences  which  prevail  among  them  in  form, 
mode  of  growth,  and  other  particulars ;  and  in  speaking  of  each  tribe  shall 
point  out  its  general  affinities  to  the  others,  and  to  any  families  of  Infusoria 
or  of  Algae. 

Figure.  Coverings  of  Phytozoa. — The  Phytozoa  are  of  more  simple 
organization  and  of  less  varied  outline  than  the  ciliated  Protozoa.  In  figure 
they  are  commonly  round,  or  oval,  or  eUiptical,  and  either  present  no  processes, 


112  GENERAL  HISTOEY  OF  THE  INFUSOEIA. 

or  only  an  elongated  neck  bearing  one  or  more  cilia  (JlabeUa)  to  serve  as 
locomotive  organs. 

How  greatly  their  figure  and  size  are  dependent  on  the  external  influence 
of  light,  is  well  shown  by  some  recent  researches  of  Cohn  on  Stephanosphcera 
(Nov.  Act.  Acad.  Curios,  xxvi.  1857).  On  placing  specimens  of  this  organism, 
some  in  transparent  glass  vessels,  others  in  semitransparent  and  green  ones, 
others  in  porcelain,  and  others  again  in  perfectly  opaque  cups,  the  modifica- 
tions in  size  and  figure,  according  to  the  intensity  of  light  they  received, 
were  altogether  incredible.  In  the  opaque  vessels,  where  they  got  Little  light, 
the  green  cells  remained  delicate,  small,  and  widely  dispersed,  whilst  in  the 
transparent  glasses,  under  sunlight,  they  became  many  times  larger  and 
crowded  together,  and  their  figure  fusiform,  irregular,  and  produced  into 
numerous  protoplasmic  processes.  Indeed,  on  placing  two  portions  of  the 
same  collection  of  Stej^hanosj^hcerct-glohes,  the  one  in  a  transparent,  the  other 
in  an  opaque  vessel,  the  swarming  individuals  in  the  two  will  be  found  so 
unlike  that  they  might  be  readily  conceived  to  be  different  species. 

The  outline  is  fixed  where  the  organism  has  a  firm  envelope ;  and  most  of 
the  Phytozoa  have  such  in  one  phase  of  their  existence,  viz.  when  they  undergo 
the  encysting-process.  We  are  not  acquainted  with  the  entire  history  of 
many  genera ;  but  from  what  we  know  of  some,  we  may  argue  by  analogy  of 
all,  that  in  the  earliest  stages  of  existence  these  cellular  organisms  have  no 
distinctly  organized  wall,  although  they  may  have  a  pellicle  derived  from  the 
contact  of  the  protoplasm,  of  which  they  consist,  mth  siuToimding  media, — a 
mere  superficial  induration,  but  no  separable  membrane.  Such  is  true  of  the 
individual  cells  of  Vohox  (XX),  of  Euglena  (XYIII.  45,  46),  and  of  Monads 
(XYIII.  1  to  28)  in  general.  Subsequently  a  cell-wall,  the  primordial  mem- 
brane or  sac,  may  be  produced,  distinct  and  separable  from  the  contained 
substance.  Furthermore,  many  examples  do  not  stop  here,  but  proceed 
to  throw  out  a  second  wall  exterior  to  the  last-named,  separated  frequently 
from  it  by  a  small  interspace,  and  having  a  much  denser  and  firmer  consist- 
ence. The  cell,  or,  as  Prof.  Henfrey  calls  it  in  the  case  of  Pandorina,  the 
gonidimn  (XIX.  61),  encloses  itself,  in  fact,  within  a  cyst  (XIX.  69),  and  in 
so  doing  mostly  alters  its  form  materially,  loses  its  previous  animal  characters, 
becomes  '  still,'  and  at  the  same  time  quaUfied  to  sustain  Hfe  under  various 
adverse  external  influences,  and  to  continue  the  species  by  an  ulterior  act  of 
development.  In  all  this  we  trace  an  exact  parallel  with  the  history  of  the 
spores  of  the  lower  Algae ;  and  there  is  no  question  that  many  of  the  Phytozoa 
are  no  other  than  spores,  sporozoids,  or  zoospores.  Moreover,  it  is  equally  clear 
that  many  Monadina  and  Cryptomonadina  described  by  Ehrenberg  are  but 
two  phases  of  one  and  the  same  organism. 

Not  a  few  Phytozoa  present  an  additional  coveiing  in  the  shape  of  a  muci- 
laginous layer.  This  is  found  in  isolated  species,  as  Protococcus  pluvialis, 
and  generally  in  aU  the  aggregated  forms  ;  indeed,  it  is  the  principal  agent 
in  the  construction  of  the  latter.  It  has  generally  been  assumed  that  this 
mucilaginous  investment  is  an  extracellular  product,  without  a  definite  bound- 
ary ;  but  Cohn  (on  Protoccocus,  R.  S.  1853)  has  a  long  argument  to  prove 
that  the  true  cell  is  represented  by  it,  conjointly  with  the  included,  coloured, 
apparent  cell.  Thus,  he  writes  (p.  531) — ''  Neither  of  these  bodies  are  true, 
perfect  cells,  inasmuch  as  the  fii^st  wants  the  primordial  utricle,  and  the  second 
is  without  the  true  cell-membrane.  The  two  together  would  represent  the 
perfect  cell."  Again,  it  is  stated  in  the  same  page,  "  that  the  internal  globular 
body  is  not  surroimded  by  any  special  cellulose-membrane,  but  only  by  one 
readily  destroyed  by  chemical  or  physical  agency — probably  nothing  more  than 
a  dense  layer  of  protoplasm.     On  the  other  hand,  the  external  membrane. 


OF  THE  PHYTOZOA.  113 

represents  a  true  cell-membrane,  enclosing  between  itself  and  the  coloured 
substance  a  colourless  aqueous  fluid,  probably  pure  or  nearly  pure  water." 
And  in  the  subsequent  considerations  of  this  structiu-e,  Cohn  appears  to  arrive 
at  the  conviction  that  the  internal  coloiu-ed  body  generally  spoken  of  as  the 
cell,  the  actual  unicellular  organism,  represents  the  nucleus  of  a  cell,  of  which 
the  periphery  of  the  mucous  envelope  is  the  boundary.  In  this  interpretation 
of  the  natiu'e  of  the  mucilaginous  envelope,  Prof.  Williamson  concm\s.  Indeed 
this  accurate  observer  proceeds,  further,  to  show  that  there  is  in  the  case  of 
Volvox  a  true  enclosing  delicate  membrane  to  each  cell,  and  that  the  hexa- 
gonal form  is  owing  to  the  mutual  pressui^e  of  the  aggregated  cells  (PI. 
XX.  38).  In  aggregate  forms,  such  as  Volvox,  Goniiun,  Fandorlna,  &c.,  an 
additional  common  external  membrane  would  seem  to  be  tlu^own  out,  to  unite 
together  into  one  symmetrical  whole  the  various  members  of  the  colony. 
Perhaps  it  should  be  rather  called  a  pellicle  than  a  membrane,  seeing  that  its 
independent  existence  as  a  separable  structm^e  cannot  be  demonstrated :  yet 
it  has  a  power  of  resistance ;  for  when  external  force  is  applied  to  a  globe  of 
Volvox,  the  surface,  though  at  first  depressed,  presently  recovers  itself  by  an 
innate  elasticity ;  and  in  the  case  of  Pandorina  it  seems  so  resistant  and  firm 
that  it  does  not  indent  on  pressure  (XIX.  61 ). 

Cell-coxtexts. — The  fluid  distending  the  mucilaginous  envelope  around 
most  Phytozoa,  in  one  or  other  stage  of  being,  is,  according  to  Cohn,  as  above 
noticed,  probably  pure  water.  This  opinion  Prof.  Williamson  does  not  enter- 
tain; for  he  says  (J.  M.  S.  1853,  p.  bb)  "it  is  apparently  mucilage.  In  a 
preparation  in  which  a  nimiber  of  these  objects  [of  Volvox']  are  mounted  in 
dilute  alcohol,  this  gummy  matter  has  changed  to  a  bro-svn  coloiu^  and  refused 
to  mingle  ^vith  the  alcohol,  as  would  be  the  case  supposing  it  to  be  mucila- 
ginous.     This  proves  that  it  is  a  true  secretion  from  the  organism,  and  not 

merely  water  absorbed  by  endosmosis The  secretion  itself  is,  perhaps,  little 

more  than  a  diluted  condition  of  the  same  gum  as  that  which  is  more  or  less 
completely  converted  into  cellulose  in  the  various  investing  membranes." 

The  central  globule,  or  the  whole  recognized  organism  where  a  mucilaginous 
envelope  is  not  present,  consists  of  a  mass  of  protoplasm.  At  fii'st  it  is  homo- 
geneous and  without  colour ;  subsequently  it  becomes  generally  coloured  and 
granular  ;  but  very  shortly  the  included  matters  gather  together  into  a  sort  of 
layer  subjacent  to  the  surface,  and  leave  the  central  part  clear,  sometimes  so 
completely  so  that  it  assumes  the  appearance  of  a  vacuole.  This  substance 
moreover  has  the  property  of  contractility  inherent  in  it,  and  would  seem,  in 
all  essential  circumstances,  homologous  with  the  simple  contractile  matter — 
the  sarcode  of  animalcules.  Like  the  latter,  it  may  hollow  itself  out  into 
vacuoles  at  any  part ;  and  such,  says  Cohn  {R.  S.  p.  535),  "  are  present  in  all 
yoimg  cells,  and  play  a  considerable  part  in  cell-division  and  the  sap- currents." 
The  property  of  contractility  is  singularly  displayed  in  the  case  of  the  actively 
moving  zoospores  or  sporozoids  of  the  Algae,  and  in  the  motile  form  of  Proto- 
coccus, — {.  e.  in  every  instance  where,  from  the  absence  of  more  or  less  inelastic 
membranes,  it  can  exhibit  itself.  The  vacuoles  of  the  protoplasm  occur  in 
varying  numbers,  and  change  or  disappear  from  time  to  time :  within  they 
contain  an  aqueous  fluid. 

The  contractile  protoplasm  is  itself  colourless ;  yet,  except  in  the  earliest 
stages  of  development,  it  partakes  of  a  green  or  a  red  colour,  or  of  both  these 
coloui's  together,  save  in  one  spot,  which  in  oblong  forms  is  situated  at  one 
end,  and  in  the  projection  or  beak  (proboscis,  Ehr.,  or  rostellum)  extending 
from  the  anterior  extremity.  "  It  appears,"  says  Cohn  {R.  S.  p.  536),  "  as 
a  dehcate,  almost  imperceptible  layer  constituting  the  outer  boundary  of  the 
coloured  primordial  ceU,  the  peripheiy  of  which  then  becomes  shai7)ly  de- 


114  GENEEAL  HISTORY  OF  THE  IIs^FUSORIA. 

fined,  and,  as  it  were,  surrounded  by  a  delicate  transparent  membrane." 
The  green  colour  is  due  to  chlorophyll  vesicles  and  granules,  either  diffused 
or  collected  in  a  layer  just  beneath  the  surface.  Among  other  contents  are 
also  starch-granules  without  colour,  and  very  frequently  globules  of  oil. 

Green  or  red  may  exist  alone  :  but  more  frequently  green  prevails ;  and  the 
red  pigment,  sometimes  termed  erythrin  or  erytliropliyU,  is  seen  only  at  one 
spot,  occasionally  at  the  centre,  but  usually  on  one  side  of  it,  or  at  one  ex- 
tremity: when  occupying  the  position  last-named,  it  was  looked  upon  by 
Ehrenberg  as  an  eye-speck  or  organ  of  vision. 

Although,  as  Cohn  (op.  cit.  U.S.  p.  528)  tells  us,  the  green  and  red  coloui'- 
ing  matters  differ  in  chemical  and  physical  conditions,  yet  the  one  passes  into 
the  other.  The  red  or  bro^vnish-red  colour  is  formed  when  the  cells  become 
drier  ;  but  neither  deficiency  of  water  nor  the  influence  of  light  appears  to  be 
the  exclusive  cause  of  the  transition.  It  is  especially  in  the  transition  to  red 
that  vesicles  of  an  oUy  aspect  make  their  appearance.  Indeed,  that  oil  is  really 
formed,  is  supported  both  by  analogy  yviih  the  spores  of  many  Algae  which 
clearly  secrete  that  substance,  and  by  the  vesicles  in  question  having  a  similar 
refraction  to  oil,  and  behaving  like  it  \\'ith  alcohol  and  ether.  "  The  forma- 
tion of  fixed  oil,"  says  Braun  {Rejuv.,  R.  S.  p.  200),  "  is  intimately  connected 
Tvith  that  of  starch  in  the  economy  of  ceU-Hfe  ;  its  appearance,  in  like  manner, 
announces  the  repose  of  age  in  cell-hfe ;  its  disappearance,  the  beginning  of 
rejuvenescence.  We  meet  with  fixed  oil  in  the  cells,  either  mixed  with  starch, 
substituted  for  it,  or  gradually  displacing  it ;  its  occiuTcnce  is  perhaps  still 
more  general  than  that  of  starch ....  Like  the  latter,  it  is  met  with  in  greatest 
abimdance  in  those  parts  in  which  vegetation  is  destined  to  rest  and  to  await 
a  future  re-awakening  ;"  and  such  are  the  resting-cells  of  Phytozoa,  in  which 
a  red  colom-  predominates  or  exists  alone.  Braun  furnishes  an  illustration  of 
this  in  his  remarks  on  Clilamydomonas  duiing  its  sleeping  or  resting  state 
(op.  cit.  p.  214).  The  opinion, moreover,  that  the  so-called  redeye-specks  of 
Phytozoa  are  no  other  than  drops  of  oil,  is  shared  by  Perty  (j).  117)  and  by 
Nageli  (Emzell.  AJg.  p.  9). 

Speaking  of  Protococciis,  Cohn  remarks  (op.  cit.  p.  o26),  "  The  red  and  the 
green  portions  of  the  contents  appear  to  be  of  equal  physiological  importance 
....  AMien  still  or  motile  cells  are  brought  into  contact  with  a  veiy  weak 
watery  solution  of  iodine,  they  become  internally,  in  most  parts,  of  an  intense 
violet  or  blue  colour."  Yet  he  does  not  believe  this  coloui'  to  depend,  in 
all  instances,  upon  starch ;  for  the  red  contents  are  equally  coloured  blue,  and 
he  therefore  sui'mises  there  may  be  some  other  substance  besides  starch  ex- 
hibiting the  same  reaction  vidth  iodine. 

Besides  diffused  chlorophyll -particles,  to  which  the  green  coloiu'is  due,  one, 
two,  three,  or  more  large  nuclear-hke  vesicles  exist  in  Phytozoa — indeed,  in 
unicellular  plants  generally — described  by  Xageli  under  the  name  of  '  clihro- 
phyJl  utricles  or  vesicles.^  The  number  of  such  in  any  genus  seems  commonly 
to  be  constant :  thus,  in  StejphanosplicBra  there  are  two  ;  in  Gonium  only  one. 
However,  they  are  occasionally  absent,  chiefly  so  m  more  minute  examples. 
In  Protococcus  (Chlamydococcus),  Cohn  says  they  occur  piincipaUy  in  the  green 
cells,  to  the  number  of  one,  two,  three  or  more,  having  the  appearance  of 
minute  green  rings,  about  0-002'"  in  diameter — the  interior  being  sometimes 
darker,  at  others  more  clear,  and  frequently  almost  opake.  Niigeli  regarded 
them  as  minute  membranous  vesicles,  containing  a  mucus  coloured  by  chloro- 
phyll. Cohn  imagined  that  in  Protococcus  they  stood  in  connexion  with  the 
division  of  the  cell,  but  could  not  determine  with  certainty  that  their  number 
corresponded  with  that  of  the  secondary  cells.  Kiitzing  looked  upon  them 
as  gonidia  or  cell-nuclei,  concerned  in  the  propagation  of  the  individual. 


OF  THE  PHYTOZOA.  115 

Ehrenberg  entertained  a  similar  notion,  and  called  them  the  testes.  ^'  Caustic 
potash,"  says  Cohn  (A.  N.  H.  1852,  x.  p.  340),  "which  destroys  the  rest  of  the 
contents  of  the  piimordial  cells,  makes  the  chlorophyll-utricles  of  Stephano- 
sphctira  show  themselves  more  distinctly  as  hollow  rings  surroimded  by  a  rather 
granular  membrane  ;  iodine  coloiu's  them  deep  \'iolet,  which  leads  to  the  con- 
clusion of  the  presence  of  starch."  Iodine  sometimes,  however,  produces  a  deep 
brown  tint  (Cohn,  R.  S.  p.  529),  due,  we  may  suppose,  to  an  idterior  meta- 
morphosis of  the  starch,  as  it  is  itself  a  transitional  condition  of  chlorophyll. 

Another  stnicture  met  ^vith  among  the  contents  of  some  of  the  Phytozoa 
is  the  contractile  vesicle  or  sac.  This  sac  has  been  noticed  in  Volvox,  Gonium, 
Pandorina,  Chilomonas,  Cryptomonas,  and  in  Chlamydomonas,  and  its  rhyth- 
mical contractions  observed  (XIX.  16,  33  ;  XX.  40,  41).  In  Stephanosphcp.ra 
a  similar  vesicle  was  seen  by  Cohn,  but  its  contractility  not  detected :  so  in 
Astasia,  Euglena  (XYIII.),  and  Polytoma  (XX.  1,  2),  a  clear  sac-like  space 
presents  itself  at  the  anterior  extremity,  immediately  beneath  the  surface  ; 
but  its  alternate  expansion  and  contraction  have  not  been  ^vitnessed. 

A  nucleus  is  detected  in  Euglena,  Astasia,  Polytoma  (XX.  1,  2,  3),  and 
others  in  which  an  animal  nature  predominates.  Even  among  the  vegetable 
genera  Volvooc,  Pandorina,  and  Gonium  (XIX.  32,  34,  61),  most  writers,  as 
already  seen,  seem  disposed  to  view  the  constant  chlorophyll-vesicles  as  of 
a  nuclear  character.  In  Gonium,  indeed,  Cohn  (Entw.  p.  178)  describes  only 
one  such  vesicle,  which  seems  to  demonstrate  its  nuclear  natiu^e  by  breaking 
up,  duiing  the  process  of  fission,  into  as  many  parts  as  the  primordial  cell 
itself.  Braun  (op),  cit.  p.  174,  in  note)  mentions  his  observation  of  a  central 
vesicle  or  nucleus  in  Chlamydococcus  (XIX.  22,  24,  26),  and  remarks,  "  in 
most  of  the  true  Pabnellacese  there  is  a  chlorophYll-vesicle  in  the  centre  of 
the  ceU." 

The  appearance  of  the  cells  of  Phytozoa  is  much  modified  by  variations  in 
the  relative  quantity  or  in  the  arrangement  and  colour  of  the  contents,  so  much 
so  indeed  that  such  varieties  have  been  described  as  different  species  or  even 
as  different  genera.  Thus  the  accidental  presence  of  a  red  spot,  called  an  eye- 
speck,  or  the  occurrence  of  a  red  central  space,  have  had  a  specific  importance 
wi^ongly  attached  to  them.  The  inutility  of  characters  deduced  from  the 
disposition  and  appearance  of  the  cell-contents,  or  from  the  figure,  is  further 
shown  when  the  effects  of  external  agents — of  temperature,  of  the  abundance 
or  deficiency  of  nutritive  matters,  of  hght,  &c. — are  taken  into  account ;  and 
it  becomes  even  stiU  more  evident  when  the  changes  of  form  one  and  the 
same  being  may  undergo  are  duly  considered. 

In  a  previous  page  it  has  been  stated  that  in  the  earliest  phase  of  existence, 
when  the  future  cell  is  but  one  of  several  macrogonidia  within  its  mother-cell, 
the  protoplasm  of  which  it  consists  is  unenclosed  by  a  membrane — has  no  cell- 
wall.  But  it  would  seem  that  a  ceU-membrane  is  wanting  even  at  maturity 
in  some  genera,  for  example,  in  Step7ianosp>hcera  ;  for  Cohn  writes  (A.  N.  H. 
1852,  x.  p.  326),  "  This  is  not  only  made  evident  by  the  multifold  changes 
of  form  which  they  undergo  in  the  coui^se  of  vegetation,  and  by  the  fihform 
prolongations  and  ramifications  which  are  produced  directly  from  theii'  sub- 
stance (XIX.  38,  39-53),  but  is  clearly  shown  by  the  transformations  which 
the  primordial  cells  pass  through  in  consequence  of  external  influences. 
Under  certain  circumstances  namely,  the  filiform  processes  may  be  retracted, 
being  torn  away  from  the  envelope -ceU  and  taken  up  into  the  substance  of  the 
primordial  cells  ;  the  produced  ends  of  the  primordial  cells  also  disappear,  the 
latter  becoming  rounded  off  into  theii'  original  spherical  or  short  cyhndiical 
form.  Such  a  change  would  be  impossible  if  the  primordial  cells  were  sur- 
rounded by  a  rigid  membrane,  such  as  that  of  the  envelope-cell  for  example." 

i2 


116  GEIS^ERAL  HISTORY  OF  THE  INFUSORIA. 

According  to  Prof.  Henfrey,  the  primordial  cells  or  gonidia  of  Pandoinna 
(XIX.  59-63),  and  also,  in  the  opinion  of  many,  the  Euglence  (XVIII.  45-48), 
are  similarly  undefended. 

The  internal  globular  coloured  body  of  the  motile  form  of  Protococcus  is  in 
the  same  state.  Thus  Cohn  {R.  S.  p.  531)  points  out  that  although  this 
body  has  a  sharply  defined  outline,  yet,  "  either  by  mechanical  means,  or  by 
chemical  reagents,  the  internal  globular  mass  may  suddenly  be  made  to  lose 
its  contour,  and  to  sjjread  so  as  entirely  to  fill  the  ca\ity  of  the  colourless 
envelope.  From  which  it  would  appear  that  the  internal  globular  body  is 
not  surrounded  by  any  special  cellulose  membrane,  but  only  by  one  readily 
destroyed  by  chemical  or  physical  agency — probably  nothing  more  than  a 
dense  layer  of  protoplasm." 

In  the  case  of  Volvox  the  cells  originate  without  an  enclosing  membrane ; 
but  after  the  appearance  of  the  red  spot,  a  dehcate  one  shows  itself,  and 
extends  at  difierent  points  into  the  connecting  thread-like  processes  (XX.  37, 
39,  41).  So  in  Gon'ium  we  may  presimie  the  jDrimordial  cells  to  be  originally 
naked,  although  Cohn  has  not  remarked  this  fact,  but  confined  himself  to 
describing  the  matui^e  ceUs  (XIX.  32,  34),  which  have  an  enclosing  wall  of 
cellulose  (Enhv.  pp.  175, 1 76).  Lastly,  in  the  '  still'  form  of  Protococcus  a  special 
membrane  invests  the  protoplasmic  gonidium.  In  Goniiini  (XIX.  34),  and  in 
Volvox  (XX.  37,  39,  40),  filiform  prolongations  extend  between  the  several 
cells  in  the  compound  organism  ;  in  Stephanospluera  similar  processes  are 
given  ofi"  at  the  opposite  poles  of  the  cells,  and  are  consequently  not  inter- 
current (XIX.  39).  Prof.  Williamson  has  in  the  case  of  Volvox  offered  the 
best  explanation  of  these  threads,  wliich  have  by  some  been  supposed  inter- 
communicating canals.  He  first  makes  good  his  opinion  that  the  green  cell- 
Kke  organism  represents  the  nucleus  of  a  cell,  the  wall  of  which  is  separated 
from  it  by  a  greater  or  less  space ;  and  then  he  compares  the  processes  in 
question  with  the  fihform  extensions  fi'om  the  nucleus  which  are  met  with 
in  many  vegetable  cells,  suspending  that  organ  in  the  centre.  In  the  early 
stage  of  the  cell,  the  protoplasmic  substance  fills  up  more  or  less  completely 
the  cell- wall  (XX.  42,  44)  :  by-and-by  the  latter  becomes  outstretched  from 
it  by  a  sort  of  di'opsical  efiusion  within  it  (XX.  37) ;  but  as  the  protoplasmic 
nucleus  has  contracted  adhesions  at  difii'erent  parts,  it  becomes  di'awn  out  from 
the  adherent  points  into  thi^ead-hke  processes  (XX.  39,  40,  45),  which  grow 
more  and  more  filiform  in  proportion  as  the  cell- wall  expands.  This  expla- 
nation (agreeing  in  every  particular  with  the  observed  phenomena  of  cell- 
growth)  being  accepted,  it  follows  that  these  elongations  are  bounded  by  the 
particular  cell- wall  to  which  they  belong,  and  are  not  continuous  with  those 
of  adjoining  cells.  The  processes  of  Volvox  are  therefore  ofi'-shoots  of  the 
protoplasm  of  which  each  cell  or  gonidium  consists  ;  they  are  given  ofi"  before 
any  enclosing  wall  or  peUicle  appears,  and  wliilst  that  substance  is  still  duc- 
tile, and  they  disappear  on  the  commencement  of  the  process  of  development, 
whether  of  macrogonidia  or  of  microgonidia,  and  whether  mth  or  without  the 
process  of  encysting. 

In  the  case  of  Gonium,  Cohn  gives  {Entw.  p.  176)  a  different  account  of 
the  connecting  bands.  It  will  be  remembered  that  in  this  genus  that  ob- 
server indicates  an  enclosing  cellulose  membrane  to  each  cell  or  gonidimn. 
Now  this  cell  does  not  closely  invest  the  protoplasmic  substance  at  all  points, 
but  is  so  separated  as  to  produce  a  hexagonal  cell-wall  aroimd  it,  from  each 
angle  of  wliich  the  membrane  is  produced  in  a  tubular  form,  and  joins  mth 
a  similar  process  coming  from  the  angle  of  an  adjoining  cell  (XIX.  32,  34). 
Hence  each  process  of  the  membrane  has  a  double  outline,  and  is  in  fact  a 
tube,  only  that  its  interior  must  be  presumed  to  be  shut-off  from  that  vdi\\ 


OF  THE  PHYTOZOA.  117 

which  it  joins,  by  a  septum  representing  the  divisional  membrane  of  each  of 
the  contiguous  cells.  The  state  of  things  here  is  therefore  quite  different 
from  that  in  Volvox :  for  in  the  latter  the  cell-membrane  is  widely  detached 
from  the  protoplasmic  nucleus,  but  the  adjoining  cells  are  adherent  at  all 
points ;  the  intercurrent  thi^eads  are  therefore  v\dthin  the  cells,  and  uphold 
an  attachment  between  the  nucleus  and  the  cell- wall, — whilst  in  Gonium  the 
contrary  obtains :  the  cells  themselves  are  not  in  apposition,  but  held  together 
by  a  tubular  extension  from  each  angle ;  and  the  nuclear  protoplasm  within 
nearly  fills  the  cell-cavdt}',  and  has  no  bands  uniting  it  v\dth  the  waU — in 
fine,  the  intercurrent  processes  of  Gonium  and  of  Volvox  are  not  homologous. 

Besides  the  wall  and  processes  just  described,  calculated  to  give  strength 
and  resistance  to  the  organisms,  there  are  also  the  long  cilia  or  filiform  ap- 
pendages known  as  filaments,  flabella,  or  flageUa,  seen  at  one  extremity  of 
most  Phytozoa,  derived  from  the  protoplasmic  mass.  To  these  are  entirely 
or  chiefly  due  the  locomotive  powers  of  these  beings ;  they  also  act  the  part 
of  rudders  in  turning  them  on  themselves,  and  in  directing  them  hither  and 
thither.  They  do  not  belong  to  the  class  of  vibratile  cilia,  but  are  larger, 
filiform  or  whip-like,  and  have  an  undulating  lashing  movement.  In  some 
cases  they  are  many  times  longer  than  the  organism  to  which  they  are  attached 
(XVIII.  15,  21,  22) ;  and  when  two,  as  more  frequently  happens,  are  pre- 
sent, they  wiU  often  cross  and  intertwine.  At  times,  in  elongated  forms, 
they  appear  to  be  the  mere  terminations  of  the  tapering-Hke  extremity  or 
neck ;  but  the  rule  is,  they  do  not  proceed  from  the  apex  itself,  but  from  one 
side  of  it.  Whei'e  the  species  is  encased  in  a  fii^m  integument,  separated  by 
an  interval  from  the  central  protoplasm,  the  filaments  actually  extend  from 
the  latter  and  perforate  the  enclosed  case  ;  in  which,  particularly  when  these 
processes  are  fallen  away,  their  points  of  issue  are  occasionally  to  be  detected 
b}^  depressions  or  by  pores.  Duiing  frequent  rapid  movements  these  fila- 
ments are  not  to  be  seen  ;  but  when  the  motion  is  more  gentle,  or  they  are 
at  rest,  or  otherwise  when  colouiing  matter  is  mixed  mth  the  water,  they 
generally  become  visible.  Even  when  their  existence  has  not  been  noticed 
duiing  life,  it  may  be  sometimes  demonstrated  after  the  diying  up  of  the 
being,  by  the  streak  left  upon  the  glass  where  it  rested.  Where  more  than 
one  or  two  filaments  are  present,  their  whirling,  and  the  consequent  agitation 
of  the  fluid  about  them,  makes  their  existence  apparent. 

The  number  of  filaments  in  Phytozoa  varies.  Two  is  the  prevailing  number, 
which  may  or  may  not  be  of  equal  length ;  but  in  not  a  few  genera  only  one 
is  found,  e.  g.  in  Euglena,  Monas,  and  Chilomonas, — whilst  in  others  more  than 
two  may  be  counted,  situated  together  anteriorly,  or  some  in  front  and  others 
behind.  Where  two  are  present  anteriorly,  it  is  not  an  uncommon  arrange- 
ment for  one  to  extend  in  the  direction  of  the  long  axis  of  the  body,  whilst 
the  other  trails  behind  (XYIII.  12,  22,  23). 

MovEiiEXTs  OF  Phytozoa. — The  motion  of  many  Phytozoa  is  but  slow, 
and  rarely  intermitted ;  in  others  it  is  more  rapid  and  varied.  It  wiU  be 
modified  by  the  figui-e  of  the  organism  and  by  the  degree  of  firmness  of  its 
waUs,  with  which  it  stands  in  inverse  proportion.  In  Euglena  the  move- 
ments are  extremely  varied  and  lively :  the  being  is  unrestricted  in  its 
movements  by  an  integument,  and  the  contractile  protoplasm  has  full  scope ; 
it  is,  in  fact,  in  the  condition  of  swarming  gonidia,  unenclosed  by  a  wall  of 
cellulose.  In  many  species  of  Monas  and  Bodo  (Cercomonas),  the  motion  is 
irregular  and  peculiar ;  it  may  be  oscillating  or  rolling,  at  times  leaping,  at 
others  backward.  Among  the  Vibrionia  (XYIII.  57-69),  an  oscillating 
spiral  movement  is  a  common  characteristic,  and  either  end  may  be  advanced. 
The  revohing  rolling  motion  of   Volvocinece  has  for  many  years  attracted 


118  GENEKAL  HISTORY  OF  THE  KfFUSORIA. 

attention,  and  for  a  long  time  was  deemed  sufficient  proof  of  the  animality 
of  the  beings  exhibiting  it.  It  is  the  consequence  of  the  play  of  the  ciliary 
filaments  of  each  of  the  component  cells  of  the  aggregate  organism,  which 
project  beyond  the  common  envelope :  it  consists  in  a  revolution  on  the  axis, 
and  a  simultaneous  onward  movement — not,  however,  in  a  straight  course, 
but  in  an  iiTcgular  one,  representing  a  spiral  or  series  of  curves.  "  The 
collective  idea  of  such  motions,"  says  Cohn  (A.  N.  H.  1852,  x.  p.  328),  "is 
best  represented  by  the  coiu'se  described  by  a  top,  which  rims  through  the  most 
varied  curves,  while  at  the  same  time  constantly  revohing  on  its  axis." 

jS'ageh.  (as  quoted  in  J.  M.  S.  i.  p.  198)  remarks  of  swarm-cells  (zoospores), 
which  many  Monads  imdoubtedly  are,  that  "  under  the  microscope  the  motion 
appears  very  rapid,  somewhat  of  an  infusorial  character,  consisting  in  a  con- 
tinual progression,  in  which  the  hyahne  narrower  extremity  is  usually  in 
front,  and  the  cell  is  continually  turning  on  its  long  axis.  Although  the 
swarming  bears  a  resemblance  to  the  motion  of  Lifusoria  (i.  e.  of  Ciliated 
Protozoa),  it  clearly  wants  the  s23ontaneity  of  the  latter.  The  Infusoria 
advance,  spring  back,  turn  round,  retui-n,  all  spontaneously ;  the  swarm- 
spores  piu'sue  a  imiform  and,  for  the  most  part,  pretty  straight  com^se,  de- 
\iating  from  it,  or  turning  round  only  upon  meeting  an  obstacle,  impinging 
upon  which  they  are  diverted  into  another  direction."  To  this  account 
Siebold  {Joe.  cit.  p.  201)  adds  that  the  spores  do  not  retreat,  as  if  frightened, 
like  the  Infusoria,  when  they  strike  against  an  object,  but  "  remain  close  to 
it,  and  continue  their  motions  according  to  the  number  and  arrangement  of 
their  ciliary  apparatus,  in  a  rotatory  or  \4bratory  way  for  a  little  time  longer, 
as  if  they  aimed  at  overcoming  the  obstacle  by  force,  until  at  last,  probably  in 
consequence  of  the  death  of  the  cilia,  they  become  still.and  germination  goes  on. 
...  The  movements  of  the  swarm- spores  in  general  have  only  a  short  diu'ation. 
After  the  spores  have  come  to  a  state  of  rest,  they  usually  become  attached 
by  the  hyaline  ciliated  extremity,  and  the  locomotive  faculty  is  for  ever  lost." 
In  the  aggregated  families  the  process  of  reproduction  is  ever  going  on  in 
some  members  of  the  colony,  and  the  movements  are  kept  up  much  longer. 
Braim  {Bejuv.,  R.  S.  p.  212)  represents  Chlamydococcus  as  enjoying  a  longer 
duration  of  motion  than  is  iLsual  with  the  swarming  gonidia  of  Algee,  whilst 
Protococcus  viridis  forms  an  intermediate  link  in  this  respect  between  it  and 
the  Volvodnece.  The  kind  of  movement,  he  adds,  is  essentially  the  same  in 
these  organisms  as  in  all  active  gonidia,  namely  an  uninternipted  revolution 
round  the  long  axis,  combined  with  an  advance  towards  the  side  of  the 
ciliated  point.  It  is,  indeed,  in  the  swarming  movement  of  gonidia  and 
spermatozoida  that  the  phenomena  of  motion  are  most  striking,  "that  is,  in 
cells  which  are  either  yet  without  their  cclbilose  coating,  or  which  never 
acquii'e  one." 

Cohn  {B.  S.  p.  558)  states  generally  that,  "  leaving  out  of  the  question 
the  more  highly  organized  Infusoria  furnished  with  a  manifest  mouth  and 
a^sophagus,  the  motion  of  a  large  part  of  the  Anentera  (Ehr.),  the  Astoma  (Sie- 
bold), is  not  essentially  different  from  that  of  the  zoospores  of  certain  Algae." 
Likewise,  in  his  description  of  Gonium  (Entiu.  p.  180),  he  observes  that  the 
movements  of  this  organism  resemble  in  every  particular  those  of  Stephano- 
sjjlicera,  Chlamydococcus,  and  other  swarming- cells,  "  which  certainly  do  not 
bear  at  all  the  character  of  pui^posing,  conscious  volition,  but  appear  as  an 
acti\T.ty  determined  not  by  any  external  causes,  but  by  internal  causes  in  the 
organization  and  vital  processes."  {A.  N.  H.  1852,  x.  p.  328.) 

The  character  of  the  locomotion  of  Phytozoa  may  be  described  in  brief  as 
'  automatic ;'  accepting  that  term  as  physiologists  now  agree  to  do,  to  distin- 
guish such  motion  from  the  voluntary  movements  of  animals.     It  cannot  be 


OF  THE  PHYTOZOA.  119 

voluntary,  or  the  result  of  volition,  any  more  than  the  marvellous  motion  of 
the  leaves  of  Dioncea  rnuscipula. 

Peocess  of  Nutrition-. — The  process  of  nutrition  of  Phytozoa  is  of  the 
most  simple  kind ;  and  no  valid  evidence  can  be  adduced  in  proof  of  the  com- 
plex polygastric  organization  represented  by  Ehrenberg.  In  fact,  an  apparatus 
of  stomach-sacs  could  not,  by  any  analogy,  be  presumed  in  a  set  of  beings 
destitute  of  mouths ;  and  Ehi^enberg  was  unable  to  demonstrate,  even  to  his 
own  satisfaction,  an  oral  aperture,  except  in  a  very  doubtful  manner  and  in 
a  very  few  instances.  What  he  took  to  be  gastric  cells  are  no  other  than 
vacuoles  and  clear  vesicles — sometimes  the  chlorophyll-cells ;  the  last,  how- 
ever, were  more  commonly  assumed  to  be  '  testes.'  To  support  his  behef  in 
the  presence  of  stomachs,  and  also  of  a  mouth  at  the  anterior  clear  space, 
particularly  Avhere  there  is  a  j^rojection  of  the  protoplasmic  mass,  the  Berlin 
natm'alist  appealed  T\ith  most  confidence  to  his  experiments  in  feeding  with 
coloured  substances.  By  this  means  he  believed  he  demonstrated  such 
organs  in  some  Monadina, — but  so  rarely,  amid  a  large  number  submitted  to 
experiment,  and  moreover  in  so  few  species,  that  much  weight  could  not  be 
attached  to  the  result,  especially  when  it  is  considered  how  many  difficulties 
and  doubts  must  arise  where  such  very  minute  beings  are  concerned.  Allow- 
ing that  particles  of  colour  actually  entered  within  the  interior,  and  Avere  not 
merely  adherent  (a  question  which  the  magnifying  powers  of  the  instrument 
Ehrenberg  used  could  scarcely  determine),  it  is  even  then  much  more  rational 
to  suppose  that  their  entrance  was  by  mere  mechanical  causes  (by  pressure 
or  the  like),  than  by  the  medium  of  a  mouth.  This  interpretation  is  adopted 
both  by  Perty  and  Leuckart,  who  describe  the  introduction  of  such  particles 
as  possible,  although,  indeed,  exceedingly  rare  in  the  more  clearly  vegetable 
structui'es,  the  Diatomeae.  The  former  mentions  {op.  cit.  p.  61)  three  in- 
stances in  which  he  encountered  foreign  particles  Avithin  the  substance  of 
Phytozoa ;  but  these  would,  instead  of  supporting,  be  really  opposed  to  the 
polygastric  hypothesis.  For  instance,  he  discovered  in  a  Peronema  a  species 
of  Bacillaria  as  large  as  itself,  and  consequently  not  containable  within  one 
of  the  supposed  gastric  cells. 

In  the  case  of  the  soft,  illoricated  minute  Monadina,  into  which  fine  particles 
have  found  their  way,  it  is  to  be  remembered  that  they  are  mere  masses  of 
yielding  protoplasm  unprotected  by  a  cuticle ;  and  further,  we  may,  along 
Avith  Perty,  reasonably  presume  that,  in  some  examples  of  the  entrance  of 
external  matters,  it  has  been  effected  much  in  the  same  way  as  mth  the 
Amoebce,  by  the  soft  substance  overlying  and  then  surroimding  them. 

If  a  mouth  and  stomachs  have  no  existence,  it  follows  that  nutrition  must 
be  effected  by  imbibition — by  endosmotic  and  exosmotic  action — just  as  in  any 
simple  vegetable  or  animal  cells.  Perty  (op),  cit.  p.  62)  adduces  an  experiment 
showing  that,  to  some  Phytozoa  at  least,  water  rich  in  nutritive  organic 
material  is  necessary  to  their  complete  and  healthy  development ;  for  when 
taken  fi'om  such  water  and  placed  in  other  quite  pure,  they  dwindled  in  size, 
although,  curiously  enough,  they  at  the  same  time  became  more  active. 

To  complete  what  we  have  to  say  of  their  vital  endowments  (irrespective, 
that  is,  of  the  reproductive  functions),  the  Phytozoa  seek  the  light ;  and  aU 
their  nutritive  acts  are  carried  on  more  actively  under  its  influence.  The 
only  exception  is  when,  in  the  process  of  propagation,  they  are  about  to  pass 
into  the  '  stiU '  condition  and  to  become  encysted ;  then  they  eschew  the  light, 
sink  out  of  sight,  and  recede  to  the  bottom,  or  under  cover  of  aquatic  plants 
or  of  theii'  debris.  Under  the  influence  of  light  they  exhale  oxygen  gas, 
and  the  green  colour  is  especially  developed, — whilst  when  kept  in  the  dark 
they  lose  colour,  become  pale,  and  present  few  chlorophyll-particles.     The 


120  GENEEAL  HISTORY  OF  THE  INFUSOEIA. 

intensity  of  Kght  may  be  too  great,  and  destroy  life ;  and  a  great  elevation  of 
temperature  is  less  favom^able  to  vital  activity  than  a  moderate  one.  Cold 
retards  vital  action,  and  if  considerable,  arrests  it,  except  in  the  case  of  the 
encysted  beings,  which  are  so  modified  by  natiii'e  as  to  resist  its  injmioiis 
influence;  these  consequently  persist  through  the  winter  when  the  motile 
forms  are  cut  off,  and  in  the  coming  spiing  bm\st  forth  into  life.  The  same 
provision  which  imparts  to  the  encysted  organisms  a  tolerance  of  cold,  enables 
them  also  to  withstand  the  effects  of  evaporation,  which  to  the  unprotected 
motile  varieties  is  speedily  destructive,  unless,  indeed,  so  gradual  as  to  allow 
them  time  to  pass  into  the  '  still '  form. 

Starch  or  cellulose  may  be  detected  chemically  in  the  great  majority  of  the 
Phytozoa;  and  even  where  iodine  fails  to  produce  the  characteiistic  blue 
colour  during  Hfe,  it  will  at  times  act  strongly  when  a  breaking-up  of  the 
contents  follows  evaporation  or  some  other  injmious  influence.  The  efficiency 
of  nutrition  is  manifested  by  the  decided  changes,  chemical  and  vital,  which 
are  seen  in  constant  operation  within  the  beings — such  as,  among  others, 
the  transformation  of  clilorophyll  into  starch,  and  of  one  or  both  these  into 
an  oily  matter. 

When  in  the  '  stiU  '  encysted  condition  (XIX.  4-1-69),  aU  nutritive  changes 
are  at  a  standstill,  and  the  organism  may  exist  ^Aeeks,  months,  and  even 
years  unchanged,  until  external  conditions  are  sui3plied  to  awaken  its  latent 
energies  and  to  renew  the  cycle  of  Hfe.  In  this  torpid  form  the  spores  are 
carried  about  with  the  dust,  or  remain  buried  in  the  earth,  or  are  elsewhere 
hidden  or  stored  up  against  the  day  of  revival. 

The  passage  into  the  '  stiU '  condition  by  the  throwing-out  of  an  external 
denser  envelope  and  by  the  loss  of  ciHa,  is  governed,  it  would  seem,  in  some 
measure  by  external  circumstances.  Motile  forms  are  replaced  by  the  ^  stiU ' 
in  whole  or  in  part,  and  with  greater  or  less  rapidity,  by  poimng  the  water 
containing  them  into  a  larger  and  shallower  vessel,  and  by  gradual  evaporation. 

The  protoplasm  of  Phytozoa  being  homologous  in  all  perceptible  particulars 
\\\th.  the  '■  sarcode '  of  Protozoa,  suffers,  like  it,  the  destructive  process  of 
'  diffluence '  or  '  deliquescence '  when  evaporation  reduces  the  quantity  of 
water  around  the  improtected  motile  forms  below  the  quantity  necessary  to 
\'ital  action.  The  first  noticeable  result  of  evaporation  is,  according  to  Cohn, 
at  least  in  the  instance  of  Protococcus  (op.  cit.  p.  538),  a  more  rapid  change 
of  figure  and  appearance,  followed,  if  the  evaporation  continue,  by  diffluence, 
in  which  he  distinguishes  two  stages  or  phases  :  — ''  In  the  fu'st,  the  outlines 
appear  less  sharply  defined,  because  the  coloured  substance  is  somewhat 
retracted  from  the  border  of  the  piimordial  cell ;  the  cells  become  flattened, 
and  at  the  same  time  ^^ider :  the  contents  are  also  now  altered  ;  previously 
more  homogeneous  and  transparent,  they  now  become  thi^oughout  granular, 
and  the  red  substance  runs  together  in  large  drops.  At  this  time  the  forma- 
tion of  vacuoles  commences ;  and  their  number  continues  to  increase.  In  this 
way  the  interior  of  the  primordial  cell  again  becomes  colourless,  clear  as 
water,  and  the  granular  coloui-ed  contents  pressed  against  the  walls.  .  .  .The 
figiu-e  of  the  cell  in  the  warm  time  is  so  much  expanded,  that  it  comes  to  be 
apphed  upon  the  wall  of  the  enveloping  cell,  alternately  filhng  it  altogether, 
so  that  the  entire  zoospore  appears  to  consist  of  only  a  single  coloiu'cd  gra- 
nular vesicular  disc,  corresponding  in  size  with  the  original  enveloping  cell." 

Multiplication  and  Reproduction  of  Phytozoa.  Fission  :  Macrogonidia  ; 
MicROGONiDiA  :  Encysting  process  :  Phases  of  existence. — The  multiplica- 
tion of  the  individuals  of  the  species  of  Phytozoa  is  provided  for  by  the 
process  of  self- division,  deduplication,  or  fission.  This  takes  place  according 
to  the  plan  obtaining  in  vegetable  and  animal  cells  in  general. 


OF  THE  PHYTOZOA.  121 

The  cell-contents  divide  into  two  or  more  segments,  each  of  which  can 
further  develope  around  itself  a  gelatinous  investment,  and  enter  on  an  inde- 
pendent existence.  In  Euglena,  self-division  occurs  longitudinally  into  two 
portions  ;  and  the  newly- developing  half  is  of  smaller  size  than  the  other,  but 
becomes  complete  in  all  its  parts  before  its  severance  is  effected. 

The  motile  cells  of  Cldamydococcus  undergo  fission  into  two  or  four  seg- 
ments (XIX.  23-26)  :  this  takes  place  in  the  protoplasmic  or  primordial  cell 
contained  within  the  hyaline  spherical  enveJope-ce]l ;  when  division  is  com- 
plete, the  latter  is  ruptured,  the  sections  escape  as  independent  beings,  each 
throws  out  around  itself  its  envelope- cell,  and  in  aU  points  goes  through  the 
same  cycle  of  development  as  the  parent-cell.  Many  Monads  also  divide 
into  two  beings,  whilst  others  separate  into  foiu\  In  the  above-cited  ex- 
amples the  fission  is  complete,  and  each  segment,  on  detaching  itself  from  the 
other,  becomes  an  independent,  free  being. 

But  this  same  act  of  fission  may  proceed  under  different  circumstances ; 
and  instead  of  a  single  organism,  a  colony  may  be  formed,  consisting  of 
several  individual  cells  united  together,  either  permanently  or  only  for  a 
time,  within  a  common  envelope.  These  aggregate  Phytozoa  are  especially 
represented  in  the  family  Volvocinece. 

In  this  second  mode  of  fission  the  process  is  repeated  a  greater  number  of 
times — for  instance,  some  3,  4,  or  5  times — the  result  being  a  higher  midtiple 
of  2,  the  product  of  the  first  act  of  scission. 

Each  repetition  of  the  process  of  fission,  from  the  commencement  until 
its  completion,  constitutes,  in  Xiigeli's  language,  a  transitional  generation, 
whilst  the  final  repetition  produces  the  permanent  generation.  For  example, 
in  Stephanos]jha;ra  two  segments  are  produced  by  the  act  of  fission,  which  re- 
present the  first  generation  (XIX.  45) ;  then  each  of  these  subdivides,  and  so 
developes  four  portions  (XIX.  40,  46) — the  second  generation ;  and,  lastly, 
each  of  the  foiu'  separates  into  two,  and  in  that  way  produces  eight  segments 
— the  third,  and  in  this  organism  the  final  or  permanent  generation  (XIX. 
41,  42,  bQ). 

Unlike  the  segments  resulting  from  a  single  act  of  division,  or,  as  may 
happen,  from  this  act  once  repeated,  each  newly-formed  i^rimordial  cell 
does  not  commonly  siUTound  itself  with  an  envelope  and  enter  on  an  isolated 
existence,  but  the  whole  eight  or  more  continue  to  live  within  a  common 
tunic,  which  presently  expands  by  endosmotic  action  and  acquires  a  more  or 
less  spherical  figure  (XIX.  bQ,  57, 58).  Simultaneously  with  this  expansion, 
the  previously  contiguous  particles  are  drawn  away  more  and  more  from 
each  other,  and  chsposed  within  the  common  envelope,  after  a  more  or  less 
regular  fashion,  characteristic  of  the  species  to  which  they  belong  (XIX.  42, 
58).  In  general,  the  separation  of  the  primordial  cells  is  not  complete; 
bonds  of  union  between  them  in  their  early  state,  when  closely  approximated, 
become  cbawn  out,  and  ultimately  present  themselves  as  interciuTcnt  thj-eads. 
When  this  series  of  changes  is  terminated,  we  have  before  us  a  reproduction 
of  the  aggregate  organism  of  which  the  dividing  primordial  cell  was  but  an 
individual  member.  Braiin  has  styled  this  variety  of  reproduction  by  fission, 
development  by  '  Diacrogonidia.^  It  is  well  illustrated  in  Steplianosphcera, 
above  cited,  in  Volvox  (XX.),  in  Goniiim  and  Pandorina  (XIX.  35,  36,  37, 
and  62-66),  and  also  in  undoubted  Algae,  the  Hydrodictyon  or  Water-net 
for  example. 

But  the  segmentation  of  the  cells  of  Phytozoa  occurs  in  yet  another  form ; 
i.e.  the  fission,  instead  of  stopping  at  the  third  or  foiuih  generation,  pro- 
ceeds still  further,  until  32  or  64,  a  hundi'ed,  a  thousand  and  upwards  of 
minute  cell- structures  are  produced,  technically  called  '  micror/onidia,'  in- 


122  GENERAL  HISTOEY  OF  THE  INFUSORIA. 

tended  to  perpetuate  the  species  by  their  ulterior  development.  Although, 
like  the  '  macrogonidia,'  they  are  formed  within  a  common  envelope,  yet 
each  cell  among  them  does  not,  as  in  those  products,  enclose  itself  with  its 
own  tunic,  and  fix  itself  permanently  within  the  general  investment — in 
other  words,  assume  at  once  the  '  still '  condition  ;  but  the  whole,  after  entire 
separation  from  one  another,  become  endued  with  vital  acti^dty,  and  are  sub- 
sequently set  free,  by  the  dissolution  or  ruptm^e  of  the  surrounding  parent-ceU, 
as  so  many  moving  zoospores  (XIX.  51).  The  motion  of  these  Httle  bodies 
"within  the  original  cell  is  of  a  hurrying  to-and-fro  or  up-and-down  cha- 
racter, and  has  been  styled  '  swarming.'  On  emerging  from  the  ruptui^ed 
ceU,  each  little  body  is  seen  to  have  a  spindle-shaped  figiu-e,  terminated  at  its 
anterior  clear  and  usually  elongated  extremity  by  two  or  fom-  cilia  (XIX.  52). 
In  eveiy  essential  particular  these  microgonidia  are  homologous  with  the 
motile  gonidia,  swarming- cells,  or  spores  of  the  common  Algae,  such  as  Bry- 
opsis,  Codium,  Achlya,  Chcetophora ,  VlothrLv,  Hydrodictyon,  &c.  Cohn's  re- 
marks on  the  formation  of  microgonidia  in  Stephanosphoira  {A.  N.  H.  1852,  x. 
p.  346)  may  elucidate  this  subject  stiU  fiu'ther.  He  says,  "  While,  in  the 
formation  of  macrogonidia,  the  secondary  cells  become  surroimded  by  a 
common  envelope  and  are  not  free  (as  an  entii-e  connected  family  of  ceUs 
arranged  according  to  a  definite  law),  in  the  mode  of  propagation  of  micro- 
gonidia the  little  secondary  ceUs  finally  become  totally  separated  from  one 
another  without  secreting  an  envelope-cell;  and  in  this  way  each  of  the 
eight  primordial  cells  of  the  perfect  Steplianosplicera  is  broken  up  into  32  to 
64  independent,  green,  elliptical  or  spindle-shaped  corpuscles,  which  then 
separate  from  one  another,  commence  an  independent  and  active  motion,  and 
fill  up,  in  great  numbers  (as  many  as  256-512),  the  common  parent  envelope- 
cell  (XIX.  51).  .  .  .  The  crowding-in  among  each  other  of  the  microgonidia  of 
Steplianosph<xra  presents  a  picture  fixing  the  attention  in  the  highest  degree : 
sometimes  the  cellules  are  scattered  in  a  few  large  masses — then  they  unite 
again  into  a  knot  in  the  middle — every  moment  the  general  aspect  varies. 
At  length  the  common  envelope  is  ruptured,"  and  they  escape  in  masses 
into  the  water.  *'  Their  true  form  may  then  be  detected  readily  by  killing 
them  with  iodine  ;  they  are  spindle-shaped  and  acuminated  at  both  ends, 
bright  green  in  the  middle,  and  run  out  into  a  colouiiess  beak  at  each  end — ■ 
on  the  whole  not  unlike  young  EugJence,  without  trace  of  an  envelope-cell 
(XIX.  Q2)y  On  reaching  the  water  their  movements  are  most  active,  and 
then  rapidly  disperse  out  of  sight.  These  bodies  are  true  primordial  cells, 
*'  that  is,  primordial  utricles  resembling  cells,  organized  exclusively  of  co- 
loured protoplasm,  mthout  any  cell-membrane." 

Upon  a  general  survey  of  development  by  gonidia,  Cohn  remarks  {A.  N. 
H.  1852,  X.  p.  403) — "  Abstracting  the  differences  which  may  always  be 
shown  between  two  genera,  we  detect  the  same  law  of  development  in  Hy- 
drodictyon as  in  Stephanosphcvra :  the  biciliated,  less  numerous  macrogo- 
nidia arrange  themselves  into  a  family  of  cells  abeady  within  the  parent-ceU, 
according  to  the  character  of  the  given  conditions  of  the  two  genera, — the 
cell-family  being  active  in  the  Volvociueae  and  immoveable  in  the  Proto- 
coccaceae ;  while  the  more  numerous,  more  actively-moving  microgonidia 
with  four  cilia  leave  the  parent- cell  and  enter  upon  a  metamorphosis,  the  re- 
trogradation  from  which  to  the  normal  type  of  the  genus  has  not  been  ob- 
served yet  here,  or  indeed  in  the  microgonidia  of  any  of  the  Alga3,"  It  may 
be  conjectui-ed  that  these  latter  pass  into  a  resting  state,  prior  to  any  further 
development ;  for  both  Cohn  and  Braun  have  witnessed  this  change  tu 
Chlamydococcus  pjluvicdis. 

The  formation  and  escape  of  microgonidia  have  been  observed  by  many 


OF  THE  PHTTOZOA.  123 

naturalists — for  instance,  by  Weisse  in  Cldorogonmm,  and  by  Perty  in  each 
family  of  Phytozoa.  The  production  of  such  bodies  is  frequently  treated  of 
as  development  by  germs,  and,  no  doubt,  is  the  same  phenomenon  Ehi^enberg 
represents  as  \dviparous  reproduction. 

Microgonidia  are  not  so  commonly  developed  as  macrogonidia ;  and  indeed 
their  formation  would  seem  determined,  at  times  at  least,  by  external  cir- 
cumstances affecting  their  functions  and  vital  activity  unfavom-ably.  Thus, 
Cohn  (Entiv.  p.  168)  narrates  the  circumstance  of  the  peculiar  and  pretty 
general  development  of  microgonidia,  in  Clilcnmjdococcus,  after  a  thunder- 
storm. 

Peocess  of  Encystln'g  :  Coxdition  of  rest. — The  perpetuation  of  Phytozoa 
is  provided  for,  as  before  intimated,  by  another  process,  which  both  secures 
to  the  cells  imdergoing  it  a  power  of  successfully  resisting  influences  that 
to  unprotected  gonidia  are  destructive,  and  is  connected  with  an  ulterior  act 
of  development.  This  faculty  of  self-protection  is  called  "  the  encysting  pro- 
cess," since  by  it  the  cell  encloses  itself  within  an  additional  fii-m  timic,  which 
suiTounds  it  like  a  case  or  cyst,  and  transforms  it  into  a  'still'  or  'whiter  '  spore. 

The  process  takes  place  in  all  the  Phytozoa  after  the  same  fashion :  the 
protoplasmic  covering  of  the  gonidium  or  cell  secretes  around  it  a  dense,  firm 
envelope,  which  in  general  becomes  raised  from  it  all  round,  so  as  to  leave  a 
clear  intervening  space.  On  the  assumption  of  this  extra  coveiing,  cells 
previously  motile  and  active  enter  on  the  '  still '  condition  and  lose  their 
ciha ;  at  the  same  time,  the  character  of  the  contents  is  altered,  and  a  red 
colour  frequently  acquii^ed.  The  transformation  in  their  physical  structm^e 
is  accompanied  by  a  physiological  change  ;  for  in  place  of  seeking  the  light, 
exhahng  oxygen,  and  carrying  on  all  the  vital  processes  with  a  corresponding 
activity,  they  sink  to  the  bottom  and  conceal  themselves  from  the  light.  It 
appears,  from  Cohn's  researches  on  Protococcus,  Gonium,  and  other  Phytozoa, 
that  they  become  released  from  their  imprisonment,  under  the  influence  of 
favourable  external  conditions,  by  the  dehquescence  of  the  rigid  external  sac, 
and  sometimes  by  its  transfonnation  into  an  external  mucilaginous  invest- 
ment, and  by  the  breaking-up  of  the  internal  protoplasmic  cell  into  a  number 
of  motile  zoospores. 

The  act  of  encysting  may  proceed  with  macrogonidia  in  their  '  still '  con- 
dition ;  or  it  may  overtake  motile  primordial  cells,  as  in  the  case  of  EugJena 
and  of  some  phases  of  Protococcus,  and  in  such,  just  as  in  the  zoospores  of 
Algae,  prove  antecedent  to  further  acts  of  development  by  fission.  Cohn  im- 
plies, in  his  history  of  Protococcus,  that  microgonidia  may  themselves  be  en- 
cysted ;  and  the  same  eminent  observer  describes  the  primordial  cells  of  that 
plant  as  in  some  instances  suiToimding  themselves  with  a  fii'm  external 
envelope,  pushing  out  two  cilia,  and  moving  about  for  a  time  in  a  'swarming' 
manner  ere  assuming  the  '  still '  condition,  when  the  cilia  disappear.  But, 
fiu'ther,  he  shows  that  gonidia,  furnished  with  a  rigid  external  waU,  proceed 
to  develope  others  like  themselves  by  self-division  of  their  substance  (XIX. 
25),  and  that  these  secondary  cells,  each  included  within  its  own  sac,  go  on 
to  divide  into  other  spores,  which,  however,  prove  not  to  be  '  still '  like  their 
parents,  nor  hke  them  encysted,  but  motile  zoospores. 

In  the  aggregated  family  Yolvocinese,  some  or  all  the  primordial  cells  be- 
come encysted.  When  this  takes  place,  their  contents  grow  thicker,  less 
transparent,  darker,  and  change  from  green  to  bro^\Ti  and  brownish,  or  to 
a  yelloA\ish  red.  At  the  same  time,  the  interciUTent  filaments  disappear,  the 
cells  themselves  acquire  a  more  s]3herical  figm^e,  and  gradually  loosen  them- 
selves from  the  common  envelope,  and  move  slowly  about  ^vithin  it  by  means 
of  two  ciha,  until  they  at  length  escape  by  a  rupture  at  some  point  (XIX.  44, 


124  GENEEAL  HISTOEY  OF  THE  nfEUSOEIA. 

50),  These  encysted  spores  resemble  Chlamydomonads,  and  are  called  *  Pro- 
toccocoid '  cells  or  globules,  from  thek  homology  -^ith  the  encysted  cells  of 
Protococcus. 

Occasionally,  instead  of  one  or  several  of  the  individual  gonidia  of  a  com- 
pound organism  being  encysted,  the  process  ensues  with  a  gonidium  deve- 
loped by  fission  into  macrogonidia,  and  the  whole  mulberry  or  Uvtlla-^e 
mass  becomes  surrounded  by  a  rigid  envelope,  either  pretty  closely  applied, 
or  separated  by  an  interspace. 

Examples  of  the  encysted  condition  ^\ill  occur  in  the  followdng  account  of 
the  several  groups  of  Phytozoa ;  it  sufiices  at  present  to  say  that  Prof.  Wil- 
liamson and  others  have  pretty  clearly  shown  that  VoJvox  aureus  is  only  the 
encysted  or  '  still '  form  of  V.  yJohator,  that  Cohn  has  discovered  the  cysts  of 
StejihanosjjJicera,  Gonium,  and  Eudonna,  and  Henfrey  those  of  Pandorina. 

The  after-history  of  the  encysted  spores  of  Phytozoa  has  not  yet  been 
elucidated :  we  have  above  referred  to  Cohn's  researches  upon  it ;  but  they 
are  too  indefinite  to  supply  any  positive  information.  The  act  of  conjugation 
is  common  with  many  of  the  lower  Algae,  but  has  not  been  witnessed  among 
the  Phytozoa. 

Phases  of  Beixg  axd  Alternation  of  Geneeation  in  Phytozoa. — From 
the  preceding  accoimt  of  Phytozoa,  it  is  evident  that  those  best  known  exist 
under  a  considerable  variety  of  form — in  other  words,  present  several  phases 
of  existence,  or,  viewed  in  relation  -svith  a  prevailing  hypothesis,  exhibit 
an  alternation  of  generation.  The  whole  history  of  any  Phytozoon  is  com- 
prehended m  the  cycle  of  changes  which  the  organism  passes  through ;  yet, 
under  any  transformation,  it  is  the  self- same  being,  and  its  existence  may 
be  said  to  extend  from  its  most  perfect  through  all  intermediate  phases  imtil 
the  like  degree  of  perfection  is  again  attained.  As  happens  in  alternation 
of  generations  among  other  organized  beings,  the  transition  may  not  be 
direct  and  simjDle,  but  intermediate  phases  may  reproduce  themselves,  and 
these  again  develope  into  other  forms  of  existence,  as  accessory  or  collateral 
and  usually  imperfect  cycles. 

Perhaps  the  metamorphoses  in  question  are  most  striking  in  Euc/Ience ;  for 
the  contrast  between  the  actively- mo^T^ng,  contractile,  ever- changing  being 
in  one  phase  of  existence,  and  the  encysted,  '  Protococcoid,'  spore-like  and 
motionless  condition  mth  a  rigid  unvarying  outline,  is  so  remarkable  as  to 
give  colour  to  the  hypothesis  of  the  convertibiHty  of  animal  into  vegetable 
life,  or  of  the  transformation  of  animals  into  plants.  It  is  not  our  intention 
at  present  to  give  illustrations  of  the  vailing  phases  in  the  life  of  Phytozoa 
involved  in  the  process  of  fission,  or  of  a  duplicative  multipHcation  under  its 
various  forms.  However,  other  more  extended  instances  of  transformation 
require  to  be  noted,  as  observed  by  various  microscopists, — although,  it  may 
be,  some  errors  have  crept  in,  from  the  difiiculty  of  tracing  the  relation  and 
succession  of  the  different  phases  of  being. 

As  a  veiy  good  example  of  the  wide  and  varied  range  of  existence  enjoyed 
by  most  Phytozoa,  we  may  adduce  the  Protococcus  pluvialis  (XIX.  20-31), 
of  which  the  industry  and  perseverance  of  Prof.  Cohn  have  obtained  for  us 
so  complete  an  account.  According  to  the  researches  of  this  eminent  natu- 
ralist, the  simj)le  plant  in  question,  in  its  motile  and  still  conditions,  assumes 
the  form  and  characters  of  many  microscopic  organisms  presumed  to  be,  and 
described  by  Ehrenberg  and  others  as,  distinct  existences.  To  quote  from 
Cohn's  memoir  {R.  S.  p.  559),  "  We  see  that  a  single  species,  omng  to  its 
numerous  modes  of  propagation,  can  pass  thi'ough  a  number  of  very  various 
forms  of  development,  which  have  been  either  erroneously  arranged  as  distinct 
genera,  or,  at  least,  as  remaining  stationary  in  those  genera,  although,  in 


OF  THE  PnTTOZOA.  125 

fact,  only  transitional  stages.  Tims,  the  '  still '  Protococcus-dQW.  coiTesponds 
to  the  common  Protococcus  coccoma  (Kiitz.).  "WTien  the  border  becomes  gela- 
tinous, it  resembles  P.  pulclier,  and  the  small  cells  P.  minor.  The  encysted 
motile  zoospore  is  the  genus  Oyges  gi^anulum  among  the  Infusoria,  resembling 
also,  on  the  other  side,  P.  tnrgidus  (Kiitz.),  and  perhaps  P.  versatilis  (Braun). 
The  zoospores  divided  into  two  must  be  regarded  as  a  fomi  of  Gi/ges  hipar- 
titus,  or  of  P.  dimidiatus.  In  the  quadripartite  zoospores,  with  the  secondary 
cells  arranged  in  one  plane,  we  have  a  Gonium.  That  with  eight  segments 
corresponds  to  Pandorina  Moriim,  and  that  with  sixteen  to  Botryocystis 
Volvox.  A\Tien  the  zoospore  is  divided  into  thirty-two  segments,  it  is  a  Uvella 
or  Syncrypta.  ^Tien  this  form  enters  into  the  '  still '  stage,  it  may  be  re- 
garded as  a  form  analogous  to  Microhcdoa  protogenita  :  this  Algal  genus  is 
probably,  speaking  generally,  only  the  product  of  the  Z7i'€7?«- division  in  the 
Euglence  or  other  green  forms.  The  naked  zoospores,  finally,  would  represent 
the  form  of  a  Monad,  or  of  an  Astasia  ;  the  caudate  variety  approaches  that 
of  Bodo.  A  critical  and  comparative  consideration  of  the  foregoing  facts 
would  therefore  appear  to  render  untenable  almost  all  the .  principles  which 
modern  systematists  have  hitherto  adopted  as  the  basis  for  construction  of 
their  natui-al  kingdoms,  families,  genera,  and  species." 

Cohn  {op.  cit.  pp.  541,  542)  makes  the  following  general  deductions : — 
"  1.  The  Protococcus  pluvialis  is  a  plant,  subject  to  an  alternation  of  genera- 
tions ;  that  is  to  say,  the  complete  idea  of  the  species  is  not  exhibited  in  it 
until  after  a  series  of  generations.  The  forms  of  development  which  can  be 
possibly  comprehended  in  the  idea  of  the  species  do  not  in  reality  make 
themselves  apparent  until  a  series  of  independent  successive  generations  has 
been  gone  thi^ough.  2.  The  individuals  of  each  generation  are  capable  of 
propagating  themselves  in  new  generations.  The  individuals  of  the  second 
generation  are  among  themselves,  speaking  generally,  of  equal  value  :  as  re- 
spects the  individuals  of  the  parent  generation,  they  are  sometimes  of  equal 
value  with  them,  sometimes  not.  3.  If  the  secondary  cells  are  not  of  equal 
value  with  the  parent-cells,  a  series  of  successive  generations  mu,st  precede 
the  last  generation,  the  individuals  of  which  are  again  equivalent  to  the  first 
mother- cell.  The  number  of  these  generations  does  not  seem  to  be  deter- 
minate." By  equivalent,  the  author  means  such  individuals  or  generations 
as  correspond  with  each  other  in  their  essential,  physiological,  and  organo- 
logical  relations,  although  they  may  differ  in  unessential  properties,  such  as 
colour,  size,  internal  consistence,  &c.  Xon- equivalent  are  those  generations 
which  in  theii'  stnicture  and  vital  relations  exhibit  essential  differences,  such 
as  '  still '  and  '  motile '  cells,  and  among  these,  again,  their  various  forms, 
and  particularly  those  which  are  derived  from  a  different  mode  of  propa- 
gation. 

Major  von  Flotow  {Nova  Acta  Acad.  Nat.  Curios.  1844,  p.  413),  it  is 
right  to  state,  remarked  on  the  similarity  of  various  forms  of  development 
of  Hcematococcus  {Protococcus,  Cohn)  pluvialis  with  Infusoria,  signahzing  the 
genera  Chiloraomis,  Cryptomonas,  Gyges,  Chlamydoiyionas,  Pandorina,  Clice- 
toglena,  and  Chcatotyphla  of  Ehrenberg's  system. 

Phytozoa,  or  structiuTS  undistinguishable  from  them,  constitute  links  in 
the  chain  of  still  more  marvellous  transformations.  Thus,  Itzigsohn  repre- 
sents several  in  the  history  of  the  development  of  the  Oscillatorieoe.  For  ex- 
ample {J.  M.  S.  1854,  p.  189) — "  The  filaments  of  OsciUaforia  tenuis  break  up 
into  perfectly  distinct  joints,  which,  at  first  urceolate,  soon  become  spherical. 
The  minute  yellowish -green  gonidia  thus  arising  gradually  increase  in  size, 
become  motile,  and  present  in  aU  respects  the  aspect  of  Cldamydomonas.'" 
These  bodies  "  gradually  enlarge  ;  a  red  eye-point  becomes  visible  in  them  ; 


126  GENERAL  HISTOEY  OF  THE  INFUSORIA. 

and,  presenting  a  thousand  intermediate  forms,  they  grow  iato  perfect 
Euglencey  After  awhile  these  Euglence  become  encysted,  and  terminate  in 
the  quiescent  or  '  Profococcws-condition,'  and  subsequently,  by  self-division 
of  the  contents,  are  resolved  into  motile  microgonidia  which  escape  free  into 
the  water.  "  If  a  number  of  these  remain  conjoined,  and  move  about  with  a 
rowing  kind  of  movement,  their  locomotion  being  governed  by  a  common 
spontaneity,  they  represent  a  VoIvoxAj^q  colony,  which,  perhaps,  may  even 
have  been  described  as  VoJvox  by  authors.  The  microgonidia  of  the  Eughna, 
like  those  of  all  the  Algae  hitherto  examined  by  me,  are  the  motile  parent- 
cells  of  extraordinarily  minute  spiral  filaments.  They  are  at  first  green, 
gradually  becoming  pellucid — exactly  hke  the  spermatospheres  of  Spirogyra^ 
presenting  a  Monadifonn  aspect.  A  pecuhar  appearance  arises  when  many 
microgonidia  in  such  groups  remain  green  wliilst  the  others  have  already 
become  clear  as  water ;  the  mass  then  presents,  in  fact,  the  aspect  of  being 
composed  of  two  kinds  of  animalcules.  Such  or  similar  conditions  would  re- 
present several  species  of  the  supposed  genus  UvelJa  (atomus,  glaucoma,  Bodo, 
&c.).  Each  ultimately  colomiess  microgonidium,  then,  by  the  dissolution  of 
its  minute  gelatinous  envelope,  discharges  a  small  motile  spu^al  filament."  .  .  . 
''  These  spiral  filaments  do  not  appear  to  be  destined  for  the  purposes  of  im- 
pregnation ;  for  they  gradually  increase  in  length  and  thickness,  soon  exhi- 
bitiag  numerous  spiral  tiu'us,"  and  then  exchange  the  Sinrilla-Yike  for  a 
Sj)iruJ uia-f orm.  "■  Finally,  when  their  motile  faculty  has  become  weakened, 
they  afiix  themselves  by  one  extremity  to  any  larger  object  near  (for  instance, 
Conferva-filaments,  &c.),  whilst  the  other  extremity  continues  to  move  about 
with  a  creeping  motion — the  peculiar  Oscillatorian  movement,  in  performing 
which  a  young  filament  frequently  returns  to  the  spiral.  The  last-described 
condition  constitutes  the  Leptothrix  of  authors.  The  filaments  now  graduallj' 
become  thicker  ;  and  though  at  first  of  the  hghtest  emerald-green,  they  gra- 
dually assume  a  deeper  and  deeper  tint.  The  fii'st  indications  of  articulation 
are  perceptible  in  them,  until  at  last  a  young  OsciUatoria  is  again  perfected." 
But  the  remarkable  metamoq^hoses  of  this  OsciUatoria  are  surpassed 
by  those  of  the  Phytozoa  of  antheridia,  as  recounted  by  Prof.  Hartig 
(J.  M.  S.  1855,  p.  51)  :  the  antheridia  of  Marcliantia  form  the  subject  of 
observation.  Theii'  Phytozoa  fii'st  assume  the  foim  of  Ehrenberg's  genera 
Spirillum  and  Vibrio,  of  which  the  most  frequent  varieties  met  with  are 
Vibrio  rugula  and  V.  prolifera ;  '^  after  twenty-fom'  hours  most  of  these 
Vibrios  and  Spirilla — after  forty-eight,  all  of  them — have  become  disarticu- 
lated." The  whole  di'op  of  water  in  which  they  float  is  now  rendered 
milky  and  turbid  by  numberless  globules,  similar  to  Monas  crepusculum,  in  a 
state  of  active  motion ;  and  it  is  an  important  circumstance  that  Spirillum 
does  not  originate  from  Monas,  but  always  Monas  from  Spirillum.  After 
forty-eight  hours,  "^  groups  of  several  hundi-eds  may  frequently  be  seen,  in 
which  the  primaiy  active  motion  has  ceased.  Shortly  aftei-wards  a  sharply- 
defined  hyaline  skin  is  formed  round  these  groups,  and,  as  it  would  seem, 
by  the  amalgamation  or  conjunction  of  the  exterior  molecules  ;  by  this 
means  the  young  Amceba  (Proteus)  is  formed.  Tliis  transformation  takes 
place  pretty  regularly  towards  the  end  of  the  thii'd  day.  The  original  size 
of  the  Amceba  is  1-300'"  in  diameter.  In  the  course  of  three  or  four  days, 
it  grows  to  about  the  size  of  1-100'".  This  species  diff'ers  from  the  Amoebce 
hitherto  described,  in  the  fact  that  the  inner  portion  of  the  body  which  bears 
the  granules  is  much  smaller  than  a  certain  hyaline  coveiing,  which  covering 
is  closely  attached  to  the  hinder  part  of  such  inner  portion,  but  extends  far 
away  from  the  anterior  part ;  and,  in  addition  to  this,  the  progressive  motion 
in  this  species  originates  in  an  alternate  enlargement  of  the  longitudinal  and 


OF  THE  PHYTOZOA.  127 

transverse  diameters,  and  is  so  slow  as  to  amount  at  the  utmost  to  no  more 
than  1-40'"  per  minute.  The  form  of  the  body  resembles  that  of  Amoeba 
princeiis  (Ehrenberg).  The  vesicle  in  the  hinder  part  of  the  body,  which 
was  fii'st  described  by  Ehrenberg  as  a  mouth,  and  afterwards  as  an  ovarium, 
is  also  present. 

"^  After  four  or  five  days  the  Amoeba  assumes  a  spherical  shape  and  becomes 
motionless,  the  vesicular  body  expanding  and  contracting  rapidly  as  before, 
in  a  manner  similar  to  what  takes  place  in  many  Vorticellce.  These  spherical 
motionless  Amoebce  are  then  for  the  most  part  united  by  a  mucilage  into 
groups  of  from  ten  to  twenty.  The  mucilage  appears  to  be  produced  by  the 
decomposition  of  a  cast-off  external  skin. 

"  In  about  a  fortnight  after  the  commencement  of  the  experiment,  a  green 
point  appears  in  the  interior  of  the  spherical  colourless  body  of  the  Amoeba  ; 
this  point  gradually  increases  in  size  until  it  fills  up  the  entu-e  hollow  of  the 
Amoeba,  and  after  becoming  covered  with  a  cuticle  it  escapes  in  the  form  of 
an  elliptical  bright  green  cell,  1-300'"  in  diameter,  resembhng  a  Protococcus. 
It  exhibits  a  round  transparent  cavity,  devoid  of  chlorophyll,  corresponding 
in  size  and  position  to  the  vesicular  body  of  the  Amoeba,  and  resembling  at 
its  coloiu'less  apex  the  motile  gonidia  of  Cladajjliora.  A  few  days  later  the 
elliptic  or  roundish  cell  lengthens,  a  fonnation  of  transverse  septa  commences, 
and  the  unicellular  Alga  becomes  an  articulated  one. 

"  All  these  transformations  of  Phytozoa  into  SpirUla,  Vibriones,  Monads, 
Amoebce,  unicellular  and  articulated  Algse,  may  be  observed  not  only  in  the 
detached  Phytozoa,  but  in  those  wliich  remain  in  the  interior  of  the  sections 
of  the  antheridia.  In  those  antheridia  of  which  the  Phytozoa  are  not  fully 
ripe,  the  Amoebce  are  seen  to  originate  in  the  middle  of  the  internal  mass  of 
phytozoary  cells :  some  of  them  make  their  way  out  through  the  softened 
mass  of  cellular  tissue ;  but  others  remain  in  the  interior  of  the  antheridium 
until  their  development  into  an  articulated  Alga. 

"  Contemporaneously  with  Amoeba,  and  often  earlier,  there  may  be  seen, 
amidst  the  mass  of  Monads,  bodies  very  similar  in  form  and  motion  to  the 
genus  Boclo  (socicdis),  and  which  increase  by  transverse  division ;  they  have 
the  front  end  fm-nished  with  a  long  whip-shaped  antenna  or  cihum  similar 
to  that  of  Euglena.  At  their  fii^st  appearance,  their  motion,  their  change  of 
form,  and  their  whole  exterior  differ  so  Kttle  from  the  earhest  states  of 
Amoeba,  that  at  this  period  they  cannot  be  distinguished.  In  these  early 
stages  they  both  resemble  CJdamydomonas  destruens  of  Ehrenberg. 

"  The  above  forms  imiformly  make  their  appearance,  and  always  in  the 
succession  above  described.  It  is  true  that  other  forms,  such  as  Uvellce  and 
even  Lejotomitce  and  Periconice,  are  sometimes  met  with,  the  germs  of  which 
may  have  been  imported  by  the  atmosphere  dming  the  observation ;  but  these 
organisms,  ivliich  cdivaijs  appear  singly  and  after  the  commencement  of  the 
observation,  do  not  interfere  with  the  above  results  when  we  consider  the 
immense  number  of  the  Phytozoa  and  their  uniform  and  contemporaneous 
transformations.  If  about  a  dozen  preparations  are  made,  and  if  they  are 
carefully  covered  with  a  bell-glass  after  each  observation,  and  if  care  be 
taken  not  to  extend  the  observations  for  too  long  a  time  at  once,  at  least  half 
of  the  preparations  -will  be  free  from  all  admixture  of  foreign  organisms." 

Itr.  Carter  has  advanced  some  remarkable  statements  respecting  the  de- 
velopment of  Amoebifonn  and  other  Infusoria  from  the  so-called  '  gonidial 
ceUs '  of  the  mucous  contents  of  various  Algae — as  Chara,  NiteUa,  Clado- 
phora,  Spirogyra,  and  Hydrodictyon,  and  also  of  some  Desmidieae  and  Eu- 
glenece  (A.  N.  H.  1856,  xvii.  p.  101).  Again,  he  finds  (p.  114)  the  cells  of 
Spirogyroi  particularly  infested,  during  conjugation,  with  EugJence,  which  are 


128  GEXEEAL  HISTOEY  OF  THE  I^FUSOEIA. 

produced  with  such  rapidity  as  would  lead  to  the  conclusion  that  the  germs 
from  which  they  originate  must  have  pre-existed  in  the  cells  in  which  they 
appear  (as  in  the  Characece),  without  interfering  Avith  their  functions.  "  Young 
Astasice  are  also  developed  within  the  cells  of  Sjpirogyra  to  a  great  extent ; 
and  although  they  at  first  have  almost  as  much  polymorj^hism  as  an  Amoeba, 
still  they  retain  their  cihum,  and  after  awhile  assume  the  form  and  move- 
ments peculiar  to  Astasia.  On  one  occasion  I  saw  a  large  Amoeba  with  a 
long  cilium  at  one  time  assuming  the  form  of  an  Astasia,  and  at  another 
that  of  an  A7noeba,  which  thus  gives  the  link  between  these  two  Infusoria. 
The  cihum,  however,  had  not  the  power  of  the  filament  of  Astasia,  though  it 
occasionally  became  terminal." 

Developments  of  a  similar  Ehizopodous  character  are,  he  goes  on  to  say, 
frequent  in  Eurjlena  : — "  I  was  led  to  notice  this  development  by  an  apparent 
metamorphosis  of  the  cell- contents  of  some  fixed  and  capsuled  EacjJence  into 
granuliferous  Amoebce,  of  a  pinldsh  colom%  within  the  old  cell  of  Euylena 
itself ;  and  the  presence  of  several  such  Amoebce  creeping  about  the  watch- 
glass,  while  many  of  the  cells  of  the  EwjJence  (viridis'?)  were  empty,  or  only 
contained  a  little  effete  matter,  left  no  doubt  in  my  mind  as  to  the  origin  of 
both  coloiu'  and  infusorium.  It  was  also  observed  in  some  instances,  where 
the  contents  of  the  Euglena  had  passed  into  an  Amoebous  mass,  that  the 
latter  imderwent  a  kind  of  segmentation,  so  that  several  (perhaps  eight) 
small  Amoebce  were  developed  instead  of  one  large  one." 

Of  the  nature  of  Phttozoa.  Animal  and  Vegetable  Chaeactees. — 
The  collection  of  organisms  we  have  grouped  together  for  convenience'  sake, 
and  from  want  of  a  better  arrangement,  under  the  name  of  Phytozoa,  is 
actually  so  heterogeneous  that  no  general  discussion  respecting  the  natm-e  of 
them  as  a  class  is  practicable,  whilst,  at  the  same  time,  a  separation  between 
vegetable  and  animal  forms  is  equally  impracticable.  The  remarkable  phases 
of  existence  through  which  any  one  species  may  pass  upsets  all  our  notions 
based  on  presumed  constant  characters  :  for,  as  we  have  seen,  one  and  the 
same  being  may  at  one  period  of  its  existence  exhibit  in  a  preponderating 
degree  the  vital  phenomena  of  an  animal,  at  another  those  of  a  plant, 
whence  has  arisen  the  h5T^)othesis  of  the  metamoq^hosis  of  plants  into 
animals,  and  vice  versa, — an  idea  that  has  foimd  little  favoui%  being  opposed 
to  the  prevaihng  belief  of  the  fixity  of  nature  imposed  on  all  beings.  The 
real  fact  of  the  case  is,  that  we  have  no  certain  criterion  between  the  two  divi- 
sions of  organic  natiu^e  which  can  be  relied  on  and  practically  resorted  to  in 
cases  of  difiiculty,  such  as  many  of  the  Phytozoa  present. 

Some  natiu'alists  have  broached  the  notion  that  the  phases  of  existence  of 
a  presumed  animal  or  plant,  which  resemble  in  outward  aspect  supposed 
independent  species  or  genera,  are  not  identical  with  them  ;  so  that,  for 
instance,  the  animal-looking  Amoeba  Hartig  met  with  in  the  developmental 
series  of  Phytozoa  of  antheridia  should  not  be  considered  really  an  animal 
Amoeha,  but  merely  a  vegetable  mass  simulating  one.  So,  again,  in  Proto- 
coccv.s  they  would  deny  anything  but  external  gene^-al  characters  to  exist  in 
common  between  its  forms  of  development  and  the  several  genera  Cohn  would 
assimilate  them  with.  There  may  be  some  truth  in  this  supposition — there 
may  be  real  animal  organisms  and  true  vegetable  coinciding  in  form,  yet 
distinct  in  natiu'e  ;  but  the  onus  lyrobancU  rests  with  those  who  will  make 
this  distinction. 

However  this  may  be,  the  advance  of  science  has  rendered  it  certain  that 
some  families  and  genera  which  Ehrenberg,  and  most  obseiwers  before  his  era, 
reckoned  among  animals,  are  rightly  to  be  numbered  among  plants,  whilst 
of  others,  again,  it  must  still  be  said  their  position  is  doubtful.     Deferring 


OF  THE  PHYTOZOA.  129 

at  present  a  detailed  review,  we  will  confiue  ourselves  to  a  few  general  obser- 
vations on  the  nature  of  the  several  families  brought  together  under  the  head 
of  Phytozoa.  The  Monadina  (XYIII.)  of  Ehrenberg  comprise  a  multitude  of 
beings  differing  widely  among  themselves,  and,  for  the  most  part,  not  placeable 
with  certainty  either  among  plants  or  animals.  Of  the  genus  Monas,  especially, 
it  may  be  said  that  its  species  are,  with  few  or  no  exceptions,  mere  phases  of 
being  of  other  organisms.  Of  other  genera  the  like  may  be  presumed,  although 
the  organisms  in  whose  cycle  of  life  they  enter  as  one  of  the  links  have  not 
been  determined.  Not  a  few  are  doubtless  zoospores  of  Algae  or  of  micro- 
scopical Fimgi. 

Uvella  (XVIII.  5)  is,  in  the  opinion  of  most  authorities,  a  vegetable  struc- 
ture (see  p.  134)  ;  but  Cohn  (Entw.  p.  115)  still  seems  disposed  to  consider  it 
an  animalcule,  and  represents  Anthophysa  (see  p.  135),  which  has  likewise 
been  extensively  believed  to  be  a  parasitic  Alga  or  Fungus,  to  be  an  animal 
Uvella  sm^mounting  a  branching  stem.  Polytoma  is  another  disputed  posses- 
sion between  zoologists  and  botanists  :  among  the  most  recent  advocates  of  its 
animal  character  is  Schneider  (see  pp.  136-139). 

The  Cryptomonadina  would,  in  the  language  of  naturalists  generally,  be 
called  '  encysted '  Monadina,  and,  like  this  family,  are  divisible  into  true 
vegetable  and  into  doubtful  animal  organisms,  the  former  certainly  prepon- 
derating. The  next  two  families,  Volvocina  and  Vihrionia,  and  more  especially 
the  former,  may  without  hesitation  be  counted  with  plants,  whilst  the  remain- 
ing one,  Asfasicea,  the  majority  of  naturalists  reckon  among  animalcules. 

Habitats.  OccmEENCE  in  masses.  Colour  caused  by  theie  accumula- 
tion.— By  far  the  majority  of  known  Phytozoa  are  of  a  freshwater  habit ; 
yet  it  may  be  that,  were  the  search  as  diligent,  marine  species  might  be 
found  in  nearly  equal  abundance,  particularly  in  inland  and  shallow  seas, 
gulfs,  or  lakes  affording  appropriate  habitats  for  the  larger  Algae.  Monads 
and  Vibrios,  Bodos,  and  the  Cyclidia  of  Dujardin,  are  probably  the  most 
abundant  and  widely  diffused  of  all  created  organisms, — a  fact  not  remark- 
able when  it  is  considered  that  those  genera  represent  the  primary  or  ger- 
minal stage  of  so  many  organized  beings,  both  animals  and  plants.  They 
make  their  appearance,  in  collections  of  water  and  in  infusions,  before  all 
others,  and,  unlike  most  microscopical  creatures,  find  a  fitting  habitat  in  foul 
or  decomposing  fluids  as  well  as  in  sweet  water.  They  also  propagate  them- 
selves with  such  astonishing  rapidity,  that  the  fluid  or  other  medium  in 
which  they  occur  becomes  coloured  by  them.  However,  this  very  rapid  de- 
velopment, and  this  capability  of  colouring  the  siuTOunding  medium,  are  not 
restricted  to  the  genera  named,  but  are  partaken  by  others  among  the  Phy- 
tozoa,— for  example,  Uvella,  Astasia,  Euglena,  and  the  genera  of  Volvocinece, 
aU  of  them  denizens  of  pure  water,  incapable  of  existence  in  impiu'e,  stagnant, 
and  decomposing  liquids. 

The  coloiu'  presented  by  their  accumulation  in  large  numbers,  varies 
according  to  the  species.  Thus,  the  Astasia  hcematodes  and  Euglena  san- 
guinea  give  a  blood-red  colour  to  water.  The  Monas  (Vibrio) prodigiosa  is 
stated  by  Ehrenberg  to  be  the  cause  of  the  blood-hke  spots  which  have  made 
their  appearance  at  times  in  bread  and  meal,  much  to  the  consternation  and 
dismay  of  the  ignorant  and  superstitious ;  and,  again,  the  Hcematococcus  or  the 
red-coloured  stage  of  the  Hysginum  of  Perty  is  the  cause  of  the  phenomenon 
of  red  snow.  A  green  colour  is  much  more  frequent,  and  due  to  a  larger 
variety  of  Infusorial  organisms ;  such  are  Moyias  bicolor,  Uvella  Bodo,  Cryp- 
tomonas  glauca,  Gonium,  Chlorogonium,  Eiiglena  viridis,  Chlamydomonas, 
Pandorina,  Volvox,  Stephanosphcera,  and  others. 

Besides  becoming  thus  obvious  to  common  observation  by  their  colour. 


130  GENERAL  HISTORY  OF  THE  INFUSORIA, 

many  Phytozoa  render  themselves  so  by  the  evident  masses  or  accumulations 
they  form.  The  dust-hke  stratum  frequently  noticeable  on  the  surface  of 
water,  or  at  the  sheltered  margins  of  ponds,  is  often  composed  of  various 
genera,  such  as  Euglena,  ChJorogonium,  Pandoirina,  and  Gonium,  more  or 
less  intermingled  with  other  Infusorial  beings,  such  as  ciliated  Protozoa, 
Desmidieae,  and  Diatomese.  The  stratum  at  times  assumes  the  appearance 
of  a  slimy  film,  at  others  of  a  frothy  scum. 

Moreover,  the  variable  affinity  of  different  genera  for  light  will  cause  a  film 
at  one  part  of  a  pond  to  differ  in  its  composition  from  that  at  another,  when 
the  degree  of  exposure  of  the  two  is  different.  Eurther,  there  may  be  a 
transition  of  colour,  by  the  changing  phase  and  attendant  change  of  hue  of 
these  organisms,  or  by  the  effects  of  the  sun's  heat  and  hght  at  noonday, 
and  of  the  darkness  of  night.  Hence  a  pond  which  may  be  coloured  green  in 
the  warmth  of  the  day,  when  the  sun's  influence  brings  the  Phytozoa  to  the 
surface  and  causes  their  rapid  development,  may  in  the  morning  and  evening 
become  quite  clear,  o^^dng  to  their  settlement  at  the  bottom. 

Of  the  modes  of  obtaining  the  Phytozoa  for  examination  there  is  nothing- 
special  to  record,  except  it  be  a  plan  mentioned  by  Cohn  in  his  account  of 
Stephanosjihcera  {A.  N.  H.  1852,  x.  p.  405)  : — "At  their  stations,"  writes  this 
observer,  "  the  Step'hanospli(xra-^)\\.eYe^  occur  mingled  with  Chlamydococcus, 
but  by  no  means  in  the  abundance  requisite  for  the  investigation  ;  and  although 
green  clouds  do  collect  at  certain  points  in  the  water  wholly  composed  of  our 
VolvocinecB,  it  is  difficult  to  extract  sufficient  of  them  for  examination,  since 
they  immediately  start  apart  when  touched.  I  succeeded  in  overcoming  this 
inconvenience  by  a  simple  means,  so  as  to  bring  thousands  of  these  elegant 
organisms  on  to  the  object-holder  at  any  moment.  I  took,  namely,  a  flat 
bottle  with  a  short  narrow  neck,  and  nearly  fUled  it  with  the  water  contain- 
ing Stephanosph<x.r(B,  stopped  it  with  a  cork,  and  then  laid  it  horizontally,  so 
that  the  cork  partly  dipped  in  the  water.  In  a  few  hours  almost  all  the 
StepTianosphcerce  in  the  water  collected  on  the  cork,  which  was  covered  with 
a  green  coat,  composed  exclusively  of  the  revolving  spheres,  while  the  rest  of 
the  water  in  the  bottle  contained  only  Chlamydococcus,  and  scarcely  any 
Steplianosphcera ;  so  that  when  I  wished  to  examine  them  I  had  only  to  take 
out  the  cork,  and  a  drop  of  the  water  adhering  to  it  furnished  me  with  aU  the 
stages  of  development  of  our  organism  simultaneously  in  very  large  numbers. 
After  a  short  time  the  StephanospJicerce  had  again  assembled  on  the  cork." 

For  a  more  satisfactory  elucidation  of  the  Phytozoa,  of  their  structure  and 
physiological  action,  it  is  necessary  to  enter  into  more  detail ;  and  since  there 
is  so  much  structural  diversity  among  the  several  groups  or  tribes,  this  more 
lengthened  account  must  be  given  of  each  tribe  separately.     And  first — 


FAMILY  I.— OF  THE  MONADINA. 

(Plate  XYIII.  1-28.) 

In  the  systematic  portion  of  his  great  work,  in  1838,  Ehrenberg  instituted 
the  follo^ving  genera  of  Monadina,  viz.  Monas,  Uvella,  Polytoma,  Microglena, 
Phacelomonas,  Glenomorum,  Doxococcus,  Chilomonas,  and  Bodo.  Subsequent 
researches  led  him  to  add  the  genus  Chloraster,  and  to  remove  Polytoma  in 
order  to  unite  it  mth  a  newly  discovered  genus,  named  by  him  Spondylomorum, 
in  a  distinct  family,  the  ffydromorina.  This  family,  however,  deserves  no 
special  consideration,  but  wiU  fall  within  the  compass  of  our  general  remarks 
on  the  Monadina,  as  will  also  the  genus  Anthojphysa,  in  accordance  with  the 
results  of  Cohn's  researches.  (See  Part  IL,  Systematic  History  of  Monadina.) 


OF  THE  PHTTOZOA.  131 

Very  little  observation  and  reflection  will  soon  convince  the  student  that 
the  members  of  this  group  of  beings  can  be  distinguished  by  no  such  constant 
definite  characters  as  suffice  to  establish  genera  and  species  with  any  pre- 
cision ;  their  history  is  too  imperfectly  known,  and  their  individuality  is  un- 
proved. If  they  make  their  appearance  in  a  fluid,  it  is  only  transitory ;  for 
they  are  soon  replaced  by  a  different  series  of  existences,  and  direct  observa- 
tion has  shown  many  of  them  to  be  no  other  than  transitional  phases  of  life 
of  other  organisms.  Thus,  Dujardin  advances  as  an  apology  for  his  attempted 
classification  of  Monadina,  that  the  generic  distinctions  he  has  essayed  to 
make  "  are  entirely  artificial,  and  simply  intended  to  facilitate  the  naming  of 
Infusoria  which  may  have  been  met  Avith  in  any  particular  infusion,  but 
which,  when  better  known,  may  prove  in  some  instances  mere  varieties  of  one 
and  the  same  species "  (Hist.  lufus.  p.  273).  Siebold  entirely  rejects  this 
family  of  Monadina  from  the  Infusoria,  believing  them  only  embryonic  forms, 
and  chiefly  zoospores  of  Confervae,  &c.  (Anat.  d.  luirheUos.  Tliiere,  1848, 
p.  8).  In  so  doing  he  has  had  many  approvers, — among  them  the  eminent 
natiu-alist  M,  Agassiz,  who  thus  writes: — ''Recent  investigations  upon  the 
so-called  Anentera  have  satisfactorily  sho^ii,  in  my  opinion  and  in  that  of 
most  competent  observers,  that  this  type  of  Ehrenberg's  Polygastrica,  without 
gastric  cavities  and  without  alimentary  tube,  are  reaUy  plants  belonging  to 
the  order  of  xilgse  in  the  widest  extension  of  this  group,  while  most  of  the 
Monas  tribe  are  merely  moveable  germs  of  various  kinds  of  other  Algae  " 
(A.  N.  H.  1850,  vi.  p.  156).  Nevertheless  the  character  of  this  treatise  renders 
it  necessary  for  us  to  present  Ehrenberg's  views  of  organization.  According  to 
these,  "■  the  Monadina  are  illoricated,  Tvith  a  homogeneous  body,  and  no  external 
appendages  except  cilia,  having  many  separate  gastric  sacs  or  vesicles,  but 
no  alimentary  canal  connecting  them,  and  a  bisexual  or  hermaphrodite  pro- 
pagative  system.  They  multiply  by  simple  and  complete  self-division  of  the 
body  into  two,  foui',  or  more  indi\'i duals.  The  uniformity  or  unvarying 
external  form  may  be  considered  one  of  the  principal  characteristics  of  the 
family  ;  for  no  one  of  the  Monadina  can  voluntarily  alter  the  shape  of  its 
body,  nor  can  it  extend  any  portion  of  it  and  then  contract  it  again.  Pro- 
pagation by  ova  is  assiuned  of  all  the  Monadina,  and  by  living  young,  or 
vivij)arous  reproduction,  in  Monas  vivijxira.  Some  of  them  have  an  eye- 
speck,  but  no  vascular  or  respiratory  system  is  discernible." 

Although  the  general  characters  of  the  Monads  are  rightly  delineated  in 
this  account,  yet  the  peculiar  hypothesis  implied  will  not  at  the  present  day 
find  supporters.  Dujardui  denied  the  presence  of  an  enveloping  skin  or 
integument ;  and  if  a  separable  distinct  tunic  is  intended,  that  natiu^alist  is  in 
the  right ;  yet  it  would  be  an  error  to  ignore  the  existence  of  a  layer  of 
different  consistence  to  the  contained  matter,  i.  e.  of  a  pellicle.  Besides  such 
a  peUicle,  some  Monads,  at  least,  have  the  power  of  secreting  around  them- 
selves a  second  external  envelope  or  cyst,  or  of  '  encysting '  themselves. 
When  thus  transfomied,  Ehrenberg  would  not  recognize  them  as  Monadina, 
but  as  Cryptomonadina,  or  loricated  Monadina.  Hence  one  source  of  error 
in  his  distribution  of  these  minute  microscopical  forms. 

The  invariability  of  form  and  incapability  of  extending  and  retracting  the 
body,  so  prominently  advanced  as  special  features  of  Monadina,  Dujardin 
does  not  admit  as  facts,  but,  on  the  contrary,  states  them  to  be  without 
integ-ument,  and  susceptible  of  adhesion  to  one  another  or  to  foreign  par- 
ticles, and  to  be  capable  of  stretching  themselves  out  so  as  to  alter  their  form, 
even  so  far  as  to  produce  an  expansion  which  may  at  times  be  mistaken  for 
another  filament.  Some  Monadina,  he  adds,  can,  while  freely  swimming 
about,  change  theii'  fonn,  and  by  so  doing  approach  the  character  of  Amoehce. 

k2 


132  GENERAL  HISTORY  OF  THE  INFUSORIA. 

This  power  of  the  Monadina  to  become  polymorphic  is  likewise  alluded  to  by 
Mr.  Carter  (A.  N.  H.  1856,  vol.  xviii.  p.  122). 

According  to  modem  phraseology,  we  might  describe  these  beings  as  com- 
posed of  protoplasm  enveloped  by  a  pellicle,  and  as  having  an  extension  of  the 
protoplasmic  mass  developed  in  the  form  of  a  flagelliform  filament,  to  serve 
as  a  locomotive  organ.  The  presumed  gastric  cells  are  the  vacuoles  in  the 
protoplasm  hollowed  out  spontaneously  within  it,  and  ever  changing  in  posi- 
tion and  magnitude.  Dujardin  affirms  that  they  at  times  form  near  the 
surface,  open  externally,  and  on  again  closing  up  include  foreign  particles 
which  have  found  their  way  within  them,  and  that  they  thus  act  in  some 
measure  as  instniments  of  nutrition  in  aid  of  the  general  process  carried  on 
by  endosmose  or  absorption. 

That  the  Monadina  had  a  mouth  communicating  with  the  '  gastric  sacs,' 
Ehrenberg  believed  to  be  demonstrated  by  the  introduction  of  particles  of 
colour  within  those  cavities  from  without.  "  The  nutritive  apparatus,"  he 
tells  us,  '^  may  be  readily  seen  in  some  species  in  their  ordinary  state  (for 
instance,  in  Monas  guttula  and  M.  vivipara),  whilst  in  others  it  is  proved  by 
using  coloured  food  (for  example,  in  Monas  Termo  and  31.  socialis).  It  consists 
of  several  distinct  or  separate  cells  (from  8  to  20),  not  all  filled  at  the  same 
time,  but  one  after  the  other.  These  are  always  invisible  when  empty,  but 
when  filled  with  limpid  fluid  appear  hke  so  many  lucid  vesicles."  Cohn  states 
that  he  can  confirm  the  accuracy  of  Ehrenberg's  observation  of  the  entrance 
of  colouring  particles  into  some  Monads,  and  therefore  inclines  to  the  belief 
that  such  examples  must  have  an  oral  apertiu'e,  and  be  of  an  animal  nature 
{Entiv.  p.  162).  To  this  he  adds  that  many  of  the  Monads  of  Ehrenberg 
may  really  be  swaiin-spores  of  microscopic  Eungi ;  still  he  holds  it  to  be 
improbable  that  true  plant-cells  should  take  up  within  them  indigo-particles. 
So,  at  p.  148,  when  remarking  on  the  precise  similarity  in  all  visible  features 
of  the  swarm-spores  of  Achlya  jprolifera  with  Trichodina  grandinella  and 
Bodo  saltans,  he  says  Ehrenberg's  Bodo  eats  indigo -particles,  which  is  not 
the  case  with  the  form  in  question. 

What  weight  should  be  attached  to  these  observations  of  the  reception  of 
molecules  of  colour  within  Monadina,  as  pro\dng  a  mouth  and  stomach-cells, 
must  be  decided  by  further  experiments.  Sometimes,  possibly  enough,  when 
the  minuteness  of  the  objects  concerned  is  remembered,  the  colour-grains 
have  not  actually  been  within,  but  above  or  below  them,  on  the  surface  ;  and, 
again,  other  experimenters  damage  the  force  of  the  argument  by  affirming  that 
they  have  succeeded  in  getting  colour  taken  up  by  Diatomeae,  and  by  undoubted 
vegetable-cells.     This  statement  has  been  made,  among  others,  hy  Braun. 

After  the  consideration  given  in  a  previous  page  to  the  nature  of  the 
supposed  eye -specks,  further  reference  to  them  here  is  uncalled  for. 

Concerning  the  modes  of  multiplication,  the  great  Berhn  micrographer  is 
correct  in  his  account  of  the  process  of  fission ;  yet  few  will  join  with  him  in 
describing  ova  and  vi^dparous  reproduction  among  Monadina,  or  in  imagining 
distinct  male  and  female  generative  organs — in  other  words,  an  hermaphrodite 
(monoecious)  structure.  Certainly  the  phenomenon  Weisse  witnessed  in 
Chlorogonmm  euchlorum,  of  the  development  and  subsequent  discharge  of  a 
host  of  young  germs,  might  be  termed  viviparous  reproduction  ;  but  it  is  no 
other  than  the  usual  plan  of  development  of  microgonidia  among  Algae.  In 
fact,  no  one  has  witnessed  the  development  and  extrusion  of  germinal  ova, 
although  the  breaking  up  of  the  substance  of  Monadina  into  minute  particles, 
by  the  process  of  diffluence  or  by  often-repeated  fission,  and  the  reproduction 
of  gonidia  may  be  constantly  noticed.  Perty  so  far  countenances  Ehrenberg's 
views  as  to   affirm  the  development  of  Monas  vivipara  and  of  M.  Lens  by 


OF  THE  PHYTOZOA.  133 

germs  which,  whilst  still  wdthin  the  i3arent-cell,  exhibit  an  oscillating  move- 
ment. He  would  even  extend  the  phenomenon  to  all  Monads  ;  yet  we  regard 
it  as  no  other  than  that  of  gonidial  develojDment.  Another  circumstance 
this  same  writer  points  out  is,  that  in  Monas  Lens  and  allied  forms,  the 
anterior  individual  produced  by  transverse  self- division  is  3  to  4  times 
smaller  than  the  posterior,  and  that  in  Tetramitus  rostratus,  where  longi- 
tudinal fission  prevails,  the  right  segment  is  much  less  than  the  left.  It  is 
this  unequal  segmentation  of  Monads  which  induced  Dujardin  to  represent 
their  multiplication  to  occui*  by  the  detachment  of  a  lobe  or  of  an  expansion, 
and  not  by  actual  self- division :  but  in  our  opinion  such  a  distinction  is  too 
refined  ;  for  the  term  self- division  has  a  meaning  wide  enough  to  embrace  the 
phenomenon  of  fission  whether  by  equal  or  unequal  segments ;  indeed  the 
latter  variety  is  sufficiently  common  where  no  difficulty  is  felt  in  reckoning 
it  a  mode  of  self-fission. 

In  further  elucidation  of  this  act  of  segmentation  in  Monadina,  we  may  add 
the  following  remarks  from  Schneider  {A.  N.  H.  1854,  xiv.  p.  327-328). 
Speaking  of  Chilomonas Paramecium,  this  author  writes — ''Whatever  number 
of  these  animals  may  be  observed,  no  trace  of  division  will  ever  be  remarked 
in  them.  Veiy  rarely  we  may  see  two  individuals  adhering  by  their  middle, 
evidently  produced  by  a  longitudinal  division.  We  shall  endeavour  to  ex- 
plain this.  On  close  examination,  one  or  two  reddish  lines  may  be  seen 
running  backwards  from  the  bottom  of  the  indentation,  which  might  readily 
be  taken  for  organs  lying  in  the  interior  of  the  body.  I  have  convinced 
myself,  however,  especially  by  the  comparison  of  the  process  of  division  in  a 
species  of  Bodo,  that  these  lines  indicate  furrows,  which  gradually  divide  the 
whole  by  cutting  deeper  and  deeper  on  each  side.  As  during  this  process 
the  animal  undergoes  no  change  of  form,  except  in  becoming  a  little  broader, 
and  the  division  takes  place  along  its  whole  length,  the  process  must  readily 
escape  obseiwation.  The  anterior  end  is  always  a  little  thicker  ;  the  fuiTows 
consequently  are  deeper  and  more  distinctly  recognizable  in  that  part.  With 
a  suitable  arrangement  of  the  microscope,  it  is  evident  that,  the  two  furrows 
being  looked  at  simultaneously,  two  reddish  lines  are  seen.  It  is  only  in 
rare  cases,  when  the  division  has  taken  place  more  slowly  in  some  j^articular 
spot,  that  the  two  specimens  must  endeavour  to  tear  themselves  free,  and 
thus,  by  twisting  in  contrary  dii'ections,  draw  our  attention  to  them.  That  the 
process  of  division  is  effected  in  a  similar  manner  in  other  Monadina,  appears 
from  an  observation  of  Ehrenberg's  upon  Cryptomonas  cylindrica  (p.  42)  : — '  I 
saw  no  instance  of  constriction  or  fissation ;  but  two  individuals  were  swimming 
whilst  adhering  together,  which  might  lead  one  to  suppose  that  a  longitudinal 
division  from  behind  forwards  had  taken  place.'  And  it  is  not  improbable 
that  the  specimen  represented  by  him  on  tab.  ii.  fig.  xix.  2,  with  two  seminal 
glands  (nuclei?)  and  two  longitudinal  lines,  was  in  the  act  of  division." 

That  Monads  are  only  the  first  and  simplest  stage  of  existence  of  numerous 
animal  and  vegetable  organisms,  is  an  undoubted  fact ;  but,  if  we  may  credit 
some  observers,  their  transformations  are,  in  certain  cases,  very  extraordi- 
nary. Thus,  Stein  represents  the  nucleus  of  encysted  VorticeUce  to  break 
up  into  Monads  (the  Monas  colpoda  or  M.  scintillans),  which  by  various  in- 
termediate stages  become  reconverted  into  VorticeUce.  So,  again,  Hartig 
{J.  M.  S.  1855,  p.  52)  and  Carter  (A.  N.  H.  1856,  xviii.  p.  122)  represent 
the  conversion  of  Monads  into  Amoebce,  the  former  by  a  coalescence  of  a  group, 
the  latter  by  the  simple  assumption  by  individual  Monads,  on  losing  their 
cilia,  of  polymorphism.  Lastly,  the  resemblance  of  the  zoospores  of  Achlya 
to  Bodo  saltans  has  already  been  mentioned  to  be  complete  in  ever}'  respect, 
save  in  the  non-imbibition  of  colouring  particles. 


134  GENERAL  HISTORY  OE  THE  INFUSORIA. 

Few  details,  excepting  those  comprehended  in  attempted  generic  and  specific 
characters,  have  been  published  by  observers  on  the  genera  of  Monadina  in 
general.  Uvella,  AntliopTiysa,  and  Polytoma  have,  however,  received  more 
attention  than  the  rest ;  and  the  results  arrived  at  we  wiU  here  abstract. 

Uvella  is,  in  the  system  of  Ehrenberg,  characterized  by  the  aggregation  of 
numerous  Monads  (XYIII.  3),  severally  imdistinguishable  from  simple  isolated 
species  (XYIII.  4),  into  spherical  or  mulberry-like  masses,  freely  moveable  in 
the  surrounding  liquid.  The  individuals,  hke  those  of  the  genus  Monas,  have 
a  locomotive  organ,  consisting  perhaps  of  two  cilia,  situated  close  to  the 
mouth  at  the  anterior  extremity,  but  neither  tail  nor  eye-speck.  They  pro- 
gress in  the  dii-ection  of  the  longer  axis  of  the  body,  and  are  capable  of  com- 
plete self- division.  In  the  best-examined  species,  U.  glaucoma,  Ehrenberg 
represented  large  internal  vesicles,  a  double  filiform  proboscis,  and  a  great 
number  of  small  coloiuiess  granules,  conceived  to  be  ova,  lying  between  the 
nutritive  sacs.  He  supposed  it  to  propagate  both  by  transverse  and  longitu- 
dinal self-fission,  and  stated  that,  on  feeding  it  with  indigo,  as  many  as  twelve 
stomachs  were  filled,  and  that  sometimes  little  blue  particles  like  imdigested 
matter  might  be  seen  voided  from  its  mouth,  and,  lastly,  that  he  had  dis- 
cerned several  green  Monads  within  its  body,  which  it  had  eaten,  and  which 
proved  it  to  subsist  on  prey  directly  transmitted  into  its  interior.  Indi\idual 
Monads,  he  added,  can  detach  themselves  from  the  mass,  live  apart  for  a  time, 
and  again  become  members  of  the  colony. 

This  accoimt  was  rejected  by  Dujardin,  who  denied  the  existence  of  a 
mouth,  of  gastric  cells,  and  of  ova,  and  doubted  the  occurrence  of  true  self- 
division.  He  likewise  never  witnessed  the  re-attachment  into  masses  of  the 
Monadiform  individuals  after  being  once  separated,  but  beheved  that  the  re- 
union of  certain  Monads,  occasionally  observed  in  infusions  rich  in  these  beings, 
is  a  fortuitous  result  of  the  glutinous  nature  of  their  siu^face. 

These  strictures  of  Dujardin  are,  without  doubt,  in  general  very  just.  The 
supposed  mouth  is  the  clear  space  seen  at  the  anterior  extremity  of  most 
unicellular  organisms,  whilst  the  supposed  stomach-sacs  are  no  other  than 
chlorophyU-vesicles  or,  otherwise,  vacuoles.  The  green  Monad-like  cells  seen 
by  the  Berlin  micrographer  were  probably  starch-  or  chlorophyU-ceUs,  or,  it 
may  be,  gonidia ;  and  it  was  a  mere  assumption  to  represent  them  as  swal- 
lowed particles. 

Itzigsohn,  Cohn,  and  Mr.  Busk  make  Uvella,  or  at  least  an  organism  like 
it  in  all  essential  external  features,  a  phase  of  existence  of  vegetable  struc- 
tures,— the  first-named  of  Oscillatoria  (J.  M.  S.  1854,  p.  190),  the  second  of 
Protococcus,  the  last  of  Volvox.  Itzigsohn  describes  the  Euglena-i^'hase  of 
Oscillatoria  as  breaking  up  into  microgonidia  which  collect  themselves  in  colo- 
nies, resembling,  according  to  the  presence  or  absence  of  coloured  contents, 
Uvella  atomus,  U  glauca,  Bodo,  &c.  Cohn's  views  are  sufficiently  represented 
in  our  remarks  on  Protococcus  (see  p.  124),  and  need  not  be  here  repeated. 
Busk  represents  the  ciliated  zoospores  of  Volvox  {T.  M.  S.  i.  p.  39)  as  sub- 
dividing into  minute  ciliated  cells  {i.  e.  microgonidia),  which  "  form  by  their 
aggregation  a  discoid  body,  in  which  the  separate  fusiform  cells  are  connected 
together  at  one  end,  and  at  the  other  are  free,  and  furnished  each  with  a 
single  cilium.  In  this  stage  these  compound  masses  become  free  and  swim 
about  in  the  water,  constituting  in  fact  a  species  of  the  genus  Uvella,  or  of 
Syncrypta  of  Ehrenberg."  If  these  representations  be  correct,  Uvella  is  but 
a  phase  of  existence  of  Volvocina  and  of  Oscillatoria,  and  probably  of  other 
plants.  If  this  be  not  allowed,  then  the  alternative  remains,  of  supposing 
both  a  vegetable  and  an  animal  organism  partaking  like  characters  and 
qualities. 


OF  THE  PHTTOZOA.  135 

The  genus  Anthophysa  (XXYI.  2)  has  been  more  particularly  studied  by 
Dujardin  and  Cohn.  Ehrenberg  pro\dsionally  placed  it  among  the  Vortlcel- 
lina  as  a  doubtful  species  of  Ejpistylis,  as  he  was  unable  to  determine  whether 
it  possessed  a  wreath  of  cilia  at  its  head  or  only  a  single  filament :  if  the 
latter,  he  remarked,  it  would  belong  to  the  Monads.  Mtiller,  its  discoverer, 
had  indeed  more  rightly  seized  on  its  true  position  by  associating  it  mth 
Volvox.  Dujardin  subsequently  made  out  its  affinity  with  Uvella,  and  adopted 
M.  Boiy  de  St.  Vincent's  generic  appellation  for  it.  In  this  determination  of 
its  position  Dujardin  has  the  weighty  support  of  Cohn,  who  has  recently  sub- 
mitted it  to  careful  examination.  Dujardin's  description  is  very  accm-ate,  and 
will  serve  our  purpose.  ''  It  is  very  difficult,"  he  writes,  "  to  distinguish  a 
Uvella  from  a  free  Anthophysa ;  but  no  difficulty  will  exist  if  some  of  the 
branching  supports  of  the  latter  are  seen  in  the  siuTounding  fluid.  These 
supports  have  an  arborescent  figure  irregularly  branched,  are  brownish  at  the 
base,  but  clearer  and  even  diaphanous  at  the  extremities  of  the  branches, 
which  are  themselves  nodular  or  rugged ;  they  are  secreted  by  the  animals, 
and  are  found  affixed  to  the  sides  of  the  vessel  in  which  water  containing 
these  Infusoria  has  been  but  recently  placed.  Each  group  of  animalcules  is 
at  fii^st  fixed  on  the  diaphanous  extremity  of  the  branch  which  it  has  secreted 
(XXYI.  2) ;  but  any  agitation  of  the  liquid,  or  sudden  shock,  easily  detaches 
it,  and  it  then  moves  in  a  revoMng  manner  in  the  hquid.  This  movement  is 
the  result  of  the  simultaneous  action  of  the  flagelliform  filaments  with  which 
each  individual  of  the  colony  is  provided.  When,  moreover,  a  group  has  been 
detached,  whether  accidentally  or  spontaneously,  isolated  individuals  may  be 
seen  moving  about  precisely  like  Monads  with  a  single  filament.  The  branch- 
ing support  is  at  first  soft  and  glutinous,  but  gradually  acquires  consistency 
and  a  brownish  and  homy  aspect,  when  it  seems  no  longer  to  participate  in 
the  life  of  the  animalcules,  and  recalls  to  the  mind  the  construction  of  the 
fibrous  skeleton  of  certain  sponges.  It  is  conceivable  either  that  the  branches 
themselves  bifurcate,  or  that  the  division  is  the  consequence  of  the  multipli- 
cation by  fission  of  the  groups  of  animalcules." 

Cohn  has  little  to  add  to  this  account.  He  describes  the  probably  chitinous 
stem  to  be  invested  externally  by  a  brownish  mucilaginous  layer ;  and  also 
finds  that  from  2  to  8  and  fi'om  that  to  20  Monads  may  be  aggregated  at  the 
extremity  of  the  branches.  Frequently  a  branch  is  bare  at  its  point,  having 
lost  its  animal  colony ;  and  it  would  seem  that  the  whole  of  the  groups  are 
in  succession  throvm  off  and  dispersed  as  free  Monads  and  as  UveUa-like 
groups.  Cohn,  indeed,  intimates  his  belief  that  Uvella  and  Anthophysa  are 
not  actually  distinct  genera,  but  mere  representatives  of  two  conditions  of 
the  same  animalcule.  Unlike  Ehrenberg,  he  failed  to  get  indigo -particles  taken 
up  by  the  Uvella-like  beings. 

Before  arriving  at  the  conclusion  that  Anthophysa  is  no  other  than  Uvella 
Uva  seated  on  a  branching  stem,  and  of  animal  nature,  he  canvasses  the 
question  if  this  organism  be  not  rather  the  mycchum  of  a  Fimgus  bearing  its 
spores  at  the  extremities  of  its  branches,  and  decides  against  the  supposition 
chiefly  from  the  irregular  and  indefinite  multiplication  of  the  monadiform 
members  of  the  groups,  from  the  detachment  of  these  en  masse  instead  of  by 
separate  spores,  and  from  the  want  of  evidence  to  show  that,  when  these 
UveUa-like  groups  are  detached,  they  assume  the  quiescent  or  '  still '  condition, 
and  germinate  into  an  arborescent  mycelium  like  the  parent,  to  develope  in  its 
turn  terminal  masses  of  spores. 

The  branching  stem  has  been  described  by  Kiitzing  and  others  as  a  micro- 
scopical Fungus  (Conferva),  under  the  name  of  Stereonema,  and  several  species 
instituted ;  but  Cohn  points  out  its  analogy  with  the  pedicle  of  Gomphonema 


136  GENERAL  HISTORY  OF  THE  INFUSORIA. 

and  other  Diatomeae,  in  which  both  the  branched  stem  and  the  beings  it 
supports  are  ahke  part  and  parcel  of  the  same  organic  structni'e.  He  has 
met  with  fibres  supporting  but  one  or  two  Uvella -bundles,  and  others  like 
little  trees  bearing  ten  such.  The  consistence  of  the  stem  is  such  that  it 
resists  the  action  both  of  sulphuiic  acid  and  of  solution  of  potash. 

One  other  genus  oi  Monadina,  viz.  Polytoma  (XVIII.  5),  has  received  special 
attention  from  Schneider,  Cohn,  and  Perty ;  it  nevertheless  still  remains  in 
that  neutral  ground  claimed  both  by  zoologists  and  botanists.  Ehrenberg  at 
first  placed  it  in  the  family  Monadina ;  but  having  subsequently  met  with  a 
similar  form,  Sponclylomorum,  he  instituted  a  new  family,  Uydromorina,  to 
include  the  two  genera,  and  set  forth  as  its  chief  differential  characters  the 
aggregate  or  compound  nature  of  its  members,  dependent  on  imperfect  fission. 
He  asserted  also  that  individuals  set  free  from  the  groups  enter  on  the  same 
cycle  of  fission  and  compound  development,  and  form  similar  groups.  Foly- 
toma  was  described  to  be  destitute  of  an  eye-speck,  to  have  a  truncated 
mouth  and  a  dehcate  double  flagelliform  proboscis,  and,  from  repeated  incom- 
plete self- division,  to  form  a  mulberry-like  mass,  which  eventually  breaks  up 
into  isolated  Monads.  "  The  ova,"  he  adds,  "  from  their  minuteness  and  the 
want  of  transparency,  have  hitherto  eluded  observation  (XYIII.  5)  :  but  the 
alimentary  organization  is,  on  the  contrary,  clearly  demonstrable ;  for  al- 
though for  a  long  time  the  entrance  of  coloured  food  could  not  be  displayed, 
yet  at  length,  by  using  a  magnifying  power  of  600  to  800  diameters,  the 
entrance  of  indigo-particles  into  their  bodies  was  rendered  evident."  In 
addition  to  these  structures,  he  mentions  a  large  contractile  vesicle  as  a  male 
sexual  organ,  and  a  white  spot  at  the  anterior  part  of  the  body  as  a  seminal 
gland.  In  all  essential  particulars  the  associated  genus  Spondylomorum  was 
stated  to  agree  with  it,  except  in  having  a  dorsal  eye- speck. 

Dujardin  confesses  his  inability  to  distinguish  by  any  definite  characters 
between  Uvella  and  Polytoma ;  he  would  seem,  however,  not  to  have  per- 
sonally investigated  the  latter.  Cohn,  after  examining  both,  declares  them 
to  be  identical  in  all  particulars  except  that  in  Polytoma  chlorophyll  is  absent, 
and  that  it  inhabits  decomposing  fluids  along  with  Chlamydommias  j)ulviscu- 
lus.  However,  it  is  to  Schneider  that  we  are  indebted  for  the  most  complete 
history  of  this  organism  (Inaugural  Dissertation,  ''  Symholce  ad  Infusorium 
historiam  naturalem,'"  Berlin,  1853,  translated  in  A.  N.  H.  1854,  xiv.  p.  321). 
We  extract  the  foUo^dng  copious  details  from  the  translation : — "  Polytoma 
Uvella  is  of  an  oval  form  ;  it  is  from  -g^th  to  ^\j-th  of  an  inch  long,  and  about 
half  that  width.  At  one  end,  which,  mth  Ehrenberg,  we  will  call  the  an- 
terior extremity,  it  bears  two  filaments  as  long  or  longer  than  the  body. 
"When  the  living  animal  is  examined  under  a  magnifying  power  of  300  dia- 
meters, the  body  appears  to  be  bounded  by  a  simple  outhne.  But  in  many 
instances,  and  especially  when  a  large  specimen  can  be  found  at  rest,  it  may 
be  seen  that  the  internal  substance  of  the  body  is  surrounded  by  a  thin  and 
perfectly  clear  membrane,  from  which  it  is  separated  by  a  distinct  space. 
When  the  investing  membrane  is  more  closely  attached,  its  existence  may 
always  be  demonstrated  by  the  employment  of  reagents  to  produce  the  con- 
traction of  the  substance  of  the  body  :  chromic  acid  and  solution  of  iodine  in 
chloride  of  zinc  are  the  best  substances  to  employ,  the  latter  especially,  as  it 
at  the  same  time  communicates  a  brown  colour  to  the  internal  sac  (PI.  XX. 
fig.  2).  Under  certain  circumstances,  the  investing  membrane  divides  into 
minute  granules,  assuming  when  viewed  from  the  side  a  regular  necklace- 
like appearance  (fig.  8).  A  reproduction  of  the  membrane  then  takes  place. 
The  substance  of  the  body  is  perfectly  clear,  with  the  same  refractive  proper- 
ties as  that  of  Amwha.     About  the  middle  lies  a  clear  globular  nucleus,  sur- 


OF  THE  PHYTOZOA.  137 

rounded  by  a  narrow  reddish  halo  (figs.  1,  2,  3,  8).  Dilute  acids  render 
this  more  distinct.  At  the  anterior  extremity,  close  to  the  margin,  there  are 
two  reddish  vesicles,  the  contractions  of  which  may  easily  be  recognized  in 
individuals  in  a  state  of  repose.  The  hinder  extremity  always  contains  a  mass 
of  granules  with  dark  outlines,  which  are  not  altered  by  acetic  acid.  A  weak 
solution  of  iodine  in  iodide  of  potassium  gives  them  a  deep  blue  colour,  gene- 
rally verging  upon  black,  as  it  is  difficult  to  hit  the  right  quantity  of  the  reagent 
to  be  added.  The  fine  blue  colour  is  better  attained  by  the  addition  of  dilute 
solution  of  iodine  in  chloride  of  zinc,  as  with  this  the  granules  become  shghtly 
liquefied,  and  when  left  standing  for  some  time  even  form  a  blue  paste.  Muriatic 
and  sulphuric  acids  also  dissolve  them,  so  that  the  subsequent  addition  of  iodine 
gives  the  whole  body  a  blue  colour.  When  the  putrefaction  of  the  infusion 
is  going  on  very  rapidly,  the  granules  fill  the  entire  body.  They  are  not 
arranged  in  balls  like  the  nutritive  matter  in  the  bodies  of  other  Infusoria ; 
and  it  is  by  no  means  probable  that  they  are  taken  in  from  the  exterior. 
Besides  the  two  contractile  vesicles,  single,  non- contractile,  reddish  vacuoles 
are  seen  scattered  through  the  substance  of  the  body. 

"  The  starch-like  granules  are  often  converted  into  an  indigo-blue  pig- 
ment, which  is  then  partially  dissolved,  and  colours  the  whole  parenchyma. 
Such  specimens  as  these  still  retain  the  power  of  division,  so  that  there 
can  be  no  doubt  as  to  their  identity  with  Polytoma  Uvella.  Individuals 
were  also  frequently  met  with  of  which  the  substance  of  the  body  was  of 
a  uniform  green  colour,  but  which  in  other  respects  agreed  exactly  with 
Polytoma. 

"  Deviations  from  this  normal  form  never  occur  singly  in  the  same  vessel, 
but  always  make  their  appearance  simultaneously  in  a  great  number  of  indi- 
viduals. Certain  peculiarities  of  their  abode  appear  therefore  to  have  an 
influence  upon  the  form.  Very  compressed  forms  are  rare.  However,  it  not 
unfrequently  happens  that,  whilst  the  investing  membrane  retains  its  normal 
form,  the  substance  of  the  body  is  not  equally  distributed  in  its  interior. 
Sometimes  it  Hes  to  one  side,  so  as  to  fill  only  half  the  interior  of  the  sac ; 
sometimes  it  is  entirely  collected  in  the  anterior,  and  sometimes  in  the  pos- 
terior extremity ;  in  the  latter  case  it  is  connected  with  the  anterior  extre- 
mity by  a  slender  filament  (fig.  14).  In  infusions  in  which  fermentation  has 
long  ceased,  and  which  contain  a  large  quantity  of  brown  humus -hke  matter 
but  very  small  portions  of  nitrogenous  substances  in  solution,  the  two  last 
modifications  of  the  parenchyma  are  most  frequently  met  mth.  At  the  same 
time  the  starch-like  granules  disappear,  the  substance  of  the  body  acquires  a 
darker  fatty  outline,  and  finally  disappears  with  formation  of  the  well-known 
large  vacuoles. 

*'  The  movements  of  Poli/toma  are  the  same  as  those  usually  ascribed  to 
organisms  furnished  with  two  filaments.  "Whilst  in  motion  the  filaments  are 
always  in  front,  the  animal  rotates  upon  its  axis,  and  this  again  describes 
circular  \dbrations  upon  a  central  point.  If  a  movement  in  the  opposite 
direction  is  taking  place,  the  animal  is  endeavouring  to  turn  the  anterior 
extremity ;  and  until  this  is  eff'ected  it  swims  backwards.  When  a  drop  of  the 
infusion  has  been  left  for  a  few  minutes  upon  a  glass  plate  covered  over  with 
a  piece  of  thin  glass,  a  considerable  number  of  the  animals  will  be  found 
attached  to  both  glasses  by  their  anterior  extremity ;  the  filaments  are  free, 
and  it  is  probably  by  their  vibration  that  the  hinder  extremity  is  made  to 
oscillate  in  the  direction  of  the  plane  of  the  two  filaments.  They  collect  in 
the  same  manner  in  crowds  upon  aquatic  plants,  as  well  as  upon  the  sides  of 
the  vessel  containing  them.  Their  mode  of  attachment  is  stiU  unintelligible 
to  me.    In  any  case,  some  contrivance  for  this  purpose,  however  simple,  must 


138  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

exist,  either  between  the  two  filaments,  or  at  the  side  of  their  points  of  issue 
from  the  membrane. 

"  During  the  swarming-state,  a  division  of  the  substance  of  the  body  goes  on 
uninterruptedly  at  all  hours  of  the  day.  The  different  stages  of  this  process 
follow  one  another  with  greater  or  less  rapidity  in  proportion  as  the  conditions 
of  nutrition  are  more  or  less  favourable.  Soon  after  the  commencement  of  fer- 
mentation in  an  infusion,  the  rate  of  increase  attains  its  maximum ;  it  then 
diminishes  as  the  fermentation  ceases,  the  offspring  at  the  same  time  undergo- 
ing a  diminution  of  size. 

"The  commencement  of  the  process  of  division  is  indicated  by  the  uniform 
distribution  of  the  granular  substance.  A  constriction  of  the  substance  then 
takes  place,  usually  commencing  on  one  side ;  by  this  the  body  is  divided 
into  two  parts,  which  are  still  enclosed  in  the  iminjured  investing  membrane. 
Simultaneously  with,  or  perhaps  before  the  completion  of  this  bisection,  the 
nucleus  also  divides  (fig.  3).  Although  no  constriction  of  the  nucleus  was 
ever  noticed,  nothing  certainly  was  observed  to  contradict  the  supposition 
that  the  second  nucleus  was  produced  in  this  manner.  The  two  halves  then 
become  constricted  from  their  sui'faces  of  contact,  in  such  a  manner  that  the 
constriction  of  one  half  crosses  that  of  the  other  at  right  angles  (fig.  4).  To 
every  depression  thus  produced  on  the  one  side  there  is  a  corresponding  ele- 
vation of  the  other.  The  quadrisection  (figs.  9, 12)  then  takes  place  suddenly 
as  if  by  cutting,  and  mthout  any  appearance  of  a  circular  constriction,  each  por- 
tion containing  its  jn'oper  nucleus.  The  divisions  now  acquire  an  oval  form, 
and  arrange  themselves  in  such  a  manner  that  the  ends  of  the  posterior  pair, 
which  are  turned  towards  the  middle,  alternate  with  those  of  the  anterior 
pair  in  the  same  place  (fig.  12).  In  very  favourable  circumstances  (as  for  in- 
stance at  the  commencement  of  fermentation),  a  third  division  into  eight 
parts  takes  place,  each  division  being  still  furnished  vi^th  a  nucleus.  As  a 
general  rale,  however,  the  young  individuals  acquii^e  filaments  soon  after  the 
quadrisection,  and  move  about  in  various  directions  within  the  investing  mem- 
brane, until  this  biu^sts  and  the  young,  which  are  exactly  like  the  mother 
except  in  their  smaller  size,  are  set  free.  In  favourable  circumstances  the 
empty  membrane  remains  vrith  the  two  filaments.  After  the  division  of  the 
substance  into  four  or  eight  parts,  the  investing  membrane  is  always  visible 
without  the  employment  of  any  reagents.  This  has  not  escaped  Ehrenberg 
(loc.  cit.  and  tab.  i.  xxxii.)  ;  he  explains  the  appearance  as  a  consequence  of  a 
superficial  constriction.  The  filaments  of  the  parent  always  appear  to  be  con- 
nected only  with  one  of  the  young  individuals,  although  this  is  less  distin- 
guishable in  the  present  mode  of  di\dsion  than  in  that  about  to  be  described. 
"  In  this  the  quadrisection  takes  place  in  another  manner.  After  bisection, 
the  two  portions  shift  their  position  in  such  a  manner  that  the  surfaces  of 
contact  form  a  distinct  angle  with  their  original  position.  If  this  change  of 
position  be  but  trifling,  the  quadiisection  goes  forward  nearly  in  the  manner 
just  described,  and  the  arrangement  of  the  developed  young  only  differs  as  far 
as  is  rendered  necessary  by  this  change  of  position  ffigs.  9,  12).  But  if  it  be 
more  considerable,  the  new  surfaces  of  division  run  parallel  to  each  other  and 
nearly  perpendicular  to  the  surfaces  of  contact  of  the  two  halves.  The  posi- 
tion of  the  young  individuals  is  then  completely  different  from  that  seen  in 
the  preceding  case  ;  all  four  lie  parallel  to  each  other,  with  their  longitudinal 
axis  oblique  as  regards  the  axis  of  the  whole  (fig.  10). 

"  This  difference  may  perhaps  be  explained  as  follows  : — Each  portion  has 
a  tendency  to  acquire  an  oval  form,  so  that  soon  after  the  bisection  the  ante- 
rior portion  extends  itself  posteriorly,  and  the  posterior  towards  the  front. 
When  sufficient  time  has  not  elapsed  for  the  one  dimension  to  predominate  over 


OF  THE  PHYTOZOA.  139 

the  other,  the  quadrisection  takes  place  as  in  the  former  case ;  but  when,  on  the 
other  hand,  one  dimension  has  become  predominant,  the  division  into  four  takes 
place  in  accordance  with  the  same  law  as  the  original  di\ision  into  two. 

'^  The  method  of  division  fii^st  described  is  always  met  with  in  the  early 
periods  of  an  infusion,  Avhich  are  most  favourable  to  the  development  of  the 
creatures.  Towards  the  end  the  latter  mode  alone  occurs.  This  phenomenon 
was  so  remarkable  that,  on  the  first  occasion  of  my  examining  an  infusion 
towards  the  close  of  its  action,  I  imagiaed  that  I  had  at  first  misunderstood 
the  mode  of  division. 

"  Under  certain  circumstances  the  individuals  pass  to  a  state  of  rest.  They 
are  then  completely  filled  with  the  starch-like  granules,  so  that  the  nucleus 
only  appears  as  a  reddish  spot.  The  substance  of  the  body  becomes  spherical, 
and  invests  itself  with  a  membrane  which  is  frequently  of  considerable  thick- 
ness (fig.  7).  In  this  state  I  have  never  observed  them  to  undergo  any  divi- 
sion or  any  other  change ;  and  when  diied  the  cysts  still  retain  their  contents. 
When  clear  water  is  poui'ed  over  them  they  do  not  return  to  hfe,  but  would 
probably  do  so  in  a  fermenting  infusion. 

''  The  mode  in  which  the  swarming  individuals  arrive  at  this  state  of  repose 
appears  to  be  as  follows : — The  filaments  are  gradually  shortened,  their  sub- 
stance collecting  at  the  free  extremity  in  the  form  of  a  small  knob,  until  at 
last  the  filiform  portion  entirely  disappears,  and,  in  place  of  the  filaments,  two 
vesicles  are  seen  at  the  anterior  extremity  of  the  investing  membrane.  I 
have  obsei-ved  a  similar  contractibility  of  the  substance  of  the  filaments  in  a 
Bodo  which  is  most  nearly  allied  to  Bodo  grandis,  Ehrbg.  As  this  possesses  not 
three  filaments  only,  as  seen  by  Focke  {Elir.  p.  34),  but  often  as  many  as  five, 
the  vesicles  produced  in  this  manner  cannot  easily  be  overlooked.  I  cannot, 
however,  state  with  certainty  whether  all  the  individuals  which  undergo  this 
change  invest  themselves  Tvith  cysts.  "WTien  infusions  containing  Pdytoma 
are  diied  slowly,  individuals  with  the  vesicles  just  described  are  found  in  the 
deposit,  but  no  cysts ;  and  it  is  not  impossible  that  such  indi\-iduals  may  assist 
in  the  continuation  of  the  species  in  some  other  way." 

After  some  valuable  notes  on  other  Infusoria,  Schneider'  concludes  his 
history  of  Polijtoma  by  the  following  arguments  for  its  animal  nature  : — 

*'  That  Polytoma  is  an  animal  may  be  maintained  upon  two  grounds. 

"  1.  The  constitution  of  the  investing  membrane. — As  soon  as  the  starch-like 
granules  have  been  destroyed  by  the  long  action  of  concentrated  sulphuric 
acid,  no  part  of  the  creatm^e  is  coloured  blue  by  iodine.  Now  we  have  no 
more  reason  for  believing  that  the  vegetable  cell-membrane  must  necessarily 
consist  of  cellulose,  than  that  the  animal  cell-membrane  should  not  consist 
of  that  substance,  so  that  we  are  still  compelled  to  seek  for  other  characters 
for  their  distinction.     These  would  be — 

"  2.  The  contractile  spaces. — A  statement  of  Cohn  has  ceriainly  rendered 
it  doubtful  whether  the  occurrence  of  these  is  henceforward  to  be  regarded  as 
an  essential  indication  of  an  animal  nature.  He  says,  '  On  the  other  hand, 
certain  genera  of  Algae  exhibit  a  stage  of  development  in  which,  in  external 
form,  in  the  absence  of  a  cellulose  membrane,  in  the  distinct  existence  of 
ciliaiy  organs  of  motion,  red  eye-like  spots,  vacuoles,  and,  according  to  a  very 
recent  discovery,  of  interned  pulsating  spaces,  they  undoubtedly  appear  very 
similar  to  the  Astomatous  Infusoria.'  If  these  pulsating  spaces  occur  only 
in  unicellular  Algae  provided  with  cilia,  these  perhaps  should  properly  be  re- 
stored to  their  place  amongst  animals,  notwithstanding  the  subsequent  ap- 
pearance of  cellulose-membrane  upon  them.  But  if  they  occur  in  the  swarm- 
cells  of  the  Confervae,  they  certainly  cease  to  be  a  characteristic  of  animal 
nature.     Thus,  if  we  are  not  yet  in  a  position  to  refer  Polytoma  with  perfect 


140  GENERAL  HISTOHY  OF  THE  INFUSORIA. 

certainty  to  its  proper  place,  there  is  decidedly  no  reason  for  excluding  it 
from  the  animal  kingdom.  We  will  not,  however,  venture  to  consider  the 
Infusoria  furnished  with  a  mouth  (Stomatoda,  Yon  Siebold)  as  formed,  like 
Polytoma,  upon  the  tj-pe  of  a  simple  cell:  for,  high  as  we  may  rate  the  ad- 
vantage accruing  to  science  from  the  comparison  of  the  Protozoa  with  simple 
cells,  difficulties  stand  in  the  way  of  its  complete  appHcation  in  the  case  of 
animals  of  such  complicated  structure  as  the  Vorticellce  for  example ;  and 
these  cannot  be  considered  as  entii^ely  done  away  with  until  the  history  of 
their  development  has  fiu^nished  proof  that  at  no  period  does  a  fusion  of 
several  cells  take  place. 

"  In  conclusion,  we  bring  together  the  results  of  the  investigation  as  shortly 
as  possible. 

"  1.  Polytoma  is  an  animal. 

^'2.  It  is  characterized  by  a  clear  investing  membrane,  which  does  not 
consist  of  cellulose ;  two  contractile  spaces  in  the  substance  of  the  body ;  a 
nucleus  with  a  nucleolus ;  two  filaments ;  and  by  the  deposition  of  layers  of 
starch-like  granules. 

^'  3.  The  starch-granules  may  become  converted  into  a  blue  or  green  co- 
louring matter. 

^'  4.  Polytoma  divides  within  the  investing  membrane  into  two,  four,  or 
eight  parts,  and  propagates  itself  in  this  manner. 

"  5.  It  passes  into  a  state  of  repose." 

These  arguments  wiU,  we  fear,  not  be  deemed  satisfactory  to  most  natu- 
ralists. That  the  investing  membrane  should  not  be  coloured  blue  by  iodine 
is  an  unimportant  fact  in  determining  its  nature  ;  for  the  same  thing  happens 
-with  many  undoubted  vegetable  tissues,  and  we  are,  besides,  not  sufficiently 
acquainted  "with  the  chemical  history  of  starch,  cellulose,  and  allied  isomeric 
substances,  to  appeal  to  their  presence  or  absence  as  decisive  of  an  animal  or 
vegetable  nature.  Then,  again,  as  to  the  contractile  spaces,  these  cannot  be 
considered  peculiar  to  animal  life,  seeing  that  they  are  present  in  such  gene- 
rally recognized  vegetable  forms  as  Chlamydomonas,  Gonimn,  and  Volvooc. 

Moreover,  Schneider  himself  describes  starch -granules  and  chlorophyll- 
vesicles  within  Polytoma,  which,  if  these  substances  had  any  decisive  bearing 
on  the  question,  would  quite  settle  its  affinity  with  plants,  irrespective  of  the 
constitution  of  the  enveloping  membrane.  Besides,  the  whole  history  of  the 
organism  accords  so  closely  with  the  known  phenomena  of  life  and  develop- 
ment of  the  simplest  plants,  that  this  alone  must  cany  much  weight  in  fixing 
its  position  in  the  scale  of  beings. 

FAMILY  II.— CRYPTOMOI^ADINA. 

(Plates  XYIII.  29—34.) 

The  Crtptomonadina,  which  follow  the  Monadina  in  the  arrangement  of 
Ehrenberg,  claim  but  a  brief  consideration,  inasmuch  as  so  little  precise  infor- 
mation is  obtainable  with  respect  to  them,  and  as  the  existence  of  possibly 
all  of  them  as  independent  organisms  is  a  matter  of  much  uncertainty.  The 
genera  enumerated  were — Cryptomonas,  Ojphkloinonas,  Urocentrum,  Lagenella, 
Cryptoglena,  and  TracJielomonas.  To  characterize  the  Cryptomonadina  in  two 
words,  they  are  encysted  Monadina  or  Eugienese.  Ehrenberg  puts  forward  the 
following  account : — ''  They  exhibit  all  the  characteristics  of  the  Monadina, 
but  have,  in  addition,  an  external  diaphanous  membrane  or  lorica,  which 
either  encloses  them  entirely—?',  e.  forms  an  urceolus, — or  leaves  one  side 
exposed,  and  so  constitutes  merely  a  shield — scutellum.  Locomotive  organs, 
in  the  shape  of  two  delicate  filiform  and  generally  retractile  filaments  or  pro- 


OF  THE  PHYTOZOA.  141 

boscides,  extend  from  the  margin  of  the  mouth  in  all  the  genera  except  Lag enella, 
in  which  also,  by  the  way,  Wemeck  thinks  he  has  discerned  them.  Coloured 
food  has  not  been  kno^ii  to  be  received  ;  and  hence  the  nutritive  organization 
has  not  been  demonstrated:  however,  in  six  or  seven  species  (nearly  one -half  the 
family)  internal  gastric  cells  have  been  discovered.  In  two  genera  sensation  is 
exhibited  by  the  presence  of  a  coloui^ed  spot  or  ocellus  at  the  fore  part  of  the 
body.    Multiphcation  by  complete  division  has  been  seen  in  some  specimens." 

Such  is  Ehrenberg's  account  of  Cryptomonadina.  Dujardin  has  a  parallel 
family  with  it  he  names  Thecamonadina,  and  details  the  following  particu- 
lars (op.  cit.  p.  323) : — "  The  Infusoria  of  this  family  having  in  some  mea- 
sure merely  one  negative  character  in  common,  viz.  the  non- contractility  of 
their  integument,  can  be  divided  into  several  families  accorchng  to  the  nature 
of  the  enclosing  membrane  and  the  number  and  disposition  of  their  locomo- 
tive filaments.  Thus,  some  are  globular  and  others  leaf- like  ;  some  have  a 
hard,  as  it  were  stony  shell,  whilst  others  are  covered  only  by  a  thin  flexible 
membrane ;  some,  again,  have  but  one  filament,  others  two  similar  ones  or 
two  of  different  size,  and  others,  again,  more  than  two.  Until  new  observa- 
tions have  augmented  the  number  and  the  knowledge  of  species,  the  diff'er- 
cnces  just  pointed  out  will  merely  serve  to  characterize  genera  which  are 
indeed  much  more  really  distinct  in  this  family  than  in  Monadina.  The 
Thecamonadina  are  in  fact  more  advanced  in  organization  than  the  Monadina ; 
they  are  not,  like  the  latter,  produced  in  artificial  infusions,  nor  do  they  change 
figure  and  characters  according  to  the  medium  in  which  they  exist.  They 
stand  in  the  same  relation  to  the  Monadina  that  the  Ehizopoda  (Arcellina,  or 
Monothalamia)  do  to  the  Amoeba; :  their  organs  are  no  more  distinct ;  but  their 
individuality  is  more  pronounced." 

'^  The  Thecamonadina  are  all  very  small,  although  they  may  be  rendered 
visible  to  the  naked  eye  by  their  accumulation  in  great  numbers,  and  by  the 
colour  they  then  give  rise  to  ;  their  colour  is  usually  green, ....  but  sometimes 
red.  They  are  mostly  cognizable  by  the  stiffness  of  their  body  and  the 
uniformity  of  their  movement."  Dujardin  ignores  the  stomach-sacs,  the  con- 
tractile seminal  vesicle,  the  testis,  and  the  green  ova  which  Ehrenberg  attri- 
buted to  this  family ;  he  likewise  can  assign  no  value  to  the  eye- specks  as 
generic  features,  and  is  compelled  to  deny  the  occiu-rence  of  shells  in  the 
form  of  a  sliield,  open  on  one  side ;  for  those  appearing  so  are  merely  flattened 
on  that  aspect.  He  adds,  the  integument  in  all  these  cases  is  much  more 
roomy  than  the  contents,  from  which  it  is  separated  by  a  clear  space  having 
the  appearance  of  a  ring. 

Perty  adopts  both  the  terms,  Cryptomonadina  and  Thecamonadina,  to  ex- 
press the  two  families  under  which  he  arranges  the  several  genera  enumerated 
by  Ehrenberg  and  Dujardin,  together  with  some  instituted  by  himself.  This 
is  not  the  place  to  point  out  the  distinctions  he  has  di^awn  between  the 
two  families  so  constructed  ;  but  the  original  observations  Perty  has  made  on 
some  specimens  will  be  of  interest.  For  instance,  he  says  that  {op.  cit.  p.  81), 
"  When  the  green  animalcule  of  Trypemonas  volvocina  (Trachelomonas  vol- 
vocina,  Ehr.)  is  about  to  self-divide,  it  contracts  itself  within  its  glass-like 
globular  shell,  oscillates  to  and  fro,  whilst  the  motor-fibres  become  lost,  or 
remain  without  fmiher  connexion  with  the  animal,  fixed  in  the  circular 
opening  of  the  outer  shell.  Eission  now  proceeds  in  the  usual  mode  into 
two  and  four  individuals,  which  on  their  completion  exhibit  the  red  stigma, 
p^e^dously  undistingmshable  among  the  green  molecules :  the  breaking  up 
of  the  sheU,  scarcely  -j-cMj_th  of  a  line  in  thickness,  is  effected  either  by 
the  movements  of  the  contained  beings  or  by  dissolution."  The  shells  of 
Trypemonas,  Chonemonas,  and  Cryptomonas,  which  contain  no  silex  in  their 


142  GENERAL  HISTORY  OF  THE  INFUSORIA. 

composition,  seem  to  be  particularly  prone  to  decomposition,  so  that  their 
empty  shells  or  their  fragments  are  extremely  seldom  to  be  met  with  in 
water  abounding  in  loricated  Monads.  "  In  Cryptomonas  pohjmorpha  I  have 
repeatedly  witnessed  this  rapid  breaking  up  of  the  shell ;  the  margin  is  resolved 
into  numerous  drops  which  separate  from  one  another,  and  in  the  course  of 
ten  or  twelve  minutes  the  lorica  spreads  itself  out  as  an  inconspicuous  mem- 
branous structure.  Moreover,  in  Chonemonas  hispkla  a  constant  movement 
is  observed  in  the  shell  when  the  animal  is  about  to  divide,  and  when,  as 
almost  always  happens,  the  filaments  are  lost,  or  remain  attached  to  the  shell 
without  any  connexion  with  the  animal.  Until  the  period  of  self-division 
the  connexion  between  the  animal  and  shell  persists,  for  the  latter  is,  at  its 
origin,  simply  the  hardened  periphery  of  the  former ;  but  when  fission  hap- 
pens this  bond  is  ruptui^ed  and  cannot  be  re-established,  and  the  contained 
animalcule,  being  thus  set  free,  no  longer  moves  ^vith  the  sheU,  but  in  it,  and 
this  in  an  uneasy,  irregular  manner."  At  p.  83  he  goes  on  to  say  that  in 
Cryptomonas  polymorpha  internal  germs  (Blastien)  are  almost  constantly 
cognizable  ;  in  smaller  and  young  specimens  in  less  abimdance.  In  a  pool 
containing  Utricular ia  in  July  1848,  he  met  with  the  dark  green  variety  in 
immense  numbers,  along  with  clear  green  germs  from  -^^"'  to  -^l^'",  col- 
lected in  masses  held  together  by  a  very  dehcate  peUicle,  and  either  motion- 
less or  in  active  movement  among  the  old  individuals.  In  other  varieties  he 
has  seen  similar  germs.  ThiLS,  on  pressing  the  large  brown  variety  the  germs 
escaped  as  independent  isolated  beings.  In  the  hyaline  variety  (ChiJomonas 
Paramecium,  Ehr.)  he  not  seldom  witnessed  astonishingly  rapid  development 
by  longitudinal  fission  ;  in  one  specimen  the  two  halves  remained  for  a  con- 
siderable time  tied  together  by  a  band,  which  became  stretched  thinner  and 
thinner  by  the  long- continued  movements  of  the  two  beings  until  it  at  length 
gave  way.  After  moving  about  for  some  time,  vital  energy  is  lost,  and  probably 
one-half  of  the  specimens  sink  to  the  bottom  of  the  di'op  of  fluid  under  obser- 
vation. The  germs  in  this  hyaline  variety  are  moreover  very  evident  and 
numerous.  Amid  the  many  specimens  of  nearly  equal  and  minute  size, 
others  much  larger  are  not  uncommon,  fiuTiished  with  a  red  eye-speck. 

Schneider  gives  (A.  N.  H.  1854,  xiv.  p.  327)  an  account  of  Chilomonas 
Paramecium,  difi'ering  much  from  the  foregoing.  He  describes  it  as  ha\dng  a 
clear  nucleus  with  a  reddish  halo  around  it,  and,  although  he  could  distin- 
guish no  contractile  space,  observed  a  reddish  vesicle  always  in  the  anterior 
extremity,  and,  in  direct  opposition  to  Forty's  observations,  states  that  what- 
ever number  of  these  animals  he  examined,  he  never  observed  multiplication 
by  fission  (p.  133). 

In  March  1848,  Perty  noticed  Anisonema  acinus  (Duj.)  in  different  stages  of 
development ;  the  smallest  forms  were  evidently  derived  from  the  germs,  about 
J^'"  in  length,  and  circular ;  by  further  growth  they  became  elliptic,  and 
presented  a  larger  number  of  internal  germs  ;  at  the  same  time  the  fibres, 
which  are  so  easily  seen  in  the  fuU-gro^Ti  beings,  were  perceived  with  the 
greatest  difficulty  in  the  smallest. 

Among  his  Thecamonadina  are  enumerated  two  genera,  named  Chonemonas 
and  Trijpemonas :  the  latter  is  equivalent  to  Ehrenberg's  genus  Traclielo- 
monas ;  but  the  former  includes,  besides  Lagenella,  two  genera  which  the 
Berlin  systematist  placed  in  families  far  removed  from  his  Ciyptomonadina, 
viz.  CJicetoglena,  placed  among  the  Peridinicea,  and  Pantotrichum ,  classed  with 
the  Cyclidina.  Concerning  the  reproduction  of  these  two  genera,  Perty  has 
some  original  observations. 

In  some  decomposing  water  he  met  with  Chonemonas  and  Trypemonas  in 
great  abundance— the  greater  part  of  a  green  colour  with  red  eye-specks. 


OF  THE  PHYTOZOA. 


143 


without  lorica,  and  of  various  dimensions.  In  both,  the  lorica  fii'st  made  its 
appearance  as  a  smooth  hyaline  envelope,  which  grew  stronger,  then  red,  and 
at  length  brown  or  blackish  brown — becoming  also  in  CJwnemonas  still  firmer, 
and  covered  with  asperities.  Duiing  this  transition  from  a  soft  peripheiy  into 
a  shell,  two  sets  of  intersecting  lines  were  at  times  visible,  which  by-and-by 
vanished.  Moreover,  examples  of  Clionemonas  occurred  which  continued 
smooth,  and  constituted  the  variety  Ch.  glabra.  By  using  very  high  mag- 
nifying powers  to  fully  developed  specimens  of  Trypemonas  volvocina,  the 
lorica  appeared  to  be  everywhere  perforated,  or  more  probably  beset  with  a 
series  of  depressions  or  thinner  spots.  On  the  shell  becoming  very  dark,  the 
green  contents  and  the  red  stigma  ceased  nearly  or  quite  to  be  visible.  jS"aked 
Chonemonads  and  Trypemonads  are  easily  distinguishable  from  EugUnoi, 
because  theii*  contractihty  is  so  much  less,  and  consequentlj^  their  actual  round 
form  so  much  the  more  permanent.  All  these  minute  naked  examples  are 
doubtless  produced  from  germs  :  fission  was  witnessed  in  no  instance.  Ordi- 
narily the  animal-Hke  Chonemonas,  furnished  with  a  red  eye-speck,  had  an 
elliptical  form  prior  to  the  construction  of  the  shell,  just  hke  loricated  forms  ; 
yet  ovate  and  obovate  examples  are  also  to  be  seen.  Minute  specimens  are 
poorer  in  endochrome,  this  material  occurring  only  in  one  or  two  specks.  The 
locomotive  filaments  are  absent  at  first,  and  after  their  appearance  only  gra- 
dually attain  the  normal  length.  The  construction  of  the  lorica  frequently 
proceeds  to  completion  in  very  small  specimens,  whilst  large  ones  remain 
naked,  notwithstanding  the  formation  of  germs  goes  on  in  those  where  the 
chromule  is  in  a  certain  quantity.  Many  dead  Chonemonads  were  encountered 
having  theii'  contents  either  sliiivelled  up  or  even  so  completely  removed  as 
to  leave  only  an  empty  yellowish-brown  shell. 

At  a  subsequent  page  (p.  131)  Perty  mentions  certain  abnormal  forms, 
among  others  Cryjotomonas  polymorpha,  having  but  one  instead  of  two  fila- 
ments, and  at  other  times  elongated  into  a  tail-like  process. 

From  all  the  preceding  accounts  of  Cryptomonadina  there  seems  sufficient 
to  show  that  these  beings  are  but  a  certain  phase,  the  encysted  state,  of  a 
set  of  organisms  which  have  a  general  resemblance  to  zoospores,  or  to  simple 
unicellular  Algce.  The  germs  mentioned  by  Perty  accord,  to  all  appearance, 
with  the  microgonidia  of  other  authors,  and  behave  themselves  in  a  similar 
manner.  Cohn  observes  {A.  N.  H.  1852,  x.  p.  335) — "  Trachelomonas  and 
the  analogous  forms  do  not  belong  to  the  vegetable  kingdom  at  all,  but  are 
nearest  alhed  to  the  Astasisea,  and  appear  to  be  loricated  Euglenese,  not 
loricated  Monads,  as  Ehrenberg  assumed."  AYe  shall  hereafter  see  that  this 
indefatigable  naturalist  leans  to  the  behef  that  Eugleneae  are  animals  ;  hence 
the  idea  he  puts  forward  respecting  the  Trachelomonads. 

As  these  sheets  were  passing  through  the  press,  Mr.  Carter's  valuable 
paper  on  Eudorina  and  Cryptoglena  made  its  appearance  {A.  N.  H.  1858,  ii. 
p.  237).  The  Cryptoglena  described  is  supposed  to  be  a  new  species,  and  is 
named  C.  lentkularis,  on  account  of  its  lenticular  shape.  It  is  compressed 
and  emarginate,  and  furnished  with  a  pair  of  cilia.  In  this  little  being 
Mr.  Carter  supposes  an  act  of  fecimdation  to  take  place,  the  microgonidia 
being  supposed  to  represent  the  male,  the  macrogonidia  the  female  element. 
Among  the  numerous  specimens  met  with,  there  was  a  nimiber  of  deciduous 
lorica,  *'  some  of  which  were  split  into  halves  which  were  separated,  while 
others  only  adhered  together  anteriorly,  and  presented  a  pair  of  ciHa  attached 
to  their  point  of  union."  In  several  instances,  the  internal  cell,  or  the  con- 
tents enclosed  in  their  protoplasmic  sac,  often  distended  by  imbibition  of  water 
to  three  or  four  times  the  dimensions  of  the  germ  lorica,  were  seen  escaping 
from  the  separated  segments  of  the  latter,  and  in  their  globular  shape  and 


144  GENERAL  HISTORY  OF  THE  INFUSORIA. 

general  features  undistinguishable  from  Chlamydococcus  under  similar  forms. 
These  escaping  internal  cells  were  divided  into  two,  four,  eight,  and  sixteen 
parts  ;  and  it  was  noticed  that  the  variety  which  came  forth  with  only  two 
gonidia  was  surrounded  by  a  swarm  of  from  ten  to  twenty  much  smaller 
gonidia,  which  were  identical  in  all  appearance  with  those  resulting  from 
di\dsion  into  sixty-four  parts.  But  the  cells  divided  into  two  segments  were 
not  the  only  ones  so  surrounded  by  microgonidia ;  for  in  two  or  three  instances 
a  few  were  found  around  and  adhering  to  the  inner  cell  of  those  divided  into 
four  gonidia. 

''  It  was  also  observed  that  the  two-division  did  not  always  come  forth  in 
one  cell,  but  that  sometimes  this  was  also  divided,  so  that  each  gonidium  had 
its  proper  cell.  The  foiTU  of  the  macrogonidia  or  female  cells  did  not  differ 
from  the  internal  cell  of  the  parent,  except  in  being  a  httle  smaller, — while 
the  microgonidium,  which  was  not  more  than  l-7th  of  the  diameter  of  the 
macrogonidium,  and  therefore  very  small,  appeared,  though  equally  green,  and 
provided  with  an  eye-spot,  to  have  only  one  cilium.  I  cannot  help  thinking, 
however,  that,  with  a  higher  power,  I  might  have  seen  two." 

The  purpose  fulfilled  by  the  contact  of  the  microgonidia  with  the  macro- 
gonidia, Mr.  Carter  concludes  to  be  that  of  impregnation ;  for  he  observed 
one  of  the  former,  as  a  spermatozoid,  fix  itself  to  one  of  the  latter  (the  spores 
or  female  cells),  and  gradually  become  incorporated  with  it.  The  microgo- 
nidium, after  having  so  attached  itself,  assumed  a  conical  or  peg-top  shape, 
and  thus  appeared  to  gradually  squeeze  itself  into  the  macrogonidium. 

This  mode  of  impregnation,  thus  directly  observed  by  Mr.  Carter,  is  the 
copy  of  that  the  same  observer  witnessed  in  Eudorina  (Pcmdorina),  and  of 
that  first  noted  by  Cohn  in  Volvo a\  He,  moreover,  believes  that  it  obtains 
in  the  case  of  Trachelomoiuis,  for  he  '^  has  often  seen  the  largest  Trachelo- 
monad  of  a  pool  divided  up  into  a  group  of  apparently  sixteen  cells  within 
the  lorica ;  and  this  may  account  for  the  myriads  of  three  to  four  smaller 
sizes  that  are  frequently  found  together  in  this  way.  The  latter  certainly 
appear  in  a  green  form  first ;  that  is,  without  the  lorica,  which  gradually 
becomes  supplied  afterwards.  Thus,  impregnation  also  in  the  Trachelomo- 
nads  may  take  place  like  that  seen  in  Eudorina,  after  the  parent-cell  has 
undergone  division  within  the  lorica."  (See  Part  II.,  Systematic  History  of 
Cryptomonadina. ) 

FAMILY  III.— YOLVOCTNE^  OR  YOLYOCINA. 
(Plates  XIX.  XX.) 

This  is  the  most  important  and  most  interesting  family  of  the  Phytozoa. 
The  genera  enumerated  in  it  by  Ehrenberg  were  Gyges,  Pandorina,  Go- 
nium,  Syncrypta,  Synura,  Uroglena,  Eudorina,  Chlamydomonas,  Sphwrosira, 
and  VoJvox,  The  name  is  derived  from  the  rolling  (volvere,  to  turn)  motion 
of  the  genus  Volvox,  which  is  typical  of  the  family.  Ehrenberg  was  the 
first  rightly  to  appreciate  the  tme  nature  and  compound  structure  of  the 
principal  genera  as  the  aggregation  of  numerous  monadiform  beings  in  a 
common  polypary-like  mass.  He  correctly  described  the  several  individuals 
as  resembhng  Monads  in  most  particulars  of  their  organization,  but  was  so 
carried  away  beyond  this  simple  natural  statement  by  his  pecuhar  views  of 
structure,  as  to  describe  them  as  having  an  unvarying  body,  without  other 
external  appendages  than  a  pair  of  cilia  or  filaments,  and  internally  several 
digestive  sacs  but  no  true  alimentary  canal,  green  ova,  two  rounded  seminal 
glands,  a  contractile  (spermatic)  vesicle,  and  eye-specks  indicating  the  exist- 
ence of  sensation.      The   substance  connecting  the   several  beings,  and  in 


OF  THE  PHYTOZOA.  145 

which  they  arc  imbedded,  he  called  the  lorica,  and  stated  that  propagation 
occurred  by  self-di\'ision  within  the  envelope,  and  probably  also  by  ova. 

The  genera  Chlamydomonas  and  Gyges,  or  Cldamydococcus  (XIX.  9-31), 
offer  an  exception  to  the  other  members  of  the  family  in  not  producing 
aggregate  forms  or  colonies,  at  least  not  in  their  assumed  typical  phase. 

A\Tiilst  denying  in  toto  the  elaborate  animal  organization  presumed  by 
Ehrenberg,  M.  Dujardin  nevertheless  continued  to  recognize  the  Volvocina 
as  animal  structures,  and  contented  himself  with  merely  proposing  a  dif- 
ferent distribution  of  the  genera.  However,  since  this  distinguished  French 
naturalist  wrote,  the  opinion  has  been  powerfully  advocated,  and  everywhere 
gaining  ground,  that  the  Volvociaece  belong  to  the  vegetable  kingdom ;  con- 
sequently their  structiu'e  and  \dtal  phenomena  receive  quite  a  different  inter- 
pretation from  that  given  by  the  writers  above  named. 

The  Vohocineoi  are  now,  in  the  language  of  algologists,  '  Tetraspora,''  of 
the  family  Palmelhce  or  PalmeUacece.  The  monadiform  beings  are  '  primor- 
dial cells,'  and,  in  more  general  language,  '  corpuscles,'  whilst  the  common 
pellicle  or  nidus  connecting  them  is  called  by  Cohn  and  others  the  '  envelope- 
cell.'  The  author  just  named  says  {Enhv.  p.  165),  that,  from  his  observa- 
tions on  Cldamydococcus,  Chlamydomonas,  and  Stephanosphcpra,  the  Volvo- 
cinece  in  general  consist  essentially  of  two  parts  : — 1.  of  a  colourless,  hyaline, 
completely  closed,  and  usually  spherical  envelope-cell  composed  of  cellulose ; 
and  2.  of  green  2)rimordial  cells,  single  in  the  two  first-named  genera,  but 
eight  in  number  in  Steplianosphoira,  enclosed  within  the  envelope -cell.  In 
each  case  these  cells  are  simply  primordial  sacs,  unenclosed  by  any  special 
firm  cellulose  membrane,  and  consist  of  a  fine  granular  protoplasm,  coloiu'ed 
green  or  red  by  clilorophyll,  or  by  a  peculiar  oil  (XIX.  48,  49).  The  proto- 
plasm forms  only  the  outer  layer  of  the  ceUs,  and  is  often  prolonged  on  the 
inner  siu-face  of  the  '  envelope-cell '  in  the  form  of  delicate  mucous  fibres 
(XIX.  53).  The  primordial  cells  are  moreover  themselves  elongated  from 
before  backwards,  forming  a  colourless  apex  from  which  two  vibratile  fila- 
ments take  their  rise,  and  passing  through  two  foramina  in  the  envelope- 
cell,  stretch  themselves  outwards  in  the  siuTounding  water,  and  by  their 
vibration  serve  to  move  the  entire  compound  organism.  The  only  difference 
between  ChJamydococcus  and  Stephayiosplicera  is  one  affecting  the  mode  of 
development,  in  which  only  the  primordial  cells  (not  in  any  way  the  common 
envelope)  take  part.  These  cells  divide  first  into  two,  then  into  four,  then 
into  eight  or  more  daughter- cells  (macrogonidia)  (XIX.  40,  41,  42) ;  but 
after  the  third  or  the  second,  and  often,  indeed,  after  the  first  act  of  division, 
a  permanent  generation  results.  Thus,  in  Chlamydomonas  and  Chlamydo- 
coccus,  each  of  the  daughter- cells  becomes  free  and  independent,  encloses 
itself  within  an  envelope-cell  of  its  own,  and  after  developing  two  fibres, 
breaks  through,  mth  their  aid,  the  common  envelope  of  the  parent-cell  (XIX. 
23-26  and  30).  In  Stephanospha=ra,  on  the  contrary,  the  eight  primordial 
cells  produced  hj  the  third  act  of  fission  secrete  around  themselves  a  common 
envelope  (XIX.  c>Q),  which  invests  them  like  an  integument,  first  Ipng  close 
upon  them,  but  afterwards,  through  the  imbibition  of  water,  raised  from 
them  all  round,  assuming  a  globular  fonn ;  but  so  that  the  primordial  cells 
occupy  the  periphery  at  the  equator  of  the  globe  like  a  ring  or  zone  (XIX, 
57,  58),  having  their  eight  pairs  of  filaments  protruded  through  the  openings 
in  the  common  envelope  (XIX.  38).  ChJamydococcus  and  Chlamydomonas 
stand  in  the  same  relation  to  Stephanosphcera  that  Pleurococcus  does  to  Pal- 
mell-a,  Phycastnim  to  Desmidium,  Navicula  to  Schizonema,  VorticeVa  to  Epi- 
stylis,  or  as  Hydra  to  Campanularia. 

But,  further,  a  second  mode  of  development,  \^z.  by  microgonidia,  prevails 


146  GENERAL  HISTORY  OF  THE  INFUSORIA. 

alike  in  the  three  genera  in  question,  the  bisection  of  the  contents  of  the 
cell  proceeding  so  far  that  they  are  eventually  resolved  into  numberless  small, 
mostly  spindle-shaped  corpuscles  (XIX.  51),  which  at  first  oscillate  by  the 
aid  of  two  or  four  \ibratile  filaments  mthin  the  common  envelope-cell,  but 
subsequently  escape  singly  from  it,  (XIX.  52),  and,  after  enjoying  for  a  con- 
siderable time  very  energetic  infusorial  movements,  finally  pass  into  a  state 
of  rest,  preparatory  to  some  futui'e  development. 

"  The  larger  undivided  macrogonidia,  after  swarming  often  the  whole  day, 
are  also  seen  to  enter  (as  ^vitnessed  in  Chlami/dococcus  and  Steplianosphcera) 
into  the  condition  of  rest,  when  each  primordial  cell  contained  within  the 
delicate  envelope-cell  secretes  about  itself  a  second  more  compact  cellulose 
membrane  which  closely  invests  it,  and  is  not  perforated  by  the  ciliary  fila- 
ments (XIX.  20,  21).  It  is,  in  fact,  the  countei^part  of  the  membrane  which, 
in  common  plant-cells,  overhes  the  primordial  layer.  In  tliis  distinctly 
plant-like  or  protococcoid  condition  the  cells  remain  without  motion,  and 
may  endure,  even  when  dried,  for  a  whole  year,  and  then,  on  the  addition  of 
water,  undergo  segmentation  into  two,  foui',  or  eight  gonidia,  which,  imme- 
diately after  developing  their  filaments  and  envelope-cells,  break  through  the 
walls  of  the  parent -cell  and  crowd  the  surrounding  fluid." 

The  facts  relating  to  the  structure  and  functions  of  the  genera  above 
adduced,  apply  in  the  main  to  all  the  Volvocinece ;  for  the  diff'erences  between 
the  several  genera,  although  demanding  special  consideration,  are  not  essen- 
tial. Thus,  for  example,  in  Gonium  (XIX.  32)  the  figiu'e  is  a  flattened  sphe- 
roid, and  the  green  primordial  cells,  \iewed  collectively  fi'om  above,  resemble 
a  four- sided  disc  or  plate,  having  each  angle  truncated.  Moreover,  the  trans- 
parent coloiu'less  envelope  does  not  acquire  the  character  and  appearance  of 
a  firm  membrane,  but  presents  itself  as  a  mucous  or  gelatinous,  not  cellulose, 
sheath. 

Chlamydomonas. — The  first  of  the  genera  included  by  Ehrenberg  in  his 
family  Vohocina,  of  which  we  shaU  attempt  a  description,  is  Chlamidomonas 
or  Chlamydomonas  (XIX.  16).  It  recommends  itseK  to  our  attention  because 
of  its  simplicity  and  its  existence  in  an  isolated  state.  This  last  fact  seemed 
to  Dujardin  a  sufiicient  reason  for  remo^dng  it  from  the  Volvocina  to  the 
Thecamonadina,  and  for  renaming  it  Disehnis,  on  accoimt  of  its  having  two 
filaments ;  for  he  would  admit  into  the  former  family  only  aggregate  organ- 
isms "  enclosed  within  a  common  envelope,  or  ha\'ing  special  envelopes 
mutually  adherent."  On  this  same  ground  he  also  advocated  the  transposi- 
tion of  Gyges  from  the  Volvo.v  family  to  that  of  the  Thecamonadina,  a  genus 
which  we  shall  presently  have  to  note  under  the  name  of  Chlamydococcus  or 
Profococcus  pluviaVis.  To  this  arrangement  Cohn  objects  {A.  N.  H.  1852, 
X.  p.  334) ;  for,  says  he,  ''  a  more  profound  investigation,  not  only  of  the 
structure,  but  also  of  the  history  of  development,  teaches  us  that  Chlamydo- 
monas (Disehnis,  Duj.)  possesses  only  external  analogies  with  Trachelomonas, 
while  this  form,  as  Ehrenberg  abeady  discovered,  exhibits  the  closest  alhance 
to  Gonium  and  Pandorina.  The  relation  of  the  colourless  envelope  to  the 
enclosed  green  globes,  the  position  of  the  two  ciha,  which  arise  from  the  latter 
and  pass  out  through  the  former,  and  lastly,  the  laws  of  division  of  the  green 
cells  inside  the  envelope,  in  powers  of  two,  display  themselves  in  exactly  the 
same  way  in  Chlamydococcus  as  in  the  rest  of  the  Volvocinece ;  and  the  only 
distinction  between  them  consists  in  the  circumstance  that  in  Chlamydomonas 
(and  Chlamydococcus)  the  individuals  produced  by  the  di\-ision  of  the  green 
globes  separate  after  the  absorption  of  the  parent  envelope,  and  live  on  as 
individuals,  while  in  the  other  Volvocineoi  the  daughter- cells  produced  by 
the  division  of  one  green  primordial  cell  remain  connected  by  the  persistent 


OF  THE  PHTTOZOA.  147 

parent- cell  as  by  a  common  envelope,  and  move  about  as  a  well-defined  body 
composed  of  many  cells." 

The  best  accounts  of  the  structm^e  of  Chlamydomonas  we  have  at  hand  are 
those  by  Perty  (op.  cit.  p.  85),  by  Eraim  (Eejiiv.,  li.  S.  p.  214),  and  by 
Thuret  (Sw  les  Zoospores,  Ann.  Sc.  Nat.  xiv.  1850).  Unfortunately,  each 
of  these  writers  describes  a  different  species,  which  renders  our  attempt  at  a 
general  history  the  more  difficult.  The  figure  varies  between  ovoid  and 
globular ;  and  the  cell  is  not  prolonged  at  the  point  from  which  the  pair  of 
vibratile  filaments  proceed,  although  a  colourless  space  exists  there.  The 
organism  consists  of  a  green  mass — the  primordial  cell — surrounded  by  a  dia- 
phanous delicate  envelope,  wliich,  unlike  that  of  Chlamydococciis,  is  closely 
applied  to  it,  so  that  it  leaves  no  clear  interspace  between  the  two.  The 
contents  are  green  globules  and  larger  vesicles,  ^ith  a  single  large  chlorophyll- 
utricle  in  the  centre — the  nucleus  (XIX.  16) — very  like  in  appearance  to  the 
starch-globule  so  frequent  in  the  cells  of  green  Algae.  In  addition,  there  is 
a  red  stigma,  and  in  some  rare  instances  two  such ;  in  other  examples,  again, 
it  is  altogether  wanting.  Motion  is  effected  by  the  ciliaiy  filaments,  which 
penetrate  the  external  envelope  from  the  enclosed  globule;  the  envelope 
resembles  that  of  zoospores  in  general ;  and,  like  those  structures,  these  uni- 
cellular beings  seek  the  light  and  exhale  oxygen. 

Perty  describes  colourless  germs  from  which  new  specimens  originate, — a 
statement  no  doubt  equivalent  to  saying  that  these  beings  reproduce  them- 
selves by  microgonidia,  as  Cohn  represents.  Fission  into  macrogonidia  is 
binaiy  or  quaternary,  as  in  Tetnispora,  and  gives  rise  to  two,  fom%  eight,  and 
even,  at  times,  sixteen  or  thirty- two  individuals.  Generally  whilst  this  act 
proceeds  the  cells  are  quiescent,  ceasing  from  their  usual  movements.  This 
process  of  multiplication  is  not  influenced  by  the  size  of  the  Chlamydomonads, 
for  it  occurs  in  specimens  varying  between  -j^  to  -^-j'". 

Amid  the  film-like  collections  of  Chlamydomonas,  groups  of  individuals  may 
be  encoimtered  in  various  stages  of  change  and  of  breaking  up :  some  have 
entirely  or  partially  lost  their  green  contents ;  others  have  acquired  a  yel- 
lo'\\'ish-brown,  or,  more  seldom,  a  red  colour ;  others  are  much  contracted  as 
small  globules  within  the  clear  gelatinous  cases,  whilst  others,  lastly,  acquire 
a  proboscis-like  process,  or,  by  pressiu'e,  an  angular  outline. 

The  variety  and  transition  of  colour  just  remarked  depend  upon  the  phase 
of  existence  and  the  entrance  on  the  resting  or  quiescent  condition.  The 
ceUs  of  Cldamydomonas  ohtusa,  Braun  teUs  us,  when  swarming  are  of  a  dark 
green  coloui',  truncate  at  both  ends,  and,  after  multiplying  for  some  time, 
produce  here  and  there  veiy  minute  paler  and  more  bro^vnish-yeUow  micro- 
gonidia. "  In  the  course  of  a  few  weeks  no  more  active  cells  could  be  found 
in  the  water,  the  full-gro^Ti  swarms  having  all  gradually  come  to  rest  and 
sunk  to  the  bottom.  The  original  longish  shape  of  the  cells  had  changed 
into  a  perfect  sphere  with  the  transition  to  rest ;  the  colour  of  these  resting- 
cells,  origmally  green,  gradually  passed  into  a  light  yellowish  brown ;  at  the 
same  time  a  number  of  small,  sharply- defined,  brilliant  globules  were  formed 
in  the  interior,  ha\TLig  quite  the  appearance  of  drops  of  oil.  In  this  altered 
condition  the  Chlamydomonads  remained,  exhibiting  neither  growth  nor 
increase."  It  is  added,  in  a  note,  that  these  resting  (seed)  cells  are  about 
■^"'  in  diameter,  have  a  tough,  colourless,  and  transparent  membrane,  and 
finally  assume  a  flesh-red  coloiu-.  On  awakening  from  this  '  resting  '-stage, 
segmentation  of  the  contents  re^ives,  with  the  disappearance  of  the  red  and 
oil-like  elements.  The  resting-stage  of  the  microgonidia  has  not  been  suffi- 
ciently investigated, 

Chlamydomonas  Pidvisadus.  in  the  opinion  of  Cohn  and  most  others,  is 

l2 


148  GE^^ERAL  mSTOEY  OF  THE  IXFrSORIA. 

undistiiigiiishable  from  Pohjtoma  UvelJa  in  every  material  i3oint, — the  absence 
of  colour,  and  its  habitat  in  decomposing  infusion  alone  offering  themselves 
as  distinctive  of  the  latter.  Nay,  what  is  more,  he  discovers  the  intimate 
resemblance  of  Ghlamydomonas  to  the  resting- stage  of  a  Volvooc  which  he 
discovered  in  decomposing  infusions,  and  named  V.  liyalma.  From  these 
considerations  he  concludes  that  Clilamydomonas  and  Polytoma  must  be  ranked 
with  Volvox  in  the  vegetable  kingdom. 

But  ChJamydomonas  is  made  to  appear  a  metamorphic  condition  of  yet 
other  organisms.  For  instance,  Itzigsohn  states  that,  after  the  joints  of  the 
filaments  of  Oscillaria  tenuis  are  separated,  they  produce  motile  gonidia 
"  Avhich  present  in  all  respects  the  aspect  of  Chlamydomonads,  but  which, 
after  passing  through  many  intermediate  forms,  grow  into  perfect  Euglence. " 
(J.  M.  S.  1854,  p.  189).  Likewise  Hartig,  in  his  account  of  the  transforma- 
tions of  the  Phytozoa  of  Antheridia  (J.  M.  S.  1855,  p.  54),  makes  one  phase  to 
resemble  Chlamydomonas  destruens  of  Ehrenberg.  Lastly,  Cohn  confesses 
{On  Protococmis,  R.  S.  p.  555)  that  the  motile  or  swarming  form  oi Protococcus 
is  scarcely  distinguishable  from  Chlamydomonas,  except  that  the  latter  has 
not  been  observed  by  him  in  the  '  still''  condition.  But  this  presumed  point 
of  divergence  itself  vanishes  since  Braun's  observations  have  made  us  ac- 
quainted with  the  quiescent  phase  of  that  organism  (p.  147). 

The  relation  of  Cldamydomonas  to  Stephanosphcera,  and,  in  general,  its 
alliance  with  the  Volvocina  as  a  plant,  have  been  re\dewed  in  the  preceding 
remarks  on  the  family  (p.  145). 

Chlamydococcus  (XIX.  20-31),  another  unicellular,  isolated  organism  of 
the  family  Volvocina,  has  arrested  much  attention,  and  been  described  at 
large  by  Flotow,  Braun,  Cohn,  Perty,  and  others  under  the  additional  names 
of  Protococcus,  Ha^matococms,  and  Hysginum.  Ehrenberg  has  no  genus 
similarly  named;  but  modern  researches  show  that  Gyges  is  in  part  its 
equivalent,  although  but  one  phase  of  its  existence. 

Ehrenberg's  account  of  Gyyes  is  very  meagre.  He  characterizes  it  as 
wanting  both  filaments,  eye,  and  tail,  and  as  completely  encased  within  its 
lorica  (an  urceolus).  He  could  discern  no  traces  of  a  nutritive  system,  and, 
except  a  very  slight  movement  rendered  e\ddent  by  colouring  the  fluid, 
could  detect  no  indication  of  animality.  On  the  other  hand,  Mr.  Shuttle- 
worth  examined  G.  sayiguineus,  and  stated  it  to  have  a  lively  motion  (Edinb. 
Phil.  Journ.  v.  p.  29). 

In  our  preliminary  notes  on  the  Volvocinece  in  general,  a  vegetable  nature 
is  assigned  to  the  Chlamydococcns  ;  and  its  relation  to  other  Volvocinece  is 
thus  laid  down  by  Cohn  (A.N.H.  1852,  x.  p.  335)  :^ 

"  Chlamydococcus  is  a  unicellular  Alga  in  the  strictest  sense  of  the  word, 
never  composed  of  more  than  one  cell  at  any  period  of  its  growth,  and  each 
division  forms  the  commencement  of  a  new  individual,  whilst  the  remainder 
of  the  Volvocinece  [i.e.  excepting  Chlamydomonas']  present  themselves  as 
families  of  cells,  in  which  a  definite  number  of  equivalent  ceUs  are  combined, 
in  some  measure,  into  an  individual  of  a  higher  order. 

"  The  researches  of  Alex.  Braun,  like  my  own,"  he  continues,  ''  have 
proved  most  distinctly  that  Chlamydococcus  can  only  be  placed  with  pro- 
priety among  the  Alga).  It  is  distinguished,  indeed,  from  the  moving  germ- 
ceUs  by  which  far  the  greater  part  of  the  species  of  Algse  are  propagated,  both 
by  a  somewhat  more  complex  structui'e  and  by  the  circumstance  that  the 
motion  lasts  for  a  very  long  time,  and,  finally,  by  the  power  of  the  moving 
cells  to  propagate  as  such  Avithout  entering  into  the  state  of  rest  (germina- 
tion) otherwise  than  as  quite  a  temporary  condition.  But  these  objections 
touch  only,  to  some  extent,  the  specific  character  of  Chlamydococcus  and  the 


OF  THE  PHYTOZOA.  149 

Volvociticce  generally  as  unicellular  plants;  and  they  do  not  stand  there 
among  the  Algae  altogether  without  intermediate  conditions,  as  Alex.  Braiin 
has  proved,  especially  from  the  long  movement  of  the  Volvocinece. 

"  On  the  other  hand,  the  external  form,  like  the  chemical  and  morphological 
organization  of  the  contents,  the  laws  of  motion,  and  the  general  physiological 
phenomena,  especially  however  the  behaviour  in  the  transition  into  the  con- 
dition of  rest,  in  Chlamydococcus,  agree  so  perfectly  mtli  the  moving  spores, 
the  transformation  of  which  into  undoubted  plants  has  been  demonstrated 
with  scientific  clearness,  that  no  unprejudiced  observer  can  discover  an 
essential  distinction.  I  have  mentioned  in  my  essay  that  Ehrenberg  himself, 
although  he  claims  the  moving  condition  of  the  forms  allied  to  Chlamydo- 
coccus as  Infusoria,  has  declared  the  resting-stage  of  this,  or  a  most  closely 
allied  genus,  to  be  an  undoubted  Alya ;  and  yet  the  mo\'ing  Infusoria  are 
only  a  propagative  form  of  the  motionless  Alga.  Finally,  I  have  succeeded 
in  demonstrating  the  membrane  of  the  cells  of  Chlamydococcus,  both  in  the 
resting  and  ixirticularly  in  the  moving  stage,  to  consist  of  cellulose,  and  thus 
in  establishing  the  most  important  criterion  of  a  vegetable  cell  we  are  at 
present  acquainted  with — the  ternary  composition  of  the  cell-membrane — 
in  the  Infusorioid  condition  of  Chlamydococcus.  In  fact,  all  the  more  recent 
observers  of  Chlamydococcus,  the  number  of  whom  is  not  inconsiderable, 
have,  almost  without  exception,  agreed  in  recognizing  in  all  coyiditions  of  the 
development  of  this  form,  only  a  plant  and  nothing  hut  a  plant. ^^ 

Besides  the  valuable  sketch  referred  to,  of  the  relations  of  Chlamydococcus, 
Cohn  has  presented  an  elaborate  memoir  on  this  organism  under  the  name  of 
Protococcus,  in  a  paper  translated  for  the  Ray  Society  (Botanical  and  Physio- 
logical Memoirs,  1853),  and  has  subsequently  extended  his  \iews  of  it  and 
its  aiSnities  in  his  essay  on  the  development  of  microscopical  Algce  (EntwicJc. 
d.  mihr.  Algen,  1854).  Of  these  most  important  j)apers  we  shall  make  free 
use  in  sketching  the  history  of  this  genus. 

"  The  moving  cell  of  Chlamydococcus  is  composed  of  two  principal  parts,  a 
hyaline  spherical  envelope,  which  is  formed  of  a  delicate  structureless  mem- 
brane consisting  of  cellulose,  and  immediately  surrounds  colourless  contents, 
perhaps  consisting  of  pure  water.  In  the  centre  of  the  envelope  occurs  a 
coloured  globule,  composed  of  the  universal  nitrogenous  p>7'otoplasm  or  mucus 
of  vegetable  cells,  coloiu-ed  red  or  green  by  chlorophyll  or  a  carmine-red  oil, 
and  containing  imbedded  in  it  numerous  gramdes  of  protoplasm,  as  well  as 
one  or  more  large  chlorophyll- vesicles.  This  coloiu^ed  globule  is  attenuated 
at  the  upper  end  into  a  colomdess  point ;  from  this  go  out  two  cilia,  which 
protrude  into  the  water  through  two  orifices  in  the  membrane  of  the  enve- 
lope, and  produce  the  movements  of  the  whole.  The  inner  coloured  globule 
is  not  bounded  by  any  rigid  membrane,  but  merely  by  a  thickened  layer  of 
protoplasm  ;  hence  its  contour  is  very  changeable  and  passes  through  mani- 
fold transformations  in  the  course  of  its  development.  In  particular  it  fre- 
quently becomes  elongated  in  all  directions  into  colourless  radiating  filaments, 
which  keep  the  internal  coloured  globule  suspended  freely  in  the  envelope, 
and  are  afterwards  retracted  in  the  course  of  the  development. 

''  The  motionless  cells  of  Chlamydococcus  are  of  much  simpler  structure, 
and,  like  all  forms  of  Protococcus,  consist  simply  of  a  tough  spherical  ceUiilose 
membrane  and  green  or  red  contents  organized  as  primordial  utricle.  The 
history  of  development  shows  that  under  certain  conditions  the  contents  of 
the  motionless  cells  become  divided  into  a  number  of  portions,  which  always 
correspond  to  two,  or  a  power  of  two,  in  their  number,  that  these  portions 
become  organized  into  special  primordial  utricles,  and  as  such  break  through 
the  parent-cell,  each  developing  two  cilia,  and  by  the  aid  of  these  rotating 


150  GENERAL  HISTORY  OF  THE  INFrSORIA. 

actively  in  the  water.  During  their  motion  they  excrete  a  delicate  cellular 
membrane  o\X'r  their  entire  surface,  which  is  gradually  removed  farther  and 
farther  from  the  primordial  utricle  by  endosmose  of  water,  imtil  at  length  it 
becomes  the  vnde  envelope  of  the  mo^dng  form  described  above.  From  this 
it  follows  that  the  latter  forms  do  indeed  possess  on  the  whole  the  character 
of  simple  cells,  but  display  some  peculiarities  in  theii'  stractm^e  and  develop- 
ment, since  the  internal  coloured  globule  corresponds  originally  to  the  pri- 
mordial utricle  of  other  vegetable  cells,  yet  is  not  surroimded  by  a  membrane, 
as  usual,  but  suspended  free  in  it  like  a  ceU-nucleus,  while  watery,  unazotized 
contents  appear  between  the  membrane  and  the  primordial  utricle.  For  this 
reason  I  have  called  the  enclosed  coloured  globule,  which  is  formed  first,  and 
originally  moves  about  without  a  special  membrane  in  the  manner  of  a  cell, 
and  corresponds  to  the  primordial  utricle  of  vegetable  cells  in  general,  the 
j^rimordial  cell,  and  the  enclosing  membrane  "^ith  its  watery  contents  the 
envelope-cell.  The  moving  Chlamiidococcus-QOTidiitioii  is  capable  of  propagating 
as  such,  by  the  enclosed  primordial  cell  dividing  anew,  the  individual  portions 
slipping  out  of  their  envelope-ceU  and  running  through  the  cycle  of  develop- 
ment of  their  parent-cells.  In  passing  into  the  state  of  rest,  the  enclosed 
primordial  cell  secretes  over  its  surface,  inside  its.  envelope,  like  every  pri- 
mordial utricle,  a  new  tough  cellulose  membrane,  and  through  this  metamor- 
phosis assumes  the  form  of  an  ordinary  Protococcus-cell,  while  the  envelope- 
ceU  is  dissolved.  ^  But  only  such  primordial  cells  behave  in  this  way  as  are 
produced  by  the  division  of  a  Chlannjclococcus-glohule  in  a  lower  power  of 
two :  the  primordial  cells  originating  from  a  16-64-fold  division  move  far 
more  actively  and  do  not  secrete  an  envelope-cell ;  they  are  incapable  of  any 
propagation,  and  pass  immediately  into  the  condition  of  rest.  Alex.  Braun 
has  called  these  forms  of  Chlami/clococcus,  which  develope  an  envclo23e-cell, 
macrof/onidia,  and  distinguished  the  smaller  ones  originating  from  multifold 
di\asion,  as  microgonkUa.^' 

The  division  of  the  spore-  or  red  resting- cells  of  ChJamydococcus  into  two, 
and  then  into  foui'  segments,  each  producing  a  new  generation  of  resting- 
cells,  has  of  late  been  questioned  by  Cohn  and  Wichura ;  but  Mr.  Ciu'rey 
believes  he  can  confirm  this  occurrence,  since  he  has  "  distinctly  observed 
the  process  of  self- division  in  some  red  resting- cells,  which  were  probably 
those  of  Cldamydococcus.  I  say,"  he  writes,  ^^  prohahly,  because  the  red 
resting-cells  of  Cldamydococcus  are  quite  undistinguishable  from  those  of 
another  of  the  Volvocinece,  viz.  SteplianospTia?ra  pluvialis,  so  that  without 
following  out  the  development  it  is  impossible  to  predicate  whether  such  red 
cells  belong  to  one  or  the  other."  (J.  M.  S.  1858,  p.  209.)  A  further  refer- 
ence to  this  topic  will  be  found  in  the  account  of  Stephanosph(xra. 

On  reviewing  his  history  of  Cldamydococcus  (Protococcus)  pluvicdis,  Cohn 
attributes  to  this  plant  an  '  alternation  of  generations,'  and  points  out  the 
periodicity  observed  in  the  appearance  in  a  collection  of  water  of  the  several 
phases,  the  one  replacing  the  other  {On  Protococcus,  R.  S.  1853,  pp.  549,  550). 
Subsequently  he  details  the  number  of  very  various  and  changing  forms  of 
develojmient  it  passes  through,  '^  which  have  been  either  erroneously  arranged 
as  distinct  genera  or  at  least  as  remaining  stationary  in  those  genera,  although 
in  fact  only  transitional  stages  "  (p.  559).  "  Thus,"  he  continues,  "  the  '  stiU ' 
Protococcus-ee]l  (XIX.  20)  corresponds  to  the  common  Protococcus  coccoma 
(Kg.)  ;  when  the  border  becomes  gelatinous  it  resembles  P.  pidcJier,  and  the 
small  cells  P.  minor.  The  encysted  motile  zoospores  are  the  genus  Gyges 
granulum  among  the  Infusoria,  resembling  also  on  the  other  side  P.  turgidus 
(Kg.),  and  perhaps  P.  versatUis  (Braun).  The  zoospores  divided  into  two  must 
be  regarded  as  a  form  of  Gi/ges  hipartitus,  or  of  P.  dimidiatus.     In  the  quadri- 


OP  THE  PHYTOZOA.  151 

partite  zoospores  with  the  secondary  cells  arranged  in  one  plane,  vre  have  a 
Gonium.  That  with  eight  segments  corresponds  to  Pandorina  Monim,  and 
that  with  sixteen  to  Botnjocijstis  Volvox.  When  the  zoospore  is  divided  into 
thirty- two  segments,  it  is  a  Uvella  or  Sijncrypta  (XIX.  27).  When  this 
form  enters  the  '  still '  stage,  it  may  be  regarded  as  a  form  analogous  to 
Microhcdoa  protogenita  ;  this  Algal  genus  is  probably,  speaking  generally, 
only  the  product  of  the  ?7i'e??« -division  in  the  Eughnce  or  other  green  forms. 
The  naked  zoospores  (XIX.  28),  finally,  would  represent  the  form  of  a 
Monad  or  of  an  Astasia  (XIX.  29) ;  the  caudate  variety  approaches  that  of 
a  BodoJ' 

Perty  has  devoted  several  pages  to  recount  his  own  obsei-vations  and  ex- 
periments on  the  genus  CJdamydococcus,  or,  as  he  prefers  to  call  it,  Hysgi- 
num.  He  institutes  two  species,  which  he  states  to  be  equivalent  to  Proto- 
coceus  ]yluvialis  and  P.  nivalis  of  other  authors,  and  insists  on  their  specific 
distinctness.  Probably,  he  adds,  other  varieties  of  Protococcus  coloiu'ed  red 
are  also  referable  to  this  genus,  at  least  such  of  them  as  present  an  animal 
phase  of  existence.  To  his  mind,  the  vital  phenomena  of  such  organisms 
are  best  explicable  on  the  supposition  of  an  animal  nature  ;  for,  says  he, 
cells  which  move  altogether  like  Infusoria,  and  exhibit  sensation  in  their 
yoimg  conchtion,  so  long  as  they  j)resent  such  phenomena,  are  not  vegetable 
cells.  Moreover,  he  thinks  it  established  concerning  the  Phytozoa  in  general, 
that  in  certain  stages  of  their  life  they  sometimes  belong  to  one,  and  in 
others  to  another  kingdom  of  nature,  or  are  so  nearly  allied  to  both  that  a 
separation  is  impossible. 

After  the  space  akeady  devoted  to  the  structure  of  Chlamydomonas  and 
Chlamydococcus,  an  abstract  of  Perty's  long  contribution  on  the  subject  can- 
not be  introduced ;  and  indeed,  apart  from  his  diiferent  interpretation  of 
their  vital  phenomena,  little  could  be  produced  not  included  in  Cohn's  com- 
plete examination.  There  is,  however,  a  paragraph  in  Mr.  Carter's  just 
published  valuable  contribution  on  Eudoyina,  referring  to  Chlamydococcus, 
which  must  not  be  omitted.  He  writes  {A.  N.  H.  1858,  ii.  244)  :  "  Chlamy- 
dococcus undergoes  the  same  kind  of  changes  in  development  as  Eudorina, 
from  which  it  only  differs  in  structiu-e  in  being  smaller  and  globular  instead 
of  ovoid,  in  the  absence  of  an  external  envelope,  and  in  the  ciha  of  the 
daughter- cells  being  included  within  the  parent-cell ;  hence  it  also  difi'ers  in 
being  motionless,  though  the  compartments  of  the  daughter- cells  are  suffi- 
ciently large  for  them  to  tiu-n  round  and  move  their  cilia  freely  therein, 
which  they  are  continually  doing.  The  primary  cell  of  Chlamydococcus,  like 
that  of  Eudorina,  divides  up  into  two,  four,  eight,  or  sixteen  cells,  and  those 
of  the  eight-  and  sixteen-di\-isions  again  into  groups  of  sixteen  or  thirty-two 
each,  so  as  to  resemble  the  thii^d  stage  of  Eudorhia.  Hence  we  may  perhaps 
infer  that  its  fecundating  process  is  similar  to  that  of  Eudorina ;  but  this 
remains  to  be  discovered.  Chlamydococcus  has  also  a  great  tendency  to  stop 
at  the  two-  and  four-division,  from  which  it  may  pass  into  the  '  stilL '  or 
Protococcus-f orm.,  and,  floating  on  the  water  in  a  kind  of  crust,  present  ceUs 
of  all  kinds  of  sizes  undergoing  '  still'  division.  "In  aU  its  multiplications, 
partial  and  entire,  however,  it  generally  maintains  its  primary  or  spherical 
foiTu,  and  does  not  become  ovoid  or  oblong  like  the  groups  of  Eudorina, — the 
only  exceptions  being  in  the  two-  and  four-division,  where  the  green  cells 
are  sometimes  ovate  (probably  from  want  of  room  in  the  parent  capsule),  as 
represented  by  Ehrenberg  in  C.  Pulvisculus,  to  which  I  should  refer  it,  had 
he  not  also  given  an  ovate  form  to  the  type-cell  of  this  species :  nor  can  I 
refer  it  to  C.  pluvialis ;  for  in  all  the  changes  I  have  yet  seen  it  undergo,  the 
red  colour  has  not  increased  beyond  the  minute  eye-spot,  while  this  also  dis- 


152  ge:neeal  history  of  the  ineusokia. 

appears,  and  the  cilia  too,  when  this  species  passes  into  the  '  still '  form. 
Here  it  undergoes  the  same  kind  of  division  that  it  does  in  the  active  state  ; 
but  the  parent-cell,  instead  of  becoming  distended  by  imbibition,  remains 
closely  attached  to  the  daughter- cells,  so  as  to  give  the  group  a  mulberry 
shape.  How  long  it  remains  in  the  '  still '  form  I  am  ignorant ;  but 
having  only  seen  it  in  the  active  state  during  the  months  of  May,  June,  and 
August,  and  throughout  the  rest  of  the  year  in  the  '  still '  one,  I  am  in- 
clined to  think  that  it  only  comes  into  the  active  state  during  the  summer 
months,  and  then  for  the  purpose  of  fecimdation. 

"  In  several  instances,  also,  where  I  have  found  this  Chlamydococcus  with 
Eudorina,  they  have  been  accompanied  by  long  Closteriform  cells.  It  was 
the  case  in  that  above  mentioned,  where  the  latter  was  imdergoing  impreg- 
nation. Some  of  these  have  an  eye-spot,  which,  with  the  natui'e,  arrange- 
ment, and  general  aspect  of  theii*  internal  contents,  shows  that  they  belong 
to  the  class  of  organisms  with  which  they  are  associated.  Theii'  cell-wall 
also  is  more  or  less  plastic,  or  was  so  when  they  were  assuming  this  spicular 
form ;  for  many  have  one  or  more  diverticula  extending  from  them,  some  are 
bifid,  and  a  few  irregularly  stellate.  AMiat  they  are,  I  know  not ;  but  Dr. 
Cohn  has  figured  the  same  kind  of  cells,  in  company  with  Splicei-o_pha  annu- 
lina,  under  impregnation." 

Mr.  Currey  {op.  cit.  p.  216)  has  noticed  and  figured  what  he  conceives  to  be 
a  generative  variety  of  Chlamydococcus  (XX.  24).  "  This,"  he  says,  "  I  take 
to  be  a  state  of  Chlamydococcus.  The  outer  membrane  was  colourless,  and 
the  two  internal  globular  cells  of  a  clear,  bright  ruby  crimson.  The  pecu- 
liarity of  the  plant  consisted  in  the  fact  of  the  cell  being  filled  with  minute 
staff"- like  subcylindrical  bodies  in  active  motion,  precisely  similar  to  the 
spermatozoa  of  Vaucheria.  I  watched  these  bodies  at  inten^als  for  about 
twenty-four  hours ;  and  the  motion  was  incessant.  At  the  end  of  that  time 
the  cell  slipped  amongst  some  other  AlgsG  on  the  same  shde  and  was  lost. 
Whether  these  little  active  organisms  wxre  reaUy  spermatozoa,  or  whether 
they  belonged  to  the  mysterious  bodies  w^hich,  in  some  way  or  another,  are 
supposed  to  find  their  Avay  from  without  into  the  cells  of  Algae,  it  is  im- 
possible to  say." 

The  next  figm-e  (XX.  25)  is  also  copied  from  Mr.  Currey,  and,  as  he  re- 
marks, evidently  "  represents  the  final  stage  of  some  Yolvocineceva.  which  the 
gonidia  have  become  encysted."  We  allude  to  it  here,  although  it  does  not 
belong  to  Chlamydococcus.  Mr.  Currey  observes  further,  "  I  notice  it  be- 
cause the  encysted  cells  were  of  a  pale  yeUowish-brown  colour,  and  covered 
with  minute  pits  or  depressions,  and  were  altogether  different  from  those  of 
any  other  Alga  with  which  I  am  acquainted.  In  Pandorina  and  Stephano- 
Sjphcera  the  resting- spores  are  red,  in  Volvox  bright  orange;  and  in  neither 
case  are  there  any  such  marldngs  as  those  in  the  membrane  of  the  cells 
showTi  in  the  figure  referred  to." 

GoNiUM  (XIX.  32-37). — This  genus  received  considerable  attention  from 
MuUer  and  Ehrenberg.  The  latter  described  it  as  composed  of  sixteen 
Monads,  resembling  Chlamydomonas  in  all  points  except  in  the  absence  of 
an  ej^e-speck,  collected  together  in  a  quadrangular  tablet,  with  fi'om  three  to 
six  intercommimicating  tubes  or  cords.  Each  Monad  was  said  to  be  enclosed 
in  a  hyaline  lorica,  called  here  a  mantle  (lacenia),  which  it  could  at  times 
quit ;  also  to  have  two  filaments  (proboscides)  extended  from  the  mouth,  re- 
presented by  a  clear  spot  at  their  base ;  several  clear  stomach- sacs,  a  con- 
tractile vesicle,  two  round  sexual  glands,  and  numerous  green  ova.  Detached 
individuals,  he  added,  swam  like  Monads,  in  the  direction  of  the  longitu- 
dinal axis  of  their  bodies,  with  tlic  mouth  in  advance  ;  but  when  in  tablet- 


OF  THE  PHYTOZOA.  153 

like  colonies  sometimes  moved  horizontally,  at  others  vertically,  or  rolled  on 
their  edges  like  wheels  by  the  aid  of  the  pair  of  vibratile  filaments  of  each 
member  projecting  fi-om  the  siuface. 

The  animal  organization  here  represented  is  now-a-days  generally  ignored, 
and  Goaium  takes  up  its  position  among  plants.  Prof.  Cohn  (to  whom  we 
are  so  much  indebted  for  oiu'  knowledge  both  of  Protozoa  and  Protophyta) 
has  contributed  a  valuable  paper  (Entw.  d.  mihr.  Algen  u.  PUze)  on  this  in- 
teresting being,  of  which  we  shall  present  an  abstract. 

The  entii'e  organism  is  invested  by  a  colourless  transparent  muco-gela- 
tinous  envelope  without  any  cellulose  limit-membrane,  whence  it  is  that  this 
common  envelope  has  frequently  passed  imobsen'ed  unless  some  colouiing 
matter,  such  as  Indian  ink,  has  been  added  to  the  water. 

The  figiu'e  varies  according  as  the  plant  is  viewed  from  above  (on  its 
polar  aspect)  or  from  its  side  (on  its  equatorial  aspect),  being  in  the  former 
point  of  view  a  quadiilateral  tablet  with  tnmcated  angles  and  rounded  cor- 
nel's (XIX.  32),  and  in  the  latter  a  flattened  spheroid. 

The  simple  or  primordial  cells  (XIX.  33)  enclosed  in  this  mucous  sheath 
are  sixteen  in  number,  disposed  in  a  imiform  manner,  so  that  fom-  cells, 
leaving  a  square  interval  in  the  centre,  are  bounded  externally  by  twelve 
others,  three  of  which  form  one  of  the  four  sides  of  the  organism  (XIX.  32). 
The  central  ceU  of  the  three  is,  moreover,  not  in  a  line  with  the  other  two 
on  the  same  side,  but  set  nearer  to  the  centre  ;  hence  each  side  of  the  tablet 
is  hollowed  out  in  the  middle.  Closer  research  also  shows  that  each  of  the 
cells  is  not  spherical,  but  polygonal,  the  four  internal  being  six-sided  (hex- 
agonal), the  twelve  peripheral  five-sided  (pentagonal) ;  the  consequence  is, 
angular  intercellular  spaces  are  left,  the  central  of  aU  being  quacbangular, 
and  all  the  rest  triangular.  This  arrangement  of  the  primordial  cells  is 
normally  so  regular,  that  Cohn  represents  it  by  a  geometrical  chagram  ;  still, 
in  aU  tablets  of  Gonium  this  is  not  the  case,  and  particularly  in  very  young 
specimens. 

The  regular  polygonal  contoiu^  of  the  cells  indicates  that  they  are  not 
mere  masses  of  soft  variable  protoplasm,  hke  those  of  Stephanospli<xra,  but, 
on  the  contrary',  are  each  of  them  siUTOimded  by  a  colourless,  hyaline,  deli- 
cate but  firm  membrane,  imposing  on  them  theii'  fixed  form  (XIX.  34). 
This  stiTicture  indeed  is  not  generally  discernible,  unless  by  some  abnormal 
conditions,  or  by  the  occiuTence  of  self-di^dsion  (XIX.  35),  in  which,  as 
only  the  green  contents  are  concerned,  it  comes  to  stand  apart  from  the  latter 
as  a  distinct,  separable  sac.  It  can,  moreover,  be  demonstrated  by  cnishing 
the  cells,  when  the  chlorophyll  escapes  thi^ough  the  rent,  and  leaves  the 
colourless  and  fractiu-ed  case.  Cohn  is  con\inced  that  this  membrane  is 
composed  of  cellulose,  although,  from  the  inability  to  isolate  them,  he  has 
been  unable  to  prove  it  by  chemical  reagents. 

Without  any  preparation  this  investing  membrane  can,  further,  be  detected 
at  the  angles  of  the  cells,  fi'om  each  of  which  it  is  prolonged  in  the  form  of  a 
short  tubular  process,  emptj'  and  colourless,  the  contents  being  restricted  to 
the  general  cavity  of  the  ceU  (XIX.  34).  Each  cell  sends  out  such  a  jDro- 
cess  from  its  several  angles  to  miite  T^ith  a  similar  one  fi^om  each  contiguous 
cell :  in  this  way  are  formed  the  intercurrent  cords  or  canals  alluded  to  by 
Ehrenberg.  It  follows  also  from  this  structure  that  the  link  connecting  the 
angles  of  conjoined  cells,  belongs  one  half  to  one  and  the  other  to  its  com- 
panion-cell. 

The  nature  of  the  Gonhun-QdW^  and  their  connecting  tubes  is  clearly  dis- 
played by  observing  the  changes  consequent  on  the  gradual  evaporation  of 
the  water  about  them.     For  instance,  on  adding  salt  by  degrees,  a  portion  of 


154  GENERAL  HISTORY  OF  THE  rNFUSORIA. 

the  water  included  in  the  cells  is  mthdra^Ti,  whereupon  their  contents  con- 
tract themselves  into  a  globular  form,  revealing  the  investing  membrane  in 
its  entii'e  periphery.  Again,  when  the  mucous  envelope  breaks  up  by  difflu- 
ence,  the  cells  show  a  tendency  to  separate  :  the  link-Kke  canals  are  first 
drawn  out,  and  subsequently  give  way  at  the  point  of  junction  of  the  two 
processes  which  form  them — and  this  mth  such  a  degree  of  elasticity,  that 
the  cells  appear  to  burst  from  one  another  mth  a  spring ;  and  thus  at  length 
the  entire  organism  is  resolved  into  an  irregular  collection  of  cells. 

In  the  immatm^e  period  (XIX.  33-36)  the  outhne  of  the  cell-membrane  is 
spherical ;  for  the  angular  figure  and  the  development  of  the  jimction-pro- 
cesses  are  subsequent  phenomena.  Further,  the  extension  of  the  processes 
at  times  goes  on  so  far  that  the  Gonhmi-ceRs  at  fii'st  sight  appear  detached 
from  each  other  and  free,  which  is  never  the  case  natui^ally. 

In  other  points  of  organization  the  cells  of  Gonium  correspond  with  other 
loricated  swarm-cells,  particularly  with  those  of  Chlami/domonas.  Their  con- 
tents consist  of  protoplasm  coloured  by  chlorophyll,  among  which,  in  older 
specimens,  are  numerous  corpuscles  (the  ova  of  Ehrenberg)  that  impart  a 
deeper  coloiu^ing  ;  of  a  central  circumscribed  darker  corpuscle,  which,  as  par- 
ticipating in  every  act  of  fission  of  the  cell,  must  be  esteemed  a  nucleus ;  of 
several  vacuoles,  often  numerous  but  occasionally  wanting,  and  of  two  or 
three  sharply- defined  vesicular  spaces,  constant  in  position  at  the  base  of  the 
filaments  (XIX.  33).  The  last-named  are  the  locomotive  organs  of  the 
organism,  are  two  in  number,  and  proceed  from  the  protoplasm,  passing 
through  foramina  in  the  special  celL-wall,  and  afterwards  through  the  com- 
mon mucilaginous  envelope,  so  as  to  appear,  in  the  polar  aspect,  like  out- 
stretched fibres  from  the  tabular  organism. 

The  movements  of  Gonium  resemble  in  all  respects  those  of  Steplianosphcera 
and  Chlcwiydococcus  and  other  swarm-cells.  The  plant  revolves  on  its  short 
axis,  so  that  in  its  polar  aspect  it  appears  like  a  rotating  surface,  whilst  in  its 
equatorial  it  has  on  the  contrary  a  linear  outhne. 

In  the  coui'se  of  its  development  by  self- division,  neither  the  general  mu- 
cilaginous coat  nor  the  cell-membrane  is  concerned,  but  only  the  contents. 
The  fission  into  16  segments  to  form  a  new  colony  has  not  that  simultaneous 
character  which  Ehrenberg  implies,  but  takes  place  by  four  stages  or  genera- 
tions, in  every  one  of  which  a  bisection  of  each  ceU  already  developed  ensues 
(XIX.  35).  It  is  only  in  fully  developed  Goni wn-tahlets  that  self-division 
is  effected — for  example,  in  such  as  have  cells  ^-J-u'"  i^^  diameter,  and  sepa- 
rated from  one  another  by  the  elongated  intercommunicating  processes,  and 
w^here  those  cells  have  the  disposition  described  as  characteristic. 

On  the  completion  of  the  act  of  self-division  by  the  construction  of  16 
small  cells,  these  are  found  occuppng  just  the  same  relative  position  within 
the  membrane  of  their  parent-cell  as  do  the  members  of  a  perfect  Gonium 
(XIX.  36).  Amid  numerous  examples  of  the  plant,  specimens  may  be  met 
with  abnormal  in  the  number  of  constituent  cells ;  for  instance,  colonies  of 
only  8  cells  occur,  which  are  exphcable  on  the  supposition  that  the  last 
stage  of  fission,  i.  e.  the  last  act  of  generation,  has  been  arrested,  and  only 
three  such  acts  completed.  The  like  irregularities  are  often  noticed  in  other 
Volvocinece. 

The  primordial  cells  of  the  newly  generated  colonies  appear  unconnected 
with  each  other,  whilst  the  mother- cell  wall,  which  still  includes  them,  is 
considerably  distended  and  elongated  in  one  direction  (XIX.  30).  The  move- 
ment of  the  colony  as  a  whole  continues  until  the  last  stage  of  fission  is  com- 
pleted, whereupon  it  ceases,  and  the  newly  formed  groups  commence  a  move- 
ment within  their  enclosing  cell,  sometimes  presenting  themselves  in  one 


OF  THE  PHYTOZOA.  155 

plane  as  a  disc  formed  hy  a  collection  of  green  globules,  at  others,  on  their 
edge,  looking  little  more  than  a  green  line. 

At  length  the  mother-cell  ruptm-es,  and,  the  mucous  envelope  having  dis- 
appeared at  a  previous  stage  (XIX.  37),  the  yoimg  colony  escapes  into  the 
suiTounding  water,  moves  fi'eely  about,  and  commences  an  independent  ex- 
istence. These  young  forms  have  usually  a  diameter  of  j^'".  Supposing, 
which  is  very  probable,  that  a  young  Gonium  after  24  hoiu's  is  capable  of 
development  by  fission,  it  follows  that  under  favoui'able  conditions  a  single 
colony  may  on  the  second  day  develope  16,  on  the  third  256,  on  the  foiu'th 
4096,  and  at  the  end  of  a  week  268,435,456  other  organisms  like  itself. 
This  calculation  sufiiciently  explains  the  extremely  rapid  multii)Hcation  of 
these  organisms,  coloming  a  collection  of  water,  floating  on  its  surface  as  a 
scum,  or  settled  in  bad  weather  as  a  filmy  stratum  at  the  bottom. 

The  cells  which  break  away  from  the  group,  and  so  leave  vacuities  in  its 
conformation,  resemble  in  their  isolated  condition  the  ceUs  of  Clilamydomonas. 
Such  detached  cells  were  deemed  by  Ehrenberg  equally  capable  of  fission  as 
the  persistent  members  of  a  colony ;  Cohn,  however,  has  never  observed  the 
phenomenon,  and  believes,  on  the  other  hand,  that,  after  swarming  for  a  time, 
they  enter  into  a  state  of  rest,  and  by  shedding  their  locomotive  filaments 
assume  the  Protococcoid  state.  This  '  still '  form  of  the  Gonium-(ie\\.s,  is  in  aU 
likehhood  also  entered  upon  when  the  water  in  which  they  live  is  dried  up 
and  the  functions  of  life  suspended ;  and  it  may  be  that  on  the  addition  of 
fresh  water  such  cells  give  issue  to  motile  forms,  and  thus  a  j^araUel  series  of 
changes  occiu'  in  tliis  organism  to  that  observed  in  Stephanosphcera.  Xever- 
theless  a  resting-stage  of  Gonium  is  not  positively  demonstrated ;  for  although 
analogy  is  in  favour  of  it,  and  the  occurrence  of  Protococcoid  cells  in  com- 
pany mth  the  ordinary  tabular  groups  suggests  the  probability  that  these 
are  '  still '  cells,  yet  the  absence  of  characters  to  distinguish  them  from  the 
swarm-spores  of  other  Algae  renders  their  determination  at  best  a  matter  of 
doubt. 

Development  by  fission  as  described  is,  therefore,  the  only  mode  proved  to 
exist ;  it  resembles  that  in  Chlamyclococcus  and  St(]}hansophcera ,  by  which 
macrogonidia  are  formed.  The  production  of  microgonidia,  as  seen  in  both 
the  genera  just  named,  as  well  as  in  Eudorina  {Pandorina)  and  Volvox,  is  as 
yet  unkno^vn  in  Gonium. 

Respecting  its  relation  to  other  Volvocinece,  it  is  to  be  observed  that, 
although  there  are  striking  differences,  there  are,  on  the  other  hand,  decided 
natui'al  afilnities  betwixt  them  and  Gonium.  Thus,  although  the  envelope - 
cell  is  so  imperfectly  developed  that  it  cannot  be  represented  as  a  special 
shut  sac,  as  in  the  case  of  Stejjhanosjjluera,  Chlamydococcus,  &c.,  yet  it  is 
analogous  to  the  envelope-cell  of  those  genera  in  its  relation  to  the  cell-con- 
tents ;  and,  besides,  in  the  case  of  the  intimately  allied  Eudorina  eJegans,  the 
common  envelope,  which  resembles  that  of  SteijJianosplKxra,  is  found  fii^st  as 
a  simple,  and  later  as  a  double  fine  cell- membrane.  (In  Pandorina,  indeed. 
Professor  Henfrey  asserts  the  mucous  envelope  to  be  devoid  of  a  limiting 
membrane.) 

Again,  the  primordial  cells  of  Gonium  are  enclosed  in  a  special  membrane, 
and  not  mere  globules  of  protoplasm  unprotected  save  by  a  pellicular  layer  of 
the  same  substance  ;  thus  the  disposition  in  Gonium  (the  primordial  cells 
enclosed  by  a  membrane,  the  envclope-ceU  not  invested)  is  just  the  reverse  of 
that  in  Chlami/dococcus,  ChJamydomonas,  and  Steplianosjjlupra.  However,  the 
existence  of  a  membrane  aroimd  the  primordial  cells  is  not  an  anomalous  cir- 
cumstance among  the  Volvocinece,  since,  in  certain  stages  of  development,  a 
firm  closely  applied  membrane  is  produced  around  the  cells  of  the   other 


156  GENEEAL  HISTORY  OF  THE  IXEUSOEIA. 

genera — as,  for  example,  around  the  microgonidia  of  Cldamydococcus  Avhen 
they  enter  on  their  resting- stage,  and  about  the  cells  of  Istejjhanosjplicera 
when  preparing  to  leave  the  common  envelope.  But,  fmiher,  in  these  in- 
stances, when  this  special  closely  apj^lied  membrane  appears,  the  envelope-cell 
breaks  uj)  into  a  mucilaginous  layer,  and  then  presents  the  noimal  condition 
of  that  of  Oonium.  In  other  structural  matters,  in  the  number  of  vibratile 
filaments,  and  in  the  history  of  development,  Gonium  entirely  accords  ^^'ith 
the  other  genera. 

After  this  review  of  the  affinity  of  Gomum  with  the  other  Volvoeinece,  it 
follows  that,  hke  them,  it  must  be  of  a  vegetable  natui'c,  although  cellulose 
has  not  been  detected  in  it.  Still  more,  the  evident  relation  of  Gonium  with 
Pediastrum  (II.  44),  the  plant-natiu'c  of  which  no  one  at  the  present  day  ^vill 
gainsay,  points  to  the  same  natural  position.  It  agrees  with  that  plant  in 
general  stnicture,  in  the  union  of  several  cells  in  one  j)lane,  in  the  number  of 
those  cells  and  in  their  self-fission  in  the  power  of  two,  in  the  development 
of  new  tablets  and  in  obedience  to  the  same  laws.  The  only  difference 
between  these  two  genera  is,  that  in  Pediastrum  the  swarming  of  the  cells, 
although  sui'rounded  by  a  common  envelope- cell,  ceases  when  they  are  asso- 
ciated together  in  a  tabular  form, — whilst  in  Gonium  the  reverse  is  seen,  the 
power  of  motion  becoming  manifest  when  the  several  cells  are  in  combination. 
To  state  tliis  generally :  in  Pediastrum  the  indi\idual  cells  swarra,  and  the 
colony  is  quiescent ;  in  Gonium  the  colony  swarms,  and  the  quiescent  state 
of  the  several  cells  follows  upon  their  separation. 

However,  there  are  organs  in  Gonium  which,  did  they  admit  of  proof  as 
essentially  animal  structuiTS,  would  be  fatal  to  all  these  arguments  for  its 
vegetable  natui^e.  These  are  the  two,  or  more  rarely  three,  permanent 
vacuoles  visible  near  the  ongin  of  the  -vdbratile  filaments,  which  are  seen  to 
contract  and  expand  alternately  within  a  brief  interval.  These  contractile 
vesicles  have  a  sharp  outline,  are  colouiless,  and  look  like  clear  rings  in  the 
midst  of  the  green  cells.  To  detect  them  and  their  movements,  the  most 
translucent  and  large  cells  must  be  chosen ;  they  must  also  be  perfectly  still, 
and  lie  flat  upon  the  glass  shde, — an  object  attainable  by  a  partial  evaporation 
of  the  di^op  of  water. 

The  two  vacuoles  (XIX.  33)  are  but  little  apart,  equally  clear  and  large, 
and  apparently  unconnected.  Their  action  is  alternate,  each  vacuole  under- 
going a  systole  and  diastole  in  succession,  whilst  the  time  occupied  by  the 
systole,  by  the  diastole,  and  by  the  interval  is  equal.  The  same  equality 
in  time  obtains  also  between  the  two  vacuoles  of  the  same  cell.  Likewise  a 
uniformity  prevails  among  the  difi'erent  cells  of  the  same  Gonium,  but  not 
among  the  cells  of  different  specimens ;  and  Cohn  holds  the  occiuTcnce  of 
rhji:hmical  contractions  of  these  vacuoles  as  a  well-established  fact. 

These,  therefore,  are  pulsating  spaces,  filling  up  T\ith  water,  and  after  a 
time  expelling  it,  and  agree  in  all  points  with  the  so-called  '  seminal  vesicle ' 
of  Ehrenberg  (the  contractile  sac  or  vesicle  of  other  authors)  met  with  in 
ciliated  Infusoria.  Cohn  next  proceeds  to  discuss  the  question  if  these  pul- 
sating sacs  are  to  be  considered  exclusively  animal  organs,  and  anives  at  the 
conclusion  that  they  cannot  be  so  considered,  and  cannot  be  appealed  to  in 
the  decision  of  the  question  of  the  animal  or  vegetable  natui'e  of  any  doubtful 
organism. 

To  conclude  this  complete  history  of  Gonium,  as  abstracted  from  Cohn's 
elaborate  essay,  we  must  add  that  the  description  applies  only  to  Gonium 
■pectorale  (Ehr.),  which,  in  the  author's  opinion,  is  the  only  species  referable 
to  the  Volvocinece,  the  remainder  enumerated  by  Ehrenberg  being  members 
of  the  genus  Merismospedia  of  the  PaJmellacece. 


OF  THE  PnYTOZOA.  157 

Paxdoeixa  (XIX.  59-G9 ;  XX.  22,  23).— This  genus  has  recently  been 
very  carefully  and  thoroughly  examined  by  Prof.  Henfrey  {J.  M.  S.  1856, 
p.  49)  in  an  able  memoir,  of  which  we  shall  make  free  use  to  sujDply  our 
readers  with  a  satisfactory  description  of  this  interesting  and  beautiful  or- 
ganism. The  specimens  examined  were  of  the  species  Pandorina  Morum, 
of  which,  as  Prof.  Henfrey  justly  remarks,  the  description  "  given  by  Ehren- 
berg  is  so  incorrect,  that  no  one  would  be  able  to  determine  the  organism  by 
its  aid ;  but  the  figiu'es  in  the  Infusionsfhierchen,  although  nide,  are  sufficient 
for  identification."  Dujarchn  contributed  nothing  to  our  knowledge  of  this 
genus,  which  he  treated  as  one  with  Eudorina,  objecting,  veiy  justly,  to  the 
worthlessness  of  the  red  speck  as  a  distinctive  generic  character  between  them. 

Prof.  Henfrey's  account  is  so  succinct  that  it  admits  of  no  abridgement,  we 
are  therefore  induced  to  present  it  entiiT.  "  The  forms,"  he  writes  (p.  50, 
op.  cit.),  "presented  by  this  organism  are  exceedingly  varied;  and  nothino- 
can  be  more  beautiful  than  a  number  of  them  revolving  slowly  on  their  long- 
axes  in  a  di'op  of  water,  as  seen  under  a  power  of  about  100  diameters.  In 
the  fii'st  place,  the  perfect  form  exhibits  two  patterns  (shown  in  XIX.  figs. 
59  and  60) ;  and  there  are  minute  countei-parts  to  these,  remaining  in  that 
state,  while,  in  the  water  whore  the  species  is  actively  multiphdng,  aU  sizes 
between  fig.  64:,  just  emerged  from  the  parent  frond,  and  the  full-grown  form, 
figs.  59  and  60,  &c.,  occur.  The  form  ^nth  32  gonidia  results  from  the  cell- 
division  going  on  one  stage  fiulher  than  in  the  form  with  16 ;  but  this  dif- 
ference is  fixed  during  the  earhest  stages  of  development,  as  the  form  with 
16  never  changes  into  that  with  32  after  it  has  become  free  from  the  parent. 
In  the  perfect  forms  the  gonidia  are  arranged  near  the  peripheiy  of  the  frond 
in  cii'cles,  like  the  equator  and  parallels  of  latitude  on  a  globe, — so  that  Pan- 
dorina resembles  Cohn's  Stephanosijha'ra  more  closely  than  any  of  the  other 
Volvocinece,  that  ha\*ing  a  single  equatorial  ring  of  gonidia  in  its  globular 
frond.  Among  the  forms  with  the  isolated  gonidia  occm^  others  almost  equally 
numerous  with  the  gonidia  collected  together  into  berry-like  heaps  (figs.  65- 
68) :  these  are  smaller  than  the  others,  but  equally  varied  in  dimensions ; 
their  gonidia  resemble  those  of  the  other  form;  they  ajDpear  destined  to 
form  the  resting-spores. 

''  The  gonidia  are  almost  globular  ;  they  have  no  proper  membrane,  but 
consist  of  a  gelatinous  granular  substance  which  contains  a  thinner  fluid  in 
the  centre,  as  it  contracts  strongly  by  exosmosis  when  strong  saline  solutions 
are  applied.  There  is  a  large  nucleus-like  body  (the  chlorophyll-vesicle  of 
A.  Braun)  at  the  posterior  end  of  the  gonidium  (fig.  61)  ;  and  at  the  opposite 
side  is  a  short  beak-like  process,  with  a  colourless  space  behind  it :  the  pair 
of  cilia  arise  here ;  and  a  little  to  one  side  and  below  these  is  the  reddish - 
brown  granule  called  the  '  eye-spot.'  AVe  have  never  been  able  to  obseiwe  a 
pulsating  vacuole,  as  described  by  Busk  and  Cohn  in  Volvox  and  Gonium. 

"  The  gelatinous  frond  appears  to  be  perfectly  homogeneous,  without  any 
boundary  membrane.  Iodine  and  sulphuric  acid  do  not  coloiu'  it  blue.  It  is 
tolerably  resistent,  and  appears  solid,  as  it  does  not  give  way  or  become 
indented  by  external  pressure,  as  is  the  case  with  the  hollow  frond  of  Vohox. 

''The  fronds  are  multiplied  by  the  conversion  of  the  gonidia  into  new 
families.  If  they  are  \dewed  at  night,  many  of  the  fronds  may  be  found  at 
rest  at  the  bottom  of  the  vessel  (in  the  daytime  they  assemble  at  the  side 
next  the  Hght),  motionless,  and  Avith  the  gonidia  rounded  and  deprived  of 
their  nucleus.  By  covering  up  the  bottle  from  the  light,  the  development  of 
the  new  fronds,  which  naturally  takes  place  very  early  in  the  morning,  may 
be  retarded,  so  as  to  be  followed  during  the  morning  until  noon.  Some  of  the 
fronds  may  be  found  with  the  gonidia  converted  into  berry-like  heaps  (fig.  62), 


158  GENERAL  HISTOHY  OF  THE  INFUSORIA. 

others  with  the  gonidia  abeady  distinct  (fig.  63),  while  many  parent  fronds 
present  the  young  fronds  more  or  less  regularly  arranged  in  the  softened 
and  expanded  parent  mass,  which  ultimately  dissolves  and  sets  them  free 
(fige.  64,  65).  They  then  increase  in  size  in  proportion  to  the  favoiu^able 
conditions  in  which  they  are  placed.  I  have  never  seen  anything  like  what 
are  described  by  Cohn  in  Ste_phanos])licera  as  '  microgonidia.'  In  a  letter  re- 
ceived from  Professor  A.  Braun  since  the  above  was  written,  he  speaks  of  the 
forms  mth  small  gonidia  (fig.  64)  as  the  '  microgonidial '  form. 

''When  kept  for  some  weeks,  an  increasing  quantity  of  fi-onds  became 
accumulated  at  the  bottom  of  the  water,  and  these  chiefly  of  the  character 
shown  in  fig.  QQ,  but  devoid  of  ciha ;  and  while  many  of  them  decayed,  in 
others  the  gonidia  became  encysted  so  as  to  form  globular  cellules.  Left  for 
a  fortnight,  the  water  was  found  without  a  trace  of  green  colour,  with  merely 
a  broA\Tiish  sediment  at  the  bottom,  upon  examining  which,  it  was  found  to 
contain  a  large  number  of  berry-like  forms  with  the  gonidia  not  only  en- 
cysted, but  with  their  contents  converted  into  a  red,  oily,  granular  substance 
(figs.  67,  68),  as  in  the  resting- spores  of  many  Confervoids.  The  gelatinous 
frond  was  here  almost  dissolved  away ;  and  a  slight  pressure  was  suificient  to 
detach  and  separate  the  cellules,  which  are  doubtless  resting-spores  (fig.  69) 
and  destined  to  become  subsequently  developed  into  new  fronds.  This  remains 
to  be  decided. 

"  The  organism  thus  described  is  a  well-marked  and  distinct  species,  very 
diff'erent  from  Volvox  and  Gonium,  but  approaching  near  to  StephanosjphcEra. 
The  form  which  produces  the  resting-spores,  after  losing  its  ciha,  is  Kiitzing's 
Botryocystis  Mornm.  I  have  met  with  a  form  hke  this  not  imfrequently,  but 
never  before  with  the  perfect  Pandorlna.  Mr.  Pollock  tells  me  that  he  has 
collected  from  the  same  pond  for  some  years  past,  but  never  found  Pandorina 
before,  and  yet  it  colours  the  water  green  this  season.  VoJvox  seems,  in  Hke 
manner,  to  come  and  go  at  intervals  of  years,  its  revivification  from  the  rest- 
ing-spores depending  much  on  external  conditions." 

Mr.  CiuTey's  valuable  contribution  to  oiu"  knowledge  of  the  British  freshwater 
Algae  {J.  M.  S.  1858,  p.  213)  furnishes  the  following  memoranda  on  Pan- 
donna.  He  writes — "  In  speaking  of  the  reproduction  of  Pandorina,  Mr. 
Henfrey  mentions  two  processes  :  1.  the  conversion  of  each  gonidium  into  a 
new  frond  wdthin  the  parent  mass  ;  and  2.  the  conversion  of  the  gonidia  into 
encysted  resting-spores,  which  are  set  free,  and  subsequently  germinate  to 
produce  new  fronds.  Upon  this  I  may  remark,  that  the  process  of  becoming 
encysted  does  not  invariably  take  place  ivithin  the  parent  frond,  for  I  have 
seen  the  gonidia  of  Pandorina  escape  from  the  parent  frond  in  the  form  of 
membraneless  active  zoospores  ;  and  although  I  was  not  fortunate  enough  to 
trace  the  subsequent  fate  of  these  zoospores,  the  probabihty  is  that,  like  those 
of  CJdamydococcus  and  Gonium,  they  would  become  encysted  at  a  subsequent 
period,  as,  without  undergoing  this  process,  it  is  difficult  to  see  how  they  could 
produce  new  fronds.  This  mode  of  escape  of  the  zoospores  seems  to  throw 
some  doubt  upon  the  suggestion  of  Mr.  Henfrey  with  regard  to  the  nature  of 
the  frond  of  Pandorina,  which  he  considers  to  be  sohd,  inasmuch  as  it  does  not 
give  way  or  become  indented  by  pressure,  as  is  the  case  with  the  hollow  frond 
of  Volvox.  If,  however,  the  frond  were  solid,  the  zoospores  could  not  well 
escape,  except  by  its  gradual  dissolution  ;  but,  in  the  instance  I  have  men- 
tioned, the  escape  certainly  took  place  by  a  rupture  (as  may  often  be  seen 
with  Volvox),  and  not  by  a  gradual  process  of  dissolution.  In  a  paper  on 
some  Volvocinece  by  Dr.  Fresenius,  in  the  second  volume  of  the  Transactions 
of  the  Senckenberg  Natural  History  Society,  he  speaks  of  the  easy  escape  of 
the  cells  of  Gonium  pectorah  as  being  evidence  against  the  existence  in  that 


OF  THE  PHTTOZOA.  159 

Alga  of  any  firm  covering,  and  he  draws  a  distinction  in  this  respect  between 
Gonium  and  Pandorina.  My  observation,  however,  leads  me  to  think  that 
Pandorina,  as  far  as  relates  to  its  coat,  does  not  substantially  differ  from 
Vohox  and  Gonium.  Besides  the  natiu-e  of  its  coat,  there  are  some  other 
points  of  structure  in  Pandorina  requiring  fiu'ther  examination  and  elucida- 
tion. Ehrenberg  stated  that  the  gonidia  of  Pandorina  have  one  cilium,  and 
no  eye-spot,  a  view  adopted  by  Fresenius  in  the  paper  I  have  alluded  to. 
Focke  and  Dr.  Braun  considered  Ehrenberg's  observations  inaccurate,  and 
Mr.  Henfrey  agrees  with  them.  As  far  as  my  observations  go,  I  should  say 
that  the  gonidia  have  usually  two  cilia,  but  that  they  frequently  have  no  eye- 
spot.  Mr.  Henfrey  has  never  been  able  to  observe  a  pulsating  vacuole,  nor 
was  any  such  vacuole  visible  in  my  specimens.  Dr.  Eresenius,  on  the  other 
hand,  has  observed  one,  sometimes  two,  such  vacuoles ;  and  he  remarks  that 
cilia  and  red  spots  are  subject  to  considerable  variation,  and  suggests  that 
Stephanospluera  and  VoJvox  are  probably  the  only  distinct  forms  to  be  met 
with  in  the  Volvocinea'.  I  should  protest  against  including  Gonium pectorale  in 
the  same  genus  as  Stephanosphan^a  ;  but,  with  this  exception.  Dr.  Eresenius's 
suggestion  is  probably  correct.  If,  however,  Stcphanosijhcera  and  Pandorina 
are  only  forms  of  the  same  plant,  the  generic  name  '  Stephanosphcera '  must 
give  place  to  '  Pandorina,''  the  latter  being  of  much  earlier  date." 

According  to  Braim  (Kejuv.,  B.  S.  p.  21,  7iote),  the  colonies  of  Pandoinna 
revolve  always  to  the  right ;  but  Prof.  Henfrey  corrects  this  statement,  assert- 
ing that  they  change  the  direction  constantly.  Another  circumstance  re- 
marked by  Braun  is,  that  both  the  birth  of  the  first  generation  of  gonidia, 
and  the  production  of  the  succeeding  generations  by  the  division  of  the  earlier, 
occur  in  the  morning  after  nocturnal  preparation  (p.  224), — a  circumstance, 
indeed,  which  prevails  in  all  the  Volvoclnem.  We  must  also  note  that  among 
the  many  phases  of  development  of  Chlamydococcus pluvialis,  Cohn  discovers 
two  comparable  in  form  to  Pandorina  Morum  and  to  the  Botryocystis  Volvox 
of  Kiitzing  {op.  at.  B.  S.  p.  559). 

The  late  valuable  contribution  of  Mr.  Carter  on  Eudorina  {Pandorina) 
{A.  N.  H.  1858,  ii.  p.  237)  claims  our  especial  attention  as  confirmatory  of 
Cohn's  discovery  of  the  sexuality  of  Volvox,  a  parallel  fact  to  that  he  had  pre- 
viously made  out  in  the  case  of  certain  indubitable  Algae.  Mr.  Carter  identi- 
fies the  organism  he  has  studied  with  the  Eudorina  elegans,  Ehr.,  a  species 
which  natui'alists  at  the  present  day  refuse  to  consider  actually  distinct  from 
Pandorina  nioriim,  inasmuch  as  the  solitary  character  upon  which  the  sepa- 
ration was  made  by  Ehrenberg,  viz.  the  presence  of  a  red  speck  in  Eudorina, 
is  well  known  to  have  no  pretensions  to  a  specific,  and  stiU  less  therefore  to 
a  generic  character.  Indeed,  Mr.  Carter  himself  treats  the  '  eye-spot,'  if  not 
as  a  mere  accidental  feature,  yet  as  only  an  adjunct  of  a  particular  phase  of 
plant-life ;  for  in  the  very  paper  under  notice  he  puts  forward  the  query, 
''  Does  not  the  disappearance  of  the  eye -spot  in  the  '  still '  form  thus  seem  to 
point  out  its  analogy  Avith  the  bright  colours,  especially  the  red,  presented  by 
plants  in  their  flowers  during  the  season  of  fecimdation,  rather  than  wdth  the 
eye  of  animals  ?  " 

We  may  consequently  regard  this  excellent  paper  by  Mr.  Carter  as  an  im- 
portant supplement  to  Prof.  Henfrey's  admirable  and  lucid  memoir  on  Pan- 
dorina, especially  its  developmental  histoiy.  At  the  risk  of  some  repetition,  we 
shaU  allow  the  author  to  explain  his  researches  and  opinions  in  his  own  words, 
and  the  more  so  as  his  plan  of  proceeding  and  manner  of  description  do  not 
tally  very  precisely  with  those  observed  in  the  preceding  account  of  Pandorina. 

"  Before  going,"  Mr.  Carter  writes,  "  to  the  fecundation,  it  is  desirable  that 
we  should  trace  the  development  oi Eudorina  up  to  this  point ;  but  not  ha\ing 


160  GENERAL  HISTORY  OF  THE  INFUSORIA. 

been  able  to  recognize  tliis  organism  in  its  simplest  form  (that  is,  as  a  solitary 
single  cell),  nor  any  stage  of  its  segmentation  prior  to  the  third  degree  of  du- 
plicative subdivision  (that  is,  into  16  cells,  when  the  mother-coverings  have 
di^opped  off),  I  must  begin  from  this  period. 

"  At  this  time,  Avhich  we  will  call  the  first  stage,  the  Eudorina  consists  of  an 
ovoid  green  bod}^,  partially  divided  into  the  number  of  cells  just  mentioned, 
each  of  which  is  provided  with  a  paii*  of  cilia  which  project  through  a  thin 
gelatinous  envelope  that  surrounds  the  whole  mass.  It  is  now  in  its  smallest 
size,  about  5-5400ths  of  an  inch  long,  that  is,  not  more  than  the  diameter  of 
the  Chlmnydococcus-cell,  and  swims  by  means  of  its  cilia,  with  the  small  end 
foremost,  and  with  a  rotatory  motion  on  its  longitudinal  axis,  as  often  from 
right  to  left  as  from  left  to  right.  An  eye-spot  is  also  present  in  each  of  the 
four  anterior  ceUs,  but  seldom  visible  in  the  rest  at  this  period. 

"  As  the  development  progresses  and  the  Eudorina  increases  in  size,  the  di- 
vision becomes  complete,  and  each  cell,  in  addition  to  the  granular  mucus  and 
chloro^Dhyll  which  line  its  interior,  may  now  be  seen  to  be  provided  internally 
Avith  a  spherical  translucent  utricle  (which  is  the  nucleus),  an  eye-spot  situ- 
ated peripheric  ally  and  riiidway  between  the  cilia  and  the  opposite  end  of  the 
cell,  a  contracting  vesicle  at  the  base  of  the  cilia,  and  the  pair  of  cilia  them- 
selves. Each  pair  of  cilia  passes  out  through  a  single  channel  in  the  gelati- 
nous ceU  or  envelope,  which  has  now  become  much  thickened — and  thus  their 
movements  are  Kmited  u^d  to  this  ]3oint, — while  a  defined  line  internally  marks 
the  boundary  of  the  original  cell- wall,  through  which,  of  course,  the  cilia  also 
pass. 

*'  Dui^ing  the  second  stage,  each  of  the  ceUs  again  undergoes  duplicative 
division  (the  nuclei  having  been  doubled  previously)  ;  and  the  whole  organism 
becommg  larger,  they  are  separated  from  each  other,  and  being  no  longer  sub- 
ject to  the  compression  which,  with  the  lines  of  fissiparation  tending  towards 
the  centre  of  the  ellipse,  and  their  confined  position,  induced  a  more  or  less 
conical  and  polygonal  shape,  now  become  spherical  and  enclosed  respectively 
within  distinct  transparent  capsules.  The  Eudorina  is  now  30-5400ths  of  an 
inch  long,  and  contains  thirty-two  green  cells,  which  are  evidently  situated 
between  two  large,  ovoid,  colourless,  transparent  cells,  one  of  which  bounds  a 
similarly-shaped  cavity  in  the  centre  of  the  Eudorina,  and  the  other  is  the 
original  cell- wall,  round  which  again  is  the  newly  secreted  envelope, — while 
the  green  cells  are  further  fixed  in  theii'  respective  positions  by  the  passage  of 
their  ciha  through  the  two  latter,  both  original  cell-wall  and  envelope.  Thus 
we  see  that  the  Eudorina  is  derived  from  a  simjDle  (daughter-)  cell,  and  that 
its  green  cells  have  resulted  from  a  duplicative  subdiv-ision  of  the  green  matter 
Avhich  lined  the  cavity  of  this  cell.  Arrived  at  this  state,  which  we  shall  pre- 
sently see  is  that  of  maturity,  we  also  observe  that  the  posterior  part  of  the 
envelope  becomes  crenulated,  apparently  fi^om  flaccidity. 

"  After  this,  however,  it  again  presents  another  phase,  which  maybe  called 
the  third  or  last  stage  of  development.  Here  each  cell  again  undergoes  a  rapid 
duplicative  subdivision  into  sixteen  or  thirty-two  cells,  which,  in  the  group, 
assume  a  more  or  less  oblong  figui'e  respectively ;  and  thus  the  Eudorina's 
length  is  increased  to  50-5400ths  of  an  inch.  The  internal  structure  now 
gradually  breaks  down  before  the  external  envelope,  when  for  a  short  time 
the  groups  may  be  seen  swimming  about  the  cavity  thus  formed,  tiU  at  last 
the  envelope  bursts  and  they  become  liberated.  AVhat  becomes  of  them  after- 
wards, I  cannot  state  from  observation  ;  but  the  green  cells  having  been  greatly 
reduced  in  size  by  the  latter  subdivisions,  it  is  probable  that  many  of  the 
groups,  if  they  do  not  form  new  individuals,  sooner  or  later  become  disinte- 
grated, and  the  Eudorina  thus  eventually  perishes. 


OF  THE  PHTTOZOA.  161 

"  ^Mien,  however,  the  process  of  impregnation  takes  place,  the  division  stops 
at  the  second  stage, — that  is,  when  the  Euclorina  consists  of  thirty-two  cells  of 
the  largest  kind,  each  of  which  is  about  1 -1866th  of  an  inch  in  diameter 
within  its  capsule,  which  is  therefore  a  little  larger.  The  process  is  as  follows : — 

''  At  a  certain  period  after  the  second  stage  has  become  fully  developed,  the 
contents  of  the  foiu'  anterior  cells  respectively  present  hues  of  duplicative  sub- 
division which  radiate  from  a  point  in  the  posterior  part  of  the  cell  (and  this 
distinguishes  this  subdivision  from  that  which  took  place  in  the  original  cell 
from  which  the  Eudorhia  was  derived,  and  that  which  takes  place  in  the  third 
or  last  stage  of  development  just  described,  where  the  lines  of  fissiparation 
tend  towards  the  centre  of  the  ellipse  or  ovoid  cell).  These  lines,  which  ulti- 
mately divide  the  green  contents  of  the  cell  into  sixty-foiu-  portions,  where 
the  division  stops,  necessarily  entail  (from  their  radiating  from  a  point  and 
terminating  a  little  beyond  the  centre  of  the  cell)  a  pyriform  shape  on  the 
segments,  from  whose  extremities  a  mass  of  cilia  may  be  observed  waving  in 
the  anterior  part  of  the  cell  of  the  parent,  while  yet  her  o^vn  pair  of  cilia  are 
in  active  motion,  and  her  eye-spot  still  exists  in  situ  on  one  side  of  her  pro- 
geny,— thus  showing  that  the  latter  may  be  almost  fully  formed  before  the 
parent  perishes.  At  length,  however,  this  takes  place,  and  the  progeny,  which 
we  shall  henceforth  call  '  spermatozoids,'  separate  from  each  other,  and  finding 
an  exit,  probably  by  iTipture,  through  the  effete  parent-cell  and  her  capsule, 
soon  become  dispersed  throughout  the  space  between  the  two  large  ovoid  cells 
mentioned,  where  they  thus  freely  come  into  contact  with  the  capsules  of  the 
twenty-eight  remaining  or  female  cells. 

"  The  form  of  the  spermatozoid  now  varies  at  every  instant,  from  the  activity 
of  its  movements  and  the  almost  semifluid  state  of  its  plasma  ;  and  therefore, 
if  we  had  not  seen  it  in  the  parent-cell,  it  would  be  very  difficult  to  define 
what  this  form  really  is.  Its  changes  in  shape,  however,  are  confined  to 
elongation  and  contraction,  like  those  of  Euglena  viridis,  and  not  polymorphic 
like  those  of  Amoeba ;  hence  it  is  sometimes  linear-fusiform  or  limular,  at 
others  pyriform,  short,  or  elongate.  The  centre  of  the  body  is  tinged  green 
by  the  presence  of  a  Kttle  chlorophyll,  while  the  extremities  are  colomiess  ; 
the  anterior  one  bears  a  pair  of  cilia,  and  there  is  an  eye-spot  a  little  in  front 
of  the  middle  of  the  body,  also  probably  a  nucleus.  Thus  we  have  a  product 
widely  difterent  from  the  common  cell  of  Eudorina.  It  is  about  l-2700th  of 
an  inch  long,  and  1- 10,800th  of  an  inch  broad. 

''  Once  in  the  space  mentioned,  the  spermatozoids  soon  find  their  way  among 
the  female  cells,  to  the  capsules  of  which  they  apply  themselves  most  vigor- 
ously and  pertinaciously,  flattening,  elongating,  and  changing  themselves  into 
various  forms  as  they  glide  over  their  surfaces,  until  they  find  a  point  of  in- 
gress, when  they  appear  to  slip  in,  and,  coming  in  contact  ^ith  the  female 
cell,  to  sink  into  her  substance  as  by  amalgamation.  I  say  '  appear,'  because, 
the  female  cells  as  well  as  the  spermatozoids  being  so  small,  so  numerous,  and 
so  nearly  grouped  together,  and  there  being  no  point  like  a  micropyle  that  I 
could  discover,  and  the  Eudorina  continually  undergoing  more  or  less  rotation, 
I  do  not  feel  so  certain  of  having  seen  the  act  of  union  take  place  as  if  there 
had  been  only  a  female  ceU  present  with  a  fixed  point  for  the  entrance  of  the 
spermatozoids,  as  in  the  resting-spore  of  (Edogonium.  But  the  act  itself  does 
not  require  to  be  seen ;  for  the  constancy  of  this  form  of  Eudorina,  the  way 
in  which  these  little  bodies  are  produced,  their  plastic  natiu-e,  and  their  be- 
haviour towards  the  female  cells  are  quite  sufiicient  to  conrince  those  who 
have  given  their  attention  practically  to  such  subjects  that  they  are  spermato- 
zoids, and  that  there  can  be  no  other  object  in  their  congregating  about  the 
female  cells  than  impregnation.     If  this  be  not  sufficient,  their  number  may 

M 


162  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

frequently  be  seen  to  diminish  as  they  pass  backward  among  the  female  cells, 
when  their  disappearance  can  only  be  accounted  for  by  their  having  become 
incorporated  with  the  green  cells.  Eudorina  in  this  stage  also  may  frequently 
be  seen  with  all  the  four  anterior  cells  absent,  and  only  a  few  spermatozoids 
left,  most  of  which  are  motionless  and  adherent  to  the  capsules, — indicating 
that  the  rest  have  disappeared  in  the  way  mentioned.  Lastly,  many  Eudorince 
in  this  stage  may  be  observed  with  not  only  the  four  anterior  cells  absent,  but 
with  hardly  a  single  spermatozoid  left, — indicating  that  the  whole  had  passed 
into  the  female  cells,  or  had  become  expended  in  the  process  of  impregnation, 
I  have  never  seen  any  spermatozoids  in  the  central  or  axial  cavity,  nor  do  I 
think  that  there  is  a  means  of  their  escaping  externally  without  rupture  ;  so 
that  their  being  confined  to  the  space  between  the  two  ovoid  cells  of  the  Eu- 
dorina, where  the  green  cells  are  situated,  is  another  reason,  if  any  more  be 
needed,  for  considering  them  fecundating  agents. 

"  What  changes  take  place  in  the  Eudorina  after  this,  I  have  not  been  able 
to  discover.  At  the  time,  the  female  cells  appear  to  become  more  opake  by 
the  incorporation  of  the  spermatozoids  ;  and  the  crenulated  state  of  the  poste- 
rior part  of  the  envelope  in  this  stage  seems  also  to  indicate  an  approach  to 
disintegration.  I  have  also  observed  that  those  Eudorince  which  are  under- 
going, or  apparently  have  undergone  impregnation,  are  less  active  than  the 
rest, — that  is,  those  in  which  the  spermatozoids  are  scattered  throughout  the 
interspace  mentioned  and  applying  themselves  to  the  capsules  of  the  green 
cells,  and  those  in  which  there  are  only  a  few  spermatozoids  left.  But  even 
if  they  did  become  disintegrated,  the  latter,  when  free,  would  so  closely  re- 
semble those  of  Chlamydococcus,  which  was  also  abundantly  present,  that  un- 
less the  Eudorina  could  be  found  undergoing  impregnation  by  itself,  or  apart 
from  this  organism,  there  appears  to  me  no  chance  of  distinguishing  the  two, 
and  therefore  no  other  means  of  completing  this  part  of  its  history.  It  is 
true  that  the  impregnated  cells  may  undergo  some  change  in  form  similar  to 
those  of  Vohox  glohator  after  impregnation ;  but  I  think  I  should  have  seen  this 
among  the  numbers  which  came  under  my  observation,  if  it  had  been  the  case. 

"  While  undergoing  impregnation,  the  female  cells  always  contain  from 
two  to  four  nuclei,  as  if  preparatory  to  the  third  stage  of  development,  into 
Avhich  they  are  sometimes  actually  seen  passing,  Avith  the  spermatozoids  pre- 
sent and  scattered  among  them ;  but  the  effect  of  impregnation  generally 
seems  to  arrest  this  stage,  and  thus  save  the  species  from  that  minute  divi- 
sion which  leads  to  the  destructive  termination  of  Eudorina  already  noticed. 

"  Sometimes  all  the  cells  together  imdergo  the  spermatoid  fissuration,  when 
the  Eudorina  passes  into  Pandorina  Morum,  Ehr. ;  but  in  this  case  the  de- 
velopment does  not  stop  at  the  pyriform  spermatozoids,  but  goes '  on  to  the 
development  of  thirty-two  larger  globular  cells  in  each  group,  similar  to 
those  produced  in  the  third  stage  of  Eudorina  above  described,  when  they 
assume  respectively  a  dome-shaped  form,  held  together  by  a  membrane  which 
is  fixed  to  the  point  in  the  posterior  extremity  of  the  cell  from  which  the 
lines  of  fissiparation  first  radiated.  As  the  groups,  however,  progress  in  de- 
velopment, this  dome  appears  to  become  flatter,  and,  the  Eudorina  breaking 
up,  as  in  the  third  stage,  these  groups,  when  liberated,  finally  appear  to  pass 
into  the  form  of  Goni^nn,  when  I  think  they  perish  like  the  corresponding 
groups  of  the  third  stage.  I  did  not  observe  this  development  (in  which  may 
be  included  some  abnormal  states,  where  only  one  or  two  of  the  spermatic 
cells  fail,  and  one  or  more  of  the  female  cells  take  on  this  mode  of  fissiparation 
irregularly)  until  the  normal  one  of  impregnation  ceased  to  appear.  Ehren- 
berg  was  wrong  in  giving  the  cells  of  Pandorina  and  Eudori7ia  single  cilia,  as 
has  before  been  stated,  and  partly  wrong  in  leaving  out  the  eye-spot,  both 


OF  THE  PHYTOZOA.  163 

of  which,  though  disappearing  ultimately,  indicate  the  continued  life  of  the 
parent-ceU,  as  in  the  development  of  the  spermatozoids,  long  after  the  forma- 
tion of  her  progeny. 

*'  Thus  the  process  of  impregnation  in  Eudorina  agrees  closely  with  that 
described  by  Dr.  F.  Cohn  in  Volvox  ghhator,  in  which  organism  I  had  seen 
some  of  the  cells  of  the  interior  undergoing  a  spermatoid  development  exactly 
like  that  above  described,  and  also  that  pre\'iously  figured  by  Mr.  Busk,  and 
alluded  to  by  him  as  one  of  '  microgonidia ; '  and  therefore  the  moment  I 
perceived  it  in  Eudorina,  in  connexion  with  Dr.  Cohn's  announcement,  I  felt 
conduced  that  the  latter  was  right,  and  that  I  had  before  me  Eudorina  also 
undergoing  a  similar  process  of  fecundation. 

''  So  much  for  the  spermatoid  development ;  let  us  now  retiu'n  to  that  of 
the  Eudorina  in  totality,  concerning  which  there  is  still  an  interesting  ques- 
tion for  our  consideration,  bearing  on  the  early  development  of  this  organism, 
which  I  have  already  stated  my  inability  to  supply,  viz.  how  does  the  sixteen- 
division  of  the  cell  in  the  third  stage  of  development  take  place,  so  as  to  allow 
the  cilia  to  become  external  ?  It  will  be  remembered  that  this  cell  in  the 
second  stage,  before  it  passes  into  the  sixteen -division  of  the  third  stage,  con- 
sists of  its  capsule  or  cell-Avall  and  the  green  contents  ;  and  it  should  also  be 
remembered  that,  although  these  contents  have  now  no  other  covering  distinct 
from  the  protoplasm  but  the  capsule,  yet  in  all  algal  cells,  whenever  the  green 
contents  take  on  a  new  form,  such  as  that  of  a  spore  or  group  of  cells,  a  second 
more  delicate  coveiing  is  separated  from  them,  for  which  I  have  heretofore 
used  the  term  '  protoplasmic  sac  ; '  these  two  coverings,  then,  are  the  parental 
division  of  the  mass,  and  become  caducous  as  the  rest  takes  on  its  new  form 
and  developes  on  its  surface  a  cell-wall.  Thus  we  get  the  sixteen  cells  sepa- 
rated from  their  capsule,  &c.,  and  surrounded  by  their  proper  cell- wall  and 
the  external  envelope,  which  may  be  a  still  further  tliickenmg  of  the  former, 
or  a  new  secretion ;  but,  be  this  as  it  may,  the  cilia  are  seen  outside  it.  And 
at  fii'st  it  might  be  thought  that  they  were  formed  before  either  the  cell-wall 
or  envelope,  so  as  never  to  have  been  enclosed  by  either  ;  but  if  this  were  the 
case,  the  ciha  of  the  sixteen  cells,  which  are  added  by  duplicative  division  to 
the  first  stage  of  Eudorina  to  form  the  second  stage,  should  be  inside  these 
coverings,  or  protrude  through  the  original  sixteen  channels  Avith  the  other 
sixteen  pairs  of  cilia.  However,  neither  is  the  case ;  for  these  sixteen  cells 
have  their  channels  respectively  as  well  as  the  other  sixteen  cells,  in  which 
case  they  must  have  been  made  by  the  sixteen  new  cells  themselves,  unless 
the  thirty-two- division  is  formed  before  the  pelHcle  which  subsequently  forms 
the  cell- wall  is  supplied,  and  our  first  stage  does  not  pass  into  the  second 
stage,  but  both  forms  are  produced  at  once  and  separately  from  the  beginning, 
— a  point  which  can  only  be  determined  by  following  the  development  of  the 
Eudorina  from  the  spore  itself,  and  that,  too,  alone,  since  it  is  impossible  to 
say  whether  the  sixteen -division  groups,  when  previously  mixed  up  with  all 
the  other  forms  of  Eudorina,  are  or  are  not  derived  direct  from  the  spore,  or 
from  the  third  stage  of  development  of  this  organism.  That  the  sixteen -divi- 
sion or  second  stage  may  pass  direct  into  a  similar  form  to  the  third — that  is, 
into  a  form  of  Eudorina  consisting  of  sixteen  groups  of  sixteen  cells  each — I 
have  occasionally  seen  ;  but  then  this  form  has  been  globular  (only  g-JJ^jths 
of  an  inch  in  iameter),  and  not  ovoid,  although  the  groups  have  possessed 
the  latter  form  :  perhaps  this  is  the  spore,  and  the  sixteen  groups  the  young 
Eudorince,  if  not  a  different  species.  Again,  the  robust  individuals  of  the 
sixteen -division  one  would  think  to  be  direct  from  the  spore,  and  to  pass  into 
the  robust  indi\-iduals  of  the  second  stage  or  thirty-two-di\asion, — while  the 
puny,  meagre  individuals  one  would  think  to  come  from  the  third  stage,  and. 

m2 


164  GENERAL  HISTORY  OF  THE  INFUSORIA. 

as  before  conjectured,  end  in  disintegration  and  death.  But  all  this,  as  I  have 
just  stated,  can  only  be  determined  by  following  the  development  of  the  spore 
from  the  commencement.  One  fact  I  might  add,  however,  viz.  that  the  robust 
forms  of  good  size  have  the  power  of  mthdi-awing  theii'  cilia  and  protruding 
them  again ;  this  happens  when  they  are  transferred,  from  the  vessel  in  which 
they  may  be  contained,  to  the  slide  for  examination :  many  may  just  at  this 
time  be  seen  to  be  motionless,  ^vith  the  channels  for  the  cilia  empty ;  but 
gradually  the  cilia  are  protruded  through  them,  and  as  gradually  the  Eudo- 
rina  evinces  increasing  power  of  motion,  until  they  are  fully  protruded,  and 
it  SAvims  away. 

''  Chlamydococcus  undergoes  the  same  kind  of  changes  in  development  as 
Eudorina,  from  which  it  only  differs  in  structm^e  in  being  smaller,  and  glo- 
bular instead  of  ovoid,  in  the  absence  of  an  external  envelope,  and  in  the  cilia 
of  the  daughter- cells  being  included  within  the  parent- cell ;  hence  it  also 
differs  in  being  motionless,  though  the  compartments  of  the  daughter- cells 
are  sufficiently  large  for  them  to  turn  round  and  move  their  cilia  freely 
therein,  which  they  are  continually  doing.  The  primaiy  cell  of  Cldamydo- 
coccus,  like  that  of  Eudorina,  divides  up  into  2,  4,  8,  or  16  cells,  and  those  of 
the  eight-  and  sixteen- divisions  again  into  groups  of  16  or  32  each,  so  as  to 
resemble  the  third  stage  of  Eudorina.  Hence  we  may  perhaps  infer  that  its 
fecundating  process  is  similar  to  that  of  Eudorina ;  but  this  remains  to  be 
discovered.  Chlamydococcus  has  also  a  great  tendency  to  stop  at  the  two- 
and  four- division,  from  which  it  may  pass  into  the  '  still '  or  Protococcus-ioYm.^ 
and,  floating  on  the  water  in  a  kind  of  cnist,  present  cells  of  all  kinds  of  sizes 
undergoing  '  still '  division.  In  all  its  multiplications,  partial  and  entire, 
however,  it  generally  maintains  its  primary  or  spherical  form,  and  does  not 
become  ovoid  or  oblong,  like  the  groups  of  Eudorina,  the  only  exceptions 
being  in  the  two-  and  foui'-division,  w^here  the  green  cells  are  sometimes 
ovate  (probably  from  want  of  room  in  the  parent  capsule),  as  represented  by 
Ehrenberg  in  C.  Pulvisculus, — to  which  I  should  refer  it,  had  he  not  also 
given  an  ovate  form  to  the  type-cell  of  this  species  ;  nor  can  I  refer  it  to  C. 
pluvialis,  for  in  all  the  changes  I  have  yet  seen  it  undergo,  the  red  colour  has 
not  increased  beyond  the  minute  eye-spot,  while  this  also  disappears,  and  the 
cilia  too,  when  this  species  passes  into  the  '  still '  form.  Here  it  undergoes 
the  same  kind  of  division  that  it  does  in  the  active  state  ;  but  the  parent- 
cell,  instead  of  becoming  distended  by  imbibition,  remains  closely  attached  to 
the  daughter-cells,  so  as  to  give  the  group  a  mulberiy  shape.  How  long  it 
remains  in  the  '  still '  form  I  am  ignorant ;  but  having  only  seen  it  in  the 
a<itive  state  dui^ing  the  months  of  May,  June,  and  August,  and  thi^oughout  the 
rest  of  the  year  in  the  '  still '  one,  I  am  inclined  to  think  that  it  only  comes 
into  the  active  state  during  the  summer  months,  and  then  for  the  purpose  of 
fecundation. 

"  In  several  instances,  also,  where  I  have  found  this  Chlamydococcus  with 
Eudorina,  they  have  been  accompanied  by  long  Closteriform  cells.  It  was 
the  case  in  that  above  mentioned,  where  the  latter  was  imdergoing  impreg- 
nation. Some  of  these  have  an  eye-spot,  which,  with  the  nature,  arrange- 
ment, and  general  aspect  of  their  internal  contents,  show  that  they  belong  to 
the  class  of  organisms  with  which  they  are  associated.  Their  cell- wall  also 
is  more  or  less  plastic,  or  was  so  when  they  were  assuming  this  spicular  form ; 
for  many  have  one  or  more  diverticula  extending  from  them,  some  are  bifid, 
and  a  few  irregularly  steUate.  What  they  are  I  know  not ;  but  Dr.  Cohn 
has  figured  the  same  kind  of  cells,  in  company  with  SphoiropJea  anmdina, 
under  impregnation." 

StephanoaphaTa. — To  Dr.  Ferdinand  Cohn,  to  whom  science  is  so  deeply 


OF  THE  PHYTOZOA.  165 

indebted  for  his  researches  among  the  simplest  organisms  of  creation,  additional 
thanks  are  due  for  the  elaborate  essay  on  a  new  genus  of  Volvodnece,  in 
which  he  has  most  philosophically  displayed  the  stmcture  and  relations  of 
that  family  at  large.  The  new  genus  is  named  by  him  Stepliaiiosphcera,  the 
structui-al  and  physiological  characters  of  which  have  been  presented  to  the 
English  reader  by  an  excellent  translation  of  Cohn's  original  paper,  in  the 
A.  N.  H.  1852,  X.  p.  321  et  seq.  Besides  this  account  of  Stephanosphcera 
by  its  discoverer,  none  other  exists  ;  we  must  accordingly  make  extensive  use 
of  it  in  attempting  an  abridged  description, — a  difficult  task  on  account  of  the 
importance  of  almost  eveiy  paragraph  it  contains. 

The  organisms  to  be  described  *'  exhibit  an  extraordinary  variety  of  size  and 
shape,"  writes  Cohn  ;  "  but  they  are  aU  essentially  of  similar  structure,  and 
consist  of  eight  green  spherical  corpuscles  having  their  central  points  situated  at 
the  circumference  of  a  circle  (XIX.  38),  and  of  a  large  common  envelope,  en- 
closing the  former  as  a  colourless  vesicle,  at  the  equator  of  which  are  ranged 
the  said  eight  green  globules  (XIX.  40-58). 

"  The  common  envelope  is  boimded  by  a  membrane  whoUy  devoid  of  struc- 
tui-e  and  transparent,  so  that  it  may  be  overlooked  if  the  illumination  be  not 
properly  modified,  under  which  circumstances  the  8  green  globules  appear 
destitute  of  any  common  bond  of  union.  But  the  membrane  of  the  envelope 
always  exists ;  and  although  very  delicate  and  thin  while  young  (XIX.  57-58), 
it  becomes  thickened  with  age,  and  then  possesses  an  evident  breadth,  albeit 
no  compound  structure  can  be  detected.  The  membrane  of  the  envelope  is  ab- 
solutely rigid,  and  never  changes  its  shape,  excepting  through  the  ordinary 
expansion  of  growth  ;  therefore  it  is  not  only  totally  devoid  of  contractility, 
but  is  even  elastic  only  in  a  slight  degree. 

"  In  whatever  dii'ection  the  total  organism  may  lie  during  its  movements, 
the  envelope  always  appears  as  a  perfect,  absolutely  regular  circle  (XIX.  38, 
39) ;  thence  it  results  most  decidedly  that  the  membrane  of  the  envelope  forms 
a  sphere  which  may  perhaps  deviate  but  very  little  from  the  mathematical 
ideal.  The  diameter  of  the  envelope  varies  between  tolerably  wide  limits : 
while  some  younger  forms  possess  an  envelope  ^th  of  a  line  (0*028  mm.)  in 
diameter,  most  attain  one  of  -g^j-th  (0-044  mm.),  and  the  largest  are  as  much 
as  ^th  of  a  line  (0-055  mm.)  in  diameter. 

"  The  phgenomena  in  dissolution  and  duiing  propagation  prove  that  the 
membrane  of  the  envelope  immediately  surrounds  a  colourless  watery  fluid, 
the  refractive  power  of  which  does  not  dififer  from  that  of  water.  The  enve- 
lope may  therefore  be  regarded  as  a  broad  spherical  cell  with  a  delicate  strac- 
tiu-eless  membrane,  colouiiess  and  transparent  like  glass,  containing  a  thin, 
water-like,  colouiiess  fluid ;  consequently  I  shall  denominate  it  the  envelope- 
cell  {Hull-zelle). 

"  "WTiile  the  envelope-cell  varies,  generally  speaking,  only  in  size,  and  no 
difference  whatever  of  shape  and  stnicture  can  be  detected  in  the  different 
individuals,  the  variations  in  the  development  of  the  eight  green  globes  in  its 
interior  are  very  great.  In  fact  it  is  difficult  to  represent  the  multipHcity  of 
forms  which  here  display  themselves,  so  as  to  give  a  full  and  clear  idea 
of  them;  and  our  figm^es  even  can  aff'ord  but  a  very  insufficient  picture, 
since  scarcely  a  single  individual  exactly  resembles  another  in  this  respect. 
The  eight  green  bodies  in  the  interior  of  each  envelope-ceU,  which,  for  reasons 
to  be  given  hereafter,  I  shall  call  primordial  cells,  are  in  their  simplest 
condition  globular,  and  stand  at  equal  distances  in  a  cii^cle  at  the  largest 
cii'cumference  of  the  envelope-cell,  so  that  the  whole  stnicture  looks  like  a 
hollow  glass  globe  with  a  ring  formed  of  eight  green  globules  in  its  interior 
(XIX.  38).     If  the  circular  line  in  which  the  centres  of  the  eight  primordial 


166  GENERAL  HISTORY  OF  THE  INFUSORIA. 

cells  stand,  is  regarded  as  the  equator  of  the  envelope-cell,  we  ordinarily 
find  their  position  such  that  the  equatorial  zone  lies  parallel  with  the  plane 
of  the  object-glass,  and  the  observer  consequently  looks  down  upon  the  pole 
of  the  envelope-cell.  In  this,  the  jpolar  view,  the  eight  primordial  cells 
stand  in  a  perfect  cii'cle  and  are  placed  very  close  to  the  circumference  of  the 
envelope-cell.  The  distances  between  the  primordial  cells  are  more  or  less 
considerable  according  as  they  are  proportionately  larger  or  smaller ;  some- 
times they  constitute  an  elegant  wreath  composed  of  eight  large  green  rosettes, 
almost  without  any  intervals  between  them,  or  resemble  an  interrupted  eight- 
angled  star ;  sometimes  the  green  globules  are  so  far  apart  as  to  look  like  the 
eight  spokes  of  a  wheel.  The  diameter  of  a  primordial  cell  in  the  polar  view 
amounts  in  the  former  case  to  y^th  of  a  line  (0-012  mm.),  in  the  latter  to 
^th  (0-0065),— on  an  average  to  ^th  of  a  line  (0-0087  mm.). 

"  When,  however,  the  whole  revolves,  so  that  the  axis  passing  through  the 
two  poles  of  the  envelope-cell  lies  parallel  with  the  stage  of  the  microscope, 
and  the  equatorial  zone  marked  by  the  eight  green  primordial  cells  stands 
perpendicular  to  the  latter,  consequently  in  the  optic  axis  of  the  microscope, 
the  envelope-cell  still  looks  like  a  circle,  because  it  is  a  sphere  ;  but  the  eight 
primordial  coUs,  lying  in  one  plane,  are  then  projected  in  a  line  which  corre- 
sponds to  the  diameter  of  this  circle,  so  that  the  whole  resembles,  under  the 
microscope,  a  colourless  disk  cut  in  half  by  a  green  zone  (XIX.  40-58).  And 
in  this,  the  eqaatorial  view,  according  to  the  position,  the  foiu'  primordial 
cells  in  the  anterior  hemisphere  sometimes  completely  cover  the  four  behind, 
so  that  only  four  are  seen  altogether ;  sometimes  the  latter  appear  through 
the  interspaces  between  the  former,  and  all  eight  are  seen  in  one  line.  This 
view  also,  of  course,  gives  very  different  pictures  according  to  the  size  of  the 
primordial  cells  and  the  distance  between  them. 

"  Between  the  polar  and  equatorial  views  lie  countless  intermediate  posi- 
tions in  which  the  ring  of  primordial  cells,  more  or  less  contracted,  appears 
as  an  ellipse,  with  its  longest  axis  constantly  in  the  diameter  of  the  envelope- 
cell,  while  the  shorter  axis  appears  longer  or  shorter,  and  the  separate  pri- 
mordial cells  are  approached  more  or  less  towards  each  other,  according  to  the 
laws  of  projection. 

*'  Besides  this  diiference  of  the  aspect  Avhich  one  and  the  same  individual 
affords  merely  in  consequence  of  the  different  i^ositions  resulting  from  its 
movements,  a  still  greater  variation  is  displayed  in  the  sha2:)e  of  the  green 
primordial  cells  themselves.  1  have  called  them  globes  above ;  properly  they 
are  always  acuminated  to  some  extent,  in  the  form  of  a  pear,  toward  the 
periphery  of  the  envelope-cell ;  and  they  are  imperceptibly  attenuated  to  a 
point  here,  from  which  two  cilia  pass  out  (XIX.  38).  These  cilia  therefore 
arise  from  the  primordial  cells  inside  the  envelope-cell,  and  they  emerge  freely 
into  the  water  through  minute  orifices  in  the  latter :  from  the  analogy  with 
Chlamydococcus,  I  conjecture  that  there  is  a  separate  passage  for  each  cilium, 
so  that  the  orifices  corresponding  in  each  case  to  the  primordial  cells  are 
placed  in  pairs,  and  all  sixteen  orifices  occur  in  the  equator  of  the  envelope- 
cell.  Hence  in  the  polar  view  the  eight  pairs  of  cilia  go  out  from  the  cii'cum- 
fcrence  of  the  envelope-ceU  like  elongated  rays. 

"  The  primordial  cells  moreover  expand  principally  in  the  direction  of  ike 
axis  perpendicular  to  the  equatorial  plane,  so  that  in  the  equatorial  view  they 
appear  not  spherical,  but  rather  elliptical,  or  even  sometimes  stretched  so 
considerably  in  this  direction,  that  they  become  cylindi-ical  or  almost  spindle- 
shaped,  without  undergomg  any  remarkable  enlargement  on  the  other  axis. 
If  in  this  case  the  primordial  cells  are  large  and  near  together,  they  form 
in  the  equatorial  view  a  broad  green  zone  inside  the  colomless  envelope- 


OF  THE  PHYTOZOA.  167 

cell,  filling  up  a  more  or  less  considerable  portion  of  this  (XIX.  39),  while  in 
the  polar  view  they  form  only  a  circular  wreath.  In  some  instances  the 
proper  green  body  of  the  primordial  cells  is  only  shortly  cylindrical ;  but  it 
becomes  elongated  at  both  ends  into  long  beaks  which  reach  almost  to  the 
poles,  and  give  each  primordial  cell  something  of  the  shape  of  the  Closterium 
setaceum  figui^cd  by  Ehrenberg.  In  this  case  the  whole  resembles  a  sphere 
suiTounded  by  eight  green  bands  placed  in  meridians  and  swollen  only  in  the 
equatorial  region.  But  even  in  this  veiy  frequently  occuiTing  preponderating 
development  of  the  one  dimension,  the  cilia  of  each  primordial  cell  are  sent 
out  from  the  middle  of  its  shorter  axis ;  and  when  the  primordial  cells  appear 
projected  in  a  zone,  in  the  equatorial  view,  the  motile  cilia  are  visible  only  at 
four  points  of  the  diameter. 

"  The  primordial  cells  are  very  frequently  developed  unequally  in  the  two 
hemispheres  of  the  envelope-cell ;  they  are  not  then  divided  into  two  equal 
halves  by  the  equator  of  the  envelope -cell,  but  show  themselves  crowded 
principally  into  one  hemisphere,  which  they  almost  fill ;  and  they  reach  almost 
to  the  pole  there,  while  they  occupy  but  a  far  smaller  portion  of  the  other, 
which  consequently  appears  in  greater  paii:  colouiless.  In  such  a  case  the 
primordial  cells  almost  touch  with  one  end,  while  they  diverge  widely  at  the 
other,  and  thus  they  look  like  a  kind  of  basket  composed  of  eight  pieces,  like 
the  gaping  dental  apparatus  of  a  Chilodon. 

•'  Besides  the  two  cilia  which  pass  out  from  each  primordial  cell,  through 
the  orifices  of  the  envelope-cell  into  the  water,  the  former  very  frequently 
send  out  other  prolongations,  which  however  do  not  perforate  the  envelope- 
cell.  These  are  colourless  mucilaginous  Jilaments,  going  out  from  each  pri- 
mordial cell,  especially  from  the  ends  of  their  longer  axis,  and  which  hence 
present  themselves  especially  clearly  in  the  equatorial  view.  The  ends  of  the 
primordial  cells  are  mostly  not  green  but  colourless,  and  elongated  into  numer- 
ous, likewise  colourless,  broader  or  thinner  bristle-like  processes,  which  run  out 
like  rays  in  all  directions,  are  often  ramified,  and  are  attached  to  the  inside  of 
the  envelope-cell,  without  however  perforating  it  (XIX.  39).  If  these  fila- 
ments are  much  developed,  they  form  a  proper  network,  w^hich  maiataitis  each 
primordial  cell  floating  in  the  common  envelope.  The  extremities  of  the  pri- 
mordial cells  are  also  frequently  divided  dichotomously  into  colourless  muci- 
laginous bands,  which  again  branch  into  radiating  filaments  and  thus  produce 
the  most  wonderful  forms.  These  colourless  filiform  prolongations  of  the 
primordial  cells  may  also  be  seen  in  the  polar  view,  stretching  in  aU  direc- 
tions, and  giving  the  total  structui^e  a  most  strange  aspect,  almost  similar  to 
that  of  a  Xanthidium. 

"  In  the  internal  organization  of  the  primordial  cells,  all  that  can  be  made 
out  is  a  green-coloured  softish  substance,  of  which  they  are  composed,  and  in 
which  numerous  delicate  granules  or  points  are  imbedded.  "Wlien  the  pri- 
mordial cells  are  actively  vegetating,  they  are  of  a  transparent  vivid  green ; 
but  the  coloiu'  exhibits  various  tints :  in  the  youngest  conditions  it  is  purer, 
more  yellowish  green,  less  obscured  by  dark  points  ;  in  the  largest  forms,  on 
the  contrary,  the  contents  appear  brownish  green  and  opake,  with  the  dark 
granules  multiphed  to  such  an  extent,  that  the  whole  almost  loses  its  transpa- 
rency. In  the  middle  of  the  primordial  cells  are  found  tiuo  larger,  nucleus-UTce 
vesicles,  mostly  symmetrically  placed ;  and  these  examined  separately  appear 
annular,  so  that  tliey  possess  an  internal  cavity  ;  iodine  colours  them  remarkably 
dark,  with  a  ^dolet  tinge  (XIX.  39).  The  centre  of  each  primordial  cell  is 
frequently  occupied  by  a  lighter  circular  space,  which  however  does  not  vanish 
periodically,  and  therefore  cannot  be  regarded  as  a  contractile  vesicle  (XIX.  38). 

"  The  primordial  cells  are  not  surrounded  by  any  special  rigid  membrane; 


168  GENERAL  HISTOEY  OF  THE  INTUSORIA. 

and  this  is  not  only  made  evident  by  the  multifold  changes  of  form  which  they 
undergo  in  the  course  of  vegetation,  and  by  the  filiform  prolongations  and 
ramifications  which  are  produced  directly  from  their  substance,  but  is  clearly 
shown  by  the  transformations  which  the  primordial  cells  pass  through  in  con- 
sequence of  external  influences.  Under  certain  circumstances,  namely,  the 
filiform  processes  may  be  retracted,  being  torn  away  from  the  envelope-cell 
and  taken  up  into  the  substance  of  the  primordial  cells ;  the  produced  ends 
of  the  primordial  cells  also  disappear,  the  latter  becoming  rounded  off  into 
their  original  spherical  or  short -cylindrical  form.  Such  a  change  would  be 
impossible  if  the  primordial  cells  were  surrounded  by  a  rigid  membrane,  such 
as  that  of  the  envehpe-cell  for  example.  Still  more  rapid  and  decided  are  the 
metamorphoses  which  the  primordial  cells  undergo  in  the  interior  of  the 
envelope -cell,  through  influences  destructive  to  the  life  of  the  organism. 
These  phsenomena,  usually  called  dissolution,  do  not  change  the  rigid  enve- 
lope-cell at  all ;  but  they  totally  decompose  the  primordial  cells,  depriving 
them  of  their  form  and  dissolving  them  into  a  single  structureless  green  mass, 
which  lies  upon  the  inside  of  the  envelope-cell,  frequently  destroying  all  e^d- 
dence  of  the  origin  from  eight  spheres,  while  not  a  trace  of  special  enveloping 
membranes  comes  to  light.  These  phsenomena  of  dissolution  moreover  indicate 
that  the  envelope-cell,  as  I  have  already  mentioned,  is  composed  of  a  delicate 
memhrane  encloshig  a  clear  watery  fluid,  which  cannot  be  dense,  gelatinous,  or 
mucilaginous,  since  it  is  readily  displaced  by  the  radiating  filaments  and  the 
dissolved  substance,  and  which  therefore  is  very  similar  to  pure  water,  if  not 
exactly  the  same. 

"  Motion. — The  cilia  which  are  protruded  from  the  equator  of  the  envelope- 
cell  are  but  short  inside  this  ;  but  the  portion  projecting  into  the  water  is  much 
longer  and  vibrates  actively,  thereby  causing  all  the  movements.  During 
therr  vibration  the  cilia  are  difiicult  to  detect ;  but  when  dried  on  glass,  and 
still  better  by  wetting  them  with  iodine,  they  may  readily  be  traced  in  their 
whole  length,  especially  if  sulphuric  acid  is  added,  this  rendering  them  more 
distinct  and  giving  them  a  darker  coloiu\  The  motion  of  the  entire  organism, 
depending  on  the  eight  pairs  of  cilia,  exactly  resembles  that  well  known  in 
the  Algae  and  many  Infusoria.  First  there  is  a  rapid  revolution  round  that 
axis  of  the  envelope-cell  wliich  passes  through  its  poles  and  stands  perpen- 
dicular to  the  ring  of  primordial  cells,  so  that  the  envelope-cell  rotates  like  a 
wheel  upon  its  axle.  In  the  polar  view  (XIX.  38),  our  form  gives  exactly 
the  impression  of  a  revolving  wheel,  while  in  the  equatorial  view  (XIX.  39), 
where  the  primordial  cells  are  mostly  elongated,  it  has  more  the  aspect  of  a 
globe  turning  upon  its  axis.  Besides  this  revolution  on  its  axis,  which  endui'es 
throughout  the  whole  life,  there  is  an  advancing  movement,  which  produces 
a  very  irregular  course  ;  in  this  way  these  organisms  screw  themselves,  as  it 
were,  onwards  in  the  water.  Sometimes  they  swim  straight  out  with  uniform 
rapidity,  the  pole  going  first,  the  rotating  ring  of  primordial  cells  standing  at 
right  angles  to  the  coui'se  and  appearing  only  in  one  line  ;  sometimes  they 
turn  round,  so  that  the  equatorial  plane  presents  itself  as  a  circle  again  (in 
the  polar  view) :  they  rotate  thus  round  their  centre  without  moving  from 
the  spot ;  then  they  set  one  pole  forward  and  swim  on  in  another  dii-ection, 
bend  to  the  light  or  to  the  left,  or  turn  quite  round,  mostly  -wdthout  any  per- 
ceptible obstniction,  move  in  curves  of  the  most  vaiied  kinds,  run  round  any 
point  in  spiral  lines,  come  into  different  planes,  sometimes  ascending,  some- 
times descending ;  in  short,  they  exhibit  aU  those  most  complex  and  wonderful 
dhsenomena  of  locomotion  which  we  are  acquainted  with  in  the  mo\'ing  propaga- 
tive  cells  of  the  Algae, — and,  as  I  have  demonstrated  elsewhere,  in  exactly  the 
same  vjay  in  the  Astomous  and  Anenterous  Infusoria  (Monadina,  Asiasioia, 


OF  THE  PHTTOZOA.  169 

Cniptomonadina,  kc),  and  which  certainly  do  not  bear  at  all  the  character  of 
piu'posing,  conscious  volition,  but  appear  as  an  activity  determined  not  indeed 
by  pui-ely  external  causes,  but  by  internal  causes  in  the  organization  and  vital 
process.  The  collective  idea  of  such  motions  is  best  represented  by  the  coui'se 
described  by  a  top  which  runs  thi^ough  the  most  varied  cui'ves  while  at  the 
same  time  constantly  revohing  on  its  axis. 

"  Although  Alex.  Braim  describes  a  constant  revolution  to  the  left  in  the 
in  many  respects  analogous  swarming- cells  of  Chlamydococcus  and  the  swarm- 
ing-spores  of  (Edogonium,  and  to  the  right  in  the  moving  gonidia  of  Vaiicheria 
and  the  families  of  Pandorina,  I  must  assert  that  no  such  constant  Jaw  of  re- 
volution exists  in  the  structure  here  described. 

"As  to  its  systematic  position. — It  is  evident  that  the  organism  tve  have 
described  belongs  to  the  family  of  the  Volvocinew.  For  not  only  do  we  find  in 
it  the  two  principal  characters  which  are  characteristic  of  this  interesting 
family — the  presence  of  a  number  of  green  globes  which,  enclosed  in  a 
common  coloiuiess  envelope,  represent  a  family  of  cells  (polypidom),  together 
with  the  constant  rolling  motion  which  the  Volvocinece  possess  through 
almost  the  whole  of  their  life, — but  oui'  form  also  displays,  as  Ave  shall  see 
hereafter,  the  thii^d  character  of  the  Volvocinece,  that  the  separate  globes  propa- 
gate within  the  envelope.  In  fact,  there  exist  the  greatest  analogies  between 
the  knoA\Ti  genera  of  Volvocinece,  especially  Gonium  and  Pandorina,  and  the 
organism  here  described ;  and  these  genera  are  only  essentially  distinguished 
by  the  aiTangement  of  the  green  globes  or  primordial  cells,  which  in  Pando- 
rimi  are  placed  on  a  spherical  surface,  in  Goyiium  on  a  flat  plane,  while  in 
our  form  they  stand  at  the  cii'cumference  of  a  circle.  Since,  however,  this 
very  law  of  arrangement  is,  in  the  family  of  the  Volvocinece,  the  most  im- 
portant criterion  on  which  the  establishment  of  the  genera  depends,  it  follows 
that  we  here  have  a  peculiar  genus  which  I  do  not  find  described  either  in 
Ehrenberg's  great  work  or  in  any  later  publication. 

"  If  we  now  compare  the  conditions  of  organization  of  Stephanosphcera 
Arith  those  of  Chlamydococcus,  we  find  the  most  essential  agreement.  In  the 
fii'st  place  the  envelope-cell  of  Stephanosphcera  corresponds  exactly  to  that  of 
the  moving  macrogonidia  of  Chlamydococcus ;  it  is  composed  of  a  delicate 
colourless  membrane  and  contents  resembling  water.  Chemical  actions  to 
which  I  subjected  the  envelope- cell  of  Stephanosphcera,  bear  Avitness  of  tliis 
agreement  in  the  most  minute  particulars.  The  envelope-cell  is  indiflferent 
to  acids  and  alkahes  and  is  not  dissolved  in  them ;  but  it  suffers  a  peculiar 
thickening  by  sulphuiic  acid,  which  causes  it  to  apply  itself  more  closely  to 
the  primordial  cell,  and  present  itself  very  distinctly  and  clearly  defined.  In 
general  the  application  of  dilute  sulphuric  acid  is  often  the  best  means  of 
making  clear  delicate  vegetable  membranes  wliich  would  otherAAise  be  readily 
overlooked,  especially  Avhen  iodine  is  added,  Avhich  then  ordinarily  colours  the 
membrane  yellow.  The  cilia  also  are  rendered  more  distinct  by  sulphuric 
acid.  The  envelope-cells  of  Pandorina,  Chlamydococcus,  and  Volvox  behaA'e 
in  exactly  the  same  Avay. 

"  AVith  regard  to  the  chemical  composition  of  the  envelope-cell  of  Stepha- 
nosphaTa,  I  have  succeeded  in  demonstrating  the  characteristic  reaction  of 
vegetable  celhdose,  the  blue  colouring  by  iodine  and  sulphuric  acid,  in  the  enve- 
lope-cell of  Stephanospha^ra.  For  this  piu'pose  it  is  requisite  to  aUoAV  a  drop 
oi pretty  concentrated  sulphuric  acid  to  act  upon  the  swarming  Stephanosphcera- 
globes  imtil  the  green  primordial  cells  in  the  interior  are  decomposed, — by 
wliich  time  the  proper  transformation  of  the  envelope-membrane  has  taken 
place,  and  a  drop  of  solution  of  iodine  (iodine  in  iodide  of  potassium),  suffi- 
ciently diluted  to  prevent  the  sulphuric  acid  precipitating  it  in  crystals,  then 


170  GENERAL  HISTORY  OF  THE  INFUSORIA. 

produces  a  coloration  of  the  envelope,  -which  appears  at  first  violet,  gradually 
becoming  moi'e  intense,  and  at  last  heautifid  indigo-blue.  xThus  the  chemical 
beha\^our  of  the  envelope-cell  in  Stej)hanosj)ha?ra,  as  in  Chlamydococcus,  is 
the  most  evident  proof  that  the  organisms  to  which  they  belong  cannot  be 
regarded  as  Infusoria,  but  are  simply  Algae.  Moreover  this  behaviour  of  the 
envelope- cell  of  Stejyhanosjyhcera  shows  that  the  latter  is  bounded  by  a  tiTie 
cellulose  membrane,  and  not,  as  is  assumed  almost  universally  of  the  Volvo - 
cineoe,  and  by  Niigeli  even  of  all  Algae,  of  secreted  mucus  or  jelly.  The  direct 
observation  of  the  envelope-cell  of  Steplianosjylicera  like"^ise  shows  that  this 
is  completely  closed  in  its  normal  condition,  and  only  perforated  by  oiifices 
in  the  spots  where  the  cilia  of  each  primordial  cell  pass  out.  Not  until  a 
later  stage,  when  the  primordial  cells  singly  leave  the  envelope  or  have  begun 
to  propagate,  does  the  membrane  of  the  envelope  tear,  gradually  collapse,  and 
become  dissolved,  so  that  the  included  globes  can  make  their  exit  freely. 

''  It  is  obvious  that  the  eight  green  globes  of  Steplianosplioira  correspond 
exactly  to  the  primordial  cell  of  Chlamydococcus.  The  primordial  cells  of 
StephanosphcBra  consist  in  like  manner  of  nitrogenous  protoplasm,  in  itself 
coloiuiess,  which  is  coloured  brown  by  iodine  and  almost  wholly  dissolved  by 
caustic  potash  and  ammonia.  The  protoplasm  is  coloured  by  the  universal 
colouring  matter  of  vegetables,  chlorophyll ;  for  alcohol  and  aether  bleach  the 
green  globules,  and  concentrated  sulphuric  acid  changes  the  green  colour  into 
a  verdigris-green  or  blue, — a  reaction  which,  from  my  observations,  is  cha- 
racteristic of  chlorophyll. 

"  The  chemical  nature  of  the  fine  granules  in  the  primordial  cells,  which 
with  age  multiply  so  that  the  primordial  cells  at  length  lose  their  transparent 
green  colour  and  appear  dull,  opake,  and  olive -brown,  is  difficult  to  deter- 
mine on  account  of  theii'  small  size ;  they  are  either  protoplasm-granules, 
or,  as  a  bluish  colour  given  by  iodine  might  leave  one  to  conclude,  perhaps 
starch-granules.  On  the  other  hand,  the  two  darher  nuclei  in  each  pri- 
mordial cell  are  undoubtedly  the  same  stnictm^es  which  occur  in  Chlamy- 
dococcus and,  in  like  manner,  not  only  in  all  the  Volvocinece,  but  also  in  most 
of  the  Algae  of  the  orders  of  Palmellece,  Desmidece,  Gonfervece,  &c.  IN'ageli 
has  called  these  chlorophyll-utricles,  and  demonstrated  their  universal  occur- 
rence in  the  vegetable  kingdom  by  comparative  descriptions  (Gattung.  einzell. 
Alg.  ii.).  Ordinarily  there  exist  only  two  in  Stephanosphoira,  which  may 
be  distinguished  in  the  earliest  stages, — while,  among  other  Volvocinece,  for 
instance,  Gonium  contains  only  one  chlorophyll-utricle.  It  is  difficult  to  settle 
anything  definite  concerning  theii'  structure  and  function ;  they  must  not  be 
regarded  as  ceU-nuclei,  although  they  resemble  them  very  much,  especially 
when  only  one  is  present.  Caustic  potash,  which  destroys  the  rest  of  the 
contents  of  the  primordial-cells,  makes  the  chlorophyll  utricles  of  Stepha- 
nosphoira show  themselves  more  distinctly  as  hollow  rings,  surrounded  by  a 
membrane  which  is  rather  granular ;  iodine  colours  them  deep  violet,  which 
leads  to  the  conclusion  of  the  presence  of  starch.  Ehrenberg  thought  the 
chlorophyll-utricles  were  to  be  recognized  as  the  testes  of  the  Volvocinece ;  it 
is  certain,  however,  that  these  structui-es  may  be  seen  in  greater  or  less 
number,  in  exactly  the  same  way,  in  undeniable  plants,  such  as  HydrocUc- 
tyon,  (Edogonium,  Mougeotia,  and  others. 

^'  I  have  already  shown  that  the  primordial  cells  of  Stephanosphcera  as  well 
as  those  of  Chlamydococcus  are  destitute  of  a  special  rigid  membrane ;  con- 
sequently they  do  not  correspond  to  perfect  cells,  but  on  the  whole  only  to 
primordial  utricles.  In  like  manner  the  cmious  colourless  mucous  filaments 
which  extend  out  from  the  extremities  of  the  primordial  cells  of  Stepha- 
nosphcera are  evidently  analogous  to  the  rays  which  make  one  condition  of 


OF  THE  PHTTOZOA.  171 

the  Chhnii/dococcus-ce]ls  look  hairy  (var.  setiger,  V.  Flotow).  They  are 
merely  prolongations  of  the  colourless  protoplasm  forming  the  substance  of 
the  primordial  cells,  and  correspond  pretty  well  morphologically  to  the  reticu- 
lated branching  filaments  of  protoplasm,  the  sap-currents  as  they  are  termed, 
which  maintain  the  nucleus  suspended  freely  in  the  interior  of  the  cells  of 
the  articulations  of  Spirogyra  or  of  the  haii's  of  the  anthers  of  Tradescantia. 
Alcohol  and  acids  cause  these  prolongations  to  be  retracted  into  the  substance 
of  the  primordial  cells ;  the  same  thing  takes  place  diu'ing  the  coiu'se  of  the 
development.  Ehi^enberg  has  called  these  peculiar  mucous  rays,  which  also 
occur  in  some  other  Volvocinece,  in  some  cases  a  tail  (Sgnura,  Uroglena),  in 
others  connecting  canals  or  indications  of  a  vascular  system  (in  Volvox  and 
Gonium).  These  protoplasm-iilaments  naturally  present  a  different  aspect 
according  to  the  shape  and  arrangement  of  the  primordial  ceUs :  wliile  they 
appear  as  a  wreath  of  cilia  in  the  globular  Chlamydococcus-eeH,  in  the  more 
spincUe-shaped  Stephanosphcera  they  rather  resemble  bundles  of  rays  passing 
out  fi'om  each  end ;  in  Volvox,  if  seen  only  from  above,  they  give  the  indi- 
vidual primordial  cells  a  polygonal,  radiating  aspect,  and  form  threads  of 
communication  between  them :  Focke  has  wrongly  considered  them  as  inter- 
cellular passages  between  the  individual  animalcules.  The  connecting  threads 
in  Gonium,  on  the  other  hand,  are  something  quite  different,  and  do  not  belong 
at  all  to  the  domain  of  the  j)rotoplasm-filaments,  as  I  shall  explain  more  fully 
at  another  opportunity. 

"  Thus  the  microscopic  analysis,  like  the  chemical  investigation,  of  Steplia- 
nosplicera,  in  exact  analogy  mth  Chlamydococcus  and  the  swarming- cells  of 
the  other  Alga3,  has  enabled  us  to  distinguish  aU  the  characters  of  a  plant, 
but  not  one  mark  of  a  true  animal  organization,  in  particular  not  a  trace  of  a 
mouth,  stomach,  and  sexual  organs.  But  the  genus  Steplianosphcera  is  thereby 
pre-eminently  important  for  the  decision  of  the  question  of  the  limit  between 
the  animal  and  vegetable  kingdom,  because  the  history  of  its  development  affords 
the  most  convincing  proof  of  the  vegetable  nature  of  this  genus,  and  thus  of  all 
the  other  Yolvocinese. 

"  Development  of  Stephanosphcera. — Both  the  very  delicate  envelope-cell 
and  the  widely  distant,  transparent,  green,  globular,  primordial  cells  of  the 
young  Stephanosphcera  are  of  a  relatively  small  size.  Both  grow  so  much  as 
to  double  their  dimensions  dimng  their  vegetation :  the  former  acquii-es  a 
tough  membrane;  the  latter  fill  up  the  greater  part  of  the  envelope- ceU, 
advance  towards  each  other  so  as  to  touch,  develope  thicker,  denser  contents, 
and  assume  most  curious  forms  through  the  ramification  of  the  protoplasm- 
filaments.  FinaUy  the  process  of  propagation  shows  itself  in  the  primordial 
cells.  The  radiating  ends  retract  aU  theii'  prolongations,  and  become  rounded 
into  a  perfect  sphere ;  the  primordial  cells  are  now  merely  attached  to  the 
envelope-ceU  by  theii-  cilia,  and  thus  are  readily  moved  from  their  normal 
corresponding  positions,  and  then  appear  devoid  of  any  definite  arrangement 
in  the  envelope- ceU. 

'^  These  changes  take  place  in  the  com-se  of  the  afternoon  ;  towards  evening 
more  influential  metamorphoses  make  their  appearance.  The  primordial  cell, 
namely,  extends  itself  predominantly  in  one  direction  in  the  axis  perpendicular 
to  the  equatorial  plane,  consequently  in  the  position  wliich  represents  from 
above  dovvnwards.  The  two  chlorophyll-utricles  respectively  repair  to  the 
two  ends ;  the  green  contents  likewise  flow  chiefly  to  the  two  sides,  and  leave 
a  broad  colomless  zone  visible  in  the  middle,  such  as  we  observe  somewhat  in 
the  same  position  in  Closferium.  Finally  the  primordial  cell  becomes  con- 
stricted, gradually  from  the  periphery  to  the  centre,  in  the  middle  line,  and 
is  thus  divided  into  two  secondary  cells,  the  septum  of  which,  in  the  position 


172  GENERAL  HISTORY  OF  THE  IXPUSORIA. 

above  assumed,  runs  from  right  to  left.  Each  of  the  halves  cut  off  by  the 
division  then  exj)ands  somewhat  in  the  direction  from  left  to  right ;  a  new 
constriction  soon  presents  itself  in  the  direction  from  above  downwards; 
when  this  is  complete,  the  originally  globular  primordial  cell  is  divided  into 
foui'  quarters  (XIX.  40). 

''  This  process  of  constriction  and  cutting  oif  is  repeated  once  more,  each 
secondary  cell  becoming  divided  by  a  new  septum  into  two  equal  halves 
(XIX.  41-56). 

"  This  process  of  division,  by  which  each  primordial  cell  produces  in  the 
first  generation  two,  in  the  second  foui',  and  in  the  third  eight  secondary  cells, 
is  completed  in  the  course  of  the  night,  so  that  early  in  the  morning,  in  the 
long  summer  days  even  by  3  o'clock,  we  perceive  each  of  the  eight  primordial 
cells  divided  into  eight  in  the  manner  described  (XIX.  41,  42).  The  gene- 
rations produced  in  each  case  by  this  triple  subdivision  vary  in  the  duration 
of  their  lives  and  in  their  capacity  of  development ;  the  first  two  rapidly 
divide  again,  and  therefore  are,  according  to  Xiigeli's  expression,  mere 
'  transitional  generations ; '  the  third  alone  arrive  at  complete  development 
and  persist  a  long  time  as  such  ;  these  form  the  'permanent  generation,^ 

*'  The  process  of  division  does  not  always  take  place  simultaneously  in  all 
the  eight  primordial  cells  of  Steplianosjyhcera ;  we  not  unfrequently  find  inside 
the  same  envelope- cell  some  primordial  cells  still  wholly  unaltered,  Avhile 
others  are  already  preparing  to  divide  into  two,  a  third  perhaps  abeady  into 
foui%  and  a  fourth  has  abeady  resolved  itself  into  its  eight  secondary  cells. 
Very  often  most  of  the  primordial  cells  are  found  already  completely  sepa- 
rated into  eight,  while  one  or  other  of  them  is  still  whoUy  unaltered. 

'*'  When  the  act  of  division  has  gone  on  favoui-ably  up  to  the  point  to  which 
we  have  followed  it  above,  some  houi's  elapse  before  the  young  families  of  cells 
escape  completely  from  the  envelope.  The  process  which  precedes  their  birth 
consists  principally  in  the  more  complete  isolation,  in  a  centiifugal  direction 
around  their  common  centre,  of  the  secondary  cells  produced  by  each  pri- 
mordial cell.  Since  the  parting  off"  of  the  secondary  ceUs  advances  gradually 
from  the  periphery  towards  the  centre,  they  are  ah-eady  completely  indivi- 
dualized and  separated  by  intercellular  spaces  at  the  periphery,  while  aU  eight 
remain  still  connected  in  the  centre  into  a  common  colourless  mucous  mass 
filled  with  protoplasm-granules  (XIX.  42).  But  the  flow  of  the  contents  fi'om 
the  centre  to  the  borders,  which  continues  up  to  this  time,  at  length  causes 
the  constriction  of  the  central  mass  of  protoplasm  also  into  eight  parts ;  the 
eight  secondary  cells  then  appear  of  a  deep  yellowish  green  externally,  passing 
internally  into  colourless  green  towards  finely  granular  beaks  which  are  all 
connected  in  the  centre,  but  become  gradually  attenuated,  torn  away,  and 
retracted.  Then  the  young  primordial  cells  become  rounded  into  short 
eyhnders  and  stand  in  a  circle,  mthout  organic  connexion,  but  placed  closely 
beside  one  another :  seen  from  above  (in  the  polar  view),  under  the  micro- 
scope, they  resemble  a  wheel  mth  eight  notches  ;  from  the  side,  examined  in 
the  equatorial  view,  we  see  four  or  eight  short  cylinders  lying  side  by  side, — 
so  that  the  whole  is  not  unhke  a  small  Sceneclesmus  ohtusus  (XIX.  57—58). 

"  The  primordial  cell  undergoing  division  behaves  as  a  ivhole  towards 
external  things,  until  the  parting  ofi"  into  eight  is  quite  completed  ;  that  is  to 
say,  its  two  cilia  move  uninterruptedly,  and  consequently  the  entii'e  Ste- 
phanosj>ha^ra-g\obo  still  rolls  through  the  water  according  to  the  known  laws, 
even  when  most  of  its  primordial  cells  have  abeady  become  more  or  less  com- 
pletely divided  into  four  or  eight  secondary  cells.  Only  shortly  before  the 
completion  of  the  division  do  the  cilia  of  the  parent- cell  lose  their  motion  and 
disappear,  it  may  be  by  being  retracted  or  by  being  thrown  off";  but  the 


OF  THE  PHYTOZOA.  173 

orifices  through  which  the  cilia  previously  passed  out  into  the  water  may 
now  be  observed  in  the  common  envelope-cell,  as  minute  points  surrounded 
by  a  thickened  border. 

"  Immediately,  after  that,  it  is  seen  that  the  newly-formed  secondary  cells 
have  developed  their  ovvn  cilia;  for  the  yoimg  generations  formed  in  the 
interior  of  the  parent- envelope  now  begin  to  move  and  to  roll  over  like  a 
wheel,  so  far  as  the  confined  space  allows  of  this.  In  consequence  of  this 
movement  of  the  eight  small  wheels  rotating  in  the  interior  of  the  common 
envelope- cell,  which  constitutes  a  very  pretty  object,  the  parent-cell  soon 
becomes  enlarged  and  attenuated  at  certain  points ;  the  cellulose  of  which  it 
is  composed  appears  to  be  transformed  into  soluble  jeUy,  and  soon  afterwards 
one  after  the  other  breaks  through  out  of  the  common  envelope  and  revolves 
fi'eely  and  independently  in  the  water,  according  to  the  same  laws  as  the  old 
spheres,  but  more  actively  and  energetically.  The  young  Sfej)hanoSjphcera 
exactly  resembles  a  green  wi-eath  composed  of  eight  small  cylinders,  upon 
which  by  itself  no  envelope  and  cilia  can  be  detected  (XIX.  42,  48,  49) ;  but 
if  killed  with  iodine,  the  eight  primordial  cells  are  seen  to  be  siuTounded  by  a 
common  envelope-cell  in  the  form  of  an  exceedingly  delicate  membrane, — only 
this  lies  in  all  parts  almost  immediately  upon  the  green  globes,  so  that  it 
follows  the  waved  outline  they  produce,  and  in  its  total  form  resembles  a  flat 
spheroid  mth  eight  notches  on  its  border ;  it  is  perforated  by  the  cHia,  which 
go  off  in  pairs  from  each  of  the  primordial  cells  ;  and  two  chlorophyll-utricles 
are  already  distinguishable  in  the  latter.  By  degrees  the  envelope-cell  is 
hfted  up  by  the  endosmotic  absorption  of  water ;  its  surface  becomes  smoothed 
out,  and  it  appears  cii'cular  in  the  polar  view ;  on  the  other  hand,  it  retains 
for  a  longer  time  the  form  of  an  almost  tabular  spheroid,  and  hence  presents  an 
ellipse  in  the  equatorial  view  (XIX.  58) ;  finally  it  expands  uniformly  in  aU 
directions  and  thus  acquii-es  its  normal  spherical  form,  while  at  the  same 
time  it  becomes  considerably  thickened.  This  whole  process  of  propagation 
is  completed  duilng  the  night ;  and  on  bright  days  Stephanosphcercn  are  rarely 
seen  in  coiu^se  of  division  at  sunrise ;  on  dull  days  they  may  be  observed  in 
this  condition  in  the  first  part  of  the  morning. 

"  The  primordial  cells,  however,  not  unfrequently  come  to  a  standstill  in 
the  stage  of  division  of  the  second  generation,  so  that  they  only  separate  into 
four  secondary  cells ;  these  at  once  develope  clLia  and  an  envelope-cell,  with- 
out dividing  a  third  time,  and  make  their  exit  from  the  parent-envelope  in 
this  condition.  Here  therefore  only  the  first  generation  of  each  primordial 
cell  is  a  transitional  generation,  the  second  already  a  permanent  generation. 
Hence  arises  the  circumstance  that  we  often  find,  among  other  eightfold  Ste- 
phanosphcera-glohes,  some  in  which  the  envelope-cell  encloses  only  four  pri- 
mordial cells  standing  at  equal  distances,  which  in  other  respects  behave  in 
the  ordinary  manner. 

"It  is  still  more  frequently  observed,  when  the  primordial  cells  have 
already  become  constricted  into  four  secondary  cells  and  are  beginning  to 
divide  again  iuto  eight,  that  this  j)rocess  of  division  is  not  perfectly  completed 
in  aU  foui'  portions,  but  that  the  young  Stephanosphcera  abeady  becomes  free 
and  developes  the  envelope-cell,  although  one  or  other  of  the  four  quadratic 
segments  of  the  sphere  has  become  constricted  but  not  parted  off.  Hence  origi- 
nate monstrous  forms,  since  the  general  envelope-cell  then  encloses  only 
seven  primordial  cells  ;  but  in  these  cases  it  is  always  observed  that  one  of 
them  is  distinguished  by  most  curious  prolongations  or  mucous  filaments,  that 
it  appears  twice  as  large  as  the  rest,  that  it  contains  four  chlorophyll-utricles 
instead  of  two  as  is  usual,  and  that  it  is  also  more  or  less  constricted  in  the 
middle.     AU  this  furnishes  proof  that  here  one  secondary  cell  of  the  second 


174  GENERAL  HISTOEY  OF  TKE  I]!^FUSORIA. 

generation  has  not  been  divided  the  third  time  like  the  rest,  but  occupies  by 
itself  the  space  which  is  ordinarily  filled  by  two.  Very  often  only  six,  or 
even  no  more  than  five  primordial  cells  are  found  in  one  envelope-cell ;  but 
then  two  or  three  of  these  are  twice  as  large  as  elsewhere.  In  like  manner 
Alex.  Braun  figures  a  Pediastrum  composed  of  fifteen  instead  of  sixteen  cells, 
wherein  one,  hoAvever,  is  twice  as  large  as  the  rest. 

"-  On  the  whole,  it  is  ob\ious  that  the  mode  of  propagation  o{  StejyJianosjyhcera 
already  examined  corresponds  completely  to  that  we  are  akeady  acquainted 
with  as  formation  of  macroc/onidia  in  Chlamydococcus.  It  both  cases  it  de- 
pends upon  the  envelope-cell  remaining  unaltered,  while  the  primordial  cells 
become  divided,  first  into  two  secondary  cells,  and  then  so  on  in  a  lower 
power  of  two,  each  of  the  secondary  cells  immediately  developing  two  cilia,  and 
secreting  over  its  whole  surface,  as  do  all  primordial  utricles  of  vegetable 
cells,  a  delicate  cellulose  membrane,  which,  however,  becomes  gradually  re- 
moved further  from  the  secreting  primordial  cell  through  absorption  of  water. 
The  only  distinction  between  Chlamydococcus  and  Steplianosphcera  arises  from 
the  formation  of  a  special  envelope-cell  to  each  individual  secondary  cell  in 
Chlamydococcus,  while  in  Stephanos2yhcera  all  the  generations  produced  by 
division  form  one  primordial  cell,  become  enclosed  by  a  common  envelope, 
and  move  away  as  famUies  of  cells.  On  the  contrary,  the  developmental 
history  of  Gonium,  Pandorina,  and  Volvox  agrees  in  all  essential  particulars 
with  the  laws  of  propagation  which  I  have  just  described  in  Steiyhanosphcera, 
as  will  be  shown  elsewhere.  We  may  call  the  mode  of  multiplication  of  the 
Volvocinece  by  the  general  name  oi propagation  hy  macrogonidia. 

"  Another  process  is  met  with  in  Stephanosphcera,  besides  the  above,  and 
which  I  have  observed  more  rarely,  viz.  propagation  hy  microgonidia.  In 
this  mode  of  multiplication  the  introductory  processes  are  exactly  like  those 
of  the  formation  of  macrogonidia ;  in  particular  each  primordial  cell  is  at  first 
divided  into  two,  then  into  foui%  and  lastly  into  eight  secondary  cells.  But 
instead  of  this  third  generation  being  permanent  and  becoming  free,  as  is 
usual,  it  not  unfrequently  happens  that  the  process  of  division  is  not  arrested 
with  the  separation  into  eight — that  the  original  primordial  cell  becomes 
parted  off  a  fourth,  fifth,  and  even  a  sixth  time,  in  the  same  manner,  and  at 
length  is  broken  up  into  a  large  number  of  cells  (16,  32,  64),  which  naturally 
are  so  much  the  smaller  the  greater  nimiber  of  times  the  subdivision  into  two 
has  taken  place  (XIX.  43,  51).  These  little  secondary  cells  finally  become 
totally  separated  from  one  another,  Tvithout  secreting  an  envelope-cell.  These 
little  cellules — 1  shall  follow  the  example  of  Alex.  Braun  and  call  them 
microgonidia — exhibit  a  very  active  and  energetic  motion  inside  the  envelojDe- 
ceU,  huiTj-ing  very  rapidly  up  and  down  in  all  directions  in  its  cavity,  pro- 
ducing by  their  great  number  that  ciu'ious  swarming  which  Alex.  Braun  has 
very  aptly  compared  with  the  interminghng  of  a  crowd  of  people  in  a  confined 
area,  where  every  one  is  constantly  changing  his  place,  while  the  whole 
together  constantly  occupy  the  same  space.  Sometimes  the  cellules  are 
scattered  in  a  few  large  masses ;  then  they  unite  again  into  a  knot  in  the 
middle ;  every  moment  the  general  aspect  varies.  At  length  the  common 
envelope  is  ruptured  where  the  microgonidia  emerge  one  after  another  or  in 
large  masses,  but  free  and  singly,  into  the  water.  Their  true  form  may  be 
then  readily  detected  by  killing  them  with  iodine ;  they  are  spindle-shaped 
and  acuminated  at  both  ends,  bright  green  in  the  middle,  and  run  out  into  a 
colourless  beak  at  each  end,  on  the  whole  not  imlike  young  Eugleyice,  without 
a  trace  of  an  envelope-cell ;  the  extremity  which  goes  first  in  their  swimming 
bears  delicate  ciha  ;  the  number  of  the  cilia  is  four  (XIX.  52).  "WTien  the 
microgonidia  reach  the  water  they  move  most  actively  in  all  directions,  and 


OF  THE  PHYTOZOA.  175 

in  a  short  time  all  the  corpuscles  emitted  from  an  envelope-cell  are  scattered 
and  disappear  in  the  wide  surface  of  the  drop  of  water. 

''I  have  not  been  able  to  make  out  what  becomes  of  the  microgonidia 
subsequently,  since  they  are  ordinarily  decomposed  on  the  object-holder  after 
a  brief  swarming ;  but  it  may  be  conjectiu^ed  that  they  also  serve  for  propa- 
gation, and  probably  pass  into  a  condition  of  rest.  At  least  the  latter  has 
been  observed  in  the  microgonidia  of  Chlamydococcus  pluvialis  by  Alex.  Braun 
and  myself:  the  history  of  the  development  of  the  latter  agrees  wholly  with 
those  of  the  Stephano  splicer  a  ;  they  originate  also  by  the  di\'ision  of  the  pri- 
mordial cell  in  a  higher  power,  are  distinguished  by  their  minute  size  and 
more  active,  peculiarly  Infusorioid  movement,  and  never  develope  an  envelope- 
ceU  duiing  their  movement.  The  microgonidia  of  both  therefore  are  true 
primordial  cells ;  that  is,  primordial  utricles  resembling  cells,  organized  ex- 
clusively of  coloured  protoplasm,  without  any  cellular  membrane.  The  only 
distinction  between  them  is,  that  the  microgonidia  of  Chlamydococcus,  like 
their  macrogonidia,  possess  two  cHia,  while  in  those  of  StephanospJicera  I 
observed  four.  That  the  microgonidia  of  Stephanosphcera  correspond  per- 
fectly in  moi'phological  respects  to  the  macrogonidia,  and  only  depend  upon  a 
higher  power  of  division,  is  proved  by  a  case  in  which  seven  out  of  the  eight 
primordial  cells  in  one  envelope-cell  were  broken  up  into  microgonidia,  while 
one  divided  merely  into  eiglit  secondary  cells ;  the  latter  were  developed  as 
macrogonidia,  and  formed  a  connected  wreath  suiTounded  by  an  envelope-cell, 
which  rolled  slowly  about  in  the  parent- envelope,  suzTOunded  by  the  swarm 
of  fi'ee,  rapidly  moving  microgonidia. 

"  Abstracting  the  differences  which  may  be  shown  always  between  two 
genera,  we  detect  the  same  law  of  development  in  Hydrodictyon  as  m  Stepha- 
nosphcera, — viz.  the  bicHiated  less  numerous  macrogonidia  arrange  them- 
selves into  a  family  of  cells  abeady  "within  the  parent-cell,  according  to  the 
character  of  the  given  conditions  of  the  two  genera,  the  cell-family  being 
active  in  the  Volvocineoe  and  immoveable  in  the  Protococcacece,  while  the 
more  numerous  more  actively  moving  microgonidia  with  foui'  cHia  leave  the 
parent-cell  and  enter  upon  a  metamorphosis,  the  retrogradation  from  which 
to  the  normal  type  of  the  genus  has  not  been  observed  yet  here,  or  indeed  in 
the  microgonidia  of  any  of  the  Algae.  Such  an  mideniable  agreement  of  the 
law  of  development  of  Stephanosphct^ra  with  an  undoubted  plant  like  Hydro- 
dictyon, which  testifies  to  a  near  relationship,  would  be  inconceivable  if  the 
former  were  to  be  regarded  as  of  essentially  different  organization — as  belong- 
ing to  quite  another  kingdom  of  nature.  Thus  the  developmental  history  of 
Stephanosphcera  also  fiu'nishcs  the  most  convincing  proof  of  the  vegetable 
nature  of  this  genus,  and  consequently  of  the  Volvocineoe  generally. 

"  That  the  formation  of  macro-  and  microgonidia  does  not  exhaust  the 
whole  series  of  forms  which  Steplianosphcera  may  pass  through,  is  proved  by 
the  following  observation,  which  unfortunately  I  have  not  yet  been  able  to 
complete.  Having  cultivated  some  Stephanospliaerce  for  a  long  time  in  a  little 
glass  cup,  in  the  way  described  in  my  essay  on  Loxodes  bursaria  (7.  c),  all 
the  primordial  cells  at  length  exhibited  dark,  thick,  greenish  brown  contents, 
so  densely  filled  with  numerous  granules  that  the  two  chlorophyll-vesicles 
could  no  longer  be  detected ;  their  form  was  more  or  less  globular,  and  the 
mucous  radiating  processes  were  entirely  absent ;  their  outlines  were  remark- 
ably sharply  defined,  as  if  they  had  become  suiTounded  by  a  rigid  membrane. 
At  the  same  time  I  remarked  that  the  primordial  cells  were  no  longer  fixed 
immoveably  at  the  periphery  of  the  envelope  cell,  never  changing  their  relative 
positions,  but  jerked  backwards  and  forwards,  finally  tore  themselves  away 
from  the  envelope -cell,  and  then  began  to  rotate  slowly  and  lazily  in  the  interior. 


176  GENERAL  HISTORY  OP  THE  INFIISOEIA. 

Soon  after,  I  saw  the  envelope-cell  also  burst  at  some  spot  and  collapse  ;  and 
the  eight  primordial  cells  gradually  emerged,  one  after  another,  as  inde- 
pendent globes :  they  were  now  seen  to  be  enclosed  in  a  pretty  closely  applied 
envelope,  through  which  penetrated  two  cilia ;  and  hence  they  presented  the 
utmost  resemblance  to  Chlcnnydomonas  Pidviscidus.  They  moved  about  for 
some  time  in  the  water  and  at  length  came  to  rest,  losing  their  cilia  and  accu- 
midating  like  Utile  green  Protococcus-glohides  at  the  bottom  of  the  glass.  We 
therefore  have  here  a  motionless,  perfectly  plant-like  stage  of  Stephanosphcera , 
such  as  we  are  acquainted  -^ith  in  Chlamydococcus  and  Chlamydomonas ;  the 
remainder  of  the  Volvocinece  undoubtedly  pass  into  a  similar  condition  of 
rest,  which  is  the  means  of  their  preservation  when  the  Avater  of  ditches  is 
diied  up  in  summer.  The  emergence  of  single  globes  from  the  common  enve- 
lope, in  a  form  resembling  Chlamydomonas,  may  also  be  readily  observed  in 
Goniimi. 

''  I  conjecture  that  the  motionless  Protococcoid  ceUs  of  Stephanospho'.ra  are 
the  means  of  the  presei^ation  of  the  species  when  the  water,  as  is  always 
the  case  in  the  shallow  hollows  in  stones,  their  natural  station,  is  diied  up 
for  a  long  time  and  all  the  living  inhabitants  are  precipitated  on  the  stone. 
The  observations  of  Major  von  Flotow  have  already  demonstrated  that  the 
dried-up  muddy  sediment  always  reproduces  StephanosphcBrcE  when  water  is 
again  poured  on  to  it.  This  capahility  of  reviving  from  the  dried  condition 
is  shared  hj  Stephanospha^ra  Avith  Chlamydococcus  pliivialis,Yn.  which  likewise 
the  motionless  cells  remain  living  after  being  diied  up  for  years,  and  are  capa- 
ble of  giving  birth  to  moving  forms,  while  the  swarming- cells  themselves  are 
destroyed  for  ever  by  rapid  desiccation.  Herr  von  Flotow  has  sent  earth  with 
dried  htephanospha'rce  to  Dr.  Rabenhorst  in  Dresden,  who,  in  like  manner, 
succeeded  in  reviving  them  by  moistening. 

"  Since  the  moving  Stephanosj^hcera?  are  destroyed,  just  like  the  swarming- 
cells  of  Chlamydococcus,  by  rapid  desiccation,  I  believe  that  the  motionless 
Protococcoid  globes,  the  development  of  which  I  have  just  described,  are  the 
fonns  which  do  not  lose  their  vitality  by  diying,  but  are  capable,  when  wetted 
again  with  water,  of  going  through  a  cycle  of  development,  by  which  they 
return  to  the  normal  mo\T.ng  form  of  Step>hanosphcera,  Yet  I  must  remark 
that  I  have  not  hitherto  obtained  sufficient  material  to  observe  the  resting 
Stephanosphcera,  and  to  trace  the  processes  which  occm^  in  the  revivification. 

*'  Respecting  their  vital  manifestations,  repeated  experiments  showed  that 
the  moving  spheres  of  Stephanosphaera  seeh  the  darlcer  part  of  the  vessel,  avoid- 
ing however  a  total  absence  of  light,  and  assembling  in  preference  in  a  moderated 
light  or  half-shadoiv.  Since  other  Algse  and  Infusoria  exhibit  a  different 
beha\doui'  towards  the  light,  we  thus  possess  a  means  of  sorting,  to  a  cer- 
tain extent,  the  microscopic  inhabitants  of  a  specimen  of  water,  as  I  did  the 
shade-loving  Stephanosphcerce  from  Chlamydococcus,  which  ordinarily  seek  the 
brightest  light." 

An  important  appendix  to  this  histoiy  of  Stephanosphcera  has  quite  recently 
appeared  from  the  joint  labours  of  Professor  Cohn  and  Wichura  {Nov.  Act. 
Acad.  Curios.  Natures,  1857,  Part  I.),  and  has  been  translated  into  English 
by  Mr.  Currey  {J.M.S.  1858,  p.  131). 

The  resting- stage  above  spoken  of  is  again  referred  to  concisely  and  clearly 
in  this  paragraph : — "  Under  ceriain  circumstances  each  of  the  eight  cells 
secretes  a  cellular  covering,  and  swims  about  in  the  interior  of  the  globe  in 
the  form  of  free  Chi amijdomonas -like  cells  (XIX.  44)  ;  eventually  they  escape, 
either  by  fissm'e  of  the  globe,  or  by  its  gradual  dissolution,  lose  their  cilia, 
form  a  thicker  membrane,  become  motionless,  and  accumulate  at  the  bottom 
of  the  vessel.    If  the  vessel  be  then  permitted  to  become  thoroughly  diy,  and 


OF  THE  PHYTOZOA. 


afterwards  be  again  filled  with  water,  motile  Stej>hanos^hcerce  reappear,  from 
which  it  seems  probable  that  the  green  globes  are  the  resting-spores  of  the 
plant."  These,  it  may  be  added,  are  with  difficulty,  if  at  all,  distinguishable 
from  those  of  Chlamydococcus  pluviaVis :  they  vary  very  much  in  size,  and 
apparently  grow  after  entering  on  the  state  of  rest.  Their  coloiu'  is  deep 
green  (occasionally  yellowish  or  ohve) ;  and  they  have  a  nucleus,  and  fre- 
quently a  nucleolus.  We  cannot  do  better  than  copy  Mr.  Currey's  abridged 
translation,  in  endeavouiing  to  convey  the  results  arrived  at  by  Cohn  and 
Wichura : — 

''  When  the  water  is  permitted  to  evaporate  graxlually,  the  resting- cells 
become  yellow,  and  afterwards  orange  or  red,  and  their  contents  have  a  more 
oily  appearance.  The  authors  found  that  if  the  water  was  not  permitted  to 
evaporate,  the  resting-spores,  although  continuing  to  live,  did  not  become 
developed  into  Steijlianosphcerce  ;  but  when  fresh  water  was  poiu-ed  upon  de- 
siccated resting-spores,  twenty-four  hours  sufficed  for  the  production  of  motile 
Steplia  nosjyhcf^i'ce. 

''The  following  is  the  process  of  transformation  from  the  state  of  rest  into 
'the  motile  form. 

"  The  dried  resting-spores  take  up  the  water,  and  their  contents  (hitherto 
somewhat  misshapen)  gradually  fill  up  the  cavity  of  the  containing  mem- 
brane, and  become  cloudy  and  granular ;  the  border  becomes  yellowish,  and 
the  red  coloimng  matter  is  concentrated  in  the  centre.  The  cells  then  begin 
to  divide ;  and  the  successive  forms  assumed  in  this  process  will  be  better 
imderstood  by  reference  to  XIX.  44-47,  than  by  description.  In  pass- 
ing from  the  state  shown  in  fig.  45  to  that  shown  in  fig.  46,  the  outer  mem- 
brane has  gradually  become  invisible.  Up  to  fig.  47  the  process  has  occupied 
about  two  hoiu-s.  The  four  daughter-ceUs  (fig.  47)  begin  to  quiver,  and  to 
endeavour  to  separate  from  one  another.  Two  cilia  are  now  perceptible  at 
the  pointed  extremity  of  each  of  the  four  ceUs,  by  the  action  of  which  the 
group  begins  to  move  as  a  whole,  and  in  a  laboui'ed  manner,  in  the  water ; 
ultimately,  however,  all  trace  of  the  enveloping  membrane  and  of  the  gluti- 
nous connecting  substance  disappears,  and  one  by  one  the  daughter- ceUs 
escape  and  become  free.  Pigs.  48  and  49  exhibit  different  forms  of  these 
free  daughter-cells,  which  contain  two,  three,  or  several  granules  (amylon  ?) 
and  sometimes  also  vacuoles.  The  sharp  end  is  often  prolonged  into  a  coloui^- 
less  beak.  At  this  period  there  is  no  proper  cellulose  membrane.  At  the 
moment  of  escaping,  their  diameter  never  exceeds  O'OIO  mm. ;  but  they  soon 
enlarge  and  attain  a  diameter  of  0-013  to  0-015  mm. 

"  Their  form  and  the  length  of  the  beak  are  variable,  the  latter  being  some- 
times altogether  wanting.  In  form  and  motion  they  resemble  exactly  the  naked 
primordial-cells,  which  are  produced  by  division  from  the  resting-cells  of 
Chlamydococcus  lyiuvicdis.  The  authors  have  never  seen  the  resting-cells  of 
SteplianospJiceroi  di\ide  into  more  than  four  parts,  but  think  it  not  improbable 
that  division  into  a  greater  number  (eight  or  possibly  sixteen)  sometimes 

OCCUl'S. 

''  The  length  of  time  which  elapsed  between  the  immersion  of  the  diied 
resting-spores  and  the  fii^st  appearance  of  the  motile  ceUs  varied  from  nine  to 
twenty-four  houi^s.  It  was  noticed  that  those  resting-spores  which  did  not 
produce  zoospores  within  six  days  never  did  so  afterwards,  although  they 
continued  to  live  and  were  perfectly  healthy. 

''  Zoospores,  produced  in  the  month  of  November,  did  not  advance  beyond 
the  fii'st  stage  (fig.  49).  Others,  however,  produced  in  March,  remained  only 
a  few  houi\s  in  that  condition,  after  which  time  a  delicate  membrane  was 
formed  round  the  body  of  the  piimordial  cell  (XIX.  50  );  this  membrane  was 


178  GENERAL  HISTORY  OF  THE  INFUSORIA. 

at  first  closely  attached  to  the  primordial-cell,  but  became  gradually  enlarged 
by  absorption  of  water  into  a  colouiiess  enveloping  vesicle  (figs.  50,  54), 
usually  globular  but  sometimes  oval,  having  two  openings,  thi'ough  which  the 
ciha  penetrate.  In  this  condition  they  attain  a  diameter  of  0-017-0-022'", 
and  are  not  distinguishable  from  encysted  forms  of  Chlamydococcus  plu- 
vialis.  Other  zoospores,  produced  on  the  1st  of  April,  1857,  attained  a  larger 
size ;  and  the  protoplasm  of  the  primordial  cell,  instead  of  retaining  its  con- 
tinuous outline,  became  elongated  here  and  there  into  simple  or  forked  muci- 
laginous rays,  which  were  either  colourless  or  green  from  the  presence  of 
chlorophyll  (fig.  53).  These  rays  are  probably  produced  by  the  protoplasm 
adhering  at  certain  points  to  the  surrounding  membrane,  and  being  carried 
outwards  by  its  growth. 

The  Chlamydococcus-]ike  form  only  lasted  a  few  hours :  towards  the  even- 
ing the  zoospores  mostly  began  to  divide.  In  the  first  place,  the  protoplasmic 
rays  are  di^awn  in,  and  the  primordial  cell  becomes  roimd ;  it  then  elongates 
itself  in  the  direction  of  an  axis  passing  through  the  point  of  origin  of  the 
ciha,  and  by  the  process  of  division  assumes  the  forms  shown  in  figs.  54  and 
55.  This  state  is  usually  attained  by  about  nine  o'clock  in  the  evening ;  and 
about  eleven  o'clock  a  constriction  commences  in  a  plane  at  right  angles  to 
the  former  plane  of  division ;  and  eventually  the  primordial  cell  is  divided  into 
quadi\ints,  each  containing  a  nucleus  and  a  portion  of  the  red  substance.  The 
two  cilia,  which  have  retained  their  activity,  originate  in  the  interspace  be- 
tween two  quadi^ants.  About  midnight  usually,  but  sometimes  earlier,  con- 
striction recommences,  and  the  form  in  fig.  56  is  attained.  This  constriction 
proceeds  towards  the  middle  point  of  the  spheroid,  by  which  the  quadrants  are 
bisected,  and  ultimately  divided  into  eight  wedge-shaped  portions,  whose  con- 
tour-hnes,  like  the  spokes  of  a  wheel,  meet  in  the  middle. 

"  And  now  commences  a  further  process  of  development,  which  forms  the 
ground  of  the  generic  distinction  between  Stephanosplicera  and  Chlamydo- 
coccus. For,  whilst  in  Chlamydococcus  the  indi\4dual  portions  of  a  piimor- 
dial  cell  separate  entirely  from  one  another,  each  developing  its  own  enveloping 
membrane,  and  ultimately  escaping  as  a  unicellular  individual,  in  Stephano- 
sphceyxt,  on  the  other  hand,  the  eight  portions  remain  united  as  a  family.  The 
coloured  contents  of  the  individual  portions  become  drawn  back  towards  the 
periphery  in  a  centrifugal  direction,  a  colourless  plasma  remaining  about  the 
central  point  ;  this  disappears  at  first  in  the  centre  ;  a  cavity  is  formed  in  the 
middle  of  the  disk  ;  and  as  this  enlarges,  the  eight  portions  assume  the  foim  of 
a  wreath,  consisting  of  eight  globular  or  ellipsoidal  bodies  in  close  contact 
(fig.  57),  and  usually  not  exactly  in  one  plane,  owing  to  the  outer  membrane 
not  having  expanded  in  proportion  to  the  enlargement  of  the  plasma.  The 
original  cilia  continue  active,  causing  the  motion  of  the  whole  organism,  until 
the  eight  portions  are  completely  individualized ;  and  then  their  motion  ceases : 
but  at  this  period  each  of  the  eight  parts  may  be  seen  to  be  provided  with  two 
ciha,  which  are  in  motion  so  far  as  their  limited  space  allows. 

The  separate  parts  of  the  plasma  now  form  eight  independent  but  closely- 
packed  membraneless  primordial  ceUs.  Shortly  afterwards  it  is  seen  that  a 
delicate  membrane,  common  to  them  all,  has  been  secreted  beneath  the  mo- 
ther-cell membrane,  round  the  disk  formed  by  the  primordial  cells ;  this 
membrane  at  first  lies  in  close  contact  with  the  latter  cells,  foUovving  the 
constrictions  of  the  disk,  but  afterwards  becomes  further  and  further  re- 
moved as  it  swells  and  tends  to  assume  a  globidar  form  (fig.  58),  By  the 
motion  of  the  cilia  the  mother- cell  membrane  is  gradually  thrown  ofif,  and  the 
young  family  escapes  into  the  water.  Its  eight  green  primordial  cells  still 
enclose  the  last  traces  of  the  red  substance,  which  gradually  disappears,  and 


OF  THE  PHYTOZOA.  179 

instead  of  which  are  seen  two  granules;  the  primordial  ceUs  are  in  im- 
mediate contact  at  the  sides,  and  are  of  an  oval  or  globular  shape ;  their 
common  enyeloping  membrane  is  at  first  constricted  at  the  border  following 
the  outHne  of  the  primordial  cells  ;  it  eventually  becomes  globular,  although 
continiung  for  a  long  time  much  flattened  at  the  poles,  in  the  form  of  a  disk- 
shaped  spheroid.  When  the  Chlamydococcus-like  unicellular  Sfej^hanosjyJicera 
has  commenced  its  division  early  in  the  evening,  the  di\'ision  into  eight  is 
perfected  during  the  night,  and  early  in  the  morning  the  young  family  quits 
its  cast-off  mother-cell  membrane. 

"  In  the  course  of  the  day  the  individual  primordial  cells,  and  their  common 
enveloping  membrane,  grow  until  the  latter  attains  a  diameter  of  0-040- 
0-048'".  Dming  this  growth  the  shape  of  the  primordial  cells  is  changed 
by  the  formation  of  various  prolongations  in  the  manner  above  described : 
but  in  the  coiu'se  of  the  afternoon  the  primorchal  cells  again  become  round ; 
and  during  the  evening,  division  commences  in  them  precisely  similar  to  the 
process  in  the  imicellular  Stephanosphceixi :  on  the  follo^dng  morning  we 
find  eight  young  families,  with  the  common  enveloping  membrane,  which 
soon  escape  and  go  through  the  same  process.  It  is  calculated  that  in  eight 
days,  imder  favoiu^able  circumstances,  16,777,216  families  may  be  formed 
from  one  resting-ceU  of  StepTianospli(xra.  It  is  remarkable  that  the  division 
of  the  primordial  ceUs  in  Steplianospluera  is  confined  to  a  certain  time  of  day : 
it  begins  towards  evening,  and  is  completed  the  following  morning.  In  the 
observations  made  in  Laj)land,  at  a  time  when  the  daylight  there  lasted  diuing 
the  whole  night,  the  beginning  and  end  of  the  division  were  observed  to  take 
place  at  almost  the  same  hours  as  in  the  observations  made  at  Breslau  m  the 
spring,  when  the  day  and  night  were  almost  of  equal  length.  Sometimes 
the  division  ceases  after  the  formation  of  only  four  primordial  cells.  On  one 
occasion  the  authors  observed  a  family  with  only  three  cells,  one  only  of 
the  two  halves  first  formed  having  undergone  a  second  division.  In  Lap- 
land a  family  with  sixteen  cells  was  once  observed. 

''  The  authors  then  proceed  to  discuss  the  natiu-e  of  the  resting-cells  in 
Stephanosjjhcera  and  CliJamydococcus,  and  come  to  the  conclusion  that  they 
are  not  spores ;  i.  e.  that  they  are  not  of  the  same  nature  as  the  red  cells  of 
(Edogonium,  BulhocJicete,  Draparnaldia,  CJicetopJiora ,  Sphceroplea ,  Volvocc,  &c. 

"  They  come  to  this  conclusion  upon  two  grounds :  1st,  that  the  resting- 
ceUs  in  question  continue  to  grow  after  becoming  quiescent ;  and  secondly, 
that  it  is  probable  (although  not  yet  proved)  that  the  resting-ceUs  increase 
by  self-division,  thus  producing  new  generations  of  resting- cells.  These  two 
characteristics  the  authors  consider  inconsistent  with  the  idea  of  a  spore. 

''  In  conclusion,  the  authors  notice  the  formation  of  microgonidia  in  Steplia- 
nosplicera,  which  takes  place  by  the  division  of  the  primordial  cells  into  num- 
berless small  portions.  Fig.  5  shows  a  Stephanosphcera,  in  which  seven  of  the 
eight  primordial  cells  have  formed  microgonidia  ;  the  individual  microgonidia 
(fig.  52  a,  h,  c)  become  free  by  the  disintegration  of  these  eight  groups  into 
their  constituent  portions.  The  authors  think  it  not  improbable  that  the 
microgonidia  exercise  an  impregnative  influence  in  spore -formation,  but  admit 
that  there  is  no  evidence  to  prove  it." 

Mr.  Currey  (J.  M.  S.  1858,  p.  209)  reopens  the  question  concerning  the 
natui^e  of  the  red  resting-cells  of  StephanospJicera,  and  argues  against  the 
conclusion  drawn  by  Cohn  and  Wichura.  He  says  those  observers  have 
noticed  ''  that  these  cells  in  Step}ianosp}i<r.ra  pluvialis,  which  are  at  first  of  a 
green  colour,  and  furnished  with  cilia,  increase  in  growth  after  the  green 
colour  and  the  cilia  have  disappeared,  i.  e.  after  they  have  assumed  a  state  of 
rest,  a  fact  which  they  consider  to  militate  against  their  character  as  spores. 

x2 


180  GENERAL  HISTORY  OF  THE  INFUSORIA. 

"  ^We  have  seen,'  they  say,  '  that  these  resting- cells,  after  they  have  been 
formed  by  the  metamorphosis  of  a  motile  primordial  cell,  increase  in  gTO"\vth 
considerably,  that  they  go  through  a  further  vegetatiye  development,  and 
have,  therefore,  not  reached  the  termination  of  their  vital  process.'  And 
they  then  add — '  It  is  contrary  to  the  idea  of  a  sj^ore,  that  it  should  continue 
to  grow  after  having  assumed  the  character  of  a  resting-cell ;  and  the  fact  has 
never  yet  been  observed  in  any  single  case.'  It  would  seem  that  these 
remarks  are  intended  to  be  limited  to  the  Algae ;  but  it  is  worthy  of  obsei-va- 
tion,  that  the  spores  of  the  ascigerous  Fungi  frequently  increase  in  gro^i;h 
after  escaping  from  the  asci ;  and  if  this  circumstance  is  not  to  be  looked  upon 
as  affecting  their  character  as  spores,  it  is  difficult  to  see  why  a  different  rule 
should  be  applied  to  the  Algae. 

"  Cohn  and  Wichui'a  moreover  consider  that  the  increase  by  self- division 
is  irreconcileable  with  the  idea  of  a  spore.  In  speaking  of  the  red  cells  of  Chla- 
mydococcus  pluvialis,  they  express  a  doubt  whether  in  those  cells  increase  by 
self-division  takes  place,  but  assert  that,  if  such  should  prove  to  be  the  case, 
it  would  be  conclusive  against  their  being  spores,  considering  self-division  (if 
I  understand  them  right)  to  be  a  process  of  vegetative  development  distinct 
from  germination.  These  observations  are  worthy  of  the  careful  attention  of 
microscopists ;  and  without  ventming  an  opinion  as  to  their  correctness,  I 
would  only  remark,  that  if  the  resting-cells  of  Chlamydococcus  and  Stejpha- 
nosphcera  are  not  to  be  considered  spores,  that  character  must  also  be  denied 
to  the  resting-cells  of  (Edocjonium,  BidhocJicete,  Draparnaldia,  Spli(xroplea, 
and  Volvox,  if,  as  is  more  than  probable,  there  should  be  detected  in  these 
latter  cells,  1st,  an  increase  in  growth  after  becoming  quiescent ;  or,  2dly, 
increase  by  seK- division." 

YoLvox  (XX.  32-49). — This  genus  lias  always  been  an  especial  favour- 
ite -^ith  microscopical  students.  Its  colonies  of  numerous  monadiform  green 
bodies  distributed  over  the  surface  of  miniatui'e  globes,  endowed  with  active 
motion,  revolving  hither  and  thither,  form  one  of  the  most  pleasing  objects 
that  the  microscope  can  display.  Moreover,  the  more  minutely  the  globes  of 
the  Volvox  are  exammed,  the  more  interest  do  they  awaken,  by  reason  of  the 
regularity  and  beauty  of  their  intimate  structure,  and  of  the  results  of  their 
\-ital  processes. 

The  consequence  of  this  has  been  a  host  of  observers  and  writers  on  the 
anatomy  and  physiology  of  Volvox,  and  a  formidable  array  of  conflicting 
views  on  those  topics,  the  consequence  of  careless  and  insufficient  research, 
of  indifferent  instruments,  and  of  the  influence  of  fanciful  hypotheses.  We 
shall,  however,  attempt  no  analysLs  of  the  many  accoimts  of  Volvox  in 
existence,  but  restrict  ourselves  to  an  abstract  of  the  more  recent  important 
observations  and  conclusions  of  Professors  Williamson  and  Busk,  particularly 
of  the  former  and  earher  observer  on  that  org^anism,  premising  it  by  a  brief 
notice  of  Ehrenberg's  views. 

Formerly  the  whole  globular  mass  was  regarded  as  a  single  warty  and 
ciliated  animalcule  ;  and  the  act  of  bursting,  whereby  the  smaller  globes  de- 
veloped within  it  which  had  reached  maturity  were  liberated,  was  considered 
to  be  the  birth  of  young  animals.  This  theory  Ehrenberg  clearly  proved  to 
be  erroneous,  and  showed  that,  to  iLse  liis  language,  the  supposed  spherical 
animalcule  was  in  reality  a  colony  of  monad-like  beings  distributed  over  the 
inner  surface  of  a  common  lorica,  and  connected  together  by  fihform  cords  or 
tubes ;  in  other  words,  he  proved  each  sphere  or  globe  to  be,  if  we  may  so 
term  it,  a  hoUow  cluster  of  many  hundi^eds  or  even  thousands  of  h\-ing  occu- 
pants, and  to  frequently  contain  within  it  other  smaller  hoUow  spheres, 
similar  in  nature  to  itself,  and  in  fact  developed  from  it  by  a  process  of  self- 


OF  THE  PHYTOZOA.  181 

cli^•ision.  The  result  of  these  considerations  led  Ehrenherg  to  perceive  the 
true  homology  between  the  spheres  of  Volvocc  and  the  four-sided  tablets  of 
Gonium. 

Each  member  of  the  colony,  he  added,  has  an  individuality  of  its  own,  and 
to  all  appearance  resembles  an  ordinaiy  simple  monad,  enclosed  mtliin  a 
lorica  (a  Jaeerna),  having  a  red  eye-speck,  a  double  filiform  proboscis  or 
filament  protruding  from  the  suiface  of  the  common  spherical  lorica  and 
giving  the  hairy  or  ciliated  appearance  to  it,  and  at  the  base  of  these  filaments 
a  mouth,  indicated  by  a  bright,  clear  spot.  Internally  Ehrenherg  believed 
he  discerned  clear  digestive  cells,  a  contractile  seminal  vesicle,  one  or  two 
roimd  sexual  glands,  and  numerous  green  ova.  The  following  histoiy  of 
Volvox  conveys  the  present  state  of  information  and  opinion  on  this  interest- 
ing organism. 

The  globes  of  Volvox  are  bounded  externally  by  a  hyaline  structui-eless 
membrane  or  pellicle,  which  corresponds  to  the  "  envelope-cell"  as  understood 
by  Cohn  (XX.  34,  45).  Distributed  on  the  inner  wall  or  surface  of  this  mem- 
brane, is  (in  Cohn's  words  /.  M.  S.  1857,  p.  140)  "  an  infinitude  of  very 
minute  hexagonal  cells,  attached  to  each  other  in  the  same  way  as  are  the 
elements  of  an  epidermic  tissue"  (XX.  38).  The  protoplasmic  matter  or 
the  endochrome  of  each  cell  constitutes  the  presumed  monad  of  Ehi-enberg, 
which  is  flask-shaped,  and  protrudes  its  tapering  extremity  or  neck  outwards, 
bearing  at  its  apex  two  ciliaiy  filaments  which  penetrate  the  common  envelope 
and  vibrate  freely  in  the  surrounding  water. 

The  green  substance  composing  each  monadiform  individual  or  "^  primordial 
cell,"  is  the  usual  vegetable  protoplasm,  and  contains  chlorophyll- vesicles,  a 
clear  globule  or  nucleus,  one  or  rarely  two  contractile  vesicles,  and  usually  a 
brownish-red  speck,  regarded  by  Ehrenherg  as  a  ^dsual  organ  (XX.  35) ;  the 
filaments  are,  as  usual,  productions  from  the  protoplasm.  Further,  each  green 
globule  is  enveloped  in  one  or  more  partially  organized  special  membranes, 
which  are  in  more  or  less  close  apposition  with  it  according  to  the  age  and 
the  conditions  of  Kfe  under  which  the  Volvox  is  placed  (XX.  35, 37),  and  give 
it  the  essential  characters  of  a  cell  vrith  a  cell- wall.  In  the  early  stage  of 
development  the  several  protoplasmic  masses  in  a  colony  are  closely  aggre- 
gated ;  but  as  age  advances,  a  clear  interval  surrounds  and  separates  them, 
traversed  by  several  prolongations  of  the  protoplasmic  matter  connecting 
together  adjoining  cells  (XX.  37).  These  processes  extend  outwards  hke  so 
many  rays  from  each  primordial  cell,  and  as  a  rule  encounter  those  fi^om  sur- 
rounding cells  at  a  determinate  distance,  where  they  meet  with  an  external, 
deHcate,  transparent  membrane — the  wall  of  the  cell  of  which  the  central 
green  globule  represents  the  nucleus.  This  thin  membrane  forms  the  boimd- 
ary  of  each  clear  space  surrounding  the  contained  green  globule  ;  and  from 
the  mutual  pressure  of  the  assemblage  of  cells  composing  the  Volvox,  it 
acquires,  as  seen  from  above,  a  hexagonal  figiu'e  (XX.  38,  39-41,  45). 

We  have  observed  abeady  that,  as  age  advances,  the  space  or  areola  around 
each  primordial  ceU  increases ;  that  is,  the  external  cell- wall  becomes  further 
detached  from  the  contained  protoplasmic  mass,  and  hence  the  processes  con- 
necting the  two — at  first,  and  even  for  some  considerable  time  during  active 
nutrition,  thick,  clumsy,  and  irregular  (XX.  42,  43) — become  gradually 
stretched,  until  they  are  eventually  converted  into  attenuated  threads  or 
almost  imperceptible  lines.  In  fact,  by  over-distension  of  the  cells  from 
any  cause,  whether,  as  commonly  happens,  from  advancing  age,  or  from  the 
breaking  up  of  the  globe,  these  cords  get  mptui-ed,  and  then,  by  retracting 
themselves  from  the  outer  delicate  ceU-waU,  coalesce  with  the  protoplasmic 
central  mass.     On  comparing  this  structm-e  mth  that  of  Goniwn  as  recorded 


182  GENERAL  HISTOR,Y  OF  THE  INEUSOEIA. 

by  Cohu,  a  close  homology  is  perceptible.  In  this  plant  the  membrane  sui'- 
roimding  the  hexagonal  primordial  cells  gives  off  from  each  angle  a  tubular 
process,  which  comes  into  intimate  apposition  at  its  extremity  with  that  from 
an  adjoining  cell.  However,  between  these  processes  of  Gonium  and  those  of 
Volvox,  there  is  this  diiference,  that  in  the  former  it  is  only  the  primordial 
membrane  which  is  drawn  out  to  form  a  canal  or  tubule,  whilst  in  the  latter 
the  protoplasm  itself  is  at  first  extended  with  its  membrane,  and  subsequently 
collapses  into  a.delicate  band. 

The  circular  contractile  vesicle  noticed  by  Ehrenberg  has  had  its  existence 
confirmed  by  Mr.  Busk  in  mature  cells  {T.  M.  S.  1852,  p.  35)  : — "  It  may  be 
situated  in  any  part  of  the  zoospore  (XX.  35),  not  unfrequently  in  the  base, 
or  even  in  the  midst  of  one  or  other  of  the  bands  of  protoplasm  connecting  it 
with  its  neighbours  ;  it  is  pretty  uniform  in  size,  and  about  l-9000th  of  an 
inch  in  diameter."  Its  most  curious  property  is  its  rhythmical  contractility, 
its  pulsations  occurring  very  regularly  at  intervals  of  about  38"  to  41".  The 
contraction  is  rapid,  whilst  the  dilatation  is  gradual."  The  vesicle  "  would 
seem  to  exist,  or  at  all  events  to  present  a  contractile  property  only  for  a 
limited  period,  and  to  disappear  soon  after  the  formation  of  the  brown  spot," 
^.  e.  the  eye-speck.  The  coloiu"ed  eye-speck  or  stigma  lies  close  against 
the  primordial-ceU  wall,  it  is  not  invariably  present,  and  consequently  cannot 
be  esteemed  of  essential  importance  as  a  characteristic. 

The  wall  of  a  Volvo.vhas  an  appreciable  thickness,  represented  by  a  vertical 
section — in  fact  by  the  de23th  of  the  cells,  which  are  placed  side  by  side,  the 
lines  of  junction  being  straight  and  perpendicidar  to  the  external  siuface  of 
the  globe  (XX.  36).  The  inner  sides  of  the  cells,  bounding  the  internal  cavity 
of  the  globe,  are  somewhat  convex,  the  result  of  mutual  lateral  pressure,  and 
the  absence  of  centrifugal  pressure.  Prof.  Williamson  has  well  displayed 
this  by  sectional  diagrams  taken  from  his  preparations.  These  sectional  views 
also  demonstrate  the  position  of  the  rounded  masses  of  green  protoplasm — 
the  primordial  sacs — to  be  immediately  on  the  inside  of  the  peripheral  mem- 
brane or  envelope-cell  of  the  Volvo.v  (XX.  37,  38). 

Develojmient  of  Volvox. — Self-division  of  the  primordial  cells,  or  zoospores 
(Busk),  of  Volvox  is  regulated  by  the  same  laws  that  prevail  in  other  Volvo - 
cinece  and  in  other  imicellular  Algae  in  general.  Among  the  yoimger  speci- 
mens of  Volvox,  one  or  more  larger  globules  are  observable  (XX.  42-44),  which, 
if  watched,  will  be  found  to  undergo  segmentation,  fii^st  into  two  (XX.  42), 
then  into  foui'  portions  (XX.  43),  and  so  on  (XX.  46),  alwaj's  keeping  to  the 
power  of  two  and  its  multiples,  until  some  hundreds  of  minute  corpuscles  are 
developed  (XX.  47),  which,  according  to  the  nature  of  the  genus,  so  dispose 
themselves  in  a  lamina  as  to  enclose  a  hollow  spherical  space,  and  to  assume 
the  characteristic  globular  form.  Thus  a  new  Volvox  is  generated,  but  difi'er- 
ing  from  mature  forms  in  the  contiguity  of  its  component  individuals, — a  differ- 
ence, however,  which  progressively  vanishes  with  advancing  age.  The  young 
globe  lies  immediately  within  the  parent  being,  to  which  for  a  time  it  adheres, 
as  it  would  seem,  by  means  of  a  delicate  capsular  membrane,  within  which 
its  development  has  proceeded.  This  indeed  forms  its  sole  bond  of  union  with 
the  common  envelope  of  the  parent  Volvox  (XX.  33). 

When  first  formed,  the  cilia  of  the  primordial  cells  do  not  penetrate  through 
the  external  envelope  of  the  young  globe  :  however,  this  condition  is  of  short 
dui^ation  ;  for  no  sooner  is  the  detachment  from  the  wall  of  the  parent  about  to 
supervene,  than  the  cilia  protrude  externally,  and,  commencing  their  vibratile 
movements,  soon  set  the  newly-developed  colony  in  motion  within  the  cavity 
of  its  parent.  The  detachment  is  consequent  on  the  rupture  of  the  investing 
capsule,  caused,  no  doubt,  by  the  constantly  enlarging  bulk  of  the  young 


OF  THE  THYTOZOA.  183 

organisms.  Constantly  several  young  colonics  are  developed  from  the  parent 
at  the  same  time,  or  nearly  so,  by  the  self-fi>ssion  of  various  primordial  cells ; 
hence,  as  a  rule,  a  brood  of  young  globes  is  to  be  seen  revolving  ^^ithin  the 
parent  sphere  (XX.  33),  from  which  ere  long  it  is  released  by  its  rupture. 

The  condition  of  the  individual  cells  of  a  young  Volvox  has  akeady  been 
mentioned, — viz.  their  close  apposition  at  first,  their  gradual  separation  by  an 
interval,  the  appearance  of  radiating  processes  from  the  protoplasm,  and  their 
progressive  attenuation.  To  this  account  we  may  add  that  contiguous  inter- 
current processes,  in  their  earher  stages,  appear  to  coalesce, — a  circumstance 
which  indicates  that  the  protoplasm  is  then  unenclosed  by  a  pellicle  or  envelope. 
Again,  the  protoplasm  gradually  contracts  itself  into  its  flask-shape,  the  retrac- 
tion and  coalescence  of  its  processes  being  a  simultaneous  phenomenon ;  indeed 
contraction  of  the  protoplasmic  globules  advances  continuously  until,  as  in  old 
specimens,  only  a  small  rounded  mass  appears  in  the  centre  of  a  large  clear 
space.  Lastly,  the  coloured  stigma  is  an  after- production ;  and  its  advent 
would  seem  to  indicate  the  maturity  of  the  cell. 

Analogy  with  other  Volvocinece  would  lead  us  to  look  for  a  quiescent  or 
^'  still "  stage  of  the  cells  of  Volvo.v,  and  the  formation  of  microgonidia,  in 
addition  to  the  process  described,  viz.  multiplication  by  self-division  with 
the  production  of  macrogonidia.  That  a  ''  still "  form  actually  occurs  is 
pretty  clearly  shown  by  Mr.  Busk's  observations  of  Volvox  aureus,  from 
which  this  presumed  species  appears  to  be  nothing  more  than  Volvox  glo- 
hator,  having  a  vaiying  number  of  its  cells  encysted  to  form  the  winter  or 
'■resting"  spores.  The  primordial  cells  which  are  to  undergo  this  change 
are  at  first  indistinguishable  fi^om  the  ordinary  ones,  except  in  having  a 
deeper  green  colour  {Bv£c,  op.  cit.  p.  38).  Afterwards,  however,  they  ac- 
quii^e  a  thick  wall,  change  to  a  yellow  colour  (hence  the  appellation  aureus, 
golden  or  yellow),  without  material  alteration  of  size,  and  produce  a  second 
equally  fiim  and  distinct  envelope ;  or  rather,  it  may  be,  the  original  cells 
contract  somewhat,  and  then  form  a  second  coat  around  themselves.  Even- 
tually a  considerable  space  exists  between  these  two  coats,  occupied  by  a 
clear  and  apparently  aqueous  fluid ;  but  upon  the  addition  of  a  solution  of 
iodine,  a  granular  cloudiness  is  produced  in  it.  The  contents  of  the  inner 
cell  consist  chiefly  of  amylaceous  grains,  mixed  with  a  greenish  material  in 
the  one  case,  and  with  a  bright  yellow,  apparently  oily  fluid  in  the  other. 
The  amylaceous  particles  are  of  an  irregular  botryoidal  form,  and  far  from 
uniform  in  size. 

Mr.  Currey,  in  a  recent  interesting  communication  on  fresh-water  AlgSB 
(J.  M.  S.  1858,  p.  208),  states  that  he  has  seen  "  one  of  the  large,  orange- 
coloured  spores  of  the  so-called  V.  aureus,  which  is  only  the  resting  form  of 
F.  glohator,  where  the  contents  divided  into  five  globular  colourless  cells, 
which  floated  in  a  mass  of  reddish  plasma,  being  apparently  the  remains  of 
so  much  of  the  original  contents  of  the  cell  as  had  not  been  absorbed  in  the 
formation  of  the  secondary  cells." 

Of  the  Volvox  steUatus,  Mr.  Busk  adds  that  it  seems  to  him  merely  a  modi- 
fication of  V.  aureus,  and  appears  to  follow  the  same  course  of  change,  and 
doubtless  of  future  development.  With  these  conclusions  Prof.  Williamson 
coincides,  and  remarks  (oj).  cit.  p.  56)  that  "  the  ordinary  power  of  gemma- 
tion in  V.  steUatus  appears  to  have  worn  itself  out,  since,  though  the  gemmae 
often  exist  with  the  spores  (?),  they  are  small,  coloiuiess,  and  abortive." 

It  must  also  be  mentioned  that  Perty  suggests  an  analogous  interpretation 
of  the  nature  of  Volvox  aureus,  and  doubts  hkewise  the  specific  importance 
of  V.  SteUatus. 

8ince  the  above  remarks  were  penned,  Cohn's  researches  on  Volvox  glohator 


184  GENEEAL  HISTOHY  OF  THE  liS^FUSORIA. 

have  determined  the  reality  of  another  mode  of  reproduction  besides  fission, 
as  surmised  (Ann.  Sc.  Nat.  and  Comptes  Rendus,  1856).  The  abstract  of 
this  most  interesting  paper  is  translated  in  the  J.  M.  S.  1857,  p.  149  : — "  The 
second  mode  of  reproduction  of  Volvox  requii'es  a  sexual  conjunction,  and  is 
not  observed  indifferently  in  all  indi^dduals.  The  sj)herules  endowed  with 
the  sexual  fimction  are  distinguished  by  their  volimie  and  the  more  consi- 
derable number  of  their  component  utiicles  :  they  are  generally  monoecious  ; 
that  is  to  say,  they  enclose  at  the  same  time  male  and  female  cells,  although 
the  majority  of  their  contents  are  neuter.  The  female  cells  soon  exceed  their 
neighboui's  in  size,  assume  a  deeper  green  colom-,  and  become  elongated  like 
a  matrass  towards  the  centre  of  the  Volvox.  The  endochrome  of  these  ceUs 
does  not  undergo  fission.  In  other  cells,  on  the  contrary,  which  acquire  the 
size  and  form  of  the  female  ceUs,  the  green  plasma  may  be  seen  to  divide 
symmetrically  into  an  infinity  of  very  minute  particles,  or  linear  corpuscles, 
associated  into  discoid  bundles.  These  are  fiu'iiished  with  ^ibratile  cilia,  and 
oscillate  at  fii^st  slowly  in  their  prism  ;  but  the  movement  soon  becomes  more 
active,  and  the  bundles  speedily  break  up  into  theu^  constituent  elements. 
The  fi'ee  corpuscles  are  very  agile,  and  it  is  impossible  to  regard  them  as  any- 
thing but  true  spermatozoids  ;  they  arc  linear  and  thickened  at  the  posterior 
extremity ;  two  long  ciha  are  placed  behind  theii^  middle,  and  the  rostrum, 
which  is  curved  like  the  neck  of  a  swan,  possesses  sufficient  contractility  to 
execute  the  most  varied  movements.  These  spermatozoids,  so  soon  as  they 
are  they  are  able  to  disperse  themselves  in  the  cavity  of  the  Volvox,  quickly 
crowd  aroimd  the  female  cells,  into  which  they  eventually  penetrate  ;  arrived 
there,  they  attach  themselves  by  the  beak  to  the  plastic  globule,  destined  in 
each  ceU  to  form  a  spore,  and  with  which  they  are  gradually  incoi-porated. 
Fecundation  having  been  thus  effected,  the  reproductive  globule  becomes  enve- 
loped successively  by  an  integument  exhibiting  conical  pointed  eminences,  and 
by  an  interior  smooth  membrane ;  the  chlorophyll  which  it  contained  is  now 
replaced  by  starch  grains,  and  a  red  or  orange-coloiu-ed  oil.  This  is  the  con- 
dition of  the  spore  at  matmity ;  and  occasionally  forty  of  these  bodies  may  be 
counted  in  a  single  globe  of  Volvox.  The  germination  of  these  reproductive 
bodies  has  not  yet  been  observed,  so  that  their  history  cannot  be  regarded  as 
complete ;  but  from  analogy  it  may  in  the  meanwhile  be  assumed  that  they 
germinate  in  the  same  way  as  do  the  spores  of  (Edogonmm,  Splueroplea,  and 
other  Algae  belonging  to  the  same  order.  It  may  be  maintained,  moreover, 
as  certain  that  the  Splicerosira  volvox,  Ehr.,is  nothing  else  than  a  monoecious 
Volvox  glohator ;  that  his  Volvox  stellatm  is  also  V.  glohator,  obseiwed  at  the 
time  when  it  is  filled  with  stellate  spores ;  and  lastly,  that  his  V.  aureus 
differs  from  the  other  forms  of  the  same  species,  simply  in  the  smooth  [and 
coloured]  condition  of  the  spores;" 

FAMILY  lY.— YIBRIONIA. 
(Plate  XYIII.  57  to  69.) 

This  family  foUows,  in  Ehrenbei'g's  system,  the  VolvocinecB ;  yet,  by  reason 
of  the  extreme  simplicity  of  stmcture  of  the  beings  composing  it,  it  should,  in 
any  attempted  natiu'al  system,  be  placed  even  below  the  Monadina. 

The  distinguished  author  of  the  Infuslonstluerclien  attributed  an  animal 
nature  to  the  Vihrionia,Q.Tidi  although  obliged  to  confess  his  inability  to  detect 
any  internal  organization,  nevertheless  argued,  from  analogy,  that  a  polygas- 
tric  structui-e  was  to  be  presumed,  and  that  their  movements  were  voluntary, 
and  of  themselves  sufficient  proof  of  animaHty.  In  Bacterium  triloculare, 
indeed,  Ehrenberg  believed  he  saw  an  internal  granidar  ova-mass,  a  vibratile 


OF  THE  PHYTOZOA.  185 

filament,  and  spontaneous  fission.  Of  the  Vihrionia  generally,  he  stated  that 
they  were  unable  to  change  the  form  of  their  body,  although  without  lorica, 
and  that  by  imperfect  self-division  they  formed  chains  or  concatenated  fila- 
ments, which  in  S_pirillum,  from  the  obhquity  of  the  junction-siufaces  of  the 
component  Vibrios,  assume  a  spiral  form. 

Yarious  later  writers,  among  whom  are  Leuckhart,  Cohn,  and  Burnett, 
would  transfer  the  Vihrionia  to  the  vegetable  kingdom.  The  last-named 
author  contributed  a  valuable  paper  to  the  American  Association  in  1850 ; 
but  the  most  recent  examination  of  the  nature  and  structure  of  the  beings  in 
question  is  from  the  able  pen  of  Dr.  Cohn  (Entw.).  "We  must  also  mention 
that  Perty  has  given  considerable  attention  to  the  Vihrionia,  and  contributed 
some  original  observations.  It  is  to  Cohn's  account,  however,  that  we  shall 
chiefly  resort  in  oiu'  attempt  to  describe  the  minute  and  ciuious  members  of 
this  family,  which,  if  not  rich  in  genera,  is  unsurpassed  by  any  in  the  abun- 
dance and  diffiision  of  its  members. 

Some  natiu'alists  have  considered  the  Vihrionia  to  be  the  active  agents  in 
producing  putrefaction,  since  they  are  invariably  found  in  decomposing  fluids, 
just  as  the  yeast-plant  (Torida)  always  occurs  in  fermenting  saccharine  mat- 
tei*s  and  appears  to  excite  the  process  of  fermentation. 

The  Vihrionia  are  for  the  most  part  colourless ;  imder  certain  conditions, 
however,  they  assume  a  yellow,  red,  or  a  blue  tint,  but  never  a  green  colour'. 
Their  movements,  says  Perty,  are  rapid  and  energetic,  so  much  so  that  the 
corpuscles  of  Hysginum  nivale,  although  at  least  one  thousand  times  larger, 
are  thinst  aside  by  Bacterium  Termo  when  in  motion.  They  can  advance 
with  either  end  forward  with  equal  facihty,  and  mostly  seem,  after  proceed- 
ing a  certain  distance,  to  retrace  their  course  to  the  point  they  started  from. 

The  extreme  minuteness  of  some  Vihrionia  may  be  conceived  from  the 
statement  of  Perty,  that,  according  to  his  calculation,  four  thousand  millions 
occupy  no  more  space  than  one  cubic  line. 

Dujardin,  who  retains  the  Vihrionia  among  animalcules,  makes  the  follow- 
ing remarks  : — "  The  Vihrionia  are  the  first  Infusoria  which  present  them- 
selves in  aU  infusions,  and  which  from  their  extreme  smallness,  and  the  im- 
perfection of  our  means  of  observation,  must  be  considered  the  most  simple ; 

for  it  is  only  their  more  or  less  active  movements  which  lead  to  their 

being  regarded  as  animals  at  all.  I  have  been  sometimes  induced  to  beheve 
that  there  is  a  flageUiform  filament,  analogous  to  that  of  monads,  or  rather 
perhaps  a  spiral  undulating  one,  which  produces  the  peculiar  mode  of  loco- 
motion. Is  the  Bacterium  triloculare,  described  by  Ehrenberg  as  having  a 
proboscis,  a  true  Vihno  ? 

"  AU  that  can  be  with  certainty  predicated  respecting  their  organization  is 
•that  they  are  contractile,  and  propagate  by  spontaneous  fission,  often  imper- 
fect in  character,  and  hence  give  rise  to  chains  of  greater  or  less  length." 

Cohn  modestly  premises  {Entw.  p.  118)  that  his  researches  have  been  di- 
rected chiefly  to  one  species  ;  yet,  from  scattered  observations,  and  fi^om  pre- 
sumptive evidence,  he  would  assign  a  vegetable  nature  to  aU  the  species. 

In  decomposing  infusions,  often  after  a  few  hours,  extremely  minute 
corpuscles  may  be  seen  in  countless  number,  having  the  figm^e  of  a  dot  or 
comma,  or  of  very  delicate  hues  with  the  ends  somewhat  thickened.  Their 
motion  is  tolerably  active,  darting  hither  and  thither,  contorting  themselves 
at  the  same  time  by  a  rotating  movement  upon  their  long  axis,  and,  when  in 
masses,  produce  the  appearance  of  a  ceaseless  swarming,  in  which  the  indi- 
vidual specks  are  easily  overlooked  on  account  of  their  smallness.  They, 
however,  differ  in  size  among  themselves,  varying  from  1-2000  to  1-700'"  in 
length.     Ehrenberg  attributed  to  this  world-wide  form  the  name  of  Vibrio 


186  GENERAL  HISTOtlY  OF  THE  INFUSORIA. 

lineola,  whilst  Dujardin  more  correctly  separated  it  from  the  Vibrios  under 
the  name  of  Bacterium  Teryno.  Under  this  latter  appellation  Perty  has  also 
described  it. 

Now  when  we  come  to  examine  an  infusion  rich  in  these  organisms,  nu- 
merous jelly-like  colourless  masses  of  different  size  and  figure  (XVIII.  69) 
may  be  met  with  on  the  waUs  of  the  vessel,  and  on  the  surface  of  the  fluid. 
These  when  young  resemble  small  balls,  fi^om  1-100'"  and  less  in  diameter; 
but  as  they  continue  constantly  to  enlarge,  they  acquii-e  a  clustered  outline, 
and  exhibit  themselves  as  colourless  masses  and  films  of  very  considerable 
superficial  dimensions  and  thickness,  resembling  soft  Palmellse  in  consistence. 
Like  these  they  are  composed  of  a  transparent  mucus,  in  which  numberless 
punctate  or  linear  corpuscles  are  imbedded.  These  last  are  identical  with 
the  isolated  particles  known  as  Bacterium  Termo.  That  these  corpuscles  are 
held  together  by  the  common  mucus,  is  evident  to  the  eye ;  even  the  largest 
films  are  also  composed  of  globular  clusters  agglomerated  together,  the  out- 
line of  the  gelatinous  mass  appearing  sharply  defined  in  the  water.  More- 
over, the  linear  corpuscles  appear  more  thickly  congregated  at  the  periphery 
than  in  the  centre  of  the  spherical  collections ;  but  this  is  an  optical  delusion. 
Again,  when  coloiu'ing  matter  is  added  to  the  water,  the  Bacterium-TmiQ.ws>  is 
not  tinged  by  it ;  and  when  any  passing  Infusorium  impinges  against  it,  its 
surface  is  pressed  in ;  and  lastly,  the  absence  of  an  independent  and  inherent 
molecular  motion  among  the  particles  show  them  to  be  enclosed  within  a  re- 
sistant medium.  Frequently,  whilst  under  observation,  single  corpuscles  may 
be  seen  to  detach  themselves  and  swim  away  in  the  characteristic  manner. 

The  definite  outline  and  figure  of  the  mucilaginous  globules,  and  of  their 
clusters,  refute  the  notion  that  such  are  merely  collections  of  dead  Bacterium- 
corpuscles.  The  indication  is  rather  that  the  Pahnella-V^^e  masses  represent 
the  young  condition  of  Bacterium;  indeed,  the  same  cycle  of  development 
proceeds  as  in  PahneUa,  Tetraspora,  and  allied  forms ....  The  only  difference 
betwixt  the  J5ac^^rn«)i-heaps  and  Palmella-  or  Tetraspora-va^^^Q^  is,  that  in 
the  first  the  individual  corpuscles  are  so  minute  that  the  characters  of  simple 
cells  cannot  confidently  be  assigned  them,  and  that,  instead  of  being  yellow 
or  light  green,  they  are  quite  coloui4ess.  Nevertheless,  in  Kiitzing's  Palmella 
Brehissonii  and  P.  hyalhia,  the  cells  are  only  1-3000  to  1-1000'"  in  length, 
whilst  their  figure  and  distribution  are  indistinguishable  from  Bacterium.  The 
absence  of  colour  is  a  feature  of  the  Pungi  connected  with  their  occiuTence 
in  decomposing  infusions  ;  yet  Palmella  hyalina  has  only  a  pale  ochreous  hue, 
and  Cohn  seems  to  satisfactorily  establish  that  the  mere  presence  or  absence 
of  coloiu'  cannot  constitute  that  decisive  character  which  the  separation  of 
the  microscopic  Fungi  from  the  Alg^e  implies. 

From  the  above  it  appears  evident  that  the  corpuscles  known  as  Bacterium 
Termo  are  the  swarm-cells  (zoospores)  of  a  plant  aUied  to  Palmella  and  Te- 
traspora, but  referable,  by  reason  of  the  want  of  coloui%  to  the  microscopical 
aquatic  Fungi.  When  these  Vibrios  pass  into  a  state  of  rest,  they  accumu- 
late on  the  sm^ace  of  the  water  in  the  form  of  films,  &c.,  as  do  the  resting- 
spores  of  Tetraspora,  Stigeoclinium,  Conferva,  and  other  Algse,  but,  unHke 
these,  are  connected  together  by  an  intercellular  substance,  within  which 
their  growth  proceeds,  and  leads  frequently,  as  Perty  has  illustrated,  to  theu' 
disposal  in  linear  branching  series. 

From  the  analogy  mth  Tetraspora  and  the  other  swarm-cells  of  Algee  and 
Fungi,  it  must  be  assumed  that  the  Bacterium-corpuscles  move  by  means  of 
a  vibratile  fibre ;  indeed  Ehrenberg  intimates  having  seen  a  filament  in 
Bacterium  triloculare,  and  Dujardin  considered  some  such  mechanism  pro- 
bable. 


OF  THE  PHYTOZOA.  187 

The  growth  of  the  mucous  balls  is  the  consequence  of  the  constantly  re- 
peated transverse  fission  of  the  Bacterium-hodies,  and  is  exceedingly  raj)id. 
Yon  Flotow  seems  to  have  detected  the  compoimd  masses,  and  named  one 
such  Microhaloa  teres ;  but  Cohn  finds  it  necessary  to  create  a  new  genus, 
which  he  has  named  Zooglma. 

Of  the  remaining  Vibrios,  Cohn  has  not  as  yet  complete  researches ;  yet  he 
finds  sufficient  support  from  analogy  to  warrant  him  in  assuming  a  like  history 
for  them  as  for  ZooyJoea.  The  larger  forms  of  Vibrio  have  (he  says)  a  striking 
affinity  with  the  OsciUarice,  whilst  the  longer,  slowly-moving  species  have  a 
very  great  likeness  to  the  shorter  fibres  of  Hyyrocrocis,  from  which,  some  have 
stated,  Vibrios  derived  their  origin.  The  affinity  of  Vihyno  with  the  colour- 
less OsciUarice — mth  the  genus  Beggiatoa,  in  which  also  very  delicate  forms 
occiu' — may  be  especially  pointed  out ;  but  this  affinity  is  yet  more  striking 
with  SpiriUmn  and  Spirocliceta,  the  other  two  genera  of  Vibrioma.  Fiu-ther, 
in  Oscillarieae  we  meet  with  straight  species,  e.  g.  OsciUaria,  and  spirally 
convoluted  forms,  e.  g.  Spirulina,  just  as  we  have  straight  forms  in  Vibrio, 
and  spirally-tmsted  ones  in  Spirillum  and  Sjnrochceta.  Likewise,  on  com- 
paring the  movements  of  Spirochceta  w^th  those  of  Spirulina,  we  find  no  dis- 
tinction between  them  except  in  energy  and  livehness. 

The  results  of  his  examination  of  Vibrionia  are  thus  summarily  stated  by 
Cohn  (p.  130)  :— 

"1.  The  Vibrionia  apparently  all  belong  to  the  vegetable  kingdom ;  for  they 
•exhibit  an  intimate  affinity  with  undoubted  Algae. 

"  2.  By  reason  of  their  want  of  colour,  and  their  occiu-rence  in  decomposing 
infusions,  the  Vibrionia  belong  to  the  group  of  aquatic  fungi  {MijcopJiycece)^ 
Cohn,  however,  shows  good  reason  for  not  admitting  this  as  a  natiu'al  group 
distinct  from  Algge. 

"  3.  Bacterium  Termo  is  the  motile  swarming-phase  of  a  genus,  Zooglcea, 
allied  with  Palmella  and  Tetraspora. 

"  4.  Spirochceta  plicatilis  belongs  to  the  genus  Spirulina,  of  which  it  must 
be  at  once  admitted  as  a  species  (^Spirulina  plicatilis). 

"5.  The  long  Vibrios  which  do  not  coil  (Vibrio  Bacillus)  arrange  them- 
selves Avith  the  more  delicate  forms  of  Beggiatoa  (OsciUaria). 

^'  6.  The  shorter  Vibrios  and  SpiriUce  resemble  indeed,  in  form  and  charac- 
ter of  motion,  the  OsciUarice  and  Spiruliyice ;  nevertheless  I  cannot  positively 
decide  on  their  true  natui'e." 

To  this  abstract  of  Cohn's  paper  on  Vibrionia  we  must  add  a  notice  of 
Dr.  Burnett's  essay,  which  is  equally  in  favour  of  their  plant-Hke  natui'e. 
The  chief  observations  and  opinions  of  Dr.  Burnett  are — that  a  branching  of 
the  chains,  similar  to  that  of  the  ordinary  forms  of  Algae,  is  observable  in 
Vibrionia,  particularly  in  Spirillum;  that,  on  watching  their  gradual  growth, 
the  smaller  seem  no  other  than  the  younger  forms  of  larger  species  (for  in- 
stance, that  Vibrio  is  the  first  condition  under  which  Bacterium  and  Sp>i- 
rillmn  appear)  ;  thaf  besides  self-di\ision,  propagation  is  effected  by  budding, 
a  fact  fu]-ther  exemplified  by  the  occuiTcnce  of  ramifications ;  and  that  in 
yoimg  forms  a  nucleus  is  absent,  although  one  becomes  apparent  in  advanced 
stages.  Again,  as  to  the  movements  of  Vibrionia,  Dr.  Biu-nett  can  see  no 
fiu'ther  indication  of  movement  in  them  than  in  spermatozoa  and  in  vegetable 
cells,  like  which  they  are  imaffected  by  electrical  shocks,  which  are  fatal  to 
the  lower  forms  of  animal  life. 

''  Their  cell- structure  and  their  vital  (not  voluntary)  motion  would  then 
lead  us  to  infer  that  the  Vibrionia  are  Algous  plants,  and  not  animals.  This 
throws  light  on  several  common  phenomena.  One  in  particular  is,  that  the 
Vibrionia  should  almost  invariably  be  found  in  infusions  and  liquids  that 


188  GENEEAL  HISTORY  OF  THE  INTUSOEIA. 

contain  other  Algae,  and  especially  the  common  Torula;  for  I  do  not  re- 
member to  have  seen  the  Torula  without  Vibrionia.^' 

Perty  moreover  testifies  to  Vibrio  Bacillus  assuming  a  still  condition,  and, 
by  its  branching  concatenation,  a  plant-like  form,  out  of  which  are  constructed 
masses  and  films  in  the  infusion  and  upon  its  surface,  resembling  Hygro- 
crocis  and  other  Algae  and  aquatic  Fungi. 

Dr.  Ayres  {J.  M.  S.  i.  p.  301)  contributes  the  following  obsei^vations  on 
the  self-division  of  the  Vib/ioma  : — "  A\Tiile,"  he  writes,  "  the  shortest  of  the 
Vibriones  were  in  active  motion,  the  longer  ones  were  comparatively  quies- 
cent ;  and  these  exhibited,  according  to  their  length,  from  one  to  six  trans- 
verse lines,  indicating  the  points  of  separation  in  the  reproductive  process. 
Those  of  moderate  length,  presenting  only  one  or  two  transverse  hnes,  were 
rather  active,  and  often  bent  at  an  angle  at  the  transverse  lines,  which  pre- 
sented the  appearance  of  separation  into  two  distinct  indi\iduals ;  and  the 
character  of  the  movements  appeared  such  as  to  favour  the  separation.  Those 
with  fi'om  three  to  six  transverse  lines  were,  for  the  most  part,  quiescent. 
I  imagined,  although  from  their  excessive  minuteness  and  transparency  this 
was  not  plainly  and  unequivocally  discernible,  that  there  were  indentations 
of  the  extremities  of  the  transverse  Hnes,  by  which  constrictions  were  pro- 
duced, which,  by  their  increase,  would  finally  efi'ect  a  complete  transverse 
division  of  the  animals." 

The  occurrence  of  Vibrios,  or  at  least  of  Vibrio-]jke  forms,  as  one  of  the 
metamorphic  phases  of  the  Pliytozoa  of  the  antheridia  of  Characece,  e.g. 
Marchantia,  has  been  mentioned  in  a  foregoing  page  (126),  to  which  we 
must  refer  our  readers. 

FAMILY  v.— ASTASI^A  OE  EUGLEN^A. 
(Plate  XYIII.  36—50,  62,  53,  55,  m.) 

Dujardin  very  properly  prefers  to  caU  this  group  Euglencea  {Eugleniens),  on 
account  of  the  resemblance  in  sound  of  the  fii^st  name  with  that  of  Astacicea 
(Astaciens)  used  to  designate  a  family  of  the  higher  Crustacea. 

In  Ehrenberg's  system  it  constituted  a  family  of  the  Polygastrica,  and  was 
characterized  by  wanting  a  tnie  alimentary  canal,  a  lorica  and  appendages, 
and  by  having  a  mouth  sm^mounted  by  one  or  two  proboscides,  and  in  most 
species  by  a  changeable  form.  Internally,  digestive  sacs,  ova,  a  seminal  gland, 
and  contractile  vesicle,  and  in  most  genera  one  or  more  red  specks  or  eyes, 
were  represented  as  present.  The  genera  included  were — Astasia,  Ambly- 
oj)his,  Euglena,  Chlorogonium,  Colacium,  and  Distigma.  The  value  of  these 
genera  has  been  called  in  question  by  various  wiiters.  Dujardin  makes  the 
variability  of  form — in  other  words,  a  contractile  integument — a  leading  fea- 
ture, and  rejects  the  eye-speck  as  neither  distinctive  nor  constant ;  conse- 
quently he  excludes  from  the  family  the  EugUnce  with  rigid  integument, 
and  transplants  them  to  the  Thecamonadina,  and  rearranges  the  remaining 
species  according  to  the  number,  disposition,  and  character  of  theii'  locomo- 
tive filaments.  Likewise  Schneider  (A.  iV.  H.  1854,  xiv.  p.  327)  separates 
Chlorogonium  from  the  Astasia^a  because  of  its  unchangeable  figure ;  and 
Mr.  Carter  {A.  N.  H.  1856,  xviii.  p.  116)  would  also  detach  Astasia  from  Eu- 
glena, from  the  conviction  that  the  former  has  an  animal  organization,  and 
that  the  latter  is  referable  to  plants. 

In  the  follo^ving  general  history  of  the  Astasicea,  our  descnption  will 
chiefly  apply  to  the  two  genera  Astasia  and  Euglena,  respecting  which  we 
have  very  copious  details  in  the  papers  by  Mr.  Carter,  (A.  N.  H.  1856,  xviii.). 


OF  THE  PnXTOZOA.  189 

Of  the  remaining  genera,  some  comparative  observations  \\dll  be  made  in  pass- 
ing, and  particular  researches  respecting  them  added  from  Perty  and  other 
inquirers. 

EufjJence  and  Astasice  are  mostly  spindle-shaped  (fusifomi),  and  give  off 
from  theii'  anterior  extremity  one  or  two  delicate  filaments,  and  posteriorly 
a  usually  short  blunt  tail.  Excluding  the  doubtful  Euglenece,  which,  on 
account  of  their  rigid  integument,  we  think,  mth  Dujardin,  should  be 
transferred  to  another  family,  the  remaining  species  of  the  two  genera 
in  question  are,  from  their  inherent  contractility,  capable  of  varying  their 
form  to  a  remarkable  extent;  i.e.,  to  use  a  technical  word,  they  are  " meta- 
holicJ^  This  property  is,  nevertheless,  much  more  restricted  than  in  the 
Amcebce ;  for  the  Astasicea  can  send  off  no  oifshoots  or  variable  processes 
like  those  animalcules,  but  in  all  their  manifold  contortions,  elongations, 
and  contractions  do  not  completely  lose  theii'  primitive  figure.  In  general, 
the  recurrence  of  the  changes  of  figure  is  quite  arbitrary  and  without  regu- 
larity. In  Eutre])tia  viridis  and  Astasia  margaritifera,  however,  Perty 
represents  an  alternate  or  peristaltic  expansion  and  contraction  of  the  or- 
ganism, so  that  first  the  anterior  and  then  the  posterior  extremity  expands. 
He  adds,  besides,  that  in  this  Astasia  the  contained  clear  globules  are  not 
transferred  backwards  and  forwards,  but  only  a  fluid  matter  which  runs  in 
channels  between  them. 

The  Astasicea  are  covered  by  a  distinct  flexible  and  elastic  envelope, 
which  ]\Ii\  Carter  calls  the  "  pellicle,"  and  states  that  it  resembles  the  cover- 
ing of  Amcehce,  is  stnictiu'eless,  and  hardens  after  secretion.  Stein  also 
afRi-ms  that  in  Euglena  it  is  similar  to  the  enclosing  membrane  of  Grvegarina, 
and,  like  it,  a  shut  sac  without  mouth  or  other  aperture.  On  the  contrary, 
the  translator  of  Kolliker's  paper  on  Actinophrys  (J.  M.  S.  i.  p.  100,  note) 
denies  the  existence  of  a  distinct  envelope  to  this  genus.  Beneath  the 
peUicle,  adds  Mr.  Carter,  is  a  transparent  moving  substance,  with  an  inhe- 
rent property  of  contractility  and  polymor})hism,  which  proves  itself  inde- 
pendent of  the  superposed  pelhcle  when,  in  the  process  of  encysting,  the  two 
become  separated :  this  substance  is  the  "  diaplianey 

Enclosed  within  these  laminae  are  the  contents,  consisting  of  a  proto- 
plasmic matter  with  suspended  particles  and  certain  definite  structures,  viz. 
a  nucleus  and  contractile  vesicle  (XYIII.  46  «,  c).  The  protoplasm  is  the 
same  matter  Dujardin  names  the  "  sarcode,"  and  is  occupied  with  a  varying 
quantity  of  corpuscles,  diff'ering  among  themselves  in  size,  and  imparting  the 
colour  peculiar  to  the  species. 

"  In  Euglena,^^  writes  Mr.  Carter  {op.  cit.  p.  119),  "  the  sarcode  is  separated 
from  the  diaphane  by  a  layer  of  pointed  sigmoid  fibres,  arranged  parallel  to 
each  other,  so  as  to  fonn  in  Cnimemda  texta  (Duj.)  a  conical  cell,  which,  so 
soon  as  the  ovules  have  become  developed,  and  the  diaphane  and  other  con- 
tents of  the  sarcode  have  died  off,  becomes  transparent,  although  it  still 
retains  its  conical  form  until  the  resiliency  of  the  fibres,  now  unrestrained 
by  the  diaphane  and  other  soft  parts,  causes  dehiscence,  and  sets  the  ovules 
at  Uberty." 

These  fibres  are  therefore  the  cause  of  the  spiral  markings  of  several 
Emjhnce,  as  well  as  of  Phacus  and  Chonemonas ;  they  are  strongly  marked 
in  Euglena  spirogijra.  "  In  another  specimen  of  Euglena,^'  says  Perty  (p.  57), 
"  of  fully  a  sixth  of  a  line  in  length,  and  of  a  grass-green  coloiu%  some  thirty 
dehcate  longitudinal  lines  were  perceptible,  which,  when  the  body  turned  on 
itself,  looked  as  if  spii-ally  disposed.  Moreover,  on  examining  Lepocinclis- 
globules  wheu  partially  diied,  the  spiral  lines  appear  composed  of  rows  of 
closely  aiTanged  dots  " — a  phenomenon  probably  explicable  on  the  supposi- 


190  GENERAL  HISTORY  OF  THE  INFUSORIA. 

tion  that  the  fibres,  as  a  consequence  of  evaporation,  have  been  broken  up 
into  particles  by  the  act  of  diffluence. 

Mr.  Carter  distinguishes  certain  minute  colouiiess  granules  diffused  in 
the  general  protoplasm  of  the  interior,  which  he  specially  designates  "  mole- 
cules." These,  says  this  obseiTer,  are  the  first  to  appear  in  the  homogeneous 
sarcode,  but  afterwards  become  intermixed  ^vith  larger  corpuscles — "  gra- 
nules"—  and  with  "  ovules  ;"  and  by  the  time  the  o\Tiles  have  become  fully 
formed,  the  sarcode  and  its  molecules  have  dried  off  or  disappeared,  "  More- 
over, in  Astasia,  digestive  globules  also  appear ;  but  here  the  food  is  taken 
in  through  a  distinct  mouth,  while  in  Euglena  the  absence  of  such  vesicles 
would  appear  to  indicate  that  its  suj^port  is  of  a  different  kind,  if  not  intro- 
duced in  a  different  way." 

Ehrenberg  noted  the  existence  of  a  contractile  vesicle  at  the  anterior  ex- 
tremity of  Euglena ;  the  like  is  also  seen  in  Astasia  ;  but  in  neither  instance 
have  its  pulsations  been  directly  obsei^ed.  A  nucleus  is  also  present  of  a 
discoid  shape,  and  siuToimded,  according  to  Mr.  Carter,  by  a  transparent 
capsule,  which  appears  like  a  narrow  pellucid  ring  aroimd  it,  owing  to  its 
greater  size.  In  Chlorogonium  and  Amhhiopliis,  Ehrenberg  encoimtered 
what  he  called  a  seminal  gland,  i.e.  a  nucleus,  and,  in  the  latter  genus,  men- 
tions the  presence  of  two  wand-hke  bodies  in  front  and  three  behind  it. 
Thirteen  such  peculiar  structiu'es  were  also  seen  by  Perty  in  a  large  specimen 
of  Euglena  sjyirogyra,  which  he  concluded  had  originated  from  a  peculiar 
disposition  of  the  internal  substance.  The  same  ambiguous  structures  are 
doubtless  referred  to  in  the  following  paragi^aph  by  Mr.  Carter,  although, 
indeed,  structm-al  pecuharities  are  detailed  which  would  render  Perty's  ex- 
planation inadmissible  unless  qualified  in  some  measure  {A.  N.  H.  1856, 
xviii.  p.  241): — ''With  reference  to  the  single,  glaiiy,  capsuled  body  which 
exists  in  the  centre  of  Phacus  and  in  the  large  lip  of  Crumemda  texta,  also 
dually  in  Euglena  geniculata,  Duj.  {Spirogyra,  Ehr.),  on  each  side  the  nu- 
cleus, I  can  state  nothing  further  than  that  in  the  two  first  it  consists  of 
a  discoid  transparent  capsule,  which  at  an  early  stage  appears  to  be  filled 
with  a  refractive,  oily-looking  matter ;  that  it  is  fixed  in  a  particular  posi- 
tion, and  remains  there  apparently  imaltered,  with  the  exception  of  becoming 
nucleated,  until  every  part  of  the  animalcule  has  perished,  and  nothing  is 
left  but  the  spiral-fibre  coat,  and  perhaps  a  few  o^iiles.  In  Euglena  geniculata 
it  is  bacilliform,  and  contains  a  correspondingly-shaped  nucleus;  and  al- 
though I  can  state  nothing  respecting  its  uses,  I  cannot  fail  to  see  that  it 
has  an  interesting  analogy,  particularly  in  the  latter  instance,  T\dth  two 
similar  organs  which  are  commonly  seen  in  the  Navicula,  and  which  in 
N.  fulva,  e.g.,  are  situated  in  a  variable  position  between  the  nucleus  and 
the  extremities  on  either  side." 

The  numerous  globules  diffused  thi^oughout  the  body,  which,  in  addition  to 
the  foregoing,  make  up  the  contents  of  the  Astasicea,  and  according  to 
Ehrenberg  are  to  be  considered  ova,  have,  after  being  denied  that  nature 
by  Dujardin  and  others,  been  again  brought  to  notice  under  the  name  of 
ovules  or  germ-cells  by  Perty  and  Carter.  They  are,  in  the  words  of  the 
latter  observer  (p.  223),  nucleated  cells,  which,  at  an  early  stage,  "  consist  of 
a  transparent  capsule  lined  with  a  faint  yellow  film  of  semi-ti'ansparent 
matter,  which  subsequently  becoming  more  opaque  and  yellowish,  also  be- 
comes more  marginated  and  distinct,  and  assumes  a  nucleolar  form.".  .  .  . 
"  In  the  discoid  cells  of  Astasia  I  have  seldom  been  able  to  distinguish  the 
capsule  from  the  internal  contents,  on  account  of  their  smallness  and  the 
incessant  motion  of  the  animalcule.  In  Euglena,  however,  they  are  veiy 
evident ;  and  it  is  worthy  of  remark,  that  each  partakes  of  the  form  of  the 


OF  THE  PHYTOZOA.  191 

Euglena  to  which  it  belongs.  Thus,  in  E.  acus  it  is  long  and  cylindrical ;  in 
E.  viridis,  oblong  and  compressed ;  and  in  Crumenula  texta  and  Phacus,  cir- 
cular and  compressed. 

There  is  yet  another  set  of  structures  pointed  out  by  Mr.  Carter,  deve- 
loped from  the  nucleus,  to  which  he  assigns  the  nature  of  spermatozoids, 
or  male  reproductive  particles.  "  In  Astasia/'  he  writes  (p.  227),  "  irregular 
botryoidal  masses,  dividing  up  into  spherical  cells,  colourless  and  translu- 
cent, or  of  a  faint  opaque  yellow  tint,  present  themselves  so  frequently  (and 
generally  inversely  developed  with  the  o\ailes,  as  in  the  Rhizopoda),  that  I 
cannot  help  tliinking  that  they  are  also  developments  from  the  nucleus ;  but, 
from  not  having  seen  them  present  that  evident  granular  aspect  which 
characterizes  this  development  in  the  Rliizojipoda,  I  have  not  been  able  to 
determine  satisfactorily  whether  they  are  parts  of  the  latter,  or  that  kind  of 
division  of  the  sarcode  into  green  spherical  cells  which  sometimes  takes  place 
in  Efglena. 

"  In  Euglena,  also,  I  have  described  a  development  of  the  nucleus  partly 
imder  the  idea  that  it  might  be  a  parasitic  Ehizopodous  develojmient ;  but 
now  it  appears  to  me  a  simple  enlargement,  granulation,  and  segmental  de- 
velopment of  this  body  into  polymorphic,  reptant,  mucous  cells  filled  with 

spermatozoid  granules,  as  in  EMzojJods I  have  never  been  able  to  see 

the  nucleus  and  its  capsule  in  their  original  form  when  the  spermatozoid 
mass  has  been  present,  though  I  have  occasionally  in  Amoeba,  and  almost 
always  in  Euglypha,  seen  the  empty  globular  capsule  in  connexion  vrith  the 
latter." 

The  contents  of  Astasicm,  even  of  the  same  individual,  are  subject  to  great 
variations  in  colour,  distribution,  and  other  characters,  induced  by  age,  the 
action  of  the  reproductive  processes,  and  the  influence  of  external  conditions. 
Thus,  Perty  tells  us  (p.  57)  Phacus  pUuronectes  is  at  times  filled  with  a 
homogeneous  green  mass,  at  others  has  a  large,  round,  central  spot  (vacuole 
or  nucleus  ?),  at  others  a  large,  clear  space  in  the  middle,  having  a  central 
dark  nucleus ;  and  at  others,  again,  the  contained  endochrome  forms  three  or 
four  segments,  each  exhibiting  many  dark  green  nuclei.  In  Euglena  vhndis 
and  E.  Acus  the  contents  become  resolved  into  a  formless  mass,  or  into  a 
heap  of  nearly  equal-sized  germ-cells,  and  frequently  the  colour  is  changed 
from  green  to  red,  or  the  whole  organism  is  rendered  hyaline  by  the  escape 
of  the  coloiuing  matter. 

The  colom-ed  speck  in  Euglena,  AmhlyopMs,  and  other  Astasioia,  reckoned 
as  an  eye  by  Ehrenberg,  has  in  fact  no  pretensions  to  that  character.  We 
have  pointed  out  that  similar  specks  occur  in  Volvox  and  other  generally 
recognized  plants,  in  all  probabihty  precisely  similar  to  and  stnicturally  the 
same  as  those  of  Astasicm.  Sometimes  in  Euglena  the  red  is  diifased  over 
the  entire  body,  as  Cohn  represents  to  occur  in  Sj^hceroplea  annulina  {A.N.H. 
1856,  xviii.  p.  83),  in  small  globules,  which  have  the  physical  and  chemical 
relations  of  oil.  In  other  instances,  and  occasionally  in  very  young  forms, 
the  red  stigma  is  altogether  absent.  In  Phacus  pleuronectes,  Perty  states, 
one  speck  is  placed  close  behind  another  with  an  intermediate  band  uniting 
them.  Often  in  Euglence,  instead  of  one  stigma,  two  or  more  red  granules 
occiu',  whilst  in  Euglena  cleses  the  pigment-mass  is  quite  irregular.  In  Cru- 
menula  the  red  spot  is  comparatively  Yery  large,  and  rests  in  the  form  of  a 
small  obtuse  cone  upon  the  contractile  vesicle. 

''  The  eye-speck  oi  Euglena  viridis,''^  says  Perty  (p.  117),  "  is  round  or  oval, 
and  exhibits  an  elliptic  or  spherical  vesicle,  within  which  the  colouring  matter 
is  contained,  smTounded  by  a  more  or  less  comi)lete  brownish-black  ring :  at  a 
subsequent  period  the  colouring  matter  is  diffused  in  a  most  irregular  manner 


192  GENERAL  HISTORY  OF  THE  INFUSORIA. 

beyond  the  ring."  In  AmhlyopMs  viridis  the  red  jDigment  may  either  entirely 
or  only  partially  fiU  the  dark  areola.  Perty  very  sensibly  remarks,  "  All 
these  red  stigmata  are  deficient  of  all  the  requisites  of  an  eye — they  have  no 
refracting  medium  ;  and  the  presence  of  an  eye  is  inconceivable  among  beings 
which  have  neither  nervous  centres  nor  communicating  nerves.  They  are 
probably  nothing  more  than  drops  of  red-oil,  like  those  which  are  produced 
among  the  chlorophyll  in  imicellidar  Algae  "  (p.  118).  Another  fact,  bearing 
on  the  character  of  a  red  pigment- speck  in  Euglence,  is  the  change  of  colour 
these  beings  at  times  undergo  fi'om  green  to  red,  just  as  Chlamydococcus  and 
various  unicellular  Algae  do  when  they  enter  on  the  "  resting  "  stage. 

JReprodudion  of  Asfasicea. — In  Ehrenberg's  opinion,  the  members  of  this 
family  are  reproduced  both  by  self- division  and  by  ova :  he  speaks  of  having 
witnessed  the  former  process  in  the  genus  Euglena,  but  only  as  a  rare 
occurrence.  In  other  genera  he  failed  to  discover  it.  A\Tien  fission  takes 
place  it  docs  so  in  the  usual  manner,  longitudinally,  and  produces  two  equal 
and  similar  organisms ;  rarely,  the  new  beings  are  of  unequal  size.  More- 
over, in  the  encysted  condition,  which  was  mistaken  by  Ehrenberg  for  the 
death  of  the  Euglena,  or  confounded  ^Adth  other  structures,  fission  is  a  con- 
stant phenomenon. 

"WTien  the  motile  Euglena  becomes  "still,"  or  enters  into  a  state  of  rest,  it 
contracts  itself  into  a  ball,  and,  while  retaining  its  red  stigma,  loses  its  fila- 
ment. A  gelatinous  layer  is  thi'own  out  around  it,  which  gradually  hardens 
into  a  rigid  colourless  cyst :  this  at  first  lies  close  upon  the  mass  of  the  Euglena, 
but  ultimately  is  removed  from  it  all  round  by  an  interval ;  and  when  quite 
matiu'e,  it  frequently  acquii'es  a  brownish  colour  and  opacity.  In  the  encysted 
condition,  Euglena  closely  resembles  the  "stiU"  cells  of  Protococmis  ;  hence 
the  term  "  Protococcoid/'  to  express  this  condition.  When  Euglence  have 
undergone  this  transformation,  they  cohere  together  by  a  mucilaginous  ex- 
cretion, so  as  to  form  expansions  or  films  resembling  in  appearance  those 
produced  by  many  Palmellew. 

This  close  resemblance  subsisting  between  encysted  Euglence  and  the  rest- 
ing-spores  of  numerous  Algae,  e.  g.  of  (Edogonium,  explains  many  of  the 
wonderful  transformations  recounted,  such  as  the  germinating  of  encysted 
Euglena-ceWs  into  branching  filiform  Algae.  Again,  the  filmy  masses  pro- 
duced by  Euglenm  have  been  described  as  independent  genera  and  species  of 
Algae, — as,  for  instance,  those  formed  by  E.  viridis,  as  Microcystis  olivacea, 
and  those  by  E.  sanguinea,  as  Microcystis  Noltii. 

That  the  contained  green  Euglena  is  not  dead  within  its  case,  is  proved  by 
its  sometimes  being  seen  to  revolve  within  it,  and  also  by  the  circumstance 
that,  in  the  early  period  of  encysting,  on  rupturing  the  cyst,  the  contained 
being  escapes  and  resumes  the  appearance  and  movements  of  its  free  brethi^en. 
It  would  seem,  indeed,  that  Euglena:  are  in  the  habit  of  temporarily  encysting 
themselves  as  a  means  of  protection  against  injurious  external  causes,  such  as 
evaporation,  and  that,  when  a  normal  condition  is  restored,  they  throw  off 
their  protecting  envelope  and  reassume  their  active  contractile  character  and 
movements.  The  empty  cases  are  often  to  be  met  with  floating  on  the  sur- 
face of  water,  united  with  others  and  with  encysted  Euglenoi  in  a  common 
membranous  mass.  The  vitality  of  the  enclosed  being  is  further  displayed 
by  the  process  of  fission,  which  advances  in  the  power  of  two  until  very  small 
segments  are  produced,  which  soon  develope  severally  a  red  speck  and  fila- 
ment, and,  on  the  dissolution  or  rupture  of  the  common  cell-wall  of  the  parent, 
escape  as  small  free-moving  corpuscles  rather  resembhng  Monads  than  Eu- 
glence by  their  minuteness. 

The  encysting  act  maj^  transpire  in  very  small  as  well  as  in  large  Euglence, 


or  THE  PHTTOZOA.  193 

and  the  subsequent  fission  may  be  arrested  at  any  point,  so  that  either  a  few 
sections  which,  in  the  phi'aseology  of  botanists,  may  be  called  macrogonidia, 
or  other^vise  very  numerous  small  ones,  or  microgonidia,  may  be  developed. 

As  the  simply  encysted  Euglence  have  been  represented  as  independent 
genera  of  plants,  so  the  same  thing  has  occurred  when  their  contents  have 
been  seen  in  the  process  of  self- division  ;  thus,  for  instance,  Perty  thinks  it 
probable  that  Protococcits  turgidus  and  P.  clialyheus  (Kiitz)  are  no  other  than 
two  such  transitional  conditions. 

Another  circumstance  attending  encysted  Euglena',  is  the  forming  an  attach-^ 
ment  to  other  bodies  by  a  sort  of  pedicle,  which  extrudes  from  what  has  been 
the  anterior  extremity  of  the  being.  "When  viewing  large  collections  of  Eu- 
glence, specimens  may  occur  of  two  or  several  united  together  by  the  head  or 
tail,  sometimes  with  the  tail  of  one  to  the  head  of  another.  Examples  of  two 
partially  united  have  been  explained  by  supposing  the  act  of  fission  of  a 
parent-animal  to  be  nearly  accomplished ;  but  other  observers  have  seen  in 
such  united  beings  an  instance  of  conjugation,  i.  e.  of  an  act,  to  some  degree, 
of  impregnation.  The  union,  however,  of  several  by  the  tail,  sometimes  seen, 
is  an  argument  against  this  supposition,  and  is  rather  suggestive  that  such 
combinations  are  the  remnants  of  primitive  adhesions  betwei3n  gonidia  within 
the  parent-cell  or  between  germs  before  a  pellicle  has  formed  around  them, 
or,  agaiuj  that  a  mucoid  matter  thrown  out  from  the  surface,  as  happens  in 
many  Phytozoa,  may  constitute  the  band  of  union,  when  incomplete  fission  or 
persistent  primitive  adhesions  cannot  be  considered  its  origin.  There  is  cer- 
tainly no  a  priori  argument  against  the  occurrence  of  conjugation  in  this  family, 
and  some  naturalists  would,  from  analogy  with  related  beings,  look  for  it ; 
but  at  present  it  has  not,  we  think,  been  proved. 

Ovules  or  germs. — That  Euglence  reproduce  by  internal  germs  is  an  opinion 
now  advocated  by  several  naturalists.  To  oiu^  minds  this  mode  of  propagation 
is  really  homologous  with  the  formation  of  gonidia  in  admitted  plants.  Kol- 
liker  vmiea  (J.  M.  S.  i.  p.  34) — "  Multiplication  by  means  of  germs  generated 
in  the  interior  indubitably  occurs  in  certain  Infusoria  :  in  Euglena  four  to  six 
embryos  are  seen  in  one  individual,  entirely  filling  it,  which  at  length,  fur- 
nished with  their  red  speck  and  filament,  break  through  their  parent,  leaving 
it  as  an  empty  case." 

Mr.  Carter  {op.  cit.)  has  entered  very  largely  into  an  account  of  the  ovules  of 
Infusoria  and  of  their  development.  "  In  Euglena  viridis/^  he  writes,  "  the 
ovules  are  of  an  oblong  shape :  they  are  found,  like  those  oi Spongilla,  scattered 
over  the  sides  of  the  vessel,  and  evidently  have  in  Kke  manner  the  power  of 
locomotion  in  addition  to  that  of  turning  upon  their  long  axis  when  otherwise 
stationary ....  The  pellucid  central  area  in  them  corresponds  with  the  oblong 
shape  of  the  capsule  ;  but  beyond  this  and  the  central  granule  I  have  not 
been  able  to  follow  their  development  out  of  the  parent,  though,  from  the 
number  of  young  E.  virklis  present,  it  may  be  reasonably  inferred  that  they 
came  from  the  ovules.  The  young  Euglence,  however,  being  so  rapid  in  their 
movements  when  once  the  cilium  is  formed,  it  can  hardly  be  expected  that, 
except  imdcr  a  state  of  incarceration,  their  development  can  be  followed  so 
satisfactorily  as  that  of  the  slow-moving  Rhizopocl.  Instances  do  occui',  how- 
ever, where  the  ovules  gain  the  cilium  within  the  cell,  and  there  bound  about 
when  fully  developed  like  the  zoospores  of  Algae  ^^-itliin  theii'  spore- capsules. 
In  this  way  I  have  seen  them  moving  rapidly  within  the  effete  transparent 
capsuled  body  of  E.  viridis  and  in  Crumenula  texta,  where  the  spiral-fibre 
layer  is  so  strongly  developed  as  to  retain  the  form  of  the  Euglena  for  a  long 
time  after  all  the  soft  parts  have  perished.  On  these  occasions  the  embryos 
are  perfectly  colourless,  with  the  exception  of  a  central  point  which  reflects  a 


194  GENERAL  HISTOEY  OF  THE  INFrSOEIA. 

red  tint ;  and  on  one  occasion,  while  watching  a  litter  in  rapid  motion  within 
the  encysted  body  of  E.  viridis,  the  capsule  gave  way,  and  they  came  out  one 
after  another  just  as  zoospores  escape  from  the  spore-capsule  ;  but,  from  their 
incessant  and  vigorous  movement,  I  was  imable  to  follow  them  long  enough 
to  make  out  anything  more  about  them." 

This  same  observer,  moreover,  refers  to  a  rhizopodous  development  of  the 
nucleus  of  Euglena,  whereby  the  form  of  an  "  actinophorous  Rluzopocl "  is 
assumed,  from  which,  in  his  opinion,  young  Euglence  are  probably  developed. 

Perty,  again,  records  some  original  observations  on  the  development  of 
Euglence  from  ovules  or,  as  he  terms  them,  germs  (Keime).  At  p.  79  he 
states  that,  among  numerous  veiy  minute  resting  germs,  intermingled  with 
larger  indi\-iduals,  some  were  seen  to  acquire  the  faculty  of  motion,  to  stretch 
themselves  out,  and  to  assume  the  form  of  Cereomonas.  Between  such  and 
completely-formed  Euglence  every  intermediate  size  occurred.  The  motionless 
spheroidal  germs  set  free  by  the  dissolution  of  the  parent-cell  soon  develope 
a  tapering  extremity,  terminated  by  a  locomotive  filament,  at  the  base  of 
which  is  a  hyaline  space,  and  in  and  near  to  this  a  dark  speck  which  subse- 
quently changes  to  red.  The  differentiation  of  the  homogeneous  contents  of 
the  granules,  out  of  which  the  germs  are  to  be  developed,  takes  place  at  a  very 
early  period,  but  not  in  the  same  way  or  time  in  all  specimens ;  neither  do 
aU.  the  young  of  a  brood  attain  the  same  dimensions  and  figure  ;  indeed  but 
few  attain  a  considerable  size,  and  many  acquire  an  abnormal  figiu^e.  For 
example,  Perty  regards  AmhJgoplils  viridis  as  only  an  accidental  variety  of 
Euglena,  of  large  size  and  trimcate  at  one  end ;  for  he  has  remarked  nimierous 
small  indi\iduals,  derived  from  a  Euglence,  also  with  a  truncated  extremity. 
Further,  he  reports  the  multiplied  varieties  in  form,  in  colour,  and  in  arrange- 
ment of  contents,  &c.,  which  occur  in  collections  of  the  same  species  of 
Euglena,  and  adds  that  the  great  differences  exhibited  by  E.  viridis,  when  in  a 
dying  condition,  are  most  varied  and  inexjilicable.  In  illustration  of  this 
opinion,  he  remarks  that  the  utmost  variety  of  fonn  oeciu's ;  or  all  the  vesicles 
and  granules  change  to  a  red  colour  or  become  transparent ;  or  the  vesicles 
vanish  and  the  green  mass  contracts  itself  into  a  small  ball,  or  otherwise  dis- 
appears, leaving  only  an  empty  shell.  In  the  last-named  state  the  stigma 
often  retains  a  black  coloiu\  The  empty  envelopes  frequently  accumulate  so 
as  to  form  masses  resembling  a  vegetable  cellular  tissue,  and  in  one  instance 
approached,  bj^  mutual  pressiu^e,  a  regular  hexagonal  figure.  Some  such  acci- 
dental groupings  of  \\dthered  Euglena-eells  have  been,  as  Perty  believes, 
described  under  the  name  of  Pcdmella  botri/oides  by  Kiitzing  ;  and  Cereomonas 
vhmlis,  and  also  probably  Bodo  viridis,  are  merely  phases  of  development  of 
Euglena  viridis. 

There  is  a  distinct  concordance  between  Carter's  and  Forty's  account  of 
the  development  of  the  contents  of  Euglena'  into  minute  germinal  bodies,  or, 
as  we  may  legitimately  call  them,  microgonidia ;  and,  on  the  other  hand,  the 
formation  of  two-  and  four-fission  products  (in  other  words,  the  formation 
of  macrogonidia  from  these  beings  in  their  still-condition)  has  been  a  matter 
of  direct  observation.  Consequently  the  developmental  history  of  Euglena  is 
so  far  complete ;  and  it  only  remains  for  naturalists  to  witness  the  actual 
relation,  the  contact  and  incorporation  of  the  micro-  with  the  macrogonidia, 
to  bring  this  genus  within  the  same  pale  as  Volvox,  in  reference  to  its 
sexuality. 

Mr.  Carter  has  reverted  to  his  notes  on  the  ovules  or  germs  of  Euglena,  in 
his  just-published  paper  on  Eudorina  {A.  N.  H.  1858,  ii.  p.  245),  in  the 
following  remarks  : — "  There  is  no  doubt  that  E.  viridis  becomes  chstended 
with  the  cells  which  T  have  heretofore  described,  and  thouo'ht  to  be  ovules 


OF  THE  PHTTOZOA.  195 

or  embryonic  cells,  and  that  during  this  time  the  chlorophyll  passes  into  red 
grains,  and  subsequently  disappears,  while  the  organism  is  secreting  a  capsule 
around  itself,  and  its  original  cell-wall  passes  into  a  tough  spherical  ovisac,  so 
to  speak.  But  what  becomes  of  this,  if  it  be  the  result  of  impregnation,  or 
what  the  process  of  impregnation  is  like,  or  when  it  takes  place,  is  for  future 
discovery  to  determine." 

ChJoroc/onium  eiichlorum  (PI.  XX.  15-21)  was  the  subject  of  an  interest- 
ing observation  by  Weisse  (Wiegmann's  Archiv,  1848),  who  thought  he  had 
demonstrated  in  this  species  propagation  by  ova  or  germs,  and,  in  fact,  elu- 
cidated in  it  the  development  of  microgonidia,  by  repeated  acts  of  self-fission 
of  the  contents,  just  as  in  the  spores  of  Algae.  For  instance,  he  described  the 
contained  green  matter  of  the  fusiform  being  fii'st  to  contract  in  some  mea- 
sure upon  itself  (XX.  16),  then  to  exhibit  a  constriction  followed  by  a  line 
of  division  into  two  portions,  which,  by  subsequent  redivisions,  resolved  the 
whole  into  a  nodular  mass  resembKng  a  bunch  of  grapes  (XX.  17-18). 
This  grapebunch-like  mass  possessed  a  certain  mobility  within  the  enclosing 
integument;  and  as  the  process  of  development  proceeded  further,  its  se- 
veral particles  or  segments  displayed  a  movement  among  themselves,  which  in- 
creased in  extent  and  vigour  until  the  external  envelope  gave  way  before  it, 
and  permitted  their  escape  in  the  form  of  so  many  distinct  particles  or  beings 
(gonidia)  endowed  with  ciliary  filaments,  whereby  they  kept  up  an  active 
movement  in  the  surroimding  water  (XX.  21).  The  young  forms  produced 
exhibited  active  movements  within  the  parent- cell,  and  at  one  stage  prior  to 
theii'  discharge,  when  connected  together  in  heaps,  resembled  Uvella  Bodo. 
On  the  ruptui^e  of  the  cyst  they  escaped  freely  into  the  water  with  the  fig-ure 
of  Chlorogoniwn. 

Schneider  has  also  some  remarks  on  this  genus  {A.  N,  H.  xiv.  p.  326). 
He  could  discover  no  decided  red  speck,  although  as  many  as  twelve  reddish 
spots  were  distributed  over  the  surface  of  the  green  mass ;  a  contractile  vesi- 
cle, moreover,  eluded  his  search.  Of  the  mode  of  propagation  he  reports  that 
''  division  takes  place  in  the  interior  of  the  investing  membrane,  in  exactly 
the  same  manner  as  in  Polytoma.  The  number  of  individuals  produced  is 
never  less  than  four,  but  often  as  many  as  thirty- two ;  in  the  latter  case  they 
are  very  small,  but  always  resemble  the  parent  in  other  respects.  A  spheri- 
cal state  of  rest  also  occui'S.  It  appears  that,  when  the  requisite  conditions 
are  present,  the  young  proceeding  from  the  division  of  the  parent  pass  into 
this  state  immediately  after  they  are  set  free, — their  soft  investing  mem- 
brane probably  rendering  them  fitter  for  this  purpose.  The  contractions 
which  then  take  place  are  probably  the  same  that  were  observed  by  Ehi^en- 
berg.  In  other  respects  I  have  found  the  form  unchangeable ;  and  Clilo- 
rogonium  must  consequently  be  separated  from  the  Astasicm,  amongst  which 
it  has  hitherto  been  arranged.  On  the  addition  of  iodine,  only  a  few  blue 
granules  are  to  be  seen  in  the  fusiform  individuals ;  the  green  spheres,  on  the 
contrary,  which  are  completely  filled  with  green  granules,  acquire  a  deej^  blue 
colour  with  this  reagent :  if  the  colouiing-matter  be  destroyed  by  means  of 
concentrated  sulphimc  acid,  the  granuifes  are  dissolved,  and  on  the  addition  of 
iodine,  a  beautiful  blue  colour  is  produced.  By  long  keeping,  the  green  of  the 
cyst  passes  to  red.  The  cysts  are  not  to  be  roused  from  their  toi^oid  condi- 
tion by  the  production  of  fermentation.  I  have,  however,  observed  their  re- 
vivification under  other  circumstances ;  but  my  materials  are  insufficient  to 
enable  me  to  describe  the  mode  of  reproduction  of  the  investing  membrane 
and  filaments,  which  would  certainly  be  interesting.  The  conditions  required 
for  the  existence  of  Chlorogonium  are  apparently  quite  different  from  those  of 
Polytoma  :  the  former  did  not  multiply  abundantly  in  infusions  imtil  the 


fa 


196  GENERAL  HISTOEY  OF  THE  INFrSORIA. 

latter  had  passed  to  the  state  of  repose."  This  view  of  the  affinity  of  Chlo- 
rogonium  accords  with  that  which  Weisse  indicates  in  the  statement  that  this 
genus  and  Glenomorur,i  tingens  (species  of  Ehrenberg's  family  Monadind)  are 
but  two  phases  of  the  same  being. 

Weisse  has  appended  some  remarks  to  the  preceding  account  by  Schneider 
Midi.  Archil',  1856,  p.  160).  He  says  that  he  mtnessed  the  revivification 
of  encysted  Cldorogonia  (a  phaenomenon  unnoticed  by  Schneider)  on  placing 
some  cysts,  collected  the  preceding  year,  in  water.  The  reddish  and  pre- 
viously spherical  cysts  were  seen  to  gradually  lose  their  regular  outhne  by 
the  elongation  of  one  end,  and  thereby  to  acquire  an  ovate  form.  After  a 
short  time  the  naiTower  end  of  the  cyst  ruptured,  and  a  very  thin-walled 
vesicle  protruded  through  the  rent :  whilst  this  took  place,  a  movement  of 
the  contents  of  the  cyst  became  evident ;  and  after  a  while  several  constric- 
tions appeared,  which  extended  deeper  until  they  di\ided  the  whole  into  four 
portions.  For  a  time  the  protniding  sac  elongated  itself  more  and  more,  but 
ultimately,  owing  to  the  pressure  within  it  of  the  moving  particles,  gave  way 
and  allowed  their  exit.  The  escaped  sections  were,  as  a  rule,  of  pretty  uniform 
sizes,  but  had  not  the  remotest  resemblance  to  the  mature  Chlorogonium,  and 
indeed  might  have  readily  been  assigned  to  another  group  of  beings.  Their 
figure  was  elongated,  irregular,  and  often  triangular,  on  fii^st  escaping  from 
the  cyst ;  they  were  also  flexible  in  every  direction,  and  of  a  dusky  brown 
colour.  After  dispersion,  on  reaching  the  margin  of  the  drop  of  water,  they  re- 
sumed a  globular  shape,  changed  to  a  rusty  red  colour,  and  after  a  few  hoiu's 
assumed  the  appearance  of  clear-green  spindle  or  bodo-shapcd  organisms. 
Between  their  evolution  from  the  cysts  and  their  development  into  the  form 
of  ChJor^ogonium,  two  hours,  less  or  more,  intervened.  This  di^^sion  into  four 
segments,  representing  four  new  beings  of  Chlorogonium  progressively  evolved, 
apparently  without  actual  metamorphosis,  may  be  rightly  esteemed  an  act  of 
reproduction  by  macrogonidia,  whilst  the  breaking  up  of  the  organism  into  a 
multitude  of  zoospores,  as  previously  described  by  Weisse,  is  a  process  of  re- 
production by  microgonidia. 

Kature  of  Astasi^a. — It  is  with  certain  members  of  this  family  that 
Thuret  pointed  out  (Ann.  iSc.  Nat.  1850,  xiv.)  the  close  resemblance  to  the 
zoospores  of  Algae,  amoiinting,  as  far  as  outward  appearances  indicate,  to 
actual  identity. 

"This  affinity,"  he  says,  ''is  exhibited  in  the  colour,  form,  in  the  number  and 
character  of  the  ciliary  filaments,  in  the  contents,  not  excepting  the  coloui-ed 
eye-speck,  in  the  mode  of  self-fission,  and  also  in  the  power  of  locomotion. 
What  is  still  more,  both  zoospores  and  Astasicca  tend  to  the  light,  disengage 
a  gas,  most  probably  oxygen,  and  emit  a  peculiar  spermatic  odour.  However, 
by  continued  watching  the  zoospores  are  seen  to  affix  themselves  to  some  body, 
surrender  their  seeming  animal  life,  and  proceed  to  germinate,  developing  a 
tissue  similar  to  that  of  the  plant  which  gave  them  birth.  On  the  other  hand, 
the  true  Astasicva,  if  they  attach  themselves,  it  is  but  for  a  time,  and  no  ap- 
pearance of  germination  ensues.  The  closest  similarity  exists  in  the  case  of 
the  Chlamydomonas pidvisculus  (Diselmis  viridis,  Duj.),  and  in  a  less  degree 
in  the  Euglence, ....  In  the  form  of  the  body,  in  that  of  the  flabelliform  ciha, 
and  in  the  disposition  of  those  cilia,  as  also  in  the  contents  of  the  body, 
the  resemblance  is  complete.  The  movements  of  Diselmis  are  like  those  of 
zoospores  ;  and,  like  them,  they  tend  to  the  Hght.  In  one  distinct  species,  or 
rather,  in  a  particular  state  of  the  same  species,  a  very  clear  red  spot  is  dis- 
cernible, and  a  central  globule,  very  hke  in  appearance  to  the  amylaceous 
granules  so  frequent  in  the  cells  of  green  Algae.  These  Infusoria  appear  to 
act  on  the  atmospheric  air  like  Algae  and  the  green  parts  of  other  plants,  dis- 


OF  THE    PHYTOZOA.  197 

engaging  a  gas  (oxygen  ?)  under  the  influence  of  light.  They  exhale  an  evi- 
dent spermatic  odour.  Their  reproduction  occurs  by  spontaneous  division, 
2-4  young  ones  being  formed  within  the  common  integument.  I  have  ob- 
served the  same  mode  of  reproduction  in  the  Euglem^,  which  act  on  the  air 
and  tui^n  to  the  light  like  DiseJmis,  but  have  an  extremely  contractile  body 
changing  its  figure  every  moment,  which  will  not  admit  of  their  being  con- 
founded with  zoospores,  and  leaves  no  doubt  of  their  animality.  This  binary 
or  quaternary  division  is  met  with  also  in  the  various  species  of  TetmsporcBy 
which,  though  arranged  mth  the  Algae,  appear  to  me  of  very  doubtful  vege- 
table nature.  In  Tdraspora  gelatinosa  I  have  recognized  green  globules,  dis- 
posed in  foiu's,  and  each  furnished  with  two  cilia  of  extreme  length,  which 
are  lost  in  the  gelatinous  mucus  of  which  the  frond  of  this  supposed  plant  is 
constituted.  All  these  productions,  as  well  as  Gonium,  Pandorina,  Volvo.v, 
Protococcus  nivalis,  &c.,  present,  in  my  opinion,  characters  of  animality 
too  decided  and  too  permanent  for  it  to  be  possible  to  refer  them  to  the 
vegetable  kingdom  ;  and  I  think  it  would  prove  more  convenient  to 
unite  them,  with  aU  the  other  Infusoria  (Poh/gastrica)  coloured  green,  in 
one  and  the  same  group,  which  might  be  called  CJilorozoidece.  We  have 
before  noticed  the  sweeping  statement  of  M.  Agassiz,  that  all  the  mouth- 
less  Infusoria  are  nothing  but  various  forms  and  phases  of  development  of 
Algte." 

Although  many  natm-alists  stoutly  claim  the  Astasicea,  and  the  genus  Eu- 
glena  especially,  as  plants,  yet  others,  and  among  them  some  of  the  most 
able,  particularly  in  Germany,  stiLL  pronounce  them  animals.  But,  as  we 
have  before  noticed,  there  are  undoubted  Euglena-iorms  which  are  actually 
phases  of  existence  of  known  plants,  and  which,  if  watched,  may  be  followed 
in  their  development  until  by  germination  they  assume  all  the  special  fea- 
tures of  those  plants  ;  and,  on  the  other  hand,  there  are  EuglencB  which  at  no 
period  of  their  existence  can  be  seen  to  germinate,  although  they  may  exhibit 
a  plant-like  condition  when  encysted  and  motionless,  like  Protococcus  resting- 
cells. 

As  an  example  of  the  former  set  of  transitional  beings,  we  may  aj)peal  to 
the  observations  of  Itzigsohn  already  recorded  (p.  125),  showing  that,  in  the 
development  of  Oscillatorice,  minute  Chlamydomonads  are  transformed  into 
Eagleme,  that  these  in  their  turn  generate  microgonidia,  which,  after  some  in- 
termediate transformations,  eventually  produce  the  '  Leptothrix,''  and  lastly 
the  perfect  OsciUatoria.  Another  illustration  might  be  adduced  from  Cohn's 
essay  on  Protococcus  pluvialis,  in  which  he  points  out  both  an  Astasia-  and  a 
Euglena-\SkQ  phase  of  that  unicellular  plant.  Let  it,  however,  be  noted  that 
whilst  Cohn  records  a  Ejiglena-yihdL^e  in  Protococcus,  he  nevertheless  admits 
the  existence  of  animal  Euglence,  distinguished  by  their  extraordinary  con- 
tractihty  (Entiu.  p.  208).  Withal,  this  distinguished  observer's  discovery  of 
the  mutual  sexual  relation  of  micro-  and  of  macrogonidia  constitutes  (sup- 
posing these  reproductive  products,  as  seems  to  be  actually  the  case,  to  be 
generated  in  EiiglencB)  an  additional  argument  for  theii'  vegetable  natui^e,  by 
bringing  them  Tvithin  the  same  category  of  organized  beings  as  Volvox  and 
PaiKlorina. 

If  Mr.  Carter  be  correct  in  his  account  of  Astasia,  this  genus  can  no  longer 
remain  in  the  category  of  doubtful  organisms,  but  must  forthwith  be  trans- 
ferred to  the  animal  kingdom  ;'  for  he  asserts  the  existence  of  a  mouth  with 
a  complicated  buccal  apparatus  for  biting  off  and  taking  in  food,  of  a  strong 
prehensile  organ,  and  stomach-sacs.  Besides,  he  speaks  of  its  near  affinity 
mth  Amoeba,  and  refers  it  to  the  Rhizopoda.  In  Euglena,  on  the  contrary,  no 
mouth-  or  stomach-vesicles  are  discoverable,  and  the  filament  is  comparatively 


li 


198  GENEKAL  HISTORY  OF  THE  INFUSOEIA. 

imperfectly  developed ;  hence  Mr.  Carter  allies  this  genus  rather  with  the 
zoospores  or  gonidia  of  Algae,  and  assumes  that  it  must,  like  other  mouthless 
organisms,  derive  its  nutrition  through  endosmosis.  Cohn,  on  the  other 
hand,  although  cognizant  of  many  plant-like  features  in  Euglena,  cannot  ac- 
quiesce in  detaching  it  from  animalcules,  because  of  its  great  contractihty 
and  of  the  fact  that  there  are  undoubted  animals,  such  as  Opalina,  Rhizojwda, 
Gregarina,  Trematoda,  &c.,  which  want  the  special  animal  characteristic  of  a 
mouth. 

Mr.  Carter  would,  it  seems,  recognize  both  Euglena  and  Astasia  as  close  alhcs 
with  Amoeba, — an  affinity  remarked  by  Ehrenberg,  who  placed  the  family  As- 
tasioia  between  Chsterina  and  Amoeba^a,  treating  the  variability  of  the  form  of 
the  body  as  a  leachng  characteristic.  Indeed,  the  first-named  observer  alludes  to 
an  actual  transition  of  Astasice  into  Amcebce,  in  the  following  paragraph  {A. 
N.  H.  xvii.  1856,  p.  115): — ''  Young  Astasice  are  developed  within  the  cells 
of  Spirogyra  to  a  great  extent ;  and  although  they  at  first  have  almost  as 
much  polymorphism  as  an  Amoeba,  still  they  retain  their  cilium,  and  after  a 
while  assimie  the  form  and  movements  pecuhar  to  Astasia.  I  might  here 
mention  that  on  one  occasion  I  saw"  a  lay^ge  Amoeba  with  a  long  cilium  at  one 
time  assuming  the  foim  of  Astasia,  and  at  another  that  of  Amoeba,  which  thus 
gives  us  the  link  between  these  two  Infusoria.  The  cilium,  however,  had  not 
the  power  of  the  filament  of  Astasia,  though  it  occasionally  became  terminal." 
At  a  previous  page,  a  rhizopodous  development  of  the  contents  of  Euglena; 
into  granuliferous  Amoeba;  of  a  pinkish  colour  has  been  adduced  as  a  fact 
noticed  by  the  same  observer. 

We  need  not  stay  to  examine  the  vital  endowments  and  habitats  of  the 
Astasice  ;  for,  except  the  facts  occuiTing  in  the  preceding  history  of  the  family, 
and  in  the  general  account  of  Phytozoa,  there  is  nothing  important  to  adduce. 


OF  THE  PROTOZOA.  199 


Sect.  III.— OF  THE  PROTOZOA. 
(Plates  XXI.-XXXI.) 

The  term  Protozoa,  borrowed  from  two  Greek  words,  protos,  first  or  primi- 
tive, and  zoon,  an  animal,  has  of  late  been  very  generally  adopted  to  signify 
the  simplest  forms  of  animal  life.  Upon  a  review  of  these  rudimentary 
animals,  it  is  at  once  perceived  that  they  differ  among  themselves  in  organiza- 
tion— that  whilst  some  are  amorphous  and  almost  homogeneous,  others  exhibit 
a  degree  of  differentiation  of  parts,  and  the  fii'st  vestiges  of  internal  organs  to 
carry  on  the  processes  of  hfe ;  again,  it  is  seen  that  some  have  a  distinct  orifice 
for  the  admission  of  food,  or  a  mouth,  which  in  others  is  absent,  and,  lastly, 
that  some  with  a  definite  figm^e  are  moved  by  vibratile  cilia,  whilst  others 
slowly  progress  by  the  alternate  protrusion  and  retraction  of  ever- changing 
and  changeable  processes  derived  from  the  general  mass  of  their  body. 

From  a  consideration  of  these  structiural  differences,  one  division  of  the 
Protozoa  is  suggested  into  those  moved  by  cilia,  and  those  moved  by  variable 
processes  or  ^  pseudopodes  ' ;  and  a  second,  into  those  furnished  with  a  mouth, 
and  those  which  are  mouthless.  We  have  accordingly  constituted  two  pri- 
mary divisions,  viz.,  1.  Ciliata,  Protozoa  moved  by  cilia  ;  and  2.  KJiizopoda, 
moved  by  variable  processes.  The  Rliizopoda  (XXI.)  are  all  mouthless,  or 
^  astomatous,'  whilst  the  Ciliata  (XXIV.-XXX.)  have  a  mouth,  and  are 
styled  by  Siebold  '  Stojnatoda,^  with  the  exception  of  a  small  family,  the 
Opalincea  (XXII.  46,  47),  and  perhaps  also  of  that  of  the  Peridinicea 
(XXXI.  16-23). 

However,  besides  the  beings  usually  included  among  the  Ciliata  andi^A/zo- 
poda,  there  are  several  subordinate  Protozoic  groups,  some  of  which  either 
stand  as  it  were  midway  between  them,  or  represent  a  development  of  the 
amoi-phous  and  mouthless  Rhizopoda  in  a  different  direction ;  such  are  the 
Gregarinida  (XXII.  28-36),  with  the  associated  Psorospermia  (XXII.  37- 
41),  the  Spongiada,  Thalassicollida,  and  Polycystina,  all  which  must  rightly 
also  be  numbered  with  the  Protozoa. 

Of  the  Ciliata  themselves,  there  is  a  fiu-ther  and  higher  development  of 
their  type  in  the  subordinate  groups  of  Ichthydina  (XXII.  46-47)  and  Noc- 
tilucida  (XXXL),  and,  on  the  other  hand,  a  degradation  of  it,  as  ah-eady 
noted,  in  the  case  of  the  Opalincea  and  Peridinicea.  Here  we  would  remark 
that  the  term  '  Infusoria '  has  been  employed  by  several  writers,  in  hen  of 
that  of  Ciliata,  which  we  adopt ;  still  it  is,  to  oui'  mind,  both  less  appropriate, 
and  also  open  to  objection,  not  only  on  account  of  its  meaning  being  quite 
indefinite,  but  also  by  its  having  everywhere  acquii'ed  a  very  much  wider 
signification,  in  consequence  of  which  it  will  always  be  open  to  misconception 
when  apphed  to  a  comparatively  very  small  class  instead  of,  as  heretofore,  to 
a  very  various  and  ^vide  collection  of  microscopic  organisms.  Another  word 
invented  is  '  Stomatoda,'  which  is  precisely  equivalent  in  the  extent  of  its 
signification  with  the  term  Ciliata,  the  mouthless  families  only  being  excluded. 

Excepting  their  subordinate  groups,  the  organisms  comprehended  among 
the  Ciliata  and  Rhizopoda  formed,  in  conjunction  with  the  Desmidiece,  Dia- 
tomece,  and  the  families  we  have  brought  together  imder  the  appellation 
Phytozoa,  the  great  class  Polygastrica  in  the  system  of  Ehrenberg.  Little 
reflection  is  necessary  to  convince  ourselves  of  the  very  heterogeneous  nature 


200  GEA'EEAL  HISTORY  OF  THE  INFUSORIA. 

of  the  collection  of  li^-ing  objects  assembled  in  that  class ;  and  even  Ehrenberg 
himself  would  never  have  suggested  such  a  grouping,  had  he  not  imbibed  the 
hypothesis  of  a  pervading  uniformity  of  organization  possessed  by  the  simplest 
animated  beings  in  common  mth  animals  considerably  advanced  in  the  scale, 
and  under  its  influence,  aided  by  his  imagination,  found  in  all  these  various 
organisms,  a  polygastric  structure,  viz.  an  apparatus  of  numerous  stomach- 
sacs,  communicating  dii^ectly  or  indirectly  with  the  mouth.  Notwithstanding 
the  many  prominent  errors  in  Ehrenberg's  classification,  he  rightly  recognized 
in  framing  it  the  value  of  the  external  means  of  locomotion,  and  distinguished 
a  group  of  PoJygastrica  under  the  name  of  Pseudopoda. 

Siebold,  who  proposed  the  term  Protozoa,  limited  it  to  two  classes,  distin- 
guished as  the  '  Infusoria  '  and  the  '  Rhizopoda  ',  omitting  the  supplementary 
groups  above  mentioned.  The  Infusoria  he  di\ided  into  two  orders,  the 
*  Astoma '  and  '  Stomatoda,'  the  latter  of  which,  together  with  two  of  the 
three  families  of  Astoma,  is  e(]uivalent  to  our  class  Ciliata,  its  remaining 
family  Astasuea  being  a  member  of  oiu'  group  of  Phytozoa. 

The  Protozoa,  as  understood  by  us,  may  be  thus  exhibited  at  one  view. 

Ciliata.  Eiiizopoda. 

f.   .  r  Opalingea  a.  Amoebsea 

a.      s  oma      |  Peridinigea  (?)  b.  Monothalamia  or  Monosomatia 


b.  Stomatoda 


c.  Polythalamia,  Polysomatia,   or 
Foraminiiera. 


Gregarinida 
Psorospermia 

N^JUill Suppleruentar,  groups. 


'  Polycystina 
ThalassicoUida 
Spongiada 


In  treating  of  these  several  classes  and  groups  we  shall  commence  with 
the  Phkopoda,  omitting,  however,  lest  our  subject-matter  be  too  much  ex- 
tended, the  Polycystina,  ThalassicoUida,  and  Sjjongiada  ;  we  shall  next  pro- 
ceed with  a  brief  description  of  the  Greyarinida,  and  its  subordinate  family 
Psorospermia,  and  then  after  considering  the  Opalinoea  and  Peridinicea  as 
intermediate  groups,  proceed  to  detail  the  history  of  the  perfect  Ciliata — 
the  Stomatoda, — finishing  our  account  Avith  the  Ichthydina  and  Noctilucida 
as  the  highest  developments  of  Protozoic  life. 

As  a  result  of  our  inquiry,  we  shall  see,  on  the  one  hand,  in  the  true 
Ciliata,  sim^^le  animal  organized  matter,  with  a  very  sKght  amount  of  differ- 
entiation, attain  its  acme  of  development  in  the  Vorticellina,  and  in  these 
animalcules  exhibit  a  superiority  in  organization  above  the  lowest  links  of 
groups  relatively  higher  in  the  chain  of  animal  life  ;  and,  on  the  other  hand, 
in  the  Rhizopoda,  of  still  simpler  organization,  the  same  organic  living 
material  developed  in  a  totally  different  dii'ection  to  a  maximum  in  the  most 
beautiful  and  complex- shelled  Foraminifera,  which  in  outward  form,  although 
in  no  real  homology,  emulate  the  highest  class  of  Invertebrata,  viz.  the 
Cephalopoda 

Another  lesson  may  also  be  derived  from  the  objects  of  our  present  study, 
viz.  the  fact  of  the  marvellous  variations  which  can  be  made  out  of  one  or,  it 
may  be,  two  elementary  stnictm^es.  Thus  the  simple  contractile  substance  which 
can  live  independently  in  the  Amoeba  condition  (XXI.  1-4 ;  XXII.  1-23) 
encases  itself  in  a  one-chambered  shell  in  the  Monothalamia  (XXI.  6-19), 
and  into  a  many- chambered  one  in  the  Polythalamia  (XXI.  20-36),  and  again 
lives  partly  within  and  partly  without  the  curious  silicious  skeleton  of  Poly- 


OF  THE  PROTOZOA. EHIZOPODA.  201 

cysthia,  and  in  singular  relation  with  a  spiciila  skeleton  in  Sjpongiada  and 
TJialasskoUlda. 

So,  if  we  look  to  the  Ciliata,  we  find  that  the  hardening  of  the  superficial 
lamina  of  their  substance  into  a  sort  of  integament  gives  rise  to  numerous 
modifications  in  external  form  and  fimctions,  according  to  the  degree  of 
induration,  and  the  processes  sent  out.  The  flexible-skinned  Colpodea 
(XXIX.  25-50)  depend  for  their  movements  upon  their  garnitiu-e  of  \-ibratile 
cilia,  and  are  merely  swimmers,  whilst  the  hard-coated  Euplota  (XXV.  350- 
353)  produce  short  moveable  processes  which  act  as  legs,  upon  which  they 
can  rapidly  creep.  Lastly,  the  selfsame  primitive  contractile  substance  is 
formed  into  a  stem  in  the  Vorticella,  which  supports  the  animalcule  at  its 
apex,  and  exhibits  helicoid  contractions,  astonishing  both  by  their  rapidity 
and  completeness. 

SUBSECTION  I.— EHIZOPODA. 
(Plates  XXI.  XXII.) 

The  true  Wiizopoda  constitute  a  large  class  of  microscopic  animated  beings 
of  the  most  simple  character.  They  may  be  defined  as  non-ciliated  Protozoa 
moving  by  variable  expansions.  Their  organic  animal  substance  presents  no 
distinction  of  tissues  or  of  organs,  but  is  homogeneous,  contractile,  and  trans- 
lucent, resembling  a  tenacious  mucus  or  soft  tremulous  jelly,  and  is  perpetually 
changing  its  form  by  expanding  itself  at  one  or  several  points  into  processes 
of  ever-vaiying  dimensions,  arrangement,  and  number,  and  called  in  conse- 
quence ""  variable  processes."  Inasmuch,  moreover,  as  these  shifting  offshoots 
are  their  only  means  of  locomotion,  they  have  frequently  been  called  "  feet," 
and,  as  they  are  also  characteristic  of  the  class,  have  given  origin  to  the  terms 
*^  Pseudopoda  "  (with  false  feet)  and  "  EMzopoda  "  (root-like  feet)  to  desig- 
nate it.  Again,  the  lining  mass  is,  in  numerous  instances,  capable  of  enclos- 
ing itself  by  a  sheU  of  various  figaire,  consistence,  and  complexity ;  and  such 
variations  serve  to  separate  the  Ehizopoda  into  famihes  and  genera. 

In  the  simplest  shell-less  beings  (XXI.  3,  4),  vitality  is  exhibited  by  the 
slow  protnLsion  and  retraction  of  the  variable  processes,  by  the  change  of 
form,  their  onward  movement,  and  the  introduction  of  nutritive  substances, 
and  by  the  gradual  changes  of  the  introduced  matters  indicating  a  digestive 
act.  They  therefore  manifest  vital  contractility,  a  power  of  locomotion,  a 
degree  of  sensibility,  and  a  digestive  process. 

Eepeated  observation  likewise  reveals  the  fact  of  progressive  growth,  and 
the  faculty  of  reproduction.  The  testaceous  forms  exhibit  their  \itality 
after  the  same  manner,  and  surpass  the  naked  Ehizopoda  only  in  the  mar- 
vellous power  of  secretion  displayed  in  the  production  of  their  shells  (XXI. 
6-3G). 

Although  in  organization  the  Ehizopoda  stand  even  below  the  ciliated 
Protozoa,  yet  an  animal  natui'e  must  be  allowed  them ;  indeed  the  simplest 
forms  are  the  rudest  specimens  of  animal  existence.  Under  the  term  RJiizo- 
ptoda  are  comprised  three  well-marked  families,  viz.  the  Amcehina  or  Amoehcea, 
which  are  without,  and  the  Monothalamia  and  the  Foraminifera,  with  shells. 
The  Monothalamia  have  one  large  opening  to  their  monolocular  (one-celled) 
shells  (XXI.  6-17) — hence  the  name, — whilst  the  Forambiifera  owe  theii^  de- 
signation to  the  existence  of  numberless  small  orifices,  generally  distributed 
over  a  multilocular  (many-celled  or  chambered)  testa  (XXI.  20-36). 

We  have  frequently^  in  the  following  pages,  used  the  term  ArceUina  as 
sjTionymous  with  Monothalamia  ;  for  although  the  family  known  to  Ehrenberg 
under  that  name  comprehended  only  a  portion  of  the  genera   that  Schultze 


202  GENERAL  HISTOKY  OF  THE  INFUSOKIA. 

arranges  in  his  group  of  single -chambered  or  nionolocular  shells,  yet  its 
meaning  may  be  equally  extended. 

It  would  probably  have  been  correct  to  have  placed  the  Acmetina  (XXIII.) 
among  the  Rhizopoda,  as  another  family  closely  allied  to  the  Amoehina  ;  but 
the  detail  of  their  peculiarities  would  have  too  much  embarrassed  the  general 
description  of  structure  which  we  have  endeavoiu'ed  to  give  of  all  the  usually 
acknowledged  or  true  Rhizopoda  ;  we  have  therefore  preferred  to  describe 
them  as  a  subclass  in  the  follo^ving  chapter. 

The  examination  of  the  Ehizopoda  requires  to  be  conducted  with  great  care 
and  skill, — a  requirement  sufficiently  illustrated  by  reference  to  the  erroneous 
notions  and  descriptions  of  the  older  observers.  They  must  be  viewed  in  aU 
positions  under  different  degrees  and  modes  of  illumination,  by  reflected  as 
well  as  by  transmitted  light,  and,  especially  in  the  ease  of  the  testaceous 
varieties,  after  submitting  them  to  pressiu^e  and  to  the  action  of  various 
chemical  agents,  or,  when  sufficiently  large,  after  making  sections  of  them  in 
different  dii^ections. 

The  organic  Kving  mass  of  all  Ehizopoda  is  alike,  and  corresponds  with  the 
"  Sarcode  "  of  ciliated  Protozoa  and  with  the  amorphous  contractile  substance 
of  Hydra  and  of  other  low  organisms.  It  appears  in  the  present  class  a  con- 
tractile, highly  elastic,  colomiess,  almost  fluid  mucus,  hyaline  or  diaphanous, 
homogeneous,  and  in  refracting  power  cliffeiing  little  from  water.  Xo  di- 
stiQction  into  an  enclosing  fii-mer  membrane  or  integument  and  contents  is 
discoverable ;  and  cilia  are  never  found.  These  characters  exist  in  entirety 
only  in  very  yoimg  animals ;  for  at  a  veiy  early  period  molecules,  granules, 
and  globules  or  vesicles,  and  various  foreign  particles,  make  theii^  appear- 
ance, diminish  the  transparency,  and  often  impart  colour. 

A  new  species  of  Amceba,  figiu'ed  by  Schultze,  the  A.  ghhularis,  is  repre- 
sented as  ha\ing  a  thin,  transparent,  colourless  lamina  of  contractile  substance, 
from  which  the  processes  are  given  off,  and  which  surrounds  a  globular,  co- 
loured, and  granular  chief  or  nuclear  mass  (XXI.  1,2).  A  similar  distribution 
of  the  substance  of  an  Amceha  into  a  hyaline  colourless  cortical,  and  a  granu- 
lar coloiu'ed  medullary  portion,  is  represented  by  the  same  author  in  another 
species ;  and  it  is  moreover  a  structiu^e  homologous  vdth  that  in  the  allied 
genus  Actinoijlirys  (XXIII.  28,  29).  As  to  the  assigned  character,  of  the 
animal  sarcode  being  destitute  of  a  distinct  investing  membrane  or  integu- 
ment, the  shell  produced  by  the  testaceous  forms  might  be  considered  equiva- 
lent to  one ;  and  if  some  observations  hereafter  alluded  to  be  correct,  a  re- 
sistant integument  among  the  Ehizopoda  must  be  admitted  as  an  estabhshed 
fact. 

It  is  possible  that  in  some  instances  the  organic  substance  has  a  coloiu'  of 
its  own ;  for  instance,  Ehrenberg  describes  Amoeba  pynnceps  as  having  a  yellow 
colom\  However,  in  general  the  occiuTence  of  coloiu-  is  consequent  on  that 
of  granules,  and  on  the  introduction  of  food  ;  and  obsen-ation  proves  that  the 
depth  of  coloui^  augments  ^^ith  age,  and  is  otherwise  in  direct  relation  with 
the  abimdance  of  food.  The  coloui'  is  usually  pretty  uniformly  diffused. 
Schultze  shows  this,  and  also  its  relation  with  the  thickly- distributed  minute 
granules,  in  many  Miliolidce,  Rotalidce,  and  Gromice.  In  larger  species  (he 
adds),  such  as  PoJystomella  strigilata  and  Gromia  oviformis  (XXI.  16),  the 
colour  occiu's  in  scattered  and  much  larger  particles  or  vesicles ;  yet  under 
what  form  soever  foimd,  it  is,  in  the  case  of  the  many-celled  or  chambered 
Foraminifera,  deepest  in  the  oldest  cells,  and  progressively  fades  on  aj^proach- 
ing  those  most  recently  formed,  the  last  being  commonly  quite  colourless 
(XXI.  28,  33,  36).  Experiment  also  showed  that,  by  depriving  the  animals 
of  food  wliich  could  convey  colour,  other  chambers  than  the  last  lost  their 


OF  THE  PROTOZOA. EHIZOPODA,  203 

tint,  and,  vice  versa,  that  by  feeding-  tlicm  abundantly  vnth  such  food,  even 
the  animal  substance  of  the  ultimate  cell  acquii'ed  coloiu*.  Irregular  accu- 
mulations of  colouring  particles  in  the  ultimate  chamber  are  of  rare  occur- 
rence.    Ehrenberg  has  iigiu^ed  such  in  Nonionhia  germanica. 

The  colomiess,  or  almost  colourless  Ehizopods,  principally  Amcehce,  are, 
owing  to  their  transparency,  visible  with  difficulty,  and  require  nice  adjust- 
ment of  the  microscope  and  of  the  light  to  demonstrate  their  vitality  and 
movements. 

Concerning  the  chemical  relations  of  the  organic  substance,  it  is  stained 
yellow  or  yellowish-brown  by  solution  of  iodine,  like  other  proteine  matters, 
and,  according  to  Schultze,  is  unaltered  by  diluted  acetic  acid,  is  slightly 
hardened  by  a  dilute  solution  of  the  alkahes,  and  more  so  by  one  of  the  car- 
bonates. Moreover,  its  resistance  to  chemical  action  would  seem  to  differ 
in  different  species  ;  for  the  Gromia  Dujardinii  was  the  least  affected  of  se- 
veral animals  experimented  on. 

''The  colouring-material,"  to  quote  the  same  writer,  *'  assumes  by  the  action 
of  sulphiuic  and  of  hydrochloric  acids  an  intense  verdigris  green,  and  by 
that  of  nitric  acid,  first  a  green  and  then  a  yellow  tint.  Concentrated  sul- 
phuric acid  destroys  the  colouied  substance,  but  when  combined  -svith  sugar, 
renders  it  green.  By  concentrated  solutions  of  potash  and  soda,  the  coloui'ed 
granules  are  dissipated  without  change  ;  and  in  ether  and  alcohol  they  are 
readily  and  completely  dissolved.  In  these  reactions  the  coloming-matter 
agrees  with  Diatomece,  from  which,  no  doubt,  it  is  derived  in  the  form  of  food." 

jS'o  definite  figure  can  be  said  to  belong  to  the  animal  portion  of  the  Rhi- 
zopoda,  owing  to  its  capability  of  thro'wdng  out  processes  in  every  direction, 
of  various  dimensions  and  in  different  numbers,  changing  them  almost  every 
moment.  Auerbach,  however,  asserts  of  the  Amcehce  that  they  have  normally 
a  spherical  figiu^e.  Dr.  Bailey  has  pointed  out  the  influence  of  pressure  from 
within,  due  to  the  various  articles  swallowed,  in  modifying  the  figure.  The 
Amoebce,  being  untrammelled  by  a  shell,  exhibit  the  Protean  changes  of  form 
in  the  highest  degree,  whilst  the  completely  enclosed  Foraminifera  present 
them  in  the  lowest.  In  the  latter  the  organic  mass  must  follow  the  windings 
of  the  canity  of  the  shell  (XXI.  24),  and  can  escape  only  from  the  foramina 
(holes)  as  thread-hke  filaments,  in  the  form,  extension,  and  subdivisions  of 
which  great  latitude  prevails.  We  have  said  that  the  sarcode  of  FoJythala- 
mia  follows  the  windings  or  adapts  itself  to  the  figure  of  each  segment  of  the 
shell,  and  has  actually  no  figure  of  its  own.  However,  when  separated  from 
its  calcareous  investment  by  means  of  an  acid,  it  retains  the  outline  originally 
imposed  on  it.  ThiLS  (XXI.  24)  Schultze  exliibits  the  sarcode  substance  of  a 
Miliola  so  separated,  which  shows  a  constriction  at  each  half  turn  of  the  spii^al 
and  the  deheate  membrane  which  invests  it  or  lines  the  shell.  So,  again.  Dr. 
Carpenter,  in  his  description  of  Orhitolites,  states  that  the  soft  sarcode  body  is 
made  up  of  a  number  of  segments  equal  and  similar  to  each  other,  and  arranged 
in  concentric  zones  around  a  central  nucleus.  Among  the  Amcehce  the  varia- 
ble processes  may  either  be  protruded  at  one  time  from  eveiy  portion  of  the 
little  mucous  mass,  so  that,  as  Ehrenberg  remarks  of  the  Amoeba  rcaJiosa,  it 
may,  when  fully  outspread,  be  likened  to  a  miniatm-e  porcupine ;  or,  othei-wise, 
they  may  be  produced  chiefly  or  entirely  from  one  side ;  or,  as  when  the  ani- 
mal is  moving,  they  are  thrown  forward  in  the  direction  it  is  progressing,  and 
retracted  on  the  opposite  side.  Among  many  Monothalamia  the  bulk  of  the 
Hying  mass  issues  through  the  one  large  orifice,  and  can  spread  out  in  a  similar 
manner  to  the  free  Amoehhia, — the  shell,  according  to  the  direction  of  the 
pseudopodes,  resting  in  the  centre  of  the  mesh  or  on  one  side.  The  Forami- 
nifera have  a  like  capacity  of  extruding  their  processes  in  one  direction  rather 


204  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

than  in  another,  or  in  all  directions  together ;  and  acciiraulations  of  their 
mucous  substance,  or  fusions,  may  take  jjlace  on  any  one  side.  In  this  family 
the  fiHform  fibres  are,  as  a  rule,  not  seen  protruded  at  any  one  time  through 
all  the  pores  perforating  the  shells. 

Many  genera  have,  besides  the  generally- distributed  small  foramina,  a  larger 
orifice  in  the  ultimate  chamber  ;  such  is  seen  in  Botalia  and  Textilaria.  In 
these,  says  Schultze,  it  may  be  remarked  that  the  jDi'ocesses  fii'st  throAvn  out 
come  principally  from  the  large  openings,  and  frequently  a  considerable  time 
elapses  before  the  numerous  fine  pores  give  exit  to  fibres.  Often,  again,  the 
filaments  are  extended  only  from  the  two  or  three  last-formed  cells.  Yet 
after  long  lying  imdistiu-bed,  fibres  may  be  seen  proceeding  from  eveiy  part 
of  the  surface  of  the  finely  porous  shells.  Still  the  question  requires  further 
examination,  to  decide  whether  the  processes  can  be  extruded  through  all  the 
foramina  or  only  thi'ough  some  of  them  in  certain  places.  However,  as 
Schultze  remarks,  the  universal  porosity  would  seem  without  a  purpose  if  it 
does  not  give  vent  to  the  contained  substance  at  all  points. 

The  processes  of  PoJytliaJamia  attain  the  greatest  length  and  fineness,  and 
often  constitute  a  network  of  several  hues  in  diameter, — the  shell  of  the  ani- 
mal occupying  the  centre,  like  a  sj^ider  lodged  in  the  middle  of  its  web.  The 
length  of  such  fibres  not  imcommonly  exceeds  twelve  times  the  diameter  of 
the  shell.  The  processes  of  most  Monotludamia  are  not  so  numerous,  and  do 
not  equal  on  an  average  those  of  the  Pol y thai cmiia,  whilst  those  of  the  Amoebce 
are  mostly  shorter  and  broader.  The  length,  number,  and  fineness  of  the 
processes,  together  with  theii'  mode  of  termination,  supply,  under  considera- 
ble hmitations,  characters  for  distinguishing  species  chiefly  of  the  Amcebina, 
and,  in  a  less  degree,  of  the  single- chambered  testaceous  Rhizopoda. 

The  ever-fluctuating  form  of  the  animal  mass  and  of  its  processes  is  ex- 
pressed by  the  term  "■  ijolymorphism,''''  It  is,  as  before  noticed,  a  well-marked 
character  of  Bhizoj^oda,  although  not  restricted  to  them  ;  for  the  like  is  exhi- 
bited by  the  yolk-cells  of  Planaria,  and  by  detached  fragments  of  the  substance 
of  Hydra ;  in  fact,  illustrations  are  not  wanting  in  the  vegetable  kingdom. 

The  phoenomenon  of  polymorphism  would  seem  to  discountenance  the  hy- 
pothesis of  the  presence  of  a  limiting  membrane  or  skin.  Ehrenberg  described 
a  resistant,  very  elastic,  and  contractile  integument,  and,  to  explain  the  vaii- 
abihty  of  figure  and  the  extension  of  the  pseudopodes,  supposed  a  relaxation 
or  suspension  of  the  natm^al  contractility  of  the  integ-ument  at  the  extending 
point,  and  a  consequent  passive  yielding  before  a  pressure  from  within  exerted 
by  the  contained  substance.  This  explanation  he  endeavoured  to  illustrate 
by  comparing  the  process  with  the  formation  of  a  hernia  or  rupture, — a  com- 
parison, by  the  way,  involving  an  effort  of  imagination  to  discover  any  simi- 
larity between  the  two  occurrences.  Thus  he  remarks  of  Aiyioeha  princeps 
that  "  its  normal  shape,  if  such  it  can  be  said  to  possess,  is  globular ;  but  it 
can  relax  any  portion  of  its  body,  and  contract  the  rest,  so  as  to  force  the  in- 
ternal substance  do'wn  into  this  relaxed  portion,  which  thus  becomes,  as  it 
were,  a  hernial  tumour."  This  notion  is  opposed  by  the  results  of  observa- 
tion. The  very  characters  of  the  processes,  their  great  length  and  frequent 
tenuity,  their  branching,  adhesion,  and  coalescence  contradict  the  assimip- 
tion  ;  and  the  fact  of  their  not  uncommon  extensoin  from  all  sides  of  an  ani- 
mal involves,  as  a  consequence  of  Ehrenberg' s  hypothesis,  a  behef  in  the 
exertion  of  internal  pressure  in  opposite  dii-ections  at  the  same  time.  Other 
evidence  of  the  error  of  this  h5q)othesis  is  found  in  the  following  facts,  ^dz. 
the  adhesion  and  entrance  of  foreign  bodies  at  any  part  of  the  sarcode  sub- 
stance, the  cohesion  of  two  individuals,  and  that,  as  pointed  out  by  Dujardin, 
when  the  gelatinous  mass  of  an  Amoeba  is  torn  or  cut  across,  no  escape 


OF  THE  PROTOZOA.-— EHIZOPOD A.  205 

of  a  contained  softer  matter  or  of  grannies  takes  place,  but  each  segment  con- 
tracts on  itself  and  continues  to  live,  and,  again,  that  when  a  Rhizopod  is 
shaken  about,  its  processes  become  flexuous,  and  float  loosely  instead  of  being 
vvithdi'avvn  within  the  general  mass,  as  should  happen  if  a  general  contractile 
integument  enveloped  it.  Among  the  Amabel  generally,  a  distinct  hyaline 
cortical  substance  is  found  enveloping  the  interior  more  fluid  matters,  and 
restraining  their  escape.  (See  afterwards,  on  shells  of  MonotliaJamia,  excep- 
tional forms  noticed  by  Dujardin  and  Bailey,  and  the  researches  of  Auerbach.) 

Although  an  integument  be,  therefore,  no  part  of  the  structui^e  of  Rhizopoda, 
yet  their  soft  substance  is  capable,  as  is  shown  best  in  the  Amoeb'ina,  of  resist- 
ing internal  pressure,  such  as  that  from  silicious  shells  of  DiatomecB  and  other 
hard  substances,  which  oftentimes  cause  irregular  and  sharp  projections  during 
the  movements  of  the  animals,  but  yet  very  rarely  perforate  them.  On  the 
other  hand,  Rhizopoda  become  sometimes  impaled  upon  the  rigid  fibres  of 
plants  or  other  substances,  and,  though  thus  transfixed,  will  move  fi'om  one 
extremity  to  the  other,  without  any  apparent  inconvenience  or  injury.  This 
cii'cumstance  has  been  long  noticed  in  the  case  of  the  Amoehce ;  and  Schultze 
has  figured  a  specimen  of  a  testaceous  Rliizopod — the  Gromia  Dujcuxlinii 
— penetrated  by  a  large  curved  hair. 

Dr.  Auerbach,  in  a  recent  Essay  on  the  AmoehaKi  {Zeitsclir.  1855,  pp.  365- 
430),  has  advanced  the  statement,  from  observation,  that  all  the  Amcebce  are 
enclosed  by  an  adhesive,  elastic  and  structureless  membrane  or  integument. 
This  fact  has,  he  says,  been  so  universally  overlooked  by  reason  of  the  diffi- 
culty in  determining  it,  and,  where  caught  sight  of,  has  been  misinter- 
preted, as,  for  instance,  by  Schneider  {Midler's  Arcliiv,  1854,  p.  201),  who 
represents  Amoeba  enclosed  by  a  membrane  as  being  in  a  state  of  "  rest,"  or 
encysted. 

Auerbach  makes  particular  reference  to  two  new  species  discovered  by  him, 
as  illustrative  of  the  presence  of  an  integument,  ^dz.  A.  bilimbosa  (XXII.  7- 
11),  and  A.  act'mojyliora  (XXII.  13),  in  both  of  which  he  detected  a  double 
peripheral  line.  But  besides  this  e\idence  he  appeals  to  the  eff'ects  of  reagents, 
of  acetic  or  of  diluted  sulphuric  acid  and  alkahne  solutions,  both  on  the  species 
just  cited  and  on  others  well  known — for  instance,  A.  iirinceps — in  demon- 
strating the  membranous  investment.  And  what  seems  at  least  very  strange, 
we  might  say  quite  inexplicable,  he  asserts  that  upon  all  the  processes,  how- 
ever branched,  anastomotic,  or  fine,  this  membrane  is  extended  to  their  very 
extremities ;  for  on  adding  a  dilute  alkaline  solution  to  Amoeba  radiosa,  the 
granidar  and  molecular  contained  mass  became  shrunken,  and  retreated  to- 
wards the  centre,  leaving  the  figm^e  of  the  animalcule  with  all  its  processes 
as  before  the  addition,  the  latter  appearing  as  tubules  mth  closed  ends,  which 
ruptured  by  over- extension. 

This  same  author  accoimts  for  the  entrance  of  solid  particles  from  without 
by  imagining  the  integument  to  rupture  to  receive  them,  and  then  to  close  on 
them  so  as  to  leave  no  trace  of  the  proceeding.  Fui^ther,  the  membrane  is 
not  soluble,  at  the  ordinary  temperature,  in  acetic  nor  in  mineral  acids,  nor 
in  dilute  alkaline  solutions,  and  therein  agrees  with  the  tissue  noticed  by 
Cohn  in  Paramecium  and  other  Ciliata  {vide  chap,  on  Ciliata),  and  with  the 
cell-membrane  of  animal  cells. 

These  observations  of  Dr.  Auerbach  are  well  deserving  attention,  although 
we  are  indisposed  to  accept  them  in  their  entirety.  The  wonderful  poly- 
morphism, the  coalescence  of  processes,  and  the  particulars  alluded  to  above 
(p.  204)  as  inconsistent  with  the  presence  of  an  integument  need  not  be 
again  adduced  in  argument.  What  is  desirable  is,  that  observations  should 
be  multiplied  on  this  subject,  which  is  one  that  strongly  commends  itself  to 


206  GENEEAL  HISTORY  OF  THE  INFUSOEIA. 

the  notice  of  microscopists  on  account  of  its  bearing  on  the  question  of  cell- 
constitution. 

The  variable  processes  serve  the  Rhizopoda  for  locomotive  organs.  An  ex- 
pansion is  thro^vn  out  in  advance,  into  which  a  constant  influx  of  the  sarcode 
substance  sets, — whilst  in  the  opj^osite  direction  a  counter- current  occurs, 
effecting  the  retraction  of  the  posterior  processes.  This  onward  flow  of  the 
substance  of  the  body  proceeds  until  at  length  the  whole  is  transferred  into 
the  advanced  process,  mo^dng  from  its  base  to  its  termination.  In  this  manner 
the  animal  progresses,  the  space  passed  over  equalling  the  length  of  the  ex- 
pansion it  protrudes.  This  method  of  locomotion  may  be  designated  creep- 
ing or  crawling,  and  is  the  only  one  with  which  this  class  of  animals  is  en- 
dowed. The  consequence  is  that  they  are,  as  a  rule,  to  be  only  foimd  adherent 
to  solid  bodies,  and  cannot  move  by  swimming.  However,  they  can  move  as 
passive  particles  of  matter,  be  rolled  along  by  currents  upon  any  substance 
they  are  in  contact  with,  or,  from  being  (as  in  the  case  of  Amoeba)  of  almost 
the  same  specific  gra\'ity  with  the  water  in  which  they  hve,  may  float,  or  be 
suspended  in  it  for  a  long  time.  Theii^  motion  by  creeping  is  exceedingly 
slow,  and  oftentimes  is  appreciable  only  by  attentive  watching. 

The  graphic  description  of  Schultze,  of  the  expansion  of  processes  in  a  naked 
Amoeba  and  in  a  testaceous  species,  viz.  the  Gromia  oviformis,  will  make  the 
phaenomenon  more  distinct.  The  former  is  a  new  species  discovered  and  named 
by  himself  the  Amoeba  porrecta  (XXI.  3).  It  is  distinguished  from  other 
species  in  the  genus  by  the  great  extension  it  is  capable  of,  and  by  the  lively 
motile  energy  of  its  contractile  substance.  "  It  sends  out  from  its  colourless 
body,  on  all  sides,  numerous  fibrous  processes,  short  and  broad  on  theii'  fii\st 
extrusion,  but  which  gradually  elongate  until  they  exceed  the  diameter  of 
the  body  eight  or  ten  times,  and  taper  to  such  fine  extremities  that  a  mag- 
nifying power  of  400  diametei^  is  needed  to  distinguish  them.  The  figui'e 
and  extension  of  the  body  change  every  moment,  according  to  the  side  in 
which  the  ramifications  are  extended.  If  two  or  more  of  the  filiform  pro- 
cesses touch,  a  coalescence  takes  place,  and  broader  plates  or  net-like  inter- 
lacements are  produced,  which,  in  the  continual  changes  of  figm^e,  are  either 
taken  up  again  into  the  general  mass,  or  otherwise  are  fui'ther  increased  by  a 
fresh  influx  of  matter,  until  finally  the  entire  body  is  transposed  to  their  place." 

In  the  testaceous  Gromia  ovifornnis  (XXI.  16),  after  a  state  of  rest  of  some 
dm^ation,  fine  fibrous  processes  are  seen  to  be  extended  from  the  single  large 
opening  of  the  shell,  which,  on  their  first  extrusion,  move  about  in  a  groping 
manner  until  they  lay  hold  of  some  solid  body  (such  as  the  siuface  of  the  glass 
slide)  on  which  they  may  stretch  themselves  out,  receiving  in  the  meanwhile 
new  matter  from  within  the  shell.  The  first  fibres  are  extremely  fine  ;  but  pre- 
sently they  grow  wider,  and  proceed  to  elongate  themselves,  pm^suing  a  straight 
course,  ramifj-ing  in  their  own  way  and  coalescing  with  adjoining  processes, 
until,  becoming  progressively  finer  and  finer,  they  attain  a  length  exceeding 
that  of  the  body  six  or  eight  times.  The  fibres  having  now  outstretched 
themselves  in  eveiy  dii^ection,  and  absorbed  the  greater  part  of  the  finely- 
granular  contractile  substance,  their  further  extension  in  length  ceases. 
However,  the  reticulations  go  on  miiltiplying ;  numerous  bridges  (inoscula- 
tions) are  estabhshed  between  them ;  and  by  the  continued  changes  of  position 
a  constantly  shifting  protean  web  is  produced,  where  a  greater  number  of 
fibres  come  together  at  the  periphery  of  the  sarcode-net  as  we  may  term  it, 
broader  plates  (lanunae)  of  the  perpetually-flowing  substance  are  formed,  from 
which  again  new  filaments  are  pushed  out  in  new  directions,  as  if  it  were  a 
separate  Amoeba.  In  the  PoJi/stomelhe,  the  long  fibres  are  seen  to  converge 
to  form  a  pyramidal  i)undlc,  and  to  coalesce  into  wide  laminte  at  its  apex. 


OF  THE  PROTOZOA. EHIZOrODA.  207 

Dujardin  made  some  precise  observations  respecting  the  characters  of  the 
locomotive  variable  processes  and  the  rate  of  movement.  In  Gromia  oviformis, 
he  describes  a  filament  to  begin  as  a  very  fine  simple  and  imiform  offshoot, 
which  elongates  and  directs  itself  in  different  directions,  in  order  to  seek  a 
point  of  attachment ;  sometimes  it  oscillates,  at  others  it  exhibits  a  tolerably 
rapid  nndiilatory  movement,  or,  otherwise,  it  rolls  itself  up  in  a  spiral  manner, 
when  the  several  coils  coalesce,  and  a  mass  is  formed  capable  of  throwing  out 
afresh  other  processes.  Proportionately  to  the  extension  of  the  filament,  its 
substance  is  added  to  by  an  afliux  of  new  substance  from  the  chief  mass,  evi- 
denced by  the  movement  of  irregular  granules,  which  give  the  fibres  an  un- 
equal and  nodose  appearance.  Moreover,  the  fibre  gives  off  branches  here  and 
there  at  a  more  or  less  acute  angle,  which,  in  theii'  tui-n,  ramify  after  the  same 
fashion,  and  establish  communications  or  anastomoses  with  one  another.  Often 
also  films  or  laminte  of  the  gelatinous  substance  form  at  the  extremities  of 
contiguous  fibres,  which  extend  themselves  variously.  The  filaments  retreat 
by  an  inverse  movement ;  and  this  is  occasionally  so  sudden  that  the  end  as- 
sumes a  button-like  termination  from  the  fusion  of  the  mass  of  matter  engaged 
in  its  formation. 

The  expansions  of  M'dlola,  he  fiu'ther  tells  us,  are  six  times  finer  than  those 
of  Gromia,  and  the  movement  of  the  animal  more  rapid ;  for  during  summer 
it  moves  from  about  -^^ih  to  ^th  of  an  inch  in  an  hoiu-.  CristeUaria  moves  -J-th 
of  an  inch,  and  Vorticicdis  from  -^th  to  -^rd  of  an  inch  in  a  like  period. 

The  variable  processes  also  constitute  the  prehensile  organs  of  the  Rhizo- 
poda.  Any  small  objects  serviceable  for  nutrition,  with  which  they  come  into 
contact,  are  laid  hold  of  by  them  apparently  by  means  of  their  viscid  surface ; 
and,  except  they  are  animalcules  of  considerable  size  and  power,  they  are  un- 
able to  escape.  When  a  filament  or,  as  we  may  call  it  ^vith  reference  to  this 
function,  a  tentacle  has  so  seized  its  prey,  adjoining  fibres  aggregate  about 
it  and  coalesce,  a  current  of  the  viscous  substance  sets  in  towards  the  spot, 
and  very  soon  envelopes  the  object  by  a  fJm.  The  prey  being  thus  secured, 
the  processes  shorten  themselves  and  di^aw  it  towards  the  chief  mass  or  body 
of  the  animal,  or,  otherwise,  the  object  seized  continues  in  the  same  i>lace,  and 
the  whole  organic  substance  moves  towards  it, — the  result  being  in  either  case 
that  it  is  engulfed.  In  the  Amoehina  this  prehensile  act  proceeds  as  just 
stated;  in  the  Monothalamia  and  in  those  Foraminifera  having  a  large 
opening  in  the  last  chamber,  the  body  seized  is  directed  to  the  large  orifice 
of  the  shell ;  but  in  those  having  no  other  than  fine  pores  or  minute  fissures, 
it  would  not  seem  to  reach  the  general  mass,  but  to  be  used  up  for  the  jDur- 
poses  of  nutrition  externally  to  the  shell,  by  a  digestive  action  inherent  in 
the  fibres  themselves.  The  mode  of  entrance,  therefore,  of  food  within  the 
Aiscid  organic  matter,  is  not  so  simple  and  mechanical  an  act  as  Dujardin  re- 
presented it,  but  has  much  mxore  of  a  vital  character.  This  observer's  state- 
ment was,  that  the  mere  pressure  of  the  body  of  the  animal  on  the  smface  it 
moved  over  caused  the  penetration  of  foreign  matters,  which,  by  subsequent 
extensions  and  contractions  of  different  parts  of  the  substance,  became  at 
length  completely  involved  in  it.  It  would  seem  that  animalcules  may  swim 
about  unharmed  within  the  meshes  of  the  sarcode-web,  but  that  so  soon  as 
they  touch  one  of  its  fibres,  they  are  as  it  were  paralysed  and  incapable  of 
further  motion,  and  are  consequently  dra^^m  deeper  into  the  net  without  any 
opposition.  Sehultze,  who  has  noticed  this  circumstance,  believes  it  to  be 
quite  exphcable  as  a  simple  mechanical  act,  and  no  proof  of  a  special  be- 
numbing property  resident  in  the  soft  substance  as  Ehrenberg  was  inclined 
to  suppose.  Food,  or  indeed  any  extraneous  matters,  may  enter  the  soft 
bodies  of  Rhizopoda  at  any  point  of  their  surface  ;  ?.  e.  in  other  words,  those 


208  GENERAL  HISTORY  OF  THE  INFUSORIA, 

animals  have  no  definite  aperture  for  food — no  mouth.  This  absence  of  a 
mouth,  on  anatomical  grounds  alone,  involves  that  of  an  alimentaiy  canal,  or 
of  a  polygastric  structure  such  as  Ehrcnberg  imagined.  The  digestive  cells, 
so  called,  of  Arcellina  are  nothing  more  than  hollow  spaces  or  vacuoles  (XXII. 
7,  8,  9),  which  spontaneously  and  irregularly  develope  themselves  in  the  mu- 
cous sarcode  substance.  They  especially  make  their  appearance  after  the  in- 
troduction of  food,  the  particles  of  which  generally  appear  enclosed  within 
them,  and  to  be  surrounded  by  a  fluid.  In  the  allied  organisms  represented 
by  Actinophrys,  M.  Claparede  states  that  the  particle  of  food  always  hes  in  a 
cavity  filled  with  fluid — a  vacuole, — and  that  the  fluid  is  of  a  pale  reddish 
colour,  with  difterent  refractive  powers  to  those  of  water,  and  is  in  all  proba- 
bility a  solvent  or  digestive  fluid.  This  pale-red  or  reddish-yeUow  tint  of 
the  vacuoles  is  remarked  also  in  Amoehoi ;  and  the  observed  dissolution  and 
eventual  disappearance  of  organic  matters  absorbed  is  a  sufficient  proof  of 
the  presence  of  a  digestive  secretion.  In  an  Arcella  vulgaris,  Perty  witnessed 
the  successive  appearance  of  four  vacuoles,  each  in  its  tiu^n  enlarging  from  a 
small  roimd  to  a  large  reniform  space,  and  thereby  expanding  the  dimensions 
of  the  animal  itself.  He  believed  them  to  be  filled  with  air,  and,  like  the 
air-bladders  of  fish,  to  serve  to  float  and  tm^n  the  animals  in  the  water,  when 
free  and  without  solid  objects  to  crawl  upon. 

Ehrenberg  states  that  in  some  Arcellina,  where  "  digestive  sacs "  were 
otherwise  invisible,  they  were  brought  into  view  by  feeding  the  animals  with 
coloured  substances.  He  thus  presumed  on  the  prior  existence  of  these  cells, 
supposing  the  colouring  particles  to  be  merely  the  means  of  bringing  them 
into  view.  The  true  explanation,  however,  is,  no  doubt,  that  the  con- 
struction of  vacuoles  is  consequent  on  the  introduction  of  food,  and  de- 
pendent on  the  manner  in  which  the  animal  substance  enfolds  the  solid  par- 
ticles which  it  has  seized.  Obsei-vation,  indeed,  proves  that  the  vacuoles 
have  no  constant  and  definite  existence  and  position ;  for  they  coUapse  and 
disappear  when  the  contents  are  removed  or  are  reduced  to  a  few  fine 
granules  dispersable  in  the  common  mass.  They  also  constantly  shift  their 
position,  and  not  unfrequently  make  their  way  to  the  siuface,  at  which  they 
bluest  and  disappear.  As  Dujardin  also  remarks,  they  sometimes  form  at  or 
near  the  surface,  and  may  even  serve  as  a  medium  for  introducing  foreign 
matters  into  the  body. 

Dr.  Bailey,  in  his  description  of  a  new  species  which  he  names  pampTiagus, 
represents  it  as  having  (although  a  shell-less  Rhizopod)  a  mouth  from  which 
alone  pseudopodes  protrude,  and  a  single  stomach  ;  hence,  he  adds,  it  cannot 
be  considered  po7^(7asfr?c.  However,  no  evidence  is  adduced  to  support  this 
notion  of  a  gastric  cavity ;  on  the  contrary,  indeed,  the  details  given  stand 
opposed  to  such  an  hypothesis, — for  instance,  to  quote  only  one,  that  of  their 
being  frequently  seen  transfixed  by  dehcate  fibres  of  foreign  matters,  and 
moving  unharmed  up  and  down  them. 

Schultze  states  that  in  Foraminifera  veiy  clear  vesicles  are  uniformly 
diffused  throughout  the  body,  some  entirely  homogeneous,  others  finely 
granular,  or  filled  mth  corpuscles.  However,  nuclear  corpuscles,  which  can 
be  regarded  as  cells  in  the  ordinary  signification,  are  never  found.  This 
naturalist,  moreover,  indicates  the  existence  of  a  larger  species  of  vesicles  in 
Gromia  oviformis  (XXI.  16),  containing  other  clear  corpuscles,  sometimes  to 
the  number  of  eighteen,  but  never  strung  together  ;  he  believes  Kkewise  that 
similar  vesicles  exist  among  other  Fora^nimfera,  and  seems  disposed  to  attri- 
bute to  them  a  nuclear  character. 

Ehrenberg  professed  to  discover  in  the  Polytlialamia,  in  each  chamber, 
saving  the  last,  an  alimentary  tube,  having  a  greyish-green  colour  and  very 


OF  THE  PEOTOZOA. RHIZOPODA.  209 

thick.  This  intestinal  cavity,  he  affirmed,  communicated  with  the  cell  in 
front,  and  the  one  next  behind  it  by  a  narrower  canal — the  siphon, — and 
that  in  this  manner  a  sort  of  continuous  moniliform  intestine  was  produced, 
extending  from  the  primary  to  the  penultimate  cell.  He  adds  that,  after  the 
solution  of  the  shell  of  Nonionina  Germanica  by  dilute  acid,  various  sihcious 
Infusorial  shells  could  be  seen  within  this  digestive  tube,  as  far  back  in  the 
animal  as  the  fii^st  chamber.  Moreover,  he  was  fortunate  enough  to  be  able, 
after  the  dissolution  of  the  shell  of  Rotalia  by  acid,  and  by  proceeding  very 
gradually,  to  set  fi'ee  an  internal,  spiral,  jointed  body,  the  segments  of  which 
were  strung  together  in  Nonionina  by  one,  and  in  Geojoonus  by  fi^om  18  to 
20  tubes  (siphons)  ;  strong  acids  destroyed  the  shell  so  rapidly  that  the  con- 
tained delicate  body  became  broken  up  into  many  insignificant  fragments.  In 
none  did  he  succeed  in  introducing  coloured  food.  This  digestive  apparatus 
others  have  sought  in  vain  in  the  Foyximinifera.  The  spiral  articulate  body 
extracted  by  the  Berlin  naturalist  from  the  shell,  was  undoubtedly  nothing- 
more  than  the  soft  animal  contents,  somewhat  acted  on  by  the  acid,  such  as 
Schultze  has  pictured  from  the  cavity  of  a  Miliola  (XXI.  24). 

Eespecting  the  penetration  of  food  to  the  primordial  chamber,  which  Ehren- 
berg  imagined  he  had  seen  in  Nonionina,  Schultze  observes  that,  among  the 
many  beings  he  has  examined,  he  has  not  detected  nutritive  matters  fiu'ther 
back  than  the  second  or  third  cell. 

The  substances  received  from  without,  after  ha\dng  served  their  purpose 
within  the  gelatinous  body  of  Ehizopoda,  make  their  way  outwards  and 
escape  from  any  part  of  the  siu-face, — an  anus  being,  like  the  mouth,  pro- 
duced temporarily,  at  any  point  whatever,  where  matters  present  themselves 
for  discharge. 

The  materials  taken  within  the  body  of  Rhizopods  are  most  heterogeneous  ; 
no  selecting  power  being  displayed  by  the  animals,  various  Ciliated  Protozoa, 
fragments  of  the  filaments  and  spores  of  Algae,  frustules  of  Diatomece  and 
Desmidiece,  even  Rotatoria,  fall  a  prey :  but  along  with  these,  from  which 
nutriment  may  be  extracted,  are  other  substances  which  can  be  supposed  to 
serve  no  useful  purpose ;  such  are  particles  of  sand,  morsels  of  woollen  and  of 
cotton  tissues,  and  the  like.  The  introduction  of  particles  indiscriminately 
is  explicable  from  the  mode  in  which  they  are  eaptm^ed  by  the  filamentary 
arms,  which  seem  to  act  in  a  prehensile  manner,  on  feeling  the  contact  of  any 
foreign  object,  be  that  what  it  may. 

Dujardm  threw  doubts  upon  the  nutritive  purpose  of  the  solid  objects 
swallowed,  and  supposed  the  act  of  nutrition  consisted  in  the  simple  imbibition 
or  endosmosis  of  fluid  from  without.  "  It  is,"  he  writes,  ^'  difiicult  of  belief 
that  these  included  particles,  by  reason  of  their  consistence  and  the  unalter- 
abihty  of  many  of  them,  can  serve  to  nourish  the  Amoebce  ;  yet,  whilst  admit- 
ting that  they  are  nourished  by  absorption,  I  would  not  deny  that  they  may 
find  means  of  stiU  more  readily  appropriating  nutritive  materials,  by  swallow- 
ing various  foreign  bodies,  and  by  so  increasing  their  absorbent  surface."  The 
evidence  of  direct  observation,  hov\^ever,  is  in  favour  of  the  conclusion  that 
the  substances  received  within  the  simple  animal  mass  actually  afford  ma- 
terials for  its  nutrition.  The  contents  are  ever  changing  and  making  their 
exit  from  it ;  and  an  act  of  digestion  or  of  solution  is  perceptible — slow,  indeed, 
even  when  soft  Ciliated  Protozoa  are  the  subjects.  Thus  animalcules,  when 
within  the  sarcode  mass,  are  first  compressed  into  small  balls ;  the  distinct- 
ness of  their  parts  then  fades,  and  they  are  presently  converted  into  small 
gelatinous  globules,  which  in  due  course  disappear,  from  amalgamation  with 
the  enclosing  substance.  Where  the  included  body  consists  partially  of 
insoluble  material,  this  remains  behind  in  the  form  of  fine  granules,  or,  in 

p 


210  GENERAL  HISTORY  OF  THE  INFUSORIA. 

the  case  of  the  silicious- enveloped  Diatomece,  the  dense  skeleton,  emptied 
of  its  organic  contents,  continues  visible  for  a  longer  or  shorter  time.  The 
robbing  of  the  frustules  of  Bacillaria,  and  the  appropriation  of  their  coloured 
endochrome,  has  been  referred  to  in  the  foregoing  remarks  on  the  colouring  of 
Rhizopoda  (p.  203)  by  the  green  colouring-matter  of  plants. 

The  Rhizopods  Bailey  describes  were  met  with  in  a  vivarium,  into  which 
"  bits  of  boiled  beans  and  potatoes  had  occasionally  been  introduced  as  food 
for  other  animalcules ; ....  on  the  application  of  tincture  of  iodine  to  these 
animals,  a  distinct  blue  colour  was  often  seen  diifused  over  the  whole  surface 
of  many  of  the  grains  of  sand  in  their  stomach." 

The  above  facts — to  which  we  may  add  another,  viz.  that  the  abimdance  of 
granules  in  the  interior  is  in  direct  proportion  with  that  of  food — furnish 
sufficient  proof  of  the  occurrence  of  a  digestive  faculty,  and  of  a  power  of 
assimilation  among  the  Ehizopods.  This  imphes  the  existence  both  of  a 
digestive  fluid,  and  of  a  secretory  fimction ;  the  latter,  too,  is  further  ex- 
emplified by  the  production  of  shells  in  the  majority  of  the  class. 

Auerbach  (op.  cit.  p.  422)  distinguishes  two  leading  varieties  of  granules  in 
Amoehce : — one  of  a  pale  colour  and  finely  di^dded,  and  either  soluble  in 
alkalies  and  acids,  and  tui'ned  brown  by  iodine,  or,  more  rarely,  insoluble  in 
alkalies ;  the  other,  dark  in  hue,  strongly  refracting,  and  usually  corre- 
spondent in  number  and  relative  size  with  the  animalcules  to  which  they 
appertain.  These  latter  have  the  aspect  of  fat-molecules ;  are  spherical  or 
elliptic,  or  at  times  crystallized  in  a  rhombic  form ;  and  they  are  easily  soluble 
in  cold  alkaline  solutions,  and  more  slowly  so  in  concentrated  acetic  and  sul- 
phuric acids.  In  one  species,  A.  bilimhosa,  he  met  with  starch  globules ;  but 
these  were  probably  of  extraneous  origin. 

Movements  of  contained  particles. — Every  movement  of  the  mucous  sub- 
stance of  Khizopoda  is  accompanied  by  one  of  the  granules,  and  of  the  small 
vesicles  or  globules  contained  within  it.  This  motion  of  the  contents  follows 
a  certain  course,  and  is  especially  observable  in  the  outstretched  variable  pro- 
cesses. Schultze  thus  describes  it  in  the  large  Amoehctpor recta  : — ''  A  continued 
current  of  the  granules,  imbedded  in  the  contractile  substance,  accompanies  all 
these  phenomena  {yiz.  of  polymorphism) ;  and,  in  the  processes,  this  cuiTcnt 
follows  two  directions  ;  thus  the  globules  may  be  seen  advancing  on  one  side, 
towards  the  end  of  the  process,  when  they  turn  round  to  the  other,  and  are 
carried  Tvith  a  comparatively  more  rapid  motion  back  towards  the  base  of  the 
filament,  where  they  are  lost  in  the  substance  of  the  body,  unless  they  happen 
to  meet  another  stronger  stream  by  which  they  are  reconveyed  through  the 
same  circuit."  A  precisely  similar  phenomenon  is  witnessed  in  the  testaceous 
E-hizopods.  Thus  in  Gromia  oviformis,  Schultze  says,  the  granules  are  seen 
to  depart  from  the  substance  within  the  shell  to  the  end  of  the  filaments,  and 
thence  to  retui^n  again  to  the  point  from  which  they  set  out.  This  circula- 
tion goes  on  in  every  process ;  but  it  is  in  the  broader  filaments,  containing 
numerous  granules,  that  the  double  stream  is  chiefly  visible  :  for  in  the  finer 
ones,  whose  diameter  is  often  less  than  that  of  some  of  the  corpuscles,  it  is 
more  rarely  seen ;  in  fact,  in  the  latter  the  granules  seem  not  to  be  included 
within  the  substance,  but  to  be  transported  on  the  surface.  Oftentimes  a 
corpuscle,  on  arriving  at  a  point  where  a  fibre  bifiii'catcs,  is  arrested  for  a 
time,  until  di^awn  into  one  or  other  current, — whilst  at  the  bridge-like  con- 
nexions between  adjoining  filaments,  where  the  granules  pass  across  from 
one  to  the  other,  it  not  unfrequently  happens  that  they  are  transferred  from 
a  centrifugal  to  a  centripetal  stream,  and  are  consequently  turned  back  again 
towards  the  body.  Moreover,  in  the  broader  processes,  granules  are  observed 
to  come  to  a  stand,  to  oscillate  for  a  time,  and  at  length  to  take  a  retrograde 


OF  THE  PROTOZOA. RHIZOPODA.  211 

coui'se.  Since  there  is  no  appreciable  distinction  of  tissues,  not  even  of 
integument  and  contents,  the  existence  of  vessels  to  account  for  these  cui^- 
rents  cannot  be  presumed. 

A  cimous  exception  appears  to  exist  in  Gromia  Dujardhiii,  the  filaments 
of  which  exhibit  no  granules,  but  are  perfectly  hyaline,  and  moreover  show 
no  circulation.  In  their  transparency,  Sohultze  remarks,  they  resemble  the 
processes  of  Arcella  and  Diiffiugia,  and  so  also  in  the  matter  of  breadth,  but 
differ  by  their  greater  length,  their  finely-pointed  extremities,  and  by  their 
frequent  ramifications.  This  species  has  also  in  its  principal  mass  pecuKar 
coipuscles,  roimd,  oval,  or  iiTegular  in  figure,  with  a  sharp  outline,  and  of  a 
bro"svn  coloiu-,  differing  fi^om  all  other  known  elementary  particles  in  chemical 
reaction,  in  resistance  to  alkaline  solutions,  and  to  mineral  acids,  even  to 
sulphuiic. 

Amid  the  many  shifting  corpuscles  and  small  globules  is  a  large  vesicle, 
constant  in  position,  alternately  collapsing  and  dilating,  and  hence  called  the 
contractile  vesicle  (XXII.  4,  5,  6).  This  organ,  which  is  homologous  with 
the  pulsating  sacs  of  Ciliated  Protozoa,  has  not  been  remarked  by  every 
observer,  nor  in  many  of  the  Rhizopoda ;  nevertheless  we  presume  it  to  be 
an  essential  organ,  and  its  existence  general  in  the  class.  Li  Arcella  a  con- 
tractile vesicle  has  been  seen  by  many ;  in  Actinoj)hrys  Sol,  Claparede  has 
satisfactorily  proved  it  a  true  sac,  ha\ing  a  resistant  membranous  wall,  and 
has  counted  as  many  as  ten  such  vesicles  in  Arcella  vulgaris  ;  Auerbach  treats 
of  the  vesicle  as  general  among  Amoehcea ;  on  the  other  hand,  Schultze 
was  imable  to  discover  such  an  organ  among  the  many  Foraminifera  he 
examined. 

I^iJCLEUs. — Another  definite  body  is  mostly  chscoverable  in  Ehizopods,  viz. 
a  nucleus  in  the  form  of  a  more  or  less  rounded  or  oval  body,  more  opaque 
than  the  rest  of  the  contents,  and  consequently  more  solid  in  appearance 
(XXII.  4,  5,  9,  16,  20).  In  Amoeba  and  Arcella,  Ehrenberg  and  Siebold 
admitted  the  existence  of  a  nucleus ;  Schneider  says  that  Amoeha  cliffluens 
and  A.  racliosa  possess  one,  that  a  round  reddish  nucleus  having  a  white 
nucleolus  is  present  in  Difflugia  at  its  hinder  end  (XXI.  19  a,  b,f),  and 
that  probably  aU  the  Rhizopoda  have  such  an  organ.  Kolliker,  to  whose 
hypothesis  of  the  ceU-natiu-e  of  Rhizopods  the  recognition  of  a  nucleus  was 
of  much  importance,  remarks,  "  with  respect  to  the  nucleus,  it  really  appears 
to  be  present  in  some  of  them  (see  Ehrenberg' s  figures)  ;  and  where  it  is  want- 
ing, as  in  Actinophrys,  a  true  nucleus  may  have  existed  at  an  early  period, 
and  be  absent  only  in  the  full-grown  animal,  or,  again,  it  may  be  entirely 
wanting,  and  still  the  animal  be  regarded  as  a  cell." 

Claparede,  on  the  contrary,  denies  a  nucleus  to  the  naked  Rhizopoda,  at 
least  to  Amceha  dijfluens ;  and  hkewise  to  the  testaceous  species,  such  as 
Arcella.  However,  he  admits  that  the  usual  opacity  of  the  shell  is  an 
obstacle  to  an  accurate  determination  of  the  question,  and  remarks,  concern- 
ing the  foregoing  supposition  of  Kolliker,  that  there  is  no  evidence  of  its 
truth,  and  no  foundation  in  fact. 

Schultze  has  encountered  an  undoubted  nucleus  in  nine  different  species  of 
Amoeba,  in  Diffliigia  proteiformis,  D.  acuminata,  and  D.  Helicc,  in  Arcella 
vulgaris  and  several  species  of  Euglypha.  In  Ch^omia  oviformis  a  round, 
clear,  delicate  body  fiUed  with  very  transparent  small  vesicles  may  always 
be  found.  In  old  full-grown  individuals  not  one  but  several  such  bodies  are 
seen  at  the  posterior  part  of  the  animal,  all  of  equal  size  and  of  similar  struc- 
ture (XXI.  12,  13,  14).  In  one  specimen  as  many  as  eighteen  of  these 
nuclei  were  counted.  In  young  small  Gromicf  only  one  nucleus  is  seen; 
in  a  solitary  instance  two  were  found. 

p2 


212  GENERAL  HISTORY  OF  THE  INFUSORIA. 

In  Difflugia ^roteiformis  usually  several  (8  to  12)  nuclei  are  perceptible,  as 
in  Gromia  oviformis,  in  the  j)osterior  portion  of  the  shell. 

The  nuclei  of  freshwater  Ehizopocls  either  appear  to  be  homogeneous  deli- 
cate elastic  globules,  here  and  there  finely  granular,  or  they  resemble  the 
nuclear  body  of  Grojnia  oviformis,  and  consist  of  a  group  of  small  vesicles  or 
globules  enclosed  by  a  common  membrane  (XXI.  14). 

The  single  nucleus  of  young  beings,  Schultze  supposes  to  be  derived  from 
the  parent  animal ;  and  he  fiu-ther  presumes  that,  in  the  coiu'se  of  age  and 
growth,  this  organ  is  capable  of  multiplying  itself,  and  may,  moreover,  serve 
as  a  centre  aroimd  which  the  fine  graniiles  of  the  li^-ing  contents  aggregate, 
and  that,  after  the  formation  of  an  enclosing  membrane,  an  embrj'o  is  generated 
from  it.  On  the  other  hand,  this  careful  obsei'ver  was  not  able  to  discover  a 
nucleus  in  Foramimfera,  and  admits  that  the  above  suppositions  are  highly 
doubtful. 

In  a  large  specimen  of  Gromia  Dujardinii,  Schultze  met  with  certain  en- 
closed bodies,  having  a  firm  shell  and  granular  contents,  and  only  wanting 
a  mouth  to  complete  their  resemblance  to  the  parent  animal  (XXI.  18  a,  b). 
He  also  cites,  as  still  more  questionable  examples  of  a  nucleus,  a  clear  spot  in 
the  fii'st  chamber  of  Rotalia  veneta,  and  in  Textilaria  picta,  a  finely-granular, 
sohd,  and  nucleariform  body  in  each  of  the  two  last  cells  (XXI.  32). 

On  this  point,  the  presence  of  a  nucleus  in  Foraminifera,  we  have  the  state- 
ment of  Ehrenberg,  that  in  each  cell,  except  the  last,  there  is  a  coarsely 
granular  yellowish  brown  mass,  which  represents  an  ovary  in  structiu^e  and 
function.  Unfortunately,  however,  the  Berlin  microscopist  stands  alone,  both 
in  this  observation  and  in  its  pendent  corollary.  Dr.  Carpenter  uses  the 
word  nucleus  to  signify  the  primordial  mass  of  sarcode  seen  in  the  fii'st 
cell,  of  which  all  the  subsequent  chambers  and  their  contents  may  be  deemed 
the  ofishoots. 

Scattered  among  the  amorphous  granules  of  the  sarcode  are,  for  the  most 
part,  numerous  refracting  coipuscles  of  less  size  than  vacuoles,  which  are 
soluble  in  ether,  and  therefore  concluded  to  be  fat-globules  (XXI.  14-16). 
There  are  also  other  molecules  dissolved  by  caustic  potash.  It  is  these 
various  globules  and  granules  that  some  observers  have  esteemed  to  be  ova, 
without,  however,  any  countenance  from  facts  for  the  supposition. 

To  recui'  to  the  naked  Ehizopoda,  Auerbach,  in  the  essay  before  quoted, 
attributes  a  nucleus  to  the  Amoebcva  in  general.  He  remarks  that  the 
sohd-looking  organ,  of  a  dull  aspect  and  commonly  spherical  figui'e,  noted 
by  certain  authors  in  some  Amcebce,  is  rather  the  nucleolus  than  the  nucleus, 
and  that  the  latter  is  perceptible  in  the  form  of  a  hollow  space,  oftentimes 
having  a  ghstening  rosy  hue,  which  surrounds  the  other  like  a  sac  (XXII. 
4,  5,  9, 10, 11).  This  sac  is  sometimes  visible  as  a  dark  areola,  but  at  others 
requires  the  operation  of  chemical  reagents  to  reveal  it,  or  will  manifest  itself 
in  dead  specimens  when  all  the  ordinary  vacuoles  have  disapj)eared.  At 
times,  both  it  and  its  nucleolus  have  a  dumb-bell  figure,  and  thereby  indicate 
the  occurrence  of  the  process  of  self-division.  A  similar  nuclear  sac  is  men- 
tioned by  Schneider. 

As  to  its  chemical  relations,  Auerbach  found  that  both  nucleus  and  nucleolus 
were  readily  soluble  in  alkalies,  and  that  they  became  darker  in  dilute  acetic  or 
sulphuric  acid,  which  also  caused  the  precipitation  of  a  finely-granular  matter 
in  the  vesicular  or  saccular  nucleus.  In  concentrated  acids  they  fii^st  expanded, 
and  were  subsequently  dissolved.  The  generally- assigned  character  of  the 
nucleus,  viz.  that  it  becomes  darker  on  the  addition  of  acetic  acid,  is  true 
only  when  dilute  acid  is  used. 

Auerbach  discovers  a  nucleus  and  nucleolus  in  Arcella,  similar  to  those 


OF  THE  PROTOZOA. RHIZOPODA.  213 

of  Amoebce,  often  displayed  when,  by  a  fracture  of  the  shell,  the  animal  con- 
tents escape.  The  nucleus  has  the  form  of  a  thick-walled  sac,  and  encloses  a 
large  nucleolus.  But  it  is  remarkable  that,  whilst  one  or  at  most  two  nuclei 
only  are  discoYerable  in  Amoebce,  several  such  organs  are  frequently  present 
in  ArceUce,  theu^  number  being  in  direct  proportion  with  the  magnitude  of  the 
animals.  In  large  specimens,  of  i'"  in  diameter,  above  40  such  nuclei  have 
been  encountered. 

Reproduction  of  Rhizopoda. — This  function  is  not  satisfactorily  made  out, 
especially  in  the  case  of  the  Foraminifera  ;  what  is  known  will  best  be  de- 
tailed of  each  family  separately. 

Among  the  Amoebina  self-division  has  been  noticed  by  Ehrenberg  to  occur 
in  t\iQ  Amceba  prince])s;  and  Dujardin  remarks  that  '^  they  may  doubtless 
multiply  by  spontaneous  fission,  or  by  the  thi'o^ving  off  a  lobe  which  imme- 
diately commences  an  independent  existence."  This  separation  of  a  portion 
of  their  substance  is  not  unusual,  as,  when  a  large  variable  process  has  been 
shot  out  far  from  the  chief  mass  and  become  enlarged  at  the  extremity,  the 
expanded  end  retains  its  position,  whilst  the  portion  connecting  it  vdth  the 
body  becomes  finer  and  finer  by  being  withdrawn  into  the  parent  mass,  until 
it  at  last  breaks  across,  lea\'ing  a  detached  piece,  which  immediately  on  its 
own  account  shoots  out  processes,  and  manifests  an  independent  existence. 
This  phenomenon  is  therefore  one  of  simple  detachment,  and  cannot  rightly 
be  called  a  process  of  fission.  Schneider  terms  it  ''  propagation  by  gemma- 
tion," and  supposes  it  attended  by  a  division  of  the  nucleus,  of  which  every 
such  offset,  in  his  opinion,  includes  a  portion.  This  same  observer  fiu-ther 
states  that  Amoeba  has  actually  a  "  state  of  rest "  {i.  e.  an  encysted  condition). 
He  observed  it  fii^st  to  become  round,  and  then  to  form  a  fii^m  membrane  on 
one  side,  whilst  the  other  portion  continued  its  peculiar  character  and  move- 
ments. By  degrees  the  membrane  extended  itself  over  the  whole  body,  the 
moveable  portion  constantly  becoming  smaller,  until  at  last  a  completely- 
closed  cyst  was  produced,  in  the  clear  interior  of  which  a  round  nucleus, 
vdih.  a  reddish  halo,  exactly  like  that  of  Polytoma  and  other  Monaclina, 
might  be  distinctly  observed.  He  adds — "  In  the  nucleus  of  Amoeba  I  have 
often  noticed  on  the  outer  surface  of  the  reddish  halo,  granulations  which 
united  to  form  a  closed  membrane,  whilst  at  other  times  the  nucleus  exactly 
resembled  that  of  Polytoma "  (^.  e.  was  without  an  enclosing  membrane). 
What  is  the  next  phase  of  development  following  this  encysted  stage, 
Schneider  has  nothing  to  show. 

If  Lieberkuhn's  obseiwation  be  correct,  a  most  extraordinary  relation  sub- 
sists between  Amoebce  and  Oregarince,  involving  the  existence  of  the  former 
as  a  distinct  class  of  animated  beings.  This  observer  saw  the  production 
of  Amoebce  from  Navicellce,  the  origin  of  which  from  Gregarince  is  as  good  as 
proved ;  and  also  met  with  such  Amoebce  in  eveiy  transition  to  perfect  Gre- 
garince.  This  fact  is  alluded  to  in  a  paper  by  Kolliker  (J.  M.  S.  i.  p.  212), 
who  behoves  the  AnguiUula-like  animal  noticed  by  Henle,  and  termed  by 
Bract  Filar ia,  to  be  an  Infusorium  aUied  to  Opalina  Proteus,  and  goes  on 
to  say  that  the  transition  of  this  presumed  F'daria  into  a  Gregarina-  and 
finally  into  a  iV«y<ceW«-receptacle  is  nothing  extraordinary.  Auerbach  asserts 
the  encysting  process  to  be  shared  in  by  the  Amcebcea  along  vath.  other 
Infusoria ;  but  he  looks  upon  Schneider's  recorded  instance  as  an  erroneous 
conception  of  a  specimen  clearly  enveloped  by  an  integument. 

Monathalamia  would  seem  capable  of  multiplpng  themselves  Hke  the 
Amoebina,  by  detaching  portions  of  their  substance,  i.  e.  by  a  species  of  gem- 
mation. Peltier  has  described  this  occurrence,  although  Ehrenberg  failed  to 
detect  it. 


214  GE>^ERAL  HISTORY  OF  THE  INFUSORIA. 

lleproduction  by  positive  complete  fission  is  opposed  by  the  existence  of 
the  shell,  which  is  a  product  from  the  siuface  of  the  animals  adapted  to  their 
outline,  and  increasing  only  in  proportion  with  the  augmentation  of  the 
animal  substance. 

The  cohesion  of  two  or  even  more  ArcelUna  by  means  of  their  gelatinous 
substance,  and  often  with  the  near  approximation  of  the  orifices  or  mouths 
of  their  shells,  has  been  remarked  by  many  observers,  who  for  the  most  part 
have  pronoimced  it  a  sort  of  "  conjugation,"  a  true  rejH'oductive  act.  Oohn 
has  indeed  designated  it  "  copulation,"  and  states  it  to  be  a  general  phe- 
nomenon among  Ehizopods.  He  afih^ms  that  he  has  many  times  seen  two 
Difflugice  with  the  mouths  of  their  shells  so  firmly  connected,  that  strong 
shaking  of  the  water  about  them  failed  to  detach  them  ;  and  that  likewise 
one  shell  was  often  empty,  and  the  contents  of  the  two  aggregated  into  a 
globular  mass  in  the  other.  Leclere,  the  fii'st  describer  of  Difflugice,  in  1815, 
noticed  a  like  cohesion  between  two  individuals  of  Difflugia  HeJiv  ;  and  Cohn, 
moreover,  is  able  to  confirm  the  fact  represented  by  Perty  of  the  cohesion  of 
a  brown  and  of  a  pale  shell  together. 

Schneider  has  likewise  noticed  this  adhesion  of  two  animals,  and  thus 
speaks  of  it : — "  Tnie  double  animals  of  Diffiugia  Enchelys  are  frequently 
met  with  (XXI.  19/),  two  bodies  with  membranous  cases  and  nuclei  being 
attached  to  a  common  foot.  The  foot  veiy  often  consists  only  of  a  thin 
thread,  but  in  other  cases  it  exhibits  all  the  forms  which  have  been  described 
as  belonging  to  the  foot  of  the  simple  animal.  Both  bodies  are  well  filled 
vdih.  food.  Three,  four,  or  five  bodies  are  frequently  seen  hanging  together 
in  the  same  manner ;  these,  however,  are  by  no  means  in  the  same  plane, 
but  stand  out  from  the  foot  in  various  directions.  If  these  animals  are  ob- 
tained in  considerable  numbers,  the  formation  of  these  colonies  by  gemmation 
may  easily  be  observed.  The  foot  is  seen  gradually  to  increase  in  size,  and 
acquire  an  oval  form.  A  new  investing  membrane  and  nucleus  are  then 
formed.  The  offset  is  always  equal  to  the  parent-animal  in  size.  Like  the 
foot  of  a  single  animal,  the  common  foot  of  two  or  more  is,  as  might  be 
suj)posed,  still  in  a  condition  to  form  offsets."  This  adhesion  Schneider 
prefers  to  consider  an  act  of  gemmation  rather  than  of  copulation,  and  sup- 
poses its  occiuTence  among  other  Ehizopoda.  He  adds,  ''  with  Perty  and 
Cohn  I  have  also  seen  a  pair  of  the  Arcella  vulgaris  attached  to  one  another 
by  their  openings,  of  which  one  (as  was  obsei'ved  by  those  naturalists)  was 
provided  with  a  white,  the  other  with  a  yellow  shell.  The  white  shell  is 
probably  newly  formed,  and  therefore  indicates  the  young  specimen  produced 
by  gemmation  from  its  companion." 

An  aggregation  of  the  animal  contents  of  a  Monothalamous  shell,  such  as 
Cohn  noticed  in  one  of  the  two  coherent  Difflugice  and  attributed  to  an  act 
of  conjugation,  Schultze  has  seen  in  Phizopods,  quite  independently  of  that 
phenomenon.  In  Lagynis  Bcdtica,  he  states  he  has  frequently  seen  the  con- 
tents collected  into  a  ball,  having  a  clear  speck  in  the  centre,  and  situated  at 
the  posterior  end  of  the  shell,  without  trace  of  extended  fibres ;  and  he  adds, 
"  the  origin  of  this  globular  mass  may  be  followed  in  a  great  number  of 
individuals.  The  posterior  portion  of  the  transparent  body  of  the  actively- 
moving  animal  gradually  becomes  darker,  owing  to  the  advaneuig  develop- 
ment of  numerous  molecular  and  strongly  refracting  particles.  In  the  midst 
of  this  dark  portion  a  clearer  spot  is  always  visible,  although  it  cannot  be 
isolated  or  more  intimately  examined.  By  degrees  the  dark  portion  en- 
croaches upon  the  entire  substance  of  the  body,  and  at  last  fills  up  the  whole 
posterior  portion  of  the  shell,  the  body  of  the  animal  thus  seeming  to  shrivel 
up  into  the  ball-like  mass  described."     This  process,  observed  in  numerous 


OF  THE  PROTOZOA. RHIZOPODA.  215 

individuals  in  different  stages,  Schnltze  never  saw  accompanied  by  a  con- 
nexion between  two  animals ;  and  he  was  not  able  to  discover  what  subsequent 
changes  awaited  the  spherical  body  produced. 

The  phenomenon  just  considered  appears  to  us  to  be  analogous  to  the 
encysting  process  recounted  by  Schneider  in  the  case  of  Amceba,  and  by 
Stein  in  so  many  Cihated  Protozoa. 

Two  other  probable  modes  of  reproduction  are  briefly  noticed  by  Schneider, 
but  requii'e  to  have  theii^  existence  confirmed  by  fiu'ther  observations.  "  I 
have  observed,"  he  says,  "  another  mode  of  propagation  in  our  Difflugice ; 
and  although  my  obseiwations  have  certainly  not  been  frequent,  they  have 
been  sufficiently  satisfactory.  After  I  had  kept  a  great  number  of  these 
creatui'es  for  some  weeks  in  a  clayey  sediment,  the  substance  of  the  body 
in  all  the  individuals  contracted  into  a  ball.  All  foreign  substances  had 
previously  disappeared.  The  ball,  which  had  a  fatty  outline,  then  divided 
into  two  and  four  parts ;  but  the  nucleus  could  not  be  traced  dming  this  pro- 
cess (XXI.  19  d,  e).  This  investing  membrane  fell  to  pieces,  and  the  little 
spheres  Avhich  may  perhaps  be  regarded  as  four  quiescent  spores,  were  no 
more  to  be  seen. 

"  Whether  another  circumstance  observed  by  me  has  any  connexion  ^\dth 
the  reproduction  of  Difflugia  must  be  ascertained  hereafter.  In  all  the 
indi\iduals  of  Difflugia  contained  in  one  vessel,  the  substance  of  the  body 
became  converted  into  granules  closely  packed  together,  the  form  and  the 
investing  membrane  being  retained  (XXI.  19  c).  I  often  saw  these  granules 
in  quick  molecular  movement  in  the  interior  of  a  sac,  which  appeared  to  be 
formed  from  the  outermost  layer  of  the  body,  but  I  watched  in  vain  for  any 
issue  to  this ;  after  moving  about  for  about  half  an  houi%  the  granules  always 
became  quiescent  again." 

A  note  by  Perty  must  not  be  omitted,  although  no  considerable  importance 
can  be  assigned  to  a  solitary  and  ambiguous  observation.  That  naturalist 
tells  us  he  "  once  saw  two  round  motionless  animals  within  an  Arcella  vul- 
garis, each  having  a  much  greater  diameter  than  the  mouth  of  the  sheU  con- 
taining them.  Were  these,"  he  asks,  "  young  beings  to  be  set  free  on  the  death 
of  the  parent  and  the  breaking  up  of  the  shell  ?  "  A  somewhat  similar  fact 
is  recounted  by  Schultze  of  Gromia  Dujardinii,  in  one  large  specimen  of 
which  he  found  several  oval  bodies  enclosed  possessing  a  firm  envelope  and 
granular  contents,  and  representing  in  every  respect  young  Gromia,  except 
in  ha^-ing  no  evident  opening  in  their  shell,  which,  however,  may  possibly  be 
formed  when  set  free  from  the  parent  (XXI.  18). 

That  the  piu-pose  of  the  nuclear  bodies  in  Gromia  oviformis  (see  p.  211)  is 
not  connected  with  the  function,  Schultze  feels  compelled  to  assume,  princi- 
pally from  the  absence  of  such  nuclei  in  Ehizopoda  generally,  and  from  his 
having  failed  to  observe  their  undergoing  those  changes  known  to  occur  in 
true  nuclei  when  the  generation  of  new  individuals  is  in  progress. 

Yoimg  Arcellina,  when  first  recognizable  as  such,  have  the  general  form  of 
older  individuals  ;  but  theii'  shells  and  tissues  are  much  more  transparent,  and 
at  first  colomless  and  without  granules.  But  it  is  very  probable  that  the 
young  of  many  Arcellina,  when  fii^st  thrown  off  from  the  parent,  are  naked — 
destitute  of  shell, — a  \iew  supported  by  an  observation  of  Cohn,  who  records 
having  seen,  amid  the  sUmy  matter  about  living  Difflugice,  a  large  number  of 
pecuHar  animalcules  consisting  of  a  contractile  greyish  or  bro^vn  finely- 
granular  substance,  about  J-th  of  a  line  in  diameter  and  upwards,  of  a  roimd, 
ovoid,  or  angular  outline,  and  having  a  muco-gelatinous  envelope,  through,  but 
chiefly  at  one  end  of  which  several  fibres  were  extended.  At  a  stiU  earlier 
period  these  young  beings  may  therefore  be  presumed  to  have  been  mere 


216  GENERAL  HISTORY  OF  THE  INFUSORIA. 

sarcode-like  particles  or  minute  Amcehce.  If  this  be  so,  some  ground  may  be 
said  to  exist  for  the  hyi^othesis  of  certain  naturalists,  who  esteem  the  ArceUina, 
and  even  the  Foraminifera,  to  be  a  more  advanced  stage  of  existence  of  the 
simple  naked  Amoehina. 

Schneider  hints  at  the  possibility  of  a  still  greater  transformation  in  the 
case  of  his  Diffiugia  Enchelys.  He  writes — "  A  Ehizopod  occurred  in  com- 
pany with  Polytoma  (see  p.  136),  the  description  of  which  Avill  show  how  very 
readily  it  might  be  supposed  to  be  produced  by  a  metamorphosis  of  the  latter 
animal.  Unfortunately  I  cannot  confirm  tliis  supposition,  and  must  confine 
myself  to  recording  the  fact." 

Foraminifera. — It  is  veiy  questionable  whether  the  Many- chambered  Rhi- 
zopods  can  reproduce  themselves  by  off'shoots  after  the  manner  of  Amoehina, 
and  MonoiJialamia ;  and,  in  short,  nothing  certain  is  known  as  yet  of  the 
modes  of  propagation  of  this  family. 

A  group  of  figiu'es  occurs  in  Schultze's  illustrations  of  Polystomella  (XXI. 
39)  which  bear  on  this  point  of  the  possible  production  of  new  beings  by  de- 
tachment of  sarcode  matter.  The  description  of  the  figures  informs  us  that 
some  of  the  sarcode-globules,  separated  from  the  chief  mass  by  pressure,  have 
the  tendency  and  power  to  thi^ow  out  from  themselves  contractile  variable 
processes.  They  exhibit  a  finely-granular  deHcate  semifluid  tissue,  contain- 
ing many  flat  globules  and  large  colom^ed  vesicles.  Other  portions,  pressed 
from  the  general  mass,  are  almost  exclusively  composed  of  colouring-particles, 
derived  from  the  inmost  part  of  the  shell ;  such  become  entirely  free,  or 
othermse  continue  attached  by  a  sort  of  pedicle. 

In  the  following  examination  into  the  modes  of  development  of  Polytlialamia 
we  are  greatly  indebted  to  Schultze's  valuable  monograph.  Dujardin  men- 
tions seeing  in  some  TrvMcatulinoi  the  grouping  of  the  contents  of  the  cham- 
bers into  spherical  masses,  comparable  to  the  green  bodies  in  Zygnema. 
Schultze,  moreover,  encountered,  in  a  deposit  of  living  Foraminifera,  along 
^¥ith  numerous  empty  shells  of  Rotalidce,  several  whoUy  or  partly  filled  with 
black  globules,  the  appearance  of  which  suggested  their  connexion  with  the 
reproductive  process.  Eepeated  observation  showed  that  these  globules 
differed  in  size,  but  mostly  had  the  diameter  of  the  siphon  intervening  be- 
tween the  several  chambers,  or  of  that  of  the  opening  of  the  last  cell.  They 
occupied  either  eveiy  segment  of  the  shell,  when  those  of  the  innermost  were 
smaller  than  those  of  the  outer  compartments,  or  otherwise  they  occiuTcd  in 
only  one  or  two  of  the  ultimate  chambers.  Every  intermediate  condition 
was  met  with  between  these  two  extremes.  The  globules  were  composed  of 
a  collection  of  dark  molecular  corpuscles  not  enclosed  by  a  membrane,  but 
proved  by  pressure  to  be  an  aggregation,  held  together  by  some  sort  of 
delicate  tissue.  They  were  unacted  on  by  sulphuric,  nitric,  and  by  hydro- 
chloric acid,  and  by  boiling  alkalies. 

The  ordinary  animal  substance  coexisted  in  some  of  the  chambers  of  an 
animal  when  others  were  occupied  by  these  black  balls ;  but  in  such  instances 
no  outstretched  fibres  were  seen.  These  structures  must  be  derived  either 
from  without  as  foreign  matters,  or  otherwise  be  the  result  of  a  metamorphosis 
of  the  sarcode  matter.  The  former  supposition  is  discountenanced  by  their 
appearance,  by  their  resistance  to  reagents,  and  their  presence  even  in  the 
inmost  chambers.  On  the  latter  supposition  they  are  either  the  result  of 
decomposition  of  the  substance,  or  they  are  physiological  products,  probably  of 
the  transformation  of  the  entire  body  into  germinal  masses.  The  former  origin 
is  opposed  by  the  direct  observation  that  such  bodies  have  never  been  en- 
countered among  Foraminifera  in  coiu'so  of  breaking  up  or  of  decomposition. 
As  to 'the   second  mode  of  origin,  they  bear  an  analogy  to  the  germinal 


OF  THE  PROTOZOA. EHTZOPODA.  217 

elements  of  Gregarince,  viz.  to  the  Navicelke  developed  from  the  contents 
of  those  animals,  and  to  the  brood  of  germs  developed  out  of  the  contents  of 
an  encysted  Vorticella :  and  it  may  so  happen  with  the  Foraminifera,  that 
their  entire  substance  is  resolved  into  germs  ;  indeed,  a  progressive  formation 
of  such  germs  is  intimated  by  the  circumstance  of  the  ultimate  chamber  being 
the  last  to  become  completely  emptied. 

Although,  therefore,  the  figure  and  size,  the  peculiar  and  successive  empty- 
ing and  distribution,  the  evident  periodical  appearance  in  the  spring,  and  the 
analogy  of  other  Protozoa  speak  for  the  hyjDothesis  of  these  globules  being 
reproductive  germs,  it  must,  on  the  other  hand,  not  be  concealed  that  their 
peculiar  composition  out  of  granules  imperfectly  bound  together  and  enclosed 
by  a  membrane,  and  their  remarkable  resistance  to  the  strongest  acids  and 
alkalies,  are  facts  opposed  to  this  supposition.  Hoping  to  elucidate  theii- 
purpose,  Schultze,  in  some  few  cases,  isolated  those  shells  filled  ^dth  these 
black  balls,  but,  after  keeping  them  several  weeks,  could  discover  no  change 
in  them. 

Ehi-enberg  siu-mised  that  the  Polytlicdamia  propagated  by  ova,  and  thought 
he  perceived  in  them  a  sexual  apparatus.  On  the  surface  of  the  shells  of 
some  samples  of  Geojoonus  {Polystomellci)  and  Nonionina,  from  Cuxhaven  and 
Christiania,  he  discovered  stalked,  yeUow,  membranous  sacs,  which  he  repre- 
sented to  be  ova-sacs.  When  first  thrown  out  they  were  soft  and  small,  but 
soon  swelled  up  and  hardened  in  the  water.  Schultze  also  met  with  many 
specimens  of  Geoponus,  at  Cuxhaven,  having  Cothurnice  afiixed  to  their  shells, 
and  of  a  yellow  colour,  which  he  believes  Ehrenberg  mistook  for  ova- cases. 

Being  so  unsuccessful  by  direct  observation  in  his  attempts  to  detect  the 
method  of  reproduction  among  Foraminifera,  Schultze  endeavoured  by  an  ex- 
amination of  these  beings  in  their  earliest  recognized  form  to  gather  some 
knowledge  of  it.  The  smallest  and  youngest  beings  he  met  with  belonged  to 
the  families  Rotalid(B  and  Miliolida}.  Those  of  the  latter  family  have  a  non- 
porous  shell,  and  a  spherical  figure  exhibiting  the  commencement  of  the  spii^al 
winding  which  eventually  extends  to  several  turns  (XXI.  20  a,  h).  The  sheU- 
contents  are  quite  coloiu'less,  and  present  few  granules.  As  the  spiral  winding 
advances,  the  contents  of  the  first-formed  orbicular  cell  acquire  a  darker  colour 
from  the  appearance  of  fat-drops  and  sharply- defined  proteine  corpuscles ;  and 
the  sheU  simultaneously  assumes  the  characteristic  yellow  colour.  The  differ- 
ence in  size  of  the  primary  cell  in  different  species  is  remarkable.  Still  younger 
forms  of  Eotalidce  occurred  to  him,  0*01  of  a  line  in  diameter,  spherical,  and 
colouiiess,  with  a  delicate  glass-Eke  calcareous  sheU,  through  the  fine  open- 
ings of  which  fibres  protruded.  Others  also,  entii^ely  colourless,  had  a  second 
chamber  superposed  on  the  first,  or  even  three  or  four ;  but  in  the  latter 
instances  the  characteristic  yellow  hue  made  its  appearance,  and  raj^dly  in- 
creased on  fiu-ther  growth  (XXI.  31).  A  striking  variety  was,  moreover, 
remarked  in  the  size  of  the  first  chamber,  even  in  the  same  species ;  the 
dimensions  of  the  second  and  third  cells  were  determined  by  those  of  the 
first.  This  great  variation  in  size  considerably  lessens  the  possibility  of  the 
certain  specific  detennination  of  young  specimens. 

From  these  researches  it  follows,  that  in  MilioUdce  and  Eotalidce,  and  pro- 
bably in  all  other  Pohjtlialamia,  the  first  appearance  of  the  animal  is  in  the 
form  of  a  colourless  spherical  mass,  invested  by  a  delicate  calcareous  waU, — 
the  mass  consisting  of  a  homogeneous,  sparingly-granular  Amoeha-hodcy .  This 
first-formed  cell  has  the  faculty  of  producing  others  like  itself  from  those 
portions  of  its  sarcode  substance. 

Of  the  manner  in  which  successive  chambers  are  formed,  we  learn  from 
Dr.  Carpenter  that  the  addition  of  new  zones  (in  the  Pohjtlialamia)  probably 


218  GENERAL  HISTORY  OF  THE  INFUSORIA. 

takes  place  by  the  extrusion  of  the  sarcode  through  the  marginal  pores,  so 
as  to  form  a  complete  annulus,  thickened  at  intervals  into  segments,  and  nar- 
rowed between  these  into  connecting  stolons,  the  shell  being  probably  pro- 
duced by  the  calcification  of  theii'  outer  portions. 

Since  the  above  account  was  ^viitten,  Schultze  has  produced  a  supple- 
mentaiy  sheet  detailing  further  observations  on  the  development  of  Forami- 
niffera  {Bericht  der  Naturforschenden  GeseUschaft  in  Hcdle,  11th  August, 
1855). 

Having  met  mth  some  large  specimens  of  TrUocidina  ^"'  in  diameter  and 
without  a  tooth  in  the  oral  aperture,  he  kept  them  for  a  length  of  time  under 
observation.  Those  which  remained  adherent  to  the  sides  of  the  glass  vessel  for 
eight  to  foui^teen  days  mostly  became  invested  with  a  brownish  slimy  matter, 
which  more  or  less  completely  obscui-ed  the  view  of  the  external  characters  of  the 
shell.  After  some  more  days  had  elapsed,  the  lens  brought  into  view  a  num- 
ber of  small,  round,  sharply- defined  coi'puscles,  which  loosened  themselves  from 
the  soft  enveloping  mass,  and  gradually  diverged  fi^om  one  another  imtil  some 
forty  were  visible.  On  removing  these,  and  placing  them  imder  the  microscope, 
they  proved  to  be  young  Mdiolidce,  with  their  process  outstretched.  Inter- 
nally, neither  vacuoles,  cells,  nor  contractile  vesicle,  nor  a  nucleus  could  be 
detected. 

The  brief  abstract  of  Dr.  Carpenter's  elaborate  essay  (read  before  the  Royal 
Society,  1855)  furnishes  us  also  with  the  following  memorandum  of  hisAiews 
regarding  the  reproduction  of  Foraminifera,  "svith  especial  reference  to  Orbi- 
tolites.  "  He  is  only  able  to  suggest  that  certain  minute  spherical  masses  of 
sarcode  with  which  some  of  the  cells  are  filled  may  be  gemmides,  and  that 
other  bodies  enclosed  in  firm  envelopes  which  he  has  more  rarely  met  with,  but 
which  seem  to  break  their  way  out  of  the  superficial  ceUsj  may  be  ova."  Mr. 
Jeffrey's  views  {Proceedings  of  JRoyal  Society,  1855)  do  not  quite  coincide. 
Dr.  Carpenter's  ''  idea  of  their  reproduction  by  gemmation,"  he  says,  "  is  also 
probably  correct,  although  I  cannot  agree  with  him  in  considering  the  granules 
which  are  occasionally  found  in  the  ceUs  as  ova.  These  bodies  I  have  fre- 
quently noticed,  especially  in  the  Lagence  ;  but  they  appeared  to  constitute  the 
entire  mass,  and  not  merely  a  part,  of  the  animal.  I  am  inclined  to  think 
they  are  only  desiccated  portions  of  the  animal  separated  from  each  other  in 
consequence  of  the  absence  of  any  muscular  or  nervous  structui'e.  It  may 
also  be  questionable  if  the  term  '  ova '  is  rightly  applicable  to  any  animal 
which  has  no  distinct  organs  of  any  kind.  Possibly  the  fry  may  pass  through 
a  metamorphosis,  as  in  the  case  of  the  Medusce.^' 

Of  the  many  Amcehce  seen  in  company  with  Foraminifera,  the  A.  por recta 
is  particularly  remarkable,  and  might  easily  pass  for  one  of  the  latter  when 
young  and  destitute  of  its  shell ;  for  its  processes  resemble  those  of  Mdiolidce 
and  Rotcdidce  in  delicacy  and  extensibility  and  in  the  cmTent  of  granules 
which  passes  through  them.  This  circumstance  suggests  the  possible  deriva- 
tion of  testaceous  Rhizopoda  from  the  naked  forms  ;  and  if  we  recall  to  mind  the 
black  globules  sui-mised  to  be  germs,  their  j^rimary  transformation  into  Amoehce 
is  imaginable,  and  the  whole  cycle  of  development  of  Foraminifera  becomes 
thereupon  explicable.  *'  However,  I  must,"  says  Schultze,  "  confess  that  this 
change  of  the  black  spheres  into  AmoebcB  is  a  further  argument  against  their 
nature  as  germs,  since  between  these  granular  bodies,  so  imaffected  by  che- 
mical agents,  and  Kmoehce  no  intermediate  link  is  discoverable. 

Of  the  Shells  of  Testaceous  Rhizopoda.  a.  Shells  of  Monothalamia. — 
The  family  ArcelUna  (Ehr.)  corresponds  in  most  points  with  the  section  Mono- 
thalamia of  Schultze.  The  Berlin  Professor,  however,  believed  that  his  family 
Areellina  and  the  Polythalamia  belonged  to  entirely  different  classes  of  ani- 


or  THE  PROTOZOA. RHIZOPODA.  219 

mals,  because,  as  he  supposed,  the  Polyihalamia  are  aggregated  animals  with 
calcareous  shells,  and  the  ArcelUna  solitaiy  animals  with  a  silicious  testa. 
Subsequent  researches  prove,  on  the  contrary',  that  all  these  difiPerential  cha- 
racters are  wanting.  Each  foraminiferous  shell  contains  a  solitary  inmate ; 
and  although,  as  a  rule,  of  a  calcareous  composition,  yet  a  genus,  Polymor- 
phina,  is  pointed  out  by  Schultze,  which,  as  in  the  instance  of  Difflugia,  has 
its  testa  made  up  of  coherent  silicious  particles  (XXI.  38).  Besides  all  this, 
the  shells  of  ArcelUna  are  not  silicious,  but  of  a  chitinous  nature,  and  the 
basement  membrane  in  which  the  earthy  matter  is  deposited  in  Foraminifera 
is  the  same.  These  circumstances,  together  with  the  homology  in  the  animal 
contents  both  of  MonothaJamia  and  of  Polythalamia,  the  absence  of  the  h^-po- 
thetical  polygastric  organization  in  the  former,  and  of  the  imaginary  internal 
structures  in  the  latter,  render  Ehrenberg's  distinction  of  the  two  families  as 
separate  classes  imtenable. 

The  ArcelUna  of  Ehrenberg,  and  the  MonothaJamia  of  Schultze,  do  not  en- 
tirely accord  in  respect  to  the  genera  grouped  under  them.  Ehrenberg  in- 
cluded in  his  family  the  genera  Difflugia,  Arcella,  Cgphidium,  and  SpinlUna, 
The  last-named  genus  departed  much  from  the  others  by  ha\'ing  a  marine 
habitat  and  a  convoluted,  sjnral,  porous  shell, — its  only  real  relationship,  it 
would  seem,  being  comprehended  in  the  one  assigned  feature,  its  sihcious 
lorica.  On  the  other  hand,  Schultze  (see  tabular  ^-iew  of  his  system,  p.  241), 
by  not  emplopng  the  chemical  constitution  of  the  shells  as  a  distinctive  cha- 
racter, includes  among  his  MonotJialamia  calcareous,  membranous  (chitinous), 
and  such  silicious  shells  as  are  exemplified  by  Dijflugia.  The  essential  cha- 
racter employed  is  that  of  the  imilocular  chamber ;  for  the  other  nearly  general 
feature,  ^iz.  the  presence  of  one  considerable  orifice,  is  departed  from  in  the 
instance  of  the  porous  shell  of  OrhuUna. 

The  sheUs  of  Monothalarnia  are  of  a  more  or  less  spherical  figure ;  some- 
times they  are  ovoid  (XXI.  11, 12, 16)  or  pjTiform  (17),  at  others  compressed 
in  one  or  other  direction  (XXI.  8),  and  even  at  times  in  opposite  directions,  so 
that  .-everal  faces  are  produced.  Thus  in  the  genus  Difflugia  the  spherical  out- 
line prevails  (XXI.  10) :  the  sheUs  are  globose,  or  subglobose,  or  elongated  in 
a  pear-shape  (XXI.  17),  or  in  a  club-Hke  (clavate)  manner ;  in  Arcella  they 
are  fi'equently  compressed,  and  assume  a  more  or  less  discoid  figure,  mostly 
convex  above  and  flat  beneath  (7,  8,  9).  In  G-romia,  again,  the  ovoid  or  glo- 
bular shape  is  diversified  by  the  elongation  of  the  portion  about  the  mouth 
of  the  shell  into  a  sort  of  neck  (16).  In  Lagijnis  (Schultze)  this  tapering  of 
the  oral  end  developes  a  retort-shaped  sheU.  In  Squamulina  (Schultze),  again, 
the  testa  resembles  a  plano-convex  lens.  An  exceptional  form  is  described 
by  Ehrenberg,  under  the  name  of  Arcella  disphcera,  as  oblong,  almost  divided 
into  two  by  a  central  constriction.  The  first  impression  would  be  that  the 
supposed  species  was  no  other  than  two  animals  coherent  by  the  mouth  of  the 
shell ;  that  such,  however,  is  not  the  ease  is  indicated  by  the  next  clause  of 
the  description — that  one  segment  is  nearly  occupied  by  the  large  foramen. 
Another  example  of  a  remarkably-formed  shell  is  afforded  by  Cii2:)hidium 
(XXII.  24-27),  which  Ehrenberg  states  to  be  cubical,  with  large  protuber- 
ances, giving  it  in  some  positions  a  four-sided  or  an  irregular  figure.  Again, 
in  the  genus  Spirillina  (Ehr.)  (XL  37)  and  Cornuspira  (Schultze)  (XXI.  2b), 
we  have  examples  of  spii-aUy-roUed  equilateral  shells,  like  those  of  Planorhis. 
In  consistence  the  shells  of  most  ArcelUna  are  firm,  mth  a  degree  of  flexibility 
and  elasticity,  and  are  composed  of  a  dense  membrane  proved  by  its  chemical 
properties  to  be  of  a  chitinous  nature.  This  shell  not  only  resists  the  action 
of  boiling  solutions  of  the  caustic  alkalies  and  of  vinegar,  but  also  concen- 
trated nitric  and  chloric  acids,  and  a  mixture  of  the  two,  also  chromic  acid. 


220  GENEEAL  HISTOKY  OF  THE  INFrSOEIA. 

in  the  solution  of  which  chitine  itself  is  dissolved.  Further  the  shell  is  dis- 
solved in  sulphuric  acid,  and,  unlike  cellulose,  is  not  coloured  blue  by  this  acid. 
Such  are  the  chemical  relations  of  the  testa  of  Gromia  according  to  Schultze ; 
and  such  we  may  presume  with  him  are  those  of  the  freshwater  genera 
ArceUa,  Eugli/jpha,  and  Trinema. 

The  shells  of  Difflugia  are  peculiar  by  being  composed  in  many  species  of 
a  softer  substance,  to  which  various  foreign  particles,  shells  oiDiatomece,  grains 
of  sand  and  the  like,  adhere  and  thereby  furnish  an  accidental  or  supple- 
mentary shield  to  the  animals  (XXI.  17).  The  substance  on  which  those 
accidental  matters  are  affixed  we  may  presume  to  be  chitinous,  but  not  con- 
densed or  hardened  as  in  the  tnie  testaceous  forms.  Schultze  is  disposed  to 
think  that,  besides  merely  agglutinated  sihcious  particles  accidentally,  as  it 
were,  appropriated,  the  investing  tunic  has  actually  the  power  of  secreting 
sihcious  molecules,  represented  by  the  smallest  and  most  intimately  adherent 
granules  of  the  testa.  He  would  also  extend  this  hy[3othesis  to  the  sihcious 
polythalamous  shells,  illustrated  by  Polymorpliina  silicea  (XXI.  38)  and 
another  newly- discovered  species. 

Cohn  apparently  saw  young  Difflugice  in  the  act  of  building  their  sheUs. 
These  yoimg  beings  consisted  of  a  mass  of  sarcode  siuTounded  by  a  muco- 
gelatinous  envelope,  through  which  fibres  were  protruded  in  different  dii*ec- 
tions.  These  processes,  by  retraction,  brought  to  the  surface  of  the  animal 
various  foreign  particles,  which  had  become  affixed  to  them,  and  were  then 
imbedded  in  the  mucous  involucre.  At  length  all  other  pseudopodes,  save 
those  from  one  extremity,  were  permanently  withdrawn,  and  the  exterior  of 
the  animal  was  clothed  with  a  layer  of  silicious  particles,  grains  of  sand,  shells 
of  Cyclotella,  and  of  other  Diatomece,  many  of  them  of  a  blackish  or  brown 
colour'. 

Dr.  Bailey  indicates  an  exceptional  tunic  in  a  Rhizopod,  having  much  of  an 
AmoehaA^kQ  character,  which  he  names  Pamphagus.  It  would  seem  to  be 
enveloped  by  an  integument,  which,  although  resistant,  admits  of  an  immense 
modification  of  figure,  both  from  external  and  internal  pressure,  and  ofi'ers  no 
impediment  to  the  animal  transfixing  itself,  just  as  if  it  were  a  completely 
homogeneous  jelly.  ''These  creatures,"  says  their  discoverer,  "  connect  the 
genus  Amceba  with  Diffugia,  agreeing  with  the  first  in  the  soft  body  without 
shell,  but  difi'ering  in  having  true  feelers  or  rhizopods  confined  to  the  interior 
part  of  the  body."  Just  as  in  Difflugia,  they  are  limited  to  the  region  of 
the  mouth.  From  this  last-named  genus,  "  and  from  the  whole  family  of 
Arcellina,  these  forms  are  distinguishable  by  having  no  lorica  or  shell."  A 
very  similar  tunicated  amoebiform  animal  is  described  by  Dujardin  under  the 
name  Corycia  {A.  S.  N.  1852),  which,  although  clothed  by  a  membranous 
envelope,  can  be  twisted  and  folded  in  every  direction  by  the  movements  and 
contractions  of  the  animal,  and  permits  the  extrusion  of  processes  from  any 
part  of  its  surface.  In  this  respect  it  differs  from  the  Parnpliagus  of  Bailey, 
and  certainly  exemplifies  a  pecuhar  phenomenon,  which,  in  the  case  of  the 
usual  variable  processes  mth  circulating  contents,  would  not  be  conceivable, 
but  become  so  upon  the  explanation  of  Dujardin,  that  they  do  not  contract 
on  adhesion  to  the  surface  on  which  the  animal  moves,  nor  ghde  along  it  in 
the  ordinary  manner,  but  remain  free,  and,  as  we  are  told,  seem  only  to  serve 
to  change  the  centre  of  gravity  of  the  animal.  ^'  It  must,  therefore,"  says  its 
describer,  "  form  a  new  genus  of  Amoehina/^  intermediate  between  the  naked 
Amcebce  and  the  Arcellina ;  and  in  another  direction  indicating  an  aUiance 
Avith  the  Noctilucida. 

With  reference  to  these  pecuhar  beings,  it  is  worth  while  to  bear  in  mind 
the  account  given  by  Cohn  of  the  development  of  young  Difflugice  and  the 


OF  THE  PKOTOZOA. RHIZOPODA.  221 

progressive  formation  of  the  shell.  To  recall  the  particular  points  of  interest, 
in  the  primary  stage  the  Difflugia  was  seen  covered  by  an  integument,  but 
having  processes  extruded  from  various  parts  of  its  surface,  so  far  resembling 
the  Corycia  of  Dujardin, — whilst  in  a  later  stage  all  processes  were  withdi-awn, 
except  Ithose  at  the  one  end  where  the  single  large  orifice  or  mouth  is  placed, 
and  thus  came  to  resemble  the  Pami:>liagus  of  Bailey. 

Calcareous-shelled  Monothalamia  are  represented  by  the  genera  Squamu- 
lina,  Orhulina,  and  Cornusjmri.  Such  shells  are  brittle,  and  in  all  essential 
featiu^es  resemble  those  of  the  next-considered  family,  the  Fo7rim{nifera. 

The  shells  of  Monothalamia  are  generally  coloui'ed.  When  seen,  as  they 
often  may  be,  empty,  they  have  an  orange-yellow,  a  bro^^m,  or  brownish-black 
tint.  This  coloiu'  is  acquii^ed  by  age  ;  the  younger  the  being  the  less  is  it, 
ccetens parihus,  colonized.  In  the  youngest,  as  before  noticed,  the  whole  sub- 
stance and  its  commencing  envelope  are  quite  colourless.  Most  shells  are 
also  translucent  or.  diaphanous  when  empty  ;  but  in  others  the  colour  is  so 
deep,  that,  when  filled,  scarcely  anything  of  the  contained  substance  is  dis- 
cernible through  them.  The  testae  of  Difflugice  are  mostly  opaque.  The  sur- 
face of  the  shells  is  subject  to  numerous  modifications.  Occasionally  it  is 
uniformly  smooth ;  but  many,  which  so  seem  when  occupied  by  the  animal,  are 
found  when  empty  to  be  really  finely  sculptured  (XXI.  11-15). 

Arcella  liyalina  is  represented  by  Ehrenberg  to  have  a  smooth  and  coloui^- 
less  testa ;  A.  vulgaris  and  A.  dentata,  one  superficially  divided  into  facettes ; 
A.  aculeata,  A.  spinosa,  and  A.  caudicola,  a  delicately  hispid  shell.  Where 
the  intersecting  lines  or  ridges  are  not  sufficiently  developed  to  produce  fa- 
cettes, they  give  rise  to  areolae  and  an  areolated  or  reticulated  surface.  The 
surface  is  beset  with  rounded  tubercles  or  eminences  in  Euglypha  tuherculata, 
and  by  spirally-disposed  polygonal  depressions  (alveola)  in  Euglypha  alveo- 
lata  (XXI.  11).  In  Difflugia  acanthophora  (Ehr.)  (XII.  64),  the  surface 
looks  as  if  covered  by  scales  laid  on  in  an  imbricated  manner  and  in.  a  spiral 
direction.  The  same  species  and  Euglypha  alveolata  (XXI.  11)  afford  instances 
of  testae  armed  with  large  and  strong  spines.  This  same  Difflugia  presents 
likewise  an  example  of  the  mouth  of  the  shell  being  strongly  serrated.  Several 
Arcellina  have  small  depressions  or  pits  on  their  sui'face,  which  at  fii^st  sight 
resemble  pores,  e.  g.  Arcella  Ohenii ;  and  both  this  species  and  A.  vulgaris, 
according  to  Perty,  present  very  numerous  striae  diverging  from  the  centre  of 
the  closed  end,  and  concentric  ciixles,  the  outermost  of  which  in  Arcella  Okenii 
are  dentated,  and  follow  the  stellate  expansions  of  the  shell  (XXI.  15). 

Among  Difflugice  the  shell  is  more  often  rough  from  the  adhesion  of  parti- 
cles of  sand  and  of  other  extraneous  substances  (e.  g.  in  D.  iwoteiformis,  J). 
gigantea,  D.  acuminata),  but  in  others  consists  of  a  smooth  membrane,  as  in 
D.  Enchelys,  D.  ohlonga,  and  D.  glohidosa.  Moreover,  Ehrenberg  enumerated 
D.  ciliata,  D.  acanthophora,  and  other  species  as  having  an  areolated  surface, 
D.  ampulla  as  punctated,  D.  dryas  and  D.  reticulata  as  cellular,  D.  Bructerii 
as  rugose,  and  D.  striolata  as  striated.  He  further  states  that  D.  ciliata  has 
a  bristle  or  cii'nis  in  the  centre  of  each  posterior  areola. 

Where  spines  or  other  elevations  of  the  smface — or,  in  fact,  markings  in 
general,  exist — they  may  not  be  imiformly  disposed,  but  be  produced  in  larger 
number  or  of  larger  dimensions  in  some  parts  than  in  others.  Thus  Ekrenberg 
signalizes  an  irregular  disposition  of  the  spines  in  Arcella  aculeata ;  and  not 
uncommonly  such  processes  are  produced  only  from  the  vicinity  of  the  mouth. 

These  examples  will  sufficiently  illustrate  the  diversity  of  sm^face  jDreva- 
lent  among  monolocular  shells  ;  but  these  shells  moreover  differ  as  remark- 
ably among  themselves  in  size,  figure,  and  character  of  the  margin,  and 
likewise  in  the  relative  position  of  their  mouth,  foramen,  or  orifice.     These 


222  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

differences  supply  specific  and  generic  characters  of  much  vahie  by  reason  of 
their  constancy.  Where  the  mouth  has  an  even  uninterrupted  margin,  it  is 
said  to  be  "  entire."  Its  normal  figure  may  be  considered  circular  (XXI.  9). 
However,  in  many  instances  it  is  irregular  (XXI.  15),  or  a  projecting  portion 
encroaches  on  it  (XXI.  6).  In  Dijflugia  depressa  and  I),  gigantea  it  is  uneven  ; 
in  Arcella  lunata,  semilunar ;  in  Difiugia  ampulla,  ovate  ;  in  Splienoderia,  so 
contracted  as  to  be  linear.  Still  more  frequently  the  margin  of  the  aperture  is 
dentated  or  spinous  :  examples  occiu'  in  Difflugia  denticulata,  D.  Jmvigata,  D. 
oligodon,  D,  acantlwpliora  (XII.  64),  and  D.  ciliata,  in  Arcella  dentata  and 
in  EughjpJia.  The  symmetrical  position  of  the  mouth  is  wanting  in  several 
species ;  and  Schlumberger  elevated  this  variation  to  the  importance  of  a  ge- 
neric distinction.  The  obliquity  of  the  aperture — its  position  out  of  the  median 
line — is  noticed  in  Arcella  Americana,  A,  constricta,  A.  ecornis,  and  in  A.  lu- 
nata, also  in  the  genus  Trhiema  (Duj.)  and  in  Cijplioderia  (Schlumberger). 
WTien  the  mouth  appears  formed  by  the  mere  incompleteness  of  the  outline  of 
the  shell,  and  is  without  a  neck  or  deep  margin,  it  is  often  said  to  be  trimcate 
— in  fact,  the  oral  end  of  the  shell  is  truncated  or  abruptly  cut  ofi"  by  the 
orifice. 

The  shells  of  A^xellina  may  be  fractured  by  pressure  when  the  contained 
sarcode  matter  escapes  through  the  fissures,  extending  itself  in  lobe-like  pro- 
longations, which  take  on  the  characters  of  ordinaiy  expansions  (XXI.  7). 
Since  the  opacity  of  the  shell  is  generally  an  impediment  to  the  observation 
of  the  contained  matter,  its  ruptui-e  by  pressiu'e,  or  its  partial  solution  by 
some  reagent,  as  sulphui'ic  acid,  which  acts  upon  the  chitinous  basis,  must 
be  resorted  to  in  order  to  discover  the  nature  of  the  animal  mass  within. 
With  or  without  such  preparation,  it  is  not  unfrequently  seen  that  the  living 
mass  is  not  uniformly  adherent  to  the  inner  surface  of  the  shell,  but  is,  on 
the  contrary,  detached  at  different  parts,  leaving  interspaces  between  it  and 
the  testa,  varying  in  size  and  number.  These  vacuities  may  possibly  arise 
from  the  detachment  of  the  soft  matter  by  reason  of  the  quantity  poinded  out 
fi'om  the  mouth  of  the  shell,  or  other^vise  from  the  formation  of  vacuoles  at 
those  points,  just  as  often  happens  on  the  surface  of  an  Amceha. 

h.  Shells  of  Polythalamia  or  Foraminifera. — These  have  a  great  diver- 
sity in  figure  and  size,  and  are  often  veiy  beautifully  coloured  and  sculptm^ed. 
From  the  resemblance  of  many  to  the  shells  of  Cephalopoda,  especially  to  those 
of  Nautili  (XXI.  28),  they  were  for  a  long  time  ranged  along  -^ith  those 
highly- developed  Mollusca.  The  shells  of  Polythalamia  consist  of  a  greater 
or  less  number,  according  to  age  and  species,  of  communicating  chambers  or 
cells,  aggregated  together  or  superposed  on  one  another  in  different  ways, 
the  mode  of  disposition,  however,  varying  within  certain  limits  even  in  the 
same  species.  Thus  Dr.  Carpenter,  speaking  of  Orhitolites,  says  {Proceedings 
Royal  Society,  1855), — "  Starting  from  the  central  nucleus,  w^hich  consists  of  a 
pear-shaped  mass  of  sarcode  nearly  surrounded  by  a  larger  mass  connected 
with  it  by  a  peduncle,  the  development  may  take  place  either  on  a  simple 
or  upon  a  complex  type.  In  the  former  (which  is  indicated  by  the  circular 
or  oval  fonns  of  the  cells,  which  show  themselves  at  the  sui-face  of  the  disk, 
and  by  the  singleness  of  the  row  of  marginal  pores),  each  zone  consists  of  but 
a  single  layer  of  segments,  connected  together  by  a  single  annular  stolon  of 
sarcode,  and  the  nucleus  is  connected  with  the  first  zone,  and  each  with  that 
which  siuTounds  it,  by  radiating  peduncles  proceeding  from  this  annulus, 
which,  when  issuing  from  the  peripheral  zone,  will  pass  outwards  through  the 
marginal  pores,  probably  in  the  form  of  pseudopodes.  In  the  complex  type, 
on  the  other  hand  (which  is  indicated  by  the  narrow  and  straight- sided  form 
of  the  supei-ficial  cells  and  by  the  multiplication  of  the  horizontal  rows  of 


OF  THE  PROTOZOA. KHIZOPOBA.  223 

marginal  pores),  the  segments  of  the  concentric  zones  are  elongated  into 
vertical  columns,  with  imperfect  constrictions  at  inter^-als ;  instead  of  a  single 
annular  stolon,  there  are  two,  one  at  either  end  of  these  columns,  between 
which,  moreover,  there  are  usually  other  lateral  communications,  whilst  the 
radiating  peduncles,  which  connect  one  zone  with  another,  are  also  multiplied, 
so  as  to  lie  in  several  planes.  Moreover,  between  each  annular  stolon  and 
the  neighbouiing  surface  of  the  disk,  there  is  a  layer  of  superficial  segments 
distinct  from  the  vertical  columns,  but  connected  ^ith  the  annular  stolons  ; 
these  occupy  the  narrow  elongated  cells  just  mentioned,  which  constitute 
two  superficial  layers  in  the  disks  of  this  type,  between  which  is  the  inter- 
mediate layer  occupied  by  the  columnar  segments. 

''  These  two  types  seem  to  be  so  completely  dissimilar,  that  they  could 
scarcely  have  been  supposed  to  belong  to  the  same  species  ;  but  the  examina- 
tion of  a  large  number  of  specimens  shows  that,  although  one  is  often 
developed  to  a  considerable  size  upon  the  simple  type,  whilst  another  com- 
mences even  from  the  centre  upon  the  complex  type  yet  many  individuals, 
which  begin  life  and  form  an  indefinite  number  of  annuli  upon  the  simple  type, 
then  take  on  the  more  complex  mode  of  development." 

Each  cell  is  occupied  by  the  animal  sarcode  substance — sometimes  not 
completely,  so  that  intervals  exist  at  points  between  the  contained  matter 
and  the  enclosing  calcareous  wall,  just  as  in  Monothalamia.  The  first  cell  pro- 
duced, about  which  all  others  are  arranged  and  may  be  considered  ofi'shoots 
or  dependencies,  is  called  the  primary  or  primordial  cell ;  and  in  it  is  con- 
tained the  mass  of  condensed  sarcode  which  Dr.  Carpenter  calls  the  nucleus. 

The  link-like  portions  connecting  one  chamber  with  another  are  called  by 
Schultze  bridges  (Briicken)  or  isthmi,  by  Ehrenberg  siphons,  and  by  Car- 
penter '  stolons.' 

In  chemical  composition  the  shells  of  Poh/thalamia  are  calcareous,  with  the 
exception  of  those  of  Polymorphina  silicea,  which,  like  those  of  many  Diffiugice, 
are  composed  of  small  granules  and  tablets  of  silex.  Schultze  observes  that, 
in  addition  to  this  species,  Spiridina  agglutinans  and  Bignerhia  aggJutmans 
have  their  surface  covered  by  adherent  grains  of  sand,  to  give  it  the  fii'mness 
and  resistance  provided  for  in  other  forms  by  theii'  shells.  The  consequence 
of  their  calcareous  composition  is,  that  the  shells  are  hard,  brittle,  and  opaque, 
and  their  contents  only  visible  so  far  as  protruded  in  the  form  of  processes. 
To  examine,  therefore,  the  animal  matter,  it  is  necessary  to  crush  the  shells, 
or,  better,  to  carefully  remove  some  portions  and  so  expose  the  subjacent  tissue 
to  view ;  or  they  may  be  acted  on  by  dilute  acid,  which  dissolves  out  the 
earthy  matter,  leaving  the  transparent  organic  basis  of  the  testa.  Dujardin 
employed  dilute  acid  mixed  -^ith  alcohol,  which  contracted  and  rendered 
the  sarcode  substance  harder,  and  gave  it  the  appearance,  in  the  many- 
chambered  cells,  of  laminated  or  lobulated  masses  connected  together  by 
thinner  portions. 

When  the  calcareous  earthy  matter  is  dissolved  out  of  the  shells  oiForami- 
nifera,  the  organic  matrix  or  basis  is  left  as  a  transparent  membrane,  retaining 
the  precise  form  and  markings  of  the  complete  shell,  and  perforated  by  the 
characteristic  pores.  Its  chemical  relations  are  those  of  the  membranous  testa 
of  Gromia.  In  thin  shells  the  organic  matter  is  in  relatively  greater  abund- 
ance than  in  the  thick  ones.  Acids  produce  an  active  effeiTescence,  and  so 
prove  the  presence  of  carbonate  of  lime  as  the  principal  mineral  constituent. 
Schultze  has  also  detected  the  presence  of  phosphate  of  lime,  at  least  in  some 
shells,  viz.  in  those  of  Orbiculina  adunca  and  PohjstomeUa  strigilata. 

The  shells  of  Polythalamia  are  commonly  white,  when  viewed  by  reflected 
light,  and  when  emptied  of  their  organic  contents.     \\Tien  the  latter  remain 


224  GENERAL  HISTORY  OF  THE  INFUSORIA. 

a  reddish-  or  yellow-brown  colour  is  ^jrodiiced.  Sufficiently  transparent 
specimens  and  opaque  fragments,  \iewed  by  transmitted  light,  exliibit  either 
a  glass-like  (vitreous)  colourless  appearance,  or  have  a  brown  hue.  Examples 
of  the  latter  condition  are  afforded  by  all  solid  and  not  finely  porous  shells,  by 
MiUolidce,  Ovulince,  and  others.  Moreover,  the  youngest,  thinnest,  and  most 
transparent  shells  are  rendered  visible  by  their  apparent  intense  brown  colour. 
Amongst  porous  species  are  some,  such  as  Orbiculina  and  Sorites,  which  have 
the  brown  colour  only  in  stripes.  Lastly,  Schultze  has  never  met  with  the 
peculiar  yellow,  red,  and  violet  tints  mentioned  by  D'Orbigny  in  some 
RotaUnce,  Roscdince,  and  PlanorhuUnce. 

The  figure  assumed  by  various  PoJytJudamia  is  extremely  varied,  but  is 
nevertheless  reducible  to  certain  types.  We  will  restrict  ourselves  to  a  brief 
description  of  the  primary  forms  established  by  Schultze  ;  these  are  three  in 
number: — 1.  In  which  the  chambers  or  cells  are  superposed  on  one  another 
in  a  straight  series.  2.  In  which  they  are  disposed  in  a  spiral  manner ; 
and,  3.  in  an  iiTegular  fashion. 

The  Nodosaridoi,  which  have  their  cells  placed  one  on  another  in  a  simple 
row,  are  examples  of  the  fii^st  ty^Q  ;  the  Sjnrocidince  of  the  second ;  and  the 
Acervulince  of  the  third  (XXI.  34). 

In  spiral  shells  the  chambers  may  be  rolled  in  one  plane,  so  as  to  form  a 
spnmetrical  shell  with  opposite  sides  alike,  e.  g.  in  Cristellcma,  or,  otherwise, 
in  an  asjTnmetrical  mode,  so  as  to  produce  a  sheU.  like  that  of  the  common 
snail  {Helix),  e.g.  Eotcdia  and  Bosalina  (XXI.  25-28).  This  latter  variety 
may  be  so  modified  by  the  great  elongation  of  the  spiral,  as  to  produce  an 
elongated  conical  outline,  as  in  Uvigerina  and  Bidimina,  when  the  chambers 
above  and  below  each  other  may  present  an  alternate  arrangement.  Other 
varieties  of  the  spiral  are  exemplified  in  Orbicidina,  Alveolina,  and  Nonionina. 
In  many  instances  a  simple  or  regular  spiral  disposition  is  commenced  in  young 
animals,  which  is  departed  from  variously  as  they  attain  the  adult  condition 
and  characters.  Thus  in  Planorhidina  the  regular  s]3ii^al  is  transformed 
eventually  into  a  completely  irregular  form.  Lastly,  the  Acervulince  con- 
sist of  spherical  or  spheroidal  cells  aggregated  into  formless  colonies. 

With  reference  to  the  minute  structm-e  of  the  shell.  Prof.  Williamson 
{Report  of  British  Associcition,  1855,  p.  105)  recognizes  three  principal 
types:  viz. — "  1.  The  hyaline,  generally  consisting  of  a  transparent  vitreous 
carbonate  of  lime,  with,  usually,  numerous  foramina.  2.  PorceUanous,  white, 
opaque,  and  rarely  foraminated.  3.  The  arenaceous,  mainly  consisting  of 
agglomerated  grains  of  sand."  Schultze  makes  two  tj^es :  in  the  one,  the 
shell  is  perforated  by  numerous  fine  pores  or  canals;  in  the  other,  it  is 
homogeneous  and  solid.  The  contents  of  the  second  series  are  brought  into 
relation  with  the  external  world  by  means  of  one  large  opening,  or  by  many 
smaller  ones  collected  in  one  group.  This  division  corresponds,  in  the  main, 
with  that  of  Prof.  Williamson,  except  that  the  German  naturalist  has  omitted 
to  notice,  as  a  thii^d  series,  those  shells  constituted  of  a  membrane  covered  by 
extraneous  particles  of  sand  and  the  Hke. 

The  size  and  distribution  of  the  foramina,  along  with  other  stnictiu'al  pecu- 
liarities, afford  the  best  specific  characters.  To  examine  these  details  the 
shells  must  be  view^ed  by  transmitted  light,  and  by  high  powers.  The  thick- 
waUed  opaque  Foraminifera  are  best  explored,  as  Ehrenberg  first  pointed  out, 
after  being  soaked  in  some  strongly  refracting  varnish,  either  entire  or  when 
cut  into  thin  sections. 

The  dimensions  of  the  canals  vary  in  different  species  from  -0003  of  a  line  (a 
scarcely  measurable  size)  to  -005  of  a  line.  They  are  of  extraordinary  fineness 
in  Polystomella  strigilata,  in  P.  gihha.  and  P.  venusta,  whilst  in   Orhulina 


OF  THE  PROTOZOA. RHIZOPODA.  225 

universa  and  in  Acei'vuUna  globosa  (XXI.  35-37)  they  obtain  their  greatest 
diameter.  In  the  latter,  and  in  Glohiger'ina,  the  canals  dilate  towards  the 
sui'face,  and  are  consequently  fimnel-shaijed  (infimdibidiform).  In  a  few 
instances  two  different  sorts  of  pores  exist,  as  in  Orbulhm  universa  and 
Eosalina  varicnis,  the  finer  kind  being  more  abundant. 

A  peculiar  sort  of  slits  is  characteristic  of  the  genus  Pohjstomella  ;  that  they 
completely  perforate  the  shell  is  shown  by  sections.  They  are  largest  in  P. 
strigilaUi,  and  in  P.  gihha  apj^ear  to  be  only  shallow  excavations. 

Besides  the  openings  named,  the  surface  of  the  shells  often  presents  regularly- 
disposed  eminences  or  elevated  lines.  In  Pohjstomella  strigilata  and  P.  venusta 
(XXI.  28-30)  there  are  hemispherical  or  conical  eminences, perforated  severally 
by  a  fine  opening.  In  Textilaria  picta  elevated  lines  are  arranged  around  the 
widely-separated  pores,  so  as  to  produce  an  elegant  design  (XXI.  2b).  Lastly, 
many  shells  have  a  spinous  or  stellate  appearance,  from  the  prolongation  of  some 
canals  into  long  and  fine  projecting  tubes,  or  from  that  of  the  whole  of  them 
into  thick  processes.  Illustrations  are  afibrded  by  Rosaluia  Imperatoi^ia,  Cal- 
carina,  and  particularly  by  Siderolina  calcitrapoides. 

Carter  has  described  a  greenish,  perishable,  organic  membrane  as  investing 
the  entii^e  suiface  of  the  shells  ^\dth  all  their  irregularities ;  and  d'Ai-chiac 
has  assumed  this  to  be  the  secreting  membrane  of  the  calcareous  matter. 
Schultze,  however,  has  failed  to  detect  such  a  structure  in  every  specimen  he 
has  examined,  whether  in  a  Hving  or  in  a  dried  condition ;  and  he  observes 
that,  even  if  this  membrane  does  exist  in  certain  cases,  there  are  abundant 
facts  to  prove  that  it  is  not  the  seeretiug  organ  of  the  sheU. 

The  foramina  are,  as  a  i-ule,  uniformly  distributed  over  the  shells,  those 
parts  only  being  free  which  are  placed  immediately  above  the  partitions 
between  adjoining  cells.  Exceptions,  however,  occur.  Thus,  in  the  iuequi- 
lateral  Rotalidce  (XXI.  33)  and  their  allies,  the  under  or  umbilical  side  has 
fewer  pores  than  the  upper.  Also,  iu  some  of  the  thick-shelled  species  the 
position  of  the  subjacent  septa  are  not  indicated  by  the  absence  of  pores. 
The  long  winding  canals  pass  in  difterent  directions,  unite,  and  appear  on  the 
surface  in  groups,  producing  a  complex  wavy  pattern  on  the  surface,  as  in 
many  Calcariiue. 

The  partitions  between  the  several  cells  are  perforated  by  oiifices,  which 
differ  in  size,  number,  and  distribution  in  the  several  species.  They  occur  in 
the  septa  as  fine  pores  similar  to  those  of  the  surface,  but  in  less  number. 
Again,  in  species  having  a  single  large  opening  in  their  terminal  chamber, 
there  is  a  similar  one  in  each  partition,  as  in  Nodosarida,  Miliolkla  (XXI.  21, 
22),  Textilaria  (XXI.  36),  Rotalida,  and  in  Nonionina,  Rotidina,  Cristellaria, 
&c.  Among  this  group  the  Comdina  form  an  exception,  in  having  numerous 
foramina  in  the  last  cell  and  in  the  septa  between  the  others.  In  Acervulina, 
again,  the  several  cells  communicate  by  a  single  opening.  In  Peneroplis, 
Cosciiiospira,  and  in  Pohjstomella  the  septa  have  numerous  pores ;  and  the 
foramina  proportionally  increase  in  number  mth  the  increasing  size  of  the 
septa,  i.  e.  from  the  fii\st-  to  the  last-formed  chamber  (XXI.  28-30).  In 
Orhicidina  the  thick  septa  are  penetrated  by  canals. 

Ehrenberg  pointed  out  the  presence,  in  several  species,  of  numerous  per- 
pendicidar  calcareous  columns  interposed  between  the  septa,  which  he  sup- 
posed to  be  hollow  tubes,  opening  up  a  communication  between  the  whole 
series  of  chambers  and  the  exterior.  Both  their  fimction  and  their  tubular 
natui-e  Schultze  disbeheved,  and  asserted  that  Lunulites  (Etw.)  is  not  one  of 
the  Polythalamia,  but  actually  a  colony  of  Bryozoa. 

Mr.  Carter  {A.  N.  H.  1852,  x,  p.  170),  on  the  contrary,  asserts  the  ex- 
istence of  such  tubes  in  the  septa,  in  the  following  passage : — 

Q 


226  GEKEKAL  HISTOET  OF  THE  IN^FUSOEIA. 

"  The  septa  occupy  (in  OjperciiVina  Arahica),  transversely,  about  -^th  of  the 
breadth  of  the  chambers ;  and  each  septum  encloses  within  its  walls  two 
calcareous  tubes  or  vessels,  one  on  each  side,  some  little  distance  below  the 
contiguous  sui'face  of  the  shell  (fig.  7  a,  a);  these  we  shall  call  inter  septal 
vessels.  They  are  irregular  both  in  their  size  and  coiu'se,  though  generally 
about  -j-J^th  of  an  inch  in  diameter,  in  the  last-formed  septa  of  a  shell 
having  the  dimensions  of  the  one  described,  and  diminish  in  calibre  back- 
wards or  towards  the  fii'st-foiTned  whorls.  Each  vessel  commences  in  the 
centre  of  an  intricate  network  of  smaller  ones,  spread  over  its  own  side 
of  the  margin  of  the  preceding  whorl,  and  under  the  layers  of  the  shell ; 
these  networks,  which  are  joined  together,  we  shall  call  the  marginal  plexus. 
In  its  course  each  interseptal  vessel  gives  off  two  sets  of  ramusculi,  and  the 
marginal  plexus  one  set.  Of  those  coming  from  the  interseptal  vessel,  one 
set  terminates  on  the  siuface  of  the  shell,  particularly  about  the  borders 
of  the  septum ;  the  other  goes  into  the  walls  of  the  shell,  and  through 
the  septum,  to  open  probably  on  the  inner  surface  of  the  chamber,  while 
the  set  from  the  marginal  plexus  opens  on  the  margin.  As  this  vascular 
system  appears  to  extend  throughout  every  part  of  the  shell,  and  must  be 
for  the  circulation  of  some  fluids  we  will  call  it  the  interseptal  circulation.''^ 

Prof.  Wilhamson  has  likemse  described  a  series  of  intraseptal  canals  in 
Faujasina,  and  illustrated  their  arrangement  by  engravings.  We  have  not 
space  to  give  the  details,  but  can  quote  only  the  general  results : — "  The  intra- 
sejDtal  spaces  are  vertical,  and  give  off  true  divergent  cylindrical  canals  from 
their  external  margins,  penetrating  the  thick  parietes  of  the  shell.  These 
spaces  extend  from  the  top  to  the  bottom  of  each  septum,  and  only  assume 
the  form  of  canals  when  they  approach  the  peripheral  shell-walls.  The  con- 
necting branches  which  unite  the  S2)aces  of  different  convolutions  are  also 
tubular.  In  no  instance  do  these  spaces  or  their  divergent  canals  commimi- 
cate  with  the  interior  of  the  segments  (chambers)  ;  for  the  only  dii^ect  com- 
mimications  between  the  two  parts  of  the  organism  are  thi'ough  the  pseudo- 
podian  foramina,  many  of  which  open  into  the  tubular  portions  of  these 
passages  ;  but  never,  so  far  as  I  have  observed,  into  the  intraseptal  spaces." 
Again,  "  the  caidties  in  the  translucent  shell  are  thickly  lined  mth  a  dark 
ohve-brown  substance,  which,  if  it  be  the  desiccated  soft  animal,  proves  that 
in  this  species  the  gelatinous  tissue  has  not  only  filled  the  true  chambers,  but 
has  also  occupied  the  intraseptal  canals  and  passages.  If  this  be  so,  it  is 
curious  that  the  only  medium  of  commimication  betA^'ecn  the  soft  tissues  in- 
habiting the  spiral  segments  of  the  shell  and  those  occupying  the  intraseptal 
and  central  passages,  should  be  the  minute  pseudopodian  foramina ....  It  is, 
however,  ob\'ious  that  this  organism  supports  the  conclusion  at  which  I  arrived 
in  a  previous  memoir,  viz.  that  the  soft  animal  had  the  power  of  extending 
itself  externally  far  beyond  the  limits  of  any  individual  segment,  and  would 
thus  be  able  to  secrete  calcareous  matter  in  other  situations  than  the  mere 
parietes  of  its  o^tl  segment.  It  is  only  in  this  way  that  we  can  explain  the 
production  of  the  dome-like  covering  which  encloses  the  central  umbihcal 
cavities  and  their  ramifying  canals.  But  if  it  should  be  ultimately  proved 
that  the  soft  tissues  have  occupied  all  these  irregular  cavities,  we  shall  then 
have  a  form  of  organization  which,  from  its  great  variability  of  contour,  ^vill 
approach  much  more  closely  to  the  calcareous  sponges  than  any  hitherto  de- 
scribed." 

Schultze  says  that  the  species  referred  to  by  the  two  observers  just  quoted 
have  not  come  in  his  way,  but  that  in  none  of  the  genera  he  has  examined 
has  he  met  with  a  similar  structure.  He  has  been  equally  unsuccessful  in 
finding  the  interseptal  spaces  noticed  by  Carpenter  in  Nummulites  ;  and  in 


OF  THE  PROTOZOA. EHIZOPODA.  227 

no  genus  he  has  examined,  has  he  been  able  to  discover  its  shell  to  be  com- 
posed of  calcareous  spicula,  such  as  Carter  represents  in  OpercuUna  Arahicay 
and  refers  to  as  indicative  of  the  intimate  affijiity  between  Foraminife^xi  and 
sponges,  in  the  ensuing  j^aragraph  {A.  N.  H.  x.  1852,  p.  173) : — ''  It  must 
be  now  generally  allowed  that  the  Rhizopodous  nature  of  Foraminifera  is 
identical  with  that  of  the  Amoeba  or  Proteus,  and  through  the  latter  with  the 
Sponge-cell ;  and  in  addition  to  this,  we  have  the  former,  at  least  the  genus 
Operculina,  stiU  more  nearly  aUjing  Foraminifera  to  the  Sponges,  by  possess- 
ing a  spicula  structui^e,  if  not  a  circulating  system  also,  like  that  of 
SjDonges." 

The  calcareous  sheU  of  Rhizopoda  is  lined  (XXI.  16)  within  by  a  delicate 
organic  homogeneous  membrane,  with  a  sharp  outline,  and  of  a  more  or  less 
deep-broAvn  colour.  It  is  in  immediate  contact  with  the  animal,  and  closely 
apphed  to  the  shell,  and  has  the  same  perforations  (XXI.  24).  It  penetrates 
from  one  chamber  to  the  next  through  the  intermediate  pores  and  canals. 
Duiing  life  it  is,  in  the  last-formed  chambers,  colourless.  It  is  not  equally 
visible  in  all  species.  By  the  addition  of  dilute  acid  to  Botalia,  Rosalina,  and 
Textilaria,  it  is  readily  brought  into  \dew  ;  but  in  Miliolida  this  is  difficult, 
o^ving  to  its  dehcacy  and  want  of  colour.  In  the  first-formed  (primordial) 
chamber,  occupied  by  colourless  substance,  it  would  seem  to  be  absent.  In 
its  chemical  relations  it  resembles  the  chitinous  shell  of  Gromia,  and  is  so 
very  slowly  destroyed  by  decomposition,  that  it  may  be  demonstrated  in 
empty  shells  found  amidst  the  sand  at  the  sea- side,  and,  according  to  d'Archiac 
and  Jules  Haime,  even  in  fossil  specimens. 

Dimensions  and  Conditions  of  Life  of  Rhizopoda. — The  size  of  the  Rhi- 
zopoda is  very  varied,  even  among  members  of  the  same  genus.  Ehi-enberg 
describes  Amoehoi  fi'om  ^  l^^th  and  i^J-jjth  to  y^th  of  an  inch  ;  Difflugice  from 
g-JfTo-tli?  and  YY,Vuth  to  T^th,  and  ArceUce  from  yy-o-th  to  ^xo^^  ^^  ^^  inch. 
Between  individuals  even  of  the  same  species,  he  represents  a  diversity  of 
size  of  nearly  equal  extent.  Schultze  states  the  diameter  of  the  shells  of 
Gromia  oviformis,  and  of  G.  Diijardinii,  to  be  -gyth  of  an  inch,  whilst  that  of 
Lagynis  is  only  tt-J  ,jth  in  length.  Dujardin  remarks  that  the  largest  fresh- 
water Rhizopoda  attain  a  diameter  of  -^2^(^,  whilst  the  marine  Foraminifera 
are  for  the  most  part  visible  to  the  naked  eye,  and  have  a  length  of  from  ^^^th 
to  -i-th  of  an  inch.  The  Xautiloid  shells  of  PolystomeUa  have  a  diameter  of 
gL-th  to  2yth  of  an  inch,  and  the  ii'regularly- chambered  AcervuUnce  a  length 
of  fi'om  Jjtt^  to  -1th  of  an  inch.  Among  fossil  Foraminifera  larger  sizes 
prevail :  thus.  Sir  E.  Belcher  brought  one  species  from  Borneo  measuring  more 
than  2  inches  in  diameter ;  and  many  Nummulites  are  found  an  inch  and 
upwards  in  diameter. 

Mr.  Jeffreys  gives  the  following  account  of  the  habits  of  Foraminifera 
(Proc.  Roijal  Soc.  1855)  : — "■  Most  are  free,  or  only  adhere  by  theii'  pseudo- 
podes  to  foreign  substances.  Such  are  the  Lagena  of  Walker,  Nodosaria,  Vor- 
ticiaJis,  and  Textidaria,  and  the  Miliola  of  Lamarc.  The  last  genus  has  some, 
although  a  very  limited,  power  of  locomotion,  which  is  effected  by  exserting  its 
pseudopodes  to  their  fiiU  length,  attaching  itself  by  them  to  a  piece  of  seaweed, 
and  then  contracting  them  like  india-rubber,  so  as  to  draw  the  shell  along  with 
them.  Some  of  the  acephalous  mollusks  do  the  same  by  means  of  theii'  bj^ssus. 
This  mode  of  progression  is,  however,  exceedingly  slow ;  and  I  have  never 
seen,  in  the  course  of  24  hoiu-s,  a  longer  joui^ney  than  a  quarter  of  an  inch 
accomplished  by  a  Miliola.  .  .  .  Some  are  fixed  or  sessile,  but  not  cemented  at 
their  base  like  the  testaceous  Annelids.  The  only  mode  of  attachment  appears 
to  be  a  thin  film  of  sarcode.  The  Lohatida  of  Fleming,  and  the  Rosalia  and 
Planorhidina  (D'Orb.)  belong  to  this  division.     Dr.  Cai^Denter  considers  the 

q2 


228  GENERAL  HISTOEY  OF  THE  rNTFSOIlIA. 

Foraminifera  to  be  phytophagous,  in  consequence  of  his  having  detected  in 
some  specimens  fragments  of  Diatomaceae,  and  other  simple  forms  of  vegetable 
life.  But  as  I  have  di^edged  them  ahve  at  a  depth  of  108  fathoms  (which  is 
far  beyond  the  Laminarian  zone),  and  they  are  extremely  abundant  at  from 
40  to  70  fathoms,  ten  miles  fi^om  land  and  beyond  the  range  of  any  seaweed, 
it  may  be  assumed,  T^dthout  much  difficulty,  that  many,  if  not  most  of  them, 
are  zooj)hagous,  and  prey  on  microscopic  animals  perhaps  of  even  simpler  form 
and  structure  than  themselves.  They  are  in  their  turn  the  food  of  Mollusca, 
and  appear  to  be  especially  relished  by  Dentalium  entale.^'  The  assumption 
that,  because  the  Laminarian  zone  ceases  at  a  much  less  depth  than  that  at 
which  Foraminifera  occur,  therefore  no  Diatomeae  are  found,  is  quite  gra- 
tuitous, and  opposed  to  observation.  The  notion  also  that  animal  life  fur- 
nishes nutriment  to  Foraminifera  at  depths  where  vegetable  existence,  and 
where  the  doubtful  Diatomeae  cannot  be  sustained,  is  opposed  to  all  proba- 
bihty. 

Of  the  rate  of  growth  and  of  the  duration  of  Ehizopoda  we  have  few  re- 
corded observations  :  we  must,  however,  suppose  them  regulated  by  external 
cii'cumstances,  such  as  abundance  of  food,  moderate  temperature,  and  the  like. 
Schultze  observed  of  'Foraminifera  living  in  a  small  quantity  of  sea- water,  so 
to  speak,  in  captivity,  that  they  grew  exceedingly  slowly.  In  only  one  Po- 
ly stomeila  out  of  many,  kept  under  observation  for  several  months,  did  he  ob- 
serve the  production  of  a  new  chamber.  Rotalice,  however,  were  more  fre- 
quently seen  in  process  of  growth,  the  walls  of  the  new-formed  segments 
being  extremely  dehcate  and  deficient  of  calcareous  matter.  Some  very  young 
specimens  of  MiJiola  ohesa  were  found  to  produce  two  new  chambers,  after  the 
completion  of  the  primary  one,  in  the  com^se  of  four  weeks. 

From  this  fact  of  their  very  gradual  growth,  says  Schultze,  we  may  con- 
clude that  a  year  or  more  may  elapse  before  the  construction  of  a  many- 
chambered  shell  is  completed.  This  natui'alist  has,  indeed,  kept  the  same 
specimens  of  PohjstomeUa  and  of  Rotalida  in  capti\dty  for  nine  months  ;  and 
theii'  persistence  for  a  much  longer  period  is  highly  probable.  If,  he  adds, 
the  production  of  germs  put  a  termination  to  life,  then  this  phenomenon 
entails  a  fixed  limit  to  its  duration.  Dujardin,  again,  found  Arcellce  alive  after 
two  years,  in  a  vessel  in  which  he  had  preserved  them. 

The  testaceous  Ehizopoda  possess  the  power  of  repaii'ing  the  efi'ects  of  me- 
chanical injimes  to  their  shells.  This  has  been  proved  by  Schultze  in  the 
case  of  the  Polythalamia  ;  and  we  may  conclude  the  same  faculty  is  possessed 
by  the  Monotlialamia.  He  has  seen  almost  one-half  of  the  shell  of  Pohjsto- 
mella  strir/ilata,  which  had  been  broken  away,  repaired  by  a  new  calcareous 
wall  resembling  the  normal  one  both  in  its  pores,  eminences,  and  markings. 
He  also  frequently  noticed  in  this  same  species  irregularities  in  the  conforma- 
tion of  the  shell,  which  he  attributed  to  damages  previously  inflicted ;  and 
experiment  showed  him  that,  even  on  the  same  day  that  a  considerable  portion 
was  removed,  the  animal  set  vigorously  to  work  to  rei)lace  the  lost  sheU,  and 
protruded  its  processes  just  as  before. 

Occasionally  the  destruction  of  a  portion  of  the  shell  gives  rise  to  monstrous 
(abnormal)  forms.  Thus  Schultze  noticed  a  double  PolystomeUa  strigilata, 
and  Eeuss  a  monstrous  Nodosaria  anmdata,  which  he  called  N.  dichotoma  ;  and 
Dr.  Carpenter  has  foimd  several  "  monstrosities  of  Orhitolites  resulting  from  an 
unusual  outgrowth  of  the  central  nucleus." 

The  Ehizopoda  can,  doubtless,  maintain  life  under  very  prejudicial  condi- 
tions. The  power  possessed  by  the  sarcode  substance,  of  sustaining  existence 
when  even  the  greater  part  is  torn  away,  and  the  capability  of  repair  mani- 
fested by  the  testaceous  species,  are  facts  indicative  of  their  tenacity  of  fife. 


OF  THE  PEOTOZOA. EHIZOPODA. 

Another  proof  is  found  in  the  capacity  of  Foraminifera  to  exist  for  weeks  and 
months  in  the  same  water.  Schiiltze  states  that  he  has  found  them  lying 
motionless,  with  retracted  processes,  at  the  bottom  of  a  vessel  of  putrid  water, 
in  which  they  had  been  kept  a  long  time,  and  that  when  this  water  has  been 
changed,  or  its  foul  odour  removed  by  an  acid,  they  have  recommenced  to 
move  about,  and  to  thrust  out  their  fibres.  In  a  small  glass  containing  mud 
from  the  lagoons  of  Yenice,  and  in  which  life  appeared  extinct,  he  found  Ro- 
talidte  and  Miliolidce  creeping  on  the  sides,  and  in  great  numbers  in  the  sedi- 
ment at  the  bottom.  Some  still  more  recent  experiments  have  convinced  this 
eminent  naturalist  that  fresh  water  is  not  very  detrimental  to  them,  but  that, 
on  the  contraiy,  they  may  be  kept  ahve  in  it  for  a  considerable  time.  He 
found  at  the  same  time  that  some  dried  Polytlialamia  from  mud  obtained  at 
Muggia,  and  let  dry  for  five  weeks,  continued  motionless  after  six  weeks' 
immersion  in  sea- water. 

Haeitats  and  Distribution  of  Ehizopoda. — Fossil  Poe:ms. — The  Amoehce 
are  met  mth  particularly  in  water  containing  much  organic  debris,  provided 
that  decomposition  is  not  proceeding.  They  are  common  inhabitants  of  infu- 
sions, and  of  stagnant  water,  and  are  foimd  adherent  to  foreign  bodies,  to  plants, 
Confei^'ae,  and  the  like.  Although  unable  to  s^Wm,  they  are  fi^equently  floated 
to  the  surface  on  the  matters  to  which  they  stick,  such  as  dead  leaves.  Algae, 
or  stalks  of  plants.  They  occur  both  in  fresh-  and  in  sea-water,  but  are  much 
more  commonly  seen  in  the  fonner. 

The  Moaothalamia,  with  reference  to  their  habitats,  form  two  groups,— 
one  marine,  the  other  freshwater.  Arcella,  Diffiugia,  and  Euglypha  are 
essential  freshwater  genera,  whilst  Spirillina  (Ehr.),  Gromia,  Lagynis  (Sch.), 
and  SquameUa  (Sch.)  are  marine.  They  are  not  met  with  in  infusions  arti- 
ficially prepared  although  common  in  stagnant  water  holding  organic  matters 
in  suspension,  and  found  crawling  on  these  or  on  the  sides  of  the  vessel 
containing  the  water. 

PoJythalamia  are  all  marine.  Their  abimdance  and  extent  of  distribution 
are  surprising ;  this  is  true  of  them  both  in  the  living  and  in  the  dead  or 
fossil  condition.  Schultze  states  that  on  the  northern  level  shore  of  the  har- 
bour' of  Ancona,  the  shells  of  the  Foraminifera  cover  the  suiface  here  and 
there  Kke  a  fine  sand,  and  are  discovered  in  many  places  in  smaller  numbei^ 
at  a  depth  of  20  feet.  When  this  sand  was  placed  in  water  in  a  glass  jar,  no 
specimens  were  found  to  crawl  up  the  sides ;  and  observation  showed  that  few 
among  them  retained  any  organic  contents.  Prom  a  small  rocky  islet  in  the 
harboui'  he  scraped  into  a  fine  net  the  slimy  mud,  and  then  separated  the 
lighter  suspended  particles  from  the  mixture  of  animal  and  vegetable  matter, 
and  placed  them  in  another  glass.  On  examining,  a  few  hours  later,  the  fine 
sand  so  separated,  he  found  it  almost  entirely  composed  of  Polytlialamia,  filled 
with  theii'  organic  substance  and  alive,  many  of  them  having  crawled  up  the 
sides  of  the  vessel.  His  experiments  at  Yenice  were  entirely  correspondent ;  no 
living  beings  were  found  in  the  sand  from  the  shore,  but  countless  specimens 
in  the  debris  about  the  Alga3  in  the  lagoons.  Once,  however,  at  Cuxhaven, 
on  the  Elbe,  he  met  with  living  Foraminiftra  in  the  sand. 

Dujardin  also  says  of  the  Polytlialamia,  that,  from  being  imable  to  SAvim, 
they  are  only  to  be  found  attached  to  the  surface  of  bodies  on  which  they 
crawl,  such  as  aquatic  plants,  or,  otherwise,  lying  amidst  the  debris  covering 
the  base  of  such  plants,  or  in  the  hollows  between  the  asperities  of  the  shells 
of  marine  Mollusca.  Sponges,  again,  form  a  convenient  habitat  for  li^dng 
Polytlialamia,  ha\ing  theii'  pores  at  times  pretty  well  filled  with  them ;  in 
the  same  way  Corals  and  Corallines  are  fix-quently  beset  with  them.  This 
necessity  of  attachment  cannot  universally  prevail,  since  the  Foraminifera  are 


230  GENERAL  HISTOEY  OF  THE  INFUSOEIA. 

SO  often  found  scattered  over  the  bed  of  the  ocean,  as  well  in  the  li\dng  as  in 
the  dead  state,  without  any  Algae  near,  whereto  they  can  adhere. 

The  extraordinary  abundance  of  Foraminifcrous  shells  in  the  sand  of  some 
sea-shores  has  been  long  observed.  Plancus,  in  1739,  counted,  with  the  aid 
of  a  low  magnifying  power,  6000  individuals  in  an  ounce  of  sand  from  Eimini, 
on  the  Adriatic;  and  D'Orbigny  states  that  3,840,000  exist  in  an  equal 
quantity  of  sand  from  the  Antilles.  Schultze  also  counted  500  shells  of  lihi- 
zopoda  in  ^th  of  a  grain  of  sand  collected  from  the  Mole  of  Gaeta,  which  had 
pre\'iously  been  passed  through  a  sieve  and  separated  fi'om  all  particles  above 
yi^th  of  an  inch  in  size. 

Ehrenberg  describes  finding  Pohjthdlamia  both  on  the  surface  of  the  sea 
and  also  at  the  bottom,  even  at  a  depth  of  12,000  feet.  From  these  great 
depths  they  are  procured  by  soundings  ;  the  lead,  after  being  coated  mth 
grease  at  the  bottom,  brings  up  attached  to  it  the  small  particles  of  sand  and 
other  matters  mth  which  it  comes  into  contact  at  the  sea-bottom.  Numerous 
such  soimdings  were  taken  by  Sir  J.  Iloss  in  his  Antarctic  expedition,  and 
have  been  practised  by  others  in  different  regions.  Dr.  Bailey  records  the 
results  of  a  series  of  deep  soimdings  made  in  the  Atlantic,  over  a  considerable 
geograjihical  area,  from  latitude  42°  4'  to  lat.  54°  1 7',  and  depths  varying 
from  1080  to  2000  fathoms.  "  None  of  the  soundings,"  ho  states,  "  contain  a 
particle  of  gravel,  sand,  or  other  recognized  unorganized  mineral  matter. 
They  all  agree  in  being  almost  entii'ely  made  up  of  the  shells  of  Foraminifera. 
....  But  neither  the  smface-water  nor  that  of  any  depth  . .  .  collected  close 
to  the  places  where  the  soundings  were  made,  contained  a  trace  of  any  hard- 
shelled  animalcules."  Schultze  is  unable  to  receive  Ehrenberg's  statement  of 
finding  shells  floating  on  the  sm^face  of  the  sea,  seeing  that  they  naturally 
sink  in  water.  Still  he  admits  that  in  shallow  water  they  may  be  suspended 
by  the  tossing  of  the  waves,  and  that  they  may  float  on  the  surface  attached  to 
sea- weed  torn  from  the  bottom,  or  to  other  floating  substances.  He  likewise, 
and,  we  think  (judging  from  the  laws  of  distribution  of  organic  life  at  different 
depths  as  pointed  out  by  the  late  Prof.  Edward  Forbes),  very  justly,  demurs 
to  Ehrenberg's  conclusion,  that  the  Polythalamian  shells  fished  up  fi'om  the 
great  depths  cited,  and  others  approaching  them,  lived  at  those  depths,  and 
had  become  empty  by  speedy  decomposition  of  their  animal  contents.  At 
depths  far  less  considerable,  we  believe  all  organic  life  ceases,  and  should 
consider  the  Foraminifcrous  shells  there  found  to  have  been  drifted  from  other 
less  profound  places  by  currents  in  the  ocean.  Prof.  Bailey  also  started  the 
question,  whether  the  Foraminifera  found  at  the  bottom  of  the  sea  actually 
lived  there,  or  were  borne  there  by  submarine  currents,  but  admitted  that 
these  and  other  like  questions  could  not  be  at  j^resent  decided.  What,  however, 
is  veiy  remarkable,  is  that  the  species  "  whose  shells  now  compose  the  bottom 
of  the  Atlantic  Ocean  have  not  been  found  li^dng  in  the  surface  waters,  nor  in 
shallow  waters  along  the  shore.  It  is  but  fair,  also,  to  state  that  Mr.  Jeftreys 
has  dredged  living  Polytlialamia  from  a  dei)th  of  108  fathoms  (648  feet). 
So  far  as  Schultze' s  researches  go,  they  prove  a  very  Hmited  geographical 
distribution  of  some  species  of  PolythaJamia.  Thus,  he  has  never  foimd  the 
Rotalia  Veneta  elsewhere  than  at  Venice  and  Muggia,  near  Trieste,  whilst 
the  Polystomella  strigilata,  of  Ancona,  is  altogether  absent  at  Venice  and 
Trieste.  Nodosaridoi,  which  are  common  enough  at  Rimini,  are  sought  in 
vain  at  Ancona,  close  by,  whilst  Rotalia  Beccarii  occurs  at  both  those  places. 
So  Peneroplis  ])lanata  is  found  in  the  sand  on  the  Istrian  coast,  from  Citta 
Nuova  to  Pola,  but  is  absent  at  Trieste,  Venice,  and  Ancona.  Similar  illus- 
trations might,  says  Schultze,  be  multiplied,  to  show  the  considerable  diversity 
of  local  fauna. 


OF  THE  PROTOZOA. RHIZOPODA.  231 

A  limited  distribution,  both  in  reference  to  place  and  to  the  conditions  of 
existence,  has  been  determined  by  Ehrenberg  and  other  observers  of  the  Poly- 
thalamia,  and  also  employed  by  geologists  in  fixing  the  period  of  the  deposi- 
tion of  certain  strata,  and  the  circumstances  under  which  it  has  occurred. 
Thus  Bailey  records  of  the  Atlantic  soundings,  that  they  "  contain  no  species 
belonging  to  the  group  AgatMstegia  (D'Orbigny),  a  group  wliich  appears  to 
be  confined  to  shallow  waters,  and  which  in  the  fossil  state  first  appears  in 
the  tertiary,  where  it  abounds."  Again,  they  "  agree  with  the  deep  soundings 
off  the  coast  of  the  United  States,  in  the  presence  and  predominance  of  species 
of  the  genus  Glohigerina,  and  in  the  presence  of  the  cosmopolite  species  Orbu- 
lina  universa  (D'Orb.) ;  but  they  contain  no  traces  of  the  Margimdina  Bachii, 
Textilaria  Atlantlca,  and  other  sj)ecies  characteristic  of  the  soundings  of  the 
Western  Atlantic.  In  the  vast  amount  of  pelagic  Foraminifera,  and  in  the 
entire  absence  of  sand,  these  soundings  strikingly  resemble  the  chalk  of 
England,  as  well  as  the  calcareous  marls  of  the  Upper  Missoiui ;  and  this 
would  seem  to  indicate  that  these  also  were  deep-sea  deposits.  The  cretaceous 
deposits  of  New  Jersey  present  no  resemblance  to  these  soundings,  and  are 
doubtless  littoral,  as  stated  by  Prof.  H.  D.  Rogers." 

A  fijj:ed  geographical  distribution  is  also  implied  by  the  division  made  by 
D'Orbigny  of  the  sj^ecies  he  observed, — viz.  into  575  peculiar  to  the  torrid 
zone,  350  to  the  temperate,  and  75  species  to  the  frigid  zone.  Moreover,  Dr. 
Carpenter  stated  (in  the  Annual  Addi'ess  at  the  Microscop.  Soc.  1855)  that 
he  and  Prof.  Williamson  find  "  that  there  are  certain  species  whose  range  of 
distribution  is  limited,  and  whose  form  is  remarkably  constant,  but  that,  in 
by  far  the  greater  number  of  cases,  the  species  of  Foraminifera  are  distributed 
over  very  wide  geographical  areas,  and  have  also  an  extensive  geological 
range."  Mr.  Jeffreys  remarks  that,  in  his  opinion,  <'  the  geographical  range, 
or  distribution  of  species,  is  regulated  by  the  same  laws  as  in  the  Mollusks  and 
other  marine  animals.  I  have  found  in  the  gulf  of  Genoa  species  identical 
with  those  of  our  Hebridean  coast,  and  vice  versd.^^ 

Fossil  Foraminifera. — In  a  fossil  form  the  PolytJialamia  are  very  common, 
and  enter  largely  into  the  formation  of  several  rocks,  chiefly  calcareous  or  of 
the  tertiary  series,  m  every  part  of  the  world.  Ehrenberg,  in  his  microscopic 
examination  of  the  chalk  formation,  represents  these  shells  as  the  most  im- 
portant constituent ;  and  Dr.  Bailey  speaks  of  them  as  largely  concerned  in 
the  formation  of  the  tertiary  rocks  of  South  Carohna,  and  adds,  they  '*are  still 
at  work  in  countless  thousands  on  her  coast,  filling  up  harboui^s,  forming 
shoals,  and  depositing  their  shells  to  record  the  present  state  of  the  sea- 
shore, as  theii^  predecessors,  now  entombed  beneath  Charleston,  have  done  with 
regard  to  ancient  oceans.  For  the  city  just  named  is  built  on  a  marl  236  feet 
thick.  The  marls  from  the  depth  of  110  to  193  feet  are  tertiary,  as  also, 
in  aU  likelihood,  are  those  beneath,  extending  from  193  to  309  feet,  and  also 
of  the  Eocene  epoch.  The  lithological  characters  of  the  marls  from  236  to 
309  feet  differ  from  those  above  them,  although  many  of  the  same  species  are 
stiU  to  be  detected  "  {A.  N.  H.  1845,  vol.  xv.). 

The  most  abimdant  Foraminifera  of  the  chalk  belong  to  Eotalia,  Spirulina, 
and  Textilaria :  the  fossil  genus  Nummulina  abounds  in  tertiar}^  strata ;  and 
their  shells  constitute  the  chief  ingredient  in  the  composition  of  many  lime- 
stone rocks  used  in  building,  such  as  those  in  Egypt,  from  which  the  huge 
stones  of  the  Pyramids  are  quarried.  In  America  this  genus  is  largely  re- 
placed, as  a  component  of  limestone,  by  the  genus  Orhitoides.  Species  of 
Textilaria  are  the  most  abundant  in  Oolitic  formations.  In  the  cretaceous 
earths,  says  D'Orbigny,  genera  and  species  augment  in  rapid  progression  from 
the  lower  to  the  higher  formations.     On  arriving  at  the  tertiary  rocks,  Fora- 


232  GENERAL  HISTOEY  OF  THE  INFUSOEIA. 

minifera  become  still  more  multiplied,  and  many  previously  unobserved  genera 
make  their  appearance.  In  the  Silurian  and  Devonian  rocks  of  the  palaeozoic 
series,  Foraminifera  appear  to  be  absent.  In  the  carboniferous  deposits 
D'Orbigny  found  one  species,  but  detected  none  in  the  Permian,  Triassic,  or 
Jui'assic  strata.  Mr.  King  has,  however,  discovered  shells  in  the  Permian  rocks. 

Many  genera  have  hitherto  been  found  only  in  the  fossil  state  :  some  such 
we  may  suppose  to  have  become  extinct ;  but  others  will  probably  be  discovered 
when  the  search  after  hving  specimens  is  further  prosecuted.  It  may  be 
generally  stated  that  the  relative  number  of  identical  fossil  and  recent  species 
is  much  greater  in  this  family  of  Foraminifera  than  in  any  other  known ;  and 
specific  forms  have  continued  from  the  Mesozoic  era  until  the  present  day,  so 
connecting,  as  by  an  imbroken  chain,  the  fauna  of  our  own  time  and  that  of 
almost  countless  ages  past. 

QuESTION^  OF  THE   CeLL-NATUEE    OP    EhIZOPODA,  AND    OF   THE    ChAEACTER    OF 

Foraminifera  as  Individuals,  or  as  Colonies  of  Aniiials. — The  prevailing 
theory  of  the  cellular  composition  of  all  animal  and  vegetable  tissues  induced 
several  distinguished  naturalists  to  represent  the  Rhizopoda  as  ceUs.  KoUiker 
ingeniously  argued  (J.  M.  S.  1853,  i.  p.  101)  in  favour  of  this  view,  and  for 
a  time  succeeded  in  persuading  most  scientific  men  of  its  truth.  It  had  the 
character  of  a  grand  generalization,  and  recommended  itself  by  its  simphcity. 
Yarious  structural  peculiarities  and  general  considerations  are,  however, 
opposed  to  this  theory:  these  we  will  adduce  after  KoUiker's  arguments 
have  been  stated.  He  first  assumes  that  the  Rhizopoda  and  Ciliated  Pro- 
tozoa are  comprehended  in  a  single  class  of  simple  animals,  which,  like  the 
Gregarince,  are  unicellular ;  and  he  foi^ther  groups  the  Actinophryina  with 
Rhizopoda.  The  absence  of  an  integument  to  represent  the  cell-wall,  and 
in  most  of  them  of  a  recognized  nucleus,  are  difficulties  he  would  explain 
away.  Pirst,  he  supposes  that,  where  a  nucleus  is  not  seen,  it  "  may  have 
existed  at  an  earlier  period,  and  be  absent  only  in  the  full-gro^vn  animal,  or, 
again,  that  it  may  be  entirely  wanting,  and  stiU  the  animal  be  regarded  as  a 
cell."  Secondly,  "  with  respect  to  the  membrane,  it  may  be  regarded  as  certain 
that  there  are  cells  mth  a  membrane  of  such  extreme  tenuity  as  to  be  hardly 
distinguishable  from  the  contents,"  and  others  in  which  at  a  later  period  all 
difference  between  the  membrane  and  contents  disappears, — for  instance,  the 
elements  of  the  smooth  muscles  of  the  higher  animals."  AATiich  of  these  two 
possible  conditions  obtaias  in  the  Rhizopods,  he  cannot  undertake  to  say,  but 
would  remark  ''  that  their  other  relations  are  not  opposed  to  the  notion  that 
they  may  be  simple  cells, — such  as  their  stnictureless  homogeneous  contents, 
their  contractihty,  and  the  vacuoles  which  occur  in  them,  resembling  in  all 
respects  the  contents  of  the  body  of  unicellular  Infusoria.  So,  likewise,  the 
simplicity  of  their  form  and  mode  of  taking  food,  so  closely  resembhng  the 
way  in  which  Infusoria  introduce  a  morsel  into  their  parenchyma.  Certainly 
the  presence  of  a  ceU-membrane  is  scarcely  reconcHeable  vrith  the  circumstance 
that  the  body  is  capable  of  admitting  a  morsel  of  food  at  any  part  of  the  sur- 
face ;  but  in  one  point  of  view  it  is  not  indispensably  necessary  to  assume 
that  such  exists  in  the  fully-developed  Actinoplirys,  and  in  another  it  is  by 
no  means  wonderful  that  a  membrane,  in  consistence  almost  the  same  as  the 
rest  of  the  parenchyma,  should  be  capable  of  being  torn  and  of  reuniting." 
It  is  therefore,  he  concludes,  best  to  consider  the  Rhizopoda  simple,  although 
modified,  cells,  especially  since  there  is  little  else  to  be  made  of  them.  "  It 
cannot  be  admitted  that  they  consist  of  a  whole  aggregation  of  cells  ;  and  as 
little  is  it  to  be  supposed  that  they  are  simply  a  mass  of  animal  matter  with- 
out further  distinction — as  it  were,  independent  hving  ceU-contents.  And 
the  less  can  this  opinion  be  entertained,  because  "  cells  are  the  elementary 


OF  THE  PEOTOZOA. EHIZOPODA.  233 

parts  of  the  higher  animals  and  plants,  and  the  unicellular  condition  the 
simplest  form  in  the  animal  kingdom."  The  existence  of  an  investing  mem- 
brane in  the  Rhizopoda  he  finally  considers  probable. 

The  arguments  here  quoted  from  Kolliker's  paper  on  Actinophrys,  have  been 
examined  by  several  later  writers,  and  have  had  their  defects  pointed  out. 
Perty  declares  himself  opposed  to  the  cell-theory  since  Ehizopocla  are  want- 
ing the  essentials  of  the  cell-nucleus  and  cell-wall ;  and  the  hypothesis  cannot 
be  applied  to  animals  composed  not  of  cells,  but  of  an  amorphous  primitive 
substance. 

M.  Claparede  attacks  Kolliker's  arguments  in  detail.  The  question  raised, 
whether  the  nucleus  and  membrane  may  not  disappear  in  the  course  of 
growth,  he  answers  by  another  queiy — "  \Ye  may  conceive  the  possibility  of 
this ;  but  where  do  we  find  any  proof  of  it  ?  " — and  proceeds  to  remark  his  own 
failure,  and  that  of  Ehrenberg  and  of  most  others,  to  discover  a  nucleus,  even 
in  very  small  animals,  and  after  treating  them  with  dilute  acetic  acid.  "  The 
supposition,  that  Actinoplirys  and  other  Ehizopoda  pass  through  a  previous 
cellular  condition,  has  consequently  no  foundation  in  fact."  He  cannot  agree 
with  Kolliker,  that  of  the  three  parts  of  a  cell — the  nucleus,  membrane,  and 
contents — two  "  may  be  deficient, — that  for  example,  we  may  attribute  the 
signification  of  a  cell  to  the  contents  remaining  alone  and  contained  in 
nothing ....  If,  therefore,  with  Kolliker,  we  regard  the  Ehizopoda  as  a  class 
of  unicellular  animals,  the  organisms  which  it  includes  will  be  principally 
distinguished  by  their  having  nothing  to  do  with  cells,  as  they  consist  of  a 
shapeless  mass  of  a  stinictureless  homogeneous  substance." 

M.  Claparede  next  subjects  to  examination  the  argument  for  the  cell-nature 
of  Ehizopoda  deduced  fi^om  analogy  with  Ciliated  Protozoa,  which  Kolliker 
takes  for  granted  to  be  unicellular  organisms.  This  assumption,  and  conse- 
quently the  analogy  dependent  on  it,  are  shown  to  be  erroneous ;  and  then 
the  wiiter  goes  on  to  say  that,  ''.even  if  we  admitted  that  Actlnophrys  was 
the  equivalent  of  a  cell,  it  would  still  not  be  unicellular,  inasmuch  as  an 
endogenous  cell-production  has  taken  place  in  it.  The  contractile  vesicle  is 
nothing  but  a  cell"  invested  by  a  membrane ;  and  this  being  the  case,  the 
existence  of  such  a  membrane  in  other  Ciliated  Protozoa  becomes  all  the  more 
probable.  "  Kolliker  himself  supposes  that  the  contractile  vesicle,  when  pre- 
sent, is  the  equivalent  of  a  cell-membrane  ;  and  with  the  proof  of  the  exist- 
ence of  such  (an  endogenous)  formation  in  Actinophrys,  his  hy^Dothesis  of  the 
unicellular  constitution  of  the  animal  consequently  falls  to  the  ground." 
Leuckart  has  also  briefly  argued  against  the  cell-theory  of  Ehizopoda ;  but 
as  no  novel  views  are  taken  of  the  question,  we  shall  not  quote  his  remarks. 
Our  own  opinion  is,  that  to  insist  upon  the  unicellular  nature  of  Ehizopoda 
and  of  other  Infusoria  is  to  limit  the  operations  of  natiu^e,  in  the  manifesta- 
tion of  animal  life,  to  one  sort  of  mechanism,  as  though  life  could  not  be 
exhibited  except  by  an  organic  substance  enveloped  by  a  membrane  and 
enclosing  a  nucleus.  Eeasoning  by  analogy  should  teach  us  differently ;  for 
everywhere  in  the  animal  series  do  we  see  ty^Dcs  or  grades  of  organization 
progressively  developed  from  theii^  simplest  to  a  more  or  less  complicated 
degree,  as  if  nature  would  show  us  by  how  many  different  plans  she  can 
attain  similar  and  equally  beneficial  results.  And  are  not  the  Ehizopoda  an 
illustration  of  this  fact,  an  example  of  the  establishment  of  independent 
animality  in  primordial  animal  matter,  and,  as  in  the  case  of  the  multilocular 
Polythalamia,  of  the  possible  extent  of  development  tliis  simple  type  may 
undergo  without  the  separation  or  addition  of  any  other  definite  structural 
element  ? 

If  Schneider's  researches  be  confirmed,  we  must  admit  several  Ehizopoda 


234  GENERAL  HISTORY  OF  THE  INFUSORIA. 

to  be  possessed  of  a  nucleus.  On  the  other  hand,  a  large  number  of  species 
are  able  to  produce  new  individuals  by  the  mere  detachment  of  a  portion  of 
theu'  sarcode  substance, — an  act  in  which  no  nucleus  is  concerned,  whereas 
in  cell-propagation  by  fission  a  preparatory  section  of  the  nucleus  appears  a 
necessary  process.  In  the  Ehizopoda,  therefore,  we  may  conclude  that,  in 
the  language  of  Professor  Owen,  "  the  spermatic  force  "  is  diffused  through- 
out their  entire  substance,  and  not,  as  it  were,  concentrated  in  a  particular 
organ  or  nucleus. 

The  question  respecting  the  nature  of  the  many-chambered  Foramin'ifera, 
whether  thej"  are  to  be  considered  single  individuals  or  colonies  of  animals,  is 
elaborately  examined  by  Schultze,  who  comes  to  the  conclusion  that  the 
inhabitant  of  each  shell  is  a  single  animal.  Ehrenberg  is  the  supporter  of 
the  opposite  view ;  but  Schultze  shows  that  several  structural  details  given 
by  him,  upon  which  the  colony-theoiy  is  partly  established,  are  erroneous, 
and  that  it  is  one  common  connected  substance  which  occupies  each  and  every 
chamber.  Prof.  Williamson  {T.  M.  S.  1851)  has  the  following  pertinent 
observation  on  this  colony-theory.  Speaking  of  the  Orbiculhia  adunca,  he 
says — ''  The  attempt  to  isolate  the  various  portions,  and  to  raise  each  portion 
to  the  rank  of  an  individual  animal,  even  in  the  limited  sense  in  which  we 
should  admit  such  a  distinction  in  the  polypes  of  a  Sertidaria  or  of  a  Gorgonia, 
appears  to  me  wholly  inadmissible."  Moreover,  the  soft-structiu'es  being 
devoid  of  visible  organization,  "  the  whole  animal  wiU  be  very  httle  raised 
above  the  Polypifera,  only  possessing  a  symmetrical  calcareous  skeleton, 
which  is  at  once  both  external  and  internal "  (/.  e.  the  Porifera). 

Of  THE  Affinities  of  Ehizopoda. — That  the  Ehizopoda  constitute  a  class 
of  animalcules  distinct  from  every  other  is  evidenced  by  their  characteristic 
\T.tal  structure  and  phenomena,  their  power  of  producing  their  like,  their 
growth,  theii'  faculty  of  digesting  and  appropriating  nutrient  matters,  and  by 
the  ascending  stages  of  development  seen  among  them,  advancing  fi'om  the 
simple  Amoeba  to  the  compound  testaceous  Cristellaria  and  Polystomella. 

In  the  natiu'e  of  their  animal  portion  they  resemble  Cihated  Protozoa ;  it  con- 
tains similar  vacuolae  and  graniiles,  and  also  a  contractile  vesicle.  On  the  other 
hand,  they  differ  from  them  in  having  no  definite  outline  to  the  animal  tissue 
boimded  by  a  hmiting  membrane  or  integument,  and  particularly  in  possess- 
ing no  cilia,  which,  as  locomotive  organs,  are  replaced  by  the  pecuHar  and 
characteristic  pseudopodes.  In  variabHity  of  outline  an  approach  is  made  to 
Ehizopoda  by  some  genera  of  the  heterogeneous  family,  Enchelia  of  Ehi'enberg ; 
but  they  never  exhibit  any  such  changeable  character  as  the  siu'face  of  the 
former,  never  protrude  similar  variable  processes,  nor  present  a  circulation 
of  granules.  The  Dinohryina  might  perhaps  be  cited  as  affording  an  example 
of  a  considerable  variability  of  form ;  but  our  knowledge  of  this  family  is  too 
incomplete  to  render  analogies  based  on  it  of  value. 

The  affinity  between  Ehizopoda  and  Phytozoa  is  no  closer.  Some  of  the 
latter  can  greatly  modify  their  form  in  mo\dng  ;  but  in  none  does  this  partake 
of  the  character  and  extent  of  the  variability  exhibited  by  Ehizopods.  More- 
over in  none  are  variable  processes  found,  but  in  general  one  or  more  elon- 
gated cilia  or  filaments,  which,  by  their  imdulation,  serve  as  the  principal  organs 
of  locomotion. 

Between  the  Testaceous  Ehizopoda  and  CHiated  Protozoa  the  alhance  is  even 
less  evident ;  for  in  none  of  the  latter  do  we  meet  "\;\ith  shells  like  those  of  the 
former,  and  in  none  is  the  relation  between  a  lorica  and  its  contents  corre- 
spondent to  that  of  the  shell  and  sarcode  substance  of  Ehizopoda.  It  has 
already  been  noted  that  the  distinction  between  the  two  classes  of  Protozoa 
founded  on  the  silicious  character  of  the  shells  or  lorica)  of  the  Ciliated,  and 


OF  THE  PEOTOZOA. EHIZOPODA.  235 

the  calcareous  natiu'e  of  those  of  the  Pseudopodoiis  class,  is  not  in  accordance 
with  fact ;  for  although  all,  or  almost  all,  Polythalamla  have  calcareous  shells, 
yet  the  flexible  loricse  of  many  Monothalamia  are  chitinous,  just  as  those  of 
loricated  Ciliata. 

In  the  presumed  fact  of  the  shells  of  Arcellina  being  silicious,  Ehrenberg 
discovered  a  relation  betTs^een  that  family  and  the  Bacillaria.  This  affinity  he 
traced  still  further ;  for,  when  describing  the  genus  CyphkUum,  he  remarked 
— '^  It  forms  a  connectmg  group  between  ArceUa  and  Bacillaria,  by  reason  of 
the  simple  locomotive  organ  (like  a  snail's  foot),  and  approaches  very  closely 
to  the  group  Desmidieoi"  However,  even  if  he  be  right  as  to  the  single  un- 
divided process  of  Cyphidium,  the  presence  of  any  extended  foot  or  pedal 
organ  from  the  silicious  fronds  of  EaciUaria,  whether  Diatomew  or  Desmidiece, 
is  not  now  admitted  by  any  natui^alist. 

If  Stein's  observations  and  opinions  be  correct,  an  indirect  relationship 
actually  exists  between  Ciliated  Protozoa  and  Rhizopoda;  for  that  pains- 
taking observer  has  con\inccd  himself  that  the  VorticeUina,  by  ulterior  de- 
velopment, become  transfoiTaed  into  Aciiieta-]ike  or  Actinophryean  organisms, 
of  the  intimate  affinity  of  which  no  doubt  can  be  raised.  The  questions 
raised  by  this  apparent  transformation  do  not  require  discussion  here,  since 
they  are  fiilly  entered  upon  in  the  history  of  the  Ciliata,  and  in  that  of  the 
Acinetina,  considered  as  a  subclass  of  Rhizopoda. 

Another  alhance  was  formerly  assigned  to  the  Multilocular  Rhizopoda,  \-iz. 
mth  the  Cephalapoda,  of  which  they  were  treated  as  a  subdi\'ision.  This 
association  was  suggested,  by  the  ]Sfaidilus-]ike  form  of  some  genera,  to  the 
earliest  observers  of  the  Foraminifera — Beccarius  in  1731,  and  Plancus  in 
1739 ;  and  the  error  was  perpetuated  by  D'Orbigny  in  1826.  Dujardin  has 
the  great  merit  of  first  combating  this  mistaken  opinion,  and  of  pointing  out 
the  extremely  simple  nature  of  their  contents,  and  their  true  affinity  with  the 
simple  Amcebce. 

Several  natui'alists,  and  among  them  M.  de  Quatrefages,  have  classed  the 
comparatively  large  Noctilucce  with  the  Rhizopoda.  But  direct  observation 
seems  to  show  that,  although  in  a  few  particulars  a  likeness  obtains,  yet 
the  sum  of  the  differences  greatly  surpasses  that  of  the  resemblances.  The 
Noctilucoi  show  a  more  complex  organization ;  they  have  an  integument  com- 
posed of  two  layers,  an  evident  mouth  and  gastric  cavity  with  aj^pendages, 
and  motile  filaments,  but  no  variable  processes. 

A  striking  general  resemblance  subsists  between  the  ^N'aked  Rhizopoda — 
Amcebce — and  the  like  isolated  individuals  and  the  germs  of  freshwater  Sponges 
or  Spongilke,  which  Mr.  Carter  has  named  Proteans  (XXI.  5  a,  h,  c).  The 
resemblances  are  well  conveyed  in  the  following  quotation  from  Mr.  Carter's 
paper : — "  A  ragged  portion  torn  off  with  a  needle,  will  be  seen  gradually  to 
assume  a  spheroidal  form ;  and  if  there  be  a  spiculum,  it  wiU  embrace  it  within 
its  substance,  it  may  even  be  seen  to  approach  it,  and  it  may  bear  away  the 
spiculum,  having,  as  it  were,  spit  itself  upon  it.  On  its  circumference  ^vill  be 
obsei-ved  little  papiUse,  which  gradually  vary  theii-  form,  extending  and  retract- 
ing themselves,  imtil  one  of  them  may  be  seen  to  detach  itself  from  the  parent 
mass  and  go  off  to  another  object.  This  little  animal,  one  of  the  group  which 
it  has  left,  may  remain  stationary'  on  the  second  object,  or  descend  to  the 
watch-glass,  assuming  in  its  progress  aU  forms  that  can  be  imagined,  sphe- 
roidal or  polygonal,  whilst  every  point  of  its  body  appears  capable  of  ex- 
tending itself  into  a  tubular  attenuated  prolongation  ....  These  transparent 
little  sacs  (the  gemmules  of  Grant  and  Hogg)  are  sometimes  filled  with  green 
matter.  They  appear  to  be  able  to  adapt  themselves  to  any  form  that  may 
be  convenient  for  them  to  assume ;  and  when  forcibly  separated  from  each 


236  GElfEEAL  HISTOET  OF  THE  IK^FUSOEIA. 

other  (by  tearing  to  pieces  a  minute  portion  of  the  sponge  under  water  in  a 
watch-glass),  the  isolated  individuals  may  be  seen  to  approach  each  other, 
and  apply  themselves  together  in  twos  and  threes,  &c.  and  so  on,  until,  from 
a  particle  only  discernible  by  the  microscope,  they  assume  the  form  of  an 
aggregate  mass  visible  to  the  naked  eye ;  and  such  a  portion,  growing  and 
multiplying,  might  ultimately  reach  the  size  of  the  largest  masses  adhering 
to  the  sides  of  the  tanks  at  Bombay.  They  appear  to  belong  to  the  genus 
Am(eba  of  Ehrenberg." 

These  changeable  globules  Mr.  Carter,  in  the  subsequent  part  of  his 
paper,  designates  Proteans,  and  states  that  they  commonly  resemble  the  Pro- 
teus difflaens  (Miiller).  ("  Notes  of  the  species,  &c.  of  the  Fresh-water  Sponges 
of  Bombay,"  Trans.  Med.  and  Phys.  Society,  Bombay,  1847.  Appendix.) 

In  his  more  recent  contribution  on  the  freshwater  Sponges,  Mr.  Carter 
describes  ceUs,  capable  of  greatly  and  rapidly  changing  their  form,  endowed 
\^ith  considerable  motile  powers,  and  furnished  each  ^^dth  an  imdulating 
locomotive  filament  (XXI.  5).  These  organisms  he  considers  to  be  zoospcrms, 
or  the  speimatozoa  of  Sponyilla.  Speaking  of  one,  he  says — *'  When  its 
power  of  progression  and  motion  (of  a  serpentine  creeping  character)  beguis 
to  fail,  and  if  separated  fi'om  other  fragments,  it  soon  becomes  stationary,  and, 
after  a  httle  polymorphism,  assumes  its  natural  passive  form,  which  is  that  of 
a  spherical  ceU.  Diu'ing  this  time  the  motions  of  the  tail  become  more  and 
more  languid,  and  at  length  cease  altogether."  On  the  other  hand,  it  may 
attach  itself  to  some  fragment,  or  to  another  cell,  and  "  become  indistinguish- 
able fi^om  the  common  mass ;  and  the  tail,  floatrag  and  undulating  outwards, 
is  all  that  remains  ^'isible."  In  these  structures  there  is,  therefore,  polymor- 
phism as  in  Rhizopoda,  but  no  actual  extrusion  of  pseudojjodes ;  and  the  points 
of  agreement,  after  all,  are  realty  accidental,  and  not  demonstrative  of  a 
structiu^al  affinity.  In  them  we  have  reproductive  germs,  which  coalesce  and 
disappear  as  independent  existences,  whilst  in  the  case  of  Amoeba  each  speci- 
men is  an  independent  individual,  and  is  never  seen  to  coalesce  with  others 
mto  a  common  or  sponge -hke  mass. 

Dujardin  devoted  a  couple  of  pages  to  speak  of  this  affinity  between  ^?>zo?6ce 
and  Sponges  ;  and  Perty  even  goes  so  far  as  to  make  the  latter  a  third  class  of 
the  Ehizopoda,  intermediate  between  Arcellina  and  Amoebina,  on  account  of 
the  calcareous,  silicious,  or  homy  spicula  which  occur  in  their  compound 
mass,  and  constitute  a  sort  of  skeleton. 

The  affinity  ^vith  Sponges  is  traceable  even  in  the  case  of  the  testaceous 
Polytlialamia,  as  Prof.  AVilliamson  pointed  out  in  1848,  and  in  a  subsequent 
memoir  in  1851  {Trans.  Mic.  Soc.)  thus  enters  on  the  question  : — "  Looking  at 
the  structiu-e  of  the  shell  of  the  Orbicidina  adunca,  and  esj)ecially  at  the  large 
orifices  which  communicate  between  its  various  cavities,  we  cannot  fail  to 
observe  that  it  is  a  reticulated  calcareous  skeleton,  whose  proportionate  rela- 
tion to  the  size  of  the  soft  animal  has  diff'cred  but  Kttle  from  that  of  the 
sihceo-keratose  network  of  many  Sponges  to  the  slimy  substance  "with  which 
they  are  invested." 

So  Dr.  Carpenter  (Proc.Roy.  Soc.  18.55),  in  his  critical  examination  of  Orbito- 
lites,  "  places  that  genus  among  the  lowest  forms  of  Foramrnifera,  and  con- 
siders that  it  approximates  closely  to  Sponges,  some  of  which  have  skeletons 
not  very  unlike  the  calcareous  network  which  intervenes  between  its  fleshy 
segments."  AYith  respect  to  this  idea  of  Dr.  Cai^penter,  that  they  are  allied 
to  Sponges,  Mr.  Jeifi'eys  (same  journal)  would  remark  "  that  Polystomella 
crispa  has  its  peripheiy  set  roimd  at  each  segment  with  sihcious  spicula,  like 
the  rowels  of  a  spiu\  But  as  there  is  only  one  terminal  cell,  which  is  con- 
nected A\ith  all  the  others  in  the  mterior  by  one  or  more  openings  for  the 


OF  THE  PEOTOZOA. HHTZOPODA. 


237 


pseudopodes,  the  analogy  is  not  complete,  this  being  a  solitary,  and  the  Sponge 
a  compound  or  aggregate,  animal."  In  a  previous  pag-e  the  theoiy  of  Ehi-en- 
berg,  that  the  Fomminifera  are  compound  or  aggregate  animals,  has  been 
referred  to.  It  was  on  this  hypothesis  that  he  assumed  theii*  affinity  with 
Polypes — with  Flustrae  and  Bryozoa,  at  the  head  of  which  he  arranged  them. 
This  association,  like  the  hypothesis  it  rests  upon,  is  untenable.  In  his 
work  on  the  Foraminifera  of  the  Vienna  basin,  M.  D'Orbigny  assigned  a 
position  to  these  animals  as  an  independent  class  between  Echinodeims  and 
Polypes,  which,  from  the  present  knowledge  of  the  structui^e  and  reproduc- 
tion of  those  classes,  we  cannot  suppose  he  would  seek  to  maintain. 

CLASSiFiCATioif  OF  Ehizopoda. — The  fii'st  division  of  Rhizopoda  that  suggests 
itself  is  into  naked  and  testaceous  forms,  or,  as  Ehrenberg  would  say,  into 
illoricated  and  loricated.  The  naked  forms  constitute  the  family  Amoehma, 
represented  by  the  single  genus  Amoeba. 

The  determination  of  specific  characters  in  this  family  is  attended  by  almost 
insurmountable  difficulties,  and  can  only  be  imsatisfactoiy,  by  reason  of  the 
absence  of  any  definite  figiu^e,  and  of  determinate  organs  or  parts.  More- 
over the  semiiluid  body  of  any  one  presumed  species  must  be  much  influenced 
by  external  causes,  and  in  some  measui-e  by  the  matters  which  may  have 
entered  into  its  substance ;  and  the  like  causes  will  doubtless  operate  by 
modifjing  the  outline,  dimensions,  and  number  of  the  processes.  Among 
such  causes  the  density  of  the  liquid  in  which  they  live,  and  the  quantity  of 
organic  matter  contained  in  it,  may  be  particularly  mentioned.  Claparede 
remarks — "  It  appears  almost  absurd  to  attempt  the  distinction  of  species 
amongst  the  Amoehce  until  we  know  something  more  of  their  intimate 
organization.  Thus  Ehrenberg' s  A.  radiosai^  characterized  by  the  regularity 
of  its  processes,  and  its  generally  stellate  form  when  at  rest ;  but  when  the 
creature  creeps,  it  slowly  expands  and  the  peculiar  outline  disappears;  it 
flows  along  like  a  cloudy  veil  or  di-op  of  oil,  and  A.  radiosa  has  become  converted 
into  A.  diffluens.^^  Yet,  this  author  afterwards  goes  on  to  say — "even  the 
changeable  Amoebce  have  their  ty[ncal  forms,  such  as  the  stellate  and  globu- 
lar." Other  grounds  of  specific  distinction  (of  no  very  certain  value,  indeed) 
are  foimd  in  the  shape,  length,  and  mode  of  termination  of  the  variable  pro- 
cesses, and  in  the  size,  colour,  transparency,  activity,  and  habitats  of  these 
bemgs. 

The  Testaceous  Ehizopoda  natiu-ally  fall  into  two  groups, — one  distinguished 
by  having  a  unilocular,  the  other  a  multilocular,  shell — the  former  called,  by 
Sehultze,  Monotlialamia,  the  latter,  Polythalamia  or  Foraminifera.  These 
grand  di\isions  have  been  recognized  by  every  natiu^alist ;  but  some  have  been 
led,  from  giving  importance  to  other  particulars,  to  arrange  difierently  cer- 
tain genera,  or,  otherwise,  to  detach  some  as  additional  families. 

Thus  Ehrenberg,  swayed  by  his  polygastric  hypothesis,  and  satisfied  in  his 
own  mind  that  the  ArceUce,  Difflugice,  and  one  or  two  other  monolocular  genera 
possessed  a  series  of  stomachs  and  other  organs  like  other  Polygastria,  imited 
those  genera  into  a  family  which  he  caUed  Arcellina.  This  detachment  of  one 
group  of  pseudopodous  beings  from  the  rest,  he  further  justified,  as  heretofore 
stated,  by  representing  it  to  have  sihcious  instead  of  calcareous  shells.  In 
this  dislocation  of  evidently- aUied  forms  he  finds  no  imitators,  and  is  unsup- 
ported by  facts. 

D'Orbigny  distinguished  the  one-chambered,  sac-like,  shelled  Ehizopoda 
as  one  of  the  six  orders  into  which  he  separated  the  Foraminifera,  and  named 
it  Monostegia.  This  order  is  nearly  equivalent  to  that  framed  by  Ehrenberg, 
under  the  title  of  Monosomatia,  to  comprehend  the  genera  Gromia,  Orhidina, 
and  Ovidina, — a  term  subsequently  borrowed  by  Siebold,  but  extended  by  him 


238  GENEEAL  HISTOEY  OF  THE  INFUSORIA. 

SO  as  to  include  not  only  the  particular  genera  enumerated,  but  also  the' 
families  Anuiehce  and  AreeUma  of  that  naturalist. 

The  term  Monothalamia  contrasts  \Yell  mth  that  of  Poh/thalamia,  expresses 
the  fact,  and  involves  no  hyi)othesis  as  do  Ehrenberg's  words  Monosomatia 
and  Pol  y  so  mat  i  a,  which  are  foimded  on  his  belief  in  the  colony-like  aggrega- 
tion of  several  individuals  ^vithin  a  Poraminiferous  shell. 

The  Monothalamia  of  Schultze  (as  before  remarked)  do  not  precisely  cor- 
respond with  the  one-celled  group  of  either  of  the  other  authors  named  ;  for, 
besides  the  Monostec/ia  of  D'Orbigny,  it  comprehends  the  Arcellina  of  Ehren- 
berg  and  a  few  other  new  genera.  The  groupings  and  relations  of  the  several 
species  are  represented  in  the  appended  table  exhibiting  Schultze's  system. 

In  the  classification  of  the  Monothalamia  certain  and  constant  characters  are 
deducible  from  the  shells,  whilst  those  ch'a^Mi  from  the  soft  parts,  from  the 
length  or  tenuity  or  mode  of  termination  of  the  pseudopodes,  are  of  compara- 
tively secondary  importance,  and  not  to  be  relied  on  alone.  Definite  charac- 
ters are  deiivable  from  the  figm^e,  size,  composition,  sculptimng  or  appendages, 
and  colour  of  the  entii^e  shell,  from  the  presence  of  a  single  large  aperture  or 
of  many  small  pores,  and  from  the  form  of  the  apertiu'e  and  of  its  margin ; 
consequently  it  is  in  the  shells  of  the  Polythalamia  that  we  must  seek  generic 
and  specific  distinctions.  As  animals,  they  have  all  alike  the  same  sarcode  sub- 
stance, which  extrudes  similar  variable  fibres  :  hence  any  diversities  observed 
in  its  colour  or  transparency,  in  its  contents,  or  in  the  maimer  in  which  the 
processes  are  extruded  or  other^^ise  comport  themselves,  serve  but  a  sub- 
ordinate purpose  in  the  scheme  of  classification.  On  the  contrary,  the  cha- 
racters of  the  shells  are,  Avithin  certain  limits,  determinate  and  fixed.  They 
are  derivable  from  the  figure,  size,  coloiu%  and  consistence  of  the  shell ;  from 
the  markings,  processes,  pores,  and  slits  occupying  its  surface;  from  the 
relative  position  and  figiu'e  of  the  several  chambers;  from  the  mode  and 
degree  of  their  connexion  ;  and  from  the  presence  or  absence  of  large  apertm^es 
in  company  Avith  the  usual  foramina ;  and  last,  not  least,  from  the  intimate 
structiu'e  of  the  shell.  Dujardin  recognized  the  value  of  the  shells  to  supply 
the  basis  of  a  classification  of  the  Rhizopoda  ;  but  he  had  recoui'se  to  the  form 
of  the  variable  expansions  to  make  his  primary  di\-ision,  "  although,"  as  he 
remarks,  *'  it  has  no  absolute  value."  He  arranged  all  the  Rhizopoda,  with 
the  exception  of  the  Amcehce  (which  he  treats  as  a  distinct  family),  into  two 
sections, — one  having  a  single  unilocular  shell  mth  a  single  large  apertui-e ; 
the  other  a  foraminiferous  compound  shell,  or  one  having  several  aggregated 
chambers,  each  ^^ith  a  simple  orifice,  as  represented  by  the  tribe  Miliola.  It 
is  in  the  subdivision  of  these  sections  that  he  employs  characters  derived  from 
the  variable  processes.  Thus  he  separates  the  first  into — 1.  those  animals  pro- 
vided with  short  and  thick  processes  rounded  at  the  extremities,  viz.  Difflugia 
and  ArceIJa ;  and  2.  into  those  having  filiform  expansions,  acutely  drawm  out 
at  the  ends.  The  latter  di\ision  is  more  largely  represented  ;  and  he  separates 
its  numerous  species  into  three  tribes,  viz.  Trinema,  with  a  lateral  orifice ; 
Euglypha,  with  a  tuberculated  or  areolated  shell  and  few  sim2:)le  exj^ansions ; 
and  Gromia,  with  a  membranous  spheroidal  shell  and  expansions,  thick  at 
the  base,  but  very  long  and  branching.  He  has  not  attempted  the  classifica- 
tion of  the  whole  of  the  Foraminifera,  but  restricted  his  accoimt  to  some  few 
genera  which  he  has  foimd  in  a  living  condition. 

D'Orbigny  instituted  five  orders  of  the  PolijtliaJamia,  viz. — 1.  Stichostegia, 
having  the  ceUs  arranged  one  above  another  in  a  straight  or  shghtly-curved 
line  ;  2.  Helicostegia,  ^ith  cells  disposed  spirally  around  an  axis ;  3.  Ento- 
mostegia,  having  the  chambers  alternating  and  coiled  spii\ally ;  4.  EnalJo- 
stegia,  with  alternating  but  not  spirally-disposed  chambers  ;  5.  Agathistegia, 


OF  THE  PROTOZOA . RKTZOPODA.  239 

ha\ing  the  cells  spirally  arranged,  but  each  one  occupying  only  one-half  the 
circuit. 

The  three  sections  proposed  by  Schultze  are — 1.  shells  disposed  in  recti- 
linear series  or  in  a  slightly- curved  line,  Bliahdoidea  ;  2.  those  coiled  in  a 
spii'al,  HeUcoidea  ;  3.  those  irregularly  aggregated,  Soroidea.  The  first  of 
these  corresponds  to  the  SticJiostegia  of  D'Orbigny ;  the  second  includes  all 
the  remaining  orders  of  that  wiiter ;  whilst  the  third  section  is  represented 
by  a  small  number  of  species,  previously  itn  mentioned,  vrhich  Schultze  unites 
in  the  genus  Acervulina. 

^\Tiat  structural  peculiarities  should  be  employed  to  determine  species,  is  a 
question  now  much  mooted  \\dth  respect  to  the  Foraminlfem.  In  reference 
to  this  subject,  Dr.  Carpenter  (in  the  annual  address  at  the  Microscopic  So- 
ciety, Feb.  1855)  obsei-ved  "  that  a  large  proportion  of  the  species,  and  even 
of  the  genera,  which  have  been  distinguished  by  systematists,  and  especially 
by  M.  D'Orbigny,  have  no  real  existence,  being  nothing  else  than  individual 
varieties."  This  error  is  at  once  accoimted  for  by  M.  D'Orbigny's  mode  of 
proceeding  (as  stated) :  "for  that,  in  examining  any  new  collection,  he  set 
an  assistant  to  pick  out  the  most  divei^gent  forms,  and  then  described  all  that 
might  prove  new  to  him  as  distinct  species,  mthout  troubling  himself  in  the 
least  about  those  connecting  links,  the  existence  of  which  should  have  at  once 
convinced  him  that  he  was  following  an  altogether  wrong  method.  Through- 
out the  whole  of  his  labom\s  on  the  group,  in  fact,  I  find  the  influence  of  the 
erroneous  ideas  which  he  originally  entertained  ^^ith  regard  to  the  natiu-e  of 
the  animal  of  the  Fomminifem ;  for  in  the  formation  of  his  orders,  as  well 
as  of  his  genera  and  species,  he  has  proceeded  as  if  the  characters  of  the  tes- 
taceous skeleton  were  of  the  same  distinctive  value  when  its  construction  is 
due  merely  to  the  solidification  of  the  siuface  of  a  minute  fragment  of  animal 
jelly,  which  is  subject  to  an  almost  indefinite  variation  both  in  size  and  in 
shape,  as  when  it  belongs  to  a  moUusk  of  high  organization,  the  plan  of 
whose  conformation  is  definitely  fixed ....  When  a  collection  is  brought  to- 
gether containing  large  numbers  of  individuals  of  one  generic  type,  which 
appear,  however,  to  belong  to  several  distinct  species,  it  very  commonly  hap- 
pens that,  although  it  would  be  easy  to  make  6,  8,  12,  or  20  species  by 
selecting  the  most  divergent  forms,  yet,  when  the  attempt  is  made  to  sort 
the  entire  collection  under  these  tj^pes,  only  a  part  of  it  can  be  unhesitatingly 
arranged  aroimd  them  as  centres,  the  remainder  being  transitional  or  inter- 
mediate forms,  for  which  another  set  of  species  must  be  made,  if  the  principle 
of  separation  be  once  adopted.  In  fact,  to  such  an  extent  does  individual 
variation  often  go,  that  (as  in  the  case  of  the  human  race)  no  two  specimens 
are  precisely  alike,  and  there  is  no  satisfactory  medium  between  grouping 
them  all  as  varieties  of  one  species,  and  making  every  individual  a  species,  which 
is  manifestly  absurd." 

The  error  of  D'Orbigny  has  not  escaped  Schultze's  notice ;  for  in  his  chapter 
on  classification  he  has  repeatedly  pointed  out  the  insufiiciency  of  the  charac- 
tei-s  on  which  that  observer  relied  in  framing  his  species,  genera,  and  families. 
For  instance  (p.  52),  he  points  out  the  erroneous  separation  of  the  Stichoster/ia 
(D'Orb.  j  into  two  families,  according  to  the  equilateral  or  inequilateral  con- 
dition of  the  shell.  And  further  on,  he  remarks  that  the  variations  elevated 
by  D'Orbigny  to  the  rank  of  specific  distinctions  are  merely  accidental  diver- 
sities in  growth,  connected  together  by  every  intermediate  variety.  Hence, 
for  example,  he  combines  the  genera  Trilocidina  and  Quinquelocidina  (D'Orb.) 
into  one  genus  MilioJa,  and  the  Orhitoides  and  Orbitulina  (D'Orb.)  into  a 
single  genus  Orhitolites.  Various  other  illustrations  might  be  adduced,  for 
instance,  the  family  Nautiloidce  ;  but  it  is  unnecessaiy  to  muluply  them.    It 


240 


GENEE,AL  KISTORT  OF  THE  INFUSORIA. 


is  only  fair,  however,  to  state  that  D'Orbigny  is  not  alone  guilty  of  unduly 
manufacturing  species,  but  that  Ehrenberg,  Reuss,  and  others  are  equally 
involved  in  the  fault,  which,  by  the  way,  is  one  almost  inseparable,  and 
therefore  very  excusable,  in  the  case  of  the  first  observers  and  systematists  of 
any  newly-discovered  group  of  organic  beings. 

Mr.  Jeffreys  {Proc.  Roy.  Soc.  1855)  deplores  the  multiplication  of  species 
and  genera  in  the  present  day,  and  observes  that "  the  Foraminifera  exhibit  a 
great  tendency  to  variation  of  form,  some  of  the  combinations  (especially  in 
the  case  oi  Margiyiulina)  being  as  comphcated  and  various  as  a  Chinese  puzzle. 
It  is,  I  beheve,  undeniable,  that  the  variability  of  form  is  in  an  inverse  ratio 

to  the  development  of  animals  in  the  scale  of  Nature I  am  induced  to 

suggest  the  following  arrangement : — 

"1.  Lagena  and  Entosolenia. 

"  2.  Nodosaria  and  Marginulina,  &c. 

"  3.   Vorticialis,  JRotcdia,  Lobatida,  and  GlohigeriTia,  &c. 

"  4.  Teoctularia,  Uvigerina,  &c. 

"  5.  Miliola,  Bdocidina,  &c. 

*'  This  division  must,  however,  be  modified  by  a  more  extended  and  cosmo- 
pohtan  view  of  the  subject,  as  I  only  profess  to  treat  of  British  species.  To 
illustrate  McLeay's  theory  of  a  quinary  and  cii'cular  arrangement,  the  case 
may  be  put  thus : — 


"  The  first  family  is  connected  by  the  typical  genus  Lagena  mth  the  second, 
and  by  the  Entosolenia  Avith  the  fifth ;  the  second  is  united  with  the  third 
through  Marginulina ;  the  third  with  the  foiu'th  through  Glohigerina ;  and 
the  fourth  with  the  last  through  Uvigerina  J' 

"VYe  append  a  tabular  view  of  the  groupings  into  families  and  genera,  as 
proposed  by  Prof.  Schultze,  since  it  presents  the  most  complete  system  yet  pro- 
duced, and  advances  much  nearer  a  true  arrangement  of  the  Foraminifera 
than  that  made  by  M.  D'Orbigny. 


OF  THE  PROTOZOA. RHIZOPODA.  241 

RHIZOPODA. 
A.  NUDA. 

G-en.  Amoeba  (Noctiluca?). 

B.  TESTACEA. 

I.    MONOTHA  LAMIA. 

Testa  or  shell  one-chambered ;  animal  imdivided,  having  the  same  conformation  as  the  shell. 

Fam.  1.  Lagvnida. — A  sacciform,  calcareous  or  membranous,  non-porous  testa,  with  a  large 
opening. 
Gen.  Arcella,  Difflugia,  Trinema,  Euglypha,  Gromia,  Lagynis,  Ovulina,  Fis- 
sm'ina,  Squamulina. 

Fam.  2.  Orbulinida. — A  globose,  calcareous  testa,  finely  porous  throughout,  without  a 
large  opening. 
Gen.  Orbulina. 

Fam.  3.  Cornuspirida. — A  calcareous  shell,  convoluted  like  that  of  a  Planorbis,  with  a 
large  opening. 
Gen.  Cornuspira. 

II.    POLYTHALAMIA. 

Shell  polythalamous ;  the  animal  composed  of  segments,  connected  by  commissural  bands. 

1.  G-roup  Helicoidea. 
The  chambers  disposed  in  a  spiral. 

Fam.  4.  Miljolida. — Each  chamber  occupies  a  half-spiral,  which  is  developed  either  in 
one  plane  or  in  various  planes.     The  shell  has  only  one  large  opening 
at  the  extremity  of  the  last  spiral,  and  no  pores. 
G-en.    Uniloculina,   Biloculina,    Miliola,   Spiroloculina,    Articulina,    Sphee- 
roidina,  Adelosina,  Fabularia. 

Fam.  5.  Turbinoida. — The  chambers  so  disposed  spirally  as  to  resemble  the  shell  of  Helix 
or  Tm-bo.     The  spiral  is  only  visible  on  one  side  of  the  shell.     Some 
are  so  much  elongated  that  the  chambers  are,  as  it  were,  disposed 
alternately  in  two  contiguous  rows.     The  shell  has  a  large  opening 
in  the  last  chamber,  and  its  sm'face  is  almost  always  finely  perforated. 
Subfam.  1 .    Rotalida. — Shell  flattened   or  conical ;    chambers  do  not  encircle  each 
other ;  shell  glass-like,  transparent ;  finely  perforated. 
Gen.  Rotalia,  Rosalina,  Trmicatulina,  Anomalina,  Planorbulina,  Asterigerina, 
Calcarina,  Siphonina,  Planulina,  Colpopleura,  Porospira,  Aspidospira. 
Subfam.  2.    Uvellida. — Shell  in  the  form  of  a  longer  or  shorter  cluster  like  a  bunch 
of  grapes.     The  chambers  frequently  appear  to  ahnost  completely 
embrace   one  another.      Shell  usually  thick  and  coarsely  perforate, 
or  solid. 
G-eh.  Globigerina,  Bulimina,  Uvigerina,  G-uttulina,    Candeina,    Globulina, 
Chrysalidina,  Pyrulina,  Clavulina,  Polymorphina,  Dimorphina,  Ver- 
neuillina,  Chilostomella,  Allomorphina,  Ehynchospira,  Strophoconus, 
G-rammobotrys. 
Subfam.  3.   Textilarida. — Spire  so  much  produced  that  the  chambers  form  a  double 
row  and  alternate. 
G-en.  Gaudryna,  Textilaria,  Virgulina,  Vulvulina,  Sagrina,  Bigenerina,  Bo- 
livina,  Gemmulina,  Cmaeolina,  Clidostomum,  Proroporus. 
Subfam.  4.   Cassidulinida. — Textilaridas  curved  once  in  a  direction  perpendicular  to 
the  original  spiral. 
Gen.  Ehrenbergina,  Cassidulina. 

Fam.  6.  Nautiloida. — The  chambers  so  disposed  spirally  that  the  shell  has  a  general 
resemblance  to  that  of  an  Ammonite  or  Nautilus.  The  spire  is  either 
visible  or,  otherwise,  concealed  on  both  sides  of  the  shell.  The  anterior 
wall  of  the  last  chamber  is  furnished  with  one  larger  or  several  smaller 
openings ;  the  other  portion  of  the  shell  is  usually  finely  perforated. 

Subfam.  1.     CristeUarida.—^\\e\\    thick,    finely   perforate,    colourless,    transparent; 
chambers  encircling,  -with  a  large  opening  at  the  upper  angle  of  the 
anterior  wall  of  the  last  chamber,  which  corresponds  in  position  with 
the  communicating  openings  between  the  sevei-al  chambers. 
Gen.  Cristellaria,  Robulina,  Marginulina,  Flabelliaa. 

Subfam.  2.  Nonionida. — Shell  thick  or  tliin,  colourless,  transparent,  finely  perforate ; 
chambers  either  encircling  (imbricate)  or  not.     The  opening  is  in  the 


242  GENEKAL  HISTOEY  OF  THE  INFUSORIA. 

anterior  wall  of  the  first  chamber  on  the  under  side  looking  towards 
the  penultimate  spiral ;  the  communicating  openings  of  the  several 
chambers  have  a  similar  position. 

Gen.  Nonionina,  Hauerina,  Orbignyna,  Fusulina,  Nummulina,  Assilina, 
Siderolina,  Amphistegina.  Operculina  and  Heterostegina  should  pro- 
bably be  formed  into  a  special  subfamily  of  Nonionida. 
Subfam.  3.  Peneroplida. — Shells  usually  thin,  always  brown,  and  transparent  with  or 
without  fine  pores  ;  the  chambers  very  narrow,  either  imbricate  or  not. 
Numerous  openings,  scattered  over  the  whole  of  the  anterior  wall  of 
the  last  chamber ;  or,  instead  of  these,  a  lai'ge  opening  produced  by 
the  coalescence  of  ntmierous  smaller  ones. 

Gen.  Peneroplis,  Dendritina,  Vertebralina,  Coscinospira,  Spii'olina,  Lituola. 
Appended  genus,  Orbiculina. 
Subfam.  4.  Polystomellida. — Shell  tolerably  thick,  colourless,  transparent,  finely  por- 
ous ;  chambers  imbricated ;  the  anterior  wall  of  the  last  chamber 
has,  besides  the  fine  pores,  either  no  larger  opening  at  all,  or  a  few 
very  small  irregular  scattered  fissures,  on  the  contrary  side  to  the 
penultimate  whorl.  The  same  applies  to  the  septa.  On  the  surface 
of  all  the  chambers,  rows  of  fissure-like,  often  perforating,  depressions 
are  placed  at  right  angles  to  the  direction  of  the  septum. 

Gen.  Polystomella. 

Fam.  7.  Alveolinida. — Globose,  ovoid,  or  barley-shaped  shells,  composed  of  spiral  tubes, 
each  resembling  a  cornuspira,  and  fm*nished  with  a  special  opening 
at  the  end  of  the  turn  or  spiral.  The  tubes  all  commimicate  by  con- 
necting openings,  and,  besides  this,  are  all  subdivided  by  incomplete 
dissepiments  (partitions),  in  the  same  manner  as  species  of  Nonionina. 
The  situation  of  these  septa,  which  are  but  few  in  number,  and  of  the 
coimecting  openings,  is  indicated  by  lines,  which  traverse  the  shell  in 
the  direction  of  meridional  lines. 
Gen.  Alveolina. 

Fam.  8,  Soritida. — Discoid,  multicellular  shells,  exhibiting  an  indication  of  a  helicoid 
spiral  only  in  the  centre ;  elsewhere  cycloid,  that  is,  growing  uniformly 
at  the  whole  border  of  the  disk.  The  brown,  transparent,  finely  porous 
shell  is  formed  of  minute  chambers,  connected  together  in  the  direc- 
tion of  straight  or  curved  radii,  and  each  presenting  a  large  opening 
at  the  border  of  the  disk. 
Gen.  Sorites,  Amphisorus,  Orbitulites.  Appended  genus,  Cyclolina  (cham- 
bers perfectly  annular,  with  numerous  openings  on  the  border  of  the 
disk). 

2.  Group  Ehabdoidea. 
The  chambers  piled  one  on  another,  in  a  straight  or  slightly  curved  line,  in  a  single  row. 

Fam,  9.  Nodosarida. — Eod-shaped  shells,  whose  chambers  are  superimposed  one  upon 
another  in  a  row,  and  communicate  with  each  other  by  a  large 
opening;  a  similar  opening  in  the  last  chamber  (except  in  the 
genus  ConuUna,  which  has  numerous  openings  instead  of  the  single 
one).  The  shell  visually  thick,  probably  always  perforated  by  fine 
pore-canals. 
Gen.  Glandulina,  Nodosaria,  Orthocerina,  Dentalina,  Frondicularia,  Lin- 
gulina,  Rimulina,  Vaginulina,  Webbina,  Conulina. 

3.    Group  SOROIDEA. 

Chambers  grouped  in  irregvdar  masses. 

Fam.  10.  AcERVULiNiDA. — Chambers  usually  globose,  disposed  very  irregularly,  and  of 
pretty  uniform  dimensions ;  shell  finely  perforate,  with  a  few  larger 
openings  at.  indeterminate  places. 
Gen.  Acervulina. 

The  preceding  account  of  the  Ehizopoda  we  believe  to  be  ample  to  lead  the 
student  forward  in  the  study  of  that  peculiar  class  of  animals.  Yet,  with  re- 
spect to  the  division  Foraminifera  it  may  be  considered  less  complete :  for, 
from  the  close  attention  given  of  late  to  those  beings,  every  monthly  and 
quarterly  periodical  of  natural  science  teems  with  fresh  facts  and  opinions 
concerning  them  ;  and,  above  all,  we  have  had  placed  in  our  hands,  since  the 
foregoing  history  was  written,  the  very  elaborate  and  critical  researches  of 


OF  THE  PROTOZOA. ACTINOPHRYINA.  243 

Prof.  Williamson  and  Dr.  Carpenter,  to  which  we  would  particularly  refer 
the  inquirer  intent  on  following  out  his  knowledge  of  the  Foraminifera,  but 
which  both  the  dimensions  and  the  character  of  the  present  work  forbid  the 
attempt  to  condense  or  analyse  in  its  pages.  Prof.  "Williamson's  work, '  On  the 
Recent  Foraminifera  of  Great  Britain/  forms  the  volume  for  1857,  published 
by  the  Ray  Society.  Dr.  Carpenter's  learned  essays  on  the  structure  of 
shells,  on  the  value  of  form  and  other  external  characters  in  generic  and  spe- 
cific groupings,  and  on  the  structural  and  physiological  relations  of  several 
genera,  are  to  be  found  in  the  '  Transactions '  and  in  the  '  Proceedings  '  of 
the  Royal  Society. 

Additional  facts  concerning  both  the  structure  and  relations  of  the  several 
groups  of  Rhizopoda  will  be  found  in  our  Systematic  History  of  them  in  Part  II. 


SUBFAMILY  OF  RHIZOPODA,  ACTINOPHRYINA. 
(Plate  XXIII.  24-37.) 

This  is  a  remarkable  group  of  Protozoa,  which  can  take  its  place  neither 
with  Ciliata  nor  strictly  with  Rhizopoda,  although  its  affinities  with  the  latter 
are  very  close.  Ehrenberg  attached  the  several  forms  of  this  family  with 
which  he  was  acquainted  to  his  heterogeneous  collection — the  famil^^  Enchelia, 
and  referred  them  to  five  genera,  viz.  Actinophrys,  TricJiodiseus,  Podophrya, 
Dendrosoma,  and  Acineta.  Moreover,  according  to  liis  fundamental  hypothesis, 
he  represented  them  to  have  a  mouth  and  an  anus,  an  alimentary  canal  with 
ofi'shoots  in  the  shape  of  stomach-vesicles,  a  sexual  gland,  and  ova.  Since 
the  Berlin  professor's  investigation  of  these  animalcules  was  made,  several 
distinguished  natm^alists  have  most  carefully  studied  them,  and  particularly 
the  Actinophrys  Sol. 

In  oui'  last  edition  we  named  a  genus  Alderia,  in  honour  of  Prof.  Alder,  to 
distinguish  certain  organisms  described  by  him  in  the  Annals  of  Natural  His- 
tory (1851,  vii.  p.  427).  Subsequently,  however,  that  eminent  natui^alist  wrote 
us  to  state  that  the  name  proposed  had  been  abeady  applied  to  a  genus  in  an- 
other class  of  animals ;  and  on  fiu-ther  consideration  and  reference  to  Stein's 
researches,  we  were  inclined  to  renounce  their  claim  to  a  generic  independ- 
ence, and  to  consider  them  three  forms  of  Podophrya.  Dr.  S.  Wright  has, 
however,  apparently  observed  the  same  beings  very  lately,  and  instituted  a 
new  genus,  EpJielota,  to  receive  them  {Edinb.  New  Phil.  Journ.  1858,  p.  6). 

Notwithstanding  the  very  close  affinities  of  Actinophryma  and  Acinetina, 
there  are  sufficient  differences  between  the  two,  and  so  many  peculiar  forms  of 
the  latter  that  they  deserve  a  particular  consideration. 

The  history  of  the  first  family  is  very  fairly  represented  by  that  of  Actino- 
phrys Sol,  or  of  Act.  Eichornii,  both  of  which  have  been  very  completely 
studied  by  Siebold,  KoUiker,  Claparede,  Stein,  and  Weston.  Some  diversity 
prevails  among  these  several  observers  respecting  a  few  points  in  their  organ- 
ization, which  it  wiU  be  incumbent  on  us  to  notice  in  the  proper  place.  The 
species  of  Actinophrys  have  a  circular  figure,  and  are  either  spherical  or  so 
compressed  as  to  have  a  discoid  form  (XXIII.  28,  29).  The  distinctive 
peuliarity  of  their  figure  is,  however,  due  to  the  filaments  or  tentacles,  which 
radiate  from  aU  parts  of  their  surface  and  give  the  beings  (to  employ  a 
familiar  and  not  inapt  illustration)  the  appearance  of  a  ball  of  cotton  stuck 
thickly  over  with  pins ;  for  the  filaments  have  nodular  extremities,  or,  in 
technical  phrase,  are  capitate.  The  figure  is  determinate,  and  in  this  respect 
contrasts  with  the  protean  changes  of  form  exhibited  by  Rhizopoda.  Not 
that  the  figure  is  completely  unalterable  ;  for  slight  variations  are  possible. 

r2 


244  GENERAL  HISTORY  OF  THE  INFUSORIA. 

although  slower  than  even  those  of  Amoeba.  Stein  represents  the  usual  orbi- 
cular figiu'e  to  be  frequently  exchanged  for  a  pear-shaped,  an  oblong,  or  a 
partially  angular  and  lobed  one, — varieties  dependent,  according  to  his  state- 
ments, upon  inherent  changes  taking  place  in  connexion  with  progressive  de- 
velopmental phenomena.  The  aspect  of  the  entire  organism  is,  moreover, 
modified  from  time  to  time,  by  the  altered  length,  direction,  and  disappear- 
ance of  a  portion  of  the  filaments,  chiefly  consequent  on  the  act  of  prehension 
in  which  they  are  engaged.  Stein,  indeed,  represents  still  more  considerable 
modifications,  involving  the  complete  disappearance  of  tentacles  from  various 
portions  of  the  surface,  and  the  aggregation  of  the  rest  upon  angular  emi- 
nences in  a  penicillate  manner, — an  occurrence  which  would  assimilate  still 
more  closely  the  Actiiiojyhryina  and  the  Ac'inetina.  Lastly,  the  figure  is  varied 
durmg  the  acts  of  self-division  and  of  conjugation,  as  will  be  presently  noticed 
at  large. 

In  coloiu'  the  Actinopliryina  are  commonly  of  a  milky-yellow  or  greyish 
hue,  the  intensity  of  which  is  determined  by  the  number  of  contained  granules, 
or,  in  other  vvords,  by  the  supply  of  nutriment.  Acetic  acid  and  cold  solution 
of  potash  remove  colour  ;  the  latter  fluid,  when  heated  rapidly,  dissolves  the 
entire  mass,  and  indicates  its  nitrogenous  natiu^e.  Observers  are  not  agreed 
on  the  point  of  the  existence  of  an  integment.  Dujardin,  Xolliker,  and  Cla- 
parede  deny  it,  whilst  Stein,  Perty,  and  Mr.  Weston  {J.  M.  S.  1856)  affirm  its 
presence.  Among  the  latter,  one  speaks  of  it  as  a  hyaloid  membrane ;  another 
declares  it  to  be  double,  consisting  of  a  delicate  elastic  membrane  immediately 
investing  the  contractile  substance  of  the  animalcules,  covered  by  an  outer 
fii^mer  timic.  This  statement  is  especially  made  by  Stein  of  Podophrya,  which 
is,  in  his  opinion,  a  merely  stalked  variety  oi  Actino_phrys,  and  indistinguishable 
from  it  even  as  a  species  (XXIII.  1,  3,  4,  5).  On  the  contrary,  Cienkowsky 
(J.  M.  S.  1857,  p.  98)  remarks  that  he  could  discover  no  membrane  surroimd- 
ing  the  body  of  that  animalcule.  To  account  for  this  diversity  in  descriptive 
details,  we  must  suppose  that  the  different  authors  have  not  had  the  same 
animalcule  under  observation  ;  indeed  Stein  asserts  that  Kolliker  did  not 
examine  Actinophrys  Sol,  as  he  supposed,  but  Act.  Eichornii.  Lieberkuhn 
likewise  suggests  that  Claparede  and  Kolliker  have  written  upon  difi'erent 
species  under  the  same  name ;  and  Stein  must,  we  beheve,  have  committed 
a  similar  mistake  ;  for  the  Actinophrys  and  Podophrya  described  by  him  difter 
in  so  many  important  particulars  from  beings  bearing  the  same  name  in  the 
writings  of  others,  that  it  seems  impossible  they  can  be  identical  with  them. 
The  fact  seems  to  be  that  certain  Acinetoi  have  in  external  characters  so  close 
resemblance  to  Act inophryma,  thai  they  may  be  mistaken  for  them.  Be  this  how 
it  may,  if  we  take  into  consideration  the  pecuhar  relation  of  the  tentacles  with 
the  body,  their  movements,  and  especially  the  mode  of  introducing  food  into 
the  interior,  it  seems  quite  improbable  that  there  should  be  a  firm  investing 
membrane.  These  remarks,  indeed,  apply  only  to  the  usual  forms  or  phases 
of  these  beings ;  for  when  an  encysting  process  proceeds,  then,  certainly, 
an  external  envelope  mil  manifest  itself,  yet  not  without  the  sacrifice  of  the 
tentacula  and  of  the  ordinary  phenomena  of  vital  activity,  the  ingestion  of 
food  and  the  like.  "  It  is  impossible,"  to  quote  Claparede  {A.  N.  H.  1855,  xv. 
p.  286),  "  to  admit  the  existence  of  a  general  integument,  as  Actinophrys  can 
push  out  the  mucous  or  gelatinous  matter  of  which  its  body  is  composed,  take 
in  nourishment,  or  evacuate  the  residue  of  digestion,  from  any  point  of  its 
surface  at  pleasure."  In  this  same  observer's  opinion,  Perty's  notice  and 
figures  of  a  capsule  are  evidently  erroneous,  the  consequence  of  optical  illu- 
sion. Mr.  Carter  adopts  an  intermediate  opinion,  by  admitting  the  existence 
of  an  enveloping  pellicula,  like  that  in  Amoeba,  which,  although  not  a  separable 


OF  THE  PROTOZOA. ACTINOPHRYINA.  245 

layer  or  skin,  is  a  somewhat  iirmer  or  more  condensed  tissue  than  that  sub- 
jacent. 

The  Actinophryina  are  composed  of  a  homogeneous  elastic  sarcode,  occupied 
by  granules  in  varying  number,  and  by  vacuolae.  The  granules  are  especially 
accumulated  in  the  centre,  to  wliich  they  consequently  impart  a  greater  opacity 
and  deeper  colour.  Hence  several  authors  have  spoken  of  a  central  medullary 
mass  surroimded  by  a  clearer  cortical  lamina  (XXIII.  28,  29).  Still  there 
is  no  natural  separability  into  two  such  portions ;  for  their  relative  size  varies 
according  to  the  supply  of  food  received.  Dr.  Strethill  Wright  (in  a  letter) 
proposes  to  apply  the  unexceptionable  terms  "  endosarc  "  and  "  ectosarc  "  to 
the  medullary  and  cortical  portions  respectively.  The  contained  granules  are 
rounded,  opaque,  and,  for  the  most  part,  of  a  fatty  character.  The  granules 
are  less  abundant  in  the  ectosarc ;  but  those  of  a  finer  sort  are  seen  in  smaller 
numbers  even  in  the  lower  end  of  the  filaments,  and  Lachmann  (A.  N.  H. 
1857,  xix.  p.  223)  asserts  that  he  has  seen  their  motion  there,  as  well  as  in 
the  general  substance  of  the  body.  Mr.  Weston  also  remarks  {op.  cit.  p.  122), 
*'  With  a  -i-th  objective  I  can  distinctly  see  granules  in  constant  motion  in  the 
body  of  the  ActinopJirys,  similar  to  those  always  found  in  the  points  of  Clos- 
terium  Lunula.''''  The  vacuoles  occur  both  in  the  cortical  and  medullary 
portions,  but  are  smaller  in  the  latter,  and  they  never  penetrate  into  the 
substance  of  the  filaments. 

At  first  sight,  as  Kolhker  notices,  the  tissue  appears  delicately  ceUular :  a 
closer  inspection,  however,  shows  that  this  is  not  the  case  ;  for  on  pressure 
being  made,  a  coalescence  into  larger,  or,  otherwise,  a  subdivision  into  smaller, 
areolae  is  the  consequence  (XXIII.  28,  29,  30). 

The  tentacles  or  filaments  give  to  the  Actinophryina  their  most  distinctive 
features.  They  are  usually  pretty  regularly  and  uniformly  distributed  over 
the  entire  surface,  and  in  figure  taper  from  the  base  to  the  apex,  which  is 
sui^mounted  by  a  rounded  knob.  Unlike  other  observers,  Cienkowsky  {J.  M.  S. 
1857,  p.  101)  represents  the  capitate  form  to  be  exceptional,  and  that  the 
rule  is  for  the  filaments  to  taper  like  setae.  Dujardin,  by  the  way,  appears  to 
have  thought  the  capitate  extremities  accidental ;  for  he  describes  the  filaments 
as  often  becoming  globular  in  the  act  of  contraction.  In  smaller  specimens 
the  filaments  exceed  the  diameter  of  the  body  in  the  length,  but  in  larger 
ones  are  not  more  than  equal  to,  or  are  even  less  than,  it.  In  the  same 
species  their  number  and  position  are  tolerably  constant.  In  composition, 
the  tentacula  are  processes  given  off  from  the  sarcode  mass,  and  are  destitute 
of  an  integument,  as  proved  by  their  power  of  coalescence  when  approximated. 
They  are  retractile,  and  can  be  withdi^awn  into  the  common  mass  ;  they  can 
also  be  dii-ected  towards  dififerent  sides,  and  curved  upon  themselves.  Perty 
states  that  they  can  assume  so  rigid  a  condition  that  other  animalcules  some- 
times impale  themselves  upon  them  ;  this  statement  is  nevertheless  uncon- 
firmed, and,  indeed,  seems  scarcely  probable.  KoUiker  (op.  cit.  p.  31)  speaks 
of  the  filaments  as  undergoing  various  changes  of  form,  '"  such  as  elongation, 

shortening,  local  sweUing,  bending,  &c It  is  especially  interesting  to 

observe  that  the  filaments,  singly  or  together,  frequently  disappear  entirely, 
entering  at  last,  as  it  were,  by  continued  retraction,  into  the  substance  of  the 
body,  leaving  no  trace  of  their  former  existence ....  whether  the  filaments 
which  disappear  are  always  reproduced  in  the  same  spot  is  not  determined ; 
i-n  some  instances  this  did  not  appear  to  be  the  case,  although  in  every 
instance  the  number  and  position  of  the  filaments  is  pretty  constant  " — unlike 
the  variable  processes  of  Amoeba.  Ehrenberg  assigned  to  the  tentacles, 
among  other  purposes,  that  of  organs  of  progression  ;  direct  observations  are, 
however,  wanting  to  prove  this  purpose,  and  both  KoUiker  and  Stein  are 


246  GENEEAL  HISTORY  OF  THE  INFrSOEIA. 

quite  unable  to  admit  it  as  even  probable.  They  have  been  supposed  by- 
several  authors  to  have  a  benumbing  effect  upon  the  prey  they  may  seize ; 
but  this  view  is  merely  hypothetical.  ''  It  is  nevertheless,"  says  Claparede 
{ojp.  cit.  p.  287),  "  quite  certain  that  small  animalcules  and  plants  remain 
adherent  to  them  ;  for  these  rays  are  true  tentacles.  Indeed,  their  contact 
must  have  something  very  unpleasant  about  it ;  for  larger  Infusoria,  even 
such  as  Paramecium  Aurelia,  on  coming  accidentally  within  their  reach,  start 
back  with  the  greatest  rapidity,  sometimes  even  dragging  the  Actinophrys  a 
considerable  distance  with  them."  So,  again,  Weston  states — ''  on  the  instant 
of  contact  with  these  tentacles,  the  victim  appears  paralysed."  Yet,  withal, 
it  seems  clear  that,  unless  actual  contact  ensue,  no  harm  attends  proximity 
to  the  formidable  prehensile  organs ;  for  animalcules  may  frequently  be  seen 
swimming  about  unharmed  among  them.  Kolliker  rejected  the  supposition 
of  an  intrinsic  fatal  influence  existing  in  the  filaments,  wliich  appeared  to 
him  to  serve  only  for  retaining  the  prey  by  their  adhesive  surface,  and  pro- 
bably to  involve  it  with  their  extremely  fine  extremities,  until  they  di-ew  it 
by  their  progressive  contraction  to  the  surface.  Even  after  being  seized  upon, 
an  animalcule  may  escape,  both  by  great  exertions  in  tearing  itself  away,  and 
sometimes,  as  Mr.  Weston  remarks,  by  the  act  of  the  ActhiopTirys,  when,  as 
it  Avould  seem,  its  appetite  was  "  sated,  or  the  prisoner  was  not  approved ; 
for  after  remaining  stunned  sometimes  for  a  few  seconds,  four  or  five,  some- 
times much  longer,  ciliary  motion  (of  a  Vorticella,  for  instance)  is  feebly  com- 
menced, not  ^^ith  sufiicient  energy  to  produce  motion,  but  as  if  a  return  to 
vitality  were  being  effected  by  struggles ;  shortly  it  is  seen  to  glide  off  the 
tentacle  (as  if  this  appendage  possessed  the  power  both  of  appropriation  and 
rejection),  and,  frequently  with  but  little  sign  of  recovered  life,  it  slowly  floats 
out  of  the  field."  One  function  distinctly  possessed  by  these  tentacula  is 
that  of  sensibility.  KoUiker  has  thus  well  conveyed  this  fact  {op.  cit.  p.  33) : 
— "Actinoj)h'i/s  perceives  mechanical  influences,  and  reacts  upon  them  by 
movements.  This  is  proved  by  what  takes  place  when  animalcules,  &c. 
remain  aflixed  to  its  tentacles,  and  moreover  by  the  circumstance  that,  when 
the  water  in  which  it  is  contained  is  carelessly  agitated,  every  ActinopJirys 
contracts  its  tentacles  and  even  makes  them  disappear  altogether  (and, 
indeed,  with  greater  speed  than  is  otherwise  perceived  in  these  creatures), 
and  when  all  is  quiet  they  are  again  protruded.  These  filaments,  conse- 
quently, may  just  as  well  be  called  tactile  as  prehensile ;  or  it  may  more 
generally  be  said,  that  the  substance  of  the  body  is  both  contractile  and 
sensitive." 

Movements. — There  is  not  much  to  be  said  respecting  the  movements  of 
the  Actinophryina ;  for  these  beings  are  even  more  sluggish  than  the  Amcebcea, 
and  appear  to  change  place  rather  as  mere  passive  particles  of  matter  than  as 
living  animals.  They  may  float  hither  and  thither  in  the  fluid  surrounding 
them,  or  rise  to  the  sm-face ;  but  how  this  latter  movement  is  effected  we  have 
no  data  to  show.  On  this  subject  KoUiker  has  the  following  paragraph : — 
"  Its  power  of  moving  from  place  to  place  is  indubitable  ;  for  it  was  found,  for 
instance,  that  when  a  vessel,  with  several  individuals  of  Actinophrys,  was 
emptied  into  a  flat  glass  capsule,  they  were  all  at  flrst  scattered  about  at  the 
bottom,  but  subsequently,  after  from  12  to  24  hoiu's,  were  all  floating  at  the 
surface,  and,  indeed,  at  the  side  of  the  capsule.  Ehrenberg  and  Eichhom 
assert  that  the  ascension  of  Actinophrys  in  the  water  is  effected  by  the  taking 
in,  and  the  descent  by  the  gi\ing  out,  of  air.  But  this  is  certainly  not  the 
case  ;  for  whence  could  they  obtain  this  air  ?  Can  it  be  said  they  secrete  it 
within  themselves  like  fishes  ?  In  that  case  it  must  be  visible.  It  appears 
to  the  author  more  natural  that  the  rising  and  sinking  should  be  effected  by 


OF  THE  PROTOZOA. ACTINOPHRYINA.  247 

alternate  eontractions  and  expansions  of  the  whole  body.  Other  motions  can 
affect  both  the  filaments  and  the  body,  but  in  any  case  only  through  the 
slowest  possible  contractions."  Besides  these  ill-understood  translations 
from  place  to  place,  and  those  movements  chiefly  affecting  the  tentacles  in 
the  act  of  taking  in  food,  to  be  presently  noticed,  there  also  occur,  according 
to  Kolliker,  ^'  faint  indications  of  contraction,  such  as  slight  undulations  of 
the  border,  and  inconsiderable  quivering  motions  here  and  there.  The  creature 
also  seems  to  be  capable  of  altering  its  entire  form  to  a  certain  extent,  and  to 
be  able  to  expand  and  to  contract  itself  in  toto^  Stein  contradicts  these 
statements,  affirming  that  he  could  neither  observe  any  movement  in  the 
organic  mass,  nor  any  change  of  position,  whilst  Claj)arede,  on  the  other 
hand,  writes,  '^  nevertheless  the  animal,  in  its  ordinary  sun-like  form,  is  able 
to  move  slowly  in  a  given  direction ;  but  during  this  movement  no  contraction 
of  the  body  or  bending  of  the  tentacles  is  to  be  observed."  A  singular  obser- 
vation is  recorded  by  Mr.  Boswell  {T.  M.  S.  1854,  p.  25),  which  needs  con- 
firmation before  it  can  be  accepted,  viz.  that  the  Actinophryina  can  suddenly 
change  their  place  by  a  leap.  This  phenomenon,  he  tells  us,  he  witnessed 
twice  among  a  number  of  the  animalcules  found  floating  on  the  suiface  of  the 
water.  Usually  the  Actinophrys  is  found  attached  to  some  object,  and  that 
so  firmly  that  large  animalcules  may  strike  against  it,  or  strong  succussions 
of  the  water  take  place  without  loosening  it  from  its  hold.  Podoplwya  and 
Demh'osoma  are  exceptional  Actinopliryina,  by  possessing  a  pedicle.  In  the 
former  this  stem  is  commonly  short  and  always  simple,  whilst  in  the  latter 
and  hitherio  little-known  genus  it  is  branched.  As  elsewhere  noticed,  Stein 
will  not  admit  the  pedicle  of  Podophrya  to  be  a  generic,  indeed  not  even  a 
specific,  distinction,  and  therefore  treats  Actinophrys  and  Podophrya  as 
identical.  In  connexion  with  his  belief  in  the  presence  of  an  enclosing 
integument,  he  describes  the  wall  of  the  hoUow  pedicle  of  Podophrya  to  be 
continuous  upwards  with  the  external  envelope  of  the  body  (XXIII.  3,  4). 
It  is  proper,  however,  to  remember  that  Stein  wanted  both  to  establish  his 
hypothesis  of  the  conversion  of  Vorticella  into  an  Actinophrys  and  Podophrya, 
as  a  consequence  of  the  act  of  encysting,  and  preparatory  to  embryonic  repro- 
duction, and,  further,  to  assimilate  those  genera  with  various  Acinetce,  which, 
in  his  opinion,  were  derivable  from  other  members  of  VortlceTlina.  This 
detracts  from  the  value  of  his  details  of  the  structure  and  functions  of  Actino- 
phrys ;  and,  as  expressed  above,  a  great  doubt  suggests  itself  whether  he  has 
always  examined  the  selfsame  animalcules,  and  whether  what  he  has  de- 
scribed applies  to  the  Actinophrys  investigated  by  Kolliker  and  Claparede. 
Cienkowsky,  who  has  latterly  tested  Stein's  hypothesis,  asserts,  respecting 
the  question  of  the  structure  of  the  stem  of  Podophrya,  that  the  pedicle  is 
an  appendage  to  the  body,  which  has  no  integument.  "  I  am  unable  "  (op. 
cit.  p.  100),  he  writes,  "  to  adopt  Stein's  view  that  the  Podophrya  are  enclosed 
in  a  membrane,  of  which  the  slender  pedicle  is  simply  a  tubular  protrusion. 
This  is  true  only  with  respect  to  the  short  peduncle  of  the  encysted  Podophrya  " 
(XXIII.  36,  37). 

Prehension  and  Entrance  of  Food. — The  movements  of  the  tentacula  of 
Actinophryina  are  chiefly  directed  to  the  prehension  of  prey  for  food.  This 
they  eff'ect  primarily  by  seizing  it  by  means  of  their  apparently  sticky  surface, 
and  then,  by  shortening  themselves,  drag  it  to  the  surface  of  the  animalcule. 
If  the  prey  has  been  caught  by  one  tentacle,  the  neighbouring  ones  conspire  to 
clutch  it  more  firmly,  and  (to  use  Kolliker's  words)  "  apply  themselves  upon 
it,  bending  their  points  together,  so  that  the  captive  becomes  gradually  en- 
closed on  aU  sides."  This  concui'rence  and  crossing  of  the  tentacles  is  men- 
tioned also  by  Stein  ;  but  Mr.  Weston  states  that  he  has  never  witnessed  it. 


248 


GENEKAL  HISTORY  OF  THE  INFUSORIA. 


Concerning  the  mode  of  entrance  of  the  nutritive  matter  when  di'awn  to  the 
surface,  some  difference  of  opinion  prevails  among  the  several  writers  who 
have  treated  of  it.  Ehrenberg,  true  to  his  hypothesis,  attributed  to  Actino- 
phri/ina  a  mouth  sui^mounted  by  a  proboscis,  and  an  anus  at  the  opposite  side 
Avith  an  intercommunicating  intestine  and  numerous  stomach-sacs  opening 
into  it.  In  short,  they  were,  according  to  his  scheme  of  organization, 
Enantiotreta,  of  the  class  Enterodela.  Dujardin  rejected  this  account,  and 
supposed  them  to  be  nomished  by  absorption,  carried  on  by  the  general 
siuface,  or  by  means  of  thick  expansions  from  it.  At  the  present  time  all 
observers  unite  in  denying  a  mouth,  anus,  and  alimentary  canal  to  Actino- 
phryina,  and  in  admitting  that  food  may  be  introduced,  and  its  debris  dis- 
charged, at  any  part  of  the  smf ace, — a  fact  patent  to  direct  observation,  which 
shows  the  seizing  and  the  entrance  of  prey  going  on,  occasionally,  at  more 
than  one  point  at  a  time  (XXIII.  29-32).  We  have  followed  the  captured 
morsel  until  it  apjDroaches  the  sui'face,  and  when  the  force  of  the  tentacles 
behind  it  still  tends  to  press  it  onwards  into  the  body.  The  following  pro- 
ceeding, according  to  Kolliker  {op.  cit.  p.  28),  now  takes  place : — "  The  spot 
of  the  sui'face,  upon  which  the  captured  animalcule  is  lying,  slowly  retracts 
and  forms  at  first  a  shallow  depression,  gradually  becoming  deeper  and  deeper, 
in  which  the  prey,  apparently  adherent  to  the  surface  and  following  it  in  its 
retraction,  is  finally  lodged  (XXIII.  29  m).  The  depression,  by  the  continued 
retraction  of  the  substance,  now  becomes  deeper  ;  the  imprisoned  animalcule, 
which  up  to  this  time  had  projected  from  the  surface  of  the  ActinophrySy 
disappears  entirely  Avithin  it ;  and  at  the  same  time  the  tentacles,  which  had 
remained  with  their  extremities  applied  to  each  other,  again  erect  themselves 
and  stretch  out  as  before.  Finally,  the  depression  acquii'es  a  flask-like  form, 
by  the  di^awing  in  of  its  margin,  the  edges  of  which  coalesce ;  and  thus  a 
cavity  closed  on  all  sides  is  formed,  in  which  the  prey  is  lodged.  In  this 
situation  it  remains  for  a  longer  or  shorter  time,  gradually,  however,  ap- 
proaching the  central  or  nuclear  portion,  and  at  last  passing  entirely  into  it 
in  order  to  await  its  final  destination.  In  the  meanwhile  the  external  por- 
tion of  the  Actinophrys  regains  in  all  respects  its  pristine  condition.  The 
engulfed  portion  is  gradually  digested  and  dissolved."  Whilst  admitting 
the  general  correctness  of  this  account  by  Kolliker  of  the  act  of  inglutition, 
Stein  asserts  that,  prior  to  the  appearance  of  the  prey  in  a  depression  of  the 
body,  a  large  vacuole,  rising  above  the  smface,  comes  into  contact  with  it,  and 
then,  by  its  collapse,  drags  it  downwards  into  the  substance  of  the  animalcule. 
This  stage  he  supposed  KoUiker  to  have  overlooked.  However,  Claparede 
denies  that  the  reception  of  food  is  ever  effected  by  means  of  the  expansion 
and  contraction  of  a  vesicle,  or  that,  as  Kollilier  believed,  the  food  penetrates 
the  substance  of  the  body  by  the  force  exercised  upon  it  behind  by  the 
tentacula :  it  is  rather,  he  says,  the  substance  of  the  body  which  approaches 
and  embraces  the  food ;  for  before  the  latter  has  touched  the  surface  of  the 
body,  it  is  seen  to  be  envelojDed  in  a  kind  of  mucus.  -'  This  mucus  is  com- 
pletely undistinguishable  from  the  parenchyma  of  the  Actinoplirys  ;  it  appears 
as  though  the  substance  of  which  it  is  composed  had  suddenly  drawn  itself 
over  the  captured  object.  The  elevation  thus  produced  then  slowly  flattens; 
and  by  this  means  the  food  is  gradually  di^awn  into  the  body.  Astasice,  which 
I  frequently  saw  sucked  in  by  Actinophrys  in  this  way,  continued  to  move 
for  a  Httle  time,  endeavouring  to  break  thi-ough  the  substance  that  enveloped 
them  ;  their  movements,  however,  soon  ceased  ;  they  became  converted  into 
a  globular  mass,  which  circulated  very  slowly  through  the  parenchyma  with 
the  so-called  vacuola." .  .  .  . "  At  fii'st  I  thought  the  substance,  which  so 
suddenly  enveloped  the   object  to  be  swallowed,  was  produced  by  the  mere 


OF  THE  PROTOZOA. ACTINOPHRYINA.  249 

bending,  expansion,  and  fission  of  the  tentacles.  I  could  not,  however, 
retain  this  opinion:  an  extension  of  a  mucons  substance,  apparently  the 
parench}Tna,  really  takes  place  from  the  side  of  the  Act'mo]phrys ;  and  this  is 
afterwards  drawn  in  with  the  prey.  This  expansion  sometimes  takes  place 
very  slowly  ;  a  thick,  regularly  lobed  mass  is  seen  to  embrace  the  object ; 
and  I  have  once  observed  this  extension  Avithout  the  presence  of  any  prey. 
I  can  only  compare  this  process  with  what  takes  place  in  Amoeba  ^  Dr. 
Strethill  AYright  (in  lit.)  expresses  the  same  fact  in  a  condensed  form, 
thus : — "  In  Actinophrys  the  tentacles  bring  the  food  to  the  sui-face  of  the 
ectosarc,  which  closes  over  it  and  cames  it  to  the  endosarc."  Mr.  Weston's 
observations  tend  to  a  similar  interpretation  of  the  mode  of  introduction  of 
food.  "  From  the  margin  of  the  body  of  the  Actinophrys,^^  says  this  gentle- 
man, "  a  thin  pellucid  membrane  is  projected  up  the  side  of  the  creatui'e 
destined  for  food  (XXIII.  24-32),  which  proceeds  rapidly,  but  almost 
imperceptibly,  to  siuTound  one  side  of  it ;  a  similar  membrane  sj)rings 
sometimes  also  from  the  Actinojplirys,  but  more  frequently  from  the  tentacle 
on  its  other  side ;  these  amalgamate  on  the  outer  surface  of  the  prisoner, 
which  is  thus  enclosed  in  a  sac  composed  of  what  I  take  to  be  the  extended 
outer  vesicle  of  the  Actinopjhrys.  This  vesicle  gradually  contracts,  or,  rather, 
seems  to  retiu-n  by  elasticity  to  its  original  position  ;  and  the  food  thus  be- 
comes pressed  within  the  body,  there  to  become  digested."  The  conclusion 
to  be  drawn  is,  that,  after  the  act  of  prehension  by  the  tentacles  is  complete, 
the  retraction  of  those  processes  is  succeeded  by  the  protrusion  of  a  sort  of 
variable  i^rocess,  similar  to  those  of  Amoeba  in  character,  and  also  in  its  mode 
of  enveloping  and  engulfing  the  morsel. 

After  its  admission  into  the  soft  substance  of  the  interior,  the  nutrient 
matter  undergoes  a  process  of  digestion,  by  which,  if  soft,  it  suffers  complete 
dissolution  and  absorption ;  but  if  it  contain  insoluble  matter,  this  remains 
behind,  after  the  disappearance  of  the  rest,  as  a  residue  to  be  sooner  or  later 
cast  out  through  an  apertiu-e  temporarily  formed  at  the  point  of  the  surface 
it  comes  into  contact  with,  and  of  which  aE.  trace  is  lost  so  soon  as  the  act  of 
extrusion  is  accomphshed.  The  molecular  and  granular  matters  derived  fi^om 
food  coUect  especially  in  the  central  or  nuclear  portion  of  the  body,  the  depth 
of  coloiu',  opacity,  and  strength  of  which  are  directly  proportionate  to  the 
supply  of  food.  The  particle  of  food  (the  animalcule  or  other  substance), 
when  in  the  interior,  is  surrounded  by  or  suspended  in  a  drop  of  fluid,  or,  in 
Dujardin's  phi^aseology,  occupies  a  vacuole.  This  fluid  is  either  di-awn  in 
by  the  act  of  inglutition,  or  is  a  secretion  pom-ed  out  around  the  food  for  the 
pm-pose  of  digestion.  Claparede  takes  the  latter  view,  and  states  that  the  fluid 
always  exhibits  the  same  pale-reddish  colour  as  the  contents  of  the  contractile 
vesicle,  and  indicates  different  refractive  powers  from  those  of  water.  This 
observation  accords  with  one  made  by  Sclmeider,  of  the  digestive  vacuoles  of 
Amoeba. 

The  process  of  digestion  is  slow.  Claparede  observed  the  changes  of  a 
Chlamydomonas,  and  states  that  three  hours  scarcely  sufficed  for  its  conver- 
sion into  an  unrecognizable  gelatinous  mass.  KoUiker  represents  the  time  to 
vaiy  from  two  to  six  hom^s ;  but  this  must  differ  jDerpetuaUy  according  to  the 
nature  of  the  food,  the  \itality  of  the  animal,  &c.  ''  The  number,  as  well  as  the 
size,"  writes  Kolliker,  "  of  the  morsels  taken  at  one  time  by  the  Actinojyhrys 
is  very  various.  Yeiy  frequently  there  may  be  2,  4,  or  6  at  the  same  time, 
frequently  also  more  than  10  or  12.  Ehrenberg  counted  as  many  as  16 
stomachs,  i.  e.  in  other  words,  so  many  separate  morsels.  He  also  noticed  the 
ingestion  of  indigo,  which  could  not  have  gained  admission  in  any  other  way 
than  that  by  which  the  Infusoria  and  other  ahmcnts  enter.  The  largest  morsels 


250  GENERAL  HISTORY  OF  THE  INFUSORIA. 

noticed  consisted  of  a  Lynceus  and  a  young  Cyclops.  Eichhorn,  indeed, 
mentions  a  water-flea  {Daplinia  ?),  about  the  size  of  which,  however,  no  re- 
mark is  made."  Indeed,  the  Actinophryina  are  rapacious  animals,  and  will 
appropriate  to  themselves  any  organisms,  vegetable  or  animal,  which  fall  in 
their  way.  Thus,  besides  those  beings  alluded  to  already,  Eotifera,  various 
minute  Crustacea,  Cihated  Protozoa,  Phytozoa  of  all  sorts,  Desmidieae,  Dia- 
tomeae,  minute  Algae,  and  their  spores  ahke  fall  a  prey  to  these  remarkable 
animalcules.  The  excrementitious  particles  of  food,  as  already  stated,  pass 
out  at  any  spot  where  circumstances  may  dii-ect  them ;  and  no  definite  anal 
aperture,  such  as  Ehrenberg  imagined,  has  an  existence.  The  expulsion  of  re- 
sidual matters,  Mr.  "Weston  {J.  M.  S.  1856,  p.  121)  states  he  has  "  fi'equently 
seen, — in  one  specimen  twice  in  less  than  half  an  hour,  at  diiferent  spots.  In 
watching  the  digestion  of  a  Rotifer,  it  occurred  to  me  to  see  a  dark  body, 
composed  apparently  of  the  case,  remain  for  some  hours  in  the  same  spot, 
and  then  gradually  approach  the  side,  as  if  for  expulsion ;  but  while  waiting 
for  this  to  take  place,  an  opening  in  another  part  occuiTed,  and  excrement 
was  voided  in  quantity :  this  voided  matter  lies  amongst  the  bases  of  the 
tentacles,  while  the  opening  through  which  it  has  passed  closes ;  and  then, 
with  the  same  stealthy  motion  I  have  before  described,  it  is  apparently  diiven 
along  the  tentacles  (as  if  by  repulsion)  beyond  their  extremities,  finally  dis- 
appearing in  the  surrounding  medium." 

Contractile  vesicle. — The  rule  is,  that  only  one  contractile  vesicle  belongs 
to  each  animalcule  (XXIII.  36,  37).  If  more  appear,  it  usually  indicates 
either  the  approach  of  fission,  or  the  conjugation  of  two  or  more  individuals 
(XXIII.  33-35).  Kolliker  failed  to  recognize  this  organ  in  Actinophrys,  and 
concluded  that  Siebold  had  described  as  such  the  mere  changeable  vacuola. 
However,  Stein,  Claparede,  Cienkowsky,  and  others  concur  in  representing  a 
contractile  vesicle  as  normally  present ;  the  fii'st-named  writer,  indeed,  de- 
scribes in  a  few  instances  two  such,  as  Siebold  has  done  before  him.  Stein 
exhibits,  in  Actinophrys  Sol,  the  vesicle  as  central  (XXIII.  1) ;  but  other 
naturahsts  concur  in  representing  it  as  supei-ficial, — so  much  so,  according  to 
Siebold,  that  it  will  frequently  dming  its  expansion  project  above  the  general 
surface,  and  thereby  prove  itself  to  have  a  distinct  wall  (XXIII.  29  m)  ;  for 
if  composed  of  only  the  gelatinous  parenchyma  of  the  body,  it  would  burst  at 
the  moment  of  greatest  expansion.  It  is,  therefore,  a  closed  sac  or  cell. 
Claparede  has  never  found  more  than  one  vesicle,  and  thinks  both  Siebold 
and  Stein  in  error  in  describing  two.  "  Several  vesicular  elevations,"  he 
writes,  "  often  occur  on  the  margin  ;  but  only  one  of  these  is  contractile.  I 
have,  however,  observed  two  contractile  vesicles  in  several  individuals ;  but 
in  these  cases  the  form  always  gives  rise  to  a  suspicion  of  fission,  or  of  an 
amalgamation  of  two  individuals  (Act.  clifformis,  Ehr.).  The  presence  of  a 
single  contractile  vesicle  does  not,  however,  appear  to  be  imiversal  among  the 
Rhizopoda ;  I  have  observed  two  in  Arcella  vulgaris ....  It  is  surprising  that 
Kolliker,  who  was  acquainted  with  Siebold's  observations,  should  have  cha- 
racterized them  as  inexact,  and  as  arising  fi'om  an  illusion.  According  to 
him,  Siebold  had  mistaken  accidental  expansions  and  contractions  of  the  sub- 
stance enclosing  the  vacuoles,  in  which  the  latter  were  persistent,  for  phe- 
nomena indicating  the  existence  of  contractile  reservoirs.  This,  however,  is 
not  the  case ;  the  size,  the  unchanging  position,  and  the  regular  expansion 
and  contraction  of  this  organ  will  prevent  its  being  confounded  with  a 
vacuole.  That  KoUiker  should  have  overlooked  it  is  particularly  iminteUigi- 
ble,  as  the  phenomenon  is  immediately  presented  by  nine  out  of  ten  specimens 
of  Actinophrys.''^ 

Carter  {A.  N.  H.  xviii.  p.  129)  makes  the  curious  assertion,  that  the  '^Actino- 


OF  THE  PROTOZOA. ACTINOPHHYINA.  '    251 

■phrys  Sol,  Ehr.,  is  siuTounded  by  a  perii^heral  layer  of  vesicles  "  (he  is  speaking 
of  contractile  vesicles),  "  which,  when  fully  dilated,  appear  to  be  all  of  the 
same  size,  to  have  the  power  of  communicating  with  each  other,  and  each, 
individually,  to  contract  and  discharge  its  contents  externally,  as  occasion  may 
require,  though  generally  only  one  appears,  and  disappears,  in  the  same 
place."  Stein  describes  and  figures  a  row  of  vesicles  immediately  beneath 
the  surface  of  a  new  species  he  calls  Actinojphrys  oculata  (XXIII.  24,  25), 
but  does  not,  hke  Carter,  treat  them  as  so  many  contractile  sacs,  an  interpre- 
tation which  cannot  be  received  without  much  more  extended  inquiiy  and 
confii-mation.  Notwithstanding  this  assertion,  Mr.  Carter,  in  his  outline  of 
facts  relevant  to  contractile  vesicles  in  general,  has  the  following  clause,  ap- 
plying specially  to  the  animalcules  under  consideration,  and  giving  a  most 
apt  illustration  of  the  phenomena  witnessed : — "  In  Actinophrys  Sol,  and 
other  Amcehce,  diuing  the  act  of  dilatation,  the  vesicula  projects  far  above  the 
level  of  the  pellicula,  even  so  much  so  as  occasionally  to  form  an  elongated, 
transparent,  mammilliform  eminence,  which,  at  the  moment  of  contraction, 
subsides  precisely  like  a  blister  of  some  soft  tenacious  substance  that  has  just 
been  pricked  with  a  pin."  At  another  part,  this  same  author  says,  generally 
(op.  cit.  p.  128),  and  in  some  measure  contradictoiily  to  the  first  statement 
quoted  from  him,  that  "in  Amceha  and  Actinoplirys  the  vesicula  is  generally 
single  ;  sometimes  there  are  two,  and  not  unfrequently  in  larger  Amoebcea  a 
greater  number."  It  should  be  mentioned  that  Stein  found  in  the  animal- 
cule, which  he  took  to  be  Act.  Eiclioy^nii,  a  superficial  group  of  vacuola,  ren- 
dering the  outline  irregiilar, — a  phenomenon  no  doubt  the  same  as  that 
intended  by  Carter.  Stein,  moreover,  described  in  the  same  animalcule  two 
contractile  spaces,  one  at  each  pole,  immediately  beneath  the  surface,  but 
capable  of  alternately  elevating  themselves  above,  and  depressing  themselves 
within  it,  and  of  thereby  aiding  to  introduce  food. 

Podophi^ya  has,  according  to  Stein  and  Cienkowsky  (XXIII.  34,  35,  36, 
37),  a  single  circular  contractile  vesicle.  Stein,  indeed,  figures  two  in  one 
specimen.  So  far  as  appears,  the  vesicle  is  not  placed  so  close  to  the  surface 
as  in  Actinophrys.  Among  other  structui'es  mentioned  by  Ehrenberg,  was  a 
contractile  proboscis,  by  means  of  which  the  animalcule  was  supposed  to  re- 
ceive food ;  but  other  observ^ers  have  looked  in  vain  for  any  process  to  which 
such  an  appellation  could  with  justice  be  apphed.  The  structure  intended 
by  Ehi'enberg  is,  in  Claparede's  opinion,  no  other  than  the  contractile  vesicle, 
— an  opinion  in  which  Mr.  Weston  seems  to  agree  (see  below),  although  he 
attributes  to  it  a  structure  and  action  without  parallel  in  other  Infusoria.  A 
glance  at  the  quotation  above  made  from  Mr.  Carter's  paper  will  show  also 
that  the  contractile  sac  was  intended.  The  following  are  the  observations  of 
Claparede,  referring  to  the  matter  in  question: — *Trom  time  to  time  a  globular 
prominence  rises  slowly  and  gradually  from  a  particular  point  on  the  surface 
of  the  animal ;  this  increases  more  or  less  in  difi'erent  cases,  sometimes,  espe- 
cially in  small  individuals,  attaining  nearly  a  thii^l  of  the  size  of  the  entire 
body,  but  generally  reaching  only  -i-th  or  ^ij-th  of  that  size.  The  margin  of 
this  projection  is  always  well  defined,  much  more  so  than  the  other  parts  of 
the  body,  especially  when  it  has  attained  its  greatest  evolution.  At  this 
moment  it  contracts  suddenly  and  disappears  entirely,  so  that  a  flattening  of 
the  outline  is  often  to  be  observed  at  the  point  previously  occupied  by  this 
remarkable  elevation  :  the  margin  soon  becomes  rounded  again ;  the  globular 
projection  gradually  rises,  attains  its  previous  highest  development,  and  then 
suddenly  disappears  again."  The  following  paragraph  from  Mr.  Weston's 
paper  {J,  M.  S.  1856,  p.  116)  refers,  doubtless,  to  the  selfsame  expanding  and 
contracting  process  distinguished  by  Claparede  :  but  the  fimction  of  respiration 


252  GENERAL  HISTORY  OF  THE  INFUSORIA. 

and  a  valvular  structure  of  a  very  extraordinary  natui'e  are  attributed  to  it. 
We  suspect,  indeed,  that  Mr.  Weston  has  been  led  into  error  by  appearances, 
— a  supposition  he  will  pardon  us  for  making,  since,  as  he  himself  tells  us,  his 
microscopic  experience  is  less  than  two  years  old.  His  account  runs  thus : — 
"  There  appears  to  be  no  doubt  about  the  existence  of  a  valvular  opening  :  I 
have  had  some  thousands  of  these  animalcules  under  my  observation,  and 
have  never  met  mth  a  specimen  where  the  valve  was  absent.  It  is  best 
distinguished  when  about  the  edge  of  the  seeming  disc,  and,  so  far  as  my 
observations  go,  is  never  still  night  nor  day, — being  slowly,  but  without  cessa- 
tion, as  it  were,  protruded,  occupying  from  10  to  70  or  80  seconds  in  its 
development,  and  then,  like  the  bursting  of  a  vesicle,  rapidly  and  totally 
subsiding ;  for  an  instant  it  has  utterly  disappeared,  only  to  be  again  as 
gradually  and  as  certainly  reproduced.  Should  that  side  of  the  creature, 
where  the  valve  is  placed,  be  tiu-ned  from  the  observer,  the  effects  of  the 
contraction  are  distinctly  seen,  although  the  valve  itself  is  not ;  for  at  the 
instant  of  its  bursting  and  closure,  some  half-a-dozen  or  more  of  the  tenta- 
cles, situated  on  or  about  it,  which  have  been  gradually  thrust  from  their 
normal  position  by  the  act  of  its  protrusion,  now  rapidly  approach  each  other 
with  a  jerk-Hke  motion,  caused  by  the  sudden  biinging  together  of  their 
bases. 

"  With  -i-th  of  an  inch  objective,  I  have  been  led  to  imagine  the  valve  to  be 
formed  of  a  double  layer  of  the  external  hyaloid  membrane,  the  edges  of 
which  appear  to  adhere  to  each  other  tenaciously,  notwithstanding  the 
growing  distension  from  within,  until  the  force  becomes  so  great  that  the 
lips,  as  they  may  be  called,  suddenly  separate,  apparently  to  give  vent  to 
some  gaseous  product ;  and  at  this  moment  there  is,  as  I  have  stated,  enough 
seen  to  induce  the  belief  in  the  existence  of  a  double  lip -like  valve,  perhaps 
the  organ  of  respiratioyi.''^ 

He  afterwards  adds  (p.  118) — "  In  many  instances  I  have  seen  half-a- 
dozen  or  more  prisoners  attracted  to  the  tentacles  of  an  individual,  each  gra- 
dually absorbed ;  and  although  thus  busily  occupied,  no  cessation  of  the  action 
of  the  valve  takes  place."  Stein  imagined  the  movements  of  the  contractile 
sac  to  be  subservient  to  the  reception  of  food ;  but  this  supposition,  as  men- 
tioned already  (p.  248),  is  opposed  to  analogy,  and  is  wanting  in  direct  obser- 
vation to  establish  it. 

Among  the  general  contents  of  the  body  of  Actinophrys,  Kolliker  (pp.  cit. 
p.  27)  mentions  some  separable  nuclear  cells  as  detached  by  crushing  from 
the  innermost  portions  of  the  animal.  When  isolated  by  pressure,  they  be- 
have themselves  as  cells,  with  nucleus  and  nucleolus,  sometimes  as  free 
nuclei.  "  The  author  is,  in  fact,  inchned  to  regard  them  as  cells  and  nuclei, 
Ipng  in  some  of  the  interior  vacuoles  ;  for  such,  and  such  only,  are  the  vesi- 
cular spaces  in  which  they  are  enclosed."  (XXIII.  29.) 

NucLErs. — Kolliker  applied  the  term  nucleus,  very  improperly,  to  the  more 
granular  and  darker  central  or  medullary  portion  of  the  body  (XXIII.  29  h), 
and  overlooked  the  presence  of  the  real  nucleus.  However,  Stein,  Carter, 
Cienkowsky,  and  others  have  determined  the  existence  of  this  organ  in  the 
genera  Actinophrys  and  Podophrya.  Unfortunately,  some  difference  prevails  in 
the  descriptions  of  this  organ  by  the  several  observers,  which  it  is  most  desirable 
to  have  removed.  Carter  {A.  N.  H.  1856,  x\iii.  p.  221)  represents  it  to  be  a 
cloudy  body,  "  discoid  in  shape,  of  a  faint  yellow  colour,  and  fixed  to  one  side 
of  a  transparent  capsule,  which,  being  generally  more  or  less  larger  than  the 
nucleus  itself,  causes  the  latter  to  appear  as  if  suiTounded  by  a  narrow  pel- 
lucid ring."  Stein  describes  it  in  Actinophrys  Sol  as  finely  granular,  band- 
shaped,  and  curved,  or  reniform,  or  rounded  oblong  (XXIII.   1  b).     Cien- 


OF  THE  PROTOZOA. ACTINOPHRYINA.  253 

kowsky  says  that  the  nucleus  of  PodopTirya  is  ^'  transverse  and  frequently 
curved,"  and  thereby  implies  that  it  is  an  elongated  body.  The  nucleus  of 
Actinojphrgs  oculata  (says  Stein,  p.  159)  may  be  brought  into  view  either  by 
crushing  the  animalcule,  or,  much  more  satisfactorily,  by  adding  dilute  acetic 
acid  (XXIII.  24  h,  25  g).  On  viemng  it  from  above,  it  appears  like  a  round 
hyaline  cell,  containing  a  granular  nuclear  mass  in  its  centre,  and  suiTounded 
by  a  rather  condensed  layer  of  the  medullary  matter.  On  its  entire  detachment, 
by  means  of  the  acid,  it  is  seen  to  possess  a  distinct  wall,  ha^i^ng  a  double  out- 
line ;  its  nucleolus,  on  the  contrary,  seems  undefined  and  irregular  in  shape, 
composed  of  a  mere  heap  of  fine  granules.  The  relative  size  of  the  nucleus 
to  the  whole  animal  is  veiy  considerable.  Thus,  whilst  the  majority  of  spe- 
cimens had  a  diameter  of  1-38  to  1-35'",  the  nucleus  measured  1-125'",  and 
its  nucleolus  1-250'".  From  his  account  of  Act.  EicJiomii,  Stein  would  appear 
to  have  seen  a  similar  nucleus  in  that  species ;  for  he  states  that  the  round 
nucleus  appeared  hke  a  nucleus-holding  cell,  having  a  double  contoui'  and 
clearly-defined  waU,  and  containing  a  large,  finely-granular  nucleolus. 

Encysting  and  Repeoductive  Processes  of  Actinophryina  : — Encysting — • 
Fission — Gemmation — Embryos — Conjugation. — Stein  represents  his  Acti- 
nophrys  Sol  and  Podophrya  fixa  as  having  a  double  integument  (XXIII.  1,  3), 
through  which  the  tentacles  penetrate, — whilst,  as  we  have  seen,  other  ob- 
servers insist  upon  the  naked  state  of  the  muco-gelatinous  body  of  those  as 
well  as  of  the  other  species  of  Actinophryina.  The  questions  therefore  arise, 
whether  the  being  so  named  and  described  by  Stein  is  identical  with  that  in- 
tended by  other  naturalists,  and,  if  so,  whether  it  is  not,  in  the  so-called 
encysted  condition,  at  least  in  its  earlier  stage.  For  Stein  subsequently 
describes  and  figures  truly  encysted  examples,  in  which  the  cyst  appears  like 
a  plicated  loose  sac  around  the  contracted  body,  and  the  tentacles  in  part  or 
wholly  gone  (XYIII.  3).  Cienkowski  afiirms  (0^3.  cit.  p.  101)  that  the  being 
described  as  Actinophrys  by  Ehrenberg  is  really  a  non-pedunculate  Acineta  ; 
and  he  further  remarks  that,  although  numerous  points  of  relation  exist 
between  certain  ^cme^a -forms  and  Poclophrya  flxa,h.e  is  unable  to  determine 
whether  they  should  be  regarded  as  identical,  or  as  the  extreme  links  in  the 
morphological  cycle  of  one  and  the  same  species.  The  same  critical  observer 
details  the  process  of  encysting  of  PoclopJirya, — a  process,  by  the  way,  which 
he  has  not  met  with  in  ^t-me^^-form  organisms  having  a  general  resemblance 
with  it.  To  quote  his  account  {op.  cit.  p.  99),  "  If  PodoplirycB  are  allowed 
to  remain  several  days  upon  the  object-glass,  and  care  is  taken  not  to  let  the 
water  diy  up,  eveiy  stage  towards  the  quiescent  condition — that  is  to  say, 
towards  the  '  encysting  ' — may  be  followed  (XXIII.  34,  36,  37). 

*'  In  Podophi^y  a  ihi^  process  takes  place  in  the  following  manner: — On  the 
surface  of  the  body  a  gelatinous  mucous  layer  appears  to  be  secreted,  through 
which  the  tentacles  pass.  The  tentacles  disappear  in  the  neighbourhood  of 
the  peduncle ;  and  the  gelatinous  layer  in  this  situation  hardens  into  a  loose 
transversely-plicated  membrane,  whilst  at  the  upper  end  it  is  still  soft,  and 
the^  tentacles  clearly  visible.  Ultimately  these  also  are  retracted,  and  the 
entire  body  of  the  Podophrya  is  enveloped  in  a  wide  loose  membrane ;  the 
plications  are  caused  by  parallel  annular  constrictions,  placed  at  equal  di- 
stances apart,  and  separated 'by  circular,  angular,  or  rounded  ridges ;  these  pli- 
cations are  in  a  plane  perpendicular  to  the  peduncle.  At  the  summit  of  the 
Podophrya,  and  often  also  at  the  base,  the  membrane  presents  deep  depres- 
sions ;  the  inclosed  body  of  the  Podophrya  acquires  on  its  surface  a  sharply- 
defined  smooth  membrane,  whilst  the  contents  of  the  body  become  somewhat 
opaque,  enclosing  a  round  clear  space.  The  Podophrya-ajst  thus  formed  is 
supported  by  a  peduncle,  which  is  widened  at  the  base.     In  many  instances 


254  GENERAL  HISTORY  OF  THE  INFUSORIA. 

in  which  the  membrane  was  not  plicated,  but  loosely  enclosed  the  Podophrya 
like  a  sac,  I  noticed  that  the  peduncle  of  the  cyst  was  continued  uninterrupt- 
edly into  the  membrane,  of  which  consequently  it  must  be  regarded  as  a  pro- 
trusion, and  that  it  had  no  connexion  whatever  with  the  original  slender  pe- 
duncle of  the  Podophrya  itself.  In  fact,  I  noticed  cysts  in  which  this  original 
slender  peduncle  was  appended  to  the  saccular  envelope.  I  am  unable,  there- 
fore, to  adopt  Stein's  view  that  the  Podophryce  are  enclosed  in  a  membrane, 
of  which  the  slender  peduncle  is  simply  a  tubular  protrusion.  This  is  true 
only  with  respect  to  the  short  peduncle  of  the  encysted  Podopliryce. 

"  What  afterwards  becomes  of  the  cysts  I  have  been  unable,  in  spite  of  ob- 
servations continued  for  months,  to  determine." 

Multiplication  by  Spontaneous  Division  seems  now  to  be  sufficiently  de- 
monstrated. Ehrenberg  and  other  earlier  writers,  indeed,  mentioned  the 
occurrence  of  self-fission ;  but  their  accounts  were  too  uncertain  and  inde- 
finite, and  strong  doubts  prevailed  whether  they  had  actually  witnessed  that 
process,  or  the  act  of  conjugation,  to  be  presently  noticed.  Mr.  Brightwell 
appears  {Fauna  Infusoria  of  Norfolk)  to  have  confounded  the  two  processes  ; 
for  he  says — "  They  multiply  by  division,  so  that  two  and  sometimes  three 
individuals  are  seen  adhering  together  by  theii'  outer  edge — the  middle  one, 
the  parent,  being  the  largest," — an  explanation  inconsistent  with  the  process 
of  fission  as  generally  understood.  Claparede  states  distinctly  that  he  has 
seen  the  act  of  fission ;  "Weston  describes  it  in  Actinoplirys,  and  Cienkowsky 
in  Podophrya.  "  With  regard  to  the  reproduction  of  Actinophrys  Sol/'  writes 
Mr.  Watson  (op.  cit.  p.  119),  "  I  can  positively  affirm  that  self-division  is 
one  mode ;  for  I  may  say  I  have  witnessed  it  a  hundred  times  and  shown  it 
to  others ....  First  was  noticed  a  deep  depression  above  and  below,  not  far 
from  the  centre  of  the  body  ;  this,  as  it  increased,  threw  the  tentacles  across 
each  other,  in  a  manner  similar  to  that  described  by  Kolliker,  when  in  the 
act  of  inclosing  an  object  of  prey.  This  crossing,  however,  in  the  act  of  self- 
division  would  appear  to  be  only  the  necessaiy  consequence  of  the  depressions 
alluded  to,  and  the  position  into  which  the  outer  membrane  (in  which  the 
tentacles  are  inserted)  is  drawn.  As  division  proceeded  (XXIII.  31),  the 
two  animalcules  steadily,  but  rather  quickly,  increased  the  distance  between 
them,  until  the  connecting  medium  was  apparently  a  long  membranous  neck, 
which,  to  my  unpractised  eye,  appeared  composed  first  of  four,  then  of  three, 
then  two  irregular  lines  of  cells  (possessing  no  nuclei),  which  ultimately  di- 
minished into  a  single  cord  composed  of  three  simple  cells  elongated  like  the 
links  of  a  chain,  this  becoming  gradually  more  attenuated,  imtil  the  exact 
moment  of  its  division  could  not  be  seen.  All  this  latter  portion  of  the  pro- 
cess was  rather  rapidly  performed, — that  is,  from  the  first  formation  of  the  rows 
of  cells  to  the  time  of  what  I  supposed  to  be  the  final  separation,  occupied 
only  about  a  quarter  of  an  hour ....  During  the  whole  of  the  process,  the  valve 
(^.  e.  the  expanding  and  contracting  superficial  vacuole)  of  each  segment,  situ- 
ated at  nearly  opposite  extremes,  was  in  constant  action,  and  each  creatui-e 
Avas  busily  employed  seizing  its  food."  On  following  one  segment  after  its 
separation,  "  a  floating  faint  line,  the  broken  thread  "  (of  connexion),  extended 
from  it;  and  two  of  the  cells,  formerly  contained  within  this  bond,  were  attached 
to  its  side,  but  were  in  a  few  minutes  drawn  into  the  body  of  the  Actinophrys, 
which  there  assumed  a  perfectly  normal  character.  In  Podophrya  the  process 
of  fission  is  similar  (XXIII.  34) ;  at  first  an  annular  constriction  displays  it- 
self, and  so  rapidly  deepens,  that  in  an  about  half- an -hour  complete  trans- 
verse fission  is  effected.  The  history  of  the  segments  is  thus  portrayed  by 
Cienkowsky  (ojd.  cit.  p.  98),  about  ten  minutes  after  the  commencement  of  the 
act  of  division: — "The  upper  segment  had  assumed  an  elongated  form,  was  more 


OF  THE  PROTOZOA. ACTINOPIIRYmA.  255 

cylindiical,  a  little  indented  in  the  middle,  and  I'oimded  at  each  end ;  and  at 
the  extremities,  slight  oscillations  to  the  right  and  left  could  be  perceived.  A 
transverse,  and  frequently  curved,  nucleus  was  visible  in  the  fluid  contents  ; 
and  a  lateral  contractile  space  could  be  clearly  distinguished  in  the  upper 
parts.  The  vibrations  increased  in  frequency  and  force  until  the  segment 
became  whoUy  detached  and  escaped.  During  the  process  of  division  both 
segments  were  furnished  with  tentacles ;  but  when  the  oscillations  of  the 
cylindrical  portion  commenced,  very  fine  and  short  cilia  might  be  seen,  though 
with  difficulty,  vibrating  on  the  free  end, — the  tentacles  at  the  same  time  being 
retracted,  and  remaining  visible  only  on  the  posterior  segment.  I  now  followed 
uninterruptedly  the  movements  of  the  liberated  segments.  They  moved  for  the 
most  part  in  curved  Hues,  in  the  course  of  which  the  motile  segment  appeared 
to  seek  the  illuminated  side  of  the  drop  of  water.  Cilia  could  not  be  perceived 
over  the  whole  sm-face.  The  contractile  space  during  the  movements  was  al- 
ways in  front.  The  motions  were  rapid,  but  still  such  as  to  allow  of  their  being 
followed  with  a  magnifying  power  of  370  diam.  After  waiting  patiently  for 
twenty  minutes,  I  saw  the  motion  cease ;  and  at  the  same  time  short  tentacles 
made  their  appearance,  which  were  protruded  more  and  more  ;  and  in  a  few 
minutes  afterwards  the  segment  regained  the  spherical  form :  thus,  after 
moving  about  freely  for  a  time,  it  was  again  transformed  into  a  Todoplirya. 

"  This  process  of  division  was  witnessed  by  other  observers.  It  takes  place 
more  especially  when  sufficient  nutriment  is  supplied  by  numerous  Stylony- 
cMce  to  the  PodopTiryce.  The  Podoi^hrya  does  not  always  divide  into  two 
equal  halves ;  the  segments  are  more  frequently  unequal.  After  repeated 
division,  the  specimens  always  become  more  transparent."  This  temporary 
production  of  vibratile  cilia  from  the  surface  of  one  of  the  Actinopliryina,  in 
connexion  with  the  process  of  fission,  is  a  phenomenon  so  opposed  to  received 
notions,  that  it  will  necessarily  be  admitted  with  great  reserve  until  confirmed 
by  repeated  observation. 

The  process  of  Gemmation  is  recorded  by  Lachmann  to  occur  in  Dendrosoma 
radians,  a  being  of  which  we  know  too  httle  to  pronounce  with  certainty  if  it 
be  one  of  the  Actinophryina  or  of  the  Acinetina.  He  says  (op.  cit.  p.  231) — 
"  In  Dendrosoma  radians,  Ehr.,  a  branch  of  the  nucleus  grows  mto  the  bud 
whilst  it  still  remains  united  to  the  parent  animal." 

Reproduction  by  Embryos  or  Germs  has  been  presumed  by  several  autho- 
rities. Stein,  in  pursuing  the  history  of  the  organisms  he  identified  with 
ActinopJirys  Sol  and  PodopTirya  fixa,  satisfied  himself  of  the  successive 
development  in  their  interior  of  a  ciliated  germ,  which  he  compared  to  the 
gemma  of  a  Vorticella,  into  which,  indeed,  he  supposed  it  subsequently  to 
ftdly  unfold  itself  (XXIII.  2,  4,  5).  However,  as  before  noted,  Cienkowsky 
rejects  the  beings  observed  by  Stein  from  Actinophryina,  and  treats  them 
as  Acinetina ;  yet  he,  at  the  same  time,  confirms  the  production  of  ciHated 
motile  embryos  within  Acineta,  but  declares  them  reconverted  into  similar 
Podophryce  to  those  that  give  birth  to  them.  Apart  from  the  researches  of 
Stein,  which  have  invoked  so  much  attention  to  the  development  of  Protozoa 
generally,  and  particularly  to  that  of  Actinophryina  and  Acinetina,  the  idea 
that  the  members  of  the  former  family  probably  reproduce  themselves  by 
germs  has  been  suggested  by  the  occurrence  of  very  minute  individuals, 
either  alone  or  in  clusters.  Thus  KoUiker  remarks  (op.  cit.  p.  34)  that  the 
smallest  individuals  of  Actinophrys  Sol  measured  only  0-01"'  to  0-02'",  and 
presented  very  inconspicuous  and  few  granules,  and  that  the  granular  and 
vesicular  corpuscles  within  the  nuclear  portion  of  the  body  may  be  germs 
just  beginning  to  be  evolved.  Mr.  Weston  is  also  led  to  believe  in  the 
internal  generation  of  minute  germs ;  but  the  obseiTation  he  records,  as 


256  GENERAL  HISTORY  OF  THE  INFUSORIA. 

possibly  an  instance  of  such  a  process,  entirely  fails,  in  om^  opinion,  to  sus- 
tain the  supposition.  The  occurrence  alluded  to  was  that  of  a  thin,  pellicular, 
irregularly-shaped  sac — sometimes  of  two  or  three  such, — which  elevated  itself 
above  the  surface  of  the  ActinojDlirys,  and  presently  burst,  emitting  some 
fluid  and  fine  granular  matter,  and  then  contracted.  "  Does  this  emitted 
fluid,"  he  asks,  "  contain  the  germ  of  future  generations?"  We  think  not ; 
for,  to  our  mind,  the  phenomenon  mtnessed  was  nothing  more  than  the 
bursting  of  superficial  vacuola,  j^robably  acting  as  excrementory  media ;  and 
if  this  view  be  not  correct,  Mr.  Weston's  is  improbable,  inasmuch  as  such  a 
discharge  of  germs  from  superficial  sacs  is  without  parallel  in  the  history  of 
Protozoa. 

Conjugation. — The  remarkable  act  of  conjugation,  also  known  as  Zygosis, 
has  attracted  very  much  attention  in  the  class  of  animalcules  under  consi- 
deration, among  which  it  is  of  very  frequent  occurrence.  Much  discussion 
has  taken  place  concerning  the  purpose  of  this  process.  Most  of  its  early 
observers  considered  it  a  reproductive  act,  a  sort  of  copulation  between  two 
individuals ;  but  the  tendency  of  opinion  at  the  present  day  is  to  deny  it  this 
natui^e,  and  to  treat  it  as  little  more  than  an  accidental  phenomenon,  without 
apparent  object  or  aim.  Nevertheless  its  occurrence  is  so  fi-equent,  and  the 
process  of  so  complete  a  character,  that  it  is  hard  to  believe  it  to  be  in  vain 
and  to  no  purpose  in  the  economy  of  the  Actitiojpliryina.  A  difi'erence  of 
opinion  likewise  prevails  as  to  the  nature  of  the  process,  one  set  of  authors 
maintaining  that  there  is  an  actual  fusion  and  intermingling  of  substance 
between  the  conjugating  animals,  whilst  another  party  asserts  that  there  is 
no  fusion,  but  merely  a  temporary  adhesion  or  accretion  between  their  bodies. 
The  determination  of  this  question  is  very  necessary  before  we  can  speculate 
fairly  respecting  the  pui'pose  of  the  act.  Kolliker,  who  was  among  the  first 
to  carefully  explore  this  phenomenon,  described  it  as  a  process  of  complete 
fusion,  and  surmised  it  to  be  of  a  reproductive  character.  Stein  speaks  at 
one  place  of  conjugation  {op.  cit.  p.  148)  in  Act'moplirys  and  Fodophrya  as 
consisting  in  a  fusion  (  Verschmehung)  of  the  animalcule.  At  another  (p.  160) 
he  describes  it  as  an  organic  union  of  two  or  more  individuals  into  a  group, 
involving  no  fusion  of  their  contents,  but  only  a  cohesion  by  their  suii'aces ; 
and  goes  on  to  say  (p.  161)  that  the  coming  together  of  two  Actinoplirides  is 
due  to  external  forces,  and  that  the  first  thing  observed  is  an  entangHng 
together  of  their  tentacles,  which  act  precisely  in  the  same  manner  as  when 
a  foreign  body  is  seized  upon,  and  by  their  contraction  bring  the  bodies  into 
apposition.  At  the  same  time  they  fuse  together  and  form  a  sort  of  commis- 
sure, which  is  sometimes  areolated,  owing  to  interruptions  to  its  continuity 
by  the  incomplete  confluence  of  the  tentacles.  In  the  case  of  Act.  oculata, 
several — as  many  as  seven — individuals  were  seen  by  Stein  connected  toge- 
ther, in  a  line,  by  this  intermediate  commissural  matter,  which  he  calls  a 
common  mantle, — but  all  of  them  preserving  their  individuality,  just  as  in  the 
instance  of  other  species.  This  mode  of  connexion,  by  means  of  an  interposed 
matter  derived  fi'om  the  tentacula  of  the  conjoined  siu-faces,  explains  what  Stein 
means  by  conjugation  being  a  fasion  of  the  animalcules  concerned — not  a 
fusion  or  commingling  of  their  substance  in  general,  as  some  have  thought  it. 
Cohn,  in  his  account  of  the  conjugation  of  Actinoplwys  {Zeitschr.  Band  iii. 
p.  QQ),  noticed  the  connecting  band  or  commissure  to  sometimes  contain, 
besides  granules,  particles  of  food,  and  vacuola,  a  vesicular  body  which  he 
presumed  to  be  nuclear,  or  a  germ,  developed  as  a  consequence  of  the  zygosis 
in  operation.  Stein  encountered  once  or  oftener  a  similar  body,  but  concluded 
that  it  was  accidental,  probably  of  vegetable  origin,  and  not  in  any  degree 
embryonic;  and  (p.  164)  he  expresses  himself  satisfied  that  this  act  of  con- 


OF  THE  PROTOZOA. —  ACTINOPHRYIIfA.  257 

jugation  is  not  associated  with  the  reproductive  faculty.  In  fact,  he  has 
never  met  with  the  development  of  an  embrj'o  in  conjugated  individuals  of 
his  (Acinetiform)  Actinophrys  and  Podophrya.  Claparede  questions  {op. 
cit.  p.  286)  whether  the  compound  forms  noted  by  Stein  and  Perty  were,  as 
they  supposed,  all  derived  from  conjugation ;  and  he  proceeds  to  say  that,  if 
it  be  proved  that  more  than  two  individuals  may  thus  be  fused  together,  the 
connexion  of  conjugation  with  reproduction  will  become  exceedingly  doubtful, 
and  that  the  term  had  better  be  di'opped,  and  either  Stein's  phrase  "  process 
of  fusion,"  or  Ehrenberg's  word  "  zygosis,"  adopted  in  its  room.  Whatever 
value  attaches  to  Claparede's  deduction  from  the  circumstance  of  more  than 
two  being  fused  together,  there  can  be  no  doubt  that  this  may,  and  indeed  does 
frequently,  happen.  Lieberkiihn,  one  of  the  most  recent  investigators  of  this 
group  of  beings  (Zeitschr.  1856,  308),  recognizes  the  occurrence,  and  observes 
that  the  number  united  may  be  estimated  by  that  of  the  contractile  vesicles. 
The  process,  he  further  asserts,  is  not  one  of  genuine  conjugation,  but  merely 
a  temporaiy  cohesion  ;  for,  after  watching  a  group  for  six  hours,  he  saw  the 
separation  of  the  several  component  individuals,  preceded  by  a  narrowing  of 
the  connecting  bands  or  commissures.  Such  is  an  outline  of  the  opinions  and 
statements  of  some  leading  naturalists  respecting  the  nature  and  design  of 
this  so-called  act  of  conjugation.  The  balance  of  authority  and  evidence  is 
against  the  supposition  of  its  reproductive  purpose ;  but  when  this  view  is 
rejected,  we  have  no  other  to  replace  it,  and  are  sensible  of  the  want  of 
sufficient  data  from  dii'ect  observation  before  a  hopeful  attempt  can  be  made. 
Ehrenberg,  it  should  not  be  omitted  to  state  {Monatsb.  Berl.  Akad.  April 
1854),  started  the  notion  that  conjugation  is  intended  as  a  means  of  invigo- 
rating the  species :  "  a  curious  idea,"  says  Claparede  {op.  cit.  p.  286),  "  and 
not  Y&vy  reconcileable  with  the  ordinary  laws  of  nature." 

Kolliier  {op.  cit.  p.  100)  canvassed  the  question,  if  Actinophrjdna,  along 
with  Rhizopoda,  are  to  be  considered  cells,  and,  after  an  elaborate  examina- 
tion of  the  point,  concluded  that  they  must  be  regarded  as  peculiarly  modified 
simple  cells.  Claparede,  after  weighing  Kolliker's  arguments  and  reviewing 
the  stnictiu'al  peculiarities  of  these  animalcules,  comes  to  the  opposite  conclu- 
sion, viz.  that,  ''  as  regards  ActinopTirys  Sol  in  particular,  we  must  either 
drop  the  class  of  unicellular  animals  altogether,  or  refer  this  animal  to  some 
other  place."  We  do  not  deem  it  at  all  necessary  here  to  enter  upon  this  con- 
troversy ;  it  has  already  engaged  our  attention  in  other  places,  and  has  of  late 
lost  much  of  its  interest  by  the  extended  modifications  introduced  latterly  in 
that  particular  hypothesis  of  ceU-natui^e,  which,  at  the  date  of  Kolliker's 
paper  in  1849,  exerted  so  powerful  an  influence  over  the  histological  specu- 
lations of  all  the  writers  of  that  period. 

Localities. — Actinophryina  are  inhabitants  both  of  fresh  and  salt  water. 
They  occur  often  as  parasites  upon  the  larger  Protozoa,  such  as  Stylonychia, 
and  on  various  small  animals  of  other  classes,  and  seem  to  draw  nourishment 
from  them.  They  are  also  common  among  the  filaments  of  Conferva  and  the 
stalks  of  Lemna,  where  other  animalcules  congregate.  Another  locality  is 
amid  the  vegetable  debris  and  minute  animals  which  often  float  together,  as 
a  dust-like  film,  on  the  surface  of  ponds. 

Affinities  of  Actinopheyina. — All  recent  writers  refer  this  group  of  beings 
to  the  Ehizopoda,  except  Siebold,  who  curiously  enough  retains  Actinophrys 
in  the  family  Enchelia,  along  with  Leucophrys  and  Prorodon,  two  genera  of 
Cihata  of  quite  a  difi'erent  type  of  organization.  Although  the  preceding 
sketch  of  the  history  of  Actinophryitui  will  afford  ample  evidence  of  many 
homologies  with  the  Rhizopoda,  yet  it  will  equally  display  not  a  few  differ- 
ential characters,  sufficient,  we  believe,  to  separate  them  at  least  as  a  subclass. 


258  GENERAL  HISTOEY  OF  THE  INFUSORIA. 

The  most  striking  points  of  divergence  are  the  more  definite  and  constant 
figure  of  Act'inopliryina,  their  peculiarly  formed  tentacula  in  lieu  of  ordinary- 
variable  processes,  and,  of  minor  moment,  their  greater  immobility,  and  the 
operation  of  the  tentacles  in  the  introduction  of  food.  Acineta  was  placed  by 
Ehrenberg  with  Actinophrys  in  a  family  or  order  Acinetina  ;  and  most  writers 
treat  them  as  if  the  relation  between  these  two  families  were  actually  so  near. 
A  closer  attention  will,  however,  prove  that  something  more  than  a  generic 
diiference  subsists,  and  that  Acineta  had  better  stand  as  the  representative  of 
another  group,  well  named  Acinetina,  although  more  limited  in  its  significa- 
tion than  that  so  termed  by  Ehrenberg.  The  most  tangible  diff'erences 
between  Actinophryina  and  Acinetina  are,  that  no  food  enters  the  substance 
of  the  body  in  the  latter  group,  and  that  the  body  is  covered  with  an  integu- 
ment. The  history  of  this  division,  as  far  as  at  present  known,  reveals  yet 
other  distinctions  ;  for  self- division  has  never  been  observed,  whilst  the  pro- 
duction of  motile  ciliated  embryos  from  the  interior  has  been  seen  over  and 
over  again,  without,  as  far  as  is  known,  an  antecedent  act  of  conjugation.  It 
must  likewise  not  be  forgotten,  that  it  is  the  Acinetina  which,  according  to 
Stein's  hypothesis,  constitute  an  intermediate  phase  of  existence  in  the  de- 
velopment of  many  Vorticellina.  Indeed,  could  this  naturahst's  supposition 
be  proved,  the  existence  of  Acinetina  as  a  class  of  independent  beings  would 
at  once  be  sacrificed.  Another  afiinity  is  discoverable  with  the  Polycystina, 
both  in  the  natiu-e  of  the  soft,  muco- gelatinous  mass,  in  the  long,  tentacular 
filaments,  and  in  the  ciuTcnts  of  granules  detected  in  the  processes.  This 
relation  is  best  seen  with  some  Acanthometra  {vide  Midler's  paper,  Monats- 
hericlit,  Berlin,  April  1855).  The  Actinophryina  are  related  to  the  Ciliata  also 
by  their  sarcode,  by  the  structiu'e  and  action  of  the  contractile  vesicle,  b}"  the 
formation  of  alimentaiy  vacuoles,  and  by  the  nature  and  composition  of  their 
granules.  But,  over  and  above  these  general  resemblances,  a  more  special 
afiinity  is  manifested  if  Cienkowsky's  statement,  that  the  fission  produced  is 
clothed  with  vibratile  cilia,  be  correct.  This  degree  of  affinity  must  be  ad- 
mitted in  the  case  of  the  Acinetina  which  appear,  as  a  rule,  to  generate 
cihated  embryos. 

Since  the  above  history  was  written.  Dr.  StrethiU  Wright,  of  Edinburgh, 
has  most  kindly  furnished  us  with  notes  on  several  Infusoria,  among  others 
of  two  new  forms  of  Actinophryina,  presenting  great  peculiarities  in  struc- 
tui^e.  The  accoimt  of  these  novel  genera  wiU  be  found  in  the  second  part  of 
this  work,  in  the  Systematic  History  of  the  ActinopJiryina. 

SUBFAMILY  ACINETINA. 
(Plates  XXIII.  1-23;  XXYI.  3,  4;  XXX.  3,  4,  7,  8,  21-26.) 

The  reasons  for  separating  Acinetina  from  Actinophryina,  with  which  they 
have  generally  been  united,  have  been  stated  in  the  last  chapter,  where 
likewise  the  difierential  characters  of  the  two  groups,  and  the  supposed  part 
they  play  in  the  cycle  of  development  of  Vorticellina,  have  been  examined. 
There  remains  therefore,  to  fill  up  the  history  of  the  Acinetina,  nothing  more 
than  some  further  remarks  on  the  various  forms  they  assume,  and  on  certain 
peculiarities  in  their  structiu-e. 

The  form  of  Acinetoi  is  subject  to  great  variety.  Ppiform  and  ovoid  shapes 
are  the  most  prevalent ;  but  some  are  almost  spherical,  and  others,  again, 
nearly  triangular  (XXIII.  6,  7,  8, 15,  17,  22,  23).  A  lobulated  anterior  end 
is  common  ;  and  then  the  tentacles  are  usually  restricted  to  the  lobules  (6, 17, 
18).     These  lobed  forms  have  no  such  firm  integument  or  capsule  at  aU  as 


OF  THE  PEOTOZOA. ACINETINA.  259 

that  seen  in  others ;  or  the  anterior  lobed  part  is  undefended  by  such  a  cover- 
ing, except  of  a  very  delicate  and  yielding  structure.  Cienkowsky  speaks  of 
the  Acineta  he  examined  as  naked  without  limitary  membrane  (XXIII.  40). 
Very  frequently,  on  the  other  hand,  the  Acineta  is  entii^ely  enclosed  within 
a  stout  capsule.  This  capsule  is  readily  discerned  when,  as  frequently 
happens,  the  internal  animal  mass  of  the  Acineta  does  not  fill  it ;  or  it  may  be 
brought  into  view  by  the  application  of  diluted  acetic  acid  or  alcohol,  either 
of  which  causes  the  shrinking  of  the  contained  body.  In  general  the  capsule 
appears  to  be  a  very  thin,  coloiuiess,  hyaline  membrane ;  but  after  the  action 
of  acetic  acid.  Stein  represents  it  to  be,  in  the  supposed  Acineta  of  Ojyercularia 
Lichtensteinii,  of  considerable  thickness  (XXIII.  22,  23).  This  thickening 
is  doubtless  due  to  the  action  of  the  acid  in  causing  the  membrane  to  swell 
out.  With  the  exception  of  the  so-called  Actinojplirys  Sol  of  Stein,  and  the 
Dendrocometes,  the  Acinetina  are  attached  by  a  stalk  of  varying  length, 
more  commonly  very  short,  to  the  body  on  which  they  live  (XXIII.  17,  18, 
22 ;  XXYI.  3,  4).  This  stalk  or  pedicle  is  a  tubular  prolongation  backwards 
of  the  capsule  itself,  like  which,  it  is  hyaline  and  transparent. 

It  is  not  articulated  with  the  body  of  the  Acineta,  but  expands  more  or 
less  abruptly  into  the  capsule,  and  has  a  proportionately  greater  or  less 
infimdibuliform  figure.  Occasionally  the  stem  at  the  upper  part  has  trans- 
verse rugae,  and  in  a  few  instances  exhibits  a  sort  of  longitudinal  striae,  par- 
ticularly near  its  junction  with  the  body  (XXIII.  3,  4).  Stein  describes  the 
stem  of  the  supposed  Acineta  of  Ejnstylis,  to  be  solid  like  that  of  an  Ejpistylis 
itself.  Frequently  the  capsule  is  thrown  into  transverse  folds,  at  times,  of 
considerable  depth.  There  is  no  aperture  in  it ;  but  it  is  penetrated  by  the 
tentacles  which  rise  from  the  contained  organic  being.  The  capsule,  if  in 
some  specimens  of  considerable  firmness,  would  seem  to  be  in  others,  even 
when  thick,  very  yielding, — so  much  so  as  to  allow  great  variety  in  figure  by 
the  contractions  of  the  contained  body,  as  instanced  by  Stein  in  the  Acineta 
attributed  to  Opercidaria  Lichtensteinii.  The  tentacles  of  Acinetina  have  not 
the  imiformity  of  stnicture  seen  in  those  of  Actinoi^liryina.  In  some  Acinetce 
they  closely  resemble  those  of  ActinopJirys,  are  long,  gently  tapering,  and 
capitate ;  in  others  they  form  parallel  tubular  processes,  dilated  a  Httle,  or 
not  at  all,  at  the  extremity,  and  either  straight  or  slightly  curved  or  undu- 
lated ;  in  others,  again,  they  rather  resemble  bristles,  appear  stiff,  and  taper 
to  a  sharp  point.  In  the  remarkable  Acineta  called  Dendrocometes,  the 
tentacular  character  is  entii^ely  lost,  and  a  few  most  bizarre  branched  tubular 
processes  spring  from  one  to  six  points  of  the  surface  (XXX.  22,  23).  Per- 
haps these  processes  are  homologous  Avith  tentacles ;  yet,  imlike  them,  they 
seem  to  be  formed  from  the  capsule  of  the  animal,  into  which  the  granular 
contents  of  the  interior  penetrate,  as  into  hollow  tubules  prolonged  from  the 
surface  of  the  organism. 

In  certain  Acinetina  that  approach  Actinophrys  in  external  characters,  the 
tentacles  are  equally  difiused  over  the  body.  In  the  large  ppifonn  Acineta, 
assigned  by  Steia  to  Opercularia  articulata,  the  short  slender  tubular  pro- 
cesses appear  chiefly  marginal  (XXX.  3,  4).  The  digitate  Acineta  is  covered 
by  long  tapering  and  thick  processes  on  its  dorsal  convex  suiface  (XXIII. 
21) ;  and  the  Diademiform  Acineta  has  its  long  setiform  tentacles  in  twos 
and  threes  at  considerable  inteiwals,  chiefly  on  the  margin  (XXIII.  15,  16). 
The  Actinophryean  Acineta  of  Epistylis  plicatilis  bears  a  bundle  of  long 
finely  capitate  tentacula  on  each  of  its  four  lobes  (XYIII.  2) ;  that  of 
Vorticella  nehulifera  has  two  such  bundles, — whilst  the  triangular  Acineta, 
with  its  tongue-Hke  process  (XXIII.  17,  18,  19),  carries  a  large  expanding 
pencil  of  shorter  obtuse  tentacles  upon  each  angle  at  its  base. 

s2 


260  GENERAL  HISTOEY  OF  THE  INFUSORIA. 

The  tentacula  are  moveable  and  retractile,  the  divergent  bundles  may  be 
collected  into  parallel  groups,  and  di-awn  inwards,  with  the  protruding  sup- 
porting lobes,  to  a  greater  or  less  extent.  Stein  aifirms  that,  in  the  first  stage 
of  development,  Acinetce  have  no  tentacula. 

The  body  of  an  Acineta,  within  the  capsule  or  external  integument,  con- 
sists of  soft  colourless  sarcode,  rich  in  granules,  fat- corpuscles,  and  minute 
globules.  It  is  enveloped  by  an  elastic  yielding  membrane,  which  becomes 
most  distinct  when  the  body  shrivels  mthin  the  capacious  cavity  of  the 
capsule  (XXIII.  3,  6,  8).  The  body  appears  in  some  Acinetce  capable  of 
extending  itself  above  the  capsule,  which  must  therefore  be  fissured  in  front, 
in  the  form  of  a  tongue-hke  process  (XXIII.  17,  18,  19).  A  finely  granular 
and  opaque  nucleus  is  always  distinguishable  in  the  interior,  usually  near  the 
centre.  Its  shape  is  very  varied,  and  may  be  oval,  ovoid,  clavate,  reniform, 
band-like,  vermiform,  or  horse-shoe  shaped  (XXIII.  1,  6,  17,  22).  In  a 
few  examples,  e.  g.  of  the  supposed  Acineta  of  Opercularia,  it  is  much  and 
irregularly  branched  (XXX.  3,  4).  The  addition  of  dilute  acetic  acid  is  a 
ready  and  efifectual  means  of  bringing  the  nucleus  to  hght,  and  of  demon- 
strating its  enclosing  sac ;  and  as  it  is  more  solid  and  compact  than  the 
contents  around  it,  it  may  now  and  then  be  separated  by  crusliing  the  Acineta. 
The  nucleus  is  enveloped  by  its  peculiar  membrane ;  a  fact  which  becomes 
e\'ident  in  sevei^al  cases  by  the  apparent  double  line  surrounding  its  gra- 
nular mass  (XXIII.  6-22).  In  a  few  instances,  moreover.  Stein  has  de- 
scribed a  contractile  space  witliin  the  nucleus,  e.  g.  in  that  of  Opeixularia 
berberina. 

Xot  unfrequently  the  nucleus  looks  as  if  double,  or  as  sending  ofi*  a  process 
from  itself;  a  critical  examination  of  such  specimens  has  convinced  Stein  that 
the  ofi'shoot  is  the  commencing  development  of  the  germ  or  embiyo  of  the 
Acineta  (XXIII.  7,  8,  19).  This  he  has  proved  by  watching  the  nucleus 
through  all  its  intermediate  stages,  from  a  simple  ovoid  or  elongated  figure 
until  the  embiyo  has  gro^Ti  and  separated  itself  from  it  prior  to  its  escape 
from  the  Acineta.  The  nuclear  appendix,  when  separated,  is  found  to  have 
an  enclosing  membrane,  which  ultimately  surrounds  the  embiyo  like  a  sac, 
and  admits  of  a  certain  degree  of  movement  within  it  (XXIII.  4,  5). 

Another  distinct  organ  of  Acinetina  is  the  contractile  vesicle.  Usually  one 
only  is  present ;  but  in  some  instances  two,  and  more  rarely  three  or  more, 
make  their  appearance  (XXIII.  1,  5, 21).  Xear  the  external  margin  a  series 
of  clear  vesicular  or  vacuolar  spaces  presents  itself,  as  in  the  Diademiform 
Acineta  (XXIII.  15, 16)  ;  such,  however,  present  no  rhythmical  contractions, 
and  cannot  be  regarded  as  true  contractile  sacs.  The  embryos  developed 
from  Acinetw  are  likewise  furnished  with  one,  and  occasionally  mth  two,  of 
those  organs  (XXIII.  2,  4,  5,  15,  27).  Excepting  the  embryos  or  germs,  no 
other  special  structures  are  seen  amid  the  granular  contents  of  Acinetina. 
Alimentary  vacuoles  and  particles  of  food  or  other  matters  derived  from  with- 
out never  make  their  appearance ;  for  the  body,  even  if  not  entii'ely  enclosed 
within  the  shut  sac  or  capsule,  is  covered  with  an  integument,  and  has  no 
sign  of  a  mouth  for  the  admission  of  food.  Yet  Acineta;  generally  have  the 
power  of  nourishing  themselves,  by  the  medium  of  their  tentacula,  which 
appear  to  act  as  suckers,  di'awing  in  by  endosmosis  the  nutrient  juices  from 
the  animalcules  which  get  entangled  by  them. 

If  Stein's  details  be  correct,  some  Acinetiform  beings  would  appear  to  have 
no  power  of  self-nutrition  ;  for  their  substance  is  described  as  gradually  used 
up  in  the  formation  of  germs,  and  this  decrease  to  be  followed  by  a  shrinking 
or  collapse  of  the  capsule,  but  at  a  comparatively  slower  rate.  Tliis  phe- 
nomenon  is   illustrated   by   Stein   in    the  Acineta    ascribed   to    Vaginicola 


OF  THE  PROTOZOA. ACINETINA.  261 

aystalUna,  and  in  the  so-called  Acimta  with  the  tongue-like  process 
(XXIII.  17,  20). 

If  this  account  be  admitted,  that  certain  Acinetce  display  no  power  of  self- 
nutrition,  and  seem  destined  only  to  subserve,  as  mere  media,  the  purposes  of 
reproduction,  an  independent  nature  could  scarcely  be  attributed  to  such 
beings,  and  their  history  would  be  entirely  comprehended  in  that  of  the 
beings  in  whose  cycle  of  development  they  might  enter  as  one  link.  Lach- 
mann  (A.  N.  H.  1857,  xix.  p.  222)  has  the  follomng  account  of  the  mode  in 
which  Acinetina  nourish  themselves : — "Each  ray"  (tentacle)  "is  a  sucking 
proboscis,  and  we  soon  see  that  a  cuiTent  of  chjTue-particles  runs  from  the 
alimentarj'  cavit}'  of  the  captured  Infusorium  into  the  body  of  the  Acinetaj 
through  the  axis  of  the  rays,  which,  after  seizing  the  prey,  have  become 
shortened  and  thickened.  In  the  body  of  the  Acineta  the  chyme-particles 
still  run  at  first  in  a  slender  row,  but  afterwards  they  coUect  in  a  di'op,  which 
although  drops  are  also  formed  in  the  chjTne  of  the  Acineta  by  other  suckers, 
soon  becomes  amalgamated  with  these.  AMien  a  considerable  quantity  of  the 
chyme  of  the  captured  animal  has  passed  over  into  the  body  of  the  Acineta^ 
a  remarkable  change  gradually  takes  place  in  its  appearance:  if  it  was  pre\dously 
pale,  nearly  transparent,  and  only  very  finely  granulated,  larger  dark  globules, 
resembKng  fat-di'ops,  now  make  their  appearance  here  and  there  ;  and  these 
soon  increase  so  that  the  body  (which  at  the  same  time,  of  coui^se,  increases 
in  thickness)  acquires  a  coarsely-granular  aspect,  and  becomes  opaque.  The 
globules  or  drops  which  make  their  appearance  can  only  be  formed  in  the 
body  of  the  Acineta,  as  they  are  far  larger  than  the  chyme-particles  which 
are  seen  flowing  through  the  sucker.  The  animal  whose  contents  are  thus 
sucked  out,  gradually  coUapses  and  dies  ;  many  become  liquefied  when  only 
a  little  of  the  chyme  is  extracted  from  them,  others  still  live  for  a  long  time ; 
in  large  animals,  such  as  Stylonychia  Mytilus,  Paramecium  Aurelia,  &c.,  the 
sucking  often  continues  for  several  hours." 

Origin'  and  Development  of  Ace^etina. — In  our  history  of  the  development 
of  Vorticellina,  Stein's  hypothesis  of  the  transformation  of  those  highly-de- 
veloped Ciliata  into  Acinetiform  beings  as  a  stage  of  existence  necessary  to 
their  development  by  embryos,  and  of  the  reconversion  of  the  embryos  into 
Ciliata  of  the  primitive  type,  is  sufficiently  enlarged  upon.  In  the  same 
chapter,  moreover,  Cienkowsky's  contradictory  statement  and  observation  are 
detailed,  viz.  that,  though  Acinetce  develope  ciliated  embiyos,  yet  these 
embryos  give  origin  to  beings  like  those  they  issue  from,  and  are  not  trans- 
formed into  Vorticellhia.  According  to  this  opinion,  the  Acinetina  take  a 
position  as  independent  beings  in  the  animal  series.  Stein  determined,  to 
his  own  satisfaction,  an  Acinetiform  phase  in  the  following  Vorticellina  and 
Ophrydina  : — 

Cothurnia  maritima.  SpirocJiona  gemmipara. 

Epistylis  branchiophila.  Vaginicola  crystallina. 

Opercularia  articulata.  VorticeUa  microstoma, 

Opercularia  berberina.  VorticeUa  nebulifera. 

Opercularia  Lichtensteinii .  ZootJiamnium  affine, 

Ophrydium  versatile.  CarcTiesium  pygmceum  ? 

The  description  of  the  Acinetiform  beings  assigned  to  the  species  enume- 
rated is  given  in  the  Systematic  History  of  the  Acinetina,  which  wiU  likewise 
afford  a  more  complete  idea  of  the  structure  and  forms  of  this  peculiar  class 
of  beings  than  the  above  general  history  itself. 


262  GENERAL  HISTORY  OF  THE  INFUSORIA. 

SUPPLEMEl^TARY  FAMILIES  OF  PROTOZOA. 

A. — Gregarinida.  Their  General  Characters,  Structure,  and  Affini- 
ties.— The  Gregar'inida  constitute  one  of  the  three  groups  into  which  several 
eminent  naturalists  subdivide  the  Protozoa  ;  they  therefore  claim  from  us  a 
brief  description. 

They  are  of  the  most  simple  structure ;  indeed,  some  writers  place  them 
below  the  Rhizopods  in  the  animal  series,  because,  unlike  these,  their  simple 
type  undergoes  no  further  elaboration  or  developmental  complication.  They 
are  parasites,  living  in  the  visceral  cavities  of  other  animals,  and  in  their 
simple  structure  are  comparable  to  a  cell,  or  to  the  o^iim  of  higher  animals. 
Thus  they  consist  of  a  homogeneous  albuminous -like  matter,  -with  numerous 
granules  of  coarser  and  finer  character  and  fat-like  globules,  enclosed  within 
a  membrane  of  more  or  less  perfect  structure,  which  in  all  essential  points 
I'epresents  a  cell-wall;  besides,  they  have  always  one  distinct  central  vesicular 
body  or  space  containing  one  or  more  granules,  and  evidently  of  the  nature 
of  a  nucleus.  Of  these  parts,  the  general  mass  may  be  taken  to  resemble  the 
yelk-matter,  and  the  nucleus  the  germinal  vesicle  of  an  ovum. 

The  enclosing  membrane  is  very  yielding,  and  admits  of  great  and  constantly 
fluctuating  alterations  of  figure  by  the  varying  contractions  and  extensions 
of  the  internal  contractile  mass  ;  but  there  is  no  such  thing  as  the  formation 
of  pseudopodes,  as  happens  among  Ehizopoda.  It  is  entire,  without  orifice 
either  in  the  shape  of  a  mouth  or  anus ;  consequently  no  foreign  particles  are 
ever  seen  in  the  interior.  Moreover,  the  Grer/arinida  contain  no  contractile 
vesicle,  and  have  never  been  found  to  undergo  either  fission  or  gemmation. 
Their  vital  endowments  are  so  shght,  that  their  animahty  is  at  fii'st  sight 
doubtful ;  but,  imlike  vegetable  organisms,  their  envelope  contains  no  cellulose. 

The  above  brief  account  comprehends  all  that  can  be  stated  generally  of  the 
organization  of  these  simple  creatures,  which,  if  above  the  Amoebcea  in  the 
possession  of  a  more  or  less  definite  membrane,  yet  sink  beneath  them  in  not 
possessing  a  contractile  vesicle. 

Notwithstanding  their  simplicity  of  structure,  they  yet  are  truly  animal 
organisms,  enjoying  an  independent  existence,  manifesting  the  phenomena  of 
motion,  growth,  nutrition,  and  reproduction,  in  the  last  of  which  they  exhibit 
a  peculiar  cycle  of  changes. 

Moreover,  there  are  various  notable  difierences  between  the  various  Grega- 
rinida  known,  with  respect  to  size,  figure,  to  the  activity  of  their  functions, 
and  to  some  minuter  points  of  structm^e.  Hence  theii-  division  into  genera 
and  species. 

In  size  they  vary  from  foiu'  or  five  lines  (as  in  the  genus  Didymojplirys)  to 
a  few  thousandths  of  an  inch.  Of  their  figure,  some  are  simply  rounded  or 
oval  sacs,  as  in  Monocystis ;  others  constricted  around  the  middle,  e.  g.  Grega- 
rinida.  Again,  the  majority  have  a  smooth,  naked  membrane,  whilst  others 
are  armed  with  a  ring  of  uncini  at  one  extremity,  like  many  Hehninthidce. 

When  two  nuclei  occur  in  a  single  animal,  it  probably  betokens  an  act  of 
reproduction.  The  encysting  process  is  exhibited  among  the  Gregarinida,  in 
connexion,  however,  onl}^  with  their  reproductive  processes,  and  has  this  pe- 
culiarity, that  it  does  not  occur  to  a  single  individual,  but  to  two  together, 
which  become  enclosed  within  the  common  cyst  or  capsule.  In  their  progress 
to  this  union  the  two  Gregarince  are  seen  first  to  approach,  and  then  by  mu- 
tual pressiu^e  to  flatten,  the  opposed  surfaces,  so  that  the  binate  being  acquires 
a  globular  form.  The  substance  to  form  the  cyst  is  in  the  meantime  thrown 
out,  of  a  soft  gelatinous  consistence,  but  gradually  becomes  condensed  and 
contracted  into  a  membranous -looking  capsule. 


OF  THE  PROTOZOA. GEEGAEINIDA. 

Stein  stated  that,  on  the  completion  of  the  act  of  apposition,  an  actual 
fusion  of  the  contents  of  the  two  animals  transpired,  the  opposed  walls  being 
previously  removed  by  absorption.  Other  observers  state,  however,  that  there 
is  no  such  removal  of  the  external  membranes,  and  that  the  reproductive 
processes  in  the  interior  of  each  being  proceed  without  any  real  commingling 
of  their  contents,  which  is  a  subsequent  and  probably  not  a  necessary 
event. 

This  act,  which,  fi'om  its  general  resemblance  to  the  zygosis  of  plants,  is 
spoken  of  as  one  of  conjugation,  appears  immediately  concerned  in  the  de- 
velopment of  a  multitude  of  germs  "svithin  each  Gregcunna,  by  the  general 
breaking  up  of  the  granular  contents.  Still,  if  Lieberkiihn's  account  be  ad- 
mitted, this  process  of  conjugation  is  not  a  necessary  prelude  to  the  develop- 
ment of  the  internal  germs ;  for,  according  to  it,  this  result  may  accrue  in 
individuals  which  have  never  conjugated. 

The  germs  assume  a  rod-  or  spindle-shaped  figure,  which,  from  its  re- 
semblance to  the  prevailing  form  of  the  Naviculce,  has  suggested  for  them  the 
name  of  "  J^avicellce  "  or  "  pseudo-Navicellce.^^  They  consist  of  an  external 
comparatively  firm  wall,  enclosing  a  finely-granular  gelatinous  substance. 

When  the  *'  Navicellce  "  are  sufficiently  matui^e,  the  cyst  of  the  Gregarince 
biu'sts  and  sets  them  at  large.  Their  future  history,  according  to  Lieberkiihn's 
researches,  is,  that  the  case  of  each  jpseiido-Navicella  ruptures  and  gives  exit 
to  the  soft  contained  matter,  which  at  fii'st  much  resembles  a  minute  Amoeba, 
but  gradually  assumes,  by  progressive  growth  and  the  formation  of  a  pellicle 
around  it,  the  characters  of  a  Gregarina. 

Between  this  mode  of  development  of  Gregarinida  and  that  of  the  Ciliated 
Protozoa,  Leuckart  draws  this  distinction,  that  in  the  former  it  consists  in 
the  production  of  granular  germs,  in  the  latter  of  living  embryos.  But  it  may 
be  questioned  whether  there  is  a  positive  difference  in  kind  between  these 
two  results  of  the  reproductive  process,  and  whether,  on  the  contrary,  the 
Navicellce  of  the  Gregarinida  may  not  be  considered  as  merely  encysted  em- 
bryos, homologous  with  those  of  Colpoda  Cucidliis  among  the  CiLiata. 

The  act  of  conjugation  in  the  Gregarinida  is  not  precisely  like  that  occui'- 
ring  among  the  lower  Algae,  the  leading  difference  being  that  in  the  former 
there  is  no  commixture  of  the  two  approximated  beings.  In  all  essentials, 
indeed,  conjugation  in  this  family  resembles  that  believed  to  happen  in  the 
Actinophryina. 

There  has  been  much  dispute  whether  the  Gregarinida  are  to  be  held  in- 
dependent animals,  or  merely  embryonic  phases  of  others ;  the  balance  of 
authority  is  in  favour  of  the  former  view.  Kolliker  and  Leydig  advocated 
the  opinion  that  they  are  metamorphic  stages  of  Anguillulce  or  Filarice,  or  a 
link  in  the  series  of  development  of  the  Helminthidce.  The  arguments  adduced 
by  Leydig  are  thus  briefly  stated  (J.  M.  S.  i.  p.  208,  and  Miiller's  Archiv, 
1851) : — "  In  the  intestine  of  a  large  species  of  TereheUa  he  was  enabled  to 
observe  the  most  distinct  transition  between  Filaria-like  Nematoid  wonns  and 
Gregarince.  The  forms  of  the  latter,  which  he  observed  not  once  only,  but 
many  times,  were — 1.  A  Gregarina  of  from  0-02'"  to  0'04'"  long,  which  had 
the  form  of  an  elongated  sac,  rounded  at  one  extremity,  and  sharp  at  the 
other.  The  contents  were  those  usual  in  the  Gregarince — a  consistent  fluid 
with  a  corpuscular  substance,  which  did  not  occupy  the  pointed  end,  and  im- 
bedded in  this  a  clear  vesicle  -^ith  a  nucleus.  2.  A  Gregaiiniform  creature, 
of  a  spindle-shaped  figure,  closely  resembling  Gregarina  Terehellce,  Kohh 
3.  A  Gregarina,  generally  resembling  the  preceding,  differing  only  in  two 
particulars :  the  internal  substance  is  arranged  in  longitudinal  streaks  ^ 
and  the  body,  instead  of  being  straight,  is  more  or  less  curved  at  each  end. 


264  GENEKAL  HISTORY  OF  THE  INFUSOEIA. 

4.  The  same  form,  but  with  the  body  more  elongated,  vermiform,  and  for  the 
first  time  exhibiting  motion.  5.  A  very  pretty  Nematoid  worm,  about  0*10'" 
long,  blunt  at  one  end,  sharp  at  the  other;  the  contents  in  longitudinal 
streaks,  as  in  the  two  preceding  forms,  but  with  the  spaces  between  them 
wider.     Its  motions  are  very  active." 

This  view  of  a  metamorphosis  being  admitted,  the  question  arises,  do  the 
Gregarince  become  changed  into  Filarice  ?  or  is  it  that  the  Filaria-like  worms 
are  transformed  into  Gregarince  ?  Although  at  first  inclined  to  consider  the 
former  as  the  true  state  of  the  case,  Leydig  is  now  disposed  to  follow  Heule 
and  Bruch,  and  adopt  the  latter  view ;  otherwise  it  would  seem  impossible 
to  account  for  the  formation  of  the  pseudo-Navicellce  and  "  Psorospermia  " 
within  the  "  Gregarince.^' 

KolHker  has  the  following  remarks  on  this  subject  (J.  M.  S.  i.  p.  212) : — 
"  Although  the  change  of  a  FUciria  into  a  Gregarina  is  not  an  impossible  cir- 
cumstance, before  we  admit  such  a  thing  it  is  first  necessary  to  inquire  whe- 
ther the  facts  stated  may  not  be  otherwise  explained.  It  is  by  no  means 
proved  that  the  Anguillula-^e  animal  noticed  by  Henle,  and  termed  by 
Bruch  Filaria,  is  really  a  Nematoid  worm."  Kolliker  is  more  inclined  to 
regard  it  as  an  Infusorium  allied  to  Oj^cdina,  Proteus,  &c.  If  this  be  the  case, 
there  is  nothing  extraordinary  in  its  transformation  into  a  Gregarina,  and 
finally  into  a  Navicella-rece^iOiQle. 

"  For  many  reasons,"  says  Stein  (Zeitschr.  iii.  1852),  "  the  endeavour  to 
show  the  Gregarince  to  be  larvae  of  higher  animals,  and  especially  to  connect 
them  with  encysted  Nematoid  worms,  appears  to  be  a  vain  attempt.  Thus,  I 
am  acquainted  with  Gregarince  of  such  peculiar  fonns  that  one  requires  a 
very  strong  imagination  to  deduce  them  from  Nematoiclea,  or  to  suppose  they 
can  pass  into  these.  The  encysted  Nematoiclea  are  always  found  in  the  cavity 
of  the  body  of  insects,  never  in  their  intestinal  canal,  where  alone  encysted 
Gregarince  are  to  be  found."  Again,  the  cysts  of  the  Nematoidea  of  insects 
are  made  up  of  nucleated  cells,  and  are  plainly  a  product  of  the  vital  activity  of 
the  insects,  not  the  exudation  of  the  enclosed  worm,  while  the  cysts  of  Gre- 
garince are  produced  as  an  amorphous  secretion  from  the  animals  themselves. 
*'  If,  therefore,  encysted  Nematoiclea  change  into  Gregarince,  or  vice  versa,  their 
cyst  must  undergo  a  metamorphosis  which,  perhaps,  no  one  will  assume,  and 
of  which  no  observer  has  seen  anything." 

Lieberkiihn's  observations  have  gone  far  in  shomng  that,  under  usual  con- 
ditions at  least,  the  Gregarinida  are  not  converted  into  Filarice  or  any  other 
form  of  Vermes,  but  that  their  germs,  after  a  short-lived  Amoebiform  period, 
not  amounting,  however,  to  a  true  metamorphic  stage,  assume  the  characters 
of  their  parent.  Thus  the  cycle  of  development  of  these  beings  appears  com- 
plete ;  the  saccular  animal  constructs,  by  a  process  of  segmentation  of  its  in- 
ternal substance,  a  host  of  germs,  which,  after  breaking  loose  from  their 
parent  and  involving  its  destruction,  emerge  from  their  cases  in  a  soft  Amoe- 
biform condition,  and  soon  acquire  the  matui'e  Gregariniform  condition.  The 
Gregarinida  exhibit  a  marked  affinity  with  other  Entozoa,  particularly  with 
the  Trematoda  and  Opcdincea  ;  and,  as  before  remarked,  they  are  allied  with 
the  Amcehcea  in  the  extreme  simplicity  of  their  stnicture.  By  the  possession 
of  a  limiting  membrane  (not  independent  or  separable,  indeed),  they  stand 
between  the  mucilaginous  fluctuating  Amoehcea  and  the  Ciliated  Protozoa. 
Unlike  the  Amoehcea,  they  do  not  receive  into  their  substance  solid  particles, 
— a  circumstance  explicable  by  their  being  covered  by  a  somewhat  resistant, 
hardened  lamina  or  tegument,  which  necessarily  impedes  that  peculiar  intus- 
susception of  solid  matters  witnessed  in  that  familj^ 

As  to  habitat,  the  Gregarinida  are  parasites  in  the  intestines  of  various  In- 


OF  THE  PROTOZOA. PSOROSPERMIA.  265 

vertebrate  animals — worms,  moUusks,  and  insects, — but  have  not  been  found 
in  Vertebrata. 

B. — PsoROSPERMiA  (Plate  XXII.  37-41). — This  is  a  small  group  of  para- 
sitic animals,  first  observed  by  John  Miiller  in  1841,  closely  related  to  the 
Gregarinida,  of  which,  indeed,  they  might  be  included  as  members.  Unlike 
the  Oregarince,  they  live  upon  vertebrate  animals,  viz.  upon  many  species  of 
fish,  about  their  skin,  giUs,  and  internal  organs,  several  together  enclosed 
within  sacs. 

Leydig  has  more  recently  applied  himself  to  the  study  of  these  minute 
parasites,  and  has  given  the  results  of  his  observations  in  Miiller's  Archiv  for 
1851,  of  which  an  abstract  appeared  in  the  Journ.  of  Mic.  Science,  i.  p.  206, 
which  we  shall  here  take  the  liberty  of  using,  as  sufficient  for  our  pui'- 
pose : — 

'^  The  Psorospermia  are  microscopical  corpuscles  of  a  peculiar  kind,  which 
may  be  generally  characterized,  in  the  full-gro^Ti  condition,  as  rounded 
organisms,  having  a  sharply- defined  outline,  with  or  without  a  tail-like  ap- 
pendage. They  are  flattened  and  lenticular  in  figure,  and  one  pole  is  usually 
acuminate ;  and  towards  this  pole  several  internal  vesicles  converge  in  a 
symmetrical  manner.  These  creatures  were  discovered  by  John  Miiller  in 
1841  (Miill.  Archiv,  1841,  p.  477).  He  found  in  a  j^oung  pike  minute  round 
cysts  in  the  cellular  tissue  of  the  muscles  of  the  eye,  in  the  substance  of  the 
sclerotica,  and  between  this  and  the  chloroid  coat.  The  contents  of  the  cysts 
was  a  whitish  substance,  which,  when  examined  microscopically,  Avas  found 
to  consist  of  peculiar  elements — the  '  Psorospermia.^  [A  detailed  notice  of 
these  observations  is  given  in  the  Microscop.  Journal,  vol.  ii.  p.  123,  and  in 
the  Brit,  and  Foreign  Med.  Rev.,  January,  1842.]  In  the  following  year  the 
same  observer  (Miiller's  Archiv,  1842,  p.  193)  discovered  parasitic  corpuscles 
in  the  swimming-bladder  of  a  Gadus  CaUarias,  which,  although  specifically 
distinct  from  the  Psorospermia,  approached  very  near  to  the  latter  in  their 
organization.  They  resembled  in  general  a  smooth  ventricose  Navicula,  and 
consisted  of  two  elongated  cases  apphed  to  each  other  at  the  cavity,  and  with 
an  elliptical  outline  and  convex  outer  surface.  They  were  in  part  free,  in 
part  enclosed  in  masses  within  a  tunic.  Similar  cysts,  containing  Psorosper- 
mia, have  been  found  by  Leydig  in  several  species  of  fish,  and  in  aU  parts 
nearly  of  their  bodies,  and  even  in  the  blood  contained  in  the  heart  and  in 
the  peritoneal  cavity. 

"  Some  facts,  however,  observed  by  him,  connected  with  this  subject,  which 
came  under  his  notice  in  1850,  during  some  researches  on  the  cartilaginous 
fishes,  served  to  throw  a  more  general  light  upon  these  mysterious  forms. 

"  In  the  gaU-bladder  of  a  Squatina  Angelas  there  occiuTed  in  the  bile,  and 
in  large  quantity,  peculiar  forms  of  various  organization,  but  which  were 
manifestly  developmental  forms  : — 1.  Rounded  vesicles,  consisting  of  a  delicate 
membrane  and  a  consistent  fluid ;  the  latter  was  of  a  yellow  colour,  and  con- 
tained a  multitude  of  also  yellow  granules.  2.  Other  vesicles  presented,  be- 
sides these,  other  elements  of  a  new  kind :  in  the  middle  of  the  granular 
contents  were  several  perfectly  transparent  cellules  ;  smaU  vesicles  had  only 
one  of  these  cellules,  larger  ones  as  many  as  six.  3.  Other  parent  vesicles, 
again,  exhibited,  besides  their  membrane,  a  granular  contents  and  secondary 
vesicles,  containing  Psorospermia,  always  one  in  each  secondary  vesicle.  4. 
In  the  latter  form,  finally,  the  secondaiy  vesicle  had  attained  a  large  size, 
and  the  Psorosperm  floated  in  a  spacious  clear  chamber,  which  occupied  nearly 
the  whole  of  the  parent  cyst.  Besides  these  motionless  cysts,  there  were  nu- 
merous free  Psorospermia  in  the  bile. 

"  He  found,  upon  examination,  very  similar  things  in  other  fishes  of  the 


266  GENERAL  HISTORY  OF  THE  INFUSORIA. 

same  class, — as  in  Spmax  vulgaris,  ScylUum  Canicula,  Torpedo  Narhe,  and 
Baja  Batis,  in  which  the  Psorospermia  differed  from  the  more  usual  form,  in 
being  grooved  or  ribbed. 

"  It  was  very  remarkable  that  the  above- described  organisms  were  never 
met  vrith  in  any  other  part  or  tissue  of  the  body  than  the  gall-bladder  or 
biliary  duct. 

"  With  respect  to  the  nature  of  these  bodies,  Ley  dig  is  inclined  to  tliink 
that  the  cyst  should  be  regarded  as  belonging  to  the  family  of  the  Gregarince, 
and  that  the  Psorospermia  must  be  looked  upon  as  generically  analogous  to  the 
pseudo-Navicellai  which  have  been  observed  to  be  generated  within  the  Gre- 
gariiice. 

*'  The  question  next  arises,  as  to  the  existence  of  similar  Gregariniform  or- 
ganisms producing  Psorospermia  in  fresh-water  fishes.  Leydig  thinks  there 
is  reason  to  suppose  that  the  animalcule  discovered  by  Yalentin  in  the  blood 
of  Salmo  Fario  is  a  Gregarina.  Moreover,  John  Mliller  and  Leydig  have  ob- 
served two  or  three  ecaudate  Psorospermia  in  Leuciscus  Dohulst  enclosed  in  a 
cyst, — whence  it  might  be  supposed  that  secondary  cells  may  be  developed 
within  one  of  Valentin's  Haematozoa  after  it  has  been  conveyed  in  the  coui^se 
of  the  circulation  to  one  organ  or  another,  in  which  cells  Psorospermia  may 
originate.  With  the  growth  of  the  latter,  the  granular  contents  of  the  Gre- 
garinoi  gradually  disappear,  which  are  thus  transformed  into  cysts  filled  with 
Psorospermia.  Such  a  cyst  would  then  be  equivalent  to  a  Navicella-recei^- 
tacle." 

Prof.  Huxley,  in  his  Lectures  on  Natural  History  (Medical  Times,  1856, 
xxxiii.  p.  508)  has  the  follomng  account : — 

"  The  Psorospermia  are  pyriform  sacs,  frequently  provided  with  an  elon- 
gated, filiform,  motionless  appendage,  and  containing  two  or  foui'  clear  rounded 
bodies,  attached  side  by  side,  within  their  smaller  ends,  and  besides  these, 
as  Lieberkiihn  has  lately  pointed  out,  a  rounded  mass  of  plasma.  Under  fitting 
conditions,  the  Psorospermia  burst,  and  the  plasmatic  mass  emerges  as  an 
Amoebiform  creature.  The  sacs  in  which  the  Psorospermice  are  developed, 
on  the  other  hand,  can  be  traced  back  to  Amoebiform  masses  full  of  granules ; 
and  it  seems  a  legitimate  conclusion,  that  the  Psorospermia  are  the  pseudo- 
Navicellce  of  an  Amoebiform  Gregarina  or  Gregarinoid  AmoebaJ' 

SUBSECTION  II.— CILIATA. 
(Plates  XXIY.-XXXL) 

According  to  the  arrangement  we  have  adopted  (p.  200),  the  Ciliata,  as 
a  subsection  of  Protozoa,  are  divisible  into  two  groups : — 1.  Of  such  as  are 
mouthless ;  2.  Of  those  possessing  a  mouth.  The  former  group  constitute  the 
Astoma,  the  latter  the  Stomatoda. 

In  Ehrenberg's  system  the  Astoma  were  not  recognized ;  for  where  he  did 
not  find  a  mouth  in  any  ciliated  Polygasirica,  he  nevertheless  assumed  its 
existence,  supposing  that  from  its  minuteness,  or  some  other  cause,  it  merely 
escaped  observation.  This  procedm^e  was,  indeed,  rendered  necessary  by  the 
hypothesis  with  which  he  set  out,  of  their  polygastric  organization. 

It  must  be  admitted,  to  Ehrenberg's  credit,  that  recent  researches  have 
proved  him  right  in  assigning  a  mouth,  in  by  very  far  the  largest  number  of 
Ciliated  Protozoa,  contrary  to  the  assertions  and  opinions  broached  by  many  of 
the  most  eminent  microscopists  a  few  years  since.  Yet  there  is  a  limited 
number  of  mouthless  Ciliata,  independently  of  the  peculiar  family  repre- 
sented by   the   genus  Actinophrys,  placed  very  erroneously  in   the  family 


or  THE  PROTOZOA. CILIATA.  267 

Enchelia  by  Ehrenberg,  which  must  be  separated  not  only  from  Stomatoda, 
but  also  from  the  Ciliata.  This  separation  we  have  carried  out,  in  consti- 
tuting the  two  groups  Actinophryina  and  Acinetina,  intermediate  between 
Ehizopoda  and  Ciliata.  Excluding  these  veiy  remarkable  creatures,  the 
Ehrenbergian  families  comprehended  in  our  history  of  Ciliata  are  the  Peri- 
dinicea,  Dinohryina,  Vorticellina,  Ophrydina,  Enchelia,  Colepina,  Trachelina, 
Ophryocercina,  Aspidiscina,  Kolpodea,  Oxytrichina,  and  Euplota. 

Among  the  Traclielina  were  enumerated  those  very  simple  parasitic  beings 
which  late  observations  have  proved  to  be  moutliless,  and  are  referred  chiefly 
to  a  genus  Opalhia.  These  we  therefore  abstract,  and,  treating  Opalina  as  the 
type,  have  constituted  a  new  family,  Opalincea,  a  member  of  the  group  Astoma. 
In  connexion  with  this  we  have  placed  the  very  imperfectly  known  Peridinicea, 
although  some  recent  writers  seem  disposed  to  attribute  to  them  the  posses- 
sion of  a  mouth  and  digestive  apparatus.  The  organization  of  the  Dinohryina 
is,  if  possible,  still  less  understood ;  and  since  we  have  no  other  descriptions  of 
it  than  those  supplied  by  Ehrenberg,  we  shall  allow  it  to  be  mustered  with 
the  other  ciliated  families  named  in  the  large  group  of  Stomatoda. 

GeOIJP  a. AsTOMA,  ASTOMATOUS  OH  MoUTHLESS  CiLIATA. 

FAMILY  I.— OPALIN^A. 
(Plate  XXII.  46,  47.) 

Geneeal  Characters  and  Functiois^s. — This  family,  represented  by  the 
genus  Opalina,  consists  of  minute  miscroscopical  animalcules,  moved  by  vibra- 
tile  ciha  distributed  generally  over  the  body,  without  mouth,  of  an  oval  or 
oblong  compressed  figure,  living  parasitic  in  the  interior  of  larger  animals, 
upon  whose  juices  they  nourish  themselves.  Their  contents  consist  of  a 
finely-granular  substance,  hoUowed  out  into  a  small  number  of  vesicular 
spaces,  mth  no  contractile  poAver ;  extending  through  the  centre  is  an  elon- 
gated band-like  (Hgulate)  nucleus,  enclosed  by  a  definite  but  delicate  mem- 
brane, and  composed  of  a  homogeneous  finely- granular  substance.  In  two 
species,  0.  Planariarum  and  0.  uncinata  (XXII.  46,  47),  a  large  pulsating 
vascular  canal  is  found  ;  the  latter  species  is  also  fm-nished  mth  strong  hooks, 
whereby  it  efi'ects  its  attachment  to  the  intestinal  surface,  from  which  it  draws 
its  nutriment.  Propagation  takes  place  by  transverse  self- division,  and  also,  in 
the  opinion  of  a  few  observers,  by  germs  or  embryos.  The  OpaUna3  are  com- 
posed of  sarcode  enveloped  by  an  integument,  and  rapidly  imdergo  difliuence. 
In  several  species  the  existence  of  a  mouth  has  been  surmised, — for  instance, 
by  Ehrenberg  in  Bursaria  {Opalina)  JRanarum,  and  by  Dujardin  in  Opalina 
Lumhrici.  All  doubt  on  this  point  may  be  always  removed,  Stein  tells  us 
{op.  cit.  p.  181),  by  using  chemical  reagents,  such  as  alcohol,  acetic  acid,  or 
weak  solution  of  iodine,  which  destroy  the  fold,  and  prove  no  real  opening  to 
exist.  If  further  proof  were  wanted,  the  constant  absence  of  foreign  particles 
in  the  interior  might  be  adduced.  This  absence  of  a  mouth  afi'ords  evidence 
of  the  merely  transitional  nature  of  Opalincea ;  for  the  same  featiu'e  prevails 
in  the  case  of  embryos  produced  from  the  Acinetina,  &c. 

The  vesicles  or,  as  Dujardin  calls  them,  "  vacuoles,"  seen  in  greater  or  less 
number  in  all  the  Opalincea,  are  irregularly  disposed  in  the  interior,  and, 
according  to  this  author  and  Stein,  have  no  limiting  membrane.  However 
this  may  be,  they  remain  clear  and  transparent  when  the  rest  of  the  contents 
are  coloured  by  the  bile  of  the  animals  the  Opcdina3  inhabit.  This  fact, 
moreover,  attests  another,  Aiz.  that  they  cannot  owe  theii'  formation  to  fluids 
received  from  without,  but  that  it  must  depend  on  the  pecuhar  properties  of 
the  contents  themselves.     The  formation  of  vacuoles  in  Opcdina?  was  adduced 


268  GENERAL  HISTOKY  OF  THE  INFTJSOfilA. 

to  disprove  the  origin  of  the  alimentary  globules  in  the  Ciliata  generally  by 
the  introduction  of  liquid  from  without ;  but  it  is  to  be  remembered  that  in 
these  two  groups  of  organisms  we  have  very  different  structural  conditions, 
and  that  in  the  CiKata  the  entrance  of  water  mostly  holding  solid  particles 
in  suspension,  through  the  oesophagus,  and  the  moulding  of  it  into  a  more 
or  less  spherical  outline,  are  matters  sufficiently  proved  by  direct  observation. 
We  have  stated  above,  that  the  vesicles  are  not  contractile ;  Dujardin  has, 
however,  described  those  of  Leucophrys  striata  as  irregularly  so. 

The  cilia  are  disposed  in  longitudinal  lines,  and  in  some  instances,  where 
there  are  ridges  or  margins,  present  a  greater  length  and  thickness,  as,  for 
instance,  upon  the  edges  of  the  ciu'ved  surface  by  which  the  0.  Planariai'um 
adheres. 

The  suiface  can  throw  itself  into  plaits  or  folds, — an  occurrence,  however, 
probably  limited  to  animals  in  a  diseased  or  dying  state,  as  Perty  remarks  in 
speaking  of  Opal'ina  Eanarum  (op.  cit.  p.  156). 

The  Opalincea  are  not  very  active ;  they  swim  onwards,  moving  at  the  same 
time  in  an  oscillating  manner. 

The  above  account  comprises  all  that  can  be  stated  of  the  Opalincea  gene- 
rally, since  the  differences  in  internal  structure  among  the  several  reputed 
species  are  so  great,  that  it  constitutes,  as  Stein  points  out  {op.  cit.  p.  182), 
a  strong  argument  against  the  existence  of  the  family  as  a  group  of  inde- 
pendent beings.  However,  from  the  study  of  the  peculiarities  of  the  several 
members  of  the  admitted  genus  Opalina,  this  author  reduces  them  to  three 
types,  viz. : — 1.  The  most  common  form  of  Opalina,  represented  by  the 
Leucophrijs  striata  of  Dujardin,  has  an  oblong  body,  marked  by  some  35  longi- 
tudinal granular  striae,  and  contains  a  number  of  vacuoles  var}ing  according 
to  external  conditions,  and  a  central  band-Hke  nucleus.  This  animalcule 
occurs  in  the  interior  of  the  common  earth-worm  (Lmnbriciis).  Stein  found 
them  of  different  lengths  from  1-60'"  to  1-14'",  and  in  all  stages  of  the 
process  of  transverse  fission.  "WTien  placed  in  water,  they  become  more  active. 
2.  The  second  form  differs  from  the  preceding  by  the  in-egular  distension  of 
the  body  when  placed  in  water :  a  strong  endosmotic  cuiTents  sets  in  through 
the  enclosing  waU  and  raises  it  from  its  contents,  so  that  these  at  length  pro- 
duce the  appearance  of  a  smaller  Opalina  enclosed  within  a  large  one.  Du- 
jardin has  described  this  variety  under  the  name  of  LeucopTirys  nodulata. 
This  Stein  would  imite  with  the  first  named,  under  the  term  of  Opalina  Lum- 
brici,  which,  indeed,  Schultze  applied  to  the  same  animalcule.  3.  The  third 
modification  of  Opalina  might  be  treated  as  an  independent  species ;  for, 
notwithstanding  a  general  resemblance,  it  has  a  striking  pecuharity  of  its 
own,  visible  under  a  strong  magnifying  power  (such  as  100  diameters),  in  the 
shape  of  a  single,  strong,  homy  apparatus,  placed  near  the  anterior  end  on 
the  flat  abdominal  surface  of  the  animal  (XXII.  47).  From  a  short  common 
base  situated  to  the  right  of  the  median  line,  slightly  cui^ed,  uncinate, 
pointed  processes  are  given  off,  of  which  one  is  much  longer  and  stronger 
than  the  other.  To  the  left  of  this  organ  a  fold  or  furrow  occurs  in  the 
surface,  which  might  be  mistaken  for  the  entrance  to  a  mouth.  The  deve- 
lopment of  this  organ  may  be  readily  followed  during  self- division.  It 
appears  first  as  a  homy  protuberance  close  to  the  line  of  section  (XXII.  47), 
which  extends  backwards  into  the  base  of  the  process,  and  forwards  or  up- 
wards into  the  two  hooks.  It  is  also  worthy  of  notice,  that  generally  a  greater 
or  less  number  of  solid  oval  nucleoli  and  short  rod-like  bodies  make  theii' 
appearance  within  the  homogeneous  substance  of  the  nucleus.  The  Opalina 
Lumhrici  of  Dujardin  is  no  other  than  the  animalcule  described,  although  its 
characters  are  incoiTectly  represented  by  that  author,  who,  from  his  figure, 


OF  THE  PROTOZOA.— opalin.5:a.  269 

has  evidently  seen  a  specimen  which  has  very  recently  completed  the  act  of 
self-fission  and  not  yet  reacquired  its  rounded  posterior  extremity.  The 
dark  stiipe  shown  at  the  fore  part,  and  supposed  to  indicate  a  mouth,  repre- 
sents the  uncinate  apparatus  above  described.  Stein  would  call  this  form  of 
Opalina  the  0,  armata,  and  regard  it  as  a  further  stage  of  development  of 
his  so-called  0.  Lumhrici. 

This  view  is  supported  by  the  fact  that  he  has  never  met  with  j^oung 
individuals  of  0.  armata  ;  for  all  the  specimens  he  encountered  were  of  a  nearly 
equal  size,  and  larger  than  the  largest  of  0.  Lumhrici,  in  company  with 
which  young  beings  are  very  common.  Thus  0.  armata  attains  a  length  of 
1-12'"  to  1-9'",  and  0.  Lumhrici  of  not  more  than  1-14"' ;  even  the  products 
of  fission  of  the  former  are  from  1-16"'  to  1-14'". 

**  If  now  it  be  considered  that,  excepting  the  horny  process,  not  the  least 
difference  in  structure  exists  between  0.  Lumhrici  and  0.  armata,  it  is  ren- 
dered very  probable  that  the  latter  is  merely  a  fui'ther  stage  of  development 
of  the  former.  If  this  be  the  case,  a  subsequent  more  considerable  meta- 
morphosis of  0.  armata  may  be  presumed,  when  it  becomes  transferred  to  a 
more  favourable  habitat,  as  happens  when  the  worm  it  inhabits  becomes  the 
food  of  some  other  animal.  I  have  not  actually  seen  Opalina  armata  adhering 
to  the  surface  of  the  intestine,  for  I  have  always  found  it  amidst  the  undi- 
gested mineral  and  organic  fragments  which  fill  the  alimentaiy  canal  of  the 
earth-worm.  Hence  it  is  more  likely  that  the  adhesive  organ  is  destined  to 
subsequently  fix  the  Opalina  in  a  more  permanent  manner." 

The  long  pulsating  vessel  seen  in  Opalina  Planariarum  and  in  0.  uncinata 
deserves  particular  notice,  by  reason  of  its  peculiaiity.  Stein  has  described 
it  in  the  first-named  species,  where  it  extends  the  entire  length  of  the  ani- 
malcule, as  bounded  by  a  definite,  delicate,  structiu'eless  membrane,  and  to 
be  without  the  outlets  Schultze  imagined.  It  contains  a  clear  liquid  like 
water,  which,  by  its  rhythmical  movements,  it  forces  to  and  fro  -within  it. 
On  killing  the  animal  with  alcohol,  the  walls  of  the  vessel  are  rendered  very 
evident.  It  becomes  divided  through  the  centre  in  the  act  of  self- fission,  and 
is,  in  Stein's  opinion,  not  homologous  with  the  contractile  vesicles  of  the 
Ciliata. 

Ntjclfxs.  Self-divtsiox.  Supposed  Embryo. — The  nucleus  is  a  very  evident 
organ  in  all  the  Opalincea,  with  the  single  exception  of  0.  Ranarum,  in  which 
Stein  has  sought  for  it  in  vain  among  multitudes  of  specimens  and  by  the  aid 
of  various  reagents.  In  this  same  exceptional  species  it  is  also  to  be  noted 
that  he  never  vidtnessed  the  act  of  fission,  yet  Siebold  ("  Ueher  Monostomum,'' 
Wiegmann's  Arcliiv,  1835)  described,  in  an  Opalina  living  as  a  parasite  in 
the  intestines  of  a  frog,  the  existence  of  a  number  of  smaU  embryos  within 
a  ca\'ity  of  the  posterior  extremity  of  the  body :  whether  this  animalcule, 
however,  was  the  Opalina  Ranarum  does  not  appear  ;  for  the  peculiar  habitat 
does  not  by  any  means  prove  such  to  be  the  case. 

A  contrast  occurs  in  the  Opalina  Branchiarum,  where  the  nucleus  which 
lies  in  the  axis  of  the  body  has  the  same  figure  as  the  entire  being,  and  one- 
half  its  dimensions.  Even  among  examples  of  the  same  species  the  position 
of  the  nucleus  varies  exceedingly.  Simultaneously  with  the  appearance  of  a 
constriction  in  the  general  figure,  the  nucleus  shows  signs  of  approaching 
fission  ;  but  ere  this  is  manifested  it  assumes  a  central  position  (whatever  may 
have  been  its  previous  one),  so  that  each  of  the  two  future  segments  may 
acquire  an  equal  section  of  it.  Moreover,  it  would  appear,  in  some  cases  at 
least,  that  the  constriction  and  scission  of  the  body  advance  more  rapidly  on 
one  side  than  on  the  other  of  the  animal. 

According  to  Stein,  the  production  recorded  by  Schultze  (Beifrdge  zur  Natur- 


270  GENERAL  HISTOET  OF  THE  INFT7S0EIA. 

gescMchte  cler  Turhellarien,  1851,  p.  67),  of  a  granular  germ-mass  in  Ojmlina 
Planariarum,  at  the  posterior  extremity  of  the  animalcule,  was  nothing  more 
than  the  act  of  fission  misconceived.  The  granular  contents  of  the  nucleus 
(says  Stein)  are  finer  or  coarser  in  the  animals  iiTespective  of  their  size  ;  and 
the  supposed  germinal  masses,  as  the  figiu^e  given  shows,  were  merely  the 
segments  of  the  nucleus  in  process  of  di\ision,  and  not  illustrations  of  the 
ulterior  development  of  that  organ  into  other  beings.  Schultze  witnessed 
this  process  but  once,  in  a  specimen  he  named  Opalina  polymorplia,  but  which 
was  the  same  as  the  0.  Flanariarum  of  Siebold  and  Stein. 

Habitats,  Vital  Endowments,  &c. — As  stated  before,  the  Opalincea  are  pa- 
rasites of  various  animals,  the  most  common  of  which  are  frogs,  newts,  and 
other  Batrachia,  earth-worms  {Lumhrici),  some  shell-fish,  as  the  Anodon  and 
the  common  muscle  {Mytilus  eduUs),  and  of  Planarke  and  several  Entozoa. 
They  are  found  in  the  intestines  in  the  earth-worm,  in  the  rectum  and  bladder 
in  the  frog,  among  the  ciha  of  the  tongue  of  that  reptile,  or  among  those  of 
the  gills  in  the  shell-fish,  &c. 

As  a  memorandum  touching  the  vital  properties  of  Opalincea,  we  may  quote 
here  an  experiment  made  by  Kolliker  on  the  vitality  and  development  of  the 
spermatic  filaments  {J.  M.  S.  1855,  p.  298)  : — ''  The  OpcdiiKB  move  in  a  solu- 
tion of  common  salt  of  1  per  cent.,  and  of  phosphate  of  soda  of  the  strength 
of  from  5  to  10  per  cent.  In  a  solution  of  salt  of  5  per  cent.,  and  of  sugar  of 
from  10  to  15  per  cent.,  they  shrink  up  and  become  quiescent,  though  re\'iving 
upon  the  addition  of  water.  I  have  even  succeeded  in  reviving  the  Ojpalince  after 
they  had  been  treated  vnXh.  a  solution  of  common  salt  in  the  proportion  of 
one-tenth." 

Nature  of  Opalin-f:a. — The  observations  of  microscopists  in  general  concui' 
to  prove  that  these  simple  beings  are  not  independent,  but  the  mere  embry- 
onic or  transitional  phases  of  other  animals.  This  opinion  was  put  forward 
by  Schultze,  and  has  been  seconded  by  Agassiz,  Stein,  and  others. 

Agassiz  asserts  (Silliman's  American  Journal,  1853)  that  the  deficient  Hnk 
in  Steenstrup's  history  of  the  succession  of  alternate  generations  of  Cercaria, 
and  its  metamorphosis  into  Distoma,  is  supplied  by  his  discovery  that  a  ge- 
nuine Opal'um  is  hatched  from  the  eggs  of  Distoma.  Stein  coincides  also  in 
considering  them  metamorphosed  into  Vermes,  and  states  that  Steenstrup  has 
watched  the  transformation  of  Leuwjyhrj/s  anodonta  (Ehr.)  into  an  intestinal 
worm.  He  saw  first  that  the  cilia  vanished,  that  they  fixed  themselves,  and 
became  by-and-by  changed  into  oval  motionless  bodies,  which  continued  to 
grow,  and  formed  an  internal  space,  within  which  a  germinal  mass  was  de- 
veloped, out  of  which  Cercaria  originated. 

Affinities  and  Classification  of  Opaline: a. — Upon  this  head  the  first 
point  is  to  settle  what  genera  and  species  are  to  be  numbered  with  the  Opali- 
ncea.  For  our  part  we  are  chsposed  to  place  in  this  family  all  Cihata  which 
are  mouthless,  andAvhich  lead  a  parasitic  life.  As  already  noted,  the  absence  of 
a  mouth  is  indicative  of  an  embiyonic  character,  an  indication  strengthened, 
if  not  confirmed,  by  observation  ;  consequently  this  group  of  beings  is  at  best 
but  provisional,  serving  only  the  purposes  of  definition  and  nomenclature, 
until  science  shaU  be  enabled  to  indicate  the  particular  animals  into  whose 
cycle  of  life  they  severally  enter. 

Furthermore,  we  have  seen  that  some  reputed  species  are,  in  all  probability, 
only  drfferent  stages  of  existence  of  the  same  Opalina, — for  instance,  the  0. 
armcita  a  more  adult  state  of  0.  Lumhrici.  And,  again,  the  stnictural  differ- 
ences between  0.  iincinata  and  0.  Planariarum  (consisting  in  the  possession 
of  a  singular  pulsating  vessel)  and  the  rest  of  the  group  are  so  stiiking,  that 
they  can  scarcely  be  rightly  included  in  one  genus. 


OF  THE  PROTOZOA. OPALIN.EA.  271 

On  turning  to  the  systematic  descriptions  of  various  writers,  we  find  much 
discrepancy  in  detail,  and  much  difference  in  opinion,  respecting  both  the 
species  to  be  counted  among  Opalincea  and  their  generic  distribution. 

The  family  '  Leucophryens '  of  Dujardin,  and  the  CobaUna  of  Perty,  severally 
include  most  of  the  species  which  we  would  reckon  as  Opalincea.  These,  in 
Ehrenberg's  system,  were  scattered  through  several  genera, — the  majority, 
however,  being  comprised  in  his  genus  Bursaria.  Stein  points  out  three  prin- 
cipal modifications  of  form,  but  is  not  prepared  to  constitute  them  into  genera. 

In  the  classification  adopted  by  the  three  first-named  writers,  the  Opalincea 
were  accounted  ordinary  Ciliated  Protozoa.  Perty  and  Dujardin  so  far  re- 
cognized their  peculiarities  as  to  erect  them  into  a  distinct  family.  Siebold 
went  ftiriher,  and,  on  account  of  the  absence  of  a  mouth,  placed  them,  with 
Astasia^a  and  Peridinicea,  among  the  Astoma.  We  coincide  with  Siebold  in 
thus  more  completely  separating  them  from  the  stomatodous  Ciliata  than  the 
other  authors  named,  but  at  the  same  time  look  upon  them  as  more  nearly 
allied  ^vith  Ciliata  than  with  either  Peridinicea  or  Astasicea,  and  consequently 
prefer  to  treat  the  Opcdinoia  as  a  subgroup  of  those  Protozoa. 

Neither  the  intimate  stnicture,  nor  the  developmental  histoiy  of  the  Opa- 
lincea, is  sufficiently  well  understood  for  them  to  be  arranged  in  well-defmed 
genera ;  nevertheless,  as  both  Dujardin  and  Perty  have  each  essayed  a  sy- 
stematic distribution,  it  behoves  us  to  set  their  schemes  before  the  reader. 

Dujardin  divides  the  Leucophryens  into  three  genera,  viz.  Spathidium, 
Leucophrys,  and  Opcdina.  Besides  these,  he  has  other  mouthless  genera  in 
his  family  Ploesconiens,  viz.  Diophrys  and  Coccudina,  maiine  but  not  parasitic 
animalcules ;  also  a  genus  Trochilia  without  distinct  mouth,  also  marine  in 
habit,  located  in  the  family  Erviliens ;  and  last,  the  genua  Plagiotoma,  among 
the  Bursariens,  parasitic  in  habit,  and  supposed  to  have  a  mouth  situated  at 
the  bottom  of  a  fossa,  but  which  contained  no  foreign  matters,  and  could  not 
be  fed  artificially  with  colouring  matter.  Of  these  genera  Coccudina,  Dio- 
phrys, and  Trochilia  are  imperfectly  kno^vn,  particularly  the  two  last,  and 
the  absence  of  a  mouth  cannot  be  predicated  of  them  with  any  certainty, — 
whilst  of  the  last  named  {Plagiotoma)  the  balance  of  evidence  is  against  the 
existence  of  a  mouth,  and,  as  we  shall  see,  this  genus  is  a  member  of  Perty's 
family  Cohcdina,  and  has,  moreover,  in  Stein's  opinion,  no  claim  to  rank  as  a 
distinct  genus. 

The  parasitic  family  Cohcdina,  Perty,  comprises  the  genera  Alastor,  Plagio- 
toma, Leucophrys,  and  Opcdina.  The  characters  of  these  several  genera,  placed 
by  observers  among  the  Opcdincea,  or  some  parallel  group,  together  with  their 
mutual  relations  and  differences,  will  be  fuUy  treated  of  in  the  systematic 
section  of  this  work. 

FAMILY  II.— PERIDINI^A. 
(Plate  X.  224-226;  XXXI.  16-23.) 

This  family,  in  Ehrenberg's  classification,  comprehended  four  genera,  viz. 
ChcetotypJda,  Chcetoglena,  Peridinium,  and  Glenodinium ;  but,  as  Dujardin 
rightly  judged,  the  two  first  genera  belong  rather  to  the  Cryptomonadina,  by 
being  destitute  of  the  ciliary  furrow,  the  leading  characteristic  of  the  Peri- 
dinicea. Our  description  ^viU  therefore  particularly  apply  to  the  two  other 
genera,  Peridinium  and  Glenodinium. 

The  beings  imder  consideration  have  received  little  attention  from  natu- 
rahsts,  and  are  stiU  imperfectly  imderstood.  Indeed,  we  feel  that  no  sufficient 
data  are  at  hand  whereon  to  ground  an  opinion  relative  to  their  true  position, 
nature,  and  affinities.     We  place  them  here  as  a  supplementary  group  of 


272  GENERAL  HISTORY  OF  THE  INFUSORIA. 

Ciliated  Protozoa,  fii'st,  because  of  their  wreath  or  general  clothing  of  cilia — a 
phenomenon  seen  among  none  of  the  Phytozoa  or  Plagellata,  which  have  never 
more  than  one  or  two,  or,  rarely,  four  filaments  or  flabella  ;  and  secondly,  be- 
cause every  author  who  has  described  them  treats  them  as  animalcules. 
Perty,  although  recognizing  them  as  animals,  nevertheless  groups  them  with 
his  Phytozoidia,  probably  omng  to  their  bizarre  form  and  to  the  characteristic 
internal  organization  of  CiHata  not  being  perceptible.  Siebold,  on  the  con- 
trary, places  them,  together  with  Euglenwa  and  Opalincea,  among  the  asto- 
matous  or  mouthless  Protozoa. 

Ehrenberg's  description  of  the  Peridinicea  is  as  follows  : — The  animalcules 
of  this  family  are  polygastric,  but  have  no  alimentary  canal ;  the  mouth  is 
usually  found  in  a  depression  near  the  middle,  and  from  its  vicinity  a  delicate 
filament  (proboscis)  is  given  ofi'  in  three  of  the  genera.  They  are  clothed 
with  a  shell  or  lorica,  having  a  transverse  furrow  or  zone  occupied  with  a  row 
of  vibratile  ciha  ;  and  besides  this  wreath,  several  species  have  also  fine  setae 
or  cilia  scattered  over  them.  In  Peridinium  acuminatum,  P.  fulvum,  and  P. 
(  Ceratium)  cornutum  the  digestive  sacs  are  visible  without  recourse  to  artificial 
means  ;  but  in  P.  Pulvisculus  and  P.  cinctum  those  organs  can  be  demonstrated 
only  by  the  use  of  coloui-ed  food,  chiefly  because  they  are  hidden  by  the 
clusters  of  ova,  to  which  the  colour  of  the  animalcules  is  due.  This  is  com- 
monly red,  yellow,  or  brown,  and  rarely  green.  In  Peridinium  Tripos  and  P. 
Fusus  a  seminal  gland  (nucleus)  is  visilDle,  and  in  Chcetoglena  and  Glenodinium 
a  red  eye-speck.  Longitudinal  self-division  has  been  observed  in  P.  Pulvisculus 
and  P.  Fusus. 

Dujardin,  unable  to  accept  these  views  of  their  organization,  described  the 
'  Peridiniens '  as  "  animals  without  known  internal  organs,  enveloped  by  a 
definite  resistant  membranous  lorica,  which  sends  ofi'  a  flagelliform  filament, 
and  has,  in  addition,  one  or  more  furrows  beset  with  vibratile  cilia.  The 
lorica  would  appear  to  have  no  orifice,  since  foreign  particles  and  colouring 
matters  cannot  enter  it ...  .  The  members  of  this  family  are  distinguished 
from  Thecamonadina  by  the  ciliated  furrow  or  furrows." 

Further,  Dujardin  ignored  the  red  stigma  as  a  generic  distinction,  and  in 
this  is  followed  by  Perty.  Ehrenberg  created  a  subgenus  of  Peridinium  for 
those  species  which  have  the  lorica  prolonged  into  hom-like  processes,  under 
the  name  of  Ceratium.  Both  Dujardin  and  Perty  retain  this  appellation,  but 
would  elevate  the  group  comprehended  under  it  to  the  rank  of  a  genus. 

Let  us  now  proceed  with  a  resume  of  the  facts  at  present  received  respect- 
ing the  organization  and  habits  of  the  Peridinio'.a. 

The  lorica  is  double,  consisting  of  an  outer,  more  or  less  firm,  non-contrac- 
tile layer,  and  an  inner,  homogeneous,  hyaline  membrane  :  usually  a  space 
occurs  between  the  two  coats ;  but  in  Glenodinium  they  are  in  close  apposi- 
tion— a  double  contour,  however,  being  perceptible.  The  inner  layer  may 
be  taken  to  represent  the  primordial  utricle ;  it  immediately  envelopes  the 
contents,  which  consist  of  a  homogeneous  protoplasm,  enclosing  within  itself 
numerous  globules,  granules,  and  vesicles.  In  the  case  of  the  smallest  Peri- 
dinicea, such  as  P.  Pulvisculus,  P.  monadicum,  and  P.  Corpusculum,  the  di- 
stinctness of  envelope  from  contents  ceases,  and  when  in  a  dying  condition  the 
whole  figure  undergoes  a  great  variety  of  changes — a  fact  indicating  a  less 
perfect  development  of  the  lorica — and  there  is  a  rapid  breaking  up  of  the 
contents.  In  the  larger  species  the  outer  tunic  is  more  elaborated,  and  either 
displays  a  minute  cellular  or  reticulate  structure,  or  appears  quite  smooth  and 
structureless,  although  firm  and  resistant  (as  in  Glenodinium  cinctum).  A 
cellular  lorica  occurs  in  Ceratium,  and  also  in  various  Peridinia,  which  Perty 
separates  from  the  rest,  under  the  name  of  Glenodinium,  by  reason  of  this 


OF  THE  PROTOZOA. PERIDINI.EA.  273 

structure.  This  external  tunic  is  decomposable,  although  it  resists  destruc- 
tion much  longer  than  tlie  contained  matters ;  and  it  is  esi3ecially  after  a 
certain  amount  of  change  has  proceeded,  that  its  delicate  retiform  structure 
is  more  distinctly  exhibited. 

The  figiu'e  of  Peridinicea  is  very  various  and  bizarre  :  the  simplest  is  that 
of  a  spheroid  divided  into  two  segments,  equal  or  unequal  in  size,  by  a  trans- 
verse ciliated  fiuTOW  or  zone.  In  some  instances  one  side  is  flatter  and  concave, 
and,  according  to  Perty,  presents  a  wide  opening,  or  elongated  fissure  (XXXI. 
16),  from  which  the  filament  may  sometimes  be  seen  to  proceed.  Moreover, 
besides  the  transverse  furrow,  a  second  is  seen  in  some  species  to  proceed  from 
it  at  right  angles,  as  far  as  the  vertex  of  the  anterior  half, — as,  for  example,  in 
Dr.  Allman's  species  Peridinium  uberrimimi  (XXXI.  16, 18),  and  in  P.  fuscum 
and  P.  ocidatum  {Glenodhiium  cinctum,  Ehr.).  Indeed,  in  Glenodinium  apicu- 
latum  Ehrenberg  describes  several  subsidiary, shalloAver, hispid  furrows  branch- 
ing over  the  surface  (X.  224-226),  and  in  G.  tahidatum  a  series  of  non-hispid 
lines  or  ridges.  These  last  two  forms  recall  in  general  features  the  pollen-cells 
or  grains  of  the  higher  plants,  and  may,  indeed,  from  the  deficiency  of  a  loco- 
motive filament,  and  from  other  exceptional  characters,  be  considered  doubtful 
members  of  the  family  Peridinicm.  An  inequality  of  the  two  segments,  as 
separated  by  the  ciliary  zone,  is  seen  in  Peridinium  Corpuscidum  and  P.  mo- 
nadicum,  and  in  a  less  degree  in  P.  ocidatum  {Glenodinium  cinctum).  The 
figure,  however,  is  very  curiously  and  materially  altered  by  the  production  of 
tapering  or  horn-like  processes,  of  a  large  diameter  and  great  length  relatively 
to  the  principal  portion  or  body  of  the  organism.  These  processes  difter  in 
number  in  diiferent  species,  and  give  rise  to  very  bizarre  forms,  dej^arting 
widely  from  those  of  any  Phytozoa  or  from  any  other  ciliated  Protozoa.  The 
number  of  horns  in  Ceratium  Fusus  is  two,  and,  being  in  the  same  line,  produce 
the  spindle-shaped  figure  of  the  entii^e  being  (X.  222,  223).  In  C.  furca 
two  occur  in  front  and  one  of  larger  dimensions  beliind  ;  the  same  is  seen  in 
P.  Tripos  (X.  219,  220),  in  which,  however,  the  two  anterior  processes  are 
curved, — whilst  P.  cornutum  {Ceratium  HirundineUa)  has  from  two  to  three 
posteriorly,  and  one,  usually  curved,  anteriorly.  In  Ceratium  Micliaelis  (X. 
221),  again,  we  see  three  short  processes  project  from  the  posterior  half ;  and, 
lastly,  in  C.  macroceras  (Perty)  three  are  represented  behind,  of  which  the 
central  is  much  the  longest  and  straightest,  and  in  front  one  still  longer  but 
rather  curved.  The  length  of  the  horns  compared  with  the  body  of  the  Ce- 
ratia  affords,  however,  no  specific  character,  inasmuch  as  it  varies  according 
to  age  and  probably  also  other  conditions.  The  vibratile  cilia  are  usually  con- 
fined to  the  groove  surrounding  the  lorica,  and  to  the  direct  continuations 
from  it.  Nevertheless  Dr.  AUman  discovers  in  P.  uberrimum  the  whole  sur- 
face sparsely  covered  with  them ;  and  Ehrenberg  mentions  the  supplementaiy 
farrows  of  Glenodinium  apiculatum  as  occupied  with  hispid  hairs  (X.  224- 
226).  The  locomotive  filament,  which  Ehrenberg  failed  in  seeing  in  all  even 
of  his  genus  Peridinium,  is  usually  of  great  length  and  tenuity,  and,  accord- 
ing to  the  great  Berlin  micrographer,  proceeds  from  the  neigh boiu-hood  of  the 
mouth  which  he  believed  he  detected  in  Peridinium  Fusus  in  a  hollow  near 
the  middle  of  the  animalcule.  Allman  more  definitely  points  out  its  situation 
as  being  near  the  junction  of  the  transverse  and  vertical  furrows  in  the  species 
he  has  described  (XXXI.  16).  Lastly,  Perty  states  that  Ceratium  HirundineUa 
{C.  cornutum,  Ehr.),  when  swimming,  stretches  out  the  filament  as  if  stifi",  and 
that,  although  2^  times  longer  than  the  body,  it  may  be  easily  overlooked,  on 
account  of  its  active  swinging  movement.  It  is  apparently  a  production  of  the 
protoplasm,  protmded  externally  through  an  apertiu'e  in  the  investing  tunics. 
Opinion  is  divided  respecting  the  existence  of  a  mouth.     Ehi-enberg  repre- 


274  GENERAL  HISTOEY  OF  THi;  IIM  L.-SOlcIA. 

sented  one,  and  also  the  possible  admission  of  coloured  food,  but  was  contra- 
dicted by  Dujardin,  who  denied  both.  Siebold  reckons  Peiidinicea  among 
mouthless  Infusoria  {Astoma).  Perty  mentions  the  fossa  in  the  shell,  but  no 
aperture ;  and  Allman  remains  silent  on  the  matter.  On  the  other  hand,  Lach- 
mann  admits  its  presence,  and  thus  discusses  the  mode  of  reception  of  food 
(J..iV^.ir.l857,  vol.  xix.  p.  220)  :— "Prom  the  point  of  insertion  of  the  flagel- 
lum,  on  one  side  the  large  notch,  in  the  upper  part  of  the  row  of  cilia,  a  clear 
canal  passes  into  the  body  of  the  animal,  and  dilates  at  the  extremity  to  form 
a  cavity  of  variable  diameter.  The  flagellum  is  often  seen  to  contract  rapidly 
into  a  spiral  form,  and  apparently  disappear ;  and  not  unfrequently  we  may 
then  succeed  in  perceiving  that  it  is  jerked  back  into  the  above-mentioned 
cavity,  from  which  it  soon  retui^ns  into  its  previous  position.  Now  it  cer- 
tainly appears  worth  while  to  see  whether  small  particles  of  food  are  not 
carried  into  the  cavity  by  this  jerking  in  of  the  flagellum." 

Contents. — These  may  be  divided,  as  in  the  Euglence,  into  minute  shapeless 
molecules,  and  globular  corpuscles  and  vesicles  with  red  stigma  and  nucleus. 
Sometimes  the  corpuscles  are  green,  and  resemble  chlorophyll,  but  more  fre- 
quently they  are  red,  yellow,  or  brown,  or  intermixtui'es  of  those  colours.  In 
the  earliest  stages,  indeed,  colour  is  absent,  and,  just  as  in  Euglencea,  only 
minute  moleculse  are  found  interspersed  in  the  colourless  protoplasm.  More- 
over, when  a  colour  appears,  it  may  not  simply  become  more  intense  or  darker 
by  age,  but  change  to  another  tint  belonging  to  the  same  series  of  colours. 

In  younger  specimens  again,  the  contents  more  completely  occupy  the 
entire  being,  whilst  frequently  in  old,  and  more  especially  in  specimens 
withering  or  dying,  they  become  contracted  into  a  ball,  placed  either  in  the 
centre  or  more  or  less  to  one  side  (excentric).  A  swelling  out  of  the  external 
tunic,  the  disappearance  of  the  red  stigma,  the  vibratile  cilia,  and  the  filament 
accompany  this  shrinking  of  the  cell- contents.  The  retrograde  change  in 
the  contents  is  further  manifested  by  the  appearance  of  a  large  vesicle  about 
the  centre,  or  of  several  dispersed  smaller  ones  at  that  or  in  other  parts. 
Some  at  least  of  these  vesicles  are  merely  oil- drops,  which,  as  Braun  shows 
in  his  essay  on  Rejuvenescence,  are  the  usual  concomitants  of  a  process  of 
destructive  assimilation.  After  the  destruction  of  the  cell- contents,  the  firm 
lorica  remains  hke  an  empty  shell,  boldly  displaying  its  sculpturing,  and  in 
many  instances  also  a  curved,  apparently  internal,  stripe  about  the  middle  or 
to  the  right  of  it,  which  Perty  presumes  to  be  either  the  Line  of  attachment 
of  the  contents  or  a  fold. 

Among  more  constant  structures.  Dr.  Allman  describes  a  central  nucleus — 
the  organ  probably  alluded  to  by  Ehrenberg  under  the  name  of  an  oval  semi- 
nal gland,  in  Peridinium  Trij>os  and  P.  Fusus.  AUman  describes  the  nucleus 
to  be  of  an  irregular  oval  form,  quite  colomiess,  and  marked  on  the  surface 
with  curved  striee  (XXXI.  20)  ;  under  pressure  the  envelope  gives  way,  and 
the  nucleus  escapes  with  the  other  contents.  A  contractile  vesicle  has  not 
hitherto  been  discovered.  One  or  more  large  clear  vacuoles  may  originate  in  the 
internal  substance  ;  but  such  have  not  the  pulsating  power  of  definite  vesicles. 

The  red  speck  or  stigma  (XXXI.  16, 17)  has  no  pretensions  to  the  nature 
of  a  visual  organ.  It  is  not  always  present  even  in  examples  of  the  same 
species ;  or  it  is  multiplied ;  and  it  is  known  also  to  disappear  v^ith  advancing 
age.  Again,  Perty  recounts  the  fact  of  the  diflPiision  of  the  red  colour 
of  the  speck  throughout  the  whole  contents,  at  times  leaving  a  narrow  ex- 
ternal ring  w^hich  retains  its  green  colour.  This  phenomenon  was  witnessed 
in  a  specimen  of  Olenodinium  cinctum.  In  young  individuals  of  Peridinium 
tahidatum,  which  are  of  a  light-green  colour  and  translucent,  there  is  no  trace 
of  a  red  speck ;  yet  Perty  met  with  a  collection  of  these  beings  of  apparently 


OF  THE  PROTOZOA. PEEIDINI^A.  275 

smaller  size  than  usual,  yellow  in  colour,  and  not,  like  older  animalcules, 
greenish-brown  or  brown,  which  had  from  10  to  12  red  vesicles  or  globules 
about  the  middle  of  the  anterior  segment.  Still  the  general  rule  is  that  in 
very  young  indi\iduals  no  stigma  is  present.  The  inconstancy  of  the  presence 
of  the  red  speck,  even  in  matiu-e  specimens,  its  absence  in  very  young,  its  dis- 
appearance in  old  ones,  and  the  many  irregularities,  not  only  in  its  occurrence 
but  also  in  size  and  number,  are  facts  which  sufficiently  prove  its  worthless- 
ness  as  a  generic  or  even  as  a  specific  distinction,  and  which  declare  against 
its  assumed  function  of  a  visual  organ  in  this  as  in  other  families  of  Protozoa. 

REPEonrcTioN. — Longitudinal  fission  has  been  seen  to  take  place  in  several 
species.  Self-di\T.sion,  says  Perty,  presents  many  peculiarities  among  the 
Pendinicea.  In  Ceratium  HirimdineUa,  fission  is  longitudinal ;  it  commences 
anteriorly  close  to  and  on  the  left  side  of  the  great  horn  (as  the  animalcule 
is  viewed  from  above),  and  advances  towards  the  posterior  extremity.  The  pro- 
cess is  not  confined  to  the  large  specimens,  but  is  equally  enjoyed  by  the  small. 

During  the  act  of  fission  in  Peridinium  Pidviscidus,  Perty  noticed  that 
before  its  completion  the  newly-formed  segment  continued  to  augment  in 
size  until  it  surpassed  the  original  being,  which  underwent  no  enlargement. 

Dr.  Allman  noticed,  in  the  species  he  examined  (J.  M.  S.  1854,  p.  25),  that 
spontaneous  division  took  place  "  parallel  to  the  annular  furrow  "  (XXXI. 
18),  i.  e.  therefore  transversely,  "■  and  in  the  unfurrowed  hemisphere."  He 
also  remarked  the  important  fact,  that  this  process  appears  to  be  invariably 
preceded  by  a  di\T.sion  of  the  nucleus ;  and  he  had  succeeded  in  isolating  nuclei 
presenting  almost  eveiy  stage  of  transverse  fission.  But  besides  their  reproduc- 
tion by  fission,  Perty  adopts  Ehrenberg's  \dews  and  insists  on  their  development 
from  ova  or  ovules,  which  present  themselves  in  the  form  of  brown  or  green 
corj3uscles  in  the  interior.  Peridinium  tahulatum  is  often  seen  to  be  full  of 
such,  elHptic  in  figure,  and  as  much  as  1-150'"  in  length,  and  which  can  be 
expelled  by  pressure  from  the  animalcule.  In  P.  Pidviscuhs  Perty  met  with 
specimens  from  1-400'"  which  were  aggregated  together  in  masses,  and  moved 
together.  In  P.  Oorpiiscidum,  he  asserts,  development  from  ovules  may  be 
directly  observed ;  and  he  gives  figures  of  ovules  set  free,  and  of  the  young 
generated  from  them,  which  would  seem  the  same  structures  with  the  addition 
of  a  cell- wall.  The  ovules,  too,  are  large  and  very  e\ddent  in  Ceratium  cornutum ; 
and  he  regards  the  small  brown  organisms  which  may  be  found  in  company  with 
mature  individuals  at  various  times  of  the  year,  as  the  primitive  stage  of  ge- 
neration of  those  ova  before  acquiring  the  perfect  figure  of  Ceratium.  In  some 
specimens,  indeed,  he  remarked  the  long  filament  peculiar  to  the  species,  and  a 
red  stigma  in  the  posterior  segment.  The  smallest  examples  measured  1-200'", 
and  were  at  first  elliptic ;  from  this  they  changed  to  reniform,  and  became 
distinguished  into  an  anterior  and  a  posterior  half.  Their  movement  was  ro- 
tatoiy  or  spiral,  and  quicker  than  in  old  individuals.  On  one  occasion  he  saw 
small  examples  of  Ceratium  Hirundinella  only  1-25'",  of  the  same  figure  as  the 
large  specimens,  but  completely  colourless  ;  at  another  time  he  encountered 
pale  brownish-green  individuals,  with  a  beautiful  red  stigma,  and  the  poste- 
rior lateral  horns  scarcely  developed, — whilst  in  one  instance  the  anterior 
cornu  was  completely  formed,  and  the  posterior  extremity  rounded.  These 
examples,  he  observes,  appear  to  be  different  structural  phases  through  which 
the  products  generated  from  the  ovules  have  to  pass. 

The  reproduction  by  ovules  or  internal  germs  has  its  parallel  in  Euglencea ; 
and,  like  as  in  this  group,  so  in  the  family  Peridinicea  a  quiescent,  resting,  or 
"  still  '*  stage  appears  to  occur.  Dr.  Allman  has  put  forward  this  fact  most 
clearly.  He  writes  (,/.  M.  S.  1854,  p.  24) — "  Before  death,  and  also  when 
passing  from  a  motile  to  a  quiescent  state,  most  likely  preparatory  to  under- 

T  2 


276  GENERAL  HISTORY  OF  THE  IXFL'SORIA. 

going  some  important  developmental  change,  the  contents  contract  towards 
the  centre ;  and  then  an  external  transparent  and  perfectly  colomiess  vesicle 
becomes  visible,  while  the  flagellum  and  cilia  disappear.  The  contracted 
contents  present  a  very  definite  and  general  spherical  boundary,  and  are  evi- 
dently included  in  a  distinct  cell " — the  primordial  utricle.  On  a  subsequent 
examination  of  the  pond  in  which  the  species  examined  occurred  in  prodi- 
gious quantity,  he  found  "  immense  masses  "  of  the  Peridinimn  "  towards 
the  bottom,  where  they  appeared  quite  healthy,  though  presenting  the  condi- 
tion described  above  as  characterizing  the  quiescent  state  of  the  animalcule." 

Our  imperfect  information  respecting  the  organization  of  the  Peridinicea 
renders  any  argimients  concerning  their  nature  unsatisfactory  and  inconclu- 
sive. Perty,  to  whom  we  owe  most  of  our  knowledge  respecting  these  crea- 
tures, agrees  mth  Ehrenberg  in  assigning  them  an  animal  nature  ;  and  we 
gather  from  the  few  remarks  Dr.  Allman  has  made,  that  this  opinion  has  also 
the  advantage  of  his  support.  Dujardin,  we  may  add,  treated  the  Peridinicea 
as  animalcules.  Of  the  opposite  opinion,  viz.  that  they  are  members  of  the 
vegetable  kingdom,  we  know  of  no  advocates,  although  some  facts,  such  as 
the  apparent  absence  of  the  known  internal  stnictui'e  of  the  Cihated  Protozoa, 
the  non-contractility  of  their  bodies,  the  character,  colour,  and  changes  of 
their  contents,  might  be  adduced  in  its  favour.  However,  the  force  of  those 
presumed  facts  will  be  much  lessened  by  the  consideration  that  the  internal 
organization  of  the  Cihata  may  yet  be  discovered  in  these  organisms  when 
they  receive  their  due  share  of  attention  from  microscopists,  that  even  the  ab- 
sence of  a  mouth  and  rudimentaiy  digestive  tube  would  not  absolutely  exclude 
them  from  the  animal  kingdom ;  and  that  in  the  form  and  character  of  their 
ciliary  armature  they  present  an  animal  much  more  than  a  vegetable  type. 

Of  their  Vital  Endowments,  we  may  state  that  some  swim  mth  consi- 
derable activity  by  means  of  their  flagellimi,  aided,  no  doubt,  by  their  ciliary 
wreath,  which  probably  gives  the  oscillating  and  rolling  character  to  their 
movements. 

They  are  inhabitants  both  of  salt  and  of  still  fresh  water,  among  aquatic 
plants,  but  not  of  infusions ;  and  they  disappear  from  water  when  long  kept. 
Most  of  the  genus  Peridinimn  are  marine.  They  may  occur  in  such  enormous 
multitudes  as  to  colour  the  pond  or  other  collection  of  water  in  which  they 
have  accumulated.  Of  this  phenomenon  Dr.  Allman  mentions  an  example 
in  which  his  Peridinimn  uberrimum  was  so  abundant  in  the  ponds  of  Phoenix 
Park,  Dublin,  as  to  colour'  the  water  brown : — "  This  colour  was  sometimes 
uniformly  diffused  through  the  water ;  at  other  times  it  appeared  as  dense 
clouds  varying  from  a  few  square  yards  to  upwards  of  a  hundred  in  extent." 
This  was  in  Jime  ;  in  July  "  the  coloration  of  the  ponds  had  much  increased 
in  intensity ....  The  colour  in  some  parts  was  of  so  deep  a  bro^svn,  that  a  white 
disk  half  an  inch  in  diameter  became  invisible  when  plunged  to  a  depth  of 
3  to  6  inches,  while  a  copious  exit  stream,  which  constantly  flowed  away 
from  one  of  the  ponds,  presented  the  same  deep-brown  tint." 

The  most  remarkable  vital  phenomenon  presented  by  the  Peridinicea,  and 
which  is  particularly  common  in  them  as  a  family,  is  that  of  phosphorescence, 
which  is  possessed  in  a  high  degree  by  several  of  the  marine  species,  having 
a  yellow  or  yellow-brown  colour.  In  nine  phosphorescent  drops  of  sea- water 
from  near  Kiel,  taken  up  one  after  another  by  Ehrenberg,  nothing  save  a 
single  individual  of  Pendinium  (Ceratiu7n)  Tripos  was  discoverable.  Besides 
this  species,  the  following  other  Ceratia  are  phosphorescent,  viz.  Ceratiuni 
Fusus,  C.  acuminatum,  C.  Michaelis,  and  C.  Furca. 

Ehrenberg  has  reported  the  occiuTence  of  fossil  Peridinicea  ;  but  the  or- 
ganisms so  considered  are  peculiar  in  having  a  silicious  shell,  which  renders 


OF  THE  PROTOZOA. 


277 


their  alliance  to  this  family  somewhat  doubtful.  They  are  met  with  in  chalk, 
the  only  secondary  stratum,  and  here  in  the  substance  of  flints ;  but  they 
also  occur  in  strata  of  later  formation.  Their  presence  in  flints  renders  it, 
indeed,  sujDposable  that  their  silicious  constitution  is  an  ulterior  result  of  the 
infiltration  of  silex  in  a  state  of  solution  into  the  texture  of  theii'  previously 
membranous  envelope.  They  are  found  in  company  with  fossil  Fyxidicula 
and  Xanthidia.  Ehrenberg  described  two  fossil  species  under  the  name  of 
Ceratium pyro^horum  and  C.  Delitiense. 

CILIATA. 

Grotjp  B. — Stomatoda. 

(Illustrated  by  Plates  XXIY.-XXXI.) 

The  animalcules  whose  general  history  we  have  noAv  to  write  are,  as  before 
mentioned,  comprehended  for  the  most  part  in  the  families  Dinohryina, 
Vort'wellina,  Ophrydina,  EncJielia,  Colejmia,  Trachelina,  Opliryocercina,  Aspi- 
discina,  Koljjodea,  OxytricJiina,  and  Euplota,  as  instituted  by  Ehrenberg,  with 
the  removal  of  the  OpaUncea  from  the  Trachelina,  and  of  the  Acinetina  and 
Actinopliryina  from  the  Enclielia. 

The  descriptions  of  the  beings  composing  these  several  families,  as  furnished 
by  Ehrenberg,  are  so  tinged  by  his  peculiar  views  of  organization  as  to  mar 
their  utility ;  and  therefore,  for  precision  and  accuracy  of  detail,  we  have  to 
rely  in  great  measure  on  the  observations  made  within  the  last  few  years, 
chiefly  by  German  naturalists.  Notwithstanding  the  jDersevering  industry 
•vvith  which  these  scientific  men  have  piu'sued  their  inquiries,  many  genera 
yet  remain  almost  imknown,  or  little  understood,  in  respect  to  their  structm-e, 
whether  internal  or  external. 

The  Ciliated  Stomatoda,  or  as  we  shall  more  briefly  style  them  the  Cihata, 
are  microscopical  animals  having  a  defijiite  limiting  membrane  or  external 
tunic  covered  more  or  less  completely  with  vibratile  cilia,  by  which  they 
swim ;  and  when  it  is  indurated,  as  not  unfrequently  happens,  it  is  further 
furnished  with  bristles  or  other  tegiunentary  appendages,  by  which  they 
are  capable  of  crawling  or  leaping.  They  aU  possess  a  more  or  less  di- 
stinct mouth,  which  opens  into  an  oesophagus  or  gullet,  continued  to  a  vari- 
able extent  into  the  interior  as  a  digestive  or  alimentary  tube,  but  ending 
abruptly  by  an  open  extremity.  In  many  genera  a  discharging  orifice  or 
anus  is  perceptible  ;  and  in  all  there  are  a  nucleus  and  one  or  more  contractile 
vesicles.  They  propagate  by  self-di\^sion,  by  gemmation,  and  by  internal 
germs  or  embryos,  with  a  greater  or  less  degree  of  metamorphosis,  and  they 
undergo  the  encysting  process :  the  act  of  gemmation  appears  limited  to  a 
few  genera  ;  but  self- fission  and  embryonic  development  may  be  predicated  as 
general  phenomena. 

Dimensions. — In  dimensions  aU  the  Cihata  are  microscopical ;  for  if  some, 
such  as  Spirostomum,  Stentor,  Opercidaria,  Zoothamnium,  Vayinicola,  and 
other  genera  of  Volvocina  and  Ophrydina  are  visible  to  the  naked  eye  as 
minute  specks  or  globules,  they  are  far  beyond  its  ken  for  any  purposes  of 
investigation,  and  are  therefore  essentially  objects  for  the  microscope.  Yet 
amid  these  hosts  of  equally  microscopic  beings,  the  range  in  point  of  size  is 
actually  as  great  as  that  between  the  dog  and  the  elephant  among  animals  cogv 
nizantto  our  ordinaiy  observation.  Even  among  members  of  the  same  genus, 
and,  indeed,  of  the  same  species,  their  dimensions  may  vaiy  within  limits 
extremely  wide.  To  quote  a  few  examples  :  Spirostomion  ambigimm  (Ehr.) 
has  a  length  of  ^th  of  an  inch ;  the  branching  polyparies  in  EpistyUs  and 
Opercidaria  reach   ith  in  height,  those  of  Zoothamnium  1th,  whilst  many 


278  GENERAL  HISTOKY  OE  THE  INEUSOBIA. 

stalked  VorticelUe  extend  themselves  to  y^th  in  length.  Paramecia  are  men- 
tioned by  Ehi'enberg  from  ^th  to  ^  ^\.  ^th  in  length  ;  and  specimens  of  the  same 
species  of  VorticeUa,  viz.  F.  microstoma,  are  described  to  vary  in  size  between 
2-gVo^^  ^^^  yio^^*  Stein  has  also  noticed  examples  of  Chilodon  CucuUulus 
from  2^0^^  ^^  TTUU^^-  ^  ^^®^  surprising  magnitude  is  attained  by  the  polypoid 
masses  of  Oplirydium  versatile,  which  range  between  mere  microscopic  globules 
and  aggregated  masses  the  size  of  the  fist  or  even  of  the  head  of  a  man. 

FiGUEE. — In  figure  the  Ciliata  exhibit  an  immense  variety,  but  have  a 
rounded  outline  in  all  instances.  The  prevailing  figure  is  oval  or  oblong  ;  but 
some  taper  much  at  one  or  both  ends,  and  acquire  a  spindle-,  or  a  flask-,  or  a 
club-shaped  aspect,  whilst  others,  as  the  VorticelUna  (XXVII.  1,  2,  4,  16; 
XXX.  1,  9,  11),  present  a  bell-shaped  or  campanulate  outline,  and  others 
again,  as  Spirostommn  (XXIV.  298),  an  elongate  ribbon-  or  band-like  one. 
However,  the  best  idea  of  the  manifold  forms  can  be  gathered  by  inspecting 
the  subjoined  plates  of  the  Ciliated  Protozoa,  which  render  verbal  description 
imnecessary. 

The  figure  is  determinate  and  constant  under  like  phases  of  existence  for 
each  species,  although  liable  in  the  majority  to  very  great  changes  by  the 
contraction  and  movements  of  the  animalcules,  by  their  contact  with  more 
solid  bodies,  and  by  the  introduction  of  food.  These  changes  are  proportionate 
to  the  elasticity  of  the  integument  and  to  the  contractile  power  of  the  contents ; 
and  hence,  in  several  with  firm  integument,  they  are  veiy  limited,  or  not 
possible. 

The  figui^e  is  also  much  modified  by  the  processes  of  multiplication  and  of 
reproduction.  The  act  of  fission  materially  modifies  it ;  gemmation  does  so 
to  a  less  extent ;  but  the  most  remarkable  change  is  caused  by  the  encysting- 
process,  which  is  generally  a  prelude  to  the  peculiar  set  of  phenomena  attend- 
ing the  reproduction  by  germs  or  embryos,  and,  according  to  Stein's  views, 
would  seem  to  temdnate  in  actual  metamorphosis  or  transformation  of  the 
beings  concerned.  Indeed  the  Ciliata  in  general  appear  to  pass  thi'ough  a 
cycle  of  changes,  each  of  these  entaihng  a  distinct  figure ;  in  other  words, 
in  the  historj^  of  each  ciliated  Infusorium,  there  are  several  phases  of  ex- 
istence, difi'ering  from  one  another  in  form  and  other  particulars.  The  history 
of  an  animalcule,  therefore,  is  comprehended  in  that  of  no  one  form  or  phase, 
but  in  that  of  every  one  it  normally  assumes ;  nevertheless  it  is  necessary  to 
fix  upon  one  phase,  either  as  the  most  important  or  the  most  perfect,  and  to 
characterize  and  name  it,  just  as  is  done  in  the  case  of  insects,  which  are 
described  in  their  most  developed  or  "  imago  "  condition. 

Another  point  to  be  remembered  is,  that  the  figiu'e  of  a  specimen  appears 
diff'erent  in  most  cases,  according  to  the  aspect  in  which  it  is  viewed ;  and, 
again,  there  is  often  much  diversity  in  shape  between  young  beings  and  those 
arrived  at  maturity.  Perty  has  applied  the  term  '  metahoUa  '  to  express  the 
changes  of  figure  animalcules  may  assume.  The  figure  is  extremely  varied 
in  Lacrymaria  by  its  movements,  and  chiefiy  by  the  lengthening  or  shorten- 
ing of  its  elongated  anterior  portion  or  neck.  This  variability  of  form  struck 
Baker  and  other  old  observers  so  forcibly,  that  they  applied  the  term  Proteus 
to  designate  the  animalcule  (XXIV.  274,  275).  Trachelocerca  (XXIV.  317- 
319)  and  PMalina  have  a  similar  power  of  varying  their  outline  ;  and  all  three 
genera  are  further  remarkable  by  the  manner  in  which  their  surface  can  be 
thrown  into  transverse  or  even  intersecting  folds  or  plaits. 

The  influence  of  food  when  swallowed  in  modifying  the  figure,  Ehrenberg 
particularly  illustrated  in  his  Enchehjs  Farcimen  (XXVIII.  group  64).  This 
animalcule  devours  others  nearly  as  large  as  itself,  and,  to  efiect  this,  Avidcly 
dilates  its  mouth,  and  so  becomes  shorter  and  broader  ;   and  as  during  the 


OF  THE  PKOTOZOA. CILIATA.  279 

operation  it  continues  to  swim  about,  its  appearance  with  the  hall- swallowed 
being  is  very  curious.  Again,  when  engulfed  the  anterior  portion  contracts, 
whilst  the  posterior  becomes  dilated,  gi^^ng  the  Enchelys  a  flask-shaped  outline. 

In  descriptions  of  the  Ciliata,  authors  have  used  various  terms,  applied  to 
the  segments  or  members  of  higher  animals,  to  designate  varieties  in  the  form 
and  in  the  mutual  relation  and  position  of  their  parts.  The  application  of 
many  of  these  terms  to  the  Protozoa  is  indeed  very  arbitrary  and  fanciful ; 
and  it  is  only  from  the  absence  of  better  that  we  continue  to  emj)loy  them. 
The  end  of  the  body  which  advances  foremost  in  swimming,  and  at  which  or 
near  to  which  the  mouth  is  ordinarily  placed,  is  called  the  head,  and  often  has 
an  additional  claim  to  the  appellation  by  its  construction  as  a  segment  distin- 
guished by  some  points  of  structure  from  the  rest  of  the  body.  The  opposite 
portion  of  the  animal  constitutes,  when  tapering  or  provided  with  some  sort 
of  process,  the  tail,  but  is  more  generally  spoken  of,  especially  when  not 
distinguishable  as  a  segment,  as  the  posterior  or  caudal  extremity. 

A  '  dorsum '  or  back,  and  a  '  venter '  or  abdominal  surface,  are  usually  de- 
scribed, but  are  not  readily  determinable  in  aU  genera,  as,  for  instance,  in  the 
VorticeUina  and  OpTirydina.  To  distinguish  the  one  surface  from  the  other, 
regard  must  be  had  to  the  position  of  the  mouth  (which  indicates  the  abdo- 
minal surface),  to  that  of  the  locomotive  cilia  and  other  processes,  and  to  the 
mode  of  progression.  But,  after  all,  the  distinction  will  oftentimes  be  arbi- 
traiy,  and  in  consequence  the  description  of  a  right  and  a  left  side  frequently 
so  too.  It  is  a  general  character  of  the  Ciliata,  that  they  are  asymmetrical, 
i.  e.  not  formed  of  two  equal  and  similar  halves.  An  exception  to  this  rule 
exists  in  Coleps  (XXIY.  284)  and  in  the  IchtJujdina  (XXXI.  28-30),  which 
in  Ehrenberg's  system  were  included  with  the  Rotatoria.  Where,  although 
symmetry  is  not  visible,  a  right  and  a  left  side  are  distingiushable,  such  Infu- 
soria are  called  '  bilateral,' — e.  g.  the  O.vytrlcMna  (XXYIII.  10),  Paramecimn 
(XXIX.  25-30),  CMlodon  (XXIX.  48). 

Of  minuter  modifications  in  the  figure  of  Protozoa,  a  large  number  have 
found  names  which  t\tl11  be  best  understood  in  the  special  structiu*al  details  of 
particular  animalcules.  However,  to  mention  some  here  used  by  Ehrenberg, 
we  may  cite  the  frontal  region  or  forehead — the  obtuse  or  truncate  part  of 
the  head  above  the  mouth  ;  the  lips — projections  above  and  below  the  mouth, 
when  this  aperture  is  situated  in  a  fissiu-e  ;  the  tongue  or  palate,  usually  a 
process  in  the  oral  fissure ;  the  rotary  or  ciliary  disk,  seen  as  a  ciliated  pro- 
jectile process  above  the  margin  of  the  anterior  extremity  of  the  VorticeUina 
(XXX.  1,  2,  9,  11,  14).  In  several  genera  the  anterior  portion  of  the  body 
is  much  produced,  and  looks  like  a  long  tubular  neck  or  a  tnmk,  and  hence 
is  called  frequently  by  Ehrenberg  proboscis, — e.  g.  in  the  genera  Lacrymaria 
(XXIV.  274,  275),  Trachelius  (XXIV.  287-289),  Amphileptus,  and  Trache- 
locerea  (XXIV.  317-320).  This  term  proboscis  we  have  already  seen  used 
to  designate  the  long  locomotive  filaments  or  flabella  of  Phytozoa,  totally 
different  processes  from  those  called  by  the  same  name  in  the  CiUata  just 
enumerated.  Its  use  for  one  or  the  other  should  be  set  aside ;  and  although 
at  the  best  it  conveys  a  very  erroneous  impression — for  no  such  thing  as  a 
proboscis  or  trunk,  in  the  proper  meaning  of  the  word,  has  an  existence  in 
any  of  the  Protozoa — its  application  to  these  is  less  objectionable  than  to  the 
Phytozoa.  In  Uroleptus  (XXY.  333)  the  posterior  extremity  is  abniptly 
elongated,  and  forms,  according  to  the  description  of  the  same  distinguished 
naturalist,  a  tail. 

Consistence. — The  Ciliata  are  composed  principally  of  a  very  soft,  almost 
mucilaginous  matter,  which  has  been  well  named  '  sarcode,''  since,  like  the 
flesh  or  muscular  tissue  of  higher  animals,  it  seems  to  present  an  inherent 


280  GENERAL  HISTORY  OF  THE  INFUSORIA. 

contractility  and  elasticity,  and  is  the  active  agent  in  the  movements  of  their 
bodies.  It  is  hyaline,  transparent,  and  colomiess  ;  but  its  refractive  power 
is  not  much  greater  than  water,  which  is  essential  to  the  exhibition  and 
continuance  of  its  properties,  for  when  this  fails  the  homogeneous  mass  of 
sarcode  breaks  up  into  minute  globular  portions,  which  disperse  themselves 
on  every  side.  This  disruptive  process  has  received  the  appropriate  name, 
from  Dujardin,  of  '  diffluence.' 

Ecker  states  this  self-same  sarcode  to  be  the  common  contractile  element 
of  all  the  lowest  forms  of  animal  life — for  instance,  of  the  Polypes.  The  par- 
ticles set  free  by  '  diffluence/  he  also  represents  to  be  contractile,  and  to 
assume  Amceba-like  movements ;  but  this,  according  to  Gohn  and  Stein,  is 
an  error,  inasmuch  as  they  are  simply  elastic.  Cohn  also  adds  that  the 
vaiiable  movements  of  the  sarcode-particles  of  Hydra  are  merely  a  physical 
phenomenon  due  to  endosmosis.  The  process  of  diffluence,  whether  fi'om 
external  injiuious  conditions  or  damage,  or  from  noxious  matters  received 
^vithin,  varies  so  much  in  rapidity,  that  Cohn  (Zeitschr.  1851,  iii.  p.  267)  con- 
eludes  that  it  must  indicate  some  variations  in  its  composition  and  stnicture 
in  different  animalcules.  For  instance,  he  says,  Steator  ccertdeus  bursts ;  and 
its  contents  break  down  by  diffluence  as  rapidly  as  sugar  in  water,  streaming- 
out  from  the  rest  until  the  fimnel-like  pharynx  only  is  left  behind.  On  the 
contrary,  in  other  animalcules,  e.  g.  Paramecium  Aurelia,  the  sarcode  exudes 
through  the  surface  at  all  points,  and  s^dms  away,  lea\ing  a  vacuolated  or 
areolated  interior.  Again,  Loxodes  breaks  up  into  fragments  of  a  considerable 
size,  which  escape  through  lacerations  of  the  sui'fiice. 

Integument.  Markings  on  the  Surface.  Condensed  Integument  or 
LoRiCA.  Appendages  of  Integument.  Cilia.  Spines.  External  Sheaths. 
-— Ehrenberg  described  his  Polygastrica  as  in  all  cases  defended,  and  their 
figure  defined,  by  an  integument  or  skin, — a  statement  as  g-eneraUy  contra- 
dicted by  Dujardin,  though  now  confirmed  (in  the  case  of  all  the  true  Ciliated 
Protozoa)  by  the  researches  of  numerous  later  naturalists.  The  means  resorted 
to  for  its  demonstration,  where  not  otherwise  e\ddent,  consist  in  the  application 
of  chemical  agents — for  example,  of  acetic  acid,  of  tincture  of  iodine,  and  of 
diluted  alcohol,  aU  which  operate  in  a  different  maimer  upon  the  integument 
and  on  the  contents  of  the  body,  most  frequently  causing  a  separation  of  the 
two  by  corrugating  the  latter,  and,  it  may  be,  coloimng  it  at  the  same  time. 

Perty  could  not  convince  himself  of  the  existence  of  an  epidermis,  although 
he  believed  the  external  surface  to  be  modified  so  far  as  to  render  it  more 
resistant,  or  in  fact  to  form  what  Mr.  Carter  calls  a  pelKcle ;  at  the  same  time 
he  attributed  marks  or  lines  visible  on  the  surface  to  fat-  or  other  corpuscles 
subjacent  to  it.  '^The  pellicula,"  Mr.  Carter  says,  '^is  a  structureless  pro- 
duct, which  hardens  after  secretion ;  and  the  inference  is  that  there  is  a  layer 
below  specially  organized  for  its  formation,"  and  that  it  is  not  secreted  by 
the  lamina  known  as  the  "  cortical  layer  "  or  the  ''  diaphane." 

On  the  other  hand  Meyen,  Siebold,  Kolliker,  Erey,  and  Leuckart  conciu- 
in  describing  a  distinct  enveloping  delicate  membrane,  which  Erey  thought 
evidenced  both  by  the  manner  in  which  an  animalcule  ruptures  under  pressure 
and  gives  vent  to  the  soft  contents,  and  by  the  appearance  of  little  shreds  he 
noticed  on  the  torn  edges  of  a  Stentor.  A  more  direct  demonstration  was 
afforded  by  Cohn,  who  resorted  to  chemical  reagents  for  the  purpose. 

This  excellent  observer  experimented  with  several  of  the  larger  Ciliata,  but  for 
illustration  referred  chiefly  to  Lo.vodes  (Paramecium)  Bursar ia.  Stein  argues 
that  the  animalcule  so  described  by  Cohn  was  not  a  Loxodes,  but  a  Paramecium, 
.since  aU  its  cilia  were  of  equal  length,  a  feature  pecidiar  to  this  genus  (Stein, 
op.  cit.  p.  239).     On  adding  a  little  alcohol  to  a  drop  of  water  containing 


OF  THE  PKOTOZOA. CILIATA.  281 

specimens  of  this  animalcule,  death  ensued  ;  but  before  this  happened,  a  deli- 
cate membrane  was  seen  to  elevate  itself  at  parts  of  the  surface,  producing  a 
vesicular  appearance,  and  accompanied  by  a  shrinking  of  the  contained  matters ; 
while  these  changes  proceeded,  several  contiguous  vesicles  would  run  into  one, 
and  thus  strip  more  or  less  completely  the  subjacent  tissue,  until,  by  the  pro- 
longed action  of  the  alcohol,  a  central  shrunken  mass  appeared,  surrounded  by 
a  loose  membrane,  adherent  to  it  only  at  the  spot  where  the  mouth  was  con- 
tinued inwards  as  a  pharynx.  This  membrane,  so  demonstrated,  is  homoge- 
neous and  transparent,  but  not  entirely  structui^eless ;  for  close  observation 
reveals,  over  its  entire  surface,  two  series  of  spirally-disposed,  delicate,  and 
closely-approximated  lines,  which  so  intersect  one  another  as  to  produce  a 
miniature  diamond  pattern  (XXIX.  26).  Further,  the  notched  or  serrated 
appearance  of  the  periphery  (XXIX.  28,  29,  30)  shows  that  these  lines  are 
actually  folds  or  fiuTOWs,  and  that  each  little  chamond  may  be  represented  as 
a  minute  four- sided  pyramid  bearing  a  cihum  at  its  summit. 

By  piu'suing  a  similar  plan  of  investigation,  a  separable  integument  has 
been  demonstrated  in  many  Ciliata.  For  instance,  Stein  described  such  a 
covering  in  the  several  genera  he  subjected  to  observation,  and  proves  its  ex- 
istence also  after  the  process  of  encysting  has  taken  place.  On  adding  dilute 
acetic  acid  to  the  VorticelUna — for  example,  to  specimens  of  Epistylis  or  Oper- 
culcuia — the  contents  shrink  into  a  denser  mass,  and  in  so  doing  detach  them- 
selves from  the  integument,  which  is  then  rendered  evident  as  a  transparent, 
structureless,  homogeneous,  and  smooth  membrane,  having  a  clear,  shai-p  out- 
line. When  tincture  of  iodine  is  applied,  the  integument  remains  uncoloiu-ed, 
whilst  the  contents  acquire  a  golden-yellow  tint.  A  solution  of  sugar,  and 
afterwards  a  drop  of  concentrated  sulphuiic  acid,  being  used,  causes  the  con- 
tents to  swell  up  and  to  assume  a  rose-red  colour,  the  external  wall  continuing 
uncoloiu^ed. 

Eespecting  the  chemical  constitution  of  the  membrane  of  Loxodes,  Cohn 
informs  us  it  is  soluble  neither  in  sulphimc  acid  nor  in  potassa,  whilst  the  con- 
tents are  dissolved  and  dispersed  by  the  latter.  From  this  reaction  he  con- 
cludes that  the  cuticle  is  not  a  proteine  compound,  hke  animal  membrane  in 
general,  but  the  substance  called  chitine,  and  therefore  in  this  respect  similar 
to  the  cuticle  orplants.  In  Parmnecmm,  he  adds,  an  integument  having  the 
same  sort  of  markings  and  a  similar  chemical  reaction  exists,  and  that,  with- 
out doubt,  aU  the  species  described  by  Dujardin  as  having  a  reticulated 
envelope,  in  his  families  ^  Bui'sariens '  and  '  Parameciens,'  have  a  hke  structure. 
Moreover,  this  sldn  has  its  special  characters  in  different  genera,  as  is  illus- 
trated in  the  above  accoimt  of  Paramecium  Bursaria,  and  may  be  exemplified 
in  other  cases.  Thus  in  Coleps  and  Stentor  polymorphus,  the  cuticle  is  so 
intersected  by  lines  as  to  leave  intermediate  four-sided  prisms,  each  of  which 
bears  a  cihum  at  its  apex,  whilst  at  the  intersection  of  the  lines,  single  long 
hairs  are  also  seen,  similar,  says  Lachmann  {A.  N.  H.  1857,  xix.  p.  1 2b,  in  foot- 
note), to  the  hairs  of  many  TnrheUaria.  Again,  Ophrydium  versatile  has  its 
integument  thrown  into  fine,  closely-aggregated,  annular  folds,  and  into  three 
longitudinal  rugae  on  one  side  (XXX.  5),  which  disappear  when  the  animal 
shortens  itself  by  contraction  (XXX.  6).  Spirochona  (XXX.  17),  says  Stein 
(p.  208),  has  a  hyaline,  firm,  inflexible  parchment-Hke  sldn,  with  a  distinct 
double  outline,  but  mthout  any  inherent  contractility.  It  is  most  like  the 
integument  of  Euplotes,  but  differs  apparently  in  not  being  capable  of  falhng 
into  folds  around  the  body.  It  resists  the  action  of  acetic  acid,  which  dis- 
solves out  the  whole  of  the  Hving  contents,  and  leaves  it  in  an  isolated  state. 

Whilst  representing  all  animalcules  to  be  covered  with  an  integument, 
Ehrenberg  distinguished  those  enclosed  by  a  firm,  more  or  less  unyielding, 


282  GENERAL  HISTORY  OF  THE  INFUSORIA. 

envelope  or  sheath,  as  '  loricated,'  in  opposition  to  the  rest,  which  he  called 
*  illoricated.'  These  terms  he  has,  however,  employed  in  so  loose  a  manner, 
that  they  really  possess  no  definite  and  constant  meaning.  For  example,  the 
sheaths  of  encased  animalcules  represented  by  the  Opliy^ydina  are  designated 
loric£e,  the  enclosed  animal,  although  possessing  a  distinct  integument,  being 
considered  naked, — while,  again,  the  indm^ated  closely-fitting  integiiment  of 
Eivplotes  and  Coleps  is  equally  styled  a  lorica,  although  so  different  in  cha- 
racter and  relations.  The  term  lorica  could  only,  indeed,  be  legitimately 
employed  either  to  designate  the  sheaths  of  such  animalcules  as  the  Opliry- 
clina,  or  the  indiu-ated  integument  of  others,  as  Coleps, — to  one  or  the  other, 
but  not  to  both  ;  to  the  former  it  is  unnecessaiy,  to  the  latter  it  is  admissible. 

The  integument  of  the  Ciliata  has  generally  been  regarded  to  be  in  itself 
contractile  ;  but  it  seems  that  this  is  an  error,  and  that,  in  fact,  it  is  simply 
elastic.  As  such,  its  action  must  be  counter  to  that  of  the  subjacent  con- 
tractile layer,  and  be  therefore  the  chief  agent  in  restoring  the  figure  when 
the  contractile  force  is  relaxed  ;  at  the  same  time  its  elasticity  will  allow  of 
considerable  alterations  in  form,  from  contact  and  pressure  of  external  more 
rigid  objects.  To  this  an  exception  occiu^s  in  the  case  of  those  Ciliated  Pro- 
tozoa in  which  the  integument  is  much  hardened,  and  forms  a  lorica  or  shield. 
This  induration  may  be  more  or  less  extensive,  so  as  either  to  cover  the  dorsum 
Avith  a  shield-like  plate  (scutellum),  as  in  Chlamidodon,  or  to  entirely  sur- 
round the  animalcule,  as  in  Coleps,  when  it  constitutes  an  "  urceolus,"  open 
at  the  ends. 

The  external  envelope,  when  thus  hardened,  has  developed  from  it  various 
processes,  of  a  more  or  less  rigid  character,  which  look  hke  spines  (setae) 
(XXiy.  284,  285),  or  hooks  (uncini)  (XXV.  344,  347),  or  are  elongated  as 
styles  (XXXYIII.  10 ;  XXV.  350,  351),  all  which  are  oftentimes  made  sub- 
servient to  the  act  of  locomotion,  and  less  frequently  to  that  of  prehension  also. 
It  must,  however,  be  admitted  that  such  processes  are  not  confined  to  genera 
in  which  the  integument  is  veiy  appreciably  indurated,  but  occur  where  it  is 
of  softer  consistency — for  instance,  in  Stylonychia  (XXV.  343,  344). 

The  integument  is  combustible  and  also  diffluent,  even  when  indurated,  just 
as  are  the  softer  contents,  although  more  slowly. 

External  Sheaths  or  Cases. — Before  quitting  the  accounf  of  the  common 
integument  or  cuticle  immediately  investing  the  body  of  the  Ciliated  Protozoa, 
a  description  of  an  homologous  membrane,  in  fact,  of  a  prolongation,  dedu- 
plication,  or  process  of  it,  in  the  form  of  an  external  sheath  or  case  about 
certain  fixed  species,  becomes  necessary. 

The  species  so  encased  are  either  sessile  or  have  only  a  short  stalk  attach- 
ing them  to  the  bottom  of  the  case ;  thus  Vaginicola  (XXVII.  10,  11)  is 
stalkless  or  nearly  so,  whilst  Tintinnus  has  a  more  appreciable  pedicle :  on 
the  other  hand  the  case  itself  may  be  stalked,  as  in  Cothurnia  (XXX.  12-16) ; 
where  this  happens,  the  stem  does  not  equal  the  length  of  the  sheath,  but  is 
short,  solid,  and  thick,  expanding  upwards  to  its  attachment  with  the  base 
of  the  latter,  and  frequently  thrown  into  transverse  folds  and  curved  (XXX. 
12, 15).  It  is  homologous  with  the  rigid  stem  of  Epistylis,  which  it  resem- 
bles also  in  chemical  characters. 

A  very  remarkable  exception  to  the  general  rule  of  the  attachment  of 
tunicated  VorticelUna  to  the  bottom  of  their  case,  occurs  in  the  new  genus 
Lacjenophrys,  in  which  the  animalcule  is  suspended  from  the  narrow  aperture 
of  the  sheath,  so  as  to  leave  a  more  or  less  considerable  space  aroimd  it 
(XXX.  29-34).  The  margin  of  the  head  of  the  animal,  i.  e.  the  peristom,  is 
beneath  the  opening  of  the  sheath,  which  has  the  further  pecuHarity  of  being 
very  narrow  and  two-lipped  (XXX.  29,  32,  34).     In  one  species  {L,  nassa)  a 


OF  THE  PROTOZOA. CILIATA.  283 

cylindrical  short  tube,  with  a  serrate  edge  and  longitudinally  striated,  is  re- 
presented by  Stein  to  project  from  the  opening  of  the  sheath.  It  is,  he  adds, 
separable  above  into  two  lips,  which  close  when  the  animal  retracts  itself. 

It  is  not  very  unusual  to  meet  with  sheaths  occupied  by  two  animalcules, 
— a  cii'cumstance  due  to  the  act  of  self- division  (XXVII.  10  ;  XXVIII.  19). 
In  a  few  instances  also,  one,  two,  or  more  small  young  individuals  lie  free 
within  the  sheath  of  the  parent,  e.  g.  Lagenophrys  (XXX.  29,  34).  The 
sheath  is  always  a  product  secreted  from  the  animalcule,  and  first  makes  its 
appearance  around  its  base  as  a  soft,  homogeneous,  colourless,  jelly-like  matter. 
Diuing  the  process  of  its  formation,  the  animal  preserves  a  contracted  state, 
which  diminishes,  however,  as  the  excreted  layer  advances,  and  ceases  on  its 
completion ;  and  since  each  genus  has  a  characteristic  outline,  as  well  in  the 
contracted  as  in  the  expanded  condition,  the  sheath  acquires  also  its  special 
character  only.  More  or  less  of  the  posterior  extremity  is  concerned  in  ex- 
creting the  formative  matter ;  but  this  having  adhered  to  the  anterior  part 
whilst  in  a  contracted  state,  becomes  di'awn  forward  by  the  progressive 
elongation  of  the  entire  body,  until  at  length,  on  full  expansion  taking 
place,  the  connexion  is  broken  and  the  sheath  acquires  a  free  edge.  So  soon 
as  excreted,  the  gelatinous  layer  proceeds  to  solidify,  and  simultaneously  to 
contract  itself  in  thickness,  so  as  to  form  a  membrane,  which,  on  its  subse- 
quent detachment  from  the  fore  part  of  the  animal,  forms  a  loosely-investing 
case  aroimd  it.  This  description  of  the  construction  of  the  sheath  applies  to 
all  those  genera  where  the  animal  is  fixed  at  the  bottom  ;  but  in  the  instance 
of  Lagenophrys,  where  it  is  suspended  from  the  constricted  orifice  of  the  case 
by  its  peristom,  some  other  plan  of  formation  must  be  presumed,  concerning 
which,  however,  we  have  as  yet,  unfortunately,  no  direct  observation  to  teach 
us.  In  several  species,  as  Goihurnia  imberbis,  the  sheath  not  merely  acquires 
a  parchment-Kke  firmness,  but  also  a  decided  colour — mostly  yellow  at  first, 
afterwards  a  rusty  red. 

Dr.  StrethiU  Wright,  of  Edinburgh,  has  kindly  sent  us  some  notes  on  the 
intimate  structure  of  the  sheath  of  Lagotia ;  and  doubtless  they  hold  good  to 
a  greater  or  less  extent,  so  far  as  they  represent  general  facts,  in  the  case  of 
sheaths  of  other  Oplirydina.  He  wiites — "  The  tube  consists  of  yellowish 
chitine,  lined  with  a  layer  of  dark-green  sarcode  of  varying  thickness  (which, 
I  believe,  secretes  the  chitine),  and  covered  externally  by  a  much  thinner 
layer  of  matter,  which  appears  to  be  equivalent  to  the  ^  coUetoderm '  of  the 
Hydroidce:'  This  structure  is  illustrated  by  figs.  12  and  13,  PI.  XXXI. 
The  following  accoimt  applies  specially  to  the  sheath  of  Lagotia  (XXXI.  7,  8, 
12, 13),  which  presents  a  series  of  rings,  apparently  spiral,  but,  in  our  opinion, 
not  so.  '^  The  Hnes,"  says  Dr.  Wright,  "  are  seen  to  consist  of  the  remains  of 
the  tmmpet-shaped  mouth,  which  is  partially  absorbed  as  the  tube  increases 
its  length,  but  stiU  remains  as  a  slightly-overlapping  ridge  over  the  new  part 
of  the  tube  growing  within  it.  The  groove  thus  formed  is  filled  up  with  the 
*  coUetoderm.'  The  spiral  character  seems  to  be  in  some  way  connected  with 
this  mode  of  growth ;  but  I  have  not  satisfied  myself  in  what  way."  In  a 
subsequent  letter  he  writes — ^'  The  chitinous  matter  of  each  successive  ring 
is  not  continuous  with  that  of  the  lings  above  and  below  it ;  it  is  only  at- 
tached to  it  by  the  inner  lining  of  sarcode  and  by  its  outer  covering  (XXXI. 
12,  13).  We  have  by  this  condition  a  provision  for  the  growth  of  the  tube, 
both  in  width,  length,  and  thickness,  similar  to  that  which  occurs  in  the 
shell  of  Echinus,  Growth  in  length  may  be  eff'ected  by  deposition  of  chitine 
on  the  upper  and  lower  edge  of  each  ring,  growth  in  breadth  by  the  gradual 
unrolling  of  the  spiral,  while  a  continuous  deposition  of  hard  matter  from 
the  inner  lining  of  sarcode  thickens  and  strengthens  the  whole  tube." 


284  GENERAL  HISTORY  OF  THE  INFUSORIA. 

In  spealdng  of  the  attachmeut  of  the  sheath,  we  have  mentioned  only  that 
by  the  base,  with  or  without  a  stalk.  But  there  are  a  few  fonns  which  affix 
themselves  to  foreign  bodies  by  one  side  of  their  sheath,  e.  g.  Vaginicola 
decumhens  (Ehr.)  and  the  genus  Lagenophrys.  In  such  cases  the  attached 
side  is  flattened,  so  as  to  increase  the  sui^face  in  contact. 

But,  apart  from  the  mode  of  attachment,  the  sheaths  of  different  genera 
vary  in  figm^e  ;  and  as  to  size,  there  is  no  constant  relation  between  that  of  the 
ease  and  that  of  the  enclosed  being.  The  figure  of  the  sheath,  even  in  one 
and  the  same  species,  is  subject  to  modification  fi'om  age  and  from  suri'ounding 
circumstances.  Thus,  in  Vaginicola  crystallina  it  is  usually  cylindrical  and 
truncate  (XXYII.  11),  but  at  times  it  may  be  bellied  posteriorly  (XXYII.  10), 
or,  otherwise,  have  its  anterior  border  expanded  and  curved  outwards,  or  be 
narrowed  in  front,  or  comj)ressed  in  one  direction.  Nevertheless  there  is 
usually  a  general  resemblance  in  figui-e  among  individuals  of  the  same  species  or 
genus,  sufficient  to  furnish  descriptive  characters.  For  example,  Cothurnia 
imberbis  has  commonly  a  cylindiical  sheath,  bellied  posteriorly  and  shghtly 
contracted  anteiioiiy  (XXX.  15),  whilst  C.  Sieboldii  is  campanulate,  and  has 
its  anterior  half  compressed  in  one  direction,  and  its  angles  in  front  prolonged 
and  tapering  (XXX.  13,  14).  In  the  genus  Lagenophrys,  when  adherent  by 
its  flattened  side,  the  sheath  appears  ovoid  or  shaped  like  a  bellied  oil -jar,  ^ith 
a  contracted  truncate  mouth  (XXX.  29,  30).  A  peculiar  form  of  sheath  is 
presented  to  us  in  the  genus  Lagotia  (XXYIII.  21,  23),  which  may  be  de- 
scribed as  retort- shaped,  the  relative  diameter  and  length  of  the  body  and 
neck  differing  in  different  specimens  or  species.  In  one  species,  at  least,  the 
neck  has  the  further  peculiarity  of  being  throT^^l  into  spiral  or,  otherwise, 
annular  folds  or  rings  (XXXI.  7,  8),  the  presiuned  form  and  origin  of  which 
have  just  been  described. 

We  are  fiu'ther  indebted  to  the  discoverer  of  Lagotia  for  the  recognition  of 
a  remarkable  valvular  structure  within  the  tubular  sheath  of  a  species  of  Va- 
ginicola, which  he  in  consequence  names  Vag.  valvata  (XXYIII.  18,  19). 
Dr.  Wright  states  (Edin.  New  Phil.  Joiirn.  April,  1858) — "  On  examining 
the  valve  in  situ,  I  found  it  to  consist  of  a  rigid  plate  imbedded  in  a  thick 
layer  of  transparent  sarcode  (XXYIII.  18  b),  which  latter  was  continuous  at 
the  lower  end  of  the  valve  with  a  thin  layer  of  the  same  substance,  lining 
the  whole  of  the  interior,  and  coating  the  upper  part  of  the  exterior  of  the 
tube.  The  valve  was  closed  by  a  contractile  process  passing  from  its  under- 
surface  to  the  wall  of  the  tube ....  I  am  disposed  to  consider  the  whole  ap- 
paratus to  consist  of  an  oval  plate  of  soft  sarcode,  supported  by  an  included 
bar  or  narrow  plate  of  horn  or  chitine ....  In  some  specimens  the  tube  was 
marked  w^ith  close  transverse  or  cii'cular  striae." 

In  Stentor  Mi'dleri  (XXYIII.  16,  17),  we  have  the  curious  instance  of  an 
animal  living  indifferentl}^  with  or  without  a  sheath,  and  enjoying  fi^eedom  of 
movement.  Amidst  numerous  specimens  of  this  species,  not  a  few  (says  Cohn) 
may  be  seen  swimming  freely  about,  or,  otherwise,  attached,  enclosed  within  a 
roomy  ovate  sheath,  composed  of  a  soft  gelatinous  substance,  and  open  at  one  end 
(XXYIII.  17).  The  animalcule  is  fixed  by  its  posterior  extremity  (apparently 
converted  for  the  time  mto  a  suctorial  disk)  to  the  closed  end  of  the  sheath  ;  but 
it  is  still  able  to  evert  its  spiral  ciliary  wreath,  and  to  extend  itself  beyond  the 
open  mouth,  or  to  retract  itself  in  a  contracted  condition  witliin  its  interior. 
Ehrenberg  remarked  the  exudation  of  a  mucous  sheath  around  this  animal- 
cule when  kept  confined  for  some  time  for  observation  within  small  glass 
tubes,  but  mistook  it  for  a  sort  of  morbid  act  preparatory  to  death.  Cohn,  on 
the  contrary,  has  shown  {Zeitschr.  1853,  iv.  p.  263)  that  it  is  in  no  way  con- 
nected with  disease  or  "v^dth  approaching  death,  but  happens  with  individuals 


OF  THE  PROTOZOA. CILIATA. 


285 


in  fiill  ^'ital  activity  and  surroimded  by  favourable  external  conditions,  and 
adds  that  gemmation  frequently  proceeds  in  these  encased  beings,  and  that, 
■when  from  evaporation  of  the  surrounding  fluid  or  other  prejudicial  cause  the 
animals  are  threatened  with  injury,  they  quit  their  sheaths  and  swim  away, 
the  pre^'iously  suctorial  extremity  resohdng  itself  into  a  pencil  of  bristles. 
The  result  of  these  observations  of  Cohn  is  to  disassociate  this  phenomenon  of 
sheath-formation  in  Stentor  from  that  of  the  encysting  process,  to  which 
Ehrenberg's  account  of  it  would  have  led  it  to  be  referred. 

Dr.  Strethill  Wright  coincides  "\^'ith  Cohn  in  denying  the  relation  between 
the  presence  of  the  sheath  of  Stentor  Mulleri  and  the  diseased  or  dying  state 
of  the  animalcule.  Indeed  he  speaks  of  the  presence  of  a  gelatinous  case 
as  the  rule,  and  adds  that  ''  as  the  zooids  (animalcules)  di\dde  they  form  a 
gelatinous  mass,  which  is  attached  to  weeds  and  often  to  the  siuface  of  the 
water,  from  which  I  have  seen  some  10  or  15  combined  Stentors  hanging 
with  their  heads  downwards." 

Cilia  ais^d  Ciliaey  Action. — The  most  common,  and  at  the  same  time  the 
characteristic  external  appendages  of  the  Ciliated  Protozoa  are  the  cilia,  Avhich 
constitute  their  most  active  and  powerful  locomotive  organs.  Cilia  are, 
moreover,  not  wanting  internally,  but  are  there  comparatively  few,  since 
they  are  appendages  only  of  free  surfaces.  They  are  met  with  lining  the 
oesophagus,  where  they,  no  doubt,  seiwe  to  facilitate  the  ingestion  of  food  and 
of  the  water  taken  in  for  the  purposes  of  aeration. 

The  nature  and  cause  of  ciliary  movement  have  been  much  debated.  To 
account  for  the  energetic  and  peculiar  movements  of  cilia,  Ehrenberg  imagined 
the  existence  of  a  muscular  aj)paratus  at  their  globular  roots,  consisting  of  four 
muscles,  each  pulling  in  an  opposite  dii'ection,  but,  by  acting  in  succession, 
causing  the  apparent  rotation  of  the  axis  around  the  fixed  base.  This  bold 
idea  has  met  with  no  favour  among  physiologists,  who  condemn  it  as  purely 
imaginary  and  as  opposed  to  the  simplicity  of  natiu-e,  to  all  analogy,  and  to 
aU  the  admitted  facts  and  principles  of  liistology.  Most  inquirers  despair  of 
attaining  a  satisfactory  explanation,  of  ciliary  action,  and  treat  it  as  an  ulti- 
mate fact.  However,  Cohn,  looking  to  the  peculiar  structure  of  the  integu- 
ment of  Paramecium  {Loxodes)  Bursaria  (XXIX.  26),  fancied  that  ciliary 
motion  admitted  of  explanation,  since,  on  the  supposition  of  an  inherent 
contractility  in  that  membrane,  each  Kttle  pyramid  might  be  imagined  to 
contract  its  sides  in  turn,  and  make  the  cilium  surrounding  it  revolve  in  the 
figure  of  an  inverted  cone.  But  granting  the  possibility  of  this  explanation 
in  the  case  of  the  animalcule  cited,  it  could  in  no  wise  be  applied  generally 
to  cihary  motion ;  for  a  similar  structiu-e  is  found  in  comparatively  few  other 
examples,  and  the  innate  contractility  of  the  supporting  membrane,  assumed 
in  the  instance  in  question,  has  certainly  no  existence  in  many  ciliated  sur- 
faces, and  involves  nearly  an  equal  stretch  of  imagination  to  conceive  as 
Ehrenberg's  muscles. 

Returning  from  this  digression  on  the  nature  and  cause  of  ciliary  action, 
let  us  briefly  review  the  mode  of  distribution  of  cilia  in  the  Protozoa.  In. 
many  genera  they  are  chstributed  universally  over  the  surface  (XXIX.  20, 
28,  48 ;  XXYIII.  1,  8,  31),  not  at  random,  however,  but  in  definite  parallel 
lines,  more  or  less  approximated,  usually  traversing  the  length  of  the  body. 
A  distribution  in  parallel  lines  is  also  not  unfrequently  obsei-ved  across 
or  around  the  body.  Even  where  generally  difi'used  over  the  body,  they  are 
commonly  more  developed  at  certain  parts,  as  about  the  mouth,  the  head,  and 
tail,  as  well  as  on  any  processes  or  in  any  depressions  of  the  body,  e.  g.  in 
Chihdon  (XXIX.  48),  Bursaria,  Leucophrys,  Stentor,  &c.  Stein  represents 
it  as  a  generic  character,  that  in  Paramecium  (XXIX.  28)  all  the  cilia  are 


286  GENERAL  HISTORY  OF  THE  INFUSORIA. 

of  uniform  length.  In  Coleps  (XXIV.  284),  the  lorica  is  divided  into  a  mul- 
titude of  minute  facettes  bj  intercurrent  lines  or  sulci,  and  the  cilia  are  placed 
at  the  points  of  their  intersection.  In  Colpoda  Cucidlulus  (XXIX.  35,  36,  37), 
the  cilia  are  much  longer  at  the  anterior  prolonged  extremit}^,  the  lip,  just 
as  in  Chilodon  ;  but  there  is  besides,  in  the  deep  sulcus  where  the  mouth  is 
found,  a  dense  pencil  of  long  and  strong  cilia  (XXIX.  37),  which  Ehrenberg 
mistook  for  a  solid  process  of  the  body,  and  called  the  "  tongue."  From  this 
fasciculus  or  bundle,  a  row  of  long  cilia  is,  moreover,  seen  to  extend  backwards 
to  the  posterior  extremity  (XXIX.  37). 

Other  groups  of  Ciliated  Protozoa  have  the  cilia  confined,  more  or  less  strictly, 
to  one  part  or  organ  of  the  body, — a  circumstance  exemplified  in  the  Vortl- 
cellina  and  Ophrydina  (XXX.  1,  2,  5,  9  ;  XXIX.  1,  3,  4,  5).  This  Hmita- 
tion,  as  contrasted  with  the  general  diffasion  of  cilia,  imphes  an  advance  in 
the  scheme  of  organization,  and  is  attended  by  the  constniction  of  a  special 
apparatus  about  the  head  of  the  animalcules.  Thus,  in  the  families  named, 
the  rule  is  that  the  anterior  extremity  is  bounded  by  an  evident,  mostly  thick- 
ened margin,  either  curved  or  straight — the  "peristom  " — crowned  with  vibra- 
tile  cilia  and  complicated  by  an  internal,  usually  extensile,  ciliated  disk  or 
rotary  organ  (XXX.  1,  2,  9  a,  29  «),  the  whole  apparatus  recalling  the  stnic- 
ture  of  the  rotary  organ  of  the  Rotatoria.  The  cilia  appertaining  to  the  pe- 
ristom  and  disk  are  highly  developed  and  strong,  although,  instead  of  ser\dng 
for  locomotion,  they  only  subserve  the  processes  of  nutrition  and  aeration  or 
respiration,  by  reason  of  the  fixed  condition  of  the  animalcules  possessing  them. 

Another  peculiarity  of  the  ciliar}-  apparatus  of  the  Vorticellina  and  Opliry- 
dina  is  that  it  is  retractile  (XXX.  6  a),  or  can  be  involuted  and  withdi-awn 
into  the  interior  of  the  animal  (XXX.  13),  and  the  peristom  closed  completely, 
and  contracted  sometimes  so  far  as  to  di-aw  in  a  part  of  the  wall  around  it, 
and  not  leave  a  single  ciKum  visible  externally  (XXX.  11b,  31,  33).  When 
thus  retracted,  the  ciHated  organ  appears  like  an  internal,  irregular-sigmoid, 
contracted  cavity  or  fissure,  with  the  cilia  closely  packed  together  and  scarcely 
distinguishable  (XXVII.  5  a,  b  ;  XXX.  11  b).  The  retraction  of  the  ciliary 
wreaths,  which  takes  place  very  rapidly,  is  caused  by  the  presence  of  sur- 
rounding objects  in  the  immediate  vicinity  of  the  animal,  by  their  contact 
with  it,  by  any  shocks  it  may  feel,  and  by  the  presence  of  noxious  matters  in 
the  water.  On  the  removal  of  such  and  similar  causes  of  annoyance,  the  ex- 
tension of  the  delicate  apparatus  follows ;  this  act,  however,  is  less  rapid  than 
that  of  retraction,  and  may  be  arrested  at  any  point. 

A  more  permanent  withdrawal  of  the  rotary  apparatus,  in  the  families 
named,  occurs  when  the  process  of  self- division  is  about  to  proceed  (XXVII.  3  ; 
XXVIII.  18),  and  also  when  the  animalcule  prepares  to  enter  into  the  en- 
cysted condition  (XXVII.  5,  7). 

The  disappearance  of  ciHa  is  witnessed  not  only  in  Vorticellina  and  Ophry- 
dina  when  the  process  of  encysting  takes  place,  but  is  a  general  phenomenon 
among  ciliated  organisms  under  the  same  circumstances  ;  yet  it  would  appear 
that  in  some  cases,  even  when  an  animalcule  has  surrounded  itself  with  a 
cyst,  its  cilia  are  not  actually  lost,  but  only  withdrawn  from  view, — a  fact 
adverted  to  by  Stein  in  his  account  of  Chilodon  Cucidlulus,  which  at  times, 
after  encysting  itself  and  developing  one  or  more  Hving  germs  within  the 
cyst,  has  been  seen  to  renew  its  original  appearance,  to  regain  its  cilia  upon 
its  surface,  and,  after  rotating  for  a  while  within  the  sac,  to  burst  at  length 
through  it  and  escape  (XXIX.  55,  58).  Moreover  many  observers  have 
asserted  the  fact  that  an  animalcule  may,  soon  after  encysting  itself,  be  set 
free  by  rupturing  the  cyst  by  pressure,  and  then  reassume  its  previous  ciliated 
and  active  condition.     Nevertheless  the  act  of  encvsting,  when  advanced  to 


OF  THE  PROTOZOA. CILIATA.  287 

a  certain  point,  or  when  the  reproductive  process  consequent  upon  it  differs 
from  that  seen  in  Chilodon,  appears  to  involve  the  final  disappearance  both 
of  generally  diffused  cilia  and  of  specially  organized  ciliary  wreaths. 

The  an-est  of  the  motion,  and  the  ultimate  disappearance  of  cilia,  are  phe- 
nomena attendant  also  on  the  death,  or  on  the  approaching  diffluence,  of  ani- 
malcules— when  the  surrounding  w^ater  dries  up,  or  when  their  vitality  is 
injiu'ed  by  chemical  agents  or  by  physical  forces,  such  as  electricity  and  heat. 
Stein,  however,  states  that,  although  the  animalcule,  e.  g.  a  Paramecium,  is 
killed  by  the  addition  of  very  dilute  acetic  acid,  yet  its  cilia  continue  visible 
and  of  their  normal  length.  Cohn  behoved  the  cilia  to  be  very  much  longer 
than  Ehrenberg  represented ;  but,  as  Stein  affirms,  this  notion  originated  from 
an  unnatural  appearance  consequent  on  the  dying  state  of  the  animalcule,  from 
evaporation  of  the  surrounding  water ;  and  he  adds  that  a  similar  elongation 
of  cilia  appears  immediately  at  the  point  where  strong  acetic  acid  comes  into 
contact  with  the  suiface.  But  this  explanation  has  since  been  set  aside  by 
Prof.  Allman's  discovery  of  the  existence  of  trichocysts,  or  thread-cells, 
within  the  subtegumentary  layer  of  the  body  (XXXI.  1-4),  to  which  he  at- 
tributes the  phenomena  observed  and  discussed  by  Cohn  and  Stein. 

An  instance  of  a  temporary  formation  of  cilia  is  seen  in  the  VorticeUina 
and  OpTirydina  when  the  offspiing,  formed  by  fission  or  by  gemmation,  is  pre- 
pared to  detach  itself  from  the  parent  being.  Under  such  circumstances,  and 
prior  to  the  development  of  the  interior  retractile  ciliary  organ,  a  wreath  of 
ciha  makes  its  appearance  (XXVII.  4, 11)  near  the  posterior  extremity — but 
which,  indeed,  for  the  time,  advances  first  in  swimming,  and  continues  to  do 
so  until  the  animalcule  has  attached  itself  and  proceeds  to  unfold  the  ciliated 
apparatus  at  its  head. 

In  the  above  account,  reference  has  been  chiefly  made  to  vibratile  cilia,  but, 
as  before  noticed,  there  are  tegumentary  processes  of  larger  size,  coarser  and 
stiffer,  and  withal  not  vibratile,  although  moveable.  Such  serve  frequently 
as  special  organs  of  locomotion,  or  of  prehension,  or  of  both,  and  may  also  be 
occasionally  considered  weapons  of  offence  and  defence.  Accordiag  to  their 
form  they  are  named  set<x,  or  bristles ;  uncini,  or  hooks ;  cirrif  styles  and 
filaments. 

Some  of  these  terms  are  both  loosely  defined  and  used.  Thus  the  bristles 
so  called  of  one  author,  are  spoken  of  by  another  as  cirri,  or  styles  or  fila- 
ments,— the  structures  thus  variously  called  being  long  bristles,  mostly  taper- 
ing, and  either  straight  or  but  slightly  ciuwed.  The  term  "  czn-i "  (in  EngEsh, 
tendrils)  should  be  disused,  both  as  being  unnecessary  and  also  as  conveying  an 
erroneous  conception  ;  for  no  organs  like  tendrils  exist  among  Protozoa.  Un- 
cini (hooks)  are  very  thick  at  the  base,  strong,  curved,  and  comparatively  short 
processes  (XXIX.  15,  17) ;  styles  are  stout  setiform  bristles,  articulated  at 
their  base  to  the  cuticle,  and  of  considerable  length  (XXYIII.  10 ;  XXV. 
350,  351).  These  last-named  processes,  Lachmann  tells  us,  are  sometimes 
spHt  up  at  the  apex  into  two,  or  even  as  many  eight,  parts,  as  happens  in 
various  Euplotes  (for  instance,  E.  Patella,  in  which  species,  moreover,  one 
style  bears  a  number  of  small  lateral  setiform  branches).  The  divided  styles 
occur  at  the  posterior  extremity,  and  are  trailed  along  in  the  movements  of 
the  animals,  and  only  occasionally  employed  in  pushing  them  forwards,  whilst 
the  uncini  in  advance  serve  for  actual  creeping  and  cHmbing.  As  examples 
of  these  tegumentary  appendages,  may  be  adduced  the  setae  of  Urostyla  and 
Kerona ;  jthe  uncini,  setae,  and  styles  of  OccytHchina  (XXVIII.  10),  Euplotes 
(XXV.  350-353),  and  ofPloesconia.  Intermediate  grades,  between  the  highly- 
developed  setose  processes  cited  and  ordinary  vibratile  ciha,  may  be  seen  in 
the  larger  and  more  rigid  ciliary  structures  alluded  to  above  as  often  found 


288  GENERAL  HISTORY  OF  THE  INFUSORIA. 

along  the  margin  of  animalcules,  on  eminences  and  in  depressions  and  other 
particular  parts  ;  such  Lachmann  would  name  "  ciliary  bristlesJ'  In  Tricho- 
dina  Pediculus  (XXIX.  17),  Stein  describes  a  ciixle  of  uncini  supported  on  a 
cartilaginous  or  corneous  ring,  and  extenial  to  this  a  yellowish  membrane  of 
comeoiLS  consistence  and  extraordinary  flexibility,  with  closely-placed  striae 
across  it.  On  a  lateral  "vdew  of  the  animalcule,  this  membrane  is  seen  to  rise 
round  the  circlet  of  uncini  like  a  raised  rim  (XXIX.  17/). 

LOCOMOTIYE  AND  FlXED    FoEMS  OF   THE  CiLIATA.       VARIETIES  OF  LoCOilOTION. 

Transitory  Power  of  Locomotion  among  the  Attached  Genera.  Pedicle 
Single  and  Branched.  Varied  Outline  of  Ramified  Stems.  Structure  of 
Stem.  Contractile  Stems.  Rigid  Stems. — The  Ciliata,  with  respect  to  the 
function  of  locomotion,  present  themselves  under  two  groups, — one  compre- 
hending those  genera  which  at  all  periods  of  their  existence  can  move  from 
place  to  place  at  will,  the  other  embracing  aU  those  which  under  ordinary 
conditions  are  attached  by  means  of  a  stem  or  pedicle,  of  greater  or  less  length. 

The  foimer — the  locomotive  group — includes  the  larger  number  of  genera, 
in  aU.  of  which  the  cilia  are  more  or  less  generally  dLstributed  over  the  entii-e 
body.  Theii'  swimming  movements  are  especially  due  to  the  cilia,  but  may  be 
aided  by  other  tegumentaiy  processes,  by  setae,  styles,  or  uncini,  and  lq  several 
instances  by  the  general  figure  of  the  body.  It  is  rare  that  swimming  is  a 
simple  onward  movement ;  on  the  contrary,  it  is  usually  attended  with  a 
rotarv  motion  about  the  long — seldom  the  short — axis  of  the  body  ;  and  when 
the  animalcule  is  considerably  elongated,  it  becomes  undulating,  as  m  an  eel. 
In  the  case  of  Spirostomiim  (XXIV.  297,  298),  the  elongated  ribbon-like 
figiu'e  is  particularly  favourable  to  rapid  writhing  motion.  In  short,  as  before 
intimated,  the  developement  of  the  body  to  a  greater  extent  in  one  or  more 
parts,  so  as  to  form  processes,  or  the  constriction  of  a  portion,  reducing  it 
to  the  dimensions  of  a  member,  or  the  lengthening  of  the  entire  animal  into 
a  band-like  or  ligulate  figure  is  made  subservient  to  the  piu'pose  of  locomo- 
tion, and  imparts  to  it  a  more  or  less  special  character.  Moreover,  the  loco- 
motive Ciliata  have  the  power  of  altering  the  direction  of  their  movements, 
and  wiU  often  retrace  their  course,  and  this  frequently  without  tiu-ning  them- 
selves round  in  order  to  advance  the  same  extremity  foremost. 

The  simple  movement  of  swimming  is  common  to  all  the  Ciliata ;  but  in 
the  case  of  those  furnished  with  setae  and  uncini,  a  creeping  or  crawling 
motion  is  superadded,  as,  for  example,  in  ^iylonychki  (XXVIII.  10),  Himan- 
tophorus,  Euphtes,  and  Kerona  (XXV.  '622,  328,  347,  353).  In  several 
of  these  examples  we  find  one  side  of  the  body  covered  T\ath  a  more  resistant 
integument  or  shield,  whilst  the  locomotive  uncini  or  setae  are  disposed 
along  the  other,  just  as  in  the  case  of  a  myriapodous  insect,  and  supply  a 
locomotive  apparatus  whereby  the  animalcules  can  nm,  with  much  activity, 
over  the  surface  of  an  Alga  or  other  solid  body,  or  climb  it  without  difficulty. 
The  movements  of  the  setae,  in  creeping,  are  not  independent  Hke  those  of 
vibratile  cilia,  but  are  produced  by  the  contraction  of  the  substance  into 
which  theu'  bases  are  fixed. 

Every  microscopist  has  observed  Ciliata  suddenly  arrest  their  course  and  as 
quickly  reverse  it.  This  phenomenon  Pert}^  calls  '  diastrophy,'  and  asserts 
(op.  cit.  p.  122)  that  this  change  in  movement  is  accompanied  by  such  a 
transition,  that  not  only  does  the  posterior  extremity  become,  for  the  time,  the 
anterior,  but  it  also  acquires  the  size  and  appearance  of  the  latter.  There  is, 
in  his  language,  an  actual  polar  reversion  of  the  organism.  This  peculiarity  is 
observed  among  the  swimming,  but  not  among  the  creeping  Protozoa,  which 
always  advance  with  the  anterior  end  first.  When  Paramecium  versutum  or 
P.  leiicas  becomes  diastrophied,  its  figure  elongates  and  changes  to  cylindrical 


OF  THE  PROTOZOA. CILIATA  .  289 

— the  present  anterior  portion  (fonnerly  the  posterior)  grows  thicker,  whilst 
the  opposite  end  becomes  somewhat  more  pointed.  For  a  few  seconds  the  animal 
swims  about,  revolving  at  the  same  time  upon  its  long  axis,  and  after  sud- 
denly making  a  tiu'n,  reassumes  its  regular  form  and  its  usual  movements. 
It  is  singular  that  the  cilia  of  the  reversed  anterior  cxtremit}^  acquii'e  a  greater 
length  and  strength,  and  act  with  increased  \agour,  whilst  those  at  the  oppo- 
site end  become  inconspicuous  and  passive.  Dming  diastrophy,  moreover, 
rotation  upon  its  long  axis  is  particularly  rapid.  Perty  illustrates  this  pecu- 
liar act  of  diastrophy  in  many  other  species,  of  which  we  may  mention  Para- 
mecium Colpoda,  Colpoda  Ren,  Coleps  hirtus,  Oxytriclia  PeUioneJla,  (fcc. 

A  very  indifferent  conception  can  be  formed  of  the  energetic  ever- varying 
movements  of  the  Ciliata  by  any  attempted  descriptions  of  their  manner 
and  dii'ection.  One  method  is  combined  with  or  rapidly  exchanged  for  an- 
other ;  and  we  see  the  little  beings  not  simply  swimming,  but  revolving  and 
curving  on  themselves  in  a  marvellous  and  beautiful  manner,  to  be  appre- 
ciated only  by  observation. 

Could  we  imagine  the  existence  of  a  will,  or  of  a  power  of  control,  in 
such  tiny  creatures,  we  should  say  that  ciliary  motion  is  at  its  bidding ;  we 
see  it  incessantly  varying  in.  the  same  individual,  both  in  activity  and  power, 
at  one  moment  urging  on  the  moving  atom  at  full  force,  at  another  merely 
revolving  it  rapidly,  at  another  slackened  and  presently  stopped.  These  va- 
riations, too,  appear  not  fortuitous,  but  directed  to  certain  ends — to  the  pro- 
curing of  food,  to  the  avoiding  of  an  obstacle,  or  to  the  escape  from  an  enemy. 
Yet,  on  the  one  hand,  the  belief  in  the  need  of  a  special  organization  for  the 
manifestation  of  volition,  and,  on  the  other,  the  observation  of  very  similar 
movements  in  the  ciliated  cells  of  higher  animals  when  detached  and  free  in 
water,  in  the  Phytozoa  and  in  the  spores  and  filiform  cells  of  plants — are 
circiunstances  which  make  us  hesitate  in  attributing  such  phenomena  to 
any  other  than  purely  physical  forces. 

"There  is  no  sufficient  reason,"  says  Dr.  Carpenter  ('  The  Microscope,'  p. 
476),  "  to  regard  such  actions  as  indicative  of  a  wonderful  adaptation,  on  the 
part  of  these  simple  ciliated  cells,  to  a  kind  of  life  which  enables  them  to  go 
in  quest  of  their  own  nutriment,  and  to  introduce  it,  when  obtained,  into  the 
interior  of  their  bodies." 

Prof.  Owen  remarks,  in  his  lectures  on  the  Comparative  Anatomy  and  Phy- 
siology of  the  Invertebrated  Animals  (1843),  p.  19, — "  If  you  watch  the 
motions  of  the  Polygastric  Infusoria,  you  will  perceive  they  avoid  obstacles 
to  their  progress,  rarely  jostle  one  another ;  yet  it  is  difficult  to  detect  any 
definite  cause  or  object  of  their  movements."  Further  on,  he  writes — "  The 
motions  of  the  Polygastrica  have  appeared  to  me,  long  watching  them  for  indi- 
cations of  volition,  to  be  in  general  of  the  nature  of  respiratoiy  acts,  rather  than 
attempts  to  obtain  food  or  avoid  danger.  Very  seldom  can  they  be  constraed  as 
voluntaiy,  but  seem  rather  to  be  automatic — governed  by  the  influence  of  sti- 
muli Ts-ithin  or  without  the  body,  not  felt,  but  reflected  upon  the  contractile 
fibre — and  therefore  are  motions  which  never  tire.  "We  may  thus  explain 
the  fact  which  Ehrenberg  relates  (not  without  an  expression  of  surprise), 
namely,  that  at  whatever  period  of  the  night  he  examined  the  living  Infu- 
soria, he  invariably  foimd  them  moving  as  actively  as  in  the  day-time  ;  in 
short,  it  seemed  to  him  that  these  little  beings  never  slept." 

Turning  now  to  the  fixed  Ciliata,  we  perceive  that  the  true  VorticeUina, 
not  invested  by  an  external  sheath,  arrange  themselves  under  two  sections, 
according  as  the  stem  is  flexible  and  contractile,  or  non-contractile  and  almost 
or  completely  inflexible.  The  geniLS  VorticeUa  is  the  type  of  the  contractile 
group,  and  Epistylh  that  of  the  non-contractile  and  inflexible.     The  stem 


290  GENERAL  HISTORY  OF  THE  INFUSORIA. 

of  the  genus  first  named  is  always  simple  or  unbranched  (XXVII.  1,  2,  3,  4)  ; 
but  in  that  of  the  other  genera  of  VortkeUina — viz,  Carcliesmm  (XXX.  9) 
and  ZootJiamnium  (XY.  69)  of  the  contractile-stalked  group,  and  Epistylis 
and  Opercularia  of  those  having  rigid  stems  (XXX.  1, 11) — the  young  beings 
produced  by  fission  continue  adherent  to  the  parent  stem,  and  then  proceed  to 
develope  secondary  branching  pedicles  of  theii'  own,  and  in  this  manner  give 
rise  to  compound  ramified  collections  of  polj^^aries.  Since  this  ramification 
is  consequent  on  the  division  of  a  parent-being  into  two,  it  has  necessarily 
a  more  or  less  regular  dichotomous  (forked)  character,  and  will  be  more  com- 
pound the  oftener  the  process  of  fission  has  been  repeated. 

The  stem  produced  by  each  liaK  continues  to  acquii-e  length  and  strength 
until  the  being  which  surmounts  it  begins  in  its  turn  to  undego  self- division, 
when  its  growth  at  once  ceases ;  and  it  undergoes  no  further  change  whilst  it 
exists,  except  in  acquiring  increased  consistence. 

''  The  individuals  on  the  same  stem  have,"  says  Steia  (p.  75),  ''  as  a  rule, 
similar  dimensions,  those  undergoing  fission,  and  therefore  'svider,  excepted. 
At  times,  indeed,  one  may  be  found  smaller  than  its  neighboui'S  ;  but  this  will 
be  traceable  to  some  accidental  cu'cumstance,  such  as  a  less  supply  of  nu- 
triment to  it,  and  is  never  very  considerable.  The  size  of  the  members  of  the 
same  colony  agrees  in  general  with  that  of  the  individual  from  which  the 
whole  have  sprung.  When  the  newly- developed  fission-segment,  after  detach- 
ing itself  from  its  parent,  forthwith  proceeds  to  fix  itself  and  secrete  its  stalk, 
the  newly-developed  colony  will  coincide  in  dimensions  with  that  from  which 
this  animalcule  has  proceeded.  On  the  contraiy,  if  the  detached  member 
enjoys  its  freedom  a  longer  time,  appropriates  nourishment,  and  attains  a 
larger  growth,  the  new  arborescent  poljpary  developed  from  it  will  be  larger 
in  all  respects  than  the  parent  colony.  Hence  it  is,  that  in  the  same  species 
we  have  great  variety  in  the  dimensions  of  individual  members  as  weU  as  of 
colonies ;  and  therefore  the  height  of  the  pedicle,  the  thickness  of  its  branches, 
and  the  size  of  its  individuals  are  useless  as  specific  characteristics." 

The  style  of  ramification  is  equally  devoid  of  constancy  in  the  same  species  : 
for  (to  continue  our  extracts  from  Stein)  "  the  several  branches  may  attain 
an  equal  elevation,  and  so  produce  a  cor^^mb  or  cyme ;  or  the  inner  may  out- 
grow the  outer  branches,  and  the  whole  polypary  resemble  a  bunch  of  grapes 
or  a  panicle ;  or,  as  occasionally  happens,  the  branches  may  be  all  incompletely 
developed,  but  at  the  same  time  bear  numerous  individuals  on  short  stems, 
arranged  in  close  series  on  one  side,  when  there  will  be  a  resemblance  to  an 
ear  of  corn." 

In  the  case  of  Ophrydium  there  is  a  considerable  departure  from  the  ordi- 
naiy  structure  and  arrangement  of  the  polj^aries  of  VorticeUina  and  the  rest 
of  the  Ophryd'ma.  Ehrenberg  considered  the  globular  masses  of  Oplirydium 
to  be  constituted  by  the  cohesion  of  their  gelatinous  sheaths,  and  to  be  the 
consequence  of  their  incomplete  self- division.  This,  however,  seems  to  be 
incorrect ;  for  Stein  (p.  246)  confirms  the  statement  of  Frantzius,  that  the 
gelatinous  ball  is  not  made  up  of  coherent  sheaths,  but  that  the  bodies  of  the 
OpJirydia  are  merely  attached  by  their  tapeiing  posterior  extremities  to  its 
surface,  and  not  imbedded  within  it.  The  animal  sends,  indeed,  a  prolonga- 
tion of  its  tapering  base  some  short  way  within  the  homogeneous  matrix, 
like  a  root ;  and  when  it  forcibly  contracts  itself,  a  shght  depression  of  the 
surface  occurs ;  but  in  no  strict  sense  can  the  gelatinous  excretion  be  called  a 
sheath  or  lorica. 

Although,  in  their  usual  phase  of  being,  the  attached  Ciliata  have  no  power 
of  locomotion,  they  are  nevertheless  capable  of  considerable  relative  move- 
ment.    The  highest  degree  of  this  is  seen  in  the  actively  contractile  stems  of 


OF  THE  PROTOZOA. CILIATA.  291 

Vorticella,  Carclies'mm,  and  Zoothamnium,  and  the  lowest  in  the  nearly  sessile 
VaginicoJa,  and  in  the  rigid-stalked  EpisttjUs.  The  movements  of  the  stems 
of  Vorticelhe  are  most  astonishing  by  their  activity  and  energy.  In  their 
contraction,  which  is  much  quicker  than  extension,  the  pedicle  is  t^\dsted  into 
a  close  spii-al  comparable  to  a  coiled  spring ;  and  besides  this  action,  by  which 
the  animal  is  instantaneously  drawn  do\^Ti  to  the  point  of  attachment,  the 
body  itself  shortens,  and  the  ciliated  head  and  appendages  are  retracted  under 
cover  of  the  general  integument.  The  branched  pedicle  of  Zoothcnnn'mm  is 
less  actively  contractile,  although  still  capable  of  considerable  movement, 
whilst  that  of  Opercularia  and  Epistylis  is  quite  rigid,  or  very  slightly 
flexible,  and  this  in  most  species  only  in  younger  stems,  before  they  are  in- 
durated by  age.  In  Opercularia  herherina  we  have  the  most  marked  example 
of  flexibility  of  the  stem  among  rigid-stalked  genera. 

Apart  from  the  movements  of  the  animacules  dependent  on  their  pedicles, 
others  are  due  to  the  contraction  and  elongation  of  their  bodies,  and  to  the 
retraction  and  extension  of  their  rotarv  apparatus.  In  the  instance  of  Vagi- 
nicola  (XXYII.  11),  of  CotJnmiia  (XXX.  12, 13, 14, 15),  and  of  Tintinnm, 
these,  indeed,  are  the  only  movements  of  which  those  genera  are  capable, — the 
external  sheath  constituting  of  itself  a  safe  house  of  defence  when  the  ani- 
malcule retreats  within  it,  and  thiLS  ofl'ering  a  compensatory  provision  in  lieu 
of  the  locomotive  power  of  the  freely- swimming  Cihata,  or  of  the  actively- 
coihng  spiral  of  Voi^ticeUa.  On  the  other  hand,  when  not  in  retreat,  the  ani- 
malcule outstretches  itself,  and,  advancing  its  ciliated  delicate  head  beyond 
the  hmit  of  the  case  (XXYII.  10,  11),  expands  its  ciliary  apparatus. 

The  animalcules  fi^ed  on  rigid  stems  appear  exposed  to  every  passing 
danger  without  defence ;  natiu'e,  however,  has  fiu-nLshed  them  with  a  firm 
resistant  integument  within  the  anterior  margin  or  peristom,  of  which  they 
can  completely  retract  the  delicate  rotary  disc  and  ciliated  head.  However, 
they  are  not  positively  motionless ;  for  a  certain  latitude  of  motion  is  allowed 
them  by  their  mode  of  articulation,  and  by  the  annular  segmentation  of  the 
posterior  extremity  (XXYII.  16),  in  addition  to  the  possible  contraction  into 
an  ovoid  or  more  or  less  globular  figure.  In  Opercularia  herheriformis  the 
contraction  of  the  body  is  facilitated  by  the  transverse  rugae  which  normally 
exist, — ^whilst  in  Oplirydium  it  is  carried  so  far  that  the  elongated  figure  be- 
comes oval,  and,  the  head  being  retracted,  the  animal  presents  itself  as  an 
inconsiderable  prominence  above  the  sui'face  of  the  gelatinous  mass  it  rests 
upon.  The  absence  of  a  protecting  sheath  in  this  genus  is  partly  compen- 
sated for,  fiu'ther,  by  the  aggregation  of  the  Ophrydia,  since  the  globose  mass 
produced  is  of  itself  a  security,  and  is  rendered  still  more  so  by  its  revolving 
movements,  the  result  of  accidental  external  forces,  and,  we  may  suppose, 
also  by  the  activity  of  the  animals  projecting  from  its  surface. 

The  VorticeUina  and  Oplirydina  live  as  free  beings  for  a  certain  time  after 
their  production,  whether  by  fission  or  by  gemmation,  or  by  internal  germs 
or  embryos.  In  the  case  of  the  products  by  gemmation  and  fission,  this 
locomotive  power  is  due  to  the  temporary  formation  of  a  wreath  of  cilia  be- 
hind the  posterior  third  of  the  body,  as  mentioned  in  a  preceding  page  ;  and 
it  is  curious  that  it  is  not  then  the  head  which  moves  in  advance,  but  the 
hinder  extremity,  by  which  attachment  is  to  be  presently  made.  There 
seems  to  be  an  object  in  this  backward  progression ;  for  by  it  the  animal  is 
brought  directly  into  contact  with  any  object  to  which  it  can  affix  itself,  and 
its  attachment  made  more  fii'm.  The  part  to  be  attached  is  the  first  to  come 
into  contact  with  the  supporting  medium  ;  and  whether  it  proceeds  to  secrete 
about  itself  a  sheath,  or  to  develope  a  peduncle,  it  finds  itself  rightly  placed 
without  any  revolution  of  the  body. 

r2 


292  GENERAL  HISTORY  OF  THE  INFrSORIA. 

Structure  of  Pedicles. — The  intimate  structm-e  of  the  stem  of  the  Vor- 
ticeUina  is  different  in  the  contractile  and  in  the  rigid  forms.  The  highly- 
sensitive,  contractile,  simple  pedicle  of  the  genns  Vorticella  has  challenged 
especial  study.  It  is  evidently  a  compoimd  structui'e,  consisting  of  a  hollow 
tube  containing  a  cylindiical  band.  The  tube  is  a  portion  of  the  general 
integ-ument,  and  continuous  with  it ;  in  diameter  it  is  uniform  throughout, 
except  at  its  point  of  junction  with  the  body,  where  it  undergoes  a  very  slight 
expansion.  Owing  to  the  excessive  rapidity  of  its  spii-al  contraction,  this  act 
can  ^^dth  difficulty  be  observed,  except  after  the  adcUtion  of  a  weak  solution 
of  corrosive  sublimate,  which  renders  it  so  much  slower  that  its  progress  may 
be  watched.    Ultimately,  indeed,  the  solution  kills  the  animal. 

The  contained  band,  or,  to  borrow  a  term  from  general  anatomy,  the  ''  axis- 
cylinder,"  does  not  fill  the  cavity  of  the  tube,  but  is  disposed  within  it  in  a 
loose  spiral  manner.  Opinion  has  been  much  divided  as  to  the  nature  of 
this  structui-e.  Ehrenberg,  judging  from  its  active  contractility,  pronounced 
it  a  muscle,  and  went  so  far  as  to  represent  it  as  striated,  i.e.  as  belonging  to 
the  liighest- developed  condition  of  muscular  tissue,  which,  however,  com- 
parative anatomy  teaches  us  is  absent  in  the  lowest  classes  of  animals.  Many 
other  writers  have  united  with  Ehrenberg  in  considering  the  band  muscular, 
and  some  few  also  striated,  whilst  others,  again,  have  regarded  it  as  a  simple 
primitive  contractile  substance,  less  elevated  than  muscle  proper  in  the  range 
of  tissues.  Indeed,  when  we  contemplate  the  contractility  exhibited  by 
certain  plants,  and  can  find  nothing  more  than  spiral  vessels  which  can 
be  conceived  the  seat  of  this  property,  we  are  forced  to  admit  that  muscular 
tissue  is  not  the  only  actively  contractile  element  in  organized  bodies. 

Stein,  after  remarking  that  the  histology  of  the  stem  in  Vorticella, 
Carchesium,  and  Zoothamnium  is  essentially  similar,  proceeds  to  describe  the 
axis-cylinder  as  an  opaque,  solid,  finely-granular  mass,  presenting  delicate 
longitudinal  lines  or  stripes.  In  Vorticella  nehulifera,  V.  convallaria,  V. 
CamjKinula,  and  in  Carcliesiimi  polypinum  (XXX.  9),  it  extends  into  the  body 
as  a  single  tapering  band  or  sti'eak,  and  in  other  Vorticellina  in  two'  such 
diverging  from  one  another,  as  remarked  by  Ehi'enberg,  who  concluded  them 
to  be  two  muscular  cords.  When  the  stem  contracts  spirally,  transverse  lines 
or  stripes  appear  in  the  axis-matter,  which  are  no  other  than  cross  folds,  not 
parallel,  and  most  strongly  marked  on  the  concave  side  (XXX.  10)  ;  they 
have  therefore  no  homology  with  the  transverse  strise  of  muscle.  That  the 
contractile  power  is  dependent  on  the  contained  axis-cylinder  is  shown  by 
the  facts,  that  where  this  is  deficient  at  any  part,  as  not  unfrequently  hap- 
pens in  Zoothamnium,  that  portion  is  ligid,  as  in  Ejnstylis  or  OpercuJaria  ; 
that  when  destroyed  by  maceration,  or  by  chemical  agents,  the  stem  is  out- 
stretched and  remains  immoveable  ;  and  that,  as  is  not  seldom  seen  both  in 
Carcliesium  and  Zoothamnium,  this  axis-matter  may  be  torn  across,  at  one  or 
more  parts,  without  the  external  sheath  being  injured :  the  contractility  is 
destro3'ed,  except  in  that  segment  which  is  still  in  continuous  union  with  the 
body  of  the  animal ;  and  generally  the  pedicle  is  only  so  far  and  so  long  con- 
tractile as  its  axis-cylinder  continues  its  unbroken  connexion  with  the  body. 

"Although,"  observes  Stein  (p.  80),  "these  phenomena  are  in  favour  of 
the  axis-matter  being  a  muscle,  yet  there  are  others  sufficiently  conclu- 
sive against  the  notion.  Eor  instance,  were  the  axis  a  muscle,  its  move- 
ments should  cease  when  it  loosens  its  hold  from  the  object  it  is  affixed 
to  :  but  this,  although  asserted  by  Eckhard,  does  not  happen ;  for  when 
Vorticellce  and  Carchesia  relax  their  hold  and  swim  freely  about  with  their 
stems,  these  last  are  seen  to  actively  contract  in  theii'  usual  spiral  manner, 
and  presently  again  to  extend  themselves.     In  like  maimer  Vorticellce,  when 


OF  THE  PKOTOZOA. CILIATA.  293 

detached  from  their  stems,  alternately  contract  and  extend  their  bodies  ;  and 
yet  no  one  pretends  to  see  any  distinct  lines  or  bands  in  their  interior  to  be 
termed  muscles." 

Stein's  conclusion  therefore  is,  that  the  contained  substance  of  the  stalk  of 
the  contractile  VortkeUina  is  not  muscular,  although  it  is  the  organ  through 
which  the  wiU  of  the  animal  is  exercised  over  the  pedicle.  Fiu'ther,  as  the 
action  of  chemical  reagents  upon  the  enclosing  tube  or  sheath  of  the  pedicle 
coiTcsponds  vdih.  theii'  action  upon  the  cuticle  of  the  body,  so  also  is  there  a 
similar  correspondence,  in  chemical  relations,  between  the  axis-cylinder  and 
the  internal  tissue  of  the  body. 

Czeimak,  in  his  essay  on  the  stem  of  Vorticellce  (ZeitscJir.  iv.  p.  442),  describes 
in  that  of  Carchesium  three  distinguishable  structures: — 1,  the  hyaline 
colourless  sheath  ;  2,  a  yellomsh  contained  fibre  or  band ;  and  3,  a  finelv- 
granular  fibre  lying  parallel  to  the  last  (XXX.  10).  These  thi^e  portions  he 
terms  three  isotropous  helicoids,  ^ith  reference  to  their  spiral  mode  of  con- 
traction. Eckhard  supposed  the  eftective  cause  of  the  contractility  to  consist 
in  the  constant  intimate  connexion  between  the  motions  of  the  stem  and 
those  of  the  body :  but  there  is  no  such  constant  connexion  ;  for  the  ciHary 
wreath  may  be  retracted  frequently  without  any  contraction  of  the  pedicle. 
According  to  Czermak,  the  explanation  of  the  movements  is  to  be  found  in 
the  external  hyaline  fibre  or  tube  being  elastic,  and  tending  naturally  to  keep 
the  stem  outstretched,  whilst  the  yellow  contained  filament  is  contractile 
serving  to  thi^ow  the  stem  into  folds, — the  one  consequently  antagonistic  to 
the  other.  To  the  third  or  granular  element,  he  is  disposed  to  attribute  only 
a  vegetative  function.  The  elastic  force  of  the  stem  is  constant,  whilst  the 
contractile  is  momentary  in  operation ;  the  result  of  this,  coupled  with  its 
tubular  structiu^e,  aff'ords  an  explanation  of  the  particular  spii^al  mode  of 
contraction.  This,  Czeimak  has  taken  much  pains  to  elucidate  by  reference 
to  physical  laws,  and  an  appeal  to  arguments  which  we  deem  unnecessary  to 
reproduce  here. 

More  recently,  the  idea  of  the  muscular  nature  of  the  axis-cylinder  of 
Vorticellce  has  been  re\ived  by  Lachmann  (oj).  cit.  p  229),  who  does  not 
hesitate  to  call  it  a  stem-muscle,  and  ^'  cannot  allow  any  value  to  Stem's 
objection,  that  it  stUl  contracts  even  when  the  stem  is  not  attached  to  another 
object ;  for  the  muscle  does  not  thus  loose  its  insertion,  as  it  is  attached  to  the 
sheath  of  the  stem  itself  by  its  hinder  extremity,  and  not  to  the  foreign  object." 
This  reply  to  the  objection  seems  perfectly  admissible,  although  for  our  part 
we  do  not  at  all  perceive  the  necessity  of  regarding  the  axis-matter  as  muscle 
in  the  exact  sense  of  the  term,  even  if  it  is  in  function  homologous  Tvdth  that 
compound  tissue  of  higher  animals.  A  further  statement  made  by  Lachmann 
is,  that  the  muscular  tissue  of  the  stem  extends  upwards  into  the  body,  where 
it  joins  with  the  supposed  muscular  lamina  lining  the  cortical  laj'er. 

The  manner  in  which  the  axis-cylinder  is  produced  and  disposed,  is  shown 
by  Stein  to  afi'ord  a  distinction  between  the  allied  genera  Carchesium  and 
Zoothamnium.  In  the  former,  each  branch  developes  its  own  canal  and  its 
own  central  substance,  so  that  neither  of  them  is  directly  continuous  with  the 
canal  or  the  contractile  matter  of  those  portions  previously  formed  (XXX.  9)  ; 
in  Zoothamnium,  on  the  contrary,  both  the  sheath  and  the  axis-cylinder  of 
the  stalk  are  continuous  throughout  the  ramified  pol^qDidom  (XII.  69).  It 
is  in  this  genus,  particularly,  that  the  oldest  portion  of  the  stem  is  often  solid  : 
indeed  imperfectly-developed  stems  occur,  in  which  after  one  or  more  divisions 
this  same  solid  and  rigid  condition  is  seen.  Such  varieties,  as  Stein  points 
out  (o/j.  cit.  p.  218),  are  to  a  certain  extent  difficult  to  distinguish  from  species 
of  Epistylis ;   nevertheless  they  are  never  so  rigid  as  the  latter,  but  admit  of 


294  GENEEAL  HISTORY  OF  THE  INEUSORIA. 

being  curved  and  are  more  elastic,  and,  besides  all  this,  they  exhibit  trans- 
verse folds  or  constrictions,  of  different  depths,  which  are  rendered  still  more 
evident  when  the  animals  contract  and  shorten  themselves  upon  their  stems. 

The  rigid  stems  of  Opercularia  (XXX.  1)  and  EpistyUs  (XXX.  11)  are 
solid,  without  internal  canal  and  contractile  matter ;  fi^equentlj  they  appear 
finely  striated  longitudinally,  and  in  several  species  {e.  g.  OiDercidaria  articu- 
lata)  present  transverse  lines  (XXX.  1),  along  which  they  more  readily  fracture. 
These  last  are  commonly  described  as  articulations  or  joints ;  but  they  occur  at 
irregular  distances,  and  are,  even  in  the  same  species,  neither  constant  in  num- 
ber, in  distinctness,  nor  in  distribution,  and  are  consequently  worthless  in 
specific  descriptions. 

The  substance  of  these  rigid  stems  is,  however,  not  imiform,  but  divisible 
into  a  cortical  layer  and  an  inner  or  medullary  substance.  This  is  manifest  by 
the  fact  of  the  transverse  lines,  which  become  more  evident  during  the  Hmited 
undulating  movements  of  the  stem,  penetrating  only  through  its  cuticle  or 
covering.  "  On  the  addition  of  concentrated  sulphuric  acid,"  says  Stein  (p. 
112),  "  the  pedicle  swells  up,  and  both  longitudinal  stria)  and  transverse  lines 
or  folds  vanish,  the  whole  mass  appearing  homogeneous  and  hyaline.  Tincture 
of  iodine  coloiu's  it  yellow  ;  but  sulphuric  acid  being  added,  it  is  again  rendered 
colourless." 

CoMPOUN^D  Special  Oeoans  of  Locomotion  axd  Peehensioit.     The  Peeistom 

AND  ROTAEY   OR  CiLIlTED  DiSK.       ThE   SpIEALLT-COILED  HeAD   OF  SpIEOCHONA. 

— Before  entering  on  the  description  of  the  internal  organization  of  the  Ciliated 
Protozoa,  there  is  one  set  of  organs,  belonging  to  the  important  genera  Vortl- 
cellina  and  Ophrydina  (Ehr.),  which  demands  our  attention.  The  organs  in 
question  are  appiu-tenances  of  the  head,  and  consist  of  a  cihaiy  wi^eath  and 
a  retractile  cihated  disk. 

Ehrenberg  appeai-s  not  to  have  recognized  the  existence  of  the  ciliated  disk 
as  a  special  structure  ;  for  in  his  several  generic  descriptions  of  VorticelUna 
and  OiDlirydina,  he  speaks  of  the  head  as  simply  crowned  by  a  wreath  of 
cilia,  more  prominent  at  one  part,  which  he  called  the  forehead,  and  inter- 
rupted at  one  spot  by  a  sort  of  gap  where  the  oral  apertiu'e  is  placed.  Stein's 
researches,  however,  show  clearly  that  the  armatui'e  of  the  head,  in  most  of  the 
genera  of  those  families,  is  much  more  complex.  The  excepted  genera  are 
Stentor,  Tricliodina,  Urocentnmi,  and  Tintinnus,  which  are,  in  fact,  not  true 
members  of  the  family.  Stentor  furnishes  an  example  of  the  structui'e  of 
cihary  wreath,  presumed  by  Ehi^enberg  to  belong  to  all  VorticelUna,  being 
in  fact  a  single  line  of  cilia  fringing  the  periphery  of  the  head,  and  bending 
do^vn  spii-ally  to  the  mouth  (XXYIII.  16 ;  XXIX.  7,  8).  Tricliodina  is 
very  curiously  fringed  with  an  anterior  and  posterior  wreath  of  cilia,  and 
has  besides  a  fii'm  collar-like  ring,  within  which  is  a  circlet  of  stiff  uncini 
(XXIX.  15,  16,  17). 

In  the  genus  Vorticella  the  apparatus  is  most  simple  ;  it  is  shghtly  more 
developed  in  Ojjihrydium  and  in  Vaginicola,  still  more  so  in  Eijistylis,  and 
most  of  all  in  Ojyercidaria  and  Lagenophrys ;  lastly,  in  Sjnrochona,  Chcetospira, 
and  Lagotia,  totally  exceptional  forms  occur.  "When  examined  closely, 
Lachmann  says  (A.  N.  H.  1857,  xix.  p.  118),  we  find  the  wreath  is  a  spiral, 
and  not  a  complete  circle  (XXIX.  1,  2,  3,  4,  7).  It  begins  in  the  vicinity 
of  the  orifice  of  the  vestibule,  nms  above  it  towards  the  left,  and  roimd  the 
margin  of  the  ciliaiy  disk ;  but  before  it  again  reaches  its  starting-point, 
it  descends,  upon  the  stem  of  the  rotary  organ,  into  the  commencement  of 
the  digestive  apparatus  (i.  e.  the  vestibiilum) ....  The  portion  of  the  ciliaiy 
spiral,  which  is  outside  the  vestibulum,  is  not  of  equal  length  in  all  Vorticel- 
Una ;  in  many — VorticeUa,  Oarchesimn,  Zoothamnium,  ScyphicUa  (XXIX.  3), 


OF  THE  PROTOZOA. CILIATA.  295 

Trkhodina  (XXIX.  15,  17),  some  species  of  Epistyl'is,  ifec. — it  scarcely  de- 
scribes more  than  one  circuit  round  the  disk,  whilst  in  Oj^ercularia  articulata 
and  EpistyVis  Jiavicans  it  runs  round  the  disk  three  times,  and  in  other  forms 
the  length  lies  between  these  two  extremes.  This  portion  consists  of  a  double 
row  of  cilia ;  those  of  the  outer  row  are  usually  somewhat  shorter  than  those 
of  the  inner,  and  inserted  upon  the  ciliary  disk  nearly  in  the  same  line,  but  at  a 
different  angle,  as  they  appear  to  be  far  more  strongly  bent  outwards.  In 
the  Ycstibulum  and  oesophagus  the  cilia  appear  to  stand  in  a  single  row. 
The  peristom  bears  no  cilia ;  those  represented  upon  it  by  Stein  belong  to  the 
outer  series  of  cilia  of  the  disk,  or  to  that  portion  of  the  spii^al  which  descends, 
on  the  stem  of  the  rotatoiy  organ,  into  the  vestibulimi.  The  latter  also, 
perhaps  in  conjunction  with  the  bristle  above  mentioned,  appear  to  have  been 
what  induced  Ehrenberg  to  suppose  the  existence  of  a  frilled  lower  Up  in 
EpistyUs  nutans,  and  Stein  in  all  the  Opercularke. 

'^  To  see  the  particulars  above  described,  it  is  peculiarly  advantageous  to 
observe  animals  which  have  died  during  expansion." 

In  Vorticella  (XXYII.  1, 2,  4  ;  XXIX.  1)  we  have  a  truncate  anterior  ex- 
tremity, the  margin  of  which,  i.  e.  the  peristom,  is  ciliated,  expanded,  and 
often  rather  roUed  outwards,  and  has  within  and  rising  .slightly  above  it  the 
rotary  or  ciliated  disk.  This  is  separated  by  a  fissiu"e  from  the  peristom 
(XXYII.  1,  2),  except  at  one  part,  where  the  two  are  continuous,  and  on 
examination  the  disk,  with  its  supporting  stem  narrowing  downwards  and 
outwards  obliquely  into  the  body,  appears  to  be  a  fold  reflected  from  the 
icner  margin  and  surface  of  the  peristom.  The  mouth  opens  at  the  bottom 
of  the  fissure  or  cavity  (the  vestibulum),  and  is  fm^nished  with  several  cilia. 
The  ciliated  disk  when  outstretched  is  elevated  a  little  above  the  peristom, 
but  can  be  retracted  and  covered  in  by  it  completely.  The  peristom,  like- 
wise, can  so  cuiwe  itself  inwards  as  to  include  its  own  cilia  within  the  ring 
of  integument  which  closes  over,  like  a  sphincter,  the  whole  ciliary  ap- 
paratus of  the  head.  The  rotary  disk  has  some  general  resemblance  to 
a  cork  or  plug,  which  can  be  drawn  inwards  by  the  animalcule  itself,  or 
pushed  outwards,  so  as  to  serve,  by  its  ciliated  margin,  to  produce  a  vortex  in 
the  fluid,  and  thereby  fulfil  the  piu^DOse  of  a  prehensile  or  purveying  organ, 
in  addition  to  its  locomotive  power  when  the  VorticeUa  is  free.  The  tapering- 
basis  of  the  disk  ends  below  in  the  general  cavity  of  the  body,  and  is  held  in 
situ  by  its  retractor  fibres,  which  proceed  to  it  from  the  sides  of  the  animal- 
cule posteriorly.    Its  interior  is  continuous  with  the  general  cavity  of  the  body. 

The  unfolding  of  the  ciliary  apparatus  of  the  head  is  more  gradual  than  the 
retraction  ;  and,  so  to  speak,  the  animal  seems  to  feel  its  way  by  fii\st  everting 
a  portion  of  its  delicate  peristom  (according  to  our  own  observation,  in  a  sinuous 
manner)  along  with  a  few  of  its  stronger  cilia,  before  expanding  the  rest. 

In  Oplirydium  (XXX.  5),  the  disk  is  rather  more  convex  on  its  surface, 
and  advances  somewhat  higher  above  the  peristom,  but  in  all  essential  parti- 
culars resembles  that  of  Vorticella.  On  the  retraction  of  the  disk,  the  peri- 
stom contracts  above  it  into  a  short  cylinder,  and  the  head  swells  out  in  a 
globose  manner  (XXX.  6).  Between  Oplirydium  and  Vaginicola  (XXYII. 
11)  there  is  a  close  resemblance  in  the  conformation  of  the  ciliated  organs, 
except  that,  in  the  latter,  the  act  of  retraction  agrees  rather  ^dth  that  of 
Vorticella  than  with  Ophrijdium. 

A  truncated,  thickened,  somewhat  everted  peristom,  fringed  with  cilia 
(this  Lachmann  denies,  see  above),  belongs  to  Epistylis  (XXX.  11)  as  well  as 
to  the  above-named  genera,  and  to  Carchesium  (XXX.  9)  and  Zoothamnium. 
It  has  also  a  similar  rotary  disk,  only  rather  more  developed,  and  its  stem 
short  and  thick. 


296  GENERAL  HISTOEY  OF  THE  INFTJSOEIA. 

In  Opercularia,  on  the  contrary,  the  peristom  is  neither  ciliated,  expanded, 
nor  everted  in  a  campamilate  manner,  but,  by  the  tapering  of  the  anterior 
thii'd  of  the  body,  is  narrow  (XXX.  1,  37),  and  frequently  throT\Ti  into  longi- 
tudinal rugae,  and  withal  simply  truncate.  Further,  the  disk  has  a  fiat 
sui'face,  and  is  supported  on  a  long  stem  which  tapers  internally  to  a  fine 
extremity ;  and  the  whole  organ  assumes  a  ti^nmpet-like  figure  (XXX.  1  «, 
2  a,  d).  Moreover,  instead  of  an  infundibuliform  fissure  conducting  to  an 
oral  aperture  or  entrance  to  the  ahmentary  canal,  there  is  a  wide  throat  or 
pharjTix,  occupying  almost  the  whole  diameter  of  the  peristom,  having  its 
border  extended  upwards  in  the  form  of  a  free  edge  (XXX.  2,  3),  which 
Stein  calls  an  under  lip,  in  contradistinction  to  the  rotary  disk,  which  Ehi-en- 
berg  represented  to  be  a  forehead  and  upper  lip. 

The  tapering  stem  of  the  disk  bounds  one  side  (the  upper)  of  the  pharynx, 
and  by  its  narrow  extremity  communicates  with  the  general  cavity  of  the 
body.  The  flat  disk  itseK  is  surrounded  by  two  or  three  concentric  rows  of 
long  cilia,  and  when  di^awn  inwards  suffices,  with  little  aid  from  the  constric- 
tion of  the  peristom,  to  close  that  opening.  When,  however,  contraction  is 
more  forcible  and  complete,  this  process  is  entirely  retracted,  and  the  peristom 
closed  above  it  (XXX.  37).  When  in  this  condition — and  this  Is  true  also  of 
the  other  allied  genera, — the  only  indication,  as  before  mentioned,  of  the 
ciliary  apparatus  of  the  head  is  an  irregularly-shaped  streak  or  space,  in 
which  cilia  may  still  be  discerned.  This  irregular  space  is  nothing  more 
than  the  remnant  of  the  pharjTigeal  cavity  not  occupied  by  the  retracted 
organs. 

On  the  retraction  of  the  rotaiy  disk  a  portion  of  its  contents  is  transfeiTcd 
from  the  expanded  free  extremity  into  its  stem,  the  quantity  so  removed  being 
in  dii^ect  ratio  with  the  degree  of  contraction  ;  when  this  is  considerable  the 
trumpet-like  process  appears  like  a  mere  internal  lobe  (XXX.  37  b,  li). 

In  Lagenoplirys  the  peristom  is  pecuhar  in  being  adherent  to  the  narrow 
two-hpped  aperture  of  the  sheath ;  the  diameter  of  the  two  orifices  is 
consequently  equal.  Prom  the  peristom  a  long  tnimpet-shaped  rotary  organ 
projects,  similar  to  that  of  Opercularia  (XXX.  29,  32,  33,  34). 

The  most  suigular  conformation  of  the  head  occurs  in  a  new  member  of 
the  VorticeUina,  described  and  figiu^ed  in  Steiu's  admii^able  monograi^h  (p.  205) 
under  the  name  of  Spirocliona  (XXX.  17,  27, 28).  In  this  the  ordinary  struc- 
ture of  the  head  is  entirely  departed  fi'om ;  and  we  have  in  its  place  a  con- 
voluted spii^al  membrane  or  lamella,  rolled  inwards  around  a  sohd  central 
axis,  forming  a  sort  of  exaggeration  of  the  single  spiral  wreath  of  Stentor. 
In  full-grown  specimens  of  Sjjir.  gemmipara,  two  complete  cii'cuits  (XXX. 
17)  are  made  by  the  lamella,  each  of  which  is  morphologically  the  same  as 
the  ciliated  peristom  expanded  and  flattened  out.  The  suifacc  is  clothed 
-svith  ciha  ;  and  at  its  termination  in  the  body,  near  the  axis  of  the  spu^al,  is 
placed  the  mouth,  into  which  foreign  substances  are  rapidly  transmitted  by 
the  action  of  the  cilia. 

Among  the  several  members  of  the  families  j^assed  in  review,  we  have  seen 
a  considerable  range  in  the  complexity  of  the  cihary  ^vreath  ;  and  on  extending 
our  examination  to  other  genera,  intermediate  gradations  in  structiu'e  may 
be  discovered.  Thus,  through  the  simj)le  spirally- ciu'ved  wreath  of  Stentor 
(^XXIX.  7),  we  have  a  connecting  link  between  Vorticella,  on  the  one  hand,  and 
several  genera,  of  which,  in  respect  of  the  cihary  armature  of  the  head, 
TricJiodina  may  be  taken  as  the  representative. 

Chcetospira,  a  new  genus  instituted  by  Lachmann  (A.  N.  U.  1857,  xix.), 
has  a  ciliary  apparatus  so  abnormal  and  peculiar,  that  it  would  seem  rather  a 
representative  of  another  family  than  one  of  the  VorticeUina.     The  anterior 


OF  THE  PEOTOZOA. CILIATA.  297 

portion  of  the  body  is  much  elongated,  and  supports  a  ciliated  process,  when 
fully  extended,  straight  and  of  a  sword-shaped  figure,  fringed  along  one  side 
and  at  the  end  with  cilia  (XXIX.  5)  ;  but  when  in  active  vibration  and  t^virl- 
ing  the  animalcide  onward  in  a  spii'al  manner,  the  greater  part  of  this  ciliated 
process  becomes  ciuwed  like  a  sickle  (XXIX.  6). 

Another  bizarre  form  of  ciHary  apparatus  is  exhibited  by  the  genus  Lagotia, 
described  by  Dr.  Strethill  Wright  as  a  member  of  the  family  Ojplirydina. 
The  head  of  this  animal  protrudes  a  pair  of  horn-like  divergent  processes, 
fringed  around  with  cilia,  flat  or  folded  longitudinally,  and  straight  or  recurved 
at  the  extremities.  These  ciliated  appendages,  together  with  the  elongated 
body  they  surmount,  enjoy  a  very  great  latitude  of  motion  by  alternate  con- 
traction and  extension,  and  by  curving  and  tmsting  in  different  directions. 
The  mouth  lies  in  the  angle  between  the  processes.  The  whole  being  may  be 
said  to  stand  in  a  position,  mth  regard  to  the  rest  of  the  VorticelUna  and 
Ophrydina,  similar  to  that  of  Stephanoceros  to  the  other  Rotatoria. 

INTEENAL  OKaANIZATION  OF  THE  CILIATED  PROTOZOA. 

STJBTEGUMEIfTARY    LAYER;     CHLOROPHYLL;    ThREAD-CELLS  ;    MtJSCLES. Sub- 

jacent  to  the  cuticle  is  a  layer  of  granules  and  smaU  globules,  which  is 
often  spoken  of  as  a  second  lamina,  just  as  the  cutis  vera  in  higher  animals 
is  of  the  cuticle.  Its  thickness  is  considerable  ;  it  is  hyaline,  and  more  con- 
sistent than  the  contents,  and,  although  homogeneous  itself,  contains  a  multi- 
tude of  granules,  and,  at  least  in  several  genera  {e.  g.  Paramecium,  Oplirydium, 
Nassida),  numerous  chlorophyll-vesicles,  often  so  thickly  disposed  as  to  impart 
a  Hghter  or  deeper  green  colom-  to  the  animal  (XXIX.  28).  In  young,  and 
also  in  very  old,  specimens  this  coloui^iag-matter  is  wanting,  and  only  colom^- 
less  granules  with  a  dark  outline,  resembhng  small  fat-particles,  present. 

In  Mr.  Carter's  phi^aseology  this  cortical  lamina  bears  the  name  of  the 
"  diaphane,"  and  is  said  to  lie  beneath  the  ^'  pellicula,"  but  not  to  be  secreted 
from  it.  The  j)roperty  of  contractility  resides  in  it,  whence  it  becomes  so 
far  analogous  to  the  muscle  or  flesh  of  animals,  that  to  it  the  term  '  sarcode  ' 
may  most  appropriately  be  apjolied.  Dujardin,  however,  who  first  employed 
this  term,  did  so  to  designate  the  entire  component  organic  mass  of  Protozoa  ; 
but  as  later  observers  seem  to  make  out  the  presence  of  a  somewhat  dis- 
similar substance,  of  a  much  looser  and  more  mucilaginous  consistence,  sur- 
rounded by  the  contractile  layer  in  question — in  other  words,  within  the 
so-called  abdominal  cavity — we  feel  quite  justified  in  limiting  its  signification 
as  we  have  done. 

That  the  cortical  layer  alone  is  contractile,  Lachmann  considers  {A.  N.  H. 
1857,  xix.  p.  126)  to  be  shown  by  the  fact,  that  ''  in  torn  Infusoria  fragments 
of  it  not  imfrequently  contract,  whilst  the  internal  mass,  the  *  chyme,'  which 
flows  out,  never  does  so."  Its  contractions  eifect  the  various  alterations  in 
the  figure  of  animalcules,  whilst  by  its  greater  consistence  compared  with  the 
abdominal  contents,  and  its  fixity  as  a  layer  subjacent  to  the  cuticle,  it  affords 
a  surface,  and  even  a  nidus,  for  the  attachment  of  the  nucleus  and  contractile 
vesicle,  which  it  therefore  serves  to  retain  in  situ,  not-withstanding  the 
opposing  forces  of  the  circulatory  current  and  of  particles  of  food  propelled 
against  them  (see  section  on  Cu'culation).  To  demonstrate  this  quiescent 
cortical  lamina  and  the  inner  moving  stratum  also,  chromic  acid  affords  the 
most  eff'ective  means. 

The  cavity  enclosed  by  the  cuticle  and  subjacent  cortical  lamina  is  occupied 
by  an  almost  fluid  matter,  for  which  the  term  "  abdominal  mucus  "  is  suggested 
by  Carter,  and  that  of  ''  chjTue  "  by  Lachmann,  the  former  we  esteem  the 
better,  although  it  imperfectly  represents  the  actual  state  of  things ;  for  in 


298  GENERAL  HISTOliY  OF  THE  INFUSORIA. 

these  central  almost  fluid  contents,  two  portions  are  distinguishable — ^one 
occurring  as  a  stream  moving  around  the  animalcule,  within  and  upon  the 
cortical  lamina,  the  other  as  a  thinner  central  medium,  apparently  quiescent, 
and  in  direct  communication  with  the  siuTounding  water  through  the  channel 
of  the  ahmentary  tube  and  mouth.  To  the  first  only  of  these  two  portions 
Lachmann's  term  '  chyme '  is  rightly  applicable,  since  it  no  doubt  represents 
the  nutritive  material  di^a"WTi  fi'om  the  alimentary  matters  swallowed,  and  to 
the  elaboration  of  which  the  watery  fluid  of  the  centre  most  likely  contributes. 
Both  portions  contain  food-vesicles,  granules,  and  molecules  ;  but  the  former 
possesses  them  in  much  greater  abundance.  When  an  animalcule  dies,  the 
central  contents  are  the  first  to  escape,  streaming  forth  from  the  mouth  as  a 
diffluent  film  with  granules  and  molecules  imbedded  in  it ;  a  similar  discharge 
and  "  diffluence  "  also  ensue  when  the  protecting  envelopes  are  torn  through, 
and  the  more  so  when  some  pressui^e  is  at  the  same  time  exerted. 

The  following  quotation  from  Lachmann  elucidates  veiy  well  several  points 
concerning  the  contents  of  the  body  in  general.  ''  \\Tien,"  he  writes  {op.  cit. 
p.  126),  "  an  Infusorium  is  sucked  out  by  an  Acineta,  the  cortical  layer  or 
parenchyma  of  the  body  may  often  contract  for  a  long  time,  and  the  con- 
tractile vesicle  placed  in  it  may  also  continue  its  contractions  for  hom^s ;  nay, 
I  have  observed  a  Stijlonycliia,  which,  although  a  considerable  part  of  its 
chyme  had  been  sucked  out  of  it  by  an  Acineta,  still  underwent  division,  so 
that  one  of  the  gemmules  of  division  swam  away  from  it  briskly,  and  only 
the  other  half  of  the  old  animal  was  destroyed.  This  appears  also,  to  a  cer- 
tain extent,  to  prove  that  the  mass  sucked  out  does  not  represent  the  time 
parenchyma  of  the  body  ;  and  as  it  only  fills  the  large  cavity  of  the  body  in 
the  form  of  a  tenacious  fluid  mass,  and  becomes  mixed  with  the  nutritive 
matters,  especially  when  no  small  masses  are  formed,  it  is  certainly  the  most 
natm^al  course  to  regard  it  as  chyme.  It  cannot  be  urged  against  this  view, 
that  in  those  Infusoria  which  contain  clilorophy  11- corpuscles  in  the  substance 
of  their  bodies,  we  sometimes  meet  \\ith  single  corpuscles  in  the  rotating 
mass,  as  they  may  certainly  be  easily  loosened  from  the  parenchyma,  and 
thus  get  into  the  chyme-mass.  The  nucleus,  indeed,  projects  into  the  chyme- 
mass  ;  but  as  a  general  rule  it  appears  to  be  affixed  to  the  parenchyma  of 
the  body,  as  we  do  not  see  it  rotate  with  the  chyme-mass :  in  Opercidaria 
herherina,  Stein  sometimes  saw  the  nucleus  moved  a  httle  out  of  its  previous 
position  by  a  mass  of  food  striking  against  it ;  but  as  it  soon  retm^ned  again 
to  its  position,  this  rather  speaks  for  than  against  its  attachment." 

Imbedded  ^vithin  the  cortical  layer  a  collection  of  remarkable  structui'es  is 
discoverable  in  many  species — for  instance,  in  Paramecium,  Oj^hi^yoglena,  and 
Bursaria — known  under  the  name  of  thread- cells  or  trichocysts  (XXXI.  1-4). 
We  are  indebted  to  Prof.  AUman  for  the  minute  and  complete  examination  of 
these  bodies  (J.  M.  S.  1855,  iii.  p.  177).  He  behoves  it  was  these  structures 
which  Cohn  represented  (as  mentioned  in  a  previous  page)  to  be  exceedingly 
long  cilia,  and  which  Stein,  in  criticising  Cohn's  account,  affirms  to  be  cilia  of 
ordinary  length,  but  appearing  abnormally  lengthened  under  external  circum- 
stances, such  as  the  addition  of  strong  acetic  acid.  Prof.  Allman's  description 
is  the  best  we  have : — 

"When  Bursaria  leucas  is  examined  under  a  sufficiently  high  power, 
minute  fusiform  bodies  may  be  detected  thickly  imbedded  in  its  walls. 
These  bodies  are  perfectly  colouiiess  and  transparent ;  they  ai^e  about  the 
-gJL-th  of  an  inch  long,  and  may  easily,  even  without  any  manipulation,  be 
^dtnessed  at  the  margin,  where  they  are  seen  to  be  arranged  perpendicularly 
to  the  outhne  of  the  animalcule,  while  on  the  siuface  turned  towards  the 
observer  the  extreme  transparency  and  want  of  colour  render  them  inrisible 


OF  THE  PEOTOZOA. CILIATA.  299 

against  the  opaque  background,  and  it  becomes  necessary  to  crush  the 
animalcule  beneath  the  coveiing  glass,  so  as  to  press  out  the  green  globules 
which  it  contains,  in  order  to  bring  the  fusiform  bodies  into  view.  To  these 
bodies  I  propose  to  give  the  name  of  tricliocysts. 

"  As  long  as  the  animalcule  continues  free  from  annoyance,  the  trichocysts 
undergo  no  change  ;  but  when  subjected  to  external  irritation,  as  occurs  diu'ing 
the  diying  away  of  the  siuTounding  water,  or  the  aj^plication  of  acetic  acid 
or  other  chemical  irritant,  or  the  too  forcible  action  of  the  compressor,  they 
become  suddenly  transformed  into  long  filaments,  which  are  projected  fi'om 
all  parts  of  the  suiface  of  the  animalcule ;  and  it  is  these  filaments  which, 
being  mistaken  for  cilia  by  Cohn  and  Stein,  gave  rise  to  the  erroneous  views 
just  mentioned. 

''  The  rapidity  with  which  this  remarkable  change  is  efi'ected,  joined  \di\\ 
the  great  minuteness  and  transparency  of  the  object,  renders  it  extremely 
difficult  to  follow  it ;  and  for  a  long  time  I  could  only  satisfy  myself  of  the 
fact  that  the  fusiform  bodies  were  suddenly  replaced  by  the  projected  fila- 
ments. After  continued  observation,  however,  I  at  last  succeeded  in  mt- 
nessing  the  principal  steps  in  the  evolution  of  the  filament. 

"  It  is  not  difficult,  by  rapidly  criLshing  the  animalcule,  to  force  out  some 
of  the  trichocysts  in  an  unchanged  state.  If  the  eye  be  now  fixed  on  one  of 
the  isolated  trichocysts,  it  will  most  probably  be  seen  after  the  lapse  of  a  few 
seconds  to  become  all  at  once  changed  with  a  jDeculiar  jerk,  as  if  by  the  sudden 
release  of  some  previous  state  of  tension,  into  a  little  spherical  body.  In  this 
condition  it  will  probably  remain  for  two  or  three  seconds  longer,  and  then  a 
spiral  filament  wiU  become  rapidly  evolved  from  the  sphere,  apparently  by 
the  rupture  of  a  membrane  which  had  previoiLsly  confined  it,  the  filament 
imrolling  itself  so  quickly  that  the  eye  can  scarcely  follow  it,  until  it  ulti- 
mately hes  straight  and  rigid  on  the  field  of  the  microscope,  looking  like  a 
very  fine  and  long  acicular  ciystal. 

"  This  remarkable  body,  when  completely  evolved,  consists  of  two  portions 
— a  rigid  spiculum-like  portion  acutely  pointed  at  one  end,  and  continuous 
at  the  opposite  end  mth  the  second  portion,  which  is  in  the  form  of  an  ex- 
cessively fine  filiform  appendage  less  than  half  the  length  of  the  spiculum : 
this  second  portion  is  generally  seen  to  be  bent  at  an  angle  on  the  fii^st,  and 
is  frequently  more  or  less  curved  at  the  free  end.  The  form  of  the  evolved 
trichocysts  is  best  observed  in  such  as  have  floated  away  towards  the  margin 
of  the  di^op  of  water,  and  are  there  left  diy  by  the  evaporated  fluid.  In 
many  of  them  the  filiform  appendage  was  not  visible ;  and  they  then  merely 
presented  the  appearance  of  a  simple,  long,  fusiform  spiculum. 

''  The  resemblance  of  the  organs  now  described,  to  the  well-known  thread- 
cells  of  the  Polypes  and  of  certain  other  loAver  members  of  the  animal  king- 
dom, is  obvious.  That  they  are  entirely  homologous,  however,  wdth  these 
bodies  we  can  scarcely  yet  assert.  Their  origin,  at  least,  appears  to  be 
different ;  for,  if  we  admit  the  unicellular  structiu-e  of  the  Infusoria,  we  have 
the  trichocysts  apparently  developed  in  the  substance  of  the  ceU-wall,  instead 
of  being  produced  in  special  ceUs,  as  we  know  to  be  the  case  with  the  thread- 
ceUs  of  the  Polypes." 

These  structuiTS  have  also  arrested  the  attention  of  Oscar  Schmidt, 
Leuckart,  and  Lachmann.  The  second-named  observer  surmised  them  to 
be  ''  poison  organs  ;  "  and  very  probably  they  have  a  defensive  pm^pose,  for  this 
is  suggested  both  by  AUman's  history  of  them,  and  by  Lachmann's  observa- 
tions {op.  cit.  p.  126,  in  foot-note)  "  of  similar,  but  much  thicker  corpuscles, 
which  presented  a  deceptive  resemblance  to  the  urticating  organs  of  the 
Campanularia;,  in  an  animal  li^ing  as  a  parasite  "  upon  individuals  of  that 


300  GENERAL  HISTORY  OF  THE  INFUSORIA. 

family  of  Polypes,  and  **  which  is  probably  to  be  referred  to  the  Acinetina. .  .  . 
In  the  oval  embryos,  ciliated  on  one  side,  which  were  squeezed  out  of  the  body 
of  the  mother,  we  were  enabled  to  convince  oiu^selves  that  these  coi-puscles 
were  enclosed,  from  two  to  nine  together,  in  a  roundish  proper  vesicle  "  (cell). 

Muscles. — Ehrenberg  presumed  the  existence  of  internal  muscles,  to  ex- 
plain the  varied  and  active  movements  of  the  Ciliata, — a  presumption  required 
by  his  hypothesis  of  the  repetition  of  the  organization  of  higher  animals  in  all 
lower  forms,  but  entirely  unwarranted  by  analogy.  Dujardin  considered  the 
whole  bulk  of  the  body  to  be  composed  of  '  sarcode,'  having  an  inherent  con- 
tractility, and  the  som^ce  of  all  the  movements.  Little  doubt  can  exist  that 
the  cortical  lamina  is  the  seat  of  contractility, — not  that  it  is  muscular  on  this 
account,  but  that,  as  animal  tissue  in  its  simplest  condition,  it  possesses  the 
pro]3erty  of  contractility  as  one  of  the  characteristics  of  such  tissue,  along 
with  others,  such  as  sensibility,  all  which,  in  highly-organized  animals,  have 
severally  their  special  structure  elaborated  for  their  more  complete  operation 
and  independent  action.  In  short,  in  the  language  of  physiologists,  the 
tissues  in  more  perfect  animals  are  differentiated,  in  the  lowest  are  not  so. 

This  physiological  fact  being  admitted,  the  existence  of  nerve-fibres  and  of 
nervous  centres,  or  ganglions,  can  be  no  more  than  imaginary.  The  same 
follows  of  the  supposed  organ  of  sense,  the  so-called  eye  of  Glenodinmm, 
which  many  have  concluded  to  be  homologous  with  the  coloui'ed  specks  of 
Protozoa,  of  Euglena,  and  the  like.  Lieberkiihn's  observations  would  lead, 
however,  to  the  conclusion  that  the  eye-speck  of  Ophryoylena  rightly  deserved 
that  epithet,  and  is  something  more  than  a  pigment-spot.  His  account  of  it 
runs  thus  {A.  N.  H.  1856,  xviii.  p.  321)  : — "  Close  by  the  oral  slit,  on  its 
concave  side,  lies  the  pigment-spot.  Its  form  is  extremely  irregular,  some- 
times globular,  sometimes  ellipsoidal,  in  many  cases  toothed.  Ordinarily  it 
is  so  distinct  as  to  be  at  once  perceived ;  sometimes,  however,  it  is  so  small 
that  it  can  only  be  detected  by  close  examination.  In  animalcules  filled  mth 
strongly-refracting  substances  alone,  it  is  always  difficult  to  discover  it.  The 
pigment-spot  of  Ophryoglena  atra  has,  on  the  whole,  more  unifonnity  of  form 
and  magnitude.  If  we  squeeze  do"\vn  an  Opliryoglena  flavicans  between  the 
covering  glass  and  the  slider,  we  find  that  the  pigment-spot  is  composed  of  a 
heap  of  minute,  scarcely  measurable  granules,  strongly  refracting  hght.  I 
never  could  discover  a  lens  in  the  pigment.  All  the  specimens  examined  by 
me  possessed  but  a  single  pigment- spot.  Beside  this  lies  always  a  hitherto 
unobserved  structure,  the  form  of  which  is  perfectly  described  when  we  call  it 
a  -watch-glass  on  a  small  scale.  This  w^atch-glass-hke  organ  is  transparent 
and  colouiless,  and  shows  no  trace  of  fibrous  or  any  other  structure.  The 
cii'cular  base  has  a  diameter  of  about  y-g^jth  of  a  millimetre  ;  its  depth 
amounts  to  about  a  thii'd  part  of  this  diameter ;  the  convexity  is  veiy  con- 
siderable. The  watch-glass-shaped  organ  usually  turns  its  convex  side 
towards  the  pigment-spot ;  its  concave  side  is  directed  towards  the  point  of 
the  head ;  it  does  not  seem  to  be  moveable  by  the  animalcule.  When  isolated, 
it  withstands  the  action  of  water  for  a  longer  time  than  is  usually  the  case 
with  the  other  parts  of  the  body  of  this  Infusorium.  After  Ijing  some  time 
in  water,  it  swells  up  in  some  degree,  and  frequently  becomes  perforated  by 
a  hole  in  the  middle.  The  presence  of  the  w^atch-glass-shaped  organ  is  not 
dependent  on  the  presence  of  a  pigment-spot ;  for  Ophryoglena  atra  possesses 
a  pigment-spot,  but  no  watch-glass-shaped  organ,  while  Bursaria  flava  has 
a  watch-glass-shaped  organ,  but  no  pigment-spot.  In  other  Infusoria  with 
eye-spots,  as  in  the  Euglenm  and  Peridinic^a,  I  have  sought  in  vain  for  this 
organ.     I  have  not  met  with  any  facts  throwing  light  on  its  function." 

Notwithstanding-,  in  the  interior  of  the  Ciliated  Protozoa  there  is  not  an 


OF  THE  PROTOZOA. CILIATA.  301 

actual  homogeneity  of  tissue.  The  act  of  differentiation  is  carried  so  far  that 
certain  distinct  organs  and  parts  become  distinguishable.  Thus  there  is  a 
mouth  or  oral  orifice  for  the  entrance  of  food,  succeeded  by  a  dilated  cavity — 
an  oesophagus  or  pharj-nx,  which  is  contracted  posteriorly  into  a  tubular 
prolongation  of  various  length,  homologous  with  a  digestive  or  alimentary 
tube.  Apart  from  this  rudimentary  alimentaiy  apparatus,  numerous  globular 
or  vesicular  spaces  containing  granular  particles  or  objects  evidently  swallowed, 
are  met  with  in  the  general  loose  contents  of  the  body ;  these  were  the  di- 
gestive sacs,  or  stomach-vesicles,  so  much  insisted  upon  by  Ehrenberg  ;  other 
included  organs  are  the  contractile  vesicle,  a  certain  striated  cylindrical  organ 
in  one  or  two  genera  described  by  Ehrenberg  as  a  dental  cylinder  or  teeth, 
the  nucleus  with  usually  its  nucleolus,  the  red  speck  (eye)  in  Opliryoglena, 
and  in  one  genus  a  pair  of  organs  imagined  by  Stein  to  be  glandular.  To 
these  contents  Carter  adds  spermatozoida,  and  Perty  internal  germs  or  ovules. 

We  have  abeadj^  mentioned  chlorophyll-corpuscles  in  some  genera,  and 
the  general  prevalence  of  fat-vesicles  and  granules  interspersed  within  the 
substance  of  the  body,  or  collected  into  a  layer  as  in  several  of  the  Vorti- 
ceUinci ;  the  collection  of  fat- corpuscles  is  remarkable  in  the  contracted  portion 
or  base  above  the  point  of  attachment,  whether  this  be  by  a  pedicle  or  not. 
"  Perhaps,"  he  adds,  "  the  transverse  annulations  which  are  exhibited  by  the 
bodies  of  some  VortkelUna  are  to  be  attributed  to  muscular  fibres ;  at  all 
events  they  do  not  belong  to  the  skin,  but  to  the  parenchyma  {i.  e.  the  cor- 
tical lamina)  of  the  body." 

Lately,  Lachmann  has  broached  the  hypothesis  that  an  actual  muscular  stra- 
tum lies  within  the  cortical  layer.  He  wiites  {A.  N.  H.  1 857,  xix.  p.  228) — '' I 
was  so  fortimate,  in  common  with  my  friend  Claparede,  as  to  observe  an  indu- 
bitable separate  contractile  layer,  in  which  longitudinal  striae  were  generally 
to  be  detected  in  various  Vorticellina,  in  which  Ehrenberg  states  that  he  saw 
muscular  striae  at  the  posterior  extremity.  It  forms  a  hollow  cone,  the  apex  of 
which  is  situated  in  the  hinder  extremity  of  the  animal,  and,  in  the  contrac- 
tile-stemmed species,  is  produced  into  the  muscle  of  the  stem  :  in  its  apparent 
section  it  of  course  appears  like  two  small  fibres  separating  from  each  other 
like  a  fork — as  which,  indeed,  it  has  hitherto  been  always  regarded,  except 
by  Ehrenberg.  This  layer  is  very  beautifully  seen  in  Epistylis  plicaiilis,  in 
which  we  may  most  completely  convince  ourselves  that  it  is  a  special  stratum, 
which  possesses  contractility.  In  Epistylis  plicatilis,  namely,  duiing  the  con- 
traction of  this  stratum,  the  non-contractile  part  of  the  parenchyma  which 
surrounds  it,  with  the  skin  covering  it,  separates  from  the  contractile  layer, 
and  forms  the  well-known  folds,  whilst  the  contractile  or  muscular  layer  be- 
comes shortened  and  thickened  without  folding." 

Organs  of  Digestion,  Nutrition,  and  Secretion. — To  take  the  several  parts 
or  organs  in  succession,  we  will  first  consider  those  concerned  in  the  processes 
of  digestion  and  nutrition,  beginning  with  the  oral  orifice  or  mouth.  This  is 
variously  situated  in  different  Ciliata,  its  position  having  reference  to  the  figiu'e 
and  the  mode  of  life,  and  being  generally  indicated  by  the  particular  provi- 
sion made  to  secure  a  proper  ciuTcnt  of  water  into  it,  such  as  a  tuft,  a  curved 
row,  or  a  circlet  of  larger  cilia,  a  process  or  a  depression  of  the  body,  the  axis 
of  a  convolution  of  the  surface,  and  the  like.  Thus  in  Lacrymana,  Enchelys, 
Prorodon,  Cohps,  &c.,  it  is  at  the  anterior  narrower  extremity ;  in  Trachelius 
and  AmpTiileptus  it  has  a  similar  position,  but  is  besides  under  cover  of  a 
process  of  the  body.  In  Chilodon  a  still  larger  segment  surmounts  it ;  in 
Nassida,  Paramecium  (XXIX.  28),  and  in  Pleuronema  (Duj.)  it  is  lateral; 
and  lastly,  among  the  Vorticellina  it  is  within  an  involution  of  the  integu- 
ment of  the  head,  called  the  '  vestibulum,'  on  one  side  of  the  cUiated  disk 


302  GENEEAL  HISTOKY  OF  THE  rNTUSORIA. 

(XXX.  1,  2).  The  opening  of  this  vestibule  or  ante-room  to  the  entrance  of 
the  digestive  tube,  i.  e.  the  mouth,  should  not  be  confoimded  with  the  latter, 
as  often  has  been  done.  A  funnel-like  hollovi^  having  the  true  oral  aperture 
at  its  bottom,  is  met  with  in  Paramecium,  and  may  have  the  same  appellation 
extended  to  it.  Among  the  processes  about  the  mouth  facilitating  the  inglu- 
tition  of  food,  we  have  just  alluded  to  the  wreaths,  rows,  and  tufts  of  cilia, 
mostly  large  and  strong  like  bristles,  and  to  special  developments  of  the  sur- 
face of  the  body.  Several  species  possess  a  tuft  of  cilia  almost  indistinguish- 
able from  a  plaited  membrane ;  for  instance,  Colpoda  Ciwullus  (XXIX.  37) 
and  Chilodon  CucuUulus  have  what  Ehrenberg  called  a  tongue,  but  which,  as 
we  have  seen.  Stein  has  resolved  into  a  thick  pencil  of  ciliary  bristles.  A 
similar  structure  prevails  in  PUuronema  and  Alyscum  (Duj.),  in  Cyclidium 
and  Aphthonia  (Perty).  In  Glaucoma  (XXVIII.  4)  and  Cyclidium  marga- 
ritaceum,  "  the  margins  of  the  buccal  orifice  appear,"  says  Lachmann  {op.  cit. 
p.  216),  "to  be  produced  into  two  valves  which  are  in  constant  motion."  A 
special  curved  or  spirally-turned  row  of  cilia  directs  a  cuiTent  into  the  mouth 
in  Stentor,  Spirostomum,  Bursaria,  Chcetospira  (XXIX.  5,  6),  Oxytrichiim, 
Euptlotes,  and  Aspidiscina,  and  a  nearly  straight  row  in  Chilodon  and  Colpoda. 
In  Coleps,  Traclielius,  Enchelys,  and  TracJielocerca,  the  mouth  opens  imme- 
diately upon  the  suiface  without  any  conducting  ciKary  channel,  and  is  sur- 
rounded by  a  simple  circle  of  cilia.  The  mouth  is  protrusible  in  Prorodon  and 
Nassula  (XXVIII.  8,  Qb),  and  not  distinguished  by  any  special  external  array 
of  cilia.  In  the  true  Vorticellina  and  in  the  Ophrydina,  as  above  mentioned, 
the  complex  ciliary  apparatus  dii-ects  the  cm-rent  into  a  cavity,  the  vestibu- 
lum  common  to  both  the  mouth  and  anus ;  and  lastly,  in  Paramecium  the 
cilia  are  uniform  at  all  parts,  and  the  coiu-se  of  food  to  the  mouth  provided 
for  by  a  wide  and  deep  tapering  channel.  In  size  the  mouth  varies  both  in 
different  genera  and  in  relation  to  the  dimensions  of  the  animals ;  but  in  all  it 
is  more  or  less  extensile,  so  that  foreign  particles  or  other  animalcules  are 
engulfed  "within  it  even  when  their  diameter  equals  that  of  the  body  itself. 

The  oral  aperture  opens  below  into  a  rudimentary  digestive  tube  (XXVII. 
1,  10,  11 ;  XXIX.  4  ;  XXX.  1,  11,  29),  fonned  by  an  involution  of  the  ex- 
ternal integument.  It  is  commonly  a  fimnel-shaped  space,  which,  for  the 
sake  of  a  name,  may  be  called  the  pharpix  or  digestive  tube ;  within  this, 
and  especially  near  its  entrance,  a  few  vibratile  cilia  are  mostly  seen,  serving 
by  their  action  to  accelerate  the  onward  transmission  of  the  particles  of  food. 
The  walls  of  this  cavity  are  formed  by  a  special  very  extensile  membrane, 
which,  as  supporting  the  internal  cilia,  may  be  called  a  ^basement  mem- 
brane.' The  pharynx  extends  (as  a  gently  tapering,  mostly  cui'ved,  tube) 
obliquely  inwards  towards  the  centre  of  the  general  cavity  of  the  body,  where 
it  abruptly  ends.  Its  length  is  subject  to  considerable  variation  in  different 
genera.  In  Paramecium  and  allied  genera,  and  in  Oxytrichina,  it  is  short  and 
of  greater  relative  width ;  in  Chilodon,  Nassula,  Prorodon,  and  others  it  is 
continued,  from  the  posterior  extremity  of  the  so-called  cylinder  of  teeth,  far 
into  the  interior.  It  is  also  of  very  considerable  length  in  the  Vorticellhia 
generally,  as  illustrated  by  Epistylis  and  Opercularia  (XXX.  1). 

"  In  Ehrenberg's  families,"  Lachmann  teUs  us  {op.  cit.  p.  217),  ^' Oxy tri- 
china, Euplotes,  and  Aspidiscina  (as  also  in  Stentor,  Bursaria,  and  Spirosto- 
mum), we  meet  with  an  internally  ciliated  oesophagus,  and  a  ciuwed  line 
open  towards  the  right,  composed  of  strong  ciha  leading  to  the  mouth."  This 
oesophagus  alwaj^s  forms  "  an  open  tube,  and  is  often  collapsed  at  fts  inner 
extremity,  and  thus  forms  a  transition  to  the  oesophagus  of  the  following 
groups. 

*'  Many  Infusoria,"  he  continues,  "  have  a  completely  collapsed  oesophagus, 


OF  THE  PROTOZOA. CILIATA.  303 

wliich,  as  forming  a  tube  distinct  from  the  parenchyma  of  the  body,  and 
hanging  freely  in  the  ahmentary  cavity,  is  perhaps  entirely  wanting  in  some 
species ;  at  least,  I  have  hitherto  been  unable  to  detect  it  in  Amrph'deptus, 
most  species  of  Trachelius,  EncJielys,  Coleps,  and  Trachelocerca,  in  which  it 
only  appeared  to  be  a  canal  through  the  parenchyma  of  the  body :  and  these 
are  generally  incapable  of  forming  roundish  morsels  like  the  species  hitherto 
imder  consideration ;  but  they  usually  swallow  larger  particles,  which  then 
pass  separately  into  the  cavity  of  the  body,  often  even  without  being  accom- 
panied by  water.  It  is  very  difficult  to  determine  whether  the  oesophagus  of 
these  animals  is  furnished  internally  with  cilia.  In  some,  such  as  Coleps, 
this  almost  appears  to  be  the  case :  these  STvdm  to  any  slimy  mass,  such  as  a 
dehquescent  Infusorium,  press  the  anterior  extremity  of  the  body  against  it, 
and  open  the  mouth  and  oesophagus,  which  are  usually  closed,  so  as  to  form 
a  wide  canal ;  the  mass  lying  before  the  Coleps  then  j)asses  through  this  canal 
into  the  interior  of  its  body,  apparently  without  any  swallowing  movements 
on  its  part,  so  that  it  can  hardly  be  diiven  in  except  by  ciliary  action.  In 
others,  on  the  contrary,  the  cilia  of  the  oesophagus  appear  to  be  wanting,  as 
in  Ampliileptus,  Enchelys,  Trachelius ;  these  perform  regular  movements  of 
deglutition,  in  order  to  overcome  their  prey,  which  usually  consists  of  Infu- 
soria of  tolerable  size :  they  push  themselves,  as  it  were,  with  swallowing 
motions,  like  the  Snakes,  over  their  prey  (so  that  they  can  very  rarely  be  fed 
with  colour)  ;  and  this  never  forms  stomach-like  morsels,  except  when  it  is 
contained  in  this  form  in  the  Infusoria  devoured." 

Sto:mach-sacs.  The  Polygasteic  Hypothesis. — The  next  organs,  con- 
cerned with  digestion,  to  be  considered,  are  the  stomach-sacs  or  vesicles  of 
Ehrenberg— the  "digestive  globules"  of  Mi\  Carter  (XXYIII.  8/).  The 
former  has  described  these  to  be  disposed  after  certain  definite  types,  which 
fonn  the  basis  of  his  system  of  classification  of  the  Polygastinca.  To  describe 
these  t}^es,  we  must  premise  that  the  families  comprised  in  our  group  of 
Ciliated  Protozoa  represent  the  Enterodela  of  the  Berlin  naturalist,  or  those 
Polycjastrica  having  a  true  alimentary  canal  uniting  the  stomach-sacs  together, 
and  continuous  throughout  from  the  mouth  to  the  assumed  discharging  orifice. 
The  Entei^ocMa  were  subdivided  into  sections  according  to  the  relative  posi- 
tions of  the  mouth  and  anus.  The  first  of  these  was  named  Anop'istliia,  in 
which  the  intestine  was  so  ciuwed  upon  itself  that  its  two  extremities  were 
contei-minous  in  one  aperture,  which  therefore  ser\'ed  the  double  office  of  a 
receiving-  and  a  discharging- orifice.  This  curvature  of  the  intestine  further 
suggested  the  term  Cyclocoela  to  express  it.  The  families  in  this  section  were 
Vorticellina  and  Ophrydina.  The  next  section,  called  Enantiotreta,  included 
animalcules  in  which  the  oral  and  the  anal  apertin-es  were  at  opposite  ends  of 
the  body.  "VMien  this  was  the  case,  the  intestine  might  either  pass  straight 
between  the  openings,  or  be  more  or  less  twisted  in  its  course  :  in  the  former 
ease,  the  Polyyastrica  were  called  Ortliocoela  ;  in  the  latter,  Campylocoela. 
The  EncJielia  and  Colepina  were  the  two  families  of  Enantiotreta.  The  third 
section  was  the  AUotreta,  having  one  orifice  terminal,  and  the  other  lateral, 
and  the  fourth  the  Catotreta,  having  the  two  orifices  on  the  same  side,  not 
terminal  but  abdominal.  The  members  of  these  two  last  sections,  lastly,  had 
either  a  straight  or,  more  commonly,  a  contorted  intestine,  or,  in  other  words, 
were  either  Orthocoela  or  Campyloccela. 

^  Such  is  an  outhne  of  Ehi'enberg's  views  of  the  alimentary  apparatus  of  the 
Ciliated  Protozoa,  as  advanced  in  his  great  work  of  1838,  and  never  since  re- 
called. They  rested  chiefiy  on  some  imperfect  obsei-vations  and  experiments 
made  with  coloured  food,  and  have  failed  to  be  confirmed  in  the  hands  of 
other  mieroscopists.     Although  diligently  sought  after,  no  one  has  been  able 


304  GEITERAL  HISTOEY  OF  THE  INFUSOEIA, 

to  demonstrate  the  intestine  connecting  together  the  several  gastric  canities  ; 
and  what  is  of  more  weight  than  the  absence  of  direct  evidence,  are  certain 
facts  subversive  of  the  notion  that  any  such  tube  exists, — ^dz.  the  irregularity' 
in  the  course  taken  by  the  bolus  of  food  when  transmitted  into  the  interior ;  the 
intermingling  of  the  first-  and  last- swallowed  morsels;  the  movements  hither 
and  thither,  and  the  actual  rotation  within  the  interior  of  the  globules  called 
stomach-sacs ;  the  occasional  coalescence  of  these  sacs,  and  the  not  infrequent 
occuiTence  internally  of  frustules  of  Diatomece  and  joints  of  various  micro- 
scopic Algse  of  great  relative  length  to  the  animalcule  (XXYIII.  31) — some- 
times, indeed,  so  long  as  to  stretch  the  soft  body  itself  (XXYIII.  1).  On  the 
strength  of  these  facts,  coupled  with  the  absence  of  demonstrative  evidence 
of  its  tiTith,  the  polygastric  theory,  and  the  system  of  classification  founded 
upon  it,  have  together  been  all  but  universally  rejected. 

Meyen  was  one  of  the  fii'st  seriously  to  examine  the  statements  of  Ehren- 
berg  :  his  conclusions  were  quoted  at  large  in  our  last  edition.  He  rejected 
the  polygastric  hypothesis  because  he  failed  to  discover  the  connecting  intes- 
tinal tube  represented  by  Ehrenberg,  and,  on  the  other  hand,  detected  the 
rotation  and  coalescence  of  the  assumed  stomachs.  His  views  of  internal 
organization  closely  tally  with  those  now  generally  admitted.  He  recognized 
the  digestive  tube,  the  formation  of  the  globule  of  food  at  its  apparently  open 
termination,  and  its  onward  coui\se  into  the  interior  of  the  animalcule,  where 
it  constituted  one  of  the  supposed  stomach-sacs.  He  seems,  indeed,  to  have 
imagined  a  sort  of  stomach-like  dilatation  at  the  end  of  the  alimentaiy  canal, 
which  served  to  hmit  the  dimensions  of  the  food-globule  there  formed.  The 
circulation  of  the  globules  he  attributed  to  the  force  of  deglutition  and  to 
the  pressiu-e  of  others  subsequently  swallowed :  the  residue  left  after  diges- 
tion he  described  as  escaping  by  an  anus. 

An  extract  from  Mr.  Carter's  valuable  paper  {A.  N.  H.  1856,  xviii.  p.  123) 
may  with  propriety  be  introduced  here.  "  I  cannot,"  he  says,  "  with  some 
others,  think  that  there  is  any  tatestinal  canal  in  the  abdominal  cavitj^,  be- 
cause the  digestive  globules  and  other  particles  of  food  are  constantly  under- 
going circulation  roimd  the  wliole  of  its  interior.  In  Vorticella,  particles  of 
food  may  occasionally  be  seen  to  circulate  throughout,  and  accumulate  in 
every  comer  of  its  interior,  particularly  those  which  do  not  happen  to  be  en- 
closed in  globules.  Moreover,  the  intimate  resemblance  which  exists  between 
the  alimentary  organs  of  higher  Infusoria  (viz.  Nassula,  Otostoma,  &c.)  and 
those  of  the  binocular  and  so -called  blind  Plaiiarice — in  the  distance  of  the 
mouth  from  the  anterior  extremity,  the  presence  of  a  buccal  apparatus,  and  a 
simple  sac -like  stomach  in  the  latter,  lined  with  a  layer  of  mucous  substance 
(sarcode  ?),  charged  with  the  ^  spherical  cells  '  about  to  be  described — is  so 
great,  that,  with  such  a  simple  gastric  organ  in  an  animal  so  closely  allied  to 
these  Infusoria  as  Planaria,  I  do  not  see  what  reason  we  have,  in  descending 
the  scale,  to  expect  a  more  complicated  digestive  apparatus,  but,  on  the  con- 
trary, one  still  more  simple,  in  which  there  would  be  no  stomach  at  all, — a 
condition  which  appears  to  me  to  be  common  to  all  the  Infusoria  that  have 
come  under  my  notice." 

The  results  of  actual  observation  show  that  food  is  drawn  into  the  mouth 
by  the  action  of  its  siuTOunding  cilia,  and  is  thence  transmitted  rapidly  through 
the  pharynx  and  its  continuation,  the  digestive  tube,  into  the  loose  tissue  of 
the  interior,  assuming  at  first  an  elongated  oval  shape,  but  which  soon  changes 
to  globular  in  its  passage.  The  food  so  introduced  appears  mostly  like  a 
minute  drop  of  water  holding  some  solid  particles  in  suspension,  and  presents 
a  clear  areola  around  a  darker  centre.  Its  course  in  the  interior  seems  to 
depend  on  the  varying  force  of  projection  exerted  by  the  contractility  of  the 


OF  THE  PEOTOZOA. CILIATA.  305 

tube  behind  it  and  by  the  primary  impetus  given  it  by  the  action  of  the  cilia  ; 
thus,  the  more  rapidly  it  is  propelled,  the  greater  is  the  cii'cuit  it  describes. 
Stein  represents  it  to  make  a  wide  spiral  cui've  of  one  or  two  gyrations  in 
Opercularia,  and  in  0.  herherina  to  escape  finally  by  a  determinate  discharg- 
ing orifice  situated  at  the  bottom  of  the  vestibule.  In  this  latter  species,  he 
moreover  describes  the  impetus  of  the  swallowed  portion  to  be  so  strong  as 
to  drive  the  nucleus  from  its  usual  position.  Although  a  discharging  orifice 
in  a  particular  site  is  thus  refen^ed  to  by  Stein  in  the  Opercularia  herherina, 
yet  at  another  page  (p.  17)  he  says,  generally,  that  he  has  been  unable  to  de- 
tect such  a  fixed  vent  in  any  animalcule,  but  that  where  the  excreted  matters 
do  not,  as  in  Chilodon  and  other  species,  escape  by  the  mouth,  they  make 
their  way  to  one  particular  region  of  the  body,  through  which  they  escape, 
not  by  an  opening  with  a  visible  margin,  but  through  a  rupture  of  the  in- 
tegument, which  closes  up  and  disappears  immediately  after  their  exit. 

This  production  of  a  fortuitous  opening  for  the  escape  of  the  excreta,  had 
been  previously  described  by  Dujardin  as  general  in  the  Ciliata,  Siebold,  on 
the  contrary,  upheld  the  opposite  opinion  of  the  existence  of  a  defined  anal 
aperture  among  them.  In  most  Stomatoda,  the  anus  (he  writes)  is  generally 
situated  at  the  opposite  extremity  of  the  body  to  the  mouth,  and  on  the  imder 
surface ;  but  where  it  is  absent,  the  mouth  serves  both  as  inlet  and  outlet,  as 
among  the  Polypes.  Cohn  admits,  at  least  in  certain  cases,  the  presence  of  a 
definite  anus  ;  for  in  his  recent  figures  of  Nassida  elegans  {Zeitschr.,  1858) 
he  indicates  such  an  aperture  (XXYIII.  11^).  Lachmann  is  very  positive 
on  this  question.  He  states  {op.  cit.  p.  127)  that  "  a  long  and  careful  ob- 
sei-vation  of  an  individual  will  always  show  that  the  faeces  are  invariably 
thrown  out  at  the  same  part  of  the  body ;  and  in  many  Infusoria  we  may 
frequently  recognize  the  anus  in  the  form  of  a  smaU  pit  on  the  surface  of  the 
animal,  even  for  a  considerable  time  before  and  after  excretion  (this  is  often 
the  case  in  Paramecium  Aurelia,  P.  Bursaria,  and  Stentor).  That  the  faeces 
are  not  forced  through  the  parenchyma  at  any  point  on  the  suiface  of  the 
body,  is  proved  especially  by  the  careful  observation  of  Spirostomum  ambi- 
guum,  and  some  new  animals  which  are  to  be  united  with  the  Stentors  in  one 
family.  In  the  former,  the  anus  is  situated  at  the  hinder  end  of  the  animal ; 
and  close  in  front  of  it  is  the  very  large  contractile  vesicle.  When  fully  ex- 
panded, this  vesicle  appears  to  be  sun-ounded  only  by  a  thin  membrane  ;  but 
nevertheless  we  see  baUs  of  excrement,  often  several  at  the  same  time,  on 
different  sides  of  the  vesicle,  separating  the  laminae  of  its  apparently  simple 
covering,  and  forming  projections  which  are  often  nearly  hemispherical  both 
towards  the  vesicle  and  the  outer  surface  of  the  body.  If  masses  of  excre- 
ment do  usually  penetrate  through  the  parenchyma  of  the  body,  we  should 
expect  it  to  be  the  case  here  when  the  tension  of  this  is  so  great ;  we  should 
also  expect  to  see  the  masses  of  excrement  pass  into  the  contractile  space,  if 
it  were  not  a  vesicle  but  only  a  space  in  the  parenchyma  without  proper 
walls.  Xeither  of  these  things  occurs,  however ;  the  faecal  masses  are  not 
deposited  from  the  body  until  they  have  reached  the  anus  at  the  hinder  ex- 
tremity of  the  body.  A  similar  strong  expansion  of  a  thin  part  of  the  body 
by  faecal  masses,  without  any  rupture,  is  seen,  as  already  mentioned,  in  some 
new  Stentorina,  which  are  distinguished  from  the  genus  Stentor  by  their 
having  that  part  of  the  parenchjTna  of  the  body  which  bears  the  ciliarj' 
spiral  and  the  aniLs  (which  in  aU  the  Stentorina  lies  on  the  dorsal  siuface  of 
the  body  close  under  the  eihary  spiral,  and  not  in  a  common  pit  vdiYi  a  mouth) 
drawn  out  into  a  thin  process.  In  one  genus,  of  which  I  observed  two  species 
(one  is  the  VorticeUina  ampidla  of  0.  P.  Miiller)  in  company  with  E.  Clapa- 
rede  on  the  Norwegian  coast,  and  which  I  will  describe  elsewhere,  this  pro- 


306  GENERAL  KISTORY  OF  THE  INFUSORIA. 

cess  is  broad  and  foliaceous,  and  bears  the  rows  of  cilia  on  the  margin,  whilst 
the  anus  is  placed  far  up  on  the  dorsal  suiface  of  a  thin  plate.  In  the  other 
genus,  Chcetosjoira  (Lachmann),  observed  by  me  in  fresh -water  near  Berlin, 
the  process  is  narrow  and  bacillar  ;  the  series  of  ciHa  commences  at  its  free 
extremity,  and  only  forms  a  spiral  when  in  action  by  the  rolhng  up  of  the 
lamina  ;  in  this  genus  also  the  process  bears  the  anus.  In  both,  faecal  masses 
which  are  thicker  than  the  process  in  its  extension,  pass  through  it  to  the 
anus,  without  breaking  through  it,  notwithstanding  the  great  expansion  of 
its  walls. 

*<  Not  unfrequently  several  balls  of  excrement  unite  into  a  large  mass 
before  the  anus,  in  order  to  be  passed  out  together.  When  an  excretion  takes 
place,  the  anus  is  seen  to  open  (but  often  closes  once  more  and  opens  again 
before  the  expulsion  of  the  masses  is  effected),  and  then  the  fsecal  masses  are 
often  expelled  slowly." 

He  further  deseribes  the  situation  of  the  anus  in  Ehrenberg's  Oxytrichina 
and  Eiqylota,  in  Colpodea  with  the  exception  of  the  species  of  Amjphileptus 
and  U^'oleptus,  in  the  Cydidina,  and  in  Glaucoma,  Trachelius,  Chilodon,  and 
Nassula,  to  be  on  the  ventral  surface  near  the  posterior  extremity,  or  at  the 
posterior  extremity  itself.  In  Bursaria  and  Spirostoinimi  it  is  placed  at  the 
posterior  extremity,  as  also  more  commonly  in  Colejps,  Enchelys,  and  Trache- 
locerca.  In  the  Stentorma  it  occiu's  on  the  back  close  beneath  the  series  of 
ciha,  and  in  Chilodon  CucuUidus  it  is  nearly  on  the  right  margin  of  the  body 
near  the  hinder  end.  Among  the  true  Vorticellina  and  Ojphrydina  the  anus 
opens  into  the  vestibule  very  close  to  the  oral  aperture,  a  stout  curved  bristle 
being  placed  between  the  two  (XXIX.  2  e,  i). 

Excepting  on  this  point  of  a  preformed,  constant,  and  definite  discharging 
orifice,  there  is  among  microscopists  an  almost  universal  accord  in  the  pre- 
ceding account  of  the  phenomena  connected  with  the  reception  and  digestion 
of  food.  It  would  be  a  useless  expenditure  of  space  to  insert  even  an 
epitome  of  the  observations  and  arguments  of  only  the  most  eminent  of 
modern  naturalists  who  coincide  with  it ;  it  will  be  sufficient  to  cite  their 
names  and  their  contributions  on  the  subject : — Meyen,  in  Edinh.  Phil.  Journ. 
vol.  xxviii. ;  Dujardin,  Histoire  des  Infusoires,  1841 ;  Siebold,  Anatomie  der 
Wirbellosen  Thieve,  1848  ;  Boek,  Ohen's  Isis,  1848  ;  Wagner,  Zootomie,  sect. 
Infusoria,  1848 ;  Yan  der  Hoeven,  Lehrhuch  der  Zootomie,  1850 ;  Leuckart, 
in  Van  der  Hoeven's  new  edition,  1856;  Stein,  Die  Infusionsthiere,  1854; 
Lachmann,  "On  the  Organization  of  the  Infusoria,'' A.  N.H.  1857,xix. ;  Carter, 
Huxley,  and  Carpenter  ;  indeed,  all  British  authorities,  with  whose  works  we 
are  acquainted,  who  have  written  on  the  subject.  This  is  certainly  a  long 
array  of  authorities  against  Ehrenberg's  theory  of  poly  gastric  organization  ; 
and  almost  the  only  advocate  he  has  found  on  his  side  is  Eckhard,  once  a 
pupil  of  his  own.  This  gentleman  has  published  some  observations  which 
seemed  confii^matory,  but  are  undoubtedly  erroneous  in  several  particulars. 
The  follo^ving  remarks,  bearing  specially  on  the  subject  at  present  under  con- 
sideration, may  be  quoted : — 

He  writes — "  In  such  forms  as  are  not  too  minute,  we  can  distinctly  see 
how  the  nutriment,  artificially  supplied,  constantly  takes  a  definite  course  in 
the  body  :  in  some  instances  the  first  portion  of  the  ahmentaiy  tube  can, 
when  not  in  action,  be  observed,  as  in  Epistylis  grandis  ;  it  is  then  frequently 
seen  to  be  covered  on  the  inner  surface  A^dth  cilia,  which,  in  the  Opercularia, 
may  even  be  counted.  But  that  this  alimentary  canal  does  not,  after  a  short 
course,  terminate  abruptly  in  the  body,  can  also  be  proved  in  the  Epistylis 
grandis. 

**  In  this  animalcule  a  portion  of  colouring-matter  swallowed  is  seen  to 


OF  THE  PEOTOZOA. CTLIATA.  307 

course  along  an  intestine  and  enter  a  cell.  I  also  once  attentively  observed 
what  appeared  to  be  the  extremity  of  the  intestinal  canal,  to  ascertain  what 
the  fui'ther  coui'se  of  the  coloured  particles  would  be.  At  this  time  the  animal 
had  not  filled  any  of  the  cells  in  its  inside  ;  suddenly  two  lateral  cells  became 
filled,  although  I  did  not  perceive  any  nutriment  pass  along  the  common  tube. 
This  clearly  points  out  that  the  two  cells  must  be  in  connexion  with  the  com- 
mon cavity  from  which  they  had  become  filled ;  and  when,  after  the  animal 
has  fed  for  a  considerable  time,  we  see  that  similar  filled  cells  are  diff'used 
throughout  the  body,  this  phenomenon  aff'ords  a  ground  for  the  supposition 
that  the  intestinal  cavity  is  of  greater  length  than  we  should  at  first  sight 
imagine."  (Wiegmann's  Archiv,  1846,  translated  in  A.  N.  H.  1847,  xviii. 
p.  433.) 

M.  Pouchet,  of  Eouen  (Comptes  Renclus,  xxviii.  pp.  82-516),  has  also 
adopted  Ehrenberg's  notion  of  definite  gastric  cells,  but  has  been  unable  to 
convince  himself  of  the  connecting  intestine.  Mr.  Samuelson  also  (J.  M.  S. 
1856,  p.  165  ;  1857,  p.  104)  seems  to  coincide  with  this  view;  but  in  his  se- 
veral papers  on  Glaucoma,  cited,  there  occur  variations  in  description,  which 
very  much  detract  from  their  weight  in  deciding  on  any  disputed  point. 

Lachmann  gives  the  follo^ving  details  (A.  JSf.  H.  xix.  p.  118)  : — "  The  vesti- 
bulum  continues  the  spiral  line  formed  by  the  row  of  ciHa,  constituting  a  bent 
tube,  which  contains  a  portion  of  this  spire  of  cilia.  In  accordance  with  the 
direction  of  this  spiral,  the  concavity  of  the  tube  is  turned  towards  the  right, 
and  its  convexity  towards  the  left :  on  the  convex  side  the  lumen  of  the  tube 
is  still  more  enlarged,  especially  in  the  parts  placed  furthest  inwards,  where 
the  anus  opens.  Between  the  anus  and  the  mouth  which  leads  further  in- 
wards into  the  oesophagus  springs  a  bent  bristle,  which  is  generally  long 
enough  to  project  outwards  beyond  the  peristome.  This  bristle  is  stiif,  and 
is  only  displaced  a  little  to  one  side  occasionally,  when  balls  of  excrement, 
which  are  too  thick  to  pass  between  it  and  the  wall  of  the  vestibulum,  are 
thrown  out  from  the  anus ;  but  it  immediately  returns  again  to  its  old  ^Josition. 

"  From  the  mouth  a  short  tube,  the  oesophagus,  with  a  far  smaller  lumen 
than  the  vestibulum,  leads  to  a  rather  wider  fusiform  portion,  which  we  wiU 
call  the  phaiyn^v.'' 

This  selection  of  terms  we  consider  unfortunate,  because  it  is  opposed  to 
their  customary  usage  in  comparative  anatomy, — the  pharjux  being  always 
said  to  be  prolonged  into  the  oesophagus,  and  not  the  latter  into  the  former. 
In  aU  the  Ciliata,  except  the  Vorticellina,  the  canal  continuing  from  the  oral 
apertui^e  is  not  distinguishable  into  two  portions  or  segments  ;  and  one  terra 
would  suffice  to  designate  it  throughout.  In  that  class,  where  a  division  may 
possibly  be  remarked,  it  would  be  better  to  call  the  upper  segment  the  pharynx 
or  oesophagus,  and  the  lower  the  alimentary  tube  ;  by  so  doing,  no  false  con- 
ceptions could  weU  arise.  However,  in  quoting  from  Lachmann's  description 
we  must  let  the  words  abide  with  the  meaning  he  has  assigned  them. 

To  continue  our  extract — "  In  most  Vorticellina  (those  with  a  contractile 
stem,  and  the  species  of  Epistylis  and  Trichoclina)  the  longitudinal  axis  of 
the  vestibulum  and  oesophagus  runs  tolerably  parallel  to  the  plane  of  the  ciliary 
disk,  whilst  that  of  the  pharynx  has  rather  the  direction  of  the  axis  of  the  body. 
In  these,  therefore,  the  axis  of  the  ciliary  spiral,  which  is  continued  as  far  as 
the  pharynx,  changes  its  direction  at  the  commencement  of  the  vestibulum  : 
whilst  it  coincided  vdih.  the  axis  of  the  body  outside  the  vestibulum,  it  stands 
almost  perpendicular  to  it  within  the  vestibulum  and  in  the  oesophagus.  In 
the  very  elongated  forms  of  the  Ophrydina  (Ehr.),  which  inhabit  sheaths 
(Ophrydium,  Vaginicola,  Cothurnia),  the  longitudinal  axis  of  the  vestibulum 
and  oesophagus  coincides  more  with  that  of  the  body,  as  also  in  the  genera 

X  2 


308  GENERAL  HISTORY  OF  THE  INFUSORIA. 

Opercularia  (as  circumscribed  by  Stein)  and  Lagenophrys,  Stein ;  in  tlie  two 
latter  the  vestibulum  is  very  wide,  whilst  in  the  elongated  species  it  is  narrow, 
but  generally  possesses  a  deep  excavation  for  the  anus." 

''  Besides  the  cilia  of  the  spiral  (cihary  wreath),  some  stronger  cilia  also 
stand  in  the  vestibulum,  in  front  of  the  mouth ;  these  do  not  take  part  in 
the  regular  activity  of  the  others,  but  only  strike  forcibly  sometimes, — appa- 
rently to  remove  from  the  vestibulum  coarse  substances  which  may  have  got 
into  it,  and  also  the  masses  of  excrement." 

"  The  morsel  passed  from  the  pharynx  into  the  interior  of  the  body  runs 
nearly  to  the  posterior  extremity  of  the  Vorticella,  and  then,  turning  upwards, 
rises  on  the  side  of  the  body  opposite  to  the  pharynx.  Duiing  this  portion 
of  its  course,  it  usually  still  retains  the  spindle-shape  communicated  to  it  by 
the  pharynx,  and  only  here  changes  to  the  globular  form,  often  rather  sud- 
denly :  this  induced  me  at  first  to  think  that  the  morsel  was  still  enclosed  in 
a  tube  during  this  part  of  its  course  ;  and  this  opinion  seemed  to  be  supported 
by  the  cii'cumstance  that,  before  and  behind  the  morsel,  two  lines  are  not  un- 
frequentiy  seen,  which  unite  at  a  short  distance  from  it,  like  the  outlines  of 
a  tube  which  it  has  dilated.  Subsequent  observations,  how^ever,  have  again 
sho^Ti  me  that  this  opinion  is  an  improbable  one  ;  for  the  circumstances  de- 
scribed must  also  occur  when  a  fusiform  morsel  is  passed  wdth  some  force  and 
rapidity  through  a  quiescent  or  slow-moving  tenacious  fiuid  mass  :  the  above- 
mentioned  lines,  before  and  behind  the  morsel,  must  be  produced  by  the  se- 
paration and  reunion  of  the  gelatinous  mass,  even  if  the  morsel  is  not  sur- 
romided  by  a  tube.  But  the  existence  of  a  tube  depending  from  the  pharynx 
appears  also  to  be  directly  contradicted  by  the  fact,  on  the  one  hand,  that  the 
curves  described  by  the  morsel  are  sometimes  larger  and  sometimes  smaller, 
and  on  the  other,  that  the  morsel  acquires  the  globular  form  sometimes  sooner 
and  sometimes  later,  according  as  it  is  pushed  out  of  the  j^harynx  with  greater 
or  less  force  and  rapidity.  The  masses  v*^liirled  into  the  pharynx  are  not 
always  aggregated  into  a  morsel ;  but  sometimes,  under  conditions  which 
have  not  yet  been  satisfactorily  ascertained,  all  the  masses  which  reach  the 
pharynx  are  seen  to  pass  quickly  through  it  without  staying  in  it ;  they  then 
stream  through  the  mass  surrounding  them  in  a  clear  streak  which,  like  the 
morsels,  describes  a  curve  at  the  bottom-  of  the  bell,  and  only  mix  with  the 
mass  when  their  rapidity  of  motion  has  diminished.  A  roundish  morsel,  which 
might  be  regarded  as  a  fiill  stomach,  is  then  never  formed.  We  might  easily 
be  inclined  to  regard  the  clear  bent  streak  wdth  the  particles  flowing  in  it  as 
an  intestine ;  and  this  has  probably  been  done  by  Ehrenberg,  who  states  that 
he  distinctly  saw  the  bent  intestine  in  some  VorticeUina,  especially  in  Epi- 
stylis  plicatilis,  in  which  I  have  also  been  able  to  study  the  phenomenon  very 
closely.  But  in  this  case  also  there  are  the  same  reasons  against  the  sup- 
position of  an  intestinal  tube,  as  in  that  of  the  lines  appearing  before  and 
behind  a  fusiform  mass  :  here  likewise,  not  only  the  form,  but  also  the  length, 
of  the  curve  varies :  whilst  at  one  time  it  is  but  short,  and  soon  terminates 
by  the  intermixtiu"e  of  the  particles  contained  in  it  with  the  suiTounding 
mass,  it  may  immediately  afterwards  be  twice  as  long  or  longer — it  may  even 
make  a  complete  circuit  and  return  nearly  to  its  point  of  commencement  be- 
neath the  pharynx- — a  variation  which  appears  only  to  depend  upon  the  force 
with  w^hich  the  cilia  of  the  rotatory  organ  act ;  so  that  we  cannot  explain  the 
W' hole  phenomenon  otherwise  than  that  the  water  with  the  particles  contained 
in  it,  streaming  with  some  rapidity  into  the  mass  w^ith  which  the  body  is 
filled,  cannot  mix  with  the  latter  immediately,  but  only  when  its  rapidity  of 
motion  is  diminished  by  friction, — -just  as  we  see  a  rapid  stream  which  falls 
into  a  sluggish  or  stagnant  pool,  or  into  the  sea,  still  retaining  its  independ- 


OF  THE  PROTOZOA. CILIATA.  309 

ence  for  a  certain  space,  so  that,  if  it  differs  in  its  colour  or  turbidity  from  the 
water  of  the  sea  or  pool,  we  may  distinguish  it  from  the  latter  (with  which 
it  does  not  mix  for  a  long  time)  in  the  form  of  a  streak,  w^hich  is  often  of 
great  length. 

*'  ^\Tien  the  nutritive  particles  in  the  body  of  the  Vorticellce  have  attained 
the  end  of  the  clear  streak  under  a  constant  diminution  of  theii'  rapidity — and 
in  the  other  case,  when  the  morsel  has  lost  its  spindle-shape  and  become  glo- 
bular— they  have  no  longer  any  separate  movement,  but  now  only  take  part 
in  a  circulatory  motion,  in  which  all  the  parts  in  the  interior  of  the  body, 
with  the  exception  of  the  nucleus  and  contractile  vesicle,  are  engaged." 

This  account  applies  in  general  to  the  alimentary  mechanism  of  all  other 
Ciliata  besides  the  VorticelUna,  except  so  far  as  concerns  the  dilated  lower 
half  of  the  oesophagus  (/.  e.  pharynx  of  Lachmann),  which  is  never  seen. 
The  cihated  oesophagus  ends  by  an  obliquely  truncate  extremity,  through 
which  the  di^ap  of  water  introduced  by  the  mouth  enters  the  tenacious  fluid 
mass  of  the  interior,  where  it  expands  into  a  rounded  vacuole  or  stomach-sac, 
which  continues  its  onward  ciu-vilinear  course  until,  by  absorption  or  by  ex- 
pulsion thi'ough  the  anal  outlet,  it  disappears.  Yet  it  may  happen,  just  as  in 
the  VorticeWma,  that  the  water  and  food,  instead  of,  as  usual,  being  united 
into  di'ops  and  morsels,  may  be  mixed  at  once  with  the  contents  of  the  abdo- 
men, and  no  semblance  of  a  fuU  vacuole  be  produced. 

A  remarkable  fact  is  recorded  by  Lachmann,  of  the  digestive  organization 
of  Trachelius  Ovuin,  in  which,  by  the  way,  Ehrenberg  declared  the  alimentary 
canal  was  more  easily  seen  than  in  any  other  animalcule.  "  In  Trachelius 
Ovum/'  writes  the  author  we  quote  (p.  127),  "  alone  we  see  a  proper  stomach- 
wall  separated  from  the  rest  of  the  parenchyma  by  spaces  filled  ^\dth  fluid, 
and  thus  form  an  arborescent  ramified  canal,  which,  however,  must  not  be 
confounded  with  the  nucleus."  To  this  statement  he  adds,  in  a  foot-note, 
— "  The  animalcules  devoured  (Trachelius  Ovum  is  one  of  the  most  voracious 
robbere)  are  always  seen  lying  in  the  ramifications  of  the  stomach,  in  the  clear 
spaces  between  them,  except  in  crushed  animals.  The  clear  round  spaces  in 
the  parenchyma  (cortical  lamina)  of  the  body,  are  certainly  no  stomachs,  but 
contractile  spaces."  This  structure  was  affirmed  to  the  wi'iter  by  Lieberkiihn, 
and  was,  no  doubt,  seen  by  Ehrenberg,  but  misunderstood  by  him  in  most 
points.  Its  gastric  character,  however,  has  not  past  unchallenged,  for  both 
Cohn  and  Leuckhart  (AYiegmann's  Archiv,  Bericht,  1855)  assert  that  it  is  no- 
thing more  than  a  fibrous  band  extending  inwards  from  the  integument  in 
difl'erent  directions  through  the  soft  contents  of  the  interior.  In  this  expla- 
nation Gegenbauer  seems  to  agree — the  granular  bands  described  by  this 
observer  under  the  name  of  ''  trabecuUe  "  appearing  identical  with  the  fibres 
of  the  two  last-named  writers.  These  trabeculce  are  stated  to  be  contractile 
and  to  have  a  definite  arrangement,  the  principal  one  extending  backwards 
from  the  long,  ciliated,  oral  fissure  along  the  same  side  of  the  body,  and  ha^dng 
secondary  trabeculae  branching  from  it  and  proceeding  to  the  cortical  lamina, 
where  they  are  lost.  And  although  Gegenbauer  speaks  of  an  intestine-like 
structure  prolonged  backwards  from  the  mouth,  in  which  numerous  food- 
globules  could  be  seen,  yet  he  says  that  there  was  no  perceptible  difference 
in  structure  to  distinguish  this  so-caUed  intestine  from  the  rest  of  the  body. 
Moreover  he  notes  that  the  nutritive  globules  may  be  often  seen  passing 
through  the  smaller  trabeculae.  Besides  the  oral  fissiu'e,  he  remarked  another 
opening  situated  further  forward  than  it,  beneath  the  motile  proboscis,  Avhere 
the  tegumentary  wall  is  thick,  and  connected  with  a  trabecula  extending 
inwards  to  unite  with  others.  This  opening  he  found  to  be  constant  in  size 
and  position,  to  be  prolonged  inwards  to   the  chief  trabecula    as   a  wide 


310  GENEEAL  HISTOKY  OF  THE  INFUSORIA , 

fiiniiel- shaped  tube,  often  delicately  plaited  longitudinally,  and  suiTounded 
■with  cilia.  Ai'titicial  feeding  was  tried ;  but  no  colouring  particles  were  swal- 
lowed. The  existence  of  a  digestive  power  is  sho^syn  by  the  disappearance  of 
organic  matters  which  have  been  swallowed,  leaving  little  or  no  residue  un- 
absorbed.  Thus  other  smaller  animal  organisms  are  often  the  prey  of  Ciliata  ; 
and  their  gradual  absorption  into  the  general  mass  may  be  occasionally 
watched  :  the  same,  too,  is  true  of  vegetable  matters  such  as  Diatomece,  Des- 
midiece,  portions  of  Oscillatorice,  and  of  various  minute  Algae, — although  here 
a  certain  amount  of  miassimilated  matter  in  the  hard  lorica  or  valves  remains 
over  and  above,  to  be  subsequently  got  rid  of.  The  changes  ensuing  in  food 
during  the  act  of  digestion  are  illustrated  by  Ehrenberg  in  his  account  of 
Bursaria  vernalis.  This  animalcule  feeds  very  much  on  OsciUatorice  ;  and  on 
watching  the  fibres,  they  are  seen,  when  first  swallowed,  to  be  elastic,  rigid, 
and  of  a  beautiful  bluish-green  colour,  but  presently  they  become  lax  and 
of  a  bright  green  hue,  which  afterwards  changes  to  a  yellowish  green,  and 
ultimately  to  a  yellow,  the  filaments  at  the  same  time  breaking  up  into  de- 
tached joints. 

An  assimilative  function  is  evidenced  both  by  the  foregoing  facts  of  the 
absorption  of  foreign  organized  matters,  and  also  by  the  circumstances,  that 
the  magnitude  acquired  and  the  activity  of  other  functions  are  regulated  by 
the  quantity  of  nutriment  received,  and  that  after  certain  substances  have 
been  taken  as  food  they  may  be  detected  in  certain  parts,  or  thi'oughout  the 
tissue  of  the  animalcule.  Of  the  latter,  the  introduction  of  chlorophyll  into 
the  subtegumentary  tissue,  by  the  medium  of  food  containing  this  vegetable 
constituent,  is  an  example ;  and  in  general  the  colom^  of  an  animalcule  depends 
directly  on  the  food  taken,  or  is  indirectly  influenced  by  its  quality  and 
quantity ;  for  an  animal  well  nourished  always  exhibits  its  pecuHar  colour 
in  the  highest  degree,  whilst  ill-nouiished  sickly  examples  present  little  or 
none. 

This  topic  suggests  another  closely  allied  to  it,  viz.  the  artificial  feeding 
with  coloured  substances,  so  much  resorted  to  by  Ehrenberg  in  his  researches. 
It  consists  in  the  introduction  of  a  very  small  quantity  of  some  insoluble 
coloiu',  not  a  poison,  capable  of  minute  division,  into  the  water  in  which  the 
animal  floats  whilst  under  observation.  The  colours  generally  employed  are 
indigo  and  carmine,  a  Httle  of  one  or  other  of  which  is  rubbed  on  the  wet 
margin  of  the  slide,  sui^rounding  the  thin  glass  cover,  whence  it  gradually 
steals  under  the  cover,  and  disperses  its  flne  particles  through  the  little  drop 
in  which  the  animalcule  floats. 

Another  substance  has  been  proposed  as  preferable,  by  Mr.  Thomas  A\Tiite 
(J.  M.  S.  1854,  p.  282),  viz.  the  red  eyes  of  the  common  fly,  reduced  to  fine 
powder  by  pressm^e.  By  feeding  animalcules  with  this  in  heu  of  carmine,  the 
disadvantage  aiising  fi'om  the  dark  particles  of  the  latter  crowding  the  field  of 
view  and  obscuring  the  objects  is  obviated  ;  and,  on  the  other  hand,  it  has  the 
actual  advantage  of  being  more  readily  imbibed,  and  therefore  of  appealing 
more  speedily  in  the  apparent  stomach-sacs. 

Ehrenberg  imagined  that  the  Cihata  enjoy  the  sense  of  taste,  leading  them 
to  choose  or  refuse  at  ^vill  among  articles  of  nourishment  within  theii*  reach. 
Thus  he  says  that,  amidst  a  number  of  inchviduals  of  Paramecium  Aurelia, 
some  took  one  sort  of  food,  and  others  another, — no  doubt  a  correct  observa- 
tion, but  insufficient  to  prove  the  existence  of  taste.  Nevertheless  it  must  be 
allowed  that  some  animalcules  are  especially  found  in  company  either  with 
certain  other  small  animal  organisms,  or  with  particular  plants,  or  in  water 
holding  certain  matters  in  solution, — a  fact  upon  which  our  knowledge  con- 
cerning their  habitats  and  modes  of  life  rests,  but  in  itself  no  proof  of  the 


or  THE  PROTOZOA. CTLIATA.  311 

existence  of  a  sense  of  taste.  Indeed,  in  the  case  of  minute  plants  we  per- 
ceive a  similar  apparent  selection  of  localities  abounding  in  appropriate  nutritive 
matters.  Another  assumed  vital  characteristic  was,  that  Cihated  Infusoria 
have  a  feeling  of  company  (a  fondness  for  society),  inducing  them  to  con- 
gregate together, — an  idea  requiring  considerable  effort  of  imagination  to 
conceive,  but  which,  we  fear,  -will  scarcely  find  acceptance  as  a  fact  by  any 
person  who  will  look  abroad  for  parallel  instances  of  the  congregating  together 
of  the  same  organisms  ;  and  plenty  such  are  at  hand,  even  among  the  lowest 
plants. 

Dextal  AppAEATrs,  OR  Teeth. — Before  quitting  the  subject  of  digestion  and 
of  the  digestive  organs,  some  notice  must  be  taken  of  the  pecuHar  formations 
considered  by  Ehrenberg  to  represent  a  dental  apparatus  concerned  in  the 
preparation  of  the  food  for  digestion.  This  apparatiLS  occurs  in  the  form  of 
a  cyhnder  of  apparent  bristles  (XXIV.  282,  2m,  308,  309 ;  XXIX.  48)— 
the  supposed  teeth — placed  behind  the  mouth,  as  seen  in  Ohilodon  (XXIX. 
48),  Nassida,  Chlamidodon,  and  Prorodon  (XXVIII.  8,  65).  The  cylinder 
of  teeth  was  fm^ther  stated  to  be  wider  in  fi'ont,  to  be  able  to  expand  itself  to 
receive,  and  afterwards  to  contract  on  the  engulfed  particle  of  food,  so  as  to 
crush  it  and  drive  it  inwards. 

To  these  notions  of  the  natui-e  and  action  of  the  organ  in  question,  Stein 
cannot  assent.  He  states  (p.  128)  that  he  has  frequently  tried  in  vain  to 
isolate  it.  On  killing  an  animalcule  with  solution  of  iodine,  or  with  dilute 
acetic  acid,  the  funnel-like  tube,  at  times  straight,  at  others  ciu^ved,  is  di- 
stinctly displayed,  as  well  in  the  smallest  as  in  the  larger  specimens.  It 
tapers  posteriorly,  and  ends  abruptly  by  an  open  extremity  in  the  ca\dty, 
and  is  composed  of  the  same  resistant  elastic  membrane  as  the  cuticle. 
Stein  gives  it  the  name  of  the  '•'  oesophageal  funnel."  Its  wider  and  thicker  end 
is  truncate  and  dentate  or  serrate,  having  from  8  to  16  dentations  :  between 
these  the  membrane  appears  to  be  plaited  or  groved  for  a  considerable  distance 
do^vnwards ;  and  it  is  these  plaits  or  folds  which  Ehrenberg  took  to  be  long 
bristle-like  teeth  arranged  side  by  side.  This  cylinder,  therefore,  is  nothing 
more  than  an  involution  of  the  integument.  It  can  be  retracted  and  appear 
like  a  tapering  oesophageal  tube,  or  be  protruded  like  a  tinimpet- shaped  pro- 
cess beyond  the  general  surface.  It  has  not,  however,  that  independent 
motile  power  in  itself  represented  by  Ehrenberg ;  but  all  its  movements 
depend  upon  those  of  the  integument ;  for  Stein  has  never  seen  it  either  con- 
tract or  dilate,  except  simultaneously  with  the  contractions  of  the  general 
surface.  It  bends,  and  is  doubled  up  under  pressure,  and  is  neither  denser 
nor  a  more  brittle  tissue  than  the  cuticle  ;  nor  can  it  be  resolved  into  rod-like 
segments. 

The  plaited  upper  portion  is  not  apparent  in  all  species  which  have  a 
homologous  organ:  thus  mNassula  ambigua  (Stein,  ]).  249)  the  infundibulum 
is  smooth,  although  the  double  outhne  its  membrane  exhibits  indicates  its 
very  considerable  thickness. 

Secretion. — Sufficient  e\4dence  of  the  operation  of  this  function  is  found 
in  the  Ciliated  Protozoa,  although  no  special  organs  or  tissues  can  be  pointed 
out  for  its  exercise,  unless,  indeed,  the  paii'  of  peculiar  solid-looking  organs 
in  the  head  of  Opercidaria  berberiformis,  hereafter  mentioned  among  accessory 
undetermined  structures,  be  considered  glandular  (XXX.  2  c). 

The  production  of  cilia  may  be  considered  an  act  of  secretion,  exercised  so 
soon  as  an  animalcule  assumes  a  definite  outline,  and,  imder  certain  circum- 
stances in  connexion  with  the  encysting-process,  repeated  a  second  time 
within  the  life-time  of  an  individual.  Again,  the  excretion  thrown  out 
around  Protozoa  when  about  to  encyst  them^^elves  is  another  example  of  the 


312  GENERAL  HISTOEY  OF  THE  INFUSORIA. 

same  process  ;  so  is  also  the  special  production  of  cuticular  matter  in  the  con- 
struction of  the  dense  resisting  shields  and  urceoL*  of  loricated  species,  e.  g. 
Coleps,  or  that  of  the  substance  used  in  the  formation  of  stems  and  of 
external  sheaths.  Another  instance  of  a  secretion  maybe  seen  in  the  solvent 
fluid  poured  out  for  the  solution  of  solid  particles  of  food  in  the  interior, — a 
fluid  certainly  not  demonstrable  apart,  but  presumable  from  the  phenomena 
of  digestion. 

Having  observed  the  particles  of  food  in  the  abdominal  cavity  to  be  fre- 
quently surrounded  by  a  clear  space  filled  mostly  with  colourless,  but  some- 
times ^vith  a  coloured  liquid,  Ehrenberg  at  once  attributed  to  it  a  digestive 
faculty,  and  termed  it  the  bile.  He  speaks  of  this  in  the  history  of  the  genus 
Bursaria,  where  it  is  stated  to  be  either  coloiuiess  or  reddish.  In  Nassula, 
again,  lie  figures  biliaiy  glands  in  the  shape  of  vesicles  forming  a  mde  circlet 
around  the  mouth,  filled  with  a  violet- coloured  juice,  which  is  discharged 
with  the  excrementitious  particles,  and  which  at  first  appears  like  di'ops  of 
oil,  but  soon  mixes  with  and  becomes  diffused  through  the  water.  The 
following  species  are  enumerated  as  possessing  one  such  vesicular  gland :  viz. 
Chilodon  ornatus,  Bursaria  vernalis,  Traclielius  Meleagris,  AmpliUeptus  7iuir- 
garitifer,  A.  Meleagris,  and  A.  hngicollis. 

The  bodies  thus  represented  by  Ehrenberg  as  vesicular  glands  have  not 
escaped  the  notice  of  Stein,  who  pronoimces  distinctly  against  their  glandular 
natui'e,  and  insists  upon  theii'  being  nothing  but  sections  or  joints  of  the  fibres 
of  the  Oscillatorice  and  other  plants  that  the  animalcules  feed  upon,  and  which, 
in  the  course  of  their  digestion,  change  from  green  to  a  dusky  blue,  afterwards 
to  a  reddish-brown  colour,  and  at  length,  when  broken  up,  become  difiiised 
throughout  the  interior,  and  impart  to  the  entii^e  animalcule  a  reddish- 
yellow  hue. 

Cohn  {Zeitschr.  1857,  p.  143)  has  remarked  in  Nassula  elegans  numerous 
granules  of  a  yellowish -brown  and  violet  colour,  either  collected  into  heaps 
or  scattered  through  the  interior.  On  the  under  smface,  near  the  anus,  is 
usually  a  large  violet  mass,  and  at  the  opposite  extremity  a  similar  smaller 
one,  which  have  been  described  by  Ehi^enberg  as  biliary  glands  (XXYIII.  11, 
12).  If  they  are  not  particles  of  vegetable -coloured  food  altered  in  hue  by 
the  process  of  digestion  or  solution,  they  may,  says  Cohn,  be  considered 
analogous  to  the  chlorophyll-corpuscles  of  Paramecium  (Loxodes)  Bursaria, 
of  Sjpirostomum,  or  of  Vorticella  viridis,  and  a  special  form  of  colouring 
matter.  The  collection  of  the  coloured  mass  about  the  anus,  and  its  dis- 
charge in  the  shape  of  bluish  particles — facts  noticed  by  Ehrenberg — indicate 
its  nature  to  be  effete  and  excrementitious.  Yet  it  is  not  the  mere  crude 
joints  of  OsciUatoria,  as  Stein  supposed,  but  matter  which  has  been  digested. 
The  heap  about  the  neck  is  by  no  means  constant. 

Contractile  Yesicle. — Passing  now  to  the  other  contents  of  the  Ciliata, 
the  contractile  vesicle  or  space  first  arrests  our  attention.  Mr.  Carter  would 
call  it  simply  the  '  vesicula  ;  '  but  this  word,  without  the  adjunct  "  contractile  " 
to  particularize  it,  seems  insufficient,  especially  when  the  Latin  language  is 
used  in  description. 

This  organ  is  of  universal  occurrence  among  the  Ciliata  ;  it  is  mostly  single  ; 
but  in  a  few  instances  two  and  even  three  such,  mostly  of  unequal  magnitude, 
occur.  It  did  not  escape  the  notice  of  Ehrenberg,  who  has  figured  it  in  all 
his  plates  of  these  beings.  It  occurs  as  a  clear,  hoUow,  mostly  roimded  space 
in  the  interior,  its  precise  position  differing  in  different  species.  It  is  always 
placed  in,  or  closely  connected  with,  the  cortical  or  contractile  lamina,  and  is 
not  affected  by  the  circulatory  current.  In  the  great  majority  of  species  it 
is  situated  nearer  the  anterior  extremitv,  and  in  verv  close  relation  with  the 


OF  THE  PROTOZOA. CILIATA.  313 

mouth  or  alimentary  tube :  thus  in  Ophryoglena,  Bursa ria,  Opercularia, 
Epistylis,  and  Zoothamnium  it  lies  close  upon  the  vestibulum  within,  or 
almost  within,  the  region  of  the  ciliary  wreath  (XXVII.  16;  XXX.  9-11)  ; 
in  Vorticella  and  Vaginicola  it  is  placed  against  the  upper  part  of  the  ali- 
mentary tube,  and  in  Tncliodina,  Nassula,  and  many  others,  near  it  at  its 
termination  (XXX.  5,  6,  17;  XXIX.  4).  Exceptions  to  this  position  are 
met  ^\iih.  in  Colejps  and  Colpoda  (XXIX.  35-37),  where  it  occupies  the 
posterior  extremity,  placed  very  close  to  the  external  sui^face.  When  two 
vesicles  exist,  they  are  often  placed  on  opposite  sides  of  the  body,  the  one 
more  or  less  anterior  to  the  other,  as  seen  in  Paramecium  (XXIX.  29,  30). 
In  Chilodon  Ciicullidus  a  third  is  sometimes  seen  near  the  posterior  extremity 
(XXIX.  48). 

On  watching  these  clear  spaces,  they  are  observed  to  disappear  for  a  few 
moments  and  again  to  reappear — in  other  words,  to  exhibit  rhythmical  con- 
tractions, a  feature  which  distinguishes  them  from  any  other  vesicular  spaces. 
The  contraction  is  known  as  the  '  systole,^  the  re-expansion  as  the  '  diastole ; ' 
these  movements  may  be  either  regular  or  irregular,  and  they  differ  in  dura- 
tion in  different  species.  Perty  states  that  the  pulsations  in  Stylo7iychia 
pustidata  occupy  from  six  to  seven  seconds  :  in  Spirocliona  and  Colpoda  they 
are  more  prolonged ;  indeed,  as  Stein  affirms,  they  are  slower  in  the  former 
genus  than  in  any  other  animalcule  he  has  examined.  When  more  than  one 
vesicle  is  present,  no  uniformity  in  the  order  of  their  movements  has  hitherto 
been  proved,  although  Siebold  believes  they  must  follow  some  nile.  As  evi- 
dence of  the  independence  of  the  vesicle  of  the  general  contents  of  the  body, 
Lachmann  records  {A.  N.  H.  1857,  xix.  p.  126)  the  fact  that,  even  after  the 
contents  of  an  animalcule  have  been  sucked  out  by  an  Acineta,  the  vesicle 
lodged  in  the  still  present  and  contractile  layer  may  continue  to  pulsate  for 
several  hours. 

With  regard  to  the  number  of  these  vesicles  in  particular  species,  much 
discrepancy  has  existed  among  observers.  Siebold  affirms  that  Ehrenberg  has 
proceeded  in  a  pui-ely  arbitrary  manner  in  calling  one  a  contractile  or  sper- 
matic sac,  and  others,  indistinguishable  from  it,  gastric  cells,  and  quotes  in 
illustration  the  Berlin  Professor's  description  of  the  vesicles  of  Amphileptus 
meUagris  and  of  A.  loyigicollis.  To  this  objection  Eckhard  rejoined  by  assert- 
ing that  Ehrenberg  was  guided  in  detennining  the  natiu^e  of  vesicles  by  cer- 
tain appreciable  differences  in  the  character  and  contractions  of  different  sacs, 
and  that  Siebold  had  erroneously  represented  lateral  abdominal  vesicles  in 
Stentor,  and  an  elongated  one  in  Spirostomum  amhiguum.  In  this,  however, 
he  was  WTong,  for  the  description  of  Siebold  has  been  confii-med  by  Lachmann 
and  others  (XXIX.  7)  ;  and  on  the  other  hand,  Ehrenberg  is  not  so  much  in 
error  respecting  the  numbers  of  these  vesicular  spaces  as  Siebold  was  led  to 
suppose. 

It  is,  indeed,  only  by  careful  and  repeated  observations  that  such  variations 
can  be  reconciled.  In  pronouncing  a  space  contractile,  a  sufficient  criterion 
seems  to  be  found  in  the  cii^cumstance  of  a  like  organ  being  found,  in  aU 
specimens  of  the  same  animalcule,  constant  in  position,  and  rhythmical  in 
its  movements.  Gastric  cavities  or  alimentary  vacuoles  may  collapse  and 
disappear ;  but  this  movement  is  not  followed  by  renewed  acts  of  disappear- 
ance and  reappearance  in  regular  succession,  and  in  the  same  spot ;  for  if  one 
such  vacuole  do  replace  another,  a  general  movement  onwards  in  the  course 
of  the  internal  cyclosis  may  be  discovered.  Another  test  to  distinguish  a 
stomach -vesicle  fi^om  a  true  contractile  sac  may  be  found  in  the  use  of  coloured 
food.  Xow  that  the  special  contractile  sac  is  admitted  generally  to  be  merely 
the  central  organ  of  a  system  of  contractile  vessels  disposed  at  various  parts 


314  GENEEAL  HISTORY  OF  THE  INEUSOEIA, 

of  the  body,  the  appearance  at  times  of  additional  vesicles,  and  consequently 
also  the  discrepancies  of  authors  as  to  the  numbers  present,  are  exphcable 
by  supposing  the  accidental  dilatation  of  a  tube  here  and  there — as  a  vari- 
cose vessel, — the  dilatations  representing  for  the  time  additional  contractile 
spaces. 

This  explanation  occuiTed,  among  others,  to  Mr.  Carter.  Thus  he  remarks 
(A.  N.  H.  1856,  xviii.  p.  128)  that  in  Chilodon,  where  the  vesicle  is  normally 
single  and  near  one  extremity,  it  is  not  imcommon  to  meet,  amid  a  group  of 
these  animalcules,  various  indi\T[duals  presenting  a  variable  number  of  con- 
tractile vesicles  irregularly  dispersed  through  the  body,  without  one  being  m 
the  true  position  of  the  '  vesicula.'  "  That,"  he  writes,  "  the  '  vesicula '  does 
make  its  appearance  now  and  then,  may  be  inferred,  as  it  perhaps  may  also 
be  inferred  that  from  over-irritabihty,  or  some  such  cause,  it  does  not  remain 
under  dilatation  long  enough  to  receive  the  contents  of  the  sinuses ;  and  hence 
their  accidental  dilatation,  and  the  appearance  of  a  plurahty  of  vesiculae." 

To  this  accidental  dilatation  of  vasculai^  channels  at  particular  points  may 
be  referred  the  50  to  60  regularly  placed  vesicles  described  by  Gegenbauer 
in  Trachelius,  the  12  to  16  mentioned  by  Siebold  and  Perty  in  Ampliileptus, 
and  also  the  row  of  them  seen  along  the  side  of  Stentor.  In  this  last-named 
genus  there  is  a  circular  canal  sm-rounding  the  head  or  ciliary  wreath,  which 
sends  off  a  branch  at  right  angles  along  the  side  to  nearly  its  posterior  end 
(XXIX.  7).  In  Sjpirostomum,  again,  a  long  contractile  channel  occuj)ies  the 
length  of  the  body. 

The  existence  of  a  second  vesicle  in  an  animalcule  normally  possessing  but 
one,  Ehrenberg  explained  by  supposing  an  act  of  fission  to  have  occurred 
prior  to  division  of  the  entire  being, — an  explanation  in  which  Mr.  Carter 
concurs.  But  if  Stein  be  right,  the  contractile  vesicle  does  not  undergo 
fission,  but  makes  its  appearance  in  the  newly-formed  half  by  an  act  of 
development  de  novo.     In  this  statement  Wiegmann  concurs  (Perty,  p.  63). 

Ehrenberg  concluded  the  contractile  spaces  to  be  true  sacs,  limited  by  a 
definite  membrane, — a  conclusion  sanctioned  also  by  Siebold,  forasmuch  as, 
during  successive  contractions  and  dilatations,  the  vesicles  retain  the  same 
place,  figure,  and  number.  Mr.  Carter  supphes  direct  evidence  of  the  fact 
{A.  N.  H.  1856,  xviii.  p.  130),  having  obsei-ved  on  one  occasion  a  vesicle  re- 
main pendent  in  a  globular  form  to  the  buccal  cavity  of  a  Vorticella,  ''  when, 
by  the  decomposition  of  the  sarcode  and  the  evolution  of  a  swarm  of  rapidly- 
moving  monadic  particles,  these  two  organs,  with  the  cylindrical  nucleus  or 
gland,  though  still  slightly  adhering  to  each  other,  were  so  dissected  out  as 
to  be  nearly  separate  ;  and  thus  yielding  in  position  from  time  to  time,  as  they 
were  struck  by  the  little  particles,  their  fonns  and  relative  positions  respect- 
ively became  particularly  e\ident."  Moreover,  Lachmann  {A.  N.  H.  1857, 
xix.  p.  ''Z^Q)  argues  at  length  in  favour  of  the  true  vesicular  character  of 
contractile  spaces.  Thus  he  remarks — "  The  mode  of  contraction,  which 
differs  from  the  other  contractile  phenomena  of  _the  parenchyma  of  the  body, 
appears  to  speak  decidedly  in  favour  of  the  vesicular  nature  of  the  contractile 
space.  The  circumstance  that,  before  its  complete  expansion,  it  frequently 
appears  to  be  di\ided  into  two  or  three,  is  not  opposed  to  this,  as  a  vesicle 
may  very  weU  be  constricted  into  two  or  more  parts  by  the  partial  contrac- 
tion of  annular  portions,  or  by  strictures.  Some  other  facts  appear  to  be  ia 
favour  of  the  vesicular  nature  of  the  contractile  space,  such  as  the  phaenomenon 
presented  by  Spirostomum  amhiguum,  already  referred  to,  in  which  balls  of 
excrement  pass  to  the  anus  between  the  contractile  space  and  the  outer  skin 
of  the  animal,  and,  although  often  arching  the  waU  of  the  contractile  space 
into  a  semiglobular  form,  yet  never  break  through  into  it.     In  Actinoj)hrys,  the 


OF  THE  PEOTOZOA. CILIATA.  315 

supposition  that  there  is  a  membranous  boundary,  at  least  on  the  outside  of 
the  contractile  vesicle,  can  hardly  be  rejected,  as  its  wall,  which  is  situated 
on  the  outermost  surface  of  the  body,  must  biu-st  at  the  moment  of  greatest 
expansion,  if  it  were  only  composed  of  the  gelatinous  parenchyma  of  the 
body." 

Still  the  contrary  opinion,  viz.  that  the  contractile  spaces  are  mere  vacuoles 
in  the  substance  of  the  interior,  without  a  limiting  membrane,  has  found  able 
supporters  in  Meyen,  Dujardin,  Stein,  and  Perty.  The  first-named  writer 
compares  them  to  the  changing  vacuoles  which  spontaneously  generate  in 
the  vegetable  protoplasm  of  plant- cells,  by  an  inherent  property  or  process 
knoT\Ti  as  that  of  vacuolation,  and  which  is  equally  a  phenomenon  of  simple 
animal  protoplasm  or  contractile  tissue.  Indeed,  there  is  no  doubt  that  clear 
hollow  spaces  or  vacuoles  may  appear  and  disappear  within  the  substance  of 
Protozoa,  and  that  some  of  those  remarked  by  Dujardin,  Siebold,  and  others 
immediately  beneath  the  integument  were  of  this  number ;  yet  such  vacuoles 
want  the  constancy  in  position,  figui^e,  and  pulsating  power  belonging  to  true 
contractile  sacs.  Besides,  as  we  shall  presently  see,  the  evident  ramifications 
or  canalicuh  of  many  contractile  vesicles  among  the  Cihata  afford  further 
groimds  for  distinguishing  between  these  and  mere  vacuoles,  which,  as  far  as 
we  are  aware,  never  have  such  offshoots. 

Another  questionable  point  among  observers  is,  whether  any  communica- 
tion exists  between  the  cavity  of  the  contractile  vesicle  and  the  free  surface 
near  to  which  it  is  placed.  The  majority  concur  in  the  negative ;  but  several, 
among  whom  are  Oscar  Schmidt  {Froriep^s  Notiz.,  1849,  vol.  ix. ;  Lehrhuch 
der  Vergleichend.  Anatomie,  1853),  Mr.  Gray  {Silliman's  Journ.  1853),  Mr. 
Rood  (SiUiman''s  Journ.  1853,  p.  70),  and  Mr.  Carter,  are  of  oj)inion  that  a 
du^ect  communication,  between  the  fluid  contents  of  the  vesicle  and  the  watery 
medium  bathing  the  external  surface,  is  established  by  means  of  foramina  in 
the  walls.  On  this  question  Lachmann  remarks  (op.  cU.  p.  227) — "  In  many 
Infusoria  we  see  one  or  more  pale  spots  upon  the  contractile  vesicle,  which 
may  easily  be  mistaken  for  orifices,  but  on  closer  examination  prove  to  be 
only  thin  spots  in  the  parenchyma  of  the  body  and  the  skin,  by  which  the 
action  of  the  external  water  upon  the  contents  of  the  vascular  system  is 
certainly  facilitated,  so  that  they  probably  serve  for  respii'atory  purposes. 
These  round  clear  spots  are  particularly  numerous  upon  the  contractile  space 
of  Spirostomum  ambiguum.'^  The  admission  or  the  denial  of  such  a  commu- 
nication will  very  much  affect  the  opinion  held  concerning  the  nature  of  the 
office  performed  by  the  vesicle,  to  which  we  shaU  immediately  advert. 

The  superficial  vesicles  or  vacuoles  before  aUuded  to,  considered  by  Dujardin 
of  the  same  nature  as  the  contractile  vesicle  itself,  have  not  been  sufiiciently 
examined  and  defined  of  late  to  warrant  a  conclusion  as  to  their  real  cha- 
racter :  yet  probably  some  of  those  spaces  are  no  more  than  mere  vacuolae, 
whilst  others  are  dilatations  of  the  channels  of  the  ramified  vascular  system. 
Mr.  Carter  would  in  general  assign  to  them  the  latter  character.  However, 
we  beheve  that  many  of  those  which  have  attracted  attention  have  been 
isolated  vesicles,  developed  from  time  time,  and  to  be  concerned  in  securing 
a  more  perfect  aeration  of  the  contained  fluid.  Siebold,  indeed,  went  so  far 
as  to  presume  they  opened  upon  the  external  surface,  and  brought  their  con- 
tents into  relation  Mdth  the  surrounding  water. 

In  figure,  contractile  spaces  are,  for  the  most  part,  round  or  somewhat 
oval,  and  as  to  size  stand  in  no  direct  relation  with  that  of  the  animalcules 
they  appertain  to.  Examples  of  the  prevailing  figiu^e  are  seen  in  Ophrydiimi, 
Zooihamnium,  ChiJodon,  Colpoda,  Trichodma,  &c.  Even  in  some  of  these  appa- 
rently simple  globular  sacs,  Mr.  Carter  discovered  a  series  of  spherical  sinuses 


316  GENERAL  HISTORY  OE  THE  INFIISORIA. 

suiToimding  and  communicating  dii-ectly  \Yith  them.  These  accessory  vesicles, 
he  tells  us  {op.  cit.  p.  130),  are,  "  under  exhaustion  of  the  animalcule  from 
various  causes,  so  distended,  and  thus  so  approximated,  as  to  assume  the 
appearance  of  an  areolar  structure  immediately  in  contact  with  the  vesicula. 
Each  globular  sinus  would,  however,  appear  to  be  the  proximal  or  largest  of 
a  concatenation  of  smaller  ones,  which  diminish  in  size  with  their  distance 
from  the  vesicula."  This  account  tallies  with  that  recorded  by  Mr.  Samuelson 
(J.  M.  S.  1857,  p.  104),  respecting  the  single  globular  vesicle  of  Glaucoma 
scintillans,  which  ^'  when  it  contracts  forces  the  fluid  into  others  which 
appear  temporarily  formed  around  it ;  "  and  these,  by  contracting  in  their  turn, 
refill  the  central  vesicle. 

Besides  the  seemingly  simple  spherical  vesicles,  there  are  others  that  pre- 
sent evident  branches  and  a  different  figure.  Such,  for  instance,  are  the 
elongated  vascular  canal  of  Spirostomum,  and  the  annular  canal  with  its  row 
of  vesicles  down  the  side, — which  seem  capable  of  coalescing  into  a  continuous 
channel,  seen  in  Stentor  (XXIX.  7).  In  Paramecium  Aurelia  (XXV.  329), 
each  contractile  vesicle  assumes  a  stellate  form,  owing  to  the  radiating  pro- 
cesses it  sends  off  on  all  sides,  and  which  Eckhard  represented  as  prolonged 
through  the  body  by  interrupted  channels.  It  is  from  the  study  of  this 
Paramecium  especially,  that  observers  have  generally  arrived  at  the  belief  in 
the  existence  of  vascular  canals  in  the  Cihata,  connected  with  the  contractile 
vesicle  as  a  central  organ.  That  there  exists  a  vascular  system  more  or  less 
distributed  through  the  body,  most  recent  microscopists  are  in  accord :  we 
may  mention  Lieberkiihn,  Lachmann,  Mr.  Carter,  Professor  Busk,  and  Mr. 
Samuelson. 

As  this  apparatus  ^vill  be  best  considered  in  connexion  with  its  assigned 
functions,  we  shall  speak  of  them  together,  premising  oui'  account  with  the 
history  of  Ehrenberg's  conjectures  on  the  nature  and  function  of  the  con- 
tractile vesicle.  This  distinguished  naturahst  was  led  by  his  hypothesis  of 
organization  to  seek  for  each  of  the  organs  of  higher  animals  a  parallel  or 
analogue  in  the  Infusoria  ;  and  one  of  the  most  curious  analogies  he  hit  upon 
was  that  of  the  contractile  sac  with  the  spermatic  vesicle.  In  this  office  he 
represented  the  vesicle  as  receiving  from  the  testis  (nucleus)  a  reproductive 
fluid,  which  it  again  ejected  among  the  ova  (granules,  alimentary  vesicles, 
&c.)  occupying  the  interior  of  the  animalcule.  In  this  peculiar  notion 
Ehrenberg  has  met  with  few  disciples  :  for,  as  Siebold  has  justly  objected,  it 
is  a  perfectly  gratuitous  hypothesis,  without  analogy  in  the  animal  kingdom ; 
for  in  no  animal  is  such  a  thing  seen  as  an  incessant  projection  of  seminal 
fluid  into  the  interior  ;  and  further,  both  the  nature  of  the  nucleus  as  a  testis 
or  secretory  organ  of  spermatic  fluid,  and  the  existence  of  recipient  ova,  are 
at  best  very  doubtful  hypotheses. 

The  opinions  now  in  vogue  concerning  the  function  of  the  contractile 
vesicle  and  of  its  prolongations  or  processes  are  that  it  is  either  (1)  a  water- 
vascular  and  respiratory  system,  homologous  with  that  of  the  Rotatoria, 
or  (2)  homologous  with  a  blood-vascular  system,  or  (3)  an  excretory  appa- 
ratus. The  first  conjecture  presupposes  a  direct  commimication  between  the 
fluid  in  this  vascular  system  and  the  surrounding  aqueous  medium  ;  by  the 
second,  no  such  direct  communication  need  be  presumed ;  the  third  view  is 
especially  supported  by  Mr.  Carter,  Bergmann,  and  Leuckhart. 

In  his  notions  concerning  the  organization  and  function  of  the  contractile 
vesicle.  Stein  differs  from  most  other  recent  investigators.  As  we  have 
already  seen,  he  denies  a  limiting  membrane  to  the  vesicle ;  he,  moreover, 
can  neither  acquiesce  in  the  belief  of  the  existence  of  outlets,  nor  in  the 
respiratory  piu'posc  attributed  to  it  by  Siebold  and  0.  Schmidt.     He  is   even 


OF  THE  PROTOZOA. CILIATA,  317 

doubtful  of  the  stellate  structure,  as  an  actual  fact,  in  the  Paramecia  ;  for  in 
P.  Bursaria,  in  Nassida,  and  other  animalcules  this  apparent  structure  may- 
be, he  beheves,  produced  at  will  by  the  exercise  of  slight  pressui^e,  as  by  that 
of  the  thin  glass-cover  upon  the  object,  when  the  diastole  of  the  vesicle  is 
incomplete.  Again,  he  objects  against  the  supposed  water-vascular  system 
and  its  respiratory  office,  that,  in  comparison  to  the  large  ciliated  pharynx, 
within  which  a  fresh  supply  of  water  is  perpetually  introduced,  and  through 
whose  dehcate  walls  a  res23iratory  act  may  be  readily  conceived  to  take  place, 
the  small  contractile  space  commonly  appended  to  it  appears  of  inconsider- 
able importance  as  an  aerating  organ.  Further,  he  cannot  conceive  the 
necessity  of  a  respiratory  apparatus  in  any  animalcule  which  lives  surrounded 
on  all  sides  by  water,  besides  receiving  it  incessantly  within  its  interior,  and 
which  can  therefore  so  readily  absorb  its  oxygen  through  its  deKcate  tissues. 
Another  fact  adverse  to  this  assigned  function  is,  that  the  vesicles  of  embryos, 
whilst  stni  within  the  parent,  are  seen  in  full  activity,  although  in  that  posi- 
tion no  renewed  supply  of  fresh  water  is  afforded  them. 

These  objections  of  Stein  lessen  upon  consideration :  thus  his  opinion  that 
the  vesicle  is  a  mere  vacuole,  that  its  radiating  canals  are  probably  accidental 
appearances,  and  his  ignoring  the  existence  of  a  set  of  vascular  channels 
through  the  interior,  are  set  aside  by  the  direct  observations  of  several 
naturalists  to  the  contrary.  So,  although  his  arguments,  generally,  against 
the  presence  of  a  special  respiratory  apparatus  are  not  without  force,  yet  the 
remark  that  he  can  conceive  no  need  of  such  an  apparatus  in  animalcules  so 
cii'cumstanced  as  the  Ciliata  is  worthless  as  an  argument ;  for  in  all  such 
inquiries  into  the  phenomena  of  life  we  are  not  to  suppose  an  organization 
and  then  to  find  it,  but,  on  the  contrary,  to  discover  facts,  and  then,  if  possi- 
ble, to  determine  on  their  nature. 

That  the  contractile  vesicle  and  its  connected  channels  do  not  constitute  a 
water-vascular  and  respiratory  system,  is  also  the  opinion  of  Lachmann  and 
Carter.  The  former  able  observer  has  confirmed  and  extended  our  previous 
knowledge  of  the  vascular  apparatus,  and  thus  conveys  his  researches  and 
opinions  {op.  cit.  p.  224) : — "  When  the  contractile  space  (of  Pay^mecium 
Aurelid)  is  full  and  ^vide  open,  the  rays  can  only  be  observed  as  fine  lines,  or, 
when  the  light  is  not  good,  are  entirely  imperceptible  ;  by  the  sudden  con- 
traction of  the  space,  however,  they  instantly  swell  into  a  pyriform  com- 
mencement close  to  the  position  of  the  contractile  vesicle  which  has  disap- 
peared. "With  favoiu-able  illumination,  when  the  animals  possess  the  proper 
degree  of  transparency,  the  rays  may  be  traced  in  Paramecmm  Aurelia  across 
the  half  of  the  animal,  and  we  may  sometimes  perceive  a  bifurcation  of  one 
or  other  of  them.  During  the  slow  reappearance  of  the  contractile  space, 
the  rays  gradually  decrease ;  and  they  have  almost  entirely  disappeared,  or 
become  reduced  to  fine  lines,  when  the  vesicle  has  attained  its  fiill  extension. 
These  rays,  as  well  as  the  contractile  spaces,  lie,  as  in  all  Infusoria,  close 
under  the  skin  ('  cuticula '  of  Cohn),  in  the  parenchyma  of  the  body  ('  corti- 
cal layer'  or  '  cell-membrane  '  of  Cohn). 

"  In  many  Vortkellce  we  also  find  j)rocesses  going  off  from  the  contractile 
vesicle  (Ehrenberg  even  states  that  he  has  frequently  seen  the  contractile 
vesicle  of  Carchesium  polypinum  lobate  or  almost  radiate)  ;  of  these  I  have 
been  able  to  trace  one  particularly,  in  V.  yiebidifera,  V.  Campanula,  and  Carche- 
sium polypiyium,  up  to  close  beneath  the  skin  of  the  cihary  disk ;  this,  when 
seen  from  above,  exhibited  a  longish  section.  From  this  a  fine  branch  appears 
to  nm,  on  the  upper  wall  of  the  vestibulum,  transversely  across  this  to  the 
other  side ;  at  least,  I  have  seen  a  thin  process  hanging  down  like  a  short 
curtain  into  the  vestibulum  from  the  side  turned  towards  the  ciliary  disk. 


318  GENERAL  HISTORY  OF  THE  INFUSORIA. 

which  swelled  up  when  the  above-mentioned  process  became  enlarged  in  con- 
sequence of  the  contraction  of  the  vesicle. 

"  In  Dendrosoma  radians  (Ehr.),  a  fine  vessel  runs  through  the  whole 
length  of  the  body,  and  sends  branches  into  its  ramifications  :  it  is  furnished 
with  a  number  of  contractile  spaces,  partly  in  the  stem  and  partly  in  the 
branches. 

''  The  processes  of  the  contractile  space  are  seen  with  remarkable  distinct- 
ness in  the  large  Stentoi' polymori^hus  (including^.  RoeseUi  and  S.  Miilleri),  in 
which  a  very  considerable  portion  of  a  vascular  system  may  be  recognized. 
The  large  contractile  space  lies  a  little  to  the  left  of  the  oesophagus,  near  the 
plane  of  the  ciliaiy  disk.  From  it  a  longitudinal  vessel  nms  to  the  posterior 
extremity  of  the  animal,  and  an  annular  vessel  round  the  ciliary  disk  (Stirn) 
close  under  its  series  of  cilia.  Both  these  are  visible  even  during  the  expan- 
sion of  the  contractile  vesicle,  but  swell  up  suddenly  like  the  vessels  of  the 
above-mentioned  Infusoria  during  its  contraction  :  at  this  time  the  longitu- 
dinal vessel  usually  exhibits  considerable  dilatations,  which,  when  superfi- 
cially examined,  may  easily  be  taken  for  independent,  disunited  cavities 
(vacuoles).  The  annular  vessel  exhibits  a  more  uniform  lumen ;  only  two 
roundish  dilatations  make  their  appearance  in  it — one  close  to  the  anus  on  the 
dorsal  side  of  the  animal,  and  the  other  close  to  the  oesophagus  on  the  ventral 
surface.  Both  vessels  gradually  decrease  during  the  reappearance  of  the  con- 
tractile vesicle,  apparently  without  any  contraction  of  their  own,  in  the  same 
way  as  the  vessels  of  the  Paramecia.  The  longitudinal  vessel  of  the  Stentors, 
and  a  similar  one  in  Spirostomxmi  ambiguum,  were  first  described  by  Von  Sie- 
bold,  whilst  theii'  existence  has  been  erroneously  denied  by  Eckhard. 

"'  As  we  thus  find  a  vascular  system  in  the  Stentors,  and  in  other  Infusoria 
recognize  the  parts  lying  nearest  to  the  centre  (the  contractile  space)  some- 
times easily  and  sometimes  with  difficulty,  we  may  certainly  conclude  that 
such  a  system  exists  in  all  Infusoria  which  possess  a  contractile  space,  even 
when  no  branches  have  been  detected  running  out  from  this.  That  this 
system  does  not  merely  consist  of  accidental  chasms  in  the  parenchyma  of  the 
body  (vacuoles  of  Dujardin),  is  apparent  fi'om  its  regularity.  When  it  is  as- 
serted, in  proof  of  the  inconstancy  of  these  vacuoles,  that  exactly  similar  ones 
frequently  make  theii'  appearance  in  other  parts  of  the  body,  this  appears  to 
me  to  arise  from  very  different  things  being  confounded  together.  The  swell- 
ing dilatations  of  existing  vessels  are  certainly  often  regarded  as  such  vacu- 
oles, without  its  being  remembered  that  these  dilatations  always  gradually 
decrease  again,  whilst  the  true  vascular  centres,  the  contractile  spaces,  always 
diminish  suddenly  in  healthy  animals.  Moreover,  in  diseased  Infusoria,  an 
exudation  of  a  fluid,  with  which  the  parenchyma  is  normally  imbued,  appears 
to  take  place  from  it  even  into  the  cavity  of  the  body,  and  perhaps  into  chasms 
of  the  parenchyma,  as  we  often  see  it  take  place  in  Infusoria  and  many  other 
low  invertebrate  animals,  on  the  suiface  of  the  body.  These  sarcode-drops 
appear  to  be  incapable  of  ever  being  again  absorbed ;  but  their  formation 
always  appears  to  lead,  although  slowly,  to  the  death  of  the  animal." 

After  the  above  details,  Lachmann  inquires  the  nature  of  the  fimction  this 
vascular  apparatus  performs ;  and  having  satisfied  himself  of  the  nonexistence 
of  a  communication  between  the  interior  of  the  vesicle  and  the  external  sur- 
face, he  rejects  the  idea  of  its  being  a  water-vascular  system,  as  "  we  do  not 
possess  the  certain  proof  of  one  of  the  most  essential  requii-ements  of  a  water- 
vascular  system — the  existence  of  an  external  orifice, — and  some  things 
appear  directly  opposed  to  it." 

Mr.  Carter  coincides  with  Lachmann  in  many  particulars  respecting  the 
structure  of  the  vascular  system  of  Ciliata  ;  but  in  others  he  materially  differs  : 


OF  THE  PEOTOZOA. CILIATA.  319 

for  instance,  he  thinks  he  has  made  out  the  existence  of  apertm-es  opening 
on  the  free  surface  whether  of  the  alimentaiy  tube  or  of  the  general  integu- 
ment, close  to  one  or  other  of  which  he  always  finds  the  vesicle  ;  and,  with 
this  view  of  the  structure,  he  connects  the  function  of  an  excretory  organ 
with  the  sac  in  question. 

To  support  this  ^iew  respecting  the  ofiice  of  the  contractile  vesicle,  he  ad- 
vances the  following  observations  {op.  cit.  p.  126) : — "  1st.  It  is  always  seen 
either  close  to  the  pellicula  or  close  to  the  buccal  cavity,  and  always  sta- 
tionary. Thus,  in  Paramecium  Aurelia  it  is  close  to  the  surface,  and  although 
it,  of  coiu'se,  passes  out  of  view  as  the  animalcule  tiu-ns  on  its  long  axis,  yet 
it  always  reappears,  after  contraction,  in  the  same  place, — while  in  Vorticella 
it  is  attached  to  the  buccal  ca^dty,  and,  being  centricaUy  situated,  seldom 
passes  out  of  view,  except  when  it  disappears  under  contraction,  after  which 
it  also  reappears  in  the  same  place. 

"  2nd.  In  Actinophrys  Sol  and  other  Amoeha^,  during  the  act  of  dilatation, 
the  vesicula  projects  far  above  the  level  of  the  pellicula,  even  so  much  so  as 
occasionally  to  form  an  elongated,  transparent,  mammilliform  eminence, 
which,  at  the  moment  of  contraction,  subsides  precisely  like  a  blister  of  some 
soft  tenacious  substance  that  has  just  been  pricked  with  a  pin. 

"  3rd.  Lastly,  when  we  watch  the  contraction  of  the  vesicula  in  a  recently 
encysted  Vorticella,  we  observe  that  at  the  same  moment  that  it  contracts 
the  buccal  cavity  becomes  filled  with  fluid,  and,  further,  that  this  fluid  dis- 
appears from  the  buccal  canity,  and  all  trace  of  the  latter  "uith  it,  long  before 
the  vesicula  reappears, — thus  proving  at  once  that  the  fluid  comes  from  the 
vesicula,  and  does  not  return  to  it,  whatever  may  become  of  it  afterwards. 

"  The  position  of  this  organ,  then,  its  manner  of  contracting,  and  the  buccal 
cavity  of  encysted  Vorticella  becoming  filled  with  fluid  the  moment  it  disap- 
pears (where  we  know  it  to  be  attached  to  the  buccal  cavity,  and  not  to  the 
peUieula),  are  almost  conclusive  of  its  excretory  office." 

Adopting  SpaUanzani's  observation  (which,  however,  wants  confirmation  to 
estabhsh  it  as  the  rule)  that  the  fusiform  sinuses  of  Paramecium  Aurelia  be- 
come empty  as  the  vesicle  fills,  and  do  not  reappear  until  some  time  after  it 
has  contracted,  he  infers  "  that  the  fluid  with  which  the  vesicula  is  distended 
comes  through  the  sinuses,  but  is  not  returned  by  them  to  the  body  of  the 
Paramecium^ 

'■'■  Xow  ia  some  cases,"  he  continues,  "  faint  hyaline  or  transparent  lines 
may  be  seen  to  extend  outwards  from  each  of  these  sinuses,  which  Hnes, 
Eckhard  has  stated,  '  traverse  the  body  in  a  stellate  manner.'  Hence,  w^hen 
we  add  Eckhard's  evidence  (which  I  have  been  able  to  confirm  in  a  way  that 
will  be  presently  described)  to  the  observation  of  SpaUanzani,  and  connect 
this  with  the  facts  abeady  adduced  in  favour  of  the  excretory  office  of  the 
vesicula,  it  does  not  seem  unreasonable  to  conclude  that  the  whole  together 
forms  an  excretory  vascular  system,  in  which  the  vesicula  is  the  chief  recep- 
tacle and  organ  of  expulsion. 

**  While  watching  Paramecium  Aurelia,  I  on  several  occasions  not  only  ob- 
served that  the  vesiculae  were  respectively  suiTounded  by  from  seven  to 
twelve  pyriform  sinuses  of  different  sizes,  and  that  lines  extended  outwards 
from  them  in  the  manner  described  by  Eckhard,  but  I  further  observed  that 
these  lines  were  composed  of  a  series  of  pyiiform  or  fusiform  sinuses,  which 
diminished  in  size  outwards ;  and  frequently  I  could  trace  as  many  as  three 
in  succession,  including  the  one  next  the  vesicula.  Hence  I  am  inclined  to 
infer  that  this  vascular  system  throughout  is  more  or  less  composed  of  chains 
of  such  sinuses,  and  that  aU  have  more  or  less  contractile  power  like  that  of 
the  vesicula.  Just  preceding  death,  when  Paramecium  A^irelia  is  compressed. 


320  GENERAL  HISTORY  OF  THE  INTUSORIA. 

and  under  other  favourable  circumstances,  these  sinuses  run  into  continuous 
hyaline  lines,  and  may  not  only  be  seen  extending  in  a  radiated  vascular 
fonn  across  the  animalcule,  but  even  branching  out  roimd  the  position  of  the 
vesicula,  which,  having  now  become  permanently  contracted,  has  thus  poured 
back  the  contents  which  render  them  visible.  They  enter  the  lower  or  inner 
part  of  the  organ,  and  at  this  point,  therefore,  are  pushed  inward  as  the  vesi- 
cula becomes  distended.  Under  the  same  circumstances,  also,  when  the  vesi- 
cula is  slowly  dilating  and  eontractiug,  it  may  be  seen  to  be  attached  to  a 
small  papilla  on  the  surface,  about  twice  the  diameter  of  those  which  sur- 
mount the  trichocysts,  and  through  which  it  probably  empties  itself  (XXYIII. 
25).  In  Otostoma  theie  appears  to  be  a  similar  arrangement  of  vesicles  round 
each  vesicula ;  and  here  also  they  seemed  to  me  to  be  branched — at  least 
such  was  my  impression  after  having  watched  this  animalcule  for  a  long  time 
in  order  to  determine  the  point." 

"  Of  the  use  of  the  vesicula  and  its  vascular  system,"  Mr.  Carter  concludes, 
<*  we  are  at  present  ignorant,  fiu'ther  than  that  its  fimctions  are  excretory ; 
and  when  we  observe  the  quantity  of  water  that  is  taken  into  the  sarcode 
with  the  food,  and  try  to  account  for  its  disappearance,  it  does  not  seem 
improbable  that  the  vesicula  and  its  vessels  should  be  chiefly  concerned  in 
thi^  office.  Another  service,  however,  which  it  performs,  is  to  bui'st  the 
spherical  membranes  of  Vorticellce  and  Plcesconice  when  they  want  to  retui^n 
to  active  life  after  having  become  encysted :  this  it  effects  by  repeated  dis- 
tension, until  the  lacerated  cyst  gives  way  sufficiently  for  the  animalcule  to 
slip  out." 

"  Should  it  have  any  other  uses,  they  are  probably  similar  to  those  of  the 
'  water-vascular  system  '  of  Rotifera.^" 

In  answer  to  the  question,  if  all  vacuolar  spaces,  excepting  those  produced 
by  the  deglutition  of  food,  belong  to  this  excretory  system  of  contractile  si- 
nuses, he  replies — "  Certainly,  where  there  is  a  pluraHtj^  of  actively- con- 
tracting vesicles  without  the  appearance  of  the  vesicula,  as  in  Chilodon  Cucul- 
lulus,  we  may,  as  before  stated,  attribute  this  to  a  kind  of  over- irritability  or 
constrictive  spasm  of  the  vesicula,  and  therefore  consider  that  these  vesicles 
are  accidental  dilatations  of  the  sinuses  in  connexion  with  it,  as  we  may  set 
down  the  dropsical  state  of  Himantophorus  Cfliaron  (Ehr.),  and  other  animal- 
cules of  the  kind,  to  an  opposite  condition  of  this  organ,  viz.  that  in  which  it 
is  unable  to  reheve  itself  of  its  contents :  this  I  have  often  seen  occur  under 
my  own  eyes." 

Many  thanks  are  due  to  Mr.  Carter  for  his  painstaking  investigation  on 
this  subject.  We  are  nevertheless  very  doubtful  of  several  of  his  details  of 
structure.  For  example,  he  describes  globular  sinuses  to  ajDpear  around  the 
vesicle  when  an  animalcule  is  exhausted,  and  those  of  Paramecium  to  run 
into  radiating  hyaline  (monihform)  lines  just  before  death  and  under  a 
certain  amount  of  compression.  Now,  such  conditions  are  ill-adapted  to 
accurate  research  ;  and  knowing  how  readily  the  integrity  of  the  soft  filmy 
substance  of  the  Protozoa  is  distm-bed,  and  diffluence  induced,  by  unfavoiu^able 
external  circumstances,  the  observation  in  question  must  be  received  "  cwn 
grano  salis.'^  Moreover,  looking  to  most  of  his  figui'es  (which,  we  regret, 
are  rather  diagrams  than  exact  delineations  after  nature),  the  impression 
forces  itself  upon  the  mind,  that  he  has  many  times  mistaken  the  commence- 
ment of  diffluence,  and,  in  some  instances,  vacuolation  resulting  from  the 
entrance  of  water  into  the  tissues,  for  the  manifestation  of  sinuses  about 
the  contractile  vesicle  or  scattered  over  the  body  in  connexion  with  it. 
Thus  we  should  rather  attribute  the  several  vesicles  this  naturalist  saw  in 
different  numbers,  and  variously  and  irregularly  dispersed,  in  different  spe- 


OF  THE  PROTOZOA. CILIATA.  321 

cimens  of  ChiUdon  CucuUulus,  to  one  or  other  or  to  both  of  the  conditions  we 
have  mentioned,  than  to  the  purely  hypothetical  notion  of  the  presence  of  a 
state  of  "  over-ii-ritability "  in  a  presumed  vascular  network.  It  is  here 
worth  calling  to  mind  Stein's  belief  that  gentle  pressure  may  give  rise  to  a 
stellate  or  branched  appearance  of  the  vesicle,  and  that  the  conflicting  ac- 
counts between  Ehrenberg  and  Focke  are  reconcileable  on  the  supposition 
of  this  occurrence  (Stein,  p.  240). 

With  reference  to  the  hypothesis  that  the  vascular  apparatus  is  only  ex- 
cretory in  function,  we  may  remark  that  the  exercise  of  such  an  office  is  no 
bar  to  that  of  a  respiratory  function,  since  the  latter  is  in  itself  in  part  an 
excretoiy  process,  and  among  the  lower  Invertebrata  many  examples  might 
be  cited  where  one  and  the  same  mechanism  is  equally  respiratory  and  ex- 
cretoiy in  purpose. 

We  may  add  that  Mr.  Samuelson  (J.  M.  S.  1857,  p.  105)  agrees  with 
Lachmann  in  attributing  to  the  contractile  vesicle  a  cardiac  nature,  and  sup- 
phes  the  following  particulars: — "In  Paramecium  caudatum  a  species  of 
Amphileptus,  a  freed  Vorticella,  &c.,  I  have  frequently  and  clearly  traced 
the  canals  that  empty  themselves  into  the  contractile  vesicle.  In  the  second- 
named  species  these  canals  were  very  perceptible  ;  they  proceeded  along  the 
edge  of  the  body  where  the  cilia  were  the  most  active  (also  probably  because 
there  the  ciuTent  of  fresh  water  would  be  constantly  renewed),  and,  at  the 
embouchure  into  the  central  vesicle,  swelled  into  a  biilb-shape.  In  the  Vor- 
ticella, the  cordractile  vesicle  had  a  canal  which  either  communicated  with  the 
external  surface  through  the  oral  aperture,  or  passed  round  the  oral  wreath. 
I  was  inclined  to  beheve  the  latter  to  be  the  case  (perhaps  my  bias  may  have 
influenced  the  observation). 

"  In  certarcL  Infusoria  there  appears  to  be  a  more  active  vital  power  than 

in  others.     Thus  in  Glaucoma (especially  such  as  are  probably  lai-val 

forms),  the  contractile  vesicle  appears  to  have  the  power  only  to  form  a  row 
of  auxiliary  vesicles  around  it,  whilst  in  Ami^hileptus  (which  approaches  the 
Planaiians  in  its  character),  the  Setifera  or  bristle-bearers,  and  other  types 
it  is  more  powerful,  and  the  fluid  is  ejected  with  sufficient  force  to  work  its 
way  into  the  body,  and  form  canals  or  arteries,  however  primitive  they  may 
be.  The  progressive  vitality  I  have  often  noticed  in  the  same  form  at  dif- 
ferent stages  of  its  growth." 

On  a  survey  of  the  facts  and  opinions  now  passed  in  review,  it  seems  to  us 
that  the  contractile  vesicle  is  a  closed  sac  representing  a  central  circulatory 
organ  or  heart  in  its  most  rudimentary  condition  ;  that  this  cardiac  sac  pro- 
pels its  contents  through  a  more  or  less  complex  system  of  channels,  probably 
walled,  extended  through  the  cortical  lamina  of  the  body ;  that  the  contents 
represent  a  chyle  or  blood,  formed  by  the  process  of  digestion,  and  absorbed 
by  the  vessels ;  that  this  chyle  is  exposed  in  the  cardiac  pulsating  vesicle 
especially,  and  in  the  ramified  channels  less,  to  the  indirect  action  of  the  water 
incessantly  introduced  withia  the  body,  or  constantly  surrounding  it  exter- 
nally, and  thereby  becomes  aerated,  and  consequently  in  all  probability  fur- 
ther elaborated;  lastly,  that  the  perfected  chyle  is  circulated  through  its 
channels,  and  brought  by  them  into  the  immediate  vicinity  of  the  tissue  in 
which  the  most  active  vital  changes  are  going  on,  and  which,  on  account  of 
its  higher  differentiation,  especially  when  in  the  form  of  cilia,  integument, 
&c.,  demands  the  greatest  supply  of  nutritive  matters  to  repair  its  waste  and 
to  provide  for  the  processes  of  growth  and  development  perpetually  proceed- 
ing in  it  or  in  its  appended  organs. 

Since  the  foregoing  review  of  the  structure  and  fimctions  of  the  contractile 
vesicle  was  written,  Lieberkiihn's  valuable  contribution,  founded  on  original 


322  GENERAL  HISTOET  OF  THE  INFUSORIA. 

researches  chiefly  concerning  Bursaria  and  Ophryoglena,  have  come  into  our 
hands  {A.  N.  H.  1856,  xviii.  p.  323).  Since  the  introduction  of  it  piecemeal 
in  our  history  of  the  organ  would  both  have  sacrificed  its  merits  as  an  original 
essay  and  have  disturbed  the  continuity  of  our  own  account,  we  have  deter- 
mined to  reproduce  it  here  as  a  supplement. 

After  describing  the  existence  of  two  vesicles  in  Ophryoglena  and  Bursaria, 
one  near  the  mouth,  the  other  situated  jDosteriorly,  he  goes  on  to  say  that  if 
we  examine  a  Bursaria  fiava  containing  only  the  smallest  forms  of  the 
strongly  refractive  granules,  "  with  a  power  of  300  diameters,  we  perceive 
near  the  surface  a  quantity  of  light  streaks,  which  run  together  towards  the 
contractile  vesicle  from  the  anterior  and  posterior  parts  of  the  body,  in  more 
or  less  considerable  curves.  In  each  streak  we  detect  an  extremely  delicate 
but  perfectly  distinct  canal,  terminating  ultimately  in  the  contractile  vesicle ; 
its  walls  and  its  contents  are  readily  distinguished  by  theii'  different  refrac- 
tive power.  When  one  of  these  canals  is  traced  backwards  from  its  orifice, 
we  may  often  perceive,  after  it  has  run  a  short  distance,  a  ramification  :  this 
may  frequently  be  traced  to  one  of  the  extremities  of  the  body,  and  some- 
times it  gives  off"  another  branch  ;  ultimately  the  canals  become  so  excessively 
fine  that  they  are  invisible.  Their  opening  into  the  vesicle  and  their  course 
in  running  from  it  are  seen  very  distinctly  when  the  contractile  vesicle  is 
turned  dii-ectly  upwards ;  we  may  then  recognize  how  the  canals  run  between 
the  contractile  reservoirs,  which  lie  very  close  to  the  surface  of  the  body,  and 
between  the  surfaces  of  the  body  inside  the  cortical  substance  ;  and  the  ori- 
fices may  likewise  be  seen.  Another  remarkable  position  is  when  the  nucleus 
is  turned  next  the  observer  at  the  surface  of  the  body  ;  the  canals  are  then 
seen  remarkably  clearly  on  its  bright  background.  A  few  canals  always  run 
over  directly,  with  a  slight  cui-vatm-e,  towards  the  posterior  part  of  the  mouth. 
"When  the  animalcule  lies  so  that  the  contractile  vesicle  appears  at  the 
margin  of  the  body,  there  is  sometimes  an  appearance  as  if  one  or  more  of 
the  canals  opened  externally  at  this  point ;  but  close  examination  shows  that 
they  ciuwe  round  and  run  towards  other  parts  of  the  body. 

^'  The  number  of  vessels  opening  into  the  contractile  vesicle  in  Bursaria 
flava  is  about  thirty ;  this  number,  or  a  few  more  or  less,  existed  in  all  the 
specimens  which  I  examined  in  reference  to  this  point.  They  are  apparently 
imiformly  distributed  over  the  whole  surface. 

^'  The  specimens  of  Bursaria  flava  with  two  contractile  vesicles  have  the 
system  of  canals  double,  each  system  grouped  independently  around  its  re- 
servoir. The  canals  of  the  posterior  reservoir  stretch  into  the  district  of  the 
anterior ;  but  I  have  never  been  able  to  detect  any  communication  between 
the  two.  In  the  Ophryoglence  from  the  Spree  very  httle  could  be  detected 
of  the  canals,  even  when  the  interior  of  the  body  contained  only  slightly  re- 
fractive substances.  When  a  suitable  sj)ecimen  is  somewhat  compressed  be- 
tween the  glasses,  so  that  it  cannot  move  about,  the  vessels  are  especially 
seen  when  they  have  the  nucleus  for  a  background,  and  when  they  end  in 
the  contractile  vesicle. 

"'  I  have  never  been  able  to  trace  any  vessels  into  the  interior  of  the  body 
— for  instance,  towards  the  nucleus.  I  am  also  ignorant  at  present  whether 
that  part  of  the  contractile  vesicle  which  is  turned  toward  the  centre  of  the 
body  of  the  animalcule  receives  any  vessels. 

''Both  Bursaria  flava  and  Ophryoglena  flavicans  belong  to  those  Infusoria 
in  which  the  contractile  reservoii^s  may  assume  the  weU-lmown  stellate  form. 
Yon  Siebold  describes  this  phenomenon  in  Paramecium  in  the  following 
words  : — '  These  pulsating  spaces  have  a  very  striking  shape ;  they  consist  of 
two  central  round  cavities,  around  which  stand  from  five  to  seven  smaller 


OF  THE  PROTOZOA. CILIATA.  323 

pear-shaped  reservoirs,  vdth  points  directed  outwards  in  the  shape  of  a 
star.  In  the  pulsation  of  these  strange  star-shaped  reservoii's  sometimes 
the  stars  disappear  entirely,  sometimes  only  the  central  roimd  spaces,  and 
sometimes  only  the  rays.'  The  opaque  Bursarice  exhibit  this  phenomenon 
just  in  the  same  way  as  it  is  described  by  Yon  Siebold ;  and  those  speci- 
mens in  which  the  vascular  system  can  be  detected,  offer  the  explanation 
of  it.  The  small  pear-shaped  spaces  are  really  the  commencciments  of  the 
vessels,  which  expand  with  the  accumulated  fluid ;  and  the  rays  are  the 
further  prolongations  of  the  same,  which  may  be  traced  to  the  ends  of  the 
body. 

"  At  the  moment  when  the  contractile  vesicle  has  attained  the  greatest  ex- 
pansion (that  is,  when  the  diastole  is  terminated),  it  appears  in  the  form  of  a 
globe  filled  T\ith  colourless  fluid,  from  which  the  vessels  run  out  on  all  sides 
in  the  cortical  substance  as  canals,  apparently  of  equal  diameter ;  they  have 
at  this  time  the  smallest  diameter  they  can  assume  at  their  embouchure  into 
the  reservoir.  In  opaque  specimens,  this  is  the  moment  when  the  opened 
contractile  vesicle  is  observed.  A  little  before  we  observe  the  commencement 
of  the  systole,  the  vessels  begin  to  expand  slowly,  at  points  distant  about  one 
diameter  of  the  contractile  vesicle  from  the  surface  of  the  latter,  to  many  times 
their  original  size.  The  more  the  systole  progresses,  the  wider  and  longer 
become  the  swoUen  places,  and  they  approach  gradually  to  the  contractile 
vesicle.  If  we  make  an  observation  at  the  moment  when  the  diameter  of  the 
contractile  vesicle  is  diminished  to  about  one-fom^th  of  its  original  size,  the 
shape  of  the  apparatus  agrees  in  all  essential  points  with  the  weU-known 
stellate  figure  represented  by  Dujardin  in  Paramecium  Aurella,  with  the 
single  exception  that  the  embouchui^es  of  the  rays  are  distinctly  visible,  and 
theu'  peripheral  prolongations  run  out  widely  in  the  form  of  canals  over  the 
entire  animalcule.  Opaque  specimens  of  the  Bursaria  display  the  phenome- 
non only  in  such  a  degree  that  the  rays  terminate  in  delicate  attenuated 
points,  at  a  distance  of  about  one  diameter  of  the  reservoir  from  the  latter. 
When  the  contractile  vesicle  has  closed  completely,  the  fusiformly- expanded 
vessels  only  are  seen,  as  they  run  together  with  theu'  apices  to  one  point. 
This  completes  the  systole.  The  diastole  then  recommences.  If  we  examine 
the  animal  at  the  moment  when  the  reservoir  has  again  attained  half  its 
greatest  diameter,  we  find  a  totally  different  appearance  fi^om  that  at  the  cor- 
responding epoch  of  the  systole.  The  vessels  are  not  expanded  now  in  the 
form  of  a  spindle,  but  of  a  funnel,  with  the  base  of  the  funnel  in  the  contrac- 
tile vesicle,  and  the  point  prolonged  out  into  the  vessel.  This  is  the  form 
which  Ehrenberg  has  figured  in  Paramecium  Aurella,  only  omitting  the  fur- 
ther prolongations  of  the  vessels.  Yon  Siebold  rejects  Ehrenberg's  figure 
and  recognizes  Dujardin's;  but  both  are  really  correct,  only  representing 
different  instants ;  Dujardin  gives  a  stage  of  the  systole,  Ehi'enberg  of  the 
diastole. 

"  The  more  the  contractile  vesicle  now  expands,  the  more  is  the  depth  of 
the  funnel  decreased,  and  its  diameter  proportionately  increased  ;  or,  in  other 
words,  the  vessel  expands  only  at  its  embouchure,  and  the  depth  of  the  ex- 
panded part  decreases  in  proportion  with  the  advance  of  the  diastole.  In 
opaque  Bursarice  we  see  at  this  time  only  the  contractile  vesicle  produced  out 
in  various  directions  into  short  funnel-shaped  processes.  By  degrees  these 
processes  entii^ely  disappear, — the  contractile  vesicle  having  expanded  to  its 
original  volume.  We  now  see  again  how,  from  the  fully-expanded  contrac- 
tile vesicle,  the  whole  of  the  vessels  run  out  in  the  cortical  layer,  in  aU  di- 
rections, as  slender  streaks ;  in  opaque  specimens  only  the  contractile  reser- 
voii'  is  visible. 

y2 


324  GENERAL  HISTOHY  OF  THE  INFUSORIA. 

"  The  processes  above  described  are  those  usually  observed  when  a  suitable 
specimen  is  placed  so  that  it  cannot  move,  or  only  move  very  little,  upon  the 
slider.  If,  however,  a  Bursaria  is  compressed  somewhat  more  with  the  co- 
vering-glass, or  if  the  water  on  the  slider  is  almost  all  evaporated,  some  other 
peculiar  phenomena  present  themselves,  not  only  in  the  contractile  vesicle, 
but  in  the  vessels.  The  last  diastole  coming  perfectly  to  rest,  and  nothing 
unusual  being  observed,  except  that  the  reservoir  is  more  elongated,  with  the 
systole  appear  suddenly  two  contractile  vesicles  instead  of  one ;  that  is,  a 
portion  of  the  surrounding  substance  makes  its  way  across  the  middle  of  the 
contractile  vesicle  while  it  is  contracting,  and  thus  divides  it  into  two  parts. 
Each  of  these  two  new  reservoirs  has  its  own  systole  and  diastole.  In- most 
cases  their  contractions  do  not  occur  at  the  same  moment.  Each  is  in  con- 
nexion with  those  vessels  which  opened  into  it  before  the  separation.  The 
vessels  exhibit  the  same  play  as  if  there  were  but  one  uninjured  contractile 
vesicle.  Sometimes  the  two  reservoirs  reunite  into  a  single  one.  I  saw  this 
happen  duiing  a  diastole  which  occurred  exactly  simultaneously  in  both  :  they 
advanced  near  together,  projected  out  points  toward  each  each  other,  which 
came  in  contact  and  formed  a  dumb -bell- shaped  reservoir ;  and  this  was  ra- 
pidly converted  into  a  globular  vesicle,  which  contracted  and  expanded  as  at 
the  origin. 

"  Yon  Siebold  has  already  observed  in  Phialina  vermicularis,  Bursaria 
cordiformis,  &c.,  '  that  in  strong  contractions  of  the  whole  body,  a  largish 
round  pulsating  space  was  di-awn  out  longitudinally,  constricted  in  the  mid- 
dle, and  at  length  was  separated  into  two  smaller  round  spaces — exactly  as 
occurs  when  a  drop  of  oil  is  separated  into  two  portions.'  During  the  above- 
described  alterations  in  the  contractile  vesicles,  alterations  ordinarily  take 
place  in  the  vessels  also.  Thus  expansions  appear  in  them  at  points  lying 
very  distant  from  the  contractile  reservoii^s.  These  enlargements  are  not, 
however,  subject  to  rhythmical  disappearance  and  reappearance,  but  are  per- 
manent ;  they  are  filled  with  the  same  colourless  fluid  as  the  contractile  vesi- 
cles, and  are  mostly  globular  or  ellipsoidal.  If  such  enlargements  of  the  vessels 
are  seen  in  specimens  which,  from  unfavourable  optical  conditions,  do  not 
display  the  vessels  themselves,  they  may  be  taken  for  vacuoles  (in  Dujardin's 
sense).  Their  connexion  with  the  vessels,  and  their  mode  of  origin,  which 
is  readily  accessible  to  observation,  prove  that  they  are  totally  distinct  from 
the  vacuoles  in  the  interior  of  the  body,  part  of  which  contain  nutrient  sub- 
stance, while  part  do  not. 

"  I  have  not  succeeded  in  any  ease  in  isolating  a  membrane  of  the  contrac- 
tile reservoir  or  of  the  vessels.  I  find  no  trace  of  cilia  in  the  interior  of  the 
vascular  system.  This  alone  suflices  to  distinguish  essentially  those  Infusoria 
furnished  with  vessels  from  the  Distoma-Qmbijo  in  which  G.  E.  Wagener  has 
discovered  ciliated  vessels. 

''  Diff'erent  hypotheses  have  been  put  forth  in  explanation  of  the  function 
of  the  contractile  vesicles.  There  is  a  detailed  account  of  these  in  Claparede's 
paper  on  Actinophrys.  Claparede  rightly  explains  the  contradtHe  vesicles  as 
organs  of  the  cu^culation.  As  to  the  direction  in  which  the  fluid  flows  in  the 
vessels,  nothing  can  be  directly  observed  in  most  cases,  since  we  cannot  per- 
ceive in  the  fluid  any  solid  corpuscles  at  all  similar  to  the  blood-corpuscles  of 
other  animals.  Is  it  a  perfect  circulation  ?  or  does  the  fluid  flow  back  again 
in  the  same  vessel  in  which  it  has  been  propelled  forward  by  the  contractile 
vesicle  ?  or  are  the  contents  of  the  contractile  vesicles  constantly  expelled 
externally  ?  The  last  view  has  been  set  up  by  Oscar  Schmidt.  He  states 
that  he  has  seen  the  place  of  exit  in  the  genera  Bursaria  and  Paramecium. 
Claparede  is  opposed  to  this,  since,  in  the  most  minute  examination,  he  was 


OF  THE  PKOTOZOA. CILIATA.  325 

iinable  to  discover  that  the  contents  of  the  contractile  vesicle  were  expelled 
externally  in  the   systole.     Actinophrys  is  better  suited  to  the  settlement 
of  this  question  than  a  ciliated  Infusorium.     I  have  many  times  sought  for 
currents  in  the  fluid  siuTounding  Actinophrys  Sol  and  A.  Ekhhorn'ii,  when  the 
fluid  contained  masses  of  fine  globules  immediately  in  front  of  the  projection 
of  the  contractile  reservoir ;  but  I  have  never  seen,  any  more  than  Claparede, 
any  corresponding  displacement  when  the  vesicle  contracted.     In  Bursaria 
leucas,  B.  Vorticella,  Paramecium  Aurelia,  and  P.  Chrysalis,  I  obtained  the 
foUo^ving  results : — The  contraction  takes  place  exactly  in  the  manner  de- 
scribed by  Schmidt ;  the  vesicle  contracts  from  the  interior  of  the  animalcule 
towards  a  point  Ij^ng  near  the  surface,  and  it  expands  on  the  entrance  of  the 
fluid  in  such  a  manner  that  it  increases  in  diameter  gradually  from  the  surface 
of  the  animacule  inwards  toward  the  centre.     But  does  this  teach  us  what 
Schmidt  concludes  from  it,  that  the  reservoir  expels  its  contents  outwardly 
every  time  when  it  contracts  toward  the  outside,  and  becomes  filled  from  without 
when  it  expands  toward  the  interior  ?    If  the  contractile  reservoir  is  attached 
by  that  part  turned  toward  the  surface  of  the  animalcule  to  the  internal  surface 
of  the  cortical  substance,  while  the  portion  projecting  into  the  interior  of  the 
body  is  free  in  the  soft  medullary  mass,  will  not  the  contraction  take  place 
from  within  outwardly,  and  the  expansion  from  without  inward,  whether  the 
fluid  flow  inwards  or  outwards  ?    In  Actinophrys,  sometimes  in  Arcella  vul- 
garis, and  in  Urostyla  granclis,  a  totally  different  import  must  be  attributed 
to  the  contractile  reservoii',  if  Schmidt's  criterion  be  valid ;  for  here  the  re- 
servoir does  not  contract  toward  the  surface,  but  toward  the  interior  of  the 
body,  and  forms  an  elevation  on  the  surface  when  it  becomes  filled,  as  de- 
scribed minutely  in  Actinophrys  by  both  Yon  Siebold  and  Claparede.     But 
it  is  not  on  this  alone  that  Schmidt  rests  his  opinion  :  he  asserts  that  he  has 
observed  also  an  actual  external  orifice  of  the  contractile  vesicle.     I  must 
admit  that  Bursaria  Vorticella  has  a  distinct  orifice  at  the  hinder  part  of  the 
body,  and  this  exactly  at  the  place  to  which  the  contractile  vesicle  contracts 
until  it  vanishes.     But  regarding  this  orifice  which  I  saw,  only  so  much  is 
established — that  it  is  the  anal  orifice  which  Ehrenberg  has  already  described. 
I  have  seen  the  emergence  of  remains  of  devoured  substances,  of  loricae  of 
Bacillaria,  of  fine  undeterminable  granules,  &c.,  from  this  very  hole,  so  fre- 
quently, that  there  can  be  no  doubt  on  this  point ;  and  it  is  even  not  rare  for 
a  corpuscle  to  slip  out  from  the  anal  orifice  during  the  diastole, — that  is  to 
say,  at  the  very  time  when,  according  to  Schmidt,  the  fluid  should  flow  in 
from  the  outside.     I  found  the  Bursaria  just  named  during  spring  and  sum- 
mer in  standing  water  near  Tempelhof ;  it  agrees  in  the  main  with  Ehren- 
berg's  Bursaria   Vorticella.     The  buccal  orifice  is  situated  as  in  Bursaria 
truncatella,  in  which,  however,  I  did  not  observe  any  contractile  vesicle  at 
the  posterior  end  of  the  body.     The  specimens  of  B.  truncatella  I  observed 
were  aU  about  ^  of  a  line  or  more  long,  those  of  B.  Vorticella  at  most  ^ 
of  a  line.     The  latter  is  in  any  case  not  a  Leucophrys ;  therefore,  in  case 
Ehrenberg  considers  his  Bursaria  Vorticella  a  Leucophrys,  it  is  a  different 
animalcule  from  the  latter.     I  was  equally  unable  to  satisfy  myself  of  the 
correctness  of  Schmidt's  view  in  the  Paramecia.     When  a  specimen  of  Para- 
mecium Aurelia  lies  so  that  the  contractile  vesicle,  either  the  anterior  or  pos- 
terior, is  seen  at  the  margin,  it  appears,  under  certain  circumstances,  as  though 
a  short  canal  ran  directly  out  through  the  integument  of  the  animalcule ; 
but  in  reality  it  only  runs  into  the  integument,  and  tiu^ns  round  toward  the 
side  of  the  body  directed  away  from  the  eye  :  I  found  the  same  in  Parame- 
cium Chrysalis  also  :  it  was  always  one  of  the  rays  of  the  contractile  vesicle 
which  presented  to  Schmidt  the  appearance  of  an  external  oiifice.    The  same 


326  GENERAL  HISTOEY  OF  THE  INFUSOEIA. 

is  the  case  in  Bursariaflava,  where  I  could  always  trace  the  curvature  of  the 
vessel  toward  the  opposite  side  of  the  body  most  distinctly.  F.  Stein  strongly 
questions  the  external  opening  of  the  contractile  vesicle  in  the  Vorticellce. 
Hence  it  is  clear  that  the  explanation  of  the  contractile  vesicles  as  part  of  a 
water-vascular  system  is  unproven. 

"  Is  it,  however,  established,  on  the  other  hand,  that  the  contractile  reser- 
voirs pour  back  their  contents  again  into  the  parenchyma  whence  they  re- 
ceive it,  as  Yon  Siebold  says  ?  And  if  this  is  the  case,  how  does  it  happen  ? 
Everything  indicates  most  strongly  that  the  contractile  vesicles  are  filled  out 
of  the  vessels  during  the  diastole.  We  see  how,  during  this  process,  the 
swollen  part  of  the  vessels  near  their  embouchure  gradually  or  suddenly  re- 
turns to  its  smallest  diameter  as  the  stellate  figure  vanishes ;  and  I  have 
observed  a  part  of  a  vessel  inflated  with  the  fluid,  originating  at  the  extreme 
end  of  the  animalcule,  traverse  the  whole  distance  up  to  the  contractile  vesi- 
cle diuing  a  single  diastole.  This  phenomenon  may  be  supposed  to  show  that 
the  absorbed  fluid  which  had  inflated  the  vessel  into  a  globule,  flowed  during 
the  said  period  into  the  contractile  reservoir. 

"  But  if  there  is  a  fair  presumption  that  the  contractile  vesicles  are  filled 
out  of  the  vessels,  the  above  observations  teach  us  nothing  whatever  on  the 
question  as  to  where  the  fluid  flows  duiing  the  systole. 

"  I  have  hitherto  only  become  acquainted  Tvith  one  fact  relating  to  this  point. 
In  Bursaria  Vorticella  we  may  detect  the  following  fact :  as  soon  as  the  con- 
tractile vesicle  which  lies  at  the  posterior  end  of  the  body  has  contracted,  we 
may  observe  at  the  margins  of  the  animalcule,  in  its  usual  position  of  swim- 
ming, that  two  long  narrow  cavities  originate,  filled  with  transparent  coloiu'- 
less  fluid  ;  and  these  stretch  from  opposite  the  mouth  as  far  as  the  region  of 
the  contractile  vesicle.  They  both  gradually  enlarge,  and  thus  approach  near 
to  the  anal  point ;  here  they  meet,  lose  their  often  very  irregular  form,  and 
change  into  the  globular :  the  remaiaing  contents  of  the  body  are  displaced 
upwards  by  this ;  and  then  these  globular  reservoirs  contract  until  they 
vanish,  without  it  being  perceptible  where  the  fluid  has  been  driven  to ;  after 
some  time  the  narrow  light  streaks  reappear,  and  the  process  is  repeated 
in  the  way  above  described.  The  afferent  canals,  therefore,  are  not  filled 
at  the  commencement  of  the  systole ;  but  must  this  not  be  so  much  the 
more  expected  if  the  fluid  flowed  back  in  the  same  path  as  it  came  in,  the 
vanishing  of  the  contractile  vesicle  taking  place  much  more  rapidly  than 
its  production  ? 

"  I  have  never  yet  found  in  any  Infusorium  special  canals  in  which  the 
fluid  is  seen  to  flow  back  into  the  body  during  the  systole,  and  which  would 
give  the  means  of  a  perfect  ciixulation." 

Nucleus.  Nucleolus. — A  most  important  internal  organ  remains  for 
description,  viz.  the  nucleus.  This  name,  if  not  accurate,  is  convenient  to  de- 
signate the  structiu'e  in  question :  it  took  its  rise  in  the  hypothesis  of  the 
unicellular  nature  of  the  Ciliata,  and  has  ever  since  replaced  the  name 
"  testis,"  or  male  spermatic  gland,  assigned  it  by  Ehrenberg  on  the  sup- 
position of  its  being  the  male  reproductive  organ  in  these  presumed  herma- 
phrodite beings.  Indeed,  when  viewed  as  the  centre  of  reproductive  activity, 
or,  in  Prof.  Owen's  phraseology,  the  seat  of  the  '  spermatic  force,'  the  Berlin 
naturalist's  name  for  it  does  not  appear  so  inappropriate  ;  nevertheless  no  real 
homology  can  be  said  to  exist  between  the  testis  of  higher  animals  and  this 
body,  which,  on  the  contrary,  has  several  points  of  analogy,  at  least,  with  the 
nucleus  of  plant-cells  ;  nor  can  a  hermaphrodite  nature  be  rightly  ascribed  to 
the  Ciliata. 

The  nucleus  is  present  in  all  the  Ciliata,  and  is  mostly  very  readily  seen. 


OF  THE  PROTOZOA. CILIATA.  327 

unless  the  body  is  much  occupied  by  food  and  opaque  particles  of  any  kind. 
If  not  at  once  apparent,  it  is  demonstrable  by  the  disniption  of  the  body  by 
pressui'e  ;  by  the  process  of  diffluence,  which  disperses  the  surrounding  tissues ; 
or  by  the  addition  of  acetic  acid,  which  dissolves  the  rest  of  the  animal, 
leaving  the  nucleus  more  or  less  completely  isolated. 

It  occurs  as  a  well-defined,  finely-granular,  more  or  less  opaque  body, 
having  a  more  solid  look  than  the  surrounding  parts,  and  frequently  also 
a  tawy  or  sHght  yellow  blush  (XXIX.  28  c,  30  c,  48  c;  XXX.  1,  11  d, 
12  h,  27/).  It  varies  both  in  position  and  shape  in  different  species,  and 
either  presents  one  or  more  internal  spots  or  small  bodies  of  a  circular  outline 
which  represent  the  nucleolus  or  nucleoli,  or  this  organ  may  appear  as  a 
distinct  appendage  to  it  (XXVIII.  9-15 ;  XXIX.  28).  The  nucleus  is  im- 
bedded in  or  closely  united  with  the  cortical  lamina ;  and  although  it  may  be 
thrust  aside  by  the  impetus  of  passing  particles  of  food,  it  retains  its  hold. 
Under  the  usual  point  of  view  of  an  animalcule,  its  position  will  look  more 
central  than  it  really  is ;  for  it  is  either  in  advance  or  in  rear  of  the  real 
centre,  or  to  one  side  or  other  of  it,  and  often  lies  across  the  ahmentary  tube 
when  elongated  or  band-like.  But  what  is  curious  about  this  organ  is,  that 
it  is  not  at  all  firmly  fixed  in  its  position,  but  is  pushed  forward  or  backward 
to  one  side  and  to  the  other  by  the  movements  of  the  animal,  particularly  by 
those  of  the  retractile  ciliary  wreath,  and  also  by  the  ingestion  of  food.  This 
may  be  witnessed  in  Opercularia  and  Eplstylis.  Lastly,  even  in  examples  of 
the  same  species  its  position  is  not  constant. 

The  usual  figure  of  the  nucleus  is  circular  or  oblong,  but  it  may  be  clavate  or 
reniform,  or  sinuous  and  band-like.  The  first  type  of  outline  prevails  in  Para- 
mecium (XXIX.  28),  Colpoda  (XXIX.  37),  Nassida  (XXVIII.  1),  Chilodon 
(XXIX.  48),  Spirochona  (XXX.  17),  and  Stylont/chia  (XXVIII.  10  d).  A 
reniform  or  kidney-shaped  one  is  seen  in  Epistylis  plicatdis,  in  Opercrdaria 
articidata  (XXX.  1),  and  in  0.  berberina  ;  a  horse-shoe  figure  in  Vorticella  and 
Zoothamnimn ;  whilst  in  Epistylis  brancMophila,  in  Ophrydium  (XXX.  5,  6), 
Carchesium,  Trichodina  (XXIX.  16,  17),  Lagenophrys  (XXX.  29,  30),  &c. 
it  is  still  more  elongated  and  band-like  and  much  curved,  or  actually  sinuous. 
Cohn  represents  it  as  having  a  thick  clavate  figure  in  Nassida  elegans.  The 
figui^e,  moreover,  is  very  much  modified  during  the  reproductive  processes, 
and  in  the  metamorphoses  which  befall  some  at  least  of  the  Ciliated  Protozoa ; 
these  modifications,  however,  we  shall  not  here  consider,  but  reserve  them  to 
the  details  on  development.  Again,  even  among  examples  of  the  same  species, 
sHght  variations  occiu'  in  length  and  width,  and  in  curvature  or  sinuosity, 
where  no  reproductive  act  is  discernibly  in  progress.  Lastly,  not  a  few  of 
the  nuclei,  which  are  at  first  sight  simply  oblong,  are,  on  closer  examination, 
seen  to  have  a  depression  or  sulcus  on  one  side,  and  consequently  to  be,  strictly 
speaking,  bean-  or  kidney-shaped.  This  is  exemplified  in  the  nuclei  of  Para- 
mecium, certain  Nassulce,  and  in  Prorodon. 

Where  the  nucleus  is  elongated,  it  is  a  common  event  to  see  it  bent  par- 
tially round  the  pharynx  or  the  oesophagus,  at  some  little  distance  from  it. 

The  nucleus  being  the  last  of  the  soft  contents  to  break  up  after  death, 
is  presumably  of  a  more  solid  texture.  Its  tissue  may  be  described  as 
normally  homogeneous  ;  but  various  changes  are  ever  occurring  in  it,  render- 
ing it  at  one  time  more  transparent,  at  another  more  granular  and  opaque. 
It  must  owe  a  certain  degree  of  resistance  to  external  injuries  to  the  fact 
that  it  is  enclosed  by  a  tough  elastic  membrane  or  sac,  which  sometimes  is 
separated  from  it  by  a  clear  interspace  or  areola,  but  at  other  times  is  closely 
adherent,  and  only  demonstrable  by  artificial  means,  such  as  the  aj^plication 
of  chemical  reagents,  or  of  a  solution  of  potash,   or  of  acetic  acid:    this 


328  GENERAL  HISTORY  OF  THE  INFUSORIA. 

happens  in  Vaginicola.  When  loose,  this  membrane  not  imfrequently  falls 
into  plaits  or  folds.  It  is  represented  in  Cohn's  figure  of  the  nucleus  of 
Nassula  elegans  as  a  very  distinct  and  stout  tunic. 

The  rule  is,  that  the  nucleus  is  single,  and  it  has  been  assumed  as  a  fact 
that  the  appearance  of  a  double  nucleus  or  of  two  nuclei  is  a  general  indica- 
tion of  the  approaching  or  progressive  act  of  fission.  However,  Stein  in  a 
recent  figui'e  of  Stylonychia  mijtilus  (XVIII.  10),  delineated  in  Carus's  Icones 
Zootomicce,  represents  two  ovoid  nuclei  as  present  without  the  accompanying 
process  of  self- division.  In  CMlodon  Cucullulus,  he  also  represents  the 
nucleus  (XXX.  48  e)  to  be  composed  of  a  moderately  thick  external  or  cor- 
tical portion  siuTounding  a  clear  cavity,  in  the  centre  of  which  the  opaque 
solid  nucleolus  is  placed.  The  cortical  lamina,  he  affirms,  consists  of  the  usual 
homogeneous  granular  substance  which  makes  up  the  mass  of  most  nuclei, 
but  rather  firmer;  and  its  internal  free  surface  towards  the  cavity  is,  he 
says,  undulated  or  dentated.  The  interspace  between  the  nuclear  lamina 
and  the  nucleolus  is  not  always  clear,  but  occasionally  occupied  by  a  cloudy, 
finely-granular  matter, — w^hence  the  nucleus  acquires  rather  the  characters  of 
a  homogeneous  tissue,  having  a  central,  well-defined  nucleolus.  Although 
the  last-named  structure  is  probably  never  absent,  it  has  nevertheless  escaped 
Stein's  notice  in  very  young  specimens.  The  nucleus  of  Sjjirochona  in  young 
specimens  is  either  solid  and  homogeneous,  or  transversely  divided  into  tw^o 
by  a  crescentic  space  (XXX.  28/)  ;  the  nucleolus  occupies  the  middle  of  the 
nuclear  cavity,  and  has  around  it  a  finely-dotted  areola  (XXX.  17). 

In  the  case  of  Paramecium  both  Cohn  and  Stein  describe  the  nucleolus  to 
be  included  in  a  depression  or  hilum  on  one  side  the  nucleus.  Like  the 
nucleus  it  is  formed  of  a  membranous  coat  and  homogeneous  contents  (XXIX. 
28  d) ;  the  connexion  between  the  two  appears  to  be  only  by  the  adhesion  of 
their  membranes,  an  adhesion  readily  broken  through  by  pressure  or  by  the 
action  of  acetic  acid.  Further,  in  the  long  band-hke  nuclei,  the  nucleoli 
seem  to  be  multiplied  in  number. 

On  the  subject  of  its  chemical  nature.  Stein  concludes  from  the  reaction  of 
tincture  of  iodine,  and  of  acetic  acid  ^^ith  a  solution  of  sugar,  that  the  nucleus 
is  a  proteine  compound,  like  the  other  contents,  except  the  fat-corpuscles. 

Although  its  office  in  secreting  a  spermatic  fluid  may  be  justly  called  in 
question  (direct  obsei'vation  being  contrary  to  it),  yet  this  so-called  testis,  or, 
perhaps  more  correctly,  this  nucleus,  certainly  plays  a  most  important  part 
in  the  well-observed  mode  of  propagation  by  spontaneous  fission ;  for  whenever 
fission,  whether  longitudinal  or  transverse,  is  about  to  occur  in  an  animalcule, 
the  fii^st  change  observed  is  a  progressive  constriction  of  the  nucleus,  suc- 
ceeded by  that  of  the  body  generally.  This  constriction  goes  on  till  division 
is  complete,  each  segment  of  the  body  being  consequently  provided  Avith  a 
nucleus.  The  division  of  the  nucleus,  as  an  essential  element  in  the  process 
of  spontaneous  fission,  may  be  well  observed  in  the  transverse  division  of 
Paramecimn,  Bursaria,  or  Chilodon. 

Professor  Owen,  in  his  learned  and  able  Essay  on  Parthenogenesis,  refers 
to  the  initiative,  assumed  by  the  nucleus  of  Infusoria,  in  their  rej)roduction 
by  spontaneous  fission,  between  which  and  the  essential  contact  of  the  sper- 
matozoon with  the  germ -cell,  as  a  prehminary  to  the  primary  process  of 
self-division  of  the  latter,  in  the  course  of  the  development  of  more  perfect 
animals,  he  indicates  an  analogy ;  and,  after  having  completed  the  comparison 
of  the  results  in  the  two  cases,  goes  on  to  say, — "  This  is  certain,  that  the 
analogy  between  these  phenomena  in  the  midtiplication  of  the  parts  of  the 
germ-mass,  and  those  of  the  nucleus  in  the  multiplication  of  monads,  is  so 
close,  that  one   cannot   reasonably  suppose   that  the  nature  and  properties 


OF  THE  PEOTOZOA. CILIATA.  329 

of  the  nucleus  of  the  impregnated  germ-cell,  and  that  of  the  monad  can  be 
diiferent. 

''  Therefore,  I  infer,  that  the  nucleus  of  the  Polygastric  animalcules  is  the 
seat  of  the  spermatic  force  ;  it  can  only  be  called  testis,  figuratively,  it  is  the 
essence  of  the  testis.  It  is  the  force  which  governs  the  act  of  propagation  by 
spontaneous  fission :  and,  if  Ehrenberg  be  correct,  in  viewing  the  interstitial 
corpuscles  as  germ- cells  (to  which  opinion  Professor  Owen  inclines),  these 
essential  parts  of  ova  may  receive  the  essential  matter  of  the  sperm  from  the 
nucleus,  which  is  discharged  along  with  them  in  the  breaking  up  of  the 
monad,  which  Ehrenberg  regards  as  equivalent  to  an  act  of  oviposition  ;  and 
impregnated  germ- cells  may  thus  be  prepared  to  diffuse  through  space,  and 
carry  the  species  of  Polygastric  animalcules  to  a  distance  from  the  scene  of 
Hfe  of  the  parent  "  (p.  67,  Ed.  1849.) 

Lieberkiihn  {A.  N.  H.  xviii.  1856,  p.  321)  makes  the  nucleolus  of  import- 
ance in  founding  specific  characters.  He  says,  that,  excepting  the  eye-point, 
the  nucleolus  is  properly  the  only  part  which  distinguishes  Oplirijoglena 
flavkans  from  Bursaria  Jiava. — "This  body,"  he  proceeds  to  say,  "is  shaped 
Hke  a  grain  of  barley,  and  is  marked  at  each  end  with  a  few  sharply-defined 
streaks  or  fiuTows  ;  its  length  is  somewhat  more  than  -^  of  a  millimetre, 
its  thickness  in  the  middle  about  y^^  of  a  millimetre.  Its  substance  has  a 
stronger  refractive  power  than  that  of  the  rest  of  the  body,  but  far  less  than 
the  fat-hke  globules.  Under  the  highest  magnifying  power,  no  structure 
could  be  distinguished,  and  it  withstands  for  a  considerable  time  the  action 
of  water.  The  nucleolus  is  situated  on  the  middle  of  the  nucleus,  which  is 
about  one-fifth  of  the  entire  length  of  the  animalcule,  and  its  breadth  in  the 
middle  about  one-third  of  its  length ....  It  is  of  ovate  form ;  its  substance 
displays  no  recognizable  structure. 

"  The  nucleolus  has  very  difi'erent  characters  in  all  the  specimens  of  Bur- 
saria flava  I  have  hitherto  observed.  It  was  always  so  small  that  it  was 
difiicult  to  find  it,  and  never  became  visible  until  the  Infusorium  was  com- 
pressed, while  in  Ophryoglena  flava  it  may  usually  be  seen  through  the 
integuments.  Its  form  is  globular,  and  it  presents  no  structure.  It  gene- 
rally adheres  firmly  to  the  surface  of  the  ovate  nucleus." 

The  same  lesson  concerning  the  utility  of  the  nucleus  and  nucleolus  in 
distinguishing  genera  and  species,  might  be  gathered  from  the  descriptions 
of  Stein  and  others,  which  show  clearly  enough  that  these  organs  have  a 
detenninate  figure  and  relation  in  several  genera,  as,  for  example,  in  Spiro- 
chona  and  Paramecium. 

The  figure  of  the  nucleus  and  the  relation  of  the  nucleolus  to  it,  in  Pro- 
rodon  teres  and  in  Nassula  elegans,  are  deserving  attention.  In  the  former 
species  the  nucleus  is  represented  as  globular,  with  a  nucleolus  siu^mounting 
it  (XXVIII.  9) ;  in  the  latter,  the  nucleus  is  stoutly  clavate,  and  terminated 
by  a  small  oblong  nucleolus  at  its  narrower  extremity.  These  weU-marked 
peculiarities  in  the  two  examples  named,  coupled  with  the  views  of  Lieber- 
kiihn just  cited,  and  the  conclusions  of  Stein  and  Balbiani  concerning  the 
physiological  relations  of  the  two  organs  in  question,  wiU  challenge  for  them 
much  more  attention  than  they  have  hitherto  received. 

M.  Balbiani  has  lately  contributed  to  the  French  Academy  two  most  im- 
portant papers,  in  which  he  has  endeavoui^ed  to  demonstrate  a  sexual  repro- 
duction of  the  Ciliata,  the  nucleus  representing  the  female,  and  the  nucleolus 
the  male,  element.  In  his  fii-st  essay  he  illustrates  his  hypothesis  by  reference 
to  Paramecium  Bursaria  {A.  N.  H.  1858,  i.  p.  435),  and  thus  writes : — 

"  For  several  generations  the  Paramecia  multiply  by  spontaneous  scission, 
each  of  the  two  new  individuals  obtaining  half  the  primitive  nucleus .  .  .  .' 


330  GENEBAL  HISTOEY  OF  THE  INFUSORIA. 

But  under  the  influence  of  conditions  of  which  we  are  still  ignorant,  the 
species  propagates  itself  in  a  very  different  manner,  and  in  the  midst  of  phe- 
nomena far  more  complex  than  those  which  preside  over  the  multiplication 
by  fissiparity.  In  this  new  mode  we  shall  see  the  actual  anatomical  signifi- 
cation of  the  nucleus  and  nucleolus,  the  ftmction  of  which,  if  we  except  the 
di\ision  of  the  former  of  these  two  organs  in  the  act  of  spontaneous  division, 
has  hitherto  been  perfectly  passive.  It  is,  in  fact,  at  their  expense  that  the 
male  and  female  reproductive  elements  which  characterize  this  mode  of 
propagation  are  formed. 

"  When  the  period  arrives  at  which  the  Paramecia  are  to  propagate  with 
concourse  of  the  sexes,  they  are  seen  assembling  upon  certain  parts  of  the 
vessel,  either  towards  the  bottom,  or  on  the  walls.  The  copulation  is  always 
preceded  by  certain  preliminaries  which  are  very  cimous  to  observe,  but  upon' 
which  we  cannot  dweU  here.  Soon  they  are  found  coupled  in  pairs,  adherent 
laterally  and  as  it  were  locked  together,  with  the  similar  extremities  turned 
in  the  same  direction,  and  the  two  mouths  closely  applied  to  each  other.  In 
this  state  the  two  conjugated  individuals  continue  moving  with  agility  in  the 
liquid,  and  turning  constantly  round  theii'  axis.  There  is  nothing,  before  the 
copulation,  to  announce  the  considerable  changes  which  are  about  to  take 
place  in  the  nucleus,  and  the  nucleolus  which  accompanies  it.  It  is  diuring 
the  copulation  itself,  of  which  the  duration  is  prolonged  for  five  or  six  days  or 
more,  that  their  transformation  into  sexual  reproductive  apparatus  takes  place. 
"  The  nucleolus  has  undergone  a  considerable  increase  in  size,  and  has 
become  converted  into  a  sort  of  capsule  of  an  oval  form,  of  which  the  sm^face 
presents  longitudinal  and  parallel  lines  or  streaks.  Nearly  always,  it  soon 
divides  in  the  direction  of  its  greater  axis,  into  two,  or  more  frequently  into 
foui',  parts,  which  continue  increasing  independently  of  each  other,  and  in  a 
very  irregular  manner,  and  form  so  many  secondaiy  sacs  or  capsules.  At  a 
period  which  is  still  near  that  of  division,  these  latter  appear  to  be  composed 
of  an  extremely  fine  membrane,  enveloping  a  bundle  of  small,  curved  baciUa, 
extending  from  one  extremity  of  the  sac  to  the  other,  inflated  towards  the 
middle,  narrowed  towards  the  extremities.  It  is  these  which,  when  seen 
through  the  enveloping  membrane,  give  the  capsule  the  striated  a23pearance 
which  is  chai'acteristic  of  it,  and  which  even  exists  in  the  nucleolus  at  almost 
all  the  other  periods  of  the  life  of  the  Infusorium.  It  also  contains  a  perfectly 
colourless  and  homogeneous  fluid. 

'^  At  the  same  time  the  nucleus  has  also  changed  its  form  and  aspect ;  it 
has  become  rounded  and  widened  ;  its  substance  has  become  softer  and  lost 
its  refractive  power,  and  towards  its  margins  it  presents  notches,  which, 
penetrating  more  and  more  deeply  into  its  mass,  isolate  one  or  more  frag- 
ments, in  which  a  sufficient  magnifying  power  enables  us  to  see  a  certain 
number  of  small  transparent  spheres  with  an  obsciu'e  central  point.  In  other 
cases  the  nucleus,  whilst  still  almost  entire,  presents  this  aspect,  and  then 
appears  as  if  stuffed  \sith  these  little  rounded  bodies,  the  analogy  of  which  to 
o\TLles  cannot  be  doubted  in  the  least.  The  evolution  of  the  nucleus  and 
nucleolus  being  identical  and  progressing  at  the  same  rate  in  the  two  coupled 
indi^T-duals,  it  follows,  if  from  this  moment  we  regard  the  former  as  an  ovaiy, 
and  the  second  as  a  testicle  or  seminal  capsule,  not  only  that  each  of  them 
possesses  the  attributes  of  both  sexes,  but  that  they  fecundate  each  other, 
and  serve  at  the  same  time  as  male  and  female.  As  regards  this  fecimdation 
itseK,  everything  seems  to  prove  that  it  takes  place  by  means  of  an  exchange, 
,  made  by  the  two  coupled  individuals,  of  one  or  more  of  their  seminal  capsules, 
which  pass,  through  the  apertures  of  the  mouths  closely  applied  against  each 
other,  from  the  body  of  one  Paramecuim  into  that  of  the  other ;  for,  very 


OF  THE  PEOTOZOA. CILIATA.  331 

often,  although  we  may  not  be  able  to  perceive  this  passage  itself,  we  may 
at  least  detect  the  moment  when  one  of  the  capsules  already  engaged  in  one 
of  the  months,  is  on  the  point  of  clearing  this  aperture.  Does  the  exchange 
which  causes  fecundation  take  place  with  all  the  capsules  in  a  single  copula- 
tion, or  in  so  many  successive  copulations  with  different  individuals  ?  This 
is  a  question  the  solution  of  which  is  not  easy,  and  which,  to  keep  within  the 
field  of  our  observations,  we  shall  not  attempt  to  solve  at  present. 

"  However  this  may  be,  each  capsule,  after  its  transmission,  still  continues 
to  increase  in  size  in  the  body  of  the  individual  w^hich  has  received  it ;  for  we 
have  never  found  any  which  had  attained  the  limit  of  their  development  in 
individuals  which  were  still  coupled.  They  then  frequently  attain  a  volume 
greater  than  that  of  the  nucleus  itself;  but  there  is  never  more  than  one  that 
arrives  at  matimty  at  the  same  time.  When,  having  arrived  at  this  state, 
it  is  examined  after  being  pressed  out  of  the  body  of  the  animalcule  to  free 
it  fi'om  the  granulations  which  mask  it  more  or  less  while  there,  it  appears 
imder  the  form  of  a  large  ovoid  body,  the  surface  of  which  presents  a  multi- 
tude of  parallel  striae  dii^ected  longitudinally,  and  due  to  the  arrangement  in 
series  of  the  coi^uscles  contained  in  the  interior.  Compression,  carried  so  far 
as  to  cause  its  rupture,  distinctly  shows  it  to  be  formed  by  a  membrane  of 
extreme  tenuity,  and  contents,  enclosing  an  innumerable  quantity  of  small 
fiisifonn  corpuscles,  of  which  the  extremities  are  completely  lost  to  sight  in 
consequence  of  their  extreme  fineness.  As  soon  as  they  are  free,  these  little 
bodies  show  themselves  to  be  animated  by  a  vacillatory  and  translatory  move- 
ment, which  soon  causes  their  dispersion  in  the  cii^cumambient  fluid.  These 
are  the  spermatozoids  of  P.  Bursaria.  Iodine,  alcohol,  and  acetic  acid  instantly 
stop  their  movements  ;  they  are  insoluble  in  the  last-mentioned  reagent  when 
concentrated,  although  this  dissolves  all  the  other  elements  of  the  body,  with 
the  exception  of  the  green  granules. 

"  It  is  usually  from  the  fifth  to  the  sixth  day  following  the  copulation,  that 
the  fii'st  germs  are  seen  to  make  theii'  appearance,  in  the  form  of  small  rounded 
bodies,  formed  of  a  membrane  which  is  rendered  very  evident  by  acetic  acid, 
and  greyish,  pale,  homogeneous,  or  almost  imperceptibly  granular  contents, 
in  which  neither  nucleus  nor  contractile  vesicle  is  yet  to  be  distinguished. 
These  organs  do  not  appear  until  afterwards.  The  observations  of  Stein 
and  F.  Cohn  have  shown  how  these  embryos  quit  the  body  of  the  mother  in 
the  form  of  Acinetce  furnished  with  knobbed  tentacles — true  suckers,  by 
means  of  which  they  remain  for  some  time  still  adherent  to  the  mother, 
deriving  their  nourishment  from  her  substance  ;  but  theii'  investigations  did 
not  reveal  to  them  the  ultimate  fate  of  these  young  animalcules.  I  have 
been  able  to  follow  them  for  a  considerable  time  after  they  detached  them- 
selves from  the  body  of  the  mother,  and  have  con\-inced  myself  that,  after 
losing  their  suckers,  becoming  surrounded  mth  vibratile  cilia,  and  obtaining 
a  mouth  which  first  shows  itself  in  the  form  of  a  longitudinal  fiuTow,  they 
definitely  acquired  the  form  of  the  mother,  becoming  penetrated  in  the  same 
way  by  the  green  granulations  characteristic  of  this  Paramecium,  without 
undergoing  any  more  important  metamoqDhoses." 

At  the  time  this  first  record  of  his  observations  was  read,  M.  Balbiani  stated 
that  he  had  collected  them  from  the  investigation  of  six  or  seven  species,  but 
since  that  period  he  has  pui^sued  his  observations  in  several  other  species,  and 
completed  some  old  ones  previously  interrupted  from  want  of  materials 
{A.  N.  H.  1858,  ii.  p.  439).  In  his  latest  paper,  he  enunciates  the  remark- 
able statement  that  he  has  been  led  to  regard,  in  a  great  number  of  cases, 
what  nearly  all  authors  have  considered  to  be  a  spontaneous  division  in  a 
longitudinal  direction,  as  a  sexual  union  of  two  indi\iduals.     "  Very  often, 


332  GENERAL  HISTORY  OF  THE  INFUSORIA. 

in  fact,  I  have  been  able  to  ascertain  that  this  state  coincided  with  cer- 
tain remarkable  changes  which  took  place  in  the  internal  organs  of  these 
animals." 

The  following  is  the  general  summary  of  the  results  M.  Balbiani  has 
arrived  at : — "  I.  The  corpuscle  which,  in  the  Infusoria,  has  been  described 
under  the  name  of  nucleolus,  and  which  I  have  shown  to  be  the  male  genital 
gland,  has  hitherto  only  been  indicated  in  a  few  rare  species.  In  connexion 
with  this,  I  have  examined  a  great  number  of  individuals  belonging  to  numer- 
ous and  varied  forms,  and  I  have  convinced  myself  that,  far  from  constituting 
an  exception,  the  presence  of  one  or  even  several  nucleoles  was  a  nearly  con- 
stant fact  in  the  different  types  of  this  class  ;  but  frequently  the  simple  or 
multiple  nucleole  which  they  contain  is  so  intimately  confounded  with  the 
substance  of  the  nucleus,  that  it  only  becomes  apparent  when  it  is  separated 
therefrom  accidentally  by  the  action  of  reagents,  or  spontaneously  at  certain 
determinate  periods  in  the  life  of  these  creatures,  principally  at  the  time  of 
their  sexual  propagation.  I  have  counted  fourteen  species  in  which  this 
organ  was  very  evident  to  me,  and  in  which  I  have  also  been  able  to  follow 
its  evolution,  to  a  greater  or  less  extent,  at  the  breeding- season,  at  the  same 
time  that  I  was  an  eye-witness  of  the  other  actions  which  conciu"  in  assuiing 
the  reproduction  of  these  animalcules  by  fecundated  germs. 

"  As  regards  the  number  and  situation  of  the  testicular  organ  of  the  Infu- 
soria, I  have  met  with  the  following  varieties.  It  is  simple,  rounded,  and 
lodged  in  more  or  less  deep  depressions  of  the  nucleus  in  Paramecium  Aurelia 
and  P.  caudatum,  and  also  in  a  third  sj^ecies,  nearly  alhed  to  P.  Bursaria,  but 
smaller  and  destitute  of  green  granules.  The  genus  Bursaria  (B.  leucas, 
flava,  and  vernalis)  also  presents  a  simple  nucleole  situated  in  the  vicinity  of  the 
nucleus.  The  same  thing  occurs  in  Chilodon  Cucullulus.  But  with  regard  to  the 
latter,  I  must  remark  that  I  do  not  regard  as  the  analogue  of  the  nucleole  of  the 
preceding  species  the  corpuscle  to  which  M.  von  Siebold  has  given  this  name, 
and  which  is  placed  in  the  interior  of  the  granular  mass  of  the  nucleus,  in 
the  centre  of  a  broad  transparent  zone.  The  true  nucleole  or  testicle  of 
Chilodon  appears  in  the  form  of  a  small,  rounded,  brilliant  grain,  provided 
with  a  proper  membrane,  and  situated  quite  to  one  side  and  towards  the 
middle  of  the  nucleus.  It  is  very  easily  perceived  in  large  specimens  by 
employing  the  action  of  reagents.  As  regards  the  nucleus  and  its  internal 
parts,  I  make  no  difficulty  in  regarding  them  as  representing  all  the  elements 
of  an  ovum,  of  which  the  nucleole  of  the  celebrated  German  naturalist  would 
be  nothing  but  the  germinal  spot.  The  disappearance  of  the  clear  zone  and 
of  its  central  corpuscle  in  the  animals  which  have  just  copulated,  especially 
appears  to  me  to  militate  in  favour  of  this  view. 

"  II.  I  have  met  with  a  multiple  testicle  in  many  species  belonging  to  the 
groups  of  the  Oxt/trichince  and  of  the  Euplotes  or  PJoesconice,  including  the 
highest  types  of  this  class.  In  the  genus  Oxytricha  the  two  nuclei,  which 
are  elongated  in  the  direction  of  the  greater  axis  of  the  body,  are  each  accom- 
panied by  a  small,  rounded,  testicular  body,  very  distinct  from  the  correspond- 
ing nucleus.  There  are  also  two,  placed  one  to  the  right  and  the  other  to 
the  left  of  the  long  nucleus,  which  is  curved  into  the  form  of  a  horse-shoe, 
in  Euplotes  Charon  and  E.  viridis.  In  the  genera  Stylonychia  (S.  Mytilus, 
pustulata,  and  lanceolata)  and  Urostyla  {U.  grandis)  the  nucleoles,  to  the 
number  of  four  or  five,  are  distributed  in  two  groups  in  the  vicinity  of  the 
nuclei,  of  which  the  anterior  is  accompanied  by  two,  and  the  posterior  also 
by  two  or  sometimes  three,  of  these  little  organs.  They  are  remarkable  from 
their  distinctly-rounded  outhne,  their  great  refractive  power,  and  their 
homogeneous  structure.     In  Spirostoynmn  amhiguum,  each  of  the  grains   of 


OF  THE  PROTOZOA. CILIATA.  333 

the  long  moiiiliform  cord  which  here  replaces  the  oval  nucleus  of  the  other 
species,  gives  lodgment,  in  a  deep  depression  of  its  surface,  to  a  small  rounded 
corpuscle,  which  corresponds  with  the  nucleole  of  the  preceding  species  ;  this 
brings  the  number  of  testicles  in  this  animal  to  forty-five  or  fifty.  I  have 
only  been  able  to  perceive  them  in  individuals  which  have  been  copulating 
for  a  certain  time,  and  by  employing  dilute  acetic  acid.  It  is  very  probable 
that  an  analogous  arrangement  will  be  found  in  the  other  types,  in  which  the 
nucleus  is  formed  of  grains  placed  in  a  single  row,  like  a  necklace,  such  as 
Stentor,  Kondylostommn,  Traclielius  moniliger,  &c. 

''  III.  The  evolution  of  the  male  genital  apparatus  of  the  Infusoria,  as  just 
characterized,  in  the  other  species  of  the  genus  Paramecium  does  not  differ 
from  that  presented  to  us  by  P.  Bursaria.  In  the  Oxytricliina  each  of  these 
organs  remains  entii'e,  becomes  enlarged,  and  exhibits  in  its  interior,  applied 
against  its  wall,  a  thick  granular  body,  furnished  with  a  tubular  appendage, 
which  projects  into  the  cavity  of  the  capsule,  and  appears  to  be  open  at  its 
free  extremity.  This  tube,  which  seems  to  be  an  excretory  duct,  often 
appeared  to  be  filled  with  capillary  filaments  of  extreme  fineness,  arranged 
parallel  to  the  axis  of  the  duct  in  question,  in  which  they  were  fixed  by  a 
portion  of  their  length,  whilst  the  remainder,  escaping  by  the  orifice  of  the 
tube,  radiated  in  aU  directions  in  the  interior  of  the  capsule.  Subsequently 
the  granular  body  and  its  duct  disappear,  and  the  filaments,"  becoming  free, 
coUect  into  a  bundle,  which  fills  the  whole  of  the  formative  sac.  Although 
I  have  never  seen  them  execute  any  movements,  I  do  not  hesitate  in  consi- 
dering them  as  the  spermatic  filaments  of  these  animals. 

"  IV.  It  is  with  equal  certainty  that  we  may  call  the  nucleus  the  female 
genital  organ  of  the  Infusoria,  in  opposition  to  the  perfectly  hypothetical 
assertion  of  Ehrenberg,  who  regards  it  as  the  testicle.  Its  evolution  likewise 
only  commences  at  the  time  of  reproduction,  and  often  during  the  sexual 
union  itself.  In  P.  Aurelia  and  P.  caudatum,  towards  the  end  of  the  copulation, 
its  surface  is  traversed  in  aU  directions  by  numerous  ftuTows,  which,  penetrat- 
ing deeper  and  deeper  into  its  mass,  finally  divide  it  into  a  great  number  of 
unequal  and  irregularly-rounded  fragments,  having  a  clear  centre  more  or 
less  surroimded  by  granules.  I  should  compare  these  with  the  first  rudi- 
ment of  a  vitellus,  and  the  transparent  central  portion  to  a  more  or 
less  developed  germinal  vesicle.  The  fragments  thus  formed  are  soon  dis- 
persed in  the  siuTounding  parenchyma.  Here  a  very  small  number  of  them, 
almost  always  foiu-,  never  more  and  very  rarely  less,  complete  their  evolution, 
and  soon  acquii-e  the  appearance  of  complete  and  well- developed  ova.  In 
this  state  they  present  themselves  in  the  form  of  small  brilliant  bodies,  per- 
fectly equal  in  volume,  slightly  oval,  and  of  a  bluish-grey  appearance.  We 
may  very  clearly  distinguish  in  them  a  finely- granular  vitellus,  surroimded 
by  its  proper  membrane,  which  separates  from  it  more  or  less  after  a  few 
moments'  exposure  to  water.  The  germinal  vesicle  and  spot  are  also  visible 
with  a  distinctness  truly  surprising,  considering  that  we  have  to  do  here  with 
the  smallest  of  living  organisms.  I  have  met  with  these  ova  still  enclosed  in 
the  body  of  the  animal  on  the  seventh  day  after  the  copulation :  they  no 
longer  exhibited  either  germinal  vesicle  or  spot ;  and  their  volume  had  slightly 
increased.  In  the  allied  species,  P.  Bursaria,  the  reniform  nucleus  becomes 
unrolled  before  breaking  up,  and  in  this  state  resembles  the  ribbon-shaped 
nucleus  of  the  Vorticellce.  About  twenty  or  twenty-five  of  the  fragments 
produced  from  it  continue  their  development  and  become  so  many  perfect 
ova.  In  the  nucleus  of  Chilodon  Cucullidus,  also,  we  observe,  after  the  copu- 
lation, the  disappearance  of  the  transparent  zone  with  its  central  obscure 
spot.     In  the  genera  Stylonychia  and  Urostyla  the  ova  are  four  in  number. 


334  GENERAL  HISTORY  OF  THE  INFUSORIA. 

as  in  Paramecium  caudatum,  but  they  are  produced  by  a  different  mechanism. 
Each  of  the  two  nuclei  divides  into  two  halves,  as  in  the  act  of  spontaneous 
division ;  and  the  four  fragments  thus  produced  form  an  equal  number  of 
perfect  ova.  Lastly,  in  Sjjirostomum  amhigimm,  we  have  seen,  in  individuals 
which  have  been  copulating  for  some  time,  the  forty  or  fifty  grains  of  the 
long  flexuous  cord  which  traverses  the  body  become  rounded  and  detached 
from  each  other.  But  we  have  been  unable  to  discover  in  these  all  the 
characters  of  an  ovum  with  the  same  distinctness  as  in  the  preceding  species, 
no  doubt  because  they  had  not  yet  arrived  at  their  complete  development. 

"  Y.  I  have  not  witnessed  the  deposition  of  the  ova  in  these  animals.  It 
is  very  probable  that  they  escaped  by  the  anus,  or  by  some  neighbouiing 
apertiu'e.  Thus,  in  the  Stylonycliice,  I  have  seen  them  collect  in  the  posterior 
part  of  the  body,  which  bears  the  anal  orifice,  and  diminish  gradually  in  num- 
ber from  the  fii'st  or  second  day  after  the  copulation.  It  is  a  singular  thing, 
that  about  this  period  a  round  pale  body  begins  to  make  its  appearance  in  the 
centre  of  the  animal ;  this  becomes  constricted  about  the  middle,  and  recon- 
stitutes the  double  nucleus  of  Stylonycliia. 

^'  VI.  The  Infusoria  are  destitute  of  copulatory  organs.  In  most  cases  the 
copulation  is  effected  by  simple  juxtaposition,  the  two  mouths  establishing 
the  sexual  communication  {Paramecium,  Bursaria,  Euplotes,  Chilodon,  Sjjiro- 
stomum). In  the  Oxytrichina  the  union  is  more  intimate,  and  goes  so  far  as 
to  constitute  a  true  soldering  of  the  two  individuals  for  more  than  two-thirds 
of  their  anterior  part.  Any  one  who  had  not  witnessed  all  the  phases  of  this 
singular  copulation,  would  be  unable  to  avoid  regarding  this  state  as  a  longi- 
tudinal division,  proceeding  from  behind  forwards,  in  a  single  animal.  But, 
even  if  direct  observation  were  wanting,  the  concomitant  changes  of  the 
internal  organs,  which  are  so  characteristic,  cannot  leave  the  least  doubt  as 
to  the  actual  signification  of  this  act." 

Ovules. — In  Ehrenberg's  organology  of  Infusoria,  ovules  or  ova  assumed  a 
high  importance.  The  structures  he  so  designated  had  no  distinctive  featiu'es 
assigned  them,  whereby  they  could  be  distinguished  from  other  corpuscles 
and  granules  in  the  interior ;  and,  in  consequence,  theii'  existence  could  not 
be  confirmed  by  other  microscopists,  who  for  the  most  part  declared  that  the 
supposed  ova  were  indifferently  alimentary  vacuoles,  particles  of  food,  fat 
globules,  or  the  ordinary  granules  of  the  interior.  The  general  opinion  became 
pronounced  against  the  very  existence  of  ovules  and  of  development  by  their 
means,  whilst  the  deposition  of  ova,  which  Ehrenberg  believed  he  witnessed  in 
several  instances,  was  explained  to  be  an  act  of  diffluence  misconceived.  This 
explanation,  for  instance,  has  been  given  to  his  recorded  observation  and  his 
figures  of  the  act  of  oviposition  in  Colpoda  CucuUulus,  which  represented  this 
animalcule  as  bursting  and  giving  vent  to  strings  of  ova,  which  first  ran 
together  in  a  reticulate  manner,  and  then,  after  a  time,  became  individually 
developed  into  young  Colpodce.  According  to  the  opposite  view,  the  bursting 
and  extrusion  of  contents  are  no  other  than  the  phenomena  of  diffluence  and 
the  dispersion  of  particles  of  sarcode,  whilst  the  young  supposed  to  originate 
from  those  particles  are  merely  minute  Monads  or  monadiform  coi-puscles 
found  in  company  with  the  Colpodce. 

One  objection  brought  against  the  assumption  of  ova  being  ejected  from 
Protozoa  in  the  exercise  of  a  generative  function  is  certainly  frivolous — viz. 
that  the  empty  or  broken  shells  of  the  ova  ought  to  be  met  with  ;  for  the  shell 
of  an  e^g,  however  useful  in  larger  animals  as  a  defence  against  injuiy,  is  no 
essential  part  of  an  ovum  from  which  a  new  being  can  be  developed. 

Although  the  existence  of  ova  among  the  CiLiata  has  been  denied  by  the 
great  authorities  on  Infusoria — by  Kolliker,  8iebold,  Leuckart,  Cohn,  Stein, 


OF  THE  PEOTOZOA. CILIATA.  335 

Van  der  Hoe v  en  and  others,  yet  it  has  latterly  found  two  advocates  in  Prof* 
Perty  and  Mr.  Carter.  The  latter  writer  (A.  N.  H.  1856,  xviii.  p.  225)  can 
adduce  little  direct  e\^dence  to  support  his  views,  and  seems  to  rest  more 
weight  upon  argument  from  analogy  with  Amoehcea,  ArceWma,  Astasias,  and 
Euglence,  in  all  wliich  he  has  satisfied  his  own  mind  of  the  presence  of  ovules, 
and  of  their  development  in  the  two  latter  genera.  "The  same  kind  of  develop- 
ment," he  writes,  "  of  the  ovule  probably  takes  place  in  aU  the  Ehizopoda  as 
in  Sjjongilla  and  in  Astasia  and  Euglena :"  but  this  is  not  proving  that  Hhi- 
zopoda  are  developed  by  ova ;  and  the  entire  value  of  the  presumed  analogy 
^vith  Astasice  depends  on  our  admitting  a  natural  afiinity  and  close  similarity 
in  organization  between  that  family  and  Ciliated  Protozoa,  on  the  one  hand, 
and  Rhizopodous  Protozoa  on  the  other.  Indeed,  we  imagine  the  prevailing 
opinion  to  be,  that  the  histoiy  of  development  of  Asfasicea  corresponds  rather 
with  that  of  vegetable  organisms  than  with  that  of  the  Protozoa  ;  for  this  so- 
called  ovular  rej)roduction  of  the  Astasiwa  certainly  seems  analogous  with  the 
development  of  zoospores  in  many  unicellular  Algae. 

To  recur  to  Mr.  Carter's  statements,  he  tells  us  he  applies  the  term 
"  ovules  "  to  "  a  number  of  discoid  or  globular  nucleated  cells,  which  appear 
together  in  the  sarcode  of  some  of  the  Infusoria  ;  "  and  he  subsequently  pro- 
ceeds to  uphold  his  views  by  his  own  personal  observations,  and  by  inferences 
drawn  from  others.  "  In  many  of  Ehrenberg's  enterodelous  Infusoria  it  is 
not  uncommon  to  see  a  number  of  defined  globular  bodies,  of  nearly  equal 
size  and  of  a  faint  opaque  yellow  colour,  which  closely  resemble  ovules — 
e.  g.  Amjjhileptus  fasciola  (Ehr.),  Himantophorus  Charon  (Ehr.),  &c. ;  nor  is 
it  improbable  that  many  of  his  Trachehna,  which  come  near  Planaria,  possess 
ovules  similar  to  those  which  are  found  in  the  latter ;  but,  from  beuig  so  much 
mixed  up  with  the  spherical  cells,  pass  equally  unnoticed  while  in,  as  well  as 
when  out  of,  the  body,  under  such  circumstances.  M.  J.  Haime,  however,  has 
distinctly  seen  instances  in  wliich  these  bodies  have  been  ejected  from  Infusoria, 
and  have  passed  into  locomotive  animalcules  under  his  eye.  Thus  he  states 
that  in  Plcesconia  they  form  a  group  of  from  forty  to  fifty  in  the  middle  of 
the  body,  are  round,  issue  one  by  one,  remain  tranquil  some  time,  then  deve- 
lop two  filaments,  one  in  front,  the  other  behind,  and  move  about  rapidly. 
In  an  '  undescribed  '  species  of  Dileptus  they  are  whitish,  and  form  a  wreath 
extending  almost  throughout  the  whole  length  of  the  body,  become  yellow 
towards  the  anal  extremity,  where  they  pass  out  with  the  remains  of  the 
food,  soon  develope  two  opposite  filaments,  and  move  about  rapidly.  In 
Paramecium  Aurelia,  M.  Haime  states  that  an  ovary  appears  some  hours 
before  death,  about  the  middle  of  the  body,  which  becomes  filled  with  about 
sixty  little  nuclei :  these  increase  in  size,  burst  the  ovisac,  and  thus  pass  into 
the  body  of  the  parent,  from  which  they  finally  escape  by  an  opening  in  the 
tegumentary  covering,  formed  by  the  diffluence  of  the  latter ;  and  the  ovisac 
follows  them." 

Perty  has  used  great  diligence  in  searching  for  the  presence  of  ovules  or, 
more  accurately,  of  germs  (Blastien),  and  has  adduced  various  arguments  for 
their  existence.  He  states  {op.  cit.  p.  6Q)  that  their  aspect  is  distinctive, 
although  their  colour  varies  in  difiPerent  species,  that,  imlike  food,  they  re- 
tain their  form,  increasing  only  in  size,  and  that,  on  the  dissolution  or  breaking 
up  of  the  animalcules,  they  display  themselves  as  free  individualized  struc- 
tures. It  is  only,  he  adds,  in  incomplete  forms,  in  young  and  imperfect  beings, 
that  any  doubt  can  exist  respecting  the  character  of  these  corpuscles.  Ovular 
development  does  not  take  place  as  Dujardin  siu'mised,  by  detached  morsels 
of  the  sarcode,  nor  by  ova  such  as  Ehrenberg  supposed,  but  by  a  peculiar 
set  of  bodies,  originating  in  the  interior  of  the  animals,  and  progressively 


3l36  GENERAL  HTSTOEY  OF  THE  INFUSOEIA. 

multiplied.  Theii'  minuteness  is  a  bar  to  observation  ;  and  it  is  only  by  the 
concurrence  of  favourable  circumstances — by  the  presence  of  the  ovules  in 
their  first,  intermediate,  and  finished  stages — that  they  can  be  satisfactorily 
made  out,  as  in  Nassula  aurea,  Euglena  viridis,  CTionemonas  bicoJor,  &c. 
Fission  may  be  several  times  repeated  ;  but  the  formation  of  germs  takes  place 
at  the  expense  of  the  contents  of  the  parent. 

The  unusually  small  size  of  many  animalcules  is  another  argument  advanced 
in  favour  of  propagation  by  germs  or  ova,  since  the  act  of  fission  is  limited  to 
a  certain  size,  and  the  natural  characters  of  the  species  are  to  be  preserved. 
Thus  Pertymet  with  examples  of  Kerona  pustulata  as  small  as  1-70'",  which 
could  scarcely  originate  from  fission.  They  were  exactly  like  the  original 
animalcule  except  in  being  more  round.  Specimens  of  Pleuronema  crassum 
occur  no  larger  than  1-90'",  devoid  of  molecules,  more  transparent  and  slender 
than  old  ones,  with  a  more  pointed  apex,  but  otherwise  their  coimterpart. 
Again,  Nassula  aurea  varies  from  1-150'"  to  1-12'" ;  and  in  those  of  1-50'"  the 
rudiments  of  the  "  dental"  apparatus  are  distinguishable.  AiiAmpliileptus  mo- 
niliger,  1-6'",  having  a  very  short  neck,  was  distended  by  100-150  germs  or 
ovules  surrounded  by  some  thousands  of  fine  moL  ijules ;  that  these  were  neither 
vacuoles  nor  stomach-sacs  was  seen  at  places  where  they  displayed  themselves 
as  individualized  corpuscles.  Moreover  there  were  no  other  animalcules  or  par- 
ticles of  food  in  the  glass  containing  the  AmpMleptiis,  and  aU  the  germs  were 
uniform  in  size,  in  hue,  and  in  refractibihty,  and  readily  distinguishable  from 
some  swallowed  Infusoria  present  in  some  spots.  The  green  spheroidal  cor- 
puscles in  Paramecium  versutmn,  having  a  medium  size  of  1-450'",  are  true 
ovules:  they  do  not  change  colour,  like  the  green  nutritive  matters  of  Infusoiia, 
to  yeUow,  red,  or  brown  ;  and  when  the  animalcule  is  left  dry  by  evaporation, 
they  become  isolated.  Although  no  germinal  speck  is  discoverable  in  these 
bodies  as  in  ordinary  ovules,  yet  it  is  remarkable  that  a  fold,  streak,  or  darker 
space  is  visible.  Small  specimens  of  this  Infusorium  also  occur  in  wliich  the 
ovules  are  colourless  or  pale  green ;  and  on  one  occasion  Perty  saw,  amid  the 
fully- developed  individuals,  oval  greenish  animalcules  of  about  1-60'",  which 
seemed  no  other  than  the  escaped  germs  of  the  Paramecium. 

Such  are  some  of  the  principal  observations  Perty  appeals  to  in  order  to 
substantiate  his  hypothesis  of  internal  germs  and  of  development  from  them. 
He  has  given,  in  illustration,  a  number  of  figures  ;  but  they  are  too  rudely 
dra^\T:i  to  efficiently  answer  their  object ;  and  we  must  confess  our  inability  to 
receive  the  fact  of  the  existence  of  ova  or  germs  as  at  all  demonstrated  m  the 
CiHata  either  by  the  researches  of  Mr.  Carter  or  of  Perty.  The  discoid  or 
globular  nucleated  cells  which  the  first-named  writer  makes  out  so  clearly  in 
the  Astasicea,  are  merely  supposed  to  be  represented  by  certain  "  defined  glo- 
bular bodies  of  nearly  equal  size  and  of  a  faint  opaque  yeUow  colour^  which 
closely  resemble  ovules  "  (why  ?),  not  uncommon  in  many  ciliated  Protozoa, 
e.  g.  '^Amphileptus  fasciola,  Himantophorus  Charon,  &c."  Such  evidence  is 
purely  presumptive,  and  is  little  aided  by  M.  Jules  Haime's  anomalous  obser- 
vations. Respecting  Perty's  arguments  and  reported  phenomena,  it  may  be 
objected  that  he  does  not  estabLLshhis  attempted  rigorous  description  of  germs 
— does  not  show  their  distinctive  peculiarities  as  stated,  and  seems  to  have 
confounded  together  various  internal  bodies  in  his  description  of  germs.  Thus 
in  the  Paramecium  versutum  (which  he  presumes  to  be  the  same  animalcule 
described  by  Colin  as  Loxocles  Bursaiia)  the  green  spheroidal  corpuscles 
look  to  be  nothing  more  than  the  chlorophyll  globiiles  pointed  out  by 
Cohn  and  Stein.  Again,  of  the  ambiguous  corpuscles  in  other  Protozoa  cited 
as  ovules  or  germs,  it  is  simply  from  their  doubtful  character  that  this 
can  be  presumed  ;   for  our  knowledge  of  the  contents  of  the  Ciliata,  of  the 


I 


OF  THE  PROTOZOA. CILIATA.  337 

changes  they  may  visibly  undergo  from  the  action  of  external  agents,  from 
age,  and  other  conditions,  is  at  present  too  imperfect  to  signalize  certain  par- 
ticles, definable  by  no  sufficient  characteristics,  as  special  structures,  such  as 
ova, — unless,  indeed,  we  can  watch  their  origin,  growth,  extrusion,  and  de- 
velopment into  animalcules  assuming  the  particular  form  and  organization  of 
the  parent  animal  at  an  earlier  or  later  date.  Perty,  indeed,  has  imagined — not 
proved — certain  minute  organisms  floating  in  the  \icinity  of  an  animalcule, 
ha\'ing  about  the  same  size  as  the  supposed  internal  ovules,  to  be  the  young 
resulting  from  those  gemis  ;  and  although  it  cannot  be  denied  that  he  is  in 
the  nght,  yet  it  is  for  him  to  show  that  he  is  so,  by  elucidating  the  phases  of 
development ;  and  we  must  always  keep  in  view  the  very  erroneous  fancies 
which  result  from  these  supposed  relations  between  contiguous  organisms, 
very  probably  only  accidentally  brought  together, — of  which  we  have  an 
illustration  in  the  visionary  hypotheses  of  spontaneous  development  and 
ascendant  embryogeny  put  forth  by  Gros  and  others. 

^Ye  have  stated  the  preceding  objections  against  the  particular  statements 
of  Carter  and  Perty,  and  not  against  the  hypothesis  of  the  production  of  in- 
ternal germs  ;  for  sufficient  examples  are  on  record  of  the  production  of  such 
germs  and  of  living  embryos  within  animalcules,  after  preparatory  develop- 
mental changes,  from  the  fission  and  breaking  up  of  the  nucleus.  Before  leaving 
this  hypothesis  of  the  existence  and  development  of  internal  germs,  it  is  but 
right  to  mention  that  it  has  been  received,  among  others,  by  Eckhard  and  by 
Oscar  Schmidt,  both  of  them  supporters,  in  almost  all  their  details,  of  Ehren- 
berg's  \iews,  and  who  are  believed  by  most  authorities  to  have  too  much  the 
character  of  advocates  of  a  particular  theorj^,  to  discuss  or  to  observe  in  ge- 
neral without  prejudice.  To  allude  briefly  to  their  observations,  Eckhard 
(A.  N.  H.  1847,  xviii.  Suppl.  p.  446)  in  the  first  place  remarks,  as  others 
have  done,  on  the  very  difiPerent  sizes  of  animalcules  of  the  same  species,  as 
a  proof  of  ovular  development,  arguing  that  the  very  smallest  cannot  result 
from  fission  or  gemmation.  To  this  he  appends  an  observation  made  on 
Stentor  cceruleus  (XXIX.  8),  which,  from  its  completeness  and  apparent 
truthfulness,  deserves  quotation  when  we  come  to  speak  of  the  development 
of  ova.  Schmidt  corroborates  Eckhard's  statement  of  the  production  of 
living  germs  from  Stentor  cceruleus,  and  affirms,  in  addition,  that  germs  are 
frequently  extruded  and  developed  outside  the  parent,  and  that  their  subse- 
quent development  from  minute  globular  and  conical  transparent  and  almost 
colourless  organisms,  with  long  cilia,  may  be  watched  thi^ough  all  the  inter- 
mediate stages  until  the  complete  animalcule,  with  its  spiral  ciliary  wreath 
and  mouth,  is  perfected. 

The  preceding  speculations  on  the  development  of  ovules  and  germs  have 
their  importance  materially  modified  by  M.  Balbiani's  recent  researches  and 
hjT^otheses  respecting  the  prevalence  of  a  sexual  mode  of  reproduction  among 
the  Ciliata,  as  detailed  above  (pp.  329-334). 

Spermatozoids  (  ?  ). — This  term  is  provisionally  applied  by  Mr.  Carter  to 
granules  originally  developed  from  the  nucleus  in  Amoeha^  Euglypha,  and 
Spongilla,  and  supposed  by  him  to  impregnate  the  o^^lles.  "  With  reference 
to  the  organs  of  generation,"  he  wiites  (A.  N.  H.  1856,  xviii.  p.  228),  "  in 
the  other  Infusoria,  I  can  state  no  more  than  that,  although  there  is  a  fusiform 
nucleus  in  Otostoma  (XXVIII.  25,  2Q),  I  have  also  constantly  seen  a  bunch 
of  string-like  filaments  floating  about  its  inteiior,  which  appeared  to  be  at- 
tached near  the  buccal  ca\ity  ;  and  although  I  could  make  out  nothing  more,  I 
could  at  the  same  time  only  liken  these  to  the  generative  apparatus  in  the 
Planaria  mentioned,  which  floats  round  the  buccal  cavity  and  upper  part  of 
the  membranous  stomach  in  a  similar  manner." 


338  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

The  notice  of  Mr.  Carter,  of  the  peculiar  structures  he  would  designate 
spermatozoids,  is  as  yet  unconfirmed  by  other  writers ;  and  we  must  therefore 
consider  their  natiu'e  and  purpose  still  suh  jiidice. 

Since  the  above  was  wi'itten,  M.  Balbiani's  researches  (A.  N.  H.  1858,  vol.  i. 
p.  435)  confirm  Mr.  Carter's  opinion  so  far  as  relates  to  the  development  of 
spermatozoids  or  male  reproductive  elements,  but  refers  their  origin  to  the  nu- 
cleolus instead  of  the  nucleus.  In  our  history  of  these  last-named  organs,  we 
have  presented  M.  Balbiani's  vieAvs,  and  must  here  refer  back  to  them  (p.  329). 

Accessory  Contents  : — Granules  ;  Molecules  ;  Spherical  Cells  ;  Sup- 
posed Glands. — Among  the  remaining  contents  of  the  Ciliata  are  numerous 
granules,  molecules  and  fat-cells.  Mr.  Carter  {A.  N.  H.  1856,  xviii.  p.  121) 
makes  a  distinction  between  granules  and  molecules — two  terms  which  by 
others  are  very  loosely  used  and  not  specially  defined.  This  writer,  however, 
would  restrict  the  term  molecules  (moleculae)  to  colouiiess  granules  more 
minute  than  those  he  understands  by  the  latter  appellation.  "  They  differ  in 
size,  and  are  the  first  bodies  that  appear  in  it  (/.  e.  the  sarcode).  ...  By  the 
time  the  ovules  have  become  fully  formed,  the  sarcode  and  its  moleculge  have 
died  off  or  disappeared." 

The  granules  "  make  their  appearance  among  the  molecultc,  and  are  cir- 
culated round  the  abdominal  cavity  in  the  manner  of  the  digestive  globules 
and  particles  of  food.  They  are  of  different  sizes,  but  chiefly  characterized 
by  being  much  larger  than  the  moleculae,  few  in  number,  of  a  circular,  ellip- 
tical, elongated,  subround,  or  irregular  shape,  Tvith  thick  dark  edges,  appa- 
rently produced  by  obstmction  to  the  passage  of  light, — coloiuless,  or  of  a 
yellowish-green  tint.  When  large,  and  Avith  no  other  granular  matters  pre- 
sent but  the  moleculae,  they  form  a  striking  feature  in  the  interior  of  Amoeba, 
VorticeUa,  Oxytricha,  Paramecium  AureJia,  &c. ;  but  at  times  they  are  so  in- 
significant in  size  as  to  be  undistinguishable  from  the  moleculae,  even  if 
present  at  all.  That  they  are  not  ovules  may  be  satisfactorily  seen  when 
both  are  together, — the  dark,  thick,  and  frequently  irregular  edges  and  colour- 
less state  of  the  former  contrasting  strongly  with  the  thin  circular  margin 
and  faint  yellow  tint  of  the  latter.  They  appear  to  increase  in  size  and 
number  vrith  the  age  of  the  Infusorium,  and,  when  fully  developed,  to  remain 
unaltered  in  size,  though  apparently  somewhat  shrivelled  in  form,  until  their 
dissolution.  On  one  occasion,  while  watching  the  metamorphosis  of  an  Oxy- 
triclia  (similar  to,  but  not  the  same  as,  that  described  by  M.  Jules  Haime, 
and  of  which  I  hope  to  give  a  detailed  accoimt  hereafter),  these  granules, 
during  the  formation  of  the  globular  cell  within  the  body,  which  enclosed  the 
materials  from  which  the  Ploesconia  was  ultimately  developed,  became  con- 
gregated together  at  the  posterior  extremity  of  the  Occytricha,  and  remained 
there  in  a  roundish  mass,  shut  out  from  the  cell,  until  the  latter  burst  for 
the  liberation  of  the  Ploesconia,  when,  with  the  deciduous  coverings,  they 
passed  into  dissolution.  Of  the  nature  of  their  ofiice  I  am  ignorant ;  but  they 
are  sufficiently  remarkable  and  constant  to  demand  particular  notice." 

Perty  speaks  of  molecules  and  granules  together,  and  expresses  his  opinion 
that  some  are  simple  fat-corpuscles,  and  others  the  first  rudiments  of  internal 
germs  or  ovules.  Stein  also  carefully  distinguishes  fat-granules  from  others 
not  fatty.  In  Opercularia,  Epistylis,  and  alhed  genera  of  Vorticellina ,  this 
observer  points  out  that  no  particles  of  food  penetrate  to  the  posterior  extre- 
mity, where  its  diameter  is  narrowed  to  unite  with  the  stem,  but  that  this 
region  is  occupied  with  a  heap  of  large  fat-corpuscles  and  of  minute  granules 
of  probably  the  same  nature.  Isolated  corpuscles  resemble  precisely  the  fat- 
particles  scattered  through  the  body.  He  cannot  assent  to  Ehrenberg's  pro- 
position, that  this  heap  of  granules  represents  a  sort  of  loose  ovary,  but  would 


OF  THE  PROTOZOA. CILIATA.  339 

consider  it  to  be  a  store  of  nutritive  matter  specially  intended  to  furnish  the 
material  required  in  the  construction  of  the  stem. 

Under  the  name  of  '^  spherical  cells  "  Mr.  Carter  (op.  cit.  p.  124)  describes 
some  special  structures,  which,  so  far  as  we  know,  are  not  mentioned  by  any 
other  observer.  "  They  abound,"  he  writes,  "  in  the  sarcode  of  Otostoma 
(XXYIII.  2d,  26),  and  apparently  in  many  of  Ehrenberg's  *  Allotreta.'  In 
Otostoma  they  are  of  different  sizes,  because  they  are  in  all  stages  of  develop- 
ment ;  and  to  keep  up  their  numbers  without  distending  the  animalcule,  they 
must  be  continually  undergoing  rapid  decay  as  well  as  reproduction.  The 
most  remarkable  feature  in  them  is,  that  the  largest  contain,  besides  other 
granular  bodies,  several  small  cells  filled  with  a  yellowish-brown  fluid  ;  and 
these  cells  are  also  found  free  among  the  general  group ;  but  of  what  their 
ultimate  destination  is,  as  they  do  not  appear  to  grow  larger,  or  to  become  re- 
productive, we  know  nothing."  On  comparing  these  cells  with  those  seen 
in  the  stomachs  of  Planarice  and  Rotifera,  Mr.  Carter  concludes  that  they  are 
homologous  with  them,  and  represent  a  biliary  secreting  organ.  "Although," 
he  adds,  "  ovules  may  occasionally  issue  together  with  these  cells  from  Oto- 
stoma, &c.  as  well  as  from  the  Planarm,  yet  the  two  can  hardly  be  con- 
founded." 

On  the  correctness  of  this  description  we  have  no  means  of  deciding  :  the 
genus  Otostoma  has  not  fallen  imder  our  observation ;  and  the  figm^es  to  illus- 
trate these  spherical  cells  convey  no  clear  conception  of  their  characters.  We 
might  hazard  the  conjecture  that  these  supposed  definite  cells  are  only  glo- 
bides  of  food  ;  for  we  are  scarcely  prepared  to  admit  the  existence  of  hepatic 
cells  in  the  simple  tissue  of  Protozoa,  between  which  and  the  complex  organ- 
ization of  Rotifera,  Avith  their  true  membranous  stomach,  so  wide  a  difierence 
subsists  that  no  true  homology  can  obtain. 

Perhaps  the  coloured  "  spherical  cells  "  of  Mr.  Carter  are  identical  with 
the  yelloTsish  and  brown  vesicles  Perty  {op.  cit.  p.  53)  separated  from  Nas- 
sula  aurea  by  crushing  it  between  the  glass  slide  and  cover,  from  -g-jjVjj'" 
to  Y^nnr  '  ^^^  ^^^®'  ^^^  which  he  concluded  to  be  fat-globules,  and  only 
another  stage  of  development  of  numerous  smaller  white  corpuscles  he  met 
with  in  the  same  being. 

Stein  has  established  the  existence  of  a  pair  of  oblong  or  reniform  soUd 
glandular-looldng  organs  a  little  beneath  the  peristom  of  Optercularia  arti- 
culata  (XXX.  20),  the  purpose  of  which  cannot  be  surmised.  Lachmann 
has  hinted  at  the  possibility  of  their  being  nervous  ganglions,  but  neverthe- 
less feels  quite  unable  to  express  an  opinion. 

The  chlorophyll-corpuscles,  chiefiy  confined  to  the  soft  subtegumentary 
lamina,  have  already  been  spoken  of  (p.  297),  and  need  no  further  notice, 
except  it  be  to  recall  an  opinion  of  Cohn,  that  the  coloured  masses,  called 
by  Ehrenberg  ciliary  glands,  seen  in  a  few  species  of  Nassula,  are  probably 
of  the  same  nature  as  those  corpuscles. 

Circulation  of  Contents  (XXIX.  25). — The  remarkable  phenomenon 
of  the  circulation  or  rotation  of  a  portion  of  the  contents,  similar  to  the  cy- 
closis  in  the  cells  of  many  plants,  is  witnessed  in  most  of  the  Ciliated  Protozoa. 
It  had  attracted  the  notice  of  several  observers  before  Ehrenberg  published 
his  great  work  in  1838,  and  was  very  speedily  urged  in  argument  against  his 
views  of  polygastric  organization,  to  which,  indeed,  it  seemed  fatal,  inasmucli 
as  such  a  rotation  is  clearly  incompatible  with  the  existence  of  stomachs  at- 
tached to,  and  connected  together  by,  a  fixed  intestine.  To  meet  the  objec- 
tion thus  raised,  the  Berlin  professor  suggested  that  the  apparent  circulation 
was  abnormal,  or  a  diseased  condition,  the  consequence  of  an  over- distension 
of  one  stomach-sac  at  the  sacrifice  of  others,  an  explanation  quite  inadmissi- 


340  GENERAL  HISTOKY  OF  THE  INFTJSOEIA. 

ble,  since  the  phenomenon  is  one  to  be  very  frequently  observed  in  animal- 
cules e^ddently  in  full  functional  activity  and  uninjured,  and  because  the 
particles  of  food  entering  the  interior  assume  their  usual  globular  form  (i.  e. 
acquire  the  characters  given  by  Ehrenberg  to  his  so-called  stomach-sacs),  take 
their  usual  course,  and  do  not  accumulate  in  a  confused  manner  wdthin  a  large 
sac,  such  as  the  supposition  in  question  implies. 

Microscopists  are  now  agreed  in  representing  this  rotation  to  be  confined 
to  a  layer  or  stratum  of  the  contents  within  the  subtegumentary  or  cortical 
lamina,  and  not  to  extend  to  the  central  portion,  as  Cohn  represented  (Zeitschr. 
1851,  p.  265).  The  current  is  from  left  to  right,  as  we  look  down  upon 
the  animalcule  (XXIX.  25)  under  the  microscope,  and  therefore  is  actually 
the  reverse,  or  from  right  to  left,  with  regard  to  the  animal  itself.  It  never 
changes  its  direction  or  course  ;  but  its  rapidity  varies  in  different  species,  and 
even  in  the  same  species  under  diiferent  circumstances  affecting  its  vitahty : 
such  are,  among  external  conditions,  hght,  air,  warmth,  and  food  ;  others,  age, 
the  encysting  and  reproductive  acts.  Cohn  observed  that  some  particles  in  a 
Paramecium  Bursaria  occupied  1^  to  2  minutes  in  making  the  circuit.  In 
Vorticella  the  current  is  slower.  The  stream  is  composed  of  a  thin  mu- 
cilaginous matter,  bearing  in  it  numerous  granules  and  molecules,  fat- cor- 
puscles, globules  of  food  (the  stomach-sacs  of  Ehren])erg),  and  the  remnants 
of  alimentary  matters  in  their  passage  to  the  discharging  outlet.  The  chlo- 
rophyll-corpuscles of  the  cortical  layer,  the  nucleus,  and  the  contractile  vesi- 
cles are  not  involved  in  the  cmTent,  unless,  indeed,  a  few  of  the  first  named 
when  accidentally  detached  from  their  matrix.  The  nucleus  lies  more  or  less 
within  the  stream ;  and  although  moveable  to  a  considerable  extent  at  times 
by  the  onward  pressure  of  a  bolus  of  food,  it  yet  seems  to  maintain  a  con- 
nexion with  the  subtegumentarj'  lamina,  and  to  escape  being  drawn  into  the 
rotating  current.  Further,  in  the  large  Vorticelliyia,  such  as  Ejoistylis  and 
Opercidaria,  the  mass  of  fat-corpuscles  at  the  base  of  the  body  does  not  join 
in  the  current ;  and  it  m.ust  be  noted  that  the  food-globules  do  not  circulate 
until  they  have  lost  the  independent  motion  received  by  them  on  their  pro- 
pulsion from  the  extremity  of  the  oesophagus. 

The  most  correct  \dew,  in  our  opinion,  of  the  natiu'e  of  the  rotating  stream, 
is  that  of  Lachmann,  who  conceives  it  to  be  the  nutritive  fluid  elaborated  from 
the  food, — in  a  word,  ^'  chjnne."  Such  a  fluid,  analogy  suggests  to  be  needed 
by  the  cortical  and  sarcode  laminae  over  which  it  spreads  itself,  to  supply  ma- 
terial for  their  renovation  and  rebuilding,  and  to  compensate  for  the  constant 
waste  consequent  on  the  perpetual  movements  of  the  animal.  And  may 
we  not  fiu'thor  presume  that  this  ciuTcnt  also  serves  to  bear  away  from 
the  lamina  effete  pai*ticles  prior  to  their  elimination,  just  as  the  blood 
of  higher  animals  serves  both  as  a  pabulum  to  the  tissues  and  a  channel  for 
the  removal  of  their  worn-out  material  ?  Moreover,  this  circulation  of  a  nu- 
tritive fluid  around  the  inner  layer  of  the  animalcule  has  its  analogy  in  the 
rotation  of  a  similar  fluid  around  the  general  abdominal  cavity  of  the  Ccelen- 
terata,  such  as  the  Ilydi'ozoa  and  Actinozoa. 

Respecting  the  cause  of  this  rotation  of  the  contents,  several  explanations 
have  been  broached.  Some  seeing  in  it  a  close  similarity  to  the  cyclosis  of 
plants,  have  attributed  it  to  a  like  cause  ;  but  what  this  is  in  vegetable  cells 
is  anything  but  certain.  According  to  some,  the  nucleus  of  the  plant-cell  is 
the  exciting  force,  since  the  stream  seems  to  set  out  from  and  to  retui'n  to 
the  nucleus  ;  but  this  is  not  universally  the  case.  Others,  again,  imagine  cilia 
to  cover  the  interior  of  the  cell- wall — but  this  is  only  an  hypothesis, — whilst 
others  find  in  the  functional  activity  of  growth  and  nutrition,  coupled  with 
the  co-ordinate  actions  of  light,  heat,  and  chemical  affinity,  a  sufficient  cause 


OF  THE  PROTOZOA.- — CILIATA.  341 

for  the  phenomenon.  This  last  view  comprehends  the  interpretation  Stein 
puts  upon  the  movement  in  question  in  the  Protozoa,  which  is,  that  the  chlo- 
rophyll-globules by  their  action  on  light,  by  the  exhalation  of  carbonic  acid 
gas,  and  the  resultant  chemical  forces  developed,  produce  the  revolving  move- 
ment ;  for,  as  he  remarks,  the  movements  of  the  animals  have  nothing  to  do 
with  the  rotation,  as  some  have  suggested,  seeing  that  it  goes  on  \^hcn 
they  are  in  perfect  repose  ;  and  moreover  is  seen  only  in  those  rich  in  chlo-' 
rophyll,  and  not  in  colouiiess  individuals. 

In  elucidation  of  chemico-vital  action  as  a  motor  force,  we  may  allude  to 
vegetable  physiology,  which  teaches  us  its  power  in  the  circulation  of  the  sap 
through  the  appointed  channels  in  the  leaves  and  thence  downwards  through 
the  inner  bark.  But,  apart  from  the  influence  of  chemico-vital  forces,  we  cannot 
exclude  the  idea  that  the  propulsive  force  of  the  oesophagus,  in  impelling  food 
or  water  into  the  general  cavity,  must  aid  the  current,  even  if  its  axis  do  not 
precisely  correspond  with  the  course  at  the  point  where  it  is  first  operative, 
since,  from  the  difference  in  the  arcs  described  by  the  course  of  the  stream 
and  by  the  oesophageal  current,  the  two  must  eventually  become  coincident 
and  concurrent. 

In  a  recent  letter  to  us.  Dr.  Strethill  Wright  remarks  that  "  in  Carche- 
siuni  jpolypinum  active  molecular  movements  may  be  detected  throughout 
every  part  of  the  zooid  (animalcule),  even  in  the  thickened  rim  upon  Avhich 
the  cilia  are  placed.  This  movement  seems  to  be  distinct  from  the  rotatory 
motion  of  the  whole  contents  of  the  body,  so  readily  seen  in  Epistylis  grandis, 
and  which  only  occasionally  occurs  in  Carchesium.  The  zooids  of  the  class 
of  Protozoa  seem  to  be  composed  of  sarcode  in  its  most  fluid  state,  enclosed 
in  a  delicate  contractile  coat.  In  this  sarcode  a  desultoiy  circulation  occurs, 
either  as  molecular  motion  or  as  steady  rotation,  or  as  a  backward  and  for- 
ward flowing  occasioned  by  change  of  shape  in  the  body,  as  in  Ojjhr'i/dium 
versatile.^' 

The  Encystestg-peocess  en"  the  Cill\ted  Protozoa  (XXYIII.  6,  7,  66, 
67,  74-76 ;  XXIX.  18, 19,  21-23, 39-46,  52-58).— Although  the  encysting- 
process  is  very  frequently  associated  with  the  act  of  reproduction,  yet  it  is 
also  concerned  'udth  the  preservation  of  individual  life,  and,  so  far,  deserves 
consideration  apart  from  the  former.  Were  it  not  for  some  provision  against 
such  a  contingency,  animalcular  life  would  be  exposed  to  wide-spread  destruc- 
tion by  the  change  of  seasons,  by  the  drying  up  of  the  pools  and  ditches  they 
inhabit,  and  by  other  injurious  external  influences.  Such  a  provision  is  made 
by  the  act  of  encysting,  which  enables  these  minute  animal  organisms  at  all 
ages  to  resist  those  destructive  agencies,  and  also  provides  for  their  almost 
imlimited  diffiision.  The  constniction  of  sheaths  around  animalcules  is  an- 
other protective  act  (see  p.  282),  but  difl'ers  from  encysting  in  not  completely 
enclosing  them. 

When  an  animalcule  is  about  to  encyst  itself,  its  movements  become  less 
active,  and  presently  cease ;  at  the  same  time  it  withdraws  and  folds  up  its 
rotary  or  other  prominent  process,  closes  its  oral  aperture  and  contracts  itself 
in  a  more  or  less  spherical  shape,  and  its  cilia  disappear.  Having  proceeded 
thus  far,  an  excretion  is  thrown  out  around,  which  gradually  hardens,  assumes 
a  membranous  form,  and  invests  the  animalcule  as  a  cyst  or  case.  It  may 
happen  that  the  construction  of  the  cyst  commences  before  the  animal  is 
quiescent,  while  it  still  moves  slowly  about  or  revolves  on  itself  by  the  out- 
pouring of  the  soft  gelatinous  matter  out  of  which  it  is  to  be  elaborated,  as 
is  seen  in  Amphileptus  (XXIX.  19),  Colpoda  (XXIX.  35—43),  and  Chilodon 
(XXIX.  48-58).  Moreover,  after  the  animalcule  is  enclosed  within  its  case, 
it  may  for  a  time  vary  its  figure,  and  also  turn  on  itself  with  more  or  less 


342  GENERAL  HISTORY  OF  THE  INFUSORIA. 

activity,  by  means  of  its  cilia,  which  yet  remain  apparent.  Stein  mentions 
this  phenomenon  in  StylonycTiia  pustidata  (XXIX.  18),  and  in  the  encysted 
embryos  or  gemmae  of  Colpoda ;  and  we  know  that  similar  movements  precede 
its  revival  from  its  quiescent  condition  in  all  cases. 

The  cyst-wall  is,  at  least  in  some  exami^les,  double,  consisting  of  an  outer, 
finely-granular,  softer  layer  and  an  inner,  consistent,  elastic,  homogeneous 
membrane  (XXIX.  21,  22, 41,  43).  It  may  be  that  two  such  laminae  always 
exist ;  for  the  outer  one  crumbles  away  so  soon  as  the  enclosed  animal  prepares 
to  reassume  its  activity,  and  it  is  after  the  onset  of  internal  changes  that 
most  observations  have  been  made  upon  cysts.  The  two  coats  were  remarked 
by  Auerbach  (ZeitscJir.  1854,  p.  431)  in  Oxytricha  PeUioneUa  (XXIX.  21-23) ; 
by  Stein  in  Cliilodon  Cucullidus  (XXIX.  53,  54),  in  Stylonycliia  ]^ustidata 
XXIX.  18),  and  in  Nasstda  ambigua  ;  and  by  Cienkowsky  in  Nasstda  viridis 
(XXYIII.  67),  &c.  In  Chilodon,  indeed.  Stein  represents  several  concentric 
layers  to  the  cysts  (XXIX.  55,  56),  and  states  that  in  this  instance  the  walls 
acquire  no  firmness,  but  remain  soft  and  gelatinous. 

Another  pecuharity  attaching  to  cysts  in  some  species,  is,  that  they 
produce  folds  or  plaits  on  their  surface,  and  therewith  acquire  an  apparent 
angular  outline,  as  Stein  exhibits  in  his  figures  of  encjaieii  Ejjistylis  plkatUh 
and  E.  hrancMopMla,  where  the  lines  are  longitudinal,  and  in  encysted  Oper- 
cidar'ia  berberiformis,  where  they  are  transverse  or  annular. 

Again,  the  cyst-walls  are  not  always  smooth :  thus,  in  Nassida  ambigua 
Stein  represents  them  as  punctate  in  longitudinal  lines  ;  in  Stylonychia  pms- 
tulata  (Midler's  Arcliiv,  1856,  iv.  ;  A.  N.  H.  1857,  xix.  p.  228)  they  have 
stellate  markings,  and  in  a  small  undescribed  species  of  Epistylis  a  finely- 
shagreened  surface. 

The  changes  which  the  encysting  animal  itself  undergoes  have  been  men- 
tioned generally ;  but  a  few  more  details,  aided  by  reference  to  particular 
examples,  are  required  for  a  more  complete  elucidation  of  them.  So  soon  as 
the  animalcule  becomes  quiescent  within  the  sac  secreted  around  it,  the  ciHa 
which  covered  the  surface,  including  any  of  larger  dimensions  disposed  along 
certain  tracts,  or  upon  particular  processes,  disappear,  and  have  generally  been 
presumed  to  be  destroyed  ;  however,  various  obsen^ations  are  on  record  which 
seem  to  show  that  this  is  not  universally  the  case,  but  that  not  imfrequently 
they  are  merely  concealed  from  view ;  and  this  being  so,  it  becomes  ques- 
tionable whether — especially  in  the  ordinary  process  of  encysting,  where 
only  the  conservation  of  the  individual  is  intended — their  destiaiction  or 
absorption  is  the  rule.  An  observation  of  Stein  may  be  quoted  on  this  ques- 
tion : — An  encysted  Chilodon  Cucidhdus,  after  developing  several  embryos, 
ceased  this  process  of  propagation,  redisplayed  its  cilia  as  if  by  simple  evolu- 
tion, and  commenced  mo\dng  within  its  cyst  along  ^vith  one  of  its  embryos 
(XXIX.  58).  The  inference  deducible  from  this  particular  observation  in 
the  case  of  the  encysting-process,  even  when  exercised  for  the  distinct  purpose 
of  generation,  is  greatly  strengthened  by  the  oft-repeated  observations  of  the 
release  of  the  imprisoned  beings,  by  pressure  causing  the  iTipture  of  the  newly- 
formed  cyst,  in  the  possession  of  their  complete  figm^e  and  their  ciliary  arma- 
ture. We  may  add  that  no  proof  exists  of  an  actual  new  formation  of  ciha 
upon  beings  when  emerging  from  their  cyst ;  aU  that  can  be  predicated  is, 
that  cilia  reappear  in  their  normal  positions  and  arrangement. 

To  sketch  now  the  history  of  the  encysting-process  by  a  reference  to  some  of 
the  many  examples  recorded  by  various  microscopists ;  for  the  act  has  been 
witnessed  in  so  many  species  and  genera,  that  it  is  assumed  to  be  common  to 
all.  The  description  given  by  Cohn  (Zeitschr.  1 853,  iv.  p.  267)  of  the  encyst- 
ing of  Trachelitis  Ovum  may  be  given  as  an  example  (XXIX.  19,  20)  : — The 


OF  THE  PROTOZOA. CILIATA'.  843 

movements  of  the  animalcule  become  slower,  and  before  ceasing  altogether, 
consist  in  a  simple  rotation  without  change  of  position.  The  cilia  are  next 
seen  to  become  indistinct  and  to  disappear ;  and  a  delicate  line,  removed  some 
little  distance  from  the  peripheiy  of  the  enclosed  animal,  makes  its  appear- 
ance, indicating  the  limit  of  a  soft  gelatinous  envelope.  Whilst  this  proceeds, 
the  animal  assumes  a  more  globular  and  contracted  figure,  chiefly  by  folding 
do^^-n  its  lip-  or  trunk-hke  process  upon  its  general  sui'face.  The  secreted 
covering  in  the  meanwhile  gains  in  firmness,  but  loses  in  thickness,  and  thus 
acquii'es  the  character  of  a  membrane,  which  closely  invests  the  Trachel'mSy 
except  at  places  Avhere  the  two  surfaces  are  separate  and  distinct. 

This  may  be  termed  the  fii^st  degree  of  encysting,  and  affects  the  creature 
so  slightly  that  it  can  shake  off  its  coating  of  its  own  accord,  and,  by  rupturing 
its  sac,  reassume  its  pristine  appearance  and  activity.  This  phenomenon  was 
witnessed  four  times  in  the  same  individual  by  Cohn,  and  supposed  by  him 
to  have  been  induced  by  the  abnormal  conditions  (the  action  of  light,  &c.)  in 
which  the  animalcule  was  placed  under  the  microscope.  Stein  {op,  cit. 
p.  133)  in  a  similar  manner  recounts  the  formation  of  a  cyst  around  Chilodon 
Cucullulus,  and  the  possibility  of  setting  it  free  by  breaking  down  the  cyst  by 
pressure.  In  Trachelius  the  development  of  the  cyst,  to  the  stage  described, 
occupied,  according  to  Cohn,  only  ten  minutes.  ^Tiere  the  i)rocess  advances 
beyond  this  degree,  the  cyst  commonly  acquires  a  denser  and  firmer  con- 
sistence ;  the  animalcule  can  no  longer  deliver  itself  at  once  of  its  own  accord 
from  its  prison,  but  undergoes  a  further  change  from  its  normal  form,  and 
requires  those  vivifying  influences  of  external  warmth,  light,  and  moisture, 
such  as  spring-time  brings  with  it,  to  arouse  it  from  its  torpid  state,  and  to 
cause  the  reappearance  of  its  hitherto  obliterated  organs. 

Stein  has  very  copious  details  of  the  whole  process  of  encysting  in  various 
Ciliated  Protozoa ;  but  in  none  is  that  process  more  interesting  to  follow  than 
in  the  Vorticellma.  In  members  of  this  family  the  state  of  extreme  contrac- 
tion, induced  by  some  external  cause  obnoxious  to  them,  becomes  fixed,  and 
only  the  irregularly- curved  space  covered  over  by  the  completely-closed 
peristom  indicates  the  complicated  ciliary  apparatus  of  the  head ;  and  even 
this  decreases  to  a  streak,  and  at  length  vanishes  altogether.  Whilst  this 
goes  foi-ward,  a  membrane  forms  around  the  being  which  is  now  detached 
from  its  stem,  and  a  globular  or  ovoid  cyst,  containing  a  nucleus  and  a  con- 
tractile vesicle,  is  the  representative  of  the  once  active  and  elaborately- 
organized  Vorticella. 

To  what  degree  the  encysting  process  may  advance  without  depriving  the 
animal  of  its  ability  to  recover  its  freedom  and  original  character,  is  well  ex- 
emplified by  Auerbach's  observation  on  the  cysts  of  Oxytricha  Pellionella 
(XXIX.  21,  24)  (Zeitschr.  1854,  v.  p.  430).  This  able  microscopist  found  a 
number  of  globular  cysts,  with  two  coats,  enclosing  a  homogeneous,  finely- 
granular,  brown  substance,  within  which  was  a  darker,  rounded  body  (XXIX. 
21),  or  at  times  two,  and  more  rarely  three  such,  seemingly  derived  from  it, 
indicating  the  nucleus.  The  contents  naturally  filled  the  capsule  ;  the  addi- 
tion, however,  of  a  little  mmiatic  acid  caused  them  to  shrink  into  a  roimdish 
body,  somewhat  more  extended  on  one  side,  and  traversed  by  a  few  deep 
folds  or  fissures  (XXIX.  22).  Such  were  the  bodies  met  with  during  the 
continuance  of  winter ;  but  when  early  spring  arrived,  these  began  to  exhibit 
signs  of  vital  activity  within. 

The  fii'st  change  remarked  was  the  appearance  of  a  vesicle,  which  by 
degrees  acquired  increased  contractility ;  then  the  body  retracted  itself  from 
the  cyst-wall  and  commenced  to  revolve  in  a  vacillating  manner,  whilst  the 
outer  granular  lamina  of  the  cyst  broke  away.     Cilia  now  could  he  seen  dis- 


344  OEyERAL  HISTORY  OF  THE  INFUSORIA. 

tributed  over  the  surface  of  the  animal,  and  a  close  row  of  much  stronger  ones 
along  a  fold  recalling  the  characteristics  of  StylonijcMa  or  of  Oxytricha, 
although  the  animal  still  wanted  the  general  confonnation  of  the  body 
peculiar  to  either  of  these  genera  (XXIX.  23).  All  this  time  the  darker 
nuclear  body  or  bodies  had  retained  their  existence  and  position,  whilst  the 
contractile  vesicle,  on  the  other  hand,  grew  smaller,  apparently  by  the  ex- 
pulsion of  part  of  its  fluid  contents  to  occupy  the  space  left  between  the 
animal  and  its  capsule  by  the  contraction  of  the  former.  The  enclosed  body, 
when  freed  from  the  wall  of  the  cyst,  commenced  moving,  not  in  a  regular 
rotation,  but  in  a  jerking  manner,  from  side  to  side  as  it  tiu'ned,  until  at 
length  it  ruptured  the  walls  of  its  piison  and  made  its  escape.  The  animal 
thus  set  at  large  presented  the  characters  of  Oxytricha  (XXIX.  24)  di- 
stinctly enough  to  recognize  it  as  belonging  to  the  genus  ;  and  at  the  same 
time  the  numerous  escaping  germs  and  the  rapid  appearance  of  a  multitude 
of  O.vytricha  Pellionella  of  all  sizes  confirmed  this  view  of  their  nature. 
Nevertheless  a  slight  difference  existed  between  the  newly- emerged  indi- 
viduals and  mature  specimens, — the  former  being  more  oval,  and  theii'  contents 
less  hyaline,  more  granular,  and  of  a  yellowish  colour  by  transmitted  light : 
still,  specimens  occurred  of  every  intermediate  shade. 

This  observation  by  Auerbach  demonstrates  to  us  how  completely  modified 
and  actually  lost  the  characters  of  an  animalcule  may  be  when  it  becomes 
encysted  even  temporarily,  during  what  has  been  termed  the  winter-sleep  ; 
for,  as  that  writer  shows,  the  O.vytricha-cjsts  he  discovered  could  not  have 
been  ova,  or  a  mere  transitional  phase  to  a  higher  form  of  existence.  Similar 
instances  of  cyst -evolution  are  recorded  by  other  observers ;  but  generally  the 
whole  histoiy  of  the  cyst  is  not  given,  but  only  that  portion  in  which  an 
actual  animalcular  form,  in  movement  by  means  of  cilia,  has  revealed  itself; 
such  is  the  instance  of  AmphUeptiis  Fasciola  mentioned  by  Cohn  (Zeitschr.  v. 
1854,  p.  434).  Furthermore,  vaiiations  in  the  internal  appearance  and  per- 
ceptible contents  of  cysts  vary  in  different  species,  just  as  do  theii'  walls  ; 
thus,  for  example,  in  Odyfyicha-cjats  the  contractile  vesicle  had  vanished  and 
appeared  de  novo  only  when  its  vital  activity  was  resumed, — while  in  other 
cases  this  sac  or  space  never  disappears,  but  is  even  more  prominent  than 
the  nucleus  before  the  action  of  reagents,  which  is  tnie  of  most,  or  of  all, 
Vorticellina. 

The  particulars  recounted  by  Mr.  Brightwell  respecting  ZootJiamnimn 
Arbuscida  ('  Fauna  Infusoria  of  Norfolk,'  1848),  which  he  thought  indicative 
of  a  mode  of  development  by  alternate  generation,  appear  to  us  to  represent 
probably  the  act  of  encysting,  or  that  degree  of  it  assumed  by  gemmae  prior 
to  detachment  from  their  parent  stem,  and  retained  by  them  until  they  have 
taken  up  a  fixed  position  and  proceed  to  develop  a  peduncle  (see  section 
on  Fission  and  Gemmation).  We  extract  Mr.  BrightweU's  account,  so  that 
our  readers  may  form  their  own  opinion  of  the  nature  of  the  phenomena 
detailed : — ■ 

"  Sept.  16th,  1846.  Early  in  the  morning  of  this  day,  we  observed  one  of 
the  Zoothamnmm  arbuscida,  a  large  old  specimen,  w^hich  had  lost  all  its 
small  bell-shaped  animals,  but  had  several  medlar-shaped  buds  or  ova  re- 
maining upon  it.  It  was  seen  to  detach  from  its  stalks  nearly  all  these  ova, 
which  went  off  as  free  animals.  One  of  them  soon  after  settled  at  the  side  of 
the  water-trough,  and  after  agitating  its  anterior  cilia  it  suddenly,  and  with 
a  kind  of  violent  effort,  opened  into  a  cup-shaped  form,  and  darted  about 
with  great  rapidity,  occasionally  settling,  and  darting  off  again. 

'*  At  nine  in  the  morning,  one  of  these  buds,  or  ova,  was  observed  fixed  to 
the  glass  by  a  sheathed  pedicle  ;  a  ciliary  motion  became  perceptible  at  the 


OF  THE  PROTOZOA. CILIATA.  345 

top  of  the  bulb ;  and  at  ten  it  had  divided  longitudinally  into  two  buds,  each 
supported  by  a  short  stalk.  The  ciliary  motion  continued  in  the  centre  of 
each  of  these  two  buds,  which  by  degrees  expanded  longitudinally,  and  at 
twelve  had  become  foiu'  buds.  By  four  in  the  afternoon,  these  four  buds  had 
divided  in  like  manner  and  increased  to  nine,  with  an  elongated  foot-stalk,  and 
interior  contractile  muscle. 

"  Dming  the  development  of  another  specimen,  the  stalk  ai^peared  to  have 
transverse  ribs  or  joints,  and,  whilst  a  drawing  was  making,  gradually  bent 
do^vn wards,  and  all  the  buds  severally  detached  themselves  from  it,  and  w^ent 
off  as  free  animals,  leading  only  the  bent  stalk.  In  this  interesting  process 
we  see  something  analogous  to  what  Steenstrup  describes  as  '  a  mode  of 
development  by  means  of  niu'ses  or  intermediate  generations.' 

*"  This  mode  is  described  as  that  in  which  an  animal  produces  a  progeny 
pei-mancntly  dissimilar  to  itself,  but  which  progeny  produces  a  new  generation 
in  itself  or  its  offspiing,  returning  to  the  form  of  the  parent  animal.  It 
will  be  seen  that  this  development  differs  from  that  of  metamorphosis  in 
-  the  cii'cumstance  of  the  intermediate  animal  (the  nurse)  being  itself  a  perma- 
nent and  producing  form. 

'•  To  show  this  to  be  the  case  \^dth  Zoothamnium,  it  would  be  necessary  to 
prove  that  the  medlar- shaped  animals  were  a  permanent  form,  producing  a 
race  which,  in  themselves  or  in  what  they  produced,  returned  to  the  form  of 
the  parent  animal. 

*•'  We  have  not  been  able  to  carry  the  development  of  these  buds  or  ova 
further  than  PI.  12.  f.  67,  68,  69,  and  wood  cut "  (see  Part  II.).  '^  And  it  is 
remarkable  that  in  aU  these  the  buds  have  produced,  not  the  little  beU-shaped 
animalcules  like  the  parent  animal,  but  other  buds  like  themselves.  May  it 
not  be  the  case,  that  these  medlar-shaped  bodies  are  propagated  at  the  close 
of  the  year,  and  that,  when  the  plant  to  which  the  Zoothamnia  bearing  these 
bodies  are  attached  dies  away,  they  remain  in  the  mud,  protected  from  the  cold 
of  the  T\anter,  and  in  the  spring  burst  forth,  and  settle  upon  the  new-gro^dno- 
plants,  and  produce  animals  of  the  parent-fonn.  They  would  thus  form  an 
intermediate  nursing  race  answering  to  Steenstrup's  description." 

Prof.  Cienkowsky  has  witnessed  (Zeitschr.  1855,  vi.  p.  301)  cyst-construc- 
tion in  NassuJa  vlridis  (Duj.)  (XXYIII.  65 — 71),  Stylonychia  jpustulata 
(XXYIII.  74 — 76),  >S^.  Icmceolata,  in  various  VorticeUce,  in  Bursaria  trunca- 
tella,  B.  Jateritia,  Poclo^hrya  jixa,  Loxodes  CucuUulus  fDuj.),  Leucophrys 
Spathula,  AmphUejotus  margaritifer,  Ilolojohrya  brunnea,  and  less  completely  in 
Amphileptus  Anas,  Stylonychia  Mytilus,  Paramecium  chrysalis,  Spirosiomum 
ambiguum,  Stentor po(ymorj)hus,  St.  Millleri,  Paramecium  AureJia,  and  Loxodes 
Bursaria. 

In  Loxodes  Cvcidhdus  (Duj.)  and  Stylonychia  pmstidata  he  saw  the  dis- 
charge of  the  whole  of  the  contents  of  the  cyst  in  the  form  of  encvsted  Infu- 
soria. The  embiyo  born  from  the  cysts  of  Stylonychia  pustulata  resembles 
closely  the  Triclioda  Lynceus,  and  can  multiply  itself  by  self-fission  just  in 
the  same  manner  as  mature  and  independent  beings. 

In  cyst- development,  he  observes,  the  whole  of  the  contents  are,  as  Jules 
Haime  stated,  not  metamorphosed  into  the  resultant  embryo,  but  one  or  more 
portions  escape  in  the  form  of  globules,  apparently  ciliated,  and  move  off  with 
a  rotating  motion. 

PEPEonrcTiox  of  the  Ciliated  Protozoa: — Fission,  modes  of;  Gemmation- 
INTERNAL  Ova  producing  Ghrms  or  Embryos  ;  Impregnation  ;  Production 
of  new  Beings  a^ith  and  without  Metamorphosis  ;  Transformation  into 
Acinet^,  and  Development  of  Embryos. — Until  lately,  naturahsts  in  general 
did  not  acknowledge  other  methods  of  reproduction  than  by  fission,  or,  as 


346  GENEEAL  HISTORY  OF  THE  INFrSOEIA. 

some  would  call  it,  fissation,  and  by  gemmatioii  or  budding,  which,  from  not 
being  true  generative  acts,  have  been  called  '  vegetative '  modes  of  propagation 
or  multiplication.  Kecently,  however,  the  Ciliata  have  had  attributed  to  them 
true  generative  processes,  resulting  in  the  development  of  embryos  either  with 
or  without  intercurrent  metamorphoses. 

The  simpler  processes  of  fission  and  gemmation  are,  in  Stein's  opinion,  modes 
of  propagation  pecuhar  to  immatiu-e  beings,  and  are  replaced  in  mature 
animalcules  by  the  agency  of  germs  or  embiyos. 

Fissiojsr. — This  duplicative  subdivision  may  be  longitudinal,  transverse,  or 
obhque ;  and  whilst  some  species  divide  in  only  one  dii'ection,  others  are 
capable  of  so  doing  in  two,  for  instance,  in  the  longitudinal  and  transverse, 
but  not  simidtaneously.  Among  the  VortkelUna  longitudinal  fission  alone 
occurs  ;  Paramecium  (XXIX.  27),  Chilodon,  and  others  divide  both  longi- 
tudinally and  transversely;  Lacjenophrys  obliquely  only.  Fission  has  not 
been  mtnessed  in  SjiirocJiona  nor  in  Trichodina,  nor  in  Coljjoda  when  in  a 
free  state  and  not  encysted. 

Ehrenberg  came  to  the  conclusion  that  multiplication  by  spontaneous  divi- 
sion is  the  character  which  separates  animals  from  j)lants.  It  is  true  (he 
argued)  that  gemmation  in  plants,  especially  in  veiy  simple  cells,  is  at  times 
very  similar  to  the  division  in  animals ;  but  this  relates  to  the  form,  not  the 
formation.  A  vegetable  cell,  apparently  capable  of  self-division,  produces 
one,  or  contemporaneously  many  exterior  buds  (gemma;),  vrithout  any  change 
in  its  interior.  An  animal  which  is  capable  of  di\ision,  first  doubles  the  inner 
organs,  and  subsequently  decreases  exteriorly  in  size.  Self-division  proceeds 
from  the  interior  towards  the  exterior,  from  the  centre  to  the  periphery' ; 
gemmation,  which  also  occurs  in  animals,  proceeds  from  the  exterior  towards 
the  interior,  and  forms  first  a  wart,  which  then  gradually  becomes  organized. 

This  supposed  distinction  between  fission  in  vegetable  cells  and  that  in 
simple  animals  like  Infusoria  is  set  aside  by  modern  researches,  which  show 
that,  when  a  plant- cell  is  about  to  divide,  the  mucilaginous  layer  of  the  wall 
(L  e.  the  primordial  utricle)  manifests  a  constriction,  which  presently  involves 
the  waU  itself,  and,  gradually  deepening,  at  length  cuts  the  ceU  into  two.  The 
observations  on  this  subject  in  the  chapters  on  Desmidie^  and  Diatome^  will 
more  completely  elucidate  it. 

Considered  with  respect  to  the  condition  of  the  animalcule,  fission  occurs 
in  the  active  and  unchanged  state,  as  in  Paramecium  ;  or  In  a  contracted  state, 
as  in  Vorticellina ;  or  only  when  encysted,  as  in  the  case  of  Colpoda.  Hence 
it  follows,  that  it  presents  several  slight  modifications  in  its  course.  One 
general  fact  is,  that  whilst  fission  proceeds,  the  rotation  of  the  contents  of  the 
animalcule  is  at  a  stand- still.  In  its  simplest  variety,  the  dividing  being  first 
presents  a  constriction  at  each  pole  or  side  of  the  body,  which  gradually  ex- 
tends until  it  completely  cuts  it  into  two  equal  or  unequal  parts.  Simulta- 
neously Avith  the  fh'st  indication  of  an  act  of  fission,  and  in  some  cases  before 
a  sign  of  it  is  to  be  detected  in  the  peripheiy  of  the  animal,  it  has  been 
generally  taught  that  the  nucleus,  after  elongating  and  usually  disposing 
itself  across  the  direction  of  the  line  of  scission,  takes  the  initiative  in  the 
act,  by  commencing  a  fission  of  its  own  substance  (XXIX.  27),  which  sub- 
sequently proceeds  step  by  step  with  that  of  the  entire  body,  until  complete. 
This  statement  is,  according  to  Lachmann  {A.  N.  H.  1857,  xix.  p.  230),  a 
mistake  when  made  respecting  the  Protozoa  generally  ;  for  in  some  cases  the 
division  of  the  nucleus  is  consecutive  to  that  of  the  body,  and  "  in  others, 
again,  the  actual  fissation  of  the  nucleus  does  not  lead  to  that  of  the  body, 
but  embryos  are  developed  in  it ;  "  on  the  other  hand,  ^'  fissation  is  generally 
commenced  rather  bv  a  new  formation  of  contractile  vesicles." 


OF  THE  PROTOZOA. CILIATA.  347 

In  some  species  where  fission  proceeds  on  its  simple  type,  food  may  con- 
tinue to  be  received  for  a  short  period  by  the  di\'iding  animal.  The  small  share 
the  abdominal  contents  within  the  cortical  lamina  have  in  the  \'ital  processes, 
is  shown  by  Lachmann's  observation  of  a  Stylonychia,  "  which,  although  a 
considerable  part  of  its  chyme  had  been  sucked  out  of  it  by  an  Acineta,  still 
imderwent  division,  so  that  one  of  the  gemmules  of  division  swam  away  from 
it  briskly,  and  only  the  other  half  of  the  old  animal  was  destroyed." 

The  direction  of  the  line  of  section  is  perhaps,  when  longitudinal,  usually 
from  before  backwards,  the  constriction  appearing  fii'st  and  advancing  more 
rapidly  at  the  head  ;  but  the  contrary,  according  to  Stein,  prevails  in  Chilodon 
Cucidhdus,  where  the  constriction  makes  its  way  solely  from  the  posterior  pole. 

When  fission  is  transverse  or  oblique  it  necessarily  involves  the  reproduc- 
tion, in  the  posterior  half,  of  the  organs  existing  in  the  anterior,  viz.  the  ciliary 
apparatus  of  the  head,  the  oral  aperture,  the  tube  prolonged  from  it,  and  the 
contractile  vesicle.  So  far,  therefore,  it  approaches  nearer  the  act  of  gemma- 
tion than  does  longitudinal  fission,  wherein  segments  of  the  already  existing 
organs  are  separated  for  the  piu-poses  of  the  new  individual,  and  are  not 
actually  reproduced  or  created  anew.  "  In  those  Infusoria,"  says  Lachmann 
(A.  JSf.  H.  he.  cit.),  ''  in  which  a  peculiar  series  of  stronger  cilia  leads  to  the 
mouth  (such  as  Oxytrkliince  and  Eiq)htece),  the  furrow  in  which  this  series 
of  cilia  is  situated  is  seen,  subsequently  to  or  simultaneously  with  the  division 
of  the  contractile  vesicle,  to  become  produced  backwards  over  the  mouth ;  in 
this  prolongation  cilia  are  produced,  and  its  posterior  extremity  becomes 
deepened  into  a  mouth  and  oesophagus,  which  then  opens  towards  the  ali- 
mentary cavity  of  the  animal ;  then,  simultaneously  with  the  external  con- 
striction of  the  body,  the  new  fuiTow  is  separated  from  the  old  one.  (In 
Stentor  the  new  fi^ontal  series  of  cilia  first  makes  its  appearance  on  the  old 
animal  as  a  lateral  straight  series — the  crista  lateralis  of  Ehrenberg).  In 
animals  which  also  possess  peculiar  processes  of  the  body  as  organs  of  motion 
(hooks,  styles,  &c.),  the  fissation  usually  takes  place  in  such  a  manner,  that 
each  of  the  newly-formed  animals  acquires  a  portion  of  these  from  the  old 
animal,  whilst  the  other  part  is  of  new  formation." 

The  manner  in  which  self-division  proceeds  in  Protozoa  with  a  firm,  and 
seemingly  almost  brittle  integument,  is  exemplified  in  Goleps  (XXTV.  284, 
285).  Along  the  line  of  section  a  new  secretion  of  chitinous  substance  takes 
place,  soft  in  consistence  and  transparent,  which  by  its  increasing  width 
separates  the  two  portions  of  the  original  lorica ;  in  this  interposed  new 
tissue  a  constriction  presently  manifests  itself,  and  advancing  in  depth,  the 
two  segments  are  finally  simdered.  It  thus  comes  to  pass  that  each  product 
of  fission  is  one  half  covered  with  a  dense  shield,  and  the  other  half  with  a 
soft,  yielding  integument.  After  a  while,  more  molecules  make  their  appear- 
ance in  the  latter,  which  gradually  assumes  a  firmness  equal  to  that  of  the 
old  lorica. 

The  Vorticellina,  including  the  Ophrydina,  do  not  divide  until  they  have 
assumed  a  sort  of  semiquiescent  condition,  by  the  complete  withdi-awal  of 
their  ciliary  apparatus  and  the  contraction  of  the  body  generally  into  a  more 
or  less  rounded  or  oval  shape, — in  short,  until  they  have  advanced  one  step 
towards  encysting  themselves. 

Ehrcnberg  portrayed  their  fission  as  a  simple  constriction  advancing  from 
before  backwards  to  separation  of  the  body ;  but  Stein  pointed  out  the  actual 
antecedents  of  the  process.  According  to  the  latter  writer,  the  head-portion 
and  its  appendages  withdraw ;  the  rotary  organ  is  absorbed,  and  also  the 
oesophagus  ;  at  the  same  time  the  contractile  space  vanishes  ;  the  body  ex- 
pands in  width,  the  nucleus  outstretches  itself  across  it,  a  constriction  appears 


348  GENERAL  HISTORY  OF  THE  INFUSORIA. 

on  its  anterior  border,  and,  extending  constantly  in  depth,  at  length  effects  its 
complete  division.  When  the  section  has  reached  the  third  of  the  body,  a 
conical  space  displays  itself  towards  the  anterior  portion  of  each  half  (XXYII. 
3),  lined  by  a  special  membrane,  covered  by  cilia  on  its  posterior  side  or  base, 
which  are  seen  to  vibrate  within  the  cavity.  This  formation  is  the  rudiment 
of  the  futiu^e  rotary  organ.  The  apex  of  the  conical  hollow  is  prolonged  by 
a  canal  which  eventually  opens  on  the  sui-face,  and  thus  establishes  a  con- 
tinuity between  the  lining  membrane  and  the  external  integument.  At  the 
same  time  the  internal  angle  at  the  base  of  the  cone  is  j)roduced  inwards  so 
as  to  form  the  ahmentaiy  tube.  When  these  changes  are  accompHshed,  the 
body  is  half  cut  through,  and  the  appearance  is  rather  that  of  two  indi\-idual 
animalcules  united  posteriorly,  having  their  ciliary  apparatus  retracted,  and 
the  peristom  contracted  in  a  splinter-like  manner  over  it.  Lastly,  the 
advancing  act  of  scission  divides  the  nucleus  ;  and  the  whole  body  becomes 
resolved  into  two  individuals  seated  upon  the  same  stalk.  From  this  account 
it  follows,  that,  of  the  original  organs  of  the  animalcule,  the  nucleus  is  the 
only  one  divided  between  the  two  resultant  beings  by  the  process  of  fission ; 
all  the  rest  are  formed  anew  out  of  the  homogeneous  substance  of  the  body, 
viz.  the  peristom,  the  rotary  organ,  the  alimentary  tube,  and  the  contractile 
vesicle. 

This  absorption  and  renewal  of  parts  during  fissation  is  denied  by  Lachmann, 
who  affirms  that  the  movement  of  the  cilia  upon  the  ciliary  apparatus,  and 
in  the  vestibulum  and  oesophagus,  which  are  closed  up  by  the  peristom,  may 
be  observed  during  the  whole  process.  We  have  no  means  of  deciding  which 
of  these  two  statements  is  correct :  yet  we  rather  incline  to  Stein's  account ; 
for  when  we  admit  that  in  fission  there  is  a  separation  of  all  the  organs  and 
appendages  of  the  body  into  two  portions,  one  to  each  resultant  being,  an  act 
of  stnictural  development  becomes  necessary  to  reproduce  the  remaining  por- 
tion, so  as  to  perfect  each  new  animal  and  to  assimilate  it  in  characters  to 
the  parent.  This  being  the  case,  the  method  of  development  stated  by  Stein 
is  more  consonant  Avith  oiu'  ^dews  of  histogeny  than  that  of  Lachmann. 

The  oblique  fission  of  Lagenophrys  vaginicola  (XXX.  32,  35,  36)  presents 
several  peculiarities.  The  line  of  section  commences  below  the  peristom  on 
one  side,  and  proceeds  diagonally  across  to  the  opposite,  and  thus  gives  rise  to 
an  anterior  lateral  segment  retaining  all  the  special  organs,  and  a  posterior 
lateral  possessing  nothing  save  its  half  of  the  elongated  divided  nucleus. 
Diuing  the  process,  the  anterior  half  continues  in  the  enjoyment  of  all  its 
functions  and  activity  (XXX.  32),  whirls  its  ciliary  organ,  and  takes  in  food 
by  the  mouth  :  the  food,  however,  does  not  reach  to  the  segment  behind ;  and 
whatever  alimentary  particles  might  be  present  in  this  vanish,  and  its  whole 
contained  substance  becomes  homogeneous  and  granular,  the  half  of  the 
curved  band-like  nucleus  extending  into  it.  WTien  the  line  of  section  is  fully 
formed.  Stein  remarks  that  the  posterior  lateral  segment  rather  resembles  a 
gemma  than  the  result  of  self-division,  and  j)roves  how  closely  united  are  the 
two  processes  of  gemmation  and  of  fission. 

WTien  the  scission  is  nearly  complete,  a  contractile  space  appears,  and, 
either  before  or  behind  this,  a  curved  elongated  cavity,  ciliated  on  one  side 
and  produced  upwards  as  a  tube  from  one  angle,  is  formed  (XXX.  35),  out 
of  which  the  rotary  organ  and  peristom  are  developed.  As  there  is  no  room 
for  movement,  the  new  being  lies  motionless  close  against  the  old  one  :  how- 
ever, its  contractile  space  acts  energetically  ;  and  the  alimentary  tube,  filled 
with  fluid,  moves  upwards  and  downwards,  and  from  side  to  side  within  it.  At 
length  a  row  of  cilia  appear  around  the  circumference  of  the  body  ;  and  now 
two  beings  occupy  one  case,  the  anterior  adhering  by  its  peristom  to  the  narrow 


OF  THE  PEOTOZOA. CILIATA.  349 

orifice  of  the  sheath,  whilst  the  posterior  lies  immediately  behind  it,  fixed  from 
want  of  space,  and  unable  to  free  itself  (XXX.  36).  The  question  that  now 
presents  itself  is,  how  is  the  newly-formed  animal  to  escape  its  prison  and 
to  exercise  its  vital  endowments  ?  This,  Stein  has  been  able  to  solve  by  ob- 
servation of  another  species  of  Lagenoplirys,  viz.  L.  Amjpidla.  The  upper  seg- 
ment ceases  to  put  forth  its  ciliary  organs  and  to  take  in  food,  and  shortly 
contracts  itself  and  detaches  its  hold  from  the  opening  of  the  external  sheath, 
developing  simultaneously  a  row  of  cilia  around  its  margin  (XXX.  35).  It 
also  not  unfrequently  happens  that  the  body  is  divided  from  the  peiistom, 
leaving  this  portion  adherent  in  its  natural  position  to  the  orifice  of  the 
sheath,  and  possessed  of  such  remarkable  vitality,  that  it  continues  to  con- 
tract and  dilate,  and  to  implicate  the  orifice  of  the  sheath  itself  in  its  move- 
ments (XXX.  35).  AVhen  the  peristom,  with  a  portion  of  contractile  sarcode 
(35  I)  enclosing  at  times  a  contractile  space  within  it,  thus  plugs  the 
only  outlet  from  the  cyst,  the  two  products  of  fission  cannot  gain  their 
liberty,  and  only  enjoy  the  limited  degree  of  locomotion  allowed  within  theii- 
narrow  prison-house.  But  where,  as  is  more  common,  the  orifice  is  opened, 
they  sooner  or  later  make  their  way  out,  experiencing,  nevertheless,  some 
difficulty  in  passing  through  the  narrow  outlet. 

A  curious  circumstance  pertains  to  these  fission-products  of  Lagenophrys, 
and  indeed  to  those  of  all  the  OpTirydlna  and  Vorticellina,  viz.  they  are  not 
precisely  like  the  parent.  Thus,  the  young  of  Lagenoplirys,  produced  as 
above  described,  exhibit  the  rotary  organ  and  peristom  in  a  contracted  con- 
dition, whilst  a  row  of  ciHa  surrounds  the  body  in  a  ring-Hke  groove  on  the 
abdominal  siuface,  and  serves  the  purpose  of  a  locomotive  organ  (XXX.  35, 
36).  On  the  ventral  aspect,  adds  Stein,  the  figui'e  of  the  animalcule  recalls 
that  of  Stylonychia,  between  w^hich  and  the  normal  form  of  Vorticellina  it 
may  be  considered  a  transitional  type. 

Turning  now  to  the  other  members  of  the  Vorticellina  and  Ophrydina,  we 
see  that  the  history  of  the  fission-products  differs  according  to  their  habits 
and  structural  peculiarities.  In  the  branching  forms  many  of  the  newly - 
formed  beings  proceed  each  to  secrete  from  its  base  a  pedicle,  and  so  continue 
the  dichotomy  of  the  little  arborescent  colony  they  belong  to.  Others,  on 
the  contrary,  detach  themselves  from  the  parent-stem  and  enter  on  a  free  and 
independent  existence.  In  this  case  one  of  the  two  segments  consequent  on 
self-division,  in  order  to  enter  on  its  new  mode  of  Hfe,  undergoes  certain 
modifications  in  structure,  viz.  it  continues  in  a  completely  contracted  state, 
and  a  furrow  appears  about  the  posterior  third  of  the  body,  within  which  a 
ciliary  circlet  develops  as  the  locomotive  organ  of  the  animal  (XXVII.  11). 
This  occurrence  is  general  among  Vorticellce  and  Ophrydina  ;  for  among  the 
former  the  pedicle  never  ramifies,  and  in  the  latter  one  fission -product  must 
quit  the  capsule,  which  serves  as  the  nidus  of  only  one  being  at  a  time. 

The  after-history  of  these  locomotive  segments  is  widely  different  in  dif- 
ferent specimens.  Some,  after  swimming  about  for  a  time,  come  to  a  state 
of  rest,  affix  themselves  by  theii'  posterior  extremity,  and  produce,  according 
to  their  natural  habit,  either  a  stalk  or  a  sheath,  and  resume  aU  the  charac- 
teristics of  the  parent-stock.  Others,  again,  become  quiescent,  but  instead  of  se- 
creting a  pedicle  or  sheath,  proceed  to  encyst  themselves,  either  for  their  own 
preservation  or  preparatory  to  the  fulfilment  of  an  act  of  reproduction.  In- 
deed, the  process  of  encysting  may  overtake  the  animals  whilst  still  seated 
on  their  stalk  or  within  their  case,  and  thus  anticipate  the  formation  of  the 
posterior  ciliary  wi-eath. 

Lastly,  in  a  few  genera,  fission  seems  only,  or  at  least  mostly,  to  occur 
after  the  animalcules  are  encysted.     Stein  represents  this  to  be  the  case  ge- 


350 


GENERAL  HISTORY  OF  THE  INFUSORIA. 


nerally  in  Colpoda  CucuUulus,  which  he  never  found  in  process  of  fission 
(XXIX.  38-47).  Indeed,  Ehrenberg  himself  never  saw  self-division  of 
this  animalcule,  although  he  has,  on  the  authority  and  ambiguous  observa- 
tions of  some  of  the  old  observers,  described  its  occuiTence.  According  to 
Stein's  researches,  encysting  would  not  appear  absolutely  necessary ;  for  he 
witnessed  self-division  in  some  specimens  only  contracted  in  a  spherical  form : 
however,  in  others,  the  more  numerous,  a  cyst  was  thrown  around  the  body 
before  that  process  ensued.  According  to  the  general  plan,  the  Ciliated 
Protozoa  di\ide  into  two  ;  yet  there  are  some — and  Colpoda  is  one  of  such — 
in  which  the  act  of  fission  is  repeated,  and  4,  8,  and  even  16  segments  and 
upwards  result.  The  products  of  fission  have  a  certain  latitude  of  motion 
within  their  cysts,  and  ultimately  escape  by  rupture.  Another  peculiarity 
about  Colpoda  is,  that  the  segments  resulting  from  fission  secrete  individually 
a  capsule  around  themselves,  and  thus  we  have  encysted  beings  enclosed 
within  a  general  cyst.  Lastly,  each  young  cyst  has  its  own  nucleus  and 
contractile  vesicle  (XXIX.  43). 

The  fission  of  the  animal  when  encysted  appears  to  be  the  rule  in  Glau- 
coma ;  for  example,  in  G.  scintillans ;  and  Stein  surmises  that  it  is  this 
occurrence  which  Cohn  witnessed  in  Chilodon  uncinatus,  and  thought  to  be 
two  animalcules  enclosed  within  a  common  cyst,  as  happens  with  Gregarhiw. 

The  importance  of  fission  as  a  means  of  multiplying  individuals  among  the 
CiHata  admits  of  numerous  striking  illustrations.  We  may  quote  one  given 
by  Ehrenberg,  by  no  means  an  extraordinary  instance.  He  made  out  that 
a  single  individual  of  Stylonycliia  Mytilus  lived  nine  days :  during  the  first 
24  hours  it  divided  into  3  ;  and  duiing  the  next  space  of  24  hours  each  of 
these  three  had  subdivided  into  two  beings  ;  so  that  by  self- division  alone 
this  animalcule  can  multiply  itself  three  or  fourfold  in  foiu'  and  twenty  hours, 
and  in  the  space  of  ten  days  be  represented  by  a  million  derived  beings  or 
offshoots.  Another  instance  may  be  adduced  from  the  same  distinguished 
micrographer.  On  the  14th  of  November,  he  divided  a  Paramecium  Aiirelia, 
yL-th  of  a  line  in  length,  into  four  parts,  each  of  which  he  placed  in  a  sepa- 
rate glass.  On  the  17th,  the  glasses  numbered  1  and  4  each  contained  an  iso- 
lated Paramecium  swimming  actively  about.  The  pieces  in  Nos.  3  and  2  had 
disappeared.  On  the  18th,  there  was  no  change.  On  the  19th,  each  animal- 
cule presented  a  constriction  across  the  middle  of  the  body.  On  the  20th, 
No.  1  had  propagated  5  individuals  by  transverse  fission,  and  No.  4  eight 
such.  On  the  21st,  no  change  had  taken  place.  On  the  22nd,  No.  1  contained 
6,  and  No.  4, 18  specimens.  On  the  23rd,  the  beings  produced  were  too  nu- 
merous to  be  counted.  From  these  notes  Ehrenberg  calculated,  if  this  process 
continued  in  activity  for  a  month,  268  millions  might  be  produced.  Apart, 
however,  from  these,  which  we  may  term  speculative  considerations,  we  have 
in  Ophrydium  the  clearest  and  most  direct  evidence  of  the  extent  to  which 
fission  is  carried  out.  On  the  completion  of  self-di\T.sion  in  this  animal,  the 
products  remain  together,  connected  by  a  common  gelatinous  mass  at  their 
base  exerted  by  themselves.  By  the  repetition  of  the  process  again  and  again, 
through  a  long  series,  the  Opliryd'ia  accumulate  in  large  greenish  masses,  or 
poljT^aries,  at  times  of  the  size  of  the  fist  or  even  of  the  head  of  a  man.  Now, 
by  comparing  the  size  of  the  individual  Ophrydia  (about  y^th  of  an  inch  in 
length)  with  that  of  the  masses  they  form,  "some  estimate,"  says  Dr.  Car- 
penter {The  Microscope,  p.  487),  "  may  be  formed  of  the  number  included  in  the 
latter ;  for  a  cubic  inch  would  contain  nearly  e'lgJit  millions  of  them,  if  they  were 
closely  packed  ;  and  many  times  that  number  must  exist  in  the  larger  masses, 
even  making  allowance  for  the  fact  that  the  bodies  of  the  animalcules  are 
separated  from  each  other  by  their  gelatinous  cushion,  and  that  the  masses 


OF  THE  PROTOZOA. CILIATA.  351 

have  their  central  portions  occupied  only  by  water.  Hence  we  have  in  such 
clusters  a  distinct  proof  of  the  extraordinary  extent  to  which  multiplication 
by  duplicative  subdivision  may  proceed  without  the  intei-position  of  any  other 
process.  These  animalcules,  however,  free  themselves  at  times  from  theii- 
gelatinous  bed,  and  have  been  observed  to  undergo  an  '  encysting  process ' 
corresponding  with  that  of  the  VorticelUna.  It  is  much  to  be  desii^ed  that  mi- 
croscopic observers  should  devote  themselves  systematically  to  the  continuous 
study  of  even  the  commonest  and  best-known  forms  of  these  animalcules, 
since  there  is  not  a  single  one  whose  entire  life-history,  from  one  generative 
act  to  another,  is  kno^vn  to  us  ;  and  since  it  cannot  be  even  guessed  at,  with- 
out such  knowledge,  what,  among  the  many  dissimilar  forms  that  have  been 
described  by  Prof.  Ehrenberg  and  others,  are  to  be  accounted  as  tnily  di- 
stinct species,  and  what  are  mere  phases  in  the  existence  of  others  that  are 
perhaps  very  dissimilar  to  them  in  aspect,  it  is  obvious  that  no  credit  is 
really  to  be  gained  by  the  discovery  of  any  number  of  apparently  new  species, 
which  shall  be  at  all  comparable  with  that  to  be  acquii^ed  by  the  complete 
and  satisfactoiy  elucidation  of  the  Kfe-history  of  any  one." 

Gemmation  (iUustrated  by  XXYII.  1-4  ;  XXX.  17,  27,  29,  31,  33,  34).— 
This  is  the  next  process  of  multiplication  to  be  considered.  It  has  much 
analogy  with  fission,  but  is  not  nearly  so  widely  diffused,  being  restricted 
apparently  to  the  families  VorticeUina  and  OpTirydina,  that  is,  to  attached 
species  of  Ciliata ;  yet  even  among  these  it  would  seem  not  to  be  general ; 
for  Stein  has  failed  to  observe  it  in  the  genus  Ojyercularia.  In  it  a  promi- 
nence forms  upon  the  surface,  mostly  near  the  posterior  extremity,  and  of  the 
same  granular  homogeneous  substance  as  the  rest  of  the  animal :  a  line  of 
constriction  soon  displays  itself,  and  gradually  deepens,  whilst  the  budding 
process  increases  in  size  and  developes  internal  organs  and  external  ap- 
pendages, until,  being  sufficiently  perfected  for  an  isolated  existence,  it  severs 
itself  from  the  parent  stock.  The  gemma3  or  buds  thus  produced  are  much 
smaller  than  the  parent,  and,  even  when  they  have  acquired  theii'  largest  di- 
mensions before  separation,  are  less  than  the  new  beings  originating  from 
self-division.  In  everj^  instance  of  fission  the  nucleus  becomes  di\ided  be- 
tween the  two  segments  ;  and  some  authors,  as  we  have  seen,  hold  the  ojdI- 
nion  that  these  share  between  them  a  portion  of  other  pre-existent  organs  of 
the  dividing  animal ;  on  the  other  hand,  in  gemmation  the  bud  is  a  mere 
offshoot  of  the  general  substance,  containing  no  portion  of  any  pre-existing 
organ — not  even,  so  far  as  can  be  seen,  of  the  nucleus ;  and  consequently  all 
the  specially- organized  parts  are  developed  in  it  de  novo.  If  the  doctrine  of 
internal  germs  be  admitted,  then  it  may  be  imagined  that  each  gemma  origi- 
nates from  one  of  these,  which  takes  on  this  external  direction  of  development. 

On  the  completion  of  the  gemma,  we  find  that  it  resembles  (except  in  Spi- 
rocliona  and  Lagenophrys)  a  completely- contracted  specimen  of  the  parent 
animalcule,  and  possesses,  in  lieu  of  the  usual  ciliated  whorl  on  the  head, 
a  posterior  ciliary  wreath,  whereby,  when  detached,  it  swims  freely  away, 
'wdth  the  posterior  extremity,  however,  in  advance.  It  resembles,  therefore, 
in  all  respects  the  product  of  fission  when  separated  from  its  fellow,  and, 
like  it,  may  either  presently  attach  itself,  losing  its  posterior  circlet  of 
cilia,  and  acquire  aU  the  characters  of  its  parent — as  well  as,  in  process 
of  time,  its  dimensions, — or  advance  to  a  completely  encysted  state,  prepara- 
tory to  a  process  of  development,  or  simply  for  the  object  of  preservation 
from  untoward  external  conditions.  The  act  of  gemmation  goes  on  alike  in 
small  and  in  large  specimens.  Stein  notes  its  occuiTcnce  in  Vorticelke  of  only 
^"'  in  length. 

A  few  illustrations  may  render  the  above  account  of  gemmation  more  clear. 


352  GENERAL  HISTORY  OF  THE  INFUSORIA. 

Speaking  of  this  process  in  Vorticellce,  Stein  (ojy.  clt.  p.  28)  says,  the  interior 
of  the  knob-like  process  is  quite  homogeneous  at  first  (XXVII.  1)  ;  but  when 
it  has  attained  a  hemispherical  shape,  a  crescentic  cavity  forms  at  its  anterior 
part,  from  which  the  peristom,  rotary  organ,  and  alimentary  tube  are  even- 
tually developed  (XXX.  17,  27),  just  as  happens  in  the  result  of  fission. 
Whilst  this  proceeds,  the  swelling  acquii^es  an  oval  or  globose  figure,  and 
the  width  of  its  attached  base  d^vindIes  to  a  constricted  neck  or  isthmus. 
The  addition  of  acetic  acid  proves  that  no  portion  of  the  nucleus  extends  into 
it,  but  that  this  organ  retains  its  normal  cui'\'ed  reniform  figure.  Stein  here 
adds  the  remark,  that  no  sharp  Kne  of  distinction  exists  between  self-fission 
and  gemmation — that  the  latter  may  be  looked  upon  as  an  act  of  unequal 
division,  in  which  the  whole  organization  has  to  be  created,  and  not,  as  in 
fission,  simply  perpetuated  ;  or  fission  may  be  described  as  a  variety  of 
gemmation,  one  segment  being  regarded  as  a  bud ;  at  least  this  view  holds 
good  in  the  case  of  transverse  fission.  Longitudinal  fission  consists  in  the 
formation  of  two  gemmae,  which  subsequently  involve  the  entire  being.  So 
also  in  one  sense  gemmation  does  not  always  end  in  the  production  of  a  single 
bud ;  for  VorticeUce  with  two  are  common,  and  occasionally  with  three,  one  of 
which  is  ready  for  detachment,  whilst  the  other  or  others  are  very  incomplete. 

In  Sp'irochona  (XXX.  17,  27),  which  does  not  multiply  by  fission,  gem- 
mation is  very  frequent ;  and  often  two  buds  are  produced,  one  immediately 
behind  the  other,  the  hindmost  being  first  in  development.  Where  two 
exist,  the  first-fonned  usually  appears  on  the  side  of  the  body  at  its  widest 
part ;  and  the  second  forms  subsequently  in  front  of  it,  nearer  the  neck.  Re- 
latively to  the  size  of  the  parent,  the  bud  is  usually  of  greater  dimensions 
than  in  VorticeUa,  and  may,  by  thrusting  aside  the  head  of  the  Sj;>irochona, 
place  itself  in  the  longitudinal  axis  of  the  body.  \\Tien  the  gemma  com- 
mences to  contract  its  base  and  to  acquii^e  the  form  of  an  independent  being, 
an  opaque,  sharply-defined,  homogeneous  speck  makes  its  appearance  about 
its  middle,  or,  rather,  in  front  of  it,  which,  by  further  development,  becomes 
the  nucleus  (XXX.  17),  wliilst  a  shallow  groove  displays  itself  at  its  anterior 
tiTincate  end,  and  somewhat  later  is  transformed  into  a  curved  and  rather 
angular  ciliated  fissui'e  extending  some  way  down  one  side  of  the  body. 

In  this  so-formed  gemma  of  Spirochona  there  is,  therefore,  a  wide  depar- 
ture from  the  rule  observed  in  any  of  the  VorticeUina  and  Ophrydina.  No 
posterior  ciliary  wreath  is  fonned  ;  and  the  anterior  ciliary  apparatus,  together 
with  the  head  itself,  is  at  first  developed  in  a  temporary  and  rudimentary 
manner.  After  moving  about  for  some  time  by  means  of  the  ciliary  antero- 
lateral chaimel,  the  free  gemma  fixes  itself  by  its  posterior  extremity,  by  an 
adhesive  substance,  or  occasionally  by  a  short  stem  ;  and  then  the  opposite 
sides  of  the  ciliated  furrow  approximate,  and  coalesce  behind,  whilst  in  front 
one  edge  rises  above  the  other  (XXX.  19),  and  soon  forms  a  spirally-con- 
voluted membrane,  which  becomes  clothed  with  cilia  replacing  those  of 
the  old  furrow,  which  are  absorbed  and  disappear  (XXX.  20).  This  growth 
into  perfect  Spirochonce  does  not  happen  with  all  gemmae  ;  for  some  assume  a 
quiescent  condition,  become  encysted,  and,  if  Stein  be  right,  are  ultimately 
converted  into  very  peculiar  Acinetiform  beings — the  Dench-ocometes  para- 
doxus (XXX.  23).  Before  encysting,  the  cilia  cease  to  play,  and  disappear  ; 
and  very  soon  the  furrow  itself  closes  up.  When  enclosed  within  the  trans- 
parent but  firm  capsule,  nothing  but  a  finely-granular  homogeneous  substance 
appears,  containing  the  peculiar  nucleus,  which,  however,  requires  the  action 
of  acetic  acid  to  display  it  (XXX.  21). 

The  process  of  gemmation  presents  several  peculiarities  in  the  genus  La- 
genophrys,  due  mostly  to  the  peculiar  connexion  between  the  enclosed  ani- 


OF  THE  PROTOZOA. CILIATA.  353 

lualeule  and  its  sheath.  Tlie  rule  seems  to  be  that  two  or  four  gemmae  are 
produced  within  the  sheath  at  the  same  time  (XXX.  29,  34)  ;  but  since 
Stein  had  never  encountered  four,  and  very  rarely  three,  gemmae  upon  any 
animalcule,  the  idea  crossed  his  mind  that  these  small  buds  of  Lagenophrys 
might  perhaps  be  embryos  developed  within  the  interior,  and  subsequently 
discharged.  Another- explanation  was  possible,  viz.  that  they  were  animal- 
cules which  had  found  their  way  into  the  sheath,  and  were  quite  foreign  to 
it.  However,  both  these  hypotheses  are  set  aside  by  the  history  of  deve- 
lopment and  by  the  characters  of  the  beings  produced.  The  process  consists 
in  the  enlargement  of  the  posterior  extremity  (XXX.  33),  or  of  a  part  of  the 
side  of  the  Lagenophrys,  and  the  progressive  detachment  of  the  enlargement 
as  a  segment  or  bud,  and  simultaneously  the  production  of  a  band-like  nu- 
cleus and  contractile  vesicle  T\ithin  it.  Tlus  stage  being  so  far  complete,  the 
gemma  does  not  proceed  to  develope  into  the  fonn  of  the  parent  animal,  but 
self-fission  takes  place,  and  two  similar  ovoid  bodies,  each  with  its  contractile 
vesicle,  is  tlie  result  (XXX.  29).  ^^Tien  the  constriction  of  the  single  gemma 
announces  approaching  fi^ssion,  a  circlet  of  cilia  ajipears  on  each  side  of  it 
(XXX.  34) ;  and  on  the  completion  of  the  process,  each  segment  has  a  conical 
head  surrounded  with  a  wreath  of  cilia. 

From  this  mode  of  production  in  pairs,  the  number  of  gemmae  wdthin  the 
sheath  of  Lagenophrys  should  always  be  two  or  a  multiple  of  two ;  hence, 
when  three  are  seen,  it  is  to  be  i^resumed  that  one  has  previously  made  its 
escape.  From  the  peculiar  way  in  which  the  body  of  the  Lagenophrys  is  sus- 
pended by  its  attached  peristom  to  the  orifice  of  the  sheath,  it  is  clearly  im- 
possible that  anything  can  dii-ectly  either  make  its  entrance  into  or  its  escape 
from  the  animal,  without  rupture,  of  which  we  have  no  inchcation.  The  way 
in  which  this  impediment  is  sm-mounted  is,  on  Stein's  authority,  by  the  sudden 
contraction  of  the  body  of  the  Lagenophrys  rupturing  the  adhesion  of  the 
peristom  to  the  orifice  of  the  sheath,  and  by  its  subsequent  retraction  within 
it  (XXX.  31).  In  this  manner  a  free  exit  is  aflforded  to  any  contained 
gemmae ;  and  after  a  certain  time  allowed  for  their  passage,  the  anterior  part 
of  the  body  again  enlarges  itself,  and  reassumes  its  adhesion  to  the  sheath. 
After  their  exit.  Stein  has  no  observations  to  show  what  becomes  of  them ; 
but  his  idea  seems  to  be  that  they  do  not  produce  a  sheath  until  nearly 
arrived  at  maturity,  since  they  are  so  much  smaller  than  the  least  of  the 
sheathed  examples  to  be  met  with. 

If  this  account  be  correct,  the  gemmation  of  Lagenophrys  is  actually  a 
compound  process  of  budding  and  fission,  wliilst  the  resultant  beings  differ 
^ddely  from  those  of  other  Vortlcellhia  in  all  details,  and  are  so  veiy  abeiTant 
in  form  from  the  parent,  that  they  require  to  undergo  a  metamoi^Dhosis  before 
they  gain  it. 

Development  from  Ova.  Ixteexal  Geems  and  Embetos. — Although  the 
reproduction  of  the  Ciliated  Protozoa  is  so  largely  provided  for  by  the  two 
processes  of  fission  and  gemmation  as  just  described,  it  is  even  more 
marvellously  so  by  their  possession  of  true  generative  functions — a  fact 
clearly  established  by  the  latest  obsen'ers,  although  denied  by  Siebold, 
Kolliker,  and  others  some  years  since,  when  the  unicellular  hypothesis 
of  Protozoic  life  militated  against  the  notion  of  the  existence  of  internal 
ova  or  germs.  Even  now,  indeed,  Avhen  we  look  to  the  researches  disclosing 
to  iLS  the  development  and  discharge  of  germs  and  of  living  embryos,  we  find 
diverse  and  contradictoiy  statements  concerning  both  the  antecedent  or  pre- 
paratory acts,  and  the  final  results.  AVe  cannot  attempt  to  reconcile  these 
discrepancies,  but  wiU  record  the  principal  opinions  of  naturalists  and  the 
observations  on  which  they  are  based. 

2  a 


354  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

In  a  previous  page  we  have  stated  the  views  of  Carter  and  Perty,  relative 
to  the  existence  of  ova  or  germs  in  the  inteiior  of  CiUated  Protozoa,  and 
have  rejected  them  as  unsatisfactory.  Further,  when  we  come  to  inquire 
the  process  of  development  of  the  presumed  OM.iles,  their  mode  of  exclusion, 
and  other  particulars  necessary  to  complete  their  history  and  even  theii' 
identification,  we  find  that  those  naturalists  have  no  direct  observations  to 
adduce,  but  can  appeal  only  to  analogy  and  to  some  casual  and  unconfiimed 
observations  of  others.  For  instance,  Mr.  Carter,  when  treating  of  the  develop- 
ment of  ovules,  appeals  to  the  process  in  Spongilla  and  Eiiglyplia,  and  endea- 
vours to  make  out  that,Tvdth  some  modifications,  the  ovules  oiEuglence,  and  pro- 
bably those  of  all  the  Rhizopods  and  Astasice,  have  a  similar  mode  of  generation. 

Perty,  likewise,  unable  to  advance  any  direct  proof  of  the  existence 
of  ovules  and  of  their  discharge,  appeals  to  Eckhard's  observations  on  Stentor 
cceruleus,  which  Oscar  Schmidt  repeated  and  generally  confirmed.  In  the 
recorded  observation  of  Eckhard  {A.  N.  H.  xviii.  1846),  three  or  four 
globules,  in  dififerent  stages  of  development  occurred  in  the  interior  of  the 
Stentor  in  a  row  (XXIX.  8-13) : — "  In  the  fii^st  stage,  the  contents  of  the 
globules,  consisting  of  minute  granules,  exist  most  imperfectly  developed ; 
but  few  granules  at  present  occur,  and  the  globule,  when  it  lies  in  the 
body,  is  not  very  distinct,  on  accoimt  of  the  granular  parenchyma  of  the  lat- 
ter. In  the  second  stage  of  development  (fig.  9)  the  granules  appear  more 
numerous,  the  contents  are  therefore  more  concentrated,  and  the  globules 
can  then  be  very  distinctly  observed  in  the  body.  Fig.  11  shows  the  third 
stage  ;  granules  commence  arranging  themselves  in  a  row Or,  as  some- 
times happens,  they  appear  grouped  in  the  same  manner  at  two  spots.  The 
gTanules  thus  arranged  and  closely  pressed  together,  blend  into  a  glandular 
but  clear  organ  (fig.  12),  in  which  the  granular  structure  cannot  be  any  longer 
detected ;  frequently  it  is  also  divided  in  two  parts.  Lastly,  in  the  situation 
of  the  transparent  glandular  organ  a  row  of  cilia  appears,  evidently  the  mouth 
(fig.  13).  Whether  this  organ  is  formed  immediately  from  the  former,  I 
have  not  been  able  to  ascertain  with  certainty ;  yet  that  it  is  so,  is  extremely 
probable,  since  on  the  one  hand  the  row  of  cilia  occurs  in  the  situation  of  the 
bright  gland,  whilst,  on  the  other  hand,  in  all  the  germs  which  exhibit  this, 
the  former  organ  is  absent.  Simultaneously  \\dth  the  development  of  the 
mouth  there  appear  one  or  two  clear  vesicles  (fig.  13).  On  the  18tli  of 
May  I  observed  in  the  interior  of  St.  cceruleus  a  germ  as  in  fig.  12 ;  I  saw 
the  cilia  very  distinctly  in  motion ;  the  vesicles  were,  however,  still  absent, 
and  they  did  not  escape  on  this  occasion.  On  the  21  st,  I  saw  the  perfect 
form  (fig.  13),  which  issued  out,  whilst  the  parent  animal  swam  away.  I 
now  attentively  observed  the  young  one  to  follow  up  its  fiu'ther  changes, 
perhaps  the  bursting  of  the  carapace  ;  but  I  was  obhged  to  leave  ofi*  watching 
it  in  half  an  hour,  as  I  could  not  vouch  for  the  accuracy  of  further  observa- 
tion on  account  of  the  strain  upon  my  eyes.  On  the  4th  of  June  I  saw  a 
germ  escape,  as  in  fig.  13:  it  differed  from  that  observed  on  the  21st  of 
May ;  for,  being  at  first  roimd,  it  at  once  exhibited  an  incurvation  at  its  lower 
extremity — an  appearance  frequently  observed  in  young  Stentors,  sometimes 
in  old  ones,  when  they  contract  fi'om  the  elongated  form  to  one  more  or 
less  rounded.  I  have  subsequently  once  seen  the  escape  of  a  similar  germ ; 
and  it  appears  to  me  that  the  true  point  of  maturity  is  that  at  which  vesicles 
begin  to  be  visible.  In  Stentor  polymorplms  I  have  observed  two  such 
globules,  but  I  have  not  succeeded  in  seeing  any  perfectly  formed  escape.  In 
autumn  I  have  often  sought  for  the  reciUTcnce  of  this  phenomenon,  but  have 
never  been  able  to  observe  it  so  perfectly  as  in  the  spring,  although  similar 
globules  are  not  rare  in  the  later  parts  of  the  year." 


or  THE  PROTOZOA. CILIATA.  355 

From  the  poriisal  of  this  account,  the  thought  arises,  whether,  instead 
of  proving-  the  existence  and  progressive  development  of  internal  ovules  or 
germs  in  the  sense  Perty  adopts,  it  is  not  another  illustration  of  embryo-de- 
velopment by  a  sort  of  gemmation  or  breaking  up  of  the  nucleus,  such  as  the 
researches  of  Cohn,  Stein,  Lachmann  and  others  have  made  known  to  us,  and 
concerning  which  we  have  now  to  speak  {see  Balbiani's  researches,  p.  329). 

The  development  of  the  nucleus  into  embryos  takes  place  under  different 
circumstances  and  in  a  varied  manner  in  different  genera  of  Ciliated  Protozoa. 
It  may  occui'  either  without  the  previous  encysting  of  the  animalcule,  or  after 
this  process  is  completed.  Again,  in  the  latter  condition,  and  without  ulterior 
change  or  metamori)hosis,  either  a  few  active  embryos,  or  some  encysted 
germs,  may  be  the  result,  or  the  whole  nucleus  may  resolve  itself  into  a 
brood  of  monadiform  beings,  or,  lastly,  according  to  the  views  of  Stein,  the 
encysted  animal"  may  be  metamorphosed  into  an  Acinetiform  being,  out 
of  which  embiyos  are  developed  diverging  in  character  more  or  less  com- 
pletely from  the  original  ciliated  Protozoon,  to  which,  however,  they  eventually 
recur.  The  development  of  embryos  without  the  previous  encysting  of  the 
animalcule  has  been  followed  out  by  Focke,  Cohn,  and  Stein  in  Nassida  and  in 
Pammecium  (Loxodes,  Cohn)  Bursaria  (XXTIII.  10-14,  XXIX.  28  to  34). 
A  portion  of  the  nucleus  is  separated  by  fission  or  by  an  act  of  gemmation, 
and  constitutes  a  more  or  less  orbicular  body,  in  which  a  nucleus  (XXIX.  34), 
and  then  a  contractile  vesicle,  shortly  declare  themselves  (XXIX.  29). 
Focke  surmised  that  the  so-called  nucleolus  originated  this  germ,  which  then 
foimd,  as  it  were,  a  lodgment  and  nutrition  in  the  nucleus  as  in  a  uterus  {see 
Balbiani,  p.  329) ;  but  Stein  affirms  that  this  body  has  nothing  to  do  with  the 
origin  of  the  germ,  and  is  frequently  to  be  seen  separated  and  removed  to  some 
distance  from  the  nucleus  (XXIX.  29).  In  appearance  the  disk-like  germ  is 
finely  granular,  paler  than  the  nucleus,  and  not  surrounded,  like  the  latter, 
with  a  special  membrane.  Cohn  represents  it  as  existing  in  a  distinctly 
Hmited  cavity,  prolonged  to  the  external  surface  as  a  tube  or  oviduct,  and 
terminated  by  a  two-lipped  orifice,  through  wliich  the  embryo  makes  its  exit 
(XXYIII.  11, 12).  According  to  Stein,  however,  no  such  duct  and  external 
orifice  have  an  existence,  except  temporarily,  dming  the  passage  of  the  germ, 
or  germs  when  two  or  more  follow  in  succession.  This  assertion  of  Stein 
is  supported  by  Cohn's  o^vn  observation,  that  the  point  of  extrusion  varied 
in  different  indi^-iduals  in  its  position,  being  at  one  time  at  the  middle, 
at  another  above  it,  at  a  thu'd  below  it,  and,  as  the  inile,  on  the  left  side, 
although  as  an  exception  on  the  right  side  or  even  towards  the  anterior 
margin.  The  act  of  birth  occupies  about  twenty  minutes ;  and  when  the 
embryo  is  about  to  escape,  it  exhibits  a  vibration  on  its  surface,  which  causes 
a  motion  in  the  surrounding  water  and  hastens  its  detachment.  This  motion, 
after  continuing  a  short  time,  ceases,  and  the  little  being  attaches  itself  to  the 
exterior  of  the  parent  (XXIX.  30).  The  chasm  produced  in  the  parent 
during  the  extrusion  soon  closes  up,  and  leaves  no  trace,  except,  it  may  be,  a 
slight  hollow  in  the  sm-face.  The  embryo  has  an  elongated  fissure,  is  rounded 
at  each  end  (XXIX.  30),  and  frequently  rather  contracted  at  its  middle ; 
internally  it  is  finely  granular  and  colomiess — not  greenish,  as  Focke  asserted — 
and  contains,  besides  a  darker  nucleus,  one  or  two  contractile  spaces  (XXYIII. 
14).  Cohn  could  discover  no  mouth ;  but  Stein  displays  in  his  figure  an 
oblique  fold  or  groove  (XXIX.  30),  which  may  possibly  rei)resent  the  oblique 
funnel-like  vestibule  of  the  mature  Paramecium.  The  vibratile  movement 
visible  about  the  surface  indicates  ciliary  action ;  and  if  the  embiyo  be  killed 
■with  iodine,  the  presence  of  long  cilia  is  demonstrated.  StiU  the  most 
peculiar  feature  in  the  new-bom  animalcule  is  the  possession  of  several  soft 

2  a2 


356  GENERAL  HISTORY  OF  THE  INFFSORIA. 

tentacular  processes  at  each  end,  siuTounded  by  small  knobs,  recalling  in 
figure  the  knobbed  tentacles  of  some  Acinetina  (XXYIII.  14,  XXIX.  30) ; 
by  means  of  these  the  embryo  secures  its  hold  to  its  parent.  Such  pro- 
cesses are  not  present  in  all  specimens,  and  are  therefore  non-essential ;  or 
it  may  be  they  have  disappeared  by  withdi^awal  into  the  general  substance 
of  the  body. 

The  embryo  once  freed  from  its  parent,  commences  an  independent  existence, 
moving  freely  about  in  the  water — much  more  similar  in  figure  and  structure, 
however,  to  some  of  Ehrenberg's  Ci/clidina  or  to  Dujardin's  Enchelyens  than 
to  Parameciwn .  Cohn  notes  its  affinity  with  the  Cyclidium  margaritacenmy 
or  to  the  Pantotriclmm  Enchelys  (Ehr.),  and  also  with  several  species  of 
Dujardin's  genus  Enchelys  (Cyclidmm  Ehr.). 

Cohn  adds  that,  in  his  opinion,  several  embryos  are  developed  simultaneously, 
and  that,  where  only  one  or  two  are  found,  others  have  already  escaped.  In 
some  instances  he  has  noticed  as  many  as  six  or  eight  in  process  of  develop- 
ment, and,  it  would  seem,  in  almost  precisely  the  same  stage,  although  their 
birth  is  successive.  Fiu-ther,  besides  these  normal  embryos,  he  has  fre- 
quently witnessed  the  escape  of  others  having  a  globular  figure,  clothed  with 
cilia  and  fm^nished  with  tentacular  processes  and  a  contractile  vesicle. 

During  the  act  of  birth,  the  pulsations  of  the  contractile  space  of  the 
parent  are  uninterrupted,  and  the  rotation  of  the  contents  is  arrested  until 
every  germ  has  escaped.  Another  ciuious  fact  is,  that  the  birth  of  embryos 
may  proceed  as  usual  even  whilst  the  act  of  fission  is  taking  place  in  the 
parent  animal. 

The  further  history  of  the  free  embryo  is  not  known ;  yet,  in  aU  pro- 
bability, it  is  ultimately  transformed  into  a  perfect  Paramecium, — an  event 
which,  from  its  figui'e  and  stnicture,  ensues  readily  and  perhaps  without  more 
than  one  intermediate  phase. 

Judging  from  the  above  details,  it  is  probable,  as  before  remarked,  that  the 
development  of  embryos  in  Stentor  cceruleus  (XXIX.  8)  recorded  by  Eckhard 
{supra,  p.  354)  was  a  precisely  similar  phenomenon  to  that  just  described  in 
Paramecium  ;  and  it  is  clear  that  the  like  obtains  in  Stentor  polymorjjhus,  in 
an  Opalina  or  Bursaria  noticed  by  Siebold  (probably  the  Bursaria  Entozoon 
Ehr.,  parasitic  in  a  frog),  in  Urostyla  grandis,  as  mentioned  by  Cohn,  and  in  the 
animalcule  which  we  conceived  to  be  Trichodina  pedicuJus  {A.  N.  H.  1849, 
iii.  p.  269). 

Since  this  was  written,  the  indefatigable  labours  of  Cohn  have  added, 
another  instance  of  this  endogenous  mode  of  development,  in  Nassula 
elegans  {Zeitschr.  1857,  p.  143;  XXYIII.  11-14).  This  animalcule  possesses 
an  elliptic  nucleus,  having  its  nucleolus  lodged  in  a  fossa  near  one  end,  and 
surrounded  by  a  vesicle,  just  as  in  the  Paramecium  Bursaria.  Among 
many  specimens,  Cohn  found  several  having  a  large,  elliptic,  hollow  space, 
evidently  limited  by  a  membranous  wall.  Where  this  space  approached 
nearest  the  external  surface  of  the  animalcule,  this  was  depressed  in  a  cup- 
like  foiTQ,  and  from  its  centre  a  canal  or  fissure  (XXYIII.  11  /)  penetrated 
the  interior  of  the  space,  where  were  two,  never  more,  large  globules,  pj-jj'" 
in  diameter  (XXYIII.  11  d).  After  a  longer  or  shorter  delay,  these  globules 
escaped  and  appeared  motionless,  without  coloui',  but  granular,  and  having  a 
central  nucleus  and  an  excentric  contractile  vesicle.  As  in  the  instance  of  the 
germs  of  Paramecium  Bursaria,  no  cilia,  but  a  few  short,  knobbed,  radiating, 
tentacular-looking  processes  (XXYIII.  14),  were  visible  on  the  siuface.  Lastly, 
Cohn  noticed  the  formation  of  these  germs  in  animalcules  recently  produced 
by  self-fission,  and  which  had  attained  only  one-half  their  normal  dimensions. 
The  development  of  an  embryo  within  an  encysted  animalcule  is  illustrated 


OF  THE  PROTOZOA. CILIATA.  357 

in  Stem's  history  of  ChUodon  CucuUulus  (op.  cit.  p.  134).  At  a  preceding  page 
(p.  342)  we  have  given  an  abstract  of  the  mode  of  encysting  of  this  animal,  and 
have  stated  that  the  capsule  remains  gelatinous  and  soft.  Inside  the  cyst, 
Stein  discovered  an  actively- moving  embryo  contained  within  a  special  cavity 
(XXIX.  54-56),  occupying  precisely  the  spot  where  in  other  encysted  Chilo- 
clons  the  nucleus  is  found,  -viz.  in  the  chagonal  line  connecting  the  two  oppo- 
site contractile  spaces.  The  embryo  had  an  oval  or  ovate  compressed  figure, 
with  one  side  straight  or  gently  curved,  and  the  anterior  extremity  notched. 
Its  entire  surface  was  covered  with  longitudinal,  widely-separated  rows  of 
unusually  long  cilia,  in  incessant  motion,  which  tiu^ned  it  in  a  spii'al  or  vermi- 
cular manner.  Pressiu-e  on  the  cyst  caused  its  expulsion  (XXIX.  59),  either 
alone  or  together  with  the  substance  of  the  parent- cyst,  to  which  it  always 
remained  adherent.  This  embryo.  Stein  concludes,  is  derived  from  the  nucleus. 
Many  cysts  may  be  met  with  in  which  the  nucleus  is  replaced  by  a  much 
larger  body,  having  a  different  consistence,  opaque  and  motionless,  and 
possessing  in  all  respects  the  outhne  of  a  germ.  On  pressing  it  out  of  its 
place,  its  siu'face  is  seen  to  be  not  quite  naked,  but  to  have  short,  stiff,  and 
imperfectly-developed  cilia  at  one  end  or  entirely  around  its  margin. 

Since  the  embryo  occupies  the  site  of  the  nucleus,  it  might  at  first  sight 
be  supposed  that  the  latter  was  wholly  transformed  into  it;  but  analogy 
leads  us  to  the  contrary  inference,  that  the  nucleus,  although  obscm^ed  from 
view  by  the  internal  germ,  is  nevertheless  present ;  and  this  conclusion  is 
fuiiher  supported  by  the  fact,  that  a  successive  development  of  embi^os  goes 
on  until  the  entire  contents  of  the  cyst  are  used  up  in  their  formation,  an 
event  that  does  not  occur  without  the  influence  of  a  nucleus. 

Stein  declares  the  embiyo  (XXIX.  59)  to  be  precisely  similar  to  Cydidimn 
Glaucoma,  both  in  figure  and  movements.  Its  size  varies  with  that  of  the 
animalcule  producing  it ;  and  individuals  of  aU  sizes  may  imdergo  the 
encysting  process.  The  smallest  cysts  met  with  were  ^"'  in  length,  and 
their  embryo  not  more  than  ^hs'"  >  ^^®  largest  y^-'",  and  their  embryo  from 
■^'"  to  ^■"  (XXIX.  56). 

A  remarkable  circumstance  happens  in  the  case  of  some  encysted  Chilodons, 
even  after  they  have  given  birth  to  one  or  more  embryos, — viz.  that  they 
seem  to  emerge  from  their  quiescent  state  and  resume  their  active  form.  For 
instance.  Stein  met  with  cysts  containing  a  freely-moving  Cliilodon,  together 
with  an  active  embryo,  both  which  ultimately  escaped  by  an  aperture  in 
their  walls  (XXIX.  58).  This  revi\'ification  of  the  ciliated  Chilodon  as  above 
referred  to,  is  urged  by  Stein  as  an  argument  to  prove  that  the  cilia  are  not 
lost  or  destroyed  when  encysting  takes  place,  but  probably  merely  closely 
compressed  against  the  surface. 

Another  variety  of  development  of  germs  within  an  encysted  animalcule 
is  seen  in  Colpoda  Cuctdlus  (XXIX.  35-47),  which  we  have  described  under 
the  head  of  ''  Fission,"  since  the  formation  of  the  germs  is  the  consequence 
of  self-divison  of  the  whole  animal  either  into  two  or,  as  a  rule,  into  four 
segments,  which  themselves  become  individually  encysted,  and  present  their 
own  nucleus  and  contractile  space.  This  plan  of  development  explains  the 
occurrence  of  very  small  encysted  Colpodm. 

It  was  in  this  genus  that  Ehi'enberg  conceived  he  had  made  out  very 
clearly  the  hermaphroditism  and  cyclical  development  of  "  Polygastrica." 

A  third  way  in  which  the  encysting  of  an  animalcule  is  made  to  serve  the 
process  of  development  is  by  the  resolution  of  the  nucleus  into  a  multitude 
of  minute  segments,  each  eventually  assuming  an  independent  animal  ex- 
istence. This  formation  of  what  may  be  caUed  brood-cysts,  occurs,  as 
shown  by  Stein's  later  researches,  in  Vorticella  microstoma  (XXIII.  10-14), 


358  GENEKAL  HiSTOKY  OF  THE  INEUSOKIA. 

Among  cysts  of  the  usual  form  and  dimensions,  are  some  in  which  a  sac,  not 
uniformly  adherent  to  the  inner  surface  of  the  capsule,  contains  from  two  to 
eight,  or,  more  generally,  from  four  to  six,  oval  or  reniform  secondary  sacs, 
irregular  both  in  position  and  size  (XXIII.  10, 11),  and  containing  a  dull  and 
fine  or  coarse  granular  matter,  wdthin  which,  again,  is  a  clear  (contractile  ?) 
space,  but  no  nucleus  is  discoverable  even  when  acetic  acid  is  added.  Pre- 
sently these  vesicles  elongate,  and,  becoming  flask-shaped,  protrude  their 
necks  through  the  enclosing  sac  and  the  cyst-waU  (XXIII.  12,  13),  and 
proceed  to  discharge  their  contents  (XXIII.  14)  through  their  open  extremi- 
ties ;  after  which,  they  corrugate  and  wither.  The  discharged  matter  is 
composed  of  a  mass  of  monadiform  corpuscles  united  together  in  a  globose 
gelatinous  mass,  the  whole  of  the  organic  matter  filling  the  cyst  being  used  up. 

A  precisely  similar  act  of  propagation  Stein  also  witnessed  in  an  encysted 
Vorticella  nehulifera.  Cienkowsky  (ZeitscJir.  Band  vi.  p.  381)  also  reports 
its  occurrence  in  Nassula  vindis,  Duj.  (XXYIII.  65-71);  according  to  this 
author's  researches,  the  contents  of  the  cysts  of  Nassula  vindis  break  up 
into  a  number  of  globular  cells  (XXYIII.  68-70),  which  soon  partake  of  a 
certain  degree  of  rotating  movement  among  themselves,  develope  in  their 
interior  a  multitude  of  wdiat  he  terms  swarm-spores,  and  at  a  certain  period, 
when  mature,  severally  produce,  in  turn,  a  tapering  neck-like  tubular  process 
(XXYIII.  68,  69),  which  perforates  the  softened  cyst-waU  and  gives  exit 
to  the  spores  or  germs  (XXYIII.  71).  This  account  taUies  with  that  given 
by  Stein  of  certain  Vorticella-cysts.  Lachmann  has  the  foUo\\dng  remarks 
on  this  topic  (A.  N.  H.  1857,  xix.  p.  238): — "  It  was  only  in  his  most  recent 
observations  on  Vorticella  microstoma,  that  Stein  saw  the  production  of  larger 
globules,  '  daughter- vesicles'  {Tochterblasen),  in  the  interior  of  the  mother- 
vesicle  ;  but  pre\iously  he  had  seen  nothing  of  the  kind :  it  must  remain 
uncertain  whether  he  had  overlooked  them,  w^hether,  instead  of  several 
globules,  only  one  very  large  one,  entirely  fiUing  the  mother-vesicle,  had 
been  produced,  or  whether  two  different  modes  of  development  actually 
occur  in  this  case.  This  is  the  only  mode  of  reproduction  of  the  Infusoria 
w^hich  has  hitherto  been  observed  in  encysted  animals  alone ;  but  some  ob- 
servations made  by  E.  Claparede  and  myself  upon  an  undescribed  vagini- 
colous  Infusorium,  indicate  that  encystation  is  not  a  necessary  condition 
even  for  this  mode  of  propagation." 

The  last  plan  of  generative  development  to  be  considered  is  that  wherein, 
according  to  Stein's  hypothesis,  the  encysted  animalcule  undergoes  an  actual 
metamorphosis,  and  subsequently,  as  a  rule,  produces  an  embryo  wliich, 
although  very  dissimilar  to  the  original  ciliated  animalcule,  is  nevertheless 
presumed  to  be  convertible  into  it  after  passing  through  one  or  more  trans- 
itory phases  of  existence. 

This  cycle  of  life,  or,  according  to  Steenstrup's  hypothesis,  this  "  alterna- 
tion of  generation,"  in  the  generative  acts  of  ciliated  Protozoa,  Stein  has 
most  diligently  sought  to  establish  as  a  fact,  but,  in  the  opinion  of  most  of 
the  best  naturalists,  has  failed  so  to  do.  Still  the  hypothesis  is  too  curious 
and  interesting  to  be  omitted  from  our  description,  and,  what  is  more,  has 
been  adopted  as  true  by  several  observers.  It  will  therefore  be  best,  fii'st 
to  set  forth  Stein's  own  account,  and  then  to  add  the  remarks  and  objections 
of  others. 

On  some  of  the  branching  stems  of  Epistylis  plicatUis,  and  of  E.  nutans, 
Stein  encountered  not  only  the  ordinary  animalcule  in  full  activity  and  in  a 
contracted  state,  but  also  some  pear-shaped  bodies,  presenting  merely  the 
ordinary  nucleus  and  a  contractile  space,  without  mouth  or  any  remnants  of 
the  alimentary  tube  or  of  food.       On  other  branches,  again,   were   other 


0¥  TUE  PEOTOZOA. CILIATA.  359 

bodies  having  the  figiu'e  of  Acinetce,  furnished  with  tentacles  slightly  move- 
able and  more  or  less  retractile  (XXYII.  17,  18,  19,  20).  These  Acineti- 
form  beings  were  noticed  and  figui'ed  by  our  countryman  Baker  a  century  ago  ; 
they,  moreover,  did  not  escape  the  observation  of  Ehi'enberg,  in  the  alHed 
genus  Oj)e7'cidaria,  hut  were  regarded  by  him  as  parasitic  animalcules. 

On  another  occasion,  Stein  met  with  a  stem  of  Epistylis  plicatilis  bearing 
some  thirty  Acinetce,  diffeiing  among  themselves  very  much,  both  in  size  and 
in  their  stage  of  development.  Each  was  supported  on  a  branch  presenting 
the  characteristics  of  this  species,  but  smaller  in  dimensions,  and  tapering 
from  the  base  of  the  Acinetiform  body  (where  it  had  the  usual  thickness  of 
an  Epistylis-stalk)  to  its  jimction  Tvdth  the  stem  below.  The  length  of  the 
branches  also  varied  greatly,  being  in  some  instances  not  quite  so  much  as  that 
of  the  body  they  supported,  in  others  twice  as  long ;  however,  there  was  no 
proportion  between  the  length  of  the  stem  and  the  size  of  the  body.  Most 
of  the  Acinetoi  had  a  smooth  siuface  and  no  tentacula  ;  they  were  of  a  pyri- 
form  compressed  figure,  and  contained  a  coarsely  granular  and  homogeneous 
substance,  two  or  three  irregularly-placed  contractile  spaces,  and  a  central 
nucleus  ha\TJig  either  the  normal  horse-shoe-  or  an  elongated  oval  shape. 
Where  the  Acinetce  had  tentacles,  these  processes  were  few  and  small,  and  the 
surface  of  the  body  thro^Ti  into  irregularities  by  its  contractions ;  their  nuclei 
were  either  round  or  oval.  These  Acinetce  exhibited  no  movements,  except 
some  slight  ones  affecting  the  tentacula.  Were  their  anterior  extremity  un- 
folded and  theii-  tentacles  outspread,  they  would  assume  the  figure  presented 
by  those  described  in  the  first  observations  on  this  species,  whilst  the  closed 
pyi'iform  bodies  were  precisely  ahke. 

The  further  developmental  history  of  this  particular  E_pistylis  could  not  be 
followed  out,  and  to  arrive  at  the  purpose  of  its  ^cnieto-metamorphosis,  the 
research  was  extended  to  other  species.  A  particular  form  of  Acineta  occurs 
in  company  with  Episti/lis  digitalis,  which  Stein  concluded  to  be  derived  from 
it  by  a  similar  process  to  that  presumed  in  E.  j^Hcatilis,  although  the  Acinetce 
were  isolated  and  seated  on  short  pedicles.  At  the  anterior  part  of  each 
Acineta,  amid  the  large  granules  crowding  the  homogeneous  contents,  were  a 
contractile  space  and,  in  many  specimens,  a  mo\'ing  embiyo  having  a  cylin- 
drical figui'e,  rounded  at  each  end  and  narrower  in  the  middle,  where  several 
zones  of  long  cilia,  in  apparent  folds  of  the  smface,  surrounded  it.  In  ge- 
neral characters  it  would,  as  an  independent  organism,  be  referable  to  the 
genus  Trichoclina,  and  is  probably  no  other  than  the  T.  vonuv  or  T.  gran- 
clineUa,  Ehi'enberg.  The  embryo  escaped  through  a  temporary  opening, 
which  closed  very  speedily  afterwards,  leaving  the  animal  apparently  unin- 
jiu'ed ;  moreover  the  tentacles,  which  are  retracted  during  the  birth,  were 
again  outstretched.  The  conclusion  arrived  at  is,  that  the  Acineta -condition 
is  specially  provided  to  cany  out  embryonic  development,  and  that  in  so  doing 
the  Acineta  gradually  exhausts  itself. 

Stein's  fii'st  impression  was,  that  the  embryo  resulted  from  the  develop- 
ment of  the  entire  nucleus,  and  that  this  organ  was  formed  anew  from  the 
general  contents  of  the  Acineta  ;  however,  later  researches  lead  him  to  be- 
heve  that  only  a  portion  of  the  nucleus  is  concerned  in  building  up  the  em- 
bryo. No  particular  season  seems  devoted  to  this  Acineta -formation,  since 
Stein  has  observed  it  from  the  middle  of  March  through  the  whole  sum- 
mer, and  in  fewer  instances  imtil  December ;  moreover,  embryonic  gene- 
ration is  not  restricted  to  any  particular  size  of  Acineta,  but  occurs  in  all 
except  the  very  smallest ;  nevertheless  the  embryo  is  smaller  proportionably 
to  the  decreasing  size.  Active  embryos  were  seen  in  Acinetce  of  onlj^  ^"', 
the  germ  itself  being  only  Yko'"' 


360  GENERAL  HISTORY  OF  THE  INFrSOElA. 

Besides  the  cysts  and  Acinetce  supported  on  branching  E2jistt/lis-iitem^, 
Stein  found  others  attached  separately  by  very  short  stalks,  or  nearly  sessile  ; 
these,  his  observations  go  to  show,  are  probably  derivable  from  the  beings 
produced  by  fission  or  gemmation,  which  have  detached  themselves  from  the 
parent-stem  in  the  strongly- contracted  or  partially-encysted  condition,  and, 
on  afterwards  fixing  themselves,  proceeded  either  to  complete  their  encysted 
state  or  to  assume  the  Acinetiform  condition. 

Another  set  of  beings  Stein  is  disposed  to  introduce  in  the  developmental 
history  of  Episfiflis  digitalis,  in  the  shape  of  miniature  branching  Vorticellina. 
The  branches  are  dichotomously  disposed,  veiy  slender,  short,  and  rigid. 
Seated  at  the  extremity  of  each  is  a  small  campanulate  being,  with  a  stiff 
bristle  proceeding  from  each  angle  of  the  base  (XXYII.  22,  23).  Internally 
they  are  finely  granular.  They  exhibit  slight  changes  of  outline  and  jerking 
movements  upon  their  stalks ;  they,  moreover,  can  detach  themselves  and 
swim  freely  away  like  a  detached  Epistylis  digitalis,  and  may  sometimes  be 
seen  to  affix  themselves  again  by  their  base  and  produce  a  pedicle.  These 
beings,  whether  derived  from  E.  digitalis  or  from  Carchesium  pygmcPAiin — 
for  they  occur  in  company  with  both  these  animalcules, — their  discoverer 
would  regard  as  their  earliest  phase  of  development,  and  believes  that  not 
improbably  similar  miniature  beings  belong  to  all  the  pedicellate  Vorticellina. 
This  notion  involves  no  great  stretch  of  the  imagination  ;  for  there  is  no  extra- 
ordinary metamorphosis  necessary,  and  we  may  throw  out  the  suggestion  that 
such  minute  Vorticellina  are  developed  from  the  monadiform  contents  of  the 
brood-cysts. 

To  take  another  illustration  of  Stein's  hypothesis  from  the  allied  genus  Ojjer- 
cularia — the  0.  herherina.  Direct  observation  is  wanting  to  identify  the  Aci- 
neta  as  belonging  to  this  Ojjercularia,  except  so  far  as  contiguity  on  the  same 
filament  of  a  plant  or  on  the  same  member  of  a  marine  animal,  and  their  frequent 
occurrence,  be  allowed  to  have  weight.  Stein  argues  that  the  conversion  of  an 
encysted  Opercidaria  into  an  Acineta  is  readily  conceivable,  by  reason  of  their 
congmity  of  form  and  the  existence  of  intermediate  phases,  whilst,  on  the  con- 
trary, the  transformation  of  the  ciliated  embryo  into  an  Acineta,  without  first 
passing  through  the  intervening  stage  of  an  Opercidaria  (a  change  easily 
imagined),  is  a  circumstance  scarcely  probable :  on  similar  grounds  he  would 
associate  the  pear-shaped  Acineta,  ha\ing  a  ramified  nucleus  (XXX.  3,  4), 
with  Opercularia  articidata  (XXX.  1),  as  a  phase  of  existence  interposed 
between  it  and  its  embrj'onic  stage  of  a  free  ciliated  animalcule  ;  but  his 
developmental  history  of  Vorticella  microstoma  is  by  far  the  most  elaborate, 
although  much  too  long  to  present  here  except  in  abstract. 

His  first  step  in  the  investigation  of  this  species  was  the  illustration  of 
the  act  of  encysting  (XXYII.  5  a-d)  in  its  widest  range,  and  the  next, 
to  identify  certain  globular  cysts,  found  in  company  with  the  Vorticellce,  Tvith 
the  cysts  of  those  animals.  These  cysts  were  about  4^'"  in  diameter ;  they 
had  a  clear  double  outhne,  and  contained  a  homogeneous,  transparent,  coloui'- 
less  and  granular  substance.  In  most,  the  characteristic  band-like  nucleus 
and  contractile  space  were  ^dsible,  together  with,  in  many  specimens,  the  in- 
voluted cihary  apparatus  and  oral  ca\T^ty,  looking,  as  a  whole,  hke  a  fissiu'e 
at  the  anterior  part  of  the  cyst  (XXYII.  7,  9).  In  other  cysts,  again,  nought 
could  be  discerned  save  the  nucleus  and  the  contractile  space,  sometimes  di- 
vided (XXYII.  1,8);  and  lastly,  in  others,  all  distinction  of  organs  was  lost, 
the  nucleus  being  the  last  to  disappear  (XXYII.  9). 

Stein  considered,  at  first,  those  peculiar  capsules  to  be  connected  with  the 
process  of  reproduction,  and,  from  meeting  with  torn  empty  sacs,  supposed 
that  the  interior  was  broken  up  into  germs  which  made  their  escape  through 


OF  THE  PROTOZOA. CILIATA.  361 

the  walls.  With  this  interpretation,  however,  he  was  not  satisfied  ;  and  at 
the  same  time  his  attention  was  aroused  to  the  circumstance  of  Vorticellce 
occurring  so  frequently  in  company  with  Actinophrys  and  Podophrya,  and  to 
that  of  the  increase  in  the  number  of  the  one  as  that  of  the  other  decreased. 
He  therefore  applied  himself  to  watch  the  changes  going  on  in  the  cysts  de- 
scribed, and  at  length  satisfied  himself  of  the  intermediate  changes  in  their 
transition  into  Actinoplirys  or  Podojphrya — two  varieties  of  the  same  animal- 
cide,  in  his  opinion,  and  not  two  genera,  as  usually  represented.  Stein  was 
brought  to  the  conclusion  that  this  transition  takes  place,  by  comparing  Podo- 
phryie  at  an  early  stage  of  development  with  metamorphosed  Vorticella-ejsts. 
AmoTigPodophryce  of  the  common  form,  examples  occurred  ha\dng  their  usually 
wide  rounded  capsule  produced  into  a  hollow  funnel-shaped  pedicle,  and  thrown 
into  annular  folds,  alternating  with  acute,  parallel,  angular  ridges  (XXIII. 
3).  Most  of  these  indi\iduals  were  unarmed ;  but  some  had  numerous  capi- 
tate tentacles.  On  the  other  hand,  old  Vorticella-cysts  were  found  in  which  the 
enclosed  animal  had  detached  itself  from  the  cyst-wall,  and  become  thrown  into 
sinuosities  and  elevations,  the  latter  of  which  pressed  against  the  wall,  threat- 
ening to  rupture  it.  These  and  the  above-described  Podophryce  Stein  supposed 
to  merge  into  one  another.  The  leading  changes  noticed  in  the  encysted 
Vorticellce  consisted  in  the  disappearance  of  the  nucleus,  in  the  multiplication 
of  the  contractile  spaces,  and  in  the  detachment  of  the  contents  from  the 
walls  of  the  cyst  (which  they.no  longer  completely  fiUed),  and  their  disposi- 
tion into  irregular  and  changing  lobes.  Thus  far,  in  detecting  such  Vortlcella- 
cysts.  Stein  proceeds  by  direct  observation  ;  but  his  next  step  is  simply  h}"po- 
thesis,  viz.  suj)posing  their  contents  to  shoot  out  tentacula  through  the  dense 
capsule,  and  assume  the  figm-e  of  Actinophrys  or  of  Podophrya  (XXIII.  1,  2, 
4, 18,  19).  That  the  metamorphosis  should  at  one  time  be  into  the  one  ge- 
neric fornix  at  another  into  the  other,  he  endeavours  to  explain  by  assuming 
that  where  no  resistance  is  offered  on  any  side  to  the  developing  Actino- 
phrj^an,  it  assumes  the  form  of  an  Actinophrys,  but  where  resistance  occurs 
at  one  point,  it  there  developes  a  stem  and  becomes  a  Podophrya.  To  coun- 
tenance his  hypothesis  further,  he  appeals  to  the  great  similarity  between 
the  Acifieke  met  with  in  company  with  Vorticella  nehidlfera  on  duck-weed, 
and  Podophi-yce — so  great,  he  says,  that  when  the  former  are  detached,  it  is 
difficult  to  know  them  from  Podophryce. 

Granting  that  the  history  of  metamorphosis  is  thus  far  complete  and 
satisfactory,  it  remains  to  show  what  becomes  of  the  Actinophryans  thus 
transformed  from  the  cysts  of  Vorticellce,  and  to  reply  to  the  question  whe- 
ther they  originate  a  generative  act,  At  the  outset  of  this  inquiry  Stein 
finds  himself  at  variance  mth  KoUiker  and  others  respecting  the  structure 
and  vital  endowments  of  Actinophrys.  The  writers  referred  to  state  Acti- 
twphrys  to  receive  food  within  its  interior,  to  excrete  undigested  matters,  and 
to  exhibit  certain  powers  of  locomotion  ;  these  peculiarities  Stein  ignores,. and 
insists  on  identifjdng  the  Acinetiform  beings  he  has  encountered  with  Actino- 
phrys Sol  and  Podophryafixa,  which,  he  affirms,  give  birth  to  a  ciliated  embryo. 

This  embryo,  he  asserts,  is  produced  within  a  defined  cavity,  so  far  larger 
than  itself  that  it  can  move  mthin  it  (XXIII.  2,  4,  5).  Its  figure  is  pear- 
shaped  mth  a  central  constriction,  and  several  folds  occupied  by  cilia ;  and 
it  ajDpears  composed  of  a  finely-punctate  sarcode,  containing,  in  the  axis  of 
its  posterior  and  larger  segment,  an  oval  or  band-like  nucleus,  and  near 
to  this  a  circular  actively-pulsating  space,  and  occasionally,  on  the  other 
side  of  the  nucleus,  a  second  smaller  one.  No  mouth  could  be  detected. 
The  being,  as  a  whole,  very  closely  resembles  a  detached  gemma  of  Vorticella 
microstoma,  into  which  it  can  be  very  easily  conceived  to  be  changed,  on  fix- 


362  GENEKAL  HlSTOKY  OE  THE  INFUSORIA. 

ing  itself  by  its  anterior  end  and  then  developing,  in  its  larger  and  hitherto 
posterior  segment,  a  mouth  and  ciliary  's\Teath. 

After  Hvely  rotary  movements  -within  what  might  be  called  its  uterine 
cavity,  the  embiyo  escapes  with  a  sudden  bound,  and  gains  a  fi'ee,  active 
existence.  The  passage  by  which  it  has  made  its  way  thi^ough  the  substance 
of  the  parent  Actinophrys  continues  for  some  time  open,  but  is  gradually 
closed  up  from  behind.  The  size  of  the  embryo  is  proportioned  to  that 
of  the  parent,  and  varies  between  jj-^'"  and  -^"'.  The  diameter  of  the 
smallest  parent  being  in  which  a  matiu^e  germ  presented  itself,  scarcely 
exceeded  -J3-". 

One  other  instance  "will  suffice  to  illustrate  Stein's  hypothesis  of  Acineti- 
form  transformation.  The  one  we  select  is  the  Vaginicola  cri/staUina,  which 
that  author  attempts  to  show  becomes,  by  a  metamorphosis,  Acineta  mystacina 
(XXYII.  10-15).  Out  of  a  large  number  of  specimens  contained  in  a 
vessel  of  water,  few  could  be  found  at  the  end  of  foiu'teen  days,  the  place 
of  the  great  majority  ha\dng  been  assimied  by  Acinetina.  This  occurred 
even  when  great  pains  were  taken  to  isolate  a  certain  number  of  Conferva - 
filaments  richly  covered  ^vith  Vaglnicolce,  and  to  place  them  in  pui'e  spring- 
water,  so  as  to  avoid  the  introduction  of  other  colonists.  That  the  Aciiietce 
were  derived  from  the  Vaglnicolce,  a  comparison  of  the  structure  of  the  two 
will  indicate.  The  contracted  body  of  the  Vaginicola  may  be  recognized  in 
the  Acineta  detached  from  the  bottom  of  its  sheath  and  raised  to  the  upper 
pari,  which  it  completely  fills, — the  mouth  of  the  sheath  having  previously 
been  bent  inwards  over  it  as  a  cover,  and  a  layer  of  gelatinous  matter  poured 
out  to  bind  the  two  together.  The  outermost  parts  of  the  roof-like  cover 
project  freely  above  tliis  layer,  and  are  traversed  by  several  radiating  folds  or 
fissures.  The  clearest  notion  of  the  transformation  efi'ected  is  obtained  when 
we  can  look  down  upon  the  top  suriace  of  the  capsule,  by  getting  the  axis 
perpendicular  to  the  eye. 

The  contained  body  is  closed  in  on  all  sides  ;  and  its  contents  are  substan- 
tially the  same  as  those  of  the  body  of  the  Vaginicola  (XXYII.  12),  with 
numberless  fine  granules,  and  sometimes  with  a  preponderating  number  of 
large  granules  scattered  through  them,  rendering  the  body  opaque  and  of  a 
greyish-yellow  coloiu-.  There  is  likewise  a  similar  roimd  contractile  space ; 
but  instead  of  a  band-Hke  nucleus,  there  is  a  rounded  one.  This  diff'erence 
in  respect  of  the  nucleus  is  not  important,  inasmuch  as  its  length  varies 
greatly  in  Vaginicola  according  as  the  animal  is  extended  or  in  a  contracted 
state, — being  in  the  latter  much  shortened  or  merely  elongated- oval,  whilst 
in  the  former  its  length  exceeds  two  or  three  times  its  width.  Hence  it  is  m 
no  way  remarkable  that,  in  the  very  contracted  condition  of  the  encysted  and 
Acinetiform  state,  the  nucleus  should  be  veiy  much  shortened  and  rounded, — 
a  change  which  analogy,  indeed,  -with  various  encysted  animals  would  lead 
us  to  anticipate. 

From  the  upper  surface  of  the  encysted  body  Yeiy  many  bristle-Hke 
tentacles  with  knobbed  ends  are  given  off,  which  penetrate  the  gelatinous 
layer  through  the  fissures  in  the  cover  of  the  sheath,  and  outspread  them- 
selves in  a  radiating  manner.  These  tentacles  are  for  the  most  part  straight, 
and  slowly  extend  and  retract  themselves  in  length.  Pressure  causes  theii- 
contraction,  and  huddles  them  together ;  but  they  are  not  entirely  withdi-awm. 
Some  smooth  Acinetiform  specimens  are  met  with,  which  may  be  considered 
to  be  in  an  earlier  stage,  and  similar  to  the  incomplete  Acineta  of  Epistylis 
plicatilis. 

The  origin  of  the  Acinetce  from  Vaginicola  is  further  substantiated  by  the 
relative  dimensions  of  the  two.     Thus  Vaginicolce  were  foimd  on  Conferva; 


0¥  THE  PROTOZOA. CILIATA.  363 

having  sheaths  betwixt  ■^"'  and  -^"'  in  length ;  those  most  common  were 
from  ^ij'"  to  ^"'  in  length  and  J-g-'"  in  width.  The  height  of  the  cap- 
sule of  the  Acineta  was  from  -^"'  to  -^"',  and  its  width  not  much  less. 
Moreover,  intennediate  phases  between  Vaginicola  and  Acinetina  were  met 
with, — as,  for  instance,  capsules  occupied  anteriorly  by  the  contracted  body, 
which  still  exhibited,  upon  being  moved  up  from  the  bottom  of  the  case, 
the  posterior  annular  furrow  and  traces  of  the  ciliary  wreath  previously 
existing,  and  had  its  anterior  half  enveloped  in  a  gelatinous  lamina,  uniting 
it  to  the  inner  surface  of  the  sheath,  which  was  at  one  time  more,  at  another 
less,  incui'ved  upon  the  animal,  but  had  as  yet  not  been  converted  into  the 
peculiar  pent-house-like  cover. 

The  metamorphosis,  therefore,  of  a  Vaginicola  into  an  Acineta  may  be 
thus  explained.  The  animacule  is  in  the  fii'st  place  contracted  in  the  ordi- 
nary manner ;  it  then  developes  its  posterior  fiuTow  and  ciliaiy  wreath 
(XXYII.  11),  and,  detaching  itself  from  the  bottom  of  its  sheath,  rises  to  the 
upper  part,  which  it  entii^ely  fills  and  closes  up.  From  this  time  the  rotary 
apparatus  and  digestive  tube  dLsappear  by  absorption  ;  the  excretion  of  the 
gelatinous  matter  from  the  fore  part  ensues,  and  fixes  the  animal  in  its  posi- 
tion, while  its  tendency  to  fall  to  the  bottom  of  the  case,  and  to  contract, 
draws  inwards  the  mouth  of  the  case,  and  completes  its  enclosure  within  a 
shut  sac  or  capsule  (XXYII.  12).  The  contractile  tendency  of  the  body 
still  continuing  to  operate,  brings  about  a  narro^^ing  of  the  anterior  part, 
and  with  this  a  consequent  elongation  of  the  sheath ;  in  this  way  an  ex- 
planation may  be  given  of  the  veiy  long  specimens  frequently  encomitered. 
The  extrusion  of  the  tentacles  is  an  after-occiu-rence  (XXYII.  13). 

The  complete  Acineta  can  entangle  smaU  Infusoria  with  its  tentacula, 
which,  by  their  crossing  and  retraction,  draw  the  captured  particles  to  the 
siuface,  where  probably  their  nutritive  matters  are  absorbed  through  it; 
at  aU  events,  no  food  or  foreign  particles  are  seen  in  the  interior. 

Stein  next  attempts  the  identification  of  this  Acineta  of  Vaginicola  crystal- 
Una  with  the  Acineta  mystacina  of  Ehrenberg,  and  in  a  subsequent  paj)er 
proceeds  to  show  that  it  developes  within  itself  a  ciliated  embryo.  Amid 
many  Acinetce,  he  discovered  some  bearing  a  clear  oval  or  roimded  cyst,  or, 
less  commonly,  several  such,  upon  the  surface  of  the  enclosing  Hd ;  where  there 
Avas  a  plm-ality,  they  were  evidently  in  difi'erent  stages  of  development.  The 
cyst  contained  a  sharply-defined  Infusorial  being,  of  a  homogeneous  finely- 
granular  substance,  and  having  an  actively-pulsating  sac.  At  first  Stein 
imagined  these  might  be  animalcules  casually  afiixed  to  the  Acineta? ;  but  fur- 
ther obsei-vation  proved  their  organic  connexion  with,  and  derivation  from  it. 

The  cyst-walls  were  internally  soft  and  gelatinous,  and  their  substance 
continuous,  through  the  fissm-es  of  the  cover,  with  the  gelatinous  layer  of  the 
Acineta,  of  w^hich  they  might  be  more  correctly  represented  pouches  or 
diverticula.  The  appended  animalcule  is  not  a  bud  produced  from  the 
Acineta-hodj ;  for  it  is  never  found  in  organic  connexion  with  it,  but  un- 
doubtedly has  its  origin  as  a  germ  within  it,  and  makes  its  way  outwards. 
In  fact,  it  is  developed  from  the  rounded  nucleus  by  its  elongation  and  sub- 
sequent transverse  fission.  The  yoimgest  cysts  are  round  or  shortly  oval, 
and  have  no  other  indication  of  life  and  movement  than  that  exhibited  by  the 
contractile  space.  In  the  next  stage  they  are  sHghtly  emarginate  at  one 
end  and  stiU  motionless,  whilst  in  the  oldest  the  fissure  or  emargination 
extends  deeply  into  the  interior  in  a  curved  manner,  and  veiy  clearly  exhibits 
a  number  of  vibratile  cilia.  In  this  mature  state  they  enjoy  considerable 
locomotive  powers  within  their  capsule,  and  recall  in  their  form  that  of  con- 
tracted Vorticelliaa.  Thus,  at  their  fore  part  they  present  a  rounded  ciliated 


364  GENEEAL  HISTORY  OF  THE  INFIJSOEIA. 

lobe,  resembling  somewhat  a  retracted  rotary  organ,  Avhilst  the  fissure  ex- 
tending inwards  indicates  the  alimentary  tube. 

There  is  yet  another  apparent  mode  of  embryonic  development  in  the 
Acinetce  of  VorticelUna  described  by  Stein,  which  occuiTed  in  some  specimens 
not  provided  with  tentacles.  In  place  of  these,  one  or  two  short  closed 
tubular  processes  extended  from  the  fore  part  of  the  animalcule;  of  the  usual 
granular  contents  scarcely  a  trace  remained ;  and  the  nucleus  and  contractile 
space  had  entirely  vanished.  The  membrane  of  the  enclosed  body,  thus 
deprived  of  its  ordiuary  constituents,  contained,  in  their  room,  six  elongated- 
oval  cell-like  bodies,  J^'"  long,  w^hich  seemed  to  have  been  developed  at 
the  cost  of  the  contents  of  the  original  Acineta.  These  structures  had  a 
sharp  outline,  and  contained  a  coarse  granular  substance  and  a  contractile 
sac.  They  seem  to  develope  into  embryos  ;  for  in  one  case  a  ciliated  furrow 
was  observed,  assimilating  the  being  to  the  more  usual  embryos  of  the 
Acinetce.  Probably  the  ^cmefa- condition  of  the  Vag'inkola  is  terminated 
in  this  manner,  after  developing  for  a  period  embryos  according  to  the  plan 
above  mentioned,  by  the  final  breaking  up  of  the  nucleus  into  several  large 
germs. 

In  addition  to  the  species  described.  Stein  believed  he  made  out  the 
Acineta-^i?iiQ  of  several  other  species  of  Vorticella,  of  EpistiiVis,  and  Oj^ercu- 
laria  (XXX.  1-4),  as  well  as  of  ZootJiamnmm,  Ophrydimn  (XXX.  5-8),  and 
Sph'ocliona  (XXX.  18-26).  However,  sufficient  details  have  been  given  to 
illustrate  the  presumed  fact  in  the  developmental  histoiy  of  the  Ciliated  Pro- 
tozoa ;  and  we  must  refer  those  of  our  readers  desii'ous  of  more  fully  testing 
the  views  of  that  most  excellent  observer,  to  his  often- cited  work,  '  Die 
Infusionsthiere  auf  ihre  Entwdckelungsgeschicte,'  Leipzig,  1854.  More- 
over, the  several  new  forms  of  Acinetina  he  has  pointed  out  A\all  be  found 
referred  to  in  the  general  histoiy  as  well  as  in  the  systematic  views  of  that 
group. 

It  is  now  incumbent  on  us  to  review  the  opinions  of  other  naturalists  upon 
this  remarkable  and  interesting  hypothesis.  A  few  have  accepted  it,  among 
whom  are  Mr.  Busk  (as  we  gathered  from  his  lectures  at  the  College  of 
Sui'geons  in  1857)  and  Mr.  Carter.  The  latter  has  the  following  remarks 
on  the  subject  {A.  N.  H.  1856,  xviii.  p.  237) : — "I  could  not  discover  an 
elongated  nucleus,  as  Steiu  has  figiured,  in  the  Amoehce  and  Acinetce,  which  I 
saw  developing  young  VorticeUce,  the  fonner  in  plurality  (one  to  three)  and 
the  latter  singly  :  if  present  in  the  Amoebous  form,  it  was  circular,  and  if  in 
the  Acinetce,  undistinguishable  from  the  general  '  granulation.'  Again,"  he 
goes  on  to  say,  "  where  are  these  transformations  to  end  ?  Into  what  kind 
of  Rhizopods  do  the  sheathed  VorticeUce  pass  ?  How  many  of  the  fresh- 
water Bhizopocla  are  alternating  forms  of  VorticeUce  ?"  At  the  time  of  his 
writing  the  above,  Mr.  Carter  had  not  seen  Stein's  latest  work,  which  would 
have  resolved  some  of  the  doubts  and  queries  expressed.  Thus,  the  Gennan 
naturalist  finds  the  nucleus,  if  elongated  and  band-Like  in  the  encysted  being, 
to  become  orbicular  or  oval  when  in  an  ^mie^a-state,  and  points  out  that  acetic 
acid  wiU  reveal  this  organ  when  obscui-ed  by  the  granules  of  the  interior. 
Moreover,  his  later  researches  have  been  extended  to  sheathed  VorticelUna 
or  Ophryclina — for  instance,  to  Vaginicola,  of  which  we  have  given  the  par- 
ticulars. However,  it  is  very  important  to  obtain  Mr.  Carter's  statement 
that  he  has  seen  young  VorticeUce  developed  from  Acinetce  and  Amoehce, — in- 
tending by  the  latter,  we  apprehend,  Acinetce  without  tentacles  and  capsule, 
and  not  the  simple  Amoehce  commonly  understood  by  that  term. 

The  objectors  to  the  hypothesis  are  by  far  the  more  numerous.  The  emi- 
nent physiologist  .Johannes  Midler,  to  whom  Stein  showed  ActinopTirys  and 


OF  THE  PKOTOZOA. CILIATA.  365 

Podoplirya  developing  embryos,  could  not  agree  with  the  conclusion  the  latter 
arrived  at  (viz.  that  they  became  VorticeUce),  but  was  more  disposed  to  believe 
that  they  relapsed  into  Acinet<x.  Ehrenborg  (Ueber  die  FormbestdndigJceit 
mid  den  Enhvicltehmgshreis  der  organisclien  Formen,  Berlin,  1852,  at  pp.  23, 
24,  and  34)  attributes  the  theory  to  erroneous  and  hasty  observation.  The 
supposed  embryo  of  Acineta  is,  to  his  apprehension,  simply  a  Tricliodina 
which  has  been  swallowed.  To  these  strictures  Stein  replies  that  the  Acineta - 
bodies  have  no  mouth,  that  they  never  contain  any  foreign  matters  taken  as 
food,  and  that  no  more  than  one  Tricliodina  appears  in  them  at  a  time,  al- 
though many  may  live  around  them,  and  several  would,  no  doubt,  if  taken 
as  food,  be  often  found  together  in  the  interior.  It  is,  moreover,  to  be  noted, 
that  Acineta  collected  from  the  most  different  locahties  contained  the  self- 
same Trichodi na -torm,  and  that  such  forms  occurred  in  sparing  number. 
Again,  it  must  not  be  forgotten  that  the  embryo  may  be  watched  in  active 
movement  within  the  Acineta  for  the  space  of  an  hour,  whereas  Infusoria  swal- 
lowed by  other  animalcules  are  speedily  reduced  to  a  state  of  rest  and  de- 
stroyed. Lachmann  rejects  the  hj^oothesis,  and  gives,  in  much  detail,  his 
reasons  for  so  doing.  At  the  same  time  he  confirms  the  fact  of  "  the  forma- 
tion of  embiyos,  not  only  in  many  Acinetina,  but  also  in  numerous  other  In- 
fusoria "  (A.  N.  H.  1857,  xix.  p.  232),  and  attests  the  fact  of  the  nucleus 
being  primarily  concerned  in  this  act  of  development,  adding  some  particulars 
which  require  to  be  recorded.  '^  The  nucleus,"  he  writes  (loc.  cit.),  "  is 
usually  seen,  first  of  all,  to  divide  into  two  or  more  parts,  when  the  same 
processes  take  place  in  one  or  several  of  these  parts,  which  in  other  cases 
occur  in  the  undivided  nucleus.  Upon  or  in  the  wall  of  the  nucleus,  or  of 
one  of  its  products  of  division,  we  now  sometimes  perceive  small  round  glo- 
bules, which  increase  in  size,  finally  acquire  a  contractile  vesicle,  and  become 
converted  into  embryos  ;  these  at  last  become  furnished  with  cilia,  escape  out 
of  the  parent  animal,  and  swim  about  freely,  generally  in  a  form  more  or  less 
differing  from  that  of  the  mother.  Very  clifi'erent  numbers  of  embryos  may 
be  formed  in  one  section  of  the  nucleus ;  in  the  same  species  we  sometimes 
find  many,  and  sometimes  only  one  embryo  formed  in  it ;  and  an  embryo 
which  has  been  developed  alone  in  a  fragment  of  the  nucleus  is  usually  as 
large  as  all  the  embryos  formed  in  a  similar  fragment  which  has  developed 
many  of  them  taken  together. 

"  The  true  import  of  the  nucleus,  of  coiu^se,  is  not  decided  by  this  state- 
ment ;  [we  cannot  say]  whether  it  is  to  be  regarded  as  a  germ-stock,  in 
which  germs  are  formed  asexually,  as  an  ovaiy,  in  which  the  ova  are  de- 
veloped at  the  same  time,  or,  in  accordance  with  Focke's  views,  as  a  uterus, 
in  which  the  ova  or  germs  formed  in  another  place  (perhaps  in  the  nucle- 
olus ?)  are  further  developed. 

"  The  fate  of  the  embryos  which  are  unlike  their  parents  after  their  birth 
is  stiU  unknown  in  most  cases." 

Perty  displays  distinct  opposition  to  Stein's  views,  but  has  not  thoroughly 
examined  them,  contenting  liimself  with  an  occasional  critique  in  passing. 
For  instance,  he  states  that  those  miniature  beings  regarded  as  the  brood  of 
Vorticella,  both  by  Stein  and  Ehrenberg  (see  p.  357),  are  in  his  opinion  no  more 
than  specimens  of  Cercomonas  truncata  (Duj.).  Again,  he  remarks,  Epistylis 
anastatica  is  very  rare  at  Berne  ;  and  the  Tricliodina  grandinella,  which  Stein 
represents  to  be  its  embryo,  is  very  common  in  every  collection  of  water  ; 
also  Vorticella  microstoma  is  most  abundantly  distributed,  but  its  supposed 
metamorphie  condition,  viz.  Podophrya,  very  uncommon.  Respecting  the 
latter  animalcule,  and  likewise  Actinoplirys,  he  adds  an  observation  of  his 
own,  which  convinced  him  of  the  reproduction  of  these  animals  by  minute 


Ii6(i  GENERAL  HISTORY  OF  THE  INFrSORIA. 

internal  germs,  which,  wlien  set  free,  immediately  assumed  the  special 
characters  of  theii'  parents  (Kleinste  Lehenfonn.  p.  74). 

To  Dr.  H.  Cienkowsky  we  owe  the  latest  examination  of  this  subject 
(J.  M.  /S.  1857,  p.  96).  He  rejects  Stein's  theory  because,  instead  of  finding 
Podophrya  fixa  in  company  "with  VorticeUa  microstoma,  he  met  with  it  in 
great  abundance  along  with  multitudes  oi  Styhnycliia  mytUiis  and  St.  pustu- 
lata.  Ha\^ng  watched  its  process  of  encysting,  he  felt  ''  imable  to  adopt 
Stein's  view,  that  the  Poclophryce  are  enclosed  in  a  membrane  of  which  the 
slender  peduncle  is  simplj^  a  tubular  process."  In  fact,  he  noticed  cysts  in 
which  the  original  slender  peduncle  was  appended  to  the  sacculate  envelope. 
He  also  traced,  step  by  step,  from  Podophryce,  the  derivation  of  the  supposed 
transitional  stages  between  Vorticella-cjfits  and  Podopliryce,  and  asserts 
'^  that  they  are  most  certainly  not  metamorphosed  VorticeJIa-cjats,  but  the 
commencement  of  the  encysting  of  Podophryce.  Podoplivya-:  are  not  formed 
out  of  them ;  but,  on  the  contrary,  from  ihe.  latter  arise  the  forms  above 
described,  which  Stein  looks  upon  as  Podophryce  remaining  at  an  early  stage 
of  development.  The  metamorphosed  contents  of  older  Vorficella-Qjsts,  re- 
garded by  Stein  as  the  first  commencement  of  the  formation  of  a  Podo- 
phrya, indicate,  according  to  what  I  have  seen  in  other  infusorial  cysts, 
and  to  what  Stein  himself  states  with  regard  to  VorticeUa  microstoma,  the 
commencement  of  the  breaking  up  of  the  entire  contents  into  numerous 
smaller  '  swarm  '-cells." 

Dr.  Cienkowsky's  next  proceeding  was  to  show  the  relations  of  the  motile 
embryo  developed  from  the  Podophryean  animalcule  Stein  met  with.  He 
encoimtered  numerous  Acinetce  precisely  like  those  figiu'ed  by  Stein.  "  Most 
of  these  Acinetm  were  ^vithout  peduncles,  and  had  no  limitary  membrane, 
although  numerous  specimens  might  be  seen  with  a  short  peduncle  and 
imbedded  in  a  mucoid  thick  envelope  ;  and  this  was  especially  observed  when 
the  Acinetce  had  lived  for  about  a  week  on  the  object-glas.^s  (XXIII.  33-39). 
Although  num.erous  points  of  relation  exist  between  these  Acineta-iovm^, 
and  Podoplirya  fixa  (Ehr.),  I  am  nevertheless  unable  to  determine  whether 
thej^  should  be  regarded  as  identical,  or,  with  Stein,  whether  Podophrya  and 
Actinophrys  should  be  considered  as  the  extreme  hnks  in  the  morphological 
cycle  of  one  and  the  same  species  (Stein,  he.  cit.  p.  143).  The  peduncle  of 
an  Acineta  is  a  tubular  elongation  of  the  enveloping  membrane,  whilst  in 
the  mombraneless  Podophrya  it  is  an  independent  formation.  ^\Tien  the 
Podophryce  are  left  in  water  for  a  fev,'  days  upon  the  object-glass,  they  form 
the  ver}'  characteristic  pedunculate  cysts ;  but,  under  the  same  conditions,  I 
have  never  been  able  to  follow  the  Acineta-ioTm^  now  in  question  to  the 
formation  of  cysts  ;  the  former  multiply  by  division,  whilst  in  the  Acinetce 
I  have  never  noticed  the  occiUTence  of  that  process.  "What  Stein  describes 
as  Actinophrys  is  really  a  non-pedunculate  Acineta  ;  the  Actinophryce  have 
no  tentacles,  but  setae,  though  perhaps  occasionall}^  some  of  these  setce  are 
capitate.  In  almost  every  specimen  of  the  Acinetce  in  question  might  be 
seen  rotating  a  romid  or  oval  embryo,  of  various  size  and  position,  with 
one  or  two  contractile  spaces.  This  embryo  slowly  approached  the  wall  of 
the  Acineta,  caused  it  to  protrude  a  little  outwards ;  and  after  remaining 
for  a  short  time  quiescent,  it  slowly  made  its  way  through  the  waU  (XXIII. 
41),  and  quitted  the  parent  site  with  the  rapidity  of  hghtning  when  it  had 
freed  about  half  of  itself.  This  rapidity  was  so  great,  that  the  course  could 
not  be  traced  mth  a  magnifjdng  power  of  170  diameters.  About  five  minutes 
elapsed  from  the  commencement  of  perceptible  motion  to  the  complete  libe- 
ration of  the  embryo  ;  and  on  many  occasions  I  saw  two  rotating  embryos 
liberated  in  succession.     When  the  embryo  is  half  out  of  the  parent-cyst, 


OF  THE  PROTOZOA, CILIATA.  367 

a  transverse  ring  of  very  fine  vibratile  cilia  may  be  perceived  at  a  short 
distance  from  its  summit." 

This  rapidly- mo\dng  embryo  was  followed  in  its  course,  under  "  the  mi- 
croscope, and  was  seen  to  traverse  "  the  di^op  of  water  from  one  side  to  the 
other,  in  divers  straight  and  imdulating  lines,  as  quick  as  Hghtning.  Upon 
meeting  a  mass  of  mucus  on  the  edge  of  the  drop,  it  bounced  back  again,  re- 
peating the  manoeuvre  on  each  occasion  of  the  same  kind  ;  sometimes,  though 
more  rarely,  the  movement  was  circular,  around  the  margin  of  the  drop. 

''  Judging  from  what  I  had  noticed  in  the  division  of  the  PodopJiryce,  I 
expected  that  the  movement  would  not  be  of  long  duration.  But  after  a 
continuous  observation,  for  fully  five  hours,  of  the  active  motions  of  the  tiny 
brilhant  point,  a  determination  of  blood  to  the  head  obliged  me  to  desist. 

"  A  fresh  drop  of  the  infusion,  in  which  two  embryos  were  in  active  mo- 
tion, was  observed  at  intervals  of  a  quarter  of  an  hour.  At  the  end  of  five 
hours,  the  rapidity  of  the  movement  was  notably  diminished — it  became  tre- 
mulous, and  then,  perhaps,  for  a  time,  as  rapid  and  energetic  as  before.  I 
now  placed  the  object  under  the  compound  microscope,  and  continued  my 
observation  of  the  indefatigable  embr^'o  for  another  quarter  of  an  hour  ;  the 
embryo  became  stationaiy.  I  waited  with  drawn  breath  what  would  come 
next :  its  form  from  oval  became  spherical ;  at  the  border  appeared  short, 
thick,  equidistant  rays,  which,  after  a  wliile,  were  developed  into  elongated, 
capitate  tentacles  ;  the  contractile  space  was  visible  ;  and  I  could  no  longer 
doubt  as  to  the  Acineta-ndituxe  of  the  creature  (XXIII.  42,  43).  This  obser- 
vation was  twice  repeated. 

*'  It  can,  therefore,  no  longer  be  doubted  that  from  the  Acineta-emhvjo, 
after  a  prolonged  motile  stage,  another  Acineta  is  formed.  My  observations 
do  not,  of  course,  show  that  it  is  impossible  that  the  motile  Acineta-emhvyo 
should  be  transformed  into  a  VorticeUa,  and  a  VorticeJla-Qj^tmiQ  an  Acmeta  ; 
but  the  field  of  possibilities  is  very  wide  ;  everything  is  possible  if  it  only  be 
founded  on  facts.  I  behove,  therefore,  that  it  may  justly  be  concluded  that 
Stein's  Acineta  doctrine,  as  concerns  VorticeUa  microstoma  (Ehr.),  must  be 
regarded  as  hypotheticcd ,  and  not  based  upon  facts." 

Lachmann  and  Claparede  have  jointly  examined  into  the  facts  and  appear- 
ances upon  which  Stein's  hypothesis  is  based,  and  have  presented  an  abstract 
of  their  views,  which  are  entirely  adverse  to  it,  in  the  AnnaJes  des  Sciences 
Naturelles,  1858,  in  anticipation  of  the  publication  of  their  essay,  to  which 
the  French  Academy  awarded  the  first  prize  for  original  researches  into 
the  development  of  Infusoria.  They  state  that  they  have  witnessed  the 
development  of  embryos  in  many  other  Acinetina  besides  those  recognized 
by  Stein :  that  the  embryos  of  difi'erent  species  vary ;  that  the  tentacles 
of  Acinetina  are  suctorial  and  active  in  seizing  food,  which  is  absorbed 
with  avidity  into  the  interior ;  and  that  the  internal  organization  of  those 
animalcules  is  in  all  probability  more  elaborate  than  Stein  supposed. 

The  appearance  of  the  joint  essay  on  the  development  of  the  Infusoria,  by 
the  gentlemen  mentioned,  as  well  as  of  that  by  Lieberkiihn,  which  shared  in 
the  prize  ofi'ered,  will  be  anticipated  with  much  eagerness  and  pleasure  by 
all  naturahsts  who  feel  how  obscure  and  confused  is  the  present  state  of  in- 
formation on  the  subject. 

At  the  present  time,  we  may  say  that  Stein's  hypothesis  of  the  transform- 
ation of  Ciliated  Protozoa  (or,  more  strictly,  of  the  VorticelUna  and  Ophry- 
dina,  to  which  alone  it  has  been  sought  to  refer  it  by  observation)  remains 
unproven  ;  yet  doubtless  it  is  a  step  in  the  right  direction  to  arrive  at  a  know- 
ledge of  the  true  generative  process  of  these  animalcules,  and  has  ah^eady  proved 
the  development  of  ciliated  embryos  in  Aciyietina  and  in  various  Ciliata. 


368  GENERAL  HISTOEY  OF  THE  INFUSORIA. 

The  history  of  the  metamorphoses  of  Trklioda  Li/ncens  recounted  bj'  M. 
Jules  Haime  {Ann.  d.  S.  N.  3  ser.  xix.  p.  109)  calls  for  notice  in  this  place, 
although  we  are  not  disposed  to  assign  it  much  value,  inasmuch  as  some 
of  the  phenomena  stated  are  very  extraordinaiy,  are  unsupported  by  any 
parallel  facts,  and  are  in  actual  opposition  to  those  best  ascertained  respect- 
ing the  organization  and  functions  of  the  Ciliata.  We  would  especially  direct 
attention  to  the  statement  of  the  exudation  of  sarcode,  and  the  consequent 
reduction  of  size,  as  a  necessary  step  in  the  developmental  phases, — an  occur- 
rence, in  oiu-  belief,  without  analogy  and  quite  anomalous. 

He  first  asserts  that  ''  O.vijt ri cha  (Ehr.)  is  a  laiTal  phase  of  Triclioda  Lyn- 
ceus,  and  next  that,  on  its  fissiparous  di\ision,  generally  one  of  the  two  seg- 
ments produced  assumes  a  globular  form,  losing  almost  all  its  a23pendages, 
both  cilia  and  setas,  and,  at  the  same  time,  gives  exit  to  successive  portions 
of  its  sarcode,  so  that  vacuoles  multiply  in  its  interior.  At  this  stage  a  ge- 
latinous cyst  is  excreted  around  it  which  ultimately  hardens  into  a  mem- 
branous envelope.  In  a  short  time  the  contents  of  the  cyst  shrink  from  the 
cyst-walls  and  leave  a  space  around  them,  when  ciliary  movement  appears 
at  one  part,  and,  a  further  escape  of  granular  sarcode  having  taken  place 
through  the  cyst- wall,  the  figure  becomes  more  or  less  modified.  Two  por- 
tions are  now  distinguishable  within  the  cyst — a  ciliated  embiyo  and  a  mass 
of  efiete  granular  matter ;  and,  as  time  elapses,  the  former  seems  to  grow 
at  the  expense  of  the  latter,  and  eventually  makes  its  escape  from  the  nearly- 
emptied  cyst.  The  freed  animalcule  is  not  at  first  very  diff'erent  in  appearance 
from  the  parent  Oxytricha,  although  only  about  two-thirds  its  diameter ;  but 
ere  long  it  developes  itself  into  a  veiy  difi'erent  l)eing.  In  so  doing,  it  first 
exudes  some  more  of  its  substance,  then  produces  numerous  short  stiff"  setae 
to  serve  it  as  feet,  acquires  a  hard  integ-umcnt  in  the  form  of  a  shield,  or 
carapace,  and  forms  a  mouth,  in  the  form  of  a  slit  on  one  side,  and,  in  front 
of  this,  a  gyrating  filament  to  produce  a  current  for  the  introduction  of 
food.  In  this  transformed  being  the  Aspidisca  (Ehr.)  is  recognizable,  having 
a  very  much  smaller  size  than  the  original  Oxytriclia.  The  reversed  course 
of  development,  viz.  that  of  Aspidisca  into  O.vytricha  has  not  been  fol- 
lowed ;  but  it  may  be  conjectured  that  a  sexual  process  is  interposed,  pro- 
bably in  connexion  with  other  metamorphoses." 

Before  taking  leave  of  the  subject  of  reproduction  among  the  Ciliata,  it 
is  important  to  add  a  statement  made  by  Lachmann  in  his  excellent  and 
oft-quoted  essay  (p.  239).  He  writes — "  With  regard  to  the  peculiar  pro- 
cess of  copulation  or  zygosis  of  the  Infusoria,  as  its  object  is  still  entirely 
unknown,  I  shall  only  state  that,  except  in  the  Diatomacece  and  Desmidiacece, 
the  position  of  which  is  still  doubtful,  it  has  hitherto  been  observed  par- 
ticularly in  Actinophrys  and  Acinetina.  According  to  an  oral  statement, 
E.  Claparede  has  also  seen  Vortkellina  (especially  V.  microstoma)  in  zygosis ; 
and  I  have  twice  met  with  double  animals  of  Carcliesium,  still  sitting  upon 
a  double  stalk  and  constantly  becoming  more  amalgamated,  so  that  the 
cavities  of  both  the  fused  animals  communicated,  and  the  morsel  which  was 
passed  from  the  pharynx  of  one  animal  usually  ascended  in  the  cavity  of 
the  other,  up  to  the  lower  surface  of  its  ciliary  disk.  The  rotatory  organs 
remained  separate  ;  and  after  the  lapse  of  some  time,  the  double  animal  cast 
itself  loose  from  the  stems,  and  swam  about  for  more  than  twenty-foui'  hours 
by  means  of  a  circlet  of  cilia,  which  was  produced  around  the  rounded  hinder 
extremity  formed  by  the  coalescence  of  the  two  posterior  extremities  of  the 
individual  animals." 

Nature  or  the  Ciliated  Protozoa.  Their  Existence  as  Independent 
Organisms.    Cell  Theory  applied  to  them. — That  the  bein2:s  we  have  com- 


OF  THE  PROTOZOA. CILIATA. 


369 


i 


prehended  under  the  appellation  Ciliated  Protozoa  are  indubitably  animals, 
has  never  been  called  in  question  ;  nevertheless  their  claim  to  be  considered 
independent  organisms  has  been  challenged  by  a  few  naturalists,  who  insist 
on  their  being  generally  nothing  more  than  phases  of  development  of  animals 
more  or  less  elevated  in  the  scale.  These  objectors  have,  however,  hitherto  failed 
to  produce  sufficiently  direct  and  exact  observations  in  proof  of  this  general 
assertion,  which  rests  mainly  upon  presumed  external  resemblances,  and  on 
analogy  with  many  of  the  inferior  animals,  among  which  the  so-called 
^'  alternation  of  generations  "  is  the  rule.  In  the  foregoing  pages  there  is 
certainly  sufficient  evidence  that  some  Infusorial  forms  are  merely  stages  of 
development  of  others ;  and  nothing  is  more  probable  than  that  some  may 
similarly  be  phases  of  animals  belonging  to  other  classes  than  the  Ciliata ; 
yet,  on  the  other  hand,  the  independent  character  of  several  families  (for 
example,  of  Vortlcellina,  Ophrydina,  and  Colejpina)  has  not  been  at  all  shaken 
by  the  researches  of  naturalists. 

There  is,  we  believe,  a  trae  typical  organization  appertaining  to  the  Ciliata, 
of  a  distinct  character  fi'om  that  of  other  animal  organisms,  and  inconverti- 
ble. It  may  be  more  or  less  perfected,  or  more  or  less  degraded,  and  may, 
in  the  process  of  development,  be  put  in  abeyance  for  a  time,  though  not 
replaced  by  another ;  and  under  this  impression,  Stein's  views  of  Acineti- 
form  metamorphosis  have,  to  our  mind,  an  air  of  improbability. 

The  very  distinguished  naturalist  M.  Agassiz  stands  among  the  foremost 
in  advancing  the  sweeping  conclusion,  that  the  Ciliated  Protozoa  have  no 
existence  as  a  class.  Most  of  the  Enterodela  of  Ehrenberg,  he  says  (A.  N.  If. 
1850,  vi.  p.  156),  "  far  from  being  perfect  animals,  are  only  germs  in  an 
early  stage  of  development.  The  family  of  Vorticellce  exhibits  so  close  a 
relation  with  the  Bryozoa,  and  especially  with  the  genus  PediceUina,  that  I 
have  no  doubt  that  wherever  Bryozoa  should  be  placed,  Vortkella  should 
follow,  and  be  ranked  in  the  same  division  with  them.  The  last  group  of  In- 
fusoria— Bursar la,  Paramecium,  and  the  like — are,  as  I  have  satisfied  myself 
by  direct  investigation,  germs  of  fresh-water  worms,  some  of  which  I  have 
seen  hatched  from  eggs  of  Planaria  laid  under  my  eyes."  In  these  statements 
Mr.  Girard  {Proceedings  of  American  Association,  1848,  p.  402)  coincides, 
and  adds  that  CoJ-poda  CucuUulus  is  one  of  the  embryonic  stages  of  fresh-water 
Plana7'ia. 

To  these  statements  it  may  veiy  fairly  be  objected,  that  the  embryonic 
animalcules  presumed  to  be  identical  with  certain  Ciliata  may  possess  merely 
a  deceptive  outward  resemblance,  and,  again,  that  in  the  case  of  the  assigned 
affinity  of  the  VorticeUina,  an  exact  comparative  examination  of  the  organi- 
zation of  this  family  with  that  of  Bryozoa  will  show  that  there  is  no  true 
homology,  but  simply  some  general  points  of  similarity,  between  them. 

When  Schleiden  and  others  unfolded  the  cell-theory  as  a  general  fact  in 
organic  beings,  attempts  were  at  once  made  to  apply  it  to  the  simplest  animal 
structures,  among  which  the  Ciliated  Protozoa  are  numbered.  The  Protozoa 
were  called  unicellular  animals ;  a  cell- wall,  more  or  less  modified,  was 
everywhere  discovered  or  supposed ;  and  the  more  solid  body,  the  testis  of 
Ehrenberg,  was  at  once  assumed  as  the  "nucleus."  This  name  we  have  for 
convenience'  sake  retained,  although  its  special  relation  with  ceU-structure 
and  the  cell-theory  cannot,  in  our  opinion,  be  sustained. 

The  cell-theory,  in  its  application  to  Protozoa,  found  a  very  able  advocate 
in  KoUiker  (J.  M.  S.  1853,  i.),  and  was  upheld  by  many  others  ;  its  simpli- 
city, and  the  generalization  as  to  structure  and  function  it  suggested,  recom- 
mending it  to  philosophic  minds.  Latterly,  however,  a  more  exact  apprecia- 
tion of  the  true  organization  and  functional  history  of  animalcules  has  caused 

2b 


370  GENERAL  HISTORY  OF  THE  INFUSORIA. 

the  abandonment  of  the  hypothesis,  the  gTeatest  names  in  microscopic  science 
having  pronounced  against  it. 

To  sum  up  the  leading  circumstances  opposed  to  the  theory  in  question. 
The  processes  of  the  surface,  both  in  variety  of  character  and  of  movements, 
are  not  paralleled  in  any  known  simple  cell ;  the  same  may  be  said  of  the 
pedicles  and  branched  stems  of  Vorticellina,  and  of  the  sheaths  of  Oplirydina : 
the  presence  of  a  mouth,  and,  according  to  the  descriptions  of  many  excellent 
observers,  of  a  discharging  aperture  or  anus,  and  the  involution  of  the  external 
siu"face  in  the  form  of  an  alimentary  tube,  are  facts  iiTeconcileable  with  the 
idea  of  a  cell.  So,  likewise,  the  beautiful  and  complicated  cihary  apparatus 
of  the  VorticeWma  and  Ophrydina — the  existence  of  cells,  or  at  least  of 
vesicles,  in  the  interior — the  reception  of  external  matters  into  the  general 
cavity,  where  they  are  either  entirely  digested  or  partially  or  wholly  extruded 
again — and,  lastly,  the  acti\dty,  persistence,  and  apparently  voluntary  cha- 
racter of  their  movements,  are  cii^cumstances  vrithout  parallel  in  the  economy 
of  simple  cells.  In  the  face  of  all  these  discrepancies  in  stnictm-e  and  func- 
tion between  the  bodies  of  Ciliated  Protozoa  and  simple  cells — closed  sacs, 
containing  a  nucleus  amid  their  protoplasmic  substance — it  appears  to  us  it 
would  be  a  mere  visionary  notion  to  insist  upon  a  homology  betwixt  the  two. 
To  conceive  such  a  thing,  the  accepted  idea  of  a  cell  must  be  set  aside,  and 
replaced  by  so  loose  and  general  a  definition  as  would  be  worthless. 

Without  quoting  their  remarks,  which  is  imcalled  for  here,  the  following 
observers  may,  among  others,  be  cited  in  opposition  to  the  hypothesis  of  the 
imicellular  nature  of  the  Cihata :  viz.  Leuckart,  Lachmann,  Claparede,  Perty, 
and  Schneider.  Our  countryman,  Mr.  Busk,  is,  as  we  gathered  from  his  lec- 
tures, to  be  reckoned  in  the  number. 

Conditions  of  Life. — Under  this  head  we  have  to  consider  the  habitats 
of  the  Ciliata,  the  usual  conditions  imder  which  they  live,  their  successive 
appearance  in  liquids,  the  influence  of  heat  and  cold,  and  of  chemical  agents 
upon  them,  and  their  probable  duration  of  life. 

The  majority  of  the  Cihated  Protozoa  are  inhabitants  of  fresh  water;  few' 
are  marine ;  or  perhaps  it  would  be  more  correct  to  state  that  few  marine 
species  are  known.  Cohn  affirms  that  fresh  water  acts  as  a  poison  and  kills 
the  marine  forms  (Entiv.  pp.  132,  133) ;  that  the  several  genera  of  Entero- 
dela  (Ehr.) — Cydidium,  Pmximecium,  Eujplota,  Oxytricha,  and  Yorticella — 
occiu'  in  water  holding  organic  matter  in  solution  or  decomposition  ;  and  that 
Stentor,  Ophrydium,  and  Loxodes  are  found  only  where  the  water  is  pure  and 
uncontaminated  with  dead  matter.  This  statement  must  not  be  taken  arbi- 
trarily ;  for  among  the  former  series,  specimens  are  constantly  seen  in  water 
free  from  appreciable  organic  impurities.  Moreover,  in  all  cases,  the  aqueous 
medium  in  which  the  Ciliata  live  must  contain  a  certain  proportion  of  organic 
materials  (either  living  in  the  tissues  of  minuter  organisms,  or  in  a  state  of 
transition,  commencing  decomposition  or  breaking  up  into  mineral  or  dead 
matter),  from  which  they  can  derive  the  elements  of  their  nutrition. 

Animalcules  indeed,  if  we  may  so  say,  stand  between  the  living  and  the 
dead,  rescuing  the  atomic  fragments  of  organic  matter  which  are  ready  to 
perish  and  to  lapse  into  the  domain  of  dead  matter.  Thus  we  find  them 
constantly  in  infusions,  either  artificially  made  by  steeping  animal  or,  more 
particularly,  vegetable  substances  in  water,  or  naturally  occurring  in  ponds 
and  ditches  containing  growing  aquatic  plants  or  theii'  detached  portions,  or 
in  the  tui'fy  hollows  of  commons  and  bogs.  At  times,  indeed,  the  water  in 
which  they  occur  appears  to  the  eye  almost  pure,  and  free  from  extraneous 
matters ;  but  a  closer  examination  will  prove  it  to  be  inhabited  by  multitudes 
of  monadiform  existences,  of  minute  plants,  Desmidiece,  Diatomece,  Nostochinece, 


OF  THE  PROTOZOA. CILIATA.  371 

Confervce,  and  Algce,  which  are  difFiised  throughout,  or  float  upon  the  surface, 
or  form  a  stratum  at  the  bottom. 

The  attached  forms  find  appropriate  habitats  upon  the  stems  of  aquatic 
plants,  and  very  commonly  upon  the  surface  of  various  animals  living  in 
water ;  for  instance,  on  the  shells  of  Mollusca,  such  as  the  water- snails,  and 
on  the  surface  of  the  Entomostraca.  A  few  species  find  a  suitable  locality 
within  the  interior  of  larger  animals,  of  which,  therefore,  they  are  esteemed 
the  parasites, — a  fact  illustrated  in  the  genus  Bursar  la.  This  subject  of  the 
habitats  of  the  several  genera  needs  not  here  to  be  enlarged  upon,  since  it 
recurs  again  and  again  in  the  generic  and  specific  descriptions  of  the  systematic 
division  of  our  work. 

The  Ciliata  do  not  so  frequently  constitute  the  coloiuing  ingredients  in 
water  as  do  the  Phytozoa.  Nevertheless  there  are  several  species  which 
make  their  presence  known  by  their  colour,  either  when  collected  in  a  stratum 
upon  the  surface  of  plants  or  of  the  water,  or  when  generally  diffused  in  a 
small  pool.  Thus  Stentor  iDohjmoyylms  and  Vorticella  chlorostigma  coat  the 
stems  of  aquatic  plants  green,  whilst  several  species  of  Vorticellina  cover  them 
as  with  a  bluish-milky  film,  and  Stentor  aureus  with  an  orange -coloured  in- 
duvium.  Bursaria  vernalis,  Traclielocerca  viridis,  Coleps  viridis,  Glaucoma 
viridis,  and  Paramecium  Chryscdis  are  found  dispersed  through  the  water — the 
four  fii'st  imparting  to  it  a  green,  the  last  a  milky  tint.  The  greenish  masses 
of  Oplirydium  versatile  at  times  float  on  the  surface,  driven  about  by  the 
wind,  and  at  others  are  attached  to  the  tendi'ils  of  roots  and  to  the  stalks  of 
aquatic  plants. 

The  chstinct  colours,  such  as  green,  yellowish-red,  and  orange-brown,  are 
in  all  cases,  we  believe,  not  essential  to  the  animalcules  exhibiting  them,  but 
due  to  the  food  they  swallow,  and  to  its  changes  in  course  of  digestion. 
These  changes,  as  affecting  the  colour,  have  been  illustrated  in  a  preceding  page 
(p.  310)  in  the  instance  of  Bursaria  vernalis,  for  which  the  Chilodon  ornatus 
might  have  been  substituted.  Moreover,  in  Nassula  the. reddish-blue  or  violet 
spots,  conceived  to  be  glands  by  Ehrenberg,  are  apparently  the  product  of  di- 
gested Oscillatorice  (p.  312). 

SuccEssioi^^  OF  Species. — If  a  fluid  containing  Infusoria  be  examined  from 
time  to  time  over  a  considerable  period,  it  will  be  found  that  certain  species 
disappear,  and  are  replaced  by  others  not  before  found  in  it.  This  succession 
of  forms  in  the  same  liquid  has  been  remarked  from  the  earliest  period  of 
microscopic  research,  and  has  been  the  fruitful  source  of  the  wildest  theories 
of  the  metamorphoses  of  Lifusoria.  Succeeding  animals  have  been  forth- 
with concluded  to  be  the  transformed  states  of  previous  ones,  however  wide 
the  dissimilarity  between  them :  no  intermediate  phases  or  transitional  changes 
have  been  watched;  but  the  conclusion  that  the  one  is  derived  from  the 
other,  has  been  jumped  at  without  reserve.  Some  theorists  have  even  pro- 
ceeded further,  and,  like  linger,  behoved  in  the  transformation  of  vegetable 
into  animal  hfe,  or,  like  Laurent  and  Gros,  have  imagined  the  conversion  of 
mineral  matter  into  organized  animalcules,  and  these  last  into  beings  of  stiU 
higher  position  in  the  animal  scale,  such  as  Annelida  and  Crustacea. 

A  partial  explanation  of  the  succession  of  animal  forms  in  a  collection  of 
water  is  to  be  found  in  the  following  facts : — 

First,  no  vessel  of  water  of  ordinary  dimensions  can  be  so  thoroughly  ex- 
amined but  that  some  animalcules  may  be  overlooked ;  the  same  accident  will 
happen  stiU  more  frequently  with  their  minuter  germs  or  embrj'onic  condi- 
tions, or  with  their  encysted  state.  The  earliest  phases,  again,  may,  in  their 
transient  form,  verj^  nearly  resemble  certain  known  independent  species,  and 
be  readily  mistaken  for  them,  or  even  for  encysted  simple  plants.    So,  also,  por- 

2b2 


372  GENERAL  HISTOET  OF  THE  INFUSORIA. 

tions  of  plants,  small  aquatic  animals,  organic  debris,  and  other  substances  in 
the  water  may  conceal  in  their  cavities  or  interstices  either  mature  animalcules 
or  their  immature  or  encysted  forms.  Further,  we  know  the  air  to  be  per- 
meated by  animalcular  life  ;  that  every  wind  wafts  organized  beings,  for  the 
most  part  in  an  encysted  state,  together  with  germs  and  spores,  animal  and 
vegetable,  to  and  fro ;  and  every  exposed  collection  of  water,  unless  protected 
by  the  most  careful  and  complex  contiivances,  must  perpetually  receive  fresh 
colonists.  Kow,  among  all  these  matiu'e,  encysted,  immature,  and  embryonic 
inhabitants  of  a  portion  of  water,  existing  in  it  when  first  submitted  to  obser- 
vation, or  subsequently  introduced  into  it  from  without,  there  must  neces- 
sarily be  a  constant  change  in  their  relative  abimdance,  and  even  in  their  con- 
tinued existence  in  it.  Matm-e  individuals  may  die  out,  be  devoured  by  other 
animals,  or  be  otherwise  destroyed  before  miiltipljing  themselves,  or  may, 
by  encysting  and  reproduction,  develope  beings  of  a  different  general  character, 
{^ e.  undergo  a  real  transformation;  encysted  beings  may  merge  into  hfe, 
immatui-e  and  embryonic  forms  take  on  their  perfect  conformation  ;  hidden 
organisms  may  come  out  from  their  concealment ;  or  the  new  ones  borne  by 
the  air  may  manifest  themselves ;  and  in  these  and  other  conceivable  ways 
new  series  of  inhabitants  may  make  their  appearance  on  the  scene. 

Lastly,  the  succession  of  species  is  greatly  influenced  by  the  changing  con- 
ditions of  the  water  and  its  contents,  by  atmospheric  conditions — cold,  heat, 
and  electricity,  and  the  moisture  or  dryness  of  the  air.  All  the  facts  collected 
under  the  head  of  Habitats  indicate  the  mutual  relations  between  the  appear- 
ance of  certain  animalcules  and  the  jDresence  of  particular  plants  or  even  of 
certain  animals,  or  the  existence  or  absence  of  decomposing  organic  matter. 
We  have,  moreover,  so  to  speak,  carnivorous  and  herbivorous  Ciliata,  each 
and  all  severally  requiring  their  special  nutritive  elements  in  the  water. 
From  these  circumstances  it  is  evident  that  particular  species  will  disappear 
when  the  conditions  favourable  to  them  fail,  to  be  in  all  probability  replaced 
by  others  to  which  the  change  is  favoiu^able  and  necessary ;  for  instance,  the 
vegetable  feeders  will  decrease  and  disappear  when  the  minute  plants  on 
which  they  feed  are  consumed  ;  so  those  animals  requiring  pure  water  will  die 
out  when  decomposing  organic  matters  multiply,  and  will  be  replaced  by  the 
forms  which  delight  in  their  presence,  but  have  remained  undeveloped  until 
the  conditions  favoui'able  to  their  existence  are  brought  about.  The  little 
CoJeps  (to  give  a  particular  illustration)  delights  in  the  eggs  and  contained 
substance  of  Entomostraca,  and  makes  its  appearance  in  company  with  those 
animals,  without  which  it  is  only  occasionally  seen.  And  it  remains  to  be 
noted,  that  unless  an  animalcule  is  duly  supphed  with  appropriate  nourish- 
ment, its  reproductive  powers  remain  in  abeyance,  and  consequently  its  whole 
race  may  vanish  from  this  cause. 

A  particular  example  of  the  succession  of  species  may  be  quoted  from 
Cohn's  essay  on  Eeproduction  of  Infusoria  {Zeitschr.  1851,  p.  2^'6).  In  a 
vessel  containing  decomposing  Sphogyra,  at  first  appeared  countless  speci- 
mens of  Paramecmm  Aurelia ;  these  were  replaced  by  the  Proteus  of  Baker, 
either  the  Lacrymaria  Proteus  or  the  Tracheloce7xa  Olor  (Ehr.)  ;  these  in 
their  turn  were  followed  by  ChUodon  CucuUulus,  and  after  a  few  days  by  a 
Colpoda  ;  afterwards  large  Euplotes  with  prominent  green  globules,  probably 
a  new  species,  and  lastly,  colourless  specimens  of  Euplotes  Charon  exhibited 
themselves, — all  these  species  following  each  other  in  succession  in  the  course 
of  three  weeks,  a  new  form  appearing  on  the  decline  of  a  preceding,  attaining 
its  maximum  in  number,  and  then  decreasing  in  its  tiu"n  to  make  room  for  the 
next  in  the  series.  Moreover,  this  excellent  observer  remarks  that  a  similar 
•succession  is  observed  in  the  case  of  microscopic  plants,  such  as  OseiUatoria. 


OF  THE  PROTOZOA. CILIATA.  373 

Duration  of  Life. — "What  this  may  be  among  the  Ciliata  is  little  known  to 
us.  **The  Infusoria  have  a  comparatively  long  life  "  was  one  of  the  general  facts 
enunciated  by  Ehrenberg.  ITnder  favourable  conditions  certaiu  species  have 
been  known  to  live  four  or  five  weeks.  This  applies  to  them  only  in  one  phase 
of  existence,  viz.  that  which  we  regard  as  the  normal  and  mature  one.  But 
when  we  take  into  consideration  the  encystuig-process  as  an  act  of  conserva- 
tion, we  are  compelled  to  assign  them  a  duration  of  life  of  a  very  much  longer 
range ;  for  by  its  means  the  Ciliated  Protozoa  are  preserved  in  a  quiescent, 
torpid,  or  hybemating  state,  not  only  over  periods  of  di'ought  when  the  ponds 
containing  them  may  be  dried  up,  but  also  during  the  entire  winter. 

Further,  by  the  medium  of  fission  and  gemmation,  the  existence  of  the 
animalcule  is  prolonged  or  perpetuated  thi'ough  all  the  multiplied  series  of 
di\isions  and  subdivisions  and  of  gemmation,  primary,  secondary,  and  multi- 
fold, until  the  chain  is  broken  by  a  sexual  act  of  generation,  and  the  being 
perishes  in  the  production  of  its  otEspring. 

The  resuscitation  of  Infusoria,  after  apparent  death,  forms  a  chapter  in 
Ehrenberg's  great  work ;  but  the  facts  discussed  have  little  or  no  beaiing  on 
this  group  of  Ciliata ;  and  the  marvel  formerly  attaching  to  the  subject  is  much 
diminished  by  our  knowledge  of  the  phenomena  of  encysting,  whether  for  the 
purpose  simply  of  self-preservation  or  the  carrying  out  of  the  process  of  de- 
velopment. 

IifFLrENCE  OF  External  Agents.  Heat  and  Cold. — The  Ciliata  can  sup- 
port very  considerable  variations  of  temperature.  Even  in  winter,  beneath 
the  ice,  various  species  may  be  foimd  still  living.  Ehrenberg  tells  us  that 
Vorticella  microstoma  will  live  after  being  exposed  to  a  temperature  of  8° 
Fahr.,  and  the  ice  gradually  thawed ;  in  fact,  however,  not  more  than  one  in 
a  hundred  will  survive  this  process.  Below  this  temperature  none  can  live. 
The  same  is  true  of  Paramecium  Aurelia,  Cyclidium  Glaucoma,  Glaucoma 
scintillans,  and  Colpoda  Cucullus.  When  death  is  caused  by  cold,  no  rupture 
or  injury  of  the  body  is  perceptible,  except  in  the  case  of  Cliilodon  Cucullulus 
and  some  few  other  species,  which  are  frequently  quite  disintegrated  and  dis- 
persed. Stentor  polymorphus  and  S.  Mulleri  will  not  live  many  hours  at  a 
temperature  of  9°  Fahr.  ;  and  arborescent  Vorticella,  subjected  to  the  same 
degree  of  cold,  faU  from  their  stems  and  die. 

Perty  gives  a  ILst  of  about  40  species  of  Ciliata  which  he  found  in  Switzer- 
land during  the  cold  of  winter,  beneath  the  ice  ;  we  name  a  few  as  a  guide  to 
investigators : — Coleps  hirtus  (often  without  a  shell),  C.  inermJs  ;  Oxytricha 
pellioyiella,  0.  caudata,  0.  prisca,  0.  gihha ;  Pleuronema  crassa ;  Eitplotes 
stnatus ;  Vorticella  patellina ;  Stentor  Rosellii ;  Paramecium  Colpoda,  P. 
versutum,  P.  leucas;  Trachelius  Anas,  T.  Lamella,  T.  Meleagris  ;  Trachelocerca 
Olor  ;  Glaucoma  scintillans  ;  Lacrymariarugosa  ;  EncJielys  Farcimen  ;  Cliilo- 
don Cu^idhdus  ;  Spirostomum  ambiguum  ;  Amphileptus  Fasciola,  &c. 

Ehrenberg  affirms  that  when  animalcules  are  fi"ozen  in  ice,  they  are  as  it 
were  lodged  in  a  Httle  cavity,  and  suiTOimded  by  water.  This  circumstance 
he  imagined  to  be  due  to  their  animal  heat, — an  explanation  too  improbable 
to  be  admissible ;  and,  if  the  observation  be  correct,  it  must  give  place  to  some 
other. 

Respecting  the  effects  of  cold,  it  is  a  general  law  of  the  Ciliata,  that  their 
numbers  rapidly  diminish  when  winter  sets  in,  and  that,  on  the  contrary, 
they  rapidly  augment  so  soon  as  the  warmth  of  the  sun  in  spring  manifests 
itself,  and  continue  to  increase  in  number  and  variety  until  the  height  of 
summer  is  passed. 

Their  endm-ance  of  heat  is  almost  equally  extraordinary  as  that  of  cold. 
Some  are  found  in  hot  springs  :  thus  Perty  found  specimens  in  the  hot  springs 


374  GEIfEEAL  HISTORY  OF  THE  INFUSORIA. 

of  Leuk,  at  a  temperature  of  about  80° ;  and  Ehrenberg  heated  water  gradu- 
ally to  120°  Fabr.,  when  Colpoda  Cucidlus  and  Cliilodon  Cuculhdus  survived. 

Necessity  of  Air. — The  water  which  Ciliata  inhabit  must  be  duly  aerated 
to  support  their  existence,  as  is  shown  by  the  experiment  of  pouring  a  layer 
of  oil  on  the  top  of  a  vessel  of  water  containing  them,  and  by  their  disap- 
pearance from  a  bottle  which  has  been  kept  too  long  corked. 

They  decrease  in  number  and  variety  after  water  has  been  kept  for  some 
time  in  the  house,  even  though  it  remains  sweet ;  this  is  probably  due  in  part 
to  the  more  stagnant  atmosphere  and  the  consequent  diminished  admixtui'e 
of  air  with  the  water. 

Chemical  Agents.  Electricity  and  Galvanism. — Eor  chemical  substances 
to  act,  they  must  be  soluble  in  the  water.  Sea -water  is  generally  more  or 
less  speedily  fatal  to  fresh-water  species ;  and,  on  the  other  hand,  fresh 
water  is  destructive  to  marine  species,  especially  when  the  change  of  medium 
is  sudden.  However,  some  species  are  common  both  in  sea-  and  in  spring- 
water  ;  and  there  are  others  hving  in  brackish  water  which  can  readily  ac- 
commodate themselves  to  a  change  of  habitation. 

There  are  also  substances,  such  as  sugar,  which,  although  not  in  them- 
selves poisonous,  are  damaging  to  animalcules,  probably  by  causing  an  in- 
jurious alteration  in  the  density  of  the  water.  Other  substances,  having 
active  properties  as  poisons  to  animal  life  at  large,  such  as  corrosive  subli- 
mate, strychnine,  arsenic,  and  the  like,  are  also  poisonous  to  animalcules. 
Reference  has  been  made  to  several  chemical  compounds  which,  by  reacting 
variously  on  the  tissues  of  animalcules,  are  employed  for  the  purpose  of 
demonstrating  points  in  their  organization:  such  are  acetic  acid,  alcohol, 
tincture  of  iodine,  solution  of  potassa,  &c.  The  last  acts  as  a  solvent,  caus- 
ing diffluence,  as  Mi\  Addison  pointed  out  some  years  since  (A.  iV.  H.  1843, 
xii.  p.  101). 

Of  the  effects  of  electricity,  galvanism,  and  magnetism,  we  know  little :  ex- 
periments with  these  forces  are  few  and  imperfect.  Ehrenberg  collected  the 
accoimts  of  several,  among  which  are  the  following : — A  shock  from  a  Leyden- 
jar  charged  with  twenty  sparks  from  an  electrophorus  having  a  resinous  plate 
7-|-  inches  square,  and  a  collector  5^  inches,  suddenly  killed  Stentor  niger, 
St.  aureus,  and  AnipJiilejptus  moniliger.  The  bodies  of  Ojyliryoglena  atra  and 
Stentor  polymorphus  were  entii^ely  dissipated  by  it,  as  were  also  those  of 
Epistglis  flavicans,  after  having  first  been  thi'own  from  theii'  stalks.  It 
generally  requii'ed  two  such  shocks  to  kill  the  Paramecium  Aurelia.  When 
the  electrical  current  passed  near  and  not  through  them,  their  movements  ap- 
peared unsteady.  Electricity  slowly  produced  has  a  more  powerful  effect  than 
in  the  form  of  rapid  shocks  ;  and  when  either  it  or  the  magnetic  current  de- 
composes the  water  in  which  the  animalcules  are,  then  death  is  a  necessary 
consequence. 

Mr.  Eood  {Bill.  Journ.  1853,  xv.  p.  71)  has  experimented  more  recently, 
and  states  that,  when  a  feeble  galvanic  ciuTent  is  passed  through  water  con- 
taining Paramecia,  the  animals  are  brought  to  a  stand-still,  particularly  in 
the  neighbourhood  of  the  negative  pole,  and  after  revohdng  for  a  time  on 
their  own  centres,  entirely  cease  to  move ;  ciliaiy  action  is  also  arrested,  and 
diffluence  quickly  ensues. 

On  the  subject  of  the  operation  of  chemical  reagents  on  Protozoa,  or,  strictly 
speaking,  on  Paramecia,  v^ith  which  he  chiefly  experimented,  Mr.  Rood  has 
the  following  remarks : — Alcohol  stopped  their  motion,  coagulated  their  con- 
tents so  that  they  shrunk  within  their  integument,  and  caused  speedy  death. 
Phosphate  of  soda  killed  in  a  few  minutes ;  and  Epsom  salts,  the  ammonio- 
chloride  of  mercurv,  acetate  of  lead,  and  perchloride  of  mercury  destroyed 


OF  THE  PROTOZOA. CILIATA.  6fO 

life  instantly.  Cyanide  of  potassium  did  the  same,  producing  at  the  same 
moment  ruptui-e  of  the  integument  and  the  discharge  of  the  contents.  On 
adding  a  quantity  of  oxalate  of  ammonia  to  the  water,  a  stupefying  effect  at 
once  follows,  but  after  a  few  minutes  the  animalcules  revive,  and  death  does 
not  result — at  least,  not  for  some  hours.  Likewise,  neither  ferrocyanide  of 
potassium  nor  neutral  chromate  of  potash  kills — at  least,  not  under  several 
hours.  This  last-named  fact  suggests  the  possibility  of  chemically  injecting 
or  impregnating  animalcules,  whilst  stiU  Living,  with  a  mixtm^e  of  suitable 
reagents  to  produce  coloured  precipitates  which  might  serve  in  demonstrating 
their  internal  structiu'e. 

Geographical  Distribution. — We  know  as  yet  of  no  special  laws  of  geo- 
(jrapliical  distribution  of  the  Ciliated  Protozoa  ;  and  a  long  time  must,  we 
fear,  elapse  ere  the  waters  of  the  earth  are  sufficiently  explored  to  warrant 
even  an  approximative  sketch  of  such  laws.  Wherever  on  this  globe  we 
may  seek  for  these  animalcules,  they  are,  it  seems,  to  be  found — even  the 
same  families,  genera,  and  species  ;  and  if  our  present  knowledge  leads  us  to 
define  particular  localities  for  particular  sj)ecies,  it  amounts  to  little  more 
than  stating  that  they  have  there  arrested  the  attention  of  some  observer  or 
observers,  and  have  been  overlooked  or  searched  for  at  the  wrong  season,  or 
under  unfavourable  circumstances,  in  other  places.  Por,  as  our  remarks  on 
the  succession  of  species  imply,  the  animalcules  present  in  any  collection  of 
water  one  week,  may  be  in  vain  searched  for  the  next ;  and  the  inhabitants 
of  a  pool  or  stream  of  one  season,  or  of  one  year,  may  be  exchanged  for 
others  the  next.  Although,  therefore,  laws  of  geographical  distribution 
are  wanting,  yet  we  may  be  very  much  guided  in  our  search  for  particular 
genera  and  species  by  a  knowledge  of  their  habitats  and  of  the  conditions 
which  prove  most  favourable  to  their  existence. 

Since  the  whole  framework  of  CiKata  is  sooner  or  later  destructible  by 
diffluence,  their  occurrence  in  a  fossil  condition  is  not  to  be  looked  for. 

Affinities  of  the  Ciliated  Protozoa  with  other  Animals. — Eegarding 
as  we  do  the  organization  of  Ciliated  Protozoa  as  belonging  to  a  type  sui 
generis,  their  affinities  with  other  animals  partake  rather  of  a  general  than 
of  a  particular  character.  They  possess  an  affinity  with  Rhizopoda,  Gre- 
garinida,  and  Spongilla,  with  Opalinceay  Polypes,  and  with  many  Phytozoa, 
such  as  Euglence,  in  the  nature  of  their  contractile  substances  or  sarcode ; 
also  with  the  first  and  last-named,  in  the  presence  of  one  or  more  contractile 
vesicles.  Multiplication  by  fission  is  also  common  to  those  several  tribes,  and 
that  by  gemmation  to  Vorticellina,  Oplirydina,  and  Polypes ;  lastly,  they 
agree  with  the  Ehizopoda  and  Polycystina  in  the  process  of  dissolution  by 
diffluence.  In  the  process  of  encysting,  also,  they  are  related  with  the  Opa- 
lincea  and  Phytozoa,  with  some,  at  least,  of  the  Rhizopoda,  and,  in  general 
characters,  with  the  Gregarinida. 

Of  the  mutual  relations  between  the  Ciliata  {Opalincea,  Gregarinida)  and 
Rhizopoda,  we  shall  have  further  occasion  to  speak.  But  the  Ciliata  are 
also  allied  to  the  Rotifera  by  the  chitinous  constitution  of  their  integument, 
by  being  moved  chiefly  by  cilia,  and  more  closely  so  through  certain  fanulies, 
e.  g.  the  Vorticellina  and  Ophrydina,  which  have  a  frontal  ciliary  mechanism 
approaching  in  structure  that  of  the  rotary  apparatus.  So,  again,  in  some 
general  features,  the  sheathed  Ophrydina  (e.  g.  Vaginicola)  may  be  assimi- 
lated with  the  encased  Rotatoria,  such  as  (Ecistes  and  ConocJiihis.  Lastly, 
by  means  of  the  Ichthydina  an  additional  link  is  established  between  these 
two  classes,  and  also  betAveen  them  and  the  TurheUaria ;  for  some,  as  Schultze 
(MiiUer's  Archiv,  1853,  p.  241),  seem  disposed  to  range  the  Ichthydina  with 
the  last-named  family.    A  homology  may  be  perceived  between  the  hardened 


376  GENEBAL  HISTORY  OF  THE  INFUSOfilA. 

integument,  with  its  iincini,  styles,  and  setae,  in  such  forms  as  Coleps  and 
EwploteSj  and  the  covering  and  appendages  of  Entomostraca  and  of  some  in- 
ferior Annelida  ;  and  some  would  note  the  similarity  in  movements  between 
Coleps  and  Dajphnia. 

Through  the  Vorticellina  a  relation  is  established  with  the  Bryozoa  or 
cilio-brachiate  Polypes — one,  indeed,  which  some  naturalists  (Agassiz,  for 
instance)  affirm  to  be  so  intimate,  that  the  two  families  should  be  placed  to- 
gether in  the  same  group. 

Lastly,  there  is,  in  the  case  of  many  Ciliata,  a  very  close  apparent  affinity, 
almost  amounting  to  identity  (at  least,  so  far  as  form  is  concerned)  be- 
tween them  and  certain  embryonic  stages  of  other  animals, — for  example, 
of  Planarice  and  of  several  of  the  lowest  among  the  Vermes.  It  is  possible, 
indeed,  that  some  of  the  presumed  independent  Ciliata  are  nought  else  but 
larval  conditions  ;  but  unless  this  can  be  shown  by  direct  observation  of  their 
development  and  transformation,  they  must  be  still  retained  in  their  present 
place.  The  group  rei^resented  by  Bursaria  and  Paramecium  are,  as  Agassiz 
(A.  N.  H.  1850,  vol.  vi.  p.  156)  asserts  he  has  satisfied  himself  by  direct  in- 
vestigation, no  other  than  germs  of  fresh-water  worms,  "  some  of  which,"  he 
writes,  "  I  have  seen  hatched  from  eggs  of  Planaria  laid  under  my  eyes." 
To  this  assertion  Mr.  Girard  assents  {Proceedings  of  American  Association, 
1848,  p.  402).  However,  there  is  one  caution  to  be  borne  in  mind  in  seeking 
to  establish  the  unity  of  certain  supposed  specific  forms  and  known  embryonic 
phases  of  any  animals — viz.  not  to  confound  general  resemblance  with  specific 
identity.  For,  notwithstanding  the  former  may  be  veiy  distinct  and  close, 
this  is  not  enough  (as  the  history  of  development  of  the  higher  animals 
teaches  us)  while  there  is  aught  wanting  in  the  image,  to  render  it  an  exact 
counterpart  of  the  origiual,  identical  in  kind  with  it. 

The  above  ofi'ers  a  general  sketch  of  the  most  evident  affinities  of  the 
Ciliata.  By  the  exercise  of  the  imagination  directed  simply  to  external  form, 
these  might  be  greatly  multiphed :  this,  however,  would,  instead  of  advancing 
our  knowledge,  lead  only  to  misconceptions. 

Classification  of  the  Ciliated  Protozoa. — Among  the  many  heteroge- 
neous groups  of  beings  which  have  at  a  previous  period  been  assembled  under 
the  name  of  Infusoria,  or  other  terms  tantamount  to  it,  that  of  the  ciliated 
animalcules  has  been  more  or  less  clearly  distinguished  from  the  rest,  and 
has  received  much  attention  from  the  several  propounders  of  schemes  of  clas- 
sification. However,  as  our  knowledge  of  the  Cihata,  both  with  respect  to 
the  number  of  known  species  and  to  their  minute  organization,  on  which 
alone  any  correct  classification  can  be  based,  has  been  so  greatly  extended 
during  the  last  few  years,  it  would  be  useless  to  describe  the  various  systems 
which  were  suggested  when,  as  we  may  say,  this  branch  of  natural  history 
was  in  its  infancy. 

We  shall  therefore  omit  aU  notice  of  any  systematic  arrangement  of  the 
Ciliata  prior  to  that  proposed  by  Ehrenberg.  Now,  although  this  arrange- 
ment is  very  imperfect  and  incorrect,  and  founded,  moreover,  upon  certain 
views  of  their  organization  now  generally  rejected,  yet,  as  it  was  the  system 
adopted  in  previous  editions  of  this  work,  and  mil  be  generally  followed  in 
the  present  one ;  and  as,  moreover,  no  other  classification  can  lay  claim  to 
such  completeness  and  accuracy  as  to  command  its  adoption  instead,  it 
behoves  us  to  detail  its  principal  features.  Besides  this  distribution  of  Ciliata, 
suggested  by  the  great  micrographer  of  Berhn,  there  are  three  others  it 
win  be  necessary  to  describe  in  this  place,  severally  proposed  by  Dujardin, 
Siebold,  and  Perty.  Of  these,  however,  it  will  only  be  necessary  to  present 
the  outline  as  given  by  their  respective  authors,  since  the  examination  of  the 


OF  THE  PROTOZOA. CILIATA.  377 

characters,  limits,  and  mutual  relations  of  the  families  described  will  form 
the  subject  of  the  Systematic  portion  of  this  work. 

The  Ciliata,  in  our  meaning,  are  very  nearly  the  same  beings  that  Ehren- 
berg  called  Etiterodela,  or  Polygastriea  furnished  with  an  intestine  connecting 
together  their  stomach- sacs.  A  division  of  the  Enterodela  was  made,  accord- 
ing to  the  mutual  relation  in  position  between  the  two  orifices  of  the  body — 
the  mouth,  and  anus  or  discharging  vent — into,  1st,  Anopisthia,  in  which  the 
intestine  is  so  curved  on  itself  that  its  two  ends  unite  together  in  a  common 
aperture ;  2,  Enantiotreta,  having  an  oral  opening  at  one  extremity,  and  the 
anal  at  the  other,  i.  e.  opposite  to  each  other ;  3,  Allotreta,  mth  the  two 
orifices  placed  obliquely  with  reference  to  one  another ;  and  4,  Catotreta, 
with  both  situated  on  one  surface — the  abdominal.  The  subjoined  tabular 
view  will  display  these  divisions,  and  also  their  subdivision  into  families. 

We  have  departed  from  this  arrangement  of  Ehrenberg  chiefly  by  omitting 
a  few  genera  and  species,  viz.  Actinoj^hrys,  TrichodiscuSj  and  Podojphrya 
among  the  Enchelia,  and  some  species  of  Bursaria  from  the  TracJielina,  and 
also  by  adding  several  new  genera  and  families.  Concerning  the  necessity  of 
detaching  the  Actinophrys  and  its  two  congeners  from  the  Enchelia,  no  doubt 
can  be  entertained  when  their  structure  comes  to  be  considered  ;  we  have 
thrown  them  together  into  one  family  under  the  name  of  Actinophryina 
(p.  243),  and  have  brought  them  and  the  peculiar  beings  known  as  Acinetina 
(p.  258)  together  as  two  subdivisions  of  Rhizopoda.  The  peculiar  parasitic 
BursaricB  without  mouth  constitute,  with  some  similar  ciliated  mouthless 
beings,  a  subdivision  of  the  CHiata,  standing  in  near  relation  with  Gregari- 
nida,  and,  in  some  measure,  intermediate  between  the  Ciliata  and  Rhizopoda. 
Lastly,  we  have  removed  the  Ichthydina  from  the  Rotatoria,  and  treated  them 
as  a  subclass  of  Ciliata.  The  additional  families  and  genera  we  shall  not  here 
specify,  but  must  direct  the  reader  forinformation  to  the  systematic  descriptions. 

The  following  tabular  view  represents  Ehrenberg's  classification. 


]■ 


One  receiving 

and  discharging  [  illoricated    VorticeUina. 

orifice  only  for    y 

nutrition.        [  loricated  Ophrydina. 

Anopisthia. 


Two  orifices : 

one  at 

each  extremity. 

Enantiotreta. 


I  illoricated    EncheHa. 

I  loricated Colepina. 


I^mouth    furnished    with    pro- 1  ^ra^helina. 

Orifices  situated  fiUoricated    i      boscis,  tail  absent    :-/_, 

obKauelv        -i  mouth  anterior,  tail  present Ophryocercinfi 

( loricated  Aspidisciaa. 


Allotreta. 


Orifices 

abdominal. 

Catotreta. 


f  r  locomotive  organs,  cilia Kolpodea. 

illoricated    \ 

[ various Ox  jtrichina. 

^  loricated Euplota. 


Dujardin's  distribution  next  claims  attention.  Having,  as  we  have  seen, 
entirely  rejected  Ehrenberg's  polygastric  hypothesis,  and  at  the  same  time 
failed  to  recognize  many  important  points  of  internal  organization  now 
well  established,  he   had,   to  construct   his    system,    recourse   to   external 


378 


GENERAL  HISTORY  OF  THE  INFUSORIA. 


characters  only — to  the  presence  or  absence  of  locomotive  organs,  to  the 
characters  of  those  organs,  to  the  nature  of  the  external  surface,  whether 
protected  by  an  integument  or  not,  or  defended  by  a  lorica,  to  the  general 
conditions  of  attachment  of  fixed  forms  to  other  objects,  and  to  the  cha- 
racter of  their  movements  when  free.  Moreover,  his  Ciliated  Infusoria  com- 
prised not  only  our  group  of  Ciliated  Protozoa,  but  also  the  Phytozoa, — the 
Vibrionia  only  excepted ;  for  he  made  no  distinction  between  organisms  moved 
by  a  single  or  few  filaments,  and  those  moved  by  vibratile  ciha  generally  dis- 
tributed, or  associated  together  in  the  construction  of  special  locomotive  organs. 

In  his  tabular  view,  the  beings  we  have  brought  together  under  the  appel- 
lation of  Cihata  are  all  comprehended  in  the  foui'th  and  fifth  orders  of  Infu- 
soria, with  the  exception  of  CoUps  and  the  Iclithydina,  which,  in  his  opuiion, 
belong  to  a  type  of  structm^e  differing  from  all  others  reckoned  by  him  as 
Infusoria,  in  being  symmetrical. 

The  accompanying  outline  of  this  system  of  Dujardin  ^vtU  sufficiently  illus- 
trate it  at  present,  without  further  remarks  on  the  value  either  of  the  prin- 
ciples he  has  adopted,  or  of  the  families  and  genera  he  has  instituted. 

DUJAEDIJf'S  CLASSIFICATION  OF  CILIATA. 

Order  IV. — Cihated  animalcules  without  a  contractile  integument.  All  swimmers. 

A.  Naked. 

Fam.  11.  Enchelyens,  without  mouth;  ciUa  disposed  without  order. 

12.  Trichodiens,  with  the  mouth  either  visible  or  indicated  by  a  fringe  of  cilia,  with- 

out cirrhi. 

13.  Keroniens,  with  a  mouth  and  a  fringe  of  ciha,  together  with  some  cirrhi  or 

strong  cilia  in  the  form  of  styles  or  uncini. 

B.  LORICATED. 

Fam.  14.  Ploesconiens.  Lorica  or  sliield  diffluent  or  decomposable  like  the  rest  of  the  body. 
15.  Ervihens.     Lorica  genuine  and  persistent.     A  short  pedicle. 

Order  V. — Ciliated  animalcules  provided  with  a  lax,  reticulated,  and  contractile  integu- 
ment ;  or  having  theu'  ciha  so  arranged  in  regular  linear  series  as  to 
denote  the  presence  of  an  integimient. 
A.  Always  free. 

Fam.  16.  Leucophry ens,  without  a  mouth. 

17.  Parameciens,  with  a  mouth  but  no  prominent  row  of  cilia. 

18.  Bursariens,  with  a  mouth  and  a  prominent  row  of  cilia. 

B. — Either  voluntarily  attached  or  fixed  by  the  medium  of  organs. 
Fam.  19.  Urceolariens,  voluntarily  attached. 

20.  VorticeUiens,  attached  at  least  temporarily  either  by  their  organs  or  by  some 
part  of  their  body. 

Symmetrical  Infusoria. — Of  several  types  without  mutual  relations. 
Planariola.     Coleps.     Chsetonotus.     Ichthydium. 

With  the  exception  of  the  family  Leucophry  ens,  which  is  nearly  equivalent 
to  our  subgroup  Opalincea,  and  of  the  genera  Planariola,  (Jlu:^tonotus,  and 
Ichthydium  (the  two  last  constitute  our  family  Ichthydina),  all  the  other 
families  and  genera  are  members  of  our  class  of  Ciliata,  and  are  described  in 
the  Systematic  portion  of  this  work. 

Prof.  Siebold  (Amitomie  der  WirbeUosen  Thiere)  agreed  with  Dujardin  in 
rejecting  the  Polygastrica  of  Ehrenberg  as  a  class,  and  at  the  same  time  em- 
ployed the  term  Infusoria,  applied  after  Ehrenberg's  example  to  a  multitude 
of  various  organisms  both  animal  and  vegetable,  to  designate  a  comparatively 
limited  group.  To  this  restricted  use  of  the  teim  we  have  abeady  objected 
(p.  199)  ;  we  will  now,  therefore,  proceed  with  the  classification  in  question. 
Siebold's  Infusoria  included  all  those  microscopic  organisms,  exclusive  of  the 
Rhizopoda,  of  supposed  animal  nature,  whether  possessing  a  mouth  or  not. 
Of  these  he  made  two  classes :  one  named  Astoma,  the  other  Stomatoda,  the 
latter  equivalent  to  our  Ciliata.     The  following  tabular  outUne  is  presented 


OF  THE  PROTOZOA. CILIATA.  379 

by  Siebold,  without  any  comments  on  the  characters  and  distinctions  of  the 
several  families,  which,  however,  agree  in  general  with  those  instituted  by 
Ehi'enberg,  the  most  striking  departure  being  the  exclusion  of  Ojphryocercina 
and  Aspidiscina. 

SIEBOLD'S    CLASSIFICATION    OF    CILIATA. 
Class  I. — INFt^SOKIA,  Aiiimals  moving  by  cilia. 
Order  1. — Astoma,  Infusoria  without  a  mouth. 
Fam.  1.  AsTASi^A. — Gen.  Amblyophis,  Euglena,  Chlorogonium. 
Fam.  2.  Peridinlea. —  Gen.  Peridinium,  Grlenodinium. 
Fam.  3.  Opaline  A. — Gen.  Opalina. 

Order  2. — Stomatoda,  Infusoria  with  a  mouth. 
Fam.  1.  VoRTiCELLiNA. — Gen.  Stentor,  Triehodina,  VorticeUa,  Epistylis,  Carchesium. 
Fam.  2.  Ophrydina. — Gen.  Vaginicola,  Cothm'nia. 
Fam.  3.  Enchelia. —  Gen.  Actinophrys,  Leucophrys,  Prorodon. 
Fam.  4.  Trachelina. — Ge7i.  Glaucoma,    Spirostomum,    Trachelius,   Loxodes,    Chilodou, 

Phialina,  Bursaria,  Nassula. 
Fam.  5.  Kolpodea. — Gen.  Kolpoda,  Paramecium,  Amphileptus. 
Fam.  6.  Oxytrichina. — Gen.  Oxytricha,  Stylonychia. 
Fam.  7.  Euplota. — Gen.  Euplotes,  Himautophorus,  Chlamidodon. 

Perty  is  the  latest  writer,  as  far  as  we  can  discover,  who  has  attempted  a 
classification  of  Infusoria,  among  w^hich  he  distinguishes,  as  we  do,  a  class 
under  the  name  of  Ciliata,  having  also  in  almost  all  respects  similar  limits, 
except  in  the  retention  of  the  Actinophryina  as  one  of  the  two  sections  he 
makes,  viz.,  1,  animalcules  with  vibratile  cilia ;  and  2,  with  non -vibrating 
but  shghtly  contractile  cilia,  or  filaments.  Leaving  this  second  section  out 
of  view,  the  other  is  divided  into  three  subsections,  with  the  titles  Spastica, 
Monima,  and  Metaholica,  according  to  the  varying  character  of  their  move- 
ments, which  in  the  first  are  sudden  and  jerking,  in  the  second,  unvai-jing 
and  constant,  and  in  the  thii'd,  associated  with  striking  changes  in  the  figure 
of  the  body.  Under  these  three  subsections  he  distributes  all  the  Ciliata  into 
families,  to  many  of  which,  in  departing  from  Ehrenberg's  groupings,  he  has 
given  new  names.  He  moreover  describes  many  new  genera  and  species. 
Besides  the  Actinopliryina,  we  exclude  also  the  family  Cobaliiia,  which  is 
equal  to  our  family  Opalinfea,  and  to  Dujardin's  Leucop>hryens. 

We  shall  attempt  to  represent  this  system  of  classification  by  a  tabular 
outline : — 

PERTY'S  CLASSIFICATION  OF  CILIATA. 

A.  Spastica. — Animalcules  capable  of  contracting  their  bodies  and  their  stems,  when  suck 

exist,  in  a  sudden  spasmodic  manner,  so  that  their  Tnore  or  less  elongated 
figure  is  rendered  oval  or  globular,  and  the  stem  coiled  spirally.  They 
are  the  only  Ciliata  which  live  associated,  and  are  related  to  Bryozoa, 
and  many  to  Rotatoria. 

Fatu.  1.  Vaginifera. — Enclosed  in  a  sheath,  into  which  they  can  withdraw  themselves. 
Mouth  with  a  ciliary  wreath. 

Fam.  2.  Vorticellina. — ^Without  a  sheath  ;  living  isolately,  or  in  arborescent  polyparies  ; 
with  a  contractile  body  and  evident  mouth,  but  no  intestine.  Deve- 
loped by  fission,  by  germs,  and  gemmation,  and  by  means  of  transi- 
tional phases. 

Fam.  3.  Ophrydina. — Numerous  animalcules  associated  together  in  a  solid  gelatinous  mass, 
but  without  contractile  fibres. 

Fam.  4.  Urceolarina. — The  Urceolariens  of  Dujardin,  Ophrydium  being  excluded,  and 
Spirostomum  added. 

B.  Monima. — Animalcules  which,  although  very  contractile,  neither  undergo  change  of  form 

nor  exhibit  jerking  movements. 

A.  General  covering  soft. — 1.  Free  forms,  with  a  tnouth  ;  nutriment  received  solid. 
Fam.  o.  BuRSARiNA, 
Fam.  6.  Paramecina.— Body  covered  by  longitudinal  rows  of  cilia.     Mouth  lateral,  often 

situated  in  a  fmn*ow, 
Fam.  7.  Holophryina. — Mouth  anterior ;  anus  posterior.     Cilia  in  longitudinal  rows. 


380  GENEEAL  HISTOEY  OF  THE  II4FTJS0EIA. 

Fam.  8.  Aphthonia. — Surface  ciliated,  and  furnished  besides  with  filaments. 

Fam.  9.  Decteria. — Mouth  provided  with  a  circlet  of  bristles  ;  in  three  genera  lateral,  in 

two  anterior  in  position. 
Fam.  10.  CiNETOCHiLiNA. — Mouth  on  the  upper  surface,  furnished  with  a  vibrating  flap. 

Cilia  in  longitudinal  lines. 
Fam.  11.  Apionidina  (in  part  the  Enchelia,  Ehr.,  and  the  Parameciens,  Bicj.). — Bodies 

small,  soft,  thicker  at  one  end  than  the  other ;  cilia  in  longitudinal 

rows.     Mouth,  where  perceptible,  at  the  anterior  extremity. 
Fam.  12.  Tapinia. — Cilia  scattered,  or  collected  in  particiilar  spots,  but  never  in  rows. 

Body  usually  very  small.     Mouth  only  proved  to  exist  by  means  of 

artificial  feeding. 
Fam.  13.  Trachblina. — Body  elongated  into  a  neck-like  anterior  process,  or  a  laterally 

curved  trunk. 
Fam.  14.  Oxytrichina. — Equal  the  Keroniens  of  Dujardin. 

2.  Parasitical  forms,  with  or  without  a  mouth,  Tnostly  receiving  only  the  juices  of 
other  animals. 

Fam.  15.  Cobalina. — Body  mostly  flattened,  oval,  elliptic  or  reniform,  covered  by  numer- 
ous rows  of  fine  cilia,  and  oftentimes  with  jointed  cilia  on  the  under 
surface.  A  raised  margin  or  hollow  fold  occupied  by  cilia  often 
indicates  the  mouth,  of  which,  however,  in  several  cases,  no  trace  is 
evident.  The  animalcules  commonly  live  internally,  upon  the  juices 
of  other  beings,  and  occasionally  on  their  outer  siu'face,  in  which  case 
the  food  they  take  is  soHd.  They  present  among  themselves  numerous 
peculiarities  and  points  of  agreement,  and  at  the  same  time  many 
anomalies,  and  are  lower  in  the  scale  than  free  living  forms  similar  to 
them,  e.g.  Oxytrichina;  their  movements  are  rather  automatic.  The 
genera  included  are,  Alastor  (Kerona,  Ehr.),  Plagiotoma,  Leucophrys, 
and  Opalina. 
B.  General  covering  firm  by  induration  of  the  integument,  or  by  excretion  of  hard 
granules. 

Fam.  16.  Euplotina. — Equal  the  Ploesconiens  of  Dujardin. 

Fam.  17.  Colepina. — Represented  by  the  genus  Coleps  (Ehr.). 

C.  Metabolica. —  Very  contractile  ;  undergoing  protean  alterations  of  their  figure  through 
a  contraction  and  extension  of  the  body.  Cilia  scarcely  observable  on 
the  body  at  large,  but  collected  on  the  neck-like  process. 

Fam.  18.  Ophryocercina  (Ehr.),  including  also  Trachelocerca  and  Phialina. 

FAMILY  I.— ICHTHYDINA. 
(Plates  XXY.  357,  358.  Plate  XXXI.  28,  29,  31.) 
This  family,  which  in  our  arrangement  forms  a  subgroup  of  Ciliata,  con- 
stituted in  Ehrenberg's  system  a  section  of  Eotatoria, — an  association  which 
cannot  be  maintained  now  that  theii'  more  intimate  and  essential  organiza- 
tion is  known.  Indeed,  these  beings  seem  to  have  received  but  little  atten- 
tion from  that  great  naturalist,  who  had  only  an  imperfect  accoimt  of  them 
to  offer.  They  were  described  as  Rotatoria  with  a  single  continuous  rotary 
organ,  not  cut  or  lobed  at  the  margin,  and  without  lorica  or  shell.  Four 
genera  were  enumerated — viz.  Ptggura,  Iclithydium,  Chcetonotus,  and  Gleno- 
pliora.  Their  relative  peculiarities  were  thus  stated : — Ptggura  and  Gleno- 
pliora  had  a  simple  rotary  locomotive  organ;  Ichthgdium  and  Chcetonotus, 
only  a  long  ciliary  band  upon  the  ventral  surface.  Again,  the  two  foimer 
had  a  simple  foot-like  process,  and  evident  oesophageal  teeth ;  the  two  latter 
a  forked  tail  and  no  visible  teeth.  Dujardin,  who  has  given  a  very  good 
account  of  (Jlicetonotus,  rejected  that  genus,  together  with  Ichthgdium,  from 
among  the  Rotatoria,  and  placed  the  two  in  a  sort  of  subfamily  of  Ciliated 
Protozoa,  under  the  name  of  '  Symmetrical  Infusoria.'  Of  the  other  two 
genera,  Glenophora  and  Ptggura,  he  ignored  altogether  the  former,  and 
transposed  the  latter  to  his  family  of  '  Melicertiens.^  Since  the  date  of  his 
systematic  treatise  (Hist,  des  Infus.  1841),  he  has  sketched  the  histoiy  of  a 
genus  under  the  name  of  EUimoderia,  which  is  evidently  allied  to  Chcetonotus 
(A.  S.  N.  XV.  p.  158). 


OF  THE  PKOTOZOA. TCHTHTDINA. 


381 


The  latest  researches,  we  have  seen,  on  the  Ichihydina  are  contained  in  a 
paper  by  Dr.  Max.  Schiiltze  {Mull.  Archiv,  1853,  p.  241),  on  ChcBtonotus  and 
Ichthydium,  and  on  a  new  allied  genus,  Turbanella.  In  this  communication 
Schultze  clearly  shows  that  Glicetonotiis  and  IcJitliydmm  are  not  Eotatoria, 
whilst  he  admits  Ptygura  and  Glenophora  to  be  so.  The  leading  and  suffi- 
cient reasons  for  sej)arating  Ichthydium  and  Chcetonotus  from  Rotatoria  are, 
that  they  want  the  peculiar  ciliary  apparatus  of  that  class  have  no  retractile 
rotary  disk,  no  jointed  tail-hke  process,  no  water- vascular  system  with 
vibratne  tags,  and  no  perceptible  muscular  and  nervous  system.  The  best 
account  of  the  organization  we  have  of  any  of  the  Ichthydina  is  furnished  by 
Schultze's  contribution  above  quoted,  wherein  he  details  that  of  TurhmieUa. 
Of  this  we  will  present  an  abstract,  but,  before  so  doing,  will  preface  a  few 
notes  from  Dujardin  on  Chcetonotus.  This  genus  has  a  symmetrical  elongated- 
oblong  body  slightly  contracted  at  its  anterior  thii'd,  and  having  its  posterior 
half  expanded  ;  covered  on  its  upper  or  posterior  surface  by  cilia  or  by  cihated 
scales ;  terminated  anteriorly  by  a  rounded  edge,  near  to  which  is  a  distinct 
circular  oral  aperture  ;  and  posteriorly  ending  by  a  bifurcate  process.  Some 
long  vibratile  cilia  are  visible  on  the  anterior  half  of  the  ventral  surface ;  and 
Dujardin  thought  he  discovered  four  or  five  minute  papillae  around  the  mouth. 
This  aperture  he  represents  to  lead  into  a  long  narrow  oesophagus,  which 
abruptly  ends  in  a  wide  intestine,  that  continues  a  straight  course  to  the 
posterior  extremity,  where  an  anal  opening  is  probably  placed.  The  Turba- 
nella hyalina,  of  Schultze,  has  an  elongated,  rather  compressed,  colourless 
body,  from  -gijth  to  ^th  of  an  inch  long,  and  j-^-yth  to  y-g-jj^^  broad.  The  head  is 
separated  from  the  body  by  a  constriction  (XXXI.  28).  Along  the  body,  at 
apparently  regular  distances,  numerous  bristle-like  processes  stand  out  at  right 
angles  on  each  side.  The  posterior  extremity  is  slightly  contracted,  and 
divided  into  two  comb-like  flattened  processes  or  lameUae,  having  an  inter- 
vening fossa,  into  which  the  anal  aperture  opens.  A  dorsal  and  ventral 
surface  are  distinguishable, — the  latter  ciliated  throughout,  the  former  bare. 
The  head  is  entirely  covered  on  its  upper  surface  by  fine  cilia,  besides  which, 
it  has  a  circlet  of  larger  ones  around  its  middle.  The  cihated  condition  of 
the  under  surface  is  displayed  by  a  side  or  a  transverse  view  of  the  animal. 
The  bristle-like  processes  on  each  side  are  growths  from  the  integument,  and 
neither  articulated  nor  separable  (XXXI.  28,  30).  The  row  is  double  on 
either  side  ;  the  under  setae  from  20  to  25  in  number ;  the  upper,  only  from 
6  to  8  on  a  side.  The  latter  are  rather  appendages  of  the  dorsal  surface, 
and  are,  moreover,  not  at  right  angles  like  the  others,  but  bent  backward. 
Each  cutaneous  process  is  terminated  by  a  motionless  cilium,  equal  to  or  ex- 
ceeding it  in  length.  The  cuticle  and  its  processes  are  soluble  in  a  warm 
solution  of  potash,  and  are  not  chitinous. 

The  ahmentar}'  canal  passes  straight  through  the  middle  of  the  body  (XXX. 
28,  29).  The  mouth,  situated  at  the  anterior  extremity,  is  cii^ular,  and  sur- 
rounded by  a  finely  plicate  or  dentate  margin ;  it  opens  into  a  muscular 
oesophagus,  which  very  much  resembles  that  of  Anguillida,  and  terminates 
below  in  the  straight  intestine.  The  oesophagus  extends  for  the  first  fourth 
of  the  length  of  the  body ;  and  its  muscular  coat  is  so  developed,  that  its  canal 
looks  like  a  mere  central  Hue.  Its  muscles  are  annular.  The  tubular  intes- 
tine has,  on  the  contrary,  thin  walls,  in  which  numerous  molecules  and  fat- 
corpuscles  are  distinguishable,  except,  indeed,  at  its  posterior  conical  termina- 
tion. The  intestine  lies  in  a  soft,  finely-granular  parenchyma.  Xo  water- 
vascular  apparatus  with  vibratile  tags  exists.  At  the  posterior  thii^d  of  the 
body,  on  the  dorsal  surface  of  the  intestine,  a  large  ovary  is  placed,  and  in 
front  of  it  a  veiy  much  smaller  testis.     Both  glands  present  a  mulberry- 


382  GENEEAL  HISTORY  OF  THE  LNTUSORIA. 

like  aggregation  of  rounded  cells.  The  posterior  portion  of  the  ovary  exhibits 
ova,  having  a  germinal  vesicle  and  spot  surrounded  by  a  fine  granular  yelk- 
mass  ;  and  one  or  two  ova  are  frequently  seen  separated,  having  a  delicate 
colourless  shell  developed  around  them.  The  diameter  of  the  largest  ova 
equals ^^Q-th.  The  mature  eggs  lie  close  to  the  testes.  Besides  this  distinct 
male  organ,  two  groups  of  sjpermatozoid-ceMs  seem  present,  lying  apparently 
free  in  the  loose  parenchyma,  and  apparently  without  any  investing  membrane 
or  envelope.  As  to  their  affinity,  Schultze  makes  no  doubt  that  they  are 
Vermes,  and  belong  to  the  group  of  Turbellaria,  considered  as  a  division  of 
the  Cestoidea.  Among  Turbellaria  they  are  best  placed  with  the  Arhynchia, 
including  Mkrostomum  and  DlnopliUus.  They  resemble  Nematoidea  and 
Anquilhdce  in  the  form  of  the  intestinal  canal,  but  are  unlike  these  in  their 
figure,  their  ciliated  integument,  and  their  hermaphrodite  structiu-e. 

The  IcJithi/dina  are  inhabitants  of  fresh  water,  l\ving  among  aquatic  plants. 
They  have  a  sluggish,  creeping  gliding  movement,  resembling  that  of  most 
Turbellaria. 

FAMILY  II.— NOCTILUCIDA. 

(Plate  XXXI.  32-39). 

This  small  but  remarkable  subsection  is  represented  by  only  one  animal, 
the  Noctduca  mdiayns,  which  has  attracted  much  attention  as  one  of  the 
sources  of  the  phosphorescence  of  the  sea.  By  several  recent  authors  it 
has  been  treated  as  a  near  aUy  of  the  Cihata,  although  it  must  be  confessed 
to  have  few  outward  indications  of  such  a  relationship,  and,  in  oui'  estima- 
tion, is  a  representative  of  quite  a  different  and  independent  group  of 
animals.  At  first  sight,  a  Noctduca  appears  a  round  gelatinous  corpuscle 
having  a  depression  or  groove  at  one  part,  surmounted  by  a  filamentary  pro- 
cess or  tentacle.  Compared  with  the  Ciliated  Protozoa,  it  is  of  gigantic  pro- 
portions, attaining  -gL-th  of  an  inch  in  diameter.  On  closer  examination  it  is 
found  to  have  an  integument  of  two  layers :  the  outer  smooth  and  reticular, 
structureless,  and  of  considerable  density ;  the  inner  a  delicate,  granular, 
gelatinous  membrane,  which  Dr.  Webb  {J.  M.  S.  1855,  p.  103)  describes  to  be 
in  union  at  all  points  with  the  whole  system  of  reticulations  spreading  from 
the  central  organs, — a  fact  rendered  e\ident  by  the  action  of  indigo  and  the 
primary  changes  consequent  on  death.  ''  The  internal  fibrous  reticulations 
gradually  contracted,  drawing  the  '  vacuoles '  together,  and  with  them  the 
inner  membrane.  This  was  detached  without  rupture,  but  after  a  time  fell 
into  folds,  which  so  included  the  other  structures  as  to  have  the  look  of  a 
wrinkled  tube  with  a  series  of  pouches  ending  in  a  larger  membranous  sac. 
The  external  layer  distended  by  degrees  till  it  suddenly  burst.  I  should 
mention  that  a  new  supi^ly  of  water  had  been  given  before  most  of  these 
changes  happened.  I  have  also  been  successful  in  separating  the  two  layers 
mechanically,  by  means  of  pressure,  slowly  and  steadily  appKed  to  the  animal 
under  the  screw  compressor."  The  external  membrane  is  extended  at  one 
point  into  a  tapering  process,  which  acts  as  a  locomotive  organ.  It  springs 
from  the  edge  of  the  infundibulum,  which  is  extended  backwards  into  a  pha- 
rynx or  gullet.  This  process  or  tentacle  appears  transversely  striped,  and 
breaks  short ;  of  the  nature  of  those  stripes  we  know  nothing.  Dr.  Webb 
believes  this  process  to  be  tubular,  with  an  orifice  on  the  inner  side  at 
its  base.  "  At  any  rate,"  he  wiites,  "  1  have  seen  the  colour,  when  iodine 
has  been  used,  proceed  towards  the  distal  extremity ;  and  under  the  influence 
of  indigo  poisoning,  the  granular  matter  of  which  the  striation  consists  has 
been  disarranged,  scattered  up  and  down  the  interior  of  the  organ,  and  in  the 
end  has  aggregated  together  in  small  globules,  without  much  impairing  the 


OF  THE  PROTOZOA. NOCTlLrCIDA.  383 

power  of  motion."  These  appearances  do  not  at  all  convince  us  of  the  tubular 
character  of  the  tentacle  ;  for  they  are  attributable  to  the  difference  of  action 
of  the  chemical  reagents  upon  the  contained  matter  and  upon  its  investment. 
Dr.  "Webb  adds — "  I  have  never  perceived  any  tendency  to  restoration  of  the 
lost  part,  nor  any  independent  movement  in  the  detached  fragment.  The 
stump  continues  active,  and  readily  comes  off  at  the  base.  The  point  is  a 
Uttle  flattened.  When  the  animal  is  killed  in  such  a  manner  that  this  organ 
has  free  play,  it  always  shows  a  disposition  to  coil  up  spirally." 

Prof.  Huxley's  comparison  of  the  Noctiluca,  in  figure,  to  a  peach  is  very 
good,  and  conveys  a  clear  idea  of  the  relative  position  of  the  external  groove 
and  its  appendages  {J.  M.  S.  1854,  p.  50).  "  One  surface,"  he  writes,  "  is  a 
httle  excavated  ;  and  a  groove  or  depression  runs  from  one  side  of  the  excava- 
tion, halfway  to  the  other  pole.  Where  the  stalk  of  the  peach  might  be,  a 
fihform  tentacle,  equal  in  length  to  about  the  diameter  of  the  body,  depends 
from  it,  and  exhibits  slow  wa\y  motions  when  the  creature  is  in  full  activity. 
I  have  even  seen  a  Noctiluca  appear  to  push  repeatedly  against  obstacles  with 
this  tentacle."  Behind  the  tentacle  is  a  rounded  or  oval  mouth,  having  a 
harder  margin  extending  from  the  base  of  the  tentacle,  along  its  right  side,  in 
the  form  of  an  elevated  ridge.  This  ridge  has  a  horny  appearance  (although 
Dr.  Webb  declares  it  to  be  of  fibrous  consistence),  and  is  usually  described  as 
sigmoid  in  outhne.  About  its  middle  is  a  triple  (tricuspid)  tooth-like  eleva- 
tion, composed  of  a  middle,  bifid,  large  portion,  and  a  smaller  one  on  each  side. 
Dr.  Webb  says  that  when  this  tooth  is  "  seen  in  profile,  it  has  the  appear- 
ance of  a  conical  papilla,  or,  with  a  slight  change  in  the  point  of  view,  of  a 
hooked  process  terminating  in  a  sharp  nib.  It  readily  fields  to  pressure ; 
and  I  have  seen  it  become  shrivelled  up  from  the  use  of  astringents,  before 
motion  ceased  in  the  cilium  and  tentacle ....  The  ridge  may  be  sometimes 
observed  in  regular  contractile  action.  Corresponding  with  these  contrac- 
tions, I  have  witnessed  a  to-and-fro  motion  of  the  tooth,  as  though  working 
on  an  axis  in  a  dii^ection  towards  the  base  of  the  tentacle.  A  good  illustra- 
tion of  this  performance  is  given  by  bending  the  fore  and  middle  fingers,  and 
flexing  them  on  the  palm  of  the  hand."  On  the  other  hand.  Prof.  Huxley 
states  that  he  never  observed  any  movement  in  this  tooth-like  body. 

The  oral  aperture  opens  into  a  funnel-Hke  ca\dty  or  pharjmx,  from  the 
bottom  of  which  a  ciliary  process  extends,  having  a  rapid  undulatory  move- 
ment, and  retractile.  Mr.  Huxley  only  now  and  then  detected  this  cilium, 
and  states  that  it  is  difficult  of  observation ;  but  Dr.  Webb  says — •'  The 
cilium  may  be  found  in  every  instance  in  which  it  is  looked  for  with  a 
quarter-inch  glass,  or  even  with  the  half-inch,  provided  the  creatui'e  is  left 
at  perfect  hberty,  and  is  made  to  move  if  not  in  the  right  position.  It  often 
remains  at  rest  for  some  time,  and  then  from  above  looks  like  a  small  bright 
spot  at  the  base  of  the  '  tooth  ; '  or  it  may  occasionally  be  seen  extended  over 
the  S-shaped  ridge,  or  even  the  base  of  the  tentacle.  I  have  many  times 
detected  it  in  motion  from  behind,  thi^ough  the  intervening  substance  of  the 
body,  and  have  noticed  it  vibrating  vigorously  long  after  rupture  of  the 
integument  and  partial  discharge  of  the  contents.  A  Chara-trough,  or  shallow 
concave  ceU,  is  most  convenient  for  observations  on  this  part,  as  the  animal 
swims  close  to  the  under  surface  of  the  thin  glass,  and  may  be  made  to  turn 
in  any  direction." 

A  minute  oval  aperture  is  represented  both  by  Huxley  and  Webb  as  open- 
ing into  the  funnel-shaped  oral  cavity.  This  last  expands  into  an  ahmentary 
space  "  of  very  various  form  and  dimensions,  capable  of  great  dilatation,  and 
presenting  no  distinct  walls,  but  rather  excavated  in  the  central  substance  of 
the  body,  which  is  connected  with  the  parietes  by  numerous  granular  radi- 


384  GEITEEAL  HISTORY  OF  THE  INFFSORIA. 

ating  filaments  "  {Huxley^ s  Lectures,  Medical  Times,  1856,  vol.  xxxiii.  p.  511). 
These  granular  filaments  radiate,  from  a  central  portion  which  seems  to 
serve  as  a  bond  of  union  and  a  basis  of  support  for  all  the  organs  about  the 
oral  cavity,  to  the  integument  in  every  direction ;  and  probably  the  apparent 
reticulation  of  the  external  membrane  is  due  to  the  crossing  of  the  very 
fine  terminations  of  those  filaments  as  they  proceed  to  attach  themselves  to 
it.  Lying  amid  the  meshes  of  this  fibrous  network,  chiefly  towards  the 
centre  of  the  Noctiluca,  are  more  or  fewer  vacuolar  bodies.  "  The  whole 
internal  network  of  fibrous  tissue,"  writes  Dr.  Webb  (op.  cit.  p.  104),  "  with 
the  manner  in  which  it  invests  the  so-caUed  vacuoles,  is  most  beautifully 
demonstrated  by  the  effect  of  iodine.  The  creature  dies  suddenly,  without 
collapsing.  The  progress  of  the  fluid  can  be  traced  along  the  fibres  into  the 
minutest  meshes ;  and  there  remains  for  a  long  time  a  transparent  baU, 
traversed  in  every  direction  by  the  brown  fibres,  headed  with  the  vacuoles 
and  granules,  and  having  every  reticulation  on  the  surface  sharply  defined." 

The  ''  vacuoles  "  referred  to  are  not  homologous  with  those  of  Protozoa, 
and,  to  avoid  confusion,  another  name  should  be  found  for  them.  They  are 
actual  sacs  or  cells,  with  a  definite  membranous  wall,  and  thus  appear  to 
resemble  in  structure  the  contractile  sacs  of  Protozoa.  Dr.  Webb  asserts 
them  to  be  alimentary  sacs  ;  and  we  gather  from  him  the  following  account 
of  them  {op.  cit.  p.  105)  : — "  When  empty,  they  are  usually  contracted  and 
grouped  near  the  membranous  tube  which  leads  from  the  oral  aperture — 
a  few  only  being  scattered  among  the  internal  reticulations.  Their  situa- 
tion is  constantly  changing,  sometimes  with  a  steady  advance,  at  others  by 
jerks,  while  the  fibrous  meshes  with  which  they  are  connected  undergo  a 
relative  alteration  in  shape.  Gentle  pressure  will  occasionally  expel  them 
through  the  oral  or  anal  aperture ;  but  I  have  seen  them  spontaneously 
ejected  mthout  ruptm^e,  and  float  away  from  the  body.  In  one  instance 
where  this  occurred,  and  where  the  contents  consisted  of  granular  matter, 
fragments  of  Diatomacece,  and  particles  of  sand,  the  sac  remained  entire  for 
some  time.  When  it  burst,  the  membrane  doubled  up,  the  contents  escaped, 
and  the  bits  of  silica  were  characteristically  shown  with  the  polariscope.  I 
have  never  known  these  gastric  pouches,  or  alimentary  substances  to  be 
voided  by  any  other  outlet  than  those  connected  with  the  central  depression." 

At  the  bottom  of  the  infimdibulum  is  a  large-sized  oval,  or  ovoid,  brownish 
body,  of  granular  consistence,  and  strongly  refracting  light,  which  is  the 
nucleus.  It  lies  in  front  of  and  above  the  gastric  cavity,  and.  Prof.  Huxley 
states  (op.  cit.  p.  54),  assumes  the  appearance  of  a  hollow  vesicle  when  acted 
upon  by  acetic  acid.  Dr.  Webb  writes  {op.  cit.  p.  106) — "  The  nucleus  may 
be  demonstrated  as  a  nucleated  vesicle,  sometimes  solitary,  more  frequently 
with  several  similar  but  smaller  nucleated  vesicles  grouped  around  it.  By 
careful  manipulation  it  may  be  removed  from  the  other  structures ;  and  as  it 
floats  about,  its  true  form  is  displayed.  Seen  in  one  position,  you  have  a  view 
of  a  round  vesicle  with  a  smaller  vesicle  attached  to  it  by  a  sort  of  hour-glass 
contraction ;  in  another,  of  a  round  vesicle  with  a  central  spot,  a  nucleated 
cell.  I  have  found  the  nucleus  enclosed  in  a  second  membranous  envelope 
with  a  granular  yelk-like  fluid,  which  could  be  seen  pouring  out  when  the 
membrane  gave  way." 

The  reproduction  of  the  NoctUucida  is  as  yet  not  understood.  Quatrefages 
and  Krohn,  Prof.  Huxley  informs  us  {op.  cit.  p.  54),  "  consider  that  a  process 
of  fissiparous  multiplication  takes  place,  and  that  both  of  these  observers  have 
found  double  individuals,  though  very  rarely.  According  to  the  latter  writer, 
division  of  the  body  is  preceded  by  that  of  the  nucleus.  I  have  not  had  the 
good  fortune  to  meet  with  any  of  these  forms  ;  and  the  only  indication  of  a 


or  THE  PROTOZOA. NOCTILUCIDA.  385 

possible  reproductive  apparatus,  which  I  have  seen,  consisted  of  a  number  of 
granular  vesicular  bodies  of  about  -g- cnro^^  of  an  inch  in  diameter,  scattered  over 
the  sui'face  of  the  anterior  and  inferior  part  of  the  body."  Dr.  Webb  (op. 
cit.  p.  105)  has  the  following  observations  on  this  subject : — "  I  have  never 
met  with  a  double  individual,  but  on  one  occasion  witnessed  the  process  of 
di\*ision,  T\ithout,  however,  noting  any  proof  of  its  connexion  with  that  of 
fissiparous  multiplication.  Contractions  of  the  integument  took  place  in  such 
a  way  as  to  cut  off  a  globular  mass  from  the  body,  about  one-fourth  of  the 
whole.  The  two  portions  afterwards  retained  their  form,  with  a  puckered 
mark  at  the  point  of  separation.  The  nucleus  was  not  involved  in  this  ope- 
ration, which  occupied  about  two  hours. 

"  It  is  also  a  matter  of  eveiy-day  observation,  that  when  the  body  has 
been  torn  and  nearly  all  the  contents  have  been  lost,  the  animal  continues  to 
live  in  a  deformed  state,  if  the  nucleus  and  central  parts  are  left  together. 
They  acquire  a  new  investment ;  or  a  portion  of  the  original  integument 
gathers  up  round  them,  while  the  ragged  shreds  are  cast  off. 

''  When  several  of  these  creatiu-es  have  been  kept  for  some  time  in  still 
water,  it  is  not  unusual  to  find  two  of  them  in  apposition ;  but  I  have  never 
discovered  any  indications  of  conjunction,  and  look  upon  the  condition  as  one 
of  mere  adhesion.  It  may,  however,  have  given  rise  to  the  mention  of  double 
individuals,  as  the  adhesion  is  tolerably  firm.  It  may  easily  be  broken  up 
without  injury  to  either  animal.'' 

In  the  Journ.  of  Micr.  Science  for  1855,  p.  99,  is  the  translation  of  a  paper 
by  Dr.  Busch  on  the  structm-e  and  function  of  Noctiluca,  in  which  several 
original  observations  are  given  which  appear  to  bear  on  this  question  of  de- 
velopment. There  is,  however,  such  uncertainty  about  them,  and  the  want 
of  confirmatory  evidence,  that  we  deem  it  unnecessary  to  quote  them,  and  must 
therefore  refer  our  readers  to  the  Joui'nal  cited.  The  fom^th  volume  of  the  same 
excellent  periodical  (p.  74)  contains  a  translation  of  a  paper  by  Prof.  Miiller, 
from  which  it  appears  that  this  distinguished  naturalist  had  discovered  Nocti- 
luca in  an  encysted  condition.  The  account  he  gives  stands  thus  : — "  These 
encysted  bodies  constituted  the  principal  limiinous  animalcules  observed  at 
Messina  in  the  autumn  of  1853.  Free  NoctiluccB  at  that  season  were  not 
seen  there  ;  and  in  1849  the  same  kind  of  encysted  bodies  were  very  common 
at  Mce.  The  cyst  is  a  perfectly  transparent,  spheiical  capsule,  with  a  light - 
bluish  brilliancy  at  the  edge,  and  appearing  like  the  egg-membrane  of  some 
Cnistacea.  Within  this  cyst  is  lodged  a  body  in  all  respects  resembling  the 
Noctiluca  miliaris,  except  that  at  this  time  no  vibratile  filament  can  be  per- 
ceived. The  Noctiluca-Y\k.Q  creature  fills  the  cyst  more  or  less  entirely,  though 
occasionally  it  is  much  smaller.  In  this  condition  the  animalcules  are  lumi- 
nous without  being  agitated.  When  the  cysts  are  examined  under  the 
microscope  in  a  small  quantity  of  sea-water,  in  such  a  way  that  during  the 
observation  the  saline  contents  are  notably  increased  in  consequence  of  the 
evaporation,  a  moment  speedily  arrives  when  the  Noctilu€a-\ike>  body  sud- 
denly contracts  itself  within  its  case  into  a  little  nodule ;  that  is  to  say,  it 
contracts  upon  the  yellowish  granular  nucleus  from  which  the  filamentary 
strings  of  the  inteiior  proceed.  I  have  noticed  this  vital  phenomenon,  not 
on  one  occasion  only,  but  in  many  of  the  encysted  animalcules. 

''  The  size  of  the  case  is  usually  from  4'"  to  \"' .  But  many  are  far  smaller, 
even  down  to  -yV"-  Occasionally  also,  instead  of  a  Noctiluca,  cysts  may  be 
observed,  containing  a  yellow  nucleus  ■^"'  in  diameter  ;  and  once  I  noticed 
a  cyst  -^"'  in  size,  containing,  besides  this  rounded  yeUow  nucleus,  quite 
isolated,  an  extremely  minute  Noctiluca-Yike  body.  Of  the  free  Noctilucece 
taken  near  Heligoland  in  the  autumn,  the  smallest  were  ^"',  and  the  larger 

2c 


386  GENERAL  HISTORY  OF  THE  INFUSORIA. 

A  "  ^^  2%'  ^^  diameter.  The  common  variety  of  form,  with  a  constriction 
of  the  circumference,  which  is  noticed  in  free  Noctilucce,  and  the  radiating 
filamentary  branching  striae  beset  with  extremely  minute  granules  in  the 
interior,  were  also  characteristic  of  the  encysted  bodies,  which  1  should  be 
more  indisposed  to  separate  from  the  Noctilucce,  from  their  possessing  the 
most  remarkable  luminous  power.  At  present  we  want  the  key  to  these  re- 
remarkable  phenomena,  as  well  as  all  knowledge  of  the  development  and 
course  of  life  of  the  Noctilucce.'' 

We  have,  in  our  prefatory  observations  on  this  family,  alluded  to  the 
opinion  of  the  affinity  of  Noctilucicla  with  Ciliated  Protozoa.  Prof.  Huxley 
(op.  cit.  p.  54)  has  the  following  notes  on  this  subject : — "  If  the  preceding 
account  be  correct,  it  is  obvious  that  the  animal  is  no  Ehizopod,  but  must  be 
promoted  from  the  lowest  rank  of  the  Protozoa  to  the  highest.  The  exist- 
ence of  a  dental  armature  and  of  a  distinct  anal  aperture,  are  structural 
peculiarities  which  greatly  increase  the  affinity  to  such  forms  as  Colpoda 
and  Paramecium,  indicated  by  KJrohn.  Noctiluca  might  be  regarded  as  a 
gigantic  Infusorium  with  the  grooved  body  of  Colpocla,  the  long  process  of 
Trachelius,  and  the  dental  armatui'e  of  Nassula  united  in  one  animal. 

"  On  the  other  hand,  the  general  absence  of  cilia  over  the  body,  and  the 
wide  differences  in  detail,  would  require  the  constitution  of  at  least  a  distinct 
family  for  this  singular  creature." 

To  our  apprehension  there  is  no  homology  between  the  dental  armature  of 
Noctiluca  and  of  Nassula.  In  the  latter,  the  so-called  teeth  appear  to  be 
nothing  more  than  hardened  folds  of  the  membranous  tube  of  the  oesophagus, 
which  may  disappear  by  distension, — whilst  in  Noctiluca  it  is  the  condensed 
uncinate  margin  of  the  oral  cavity  on  one  side  which  constitutes  the  dental 
apparatus.  Again,  as  to  the  presence  of  a  distinct  anal  aperture,  this  cer- 
tainly estabHshes  no  other  affinity  with  the  higher  Ciliata  than  it  does  with 
any  other  microscopic  animalcules  which  possess  such  an  outlet.  On  the 
contrary,  there  is  force  in  the  particulars  mentioned  as  opposed  to  their  re- 
lation with  the  Ciliata,  viz. ''  the  general  absence  of  cilia,  and  the  wide  differ- 
ences in  detail;"  for  cilia  either  diffused  over  the  body,  or  collected  into 
groups  to  form  a  special  ciliary  organ,  are,  when  taken  in  connexion  with 
the  peculiar  internal  organization,  so  very  characteristic  that  no  microscopist, 
unbiassed  by  imagination,  would  reckon  Noctiluca  among  Cihata.  In  further 
opposition  to  the  notion  of  such  an  affinity,  it  may  be  urged  that  Noctiluca  is 
destitute  of  a  ciliated  contractile  oesophagus,  and  of  a  contractile  vesicle, 
that  it  does  not  produce  vacuoles  in  the  introduction  and  transmission  of  food, 
and  that  its  so-called  vacuoles  appear  to  be  actual  closed  sacs,  separable  from 
the  body.  Other  distinctive  peculiarities  between  the  two  might  be  ad- 
duced ;  but  we  think  that,  on  reflection  and  a  comparison  between  them,  ob- 
servers will  agree  with  us  that  Noctiluca  is  not  a  member  of  the  Ciliated 
Protozoa,  that  it  cannot  be  included  among  them  as  a  new  family,  but  must 
be  placed  in  some  other  class  of  animalcules,  or  of  itself  form  the  representa- 
tive of  a  new  class. 

The  Noctilucicla  are  inhabitants  of  the  ocean,  of  the  luminosity  of  which 
they  seem  to  be  the  most  potent  cause,  of  the  many  which  have  been 
foimd  in  operation.  They  occur  in  the  British  seas,  as  well  as  elsewhere, 
floating  on  the  surface  of  the  water.  Mr.  Byerly,  of  Liverpool,  noticed 
their  prevalence  in  such  numbers  that  the  water  acquired  a  rose-colour ; 
and  Dr.  Webb  (op.  cit.  p.  102)  intimates  that  their  luminosity  must  depend 
on  some  pecuhar  condition  of  their  organs,  or  the  media  acting  upon  them. 
This  supposition  is  analogous  to  that  made  by  Ehrenberg  respecting  the 
phosphorescence  of  the  Periclinicea,  which  he  believed  to  be  due  to  what  he 


OF  THE  PROTOZOA. DYSTERIA.  387 

termed  the  ^'  ovaries,"  or  the  masses  of  brownish-red  matter  which  sometimes 
nearly  fill  the  interior.  Perhaps  the  brown  granular  matter  which  at  times 
accumulates  in  and  about  the  nucleus  of  Noctiluca,  and  which  is  probably- 
related  to  the  reproductive  function,  is  the  luminous  material  in  this  ani- 
mal ;  and  there  is  nothing  contrary  to  analogy  in  supposing  the  development 
of  phosphorescence  to  be  associated  with  a  particular  period  of  vital  activity, 
but  rather  everytliing  in  its  favour.  The  following  valuable  note  on  the 
collection  of  specimens  occurs  in  Dr.  Webb's  excellent  paper  {op.  eit.  p.  102) : 
— "As  a  caution  to  those  who  may  undertake  the  further  examination,  I  may 
state  that  the  buoyancy  of  the  Noctiluca  is  such  as  to  bring  it  to  the  surface 
of  tranquil  water  without  any  apparent  effort,  and  that  the  best  way  to 
effect  its  capture  is,  not  as  is  most  frequently  done,  to  use  the  muslin  net,  by 
which  means  the  greater  number  of  the  creatui'es  are  lost  or  destroyed,  but 
to  skim  the  top,  and  especially  those  parts  near  the  sides  of  the  vessel  in 
which  the  water  has  been  standing.  If  removed  in  this  way,  and  kept  by 
themselves  in  a  test-tube,  they  may  be  preserved  for  two  or  three  weeks 
without  a  fresh  supply  of  water.  Even  at  the  end  of  that  time,  if  they  die, 
it  does  not  appear  to  be  from  having  reached  the  natural  term  of  their  ex- 
istence, but  as  the  result  of  some  accidental  cause ;  they  will  not,  however, 
bear  carriage  to  any  great  distance  in  closed  vessels." 

We  gather  the  following  hints  for  the  capture  of  Noctilucida  from  a  paper 
by  Col.  Baddeley  {T.  M.  S.  1858,  p.  79)  -.—"Attach,"  he  says,  "  a  fine  muslin 
net  to  the  end  of  a  light  pole,  and  proceed  to  some  spot  where  the  Noctilu- 
cida are  likely  to  be  driven.  A  breakwater  which  causes  an  eddy  to  collect 
Medusce,  (fee.  generally  yields  a  good  harvest.  Skim  the  sui'face,  and  wash 
the  net  repeatedly  in  a  can  of  salt  water.  At  night  these  creatures  are  easily 
seen  by  their  luminosity ;  by  day,  if  plentiful,  they  cover  the  surface  of  the 
sea  in  brownish  streaks ....  The  best  winds  in  which  to  capture  these  crea- 
tures appear  to  be  those  from  south  to  west ;  during  their  prevalence,  I 
have  taken  Noctilucce  every  month  of  the  year  on  the  east  coast  of  England ; 
but  it  is  during  the  summer  months  they  are  most  abundant,  and  during 
calm  weather.  Abroad,  they  are  constantly  to  be  met  with  in  warm  lati- 
tudes ;  and  I  feel  confident  some  interesting  results  might  be  obtained  by 
securing  these  creatures  in  various  parts  of  the  world."  In  conclusion  he 
refers  to  the  Diatomece  which  are  so  commonly  found  in  considerable  quantities 
in  their  interior. 

FAMILY  III.— DYSTERIA. 
(Plate  XXXI.  Figs.  24-27.) 

Dysteria,  which  is  clearly  the  type  of  a  new  family  of  animalcules,  was  so 
named  by  Prof.  Huxley  in  honour  of  its  discoverer,  Mr.  Dyster.  Although 
its  exact  systematic  position  and  afiinity  are  not  agreed  upon,  it  certainly 
occupies  a  position  in  the  zoological  scale  above  the  Ciliata,  if  it  does  not 
rightly  take  its  place,  as  Mr.  Gosse  contends,  among  the  Rotatoria. 

As  we  have  unfortunately  no  knowledge,  personally,  of  this  interesting 
being ;  we  must  avail  ourselves  of  the  excellent  description  afforded  by  Prof, 
Huxley  {J.  M.  S.  1857,  p.  78),  and  of  the  critical  examination  of  its  affinities 
furnished  by  Mr.  Gosse  (ibi^l.  p.  138). 

"  Dysteria  armata  has  an  oval  body,  ^b^^  ^^  TOT^^  ^^  ^^  'va.Qh.  long,  by 
ji^th  to  -^^th  broad,  which  is  not  altogether  sjnnmetrical — the  one  side 
presenting  a  considerable  evenly-rounded  convexity,  while  the  other,  less 
prominent,  is  divided  by  an  angulated  longitudinal  ridge  into  a  smaller, 
dorsal,  and  a  larger,  ventral  area.     The  edges  of  both  lateral  surfaces  are 

2c2 


388  GENERAL  HISTORY  OF  THE  INFUSORIA. 

sharp  and  thin ;  dorsally  they  are  separated  by  a  shallow  groove  ;  but  along 
the  ventral  line  of  the  body  the  groove  is  deep  and  narrow,  and  the  produced 
edges  of  the  lateral  parietes  resemble  the  valves  of  a  bivalve  shell. 

*'  The  ventral  and  dorsal  grooves  pass  into  one  another  in  front ;  but  pos- 
teriorly the  lateral  edges  are  united  for  a  short  space.  The  edge  of  the  left, 
less  convex,  side  of  the  body  ends  anteriorly  in  an  obtuse  point,  which  cor- 
responds with  the  anterior  termination  of  the  angulated  ridge,  and  does  not 
extend  by  any  means  so  far  forward  as  the  edge  of  the  right  side,  which  re- 
mains thin,  and  forms  the  anterior  extremity  of  the  body. 

"  At  the  anterior  extremity,  the  large  oral  aperture  is  seen,  just  below  the 
angulated  ridge,  and  occupying  the  bottom  of  a  deep  fossa,  which  here  takes 
the  place  of  the  dorsal  and  ventral  grooves.  The  left  wall  of  this  fossa  is 
thickened,  and  projects  inwards  so  as  to  form  a  cushion-like  lobe,  clothed 
with  remarkably  long  cilia ;  and  these  cilia  are  continued  into  the  oral  aper- 
ture itself, — the  posterior  ones  being  large,  usually  directed  transversely  to 
the  axis  of  the  body,  and  having  at  times  much  the  appearance  of  vibratile 
membranes. 

''  The  bottom  of  the  oral  fossa  is  strengthened  by  a  curious  curved  rod, 
which  terminates  superiorly  in  a  bifid  tooth,  while  inferiorly  it  appears  to 
become  lost  in  the  wall  of  the  fossa. 

"  But  there  is  a  much  more  prominent  and  easily  distinguishable  apparatus 
of  hard  parts  situated  on  the  opposite  or  ventral  side  of  the  mouth,  and  ex- 
tending thence  through  two-thiixls  of  the  length  of  the  body.  It  consists  of 
two  portions — an  anterior,  somewhat  rounded  mass,  in  apposition  with  a 
much  elongated,  styliform,  posterior  portion. 

"  It  is  very  difficult  to  assure  oneself  of  the  precise  structure  of  the  ante- 
rior portion ;  but  it  would  seem  to  be  a  deep  ring,  composed  of  three  pieces — 
two  supero-lateral  and  mutually- corresponding,  united  with  a  third,  inferior, 
azygos  portion.  The  latter  is  somewhat  triangular,  ^ith  a  broad  base  and 
rounded  obtuse  apex, — the  latter  being  directed  forwards,  and  immediately 
underlying  the  oral  aperture,  while  the  former  is  tiuned  backwards,  and 
unites  with  the  two  supero-lateral  pieces.  Each  of  these  is  concave  inter- 
nally, and  convex  externally,  so  as  to  form  a  segment  of  a  circle,  and  presents 
a  clear  median  space,  the  optical  expression  either  of  a  perforation  or  of  a 
much-thinned  spot. 

"  The  anterior  edge  of  each  supero-lateral  piece  is  nearly  straight ;  but  the 
posterior  is  convex,  and  it  is  by  this  edge  that  it  articulates  with,  or  is  ap- 
posed to,  the  anterior  extremity  of  the  posterior  division  of  the  apparatus. 
Viewed  laterally,  this  posterior  portion  appears  to  consist  of  two  styles, 
which  are  somewhat  like  nails  in  shape, — their  anterior  extremities  being 
truncated,  so  as  to  present  a  sort  of  nail-head,  while  the  posterior  ex- 
tremity seems  to  taper  to  a  fine  point.  Rather  in  front  of  the  middle  of  its 
inferior  edge  each  style  seems  to  give  off  a  short  process  downwards ;  and 
this  process  is,  in  botanical  language,  deciuTent  upon  the  style.  Careful 
examination  of  the  dorsal  or  ventral  aspect  of  these  parts  shows  that  the 
decurrent  process  is,  in  fact,  only  the  expression  of  a  delicate  membrane,  which 
is  bent  so  as  to  have  a  ventral  convexity,  and  connects  together  the  two 
styles.  It  might  be  said,  therefore,  that  the  posterior  part  of  the  apparatus 
is  a  triangular  membrane,  deeply  excavated  in  front,  bent  so  as  to  be  convex 
downwards,  and  having  its  margins  thickened  and  produced  into  styliform 
enlargements.  This  curious  piece  of  mechanism  is  directed  upwards  and 
backwards,  and  terminates  in  the  substance  of  the  body  without  any  apparent 
connexion  with  other  parts. 

*'  The  whole  apparatus  is  moveable.  The  posterior  portion  is  pushed  against 


OF  THE  PEOTOZOA. DYSTEKIA.  389 

the  anterior ;  and  the  heads  of  the  styles  come  into  contact  A\ith  the  posterior 
convex  edges  of  the  supero-lateral  pieces,  and  push  them  forwards ;  the 
posterior  portion  is  then  retracted,  and  the  whole  apparatus  returns  to  its 
previous  arrangement. 

"  In  one  Dysteria,  which  had  swallowed  a  filament  of  Oscillator'm  so  long 
that  the  one  extremity  projected  from  the  mouth  when  the  other  was  as  far 
back  in  the  body  as  it  could  go,  these  movements  took  place  as  many  as 
twenty  times  in  a  minute. 

^'  Mr.  Dyster  fui'ther  informs  me  that  in  one  of  these  animals  which  he 
saw  feed,  the  frond  of  OsciUatoria  was  rather  '  swum  upon '  than  seized — 
ingestion  being  accomjDlished  by  a  smooth  gliding  motion,  apparently  without 
displacement  of  the  styles, — but  that,  when  the  act  was  completed,  the  styles 
^  gave  a  kind  of  snap  and  moved  slightly  forwards.' 

"  Mr.  Dyster  is  inclined  to  think  that  the  OsciUatoria  passed  through  the 
anterior  ring-like  portion  of  the  apparatus.  I  have  not  seen  the  animal  feed, 
but,  on  structural  grounds,  I  should  rather  have  been  inchned  to  place 
the  oral  aperture  at,  and  to  suppose  that  the  food  would  pass  above,  the 
anterior  ring.  The  apparatus  is  destroyed  by  caustic  potash,  but  remains 
imaltered  on  the  addition  of  acetic  acid ;  it  is  therefore  probably  entirely 
composed  of  animal  matter. 

"  Immediately  above  the  annular  portion  of  the  apparatus,  there  is  inva- 
riably present  a  remarkable  amethyst-coloured  globule,  apparently  composed 
of  a  homogeneous  fluid.  It  has  on  an  average  a  diameter  of  ^^p^-jj  in.,  and 
it  is  entii'ely  lodged  in  the  more  convex  portion  of  the  body.  In  many  spe- 
cimens no  other  colouring  matter  than  this  can  be  detected ;  but  in  some, 
minute  granules  (y^-^nro  ^^0  ^^  ^  similar  colour  are  scattered  through  the 
body.  AVhat  connexion  these  have  with  the  large  constant  globule  is  not 
clear,  since,  although  the  dimensions  of  the  latter  vary  from  the  size  given 
above  to  one-fom^th  or  less,  no  relation  could  be  observed  between  this 
diminution  and  the  presence  of  the  granules  in  other  parts  of  the  body. 

"  Behind  the  amethystine  globule,  the  substance  of  the  body  has  the  ap- 
pearance, common  to  the  Infusoria  generally,  of  a  mass  of  '  sarcode,'  in 
which  the  ingested  matters  are  imbedded,  and  no  clear  evidence  could  be 
obtained  of  the  existence  of  any  digestive  ca\ity  with  distinct  walls. 

"  A  little  behind  the  middle  of  the  body,  and  towards  its  ventral  edge, 
there  is  a  clear  spheroidal  *  contractile  space/  which  varies  a  good  deal  in 
size.  One  measured  ^ -\^^th  of  an  inch  in  diameter,  and  became  entirely 
obhterated  in  the  contracted  state. 

''  The  contractions  are  not  rhythmical,  but  take  place  iiTCgularly.  On  the 
approach  of  death,  the  space  becomes  irregularly  and  enormously  enlarged, 
imtil  it  occupies  perhaps  a  third  of  the  whole  contents  of  the  body. 

"  Immediately  beyond  the  contractile  space  there  is  a  curious  oval  body, 
having  its  long  axis  ( -  ^^^  ^^  in.)  directed  upwards,  and  containing  a  compara- 
tively small  central  ca\ity,  so  that  it  appears  like  a  thick- walled  sac. 

*'  Indications  strongly  suggestive  of  an  inferior  opening  were  sometimes 
observed  in  this  body  ;  but  no  demonstrative  eridence  of  the  existence  of  any 
such  aperture  could  be  obtained. 

"  The  walls  of  the  ventral  groove  are  provided  mth  long  and  powerful 
cHia — a  remarkably  strong  one  being  attached  behind  the  base  of  the 
*  appendage ; '  and  by  their  means  the  animal,  when  free,  is  propelled  at 
no  very  rapid  rate  through  the  water.  Its  more  usual  habit,  however,  is 
to  remain  fixed  by  means  of  the  peculiar  appendage  ;  and  then  the  cilia  act 
merely  in  creating  currents,  by  which  nutritive  matters  are  brought  towards 
the  mouth. 


390  GENERAL  HISTORY  OF  THE  INFUSORIA. 

"  The  appendage  referred  to  is  attached  to  the  surface  of  the  body,  rather 
towards  the  convex  side,  at  the  bottom  of  the  ventral  groove,  and  is  distant 
about  one-fifth  of  the  whole  length  from  the  posterior  extremity.  It  is 
-g^th  to  Y^jL_th  of  an  inch  in  length,  and  is  not  altogether  unlike  a  boot 
with  a  veiy  pointed  toe  in  shape ;  and  the  toe  appears  to  be  viscid  at  its 
extremity,  so  as  readily  to  adhere  to  any  foreign  object.  The  appendage 
then  forms  a  pivot  on  which  the  whole  body  turns  about ;  and  this  appears  to 
be  the  habitual  and  favoimte  position  of  the  Dysteria. 

"  Internally,  the  appendage  contains  a  canal,  mder  above  than  below,  and 
apparently  bhnd  at  each  extremity. 

"  No  '  nucleus  '  could  be  found,  though  carefully  sought  for  with  the  aid 
of  acetic  acid. 

"  The  occurrence  of  transverse  fission  was  noticed  veiy  distinctly  in  one 
case  ;  but  it  is  remarkable  that,  notwithstanding  the  great  number  of  speci- 
mens which  were  observed,  no  other  instance  of  this  mode  of  multiplication 
came  under  the  notice  of  Mr.  Dyster  or  myself.  It  would  appear  that  the 
*  apparatus '  disappears,  and  is  reproduced  during  fission ;  for,  in  the  single 
case  observed,  mere  rudiments  of  it  were  to  be  seen  in  each  half  of  the 
strongly-constricted  mass. 

'^Dysteria  has  not  hitherto  been  observed  to  become  encysted,  although 
this  condition  has  been  carefully  sought  for. 

"  The  creatm-e  was  foimd  in  swarms  among  the  Algae,  coating  the  shells 
of  a  Patella  and  a  Littorina  which  had  long  inhabited  a  marine  vivarium. 

"  There  can  "  (p.  82)  "  be  little  doubt  as  to  the  true  systematic  position 
of  Dysteria.  The  absence,  in  an  animal  which  takes  solid  nutriment,  of  an 
alimentary  canal  Tvdth  distinct  walls,  united  with  the  presence  of  a  contrac- 
tile vesicle,  with  the  power  of  transverse  fission,  and  with  cilia  as  locomotive 
organs,  is  a  combination  of  charactei's  found  only  in  the  Infusoria.  In  this 
class,  again,  the  existence  of  a  sort  of  shell  or  lorica,  constituted  by  the 
structui^eless  outer  layer  of  the  body ;  the  presence  of  a  submarginal  ciliated 
groove  around  a  large  part  of  the  margins  of  the  body ;  and  the  inequality 
of  the  two  lateral  halves,  leave  no  alternative  save  that  of  arranging  Dysteria 
near  or  in  the  Euplota  of  Ehrenberg. 

"  Indeed,  there  is  one  species  figured  by  Ehrenberg  {Infusionstliierchen, 
p.  480,  pi.  42.  fig.  14),  Euplotes  macrostylus,  found  at  Wismar,  on  the  Baltic, 
which,  in  general  aspect,  and  in  the  possession  of  a  foot-like  appendage, 
so  closely  resembles  the  present  form,  that,  were  it  not  for  the  absence  of 
any  allusion  to  the  amethystine  globule,  or  to  the  '  apparatus,'  I  should  be 
strongly  inclined  to  think  it  identical  with  Dysteria.  That  an  internal 
armature  is  not  inconsistent  with  the  general  plan  of  the  Euplota,  is  shown 
by  Chlamidodon,  whose  apparatus  of  styles  would  probably  repay  re-exami- 
nation. 

"  Notwithstanding  certain  analogies  which  might  be  shown  to  exist  be- 
tween the  manducatory  apparatus  of  some  Rotifera  (see,  e.  g.,  that  of  Furcu- 
laria  mariyia,  figured  by  Mr.  Gosse,  in  his  excellent  memoir,  Phil.  Trans. 
1846)  and  the  *  apparatus  '  of  Dysteria,  1  see  no  grounds  for  regarding  the 
latter  as  in  any  way  an  annectant  form  between  these  groups." 

Mr.  Gosse  dissents  from  this  conclusion  of  Prof.  Huxley  relative  to  its 
connexion  with  Euplota,  and  considers  it  a  member  of  the  family  Monocer- 
cadece  among  the  Rotifera. 

"  Presuming,"  he  says  (J.  M.  S.  1857,  p.  138),  "  Dysteria  to  be  an  In- 
fusorium, it  must  be  a  species  sui  generis,  with  no  close  affinity  with  the 
Euplotidce.  An  animal  whose  soft  parts  are  enclosed  between  two  deeply- 
cowpressed  valves,  and  which  crawls  by  the  aid  of  a  hinged  shelly  foot,  is 


OF  THE  PROTOZOA. DYSTEEIA.  391 

widely  diiferent  fi'om  one  greatly  depressed,  covered  with  a  dorsal  plate,  and 
whose  organs  of  locomotion  are  short  flexible  setae  scattered  over  the  soft 
ventral  surface. 

"  But  I  am  by  no  means  sure  that  it  should  be  placed  among  the  Infusoria 
at  all.  Mr.  Huxley  observes  that  '  the  absence,  in  an  animal  which  takes 
soHd  nutriment,  of  an  alimentary  canal  with  distinct  walls,  united  with  the 
presence  of  a  contractile  vesicle,  with  the  power  of  transverse  fission,  and 
with  ciHa  as  locomotive  organs,  is  a  combination  of  characters  found  only  in 
the  Infusoria. 

^'  Now  the  presence  of  a  contractile  vesicle,  and  of  locomotive  cilia,  are 
quite  as  characteristic  of  the  Eotifera  as  of  the  Infusoria.  The  absence  of 
an  ahmentary  canal  is,  I  think,  not  proved :  it  seemed  to  me  that  the  animal 
possessed  a  defined  digestive  cavity,  though  very  ample.  In  Sacculus — an 
indubitable  Rotiferon,  which  carries  its  large  eggs  in  the  manner  of  a  Bra- 
chionus — the  alimentary  canal,  without  apparent  distinction  of  stomach  and 
intestine,  is  so  large  that  it  occupies  fully  five-sixths  of  the  whole  volume  of 
the  lorica ;  and  though  it  is  invariably  found  filled  with  a  green  Alga,  on 
which  the  animal  feeds,  the  walls  of  the  digestive  cavity  are  not  better  defined 
than  in  Dysteria.  There  remains,  then,  only  the  fact  of  increase  by  trans- 
verse fission.  This,  I  confess,  is  a  strong  point,  if  well  estabhshed.  But  it 
does  not  seem  certain,  fi'om  Mr.  Huxley's  words,  whether  he  witnessed  the 
progress  of  constriction  from  an  early  stage  until  two  perfect  animals  were 
formed  out  of  one,  or  only  saw  an  individual  so  strongly  constricted  that  the 
result  seemed  legitimately  inferable.  If  the  latter  was  the  case,  is  it  not  just 
possible  that  it  was  an  example,  not  of  spontaneous  fission,  but  of  malforma- 
tion, instances  of  which  are  frequent  among  the  highest  animals  ?  It  is  highly 
worthy  of  note  that  the  nucleus,  so  characteristic  of  the  Infusoria,  was  not 
found,  even  under  carefid  search  with  acetic  acid. 

"  The  presence,  position,  and  movements  of  the  foot,  hinged  as  it  is  upon 
a  tubercle,  and  the  form  of  the  principal  organs  of  manducation,  seem  to  me 
to  determine  the  place  of  Dysteria  within  the  class  Rotifera ;  while,  at  the 
same  time,  the  lack  of  internal  motion,  the  apparent  want  of  distinct  muscle- 
bands,  the  great  extent  of  the  vibratory  ciha,  and  the  absence  of  a  rotatory 
arrangement,  show  that  it  occupies  one  of  the  vanishing  points  of  the  class." 

Mr.  Gosse  next  proceeds  to  examine  to  which  group  of  Rotatoria  it  ap- 
proaches most  nearly,  and  concludes,  as  above  intimated,  that  it  ought  to 
have  a  place  in  the  family  Monoceyxadece,  represented  by  the  genera  Mono- 
cerca  and  Mastigocerca,  although,  at  the  same  time,  a  very  aberrant  genus. 
He  adds  "  that  it  has  also  remote  relations  with  the  Salpinadce,  and  especially 
with  the  Coluridce  (through  Monura)  ;  and  that  it  is  an  annectant  form  be- 
tween the  Eotifera  and  the  Infusoria  {i.  e.  the  Ciliata),  with  a  preponderance 
of  the  characters  of  the  former  class." 


392  GENERAL  HISTORY  OF  THE  INFUSORIA. 


Sect.  IV.— OF  THE  ROTATORIA  OR  ROTIFERA. 
(Plates  XXXII.-XL.). 

General  Characters. — Symmetrical  animals,  having  a  distinct  head  and 
body ;  the  former  sui-mounted  by  a  wreath  of  cilia,  the  latter  presenting 
transverse  folds  or  joints,  with  a  simple  alimentary  canal  and  internal  maxil- 
lary apparatus ;  a  muscular  and  a  water-vascular  system ;  nerves  and  nervous 
ganglia,  but  not  arranged  in  a  symmetrical  chain ;  reproductive  organs  sepa- 
rate in  opposite  sexes ;  and  propagation  without  imdergoing  actual  metamor- 
phosis, by  ova  of  two  forms.  The  Rotatoria,  moreover^  are  destitute  of  limbs 
in  pairs,  but  have  mostly  the  posterior  extremity  of  the  body  produced  as  a 
powerful,  although  a  symmetrical,  organ  of  locomotion,  in  which  a  transverse 
articulation  is  particularly  evident. 

This  is  a  very  natural  gToup  of  animals, — its  characters  being  definite,  and 
readily  recognized  by  reason  of  the  comparatively  large  size  and  transparency 
of  the  organisms.  The  name  Uotatoria,  sometimes  exchanged  for  Rotifer  a, 
is  derived  from  the  apparent  whirling  or  wheel  (rofa)-like  motion  of  the 
ciliary  wreath  aroimd  the  head,  seen  in  most  species.  Since  this  rotary 
movement  is  not  universal,  and  at  best  but  an  ocular  deception,  some  ob- 
servers have  been  discontent  with  the  appellations  derived  therefrom ;  and 
Dujardin,  for  one,  has  suggested  as  preferable  the  term  *  Sysiolides/  as 
indicative  of  the  remarkable  contractile  and  flexible  nature  of  their  bodies. 
They  are  also  still  spoken  of  imder  the  old  name  of  '  wheel-animalcules ; ' 
indeed,  the  early  observers  of  the  class  actually  believed  the  animals  to  be 
furnished  with  wheels,  by  the  rotation  of  which  they  moved. 

External  Form,  Integument,  and  Appendages. — The  Rotifera  are  symme- 
trical, and  in  this  respect  contrast  with  the  asymmetrical  Protozoa.  They 
present  a  determinable  dorsal  and  abdominal  surface,  and  consequently  a  right 
and  a  left  side.  They  have  an  oblong,  ovoid,  or  much-elongated  figure,  and 
are  mostly  separable,  by  the  presence  of  a  constriction  more  or  less  developed, 
into  an  anterior  segment  or  head,  alid  a  larger  posterior  one  or  trunk.  The 
extension  of  the  latter  in  a  tail-like  fashion  may  be  regarded  as  a  third  seg- 
ment. The  constriction  or  narrower  portion  behind  the  head  is  frequently 
called  the  neck  ;  this  is  wanting  in  many  cases,  and  then  the  head  is  undistin- 
guishable  from  the  trunk  as  a  distinct  section,  e.  g.  in  Notommata  Myrmeleo. 
On  the  contraiy,  the  separation  of  the  head  from  the  trunk  is  weU  seen  in 
Brachionus  (XXXIX.  15-18;  XL.  11),  Steplianops  (XL.  8-10),  Euchlanh 
(XXXIX.  4),  Noteus  (XXXVIII.  25),  and  Melicerta  (XXXYIL  17).  The 
articulation  of  the  tail-like  segment  is  always  evident.  In  a  certain  number 
this  prolongation  is  wanting ;  and  the  animal  is  then  tailless, — e.  g.  Anurcea 
(XXXV.  495-498)  and  SaccuJus  (XXXIX.  18). 

To  facilitate  the  recognition  of  the  general  divisions  of  the  body  of  Rotatoria, 
considered  as  bilateral  symmetrical  animals,  Mr.  Gosse  furnishes  the  following 
remarks  (Phil.  Trans.  1855,  p.  424) : — The  bilateral  organization  is,  he  ob- 
serves, in  most  cases  "  obvious, — the  motions  of  the  animal,  like  those  of  the 
footed  larvse  of  insects,  being  performed  on  the  belly,  with  the  head  foremost. 
Where  this  is  not  the  case  (as  T\ith  those  genera  which,  either  with  or  with- 


OF  THE  EOTATOKIA.  393 

out  an  enveloping  tube,  adhere  to  foreign  substances  by  the  tip  of  the  foot, 
and  elevate  the  body  in  an  erect  position),  the  dorsal  aspect  is  always  deter- 
minable by  the  eye  or  eyes  being  towards  that  sui^face,  by  the  stomach  and 
intestine  passing  do^vn  it,  and  by  the  cloaca  being  on  that  side  of  the  foot. 
The  ventral  aspect  has  the  manducatory  apparatus  and  the  ovary." 

But,  besides  these  great  divisions,  all  the  Eotifera  exhibit  transverse  lines, 
folds,  or  joints,  analogous  to  those  seen  in  the  Articulata,  especially  among 
the  Cnistacea,  such  as  the  lobster  and  shrimp.  Mostly,  such  are  but  folds  or 
wiinldes,  and  not  true  articulations,  in  the  Rotatoria  (though  perhaps  as  much 
so  as  the  like  in  the  larvae  of  many  insects),  and  consequently  disappear  on 
the  extension  of  the  animals.  However,  in  not  a  few  instances,  veritable 
articulations  occm% — e.  g.  Hydatina,  Rotifer,  Eosjpliora,  PhUocUna  (XXXYIII. 
1,  2).  In  Eiwhlanis  dilatata,  writes  Ehrenberg,  the  abdominal  surface  pre- 
sents four  decided  articulations.  The  minimum  development  of  the  articulate 
condition  occurs  in  those  genera  the  most  removed  from  the  liotatorial  type, 
viz.  in  Stej^hanoceros  (XXXVII.  1),  Lacimdaria  (XXXVII.  19),  and  some 
anomalous  Notommata  (XXXVIII.  28),  which  only  present  fine  lines  under 
the  surface,  looking  like  annular  threads.  The  construction  of  the  joints  is 
peculiar,  one  portion  or  segment  sliding  within  another  after  the  manner  of 
the  tubes  of  a  telescope.  This  telescopic  action  is  best  illustrated  in  the 
genus  Philodina,  where  the  entii^e  body  is  fusiform  and  articulated  ;  but  it  is 
oftentimes  to  be  seen  also  in  the  tail-process,  when  absent  or  imperfect  in 
the  rest  of  the  body, — e.  g.  Brachioniis,  Noteus  (XXXVIII.  25),  StepTianops 
(XL.  8-10),  Scaridkmi  (XXXVIII.  22).  An  incomplete  articulation,  or 
mere  wrinkling,  is  seen  in  the  pedicle  of  Megcdotroclia,  Melicei^ta,  and  Lacinu- 
lana  (XXXVII.  17-19). 

AH  the  Rotatoria  are  invested  by  a  fii-m,  usually  smooth  and  elastic, 
integument  or  skin,  which  follows  the  contained  parenchpna  in  all  its  con- 
tractions, accommodating  itself  to  the  various  movements  of  the  body.  It  is 
more  delicate  on  the  head,  where  the  cilia  are  inserted,  and  there  becomes 
continuous  ^\ith  the  membrane  of  the  interior.  It  is  composed  of  two  layers 
— an  external,  the  cuticle,  and  an  inner,  immediately  subjacent,  the  dermis 
(XXXVIII.  2Q).  'WTiere  the  structiu'e  is  not  evident,  it  may  be  rendered  so 
by  the  use  of  chromic  acid.  The  cuticle  is  homogeneous,  structureless,  and 
firmer  than  the  dermis,  which  is  soft,  granular,  and  contains  in  its  thickness 
numerous  fat-globules  and  nucleated  particles  (XXXVII.  29).  The  latter 
tissue  acts  as  a  lining  to  the  general  cavity  of  the  body,  and  gives  attachment 
to  the  muscular  cords  of  the  interior.  It  is  much  developed  about  the  head, 
beneath  the  vibratile  ciliaiy  apparatus,  and  there  sends  inwards  numerous 
projections  or  lobes  (XL.  2),  which  Ehrenberg  assimied  to  be  of  a  muscular 
nature,  and  to  be  permeated  by  vessels  and  nerves.  At  other  parts  also, 
dehcate  fibres  or  threads  are  seen  to  pass  inwards  from  the  dermis  to  the 
\iscera,  sustaining  and  connecting  them  together.  These  fibres  have  some- 
times been  described  as  muscles,  at  other  times  as  nerves.  The  former  is 
apparently  their  true  nature,  although,  as  Cohn  believes,  nerve-fibres  may  be 
mixed  among  them. 

The  integument  is  histologically,  i.  e.  in  its  anatomical  nature,  a  connective 
tissue  derived  from  the  coalescence  of  branching  cells,  and  still  presents  in 
its  inner  layer  the  scattered  nuclei  of  the  original  cells,  in  the  form  of  the 
nucleated  particles  described.  Where  the  dermis  is  much  developed,  its  soft 
tissue  becomes  here  and  there  hollowed  out  into  clear  spaces  or  vacuoles, 
which  have  been  mistaken  for  nerve -ganglions,  especially  when  situated  in 
the  head  (XXXVII.  29).  8o,  again,  at  the  posterior  part  of  the  body, 
behind  the  viscera,  and  in  its  prolongation  or  foot-process,  where  the  dermic 


394  GENERAL  HISTORY  OF  THE  INFUSORIA. 

tissue  abounds,  the  vacuolar  thickenings  have  been  conceived  to  represent 
ganglions  or,  otherwise,  glands. 

The  cuticle,  or  external  limiting  membrane  of  the  integument,  is  hardened 
by  the  deposition  in  it  of  the  peculiar  chemical  principle  chitine,  the  same 
which  imparts  firmness  to'  the  covering  of  Entomostraca,  Insects,  and  other 
Articulata  ;  or  if  not  actually  chitine,  it  is  a  substance  closely  allied  thereto. 
This  is  Leydig's  opinion,  and  it  seems  sufficiently  confirmed  by  the  reaction 
of  chemical  agents.  Thus,  he  shows  that  caustic  alkali  (potash)  does  not  dis- 
solve the  cuticle  when  it  possesses,  as  it  usually  does,  moderate  firmness,  in 
other  words,  when  an  infusion  of  chitine  exists  in  its  substance.  But  when 
the  animal  lives  within  an  external  case,  and  does  not  need  the  protection  of 
an  immediately  investing  skeleton,  the  chitine  is  absent,  and  the  integument 
dissolves  in  the  alkali.  The  analogue  of  this  may  be  found  among  the 
Articulata. 

The  prevalent  opinion  has  been,  that  the  dense  cuticle  or  external  skeleton 
of  Rotifera  differed  from  that  of  the  Crustacea  and  other  Articulata  in  not 
being  of  a  chitinous  nature ;  and  this  hj^othesis  was  used  in  arguments 
relative  to  the  affinities  of  the  Rotatoria.  Thus  Kaufmann  advances  it  as  a 
decided  distinction  between  this  class  and  the  TardigTada ;  but,  as  Leydig 
remarks,  the  skin  of  the  latter  animals  is  even  more  affected  by  potash  than 
that  of  the  Rotifera  {see  section  on  the  Affinities  of  Rotatoria). 

The  cuticle,  as  just  intimated,  differs  much  in  firmness  and  thickness  in 
different  species.  It  is  softest  in  those  which  live  in  an  external  case — e.  g. 
Stephanoceros,  Melicerta,  Tuhicolaria, — and  in  such  as  are  invested  by  a 
gelatinous  sheath — e.  g.  Notomyyiata  centrura.  In  Diglena,  Notommata  aurita 
(XXXVI.  3,  4),  Asplanchna,  and  others,  it  is  firmer,  but  still  flexible ; 
whilst  in  such  genera  as  Bracliionus  (XXXIX.  16,  17,  21),  Noteus,  Salpina, 
and  Euchlanis  (XXXIX.  4)  it  attains  a  rigid,  horny  consistence,  resembHng 
that  of  the  shells  of  Entomostraca.  Even  where  the  skin  is  of  considerable 
firmness,  it  is  yet  capable  of  distension,  as  Perty  observed  in  the  Scaridium 
longicaudum  when  its  stomach  was  stretched  with  food.  The  form  of  the 
body  is  much  modified  by  the  degree  of  firmness  of  the  integument.  When 
this  is  soft  and  yielding,  or  flexible,  the  figure  is  rounded,  and  more  or  less 
elongated,  and  may  taper  towards  one  or  both  extremities ;  but  when  the 
cuticle  is  much  hardened,  the  rounded  configuration  is  often  lost,  and  various 
irregularities  in  form  result.  For  example,  in  Metopidia  and  in  Euchlanis 
dilatata  (XXXVIII.  5)  the  body  is  ovate  and  compressed,  or  depressed ;  in 
Emhlanis  triquetra  it  is  triangular  (XXXIV.  443)  ;  in  E.  hipposideros  and  in 
Lepadella  (XXXIV.  430-432)  the  dorsum  is  convex,  the  abdominal  surface 
flat ;  in  Noteus  quadricornis  (XXXVIII.  25-27),  suborbicular  and  com- 
pressed ;  in  Mastigocerca  carinata  and  Ratulus  carinatus  (XXXIV.  438-440) 
it  is  prismatic,  with  one  angular  ridge  or  crest ;  in  Colurus,  compressed 
laterally. 

There  is,  besides,  a  direct  relation  between  the  segmentation  of  the  integu- 
ment, the  perfection  of  its  articulate  condition,  and  the  degree  of  firmness  of 
the  integument.  The  soft- skinned  Rotatoria  only  throw  their  bodies  into 
folds  during  contraction,  whilst  those  with  firmer  cuticle,  such  as  Philodincea, 
develope  the  sliding  joints,  and,  lastly,  those  {e.  g.  Lepadella  and  Euchlanis) 
which  have  a  dense  homy  covering  present  two  or  three  decided  segments, 
recalling  in  form  and  disposition  the  di^dsions  of  the  external  skeleton  of  the 
monocular  Entomostraca,  or  even  of  the  higher  Crustacea. 

Where  the  cuticle  is  condensed  into  a  rigid,  horny  lamina,  defending  the 
animal  like  the  shell  of  a  Crustacean  or  the  carapace  of  a  tortoise,  it  may 
well  be  termed  a  testa,  testula,  or  lorica.     This  last  name  was  very  loosely 


OF  THE  ROTATOEIA.  395 

used  by  Ehrenberg,  being  alike  applied  to  the  soft,  pliant  skin,  to  the  hard 
shell-liie  cuticle,  and  to  the  loose  and  large  external  cases  in  which  some 
Botatoria  live,  as  do  the  Coralline  Polypes,  in  a  cell  or  chamber.  If  limited, 
however,  in  its  signification,  as  above  suggested,  the  term  may  still  be  use- 
fully retained,  and  is  preferable  to  the  word  '  shell,'  which  peculiarly  belongs 
to  the  habitation  of  the  Mollusca.  By  some  authors  the  term  carapace  is 
emiDloyed ;  but  to  this  there  occurs  a  similar  objection. 

The  lorica  received  from  Ehrenberg  various  names,  according  to  its  form. 
Where  a  firm  cuticle  entirely  enveloped  the  trunk,  lea\dng  the  head  and  tail 
free,  it  constituted  a  testula,  as  in  Pterodina ;  where  it  covered  only  the  upper 
surface  and  sides,  it  formed  a  scutellum  or  shield,  as  in  Monura  (XXXTV. 
457-459).  The  term  '  carapace,'  employed  by  some  authors,  is  equivalent 
to  scutellum.  The  anterior  and  posterior  openings  of  a  testule  vary  much  in 
different  species ;  and  an  equal  diversity  occui's  in  the  space  left  uncovered 
by  a  scutellum.  This  space  is  small  and  very  narrow  in  Euclilanis  Lynceus, 
in  E.pyi-iformis,  and  in  E.  dejiexa.  In  the  last,  moreover,  the  free  edges  are 
bent  outwards  at  right  angles.  In  several  genera,  again,  the  lorica  appears 
composed  of  an  upper  and  an  under  plate,  or  is,  in  other  words,  bivalved. 
This  is  seen  in  Dinocharis  (XXXIV.  454,  455),  Salpina,  and  Colurus,  and 
resembles  the  envelope  in  some  of  the  lower  Crustacea,  as  Cypris.  In  a  few 
Rotifera,  e.  g.  Euchlanis  (XXXYIII.  5),  the  lorica  aj)pears  much  too  large, 
the  contained  viscera  only  partially  filling  it.  An  increased  firmness  of  the 
lorica  enables  it  to  resist  decomposition  longer  than  its  soft  contents ;  hence 
the  occurrence  of  empty  ones.  Where  the  integument  is  of  sufficient  firmness 
to  present  an  anterior  and  posterior  margin,  it  is  subject  to  many  variations 
in  form.  Thus  it  may  be  truncate  in  front,  as  in  Hydatina,  Dlglena 
(XXXIII.  403-405),  and  Polyartlira  (XXXVIII.  30) ;  or  behind,  as  in 
Notommata  Felis.  It  is  crescentic  in  Metopidia ;  deeply  and  widely  notched 
in  Lepadella  patella ;  has  several  spines,  in  front  only,  in  Anura^a  ;  and  both 
anteriorly  and  posteriorly  in  Noteus,  Salpina  (XXXIY.  447-453),  and  Bra- 
chionus  (XXXIY.  499-501).  Sometimes  the  spines  are  so  short  and  vdde, 
that  the  border  appears  simply  dentated  or  undulated  ;  in  other  cases,  spines 
may  be  long  and  strong,  and  themselves  dentated,  as  in  Noteus  quadricornis 
(XXXYIII.  25).  Not  only  do  the  anterior  and  posterior  margins  differ,  but 
even  those  of  the  upper  and  under  surface  of  the  lorica,  for  example,  in 
Salpina  spinigera  and  in  S.  mucronata.  Animals  with  spines  projecting  from 
the  anterior  margin,  Ehrenberg  speaks  of  as  '^  homed.' 

The  surface  of  the  integument  is  variously  modified.  Ths  slightest  change 
from  the  normal  smooth  condition  consists  in  a  shagreened,  dotted,  or  stippled 
surface,  or  in  the  presence  of  fine  lines, — e.  g.  in  Amurea  inermis,  Dinocharis 
and  Diglena  lacustris.  In  Notommata  centrura,  fine  silky  prominences  clothe 
the  surface.  In  Noteus  quadricornis  and  Brachionus  militaris,  the  points  are 
elevated,  and  give  the  surface  a  rough  (scabrous)  aspect.  Lines  crossing  each 
other,  producing  a  tessellated  or  reticulated  condition,  are  seen  in  Anm^cea 
curvicornis  and  in  Brachionus  BaTceri ;  whilst  in  Anuixea  testudo,  Brachionus 
militaris  (XXXIX.  21,  22),  and  Noteus  quadricornis  (XXXYIII.  25)  the 
lines  assume  the  character  of  ridges,  and  divide  the  surface  into  squares  or 
facettes.  Radiating  or  curved  strise  are  seen  in  Anuroea  striata  and  A. 
foliacea,  which  in  Euchlanis  Lynceus  are  replaced  by  flutings. 

The  elevated  points  may  assume  a  further  development,  and  project  fi'om 
the  surface  in  the  form  of  ciu'ved  spines  or  hooks  (acidei),  as  in  Philodina 
aculeata ;  or  they  may  be  so  extended  in  length  as  to  form  long  spines  or 
rigid  styles  or  setae  having  particular  functions,  as  in  Triarthra  (XXXYIII. 
30,  31,  32),  and  Polyarthra,  where  they  are  important  organs  of  locomotion. 


396  GENERAL  HISTORY  OF  THE  INFUSORIA. 

In  the  last-named  genus  they  attain  a  still  more  complex  natiu-e,  and  assume 
a  plumose  (feather-like)  structui^e  (XXXYIII.  30). 

The  opposite  condition  is  seen  in  depressions  or  pits,  few  and  scattered,  on 
the  surface  of  the  integument,  often  apparently  surroimded  by  a  margin. 
Illustrations  are  found  on  the  dorsum  of  Polyarthra,  of  Notommata  Myrmeleo, 
and  of  N.  Sieboldii  (XXXYII.  32). 

All  the  markings  and  processes  of  the  integument  of  Rotatoria  are  produc- 
tions of  the  chitinous  cuticle,  just  as  hairs,  feathers,  horns,  and  claws  in  the 
Yertebrata  originate  from  the  epidermis.  They  are  similarly  affected  by 
chemical  reagents,  and  decompose  mth  the  same  facility  as  the  integument 
which  supports  them.  They  are,  moreover,  of  much  value  in  supplying 
generic  and  specific  characters. 

Several  genera  possess,  in  addition  to  the  integument  immediately  investing 
them,  an  external  sheath  oi'  case,  to  the  bottom  of  which  they  are  attached 
by  a  prolongation  of  the  body  in  the  form  of  a  contractile  pedicle.  This 
external  sheath  received  from  Ehrenberg  the  particular  designation  of 
'  urceolus ; '  and  consequently  the  beings  inhabiting  it  were  said  to  be  uix-eo- 
lated,  or,  as  many  prefer  to  say,  are  '  encased.'  The  composition  of  the  case 
varies  greatly  ;  for,  although  it  originates  always  as  a  secretion  from  the 
animal  itseK,  the  substance  differs  in  different  genera,  both  in  its  characters 
and  modes  of  formation :  moreover,  in  some  species,  particles  of  foreign 
matters  are  superadded,  to  give  it  strength  and  solidity. 

The  cases  of  Floscularia  (woodcut,  Part  II.)  and  Stephanoceros  (XXXYII. 
1)  are  coloui4ess,  and  apparently  structureless,  and,  though  roomy,  are  visible 
with  difficulty  on  account  of  their  tenuity  and  transparency.  They  are  best 
demonstrated  by  the  addition  of  some  colouiing  matter,  such  as  indigo,  to 
the  water  in  which  they  are  examined.  An  exception  to  the  usually  trans- 
parent homogeneous  case  of  Floscularia  occurs,  according  to  Dr.  Dobie,  in  F. 
campanulata.  Dujardin,  again,  asserts  that  the  uixeolus  of  Flosculana  may 
vanish  dming  the  lifetime  of  the  animal,  and  that  in  many  French  species 
it  is  always  absent ;  he  therefore  denies  its  value  in  generic  distinctions. 
His  statements,  however,  require  confirmation,  being  opposed  to  the  observa- 
tions of  other  naturalists. 

Again,  the  tubes  of  CEcistes,  ConocJiilus,  and  Lacinularia  are  hyaline,  with 
a  more  gelatinous  consistence,  and,  in  the  two  last  genera,  adhere  together. 
In  ConocMlus  the  individuals  are  aggregated  around  a  central  globule  of 
gelatine,  from  which  they  project  like  so  many  rays ;  whilst  in  CEcistes  each 
luxeolus  is  free,  but  has  its  surface  encrusted  mth  foreign  particles.  Tuhi- 
colaria  (XXXII.  379)  has  a  thick  gelatinous  case,  of  a  milky  hue,  which, 
from  its  effervescing  on  the  addition  of  an  acid,  is  attributed  to  a  deposit  of 
carbonate  of  lime  within  it.  In  young  animals  the  case  is  quite  transparent. 
This  is  also  true  of  the  urceolus  of  Limnias  (XXXYI.  2),  which,  as  it  grows 
older,  changes  to  a  brown  and  brownish-black  colour;  and,  as  it  is  viscid, 
various  extraneous  bodies  affix  themselves  to  it.  In  one  newly- discovered 
species,  the  usually  smooth  surface  is  departed  from,  and  the  case  becomes 
annulated,  and  is  also  semitransparent.  Dr.  Bailey  found  in  North  America 
a  species  of  Melicerta  mth  a  brown  annulated  urceolus.  But  the  most  re- 
markable tubular  sheath  is  that  of  Melicerta  ringens  (XXXII.  386 ;  XXXYI. 
1),  which  is  composed  of  equal-sized  lenticular  peUets,  of  a  brownish- red 
colour,  and  of  a  substance  secreted  by  the  animal  itself  and  deposited  in  a 
regular  oblique  or  spiral  series.  This  wonderful  phenomenon  wiU  be  consi- 
dered hereafter,  in  the  section  on  Secretion.  The  cohesion  of  particles  of 
foreign  substances  to  the  enclosing  tubes  is  seen  also  in  some  Annelida,  and 
in  the  aquatic  larvae  of  certain  Insects. 


OF  THE  KOTATOEIA.  397 

The  m'ceolus  serves  as  a  place  of  shelter  and  defence  for  the  adult  animal, 
and  also  for  the  ova  it  deposits.  The  latter  often  remain  within  the  case 
until  they  are  hatched.  The  necessity  for  shelter  is  entailed  by  the  fixed 
condition  of  these  Rotatoria,  because,  unlike  the  free  animals,  they  cannot 
escape  their  pursuers  by  flight.  By  means,  therefore,  of  their  highly  con- 
tractile pedicles  they  can  entLrely  withdi-aw  themselves  within  theii'  tubular 
dweUing,  until  the  threatening  danger  is  overpast.  Ehrenberg,  however, 
states  that  the  animal  may  detach  itself  from  its  case  and  svdm  away  free  : 
if  this  be  true,  we  must  suppose  it  will  again  affix  itself  and  proceed  to  con- 
struct another  urceolus.  The  possibility  of  this  acquisition  of  fi-eedom  is 
favoured  by  the  analogous  detachment  of  Vorticellce,  and  the  formation  by 
them  of  a  new  pedicle  on  reattaching  themselves.  Empty  ureeoli  are  indeed 
not  uncommon  ;  but,  unless  the  process  be  witnessed,  it  is  impossible  to  say 
whether  the  inhabitant  has  quitted  its  abode  at  will,  or  disappeared  by  de- 
composition after  death  or  by  becoming  a  prey  to  other  animals.  Mr.  Gosse 
noticed  that  a  Melicerta,  which  had  its  case  slit  up  for  some  distance,  pro- 
truded itself  through  the  opening ;  and  during  several  days'  observation, 
though  it  made  pellets,  they  were  never  deposited  in  order  to  repair  the 
breach,  but  were  allowed  to  float  away :  this  observation  does  not  support 
Ehi-enberg's  above-cited  opinion.  Each  member  of  a  colony  of  adherent 
Rotatoria  is  generated  free,  and  swims  at  large  until  it  chooses  to  join  its 
.fellows  in  becoming  fixecl.  The  encased  Rotatoria  attach  themselves  to  any 
convenient  substance  in  the  water,  especially  the  stems  and  leaves  of  water- 
plants.  The  single  individuals  are  many  of  them  just  visible  to  the  naked 
eye  ;  and  where  they  unite  in  compound  masses,  they  can  be  detached  in  the 
form  of  jelly-like  globules,  having  a  nulky  hue,  often  -1-th  of  an  inch  and 
upwards  in  diameter.  Tubes  of  Melicerta  and  Tubicolaria  occur  from  -j^^th  to 
^th  of  an  inch  in  length. 

An  external  envelope  is  found  ia  a  few  free  Rotatoria  in  the  form  of  a  soft 
gelatinous  coating, — for  example,  in  Notommata  Copeiis  and  JV.  centrura 
(XXXYIII.  26).  In  the  latter  species,  moreover,  this  coat  exhibits  a  regular 
arrangement  of  fine  molecules  within  it,  and  a  consequent  apparent  striation. 
Ehi'enberg  describes  the  confervoid  fibres  of  Hygrocrocis  as  sometimes  para- 
sitic on  tliis  gelatinous  involucre ;  but  this  account  Leydig  doubts.  It  is 
certainly,  however,  not  improbable,  since  ureeoli  of  every  variety  furnish  a 
favourable  nidus  to  parasites,  both  vegetable  and  animal;  and  this  writer 
himself  speaks  of  Yibrios  adherent  to  the  hyaline  case  of  Stejphanoceros,  on 
the  surface  of  which,  as  he  imagines,  they  sometimes  give  rise  to  an  ap- 
parent striation. 

Appejtdages  of  Rotatoeia. — Each  great  division  of  the  body  is  furnished 
with  certain  prominent  parts  or  appendages,  adapted  to  supj^ly  various  re- 
quirements of  the  economy.  The  appendages  of  the  head  and  neck  exceed 
all  others,  both  in  number  and  importance, — the  rotary  organ,  the  pecidiar 
characteristic  of  the  class,  being  one  of  them. 

This  latter  organ  is  essentially  a  ciliated  wreath  or  circlet,  mostly  sup- 
ported on  an  expanded  margin  or  disk,  and  subject  to  considerable  variations, 
which  are  employed  in  the  classification  of  these  animals ;  the  rotary  is  also 
called  the  rotatory  organ  or  disk,  the  trochal  disk,  at  times,  less  definitely, 
the  ciliated  disk  or  wreath,  or  the  wheel  organ. 

Ehrenberg  employed  the  rotaiy  organ  in  its  different  modifications  as  the 
basis  of  his  classification  of  the  Rotatoria,  making  two  chief  types,  in  one  of 
which  the  ciliated  ring  was  single  and  complete,  in  the  other  subdivided  into 
several  independent  portions  or  secondaiy  wheels.  A  subordinate  type  pre- 
sented two  equal  symmetrical  circlets  of  cilia,  forming  a  pair  of  wheels.     To 


398  GENERAL  HISTOET  OF  THE  INFIJSOEIA. 

the  first  of  these  groups  he  gave  the  name  of  Sorotivcha,  to  the  second  Poly- 
troclia,  and  to  the  last  Zygotrocha.  The  further  subdi\dsions  which  he  formed, 
and  the  names  he  applied  to  the  varieties  of  the  rotary  organ,  will  be  ex- 
plained in  the  section  on  Classification.  The  belief  in  actually  compound 
trochal  disks  has  been  shared  by  nearly  all  observers,  and  both  Perty  and 
Siebold  adopt  it  along  with  Ehrenberg's  classification.  On  the  other  hand, 
it  is  denied  by  Leydig,  who  affirms  that  the  disk  is  never  divided  into 
such  secondary  wreaths  or  lobes,  but  always  constitutes  one  continuous 
margin,  variously  extended  and  folded,  and,  it  may  be,  furnished  with  inde- 
pendent accessory  ciliated  disks.  This  able  writer  remarks — "  It  is  only  to 
the  exceptional  genera  StepJianoceros  and  Floscularia,  that  Ehrenberg's  term 
Polytrocha  can  be  rightly  applied.  In  truth,  an  observation  recorded  by  the 
great  micrographer  himself  negatives  his  hypothesis  of  polytrochous  division, 
that,  viz.,  where  he  applied  strj^chnia  to  the  rotary  organ  of  Hydatina,  which 
became  thereby  reduced  to  a  simple  whorl  of  cilia." 

The  various  degrees  of  complication  assumed  by  the  trochal  disk  are  thus 
detailed  by  Leydig : — "  It  forms  a  simple  ciliated  margin  around  the  mouth 
of  Notommata  tardigrada ;  in  Stephanops  (XL.  8,  10)  it  is  wider,  more  pro- 
minent, and  triangular ;  in  Euchlanidota,  Polyarthra  (XXXVIII.  30),  Di- 
glena,  Distemma,  Hydatina  (XL.  1),  Pleurotrocha,  and  others,  it  occupies  the 
entire  periphery  of  the  head,  and  is  not  at  all,  or  but  very  slightly,  elevated 
as  a  distinct  disk  above  it ;  in  Notommata  Copeus,  N.  aurita  (XXXVI.  4), 
and  in  SyncJiceta,  it  is  enlarged  and  elevated  as  a  distinct  disk  on  each  side  of 
the  head,  forming  the  "  ears  "  so  called  by  Ehrenberg ;  in  other  instances  it 
is  enlarged,  and  projects  on  the  ventral  sui'face  of  the  animal  like  a  ciliated 
trunk  or  proboscis.  A  higher  development  is  seen  in  Brachionns  (XXXIX. 
15-18)  and  Philodina,  where  the  ciliated  border  is  involuted  and  extended 
upwards  laterally  (XXXVIII.  2)  ;  and  lastly,  in  Megalotrocha,  Lacinularia, 
Melicerta  (XXXVI.  1 ;  XXXVII.  17),  and  Limnias  (XXXVI.  2),  the  high- 
est complexity  is  reached,  and  the  trochal  disk  appears  to  be  an  appendage 
surmounting  the  head,  expanded  in  the  form  of  a  sinuous  or  lobed  ciliated 
margin."  In  the  variety  last  mentioned,  Mr.  Gosse  speaks  of  the  expanded 
lobes  under  the  name  of  "  petals." 

The  row  of  cilia  flinging  the  rotary  organ  is  often  single,  but  in  several 
species  is  double,  and  even  treble.  Mr.  Huxley  has  noticed  its  double  con- 
dition in  Lacimdaria  sociaJis.  To  quote  his  description — "  The  edge  of  the 
disk  has  a  considerable  thickness,  and  presents  two  always  distinct  margins, 
an  upper  and  a  lower,  of  which  the  former  is  the  thicker,  and  extends  beyond 
the  latter.  The  large  cilia  are  entirely  confined  to  the  upper  margin,  and 
form  a  continuous  horse-shoe-shaped  band,  which,  upon  the  oral  side,  passes 
entirely  above  the  mouth.  The  lower  margin  is  smaller  and  less  defined  than 
the  upper ;  its  cilia  are  fine  and  small,  not  more  than  one -fourth  the  size  of 
those  of  the  upper  margin.  On  the  oral  side  this  lower  band  of  ciha  fonns 
a  V-shaped  loop,  which  constitutes  the  lower  and  lateral  margins  of  the  oral 
aperture.  About  the  middle  of  this  margin,  on  each  side,  there  is  a  small 
prominence,  from  which  a  lateral  ciliated  arch  runs  upwards  into  the  buccal 
cavity,  and,  below,  becomes  lost  in  the  ciha  of  the  pharynx.  The  aperture 
of  the  mouth,  therefore,  lies  between  the  upper  and  lower  ciliated  bands 
(XXXVIII.  21)." 

Prof.  Williamson  has  signahzed  a  like  arrangement  in  Melicerta  (XXXVII. 
17),  and  LeycHig  in.  Br achionus,  Pterodina  (XXXVIII.  29),  and  Megalotroch<xa. 
The  latter  writes — "  On  the  free  surface  of  the  head  oi  Brachionus  (XXXVIII. 
14,  15),  two  lateral  and  and  a  median  lobe  elevate  themselves,  which  Huxley 
compares  to  the  two  ciliated  borders  of  Lacinularia, — an  interpretation  that 


OF  THE  KOTATORTA.  399 

has  very  many  arguments  in  its  favour,  and  in  support  of  which  I  may 
adduce  the  structure  of  the  rotaiy  organ  of  Pterodina.  This  species,  belong- 
ing to  the  family  of  BracMoncea,  has  its  free  projecting  lobes  furnished  with 
a  double  row  of  cilia,  analogous  to  what  occurs  in  Megalotrocha.  That  the 
wheel  organ  of  Philodincea  also  is  referrible  to  the  same  type,  is  evident 
from  the  account  Huxley  gives  of  it." 

Cohn  {Zeitschr.  1855,  vii.  p.  437)  describes  two  complete  rows  of  cilia, 
besides  five  or  six  special  ciliary  bundles,  on  the  head  of  Hydatina  senta 
(XL.  1).  On  the  outer  margin  is  an  unbroken  row  of  long  and  fine  cilia, 
extending  thence  into  the  oral  fissiu"e,  and  still  further,  into  the  oesophagus. 
Within  this  circle  is  an  interrupted  one  formed  by  6  or  7  (Ehrenberg  counted 
11)  bundles,  having  few  or  many  broader  and  longer  cilia,  nearly  resembling 
the  setae  on  Stylonychia,  and  supported  on  as  many  cushion-like  eminences. 
Lastly,  the  thii^d  series  is  unbroken  like  the  first,  and  composed  of  finer  cilia, 
disposed  in  a  quincimcial  manner  in  two  lines.  All  the  parts  of  this  ciliary 
apparatus  work  harmoniously  together  in  eftecting  the  movements  of  the 
animal  or  in  securing  the  capture  of  food. 

The  figure  of  the  trochal  disk  (XXXYIII.  14,  15,  20,  21)  varies  exceed- 
ingly, as  the  quotation  from  Leydig  indicates,  and  is  especially  influenced  by 
the  addition  of  supplementary  ciliated  eminences.  In  Megalotrocha  (XXXII. 
374-378)  the  disk  is  horse-shoe-shaped ;  in  Melicerta  it  is  petaloid,  or,  as 
Prof.  Williamson  called  it,  flahelliform  ;  in  Rotifer  it  is  seen  under  two  forms, 
according  to  its  degree  of  expansion,  either  as  a  single  conical  eminence,  or, 
when  completely  unfolded,  as  two  cylinder-like  processes,  one  on  each  side 
of  the  head,  apparently  whorling  like  two  wheels.  In  the  family  Brachio- 
ncea  (Ehr.)  accessory  disks  or  processes  give  rise  to  much  complication 
(XXXIX.  15-22).  Ehrenberg  described  this  family  as  having  two  ciliated 
organs — a  central  one  of  three  parts,  and  a  lateral  one  of  two, — the  latter 
being  the  time  wheel  organ,  and  the  former,  frontal  processes  which  are  stiffly 
extended  whilst  the  rotary  organ  is  in  action.  An  appendage  such  as  that 
last  named,  in  Koteus,  he  designates  a  three-lobed  ciliated  brow. 

Exceptional  or  aberrant  forms  of  the  cihated  disk  are  seen  in  Floscidaria, 
in  Steplumoceros,  and  in  Lindia  (XXXIX.  1,  3).  In  the  first,  the  head 
(XXXYII.  1)  is  surmounted  by  five  ciliated  flattened  lobes,  ending  in  knob- 
like processes  which  bear  very  long,  divergent,  non-vibratile  haii^s  or  cilia 
of  uniform  thickness  {see  woodcut,  Part  II.).  "  These  exceptional  cilia,"  says 
Dr.  Dobie,  ''  are  slowly  moved  and  spread  out  by  the  contractile  substance 
of  the  lobes  of  the  rotary  organ."  In  Steplianoceros,  the  departure  from  the 
normal  structure  is  still  greater  (XXXYII.  1), — so  much  so,  that  the 
ciliated  appendages  have  no  claim  to  the  title  of  a  rotary  organ.  Five  long 
arms  extend  from  the  head,  Kke  five  tentacles,  covered  by  cilia  in  rings  (ver- 
ticellate  ciHa).  These  arms  not  only  act  like  a  common  trochal  disk  by  pro- 
ducing a  vortex  directing  aU  particles  within  its  range  to  the  mouth,  but  also 
as  organs  of  prehension,  closing  themselves  on  any  larger  object  which  may 
come  within  their  grasp.  This  ciliated  armature  around  the  head  bears  a 
close  resemblance  to  that  of  the  cilio-brachiate  Polypes  or  Bryozoa,  to  which 
class  of  animals,  indeed,  several  distinguished  naturalists  have  referred  the 
genus  Stephanoceros,  not  merely  on  account  of  this  one  affinity  named,  but 
also  from  several  other  coincident  characters.  A  third  peculiar  form  of  rotary 
organ  has  been  recently  pointed  out  by  Cohn  in  Lindia  {Zeitschr.  1858,  p. 
284).  It  takes  the  form  of  a  club-shaped  process  on  either  side  of  the  head 
(XXXIX.  1,  3),  having  its  extremity  somewhat  expanded  and  spherical. 
Cilia  exist  only  on  the  round  summits  of  these  processes  ;  there  is  no  whorl 
around  the  margin  of  the  head,  none  elsewhere  on  the  body  ;  and  this  ex- 


400  GENERAL  HISTORY  OF  THE  INFUSORIA. 

ample  may  be  adduced  as  that  of  the  least  complicated  rotary  organ  among 
Rotifera. 

It  is  in  these  aberrant  forms  alone  that  the  ciliated  apparatus  can  be  strictly 
called  " polytrochous  f  in  them,  also,  the  wheel-like  motion  is  completely 
absent.  This  peculiar  motion,  on  the  contrary,  is  most  e\ident  where  the 
wreath  is  a  simple  circle,  as  in  Conochilus  and  Actinurus,  or  where,  as  in 
Rotifer  and  Philodina,  it  is  peculiarly  involuted,  although  continuous.  Where, 
on  the  contrary,  it  is  interrupted  by  a  notch  at  any  point,  or  is  sinuated,  or 
complicated  by  supplementary  processes,  as  in  Hydatina  (XL.  1),  Diglenaj 
many  Notommata  (XXXVII.  29,  32),  Synchceta,  &c.,  the  illusion  of  com- 
plete revolutions  vanishes. 

Formerly,  the  belief  existed  that  an  actual  whiiiing  of  the  ciliated  cephahc 
appendages  took  place,  and  that  the  little  animals  moved  along,  by  the  aid  of 
these  wheels,  after  the  manner  of  a  steamer  with  its  paddle-wheels.  Such 
an  opinion  is  no  longer  entertained ;  and  various  explanations  of  the  apparent 
rotary  motion  are  now  offered  in  its  stead.  Dutrochet  attributed  it  to  the 
undulation  of  a  delicate  membrane  fi^inging  the  head  of  the  Rotatoria. 
Faraday  explains  it  by  supposing  the  distinct  cilia  to  become  visible  by 
slowly  returning  to  an  erect  state,  after  having  previously  been  suddenly 
bent.  Ehrenberg  assumed  the  existence  of  four  muscles  at  the  base  of 
each  eilium, — each  muscle  acting  in  its  own  dii'eetion,  and  so  producing  a 
revolution  around  the  fixed  point  of  attachment  or  base  of  the  eilium.  In 
this  way,  each  eilium  would  be  alternately  nearer  to  or  more  remote  from 
the  eye,  and  more  or  less  visible. 

Another  explanation  has  been  offered  by  Dujardin.  He  says — *'  The  vibra- 
tile  cilia  being  arranged  parallel  and  at  equal  distances,  will  equally  refi-act  or 
intercept  the  light,  and  none  will  be  more  visible  than  the  rest ;  but  if,  by  a 
movement  propagated  along  the  row  of  ciha,  some,  momentarily  inclined,  are 
brought  into  juxtaposition  with  adjoining  ciUa,  the  light  will  be  more  inter- 
cepted, and  a  band  more  or  less  dark  will  be  the  result.  It  can  be  imagined, 
therefore,  that  if  the  cilia  come  to  be  inclined  one  after  another,  a  series  of 
juxtapositions,  or  of  apparent  intersections  will  be  produced  in  the  direction 
of  the  general  movement.  Further,  if  each  of  the  intersections  preserve  the 
same  form,  as  if  produced  by  a  number  of  equal  lines,  and  are  equally  in- 
clined to  each  other,  an  appearance  of  a  solid  body  of  a  definite  foim,  like  the 
teeth  of  a  saw  or  the  spokes  of  a  wheel,  moving  uniformly,  presents  itself  to 
the  eye." 

The  action  of  the  trochal  disk  is  under  the  control  of  the  animal.  The 
cihary  movement  can  be  arrested  at  will  or  exercised  ^ith  varying  rapidity ; 
or  the  whole  organ  may  be  retracted,  partially  or  entirely,  within  the  body. 
When  completely  withdrawn,  the  ciliary  wreath  can  frequently  be  detected 
at  the  fore  part  of  the  animal,  oftentimes  deep  within  the  trunk,  and  gene- 
rally in  the  form  of  a  striated  cyhnder  at  the  bottom  of  a  funnel-like  canal. 
In  complete  retraction  the  anterior  extremity  of  the  body  is  involuted,  or 
doubled  inwards,  and  supports,  as  it  were,  the  ciliated  wreath  within,  whilst 
the  contractility  of  the  integument  at  the  margin  closes  the  entrance  pretty 
accurately,  giving  a  more  or  less  conical  outline  to  the  fore  part  of  the  ani- 
mal (XXXYII.  19 ;  XXXIX.  17).  In  complete  retraction  of  the  trochal 
disk,  the  antenna-like  processes  which  may  be  seated  on  it  are  also  with- 
drawn ;  but  at  other  times,  when  the  inversion  is  incomplete,  these  processes 
continue  to  project  from  the  head,  and  in  the  process  of  evolution  are  always 
the  first  to  appear,  as  if  intended  to  test  the  safety  of  unfolding  the  delicate 
ciliary  wreath. 

The  inversion  of  the  ciliary  apparatus  and  appendages  is  effected  by  strong 


OF  THE  ROTATOEIA,  401 

muscles  arising  within  the  abdomen,  which  draw  do^Tiwards,  and  therefore 
inwards,  the  disk  to  which  they  are  attached.  At  the  commencement  of 
their  traction,  they  draw  together  the  sides  of  the  ciliary  Avhorl,  then  pull 
inwards  the  cilia,  which  are  previously  collected  in  a  cylinchical  manner,  and 
at  last  cause  the  inversion  of  the  integument  immediately  beneath  the  disk, 
when  the  now  anterior  extremity  of  the  body  contracts  itself  upon  the  in- 
cluded parts.  This  process  of  involution  may  be  arrested  by  the  animal  at 
any  stage  ;  thus,  sometimes  it  is  stayed  when  the  cilia  are  grouped  together 
in  a  cylinder-like  heap,  and  still  project  from  the  head  like  a  pencil ;  or, 
as  above  mentioned,  the  cilia  may  be  withdi-awn,  and  some  process  or  an- 
tenna be  left  protruding.  The  collection  of  the  cilia  into  a  brush-hke  group 
during  the  process  of  retraction  is  well  exemplified  in  the  long  cilia  of  Flos- 
cularia  ;  and  in  Rotifer  and  PliUodina  we  have  a  special  example  of  the  pro- 
trusion of  a  ciliated  process  during  the  involution  of  the  major  part  of  the 
trochal  disk  (XXXYIII.  1).  In  the  genera  last  cited,  this  median  process 
serves  as  the  anterior  organ  of  progression  when  the  animals  advance  in  a 
leech- like  manner,  and  disappears  when  the  paii'  of  trochal  organs  are 
evolved  and  the  crawling  movement  is  changed  to  swimming. 

The  retraction  of  the  trochal  disk  we  may  suppose  to  be  controlled  by  the 
will  of  the  animal  to  arrest  its  motion  or  to  avoid  danger.  Another  motive 
is  conceivable,  especially  in  the  case  of  the  attached  species  :  for  the  ciha, 
when  in  active  operation,  attract  every  sort  of  particle  within  their  vortex — 
as  well  those  appropriate  to  nutrition  as  others  noxious  or  which  have 
been  lately  discharged  and  still  float  about  the  animal ;  hence  it  may  be  ne- 
cessary to  arrest  their  action,  withdraw  the  disk,  and  close  all  access  to  the 
interior,  until  these  unfit  substances  are  floated  away  and  have  been  replaced 
by  others. 

The  ciliated  mechanism  of  the  head  is,  as  just  hinted,  the  active  agent  in 
procuring  food,  by  di^agging  within  its  vortex  the  nutritive  particles  in  reach, 
and  transferring  them  to  the  mouth,  which  is  so  situated  that  the  current 
produced  sets  directly  into  it.  "Where  the  ciliaiy  wreath  is  double,  as  in 
Melicerta,  ''the  food"  (to  use  Prof.  Williamson's  description)  "  that  reaches 
the  mouth  is  whirled  around  the  wheel- organs  along  the  groove  that  sepa- 
rates the  two  circlets  of  cilia ;  and  since  these  circlets  diverge  near  the 
'  chin '  (or  fifth  ciliary  lobe),  the  mouth  being  located  between  them,  the 
food  is  necessarily  conveyed  directly  to  the  latter  organ.  The  two  sets  of 
marginal  cilia,  by  bending  towards  each  other  whilst  in  motion,  almost  con- 
vert this  groove  into  a  sinus,  especially  in  the  two  large  segments."  But 
besides  locomotion  and  nutrition,  the  rotary  apparatus  must  be  admitted  to 
subserve  the  function  of  respiration,  both  by  its  own  delicate  stnicture,  and 
by  its  action  in  constantly  renewing  the  water  around  the  animal ;  also,  by 
forcing  fluid  within  the  alimentary  canal,  it  may  serve  to  aerate  and  renew, 
by  endosmosis,  the  fluid  in  the  general  cavity  surrounding  the  viscera. 

In  the  fixed  species  of  Rotatoria  the  rotaiy  organ  can  have  no  locomotive 
use,  merely  subserving  the  functions  of  nutrition  and  respiration.  In  addi- 
tion to  the  rotary  organ,  the  head  is  often  beset  with  various  appendages 
in  the  shape  of  stjiiform  and  tubular  processes,  lobes,  disks,  uncini,  and 
spines.  These  are  situated  either  witliin  the  cii'cle  of  the  ciliary  wreath  on 
its  margin,  or  immediately  external  to  it.  Examples  of  tapering,  styliform, 
and  bristle-hke  processes  are  found  in  Notommata  Myrmeleo,  Monocerca  bi~ 
cornis,  in  Si/nchcefa,  Monostyla,  Brachionus,  and  others.  On  the  head  of  Cono- 
cMliis  are  four  stout  wart-like  elevations.  In  Polyarthra  platyptera  two  long 
bristles  project  from  near  the  mouth,  each  bent  on  itself  midway  at  a  right 
angle  (geniculate).     Dujardin  describes,  in  his  genus  CoJurella,  an  uncinate 

2i> 


402  GENEEAL  HISTOfiY  OF  THE  IXFrSORlA. 

retractile  appendage  surmoimting  the  trochal  disk.  In  Brachionns  urceolaris 
(XXXIX.  15, 16),  straight  non-vibratile  cilia  occur  between  the  ciliated  lobes 
of  the  rotary  organ ;  and  in  Polyarthra  there  are  fleshy  tentacular  appendages, 
which  Siebold  suggests  are  antennae  or  feelers.  The  2-4  styHform  processes 
of  Synchceta,  Ehrenberg  supposed  to  possess  prehensile  powers.  In  Cono- 
cJiUiis,  four  processes,  terminated  by  bristles,  project  from  the  ciliary  disk ; 
in  Melkerta  are  two  cuiwed  hooks.  To  some  of  these  appendages,  and  to 
others  about  the  head,  various  fanciful  names  have  been  given,  borrowed 
mostly  from  remote  resemblance  in  appearance,  situation,  or  function  to  parts 
existing  in  the  higher  animals.  For  instance,  on  each  side  of  the  head  of 
Notommata  aurita,  N.  Copeus,  and  Diglena  aurita,  a  lobe  of  the  trochal  disk  is 
more  elevated  or  elongated  than  the  rest,  and  has  received  the  appellation  of 
"ear"  or  "  auriciilar ; "  the  2-4  supplementary  processes  of  the  head  of 
Polyarthra  (XXXYIII.  30  a,  h)  have  been  called  "  horns," — a  name  applied 
to  a  similar  projection  in  other  Rotatoria. 

In  Stephanops  a  prominent  scale-like  process  of  the  head  is  kno-\vn  as  the 
"  hood  "  (XL.  8-10).  Mr.  Gosse  speaks  of  a  projecting  spoon-shaped  lobe 
in  MeVicerta,  covered  with  cilia,  as  the  chin,  which  "Williamson  recognizes  a3 
a  '•'  fifth  lobe  "  of  the  wheel  organ  (XXXYII.  17  c).  The  latter  writer,  again, 
adopts  from  Schiiffer  the  appellation  of  "  lips  "  for  two  hook-like  appendages 
of  the  head  of  Melkerta,  and  fui'ther  describes,  on  each  side  the  oral  aperture, 
two  projecting  "  flattened  lobes,  with  ciliated  margins  continuous  with  those 
of  the  '  chin,'  which  obviously  assist  in  directing  the  food  into  the  iDesophagus." 
Lastly,  Ehrenberg  fi-equently  employs  the  term  "  frontal  region  "  or  forehead, 
to  signify  the  anterior  surface  of  the  head. 

Certain  tubular -looking  processes,  freqiiently  fiunished  with  a  pencil  of 
fine  non-vibratile  cilia  or  bristles  at  the  extremity,  have  gained  particular 
consideration  owing  to  the  functions  assigned  them  by  Ehrenberg  and  others. 
They  protrude  from  the  head  near  the  trochal  disk,  and  more  commonly  from 
the  neck,  as  is  seen  in  Rotifer,  Philodhui  (XXXYIII.  20),  Brachionns 
(XXXYIII.  15 ;  XL.  11),  Actinurus,  in  EucJilanis  Lynceus,  in  MeJicerta 
(XXXYII.  17),  in  Salpina  mv.cronata,  in  Notommata  davulata,  N.  Myrraeleo, 
N.  Sieboldii,  and  other  species.  In  aU  the  above  the  appendage  is  single, 
but  in  TuhicoJaria  and  MeJicerta  (XXXYII.  11  cl)  it  is  double.  In  Calli- 
clina  Ehrenberg  mentions  a  thickly- ciliated  proboscis,  apparently  retractile,  and 
attached  to  the  trochal  disk ;  occasionally,  instead  of  tenninating  by  a  bunch  of 
setae,  these  processes  have  a  horn-like  prolongation,  as  in  Notommata  centrura 
and  N.  Copeus.  The  short  conical  elevations  of  Synchceta  and  Polyarthra 
belong  to  the  same  category  with  the  tubular  variety.  A  long  flabeUiform 
process  occurs  in  connexion  with  one  of  the  ciliary  lobes  of  Floscularia,  which 
is  often  called  a  proboscis,  and  supposed  to  be  tubular.  Ehi-enberg  has  as- 
signed two  different  appellations  to  these  tube-like  appendages.  At  one  time 
he  calls  such  a  process  a  sjmr  {''  calcar  "),  and  imagines  that  it  subserves  the 
generative  process  as  an  intromittent  organ  ;  at  another  he  represents  it  as 
a  respiratory  tube  (siphon),  through  which  water  may  enter  to  act  on  the 
vibratiLe  tags  (gills)  seen  within  the  abdomen.  The  former  view  has  found 
no  supporters,  and  is  entirely  set  aside  by  oiu-  present  knowledge  of  the 
reproductive  act  of  the  Rotatoria  ;  the  latter  has  been  admitted  by  several, 
among  others,  by  Siebold,  although  recent  researches  now  render  it  untena- 
ble, and  demonstrate  the  analogy  of  these  appendages  with  the  feelers  (an- 
tennae and  palpi)  of  Entomostraca  and  other  Crustaceans.  Dujardin  seems 
to  have  been  the  fii'st  to  suggest  the  analogy  mentioned.  Referring  to  these 
processes  and  to  others  less  considerable,  terminated  by  a  bundle  of  stiff  ciha,^ 
he  observes  that  they  recall,  to   some  extent,  the  palpi   and  antennae  ot 


OF  THE  ROTATORIA.  403 

Entomostraca  and  Cypns,  and  that  no  trace  of  the  entrance  or  exit  of  water 
is  perceptible,  even  when  particles  of  colouiing  matter  are  diffused  through 
the  liquid,  calculated  to  indicate  the  slightest  current." 

Since  this  was  written,  Perty,  Gosse,  Williamson,  Huxley,  and  Leydig  in 
particular,  have  minutely  studied  the  point  in  dispute,  and  coincide  with  the 
French  naturalist  as  to  the  non-perforated  character  of  the  organ,  and  its  ho- 
mology with  antennae.  Mr.  Gosse  writes — '^  The  tubes  or  spurs  on  each  side 
of  the  head  (of  Melieei^ta)  below  the  chin  (XXXVII.  17  c?  d)  are  evidently 
consimilar  with  the  antennae  of  Rotifer,  &c.  There  is  a  slender  piston  in 
each,  capable  of  being  retracted,  and  beaiing  at  its  extremity  a  tuft  of  very 
fine,  divergent,  motionless  hairs."  Mr.  Williamson's  account  is  more  detailed ; 
he  calls  them  ''  tentacles,"  and  states  that,  when  fully  protruded,  they  are 
seen  "  to  be  terminated  by  a  brash  of  fijie  divergent  setae  implanted  on  the 
convex  side  of  a  small  deltoid  body  {the  jpiston,  Gosse)  (XXXVII.  12) ;  from 
the  flat  side  of  this  latter  appendage  there  proceeds,  along  the  interior  of  the 
tube,  towards  the  body  of  the  animal,  a  delicate  muscular  band  (XXXVII. 
13,  14),  which,  by  its  contractions,  di^aws  the  deltoid  body  backwards,  thus 
inverting  the  extremity  of  the  tube,  and  forming  a  double  sheath  protecting 
the  setae  (XXXVII.  14).  This  inversion  of  the  tube  was,  we  believe,  first 
noticed  by  Dutrochet.  The  whole  apparatus  is,  as  suggested  by  Schaffer,  very 
similar  to  that  seen  in  the  tentacles  of  the  snail,  and  appears  to  constitute  a 
tactile  rather  than  a  respiratory  organ.  This  is  rendered  more  probable  by 
the  fact  that,  when  the  animal  first  emerges  from  its  tessellated  case,  the  ex- 
tremities of  these  two  tentacles  are  the  fii'st  parts  that  make  their  appear- 
ance (XXXVII.  11  del), — the  two  curved  hooks  being  the  next  (XXXVII. 
17  6).  The  setae  are  usually  half  drawn  into  the  inverted  tentacle ;  but  they 
project  sirfficiently  foi-ward  to  constitute  delicate  organs  of  touch,  supposing 
the  deltoid  body,  into  which  they  are  inserted,  to  be  endowed  with  sensi- 
bility. The  animal  cautiously  protrudes  these  tentacles  before  it  ventures 
to  uiofold  its  rotary  organs,  but  it  does  not  dii^ect  them  in  an  exploratoiy 
manner  from  side  to  side,  as  an  insect  does  its  antennae." 

But  there  are  many  strictly  homologous  processes  with  a  terminal  tuft  of 
setae  which  are  tubular  and  not  retractile,  or  other\\dse  neither  tubular  nor  re- 
tractile, but  horn-like  in  figure,  or  merely  conical.  Examples  occur  in  Notom- 
mata  Myrmeleo  (XXXVIII.  26  h)  and  N.  SieholdH  (XXXVIII.  32  g),  and 
in  the  shorter  conical  elevations  on  the  disk  of  Syncliceta  and  Polyarthra,  and 
in  the  horns  of  the  last-named  genus. 

A  further  departure  from  the  highly- developed  antennae  of  some  Rotatoria 
is  exemplified  in  the  fossae,  pits,  or  apparent  apertures  (XXXVIII.  28-30), 
oftentimes  with  elevated  edges,  containing  a  tuft  of  biistles,  which  are  met 
with  usually  on  the  necks  of  the  animals.  These  fossae,  as  weU  as  the 
retractile  and  non-retractile  antennae  of  all  forms,  Leydig  believes  to  be  in 
immediate  and  special  relation  with  nerves  which  extend  to  the  base  of  the 
brush  of  rigid  ciHa.  The  number  of  such  fossae  varies  in  different  species. 
In^  accordance  with  his  hj^othesis  of  respiration,  Ehrenberg  called  them 
"  ciliated  respiratory  openings."  In  Enteroplea  (XL.  2),  Hydatina  (XL.  1), 
Biglena,  Otoglena,  in  Euchlanis  trlquetra,  and  in  several  NotommatcB,  an 
apparent  aperture  exists  on  the  neck.  More  than  two  are  seen  in  Poly- 
arthra, Notommata  Myrmeleo,  and  in  N.  SieholdH  (XXXAT:II.  29),  arranged 
along  the  back;  and  in  Asplanchna.  BrightwelJii  (Gosse),  Dalrymple  met 
with  two  on  the  back,  which  he  supposed  to  be  and  described  as  lateral 
apertures,  but  which,  Leydig  afiiiTas,  have  the  imbroken  cuticle  lining  them 

Interesting  variations  are  found  in  No  fens,  in  which  Ehrenberg  describes 

2d  2 


404  GENEEAL  HISTORY  OF  THE  INTTJSORIA. 

a  short,  stout,  respiratory  tube,  or,  as  it  actually  is,  a  depression  surmounted 
by  a  very  elevated  margin.  In  Notommata  centrura  (XXXYIII.  26  6),  and 
in  N.  Cojyeus,  a  long  seta  projects  from  a  small  elevation  of  the  cuticle,  on 
each  side  of  the  back,  having  its  extremity  divided  like  a  brush.  The  doubtful 
cihated  depression  conceived  by  Prof.  Huxley  to  be  the  nervous  centre,  belongs, 
in  Leydig's  opinion,  to  the  category  of  tactile  fossae. 

Appendages  of  the  Trunk. — The  account  already  given  of  the  cuticle  and 
lorica  and  their  processes,  leaves  no  special  appendages  of  the  trunk  to  be 
described.  Thus  we  have  spoken  of  the  spines  from  the  anterior  and  posterior 
margins  of  the  lorica;,  of  those  which,  in  a  few  examples,  are  produced  from 
its  surface,  and  of  the  setae  or  cirrhi  which  extend  from  it  in  Anurcea  hiremis, 
in  Notommata  Copeus,  and,  on  a  larger  scale,  in  Triarthra  and  Polyarthra 
(XXXVIII.  30  c). 

The  loseudopodium,  or  false  foot,  may  either  be  accounted  a  production  or 
appendage  of  the  trunk,  or  a  distinct  segment  of  the  body.  Its  dimensions 
and  figure  vary  much  in  different  species ;  and  in  several  it  is  entirely  ab- 
sent. It  attains  the  highest  development  in  Philodincea  (XXXYIII.  1,  2), 
where  it  consists  of  several  progressively  diminishing  segments  united  by 
shding  joints,  like  the  tubes  of  a  telescope,  and  is  analogous  to  the  tails  of 
many  Entomostraca,  e.  g.  the  Cydopidce.  In  this  family,  PhiJodincea,  the  body 
tapers  into  the  pseudopodium  by  a  gradual  lessening  of  the  articulated  seg- 
ments ;  so  that  the  termination  of  the  trunk  proper  and  the  commencement 
of  the  process  have  no  external  indication,  except  what  is  supphed  by  the  anal 
orifice  of  the  alimentary  canal,  which  usually  opens  at  the  base  of  the  tail.  In 
other  families  the  termination  of  the  trunk  is  more  abnipt,  and  the  distinct- 
ness of  the  pseudopodium  as  a  subordinate  segment  or  member  strongly  pro- 
nounced (XXXVIII.  25,  26).  The  high  development  of  the  organ  gradually 
diminishes,  until  the  telescopic-jointed  foot-process  is  degraded  to  the  condi- 
tion of  one  or  two  stifi'  styles,  supported  on  an  enlarged  base  (XXXVIII.  22), 
the  intermediate  stages  being  represented  in  various  species  (XXXVIII.  23, 
24,  25,  31).  In  BracMonus,  Colurus,  Stephanops,  and  Dinocharis  the  foot- 
process,  although  of  three  or  more  telescopic  joints,  is  of  much  smaller 
diameter,  and  depends  like  an  appendage  from  the  trunk,  and  is  a  transition 
between  this  form  and  the  usually  tapering  figiu-e  of  the  PMlodina^a ,  as  seen 
in  Rotifer  macrurns,  the  trunk  of  which  is  abruptly  attenuated  into  a  long 
foot.  A  further  reduction  of  the  many-jointed  telescopic  pseudopodium  to 
one  or  two  joints,  terminated  by  a  single,  double,  or  triple  styliform  or 
pincer  process,  is  exemplified  in  many  Notommatce  (XXXVIII.  26).  in 
Cydoglena,  LepadeUa,  Metopidia,  Salpina,  Diglena,  Eospliora,  Jlydatina 
(XL.  1),  Ratidus,  &c.,  where  the  articulate  structure  is  reduced  to  the 
condition  of  an  appendage  of  the  trunk,  its  terminations  assuming  the  chief 
importance.  Indeed,  in  some  cases,  one  or  two  styliform  processes  seem  to 
be  produced  immediately  fi^om  the  trunk  without  the  intervention  of  an 
articulated  segment  at  the  base  (XXXIX.  1-3).  At  the  same  time  a  styh- 
form  foot-process  is,  as  a  rule,  a  very  short  pseudopodium  supporting  one  or 
more  long  styles.  In  the  case  of  the  less -developed  or  perfect  tail-processes, 
the  section  of  the  body  is  frequently  attached  obliquely  to  the  trunk. 

In  a  very  few  examples  the  posterior  dorsal  surface  of  the  body  is  pro- 
longed as  a  true  tail,  having  the  pseudopodium  fixed  in  front  of  it,  the 
anal  orifice  being  between  them.  This  is  witnessed  in  Notommata  Copeus 
(XXXVIII.  26). 

The  pseudopodium  has  in  some  genera  styliform  processes  attached  to 
it  throughout  its  length,  as  seen  in  the  highly-developed  telescopic  pro- 
longation of  the  PhiJodincea  (XXXVIII.  1),  in  Callidina,  Rotifer,  Actinurus, 


or  THE  KOTATOEIA.  405 

and  Pliilodiyia,  and  also  on  the  shorter  foot-process  of  Dlnocharis.  These 
styles  are  moveable  and  flexible,  and  occur  in  a  single  pair  or  in  two  or  three 
paii's ;  Ehrenberg  gave  to  such,  when  short  and  not  rigid,  the  name  of  '  toes, 
and  distinguished  the  prolongation  on  each  side  of  the  posterior  border  of  the 
shding-joints,  seen  in  Rotifer,  Actinurus,  and  Callid'ma,  as  '  hom-like  pro- 
cesses.' In  Scaridium  (XXXYIII.  22)  and  Dlnocharis,  the  foot,  though 
jointed,  seems  not  to  be  retractile. 

The  pseudopodium  diifers  much  in  its  length  and  mode  of  termination. 
Where  the  articulated  segments  are  few  and  small,  the  foot,  if  terminated  by 
styles,  oftentimes  acquires  a  great  length.  In  some  species  the  terminal 
styles  are  three  in  number — e.  g.  Actinurus,  Philodina  Neptunius,  DinochariSf 
and  in  some  Stephanoijes  ;  and  more  frequently  the  central  style  is  shortest. 
Two  teiminal  styles  are  more  common.  Illustrations  are  found  in  Furctdariay 
Scaridium,  Distemma,  &c.  A  foot  ending  in  a  paii'  of  styles  is  said  by  Ehren- 
berg to  be  '  forked '  {furcate). 

In  numerous  species  the  styles  have  much  rigidity,  and  are  greatly  elon- 
gated ;  in  such  instances  they  are  known  as  styliform  setae,  or  simply  '  setce.' 
Two  such  terminate  the  trunk  in  Notommata  longiseta,  N.  cequalis,  and  in 
N.  Felis — in  the  last-named  they  are  also  curved  backwards, — whilst  but  one 
is  produced  from  the  body  in  Monocerca  (XXXYIII.  399),  Mastigocerca 
(XXXIV.  438-440),  and  in  Ratulus ;  in  the  last,  moreover,  the  base  of  the 
setae  is  surrounded  by  stiff  hairs. 

Another  very  common  termination  of  the  foot  is  by  a  pair  of  short  thick 
flaps,  moveable  on  their  base,  and  named  '  pincers,'  or  '  pincer-like  processes.* 
Such  are  seen  in  Brachionus,  Hydatina  (XL.  1),  Enteroplea  (XL.  2),  DigleTia, 
Eosphora,  Noteus  (XXXVIII.  2b),  and  in  several  Notommatce  (XXXVIII.  5, 
25,  26). 

AU  the  preceding  varieties  of  the  pseudopodium  are  modifications  of  the 
articulated  telescopic  type,  and  associated  with  a  tolerably  fii-m  cuticle.  But 
there  is  yet  another  type,  in  which  no  articulated  segments  occur,  and  which, 
from  the  softness  of  its  tissues,  is  thro^vTi  into  wrinkles  or  folds  during  con- 
traction. Illustrations  of  this  are  found  in  aU  the  urceolate  genera  of  the 
Rotatoria,  viz.  in  Coywchilus,  Lacinularia,  Melicerta,  Tuhicolaria,  Steplianoceros 
(XXXVIII.  1,  17,  19),  &c.,  and,  besides  these,  in  the  free  Megalotroclicea 
(XXXII.  374-378)  and  in  Pterodina  (XXXV.  502-504).  In  the  attached 
genera  especially,  this  form  of  pseudopodium  rather  merits  the  name  of 
^pedicle '  or  footstalk.  In  Pterodina  the  cylindrical  foot-process  is  trumpet- 
shaped,  and  discoid  at  its  free  extremity,  which  is  supposed  to  act  hke  a 
sucker.  A  suctorial  end  to  the  pedicle  is  likewise  presumed  to  exist  in  some 
or  aU  of  the  fixed  genera. 

Cilia  have  been  discovered  on  the  extremity  of  the  pseudopodium  of  Ptero- 
dina and  Tuhicolaria,  and  on  that  of  MegalotrocTia,  Lacimdaria  (XXXVII. 
10),  and  Brachionus  in  the  young  or  immature  state. 

Lastly,  a  pseudopodium  is  absent  in  Anurcea,  Asplanchna  (XXXVI.  9 ; 
XXXVII.  29-32),  Polyarthra,  Triarthra  (XXXVIII.  30),  and  Ascomorpha. 

The  observations  of  these  and  other  particulars  concerning  the  pseudopo- 
dium, its  presence  or  absence,  its  structure,  its  length  relatively  to  the  body, 
and  to  its  own  processes,  supplies  valuable  characters  in  the  systematic  distri- 
bution of  the  Rotatoria ;  and  the  details  so  derived  furnish  the  fundamental 
divisions  of  the  classification  proposed  by  Ley  dig  {see  Classification). 

The  foot-like  process  is  essentially  a  muscular  organ ;  it  contains  no  viscera, 
but  in  highly-developed  forms  some  small  bodies  supposed  to  be  glands,  and 
in  some  examples  certain  vesicular  spaces  supposed  by  some  to  be  ganglia,  by 
others,  vacuolar  thickenings  of  the  connective  tissue  (XXXVII.  17  n).     The 


406  GENEEAL  HISTORY  OF  THE  mFUSORIA. 

anus  always  opens  at  the  base  of  this  segment,  and  on  its  posterior  aspect ; 
hence  it  is  that,  though  often  called  a  tail,  it  is  really  not  homologous  with 
that  appendage  of  higher  animals  ;  and  consequently  most  writers  prefer  to 
name  it  pseudopodium,  foot-process,  or  foot.  It  certainly  has  no  evident  re- 
semblance to  a  foot,  although  anatomically  it  is  a  limb  or  member,  and  is 
functionally  an  organ  of  locomotion  and  of  support.  It  is  much  less  con- 
cerned with  motion  than  the  rotary  organ,  and,  from  its  occasional  absence, 
is  evidently  a  non-essential  organ.  A  principal  purpose  which  it  seems  to 
answer  is  that  of  a  rudder,  steering  the  animal  in  its  course  like  the  tail  of  a 
fish.  However,  occasionally,  when  developed  in  a  styliform  manner,  as  in 
Scaridium  (XXXIII.  423),  it  is  a  powerful  and  peculiar  locomotive  append- 
age, enabling  the  animal  to  leap.  The  pincer-like  termination  seems  to 
enable  the  animals  to  hold  fast  to  or  grasj)  objects,  or  to  push  themselves 
forward.  The  short  flexible  toes  developed  on  the  pseudopodium,  and  the 
supposed  discoid  extremities,  serve  to  attach  the  animal  w^hilst  the  head  may 
be  moved  fi^eely  about,  or  whilst  it  advances  in  a  leech-like  manner  by  the 
alternate  forward  movement  of  the  head  and  foot. 

Of  THE  Muscular  System  ais-d  Movements  of  the  Rotatoria.  Muscular 
System. — In  this  class  a  muscular  system,  subservient  to  the  functions  of 
locomotion,  nutrition,  &c.,  is  well  developed ;  and,  the  integument  being 
transparent,  its  structure  and  arrangement  are  distinctly  visible.  The 
muscles  (XXXVI.  5  ;  XXXVIII.  28  a)  resemble  fine  lines,  cords,  or  bands 
passing  from  one  part  to  the  other,  and  may  generally  be  distinguished  by 
being  thickened  during  contraction,  and  attenuated  by  extension.  All  those 
attached  to  the  walls  of  the  body  arise  from  the  inner  layer  of  the  integu- 
ment, which  is  thickened  at  the  spot.  They  may  be  considered,  with  refer- 
ence to  their  functions,  to  be  of  two  kinds — the  one  concerned  in  the  general 
movements  of  the  body,  the  other  in  acting  upon  special  organs  or  viscera. 
The  first  constitute  two  sets — the  one  annular,  encompassing  the  body,  the 
other  longitudinal.  The  annular  or  transverse  muscles  (XXXIII.  5,  6  t; 
XXXVIII.  26  v)  are  separated  from  each  other  by  considerable  intervals ; 
and  to  them  is  due,  in  many  species,  the  apparent  segmentation  of  the  trunk. 
They  are,  so  to  speak,  imbedded  in  the  inner  epidermic  layer.  Ehrenberg 
mistook  them  for  vessels. 

The  longitudinal  muscles  are  more  numerous  and  definite  (XXXVI.  51,91; 
XXXVIII.  28  a  ;  XL.  Im).  Mr.  Williamson  believes  that  delicate  fibres  occur 
in  the  thickness  of  the  skin  of  the  trunk,  designed  to  shorten  the  animals  by 
corrugating  the  suiface.  The  long  muscles  extending  from  the  posterior  ex- 
tremity of  the  body  to  the  rotary  organ  and  the  maxillaiy  bulb,  and  serving 
to  retract  those  parts,  are  the  most  highly  developed.  Dr.  Dobie  describes 
muscular  bands  in  Floscularia,  passing  up  between  the  lobes  of  the  ciliated 
head,  and  more  delicate  fibres  along  the  centre  of  each  lobe  towards  its  ex- 
tremity. The  muscles  of  the  tail  (foot-process)  are  also  numerous,  large, 
and  strong,  and  traceable  to  its  terminal  segments  (XXXVI.  5  b ;  XXXVIII. 
26  n)  on  the  one  side,  and  on  the  other  as  far  forward  as  the  anterior  part 
of  the  body  and  the  maxillary  bulb.  Williamson  states  that  the  fibres 
reaching  the  extremity  of  the  foot-process  are  inserted  into  a  little  concavo- 
convex  body  found  there.  By  its  muscular  apparatus  the  tail  can  be  curved, 
moved  from  side  to  side,  and  shortened,  and  in  a  few  examples,  e.  g.  Scaridium^ 
doubled  beneath  the  belly.  The  counterforce,  whereby  the  pseudopodium 
recovers  its  straight  figure  and  position  relative  to  the  body,  is  the  elasticity 
of  the  integument.  Where  the  sliding  joints  exist,  this  elasticity  must 
chiefly  reside  at  the  lines  of  junction,  since  ihe  segments  themselves  have 
great  rigidity,  and  do  not  admit  of  corrugation.    However,  the  extension  of  this 


OF  THE  EOTATOEIA.  407 

process  much  depends  on  the  influx  of  fluid  forced  into  it  by  a  general  trans- 
verse contraction  of  the  body  which  is  seen  to  precede  it.  The  extension  of 
the  body,  after  having  been  shortened  by  the  contraction  of  its  longitudinal 
muscles,  is  chiefly  due  to  the  elasticity  of  its  integument,  which  has  an  in- 
herent tendency  to  constrict  itself  or  to  lessen  its  diameter.  Prof.  Williamson 
dissents  from  this  explanation,  believing  the  extension  to  be  due  to  the  cir- 
cular muscular  bands,  as  in  the  pseudopodia  of  the  Echimis  and  starfish,  or  in 
the  tnmk  of  an  earthworm.  The  shortening  of  the  body  is  provided  for  by 
the  sliding  stnictui^e  of  its  segments,  and  by  the  wrinkling  (XL.  1)  of  its  sur- 
face (XXXIX.  1-3),  sometimes  by  both  these  modes  together,  at  others  by 
one  alone.  Even  where  its  length  is  diminished  by  the  formation  of  mere 
folds  of  the  skin,  those  folds  are  constant  in  position  and  arrangement. 
Longitudinal  folds  pretty  regularly  disposed  occur  in  the  softer-skinned 
varieties — for  instance,  in  various  species  of  Notommata  and  Hydatina. 

Muscles  supphdng  special  organs  are  seen  in  connection  with  the  trochal 
disk,  the  maxillary  head  and  jaws,  the  alimentary  canal,  and  the  reproduc- 
tive apparatus  (XXXIX.  7).  Excepting  the  muscles  moving  the  rotary 
organ,  these  will  be  best  described  in  the  account  of  the  organs  with  which 
they  are  connected. 

The  trochal  disk,  and,  indeed,  the  whole  head  supporting  it,  is  constricted, 
corrugated,  contracted,  and  moved  from  side  to  side  by  considerable  muscles, 
extending  from  it  to  the  maxillae,  and  to  the  sides  and  posterior  boundary  of 
the  abdominal  cavity  (XXXYIII.  28  a) ;  special  muscular  threads  act  upon 
particular  lobes,  prominences,  or  processes  which  may  extend  from  the  head 
or  its  ciliated  disk.  In  the  trochal  disk  of  Melicerta,  Prof.  Williamson  de- 
tected interlacing  threads  which  he  supposed  to  be  muscular ;  and  Mr.  Gosse 
has  remarked  in  the  same  animal ''  a  series  of  five  or  six  annular  threads 
set  in  the  inner  skin,  which  are  probably  muscular,  and  aid  in  the  complex 
movements  of  the  head."  Some  of  the  interlacing  threads,  which  Ehrenberg 
described  in  several  Rotatoria  (as,  for  instance,  in  Lacilunarici),  and  which 
at  one  time  he  regarded  as  vascular,  at  another  as  a  nervous  or  muscular 
network,  probably  were  muscular,  although  most  of  them  were  merely  fibres 
of  connective  tissue. 

The  extrusion  of  the  head  and  trochal  disk,  after  retraction,  is  principally 
effected,  as  in  the  case  of  the  pseudopodium,  by  the  elasticity  of  the  integu- 
ment, consentaneous  with  the  relaxation  of  the  muscular  contraction, — this 
elasticity  serving  to  unroll  the  involuted  head  and  trochal  disk,  and  to  expand 
their  parts,  and,  by  its  general  operation  on  the  body,  to  elongate  the  whole 
figure,  and  thereby  press  the  contained  fluid  forward  and  backward  against 
the  retracted  organs,  so  as  to  push  them  out.  Prof.  Williamson  would  also 
attribute  the  protrusion  of  the  head  to  the  action  of  the  circular  muscles, 
as  he  does  not  think  there  is  sufficient  proof  of  such  elasticity  independently 
of  muscular  fibres.  The  retracted  head  and  appendages  of  the  Bryozoa  are 
thrust  outward  in  a  similar  manner. 

The  cilia  of  the  trochal  disk  have  generally  been  assumed  to  be  seated  on 
a  muscular  mass,  forming  the  cushion-like  contractile  thickenings  on  the 
head  of  the  Rotatoria  (XXXVI.  93).  These  structures  display,  according  to 
Dujardin,  no  distinct  muscular  fibres ;  but  in  the  opinion  of  others,  such  are 
present.  Ehrenberg,  as  before  stated,  went  so  far  as  to  imagine,  not  merely 
a  network  of  muscular  fibrils  moving  the  entii'e  apparatus,  but  also  a  series 
of  four  muscles  at  the  base  of  each  cilium  moving  it  in  every  direction.  Such 
an  array  of  definite  muscles  to  move  an  almost  imperceptible  organ,  is  not 
only  entirely  hypothetical,  but  most  improbable.  Leydig,  on  the  other  hand, 
opposes  the  idea  of  the  muscular  natiu-e  of  the  trochal  disk,  and  regards 


408  GENERAL  HISTOEY  OF  THE  H^FUSOEIA. 

it  as  consisting  solely  of  the  soft  epidermic  tissue,  or,  which  is  nearly 
the  same  thing,  of  connective  tissue.  Much  discussion  has  arisen  concern- 
ing the  structural  composition  (i.  e.,  in  a  word,  the  histology)  of  the  muscles 
of  Rotatoria.  Dujardin  and  Ecker  questioned  the  existence  of  actual  mus- 
cular fibres,  but  recognized  a  soft  contractile  substance,  often  drawn  out 
into  threads.  The  former,  however,  inchned  to  the  belief  in  the  existence  of 
determinate  muscles,  although  observation,  when  he  wrote,  had  not  made  it 
certain.  Thus,  at  p.  611,  when  describing  a  new  species  of  Floscularia,  he 
remarks  that,  "  by  gentle  compression  of  the  animal,  five  independent  cords 
were  brought  into  view,  contractile  and  tolerably  regular  in  outline,  which 
perhaps  ought  to  be  called  muscles  ;  they  extended  through  the  pedicle  and 
to  the  extremities  of  the  lobes  of  the  rotary  organ." 

Ehrenberg  noted  the  presence  of  muscles  in  most  Rotatoria,  and  in  a  few 
specimens  believed  he  had  detected  transverse  striation, — a  fact  which  would 
establish  an  analogy  between  them  and  those  of  the  highest  animals.  This 
highly-developed  organization  was  denied  by  Siebold,  who  described  the 
muscles  to  be  of  the  non- striated  variety  so  largely  distributed  among  other 
Invertebrata  as  well  as  Yertebrata.  But  the  belief  now  prevails,  that  the 
possession  of  transversely- striated  muscles  is  one  of  the  characteristics  of  the 
Rotatoria,  although  non- striated  fibrils  may  likewise  occur. 

Leydig  thus  treats  this  subject : — "  The  element  of  muscle  is  the  primitive 
cylinder,  which  is  of  two  sorts — fine  and  thick, — the  former  in  clear  homo- 
geneous threads,  which,  when  traceable,  are  perceived  to  be  branches  of 
cells  ;  such  occurs  piTQcipally  in  muscular  networks  ;  the  latter — the  thick 
primitive  cylinder — originates  from  cells  coalesced  in  rows,  and  it,  therefore, 
presents  internally,  at  considerable  inteiwals,  the  still- remaining  cell-nuclei. 
These  cylinders  exhibit  a  gradual  advance  in  their  further  histological  phases. 
They  may  remain  homogeneous  hke  the  finest  primitive  cyhnders,  or  resolve 
themselves  into  a  homogeneous  sheath,  and  an  axial  substance  in  the  form 
of  molecules.  Lastly,  the  contents  of  the  cyhnder  may  break  up  into  mus- 
cular (sarcous)  particles,  and  therein  approximate  to  the  so-called  trans- 
versely-striped muscles,  to  which  at  length  it  may  attain  a  complete  resem- 
blance." Thus  the  cell-wall  comes  to  form  an  investing  sheath  or  sarcolemma 
of  each  fibre,  and  the  cell-contents  the  vital  contractile  substance,  or  the  sar- 
cous particles.  Leydig  adds — ''  Both  varieties  of  muscle,  simple  and  striated, 
occur  in  the  same  species,  so  that  the  gradual  transition  of  one  into  the  other 
is  unmistakeable."  The  existence  of  striated  muscle  has  been  noted  by  Ehren- 
berg in  Euchlcmis  triquetra ;  by  Oscar  Schmidt  in  Pterodina  Patina  ;  by  Perty 
in  the  foot  of  Scaridhun  longicaudum,  in  Pohjartlira  (XXXYIII.  30  m),  in 
the  marginal  muscle  of  Diglena  lacustris,  and  of  BracMonus  trijjos ;  by  Leydig 
in  Notommata  Sieboldii  (XXXYII.  32  a)  and  Noteus ;  by  Dahymple,  in  No- 
tommata  Anglica  ;  by  Williamson  and  Gosse  in  Melicerta  :  and,  without  doubt, 
it  may  be  discovered  in  most  other  genera  (XXXIX.  7). 

Perty  has  noticed  in  the  foot  of  Fhsmlaria  rows  of  granules,  and  fine 
longitudinal  striae, — an  intermediate  condition  referred  to  in  the  description 
of  Leydig,  given  above.  Bergmann  and  Leuckart  mention  in  a  note  (p.  377) 
in  their  work,  that  in  some  animals  transversely- striated  muscles  are  visible. 
Prof.  Williamson's  observations  support  some  of  Leydig's  views.  "  ^Tien  one 
of  these  muscular  fasciculi,"  writes  the  English  naturahst,  ^'  is  drawn  out 
at  full  stretch,  its  surface  is  seen  to  be  marked,  at  very  regular  intervals,  by 
dark  transverse  bars  (XXXYII.  18).  Each  fasciculas  has  a  diameter  of  about 
^J^th  of  an  inch ;  and  the  transverse  striae  recur  at  distances  of  about 
-g-fjifj-Q-th.  These  intervals  are  rather  larger  than  those  seen  in  the  fasciculi 
of  human  voluntary  muscle ....  On  rupturing  the  fasciculi  transversely,  we 


OF  THE  EOTATOEIA. 


409 


perceive  that  each  one  is  invested  by  a  delicate  sarcolemma.  This  is  well 
seen  at  the  upper  part  of  the  tail,  where,  on  the  contraction  of  the  muscle,  the 
non-elastic  sarcolemma  becomes  cornigated,  and  only  recovers  its  smooth 
aspect  when  the  muscle  becomes  relaxed.  These  rugae  of  the  sarcolemma 
must  not  be  confoimded  with  the  transverse  striae  of  the  muscular  fibre." 

Movements  op  Rotatoeia. — These  are  very  various  ;  at  the  same  time 
some  varieties  are  so  constant  in  several  genera  and  species,  as  to  furnish 
characters  of  much  utility  in  the  systematic  distribution  of  the  class.  There 
are  two  principal  modes  of  locomotion, — one  by  simple  motion  onwards,  or 
swimming,  with  or  without  rotation  of  the  body  on  its  long  axis  {e.  g.  in 
Brachionus),  the  other,  confined  to  the  family  Philodincea,  by  crawling  after 
the  manner  of  leeches,  each  extremity  of  the  body  being  alternately  fixed. 
The  latter  mode  of  locomotion  is  partaken  with  the  first,  and  the  one  or  the 
other  resorted  to  at  the  ^vill  of  the  animal. 

The  rotary  organ  is  almost  exclusively  concerned  in  producing  the  uniform 
swimming  movement  and  in  tuimng  the  animal  on  itself,  whilst  the  muscular 
tail  acts  as  a  rudder  in  directing  the  course.  The  trochal  disk  is  worked 
with  various  degrees  of  energy  and  completeness ;  when  in  full  action,  the 
velocity  attained  is  very  great. 

Usually  the  Rotatoria  swim  on  the  abdomen ;  but  exceptions  occur,  as  in 
EospTiora  Najas,  which,  Hke  the  Phyllopoda,  s^vims  on  its  back.  Noteus  and 
a  few  others  turn  on  theii'  short  axis,  or,  in  common  parlance,  head  over 
heels.  Other  exceptional  modes  of  locomotion  are  met  with  in  Scaridium,  in 
Triartlira,  and  Pohjarthra  (XXXVIII.  30,  32),  which  have,  besides  the  or- 
dinaiy  swimming  movement,  the  power  of  leaping  or  skipping, — in  the  first, 
by  means  of  the  elongated  styliform  tail,  which  can  be  doubled  under  the 
body,  and  then  suddenly  relaxed  like  a  spring ;  in  the  two  last,  by  the  aid  of 
some  rigid  bristles,  or  cin-hi,  attached  to  the  body,  and  acting  like  the  long 
legs  of  a  flea.  A  skipping  movement  is  likewise  attributed  by  Ehrenberg  to 
Notommata  longiseta,  due  to  its  double,  long,  caudal  styles,  and  an  act  of 
rowing,  by  means  of  a  long  lateral  spine  on  each  side,  to  Anurcea  biremis. 

The  preceding  remarks  apply  to  the  locomotive  Rotatoria ;  but  the  encased 
species,  although  unable  to  change  place,  have,  nevertheless,  a  considerable 
power  of  movement  within  and  about  their  urceoli.  They  can  extrude  the 
greater  part  of  their  body,  and  bend  themselves  over  the  edge  of  their  case, 
or  T^ithdi^aw  themselves  entii'ely  witliin  it.  Thej^  owe  this  latitude  of  motion 
chiefly  to  their  long  pseudopodium  or  pedicle,  which  contracts  by  throwing 
itself  into  very  numerous  and  deep  wrinkles ;  for  in  none  of  the  attached 
species  is  this  organ  articulated.  In  comparison  with  that  of  the  pedicle, 
the  capacity  of  the  trunk  of  the  animal  to  shorten  or  contract  itself  is  but 
small,  and  its  transverse  folds  few,  distant,  and  collected,  mostly  towards  the 
posterior  extremity.  The  movements,  in  fine,  of  the  urceolated  Rotatoria  are 
limited  to  those  of  extension,  retraction,  and  flexion  ;  and  the  extent  to  which 
they  may  be  exercised  is  in  direct  proportion  to  the  length  of  the  pedicle.  Xe- 
vertheless,  when  forcibly  expelled  from  its  case,  which  can  easily  be  done 
without  injury  to  the  soft  animal,  the  mature  Melicerta  swims  about  with 
considerable  velocity  by  means  of  its  ciliated  rotary  disk, — the  peduncle  being 
partially  drawn  up  towards  the  body. 

Although  incapable  of  movement  as  individuals,  a  cluster  of  such  as  live 
in  compound  masses,  Conochilus  for  instance,  may  float  about  freely,  remind- 
ing us  of  the  spheres  of  Volvox.  The  locomotive  Rotifera  also  enjoy,  in  a 
considerable  measure,  the  power  of  moving  their  own  bodies, — thus  frequently 
altering  the  relative  positions  of  the  various  parts,  and  modifying  their  general 
form.     Their  rotary  organ,  as  already  seen,  may  be  extruded  or  retracted 


410  GENEEAL  HISTOBY  OF  THE  INFTJSOKIA. 

within  the  body ;  the  body  itself  may  be  extended  at  full  length,  or  very 
much  contracted  on  itself.  So  much  may  the  whole  animal  be  contracted, 
that,  except  by  the  detection  of  the  characteristic  Rotatorial  organization,  its 
nature  would  certainly  be  mistaken.  An  illustration  of  this  is  furnished  in 
the  figures  of  Dujardin  and  Perty  (XXYIII.  4). 

The  mode  of  termination  of  the  pseudopodium  permits  many  of  the  Rota- 
toria to  attach  themselves  at  will  to  any  object,  some  (Pterodina,  for  in- 
stance) assuming  a  fijced  position  for  a  long  time  together.  "When  thus  at 
rest,  the  rotaiy  organ  may  be  retracted  or  extended ;  in  the  latter  case,  al- 
though suspending  its  function  as  an  organ  of  locomotion,  it  is  in  full  operation 
as  a  respii'atory  organ,  as  well  as  sei^ving  to  procure  food.  The  body,  more- 
over, is  often  in  active  motion  when  fixed  by  the  extremity  of  the  foot-process 
— oscillating  fi'om  side  to  side,  bending  itself,  and  even  turning  as  on  a  pivot. 

The  Digestive  System. — The  Rotatoria  possess  a  distinct  and  undoubted 
alimentary  canal,  evident  as  a  tube,  traversing  the  interior,  from  a  mouth  to 
a  posterior  outlet  or  anus,  composed  of  distinguishable  parts  "svith  accessory 
organs.  One  group  of  the  family  is  deficient  of  the  anal  outlet ;  and  in  male 
animals  the  digestive  apparatus  is  atrophied  or  wanting. 

The  digestive  tube  is  mostly  straight  throughout  its  coui'se  (XXXIX.  1 ; 
XL.  1)  ;  the  exceptions  to  the  rule  occur  with  the  encased  genera,  in  which 
the  intestine  is  curved  on  itself,  and  the  anus  advanced  forwards  to  some  spot 
beneath  the  head  (XXXVII.  17  i). 

The  parts  to  be  distinguished  in  the  alimentary  canal  are — 1st,  the  mouth 
or  oral  cavity ;  2nd,  the  pharynx  or  vestibule  (XXXYII.  19  a)  between  the 
1st  and  3rd,  the  oesophageal  head  (XXXYII.  19  6) ;  4,  the  stomach,  with 
appendages  (XXXYII.  c,  d) ;  5,  the  intestine  with  its  outlet ;  and  6,  the 
cloaca  (XXXYII.  e,f).  Each  and  aU  of  these  parts  present  great  diversity 
in  figure,  size,  and  accessory  organs ;  but  yet  in  nearly  aU  forms  the  peculiar 
type  of  the  digestive  canal  of  Rotatoria  is  well  marked. 

The  mouth  is  situated,  as  a  rule,  on  the  margin  of  the  trochal  disk,  at 
the  centre  of  its  ventral  aspect.  "Wliere  the  circlet  of  cilia  is  double,  as  in 
Lacimdaria  and  Melicerta  (XXXYIII.  21),  the  mouth,  as  we  have  already 
seen,  is  placed  between  the  two  rows  ;  and  in  Floscularia  and  Stephanoceros 
it  occupies  the  centre  of  the  area  formed  by  the  ciliated  apparatus  of  the 
head.  The  mouth  is,  moreover,  subject  to  variations  from  the  presence  of 
appendages  about  it.  Thus,  in  Melicerta,  Prof.  Williamson  describes  two  small, 
projecting,  "  flattened  lobes  with  ciliated  margins,  continuous  with  those  of 
the  '  chin,'  which  obviously  assist  in  dii-ecting  the  food  into  the  oesophagus." 
Leydig  notices,  in  Notommata  Sieboldii,  a  sort  of  upper  Up,  not  ciliated ;  and 
Huxley,  in  Lacimdaria,  states  that  the  mouth  is  vertically  elongated,  and  its 
cavity  expanded  into  "  two  lateral  pouches,  which  give  it  an  obcordate  form ; 
these  lateral  pouches  contain  the  lateral  ciliated  arches  that  become  lost 
below  in  the  cilia  of  the  pharynx."  In  Floscidaria  the  cavity  of  the  mouth 
is  funnel-shaped  (infiindibuliform)  (woodcut),  and  is  termed  by  Dr.  Dobie  the 
*' infundibulum,"  who  describes  the  edge  to  be  ''frequently  divided  into 
lobes."  ^  , 

The  mouth  opens  posteriorly  into  a  canal,  through  which  the  food  passes 
to  reach  the  "  oesophageal  bulb."  This  canal  has  unfortunately  received 
various  names,  viz.  cesophagus, pharynx,  vestibule,  infundihidum,  and  ''buccal 
funnel."  The  fii'st  term  has  likewise  been  applied  to  another  tube  intervening 
between  the  "  (esophageal  head  "  and  the  stomach ;  hence  a  looseness  of  no- 
menclature, tending  to  confusion  and  error  in  description.  If,  as  is  usually 
done,  the  name  "  oesophageal  hulh  "  be  given  to  the  jaws  and  their  muscular 
envelope,  then  that  of  oesophagus  rightly  belongs  to  the  canal  leading  thence 


OF  THE  HOTATORIA.  411 

to  the  stomach.  If,  on  the  other  hand,  the  "  oesophageal  bulb  "  be  regarded 
as  an  accessory  stomach  containing  a  dental  apparatus,  as  in  the  lobster,  then 
the  term  oesophagus  belongs  to  the  tube  extending  between  the  mouth  and 
the  bulb.  The  following  physiological  distinction  is,  however,  noted  by  Prof. 
"WiUiamson,  who  says — "  The  stomach  of  the  lobster,  with  its  dental  append- 
ages, is  that  in  which  the  digestive  process  is  carried  on.  Such  is  never  the 
case  with  the  pharyngeal  bulb  of  the  Eotifera.  The  digestive  sac  is  situate 
lower  down.  The  pharjmgeal  bulb  bears  closer  affinity  to  a  gizzard,  resem- 
bling that  of  Bowerhankia  and  other  Bryozoa,  differing,  however,  from  that 
of  a  bird,  which  is  located  helow  the  "  proventriculus  "  or  true  stomach. 
However,  some  confusion  will  be  removed  by  avoiding  the  term  "  oesophagus, ^^ 
and,  without  troubling  oiu'selves  with  the  precise  homologies  of  the  parts,  by 
naming  the  tube  between  the  mouth  and  jaws  the  '^'pharynx  "  or  "  vestibule,^' 
the  jaws  themselves  with  their  suiToimding  mass  the  ''  maxillary  bulb  "  or 
mastcuv  (Gosse),  and  the  canal  between  the  last  and  the  stomach  the  pro- 
ventricular  or  gastric  canal.  The  name  "  buccal  fiinnel "  has  been  imposed 
on  the  tube  leading  from  the  mouth  to  the  maxillary  apparatus  by  Mr.  Gosse, 
and  might  advantageously  have  been  adopted. 

To  proceed.  The  pharynx  (XXXYII.  19  a;  XL.  23  in)  varies  much  in  its 
dimensions :  sometimes  it  is  a  narrow  tapering  tube,  and,  when  contracted, 
visible  only  as  a  double  line ;  at  other  times  it  is  wide  and  short,  and  then 
especially  deserves  the  name  of  ^'  vestibule,"  since  it  ceases  to  be  a  canal. 
Several  peculiarities  in  itc  structure  occur  in  different  genera, — the  most  re- 
markable in  Floscularia  c.nd  Stephanoceros.  In  the  former  genus,  the  oral 
cavity  (infundibilum,  Dobie)  is  separated  fi'om  the  pharynx  by  a  rim  armed 
by  non-vibra.tile  cilia  :  the  pharynx  itself  is  again  subdivided  by  a  fissured 
partition  or  diaphragm,  in^o  an  upper  space  (vestibule),  and  a  lower  large  and 
very  dilatable  cavity,  called  the  "  proventriculus  "  or  "  crop."  The  crop  ends 
below  in,  or  in  some  measi^.re  embraces,  the  maxillary  bulb  (see  woodcuts, 
Part  II.).     A  similar  structure  obtains  in  Stephanoceros. 

In  Melicerta  Prof.  Williamson  observed,  within  the  pharynx  near  its 
junction  with  the  maxillary  .bulb,  the  ciliated  hning  membrane  "  to  hang  in 
several  loose,  vibratile,  longitudinal  folds  ;  "  and  Prof.  Huxley,  in  his  account 
of  Lacinularia,  gives  the  subjoined  summary  of  these  folds  and  vah^ilar  par- 
titions : — "  A  narrow  pharjTix  leads  horizontally  backwards  from  the  lower 
part  of  the  buccal  cavity,  and  becomes  suddenly  widened  to  enclose  the  pha- 
ryngeal bulb  in  which  the  teeth  are  set  (XXXVII.  19a).  "VMiere  the  buccal 
cavity  meets  the  pharynx,  a  sharp  line  of  demarcation  exists.  In  Melicerta 
two  cui'ved  lines  are  seen  in  a  corresponding  position,  and  evidently  indicate  two 
folds  projecting  upwards  into  the  oesophagus  (pharynx).  In  BracJiionus  these 
folds  are  stronger  (XL.  1  b),  while  in  Stephanoceros  and  Floscularia  (XXXVII. 
1  &  19)  this  partition  between  the  pharynx  and  what  may  be  called  the 
crop  is  still  more  marked.  From  the  inner  margin  of  the  aperture  in  the 
partition,  two  dehcate  membranes  hang  doTv^n  into  the  cavity  of  the  crop, 
which  have  a  wavy  motion  ;  and  it  is  to  them,  I  think,  that  what  Mr.  Gosse 
describes  as  an  appearance  of  ^  water  constantly  percolating  into  the  ahment- 
ary  canal '  is  due.  Dujardin  had  already  noticed  these  '  vibrating  membranes  ' 
in  Flosculanay 

Observers  coincide  in  describing  the  cilia  of  the  oral  cavity  to  extend  into 
and  line  the  pharynx  (XL.  23  m).  The  waUs  of  this  tube  are  so  very  dilata- 
ble, that  bodies  of  very  considerable  size  can  traverse  it  to  the  maxillary 
apparatus.  In  the  genera  Lacinularia,  Melicerta,  Brachionus,  Noteus,  and 
Tubicolaria,  close  to  the  wall,  or  actually  within  its  substance,  as  Ley  dig 
represents  in  Noteus,  are  two  conspicuous  structures,  described  by  that  author 


412  GEITEEAL  HISTOET  OF  THE  INFFSOEIA. 

to  be  vesicular,  and  not  improbably  salivary  glands  (XXXVIII.  27  I).  Mr. 
Huxley  alludes  to  these  structiu'es  in  the  ensuing  account : — "  On  each  side 
the  pharynx  is  a  yellowish  horny-looking  mass,  which  sometimes  appears 
cordate,  at  others,  more  or  less  completely  composed  of  two  lobes.  I  believe 
its  function  is  to  give  strength  to  the  deUcate  walls  of  the  pharynx,  and  that 
it  is,  therefore,  to  be  considered  a  part  of  the  horny  skeleton." 

The  pharynx  ends  mostly  below,  and  partially  embraces  the  "  maxillary 
bulb  "  or  "mastax,^^  which  contains  the  maxillae  or  jaws  supporting  the  ''teeth," 
and  has  its  mass  made  up  of  nuclear  cells  and  muscular  fibres  (XXXYIII. 
2Q  m).  In  the  living  animal  the  bulb  is  almost  constantly  in  motion,  con- 
tracting and  expanding  itself  in  what  some  have  called  a  "  peristaltic  "  manner. 
This  alternate  and  constant  movement,  visible  even  in  the  embryo  before  escap- 
ing from  the  eg^,  was  mistaken  by  Bory  St.  Vincent,  and  other  of  the  older 
microscopists,  for  the  pulsating  action  of  a  heart.  The  apparatus,  however, 
is  rather  comparable  to  the  gizzard  of  birds,  or  to  the  tooth -crushing 
mechanism  in  the  stomach  of  lobsters  and  other  Crustacea,  though  not, 
indeed,  homologous  with  it.  The  ''  maxillary  bulb  "  is  bulky,  more  or  less 
globose,  with  a  prevailing  tendency  to  a  triangular  figure  "sv'ith  rounded 
angles  (XL.  20,  23,  24).  Sometimes  it  is  oval  or  ovoid,  and  still  more  com- 
monly heart-shaped,  from  being  notched  or  furrowed  on  one  side,  indicating 
a  bilobed  structure.  In  Melicerta  Mr.  Gosse  figures  and  describes  a  third 
lobe,  below  the  usual  "two  globose  bodies  (or  rather  the  bilobed  single 
mass),  equally  hyaline  and  probably  muscular,  which  seems  united  to  the 
two  others,  and  alters  in  form  as  they  and  the  jaws  work,  lengthening  down- 
ward as  they  approach,  and  dilating  and  shortening  as  they  recede " 
(XXXVII.  23). 

The  mass  of  the  "  maxillary  bulb  "  surrounding  the  maxillse  has  been 
generally  assumed  to  be  muscular,  and,  as  such,  actively  concerned  in  work- 
ing the  contained  jaws.  Gosse  calls  it  a  "  muscular  sac,"  and  has  even 
attempted  the  description  of  its  component  miLscular  bands.  Leydig  has  re- 
presented the  jaws  to  be  acted  on  by  exquisitely  striated  muscles  (XXVII. 
31).  Prof.  Williamson  admits  the  existence  of  muscles  affixed  to  the  pro- 
cesses of  the  jaws,  but  states  that  the  conglobate  organ  in  which  these  are 
imbedded  "  is  transparent,  and  composed  of  numerous  large  cells,  each  of 
which  contains  a  beautiful  nucleus  with  its  nucleolus.  The  cells  are  only 
seen  when  the  organ  is  ruptui'ed  between  two  plates  of  glass,  when  they 
readily  separate  from  one  other ;  but  the  nuclei,  with  their  contained  nucleoU, 
are  distinctly  visible  in  the  living  animal.  Delicate  muscular  thi^eads 
most  probably  penetrate  tliis  organ  to  reach  the  dental  apparatus,  though  I 
have  not  yet  detected  them."  Here  a  great  discrepancy  of  opinion  appears, 
between  Mr.  "Williamson  and  Leydig  and  most  other  writers,  respecting  the 
constitution  of  the  globose  mass  of  the  maxillary  bulb,  and  such  as  only 
reiterated  examination  can  remove. 

Dr.  Leydig  asserts  that  the  bulb  is  covered  externally  by  a  chitinous 
membrane,  of  the  same  nature  as  the  cuticle,  and  that  the  existence  of  a  like 
membrane  in  its  interior,  developed  for  a  special  end,  constitutes  the  maxillae 
and  appendages,  just  as  bristles  and  homy  plates  and  processes  are  developed 
out  of  the  external  cuticle. 

The  maxillary  apparatus,  contained  within  the  soft  mass  of  the  bulb,  is 
visible  without  any  preparation,  but  may,  from  its  hardness,  be  detached  by 
strongly  compressing  or  crushing  the  animal.  Although  much  denser  than 
the  soft  tissues  of  the  body,  yet  like  them  the  dental  apparatus  disappears 
by  decomposition.  Ehrenberg  having  an  enormous  number  of  Brachioni 
in  a  vessel  of  water,  evaporated  the  fluid,  and  ha^ing  burnt  the  desiccated 


OF  THE  ROTATOEIA.  413 

animals,  examined  their  ashes  chemically,  convinced  himself  they  contained 
much  phosphate  of  lime,  derived,  as  he  supposed,  from  the  maxillte.  Mr. 
Gosse  likewise  concludes  that,  from  their  great  solidity  and  density,  and 
from  the  action  of  menstrua  upon  them,  they  are  of  calcareous  nature. 

The  construction  of  the  jaws,  and  the  number  and  position  of  the  transverse 
bars  or  '  teeth,'  afforded  Ehi^enberg  characters  of  primaiy  importance  in  the 
construction  of  his  system  ;  and  he  indicated  three  leading  types,  under  which 
all  the  Rotatoria  could  be  classed,  viz. : — "  1 ,  Affom^Jiia,  toothless  ;  2.  Gym- 
nogomphia,  free-toothed  (unconnected) ;  3.  JDesmogomjphia,  connected  or 
attached  teeth.  In  Gymnogompliia  the  teeth  are  fi-ee  in  front,  and,  like 
the  fingers,  united  behind  by  a  common  band — the  jaw ;  in  Desmogomj)hia 
they  are  attached  transversely  across  the  jaw-piece,  like  an  arrow  lies  across 
the  bow.  In  the  former,  again,  the  teeth  in  each  jaw  are  single  or  several  in 
number ;  in  the  latter,  either  two  or  manj'.  Hence  there  are  5  groups  : — 
1.  Agomphia — e.g.  Iclithydium,  Cluetonotus,  Enteroplea)  2.  Monogomphia 
(one-toothed) — Pleurotrocha,  Furcularia,  Cycloglena,  3IonostyIa,  Lepadella ; 
3.  Polygompliia  (many-toothed) — Hydatina,  several  Notommatce,  EucJdanis, 
Steplianoceros,  Bracliionus,  (S:c. ;  4.  Zygogomphia  (twin-toothed) — CaUklinaj 
Eotifer,  Actinurus,  Philodina,  Monolahis,  and  Pterodina ;  5.  Lochogomphia 
(teeth  set  in  rows) — Ptygura,  Megalotrocha,  Melicerta.^' 

This  classification  of  the  Eotatoria,  however,  Ehi^enberg  confessed  to  be 
imperfect,  as  wanting  repeated  researches  to  fix  on  the  truly  generic  and 
specific  resemblances  and  difierences  of  the  dental  apparatus.  In  fact, 
although  the  conditions  may  be  constant  in  the  same  species,  yet  thet  are  so 
minute,  that  they  frequently  can  be  made  out  very  imperfectly  and  with  un- 
certainty ;  and,  besides  this,  the  variations  in  the  positions  of  the  animal 
when  mo\Tiig  its  body  appear  so  materially  to  alter  the  form  of  the  mechanism 
in  question,  that  careful  students  often  differ  respecting  it  in  the  case  of  the 
self-same  animal.  To  illustrate  these  remarks,  we  may  appeal  to  the  descrip- 
tion of  MeUcerta  ringeiis,  as  separately  and  independently  detailed  by  Prof. 
WiUiamson  and  by  Mr.  Gosse.  The  latter  represents  three  or  four  transverse 
bars  or  teeth  to  each  lateral  jaw  (XXXYII.  23),  the  former  above  a  dozen 
(XXXYII.  26) ;  the  one  detects  a  trilobed  bulb,  the  other  speaks  of  a  single 
conglobate  organ,  but  which,  from  his  figures,  might  be  called  bilobed.  Addi- 
tional illustrations  of  such  doubt  and  uncertainty  are  to  be  found  on  compar- 
ing the  descriptions  of  the  maxillary  organs  recounted  by  any  two  observers. 
Ehrenberg's  representations  are  now  set  aside  by  aU,  improvements  in  the 
microscope,  and  repeated  examinations,  having  demonstrated  their  erroneous- 
ness.  The  whole  tribe  of  Agomphia  or  toothless  Rotatoria  must  be  set 
aside ;  for  it  seems  a  weU-established  rule,  that  no  female  of  the  class  is  de- 
ficient of  dental  organs,  and  the  genera  Iclithydium  and  Chrdonotus  cannot, 
as  before  shown,  be  retained  in  the  class.  Enteroplea,  again,  is  in  all  proba- 
bility a  male  animal,  and  Cyphonantes  wants,  according  to  Ehrenberg's  plates, 
the  characteristic  organization  of  Rotatoria  in  aU  its  details.  But  it  would 
be  useless  to  continue  an  analysis  of  the  other  types  established  by  the  Berlin 
Professor,  the  existence  of  any  one  of  which,  having  the  particulars  of  struc- 
ture assigned  to  it,  is  not  to  be  demonstrated.  What  is  worse,  we  must  con- 
fess to  the  absence  of  any  one  detailed  account  of  the  dental  apparatus  which 
can  be  received  with  implicit  confidence  in  its  accuracy ;  so  greatly  have  the 
leading  writers  on  the  Rotatoria  differed  among  themselves  in  describing  the 
mechanism  in  question. 

Dujardin  distinguished  the  following  parts  in  the  maxillary  apparatus  : — 
the  ^'fulcrum''  or  support,  a  single  central  piece  with  two  articulated  branches  ; 
the  ■*  scapus  "  or  lateral  branch  ending  in  an  articulated  point,  "  acies,"  and 


414  GENEEAL  HISTOBT  OF  THE  INFUSORIA. 

itself  single  or  multiple,  which  is  the  jaw  properly  so  called.  In  most  cases, 
says  Siebold,  the  homy  jaws  consist  of  two  bent,  geniculate  processes,  an 
anterior  and  a  posterior ;  the  latter  gives  attachment  to  the  muscles  moving 
the  apparatus,  whilst  one  or  several  teeth  are  developed  on  the  former.  In 
some  many- toothed  Rotatoria,  each  jaw  is  provided  with  three  homy  arches 
{e.  g.  in  Philodina,  Lacinularia,  and  Melicerta).  Two  of  these  arches  (arcus 
superior  et  inferior)  are  turned  inwards,  whilst  the  third  (arcus  exterior)  is 
directed  outwards.  To  the  under  arch  the  muscles  of  the  jaw  are  attached, 
which  move  the  other  two  arches,  with  their  transverse  teeth,  against  each 
other. 

"Williamson  gives  the  following  particular  account  of  the  grinding  apparatus 
of  Melicerta  : — "  The  gastric  teeth  consist  of  two  essential  portions,  a  pair  of 
strong  crushing  plates,  which  braise  the  food,  and  various  appendages  afford- 
ing leverage  and  facilitating  the  action  of  the  muscles  upon  them.  The 
crushers  are  two  broad  elongated  plates  (XXXYII.  26),  each  being  about 
■g-i-g-th  of  an  inch  long,  and  separated  from  each  other  at  the  mesial  line,  near 
which  they  become  much  thickened.  From  each  of  these  plates  there  proceed 
laterally  numerous  parallel  bars,  all  of  which  are  somewhat  thickened  at  their 
inner  extremities  where  they  are  attached  to  the  plates,  whilst  at  their  oppo- 
site ends  they  are  united  mth  the  others  of  the  same  side  by  a  curved  con- 
necting bar  (fig.  26),  from  the  outer  sides  of  which  are  given  oif  various 
loops  and  processes.  The  three  uppermost  of  these  bars  are  the  largest,  the 
rest  gradually  diminishing  in  size  and  strength  as  we  descend,  the  inferior 
ones  being  almost  invisible.  Prom  the  upper  extremities  of  the  two  crushers 
there  project  upwards  and  backwards  two  slender  prolongations  imited  by  a 
kind  of  double  hinge-joint  near  their  apex,  where  they  not  only  play  upon 
each  other,  but  also  on  a  third  small  central  fixed  point,  lodged  in  a  little 
conglobate  cellular  mass.  Ehrenberg  only  describes  three  transverse  bars 
on  each  side,  which  he  regards  as  teeth.  It  is  obvious  that  he  has  only 
noticed  the  thi^ee  upper  and  larger  pairs.  It  is  equally  evident  that  these 
transverse  teeth,  as  he  terms  them,  do  not  move  upon  the  strong  longitudinal 
plates,  as  he  imagines,  but  are  firmly  united  with  them.  Muscles  are  either 
attached  to  the  divergent  peripheral  processes,  or  to  the  cellular  mass  in 
which  these  processes  are  imbedded,  causing  the  entire  apparatus  to  separate 
into  two  parts  along  the  mesial  line  by  means  of  the  hinge  joint,  the  so- 
called  teeth  merely  transmitting  the  motor  force  to  the  two  longitudinal 
plates.  These  latter  appendages  are  thus  made  to  play  upon  each  other  with 
great  power,  and  act  as  efficient  crushers,  bruising  the  food  before  it  passes 
into  the  stomach,  as  is  the  case  with  the  gastric  teeth  of  the  Crustacea. 
From  the  above  remarks  it  will  be  seen  that,  though  in  its  construction  the 
dental  apparatus  is  more  complex  than  is  represented  by  Ehrenberg,  in  its 
mode  of  working  it  is  less  so." 

Prof.  Huxley,  to  quote  another  accurate  English  observer,  has  seen  in 
Lacinularia  sociaJis,  as  also  in  Stephanoceros,  the  "  pharyngeal  armatui'e  com- 
posed of  four  separate  pieces  (XXXYII.  30)  :  two  of  these  (which  form  the 
*  incus '  of  Mr.  Gosse)  are  elongated  triangular  prisms,  applied  together  by 
their  flat  inner  faces ;  the  upper  faces  are  rather  concave,  while  the  other 
faces  are  convex,  and  upon  these  the  two  other  pieces  (the  mallei  of  Mr. 
Gosse)  are  articulated.  These  last  are  elongated,  concave  internally,  convex 
extemally,  and  present  two  clear  spaces  in  their  interior  ;  fi'om  their  inner 
surface  a  thin  curved  plate  projects  inwards.  At  its  anterior  extremity  this 
plate  is  brownish,  and  divided  into  five  or  six  hard  teeth  with  slightly  en- 
larged extremities.  Posteriorly  the  divisions  become  less  and  less  distinct, 
and  the  plate  takes  quite  the  appearance  of  the  rest  of  the  piece."     This  is 


OF  THE  EOTATOEIA.  415 

essentially  the  same  structui-e  as  that  of  the  teeth  of  Notommata  described  by 
Mr.  Dalrymple  {PhiJ.  Trans.  1849),  and  by  Mr.  Gosse  (XXXVI.  6)  {T.  M.  S. 
1851),  and  veiy  different  from  the  stirrup -shaped  "  armature  "  represented 
by  Ehrenberg  and  Dujardin  in  Lacinularia.  Prof.  Huxley  notes,  moreover, 
the  omission  of  the  two  pieces  constituting  the  "  incus,"  in  the  description 
given  of  the  apparatus  by  Leydig. 

The  last-named  author  has  attempted  no  general  description  of  the  dental 
organs,  and  has,  in  the  specific  details,  so  briefly  adverted  to  their  structure, 
that  he  would  seem  to  attach  to  them  little  importance.  He  has,  however, 
figured  the  maxillse  of  Notommata  Sieboldii  (XXXVII.  31),  wishing  especially 
to  represent  the  transversely-striated  muscles  acting  upon  them.  He  men- 
tions the  maxillae,  which  occupy  the  spacious  angular  maxillary  bulb,  as  ex- 
hibiting a  bifid  or  forked  portion,  hooked  at  the  ends,  with  a  spine  projecting 
from  the  inner  side,  and  a  margin  on  the  outer  side  :  to  the  latter  the  strong 
muscles  for  opening  and  shutting  the  maxillae  are  afiixed.  The  transverse 
striation  of  the  muscles  is  particularly  brought  into  view  by  pressure  on  the 
apparatus.  Cohn  (Zeitschr.  1855)  has  some  very  precise  details  respecting 
the  structure  of  the  dental  mechanism  of  Hydatina  senta,  and  of  two  or  three 
other  Kotatoria ;  but  it  would  lead  us  beyond  our  scope,  to  transfer  them  to 
our  pages. 

The  most  elaborate  attempt  to  unfold  the  true  structure  of  the  maxillae, 
and  to  reduce  all  the  varied  foi-ms  to  a  common  type  the  essentials  of 
which  are  always  detectable  notwithstanding  any  degree  of  general  modifi- 
cation, has  been  made  by  Mr.  Gosse.  The  diversity  of  descriptions  met  with 
among  writers  on  the  Rotatoria,  respecting  the  maxillae,  is  materially  due  to 
the  hmited  examination,  undertaken  by  any  one  of  them,  of  those  organs, — 
each  observer  having  studied  some  one,  or  at  most  but  a  few  species,  and 
then  describing  the  peculiar  maxillary  organs  met  with  as  pervading  the 
whole  class :  such  as  is  essential  to  the  discovery  of  their  true  relations,  a 
comparison  of  their  structure  among  all  the  genera,  has  been  neglected.  The 
right  mode  of  study  seems  to  have  been  undertaken  by  Mr.  Gosse ;  but  his 
conclusions  require  to  be  tested  by  repeated  observation  {Phil.  Trans.  1855). 
His  method  of  manipulation,  for  the  purpose  of  examination,  is  well  worth 
noting.  He  says  {op.  cit.  p.  424), — "  In  the  course  of  experiments  with 
various  chemical  reagents  on  these  animals,  I  found  that  a  solution  of  potash 
had  the  effect  of  instantly  dissolving  the  flesh  and  most  of  the  viscera,  leaving 
the  general  integument,  the  walls  of  the  pharyngeal  bulb,  and  all  the  solid 
parts  of  the  manducatory  apparatus  uninjui-ed.  In  most  cases,  also,  the  last- 
named  organs  are  expelled  from  the  visceral  cavity  by  the  contraction  of  the 
integuments,  so  that  they  float  at  large  in  brilliant  clearness,  undimmed  by 
intervening  tissues,  and  as  patent  to  observation  as  when  crushed  between 
plates  of  glass,  with  the  advantage  of  all  the  parts  being  unbroken  and  re- 
taining their  relative  positions.  Now,  by  turning  the  screw  of  the  compres- 
sorium,  flattening  or  deepening  the  drop  of  water,  waves  were  communicated 
to  it,  by  means  of  which  the  floating  bulb,  being  nearly  globular,  was  made 
to  revolve  irregularly,  and  thus  to  present,  in  succession,  various  aspects  to 
the  eye." 

To  display  his  researches  ever  so  briefly,  we  must  first  introduce  his  no- 
menclature. The  gizzard  or  enclosing  maxillary  bulb,  he  calls  the  mastacc 
(XL.  20) ;  and  declares  it  to  be  a  muscular  trilobate  sac.  The  maxillce  con- 
sist of  two  geniculate  bodies  {mallei)  (XL.  20  h),  and  a  third  on  which  they 
work  {incus)  (XL.  20  /).  Each  malleus  is  of  two  parts — 1,  the  manuhium 
(c),  and  2,  the  uiicus  {e), — united  by  a  hinge  joint.  The  manubrium  is  a 
piece  of  irregular  form,  consisting  of  carince  of  soHd  matter,  enclosing  three 


416  GENERAL  HISTORY  OF  THE  IXFUSORIA. 

areas,  which  are  filled  with  a  more  membranous  substance.  The  uncus 
consists  of  several  slender  pieces,  more  or  less  parallel,  arranged  like  the  teeth 
of  a  comb,  or  like  the  fingers  of  a  hand. 

The  incus  consists  of  two  r^zmi  (g)  articulated  by  a  common  base  to 
the  extremity  of  a  thin  rod  (fulcrum)  (h)  in  such  a  way  that  they  can  open 
and  close  by  proper  muscles.  The  fingers  of  each  "  uncus  "  rest  upon  the 
corresponding  ramus,  to  which  they  are  attached  by  an  elastic  ligament.  The 
"  mallei  "  are  moved  to  and  fro  by  distinct  muscles ;  and  by  the  action  of  these 
they  approach  and  recede  alternately,  the  "  rami "  opening  and  shutting 
simultaneously,  Avith  a  movement  derived  partly  from  the  action  of  the 
"  mallei  "  and  partly  from  their  own  proper  muscles. 

Under  all  the  variations  in  form  and  disposition  of  the  parts  presented  in 
Euchlanis,  Anurcea,  Synchceta,  Diglena  (XL.  24),  PoJyartlira,  Asplmichna, 
Monocerca,  &c.,  the  same  type  prevails  as  in  Brachionus  (XL.  20-23)  (which 
is  the  genus  Mr.  Gosse  uses  as  his  standard  of  comparison).  The  modifica- 
tions in  those  genera  may  in  general  "  be  considered  as  successive  degenera- 
tions of  the  '  mallei,'  and  augmentations  of  the  incus.  In  another  collection 
of  genera  (the  fixed  or  urceolate),  the  organs,  although  essentially  the  same 
as  in  the  former  t}^e,  are  somewhat  disguised  by  the  excessive  dilatation  of 
the  *  mallei,'  and  by  the  soldering  of  the  unci  and  rami  together  into  two 
masses,  each  of  which  approaches  in  figure  the  quadrant  of  a  sphere.  The 
ascribed  '  stii^rup-shaped '  armature  of  the  Philodincea  arises  from  misappre- 
hension ;  for  it  has  no  essential  diversity  from  the  common  type,  their  analogy 
with  the  genera  last  mentioned  being  abundantly  manifest,  though  they  are 
stiU  fui'ther  disguised  by  the  obsolescence  of  the  '  manubria.'  In  Floscularia 
(XL.  25,  26)  and  Steplianoceros  (XL.  27,  28)  the  most  aberrant  Rotatoria, 
the  *  mastaoc  '  is  wanting  ;  and  in  the  former  genus  the  incus  and  manubria 
are  reduced  to  extreme  evanescence,  though  the  two -fingered  unci  show, 
in  their  structure,  relative  position,  and  action,  the  true  analogy  of  these 
organs." 

As  to  their  homology,  he  argues  they  have  no  true  afiinity  with  the  gastric 
teeth  of  the  Crustacea,  though  he  states  his  conviction  that  the  Rotifera  belong 
to  the  great  Arthropodous  division  of  animals. 

"  The  action  of  the  homy  jaws,"  Mr.  Gosse  remarks  in  his  account  of 
Melicerta,  ''  is  not  exactly  that  of  two  flat-surface  mullers,  working  on  each 
other  in  a  grinding  manner,  but  a  complex  motion  impossible  to  be  explained 
by  words."  Since  the  nature  of  om- work  has  compelled  us  to  limit  ourselves 
to  a  mere  outline  of  Mr.  Gosse's  most  elaborate  and  important  researches  on 
the  manducatory  organs  of  the  Botifera,  we  cannot  too  strongly  recommend 
the  student  to  refer  to  that  gentleman's  essay  in  the  Transactions  of  the  Royal 
Society,  both  for  a  more  complete  acquaintance  with  his  A-iews  and  discoveries 
relative  to  those  particular  organs,  and  for  a  host  of  valuable  details  on 
other  parts  of  the  anatomy  of  this  class  of  animals. 

Some  Rotatoria,  the  so-called  single-toothed  species,  have  the  faculty  of 
protruding  their  maxillae  beyond  the  mouth,  and  of  using  them,  in  this  curious 
position,  as  prehensile  organs.  Thus  the  animal  is  enabled  to  seize  upon 
prey  without  awaiting  its  being  casually  engulfed  within  the  vortex  of  its 
ciliated  head.  Examples  are  found  in  Synchceta  mordax,  in  Distemma 
Forficula,  and  in  Diglena  (XL.  24). 

The  maxillary  bulb  communicates  immediately,  or  by  the  medium  of  a  mem- 
branous canal,  with  the  stomach — the  next  division  of  the  aHmentary  tube. 
This  canal  is  very  commonly  termed  the  oesophagus  ;  but  we  prefer  to  call  it 
the  pro  ventricular  canal,  to  avoid  confusion  and  doubtful  analogies.  It  com- 
mences at  the  posterior  inferior  part  of  the  bulb. 


OF  THE  EOTATOHIA.  417 

Leydig  represents  this  tube  to  be  lined  by  a  continuation  of  the  chitinous 
inner  layer  of  the  maxillary  bulb,  and  uses  this  view  to  explain  the  distinct- 
ness of  outline  frequently  remarkable  in  the  walls  when  of  considerable 
thickness,  e.  g.  in  Notommata  centrura  (XXXYIII.  26  q)  and  N.  tardigrada. 
This  sharj)  contour  is  especially  manifest  dimng  contraction  of  the  canal, 
whereby  it  is  thrown  into  transverse  folds  or  wrinkles,  noticed  by  Ehrenberg 
under  the  title  of  "  hard  oesophageal  folds,"  and  elsewhere  of  a  "  rather  firm 
framework  at  the  commencement  of  the  oesophagus."  Leydig  adds — "  The 
organs  described  by  Ehrenberg  in  Notommata  saccigera,  as  '  large  vibrating 
gills,'  must,  I  think,  be  considered  transverse  folds  of  the  chitin  membrane 
in  question."  The  existence  of  so  dense  a  lining  to  the  gastric  tube  implies 
the  absence  of  cilia  on  its  surface  ;  and,  in  fact,  Leydig  declares  he  has  never 
seen  the  least  sign  of  such  organs,  although  both  Perty  and  Williamson  affirm 
their  existence.  The  folds  into  which  this  tube  is  thrown  when  contracted 
are  occasionally  {e.  g.  in  Notommata  Sieboldii)  (XXXVII.  22)  longitudinal 
instead  of  transverse.  Mr.  Gosse  says  of  it  that  it  is  "  composed  of  longitu- 
dinal and  annular  contractile  tissue,"  and  that,  at  least  in  Asplanchna  prio- 
donta  (XXXYI.  9 1),  "  it  is  capable  of  immense  dilatation,  but  commonly  takes 
the  form  of  a  slender  tube  Avith  the  lower  extremity  swoUen,  where  an  oval 
pancreatic  gland  is  attached  on  each  side.  The  passage  of  a  small  morsel, 
such  as  a  Chilomonas,  shows  that  the  walls  of  this  organ  are  thick,  leaving 
only  a  slender  tube  when  corrugated."  However,  in  different  species  the 
width  and  the  thickness  of  its  waRs  vary  much.  The  proventricular  canal 
has  a  considerable  length  in  Diglena  and  Sgnchceta  ;  it  is  rather  long  in 
Triarthra,  Lacimdaria,  and  Hydatina,  and  very  short  in  Euclilunidota,  Bra- 
chioncm,  and  Melicerta.  In  not  a  few  genera  it  is  altogether  wanting,  the 
maxillary  bulb  being  superposed  immediately  upon  the  stomach :  such  are 
Ascomorpha  and  the  genera  of  the  family  Philodincea. 

The  stomach  succeeds  to  the  gastric  canal  as  a  distinct  segment  separated 
from  the  alimentary  tube  below  by  a  constriction,  and  is  remarkable  also  in 
general  by  its  greater  capacity  (XL.  1  e).  Leydig  affirms  that  a  portion  of 
the  digestive  canal  separated  from  the  rest  by  a  constriction,  and  essentially 
representing  a  stomach,  exists  in  aU  true  Rotatoria;  but  other  writers  describe, 
as  in  Philodina  (XXXYIII.  1,  2),  and  in  Lindia  (XL.  1,  3),  the  existence  of 
a  straight,  slender,  fLmnel-Like  alimentary  canal  extending  from  the  mouth 
to  the  cloaca  without  any  constriction  or  any  stomach  dilatation.  In  Hy- 
dat'ina  and  Synchceta,  Perty  says  the  canal  is  uniform  in  calibre,  without  any 
stomach-Hke  expansion  ;  yet  Cohn  distinguishes  the  narrower  lower  end  of 
the  alimentary  tube  of  Hydatina  as  an  intestine,  because  it  is  less  constantly 
occupied  with  food,  is  colouiiess,  and,  unlike  the  stomach,  has  no  such  cells 
on  its  waU.  Moreover,  as  an  irregularity,  he  twice  met  with  a  sphincter- 
hke  constriction  {pylorus)  separating  the  two.  In  Euchlanis  and  Brachionus, 
on  the  other  hand,  the  division  is  clearly  indicated  (XXXIX.  16). 

The  opposing  statements  of  authors  on  this  question  may  probably  be  re- 
conciled on  the  supposition  that,  of  different  observers,  some  have  viewed  the 
canal  when  it  has  been  fiiU  and  distended,  others  when  empty  and  contracted, 
and  that  the  constriction  indicating  a  definite  stomach  has  appeared  only 
during  repletion,  just  as  happens  with  the  human  stomach,  which,  when  full 
and  engaged  ia  digestion,  is  deeply  constricted,  and  for  the  time  appears 
almost  like  a  double  organ. 

Ehrenberg  distinguished  four  types  of  Rotatoria,  according  to  the  cha- 
racters of  the  alimentary  tube,  which  he  respectively  named — 1.  Trachelo- 
gastnca ;  2.   Coelogastrica  ;  3.   Gasterodela ;  4.   Trachelocystica. 

1.  The  Tracheloqastrica  comprehended  animals  having  a  long  filiform  gullet, 

2e 


418  GENEEAL  niSTOEY  OF  THE  INErSOEIA. 

rapidly  transmitting  and  not  retaining  the  food,  and  terminating  in  a  compa- 
ratively short  conical  intestine,  without  a  stomach  dilatation,  e.  g.  Icliihydium, 
Chcetonotus. 

2.  Ccelogastnca,  Rotatoria  with  a  very  short  gullet,  a  long  conical  in- 
testine, and  no  stomach,  e.  g.  Hydatina,  Synchceta. 

3.  Oasterodela,  those  Rotifers  having  an  evidently  developed  stomach,  or 
a  dilatation  of  the  alimentary  canal  limited  by  a  definite  constriction, 
e.  g.  Euclilanis,  Bracliionus,  LeixideUa,  Biglena,  &c. 

4.  Tracliehcystica,  with  an  indistinct  gullet,  but  having  a  very  long,  fili- 
form, small  intestine,  in  which  the  food  is  detained,  and  also  a  large  globular 
intestine  (rectum  or  cloaca)  placed  close  to  the  discharging  orifice,  e.  g.  Rotifer, 
Act'inurus,  PMlodina. 

Subsequent  independent  observers  have  been  able  neither  to  recognize  all 
these  distinct  types  of  structure  nor  to  admit  their  value.  Leydig,  in  fact, 
insists  that  the  so-called  "  gasterodelous  "  type  is  the  only  one  seen  in  Rota- 
toria ;  but,  as  just  now  stated,  several  authors  admit  the  existence  of  a  simple 
conical  or  tapering  alimentary  tube,  without  dilatation  or  stomach,  in  several 
of  the  class. 

The  Tnwhelogastrica  are  represented  only  by  beings  which  are  now,  by  gene- 
ral consent,  excluded  from  the  Rotifera.  The  termination  of  the  intestine  in 
a  dilated  sac-like  expansion,  in  which  also  the  generative  canals  end,  whence 
its  name,  "  cloaca,^'  is  the  rale ;  or,  to  use  Ehrenberg's  term,  the  majority  of 
the  Rotatoria  are  Trachelocystica. 

The  stomach  dilatation,  like  the  rest  of  the  alimentary  canal,  is  capable  of 
great  expansion,  by  which  its  figui^e  is  considerably  altered.  Usually  but 
one  gastric  cavity  has  been  described  ;  but  in  some  species  there  is  a  second, 
and  Huxley,  in  his  history  of  Lacinidaria  (XXXVII.  19),  describes  three 
portions  or  divisions  between  the  gastric  canal  and  the  rectum, — the  fii'st 
with  two  pyriform  sacs  opening  into  it,  the  middle  one  frequently  with  several 
short  cellular  caeca,  and  the  lowest  ^ith  several  cellular  cseca  projecting  ex- 
ternally, and  clothed  within  with  very  long  cilia.  According  to  Prof.  Wil- 
liamson, the  stomach  of  Mdkerta  (XXXYII.  17)  consists  of  an  upper  and 
lower  segment,  separated  the  one  from  the  other  by  a  marked  though  vary- 
ing constriction, — the  upper  stomach  elongated,  the  lower  almost  spherical, 
Mr.  Gosse  describes  this  same  organization  in  Melicerta,  but  calls  the  upper 
segment  "a  wide  cylindrical  stomach,"  and  goes  on  to  say  that  the  food 
passes  from  this  into  a  globose  intestine  which  ends  in  a  slender  but  dila- 
table rectum. 

A  similar  double  organ  is  found  in  Fhscularia,  Btephanoceros  (XXXVII. 
1/),  and  Tubicolaria.  Moreover  Ehrenberg  noted  a  sac  attached  to  the 
stomach  of  Megcdotrocha,  which  he  called  a  caecum.  The  configuration  of 
the  stomach  is  otherwise  altered  by  tubular  and  saccular  appendages,  and  in 
a  few  instances  is  lobular,  as  stated  by  Mr.  Gosse  in  Asplancli^ia  (XXXYI. 
9  s).  Ehi'enberg  states,  at  p.  399  of  his  great  work,  that  the  stomach  of 
Lacinidaria  is  complicated  by  two  blind  tubes  (intestines),  and  yet,  at  p.  403, 
reverses  this  statement  by  saying  that  it  is ''  without  bhnd  intestine-hke  ap- 
pendices." Leydig  admits  the  latter  as  the  truth ;  but,  as  already  seen, 
Huxley  remarked  two  pyriform  sacs  attached  to  the  first,  and  caeca  to  each 
of  the  other  two  segments.  Ehrenberg  further  describes  caecal  appendages  to 
the  stomach  of  Notommata  clavidata,  and  of  Diglena  Jamtstris,  but  such  were 
probably  the  turgid  stomach-cells  presently  noticed. 

The  tissues  or  histological  elements  entering  into  the  formation  of  the 
stomach  are — 1,  a  limiting  external  membrane,  and,  2,  an  internal  layer  of 
epithelium  (XL.  4).     The  former  is  the  same  tissue  with  that  constituting 


0^  THE  ROTATORIA.  419 

the  walls  of  other  portions  of  the  alimentary  canal,  and  is  supposed  by  many 
to  contain  muscular  fibrilloe,  although  so  very  thin,  pellucid,  and  apparently 
structiu'eless.  Ley  dig,  however,  calls  it  a  homogeneous  connective  tissue. 
The  lining  of  epithelium  is  made  up  of  large  turgid  cells,  rendering  the  wall 
thick  and  of  a  pulpy  appearance  (XXXVIII.  26/).  In  young  animals  the 
epitheUal  cells  are  coloiu'less ;  but  in  adult  beings  their  granular  contents 
are  coloured  and  interspersed  with  fat-globules,  whence  it  is  that  the  walls 
of  the  stomachs  assume  a  yellowish  hue  often  intermingled  with  green  and 
broAvn  tints.  The  cells,  moreover,  commonly  possess  a  nucleus  and  a  nucle- 
olus, and  their  free  surface  is  constantly  ciliated.  They  are  readily  detached 
from  the  subjacent  membrane  and  from  each  other,  and  are  then  seen  to  have 
a  spherical  or  ovoid  figui'e. 

"  The  great  thickness  of  the  epithelial  layer,"  writes  Mr.  Williamson,  ^'  as 
compared  with  the  entire  diameter  of  the  organ,  is  curious  :  whilst  the  latter 
averages  about  2^1^^  ^^  ^^  inch,  the  former  is  often  not  less  than  y^th, 
or  -i-th  of  its  entire  diameter.  The  cells,  when  detached,  vary  in  size,  from 
a  diameter  of  ^^^^^th  to  ^.  ^}^  ^th  of  an  inch ;  one  of  these  was  fringed  with 
ciha  y^T^-jjth  of  an  inch  long,  and  had  a  nucleus  y^J^th  of  an  inch.  After 
being  detached,  some  of  the  ciliated  cells  floated  slowly  away,  like  so  many 
animalcules." 

Although  this  description  and  the  measurements  refer  specially  to  the 
Melicerta  rhigens,  yet  the  relatively  large  size  of  the  cells  is  a  feature  com- 
mon to  all  the  Rotatoria,  and  has  been  pointed  out  and  figured  by  Leydig, 
Siebold,  and  others. 

The  second  stomach,  noticed  by  Williamson  in  Melicerta,  also  had  a  layer  of 
epithelial  cells  bearing  cilia  "  even  longer  than  those  of  the  upper  viscus, 
— although  the  paiietes  were  very  much  thinner  and  more  transparent,  the 
cells  being  less  easily  traced."  In  the  third  or  lowest  dilatation,  seen  by 
Huxley  in  LacinuJaria,  the  interior  was  clothed  with  very  long  cilia  (XL.  4). 

Ehrenberg  remarked  the  existence  of  large  stomach- cells  in  Diglena  la- 
custris,  and  of  less  distinct  ones  in  Notommata  Myrmeleo  and  N.  Copeus.  The 
pouches  he  speaks  of  around  the  alimentary  tube  of  Hydatina  senta,  and 
which  imparted  the  appearance,  to  Ms  eye,  of  a  bunch  of  grapes,  are  no  other 
than  epithelial  cells.  In  Philodincea  the  intestinal  canal  is  stated  to  be  fili- 
form, and  enveloped  in  a  granular  cellular  mass  ;  that  is  to  say,  the  calibre  is 
very  much  reduced  by  the  tiu'gid  cells  lining  the  walls.  The  compact  mass 
of  blind  tubules,  so  described  in  Eotifer,  admits  a  like  interpretation. 

In  Notommata  tardigrada  Leydig  failed  to  detect  cilia  either  in  the  stomach 
or  intestine. 

In  the  great  majority  of  the  Rotatoria  a  definite  ^'  intestine  "  follows  the 
stomach,  and  ends  below  in  the  cloaca.  This  intestine  is  generally  known  as 
the  "  rectum,''^  and  is  supposed  to  represent  the  large  intestine  of  higher  ani- 
mals. It  varies  much  in  its  dimensions  in  different  species,  especially  in  its 
length  and  course.  It  is  long,  straight,  and  capacious  in  Notommata  centrura 
(XXXYIII.  26),  and  in  Euchlanis  triquet7'a  (XXJLYIII.  5),  short  in  Lacinu- 
laria,  and  extremely  short  in  Notommata  tardigrada. 

Among  the  encased  Rotatoria  it  is  of  considerable  length,  owing  to  its 
curving  forwards  from  the  second  stomach,  so  as  to  reach  its  outlet  near  the 
margin  of  the  enclosing  urceolus,  or  in  other  words  the  neck  of  the  animal, 
and  thereby  provide  for  the  immediate  removal  of  the  excrementitious  matter 
from  contiguity  with  it  (XXXYII.  17).  In  Stephanoceros  and  Floscidaria,  as 
exceptions  to  this  rule,  this  intestine  is  short.  Looking  at  the  so-caUed  second 
stomach,  placed  at  the  head  of  the  rectum  in  these  fixed  Rotifers,  we  might 
rather  assimilate  it  to  the  caecum,  wliich  in  some  of  the  higher  classes  forms 

2e2 


420  GENERAL  HISTORY  OF  THE  INFrSORlA. 

a  sort  of  subsidiary  stomach,  where  the  digestive  process  is  finally  completed. 
Still  it  is  not  possible  to  establish  all  the  minute  homological  relations  be- 
tween these  animals  and  those  of  the  vertebrate  class.  The  intestine,  like 
the  stomach,  has  a  limiting  membrane,  possibly  muscular,  and  is  lined  by  a 
ciliated  epithelium  which,  unlike  that  of  the  stomach,  is  not  coloured,  and 
its  cells  less  easily  detected.  It  is  capable  of  very  great  distension.  The 
rectum  commonly  ends  in,  or,  it  may  be  said,  expands  into,  a  globular  sac, 
which,  from  its  likewise  receiving  the  eggs  from  the  0"sdducts  opening  into  it, 
is  analogous  to  the  cloaca  of  birds  (XXXYIII.  26  i).  This  cloaca  has  a 
fine,  transparent  wall,  and  opens,  posteriorly  or  dorsally,  at  the  base  of  the 
pseudopodium,  or,  where  this  segment  is  absent,  near  the  extremity  of  the 
body,  by  an  outlet  usually  called  the  anus. 

The  cloaca  is  particularly  dilatable ;  for  sometimes  it  is  much  loaded  with 
accumulated  faecal  matter,  and  at  others  is  distended  by  one  or  more  of  the 
enormous  eggs  the  Rotatoria  habitually  produce.  In  discharging  an  egg,  or 
in  emptying  itself  of  other  matters,  the  cloaca  is  everted  and  thrust  out 
through  its  external  orifice. 

From  the  mode  in  which  the  walls  are  drawn  into  longitudinal  and  circular 
folds,  as  exemplified  in  Nofommata  cenfrura  (XXXVIII.  26),  Leydig  is  in- 
duced to  admit  the  presence  of  muscular  fibrils  regularly  disposed  in  the 
two  corresponding  directions.  Moreover  the  manner  in  Avhich  the  cloacal 
orifice  is  closed,  after  the  extrusion  of  any  mass,  indicates,  in  this  author's 
opinion,  a  sjDhincter  power,  and  consequently  the  presence  of  muscular  fibres 
around  it.  The  contraction  of  the  entire  canal  on  itself  is  sometimes  so  great 
that  it  is  only  manifest  by  a  streak. 

A  most  remarkable  structural  exception  is  met  with  among  certain  female 
Rotatoria,  viz.  the  entire  absence  of  an  intestine  and  anus.  It  prevails  in 
the  genus  Asplanchna  (Gosse),  in  the  Notommata  SieholdU  (Leydig)  (probably 
in  N.  Syrinx),  in  Ascomorpha  Helvetica  (Periy),  and  in  A.  Germanica  (Perty) 
(XXXYI.  9  ;  XXXVII.  32 ;  XXXYIII.  28).  This  want  of  a  discharging 
posterior  outlet  necessitates  the  rejection  of  excrementitious  matters  from  the 
stomach  through  the  mouth. 

This  structure  is  so  very  exceptional  and  peculiar,  that  Prof.  "Williamson 
is  not  prepared,  without  further  evidence  than  has  yet  been  advanced,  to 
admit  it  as  time  of  any  Rotifera.  It  is,  he  writes  {in  lit.)  contraiy  to  pro- 
bability, and,  if  established,  would  induce  him  to  exclude  the  animals  so 
organized  from  that  class. 

Reception  of  Food — its  Deglutition,  &c. — The  food  of  the  Rotatoria,  as 
before  noticed,  is  attracted  towards  the  mouth  by  the  vortex  caused  by  the 
rotation  of  the  cilia  crowning  the  head.  An  exceptional  means  of  prehension 
is  seen  in  those  Rotatoria  which  protrude  their  jaws  beyond  the  mouth,  using 
them  as  pincers  or  forceps  to  seize  any  larger  prey.  ^'  In  general,"  wiites 
Mr.  Gosse  {Phil.  Trans.  1856,  p.  429),  "  the  ciliaiy  vortices  are  sufiicient  to 
bring  the  prey  Tsithin  the  buccal  funnel  (pharynx)  ;  but  in  several  genera 
of  the  family  Euchlanidota,  as  Metopidia,  Colunis,  Monura,  and  Steplianops, 
there  is  a  curious  accessory  organ,  which  aids  in  the  captui'e  of  the  prey ;  at 
least  I  am  sure  it  is  so  employed  in  several  species  of  Metopidia.  Thus  in 
M.  acuminata  the  frontal  region  is  formed  by  an  arched  fleshy  process  occi- 
pitally,  which  is  approached  by  a  small  one  on  the  '  mental '  side  ;  and  be- 
tween these  is  the  wide  entrance  of  the  buccal  funnel.  The  occipital  process 
is  protected  by  a  horny  crystalline  plate,  forming  a  segment  of  a  sphere,  and, 
when  viewed  laterally,  taking  the  appearance  of  a  curved  horn.  It  can  be 
partially  protruded  and  retracted,  and  also  bent  do^Ti  to  meet  the  mental 
lobe.     This  apparatus,  when  the  animal  is  taking  food,  is  kept  in  vigorous 


OF  THE  ROTATORLi.  421 

action.  A  strong  vortex  is  produced  by  the  ciliary  wheels ;  and  as  the 
floating  atoms  whirl  by,  the  moveable  plate  is  thrown  forward  with  a  grasp- 
ing motion,  the  fleshy  head  being  at  the  same  time  protnided,  and,  when 
the  lobes  are  in  contact,  retracted.  This  is  repeated  almost  every  instant 
with  manifest  eagerness  and  discrimination,  the  manducatory  apparatus 
working  vigorously  all  the  while. 

"  The  same  curious  organ  is  frequently  employed  in  another  way.  It  is 
bent  considerably  downward ;  and  as  the  animal  crawls  deliberately  up  and 
down  the  stems  of  aquatic  plants,  it  is  used  to  rake  and  grub,  among  the 
floccose  deposits,  the  minute  Diatomacece,  &c.,  that  adhere  to  them." 

Having  entered  the  mouth,  it  is  usually  rapidly  conveyed  along  the  pharynx 
to  the  jaws.  In  those  species  which  have  the  pharynx  expanded  into  a  ^'  crop," 
such  as  Floscularia  and  AspJancha,  this  transmission  of  the  food  is  less  speedy. 
Mr.  Gosse  imagines  the  ''  crop  "  to  possess  a  suctorial  power.  He  says — 
"I  think  that  when  the  animal  {AsplancJina priodonta)  is  cognizant  of  food 
brought  to  the  mouth  by  the  ciliary  vortices,  it  suddenly  expands  the  crop  by 
the  action  of  the  muscles  that  go  from  it  to  the  skin,  when  the  water  rushing 
into  the  vacuum  carries  in  the  prey.  Then  the  network  of  fibres  contracts 
again,  and  the  prey  is  secui'ed," 

Having  reached  the  ''  maxillary  head,"  th€  food  is  "  lodged "  (to  quote 
Mr.  Gosse's  paper)  "  upon  the  *  rami '  between  the  two  '  unci.'  These  con- 
jointly work  upon  the  food,  which  passes  on  towards  the  tips  of  the  '  rami,' 
and  enters  the  oesophagus  (the  proventricular  tube),  which  opens  immediately 
beneath  them." 

Having  escaped  the  mandibular  apparatus,  the  food  is  subjected  to  the 
action  of  some  digestive  fluids  which  are  poured  into  the  portion  of  the  ali- 
mentary tube  below,  whether  that  portion  be  dilated  into  a  distinct  stomach, 
or  retain  a  nearly  imiform  calibre.  How  long  this  process  of  digestion  need 
be  continued,  we  have  no  data  to  determine ;  but  we  may  conclude  that  the 
time  will  varj^  according  to  the  nature  of  the  food,  the  condition  of  the  animal, 
its  species,  and  other  circumstances.  In  Melicerta  rhigens,  which  has  a  double 
stomach.  Prof.  Williamson  remarks  that  the  upper  one  "  appears  to  be  chiefly 
a  receptacle  for  the  food.  From  time  to  time,  especially  w^hen  the  \iscus  is 
distended,  a  portion  of  its  contents  pass  down  into  the  lower  stomach."  In 
this  the  mass  of  food  usually  distending  it  "  is  constantly  revohdng, — the 
motion  being  due  to  ciliary  action.  This  process  goes  on  for  some  minutes, 
after  which  the  creature  contracts  its  body,  and  forces  the  entire  exuvige  out 
of  the  viscus  into  a  long  narrow  cloaca  (rectum),  which  terminates  externally 
by  an  anal  outlet.  As  it  does  this,  it  everts  a  considerable  portion  of  the 
cloaca,  thus  almost  bringing  the  cloacal  outlet  of  the  stomach  to  the  exterior, 
and  causing,  at  the  same  time,  a  large  transparent  protuberance  to  be  deve- 
loped on  the  coiTcsponding  side  of  its  body.  At  other  times  the  creatui^e  can 
draw  in  these  appendages,  so  that  scarcely  any  trace  of  a  cloacal  canal  is  visi- 
ble." Mr.  Gosse  suggests  that  this  protrusion,  at  the  moment  of  discharge, 
is  designed  "  to  shoot  the  faecal  mass  out  of  the  case  "  (urceolus) ;  for  the 
outlet  is  then  projected  above  the  rim.  "  The  faeces,"  he  adds,  "  are  slightly 
coherent  and  jelly-like,  not  at  aU  like  the  coloui'ed  pellets  of  which  the  urce- 
olus is  built  up." 

The  food  of  the  Eotatoria  consists  of  the  lower  Algae,  of  Protozoa,  Ento- 
mostraca,  other  Rotifers,  and  even  the  weaker  members  of  the  same  species. 
"  The  stomach,"  remarks  Mr.  Gosse,  "  of  the  As])lanchna  is  frequently  occu- 
pied with  animals ;  the  smaller  Anurcece,  as  A.  aculeata,  A.  curvicornis  (?), 
and  A.  stipitata  (?),  seem  to  constitute  its  chief  food.  I  have  taken  one  with 
the  species  last-named  in  its  stomach,  which,  after  about  an  hoiu',  was  ejected 


422  GENERAL  HISTORY  OF  THE  INFUSORIA. 

and  swam  about  as  lively  and  apparently  uninjured  as  ever.  In  one  I  saw 
several  specimens  of  a  long  slender  Fragilaria  hose  in  the  cavity  of  the  body, 
and  in  the  stomach  of  another  the  long  cell  of  a  Conferva." 

From  the  manner  in  which  the  food  is  obtained,  apparently  without  any 
selection  on  the  part  of  the  animals,  the  vortex  driving  into  the  mouth  what- 
ever particles  may  come  within  its  reach,  we  might  conclude  that  the  con- 
tents of  the  stomach  must  be  of  a  very  miscellaneous  character.  This  is  true 
to  a  great  extent ;  yet  the  Rotifers  can  eject  what  is  unsuitable,  and  they 
have  the  power  of  moving  from  place  to  place  in  search  of  suitable  nutri- 
ment, or  at  least,  as  in  the  fixed  forms,  of  arresting  and  withdi^a^ving  the 
ciliary  apparatus  until  noxious  materials  are  floated  past,  or  appropriate  ones 
have  come  vrithin  reach.  That  they  are  passive  recipients  of  the  cuiTent 
setting  into  their  mouths,  is  indicated  by  their  swallowing  carmine  or  other 
colouring  matters  mixed  with  the  water,  which,  as  Mr.  Gosse  observes,  are 
deleterious  to  them. 

The  feeding  of  Rotatoria  with  colouring  matter  serves  a  practical  purpose 
in  the  examination  of  their  structure  ;  for  it  helps  to  reveal,  by  the  contrast 
of  coloured  with  uncoloured  parts,  details  of  structure  not  apparent  amid  the 
uniform  and  dehcate  hue  of  the  entire  organism  in  its  natural  state.  For 
example,  Mr.  Gosse  writes — "  The  process  of  swallowing  carmine  enabled 
me  to  see  (in  Melicerta),  very  distinctly,  that  the  oesophagus  enters  the  giz- 
zard between  the  larger  ends  of  the  jaw-mullers,  and  that  the  stomach-duct 
leads  off  from  their  smaller  ends  through  the  semiglobular  lobe  beneath." 
The  same  observer  employed  this  means  to  demonstrate  the  manner  in  which 
the  case  of  the  AleUcerta  is  deposited,  and  with  very  satisfactory  results 
(see  p.  425). 

The  Secreting  System. — Special  organs  of  secretion  exhibit  themselves  in 
the  Rotatoria  under  the  simplest  form  of  cells,  and  of  involutions  of  the  lining 
membrane  of  the  alimentary  tube,  as  sacs  and  tubules.  Frequently  their 
contents  are  coloiu^ed ;  and  these  always  differ  in  density  and  physical  ap- 
pearance from  the  general  fluids  of  the  body.  The  glandular  organs  situated 
about  the  walls  of  the  digestive  canal,  are  supposed  to  have  discharging  ducts 
thi'ough  which  their  contents  percolate  into  that  tube. 

The  testes  or  spermatic  glands  in  the  male,  and  the  ovary  in  the  female — 
both  of  them  secreting  organs, — together  with  some  accessory  secerning  vesi- 
cles, will  be  described  under  the  section  on  the  Reproductive  Organs.  Some- 
thing has  already  been  said  of  some  other  glands  in  the  last  section,  on  the 
Digestive  Organs  :  a  more  precise  account  is,  however,  necessary. 

The  most  constant  glands  are  the  two  situated  on  the  upper  surface  of  the 
stomach  near  the  entrance  of  the  gastric  or  proventricular  tube,  and  some- 
times on  that  tube  itself  (XXXVIII.  2Q  h,  271).  They  are  usually  hemi- 
spherical or  oval,  but  assume  other  shapes,  as  pyriform,  conical,  cyhndrical, 
reniform,  crescentic,  and  forked.  In  a  few,  e.  g.  Noteus  and  some  Brachioncm, 
they  are  stalked,  or,  more  properly  speaking,  have  an  elongated,  tapering  ex- 
tremity. Cylindrical  or  club-shaped  glands  are  seen  in  Notommata  clavulata, 
and  forked  ones  in  Diglena  lamistris.  In  these  two  species,  and  also  in  3Ie- 
galotrocha  there  are  likewise  foiu*  long  filiform  tubes,  equalling  the  glands  in 
length,  and  of  the  like  coloiu%  but  opening  at  the  centre  instead  of  the  fore- 
part of  the  stomach.  In  Polyarthra,  Leydig  noticed  two  elongated  secreting- 
sacs  attached  to  the  jposterior  surface,  and  in  Lacinularia,  a  pair  of  glands, 
instead  of  a  single  one,  at  the  fore  part  of  the  stomach.  J^ot  being  able 
to  detect  the  ducts  of  the  ^'  2-3  pyriform  glandular  (?)  -looking  bodies  often 
attached  to  the  base  of  the  upper  stomach  (of  Melicerta)  near  the  constriction 
which  separates  it  from  the  lower  one,  Prof.  Williamson  hesitates  to  call 


OF  THE  EOTATOEIA.  423 

them  glands,  and  doubts  likewise  the  secretory  character  of  the  similar  but 
larger  bodies  seen  in  the  neighbourhood  of  the  oesophagus." 

The  glands  are  usually  transparent,  or  have  only  a  slight  milky  opacity ; 
they  contain  fine  nucleated  granules  and  molecules,  and  in  some  examples, 
e.  g.  Polyarthra  (XXXVIII.  39)  and  Pterodina,  a  few  small  oil  vesicles. 
Externally  they  are  invested  by  a  transparent  homogeneous  membrane,  to 
which,  in  Alhertia,  Dujardin  assigned  an  active  contractility ;  but  this  is  very 
doubtful.  ''  They  are,"  says  the  French  naturahst,  "  stalled  sacs,  placed  at 
the  commencement  of  the  intestine,  susceptible  of  contraction,  pouring  out 
their  secretion  into  the  intestine,  from  which  they  again  fill  themselves,  and 
undergo  dilatation  :  in  this  example  at  least,  these  appendages  must  be  con- 
sidered caeca  rather  than  glands."  ''  Sometimes,"  Leydig  observes,  "  the 
elements  of  the  contained  granular  mass  have  an  elongated  figure,  as  in  No- 
tms;  and  then  the  contents  of  the  glands  assume  a  striated  appearance." 
This  account  recalls  that  given  by  Mr.  Williamson  of  a  glandular  structure 
he  supposes  may  possibly  represent  a  spermatic  gland  ;  but  of  this  hereafter. 
Cohn  believes  he  detected  the  exudation  of  a  blackish  granular  fluid  fi'om 
these  glands  in  Hydatina  senta,  and  its  entrance  within  the  stomach  by  a 
definite  apertiu-e.  . 

The  granular  vesicles  of  the  glands  were  termed  "  vacuoles  "  by  Dujardin, 
and  have  been  represented  by  Ehrenberg  in  many  figures,  e.  g.  of  Euchlanis 
macrura,  E.  dilatata,  Megcdotrocha,  and  Lacimdaria ;  they  have  also  been 
spoken  of  by  him  as  "  glands,  vesicular  within."  Moreover  the  shai-ply- 
defined  clear  vesicles  he  has  represented  in  Theorus  (XXXIY.  427-429)  and 
Pterodina,  and  termed  "  eyes,"  Leydig  believes  to  be  notliing  else  than  fat- 
vesicles  of  the  gastric  glands.  Mr.  Dahymple  has  accurately  figured  these 
glands  in  his  so-called  Notommata  {AsplancJma)  Anglica  (XXXVI.  9  g). 

The  function  and  homologies  of  these  gastric  glands  are  doubtful.  Ehren- 
berg's  first  notion  of  them  was  that  they  were  spermatic  ;  but  he  subsequently 
changed  his  \'iews,  and  called  them  ''  pancreatic."  ^'  For  what  reason,"  says 
Prof.  Rymer  Jones,  "  Ehrenberg  has  given  the  name  of  pancreas  to  these  se- 
creting ca^ca,  it  is  difficult  to  conjecture,  since  the  first  rudiments  of  a  pan- 
creas are  only  met  mth  in  animals  far  higher  in  the  scale  of  animal  existence ; 
ever}^  analogy,  indeed,  would  lead  us  to  denominate  these  caeca  the  fii'st  ru- 
diments of  a  liver,  by  far  the  most  important  and  universal  of  the  glandular 
organs  subservient  to  digestion,  and  in  a  variety  of  creatiu-es  presenting  an 
equal  simplicity  of  structure." 

However  unsupported  the  notion  of  the  pancreatic  or  saKvary  nature  of 
these  glands  may  be,  it  has  met  with  several  advocates,  who  have  in  all  pro- 
bability assigned  to  them  this  function  rather  from  the  want  on  their  part  of 
any  definite  opinion  of  their  character  than  for  any  other  reason.  Thus  Dal- 
rjTuple  alludes  to  them  as  salivary  glands  ;  and  Perty  affirms  of  two  filiform 
vesscl-hke  appendices  of  the  stomach  (?)  in  Enteroplea,  that  they  are  repre- 
sentatives of  the  pancreas  or  of  salivary  glands.  Siebold  adopted  a  similar 
hypothesis ;  but  Leydig,  on  the  contrary,  regards  them,  in  a  morphological 
pomt  of  view,  not  as  pancreatic  glands,  but  as  the  analogues  of  those  pro- 
cesses often  seen  on  the  stomach  of  ArthroiJoda  ;  he  would  therefore  desig- 
nate them  generally  gastric  glands, — a  view  with  which  we  are  disposed  to 
coincide.  The  small  glandular  appendages  on  the  dorsal  sm^face  of  the  sto- 
machs of  starfish,  suggest  themselves  as  of  the  same  natin-e  as  the  appendages 
under  consideration. 

A  yellowish  clear  body  is  situated  on  each  side  of  the  pharynx,  imme- 
diately in  front  of  the  maxillary  bulb,  in  Lacimdaria,  Tubicolaria,  Melicerta, 
and  Brachionv.s  (XXXIX.  16),  and  rather  within  the  substance  of  the  bulb 


424  GENERAL  HISTORY  OF  THE  INFUSORIA. 

in  Noteus.  This  is  possibly  the  structure  alluded  to  by  Mr.  Gosse  as  "  several 
yellow  glandular  (?)  spots  "  seated  on  the  top  of  the  cushion  of  the  dental 
organs  of  Asplanchna  (XXXVIII.  28),  and  the  same  with  the  yellowish, 
clear,  horny-looking  masses  mentioned  by  Huxley  va.  Lacinularia  (XXXVII. 
19  ^)  and  Bracliionus.  The  last-named  natui'alist  refers  these  bodies  to  the 
*'  homy  skeleton  "  (see  p.  412).  Leydig  considered  they  might  possibly  be 
"  saHvary  glands." 

The  epithelium  of  the  aUmentarj^  canal  has  probably  a  glandular  purpose  : 
its  large  cells  are  filled  with  a  granular  matter,  and  many  oil-vesicles,  besides 
a  nucleus.  The  number  and  large  size  of  these  gastric  cells  have  been  already 
illustrated  (see  p.  419) ;  they  are  mostly  coloured — yellow  or  yellowish  brown, 
with  sometimes  green  spots  interspei-sed.  Ehrenberg  remarked  these  ceUular 
accumulations,  and  advanced  the  hypothesis  of  their  homology  with  the  liver 
of  higher  animals.  The  colouring  matter  was  consequently  esteemed  to  be 
the  bile.  We  have  seen  that  Rymer  Jones  has  assigned  the  fimctions  of  a 
liver  to  the  so-called  ''  pancreatic  "  sacs,  or  "  gastric  glands."  However, 
most  naturalists  favour  Ehrenberg's  view ;  among  them  are  Dujardin,  Sie- 
bold,  Leydig,  and  Dairy mple.  The  belief,  indeed,  of  the  great  Berlin  natu- 
ralist was,  that  the  ceUs  grew  from  the  exterior  of  the  wall  of  the  alimentary 
canal,  and  were  so  many  saccular  appendages ;  this  view  modern  research 
does  not  countenance,  but  affirms  the  presence  of  the  ceUs  within  the  canal. 
The  examples  of  secerning  cells  given  by  Ehrenberg  deserve  to  be  mentioned. 
He  remarked  that  in  Enteroj^lea  the  biliary  cells  and  ducts  were  most  pro- 
nounced, and  that  there  was  great  accumulation  of  cellular  or  glandular  ele- 
ments about  the  intestine  of  Rotifer,  CalUdhm,  and  Philodina ;  in  the  last 
two  he  also  asserted  that  the  mass  becomes  coloured  by  colouring  particles 
swallowed  by  the  animals. 

Mr.  Gosse  puts  the  question  whether  the  little  granular  body  near  the 
tip  of  the  pedicle  of  Melicerta  is  a  secerning  gland  for  the  secretion  of  an 
adhesive  glue,  by  which  the  foot  adheres,  as  in  Monocerca.  This  faculty 
of  secreting  an  adhesive  matter  from  the  end  of  the  pseudopodium  is  sur- 
mised by  Perty  to  be  possessed  by  several  Rotatoria,  viz.  by  ConocMlus,  La- 
cinularia, (Ecistes,  Floscidaria,  Limnias,  Tuhicolaria,  and  Stephanoceros. 
This  idea  is  countenanced  by  Cohn  (Zeitschr.  1855,  p.  439),  who  inclines  to 
the  belief  that  the  solid-lookmg  elongated- oval  bodies  situated  at  the  poste- 
rior extremity  of  the  abdomen  of  Bracliionus  and  other  species,  and  usually 
considered  muscular  (moving  the  tail-process),  are  rather  of  a  glandular  na- 
ture, and  possibly  secrete  an  adhesive  glue  to  fix  the  animal.  More  recently 
(Midler's  ArcMv,  1857,  and  A.  N.  H.  1857,  xx.  p.  292)  Leydig  has  accepted 
this  view,  and  thus  treats  of  these  structures  in  Hydatina  senta  : — "  The 
clavate  bodies  in  the  tail  consist  of  a  delicate  envelope  and  pale  molecular 
contents,  in  which  beautiful  nuclei,  each  with  a  nucleolus,  may  be  distin- 
guished ;  in  many  individuals,  small  fatty  points  are  also  present  in  variable 
amount.  I  regard  the  organs  in  question  as  glands,  which  in  their  position 
and  fimction  correspond  with  the  caudal  glands  of  Enoplus  for  examj)le ;  they 
open  at  the  apex  of  the  caudal  appendages  (Fiisszangen) ;  and  as  the  worm 
just  mentioned  '  can  attach  itself  firmly  to  the  object-bearer  by  the  posterior 
extremity  of  the  body,  in  order  to  carry  the  body  round  this  point  with  a  waving 
motion,'  so  also  can  the  Hydatina  fix  itself  by  the  tips  of  the  caudal  append- 
ages, probably  by  means  of  the  sticky  substance  excreted  here.  It  seems  to 
me  also,  that  in  a  certain  upright  position  of  the  caudal  appendages,  I  have 
detected  the  opening  at  their  tip." 

Other  large  vesicles,  which  some  think  may  be  glandular,  occur  in  different 
parts  of  the  body,  and  in  the  foot- process  of  several  genera.    Such  are  noticed 


OF  THE  ROTATORIA.  425 

by  Dobie  in  the  pseudopodiiim  of  Floscularia ;  and  Leydig  mentions  a  clear 
gland  or  space  at  the  root  of  the  tail  of  Lacinidaria,  from  which  he  supposes 
a  duct  to  extend  to  the  extremity ;  such  a  structure  Huxley  cannot  discover, 
but  states  that  the  extremity  of  the  tail  always  seemed  to  him  "  to  present 
a  ciliated  hemispherical  cavity,  closed  above ;"  the  supposed  gland  at  the  base 
he  called  a  "  vascular  mass." 

An  active  secreting  power  is  displayed  by  those  Rotatoria  which  invest 
themselves  in  cases  or  urceoli ;  for  such  cases  are  always  produced  fi'om  the 
animal,  and  are  the  result  of  excretion.  The  formation  of  its  case  by  the  Meli- 
certa  ringens  has  often  been  most  thoroughly  examined ;  and  Mr.  Gosse  was 
enabled  to  watch  the  deposition  of  pellet  by  pellet  of  the  excreted  matter. 
This  direct  observation  has  entirely  overthrown  the  prevalent  notion  first  ad- 
vanced by  Ehrenberg,  that  the  case  was  built  up  of  excrementitious  particles 
discharged  from  the  alimentary  canal.  The  organ  actively  engaged  in  the 
building  of  the  case  is  seated  immediately  above  the  long  tubular  process 
extending  from  the  neck  of  the  animal  (XXXYI.  1  c) ;  it  is  cup-shaped, 
and  its  concave  sirrface  so  ciliated,  that  when  in  full  activity  it  seems 
to  revolve.  In  this,  which  Mr.  Gosse  calls  the  ^^ pellet-cup, ^^  the  building- 
material  seems  to  be  prepared  and  fashioned  into  an  oval  or  hexagonal  figure, 
and  then  the  pellets  so  moulded  are  regularly  laid  down  in  rows,  "  straight 
and  uninterrupted  perpendicularly,"  but  zigzag  transversely,  so  that  a  dia- 
gonal disposition  is  the  result.  "  Each  peUet,  examined  separately,  is  of  a 
yellowish  or  olive  colour,  composed  of  granules  ;  the  whole  tube  is  of  a  red- 
dish-brown (XXXYI.  1  d).  After  a  certain  number  were  deposited  in  one 
part,  the  animal  would  suddenly  turn  itself  round  in  its  case,  and  deposit 
some  in  another  part."  It  seems  that  the  action  of  the  pellet-cup  is  volun- 
tary, and  not  always  coexistent  with  the  passing  of  the  ciliary  current  over 
the  chin.  The  animal  frequently  makes  abortive  efforts  to  deposit  a  pellet, 
and  sometimes  bends  forcibly  forward  to  the  edge  of  the  case  before  the  pellet 
is  half  formed.  Coloiu-ed  particles  in  the  water  are  hurled  round  the  margin 
of  the  ciliated  disk  until  they  pass  off  in  front  through  the  great  sinus  be- 
tween the  large  petals ;  and  the  atoms,  if  few,  glide  along  the  facial  surface, 
following  the  irregularities  of  the  outline  with  great  precision,  and,  dashing 
round  the  projecting  chin,  lodge  themselves  one  after  another  in  the  little 
cup-like  receptacle  beneath,  in  which  they  are  whorled  round  with  great 
rapidity,  and  prepared  into  pellets  for  the  construction  of  the  case.  On  mix- 
ing carmine  with  the  water,  the  torrent  that  poured  off  in  front  and  the  ap- 
pearance of  a  rich  crimson  pellet  in  the  cup  were  instantaneous.  A  large 
animal  which  had  its  case  accidentally  slit  for  some  distance,  watched  for 
several  days,  was  seen  to  make  pellets  frequently ;  yet  it  never  deposited  them 
nor  attempted  to  construct  a  new  case,  but  let  the  pellets  float  away." 

Such  is  a  resume  of  Mr.  Gosse's  interesting  observations.  Prof.  Williamson 
adds  that,  when  the  animal  is  not  engaged  in  its  architectural  occupations, 
the  sac  (pellet- cup)  becomes  so  contracted  as  to  be  almost  invisible. 

In  connection  with  this  subject  of  secretion,  must  be  mentioned  the  views 
of  Leydig  respecting  the  accumulation  of  granules  or  crystalline  particles 
seen  in  many  embryonic  and  young  Rotatoria,  enclosed  in  a  sac  contiguous 
to  the  cloaca  (XXXYII.  4;  XXXYIII.  7,  8).  Ehrenberg  remarked  these 
granular  heaps  in  Microcodon,  Lacinularia,  StepJianoceros,  Floscularia  ornata, 
Enteroplea,  and  in  Notommata  granulans,  and  called  them  at  one  time  "  a 
dark  glandular  body  or  speck,"  at  another  "  a  single  glandular  organ  "  having 
no  evident  function.  Weisse  represented  them  to  be  unconsumed  and 
stiU-remaining  yelk- substance,  and  supposed  the  animals  presenting  such 
granular  masses  '^  premature  "  or  "  aborted."     Williamson  noticed  similar 


426  GENEEIL  HISTOEY  OF  THE  INFIJSOllIA. 

masses  in  Melicerta,  and  found  that  they  disappeared  soon  after  the  young 
animal  escaped  from  the  o\a.im. 

Leydig's  conclusion,  from  optical  and  chemical  qualities  of  the  granules,  is 
that  they  are  uiinary  or  mic  concretions,  and  that  the  clear  space  containing 
them  is  formed  by  the  end  of  the  intestinal  canal,  or  by  the  cloaca.  To 
elucidate  this  view,  an  analogy  is  pointed  out  in  the  case  of  those  insects 
which  undergo  complete  metamorphosis,  in  which  solid  urinary  concretions 
accumulate  in  the  rectum  during  the  pupa-state,  but  are  evacuated  when  the 
insect  emerges  from  that  torpid  condition. 

The  actual  secreting  organ  of  these  urinary  concretions,  or  in  other  words 
the  kidney,  must,  says  Leydig,  be  sought  for  in  the  cells  of  the  intestinal 
wall,  which  stand  out  in  a  knob-like  matter.  Ehrenberg's  account  of  the 
"  dark  bodies  "  about  the  rectum  of  Enteroplea,  and  of  Notommata  granulans, 
favours  this  opinion  ;  and  the  granular  heap  near  the  termination  of  the 
intestine  of  the  larva  of  Cydojps  may  be  adduced  as  another  allied  fact  in 
illustration  of  the  nature  of  the  bodies  in  question.  Yogt,  however,  is  opposed 
to  this  presumed  analogy,  and  states  that  this  peculiar  collection  in  the  cloaca 
of  embiyo  Cyclopes  is  originally  produced  of  a  green  colour,  within  a  sac  on 
each  side  of  the  intestine,  and  when  subsequently  discharged  into  the  cloaca, 
is  of  a  yellow  hue.  These  sacs  therefore  have,  in  his  estimation,  rather  the 
signification  of  a  liver  than  a  kidney.  The  like  stnictures  are  common  enough 
in  Vermes.  Exceptiilg  therefore,  Leydig  contends,  male  Rotifers,  urinary 
concretions  occur  only  in  the  embryo  and  in  the  first  period  after  birth,  and 
the  existence  of  a  primordial  kidney  must  be  admitted  as  a  fact.  Cohn  has 
come  forward  to  oppose  these  views  of  Leydig,  and  says  that  this  whole  hy- 
pothesis falls  with  the  proof  that  in  Enteroplea  the  vesicle  with  the  dark 
granules  stands  in  no  sort  of  connexion  with  the  intestine,  nor,  indeed,  can 
do  so,  as  no  intestine  exists,  and  it  is  rather  firmly  adherent  to  the  outer  wall 
of  the  testis.  To  this  adverse  oj)Lnion  Leydig  rejoins  (Miiller's  Arcliiv,  1857, 
p.  404,  and  A.  N.  H.  1857,  xx.  p.  295)  that  Cohn's  "  undoubted  proof"  is 
itself  an  error ;  "  for  the  clear  space  containing  the  dark  granules  is  not  ad- 
herent to  the  true  wall  of  the  testis,  but  to  that  outer  envelope  which  repre- 
sents the  rudimentary  stomach  and  intestine ;  or,  more  properly  spealdng,  the 
clear  space  enclosing  the  concretion  belongs  to  the  abortive  alimentary  canal 
itself,  which  extends  from  the  notch  of  the  rotary  organ  to  the  cloacal  open- 
ing, so  that  Enterop>lea  displays  the  same  characters  as  the  other  Eotatoria, 
although  this  is  in  complete  opposition  to  the  description  given  by  Cohn.  My 
opinion,  that  the  granules  in  question  are  uric  concretions,  is,  of  course,  no 
more  strongly  supported  by  the  position  of  matters  detected  in  Enteroplea 
than  before  ;  but  the  objection  raised  by  Cohn  appears  to  be  removed.  The 
opinion  first  put  forward  by  Weisse,  which  is  also  favoured  by  Cohn,  that  the 
granules  are  the  remains  of  unused  yelk-masses,  I  must  reject,  without  taking 
other  reasons  into  account,  Lf  only  because  the  vitelline  elements  and  the 
granules  in  question  have  no  resemblance  to  each  other,  but  are  perfectly 
different  things." 

Several  authors  have  suggested  that  the  vascular  apparatus  to  be  described 
as  a  respiratory  organ  in  the  foILovving  chapter  has  also  in  part,  or  even 
principally,  the  fimction  of  a  kidney  or  excretory  organ.  These  views  can 
be  best  propounded  after  the  apparatus  in  question  has  been  described. 

The  Yascular  and  Eespihatoey  Systems  (XXXVIII.  26  e,  i,  I ;  XL.  1  ?',  5). 
— ^The  existence  of  vessels  subservient  to  the  circulation  of  a  fluid  analogous 
to  blood  was  surmised  by  Ehi'enberg.  Among  such  assumed  structures  were 
the  transverse  cords  to  which  the  semblance  of  articulation  is  often  due, 
as  well  as  other  similar  bands  now  proved  to  be  muscular  fibres  of  con- 


OF  THE  ROTATOUIA.  427 

nective  tissue.  For  instance,  the  intercurrent  fibres  about  the  head  and  neck 
of  the  Eotatoria,  and  the  interlacing  cords  passing  forward  to  the  lobes  of 
the  rotary  organ,  and  backward  to  the  maxillarj  head,  were  reckoned  parts 
of  the  vascular  system. 

The  purpose  of  a  circulatory  system  is  to  convey  the  blood  (the  nutritive, 
reparative  fluid)  within  the  reach  of  every  tissue  and  organ,  so  that  all  its 
parts  may  be  renovated,  and  their  effete,  worn-out  particles  removed.  The 
necessity  for  such  a  contrivance  is  at  once  intelligible  in  large  animals,  where 
the  parts  have  considerable  size  and  thickness,  and  are  pretty  closely  packed 
within  the  limits  of  the  body ;  but  in  the  case  of  the  Rotifers,  the  proto- 
plasmic fluid  fills  up  all  the  large  space  within  the  body  unoccupied  by  the 
\dscera,  and  is  in  immediate  contact  with  them,  whilst  none  of  them  have 
such  a  density  or  thickness  as  to  preclude  their  being  readily  permeated  by 
it.  The  result  of  digestion  within  the  ahmentary  canal  is  the  production  of 
a  nutritive  juice  or  chyle,  which  apparently  passes  by  exosmosis  through  the 
walls  of  the  canal  into  the  general  cavity  of  the  body,  mixing  there  with  that 
already  existing,  and  is  the  representative  of  the  blood  of  higher  animals. 
But,  in  addition  to  this,  a  constant  renovation  of  the  chyhferous  liquid  of  the 
body,  by  Avater  taken  in  from  without,  appears  to  be  necessaiy. 

Ehrenberg  witnessed  a  periodical  transparency  in  the  body,  with,  an  alter- 
nating distension  and  collapse  occurring  regularly  in  almost  all  Rotatoria. 
During  distension,  the  outline  of  all  the  viscera  seemed  clearer,  whilst,  upon 
the  collapse,  the  organs  approximated  their  limits,  became  less  defined  and 
somewhat  confused,  and  the  integiunent  crumpled.  These  movements  he  attri- 
buted to  the  alternate  entrance  and  exit  of  water  from  without,  through  the 
medium  of  the  supposed  siphon  tube  on  the  head,  or  of  oj)enings  upon  other 
parts  of  the  body.  It  has,  however,  been  shown  that  the  siphon  and  apparent 
openings  have  no  external  commimication ;  we  must  consequently  believe,  with 
Ley  dig,  that  the  imbibition  and  exudation  must  be,  in  great  measure,  the 
result  of  endosmotic  action, — not  forgetting,  however,  the  influence  w^hich  is 
necessarily  exerted  on  the  alternate  movements  in  question  by  the  action  of 
the  respiratory  apparatus  to  be  presently  described. 

Leydig  remarks  that  "  the  mingling  of  the  sanguineous  fluid  Tvith  water 
from  without  seems,  at  first  sight,  extraordinary ;  it  is,  however,  a  fact  in 
physiology,  founded  on  direct  obsei-vatiou,  Yan  Beneden  having  detected  it 
in  marine  Mollusca,  myself  in  Paludina  vivipara,  and,  more  recently,  Gegen- 
baui'  in  Heteropoda  and  Pteropoda.'^  The  nutritive  or  sanguineous  fluid  of 
the  Rotatoria  is,  as  a  rule,  clear  and  colourless,  but  in  some  species  it  has  a 
red  or  yellowish  hue,  e.  g.  in  Notommata  centrura,  Synch(eta,  and  Polyarthra ; 
it  is,  moreover,  usually  destitute  of  distinct  floating  particles  or  elements  : 
exceptions  occiu-  in  Eospliora  Najas,  Eucidanis,  and  a  few  others,  in  which 
small  clear  corpuscles  move  about  in  it  just  as  in  the  blood  of  Annelida.  ''  Such 
genuine  elements,"  continues  Leydig,  "  of  the  circulating  fluid  must,  however, 
not  be  confoimded  with  the  Tuinute  particles  which  at  times  detach  themselves 
from  the  tissues  mthin  the  body  and  float  about  in  the  liquid.  Such  false 
corpuscles  are  not  uncommon  in  animals  which  have  been  partially  crushed 
or  left  diy  by  evaporation ;  those  noticed  by  Ehrenberg  in  Hydatina  senta 
were,  in  all  probability,  of  this  accidental  kind." 

Dr.  Dobie  has  recorded  an  observation  of  seemingly  genuine  moving  cor- 
puscles, which  deserves  a  place  here.  He  found,  *'  immediately  below  the 
integument  of  Floscidaria  cornuta,  groups  and  lines  of  very  small  granules 
continually  in  a  state  of  rapid  molecular  motion,  in  appearance  exactly  resem- 
bling the  molecules  in  the  cusps  of  Olosterium.  Besides  the  molecular,  they 
are  subject  to  another  motion ;  for  occasionally  they  move  from  one  part  of 


428  GENEEAL  HISTORY  OF  THE  INFUSORIA. 

the  surface  to  another,  in  currents  not  very  distinct  or  persistent,  and  in  no 
definite  direction.  He  has  seen  them  running  in  lines  down  the  tail,  and 
collecting  in  groups.  This  flowing  movement  occurs  chiefly  during  the  con- 
tractions and  relaxations  of  the  entire  animal.  He  thinks  it  probable  that 
these  granules  are  connected  with  the  nutrition  of  the  animal,  and  analogous 
to  the  free  floating  corpuscles  of  the  Tardigrada,  described  by  M.  Doyere." 

In  his  recent  paper  (Mliller's  Archiv,  1857,  p.  404),  Leydig  notes  that 
when  individuals  of  Hydatina  senta  have  been  plentifully  fed  with  Euglejia 
viridis,  the  fluid  (blood)  which  fills  their  abdominal  cavity,  contains  numerous 
clear  globules,  or  blood-corpuscles,  of  a  roundish  form  and  unequal  size.  We 
would  rather  compare  these  corpuscles  to  those  seen  in  chyle  during  the 
process  of  digestion,  as  more  strictly  homologous  with  them  than  with  blood- 
disks.  Although  no  true  vascular  system  is  discoverable  in  the  Rotatoria, 
there  is,  nevertheless,  a  tubular  apparatus  readily  seen  in  most  animals  of  the 
class  (XXXYI.  6  a  a,  9  m ;  XXXVII.  29  d,  32  ef;  XXXVIII.  5  d  d,  25  ef, 
2Q  eil,  27  g).  It  has  the  form  of  an  apparent  band,  extends  upwards  from 
the  cloaca,  or  near  to  it,  on  each  side  of  the  body ;  and  within  this  a  cord  or 
vessel  is  visible,  more  or  less  coiled  or  convoluted  in  its  com^se,  from  which 
small  vibrating  organs,  often  pear-shaped,  and  likened  by  Ehrenberg  to 
written  notes  of  music,  project  towards  the  cavity  of  the  body.  These  vessels 
may  possibly  communicate  by  one  or  more  transverse  vessels  running  across 
the  neck  of  the  animal ;  whilst  below,  they  end  either  in  a  vesicle  endowed 
with  an  active  power  of  contractility  or  immediately  in  the  cloaca  itself. 

Xow  it  happens  that  the  mechanism  of  this  organization,  as  well  as  its 
fimctions  and  relations  to  the  other  parts  of  the  body,  have  been  so  variously 
described  by  different  waiters,  that  it  is  difficult  to  draw  up  any  satisfactory 
general  account  of  it ;  we  shall  therefore  be  compelled  chiefly  to  conflne 
ourselves  to  the  reproduction  of  the  several  statements  as  presented  by  their 
authors  respecting  the  side  bands  and  the  contractile  vesicle.  Ehrenberg 
adopted  the  curious  notion  that  they  were  parts  of  the  sexual  organization. 
The  side  bands  with  their  coiled  canal  he  represented  to  be  the  testes,  and 
the  contractile  vesicle  a  sperm -sac  (seminal  vesicle).  The  inconsistency  of 
this  notion  with  all  oiu'  knowledge  of  animal  structure  and  fimctions,  has 
struck  every  observer.  To  adduce  but  one  coimterargument : — the  constant 
discharge  of  spermatic  fluid  in  a  profuse  quantity,  and  in  no  relation  with  the 
number  of  eggs  contained  within  the  ovaiy,  is  an  idea  which  is  per  se  at  vari- 
ance with  all  analogy,  and  directly  opposed  by  the  fact  that  the  apparatus  is 
in  full  activity  even  when  the  embryo  is  still  unhatched  mthin  the  body  of 
its  parent, — and  entirely  negatived,  at  least  in  several  instances,  by  the  disco- 
very of  distinct  male  beings. 

Again,  Ehrenberg  called  the  tremulous  tags  (XXXVIII.  26  e)  gills  or  gill- 
like organs,  and  therein  recognizes  them  as  parts  of  a  respiratory  system.  He 
thus  refers  to  them : — "  Oval,  tremulous  bodies  are  in  some  species  observed 
attached  to  a  free  filament-like  tube  generally  placed  longitudinally  mthin 
the  body ;  in  some  instances  they  are  attached  to  the  two  sexual  glands  {i.  e. 
the  side  bands),  as  in  Hydatina.  Their  function  is  respiratory,  and  they  are 
analogous  to  gills ;  the  tremulous  motion  observable  is  that  of  the  laminae 
composing  them.  The  reception  of  water  within  the  body  for  these  gills  to 
act  upon,  is  provided  for  by  one  or  more  openings  at  the  anterior  part  of  the 
body,  or  in  some  species  by  spur-like  processes  or  tubes  (siphons)." 

The  erroneous  belief  that  the  siphon-like  antennae  (XXXVII.  17  d; 
XXXVIII.  27  e)  and  the  cuticular  fossae  were  channels  for  the  admission  of 
water  into  the  body  was  countenanced  by  Siebold,  who  explained  the  respi- 
ratory act  to  consist  in  the  entrance  of  water,  by  the  supposed  apertures,  from 


OF  THE  ROTATORIA.  429 

without  into  the  general  cavity  of  the  body,  its  percolation  through  ^*  short 
lateral  vessels  "  (the  oscillatory^  tags)  into  the  winding  canal  of  the  lateral 
band  of  each  side,  and  its  passage  thence  into  the  contractile  vesicle,  by  which 
it  is  pumped  out  through  the  cloaca.  This  process  Siebold  designated  a  water- 
circulating  system. 

Mr.  Dakymple,  in  his  excellent  description  of  a  supposed  new  Notommata 
(the  Asplanclma  Brightwellii  of  Gosse),  differs  from  Siebold  in  the  account 
of  the  respiratory  apparatus  in  several  particulars.  He  says — ''  This  pecu- 
liar organ  consists  in  a  double  series  of  transparent  filaments  (for  there  is  no 
proof  of  their  being  tubes  or  vessels),  arranged,  from  above  downwards,  in 
curved  or  semicircular  form,  symmetrical  when  viewed  in  front  (XXXVI. 
6  a  a).  These  filaments,  above  and  below,  are  interlaced,  loop -like,  while 
another  fine  filament  passes  in  a  straight  line  like  the  chord  of  an  arc,  uniting 
the  two  looped  extremities.  To  this  delicate  filament  are  attached  little  tags 
or  appendices,  whose  free  extremities  are  directed  towards  the  interior  of  the 
animal,  and  are  effected  by  a  tremulous,  apparently  spiral  motion,  like  the 
threads  of  a  screw.  This  is  undoubtedly  due  to  cilia  arranged  round  these 
minute  appendices.  The  tags  are  from  eight  to  twelve,  or  even  twenty,  in 
number,  varying  in  different  specimens  (XXXVI.  6). 

"  I  beheve  the  organ  in  question  to  be  a  peculiar  circulatory  system.  The 
body  of  the  animal  is  filled  with  fluid,  most  probably  analogous  to  blood, 
while  the  ciliated  tags,  in  perpetual  motion,  must  produce  currents  in  this 
fluid,  and  probably  iu  a  uniform  and  determinate  dii^ection.  In  this  way  the 
nutrient  plasma  will  be  brought  regularly  ia  contact  with  all  parts  of  the 
body,  and  the  process  of  nutrition  go  on  as  in  insects,  mthout  the  interven- 
tion of  tubular  vessels, — the  dorsal  heart  in  them  serving  only  to  give  direc- 
tion and  circulation  to  the  blood.  I  am  the  more  impressed  with  this  belief, 
since  these  filamentous  organs  are  in  close  approximation  with  the  large  con- 
tractile sac,  which  probably  performs  a  respiratory  function." 

Moreover  Mr.  Daliymple  does  not  believe  in  any  communication  between 
the  sac  and  the  apparatus  furnished  with  the  ciliated  tags,  as  Siebold  supposes  ; 
on  the  contrary,  he  represents  the  sac  to  commimicate  directly  with  the  ex- 
terior. He  writes — "  This  sac,  spherical  when  distended,  is  placed  just 
above  the  ovisac,  and  communicates  with  the  vaginal  canal.  It  is  ex- 
ceedingly delicate,  and  may  be  seen  to  contract,  by  the  action  of  muscular 
fibres,  with  great  rapidity,  in  which  act  it  is  thrown  into  numerous  regular 
folds  or  pouches,  and  in  that  condition  appears  not  very  dissimilar  to  the 
large  cellular  limgs  of  Batrachia ....  The  explanation  which  I  venture  to  give 
is,  that  this  sac  draws  in  water  and  expels  it  again  by  the  vaginal  orifice ; 
and  it  is  by  bringing  the  blood,  by  means  of  the  ciliary  movements  of  the 
tags,  into  immediate  contact  (the  delicate  membranous  wall  of  the  sac  in- 
tervening) with  the  air  of  the  water,  that  aeration  or  respii-ation  is  per- 
formed.    An  analogous  contractile  sac  may  be  seen  in  Rotifer  vulgaris.'' 

Lastly,  the  author  adds  that  he  is  convinced,  from  repeated  observation, 
that  the  contractile  sac  has  no  relation  with  the  generative  function,  and 
that  *'  the  supposed  vascular  ramifications  upon  it  are  neither  more  nor  less 
than  the  muscular  fibrillae  by  which  the  contractions  are  effected." 

Perty  coincides  with  the  explanation  offered  by  Daliymple,  and  reproduces 
it  in  his  work.  Mr.  Gosse  presents,  in  his  notice  of  AsjyJanchna  2>^odonta, 
the  following  description  of  the  mechanism  in  question  : — "  On  the  upper 
side  of  the  oviduct  sits  a  contractile  bladder,  which,  when  full,  is  perfectly 
globular  and  small,  being  scarcely,  if  at  all,  larger  than  the  two  pancreatic 
glands  put  together.  Eound  this,  attached  at  or  near  its  base,  passes  on  each 
side  a  tortuous  thread,  apparently  glandular,  which  goes  up  along  each  side 


430  GENERAL  niSTORY  OF  THE  INFUSORIA. 

of  the  ventral  region,  and  is  attached  to  the  head-mass  behind  the  jaw- 
cushion.  The  middle  part  of  each  thread  is  wrinkled  into  a  large  plexus  of 
four  or  five  pairs  of  doublings,  laid  with  some  regularity  ;  on  this  plexus  are 
placed  four  tremulous  tags,  directed  inwards,  making  eight  in  all.  jN'one  are 
visible  on  any  other  part  of  the  threads.  The  presence  of  these  organs,  as 
well  as  of  the  contractile  bladder,  in  the  female,  shows  that  these  are  not  con- 
nected with  impregnation. 

From  the  above  extract  it  appears  that  Mr.  Gosse  believes  that  the 
"  tortuous  threads  "  of  the  apparatus  have  a  glandular  ofiice  ;  and  though  he 
so  far  countenances  the  hypothesis  of  Ehrenberg,  nevertheless  pronounces 
against  their  sexual  nature. 

Dujardin  expresses  an  opinion  that  the  contractile  vesicle  is  a  respiratory 
organ,  and  that  the  water  freely  penetrates  into  the  interior  of  the  body  to 
bathe  the  vibratile  organs,  as  the  variability  of  volume  of  the  animals  proves. 

Leydig  has  very  elaborately  described  the  structures  in  question,  and  their 
several  modifications.  We  feel  justified  in  submitting  an  analysis  of  his 
researches,  even  at  the  risk  of  some  repetition : — 

"  The  canal  of  the  respiratory  apparatus  extends  along  each  side  of  the  body. 
Generally  there  is  a  single  canal  on  each  side,  much  contorted  in  its  course, 
and  forming  actual  coils  or  plexuses,  e.  g.  in  Steplianoceros,  Bracliioncea, 
Lacinularia,  Euchlanidota,  and  many  Notommatce.  Two  canals,  which 
coalesce  at  either  end,  are  seen  in  Notommata  Myrmeleo,  N.  SiehoJdii,  N. 
Syrinx,  N.  clavidata,  and  N.  AncjUca.  The  canals  have  a  thick  cellular  wall, 
and  their  cavity  is  clear  and  well  defined.  They  are  not  solid  cords,  as  Perty 
and  others  affirm.  The  cellular  walls  may  be  much  thickened,  and  contain, 
besides  the  usual  fine  granular  contents,  many  fat-particles,  as  seen  in  Ste- 
phanoceros,  Notommata  centrura,  and  in  Lacinidaria.  In  the  first-named, 
indeed,  the  deposit  of  fat  is  so  great  that  the  coils  of  the  respii'atory  canal 
near  the  head  rather  resemble  a  collection  of  fat- vesicles  (XXXVII.  1  t).  I 
have  not  been  able  to  discover  any  anastomoses  between  the  canals  of  opposite 
sides,  as  Huxley  represents  in  Lacinidaria.^^ 

In  many  Eotatoria,  particularly  in  small  species,  such  details  of  structure 
escape  our  powers  of  observation,  and  the  canals  described  are  invisible,  as,  for 
example,  in  Floscidaria,  Polyartlira,  ^n^Ascomorpha;  a  more  close  and  search- 
ing inquiiy  may,  however,  reveal  them,  particularly  where  the  contractile  sac 
shows  itself.    Indeed,  Perty  has  detected  the  tubes  in  Ascomorpha  Helvetica. 

"  The  vibratile  or  cihated  tags  are  processes  of  the  respiratory  canal  (XL. 
5).  They  are  constructed  after  two  tj^^es,  which  do  not  concur  in  the  same 
animal,  but  are  found  as  peculiarities  of  different  genera.  In  one  ij^Q  the 
process  is  of  equal  width  and  cylindrical  throughout,  as  in  Notommata 
Myrmeleo  (XXXYIL  29  e,  32  h) ;  in  the  other,  the  extremities  are  dilated 
and  a  trumpet- shaped  figure  assumed,  as  in  Notommata  centrura  (XXXYIII. 
26  e),  Euchlanis  triquetra,  and  in  Eospliora  Najas. 

^'  In  Lacinularia  I  have  been  unable  to  satisfy  myself  if  these  processes  of 
the  respiratory  canal  discharge  themselves  freely  into  the  abdominal  cavity. 
Huxley  states  that  they  have  bhnd  extremities ;  but  I  regard  it  as  still  an 
open  question,  for  in  other  species,  for  example  in  Notommata  Sieboldii  and 
N.  centrura,  it  can  be  most  satisfactorily  made  out  that  they  open  freely  into 
the  cavity  of  the  body. 

"  Vibratile  haii'S  (cilia)  project  from  their  free  end  and  in  the  trumpet- 
shaped  processes  ;  the  direction  of  the  ciliary  motion  is  e\ddently  inward. 

'*  The  number  of  the  vibratile  organs  varies  much  in  different  species : 
usually  there  are  but  from  4  to  8  or  10,  distributed  at  unequal  distances  along 
the  respiratory  tube ;  but  in  some  animals,  e.  r/.  in  Noto7nmata  Copeus,  N. 


OF  THE  ROTATORIA.  431 

Syrinx,  N.  Sieholdii,  N.  Anglica,  N.  clavulata,  and  in  JSf.  Myrmeleo,  the 
number  is  greatly  augmented,  and  from  30  to  50  tags  may  be  counted.  When 
thus  multiphed,  they  are  for  the  most  j^art  appended  to  a  clear  canal  of  Httle 
width  and  thickness,  rather  than  to  one  with  thick  cellular  walls.  (The  tags 
are  mostly  more  numerous  on  one  side  than  on  the  other.) 

"  The  posterior  extremities  of  the  respiratory  canals  either  open  at  once 
into  the  cloaca,  as  in  Tuhkolaria,  or  more  commonly  expand  to  form  the 
contractile  scu?,  the  respiratory  vesicle  (XXXVIII.  26  i). 

'^  At  the  first  appearance  of  the  respii^atory  vesicle,  it  is  of  insignificant  size, 
and  clearly  a  dilated  state  of  the  united  ends  of  the  two  respiratory  canals. 
It  is  then  little  or  not  at  all  contractile.  This  condition  is  illustrated  in 
Lacinnlaria  and  Steplianoceros.  "  It  generally,  however,  exists  as  a  consider- 
able and  actively  contractile  sac  opening  into  the  cloaca.  Its  walls  are  very 
thin,  and  covered  with  a  fine  muscular  network,  discoverable  in  most  species, 
and  imagined  by  Ehrenberg  to  be  vascular.  The  openings  of  the  respiratory 
canals  into  this  sac  are  readily  perceived  by  a  proper  adjustment  of  the  focus 
of  the  microscope." 

From  this  organization,  Ley  dig  concludes  that  a  portion  of  the  water  sur- 
roimding  the  animal  enters  by  endosmosis,  or  possibly  by  minute  orifices 
hithei-to  unperceived,  within  the  cavity  of  the  body,  and  there  mixes  with 
the  nutritive  juices,  the  analogue  of  the  blood  of  higher  beings.  The  simple 
act  of  respiration  is  consequently  limited  to  the  imbibition  and  the  intermix- 
ture of  fresh  water  with  the  blood.  Further,  it  would  appear  that  the  waste 
material  is  discharged  through  the  vibratile  processes,  which  by  their  ciliated 
appendages  direct  the  fluid  into  the  respiratory  canals,  from  which  it  escapes 
either  fii'st  into  the  contractile  sac,  and  thence  into  the  cloaca,  or  at  once  into 
the  latter. 

Here  the  question  of  a  glandular,  a  renal  function  performed  by  the  re- 
spiratory tubes  meets  us  ;  but  it  will  be  more  convenient  to  defer  its  consi- 
deration until  we  have  set  forth  the  researches  of  iSlr.  Huxley,  who  differs  in 
not  a  few  details  from  Leydig : — we  must  premise  that  they  api)ly  specially 
to  the  Lacinidaria  socicdis,  to  which,  among  other  peculiarities,  he  assigns  the 
absence  of  a  contractile  sac,  although  Leydig  affirms  a  veiy  small  one  to 
exist. 

Prof.  Huxley  acquaints  us  that  the  opinion  of  Oscar  Schmidt  is,  "  that  the 
ends  of  the  water- vessels  are  closed,  and  that  the  vibrating  body  is  within 
them."  And  he  goes  on  to  say — ''  There  is  no  contractile  sac  opening  into 
the  cloaca  as  in  other  genera ;  but  two  veiy  delicate  vessels  about  ^^th  of 
an  inch  in  diameter,  clear  and  colourless,  arise  by  a  common  origin  upon  the 
dorsal  side  of  the  intestine.  AVhether  they  open  into  this,  or  have  a  distinct 
external  duct,  I  cannot  say. 

"  The  vessels  separate ;  and  one  runs  up  on  each  side  of  the  body  towards 
its  oral  side.  Arrived  at  the  level  of  the  phaiyngeal  bulb,  each  vessel  divides 
into  three  branches :  one  passes  over  the  pharynx  and  in  front  of  the  pha- 
rjTigeal  biilb,  and  unites  with  its  feUow  of  the  opposite  side,  while  the  other 
two  pass,  one  inwards  and  the  other  outwards,  in  the  space  between  the  two 
layers  of  the  trochal  disk,  and  there  terminate  as  caeca.  Besides  these,  there 
sometimes  seemed  to  be  another  branch  just  below  the  pancreatic  sacs. 

"A  vibratile  body  was  contained  in  each  of  the  csecal  branches ;  and  there 
was  one  on  each  side  in  the  transverse  connecting  branch.  Two  or  more 
were  contained  in  each  lateral  main  trunk,  one  opposite  the  pancreatic  sacs, 
and  one  lower  down,  making  in  aU  five  on  each  side.  Each  of  these  bodies 
was  a  long  cilium  (y^L-^th  of  an  inch)  attached  by  one  extremity  to  the  side 
of  the  vessel,  and  by  the  other  vibrating  with  a  quick  undulatory  motion  in 


432  GENEEAL  HISTORY  OF  THE  rNFUSORIA. 

its  cavity.     As  Siebold  remarks,  it  gives  rise  to  an  appearance  singularly  like 
that  of  a  flickering  flame. 

'^  I  particularly  endeavoured  to  find  any  appearance  of  an  opening  near  the 
\ibratne  cilium,  but  never  succeeded,  and  several  times  I  thought  I  could 
distinctly  observe  that  no  such  aperture  existed.  Animals  that  have  been 
kept  for  some  days  in  a  limited  amount  of  water  are  especially  fit  for  these 
researches.  They  seem  to  become  in  a  manner  dropsical ;  and  the  water- 
vessels  partake  in  the  general  dilatation. 

"  The  band  which  accompanies  the  vessel  appeared  to  me  to  consist  merely 
of  contractile  substance  (connecting-tissue),  and  to  serve  as  a  mechanical 
support  to  the  vessel.  It  terminates  above  in  a  mass  of  similar  substance 
containing  vacuola  attached  to  the  upper  plate  of  the  trochal  disk." 

This  account  difi'ers  from  that  of  Leydig  chiefly  in  the  denial  of  the  patent 
condition  of  the  free  ends  of  the  vibratile  tags,  and  consequently  of  the  en- 
trance of  the  fluid  from  the  cavity  of  the  body  through  them  into  the  lateral 
vessel.  It  also  casts  doubt  upon  coils  of  the  water- vessel  in  the  neck,  and 
upon  the  presence  of  a  small  non- contractile  sac  at  the  inferior  termination 
of  the  lateral  vessels,  whilst,  on  the  other  hand,  it  represents  anastomosing 
branches  between  the  vessels  of  opposite  sides  in  the  neck.  Mr.  Huxley's 
description  therefore  appears  rather  to  favoui'  Mr.  Dahymple's  hypothesis 
as  to  the  contractile  vesicle,  whilst,  with  respect  to  the  lateral  canals,  it  is 
suggestive  of  a  glandular  excretory  function. 

Dr.  Carpenter  adopts  Prof.  Huxley's  description  of  the  tags,  and  of  the 
inosculating  vessels  in  the  neck. 

Cohn,  in  his  account  of  Hydatina  scyita  (Zeitschr.  f.  Zool.  1855,  p.  444), 
describes  two  tubes  as  springing  from  the  thick-waUed,  muscular  contractile 
sac,  lying  on  the  abdominal  surface  of  the  animal,  immediately  subjacent  to 
the  skin,  and  communicating  with  the  cloaca.  These  tubes  are  "  respiratory 
canals;  "  they  have  a  finelj-  granular  wall,  and  advance  with  more  or  fewer 
curvatures  and  coils  towards  the  head,  where  they  appear  to  end  in  straight, 
blind,  pointed  ends  or  in  loops,  which  attach  themselves  to  the  skin  of  the 
rotary  organ.  The  ''tags,"  four  on  either  side,  afiixed  to  the  canal  are 
triangular  in  one  aspect,  and  shortly  cylindi'ical  in  another,  and  supported 
on  short  pedicles,  through  which  their  cavity  becomes  continuous  with  the 
interior  of  the  canals.  The  different  figure  of  the  tags  from  different  points 
of  view  has  given  rise  to  the  error  of  their  being  of  two  sorts — cylindrical 
and  triangular.  In  Bracliionus  militaris  the  contractile  vesicle  is  remarkable 
on  account  of  its  very  large  dimensions.  It  occupies  as  much  as  two-thirds 
of  the  abdominal  cavity,  and  is  composed  of  two  chambers,  of  which  the 
posterior  is  the  larger.  The  diastole  and  systole  of  the  two  chambers  are 
alternate  ;  the  posterior  opens  into  the  cloaca,  through  a  small  duct.  That 
there  is  a  direct  communication  between  the  contractile  sac  and  the  cloaca, 
Cohn  decisively  proved  by  mingling  colouiing  matter  in  the  water,  and  wit- 
nessing a  current  inwards  dui'ing  each  dilatation,  and  one  outwards  on  each 
act  of  contraction,  alternately — an  experiment  sufficiently  conclusive  of  the 
respiratory  natui^e  of  the  sac. 

The  mechanism  under  consideration  appears,  as  Leydig  also  remarks,  to  be 
occasionally  absent — or  perhaps  only  imperceptible.  Dr.  Dotie  states  that 
in  FJasculaina  "  no  trace  of  a  vascular  system  can  be  obsei-ved.  The  tremulous 
giU-hke  organs  found  in  some  Rotifers  are  here  absent."  After  his  complete 
examination  of  Melicerta  ting  ens,  Prof.  Williamson  says — "  I  have  found  no 
special  organs  of  circulation  or  respiration ....  I  detect  no  vessels  or  pulsating 
organs."  Nevertheless  a  structui-e  at  least  resembling  the  \dbratile  tags  was 
noticed  in  this  animal  by  Mr.  Gosse,  who  states  that  between  the  gizzard 


or  THE  ROTATORI  V.  433 

"  and  the  base  of  the  stomach  there  was  one  httle  tremulous  tag,  of  the  same 
structure  as  in  Notommata  aurita.  From  the  same  spot  also  project,  into  a 
space  of  peculiar  clearness,  two  trnmpet-shaped  bodies  of  the  greatest  delicacy, 
and  without  motion."  Prof.  WiUiamson  reminds  us,  in  a  note,  that  he  has 
described  two  tubes  springing  from  a  pyriform  organ,  apparently  hollow,  and 
located  immediately  below  the  stomach.  Though  he  saw  no  pulsation  in  this 
organ,  it  appeared  to  be  the  homologue  of  the  contractile  yesicle  in  other  species. 
He  belieyes  the  two  filamentous  organs  to  be  tubular,  and  suggests  the  possi- 
bihty  of  their  supplying  a  spermatic  secretion,  though  he  is  not  able  to  affirm  it 
as  a  fact.  He  moreoyer  obseryed  the  \'ibratile  spermatozoon-like  corpuscles 
"  in  yarious  parts  of  the  body,  where  they  are  apparently  enclosed  within 
hollow  canals.  I  have  never  seen  them  occupying  the  two  main  trunks  of 
the  ivater-vascular  system,  as  caeca,  nor  can  I  succeed  in  tracing  any  con- 
nexion between  them  ;  "  but  it  is  probable  that  they  were  really  located  in 
some  of  the  branches  of  that  system,  as  observed  by  Mr.  Huxley  in  Lacinu- 
Imia. 

The  glandular  renal  function  of  the  lateral  tubes  and  appendages  has  the 
support  of  analogy  among  other  lowly- organized  forms  allied  to  the  Rotatoria  ; 
but  such  an  hj-pothesis  falls  to  the  ground,  if,  as  Leydig  thinks,  the  urinary 
concretions  noticed  and  so  named  by  him  in  embryo  and  young  animals  are 
deposited  within  the  cavity  of  the  intestine,  and  not  in  the  contractile  sac. 
However,  naturalists  generally  will  certainly  not  accept  the  doubtful  disco- 
very of  the  position  and  the  interpretation  of  the  nature  of  the  particles 
oifered  by  Leydig  as  conclusive  evidence  of  the  natm^e  of  those  structures, 
but  will,  in  the  absence  of  direct  and  exact  observation,  be  rather  guided  by- 
analogy.  ^Ye  will  therefore  append  some  extracts,  showing  the  comparative 
physiology  of  the  supposed  respiratory  mechanism. 

Leydig  writes — "  There  is  the  greatest  similarity  between  it  and  the 
organs  in  Lumbricince  and  HirucUnce,  which  are  conceived  to  have  a  respira- 
tory office.  In  these  are  similar  contorted  and  coiled  tubes,  with  a  clear 
canal  opening  either  without  an  intermediate  contractile  sac,  as  in  Clepsine, 
or  with  one,  as  in  Nephelis.  Moreover,  the  canal  opens  by  a  wide  ciliated 
aperture  into  the  cavity  of  the  body ;  and  in  this  termination  of  the  tubes  I 
recognize  the  homologue  of  the  vibratile  tags  of  the  Rotatoria.  Moreover, 
the  dii-ection  of  the  ciliary  motion  in  the  Annelida  is  inwards  to  the  main 
canal.  In  the  Lumbricince,  Gegenbauer  has  attributed  a  renal  function  to 
the  otherwise-called  respiratory  canal." 

Dr.  Carpenter  describes  a  '' water-vascular  system  "  among  all  the  vermi- 
form members  of  the  Articulata,  and  as  represented  in  its  simplest  type  in  the 
Rotifers.  "  Similar  lateral  vessels,  often  ramifying  more  minutely  (especially 
in  the  head  and  anterior  part  of  the  body),  are  found  in  many  of  that  group  of 
vermifoi-m  animals  clothed  over  the  whole  surface  of  theii'  bodies  with  cilia,  to 
which  the  designation  TurbeUaria  has  been  given."  This  writer  surmises 
that  the  water-vascular  system  may  contain  some  other  fluid  than  pure  water, 
and,  as  Van  Beneden  has  suggested,  may  serve  as  a  urinary  apparatus. 

Prof.  Huxley  presented  the  followiug  philosophical  summar}^  of  the  com- 
parative relations  of  the  respiratory  mechanism  of  the  Rotifer ;  before  the 
British  Association : — ''  In  certain  Distomata,  such  as  Aspidogaster,  there  is 
a  system  of  vessels  of  essentially  similar  character  with  that  in  Rotifer  ;  but 
the  principal  canals,  those  lateral  trunks  which  come  dii^ectly  from  the  con- 
tractile vesicle,  present  regular  rh^^hmical  contractions.  The  smaller  branches 
are  aU  richly  ciliated.  In  other  Distomata  the  lateral  trunks  appear  to  be 
converted  into  excretory  organs,  as  they  are  full  of  minute  granules  :  they 
remain  eminently  contractile ;  but  their  connexion  with  the  system  of  smaller 

2f 


434  GEIS^ERAL  HISTORY  OF  THE  INFUSORIA. 

ramified  vessels  ceases  to  be  easy  of  demonstration.  They  still  form  one 
system  ;  but  the  ciha  are  no  longer  to  be  fonnd  in  the  smaller  ramified  vessels. 
In  certain  Nematoidea  the  vascular  system  is  reduced  to  a  couple  of  lateral 
contractile  vessels  altogether  devoid  of  cilia,  but  communicating  with  the 
exterior  by  a  small  apertm-e.  Now  in  all  these  cases  there  is  no  doubt  the 
vascular  system  is,  physiologically,  a  respiratory  and  j^erhaps  a  urinary  system, 
while  the  common  cavity  of  the  body  represents  the  blood-vascular  system  of 
the  Mollusca  and  Articulata.  If  this  system,  then,  be  not  at  all  homologoiLs 
with  the  blood-vascular  system  of  the  higher  Annulosa,  it  is  so  with  the 
tracheae  of  Insecta." 

We  may  repeat  here  that  the  delicate  and  ciliated  rotary  organ  must  in 
some  measiu-e  subserve  the  purpose  of  respiration,  after  the  manner  of  the 
gills  of  a  reptile  or  of  a  fish,  by  providing  for  the  aeration  of  the  hquids 
contained  within  it  through  the  agency  of  the  constantly  renewed  contact  of 
fresh  water  flowing  over  its  actively- vibratile  surface. 

OF    THE    NEEVOUS    SYSTEM    AND    THE  ORGANS    OF   SENSE  ;     PSYCHICAL 
ENDOWMENTS. 

a.  Of  the  Nervous  System.  —  The  existence  of  a  rudimentary  nervous 
system  is  now  universally  admitted ;  but  at  the  period  when  Dujardin  wrote, 
that  talented  observer  felt  that  the  state  of  knowledge  respecting  the  Rota- 
toria was  not  sufficiently  precise  to  estabhsh  the  existence  of  nerves  and  of 
nervous  ganghons.  His  scepticism  was,  no  doubt,  increased  by  observing  the 
imphilosophical  facility  with  which  Ehrenberg  described  and  represented 
nerve-cords  and  ganglions  according  to  preconceived  notions  and  loose  ana- 
logies. Illustrations  of  Elu^enberg's  supposed  nervous  apparatus,  and  of  its 
modifications  of  form  in  different  animals,  are  to  be  found  in  his  descriptions 
of  every  family  and  genus.  Thus  in  giving  the  characters  of  Lacinidaria,  he 
says  that  ''  near  the  oesophagus  is  situated  a  nervous  mass,  the  analogue  of 
a  brain  chvided  into  four  or  six  lobes ;  also,  as  in  Megahtroclia  (XXXII.  374), 
two  ring-like  and  radiating  masses  with  a  row  of  ganglions  Ijing  beneath  the 
muscles  of  the  cihary  wreath."  In  Mellcerta,  he  speaks  of  a  ciu'ved  gland- 
like band  of  nerve-matter ;  in  Etiterojplea,  which  has  no  eyes,  of  a  brain-like 
knot,  sending  off  a  thick  tortuous  nerve-cord  along  the  dorsal  siu-face  to  the 
second  transverse  vessel,  where  the  rcspii'atory  opening  probably  exists ;  of  a 
ganglion  placed  beneath  the  e3^e  in  twenty-six  species  of  Notommata,  which 
in  N.  Copeus  and  N.  centnira  is  three-lobed  and  seated  above  the  maxillary 
bulb,  whilst  in  the  remainder  it  consists  of  one  or  more  nervous  gangha 
seated  amidst  the  muscles  of  the  cihary  apparatus ;  and  in  Otoglena,  of  an 
oval  cerebral  ganglion  with  two  dark  appendages,  a  red  eye,  a  long  neiTC- 
loop  in  the  neck,  with  a  prolongation  backward,  a  forked  ventral  nerve,  and 
two  ear-shaped  frontal  protuberances  bearing  two  visual  points. 

It  would  be  useless  to  multiply  these  references ;  the  general  deduction 
from  the  many  descriptions  of  Ehrenberg  is,  that  there  exists  a  cerebral  or 
brain  ganghon,  which  supports  the  eyes,  and  by  its  extension  enciiTles  the 
CBSophagus  like  a  loop,  sending  off  nerve-cords  in  every  dii'ection,  and  often 
complicated  by  the  presence  of  other  nerve -ganglions  about  the  head,  neck, 
and  body.  Moreover,  the  apparent  reticulations  frequently  visible  below  the 
ciliary  wreath,  which  he  sometimes  viewed  as  a  vascular  network,  he  at 
others  spoke  of  as  a  nervous  plexus. 

The  present  prevaiHng  opinion  is  similar  to  the  above,  viz.  that  there  exists 
a  brain  or  central  nerve-ganglion  above  the  oesophagus,  with  outgoing  nerve- 
fibres,  and  sometimes  accompanied  by  supplementary  ganglia  in  other  regions. 
Xevertheless  the   special  descriptions  of  Ehrenberg  arc  not  accepted ;  the 


OF  THE  ROTATCRIA.  435 

portions  of  tissue  fixed  on  by  him  as  nervous  masses,  receive  in  general  an 
entii^ely  different  intei-pretation.  Thus  in  the  case  of  Lachmlaria  the  sup- 
posed 4-6-lobed  brain,  with  extending  nerve-fibres,  is  set  down  as  mere  col- 
lections of  "  vacuolar  tliickenings,"  with  intercuiTent  fibres  of  connective 
tissue.  The  same  inteipretation  is  extended  to  the  "  nine  pairs  of  ganglia, 
with  fine  interlacing  nerve  fibres,"  in  Notommata  clavulata,  and  to  the  four 
or  five  such  in  Diglena  laciistris ;  yet  in  both  these  species,  the  central  or 
brain  ganglion  represented  by  Ehrenberg  is  allowed  to  retain  this  character 
by  Leydig,  who  sets  aside  all  the  rest  as  mythical. 

The  following  critique  on  Ehrenberg's  views  is  fi'om  Prof.  Williamson  : — 
"  The  small  organs  so  common  amongst  the  Eotifera,  and  which  Ehrenberg 
regards  as  nen'ous  ganglia,  are  abundant  in  the  MeJkerta,  but  they  aff'ord  no 
coimtenance  to  the  hj^^othesis  of  the  great  Prussian  Professor  (XXXVII. 
17  h).  They  appear  to  be  nothing  more  than  small  ceEs,  or  vesicles,  formed 
of  granular  viscid  protoplasm,  very  similar  to  those  into  which  the  yelk  of  the 
eg^  becomes  di\'ided.  Sometimes  the}^  float  freely  in  the  fluid  which  distends 
the  integument  and  bathes  the  viscera  ;  at  others,  thin  ductile  threads  pass 
from  one  vesicle  to  another ....  There  is  no  uniformity  in  their  arrangement 
in  different  individuals.  They  diff'er  as  widely  as  possible  in  their  size, 
number,  and  distribution.  So  far  fi'om  being  nervous  vesicles,  they  appear 
rather  to  be  cells  modified  into  a  rudimentary  foiTQ  of  areolar  (connective) 
tissue.  That  they  are  hollow  vesicles  or  cells,  very  viscous,  readily  cohering, 
and,  o^^g  to  this  coherence,  readily  drawn  out  by  the  movements  of  the 
various  organs  to  which  they  are  attached,  are  facts  capable  of  easy  demon- 
stration." 

A  central  nervous  mass  or  brain,  immediately  subjacent  to  the  eye-specks, 
and  above  the  oesophagus  or  pharynx,  which  sends  off  nerve-fibres  in  different 
directions,  is,  as  already  intimated,  generally  admitted  to  exist.  It  is  men- 
tioned by  Siebold,  Perty,  Gosse,  Dabymple,  Leydig,  Cohn,  and  others.  The 
two  first-named  authors  allude  to  it  as  a  group  of  ganglions ;  but  Leydig 
affirms  that,  although  it  may  be  lobed,  it  is  always  a  single  and  undivided 
organ.  Some,  again,  have  treated  of  it  as  forming  a  loop  or  ring  around  the 
gullet ;  but  such  a  condition  is  denied  by  Leydig,  who  states  that  it  only 
extends  itself  in  the  form  of  diverging  nerves,  which  end  by  enlarged  extre- 
mities, and  never  form  loops,  such  as  Ehrenberg  represented,  around  the 
tubular  process  or  respiratory  siphon. 

This  nervous  centre  or  brain,  supporting  the  eyes,  is  seen  in  the  families 
Hydathum,  Euclilanidota,  and  Brachioncea.  Leydig,  however,  cannot  admit 
the  masses  supposed  to  represent  the  cerebrum  in  the  families  GEcistina,  Mega- 
lotrochcea,  and  Fhscidaria,  nor  the  pairs  of  nerve-hke  ganglions  at  the  base 
of  the  trochal  disk  of  Stephanoceros,  to  have  a  cerebral  character ;  he  supposes 
them  rather  to  be  "  coils  of  the  respiratoiy  canal,  or  heaps  of  granules  or 
nuclei,  such  as  are  met  with  beneath  the  cuticle." 

Prof.  Huxley  discovers  the  nervous  centre  under  a  peculiar  and  unusual 
usual  form  in  Lacinularia  socialis.  To  quote  his  words — "  On  the  oral 
side  of  the  neck  of  the  animal,  or  rather,  upon  the  under  surface  of 
the  trochal  disk,  just  where  it  joins  the  neck,  and  therefore  behind  and 
below  the  mouth,  there  is  a  small  hemispherical  cavity  (about  y^i^j^th  of 
an  inch  in  diameter),  which  seems  to  have  a  thickened  wall,  and  is  richly 
cihated  within.  Below  this  sac,  but  iu  contact  with  it  by  its  upper  edge,  is 
a  bilobed  homogeneous  mass  (about -g-l-jyth  of  an  inch  in  diameter),  resembling 
in  appearance  the  ganglion  of  Bmchionus,  and  running  into  two  prolongations 
below  ;  but  whether  these  were  continued  into  cords,  or  not,  I  could  not  make 
out. 

2f2 


436  OENEKAL  HISTORY  OF  THE  INFUSORIA. 

*'  I  believe  that  this  is,  in  fact,  the  true  nervous  centre,  and  that  the  sac 
in  connexion  with  it  is  analogous  to  the  ciliated  pits  on  the  sides  of  the  head 
of  Nemertidce,  to  the  '  ciliated  sac  '  of  the  Ascidians,  which  is  similarly  con- 
nected with  their  nervous  centre,  and  to  the  ciliated  sac  which  forms  the 
olfactory  organ  of  AmpMoxus. 

*'  Mr.  Gosse  has  described  a  similar  organ  in  MeUcerta  ring  ens  ;  and  I  have 
had  an  opportunity  of  verifying  his  observations,  with  the  exception  of  one 
point.  According  to  this  observer,  the  cilia  are  continuous  from  the  trochal 
disk  into  the  cup  ;  so  far  as  I  have  observed,  however — and  I  paid  particular 
attention  to  the  point, — the  cilia  of  the  cup  are  wholly  distinct  from  those  of 
the  disk.  The  interesting  observations  of  the  same  careful  observer,  upon  the 
architectural  habits  of  MeUcerta,  would  seem  to  throw  a  doubt  upon  the  pro- 
priety of  ascribing  to  the  organ  in  question  any  sensorial  function.  But 
however  remarkable  it  may  seem  that  an  animal  should  build  its  house  with 
its  nose,  we  must  remember  that  a  similar  combination  of  functions  is  ob- 
vious enough  in  the  elephant." 

This  last  analogy  is  assuredly  very  far-fetched,  and  can  serve  nothing  in 
the  argument ;  and  to  us  it  seems  a  much  more  reasonable  supposition  that 
the  homogeneous  bilobed  body  below  the  ciliated  cup  is  a  gland,  than  that  it 
is  a  brain  ;  were  it  a  brain,  surely  some  nerve-iibres  would  be  traceable  from 
it  into  the  interior  of  the  animal.  Of  this  body  Prof.  Williamson  says — "  I 
see  no  sufficient  reason  for  assigning  to  the  small  organ  nervous  functions ;" 
and  he  further  remarks  that  "the  ciliated  sac  or  cup  becomes  so  contracted  when 
the  animal  is  not  busy  in  constructing  its  case,  as  to  be  almost  invisible,"  which 
is  another  circumstance  discountenancing  Prof.  Huxley's  notion  of  its  pur- 
pose. Cohn  has  no  doubt  of  the  cerebral  nature  of  the  large  semiglobular 
mass,  noticed  also  by  Ehi^enberg,  in  the  head  of  Hydatina  senta  ;  and  he 
records  having  frequently  observed  in  its  interior  a  large,  transparent,  circu- 
lar vesicle  or  vacuole.  A  large  number  of  nerves  are  given  off  from  its  an- 
terior portion  ;  but  from  its  posterior,  two  thick  fibres  proceed  backwards  and 
outwards  to  the  apparent  ciliated  opening  on  the  surface  of  the  back,  and 
constitute  a  cervical  loop.  There  is,  however,  no  actual  opening,  but  merely 
a  ciliated  fossa,  which  is  probably  a  sentient  organ.  About  the  large  cerebral 
ganglion  are  other  lobules,  also  probably  nervous,  from  which  fibres  are  given 
off  and  possibly  form  a  plexus  between  the  alimentary  tube  and  ovary,  be- 
sides supplying  the  muscles.  Above  the  ciliated  fossa  named,  is  another  de- 
pression supplied  with  nerves ;  and,  according  to  Ehrenberg,  a  similar  one 
is  present  on  the  oj^posite  side  of  the  bod)*. 

Various  accessory  ganglions  or  nerve-centres  have  been  represented  by 
authors  at  different  parts  of  the  body,  mostly  in  relation  with  some  of  the 
principal  organs,  this  arrangement  being  suggested  by  the  known  nervous 
system  of  other  Invertebrata — for  instance,  the  Mollusca,  which  have  usually 
a  special  ganglion  for  the  nervous  supply  of  each  principal  organ  of  the  body. 
Such  a  multiplication  and  disposition  of  ganglia,  Oscar  Schmidt  endeavoured 
to  demonstrate  in  BracMonus  urceolaris  and  in  Hydatina  senta.  His  inter- 
pretation has,  however,  not  been  accepted  by  others,  and,  generally,  the 
characteristics  of  ganglions  are  so  ill-defined,  that  the  bodies  considered  to 
be  such  by  the  obsei^er  are  pronounced  to  be  no  other  than  vacuolar  thick- 
enings of  connective  or  other  dissimilar  tissue  by  others. 

Perty  makes  the  statement  that  in  Rydatina,  Synchceta,  and  Diglena  there 
is  a  series  of  ganglions  along  the  anterior  surface  of  the  abdomen,  with  con- 
necting nerve-fibres  between  them  and  the  brain.  A  nervous  system  of  this 
sort  belongs  to  the  higher  Crustacea  ;  but  although  many  have  sought  it  in 
the  Rotatoria,  Perty  is  the  only  observer  who  has  affirmed  its  existence  in  any. 


or  THE  KOTATOEIA.  437 

Mr.  Dalrymple  mentions  the  presence,  in  liis  Notomuiata  anylica,  of  a  small 
ganglion  sending  off  nerves  to  the  stomach,  salivary  glands,  and  ovary ;  but 
Leydig  looks  upon  this  structiu-e  as  no  more  than  the  cells  and  fibres  of  con- 
nective tissue,  and  states  that  "■  similar  clear  cells,  of  various  size,  having 
dehcate  elongated  branches,  are  seen  in  Notommata  centriira,  N.  Mi/nneleo, 
N.  davulata,  and  in  Diylena  lacustns.  The  delicate  branches,  or  threads, 
extend  between  the  epidermis  and  the  viscera  of  the  body,  and  were  described 
by  Ehrenberg  to  be  nerves,  but  are  actually  the  means  of  retaining  the  vis- 
cera in  situ,'^ — a  conclusion  supporting  that  of  Prof.  Williamson. 

There  is,  however,  one  set  of  nerves  recognized  by  most  observers,  which 
proced  from  the  cerebral  ganglion  to  the  surface  of  the  body,  ending  at  the 
bottom  of  the  epidermic  pits  described  above  (p.  408),  from  which  stiff  cilia  or 
bristles  project,  or,  otherwise,  running  to  the  extremity  of  the  protuberances 
and  antenna-like  processes,  Avhich  are  also  armed  with  bristles.  Daliymple 
noticed  nerves  so  disinbaiedm  Notommata  anylica  ;  and  Leydig  has  indicated 
the  like  in  many  species.  The  supply  of  a  nerve  to  the  so-called  siphon  or 
respiratory  tube  imparts  to  it  the  character  of  an  antenna,  tactile  organ,  or 
feeler.  The  evident  delicate  band  or  cord  seen  within  the  tubular  process  of 
Melicerta  is  indeed  called  by  Mr.  Williamson  a  muscular  band ;  yet  at  least 
some  portion  of  it  must  be  esteemed  a  nerve-cord,  if  the  organ  in  question 
really  possesses  tactile  powers. 

A  similar  distribution  of  nerves  is  witnessed  in  the  Turbellaria,  and,  as 
Leydig  says,  among  the  Phyllopoda  and  Arthropoda. 

Nei-vous  substance  has  its  origin  in  simple  cells,  which  in  ganglia  retain 
their  cellular  character,  but  in  nen^es  appear  to  be  elongated  as  tubes, — the 
ceU-wall  constituting  the  nerve-sheath  or  the  neurilemma — the  cell- contents 
(the  contained  nerve-tissue)  existing  as  a  fine  molecular  matter.  In  nerve- 
masses  or  ganghons  the  original  nuclei  remain,  and  the  several  constituent 
cells  are  aggregated  and  held  together  by  diffused  connective  tissue.  Some 
pecuHar  structures,  supposed  to  stand  in  especial  relation  to  the  nervous 
system,  are  described  by  Leydig.  We  cannot  do  better  than  follow  his 
account  in  an  abstract. 

Immediately  above  or  about  the  brain-ganglion,  in  many  genera,  a  sac  is 
observable  fiUed  with  a  whitish  substance,  called  by  Ehrenberg  the  "  chalk- 
sac  "  (Kalkbeutel).  Leydig  confesses  that  he  has  hitherto  been  unable  to 
determine  whether  this  sac  is  in  immediate  connexion  with  the  brain,  or  in- 
dependent of  it.  In  Notommata  centrura  (XXXYIII.  26  t)  it  appears  as  a 
process  or  lobe  of  the  brain;  but  in  another  species,  N.  aurita,  the  sac  is  so 
elongated  as  to  form  a  thin  stem  filled  with  the  chalk-like  matter,  which  it 
seems  to  discharge  by  an  opening  on  the  head.  This  organ  would  therefore 
seem  to  partake  of  the  nature  of  a  gland.  Beside  the  genera  named,  this  sac 
is  seen  in  Notommata  trijpus,  in  N  collans,  and  in  iV'  tardiyrada  ;  also,  if  the 
black  speck  noticed  by  Perty  be  the  same  structure,  in  N.  roseola.  Ehrenberg 
refers  to  its  existence  in  Diylena,  Meyalotrocha,  and  Brachionus ;  but  in  the 
last-named  genus  Leydig  has  failed  to  discover  it. 

The  vesicular  space  or  sac  is,  in  several  instances,  not  single ;  but  two, 
three,  or  four  are  noticeable.  Thus  in  Meyalotrocha  Ehrenberg  mentions  four 
opaque,  white,  spherical  bodies  at  the  base  of  the  rotary  organ. 

Another  sac,  distinct  from  the  foregoing,  is  seen  in  EiicJdanis  and  Notom- 
mata centrura,  lying  in  the  median  line  close  above  the  brain,  and  discharging 
itself  by  a  duct  passing  forwards  to  the  cuticle.  It  contains  no  chalky  matter, 
but  is  translucent  and  composed  of  clear  cells.  The  peculiar  and  considerable 
organ  which  Leydig  met  with  in  Stephanoceros,  placed  in  advance  of  the  sto- 
mach, and  consisting  of  a  group  of  hyaline  vesicles  with  a  discharging  orifice 


438  GENERAL  HISTORY  OF  THE  INFUSORIA. 

on  the  neck,  its  obseiTer  is  inclined  to  refer  to  the  same  category  with  the 
problematical  structui'es  of  Euclilanis  and  Notommata  centrura.  He  more- 
over seeks  to  establish  an  affinity  between  these  organs  and  the  small  clear 
space  sui'mounted  by  a  ring  on  the  cuticle,  situated  in  the  middle  line  of  the 
body,  behind  the  frontal  speck  in  Phyllopoda,  such  as  Branchipus  ;  but  even 
if  this  affinity  be  admitted,  no  light  is  thrown  upon  the  functions  of  these 
questionable  structures. 

b.  Organs  of  Sense. — The  existence  of  some  of  the  senses  is  to  be  in- 
ferred from  that  of  a  nervous  system.  The  sense  of  touch  is  one  concerning 
which  there  can  be  no  question ;  that  of  taste,  in  its  nature  allied  to  the 
tactile  sensibility,  is  very  doubtful,  whilst  those  of  smelling  and  heaiing  may 
be  pretty  safely  stated  to  be  entii-ely  absent.  Lastly,  the  sense  of  sight 
is  generally  admitted  to  exist,  and  to  have  special  organs,  or  eyes,  for  its 
exercise. 

Touch  may  be  supposed  to  be  diffused  as  common  sensibility  over  the 
entire  surface  of  the  body,  and  especially  developed  in  the  soft  tissue  of  the 
rotary  organ,  in  its  processes  and  antennae,  and  in  the  soft  processes  and 
termination  of  the  pseudopodium.  Something  approaching  a  sense  of  taste 
has  been  imagined  present,  particularly  in  the  antennae  or  feelers.  If  the 
faculty  of  hearing  seems  occasionally  exercised,  we  must  attribute  the  cir- 
cumstance in  part  to  the  perception  of  the  disturbing  cause  by  vision,  and  in 
part  to  the  vibrations  produced  in  the  hquid. 

The  visual  organs  (XXXVIII.  16-19,  33)  have  claimed  particular  atten- 
tion, and  now  have  their  existence  in  the  majority  of  Eotatoria,  at  some  pe- 
riod of  their  life,  satisfactorily  proved.  Dujardin,  dissatisfied  with  Ehrenberg's 
hasty  generalizations,  and  compelled  to  deny  the  visual  character  of  the  co- 
loured specks  in  various  Protozoa  and  Phytozoa,  looked,  no  doubt,  with  greater 
scepticism  upon  the  Berlin  Professor's  representations  of  eyes  in  Eotatoria 
than  he  othei-wise  would  have  done,  and  started  some  objections  against  them. 
He  says — "  I  wiU  not  deny  a  certain  analogy  between  the  red  specks  and  the 
colonized  points  observed  in  CydopidcB,  and  which  may  be  caUed  eyes ;  but  I 
cannot  assign  to  such  specks  a  very  high  importance,  seeing  that  they  con- 
stantly disappear  in  the  adult  condition  of  many  Rotifera,  and  otherwise  show 
themselves  more  distinctly,  according  to  the  degree  of  development  as  deter- 
mined by  the  season  and  the  place  of  development."  It  should  be  noted, 
however,  in  reply  to  this  objection,  that  a  similar  disappearance,  on  the  at- 
tainment of  the  adult  state,  occurs  in  the  parasitic  Crustacea,  the  visual  cha- 
racter of  whose  eye- specks  or  ocelli  is  not  questioned.  Moreover,  although 
some  coloured  specks  in  the  Rotifera  are  undoubtedly  mere  heaps  of  granules, 
yet  others  have  assuredly  a  definite  optical  organization  and  function.  These 
possess  a  refracting  medium,  the  essential  part  of  an  eye  ;  and  theii'  organ- 
ization, though  simple  and  imperfect,  yet  elevates  them  to  the  rank  of  eyes, 
eyelets,  or  oceUi. 

Ehrenberg  gave  much  attention  to  the  position,  nimiber,  and  other  pecu- 
liarities of  the  eye-specks  of  Rotatoria,  as  he  employed  them  largely  in 
framing  his  classification.  Unfortimately,  however,  he  cUd  not  acquaint  him- 
self sufficiently  with  their  minute  structiu'e,  but  was  content  to  call  all  the 
coloiu^ed  specks  he  met  with  eyes,  and  insisted  on  unimportant  and  inconstant 
particulars  as  generic  and  specific  characteristics.  These  errors  have  conse- 
quently much  vitiated  his  classification  {see  chapter  on  Classification) ;  and 
the  tendency  at  the  present  day  is  to  assign  to  the  coloiu'ed  eye-spots  an  al- 
together secondary  rank  among  the  characteristics  of  Rotatoria. 

Ehrenberg  described  the  eye- specks  as  variously  situated,  on  the  fore  part 
of  the  head  (forehead)  or  on  the  neck,  as  mostly  sessile  (?.  e.  situated  imme- 


OF  THE  ROTATORIA.  439 

diately  on  the  part),  and  rarely  pedunculate  (/.  e.  supported  on  a  pedicle  or 
Btem),  as  in  Otoglena.  In  some  species,  as  in  Rotifer,  the  eyes  are  placed 
on  a  protrusile  part  of  the  head,  and  consequently  appear  at  one  time  in  ad- 
vance of  the  head,  and  at  another  far  backward  mthin  the  body.  In  Monura, 
Ehrenberg  states  they  are  moveable.  The  number  of  eye-spots  varies  con- 
siderably :  in  several  genera  there  is  but  one,  e.  g.  Fiircularia,  3Ionocerca, 
Notommata,  and  Brachiomis  ;  but  two  eyes  are  more  common,  as  in  Melicerta 
(XXXYII.  15),  Lacinidaria,  Megahtrocha  (XXXII.  376),  Botifer  (XXXV. 
476-478),  and  Diglena  ;  three  eye-specks  occur  in  Asplanchna,  TriophthaU 
mus  (XXXIII.  412—414),  EospJiora,  and  Otoglena ;  four  in  SquameUa ;  and 
from  six  to  twelve  coloured  spots  and  upwards  are  met  with  in  Cydoglena  and 
Theorus  (XXXIY.  425-429),  but  their  visual  character  is  more  than  doubt- 
ful. These  last  "  conglomerate  eyes,"  as  Ehrenberg  calls  them,  appear  to 
be  no  other  than  collections  of  coloured  (it  may  be  oil)  particles,  and  are 
akin  to  the  large  coloured  spaces  seen  on  Notommata  forcipata  and  Synchceta 
Baltica,  having  neither  a  definite  nor  a  regular  outline  (see  p.  440).  Subse- 
quent research  has  proved  Ehrenberg  in  error  respecting  the  number  of  eyes 
in  several  species, — an  error  which  seriously  affects  his  classification. 

The  ordinary  colour  of  the  eye-specks  is  red,  but  sometimes  it  is  reddish- 
brown,  and  rarely  violet  or  black.  The  coloiu-  may  change  in  the  lifetime  of 
the  individual,  as  from  red  in  the  young  to  black  in  the  adult  state.  In  a 
few  instances  no  eye-specks  are  visible. 

Except  some  of  the  doubtful  collections  of  coloured  specks,  the  eye-spots  are 
placed  immediately  above  the  great  ganglion  of  the  head,  the  homologue  of  the 
brain,  or,  as  Siebold  affirms,  are  united  with  it  by  intermediate  nerve-fibres. 
The  intimate  structure  of  the  eyes  was  iU-understood  by  the  great  Prussian 
Professor.  He  was  unable  to  convince  himself  of  the  existence  of  a  cry- 
staUine  lens  and  of  a  cornea.  Thus,  in  his  account  of  Rotifer'  vulgaris,  he 
states  that  the  eyes  consist  of  several  cells  filled  with  a  granular  pigment, 
and  sometimes  they  separate  abnormally  into  several  portions.  He  thinks 
there  is  no  crystalline  lens,  although  they  are  probably  compound,  like  the 
eyes  of  insects. 

Siebold  insisted  on  the  coloured  specks  of  Rotatoria  being  sharply  defined, 
and  in  many  cases,  at  least,  furnished  with  a  capsule,  in  contradistinction  to 
the  ill-defined  vanishing  pigment-masses  imagined  to  be  eyes  in  the  Protozoa. 
Wagner  also  speaks  of  a  lens  in  the  eyes  of  Lacinularia.  Perty  is  adverse 
to  the  notion  of  a  lens  or  cornea,  or  of  a  capsule ;  yet  in  Pteivdina  Patina 
he  notes  that  the  elliptical  eye-speck,  viewed  on  the  side  and  from  below,  is 
seen  to  consist  of  an  upper  red  and  an  under  white  half.  That  the  latter 
represents  a  refracting  medium  is  highly  probable.  A  compound  structure 
is  further  indicated  by  Perty  in  Scaridium  longicaudum,  in  which  he  perceived 
'^  a  mass  of  small  granules  resembling  a  gland,  in  the  midst  of  the  red  pig- 
ment-corpuscles, which  are  outspread  irregularly,  and  paler  at  the  circum- 
ference. Moreover,  in  Euchlanis  triquetra  there  is  an  irregular  brown  scale 
with  reddish-brown  contents,  whilst  in  E.  Luna  the  unusually  large  eye-spot 
appears  to  be  made  up  of  ten  to  twelve  distinct  red  granules. 

^  Leydig  arranges  the  single  eye-specks  under  three  types : — 1.  an  ordinary 
pigment-spot,  of  a  rounded  or  irregular  outline,  a  reddish-brown,  black,  or 
\iolet  colour,  not  shar]^)ly  defined,  e.  g.  in  Notomynata  Synchceta ;  2.  a  de- 
fined, sharply-bounded  speck,  actually  composed  of  two  coalesced  hemi- 
spherical portions,  such  is  seen  in  Brachiomis ;  3.  a  speck  having  a  clear 
refracting  body  projecting  from  the  mass  of  pigment — a  stnicture  discovered 
by  Leydig  in  Euchlanis  unisetata  (XXXVIII.  19).  The  first  type  is  the  most 
prevalent. 


440  GENERAL  HISTOKY  OF  THE  INEUSOBIA. 

Leydig'  next  proceeds  to  show  that  the  single  eye-specks,  appearing  only 
as  an  accumulation  of  pigment- granules,  are  precisely  homologous  structures 
with  the  reputed  eyes  of  Cyclo;ps  and  Dajplinia  among  the  Entomostraca,  and 
of  Argulus,  Artemia,  and  Branchipus  among  the  Phyllopoda.  In  neither  the 
one  nor  the  other  does  a  lens,  cornea,  or  capsule  exist,  although  in  a  few  (for 
instance,  in  Notomiyiata  Myrmeleo)  a  gUstening  white  substance  is  intermixed. 
The  single  eye-spot  of  Brachionus,  with  its  coalesced  central  segments,  has 
its  counterpart  in  the  eye  of  the  larva  of  Cyclojps,  and  an  e\4dent  analogy 
with  that  of  Cychjysina,  as  also  with  that  of  Caligiis,  in  both  which  a  refract- 
ing lens  makes  its  appearance,  it  is  likewise  similar  in  general  conformation. 
Wh.o  then,  asks  Leydig,  can  advance  any  direct  arguments  against  the 
hypothesis  that,  by  the  medium  of  the  pigment-granules  in  immediate  con- 
tiguity with  the  nei-ve-cells  of  the  brain,  without  a  refracting  body,  a  percep- 
tion of  light  is  possible  ?  That  the  Rotatoria,  on  the  contrary,  may  possess, 
equally  with  the  Crustacea,  a  refracting  medium,  is  illustrated  by  the  example 
of  Euclilanis  unisetata.  With  reference  to  those  species  having  two  eyes,  Leydig 
has  convinced  himself  of  the  presence  of  a  lens  in  both  in  PterocUna,  Ste- 
phanops,  Metopidia,  Rotifer  citrinus,  and  in  R.  macrurus ;  and  he  thinks  he  has 
seen  one  in  the  eyes  of  the  young  of  Tuhkolaria,  Melicerta,  and  Stephanoceros, 
although  the  soft  state  of  the  parts  and  their  indistinct  outline  render  the 
observation  less  certain.  In  the  last-cited  animals,  when  any  trace  of  the 
eye-pigment  remains,  none  whatever  of  the  crystalline  lens  is  visible.  Of 
the  other  binocular  Rotatoria,  not  mentioned,  Leydig' s  opinion  is,  that  ana- 
logy intimates  the  existence  of  a  refracting  medium,  and  their  nature  as  true 
eyes.  The  presence  of  a  special  horny  skin  or  a  particular  capsule  sur- 
rounding the  pigment  is  doubtful ;  for  the  cuticle  probably  performs  the  office 
of  a  cornea. 

Of  the  many-eyed  Rotatoria,  Leydig  has  particularly  examined  Eosphora 
and  Theorus.  He  finds  Ehrenberg  in  error  respecting  Eosphom,  which,  in  fact, 
possesses  a  single  eye- speck  above  the  brain ;  and  what  that  natui'alist  took 
to  be  two  clear  eye-points  on  the  frontal  margin  are  merely  intensely  orange- 
or  yeUow- coloured  spaces,  which  are  at  once  seen  to  be  viithout  any  affinity 
with  the  other  eye-specks.  The  eyes  of  Theorus  are  nothing  more  than  oil- 
drops  within  the  stomach-glands.  Ehrenberg,  moreover,  describes  colourless 
eyes,  the  visual  nature  of  which  may  well  be  doubted.  Although  he  has  no 
direct  observation,  Leydig  believes  that  in  Squamella  the  pigment  is  composed 
of  numerous  portions  disposed  around  a  crystalline  lens,  and  that  the  animal 
may  consequently  be  called  many-eyed. 

The  conclusions  arrived  at  by  Leydig  are,  "  that  the  single-eyed  species  of 
Rotatoria  have,  many  of  them,  a  refracting  body  in  their  eye-specks,  which 
are  therefore  true  simple  eyes,  but  that  in  most  cases  a  lens  is  wanting,  and 
the  specks  are  merely  rudimentary  eyes ;  whilst  in  those  with  two  eye  spots, 
each  of  them  is,  by  the  presence  of  a  lens,  an  actual  simple  eye." 

Ehrenberg  stated  that  eye-specks  were  entirely  absent  in  several  genera : 
such  were  the  doubtful  Rotatoria  Ptygura  and  Ichihydium,  also  Chcetonotus, 
Cyphonautes,  Tuhicolaria,  Eiteroplea,  Hydatina,  Pleurotrocha,  LepadelUy 
Hydrias,  Typhlina,  and  Noteus.  With  reference  to  TuhicoUria,  Leydig 
shows  that  in  the  young  state  this  genus  has  two  eye-specks  ;  of  the  other 
exceptional  forms,  several  have  been  insufficiently  examined  to  found  any  cer- 
tain statements  upon. 

The  curious  fact  of  the  disappearance  of  the  eye- spots  in  several  Rotatoria 
has  been  already  referred  to.  Examples  occur  in  the  genera  Melicerta,  Laci- 
nularia,  Floscidaria,  Tubicolaria,  and  MegcdotrocJia. 

c.   The  Psychiccd  Endowments  of  Rotatoria  ai*e  probably  of  the  nature  of  in- 


OF  THE  ROTATOEIA.  441 

stiuct ;  some  so  supposed  are  simply  acts  dictated  by  external  circumstances. 
Perty  intimates  that  the  apparent  sinking  after  one  another,  the  gamboling 
among  themselves,  and  the  fact  of  their  depositing  theii'  eggs  in  chosen  and  ap- 
propriate localities,  to  which,  after  an  absence,  they  will  return,  are  pheno- 
mena evidencing  perception,  design,  and  a  sense  of  company.  This  last  imagined 
sense  was  one  suggested  by  Ehrenberg,  who  affirmed  that  he  had  observed  it 
in  the  case  of  Philodina  roseola,  which,  when  kept  in  glasses,  deposited  its 
eggs  in  heaps,  the  parent  remaining  a  long  time  with  the  young  ones  pro- 
duced from  them,  and  so  constituting  a  sort  of  family  or  colony, — an  act 
dictated,  as  he  sm^mised,  by  a  sense  of  company  or  family. 

The  occasionally-observed  rejection,  and  ejection,  of  what  may  be  deemed 
disagreeable  or  unsuitable  nutriment,  are  acts  which  some  might  interpret  to 
be  indicative  of  volition,  and,  in  some  degree,  of  pain  or  unpleasant  impression ; 
but  they  are  quite  explicable  without  reference  to  a  sentient  nei-ve- centre,  or 
to  high  psychical  endowments.  The  same  thing  may  be  said  of  other  reputed 
evidences  of  the  existence  of  psychical  or  mental  faculties. 

Of  the  Repeoductive  Organs  and  Development  of  Eotatoeia. — The 
Rotatoria  were  for  a  long  time  assumed  to  be  hermaphrodite  or  monoecious, 
?.  e.  that  each  individual  possessed  a  perfect  male  and  female  reproductive 
apparatus,  by  which  ova  are  formed,  and  fructified  without  the  presence  or 
contact  of  any  other  individual.  There  has  never  been  any  difficulty  in 
determining  the  female  generative  organs,  which  are  very  clear  and  well 
defined ;  but  the  greatest  diversity  of  opinion  has  subsisted  respecting  the 
coexistence  of  male  and  female  organs  in  the  same  individual. 

Dujardin  attempted  no  explanation  of  this  matter,  whilst  Siebold  candidly 
affirmed  that  in  the  absence  of  any  precise  knowledge  as  to  the  male  organs, 
it  is  impossible  to  say  whether  the  Rotatoria  are  monoecious,  or  have  the  sexes 
separate — are  dioecious. 

The  clearing  up  of  this  quest io  vexata,  in  several  at  least  of  the  Rotatoria, 
is  due  to  our  coimtryman  Sir.  Brightwell  of  Norwich,  who  demonstrated  the 
existence  of  distinct  male  animals,  and  figured  them  (XII.  Q5,  QQ)  in  his 
'  Fauna  Infusoria.'  This  discovery  was  further  carried  out  by  Mi\  Dal- 
rymple,  and  has  subsequently  been  extended  by  Mr.  Gosse,  Leydig,  and 
others.  Inasmuch,  however,  as  the  monoecious  or  hermaphi^odite  condition 
is  very  prevalent  among  the  lower  Invert ebrata  ;  as  the  males  of  the  majority 
of  the  Rotatoria  have  as  yet  escaped  detection  ;  and  as  there  are  parts  dis- 
cernible in  several  of  them  presenting  some  similarity  with  recognized  male 
organs  in  other  animals,  not  a  few  eminent  observers  still  incline  to  the 
belief  that,  at  least  in  a  portion  of  this  class,  the  sexual  organization  is  of  the 
monoecious  t}^3e.  These  doubtful  organs  wiU  be  discussed  after  the  well- 
determined  female  apparatus,  and  the  male  animals,  have  been  described. 

Female  Repeoductive  Oegans. — These  were  pretty  accurately  determined 
by  Ehrenberg,  who  noticed  a  single  or  double  ovary,  an  oviduct,  an  ovisac, 
and  a  vaginal  sheath  or  outlet  leading  to  the  cloaca  or  the  rectum. 

The  ovary,  in  which  the  ova  or  eggs  are  generated,  hes  immediately  beneath 
or  behind  the  alimentary  canal,  between  it  and  the  contractile  sac  (XXXVIII. 
26  0,  p ;  XXXYII.  le,  12  Ti,  32  c)  ;  its  anterior  border  often  advances  as  far 
forward  as  the  maxjUary  (oesophageal)  head.  Oftentimes  its  position  is  rather 
transverse,  and  it  lies  across  the  intestine,  or  is  curved  to  some  extent  around 
it.  It  varies  in  size,  but  is  always  a  very  large  organ,  and  occupies  a  consider- 
able space  in  the  interior  of  the  body.  It  also  presents  much  diversity  of 
figure,  being  sometimes  round,  oblong,  or  oval,  at  others  flattened,  elongated, 
reniform,  bilobed,  horned,  or  curved  like  a  horse-shoe.  It  is  enveloped  by 
a  dehcate  membrane,  rendered  verv  obvious  by  the   action  of  acetic  acid 


442  GENERAL  HISTORY  OF  THE  INFUSORIA. 

(XXXVII.  220),  which  contracts  the  substance  of  the  ovary,  and  throws  the 
membrane  into  sharp  folds.  This  membrane  may  likewise  be  detected  with- 
out the  assistance  of  chemical  reagents,  where  it  is  contracted  below  into  an 
outlet  or  duct  opening  in  the  cloaca.  It  forms  a  pellucid  membranous  bag, 
which  may  be  ruptm-ed  by  pressure,  giving  exit  to  its  viscid  contents ;  and 
Leydig  asserts  that  the  wall  of  the  ovary  is  contractile,  as  the  addition  of 
alcohol  demonstrates. 

The  substance  of  the  ovary  is  called  the  '  stroma '  or  protoplasm ;  it  has  a 
finely-granular  appearance  and  a  viscid  consistence.  It  is  usually  of  a  milky 
or  a  light-grey  colour,  and  has  interspersed  in  it,  besides  granules,  numerous 
clear  bodies  of  a  vesicular  appearance  (XXXYII.  1  e ;  XXXVII.  7),  but 
which,  Leydig  says,  are  reaUy  homogeneous.  Williamson  coimted  between 
20  and  30  in  the  ovary  of  Melicerta,  varying  in  diameter  from  ^^^,j^)th  to 
y-gifj-jjth  of  an  inch  (XXXVII.  22).  These,  by  development,  constitute  the  ova 
or  eggs,  and  may  be  termed  rudimentary  ova.  Within  each  a  finely-molecular, 
more  or  less  opaque,  and  rounded  body  is  perceptible  (the  nucleus),  siuTounded 
by  a  clear,  transparent  ring,  apparently  filled  with  fluid  (the  germinal  vesicle) 
(XXVII.  6,  7).  "  These  are,"  writes  Huxley,  ''  the  geiTtiinal  vesicles  and 
spots  of  the  fature  ova.  Acetic  acid,  in  contracting  the  pale  substance,  groups 
it  round  these  vesicles,  vtdthout,  however,  breaking  it  up  into  separate  masses. 
It  renders  the  nuclei  more  evident."  This  author  further  remarks,  '*the 
pale  clear  space  is  sometimes  seen  to  be  limited  by  a  distinct  membrane."  The 
measurements  of  the  nuclei  in  Melicerta  are,  according  to  Williamson,  from 
g  -^^  ^th  to  j-jij-jjth  of  an  inch  in  diameter.  Within  each  nucleus  are  usually 
from  one  to  thi'ee  clear  spots — the  nucleoli.  The  nucleolus,  as  understood  by 
Williamson,  corresponds  mth  the  nucleus  in  the  preceding  description,  whilst 
this  last  term  is  apphed  by  Huxley  to  the  entii'e  germinal  body  or  rudi- 
mentary ovum. 

Formation  oe  Ova,  their  Extrusion,  and  Development. — After  fructifi- 
cation, and  preparatory  to  their  transition  into  ova,  the  germinal  spaces  undergo 
various  changes  in  constitution  and  appearance.  The  germinal  vesicle  en- 
larges, its  nucleus  disappears,  and  the  ovum  is  indicated  only  by  an  ill- defined 
transparent  spot,  which  may,  by  pressure,  be  isolated  as  ^*  a  small  spherical 
cell  about  y^^y^th  of  an  inch  in  diameter,  having  very  thin  pellucid  walls, 
and  scarcely  any  visible  cell- contents  "  (Williamson).  Consentaneously  with 
these  movements  in  the  germinal  space,  the  construction  of  the  ovum  pro- 
ceeds by  the  attraction  and  separation  of  a  portion  of  the  surrounding  proto- 
plasm forming  a  yelk.  The  portion  so  appropriated  is  particularly  rich  in 
granules  which  have  previously  congregated  in  the  ovary,  and  now  attracted, 
it  may  be  supposed,  by  the  active  vital  action  set  up  in  the  rudimentary 
ovum.  This  abundance  of  granules  produces  a  deeper  colour  and  an  increased 
opacity  in  this  portion  of  the  ovary ;  so  that  when,  as  Prof.  Williamson  re- 
marks in  the  instance  of  Melicerta,  this  process  of  development  proceeds  in 
the  centre  of  the  ovary,  the  latter  organ  appears  divided  by  the  incipient  ovum 
into  an  upper  and  a  lower  half. 

The  consequence  of  these  several  changes  is  that  the  resultant  ovum  is  of 
considerable  size  (XXXVII.  170)  and  stands  prominently  outward  from  the 
general  surface  of  the  ovaiy,  acquiring  at  the  same  time  an  independent 
character  by  the  production  of  a  limiting  membrane  about  the  viteUus  or 
yelk,  called  the  vitelline  or  vitellary  membrane.  Huxley,  indeed,  does  not 
regard  this  as  a  distinct  and  specially  produced  covering,  but  as  derived  from 
a  portion  of  the  enclosing  membrane  of  the  ovary,  pinched  off  from  the  rest. 

Prof.  Williamson  enters  into  a  comparison  of  the  development  of  the  ova 
of  Melicerta  with  that  of  the  higher  Mammalia,  to  show  the  close  relationship 


OF  THE  ROTATORIA.  443 

that  subsists  between  them  during  this  process.  We  have  not  space  to  follow 
out  this  piece  of  comparative  physiology  in  the  words  of  the  author,  but  can 
only  state  his  conclusions :  viz.  that  the  elements  which  are  contained  in  and 
solely  occupy  the  ovisac  of  the  Melicerta,  are  those  which,  in  the  ovaries  of 
the  higher  Mammalia,  are  restricted  to  the  interiors  of  the  Graafian  vesicles  ; 
that,  whilst  in  the  former  the  protoplasmic  stock  forms  one  undivided  mass 
from  which  portions  are  successively  pinched  off  to  fonn  the  ova,  in  the  latter 
(the  Mammalia)  it  is  divided  into  small  portions,  each  being  contained  mthin 
a  special  receptacle  or  Graafian  vesicle,  the  interspaces  being  occupied  by  the 
stroma  or  tissue  of  the  ovarj-. 

It  is  in  the  yelk-matter,  derived  from  the  protoplasm,  that  the  red  tint 
noticed  by  Ehrenberg  and  others  occurs  ;  the  colour  depends  on  red  element- 
ary^ granules,  and  on  highly  refractive  oil-hke  particles.  Mr.  Gosse  suggests 
that  "  possibly  the  colouring  matter  of  these  reservoirs  may  be  resolved  into 
the  red  pigment  of  the  eyes,  and  the  yellow  of  the  jaw-cushion  and  other 
parts  ;  "  such  a  destiny  we  deem  scarcely  probable.  Moreover  the  ajDpear- 
ance  of  oil-molecules  often  refracting  a  red  colour,  about  parts  in  which  active 
development  is  proceeding,  is  a  fact  very  generally  observed.  A  red  hue  of 
the  ova  is  seen  in  PhUodina  roseola,  Bnicliioyius  ruhens,  Mastigocerca  carinata 
and  Polyartlira ;  in  Notommata  Sieholdii,  Asplancha,  Anurcea  curvicornis, 
Synchceta  jpectinata,  and  in  Lacinularia  socicdis.  Leydig  believes  that  in 
many  forms,  e.  g.  Brachionus,  Noteus,  and  Euchlanis,  one  portion  of  the  ovary 
produces  almost  exclusively  the  yelk,  and  has  in  consequence  a  darker  colour 
than  the  other  part,  which  developes  the  germinal  spaces.  This  phenomenon 
has,  he  remarks,  its  analogue  in  various  Crustaceans — the  Hexapoda  and 
Asellina.  It  may  be  here  stated,  however,  that  the  darker  portion  of  the 
ovary  has  assigned  to  it,  by  other  naturalists,  the  office  of  preparing  the 
winter  ova,  presently  described,  rather  than  the  yelk,  as  supposed  by  Leydig. 
The  preceding  account,  indeed,  applies  particularly  to  the  production  of  the 
ordinary  ova  ;  the  early  history  of  the  winter  ova  referred  to  will  be  given  in 
the  account  of  development. 

The  Ova. — The  Eotatoria  develope  two  varieties  of  eggs,  caUed  re- 
spectively "  summer  "  and  ''  winter  "  ova,  besides  male  eggs.  Much  difference 
obtains  between  them,  especially  in  their  developments,  contents,  and  later 
history.  The  summer  eggs  have  thin,  smooth,  firm,  and  elastic  shells,  so 
transparent  that  the  course  of  the  changes  proceeding  within  may  be  watched 
throughout.  In  figure  they  are  ellipsoid,  oval,  or  ovoid  (XXXVII.  5,  6,  8,  9). 
They  are  laid  by  the  animals  during  the  whole  coui^se  of  the  summer,  and  are 
forthwith  hatched.  The  winter  ova,  on  the  contrary,  are  chiefly  produced  in 
the  autumn,  and  are  destined  to  remain  in  an  inactive  or  torpid  state  during 
the  winter.  They  are  generally  of  larger  dimensions,  often  irregular  in  form, 
from  inequality  of  the  two  sides,  or  from  prominences  or  dej^ressions  of  the 
slufaces  (XXXIX.  20),  and  opaque  on  account  of  their  dark  granular  con- 
tents and  of  their  double  shell  (XXXYII.  21,  22,  24).  Caustic  potash 
renders  the  sheUs  clearer  and  more  transparent,  and  causes  some  of  the 
iillqualities  of  their  surface  to  decrease.  Huxley  says  that  the  tough  elastic 
membrane  or  sheU  is  soluble  in  both  hot  nitric  acid  and  caustic  potassa. 
Between  the  two  shells  is  an  interspace,  more  roomy,  at  the  opposite  ends  of 
the  egg.  The  inner  sheU  is  thin  and  delicate,  and  immediately  envelopes 
the  yelk  enclosed  in  its  vitelline  membrane.  The  external  one  is  thicker, 
firmer,  and  usually  of  a  brownish-yellow  colour.  Its  surface  is  mostly 
roughened,  or  tuberculated,  striated,  or  thrown  into  ridges,  areolated,  cellular, 
or  divided  into  facets,  beset  with  longer  or  shorter  hairs  and  bristles,  and  occa- 
sionally with  spines.     Examples  of  such  modifications  of  the  surface  occur  in 


444  GEIJEEAL  HISTORY  OF  THE  INFUSORIA. 

Anwcea  Testudo,  A.  serridata,  Notommata  Sieboldii,  N,  Myrmtleo,  Melicerta 
7'ingens,  Ascomorplia  Oermanica,  Lacinularia  socialis,  Scaridium  longicaudum, 
Hydatina  senta,  Anurcea  valga,  &c.  Ehrenberg  was  not  prepared  to  admit 
the  existence  on  ova  of  actual  hairy  processes,  but  supposed  them  to  be  the 
hair-like  filaments  of  Hygroerocis,  or  of  other  Algae.  This  supposition  may 
in  some  cases  be  correct ;  for  ova,  like  other  bodies  in  the  water,  may  become 
the  nidus  for  the  growth  of  various  microscopic  plants  and  animals.  That 
some  ova,  however,  are  actually  hairy  is  evidenced  by  their  visible  occuiTence 
in  that  state  even  whilst  still  within  the  abdomen  of  the  parent ;  as  may  be 
seen  in  the  ova  of  Hydatina  senta,  of  Notommata  Parasitiis,  &c.  Both  winter 
and  summer  ova  may  often  be  met  with  in  the  same  animal  (XXXIX.  16) — 
the  one  kind  perhaps  still  in  the  ovary,  the  other  on  the  point  of  expulsion  ; 
or,  it  may  be,  both  sorts  may  be  carried  about  attached  to  the  posterior  part 
of  the  parent  animal.  This  last  occurrence  is  noticed  by  Leydig  in  Brachionas 
Baheri, 

These  two  varieties  of  ova  were  recognized  by  Ehrenberg,  who  assigned 
them  the  names  applied  to  them.  Mr.  Huxley  suggests,  instead  of  the  term 
<  winter  ova,'  the  appellation,  '  ephippial '  ova,  to  indicate  their  analogy  with 
the  similar  eggs  of  Daphaia  and  other  Entomostraca. 

When  recounting  the  propagation  of  Notommata  Sieboldii,  Leydig  remarks 
that  male  and  female  ova  are  not  developed  together  in  the  same  animal. 
This  fact  has  been  extended  by  Cohn  to  apply  to  the  whole  family  of  Rota- 
toria. According  to  him  the  ephippial  are  always  distinguishable  by  their 
external  characters  from  the  common  summer  ova,  particularly  by  their  much 
smaller  dimensions.  They  have  thin,  transparent  shells,  and  are  chiefly  pro- 
duced at  those  seasons  when  '  ephippial '  ova  are  generated.  Their  develop- 
ment follows  the  same  course  as  that  of  the  '  summer  '  ova ;  but  they  are  pro- 
duced in  very  much  smaller  numbers, — a  circumstance  that  affords  another 
reason  for  the  paucity  of  males  compared  with  females,  whenever  a  collection 
of  Rotatoria  is  examined. 

When  the  development  of  summer  ova  in  the  ovary  has  proceeded  to  the 
point  we  have  mentioned,  and  the  egg  is  already  become  a  distinct  body  from 
the  general  substance  of  the  ovary  (XXXYIT.  2  d),  it  is  slowly  moved  down- 
wards towards  the  passage  or  o\iduct  (XXXVII.  2/),  which  ends  in  the 
cloaca  (XXXYII.  32  d) ;  and  it  is  in  this  part  of  its  course  that  the  shell 
becomes  perfected.  In  the  majority  of  the  Rotatoria  the  ova  are  at  this  stage 
extruded,  the  further  phases  of  development  proceeding  externally  to  the 
animal ;  in  others  they  are  detained  in  their  passage  until  the  embryo  is 
more  fuUy  elaborated,  or  even  until  it  is  perfect  and  released  from  its  shell. 

The  size  of  the  ova  prior  to  expulsion  XXXVII.  32  d;  XXXYIII.  26p) 
is  very  extraordinary,  so  much  so  that  a  single  ovum  will  sometimes  occupy 
the  larger  portion  of  the  interior  of  the  animal.  The  completed  egg  of  Me- 
licei'ta.  has  an  average  length,  says  Williamson,  of  y^-yth  of  an  inch,  and  a 
diameter  of  yfo^^-  -^^®  ^SS^  ^^  some  Hydatince  are  -g-g-g^-'^'  ^^  Lacinularia 
■j^th  of  an  inch  and  upwards  in  diameter. 

In  several  Rotatoria,  two  or  more  ova  become  agglutinated  together  n^r 
the  termination  of  the  oviduct,  or  in  the  cloaca,  and  are  expelled  together  en 
■masse,  and  still  remain  adherent  to  the  parent,  close  to  the  cloacal  outlet  at 
the  base  of  the  tail.  This  is  exempHficd  in  Triarthra  (XXXYIII.  30  d),  Po- 
lyarthra  (XXXIII.  400,  401),  Anurma  (XXXY.  496;  XXXIX.  16),  and 
Noteus. 

The  oviduct,  or  passage  from  the  ovary  to  the  cloaca,  is  a  membranous  tube 
formed  by  a  prolongation  of  the  tunic  of  the  ovary.  It  is  always  extremely 
dilatable ;  and  sometimes  an  egg  is  so  long  detained  in  its  lower  part,  that  it 


OF  THE  ROTATOKJA.  445 

seems  to  serve  the  purpose  of  a  uterus,  and  has  received  the  name  of  ovisac. 
The  orifice  of  this  oviduct  or  ovisac  into  the  cloaca  is  called  the  "  vaginal 
orifice ; ''  the  vaginal  sheath,  spoken  of  by  Ehrenberg,  would  appear  to  be 
either  the  termination  of  the  oviduct  or  sometimes  the  cloaca  itself.  The 
o\iduct  may  occasionally  be  deficient.  Prof.  Huxley  states  that  he  could 
discover  no  such  passage  in  Lacinularia. 

The  egg,  having  descended  into  the  cloaca,  is  expelled  thence  by  means  of 
a  strong  contraction  of  the  whole  body,  and,  in  the  act  of  escaping,  involves 
the  eversion  of  the  cloaca.  The  time  occupied  in  the  formation  of  the  sum- 
mer egg,  from  its  first  appearance  as  a  vesicular  space  in  the  ovary  to  its 
completion  and  extnision,  is  very  brief,  generally  only  a  few  hours. 

AYe  have  noted  the  discharge  of  several  eggs  adherent  together,  and  their 
subsequent  attachment  at  the  anal  outlet.  In  other  Rotatoria,  likewise,  ova 
expelled  singly  attach  themselves  at  the  posterior  extremity  of  the  body, 
singly  or  united  together  by  a  gelatinous  matter,  and  not  uncommonly  at- 
tached by  evident  cords  or  pedicles  to  the  parent.  This  is  seen  in  Megalo- 
trocha,  in  Brachionus  ruhens,  and  in  B.  Pala. 

In  the  species  last  named,  as  many  as  ten  may  often  be  seen  in  a  group 
near  the  cloacal  orifice.  In  AscomorpTia,  some  six  may  be  found  adherent. 
In  Polyarthra  (XXXVIII.  30),  not  more  than  one  egg  is  found  attached  at  the 
same  time.  Thus  the  eggs  are  carried  about  by  the  parent  one  after  another, 
arriving  at  maturity  and  escaping  from  its  shell.  The  like  phenomenon  is  seen 
in  various  Entomostraca,  and  in  Polynoe,  Exogona,  and  other  Vermes,  which 
likewise  produce  both  summer  and  winter  ova.  Among  the  urceolate  Ro- 
tifers, the  eggs  escape  into  the  case  or  gelatinous  investment,  and  there  pro- 
ceed to  their  ultimate  development,  safe  from  many  obnoxious  infiuences  and 
from  destruction  by  other  animals. 

Development  of  the  Embryo.  —  The  following  changes  transpire  pre- 
paratory to  the  construction  of  the  embryo.  The  nucleus  is  seen  to  elongate, 
and  then  to  present  a  constriction  about  its  middle  (XXXVII.  5)  ;  the  yelk 
at  the  same  time  shows  a  similar  constriction,  which  continues  to  deepen  in 
correspondence  with  that  of  the  nucleus,  until  at  length  there  are  two  seg- 
ments, each  with  its  contained  nucleus — the  result  of  the  fission  of  the  primary 
one.  Leydig  states  that  this  division  is  not  into  two  equal  portions,  but  that 
a  segment  is  cut  off  from  one  end  or  pole  (XXXVII.  2  h),  and  that  in  the 
continued  segmentation  which  ensues,  this  same  unequal  fission  is  again 
and  again  repeated.  However  this  may  be,  the  act  of  division  goes  on 
(XXXVII.  8)  until  at  length  the  whole  yelk  is  broken  up  into  a  mass  of 
minute  cells,  and  its  opacity  increased  by  the  number  of  molecules  they  con- 
tain (XXXVII.  2  c,  g).  Out  of  this  mass,  the  tissues  and  organs  of  the  em- 
bryo are  developed,  appearing  in  their  characteristic  forms  without  any,  or 
otherwise  very  slight,  transitional  phases  (XXXVII.  2e,d;  XXXVIII.  9). 
It  is  characteristic  also  of  Rotatoria,  in  common  with  all  the  Vermes,  that 
the  embryo  is  generated  from  the  entire  yelk,  and  not,  as  in  Crustacea  and 
stiU  higher  animals,  from  an  accessory  body  superposed  upon  the  yelk,  into 
which  the  yelk  is  gradually  taken  up.  Dr.  Carpenter  remarks  that  the  mode 
of  development  is  in  all  essential  respects  the  same  as  that  of  the  Xematoid 
Entozoa,  each  group  of  ceUs  evolving  some  one  principal  organ. 

The  order  of  succession  of  the  parts  of  the  embryo  in  the  egg  is  thus  de- 
scribed by  Ehrenberg  in  the  instance  of  the  Megalotrocha  alho-flavicans  : — 
"  A  turbid  central  spot  appears,  which  becomes  the  oesophageal  bulb  and 
teeth ;  a  blackish  granular  oval  body  is  also  seen  posteriorly  ;  the  eyes  gra- 
dually become  red,  and  a  motion  of  the  cilia  of  the  head  is  visible  ;  after  some 
hours  the  whole  foetiLs,  which  is  folded  up,  turns  itself  round,  the  shell  bursts, 


446  GENERAL  HISTORY  OF  THE  INFUSORIA. 

and  the  young  animal  creeps  out."  In  a  specimen  of  Brachionus  Baker i  the 
first  thing  Mr.  Brightwell  detected  was  a  motion  like  that  of  the  muscular 
oesophagus  of  the  parent. 

The  best  account  we  have  of  the  subject  is  that  given  by  Prof.  Williamson 
of  the  Melicerta  ringens  : — "  The  first  trace,"  he  says,  "  of  futm-e  organiza- 
tion which  presents  itself,  appears  in  the  form  of  a  few  freely  moving  cilia 
....  at  two  points,  one  of  which  corresponds  with  the  future  head,  the  other 
near  the  centre  of  the  ovum ....  with  the  cavity  of  the  stomach ;  shortly 
after ....  traces  of  the  central  parts  of  the  dental  apparatus  present  them- 
selves, this,  again,  being  soon  succeeded  by  the  union  of  the  entire  mass  of 
yolk-cells,  and  the  formation  from  them  of  the  various  organs  of  the  animal. 
The  ciHa  now  play  very  freely,  especially  at  the  head.  The  creatm^e  twists  itself 
about  in  its  shell ;  two  red  spots  appear  near  the  head,  which  Ehrenberg  re- 
gards as  organs  of  vision,  and  along  with  them  a  very  dark-brown  and  some- 
what larger  spot  is  developed  in  the  integument  near  the  lower  stomach. 
The  young  animal  now  bursts  its  shell ; .  .  .  .  and  although  its  external  ap- 
pendages (XXXYII.  15),  and  especially  the  rotatory  organs  are  imperfectly 
developed  or  unexpanded,  yet  the  whole  of  its  internal  organization,  though 
but  obscurely  seen,  is  nevertheless  that  of  the  perfect  animal,  and  not  that  of 
the  larval  state." 

In  the  embryo  animal,  whilst  ^\athin  the  egg  (XXXYII.  2  h),  as  well  as 
for  a  short  time  after  its  escape  (XXXYII.  3,  4  6),  Leydig  finds  in  most  Eo- 
tatoria  the  collection  of  black  or  dark-brown  particles  close  upon  the  cloaca 
(XXXYIII.  7,  8,  9),  which  has  been  described  in  the  section  on  Secretion, 
as  a  supposed  mass  of  urinary  concretions. 

The  period  occupied  in  the  development  of  the  embryo  differs  in  different 
species.  Ehrenberg  stated  that  in  Hydathia  senta,  eleven  hours  after  the 
deposition  of  a  complete  ovum,  vibration  of  the  anterior  ciha  was  \isible,  and 
in  24  hours  the  young  being  escaped  from  its  shell.  Mr.  Brightwell,  in  his 
notice  of  Brachionus  Baheri,  states  that  ^'  about  2  o'clock  the  animal  was  ob- 
served Avith  one  egg  placed  externally  between  the  two  posterior  spines  of 
the  shell,  and  another  small  egg  in  the  left  side  of  the  animal,  which  increased 
much  in  size  in  the  course  of  the  day ;  at  9  in  the  evening  a  motion  was  per- 
ceived in  the  exterior  egg  like  that  of  the  muscular  oesophagus  of  the  parent ; 
and  about  this  time  the  internal  egg  was  protruded  and  placed  by  the  side  of 
the  other,  being  longer  than  it.  At  11  the  young  BracJiionus  burst  with  a 
boimd  from  the  egg  in  which  the  motion  was  perceived,  and  affixed  itself  by 
its  tail." 

The  egg-shell  splits  open,  longitudinally  or  transversely,  to  give  exit  to  the 
young  animal.  This  seems  brought  about  by  the  active  movements  of  the 
embryo  itself,  which  sometimes  bursts  (as  Brightwell  says)  with  a  bound  or 
spring  from  its  prison.  Where  the  eggs  have  been  attached,  the  empty  fissured 
shell  continues  still  adherent  for  a  time,  until  by  the  movements  of  the  parent, 
or  by  some  accident,  it  is  detached. 

The  variation  among  different  Eotatoria  in  the  stage  of  development  in 
which  the  ovum  is  found  when  it  quits  the  ovary,  or  when  it  is  expelled  from 
the  body,  has  been  ah-eady  remarked ;  but  additional  illustrations  are  desira- 
ble. In  the  greater  number,  the  egg  is  laid  just  before  or  very  soon  after 
the  process  of  segmentation  of  the  yelk  commences ;  for  example,  in  3feU- 
certa,  Lacinularia,  and  Brachionus.  In  many  genera  the  ovum  continues  in 
the  oviduct,  the  ovisac,  or  the  cloaca,  or  otherwise  remains  within  the  ovaiy 
itself  until  the  embryo  is  complete  and  even  free.  Examples  of  this  are  found 
in  Stephanoceros,  Actinurus,  in  Rotifer,  and  in  Notommata  Syrinx,  N.  Sie- 
holdii,  and  in  Asplanclina.     In  Rotifer,  Ehrenberg  remarks  that,  in  the  ova- 


OF  THE  ROTATOHIA,  447 

riurn,  foiu'  or  five  ova  sometimes  so  completely  develope  themselves,  that  the 
young  creep  out  of  theii'  envelopes,  in  which  they  vrere  coiled  up  in  a  spii^al 
manner,  extend  themselves,  and  put  their  wheels  into  motion  while  within 
it ;  and  they  sometimes  occuj^y  two-thii'ds  of  the  bulk  of  the  parent.  So 
Mr.  Gosse  tells  us  that  in  AsjpJanclma  ''  the  o^Tim  produces  the  living  young 
in  the  ovisac,  which,  when  matured,  occui)ies  the  whole  lower  part  of  the 
parent."  The  occuiTcnce  of  embryos  free  within  the  saccular  ovary  of  Ste- 
phaiioceros  (and  still  more,  if  as  some  have  thought,  they  detected  them  loose 
in  the  general  cavity  of  the  body)  forms  another  bond  of  affinity  between  this 
aberrant  genus  of  Eotatoria  and  the  Bryozoa.  Where  the  young  in  general 
quit  the  parent  in  a  free,  and  so  far  perfect  form  as  to  be  able  to  lead  at 
once  an  independent  existence,  the  animals  may  be  said  to  be  viviparous 
(producers  of  li^-ing  yoimg).  This  viviparousness  (viviparity)  is  still  more 
pronounced  in  some  Philodincea  and  in  Alhertia,  in  which  the  formation  of 
an  actual  egg-shell  seems  to  be  omitted,  and  the  developed  embryo  to  be  at 
once  Hberated  within  the  sac  of  the  ovary,  where  it  may  be  seen  in  active 
movement. 

The  Embryo  Metamorphosis. — It  has  already  been  remarked,  generally, 
that  the  embryo  on  emerging  from  the  e^^  has  all  the  characters  of  its  class, 
and  is  complete  in  its  internal  organization  ;  that  any  dissimilarity  between 
the  new-born  and  the  adult  animal  is  due,  not  to  the  absence  of  parts  or 
organs,  but  to  their  lesser  growth  and  their  imperfect  expansion  or  evolution. 
In  other  words,  the  Rotatoria  undergo  no  positive  metamorphosis ;  they  j^ass 
thi'ough  no  intermediate  phases  of  existence,  no  larval  form  resembhng  that 
of  any  Protozoa,  in  advancing  from  the  embryonic  to  the  complete  and  per- 
fect condition. 

Leydig  does  not  partake  this  opinion,  but  thinks  that  a  metamoriDhosis  is 
exhibited  in  the  course  of  development  of  most  or  all  Eotatoria,  certainly  not 
complete,  but  still  sufficient  to  advance  it  as  a  phenomenon  of  the  class.  He 
specially  adduces  the  instance  of  the  embiyo  of  Stephanoceros,  as  the  most 
striking  proof  (XXXYII.  3,  4),  and  he  adds  that,  if  the  representation  by 
Ehrenberg  of  the  young  of  Triarthra  Jongiseta  be  correct,  the  fact  of  a  meta- 
morphosis must  be  recognized  also  in  that  genus.  Again,  he  notes  the  great 
difference  between  the  newly-bom  and  the  adult  animals  in  several  genera, 
e.  g.  in  Tuhicolaria  and  Melicerta,  where  the  cihary  wi^eath  is  still  very 
simple,  and  the  absence  of  the  tentacles  (antennaD)  sufficiently  notable 
(XXXYII.  15)  to  render  the  subsequent  modifications  an  act  of  metamor- 
phosis. Moreover,  the  disappearance  of  the  bunch  of  ciha  in  the  young  state 
at  the  end  of  the  pseudopodium,  and  lilvewise  that  of  the  coloui^ed  eye-specks 
in  many  genera,  when  the  adult  condition  is  attained,  are  also  indications  of 
the  same  phenomenon. 

The  advocacy  of  this  opinion  was  especially  incumbent  upon  Leydig,  in 
order  to  furnish  an  additional  argument  in  favour  of  the  affinity  of  the  Eota- 
toria with  the  Crustacea.  But  even  w^re  the  evidences  of  metamorphosis 
among  the  Eotifera  as  complete  as  he  represents,  they  would  serve  his  pur- 
pose, of  demonstrating  the  affinity  he  advocates,  but  Httle,  seeing  that  the 
immature  Eotatoria  have  no  real  resemblance  to  the  larval  Crustaceans  with 
their  three  pairs  of  jointed  feet.  Cohn  (Siebold's  Zeitschr.  1855,  p.  481)  has 
discussed  this  question,  and  surmises  that  the  peculiar  embryo  of  Stephano- 
ceros,  which  Leydig  cites  as  the  strongest  instance  of  an  act  of  metamor- 
phosis, is  a  male  being  (XXXYII.  3).  As  to  the  other  supposed  instances, 
Cohn  disproves  its  occurrence  in  Brachionus,  and  considers  the  disappearance 
of  the  eye-speck  in  Tuhicolaria  and  Melicerta  too  trivial  a  circumstance  to 
urge  in  its  support. 


448  GENERAL  HISTORY  OF  THE  INFUSORIA. 

Perty  seems  struck  by  the  considerable  variations  in  form  between  many 
embryo  and  adult  Rotatoria,  and  enunciates  the  opinion  that  many  supposed 
perfect  forms  are  no  other  than  embryonic  conditions, — for  example,  GJeno- 
'phora  Trochus,  Monocerca  vcdga,  Notoimnata  Felis,  and  CydogUna  elegans. 
We  do  not  understand  whether  he  believes  in  a  metamorphosis,  or  if  he 
would  simply  state  that  Ehrenberg  unnecessarily  multiplied  genera  and  spe- 
cies by  describing  immatm-e  beings  as  distinct  forms.  If  the  latter  be  all 
that  Perty  intends,  we  entirely  concur  ^\ith  him. 

It  is  necessary  to  detail  the  form  and  structure  of  some  embryo  Rotifera, 
to  illustrate  the  preceding  statements.  The  embryo  of  Stephanoceros 
(XXXVII.  3,  4)  is  thus  described  by  Leydig : — "  It  has  in  general  a  vermi- 
cular figui-e.  The  head,  which  supports  the  eyes,  is  separated  from  the  trunk 
by  a  well-marked  constriction,  and  is  furnished  with  long  cilia.  The  head 
and  cilia  are  retractile.  The  red  specks  (two  in  number)  appear  actually  to 
be  of  the  natiu'e  of  eyes  ;  they  have  a  sharp  outline  and  are  slightly  concave 
in  front,  as  if  a  refracting  body  was  there  seated.  Within  the  abdominal 
cavity  behind  the  head,  a  peculiar  striation  is  observable,  the  purpose  of 
which  I  cannot  imagine ;  further  backward  is  a  clear  space  in  which  long 
cilia  are  seen  in  activity,  and  which  indicates  the  cavity  of  the  alimentary 
canal.  Moreover,  the  maxillary  apparatus,  and  the  special  vesicle  containing 
the  inorganic  particles  (uiinary  concretions)  are  perceptible.  The  termina- 
tion of  the  body  bears  some  deKcate  vibratile  cilia."  Beyond  this  phase  of 
development,  the  embryo  does  not  advance  in  the  egg,  but  after  being  hatched, 
it  would  seem  to  assume  another  intermediate  fomi  before  arriving  at  the 
adult  state.  Leydig  found,  in  water  containing  Stephanoceros,  a  yoimg 
animal  still  possessing  in  some  measure  the  previous  vermiform  figure  and 
apparent  articulation  of  the  trunk  and  foot,  and  a  proboscis-like  head  with 
four  projecting  arms.  The  eye-specks  were  still  present.  From  the  trunk- 
like process  of  the  head,  two  considerable  tubular  appendages  were  out- 
stretched, ciliated  at  the  extremities :  the  cilia  on  the  end  of  the  foot-process 
had  disappeared,  but  were  very  evident  in  the  abdomen,  near  to  the  sac  con- 
taining the  inorganic  particles.  The  mandibular  apparatus  had  the  regular 
stmcture.  He  frequently  encountered  also  another  variety,  which,  together 
^dth  the  figure  of  the  perfect  animal,  had  five  arms,  but  was  without  any 
apparent  sexual  organs,  while  the  foot-process  and  the  w^hole  body  were 
strewn  with  numerous  fat-globules. 

We  will  now  continue  the  description  (see  p.  446),  by  Prof.  Williamson,  of 
the  embrj'o  of  Melicerta  after  escaping  the  egg-shell.  He  writes — "  The 
young  Melicerta  stretches  itself  out,  and,  everting  the  anterior  part  of  its 
body,  unfolds  several  small  projecting  mammillae  covered  with  large  cilia,  by 
means  of  which  it  floats  freely  away  (XXXVII.  15,  16).  These  mammillae 
are  in  this  stage  not  unlike  those  of  Notommata  clavidata,  but  they  soon  en- 
large and  become  developed  into  the  flabeUiform  wheel  organs  of  the  mature 
animals.  The  dental  apparatus  is  now  fully  developed ;  the  alimentary  canal 
and  muscular  fasciculi  are  all  present, — only  the  epithelial  cells  of  the  former 
have  not  as  yet  obtained  theii'  yellow  granular  contents ;  consequently  the 
viscera  exhibit  the  same  hyaline  aspect  as  the  rest  of  the  organism.  The  two 
red  specks  are  imbedded  in  two  of  the  mammillae.  After  swimming  about 
for  some  time  like  other  free  Rotifera,  the  animal  imdergoes  further  changes. 
The  dark-brown  spot  is  the  first  to  disappear ;  and  soon  after,  the  two  pink 
ones  cease  to  be  \asible.  The  animal  attaches  itself  by  the  tail  to  some  fixed 
support,  and  developes  from  the  skin  of  the  posterior  portion  of  its  body  a 
thin  hyaline  cylinder,  the  dilated  extremity  of  which  is  attached  to  the  sup- 
porting object.     The  formation  of  the  case  is  now  begim  ;  the  first-formed 


OF  THE  ROTATORIA.  449 

spheroidal  or  tentacular  particles  are  arranged  in  a  ring  round  the  middle  of 
the  body,  and  appear  to  have  some  internal  connexion  with  the  thin  mem- 
branous cylinder.  At  first,  new  additions  are  made  to  both  extremities  of 
the  enlarging  ling ;  but  the  jerking  contractions  of  the  animal  at  length  force 
the  caudal  end  of  the  cylinder  down  upon  the  leaf,  to  which  it  becomes  se- 
cui-ely  cemented  by  the  same  viscous  secretion  as  causes  the  little  spheres  to 
cohere.  All  the  new  additions  are  now  made  to  the  free  extremity,  which, 
as  Ehrenberg  remarks,  never  extends  beyond  the  level  of  the  cloacal  aper- 
ture of  the  outstretched  animal.  In  the  new-born  being,  therefore,  the  parts, 
as  in  the  adult,  are  all  present ;  they  only  require  to  be  expanded  by  the 
ordinary  process  of  growth." 

Mr.  Gosse's  account  of  a  newly-hatched  Melicerta  implies  a  greater  aber- 
ration of  form  than  that  narrated  by  Prof.  Wilhamson.  He  states  that 
"  its  form  is  trumpet- shaped  like  that  of  Stentor,  with  a  wreath  of  cilia 
aroimd  the  head,  internipted  at  two  oj^posite  points.  The  central  portion  of 
the  head  rises  into  a  low  cone."  After  various  movements  and  gp^ations  for 
an  hoiu',  the  young  animal  settled  itself,  and  the  form  of  the  adult  became 
manifest :  "  the  four  petals  of  the  disk  were  well  made  out,  though  the  sinu- 
osities were  yet  shallow  ;  the  antennae  at  first  were  only  small  square  nipples, 
but  soon  shot  out  into  the  usual  form  ;  the  ciliated  chin  was  distinct,  as  was 
also  the  whirling  of  the  pellet-cup  immediately  beneath  it." 

We  are  indebted  to  Mr.  Huxley  for  an  elaborate  description  of  the  young 
of  Lacinularia  sociaUs  (XXXYII.  10,  11).  ^' The  youngest  foetuses,"  he 
writes,  "  are  about  T^j-th  of  an  inch  in  length.  The  head  is  abruptly  trun- 
cated, and  separated  by  a  constriction  from  the  body ;  a  sudden  narrowing 
separates  the  other  extremity  of  the  body  from  the  peduncle,  which  is  ex- 
ceedingly short  and  provided  with  a  ciliated  cavity,  a  sort  of  sucker,  at  its 
extremity.  The  head  is  nearly  cii'cular  seen  from  above,  and  presents  a  central 
protuberance,  in  which  the  two  eye-spots  are  situated.  The  margins  of  this 
protuberance  are  provided  mth  long  cilia ;  it  will  become  the  upper  circlet 
of  cilia  in  the  adult.  The  margin  of  the  head  projects  beyond  this,  and  is 
fringed  with  a  circlet  of  shorter  cilia  in  the  adult.  The  internal  organs  are 
perceived  with  chfficulty ;  but  the  three  divisions  of  the  alimentary  canal, 
which  is  as  yet  straight  and  terminates  in  a  transparent  cloaca,  may  be 
readily  made  out.  The  water-vascular  canals  cannot  be  seen  ;  but  their  pre- 
sence is  indicated  by  the  movement  of  their  contained  cilia  here  and  there. 

'"  In  young  Lacinidarice  ^ih  of  an  inch  in  length,  the  head  has  become 
triangular  ;  the  peduncle  is  much  elongated,  and  it  gradually  takes  on  the 
perfect  form.  The  young  had  pre\iously  crept  about  in  the  gelatinous  in- 
vestment of  the  parents;  they  now  begin  to  "swarm,"  uniting  together  by 
their  caudal  extremities,  and  are  readily  pressed  out  as  united,  free,  swim- 
ming colonies,  resembling  in  this  state  the  genus  Conochilas.''' 

Mr.  Brightwell  gives  the  appended  brief  account  of  the  BmcMonus  Baheri 
on  its  escape  from  the  egg  : — '-At  first  it  had  the  appearance  of  an  oblong 
ball ;  by  degrees  the  anterior  part  spread,  and  the  wheel  processes  were  de- 
veloped. Soon  after,  the  posterior  shell  (lorica)  processes  were  visible  in  a 
semilunar  shape,  with  the  points  nearly  touching  each  other,  which  gradually 
expanded." 

These  examples  are  sufficient  to  illustrate  the  general  character  of  embryo 
Rotatoria  and  their  progressive  assumption  of  the  adult  form  ;  they  more- 
over furnish  evidence  of  the  doctrine  that  there  is  no  metamorphosis,  or 
transformation,  in  the  proper  sense  of  the  word — no  change  but  what  is  expli- 
cable by  the  ordinary  laws  of  growth,  or  progressive  expansion  or  evolution. 
Ehrenberg  has  announced  it  as  a  fact  {Monatsh.  d.  Berl.  Alrid.  1853,  p.  532), 


450  GENERAL  HISTOTlY  OF  THE  rjfFUSOKlA. 

that  Rotifera  found  at  great  altitudes  among  snow  do  not  attain  a  complete 
development,  but  retain,  as  he  expresses  it,  an  ovate  contracted  figure  ^dthin 
an  egg-like  envelope  or  capsule,  through  which  food  reaches  them  by  a 
funnel-shaped  canal.  All  the  functions  of  life  he  represents  to  go  on  as 
usual  under  these  peculiar  conditions  of  existence,  including  the  deposition  and 
hatching  of  eggs.  This  account  reads  like  a  description  of  an  encysting- 
process  in  the  first  degree — that,  viz.,  for  self-defence  and  preseiTation — 
such  as  is  illustrated  in  the  formation  of  an  open  sheath  around  Stentor,  as 
stated  by  Cohn  (see  p.  284). 

Contents  and  Development  of  Winter  Ova. — The  contents  of  "  winter  " 
widely  difier  from  those  of  '^summer  "  ova.  Mr.  Gosse  gives  the  follomng 
account  of  those  of  Melicerta  rinc/ens.  He  writes — "  Opening  one  or  two 
cases  (urceoli),  I  find  one  and  another  very  curious  egg-like  bodies,  not  sym- 
metrical in  shape,  being  much  more  gibbous  on  one  side  than  the  opposite, 
and  measuring  y^th  by  gi^th  of  an  inch.  Each  was  encircled  by  five  or 
six  raised  ribs  running  parallel  to  each  other  longitudinally,  somewhat  like 
the  varices  of  a  wentle-trap :  viewed  perpendicularly  to  the  ribs,  the  form 
is  symmetrical — a  long  narrow  oval.  The  whole  siu'face  between  the  ribs 
appeared  punctured  or  granulate,  and  the  colour  was  a  dull-brownish  yellow. 
Under  pressure  it  was  ruptured,  and  discharged  an  infinitj^  of  atoms,  of  an 
excessive  minuteness,  but  every  one  of  which  for  a  few  seconds  displayed 
spontaneous  motion.  Their  whole  appearance,  and  the  manner  in  which 
they  presently  turned  to  motionless  disks,  were  exactly  the  same  as  the 
spermatozoa  which  the  male  eggs  of  other  Rotifera  contain,  except  that 
these  were  so  minute." 

Mr.  Dalrymple  describes  similar  peculiar  ova  in  Notommata  (AsjjJancJma) 
to  consist  of  an  aggregation  of  cells  and  of  pigment-granules,  without  a  dis- 
tinguishable germinal  vesicle. 

The  most  complete  and  satisfactory  account  of  the  structure  and  develop- 
ment of  the  winter  ova  is  supplied  by  Prof.  Huxley  in  his  Histoiy  of  Laci- 
nularia  (T.  M.  S.  1852,  vol.  i.);  we  wiU,  however,  preface  it  by  Leydig's 
description.  AYe  learn  from  this  writer  that  in  winter  ova,  a  space  filled 
with  fluid  usually  intervenes  between  the  yelk  at  each  pole  or  end  of  the 
egg,  and  the  inner  shell,  as  in  Tubicolaria,  and  that,  according  to  Weisse's 
observation  of  Bracliioniis  urceolaris,  the  outer  shell,  when  the  embiyo  is 
ready  to  come  forth,  springs  open  in  a  valvular  or  a  lid-like  manner.  The 
central  portion  of  the  yelk  has  a  darker  and  more  granular  appearance,  and 
is  surrounded  by  a  clearer  peripheral  or  cortical  lamina,  as  in  BracMonus 
Baheri,  Notommata  Myrmeleo,  and  N.  centrura.  Intermingled  \\ith  the  yelk- 
molecules  are  numerous  clear  vesicles,  and  oftentimes  fat-particles ;  moreover, 
the  yelk  oi  Notommata  Sieboldii  has  a  yellowish-red  coloiu'  (XXXVII.  27, 28). 
These  "  lasting  ova,"  as  Ehrenberg  has  otherwise  named  them,  are  always 
developed  externally  to  the  animal.  Like  the  summer  eggs,  they  are  fre- 
quently carried  about  by  the  parent ;  it  would  not  seem,  however,  that  they 
ever  accumulate  in  groups  about  the  cloaca,  but  that  mostly  the  eg^  is 
solitary,  and  that  two  or  three  are  of  rare  occurrence.  Thus  in  BracMonus 
Bakeri  and  in  AscomoriDha  never  more  than  one  is  present,  in  BracMonus 
rubens  a  couple  are  occasionally  noticed,  and  in  Notommata  Siebolclii  the 
highest  number  seen  was  three. 

Concerning  the  changes  ensuing  on  development,  Leydig  states  that,  "  on 
the  formation  of  a  membrane  around  the  commencing  ovum  in  the  ovary, 
the  peripheral  portion  of  the  yelk  exhibits  numerous  clear  spots,  which  recall 
the  appearance  of  the  small  cells  originating  from  repeated  fission  of  the 
yelk  of  the  summer  ova.    From  tliis  we  may  conclude,  either  that  the  germi- 


OF  THE  ROTATORIA.  451 

iial  vesicle  may,  by  repeated  fission,  resolve  itself  into  numerous  clear  vesicles, 
without  any  further  change,  except  that  of  an  attendant  grouping  of  the  yelk- 
particles  about  the  products  from  the  germinal  vesicle,  or  that  perhaps  the 
winter  eggs,  at  theii'  origin  in  the  ovary,  enclose  a  number  of  nuclei  (germinal 
vesicles)  unlike  other  ova,  which  never  commence  with  more  than  one  nucleus 
(germinal  vesicle).  If,"  continues  Leydig,  "  I  rightly  understand  Huxley, 
this  is  the  manner  of  development  of  the  winter  eggs  of  Lacinularia  socialis  ; 
and  the  bisection  into  two  equal  halves,  which  I  formerly  referred  to  fission, 
has,  according  to  this  writer,  no  relation  to  it." 

Respecting  this  description.  Prof.  Huxley  remarks  that  he  thinks  Leydig 
"  has  not  observed  the  genesis  of  the  ephippial  ova  with  sufficient  care,  and 
he  thence  interprets  theii'  stnictui'e  by  supposing  that  they  are  ordinarily 
fecundated  ova,  which  have  undergone  a  peculiar  method  of  cleavage  ;"  and 
having  quoted  the  opinion  of  other  naturalists,  he  goes  on  to  say — "  it  will  be 
observed  that  all  these  authors  consider  the  ranter  or  ephippial  ova  and  the 
ordinary  ova  to  be  essentially  identical,  only  that  the  former  have  an  outer 
case.  The  tmth  is,  that  they  are  essentially  different  stnictiu'es.  The  true 
ova  are  single  cells  which  have  undergone  a  special  development ;  the  ephip- 
pial ova  are  aggregations  of  cells  (in  fact,  larger  or  smaller  portions — some- 
times the  whole  of  the  ovary)  which  become  enveloped  in  a  shell  and  simulate 
true  ova. 

"  In  a  fully-groTVTi  Lacinularia  which  has  produced  ova,  the  ovary  or  a 
large  portion  of  it  begins  to  assume  a  blackish  tint  (XXXYII.  22) :  the  cells, 
with  theii'  nuclei,  undergo  no  change ;  but  a  deposit  of  strongly- refracting 
elementary  granules  takes  place  in  the  pale  connecting  substance.  Every 
transition  may  be  traced,  from  deep-black  portions  to  unaltel'ed  spots  of  the 
ovarium ;  and  pressure  always  renders  the  cells,  with  their  nuclei,  visible 
among  the  granules.  The  investing  membrane  of  the  ovary  becomes  sepa- 
rated fi'om  the  dark  mass,  so  as  to  leave  a  space  (XXXYII.  24) ;  and  the 
outer  sui'face  of  the  mass  invests  itself  with  a  thick  reddish  membrane,  which 
is  tough,  elastic,  and  reticulated  from  the  presence  of  many  minute  apertures. 
This  membrane  is  soluble  in  both  hot  nitric  acid  and  caustic  potassa. 

"  The  nuclei  and  cells,  or  rather  the  clear  spaces  indicating  them,  are  still 
visible  upon  pressure,  and  may  be  readily  seen  by  bursting  the  outer  coat. 

"  By  degrees  the  ephippial  ovum  becomes  lighter,  until  at  last  its  colour  is 
reddish -brown,  like  that  of  the  ordinary  ova ;  but  its  contents  are  now  seen  to 
be  divided  into  two  masses,  hemispherical  from  mutual  contact  (XXXVII. 
21).  If  this  body  be  now  crushed,  it  will  be  found  that  an  inner,  structure- 
less membrane  exists  within  the  fenestrated  membrane,  and  sends  a  partition 
inwards,  at  the  line  of  demarcation  of  the  two  masses.  The  contents  are 
precisely  the  same  as  before,  viz.  nuclei  and  elementary  granules.  This, 
indeed,  may  be  seen  thi^ough  the  shell  without  crushing  the  case. 

"  I  was  unable  to  trace  the  development  of  these  ephippial  ova  any  further. 
Those  of  Notoynmata,  it  appears,  lasted  for  some  months  without  change  (Dal- 
rymple). 

"  It  is  remarkable  that  in  Lacinularia  these  bodies  eventually,  like  the 
ephippium  of  Daphnia,  contain  two  o^nim-like  masses  ;  and  there  can,  I  think, 
be  Uttle  doubt  that  the  former,  like  the  latter,  are  subservient  to  reproduction. 

"There  are  two  kinds  of  reproductive  bodies  in  Lacinularia  : — 1.  Bodies 
which  resemble  true  ova  in  their  origin  and  subsequent  development,  and 
which  possess  only  a  single  vitellary  membrane.  2.  Bodies  half  as  large  again 
as  the  foregoing,  which  resemble  the  ephippium  of  Daphnia,  like  it  having 
altogether  three  investments,  and  which  do  not  resemble  true  ova,  either  in 
theu'  origin  or  subsequent  development ;  which,  therefore,-  probablv  do  not 

2g  2^ 


452  GENERAL  HISTORY  OF  THE  INFUSORIA. 

require  fecundation,  and  are  thence  to  be  considered  as  a  mode  of  asexual 
reproduction." 

The  multicellular  character  of  the  contents  of  these  ^  ephippial '  ova,  Cohn 
is  unable  to  confii'm.  In  his  very  valuable  essay  on  the  '*  Development  of 
Rotatoria  "  (Zeitschr.  1855),  this  able  observer  has  promulgated  the  hj^jothesis 
of  the  occurrence  of  the  phenomenon  of  "  alternation  of  generations,"  of  par- 
thenogenesis or  virgin- development.  A  resume  of  the  reasons  for  this  view 
may  stand  thus : — Female  Rotifera  lay  eggs  of  only  one  sex  ;  and  winter  eggs 
are  produced  only  by  certain  females  and  at  certain  periods — contemporane- 
ously, that  is,  Avith  the  generation  of  males  :  again,  the  males  are  too  few  to 
impregnate  the  whole  of  the  apparent  female  beings,  which  are  so  largely 
found,  and  always  replete  with  ova  in  course  of  development,  at  all  seasons. 
The  conclusion,  therefore,  forces  itself  upon  us  that  the  common  ''summer" 
ova  are  produced  Avithin  the  parent  animal  without  any  antecedent  genera- 
tive act  or  impregnation  ;  that  is,  in  other  words,  they  are  asexual  products  or 
germs.  If  this  be  tiTie,  it  follows  that  the  beings  producing  them  are  not 
true  females,  but  merely  asexual  nurses  (Ammen),  fiu'nished  Tsath  a  germinal 
mass,  but  destitute  of  a  real  ovaiy,  and  not  demanding  the  action  of  the  male 
for  the  development  of  its  germinal  elements.  On  the  other  hand,  the 
"  winter  "  must  be  considered  the  tnie  ova,  and  the  beings  producing  them 
the  only  true  females,  furnished  with  an  ovary,  to  which  the  energy  of 
the  speiTnatozoa  of  the  male  is  necessary.  But,  notA\athstanding  these  phy- 
siological differences,  the  mere  niu'ses  and  the  actual  female  Rotifera  are  in- 
distinguishable in  stinicture.  In  illustration  of  this  hypothesis,  its  analogy 
with  what  occurs  in  Aphis,  Daphnia,  and  Artemia,  may  be  quoted. 

Of  the  rate  of  development  of  these  winter  eggs,  we  know  little.  Huxley's 
account  would  render  it  a  final  act,  involving  the  sacrifice  of  a  large,  or  even 
of  the  largest,  part  of  the  ovary,  and  consequently  one  which  we  cannot  sup- 
pose capable  of  frequent  repetition.  Leychg  has,  indeed,  an  observation  which, 
if  accurate,  proves  a  rapid  reproduction  of  such  ova  by  the  ovary.  He 
informs  us  he  observed  an  isolated  individual  of  Notommata  Myrmeleo  lay 
the  solitary  bristle-shelled  winter  o\^im  which  its  oviduct  contained  about 
12  o'clock  in  the  day ;  and  on  rencAATiig  his  researches  at  3  in  the  afternoon, 
discovered  another  such  egg  completely  formed  in  the  ovaiy. 

This  author  recounts  also,  in  his  histoiy  oi  Notommata  Sieboldii,  the  following 
particulars,  which,  if  confinned,  would  prove  the  formation,  whether  of  winter 
or  of  summer  ova,  to  be  determinable  by  accidental  external  cii'cumstances : 
— "  When  I  kept  the  Notommata  for  some  days  in  clear  water  containing  no 
nutriment,  the  ovary  shrivelled,  the  granular  mass  (yelk)  altogether  vanished, 
the  germinal  vesicles  became  simple  bodies,  and  all  such  individuals  produced 
only  winter  eggs." 

That  the  Rotatoria,  on  the  approach  of  winter,  are  Likely  to  be  placed  under 
conditions  in  which  food  is  scarce,  and  which  are  unfavourable  to  vigorous 
life,  is  at  once  admissible,  and,  if  Ley  dig's  observation  be  correct,  furnishes 
an  explanation  of  the  generally  apparent  limitation  of  the  production  of 
winter  ova  to  that  season.  Be  this  as  it  may,  the  -winter  ova  must  be  re- 
garded as  indicating  the  conservative  tendency  of  natiu-e  in  providing  for  the 
continuance  of  the  species  by  organisms  so  constmcted  as  to  endui^e  the 
severity  of  the  winter  season,  and  to  retain  a  dormant  vitality  through  it, 
imtil  the  genial  influence  of  spring  awakens  them  into  activity  and  hfe. 

Fecundity  of  Rotatoria. — Although  the  Rotatoria  are  not  endowed  with 
the  various  faculties  of  reproduction  possessed  by  the  Protozoa,  yet  their  vast 
increase  by  eggs  only  is  astonishing.  Ehi'enberg  wrote  that  he  insulated 
a   single  specimen  of  HyrJatina  senta,  and  kept  it  in  a  separate  vessel  for 


OF  THE  KOTATORIA.  453 

eighteen  days,  that  duiing  this  interval  it  laid  four  eggs  per  day,  and  that 
the  young  of  these,  at  two  days  old,  lay  a  like  number.  From  these  data  he 
made  an  erroneous  calculation,  that  one  million  individuals  may  be  obtained 
from  one  specimen  in  ten  days,  that  on  the  eleventh  day  this  brood  would 
amoimt  to  four  millions,  and  on  the  twelfth  day  to  sixteen  millions. 

This  is  the  only  direct  observation  we  have  met  with  intended  to  prove 
the  remarkable  fertility  of  the  class,  yet,  throughout  the  history  of  the 
Rotifera  now  detailed,  numerous  incidental  illustrations  of  the  fact  occur, — 
for  example,  the  presence  of  several  ova  in  different  parts  of  the  sexunl 
apparatus,  in  various  stages  of  development,  and  the  observed  rapidity  of  the 
phases  of  development,  at  least  of  summer  ova. 

The  latter  continue  to  be  formed  and  deposited  throughout  the  whole  of 
the  waim  part  of  the  year ;  and  when  this  di-aws  to  its  close,  the  production 
of  the  winter  ova  provides  for  the  continuous  propagation  of  the  species. 

Ehrenberg,  in  his  specific  descriptions,  notes  the  number  of  ova  he  met 
with  at  the  time  of  obseiwation,  intimating  that  some  animals  bring  forward 
but  one  egg  at  a  time,  others  two  or  several. 

There  is,  very  probably,  a  difference  in  the  productiveness  of  various  species  ; 
but  differences  in  this  respect  will  also  occur  from  accidental  and  external 
circumstances,  such  as  abundance  of  food,  and  changes  of  temperatiu'e. 

MALE  EOTATORIA  AJND  MALE  EEPRODUCTIVE  OEGANS.       QTJESTIOX  OP  MALE 
AjS^D  FEMALE  ORGANS  EST  THE  SAME  INDIVIDUALS. 

Male  Rotatoria. — Few  male  Rotatoria  have  as  yet  been  determined.  Those 
decisively  made  out  are  those  of  Asplanchna  Brightwellii  {Notommata  anglica, 
Dalrymple),  AsjjlancJina priodonta  and  A.  Boivesii  (Gosse),  and  the  Notommata 
Sieboldii  (Leydig).  This  able  German  observer  argues  also  that  Enteroplea 
Hydatlna  is  the  male  of  Hydatina  senta,  Notoynmata  granularis  that  of  N. 
Brachionus,  and  Diglena  granidaris  that  of  Diglena  catellina.  Since  this  was 
written,  Colm  has  pursued  the  inquiry,  and  confirmed  Leydig's  conjecture, 
that  Enteroplea  Hydatina  (Ehr.)  is  the  male  of  Hydatina  senta.  He  has 
moreover  discovered  the  males  of  two  other  species,  \dz.  of  Brachionus  urceo- 
laris  and  Br.  militaris.  Still  more  recently,  Leydig  has  been  able  to  confirm 
his  belief  of  Enteroplea  Hydatina  being  the  male  of  Hydatina  senta  (Midler's 
Archiv,  1857,  p.  404)  ;  and  Cohn  has  discovered  the  males  otEuchlanis  dilatata 
and  Notommata  Parasitiis  (ZeitseJir.  1858,  p.  284).  Meanwhile  Mr.  Gosse 
had  discovered  the  male  animals  and  their  eggs  in  the  undermentioned  genera 
and  species  : — Brachionus  Pala,  B.  ruhens,  B.  ampliiceros,  B.  Bakeri,  B.  angu- 
laris,  B.  Dorcas,  B.  Midleri,  Sacculus  viridis,  Polyarthra  platyptera,  Synchctta 
tremida  (?),  and  in  all  probability  MeJicerta  ringens,  besides  the  three  species 
of  Asplanchna  pre^iously  detemiined  (Phil.  Trans.  1856). 

The  first  male  discovered  was  that  of  Asplanchna  Brightivellii,  then  sup- 
posed to  be  a  species  of  Notommata,  and  is  thus  described  by  Mr.  Brightwell 
(A.  N.  H.  1848,  ii.  p.  155) : — It  is  "  about  half  the  size  of  the  female,  and 
differs  from  it  in  form,  being  much  shorter  and  of  a  rude  triangular  shape. 
It  is  more  difficult  to  detect  than  the  female,  being  exceedingly  transparent, 
and,  from  the  emptiness  of  the  body,  appearing  little  more  than  a  transparent 
ciliated  bubble.  It  is  very  active,  and  occasionally  puffs  out  the  sides  of  its 
body,  so  as  entii'ely  to  alter  its  form,  and  remains  thus  distended  some  time.'^ 
There  was  no  indication  of  any  digestive  apparatus,  or  of  matters  in  course 
of  digestion. 

'^  At  the  bottom  of  the  body,  on  one  side,  is  a  conspicuous  round  sperm - 
vessel  or  testis,  in  which,  under  a  high  power,  spermatozoa  in  active  vibra- 
tile  motion  may  be  seen,  and  at  its  external  side  a  duct,  closed  by  distinct 


454  GENERAL  HISTORY  OE  THE  INFUSORIA. 

lateral  muscles.  Connected  with  the  testis  is  a  well-defined  intromittent 
organ,  and  a  conspicuous  passage  or  opening  for  its  extension  from  the  body 
of  the  animal.  In  the  opposite  lower  angle  are  three  small,  irregularly- 
foi-med,  kidney- shaped  bodies,  connected  with  an  angular  lobe  or  muscle 
lying  beneath  them.  The  male  is  also  furnished  with  the  delicate  mem- 
branous plicated  bag,  and  rudiments  of  the  curled  tubular  structure,  found 
in  the  female." 

Besides  determining  the  dioecious  character  of  this  Rotifer,  Mr.  Brightwell 
was  also  enabled  to  repeatedly  verify  the  occurrence  of  an  actual  coitus  occur- 
ring between  the  sexes,  and  enduring  the  greater  part  of  a  minute. 

The  male  of  the  allied  species  Asplanclina  priodonta  was  described  by  Mr. 
Gosse.  As  the  description  supplies  additional  particulars  concerning  the 
organization,  we  extract  it  entu^e. 

Having  isolated  an  adult  female,  in  which  the  developing  yoimg  seemed 
different  from  the  ordinaiy  embiyos,  he  at  length  had  the  satisfaction  of 
seeing  two  males  born.  ''  Another  was  produced  the  same  evening  from 
another  parent,  likewise  under  my  eye." 

"  The  length  of  these  specimens  (XXXVI.  7,  8)  (male)  was  yy^th  of  an 
inch  (that  of  the  females  was  -^t^  to  y^^d  of  an  inch).  They  had  a  general 
agreement  in  outline  with  the  female.  But  the  outlet  corresponding  to  the 
vagina  was  at  the  veiy  bottom  of  the  ventral  side  (XXXVI.  7,  8  h),  which 
ran  down  to  a  point,  while  the  dorsal  side  was  rounded  off.  At  the  base  of 
this  tube  was  a  globular  sperm-sac,  with  a  short  thick  penis  in  front,  the 
whole  nearly  surrounded  by  a  delicate  glandular  mass.  The  place  of  the 
stomach  was  occupied  by  a  long  sac,  having  a  slender  neck  originating  from  the 
fore  part  of  the  head  mass,  and  at  the  bottom  broadly  attached  to  the  sperm-bag. 
This  whole  organ  was  filled  with  minute  granular  matter,  except  three  or  four 
clear  globular  bladders ;  the  sperm-bag  showed  a  structure  very  similar. 

"  The  principal  muscles  agreed  with  those  of  the  female.  The  tortuous 
threads,  and  their  plexuses,  were  represented  by  two  thickened  glandular 
bodies,  extending  from  the  head  mass  to  the  foliaceous  substance  siuTounding 
the  sperm  bag ....  The  three  eyes  were  present,  situated  as  in  the  female, 
but  no  trace  of  jaws  was  discernible,  even  on  pressure,  nor  any  crop,  nor 
true  stomach.  These  animals  were  very  active,  swimming  rapidly  about,  and 
scarcely  still  an  instant.  On  one  or  two  occasions,  I  observed  one  of  the 
males  with  a  slender  process  protruded  to  a  considerable  length  from  the 
sexual  orifice,  and  adhering  to  the  glass  by  its  tip,  moving  round  on  it  as  on 
a  pivot." 

Leydig  admits  the  bisexual  or  dioecious  nature  of  the  Rotatoria  as  a  general 
fact ;  and  although,  he  says,  his  studies  have  been  diverted  from  special  re- 
searches on  this  matter,  yet,  from  the  descriptions  and  representations  of 
others,  he  believes  he  can  detect  several  male  forms  arranged  in  the  class  as 
distinct  species. 

Of  the  male  of  a  new  species,  which  he  calls  Notommata  Sieholdii,  but 
which  is  equally  a  member  of  the  genus  As^lcmchna  with  "  the  supposed  new 
Notommata  "  of  BrightweU,  he  has  given  an  elaborate  description  and  draw- 
ings. He  remarks  that  in  all  details  of  organization  it  agrees  with  Mr. 
Dalrymple's  account,  but,  unlike  the  English  species,  differs  considerably  in 
figure  from  the  female,  especially  by  the  presence  of  four  pointed  arms 
(XXXVII.  29).  He  remarks  that  ''  the  so-called  "  sperm-hag  of  Dalrymple 
is  the  testicle,  and  what  that  author  terms  the  "  penis  "  is  its  duct.  The 
figures  he  gives  of  the  seminal  corpuscles  are  not  altogether  distinct,  although 
the  resemblance  between  them  and  those  of  Notommata  Sicholdii  are  unmis- 
takeable.     However,  I  must  point  out  an  error  into  which  Dalrymple  has 


OF  TUE  ROTATOEIA.  455 

fallen,  in  describing  the  linear  seminal  corpuscles  that  lie  parallel  to  one 
another  about  the  outlet  of  the  seminal  vesicle  to  be  bundles  of  muscular 
fibres  attached  to  the  base  of  the  penis,  and  acting  as  ^*  ejacidatores  seminis.'' 

The  Enterojolea  Hydatina  (Ehr.)  is,  in  Leydig's  opinion,  the  male  of  Hydatina 
senta  :  the  reasons  for  this  belief  briefly  are,  that,  according  to  Ehrenberg's  de- 
scription and  figures,  the  Enteroj^lea  has  neither  jaws  nor  teeth  ;  that  its 
ovary  is  homogeneous  and  granular ;  that  the  animal  is  always  smaller  than 
Hydatina  senta ;  and  that  among  the  eggs  of  this  last-named  species,  those 
developing  into  embryo  Enteroplea  were  intermixed.  Now  each  and  all  these 
differential,  and  some  of  them  very  exceptional  characters,  are  at  once  inter- 
preted by  assuming  Enteroplea  to  be  a  male  animal.  Indeed,  in  no  female 
perfect  Eotifer  are  the  jaws  wanting,  and  even  in  very  young  specimens  the 
ovary  is  not  homogeneous,  but  contains  many  germinal  vesicles  or  spaces.  A 
reference  to  Dujardin's  description  and  engravings  adds  additional  weight  to 
this  opinion.  This  supposition  has  been  confirmed,  both  by  Leydig  himself 
Midler's  Archiv,  1857,  p.  404,  and  A.  JSf.  H.  1857),  and  by  Cohn  (Zeitschr. 
1855,  p.  451),  and  we  would  refer  the  reader  to  their  memoirs  for  an  ex- 
tended description  of  this  male  being.  By  these  researches,  the  testicle  and 
its  contained  spermatozoa,  together  with  a  male  projectile  organ,  the  absence 
of  a  digestive  apparatus,  and  other  sexual  peculiarities,  have  been  satisfactorily 
made  out. 

In  the  case  of  Notoimnata  granularis,  the  arguments  for  its  male  character 
are,  the  absence  of  the  maxillae,  and  probably  of  the  ovary  also — for  neither 
Ehrenberg  nor  Weisse  could  satisfactorily  make  out  the  existence  of  the  latter, 
— and,  further,  the  presence,  as  the  Berlin  Professor  points  out,  of  two  sorts  of 
eggs  upon  Notommata  Brachionus,  the  smaller  of  which  bring  forth  individuals 
of  the  supposed  different  species,  Notommata  granularis. 

The  evidence  for  the  male  nature  of  Diglena  granularis  (Weisse)  is  its 
constant  occiuTence  in  company  with  D.  CatelUna,  and  the  production  of 
two  sorts  of  eggs  by  the  latter,  the  smaller  of  which  give  birth  to  embryos 
wanting  the  dental  apparatus.  Such  imjierfect  beings  as  the  Diglena  granu- 
lans and  the  Notommata  granularis  were  explained  by  Weisse  to  be  immature 
or  premature  embryos.  "  It  is  truly  interesting,"  says  Leydig, ''  that  Weisse, 
at  the  time  he  wrote  perfectly  ignorant  of  male  Rotifera,  should  arrive  at  the 
conclusion  that  Notommata  granularis,  Diglena  gramdaris,  and  Enteroplea 
Hydatina  were  not  distinct  species,  but  the  incomplete  and  toothless  young 
of  the  several  species,  Notommata  Brachionus,  Digleyia  CatelUna,  and  Hydatina 
senta.''''  It  is  added  in  a  note — "  Under  the  name  Notommata  gramdaris  may 
weU  be  associated  together  the  veiy  similar  males  as  well  of  Notommata  By^a- 
chio7ius,  as  also  of  B.  ureeolaris  and  B.  Pala.''  A  few  notes  in  illustration 
may  be  added  from  Cohn's  account  of  the  male  of  Brachionus  ureeolaris 
(Zeitschr.  1855,  p.  471).  This  is  much  smaller  and  more  active  than  the 
females.  Its  rotary  apparatus  forms  a  wide  ciliated  rim  ;  but  its  cilia  are  not 
turned  inwards  and  downwards,  as  in  the  females,  to  enter  the  mouth,  for  no 
such  orifice  exists :  hence  there  is  no  maxillary  head,  no  intestine,  and  no 
gastric  glands.  In  the  place  of  those  organs  lies  a  large  pyriform  saccular 
testicle,  as  much  as  y  Ytnjth  of  an  inch  in  length,  incompletely  filled  with  fine 
dark  corpuscles,  which,  when  mature,  acquire  the  characteristic  figure  and 
swarming  movements  of  spermatozoa.  The  wall  of  the  testicle  is  excessively 
thick,  perhaps  muscular,  and  is  extended  upwards  mto  a  tliick  cylindiical  band, 
which  appears  to  serve  as  a  medium  of  attachment  to  fix  the  gland  above  to 
the  region  of  the  cephalic  disk.  At  its  posterior  end,  the  testis  presents  a  close 
longitudinal  striation,  and  is  perforated  by  an  aperture  which  opens  into  a 
wide  canal  ending  in  the  penis.     This  last-named  organ  has  the  aspect  of  a 


456  GENERAL  HISTOJir  OF  THE  INEUSORIA. 

short  tube,  which,  as  a  rule,  lies  free  upon  the  foot,  and  extends  nearly  to  its 
extremity.  Its  inner  canal,  and  its  external  border,  exhibit  vibratile  action. 
The  foot  is  transversely  wrinkled,  and  ends  in  two  small  toes.  About  the 
origin  of  the  penis  from  the  testicle  are  two  club-shaped  glands  which  pour 
their  secretion  into  the  canal ;  and  near  them  is  the  contractile  vesicle,  giving 
off  its  resj^iratory  canal  on  each  side,  with  the  usual  tag-like  appendages. 
Several  spherical  cell-looking  bodies  occur  about  the  head,  with  the  largest 
of  which  the  eye-specks  are  in  connexion,  and  w^hich  may  therefore  be  con- 
sidered the  cerebral  ganglion.  Upon  the  testis,  near  its  lower  end,  two  or 
three  vesicles  are  placed,  filled  ^\^th  dark  granules,  resembling  those  seen  in 
EnteroiDlea  Hydatina,  and  of  which  we  cannot  predicate  further  than  that 
they  are  not  of  the  natui^e  of  m^inary  concretions  (as  Leydig  imagined),  but 
in  some  way  belong  to  the  sexual  apparatus,  or  else  are  unconsumed  cells 
of  the  yelk-mass. 

The  tubular  or  band-like  prolongation  from  the  upper  extremity  of  the 
testicle,  noticed  by  Cohn,  and  considered  by  him  a  ''  suspensor  testis,"  repre- 
sents, in  Leydig's  opinion,  rather  the  nidiment  of  the  undeveloped  alimentary 
tube.  This  author  likewise  denies  Cohn's  statement  that  the  walls  of  the 
testis  are  thick  and  muscular,  asserting  that  they  consist  of  a  thin  membrane. 

The  spermatozoa,  i.  e.  the  fecundating  male  particles,  have  been  described 
by  Mr.  Dahymple,  Gosse,  and  Leydig.  We  borrow  the  description  of  the 
latter  as  the  more  recent : — "  The  testicle  (XXXYII.  29  c)  of  Notommata 
Sieboldii  is  at  once  seen  to  be  more  or  less  completely  filled  with  spermatozoa, 
arranged  about  the  excretory  duct  in  a  radiating  manner;  when  not  too  much 
compressed,  they  move  about  within  the  testis.  On  isolating  by  slight  pres- 
sure the  contents  of  the  organ,  may  be  noticed,  1,  large  round  vesicles,  in 
which,  by  a  stronger  magnifying  power,  two,  or  probably  more,  hyaline  nuclei 
with  nucleoli,  entii'ely  occupying  the  space,  may  be  distinguished  (XXXYII. 
30  e)  ;  2,  somewhat  larger  cell-formed  elements,  disposed  in  a  radiating 
manner  about  a  centre,  and  larger  towards  one  side  (XXXVII.  30  c) — at 
the  rounded  extremity  a  clear  nucleus,  with  a  nuclear  coi'puscle,  is  always 
placed ;  3,  elongated,  mostly  falcate  or  curved  structures,  which  have  the 
before -mentioned  nuclei  in  their  interior,  and  on  one  margin  are  expanded 
into  an  evidently  undulating  membrane  (XXXYII.  30  a,  b,  d).  They  move 
about,  and  swim  hither  and  thither,  in  such  a  manner  that  they  remind  one 
not  a  little  of  many  Infusoria,  having  a  clear  sharply- defined  contoiu-  and  a 
rod- like  figure,  mth  a  sHght  enlargement  at  the  middle.  It  is  these  bodies 
which  lie  around  the  commencement  of  the  excretory  duct,  and  give  rise  to 
the  apparent  striation  above  aUuded  to."  In  Hydatina  senta  the  spermatozoa 
are  likewise  of  two  forms,  and  are  noticed  sometimes  to  have  a  swarming 
movement  even  within  the  testis. 

Leydig  has  been  imable  to  satisfy  himself  whether  the  stave-  or  rod-like 
variety  (XXXYII.  30/)  is  to  be  considered  the  ripest  of  the  spermatozoa, 
and  derived  from  one  of  the  other  forms,  or  whether  there  are  two  sorts  of 
spermatozoa  in  Notommata  Sieboldii,  as  there  are  in  Paludina  vivijpara,  one 
of  the  MoUusca. 

Perty  states  briefly  and  generally,  of  the  spermatozoa  of  Eotatoria,  that  they 
have  a  broad-oval  refracting  body,  and  a  tail-like  appendage. 

The  spermatozoa  have  been  seen  within  the  abdominal  cavity  of  not  a  few 
female  Rotifera,  freely  moving  about  wdthin  it.  For  instance,  it  has  been 
witnessed  in  Braehio7ius,  Conocliilus,  Lacimdaria,  Megalotrocha,  and  Hyda- 
tina. It  is  not  known  how  they  reach  this  cavity,  since  the  cloaca  into 
which  they  are  normally  received  is  a  closed  sac.  Cohn  imagines  they  may 
enter  through  some  aperture  in  the  integument  as  yet  unnoticed  ;  it  is,  how- 


OF  THE  ROTATORIA.  457 

ever,  more  conceivable  that  thej  may  pass  from  the  cloaca  into  the  respiratory 
tubes,  and  escape  into  the  general  cavity  through  the  \dbratile  tags — supposing 
these  last  to  terminate  by  open  mouths.  On  the  other  hand,  it  is  just  possi- 
ble that  some  supposed  examples  of  the  presence  of  spermatozoa  within  the 
abdominal  cavity,  have  rather  been  instances  of  parasitic  beings  (Entozoa)  in 
the  interior.  Thus,  in  Hijdat'ina  senta,  Leydig  describes  the  interior  occupied 
by  many  numerous  active  animalcules,  which  he  refers  to  the  genus  Astasia. 

The  minute  male  beings  just  considered  are  brought  into  existence  for  the 
sole  purpose  of  feitilizing  the  ova  of  the  larger  and  highly- organized  female 
animals.  In  relation  to  the  females,  they  may  be  looked  upon  as  little  other 
than  parasites  ;  they  are  even  deficient  in  organs  necessary-  to  cany  on  their 
owTi  existence :  the  one  piu'pose  of  impregnating  the  opposite  sex  being 
fulfilled,  theii'  career  is  ended ;  and  this  career  is  so  brief,  that  the  complicated 
apparatus  otherwise  required  to  nourish  and  sustain  the  beings  can  be  dis- 
pensed with. 

The  early  history  of  the  male  Eotifer  is  that  of  the  female.  The  evolution 
of  the  ovum  from  the  ovary,  and  the  changes  transpiring  in  the  contents  of 
the  egg  untn  the  several  organs  become  distinguishable,  are  identical  in  the 
two.  The  following  particulars  from  Cohn's  paper  (Zeitschr.  1855,  p.  471) 
will  serve  for  illustration.  The  males  of  Bracliionus  iirceolaris  are  developed 
from  smaller  eggs  than  the  females,  and  which  are  adherent  in  large  number 
at  the  same  time  to  the  parent-animal.  These  eggs  are  very  spherical,  and 
reach  -g-J-jyth  of  an  inch  in  length  and  ^-J^th  in  diameter.  Their  shell  is  more 
delicate,  the  contents  clearer  and  much  more  transparent,  from  containing 
fewer  granules,  and  of  a  pale-yellow  hue,  whilst  the  usual  simimer  eggs  are 
dusky  grey.  Even  when  matm-e,  this  greater  transparency  and  absence  of  colour 
persist.  Fission  proceeds  in  the  same  way  as  in  the  female  ova  ;  and  after 
it  has  been  many  times  repeated,  the  different  organs  of  the  embryo  begin  to 
make  theii'  appearance, — the  red  eye-specks  being  among  the  fii^st.  However, 
unlike  what  happens  in  the  female  ova,  no  signs  of  the  maxillary  apparatus 
come  into  view,  but  two  or  three  dark  heaps  of  granules  which  are  not  seen 
in  those.  "When  mature,  the  embryo  springs  from  the  shell  through  a  trans- 
verse rupture,  and  is  then  seen  to  have  a  totally  different  figure  from  the 
female  beings,  and  at  least  three  times  smaller.  When  completely  extended, 
it  measm-es  only  between  -g^rth  and  2-^4^11  of  an  inch  in  length,  and  yi^th 
to  -gJ-oth  in  mdth,  and  is  observed  at  the  first  glance  to  be  destitute  of"  the 
firm  integument  or  shield  of  the  female  animals,  and  to  have  a  short- cylin- 
drical figure,  prolonged  anteriorly  in  the  form  of  a  short  head  separated  by 
a  constriction  from  the  body.  The  foot  is  short  and  tubular,  the  head  crowned 
by  a  flattened  disk  expanded  into  a  wide  margin,  which  is  clothed  with  long 
vibratile  cilia  and  a  few  non-^ibratile  bristles.  Their  movements  are  extra - 
ordinaiily  energetic. 

The  same  female  may  lay  in  succession  several  male  ova.  According  to 
Leydig,  both  male  and  female  ova  are  not  generated  at  the  same  time.  The 
small  size  and  relatively  incomplete  organization  of  the  male  Rotifera  is  a 
circumstance  not  peculiar  to  the  class ;  the  like  is  seen  in  the  imperfect 
"imago"  of  many  Insects,  destined  only  to  a  sexual  purpose,  in  the  para- 
site-like males  of  Lerncea,  in  the  miniature  and  incomplete  males  of  Daph- 
niadce,  and  in  the  equally  inferior  male  representatives  of  Polynoe,  E:cogone, 
and  of  the  j^ematoda  generally,  among  Vermes.  Leydig,  moreover,  finds  an 
analogous  fact  in  the  Siphonophora,  in  which  he  assumes  the  so-called  genital 
capsules,  distributed  everywhere  in  the  aggregate  mass  of  animals,  to  have  a 
male  character,  and  shows  this  opinion  is  in  harmony  with  the  views  put 
forward  by  Leuckart  respecting  them. 


458  GEIfEEAL  HISTORY  OF  THE  INFUSORIA. 

Mr.  Gosse's  conclusion  (Phil.  Trans.  1857,  p.  322)  is,  that  "  a  distinction 
of  sex  is  the  normal  condition  of  the  class,  or  at  least  of  that  group  which  is 
most  typical,  viz.  such  as  have  articulated  mallei  working  upon  a  separate 
articulated  incus.  Whether  the  same  rule  prevails  so  generally  in  those  which 
have  the  mallei  and  incus  fused  together  into  quadi^antic  masses,  and  in  those 
in  which  the  organs  exist  in  a  rudimentary  condition,  is  a  question  yet  to  be 
determined.  As  these  are  certainly  the  lowest  forms  of  their  class,  it  is  pos- 
sible that  hermaphroditism  may  be  foimd  in  them — in  the  Philodinadce,  for 
instance." 

The  summary  of  the  facts  as  yet  ascertained,  concerning  male  Rotatoria, 
will  form  a  valuable  addendum  to  our  account : — 

**  The  most  prominent  thing  that  stiikes  us  is  the  absolute  and  universal 
atrophy  (so  to  speak)  of  the  digestive  system  in  male  Rotifera.  Another 
curious  peculiarity  is  the  dissimilarity  that  always  exists  between  the  sexes. 
In  Asi^lanchna  and  Hydatina  the  resemblance  is  at  its  highest  point ;  in 
every  other  instance  observed,  the  sexes  are  so  imlike,  that  they  would  be 
taken  for  widely-remote  genera.  The  male  is  always  inferior  in  size,  and 
also  in  organization,  to  the  female. 

'^Whether  certain  individuals  produce  only  male,  and  others  only  female 
young,  or  whether  separate  impregnations  are  required  for  the  production  of 
the  separate  sexes,  I  do  not  know ;  but  from  all  my  observations  I  gather 
that  the  development  of  the  one  sex  never  takes  place  coetaneously  with  that 
of  the  other  ;  for  male  and  female  eggs  are  never  seen  attached  to  the  same 
parent,  and  the  immatui-e  eggs  in  the  ovary  invariably  develope  themselves 
into  the  same  sex  as  those  which  are  already  extruded. 

"  The  duration  of  life  in  the  male  is  always  very  brief.  I  have  never  been 
able  to  preserve  one  alive  for  twenty-four  hours.  Their  one  business  is  to 
impregnate  the  females,  which  is  the  work  of  a  few  minutes,  probably,  in  a 
state  of  freedom  ;  and  for  this  momentary  occupation  no  supply  of  loss,  by 
assimilation  of  food,  is  wanted  ;  and  hence  we  can  understand  the  lack  of  the 
nutritive  organism. 

"  Some  organs  are  found,  with  greater  or  less  distinctness,  in  all.  The 
(presumed)  male  of  Hydatina  senta  received  its  names  of  Enteroplea  and 
Organ-fisch  from  Ehrenberg  on  account  of  the  copiousness  of  its  internal 
organization.  A  muscular  system  is  well  developed  there,  and  in  the  males 
of  Asplanchna  and  of  Bracliionus  Midleri ;  and,  from  the  varied  movements 
of  all,  its  existence  may  be  inferi'ed  where  it  is  not  detected.  The  fi^ontal 
cilia  are,  in  almost  all  cases,  much  more  developed  than  in  the  females  ;  the 
result  of  which  endowment  is  seen  in  the  excessive  rapidity  with  which  the 
male  shoots  in  all  directions  through  the  water.  The  great  head-mass  of 
granular  substance  is  generally  distinct ;  and  in  several  cases  (as  in  the  ^5- 
jplancJince  and  in  Bracliionus  Dorcas  and  Br.  MiUlein)  the  great  occipital  gan- 
glion is  well-defined,  with  the  red  eye  seated  on  it  as  in  the  other  sex.  Even 
where  the  ganglion  is  not  apparent,  the  eye  is  conspicuous,  with  the  exception 
of  Sacculus  and  Polyarthra ;  and  in  this  last  instance  the  small  size  of  the 
animal  must  be  borne  in  mind,  and  the  density  of  the  anterior  parts. 

"  In  the  (presumed)  male  of  Hydatina,  in  those  of  all  the  Asplanchnce,  and 
of  Bracliionus  Dorcas,  there  are  organs  answering  to  the  lateral  convoluted 
threads  of  the  female ;  and,  in  Asplanclina  Briglitwellii  at  least,  these  are 
accompanied  by  tremulous  tags,  and  by  a  contractile  bladder. 

*•'  A  large  mass  of  substance  which,  being  perfectly  opaque,  appears  black 
by  transmitted  light,  but  is  white  when  the  rays  are  reflected,  is  so  generally 
found  in  male  Rotifera  as  to  be  characteristic,  though  it  is  not  universally 
present.     I  do  not  find  it  in  the  AspJanchncr,  nor  in  Sacculus.     On  the  other 


OF  THE  HOTATORIA.  459 

hand,  I  have  obseiTed  it  in  the  young  of  Stephmwceros,  Floscularia  compla- 
nata,  and  F.  cornuta  ;  and  Ehrenberg  mentions  it  in  F.  ornata  and  Ladnu- 
laria.  In  Stephanoceros,  it  was  certainly  associated  with  well-developed 
jaws ;  and  hence  I  presume  it  is  not  exclusively  an  indication  of  the  male 
sex.  The  mass  is  sometimes  broken  up  into  fragments,  of  irregular  size  and 
shape,  and  sometimes  apparently  pulverulent.  In  general,  it  appears  to  lie 
loosely  in  the  midst  of  the  granular  amorphous  matter  that  occupies  the  pos- 
terior region  of  the  body-cavity ;  but  in  Brachiomis  Pala,  and  especially  in 
Br.  amphiceros,  I  have  fancied  that  I  discerned  traces  of  a  vesicle,  within 
which  the  white  substance  seems  to  be  contained. 

"  On  the  nature  of  this  substance  I  have  no  light  from  personal  research. 
Dr.  Leydig,  however,  considers  it  to  be  a  urinary  concretion  (Harnconcre- 
mente),  analogous  to  the  chalky  fluid  which  is  d^charged  by  many  insects 
immediately  after  their  evolution  from  pupae. 

"  In  the  male  oiAsplanchna  BrightiueUn,  there  is,  as  its  discoverer  observes, 
^  a  conspicuous  round  sperm-vessel,  or  testis,  in  which ....  spermatozoa  in 
active  vibratile  motion  may  be  seen.'  Mr.  DaLrymple,  and  subsequently 
myself,  also  saw  these,  both  mthin  the  sac  and  discharged  by  pressure. 
Each  spermatozoon,  according  to  my  own  observation,  consists  of  an  oblong 
body,  yyi-^th  of  an  inch  long,  and  an  abnipt,  slender,  \4bratile  tail  of  equal 
length.  In  the  sperm-sac  of  A.  Sieholdii,  Dr.  Leydig  finds  various  seminal 
elements,  viz.  round  cells  ;  pyriform  cells,  drawn  out  to  a  fine  point,  and  ad- 
hering to  each  other  by  their  rounded  ends  in  a  stellate  manner ;  oblong 
bodies,  with  one  side  dilated  into  a  free,  undulating,  membranous  border ; 
and  slender,  stiff",  rod-like  bodies,  mth  a  central  swelling;  all  containing 
nucleated  nuclei.  On  the  male  of  A.  priodonta,  my  observations  were  too 
limited  to  determine  more  than  the  existence  of  the  globular  sperm-sac. 

"  In  Bmchionus  ruhens  and  Br.  MulJeri  I  found  spermatozoa,  which  I  have 
above  described.  In  the  latter,  the  sperm-bag  is  of  great  size,  and  contains, 
besides  the  spermatozoa  of  unusual  development,  slender  spiculifonn  bodies, 
which  may  be  the  equivalents  of  the  little  rods  described  by  Dr.  Leydig  in 
Aspl.  Sieholdii.  The  sperm-bag  (in  Br.  MuJJeri)  is  closed  posteriorly,  as  it 
is  also  in  Asj).  Briglitwellii,  by  what  appears  to  be  a  true  sphincter ;  and 
such  I  conjecture  to  be  the  explanation  of  those  diverging  lines  which 
M.  Dujardin  saw  in  Enteroplea  (so-called),  which  he  considered  to  be  pedi- 
cles of  his  '  touffes  de  granules,^  while  the  '  tonffes  '  themselves  I  take  to 
have  been  the  masses  of  uiinary  concrement.  Dr.  Leydig,  however,  con- 
siders the  whole  to  have  been  masses  of  spermatozoids. 

''  The  outlet  of  the  sperm-bag  is,  in  all  cases,  by  a  thick  protrusile  and 
retractile  penis.  Wherever  a  foot  exists,  this  intromittent  organ  is  continu- 
ously united  to  its  dorsal  side,  and  is  often  so  greatly  developed  that  the  foot 
itself  appears  as  an  appendage.  The  protrusion  of  the  organ,  at  least  in  most 
of  the  examples  that  I  have  noticed,  is  by  the  eversion  of  the  integuments. 
WTien  these  are  evolved  to  the  utmost,  the  organ  is  seen  to  be  a  thick 
column,  conical  or  nearly  cylindrical,  with  the  extremity  truncate,  and  sur- 
rounded^ by  a  wreath  of  \ibratile  cilia.  It  was  doubtless  the  extremity  of 
the  penis  that  M.  Dujardin  saw  as  '  un  organe  cilie  entre  Us  muscles  de  la 
queue,''  in  the  (so-caUed)  Eiiterop>lea.  The  male  of  Sacculus  viridis,  a  species 
which  is  footless  in  both  the  sexes,  is  the  only  example  in  which  I  have  not 
seen  the  penis  ;  but  the  organ  is  probably  wholly  retractile  within  the  body, 
and  my  observations,  on  the  only  indi\'idual  of  this  sex  that  I  saw,  were  in- 
sufficient to  determine  anything  concerning  it." 

That  male  Rotatoria  have  been  recognized  in  comparatively  few  species, 
admits  of  several  explanations.     The  smaller  size  and  comparative  rarity  of 


460  GENERAL  HISTOEY  OF  THE  INEUSORIA. 

the  males ;  their  dissimilarity  of  figure  to  that  of  the  females,  which,  coupled 
with  imperfect  examinations  or  misconception  of  their  interior  organization, 
would  readily  lead  to  their  institution  as  new  species  or  genera  ;  the  influ- 
ence of  the  j)revalent  hypothesis  of  a  hermaphrodite  nature,  and  the  conse- 
quent exclusive  search  for  male  organs  in  the  perfect  female  forms,  in  which, 
too,  the  uncertainty  appertaining  to  the  pui^^Dose  of  several  appreciable  tissues 
or  organs  would  tend  still  further  to  lead  astray  ;  the  short  existence  of  the 
males,  and  even  that  brief  life  limited,  it  would  seem,  to  a  particular  period 
of  the  year,  the  early  spring,  when  such  creatures  are  less  sought  after ; 
each  and  all  these  are  circumstances  which  have  caused  the  male  Rotatoria 
to  be  overlooked,  and  continue  to  do  so.  However,  the  non-recognition  of 
the  male  animals  occurs  not  only  in  the  case  of  the  Rotatoria,  but  also  of 
other  classes  of  animals,  even  more  higlily  organized  and  so  large  as  to  be 
capable  of  examination  without  the  aid  of  the  microscope.  Among  minuter 
organisms  in  which  an  uncertainty  prevails,  may  be  mentioned  the  Daph- 
niadce  and  other  Entomostraca,  among  the  majority  of  genera  of  which  the 
males  are  still  undetected,  nevertheless  the  bisexual  character  of  the  class 
is  admitted. 

The  comparative  rarity  of  male  Rotatoria  admits  of  an  interpretation  de- 
rived from  analogy.  It  is  a  well-recognized  fact,  that  in  several  classes  of 
Invertebrata  (for  example,  in  Daplmiadce  and,  among  Insecta,  in  the  genus 
Aphis)  several  generations  succeed  one  another  without  the  concurrence  of 
a  male  animal  in  their  production, — a  phenomenon  well  named  by  Prof. 
Owen,  Parthenogenesis  or  Virgin-generation.  Now  it  clearly  appears  that 
one  contact  with  a  male  Rotifer  may  suffice  for  the  fertiHzation  of  all  the 
germinal  cells  in  any  female  ovary,  and  be  folloAvcd  by  their  successive  de- 
velopment. To  use  the  language  of  Prof.  Owen,  the  spermatic  force  once 
applied  suffices  for  the  impregnation  of  a  multitude  of  ova,  or,  in  fact,  of  the 
whole  ovary ;  and  the  fact  quoted,  of  Aphides  developed  by  the  immediate 
action  of  the  spermatic  force  being  in  their  tiums  capable  of  reproducing 
others  by  gemmation  without  a  renewal  of  that  force,  warrants  the  supposi- 
tion that  an  analogous  phenomenon  may  exist  in  the  Rotatoria.  This  analogy 
is  strengthened  by  Mr.  Huxley's  interpretation  of  the  natm^e  and  piu'pose  of 
*'  winter  "  ova,  which  he  beheves  to  be  the  instniments  of  an  asexual  repro- 
duction. A  portion  of  the  ovary  seems  to  be  modified  and  extruded,  and  sub- 
sequently to  generate  a  couple  of  embrj^os.  On  the  other  hand,  in  the  Aphides 
an  internal  genninal  mass  remains  within  the  body,  and  a  portion  of  it  ap- 
pears to  be  abstracted  by  each  successive  individual  produced,  imtil  at  length 
the  spermatic  force  is  exhausted.  This  internal  germinal  or  reproductive  body, 
the  instrument  of  an  asexual  generation  in  the  Aphides,  is  then  surely  homo- 
logous with  the  extruded  external  generative  bodies,  or  ''ephippial  ova,"  of  Ro- 
tatoria. Such  an  asexual  reproduction  impHes  a  fewness  of  male  beings  com- 
pared with  the  multitude  of  young  which  must  be  developed  by  the  generative 
processes.  Again,  the  male  Rotatoria  are  not  only  developed  in  smaller  numbers 
than  the  female,  but  their  whole  term  of  existence  is  very  brief,  only  long 
enough  to  fulfil  their  generative  piu'pose  ;  and,  lastly,  they  are  to  be  found 
only  at  particular  seasons,  mostly  in  the  spring. 

Another  obvious  reason  for  the  scarcity  of  male  Rotifera  suggests  itself, 
viz.  that  the  social  institutions  of  the  class  may  not  be  on  the  monogamous 
model,  but  that  one  little  active  male  may  divide  his  favours  among  a  whole 
harem  of  females  before  he  completes  his  brief  career.  However  this  may 
be,  to  discover  the  male  of  any  one  species,  continuous  observation  is  needed, 
particularly  at  certain  times  of  the  year ;  and  it  must  be  confessed  that  but 
few  Rotatoria  have  hitherto  had  their  history  fully  investigated.     In  most 


OF  THE  ROTATORIA.  461 

cases,  the  examination  of  a  species  has  been  casually  undertaken ;  the  attention 
has  been  directed  to  it  only  by  some  accidental  cii'cumstances,  and  this  only  on 
some  one  occasion.  We  cannot,  therefore,wonder  that  the  rarely-occurring  males 
have  not  often  been  encountered.  But  the  most  satisfactory  means  of  deter- 
mining the  existence  and  characters  of  the  males  of  any  species  of  Eotatoria 
have  latterly  been  furnished  by  the  careful  descriptions  of  the  special  cha- 
racteristics of  male  ova,  whereby  they  can  be  distinguished  even  before  leaving 
the  oviduct,  and  their  develoi^mental  history  traced  forwards  until  their  ma- 
turity. 

AYe  may  mention  that  'Mi\  HaUett,  formerly  demonstrator  of  anatomy  in 
the  University  of  Edinburgh,  and  subsequently  a  student  in  anatomy  at  the 
College  of  Surgeons,  London,  directed  his  special  attention  for  many  years  to 
the  Eotatoria,  and  especially  to  the  detection  of  the  male  individuals  ;  and 
although  his  early  death  has  deprived  naturalists  of  the  published  results  of 
his  researches,  yet,  from  repeated  verbal  communication,  we  can  state  that 
he  had  arrived  at  the  discovery  of  the  male  beings  of  the  majority  of  the 
Eotatoria. 

Doubtful  Male  Organs. — Many  natui'alists  are  unprepared  to  admit  bi- 
sexuahty  to  be  the  universal  rule  in  Eotatoria ;  and  several  eminent  observers 
are  disposed  to  consider  certain  organs  in  female  animals  to  be  of  a  male 
sexual  character. 

Prof.  Williamson,  in  his  liistoiy  of  MeJicerta,  says — "  I  have  sought  in 
vain  for  any  organ  to  which  the  functions  of  a  spermatic  gland  can  be  indis- 
putably assigned.  Immediately  beneath  the  lower  stomach  and  the  conti- 
guous oviduct,  there  is  an  elongated  pyramidal  organ,  apparently  hollow,  the 
thick  extremity  of  which  is  directed  towards  the  ovary,  and  its  opposite  at- 
tenuated portion  passes  upwards  towards  the  cloaca,  between  the  oviduct  and 
the  general  integument.  Into  the  thick  inferior  extremity  of  this  organ, 
there  are  inserted,  exactly  opposite  to  each  other,  two  long-cylindiical  ap- 
pendages, which  diverge,  and,  passing  on  each  side  of  the  alimentary  canal, 
proceed  towards  the  upper  part  of  the  body,  where  their  extremities  are  not 
easily  traced.  In  but  one  instance  I  observed  them  to  terminate  in  a  series 
of  irregular  convolutions  near  the  base  of  the  two  tentacles.  Though  not  yet 
capable  of  demonstration,  it  appears  probable  that  this  curious  appendage 
may  be  a  filamentous  spermatic  tube  resembling  those  found  in  many  Arti- 
culata.  That  they  are  tubes,  and  not  muscular  bands,  appears  unquestionable  ; 
and  as  they  have  obviously  a  direct  connexion  with  the  cloaca,  they  might 
easily  discharge  a  fertilizing  secretion  into  that  common  excretory  canal,  from 
which  it  would  find  its  way  to  the  ovary  through  the  oviduct"  (p.  432). 

Now  it  is  to  be  remarked  that  Mr.  Williamson  states  he  could  discover 
"  no  special  organs  of  circulation  or  respiration,  no  vessels  or  pulsating 
organs,"  and  that  the  two  tubes  he  has  referred  to  as  being  possibly  sper- 
matic ducts  are  the  homologues  of  similar  ones  in  other  Eotifera,  to  which 
Ehrenberg  has  assigned  fertilizing  functions.  Further  on  he  observes — 
"  The  singular  bodies  resembling  spermatozoa  exist  in  various  parts  of  the 
organism,  where  they  are  apparently  enclosed  within  hollow  canals.  I  have 
never  seen  them  occupying  the  two  main  trunks  of  the  'water-vascular 
system  '  or  cseca ;  nor  can  I  succeed  in  tracing  any  connexion  between  them. 
In  several  cases  I  have  seen  one  or  two  of  these  curious  bodies  opposite  the 
centre  of  the  upper  stomach,  very  near  to,  but  independent  of,  the  main  csecal 
canal,  and  at  some  distance  below  the  point  where  the  latter  probably  sub- 
divides into  branches.  Near  the  neck  there  are  usually  from  two  to  three 
pairs.  Their  vibratilc  motion  ceases  the  moment  the  animal  is  killed  by 
pressure.  This  fact  does  not  countenance  the  idea  that  they  are  spermatozoa." 


462  GENERAL  HISTOKY  OF  THE  rNFTJSOSIA. 

From  the  above  remarks  and  statements,  it  seems  to  us  quite  clear  that 
the  pyramidal  sac  opening  into  the  cloaca,  and  its  upwardly-prolonged  canals 
referred  to,  are  nothing  more  than  the  *'  water-vascular  system  "  of  the  Me- 
licerta,  and  that  more  or  fewer  of  the  observed  vibratile  bodies  are,  in  fact, 
the  ciliated  tremulous  tags.  Had  the  pyramidal  sac  represented  a  testicle, 
spermatozoa  ought  to  have  been  seen  within  it ;  for  these  particles  are  readily 
cognizable  by  their  size,  figure,  and  movements. 

Prof.  Huxley  having  failed  to  find  a  male  among  some  scores  of  female 
Lacinularice,  or  a  single  ordinary  spennatozoon,  is  disposed  to  recognize  the 
male  sexual  element  in  some  singular  bodies  met  with  in  many  individuals  he 
examined.  These  bodies  '^  answered  precisely  to  Kolliker's  description  of 
the  spermatozoa  "  of  Megalotrocha.  They  had  a  pyramidal  head  about  y^-n-th 
of  an  inch  in  diameter,  by  wliich  they  were  attached  to  the  parietes  of  the 
body,  and  an  appendage  foiu^  times  as  long,  which  underwent  the  most  ex- 
traordinary contortions, — resembling,  however,  a  vibrating  membrane  much 
more  than  the  tail  of  a  spermatozoon,  as  the  undulating  motion  appeared  to 
take  place  on  only  one  side  of  the  appendage,  which  was  zigzagged,  while  the 
other  remained  smooth.  *' According  to  Kolliker,  again,  these  bodies  are 
found  only  in  those  animals  which  possess  ova  undergoing  the  process  of 
yelk- division,  while  I  found  them  as  frequently  in  those  young  forms  which 
had  not  yet  developed  ova,  but  only  possessed  an  ovary. 

"  Are  these  bodies  spermatozoa  ?  Against  this  view  we  have  the  unques- 
tionable separation  of  the  sexes  in  Notommata,  and  the  very  great  difference 
between  them  and  the  spermatozoa  of  Notommata.  Neither  the  mode  of  de- 
velopment, nor  the  changes  undergone  by  the  ovum,  afford  any  certain  test 
that  it  requires  or  has  suffered  fecundation,  inasmuch  as  the  process  closely 
resembles  the  original  development  of  the  Aphides. 

**  In  the  view  that  Kollil?;er's  bodies  are  true  spermatozoa,  it  might  be  said, 
1.  That  the  sexes  are  united  in  most  Distomata,  for  instance,  and  separated 
in  species  closely  allied  (e.  g.  D.  Ohenii).  2.  That  the  differences  between 
these  bodies  and  the  spermatozoa  of  Notommata,  is  not  greater  than  the  dif- 
ference between  those  of  Tritons  and  those  of  Rana.  3.  That  their  develop- 
ment from  nucleated  cells  within  the  body  of  MegaJotroclia  (according  to 
Kolliker)  is  strong  evidence  as  to  their  having  some  function  to  perform ; 
and  it  is  difficult  to  imagine  what  that  can  be  if  it  be  not  that  of  spermatozoa. 
However,  it  seems  to  me  impossible  to  come  to  any  definite  conclusion  upon 
the  subject  at  present." 

In  Melicerta,  Prof.  Huxley  notes  having  met  with  "  an  oval  sac  lying  below 
the  ovary,  and  containing  a  number  of  strongly-refracting  particles,  closely 
resembling  in  size  and  form  the  heads  of  the  spermatozoa  of  Lacinularia.^' 

These  views  of  Mr.  Huxley  are  of  no  value  in  deciding  the  question  ;  they 
rest  on  a  supposed  similarity  between  the  bodies  discovered  and  those  which 
Kolliker  behoved  to  be  spermatozoa  in  Megalatrocha, — an  opinion  not  incon- 
trovertible. On  the  other  hand,  their  spermatozoid  nature  is  discountenanced 
by  their  similarity  (which,  indeed,  Huxley  remarks)  to  undoubted  sperma- 
tozoa of  Rotifera. 

In  a  new  species  of  Melicerta  discovered  by  Prof.  Bailey  in  America,  that 
accurate  observer  found  that  pressure  between  two  plates  of  glass  hberated 
vast  numbers  of  spermatozoa ;  but  he  was  unable  to  ascertain  from  what 
organ  in  the  animal  they  were  set  free.  The  observation,  however,  is  im- 
portant as  indicating  the  existence  of  true  male  organs  in  Melicerta  of  a  Yeiy 
different  character  from  those  suggested  by  various  observers  as  having  pos- 
sibly fecundating  functions. 

Respecting  these  questionable  male  elements,  Leydig  has  the  following 


Oy  THE  EOTATORIA.  463 

remarks,  premising  that  the  detection  of  spermatic  particles  in  one  species 
furnishes  a  criterion  in  pronouncing  upon  the  signification  of  some  other 
bodies  : — "  I  have  heretofore  mentioned  my  idea  that  the  hairy  corpuscles  of 
Lacinulana  (occupying  the  general  cavity  of  the  body,  and  impelled  hither 
and  thither  by  its  movements)  are  seminal  particles :  although  this  is  still 
questionable,  yet  these  presumed  parasites  of  Lacinularia  must,  I  beHeve,  be 
still  rather  looked  upon  as  unequivocal  spermatozoids.  The  form  and  struc- 
tiire,  moreover,  of  the  bodies  figured  by  Huxley,  and  doubtfully  called  by 
him  spermatozoa,  have  an  evident  affinity  with  the  seminal  elements  of  No- 
iommata  Sieboldu.  It  also  seems  to  me  probable  that  the  spermatozoids 
portrayed  by  Kolliker  in  Megcdotrocha  are  really  such,  and  that  the  animals 
in  wMch  they  are  found  should  be  esteemed  as  previously  impregnated 
females.  I  moreover  consider  that  the  illustrations  furnished  by  Ehi-enberg 
of  Conochilus  volvox,  show  an  individual  with  two  spermatozoa;  and  the 
account  referring  to  it,  in  which  he  says  '  I  lately  saw  oscillating,  very  pe- 
culiar, gill-Kke  organs,  in  the  form  of  two  spirally-twisted  bands,  at  the  pos- 
terior extremity  of  the  body,'  also  speaks  in  favour  of  this  signification.  The 
entire  delineation  of  these  ^  spiral  gills  '  might  replace  very  well  that  of  the 
peculiar  seminal  elements  with  undulating  membranes." 

Afterwards,  when  speaking  of  the  parasites  of  Eotatoria,  Leydig  observes 
that  ha\ing  formerly  erroneously  described  the  seminal  corpuscles  of  Lacinu- 
laria as  parasites,  he  must  now,  on  the  other  hand,  class  the  once-presumed 
spermatic  particles  with  parasitic  organisms. 

In  the  course  of  subsequent  researches  on  Hydatina  senta  (Miiller's  ^rcZi^i;, 
1857,  p.  104),  Leydig  has  discovered  the  same  sort  of  structm^es  in  that  ani- 
mal. He  writes — "  They  are  globular  bodies  with  sharp  outlines  ;  and  their 
margin  looks  as  if  clothed  with  fine  haii^s.  Towards  the  end  of  March,  the 
entii-e  abdominal  cavity  was  in  many  specimens  so  filled  with  them  that  the 
animals  presented  a  white  appearance  by  reflected  light ;  yet  the  animals  so 
affected  swarm  about  just  as  briskly  as  the  others."  This  repletion  with  such 
particles  appears  to  us  to  intimate  that  they  cannot  be  spermatozoa,  either 
generated  within  the  beings  themselves  or  received  fi'om  without  from  male 
animals.  Indeed  their  oceuiTence  within  the  abdomen  of  Hydatina  senta 
is  of  itself  an  argument  against  their  being  spermatozoa  derived  from  a  male 
gland  within,  inasmuch  as  this  species  is  proved  to  be  impregnated  by  its 
own  male  partner,  formerly  known  as  the  Enteroplea  Hydatina,  The  ques- 
tion presents  itself,  whether  they  can  be  derivable  from  the  food,  as  products 
of  digestion  or  chyle-globules. 

The  search  for  male  Rotatoria  has  led  the  occasional  connexion  of  two  in- 
chviduals  to  be  noticed,  and  to  be  explained  as  of  a  sexual  character.  Periy 
noticed  two  individuals  of  Colurus  uncinatus,  and  two  of  Lepadella  ovalisy  in 
union.  But  such  connexions  may  rather  be  considered  accidental ;  for  Perty  re- 
marked a  Colurus  so  attached  to  LepadeUa,  and  a  Chmtonotus  Larus  to  Lepadella 
ovalis.  Cohn  has  had  his  attention  directed  to  the  same  cii'cumstance,  and 
remarks  that  two  Rotatoria  of  the  same  or  even  of  a  different  species  are 
very  often  to  be  seen  attached  together,  sometimes  by  the  back,  at  others  by 
the  abdomen,  at  others  by  the  pseudopodium,  and  to  swim  about  together  for 
a  length  of  time.  This  he  has  seen  in  Diglena,  Colurus,  and  LepadeUa  ;  it 
has,  however,  no  connexion  with  the  reproductive  function. 

Of  the  Duration^  and  Conditions  of  Life  of  the  Rotatoria,  and  of  theer 
Habitats  and  Distribution. — It  is  next  to  impossible  to  determine,  by  direct 
observation,  the  duration  of  life  among  the  Rotatoria  when  placed  under 
natural  and  favoui^able  conditions.  Many  may  well  be  supposed  to  survive 
from  their  birth  in  the  spring  until  the  winter,  and  not  a  few  even  through 


464  GENERAL  HISTORY  OF  THE  INEUSOEIA. 

this  season  until  some  future  period,  since  observations  prove  their  power  of 
assuming  a  torpid  condition  when  existing  circumstances  are  unfavourable 
to  the  full  exercise  of  life.  It  has  been  noticed  by  Ehrenberg,  of  some  Eota- 
toria  li\ing,  so  to  speak,  in  confinement,  or  in  a  limited  quantity  of  water 
under  examination,  that  when  the  weather  was  warm  and  nourishment 
abundant,  life  was  prolonged  to  18  or  20  days  and  more  ;  and  Mr.  Gosse  also 
speaks  of  a  MeUcerta  which  hved  in  confinement  for  14  days. 

The  conditions  of  life,  or  the  causes  affecting  the  vitahty  of  Rotifera 
favourably  or  unfavourably,  are  in  some  respects  very  remarkable,  as  an  ap- 
peal to  their  habitats  alone  would  abundantly  illustrate. 

It  is  during  the  height  of  summer  that  the  Rotifera  are  multiplied  most 
abundantly ;  but  when  the  cold  frosty  nights  of  autumn  supervene,  their 
numbers  undergo  a  rapid  reduction.  However,  often  during  the  most  beauti- 
ful parts  of  the  year,  as  Perty  remarks,  a  sudden  decrease  ^vill  occur. 

"  Two  kinds  of  disease,"  writes  Ehrenberg,  ''  destroy  the  Hijdatina  and 
most  of  the  Rotatoria :  1,  the  formation  of  vesicles,  which  give  rise  to  the 
appearance  of  small  rings  all  over  the  creature  ;  and,  2,  the  formation  of 
granules  which  so  penetrate  the  internal  organs  that  these  seem  composed  of 
them,  and  have  a  shagreen  appearance."  The  first  condition  has  been  noted 
by  Weisse,  who  regards  the  apparent  vesicles  as  parasitic  organisms. 

The  Rotatoria  also  suffer  from  the  overgrowth  upon  their  surface  of  Algae 
and  of  parasitic  animals,  Protozoa  and  the  like,  and  are  at  length  destroyed 
thereby.  Eoul  or  decomposing  water  is  incompatible  with  their  existence,  as 
are  some  chemical  mixtures,  whilst  to  others  they  seem  indifferent.  Thus 
Hydatince  have  been  fed  A^dth  rhubarb  and  indigo  in  powder  without  sensible 
effect,  and  neither  calomel  nor  corrosive  sublimate  Idlls  them ;  at  least,  they 
live  for  some  time  after  these  substances  have  been  mixed  with  the  water. 
Strychnia  causes  instant  death. 

The  deprival  or  the  want  of  renewal  of  aii'  in  water  inhabited  by  Rotifera 
causes  their  destruction,  for  example,  when  collected  in  abottle  for  examination, 
the  cork  being  allowed  to  remain  too  long.  In  like  manner  the  exclusion  of  air 
by  a  pellicle  of  oil  on  the  surface  of  the  water,  or  the  withdrawal  of  air  by 
means  of  an  au'  pump,  speedily  destroys  the  Rotatorial  inhabitants.  Ehren- 
berg affirms  that  they  exist  much  longer  in  an  atmosphere  of  nitrogen  than  in 
one  of  carbonic  acid  or  of  hydi'ogen,  and  that  the  vapour  of  sulphur  speedily 
puts  an  end  to  their  existence. 

Still  a  very  imperfect  renewal  of  air  seems,  at  least  in  some  instances,  to 
suffice — as  in  the  case  of  the  Rotifer  vulgaris  and  R.  parasita,  which  have 
been  seen  within  the  spheres  of  Volvox  and  in  the  cells  of  aquatic  plants 
(the  Vaucheria  clauata.)  Perty  likewise  mentions  the  Notommata  Werneclcii 
as  inhabiting  the  Vaucheria  ccesjpitosa  ;  and  Albertia  vermicularis  is  parasitic 
within  the  intestine  of  earth-worms  and  slugs.  In  all  these  instances  Hfe  is 
compatible  with  a  very  slight  renewal  of  atmospheric  air,  or,  iu  fact,  is  sup- 
ported amid  the  gases  generated  within  these  organic  beings  and  mixed  with 
their  fluids. 

The  evaporation  of  the  water  from  around  Rotifera,  as  when  under  exami- 
nation by  the  microscope,  is  a  frequent  cause  of  their  destruction,  by  the 
breaking  up  of  their  soft  parts.  But  there  is  a  happy  provision  against  such 
evil  consequences  ;  for,  so  soon  as  the  animal  experiences  the  deficiency  of 
water  around  it,  it  withdi'aws  its  tender  wheel  apparatus,  and  limits  its  ex- 
posed parts  as  much  as  possible,  by  retracting  its  pseudopodium  and  contract- 
ing itself  into  a  ball-like  form,  so  that  only  the  denser  integument  is  exposed 
to  the  injurious  influences,  and  the  evaporation  of  water  from  the  contained 
organs  reduced  to  its  minimum. 


OF  THE  EOTATOEIA.  465' 

Indeed  the  Kotatoria,  in  part  at  least,  have  a  remarkable  power  of  preserv- 
ing theii'  vitality,  not  only  when  left  dry  by  ordinary  evaporation,  but  also 
when  thoroughly  desiccated  by  the  assistance  of  heat.  Leuwenhoek  and 
Spallanzani  experimented  on  them,  and  announced  the  fact  of  their  revivifi- 
cation on  the  addition  of  moistm^e,  months  and  even  years  after  their  com- 
plete desiccation.  Schrank,  Bory  St.  Vincent,  and  Ehi-enberg  questioned  the 
tnith  of  this  statement,  at  least  in  its  full  acceptation  ;  and  the  Avriter  last- 
named  affirmed  "  that  wherever  these  creatures  are  completely  desiccated, 
life  can  never  again  be  restored.  In  this  respect  the  Rotifera  exactly 
coiTcspond  with  animals  of  a  larger  kind :  like  them,  for  a  time  they  may 
continue  in  a  lethargic  and  motionless  condition;  but,  as  is  well  known, 
there  will  be  going  on  within  them  a  consumption  or  wasting  away  of  the 
body,  equivalent  to  so  much  nourishment  from  without  as  would  be  needed 
for  the  sustentation  of  life."  ^N'either  the  last  statement  nor  those  preceding 
it  are  correct ;  MM.  Schultze  and  Doyere  have  repeated  and  confiiined  the 
experiments  of  the  old  observers  ;  and  the  latter  authority  concludes  that 
Eotifera  may  be  completely  diicd  in  pure  sand  in  the  open  aii%  and  in  a 
vacuum,  without  losing  the  capability  of  being  re\'ived  by  moistiu-e.  Many 
indeed  are  sacrificed  in  the  process ;  but  enough  recover  to  demonstrate  the 
possibihty  of  the  fact. 

This  extraordinaiy  power  of  resiLScitation  after  di^ying  explains  the  re- 
appearance of  Eotatoria  on  the  collection  of  water  in  shallow  pools  which 
have  been  entirely  dried  up  by  the  hot  sun  of  summer,  and  their  con- 
stant presence  in  the  diy  debris  of  the  roofs,  and  even  of  the  interiors  of 
houses. 

In  their  relation  to  temperature,  also,  the  Rotatoria  exhibit  great  tolerance. 
M.  Doyere  proved  that  when  placed  in  water  at  fi^om  113°  to  118°,  they 
could  afterwards  be  re\ived,  but  that  when  thrown  suddenly  into  boiling 
water  (at  212°)  they  were  at  once  killed.  In  the  latter  case,  the  sudden 
heating  is  supposed  to  coagulate  the  albuminoid  contents  of  the  animals,  and 
in  that  way  to  cause  death,  because  individuals  previously  dried  by  a  gradually 
raised  heat  of  216°,  252°,  and  even  of  261°,  were  many  of  them  still  capable 
of  being  revived. 

On  the  other  hand,  Rotatoria  can  live  in  water  at  the  freezing-point.  They 
are  to  be  found  under  ice,  and  also  within  the  hollow  ca^'ities  of  ice ;  and 
Perty  mentions  a  score  of  species  which  he  met  with  in  such  localities.  He 
also  recounts  meeting  with  individuals  contracted  in  a  more  or  less  globular 
figm-e,  preparatory,  as  he  sunnises,  to  a  winter  sleep  or  torpor.  He  figiu'es 
a  PhUodina  erytlirophthahna  (XXXYIII.  4)  in  this  condition,  which  is  pre- 
cisely the  same  as  that  assumed  when  the  animal  is  left  dry ;  and  he  adds 
that  when  Scaridium  longicaudum  assumes  this  state,  it  withdraws  its  head 
within  its  envelope  and  doubles  its  tail  under  the  abdomen,  just  in  the  same 
way  as  a  Podura.  Ehrenberg  doubtless  refers  to  this  same  contracted  con- 
dition in  the  account  before  quoted  from  him  (p.  449-50)  respecting  the 
Rotifera  found  at  great  altitudes  among  snow,  which  he  described  as  having 
an  ovate  figui'e  and  enclosed  in  an  egg-shaped  envelope. 

Conochilus  and  Lacimdaria  are  examples  of  Rotifera  living  in  aggregated 
masses.  The  former  recalls,  by  its  compoimd  revohing  spheres,  the  appear- 
ance of  Vohox  Glohator,  whilst  the  latter  occurs  in  small  transparent  jelly- 
like balls  adherent  to  the  leaves  of  aquatic  plants. 

At  times  the  Rotatoria  multiply  so  rapidly  in  smaU  stagnant  pools  as  to 
eoloiu^  the  water.  Hi/datina  senta,  Diylena  catellina,  Triartlira,  and  Lepa- 
della  are  adduced  by  Ehrenberg  as  producing  a  milky  turbidity  in  water,  and 
the  Typldlna  viridis  as  imparting  a  green  colour. 

2h 


466  GENERAL  HISTORY  OF  THE  INFUSORIA. 

The  Syncliceta  Baltica  has  been  presumed  to  be  phosphorescent;  and 
Anurcea  hiremis  was  discovered  in  phosphorescent  sea-water. 

The  Rotatoria  are  distributed  everywhere  over  the  surface  of  the  earth,  in- 
habiting its  waters,  both  fresh  and  salt.  Of  the  known  species,  by  far  the 
greater  number  are  dwellers  in  fresh  water,  abounding  in  pools,  ditches,  and 
gently-flowing  streams,  especially  where  aquatic  plants  grow  in  sufficient 
quantity  to  afford  shelter  and  indirectly  suj)ply  food  by  the  hosts  of  animal- 
cules which  congregate  on  and  about  them.  A  too  much  overgrown  or  shaded 
piece  of  water  is  less  favourable ;  for  they  require  a  complete  intermixture 
of  air  with  the  water,  and  the  vivifying  influence  of  the  sun,  for  their  healthy 
existence.  Some  species  especially  delight  in  the  little  turfy  pools  on  moors 
or  in  boggy  ground;  others  have  been  especially  found  in  green-coloured 
ponds — the  colour  being  due  to  Protozoa  and  minute  Algse,  which  furnish 
them  with  suitable  food. 

Some  of  the  early  observers  sought  these  animalcules  especially  in  infusions, 
very  generally  made  vrith  sage-leaves  and  chopped  hay ;  but  the  E,otifera  are 
comparatively  rare  in  infusions :  a  few  common  species  only  appear ;  and  unless 
the  infusion  be  comparatively  fresh,  none  will  be  found ;  for  they  occur  in  no 
fluid  in  which  decomposition  is  going  forward.  When  they  do  exist  in  these 
infusions,  they  appear  at  a  later  period  than  do  the  Monadina  and  less  highly 
organized  infusorial  forms. 

The  known  salt-water  species  are  comparatively  few ;  this  is  very  possibly 
owing  to  their  being  much  less  sought  after  than  the  freshwater  animals. 
The  principal  marine  forms  recognized  are  Brachionus  Millleri,  B.  he/ptatomus, 
and  Synchceta  Baltica.  Distemma  marina  and  Furcularia  marina,  Colurus 
uncinatus,  Q.  caudatus,  and  Aymrcea  striata  are  encountered  in  both  fresh  and 
salt  water  :  several  are  found  in  brackish  water. 

Immersion  in  water  is,  however,  not  necessary  to  their  existence :  thus  they 
are  to  be  found  in  the  damp  earthy  deposit  from  rain-water  spouts,  and  in  the 
detritus  of  the  walls  and  roofs  of  houses ;  in  the  moist  humus  or  decaying 
vegetable  matter  about  trees,  and  especially  upon  the  moist  roots  and  leaves 
of  mosses  and  lichens — for  example,  among  the  tufts  of  Brijum  and  of  Hyp- 
num,  from  which  they  may  be  separated  by  washing  with  a  little  water. 

We  have  mentioned  the  peculiar  habitat  of  Albertia,  within  the  intestine  of 
the  earth-worm,  of  which  animal  it  may  be  accounted  an  entozoon ;  the 
Notommata  Parasitus  also  leads  a  parasitic  existence  within  the  hollow  spheres 
of  VolvoM  GJohator;  and  M.  Morren,  many  years  since,  gave  the  following 
interesting  history  of  the  habitat  of  Botifer  vulgaris  in  the  cells  of  Vauclieria 
clavata  {A.  N.  H.  vi.  p.  344) : — 

"  The  labours  of  Keeper  show  that  the  cells  of  Sphagnum  are  sometimes 
furnished  with  openings,  which  place  their  interior  cavity  in  communication 
with  the  air  or  water  in  which  they  are  immersed.  This  skilful  observer 
satisfied  himself  that,  when  circumstances  are  favourable,  the  Rotifer  vulgaris, 
one  of  the  Infusoria  whose  organization  has  been  explained  by  the  researches 
of  Ehrenberg,  exists  in  the  cells  of  the  Sphagnum  obtusifoUum.  This  grew 
in  the  air,  in  the  middle  of  a  turf-pit :  but  RcBper  observed  its  leaves  in  water ; 
he  does  not  mention  whether  the  infusorial  animal  came  from  thence,  or 
whether  it  was  previously  contained  in  the  cavities  of  the  cells.  The  general 
purport  of  the  paper  seems  to  imply  that  these  Rotifers  exist  in  the  cells  of 
that  part  of  the  plant  which  was  exposed  to  the  air ;  and  in  this  case,  the 
presence  of  an  animal  so  complicated,  living  as  a  parasite  in  the  cells  of  a 
utricular  aerial  tissue,  is  a  phsenomenon  of  the  most  curious  kind  in  the  phy- 
siology of  plants,  and  the  more  so  as  this  animal  is  an  aquatic  one. 

"  I  recollected  that,  the  last  year  of  my  residence  in  Flanders,  I  found  at 


OF  THE  EOTATORIA.  467 

Everghem,  near  Ghent,  the  Vauclieria  clavata,  in  which  I  obseiTed  something 
similar.  M.  Unger  had  already  published  the  following  details  respecting 
this  plant  in  1828  :  '  Beneath  the  emptied  tubercles  and  at  several  points  of 
the  principal  stalk,  at  different  angles,  rather  narrower  branches  are  produced ; 
these  branches  are  generally  very  long,  and  greatly  exceed  the  principal  stalk 
in  length.  At  the  end  of  ten  or  twelve  days  after  their  development,  there 
are  seen,  towards  one  or  other  of  theii'  extremities,  here  and  there,  at  different 
distances  from  the  simimit,  j)rotuberances  of  a  clavate  form,  more  or  less 
regular,  straight  or  slightly  bent  back ;  and  others  on  the  sides  of  the  stalk, 
which  have  the  form  of  a  capsule  or  vesicle.  These  vesicles  are  at  first  of  a 
uniform  bright-green  colour ;  and  without  increase  of  size,  which  exceeds 
several  times  that  of  the  branches,  they  always  become  of  a  blacldsh-green 
colour,  darker  tow^ards  the  base  ;  and  then  one  or  two  globules  of  a  reddish- 
brown  may  be  clearly  distinguished  there,  often  suiTounded  by  smaller  gra- 
nules, evidently  destitute  of  motion,  whilst  the  great  ones  move  spontaneously 
and  slowly  here  and  there  in  the  interior  of  the  capsule,  by  unequal  contrac- 
tions and  dilatations,  whence  arise  remarkable  changes  of  form.  I  saw  these 
globules,  at  the  end  of  eight  or  ten  days  after  their  appearance,  still  enclosed 
in  the  capsule,  moving  more  and  more  slowly,  receiving  no  very  decided  in- 
crease, whilst  the  base  of  the  capsule  became  more  transparent ;  at  last  I 
observed  that,  instead  of  their  expulsion,  which  I  was  watching  for,  the 
extremity  of  the  capsule  at  the  end  of  some  days  took  an  angular  form,  and 
subsequently  gave  birth  to  two  expansions  in  the  form  of  horns  ;  it  remained 
in  this  state  and  became  more  and  more  pale,  whilst  the  animalcule  became 
darker  and  died ;  and  afterwards  it  ended  by  perishing  at  the  same  time  as 
the  other  parts  of  the  Conferva.' 

"Subsequent  researches  have  not  succeeded  in  informing  us  what  this 
animal  might  be,  of  which  Unger  spoke.  As  this  author  drew  so  much  atten- 
tion to  the  spontaneous  movements  of  the  propagula  of  the  Vauclierice,  and 
as  he  admitted  the  passage  from  vegetable  life — characterized,  according  to 
him,  by  immobility — to  animal  life,  the  principal  criterion  of  w^hich  was 
motion,  his  animalcule  was  confounded  with  the  propagula ;  and  no  one,  so 
far  as  I  know,  has  returned  to  this  very  interesting  subject. 

''  "VYhen,  therefore,  I  found  the  Vauclieiia  clavata  at  Everghem,  I  was  as 
much  surprised  as  pleased  to  see  the  mobile  body  noticed  by  Unger  better 
than  he  did.  With  the  aid  of  a  higher  magnifying  power,  I  found  it  easy  to 
ascertain  the  true  nature  of  the  animal ;  for  it  was  not  a  propagulum,  but 
a  real  animal,  the  Rotifer  vulgaris,  with  its  cilia  imitating  the  wheel,  its 
tail,  (fee. 

"  The  first  protuberances  or  vesicles  which  I  saw  containing  this  animal 
enclosed  but  one  of  them  ;  afterwards  they  laid  eggs  and  multiplied  ;  but  it 
seems  that  then  they  descend  the  tubes  of  the  Vaucheria  and  lodge  themselves 
in  new  protuberances,  whose  development  they  may  possibly  stimulate,  as  the 
gaUs  and  oak-apples,  or  organic  transformations  attributable  to  the  influence 
of  parasitic  beings. 

"  The  Rotifer  vulgaris  travels  quite  at  his  ease  in  these  protuberances  ;  he 
traverses  the  partitions,  displaces  the  chromule  and  pushes  it  to  the  two  ex- 
tremities of  the  vesicle,  so  that  this  appears  darker  at  these  parts.  One  day 
I  opened  a  protuberance  gently :  I  waited  to  see  the  Rotifer  spring  out  and 
enjoy  the  liberty  so  dear  to  all  creatiu-es,  even  to  infusorial  animals  ;  but  no 
— he  preferred  to  buiy  himself  in  his  prison,  descending  into  the  tubes  of  the 
plant,  and  to  nestle  himself  in  the  middle  of  a  mass  of  green  matter,  rather 
than  swim  about  freely  in  the  neighbourhood  of  his  dwelling. 

''  Some  of  these  protuberances  had  greenish  threads  appended  to  their  free 

2h2 


468  GENERAL  HISTORY  OF  THE  INFrSORIA. 

end,  and  others  had  none :  I  thought  at  first  that  these  threads  were  some 
mucus  from  within,  escaped  thi'ough  some  opening  which  might  have  served 
the  Rotifer  as  an  entrance  ;  but  an  attentive  and  lengthened  observation  con- 
vinced me  that  in  this  there  was  no  solution  of  continuity,  and  that  the  arrival 
of  the  Rotifers  in  the  Vaucherice  was  not  at  all  to  be  explained  in  this  way. 
How  are  these  parasitic  animalcules  generated  within  them  ?  This  is  what 
further  research  has  some  day  to  show.  Meanwhile  I  have  thought  that  it 
should  be  made  known  that  the  animalcule  foimd  in  the  Vauclierice  by  linger 
was  the  Rotifer  vulgaris  of  zoologists." 

Several  of  the  Philodincea,  and  particularly  the  CaUiclince,  have  been  met 
with  in  snow,  along  with  the  so-called  red  snow,  in  very  cold  regions,  and 
at  considerable  elevations,  such  as  above  the  pei'petual  snow-line  of  the 
Alps.  Perty  informs  us  that  mosses  and  lichens  collected  in  the  Swiss 
mountains,  at  a  height  of  9000  feet,  have  yielded,  on  wasliing  with  distilled 
water,  numerous  Infusoria,  including  several  Rotatoria,  ^4z.  CalUdina  ele- 
gans,  Rotifer  vulgaris,  Philodina  roseola,  DigJena  catellina,  and  Ratidus 
lunaris. 

We  have  no  data  whereon  to  construct  laws  of  geographical  distribution 
for  the  Rotatoria.  Obseiwation  has  proved  no  definite  regional  limitation  of 
species ;  wherever  searched  for,  the  same  species  seem  discoverable. 

Owing  to  the  perishable  natru'e  of  theii^  tissues,  the  Rotifera  do  not  occui- 
in  a  fossil  state  ;  they  are,  moreover,  rare  components  of  the  showers  of  In- 
fusorial dust. 

Of  the  Affinities  and  Classification  of  the  Rotatoria. — That  the 
Rotatoria,  by  their  high  degree  of  organization,  should  be  elevated  in  the 
animal  scale  far  above  Protozoa,  is  now  universally  admitted.  Indeed  they 
cannot  be  rightly  comprehended  among  Infusoria  if  this  term  be  accepted  to 
indicate  a  definite  class  of  beings ;  for  although  there  are  slight  general  re- 
semblances between  some  Rotatoria  and  Protozoa,  no  true  near  affinities  of 
structure  exist  between  them. 

A\Tiile  naturalists  generally  are  in  accord  on  this  necessaiy  separation  of 
Rotatoria  from  Protozoa,  they  are  much  at  variance  respecting  the  relative 
position  of  the  Rotatoria  in  a  classification  of  the  Invertebrata,  or,  in  other 
words,  concerning  the  true  affinities  of  the  class.  Thus  Burmeister,  Owen, 
Lej'dig,  Dana,  and  Gosse  would  range  them  among  Cinistacea  as  a  particular 
order;  whilst  Wiegmann,  Milne-Edwards,  Wagner,  Siebold,  Cohn,  Perty, 
Williamson,  Huxley,  and  others  would  class  them  with  Vermes — a  section 
comprehending  Helmmthae,  Tiu-bellaria,  and  Annelida. 

We  shall  first  state  the  argiunents  used  to  demonstrate  the  Crustacean 
alliance,  which  are  most  fully  and  powerfully  brought  forv\'ard  by  Leydig ; 
they  are,  that 

''  The  external  figure  is  rather  that  of  Crustacea  than  that  of  Yeinnes. 
None  of  the  latter  have  a  jointed  organ  of  motion,  such  as  most  Rotifera 
possess  in  their  annulated  or  jointed  pseudopodium  devoid  of  aU  viscera. 

'<  The  shield-like  hardened  integ-ument  or  lorica  of  some  species,  such  as 
Euchlanis  and  Salpina,  has  its  analogue  among  the  Cmstacea,  M'hilst  in  none 
of  the  Vermes  is  a  similar  indurated  cuticle  to  be  foimd. 

''Vermes  are  destitute  of  striated  muscles;  but  Rotifera,  equally  with 
Cmstacea,  possess  them.  The  movements  of  many  species  recall  in  a  striking 
manner  those  of  Crustaceans.  The  nervous  system  supphes  fiu'ther  evidence ; 
for  although  the  Rotatoria  have  no  pharyngeal  ganglionic  ring  and  no  chain 
of  abdominal  ganglia  proceeding  from  it,  yet  a  similar  deficiency  prevails  with 
the  Lophyropoda  and  the  Daphnice,  recognized  Crustaceans,  which  have  only 
a  cerebral  ganglion  and  radiating  nerves  like  the  Rotifera ;  consequently  it 


OF  THE  ROTATORIA.  469 

cannot  be  adduced  as  a  law,  that  the  highly  developed  nervous  system  of  the 
hio-her  forms  is  an  essential  character  of  the  Crustacea. 

"  The  mode  of  termination  of  the  sensitive  nerves  is  that  seen  in  Crustacea 
and  Insecta ;  but  the  like  is  not  kno^vn  among  Vermes.  Ehrenberg  pointed 
out  the  similarity  of  the  eye-specks  to  those  of  Crustacea.  The  several  seg- 
ments and  texture  of  the  ahmentary  canal  afford  no  decisive  evidence,  since 
many  Vermes  have  horny  jaws,  as  have  the  Eotifera.  The  masticatory 
apparatus  of  the  young  Daphmce  presents  a  pretty  close  resemblance  with 
that  of  Rotatoria — the  two  opposed  jaws  expanding  into  a  plate  toothed  with 
numerous  transverse  ridges,  like  those  of  Lacinularia.  The  stomach-glands 
probably  have  their  analogues  in  the  lobed  glandular  appendages — the  so- 
called  '  salivary  glands  '  of  Cirripedia. 

"  Similar  organs,  however,  exist  in  many  dorsibranchiate  Vermes ;  and  like- 
^vise  in  many  Vermes  and  lower  Crustacea  the  liver  is  represented  by  large 
cells  with  peculiar  contents,  situated  in  the  walls  of  the  stomach  and  intes- 
tine. The  absence  of  an  intestine  in  a  few  Rotifera  may  appear  opposed  to 
their  Arthropodous  type ;  yet  in  the  Neiu'opterous  larva  of  Myrmeleo  the 
faeces  are  discharged  by  the  mouth,  and  the  rectum  itself  is  transformed  into 
a  spinning  organ.  Moreover,  the  intestinal  canal  of  many  Eotifera,  e.  g. 
Eucldcmis  and  StejjJianoceros,  recalls,  in  its  peculiar  bell-hke  movement,  the 
exactly  similar  character  of  the  intestine  of  certain  parasitic  Crustacea 
{Achtheres,  Tracheliastes,  &c.). 

'"  The  substance  regarded  as  urinarj-  concretions  is  evidently  closely  re- 
lated to  that  formed  in  the  larva  of  Ci/cloj^s ;  but  no  such  j)oint  of  resemblance 
is  found  among  Vermes. 

"  Lastly,  the  anatomical  and  physiological  phenomena  of  sexual  life  greatly 
favour  the  Crustacean  relationship.  Several  minor  particulars  may  be  alluded 
to — such  as  the  j)roduction  of  two  kinds  of  ova  (indeed  the  winter  ova  of 
Tr'iarthra  have  a  great  hkeness  in  the  construction  of  the  shell  with  the 
ephippial  ova  of  Daj^hnia),  the  fact  that  many  species  cany  their  eggs  about 
with  them  (although  it  is  tnie  the  same  is  seen  among  Vermes,  for  instance 
Clepsine),  and  the  occurrence  of  coloured  oil- corpuscles  in  the  yelk  of  not  a 
few  Rotatoria — all  indicating  a  Crustacean  type.  The  striking  analogy  be- 
tween the  male  (in  some  sense  aborted)  Rotatoria  and  the  males  of  many 
Cnistacea  is  one  of  far  higher  import.  It  is  only  necessary  to  call  to  mind  the 
diminutive  parasitic  males  Nordmann  discovered  in  the  females  of  Achtheres, 
BrachieUa,  Chondracanthus,  and  Anchorella,  and  such  as  Kroyer  foimd  in 
other  Lernceopoda  and  Lerncece. 

^'  Moreover,  the  embryonic  histoiy  of  Rotifera  is  in  favom^  of  the  alHance, 
— viz.  the  imperfect  development  of  the  young  of  several  species,  on  their 
emergence  from  the  egg,  and  the  necessary  metamorphosis  they  undergo 
before  attaining  the  adult  condition.  Lastly,  the  diminution  or  even  com- 
plete disappearance  of  the  eyes  after  birth  fiu-ther  indicates  an  analogy  with 
certain  Crustacean  forms. 

"  ^\Tiilst  the  foregoing  considerations  approximate  the  Rotifers  to  the 
Crustacea,  the  nature  of  the  resj^iratory  apparatus  and  the  presence  of  the 
yibratile  ciHa  separate  the  two,  and  assimilate  the  Rotatoria  to  Vermes ;  yet 
in  both  these  particulars  they  make  an  equal  approach  to  Echinodermata, 
inasmuch  as  the  pecuhar  vibratile  organs  of  Synajyta  du/itata  appear  to  be 
similar  structures  with  the  vibrating  organs  (tags  or  gills)." 

Now,  argues  Ley  dig,  it  seems  but  just  to  allow  the  sum  of  the  resem- 
blances to  any  class,  if  greater  than  that  of  the  differences,  to  determine  the 
systematic  position.  If  this  be  granted,  as  the  sum  of  resemblances  of  the 
Rolifera  with  the   Crustaceans   seems   assuredly  greater  than  that  of  their 


470  GENEKAL  HISTOEY  OF  THE  INFUSOKIA. 

differences  from  them,  their  alHance  with  them  must  be  admitted.  Making 
due  allowance,  therefore,  for  the  vibratile  cilia  and  the  peciihar  respiratory 
apparatus  of  Rotatoiia,  Leydig  would  constitute  them  a  special  class  of 
Crustacea,  under  the  name  of  Ciliated  Cnistacea. 

The  foregoing  arguments  of  Leydig  for  the  Crustacean  nature  of  Rotatoria 
have  been  severally  met  and  replied  to  by  C.  Vogt,  in  a  recent  paper  "  On 
the  Systematic  Position  of  the  Rotifera  "  {Zeitschr.  1855,  p.  193).  The  ob- 
jections advanced  are  these  : — 

That  Leydig  assigns  an  undue  importance  to  external  resemblances  ;  and 
that,  as  to  movements,  there  is  as  much  similarity  between  those  of  PhilocUna 
and  a  leech,  as  between  those  of  any  other  of  the  Rotifera  and  the  skipping 
motions  of  Entomostraca.  The  figm^e  is  no  actual  evidence  of  affinity :  no 
perceptible  likeness  exists  between  fixed  Rotifera,  or  a  sac-hke  Notommata 
and  a  Crustacean,  whilst,  on  the  contrary,  an  imdoubted  similarity  prevails 
between  a  Stejpluuioceros  and  a  Bryozoon ;  and  between  Notommata  tardigrada 
and  many  of  the  Vermes  the  resemblance  is  more  pronoimced  than  that  be- 
tween any  of  the  Rotatoria  and  a  water-flea.  Besides,  there  are  Vermes  of  a 
smooth,  oval,  discoid,  and  expanded  figm^e,  and  others  with  bodies  not  less 
clearly  di\'ided  into  regions  than  the  Rotifera. 

An  annulate  articulation,  like  that  of  the  pseudopodium  of  Rotifera,  is  also 
a  feature  seen  among  Annelida ;  and  the  telescopic  joints  and  movement  are 
witnessed  in  Eunice.  It  is  the  possession  of  limbs,  each  consisting  of  several 
segments,  which  is  characteristic  of  Articulata,  both  in  the  full-grown  and 
in  the  larva  condition,  and  not  an  asymmetrical  process  actually  forming  but 
a  single  segment.  Further,  spines  and  hooks,  in  some  degree  moveable  like 
the  pincer-processes  on  the  pseudopodium  of  Rotatoria,  occiu'  in  many  Vermes, 
especially  among  the  parasitic  species.  Lastly,  a  pair  of  jointed  locomotive 
organs  is  never  foimd  among  Rotatoria  at  any  period  of  theii-  existence.  The 
assertion  that  the  thickening  of  the  integument  as  a  lorica  is  not  seen  in  any 
Vermes  is  correct,  if  the  constitution  of  the  lorica  of  one  piece  be  a  necessary 
feature,  although  the  thick  cartilaginous  tube  of  Gordiacece  and  the  firm  in- 
tegument of  many  other  Annehds  may  be  adduced  as  analogous  conditions. 
But  if  a  lorica  may  be  composed  of  several  pieces,  the  whole  family  of  marine 
Annelida,  in  which  the  skin  is  hardened  into  a  firm  shield,  may  be  cited  as 
homologous.  To  Ley  dig's  remark  that  he  knows  of  no  Vermes  with  a  lorica, 
the  rejoinder  may  be  made,  that  no  Crustacean  is  found  enveloped  in  a  gela- 
tinous sheath,  like  Notommata  cenfrura,  whilst,  on  the  contrary,  such  an 
investment  is  common  among  Vermes,  and  especially  exemplified  in  Si^hono- 
stomum. 

Striated  muscles  are  not  unknown  in  Annelida ;  they  have  been  seen  in 
Salpa ;  and  in  some  Radiata  the  particles  of  muscles  separate  as  so  many 
disks.  Moreover,  such  muscles  occur  in  other  Invertebrata  besides  Crustacea, 
and  they  therefore  furnish  no  real  argument  for  allying  Rotifera  with  the 
latter. 

The  nervous  system  lends  no  support  to  Leydig's  views,  as  he  professes  it 
does.  A  coalesced  cerebral  gangUon  sending  off  neiwes  to  depressions  in  the 
cuticle  armed  vdth  bristles,  finds  no  analogy  among  the  lower  Crustacea,  but 
exhibits,  on  the  other  hand,  an  actual  identity  of  structure  ^vith  the  nervous 
system  of  the  Turbellaria.  The  same  resemblance  is  apparent  among  all  the 
Cestoidea,  the  Nemertm,  Planar ia',  and  Trematoda.  Again,  the  like  degrees 
of  development  of  eye-specks,  from  a  simple  heap  of  pigment  to  a  definite 
organ  with  a  refracting  medium,  is  illustrated  by  all  those  sections  of  the 
class  Vermes,  as  Quatrefages  shows  in  his  figm-es  of  the  Nemertce.  The  mode 
of  termination  of  the  nerves  described  by  Leydig  in  Rotatoria  and  Crustacea 


OF  THE  EOTATOEIA.  471 

is  also  seen  in  Vermes ;  and  in  general  the  organization  of  the  nervous  sy- 
stem is  much  more  in  accordance  with  that  of  Cestoidea  than  mth  that  of 
the  lowest  Crustacea.  Leydig  remarks  the  great  similarity  of  the  maxillary 
apparatus  of  young  DapJinice  Tvdth  that  of  some  Eotatoria,  but  forgets  that  a 
similar  structui'e  occm^s  in  many  Vermes.  On  the  other  hand,  there  are  no 
Crustacea  which  can,  like  several  Notonimatce,  protrude  the  maxillary  organs 
as  prehensile  instruments ;  yet  it  is  a  common  phenomenon  with  many  Vermes. 
Further,  in  no  Articulata  are  the  anus  and  rectum  wanting,  as  happens  ^^dtli 
some  Rotatoria  ;  for  although  in  the  larva  of  Myrmeleo,  as  Leydig  states,  the 
rectimi  is  transformed  into  a  spinning  organ,  still  the  viscus  is  present,  though 
modified  for  a  different  functional  pui-pose  :  however,  among  Vermes  such 
an  imperfect  intestinal  canal  is  common  enough.  From  the  preceding  con- 
siderations, the  structui^e  of  the  alimentary  tube  must  be  admitted  to  accord 
rather  with  that  of  Vermes  than  with  that  of  Crustacea. 

The  secreted  solid  matter  in  the  cloaca  of  embryo  Cyclops,  compared  by 
Leydig  to  the  ^'  uiinary  concretions  "  of  Rotifera,  is,  however  (unlike  them), 
produced  originally  of  a  green  coloui',  within  a  sac  on  each  side  of  the  intestine, 
but  subsequently  becomes  yellow,  and  is  discharged  through  the  cloaca.  Such 
sacs  or  cells  have  rather  the  signification  of  a  liver,  and  are  common  among 
Vermes. 

Leydig  relies  most  on  the  phenomena  of  the  sexual  system  and  the  occiu'- 
rence  of  distinct  male  animals.  But  PoJynoe,  Exogone,  and  the  Cystoneidce 
produce  both  summer  and  winter  ova,  and  carry  them  about.  And  with  re- 
ference to  the  existence  of  small  distinct  males,  Krohn  has  proved  it  in  Au- 
tolytus  prolifer,  whilst  among  Xematoid  worms  generally  a  marked  difference 
obtains  between  the  males  and  females ;  and  what,  indeed,  can  be  more 
striking  than  the  difference  between  Distoma  Okenii  and  D.  hcBmatohium  ? 
The  variation  in  form  and  structure  between  the  two  sexes  can  therefore 
furnish  no  differential  character,  seeing  that  it  occurs  ahke  in  some  Crustacea 
and  in  most  bisexual  Vermes. 

The  occurrence  of  a  metamorphosis,  and  the  shrivelling  or  obliteration  of 
the  eyes,  are  phenomena  common  to  Vermes  and  Cnistacea.  The  lai-val  Ste- 
phanoceros  is  equally  comparable  and  similar  to  the  occasional  type  of  Annelid 
larva,  having  a  frontal  cUiaiy  wreath  in  advance  of  the  eyes,  or  otherwise  to 
the  larvae  of  Nemertidix,  such  as  Alardus  caudatus,  as  to  the  embryos  of  any 
Crustacea.  Wherefore  all  Leydig's  characters,  even  where  they  indicate 
some  afiinity  with  the  Crustacea,  exhibit,  at  least,  an  equally  close  one  with 
Vermes. 

The  presence  of  vibratHe  cilia  and  the  peculiar  respiratory  organs  are,  as 
Leydig  admits,  circumstances  approximating  Rotifera  to  Annehda.  A  tor- 
tuous canal  mth  cihated  tags  occurs  in  none  of  the  Ai^ticulata,  and  is  incon- 
sistent with  the  type  of  their  water-breathing  apparatus.  At  best  there  is 
only  a  remote  analogy,  whilst  a  close  similarity,  and  even  an  identity,  is  seen 
between  such  stmctures  and  those  of  most  Cestoidea. 

The  history  of  development  is  in  favour  of  the  Annelid  alliance,  and  op- 
posed to  Leydig's  hypothesis ;  for  in  all  Crustacea  the  embryo  originates 
from  a  primitive  part  superposed  upon  the  yelk,  whilst  in  Rotifera,  in  com- 
mon with  all  Vermes,  such  a  supplementary  part  is  wanting,  and  the  embryo 
is  generated  from  the  entire  yelk. 

The  appeal  to  metamorphosis  lends  its  support  to  the  present  argument : 
for  no  trace  of  resemblance  is  perceptible  between  the  larvae  of  such  Crusta- 
ceans as  undergo  transfonnation,  having  three  pairs  of  jointed  legs  or  feet,  and 
the  embryo  stages  of  Rotatoria — for  instance,  of  Stephcmoceros,  with  ciliaiy 
wreath,  posterior  bimch  of  cilia,  lateral  eyes,  and  vermifomi  trunk ;  yet  in 


472 


GENERAL  HISTORY  OP  THE  INFUSORIA. 


all  these  particulars  it,  on  the  contrary,  assimilates  to  the  larvae  of  Vermes, 
between  which  and  the  adult  state  the  diversity  is  equally  great. 

The  accompanying  tabular  statement  given  by  Yogt  briefly  presents  the 
chief  points  of  the  discussion. 


SYSTEMATIC  POSITION  OF  THE  EOTATORIA. 


Characters    inconsistent 

Characters  common 

Characters  incon- 

Characters peculiar  Characters  not  ex- 
tr.  rr.,«fn\.pn        clusive  but  Common 

with   Crustacea    but    in 

to  Crustacea  and 

sistent  with 

accordance  with  Vermes. 

Vermes. 

Vermes. 

to  other  classes. 

1.  COiary  motion. 

Annulation     of 

Formation  of  a 

the       bodies 

lorica. 

with   telesco- 

pic segments. 

2.  Vessels  with  cili- 
ated tags. 

Structm'e  of  the 
nervous     sy- 

Structure of  the 
muscles. . 

stem  and  or- 

gans of  sense. 

3.  Development    of 
embryos  from  the 

Maxillary     ap- 
paratus. 

Structm'c  of  in- 

testinal canal. 

entire  yelk  with- 

1 

out         primitive 

part. 

4.  Typical  structui'e 
of  tlie  larvre  and 

Formation      of 

Urinary  secre- 
tion (?). 

eggs          and 

young,      without 

their     carry- 

jointed    locomo- 

ing about  by 

tive  organs. 

parent. 

5.  Total   absence  of 

Dissimilarity 

articulated  limbs 

and     imper- 

in   pairs    during 

fect  organiza- 

their entu-e  exist- 

tion    of    the 

ence. 

males. 

Cohn's  name  may  now  be  added  to  the  list  of  opponents  to  the  Crustacean 
alliance.  We  have  already  seen  (p.  447)  that  he  denies  the  occurrence  of  any 
metamorphosis  in  the  course  of  development  of  the  Eotatoria,  and  by  so 
doing  sets  aside  one  indication  Leydig  brought  forward  in  favour  of  their 
alliance  with  Crustacea.  The  following  is  a  summaiy  of  his  arguments  against 
that  relationship : — "  The  ciliated  condition  of  the  E-otifera,  their  respiratory 
apparatus,  their  nervous  system,  the  position  of  the  intestine,  and  even  their 
general  form,  are  all  of  them  circumstances  in  favour  of  their  affinity  with 
Vermes."  Cohn  can  find  no  true  articulations,  but  merely  shallow  folds  of 
the  skin  in  the  principal  portion  of  the  body ;  and  even  the  pseudopodium 
and  toes  are  not  articidated  motory  organs  (or  limbs),  but  prolongations  from 
the  common  cavity  of  the  body.  The  circumstance  of  his  having  united  the 
Tardigrada  with  the  Systolides  (Rotatoria)  indicates  Dujardin's  recognition 
of  the  affinity  of  the  latter  with  Crustacea ;  for  in  structure  the  Tardigrada 
make  an  unmistakeable  approach  to  Arthropoda  by  the  pairs  of  limbs  and 
chain  of  ganglions  on  the  abdominal  surface,  and  to  Arachnida  also  by  the 
structure  and  disposition  of  their  digestive  organs,  by  their  suctorial  mouth, 
and  by  other  details  of  organization.  Their  association  '\^dth  Rotatoria,  how- 
ever, is  not  recognized  by  any  other  naturalist  besides  Dujardin ;  and  they 
are  generally  placed  amongst  the  lowest  Arachnida,  near  the  Pycnogonidce 
and  Acarhim  (the  lowest  families  of  Arachnida)  (see  Section  V.,  Of  the  Tar- 
pigrada). 

A  still  higher  affinity  has  been  recently  claimed  for  the  Rotatoria  by  Mr. 


OF  THE  ROTATORIA.  473 

Gosse,  viz.  with  Arthropoda  and  Insects.  He  supports  this  notion  by  an 
appeal  to  the  structure  of  the  maxillary  apparatus  and  to  supposed  analogies 
of  its  several  parts  with  the  mandibles,  jaws,  &c.,  of  insects.  The  "  mastax  " 
(see  chapter  on  Digestive  Apparatus)  he  identifies  with  a  true  mouth ;  the 
<'  mallei  "  with  mandibles  ;  the  "  manubria  "  possibly  with  the  cheeks,  into 
which  the  "  mallei  "  are  articulated  ;  the  "■  rami  "  of  the  "  incus  "  with 
maxillae ;  and  the  "fidcrum  "  he  imagines  to  represent  the  '^  cardines  "  sol- 
dered together.  "VMiile  maintaining  this  connexion  with  Insecta  through 
the  maxillary  organs  in  their  highest  development,  he  suggests  their  affinity 
with  Polyzoa  by  the  same  organs  at  the  opposite  extremity  of  the  scale,  since 
the  oval  muscular  bulbs  in  Bowerhmikia  approach  and  recede  in  their  action 
on  food,  and  seem  to  represent  the  quadrigiobular  masses  of  Limnias  and 
Botifer  further  degenerated.  If  this  affinity  be  correctly  indicated,  the  in- 
teresting fact  is  apparent  that  the  Polyzoa  present  the  point  where  the  two 
great  parallel  divisions  Mollusca  and  Articulata  unite  in  their  course  towards 
the  tme  Polypi  (see  Mr.  Gosse's  valuable  paper  in  the  Phihsoplikal  Trans- 
actions, 1855).  In  a  memoir  since  read  before  the  Koyal  Society  (Phil. 
Trans.  1857)  by  this  same  distinguished  natiu-alist,  the  Crustacean  alliance 
is  further  insisted  on  upon  the  ground  of  the  sexual  pecuharities  of  the  Ko- 
tatoria.  In  this  paper  the  author  remarks  that  we  must  look,  for  a  parallel 
to  the  curious  facts  established  concerning  the  dioecious  character  of  Eotifera 
and  theii'  peculiar  males  (see  p.  455),  to  the  Crustacea.  "  The  economy  of 
the  Hectocof}jlus  of  certain  Cephalopod  Mollusca,  though  perhaps  even  still 
more  abnormal,  is  only  remotely  analogous.  Xor  is  the  parallelism  very  close 
of  those  Entozoa  in  which  the  males  are  organically  united  to  the  females,  as 
the  genera  Heteroura  and  Si/ngamus,  described  by  Professor  Owen. 

"  In  the  class  Crustacea,  however,  many  examples  occur  of  a  sexual  differ- 
ence, which  may  instructively  be  compared  ^vith  the  one  before  us.  Thus, 
among  the  Isopoda,  we  find  the  parasitic  genera  Bo^yrus,  Pliryxus,  and  lone, 
in  which  the  males  are  notably  smaller  than  the  females,  very  diverse  in 
fonn,  and  in  some  respects  inferior  in  structure.  In  the  Siphonostoma  '  the 
males  are  extremely  smaU,  and  do  not  in  the  least  resemble  the  females,' 
though  those  of  different  genera  bear  a  strong  resemblance  inter  se,  even 
when  the  females  are  very  dissimilar.  So  low  is  their  grade  of  organization, 
that  Burmeister  has  attempted  to  prove  these  minute  creatures  to  be  embry- 
onic or  larval  forms.  And,  finally,  in  the  Cirripedia,  Mr.  Darwin  has  proved 
the  existence  of  males  in  the  genera  IbJa  and  ScaJjjeUum,  which  are  very 
minute  as  compared  with  their  females,  excessively  abnormal  in  form,  and  in 
some  respects  in  an  embryonic  condition,  though  unquestionably  mature,  as 
shown  by  the  spermatozoa.  And,  what  is  still  more  interesting,  the  same 
accurate  zoologist  observes — '  After  the  most  careful  dissection  of  very  many 
specimens,  ....  I  can  venture  positively  to  assert  that  there  is  no  vestige  of  a 
mouth  or  masticatory  organs,  or  stomach.'  Again,  he  describes  the  internal 
structure  as  '  a  pulpy  mass  with  numerous  oil-globules,'  and  the  sperm- 
vesicle  as  '  a  pear-shaped  bag  at  the  very  bottom  of  the  sack-formed  animal, 
containing  either  pulpy  matter,  or  a  great  mass  of  spermatozoa,' — terms  which 
might  have  been  employed  in  describing  some  of  the  male  Brachioni. 

'•  In  all  these  analogies  I  conceive  we  may  find  additional  reasons,  to  those 
that  have  been  before  adduced,  for  assigning  to  the  Eotifera  a  zoological  po- 
sition among  the  Articulata." 

The  attempt  of  Mr.  Gosse  to  identify  parts  of  the  maxillary  mechanism  of 
Rotatoria  with  that  of  Insects,  although  praiseworthy,  is  in  our  opinion  un- 
successful, and  involves  a  considerable  stretch  of  imagination.  Moreover,  if 
the  identifications,  or  more  correctly  speaking  the  homologies,  be  correct,  we 


474  GENERAL  HISTORY  OP  THE  INFUSORIA. 

do  not  see  that  this  circumstance  is  per  se  adequate  to  establish  an  alliance 
with  the  Insecta,  particularly  when,  in  most  other  respects,  the  differences 
between  the  two  groups  of  beings  are  so  very  considerable.  Heferring  only 
to  the  particulars  mentioned  in  Vogt's  critique,  we  may  observe  that  if  the 
aberrations  of  organization  of  Eotatoria  from  the  lowest  Crustacea  render 
their  alliance  with  the  latter  more  than  doubtful,  still  less  possible  is  their 
connexion  with  the  highest  Articulata,  in  which  every  differential  character 
becomes  more  developed. 

The  arguments  and  illustrations  of  Yogt  in  favour  of  the  close  affinity 
of  Rotatoria  with  Vermes  will  to  most  minds  appear  convincing ;  but  should 
any  demand  further  evidence,  it  is  supplied  by  the  opinions  of  the  majority 
of  naturalists  and  by  the  reasons  adduced  in  their  support.  At  present  we 
will  confine  ourselves  to  the  views  and  arguments  of  Perty,  Siebold,  William- 
son, and  Huxley. 

Perty  enters  into  no  discussion,  but  merely  states  generally  that  the  posi- 
tion of  Rotifera  with  Vermes  is  indicated  by  their  want  of  jointed  feet  in 
pairs,  and  of  a  ganghonic  abdominal  chain  such  as  Crustacea  have,  whilst,  on 
the  contrary,  they  are  provided  with  external  voluntary  and  internal  invo- 
luntary cilia,  after  the  type  of  Vermes.  The  class  to  which  he  would  refer 
them  is  that  of  the  Thoracozoa  (Arthrozoa). 

Siebold  affirmed  that  the  affinity  of  Rotifera  ^\\ih.  the  Crustacea  is  but 
remote,  since  they  are,  he  conceives,  deficient  of  a  distinct  abdominal  mem- 
brane, of  limbs  in  pairs,  and  of  striped  muscular  fibre, — undergo  no  meta- 
morphosis like  Crustacea, — have  organs  of  respiration  (ciha)  both  externally 
and  internally,  and  an  epithelium  lining  the  alimentary  tube,  such  as  no  Ar- 
thropoda  or  Cnistacea  possess.  Subsequent  research  has  invalidated  a  few 
of  the  reasons  put  forward  by  Siebold,  such  as  that  of  the  absence  of  striated 
muscles ;  but  the  majority  retain  their  force. 

Prof.  Williamson  argues,  from  the  particular  instance  of  Melicerta,  against 
a  Crustacean  relationship.  His  words  are — ''  In  the  possession  of  so  highly- 
organized  a  form  of  voluntary  muscle,  in  the  investment  of  the  fasciculi  by  a 
sarcolemma,  and  in  the  existence  of  a  well-defined,  ciliated,  cellular  epithe- 
lium lining  the  alimentarj^  canal,  we  have  indications  of  an  organization  ap- 
proaching that  of  the  lower  Articulata.  The  dental  apparatus  appears  to 
constitute  a  splanchno-skeleton,  like  that  of  the  Crustacea  ;  but,  on  the  other 
hand,  the  absence  of  a  visible  nei'vous  system  removes  the  Melicerta  far  below 
the  Homogangliate  animals.  That  they  should  possess  a  nervous  system  of 
some  kind  appears  almost  a  matter  of  necessity  if  the  presence  of  a  striated 
muscular  fibre  indicates  volition ;  but  its  actual  existence  has  yet  to  be  de- 
monstrated. I  have  found  no  special  organs  of  circulation  or  respiration.  On 
watching  the  movements  of  the  small  free  cells  which  float  in  the  visceral 
cavity,  as  well  as  in  the  tail,  it  becomes  obvious  that  the  fluid  contained 
within  the  integument  moves  freely  Avith  every  contraction  of  the  body.  I 
detect  no  vessels  or  pulsating  organs.  These  facts  also  tend  to  associate  the 
animal  with  the  Acrita  rather  than  with  the  Homogangliate  Crustacea.  At 
the  same  time  its  organization  is  of  a  higher  type  than  that  of  the  Bryozoa. 
. .  .  .Again,  many  Vermes  possess  horny  jaws  not  wholly  imlike  those  of 
Rotatoria,  together  with  similar  stomach-glands,  equally  resembling  those  of 
some  lower  CiTistaceans ;  and,  moreover,  many  Vermes,  e.  g.  Clepshie,  carry 
their  eggs  about  with  them." 

Prof.  Huxley  has  very  ably  examined  the  question  of  the  affinities  of  the 
Rotatoria.  Containing,  as  his  opinions  and  illustrations  do,  many  additional 
facts,  we  shall,  at  the  risk  of  some  repetition,  add  them  to  the  preceding  dis- 
cussions and  details.     In  the  first  place,  he  adopts,  as  a  group  of  the  lower 


OF  THE  EOTATOBIA.  475 

Annulosa,  under  the  name  of  Annuloida,  the  several  families  Annelida,  Echi- 
nodennata,  Trematoda,  Tui'bellaria,  and  Nematoidea,  and  in  company  with 
these  he  would  place  the  Eotifera.  ''  The  terms  of  resemblance  (to  the  An- 
niiloida)  are  these  : — 1.  Bands  of  cilia,  resembling  and  performing  the  func- 
tions of  the  wheel  organs,  are  found  in  Annelid,  Echinoderm,  and  Trematode 
larv^.  2.  A  water-vascular  system,  essentially  similar  to  that  of  Eotifera, 
is  found  in  Monoecious  Annelids,  in  Trematoda,  in  Turbellaria,  in  Echino- 
derms,  and  perhaps  in  the  Nematoidea,  the  Cestoidea,  and  the  Nemertidae. 
3.  A  similar  condition  of  the  nervous  system  is  found  in  Turbellaria.  4.  A 
somewhat  similarly  armed  gizzard  is  found  in  the  Nemertidae ;  and  the  pha- 
r^mgeal  annature  of  a  Nereid  larva  may  well  be  compared  with  that  of 
Albertia.  5.  The  intestine  undergoes  corresponding  flexures  in  the  Echino- 
derm larvae.  There  are  therefore  no  points  of  their  organization  in  which 
the  Eotifera  differ  from  the  Annuloida ;  and  there  is  one  very  characteristic 
circumstance,  the  presence  of  the  water-vascular  system,  in  which  they  agree 
with  them." 

Prof.  Huxley  next  proceeds  to  inquire  to  which  of  the  Annuloida  the  Eoti- 
fera are  most  closely  allied,  and  in  so  doing  seeks  for  the  fundamental  types 
of  their  organization  by  an  ingenious  mode  of  demonstration,  adducing  the 
genera  Stephanoceros,  Philodina,  Notommata,  Brachionus,  and  Lacinidaria  as 
"  the  types  of  the  great  division  of  the  Eotifera,  and  of  which  whatever  is 
tme  will  probably  be  found  to  be  true  of  all  the  Eotifera."  The  result  he 
arrives  at  is,  "that  the  Eotifera  are  organized  upon  the  plan  of  an  Annelid 
larva,  which  loses  its  original  symmetry  by  the  unequal  development  of  various 
regions,  and  especially  by  that  of  the  principal  ciliated  circlet  or  trochal 
band."  After  some  further  remarks.  Prof.  Huxley  adds — "  I  do  not  hesitate 
to  di'aw  the  conclusion  "  (which  at  first  sounds  somewhat  starthng)  "  that 
the  Eotifera  are  the  permanent  forms  of  Echinoderm  larvce,  and  hold  the  same 
relation  to  the  Echinoderms  that  the  Hydi^aform  Polypi  hold  to  the  Medusce, 
or  that  Appendicidarice  hold  to  the  Ascidians. 

"  The  larva  of  Sipuncidus  might  be  taken  for  one  of  the  Eotifera ;  that  of 
Ophiura  is  essentially  similar  to  Stephanoceros ;  that  of  Asterias  resembles 
Lacinidaria  or  Melicei^taJ^ 

Again,  this  talented  naturalist  believes  that  the  Eotifera  furnish  the  link 
between  the  lower  Echinoderms  (which  otherwise  seem  to  lead  nowhere) 
and  the  Nemertidae  and  Nematoid  worms,  the  Eotifera  themselves  forming 
the  lowest  step  of  the  Echinoderm  di\dsion  of  the  Annuloida,  the  proposed 
subkiugdom  of  Cuvier's  Eadiata. 

To  elucidate  his  views.  Prof.  Huxley  has  appended  to  his  essay  a  series  of 
diagrams  sho^ving  the  essential  correspondence  between  Eotifera  and  Annelid 
or  Echinoderm  larvae. 

When  Leydig  wrote  his  memoir  on  the  Eotatoria,  he  had  the  advantage  of 
seeing  this  contribution  to  their  history  by  Prof.  Huxley,  and  has  remarked 
in  general  terms,  of  the  above  views  and  their  illustrations,  that  although  the 
ingenuity  of  the  attempt  to  prove  Eotatoria  permanent  larvae  of  Echinoderms 
must  be  admitted,  he  is  nevertheless  unable  to  adopt  the  hypothesis  of  the 
English  observer,  and  must  hold  to  his  own  idea  of  their  Crustacean  cha- 
racter. 

The  conclusion  which  it  seems  to  us  must  be  adopted  is,  that  the  Eotatoria 
belong  to  the  great  group  of  the  Eadiata  known  as  Vermes,  and  stand  in 
more  particular  relation  with  those  families  Avhich  make  up  the  proposed  di- 
vision "Annuloida."' 

We  must  now  add  a  few  observations  concerning  the  affinity  exhibited  by 
the  Eotatoria  with  the  Ciliobrachiate  Polypes  or  Bryozoa  (a  family  of  Polyzoa). 


476  GENERAL  HISTORY  OF  THE  INFUSORIA. 

This  affinity  is  particularly  marked  in  the  genus  Stephanoceros  on  the  part 
of  the  Eotifera,  and  in  that  of  Bowerhanhia  on  the  side  of  the  Bryozoa. 
The  members  of  the  latter  genus  live  in  an  elongated  tubular  case,  and  have 
themselves  an  elongated,  rather  club-shaped  figure.  The  case  is  transparent ; 
its  upper  portion  is  soft,  so  that  it  can  close  over  the  animal  when  retracted. 
The  head  of  the  Bryozoon  is  armed  with  several  long  processes  or  tentacles 
similar  to  those  of  Stephanoceros,  which  are  clothed  with  cilia  and  spines ; 
and  the  margin  of  the  head  itself  is  also  ciliated.  This  whole  armature  is 
retractile.  Muscles  are  distinguishable,  mo\ing  the  several  parts.  The  di- 
gestive sj^stem  comprehends  a  mouth,  oesophagus,  gizzard,  stomach,  a  gastric 
tube  or  pylorus,  and  an  intestine,  lined  with  cilia,  returning  upwards,  so  that 
the  anus  opens  near  the  mouth.  The  lining  membrane  of  the  gizzard  is 
moreover  furnished  ^dth  many  horny  teeth,  seated  on  oval  muscular  bulbs, 
which,  according  to  Mr.  Gosse  (see  p. 473),  ^'approach  and  recede  in  their  action 
on  food,  and  seem  to  represent  the  quadiiglobular  masses  of  Limnias  and  Ro- 
tifer fui'ther  degenerated."  The  Bryozoa  as  a  class  are  reproduced  by  three 
modes:  1.  by  ova;  2.  by  ciliated  gemmules;  and  3.  by  budding  (gemma- 
tion) from  the  common  stem  or  polypidom  where  they  grow.  The  second 
mode  is  not  met  with  in  BowerbanMci,  but  only  in  species  having  fleshy  or 
gelatinous  polyparies  (e.  g.  Halodacti/lus),  where  the  ciliated  gemmules  occiu' 
in  sacs,  which  appear  as  whitish  points  imbedded  in  the  general  mass.  Is  there, 
we  may  ask,  any  analogy  between  these  and  the  winter  ova  of  Eotifera,  which 
are  in  some  cases  ciliated  or  haiiy  ?  The  ovary  producing  the  ordinary  ova 
is  placed  close  above  the  stomach  ;  and  contiguous  to  it  is  the  testis,  filled  with 
spermatozoa.  The  ova  when  ripe  escape  into  the  general  cavity  of  the  body, 
•  where  they  are  surrounded  and  impregnated  by  the  spermatozoa  ;  and  after 
several  have  accumulated  about  the  base  of  the  tentacles,  they  are  at  length 
discharged  through  the  anus.  The  ova  are  remarkable  from  their  irregularity 
of  shape.  The  embryo  escapes  as  a  free  being,  not  unlike  some  ciliated  Pro- 
tozoon,  but  by-and-by  it  fixes  itself,  produces  its  pedicle,  and  assumes  the 
form  of  its  parent. 

On  comparing  this  description  of  Bowerhanhia  with  that  of  Stephanoceros, 
the  points  of  similarity  between  the  two  are  veiy  many  and  striking.  The 
points  in  which  BowerbanJcia  chiefly  differ  are — 1.  its  character  as  a  member 
of  a  compound  mass  or  polypary  from  which  it  may  itself  have  grown  as  a 
bud,  whilst  reproduction  by  gemmation  is  unknown  among  Eotifera ;  2.  the 
position  of  the  ovary  above  the  stomach,  in  close  proximity,  with  an  evident 
testis ;  3.  the  apparent  absence  of  an  oviduct,  and  the  consequent  escape  of 
the  ovum,  followed  by  its  fertilization,  mthin  the  general  cavity  of  the  body ; 
4.  the  imperfect  development  of  a  maxillary  apparatus ;  5.  the  absence  of  a 
water- vascular  system  ;  6.  the  greater  length  and  stiffness  and  more  slender 
figure  of  the  tentacles  or  arm-like  processes  of  the  head  ;  and  7.  the  different 
disposition  of  the  cilia  upon  them — for  these  in  Stej^hanoceros  are  arranged 
in  little  bunches  or  whorls  at  short  distances  from  each  other. 

But  several  of  these  distinctive  particulars  lose  much  of  their  force  from 
other  comparisons  and  considerations.  Thus  the  absence  of  an  oviduct  is 
admitted  as  an  occasional  event  in  Eotifera ;  and  the  escape  of  the  embiyos 
into  the  general  cavity  of  the  body  has  been  stated  by  many  observers  to 
occur  in  Stephanoceros ;  Leydig,  however,  denies  this  ;  yet  the  birth  of  the 
young  in  Philodina  and  their  active  life  mthin  the  body  of  the  parent  may . 
present  the  analogy  in  request.  It  cannot  be  affirmed  with  certainty  that 
BoiuerbauMa  is  unlike  Stephanoceros  in  ha\dng  a  testis  #n  company  with  the 
ovary  ;  for  no  male  Stephanoceros  has  yet  been  found,  and  some  doubtful 
structures  have  been  by  some  assumed  to  represent  the  testicle.     To  cite  yet 


OF  THE  ROTATORIA.  4/7 

another  circumstance,  a  water-vascular  system  is  indistinct  in  Steplianoceros, 
and  would  be  overlooked,  as  Leydig  remarks,  did  not  the  knowledge  of  its 
form  and  of  its  existence  in  other  Kotatoria  direct  in  the  search  for  it ;  and,  on 
the  other  hand,  such  a  structure  has  not  been  sought  after  in  Boiverhanlcia. 

These  and  other  considerations,  which  might  easily  be  added  to,  lessen  the 
differential  characters,  and,  together  with  the  many  undoubted  points  of  re- 
semblance between  Boiverhanlcia  and  Steplianoceros,  incline  us  to  the  very 
prevalent  opinion  that  there  is  a  real  affinity  between  Rotifera  and  Bryozoa, 
although  we  would  not  go  so  far  as  some  naturalists  and  place  the  genus 
Steplianoceros  among  the  latter. 

Huxley  entertains  an  adverse  opinion,  and  believes  that  "  there  is  a  funda- 
mental error  in  approximating  the  Polyzoa  and  the  Rotifera  at  all,  that  the 
resemblance  between  Steijhanoceros  and  a  Polyzoon  is  very  superficial,  and 
that  the  relations  between  the  Polyzoa  and  the  Rotifera  are  at  the  best  mere 
analogies." 

The  resemblances  between  the  Rotatoria  and  the  Ciliated  Protozoa  are 
merely  superficial.  Vaginicola  is  enclosed  in  a  transparent  sheath,  like  a 
Floscularia  or  a  Tuhicolaria ;  the  urceolated  indi\iduals  of  Ophrydium  are 
grouped  into  gelatinous  balls,  like  those  of  ConocMlus ;  the  ciliary  wreath 
about  the  head  of  Vorticella,  Stentor,  and  Vaginicola  makes  an  approxima- 
tion to  that  of  Rotatoria ;  and  the  contractile  muscular  pedicle  of  Vorticella 
and  Zoofhamnium  recalls,  in  some  respects,  the  retractile  pedicles  of  the  fixed 
Rotatoria. 

A  connecting  link  is,  however,  supplied  between  the  Ciliated  Protozoa  and 
the  Rotatoria  by  most  genera  of  the  family  Ichthydina,  which  Ehrenbei'g 
indeed  numbered  among  the  latter  class.  This  great  microscopist  had  but  an 
imperfect  acquaintance  with  their  organization  ;  and  at  the  present  time  our 
knowledge  of  it  is  far  from  complete.  The  genera  referred  to  are  IchtJiydiimi 
and  Cha^tonotus ;  and  perhaps  Mr.  Gosse's  genus  Saccidus  should  be  united 
with  them.  The  genus  Glenopliora  of  Ehrenberg  is  not  recognized  by  most 
naturalists. 

They  differ  from  Rotatoria  in  having  no  transverse  joints  or  folds  to  the 
body,  no  water- vascular  system,  no  appreciable  muscles  or  nerves,  whilst 
the  ciliary  wreath  is  on  the  model  of  Ciliated  Protozoa,  and  the  alimentary 
canal  after  the  type  of  that  of  Nematoda  and  of  Anguillula.  The  vibratile 
ciha  extend  also  over  the  abdominal  surface  of  Ichthydium,  and  over  both 
the  ventral  and  dorsal  of  Clioitonotus,  Lastly,  according  to  M.  Schultze  they 
are  hermaphrodite,  and  have  pin-shaped  spermatozoa.  These  peculiarities  of 
organization  have  induced  observers  generallj-  to  exclude  these  genera  from 
Rotatoria.  Dujardin  has  found  a  place  for  them  along  mth  Coleps  ;  and  a 
doubtful  subgeniLS  he  named  Planariola,  as  a  subclass  of  Ciliated  Protozoa, 
unlike  the  rest  of  this  class  in  being  symmetrical. 

Another  link  between  Rotifera  and  the  Ciliata  is  to  be  found  in  the  peculiar 
genus  Dysteria,  which  Prof.  Huxley  referred  to  the  Euplota,  and  Mr.  Gosse 
to  the  Monocercadeoi  among  the  Rotatoria  (see  p.  387). 

CLAssiTicATiojiT. — Siuce  no  observers,  prior  to  Ehrenberg,  duly  recognized 
the  Rotatoria  as  a  class  distinct  from  the  Protozoa,  we  may  at  once  commence 
with  an  analysis  of  the  classification  he  has  proposed. 

^  This  was  based  on  the  apparent  structure  of  the  rotary  organ,  of  which  he 
distinguished  two  types  :  1.  in  which  the  circlet  of  cilia  is  complete — Mono- 
troclia ;  2.  in  which  it  is  diWded  into  two  or  more  segments — Sorotrocha. 
Each  typical  form  was  subdivided ;  the  first  into  Holotroclia,  in  which  the 
ciliated  ring  is  entire,  and  Schizotrocha,  in  which  the  wreath  is  notched.  The 
iiccond  {SorotroeJia)mio  PoJyfrocha,  with  a  compound  wreath  of  several  lobes 


478 


GENERAL  HISTORY  OF  THE  INFUSORIA. 


or  secondary  circlets,  and  into  Zygotroclia,  where  the  organ  consists  of  two 
(a  pair  of)  symmetrical  wreaths. 

The  further  division  of  these  sections  into  families  was  founded  on  the 
circumstance  of  the  animals  being  either  loricated  or  not  loricated ;  and  the 
distribution  into  genera  was  made,  primarily,  according  to  the  number  and 
disposition  of  the  red  eye-specks,  and  in  a  secondary  degree,  according  to 
the  characters  of  the  jaws  and  teeth,  or  of  those  of  the  foot-process,  or  other- 
wise, more  rarely,  of  the  lorica. 

This  classification  we  present  in  a  tabulated  form  for  convenience  of 
reference. 


CLASS  ROTATOEIA,  ACCOEDING  TO  EHRENBERG'S  SYSTEM. 


FAMILIES. 

lUoricated : 
thydina    . . 


Ich- 


Loricated:  CEcistina 


SECTION  I.  MONOTROCHA. 


'  eyes  absent 


GENERA. 

hail- absent    (  with  truncated  foot Ptygura; 

[  with  lorked  foot Ichthydium. 

hair  present     Chaetonotiis. 

Glenophora. 

f  loricae  distinct (Ecistes. 

[  loricoe  agglomerated  Conochilus. 


Illoricated : 
lotrochaea 


eyes  absent Cyphonautes. 

Tone  eye     Mierocodon. 


eyes  present 


[  two  eyes  Megalotrocha. 


Loricated :  Floscu- 
lariasa  


Euchlanidota...  eyes  absent 


'^eyes  absent Tubicolaria. 

one    eye    (when 

young)     Stephanoceros. 

[  rotarv  orffan  bifid  I  ^'^^^^^  distinct Limnias. 

two   eyes  (when  J  J      S  |  urceoli  agglomerate  Lacinularia. 

young)     1  rotary  organ  4-fid  Melicerta. 

[  rotary  organ  5-6-fid  Floscularia. 

SECTION  II.  SOROTROCHA 
Division  I.  Polytrocha. 

{no  teeth  Enteroplea. 
f    fv,           r  jaw  many-toothed  Hydatina. 
^^^^'^ I  jaw  one-toothed Pleurotrocha. 

f  frontal Furcularia. 

foot  styliform Monocerca. 

r  frontal  cilia  alone  Notommata. 

one  eye    . . .  -^  cervical     \  foot  furcate  \  do.        with  styles  Synchaeta, 

[  do.         with  imcini  Scaridium. 

foot  absent ;  body  with  lateral  cirrhi. .  Polyarthra. 

(\      .  ■,       (  foot  furcate Diglena. 
irontal ...  I                             r  drrhi  on  neck Triarthra. 
1  ^«^t  ^^yl^^^^^  1  cirrhi  wanting Ratulus. 
cervical    . .  .foot  furcate Distemma. 

r Triophthalmus. 

three  eyes     \  Eosphora. 

[ Otoglena. 

eyes  numer-  f Cycloglena. 

ous   I Theorus. 

'  Lepadella. 
Monostyla. 
Mastigocerca. 
Euchlanis. 
Salpina. 
Dinocharis. 
Monura. 
Colurus. 
Metopidia. 
Stephanops. 
Squamella. 


OF  THE  ROTATORIA.  479 

Division  II.  Zygotrocha. 

FAMILIES.  GENERA. 

(  f  with  a  proboscis  and  foot-processes CaUidina. 

,       ,       without  proboscis :    no  f      ,  j-  i  j  -rr   n  • 

eyes  absent  j      i,orn-like      processes     ^^^^^^  ^^^^^  P^f  ^^^.^    .     Hydrias. 

[     on  the  foot  .  1  ^^-  ^°*  P^^^led  Typhhna. 

Pliilodinsea  i  (  i  ^o^*  ""^^^  horn-  f  terminal  toes  two  . . .  Rotifer. 

two  frontal   '      ^^®  processes  \  do.  three  Actinurus, 

eyes  present  -l  1  foot  without  such  processes  ;  terminal 

I  L     toestwo  Monolabis. 

1^  two  cervical     Pliilodina. 

/eyes  absent foot  furcate Noteus, 

I  J  Brachionaea  j.  J  one  (cervical)  {^ot  absent Anuraea. 

^1  I  eyes  present -^         ^  ^    [  foot  furcate Brachionus. 

^  \  [  [  two  (frontal),  foot  sty liform Pterodina. 

Many  serious  objections  attach  even  to  the  fundamental  principles  which 
Ehrenberg  has  adopted  in  his  systematic  distribution  of  Eotifera.  Leydig 
has  well  argued  against  the  existence  of  an  actually  compound  trochal  disk 
(p.  398) ;  and  to  designate  the  peculiar  ciliated  organs  of  Floscularia  and 
Stephanoceros  simple  notched  wreaths  is  certainly  a  misnomer,  and  conveys 
an  erroneous  impression. 

The  employment  of  the  "  loricated  "  and  "  iUoricated  "  condition,  as  un- 
derstood by  Ehrenberg,  in  the  construction  of  families,  is  even  more  faulty; 
for,  as  before  observed  (p.  394-5),  he  uses  the  term  "  lorica  "  so  loosely,  that 
it  designates  no  one  special  structure.  The  existence  and  position  of  eye- 
specks,  as  characteristic  of  genera,  are  very  uncertain  and  insufficient.  These 
eoloui-ed  specks,  especially  when  numerous,  are  not  constant  either  in  number 
or  position ;  they  disappear  with  age  in  numerous  instances,  in  some  even 
before  the  adult  condition  is  attained ;  they  may  be  deficient  from  various 
external  circumstances  of  development ;  and,  in  general,  they  have  not  that 
importance  in  the  organization  and  hfe  of  the  Rotatoria  which  can  warrant 
their  employment  as  generic  distinctions.  The  formation  of  the  jaws  and 
the  number  of  the  apparent  teeth  might  afford  valuable  characteristics ;  but 
they  are  facts  difficult  of  determination  on  account  of  the  minuteness  of  their 
pai-ts.  From  the  above  considerations  it  is  evident  that  the  descriptions  of  the 
Berhn  Professor  are  open  to  much  question,  and  the  generic  characters  based 
on  them  uncertain. 

That  this  artificial  system  of  Ehrenberg  is  erroneous,  is  also  evidenced  by 
the  separation  of  undoubtedly  allied  forms  which  it  often  entails.  This  evil 
involves  another,  that  of  the  unnecessary  multiplication  of  genera  and  of  di- 
stinctive names.  Thus  Dujardin  rightly  insists  on  the  erroneous  distribution 
of  a  naturally  single  genus,  from  the  really  unimportant  variation  in  the 
number  of  coloured  specks,  into  the  several  genera  Lepadella,  Metoj>idia, 
Stephanops,  and  Squamella ;  and  also  indicates  the  division  of  the  families 
Philodincea  and  Hydatincm  as  carried  too  far.  On  the  other  hand,  the  ex- 
tensive genus  Notommata  comprehends  many  veiy  dissimilar  animals,  including, 
for  instance,  not  only  such  as  possess  the  typical  alimentary  canal  of  the 
Rotifera,  but  also  those  recently  discovered  forms  that  diverge  from  that  type 
in  wanting  a  separate  anal  outlet.  Such  a  genus  requires  revision.  The 
same  may  be  said  of  the  genus  Diglena.  In  the  opinion  of  many  naturalists, 
the  Berlin  Professor  falls  into  an  additional  error  in  admitting  the  family 
Ichthydina  among  the  Rotatoria.  In  fine,  the  result  of  modern  research  is  to 
call  equally  in  question  several  of  the  subdivisions  and  genera  which  he  has 
instituted. 

Although  the  defects  and  errors  of  Ehrenberg' s  system  be  generally  ad- 


480  GENERAL  HISTOKY  OF  THE  INFUSORIA. 

mitted,  yet  several  writers,  such  as  Siebold,  Perty,  and  Gosse,  have  been  con- 
tent to  employ  it  in  the  absence  of  a  better.  Indeed,  before  a  correct  natural 
classification  of  the  Rotatoria  can  be  made,  the  organization  of  each  inde- 
pendent form  must  be  investigated,  and  the  signification  and  relative  import- 
ance of  its  parts  determined. 

Various  temporary  arrangements  have  been  suggested.  Ehrenberg  himself 
indicated  a  division  of  the  class  according  to  the  form  and  disposition  of  the 
ahmentary  canal,  and  another  according  to  the  structure  of  the  dental  appa- 
ratus. Both  these  are  unsatisfactory  and  artificial ;  and  even  theii'  author 
was  compelled  to  admit  that  genera  and  species  were  thereby  associated  in 
alliances  quite  diff'erent  from  those  they  occuj^ied  in  his  accepted  system. 

Dujardin  considers  that,  "  in  the  present  state  of  science,  we  do  not  possess 
the  elements  of  a  definite  classification  ;  "  and  therefore  proposes,  as  a  merely 
provisional  scheme,  four  grand  divisions  of  the  Rotatoria,  including  the  Tardi- 
grada:  viz.,  1.  those  which  live  fixed  by  their  posterior  extremity;  2.  those  which 
have  but  one  mode  of  locomotion,  and  are  always  swimmers ;  3.  those  which 
enjoy  two  modes  of  progression — by  crawling,  after  the  manner  of  leeches,  and 
by  swimming  ;  4.  those  which  creep  by  moveable  imcini  on  their  lower  sm-- 
face,  and  are  destitute  of  cilia.  It  is  the  Tardigrada  which  constitute  this 
fourth  division ;  and  they  so  far  differ  from  Rotatoria,  particularly  in  the  ab- 
sence of  a  ciliary  apparatus  and  the  presence  of  rudimentary  feet,  that  their 
alliance  with  the  latter  is  generally  objected  to ;  even  Dujardin  himself  views 
it  as  of  doubtful  propriety. 

The  classification  of  Dujardin,  omitting  the  Tardigrada,  is  as  follows  : — 

FamiHes. 

,    ^.     ,  „  f  Flosculariens. 

1.  Fixed  forms   |  Melicertiens. 

r  Brachioniens. 

2.  Having  one  mode  of  locomotion,  viz.  by  swimming -j  Furculariens. 

[  Albertiens. 

3.  Having  two  modes  of  locomotion :    1.  by  swimming ;  |  jjqtiferes. 

2.  by  crawhng J 

For  the  further  division  into  genera  we  must  refer  to  Dujardin's  work. 
The  system,  as  Leydig  remarks  of  it,  is  founded  on  a  correct  principle,  and 
recommends  itself  by  its  simplicity.  The  groups  of  individuals  it  brings 
together  generally  consort  by  natural  affinities  ;  still  some  are  exceptional  and 
aberrant,  and  occur  as  disjecta  membra. 

Leydig  makes  the  attempt  to  form  a  di\ision,  primarily  according  to  the  form 
of  the  body,  and  secondarily,  to  the  nature  and  the  presence  or  the  absence 
of  the  foot-process.  There  are  three  primarj^  fonns  : — 1.  in  which  the  figure 
is  club-shaped  or  cylindrical ;  2.  in  which  it  is  saccular ;  3.  in  which  it  is 
compressed.  The  accompanying  plan  represents  in  full  the  system  in  ques- 
tion.    The  Ichtliydhia  are  omitted. 

LEYDIG'S  CLASSIFICATION. 

A.  Figure  club-shaped  or  cylindrical. 

I.    With  a  long,  transversely  wrinMed,  attached  foot. 

In  tliis  section  are  comprised  the  families  (Ecistina,  Megalotrochcpa,  and 
FloscuIaricBa  of  Ehrenberg,  excepting  the  genera  Pfygura,  Glenoi)hora, 
Cyphonautes,  and  Microcodon.     The  last  belongs  to  another  section ; 
and  the  other  tlu'ee  are  incomplete  forms. 
II.   With  a  long,  jointed,  telescopic,  and  retractile  foot. 

Is  represented  by  the  family  Fhilodincea  (Ehr.). 
III.    With  a  long,  jointed,  not  retractile  foot. 

Includes' the  genera  Scaridiian  and  Dinocharis  (Ehr.). 
IV.    With  a  short  foot  and  long  foot-processes. 

Includes  the  genera  Moriocerca,  Furciilaria,  and  Microcodon  (Ehr.).  and  the 


OF  THE  ROTATORIA.  481 

species  Notoinmata  Tigris  and  N.  longiseta  (Ehr.).   Leydig  surmises  that 
Microcodon  is  a  male  animal. 
V.    With  a  short  foot ;  the  foot-processes  equal  to  the  foot  in  lengthy  or  but  slightly 
shorter  or  longer. 

Comprises  the  genera  Hydatina,  Pleurotrocha,  Biglena,  Batulus,  Distemma, 
Triophthalmus,  Eosphora,  Cycloglena,  Theorus,  Synchtefa  (Ehr.),  and 
Lindia  (Duj.);  together  with  the  species  Notommata  Ticba,  N.  petro- 
myzon,  N.  saccigera,  N.  Copeus,  N.  centrura,  N.  brachyota,  N.  collaris, 
N.  Najas,  N.  aurita,  N.  gibba,  N.  ansata,  N.  decipiens,  N.  Felis,  N.  para- 
sitica, N.  tripus  (Ehr.),  N.  tardigrada  (Leydig),  N.  vermicularis  (Duj.), 
N.  roseola  and  N.  onisciformis  (Perty),  and  the  Furcularia  Rheinhardtii 
(Ehr.),  which  is,  however,  actually  a  Notommata.  The  genus  Lindia 
(Duj.)  is  doubtful ;  and  that  of  Enteroplea  (Ehr.)  is  the  male  of  Hyda- 
tina senta. 
yi.   Without  a  foot. 

Is  represented  by  the  genus  Albertia  (Duj.). 

B.  Figure  saccular. 

I.   With  a  short  foot. 

Such  are  the  species  Notommata  clavulata'^,  N.  Myrm^leo,  N.  Syrinx,  and 
Biglena  lacustris. 
II.   Without  a  foot. 

Includes  Notommata  anglica  (Dalrymple),  N.  Sieboldii  (Leydig),  Polyarthra 
platyptera  (Ehr.),  and  the  genera  Triarthra  (Ehr.)  and  Ascomorpha 
(Perty). 

C.  Figure  compressed. 

a.  Compressed  horizontally. 
L   With  a  foot. 

Represented  by  the  genera  Euchlanis,  Lepadella,  Monostyla,    MetopidAa, 
Stephanops,    Squaniella,    Noteus,   Brachionus,   Pterodina  (Ehr.),   and 
Notogonia  (Perty). 
II.   Without  a  foot. 

The  genus  AnurcBa  (Ehr.). 

b.  Compressed  laterally. 
Includes  the  genera  Salpina,  Mastigocerca,  Monura,  and  Colurus  (Ehr.). 

This  arrangement  of  the  Eotatoria  the  author  confesses  to  be  defective. 
In  our  opinion,  it  has  no  advantage  over  the  scheme  of  Dujardin,  and,  on 
the  other  hand,  wants  its  simplicity.  Its  basis  is  not  such  as  will  combine 
the  species  according  to  their  natural  aflElnities ;  for  there  is  no  necessary  or 
direct  relation  between  external  fonn  and  internal  organization,  and  it  is  on 
the  latter  alone  than  any  classification  can  securely  repose. 


2i 


482  GENERAL  HISTORY  OF  THE  INrUSOETA. 


Sect.  V.— OF  THE  TARDIGRADA.   ' 

Their  Structure,  Habitats,  and  Affinities. — ^The  Tardigrada  or  Tardi- 
grades  (in  German,  Wassei^bdren,  lit.  ivatei'-hears)  constitute  a  small  group 
of  animals,  first  noticed  by  Eichhorn,  and  latterly  more  fully  investigated  by 
Doyere,  Dujardin,  and  Kaufmann. 

Their  size  is  so  considerable  (from  -g^th  to  ^^^-th  of  an  inch  in  length)  that 
they  are  visible  to  the  naked  eye.  They  have  oblong,  symmetrical,  non- 
ciliated,  and  very  contractile  bodies,  admitting  of  their  rolUng  themselves  into 
a  ball,  and  of  otherwise  varying  their  figure.  The  head  is  somewhat  pro- 
duced, assuming  a  conical  or  pyramidal  figure  ;  but  they  have  no  pseudopo- 
dium  or  other  posterior  process. 

They  are  invested  by  a  resistant,  firm,  and  sometimes  horny  integument, 
composed  of  two  layers.  The  firmness  is  due  to  the  chitinous  composition  of 
the  external  lamina  or  cuticle,  which  is  not  afiected  by  caustic  alkali.  In 
Emydium,  M.  Doyere  describes  the  integument  to  consist  of  foui'  horny 
plates.  During  contraction,  the  integument  is  thrown  into  transverse  folds, 
and  the  anterior  and  posterior  segments  retracted.  Its  smface  is  generally 
smooth ;  but  in  Emydium  there  are  a  few  pretty  regularly  disposed  bristles 
(setse)  on  the  back  and  sides  ;  and  ia  the  neighbourhood  of  the  mouth  there 
are,  as  a  rule,  several  soft  flexible  processes,  palpi  or  antennae.  Numerous 
and  definite  muscles  extend  between  the  inner  skin  or  epidermis  and  the 
various  organs  and  members. 

The  under  or  abdominal  surface  is  clearly  distinguished  from  the  dorsal  by 
the  presence  of  four  pairs  of  rudimentary  feet  without  joints,  each  consisting 
of  a  nipple-like  (mammilliform)  process  supporting  on  its  extremity  from  two 
to  four  well-developed  curved  and  acute  uncini  or  hooks.  These  are  the 
locomotive  members  by  which  the  animals  crawl  upon  and  adhere  to  solid 
substances. 

The  head  is  without  a  trochal  disk  or  ciliary  wreath,  vibratile  ciha  being 
entirely  wanting.  The  mouth,  opening  at  its  extremity,  in  the  median  line, 
is  modified  so  as  to  form  a  sucking-tube  ;  it  is  narrow,  and  drawn  out  to  a 
more  or  less  fine  extremity ;  it  is  bounded  on  each  side  by  a  lateral,  rigid, 
horny,  narrow  or  linear  process — the  maxilla,  which  is  moveable  upon  a 
single  or  double  central  piece  or  fulcrum.  The  whole  organ  constitutes  a 
tube -like  sucker,  and  is  protrusile  at  wiU  beyond  the  head,  like  the  suctorial 
mouths  of  Aca?'i  and  Insecta.  On  each  side  of  the  mouth  are  the  smaU  re- 
tractile palpi  already  noticed. 

The  mouth  opens  posteriorly  in  a  pharyngeal  muscular  bulb,  furnished 
internally  with  a  horny  articulated  dental  apparatus,  serving  to  crush  food,  but 
less  highly  organized  than  in  Rotifera.  Under  the  polarizing  microscope  the 
manducatory  organs  exhibit  the  same  appearance  as  horn.  Erom  them  the 
food  passes  into  an  elongated  tubular  stomach  or  intestine,  continued  straight 
through  the  body,  and  terminating  in  an  anus  at  the  posterior  extremity.  In 
its  course  it  presents  numerous  lateral  oifshoots  or  diverticula. 

No  form  of  respiratory  or  circulatory  apparatus  has  been  detected ;  but  a 
multitude  of  granules  and  corpuscles  are  seen  to  float  freely  in  the  general 
cavity  between  the  integument  and  the  alimentary  canal,  which  Doyere  sup- 
posed to  be  concerned  in  the  processes  of  nutrition,  and  to  be  analogous  to 
blood-corpuscles.  M.  Quatrefages  states  that  the  fluid  within  the  body  is  in 
perpetual  irregiilar  motion. 


OF  THE  TARDIGHADA.  483 

The  nervous  system  is  well  developed.  It  consists  of  a  chain  of  ganglia, 
with  intercommunicating  (anastomosing)  nerve-fibres,  besides  a  central  or 
cerebral  ganglion. 

The  eyes  are  variable  and  fugacious.  The  sense  of  touch  may  be  presumed 
to  reside  specially  about  the  suctorial  mouth  and  its  contiguous  palpi.  All 
the  Tai'digrada  are  hermaphrodite.  The  ovary  is  of  large  size ;  but  the  ova, 
according  to  KoUiker  and  Frey,  do  not  in  the  course  of  development  exhibit 
a  germinal  disk :  in  this  they  differ  from  Arthi-opoda.  Few  eggs  are  pro- 
duced at  a  time,  and  are  of  large  size.  They  are,  curiously  enough,  foimd  in 
the  exuviae  or  moultings  of  the  animals ;  for  from  time  to  time  the  outer  skin 
is  cast  off.  M.  Doyere  convinced  himself  of  the  exi.stence  of  a  testis  and 
spermatozoa.  Dujardin  says  the  embryo  emerges  from  the  ovum  perfect  in 
form ;  but  Kaufmann,  on  the  contrary,  affirms  that  they  undergo  some  de- 
gree of  metamorphosis  ere  they  attain  the  adult  structure. 

The  Tardigrada  have  received  their  name  from  their  slow  movements.  They 
are  parasitic  animals,  and  live  by  sucking  the  juices  from  other  beings.  They 
are  common  upon  water-plants  and  vegetable  debris  in  ponds ;  yet  immersion 
in  water  is  not  necessarj^,  since  they  are  found,  like  Rotifers,  in  the  dust  and 
rubbish  on  the  roofs  of  houses  (a  locality  in  which  they  were  first  encountered 
by  Spallanzani),  and  especially  amid  the  small  lichens,  mosses,  &c.,  which 
spring  up  in  such  situations.  The  Bryum  is  a  favourite  moss  for  these  crea- 
tm'cs.  On  shaking  portions  of  this  or  of  other  mosses  or  aquatic  plants  in  a  basin 
of  water,  the  Tardigrada  will  fall  to  the  bottom,  and  may  be  easily  collected. 

In  most  vital  phenomena  they  very  closely  accord  with  Eotatoria ;  thus, 
like  these,  they  can  be  revived  after  being  put  into  hot  water  at  113°  to 
118°,  but  are  destroyed  by  immersion  in  boiling  water.  They  may  be  gra- 
dually heated  to  216°,  252°,  and  even  261°.  It  is  also  by  their  capability 
of  resuscitation  after  being  diied  that  they  are  able  to  sustain  their  vitality 
in  such  localities  as  the  roofs  of  houses,  where  at  one  time  they  are  subjected 
to  great  heat  and  excessive  drought,  and  at  another  are  immersed  in  water. 

0.  MiiUer  (in  1785)  seems,  from  the  name  {Acariis  Ursellus)  which  he 
imposed  on  the  species  he  then  knew  of,  to  have  rightly  conceived  their 
natural  affinity.  Ehrenberg  and  Schultze  (1834)  placed  them  among  the 
Leniece.  Dujardin  (in  1841)  advocated  their  alliance  with  the  Rotatoria,  and 
constituted  them  one  of  the  divisions  of  that  class,  under  the  name  of  "  Sy- 
stolides  Marcheurs,^^  or  creeping  Rotatoria  ;  for  he  considered  them  to  form  a 
link  between  the  Rotatoria  and  the  Helminthidae  on  one  side,  and  the  Anne- 
hda  and  Arachnida  on  the  other.  M.  Doyere  at  first  coincided  in  this  opinion  ; 
but  his  subsequent  researches  led  him  to  give  it  up  and  to  constitute  the  Tar- 
digrades  a  distinct  group.  Dujardin  himself  has,  moreover,  modified  his  first 
opinion,  as  appears  by  his  memoir  in  the  Annates  des  Sc.  Nat.  for  1851 ; 
for  he  there  remarks  that  the  Tardigrada  are  equally  allied  to  the  Rotifera 
and  to  the  Nematoid  Helminthidae,  and  that  it  is  uncertain  whether  they 
ought  to  be  referred  to  Articulata  or  Vermes.  Our  countryman  Mr.  White 
(in  a  paper  read  before  the  Linnean  Society  in  1851)  stated  his  belief  "  that 
the  so-called  Acarus  follicidcriim,  and  probably  also  Tardigrada,  are  parasitic 
Rotatoria,  with  legs  or  leg-hke  appendages  adapted  to  their  peculiar  habits, 
and  that  their  retractile,  antenna-like,  subtelescopic  appendages  may  have 
eyes  passing  through  them,  as  in  snails,  and  may  also  be  the  equivalents  of 
the  rotcB  (rotary  lobes),  but,  from  the  limited,  or  rather  the  absolutely  re- 
stricted, power  of  motion  of  these  animals,  have  neither  the  ciliary  processes 
nor  the  movements  and  economical  uses  of  the  appendages  so  characteristic 
of  most  of  the  Rotatoria." 

Perty  tells  us  that  in  1848  he  constructed  a  family  XenomorpMdWf  which 

2i2 


484  GENERAL  HISTORY  OF  THE  INFUSORIA. 

was  accepted  by  Ehrenberg,  to  compreheiid  the  Tardigrada,  the  best-known 
of  which  were  inckided  in  a  genus  Aretiscon,  so  named  by  Schrank.  His 
opinion  now  is,  that  "  perhaps  they  should  rather  be  associated  with  the  class 
Arachnida,  as  a  lower  tj-pe,  near  the  Acarinae,"  and  not  be  numbered  Tvith  the 
Crustacea,  as  he  formerly  proposed.  ''  Doyere's  figures  of  Emydium  indicate 
their  alliance  ^dth  the  Acarinse,  like  many  of  which  the  Xenomorphidce  (Tar- 
digrada) suck  the  juices  of  other  animals.  Their  development  differs  from 
that  of  Rotifera  ;  and  their  skin  is  composed  of  chitin."  This  last  distinction, 
also  insisted  upon  by  Kaufmann,  vanishes  if  Leydig  be  correct  in  his  state- 
ment that  Rotatoria  likewise  have  a  chitinous  cuticle. 

The  most  recent  writer  on  Tardigrada  we  have  met  with  is  Kaufmann 
(ZeitscJir.  1851,  p.  220),  who  has  presented  an  able  memoir  on  those  beings. 
He  indicates  the  following  distinctive  features  between  them  and  Rotatoria : 
— The  history  of  their  development  accords  with  that  of  Arthropoda,  and 
disagrees  with  that  of  Rotifera :  the  epidermis  is  composed  of  chitin,  a  sub- 
stance only  found  in  Arthropoda  (this  we  have  already  stated  is  probably  an 
error) ;  the  pairs  of  indistinctly -jointed  limbs  and  the  abdominal  chain  of 
ganglia  no  Rotifer  possesses,  whilst,  on  the  other  hand,  the  Tardigrada  have 
no  trochal  disk  and  no  vibratile  cilia,  but  possess  a  suctorial  mouth ;  lastly, 
they  are  deficient  of  a  water- vascular  system,  and  are  all  hermaphrodite. 

Cohn,  in  a  recent  paper  (Siebold's  Zeitsclirift,  1855,  p.  481),  throws  some 
doubt  on  this  presumed  monoecious  nature  of  the  Tardigrada.  Thus,  he  says, 
Doyere,  whilst  maintaining  their  hermaphrodite  character,  has  noticed  seminal 
corpuscles  (spermatozoa)  in  only  two  individuals.  On  the  other  hand,  he  men- 
tions certain  examples  in  which  the  oral  organs  were  aborted,  and  both  sucto- 
rial disk  and  maxillary  head  were  wanting  ;  this  happened  most  frequently 
in  3Iacrobiotus  Hufelandii,  and  more  rarely  in  other  species.  Another  notable 
fact  is,  that  in  the  two  closely-aUied  species,  Macrohiotus  Hufelandii  and 
Macr.  Oberhauserii,  the  ova  of  one  are  thick-shelled  and  tubereulated,  and 
those  of  the  other  thin-shelled  and  smooth.  In  these  circumstances  Cohn 
is  disposed  to  find  a  parallel  between  Tardigrada  and  Rotatoria  in  what 
relates  to  their  sexual  peculiarities, — inferring  by  this,  that,  as  in  the  latter 
family  the  sexes  are  separated,  and  ova  of  three  sorts — male,  "  summer  " 
(asexual),  and  ''winter" — are  produced,  so,  from  the  facts  indicated,  the 
Tardigrada  may  also  be  bisexual  (dioecious)  and  may  deposit  eggs  of  each 
several  kind. 

The  relation  of  Tardigrada  to  Arachnida  through  the  lowest  divisions  of 
the  latter,  Kaufmann  proceeds  to  demonstrate  by  the  following  particulars : — 
They  have  suctorial  mouths,  like  most  Acari ;  in  the  structure  and  disposition 
of  the  digestive  organs  they  agree  with  Arachnida  ;  by  the  absence  of  circu- 
latory and  respiratory  organs  they  are  aUied  to  the  Acarina  in  part,  and  to 
the  Pycnogonidce  entirely  ;  lil?:e  many  mites  (Acarina),  they  lay  few  and 
large  eggs.  But,  again,  the  occurrence  of  a  metamorphosis  to  some  extent 
detaches  them  from  the  Pycnogonidce  and  from  most  Acarina  ;  and  they 
differ  fi'om  all  Arachnida  by  being  hermaphrodite ;  however,  the  circumstance 
of  the  separation  of  the  sexes,  or  their  union  in  the  same  indi-s^idual,  in  no 
class  of  animals  can  supply  the  basis  for  constituting  family  distinctions. 
Even  among  Arthropoda  a  family  of  hermaphrodite  animals  occui's,  viz.  the 
Cirripedia.  In  this  respect  the  Cnistacea  and  Arachnida,  by  their  lowest 
members,  through  which  they  are  linked  to  other  classes  of  animals,  accord ; 
in  the  former  the  Cirripedia,  which  ally  them  with  the  Mollusca, — in  the 
latter  the  Tardigrada,  which  approximate  the  Arachnida  to  the  Annelida, 
bring  the  two  into  connexion. 

The  conclusion  therefore  is,  that  the  Tardigrada  constitute  the  lowest 
section  of  the  Arachnida,  by  the  side  of  the  Pycnogonidce  and  the  Acarina. 


PART  11. 
A  SYSTEMATIC  HISTORY  OF  INFUSORIA 


[Note. — The  several  groups  whose  general  history  is  treated  of  in  the  first  part  of  this 
work,  viz.  Baeillaria  (p.  1),  Phytozoa  (p.  HI),  Protozoa  (p.  199),  and  Kotatoria  (p.  392), 
being  independent  of  each  other,  their  respective  families,  genera,  and  species  will  not,  for 
the  reason  stated  in  the  Preface,  be  described  in  the  same  order  in  this  second  part,  but 
those  of  the  Baeillaria  will  be  printed  last.  For  an  explanation  of  abbreviations,  see  end 
of  Contents.] 


OF  THE  GROUP  PHYTOZOA  (p.  111). 

Families: — 1.  Monadina;  2.  Hydromorina ;  3.  Cryptomonadina ; 
4.  Volvocina;  5.  Vibrionia ;  6.  Astasisea. 

FAMILY  1.— MONADINA. 

(Plate  XVIII.  figs.  1  to  28.) 

The  Monadina  are  among  the  most  minute  living  creatures  which  have  been 
discovered  by  man.  They  are  (according  to  Ehrenberg)  destitute  of  an  ali- 
mentary canal,  are  iUoricated  or  sheU-less,  and  have  a  uniform  body  without 
any  appendages  issuing  from  it,  cilia  not  being  considered  as  such.  They 
increase  by  simj)le  and  complete  self- division  into  two,  foiu',  or  more  indi- 
viduals. The  uniformity  or  unvarying  appearance  in  their  external  form  (he 
says)  may  be  considered  as  one  of  the  principal  characteristics  of  this  family ; 
for  no  one  of  the  Monadina  can  voluntaiily  alter  the  shape  of  its  body,  whether 
into  a  filiform,  knotty,  or  globular  figure,  nor  can  it  extend  any  portion  of  it, 
and  then  contract  it  again.  AU  possess  organs  of  locomotion,  nutrition,  and 
propagation,  the  last  of  the  hermaphrodite  character.  Some  of  them  have  a 
rudimentary  eye ;  but  it  has  never  been  discerned  that  they  are  furnished  with 
a  vascular  or  circidating  system,  which,  however,  is  not  surprising  when  we 
reflect  that,  should  they  possess  it  (a  supposition  by  no  means  to  be  rejected), 
the  diameters  of  the  tubes  of  this  system  would  necessarily  be  of  such  extreme 
minuteness  as  to  defy  investigation.  None  but  microscopes  of  high  magnify- 
ing powers  can  display  their  structure  ;  indeed  they  cannot  be  observed 
accurately  with  a  less  ampHfication  than  500  diameters,  by  glasses  of  consi- 
derable penetration  and  good  defimtion. 

The  apparent  eye  of  some  Monadina  is  used  as  a  generic  character  for 
Microglena  (XVIII.  6),  Phacelomonas,  &c. ;  but  its  possession  does  not  prove 
the  existence  of  sensibility,  although,  as  Ehrenberg  thinks,  this  facidty  is  pre- 
sumable from  the  alternate  vibration  and  quiescence  exhibited  by  the  pro- 
boscis when  one  of  these  beings  is  in  a  place  abundantly  supplied  ^\ith  food. 

The  details  given  in  the  first  part  of  thiswork  (p.  130), of  the  natm-e  and  struc- 
ture of  the  animalcidcs  comprised  by  Ehrenberg  in  this  family,  render  it  unne- 


486  SYSTEMATIC  HISTORY  OF  THE  INEUSORIA. 

cessary  here  to  state  more  than  that  the  beings  so  grouped  together  are  hete- 
rogeneous both  in  nature  and  character,  and  partake  scarcely  any  other  features 
in  common  than  those  of  minuteness  and  the  possession  of  one  or  of  few  elon- 
gated cilia  or  filaments  as  locomotive  organs.  The  deficiency  of  characteristics 
necessary  to  constitute  a  natural  family,  and  the  absence  of  any  proof  of  the 
animality  of  the  several  genera,  were  perceived  by  Siebold,  who  rejected  the 
Monadina  from  his  group  of  Infusoria.  Agassiz  says  of  them  that  they  are 
mostly  moveable  germs  of  various  kinds  of  Algae ;  and  in  this  statement,  we 
beheve,  as  far  as  relates  to  the  majority,  he  is  correct.  Dr.  Biu-nett  (Boston 
Journ.  Mat. Hist. 18o3,Yi.^.  319)  has  the  following  remarks  on  these  topics  : — 

"As  the  family  Monadina  now  stands,  it  undoubtedly  includes  very  hetero- 
geneous elements,  particles  being  grouped  together  from  their  general  asj)ects 
rather  than  from  their  physiological  characteristics.  I  cannot  pretend  to  take 
them  up  in  that  systematic  way  in  which  they  have  been  arranged  by  Ehi^en- 
berg  ;  for  I  have  found  but  little  system  about  them,  and  for  the  most  part 
have  been  unable  to  follow  his  descriptions.  If  we  are  to  judge  of  them  by 
mere  form  and  size  alone,  I  should  say  that  the  varieties  they  present  under 
the  microscope  are  numberless.  Indeed,  in  watching  the  same  particle  for  a 
long  time,  I  have  seen  it  change  its  form  and  size  four  or  five  times,  and  each 
as  distinct  from  the  other  as  many  of  Ehrenberg's  species.  Those  which  con- 
tain chlorophyll  must,  it  appears  to  me,  in  virtue  of  that  fact,  be  regarded 
as  of  a  vegetable  nature.     As  to  the  others  this  point  would  be  doubtful." 

Again,  Dujardin,  whilst  admitting  generally  the  animal  nature  of  the  ge- 
nera in  question,  difi'ered  widely  from  the  Berhn  natm^alist  both  as  to  their 
organization  and  distribution.  Since,  however,  in  the  present  state  of  our 
knowledge,  it  is  impossible  to  fix  on  the  organisms  of  which  they  are  but  de- 
velopmental phases,  it  is  well,  for  the  purpose  of  future  identification  and 
future  researches,  to  attempt  definitions  and  descriptions  of  these  simple 
beings,  although,  as  an  artificial  and  temporary  proceeding,  the  whole  be 
doomed  to  ultimate  neglect  and  destruction.  Consequently,  we  shall  retain 
all  Ehrenberg's  genera  and  species,  which,  however  iU-defined  and  unsatis- 
factory, give  the  best  representation  we  possess  of  these  varied  and  variable 
microscopic  organisms. 

The  views  of  Ehrenberg  on  the  special  organization  of  the  Monadina  have 
been  widely  criticised  and  condemned.  The  possession  of  an  integimient,  the 
fixed  invariable  outline,  and  the  ocular  nature  of  the  red  speck,  are  statements 
which  have  encountered  the  opposition  of  Dujardin  and  of  very  many  subse- 
quent naturalists.  The  existence  of  a  mouth  and  the  recej)tion  of  coloured 
food  have  likewise  been  widely  denied,  in  accordance  with  the  prevalent 
hypothesis  of  their  vegetable  nature  as  early  phases  of  Algae  and  Eungi ;  but 
latterly  Cohn  has  witnessed  the  entry  of  coloiu^ed  particles  into  theii'  interior, — 
a  circumstance  confirmed  by  Lachmann,  who  moreover  adds  that  he  has  twice 
observed  Monadina  which  contained  a  smaU.  Diatom,  the  excretion  of  which, 
in  the  vicinity  of  the  posterior  extremity,  taking  place  soon  afterwards,  also 
made  him  consider  the  existence  of  an  anus  probable.  Schneider  remarked 
in  Ghilomonas  Paramecium  one  or  two  reddish  lines  running  from  the  inden- 
tation into  which  the  filaments  were  fixed,  to  the  opposite  end,  and,  from  a 
comparison  of  these  with  the  process  of  fission  as  seen  in  Bodo,  concluded 
that  they  were  fiurows  which  gradually  deepen  until  the  animalcule  is  bisected. 
As  during  this  process  the  being  undergoes  no  change  of  form,  except  in  be- 
coming a  little  broader,  and  the  division  takes  place  along  its  whole  length, 
the  process  must  readily  escape  observation.  The  anterior  end  is  always  a 
little  thicker ;  the  furrows  consequently  are  deeper  and  more  distinctly  recog- 
nizable in  that  part.  It  is  only  in  rare  cases,  when  the  division  has  taken  place 


OF  THE  MON.U)INA. 


487 


more  slowly  in  some  particular  spot,  that  the  two  segments  must  endeavour 
to  tear  themselves  free,  and  thus,  by  twisting  in  contrary  directions,  draw  our 
attention  to  them.  It  was  mthout  doubt  a  specimen  of  Cryptomonas  cylhidrica 
m  this  condition  which  Ehrenberg  conceived  to  be  two  individuals  adhering 
together  and  not  in  the  act  of  fissation.  Dujardin  failed  in  seeing  spontaneous 
fission  among  the  Monadina,  and  thinks  it  more  probable  that  their  multi- 
plication takes  place  by  the  separation  of  a  lobe  or  of  the  termination  of  an 
expansion,  which  his  notion  that  they  are  without  any  sort  of  integument 
presupposes  they  may,  after  the  manner  of  Amoehce,  push  out  from  their  mass. 
The  family  is  distributed  into  nine  genera,  as  follows  : — 


(  Eye  wanting 


§ 
^  ^ 


(  Swimming 


r  Single    Monas. 

[  Aggregate Uvella. 


Eye  present   \  ^^^le 


Proboscis  one  or 
two    

Proboseides     not  1 


I  Microglena. 


Chloraster. 


more  than  four  J 

Proboseides  j  phacelomonas. 

I     many    J 

^  Aggregate Grlenomorum. 

(^  Rolling Doxococcus. 

Lips  present Cliilomonas. 


Tail  present Bodo. 

Dujardin  was  unable  to  recognize  all  the  genera  of  Ehrenberg,  and  believed 
that  Microglena,  Phacelomonas,  Glenomorum  and  Doxococcus  appertain  to 
another  family,  and  that  the  distinction  between  the  genera  Polytoma  and 
Uvella  is  erroneously  deduced  from  the  supposed  fission  of  Polytoma  in  two 
opposite  directions  and  the  periodical  grouping  of  Uvella.  He  thus  reduced 
the  genera  of  Ehrenberg  to  four  in  number,  viz.  Monas,  Uvella,  Cliilomonas 
and  Bodo,  the  last  comprehending  in  part  his  Hexamita,  Amphimonas  and 
Cercomonas.     The  subjoined  table  represents  the  distribution  he  proposed : — 


MONADINA. 


Isolated 


A  Single 

FlageUiform  « 

Filament. 


Proceeding  from  the  ante- 
rior extremity. 


/^Moveable  in  its  en- 
tire length  Monas. 

Thickened,        and 

moveable     only 

I      towards  the  ex- 

\^     tremity    Cychdium. 

Proceeding  obHquely  fi-om  behind  an  anterior 

prolongation  Chilomonas. 


^ A  second  filament  or  lateral  appendage  ... 
A  second  filament  or  posterior  appendage 


Several 
Filaments. 


Two  equal  filaments,  terminating  the  rounded 
angles  of  the  anterior  extremity  


Four  equal  filaments  in  front,  two  tliicker  be- 
hind     

A  second  filament  proceeding  from  the  same 
point  as  the  flagelliform  filament,  but  thicker, 

trailing  and  retractile    

^  A  filament  and  vibratile  cilia 

.  .      r  Groups  always  free  and  whirling  

SB    B"       I  Groups  fixed  to  the  extremity  of  a  branching  polypidom 


Amphimonaa. 
Cercomonas. 

Trepomonas. 

Hexaraita. 


Heteromita. 
Trichomonas 

Uvella. 
Anthophysa. 


488  SYjSXEilATIC  HISTORY  OF  THE  INFUSORIA. 

"  These  generic  distinctions  are,  however,"  Diijardin  veiy  justly  adds, "  en- 
tirely artificial,  and  simply  intended  to  facilitate  the  naming  of  Infusoria  one 
may  have  met  with  in  such  and  such  an  infusion,  and  which,  when  better 
known,  may  prove  in  some  instances  only  varieties  of  a  single  species." 

Perty  appends  to  his  history  of  Monadina  the  following  observations : — 
"  Ehi'enberg's  Monadina  are  very  difficult  to  determine ;  many,  hke  Monas 
bicolor,  M.  CoJpoda,  M.  Enclielys,  M.  Umbra,  M.  Tiyalina,  M.  ovalis,  M.  Mica, 
M.  cylindrica,  M.  cleses,  M.  flavicans,  M.  simplex,  M.  inanis,  and  M.  scintiUans, 
appear  to  be  only  the  earher  stages  of  other  Monadina,  or  the  yoimg  stages 
of  Ciliata.  M.  Crepuseulum  forms  my  genus  Acariceum;  M.  Termo  is  a 
Cercomonas ;  M.  Guttula  and  M.  vivipara  are  most  likely  varieties  of  the 
multiform  M.  Lens  ;  M.  grandis  and  Mieroglena  monadina  are  Sporozoids ; 
Monas  ocliracea,  M.  eruhescens,  M.  vinosa,  and  probably  M.  gliscens  belong  to 
the  genus  Chromatium  (XIX.  1)  ;  M.  Punctum  is  no  other  than  the  one  fila- 
mentary variety  of  Polytoma ;  M.  socialis  goes  along  with  Cercomonas ;  M. 
tingens  is  the  young  condition  of  Chlorogonium  euchlorum  ;  Uvella  virescens 
possesses  one  filament  and  no  cilia ;  U.  Uva  may  be  a  coloui'less  variety 
of  it ;  U.  Glaucoma  scarcely  belongs  to  the  genus  Uvella,  as  it  has  always 
two  filaments  U.  Bodo  appears  a  developmental  phase  of  Euglena  viridis ; 
Polytoma  Uvella  is  equivalent  to  my  P.  Uva ;  Mieroglena  punctifera  is  un- 
kno^vn  to  me.  The  genus  Doxococcus  I  consider  untenable ;  D.  ruber  and  B. 
Pulviscidus  are  merely  resting  forms  of  Astasia ;  Chilomonas  Volvox  and  C. 
destruens  are  in  all  probability  embiyos  of  Ciliata,  and  Ch.  Paramecium  is  the 
hvahne  variety  of  my  Cryptomonas  polymorpha ;  and  Bodo  is  di\isible  into 
Anisonema  (XIX.  8)"  and  Cercomonas  (XYIII.  11,  12,  20)." 

The  new  genera  instituted  by  the  Swiss  naturahst  are  Tetramitus  (XIX. 
3),  MaUomonas  (XIX.  4),  Pleuromonas  (XVIII.  25),  Spiromonas  (XYIII. 
24),  Menoidium  (XIX.  2),  Chromatium  (XIX.  1),  and  Acariceum.  Fresenius 
accepts  two  of  these  new  genera,  viz.  MaUomonas  and  Tetramitus,  and  creates 
in  addition  two  others,  Rhabdomonas  and  Grymcea, — the  former  not  identical 
with  the  Hhabdomonads  (staff-like  monads)  mentioned  by  Ehrenberg  as  a 
group  of  his  genus  Monas. 

Respecting  the  large  contribution  by  Perty  to  the  number  of  Monadina 
catalogued  by  Ehrenberg  and  Dujardin,  the  question  arises,  whether  the 
forms  named  are  reaUy  different  and  distinguishable.  We  fear,  indeed,  that 
the  increased  number  will  rather  perplex  and  encumber  the  observer  than 
advance  his  real  knowledge  of  microscopic  forms.  StiU,  to  make  our  resume 
complete,  they  must  be  enumerated.  In  effecting  this,  the  plan  pm^sued  wiU 
be  to  describe  the  several  genera  admitted  by  Ehrenberg  first,  adding  the 
species  noted  by  others,  and  after  these  to  give  the  characters  of  genera  and 
species  constituted  by  Dujardin,  Perty,  or  any  other  naturalist:  where  the 
same  being  has  had  a  second  name  given  it,  it  will  be  added  as  a  sjTionym. 
In  the  systematic  details  we  shall  preserve  the  descriptions  and  remarks  in 
general  which  appeared  in  the  last  edition,  and  are  largely  borrowed  from 
Ehrenberg's  most  valuable  works.  These,  indeed,  are  eveiy^where  tinged 
with  the  peculiar  hj-pothesis  of  that  writer,  the  value  and  bearing  of  which, 
however,  have  been  sufficiently  examined  in  the  first  part  of  this  work  to 
render  explanations  and  corrections  here  unnecessary.  The  description, 
therefore,  of  mouths,  eyes,  stomach  sacs,  glands,  vessels,  hermaphrodite  deve- 
lopment, ova,  and  of  all  other  stiiictui'es  or  organs  of  higher  animal  organiza- 
tion, will  have  no  other  value  as  applicable  to  such  special  organs  than  that 
accorded  to  it  in  the  mind  of  eveiy  indi\idual  reader  of  the  chapter  on  the 
structure  and  functions  of  the  Monadina,  who  can  draw  for  himself  his  own 
inferences  from  the  facts  and  opinions  therein  recorded. 


OF  THE  MONADINA.  489 

Genus  MONAS  (XVIII.  1,  2,  15,  17,  19,  21).— The  animalcules  of  this 
genus — the  true  Monads — are  described  (see  table)  by  Ehrenberg  as  destitute 
of  an  eye,  with  projecting  lip  and  tail,  and  as  always  swimming  in  the  direction 
of  the  longitudinal  axis  of  the  body,  their  mouth  being  situated  at  the  anterior 
end.  It  is  another  distinguishing  character  of  the  true  Monad,  that  it  is  never 
seen  to  cluster,  like  others  of  its  family,  so  as  to  form  a  berry-like  mass ;  and 
hence  it  is  designated  single,  in  contradistinction.  Amongst  the  several 
species  distinguished,  some  few  are  green,  yellowish,  or  of  a  reddish  tint ; 
but  the  majority  are  colourless ;  coloui',  moreover,  is  not  a  characteristic  to 
be  rehed  upon.  Monads  may  often  be  present  in  water,  under  inspection,  with- 
out being  seen,  o^ving  to  the  magnifying  power  employed  being  insufficient. 
They  will  be  sought  for  in  vain  with  a  power  of  less  than  300  diameters  ;  and 
even  this,  in  some  cases,  will  be  found  insufficient.  They  are,  besides,  as  a 
genus,  difficult  to  be  accurately  determined,  not  only  on  account  of  their  ex- 
ceeding minuteness,  but  because  the  young  of  other  genera  are  so  likely  to  be 
mistaken  for  them, — for  instance,  the  young  of  the  Bacterium,  Vibrio,  Uvella, 
Polytoma,  Pandorina,  Goniuin,  &c.,  when  separated  from  their  clusters.  And 
this  difficulty  in  discriminating  them  will  be  more  likely  to  happen  when  they 
are  not  observed  whilst  undergoing  the  process  of  self- division,  or  when  seen 
in  water  containing  but  a  small  number  of  them ;  under  which  circumstances, 
however  anxious  we  may  be  to  ascertain  their  name,  we  must  often  rest  con- 
tented with  probable  sm^mise.  When  the  water  swarms  with  the  creatures, 
the  decision  vtiU  be  far  easier,  and  more  trustworthy,  since  the  characters  are 
then  more  easily  discoverable,  and  theii'  possible  variations  appreciable.  The 
observer  may,  however,  be  gTiided  to  a  certain  extent  by  the  following  rule  : — 
Suppose  that  in  a  droj)  of  water  containing  species  of  the  genus  Vibrio,  Bac- 
terium, Uvella,  or  Polytoma  (easily  distinguished  by  their  clustering  forms), 
separate  Monad-like  bodies  were  to  be  observed ;  the  probability  is  that  they 
would  be  either  single  forms,  or  the  young  of  the  clusteiing  animalcules ;  and 
if  there  were  no  great  difference  in  the  size  of  the  separate  individuals  and 
those  forming  the  clusters,  this  conclusion  would  be  generally  correct :  and 
this  rule  apphes  equally  to  those  green  Monad-hke  creatures  found  amongst 
Pandorina  and  Gonium.  Chlamidomonas  Pidvisculus,  when  young,  is  very 
deceptive,  and  may  often  be  mistaken  for  an  illoricated  and  eyeless  green 
Monad. 

The  only  locomotive  organ  which  has  been  discovered  in  the  genus  is  the 
single  fihform  proboscis  (filament)  issuing  from  near  the  mouth.  The  niuner- 
ous  cilia  sometimes  aj)parent  thereabouts  are  nothing  more  than  this  filament 
in  a  state  of  vibratory  or  rotatory  motion.  This  organ,  Ehrenberg  observes, 
has  a  twofold  office,  one  being  locomotive,  and  the  other  to  provide  the  creature 
with  food,  and  hence  may  be  called  a  purveying  organ. 

Vacuoles  are  readily  seen  in  some  of  the  species  {e,  g.  M.  Guttula  and  M. 
vivipara)  without  the  aid  of  coloured  food  ;  in  others  {M.  Termo,  M.  Guttula, 
and  M.  social  is),  its  aid  is  required. 

The  propagative  apparatus  Ehi^enberg  represented  in  M.  Guttula  and  M. 
vivipara  to  consist  of  a  vast  niunber  of  granules  formed  into  a  net-like  mass, 
dispersed  generally  throughout  the  creature,  having  a  comparatively  large 
spherical  body  (the  nucleus)  which  divides  in  the  process  of  self-fission. 

Monads  multiply  rapidly  by  self-division,  either  transversely,  as  in  Monas 
Guttula,  M.  hyalina,  M.  gliscens,  M.  Ohenii,  and  M.  socialis ;  or  longitudi- 
nally, as  in  M.  Punctum  (XVIII.  2) :  both  methods  have  been  observed  in 
M.  vivipara. 

As  the  members  of  this  genus  are  chiefly  cmious  on  account  of  their  extreme 
minuteness,  only  the  leading  characters  and  size  of  the  several  species  are 


490 


SYSTEMATIC  HISTORY  OF  THE  INTFSORIA. 


given.     Most  of  them  are  inhabitants  of  water  in  which  organic  matter  is  un- 
dergoing decomposition. 

The  Monads  of  Ehrenberg  are  arranged  under  two  divisions,  according  to 
their  external  form.  The  first  division  contains  all  those  of  a  globular  or  oval 
shape  (globular  Monads)  ;  the  second  those  of  a  lengthened  form,  the  length 
being  more  than  twice  the  breadth  (elongated  Monads). 


A. — Globulab  Monads. 

MoNAS  Crejnisculum  (xvni.  1). — The 
smallest  of  all  living  creatm'es;  of  a 
spheroidal  form,  and  hyaline,  although, 
when  seen  in  masses,  with  the  naked 
eye,  of  a  whitish  hue.  They  are  active, 
and  feed  on  animal  as  well  as  on  vegeta- 
ble substances,  and  are  found  in  water 
holding  animal  matter  in  solution ;  but 
as  decomposition  proceeds,  they  die,  and 
their  bodies  rise  to  the  surface  of  the 
water,  and  form  a  thick  and  colourless 
gelatinous  stratum.  Rarely  1-1200"  in 
diameter ;  never  larger. 

M.  Termo  (M.),  so  named  from  its 
having  been  supposed  to  be  the  limit  of 
animal  organization ;  globular,  active, 
herbivorous ;  found  in  stagnant  water ; 
increases  rapidly  where  there  is  an 
abundance  of  vegetable  matter  imder- 
going  decomposition.  1-6000"  to 
1-12000",  and  less. 

M.  Guttula  (M.). — Bound,  inactive  ; 
may  be  preserved  by  drjdng ;  12  di- 
gestive vacuoles  seen  by  the  aid  of  in- 
digo or  carmine  ;  surface  appears  granu- 
lated. In  vessels  of  water  containing 
plants  or  flowers.     1-2300"  or  less. 

M.  vivipara. — Spherical,  inactive.  In 
stagnant  water;  coloured.   1-620"  or  less. 

M.  grandis. — Spherical ;  colour  green- 
ish, except  near  the  mouth  ;  filament 
short,  l-3rd  or  l-4th  the  length  of  the 
body  ;  motion  sluggish.  In  marsh  water, 
very  rare.     1-430". 

M.  hicolor. — Globidar;  colourless,  ex- 
cepting one  or  two  green  spots  within 
it ;  attenuated  anteriorlv ;  motion  vacil- 
lating.    1-1440". 

M.  ochracea. — Globular ;  of  a  yeUow- 
ochre  colom*.  In  water-courses.  1-6000" 
at  most. 

M.  erubescens.  —  Circular ;  rose-co- 
loured ;  motion  slow  but  continued.  In 
salt  water.     1-1728". 

M.  vinosa.  —  Globular,  colour  of  red 
wine ;  motion  tremulous  ;  rejects  co- 
loured food.  In  vegetable  infusi<|iis. 
1-12000"  to  1-6000". 

M.  Kolpoda. — Colourless,  oval  or  egg- 
shaped  :  motion  vacillating.  In  water 
in  the  silver  mines  of  Siberia,     1-7200". 

M.  Enclielys. — Colourless  ;  continuous 


slow  motion.  In  marsh  water.  1-1200" 
to  1-960". 

M.  Umhra. — Ovate,  colourless ;  motion 
rapid.  Among  fi-esh  Confervae.    1-2400" 

M.  hyalina. — Ovate,  colourless;  ac- 
tive, and  seems  to  leap  or  j  imip.  In  stale 
water  in  glass  vessels.  1-6000"  to  1-2880". 

M.  gliscens. — Ovate,  colourless ;  mo- 
tion gliding.  In  infusions  of  the  sting- 
ing-nettle.    1-4500". 

M.  ovalis. — Oval,  colomless  ;  motion 
tremulous.  In  water  from  the  Anodonta 
Mollusca.     1-9600". 

M.  i^/^m. — Oval,  colourless;  rotary 
and  vacillatino-  motion.  In  clear  fresh- 
water.    1-1440"  to  1-1200". 

M.  Punctum. — Egg-shaped  ;  revolves 
on  its  longitudinal  axis  (xviii.  2)  ;  the 
lower  figure  exhibits  one  vmdergoing 
lougitudiual  division.  In  water  with 
tannin.     1-1150". 

M.  Semen. — Large,  green,  rather  obo- 
vate,  subcompressed ;  anterior  end  di- 
lated, roimded  ;  posterior  attenuated  ; 
oral  apertm-e  (!)  triquetral  beneath  the 
frontal  portion ;  vibrates  by  numerous 
cilia  (!).  Length  1-48"' ;  motion  vacil- 
lating, slow ;  a  central,  hyaline,  subglo- 
bose  gland ;  ovides  large,  green,  ovate. 
It  readily  shows  by  diffluence  the  ova, 
gland,  and  bacillaiy  spicida.  Frontal 
end  exhibits  rugae  extending  fi'om  the 
mouth.  With  deca}'ing  Sphagnum  from 
marshes,  Berlin.  Smely  this  organism 
is  not  a  Monad. 

B. — Elongated  Monads. 

M.  cylindrica.  —  Solitary,  elongated, 
colomless ;  motion  revolving.  In  salt 
water.     1-1150". 

M.  Okenii. — Elongated,  red;  motion 
revolving,  vibratory,  social.  In  running 
water.     1-2300". 

M.  deses. — Conical,  green,  solitaiy.  In 
water  fr'om  hiUs.     1-1200". 

M.  socialis.  —  Conical,  colourless,  so- 
cial.    In  water-butts.     1-700". 

M.  Jlavicam.  —  Top-shaped ;  social  ; 
motion  gliding.  In  ditch-water.  1-1720". 

M.  simplex. — Spindle-shaped ;  colom- 
less ;  motion  gliding  and  rotary.  In 
water  of  the  Nile,  and  at  Berlin.  1-1720". 

M.  inanis. — Fusiform,  colourless ;  mo- 


OF  THE  MONADINA. 


491 


M.  procUyiosa. — A  very  minute  red 
Monad,  so  named  by  Ehrenberg-  from 
its  sm-prisingly  rapid  development.  It 
is  tliis  animalcide  wbich  has  produced 
the  blood-like  spots  occasionally  appear- 
ing mysteriously  on  bread  and  other 
ist  nimibers  in  the  saltmarsh-Avater  '  farinaceous  substances,  and  which  have 


tion  vacillating.  In  stagnant  and  foul 
water.     1-3600". 

M.  scintillam. — Fusiform,  very  active ; 
motion  vacillating.  Amongst  fresh- 
water Conferv£e,  &c.  1-6000"  to  1-4600". 

M.  Dumalii. — Of  a  deep  red  colour : 


of  the  Mediterranean,  to  which  they 
give  a  deep  blood-colour.  Discovered 
by  M.  Joly. 


ever  been  a  cause  of  ten'or  to  the  super- 
stitious. Cohn  asserts  this  organism  to 
be  a  Vibrio,  and  not  a  Monas, 


Being  desirous  of  making  this  manual  as  complete  as  possible,  the  following 
species,  described  by  M.  Dujardin,  are  inserted  ;  but  it  may  be  that  some  of 
them  refer  to  Monads  akeady  characterized,  but  differently  named. 


M.  Lens  (x^^^.  10,  21). — Roimded  or 
discoid  5  surface  in  appearance  tuber- 
cidar.  1-5200"  to  3-5200".  This  spe- 
cies, one  of  the  most  frequent  in  animal 
or  vegetable  infusions,  has  been  recog- 
nized by  most  of  the  ancient  microgra- 
phers.  It  sends  out  obliquely  a  flagel- 
lifomi  filament,  three,  four,  or  even  five 
times  as  long  as  the  body,  and  mobile  in  all 
its  length.  Probably =M.  Guthda(Ehx.). 

M.  concava. — Circular,  concave  on  one 
side,  thin  in  the  centre,  margin  tumid ; 
filament  long,  moveable  throughout.  In 
marsh  water,  Toulouse.     1-2080". 

Isl.  ghhidosa  (x%Tn.  17). — Globular; 
form  mostly  constant;  compressed  at 
origin  of  filament ;  more  globular  than 
M.  Lens,  and  its  sm'face  smooth.  In  sea- 
water  at  Cette,  France.     1-2000". 

M.  elongctta.  —  Elongate ;  nodidar, 
flexible,  of  vaiiable  form.  1-1200". 
In  marsh -water. 

M.  attenuata  (xvni.  19). — Ovoid,  ta- 
pering at  each  extremity,  nodidar,  va- 
cuolse  large  and  distinct,  as  is  also  its 
filament.     1-1660". 

M.  oblonga. — Ovoid,  oblong,  unequal, 
tubercular,  hollowed  by  vacuolae. 
1-3600".     In  veo-etable  infusions. 


M.  nodosa. — Oblong,  irregular,  nodose, 
tapering  behind,  truncate  in  front,  fila- 
ment arising  from  centre  of  truncate  ex- 
ti-emity.  1-2170".  In  sea-water  at 
Cette,  France. 

M.  gihhosa. — Oblong,  angular,  irregu- 
larly distended  and  gibbose ;  filament 
springing  mostly  from  an  anterior  con- 
striction. Length  1-2000".  In  infu- 
sions of  gelatine. 

M.  varians. — Oblong,  narrower  in 
fi'ont,  very  soft,  and  variable  in  form. 
1-650"  tol-700". 

M.  intestinalis. — Yerj  elongated,  form 
constantly  changing,  or  one  end  rounded, 
the  other  tapering  to  terminate  in  a  long 
filament ;  motion  imdulatory.  1-1600". 
Found  in  the  excrement  of  a  newt 
(^Triton  palmipes).  '^I  think  this  is  one 
of  the  species  of  Bodo,  described  by 
Ehrenberg  as  met  vnth.  in  the  intestines 
of  frogs"  (Duj.). 

M.  jiuida., —  Soft,  semifluid;  form 
variable,  iiTegularly  ovoid,  sometimes 
constricted  posteriorly,  hoUowed  by  large 
vacuoles.     1-2600". 

M.  constricta. — Elongated,  four  or  five 
times  longer  than  broad ;  constricted, 
often  much  so  at  the  centre.     1-1300". 


Pertyhas  distinguished  the  following  Monadiform  beings  by  specific  names: — 

rarely  pointed  behind ;  colom-less,  trans- 
parent, with  large  vacuoles ;  filament 
twice  the  length  of  body;  movement 
active  and  revolving.  In  water  contain- 
ing decomposing  Anodonta,  and  foul 
pond-water.     1-1800". 

M.  cordata.  —  Cordate  seen  on  one 
side,  on  another  oval  and  ti'uncate ; 
rounded  anteriorly ;  hyaline  or  greyish 
from  internal  granules  ;  swims  tolerably 
fast  with  an  oscillating  motion,  and  sel- 
dom revolves ;  occurs  singly  and  not 
often;  filament  extremely  difiicult  to 
see,  more  than  double  the  length  of  the 
body.  1140"  to  1080".  In  freshwater 
ponds. 


MoNAS  curvata.  — A  variety  of  3L 
Lens ;  tapering  posteriorly. 

M.  astasioides. — Of  variable  form,  often 
with  one  or  two  longitudinal  lines,  and 
a  central  vacuole.     1-1340". 

M.  irregularis. — more  or  less  globular, 
sometimes  with  capillary  or  angidar  pro- 
cesses; nimierous  dark  internal  mole- 
cules. 1-2000"  to  1-1250".  In  ponds, 
Beme. 

M.  pileatorum.  —  Irregularly  oval  ; 
pointed  anteriorly;  colomiess;  motor  fila- 
ment short,  scarcely  1^  times  the  length 
of  the  body ;  movement  sluggish;  nearly 
resembles  M.  socialis.     1-1400". 

M.  SHccisa. — Oval ;    usually  truncate. 


492 


SYSTEMATIC  HISTOKY  OF  THE  INPUSOEIA. 


M.  urceolaris. — Very  small^  m'ceolate, 
obliquely  emarginate  in  front;  colour- 
less,^ transparent,  with  scarcely  an  ap- 
preciable differentiation  of  substance  ; 
.  filament  indicated  by  the  movement 
produced  in  the  water  at  the  anterior 
extremity;  motion  slow.  1-2640". 
In  brooks  with  Hysgmum  pluvialis. 

M.  excavata. — Round  or  oval,  with  a 
conspicuous  speck  in  the  anterior  half; 
colourless,  or  occupied  with  amorphous 
bro^aiish  or  gi'eenish  matter ;  filaments 
very  fine,  from  2  to  2-^  times  longer 
than  the  body.  Motion  active,  in  a 
straight  line,  and  rarelv  revolving. 
1-2100"  to  1-1200".  At  Berne,  in  ponds 
among  Chara. 

M.  Rotulus.  —  Elongated,  cylindrical, 
of  a  homogeneous   pale-green  colom' ;  I 

Fresenins  has  added  the  foUowing  species  of  Monas  to  the  number  already 
distinguished : — 


filament  apparently  short  ;  onward 
movement  slow,  although  it  revolves 
i-apidly  upon  its  long  axis.  1-3000" 
to  1-600". 

M.  Farcimen.  —  Cylindrical,  greenish, 
with  red  spots ;  flexible  ;  onward  move- 
ment and  rotation  rapid.  1-1800" 
to  1-1080". 

M.  Hilh. — Globular,  or  slightly  elon- 
gate ;  of  a  dusky -green  or  brown  colour. 
Larger  specimens  at  times  present  a 
clear  areola  around  colom-ed  contents, 
with  vacuoles  in  the  latter ;  progression 
tolerably  fast,  turning  more  rapidly  on 
the  long  axis.  Length  from  1-6000"  to 
1-600".  The  three  species  last  named 
approach  very  closely  to  sporozoids  of 
plants. 


Monas  truncata. — Hyaline,  colom*- 
less ;  figm'e  oval  and  rounded,  trmicate 
anteriorly,  compressed;  one  larger  and 
many  smaller  vacuoles  often  seen,  the 
former  near  the  middle.  The  truncate 
end  supports  two  filaments,  mostly  on 
one  side,  equal  to  or  rather  longer  than 
the  body.  Close  beneath  the  anterior 
margin  a  small  transverse  coi-puscle  is 
mostly  visible,  of  a  faint  green  hue,  and, 
some  way  beneath  this,  a  small  contractile 
vesicle.  A  side  view  shows  a  slight 
hollow  on  the  under  surface.  Swims 
without  revolving,  and  mostly  in  a 
straight  course.  1-150  to  1-100  millim. 
in  diam. 

M.  consociata. — Ovate,  with  one  end 
tapering  and  trunk-like,  and  tenninated 
by  a  filament  more  than  double  the 
length  of  the  body.  The  proximal  half 
of  this  filament  often  seems  rigid,  and 
only  the  distal  or  terminal  half,  which 
is  difficult  to  detect  without  the  use  of 
iodine,  motile.  Body  and  its  corpuscles 
colom-less ;  among  the  latter  is  one  pro- 
minent vacuole,  not  contractile.  A  mul- 
titude of  these  Monads  occupied  a  trans- 
parent mucoid  matter,  which  was  not 


seen  in  motion.  In  still  spring-water  at 
Walldorf  in  Jime  and  July.  It  bears  the 
nearest  i-esemblance  to  Cercomonas  vorti- 
cellaris  (Perty).     1-100  to  1-75  millim. 

M.  Oherhauserii. — A  carmine-coloured 
Monad  found  in  the  sulphureous  spring 
at  Frankfort,  allied  to  3fonas  Okenii 
(Elir.),  and  possibly  the  same  as  Chro- 
matmm  Weissii  (Perty).  Cylindrical, 
rounded  at  each  end,  hyaline ;  faintly 
carmine-coloiu-ed,  with  a  variable  nmu- 
ber  of  intensely  crimson  globules  inter- 
nally. Some  specimens,  however,  have 
only  a  homogeneous  red  colom*.  Trans- 
verse fission  frequently  seen.  It  rotates 
rapidly,  and  advances  with  a  tumbling 
sort  of  movement,  no  doubt  by  means  of 
a  filament ;  but  this  eludes  observation. 
1-83  to  1-46  miUimetre. 

M.  hipunctata.  —  A  much  smaller 
species  was  found  in  the  same  glass  with 
the  preceding,  having  a  red  colom*,  an 
elongated  oval  figm^e,  and  a  red  point 
at  each  end.  Longer  specimens  were 
noticed  with  fom'  such  red  points,  which 
might  be  in  the  act  of  fission.  This 
fonn  may  be  the  same  as  the  Monas 
rosea  of  Mon-en. 


Genus  UYELLA  (XYIII.  3,  4). — WeU  characterized  by  the  aggregating 
together  occasionally  of  the  individual  Monads,  so  as  to  foiTu  a  grape-  or 
mulberry-like  mass,  and  by  their  generally  possessing  two  (?)  hair-like  fila- 
ments at  the  mouth.  Like  the  Monads,  says  Ehrenberg,  they  are  deficient  of 
the  projecting  lips,  visual  organ,  and  tail,  and  have  the  mouth  situated  at  the 
anterior  extremity.  They  progress  also  in  the  direction  of  the  longer  axis  of 
theu'  body,  and  are  capable  of  complete  self- division.  Of  the  several  species, 
three  are  green,  and  the  remainder  colourless. 

This  genus  belongs  to  the  Aggregate  Monadina  of  Dujardin,  and  is  thus 


OF  THE  MONADINA. 


493 


defined  by  him  : — "  animals  globular  or  ovoid,  having  a  single  flagelliform  fila- 
ment, and  living  aggregated  in  spherical  masses,  freely  moving  about  in  the 
liquid."  He  ftu'ther  observes  that  isolated  individuals  are  not  at  all  distinguish- 
able from  simple  Monads,  that  there  is  no  good  reason  to  suppose  them  to  live 
alternately  isolated  and  in  masses — a  circumstance  therefore  which  cannot, 
according  to  Ehrenberg's  statement,  be  employed  to  distinguish  them  from 
Polytoma. 

Busk  describes  an  early  stage  of  development  of  Volvocc  Splicer osir a  as 
constituting  *'  a  species  of  the  genus  Uvella,  or  of  Syncrypta,  Ehrenberg  " 
{M,  T.  vol.  i.  p.  40).  Again,  Cohn  (on  Protococcus,  Bay  Soc.  1853,  p.  559) 
makes  one  of  the  multiform  phases  of  development  of  Protococcus  pluvialis, 
"  when  the  zoospore  is  divided  into  thirty- two  segments,"  equivalent  to  a 
Uvella  or  Syncrypta. 

Perty,  in  his  account  of  Uvella  virescens,  denies  the  existence  of  a  common 
envelope,  stating  that  when  the  water  evaporates  from  around  a  specimen, 
the  coveiings  of  each  individual  corpuscle  coalesce,  and  give  rise  to  the  appear- 
ance of  a  general  investment  around  them.  He  adds,  moreover,  that  at 
times  the  corpuscles  are  green,  with  a  clear  central  stripe ;  at  others,  hyaline 
with  a  distinct  green  border,  and  some  scattered  specks ;  and  at  others,  again, 
hyaline  throughout. 

Dujardin  describes  only  two  species,  viz.  U.  virescens,  and  U.  rosacea  =  U. 
Glaucoma  (Ehr.).     Perty  contributes  to  the  list  U.  stigmalica. 


U^^LLA  virescens  (Volvox  Ulva,  M.). 
— Ovate,  coloiu:  green,  occurs  in  dense 
clusters  amongst  Confervas  and  Lemnse. 
1-2000";  diam.  of  cluster  1-280." 

U.  Chamcemorurn. — Smaller  than  the 
preceding  one.  In  water-butts. 
1-2880";  diam.  of  cluster  1-570". 

U.  Uva. — Has  indistinct  vesicles,  and 
is  very  small.  In  stagnant  water. 
1-4800";  diam.  of  cluster  1-960". 

U.  atomus  (3Ionas  atomus,  M.  Lens  et 
Volvox  socialis,  M.). — Voracious,  with 
large  vesicles.  1-6900"  to  1-3406"; 
diam.  of  cluster  1-1150". 

U.  Glaucoma  (Volvox  socialis,  M.). — 
Oval,  inclining  to  conical ;  as  it  advances 
in  age  the  posterior  extremity  is  attenu- 
ated, and  an  elongated  outline  is  assumed. 
Hyaline,  with  large  vesicles,  and  two 
evident  filaments :  individuals  loosely 
aggTegated.  In  1831,  Ehrenberg  first 
observed  a  vibration  at  its  anterior  part, 
and  its  reception  of  coloured  food.  In 
1835,  he  discovered  ^vithin  the  body  of 
this  minute  creature  some  g-reen  Monads 


which  it  had  swallowed.  When  fed  on 
indigo,  as  many  as  twelve  vesicles  were 
filled,  and  it  was  sometimes  seen  to  void 
little  blue  particles,  like  imdigested 
matter,  from  its  mouth.  With  a  power 
of  800  diameters,  a  great  number  of  small 
colourless  gi-anules,  which  he  called  ova, 
were  discerned  lying  between  the  nutri- 
tive sacs.  Fission  both  ti-ansverse  and 
longitudinal  (xviir.  3,  4  :  figm'es  mag- 
nified about  350  diameters).  In  water- 
butts.  1-2300"  to  1-2350";  diam.  of 
cluster  1-430". 

U.  Bodo. — Eounded  in  front,  attenu- 
ated posteriorly;  colour  a  beautiful 
gi'een.  In  stagnant  water.  1-4030"  to 
1-3450";  diam.  of  cluster  1-2350". 

U.  stigmalica  (Perty). — Coi-puscles  of 
a  imiform  sea-green  colom* ;  each  with 
a  very  fine  red  stigma.  They  are  also, 
somewhat  broader  than  those  of  U. 
virescens,  and  have  a  more  decidedly 
hyaline  and  apparently  crenidated  enve- 
lope. At  Berne  much  rarer  than  U. 
virescens. 


Genus  MICPtOGLENA  (XYIII.  6).— Characterized  by  the  presence  of  a 
minute  red  eye-like  speck  at  the  anterior  part  of  the  body.  In  other  respects 
the  species  resemble  true  Monads,  ha\dng  a  very  delicate  filament,  no  pro- 
jecting Hps  and  tail,  and  swim  in  the  direction  of  the  long  axis  of  the  body. 
They  multiply  by  complete  self- division.  Two  species  only  are  known — the 
one  yellow,  and  the  other  green. 

MiCROGLENA  punctifera  (Unchelys  Eye-speck  red  with  a  blackish  central 
punctifera,  M.). — Yellowish,  oval,  or  al-  spot.  Among  slimy- water  plants.  1-620". 
most  conical ;  posterior  extremity  acute.         M.  monadina. — Of  a  beautiful  green  : 


494 


SYSTEMATIC  BISTORT  OF  THE  INFUSORIA. 


form  ovate,  rounded  equally  at  both  ex- 
tremities ;  red  stigma ;  filament  distinct, 
nearly  as  long  as  its  body  j  motion  vibrat- 
ing, rotary  on  its  long  axis,  (xviii.  6. 
Three  animalcules  magnified,  the  first 


800  diameters,  exhibiting  the  internal 
organization  as  represented  by  Ehren- 
berg.)  Among  slimy- water  plants 
(Hampstead  and  Finchley).  1-2300" 
to  1-720". 


Genus  CHLORASTEE. — Solitary,  without  tail ;  mouth  terminal ;  with  a 
frontal  ocellus  or  eye-speck ;  central  portion  of  body  with  radiating  rows  of 
raised  points  (verrucae).  It  is  allied  to  the  genera  Glenomormn  and  Phacelo- 
7nonas,  but  differs  from  the  former  by  being  solitary  (not  clustering),  and  by 
the  greater  number  of  filaments,  and  from  Phacelomonas  by  having  fewer 
filaments. 

Chloraster  gyrans. — Green ;  central  I  acute ;  central  raj^s  of  puncta  four, 
part    of    body    fusiform;    extremities  |  Filaments  from  4  to  5".     1-632". 

Genus  PHACELOMONAS. — Filaments  numerous  (8-10)  around  the  mouth. 
In  other  respects  it  resembles  Microglena :  it  has  the  small  red  eye,  the  trun- 
cated mouth  at  the  anterior  extremity,  but  is  without  a  tail.  It  swims 
in  the  direction  of  the  longitudinal  axis  ;  and  its  self-division  is  simple  and 
complete,  but  not  constant  in  occurrence.  Many  vacuoles  are  seen  within 
the  body,  but  they  have  not  been  noticed  to  admit  coloured  food.  This  genus 
has  not  been  figured  by  Ehrenberg. 


when  dying  it  changes  to  a  globular 
shape.  In  swimming,  it  turns  quickly 
upon  its  longitudinal  axis,  without  any 
vibration.  In  green  puddles.  1-1152". 
Ph.  Bodo  (Stein)  =  Uvella  Bodo  (E.). 


Phacelomonas  Pulvisculus  (Monas 
pidvisculus,  M.). — Figm'e  oblong  or 
slightly  conical,  attenuated  posteriorly ; 
of  a  beautiful  green  coloiu*.  Just  pre- 
vious to  self-division,  its  body  becomes 
cylindrical,  then  contracts  at  the  centre ; 

Genus  GLENOMOEUM  (XYIII.  7).— Characterized  by  having  a  single 
red  eye-speck,  a  truncated  mouth,  and  two  filaments ;  tail  absent.  Self- 
division  simple  and  complete ;  their  clustering  is  voluntary  as  occasion  may 
require,  and  gives  them  the  resemblance  to  a  bunch  of  grapes.  They  STivim 
in  the  direction  of  their  long  axis. 

In  this  enumeration  of  the  characters  belonging  to  this  genus,  we  are  pre- 
sented with  an  excellent  illustration  of  the  table  (and  one  that  exceedingly 
well  explains  its  nse),  under  which  aU  the  genera  of  the  family  Monadina  are 
so  arranged  as  to  exemplify  in  what  respects  they  are  alike,  and  in  what  they 
differ  from  each  other.  For  example  (see  Table,  p.  487),  Glenomormn 
closely  resembles  Uvella,  but  differs  from  it  by  the  superaddition  of  the  red 
stigma  ;  it  differs  from  Monas  and  Mic7vglena  in  occasionally  aggregating ; 
from  Chilomonas,  in  being  deficient  of  the  projecting  lips  ;  from  Bodo,  in  not 
having  the  tail ;  from  Phacelomonas,  by  the  double  proboscis ;  from  Doocococcus, 
by  swimming  instead  of  rolling  over  or  revolving  in  the  water;  and  from 
Polytoma,  by  never  appearing  in  clusters  whilst  undergoing  self-division. 


Glenomorum  tingens  (xviii.  7).  — 
Fusiform,  three  or  four  times  longer  than 
broad,  of  a  beautiful  green  colour,  with 
double,  exceedingly  delicate  proboscis 
about  half  the  length  of  its  body.  Inter- 
nally are  some  small  whitish  vesicles, 
and  the  minute  granules  which  give  rise 
to  the  green  colour.  About  the  centre 
of  the  body  is  a  large  transparent  colour- 
less organ,  the  nucleus.  The  beautiful 
red  eye-speck  is  placed  about  one-third 


from  the  anterior  extremity  of  the  body. 
These  animalcules  constitute  a  great 
portion  of  the  green  matter  commonly 
seen  on  stagnant  water,  and  discovered 
by  Priestley.  They  appear  to  be  nearly 
allied  to  Cercaria  viridis,  from  which 
they  differ  only  in  magnitude  and  in 
the  unalterable  form  of  their  bodies. 
Plentiful  at  Hampstead.  Size  1-3600" 
to  1-1700". 


OF  THE  MONADINA. 


495 


Genus  DOXOCOCCUS.— The  Monads  forming  this  genus  differ  from  all 
others  of  the  family  Monadina  by  the  singularity  of  their  motion,  which  may 
be  defined  to  be  neither  that  of  swimming  nor  of  rotation,  but  a  sort  of  roll- 
ing over  and  over.  In  other  particulars  they  are  like  other  Monads  :  they 
have  the  same  unvarying  form,  and  are  destitute  of  the  eye-speck,  project- 
ing Ups,  and  tail ;  and  self-division  is  simple  and  complete.  Four  species  are 
known. 


Doxbcoccus  Globulus.  —  Subglobose 
or  ovate ;  transparent  as  water ;  easily 
Imown  by  its  tedious  rolling  motion  j 
mouth  not  discerned.  In  salt  water. 
1-860". 

D.  7'uber  (xvin.  8). — Brick-red,  glo- 
bular, and  opaque.  Elirenberg  appears 
to  doubt  whether  this  animalcule  be- 
longs here  (though  its  motion  is  very 
peculiar)  or  to  the  genus  Trachelomo- 


nas ;  and  he  has  not  been  able  to  satisfy 
himself  of  the  existence  of  a  lorica. 
Amongst  Conferv^se,  &c.     1-1720". 

D.  Pulvismliis. — Green,  perfectly  (?) 
globular,  and  opaque.  Amongst  Con- 
fervas.    Not  exceeding  1-1280". 

D.  inequalis.  —  Irregularly  globular, 
transparent,  and  covered  with  green 
spots.     Amongst  Confervae.     1-2400". 


Genus  CHILOMONAS  (XYIII.  14,  18).— Characterized  by  the  obHquity 
of  the  mouth  with  respect  to  the  longitudinal  axis  of  the  body,  which  occasions 
a  projection  above  the  mouth  of  a  lip-like  appearance.  Motion  in  the  dii'ection 
of  the  long  axis  of  the  body ;  form  invariable  ;  devoid  both  of  eye-speck  and 
tail.  Whether  the  projecting  hp  is  furnished  with  cilia,  or  with  a  double 
filament,  Ehrenberg  has  not  satisfactorily  determined,  except  in  the  case  of 
C.  Paramecium,  in  which  he  states  two  filaments  are  to  be  clearly  seen.  On 
C.  destruens  there  are  a  number  of  indistinct  cilia.  Self- division  is  simple  and 
complete. 

Dujardin's  characters  of  this  genus  are,  "Animals  with  an  ovoid,  oblong 
body,  obhquely  notched  in  front,  with  a  very  slender  filament  proceeding  from 
the  bottom  of  the  notch.  Movement  from  before  backwards,  on  its  centre. 
It  is  with  doubt  that  I  refer  the  Infusoria  I  thus  name  to  the  genus  Chilo- 
monas  of  Ehrenberg.  The  mode  of  insertion  of  the  filament  behind  a  pro- 
jecting lip-like  portion,  approaches  the  animals  to  the  Euglence  and  to  certain 
Thecamonadina ;  but  I  cannot  discover  any  trace  of  an  integument,  either 
contractile  or  resistant." 


Chtlomonas  Volvox. — Ovate,  attenu- 
ated and  trimcated  anteriorly,  trans- 
parent and  coloiu-less  ;  projecting  lip 
long ;  wiU  feed  on  indigo.  In  stagnant 
water.    1-1440". 

C.  Parmnechwi  (xviii.  14). — Oblong 
or  ovate,  wider  at  one  end  than  at  the 
other,  keeled  longitudinally ;  colom*  like 
that  of  dirty  water.  The  contained  gra- 
nules have  the  reaction  of  starch.  At  the 
posterior  end  a  clear  nucleus  with  a  red- 
dish halo  may  be  observed ;  and  at  the 
anterior  is  areddish  vesicle,  probably  con- 
tractile. It  refuses  colom-ed  food.  This 
animalcule  is  easily  distinguished  by  its 
shape  and  peculiar  lip-like  process.  With 
a  power  of  about  240,  numerous  vesicles 
are  visible,  and  with  380  the  two  fila- 
ments, which  are  half  the  length  of  the 
body,  and  proceed  from  a  sinus  in  the 
wider  end.  It  moves  in  the  direction  of 
its  long  axis,  in  a  fluctuating  or  waver- 


ing manner.  It  sometimes  clusters.  In 
water  wherein  wheaten  bread  has  been 
steeped.  1-1020".  The  coloiu-less  va- 
riety of  this  species  is  enumerated  by 
Perty  as  one  of  the  many  fonns  of  his 
Cryptomonas  polymorpha. 

C.  destruens. — Oblong,  but  variable  in 
form,  on  accoimt  of  its  softness,  nearly 
colourless  or  faint  yellow.  In  salt  and 
fresh  water,  and  in  the  bodies  of  dead 
Rotatoria,  e.  g.  Anurcea  foUacea  and 
Monocerca  Rattus.     1-860". 

C.  granulosa  (Duj.)  (x\t:ii.  18). — Co- 
lourless, oblong,  larger  anteriorly,  al- 
most invariable  in  form,  although  of  ge- 
latinous consistence ;  filled  with  gramdes 
which  seem  to  project  from  its  surface  ; 
filament  very  fine,  arising  from  an  ob- 
lique notch.     1-940"  to  1-850". 

C.  obliqua. — Ovoid  or  pyriform,  no- 
dular, of  variable  form ;  the  filament  la- 
teral.    1-2600". 


496  SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 

Genus  BODO  (XVIII.  9). — The  caudal  appendage  at  the  posterior  extremity 
of  the  animalcules  is  a  decisive  character  of  the  genus  ;  mouth  terminal,  fur- 
nished with  a  (single  ?)  filament ;  self-division  simple  and  complete  ;  eye- 
speck  absent.  They  never  constitute  true  or  perfect  clusters  like  some  of 
the  family  Monadina,  although,  like  Uvella,  they  occasionally  aggregate.  In 
B.  grandis,  several  vacuoles  have  been  observed,  and  (as  also  in  B.  intestinalis) 
a  simple  (perhaps  double  ?)  filament.  B.  cUdymus  has  been  known  to  divide 
transversely. 

This  genus  Bodo  partly  comprehends  the  genera  Hexamita,  AmphimonaSy 
and  Cercomonas  of  Dujardin,  which  are,  with  others,  introduced  as  addenda 
to  this  family  Monadina.  Dr.  Burnett  has  made  the  following  very  correct 
and  just  remarks  on  this  genus  Bodo  and  its  division  into  species : — 

"The  tailed  Monads  or  Bodos  are  found  in  the  intestines  of  the  common  house- 
fly or  in  those  of  the  frog.  Those  from  the  fly,  when  fii^st  seen,  resemble  in  shape 
a  kernel  of  rye,  and  are  about  1- 6000th  of  an  inch  in  breadth,  and  1 -2000th 
in  length.  Attached  to  the  body  is  a  delicate  hair-like  tail,  four  or  five  times 
its  length.  By  the  addition  of  water,  the  body  enlarges  by  endosmosis,  as- 
suming a  perfectly  spherical  shape  after  passing  thi^ough  all  the  intermediate 
ones,  so  that,  when  magnified  by  the  highest  power  of  Spenser's  microscope, 
it  is  nearly  one  inch  in  diameter,  permitting  the  most  thorough  and  satisfac- 
tory study  of  their  structure,  which  I  find,  after  repeated  observations,  has 
no  peculiarities  except  those  belonging  to  cells.  It  is  a  closed  cell  sac,  mth 
a  filiform  caudate  process,  and  capable  of  the  actions  of  cell-membranes,  viz. 
endosmosis  and  exosmosis.  In  the  interior  of  this  sac  are  found  sometimes 
a  few  granules  and  sometimes  a  nucleus. 

"  In  the  Bodos  of  the  frog,  which  are  larger,  I  have  seen  distinctly,  in  some, 
a  nucleus  with  a  nucleolus,  in  others  two  nuclei,  and  in  others  still,  four 
nuclei  of  equal  size,  thus  showing  that  here  the  multiplication  of  cells  takes 
place,  as  elsewhere,  by  segmentation  of  the  nucleus. 

"  Apart  from  these  characteristics,  which  are  insufiicient,  the  fact  that  I 
have  sometimes  met  with  them  in  the  interior  of  epithelial  cells,  would  be 
strongly  presumptive  of  their  cell  origin  from  minute  granules  that  pass 
through  the  cell-waUs.  The  representatives  of  the  genus  Bodo  therefore 
appear  to  be  simple  cells,  each  with  a  filiform  appendage  for  locomotion,  and 
which  locomotion,  therefore,  can  have  no  adaptive  character. 

"  There  are  differences  in  them  as  they  may  be  taken  from  different  locali- 
ties ;  but,  because  these  particles  are  cell.^  capable  of  much  change  by  dilata- 
tion and  contraction,  these  differences  can  never  serve  as  the  basis  of  species, 
which  would  also  be  true  from  the  fact  that,  having  no  individuality  of  their 
own,  there  is  necessarily  no  absence  of  type  characteristics." 

Bono  intestinalis  (xviii.  9). — Almost 
conical,  transparent,  and  colourless ;  tail 
of  equal  length  with  the  body.     Found 


in  several  living  animals,  such  as  fi'ogs 
and  toads.  Amongst  the  watery  mucus 
of  the  alimentary  canal  Ehrenberg  has 
observed  great  numbers  of  these  crea- 
tures, and  remarks  that  the  Cercaria 
Gyrinus  of  MiiUer  (a  different  animal- 
cule) might  pass  as  a  representation  of 
this  species,  and  that  it  was  confounded 
by  its  discoverer  with  Spermatozoa. 
1-1720". 

B.  ranarmn(=  Cercomonas  Ranarum, 
Perty). — Body  turgid,  ventricles  indi- 
stinct.   In  live  frojj's,  with  the  preceding 


species,  and  with  the  Bursaria  ranarum. 
1-1440". 

B.  viridis. — Green,  nearly  globular,; 
tail  very  short.  Amongst  Confervae. 
1-2400".  Perty  believes  this  species  to 
be  merely  the  young  of  Euylena  viridis. 

B.  socialis  {3Ionas  Lens,  M.). — Ovate 
or  subglobose ;  tail  often  longer  than  the 
body ;  transparent  and  colourless.  Clus- 
ters in  a  mulberry  shape.  Single  forms 
are  sometimes  observed  hopping.  Com- 
mon in  stagnant  water.     1-2970". 

B.  vorticellaris  (=  Cercomonas,  Perty). 
—  Body  three  times  as  long  as  it  is 
broad  ;  tail  verv  short.  In  fresh  water. 
1-11200". 


OF  THE  MONADINA. 


497 


B.  diclymm.  —  Generally  constricted 
about  midway,  tail  short.     1-9600". 

B.  saltans. — Very  small ;  body  with 
ample  ventricles ;  tail  short.  This 
creature,  most  probably  from  its  small 
size,  has  been  mistaken  for  Miiller's 
Manas  Termo ;  but  its  brisk  leaping  move- 
ment will  sufficiently  distinguish  it. 
1-1200". 

B.  grandis. — Oblong ;  vesicles  ample  ; 
tail  rigid,  setaceous,  affixed  to  the  abdo- 
men. In  stagnant  water.  1-864". 
Lachmann  states  that  an  animal  which 
was  probably  Bodo  grandis,  but  might 
have  been  an  Astasia,  devoured  Vibrio 
of  two  to  four  times  its  own  length, 
and  in  this  way  acquired  the  most 
extraordinary  forms  j    the   mouth  was 


close  to  the  insertion  of  the  flagellum. 

B.  ostrecB  (Pritchard). — Globular;  the 
anterior  three-fourths  occupied  with  ve- 
sicles, the  rest  hyaline  ;  length  of  tail 
four  times  the  diameter  of  body.  This 
active  creature  was  discovered  in  the 
liquor  of  an  oyster,  swimming  freely 
among  the  ova  (Sept.  1834).  Diam. 
1-2000". 

B.  ?  Mastix  (Ehr.). — Obovate,  turgid, 
smooth;  terminal  seta  flexuose,  acute, 
exceeding  some  two  or  three  times  the 
length  of  the  body.  Length  1-48"'  to 
1-30"',  with  the  filament  1-20"'.  The 
filament  trails  behind  ;  motion  slow,  not 
leaping.  This  is  the  largest  fonn  of  Bodo 
observed  by  Ehrenberg.  Fomid  about 
Sphagnum. 


The  following  genera,  named  and  described  by  Dujardin,  are  introduced 
into  his  family  Monadina  : — 

Genus  CYCLIDIUM  (D.)  (XXVI.  14,  15).— Body  discoid,  compressed,  or 
lamelliform,  scarcely  variable  ;  the  filament  thicker  and  more  rigid  near  the 
base  than  that  of  Manas,  the  free  extremity  only  being  moved. 

This  genus  is  as  yet  but  artificial,  and  indeed  provisional ;  for  true  Monads 
perfectly  developed  may  possess  a  filament  with  a  thicker  base,  and,  again, 
the  constant  outline  of  the  body  may  be  the  consequence  of  the  presence  of 
an  integument — in  which  case  the  animalcules  in  question  vrould  be  referable 
to  the  family  Thecamonadina.     Movement  slow  and  uniform. 

It  is  to  be  regretted  that  Dujardin  uses  this  generic  name,  as  Ehrenbei^ 
previously  employed  it  to  designate  certain  ciliated  animalcules  which  cor- 
respond but  partially  with  those  of  Dujardin.  Indeed  this  naturalist  ob- 
serves that  "  the  genus  CycVidlum  (Ehr.)  contains  Monads  also,  and  very 
probably  some  of  those  to  which  I  have  applied  the  same  '  generic '  name." 


Cycltdium  nodulostim  (Duj.). — 
Flattened,  discoid,  with  rows  of  nodules 
and  vacuoles;  movement  extremely 
slow.  Length  1-5200".  In  water  from 
the  Seine. 

C.  ahscissum  (Duj.)  (xxvi.  15). — 
Membranous,  lamelliform,  truncated 
posteriorly;  filament  rigid;  movement 
slow,  regular.     1-1040". 

C.  crassum  (Duj.). — Oval,  thick,  and 
rounded ;  filament  thickened  at  its  base 
and  rather  sinuous ;  movements  more 
active,  zigzag.  1-1090".  Length  of  fila- 
ment 1-600". 

C.  distortum  (Duj.)  (xxvi.  14)  ( = 
Spiromonas  voluhilis,  Perty). — Oval,  flat. 


nodular,  irregularlv  bent,  with  a  tumid 
border.     1-1800"  to  1-800". 

^'This  species  is  perhaps  only  one  phase 
of  development  of  Monas  Lens ;  it  was 
found  in  Seine  water  kept  during  three 
months.  When  young  it  has  the  form 
of  a  disk,  with  a  tumid  and  nodular 
margin ;  when,  however,  it  has  grown 
larger,  it  becomes  twisted  upon  itself, 
and  its  movements  irregular.  Some  in- 
dividuals offered  a  certain  affinit}-  wath 
the  Trepomonads,  which  favours  the 
opinion  already  advanced,  that  the  ma- 
jority of  the  Monadina  are  but  modifica- 
tions of  one  or  of  several  types." 


Genus  CERCOMONAS  (D.)  (XVIII.  11,  12,  20,  22,  23).— Body  rounded 
or  discoid,  tubercular,  with  a  posterior  variable  process  in  the  form  of  a  tail, 
of  greater  or  less  length  and  fineness. 

The  Cercomonads  differ  from  the  Monads  by  the  posterior  prolongation, 
which  serves,  by  the  adhesion  of  its  extremity,  as  a  point  of  support :  it  occui's 
either  as  a  very  fine  thread  or  contracted  into  a  small  tubercle ;  it  is  some- 
times nearly  as  fine  as  the  anterior  filament,  and  susceptible  of  an  undulatory 

2k 


498 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


motion.     I  have  not  unfrequently  Tvdtnessed  the  transition  of  Monads  to  the 
condition  of  Cercomonads. 

We  may  conclude  that  many  of  the  animalcules  described  in  the  genus 
Bodo  (Ehr.)  are  examples  of  this  genus  {Cercomonas,  Duj.),  although  suffi- 
ciently marked  characters  are  wanting  in  order  to  discover  specific  identity. 


Cercomonas  detracta.  —  Discoid  or 
oblong,  granular,  with  a  thick  tail. 
1-7000"  to  1-2300". 

C.  crassicauda.  —  Elongated^  nodular, 
flexible,  or  variable  in  fonn,  more  or 
less  contracted  posteriorly  into  a  tail. 
1-3400"  to  1-2600". 

C.  viridis. — Ovoid,  oblong,  tubercular, 
green,  prolonged  posteriorly  into  a  tail 
of  varying  tenuity,  or  into  a  rounded 
lobe  or  spathulate  expansion.  1-1500". 
Perty  believes  this  to  be  no  other  than 
an  early  stage  of  development  of  Euglena 
viridis. 

C.  lacryma. — Globular,  imequal,  elon- 
gated posteriorlv  as  a  long  flexuose  tail. 
Length  of  body  1-5200"  to  1-3000" ;  of 
tail  1-2600'';  of  filament  1-750". 

C.  acuminata  (xviii.  20). — Globular  or 
ovoid,  contracted  posteriorly  into  a  short 
tail,  temiinated  bv  a  veiy  fine  filament. 
1-2600"  to  1-1900". 

C.  Globulus  (xyju.  23).  —  Globular, 
with  a  filament  at  each  extremity  double 
its  length,  the  anterior  one  more  actively 


moved.  Length  1-2600".  In  marsh- 
water. 

C.  longicauda  (xvin,  22). — Fusiform, 
flexible,  terminated  posteriorly  by  a  long 
and  very  slender  flexuose  filament. 
1-1800". 

C.  fusiformis. — Dilated  at  centi'e,  con- 
stricted in  front,  and  prolonged  behind 
into  a  long  delicate  tail.  Length  of  body 
1-1900". 

C.  cylindrica.  —  Elongated,  cylindri- 
cal, constricted  posteriorly,  terminated 
by  a  long,  straight,  and  very  thin  tail. 
Length  of  body  1-2600";  of  tail  the  same. 

C.  truncata  (xviii.  12  a,  h).  —  Con- 
tracted posteriorly;  truncate  in  front, 
with  a  filament  springing  from  each  of 
the  trimcated  angles ;  the  posterior 
angle  extended  more  or  less  into  a 
lobe.     1-3000"  to  1-1900". 

C.  lohata  (xvin.  11  a,  b). — Variable  in 
form,  tubercular,  sending  out  a  flageUi- 
form  filament  from  the  end  of  an  ante- 
rior lobe,  and  emitting  also  one  or  two 
other  lobes.    1-3250"  to  2-3250". 


It  is  right  to  mention  that  Dujardin  has  noted  the  occuiTence  of  several  of 
the  above  Cercomonads  in  organic  infusions,  in  conjunction  particularly  with 
Monas  Lens,  and  that  he  inclines  to  the  idea  that  these  differently-named  In- 
fusoria are  merely  diff'erent  conditions  of  the  same  animalcule. 

Perty  adds  the  following  species  : — 


C.  intestinalis. — Has  a  posterior  vi- 
brating filament,  and  probably  an  ante- 
rior one  also.  Internal  molecules  very 
fine ;  body  transparent ;  posterior  fila- 
ment about  three  times  the  length  of  the 
body.  Is  common  in  the  intestine  of  the 
frog,  and  is  in  part  equivalent  to  Bodo 
intestinalis  (E.).     1-3000". 

C.  curvata. — Cylindrical,  curved,  with 
an  anterior  and  a  posterior  filament.  In 
some  specimens  apparently  two  fila- 
ments occurred  in  front.  1-2400".  Very 
active  :  occurs  among  the  ova  of  the 
frog  {Bana  temporaria). 

C.  vorticellaris= Bodo  socialis  and  B. 
voi'ticellaris  (E.). 


C.  Ra7iarum=Bodoranarum  ?  (E.). — 
Colourless,  soft,  more  or  less  conical ; 
tapering  or  roimded  behind,  but  without 
posterior  filament.  In  water  with  Mol- 
lusca,  and  in  the  intestine  of  frogs. 

C.  clavata.  —  Colourless  or  greyish, 
thickened  anteriorly,  tapering  poste- 
riorly, club-shaped  ;  motion  rather 
quick;  periphery  clearer  than  the 
centre.     1-570". 

C.  Falcula. — Colom^less,  ti'ansparent, 
compressed  and  curved  (?),  much 
widened  in  front,  truncate  and  emar- 
ginate ;  posterior  portion  tapering  to 
a  blunt  apex  ;  movements  sluggish. 
1-720". 


Genus  AMPHIMONAS  (Duj.)  (XVIII.  13).— Animals  of  variable,  irre- 
gular form,  having  at  least  two  filaments,  of  which  one  is  either  in  front,  and 
the  other  on  one  side,  owing  to  a  constriction  of  the  body,  or  both  are  lateral, 
and  accompanied  or  not  mth  a  caudiform  prolongation.  The  leaping  move- 
ments of  A.  caudata  are  remarkable,  and  the  variability  in  form  is  charac- 
teristic of  each  species. 


OF  THE  MONADINA. 


499 


Amphimonas  disjKir  (xyiii.  13  a,  b). — 
Oblong,  of  very  variable  form^  one  or  other 
end  constricted,  or  prolonged  laterally 
into  two  filaments.  1-3500"  to  1-2900". 
Movement  active,  jerking. 

A.  Cauda ta. — Of  very  variable    fonn, 
mostly  depressed,  tubercular,  convex  on  | 
one  side,  angular  on  the  other,  ^vith  a 
filament  proceeding  from  the  summit  of 
each  angle,    1-2180"  to  1-1300". 

"  This  species  seems  to  me,"  says  Du- 
jardin,  "to  be  allied  to  the  JBodo  saltans 
of  Ehrenberg.  In  every  example,  I  saw 
two  flagelliform  filaments,  one  from  the 
anterior,  the  other  from  the  lateral  angle ; 
a  caudifomi  prolongation,  obtuse  or  drawn 
out  as^a  third  filament,  often  adhered  to 
the  slide." 


^  A.  brachiata. — Under  this  name  is  in- 
dicated an  animalcule  of  the  family  Mo- 
nadina,  which  Dujardin  only  once  met 
with,  of  an  ovoid  or  pp-iform  shape, 
filled  mth  granules,  and  giving  oft'  from 
its  narrower  anterior  end  a  simple  flexu- 
ose  filament,  too-ether  ^^dth  a  variable 
dilated  lobe  emitting  two  other  fila- 
ments having  an  imdulatory  motion. 
The  animal  progressed  by  leaps,  revolv- 
ing at  the  same  time. 

A.  exilis  (Perty). — Colom*  soft  grey; 
fio-ure  wedge-shaped,  oftentimes  emar- 
ginate  anteriorly;  filaments  two,  twice 
the  length  of  the  body,  colourless ;  mo- 
tion oscillating.     1-2000". 


Genus  TREPOMONAS  (D.)  (XYIII.  16  &  27).— Body  compressed,  thicker 
and  more  rounded  posteriorly ;  its  anterior  extremity  presents  two  thin  lobes, 
bent  to  one  side  and  each  terminated  by  a  flagellifonn  filament,  which  pro- 
duce an  active  whirling  and  jerking  movement. 

"  The  examples  of  this  genus  are  very  common  in  all  collections  of  marsh- 
water  containing  decomposing  plants,  but  are  most  diificult  to  determine, 
owing  to  the  irregularity  of  their  form  and  the  rapidity  of  their  movements, 
I  have  rather  glimpsed  than  certainly  detected  their  flageUiform  filaments, 
and  have  in  vain  attempted  accui^ately  to  delineate  them," 

Trepomonas  agilis  (xviii.  16,  27). — Body  gi'anular,  unequal,     1-1300". 

Genus  HEXAMITA  (D.)  (XXVI.  1).— Animals  with  an  oblong  body 
rounded  in  front,  constricted  and  bifid  or  notched  behind.  Two  to  four  fila- 
ments extend  from  the  anterior  border ;  and  the  two  posterior  lobes  are  pro- 
longed as  two  flexuose  filaments. 

This  genus,  characterized  by  the  number  of  its  motor  filaments,  appears 
sufiiciently  distinct  from  the  preceding.  Its  species  occur  in  decomposing 
marsh-water  and  in  the  intestine  of  Batrachians,  but  not  in  artificial  infu- 
sions. 

Hexaishta  nodidosa  (xx^tc.  1). — Ob- 
long, ^vith  three  or  four  longitudinal 
rows  of  nodules,  the  two  lateral  of  which 
are  extended  into  tapering  slender  lobes, 
each  terminated  by  a  filament;  move- 
ment vacillating.      1-1-300"  to  1-1500". 

H.  itiflata.  —  Oval  oblong,  rendered 
almost  quadrangular  by  the  processes 

Genus  HETEROMITA  (D.)  (XXVI,  5;  XVIII,  26).— Body  globular, 
ovoid,  or  oblong,  with  two  filaments  extending  from  the  same  point  in  front 
—■one  slender,  undulating,  and  producing  an  onward  movement,  the  other 
thicker,  stretching  posteriorly,  and  free,  or  contracting  adhesion  with  the  glass 
sHde  along  which  it  moves,  so  as  to  cause  a  sudden  movement  backwards. 

''  The  several  sections  of  the  Monadina,  together  with  the  Thecamonadina 
and  the  Euglenae,  contain  Infusoria  possessing  two  filaments,  by  one  of  which 
they  progress,  by  the  other  adhere  for  support  to  any  solid  body,  and  produce 
a  sudden  movement  backwards  by  its  contraction.  To  prevent  confounding 
specimens  of  these  several  families,  the  same  distinctions  which  mark  the 

2k2 


which    give    origin    to    the    filaments. 
1-600"  to  1-1300". 

H.  intestinaUs. — Fusiform,  prolonged 
into  a  bifid  tail.  Very  common  in  the 
abdominal  cavity  of  the  Batrachia  (frogs 
and  newts).  It  moves  in  a  straight  line, 
oscillating  from  side  to  side. 


500 


SYSTEMATIC  HISTOEY  OF  THE  INFXJSOKIA. 


Monadina  generally,  must  be  found  in  order  to  constitute  the  Heteromita 
members  of  that  family, — such  as  the  absence  of  integument,  the  gelatinous 
appearance  of  the  entire  mass  admitting  of  agglutination  to  other  objects, 
and  the  drawing  out  of  its  substance  into  filamentous  processes,  together  with 
the  existence  of  certain  corpuscles,  which  can  only  have  penetrated  the  inte- 
rior as  a  consequence  of  the  formation  of  vacuoles  at  the  surface  "  (Dnj.). 


Heteromita  ovata  (xxvi.  6).  — 
Ovate,  narrower  anteriorly,  containing 
vacuoles,  granules,  and  Naviculse. 
1-1050"  to  1-1150". 

This  is  probably  the  Bodo  granclis  of 
Ehrenberg.  His  other  Bodos  are  not 
HeteromitcB,  but  imperfectly-observed 
Cercomonads  or  Amphimonads. 

H.  Gramdum. — Globular,  surface  gra- 
nular. 1-2600".  In  rather  putrid  sea- 
water. 


H.  angusta.  —  Narrow,  lanceolate, 
slightly  bent,  tapering  at  each  end,  with 
a  flag'elliform  and  a  second  filament  from 
the  same  point  anteriorly,  erect  at  the 
base,  but  floating  freel}^  the  rest  of  its 
length.     1-1050". 

This  is  a  doubtful  species ;  it  is  of  the 
shape  of  a  lanceolate  leaf,  wUh.  a  mid- 
rib or  longitudinal  fold. 


The  following  species  are  from  Perty's  work  :- 


H.  pusitla. — ^^Colourless,  very  delicate, 
cylindrical  or  Euglena-like  in  figm-e, 
constricted  at  the  centre,  often  eniargi- 
nate  posteriorly ;  filaments  2  to  2^  times 
longer  than  the  body ;  movements  in- 
active, oscillating ;  few  fine  gTanules  in- 
ternally. 1-3000"  to  1-2160".  AlHed 
to,  but  smaller  than,  H.  migusta,  and 


like  Amphimonas  dispar,  in  which,  how- 
ever, both  filaments  are  equal.  In  ponds 
at  Thun. 

H.  exigua. — Oval  or  spheroidal,  co- 
lourless ;  filaments  about  three  times 
the  leng-th  of  the  bodv  ;  movements  in- 
active. 1-7000"  to  1-4800".  In  turf- 
hollows  on  the  Bernese  Alps. 

Genus  TEICHOMONAS  (D.)  (XVIII.  28).— Body  ovoid  or  globular,  capable 
of  being  drawn  out  when  adherent,  and  in  this  way  presenting  sometimes  a 
caudal  prolongation.  The  anterior  flageUiform  filament  is  accompanied  with 
a  group  of  vibratile  cilia. 


turning  on  its  axis.    1-1730".    Found  in 
the  intestine  of  Limax  agrestis. 

T.  Batrachiormn  (Perty)  (x\Tni.  28  a,  6, 
c,  d).  —  Widely  oval,  at  times  slightly 
emarginate  in  front,  mostly  with  a  keel 
along  the  back,  colourless,  and  8  to  10 
cilia  on  the  left  side;  resembles  T. 
Liimicis,  but  is  more  finely  granidar. 
1-2400"  to  1-1300". 


Trichomonas  vaginalis. — Gelatinous, 
nodular,  unequal,  hollowed  by  vacuoles, 
often  adhering  to  other  bodies ;  nwve- 
mcnt  oscillating.     1-2600". 

T.  Limacis. — Ovoid,  smooth,  pointed 
at  each  end,  and  terminating  in  front  by 
a  flageUiform  filament,  from  the  base  of 
which  a  row  of  vibratile  cilia  is  directed 
backwards ;  progressive  movement  act- 
ive, the   animalcule  at  the  same  time  ] 

Genus  ANTHOPHYSA  (D.)  (XXYI.  2). —Animals  ovoid  or  pyriform, 
furnished  with  a  single  flageUiform  filament,  and  collected  in  clusters  at  the 
extremities  of  a  branching  stem,  or  polypidom,  secreted  by  themselves;  clusters 
when  detached  resembling  those  of  Uvella. 

The  tree-like  polypary  is  brown  at  the  base,  but  clearer  and  even  dia- 
phanous at  the  termination  of  the  branches,  which  appear  nodular.  The 
groups  of  animalcules  are  easily  detached  from  the  stem,  and  then  commence 
a  rotatory  movement  by  the  action  of  the  filaments  of  each  individual  in  the 
group.  Detached  solitary  animalcules  move  like  the  common  monads  with  a 
single  filament.  The  branching  support,  at  first  soft  and  gelatinous,  becomes 
by  degrees  more  consistent,  brown,  and  of  a  horny  character,  appearing  to 
partake  no  longer  of  the  vitality  of  the  animalcules. 

A.  Mulleri  Avas  erroneously  placed  by  Ehrenberg  in  the  genus  Epistylis, 
among  the  YorticelUna,  and  called  E.  vegetans. 

The  delicate  branched  fibre  or  stem  has  been  considered  a  microscopic 


OF  THE  irONADnfA. 


501 


fiingus,  and  been  named  by  Kiitzing  Stereonenm.  Upon  this  view,  the 
monadiform  beings  crowning  the  summits  of  the  branches  have  been  con- 
ceived to  represent  the  spores.  This  opinion  has  been  carefully  investigated 
and  rejected  by  Cohn  (Entwich.  d.  ynilcroskop.  Algen  u.  Pilze,  pp.  11-J— 115), 
who  confirms  Dujardin's  description,  and  regards  it  as  a  stalked  Uvella. 


Anthophysa  Mulleri.  —  With  the 
characters  descril«d. 

A.  soUtaria  (Borv'). — A  species  was 
described  under thisname by Bory  de St. 
Vincent,  and  is  again  brought  to  notice 
by  Fresenius,  who  met  with  it  in  some 
standing  water  -wath  Salvinia.  The 
stem  is  simple  (not  branched),  and  has 
a  clear  outline  to  its  extremity.  Its 
length  is  from  1-25  to  1-8  millim. ;  and 
in  water  it  has  a  clear  brownish-green 
colom'.    Its  apex  is  surmounted  by  the 


monadiform  beings,  looking  like  so  many 
short  hyaline  fibres.  Each  monad  con- 
tains a  comparatively  large  non-con- 
tractile vacuole  having  a  red  refraction, 
and  is  furnished  with  a  filament  at  its 
free  extremity.  Length  of  monads 
1-100  to  1-75  millim.  The  fixed  stem 
can  bend  itself  from  side  to  side.  In 
one  specimen  a  contractile  vesicle  was 
seen  in  one  of  the  monads.  This  organism 
appears  to  be  precisely  the  same  as  the 
Epistylis  Botrytis  (Ehr.), 


Genus  PEBOMUM  (Cohn),  represented  by  one  species. 


Peronium  aciculare  has  been  newly 
described  by  Cohn  (JEntwick.  &c.  p.  158) 
as  a  form  aUied  to  Anthophysa.  It  is 
parasitic  on  the  spores  of  JPihtlaria,  and 


consists  of  a  delicate  colomless  fibre  sur- 
mounted by  a  globular  head,  which  re- 
solves itself  into  numerous  swarm-ceUs 
of  a  monadifonn  character. 


The  two  next  genera  are  named  by  Werneck  {Monatshericht  der  Berlin. 
Ahad.  1841,  p.  377),  and  thus  briefly  described  : — 

Genus  ANCYRIUM  =  Enterodelous  Bodos  {i.e.,  according  to  the  nomen- 
clature of  Ehrenberg,  Bodos  furnished  with  an  intestinal  tube)  with  a 
moveable  setaceous  foot. 

The  existence  of  an  alimentary  tube  (so  supposed)  removes  the  Bo  do 
gi'andis  and  the  six  allied  species  (^.  e.  the  genus  Ancyrium)  far  above  the 
Monadina  of  Ehrenberg,  whilst  the  possession  of  the  setaceous  foot  also  indi- 
cates a  higher  organization. 

Genus  EBETES  =  Loricated  Phacelomonads. 

The  following  are  the  new  genera  of  Monadina  instituted  by  Perty : — 
Genus  TETBAMITUS  (Perty)  (XIX.  3).— Figui-e  conical,  tapering  pos- 
teriorly, and  having  four  vibratory  filaments  in  front.     He.vamita  differs  in 
having  in  addition  two  posterior  filaments. 

Tetramitus  descissus  (xix.  3). — 
Wedge-shaped,  curved,  truncate  ante- 
riorly, and  colom-less  or  pale  gi'ey.  Sur- 
face marked  bv  cross-lines.     Movements 


prominent  angle  or  beak.  Smallest 
specimens  1-7000",  the  largest  1-1080" 
in  length.  Bern.  In  stale  pond-water. 
Fresenius  describes  it  as  rather  pp-ifonn, 
trimcate  anteriorly,  with  a  short  trunk- 
like  process  from  one  side ;  elongated  and 
pointed  behind.  A  vesicle  (contractile  ?) 
at  the  anterior  extremity. 


tolerably  active  and  oscillating.  Fila- 
ments nearlv  twice  the  length  of  the 
body.     1-1860". 

T.  rostratus. — Colourless,  with  an  an- 
terior border  j  one  side  elongated  as  a 

Genus  MALLOMOI^AS  (Perty)  (XIX.  4-6).— Body  oval,  eUiptic,  or  discoid, 
with  brown  or  greenish  contents.  Surface  covered  with  long  motionless 
hairs.     A  single  filament  anteriorly,  double  the  length  of  the  body. 

of  the  hairs ;  these  are  commonly 
longer  on  the  posterior  half.  Contents 
sometimes  seen  longitudinally  or  trans- 
versely divided.  Movements  rather 
rapid,  but  rarely  attended  by  a  rotation 
of  the  body.     In  one  example  the  hairs 


Mallomonas  Plosslu  (xix.  4-6) 
(formerly  described  as  3f.  acaroides). — 
Mostly  oval ;  the  smaller  end  anterior ; 
rarely  elliptic  or  discoid ;  the  periphery 
apparently  crenulated — an  appearance 
probably  due  to  the  points  of  insertion 


502 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


seemed  terminated  by  a  knob.  It  is  not 
improbable  that  Fantotrichum  Enchelys 
(E.)  is  also  a  member  of  this  genus. 
1-1440"  to  1-960".  Bern.  In  ponds. 
—  A  variety  (3/.  epilis)  occurs,  hav- 
ing the  hairs  short  or  actually  absent, 
although  covered  with  little  nodules 
which  serve  as  bases  for  hairs.  Frese- 
nius  has  noticed  this  organism.-  He 
adds,  the  ends  are  often  pointed.  The 
hairs  or  bristles  are  long,  and  tolerably 
numerous — as  many  as  30  have  been 
counted,  placed  at  all  parts  of  the  peri- 
phery. The  anterior  setiform  hairs  are 
most  concerned    in  locomotion  j  those 


placed  laterally  either  lie  along  the  sides 
pretty  closely,  or  stand  out  at  a  greater 
or  less  distance,  and  appear  concerned 
chiefly  in  changing  the  position.  The 
two  most  in  advance  seem  to  have  the 
character  of  feelers.  A  clear  vacuole 
was  sometimes  seen  in  the  middle  of  the 
dusky-green  contents.  A  few  small, 
contractile,  optically  red  specks  have 
also  been  observed.  1-720"'  to  1-444"'. 
Fresenius  considers  it  ought  to  be  re- 
moved from  the  Monadina;  and  Perty 
is  himself  imable  to  decide  whether  this 
genus  is  referable  to  the  Ciliata  or  to  the 
Phytozoa. 


Genus  PLEUROMONAS  (Perty)  (XYIII.  25).— Body  reniform,  extremely 
delicate,  small,  colourless;  filament  extended  from  the  concave  side  of  the 
body,  and  three  times  its  length. 


Pleuromonas  jaculam  =  Chilomonas 
ohliqua  (?)  (Duj.)  (x^mi.  25).— Colour- 
less, transparent,  with  a  few  small  mole- 
cules. Movements  eccentric,  hither 
and   thither   in   a  jerking  and  leaping 


manner,  followed  by  inter^^als  of  rest. 
Very  young  specimens  are  round. 
1-6000"  to  1-3160".  Bern.  In  stale 
water  and  infusions  of  Lycopodium 
seeds. 


Genus  SPIPOMONAS  (Perty)  (XVIII.  24).— Body  leaf-like,  compressed, 
rounded  at  both  ends,  and  roUed  spirally  on  itself  longitudinally. 


Spiromonas  voluhilis  =  Cyclidium  dis- 
tortum  (Duj.). — Colourless,  transparent, 
smooth,  very  delicate.  Revolves  rapidly 
on  its  long  axis.  Not  nodular  on  the 
margin,    like    the    CycUdium   distortimi 


of  Dujardin,  but  is  probably  (as  Dujar- 
din  believes  the  latter  to  be)  merely  a 
phase  of  3Ionas  Lois.  1-1800"  to 
1-1300".     Bern.     In  foul  water. 


Genus  MENOIDIUM  (Perty)  (XIX.  2).— Body  small,  crescentic,  thicker 
on  the  outer  or  convex  margin ;  containing  internally  smaU.  molecules  and 
vesicles ;  colourless,  or  occupied  with  a  little  chlorophyll. 

Menoidium    pellucidum   (xix.    2).  —  j  sickle.    Movement  tolerably  rapid,  jerk- 
Eecalls  by  its  figure  a  little   Closteriimi  I  ing  and  revolving.     1-670"  to  1-430". 
lunula ',  not  rounded,  but  flattened  like  a  { 

Genus  CHROMATIUM  (Perty)  (XIX.  1).— Body  extremely  small,  red, 
brown,  violet,  or  green  in  coloiu-,  containing  in  the  matiu'e  condition  some 
internal  vesicles.  A  motor  filament  at  the  anterior  extremity  (?).  Multipli- 
cation by  transverse  fission.  To  this  genus  Perty  would  refer  the  greater 
part  of  the  Monads  described  by  Ehrenberg  which  possess  a  brilliant  colour ; 
and  he  is  in  doubt  whether  they  are  not  all  rather  referable  to  the  genus 
Bacterium,  as  well  as  the  next  genus  named,  i.  e.  Acariceum.  However,  he 
at  present  retains  Chromatium  and  Acariceum  among  the  Monadina,  and 
establishes  two  species  of  the  former. 


Chromatium  Weissii  (xix.  1).  —  Of 
a  violet  or  bro"v\Tiish  colour,  rounded 
and  truncate  both  before  and  behind; 
vesicles  -wdthin  sharply  defined.  The 
3Ionas  Ohenii  of  Weisse  is  very  closely 
allied,  but  still  more  minute.  It  pro- 
gresses and  revolves  rather  rapidly,  taking 


a  straight  com'se.  The  vesicles  are  not 
present  in  very  yoimg  specimens :  they 
first  show  themselves  as  dark  points,  and 
afterwards  assume  the  vesicular  form. 
Perty  cannot  discover  the  filament  de- 
scribed by  Ehrenberg  in  Ifonas  Okenii. 
Eichwald  says  of  this  species  that  it  swims 


OF  THE  HYDEOMORINA. 


603 


backwards  or  forwards  indifferently, — 
a  circumstance  adverse  to  the  existence 
of  a  filament  at  aU.  1-4800"  to  1-2400". 
Occm-s  among  Characeae. 

C.  violescens. — Globular  or  elliptical, 
transparent,  and  of  a  very  pale  violet 
colour.  It  appears  closely  related  to,  al- 
thoug-li  not  identical  with,  Monas  vinosa 
(E.).  A  filament  could  not  be  detected, 
nor  anv  internal  organs.     At  Bern,  with 


Chara.  1-14,000"  to  1-3000".  These 
coloured  organisms  form  a  colom-ing 
layer  on  the  mud  at  the  bottom  of 
ponds,  kc.  The  several  species  men- 
tioned by  authors  referable  to  the  genus 
Chroinatium  are — 3Ionas  rosea,  Morren  ; 
3Ionas  Okenii,  Weisse  ;  Monas  vinosa,  M. 
eruhescens,  31.  ochracea,  and  probably 
31.  prodigiosa  and  31.  gliscetis  of  Ehren- 
berg's  categorv. 


Gemis  ACAELEUM. — Extremely  minute,  globular  or  elliptical ;  perfectl} 
transparent,  without  a  trace  of  either  external  or  internal  organs. 


AcARi^UM  Crepuscuhim  =  3Ionas  Cre- 
pusculum  (E.).— They  swim  rapidly  past 
each  other,   yet  have  nothing  in  their 


movements  in  common  with  those  of  the 
Monads,  but  much  rather  with  those  of 
the  Bacterium  Termo. 


Genus  RHABDOMONAS  (Fresenius). 


RHABDOMONAS  incurva.  —  Stout, 
elongated  and  cylindi-ical,  slightly  fal- 
cate ;  anterior  extremity  rather  the 
thicker;  three  prominent  longitudinal 
ridges  ;  green  vesicles  or  granules  occupy 
the  anterior  half  of  the  body ;  progresses 


in  a  straight  line,  with  a  rotary  or  semi- 
rotary  motion  on  its  long  axis ;  filament 
li  the  length  of  the  body.  1-60  to 
1-50  millim.  In  stagnant  water  with 
Confervse,  &c. 


Genus  GRYK/EA  (Fresenius). 

Gryivi^a  vacillans. — Colourless,  hya- 
line, compressed;  when  seen  on  its  fiat  side 
its  outline  is  circular,  but  on  the  narrow 
side,  pyriform,  the  posterior  compressed 
portion  gradually  thickening  towards  the 
thicker  front  part.     Advances  with  the 


thick  end  foremost,  slowly  revolving  on 
its  long  axis,  with  an  oscillating  motion. 
Filament  revealed  by  iodine.  In  stand- 
ing water  with  Vallisneria  in  the  Botanic 
Gardens.  It  is,  not  unlikely,  the  same 
being  as  3Ionas  urceolaris  (Perty). 


FAMILY  II.— HYDROMORINA. 

Characters. — Anenterous  Polygastrica  without  appendages  ;  body  uniform, 
like  that  of  the  Monads,  but,  by  reason  of  the  spontaneous  fission  being  im- 
perfect, developed  into  a  moniliform  mass  or  polypary  ;  lorica  absent.  Indi- 
viduals are  at  periods  set  free,  which  commence  the  same  cycle  of  compound 
development  as  the  parent  beings  to  which  they  oi-iginally  belonged  (Ehr.). 

The  genera  belonging  to  this  family  are  Polytoma  and  Spondylomorum. 
Poly  to  ma  was  described  by  Ehrenberg  in  the  family  Monadina ;  but  the  sub- 
sequent discovery  of  the  genus  Sjpondylomoriim,  ha\ing  the  same  general 
characters,  and  differing  like  it  from  the  other  monads,  led  him  to  create  this 
new  family  Hydromorina  to  embrace  the  two. 

Perty  has  also  recognized  the  propriety  of  detaching  those  Monadina  which, 
by  the  act  of  self-fission  continuing  incomplete,  live  together  in  compound 
masses,  and  to  designate  them  has  invented  the  term  "  3Ionadina  Familiaria,^^ 
equivalent  in  EngKsh  to  ''gregarious  or  aggregated  Monadina."  Under  this 
group,  however,  he  has  placed  two  other  genera,  which  Ehrenberg  has  let 
remain,  somewhat  unaccountably,  among  those  Monadina  liWng  in  an  isolated 
or  free  state.  These  other  members  of  the  Hydromorina  or  Aggregated 
Monads  are,  Uvella  and  Anthophysa.  Schneider  {A.  N.  H.  1854,  xiv.  326) 
observes  on  the  near  alliance  of  Polytoma  to  Chlorogonhim  eucJdormn.  It 
would  seem  that  Cohn  fails  to  find  any  truly  distinctive  characters  between 


504 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Polytoma  and  Chlami/domonas ;  for  he  proposes  (EntiuicJc.  p.  140)  to  apply  to 
P.  Uvella  the  name  of  Chi.  hyalina. 

Genus  POLYTOMA  (XVIII.  5  ;  XX.  1-14).— Mouth  terminal,  truncate, 
surmounted  by  a  double  flagelliform  filament  situated  as  in  Monas  and  Uvella ; 
eye  and  tail  wanting.  It  will  not  imbibe  colouring  matter.  A  large  con- 
tractile vesicle  and  the  trace  of  a  nucleus  are  sometimes  observable.  Self- 
di\4sion  occurs  both  transversely  and  longitudinally,  and  produces  a  berry-like 
cluster  of  many  individuals.  As  the  young  increase  in  size,  the  parent  body 
assumes  a  decussated  or  wrinkled  appearance,  like  a  mulbeny,  and  in  this 
manner  indicates  its  approaching  self-division  into  manif  sections  (as  the  name 
Polytoma  denotes),  or  numerous  individuals.  In  swimming,  the  filaments  are 
extended  in  advance.  In  putting  foi^ard  the  self-division  of  Polytoma  as  a 
peculiar  feature,  Cohn  says  that  Ehi-enberg  has  mistaken  a  transitional  for  a 
permanent  condition.     It  was  known  to  Midler  and  Wrisberg. 


Polytoma  Uvella  {Monas  Uva,  M.). 
— Colomless,  of  an  oval  or  obloug  form ; 
extremities  equally  obtuse.  It  is  often 
abundant  in  water  where  animal  matters 
are  in  solution,  upon  which  it  appears  to 
be  nourished ;  generally  in  company  with 
species  of  Vibrio  and  Spirillum^  and  some- 
times with  Uvella  Uva  and  U.  Atomus. 

Group  5  shows  two  isolated  indi- 
viduals ;  another  about  to  divide  longi- 
tudinally; a  cluster  of  eight  imited 
within  a  conmion  envelope ;  another 
cluster,  of  which  the  common  envelope 
has  disappeared  prior  to  the  separation 
of  the  individual  Monads,  and  in  the 
two  isolated  beings  the  double  filament 
is  very  distmct,  1-200"  to  1-90"; 
diam.  of  clusters  1-380". 

Schneider  (Part  I.  p.  136)  has  closely 
examined  this  species  (xx.  1-14).  The 
hyaline  investing  membrane,  he  says, 
can  be  distinctly  displayed  by  using 
chromic  acid,  or  solution  of  iodine  in 
chloride  of  zinc.  A  globidar  nucleus 
lies  near  the  centre,  with  a  narrow  red- 
dish halo  around  it :  dilute  acids  render 


this  more  distinct  (xx.  2).  At  the 
anterior  extremity  are  two  reddish  vesi- 
cles, which  are  contractile ;  and  other 
non-contractile  reddish  ones  are  scattered 
in  the  interior.  The  creature  "  rotates 
upon  its  axis  ;  and  this,  again,  describes 
circular  vibrations  upon  a  central  point." 
Self-division  takes  place  at  first  into  two 
(xx.  3),  then  into  fom'  (xx.  9),  and,  under 
favourable  conditions,  mto  eight  seg- 
ments, each  of  which  acquires  its  fila- 
ments, and  moves  about  within  the  en- 
velope of  the  parent  with  the  rest  imtil 
set  free  by  its  rupture.  Under  certain 
circumstances  the  individuals  pass  to  a 
state  of  rest  (xx.  7),  and  then  do  not 
imdergo  fission  or  any  other  change,  but 
remain  in  a  torpid  condition.  In  assum- 
ing this  state  the  filaments  contract 
gradually,  and  at  length  seem  to  be 
withdra-wn  completely  within  the  con- 
tained substance  of  the  encysted  being. 
The  internal  granules  of  Polytoma  are, 
according  to  Schneider,  composed  of 
starch,  and  are  convertible  into  a  blue 
or  a  green  colouring  matter. 


Party  has  distinguished  three  additional  species,  viz.- 


POLYTOMA 

many  as  ten 


Uva.  —  Divides  into  as 
segments.  The  mode  of 
fission  much  resembles  that  of  Chlamy- 
domonas,  but  differs  in  exhibiting  active 
movements  during  the  process,  instead  of 
the  state  of  rest  seen  in  the  latter.  The 
corpuscles  are  usually  oval,  and  hya- 
line;  rarely  yellow  or  brown ;  filled  "u^th 
larger  or  smaller  vesicles,  and  in  old 
specimens  with  black  molecides.  Self- 
di\ision  proceeds  rapidly.  Movements 
darting  and  revolving.  An  enveloping 
cyst  has  been  noticed  in  some  examples. 
Uncommon  in  fresh,  but  frequent  in 
water  holding  animal  decomposing  mat- 
ters  in    solution.      Two    varieties    are 


distinguishable:  viz. — Var.  a  uni/iliSf 
having  only  one  filament,  resembling 
Trachelim  ghhulifer  (E.),  and  very  pro- 
bably identical  with  Monas  puncfimi; 
Var.  b.  7'ost7'ata  seu  hysginoides,  of  a 
feeble  yeUow  colour,  with  a  prominent 
cyst-wall,  within  which  it  is  contracted 
and  deprived  of  its  filaments.  It  does 
not  break  up  on  drying,  but  can  continue 
several  weeks  without  change.  [This  is 
evidently  not  even  a  variety  in  the  proper 
sense,  but  simply  an  encysted  Polytoma.'] 
P.  ocellata.—OYB\',  filled  with  vesi- 
cles, like  P.  Uva,  except  that  it  has  a 
clear-red  stigma  at  the  centre.  Motion 
languid.     Self-fission  produces  few  new 


OF  THE  CKYPTOMONADDfA. 


505 


beings  5  and  these  lie  pai'allel  to  each 
other.  Has  the  dimensions  of  P.  Uva. 
Found  in  decomposing  infusions. 
Schneider  describes  a  peculiar  mode 
of  fission  seen  at  times  in  P.  TJvella,  in 
which  the  segments  lie  parallel  to  each 
other  :  very  probably  this  supposed  spe- 
cies, P.  oceUatum,  is  nothing  more  than 
that  pha^e  of  P.  Uvella.  The  reddish 
vesicle  is  worthless  as  a  specific  character. 


P.  ?  virem. — Greenish  or  actually  green, 
suiToimded  by  a  hyaline  cyst.  Seen  only 
in  process  of  fission,  when  each  segment 
had  its  own  filament.  These  organisms 
were  for  some  seconds  at  rest,  and  soon 
afterwards  moved  here  and  there  vdt\\ 
activity.  Very  probably  this  being  is 
only  a  sporule,  and  seems  nearly  akin  to 
CJilamydomonas. 


Genus  SPONDYLO^IORUM. — Individuals  furnished  vdih.  a  dorsal  ocellus, 
are  destitute  of  a  tail,  and,  in  consequence  of  their  imperfect  self-division,  deve- 
lope  a  compound  body  (polypaiy)  resembling  a  whorl  or  cluster  of  berries. 

Spoxdylomoeum  quaternarium.  —  A 
gi'oup    of    four  alternating    coi-puscles, 


of  which  the  tenninal  one  is  the  most 


slender ;  colour  green  ;  filaments  four  to 
five.  Length  of  polyparv  1-576",  of  each 
indi^ddual  1-1728". 


FAMILY  III.— CRYPTOMONADINA. 

(XYIII.  29-34 ;  XIX.  7-16  and  20-31 ;  XXVI.  6,  8,  9,  10.) 

The  Cryptomonadina  {vide  General  History,  p.  140)  are  Monadina  enve- 
loped within  a  distinct  gelatinous,  membranous,  or  hard  induvium,  forming  a 
shell-like  covering  or  lorica.  According  to  Ehrenberg,  the  lorica  sometimes 
resembles  an  open  shield  (scutellum),  at  others  a  closed  box  or  pitcher  (urce- 
ohis).  The  constmction  of  the  lorica,  however,  as  a  scutellum,  open  on  one 
side,  is  denied  by  every  recent  writer ;  and  in  all'cases  it  would  appear  to 
completely  enclose  the  contents.  Two  delicate,  filiform,  and  generally  re- 
tractile filaments,  capable  of  being  put  into  very  powerful  whirling  and  lash- 
ing motion,  are  clearly  perceptible  in  all  the  genera,  excepting,  perhaps,  the 
genus  LageneUa ;  and  even  in  this.  Dr.  Wemeck  believed  he  had  discerned 
them.  Six  or  seven  species  exhibit  internal  vesicles ;  and  in  two  genera  a 
coloured  spot  is  present  at  the  fore  part  of  the  body.  Prom  the  position  of 
this  speck  the  dorsal  line  may  be  readily  conceived,  and  a  right  and  left  side 
described.  Self- division,  when  it  occurs,  is  simple  and  complete.  "  It  is 
possible,"  says  Ehrenberg,  "  that  the  fossil  animalcules  discovered  in  the  flint 
of  chalk  and  porphyiitic  formations,  and  named  by  me  Pyx'idicida  (see  Plate 
XYII.  upper  figui-es),  belong  to  the  genus  Trachelomonas.^^ 

Lachmann  (oj).  cit.  p.  219)  asserts  that  in  all  transparent  Monadina  and 
Cryptomonadina  a  contractile  vesicle  exists,  and  that  even  in  the  more  opake 
ChUomonas  Paramecium  and  Cryptomonas  ovata  he  was  able  to  observe  its 
contractions.     Mr.  Carter  confiims  this  statement. 

The  genera  were  thus  tabulated  by  Ehrenberg  : — 


Eye-speck 
absent. 


Eye-speck 
present. 


(  f  Form  short ;    self-division  1  r\ t. 

Lorica  obtuse  and  smooth...     ^  l°"^tudinal  or  wanting    Cm>t«mo„a,. 
I  Form  lonff  and  tortuous ;  1  r\  r--j 
[     self-di4ion  transverse  |  Ophidomonas. 

Lorica  pointed  anteriorly Prorocentrum. 

Lorica  with  a  neck  and  narrow  orifice Lagenella. 


Lorica  with  orifice,  but  no    | 

neck.  1 

I  I 


Lorica  an  open  sliield 
{scutellum). 

Lorica  a  closed  box 
{urccolus). 


Cryptoglena. 
Trachelomonas. 


506  SYSTEMATIC  HISTORY  OF  THE  IKFUSOEIA. 

The  members  of  this  family  are  readily  recognized  by  the  stiffness  or  in- 
flexibility they  display  while  swimming  or  when  brought  into  contact  with 
other  bodies.  The  lorica  of  Prorocentrum  and  Lagenella  is  at  once  perceived 
to  be  a  distinct  covering.  When  any  doubt,  however,  exists  upon  this  point, 
a  slight  degree  of  pressure  upon  the  specimens  placed  in  an  aquatic  live-box, 
or  between  two  slips  of  polished  glass,  will  easily  determine  it.  The  lorica 
of  Trachelomonas  Ehrenberg  affirmed  to  be  sihcious,  and  indestructible  by 
fire.  Dujardin  has  a  parallel  family  he  names  Thecamonadina,  consisting  of 
eight  genera.  These,  however,  are  not  the  same  as  the  genera  of  Cryptomo- 
nadina  of  Ehrenberg,  of  which  only  two  are  retained,  viz.  Trachelomonas 
and  Cryptomonas.  In  the  last-named  genus  are  included  Cryptoglena  and 
Lagenella,  which  Dujardin  considers  have  no  claim  to  generic  distinction. 
Prorodon  may,  he  thinks,  be  the  same  as  his  genus  Oxyrrhis ;  and  under  the 
head  of  Trachelomonas  he  imites  Chcetotyphla  and  Choitoglena,  numbered 
among  the  Peridinisea  in  the  classification  of  Ehrenberg.  A  new  genus, 
Phacus,  is  constructed  by  the  same  author,  to  receive  those  green  organisms 
having  a  rigid  inflexible  tunic,  which  Ehrenberg  placed  with  the  flexible  and 
protean  EiiglencB.  Another  group,  styled  Diselmis,  includes  many  of  the 
Chlamidomonads  of  Ehi-enberg.  Besides  these,  thi^ee  other  new  genera,  viz. 
Crumenula,  Plceotia,  and  Anisonema,  enter  into  tliis  family  Thecamonadina, 
and  are  described  as  addenda  to  the  Cryptomonadina  of  Ehrenberg.  The 
accompanying  tabular  view  represents  at  a  glance  the  distribution  adopted  by 
Dujardin : — 

Thecamonadina. 

_    -          .^         111  f  In tegviment  hard  and  brittle...     1.  Trachelomonas. 

Body  OTOid  or  globular |  Integument  membranous. ......     2.  Cryptomonas. 

Body    flattened     or     leaf-like,  f  With  a  caudal  prolongation  ...     3.  Phacus. 
with  a  single  filament \  Without  such 4.  Crumenula. 

The  two  filaments  equal    5.  Diselmis. 

I  Body  prismatic  or  navicular  ...     6.  Plceotia. 
One  flagelUform,  one  trailing     \  Body  ovoid,  in  form  of  a  grape- 1  ^     .  „,-e^„^„,« 
[      seed,  with  two  filaments /  ' '  ^"sonema. 

With  several  filaments {  ^'a^^ort^''!^!^.'!!''"^^^^^^  ^^^''^^'- 

Perty  borrows  from  both  Ehrenberg  and  Dujardin,  by  instituting  two 
families,  Cryptomonadina  and  Thecamonadina,  and  distributes  the  several 
species  in  another  fashion,  under  new  generic  names.  The  distinctive  cha- 
racters of  the  two  famihes  are  thus  set  forth : — 

Cryptomonadina. — The  surface  of  the  body  more  or  less  hardened,  but  in- 
separable from  the  contained  substance  as  a  distinct  testa. 

Thecamo)iadina. — Possess  a  distinct  red  stigma,  and,  though  naked  at  first, 
acquire  an  apparently  separable,  brittle,  silicious  shell  or  testa,  having  an 
opening  at  its  fore  part  for  the  protrusion  of  the  filaments.  In  the  act  of 
fission  the  beings  (which  may  or  may  not  entirely  occupy  the  shell)  divide 
into  two  or  four  new  individuals. 

The  Cryptomonadina  comprise  the  genera  Cryptomonas,  Phacotus,  Anisonema, 
Phacus,  and  Lepocinclis  ;  and  the  Thecamonadina  include  Chcetotyphla,  Try- 
pemonas,  and  Chonemonas. 

Cohn  (Siebold's  Zeitschr.  1853,  Band  iv.  pp.  275-277)  sanctions  this  sub- 
division of  the  Cryptomonadina  into  two  families  ;  for  he  remarks  that  Crypto- 


OF  THE  CRYPTOMONADINA. 


507 


monas  and  Cryptoglena,  and  other  forms,  have  a  hard  integument  or  lorica 
(Panzer)  inseparable  from  the  subjacent  mass,  whi[stTrachelomonas,Lagenella, 
and  Chcetoglena  possess  a  distinct  separable  capsule  or  cyst,  within  which,  at  a 
certain  period,  the  contained  Eiiglena-like  being  can  contort  itself  and  revolve 
at  pleasure.  Moreover,  Cohn's  opinion  is  that  these  capsuled  forms  should 
be  detached  from  the  Monadina  or  Cr^-ptomonadina,  and  placed  with  the 
Euglenae.  In  this  opinion  we  entirely  coincide,  and  would  regard  the  cap- 
suled monadiform  beings  as  simply  encysted  EugUnce.  Indeed,  the  present 
state  of  knowledge,  especially  respecting  the  process  of  encysting,  irresistibly 
leads  to  the  conclusion  that  this  entire  family  Cryptomonadina  of  Ehrenberg 
must  be  broken  up,  and  its  several  forms  distributed  among  various  groups  of 
animalcules  and  plants,  as  representing  their  encysted  phase  or  condition. 

Fresenius  adds  a  new  genus  to  the  Cryptomonadina,  which  he  calls  Dre- 
jpanomonas. 

Genus  CRYPTOMOjS'AS  (XYIII.  29).— Coloiu^ed  stigma  absent;  lorica 
obtuse,  or  not  attenuated  anteriorly ;  body  short,  but  not  filiform ;  self-divi- 
sion, if  any,  longitudinal ;  llagelliform  filament  very  fine. 

Dujardin  writes,  ''  In  this  genus  Crgptomomis  1  comprise  all  Thecamo- 
nadina  mth  a  single  filament,  and  with  a  lorica  neither  hard  nor  brittle,  and 
whose  body  is  not  depressed  (compressed)  like  that  of  Phacus  or  of  Crum&nula  ; 
and  I  moreover  do  not  doubt  that  when  these  Infusoria  are  better  known, 
other  genera  may  be  distinguished  by  their  more  or  less  globular  form,  by 
the  consistence  of  theii'  envelope,  and  especially  by  their  mode  of  existence. 
I  akeady  indicate  as  subgenera,  Lagenella  with  an  elongated  lorica,  and 
Tetrabcena,  the  species  of  which  are  united  in  groups  of  foiu",  not  enclosed, 
however,  within  a  common  envelope.  As  to  the  character  supplied  by  the 
presence  of  a  red  speck  in  some  individuals,  assumed  by  Ehi^enberg  to  be  an 
eye,  I  cannot  discover  in  it  a  generic  distinction ;  nor  am  I  able  to  admit  the 
existence  of  a  lorica  open  on  one  side  (below)  like  a  shield  (carapace).  On 
the  contrary,  I  have  always  observed  the  lorica  to  be  closed  and  entire, 
though  sometimes  compressed  on  one  side,  adapting  itself  to  the  living  mass 
enclosed.  The  covering  in  every  case  is  evidently  larger  than  the  contained 
mass,  a  diaphanous  space  intervening  between  the  two  visible  in  the  form 
of  a  clear  ring."  Of  the  species  enumerated  by  Ehrenberg,  Dujardin  re- 
marks that  "  C.  curvata  is  so  compressed  that  it  is  properly  referable  to  our 
genus  Crumeiiula.^'     C.  glcmca  and  C.  fusca  he  regards  as  doubtful  species. 

Perty  briefly  characterizes  his  genus  Cryptomonas  thus  : — "  Body  an  elon- 
gated urceolus,  from  the  anterior  and  mostly-rounded  extremity  of  which  two 
filaments  are  protruded,  somewhat  exceeding  the  length  of  the  body  ;  within 
are  usually  one  or  more  dark  nuclei,  from  which  the  vesicular  germs  seem  to 
be  developed." 


Cryptomonas  curvata. — Green,  com- 
pressed, slightly  bent  like  the  letter  S, 
and  twice  as  long  as  broad.  Amongst 
Confervie.     1-570". 

C.  ovata  {Enchelys  viridis,  M.)  (xvni. 
29). — Green,  depressed  oval,  and  twice 
as  long  as  broad;  motion  slow,  vacil- 
lating, and  rotating  on  the  longitudinal 
axis,  but  when  obstructed  (says  Ehren- 
berg) is  seen  to  leap  ;  lorica  paper-like, 
not  hard ;  numerous  internal  transparent 


vacuoles  and  green  granules.  In  the 
middle  of  the  creature  there  are  two  or 
three  egg-shaped  nuclear  bodies,  and  at 
the  posterior  part  a  single  vesicle :  self- 
division  not  observed.  Found  amongst 
Confervas,    1-570". 

C.  erosa. — Green,  hyaline  anteriorly, 
depressed,  oval.  In  clean  water  among 
Conferv^e.     1-960". 

C.  cylindnca  (Enchelys  viridis,  M.). — 
Elongated,  subcylindrical,  three  times  as 


508 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


long   as    broad.      Amongst   Confervae. 
Almost  1-1000". 

C.  (?)  glauca. — Oval,  twice  as  long 
as  broad;  anteriorly  truncated  with  a 
double  flageUiform  proboscis ;  body  tur- 
gid, and  of  a  bluish-green  colour. 
Found  with  Chlamydomonas  Pulvisculus. 
1-864". 


C.  (?)  fusca. — Oval,  turgid,  and  of  a 
browm  colour.  Amongst  Confervse. 
1-1500". 

C.  lenticularis. — Orbicular,  resembling 
a  lens ;  colour  green  \  lorica  thick, 
1-1729". 


The  following  are  described  and  named  by  Dujardin : — 


C.  Globulus. — Globular,  green,  often 
with  folds  (stripes),  the  diaphanous  en- 
velope nearly  filled.  1-2600"  to  1-2250". 
This  species,  in  Perty's  opinion,  is  a 
spoinile  of  a  plant,  or  a  'sporozoid.' 

C.  incequalis.  —  Ovoid,  green,  of  less 
thickness  than  breadth,  with  a  longitu- 
dinal depression,  and  one  or  two  unequal 
notches  in  the  coloured  portion,  which 
is  always  smaller  than  the  envelope. 
1-2600".  In  stagnant  sea- water,  impart- 
ing to  it  a  green  colour. 

C.  (Lagenella)  injiata. — Ovoid,  en- 
larged posteriorly,  contracted  anteriorly ; 
envelope  transparent,  thicker  about  the 
anterior  neck-like  portion,  filled  with  a 
green  substance,  having  a  central  red 
speck ;  motion  zigzag.  1-1180".  In  a 
vessel  of  marsh-water  with  Lemna. 

C.  (Lagenella)  euchlora  (xvni.  31). — 
Ehrenberg  has  described  under  this  name 
an  Infusorium  of  the  same  size,  differing 
from  the  last  by  its  more  elongated  form, 
and  especially  by  the  green  contents  more 
completely  occuppng  the  anterior  neck- 
like portion,  w^hereas  in  ours  but  a  nar- 
row sti-eak  is  visible. 

C.  (TETRAB^a^A)  socialis. — Regularly 
ovoid,  green,  with  a  central  red  point, 
enveloped  by  a  thick  diaphanous  lorica ; 


commencing  self-  division  frequently 
seen ;  occurs  in  regular  groups  of  four 
individuals,  simply  agglutinated,  and 
having  their  filaments  directed  all  to 
the  same  side.  1-1700"  to  1-1300". 
In  a  w^ater-butt  in  the  King's  garden, 
Paris.  "I  should  have  taken,"  s^iys 
Dujardin,  "the  specimens  of  Tetrahcetm, 
socialis  at  first  for  Gonia,  if  a  trace  of  a 
common  enclosing  envelope  had  been 
found ;  yet  I  cannot  doubt  that  they  have 
the  closest  analogy  wdth  the  true  Goniu, 
and  wdth  w^hat  Ehrenberg  has  called 
Syncrypta  in  his  family  Volvocina.  One 
may  suppose  that  the  commencing  self- 
fission  observed  in  some  individuals 
would  give  rise  to  such  groups  upon  the 
desti-uction  of  the  lorica  (integimient)  in 
these  different  genera.  This  mode  of 
propagation  occurs  undoubtedly  in  most 
of  those  having  a  soft  gelatinous  integu- 
ment ;  but  in  animals  like  Trachelomonas^ 
whose  lorica  is  hard  and  brittle,  we  can- 
not miderstand  how  multiplication  does 
take  place." 

In  the  addenda  to  his  treatise,  Dujar- 
din has  this  remark :  "  I  am  convinced 
that  my  Crypto^nonas  (Tetrahcenci)  be- 
longs rightly  to  Gonium.^'' 


The  generic  characters  of  Cryptomoiias,  as  understood  by  Perty,  have  been 
detailed ;  the  following  are  the  species  he  describes : — 


C.  polymorpha. — Is  so  very  variable  in 
form  that  no  single  description  can  be 
applied  to  it.  It  ranges  between  1-840" 
to  1-300"  in  length,  and  may  be  green 
or  colourless,  browoi  or  golden  yellow, 
and  contain  at  one  time  red  specks,  at 
another  not.  The  smallest  are  usually 
yellow  or  of  a  verdigris-green :  many 
small  ones  are  hyaline  ;  the  largest  sea- 
green  and  brown.  These  changes  of 
colour  are  doubtless  due  to  the  choro- 
phyll  developed  wdthin  these  minute 
organisms,  and  to  the  modifications  this 
matter  undergoes  in  different  stages  and 
conditions  of  life — a  subject  w^ell  exa- 


mined and  illusti'ated  in  Braun's  work 
on  Rej  uvenescence  in  Nature.  In  figure, 
individual  specimens  are  oval  or  globu- 
lar, compressed,  and  emarginate.  Small 
ones  move  rapidl}',  frequently  in  circles ; 
larger  examples  more  slowly,  and  at 
times  backw^ards.  The  species  is  com- 
mon among  Confervas  the  whole  year, 
and  under  the  ice  in  winter.  Perty 
assumes  it  to  represent  the  following 
species  of  Cryptomonas  named  by  Ehren- 
berg, viz.  C.  curvata,  C.  ovata,  C.  o'osa, 
C.  cylindrica,  C.  glauca,  and  C.  fusca, 
and  also  Chilomonas  Paramecium. 


OF  THE  CRYPTOMONADINA.  509 

C.  duhia. — Quite  flattened,  elliptical,  j  sXH^di  to  Cryptoglenapigra,C.c^rulesce7iSy 
not  rounded  anteriorly ;  of  a  clear  green    and,  in   a  less  degree,  to  C.  conica  of 


colour,  with  a  hyaline  central  band, 
and,  in  most  instances,  a  red  stigma. 
Movement  rather  quick;  the  filament 
not  seen.     1-1900"  to  1-1400".     It  is 


Ehrenberg 

C.  urceolaris  (Smarda). — Belongs,  by 
reason  of  its  firm  testa,  to  the  Theca- 
monadina. 


Genus  OPHIDOMONAS. — Body  filiform ;  eye-speck  absent ;  lorica  smooth, 
obtuse,  and  tubnlai'  with  a  single  filament ;  self- division  transverse  and  com- 
plete ;  internal  vacuoles  numerous.  Its  extremely  small  transverse  diameter 
is  the  great  impediment  to  a  better  acquaintance  with  this  being.  (It  has  not 
been  figured.) 


Ophidomonas  Jenensis. — Very  thin, 
curved  spirally,  and  equally  obtuse  at 
both  extremities;  colour  olive-brown; 
motion  brisk.     In  well-water.     1-570". 


0.  sangninea, — Very  slender,  the  in- 
terspaces between  the  vacuoles  filled 
with  a  red  colour.  1-576".  In  brackish 
water. 


Genus  PBOROCENTRUM  (XVIII.  30).— Lorica  resembUng  a  Httle  box 
{xirceolus),  smooth,  pointed  at  the  anterior  extremity ;  eye-speck  absent ;  pro- 
boscis filiform  ;  vacuoles  numerous.  Self- division  has  not  been  observed.  "  It 
is  worthy  of  remark,"  says  Ehrenberg,  "  that  the  only  species  of  this  genus 
with  which  we  are  acquainted  [i.  e.  in  1838]  belong  to  the  luminous  crea- 
tures of  the  sea,  which,  perhaps  from  some  peculiar  organic  relation  or  con- 
dition, yet  unknowTi  to  us,  are  instrumental  in  producing  that  curious  and 
certainly  vital  phenomenon  usually  termed  phosphorescence."  It  may  be 
further  noticed,  that  all  the  luminous  Infusoria  of  the  sea,  hitherto  discovered, 
are  characterized  as  being  of  the  same  yellowish  waxy  colour  as  the  best- 
known  species  of  this  genus — P.  micmis ;  and  it  is  probable  that  this  condition 
is  immediately  connected  with  the  interesting  j)henomenon  in  question. 


Peobocentiiuim  micans.  —  Oval  and 
compressed,  attenuated  posteriorly,  but 
dilated  and  pointed  anteriorly  ;  colom'  of 
yellow  wax.  In  sea-water.  (x"\T:n.  30). 
Two  figm-es,  magnified  300  diameters; 
the  first  is  a  side  view,  the  latter  a  back 
view ;  the  filament  in  the  foi-mer  indi- 


cates   the    position    of    the    supposed 
mouth.     1-430". 

P.  viritlis. — Ovate,  suborbicular,  tur- 
gid ;  posterior  end  rounded ;  anterior 
shortly  pointed  ;  colour  green,  1-1100". 
In  the  Baltic. 


Genus  LAGE:N"ELLA  (XVIII.  31).— Distinguished  from  other  loricated 
monads  by  the  lorica  being  extended  anteriorly,  or  flask-shaped.  The  lorica 
is  perfectly  distinct,  and  crystalline.  Within  are  the  bright-red  speck  and 
green  granules.  (Vide  Cryptomonas  LageneUa,  p.  508,  and  ChonemonaSf 
Perty,  p.  513.) 

Lagenella  euchlora  (xviii.  31).  —  I  crj^stalline ;  colour  green.  Amongst 
Oval,  neck  short  and  truncated ;  lorica  |  Confervse.     1-1200". 

Genus  CBYPTOGLENA  (XVIII.  32).— Lorica  open,  in  the  form  of  a  shield 
(scutellum),  folded  or  roUed  inwardly  at  the  sides,  and  without  a  projecting 
neck.  Eye-speck  distinct ;  granules  green  in  aU  the  species.  La  C.  conica 
two  oval  greyish  masses  are  seen  in  the  centre,  and  also  two  filaments.  Self- 
division  not  observed.  These  characters,  given  by  Ehrenberg,  are  valueless  to 
distinguish  Gryptoglena  from  other  Crj-ptomonadina,  or  from  Chlamydococcus. 
The  scuteUar  form  of  the  lorica  is  an  error ;  for  it  forms  a  complete  investment, 
intennipted  only  at  the  point  where  it  gives  exit  to  the  filaments.  The  red 
eye- speck  is  no  distinction,  as  so  often  remarked ;  and  the  absence  of  a  neck- 
like extension  of  the  lorica  is  seen  in  Cryptomonas,  Chlamydococcus,  and  other 
genera.  Carter  describes  one  species  with  four  filaments.  We  unite  with 
Dujardin  in  rejecting  this  as  an  independent  genus. 


510 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA 


Crypto  GLENA  conica  (x-\tji.  32).  — 
Conical,  anteriorly  dilated  and  trun- 
cated ;  filaments  two,  half  the  length  of 
the  body ;  posterior  end  acutely  attenu- 
ated. Colour  bluish-green.  Abundant 
in  river  water,  in  company  with  Orypto- 
monas  glmica,  from  which  they  are 
readily  distinguished  by  their  form, 
larger  size,  and  red  eye.  They  move 
briskly  in  the  direction  of  the  longitudi- 
nal axis  of  their  bodies,  but  when  ob- 


structed spring  or  leap  out  of  their  direct 
course.     1-1100". 

C.  pigra. — Oval,  approaching  to  glo- 
bular, and  emarginate  anteriorly ;  colour 
a  beautiful  green ;  movement  slow.  In 
water  when  covered  with  ice.     1-3000''. 

C.  cesrulescens. — Depressed,    elliptical 
and  emarginate  anteriorly ;  colour  bluish 
green;  motion  quick, 
fervte.     1-6000". 


Amongst  Con- 


Mr.  Carter  has  added  and  figured  some  new  species,  viz. — 


C.  lenticularis  (A.  N.  H.  1858,  p.  253). 
— Spherical,  compressed  ;  lorica  distinct 
and  stout;  endochrome  separated  from 
it  by  a  distinct  clear  zone ;  contrac- 
tile vesicle  seated  at  the  point  of  in- 
sertion of  the  two  filaments,  where 
there  also  seems  to  be  an  interruption 
in  the  continuity  of  the  lorica  (emar- 
ginate) ;  eye-speck  on  one  side,  nucleus 
visible.  The  horizontal  view  is  ovate, 
and  acuminate  at  both  ends.  Fission 
takes  place  in  the  power  of  two,  just 
as  in  Chlamydococcus,  from  which  in- 
deed no  satisfactory  distinctive  fea- 
tures are  perceptible  in  the  engravings 
furnished. 

C.  corcliformis. — Distinguished  by  its 
cordiform"  lorica.  The  contents  are  orbi- 
cidar,  and  do  not  nearly  fill  the  lorica ; 
filaments  four  ;  a  resting-stage  perceived, 
wherein  the  contents  are  covered  by  a 


into 


thick   envelope,    and  are    divided 
numerous  cells  (microgonidia.) 

C.  angulosa  {A.  N.  H.  1859,  iii.  18).— 
Lorica  compressed,  oblong,  angular, 
shield-shaped,  transparent,  round  poste- 
riorly, square  anteriorly,  where  it  pre- 
sents a  short  neck  in  the  median  line  for 
the  passage  of  the  cilia;  border  thin, 
cm-led  up  posteriorly  and  anteriorly  on 
opposite  sides.  Internal  or  gTeen  cell  at 
some  distance  from  the  lorica,  angidar, 
lined  with  chlorophyll,  provided  with 
two  cilia,  which  issue  through  the  neck 
of  the  lorica ;  two  contractile  vesicles  at 
their  base;  an  eye-spot  median  and 
peripheral,  and  one  to  four  starch-cells 
of  a  circidar  form.  Swimming  with  its 
cilia  forwards  in  an  extremely  irregidar 
line.  Length  of  lorica  1-1080",  and 
breadth  1-1800".  Freshwater  tanks  in 
the  island  of  Bombay. 


Genus  TRACHELOMONAS  (XYIII.  33, 34 ;  XIX.  9-11).— Have  a  single 
long  filament,  an  ej^e-speck,  and  a  closed  elongated  or  spherical  lorica,  with- 
out a  projecting  neck.  Yery  minute  transparent  vesicles  have  been  discerned 
in  T.  nigncans  and  T.  volvocina.  It  is  probable  that  some  of  the  highly  inter- 
esting animalcules  which  enter  so  abundantly  into  the  silicified  substances  in 
certain  chalk  formations  belong  to  this  genus.  The  genus  Trypemonas 
(Perty)  is  equivalent  to  this,  the  characters  of  which  are  hereafter  given  at 
large  in  Perty's  words  (p.  513). 

Trachelomonas  nigricans.  —  Oval, 
approaching  to  globular;  colour  rarely 
green,  mostly  of  a  reddish  or  blackish 
brown.     Eye-speck  brown.     1-1700". 

T.  volvocina  (x^^n.  33,  34 ;  xix.  9, 10). 
— Spherical,  with  a  delicate  filament; 
colour  mostly  green,  sometimes  of  a 
bro-^mish  hue,  with  a  distinctive  red 
ring  around  the  body :  between  the  in- 
ternal vesicles  is  a  very  fine  granulated 
substance,  to  which  the  colour  of  the 
body  is  due.  The  red  circle,  so  re- 
markable a  featm-e  in  this  species, 
always  appears  in  the  same  horizontal 
position,  how  quickly  soever  the  creature 
may  be  revolving  on  its  long  axis.  The 
uppermost  figure  represents  the  flabellum 


extended ;  in  the  next  it  is  retracted ;  the 
lowest  of  the  three  is  a  very  young  spe- 
cimen; and  34,  a  full-groTvn  one  that 
has  been  forcibly  pressed  and  the  lorica 
broken.     Amongst  Confervas.     1-860". 

T.  cylinclrica  (xix.  11). — Oblong,  ap- 
proaching to  cylindrical ;  filament  almost 
as  long  as  the  body.  Colour  a  beautiful 
green ;  eye-speck  red ;  ring  purple. 
1-1000".  Perty  points  out  the  fact  that 
T.  nigricans  is  nothing  more  than  an 
old  specimen  of  this  species,  brown  and 
opake  by  age. 

T.  areolata, — Globose,  surface  areo- 
lated. 

T.  aspera. — Similar  to  preceding,  but 
its  surface  covered  with  rough  points. 


OF  THE  CKYPTOMONADINA.  511 

T.  granulata.— Similar,  but  its  surface  I  tween  tlie  surface  of  this  and  the  two  pre- 
very  minutely  granulated.  I  ceding  are  too  trivial  to  be  characteristic. 

T.  /^m.— Globose,  with  its  surface  I  T.  pyrinn.  —  Oblong  or  pear-shaped 
smooth.      The  assigned  differences  be-  I  (pyiiform),  smooth, 

Dujardin,  in  his  family  Thecamonadina,  includes  some  genera  of  animalcules 
not  described  by  Ehrenberg,  or  described  by  him  under  different  names  and 
according  to  a  different  arrangement.  They  are  appended  here  as  best  agree- 
ing with  the  Cryptomonadina. 

Genus  PHACUS  (D.). — Body  flattened,  leaf-like,  and  mostly  green.  It 
displays  a  red  speck  in  front,  together  with  a  flagelliform  filament ;  and  the 
resistant  membranous  integument  is  prolonged  posteriorly  in  the  form  of  a  tail. 

''  Three  out  of  the  foiu'  species  are  referred  by  Ehrenberg  to  his  genus 
Euglena,  on  account  of  similarity  in  colour.  The  difference  between  the  two 
genera  is,  however,  considerable  ;  for  in  Euglena  the  integument  is  contractile, 
and  pennits  of  a  frequent  change  of  form,  whilst  in  Pliacus,  on  the  contrary, 
the  integument  appears  quite  wanting  in  contractility,  and  the  animal  inva- 
riable in  form. 

"  The  enclosing  integument  of  Phacus  persists  after  the  death  of  the  animal 
and  the  destruction  of  the  contained  green  mass,  and  also  after  the  action  of 
various  chemical  agents,  becoming,  in  the  latter  cases,  quite  transparent. 
The  motor  fflament  disappears  with  the  living  contents;  globules  of  the 
latter  remain  after  death." 

Mr.  Carter  (A.  N.  H.  1856,  xviii.  p.  241)  describes  a  single,  glairy,  discoid, 
capsuled  body  in  the  centre  of  Pliacus,  as  well  as  in  the  large  lip  of  Crume- 
nida  texta. 

1.  Phacus pleuronecteszzzEiiglena pleuronectes  ;  2.  PAongicauda=^E.longi- 
cauda ;  and  3.  P.  triquetra  =  E.  triquetra.     (See  Euglena.) 

The  new  species,  of  which  the  characters  are  given,  is 


Phacus  tripteris.  —  Oblong,  with 
three  longitudinal  plaits  meeting  along 
the  axis,  rather  twisted  on  the  midrib, 


with  a  red  speck  in  front  and  a  dia- 
phanous caudiform  prolongation  behind. 
1-420"  to  1-312". 


Genus  CEUMENULA  (D.)  (XXVI.  6).— Oval,  compressed,  covered  by  a 
resistant  iategument  (testa)  apparently  reticulated,  sending  out  a  long  flagelli- 
form filament  obliquely  from  a  notch  in  the  anterior  border.  Motion  slow. 
There  is  no  tail-like  prolongation,  as  in  Phacus.    A  contractile  vesicle  present. 

CnuiiENULA    texta.  —  Envelope    re-  !  pointed  sigmoid  fibres  ai-ranged  parallel 
ticular,  filled  with  a  green  matter,  toge-  I  to  each  other,  so  as  to  form  a  conical 
ther  with  vacuoles  or  hyaline  globules,  '  cell,  which  remains   behind  when   the 
and  having  a  large  red  globule  anteriorly,  j  softer  contents  have  dispersed. 
1-520".     Testa  persistent  after  death.  The  anterior  notch  is  produced  by  a 

In  this  species  Mr.  Carter  {op.  cit.  sort  of  overhanging  lip.  The  filament 
p.  119)    describes    an  inner    layer    of  !  is  three  times  longer  than  the  body. 

Genus  DISELMIS  (D.). — Ovoid  or  globular,  covered  by  an  integument,  not 
contractile,  of  almost  gelatinous  consistence ;  two  equal  locomotive  filaments 
proceed  from  the  anterior  extremity. 

"  This  genus  nearly  corresponds  to  the  Chlamydomonas  of  Ehrenberg,  placed 
by  him  in  the  family  Volvocina  by  reason  of  its  apparent  self-division  into 
two  or  foiu"  segments  within  the  testa.  Dujardin,  on  the  other  hand,  admits 
none  as  Volvocina  which  do  not  exhibit  an  aggregation  of  perfect  individuals 
withia  a  common  envelope." 

The  removal,  by  Dujardin,  of  the  Chlamydomonads  described  under  this 
name  of  Disehnis,  from  Volvocina  to  Crj^ptomonaduia,  is  generally  held  to 
be  an  error,  dependent  on  an  imperfect  conception  of  their  characters  and 
true  affinities.    (See  genus  Chlamybomonas.) 


512 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


The  integument  of  Disehnis  is  non-resistant,  diaphanous,  breaks  up  after 
death  by  diffluence,  and  is  sometimes  filled  with  a  green  substance.  Like 
plants,  these  beings  are  sensitive  to  light,  fix  themselves  to  the  lightest  part  of 
the  containing  vessel,  and  disengage  oxygen  when  exposed  to  the  sun's  rays. 
In  the  green  substance  are  seen  granular  masses,  a  disk  with  an  expanded 
border,  and  a  red  speck.  The  motor  filaments  proceed  from  the  same  opening 
of  the  integument,  and  often  form  a  diaphanous  lobe  projecting  from  the 
opening.  The  red  colour  oftentimes  seen  in  the  water  of  the  Mediterranean 
appears  due  to  Infusoria  of  this  genus. 


DiSELMis  viridis  =  Chlamydomonas 
pulviscidus  (Ehr.)  (xix.  16). 

D.  marina. — Nearly  globular,  obtuse 
and  rounded  in  front,  granular  within. 
1-1050". 

This  species  is  larger  than  D.  viridis, 
more  globular,  and  apparently  deficient 
of  the  red  speck.  In  stagnant  sea-water 
of  a  green  colour. 

D.  angusta. — Pyriform,  oblong,  ap- 
pearing to  be  plaited    and    tubercular 


inside,  sometimes  with  an  indistinct  red 
speck.     1-2600"  to  1-1850". 

D.  Dunalii.  —  Oval  or  oblong,  often 
constricted  about  the  middle ;  colom-less 
when  very  young,  then  green,  afterwards 
red ;  with  2  flagellifonn  filaments  longer 
than  the  body,  seated  on  a  projecting  and 
retractile  anterior  lobe.  Interior  occupied 
by  coloured  globides.  Discovered  by 
M.  Joly  to  be  the  chief  cause  of  the  red 
coloiu"  of  the  water  of  the  Mediterranean. 


Genus  ANISONEMA  (D.)  (XIX.  8;  XXYI.  8).— Colourless,  oblong,  more 
or  less  compressed,  having  a  resistant  envelope  giving  exit  by  an  opening  to 
two  filaments,  one  dii'ected  forwards  and  flageUiform,  the  other  trailing  back- 
wards and  retractile ;  movement  slow. 

*'  In  other  genera,  as  in  Hetei^omita,  two  similar  filaments  exist ;  but  the 
present  genus  is  known  by  its  non- contractile  resistant  integument,  which  is 
often  met  with  empty  and  transparent.  It  may  be  that  the  Bodo  grandis 
(Ehr.)  is  allied  to  this  genus  as  weU  as  to  Heteromita.'^ 

trailing :   he  supposes  it  in   the  act  of 
fission ;  but  his  figure  does  not  show  it. 

A.  sidcata  (xxvi.  8). — Oval,  depressed, 
with  4  to  5  longitudinal  furrows,  and  an 


Anisonema  Acinus  (xix.  8). — Oblong, 
depressed,  rounded  posteriorly,  and  nar- 
rower in  front,  like  the  seed  of  an  apple, 
with  an  opening  close  to  the  apex; 
colourless  and  transparent,  except  a  few 
vesicles,  mostly  green,  but  occasionally 
red ;  movement  in  a  straight  line  for- 
wards.    1-1300"  to  1-850".     In  pond- 


oblique  notch  in  front,  from  which  the 
two  filaments  proceed ;  moYement  vacil- 
lating, circular.  Perty  has  seen  it  divide 
longitudinally.  1-1300".   The  projecting 


water.  This  species  =  Bodo  grandis  (?)  filament  is  t£ree  times,  and  the  floating 
(Ehr.).  Perty  gives  afigm-eofan  organ-  j  one  about  twice  as  long  as  the  body; 
ism  he  identifies  with  this  species,  hav-  j  in  this,  however,  says  Perty,  there  is  no 
ing  four  filaments  anteriorly  and  none  \  constancy. 

Genus  PL(EOTIA(D.)  (XXYI.  10,  a,  6).— Diaphanous,  having  several  ribs 
or  longitudinal  ridges  along  the  middle,  and  a  circular  translucent  margin,  giving 
the  whole  a  navicular  fonn ;  two  locomotive  filaments  proceed  from  one  end. 

This  distinct  fonn  might  be  mistaken  for  one  of  the  Bacillaria,  were  not 
the  filaments  clearly  visible.  The  characters  of  the  filaments  are  similar  to 
those  of  Anisonema — one  extending  forwards  with  an  undulatory  movement, 
the  other  trailing  and  capable  of  suddenly  arresting  the  movement  of  the 
body  by  its  adhesion  and  power  of  retraction. 

Plceotia  vitrea  (xxvi.  10  a,  h). — Hy-  I  1-130" ;  movement  slow.     In  sea-water 
aline,  with  3  to  4  longitudinal  salient  I  kept  for  two  months, 
lines  at  the  centre,  and  some  granules.  I 

Genus  OXYERHIS  (D.)  (XXYI.  9  a,  6).  — Ovoid,  oblong,  obUquely 
notched  in  front,  and  prolonged  into  a  point ;  several  flagelliform  filaments 
proceed  laterally  from  the  bottom  of  the  fissure. 


OF  THE  CRYPTOMONADII^A. 


513 


The  name  is  indicative  of  the  elongated  apex.  These  Infusoria  being  but 
imperfectly  known,  one  species  only  is  described : — 

OxYEEHis  marina  (xxvi,  9  a,  b.) — Colourless  j  subcylindrical  rugose,  rounded 
posteriorly.    1-520".     In  the  Mediten*anean. 

The  next  thi-ee  genera  are  taken  from  Perty,  the  first  being  one  of  his 
Cryptomonadina,  the  others  Thecamonadina : — 

Genus  PHACOTUS  (XIX.  7,  a,  b,  c).— Body  round,  biconvex,  ^dth  two 
(possibly  four)  filaments. 

Phacotus  viridis. — Green,  usually 
divided  through  the  middle  by  a  clear  or 
a  dark  line.  Margin  acute ;  the  central 
part  more  or  less  convex,  sometimes 
elevated  into  a  sharp  angular  ridge,  ren- 
dering the  fig-ure  fom"-sided.  The  shell 
shows  a  double  contoui',  and  persists 
some  days  after  the  death  of  the  indi- 


vidual. Medium  size  1-1440".  Among 
Confervas.  Bern.  It  =  Cn/pfo?nonas 
lenticidaris  (E.).  Like  Dujardin,  Perty 
removes  Clicetotijphla  and  ChcBtoglena 
from  the  Peridinisea  to  the  Thecamo- 
nadina. The  foimer  genus  he  retains, 
but  merges  the  latter  in  his  group 
CJionemonas. 

Genus  TRYPEMOXAS  =  generaUy  TEACHELOMOXAS  (Ehr.)  (XIX.  9, 
10, 11). — Shell  globular  or  elliptic,  with  a  small  round  apertui'e  (the  elevated 
margin  of  which  frequently  produces  a  funnel-Like  appearance),  from  which 
the  filament  protrudes  ;  colour  green,  with  a  red  stigma ;  lorica  at  first  hyaline, 
then  purj)lish,  and  lastly  brown,  thick  and  opake  ;  not  armed,  but  apparently 
porous  from  the  presence  of  numerous  pimcta  indicating  the  absence  of 
deposit,  as  elsewhere.  Perty  justly  objects  to  the  term  Trachelomonas,  as 
prone  to  cause  confusion  of  ideas  from  its  etymology  signifying  beings  with 
necks,  which  none  of  those  it  includes  possess. 

Trypemoxas  volvocina  (xix.  9,  10)  =  Trachelomonas  volvocma ;  and  T.  cylindrica 
(xix.  11)  =  Trachelomonas  cylindrica  and  T.  nigricans  (Ehr.). 

Genus  CHOXEMOXAS  (XYIII.  35  a,  b,  c,  cZ).— Green  with  a  red  stigma ; 
testa  hard,  ellipsoidal,  with  a  funnel-shaped  opening  at  the  anterior  end — from 
which  tivo  filaments  proceed.  It  represents  in  part  the  genera  CJicetogUna, 
Pantotrichum,  and  Lagenella  (E.). 

in  pools  of  snow-water,  and  beneath  the 
ice.  Two  varieties  occm* : — a.  glabra, 
with  a  smooth  lorica,  which  is  no  other 
than  the  Lagenella  euchlora  (E.)  ;  6. 
imijilis,  Tsdth  a  single  filament,  equiva- 
lent to  ChcBtoglena  volvocina  (E.).  The 
very  hispid  examples  of  this  Chonemonas 
are  =  Pantotrichum  Lagenula,  placed  by 
Ehrenberg  among  his  Cyclidina. 

C.  acuminata.  —  Shell  oval,  strongly 
pointed  posteriorly ;  bristles  scarcely  ob- 
servable. Fimnel  at  front  distinct. 
1-500".  Hyaline  and  quite  smooth  speci- 
mens also  occurred.    On  the  St.  Gothard. 


Chonemonas  Schrankii  (x\tji.  35  a, 
b,  c,  d),  formerly  named  C.  hispida. — 
Lorica  clear  or  dark  bro\\Ti,  more  or  less 
spinous.  Filaments  double  the  length, 
and  hyaline.  Portions  of  the  lorica  ex- 
hibit apparent  pores,  and  empty  speci- 
mens often  decussating  lines.  The  gi'een 
contents  escape  imhuii;  on  fi'actming 
then'  enclosing  case,  which  they  gene- 
rally do  not  fill.  When  fission  proceeds, 
the  contents  alter  their  form,  and  the 
filaments  disappear.  Onward  movement 
not  rapid,  seldom  oscillating,  but  actively 
revolving.    1-900"  to  1-540".    At  Bern, 


Genus  DREPAXOMOXAS  (Fresenius). 


Drepanomonas  <7ewtote. — Colomiess; 
falcifoi-m,  compressed;  pointed  at  each 
end,  \s-ith  five  outspreading  furrows,  of 
which  two  are  on  either  flat  side,  and 
one  on  the  convex  edge.  In  the  centre 
of  the  concave  smface  is  a  ventricose 
swelling  with  a  small  tooth-like  process ; 
a  similar  process  is  remarked  beneath 


the  apex.  From  near  the  last,  several 
lines  extend  upwards  and  outwards.  In 
one  aspect  an  undulating  line  is  percep- 
tible along  the  convex  margin;  this  is 
also  \TLsible  in  the  loricae  of  dead  speci- 
mens. Internally  are  only  colom-less 
granules,  imparting  a  pearly  hue.  On 
one  occasion  a  vacuole  was  seen  ha^ino- 
2l 


514 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


a  reddish  glimmer ;  possilily  a  contrac- 
tile vesicle ;  movements  slow ;  no  con- 
tractions of  fig-ure  observed.  Botli  ends 
fumislied  with  delicately  motile  fila- 
ments,   those    on    the    anterior    longer 


than  those  on  the  posterior  extremity; 
but  still  seen  with  difiicult3\  In  swim- 
ming it  lies  on  the  flat  surface ;  it  also 
revolves  on  its  long  axis.  1-15'"  to  1-14'". 
In  water  from  Walldorf. 


FAMILY  IV.— YOLYOCINA.     (See  p.  144.) 

(XIX.  32-69 ;  XX.  22-47). 

This  family  derives  its  name  from  the  genus  Volvox,  and  from  the  rolling 
motion  with  which  the  beautiful  creatures  belonging  to  it  make  their  way 
through  the  water.  They  resemble  the  Monads  in  most  particulars  relating 
to  their  organization ;  have  an  unvai^jing  form,  and,  except  a  filament,  no 
appendages ;  vacuoles  present.  ^Tiilst  propagation  by  self-division  is  pro- 
ceeding, and  the  young  are  increasing  in  size,  the  suiToundiug  envelope  or 
lorica  is  observed  to  expand  in  a  corresponding  degree,  but  continues  entire 
until  its  numerous  occupants  have  come  to  maturity,  when  it  bursts  and  sets 
them  at  liberty. 

All  the  genera  are  provided  with  organs  of  locomotion,  which  consist,  as 
^ith  the  Monads  and  Cryptomonads,  of  a  single  or  double  very  delicate  fila- 
ment ;  and  hence  it  is  that  when  they  are  clustered,  the  entire  grouji  appears 
to  be  cihated,  or  beset  with  hairs.  Besides  granules,  one  or  two  round  nuclei 
and  a  contractile  sac  are  present. 

This  family  Ehrenberg  disposed  into  ten  genera — five  ftimished  with  a  red 
stigma,  situated  at  the  anterior  part  of  the  body,  and  five  without  it.  In  the 
former,  a  sensitive  system  was  presumed  on  the  supposition  of  the  red  speck 
being  an  eye. 

The  following  is  an  analysis  of  the  family : — 


Tail 

absent  | 


( 


\'ibrating 
filament    absent 


Lorica  box-hke 


i    Gyges. 


Lorica  single  * 


j         vibrating        ^ 
l^  filament  present  J 


Pandorina, 


Clusters  tabulated  or  in  plates    Gonium. 

^  Lorica  double   Syncrypta. 

Tail  present    Synm-a. 

(^  Tail  present  Uroglena. 

Self-division         both    j 

equal   and    perfect  \  {  filament  single    . . .  Eudorina. 

(no  internal  globes)      Tail  absent 


filament  double  . . .  Clilamydomonas. 

{  Filament  single    Sphterosira. 
Filament  double  Yolvox. 

The  above  account,  derived  from  Ehrenberg's  work,  afifords  a  very  imperfect 
conception  of  the  Yolvocina,  especially  of  their  structui-al  characteristics  as  a 
family, — a  defect  we  have  endeavoured  to  supply  in  the  chapter  on  their 
general  history  (p.  144).  Moreover,  as  there  noticed,  these  beings  are 
numbered  by  the  majority  of  naturalists,  at  the  present  day,  among  plants, 
although  a  respectable  minority,  among  whom  are  Thiu^et  and  Laehmann, 
incline  to  the  opinion  that  they  are  for  the  most  part  animals,  as  Ehrenberg 
represented.  Thuret  expressed  this  opinion  now  several  years  since,  when 
the  physiology  of  the  simplest  vegetable  organisms  was  imperfectly  imder- 


OF  THE  VOLVOCINA.  515 

stood,  and  supported  it  on  the  fact  that  an  act  of  germination,  similar  to 
that  seen  among  the  spores  of  the  lower  Algae,  was  never  witnessed  among 
the  Yolvocina.  This  absence  of  a  supposed  vegetable  characteristic,  more 
recent  researches  appear  clearly  to  set  aside  as  an  argument  against  the 
vegetable  natui^e  of  a  doubtful  organism ;  for  in  the  whole  cycle  of  life  of 
many  of  the  simplest,  or  so-called  unicellular  plants,  an  act  of  germination, 
as  understood  by  Thuret,  never  occm's.  Dujardin,  when  he  published  his 
work  on  Infusoria  in  1841,  admitted  the  Volvocina  among  animalcules,  but 
proposed  a  diiferent  distribution  of  theii'  genera  to  that  put  forward  by 
Ehrenberg.  Thus,  he  transferred  Gyges  and  Chlamydomonas,  owing  to  their 
not  being  aggregated  mthin  a  common  envelope,  to  the  Thecamonadina,  and 
united  Eudorina  with  Pandorina  (XIX.  59-69),  and  Synura  T\ith  Uroglena, 
because  he  could  not  regard  the  presence  or  absence  of  a  red  speck  to  be  a 
generic  characteristic.  Fiu'ther,  he  considered  Syncryi^ta  a  doubtful  genus, 
and  combined  Sphceroswa  with  Pandorina. 

Although  the  present  state  of  science  proves  that  the  appearance  of  a  red 
speck  or  specks  in  a  monadiform  being  is  mostly  a  transitory  phenomenon, 
associated  with  a  certain  condition  or  phase  of  existence,  and  that  therefore 
the  union  of  Eudorina  with  Pandorina,  and  of  Synura  with  Uroglena,  is  a 
correct  proceeding,  yet  Dujardin  erred  both  in  detaching  Gyges  and  CJdamy- 
domonas  (XIX.  16)  from  the  Yolvocina,  and  in  considering  Sj^ha^rosira  and 
Pandorina  modifications  of  a  common  form.  The  relation  of  Cidamydomonas 
to  the  Yolvocina  has  been  weU  shown  by  Cohn,  Braun,  and  others ;  and 
Gyges  itself  might  probably  be  dispensed  with  as  a  distinct  genus,  since  there 
is  good  evidence  to  show  that  its  species  are  simply  stages  of  development  of 
Chlamydococcus  or  Protococcus  (XIX.  20-31),  and  of  Chlamydomonas.  Again, 
Sjfhcerosira,  instead  of  being  a  varied  phase  of  Pandorina,  is  a  member  of  the 
genus  Volvox  ;  indeed  Prof.  Busk  incHnes  to  the  notion  that  it  is  merely  a 
developmental  stage  of  the  common  Vohox  GJohator  (T.  M.  S.  i.  p.  39).  Perty, 
however,  advances  as  an  argument  for  its  independent  natiu-e,  that  it  is  com- 
mon about  Bern,  whilst  Volvox  Globator  is  not  met  Avith.  This  fact  speaks 
at  least  for  the  specific  independence  of  Splicer osir a,  although  its  generic 
must  be  given  up.  Moreover,  a  genus  Botryocystis  was  instituted  by  Kiitzing, 
of  the  independence  of  which,  however,  there  is  no  good  evidence.  The  con- 
dition of  Protococcus  pluviaJis  (Cohn,  Ray  Soc.  1853,  p.  559),  when  di\ided  into 
sixteen  segments,  con'esponds  to  the  Botryocystis  Morum.  Fiu^ther,  the  last- 
cited  author  in  another  treatise  (EntiuicJc.  d.  Mikrosl^op.  Alg.  und  Pike,  p.  209) 
treats  Botryocystis  as  synonymous  vrith  Pandorina,  and  in  this  agrees  with 
Prof.  Henfrey,  who  remarks  {M.  T.  1856,  p.  51)  that  the  form  of  Pandorina 
which  produces  the  resting-spores,  after  losing  its  cilia,  is  Kiitzing's  Botryo- 
cystis  Morum.  Perty  coins  two  new  genera,  called  SynapTiia  and  Hirmidium 
(XIX.  15).  Cohn  points  out  a  natural  division  of  the  Yolvocina  into  two 
sections,  in  the  fii^st  of  which,  represented  by  Chlamydomonas  and  Chlamy- 
dococcus, the  fission  of  each  primordial  cell  is  complete,  and  the  products 
single  and  unicellular,  whilst  in  the  second  section,  including  all  the  rest  of 
the  Yolvocina,  the  cells  formed  by  the  fission  of  the  parent  primordial  cell  con- 
tinue united  in  groups  or  clusters.  The  difference  between  the  several  genera 
obtains  from  the  disposition  of  the  produced  eeUs ;  and  this,  again,  depends  on 
the  dii-ection  of  the  line  of  fission.  Thus,  in  Stephanosphcvra  (XIX.  38-52) 
the  plane  of  fission  is  the  meridian  of  the  sphere  ;  in  Gonium  it  occurs  in  two 
planes  at  right  angles  to  each  other,  and  in  Volvo.v  and  its  aUies  in  three 
planes.  If  the  Yolvocina  are  referable  to  the  vegetable  kingdom,  they  consti- 
tute a  family  of  the  order  Palmellaceae  (Chamaephjxea?,  K.),  among  the  Algae. 
The  separation  of  Syncrijpta  from  Gyges,  and  its  independent  generic  ex- 

2l2 


516 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


istence,  are  very  questionable  ;  for  the  possession  of  a  double  iorica,  attributed 
to  ^yncrypta  by  Ehrenberg,  cannot  seiTe  as  a  generic  distinction  from  Oyges, 
with  a  single  Iorica,  since  Cohn  has  shown  in  Chlamydococcus  that  the  pro- 
duction of  a  distinct,  loosely  investing,  and  apparently  second  covering,  is  one 
of  the  series  of  developmental  phenomena  in  the  selfsame  being.  The  same 
statement  is  true  of  the  so-called  tail  which  is  used  to  separate  Symira  from 
other  allied  forms  ;  for  caudate  beings  make  their  appearance  in  the  cycle  of 
existence  of  non-caudate :  thus  a  caudate  variety  of  naked  "  zoospore  "  re- 
sembling a  Bodo  is  represented  by  Cohn  in  his  illustrations  of  the  multiform 
phases  of  Protococcus.  The  presence  of  a  mouth,  and  the  construction  of  the 
envelope  with  one  side  or  end  open,  through  which  the  animal  can  protrude 
itself  at  will,  are  statements  now  generally  ignored. 

After  excluding  the  inadmissible  and  the  very  doubtful  genera  of  this 
family  of  Ehrenberg,  there  remain  only  Pandorina,  Gonium,  Chlamydomo- 
nas,  and  Volvox.  To  these,  other  natiu-ahsts  add  Chlamydococcus  (Braun), 
Glceococcus  (Braun),  Stephanosphcera  (Cohn),  and  Stephonoma  (Werneck). 
Ehrenberg  himself  has  added  a  new  genus  he  names  Trochogonium ;  but,  from 
the  imperfect  description  given,  it  is  not  possible  to  decide  accurately  whether 
it  is  distinct  from  some  of  the  genera  instituted  by  other  naturalists. 

Genus  GYGES. — Lorica  of  a  simple  box-like  form  (urceolus)  ;  eye-speck 
and  '  tail '  absent ;  filament  doubtfully  present ;  the  internal  organization  is 
Httle  known.  Two  species  are  mentioned  by  Ehrenberg,  both  of  a  green 
colour  and  enclosed  in  a  transparent  lorica. 

Gyges  Gramdum  (Volvox  Granulum, 
M.). — Oval,  or  nearly  globular;  con- 
tained granules  of  a  darkish  green  colour. 
Amongst  Lemnas  and  Conferv?e.  1-1150". 

According  to  Cohn  (on  Protococcus, 
p.  559)  the  encysted  motile  zoospore 
(xix.  31)  oi  Protococcus  (  Cldamydococcus) 


pluvialis  is  the  same  as  this  species  Gyga 
Gramdum',  whilst  the  same  zoospores  di- 
vided into  two  must  be  regarded  as  the 
next  species,  Gyges  bipartitus. 

G.  bipartitus. — Crystalline,  gelatinous, 
and  nearly  spherical ;  the  superficies  co- 
lourless, but  its  granular  contents  yel- 
lowish green ;  it  is  sometimes  seen  di- 
vided into  two,  at  others  as  a  simple 
sphere.     Amongst  Confervas.     1-480". 

G.  sanguineus. — Oval,  red,  inclining  to 
crimson,  surroimded  by  a  broad  colour- 
less ring  representing  the  enveloping 
lorica.  This  species  was  discovered  by 
Mr.  Shuttleworth  in  the  red  snow  which 
fell  at  the  Grimsel  in  August  1839.  Its 
motion  is  lively.  Group  527  (x'^ii.) 
shows  several  highly  magnified.  Found 
with  Astasia  nivalis  and  Monas  gliscens, 
among  the  globules  of  Protococcus  nivalis 
{Ed.  Phil.  Journ.  v.,  xxix.).  1-1200"  to 
1  -300' '.  This  is  probably  only  the  '  still ' 
phase  of  Chlamydococcus  pluvialis. 

M.  Vogt  gives  a  very  singular  account 
of  the  mode  of  reproduction  of  this 
being.  He  says,  "  It  gives  off"  from  se- 
veral parts  of  its  body  small  transparent 
buds,  apparently  vesicular,  and  for  the 


most  part  fiUed  with  granular  matter. 
As  they  enlarge  they  become  gradually 
detached ;  sometimes  two  of  equal  size, 
of  which  one  is  red  and  loricated,  the 
other  colomiess,  adhere  by  a  very  narrow 
point  of  attachment,  which  subsequently 
gives  way,  and  the  bud  appears  as  an 
Infusory  animal,  like  what  Mr.  Shuttle- 
worth  has  represented  in  his  7th  and  8th 
figures,  and  which  approaches  Pandorina 
hyalina  (Ehr.)." 

This  account  of  the  reproduction  of 
this  species  of  Gyges  is  so  peculiar  and 
exceptional,  that  the  questions  arise 
whether  it  really  is  a  member  of  this 
genus  and  family,  and,  if  it  be,  whether 
the  description  is  a  correct  interpretation 
of  the  facts  observed. 

M.  Vogt  adds  that  Gyges  sanguineus 
ought  not  only  to  be  looked  upon  as  the 
type  of  a  new  genus,  but  even  of  a  new 
familj^,  on  account  of  its  very  peculiar 
mode  of  reproduction.  He  farther  de- 
scribes a  new  species  : — 

G.  Vogtii. — Globular,  containing  in  its 
interior  from  two  to  five  individuals, 
enveloped  by  an  apparently  silicious 
lorica ;  colour  dark  red  ;  frequently  found 
adherent  and  arranged  in  the  form  of  a 
cross,  also  often  separate.  '*  The  small 
individuals,  probably  the  yomig,  were 
of  a  clear  yellow  hue.  I  could  not  ob- 
serve the  slightest  motion  in  them." 
— On  the  Animalcules  of  the  Red  Suow, 
Bibliotheque  Univ.  de  Geneve,  May  1841. 


OF  THE  VOLVOCJNA. 


5i: 


Genus  PANDOEINA  (XIX.  59-69)  (Part  I.  p.  157).— Destitute  of  eye- 
speck  and  tail,  but  provided  with  a  globular  lorica  and  a  slender  filament. 
During  self- division  the  creature  acquires  the  appearance  of  a  mulberry. 
Transparent  vesicles  occur  in  one  species :  two  exhibit  green,  and  a  third 
colourless  granules. 

Dujardin  esteems  the  presence  of  the  red  speck  to  be  insufficient  to  distin- 
guish Eudorina  as  a  genus  distinct  from  Pandorlna  -,  and  most  recent  observers 
agree  with  him. 

It  has  been  shown  by  Braim  {Rejuvenescence,  Ray  Soc.  1853,  pp.  169-209), 
as  well  as  by  others,  that  Ehrenberg  was  in  error  in  assigning  a  single  fila- 
ment only  to  Pandorina,  and  no  eye-speck — since  two  flabella  extend  from 
the  more  pointed  extremity  of  the  being,  and  close  to  their  base  is  a  brownish- 
red  speck. 

Prof.  Henfrey  details  {M.  T.  1856,  p.  49)  the  characteristics  of  Pandorina 
much  more  fully,  and  corrects  the  errors  into  which  Ehrenberg  fell.  He 
assumes  it  to  be  a  plant,  and  thus  describes  it : — "  Pandorina. — Frond  a  mi- 
croscopic, elhpsoidal,  gelatinous  mass,  containing,  imbedded  near  the  peri- 
phery, sixteen  or  more  biciliated,  permanently  active  gonidia,  arranged  in 
several  circles  perpendicular  to  the  long  axis  of  the  frond.  The  gonidia,  al- 
most globose,  with  a  short  beak-hke  process,  a  red  spot,  and  a  pair  of  cilia 
which  project  through  the  substance  of  the  frond  to  form  locomotive  organs 
upon  its  surface.  Reproduction :  1.  By  the  conversion  of  each  gonidium 
into  a  new  frond  within  the  parent  mass.  2.  By  the  conversion  of  the  go- 
nidia into  encysted  resting  spores,  which  are  set  free,  and  (?)  subsequently 
germinate  to  produce  new  fronds."  The  genus  more  closely  resembles  Ste- 
l^lianosplioera  than  any  other  of  the  family. 


Pandobina  Moriim  (Volvox  Morum, 
M.)  (xix.  59-69). — Body  simple  or  mul- 
tipartite, enclosed  within  a  simple  lorica. 
Colom*  green  ;  filament  twice  as  long  as 
the  body.  In  water  with  Lemnse  and 
Confervae.  Size  of  individual  1-1150", 
cluster  1-120".  Some  individuals  broken 
from  the  cluster  by  Ehrenberg  have  not 
been  above  one-third  the  former  mea- 
surement. 

P.  Morum  is  much  more  satisfactorily 
and  correctly  described  by  Mr.  Henfrey, 
thus  :  —  "  Fronds  hyaline,  from  about 
1-80"  downwards.  Gonidia  either  16, 
and  then  aiTanged  into  cireles  of  4;  or  32, 


and  then  in  5  circles — 2  at  the  poles,  of 
4,  and  the  intennediate  3  of  8  gonidia; 
which,  in  the  perfect  form,  stand  near 
the  periphery,  and  wide  apart.  In  the 
forms  which  produce  the  resting-spores, 
the  gonidia  are  crowded  together  in  the 
centre.  The  gonidia  are  green ;  but  the 
contents  of  the  resting-spores,  after  they 
have  become  encysted,  are  converted 
into  oily  and  granular  matter  of  a  bright 
red  colour." 

P.  hi/alincL — Form  globular.  In  the 
Nile  with  Confervte,  and  is  a  doubtful 
species.     1-5760". 


Genus  GONIUM  (XIX.  32-37;  Part  I.  p.  152).— Deficient  both  of  eye- 
speck  and  tail ;  lorica  simple ;  in  the  process  of  self-division,  form  regular  four- 
cornered  tablets  or  plates.  The  lorica  (a  lacerna)  of  each  individual  (as  is  seen 
after  its  separation)  is  nearly  round ;  and  the  organism  can  cast  it  off  and  form 
it  anew.  In  one  of  the  species  (6r.  Pectorale),  two  vibratory  filaments  are 
placed  at  the  mouth  as  organs  of  locomotion,  &c. ;  in  the  other  species  these 
have  not  been  observed.  Vacuoles  are  seen  within  G.  Pectorale  ;  and  a  red 
speck  (produced  probably  by  refracted  light)  at  the  base  of  the  filaments  has 
been  conceived  by  Ehrenberg  to  indicate  the  mouth. 

Cohn's  elaborate  account  furnishes  the  follovving  additional  notes  on  Go- 
nium  {Eiitwick.  p.  179  ;  and  Part  I.  p.  152)  : — The  quadrate  tablets  consist  of 
sixteen  polygonal  (mostly  hexagonal)  cells,  united  together  by  tubular  prolon- 
gations from  their  angles,  the  whole  being  siuTOimded  by  a  common  gelatinous 


518 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


investment  (the  envelope-cell).  Each  cell  or  gonidiiim  has  its  own  hyah'ne 
membrane,  is  somewhat  elongated  into  a  neck-like  form  on  one  side,  and  con- 
tains a  homogeneons  protoplasm,  chlorophyll,  and  dark  granules  (except  in  the 
neck-hke  portion),  and  in  the  centre  a  single  chlorophyll  vesicle ;  besides  these, 
several  vesicular  spaces,  and  one,  two,  or  rarely  three  contractile  vesicles. 
From  the  pointed  end  two  filaments  proceed,  and  pierce  the  common  envelope, 
to  vibrate  freely  on  the  outside  of  the  tablet.  Reproduction  by  fission  is  not 
a  simultaneous  act,  as  represented  by  Ehrenberg,  but  is  effected  by  repeated 
divisions  through  four  generations  or  series,  in  each  of  which  the  '  daughter 
cells'  severally  resolve  themselves  into  two  others,  as  happens  in  all  the  Yol- 
vocina  andPalmelleae.  The  result  of  this  act  of  reproduction,  when  uninterfered 
with  and  complete,  is  the  fonnation  of  sixteen  tablets  similar  to  the  parent, 
but  without  any  organic  connexion,  each  yoimg  tablet,  however,  being  enclosed 
within  the  wall  of  the  parent  cell,  out  of  which  it  has  been  produced,  for  this 
cell-wall  takes  no  part  in  the  process  of  fission.  Sometimes  a  tablet  breaks 
up,  setting  its  component  gonidia  free,  when,  their  angular  processes  becoming 
absorbed,  and  their  membrane  further  removed  from  the  contents,  they  as- 
simie  the  general  aspect  of  a  Chlami/dococcus  or  Chlamydomonas,  and  probably 
enter  on  a  resting-stage  like  the  gonidia  of  Stephanosphcera.  Ehrenberg  be- 
lieved the  isolated  cells  to  be  reproduced  by  fission  like  those  united  in  the 
tablets ;  but  Cohn  never  observed  this  take  place.  If  this  resting-stage  actually 
occurs,  then  Gonium  is  projpagated  by  '  macrogonida' ;  but  of '  microgonidia'  no 
evidence  has  been  discovered.  The  tablets  revolve  on  their  shorter  axis,  and 
hence,  on  a  polar  aspect,  appear  lilte  a  disk,  on  an  equatorial  like  a  line  of 
cells.  A  peculiar  structural  relation  obtains  between  Oonkmi  and  Pedias- 
trum.  Lastly,  Cohn  asserts  that  Gonium  Pectorcde  is  the  only  true  species  of 
this  genus ;  that  the  others  enumerated  by  Ehrenberg  are  motionless,  and 
belong  to  the  genus  Merismopedia  among  the  Palmellaceae. 


Gonium  Pectorale  (M.)  (see  p.  152). 
— Consists  of  sixteen  spherical  bodies 
enclosed  within  a  transparent  lorica,  and 
disposed  regularly  in  a  quadrangular 
form,  and  in  the  same  plane,  like  the 
jewels  in  the  breast-plate  of  the  Jewish 
High  Priest,  whence  the  specific  name. 
The  four  central  ones  are  generally  larger 
than  those  which  surround  them;  and  the 
combined  diameters  of  the  three  smaller 
balls  are  about  equal  to  the  two  larger 
centre  ones  to  which  they  are  attached ; 
the  external  corners  are  consequently 
vacant.  As  these  animalcules  swim  and 
revolve  in  the  water,  they  occasionally 
present  a  side  view  to  the  observer,  when 
the  circimiference  of  the  larger  central 
globides  may  be  seen  projecting  beyond 
the  others.  Sometimes  the  clusters  ap- 
pear irregular.  They  are  of  a  beautiful 
transparent  green  colour ;  and  in  swim- 
ming, the  globules  often  appear  of  an 
ellipsoidal  figure. 

In  order  to  observe  the  structure  of 
tliis  highly  curious  and  beautiful  crea- 
tm'c,  considerable  adroitness  is  necessary 
in  the  management  of  the  microscope; 
while  a  little  indigo  conveyed  into  the 
water  with  the  point  of  a  cameFs-hair 


pencil  wUl  be  required  to  see  the  whorls 
and  currents  set  in  motion  around  it. 

The  single  animalcules  (xrx.  33)  swim 
like  the  Monads,  in  the  direction  of  the 
longitudinal  axis  of  their  bodies ;  but  the 
tablets  have  a  variety  of  movements: 
sometimes  they  move  quite  horizontally, 
at  others  vertically,  at  others  again  on 
their  edge,  revolving  like  a  wheel.  A 
magnifying  power  of  200  diameters  is 
sufficient  for  general  examination ;  but 
to  exhibit  aU  the  structm-es  shown  ia 
the  engravings,  fom'  times  that  power 
will  be  required.  In  clear  water,  salt 
and  fresh,  near  the  surface.  Discovered 
by  Miiller  in  clear  water  at  Copenha- 
gen, 1773.  Size  of  animalcide  from 
1-460"  to  1-1150",  of  tablet  not  exceed- 
ing 1-280". 

G.  jmnctatimi.  —  Corpuscles  green, 
spotted  Avith  black,  and  enclosed  within 
a  crvstalline  lorica.  Amongst  Confervas. 
1-4600";  a  tablet  of  16, 1-570"  in  breadth. 

G.  tranquillum.  —  Corpuscles  green, 
within  a  crystalline  lorica,  each  1-2880"; 
a  tablet  of  16  corpuscles,  from  1-140"  to 
1-220"  in  breadth.  Tablet  sometimes 
tAvice  as  broad  as  long. 

G.  hyakmwi. — Corpuscles  transparent, 


OF  THE  VOLVOCINA. 


519 


within  a  crystalline  envelope.     In  stag-  The  number  of  animalcules  in  the  tablets 

nant  water.    Corpuscles  1-3000" ;  tablet  varies  from  four  to  sixty-four.     In  sea- 

of  20  to  25,  1-600"  in  breadth.  water.     Size  1-5000"  ;    tablet  1-500"  in 

G.     f/lancum.  —  Corpuscles      bluish-  diameter, 
green,  within   a    crystalline    envelope. 

Gonium  tmnquUhim  and  G.  glaucum,  says  Perty,  are  Algae  (/.  e.  he  would 
say,  are  not  members  of  this  genus).     He  adds  as  a  new  species, 


G.  helvetieum.  —  The  green,  spherical 
corpuscles  combined  in  a  tabular,  gela- 
tinous envelope,  without  any  intercom- 
mmiicating  bands,  each  furnished  with 
a  fine  red  stig-ma  and  two  ciliary  loco- 
motive filaments.  On  a  polar  view,  one 
large  roimd  vesicle  is  -visible ;  on  the 
lateral  aspect,  two  such  are  apparent, 
one  larger  than  the  other.    On  drying 


the  specimen,  the  stigma  itself  assumes 
the  fomi  of  a  vesicle.  It  is  readily  dis- 
tinguished from  G.  quaclrcmgulatam  by 
the  absence  of  the  connecting  bands  or 
tubules  between  the  several  corpuscles 
in  the  tablet.  Diameter  of  tablet  1-360", 
of  coi'puscles  1-1300".  Filaments  2^ 
times  longer  than  the  gonidia.  In  ponds 
about  Bern. 

Genus  SYNCRYPTA  (XX.  26-28).— This  genus  is  mainly  characterized 
by  secreting  or  hiding  itself  (as  the  name  implies)  within  a  second  envelope. 
Each  individual  is  provided  with  a  special  lorica  of  the  form  of  a  little  shield 
(scuteUum),  and  is  united  with  others  m  a  common  gelatinous  envelope  (la- 
ceriui)  into  which  it  can  retreat ;  neither  eye-speck  nor  tail  is  present,  but 
there  is  a  large  filament ;  self- division  longitudinal.  The  filaments  of  the 
several  corpuscles  give  the  cluster  an  appearance  of  being  surrounded  with 
hairs. 

With  this  genus  Dujardin  would  identify  his  Cryptomonas  (Tetrahcena). 
The  very  doubtful  position  and  independence  of  tliis  genus  as  a  member  of 
the  Yolvocina  have  been  remarked  on  in  the  general  notes  on  this  family 
(p.  144).  Mr.  Carter,  iii  a  paper  lately  published  (A.  N.  H.,  1859,  iii.  p.  1  et 
seq.),  represents  Sijncry]pta  to  be  the  "  spermatic  form  "  of  Volvox  or  of  Sj^hce- 
rosira  (Ehr.).    (See  notes  on  Sph^eoslra.) 


This  berry-like  cluster  of  animalcules, 
when  rolling  through  the  water,  is  a 
beautiful  object  for  the  microscope;  and 
with  the  aid  of  a  little  indigo,  the  nu- 
merous currents  it  creates  are  readily 
perceived :  xx.  27.  magnified  260  dia 
meters ;  fig.  26.  400  ;  an(^ 
about  to  sever  into  four, 


fig.  28  a  cluster 


SiTNCRYPTA  tolvox  (xx.  26-28).  — 
Form  oval ;  colom*  green,  with  w^hitish 
rays  in  the  centre.  Generally  in  water 
drained  fi'om  Confervae.  1-2880";  a  clus- 
tered globule  in  its  crystalline  tunic, 
hardly  exceeding  1-570".  Fresenius 
states  that  he  has  seen  a  red  stigma  in 
each  corpuscle,  which  was  overlooked  by 
Ehrenberg. 

Genus  SYNUHA  (XX.  29,  30). — Eye-speck  absent ;  tail  filiform,  attached 
either  to  the  base  of  its  own  lorica  or  to  the  centre  of  the  cluster  to  which  it 
belongs.  The  general  envelope  is  spherical,  gelatinous,  and  is  hollowed  out 
by  as  many  compartments  or  cells  as  there  are  individuals  in  the  little  com- 
munity. From  out  of  these  cells  they  can  stretch  themselves  a  considerable 
distance,  whilst  they  continue  attached  by  the  extremely  delicate  and  exten- 
sible tan.  This  so-caUed  tail  or  pedicle  is  homologous  with  the  connecting 
rays  or  threads  of  the  several  corpuscles  in  the  globe  of  Volvocc,  and  is,  like 
them,  a  production  of  the  protoplasm  of  the  interior.  As  before  remarked, 
this  genus  is  doubtfully  retained ;  for  the  chief  distinctive  feature  Ehrenberg 
insists  on,  viz.  the  presence  of  a  double  lorica,  loses  its  significance  now  that 
modem  researches  have  shown  that  the  formation  of  a  second  or  common  en- 
velope is  an  ordinary  phenomenon  at  a  certain  stage  of  existence  of  most  or 
of  aU  A^olvocina.  Moreover,  the  description  given  of  this  genus  is  too  loose 
and  faulty,  and  its  accompanying  illustrations  too  rude,  to  render  it  possible 


520 


SYSTEMATIC  HISTOEY  OF  THE  INFFSOKIA. 


to  rightly  appreciate  its  characters  and  to  assign  it  its  proper  place,  even  if 
it  is  admitted  to  he  an  independent  organism.  Mr.  Carter  has  lately  piih- 
lished  (A.  N.  H.  1859,  iii.  p.  10)  the  opinion  that  Synura  is  the  "  spermatic 
form"  of  Volvox  or  of  Sj^hcerosira.     (See  notes  on  Sphl^eosiea). 


Synura  uvella. — Corpuscles  oblong, 
yellow,  capable  of  extending  themselves 
iko  three  times  their  usual  length,  by 
means  of  the  extensile  tail.  The  cluster 
has  the  form  of  a  mulbeny,  and  its  mo- 
tion is  rolling  like  that  of  Volvox  Gloha- 
tor.     XX.  29,  XX.  30,  show  a  portion  of 


a  cluster,  and  the  manner  in  which  the 
tails  are  inserted  in  the  common  enve- 
lope. This  species,  along  with  Si/ncrypta 
and  TJroglena  Volvox^  may  have  often 
been  confounded  -^dth  TJveJla  virescens. 
Length,  exclusive  of  tail,  1-700"  ;  dia- 
meter of  cluster  from  1-190"  to  1-280". 


Genus  UROGLENA  (XX.  31).— The  members  of  this  genus,  unlike  other 
Volvocina,  possess  both  an  eye-speck  and  tail ;  they  live  in  clusters  under  a 
common  envelope  (lacerna),  which  is  subdivided  into  cells  for  the  accommo- 
dation of  the  several  individuals.  Self-division  takes  place  simply  and  equally 
in  these  individuals,  whilst  in  their  clustering  condition.  They  are  placed  at 
uniform  distances  from  each  other,  attached  by  their  tails,  which  radiate  from 
the  centre.  Each  monad  is  furnished  with  a  filament,  which  projects  ex- 
ternally and  gives  to  the  entire  group  the  appearance  of  being  covered  with 
hairs.  When  the  creatures  divide,  the  mantle  or  lacerna  enlarges  only,  and 
does  not  itself  undergo  fission.  The  red  speck  is  in  the  fore  j)art  of  the  body  ; 
the  tail  is  filiform,  resembling  that  of  Vorticella  and  Bodo. 

The  tail  mentioned  in  the  above  description  is  the  same  as  that  of  Synura  : 
the  use  of  the  term  is  very  inappropriate  in  both  cases.  It  may  be  that 
Uroglena  should  be  united  with  Synura  as  Dujardin  proposed,  since  the 
presence  of  an  eye-speck  in  the  former  and  its  absence  in  the  latter  is  not 
distinctive;  still  we  know  too  little  of  the  being  which  Ehrenberg  would 
call  a  Uroglena,  to  come  to  a  decision  respecting  its  affinities  and  generic 
independence. 

This  genus  is  another  which  Mr.  Carter  would  set  aside,  as  he  considers  it 
(A.  N.  H.  1859,  iii.  p.  10)  the  same  with  Sphcerosira,  or  the  "  spermatic 
form  "  of  Volvooo.     (See  notes  on  Sph^rosiea.) 


Uroglena  Volvox  (xx.  31). — Cor- 
puscles yellow,  oblong ;  tail  extensible, 
from  three  to  six  times  the  length  of  the 
body,  and  even  more ;  cluster  mulberry- 
shaped.  There  is  little  doubt  that  single 
corpuscles  of  this  genus  have  often 
been  taken  for  creatm'es  of  a  different 


family.  Ehrenberg  states  that  he  has 
observed  indi\dduals  with  two  or  three 
colom'ed  specks,  which  he  conceives  to 
have  been  a  symptom  of  approaching 
self-division.  In  tm-f  Tvater.  Diam.  ot 
cluster  1-90". 


Genus  EUDORINA. — Has  no  tail,  but  possesses  a  distinct  eye-speck,  and 
a  simple  \ibratory  filament  anteriorly.  Self- division  proceeds  simply  and 
equally,  whilst  the  corpuscles  retain  their  clustered  condition.  They  are 
periodically  able  to  cast  off  their  globular  envelope  (lacerna),  and  to  exude  a 
new  one,  like  certain  Annelida.  To  observe  the  eye-speck,  a  power  of  300 
diameters  must  be  skilfully  employed. 

Dujardin 's  proposition  to  combine  Eudorina  with  Pandorina  has  been 
already  mentioned  (p.  515),  and  appears  to  be  a  correct  one.  The  assigned 
characteristic  difference  between  those  two  genera  is  worthless;  for Pandoiiiia, 
like  Eudorina,  has  a  coloured  speck  (see  p.  157  et  seq.). 


Eudorina  elegans. — Corpuscles  green, 
globular, never  protruding  fi^om  their  cells 
beyond  the  common  envelope.  Stigma 
sparkling  red.  The  clusters,  which  are 
of  an  oval  or   globular  form,    contain 


generally  from  30  to  50  individuals,  and 
never  less  than  15.  Motion  revolving. 
Fig.  47  exhibits  the  filaments  extended, 
and  the  bodies  of  the  animalcules  within 
the  lacerna   (i.  e.   the   "  common   enve- 


OF  THE  TOLYOCINA.  521 


lope").  Clusters  of  these  beautiful  ani- 
malcules are  often  seen  in  such  amazing 
numbers,  along  with  the  Vohox  Glohator 


tempted  to  retain  them  in  large  quanti- 
ties, the  second  day  wall  generally  ex- 
hibit a  thick  mass  of  dead  ones  at  the 


and  Chlamydomonas  Pulvisculus,  as  to  j  bottom  of  the  vessel.  When  a  few 
render  the  water  (otherwise  colourless)  ;  only  remain  alive,  if  the  stale  water 
of  a  decided  green  colom*,  especially  j  be  pom-ed  away,  and  they  are  removed 
towards  its  edges.  They  are  exceed-  ■  into  a  vessel  of  clear  water,  they  will 
ingly  delicate — so  much  so  that  it  is  j  live  for  weeks.  At  Hackney  and  Hamp- 
ditficult  to  preserve  them  alive  for  more  stead ;  most  abimdant  in  the  spring  of 
than  a  day  or  two  :  whenever  it  is  at-  '  the  year.     Diam.  of  cluster  1-180". 

Genus  CHLAMYDOMONAS  (XYIII.  40,  51-54;  XIX.  16)  (Part  T. 
p.  146). — Tail  absent,  eye-speck  distinct  red,  filament  double ;  multiplication 
takes  i^laee  by  self- division  within  the  common  envelope,  which  is  ruptui-ed 
to  give  the  products  liberty.     The  lorica  indistinct  in  young  beings. 

Braun  {On  Rejuvenescence,  Ray  Soc.  1853,  p.  158)  appears  to  elevate  this 
genus,  in  union  with  Chlamydococcus  and  Gloeococciis,  to  the  rank  of  a  family 
parallel  mth  the  Yolvocina,  under  the  name  of  ChJamydomonada.  Indeed, 
although,  as  Cohn  has  weU  shown,  these  genera  agree  in  aU  essential  particu- 
lars and  relations  with  the  Yolvocina,  yet  the  existence  of  each  gonidium 
as  an  independent  being  contrasts  so  strongly  mth  the  aggregate  condition 
of  the  rest  of  the  Yolvocina,  that  there  seems  sufficient  ground  to  group  them 
as  a  sub-family.  In  order,  therefore,  to  retain  the  Chlamydomonada  toge- 
ther, we  shall  depart  from  our  usual  custom,  by  inserting  the  new  genera 
Chlamydococcus  and  Gloeococcus  after  Chlamydomonas.  Chlamydomonas  was 
erroneously  transferred,  as  before  noticed,  by  Dujardin  to  the  Thecamonadina, 
and  renamed  Diselmis.  Its  characters  are  thus  discussed  by  Braun  (oj).  cit. 
pp.  214, 215) : — "  CJiJamydomonas  is  distinguished  from  the  genus  Chlamydo- 
coccus by  the  closely  applied  membrane  of  the  old  swarming-ceUs,  also  by  the 
absence  of  the  little  starch-vesicles  ui  the  interior,  while,  however,  as  is 
usual  in  most  of  the  Palmellaceae,  a  single  large  chlorophyll  utricle  exists  in 
the  iaterior.  There  is  no  central  red  nucleus,  as  in  the  gonidia  of  CJdamy- 
dococcus  ;  but  some  species  have  a  parietal  red  spot.  Motion  is  effected 
by  two  cilia,  as  in  Chlamydococcus.  As  in  that  genus,  there  is  a  growth  of 
the  gonidia  during  swarming,  which  lasts  over  the  day  and  night.  There  is 
also  a  formation  of  microgonidia,"  and  a  resting-stage  m  which  the  colour 
changes  from  green  to  yellowish  red,  or  to  red. 


Chlamydomonas  Pukiscidus  {Manas 
Pidviscuhis,  M.)(xix.  16). — Colour  green ; 
lorica  oval ;  eye-speck  brilliant  red ;  fila- 
ment double.  (See  Diselmis  viridis, 
p. 512.)  Cohn  identifies  it  -with  Pol ytoma 
Uvella. 

These  creatures  form  a  large  portion 
of  the  gTeen  matter  which  colom-s  the 
water  contained  in  water-butts,  ponds 
and  puddles  in  the  summer  and  autumn, 
and  especially  after  a  storm.  They  will 
rarely  fail  to  be  obseiwed  when  any  of 


this  gTeen  water  is  examined  imder  the 
microscope.  Whenever  these  creatures 
exist  in  large  quantities,  midtitudes  of 
them  and  of  their  envelopes  rise  to  the 
surface  of  the  water,  and  form  a  gi-een 
stratmn  upon  it.  Although  this  film 
somewhat  resembles  one  of  Ulvaceae,  yet 
it  is  easUy  distinguishable  by  its  com- 
position of  living  coi*puscles  with  red 
specks,  connected  together  by  a  loose 
mucous  tissue,  formed  of  dead  speci- 
mens and  empty  loricae.     1-550". 


Kiitzing  affirmed  that  this  species  was  merely  a  phase  of  Stygcoclinium,  into 
the  filaments  of  which  it  became  transformed  by  an  act  of  germination.  This 
opinion  has  not  been  accepted,  as  it  is  supposed  that  Kiitzuig  confounded  the 
spores  of  that  Alga  vdih.  the  gonidia  of  Chlamydomonas  Pidviscidus. 

Among  the  additional  species  of  Chlamydomonas,  those  forms  described  by 
Dujardin  as  members  of  Diselmis  (p.  512)  should  probably  take  their  place 


522 


SYSTEMATIC  HISTORY  OP  THE  INFUSOBIA. 


here.  Braun  describes  the  following  new  species,  premising  the  remark  that 
<'  the  species  are  doubtless  very  numerous,  but  the  distinction  of  them  from 
one  another,  as  well  as  from  the  swarming  cells  of  many  other  Algae,  is 
very  difficult  mthout  a  complete  acquaintance  with  the  history  of  their 
existence." 


C.  obtusa(BvBnrL). — Colour  dark  green; 
truncate  at  both  ends,  and  oblong,  chang- 
ing to  spherical  and  a  yellowish  brown, 
and  at  length  a  red  coloiu:  on  assiuning 
the  resting-stage.  ''The  macrogonidia 
grow  during  swarming,  from  l-60th  to 
almost  l-30th  of  a  millimetre  long ;  they 
are  longish,  of  equal  diameter  on  both 
sides,  and  veiy  obtuse,  almost  trimcated, 
haying  a  colomiess  space  at  the  ciliated 
extremity,  presenting  the  form  of  a  notch. 
The  contents  are  dark  green,  finely 
granular,  with  a  large  vesicle  at  the  pos- 
terior extremity,  a  roundish  lighter 
space  m  front  of  this,  and  no  red  point. 
They  multiply  by  simple  or  double 
hahing  in  several  successive  genera- 
tions. Sometimes  a  further  continua- 
tion of  the  division  of  the  full-grown 
macrogonidia  occm's,  forming  16  or  32 
macrogonidia  from  l-200th  to  l-120th 
millimetre  long,  of  ovate  shape  and 
lighter  colom*,  tending  towards  brownish- 
yellow.  The  resting  (seed-)  cells  are 
globidar,  about  l-40th  millimetre  in  dia- 
meter, at  first  green,  subsequently  light 
yellowish-brown,  finally  flesh-red ;  they 
have  a  tough,  colourless,  and  transpa- 
rent membrane.  In  the  Rhine  valley, 
near  Freibiu'g,  in  pools  in  sand-pits, 
which  are  occasionally  almost  completely 
dried  up  in  summer." 

C.  tingens  (Braun). — Gonidia  smaller 
than  in  the  preceding  species,  1-120  to 
1-60  millim.  long,  ovate,  lighter  green, 
likewise  destitute  of  a  red  spot;  the 
membrane  is  more  distinct  in  old  age. 
Increase  by  double,  rarely  by  single 
halving  ;  in  the  former  case,  by  decussat- 
ing sections.  Contents  granular,  punctate 
in  appearance,  green,  with  one  large 
vesicle.  In  the  resting-stage  they  ac- 
quire a  pale  reddish  colom* ;  the  vesicle 
becomes  indistinct,  and  the  contents 
coarsely  gi-anular  in  aspect  fi'om  the 
formation  of  oil.  Microgonidia  also  are 
foi-med.  "The  resting-  but  stiU  green 
condition  seemed  to  me  to  correspond 
to  Protococcus  Felisii  (K.),  that  which 
turned  red  through  desiccation,  to  Pr. 
Orsinii."  In  pools  near  Freibm-g.  Cohn 
(Entwick.  pp.  202,  203)  detected  two 
vesicles  in   Chlmnydojnotias,  below  the 


point  of  insertion  of  the  filaments,  very 
slowly  but  rhythmically  contractile,  and 
mentions  a  species  under  the  name  of 
Chlamydomonas  hyalina,  which  he  makes 
S}Tionymous  with  Polytoma  Uvella  (E.), 
and  states  to  differ  from  Ch.  Pulvisculus 
only  by  the  want  of  chlorophyll  and  of 
a  red  speck  (op.  cit.  pp.  140  *fe  l69).  He 
moreover  notes  a  new  form,  probably 
generically  distinct  by  having  not  a 
globular  but  a  winged  prismatic  figiu-e, 
quadrangular  on  a  transverse  section, 
with  the  two  wings  like  two  outstretched 
points,  although  in  other  respects  agree- 
ing with  Chlamydomonas  Pulvisculus, 
Perty  (p.  85)  objects  to  making  Chla- 
mydomomis  a  genus  of  Volvocina,  and 
refers  it  instead  to  the  so-called  "Spo- 
rozoidia."  He  fm*ther  tells  us  that  Chi. 
Pulvkc'ulus  (E.)  is  rare  about  Bern,  but 
there  is  a  smaller  form  very  common, 
which  he  proposes  to  call 

C.  communis  (Perty). — He  finds  also, 
but  less  frequently,  a  more  globular 
variety,  which  appears  to  be  the  Tra- 
chelomonas  eniarginata  (Eichwald),  but 
is  in^  fact  a  Chlamydomonas,  which  he 
names 

C.  glohulosa  (Perty).  —  His  species 
Hysginum  pluviale  ^and  H.  nivale  (i.  e. 
Chlamydococcus)  he  suggests  uniting, 
with  the  species  of  Chlamydomonas,  into 
a  group  (of  Sporozoidia)  imder  the  name 
of  Schizonema. 

C.  midtijilis  (Fresenius"). — Round  or 
oval ;  a  distinct  nucleus  m  the  centre ; 
granidar  contents  green ;  filaments  four, 
longer  than  the  cell ;  at  their  base  a  rose- 
colom-ed  contractile  vesicle,  and  poste- 
riorly to  this  a  red  stigma.  Lorica  thin, 
closely  investing  contents.  As  many  as 
six  filaments  seen  in  some  larger  speci- 
mens.   1-92'"  to  1-63'".    In  fresh  water. 

C.  hyalina  (Cohn,  Fresenius). — Elon- 
gated elliptical ;  roimded  at  both  ends ; 
filaments  two,  longer  than  the  body; 
posterior  half  of  cavity  occupied  by  gra- 
nides ;  a  clear  non-contractile  space  in 
the  centre  ;  a  small  contractile  sac  at  the 
base  of  the  filaments.  1-66'"  to  1-46'". 
In  ponds  coloured  by  EuglencB. 

It  is  doubtftilly  separable  fi'om  Chi. 
Pulvisculus. 


Genus  CHLAMYDOCOCCUS  (Part  I.  p.  148)  (XIX.  20-31).— Gonidia 


OF  THE  YOLVOCINA.  523 

spherical;  coloiu'  green  or  red,  enclosed  by  a  hyaline  structureless  mem- 
brane, removed  some  distance  from  the  coloured  contents  by  a  clear  interspace 
or  areola.  The  central  protoplasm,  coloiu'ed  by  chlorophyll  or  a  red  oil,  and 
having  one  or  more  chlorophyll  utricles  at  the  centre,  has  its  spherical  figui^e 
destroyed  by  an  elongation  at  one  part  into  a  tapering  process,  from  which 
two  filaments  proceed,  and,  after  perforating  the  external  "  envelope  cell," 
protrude  as  motile  vibratile  organs.  The  inner,  coloured  globule  has  no 
special  membrane,  and  in  consequence  imdergoes  multiform  transformations 
of  its  outline  in  the  com^se  of  development.  In  the  resting-stage  the  enclosed 
coloured  mass,  the  '*  primordial  cell,"  secretes  over  its  siuface,  inside  its  enve- 
lope cell,  a  new,  tough,  cellulose  membrane,  whilst  the  envelope  cell  is  dissolved 
into  a  mucous  layer.  In  such  still  cells  macrogonidia  are  produced  by  fission  of 
the  contents,  in  the  power  of  two,  and  after  a  time  burst  through  the  parent  cell, 
develope  their  two  ciliary  ^filaments,  and  proceed  to  develope  a  cellulose  mem- 
brane over  their  entire  sui'face,  which  becomes  further  and  further  removed 
until  they  acquii'e  the  characters  of  the  ordinary  moving  cells.  When  divi- 
sion is  more  frequently  repeated,  microgonidia  are  formed,  which  move  much 
more  actively,  and  do  not  secrete  an  envelope  cell ;  they  are  incapable  of 
propagation,  and  pass  immediately  into  the  condition  of  rest.  The  motionless 
celU  of  Clilamydococcus  are  of  much  simpler  structui^e  than  the  motile,  and 
consist  simply  of  a  tough,  spherical,  cellulose  membrane,  and  green  or  red 
contents,  organized  as  a  primordial  utricle.  Vacuoles  are  found  among  the 
contents  of  Chlamydococcus-ceUB ;  but  a  contractile  vesicle  has  escaped  observ- 
ation. Chlami/dococcus  and  the  two  allied  genera,  Glceococcus  and  Chlamydo- 
monas,  differ  from  the  true  Yolvocineas  in  this  respect :  viz.  they  separate  from 
each  other  after  complete  fission,  as  primordial  utricles,  and  then  severally  pro- 
ceed to  form  an  independent  envelope  cell ;  whilst  the  rest  of  the  Volvocinese 
continue,  on  theii'  production  by  fission,  to  live  in  groups  and  produce  around 
their  aggregated  mass  an  envelope  cell  in  common.  It  bears  the  same  rela- 
tion, therefore,  to  the  rest  of  the  Yolvocineae  that  Pleurococcus  does  to  Palmella, 
Cijclotella  to  Meloseim,  or  Vorticella  to  Ejnstylis.  Cldamydococcus  is  distin- 
guished from  the  moving  germs  (sporozoids)  by  which  the  greater  nimiber  of 
Algae  propagate,  both  by  a  somewhat  more  complex  structui'e,  and  by  the 
circumstance  that  the  motion  lasts  for  a  very  long  time,  and,  finally,  by  the 
power  of  the  moving  cells  to  propagate  as  such,  without  entering  into  the 
state  of  rest  otherwise  than  as  quite  a  temporary  condition.  Perty,  who  has 
studied  this  genus  veiy  minutely,  employs  the  term  Hysgimim  to  designate 
it,  although  it  had  previously  received  other  names  from  other  observers, 
besides  that  we  have  employed.  Indeed,  o^ving  to  the  various  appellations 
given,  and  especially  the  specific  names  invented  for  the  multiform  varieties 
of  the  same  organism,  the  synonyms  became  very  perplexing  and  a  positive 
impediment  to  the  progress  of  our  knowledge  of  this  genus.  Among  the 
multitude  of  proposed  species,  two  only  are  now  accepted,  viz.  Cldamydococcus 
pluv'mlis  and  Chi.  nivalis;  but  their  distinctive  characters  are  nowhere 
detailed  in  a  definite  and  available  form  for  our  purpose.  The  red  snow  of 
Alpine  regions  is  the  red  variety  of  both  these  species.  The  other  varieties  of 
Chlamydococcus  have  been  more  widely  described  under  the  title  of  Proto- 
coccus,  and  those  of  a  red  colour  under  that  of  Hcematococcus.  Cohn  cites 
two  principal  synonyms  for  Chi.  pluvudis,  viz.  Hcematococcus  pluvkdis  and 
Chlamydococcus  versatUis,  and  in  his  Monograph  on  this  organism  employs 
the  term  Protococcus  pluvudis,  although  in  a  subsequent  contribution  he 
adopts  Braim's  designation  as  employed  by  us.  The  many  modifications  of 
form  of  this  one  species  under  different  circumstances  of  development  and 
habitat   have  received  as  many  diff'erent  names,  from  the  notion  of  their 


524 


SYSTEMATIC  HISTOET  OF  THE  ESTFUSORIA. 


being  specifically  distinct.  These  Cohn  has  pointed  out  in  his  essay ;  but  only 
that  portion  of  them  is  worth  citing  which  has  attracted  notice  in  various 
works.  "  Thus  the  still  Protococcus-ce\l  corresponds  to  the  P.  Coccoma  (Kiitz.) : 
when  the  border  becomes  gelatinous,  it  resembles  P.  pidcJier,  and  the  small 
cells  P.  minor.  The  encysted  motile  zoospore,  on  the  other  hand,  is  the  Gyges 
Oranulum,  and  resembles  also  P.  turgidus  (K.)  and  perhaps  P.  versatilis 
(Braun).  The  zoospores  divided  into  two  must  be  regarded  as  a  form  of 
G-yges  hi2ycirtitus,  or  of  P.  dimidiatus.^^  A  red  variety  of  the  cell  was  de- 
scribed by  Girod  Chantrans  as  a  Volvox,  under  the  name  of  Volvox  lacustris ; 
but  Perty  refers  it  to  Hcermatococciis. 

CwLAMYDOCOCCVS  pliwialis. — Sufficiently  characterized  in  the  above  history. 
Chl.  nivalis. — Unsatisfactorily  distinguished. 

Genus  GLCEOCOCCUS. — This  is  a  new  genus  suggested  by  Braun  {On 
Rejuvenescence,  p.  159),  who  thus  describes  it : — "  Ovate,  green  cells,  with  a 
coloiu'less  point,  fi-om  which  a  funnel-shaped,  lighter  space  extends  inwards ; 
a  rather  large  vesicle  also  is  formed  at  the  posterior  extremity.  Multiplica- 
tion by  simple  or  double,  in  the  latter  case  decussating  fission,  after  which 
the  ceUs  remain  loosely  connected  together  by  the  secretion  of  soft,  gela- 
tinous, confluent  coats,  forming  globular  and  finally  amorphous  famihes 
(clusters).  The  cells  of  all  the  generations  succeeding  each  other  dui-ing  the 
formation  of  these  families  (excepting  the  transitory  cells  in  the  case  of 
double  halving)  are  provided  vrith  two  very  long  persistent  cilia,  which  dis- 
appear only  when  division  commences.  The  cells  exhibit  a  feeble  motion 
inside  the  enveloping  and  connecting  jelly,  the  anterior  end  jerking  in  and 
out,  or  suddenly  retracting  a  little.  The  last  generation  of  the  family  leave 
the  gelatinous  mass,  and  swarm  out,  to  settle  down  quickly  in  some  other 
place.  It  is  probable  that  the  formation  of  a  new  family  is  preceded  by  a 
rather  long  state  of  rest — perhaps  there  are  several  resting  generations ;  but 
we  have  no  observation  on  this  point."  A  red  speck  is  not  perceptible.  Two 
species  are  named : — 


G.  minor.  —  Perhaps  specifically  di- 
stinct. Appears  in  the  springs  at  Frei- 
bm-g  eariy  in  the  year,  in  the  form  of 
light-yellowisli-gTeen,  often  pear-shaped 
"  stocks  "  (masses),  almost  as  large  as  a 
hazel  nut,  attached  to  the  sides  of  the 
gutters  of  the  springs,  finally  becoming 
detached,  swimming,  and  shapeless.  The 
cells  are  somi 
millim.  long. 


Glceococcus  7m(cosHS. — The  fidl- 
grown  cells  are  1-60  to  1-50  miUim. 
long :  the  clusters,  forming  at  the  bottom 
of  little  ponds,  attain  the  size  of  an 
apple,  and  are  of  compressed  globular, 
often  lobed-shaped  form  ;  but  at  length 
they  break  up,  and  come  to  the  sm'face  of 
the  water  in  irregular  fragments.  The 
gelatinous  mass  has  a  peculiar  greenish 
spotted  aspect,  which  depends  upon  sub- 
ordinate groups  of  generations  being 
more  closely  packed  together. 

Genus  SPBL^ROSIRA. — Tail-like  process  absent ;  eye-speck  and  fila- 
ment single.  Self-division,  imlike  that  in  the  preceding  genera,  occurs  un- 
equally ^vithin  the  envelope,  and  forms  young  clusters  at  once  from  the  parent 
ones.  This  genus  difi'ers  from  Pandorina  in  having  the  eye-speck,  from 
Eudorina  by  its  unequal  mode  of  self- division,  and  from  Volvox  by  its 
simple  filament.  Self-division  in  these  creatures  takes  place  in  the  longi- 
tudinal direction,  in  parallel  planes ;  so  that  laminse  are  produced,  as  in  the 
case  of  Gonium. 

Splicerosira,  as  heretofore  remarked,  is  regarded  by  Prof.  Busk  as  a  doubtful 
independent  organism ;  he  is,  however,  unable  to  speak  positively  on  this 
point,  and  therefore,  whilst  still  keeping  it  distinct  from  Volvox  Glohcdor,  of 


OF  THE  TOLVOCmA.  525 

which  he  had  some  reason  to  suppose  it  a  peculiar  mode  of  development, 
ranks  it  as  only  a  species  of  Volvox,  instead  of  elevating  it  to  the  rank  of  a 
genus,  and  calls  it  Volvox  Splicerosira.  Dujardin  also  denied  the  distinction 
drawn  by  Ehrenberg  between  Sj^harosira  and  Volvox,  but  did  so  from  mis- 
taken views ;  for  he  re^^resented  Volvox  to  have  only  a  single  filament,  whereas 
both  this  and  Spluerosim  have  two.  ''  It  presents  the  appearance,"  says 
Mr.  Busk  {M.  T.  1852,  p.  33),  ''  of  a  transparent  globe,  set  with  green  spots, 
but  it  differs  from  the  ordinary  varieties  of  Volvox  Glohator  in  two  important 
respects :  1,  in  the  absence  of  any  internal  globules  or  embryos ;  2,  in  the 
irregular  size  of  the  green  granules  lining  the  wall  which,  instead  of  being  of 
uniform  size,  are  of  various  dimensions.  The  difPerent- sized  granules  are 
irregularly  disposed,  although,  in  relation  to  the  sphere  itself,  they,  or  rather 
the  centres  of  them,  are  as  regularly  distributed  as  in  the  three  just-described 
forms  (of  Volvox).  AMiat  is  rather  remarkable  with  respect  to  this  form  is 
the  cii'cumstance  that  the  larger  granules  are  not  disposed  over  the  whole 
peripheiy  of  the  sphere,  rarely  occupying  more  than  two-thirds  of  it  towards 
one  side."  Again,  he  adds — ''  The  smaller  ones  appear  to  resemble  in  all 
respects  those  of  Volvox  Glohator,  and  each  to  possess  two  cilia,  which  is  im- 
portant, if  true,  because  the  only  distinction  between  Volvox  and  Sj^hcerosira 
in  Ehrenberg's  classification  depends  upon  the  circumstance  that  in  Splice- 
rosira there  is  only  one  cilium  to  each  zoospore,  whilst  there  are  two  in 
Volvox. 

*'  My  supposition  that  S.  Volvox  and  V.  Glohator  are  aUied  is  founded,  it 
must  be  owned,  not  upon  any  direct  observation,  but  chiefly  on  the  fact  that 
in  the  water  in  Avhich  the  specimens  of  Volvox  were  contained  there  were  at 
first  none  of  SphcBrosira,  any  more  than  of  V.  aureus,  and  that  after  some 
days  both  were  veiy  numerous.  The  difference  I  am  about  to  describe  in  the 
after- development  of  the  ciliated  zoospores  is  not  by  any  means  a  sufiicient 
ground  upon  which  they  should  be  deemed  distinct  species,  because  much 
greater  differences  are  known  to  exist  in  other  of  the  lower  Algae  during  their 
various  forms  of  development,  without  it  being  thence  allowable  to  suppose  that 
they  are  of  different  species.  In  Volvox  Splicerosira,  then,  as  at  all  events  it 
may  be  termed,  the  larger  green  granules  are  in  fact  the  ciliated  zoospores  in 
a  state  of  fui'ther  progressive  development.  In  the  same  specimen  they  wiU 
be  seen  in  aU  states  of  division  or  segmentation, — fii^st  into  two,  then  into  four, 
and  so  on,  till,  as  in  the  case  of  the  embryo  Volvox,  the  ultimate  result  of  the 
segmentation  constitutes  numerous  minute  ciliated  cells  or  bodies,  not,  how- 
ever, as  in  that  case,  lining  the  inner  surface  of  the  wall  of  a  spherical  case, 
but  forming  by  their  aggregation  a  discoid  body  in  which  the  separate  fusi- 
form cells  are  connected  together  at  one  end,  and  at  the  other  are  free,  and 
furnished  each  with  a  single  cilium.  In  this  stage  their  compoimd  masses 
become  free  and  s^im  about  in  the  water,  constituting,  in  fact,  a  species  of 
the  genus  Uvella,  or  of  Syncrypta  of  Ehrenberg." 

Mr.  Carter  affirms  {A.N.H.  1859,  iii.  p.  4)  that  SiDhcBrosirci  is  not  a  distinct 
genus,  but  the  "  spermatic  form  "  of  Volvox  Glohator,  which  he  describes  as 
one  phase  of  development  of  this  species,  wherein  upwards  of  a  hundred  of 
the  gonidia,  scattered  over  the  periphery  of  the  primary  gemmae  of  the  parent 
globe,  divide  repeatedly  imtil  they  are  broken  up  "  into  128  (?)  linear  ciliated 
segments,  which  are  ultimately  arranged  vertically  upon  the  same  plane,  in  a 
circular  tabular  group,  with  their  cilia  upwards ;  and  when  the  latter  are 
sufficiently  developed,  the  group  oscillates  and  rotates  by  theii^  aid  both  upon 
its  long  and  short  axis.  These  segments  are,  in  fact,  the  spermatozoids, 
each  of  which,  when  they  separate,  is  obseiTed  to  be  linear,  hom-shaped, 
and  colourless  anteriorly  (where  it  is  attenuated),  and  greenish  posteriorly. 


526 


SYSTEMATIC  HISTORY  OF  THE  rS^FUSOfllA. 


provided  ^^dth  a  pair  of  cilia  which  are  attached  to  the  anterior  extremity, 
and  some  distance  behind  them  with  an  eye-spot ;  their  progression  is 
vermicular  from  their  extreme  plasticity,  and  they  keep  up  an  incessant 
flagellating  movement  with  their  ciUa.  As  yet,  I  have  never  seen  any  of 
these  free  in  the  daughter  bearing  the  spermatic  cells  when  the  former  has 
been  outside  the  parent ;  nor  have  I  ever  seen  them  fi^ee  under  any  cir- 
cumstances, except  once,  in  the  old  Volvocc,  when  the  daughter  containing 
the  spermatic  cells  from  which  they  had  been  developed  had  been  partly 
eaten  up  by  Rotatoria. 

"  This  is  the  form  of  Volvocc  Glohator  which  has  been  called  Splia'rosim 
Vohox  by  Ehrenberg ;  and,  like  the  daughters  bearing  the  spore-cells,  it 
becomes  liberated  fi'om  the  parent  before  the  speiinatic  cells  attain  their 
ultimate  development,  that  is,  before  the  groups  of  spermatozoids  become 
separated,  not  before  they  are  formed.  It  is  worthy  of  remark,  too,  that  the 
daughter  bearing  spermatic  cells  is  never  more  than  half  the  size  of  the  spore- 
bearing  daughter,  at  least  as  far  as  my  observations  extend. 

*'  Thus  we  have  the  spore-cells  and  the  spermatic  cells  in  different  daughters ; 
and  as  I  have  never  seen  them  together  in  the  same  daughter,  nor  the 
daughters  respectively  beaiing  them  in  the  same  parent  Volvox,  out  of  some 
scores  of  instances,  I  can  come  to  no  other  conclusion  than  that  the  two 
daughters  meet  after  they  have  left  their  respective  parents,  when,  both  the 
spores  and  the  spermatozoids  having  become  ripe  for  fecundation,  indi^dduals 
forming  the  groups  of  the  latter  separate,  bui'st  from  their  capsules  into  the 
cavity  of  the  daughter,  and  from  thence  find  their  way  out  into  the  water, 
and  then  into  the  cavity  of  the  daughter  bearing  the  spore-cells,  where  they 
become  incorporated  with  the  latter. 

*'  Hence  Volvox  Glohator  would  appear  to  be  dioecious,  and  not  monoecious 
as  stated  by  Cohn ;  and  Sjjhcerosira  Volvox  not,  strictly  speaking,  another 
form  of  Volvox  Glohator,  but  the  spermatic  form.  Cohn,  considering  Volvox 
Glohator  and  Volvox  stellatus  the  same  species,  has  taken  his  fecundating 
character  from  the  spermatic  form  of  the  latter." 

The  spermatic  groups  above  described.  Carter  subsequently  remarks,  con- 
stitute in  all  probability  Ehrenberg's  genera  Syncrypta,  Synura,  and  Uro~ 
glena. 


Sph^eosiea  Volvox.  —  Corpuscles 
pale  gi'een,  of  nearly  a  globular  shape, 
enveloped  in  a  common  mantle.  Eye 
bright  red.  The  cluster  resembles  a 
great  ball  of  coi-puscles,  containing  small 


compressed  clusters  within  it.  Found  in 
considerable  numbers  in  company  with 
Volvox  Glohator,  and  often  attains  its 
size.     Sometimes  found  by  itself. 


Genus  YOLYOX  (XX.  32-47)  (Part  I.  p.  180).— The  genus  Volvox,  which 
is  the  type  of  the  family  Yolvocina,  was  instituted  by  Linnaeus,  and  promul- 
gated to  the  world  in  1 758,  in  the  tenth  edition  of  his '  Systema  Xatm^ae.'  As 
fii*st  described  by  him,  the  two  species  V.  Glohator  and  V.  Chaos  comprehended 
all  known  Infusoria,  excepting  eleven  of  the  tribe  Vorticella,  which  were 
separated  from  them,  under  the  denomiaation  of  Hydra.  In  his  twelfth  edi- 
tion (1766)  of  the  same  work,  he  distributed  the  Infusoria  into  foiu^  genera, 
viz.  Vorticella,  Volvox,  Hydra,  and  Chaos. 

Volvox  is  characterized  by  the  aggregation  of  its  cells  or  gonidia  over  the 
internal  surface  of  a  transparent  lorica  or  common  envelope  ceU,  of  the  form 
of  a  hollow  globe.  Each  corpuscle  or  gonidium  possesses  a  red  speck  and  two 
filaments,  which  protmde  beyond  the  siu-face  of  the  lorica  so  as  to  give  the 
whole  globe  the  appearance  of  being  covered  with  ciha.  The  mode  of 
increasing  by  a  sort  of  internal  gemmation  is  characteristic  of  the  genus. 


OF  THE  VOLTOCrNA, 


527 


Dujardln  was  unable  to  detect  more  than  one  filament ;  but  Ehrenberg's 
description  of  two  is  now  amply  coiToborated. 

The  structui'e  of  Volvox  has  received  the  careful  study  of  many  eminent 
microscopists,  who  have  been  compelled  to  differ  largely  from  Ehrenberg  in 
their  accounts  of  it.  The  resume  given  in  the  general  history  of  Phytozoa 
renders  it  perfectly  unnecessary  to  repeat  in  this  place  the  particulars  of  the 
organization  of  the  members  of  this  genus  or  to  enter  into  the  discussion 
respecting  their  true  nature  as  organic  beings. 

VoLVOX  Glohator   (INI.)  (xx.  32-47)    rent  difference  between  them  consistinor 


(p.  180  et  seq.). — So  called  from  the 
globidar  figm-e  of  the  aggregate  mass  or 
colony  constituted  by  the  individual 
mona'difonn  beings  or  gonidia.  When 
blue  or  red  coloming  matter  is  mixed 
with  the  water,  strong  currents  may  be 
observed  under  the  microscope  aroimd 
each  globe,  which,  when  in  motion, 
always  proceeds  with  the  same  part 
foremost,  xx.  32  represents  a  large 
globe  -^dth  eight  smaller  ones  (termed 
by  Ehrenberg,  sisters)  within  it.  xx.  34 
is  a  section  of  a  globe,  more  magnified. 
xx.  35  represents  three  gonidia  in  situ 
within  the  common  envelope.  In 
shallow  pools  of  clear  water,  in  spring 
and  siunmer.  The  largest  globes  mea- 
sure 1-30"  in  diameter ;  the  smallest 
free  swimming  ones  1-360"  to  1-240". 
Size  of  a  single  corpuscle  1-3500". 

Ehrenberg  notified  the  peculiar  occur- 
rence of  living  Rotatoria  within  the 
globes  of  the  Volvox  Glohator.  Mr.  John 
WiUiams  has  communicated  {T.  31.  S. 
1851,  iii.)  an  interesting  observation, 
confirming  Ehrenberg's  account. 

Within  the  cavity  of  a  large  specimen 
of  this  species,  evidencing  its  usual 
vitality,  and  the  ciliary  movements  on 
its  surface,  he  noticed  a  very  active 
Rotifer,  which  he  believes  to  have  been 
the  Kotommata  parasitica,  and  which 
was  subsequently  accompanied  by 
another  of  the  same  species,  t3ut  smaller. 
He  adds,  "  By  the  most  careful  examina- 
tion, no  opening  coidd  be  perceived  by 
which  they  coidd  have  been  introduced ; 
neither  did  there  appear  to  have  been 
any  viscera  by  which  their  motions 
might  be  impeded,  as  they  swam  about 
as  freely  as  fish  in  a  glass  globe,  to 
which,  indeed,  they  bore  no  faint  resem- 
blance." 

The  two  following  species,  named  V. 
aureus  and  V.  stellatus,  ai*e,  in  the  opinion 
of  Profs.  Busk,  Williamson,  and  Perty, 
merely  developmental  phases  of  V.  Glo- 
hator—  V.  stellatus  being  the  later  stage. 
"  V.  aureus''^  says  the  A\Titer  first  named 
(op.  cit.  p.  32),"  exhibits  precisely  the  same 
structure  as  V.  Glohator,  the  only  appa- 


in  the  deeper  green  colom'  of  the  internal 
globes.  These,  however,  soon  exhibit  a 
more  important  distinctive  character,  in 
the  formation  of  a  distinct  cell-weU  of 
considerable  thickness  aroimd  the  dark- 
green  globular  mass.  This  wall  becomes 
more  and  more  distinct ;  and  after  a  time 
the  contents  change  from  dark  green  into 
a  deep  orange-yellow,  and  simultaneously 
with  this  change  of  colour  the  waU  of  the 
globule  acquires  increased  thickness,  and 
appears  double. 

"  The  third  foi-m,  or  V.  stellatus,  differs 
in  no  respect  from  the  two  foimer,  except 
in  the  form  of  the  internal  globules, 
which  exhibit  a  stellate  aspect,  caused 
by  the  projection  on  their  surface  of 
numerous  conical  eminences  fonned  of 
the  hyaline  substance  of  the  outer  waU. 
The  deep  colour  of  the  contents  of  their 
embiyos,  and  their  change  uito  an  orange 
colour,  at  once  point  out  their  close 
analog}^  with  those  of  V.  aureus.  I  have 
no  doubt  of  their  being  mere  modifica- 
tions of  the  latter,  and  I  have  obsen-ed 
smooth  and  stellate  globules  in  the  in- 
terior of  one  and  the  same  parent  globe.'' 

Mr.  Carter,  however,  does  not  share 
this  opinion  with  reference  to  V.  stellatus, 
which  he  treats  {A.  N.  H.  1859,  iii.  p.  6) 
as  a  distinct  species. 

These  extracts  from  recent  and  well- 
known  authorities  are  further  valuable 
as  supplying  an  explanation  of  Laurent's 
statements  that  two  sorts  of  reproduc- 
tive bodies  appear  in  the  globes  of  Vol- 
vox. Little  weight  is  attached  to  this 
gentleman's  microscopical  researches, 
which  are  mostly  ideal. 

V.  aureus.  —  Green,  nearly  globular. 
The  small  secondary  globes  within  them 
are  of  a  golden  colom*,  and  smooth  sur- 
face. In  rain-water  standing  on  tmi. 
Diam.  of  globe  1-30". 

V.  stellatus. — Small,  subglobose,  some- 
times oblong,  or  of  an  augidar  form,  and 
gTeen  colour.  The  contained  globes 
within  them  are  of  a  green  colour,  and 
have  their  surfaces  tuberculated  or  stel- 
lated.    Diam.  of  globe  1-30". 

Carter,  who  accepts  this  species,  de- 


528 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOKIA. 


the  quaint  terms  "  daugliters "  and 
*' grand-daug'liters  "  for  the  "primary" 
and  '^  secondary  "  generations  or  gemm?e 
of  the  parent  globe  of  the  Volvox  : — 
''  Adult  form. — Globular,  slightly  ovoid, 
consisting  of  three  generations  or  families 
within  one  another ;  containing  generally 
eight  daughters,  in  each  of  which  there 
are  generally  eight  grand-daughters  in- 
cUstincUy  visible.  Daughters  confined  to 
the  posterior  three-fourths  of  the  sphe- 
roid, the  anterior  fom*th  being  empty. 
Progressing  with  the  empty  end  for- 
wards. Daughters  rotating  (this  marks 
the  adult  foi-m  here  also)  in  their  cap- 
sules respectively,  which  are  fixed  to  the 
internal  periphery  of  the  parent.  Grand- 
daughters small  and  indistinct,  motion- 
less, and  fixed  to  the  internal  periphery 
of  the  daughters  respectively.  Peripheral 
cells  conical  and  biciliated,  not  uniciliated 
as  figured  by  Ehrenberg.  59-1880"  long 
and  54-1880"  broad." 

In  his  subsequent  remarks,  he  makes 
it  the  specific  point  of  difierence  between 


the  primary  gemmse  of  this  V.  steUutus 
and  V.  Glohator,  that  those  of  the  former 
begin  to  undergo  duplicative  subdivision 
almost  immediately  after  they  appear,  or 
"  at  the  time  when  they  do  not  exceed 
three  times  the  diameter  of  the  peri- 
pheral cells,"  or  1-2700",  instead  of  "not 
passing  (as  in  V.  Glohator)  into  small 
cells  until  they  have  arrived  at  more 
than  the  1-300"  in  diameter."  He  also 
alludes  to  difierences  between  these  two 
species  in  the  form  of  the  spermatozoids 
and  the  mode  of  fecundation.  We  ven- 
ture to  remark  that  if  these  latter  par- 
ticidars  are  sufficient  to  indicate  specific 
differences,  it  is  not  so  with  the  size  of 
vegetable  cells  at  which  fission  may 
commence.  The  history  of  all  the  sim- 
plest cellular  organisms  we  know  of 
shows  that  the  period  of  cell-life,  and 
therefore  the  dimensions  of  the  cells  at 
which  it  occurs,  stands  in  no  constant 
relation  with  the  act  of  fission.  The 
size  of  a  cell  and  the  proclivity  to  fission 
depend  much  on  external  conditions 
affecting  its  vital  activity. 


The  following  genera  are  distinguished  by  Perty : — 

Genus  SYNAPHIA  (Perty), — Corpuscles  from  10  to  12,  aggregated  together 
within  a  spherical  gelatinous  envelope,  in  mutual  contact,  so  as  to  form  a 
compact  mass.  The  corpuscles,  each  furnished  with  a  single  filament,  arc 
not  spherical  but  angular  and  wedge-  or  pear-shaped,  with  the  wide  end 
turned  towards  the  pheriphery.  In  very  exceptional  specimens  the  gonidia 
are  somewhat  separated  from  each  other.  Length  of  filament  equal  to,  or 
1^  the  diameter  of  the  corpuscle,  and  very  fine.  The  relation  between 
Gonium  and  Pediastrum  has  been  noted  by  Cohn  and  other  observers ;  but- 
that  between  this  newly- constituted  genus  of  Perty  and  the  second-named 
group  is  much  more  striking,  whether  the  description  given  or  the  illustrative 
figures  be  considered;  indeed  the  impression  forces  itself  upon  us,  that 
Synaphia  is  simply  a  form  of  Pediastrum.  This  impression  is  moreover 
strengthened  by  the  fact  mentioned  by  Perty,  that  the  movement  of  the 
organism,  and  the  fine  filament,  disappear  as  the  organism  advances  in  age 
and  dimensions. 


Synaphia  Dujardinii  (Perty). — Cor- 
puscles clear  green  to  dark  or  blackish 
green,  measuring  within  the  enclosing 
envelope  1-1300"  to  1-360",  more  com- 
monly fi'om  1-720"  to  1-480".  Move- 
ments torpid  or  tolerably  quick,  around 
one  or  other  axis,  always  oscillating. 
The  filaments  are  only  visible  when  the 
spherical  colony  is  at  rest.  The  radi- 
ating grouping  of  the  individual  gonidia 
is  not  completely  sjTumetrical ;  some- 
times the  spherical  figure  is  exchanged 


for  an  ellipsoid.  The  gelatinous  envelope 
varies  in  breadth,  is  clear  and  trans- 
lucent, rarely  having  a  red  blush  under 
the  microscope,  and,  in  large  specimens, 
frequently  divided  by  fine  lines  into 
two  or  three  halos.  When  d}dng,  the 
several  corpuscles  detach  themselves,  and 
after  death  do  not  undergo  diflluence, 
but  turn  yellow  and  idtimately  dissolve 
away.  Frequently  a  green  granule  is 
visible  internally,  and  a  scarcely-dis- 
cernible red  point. 


Genus  HIRMIDIUM  (XIX.  15)  (Perty).— A  chain  of  from  4  to  8,  very 
small  rounded  corpuscles  of  a  pale  green  colour,  siuTounded  by  a  gelatinous 


0¥  THE  VIBRIONIA,  529 

envelope.  This  genus  appears  to  us  very  erroneously  referred  to  the  Volvoeina  ; 
but  the  figures  given  are  not  sufficient  to  determine  to  what  family  they  more 
rightly  belong. 

HiRMiDiuM  i7iane  (xix.  15). —  Cor-  'common  envelope  inconspicuous.  Length 
puscles  irregidarly  spherical,  almost  cup-  j  of  chain  1-360" ;  size  of  individual  cor- 
shaped,  and  probably  furnished  each  with  puscles  1-1900".  From  its  smallness,  this 
two  filaments.  Some  very  tine  molecules,  j  organism  is  difficult  of  observation,  and 


one  generally  of  a  hark  hue,  perceptible 
internally.  The  chain  advances  quickly 
by  revolving  on  its  long  axis ;  gelatinous ; 


requires  further  investigation.  Only  in 
small  numbers,  in  some  ponds  in  the 
canton  of  Bern. 


Wemeck  characterized  several  new  genera,  which  he  referred  to  the  Poly- 
gastrica  of  Ehi^enberg  {Monatsh.  der  BerJ.  Akad.  1841,  p.  377),  two  of  which 
are  to  be  inserted  in  this  family,  as  allies  of  Pandorina,  and  are  veiy  briefly 
characterized  under  the  names  of  Ccdia  and  Stephanoma : — 

CALIA. — Monads  imbedded  in  a  gelatinous  mass,  affixed  to  plants,  and 
not  swimming  freely  about.  Two  species  are  kno^vn  ;  the  characters  not  given. 
This  genus  is  very  probably  nothing  more  than  one  of  the  simple  Algae. 

STEPH AN OM A =P«ncZorma  with  a  single  zone  of  corpuscles,  which  divide 
like  the  cells  of  Gonium.  One  species  observed  exhibiting  a  circlet  of  sphe- 
rules united  to  form  a  wi'eath  or  zone.  This  genus  is  probably  the  same  as 
Stephanosphc^ra  (Cohn,  A.  N.  H.  1852,  p.  407). 

Genus  STEPHANOSPH^ERA  (Cohn)  (XIX.  38-58).— A  family  of  cells, 
rotating  and  moving  throughout  life ;  composed  of  eight  green  primordial 
ceUs,  each  bearing  tivo  active  cilia ;  arranged  at  equal  distances  in  a  circle, 
enclosed  in  a  common  hyaline  globose  vesicle,  or  common  envelope;  pro- 
pagated both  by  ynacrogonidia  (originating  from  eightfold  division  of  each  of 
the  green  cells),  which  bear  two  cilia,  and  are  congregated  into  eight  octonary 
families,  and  by  very  numerous  smaller  microgonidia  (produced  by  multifold 
division),  revolving  at  first  T\ithin  the  common  vesicle  by  the  action  of  four 
cilia,  and  then  escaping  singly. 


Stephanospioera  jyluvialis. — Green^ 
cells  globose,  elliptical,  or  fusiform,  often 
running  out  into  mucous  rays  at  both 
ends.  Diameter  of  the  cells  =  l-330th  to 
l-180th  of  a  line  (0-0065  to  0-012  umi.)  ; 
diameter  of  common  vesicle  =  l-80th  to 


l-40th  of  a  line  (0-028  to  0-055  mm.). 
Revives  after  desiccation.  Inhabits 
hollow  stones  filled  with  rain-water,  in 
company  with  Chlamydococciis  pluvialts : 
Salzburg,  Wemeck  ? ;  Zamora,  A.  von 
Frantzius  ]  Hirschberg,  Von  Flototv, 


Dr.  Strethill  Wright  has  met  with  Stephanosphcera  in  Scotland. 

FAMILY  v.— VIBRIONIA  (see  p.  184). 

(XVIII.  57-69.) 

According  to  Ehrenberg,  the  members  of  this  family  are  distinctly  or  ap- 
parently polygastric,  but  without  a  true  alimentary  canal;  have  neither 
appendages  nor  lorica,  and  are  incapable  of  changing  the  form  of  their  body. 
They  are  linked  together  in  thread-like  chains,  formed  by  their  imperfect 
transverse  self- division.  Information  respecting  the  Vibrionia  is  very  im- 
perfect ;  this  is  attributable  to  the  exceeding  minuteness  of  the  individual  ani- 
malcules which  compose  the  chains.  These  last  have  never  any  determinate 
length,  or  number  of  component  corpuscles,  and  they  are  sometimes  so  short 
as  to  be  made  up  of  not  more  than  two  or  three  individuals,  which  are  only 
distinguishable  from  Monas  Termo  and  M.  Crep>usciduin  by  their  union  in 
chains,  and  by  their  peculiar,  though  not  easily  characterized  movements. 
The  motion  of  the  chains  is  generally  of  a  writhing  character.     In  one  genus 

2  M 


530 


SYSTEMATIC  HISTORY  OF  THE  INFUSOfilA. 


(Bacterium),  a  single  vibratory  filament  is  present.  In  this  same  genus  the 
individuals  are  strung  more  tightly  together,  so  that  the  filiform  cluster,  not 
being  able  to  exert  the  writhing  movement  seen  in  the  true  Vibrionia,  moves 
rigidly  in  a  direct  course.  In  Sinrillimi  the  articulations  or  lines  of  imperfect 
fission  are  oblique ;  hence  increase  in  length  by  division  engenders  a  spiral 
chain. 

The  animals  of  this  family,  says  Dujardin,  "are  the  first  Infusoria  which 
present  themselves  in  all  infusions,  and  those  which  from  their  extreme  small- 
ness  and  the  imperfection  of  our  means  of  observation  must  be  considered  the 
most  simple ;  ....  and  it  is  only  their  more  or  less  active  movements  which 
lead  to  their  being  regarded  as  animals.  I  have  been  sometimes  induced  to 
believe  that  a  flagelliform  filament,  analogous  to  that  of  Monads,  or  rather  a 
spiral  undulating  one,  exists,  and  that  this  is  the  cause  of  the  peculiar  mode 
of  locomotion.  Is  the  Bacterium  tiiloculare,  described  by  Ehrenberg  as  having 
a  proboscis,  a  true  Yibrio  ? 

*'  All  that  can  be  with  certainty  predicted  respecting  their  organization  is 
that  they  are  contractile,  and  propagate  by  spontaneous  fission,  often  imperfect, 
and  hence  giving  rise  to  chains  of  greater  or  less  length." 

As  stated  in  our  general  history  of  the  family  (p.  184),  the  present  tendency 
among  natiu^alists  is  to  refer  Vibrionia  to  the  vegetable  kingdom.  Cohn 
assigns  them  a  place  in  the  family  Mycophycese  among  the  microscopic  aquatic 
Eungi.  Perty  retains  them  in  his  group  Phytozoida,  expressing  at  the  same 
time  his  conviction  that  they  are  of  a  vegetable  nature.  Indeed  the  only 
reasons  advanced  by  Ehrenberg  in  support  of  the  animality  of  Vibrionia  are, 
that  they  are  actively,  and,  to  his  apprehension,  voluntarily  moving  beings, 
and  multiply  by  self- division, — reasons  which,  in  the  present  state  of  know- 
ledge, must  be  held  worthless,  A  re- examination  of  aU  the  enumerated 
species,  as  Cohn  remarks,  is  imperatively  necessary  before  we  can  come  to 
any  safe  conclusions  relative  to  the  true  structure  and  affinities  of  the 
Vibrionia ;  and  this  same  able  observer  has  himself  set  the  example  by  con- 
ducting such  an  examination  of  one  species  as  to  clearly  indicate  its  physio- 
logical characters  and  its  relation  to  PalmeUa  and  Tetraspora  among  the 
Algae,  and  more  particularly  to  Sjjhcerotilus  among  Mycophyceaj. 

The  Vibrionia  are  developed  with  extreme  rapidity  in  aU  liquids  containing 
changed  or  decomposed  organic  substances,  in  animal  fluids — the  saKva,  serum, 
mine,  &c.  When  coloming  matter  has  been  mingled  with  the  water,  its 
imbibition  by  the  corpuscles  has  never  been  observed. 

This  family  is  distributed  by  Ehrenberg  as  follows : — 

Articulated       threads       (clusters)  f  Inflexible Bacterium. 

straight,  the  transverse  divisions  i 

being  rectangular   [  Flexible,  Hke  a  snake Vibrio. 

Articulated  threads  spirally  twisted  r^lexible   Spirochajta. 

(like  a  bell-spring  or  cork-screw),  /    .,,  r   j-    n     i 

%J:r''''    clivisions    bein^g  ^xtded^p^tiS^       '^^^^ 

^^l^^l^"    Unflexible.     '  ^ 


I  with    a    compressed  I    g  i^odiscus. 
l^  spiral  lorm    J      ^ 


On  this  subdivision  of  the  family  Vibrionia,  Cohn  (Entiu.  p.  117)  has  ex- 
pressed himself  very  strongly.  He  says,  ^'  An  inextricable  confusion  prevails 
when  specific  characteristics  are  attempted  :  we  have  the  observations,  good 
and  bad,  of  various  authors,  weak  and  strong  amplification  of  the  objects, 
young  and  old  conditions  commingled  without  any  critical  endeavour  to 
distinguish  between  them."  Eeehng  that  there  is  no  sufficient  basis  for  it, 
Cohn  does  not  attemjit  a  classification  of  the  Vibrionia.     The  Monas  Lineola 


OF  THE  VIBRIONIA.  531 

(E.)  or  Bacterium  Termo(D\\}.)w,,  according  to  his  Avell- conducted  investiga- 
tions, no  other  than  the  swarming  stage  of  a  microscopic  aquatic  fungus 
belonging  to  the  Mycophyceae,  of  which  he  makes  a  new  genus,  named 
Zoogloea :  again,  Sjnrochceta  jylicatilis  is,  in  his  opinion,  an  Alga  of  the  genus 
Sinrulma,  and  the  stiif  Vibrios  allies  at  least  of  the  Oscillaria)a,  of  the  genus 
Beggiatoa ;  the  shorter  Vibrios  and  Sjpirilla  likewise  resemble  Oscillarisea  and 
Spirulina. 

Should  Cohn's  opinions  be  confirmed,  the  Vibrionia,  as  a  distinct  family, 
would  be  well  nigh  broken  up.  In  fact,  his  views  are  generally  acceded  to ; 
for  Perty,  Bm^nett,  and  others  all  point  out  their  peculiar  affinities  with  the 
Oscillariae,  and  discover  similar  forms  among  the  transitional  phases  of  various 
Algae,  and,  indeed,  among  the  antheridial  spores  of  higher  plants.  The 
value  of  Spirodiscus  as  a  genus  is  little  insisted  upon  by  Ehrenberg,  who 
instituted  it ;  and  in  all  probability  it  should  be  set  aside,  and  Spirochceta  also 
be  sacrificed  with  it.  The  only  species  of  Spirodiscus  named,  Perty  surmises, 
might  have  been  nothing  more  than  the  spore  of  a  fungus.  Dr.  Burnett  has 
expressed  himself  as  follows  to  the  same  effect ;  for  he  observes,  "  When  we 
come  to  organisms  as  minute  as  these,  the  distinguishing  characteristics  of 
genera  and  species  become  too  obscure  and  equivocal  to  have  much  value  ;  and 
the  best  microscopists  have  arrived  at  the  conclusion  that  such  distinctions 
are  too  refined  and  will  not  bear  the  test  of  exi^erience. 

"  The  genus  Vibrio — the  simplest — I  regard  as  the  first  appearance  of  the 
young  Alga,  existing  then  as  the  smallest  cells,  arranged  in  linear  series. 
The  genera  SpiriUum  and  Bacterium,  composed  of  larger  forms,  and  of  a  finer 
and  more  solid  structure,  represent  the  more  advanced  forms ;  and  as  all  Algoe, 
as  they  advance  in  size,  tend  to  consolidate  into  mycodcrmous  forms,  losing 
much  of  their  primitive  cell-structure,  so  these  two  genera  appear  to  have  lost 
their  old  beaded  type.  As  for  the  two  remaining  genera,  Spirochwta  and 
Spirodiscus,  but  little  is  positively  known.  They  scarcely  appear  to  belong 
to  the  other  forms  of  this  family ;  and  as  Ehrenberg  himself  has  expressed  a 
doubt  upon  the  subject,  one  may  as  well  omit  a  fiu-ther  notice.  Therefore, 
in  a  stmctural  point  of  view,  the  species  of  this  family  seem  to  be  only  Algoe 
at  different  stages  of  growth." 

Dujardin  instituted  only  three  genera  of  Vibrionia,  viz. :  1.  Bacterium — 
straight,  slightly  flexible  threads,  more  or  less  distinctly  jointed,  and  slow  in 
their  movements  ;  2.  Vibrio — either  straight  or  flexuose,  with  a  more  or  less 
\'ivacious  writhing  movement ;  3.  Sp)irillu7n — having  the  form  of  a  corkscrew, 
revolving  on  their  long  axis,  oftentimes  with  great  rapidity,  but  never  straight. 
Perty  has  made  a  more  ambitious  attempt  to  classify  these  minute  organisms ; 
of  its  utility,  however,  little  can  be  said,  for  oiu'  acquaintance  with  them  is  too 
imperfect  to  establish  satisfactorily  any  .distribution  of  them.  To  resume: 
Perty  makes  a  section  of  his  heterogeneous  group  Phytozoida,  which  he  calls 
Lampozoidia,  represented  by  the  one  family  "  Vibrionida."  The  *^  Lampo- 
zoidia  "  are  defined  as  "  colourless,  or  rarely  blue,  yellow,  or  red,  never  green, 
organisms,  without  special  organs,  and  with  scarcely  a  trace  of  differentiation 
of  substance.  Their  motions,  though  seemingly  voluntary,  are  in  fact  only 
automatic.  They  multiply  by  transverse  fission,  and  in  so  doing  produce  chains 
and  fibres."  Of  the  family  Vibrionida,  two  varieties  are  distinguishable : — 
A.  Spirillina,  in  which  the  chain  or  fibre  is  spii^ally  coiled ;  B.  Bacterina,  in 
which  it  is  contorted  or  straight.  Spirillina  contains  two  genera,  Spirochceta 
and  Spirillum ;  whilst  Bacterina  is  made  up  of  four,  viz.  Vibrio,  Bacterium, 
Metallacter,  and  Sporonema.  The  new  genera  named  will  follow  after  our 
account  of  those  recognized  by  Ehrenberg,  and  the  notes  on  the  others  in 
their  proper  places. 

2m2 


532 


SYSTEMATIC  HISTOKY  OF  THE  TNFrSOETA. 


Genus  BACTERIUM. — Yibrionia  distinguished  by  the  corpuscles  being 
connected  together  in  a  thread-like  more  or  less  rigid  or  inflexible  chain,  and 
by  multiplying  by  transverse  self-division  at  right  angles  to  the  chain. 

The  three  species  kno^Ti  are  colourless,  and  extremely  minute.  Ehi^enberg 
remarks  "  that  only  one  of  the  species  has  been  satisfactorily  determined, 
and  that  their  organic  relations  are  altogether  so  obscure,  that  our  judgment 
respecting  them  must  unavoidably  be  left  in  a  fluctuating  state."  In  B, 
trUoculare  a  vibratorj"  proboscis,  a  granular  mass  within  the  body  of  the  crea- 
ture, and  spontaneous  division  are  discoverable.  All  the  species  enjoy  an 
active  power  of  locomotion.  Perty  says  that  he  is  unacquainted  with  the 
species  of  Bacterium  enumerated  by  Ehi'cnberg. 

A  magnifying  power  below  500  diameters  will  not  exhibit  the  divisions 
or  transverse  lines  between  the  individuals  or  links  of  the  wand  or  chain. 
Bacterium  occui^s  around  decomposed  vegetable  matter,  on  the  surface  of  water 
containing  Chara,  &c. 


Bacterium  triloculare.  —  Chain  in 
the  form  of  short  cylinders  of  fi'om  two 
to  five  oval  corpuscles,  and  generally 
about  three  times  as  long  as  their  dia- 
meter;  transverse  junction-lines  distinct. 
Ehrenberg  has  observed  not  more  than 
five  links  together,  nor  less  than  two. 
<'By  throwing,"  he  adds,  "  a  little  colom-- 
ing*  matter  into  the  water,  an  evident 
vibration  may  be  perceived  near  the  an- 
terior portion  of  the  corpuscle  or  of  the 
chain  ;  and  upon  a  veiy  close  inspection 
a  simple  fihform,  though  short,  proboscis 
mav  be  seen,  which,  in  the  larger  speci 


mens,  is  one-third  the  length  of  the  body, 
and  in  the  smaller,  one-half."  The  motion 
of  this  creature  is  tremulous,  or  slowly 
revolving  upon  its  longitudinal  axis. 
In  the  water  of  bogs.  Length  of  chain 
1-4800"   to    1-2304";    single    coi-puscle 

Genus  VIBRIO. — Characterized  by  the  corpuscles  being  connected  together, 
through  incomplete  self-division,  in  filiform  flexible  chains  resembling  in 
miniatui-e  the  figm^e  and  movements  of  a  snake.  Junction-lines  at  right 
angles  to  chain. 


1-11520"  (xviu.  57).  Group  57  repre- 
sents several  of  them ;  t^'o  towards  the 
right  are  magnified  1000,  the  others  290 
diameters. 

B.  Enchelys.  —  Chain  composed  of 
somewhat  indistinct,  colomless,  oval 
coi-puscles  united  in  smaller  cylinders 
than  the  preceding ;  ti'ansverse  lines 
faintlv  marked.  In  river  water.  Length 
of  chain  1-2880". 

B.  Pimctum. — Chain  cylindrical,  com- 
posed of  indistinct,  colourless,  globose 
coi*puscles  ;  much  smaller  than  the  pre- 
ceding species  ;  transverse  lines  faintly 
marked.  In  water  wherein  bread  has 
been  steeped.    Length  of  chain  1-4032". 

B.  Catenula  (D.). — Filifomi,  cylindri- 
cal. Length  of  individuals  1-8600"  to 
1-6500" ;  3,  4,  or  5  are  united  together, 
formino-  a  chain  1-1300"  in  lenoth. 


Vibrio  Lineola  (Bacterium  Termo, 
Dnj.)  (xvin.  69). — Forms  a  minute 
cvlindrical  and  slightly  flexible  wand, 
rounded  at  both  ends;  separate  cor- 
puscles somewhat  indistinct,  of  nearly 
globular  form,  and  colourless.    Common 


greeable  odorn*.  Length  of  wand  1-3600". 
V.  suhtilis. — Wand  slender  and  elon- 
gated ;  colourless :  articulations  distinct ; 
motion  slightly  vibrating,  vrithout  vary- 
ing the  direct  position  of  the  articula- 
tions. Lenoth  1-450";  thiclmess  1-24000". 


in  veo-etable  infusions,  especially  around    Perty  says  this  species  is  only  a  variety 
the  stalks  of  floAvers  in  glasses,  and  in  ;  of  _F.  (3ietnllacfer)  Bacillus. 
foul    ponds.      Length    of  wand,    from 


1-3600"  to  1-200".  Thickness  1-3600". 
Both  Cohn  and  Perty  join  in  the  use  of 
Dujardin's  name  for  this  species,  and  in 
representing  Ehrenberg  as  in  error  in 
identifsing  and  fixing  its  characters  (see 
genus  Zooglcea). 

V.  tretnulans.— Wand  short;  stouter, 
yet  more  flexible,  than  the  preceding; 
articulations  of  an  oblong  form,  not 
distinct.       In    water   emitting    a    disa- 


V.  Bugula  {Vibrio  Rugula,  M.)  (x^^II. 
64). — Wand  elongated  ;'  stouter  than  the 
precedmg;  articulations  distinct;  and 
colourless  ;  motion  brisk  and  serpentine ; 
common  in  infusions  and  foul  water. 
Length  1-580"  ;  thickness  1-12000". 

Y.prolifer, — Wand  short,  stout,  and 
colourless';  articulations  distinct.  Mo- 
tion slow  and  tortuous.  In  infusions 
where  mildew  is  present.     1-1100". 

V.  Bacillus  (M.)  =  3Ietallaeter  Bacillus 


OF  THE  VIBEIONIA. 


533 


(Perty). — Wand  stout,  elongated,  and 
transparent ;  articulations  distinct,  or  be- 
come so  when  dried ;  motion  sei-pentine ; 
form  straight  when  quiescent  (xviii.  62). 
In  vegetable  infusions  and  fetid  water. 
Length  1-200";  thickness  1-17200". 

\.  sijnxanthus. — Wands  (bacilli)  very 
fine  and  short,  rather  fiexuose,  rarely,  of 
more  than  five  segments  (individuals), 


yellow  and  minute.  Corpuscles  1-70000" 
to  1-52000".  In  decomposing  cow's- 
milk,  in  which  it  produces  a  yellow  tint. 
V.  syncyanus. — Wands  very  slender 
and  short,  somewhat  flexuose,  of  seldom 
more  than  five  segments,  verv  small,  and 
of  a  blue  colour.  1-78000"  to  1-52000". 
Also  found  in  cow's-milk,  in  which  it 
produces  a  decided  blue  shade. 


The  foLlowiiig  species  are  from  Dujardin's  work 


V.  seiycns  (M.). — Body  ver\^  long,  fili- 
form, undulating,  generally  pm-suing  a 
rectilinear  course,  with  from  ten  to 
fifteen  bends  in  its  length.     1-1050". 

V.  amhiyuus. — Under  this  name,  Du- 
jardin  describes  a  Vibrio  with  stift'  fili- 
form joints  like  those  of  V.  Bacillus,  but 
much  larger  (xviii,  60).     Four  or  five,  1 
or  even  more,  were  articulated  together;  1 
owing  to  the  large  dimensions,  each  joint  i 
could  be  seen  composed  of  a  resistant  I 


tube,  in  which  a  glutinous  substance  was 
more  or  less  closely  packed.  Moreover, 
a  bifurcation  at  the  extremity  of  a  joint 
was  sometimes  seen  to  occur,  giving  rise 
to  two  rows  of  branching  chains,  of  more 
or  less  length. 

Such  observations  tend  to  render  the 
animality  doubtful,  not  only  of  this 
Vibrio,  but  also  of  the  similar  but  smaller 
V.  Bacillm. 


Genus  SPIROCHtETA. — Chains  spiral,  filiform  and  flexible,  lengthening 
by  the  imperfect  or  incomplete  mode  of  self- division.  The  details  of  orga- 
nization are  at  present  unknown.  Dujardin  does  not  admit  this  as  a  genus 
distinguishable  from  SinriUum ;  and  Cohn  is  unable  to  discover  any  suf- 
ficiently distinctive  characters  between  this  and  the  acknowledged  vegetable 
genus  Spindina.  Spirochceta  moves  with  an  immense  activity,  surpassing 
what  is  observed  in  the  recognized  species  of  Spirulina  ;  but  this  difference 
is  not  suflicient  to  separate  the  two  genericaUy.  Spirulina  plicatdis  is  figured 
(XVIII.  67,  68).  Cohn  moreover  inclines  to  the  opinion  that  Spirulina, 
Spirochceta,  and  Sj)irillum  are  members  of  one  common  group  of  organisms  of 
a  vegetable  nature.  The  distinctive  feature  between  Spirillum  andSpfirulina 
is  the  smaU  number  of  corpuscles  found  united  in  the  chains  of  the  former 
compared  with  the  latter. 

SpiEOCH^TA/>//cff^«//"s  (Vibrio  serpens, 
M.)  (x^^II.  63). — Coi"puscles  very  deli- 
cate, nearly  globidar,  connected  together 
in  a  long,  filiform,  spiral  chain,  ha\nng 


numerous  and  closely -arranged  coils; 
colourless.  At  Tilbury  Fort.  Length 
of  chain  1-170"  to  1-440" ;  thickness 
1-12000." 


Genus  SPIRILLUM. — Developes  in  the  form  of  tortuous  chains,  or  of 
inflexible  and  cylindrical  spirals.  The  incomplete  self-di\T.sion,  which  is 
obHque  in  direction,  produces  the  characteristic  coiKng  of  the  chain.  Motion 
brisk  and  energetic. 


Spirillum  tenue. — Spiral  of  three  or 
foiu"  coils,  constituted  of  very  slender, 
slio;htly  bent  colom-less  fibres ;  articu- 
lations distinct.  In  vegetable  infusions. 
Length  about  1-900";  thickness  1-1200". 

S.  Undula  (  Vibrio  JJndula,  M.)  (xviii. 
59-61). — Spiral  of  one  turn  and  a-half ; 
corpuscles  short,  stout,  and  much  bent ; 
articulations  distinct ;  colourless  ;  when 
dry,  the  articulations  are  more  distinct. 
In  stagnant  water  having  a  mildew 
scent.  Length  about  1-1500"  ;  thickness 


1-20000".  This  species,  Perty  remarks, 
frequently  grows  so  as  to  form  clusters 
or  masses  which  are  motionless,  and, 
like  all  the  rest  of  the  Vibrionia,  never 
produces  true  vegetable  fibres. 

S.  volutans  (  Vibrio  S^nr ilium,  M.), — Of 
three,  four,  or  more  coils  ;  fibres  very 
tortuous,  long-,  and  stout;  articulations 
distinct ;  colourless.  In  vegetable  infu- 
sions. Length  of  spiral  1-2200"  to 
1-500"  ;  thickness  1-14400". 


534 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Perty  adds  the  following  species  : — 

S.  rufum. — Has  the  figm'e  and  size  of 
S.  Undiila,  but  is  of  a  red  coloiu'.  No 
articulation  discoverable.  In  pond-water 
about  Bern,  which  had  been  kept 
S3veral  weeks.  The  claim  of  this  to  be 
considered  a  distinct  species  is  highly 
doubtful ;  for  its  only  assumed  charac- 
teristic, viz.  its  red  colour,  is  of  no 
weight,  being  in  the  Phytozoa  generally 
a  variable  condition,  due  to  chemico- 
vital  changes  in  the  organisms,  and 
ephemeral  in  duration. 

S.  (?)  Bnjozoon  (Unger)  (x\^i.  520- 
531). — Coils   consist  of  a  thick  body, 


with  a  delicate,  wavj^,  hair-like  proboscis. 
These  creatures,  found  in  the  reproduc- 
tive organs  of  plants,  were  called  by  their 
discoverer.  Dr.  Unger  of  Gratz,  spermatic 
animalcules,  and  are  described  in  detail 
in  the  Regenshiirger  Botan.  Flora,  1834 ; 
and  also  in  the  18th  vol.  of  the  Nova 
Acta  Nat.  Cur.,  Bonn,  1838.  A  con- 
densed view  of  this  subject  is  given  by 
Dr.  Meyen  in  the  Jahreshericht  for  1838, 
from  which  the  appended  translation  is 
made.  The  accompanjdng  illustrations 
(xvu.  520-531)  were  kindly  supplied  by 
Dr.  Unger  for  this  work. 


"  The  spermatic  animalcules  in  Sphagnum  consist,  according  to  the  earlier 
observations  of  Unger,  of  a  thick  body,  and  a  thin  filiform  tail ;  when  in  motion, 
this  tail  being  anterior,  he  considers  it  analogous  to  the  proboscis  (filament) 
of  many  of  the  Infusoria.  No  true  active  motion  of  the  body  itself  has  been 
observed  by  Unger ;  but  he  distinguishes  between  the  mere  locomotive  and  the 
rotaiy  movements  of  the  whole  animalcule.  The  simplest  motion  takes  place 
in  a  spiral  dii-ection ;  and  if  the  proboscis  is  contracted,  the  movement  is 
simply  rotary.  Diuing  the  locomotion  of  the  creature,  which  proceeds  in  a 
sj)ii'al  maimer,  Unger  saw  from  one  to  three  revolutions  of  the  body  in  a  second ; 
and  diuing  rotation  he  noticed  the  point  of  the  proboscis  to  be  in  a  continual 
state  of  tremor.  Unger  endeavom-ed  to  show  that  the  spermatic  animalcules 
of  the  mosses  are  analogous  to  the  spermatic  animalcules  of  animal  organisms, 
although  we  find  certain  features  in  the  former  not  seen  in  the  latter,  and 
which  may  somewhat  embarrass  their  classification,  the  chief  of  which  are 
the  steadiness  of  the  spiral  dii-ection  of  the  proboscis,  and  their  manner  of 
movement.  Lately,  Unger  has  foimd  spermatic  corpuscles  in  the  antheridia 
of  PolytricJium  juniperinum,  P.  commune,  P.  urnigerum,  and  P.  al])estre,  as 
weU  as  in  Fimarla  liygrometrka,  Bryum  cuspidatum,  B.  punctatum,  &c.  In 
Polytrichiim  commune,  the  corpuscles  are  found  in  very  small  hexahedi*al 
cells  with  roimded  comers.  Generally,  whilst  in  the  cells  they  are  motion- 
less ;  in  some,  however,  a  tremulous  motion  of  the  thin  proboscis  was  seen, 
and  in  others,  again,  a  rotatory  motion,  interrupted  at  intervals.  The  dia- 
meter of  the  delicate  proboscis  is  0-004  of  an  inch.  In  a  few  corpuscles, 
isolated  from  their  cells,  a  trembling  oscillating  motion  of  the  proboscis  was 
perceptible." 

To  these  particulars  may  be  added  a  remark  of  Dr.  Unger,  quoted  in  the 
Ann.  des  Sciences  Nat.,  which  led  to  the  introduction  of  the  subject  in  this 
work. 

"  The  doubts,"  Unger  says,  "  which  remain  concerning  some  of  the  organs 
of  the  animalcules  of  mosses,  further  increase  the  uncertainty  as  to  their 
situation  in  the  scale  of  beings.  From  aU  cii'cumstances,  I  am  incHned  to 
place  them  in  the  genus  S2nriUum  of  Ehrenberg,  and  to  describe  them  under 
the  name  of  S2)iriUum  Brgozoon.^' 

Mr.  Yaiiey,  in  his  article  on  Char  a,  in  the  50th  vol.  of  Trans.  Soc.  Arts,  has 
the  following  observations  on  the  same  structures  : — 

''  From  these  cells  "  [in  the  globule  of  the  axil  of  the  Chara~\  "  grow  out 
numerous  clusters  of  long  vessels,  possessing  the  most  extraordinary  features 
yet  observed.  \\Tien  these  are  first  protruded  from  the  globule,  if  not  quite 
mature  enough,  their  appearance  is  like  dense  or  strongly -marked  ringed 


OF  THE  VIUEIONIA.  535 

vessels,  the  divisions  of  which,  or  their  contents,  soon  begin  to  appear  irre- 
gular ....  After  a  while,  these  cmis  witliin  the  divisions  become  agitated : 
some  shake  or  vibrate ;  others  revolve  in  their  confined  i)laces ;  and  many 
come  out,  thus  sho"sving  that  they  are  spirals  of  two  or  three  cmis ;  these, 
with  an  agitated  motion,  s^vim  about ....  Now  the  field  of  view  appears  filled 
with  life  :  great  numbers  of  these  spirals  are  seen  agitated  and  moving  in  all 
dii'ections ;  they  all  have  a  directile  force,  one  end  going  foremost,  and  never 
the  other ;  many  stray  a  great  way  out  of  the  field :  these,  by  getting  clear 
of  each  other,  are  the  best  to  observe ;  they  do  not  quite  keep  theii'  form  as 
a  stifi"  sjDii'al,  but  their  foremost  end  seems  to  lash  about,  and  to  many  are 
seen  attached  almost  invisible  but  very  long  fibres.  These  fibres  were  in 
quick  undulations,  which  ran  in  waves  from  the  spiral  to  their  farthest  end. 
It  appears  that  these  fibres  cause  many  of  the  spirals  to  entangle  together, 
and  thus  bring  them  sooner  to  a  state  of  rest ;  therefore  the  separate  ones 
were  best  to  obser^'e." 

Among  the  more  recent  observations  on  these  motile  fibres  (from  the  anthers 
of  Chara  vulgaris  and  Ch.  liispidci),  are  those  of  M.  Thuretin  the  Annales  des 
Sciences  Naturelles,  a  translation  of  which  will  be  foimd  in  the  Annals  of 
Natural  History,  vol.  vii.,  from  which  we  extract  the  following  paragraphs : — 
"  The  portion  of  their  body  most  apparent  appeared  like  a  spirally-rolled 
thread,  of  three  to  five  curves.  They  were  shghtly  tinged  with  green,  similar 
to  the  nuclei ;  and,  like  them,  tiu-ned  brown  with  iodine,  their  two  extremities 
becoming  more  or  less  coloured  (according  to  the  quantity  of  iodine  employed) 
than  the  rest  of  the  body,  thus  indicating  a  difi'erence  of  natui^e  in  these  portions. 
At  a  Httle  distance  behind  one  extremity  proceed  two  bristles,  or  tentacula, 
of  excessive  tenuity,  which  the  animalcule  incessantly  agitates  wdth  great 
rapidity.  These  are  probably  organs  of  locomotion,  similar  to  the  filiform 
prolongation  found  in  the  Infusoria  without  cilia.  Indeed,  the  part  thus 
furnished  with  tentacula  moves  foremost,  di^awing  after  it  the  rest  of  the 
body,  which  turns  about  in  the  water,  but  always  preserves  its  corkscrew 
form.  The  incessant  agitation  of  these  tentacula,  and  theii'  extreme  tenuity, 
rendered  it  impossible  to  observe  them  in  the  living  animal ;  recourse  was 
therefore  had  to  the  evaporation  of  the  water,  or  to  the  application  of  a  sHght 
tincture  of  iodine,  when  the  animalcules  ceased  their  motions,  became  con- 
tracted, and  theii-  spii-al  unrolled,  when  the  tentacula  were  rendered  very 
distinct,  from  their  brown  colour.  These  tentacula  were  frequently  observed 
to  be  soldered  together  from  one-half  to  one-third  of  their  length  upwards ; 
but  others  were  also  noticed  to  be  entirely  separated  do-\vn  to  their  bases.  A 
sweUing  similar  to  that  in  the  flexui'e  of  the  body  was  perceived  in  their 
curves. 

"Ammonia  arrested  their  motions,  and  contracted  the  body  gradually  into 
a  small  oval  mass,  but  did  not  produce  the  phenomenon  of  decomposition  by 
solution  (diffluence),  so  remarkable  in  the  Infusoria.  A  very  weak  solution 
of  hydrochloric  acid  in  water  violently  contracted  them  into  a  shapeless  mass." 
In  Plate  XYII.,  figs.  520-522  represent  the  speiTQatozoa  found  in  Foly- 
frichum  commune,  the  first  figiu'e  exhibiting  them  enclosed  in  the  cellules,  and 
the  others,  swimming  freely.  Figures  522-524  are  taken  from  Marchantia 
poJijmo)2^Jia.  Figure  525  is  from  Sjjliagnum  capilli folium.  All  the  above 
are  magnified  1000  diameters.  Figures  b2Q-b2S  are  from  the  Chara  vulgaris, 
and  figiuTS  529-531  ivom.  Jungermannia  innguis,  as  figiu'ed  in  Meyen's  work 
{Neues  System  der  Pflanzen). 

On  this  subject  of  vegetable  spermatozoa,  Schleiden,  in  his  recent  work  on 
the  "Principles  of  Botany,"  remarks — "The  doctrine  of  vegetable  speimatozoa 
is  now,  I  hope,  gradually  dying  away.    The  gramdes  (generally  starch),  taken 


536  SYSTEMATIC  niSTORY  OF  THE  INFUSOEIA. 

from  spermatozoa,  have  indeed  lost  their  life  in  Fritzsche's  tinctiu'e  of  iodine, 
since  their  evidently  purely  physical  molecular  movement  remained  un- 
destroyed. 

''....  Fritzsche  has  completely  settled  the  matter ;  and  every  unprejudiced 
observer  may  convince  himself  with  ease  of  the  completely  untenable  natui'e 
of  the  wonders  formerly  spun  out,  especially  by  Meyen.  The  confirmatory 
observations  of  Nageli  on  this  point  are  also  of  great  value." 

Again,  he  says — ''  As  to  the  mechanism  of  the  motion,  we  know  just  as  little 
as  we  do  of  that  of  the  moving  cilia  ;  of  the  cause  of  motion,  of  the  motive 
power,  just  as  much  as  of  that  of  the  contraction  of  the  primitive  muscular 
fibre,  of  the  motion  of  animal  spermatic  filaments,  and  of  the  vibratile  ciUa 
on  animal  and  vegetable  cells ;  that  is  to  say,  absolutely  nothing." 

Fui'ther,  in  reference  to  the  motion  of  the  so-called  spermatozoa,  Schleiden 
observes — ^'  There  can  be  no  question  as  to  its  not  being  a  vital  phenomenon, 
because  the  motions  continue  even  in  the  alcoholic  tincture  of  iodine  (an 
absolute  poison  for  all  vegetable  and  animal  life),  of  which  one  may  readily 
convince  himself,  and  which  Fritzsche  has,  with  his  well-known  accuracy, 
shown  to  be  the  case  in  a  great  number  of  plants."  (Dr.  Lankester's  trans- 
lation, pp.  99  and  359.)  This  assertion  of  Schleiden,  that  tincture  of  iodine 
is  an  absolute  poison  to  all  animal  and  vegetable  life,  must  be  received  with 
reserve,  since  animalcular  life  has  been  known  to  exist  in  agents,  such  as 
strong  acids  and  mineral  poisons,  which,  a  priori,  would  appear  quite  as 
inimical  to  it  as  tincture  of  iodine ;  and  even  minute  animals — the  Acari,  of 
far  higher  organization  than  the  Polygastrica,  have  been  stated  to  presei-ve 
life  in  strong  acetic  acid. 

Before  dismissing  this  subject,  it  may  be  useful  to  append  some  observa- 
tions made  by  Wagner  and  Leuckart,  in  their  elaborate  and  original  article 
before-quoted. 

Having  stated  that,  up  to  the  most  recent  period,  the  so-named  spermatozoa 
of  animals  have  been  considered  independent  animal  organisms,  or  parasitical 
animals,  and  classed  among  the  Infusoria,  the  authors  proceed  to  say  that 
such  assumption  is  perfectly  irreconcileable  with  our  present  knowledge  of 
these  bodies,  derived  principally  from  the  discoveries  of  R.  Wagner,  Von 
Siebold,  and  Kolliker : — "  With  our  existing  means  of  scientific  diagnosis  it 
can  be  proved  that  the  formations  in  question  are  mere  elementary  consti- 
tuents of  the  animal  organization,  like  the  ova — constituents  equally  as  neces- 
sary for  the  spermatic  fiuid  as  the  blood-globules  are  for  the  blood.  The  re- 
markable phenomena  of  the  life  of  spermatozoa  are  quite  analogous  to  those 
phenomena  of  motion  observable  not  only  in  animal  formations,  but  also  in 
vegetable  structures — as,  for  instance,  in  the  spores  of  Algae  and  of  the  lower 
species  of  Fungi,  and  in  the  so -termed  Vihriones  which  grow  out  into  the  fibres 
of  the  Conferva  called  Hygrocrocis.  Moreover,  an  unprejudiced  observation  \d\\ 
prove  that  the  spermatozoa  are  eveiywhere  void  of  a  special  organization,  and 
consist  of  an  uniform  homogeneous  substance,  which  exhibits,  when  examined 
by  the  microscope,  a  yellow  amber-like  ghtter.  The  opinion  of  an  internal 
organization  of  the  developed  animal  elements  was  not  a  little  supported  by 
the  various  remarkable  phenomena  of  motion  which  were  frequently  perceived 
in  them.  In  former  times,  when  people  had  no  idea  of  the  existence  and 
extent  of  the  so-called  automatic  phenomena  of  motions  which  take  place 
without  the  intervention  or  influence  of  the  nervous  system — when  nothing 
was  known  of  the  motion  very  similar  to  a  voluntary  one  which  exists  even 
in  plants — this  movement  was  certainly  calculated  to  place  the  independent 
animal  nature  of  the  spermatozoa  beyond  a  doubt.  But  it  is  different  now. 
We  know  that  motion  is  not  an  exclusive  atti'ibute  of  animals,  and  that  an 


OY  THE  VIBRIONIA. 


537 


inference  respecting  the  animal  nature  of  the  formations  in  question,  however 
similar  the  motion  observed  in  them  may  be  to  that  of  animal  organizations, 
is  a  veiy  unsafe  and  venturesome  one. 

"  We  know  that  certain  elementary  constituents,  animal  as  well  as  vegeta- 
ble, possess  a  power  of  movement,  and  that  they  retain  it  for  some  time  after 
having  been  separated  from  the  organisms  to  which  they  belonged.  We  only 
need  here  remind  our  readers  of  the  so-called  ciliated  epithelium,  the  several 
cells  of  which  swdm  about  in  the  fluid  surrounding  them,  and  have  not  un- 
frequcntly,  and  that  even  quite  recently,  been  considered  independent  animals ; 
or,  again,  of  the  spores  of  the  Algae,  which  actively  move  by  the  aid  of  a  ciHated 
investment,  or  of  a  single  or  manifold  long  whip-like  fibre,  until  they  eventually 
become  fixed  and  develope  themselves  into  a  new  plant.  Such  spores  as  these 
may  be  fomid  described  and  illustrated  in  the  well-known  magnificent  work 
of  Ehrenberg,  classified  as  Infusoria,  under  the  groups  of  Monadina,  Yolvo- 
cina,  &c. 

"  Under  such  circumstances  we  may  consider  ourselves  perfectly  justified 
in  declaring  every  attempt  to  prove  the  parasitic  natiu-e  of  the  spermatozoa 
by  the  characteristic  of  their  peculiar  motion,  as  futile  and  inadmissible." 

Genus  SPIRODISCUS  (XVIII.  63).— Self-division  imperfect  and  obHque, 
producing  elongated  chains,  or  inflexible  spirals,  of  a  disc-like  figure.  Its 
organization  is  so  little  known  that  Ehrenberg  considers  the  genus  as  by  no 
means  satisfactorily  determined ;  indeed  there  is  little  doubt  that  it  is  not  a 
member  of  the  Vibrionia. 


Spieodiscus  fulvus.  —  A  lenticular 
spiral,  of  a  yellowish  brown  colour. 
Articulation  indistinct,     xviii.  63  repre- 


sents three  spirals,  magnified  200  dia- 
meters. Amongst  Confervse.  Breadth 
of  spiral  1-1200". 


Genus  ZOOGLGEA  (Cohn). — Cells  (corpuscles)  very  minute,  bacilliform, 
hj'ahne,  aggregated  together  in  a  hyaline  muco-gelatinous,  globose  grape- 
like, and  subsequently  membranaceous  mass,  from  which  they  may  detach 
themselves,  and  swim  away  with  a  vacillating  movement. 


ZooGLCEA  Termo.  —  Free,  moveable 
cells,  straight,  from  1-2000'"  to  1-700'". 
It  is  equivalent  to  Palmella  infusmium 
(E.),3Iicmloa  teres  (vonFlotow),  to  some 


described  fonns  of  Cri/ptococeus,  and  to 
Bacterium  Termo  (i3uj.),  the  Vibrio 
Lineola  (E.)  (x^^ii.  69).  (See  Part  I. 
p.  187  et  seq.) 


Genus  METALLACTEE.  (Perty). — Bacterium-Y^kQ  corpuscles,  growing  by 
repeated  imperfect  division  into  stiff  or  shghtly  flexible  fibres  (chains),  which, 
under  certain  determinate  conditions,  eventually  lose  theii^  power  of  movement 
and  grow  into  Hygrocivcis-like,  tangled,  fibrous  masses,  colourless  or  of  a 
grejdsh  hue. 

Metallacteb  Bacillus  =  Vibrio  Ba- 
cillm.  —  Articulation  unobservable,  or 
seen  with  much  difficultv.      Vibrio  sub- 


tilis  (E.)  and  Bacterium  Catenula  (Duj.) 


are,  in  Perty 's  judgment,  nothing  more 
than  delicate  and  transparent  varieties 
of  this  same  organism.  In  Switzerland, 
in  foul  pond-water,  at  aU  seasons. 


Genus  SPORONEMA  (Perty)  (XVIII.  65).— Very  minute,  cyHndrical, 

unarticulated,  hoUow  fibres,  closed  at  one  end  (rarely  at  both),  frequently 
enclosing  two  eUiptical  corpuscles  (probably  spores). 

Spohokema  gracile  (x^^ii.  65).  —  |  Movements  tolerably  quick,  either  end 
Fibres  from  1-700"'  to  1-80'"  long,  and  ,  foi-ward.  Specimens  occur  where  the 
1-1000'",  and  under,  broad,  of  extremely  i  spores  distend  the  fibre;  others  contain 
pale-greenish  tint.  Often  occurs  with  !  none.  In  the  sediment  of  pond- water 
Metulhtcter  Bacillus,  which  it  much  re-  \  containing  Chara  and  Lemna,  from 
sembles ;  yet   is  always   non-articulate,  i  various  Swiss  localities. 


538  ■  SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 

In  Ehrenberg's  system  the  family  Closterina  follows  here,  but  in  this  edi- 
tion it  is  transferred  to  the  Desmidieae,  of  which  it  constitutes  an  important 
genus.     (See  Part  I.  p.  1  et  seq.) 

FAMILY  VI.— ASTASLEA  oe  EUGLEN^A  (see  p.  188). 

(XYIII.  35-56  ;  XX.  15-21). 

The  members  of  this  family  are,  according  to  Ehrenberg,  characterized  by 
being  deficient  of  a  true  alimentary  canal  and  lorica,  and  by  having  a  single 
aperture  and  the  power  of  changing  their  form  at  pleasiu'e.  Theii^  organs 
of  locomotion  consist  of  a  tail  in  most  cases,  a  single  filament  in  three  genera, 
and  a  double  one  in  a  fourth.  It  is  probable  that  filaments  exist  also  in  the 
other  two  genera,  Colacium  and  Distigma.  The  internal  vesicles  were  pre- 
sumed to  be  gastric  sacs,  although  the  usual  test  of  their  being  so,  viz.  the 
application  of  coloured  food,  failed  in  Ehrenberg's  hands ;  yet,  he  says,  he 
noticed  some  manifestations  of  a  digestive  power  in  the  green  and  red  cells  of 
Euglena  viridis.  In  Euglena  there  are,  besides  green  ova  (granules),  a  gland 
(nucleus)  and  a  contractile  vesicle  ;  but  Astasia,  Distigma,  and  Colacium  ex- 
hibit only  ova.  Large  red  points  are  found  in  five  genera.  In  Euglena 
longicauda  and  E.  amhlyophis,  adds  Ehrenberg,  "  the  first  indication  of  the 
presence  of  nervous  matter  to  be  found  in  the  polygastric  Infusoria  "  is  met 
with  in  the  form  of  a  white  glandular  knot,  situated  below  the  eye. 

The  following  table  illustrates  the  characters  of  the  genera  of  this  family 
as  instituted  by  Ehrenberg : — 

Eye  wanting 


Eye  present 


Free 
With  one  eye 


With    one  f  ^^"^  wanting Amblyopliis. 

proboscis  I  ^^.j  ^^^^^^^^  Wxglen^. 


^  With  two  proboscides Chlorogonium. 

(^  Attached  by  a  pedicle  Colacium. 

^  With  two  eyes  Distigma. 

The  family  Euglenaea  (Eugleniens)  of  Dujardin  in  a  great  measure  corre- 
sponds Avith  that  of  Astasiaea  of  Ehrenberg;  but  Dujardin  prefers  the  term 
Euglenaea,  on  account  of  the  resemblance  of  the  other  name  to  that  of  a 
family  of  Crustaceans,  viz.  the  Astaciaea. 

Dujardin  looks  upon  the  so-called  eyes  as  insufficient  to  afford  generic 
characters,  which  he  would  derive  from  the  nature  or  apparent  structure  of 
the  integument,  and  the  number  and  mode  of  insertion  of  the  filaments.  On 
these  principles  he  establishes  a  genus  Polyselmis,  characterized  by  its  many 
filaments ;  two  genera,  Zygoselmis  and  Heteronema,  by  a  paii'  of  filaments,  in 
the  former  of  equal,  in  the  latter  of  unequal  size.  The  remaining  Euglenaea, 
which  have  but  a  single  filament,  can  be  but  uncertainly  defined :  such  are 
the  Euglena^,  mostly  coloured,  and  having  a  red  eye-speck  and  a  tail ;  the 
Astasice  without  colour  and  tail,  but  with  a  filament  flexible  throughout,  and 
springing  abruptly  from  a  notch  in  the  anterior  extremity ;  and  the  PeranemcB 
only  diff'ering  from  the  Astasice.  in  having  a  filament  rigid  at  the  base,  and 
apparently  a  continuation  of  the  tapering  anterior  extremity  of  the  animalcule. 
The  two  last  genera  are,  however,  but  provisional. 

Astasiaea  is  one  of  the  families  in  the  group  of  Phytozoidia  of  Perty,  who 
ignores  the  genera  Amhlyopliis  and  Distigma  of  Ehrenberg,  adopts  the  Pera- 
nema  and  Zygoselmis  of  Dujardin,  and  adds,  as  new  genera,  Eutreptia  and 


OF  THE  ASTASIiEA  OK  EUGLEN^A.  539 

Dinema.  Again,  Schneider  (A.  N.  II.  1854,  xiv.  p.  327)  would  separate 
Chlorogonium  from  the  Astasiaea  on  account  of  its  unchangeable  form,  and  Mr. 
Carter  {A.  N.  H.  1856,  x\iii.  p.  116,  and  1859,  iii.  p.  15)  would  refer  Euglence 
to  the  vegetable,  and  Astasice  to  the  animal  kingdom.  The  differences  pre- 
vailing among  natm^ahsts  relative  to  the  beings  to  be  admitted  into  the  family 
Astasiaea  indicate  either  that  its  characters  are  not  laid  down  with  sufficient 
precision,  or  that  it  is  not  a  natural  group.  The  power  to  vary  the  figure 
can  be  no  adequate  character ;  for  this  is  partaken  by  the  gonidia  of  various 
Algae  in  certain  amoebiform  stages  of  existence,  and,  on  the  other  hand,  is 
absent  in  some  species  enumerated  by  Ehrenberg  in  the  genus  EugJena,  as 
well  as  in  Chlorogonium.  The  tapering  or  tail-like  prolongation  of  one  ex- 
tremity, the  existence  of  one,  two,  or  more  ciliary  filaments,  as  also  of  a  red 
speck,  are  likewise  features  common  to  numerous  zoospores.  Even  when 
appeal  is  made  to  their  internal  organization  and  functions,  nothing  appears 
whereon  the  definite  characters  of  a  natural  family  can  be  built.  Eor,  on  the 
one  hand,  the  organization  assigned  them  by  Ehrenberg  is  now  held  to  be 
untenable,  and,  on  the  other,  no  harmony  prevails  resj^ecting  the  internal 
structure  as  recorded  by  different  observers  of  the  various  genera.  Mr. 
Carter,  in  the  paper  just  quoted,  states  unhesitatingly  that  most  of  the 
Astasia  enumerated  by  Ehrenberg  are  animal  forms,  whilst  the  Eiigleme 
are  vegetable.  He  remarks  that,  "  although  no  two  Infusoria  can  be  more 
alike  than  Astasia  limpida  and  Euglena  when  casually  observed ....  yet  the 
absence  of  chlorophyll  and  the  presence  of  a  stomachal  cavity,  &c.  for  the 
digestion  of  crude  food  in  the  former,  and  the  presence  of  chlorophyll  and 
absence  of  a  stomachal  cavity,  as  weU  as  of  all  means  of  taking  in  crude  food 
for  digestion,  in  the  latter,  are  distinguishing  characters  which  at  once  place 
Astasia  limpida  on  the  animal,  and  Euglena  on  the  vegetable  side,  respectively, 
of  the  great  organic  kingdom ;  yet  both  Ehrenberg  andDujardin  have  classed 
Astasia  and  Euglena  together." 

If  the  organic  difference  between  Astasice  and  Euglence  be  what  Mr.  Carter 
asserts,  his  proposition  to  divide  the  Astasiaea  of  Ehrenberg  into  two  families, 
viz.  Astasiaea  and  Euglenaea,  must  be  accepted. 

The  Astasiaea  inhabit  ponds,  mostly  occurring  on  the  sui^face,  and  frequently 
tinge  the  water  with  their  own  colour  when  their  multiplication  has  been 
very  rapid.  WTien  swimming,  they  present  an  elongated  form,  but  when 
fixed,  often  appear  as  round  globules.  From  their  beautiful  colour,  their 
ever  varying  changes  of  form,  and  the  rapidity  of  some  of  their  \ital  acts, 
they  are  most  interesting  and  pretty  objects  under  the  microscope,  and  from 
their  common  occurrence  are  almost  always  at  hand  for  the  student.  Many 
are  capable  of  progressing  by  alternately  fixing  and  advancing  the  head  and 
tail  after  the  manner  of  a  leech,  as  well  as  by  the  usual  process  of  swimming. 

Genus  ASTASIA  (XYIII.  36,  48, 49,  50).— Individuals  free  (not  attached 
by  a  pedicle),  and  fm^nished  with  a  long  or  short  tail,  but  no  eye-specks.  A. 
pusilla  is  the  only  species  in  which  vacuoles  have  been  clearly  seen.  Ova 
(granules)  are  perceptible  in  A.  hwmatocles,  and  probably  exist  in  the  three 
other  species  ;  a  locomotive  organ  in  the  form  of  a  thread-hke  proboscis  exists 
in  A.  pusilla.  Perty  unites  this  genus  with  Distigma.  The  immense  num- 
bers in  which  these  Infusoria  are  sometimes  developed  in  a  few  days,  and  the 
blood-red  coloiu"  they  impart,  have  not  unfrequently  been  the  cause  of  con- 
siderable alarm  and  anxiety  to  persons  residing  in  the  vicinity  of  ponds  or 
small  lakes  which  have  become  blood- coloured  by  their  swarming. 

Dujardin's  genus  Astasia  is  defined  as  colourless,  obtuse  or  rounded  poste- 
riorly ;  whilst  those  described  by  Ehrenberg  are  mostly  green  or  red,  and 
pro\^dcd  with  a  longer  or  shorter  caudal  prolongation. 


540 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Astasia  hcsmatodes  (xvni.  86,  two 
figs.). — Body  fusiform  or  spindle-shaped 
when  extended j  tail  very  short;  body 
green  at  first,  afterwards  of  a  blood-red 
colour.  The  illustrations  represent  one 
creatiu'e  extended,  and  another  con- 
tracted. Hampstead.  1-380".  This  spe- 
cies is  referred  by  Dujardin  and  Carter  to 
the  genus  Euylena. 

A.  Jlavicans.  —  Extensible,  cone- 
shaped,  approaching  cylindrical,  and 
rounded  at  the  foremost  extremity.  Tail 
very  short  and  blunt;  granules  of  a 
yellowish  colour.  In  yellow  ditch- 
water.     Length  about  1-430". 

A.  pusilla. — Extensible,  cone-shaped, 
swelling  out  and  rounded  at  the  fore 
extremity,  tail  very  short  and  pointed ; 
colourless.  Motor  filaments  above  t^nce 
the  length  of  the  body.  Movements 
slow;  but  rotation  on  the  longitudinal 
axis  rapid.  Several  phases  of  Euglena 
viridis  resemble  this  species  in  form, 
molecular  arrangement  of  contents,  size, 
and  motion,  and  are  peculiar  only  on 
account  of  their  green  colour  and  red 
stigma.  Ehrenberg  remarks  that  they 
are  often  so  abundant  that  thousands, 
perhaps  millions,  of  these  creatures  are 
sometimes  contained  in  the  hollow  of  a 
watch-glass,  and  form  a  stratum  on  the 
surface  of  the  w^ater.  They  might  be 
mistaken  for  the  young  of  the  A.  fia- 
vicmis,  but  that  the  vesicles  within  them 
are  larger  than  those  in  that  species, 
which  is,  moreover,  without  proboscis. 
As  soon  as  a  little  colouring  matter  was 
thrown  into  the  water,  an  evident  cur- 
rent was  observed  near  the  fore  part  of 
the  creature ;  and  by  this  means,  in  1833, 
the  thread-like  filament,  which  is  about 
half  the  length  of  the  body,  was  first 
perceived.  Sometimes  the  entire  crea- 
ture appears  to  glisten.  Shoidd  this 
species,  upon  closer  inspection,  be  found 
to  be  ciliated,  it  would  be  rightly  placed 
among  Peridiniaea.  1-1440"  to  1-500". 
The  size  of  the  vesicles  remarked  by 
Ehrenberg  is  no  distinctive  character;  and 
Mr.  Carter  believes  that  both  this  species 
and  A.  Jlavicans  are  either  identical  with 
or  very  nearly  allied  to  A.  limpida,  and 
therefore  animal  organisms,  unlike  the 
EiajlencB,  to  which  they  have  a  generaF 
resemblance. 

A.  (?)  viridis.  —  Extensible ;  of  an 
ovate-oblong  form,  distended  a  little  at 
the  middle ;  tail  very  short  and  pointed  ; 
green.  Amongst  Confervas.  1-1200" 
to  1-900".  This  species  and  A.  h(pma- 
todes  are,  in  Dujardin's  opinion,  members 
of  the  genus  Euyloia,  the   only  appre- 


ciable diiference  between  them  being  the 
presence  of  a  red  stigma  in  this  genus. 
In  this  opinion  Mr.  Carter  coincides. 

A.  nivalis  (Vogt)  (x^^I.  532-533).— 
Oval,  extremities  roimded,  rarely  pear- 
shaped,  colour  deep  reddish-brown,  mo- 
tion rapid.  Found  with  Protococcus  ne- 
hulosus  in  snow  (Switzerland).  1-1500". 
M.  Vogt,  in  liis  accoimt  of  the  Astasia 
nivalis,  describes  it  as  invested  with  a 
carapace  (lorica),  open  only  at  the  an- 
terior extremity.  This  opening  is  fur- 
nished with  numerous  small  cilia ;  and 
here,  doubtless,  the  mouth  is  situated, 
the  indication  of  which  is  given  by  an 
orange-coloured  tint,  which  is  clearer 
than  that  of  the  rest  of  the  animal. 
"The  presence  of  a  lorica  and  cilia 
affords  a  character  which  does  not 
allow  this  animalcule  to  be  placed  with 
Astasia,  as  Shuttlew^orth  has  done;  on 
the  contrary,  it  ought  to  be  placed  in 
the  family  Peridiniaea  (Ehr.),  or  else  be 
regarded  as  the  type  of  a  new  genus, 
distinguished  by  the  absence  of  a  groove 
in  the  lorica,  and  by  the  stiff"  hairs  of 
Peridinium  being  replaced  by  soft  cilia." 
(On  the  Animalcules  of  the  Red  Snow, 
Bihl.  Univ.  de  Geneve,  1841.)  This  pre- 
simied  species  is,  in  all  probability, 
nothing  more  than  an  encysted  cor- 
puscle, probably  a  species  of  Chlamy- 
dococcus. 

A.  Acus. — Hyaline,  figure  long-fusi- 
form, acute  at  each  end ;  filament  the 
length  of  the  body.  1-650".  Berlin. 
Under  the  head  Astasia,  Perty  enume- 
rates the  following  species ;  but,  as  he 
makes  no  distinction  between  Astasia 
and  Distigma,  the  generic  appellation  is 
not  quite  equivalent  to  that  used  by 
Ehrenberg. 

A.  margaritifera  (Smarda). — Remark- 
able by  its  variability  of  form,  or  meta- 
bolia,  the  contents  appearing  to  be  driven 
from  one  part  to  another,  filling  and  dis- 
tending one  portion,  whilst  the  other  is 
left  empty  and  contracted.  Hyaline 
granules  (germs?)  very  distinct.  At 
periods  it  loses  its  filaments,  and  with 
them  its  powers  of  swimming,  when  it 
adopts  a  crawling  movement.  Two 
clear  spots  occur  near  the  base  of  the 
filament,  which  is  once  and  a  half  to 
t\vice  the  length  of  the  body:  these 
spots  were  called  eyes  by  Ehrenberg, 
who  made  them  the  distinctive  feature 
of  a  genus  Distigma.  In  pond-water, 
and  even  under  ice,  but  not  common. 
A  variety,  much  elongated  and  slender, 
has  been  called  Astasia  Serpetituhis. 


OF  THE  ASTASIA  A  OR  EUGLEJ^^A. 


541 


The  following  species  are  described  by  Dujardin  : — 


A.  coiitorta  (x^^II.  49,  50). — Colour- 
less, semi-transparent,  containing  pale- 
yellow  granules ;  cylindroid,  enlarged  in 
the  middle,  obtuse  at  each  end,  and 
marked  with  oblique  striae,  giving  rise 
to  a  twisted  appearance.  1-450".  In 
sea-water. 

A.  injlata.  —  Semi-transparent,  dia- 
phanous, contractile,  ovoid,  obliquely 
but  regularly  plaited  or  striated.  1-560". 
In  sea- water. 

A.  Umpida  (xviii.  48  a,  h,  c).  —  Dia- 
phanous, smooth,  very  variable,  fusiform, 
more  or  less  obtuse  at  each  end,  cleft 
anteriorly,  and  often  obliquely  doubled 
on  itself  or  twisted.  1-650"  to  1-530". 
In  ditch-water.  Perty  remarks  that 
Dujardin  is  \\Tong  in  identifjdng  Astasia 


pusilla  and  A.Jlacicaus  with  this  species. 
Mr.  Carter  (A.  N.  H.  1859,  iii.  p.  15)  treats 
this  organism  as  an  undoubtedly  animal 
fomi,  and  describes  it  as  having  a 
stomach  or  digestive  cavity,  into  which 
it  receives  food  from  without.  Unlike 
Euglena,  which  it  outwardly  resembles, 
it  contains  no  chlorophyll.  He  also  con- 
siders that  it  is  the  same  being  which 
Ehrenberg  has  described  and  hgiired  as 
Trach elius  tinchophorus. 

A.  longijilis  (Perty). —  Hyaline,  with 
pale-green  internal  granules ;  filament 
at  least  three  times  longer  than  the 
body  :  a  lateral  plait  or  figure  is  seen  in 
the  anterior  half  Form  imchangeable. 
Motion  tolerably  fast.     1-1000". 


Genus  AMBLYOPHIS  (XVIII.  45). — Free,  with  a  single  eye-speck  and 
flabellum,  but  no  tail.  The  flabellum  or  filament  serves  as  an  organ  of 
locomotion,  and  is  situated  at  the  fore  extremity,  which,  says  Ehrenberg,  is 
cleft,  so  as  to  represent  a  two-lipped  mouth,  the  filament  being  very  readily 
distinguished  on  the  upper  lip.  The  colour  of  the  animalcule  is  derived  from 
the  closely  compressed  mass  of  green  granules,  which  nearly  fills  the  body. 
Near  the  middle  of  the  creature  is  a  large,  bright,  globular,  together  with  five 
wand-like  bodies,  two  of  which  are  situated  before,  and  three  behind  the 
former ;  these  structures  together  were  supposed  to  be  male  generative  organs. 
No  contractile  vesicle  has  been  observed.  Self-division  is  unknown.  The 
coloiu-ed  speck  is  very  highly  developed.  Towards  the  anterior  part  of  the 
body,  and  just  behind  the  filament  where  the  mass  of  granules  commences, 
there  is  a  bright-red  and  somewhat  lengthened  spot  (resembling,  as  to  situ- 
ation and  colour,  the  eye  of  the  Rotatoria  and  Entomostraca),  in  the  clear 
space  beneath  which  is  a  mass  of  matter  of  a  very  peculiar  description,  of  a 
globular  form,  having,  to  Ehrenberg's  apprehension,  the  appearance  of  a 
nervous  ganglion,  and  being  most  probably  connected  vdih.  the  organ  of 
vision.  This  genus  is  not  distinct  from  Eiof/Iena  ;  for  the  absence  of  the  so- 
called  tail  is  insufficient  to  distinguish  it,  and,  what  is  more,  Perty  has  seen 
AmhJyopMs  viridis  proceed  from  Euglena  viridis  in  the  process  of  reproduction. 


Amblyophis  vindis  (xviii.  45).  — 
Large,  elongated,  cylindrical,  distended 
or  compressed,  and  abruptly  rounded  at 
the  posterior  extremity ;  gi-een,  head 
colourless :  eye -speck  large,  bright  red. 
The  motion  of  this  creature  is  sluggish 


and  sei-pentine,  and  by  its  evolutions 
might  easily  be  mistaken  for  the  Euglena 
Spirogyra,  were  that  creature,  like  this, 
tailless.  Found  with  Euglence^  chiefly 
in  the  spring.  1-210"  to  1-140"  (vide 
p.  194). 


Genus  EUGLENA  (XVIII.  37-44,  46,  51,  52,  54).— This  beautiful  genus 
of  the  family  Astasiaea  is  characterized  by  being  furnished  with  an  eye,  a 
single  thread-like  filament,  and  a  tail,  and  by  being  free.  The  locomotive 
filament  is  seen  in  nine  species  out  of  the  eleven,  and  has  a  double  appearance, 
in  E.  sangidnea  ascribed  to  the  condition  of  the  animalcule  preparatory  to 
seK-division.  In  Euglena  liyalina,  E.pleuronectes,  and  E.  longicauda,  vacuoles 
are  generally  visible  ;  but  in  the  other  species  they  are  obscured  by  the  masses 
of  green  granules  which  colour  their  bodies.  Certain  internal  appearances 
have  been  recognized,  which  Ehrenberg  supposed  to  be  of  a  male  generative 


542 


SYSTEMATIC  HISTORY  OF  THE  mrrSOHIA. 


nature,  ?*.  e.  a  nucleus.  Longitudinal  self-division  has  been  observed  in  E. 
Acus,  and  the  commencement  of  it  in  E.  sanguinea  (XVIII.  37-39).  Close  to 
the  red  point  a  supposed  nervous  ganglion  or  eye-speck  is  visible  in  E.  longi- 
cauda  (XVIII.  44),  such  as  is  seen  in  AmhlyopJiis.  The  genus  Euglena  of 
Ehrenberg,  saysDujardin,  contains  some  species  of  a  compressed  leaf-like  form, 
and  quite  deficient  of  contractility,  which  require  to  be  placed  in  the  genus 
Phacus  of  the  family  Thecamonadina. 


Euglena  sanguinea  {Cercaria  viridis, 
M.)  (x\^n.  37-39). — Extensible,  of  an 
oblong-cylindrical  or  spindle-shaped 
form,  with  head  greatly  rounded ;  tail 
short,  conical,  and  somewhat  pointed. 
Flabelluni  longer  than  the  body  in  its 
extended  condition.  When  yoimg,  they 
are  green,  but  when  fiill-gTown,  of  a 
blood-red  colour;  and  specimens  are 
frequently  foimd  variegated  red  and 
green.  The  motion  of  this  multiform 
animalcule  is  generally  slow ;  and  it 
sometimes  revolves  upon  its  longitudinal 
axis  in  swimming.  The  thread-like  fila- 
ment, which  is  a  prolongation  of  the 
upper  lip,  and  rather  longer  than  the 
body,  is  so  delicate  as  to  require  consi- 
derable care  in  investigating  it,  and, 
being  reti'actile,  wiU  often  elude  obser- 
vation. A  little  colouring  matter  in  the 
water  will  exhibit  this  organ  in  active 
operation ;  and  it  may  be  distinctly  seen 
in  a  single  animalcule  in  a  dried  state, 
upon  a  plate  of  clear  glass.  The  double 
appearance  of  the  organ  in  this  species 
has  been  before  noticed.  Ehrenberg 
conjectured  that  the  miracle  in  Eg>q)t, 
recorded  by  the  great  lawgiver  of  the 
Jews,  of  turning  the  water  into  blood, 
might  have  been  effected  by  the  agency 
of  these  creatures,  or  by  the  Astasia 
hmnatodes.  In  stagnant  water,  often  in 
great  abundance  on  the  surface.  1-300" 
to  1-210".  This  is  in  all  probability  a 
mere  variety  of  E.  viridis ;  the  red 
colour  is  not  a  specific  distinction,  but 
only  a  sign  of  maturity. 

E.  hyalina. — Extensible  in  a  spindle- 
shaped  manner;  head  attenuated,  blunted 
at  the  extremity,  and  two-lipped ;  tail 
short,  and  somewhat  pointed;  001010* 
transparent  and  whitish  ;  rare.  1-280". 
Perty  asserts  that  it  is  only  a  variety  of 
E.  viridis. 

E.  dcses  (Encheli/s  deses,  M.). — Extensi- 
ble, cylindrical,  abruptly  rounded  at  the 
head,  and  slightly  bi-lipped.  Tail  very 
short  and  pointed ;  colour  gi'een ;  motion 
a  winding  and  sluggish  creeping,  never 
swimming.  Filament  very  long  and  fine. 
Amongst  Lemnte.     1-240"  to  1-760". 

E.  viridis  {Cercaria  viridis,  M.)  (xviii. 
40).  —  Extensible  in   a    spindle-shaped 


manner;  head  attenuated  and  short. 
Tail  short,  and  cone-shaped,  not  cleft; 
colour  ^Teen,  excepting  the  two  ex- 
tremities, which  are  colomless.  The 
double-pointed  tail  represented  by  Leeu- 
wenhoek  and  others  does  not  exist. 
When  the  creatm^e  is  young,  its  eye- 
speck  is  imperceptible  or  very  pale, 
and  it  may  readily  be  mistaken  for 
Astasia  viridis  or  3Ionas  deses.  When 
dried  on  glass,  the  speck  seldom  retains 
its  colour  more  than  a  week;  but  the 
filament  may  be  well  examined  and  pre- 
served when  so  treated.  Filament  twice 
the  length  of  the  body,  which  differs 
very  much — between  1-600"  and  1-140". 
Perty  affirms  that  E.  lixjalina  is  a  mere 
variety  of  this  species,  and  that  Am- 
hly aphis  viridis  (x\t:ii.  45)  is  the  same, 
for  he  has  witnessed  the  same  individual 
Euglena  produce  both  Euglena  and  Am- 
bli/ophis.  This  observer  has  found  E. 
viridis  at  an  elevation  of  9000  feet,  on 
the  Alps.  On  the  surface  of  ponds  at 
Hampstead  and  elsewhere,  common. 

E.  Spirogyra  (x\t:ii.  52). — Extensible 
and  cylindrical ;  very  finely  striated  and 
granulated.  The  head  is  a  little  trim- 
cated,  and  the  hinder  part  attenuated 
into  a  short  pointed  tail;  colom'  a 
brownish  green ;  motion  like  E.  deses. 
Its  colour  varies  from  a  beautiful  green 
to  yellow  or  brown.  It  always  occurs 
singly.  E.  oxyuris  (Smarda)  is  not 
specifically  distinct.  Amongst  Confervas 
and  Bacillaria.     1-240"  to  1-120". 

E.  Pyrmn  (xvin.  41,  42). — Obliquely 
fluted:  when  distended,  oval  or  pear- 
shaped.  The  tail  generally  about  the 
length  of  the  body,  and  pointed ;  colour 
green.  Found  with  many  other  species  at 
Hampstead,  but  not  so  frequently  as  the 
other  species.     1-1152"  to  1-864". 

E.  2)leuronectes  ( Cercaria  p)letironectes, 
M.).  —  Compressed,  ovate-orbicular,  or 
in  the  form  of  an  obovate  leaf;  striated 
longitudinally;  colour  green;  tail  pointed, 
one-third  or  one-fourth  part  the  length 
of  the  body,  and  colourless.  In  stagnant 
water.     1-1152"  to  1-480". 

E.  longicauda  (xviii.44). — Mostly  stiff, 
compressed,  elliptical,  and  leaf-like  ;  co- 
lour green  ;  tail  the  length  of  the  body. 


OF  THE  ASTASI^A  OR  EUGLENiEA . 


543 


awl-shaped  and  colourless.  Within  this 
creatiu'e  may  often  be  seen  a  yello\visli- 
gi"een  mass  of  granules.  The  very  deli- 
cate vibrating  thread-like  filament  has 
its  origin  from  the  more  projecting  side 
of  an  indentation  on  the  anterior  edge  of 
the  body,  and  is  about  two-thirds  its 
length.  '  This  creature  has  the  power  of 
twisting  its  body  into  a  spiral  form,  but 
not  of  contracting  it.  It  swims  freely, 
and  mostly  with  a  vibratory  motion, 
occasioned  by  the  action  of  the  filament. 
In  fresh-water  amongst  Conferv'se  and 
BacUlaria.     1-480"  to  1-120". 

E.  triquetra.  —  Leaf-shaped,  three- 
sided,  oval-keeled ;  colour  green ;  tail 
shorter  than  the  body,  and  colom-less. 
Amongst  Lemnae.     1-580". 

E.  Aciis  {Vibrio  Acus,  JM.). — Slender, 
spindle-shaped,  and  straight ;  head  atte- 
nuated, and  a  little  truncated  -,  tail  very 
pointed ;  body  gTeen  in  the  middle,  and 
colourless  at  the  extremities.  This  is  one 
of  the  most  beautifid  animalcides  seen 
under  the  microscope ;  its  graceful  form 
when  swimming,  its  bright-red  eye,  the 
curious  forms  it  assumes  when  stationary, 
and  its  remarkable  appearance  when  im- 
dergoing  self-division,  all  combine  to 
render  it  worthy  of  observation.  Fresh 
and  brackish  water.     1-570"  to  1-110". 

E.  rostrata. — Elongated  and  conicail, 
with  the  hinder  part  gradually  attenu- 
ated into  a  very  short  tail.   Head  slightly 


bent,  like  a  beak ;  colour  gTeen.  Amongst 
OscillatorifB  and  BaciUai'ia.  Length 
about  1-500". 

E.  Ovum. — Ovate,  green,  with  a  very 
short  hyaline  caudal  prolongation,  and  a 
large,  double,  circular  nucleus.  1-1560". 
Berlin. 

E.  geniculata  (D.). — Green,  elongated, 
cylindrical,  flexible  but  not  very  con- 
tractile ;  movement  slow ;  tail  tapering, 
clear,  and  at  an  angle  with  the  body — 
hence  the  name.  1-208"  to  170".  This 
large  Euglena  is  remarkable  by  its  elong- 
ated form,  by  its  diameter  being  nearly 
equal  to  its  length,  without  the  bulging 
of  E.  viridis,  and  by  its  articulated  tail. 

E.  ohscura{D.'). — Thick,  oblong;  dis- 
tended and  obtuse  posteriorly;  but  the 
fonu  very  variable  ;  clearer  and  of  a  red 
tint  anteriorly,  eye-speck  reddish-black  ; 
filament  half  as  long  again  as  the  body. 
1-870".  This  form  Perty  sm-mises  to  be 
only  a  deeper-coloured  specimen  of  E. 
sanguijiea,  which  he  often  found  of  a 
brown  or  blackish-red  colour. 

E.  mucronata  (Pertj'). — Of  a  beautiful 
green  colour,  the  anterior  segment  or 
head  frequently  hyaline,  with  a  clear-red 
stigma;  tail  pointed  and  transparent. 
Body  oval,  often  longitudinally  and 
finely  striped.  Filament  overlooked. 
Difters  from  E.  geniculata  by  the  absence 
of  the  angularly-set  filament.  1-108"  to 
1-84". 


Mr.  Carter  describes  the  following  new  species  from  tlie  freshwater  tanks 
of  Bombay : — 


^.  fusiformis. — Short,  thick,  fusiform, 
obtuse,  of  a  rich  green  colour,  provided 
with  a  long,  delicate,  single  cilium,  which 
projects  from  a  slightly  bilabiate  anterior 
extremity;  a  little  behind  which  is  the 
eye-spot,  attached  to  the  contracting 
vesicle.  Nucleus  central,  situated  be- 
tween the  ends  of  two  elongated,  refrac- 
tive, nucleated  cells,  which  extend  round 
the  body  equatorially.  Tailless.  Motion 
during  progression  oscillatory,  and  rotat- 
ing on  the  longitudinal  axis.  Length 
about  1-700",  breadth  about  1-1100". 
Freshwater  tanks  in  the  island  of 
Bombay. 

E.  zonalis. — Short,  thick,  ovoid  cylin- 
drical, slightly  naiTowed  anteriorly,  of  a 
rich  green  colour ;  provided  with  a  long 
delicate  cilium,  which  projects  from  the 
notch  of  a  slightly  bilabiate  anterior  ex- 
tremity ;  a  little  behind  which  is  the  eye- 
spot,  attached  to  the  contracting  vesicle. 


Nucleus  central,  between  the  ends  of  two 
wide,  refractive,  nucleated  cells,  which 
extend  round  the  body  equatorially.  Tail 
adhesive  or  suctorial  (?),  short,  about 
one-sixth  part  of  the  length  of  the  body. 
Motion  during  progression  oscillatory 
and  rotating,  on  the  long  axis  of  the  body. 
Length  l-llOO",breadth  1-1800".  Fresh- 
water tanks  in  the  island  of  Bombay. 

These  two  Euglejice  are  remarkable  for 
having  that  refractive  cell  or  organ  which 
I  have  called  the  "  glair-cell  "  equatorial, 
instead  of  longitudinal  as  in  Euglena 
Spirogyra,  or  single  and  in  the  anterior 
lip  as  in  Crumenula  tcxta. 

E.  agilis. — Is  a  third  species  Mr.  Carter 
would  distinguish  ;  but  he  has  given  no 
details,  except  relative  to  its  develop- 
ment in  the  still  form.  1-600".  In  the 
brackish  waters  of  the  marshes  of  Bombay 
{A.  N.  H.  1856,  xviii.  p.  246). 


Genus  CHLOROGONIUM  (p.  195)  (XYIII.  47 ;  XX.  \b-21). —Asiasice 


544 


SYSTEMATIC  HISTOKY  OF  THE  INFUSORIA. 


with  a  double  filament.  Are  free  and  provided  with  an  eye-speck,  tail,  and 
double  filament.  The  only  known  species  is  of  a  very  beautiful  green  colour, 
and  has  numerous  transparent  vesicles  within  it.  A  distinct,  hyaline  nucleus 
is  perceptible  in  the  centre  of  the  animalcule.  Self- division  of  the  contents 
into  four  or  more  segments  has  been  observed  to  take  place,  also  propagation 
by  microgonidia.  Schneider  and  Perty  conciu*  respecting  the  propriety  of 
detaching  Chlorogonium  from  the  Astasisea.  Numerous  dull-red  specks  are 
scattered  throughout  its  green  contents,  no  one  of  which  has  the  clearness 
and  distinctness  of  the  stigma  of  Euglence.  The  primordial  envelope,  with  its 
enclosed  green  contents,  varies  in  figure ;  but  not  the  external  one,  which  is 
rigid. 


Chlorogonium  euchlorum  (xviii. 
47  ;  XX.  15-21). — Spindle-shaped,  verj^ 
pointed  at  both  extremities ;  tail  short ; 
colour  sparkling  green.  The  eye-speck 
is  so  delicate  that  it  may  be  easily  over- 
looked ;  but  when  the  creature  is  dried 
upon  a  plate  of  very  clear  glass,  both  the 
eye  and  the  double  filament  are  readily 
seen,  and  it  may  be  preserved  as  a  per- 
manent microscopic  object,  x^aii.  fig. 
47  represents  a  cluster  of  six,  each  with 
its  double  proboscis.  In  water-butts,  on 
ponds,  &c. ;  it  forms  the  green  matter  of 


Priestley.  1-110' 
of  the  tail.  It  was  in  this  species  that 
M.  Weisse  thought  he  had  discovered  a 
form  of  propagation  analogous  to  that  by 
ova,  but  in  fact  to  reproduction  by  mi- 
crogonidia (xx.  15-21).  The  young 
forms  so  produced,  especially  in  their 
aggregate  state  before  discharge,  re- 
semble JJvella  Bodo\  and  M.  Weisse 
thinks  Chlorogonium  eiwklorum  and 
Glenomorum  tingetis  only  other  stages  of 
development  of  the  same  organism. 


Genus  COLACIUM. — Eye-speck  or  stigma  single.  Filament  not  detected 
in  this  genus,  although,  as  Ehrenberg  remarks,  there  can  be  no  doubt  of  its 
existence,  from  the  currents  which  are  \dsible  in  coloured  water  near  the 
forepart  of  the  body ;  still,  as  these  are  rather  feeble,  it  is  probable  that  the 
organ  is  but  single.  Numerous  transparent  vesicles  are  seen  within  the  body. 
The  creatures  are  parasitical  upon  Entomostraca  and  Rotatoria,  to  which  they 
attach  themselves  by  means  of  a  pedicle  or  footstalk,  which  is  single  at  fii-st, 
but  becomes  ramified  by  the  process  of  self- division. 

Found    upon    Entomostraca.      1-860". 


CoLACiUM  (P)  vesiculosum. — Spindle- 
shaped,  oval,  but  variable  ;  pedicle  very 
short,  and  seldom  ramified;  colour 
sparkling  green,  with  distinct  internal 
vesicles.  Ehrenberg  says,  "  I  have  again 
sought  in  vain  for  the  red  eye  (May  23, 
1835),  but  cannot  be  satisfied  of  its  uon 


upon 

C.  stentorinum.  —  Form  variable,  but 
somewhat  cylindrical,  prolonged  anteri- 
orly into  a  funnel-shaped  process ;  colour 
beautifid  green ;  vesicles  indistinct;  pedi- 
cle often  ramified.  The  eye-speck  is  at 
one  time   distinct,  at  another  scarcely 


existence,  as  it  is  imdoubtedly  present    perceptible ;  it  differs  also  in  position  so 


in  the  other  species,  and  investigation 
is  sometimes  improductiAe  on  account 
of  subordinate  circumstances.  I  have 
likewise  failed  in  seeing  very  satis- 
factorily the  vibratory  organ,  notwith- 
standing its  action  is  evident  enough." 


widely  that  sometimes  it  is  close  to  the 
elongated  neck,  at  others  near  the  poste- 
rior end.  Perty  siumises  it  to  be  a  larval 
condition  of  some  other  being,  or  merely 
a  sporozoid.  Found  upon  Entomostraca 
and  Polyarthra  trigla.     1-1150". 


Genus  DISTIGMA. — Astasice_  with  two  eye-specks.  Locomotive  organs 
not  hitherto  discovered  ;  and  the  presumption  is  that  they  do  not  exist ;  none 
of  the  species  either  s^vim  or  produce  perceptible  cuiTents  in  coloured  water. 
Movements  creeping  or  crawling,  much  like  those  of  eels ;  form  variable,  like 
that  of  Lacrymaria;  and  they  approximate  to  Amoeba  in  other  respects, 
besides  the  absence  of  a  flabellum.  At  the  fore  part  of  the  body  may  be 
seen  two  very  delicate,  blackish -coloured  spots,  analogous  to  the  eye-specks 
in  other  genera.      The   Distigmo'  are  sometimes   confounded  ^^dth  Vrotevs 


OF  THE  ASTASIA  A  OE  EFGLEN^A. 


545 


cliMuens  of  Miiller.  All  the  species  are  exquisite  objects  for  a  deep-powered 
microscope — for  instance,  one  magnifying  460  diameters.  Perty  unites  this 
genus  with  Astasia,  as  being  indistinguishable  from  it  by  any  sufficient  charac- 
teristics. 


DiSTiGMA  tenax  {ProUus,  M.). — Larger 
than  either  of  the  other  species ;  proteus- 
like— at  one  time  greatly  distended,  at 
another  as  much  consti-icted ;  eye-speck 
rather  indistinct ;  colour  transparent  yel- 
low. About  liCmnse.  1-240".  This  spe- 
cies Perty  regards  as  merely  a  larger 
variet}^  of  Astasia  margaritifera,  inca- 
pable of  the  same  extent  of  metabolia. 

D.  Proteus  (Proteus, ~M.). — Smaller  than 
the  preceding ;  proteus-like — sometimes 
greatly  distended,  at  others  constricted ; 
blunted  at  both  extremities ;  eye-specks 
distinct.  Amongst  Confervae.  1-580"  to 
1-400".  This  species,  says  Perty,  appears 
nothing  else  than  a  smaller  specimen  of 
Astasia  margaritifera  which  has  lost,  to 


a  greater  or  less  extent,  its  filaments,  and 
therewith  its  power  of  swinmiing,  whilst 
it  retains  the  remarkable  peristaltic  move- 
ments in  its  internal  substance. 

D.  viriclis.  —  Smaller  than  either  of 
the  other  species;  proteus-like  some- 
times greatly  distended,  at  others  con- 
stricted ;  filled  with  gi'een  granules ;  eye- 
specks  distinct.  Length  not  exceeding 
1-570".  D. viridis is,inPerty's  opinion, an 
incomplete  condition  of  Eutrei)tia  viridis. 

D.  planaria. — Small,  linear;  proteus- 
like,  but  capable  of  less  distension  or 
constriction  than  the  preceding ;  pointed 
at  both  exti-emities ;  colourless;  eye- 
specks  distinct.  Found  by  Ehrenberg 
amongst  Confervaa  in  the  Nile.     1-240". 


Genus  PEEANEMA  (Duj.)  (XXYI.  13).— Body  of  variable  form,  some- 
times almost  globular,  at  others  distended  posteriorly,  and  drawn  out  in  front, 
or  prolonged  into  a  long  tapering  filament.  Movement  forwards  slow  and 
uniform.  The  Peranemce  are  colomdess,  but  contain  in  theii'  diaphanous 
substance  granules  and  vacuoles.  The  lobes  they  send  out  in  their  frequent 
and  remarkable  changes  of  form  are,  unlike  those  of  the  Amcehce,  covered 
with  an  integument.  Found  in  stagnant  marsh- water,  chiefly  on  the  surface 
of  dead  plants.  I  suspect  Ehrenberg  has  described  a  species  (P.  lyrotracta) 
of  this  genus  under  the  name  of  Traclielius  trichopJiorus. 


Pebanema  protracta. — Oblong,  soft, 
dilated  posteriorly,  much  extended  an- 
teriorly. 1-838"  "^to  1-370".  Its  figure 
undergoes  changes  by  the  movements  of 
its  contents.  A  trace  of  a  red  stigma 
often  discoverable. 

V.  glohdosa  (xxvi.  1.3). — White  or 
pale-green,  nearly  globular,  more  or  less 
extended  anteriorly,  with  oblique  plaits 
on  its  surface.     In   the  Seine,    and   in 


ponds  at  Bern.  1-1625"  to  1-1300".  Perty 
could  not  discover  the  plaits  or  folds, 
and  states  that  the  filament  is  double 
the  length  of  the  body.  Movements 
ver}'  active. 

P.  virescens. — The  animalcule  so  named 
occurred  in  the  water  of  the  Seine,  was 
green,  semi-fluid,  and  changed  fonn  most 
rapidly,  like  stnAmaba.  1-860"  to  1-520". 
Requires  further  examination. 


Genus  ZYGOSELMIS  (Duj.)  (XXYI.  12  a,  6).--Animal  of  variable  form, 
swimming  by  means  of  two  equal  flageUiform  filaments,  which  are  constantly 
in  agitation.  Zggoselmis,  says  Dujardin,  is  distinguished  from  Diselmis  by 
its  contractility  and  its  variabihty  of  form ;  but  such  a  distinction  is  siu'ely 
insufficient. 


Zygoselmis  nehulosa  (xxvi.  12  a,  b). — 
Colourless,  sometimes  globidar,  at  others 
top-  or  pear-shaped,  vnth  nmnerous  con- 
tamed  granules.  1-1300",  with  two  fila- 
ments of  equal  size  and  length.  Un- 
common; found  with  Lemna;  the  changes 
of  form  proceed  slowly. 

Z.  in(equalis  (Perty)!! — Colomless,  hya- 
hne;  one  filament  rather  stouter  than 


the  other ;  both  protruded  in  front.  Ca- 
\\tj  sometimes  filled  with  clear  green 
corpuscles,  which  frequently  assume  op- 
tically a  red  hue.  Changes  of  figure 
slow  ;  movements  sluggish.  Distin- 
guished from  Z.  nebulosa  by  the  inequa- 
lity of  its  filaments.  1-840".  The  assigned 
distinction  between  this  and  the  other 
species  appears  to  us  insufficient. 


Genus  HETEROXEMA(Duj.)  (XXYI.  11).— Body  of  variable  form,  oblong, 
irregularly  dilated  posteriorly,  having  a  fine  flageUiform  filament,  and  a  second 

2n 


54G  SYSTEMATIC  HISTORY  OF  THE  INFrSORIA. 

thicker  trailing  one  acting  as  a  retractor.  This  genus,  by  possessing  the  two 
filaments  of  different  characters  and  office,  approaches  the  Heteromita  and 
Anisonema,  from  which,  however,  it  is  distinguished  by  its  contractile,  ob- 
liquely striated  integimient. 

Heteronema  marina  (xxvi.  11). —  I  narrower  in  front,  obliquely  and  closely 
Body  oblong,  irregidarly  dilated  behind,  |  striated.   Length  1-434".     In  sea-water. 

Genus  POLYSELMIS  (Duj.)  (XXVI.  7).— Animal  oblong,  of  vaiiable  form, 
swimming  by  means  of  several  flagellifonn  filaments  which  aiise  from  its 
anterior  extremity.  The  single  Infusorium  I  have  found  possessing  these 
characters  resembled  an  oblong  Euglena  rounded  at  each  end,  with  an  anterior 
longer  moveable  filament,  surroimded  by  three  or  four  very  fine  shorter  ones, 

PoLYSELMis  t7nV7/s  (xx\T[.  7). — Elon-  with  a  red  eye-speck.  1-650".  Found  in 
gated,  rounded  at  each  end ;  more  or  less  a  glass  of  marsh-water  containing  Lemna, 
dilated  and  folded  in  the  middle ;  green,     which  had  been  kept  several  months. 

Genus  EUTPEPTIA  (Perty)  (XYIII.  53-55).— Like  CUorogonium,  Zygo- 
sehnis,  and  Dinema,  has  two  filaments.  It  has  besides  the  form  of  an  Astasia, 
but  its  figure  is  constantly  varying  as  it  swims,  and  it  has  a  red  stigma. 

This  and  the  following  genus  constructed  by  Perty  are  very  imperfectly 
characterized,  and  in  oiu-  opinion  have  slight  claim  to  generic  independence. 

EuTREPTiA  viridis  (xviii.  53-65 ;  xix.  a  crawling  movement,  and  not  the  power 
18-19). — Green,  with  hyaline  corpuscles,  of  swimming.  Length,  when  extended, 
but  sometimes  quite  colourless.  A  va-  1-240".  Among  Lemnae.  A  variety,  E. 
rietj"  thick  and  rounded  posterior,  with  iinijilis,  has  only  a  single  flabellimi  and  a 
the  outline  oi  Amhiyophis,  only  presented    faintly  marked  stigma. 

Genus  DINEMA  (Perty)  (XIX.  17). — Filaments  two;  one  projected  in 
advance,  the  other  trailed  behind.  Body  small,  saccular,  very  contractile,  and 
destitute  of  chlorophyll. 


Dinema  griseolnm  (xix.  17).  —  Body 
filled  with  grey  molecules.  Movements 
sluggish,  and  pai-ticidarly  so  the  rotation 
on  its  long  axis.  Filaments  about  equal  in 


dimensions.  1-250".  Bern.  In  ponds,  &c. 
D.  jmsilhmi. — Colourless,  with  few  in- 
ternal granules.     Very  contractile,  and 
changeable  in  figure. 


FAMILY  DIXOBRYINA. 

(XXII.  42,  48,  49.) 

The  animalcules  of  this  family  are  distinctly,  or  to  all  appearance,  poly- 
gastric,  and  furnished  with  only  one  aperture  to  the  body  ;  hence,  Uke 
polj^es,  they  can  have  no  true  alimentary  canal.  They  are  possessed  of  an 
external  case  or  sheath,  and  have  the  power  at  will  of  changing  their  form, 
but  are  without  appendages,  except  one  species  of  Dinohryon,  which  has  a 
simple  filiform  proboscis  and  a  dehcate  red  spot  at  the  anterior  portion  of  the 
body.  The  nutritive  apparatus  is  obscure  and  undefined.  The  lorica  is  of  the 
form  of  a  little  pitcher  (urceolus),  to  the  bottom  of  which  the  very  contractile 
Euglena-like  creature  is  attached.     Two  genera  only  are  known. 

Genus  EPIPYXIS  (XXII.  42).— The  characteristics  of  this  genus  are 
mostly  of  the  negative  kind ;  it  wants  the  eye,  and  is  attached.  The  most 
evident  animal  character  possessed  by  the  species  is  the  funnel-shaped  orifice 
at  its  anterior  extremity.  The  soft  or  pulpy  body  is  lodged  within  a  deHcate 
membranous  (not  sihcious)  lorica,  usually  affixed  by  a  pedicle  or  foot. 

Stein  presumes  Epipyxis  to  be  merely  a  younger  condition  of  Dinohryon, 
with  which  it  occurs  frequently  in  company.  Besides  this,  the  peculiar  cell- 
like nucleus  occurs  alike  in  Epipyccis  and  in  Din.  Seriularia. 


OF  THE  PKOTOZOA. 


547 


Epipyxis  Utriculus  (xxii.  42). — Small, 
conical,  and  pitcher-like,  filled  wdth  yel- 
lowish granules ;  attached  by  a  pedicle. 


The  figure  represents  a  gToup  of  several 
attached  to  a  portion  of  Conferva. 
1-640". 


Genus  DINOBRYOIS'  (XXII.  48-49).— Distinguished  from  the  preceding 
genus  by  possessing  an  eye-speck  and  freedom  of  motion.  The  lorica  also  is 
larger  and  looser  around  the  body  of  the  creature.  Reproduction  takes  place 
by  gemmae,  which  do  not  separate  from  the  parent ;  hence  a  shmbby,  forked, 
and  polype-like  cluster  is  produced. 


DiNOBRYON  Sertularia  (xxn.  48,  49). 
— Lorica  (sheath)  large,  slightly  excised 
and  dilated  at  the  mouth,  but  constricted 
above  the  base  or  the  attached  extremity. 
This  animalcule  is  readily  overlooked,  l3y 
reason  of  its  crystalline  lorica,  and  often 
nearly  colourless  body ;  by  a  patient  in- 
vestigation, however,  the  little  colony 
may  be  perceived  rolling  along,  and  ad- 
vancing in  the  field  of  view.  Within 
each  lorica  a  pale-yeUow  animalcule  may 
be  noticed,  in  foi-m  somewhat  resembling 
the  young  of  CJilorogotiimn  or  of  Euc/lena 
viridis.  The  creature  is  able  to  contract 
itself  into  a  rounded  mass  at  the  bottom 
of  its  case,  or  it  extends  itself  to  the 
mouth  of  the  lorica,  but  not  beyond  it. 
A  red  speck  occurs  at  the  anterior  part 
of  the  body,  fi'om  which  a  single  thread- 
like filament  is  protruded  beyond  the 
sheath.  The  vibrating  filaments  of  the 
several  members  of  the  colony  propel  it 
through  the  water  like  so  many  pacldles. 
In   bog-water.     Length   of   animalcule 


1-570",  cluster  1-120".  Stein  in  the 
course  of  his  researches  met  with  a  spe- 
cimen of  Dinohnjon  Sertularia  which  he 
likens  to  a  Eugleniform  being,  living  m 
a  crystalline  goblet-like  sheath,  much 
like  that  of  Vaginicola  crystallina  or  of 
Cothiirnia  imherhis.  The  sheaths  grouped 
on  a  stem  are  only  mechanically  united 
together,  and  are  under  no  circumstances 
developed  by  progressive  gemmation  from 
the  hindmost  one,  asEhrenberg  supposed. 
Each  being  has  a  clear,  homogeneous, 
discoid  nucleus  near  its  base,  containing  a 
central  nucleolus. 

D.  (P)  soeiale. — Small,  enveloped  in  a 
shell  of  a  simply  conical  shape,  truncated 
at  the  mouth.  Developed  in  the  fomi  of 
a  shrub-like  poh-parv.  In  fresh  water. 
1-860",  cluster  1-280". 

D.  gracile.  —  Less  branching  (fruti- 
cose),  lorica  slightly  constricted  at  the 
middle,  aperture  truncated.  Animalcule 
1-2080". 


OF  THE  GROUP  PROTOZOA  (p.  199). 

In  the  an-angement  pui'sued  in  the  first  part  of  this  work  the  Protozoa  follow 
the  Phytozoa,  and  are  primarily  di\-ided  into  two  chief  subsections,  viz. — 
Rhizopoda  and  CiHata.  These  we  shaU  treat  as  two  groups  of  Infusoria, 
divisible  into  a  few  subgroups,  and,  commencing  with  the  Rhizopoda,  shall 
treat  systematically,  fii'st  those  beings  properly  called  so,  and  afterwards,  as 
subgroups,  the  Actinophrj^na  and  the  Acinetina.  The  Ciliata  and  their  divi- 
sions will  follow  next. 


GROUP  TI.— RHIZOPODA  (p.  201). 

(Plates  XXI.-XXIII.) 

This  term  and  its  synonym  Pseudopoda  are  derived  from  the  leading  charac- 
teristic of  the  class,  viz.  the  variable  processes  or  false  feet  which  serve  as  their 
locomotive  organs.     The  former  appellation  is  more  in  vogue,  but  its  extent 

2^2 


548  STSTEilATIC  HISTORY  OF  THE  INFrSORTA. 

of  signification  is  ill-defined.  Some  would  apply  it  to  the  whole  collection  of 
animalcules  composed,  as  far  as  their  organic  material  is  concerned,  of  the 
self- same  simple  homogeneous  sarcode,  whether  this  exist  naked,  as  in  the 
Amoebaea,  or  whether  enclosed  within  a  simple  single-chambered  shell,  as  in 
the  Monothalamia,  or  in  a  many-chambered  or  compound  one,  as  in  the  Poly- 
thalamia  or  Foraminifera.  Siebold  extends  to  the  Rhizopoda,  as  a  class,  this 
wide  signification.  Others,  and  among  them  Ehrenberg,  would  so  far  limit 
it  as  to  assign  to  it  only  the  naked  Amoebaea  and  the  monolocular  Arcellina. 
Indeed,  the  last-named  author  holds  the  opinion  of  an  actual  difi'erence  in 
organic  nature  between  his  presumed  Polygastric  Pseudopoda  and  the  Fora- 
minifera or  Polysomatia.  Dujardin  adopted  the  peculiar  coiu'se  of  rejecting 
the  Amceba^a  from  the  Ehizopoda,  which  in  his  system,  included  both  mono- 
locular and  multilocular  forms.  In  our  general  history  of  the  Ehizopoda 
(p.  201),  we  have  used  the  term  in  its  widest  signification,  to  include  naked 
monolocular  and  multilocular  beings ;  but,  in  order  to  keep  this  systematic 
portion  of  our  work  within  moderate  bounds,  we  shall  here  give  only  the 
descriptive  accoimt  of  the  Amoebaea  and  ArceUina.  Were  another  reason 
required  than  that  assigned  for  this  proceeding,  a  strong  one  might  be  found 
in  the  fact  of  the  approaching  completion  of  an  elaboi^ate  work  on  the  Pora- 
minifera  by  Professors  Williamson  and  Carpenter,  who  are  so  well  kno^Ti  for 
their  extensive  acquaintance  with  this  class  of  organisms. 

Families: — I.  Amoebaea  ;  2.  Monothalamia  (Arcellina);  3.  Polytha- 
lamia  (Foraminifera);  4.  Actinophryina ;  5.  Acinetina. 

FAMILY  I.— AMCEBJEA  on  AMCEBINA. 

The  Amcebaea  present  the  simplest  form  of  organic  life,  and  are  typically 
represented  by  a  microscopic  particle  of  '  sarcode,'  or  muco-gelatinous  organic 
matter,  possessing  within  itself  the  power  of  growth,  of  assimilation  of  ex- 
traneous substances,  of  movement  by  means  of  irregular  and  ever-changing 
offshoots  from  itself — "  variable  processes," — and  capable  of  multii^lication  by 
the  severance  of  portions  of  itself,  and  probably  of  development  by  internal 
germs  or  gemmules.  They  present  no  definite,  constant  figiu-e,  although  it  is 
possible  to  distinguish  different  Amoebaea  by  the  more  frequent  outline  they 
exhibit,  or  by  the  length  or  figm^e  of  theii'  pseudopodes.  The  general  opinion 
is  that  the  sarcode  of  which  they  consist  is  naked  and  homogeneous ;  but 
Auerbach  (see  ante,  p.  205)  has  advanced  the  statement  that  they  are  all  en- 
closed ^TLthin  an  integument.  A  movement  of  granules  is  perceptible,  espe- 
cially along  the  margins  of  the  variable  processes.  A  nucleus  with  a  nucleolus  is 
believed  to  be  generally  present ;  vacuoles  are  almost  always  distinguishable ; 
and  one,  two,  or  even  more  contractile  vesicles  have  been  seen  in  some  speci- 
mens. There  seems  evidence  of  the  process  of  encysting  taking  place  under 
certain  conditions.  Amoebiform  beings  are  not  necessarily  of  an  animal  nature ; 
for  some  have  latterly  been  proved  to  occur  in  the  cycle  of  development  of  some 
of  the  simplest  plants.  Ehrenberg  described  Amoebaea  as  polygastric  ani- 
malcules, ha^dng  a  mouth  but  no  alimentary  canal,  and  mo"sdng  by  variable 
processes,  produced  from  any  part  of  the  body  indiff'erently.  He  observed 
vacuoles  (digestive  sacs)  in  all,  and  sclf-di\ision  in  Amoeba  diffluens.  The 
Amoebaea  are  organically  related  to  the  Arcellina  and  Foraminifera,  from 
both  of  which  groups  they  differ  by  being  naked,  or  unenclosed  in  a  shell 
(see  p.  234). 

Only  one  genus  is  distinguishable,  viz. 

Genus  AMCEBA,  which  is  therefore  represented  by  the  description  of  the 


OF  THE  AM(EBJiA  OR  A]H(EBINA. 


549 


family.   The  following  species,  however,  are  distinguished,  although  it  is  hard 
to  define  specific  form  in  such  variable  creatures, 
Amceba  Pnnceps  (xxi.  4).  —  Colom- 


pale  yellow,  processes  numerous,  of  a 
cylindrical  outline,  with  thick,  rounded 
extremities.  Its  figure  when  in  a  passive 
or  non-reptant  condition  is  globidar ;  but 
this  character  is  of  no  specific  value,  the 
natural  tendency  of  any  similar  semi- 
fluid, mucous  particle  being,  by  the 
force  of  cohesion,  to  assume  such  a  form. 
Amongst  NavmdcB  and  Algae  in  fresh 
water.     1-140"  to  1-70", 

A.  rerrucom. — Smaller  than  the  last ; 
colomless ;  processes  globular,  ovoid,  of 
a  wart-like  appearance.  Motion  sluggish, 
like,  indeed,  all  Amcehce.  Never  exceeds 
1-240".     Amongst  aquatic  plants. 

A.  diffluens. — Colomless  j  expands  into 
a  filmy  form  and  throws  out  processes 
which  are  longer  than  those  of  A.  verru- 
cosa, and  rather  pointed  at  the  ends. 
This  species  is  a  very  interesting  object 
under  the  microscope :  at  times  it  re- 
sembles a  tm'bid  lump  of  jelly-looking 
matter,  at  others  a  transparent  gelati- 
nous film,  with  numerous  outstretched 
processes  slowly  protruded  at  one  part 
and  withdrawn  into  the  general  mass  at 
another,  but  so  acted  on  as  to  serve  to 
produce  a  very  slow  onward  movement. 
Its  movements  may  be  compared  in  ap- 
peai-ance  to  those  which  may  be  imagined 
as  exhibited  by  a  many-footed  animal 
tied  up  in  a  sack.  Usual  size  1-300". 
Common  amongst  Lenmae. 

A.  radiosa  (xxii.  1-3). — Colourless; 
smaller  than  A.  diffluens ;  processes  nu- 
merous, long,  slender,  pointed,  disposed  in 
a  radiating  manner.  When  contracted,  it 
resembles  A.  diffluens  in  its  globose  figure. 
Colouring  matter  is  readily  taken  into 
its  substance.     In  bog-water.    1-240". 

A.  longipes.  — Very  small ;  processes 
very  long,  one  of  them  often  fom-  times 
the  length  of  the  body ;  acute  and  hya- 
line, without  expansions.  1-2500".  Ciix- 
haven,  in  the  sea. 

A.  Roeselii  (Duj.). — Diaphanous;  pro- 
cesses numerous,  some  very  obtuse,  others 
digitate,  and  others  also  pointed  or 
jagged.  1-1.30".  Large  vacuoles  occur 
about  the  middle  of  the  body,  looking 
like  large  globules. 

A.  marina  (D.). — Filled  with  granules 
at  the  centre  ;  differs  fi-om  A.  diffluens 
only  in  its  dimensions  and  habitat,  i.  e. 
the  sea.     1-260". 

A.  Gleichenii  (D.). — ^\''aries  from  a  glo- 
bular to  a  veiy  long-oval  figm-e ;  dividing 
into  two  or  three  lobes   on   one  side; 


vacuoles,  and  some  nearly  opaque  gra- 
nular bodies,  at  the  centre.  1-400'^  to 
1-300". 

A.  multiloba  (D.). — This  may  be  but  a 
[  variety  of  A.  Gleichenii,  but  deserves 
pointing  out,  as  much  from  the  circum-' 
stance  of  its  habitat  as  from  its  form. 
1-1300".  It  seems  softer  than  other 
species,  and  moves  actively,  emitting 
from  its  border  in  various  directions  ten 
or  twelve  rounded  lobes,  which  give  it  a 
most  irregidar  figure.  It  was  foimd  in 
an  infusion  of  meal  which  had  been  kept 
nearly  two  months. 

A.  Limax  (D.)  (xxn.  4-6). — Diapha- 
nous, roimded  on  each  side,  more  or  less 
globose,  and  but  slightly  lobed;  glides 
along  in  a  nearly  straight  line  ;  contains 
very  distinct  granides,  and  a  very  clearly 
marked  vacuole.  Found  in  Seine  water 
kept  for  eight  months.  It  may  be  but  a 
more  advanced  degree  of  development 
of  the  preceding,  or  of  the  following 
species;  its  greater  transparency,  how- 
ever, and  its  semi-fluid  consistence,  seem 
sufliciently  distinctive.  1-260"  to  1-800". 
Auerbach  suggests  that  this  species  is 
only  a  young  form  of  A.  Princeps. 

A.  Guttula  (xxii.  6).  —  Diaphanous, 
orbicular  or  ovoid ;  glides  in  a  straight 
course,  and  contains  very  distinct  gra- 
nules. This  is  one  of  the  most  common 
species,  but  may  easily  escape  notice  on 
account  of  its  great  transparency,  the 
simplicity  of  its  form,  and  the  slowness 
of  its  movements.  In  river-  or  marsh- 
water,  kept  for  some  time_,  containing 
plants.     1-520"  to  1-890". 

A.  lacerata  (D.). — Symmeti-ical,  ru- 
gose, plaited,  and  gTanular,  rather  dia- 
phanous, with  broad  expansions,  looking 
membranous  at  the  base,  temiinated  by 
several  tapering  torn  points ;  one  or  more 
evident  vacuoles.  1-2800"  to  1-890".  In 
pond-water. 

A.  hrachiata  (D.).  —  Globidar;  semi- 
transparent,  porous  and  tubercidar,  with 
four  to  six  very  thin  long  and  cylin- 
drical expansions,  straight  or  flexuose, 
sometimes  bifid  or  branching.  In  animal 
infusions.     1-190". 

A.  crassa  (D.). — More  or  less  rounded, 
thick ;  contains  nimierous  granides ;  ex- 
pansions rounded,  numerous,  not  very 
prominent.  1-880"  to  1-520".  In  the 
water  of  the  Mediten-anean. 

A.  rajnosa  (D.). — Globular  or  ovoid; 
granides  veiy  numerous ;  expansions  nu- 
merous, of  nearly  equal  size,  roimded  at 


550 


SYSTEMATIC  HISTOKT  OF  THE  IMFUSORIA. 


the  extremities,  of  the  same  length  as 
the  body,  and  mostly  branched. 

Other  varieties  of  these  pecidiar  beings 
are  referred  to,  but  not  specially  described, 
by  Dujardin ;  for  one,  however,  he  pro- 
poses the  name  of  Amceha  injiata. 

A.  quadrUineata  (Carter).  —  1-350". 
Mr.  Carter  has  given  this  name  to  a 
supposed  new  species  (A.  N.  H.,  1856, 
xviii.  pp.  243,  248),  of  which  he  gives  a 
diagi'am,  but  no  specific  description. 

A.  lateritia  (Fresenius). — Bounded  or 
oval,  or  drawn  out  at  one  end  and  rounded 
at  the  other.  Processes  thin,  linely 
pointed ;  points  very  numerous  •  colour 
of  a  brick-red,  becoming  brow^ner  after 
death.  In  water  at  Walldorf  with  >S)^i- 
rotcenia.     1-20  to  1-10  millim. 

A.  actinophora  (Auerbach)  (xxii.  12- 
18). — When  without  processes,  its  form 
is  more  or  less  globular ;  and  even  when 
pseudopodes  are  protruded,  the  figure  is 
usually  not  much  altered,  those  pro- 
cesses being  thin  and  spicular  with 
pointed  ends  (fig.  13),  though  they  do 
not  exceed  in  length  more  than  1^-  the 
diameter  of  the  body.  This  species  is 
remarkable  for  the  number  of  crystalline 
particles  found  in  its  interior,  and  for 
the  processes  never  being  entered  by  the 
granules  of  the  interior  of  the  JDody. 
Auerbach  believes  that  the  Actino- 
phnjs  viridis  of  Ehrenberg  is  probably 
no  other  than  a  large  specimen  of  this 
Amoeba.  It  is  closely  allied  to  A.  hilim- 
hosa,  but  is  smaller,  its  surface  smooth, 
its  processes  radiating  and  simple,  not 
forked,  its  envelope  thinner :  it  contains 
the  peculiar  crystals,  and  has  no  starch- 
globules  as  seen  in  the  latter.  1-110'"  to 
1-70"'.    In  water  at  Breslau. 


A.  hilimhosa  (Auerbach)  (xxn.  7-11, 
20-23). — Figure  more  or  less  globular 
when  processes  absent  or  few ;  pseudo- 
podes vary,  being  either  wdde  and  laminar 
with  a  spinous  or  dentate  terminal  mar- 
gin, or  elongated  and  tubular.  1-50'"  to 
1-35"'. 

A.  porrecta  (Schultze)  (xxi.  3). — Hy- 
aline ;  processes  numerous  from  all  sides 
of  the  irregularly-shaped  mass,  from 
eiglit  to  ten  times  longer  than  the  latter, 
divergent  like  so  many  fibres,  with  in- 
tercommunicating branches.  Fissure 
very  changeable  and  rapidly  so ;  remark- 
ably locomotive.  The  tine  granules  seen 
to  circidate  through  the  processes.  In 
fresh  and  salt  water. 

A.  (/lohidaris  (Schultze)  (xxi.  2). — 
Granular,  delicate,  yellowish-brown, 
central  portion  surrounded  by  a  hyaline 
cortical  lamina,  from  which  the  short, 
stumpy  processes  are  very  slowly  pro- 
truded and  withdra\Mi.  Most  of  the 
processes  are  also  remarkable  from  their 
rounded  truncate  ends  being  terminated 
by  a  retractile  spine.     Ancona. 

A,  polypodia  (Schultze).  —  Processes 
numerous,  long,  slender,  wdth  rounded 
or  truncate  extremities,  and  hyaline ; 
movements  tolerably  active.  Lagoon- 
water,  Venice. 

A.  Schidtzii  (xxi.  1). — A  species  indi- 
cated but  not  named  by  Schultze ;  to 
distinguish  it,  w^e  have  applied  to  it 
that  eminent  naturalist's  name.  Central 
portion  granular ;  surrounding  lamina 
hyaline;  no  granules  enter  the  interior. 
Processes  short,  tubercular,  with  rounded 
extremities.  Possibly  the  same  as  A. 
verrucosa  (Ehr.),  In  long-kept  water 
from  Ancona. 


Supplementarif  Genera,  or  Subfamily  of  AMGEBIIS'A. 

Geniis  COEYCIA  (Diij.). — An  Amoebiform  being,  covered  by  a  very  expan- 
sible, elastic,  flexible  membrane  or  sac,  which  becomes  folded  in  different 
dii'cctions  by  the  movements  and  contractions  or  expansions  of  the  animalcule, 
— the  whole  organism  sometimes,  after  it  has  several  times  tiuTied  on  itself, 
looking  like  a  folded  piece  of  linen.  The  membrane  remains  distinct  after  the 
animalcule  is  torn  by  needles,  and  the  sarcode  particles  evacuated.  The  latter 
contract  themselves  into  little  balls,  and,  by  the  property  of  vacuolation,  become 
hoUowed  by  little  cavities  in  larger  or  smaller  numbers.  The  contents  con- 
sist, besides  sarcode,  of  granules,  vacuoles,  and  foreign  pai-ticles ;  the  first- 
named  move  in  currents  from  one  part  to  another.  The  expansions  are  not 
pushed  forward,  nor  do  they  glide  along  the  surface  of  reptation  like  those  of 
ArceUina  or  of  naked  AmoehcB ;  they  proceed  from  various  points  of  the  general 
mass  or  body,  and  seem  to  seiwe  rather  to  change  the  centre  of  gravity  than 
to  furnish  a  point  d^appui.     8-100'"  to  20-100'". 

The  name  is  suggested  by  the  membranous  envelope,  which  preserves  the 


OF  THE  ARCELLINA.  551 

animalcules  from  beiug  diied  up  during  the  alternations  of  diyness  mth 
moisture  they  are  exposed  to  by  their  habitat  in  mosses.  They  are  procured 
by  lightly  pressing  the  Jungennanniae,  moistened  by  the  rains  of  November 
or  December,  or  after  they  have  been  j^reserved  a  little  time  in  water. 

This,  as  Dujardin  remarks,  is  evidently  a  new  genus,  intermediate  be- 
tween the  naked  and  the  loricated  Ehizopoda,  and  standing  in  a  certain 
relation  with  the  NoctUucce.     {A.  S.  N.,  1852,  vol.  xviii.  p.  240.) 

No  species  named. 

Genus  PAMPHAGUS  (Bailey). — An  Amoebifoi-m  being,  covered  by  a  deli- 
cate elastic  integument,  which,  although  it  presents  astonishing  changes  of 
form,  and  offers  a  certain  amount  of  resistance  to  internal  and  external  pres- 
sui'e,  yet  admits  of  the  animalcule  transfixing  itself  upon  any  denser  thin 
portion  of  matter  without  any  apparent  damage  (p.  220). 

They  connect,  says  their  discoverer,  "  the  genus  Amceba  with  Difftugia, 
agreeing  with  the  first  in  the  soft  body  without  shell,  but  differing  in  having 
tme  feelers  or  rhizopods  confined  to  the  anterior  part  of  the  body,"  or  to  the 
region  of  the  mouth,  as  in  Diffiugia.  A  specimen  of  PampliaguSy  we  may 
remark,  is  equivalent  to  a  Difftugia  "^dthout  a  true  shell  and  with  no  ex- 
traneous matters  to  thicken  and  strengthen  its  covering.  Dr.  Bailey  met 
with  these  animalcules  in  a  vivarium,  into  which  "  bits  of  boiled  beans  and 
potatoes  had  occasionally  been  introduced  as  food  for  other  animalcules," 
and  numerous  starch  granules  were  found  in  their  interior.  He  also  repre- 
sents it  as  having  a  mouth,  and,  being  an  adherent  of  Ehrenberg,  as  polygas- 
tric ;  but  the  mouth  so  described  was  the  orifice  of  the  sac  through  which 
the  pseudopodes  were  protruded,  and  therefore  the  homologue  of  the  foramen 
of  monothalamous  shells. 

This  genus  is  evidently  very  closely  allied  to  Corycia  (Duj.).  The  only 
difference  of  moment  is  that  in  the  latter  the  expansions  of  the  sac  proceed 
fi'om  any  part  of  the  surface,  whilst  in  Pampliagus  its  discoverer  describes 
them  as  given  off  only  from  one  spot  at  the  anterior  end. 

FAMILY  II.— ARCELLINA  (Ehr.)    (Pt.  I.  p.  201  et  seq.) 
(XXI.  6-17.) 

Amoehce  invested  with  a  single-chambered  eeU  or  lorica,  having  also  but 
one  opening,  mouth,  or  foramen.  The  animal  substance  or  sarcode  contained 
within  the  sheU  is  indistinguishable  from  that  of  the  naked  Amcehce,  and  is 
not  more  organized.  The  form  of  the  pseudopodes  given  off  from  around  the 
mouth  of  the  shell  are  to  some  extent  employed  in  defining  species ;  but  the 
size  and  confonnation  of  the  shell  and  of  its  opening  are  of  much  more  im- 
portance systematically. 

Ehrenberg  instituted  this  family  for  all  one -chambered  Phizopodous  sheUs 
which,  in  his  belief,  were  of  a  siHcious  composition,  and  rejected  from  it 
some  similar  sheUs  which  were  of  a  calcareous  character.  This  distinction, 
however,  is  based  on  erroneous  notions  (p.  219)  ;  and  naturalists  now  concur 
m  bringing  together  all  unilocular  Phizopoda  into  one  group,  under  the  name 
of  Monothalamia. 

The  Arcellina  were  represented  by  Ehrenberg  as  poly  gastric  animals, 
with^  an  ahmentary  canal,  and  enclosed  by  a  lorica,  through  the  single 
openmg  of  which  they  extended  their  variable  processes.  He  also  described 
digestive  sacs,  but  was  unable  to  discover  either  theii-  mode  of  reproduction 
or  their  multiplication  by  fission  or  gemmae. 

Only  four  genera  of  Arcellina  were  enumerated  by  Ehrenberg;  their  cha- 
racters and  mutual  relations  are  shown  in  the  following  tabular  view : — 


552  SYSTEilATIC  HISTOEY  OF  THE  INFrSORIA. 

Changeable  processes      f      Lorica  spherical  or  tun -like Difflugia, 

radiant,   generally     -1      Lorica  a  flat  spiral    Spirilliua. 

numerous    [      Lorica  discoid  or  shield-shaped  Aj-cella. 

Changeable  processes  broad  and  unbranched    Cyphidium. 

The  genus  SpirlUina  is  a  veiy  exceptional  form ;  it  has  a  spii^ally-coiled 
shell,  apparently  porous  throughout,  Kke  one  of  the  Foraminifera,  and  like 
them,  too,  a  marine  habitat.  Its  only  affinity  with  the  Ai'cellina,  according 
to  Ehrenberg's  account,  is  the  silicious  nature  of  the  shell ;  but  even  were 
this  established,  it  would  not  exclude  it  from  the  Foraminifera,  among  which 
silicious  testae  are  kno^vn.  Of  Ci/phidium  little  information  exists ;  and 
Ehrenberg's  account  is  by  no  means  satisfactory.  The  same  may  be  said  of 
the  figures  he  gives  of  it. 

Dujardin  divides  the  '*  Ehizopodes,"  excluding  the  Amoebaea,  into  two  sec- 
tions, according  to  the  form  of  the  variable  expansions.  The  first  section  cor- 
responds to  the  family  Arcellina  of  Ehrenberg,  and  comprehends  those  species 
provided  with  short  thick  expansions,  rounded  at  the  extremity.  Such  are 
the  Diffiugice,  'possessing  a  flexible  membranous  lorica,  without  visible  tex- 
ture, mostly  of  globular  form,  from  the  aperture  of  which  the  expansions 
radiate :  such,  too,  are  the  Arcellce,  having  a  discoid  lorica,  flattened  on  the 
side  along  which  they  move  (the  plane  of  reptation),  where  is  a  central 
round  opening,  from  which  the  expansions  proceed,  the  latter  lying  thus  be- 
tween the  shell  and  the  siu-face  along  which  it  glides ;  the  lorica,  moreover, 
is  brittle,  and  often  reticulated,  or  areolated.  The  second  section,  much 
larger,  comprises  beings  of  every  variety  of  form,  and  having  very  numerous 
fllilbrm  expansions,  ending  by  very  fine  extremities.  Of  these  varieties  he 
makes  three  tribes ;  the  first  distinguished  from  the  Difflugice  only  by  the 
slender  character  of  the  expansions,  except  that  in  one  genus,  Trinema,  the 
opening  is  lateral ;  the  second,  represented  by  the  genus  Euglypha,  having  a 
lorica  beset  with  tubercles,  or  areolae,  disposed  spii-ally ;  and  the  thii^d  by  the 
genus  Gromia,  having  a  spherical  membranous  shell,  and  very  long  and 
branching  expansions. 

The  remainder  of  the  "  Ehizopodes,"  as  described  by  Dujardin,  are  com- 
prehended in  the  Polythalamia  by  other  authors.  Of  these  he  constitutes  two 
tribes, — one  represented  by  the  single  genus  Miliola,  which,  hke  Gromia  and 
the  examples  of  the  first  tribe,  has  but  a  single  large  opening  in  its 
lorica  for  the  escape  of  the  expansions ;  the  other  by  several  genera,  all 
of  which  give  off  numerous  filiform  expansions  from  many  distinct  pores 
(foramina)  of  their  shells,  and  hence  called  Foraminifera. 

Siebold  included  the  first  and  second  divisions  of  Dujar din's  class  Rhizo- 
poda  in  his  group  of  Arcellina. 

M.  Schultze  framed  the  division  of  the  Monathalamia  from  the  structure 
of  the  shells ;  but  he  admitted  amongst  them  the  genus  Orhulina,  which 
possesses  the  very  exceptional  character  of  having  numerous  pores  to  its 
shell,  instead  of  a  single  opening.  The  three  families  instituted  were: — 
1.  Lagynida;  2.  Orbulinida;  3.  Cornuspiiida  (see  p.  241).  The  first-named 
family  corresponds  most  nearly  to  Ehrenberg's  Arcellina,  although  it  con- 
tains several  genera  usually  described  in  histories  of  the  Foraminifera,  and 
omitted  by  the  Berlin  natui'alist.  The  following  are  enumerated : — Arcella, 
Difflugia,  Cypliidium,  Trinema^  Eughjpha,  Gromia,  Lagijnis,  Ovulina  (d'Or- 
bigny),  Fissurina  (Eeuss),  Squamulina,  and  the  doubtful  genera  of  Schluni- 
berger — Lecquereusia,  Cyphoderia,  Pseudodijffiugia,  and  Sp)henoderia.  The 
genera  Lagynis  and  Squamidina  are  two  new  ones  formed  by  Schultze  him- 
self.    It  will  make  this  history  more  complete  to  introduce  these  new  genera 


OF  THE  AECELLINA. 


553 


of  Lagynida,  as  well  as  the  interesting  Cornus^pira  described  by  Scliultze.    Of 
Fissurina  we  have  no  details. 

Dr.  Bailey,  of  New  York,  adds  another  new  genus  to  the  Monothalamia, 
under  the  name  of  Caclium. 

Genus  DIFFLUGIA. — Shell  of  one  chamber  (unilocular)  with  a  single 
aperture,  usually  of  a  more  or  less  spherical  or  ovoid  shape,  but  sometimes 
more  elongated  and  clavate,  or  pitcher-shaped;  thin,  opaque,  of  a  dark 
olive  or  brown  colour,  in  general,  when  occupied  by  the  hving  organism,  but 
when  empty,  hyahne  and  colomiess.  The  sui-face  of  the  shell  is  either  smooth 
or  sculptured,  and  occasionally  armed  with  spine-like  processes.  In  a  few 
species,  D.  proteiformis,  D.  acuminata,  and  D.  gigantea,  the  envelope  does 
not  acquire  even  the  usual  homy  consistence,  but  is  soft,  and  becomes 
strengthened  by  the  adhesion  of  foreign  particles  of  silex  and  other  matters, 
which  give  it  a  rough,  irregular  appearance.  The  aperture  or  foramen 
varies  in  figure  and  size,  and  furnishes  valuable  specific  distinctions.  The 
pseudopodes  are  characterized  as  being  cylindrical,  not  much  elongated,  and 
obtuse  or  rounded  at  the  extremities. 


DiTTLUGiA  proteiformis. — Ovate,  sub- 
globose,  covered  by  a  coating  of  minute 
grains  of  sand,  and  either  of  a  deep  olive, 
black,  or  greenish  colour.  Processes 
hyaline,  from  1  to  10.  1-240".  Among 
Oscillatoriae. 

D.  ohlonga. — Oblong,  ovate,  or  orbi- 
cular, smooth,  and  of  a  brownish  colour ; 
processes  fewer  and  stouter  than  those 
of  the  preceding  species.  Among  Oscil- 
latoriae,  &c.  1-200".  Surface  irregu- 
larly reticulated. 

J),  acuminata. — Oblong  and  rough, 
w-ith  minute  grains  of  sand ;  posteriorly 
pouited ;  processes  hyaline.     1-70". 

D,  Enchelijs  (xxi.  19  «,/). — Oval ;  co- 
lomiess ;  translucent  and  smooth,  round- 
ed dorsallv;  processes  transparent, 
slender  and  small ;  apertiu-e  lateral.  This 
is  the  smallest  species  of  the  genus. 
1-30'"  1-15"'.  In  stagnant  water.  Du- 
jardin  refers  it  to  his  genus  Trinema. 

D.  Ampulla. — Oblong,  club-shaped,  ele- 
gantly marked  by  an  oblique  series  of 
dots  (puncta)  ;  hyaline ;  foramen  ovate. 
1-680".     At  Salzburg. 

D.  spiralis  (Bailey). — Sub-globose,  mi- 
nutely granidated :  upper  sm-face  un- 
equal, with  a  spiral  line  of  two  or  three 
tmns.  Variable  processes  niunerous, 
constantlv  changini?  position,  hvaline. 
1-680".  ^  Berlin  and  United  States. 
Fresenius  remarks  that  some  large  spe- 
cimens are  met  with  coated  \%dth  coarse 
particles,  like  D.  proteiformis,  instead 
of  the  usual  finely  reticulate  lines.  It 
attains,  he  says,  in  size  to  1-7"'. 

D.  acantliophora  (xii.  64).  —  Ovate, 
oblong,  loosely  areolated  ;  foramen  den- 
tated;  armed  posteriorly  with  three  or 
fo\u  spines  (aculei). 


D.  areolata. — Lorica  and  foramen  as 
in  the  preceding,  but  the  spines  defi- 
cient. 

D.  dentieulata. — Ovate,  oblong,  smooth ; 
foramen  with  twelve  dentations. 

D.  Lagena. — Clavate,  or  oftheformof 
a  bottle ;  smooth,  without  reticulations ; 
margin  of  opening  entire. 

D.  Icevigata. — Ovate,  oblong,  smooth ; 
foramen  with  eight  dentations ;  ap- 
proaches D.  dentieulata. 

1).  striolata. — Ovate,  oblong,  delicately 
striated  longitudinally  j  foramen  with  a 
dentated  border. 

D.  Bructeri. — Ovate,  surface  rugose  ; 
the  end  presenting  the  aperture  rather 
attenuate  but  tmneate ;  margin  of  aper- 
ture entire.     1-1050".     On  moss. 

D.  cancellata. — Oblong,  obtuse ;  sur- 
face beset  with  imperfectly  rounded  cells, 
5  to  6  in  1-2500" ;  aperture  narrow,  en- 
tire.    1-1040".     On  moss. 

D.  ciliata.  —  Ovate,  surface  areolar  ; 
each  posterior  areola  furnished  with  a 
cilium  or  cirrhus ;  constricted  towards 
the  foramen,  which  has  10  to  16  denti- 
culations.  1-936''.  Conmiou  in  Her- 
cynia. 

D.  seinimdum. — Shorter,  ovate,  brown, 
surface  with  narrow  and  small  areolae ; 
aperture  wide,  verv'  finely  denticidated 
or  entire.  1-2500"  "to  1-1250".  On  moss 
and  stones. 

D.  collaris. — Narrowed  like  a  neck  be- 
hind the  aperture ;  straight,  attenuate, 
pyriform  or  sub-clavate  ;  surface  irregu- 
larly ceUular;  cells  small,  but  of  equal 
size,  except  about  the  neck,  where  they 
are  smaller;  apertiu-e  entire.  1-840". 
About  roots  of  trees. 


554 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


D.  Dryas.  —  Ovate  ;  aperture  entire, 
truncate ;  surface  marked  wdtli  longitu- 
dinal lines  of  ovate  cells,  which  decrease 
in  size  posteriorly.  1-1170".  On  roots 
of  trees. 

D.  oligodon.  —  Smooth,  oblong,  sub- 
cylindrical;  aperture  with  eight  strong 
denticulations.  1-1000".  This  spacies 
and  the  two  following  found  in  Kur- 
distan. 

D.  reticulata. — Ovate,  surface  marked 
by  a  net- work  of  minute  cells ;  aperture 
simple,  large.  In  its  interior  are  nu- 
merous particles  like  aggregated  buds; 
the  margin  of  the  foramen  is  sometimes 
dentate.     1-880". 

D.  squamata. — Ovate,  with  large  loose 
areolae,  looking  like  scales  (squamse) ; 
aperture  denticulate,  truncate,  contracted. 
1-1450". 

D.  spirt ff era. — Pyriform,  smooth ;  neck 
distinct,  cylindrical,  truncate;  orifice 
large,  entire ;  opposite  end  turgid ;  round- 
ed. The  surface  presents  four  spiral  lon- 
gitudinal lines.    1-36"'.    Bavarian  Alps, 

The  first  of  the  appended  species  is 
from  Dujardin,  the  others  from  Schlum- 
berger  (Ami.  des  Sciences  Nat.  1845, 
p.  254)  :— 

D,  glohidosa  (xxi.  10). — Brown,  glo- 
bular, or  ovoid,  smooth.  1-260"  to 
1-105".     Near  Paris. 

D.  depressa. — Diaphanous,  ovoid,  de- 
pressed, resistant ;  its  surface  divided  by 


slight  fissiu'es  (lines)  into  numerous 
small  and  irregular  polygonal  sections. 
1-220".  Aperture  with  an  uneven  mar- 
gin.    In  springs  in  the  Vosges. 

D.  gifjcvntea. — Greyish  brown,  rough, 
as  if  strewed  with  particles  of  sand, 
ovoid,  elongated,  and  contracted  an- 
teriorly. 1-325"  to  3-325".  It  ap- 
proaches D.  proteiformis,  but  differs  in 
its  more  elongated  form,  in  being  con- 
tracted anteriorly  and  almost  pyriform, 
sometimes  depressed,  and  lastly  in  its 
greater  size  :  margin  of  aperture  uneven. 

D.  tricuspis  (Carter). — Processes  occu- 
pied by  granules,  greenish  ;  testa  ovoid, 
little  incrusted ;  its  foramen  tricuspid  in 
form,  or  of  trefoil  shape  {A.  N.  H.  1856, 
xviii.  p.  247).  Fresenius  appears  to  have 
met  with  this  form,  but  considers  it  only 
a  variety  of  D.  ohlonga.     1-320". 

D.  ?  marina  (Bailey), — Shell  silici- 
ous  (?),  ovoid  or  lagenoid,  with  a  con- 
tracted neck  and  circular  aperture ;  sur- 
face divided  by  oblique  lines  into  quadri- 
lateral spaces.  oV  of  1-1000",  diam.  1^  of 
1-1000". 

A  single  specimen  was  found  in  sound- 
ings taken  from  a  depth  of  2750  fathoms, 
which  had  been  cleaned  with  acids. 
This  resistance  to  acids  induced  Dr. 
Bailey  to  consider  the  shell  silicious, 
but  we  now  know  that  chitinous  shells 
are  equally  unaffected.  The  discoverer 
doubted  its  being  a  Diffiugia,  on  account 
of  its  marine  habitat. 


Genus  SPIRILLUSTA. — Lorica  tubular,  silicious  (?),  rolled  in  a  spiral 
manner,  like  a  Planorhis.  It  is  allied  to  Difflugia  by  its  silicious  lorica  (for 
acids  have  no  action  on  the  shell).  This  genus  probably  agrees  with  the 
Spirulina  of  Bory  de  St.  Vincent;  but  the  latter  name  has  been  otherwise  used 
by  Ehrenberg  to  designate  a  genus  of  Polythalamia. 


Spirillina  vivipara  (xi.  37). — Shell 

})orous,  convoluted  as  a  circular,  spiral, 
lorizontal  tube,  hyaline  and  smooth. 
Yovmg  loricpe  may  often  be  found  con- 
nected with  it.  In  the  sea — Vera  Cruz, 
Mexico. 

The  form  of  this  species  recalls  that 
of  many  undoubted  Polythalamia,  whilst 
it  has  no  fellow  amongst  the  Infusoria. 
Ehrenberg  has  likewise  represented  ap- 


parent dots  or  pores  on  its  surface,  like 
those  through  w^liich  the  filifonn  pro- 
cesses of  Polythalamia  are  protruded; 
and  the  only  reason  implied  in  Eliren- 
berg's  account  for  reckoning  it  among  the 
Polygastrica  is  its  silicious  shell :  it  is, 
however,  most  probably  chitinous.  It 
will  be  noted  that  Ehrenberg  is  inclined 
to  believe  it  viviparous. 


Genus  ARCELLA  (XXI.  7-9,  15). — Variable  processes,  numerous  and 
hyaline;  single  processes  cleft  into  many,  and  expanded  in  a  radiating 
manner ;  lorica  flattened,  shield-like.  The  lorica  varies  much  in  structure  in 
the  different  species.  Eor  instance,  in  A.  vidyaris  it  exhibits  regular  and 
delicate  facets  ;  in  A.  dentata  the  facets  are  large  and  crystalline ;  in  A.  acu- 
leata  it  is  beset  with  spicula;  and  in  A.  Jiyalina  it  is  homogeneous  and 
clear.     Vacuoles  are  seen  filled  with  coloured  vegetable  substances ;  and  in 


OF  THE  AECELLINA. 


555 


A.  vulgaris  and  other  species  a  contractile  vesicle  has  been  perceived.  The 
processes  are  longer,  as  a  rule,  than  those  of  Difflugia,  fibrous,  and  more 
branched.  The  shells  are  very  commonly  compressed,  and  have  a  discoid 
figure ;  and  in  none  are  they  soft  and  beset  with  extraneous  particles,  as  in 
Difflugia,  but  are  chitinous  and  elastic. 

"  The  Arcellce  (says  Dujardin)  seem  to  differ  among  themselves  by  the 
intimate  structiu'e  of  their  lorica,  which  sometimes  appears  membranous, 
at  others  finely  striated,  reticular,  or  with  granules  disposed  in  spiral  lines. 
Some  Arcellce  have  also  spinous  prolongations  from  the  border  of  their  lorica. 
Pressure  fractures  their  lorica  like  a  brittle  substance.  The  contained  sub- 
stance escapes  through  the  cracks  so  formed,  in  the  fonn  of  contractile  expan- 
sions like  those  of  Amoehce.  I  have  seen  one  larger  lobe  almost  separated, 
as  if  about  to  become  an  independent  being.  M.  Peltier  has  observed  con- 
tact to  take  place  between  the  expan.sions  of  neighbouiing  Arcellce  without 
any  union  being  effected,  while  the  processes  of  the  same  Arcellce  united  and 
became  blended  together. 

"  The  lorica  in  young  Arcellce  is  extremely  diaphanous  ;  and  granulations 
or  striae  are  to  be  seen  only  in  those  of  larger  size  :  hence  it  may  happen,  with 
respect  to  some  species,  that  they  represent  but  different  stages  of  existence 
of  the  same  animal." 

Ajicella  vulgaris  (xxi.  7,  8,  9).  — 
Lorica  roimd  and  bell-shaped,  with  a 
hemispherical  or  turgid  back;  smooth, 
but  with  rows  of  minute  gi'anules ;  colour 
yellow  or  ^eddish-bro^\^l.  Abimdant 
amongst  Lemnae  and  aquatic  plants. 
1-570"  to  1-240."^ 

A.  aculeata. — Yellowish,  hemisperical, 
though  often  mis-shapen,  and  spinous 
throughout,  or  only  around  one-half  of 
the  margin ;  the  shell  is  not  readily  de- 
stroyed by  heat,  and  is  covered  with 
short  spiciila.     1-210". 

A,  dentata.  —  Membranous ;   of  a  he- 


mispherical or  polygonal  form  -,  margin 
dentated;  colour  yellow  or  green. 
Amongst  Conferva.     1-570"  to  1-240". 

A.  (?)  hyalina. — Membranous,  smooth, 
elliptical  or  globular,  smaller  than  the 
preceding,  thin  and  soft,  colourless. 
Found  in  debris  at  the  bottom  of  pond- 
water,  along  with  Cypliidium  aureolum, 
&c.  1-1150  to  1-570".  The  sheU  is 
not  quite  symmetrical,  one  side  being 
more  convex  than  the  other.  Apertm-e 
sometimes  iiTegular.  Ehrenberg  was  not 
certain  that  this  species  is  not  a  Difflugia. 
It  is  indeed  very  like  many  specimens  of 
D.  Enchelys. 

A.  Americana.  —  Oblong ;  aperture 
small,  round,  not  in  the  median  line. 

A.  comtricta. — Ovate;  slightly  con- 
tracted about  the  foramen,  which'is  ver}^ 
large  and  to  one  side. 

^  A.  clisphcsra.  —  Oblong,  almost  di- 
vided  into  two  by  a  central   constric- 


tion 

large  foramen. 


one-half  nearly  occupied  by  the 
This  is  a  veiy  doubtful 
Arcella,  and  contrary  in  form  to  the 
character  of  monothalamous  cells.  A 
comparison  of  Ehreuberg's  account  with 
his  figures  leads  us  to  believe  this  sup- 
posed species  to  be  no  other  than  a  young 
Rotalia  of  two  cells  (xx.  41),  or  other 
incomplete  pol}i:halanious  shell. 

A.  ecornis. — Large;  hemispherical,  not 
areolar ;  apertm-e  roimd,  large,  placed  to 
one  side  ;  entire. 

A.  lunata. — Subglobose,  large  ;  with 
a  wide  semi-lunar  opening,  seated  to  one 
side. 

A.  Nidus-penchdm.  —  Ovate-oblong, 
hyaline,  loosely  areolated;  aperture  in 
front,  oblong,  margin  entire. 

A.  Pileus. — Hemispherical,  depressed, 
reddish,  minutely  and  elegantly  areolar ; 
aperture  central,  circidar. 

A.  ?  Globulus.  —  Subglobose ;  with 
loosely  reticular  lines,  appearing  granu- 
lar; aperture  large,  simple.  1-730".  On 
moss  at  Berlin,  Potsdam,  kc. 

A.  granulata. — Oblong,  hyaline.  Has 
the  habitat  and  size  of  A.  hyalina,  with  a 
granular  instead  of  a  smooth  surface. 
1-940".     On  moss  in  Hercynia,  &c. 

A.  caudicola. — Ovate,  oblong,  rounded 
at  each  end,  hyaline,  very  delicately 
hispid,  not  areolar;  aperture  anterior, 
round,  large.     1-840".      Habitat  of  A. 


Nidus-pendulus.     In  Venezuela,  on  roots 
of  plants,  such  as  ferns,  &c. 
A.  Okenii  (Perty)  (xxi.  15). 

Genus  CYPHIDIUM  (XXII.  24-27).— Has  only  one   dilated  variable 
process,  and  a  lorica  of  the  form  of  a  pitcher,  with  protuberances  issuing 


556 


GENERAL  HISTORY  OF  THE  ESTFtTSORlA. 


from  it.  The  lorica  is  combustible,  and  is  something  like  a  little  die  or 
stamp,  mounted  upon  a  short  stem.  It  is  very  irregularly  formed,  having 
protuberances  which  make  it  appear  four-cornered.  The  organ  of  locomo- 
tion is  a  broad  gelatinous  variable  process  with  smooth  edges,  not  urdike 
Amoeba  verrucosa.  Vacuoles  have  not  yet  been  observed ;  modes  of  propaga- 
tion unknown. 


tion  they  might  be  seen  to  change  their 
places."  Ehrenberg  only  once  perceived 
the  locomotive  organ  of  the  animalcide, 
situated  under  one  corner, — upon  which 
it  appeared  to  rest,  and  that  so  iirmly  that 
six  out  of  the  eight  protuberances  of  the 
die-like  lorica  were  visible  at  the  same 
time.  In  fig.  26  the  gelatinous  variable 
process  is  seen  projecting  from  beneath 
the  lorica.  Fig.  27  is  a  young  specimen. 
1-570"  to  1-430". 


Cyphidium  aureolum  (xxii.  24-27). — 
Lorica  cubical,  with  protuberances ;  pro- 
cess colourless.  "In  March,  1835,"  says 
Ehrenberg,  "■  I  first  observed  hundreds  of 
these  creatm^es  in  a  glass  of  water  which 
had  stood  throughout  the  winter,  in  com- 
pany with  some  specimens  of  the  Mi- 
crasterias.  Previously  to  discovering 
these,  the  Amoiba  verrucosa  had  been 
abundantly  generated,  and  afterwards 
Arcella  hyalina.  The  creatures  were  in- 
active, although   by  attentive  observa- 

Genus  TEINEMA  (Duj.). — Shell  membranous  but  resistant,  diaphanous, 
ovoid  elongated,  narrower  in  front,  with  a  large  oblique  orifice  placed  late- 
rally ;  expansions  filiform,  as  long  as  the  shell,  very  thin,  and  but  two  or 
three  in  number ;  entirely  retracted  when  others  are  to  be  pushed  out  from 
another  side.  The  animal  is  moved  onward  by  their  alternate  protrusion  and 
contraction.     This  genus  is  accepted  by  Eresenius. 

Trinema  Acinus.— Difflugia  Enchelys  (Ehr.)  (p.  553). 

Genus  EUGLYPHA  (Duj.). — Shell  diaphanous,  resistant,  membranous, 
elongated,  ovoid,  rounded  at  one  end,  terminated  at  the  other  by  a  very 
large  truncated  orifice,  with  a  dentated  margin  ;  its  surface  marked  by  emi- 
nences or  depressions,  in  regular  oblique  series ;  expansions  filiform,  nume- 
rous, simple. 

EuGLYPHA  tuberculata. — Lorica  stri-  E.  alveolata  (xxi.  11). — Lorica  with 
ated,  with  rounded  tubercles.  Termina-  regular  polygonal  depressions  in  regular 
tion  of  expansions  extremely  delicate,  oblique  (spiral)  series,  bearing  spines  at 
1-295".     Found  in  stagnant  ponds.  the  upper  or  posterior  end.     1-290". 

Genus  GEOMIA  (XXI.  12, 16)  (Duj.). — Lorica  smooth,  yellowish -brown, 
membranous,  soft,  globular,  with  a  small  round  opening,  from  which  the  very 
long  branching  expansions  proceed,  tapering  to  very  fine  extremities.  Found 
in  both  salt  and  fresh  water. 

branching  and  anastomotic.     1-865"  to 
1-520".     In  rividets. 

"  Notwithstandino-  the  absence  of  co- 


Gromia  oviformis. — Globular,  smooth, 
aperture  sorrounded  by  a  short  neck ;  ex- 
pansions very  long,  fibrous,  branching, 
slightly  anastomotic,  colourless  or  pale- 
yellow,  transparent;  animal  contents 
of  a  yellow  or  reddish-brown  colour; 
the  processes  hyaline,  permeated  by  a 
current  of  granides.  Shell  1-26"  to 
1-13". 

G.  Jluviatilis.  —  Globular,  or  ovoid, 
without  a  neck ;  expansions  palmate  and 
anastomotic.   1-290"  to  1-104". 

G.  hyalina  (Schlumberger,  A.  S.  N., 
1845,  p.  254). — Globular  or  rather  ovoid, 
smooth,  soft,  diaphanous,  colourless ; 
foramen  round,  with  a  very  short  neck, 
formed  by  a  reflexion  of  the  lorica  ;  ex- 
pansions filiform,  numerous,  very  fine. 


lour  in  the  shell,"  says  Schlumberger, 
"I  arrange  this  species  in  the  genus 
Gromia.  In  size  it  also  differs  from  the 
other  two  species.  The  lorica,  being 
transparent,  admits  to  view  some  bluish 
globules,  and  a  large  hyaline  glandular 
ovoid  body,  like  that  in  the  interior  of 
other  diaphanous  Rhizopodes." 

G.  D?yV/>Y///«V(Schidtze).— Shell  sphe- 
rical, ovoid  ;  more  constant  in  figure  than 
G.  oviformis,  colourless  or  faint  yellow, 
with  a  short  neck-like  elongation  at  the 
foramen,  or  none ;  animal  contents  dark 
sepia-brown  ;  processes  hyaline,  with  no 
moving  granules.   Diam.  1-2"'.   Ancona. 


OF  THE  ARCELLINA. 


557 


Genus  LECQUEEEUSIA  (Schliimberger).— Shell  ovo-globular,  or  retort- 
shaped,  rather  depressed,  membranous,  but  resistant ;  with  a  wide  short 
neck,  and  circular  terminal  aperture,  giving  passage  to  cylindrical  thick  and 
obtuse  expansions. 

This  genus  approaches  Difflugia  (Duj.)  in  the  character  of  its  expansions; 
but  the  veiy  different  form  of  the  shell,  and  the  position  of  the  aperture, 
sufficiently  mark  the  distinction  between  the  two.  Its  distinctness  is  re- 
garded with  doubt  by  Schultze. 


aquatic  plants,  in  many  of  the  lakes  of 
the  Jura  chain  about  Neuchatel.  Its 
diaphanous  lorica  allows  its  interior  soft 
hyaline  and  granular  body,  strewn  with 
brown  specks,  to  be  seen. 


Lecquereusia  jurassica. — Shell  re- 
sistant, diaphanous,  grey,  of  a  globular 
figure,  but  rather  depressed,  -wdth  a  short 
wide  neck.  Length  about  1-250" ;  breadth 
1-315". 

This  beautiful  species  is  met  with  on 

Genus  CYPHODERIA  (Schlum.).  —  Lorica  membranous,  resistant,  ovoid, 
elongated  anteriorly,  where  it  is  curved  and  constricted  in  the  form  of  a 
neck ;  surface  marked  by  prominent  points  in  obHque  rows ;  aperture  circular, 
oblique  ;  expansions  very  long,  filiform,  very  fine  at  the  extremity,  and  simple 
or  branching. 

The  oblique  disposition  of  the  rows  of  points,  the  obliquity  of  the  aperture, 
and  the  character  of  the  expansions,  bring  this  genus  into  affinity  with  Tri- 
nenw  (Duj.);  but  the  constriction,  forming  a  neck,  seems  sufficiently  distinc- 
tive between  the  two.  This  genus,  though  admitted  by  Eresenius,  is  treated 
as  doubtful  by  Schultze. 

Cyphoderia  margaritacea. — Lorica  i  water  oftheVosges  with  vegetable  debris. 
yeUow;  the  surface  is  divided  into  mi-  I  The  form  of  the  lorica  varies  ;  at  one  time 
nute  facets,  which  appear  like  translucent  the  neck  may  be  but  rudimentary ;  at 
points  or  rows  of  pearls.  Processes  attain  another  the  posterior  end,  instead  of 
twice  the  length  of  the  shell,  and  are  being  wide  and  rounded,  is  contracted 
simple  or  branched.  Length  1-395" ;  [  suddenly  to  a  triuicated  apex.  Aperture 
breadth  1-840" to  1-408".  Common  in  the  i  crenidate. 

Genus  PSEUDO-DIFELUGIA  (Schlum.).  —  SheU  membranous,  ovoid  or 
ovo-globular,  smooth  or  striped  spirally,  with  a  wide  round  opening,  whence 
proceed  numerous  long  slender  expansions,  either  simple  or  branching. 

This  genus  is  allied  to  Difflugia  by  the  form  and  character  of  its  shell,  but 
differs  from  it  in  the  nature  of  the  expansions ;  it  is  admitted  as  doubtful  by 
Schultze. 


filiform,  very  long.  Length  1-740"  to 
1-465";  breadth  1-890" to  1-740".  Found 
near  Mulhouse. 


PsEtrDO-DiFFLUGiA  gvaciUs.  —  Shell 
bluish  brown,  brittle  ;  surface  as  if  beset 
with  minute  grains  of  sand,  of  a  more  or 
less  elongated  ovoid  figure ;  expansions 

Genus  SPIIEN"ODEPIA  (Schlum.). — SheU  diaphanous,  colourless,  resistant, 
globular,  with  a  flattened  wedge-shaped  neck ;  surface  marked  by  polygonal 
depressions,  disposed  in  regular  oblique  rows ;  aperture  terminal,  compressed, 
almost  linear.     Expansions  filiform,  very  long  and  attenuated. 

The  form  of  the  aperture  and  of  the  neck  separates  this  genus  from  Trinema 
and  Euglypha,  to  which  it  is  allied  by  the  structure  of  its  lorica.  Schultze 
treats  it  as  a  doubtful  genus. 

Sphenoderia /ew^a. — Lorica  as  above  [  slender  and  simple,  or  branching.  1-650" 
described,    expansions   few,    very  long,  |  to  1-520". 

Of  all  the  Rhizopodes  I  have  examined  (says  Schlumberger),  this  is  the 
slowest  in  its  movements,  and  its  expansions  the  most  difficult  to  discover. 
I  have  found  it  on  tufts  of  moss  in  marshy  rivulets. 


558 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


A  glandular  body  and  hyaline  globules  are  seen  in  the  internal  soft  sub- 
stance near  the  posterior  end.  In  moving,  the  position  of  the  shell  may  be 
perpendicular,  or  oblique  to  the  sm^face  of  reptation :  the  hexagonal  depres- 
sions are  indistinct  but  large.  The  shell  fractures  along  the  lines  of  junction 
between  the  hexagons. 

Along  with  the  preceding  genera,  Schultze,  as  before  stated,  includes  in  the 
division  Monothalamia  the  new  genera  Lagynis,  Sq^iuxmulina,  and  Cornu- 
spira. 

Genus  LAGYNIS  (Schultze). — Shell  membranous,  elastic,  retort-shaped; 
body  colourless,  transj)arent ;  foramen  large,  but  the  j)rocesses  few,  very  fine, 
occasionally  branching. 

It  forms  the  type  of  the  family  LagjTiida. 


Lagynis  haltica.  — The  transparent 
contents  rarely  fill  the  shell,  but  leave  a 
space  posteriorly,  into  which  they  send 
processes  which  converge  towards  the 
summit  of  the  concavity  of  the  posterior, 
rounded  extremity.    OOo'".     Baltic  Sea. 


The  form  of  the  shell  approaches  that 
of  JEuglypha  (?)  curvata,  described  by 
Pertv^,  and  found  in  an  empty  state  by 
him  on  the  Simplon,  at  an  altitude  of 
4000  to  5000  feet. 


Genus  SQUAMULINA  (Schultze).  —  Shell  calcareous,  plano-convex,  or 
lenticular ;  adherent  by  the  plane  surface  ;  cavity  single,  one  large  opening 
on  the  convex  side ;  no  pores. 

Squamulina  IcBvis. — Ii'regularly   cir- 
cular; much  flattened;    convex  portion 


thick  and  smooth,  the  flat  portion  very 
thin  and  scarcely  separable  from  the  ob- 


ject to  which  it  adheres.  The  yellowish 
animal  protrudes  numerous  processes 
from  the  excentric  foramen.  Largest 
diam.  1-26'".     Sea- water,  Ancona. 


Genus  COllT^USPIEA  (Schultze).— Shell  calcareous,  spiral,  like  a  Pla- 
norbis  shell ;  solid  or  finely  porous  ;  discoid  ;  symmetrical,  i.  e.  with  both  sides 
alike ;  cavity  single.     One  large  foramen  at  the  termination  of  the  spii'al. 

dually  larger  towards  the  termination  of 
the  spiral ;  as  many  as  seven  tm-ns  seen. 
On  the  coast  of  Mozambique. 

D'Orbigny's  OpercuUna  inserta  is  pro- 
bably the  same  form.  The  SpinUwa  de- 
scribed by  Ehrenberg  is  somewhat  like, 
but  is  probably  only  a  young  Miliola. 


CoRNUSPiHA  planorhis. — Shell  trans- 
lucent, browTi,  without  pores;  six  or 
perhaps  more  turns  of  spiral  seen.  Mud 
from  the  coast  of  Mozambique  and 
Trieste. 

C.  perforata. — Finely  porous,  hyaline, 
colourless  \  pores  cii'cular,  becoming  gra- 


Genus  CADIUM  (Bailey)  (XXII.  19).— Shell  silicious  (chitinous ?)  ovoid; 
elongated  as  a  sort  of  neck,  which  is  bent  upwards  and  outwards,  terminated 
by  a  circular  foramen. 

This  genus  was  instituted  by  the  late  Dr.  Bailey,  of  New  York,  to  include 
some  empty  Ehizopodous  shells  met  with  in  the  soundings  taken  in  the  gulf- 
stream.     {SiUiman's  Journ.  xxii.  1856.) 


Cadium   marhmm  (xxii.  19).— Shell 
marked  by  numerous  meridian  lines,  of 


which   about   12   are   visible    at    once, 
Leng-th  2-1000" ;  diam.  I^-IOOO". 


Sub-group  ACTIXOPHEYIXA.     (Part  1.  p.  243.) 

(XXIII.  24-37.) 

A  sub-class  of  Ehizopoda  having  a  more  constant  and  definite  form,  and 
furnished  with  long  tapering  retractile  filaments  or  tentacles,  which  serve 
as  prehensile  organs,  in  the  place  of  the  usual  varial)le  processes  of  the  class. 


OF  THE  ACTINOPHRYryA.  559 

Their  movements  are  excessively  slow,  and  sometimes  inappreciable ;  and  the 
tentacles  appear  not  concerned  in  them:  conjugation  is  of  very  frequent 
occurrence. 

The  genera  enumerated  in  this  section  are  Act'inophrys,  Podophrya,  Tri- 
chodiscus,  and  Dendrosoma.  The  distinction  between  the  two  fii'st-named 
genera  is  denied  by  Stein,  and  probably  with  reason,  for  the  stem  of  Podo- 
fhrya  is  not  sufficiently  characteristic  {vide  Part  I.  p.  243).  Trichodiscus  is 
little  known  to  observers,  and  probably  is  only  a  variety  of  Actinophrys ;  and 
Dendrosoma  has  hitherto  received  little  attention  ;  its  branched  pedicle,  how- 
ever, gives  it  a  generic  importance. 

Dujardin  formed  a  very  correct  conception  both  of  the  organization  and 
affinities  of  the  Actinophrjina,  which  were  coupled  with  Amoebaea  and  Ehizo- 
poda  in  his  second  order  of  Infusoria.  He  rejected  the  genera  Podophrya 
and  Trichodiscus,  which  he  merged  in  the  genus  Actinophrys.  Siebold  very 
strangely  overlooked  the  true  structm^e  and  affinities  of  Actinophrys,  which 
he  placed  with  Enchelia,  in  company  with  the  very  dissimilar  Prorodon, 
among  his  "  Stomatoda." 

Perty  has  constituted  Actinophryina  a  second  section  of  Ciliata,  and  has 
adopted  the  genera  Actinophrys,  Podophrya,  and  Acineta.  Trichodiscus  he 
regards  as  only  a  compressed  form  of  Actinophrys,  and  treats  Dendrosoma 
as  an  aggregated  one,  in  which  the  individual  beings  are  collected  into 
colonies. 

Genus  ACTINOPHRYS  (XXIII.  28-32).— Body  more  or  less  spherical, 
usually  compressed  or  discoid,  sometimes  iiTegular  in  outHne,  owing  to  the 
projection  of  superficial  vacuoles.  Tentacles  tapering,  terminated  occasionally 
by  a  rounded  head  (i.e.  capitate),  pretty  uniformly  distributed,  their  length 
generally  exceeding  the  diameter  of  the  body ;  retractile,  and  for  a  time  lost 
in  the  substance  of  the  body,  but  reappearing  at  the  same  place  and  under 
the  same  form.  The  tentacles  serve  for  prehensile  instruments,  but  not  for 
locomotion.  Food  is  introduced  within  the  body  at  any  part,  and  not  through 
a  mouth ;  and  its  excrementitious  portion  is  in  a  similar  manner  discharged 
from  any  part  of  the  exterior.  Internally  are  one  or  two  contractile  vesicles, 
placed  immediately  beneath  the  surface,  a  nucleus  with  a  nucleolus,  ali- 
mentary vacuoles,  granules,  and  probably  smaU  nuclear  cells.  Reproduction 
takes  place  by  fission,  and  in  Dendrosoma  by  gemmation.  Germinal  deve- 
lopment is  presumed,  and  conjugation  is  a  frequent  phenomenon. 

The  proboscis  mentioned  by  Ehrenberg  appears  to  be  a  sort  of  expansion 
of  the  sarcode  of  the  body,  homologous  mth  a  variable  process,  which  enve- 
lopes and  then  drags  the  prey  into  the  general  mass. 

Ehrenberg  believed  he  had  discovered  a  mouth,  anus,  and  polygastric 
structure,  and  that  he  had  succeeded  in  demonstrating  this  last  by  feeding 
with  coloured  food.  He  hkewdse  adopted  Eichhorn's  statement — that  the 
tentacles  acted  as  locomotive  organs,  by  giving  the  animalcules  the  power  to 
crawl. 

The  specific  distinctions  hitherto  attempted  are  really  of  little  worth ;  even 
the  highest  authorities  are  in  doubt,  and  disagree  among  themselves,  respect- 
ing the  specific  names  of  the  animalcules  they  so  elaborately  describe ;  and 
the  revision  of  the  several  forms  and  varieties  of  Actinophrys  is  urgently  re- 
quired before  any  satisfactory  separation  into  species  can  be  made.  We 
append  those  forms  which  have  been  accounted  specific  by  diiFerent  authors. 

AcTiNOPimYS  Sol  (xxiii.  28,  31, 32).  I  spherical,  or  nearly  so ;  the  tentacles  or 
Colour  whitish,  or  rather  grey;  figure  j  rays  divergefrom  every  part  of  the  sm-faee. 


560 


SYSTEMATIC  HISTOKY  OF  THE  INFUSOEIA. 


and  taper  to  their  extremities,  and  equal 
the  diameter  of  the  body  in  length. 
Found  in  the  dust-like  matter  upon  the 
siu'face  of  infusions,  and  among  Confervse 
and  various  aquatic  plants.  Stein  asserts 
that  these  habitats  are  those  of  A.  Eich- 
hornii,  not  of  A.  Sol,  which  does  not  oc- 
cm*  as  a  free  being.     1-110'"  to  1-53.'" 

This  species  has  been  very  much  con- 
founded with  ^.  Eichhornii.  KoUiker  mis- 
took this  last  for  A.  Sol ;  and  Claparede 
wrote  his  description  of  A.  Eichhonu'i,  and 
afterwards  discovered  it  w^as  A.  Sol  that 
he  had  investigated.  Indeed  the  brief 
characters  furnished  by  Ehrenberg  are 
quite  inadequate  to  identify  the  species. 
A.  Eichhornii  (xxni.  29).  —  Large, 
white,  globose ;  tentacles  shorter  than 
the  diameter  of  the  body,  and  tapering. 
The  cortical  and  medullary  layers  are  well 
distinguished ;  the  former  contains  nu- 
merous vesicles.  Tentacles  contractile, 
seen  to  bend  themselves  in  the  prehen- 
sion of  food,  &c.  Stein  affirms  that  the 
being  which  Ehrenberg  described  and 
figured  under  this  name  is  no  other  than 
A.  Sol,  that  the  tentacles  are  by  no 
means  always  shorter  than  the  diameter 
of  the  body,  but  often  longer,  and  that 
this  circumstance  of  relative  length  can- 
not be  used  in  the  diagnosis  of  the  spe- 
cies, but  that  the  conical  figure  of  the 
tentacles  is  distinctive.  Stein's  views 
on  these  specific  details  must  be  re- 
ceived cum  grano  sails  ;  for  the  influence 
of  his  Aciuetiform  h}-pothesis  pervades 
his  systematic  history  of  the  beings  of  the 
class  under  notice,  and  his  figures  of  A. 
Sol  prove  him  to  have  been  in  error  either 
in  the  observation  or  in  the  interpreta- 
tion of  the  organism  ;  for  they  indicate  a 
member  of  the  Acinetina  rather  than  of 
the  Actinophryina.  Perty  seems  to  think 
the  largest  specimens  of  A.  Sol  constitute 
A.  Eichhornii  (Ehr.). 

A.  oeidata  (Stein)  (xxni.  24,  25).— 
Round,  more  or  less  discoid,  with  several 
concentric  circles  of  vesicular  spaces  dis- 
tributed over  the  smface  of  the  animal- 
cule, giving  it  an  imdulated  outline.  The 
tapering,  pointed  tentacles  arise  from  the 
eminences  of  the  smiace,  and  are  equal 
in  length  to  the  diameter  of  the  body, 
except  in  small  specimens,  in  which 
they  rather  exceed  it.  The  periphery 
of  the  body  is  covered  with  a  homo- 
geneous, transparent,  gelatinous,  appa- 
rently thick  layer,  within  which  the 
large,  vesicular,  non-contractile  spaces, 
fiUed  with  water,  are  found.  Besides 
this  superficial  layer,  a  cortical  and  a 
medullary   substance    are    clearly    pro- 


nounced. The  particles  of  food  do  not 
enter  the  medidlary  substance.  The 
finely  granular  nucleus  is  cenln-al,  sm*- 
roimded  by  a  rmg  of  clear  medullary 
matter.  Pressm-e,  after  the  action  of 
acetic  acid,  will  sometimes  detach  it  as  a 
free  body,  invested  by  a  membrane,  and 
having  within  it  an  ill-defined  granular 
nucleolus.     Diam.  1-38'"  to  1-35'". 

A.  riridis  (Ehr.). — Spherical, greenish ; 
rays  numerous,  shorter  than  the  diameter 
of  the  body.  Diam.  of  body  1-620''  to 
1-280".     Amongst  Confervae. 

A.  difformis. — Ii-regulaiiy  lobed,  de- 
pressed, and  hyaline;  rays  variable  in 
length,  some  exceeding  the  diameter  of 
the  body,  which  is  from  1-570"  to  1-280". 
The  animalcule  thus  described  Stein  ap- 
prehends to  be  nothing  more  than  several 
young  specimens  of  A.  Eichhornii  con- 
joined (conjugated). 

A.  mar  ilia  (Duj.). — Differs  from  A.  Sol 
in  its  habitat,  and  in  the  more  marked 
contractility  of  its  rays.  Amongst  micro- 
scopic Algae  in  the  Mediterranean.  Pro- 
bably a  mere  variety  of  A.  Sol. 

The  claim  of  A.  riridis,  A.  difformis, 
and  A.  marina  to  specific  distinction  is 
extremely  doubtful.  The  green  colour 
of  the  first  is  immaterial,  and  the  rela- 
tive length  of  its  rays  to  the  body  of  no 
specific  importance.  The  in-egularly- 
lobed  outline  of  A.  difformis,  again,  is  an 
immaterial  condition  -,  for  the  soft  bodies 
of  true  Actinophryina  admit  a  changeable 
outline,  and  the  reception  of  food,  more- 
over, to  a  certain  extent  involves  it. 
Dujardin  justly  attributes  no  other  value 
to  his  species  A.  marina,  than  that  it 
may  serve  to  indicate  an  Actinophrys 
living  in  the  sea. 

A.  }iedicellata  iJ)u].)  =  PodophrijaJixa. 

A.  dirjitata. — (Duj.). — Depressed;  rays 
flexible,  thicker  at  the  base,  fonning, 
when  contracted,  short,  thick,  finger- 
like processes.  Diam.  1-750".  In  fresh 
water  containing  marsh-plants.  Its  dis- 
coid body  woidd  rather  place  it  with 
Trichodiscus. 

A.  f/ranata  (Duj.)  (Trichoda  graiiata, 
M.).— Globular,  opaque  at  its  centre,  stir- 
rounded  by  rays  of  less  length  than  its 
own  diameter. 

A.  Discus  (J)\\].)  =  Trichodiscus  Sol 
(Ehr.). 

A.  ovata  (Lachmann).  —  A  species 
named  by  this  naturalist  in  A.  N.  H. 
1857,  xix.  p.  221. 

A.  hrevicirrhis  (Perty).— Of  a  dusky 
yellowish  green  colour,  rarely  colourless ; 
tentacles  much  shorter  than  the  diameter 
of  the  bodv ;  not  capitate,  but  bristle- 


OF  THE  ACTHSrOPHRYINA. 


561 


like.  Its  outline  is  double,  with  a  green 
or  red  line.  Length  1-GOO"  to  1-500"- 
Bern.     Among  Confervae. 

A.  Stella  (Perty)  =  Tn'ckodiscus  Sol.— 
It  is  to  be  regretted  that  Perty,  whilst 


recognizing  this  organism  to  be  an 
Actinophrys,  should  not  have  adopted 
Dujardin's  very  appropriate  name  for  it, 
rather  than  encumber  the  student  -udth 
another. 


Genus  TRICHODISCUS. — Body  depressed,  with  a  single  marginal  row  of 
setaceous  tentacles ;  vibratile  cilia  and  teeth  absent ;  no  pedicle ;  mouth 
truncated  (Ehr.). 

These  Infusoria,  by  their  flat  disciform  shape,  resemble  Arcelhe,  but,  un- 
like the  latter,  are  soft  and  illoricated,  with  stiff,  bristle-like  rays.  A  central 
opening,  and  a  large  lateral  gland  (nucleus),  have  been  recorded  by  Ehren- 
berg,  who  likewise  states  that  he  has  seen,  though  indistinctly,  numerous 
digestive  cells,  but  neither  the  reception  of  coloured  food,  nor  an  anal  orifice. 

This  account  is  very  unsatisfactory  as  a. means  of  determining  a  genus. 
The  discoid  figui'e  is  not  a  sufficient  distinction  from  the  genus  Actinophrys ; 
and,  on  the  other  hand,  the  softness  of  the  integument,  compared  with  the 
lorica  of  Arcella,  is  not  a  generic  distinction ;  for  the  so-caUed  lorica  of  the 
latter  genus  is  in  many  instances  only  a  flexible  integument. 

Cohn  (Zeitschr.  1853,  Band.  iv.  p.  262),  after  remarking  on  certain  Acti- 
nophiyean  beings  covered  wdth  adherent  foreign  particles  of  sand,  Cyclo- 
tella-sheRs,  tfec,  and  surmising  that  such  beings  were  no  other  than  Diffluyice 
engaged  in  the  formation  of  a  lorica,  submits  the  opinion,  in  a  foot-note,  that 
Trichodiscus  Sol  (Ehr.)  is  a  similar  organism,  because  Ehrenberg  describes  its 
tentacles  as  proceeding  from  the  middle  of  the  body,  which  is  often  partially 
coloured  with  brownish  corpuscles. 

Trichodiscus  Sol   (Actinophrys  Dis-  I  Amongst    Confervas.      Diam,,    without 
cvs,J).). — Depressed,  almost  flat,  hyaline    rays,  1-430"  to  1-210". 
or  yello\\ash,  with  variable  rays.     The        Perty,  as  already  seen,  retains  this  spe- 
motion  of  this  species  is  very  sluggish  ;     cies  with  Actinophrys,  with  the  name  of 
it  often  remains  for  a  long-  time  inert.  I  A.  Stella. 


Genus  PODOPHRYA  (XXIII.  34-37).— The  members  of  this  genus  differ 
from  Actinophrys  only  in  being  stalked.  Stalk  single,  not  branched.  Eh- 
renberg described  them  as  Enchelia  devoid  of  vibratile  cilia  and  teeth,  with 
spherical  bodies,  covered  with  setaceous  tentacles  ;  having  a  truncated  (direct) 
mouth  ;  and  in  organization  equivalent  to  Actinophrys,  with  a  stiff  stalk. 


PoDOPHRYA  ovata  (Alder).  —  Body 
ovate,  with  a  very  slender  and  short 
stem  ;  tentacles  capitate,  retractile,  in  a 
single  row,  less  numerous  than  in  JSphe- 
lota  apiculosa,  and  forming  a  narrow  disc. 
Parasitic  on  Sertularice. 

P-  pyriformis  (Alder). — Body  pear- 
shaped,  or  rather  campanulate,  with  a  di- 
stinct rim  around  the  summit,  and  a  sin- 
gle circlet  of  delicate,  capitate,  retractile 
tentacles;  stem  long  and  slender.  Pa- 
rasitic on  Paludicella,  and,  milike  the 
preceding,  an  inhabitant  of  fresh  water. 

These  two  species  were  first  described 
by  Mr.  Alder,  along  vnih  Ephelota  apicu- 
losa,  and  were  described  in  the  previous 
edition  of  this  work,  under  the  name  of 
"  Alderia."  Lately,  however,  Mr.  Alder 
wi-ote  to  inform  us  that  this  name  had 
been  applied  to  a  difterent  class  of  ani- 


mals, and  therefore  could  not  be  retained. 
Dr.  Strethill  Wright  has  since  studied 
these  beings,  and  distinguished  one  as 
Ephelota  apicidosa,  and  placed  the  other 
two  among  Podophryce.  Mr.  Alder  (A. 
N.  H.  1851,  Y\\.  p.  427)  recognized  their 
relation  to  Acinetc?,  and  their  afhnit}^ 
to  Campanularian  Zoophytes,  between 
which  and  Infusoria  he  considered  them 
the  most  perfect  link  known. 

V.  Jixa  {Trichoda  jixa,  M.  Actino- 
phrys pedicelhda,  D.). — Body  spheiical, 
turbid,  whitish,  with  a  diaphanous  pe- 
dicle slightly  excised  at  the  extremity. 
The  rays  or  tentacles  are  capitate  at  the 
extremity,  and  equal  in  length  the  dia- 
meter of  the  body.  Ehrenberg  states 
that  the  seizing  or  catching  power  of 
this  animalcule  is  very  interesting  to  ob- 
serve. So  soon  as  a  quickly-vibrating 
2  0 


562 


SYSTEMATIC  HISTORY  OF  THE  OFUSOKIA. 


Trichodina  Grcwdinella  approaches  to,  aiid 
comes  in  contact  with,  its  teutaciila,  it 
is  immediately  taken  prisoner,  ceases  to 
vibrate,  and  stretches  out  its  cilia  back- 
wards. On  the  whole,  this  species  re- 
sembles Acineta;  but  Ehrenberg  sup- 
posed it  to  possess  a  discharging  orifice, 
though  its  situation  is  unknown.  Found 
among  dust-like  matter  upon  the  surface 


of  pond-water,  "  and  perhaps,"  sa^'S  Ehr., 
^'  also  in  the  sea."     Diam.  1-430''. 

P.  libera (Perty). — Stemless, spherical; 
colom*less,  or  faint  yellow;  periphery 
smooth;  tentacles  hyaline,  pointed  in 
greater  or  less  number,  many  very  lono-, 
sometimes  very  few  present,  many  seen 
curved.  Diam.  1-330".  In  stale  pond- 
water. 


Claparede  and  Lachmann  have  recently  (Ann.  d.  Sc.  Nat.  1857)  distin- 
guished a  number  of  species  of  Podophrya,  many  of  which  would  be  accoimted 
Acinefce  by  Stein ;  however,  they  have  no  capsule  like  members  of  that  genus. 
No  characters  are  given.  The  following  are  noted:  —  1.  Podophrya  Oy- 
dopum,  parasitic  on  Cyclops  and  Lemna3;  2.  P.  Carchesii,  on  Carchesium 
polypinum  ;  3.  P.  quadripartita,  the  same  as  the  Acineta  assigned  by  Stein 
to  EpistyJis  pUcatilis ;  4.  P.  Pyrum,  a  large  form,  pear-shaped,  found  on 
Lemna  trisulca ;  5.  P.  cotJmrnata,  the  diademiform  Acineta  of  Stein ;  6.  P. 
Ferrum-equinum,  the  Acineta  of  the  same  name  of  Ehr. ;  7.  P.  Lynghyei,  the 
Acineta  Lyngbyei  (Ehr.) ;  8.  P. ,  a  marine  form,  with  extremely  dila- 
table suckers. 

Genus  DENDEOSOMA*  (Ehr.). — This  includes  beings  which  resemble 
Actinophrys,  supported  on  a  branching  pedicle.  The  base  of  the  thick 
pedicle  or  trunk  is  fixed  ;  and  its  divisions  bear  the  animalcules  at  theii'  ex- 
tremities. In  appearance,  therefore,  it  resembles  a  microscopic  Sertularian 
polype. 

The  question  ma}^  be  raised,  if  this  genus  is  not  the  same  as  Anthophysa 
(p.  500),  misinterpreted  in  structure ;  and  if  the  organisms  terminating  the 
branches  are  not  Uvellce  instead  of  Actinophrydes. 

Dendrosoma  radians.  —  Corpuscles  I  tentacula;  disposed  on  a  soft,  smooth,  and 
(animalcules)    conical,    furnished   -u-ith  |  alternately  branched  stem.     At  Berlin. 

Genus  EPHELOTA  (Wright). — Similar  to  Podophrya ;  but  the  tentacles, 
instead  of  being  capitate,  are  pointed,  and  form  a  wreath  or  circlet.  They 
seem  also  to  be  either  slightly  contractile  or  retractile,  or  only  flexible. 
Pedicle  composed  of  a  cortical  matter  or  integument,  and  a  medullaiy  or 
contained  substance. 

formed  of  circular  fibres  passing  at  right 
angles  to  the  fibres  of  the  medulla,  which 
cortical  fibres  are  absent  in  E.  coronata. 
E.  coronata  (Wright). — Body  consists 
of  a  short  cylinder  of  densely  granidar 
sarcode,  slightly  enlarged  above  and  be- 
low, so  as  to  resemble  the  circlet  of  a 
crown.  It  is  surmoimted  by  a  circle  of 
thick,  acuminate  and  radiating  tentacles, 
which  are  capable  of  being  slowly  cm-ved 
inwards,  but  cannot  be  contracted.  They 
remain  stifliy  extended  when  the  animal 
is  immersed  in  alcohol.  The  structure  of 
the  tentacles.  I  believe,  is  imique.  Under 
high  microscopic  power  they  are  seen  to 
consist  of  a  bundle  or  framework  of  fine 
parallel  rods  of  horny  (?)  texture,  imbed- 
ded in  soft  contractile  sarcode.  The  more 
central  rods  of  the  bundle  protrude  con- 
tinuallv  beyond  those  exterior  to  them, 


Ephelota  ajncuhsa. — Body  vase-  or 
cup-shaped,  expanded  at  top  and  set 
round  with  several  circlets  of  numerous 
pointed  tentacles ;  abruptly  thickened  to- 
wards the  base.  The  tentacles,  which 
are  ahvays  in  more  than  one  row,  enjoy 
little  motion,  curve  themselves  forward 
occasionally,  and  are  slowly  retracted  at 
times.  Pedicle  stout.  Found  parasitic 
on  Sertularia  ;  by  Dr.  Wright  on  Corijne. 

It  diff'ers  from  JE".  coronata  in  having  the 
body  wider  than  the  stem,  more  cup- 
shaped  and  elongated,  and  the  tentacles  j 
more  irregular,  soft,  retractile,  and  unsup- 
ported by  the  solid  matter  which  occurs 
in  the  interior  of  those  of  the  species 
named.  It  is  especially  distinguished  by 
the  shape  and  structure  of  the  stem, 
which  is  of  nearly  equal  diameter  through  - 
out,  and   encloses   a   cortical  substance 


OF  THE  ACTINOPHRTINA. 


563 


SO  that  the  point  of  the  tentacle  is  formed 
of  only  a  veiy  small  number.  In  other 
examples,  each  rod,  under  a  power  of  800 
diam.,  assumed  a  bearded  structure. 

"The  animal  secretes  beneath  itself, 
or  from  its  base,  a  pedicle  of  diaphanous 
and  colourless  substance,  which  increases 
in  length  and  breadth  with  the  increasing 
growth  of  the  animal,  until  it  assumes 
the  form  of  a  glassy  club,  on  the  thick 
upper  extremity  of  which  the  animal 
is  seated.  The  whole  of  the  pedicle 
is  covered  by  a  growth  of  scattered 
hairs;  but  it  may  be  doubted  whether 
these  have  any  organic  connexion  with 
it,  and  whether  they  do  not  belong  to 
one  of  those  minute  classes  of  Algae  the 
structure  of  which  eludes  microscopic 
research.  A  longitudinal  fibrous  struc- 
ture is  faintly  seen  in  the  axis  of  the 
pedicle,  but  it  gradually  disappears  to- 


wards the  periphery.  After  immersion 
in  spirit,  this  fibrous  structure  becomes 
much  more  apparent.  The  action  of  the 
spirit  also  causes  a  fine  membrane  to 
separate  from  the  surface  of  the  pedicle, 
which  appears  to  be  continued  down- 
wards from  the  body  of  the  animal,  and 
is  probably  analogous  to  the  membrane 
which  I  have  already  shown  to  exist  as 
a  lining  and  covering  to  the  cell  of  Va- 
ginicola  valvata,  and  which  secretes  and 
hides  within  itself  the  valve  that  closes 
the  cell  of  that  curious  animal  "  {^Edin. 
New  Phil  Journ.  1858,  p.  7). 

This  species  was  twice  seen  by  Dr. 
Wrig'ht,  "  each  time  in  large  colonies, 
situated  within  the  mouth  of  shells  in- 
habited by  the  hermit-crab,  where  the 
dense  white  bodies  of  the  animalcules, 
seated  on  their  transparent  pedicles,  form 
sufficiently  remarkable  objects." 


Genus  ZOOTEIREA  (Wright)  (XXXI.  14-15).— Body  furnished  with 
numeroiLS  contractile  acuminate  rays  (tentacula) ;  elevated  on  a  contractile 
pedicle.  Rays  becoming  thickened  towards  the  point  when  not  fully  ex- 
tended, but  not  capitate. 


ZooTErREA  religata  (xxxi.  14-15). — 
The  body  of  the  animalcule,  when  con- 
tracted, consists  of  densely  granular  sar- 
code  smTounded  by  a  layer  of  more 
transparent  substance.  This  external 
coat  is  capable  of  being  prolonged  into 
innumerable  exceedingly  attenuated  ten- 
tacles or  rays,  from  eight  to  ten  diameters 
of  the  body  in  length,  and  resembling  in 
structm^e  those  QiEpJielota  apicidosa.  The 
animalcule  is  elevated  on  a  lono-  contrac- 


continuous  with  the  external  coat  of  the 
body.  1  have  several  times  seen  this 
animal,  always  in  colonies.  When  seen 
by  oblique  illumination,  it  has  a  very 
striking  appearance.  The  light  reflected 
from  tlie  rays  has  the  appearance  of  two 
cones  issuing  on  opposite  sides  of  the  body, 
and  rotating  in  opposite  directions  with 
every  movement  of  the  lamp.  Found  on 
shells  dredged  from  deep  water  in  the 
Firth  of  Forth. 


tile  pedicle,   which  appears  also  to  be  I 

We  are  indebted  to  Dr.  Strethill  Wright  of  Edinburgh  for  the  knowledge 
of  this  genus  and  species.  Dr.  Wright  was  so  kind  as  to  transmit  the 
account  to  us  in  manuscript,  together  with  notes  on  Ephelota,  the  characters 
of  the  folloTvdng  pecuhar  genus  Corethria,  and  those  of  several  additional 
Infusoria. 

Genus  CORETHRIA  (Wright)  (XXXI.  5,  6).— The  history  of  this  genus  is 
thus  described  (in  Uteris)  by  its  discoverer,  in  the  details  of  the  structure  of  the 
only  species  yet  found,  viz. : — "  Coy^etliriaSertularice  consists  of  a  body,  or  oblong 
cushion-hke  mass  of  granular  sarcode,  furnished  with  a  long  club-shaped 
appendage,  which  bears  at  its  summit  a  thick  bnish  of  tentacles.  The  body 
is  generally  homogeneous,  although  occasonally  one  or  two  large  cells  are 
seen  within  it.  The  mop-like  appendage  is  seen  to  contain  two  structures, 
both  without  granules.  The  interior  or  medullary  portion  is  a  transparent 
and  structureless  cylinder,  arising  from  a  slight  depression  in  the  body  of  the 
animal.  The  exterior  structure,  also  transparent,  is  transversely  wrinkled  or 
rugose.  The  tentacles  are  transparent,  from  eight  to  about  forty  in  number, 
and  have  occasionally  a  slight  waving  motion :  they  appear  to  arise  from  the 
internal  lamina  or  core  of  the  mop.  A  second  kind  of  appendage  is  frequently 
found  attached  to  the  body  of  Corethria,  in  the  form  of  a  long  spindle-shaped 

2o2 


564  SYSTEMATIC  niSTORY  OF  THE  INFUSOKTA. 

mass  of  granular  sarcode,  similar  to  the  body,  having  a  depression,  perhaps  an 
orifice,  at  its  distal  end.  This  is  either  a  pamsite  or  a  gemma,  as  it  is  some- 
times found  attached  alone  to  the  Sertularia.  It  appears  to  multiply  by 
fission,  as  two  are  sometimes  found  attached  together." 

In  another  letter,  Dr.  Wright  remarks  that  he  has  "  doubts  as  to  the  Gre- 
garina-like  body  being  a  part  of  the  animal,  as  it  is  often  absent,"  and  he  has 
"  seen  it  fij(:ed  to  neighbouring  bodies."  Food  is  probably  taken  up  by  the 
summit  of  the  mop-like  process,  absorbed,  and  carried  down  to  the  body. 

Dr.  Wright  has  found  this  remarkable  animalcule  three  successive  years  at 
Granton,  in  great  abimdance,  though  in  a  limited  locality.  It  occui^s  at  all 
parts  of  the  polj^Didom  of  the  Sertularia  pumila,  but  chiefly  in  the  angle 
between  the  mouth  of  one  cell  and  the  lower  part  of  the  cell  above,  where 
two  or  three  sometimes  nestle  together. 

Although  unhke  all  other  animalcules  in  shape,  Dr.  Wright  is  induced  by 
its  stnicture  to  place  it  near  Actinoplirys.  AYere  it  not  for  the  cushion-like 
body,  the  mop-headed  process  would  be  referable  to  Ejilielota. 


Subgroup  ACINETINA.     (Part  I.  p.  258.) 

(Plates  XXIII.  1-27;  XXVI.  3-4;  XXVII.  13-15,  18-20; 
XXX.  3,  4,  8,  21-23.) 

A  subclass  of  PJiizopoda,  very  closely  resembling  Actinophryina,  but  covered 
by  an  integument  or  capsule,  tlu^ough  which  the  retractile  tentacula  or  fila- 
ments are  protruded,  and  usually  supported  on  a  pedicle. 

The  Acinetce  have  been  supposed  to  have  no  power  of  nourishing  them- 
selves by  absorption  of  foreign  matters  from  without,  as  do  the  Actinophryina ; 
but  this  seems  to  be  an  error ;  and  Lachmann  asserts  them  to  be  peculiarly 
carnivorous  animals,  the  prey  being  seized  by  the  tentacula,  which  have 
suctorial  extremities. 

The  researches  of  Stein  went  to  show  that  the  members  of  this  family  were 
nothing  more  than  a  developmental  phase  of  VorticeUina ;  but,  although  this 
view  has  been  accepted  by  a  few  naturalists,  it  has  been  pretty  successfully 
controverted  by  Lachmann,  Claparede,  and  others,  who  have  witnessed  the 
reproduction  of  Acmetoi  from  parent  forms. 

The  tentacles  of  Acinetina  are  not  as  a  rule  capitate ;  many  taper,  others 
are  of  nearly  the  same  width  thi'oughout.  They  may  be  distributed  pretty 
generally  over  the  body,  or  only  along  a  certain  margin,  or,  again,  may  be 
collected  into  several  bundles. 

To  represent  the  known  specimens  of  Acinetiform  beings,  we  shall  describe 
all  those  varieties  described  by  Stein  ;  for  the  truth  or  error  of  his  hj^Dothesis 
of  transfoiTuation  does  not  affect  the  value  of  his  descriptions  of  them  as 
distinguishable  forms  of  organized  beings.  But  before  entering  on  the  account 
of  these,  we  shall  reproduce  the  species  enumerated  by  Ehrenberg  under  the 
head  of  Acineta. 

Genus  ACINETA. — Has  a  membranous  lorica,  a  simple  pedicle,  and 
numerous  retractile,  non-^-ibrating  tentacula.  Ehrenberg  notes  his  dis- 
covery of  vesicles  (stomach-cells)  in  A.  Lynghyei  and  A.  mystacina,  and  of  a 
nucleus  in  the  latter  and  in  A.  tuherosa.  Self-di^-ision  not  observed.  Keijro- 
duction  by  germs,  noticed  by  Stein,  Cienkowsky,  Lachmann,  and  others. 

Acineta  Lymjhyei.  —  Spherical,  pe-  |  pale-yellow  coloured  body,  with  its  thick 
dide  thick.  It  resembles  a  stalked  Ac-  crystalline  stalk,  is  similar  to  a  retracted 
tinophrys,  while  the  circular,  radiating,  I  VorticeUa.      On    Serttdaria    and    other 


OF  THE  ACINETINA. 


oijo 


Polypes.  This  is  called  a  Podoplirya 
by  Lachinann.  Length,  including-  stalk, 
lll70"  to  1-100". 

A.  tuber osa  (Vorticella  ticbcrosa,  M.) 
(xxvi.  3-4). — Triangidar,  compressed ; 
dilated  and  truncate  anteriorly,  with 
three  obtuse  tubercles  or  horns,  of  which 
the  two  lateral  are  more  constant,  and 
furnished  with  tentacula.  Pedicle  simple 
and  slender.  1-210"  to  1-100".  In  marsh- 
aud  sea- water ;  on  Ceramium  diaphamim 
(XXI.  3-4).  See  account  of  Acinda  of 
ZootJiamnium  ajfine. 

A.  mystacina  (x.  205). — Subglobose, 
obtusely  horned,  with  two  elongated 
bundles  of  tentacida:  pedicle  slender. 
Upon  Lemna  minor.    1-800"  to  1-120". 

A.  Ferrum-cquinum  (xxiii.  26,  27). — 
Oyate,  white,  tentacula  disposed  at  its 
front;  pedicle  small,  thick;  a  central 
gland  ofa  horse-shoe  shape.  1-240".  Ber- 
lin.    This  Lachmann  calls  a  Podoplirya. 

A.  (?). — Brightwell  describes  an  ani- 
malcule with  an  oyal  sheath,  of  a  dark 
colour,  opake  and  granulated,  and  having 
a  bundle  of  diverging  rays  proceeding 
from  each  extremity,  many  of  which,  by 
conti'action  or  otherwise,  have  a  globular 
tip.  They  were  not  observed  to  move  or 
catch  other  animalcules.  In  fresh  water 
at  Oulton,  Norfolk. 

A.  patula. — A  species  mentioned  by 
Lachmann  {A.  S.  N.  1857)  as  developing 
embryos,  and  common  on  Algte  and 
Zoster  a  found  on  the  coast  of  Norway. 

A.  Cucullus. — Another  species  named, 
and  not  described,  by  the  same  naturalist. 
Foimd  in  the  Fj  ord  of  Bergen. 

A.  cylindrica  (Perty).  —  Colourless, 
transparent,  cylindrical,  supported  on  a 
short  stem.     1-22"'. 

CotJiurma  maritima.  —  Its  presumed 
Acineta  bore  a  close  resemblance  to  Ad- 
nata tuberosa  (Ehr.).  It  had  a  moderately 
long,  thin  stalk,  not  dilated  upwards ;  and 
the  body  was  enclosed  by  a  hyaline  cap- 
sule, capped  by  a  conical,  roof-like  por- 
tion, from  which  the  inverted  conical  or 
pyriform  granular  body  was  suspended, 
more  or  less  space  intervening  between 
it  and  the  capsule.  From  each  external 
anterior  an^le  proceeded  a  bundle  of 
gently-tapering,  line,  and  slightly  capi- 
tate tentacles,  retractile  and  divergent. 
Internally  was  a  round  contractile  space 
and  an  oval  nucleus, 

Epktylis  branchhphila.  — The  Acineta 
assigned  to  it  by  Stein  has  usually  a  short, 
slightly  cuned,  stiff  and  solid  pedicle, 
always  much  thinner  than  the  stem  of 
the  fyistylis  itself.  Figure  pyriform  ;  two 
bundles  of  bristly,  non-capitate  tentacula 


given  off  from  its  anterior  end.  The  body 
exhibits  constant  changes  in  outline  by 
the  vermicidar  contractions  of  its  tissue, 
and  likewise  alters  its  relative  position 
with  its  stem.  It  likewise  exhibits  trans- 
itory folds,  swellings,  and  inflations  of 
the  surface.     1-240". 

E.  crassicolUs. — Stem  of  its  Aci?ieta 
transversely  striped,  crystalline,  mostly 
straight,  and  generally  like  that  of  the 
Epistylis  itself,  except  in  thickness,  being 
in  this  respect  much  thinner,  save  at  its 
expansion,  supporting  the  body  of  the 
Acineta.  This  last  is  of  a  rectangular 
iigure,  with  rounded  angles,  and  often 
inflated  at  the  middle.  Tentacula  taper- 
ing, capitate,  always  few  in  number — 
from  two  to  four  at  each  of  the  four 
angles,  and  always  longer  than  the  dia- 
meter of  the  body.  Length  (maximum ) 
of  body^l-30"',  breadth  1-28"'.  Found 
on  the  Entomostraca. 

E.  plicatilis.  — Acineta-'^e&\c\Q  solid, 
longitudinally  striated,  much  narrower 
than  stem  of  the  Epistylis,  except  at  its 
upward  dilatation,  where  the  body  was 
affixed.  Body  pyriform  or  ovoid,  com- 
pressed ;  in  most  specimens  with  a 
smooth  surface  and  no  tentacida :  when 
the  last  were  present  they  were  small, 
capitate,  and  few  in  numlDer,  and  col- 
lected in  four  bundles,  one  on  each  lobu- 
lar expansion  of  the  then  expanded  Aci- 
neta. Maxim,  length  1-16'",  width  1-20'". 

Opercularia  articulata  (xxx.  3-4). — 
Pedicle  of  Acineta  rigid,  solid,  thin, 
mostly  curved,  and  shorter  than  the 
body.  After  a  certain  height  (about 
the  half)  it  suddenl}^  and  gTeatly  ex- 
pands to  its  point  of  articulation  wdth 
the  body.  It  is  striated  longitudinally, 
and  hyaline.  Body  compressed,  with  a 
circular  outline,  or  discoid,  ovoid,  or  py- 
riform figure.  Abruptly  and  widely  trun- 
cate at  its  base,  where  it  is  fixed  on  its 
pedicle :  siu-romided  by  an  apparently 
firm  and  thick  integument,  without 
aperture,  and  covered  at  slight  intervals 
by  short,  thick,  tubular  and  undulating- 
tentacles.  Maximum  length  1-20'"  to 
1-12'",  width  1-14'"  to  1-24'". 

O.  berberina  (xxiii.  17-20). — Stem  of 
Acineta  very  short,  thick,  solid,  smooth 
or  transversely  striped,  usually-  con- 
tracted in  the  centre  and  dilated  at  each 
end.  The  stem  supports  a  very  large, 
flattened,  discoid  capside,  with  a  para- 
bolic outline,  and  having-  a  gently  curved 
anterior  double  margin  enclosing-  an  open 
space.  The  margins  are  comparable  to 
a  front  and  back  lip :  the  walls  of  the 
capsule  thick,  flexible,  and  hyaline.     A 


566 


SYSTEilATIC  HISTORY  OF  THE  rN^FUSORIA. 


portion  of  the  eontaiued  Acineta-hody 
extends  beyond  the  lips  like  a  tongue. 
This  process  contains  from  foiu*  to  five 
contractile  spaces,  variable  both  in  posi- 
tion and  size,  as  M-ell  as  changeable  in 
figure,  from  a  circular  to  a  dumb-bell 
shape.  The  rounded  anterior  angles  of 
the  proicess  support  numerous  radiating 
tubular  tentacles,  neither  capitate  nor 
tapering,  but  retractile  and  capable  of 
being  collected  together  in  cylindrical 
bundles.  The  tentacles  may  be  retracted 
within  the  lips  of  the  capsular  opening ; 
and  when  this  happens,  the  anterior  mar- 
gin of  the  Acineta  has  a  trilobate  cha- 
racter ;  and  veiy  fr'equently  a  transverse 
fold  makes  its  appearance  behind  the 
middle  of  the  body,  and  might  easily  be 
mistaken  for  an  indication  of  commenc- 
ing transverse  fission.  Sometimes  two 
such  folds  are  displayed.  Maximum 
length  of  capsule  1-14'",  width  across 
the  anterior  labiate  extremity  1-19'" ; 
length  of  pedicle  1-125'". 

In  figure  and  other  respects  this  Aci- 
neta, remarks  Stein,  difiers  so  mate- 
rially from  those  of  other  Acinetina, 
that,  if  these  beings  are  to  be  considered 
independent  organisms,  it  would  require 
the  creation  of  a  new  genus. 

O.  Lichfensteinii  (xxiii.  22-23).— The 
Acineta  varies  very  much  both  in  figure 
and  dimensions.  All  varieties  have  a 
short,  thick,  solid  stem,  dilating  upwards 
to  the  body  of  the  animal.  "When  largest, 
it  equals  half  the  length  of  the  body, 
but  is  at  times  so  short  that  the  body 
seems  as  if  sessile.  The  body  is  usually 
strongly  compressed  laterally,  and  in 
outline  is  a  long  or  short  oval,  ovate, 
pp'iform,  or  circular,  except  that  in  all 
cases  it  is  narrowed  at  its  base  to  equal 
in  width  that  of  the  supporting  pedicle. 
In  short-stalked  smaller  individuals,  the 
body  is  mostly  so  very  shortened  and 
depressed,  in  its  long  axis,  that  the  stem 
is  quite  overlaid,  and  the  entire  being 
has  a  renifonn  shape.  A  circular  or  oval 
nucleus  occurs  in  the  interior,  but  no 
contractile  sac  was  discoverable.  Maxi- 
mum length  1-18'",  width  1-24'",  dia- 
meter of  smallest  specimens  1-96'". 

Ophrydium  versatile  (xxx.  8). — Stein 
does  not  appear  satisfied  with  regard  to 
the  Acinetiform  being  to  be  assigned  to 
this  member  of  the  Vorticellina  (Ophrj-- 
dina).  He  found  many  cystic  oval  or 
ovoid  bodies,  with  an  iri-egular  central 
nucleus  and  numerous  chlorophyll-cor- 
puscles in  company  with  tliis  O^jhri/dium  ; 
and  along  with  these,  which  he  concluded 
to   be  encysted   beings,   other    saccular 


organisms,  of  like  size  and  figure,  con- 
taining also  a  central  nucleus  and  many 
chlorophyll  cells,  and  withal  furnished 
with  a  large  number  of  tapering  tubular, 
mostly  curved  or  contorted,  motionless 
processes  or  tentacles,  distributed  over 
the  surface,  recalling,  in  general  appear- 
ance, the  "  digitate  Acineta.'' 

Sjnrochona  gemmipara  (xxx.  21-24). 
— Stein  assigns  to  this  peculiar  member 
of  the  Vorticellina  a  very  extraordinary 
Acineta,  which  he  has  named  Dendro- 
cometes  paradoxus.  The  body  is  plano- 
convex, circular,  without  pedicle,  and 
gives  oft'  from  its  surface  no  tentacles  of 
any  of  the  ordinary  types,  but  one  or 
more  large  tubular  processes,  more  or 
less  branched.  There  is  so  great  an  in- 
constancy in  the  number,  position,  size, 
and  ramification  of  these  processes  (says 
Stein),  that  two  similar  specimens  are 
scarcely  to  be  foimd.  The  processes  on 
the  same  being  difter  also  very  much  in 
size  and  mode  and  degree  of  branching. 
Five  is  the  prevalent  number  in  the 
most  fully  developed  forms  j  above  six 
are  scarcely  ever  seen ;  three  or  four  are 
not  uncommon ;  a  single  one  is  seen  only 
in  undeveloped  examples.  An  entire  ab- 
sence of  such  appendages  is  not  very 
uncommon,  the  nuclear  developments  in 
their  interior  ser\'ing  to  identify  them. 
Neither  their  trunk-like  process  nor  any 
of  its  ramifications  has  the  power  of 
lengthening  or  shortening  itself;  but  the 
whole  process  may  imdergo  a  certain 
amount  of  curvature,  and  extend  itself  in 
a  rigid  manner.  Diameter  of  body  1-54'" 
to  1-25"'. 

Notwithstanding  the  very  patent  di- 
versity in  form  and  constitution.  Stein 
declares  these  tubular  ramified  processes 
to  be  moi-phologically  and  physiologically 
identical  with  ordinary  tentacula. 

Vaginicola  crystallina  (xx^ai.  12-15). 
— The  Acineta  attributed  to  this  being 
by  Stein  has  a  hyaline  capsule,  expanded 
in  front  and  narrowed  posteriorly  into  a 
sort  of  hollow  pedicle.  The  dilated  upper 
portion  is  infundibuliform,  urceolate,  or 
p}Tiform  in  figure,  and  is  partially  occu- 
pied by  the  granular  mass  of  the  body  of 
the  animalcule,  enclosed  in  a  membra- 
nous sac  of  its  own.  The  body  is  sus- 
pended from  the  vaulted  anterior  sm*face 
of  the  capsule  by  an  intermediate  gela- 
tinous layer,  which  often  appears  pli- 
cated. Its  bulk  varies  extremely ;  at 
times  it  nearly  occupies  the  whole  ca\ity 
of  the  capsule,  except  the  prolonged 
stem-like  portion,  which  never  contains 
anv  ;  at  others  it  forms  onlv  a  small  ball 


OF  THE  ACINETIXA, 


567 


at  the  anterior  end,  wliicli  is  then  con- 
tracted npon  it  by  being  thrown  into  a 
few  longitudinal  folds.  The  tentacles 
proceed  from  the  anterior  sui'face  of  the 
body  and  penetrate  through  certain  fis- 
sures in  the  capsule  above,  diverging 
from  the  smface  in  a  radiating  manner. 
They  are  long,  capitate,  slightly  tapering 
and  retractile.  The  body  contains  a  cir- 
cular nucleus  and  a  contractile  vesicle. 
Maximum  dimensions  of  capsule  1-4'"  in 
height,  1-32'"  in  width.  The  minimum 
1-24"'  high,  and  1-43'"  wide. 

Stein  puts  this  Aci'neta  forward  as  one 
of  the  best  illustrations  to  be  obtained  of 
the  conversion  of  an  encysted  Vorticel- 
lina  into  an  Acineta.  The  Acineta  he 
identities  with  the  A.  7nystacina  (Ehr.), 
and  portrays  two  modes  of  develop- 
ment: one  by  a  series  of  ciliated  em- 
bryos, enveloped  each  in  its  own  capsule, 
given  off  from  the  surface  by  a  sort  of 
gemmation — this  process  going  on  until 
the  whole  animal  mass  is  exhausted; 
the  other  by  the  conversion  of  the  whole 
mass,  simultaneously,  into  several  elon- 
gated-oval gi'anular  germs,  covered  by 
a  membrane,  but  not  ciliated. 

Vorticella  microstoma. — Stein  consi- 
ders the  Actinophrys  Sol  and  Podophrya 
Jixa  (Ehr.)  to  be  the  Acinetiform  re- 
presentatives of  this  species  of  Vorti- 
cella.  In  our  opinion,  as  before  expressed, 
and  which  we  partake  in  common  with 
Cienkowski  and  others,  ■  the  being  de- 
scribed by  Stein  imder  the  name  Actino- 
phrys is  in  fact  an  Acineta.  It  is  repre- 
sented as  covered  by  a  firm  integument, 
which  frequently  assumes  the  characters 
of  a  cyst,  becomes  plicated  around  it, 
and  extended  into  a  hollow  pedicle, 
giving  it  the  appearance  of  Podoplwya. 
Moreover,  foreign  substances  were  never 
seen  to  enter  its  interior,  as  happens 
in  the  true  Actinophrys.  The  further 
history  of  this  Acineta  has  been  sketched 
in  the  chapter  on  development  of  CUiata 
(p.  360  et  seq.). 

V.  nehxdifera. — The  Acineta  in  Stein's 
estimation  belonging  to  this  species  of 
Vorticella  is  found  upon  Lemna.  The 
pedicle  is  much  longer  and  the  body 
more  contractile,  and  therefore  more 
changeable  in  figm-e,  than  the  Acineta 
found  on  the  Cyclops.  When  at  rest, 
their  figure  is  more  or  less  compressed, 
and  ovate  or  pear-shaped,  with  a  pro- 
minent angle  on  each  side  of  the  anterior 
margin,  from  which  a  bimdle  of  radi- 
ating retractile  tentacles  extends.  Oval, 
circular,  and  discoid  forms  are  not  mi- 
common.     The  stem  is  elastic,  curved, 


and,  as  a  rule,  lunger  than  the  body  it 
supports,  and  is  hollowed  by  a  narrow 
canal.  It  expands  at  its  junction  with 
the  body  and  then  spreads  over  it,  form- 
ing an  external  sheath  or  capsule,  except 
in  the  region  supporting  the  tentacles, 
where  it  seems  to  be  either  absent  or  of 
great  tenuity.  Beneath  this  is  a  special 
covering  of  the  Acineta  body,  entirely 
investing  it.  Notwithstanding  these  co- 
verings, the  body  is  remarkable  for  its 
contractility  and  the  mutability  of  its 
figure.  It  also  enjoys  a  certain  amoimt 
of  movement  on  its  pedicle,  bending  in 
this  and  that  direction  with  a  peculiar 
jerking  motion.  The  body  contains  an 
oval  nucleus,  and  from  one  to  three  con- 
tractile spaces.  It  developes  a  ciliated 
embryo.  The  length  of  the  body  is  from 
1-100'"  to  1-20'",  that  of  the  stem  not 
above  1-10'". 

Zoothamnium  affine,  —  The  supposed 
Acineta  of  this  animalcule  was  found  by 
Stein  on  marine  Cru-tacea — the  Qam- 
marus  marinas  and  Sph<reroma  serrata, 
along  with  the  Zoothamnium.  It  appea,rs 
identical  with  the  Acineta  tuberosa  (Ehr,). 
It  is  compressed,  campanulate,  or  p}T"i- 
form,  and  has  each  external  anterior 
angle  lobate  and  surmounted  by  a  group 
of  tapering  and  radiant  tentacula.  An 
intermediate  prominence  is  also  frequent, 
but  no  tentacles  spring  from  it.  The 
body  is  distinctly  enclosed  by  a  hyaline 
elastic  capsule,  which  is  extended  down- 
wards into  a  tubular  pedicle,  and  by  a 
softer  membrane  immediately  investing 
it.  The  latter  becomes  especially  pro- 
noimced  when,  as  fi-equently  happens,  it 
is  thrown  into  transverse  folds  in  its 
narrower  or  posterior  half  dming  the 
forcible  contractions  of  the  bodv. 


to  1-24'":  maximum 


more 

Length  fi'om  1-63' 

of  stem  1-18'". 

Carchesium  pyym<sum.  —  Stein  lat- 
terly referred  to  this  species  an  Acineta, 
common  on  Cyclops,  and  which  he  at 
first  assigned  to  Epistylis  diyitcdis.  The 
stem  is  very  short,  often  with  difficidty 
perceptible,  but  never  wanting.  The 
body  is  generally  pyriform  and  com- 
pressed; its  anterior  end  is  roimded  or 
truncate,  and  slightly  emarginate,  and 
supports  at  each  of  its  angles  a  bimdle 
of  tentacles.  Frequently  the  tentacula 
are  not  thus  gi'ouped  in  two  masses,  but 
occupy  the  whole  anterior  margin  and 
the  sides  for  a  short  distance — a  circum- 
stance met  with  in  smaller  specimens 
which  have  a  circular,  oval,  or  reniform 
figure.  The  nucleus  is  oval  and  small. 
No  movements  in  the  bodv  are  discerni- 


568 


SYSTEMATIC  HISTORY  OF  THE  INFUSOKIA. 


ble,  and  the  leugthening  and  sliortening 
of  the  tentacles  is  very  slow.  This 
Acineta  developes  a  ciliated  embryo 
which  resembles  the  Halteria  Grandi- 
nella  (Duj.).  Maximmn  length  1-30'". 
Common  size,  diameter  1-50'"  to  1-40'". 
Aci]\t:ta  diademifonnis  (xxin.  15-16). 
— Stein  describes  a  peculiar  Acineta 
foimd  upon  the  roots  of  Lemna,  under 
the  name  of  the  diadem-like  Acineta. 
Its  figure  is  compressed,  disciform, 
transversely  oval  or  reniform ;  and  it 
is  supported  on  its  somewhat  contracted 
base  by  a  short,  thick,  solid  stalk,  longi- 
tudinally striated,  and  often  marked  by 
a  few  transverse  lines.  The  stem  is 
always  so  short  that  the  body  looks  as 
if  sessile.  The  latter  is  enveloped  by 
a  thick,  structureless,  smooth  and  hya- 
line external  membrane,  and  by  a  second 
layer  beneath,  closely  investing  the  ani- 
mal mass.  On  the  free  margin  of  the 
body,  particularly  in  front,  a  number 
of  comparatively  thick  but  fine-pointed 
tentacles  are  disposed  at  slight  distances 
from  one  another.  These,  which  are  not 
clearly  capitate,  consist  of  a  delicate  mem- 
brane enclosing  a  finely  granular  matter, 
and  are  prolongations  from  the  special 
membrane  of  the  body;  consequently 
they  have  to  perforate  the  outer  enve- 
lope ;  and  Stein  leans  to  the  opinion  that 
the  latter  is  an  excretion  from  the 
former.  Usually  the  tentacular  pro- 
cesses are  very  slowly  retracted :  how- 
ever, when  the  Acineta  is  much  disturbed, 
the  shortening  takes  place  much  more 
rapidly,  and  renders  them  tortuous.  A 
long  band-like  nucleus  lies  across  the 
centre ;  and  a  number  of  transparent 
vesicles  are  disposed  at  equal  intervals 
around  the  border,  like  a  row  of  pearls 
around  a  diadem.  At  long  intervals  one 
or  another  of  these  sacs  is  seen  to  vanish. 


place,  like  true  contractile  vesicles.  No 
contractions  of  the  body  are  observable  ; 
it  remains  stiff  and  motionless.  It  pro- 
duces a  large  ciliated  embryo,  which 
lies  transversely  across  it  in  its  special 
sac.  Maximum  breadth  1-14'"  ;  height 
1-20'",  of  stem  1-100'". 

The  stiff  solid  stem  and  the  remarkable 
band-like  nucleus  indicate,  says  Stein, 
its  derivation  from  some  large  species 
of  Epistylis.  It  is  the  same  organism  as 
the  Acineta  Ferrum-eqiiinum,  according 
to  Lachmann. 

A.  digitata  (xxiii.  21). — Under  the 
name  of  the  fingered  or  digitate  Acineta, 
another  variety  of  this  class  is  charac- 
terized by  Stein,  who  failed  to  detect 
the  ciliated  Infusorium  to  which,  ac- 
cording to  his  h}^othesis,  it  shoidd  owe 
its  origin.  It  was  found  on  some  Ento- 
mostraca,  and  had  a  stemless,  patella- 
shaped  or  transversely  oval  body,  ad- 
herent either  by  the  whole  surface  in 
apposition  or  by  the  central  portion  only. 
Its  upper  side  usually  presented  irregular 
depressions  and  small  eminences,  and  was 
very  often  divided  into  an  anterior  and 
posterior  half  by  an  annular  constriction. 
From  the  entire  upper  surface,  or  only 
from  its  anterior  section  when  the  central 
constriction  is  present,  a  number  of  di- 
vergent, very  thick,  finger-like  tentacles 
spring,  apparently  without  order  and 
non-retractile.  No  contractions  of  the 
body  were  ^\dtnessed ;  but  some  change 
of  outline  is  possible.  A  narrow,  coiled 
nucleus  is  brought  into  view  by  acetic 
acid.  The  peculiar  contractile  vesicles 
are  wanting ;  but  from  two  to  three  im- 
changeable  clear  spaces  of  dilFereut  sizes 
exist.  Along  with  these  normal  speci- 
mens, others  occurred  ha^dng  a  smooth 
surface  and  no  processes.  Maximmn 
width  1-30'":  heig-ht  1-58'". 


and  after  a  time  to  reappear  in  the  same  j 

Genus  OPHRYODENDRON.  —  Noticed  and  named  in  Lachmann  and 
Claparede's  paper  in  the  Ann.  d.  Sc.  Nat.  1857.     No  description  given. 

It  is  said  to  be  a  very  singular  animal,  doubtfully  referable  to  Acinetina, 
found  parasitic  on  Campanularia  from  the  Norwegian  coast.  One  species  is 
named. 

OPHRYODENDnoN  ahietinum. — Characters  imdescribed. 


GROUP  III.— CILIATA  (p.  199  and  p.  266). 

The  group  of  the  ciliated  Protozoa,  according  to   the  scheme  adopted,  are 
resolved  into  two   di\-isionR  :  —  1,  mouthless  (Astoma) ;  and  2,  those  hanng 


OF  THE  CILIATA. ASTOMA.  569 

a  mouth  (Stomatoda).  Of  the  former  we  have  in  the  general  history  de- 
scribed two  familes,  viz.  Opaliniea  and  Peridinisea  ;  and  we  shall  first  pro- 
ceed to  give  a  systematic  account  of  their  several  recognized  members,  and 
in  so  doing  recHstribnte  certain  species  and  genera  other^^se  classed  by 
Ehrenberg, — for  instance,  several  Opalince  described  among  the  Bursaries. 
Again,  in  the  systems  of  Dujardin  and  Perty,  several  mouthless  genera  are 
enumerated  which  must  find  their  place  in  the  fii'st  division  of  the  Ciliata,  as 
adopted  by  us.  Such  are  the  Leucophryina  of  Dujardin  generally,  together 
with  a  few  Ploesconiens  and  Ervihens,  and  the  Cobalina  of  Perty.  The 
Peridiniaea  of  Ehrenberg,  again,  include  two  genera,  Choitotyphla  and  Ghce- 
toglena,  which  should  rightly  find  a  place  among  Phytozoa  ;  but,  to  avoid 
disturbing  the  classification  employed,  we  have  retained  them  in  the  same 
family. 

Among  the  Stomatoda  are  described,  not  only  the  families  eniunerated  by 
Ehrenberg  (see  p.  377),  but  also  those  constitiited  by  Perty,  Dujardin,  and 
others, — the  place  of  their  introduction  being  determined  by  the  Ehrenbergian 
group  to  which  they  appear  to  hold  the  greatest  afiinity. 

We  commence  the  systematic  account  of  the  Stomatoda  \sith  the  ill- defined 
and  imperfectly  obsen'ed  family  Cyclidina,  and  take  the  other  Ehrenbergian 
families  in  the  order  sho^^^l  at  p.  377.  With  the  Yorticellina  the  Urceolarina 
of  Dujardin  and  the  Yagiuifera  of  Perty  are  conjoined,  as  well  as  several 
genera  newly  instituted.  The  Ophiydina  embrace  additional  genera ;  and  the 
genus  Enclielia,  wliilst  it  is,  on  the  one  hand,  dej)rived  of  the  xer^'  heterogeneous 
organisms  introduced  into  it  by  Ehrenberg,  viz.  Actinoplirys,  Acineta,  and  Tri- 
chodiscus,  and  which  have  ali^eady  been  treated  as  subfamilies  of  Pthizopoda, 
it  has,  on  the  other,  appended  to  it  the  families  Tapinia,  Apionidina,  and 
Holophryina  of  Perty,  besides  several  genera  named  by  this  naturalist  and 
by  Dujardin.  The  history  of  Bursarina,  Decteria,  and  Cinetochilina  (Perty), 
is  included  in  that  of  the  Trachelina ;  and  that  of  Paramecina  (Duj.)  and 
Aphthonia  (Perty)  in  the  account  of  Kolpodea.  The  Ox5i;richina  embrace 
the  Keronina  (Keroniens)  of  Dujardin  ;  lastly,  the  Euplotina  comprehend  the 
Ploesconiens  and  Erviliens  of  the  same  writer. 

Division  A.— ASTOMA. 
FAMILY  I.— OPALIN^A.    (Part  I.  p.  267.) 
(XXII.  46,  47 ;  XXYI.  28,  29.) 
Ciliated  parasitic  Protozoa,  consisting  of  a  more  or  less  oval  sac,  which  resem- 
ble in  figure  many  Bursance,  and,  although  often  presenting  an  anterior  fold 
or  fossa,  have  no  mouth.    They  contain,  besides  the  usual  molecular  matters, 
a  granular  nucleus,  and  multiply  by  transverse  fission.     A  globular  contractile 
vesicle  is  absent  in  all ;  but  in  0.  Planariarinn  and  0.  uncinata  (of  Schultze) 
an  elongated  pulsating  sac  occims,  recalling  in  character  the  so-called  dorsal 
vessel  of  various  higher  animals ;  and  in  others,  instead  of  a  contractile  vesicle, 
numerous  irregularly -disposed  saccular  spaces  occur.     The  nucleus  is  not  dis- 
coverable in  0.  Ranarum,  whilst  in  0.  hranchiarum  one  of  unusually  large 
volume  is  found.     Oj^alinoi  are  probably  larvae  of  various  vermes,  and  not 
independent  organisms. 

Genus  OPALINA. — The  characters  the  same  as  those  of  the  subclass.  It 
^\ill  be  seen,  in  the  following  specific  descriptions,  that  many  of  the  Oixdince 
have  been  described  by  other  systematic  writers  as  members  of  genera  of 
Stomatoda,  such  as  Bursan'a,  Leucoplirys,  and  Paramecli(m.  Stein  has  de- 
voted much  attention  to  the  Opalincv  ;  and  we  accept  his  determination  of  the 


o/ 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


characters  and  distinctions  of  species,  along  Ts^th  the  names  he  has  assigned 
them. 

The  genus  Opalina  was  constituted  by  Pm^kinje,  and  has  been  generally 
accepted.  Dujardin  introduced  0])alinci  into  his  family  Leucophryina  along 
with  Leucoplvnjs  and  Spathidium,  and  characterized  that  family  as  of  a  com- 
pressed-oval or  oblong  figure,  clothed  with  closely-arranged  ciHa  in  regular 
series,  and  apparently  destitute  of  a  mouth. 


Opalina  Ranarum  =  Bursaria  Rana- 
rmn  (E.). — The  mouth  described  by 
Elirenberg  in  this  species  is  merely  a  fold 
of  the  sm-face,  as  may  be  proved  by  add- 
ing a  dilute  solution  of  iodine,  of  alcohol, 
or  of  acetic  acid,  which  will  cause  the 
animal  to  swell  up  aud  evenly  distend 
the  entire  surface.  Stein  could  find  no 
nucleus.  This  species  is  common  in  the 
intestine  and  bladder  of  frogs.  Perty 
makes  it  to  include  besides  Bursaria 
Ranarum  (E.),  also  B.  Entozoon,  B. 
Nucleus,  and  probably  B.  intestinalis. 

O.  Planariarum  (Siebold)  =  O.  poly- 
morpha  (SchiQtze).  —  The  body  has  the 
form  of  a  long  cylindrical  sac,  pointed  and 
wedge-shaped  posteriorly,  and  expanded 
iu  front  as  a  remarkable  semicircular 
disc,  by  the  central  part  of  which  it  ad- 
heres to  the  surface  of  the  intestine  it 
occupies,  the  border  being  crowmed  with 
a  wreath  of  long  cilia.  The  actual  point 
of  attachment  appears  destitute  of  cilia ; 
but  the  posterior  sm-face  is  thickly  studded 
with  shorter  ones.  The  contents  consist 
of  a  homogeneous  molecidar  substance, 
with  numerous  interspersed  hyaline 
spaces.  A  long  pulsating  vesicle  (or, 
from  its  length,  a  vessel)  and  a  nucleus 
are  also  seen  ^vithin  the  interior.  The 
pulsating  vessel  extends  to  the  extreme 
point  of  the  body  behind,  just  beneath 
the  integment,  but  not  in  union  with  it, 
aud  terminates  on  the  anterior  side  of 
the  semicircular  process  in  front.  Its 
walls  are  structureless  and  transparent; 
aud  by  its  alternate  contractions  and  ex- 
pansions it  pushes  forth  the  contained 
water  alternately  from  each  end.  The 
position  of  the  nucleus  in  the  interior  is 
not  constant ;  it  consists  of  a  finely 
granular  mass  containing  some  larger 
granules,  and  is  sharply  defined.  Fission 
is  transverse,  the  nucleus  and  contractile 
vessel  dividing  consentaneously  Muth  the 
body.  Stein  could  not  discover  the 
orifices  at  the  end  of  the  pulsating  vessel 
described  by  Schidtze.  Maximum  size 
1-3'"  in  length ;  breadth  1-20'"  ;  length 
of  nucleus  1-25"'. 

0.  Lumhrici  (Stein). — Is  represented 
bv  Leucophrys  striata  and  L.  nodulata 
(l)uj.),  the  latter  being  an  altered  form 


of  the  former,  dependent  on  iiTegular 
endosmosis  of  the  water  in  which  it  is 
placed.  Transverse  fission  occurs  in  aU 
sizes,  which  vary  from  1-60"'  to  1-14'". 
Parasitic  in  earth-worms  (Ltmibrim). 

0.  armata  (Stein)  =  O.  Lumhrici 
(Duj.). — Has  an  oval  compressed  figm-e 
like  the  foregoing,  from  which  it  differs 
by  ha\ung  a  strong,  horny,  micinate  pro- 
cess at  the  anterior  extremity,  on  the 
under  surface  of  the  body,  and,  extending 
fi-om  it,  a  fold  of  the  sm-face.  The  other- 
Tvdse  homogeneous  and  finely  granular 
nucleus  is  remarkable  by  exhibiting  a 
greater  or  less  number  of  solid  oval 
nuclei  and  elongated  rods.  Specimens 
of  this  species  are  peculiar  by  their  uni- 
formity of  size,  which  somewhat  exceeds 
that  of  the  largest  O.  Luinhrici,  being 
from  1-12"'  to  1-8'"  :  hence  Stein  pre- 
sumes that  O.  armata  is  nothing  more 
than  a  fm-ther  developed  phase  of  0. 
Lumhricij  from  which  it  diners  only  in 
size  and  in  the  presence  of  the  prehensile 
apparatus.  He  surmises  fm*ther  that 
this  and  other  OpaUncB  may  be  members 
in  the  chain  of  development  of  worms. 

0.  A))odontce  (Stein)  =  Leucophrys 
Anodontce(E.). — Mouthless,  oval,  turgid, 
transparent ;  ciliated  equally  throughout. 
1-36'".  Parasitic  in  Anodofita  and  3fy- 
tilus  edulis. 

0.  branchiaru?n. — Is  characterized  by 
its  very  lar^e  nucleus,  which  equals  in 
volume  the  half  of  the  entire  organism. 
Its  contom*  is  also  similar ;  and  it  might 
be  taken  for  an  imprisoned  animal. 
Common  in  the  ovisacs  of  Gammarus 
Pulex. 

O.  lineata  (Schultze).  —  Is  without 
uncini,  and  has,  like  the  last,  a  very  large 
nucleus.  In  Nais  liitoraUs  (see  Schultze's 
work  Beitrciye  zur  Naturgeschichte  der 
Turhellarien,  Clreifswald,  1851,  p.  69). 

O.  Ndidos  (Duj.)  (XXVI.  28,  29).— Is, 
like  the  preceding,  unfui-uished  with  a 
prehensile  apparatus.  Figm-e  oval,  or 
very  elongated  and  nearly  cylindrical, 
longitudinally  and  transversely  striated : 
the  fold  extends  from  the  anterior  ex- 
tremity nearly  to  the  middle.  Numerous 
clear  spaces  in  the  interior,  irregularly 
distributed.     1-22'"  to  1-11'".    Parasitic 


OF  THE  CILIATA. STOMATODA.  571 

in  Na'is  (one  of  the  Annelida)  (xxi.  28,  !  supposes  this  armature  replaces  the  usual 
29).  i  fringe  of  cilia,  in  the  animals  after  having 

0.  uncinata  (Schultze).  —  "Resembles  :  attained  a  certain  age  or  stage.  In  the 
0.  Planariarum  in  general  organization  ;  interior  of  Plcmaria  Ulva,  &c.  1-120". 
it  has  the  same  soi-t  of  pulsating  vessel,  O.  Tritonis  (Pertj^). — Discoid,  rounded 
and  a  similar  nucleus ;  it  multiplies  by  in  front,  wdth  a  loop-like  depression ; 
transverse  fission,  and  differs  from  all  colourless.  1-336".  Revolves  on  its 
other  known  Opalince  by  having  a  pair  shorter  axis.  Parasitic  in  the  intestine 
of  strong,  homy  uncini  at  the  anterior  of  Triton  cnstafus  (the  crested  Water- 
extremity,  one  on  each  side  of  the  median  newt).  Is  very  like  O.  Hananmi,  and 
line,  giving  it  a  bilateral  character.  Stein    requires  fmther  examination. 

O.  Nucleus  =  Bursaria  Nucleus ;  0.  Entozoon  =  Bursaria  Entozoon ;  O.  intestinalis 
=  Bursaria  intestinalis.  These  three  presumed  species  are  nothing  more  than 
different  phases  of  gi'owth  and  development  of  Opafina  {Bursaria,  Ehr.)  Ranarum. 
We  have,  however,  retained  the  brief  notes  of  their  characters  as  Bursarice  given 
by  Ehrenberg. 

FAMILY  IT.— COBALINA  (Perty). 

Animals  parasitic  ;  either  mth  or  without  a  mouth  ;  most  of  them  receive 
only  the  juices  of  other  animals.  Body  mostly  flattened,  oval,  elliptic,  or 
remfoiTQ,  T\-ith  numerous  rows  of  very  delicate  cilia,  and  often  with  an  un- 
cinate vaiiety  on  the  under  surface.  An  oral-looking  depression  or  fold  fur- 
nished with  stronger  cilia  commonly  perceptible  ;  but  several  have  no  such 
indication  of  a  mouth.  Only  those  living  externally  upon  animals  are  capable 
of  receiving  solid  noimshment.  In  internal  functions  and  in  foiTQ  they  pre- 
sent a  general  uniformity  and  agreement,  and  are  equally  peculiar ;  they 
occupy  a  lower  position  than  free  living  forms  similar  to  them  ;  their  move- 
ments are  simply  automatic  in  character. 

a.   With  rows  of  cilia  above,  and  uncini  beneath. 

Genus  ALASTOE. — The  type  of  this  genus  is  the  Kerona  Polyporum 
(Ehr.),  and  is  called  Alastor  Polyporimi. 

b.   With  delicate  cilia  both  above  and  beneath.     Receive  only  the  juices  of 

other  animals. 
Genus  PLAGIOTOMA(Duj.)  (vide  Family  TuACHELmA). 
Plagiotoma  Lumbrici ;  Pl.  Concharurn ;  Pl.  (?)  diffoi'mis. 

Genus  LEUCOPHRYS  (Duj.)  {vide  ante,  p.  570,  Opaloa  Lumbrici). 
Leucophhys  striata. 

Division  B.— STOMATODA. 

FAMILY  I.— CYCLIDIXA. 
(X.  209-212). 

Illoricated  Polygastriea  devoid  of  eye-specks  and  of  true  alimentary  canal, 
and  having  but  one  alimentary  aperture,  fui-nished  \\ith  cilia  or  bristles,  the 
various  groupings  and  relations  of  which  afford  characters  for  the  discrimina- 
tion of  the  genera ;  gastric  cells  (vacuoles)  have  been  observed  in  two  species 
of  Cyclidium.  Locomotion  is  effected  by  the  \ibratile  cilia  and  a  filament 
proceeding  from  the  anterior  extremity. 

The  genera  are  distributed  as  follows : — 

[  Body  compressed — cilia  arranged  in  a  single  |  ^    y-,- 
Body  furnished  with  ciHa  ]      circle j     " 

1  Body  round—  cilia  scattered  all  over Pantotrichum. 

Body  furnished  with  bristles Cha?tomonas. 


572  SYSTEMATIC  HISTOKY  OF  THE  INFUSORIA. 

This  family  has  no  corresponding  one  in  the  system  of  Dujardin.  Some  of 
its  members  are  represented  in  the  family  of  the  Enchelina  as  members  of  the 
genera  Acomia  and  EncJielijs.  The  genus  Cijclidium  (Duj.)  is  included  among 
the  Monadina  of  that  author  (p.  497),  and  includes  beings  fui^nished  with  a 
filament,  but  destitute  of  mouth  and  cilia — characters  not  at  all  analogous  to 
those  given  by  Ehrenberg  to  his  genus  of  this  name. 

Perty,  moreover,  has  not  retained  this  family  in  his  system,  although  he 
accepts  the  genus  Cyclidium,  which  he  refers  to  a  family  called  "■  Tapinia," 
where  it  is  associated  with  Acomia  (Buj.),  with  Leucoplirys  (Ehr.)  or  Tnchoda 
(Duj.),  and  with  the  follo^ving  newly-instituted  genera:  viz.  AcropistMum, 
Bceonidiumy  Opistliiotricha,  Siagontherium,  and  Mecjatricha, — a  set  of  terms  not 
recommending  themselves  bj'-^  their  euphony,  and,  we  presume,  not  wanted  in 
a  true  systematic  distribution  to  express  distinct  and  independent  forms  of 
ciliated  Protozoa.  However,  to  render  our  7'esume  complete,  these  presumed 
new  genera  are  appended  to  the  family  of  Enchelia,  to  which  several  of  their 
species  are  referred  by  Ehrenberg. 

The  family  Cyclidina  (Ehi\)  would,  in  all  probability,  disappear  from  a 
revised  system  of  classification.  Thus  Cyclidium  appears  to  be  only  an  em- 
biyonic  phase  of  other  animalcules,  and  Pantotrichum  and  Chcetomonas  are 
not  sufficiently  characterized  and  examined  by  Ehrenberg  to  enable  us  with 
certainty  to  recognize  them,  or  to  determine  their  affinity.  Moreover,  the 
beings  brought  together  under  these  genera  are,  some  of  them  at  least,  very 
doubtfully  referable  to  them,  and  have  been  so  casually  examined  that  their 
identification  would  be  difficult.  The  ova  and  the  polygastric  organization 
mentioned  in  Ehrenberg's  account  are  matters  only  of  hypothesis. 

Genus  CYCLIDIUM. — Body  compressed  discoid,  provided  with  a  simple 
circular  row  of  cilia.  In  G.  Glaucoma  alimentary  vacuoles  are  distinct.  The 
mouth  is  a  rounded  opening,  situated  upon  the  under  surface  of  the  body, 
either  close  at  the  anterior  extremity,  or  towards  the  centre.  The  organs  of 
locomotion  consist,  as  in  Kerona  and  StylonycMa,  of  a  number  of  cilia-like 
feet,  situated  on  the  margin  of  the  abdomen.  It  has  been  thought  that 
longitudinal  lines,  produced  by  rows  of  very  delicate  cilia,  were  present ;  if 
so,  and  an  anal  opening  be  discovered,  C.  Glaucoma  would  rank  with  the 
Oxytrichina.  Fission  transverse.  Since  Ehrenberg  wrote  these  observations, 
Lachmann  has  described  not  only  a  mouth,  but  also  an  anus  on  the  ventral 
siu'face  near  the  posterior  extremity.  This  statement,  taken  in  connexion 
with  another,  that  some  at  least  of  the  forms  of  Cyclidium  are  embryonic 
stages  of  other  animalcules,  leaves  this  genus  in  the  greatest  uncertainty  both 
as  to  its  independent  existence  and  its  systematic  position. 

Cyclidium  Glaiwoma  (M.). — Oblong- 
elliptic,  abdomen  fringed  with  cilia  ; 
delicate  longitudinal  strise  are  observed 
upon  the  back.  In  swimming,  it  re- 
sembles Gyrinns,  or  Notonecta,  a  well- 
known  little  black  water-beetle  (see 
3Iicroscopic  Cabinet,  pi.  4).  Sometimes 
the  movement  is  very  quick ;  at  other 
times  the  animalcules  remain  for  a  while 
stationai-y,  and  then  presently  spring 
vdih.  a  curvetting  motion  to  another 
vspot.  Fonnerly  this  species  was  con- 
founded with  Glaucoma  scintillans,  but 
is  much  smaller  (x.  209  is  a  side  view, 
showing  the  cilia ;  fig.  211  a  dorsal  view : 
and  fig.  210  a  specimen  undergoing  trans- 


verse self-division).  They  are  repre- 
sented as  fed  with  indigo.  Abundant 
in  vegetable  infusions  in  the  spring. 
1-2880"  to  1-1150". 

Betwixt  this  species  and  Enchelys 
nodulosa  (Duj.)  there  is  a  complete 
agreement.  The  body,  on  a  transverse 
section,  is  triangular ;  hence  it  is  (says 
Perty)  that  Dujardin  has  described  it  as 
sometimes  assuming  a  triangvdar  form. 
Chlorophyll  granides  are  occasionally 
seen  interaally.  Stein  identifies  the 
embryo  of  Chilodon  Cuculhdus  with  this 
species  of  Cyclidium,  which  he  would 
tliereforc  exclude  from  the  category  of 
independent  animalcules.  Internally;this 


or  THE  CTCLIDINA. 


•3 


excellent  observer  also  describes  a  con- 
tractile vesicle  and  a  discoid  nucleus ; 
the  foiTuer  is  the  clear  space  mistaken 
bv  Ehrenberg  for  a  mouth.  At  the  same 
time  he  considers  an  oral  aperture  most 
probably  exists  somewhere  near  the 
middle  of  the  organism,  since  he  has 
seen  the  entrance  of  solid  particles  into 
the  interior.  Perty  makes  C.  Glaucoma 
svnon}Tnous  also  with  Enchcdys  tri(p(etra 
(Ehr.),  and  probably  with  the  Para- 
mecium Milium  and  Cycliclium  3Iillum  of 
Miiller.  In  his  system  it  is  a  member  of 
the  family  Tapinia,  where  it  is  conjoined 
with  some  species  of  Leucojjhrt/s,  with 
Acomia  (Duj.),  and  several  newly- 
cveated  genera. 

C.  marijaritaceum. — Orbicular,  ellip- 
tical ;  the  posterior  end  slightly  excised  ; 
the  dorsal  surface  with  distinct  longi- 
tudinal lines  ;  cilia  not  distinct.  1-1500" 
to  1-1000". 

This  species  is  separated  by  Perty  from 
Glaucoma,  and  constitutes  in  his  system 
the  representative  of  a  genus  he  names 
Cinetochilum,  which,  vnth.  Glaucoma, 
fonns    the    family    Cinetochilina    {vide 

Genus  PANTOTRICHUM. 


Glaucoma).  The  Cin.  marcjaritaceum  is 
characterized  as  a  sliort  elliptical  animal, 
rather  compressed  and  with  its  vibratile 
flap  on  the  posterior  half,  colourless  and 
transparent.  Movements  quick;  rota- 
tion on  its  axis  rare.  Cilia  very  short. 
Fission  transverse.  1-810"  to  1-720". 
Lachmann  {A.  N.  H.  xix.  216)  appears 
to  approve  of  the  systematic  position 
assigned  by  Perty  to  this  being. 

C.  (P)  planum.  —  Oblong-elliptic, 
smooth  ;  cilia  but  little  marked.  l-2tJ40". 

C.  (?)  lentiforme.  —  Smaller  than  C. 
planum,  and  has  no  distinct  strice  or  cilia, 
1-3180". 

C.  Arhorum.  —  Small,  suborbicular, 
slightly  excised  laterally;  dorsum  ru- 
gose ;  margin  ever^-where  ciliated.  Diam. 
1-192"'.  Marginal  cilia  used  in  the  way 
of  feet ;  swims  rapidly.  Fission  trans- 
verse.    On  moss  of  trees. 

This  animalcule  is  identified  by  Cohn 
(Siebold's  Zeitsch.  1851,  p.  273)  \\ath  the 
embryo  developed  by  Loxodes  (Parame- 
cium) Bursaria.  If  this  be  the  case,  it 
must  be  rejected  from  the  list  of  inde- 
pendent species. 

Body  turgid,  covered  with  moveable  cilia.    In 


P.  Enclielys  gastric  cells  (vacuoles)  are  distinctly  visible.  Granules,  green  or 
yellow,  occupy  the  interior.  Ehrenberg  says,  "  The  absence  of  a  double  ah- 
mentary  aperture  is  not  yet  proved;  nor,  on  the  other  hand,  is  its  existence." 
Pantotiichum  is  not  received  by  Perty  as  an  independent  genus,  but  is  com- 
prehended by  him  with  Lagenella  and  Chcetoglena,  under  the  common  appel- 
lation Clionemonas,  and  placed  among  the  Thecamonadina. 
Pantotrichum  Enchelys. — Cylindri-  ;  Ovate,  spherical,  of  a  green  coloiu:.     In 


cal,  oblong,  roimded  at  both  ends ;  hya- 
line at  extremities  and  turbid,  the  centre- 
colour  pale  yellow,  x.  212  is  a  cluster 
of  animalcules ;  those  to  the  left  are 
more  highly  magnified  than  the  others. 
In  swimming  they  revolve  and  glide 
along  in  the  direction  of  the  longer  axis 
of  the  body.  In  infiLsions  of  raw  flesh. 
1-1150'. 
P.  vulvox  {Zicucoplirya  viridis,  M.). — 


brackish  water.     1-860' 

P.  Lagenella. — Ovate,  the  ends  equally 
rounded,  anterior  ciliated  portion  pro- 
duced in  the  form  of  a  neck  or  beak. 
Amongst  Conferv?e.    1-1080"  to  1-570". 

Schneider  {A.  N.  H.  1854,  p.  329)  de- 
scribes this  species  as  forming  around 
itself  a  cyst,  which  completely  retains 
the  flask-like  form  of  the  body,  when  the 
animalcule  enters  on  a  state  of  rest. 


Genus  CH^TOMOXAS. — Motion  slow,  and  leaping  by  means  of  the  bristles 
on  the  body,  which  are  not  vibratile.  Internal  organization  very  little  known. 
They  are  parasites,  living  on  the  dead  bodies  of  other  Infusoria,  and  in  infu- 
sions of  flesh  or  other  animal  matters.  A  vibration  is  seen  at  the  mouth  ;  but 
whether  it  is  produced  by  a  filament  or  by  cilia,  is  uncertain.  In  C.  con- 
stricta,  transverse  self-division  is  thought  to  have  been  seen. 


Ch^^tomonas  Glohdus.  —  Almost 
spherical,  of  an  ash-colour,  furnished 
with  setse  or  bristles.  It  often  has  the 
figure  of  Monas  Guttula,  but  is  larger; 
sometimes  two  cluster  too-ether.  In 
bad-smelling  infusions  of  animal  matter 
along  with  Pantotrichum  Enrhelys,  Monas 


Termo,  &c. ;  also  in  the  dead  fi-onds  of 
Closterium  acerosum,  as  shown  at  x.  113. 
1-2880". 

C.  constricta.  —  Transparent,  oblong, 
slightly  constricted  at  the  middle,  and 
ha^nng  two  set.ie  or  bristles.  In  dead 
Hydatina  senfa.      1-5760". 


574  SYSTEMATIC  IIISTOEY  OF  THE  INFUSOEIA. 

FAMILY  II.— PEEIDINIJEA.    (Part  I.  p.  271.) 
(PL  X.  214-226  ;  XII.  47  ;  XXXI.  16-23.) 

Infusoria  without  an  alimentary  canal,  covered  with  a  lorica,  upon  which  cilia 
or  setae  are  often  arranged  in  the  form  of  a  zone  or  crown — hence  the  name. 
The  lorica  has  only  one  opening.  Three  out  of  the  four  genera  have  a  fila- 
ment besides  the  wreath  of  ciHa  around  the  middle  of  the  body,  or  scattered 
cilia  or  bristles.  In  only  Peridinium  Pulvisculus  and  P.  cinctum  have  artificial 
means  succeeded  in  demonstrating  the  admission  of  food,  the  internal  organi- 
zation being  greatly  obscui^ed  by  the  mass  of  coloiured  opake  granules,  which 
Ehrenberg  called  ova.  A  nucleus  and  a  red  stigma  (eye,  Ehr.)  are  discover- 
able in  some  species. 

The  genera  are  disposed  as  follows : — 

Lorica  having  stiff  bristles  or  short  spines — no  transverse  J  ^     ^" 

fiuTOwed  zone |  eye  present  Chsetoglena. 

T     .  ^,  ,  -1  •  ^   1  ^  f  no  eye  Peridinium. 

Lorica  smooth  or  rougli — a  ciliated  transverse  zone  pre-  '  "^ 


^®^*' • I  eye  present Glenodinium. 

Some  of  the  presumed  species  have  been  found  only  in  a  fossil  state  in  flint. 

Dujardin  constitutes  a  family  Peridiniens,  agreeing  in  the  main  with  that 
of  Ehrenberg,  and  thus  narrates  its  characters:  '' Animals  without  known 
internal  organs ;  enveloped  in  a  regular,  resistant,  membranous  lorica,  which 
sends  off  a  long  flageUiform  filament,  and,  in  addition,  has  one  or  more  furrows 
beset  with  vibratile  cilia." 

The  lorica  would  appear  to  have  no  opening  ;  for  foreign  bodies  and  colour- 
ing matter  are  not  seen  to  enter  it.  Several  have  theii^  lorica  prolonged  into 
horn-like  processes ;  and  some  exhibit  a  coloured  point  (eye-speck).  They 
are  distinguished  from  Thecamonadina  by  the  ciliated  furrow  or  fuiTOWS. 

Dujardin  observes  that  "  as  the  first  two  of  Ehrenberg's  genera  are  with- 
out the  furrow  and  vibratile  ciha,  and  have  only  a  filament  as  a  locomotive 
organ,  they  are  evidently  akin  to,  and  not  separable  from  the  Thecamonadina, 
unless  spines  or  asperities  of  the  lorica  are  to  be  taken  for  cilia.  Again,  the 
so-caUed  eye-speck  is  not  a  sufficient  generic  distinction  between  Peridinium 
and  Glenodinium  ;  the  former  genus,  moreover,  should  only  include  spherical 
animalcules,  whilst  those  concave  on  one  side,  and  exhibiting  horns,  will 
rightly  form  a  distinct  genus — Ceratium.^^ 

Perty  coincides  with  Dujardin  in  detaching  Chcetotyphla  and  Chcetoglena 
from  the  Peridinigea,  and  in  uniting  them  with  Thecamonadina.  OhcetogJena 
he  merges  with  Pantotrichum  and  LageneUa  in  a  genus  which  he  names  Chone- 
monas  (p.  513).  His  Peridiniaea  comprehend  three  genera,  viz.  Ceratiwn, 
Glenodinium,  and  Peridi^iium:  the  first  characterized  by  a  cellular  lorica 
prolonged  into  horns ;  the  second  by  a  ceUular  not-horned  lorica ;  and  the 
third  by  a  structm-eless  lorica.  A  reference  to  the  figures  of  Chcetoglena  and 
Chcetotyphla  is  sufficient  to  show  that  these  two  genera  have  no  claim  to  be 
ranged  with  Peridiyiium :  the  former,  in  particular,  indicates  in  its  structure 
and  general  appearance  a  member  of  the  Cryptomonadina ;  and  the  latter,  if 
not  a  member  of  the  same  order,  is  certainly  not  one  of  the  Peridiniaea,  but 
probably  the  encysted  state  of  some  animalcule.  The  imperfect  descriptions 
attached  to  these  genera,  and  the  absence  of  sufficiently  distinctive  features 
in  their  illustrations,  renders  their  exact  identification  with  similar  known 
forms  a  matter  of  difficulty,  if  not  of  impossibility.     Again,  the  special  differ- 


OF  THE  PEilIDINI3:A.  575 

ential  character  between  Glenodinium  and  Peridinium,  yiz.  the  existence  of  a 
red  speck  in  the  former,  is  worthless  ;  and  were  no  other  peculiarities  discover- 
able, the  two  genera  should  be  merged  into  one.  However,  the  elongation  of 
the  lorica  into  horn-like  processes  supplies  a  differential  character  sufficient 
at  least  to  constitute  two  genera  out  of  their  several  members.  Ehrenberg  re- 
cognized this  inchcation  of  a  division,  and  adopted  it  for  his  eyeless  Peridiniaea, 
making  two  sections  : — 1,  Peridinium  proper ;  and  2,  Ceratimn,  horned  Peri- 
dinia,  Perty,  we  have  seen,  uses  the  same  structural  peculiarity  as  a  generic 
character,  but,  in  addition,  makes  a  third  genus,  marked  by  the  absence  of 
sculpturing  on  its  lorica.  This  basis  we  hold  to  be  insufficient  for  a  generic 
distinction ;  and  the  whole  of  the  Peridiniasa  proper  appear  to  us  reducible  to 
the  two  genera  Peridinium  and  Ceratium;  Glenodiniion  we  would  conse- 
quently cancel.  The  rejection  of  Ehrenberg's  views  of  internal  organization, 
and  of  two  of  the  four  genera  he  classed  as  Peridiniaea,  renders  a  revised 
description  of  this  family  necessary.  In  attempting  this,  we  may  state  that 
the  Peridiniaea  are  animalcules  having  an  external,  condensed,  chitinous  inte- 
gument forming  a  lorica,  lined  by  a  contractile  membrane  immediately  invest- 
ing the  organic  contents.  'No  actual  oral  opening  is  satisfactorily  made  out ; 
but  in  most  species  a  deep  fossa  or  fissure  is  found,  from  the  bottom  of  which 
a  flabehum  extends,  mostly  twice  or  more  than  twice  the  length  of  the  body. 
Their  figure  is  more  or  less  globular  or  ovate ;  and  sometimes  the  lorica  is  ex- 
tended into  two  or  three  long  horn-like  processes,  giving  the  whole  being  a 
very  bizarre  appearance.  A  deep  fiuTow  surrounds  the  body  as  a  zone,  and  in 
some  species  a  vertical  prolongation  of  it  extends  to  one  pole.  These  furrows 
are  richly  ciliated ;  yet  the  cilia  do  not  appear  confined  to  them,  as  Ehrenberg 
supposed,  but  may,  at  least  in  one  species,  cover  the  entii^e  sm-face.  The 
interior  is  occupied  by  masses  of  usually  strongly-coloured  brownish  yellow,  or 
reddish  or  greenish  brown,  rendering  the  animalcules  very  opake.  In  some 
species  an  oval  nucleus  has  been  seen  ;  and  its  presence  is  presumable  in  all. 
A  contractile  vesicle  has  not  yet  been  demonstrated.  They  multiply  by 
transverse,  and  it  may  be  also  by  longitudinal  fission.  P.  uberrimum  has  been 
found  in  a  quiescent  condition ;  and  doubtless  some  mode  of  propagation  exists ; 
Perty  endeavours  to  prove  it  is  by  internal  germs.  The  zone-like  ciliary 
furrow  may  be  adduced  as  the  leading  characteristic. 

Genus  CILETOTYPHLA. — Lorica  silicious,  hispid  or  spinous,  destitute  of 
a  transverse  fiuTow  or  zone,  and  of  stigma ;  surface  covered  with  little  spines 
and  bristles,  which  appear  stronger  at  the  posterior  portion  of  the  body.  The 
lorica  may  be  crushed  by  pressure,  and  the  httle  creatiu-e  within  it  be  set  at 
liberty.  In  swimming  it  revolves  upon  the  longitudiaal  axis,  probably  by 
means  of  a  delicate  filiform  proboscis,  or  of  cilia  at  its  mouth ;  no  such  organs, 
however,  have  been  seen.  Of  the  internal  organization,  nothing  positive  is 
known.  One  species  has  been  discovered  in  flint,  and  so  closely  resembles 
Xanthidium,  that  it  is  often  mistaken  for  it. 

CiL^TOTYPHLA  cirmcita. — Ellipsoidal,  |  C.  aspera. — Brown,  oblong,  rounded  at 
browTi,  ends  rounded ;  covered  posteri-  |  both  ends,  and  rough,  with  short  bristles ; 
orly  with  short  spines,  where  there  is  a  I  the  little  spines  are  scattered  without 
circlet  of  black  spots,  as  sho^na  in  the  i  order  at  the  posterior  end.  Fomid  with 
end  view,  x.  215.  The  anterior  ciHa,  or  |  the  preceding.  1-570". 
fine  bristles,  are  sometimes  very  indi-  I  C.  (?)  Pyritce. — Oblong  cylindrical, 
stinct ;  x.  214  is  a  variety  in  which  they  |  rounded  at  both  ends,  and  provided  with 
are  strongly  marked.  In  clear  water,  j  delicate  elongated  bristles,  but  no  spines, 
amongst  Confervae.     1-620".  i  Fossil  in  flint,  near  Delitzsch.   1-1150". 

Genus  CH^TOGLENA. — Lorica  silicious,  destitute  of  a  transverse  zone 


576 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


or  furrow,  but  striped  or  covered  with  spines  or  stiiF  hairs,  and  ha\ing  an 
eye-speck.  The  organ  of  locomotion  is  a  simple  iiabellura.  The  interior 
contains  scattered  transparent  vesicles,  and  a  brownish-green  granular  mass ; 
a  large  bright  spot  or  nucleus  is  also  \dsible.     Self-division  not  observed. 

CiL^TOGLENA  volvocma. — Ovate,  with 


browmish-gTeen  granules,  and  a  red  eye  ; 
between  tlie  lorica  and  the  soft  body  a 
beautiful  red  ring  is  visible  in  live  spe- 
cimens (x.  216,  218).     Amongst  Confer- 


vas at  Hampstead  and  Hackney.  1-1150". 
C.  cauclata.  —  Hispid,  ovate,  with  a 
short  tail ;  granules  green ;  ocellus  clear 
red ;  oral  margin  urceolate  and  dentate. 
1-864".     Berhn. 


Genus  PEE.IDIjS'IUM. — Lorica  membranous,  with  a  transverse  ciliated 
zone ;  no  eye.  The  locomotive  organs  are  a  filament  and  the  zone  of  cilia. 
In  P.  Pulvisculus  and  P.  cinctum,  indigo  and  carmine  are  received,  and  de- 
monstrate the  formation  of  vacuoles,  which  in  P.  acuminatum,  P.  fulvum, 
and  P.  cornutum  are  visible  ^dthout  having  recoiu'se  to  colonized  food.  The 
oral  aperture  is  found  in  a  hollow  near  the  centre,  as  in  Bursaria.  The 
granules  are  generally  of  a  brown  or  yellowish-brown  colour,  though  some- 
times green  or  even  almost  colourless.  In  P.  Tripos  and  P.  Fusus  an 
oval  nucleus  is  visible.  Self-di\'ision  is  longitudinal  in  P.  Pulvisculus  and 
P.  fuscum ;  and,  according  to  some  observers,  transverse  in  P.  Fusus  and 
P.  Tripos. 

The  structural  peculiarities  are  sufficiently  described  in  the  chapter  on 
Peridiniaea  (p.  271).  The  existence  of  a  mouth  and  the  entrance  of  food  are 
still  matters  of  doubt.  A  nucleus  is  probably  present  in  all ;  and  the  same 
may  be  said  of  the  llabellum,  which  subsequent  observers  have  distinctly 
found  in  cases  where  it  eluded  the  observation  of  Ehrenberg.  "  Fossil  Peri- 
dhiia/^  says  Perty,  "  are  not  found  in  recent  geological  formations,  but  only 
in  the  chalk  bed^  of  the  secondary  strata,  in  which  they  occur  with  Xan- 
tliicUa  (Ehr.)  and  PyxidicuJoi.'" 

a.  Peridinia  luithout  horns. — Peribinium. 


Peridinium  cinctum  (  Vorticella  cincta, 
M.). — Nearly  globular,  or  slightly  three- 
lobed  and  smooth,  with  a  zone  of  cilia ; 
not  luminous.  It  swims  slowly,  with  a 
vacillating  and  rolling  motion.  Amongst 
Coufervpe.     1-570." 

Instead  of  the  red  zone  noted  by  Ehren- 
berg, there  may  be  only  a  single  speck, 
or  even  it  may  be  absent. 

P.  Pulvisculus. — Small,  of  a  brown  or 
gi'eenish-yellow  colour,  and  not  lumi- 
nous ;  almost  spherical,  or  slightly  three- 
lobed ;  a  fine  filament  2i  lines  longer 
than  the  body  may  be  observed ;  nume- 
rous vacuoles  produced  by  feeding  on  in- 
digo. Amongst  Conferva),  with  Cldami)- 
domonas  Pulvisculus.  1-2300"  to  1-1150". 

Perty  has  met  with  specimens  having 
a  red  speck. 

P.  fuscum. — Is  not  luminous;  oval, 
slightlv  compressed  and  pointed  ante- 
riorly.'  1-430"  to  1-280". 

P.'  Monas. — Very  small,  obtuse,  with- 
out horns  ;  remarkaljlv  social.  Diam. 
1-1728".     In  the  Baltic. 

Pertv  suffg-ests  that  this  is  merely  a 


young  stage  of  P.  ( Ceratium)  cornutum. 

P.  Planulum  (Perty). — Rounded,  broad, 
rather  compressed;  the  two  segments 
equal.  Colom*  brown,  usually  a  deep  tint. 
Under  surface  rather  concave.  1-720"  to 
1-430".  Its  brown  contents  contract 
after  death  into  a  central  lump.  A  red 
speck  is  often  seen  in  the  posterior  por- 
tion. It  is  distinguished  from  Glenodi- 
iiium  cinctutn  by  its  greater  width  and 
deeper  colom*. 

P.  Corjmsculum  (Perty). — Small ;  seg- 
ments very  unequal,  posterior  one  very 
short  and  cleft.  Granular  contents 
bro^^Tiish-yellow,  or  red  or  green.  An 
alteration  in  figure  has  been  seen  to 
ensue  after  death.  1-1120".  Amongst 
3Iarchantia  poli/morpJia. 

P.  momulicum  (Perty). — Very  small; 
segments  unequal,  the  posterior  one 
much  smaller ;  with  red  stigma  in  the 
line  of  constriction,  more  seldom  in  the 
hinder  half  Molecules  pale  green.  It 
is  the  smallest  known  example  in  this 
family.  1-1150".  In  a  pond  on  Mount 
St.  Gothard  and  at  Bern. 


OF  THE  PEliIDmiJ<:A. 


07/ 


P.  uberrimum  (Allman).  Nearly  sphe- 
rical ;  coloiu'  reddish-brown ;  nucleus 
well-defined,  central.  A  secondary  fur- 
row springs  vertically  from  the  annidar 
one,  and  terminates  at  the  pole.  A 
stigma  usually  present  at  the  polar  ex- 
tremity of  the  vertical  furrow.     S^^dms 

b.  PericUnia  with  horns 

P.  (Ceratium)  (?)  pyrophoi'um. — 
Ovate,  spherical,  with  two  little  elevated 
points  at  its  anterior  extremity.  It  is 
very  delicately  areolate  and  gi-anular. 
Fossil  in  the  flints  of  the  chalk  forma- 
tion at  Berlin.     1-570'  to  1-480". 

P.  (Ceratium)  (?) Belitieme. — Ovate, 
spherical;  with  a  little  stiff  point  near 
the  middle  laterally.  Fossil  in  the  flints 
ofDelitzsch.  1-430"  to  1-280".  These 
two  supposed  fossil  Peridmia  and  the 
Ch(etotifphIa  (?)  pyritce  appear  rather  to 
be  sporongia  of  Algse. 

P.  (Ceratium)  acuminatum. — ^Brown- 
ish-yeUow;     ovate,    spherical,    slightly 
three-lobed,    and    having   a   little  pro- 
cess at  the  posterior  end.     ''  I  observed  j 
this  species/'  says  Ehrenberg,  "  in  phos-  | 
phorescent  sea-water  from  Kiel,  and  it  is  I 
veiy  probable  that  the  light  proceeded 
from  this  animalcule.     It  is  the  smallest  i 
phosphorescent  sea   animalcule  that   is 
bio^vTi."     1-600"  to  1-570". 

P.  (CERATirM)  cornutum  (Pursana 
Himndinella,  M. ;  Ceratium  Hirundinella, 
Duj.  and  Perty). — Greenish ;  not  lumi- 
nous; rhomboidal  and  rough,  with  one, 
two,  or  three  straight  horn-like  processes 
in  front,  and  a  single  one  (often  curved) 
posteriorly.     1-280"  to  1-140". 

Perty  asserts  that  Ehrenberg  has  re- 
versed this  animalcule  in  his  account 
and  illustrations,  as  he  has  likewise  done 
in  other  species  of  this  genus ;  for  it  is 
the  single  horn  which  advances  fore- 
most, and  indicates  the  anterior  extre- 
mity. The  same  author,  moreover, 
states  that  in  the  majority  of  speci- 
mens one  or  more  red  specks  are  to  be 
found,  generally  in  the  posterior  half, 
near  the  middle  line  between  the  large 
and  small  homs. 

P.  (Ceratium)  TriiJOs  (  Cer carta  Tripos, 
M.).  — Yellow,  brilliantly  phosphores- 
cent; urceolate,  broadly  concave,  smooth, 
and  three-horned ;  the't^-o  frontal  horns 
very  long  and  recurved ;  the  third,  or  pos- 
terior one,  straight.  Ehrenberg  says, 
".  "^^^  power  of  this  creature  to  evolve 
light  is  placed  beyond  all  doubt,  as  I  took 
up  nine  phosphorescent  drops,  one  after 
the  other,  from  the  water,  and  I  saw  in 
each  nothino-  else  besides  a  sinele  animal- 


actively  by  the  aid  of  its  flabeHum,  and 
of  cilia  generally  disposed  on  the  surface, 
and  not  confined  to  the  fuiTOws  as  Ehr- 
enberg represents.  Occm-s  in  a  quies- 
cent state.  1-1000"  to  1-500".  Ponds, 
Phoenix  Park,  Dublin. 


— Subgenus  Ceratium. 

cule  of  this  species."  It  is  rigid,  and  swims 
with  a  vacillating  rolling  motion  upon 
the  longitudinal  axis.  The  length  of  the 
horns  is  not  constant,  sometimes  being 
scarcely  so  long  as  the  body,  at  other 
times  much  longer,  x.  219,  220,  repre- 
sent an  under  and  side  view.  In  the  sea, 
near  Copenhagen  andKiel.  1-140";  with- 
out the  horns^  1-430". 

P.  (Ceratium)  Michaelis.  —  Colour 
yellow ;  intenseh'  phosphorescent.  Lo- 
rica  ovate  and  smooth,  with  three  short, 
straight  horns,  as  shown  in  fig.  221.  A 
flagellum  is  not  visible.  In  phosphores- 
cent sea-water.  1-570".  Named  after 
Dr.  Michaelis,  its  discoverer. 

^  P.  (Ceratium)  Fusus  (x.  222, 223).— 
Yellow,  intensely  phosphorescent;  ovate, 
oblong,  and  smooth.  The  two  horns  are 
straight  and  extended  in  opposite  direc- 
tions, producing  a  fusiform  fig-ure.  Ehr- 
enberg states  that  he  has  seen  the  cilia 
of  the  furrowed  zone,  and  the  single  fila- 
ment when  at  rest ;  also  an  opening  or 
mouth  in  the  lorica,  near  the  insertion 
of  the  filament.  With  horns,  1-120"  to 
1-90". 

P.  (Ceratium)  Ftirca. — Yellow,  very 
phosphorescent;  urceolate,  TN-ith  three 
horns ;  two  in  front  short,  in  the  form  of 
a  fork;  one  behind  longer.  In  phos- 
phorescent water,  at  Kiel.     1-120". 

P.  (Ceratium)  divergens. — Y^ellow; 
cordate-ovate,  smooth ;  with  two  diver- 
gent frontal  acute  spines,  dentate  at  the 
base  ;  posterior  portion  attenuated,  look- 
ing as  if  shortly  homed.  Diam.  1-576". 
In  the  Baltic. 

P.  (Ceratium)  macroceros. — Yellow; 
habit  of  P.  Triptos,  but  more  slender,  and 
with  longer  horns,  which  are  four  times 
the  length  of  the  body.  1-216".  In 
the  Baltic. 

P.  Tridens. — YeUow,  with  the  habit 
oi  P.Jlarum,  P.  divergens,  and  of  P.  Mi- 
chaelis; surface  granular,  with  three  acute 
frontal  horns,  and  its  posterior  portion 
attenuate.     1-576".     In  the  Baltic. 

P.  (Ceratium)  macroceras  (Schrank) 
or  C  longicortie  (Perty)  is  mentioned  by 
Perty,  and  does  not  appear  quite  equiva- 
lent to  C.  macroceros,  to  which  its  name 
is  too  much  alike.  It  is  the  largest  of 
2  p 


578 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


all  the  Peridiuiaea,  and  (says  Pei-ty)  not 
a  variety  of  P.  cornutum,  as  Ehrenberg 
thought :  the  lorica  is  rather  concave 
below,  and  less  bent  than  in  that  species. 
Empty  loricse  are  clearly  areolate,  and 
the  areolae  round.  A  red  stigma  is  often 
seen  in  the  posterior  half.  The  anterior 
supports  a  single  horn,  and  there  are 
three  behind.     1-120"  to  1-96." 

P.  arcticum  (Ehr.)  resembles  P.  ina- 
croceros,  but  is-  stronger,  and  has  its 
large  horns  all  curbed  and  three  or  four 
times  longer  than  the  body;  surface 
rough,  ^^dth  little  raised  puncta  or  spines. 
Length  of  body,  1-48"',  of  entire  being 
1-18"'.  It  is  phosphorescent,  and  found 
at  Kingston  Bay,  Ne^^^folmdland,  with 
P.  Fiirca,  P.  Tridcns,  and  P.  divergens. 

P.  longipes  (Bailey). — Body  triangular, 
rough ;  angles  produced  into  very  long 
ciliated  processes,  of  which  the  two 
fi'ontal  ones  are  longest.  Body  crossed 
obliquely  by  a  ciliated  gTOOve  (xxxi.  23). 
St.  George's  Bank,  New  York. 


j  P.  depressum  (Bailey).  —  Lorica  ob- 
liquely depressed,  with  one  large  conical 
posterior  process,  and  two  smaller  conical 
frontal  processes;  the  latter  separated 
by  a  deep  notch.  Surface  granular  and 
reticulated.  Both  this  and  the  precedino- 
species,  which  were  found  together,  were 
doubtless  furnished  with  a  proboscis 
when  living,  and,  like  other  marine 
species  of  this  genus,  were  probably 
phosphorescent.  The  form  of  P.  depres- 
sum is  closely  analogous  to  the  embryo 
of  Nereis,  whose  curious  changes  were 
studied  by  Loven  (and  referred  to  in 
Prof.  Owen's  Lectures  on  the  Inverte- 
brata,  ed.  1843,  p.  147).  This  account  of 
Nereis,  and  particularly  the  comparison 
of  Prof.  Owen's  figure  with  the  Peridi- 
nium  depressum  (xxxi.  21,  22),  led  Dr. 
Bailey  to  suspect  that  at  least  a  portion 
of  the  forms  now  included  in  the  genus 
Peridinium  might  be  imperfectly-deve- 
loped or  embryonic  Annelida. 


Genus  GLENODINIUM. — Peridinia  with  motile  cilia  placed  in  a  trans- 
verse furrow  or  zone,  and  provided  with  an  eye.  The  organization  is  much 
the  same,  in  other  respects,  as  that  of  the  preceding  genus.  In  G.  cinctum  a 
flabellum  is  seen  to  emanate  from  the  middle,  and  to  vibrate  Kke  the  wreath 
of  cUia.  It  is  also  probably  present  in  the  other  species,  though  hitherto 
.unobserved.  The  lorica  is  combustible.  Vacuoles  and  fine  granules  are 
visible  in  all  the  species ;  the  former  are  veiy  distinct  in  G.  apicuJatum.  The 
red  speck  is  in  the  form  of  an  elongated  or  horseshoe-shaped  spot,  and 
constitutes  the  essential  character  of  the  genus.  Longitudinal  self-division 
has  been  observed  only  in  G.  cinctum. 

Although  this  genus  is  rejected  by  Dujardin  as  indistinguishable  from 
Peridinium,  yet  Perty  retains  it,  making  its  point  of  separation  from  the 
latter  genus — which,  by  the  way,  he  prefers  to  call  Ceratium — consist  in  the 
absence  of  horns  to  the  loiica.  The  red  speck  he  ignores,  equally  with  Du- 
jardin, as  a  distinctive  character.  In  this  way  Perty's  Glenoclinmm=- Peri- 
dinium, without  horns,  of  Ehr. 

Glenodinium  cinctum—  Peridimmn  |  G.(Peridimum)Alpimmi(PeYty). — The 
oculatum  (Duj.). — Oval,  or  nearly  sphe-  j  sculptm'ing  of  the  surface  is  indistiact; 
rical ;  smooth ;  stigma  large,  semi-lunar,  j  and  very  frequently  there  are,  alternately, 


and  transverse.  In  fresh  water,  amongst 
Oscillatorise.  1-570".  It  is  seen  both 
with  and  without  a  red  speck. 

G.  tabulatum. — Oval;  yellowish-green; 
lorica  granular  and  reticulate  with  ele- 
vated lines,  but  not  spinous;  truncate 
and  denticulate  posteriorly,  and  biden- 
tate  anteriorly.    1-570"  to  1-430". 

"  The  colour,"  says  Perty,  "  is  mostly 
brown,  especially  in  mature  specimens, 
and  more  rarely  brownish-green  or  gi-een. 
A  red  stigma  is  but  rarely  present." 


colom-ed  masses  of  granules  and  hyaline 
spaces  aroimd  the  border  of  the  lorica, 
producing  a  notched  appearance.  1-430". 
It  is  probably  only  an  Alpine  variety  of 
G.  tabulatum,  in  which  the  lorica  has  not 
attained  its  perfect  structure.  On  Mount 
St.  Gothard,  and  in  Lake  Lugano. 

G.  apiculatum.  —  Oval ;  yellowish- 
green;  lorica  smooth,  but  with  hispid 
furrows  on  the  margin,  as  shown  in 
X.  226.  The  stigma  is  oblong,  and  ex- 
tremities obtuse.  Amongst  Confervje. 
1-570"  to  1-430". 


OF  THE  VOKTICELLINA.  579 

FAMILY  III.— VORTICELLINA.     (Part  I.,  p.  277  et  seq.) 
(Plates  XXYII.,  XXIX.,  XXX.) 

Polygastrica  with  an  alimentary  canal,  the  extremities  of  which  are  distinct, 
though  they  approximate  in  consequence  of  its  curvature  (Anopisthia).  They 
have  no  lorica.  A  few  are  solitary ;  but  the  majority  are  congregated  on 
pedicles,  which  often  assume  elegant  ramose  forms,  like  little  trees,  an  ani- 
malcule surmounting  and  terminating  each  branch  or  pedicle.  These  arbo- 
rescent clusters  are  the  result  of  imperfect  self-division. 

The  animal  organization  of  this  family  is  very  distinct.  The  entire  sui'- 
face  of  Stentor  is  covered  with  vibratile  ciha ;  but  in  other  genera  they  are 
mostly  disposed  in  the  form  of  a  wreath  around  the  head.  In  some  genera, 
as  in  Vorticella,  Carchesium,  and  Opercularia,  longitudinal  and  transverse 
muscles  are  seen ;  the  mouth  and  discharging  opening,  both  lying  in  the 
same  lateral  cavity,  have  been  demonstrated  in  all.  Self- division  takes 
place  in  all  the  genera,  but  is  least  frequently  observed  in  Zootliamnium  : 
when  it  is  imperfect,  not  affecting  the  pedicle,  it  gives  rise  to  branching 
forms.  Gemmation  is  also  frequent  in  most  genera.  Prom  theii'  great  irrita- 
bility when  approached,  may  be  presumed  the  existence  of  a  system  of  sensa- 
tion. Colouring  matter  is  received  by  all  the  species  ;  eye-specks  are  wanting. 

This  family  affords  (in  form  indeed  rather  than  in  structural  homologies)  a 
connecting  link  between  the  Ciliata  (Polygastrica)  and  Rotatoria. 

The  following  curious  particulars  are  appended  by  Ehrenberg,  who  re- 
garded them  as  indicative  of  an  act  of  transformation  : — 

"  The  Vorticella  developes  a  pedicle  ;  divides  (casts  its  exuvia) ;  developes 
posterior  cilia ;  loosens  itself  from  the  pedicle,  rambles  about ;  draws  in 
(after  shedding  a  second  exmia)  the  posterior  cilia,  sheds  them,  and  &mly 
attaches  itself,  preparatory  to  putting  forth  another  stalk.  This  cycle  of 
phaenomena  is  repeated  again  and  agam,  and  possesses  high  physiological 
interest ;  it  is  a  retui^ning  circle  of  transformations — a  retium  to  an  early 
condition,  similar  to  that  of  a  butterfly,  if  it  suddenly  lost  its  wings  and  an- 
tennae, and  again  became  a  caterpillar,  in  order  once  more  to  return  to  the 
state  of  pupa  and  buttei-fly — or  to  that  of  an  old  man  becoming  a  child,  in 
order  to  run  again  his  course  of  life  anew."  (See  Part  I.  p.  277  et  seq.,  and 
p.  586.) 

The  Yorticellina  live  for  the  most  part  in  sweet  water,  fresh  or  marine, 
attached  to  plants  or  shells,  to  Crustacea,  to  the  larvae  of  insects,  (fee.  There 
are,  however,  a  few  Vorticellce  and  ^cyphidece  produced  in  infusions,  and  even 
in  fetid  ones. 

This  account  of  the  organization  of  Yorticellina  from  Ehrenberg  requires 
considerable  alterations  and  corrections  from  the  present  state  of  our  know- 
ledge of  these  beings.  In  Part  I.  (p.  277),  their  organization  has  been  largely 
considered ;  yet  a  few  notes  here  may  not  be  misplaced  Any  definition  of  the 
characters  of  the  group  of  genera  comprehended  in  this  family  by  Ehrenberg 
would  be  imsatisfactory,  inasmuch  as  some  forms  are  included  which  have 
no  sufficient  affinity.  Ehrenberg  represents  the  Yorticellina  as  ha\dng  a 
polygastric  alimentary  canal  so  curved  that  its  two  ends  are  conterminous. 
Now  the  supposed  stomachs,  as  displayed  by  using  coloured  food,  were  merely 
vacuoles  ;  and  no  continuous  alimentary  canal  penetrates  the  interior,  as  sup- 
posed, but  only  a  digestive  tube  or  oesophagus  of  variable  length,  terminating 
abruptly  in  the  interior  by  an  open  mouth.  The  ciliary  apparatus  of  the  true 
Yorticellina  is  more  complex  than  appeared  to  Ehrenberg, — the  head  of  the 
animalcules  being  terminated  by  a  peristom  or  free  edge,  oftentimes  thickened 
and  everted,  bevond  which  a  ciliated  disc  supported  on  a  very  retractile  and 

2p2 


580  SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 

higUy  sensitive  pedicle  can  be  protnided.  The  portion  of  the  ciliary  spii-al 
outside  the  vestibuliim  is  not  of  equal  length  in  aU  Yorticellina  :  in  many, 
e.  g.  Vorticella,  Carcliesimn,  ZoGthamniiim,  Scyphidia,  Trichodina,  some  species 
of  Epistylis,  (fee,  it  describes  scarcely  more  than  one  circuit  round  the  disc, 
whilst  in  Opercidaria  articulata  and  Epistylis  Jiavicans  it  runs  round  the  disc 
three  times ;  in  other  species  intermediate  lengths  occur.  The  ciliary  wreath, 
moreover,  consists  of  a  double  row  of  cilia :  those  of  the  outer  one  are  usually 
somewhat  shorter  than  those  of  the  inner,  and  though  inserted  upon  the 
margin  nearly  in  the  same  line  as  the  others,  yet  they  are  set  at  a  different 
angle,  and  apparently  far  more  strongly  bent  outwards.  In  the  vestibulum 
and  oesophagus  the  cilia  appear  to  stand  in  a  single  row.  The  peristom  usually 
bears  no  cilia.  There  is  no  sufficient  proof  of  the  existence  of  muscles  of  the 
same  type  as  those  of  the  higher  classes  of  animals.  The  contractile  vesicle 
is  single  and  circular ;  the  nucleus  sometimes  oval,  but  often  elongated  and 
band-hke.  Besides  fission  and  gemmation,  tine  propagation  by  lining  germs 
or  embryos,  developed  in  the  coui^se  of  more  or  less  complete  transformations, 
affords  an  additional  means  of  perpetuating  and  extending  the  several  species. 
The  genera  are  distributed  as  follows : — 

{Body  covered  with  ciHa Stentor. 
Body  smooth,  cilia  anterior Trichodina. 

Tail  present    Urocentriim. 

f  Stalk  flexible,      f  ^^P^^ VorticeUa. 

Form  of  stalked  J  deflection  spkal    \  -o        i    j        n      i,    • 
bodies  similar  \  ^  ^  Branched        Carchesium. 

Body  stalked-often  ^  \^^^^^  m^e^hXe  EpistyHs. 

branched  like  a  tree   '  ^  -^    "^ 

Bodies    of    aif- J  ^^^^  ^^^^^^^  Opercularia. 

ferent  form  ...  |  g^^^j.  jSexible,  deflection  spiral... Zoothamnium. 

Of  the  several  genera  named  and  distinguished  by  Ehrenberg,  two  only 
are  accepted  by  Dujardin,  yiz.  Epistylis,  with  a  rigid  pedicle,  and  VorticeUa, 
with  a  contractile  stalk,  simple  or  branched.  He  places  Carchesium  with  the 
latter,  maintaining  that  a  generic  character  is  not  to  be  found  in  the  simple 
or  branched  condition  of  the  stalk  alone,  when  the  bodies  are  similar.  More- 
over, he  failed  to  meet  with  animalcules  having  the  characters  assigned  to  the 
genera  Opercularia  and  Zoothamnium.  by  Ehrenberg.  A  tliird  genus,  imder 
the  name  of  Scyphidia,  is  established  by  him  for  the  sessile  species ;  whilst 
a  fourth,  Vaginicola,  comprises  all  those  species  invested  with  a  membranous 
sheath,  and  corresponds,  in  its  constituent  species,  to  the  family  Ophrydina 
(Ehr.)  after  the  exclusion  of  Ophrydium. 

Perty  makes  a  different  distribution  of  the  Yorticellina  to  that  proposed 
by  Ehrenberg.  Like  Dujardin,  he  rejects  the  genera  Stentor  and  Urocentnm, 
and  transfers  them  to  a  family  Urceolarina.  On  the  other  hand,  he  adds 
Scyphidia  of  Dujardin  to  the  true  Yorticellina,  and  makes  no  mention  of 
Carchesium.  Lachmann  is  another  writer  who  rejects  Urocentrum  from  the 
Yorticellina.  Stein  points  out  various  defects  in  Ehrenberg's  grouping  of 
Yorticellina  ;  and  whilst  he  would,  on  the  one  hand,  detach  from  it  Stentor, 
Trichodina,  and  Urocentmun,  he  would,  on  the  other,  associate  with  it  the 
several  sheathed  genera  which  form  the  family  Ophrydina,  viz.  Ophrydium, 
Vaginicola,  Tintinnus,  and  Cothurnia.  Apart  fi'om  these  changes  in  the  distri- 
bution of  admitted  genera,  he  adds  two  new  ones,  Lagenophrys  and  Spirocliona, 
remarking  of  the  former,  that,  in  its  free  condition,  it  constitutes  a  transi- 


or  THE  VORTICELLIXA.  581 

tional  form  between  the  radiated  type  of  Vorticellina  and  the  bilateral  one  of 
Oxytrichina  and  Eiiplotina.  Lastly,  Lachmann  states  that  Trichodina  and 
Urocentrum  are  not  YorticeUina,  and  makes  Stentor  the  representative  of  a 
new  family,  which  he  calls  Stentorinse.  In  this  proposed  new  family  he 
includes  besides  Stentor,  a  new  genus  (Chcetospira),  Spirostomum,  and  a 
fourth  genus  which  he  has  merely  referred  to  without  naming  or  de- 
scribing it.  In  the  above  plans  of  classification  there  is  this  in  common, 
that  the  genera  Stentor,  Trichodina,  and  Urocentrtim  are  excluded  from 
among  the  Vorticellina,  an  exclusion  warranted  by  their  difference  of  organ- 
ization and  general  characters.  At  the  same  time  we  are  of  opinion  that 
the  association  of  the  Ophrydina  "uith  the  YorticeUina  is  not  correct  in  a 
systematic  point  of  \iew,  the  existence  of  external  sheaths  being  a  weU- 
marked  and  sufficiently  distinctive  character,  although  the  homology  in  organ- 
ization is  otherwise,  in  every  essential  point,  very  close  and  striking.  Pro- 
bably Trichodina  and  Urocentrum  should  constitute  an  allied  family  or  a 
sub-family  of  YorticeUina  ;  Stentor  the  type  of  a  second  family  ;  whilst  the 
remainder  of  Ehrenberg's  group,  viz.  Vorticella,  Carchesium,  Epistylis,  Ojper- 
cularia,  and  Zoothamnimn,  might  be  caUed  the  true  YorticeUina.  The  new 
genus  Spirockona,  again,  stands  apart  by  so  many  pecuUarities  that  it  cannot 
be  included  within  either  of  the  groups  proposed,  and  must  be  regarded  as 
the  (at  present)  soUtary  type  of  a  new  family,  having  the  internal  organization 
of  YorticeUina,  but  destitute  of  their  peculiar  ciUated  head.  In  framing  his 
generic  and  specific  distinctions,  Elu-enberg  made  use  of  characters  of  no  real 
value, — such,  for  instance,  as  the  occurrence  of  simUar  and  dissimilar  bodies 
(zooids)  on  branching  stems  otherwise  alike,  the  height  of  the  stem,  the  thick- 
ness of  its  branches,  and  the  dimensions  of  the  attached  animalcules. 

The  family  Urceolarina  (Duj.)  is  thus  characterized: — "Animals  variable 
in  form,  changing  from  a  trumpet-  or  a  hemispherical  to  a  globular  form ; 
cihated  throughout,  with  a  fringe  of  much  stronger  cilia  along  the  upper  and 
anterior  margin  of  the  body,  continued  as  a  spiral  coU  into  the  oral  cavity, 
which  is  on  the  same  border.  They  present  the  ordinary  swimming  move- 
ment, and  can  for  a  short  time  arrest  their  progress  by  fixing  themselves  by 
their  posterior  extremity  to  external  objects."  "This  famUy,"  observes 
Dujardin,  "  connects  the  YorticeUina  with  the  Bursarina,  and  includes  the 
genera  Stentor,  Urceolaria  {Trichodina,  Ehr.),  Ophrydium,  and  Urocentrum.^' 
The  last-named  genus  is  treated  as  very  doubtful.  As  already  seen,  Perty 
adopts  this  family  Urceolarina,  but  modifies  it  by  rejecting  Ophrydium,  and 
adding  Spirostomum. 

Genus  STEOTOR  (XXYIII.  16, 17 ;  XXIX.  8).— Animal  without  pedicle, 
free,  or  attached  by  the  posterior  extremity  of  the  body,  which  is  conical, 
although  it  admits  of  very  considerable  modifications  of  form ;  it  is  entirely 
covered  with  ciUa ;  a  wreath  of  larger  ones  surmounts  the  head.  Ehrenberg 
considered  the  longitudinal  striae  along  the  body,  and  the  circular  ones  at  the 
anterior  part,  muscular  fibres.  The  anterior  cUiary  wreath  is  coiled  in  a 
spiral  manner  about  the  head ;  in  some  species  a  row  of  longer  ciUa  extends 
from  the  mouth,  in  a  fringe-Uke  mamier,  to  the  middle  of  the  body.  The 
Stentors  increase  by  self- division,  which  is  either  longitudinal  or  obhque. 
The  nucleus  is  band-like,  monUiform,  or  round.  The  contractUe  vesicle  is 
large,  round,  and  placed  on  a  level  with  the  ciUary  T^Tcath,  close  to  the 
oesophagus  ;  it  gives  off,  above,  an  annular  branch,  which  surrounds  the  head 
of  the  animalcule  just  beneath  the  fringe  of  cUia,  and  below,  a  straight 
branch  extending  to  the  posterior  extremity  of  the  animalcule  (XXIX.  7). 
The  anus  may  often  be  perceived  for  a  considerable  time  both  before  and 
after  the  discharge  of  matters.     It  is  situated  on  the  back,  close  beneath  the 


582 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


ciliarj^  circle.  The  Stentors  are  among  the  largest  of  the  Infusoria,  and  all 
the  species  are  visible  to  the  unassisted  sight.  They  are  best  examined 
between  the  plates  of  a  large  live-box,  a  portion  of  the  decayed  stem  or  leaf 
on  which  they  are  found  being  put  in  with  them. 

"  It  is,"  says  M.  Dujardin,  "•  in  the  Stentors  where  we  can  view  the  several 
supposed  internal  organs  isolately,  that  new  observations  will  make  known 
theii'  real  nature." 

They  are  exclusively  found  in  fresh  standing  water,  or  between  plants 
where  the  water  is  still.  Some  of  them  are  colourless,  others  green,  black, 
or  clear  blue. 

This  genus  gives  name  to  the  family  Stentorina  proposed  by  Lachmann 
and  others,  and,  in  the  classification  of  Dujardin  and  Perty,  is  a  member  of 
the  family  Urceolarina  (p.  581). 


Stentor  MUUeri  (xxvni.  16,  17). — 
This  is  the  "  white  funuel-like  polpye  " 
discovered  by  Trembley ;  it  is  large,  the 
crown  or  wreath  of  cilia  interrupted,  and 
the  lateral  crest  or  fringe  indistinct; 
when  outstretched  it  is  trumpet-shaped, 
but  in  its  contracted  state  is  ovoid ;  and 
during  division,  or  when  the  water 
around  it  evaporates,  a  muco -gelatinous 
mass  is  thrown  out  as  an  external  cover- 
ing. When  several  are  swimming  in  a 
glass  vessel,  they  will  gradually  congre- 
gate, and  select  some  particular  spot, 
and  then  attach  themselves,  evincing,  as 
Ehrenberg  imagined,  not  only  a  degree  of 
sociality,  but  of  mental  activitj^  These 
animalcules  receive  coloured  food  very 
readily ;  nucleus  monilifovm.  Upon 
Lemnae    and    other  water-plants,    even 


under 


Size,  stretched  out,  1-20": 


Ehrenberg  referred  to  the  exudation  of 
a  mucilaginous  coat  as  the  prelude  to  the 
death  of  the  Stentor ;  but,  as  Cohn  has 
shown  {Zeitsclir.  Band  iii.  p.  26.3),  it 
takes  place  in  perfectly  healthy  and  live- 
ly animals,  and  is  an  instance  of  the 
widely-pervading  process  of  encystmg. 
This  observer,  indeed,  tells  us  that,  when 
the  conditions  of  existence  become  un- 
favourable, animalcules  preidously  at- 
tached by  their  tapering  posterior  ex- 
tremity, as  by  a  sucker  resembling  that 
of  a  leech,  free  themselves  from  their 
capsular  envelope  and  swim  away,  dis- 
playing then  a  brush  of  cilia  at  the  end 
of  the  tail.  The  notion  of  a  sentiment 
of  sociality  and  of  mental  activity,  sur- 
mised by  the  Berlin  niicroscopist,  de- 
mands the  exercise  of  a  powerful  imagi- 
nation to  realize  it.  Dr.  Wright  most 
kindly  notices,  in  a  letter  to  us,  that 
Stentor  Mi'dlcri  always  secretes  a  gela- 
tinous case  into  which  it  can  retract. 
As  the  zooids  divide  they  form  a  gela- 
tinous mass,  which  is  attached  to  weeds 


and  often  to  the  surface  of  the  water, 
from  which  10  or  15  Stentors  aggregated 
together  may  sometimes  be  seen  hanging 
with  their  lieads  do\^^n wards.  The  ex- 
ternal gelatinous  sheath  in  Stentor  and 
other  Vorticellina  and  Ophrydina,  Dr. 
Wright  proposes  to  call  the  "coUeto- 
derni,"  as  the  homologue  of  the  gela- 
tinous matter  covering  the  polypidonis 
of  the  Hydroidag. 

^  S.  RosseUi  (x.  2.33,  2-34).— In  form, 
size,  and  crest,  this  species  resembles  the 
preceding,  but  is  of  a  more  distinct 
yellowish-white  colour.  The  nucleus  is 
long,  ribbon-shaped,  and  not  monilifonn ; 
the  contractile  vesicle  (seen  at  *)  circular. 
Conunon  in  summer;  upon  decaying 
plants,  &c.,  in  standing  water.  1-liO"; 
extended,  1-24" 

The  monilifonn  intestine  represented 
by  Ehrenberg  was  very  probably  the  chain 
of  vesicular  dilatations  of  the  presumed 
vascular  system  connected  with  the  con- 
tractile vesicle,  and  which  is  largely  de- 
veloped in  the  Stentors,  on  one  side  of 
the  body,  as  a  canal  extending  from  a 
circular  sinus  aroimd  the  head.  Dujardin 
regarded  this  species  as  simply  a  variety 
of  S.  MiUleri\  and  there  is  no  apprecia- 
ble character  truly  distinctive  between 
them. 

S.  cceruleus  (xxix.  8)  resembles,  exte- 
riorly, the  two  preceding  species  ;  but  its 
granules  are  blue,  nucleus  articulated  and 
chain-like  (monilifonn).  It  is  trumpet- 
shaped  when  extended,  ovoid  when  con- 
tracted; white  or  semi-transparent,  ex- 
cept when  coloured  by  food.  The  lateral 
crest  and  frontal  wreath  are  continuous. 
When  kept  in  glass  vessels,  they  often 
fix  themselves  to  the  sides  in  chisters. 
They  are  best  examined  when  placed  in 
a  large  live-box ;  a  magnifying  power 
of  100  diameters  is  sufficient.  Amongst 
Vaucheri^e.     1-480". 

Except  its  much  smaller  size,  there 


OF  THE  VORTICELLINA. 


580 


seems  nothing  to  sufficiently  distinguish 
it  from  the  preceding  spacies ;  for  the 
bhiish  hue  of  the  granules  cannot  be 
admitted  as  a  characteristic.  Even  the 
difference  in  dimension  is  no  satisfactory 
indication  of  a  distinct  species ;  for  the 
smaller  animalcule  may  be  but  a  younger 
specimen  of  the  larger. 

S.  pohjmorplnis  (xxix.  7)  resembles 
the  preceding  in  form.  Granules  of  a 
beautifid  green  colour;  nucleus  articu- 
lated and  chain-like ;  lateral  crest  in- 
distinct; frontal  wreath  of  cilia  inter- 
rupted. This  species  will  not  receive 
indigo  readily.  Transverse  self-division 
observed.  Upon  stones,  decayed  sticks, 
and  leaves,  in  standing  water.  1-120"  to 
1-24". 

Lachmann  {A.  N.  H.  1857,  xix.  p. 
225)  seems  to  intimate  that  this  species 
is  equivalent  to  ♦S'.  Mulleri  and  S.  Rceselii. 
Both  in  this  species  and  in  *S'.  ccendeus 
Eckhard  has  described  reproduction  by 
internal  germs  or  embr^'os.  Between  the 
cilia,  disposed  in  spiral  series,  single  long 
hairs,  similar  to  those  of  many  Turbel- 
laria,  are  found,  according  to  the  testi- 
mony of  Lachmann. 


S.  iyneus. — Less  than  the  preceding; 
granules  yeUowish-green ;  smface  bright 
yellow  or  vermilion ;  nucleus  spherical ; 
lateral  crest  absent ;  frontal  ^\Teath  of 
cilia  interrupted.  Found  by  Ehrenberg 
upon  the  water- violet  {Hottonia  palus- 
:  tris).     1-72". 

I       S.  7iiger  (Vorticella  nigra,  M.). — Small, 

!  of  a  dark  browmish-yellow  or  blackish 

j  colour ;  granules  olive-coloured ;  nucleus 

spherical ;  lateral  crest  absent ;    frontal 

j  wreath  of  cilia  continuous.    This  species 

!  is  often  so  abundant  that  it  colours  large 

I  pools,  in  turfy  hollows,  of  a  dark  blackish 

I  hue,  resembling  an  infusion  of  coffee. 

The  sv^-imming  movement  of  this  species 

is  readily  seen  (as  in  the  others)  with 

the  naked  eye.     1-96". 

S.  castaneus  (Wright).  —  K  species 
named  in  a  letter  to  us  by  Dr.  Wright, 
of  which  the  only  particulars  given  are 
that  it  is  of  a  dark  chestnut  colour,  and 
that  it  selects  the  tops  of  the  stems  of 
Myriophyllum  as  its  home,  and  glues  all 
the  young  leaflets  together  with  a  baU 
of  jelly,  within  which  a  crowd  of  zooids 
is  imbedded. 


Genus  TRICHODINA.— Yorticellina  destitute  both  of  tail  and  pedicle, 
distinguished  from  the  preceding  genus  by  the  general  smface  of  the  body 
being  destitute  of  cilia.  They  possess  a  vibrating  wreath  of  cilia  anteriorly, 
on  one  side  of  which  is  a  simple,  not  spiral  oral  opening.  They  are  mostly 
disc-shaped  or  conical.  T.  Pediculus  has  the  posterior  end  abruptly  trun- 
cated like  the  front,  and  also  surrounded  with  a  wreath  of  curved  setae,  which 
it  employs  when  crawling,  in  the  manner  of  feet.  In  T.  tentaculata  there  is  a 
kind  of  proboscis.  Coloiu-ed  food  is  received  by  T.  Pediculus  and  T.  GrandineHa. 
A  kidney-shaped  nucleus  is  seen  in  T.  Pediculus.  Many  species  live  parasitic 
on  freshwater  MoUusca,  or  Zoophytes ;  but  others  have  been  found  free  in 
sea-water. 

This  description  by  Ehrenberg  conveys  a  very  imperfect  conception  of  the 
real  structure  and  appearance  of  Tricliodina.  The  following  account  and 
figures  from  Stein  will,  however,  supply  its  deficiencies : — "  The  genus  Triclio- 
dina consists  of  naked  and  highly  contractile  animalcules,  subject  to  very  con- 
siderable variations  of  form  in  the  direction  of  the  long  axis.  Their  usual 
figure  is  that  of  a  tiTincated  cone,  much  and  suddenly  distended  posteriorly, 
and  surmounted  at  their  wider  extremity  by  a  wreath  of  cilia,  which  corre- 
sponds with  the  posterior  ciliary  wreath  in  other  VorticeUina.  The  other, 
abruptly  truncate  extremity  is  furnished  with  an  apparatus  of  hooks  (XXIX. 
15),  whereby  the  animal  can  attach  itself  to  other  bodies.  The  mouth  is 
circular,  and  placed  on  one  side  of  the  body,  at  a  greater  or  less  distance  from 
the  anterior  extremity  ;  it  is  furnished  with  a  special  zone  of  cilia  to  aid  in 
the  introduction  of  the  alimentary  particles."  (It  is,  however,  not  circular, 
but  a  spii^al  fringe  of  cilia,  as  Dujardin  stated.)  The  genus  Trichodina  (Ehr.) 
agrees  in  the  main  with  Urceolaria  (Duj.). 

Of  the  several  species  enumerated  by  Ehrenberg,  Stein  asserts  that  two 
only  are  admissible,  that  the  other  three  are  foreign  to  the  genus,  and  very 


oSi 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


incompletely  observed  beings.  Thus  T.  Gnindinella  and  T.  vorax  appear  to 
be  merely  the  embiyos,  or  otherwise  the  gemmae,  of  Yorticellina,  whilst  T. 
tentaculata  is  imperfectly  known,  and  -^dll  probably  always  remain  a  ques- 
tionable organism.  Fui'ther,  this  author  would  unite  Trichodina  with  Urocen->- 
trum  into  a  subfamily  of  Vorticelhna. 

Lachmann  (A.  N.  H.  1857,  xix.  p.  119)  agrees  with  Stein  in  limiting  the 
genus  to  the  two  species  T.  Pedicuhis  and  T.  Mitra,  and  in  rejecting  the 
rest  as  not  Yorticellina  at  all.  According  to  him,  Trichodina  Grandinella  and 
T.  vorcw  are  rightly  referable  to  Halteria  (Duj.). 

Trichodina  tentaculata  (x,  227).  — 
Discoid,  destitute  of  the  wreath  of  cilia, 
but  with  a  fascicidus  of  vibratile  cilia, 


and  a  stylifonn  proboscis.     1-280 

T,  Pediculus  {Cyclidium  Pediculus,  M.) 
=  Urceolaria  stelUna  (Duj.)  (x.  228-230  j 
XXIX.  14, 15,  17). — Depressed,  urceolate, 
and  discoid,  with  a  wreath  of  vibratile 
cilia  anteriorly,  and  another  of  short 
moveable  micinate  cilia,  or  hooked  setoe, 
posteriorly.  Ehrenberg  remarks,  "  I  have 
fed  this  species  many  times  with  indigo, 
and  have  seen  numerous  stomachs  filled 
with  the  blue  ma,tter.  It  always  runs 
upon  the  back,  where  there  is  a  wreath 
of  24  to  28  mobile  hooks  (or  uncinate 
cilia),  and  has  the  mouth  and  vibrating 
wreath  of  48  to  64  cilia  directed  up- 
wards." It  appears  to  feed  upon  the 
little  granules  of  the  body  of  the  Fresh- 
water Pol}^e  (Hi/dra,  '  Microscopic  Ca- 
binet,' pi.  vii.)  (Figs.  228  and  229  are  side 
views,  attached  to  a  portion  of  a  poh^pe ; 
fig.  230  is  a  top  view).  1-570''  to  1-280". 
T.  Pediculus  (xxix.  14-17)  is  described 
in  much  detail  by  Stein  (Lifusionsthiere, 
p.  175).  "  It  has,"  he  writes,  "  a  turban- 
shaped  body ;  the  truncated  conical  an- 
terior segment  is  morphological  with  the 
rotary  organ  of  typical  Vorticellina,  and 
is  shorter  than  the  very  ventricose  and 
expanded  posterior  segment,  from  which 
it  is  separated  by  a  deep  annular  con- 
striction or  furrow,  occupied  by  a  wreath 
of  vibratile  cilia  of  less  length  than  those 
forming  the  posterior  zone.  The  oral 
aperture  is  seated  in  this  farrow,  the  cilia 
of  which  are  active  in  impelling  food 
into  the  mouth.  The  posterior  ciliary 
zone  is  parallel  with  the  one  in  front, 
j  ust  described,  and  occupies  the  posterior 
smface  of  the  hindmost  segment  of  the 
body,  near  to  the  line  of  attachment  of 
the  circlet  of  uncini,  as  can  be  best  seen 
when  the  animal  is  dead.  It  is  this  zone 
which  principally  serves  for  locomotion. 
The  anterior  segment  can  be  retracted, 
and  even  vanish,  by  being  taken  up  into 
the  posterior,  when  the  tigure  becomes 
cvlindrical,  with  abruptly  truncate  ends. 
"The  posterior  segment  also  contracts  it- 


self considerably,  and  in  so  doing  pre- 
sents several  annular  folds.  The  margin 
of  the  truncated  extremity,  which  is 
much  smaller  than  a  section  made  through 
the  middle  of  the  posterior  segment,  is 
fringed  by  a  firm  cartilaginous  or  horny 
ring,  having  both  on  its  outer  and  inner 
fice  a  series  of  uncini,  placed  at  equal 
distances  from  each  other,  and  some- 
what constricted  behind  the  origin  of 
each  pair.  The  inner  row  of  uncini  lie 
in  the  same  plane  as  the  posterior  sur- 
face; but  the  external  row  are  strongly 
turned  outwards  and  backwards.  Besides 
these  is  a  structure  not  hitherto  described, 
consisting  of  an  annular,  transparent, 
elevated  rim  or  collar,  often  of  a  slight 
yellow  colour,  and  of  a  horny  aspect^ 
placed  aroimd  the  outer  margin  of  the 
corneous  ring,  above  the  base  of  the 
outer  series  of  uncini.  It  is  extremely 
flexible,  directed  obliquely  outwards,  and 
marked  by  very  fine  lines.  The  circlet 
of  hooks  is  at  once  dissolved  by  acetic 
acid,  whilst  this  structure  remains ;  and, 
on  the  other  liand,  the  whole  prehensile 
apparatus  disappears  when  the  animal 
is  put  into  alcohol."  The  structm'e  of 
Trichodina,  as  now  imfolded  by  Stein, 
was  both  imperfectly  and  erroneously 
conceived  by  Ehrenberg. 

The  long  diameter  of  the  largest  Tri- 
chodina Pediculus  Stein  met  with  was 
1-360";  the  transverse  diameter  was 
about  the  same.  Small  specimens  oc- 
curred of  only  half  the  size,  but  complete 
in  all  the  details  of  organization. 

T.  vorax.  —  Oblong,  cylindrical,  or 
slightly  conical ;  anterior  part  convex, 
and  crowned  with  cilia ;  the  back  rather 
attenuated  and  smooth.     1-570". 

This  and  the  next  species  are,  from 
their  dissimilarity  to  T.  Pedicuhis,  re- 
mo^-ed  by  Dujardin  to  another  genus  he 
names  Halteria, — the  two  being  equiva- 
lent to  HalteriaGrandinella,  wliich  again, 
in  Stein's  opinion,  is  the  embryo  of  an 
Acinetiform  phase  of  a  Vorticella. 

T.  GrandineUa  (M.).— Nearly  spherical; 
sharply  attenuated  posteriorly ;  a  wreath 
of  cilia  surrounds  the  truncated  fore  part. 


OF  THE  VORTICELLINA. 


585 


This  species  is  liable  to  be  mistaken,  by 
an  inexperienced  observer,  for  a  free  Vo?-- 
ticella ;  its  true  distingnisliing  character 
appears  to  be  its  open  wreath  of  cilia. 
1-1500"  to  1-860". 

T.  Mitm  (Siebold)  (xxix.  16).— An- 
terior segment  elongated,  cylindrical, 
much  longer  than  the  slightly  wider  and 
more  discoid  posterior  segment,  into 
which  it  gradually  expands.  The  outer- 
most margin  of  the  posterior  segment 
has  a  similar  wreath  of  cilia  to  that  of 
T.  Pedicidus ;  but  the  prehensile  appa- 
ratus difiers  in  the  two  species.     In  T.  I 


Mitra  the  undulating  cartilaginous  ring 
is  not  armed  with  hooks,  but  has  only 
the  annular  membrane,  precisely  like 
that  in  the  other  species,  except  that 
it  is  relatively  smaller,  less  distinctly 
striped,  more  colourless  and  transparent, 
and  therefore  more  readily  overlooked. 
Between  the  two  segments  is  the  deep 
fmit)w  in  which  the  mouth  is  placed, 
from  which  a  row  of  cilia  extends  to- 
wards each  end  at  right  angles  to  the 
posterior  ciliary  zone,  and  is  homologous 
with  the  anterior  wTeath  of  cilia  of  T. 
Pedicidus. 


Genus  UEOCEjS'TEFM  (X.  231,  232).— Free,  with  a  tail-like  style,  but 
no  pedicle,  and  no  cilia,  except  a  wreath  anteriorly ;  oral  aperture  simple. 
Self-division  transverse.  Ehrenberg  thinks  the  eyes,  which  MiiUer  supposed 
he  had  seen,  were  most  probably  the  traces  of  cilia,  which  he  appears  to  have 
overlooked. 

Ubo CENTBUM  jTi^rSo  {Cercciria  Turho,  j  ticella-^toW,  but  an  articulated  style  on 
M.)  (x.  231,  232). — Hyaline,  ovate,  tri-  j  the  back — perhaps  a  foot."  WithLemnae 
lateral,  with  a  style,  or  setaceous  tail,  I  and  Confervpe.     Fig.  232  a  dorsal,  231  a 
one-third  of  its  length.    Ehrenberg  says,  {  side  view.     1-430"  to  1-280". 
"  The  little  tail  is  not  a  separable  Voy-  \ 

Genus  A^OETICELLA  (XXYII.  1-5).— Crowned  with  cilia  anteriorly; 
stalked  when  young,  but  at  a  later  period,  and  also  after  self-division,  sessile. 
The  shape  of  the  zooids,  when  stalked,  is  similar ;  the  pedicle  can  be  suddenly 
deflected  spirally,  by  means  of  the  long  muscle  within  it,  but  it  is  never 
branched.  At  certain  periods  a  second  wreath  of  cilia  is  produced  at  the 
posterior  part  of  the  body.  Xot  only,  according  to  Ehrenberg,  can  numerous 
stomach- cells  be  seen,  but  likewise  the  gradual  passage  of  the  food  onwards, 
in  a  twining  sort  of  intestinal  canal,  though  this  is  not  easily  observed,  on 
account  of  the  periodical  deflection  of  the  pedicle.  However,  in  the  genera 
Epistylis  and  Opercidaria,  whose  pedicles  are  comparatively  motionless,  the 
nutritive  apparatus  may  be  much  more  perfectly  investigated.  The  mouth 
and  discharging  orifice  are  separate,  but  he  in  the  same  hollow,  at  the  anterior 
margin.  The  granules  are  variously  coloured,  and  constitute,  in  Ehrenberg's 
language,  clusters  of  ova  ;  nucleus  elongated,  contractile  bladder  round.  The 
animalcules  are  androgynous.  The  supposed  increase  by  the  growth  of  young 
animalcules  out  of  the  pedicle  (or  of  gemmae),  Hke  flowers  on  the  stem  of  a 
plant,  has  arisen  from  erroneous  observation.  When  the  animalcule  loosens 
itself  from  its  pedicle  or  stalk — a  circumstance  which,  says  Ehrenberg,  ''  takes 
place  at  certain  periods — the  stalks  die,  or  disappear,  just  like  the  shells  of 
crabs,  or  as  the  nails  and  hair."  The  muscular  fibre  within  the  stem  requii'es 
stops,  or  an  achromatic  condenser,  under  the  stage,  to  render  it  distinct. 

The  VorticeUce  being  of  so  considerable  a  size,  and  easily  procurable,  have 
formed  the  subject  of  numerous  investigations  into  their  organization ;  but 
yet  no  observers  have  been  able  to  coincide  entirely  with  the  views  of 
Ehrenberg.  Among  the  most  recent  researches  are  those  of  Prof.  Stein, 
which  have  been  fuUy  put  forward  in  the  general  history  of  these  animals, 
to  which  we  must  refer  (see  p.  277  et  seq.).  Suffice  it  to  say  that  the 
winding  intestinal  canal,  the  distinct  stomach- cells,  the  clusters  of  ova,  the 
androgynous  nature  mentioned  in  the  above  account  from  Ehrenberg  of  the 
internal  organization  of  VorticeUce,  have,  not  only  in  Stein's  opinion,  but  in 


586  SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 

that  of  nearly  every  other  naturalist,  no  existence  ;  the  appearances  so  inter- 
preted are  explicable  in  a  different  manner.  Adopting  the  results  of  recent 
discoveries,  the  following  descriptive  characters  may  be  laid  down. 

Body  bell-shaped  (campaniilate),  supported  on  a  highly  contractile,  un- 
branched  pedicle  or  stem,  and  surmounted  at  its  wide  upper  extremity  by  a 
dilated  and  somewhat  everted  margin,  or  ''  peristom."  The  wide  anterior 
extremity  is  closed  by  a  "  disc,"  fringed  with  cilia,  which  commence  on  one 
side  of  a  depression  or  fossa  in  the  peristom,  called  the  vestibulum,  whence 
they  ascend  to  surround  the  chsc,  and  after  continuing  down  its  sides  or 
"  stem,"  enter  the  mouth,  and  thence  return  to  their  starting  point,  thereby 
completing  a  spiral  ciliary  wreath,  or  rotary  apparatus,  which  serves  by  its 
vibrations  to  di-aw  food  inwards  to  the  mouth,  and,  when  the  animal  detaches 
itself,  as  an  organ  of  locomotion.  The  disc  may  be  slightly  elevated  above 
the  peristom,  but  less  so  than  in  other  true  Yorticellina ;  when  so  elevated, 
the  ciliary  apparatus  is  said  to  be  expanded.  On  the  other  hand,  it  may  be 
withdi^awn  under  cover  of  the  peristom,  the  cilia  disappearing  from  view ; 
and  when  more  strongly  contracted,  the  whole  disc  is  so  drawn  mthin  the 
body  that  the  entii^e  appearance  of  the  anterior  extremity  or  head  of  the 
animal  is  lost,  its  ciliary  mechanism  being  so  inverted  that  it  appears  in- 
ternally hke  an  irregular  sigmoid  cavity,  in  which  the  cilia  may  possibly  be 
distinguishable,  whilst  the  peristom  is  itself  completely  closed  in  upon  the 
whole.  In  this  state  of  com])lete  contraction  the  Vorticella  resembles  a  shut 
ovoid  sac.  Except  the  head,  the  rest  of  a  Vorticella  is  destitute  of  cilia. 
The  fossa  lying  between  the  sides  of  the  ciliary  disc  and  the  peristom  is  the 
vestibulum,  into  which  both  the  oral  and  anal  outlets  open,  within  a  very 
short  space  of  one  another.  The  mouth  opens  below  into  a  ciliated  pharynx 
or  oesophagus,  which  is  extended  a  considerable  distance  into  the  interior  as 
a  digestive  tube,  terminating,  it  would  appear,  suddenly  by  an  open  end. 
The  food  received  at  the  mouth  is  transmitted  through  the  oesophagus,  and 
is  formed  at  its  extremity,  with  the  aid  of  water,  into  a  globule  or  vacuole, 
which  is  pushed  onwards  by  the  vis  a  tergo  in  a  circular  course  towards  the 
anal  outlet.  Besides  molecules  and  granules  derived  from  food  (vesicular 
bodies  composed  of  oily  or  other  matters),  there  are  always  present  in  the 
interior  a  round  contractile  vesicle  and  an  elongated  curved  band- like  nucleus, 
often  with  several  minute  clear  spaces  or  nucleoli.  The  vesicle  is  usually 
placed  near  the  lower  end  of  the  digestive  tube,  and  the  curved,  horseshoe- 
shaped  nucleus  lies  across  at  the  posterior  third  of  the  animalcule.  The 
Vorticellce  multiply  by  longitudinal  self-division,  and  by  the  growth  of  gemmas 
from  their  base,  and  propagate  by  the  resolution  of  the  nucleus,  after  encyst- 
ing itself,  into  numerous  Euglena-like  or  Monadiform  beings,  and,  according 
to  Stein,  by  ciliated  embryos  through  the  mediiun  of  a  previous  conversion 
into  Achietfe.  The  new  beings  formed  from  fission  or  gemmation  are  at  iii'st 
in  a  contracted  condition,  and  on  their  detachment  are  found  to  be  furnished 
with  a  posterior  circlet  of  cilia  to  serve  as  a  means  of  locomotion  imtil  they 
.  affix  themselves  and  proceed  to  develope  a  pechcle,  after  which  it  disappears, 
and  the  ordinary  ciliary  wreath  of  the  head  unfolds  itself.  Indeed,  even 
when  these  processes  of  multiplication  are  not  in  operation,  a  Vorticella 
can  detach  itself  and  leave  its  stalk,  or  swim  away  T\dth  its  pedicle  when 
loosened  from  its  hold. 

The  pedicle  is  remarkably  contractile,  (bawing  itself  into  a  close  coil  with 
extraordinaiy  rapidity,  and  again  uncoiling  itself  with  equal  quickness,  regu- 
lating these  movements  by  external  conditions,  as  though  possessing  con- 
sciousness and  will.  The  pedicle  is  a  hollow  tube,  containing  a  thread  or 
band  within  it,  to  which  its  contractile  power  is  due. 


OF  THE  VORTICELLINA. 


587 


VoRTiCELL  A  nehuliferci  (  V.  nehuUfera  et 
I  V.  ConvaUaria,  M. ) . — Body  campaniilate ; 
j  its  base,  to  whicli  the  pedicle  is  affixed, 
may  be  either  conical  or  hemispherical, 
according  to  its  state  of  expansion  or 
contraction ;  the  pedicle  or  stalk  is  about 
five  times  the  length  of  the  body,  and 
can  fomi  as  many  as  ten  coils.  These 
creatures  usually  congi-egate  together, — 
though  each  is  independent  of  its  neigh- 
bour J  for  on  the  approach  of  any  foreign 
body  to  one,  it  withdraws,  by  coiling  up 
its  pedicle,  while  the  others  remain 
stretched  out  in  search  of  food.  An  am- 
plification of  300  diameters  is  necessary 
to  exhibit  the  cilia.  During  longitudinal 
self-division  the  body  becomes  broader : 
gemmation  takes  place  from  one  or  other 
side,  close  to  the  insertion  of  the  pedicle. 
Abundant,  appearing  like  a  white  film, 
on  the  stalks  and  roots  of  Lemnse  and 
other  water-plants,  even  in  winter  under 
ice.     1-570"  to  1-280"- 

This  is  one  of  the  species  of  Vorticella 
in  which  Stein  believed  he  proved  the 
development  of  an  Acineta  from  the 
encysted  animal,  and  also,  under  other 
circumstances,  the  generation  of  a  brood 
of  young  Monadiform  beings  or  germs. 
I  V.  citrina  (M.). — More  hemispherical 

!  than  the  preceding,  and  the  frontal  mar- 
gin more  expanded.  Upon  Lenmae, 
rarelv  ^vith  the  former  species.  1-430" 
to  1-210";  stalk  3  to  4  times  that  leno-th. 

Perty  speaks  of  this  species  as  having 
a  stifi'  stem,  and  apparently  closely  re- 
lated to  the  genus  Stentor.  Dujardin 
adopts  this  specific  name  for  a  Vorticella 
defined  as  being  very  variable  in  form, 
often  campanulate,  rarely  conical,  having 
a  wide  projecting  border,  variously  con- 
torted or  irregular. 

V.  microstoma  (xx'^^I.  1-6). — Whitish 
grey,  ovate,  narrower  at  the  ends ;  frontal 
margin  not  expanded  or  campanulate ; 
during  contraction  the  animal  is  annu- 
lated;  multiplies  by  longitudinal  and 
transverse  (?)  self-division,  and  by  gem- 
mation. In  stagnant  water.  1-2300"  to 
1-240";  stalk  six  times  longer  than  the 
body. 

This  species  was  the  subject  of  the 
minutest  investigations  by  Stein,  who 
not  only  represented  it  as  becoming 
encysted,  but  also  as  being  either  trans- 
formed mto  an  Acineta  or  Actinophnjs, 
from  which  a  ciliated  embryo  is  deve- 
loped, or  as  giving  origin,  Tvdthout  such  a 
metamorphosis,  to  a  multitude  of  germs. 
He  remarks  on  the  immense  range  of  size 
seen  among  difterent  examples  of  this 
animalcule,  viz.  from  1-300"  to  1-3600" 


(xxvii.  5),  the  smallest  equally  with  the 
largest  exhibiting  the  same  structure. 
The  figure  he  describes  as  pear-shaped, 
the  anterior  half  contracted ;  the  ciliated 
disc  slightly  everted,  not  campanulate; 
rotary  organ  small,  and  elevated  but 
slightly  above  the  periston!.  He  objects 
to  Dujardin's  union  of  this  species  with 
V.  convaUaria,  under  the  name  of  V.  in- 
fusiomim,  as  erroneous,  the  two  being 
perfectly  distinct  beings. 

V.  Canipamda  {Vorticella  lunaris,  M.) 
(xxix.  1). — Hemispherical,  not  annu- 
lated,  bell-shaped,  with  the  frontal  mar- 
gin broad,  truncated,  and  not  expanded. 
Colour  whitish-brown.  This  species  ap- 
pears like  a  thick  bluish  film  upon 
water-plants,  and  the  single  animalcides 
are  discoverable  mth  the  naked  eye. 
1-120" ;  stalk  seven  times  longer  than 
the  body. 

Perty  adopts  MuUer's  name  V.  lunaris 
for  a  species  which  he  considers  equiva- 
lent both  to  V.  Campanula  and  V. patellina. 

V.  hauiata,  —  Small,  ovate,  hyaline, 
attenuate  at  both  ends ;  body  obliquely 
attached  to  the  pedicle.     1-570". 

V.  chlorostigma  (  Vorticella  fasciculata, 
M.). — Green,  ovate,  conical,  campanu- 
late, and  annidated ;  frontal  margin 
(periston!)  expanded.  Oftei!  covers 
grasses  and  rushes  with  a  beautiful 
green  layer.  1-240";  stalk  five  times 
the  length  of  the  body. 

V.  patellina  (M.).  —  Hemispherical, 
campanulate ;  frontal  portion  very  much 
dilated ;  its  i!!argin  greatly  expanded,  and 
often  turned  backwards.  1-480";  stalk 
about  seven  times  the  length  of  the  body. 

V.  convallaria  (  V,  crater  if  or  mis,  citrina, 
gemella,  glohularia,  hilaris,  ?iasuta  et  trtin- 
catella ;  Enchelys  Fritillus ;  Trichoda  gy- 
rinus,  M.). — Ovate,  conical,  campanidate, 
annulated ;  hyaline  or  whitish ;  froi!tal 
portion  dilated,  its  margin  slightly  ex- 
panded. This  appears  to  have  been  the 
first  infusorial  animalcule  discovered. 
Leeuwenhoek,  the  discoverer,  found  it 
in  stagnant  rain-water,  at  Delft,  in  April 
1675.  It  occurs  in  considerable  abim- 
dai!ce  upoi!  the  sui-face  of  vegetable  in- 
fusions, with  V.  microstoma,  from  which 
it  is  distinguished  by  its  broad  froi!t, 
which  gives  to  it  a  beU-shaped  or  cam- 
panulate appearance.  Cams,  in  1823, 
fancifully  represented  it  as  arising  from 
spontaneous  generatioi!  in  oil,  or  froi!! 
an  accidental  mixture  of  oil  colom*  and 
sprii!g-water.  It  has  been  described 
under  various  names  by  different  natu- 
ralists. 1-430"  to  1-24" ;  stalk  six  tii!!es 
its  lenofth. 


588 


SYSTEMATIC  HISTORY  OF  THE  INFrSORIA. 


This  well-known  animalcule  is  usually  I  out  its  length  with  red  dots.  1-1150"  to 
found  attached  to  extraneous  bodies  in  !  1-570"  j  stalk  foiu"  to  five  times  as  long, 
water ;  such  as  the  leaves  of  duck-weed,  j  Perty  treats  V.  lunaris,  V.  faseiculata, 
small  aquatic  shells,  clusters  of  the  ova,  j  and  V.  cirrata  of  Miiller  as  distinct 
or  the  larv£e  of  insects ;  an  example  of  j  species,  instead  of  accepting  them  as 
the  latter  is  shown  in  the  Microscopic  varieties  of  others  named  by  Ehrenberg- ; 
lUmtrations,  fig.  .30,  where  it  may  be 
considered  as  a  parasite,  or  rather  an 
epiphyte.  As,  when  fully  developed, 
it  is  mostly  attached  to  some  sta- 
tionary object,  it  affords  many  facilities 
to  the  microscopist  for  observation,  and 
forms  a  good  object  also  for  ascertaining 
the  defining  power  of  his  instrument, 
and  his  expertness  in  its  management; 
for  much  of  the  clearness  in  structure 
will  depend  on  the  manner  in  which  he 
manages  the  illumination.  If  this  be  not 
attended  to,  and  the  instrument  has  not 
sufficient  power  and  penetration,  it  will 
exhibit  only  two  cilia  instead  of  a  cir- 
cular row;  indeed  this  animalcule  is 
described  and  draA\Ti  in  this  manner  by 
the  old  authors, — an  error  which  recent 
improvements  in  the  microscope  have 
demonstrated. 

\.picta. — Ovate,  conical,  campanulate ; 
frontal  portion  dilated,  and  its  margin 
slightly  expanded.  The  pedicle  is  veiy 
slender,  and  cmiously  marked  through- 
Genus  CAECHESIUM  (XXX.  9) 
genus  by  the  spirally  flexible  branched  pedicle.  The  bodies  (zooids)  upon 
the  pedicle  are  all  of  the  same  form.  The  organization  of  this  genus  is  not 
so  well  known  as  that  of  VorticeUa  and  Ejjistylis.  There  is  a  simple  wreath 
of  cilia,  which  duiing  quick  vibration  appears  double ;  and,  as  in  VorticeUa^ 
a  posterior  circlet  is  produced  at  certain  periods ;  within  the  pedicle  a  trans- 
versely folded  contractile  band  is  observed  during  contraction.  The  mouth 
is  lateral.  Internally  are  whitish  granules,  and  a  contractile  bladder ;  but 
the  nucleus  is  indistinct.  The  gTo^i;h  of  gemmae  has  been  observed ;  and 
the  zooids  can  detach  themselves  from  the  stalk,  as  in  the  case  of  VorticeUa. 
One  of  the  best  distinctive  features  between  Carchesium  and  Zoothamnium, 
is  that  the  contractile  band  of  the  former  is  not  continuous  throughout  the 
pedicle  and  its  branches  as  it  is  in  the  latter  (see  p.  293).  This  is  noticed 
both  by  Stein  and  Dr.  Wright :  the  latter  adds,  "  The  division  of  the  zooids 
is  more  complete  in  Carchesium  than  in  Zooihamnium.  In  the  former,  at 
each  division,  one  of  the  zooids  produces  a  new  muscle  not  connected  with 
that  of  the  zooid  from  which  it  has  separated." 

Carchesium  pohjpinum  (Leeuwen-  I  C.  pygmxBum  {Zoothamnium  Parasita, 
hoek)  {V.  poly])ina,  M.  and  Duj.)  (xxx.  |  Steiu). — Very  small,  ovate,  white,  rather 
9). — Conical,  campanulate,  white  ;  the  i  dilated  in  front ;  pedicle  branched  in  a 
frontal  portion  broad,  trmicate,  and  its  I  bifid,  rarely  in  a  trifid  manner.  1-2400''. 
margin  expanded ;  pedicle  branched  in  a  |  Berlin.  On  Cyclops  quadricornis. 
sub-umbellate  manner.  The  axis  matter  C.  spectahile.  —  Conical,  campanidate, 
or  supposed  muscle  of  the  pedicle,  first  dilated  in  front ;  branching  in  an  oblique 
observed  bv  Mr.  Varley,  is  very  distinct.  |  conical  poh^ary,  attaining  two  lines  in 
1-570"  to  i-430".  1  height.     Berlin. 

Genus  EPISTYLIS  (XXVII.  16, 22, 23 ;  XXX.  11).— Pedicle  rigid,  either 
simple  or  branched  ;  all  the  zooids  of  the  same  figure ;  or,  in  other  words. 


but  he  fails  to  give  the  characteristics 
necessary  to  their  establishment  as  such. 
It  is  to  be  remarked,  however,  that  V. 
hmaris  and  V.  faseiculata  are,  he  is  in- 
clined to  believe,  merely  varieties  of  the 
same  species. 

VorticeUa  Ampulla  (MiiUer)  is  treated 
by  Lachmann  as  the  representative  of  a 
new  genus,  as  yet  unnamed,  belonging 
to  the  Stentorinae  (A.  N.  H.  1857,  xix. 
p.  128). 

V.  infusionmn  (Duj.)  is  not  equivalent 
to  V.  microstoma  and  V.  Convallaria,  as  he 
represented  it  to  be.  He  describes  it  as 
commonly  ovoid  or  nearly  globular,  trmi- 
cated  at  the  head,  wdth  a  slightly  pro- 
jecting border.  The  pedicle  is  very 
flexible,  its  surface  striated  obliquely. 

V.  ramosissima  (Duj.)  =  Carchesium 
polypinum  (Ehr.). 

V.  Arhuscula  (Duj.)  =  Zoothamnium 
Arhuscula  (Ehr,). 

V.  lunaris  (Duj.)=  V.  Campanula  and 
V.  patellina  (Ehr.), 

Distinguished  from   the   preceding 


OF  THE  TORTICELLIJTA.  589 

they  are  Vortkellce  or  Carchesia  with  a  rigid  hollow  pedicle,  without  an 
internal  contractile  band.  The  situation  of  the  mouth  and  anal  opening  is 
easily  demonstrated  by  the  employment  of  coloured  food.  In  E.  pJicatilis,  says 
Ehi'enberg,  the  whole  coiu-se  of  the  ahmentary  canal  can  be  seen.  A  con- 
tractile sac  and  a  short  band-like  nucleus  are  observable  in  many  ;  the  latter, 
however,  is  spherical  in  E.  nutans.  Longitudinal  self-division  and  gemmation 
frequently  seen.  The  Epistylides  are  among  the  largest  of  the  Yorticellina, 
and  are  exclusively  found  in  pure  water,  on  aquatic  plants  or  animals. 

Stein's  researches  throw  additional  light  on  the  structure  of  EpistyliSj 
which,  he  says,  resembles  generally  that  of  Vorticella.  The  body  has  usually 
an  ovoid  or  almost  spindle-shaped  figm^e,  truncate  in  front,  where  a  slightly 
everted  ciHated  peristom,  of  a  sphincter-  or  lip-like  character  surrounds  it,  and 
gives  to  the  whole  being  somewhat  of  a  bell-shape.  AVithin  the  peristom  is  a 
ciliary  disc  capable  of  being  protnided  or  retracted  at  the  pleasiu-e  of  the 
animal,  and  having  on  one  side  the  oral  apertui-e.  This  disc  is  the  '*  rotary 
organ  "  in  Stein's  description,  and  in  EpistyJis  its  pedicle  or  stem  is  always 
short  and  thick.  ^Tien  retracted,  the  sphincter-Kke  peristom  closes  over  the 
rotary  organ  like  a  lid,  and  then  the  whole  animal  acquires  a  pear-shaped  or 
globiilar  fig-ure.  ^\Tien  the  contraction  has  proceeded  to  its  utmost,  the 
peristom  appears  like  a  wedge-shaped  or  cylindrical  process  surmounting  the 
body.  The  mouth  opens  into  a  slightly  coiled,  tapering  tube,  which  ends 
abruptly  towards  the  centre  of  the  body ;  near  its  tennination  is  a  contractile 
vesicle,  and  not  far  from  the  last  an  elongated  band-like  or  reniform  nucleus. 
EpistyJis  multiplies  in  precisely  the  same  manner  as  Vorticella,  by  fission 
and  gemmation.  Stein  believes  he  has  traced  a  cycle  of  changes  through 
which  it  passes,  between  the  encysted  condition  on  the  one  hand,  and  the 
development  of  a  ciliated  TnchocUna-]ike  embryo  from  an  Acinetiform  phase 
of  existence  on  the  other.  His  observations  tend  to  show  that  the  embryonic 
being  developed  from  the  Acineta  of  Epistylis  anastatica  is  similar  to  Tnclwdina 
G-randinella  (Ehr.),  and  probably  identical  with  it.  In  E.  nutans  he  satisfied 
himself  of  the  occurrence  of  similar  transformations,  but  felt  less  assm^ed  of 
their  occurrence  in  E.  grandis,  E.  herherifomnis,  E.  Barha,  and  E.  p)licatilis. 

The  stem  or  pedicle  is  inflexible.  No  canal,  as  represented  by  Ehrenberg,  is 
usually  discoverable ;  but  sometimes  the  stem  is  finely  striated  longitudinally, 
and  in  older  specimens  has  at  valuing  distances  transvei-se  lines  or  false  joints. 
Dujardin  proposed  to  amalgamate  the  two  genera  Epistylis  and  Opercularia, 
since  he  could  distinguish  no  generic  differences  between  them.  In  this  pro- 
posal, however,  he  was  wi^ong,  for,  as  Stein  shows,  there  are  sufficient  di- 
stinctive peculiarities  to  warrant  their  generic  independence.  (See  description 
of  Opeeculaeia.)  The  animals  seated  on  its  branches,  by  their  mode  of 
articulation,  enjoy  considerable  latitude  of  motion,  and  are  also  able  in  some 
degree  to  shorten  themselves  by  the  annular  segments  of  theii'  base. 

The  stem  is  secreted  by  the  animalcules  it  supports.  When  fission  has  taken 
place,  two  beings  are  for  a  time  seen  seated  at  the  extremity  of  the  same 
pedicle  ;  but  soon  each  begins  to  produce  from  its  attached  base  a  new  pedicle 
for  itself,  and  thus  the  original  stem  becomes  branched,  and  this  in  a  fiu'cate 
or  dichotomous  manner. 

All  the  members  of  the  same  little  tree  (polypidom)  are  of  nearly  equal 
size.  In  the  case  of  E.  nutans,  the  largest  noticed  were  l-20th  of  a  line  in 
length  ;  whilst  in  other  polypidoms,  whose  stems  and  branches  were  propor- 
tionately thinner,  examples  were  met  with  of  very  minute  size  (XXYII.  22, 
23).  In  the  smallest,  no  anterior  cilia  and  no  contained  globules  were 
visible  ;  in  larger  ones,  though  only  l-loOth  of  a  line  in  length  (XXYII.  23), 
such  were  found.     These  latter  fonns  constitute  Epistylis  Botrytis  (Ehr.). 


590 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Epistylis  Galea.  —  Large,  conical, 
contractile  by  transverse  folds;  mouth 
lateral  and  ]3rojecting;  pedicle  thick, 
branched,  and  articulated.  Upon  Cera- 
tophijUum.     1-120". 

E.  anastatica  (  V.  anastatica,  craicsc/aria 
et  ringens,  M.). — Oval,  without  folds; 
frontal  margin  dilated  and  projecting; 
pedicle  dichotomous,  smooth — or  squa- 
mous with  foreign  particles.  The  gra- 
nules are  white  by  reflected,  and  yel- 
lowish by  transmitted  light:  the  clear 
vesicle  is  often  to  be  seen,  but  not  its 
contraction;  growth  of  gemmae  un- 
known ;  self-division  longitudinal. 
Upon  Ceratophi/llum  and  small  aquatic 
Mollusca  and  Entomostraca.  1-280"; 
height  of  little  tree  1-140". 

'' JE.  anastatica,''''  says  Stein,  "  diiFers 
from  E.  I)iffitalis,w]uch.  it  very  closely  re- 
sembles, by  the  form  of  its  body,  which  is 
always  funnel-shaped  and  campanulate, 
like  that  of  E.  pUcatilis,  only  less  elon- 
gated, and  by  the  branches  of  its  stem 
being  outspread  in  a  fan-like  manner 
and  acquiring  a  nearly  equal  height,  or 
an  umbellate  condition."  He  adds,  "■  The 
three  species  most  nearly  allied,  viz.  E. 
anastatica,  E.  pUcatilis,  and  E.  Digitalis, 
have,  when  studied  at  different  ages,  few 
points  of  separation,  except  that  furnished 
by  their  habitats, — E.  pUcatilis  living 
upon  the  shells  of  Mollusca;  E.  anas- 
tatica upon  the  roots  of  Lemna  ;  and  E. 
Digitalis  upon  Cgclops  quadricornisy 

E.  pUcatilis  (  V.  annularis  et  pgraria, 
M.). — Conical  and  elongated,  contractile 
in  annular  folds ;  frontal  margin  dilated, 
trimcated,  and  slightly  projecting; 
pedicle  dichotomous,  often  corpnbose, 
smooth,  or,  when  foreign  bodies  adhere, 
of  a  scaly  appearance.  This  species  is 
white  to  the  naked  eye,  but  somewhat 
yeUow  beneath  the  microscope ;  it  is 
very  much  like  the  preceding,  is  often 
found  with  it,  but  is  distinguished  by 
being  larger,  by  its  ring-like  folds  when 
contracted,  and  by  the  tasselled  or  tufted 
appearance  of  the  cluster.  1-280"  to 
1-210". 

The  stem,  says  Stein,  is  solid  and 
longitudinally  striped.  The  nucleus  is 
reniform,  and  the  contractile  vesicle  lies 
within  the  substance  of  the  large  rotary 
organ.  In  old  stems  transverse  lines  or 
joints  appear,  at  a  distance  from  one 
another.  The  largest  examples  Stein 
met  %vith  were  1-168"  in  length. 

E.  grandis.  —  Broadly  campanulate, 
stalk  decumbent,  slender,  smooth;  the 
branches  flexible  and  without  articula- 
tions, but  much  tufted.     This  is  not  onlv 


the  largest  freshwater  species  of  Epi- 
stglis,  but  it  also  forms  the  greatest 
masses.  Its  proper  colour  is  a  bluish 
white  ;  but  it  often  appears  of  a  yellow  or 
greenish  hue,  from  the  colour  of  its  food. 
Upon  Ceratophgllum  and  Ngmphcea, 
often  like  a  bluish- white  slime,  easily 
broken  up.  In  masses  several  feet  long, 
and  two  to  three  inches  thick.  1-140"  to 
1-120". 

E.  Jlavicans  (  V.  acinosa  et  hellis,  M.). 
—  Large,  broadly  campanulate,  and  of 
a  yellow  colour;  pedicle  smooth,  its 
branches  coarctate.  The  branches  are 
dilated  at  the  axillae.  In  this  species  the 
alimentary  canal  is  very  evident.  Size 
(stretched  out)  1-190";'  tree  1-9"  high. 

Although  Stein  represents  the  stem 
in  Epistglis  to  be,  as  a  rule,  solid,  yet,  in 
a  passing  notice  (p.  72)  of  E.  JiavicanSj 
he  remarks  that  the  pedicle  evidently 
had  a  hollow  central  canal. 

E.  leucoa  ( Volvox  SphiBnda,  M.).  — 
Large,  broadly  campanulate ;  pedicle 
erect,  smooth,  and  articulated;  the 
branches  capitate  or  collected  in  a  head. 
These  animalcules  are  convex  anteriorly, 
have  distinct  colourless  granules,  a  sim- 
ple ^vl'eath  of  cilia,  and  a  round  mouth  on 
the  margin.  The  nucleus  is  bent  in  the 
form  of  the  letter  S.  ^  1-120" ;_  tree  1-24". 

E.  Digitalis  (  F.  Digitalis,  ringens  et  m- 
clinans,  M.). — Small,  cylindrical,  campa- 
nulate; stem  dichotomous,  and  finely 
annulated.  This  weU-marked  fonn  in- 
fests the  Cyclops  quadricornis,  which  it 
sometimes  completely  covers.  In  the 
beautifid  little  tree  this  species  fomis  by 
its  branching",  the  Notommata petroniyzon 
nestles  just  like  a  bird  in  a  bush,  and 
fastens  its  eggs  to  its  branches.  Coloured 
food  is  readily  taken.  1-430" ;  tree  1-20". 

The  figure  is  more  like  that  of  the 
flower  of  the  foxglove  (^Digitalis),  as  the 
name  implies,  than  bell-shaped ;  for  the 
peristom  is  very  little  everted,  and  its 
diameter  not  greater  than  the  middle  of 
the  body.  The  rotary  organ  protrudes 
some  distance,  and  lies  very  obliquelv. 
The  nucleus  is  band-like,  and  cm-ved  in 
a  semicircle.  The  annulation  of  the 
stem  could  not  be  seen  by  Stein,  except, 
as  in  very  many  Epistgl ides,  near  the  jimc- 
tion  or  'bifm-cation  of  the  branches,  and 
occasionally  in  very  old  specimens  :  in 
these  last  it  often  has  a  rusty  colour. 

E.  (?)  mdans  {Opercularia  nutans, 
Stein).  —  Ovate,  attenuated  at  both 
ends ;  mouth  two-lipped  and  prominent. 
The  pedicle  annulated  (xxvn.  16,  22, 
23).  "This  animalcule,"  says  Ehren- 
berg,  "can  push  forth  a  bladder  between 


OF  THE  VORTICELLINA. 


591 


its  lips,  like  (si  parva  licet  componere 
magnis)  a  camel  can  its  palate".  1-430" ; 
tree  1-24". 

The  process  above  alluded  to  by 
Ehrenberg  as  protruded  from  the  head 
of  this  animal  is  undoubtedly  the  sort  of 
under  lip  alluded  to  b}'  Stein  in  his  ac- 
count of  Opercular ia  (see  next  page). 
This  author,  again,  confirms  Ehrenberg  in 
his  doubt  as  to  the  position  of  this  species, 
and  shows  that  it  is  an  Opcrcularia. 

^.Botri/tis. — Verysmall,oyate,crowned 
■v\-ith  cilia.  They  resemble  grapes  upon 
a  simple  hyaline  pedicle.  This  species 
together  with  E.  Arabica  and  Carchesimn 
pygmceum  are,  in  Stein's  opinion,  not 
really  distinct  species,  but  difi'erent 
phases  of  the  same  animalcule.  1-2400"; 
tree  1-240"  (see  p.  589,  last  line). 

E.  vegetans  ( Volvox  vegetans,  M.).  — 
Very  smaU,  oyate,  crowned  with  cilia 
(?) ;  disposed  in  clusters,  like  the  pre- 
ceding, upon  a  branched  pedicle,  of  a 
yeUow  colour.  When  the  water  con- 
taining this  species  is  coloured  with 
indigo,  strong  cm-rents  are  seen  at  the 
front  or  head  of  each  animalcule,  evi- 
dently caused  by  a  yibratile  organ ;  but 
whether  this  is  a  ^i-eath  of  cilia  or  a 
simple  proboscis,  is  undetermined ;  if  a 
proboscis,  this  creature  would  belong  to 
the  Monads,  where  it  would  form  the 
type  of  a  new  genus.  In  river-water. 
i-'Sm" ;  tree  1-140". 

Brightwell  says  (Fauna  Infusoria  of 
Norfolk,  1848)  that  the  armed  or  oval  ani- 
malcules are  furnished  with  a  long  fila- 
ment, that,  when  the  M^ater  is  shallow, 
they  detach  themselves,  and  swim  about 
with  a  revolving  motion.  The  organ  of 
motion  he  states  to  be  a  long  filament 
(proboscis)  ;  if  so,  the  animal  is  not  an 
EpistyUs.  Stein  treats  it  also  as  a  very 
doubtful  Ejnstylis. 

E.  parasitica. — Small,  conical,  campa- 
nulate,  and  solitary  ;  pedicle  simple  and 
smooth.  Upon  Zoobotryon  pellucidus. 
1-570" ;  with  pedicle  1-120"  to  1-24". 

E.  Arabica.  —  Small,  oval,  campanu- 
late ;  pedicle  but  little  branched,  smooth, 
and  hyaline.  In  the  Red  Sea.  Size  of 
tree  1-140". 

This  species,  as  well  as  E.  Botrytis  and 
Carchesium  pygmceum,  are  adduced  by 
Stein  as  insufficiently  marked,  and  re- 
fen-ed  by  him  to  the  yoimg  and  incom- 
plete forms  of  other  species. 

E.  Barba.  —  Ovate,  oblong,  white ; 
branches  dichotomous ;  longitudinally  and 
regularly  striated.     On  larvfe  of  insects. 

E.  beiberiformis-=  Opercnlaria  berbe- 
rina    (Stein)   (xxix.  4).  —  Oblong,    sub- 


cylindrical,  white ;  stem  dichotomous, 
articidated,  and  striated,  its  divisions 
dilated  at  their  apices.  Parasitic,  Berlin. 

This  is  not,  as  Stein  shows,  a  species 
of  Epistylis,  but  of  Ojjercularia,  under 
which  we  shall  introduce  it  ^dth  the  de- 
scriptive account  this  able  writer  supplies. 

E.  euchlora. — Oblong,  rather  expanded 
in  front,  with  green  ova ;  stem  dichoto- 
mous. 1-13"  in  height,  smooth.  Para- 
sitic on  Planorbis  cornea,  Berlin. 

E.  pavonina.  —  Ver}-  large,  helmet- 
shaped,  elongated  in  front;  stem  very 
high,  dichotomous,  striated,  and  hence, 
by  decomposing  light,  displays  many 
hues.     Often  1-3"  in  height.     Berlin. 

E.  crassicollis  (Stein)  (xxx.  11). — 
Stem  of  considerable  height,  acutely  and 
dichotomously  branched  so  that  the  seve- 
ral zooids  it  supports  are  brought  nearly 
on  the  same  level  (corymbose).  Branches 
smooth,  transparent,  straight,  and  of 
equal  thickness.  In  some  specimens 
transverse  lines  or  joints  occur;  and  the 
stem  is  frequently  dilated  at  the  point 
of  divergence  of  its  branches.  Animal- 
cules ovate,  contracted  posteriorly,  and 
also  in  a  slighter  degree  anteriorlj'.  The 
annulated,  hoop-like  periston!  surmounts 
the  body,  ha^-ing  a  rather  smaller  dia- 
meter. The  rotary  disc  is  convex,  but 
rises  only  slightly  above  the  periston!. 
The  cesophagus  and  its  intestine-like 
continuation  curve  backward  almost  to 
the  posterior  extremity  of  the  body. 
The  contractile  space  lies  close  to  the 
lower  end  of  the  stem  of  the  rotary 
organ ;  the  nucleus  is  hoi^seshoe-shaped. 
Contents  white,  frequently  with  specks 
of  red.  Largest  specii!!ens  1-240"  in 
length,  and  1-480"  in  width.  Occurs  on 
the  bristles  ^of  the  hind  feet  and  of  the 
jaws  of  Entomostraca. 

E,  brancliiophila  (Perty).  —  Spherical, 
with  a  truncate  base ;  colour  grey.  Stem 
and  branches  colourless  and  smooth. 
1-360";  length  of  polypidom  1-96".  The 
animalcules  are  sparse  in  reference  to  the 
dimensions  of  the  steii! :  the  latter  often 
rugose  at  its  jimction  with  the  animal  it 
suppoii;s.  When  the  stem  coi!tracts  it 
does  so  only  on  oi!e  side,  and  not  com- 
pletely across.  Both  this  desciiption 
and  the  figures  given  in  illustration  by 
Perty  are,  as  Stein  observes,  insufficient 
to  characterize  the  species.  The  latter 
writer  retains  the  name,  however,  for  an 
Epistylis  having  a  relatively  thick  stem, 
of  moderate  height,  repeatedly  forked, 
finely  striated  and  somewhat  curved.  Of 
the  two  branches  resulting  froi!!  a  bifur- 
cation, one  attains  a  much  greater  length 


592 


SYSTEMATIC  HISTORY  OF  THE  IXFI'SOEIA. 


than  the  other ;  hence  the  appearance  of 
a  main  stem  and  a  subsidiary  branch. 
The  zooids  terminating  the  ramifica- 
tions are  pear-shaped,  the  ^\^dth  nearly 
equalling  the  length,  and  almost  glo- 
bular when  the  periston!  is  contracted. 
They  are  of  a  greyish  hue.  The  rounded, 
lip-like,  ciliated  periston!  is  of  less  dia- 
meter than  the  widest  part  of  the  body  ; 


and  its  entire  space  is  occupied  by  the 
rotary  organ,  which  is  only  a  little  ele- 
vated above  it  when  extended.  The 
nucleus  is  elongated  and  veri!!icular. 
The  average  lei!gth  of  the  bodv  is  1-360" 
to  1-280"'-  and  the  width  "1-456"  to 
1-336".  Geiiimation  may  be  frequently 
seen,  the  buds  growing  fi'om  the  fore 
part  of  the  body  behind  the  peristom. 


Genus  OPEECULARIA  (XXIX.  4;  XXX.  1,  2,  27).~Branched  pedicle, 
stiff  and  rigid,  supporting  dissimilar  corpuscles  (zooids).  The  anamalcules 
have  two  lips ;  the  superior  one,  supported  by  a  muscle,  is  somewhat  like  a 
lid  (operculum),  which  is  a  characteristic.  Operculana  =  Epistylis  with  dis- 
similar corpuscles.  The  organs  of  locomotion  consist  of  a  wreath  of  cilia, 
and  a  long  muscle  within  the  body  ;  this  raises  or  depresses  the  frontal  region, 
in  the  form  of  an  upper  lip.  Food  is  taken  into,  and  its  effete  portions  dis- 
charged from  the  large  vestibulum  situated  in  front  and  rather  to  one  side, 
and  to  and  from  which  the  alimentary  canal  is  seen  running.  Self-division 
and  the  separation  of  the  zooids  from  the  stalk  may  be  frequently  observed. 
The  large  dissimilar  bodies  occur  singly  beneath  the  animalcules,  more  espe- 
cially in  the  axillae  of  the  branches ;  some  are  very  large  and  egg-shaped, 
with  hairs  at  their  point,  and  only  a  small,  round,  non-vibratile  opening. 
Ehrenberg  observes  that  such  are  most  probably  parasitic  bodies.  In  all 
probability,  however,  they  are  encysted  corpuscles. 

The  following  characters,  contrasted  with  those  of  Epistiflis,  are  given  by 
Stein.  The  peristom  is,  in  Opercidcn^ia,  merely  a  single  border,  neither 
ciliated,  thickened,  nor  everted  in  a  campanulate  manner.  The  body,  there- 
fore, is  elongated,  ovoid,  constantly  narrowed  anteriorly,  and  simply  ti^uncated. 
The  opening  of  the  peristom,  which  also  forms  that  of  the  mouth,  extends  as 
a  mde  and  deep  cavity  (the  vestibulum)  to  the  oesophagus,  which  is  prolonged 
far  into  the  body  as  a  narrow  digestive  tube.  A  distinction  between  this  last 
canal  and  the  oesophagus  is  indicated  by  a  group  of  three  or  four  strong  cilia 
placed  at  its  commencement.  The  rotary  organ  springs  from  the  wide  oral 
cavity,  on  one  side,  by  a  narrow  point,  which  is  the  apex  of  its  trumpet- 
shaped  figure.  The  base  of  this  long  conical  sac  is  formed  by  its  ciliated  disc, 
which  is  thrust  much  above  the  peristom  when  extended,  but  can  be  drawn 
down  upon  it  and  close  it :  the  whole  organ  is  very  moveable.  The  older 
observers  looked  upon  the  rotary  organ  as  a  valve  or  lid ;  and  Ehrenberg 
supposed  it  to  have  a  long  retractile  muscle  which  could  close  it  upon  the 
mouth.  However,  no  muscle  exists  within  the  pedicle  of  the  organ  ;  for  this  is 
a  hollow  sac  fiUed  with  the  same  substance  as  the  general  cavity  of  the  body, 
and  in  direct  communication  with  it.  The  pedicle  of  the  ciliary  disc  is  longer 
and  more  moveable  than  that  of  VorticeUa  and  Epistylis.  The  genus  Opercu- 
laria  is  fui'ther  distinguished  by  the  presence  of  a  delicate  membranous,  trans- 
parent process  which  stands  out  from  the  throat  like  an  internal^  fixed  colfar, 
and  is  elevated  above  the  peristom,  forming  a  sort  of  under  lip  to  the  rotary 
organ.  Whether  this  is  ciliated,  or  onlj^  a  vibrating  membrane,  Stein  remains  in 
doubt.  It  is  the  same  structure  as  is  referred  to  by  Ehrenberg  in  his  note  on 
Epistylis  ?  (  Opercularid)  nutans  as  a  protrusile  bladder-like  process  (see  p.  590). 


Opercularia  articulata  (V.  Ojoercu- 
laria,  M.)  (xxx.  1)  occm's  as  a  little 
shrub,  1-6"  to  1-4"  high,  white  and 
dichotomous ;  carmine  and  indigo  readily 
states  he  saw  as 


taken  ;  and  Ehrenbei 


many  as  forty-four  stomach-cells  filled, 
resembling  a  girdle  in  the  middle  of  the 
body.  The  stalk  is  very  delicately 
striated  in  a  longitudinal  direction,  and 
shows,  at  its  ramifications,  a  transverse 


OF  THE  YOETICELLmA. 


593 


line,  or  joint.  Upon  Dytiscus  marginalis. 
1-430". 

Stein  creates  several  additional  species 
of  Opercidaria,  and  has  entered  into  many 
details  respecting  the  structure  of  O.  ar- 
ticulata  (xxx.  1,  2j.  According  to  him, 
the  body  is  spindle-shaped  or  ovate-elon- 
gate, and  truncate  before  and  behind. 
The  periston!,  which  is  continuous  with 
the  body,  forms  a  simple  terminal  edge, 
sometimes  quite  smooth,  at  others  plaited 
longitudinally.  Similar  plaits  often  occur 
at  its  posterior  half,  when  the  animalcule 
contracts  itself.  The  disc  of  the  rotary 
organ  has  three  circlets  of  cilia,  is  con- 
tractile and  changeable  in  form.  The 
oral  ca-vity  behind  the  margin  of  the 
peristom  is  very  wide  and  deep,  ex- 
panded as  a  capacious  sac,  from  one 
comer  of  which,  posteriorly,  the  digestive 
tube  proceeds.  It  is  lined  internally  by  a 
delicate  hyaline  membrane,  which  pro- 
jects beyond  the  peristom  like  an  upright 
collar.  At  the  base  of  the  body  is  a  dense 
collection  of  granules,  apparently  of  a 
fatty  character.  The  nucleus  is  horse- 
shoe-shaped, and  a  round  contractile 
space  lies  near  to  the  digestive  tube  at 
its  commencement.  There  is  a  pecu- 
liar glandular-looking  body  on  each  side 
of  the  oral  cavity  at  the  anterior  part  of 
the  body,  the  natm^e  of  which  is  not  de- 
tennined.  When  in  a  state  of  contrac- 
tion the  animal  is  thrown  into  annular 
folds,  the  rotary  organ  completely  re- 
tracted, and  the  periston!  closed  over  it 
in  a  sphincter-like  manner,  the  whole 
body  assui!!ing  a  spindle-shaped  foiii!, 
or,  when  cont!-acted  to  the  uti!iost,  a 
pmform  or  orbicidar  figure.  Reproduc- 
tion takes  place  by  gemiiiation ;  but  fission 
has  not  been  observed  :  Stein  believes  in 
the  transfo!7nation  of  the  animals  into 
Aeimtce,  and  the  development  froi!! 
these  of  ciliated  gemis  (xxx.  3,  4). 

The  length  of  the  body  of  the  largest 
specimens,  when  extended,  is  1-96"; 
and  the  greatest  ^vddth,  at  the  i!!iddle, 
1-216".  The  steii!  is  very  variously 
branched,  and  is  less  rigid  and  more 
flexible  than  in  other  species.  The 
ti-ausverse  lines  or  false  joints  are  not 
characteristic,  and  the  longit!idinal  stria- 
tion  is  not  always  observable. 

0.  herherina  (Stein)  (xxix.  4)  =  Epi- 
stylis  herheriformis  (Ehr.).— Animalcides 
outstretched  elono^ated,  cylindrical, 
slightly  contracted  before  and  behind  : 
about  2i  times  longer  than  broad,  with- 
out reckoning  the  extruded  rotary  organ. 
No  separable  peristom  exists  at  the  ante- 
rior truncated  extremitv  {i.  e.  in  technical 


phrase,  it  is  obsolete);  rotary  organ 
conrparatively  shortly  stalked,  its  disc 
having  a  single  whorl  of  cilia.  Oral 
cavity  capacious,  as  in  O.  artkidata ;  its 
membranous  lining  mrdulating,  and  seen 
with  difficulty.  An  anal  opening  ap- 
pears at  the  base  of  the  oral  cavity,  not 
far  froi!!  the  orifice  of  the  oesophagus. 
Even  when  expanded,  the  body  is  sur- 
rounded by  thickly-placed  anntilar  folds, 
which  becoi!!e  i!iuch  more  strongly  pro- 
nounced when  it  contracts  itself.*  The 
siu-face  of  the  body  is  covered  by  a  very 
firm,  transparent,  structm-eless  mem- 
brane, which  can  be  isolated  for  exa- 
mination without  any  special  prepara- 
tion, and  is  often  left  behind  after  death 
as  a  distinct  sheath  or  skeleton.  Multi- 
plication by  gemi!!ation  has  not  been 
observed ;  but  fission  is  comi!!on.  The 
largest  specimens  were  1-190"  in  length, 
and  1-570"  in  width. 

The  fori!!  of  the  stem  is  very  variable, 
for  two  similar  specimens  are  scarcely 
to  be  found ;  yet  in  all,  the  animalcules 
are  supported  at  different  heights,  on 
stems  varying  in  length,  and  therefore 
not  corymbose.  The  stem,  likewise,  has 
not  the  stiff,  regular  construction  of 
most  Opercularice  and  Epistylkles,  but  is 
generally  curved  outwards,  and  has  at 
variable  distances  transverse  lines  or 
joints  ;  the  extremity  supporting  the 
animalcule  is  expanded.  It  is  through- 
out solid,  colourless,  and  diaphanous, 
and  if  at  all  striated  longitudinaUy,  is  so 
in  a  very  faint  manner.  On  aquatic 
animals.  Stein  believes  he  has  dis- 
covered its  Acineta  (xxiii.  17,  20). 

0.  LicMensteinii. — Body  stout,  short, 
barrel-like,  the  length  not  being  double 
the  width ;  except  in  sparingly-branched 
stems,  the  opposite  ends  are"  little  con- 
tracted. The  rotary  organ  is  but  slightly 
elevated  above  the  peristoi!! ;  its  stem  is 
short,  thick,  and  al!!!ost  cylindrical,  little 
exceeded  in  width  by  the  disc  surmount- 
ing it,  which  has  but  a  single  circlet  of 
cilia.  The  men!brano!is  process  within 
the  oral  cavity  rises  above  the  peristom, 
is  notched,  thrown  into  longitudinal  folds, 
and,  to  all  appearance,  ciliated.  The 
nucleus  is  always  short  and  oval  or 
round;  its  position  varies;  the  con- 
tractile space  is  circidar,  in  proximity 
to  the  beginning  of  the  digestive  tube 
or  the  oesophagus.  The  heap  of  fatty 
corpuscles  near  the  base  is  present,  as 
in  many  rigid-stem  Vorticellina.  The 
maximum  length  is  1-190" ;  and  the 
width  1-300".  It  differs  from  O.  arti- 
culata  (xxx.  1,  2)  by  its  round  nucleus, 
2q 


594 


SYSTEMATIC  HISTOEY  OF  THE  INFrSORIA. 


and  from  O.  herherina  (xxix.  4),  whicli 
it  closely  resembles  in  its  general  orga- 
nization, by  its  length  and  width  being 
much  nearer  equal,  and  by  its  not  being 
bent  backwards  on  the  stem  when  con- 
tracted. Stein  describes  its  Acineta  and 
the  ciliated  embryo  resulting  from  it. 
The  stem  is  subject  to  great  varieties ; 
but  these  all  agree  in  the  stem  expanding 
from  its  base  in  a  more  or  less  marked 
manner,  in  the  branches  being  all  of  equal 
length,  and,  in  consequence,  the  zooids 
elevated  at  different  heights.  The  stems 
of  the  oldest  generations  are  low,  and 
have  but  few  animalcules  upon  them, 
which  are  seated  on  short,  cun'ed,  and 
enoi-mously  thick  branches,  such  as  are 
seen  in  no  other  OpercularicB.  The 
whole  surface  of  the  stem  is  covered  with 
numerous,  closely-placed,  shallow  and 
deep  transverse  folds  or  constrictions, 
which  give  it  a  Imotty  appearance ;  it  is 
also  longitudinally  striated.  In  younger 
generations  the  stems  are  more  densely 
branched  ;  but  the  branches  are  not  ex- 
traordinarily thickened,  being  as  slender 
as  those  of  the  larger  groups  of  O.  arti- 
culata,  and,  like  these,  have  only  here  and 
there  transverse  markings, — for  instance, 
at  the  angles  of  the  branches.  They  are 
also  longitudinally  striped,  and  differ 
fui'ther  from  O.  herherina  by  their  ex- 
pansion upwards  towards  the  base  of 
the  superposed  animalcule.  On  aquatic 
Crustacea  and  Mollusca. 

O.  stenostoma  (Stein).  —  Body  p}Ti- 
fonn,  widest  in  front  of  the  middle  line, 
rounded  anteriorly,  with  a  very  narrow 
periston!,  and  behind  the  middle  strongly 
contracted,  so  as  to  assume  the  appear- 
ance of  a  pedicle.  The  disc  of  the  rotary 
organ  is  very  narrow  across,  fringed  with 
a  single  row  of  cilia;  the  membranous 
process  from  the  oral  cavity  rises  only  so 
much  above  the  periston!  as  to  fori!i  a 
narrow  ani!ular  ridge.    Ni!cleus  long  and 

Genus  ZOOTHAMNIUM  (XII.  67,  68,  69).— Comprehends  Vorticellina 
with  a  spirally  flexible  branched  pedicle  ha\ing  an  internal  muscle.  The 
stalked  corpuscles  are  of  different  shapes  ;  a  wreath  of  cilia  surrounds  the 
frontal  region.  The  mouth  simple  and  lateral.  Numerous  round  stomach- 
cells  (vacuoles)  can  be  demonstrated  by  artificial  feedings.  Self-division  has 
been  observed. 

The  more  accm^ate  examination  of  Stein  supplies  additional  details,  and 
corrects  those  above,  as  given  by  Ehrenberg.  The  so-called  frontal  region  is 
the  peristom  of  Stein,  which  presents  a  rounded  tumid  border,  but  no  cilia ; 
for  these  organs  form  a  fringe  around  a  ciliary  disc  within  the  circumference 
of  the  peristom,  which  can  be  protruded  beyond,  or  retracted  withiii  it.  In 
short,  Zoothamnium,  like  other  Vorticellina,  has  a  ''  rotary  organ,"  which,  by 
the  whirling  of  its  cilia,  di'aws  inward  to  the  mouth,  situated  on  one  side  of 


horseshoe-shaped  ;  contractile  space  cir- 
cular, placed  near  the  coi!!i!!encement  of 
the  oesophagus.  Stem  branched  dichoto- 
mously, but  short,  whei!ce  the  individual 
animalcules  (not  more  than  4-6  in  num- 
ber) are  in  near  apposition.  1-900"; 
length  of  stem  1-360".  The  stiff  stem  is 
si!!all  relatively  to  the  body,  striated 
longitudinally,  and  obscurely  wriulded 
transversely.     On  aquatic  Mollusca. 

O.  7mcrosto7na  (Stein)  (xxx.  37).  — 
Very  similar  to  the  last-named  species, 
like  this,  it  forms  a  lowlj-branched  stem 
bearing  few  animalcules.  The  branches 
are  comparatively  thin,  and  mostly 
marked  by  thickly-set  annular  constric- 
tions, rendering  it  more  or  less  crooked 
and  knotty.  Some  sten!S,  however,  are 
quite  smooth,  and  also  without  trace  of 
longitudinal  striae.  The  animals,  when 
extended,  are  pear-shaped,  and  have  a 
constriction  behind  the  i!!iddle,  and  in 
front  a  very  narrow  periston!.  Rotary 
organ  with  a  shoi-t  steii!  and  a  narrow 
disc;  on  the  opposite  side  of  the  oral 
cavity  is  a  tongue-like  i!!en!bran'Ous  pro- 
cess. "  The  oral  cavity  is  comparatively 
narrow;  the  digestive  tube  short,  the 
contractile  vesicle  lies  near  its  upper 
end,  and  the  C!irved,  hook-like  nucleus 
behind  the  rotary  orgai!.  In  contraction 
the  anii!!al  retains  its  pyrifor!!!  figure, 
and  is  thrown  into  annular  folds  poste- 
riorly. "VVTien  nrore  strongly  contracted, 
it  becomes  oval.  Greatest  length  1-280"  ; 
width  1-450".     On  the  feet  of  Crustacea. 

O.  nutans  (Stein)  =  Epistylis  nutans 
(Ehr.)  ;  but  the  description  by  Ehren- 
berg requires  to  be  niodified  by  the  dis- 
coveries of  Stein,  to  render  it  correct  and 
characteristic.  The  t^^o-lipped  mouth 
is  a  misapprehension  of  the  rotary  organ 
and  membranous  process  of  the  oral 
cavity,  and  the  retractile  palate  is  equi- 
valent to  the  rotary  organ  of  Stein. 


or  THE  VORTICELLLNA. 


595 


it,  a  current  of  water,  together  with  the  nutritive  particles  it  may  contain. 
Within  are  a  curved  semicircular  band-like  nucleus,  a  contractile  vesicle,  the 
so-called  stomach-sacs  or  vacuoles,  and  numerous  granules  and  molecules. 
The  mouth  opens  into  a  wide  oesophagus,  which  extends  backwards  towards 
the  centre  of  the  body,  where  it  terminates  abruptly.  The  stem  essentially 
differs  from  that  of  Carchesium  in  its  central  canal  being  continuous  through- 
out ;  but  the  distinction  drawn  between  the  two  genera  by  Ehrenberg,  from 
the  presence  of  dissimilar  corpuscles  (animalcules)  being  found  in  Zootham- 
niuni,  and  not  in  CarcJiesium,  is  worthless,  as  that  cii^cumstance  is  indicative 
of  nothing  more  than  a  certain  condition  of  development.  The  oldest  portion 
of  the  stem  in  this  genus  often  becomes  soKd  and  rigid,  and  thereby  re- 
sembles that  of  Epistijlis,  for  which  it  might  he  mistaken  (see  p.  293).  Dr. 
Wright  observes  that  the  primary  (parent)  zooid  of  a  polypary  does  not  begin 
to  develope  the  contractile  band  in  its  pedicle  until  this  has  attained  a  con- 
siderable length ;  hence,  for  the  time,  this  primary  zooid  is  an  Epistylis  by 
the  structui-e  of  its  stalk. 


ZooTHAMNitTM  Arbuscula  (Vorticella 
racemosa,  M.  and  Duj.)  (xn.  67,  68,  69) 
has  the  branches  in  racemes  or  irre- 
gular umbels ;  coi^puscles  (zooids)  white, 
campamdate ;  pedicle  very  thick.  These 
beautiful  little  trees  resemble  plumes  of 
feathers.  They  have  the  characters  of 
Carchesium  aud  Opercularia  as  respects 
the  presence  of  globular  bodies  in  the 
axillee  of  the  branches,  but  are  at  once 
distinguished  by  the  strength  of  the 
latter.  Found  upon  Ceratophyllum  and 
other  freshwater  plants,  and  also  in  sea- 
water  ;  \-isible  to  the  naked  eye.  It  con- 
tracts itself  on  its  very  elastic  pedicle  on 
every  alarm.  It  lives  but  a  short  tune 
when  removed  from  its  native  place 
(BrightweU,  p.  344).  Size  1-430" ;  tree 
1-4",  stalk  one-fom*th  the  thickness  of 
the  body. 

Z.  nivmni  (Z.  plumosum,  Wright). — 
Main  stem  zigzag ;  branches  short,  alter- 
nate, almost  yerticUlate,  given  off  from 
each  angle  of  stem ;  zooids  oblong,  cam- 
pamdate, white,  clustered  at  the  ends  of 
the  branches,  which  are  filiform,  the 
lower  ones  often  deserted,  while  the 
upper  bear  clusters  of  club-shaped  little 
bodies  rounded  anteriorly.  Summit  of 
main  stem  and  branches  curved  back- 
wards like  an  ostrich-feather ;  hence  the 
name  plumosum,  proposed  by  Dr.  Wright. 

Z.  affine  (Stein). — Stem  dichotomous ; 
branches  attaining  a  nearly  equal  eleva- 
tion. The  primary  stem  varies  in  length 
as  well  as  the  lateral  ramifications ;  hence 
the  arborescent  polypidom  varies  con- 
siderably in  its  general  aspect,  being  at 
one  time  loose  and  diffiise,  at  others  com- 
pact and  dense.     When  extended,  the 


transparent  branches  are  smooth,  but 
dming  contraction  are  thrown  into  trans- 
verse folds,  and  acquire  a  relative  in- 
crease of  thickness.  The  canal  is  con- 
tinuous throughout,  except  at  the  base  of 
attachment  in  specimens  of  some  age, 
where  the  stem  is  solid  -,  in  its  interior 
is  the  axis-matter, — i.  e.,  in  Ehrenberg's 
language,  the  muscle  moving  the  stem. 
The  animalcides  borne  on  the  extremi- 
ties of  the  branches  are  oval,  somewhat 
contracted  behind,  and  truncate  in  front, 
where  they  are  surmoimted  by  a  thick 
tumid  peristom  of  rather  less  diameter 
than  that  of  the  body.  The  rotary  organ 
is  strikingly  narrower,  and  protrudes 
little  beyond  the  peristom :  in  the  course 
both  of  the  extension  and  retraction  of 
the  rotary  disc  a  fold  is  produced,  which 
gives  the  appearance  of  a  double  peri- 
stom. A  wide  oesophagus  and  digestive 
tube  opens  from  the  mouth ;  and  near  its 
posterior  extremity  is  the  contractile 
vesicle.  The  nucleus  resembles  a  short 
semicircidar  band,  and  lies  across  the 
body.  The  relative  thickness  of  the  stem 
is  a  remarkable  character  of  this  species, 
being  one-half  that  of  the  animalcules  it 
supports.  Usual  length  of  animals  1-380" 
to  1-270'  , 
Entomostraca,  &c. 

Z.  Parasita  (Stein). — Tree-like  poly- 
pary, very  small,  supporting  few  animal- 
cules :  the  latter  agree  in  figure  with 
those  of  Z.  Arbuscula.  Stein  believes  it 
identical  with  Carchesium  pijgm<mim, 
Ehr,,  the  latter  being  an  incompletely- 
developed  form.  On  Entomostraca  and 
small  aquatic  Crustacea. 

We  are  indebted  to  Dr.  Wright  for  a 
notice  of  the  following  species : — 

2q2 


596 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


Z.  dichotoDiiim. — Stem  very  regularly 
dichotomous;  pedicles  long;  zooids  cylin- 


drical, resembling  fruit  of  the  Rosa  eanina. 
7a.  plumosum  (Wright) =Z.  niveum. 


Genus  SCYPHIDIA  (Duj.). — Sessile,  cup-shaped,  tapering  at  the  base, 
covered  with  a  reticulated  integument. 

This  genus  is  received  both  by  Perty  and  Lachmann.  The  former  notices 
three  species,  of  which  one,  ^dz.  Sc.patida,  is  new,  the  two  others  being  8c. 
rlngois  and  Sc.  pyriformis.  Lachmann,  on  the  contraiy,  although  admitting 
the  genus,  rejects  the  species  of  Dujardin  and  Perty,  ''  as  they  have  a  short 
stem,  and  appear  to  be  only  particular  states  of  pedunculate  Vorticellina,  in 
which  the  stem  has  not  attained  its  usual  length ;  but  on  the  other  hand,"  he 
continues,  ''  two  other  beings  must  be  referred  to  it,  both  of  which  attach 
themselves  to  the  naked  parts  of  small  freshwater  mollusca,  and  never  form 
a  stem,  but  which  were  often  observed  by  me  in  process  of  division,  and  are 
easily  distinguished  from  other  forms  which  are,  like  them,  attached  at  first, 
by  their  posteriorly- truncated  form,  and  a  projecting  pad  at  the  margin  of 
the  hinder  end." 


ScYPHZDiA  rugosa. — Obloug,  marked 
with  distant  oblique  deep  striae,  looking 
like  furrows.  1-565".  In  pond-water, 
amongst  vegetable  debris.  To  this  genus 
Dujardin  would  also  attach  the  VoriiceUa 
ringens  and  V.  mcUnans  of  Miiller,  and 
possibly  also  the  V.  pi/rifoi'mis  of  the 
same  author,  under  which  name  Ehren- 
berg  has  described  a  variety  of  V.  conval- 
laria. 

Sc.  pynfonnis. — Grey,  hyaline  ;  with 
no  pedicle,  or  an  extremely  short  one ; 
constantly  contracting  itself.  Uncom- 
mon ;  on  Cyclops,  &c.  Length,  in- 
cluding stem,  1-720"  to  1-600".  Is 
closely  allied  to  Sc.  ringens. 

Sc .  patida  (Perty) . — Widely  campanu- 
late ;  of  a  bluish-grey  colour ;  stem  half 
the  length  of  the  body.  Length,  with 
stem,  1-360".  Uncommon,  with  Tota- 
mogcton. 


Votiicella  hamata  (Ehr.)  is  probably 
another  species,  and  identical  with  V.  in- 
clinans,  which  Dujardin  numbers  among 
the  Scyphidia. 

Sc.  limacma  (Lachmann)  =  Vorticella 
limacina  (Miill.)  (xxix.  3). — Body  nearly 
cylindrical,  tapering  a  little  at  each  end, 
and  annulated ;  periston!  narrow  and  not 
turned  backwards ;  ciliary  disc  naiTow, 
and  furnished  with  a  projecting  umbi- 
licus in  the  middle  ;  the  posterior  trun- 
cated smface  provided  with  a  thick  pad- 
like margin.  ^  1-240"  to  1-360".  Lives 
on  small  species  of  Planorhis. 

Sc.  Physannn  (Lachmann)  is  longer 
and  more  uniformly  cylindrical  than  the 
preceding,  the  periston!  longer  ai!d  often 
tiu*i!ed  backwards  (everted),  and  the 
hinder  margin  thinner  and  shoi'ter. 
Lives  on  the  naked  parts  of  species  of 
Physa. 


Genus  UECEOLARIA  (Lamark  and  Duj.). — Body  not  ciliated  throughout, 
contractile,  varjing  in  shape  from  hemispherical  or  discoid  to  globular ;  sui'- 
rounded  by  a  plane  margin  fringed  Avith  a  row  'of  strong  ciHa  planted 
obliquely,  which  makes  a  spiral  turn  inwards  at  the  oral  apertiu'e,  which  is 
also  situated  on  the  margin. 

Vorticellina  of  different  kinds  have  been  mistaken  for  examples  of  this 
genus,  and  Ehrenberg  has  placed  some  of  its  members  among  the  Trichodince  ; 
indeed  the  type  of  Urceolaria  is  the  Trkliodina  Pedicidiis  of  Ehrenberg. 

Many  species  of  this  genus  are  parasitic  on  freshwater  Mollusca  and  Zoo- 
phytes ;  but  Miiller  mentions  some  found  by  him  in  sea-water. 

There  appear  no  sufficient  grounds  for  instituting  this  genus  when  that 
of  Trichodina  is  admitted,  as  it  is  by  naturalists  generally.  • 

Vb.C'EOI.xtlix  stellma=TncJwdiiui  Pe- \t\\Q  border  of  the  disc  ciliated.  In 
dicidus  (Ehr.).  \  sea-water.    Uncommon.    Ehrenberg  has 

U.  discwa=  Vorticella  discina  QsL). —  j  treated  this  form  as  identical  with  Tri- 
Described  by  Miiller  as  orbicidar,  hoi- |  cAof7/;mP^r7?W//?^<?,  but,  as  Dujardin  thinks, 
lowed  out  alDove,  convex  beneath   .  .  .  ;     erronooiisly.     However,  it  is  impossible 


OF  THE  VORTICELLINA. 


597 


accurately  to  decide  what  the  being  I  U.  Di(jardiun=  Vorticella  hursata  and 
which  :Mliller  met  with  is,  from  the  ac-  I  V.  utriculata  (Miill.).— Capsular  or  utri- 
count  he  has  left  us.  I  cular  in  shape,  bellied  posteriorly,  cili- 

U.  //;n«e<V?rt.— Sessile,  cylindrical,  dia-  ;  ated  on  the  anterior  margin.  Midler 
phanous  ;  orifice  truncated,  with  2  or  4  distinguished  this  being  under  two  fonns, 
indistinct  cilia  (according  to  Miiller),  or,  ;  one  of  which  he  described  as  having  a 
as  we  mav  presume,  with  a  circlet  of  :  projecting  papilla  at  the  centre  oi  the 
cilia  around  the  margin  of  the  wider  ex-  !  anterior  surface,  capable  of  elongating  it- 
tremity,  and  a  collection  of  cilia  at  the  :  self.  In  sea-water. 
naiTower  base,  by  which  the  animal  at- 
taches itself.  Parasitic  on  the  tentacles 
of  Bidla  and  Planorhk. 


These  species  of  Miiller  appear  to  us 
too  indistinct  to  insist  on  as  independent 
forms. 


Genus  CHiETOSPIRA  (Lachmann)  (XXXIX.  5,  6).— The  surface  gene- 
rally covered  with  cilia,  like  the  genus  Stentor,  from  which  it  is  distin- 
guis^hed  by  having  that  part  of  the  parenchyma  of  the  body  which  bears 
the  ciliaiy  spii^al  and  the  anus  (which  in  all  the  Stentorinoe  lies  on  the  dorsal 
siuface  of  the  body,  close  under  the  ciliaiy  spiral,  and  not  in  a  common  pit 
with  the  mouth)  tow^n  out  into  a  thin  process.  This  process  is  narrow 
and  bacillar ;  the  series  of  cilia  commences  at  its  free  extremity,  and  only 
forms  a  spiral  when  in  action  by  the  rolling-up  of  the  lamina.  The  process 
bears  the  anus.  The  animalcules  inhabit  a  sheath  or  tube,  of  a  mucilaginous 
or  even  horny  density.  "  It  is  possible  that  the  free-swimming  SticJiotricha 
secunda  of  Perty,  which  he  arranges  with  the  Oxytrichinae,  is  allied  to  Chce- 
tospira ;  his  figiu'e,  however,  is  very  inexact,  and  might  perhaps  represent  a 
Loxodes  or  Amj)hileptus  FascioJa  ;  and,  as  he  does  not  desciibe  the  position  of 
the  anus,  which  he  never  figm^es,  any  more  than  the  contractile  vesicle  and 
the  nucleus,  I  do  not  ventiu'e  to  place  his  Stichotricha  with  the  Stentorinae. 
K  it  should  tui-n  out  that  it  belongs  to  that  family,  it  must  be  placed  beside 
the  analogous  sheath-inhabiting  Chcestosjnra,  as  a  genus  not  inhabiting  a 
sheath." 

Ch^tospiea  3//7//m  (xxix.  5,6).—  Ch.«»^c/oo/«.— Enclosing  tube  mucous 
Slender.  Thefirst  cilia  of  the  series  upon  in  consistence;  animalcule  shorter  and 
the  process  are  somewhat,  but  not  re-  more  compressed;  the  roUed-up  ciliary 
markably  longer  and  stronofer  than  the  !  process  does  not  form  a  complete  turn  of 
rest ;  when  roUed  up,  the  ciliated  bacillar  I  a  spiral ;  the  first  cilia  are  considerably 
process  forms  more  than  one  turn  of  a  ',  larger  than  the  rest,  the  first  one  espe- 
spiral.  Sheath  fla^sk-shaped  and  horny,  j  cially  being  nearly  t^dce  as  long  as  most 
Hitherto  found  only  in  the  open  cells  of 
torn  leaves  of  Lemna  triscidca,  growing 
in  fresh  water  near  Berlin. 


of  the  others. 


Genus  CCEXOMOPPHA  (Perty)  (XXYIII.  27-30).— SmaU,  hyaline,  of  a 
beU-like  or  hemispherical  figure,  concave  at  its  truncated  base,  which  has  an 
irregularly  notched  margin,  and  a  tail-like  process  depending  from  it  at  its 
centre.  Rim  of  the  bell  furnished  with  long  cilia.  Except  in  the  absence  of 
the  long  tentacula,  these  beings,  according  to  Perty's  figures,  have  a  general 
resemblance  to  minute  campanulate  Medusce  ;  or,  otherwise,  they  may  be 
likened  to  miniature  parasols  with  fringed  edges  and  a  short  handle. 

Perty  has  placed  this  genus  in  his  family  IJrceolarina,  which  is  equivalent 
to  that  called  Stentorina  by  Lachmann.  But,  to  oiu'  mind,  much  doubt  must 
attach  to  this  assigned  position,  for  not  only  is  there  a  very  great  departure 
from  the  general  form  of  every  genus  of  YorticeUina,  as  Perty  himself  could 
not  fail  to  remark  ;  but,  from  his  figiu-es,  no  characteristic,  no  internal  organ- 
ization appears  to  establish  the  organic  affinities  of  these  curious  beings. 


598 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


CcENOMORPHA  ^ledustdci  (XX\^II.  27- 
30). — Colourless,  transparent,  ^dth  a 
small  number  of  internal  vesicles  and 
molecules.     Lenglb    tog-ether  with  the 


tail,  1-240"  to  1-190".  It  s^\^ms  actively 
and  rotates  on  itself,  undergoing  various 
changes  in  outline.  Some  specimens  ex- 
hibit folds  of  the  surface. 


Genus  8PIR0CH0NA  (Stein)  (XXX.  17-20,  27,  28).— Body  naked,  but 
having  a  firm  corneous  integument ;  attached  perpendicularly  by  its  base, 
and  quite  motionless ;  of  an  elongated,  flask-like  shape,  with  an  anterior, 
spirally-convoluted,  funnel-like  head  or  peristom.  Posteriorly  it  narrows  to 
a  small  base,  whereby  it  is  fixed  either  immediately  or  mediately  by  a  very 
short  pedicle.  The  infundibiiliform  spiral  peristom  surmounts  a  constricted 
portion  or  neck.  The  sj^iral  lamina  forming  the  peristom  terminates  abruptly 
below,  so  as  to  leave  a  cleft,  which  conducts  to  the  mouth ;  its  upper  portion 
is  roUed  around  the  longitudinal  axis  of  the  peristom,  and  produces  a  solid 
central  pivot.  The  innermost  turn  of  the  lamina  constitutes  a  funnel,  which 
siu-mounts  the  whole  peristom,  and  with  the  next  coil  forms  what  Stein  calls 
the  "  spiral  funnel,"  whilst  the  lowest  and  widest  spiral  represents  the  true 
peristom,  homologous  with  the  ciliary  spii^al  or  peristom  of  Vorticella.  The 
latter  is  richly  covered  vdth  cilia,  which  extend  in  less  number  to  the  second 
coil.  Internally,  a  digestive  tube  is  seen  to  extend  a  considerable  distance 
from  the  mouth,  having  a  contractile  vesicle  placed  near  its  termination.  A 
large  nucleus  is  seated  near  the  middle  of  the  animal,  having  a  clear  central 
space  or  nucleolus.  Fission  has  not  been  witnessed ;  but  gemmae  are  fre- 
quently produced,  which,  under  certain  cii'cumstances,  become  encysted,  and, 
as  Stein  believes,  undergo  an  Acinetiform  metamorphosis  (XXX.  21-28). 
Length  1-750"  to  1-216";  breadth  of  largest  1-600". 


^'PiROQ^o^x  c/emmipara  (xxx.  17-20). 
■ — The  above  description  applies  spe- 
cially to  this  form.  Found  on  the  ova- 
eapsides  of  Gammarus  and  other  Ento- 
mostraca,  in  fresh  water. 

Sp.  Scheutenii  (xxx.  27,  28)  agrees 
with  the  foregoing  in  size  and  figure ; 
but  the  peristom  is  more  simple,  consist- 
ing of  little  more  than  a  single  coil  of  a 


wide  lamina,  and  has,  besides,  a  series  of 
stifi"  fibrous  processes  fringing  it  on  one 
side.  The  internal  face  of  the  funnel  is 
lined  with  cilia  below.  Found  on  Ento- 
mostraca  in  brackish  water  near  Am- 
sterdam by  M.  Scheuten;  they  are  at- 
tached to  the  long  feathery  bristles  of 
the  post-abdominal  feet,  and  not  to  the 
ova-capsules,  like  S.  gemmipara. 


FAMILY  lY.— OPHEYDINA  (VAGINIFERA). 
(XXYII.  10-15 ;  XXYIII.  18-20,  23 ;  XXX.  29-35.) 

Loricated  polygastric  animalcules,  solitary  or  aggregate,  possessing  a  distinct 
alimentary  canal,  a  separate  mouth  and  discharging  orifice,  which  approxi- 
mate and  terminate  in  the  same  spot.  In  organization  it  resembles  the 
family  Yorticellina ;  in  fact,  continues  Ehrenberg,  it  includes  true  Vorticellce 
or  Stentors,  enclosed  in  a  gelatinous,  membranous,  combustible  lorica.  Be- 
sides the  usual  frontal  wreath  of  cilia,  there  is  in  OiDhrydimn  a  second  wreath 
placed  posteriorly ;  and  Tintinnus  has  an  clastic  muscular  stalk  or  tail.  Al- 
though, as  Ehrenberg  teUs  us,  the  pol3^gastric  organs  of  nutrition  can  be 
demonstrated  in  all  the  tribe  by  using  coloured  food,  it  is  only  in  Ophryd'mm 
that  an  alimentary  canal  has  been  distinctly  seen.  Longitudinal  division  of 
the  body  takes  place  within  the  lorica,  which  continues  unaffected.  In 
Ophrydium  transverse  division  has  been  doubtfully  affirmed. 

The  genera  are  disposed  as  follows : — 


OF  THE  OPHEYDINA.  599 

Forming  Monad-clusters,  tlu-ough  incomplete  self-division  of  the  lorica Ophrydium. 

/  Body  furnished  with  an  elastic  pedicle  attached  1  m-  ^• 

!       to  lorica J     ^'^  muu-  • 

Lorica  stalkless  Vaginicola. 


Animalcules    solitary,    no  J 
self-division  of  the  lorica  "^ 


Body  stalkless. 

Lorica  stalked Cothurnia. 


Of  the  genera  composing  this  family,  Ophrydium  is  arranged  by  Dujardin 
with  the  Urceolarina,  and  Vaginicola  with  the  Yorticellina.  This  author 
writes — 

*'  The  so-called  lorica  of  Oplirydia  (Duj.,  or  Oplirydium)  is  an  amorphous 
gelatinous  investment,  unlike  that  of  Vaginicola,  which  is  a  truly  resistant 
enveloping  membrane.  The  individual  beings  in  the  gelatinous  ball  of 
Oplirydia  are  elongated,  cylindrical,  or  fusiform,  and  capable  of  varying  their 
figui^e." 

Further,  Dujardin  includes  Tintinnus  and  CortJiurnia  in  the  genus  Va- 
ginicola. 

Stein  enumerates  Tintinnus  among  the  genera  of  Ehrenberg's  Ophrydina, 
but  offers  no  account  of  it.  He  rejects  the  distinction,  as  does  Dujardin, 
between  Vaginicola  and  Cothurnia,  and  would  transfer  the  whole  of  this 
family,  so  reduced,  to  Yorticellina,  with  which  its  members  have  the  greatest 
similarity  in  organization.  Perty  adopts  the  the  title  Ophrydma,  but  com- 
prehends under  it  only  the  single  genus  Opjhrydimn.  Lachmann  rejects 
Tintinnus  from  the  list. 

The  characters  laid  down  by  Ehrenberg,  of  this  family,  are  very  unsatis- 
factory. Its  members  cannot  be  said  to  be  loricated  in  the  same  way  as 
Colepina  or  Euplotina ;  for  in  these  the  lorica  consists  of  a  thickened,  closely- 
adlierent  integument,  whilst  in  Ophrydina  the  structure  so  called  is  a  loose 
sheath,  open  at  one  extremity,  which  may  in  some  be  seen  gradually  excreted 
from  and  built  up  around  the  animalcule,  which  last,  moreover,  has  a  distinct 
integument  of  its  own.  In  the  Ophrydina,  therefore,  it  is  rightly  called  a 
sheath,  case,  or  tube.  Ophrydium,  indeed,  is  exceptional;  for,  though  it 
secretes  a  large  quantity  of  miico -gelatinous  substance,  it  never  builds  this 
up  around  it  into  a  sheath,  but  merely  sends  into  it  a  long,  tapering,  fibrous 
prolongation  from  its  posterior  extremity  to  secui^e  a  firm  hold,  whilst  its 
body  projects  freely  from  the  mass  (see  Part  I.  p.  282).  Moreover,  it  is 
this  genus  only  that  is  aggregated,  all  the  rest  being  solitary.  These  pecu- 
liarities may  be  held  to  justify  Perty  in  erecting  this  genus  into  a  family. 

The  presence  of  numerous  stomachs  and  of  a  distinct  alimentary  canal,  it 
need  only  be  said,  are  details  of  organization  requii^ed  by  the  hypothesis  of 
Ehrenberg,  and  supposed  in  some  instances  to  be  demonstrated  by  feeding 
with  colouiing  matters. 

As  Ehrenberg  rightly  intimates,  Ophrydina  may  be  briefly  defined  as  Yor- 
ticellina living  in  a  sheath,  instead  of  being  supported  on  a  pedicle.  From 
this  general  definition  Ophrydium  is  necessarily  excluded  as  an  exceptional 
form  ;  and  it  becomes,  therefore,  a  matter  of  regret  that  a  family  should  be 
named  from  a  genus  in  no  sort  its  true  type.  Perty  has  invented  the  name 
"  Yaginifera  "  for  a  family  containing  the  two  genera  Vaginicola  and  Co- 
tliurnia  ;  and  it  is  certainly  preferable  to  Ophrydina,  whether  Ophrydium  be 
comprehended  in  it  or  not. 

Genus  OPHRYDIUM  (XXX.  5,  6). — Lorica  gelatinous ;  animals  clustered, 
in  consequence  of  perfect  self-division  of  the  body,  but  imperfect  of  the 
lorica.     This  circumstance  gives  rise  to  very  peculiar  external  appearances ; 


GOO 


SYSTEMATIC  HISTORY  OF  THE  INFUSOIIIA. 


for  each  body  veiy  frequently  divides  itself,  the  two  portions  separating 
entirely, — the  gelatinous  lorica  forming  only  a  separating  wall.  In  this  manner 
thousands  and  millions  of  connected  animal- cells  are  quickly  formed,  appear- 
ing as  gelatinous  globular  masses  or  balls. 

It  is  a  misapprehension,  on  the  part  of  Ehrenberg,  of  the  actual  phaeno- 
mena,  when  he  states  that  the  large  gelatinous  ball  formed  by  the  multipli- 
cation of  Ophnjdia  is  the  result  of  imperfect  fission  of  the  lorica;  for,  as  we 
have  pointed  out,  the  animalcules  have  no  lorica  or  sheath  in  the  sense 
Ehrenberg  intended,  but  are  merely  attached  by  a  sort  of  non- contractile 
stalk  penetrating  far  in  the  interior,  upon  the  surface  of  the  gelatinous  mass. 
"When  fully  contracted,  indeed,  it  is  drawn  down  upon  and  sHghtly  presses 
into  the  soft  mass,  raising  this  as  a  rim  around  it ;  consequently  it  is  also  an 
error  to  say  that  the  mass  is  composed  of  numberless  little  cells,  seeing  that 
nothing  like  a  ceU  is  constructed  around  the  animalcules.  Stein  found  within 
the  interior  of  the  gelatinous  mass  numerous  intertwining  and  twisted  fibres, 
which  he  concluded  were  vegetable  parasites,  probably  of  the  family  Lepto- 
mit£e.  Agardh  and  other  botanists  have  described  the  gelatinous  baUs  of 
Ophrydium  as  a  species  of  Nostochinese,  under  the  name  of  Nostoc  pruni- 
fonne ;  but  this  is  a  great  mistake,  for  no  cellular  or  proper  vegetable  struc- 
ture is  present. 

Stein  has  added  to  the  vaginated  YorticeUina,  or  the  Ophrydina,  the  genus 
Lagenophrys ;  and  Dr.  Wright  {Ed'm.  New  Phil.  Journ.  1858)  the  interesting 
genus  Lagotia. 


OpHHYDirM  versatile  (Trichoda  inqui- 
lina  et  VorticeUa  versatilis,  M.)  (xxiii.  5, 
6). — Body  fusiform,  tapering  to  a  fine 
extremity  from  behind  the  middle,  and 
anterior  to  it  contracted  into  a  cylin- 
drical neck,  supporting  a  funnel-shaped 
head  surmounted  by  an  annidar  periston! 
with  a  ciliated  rotary  disc.  The  mouth 
opens  into  a  narrow  and  long  ciliated 
oesophagus.  The  contractile  vesicle  is 
seated  near  its  end ;  the  nucleus  is  long, 
narrow,  and  twisted.  The  external  sur- 
face is  thrown  into  close  annular  folds  ; 
and  usually  three  longitudinal  plaits  ex- 
tend from  the  posterior  end  as  far  as  the 
middle  of  the  body,  which  disappear 
when  the  body  contracts.  A  subjacent 
cortical  lamina  is  evident,  and,  imbedded 
within  this,  numerous  chlorophyll  utri- 
cles, giving  the  animal  a  vivid  green 
colour.  When  contracted,  the  body  as- 
sumes the  fomi  of  a  long-necked  flask,  animalcide 
and  even  the  nucleus  shortens  itself,  j  1-90". 
In  more  complete  contraction  the  figure  j 

Genus  TIT^TINNUS. — Ophrydina  which  possess  divisibility  of  the  body, 
but  not  of  the  urceolate  lorica ;  the  body  is  attached  to  the  interior  of  the 
sheath  by  a  flexible  pedicle  (somewhat  similar  to  the  clapper  of  a  bell) ;  the 
mouth  serves  both  as  a  receiving  and  discharging  orifice ;  stomach-cells  and 
traces  of  a  yellowish  ova-cluster  are  more  or  less  visible ;  self-division  was 
known  to  Miiller. 

Tintinmis,  as  before  noted,  is  a  genus  not  admitted  by  Dujardin ;  Perty 
likewise  ignores  it ;  and  Lachmann  {A.  N.  H.  1857,  p.  119)  feels  the  necessity 
of  excluding  it  from  YorticeUina  (using  this  term  in  a  wider  sense,  so  as  to 


becomes  oval  or  globular.  Fission  is 
only  longitudinal ;  when  an  Ophrydium 
quits  its  hold  after  fission,  it  swims  away 
by  means  of  a  temporarily  developed 
posterior  wreath  of  cilia,  just  like  a  Vor- 
ticeUa. It  is  found  encysted,  and,  Stein 
believes,  in  an  Acinetiform  phase  (xxx. 
7,  8).  Yividly  green,  and  associated  in 
smooth  and  globular  clusters  or  masses, 
which  vary  in  size  from  a  pea  to  a  ball 
five  inches  in  diameter ;  they  are  either 
free  or  attached.  Ehrenberg  states  that, 
in  May  1837,  he  saw  hundi'eds  of  clusters 
as  large  as  the  fist,  which,  by  the  evolu- 
tion of  gas,  were  at  intervals  elevated  to 
the  surface,  and  driven  by  the  wind  to 
the  edge  of  the  water.  In  sea- water; 
also  found  by  Brightwell  in  fresh  water, 
and  in  a  small  turf-pit,  upon  tendrils  of 
roots  of  marsh-plants,  and  the  stalks  of 
the  white  water-lilv-     Leng-th  of  single 


stretched    out,    1-120"    to 


OF  THE  OPHRTDIXA.  601 

include  Opliiydiiia),  since  it  is  ciliated  all  round,  and  differs  greatly  from  them 
in  the  form  of  its  alimentary  apparatus.  Moreover,  a  species  inhabiting  a 
gelatinous  sheath  occurs  in  the  freshwater  ponds  in  the  Thiergarten  at  Berlin. 

TiXTiNNUS  inquilinus.  —  Hyaline  or 
yellc^asli ;  lorica  cylindi-ical,  glass-like, 
bell-shaped.  1-570",  with  stalk  1-240". 
lu  sea- water,  on  xilgae. 

T.  subulatus  (  Vorticella  vaginata,  M.). — 
Hyaline ;  sheath  conical,  with  a  posterior 
subulate  elongation.  Ehrenberg  obseryes 
that,  if  this  elongation  of  the  lorica  Avere 


called  a  stalk,  we  shoidd  require  a  new 


drical,  hyaline,  indistinctly  annidar :  ra- 
ther attenuate  and  truncate  posteriorly. 
1-440".     In  the  Baltic. 

T.  Campanula. — Hyaline;  sheath  widely 
campanulate,  dilated  in  front,  pointed 
behind.  1-290".  In  North  Sea  and 
Baltic. 

T.   denticulatus.  —  Sheath  cylindrical, 
hyaline,  sculptured  with  oblique  rows  of 


generic  name  for  the  animalcule.  Length  I  dots,  fi-ont  margin  acutely  dentate ;  pos 
of  lorica  1-90".  terior  extremity  pointed.     1-220".     In 

T.  Cothurnia. — Hyaline  ;  sheath  cylin-  !  the  North  Sea. 

Genus  YAGINICOLA  (XXYII.  10,  11  ;  XXYIII.  18,  19).— Neither  the 
body  nor  the  lorica  stalked ;  a  Avreath  of  cilia  surrounds  the  truncated  front 
portion,  mthin  which  is  the  orifice  or  mouth.  The  polygastric  apparatus, 
the  passage  of  the  food  onwards,  its  return,  and  the  exit  of  the  refuse  near 
the  mouth,  and  coloured  ova-granules,  are  mentioned  by  Ehrenberg.  In- 
crease by  longitudinal  self-division  of  the  body  (not  of  the  lorica)  has  been 
seen  in  all  the  species. 

To  the  above  account  must  be  added,  according  to  Stein's  observations, 
that  the  body  of  Vaginicola  has  in  front  a  peristom,  from  out  of  which  a 
"  rotary  apparatus  "  protrudes,  consisting  of  a  ciliated  disc,  supported  on  a 
stout  stem  or  pedicle,  just  like  that  of  Vorticella.  A  mouth  opens  on  one 
side  of  the  disc,  and  leads  into  an  cesophagus  ;  but  no  polygastric  structure,  as 
sui'mised  by  Ehrenberg,  is  \isible,  although  numerous  alimentary  vacuoles 
are  usually  present.  Ova-granules,  again,  are  merely  hypothetical,  and,  as 
in  other  Infusoria,  where  mentioned  by  Ehrenberg,  represent  particles  of 
various  kinds,  but  mostly  coloured  granules.  In  a  new  species  noted  by 
Dr.  Wright,  the  tubular  sheath  has  a  peculiar  structm-e  in  the  form  of  a 
valve,  which  closes  over  the  animalcule  when  it  retreats  to  the  bottom  of  its 
case  (XXYIII.  18,  19). 

In  all  the  particulars  of  internal  organization,  Vaginicola  resembles  Vorti- 
cella. Propagation  by  fission  and  gemmation  is  very  distinct ;  by  the  former 
process  more  common  (XXYII.  10,  11).  The  development  of  the  bud  takes 
place  from  the  base  of  the  parent,  and  within  its  sheath.  The  young  being, 
produced  by  either  process,  is  furnished,  as  in  Vorticella,  with  a  posterior 
wreath  of  cilia,  whilst  it  is  endoAved  with  free  locomotion  (XXYII.  11).  It 
frequently  happens,  as  represented  in  the  last-quoted  figure,  that  the  young 
being  assumes  on  its  formation  a  contracted  ovoid  foiTu,  with  its  frontal  Avreath 
retracted.  Upon  the  appearance  of  the  posterior  whorl  of  cilia,  and  aided  by 
its  movements,  the  animal  loosens  itself,  escapes  from  the  parent-case,  and 
swims  freely  away,  elongating  itself,  it  may  be,  if  previously  contracted,  and 
assuming  finally  all  the  characters  of  a  perfect  Vaginicola,  by  developing 
around  it  its  own  special  sheath. 

On  the  other  hand,  the  contracted  indiA-idual  may  become  actually  encased 
within  its  integument  (in  other  words,  encysted),  and,  as  Stein  believes, 
may  thereupon  assume  all  the  characters  of  an  Acineta,  and  eventually  give 
birth  to  a  ciliated  embryo  (XXYII.  11-15).  This  metamorphosis,  however, 
is  not  generally  accepted.  The  specific  characters  in  this  genus  are  for  the 
most  part  deduced  from  the  figure  and  dimensions  of  the  external  sheath  or 
lorica  (Ehr.),  and  must,  therefore,  as  Stein  points   out.  be  admitted  with  much 


602 


SYSTEMATIC  HISTOEY  OF  THE  IXFUSORIA. 


reservation ;  for  this  envelope  changes  greatly  in  figure,  in  size,  and  structure, 
according  to  the  age  and  the  different  vital  conditions  under  which  the  animal 
lives.  Stein  met  with  one  example  in  which  a  short  pedicle  attached  the 
Vaginlcola  crijstaUma  to  the  bottom  of  its  sheath :  indeed  he  does  not  admit 
Cothuniia  and  Vaf/inicola  to  be  generically  distinct ;  for  the  stems  supporting 
the  sheath  of  the  former  are,  he  says,  not  generally  longer  than  those  belong- 
ing to  young  Vaguucolce.     In  this  point  therefore  he  agrees  with  Dujardin. 

We  have  observed  how  close  the  resemblance  is  between  Vorticella  and 
Vag'micola ;  on  the  other  hand,  the  points  of  separation  are  found  in  the 
absence  of  a  pedicle  in  the  latter,  which  is  fixed  to  the  bottom  of  a  sheath  by 
its  posterior  extremity,  its  anterior  remaining  free,  and  its  whole  body 
capable  of  extension  or  retraction  within  the  orifice  of  its  case.  Lastly,  the 
figure  of  the  body  is  much  more  elongated  in  Vaginicola  than  in  Vorticella. 


Vaginicola  crystallina  (Vorticella 
stentorea  et  TricJiocla  ingemta,  M.)  (xxvii. 
10,  11). — Sheath  crystalline,  straight, 
pitcher-shaped,  slightly  contracted  near 
the  open  end ;  granules  green.  Length 
of  lorica  1-210".     Upon  Lemna,  &c. 

V.  tincta. — Sheath  bro^niish-yellow, 
urceolate,  and  nearly  cylindrical;  body 
hyaline.  Length  of  lorica  1-280".  Upon 
Zygnema  decimum. 

V.  decumhens. — Sheath  brownish  yel- 
low, oval  and  compressed,  decumbent  on 
one  side,  which  is  flattened ;  the  body 
hyaline.     Length  of  lorica  1-280". 

Stein  corrects  this  description  by 
stating  that  the  oval  plano-convex  sheath 
has  not  a  simple  crescentic  opening, 
but  is  contracted  so  as  to  form  a  short 
tubular  neck,  or  projecting  process,  with 
a  transversely  oval  or  reniform  mouth. 
It  has  consequently  the  closest  resem- 
blance to  the  sheath  of  Lagenophrys  A?n~ 
pidla  ;  but  its  orifice  is  rigid,  and  not  con- 
tractile as  in  the  latter,  and,  further, 
the  animalcule  is  not  afiixed  to  its  mar- 
gin, but  to  the  bottom.  On  Lemna, 
Zygnema,  &c. 

V.  valrata  (Wright)  (xxviii.  18,  19). 
— Distinguished  from  V.  crystallina  by 
the  remarkable  valve  existing  in  its  case 
or  sheath — which  closes,  in  an  inclined 
position,  over  the  animal  when  it  retreats 
to  the  bottom  of  its  case ;  by  the  body 
being  colourless,  without  the  green  glo- 
bules seen  in  V.  crystallina ;  and  by  being 
an  inhabitant  of  sea-water  instead  of 
fresh.  Plentiful  on  zoophytes  and  sea- 
weeds. 

V.  vaginata. — Under  the  name  Vorti- 
cella vaginata,  Midler  described  a  Vagi- 
nicola found  in  the  Baltic,  having  a  deli- 
cate pedicle  as  long  as  the  body,  which 
is  supported  by  it,  at  the  upper  end  of  a 
sheath  six  times  longer  than  itself,  into 
the  orifice  of  which  it  can  with  difficulty 
enter. 


V.  pedunculata  (Eichwald).  —  Body 
attached  to  the  bottom  of  the  sheath  by 
a  short  stem.  This  presumed  species  is 
actually  nothing  more  than  a  variet}^  of 
F.  crystallina,  as  Stein  has  shown. 

V.  Amjndla. — Miiller  described  this  as 
larger  than  most  animalcides,  as  dwelling 
in  a  bottle-shaped  sheath,  as  A'ery  con- 
tractile, grey,  and  soft,  and  as  occupying 
various  positions  witliin  the  case.  Fomid 
in  the  Baltic,  and,  by  Mr.  Brightwell,  at 
Lowestoft.  Dr. Wright  (J^din.  Phil.  Journ. 
1858,  p.  5)  says  it  has  a  bilobed  ciliated 
organ,  and  so  far  resembles  Lagotia. 

V.  ovata  (Duj.). — Body  of  a  lengthened 
ovoid  figure,  placed  in  an  urceolate  case. 
Length  of  body  1-1000",  of  case  1-550". 
Apparently  distinct  from  V.  crystallina. 
On  Zygnema  in  pond-water. 

V. ?  (Brightwell)  (xii.  70).— 

Body  double,  of  a  green  colour.  Pro- 
bably undescribed.  On  duck-weed  and 
other  small  aquatic  plants.  It  is  doubt- 
fid  whether  this  being  is  other  than  a 
Vaginicola  in  process  of  spontaneous 
fission. 

V.  grandis  (Perty). — Sheath  cylindri- 
cal. Animals  A\dth  a  circular  ciliated 
opening.  Length  of  tube  1-108",  of  the 
extended  animal  1-84".  Stein  considers 
this  species  a  mere  variety  of  V.  cry- 
stallina ;  but  besides  differing  from  it  in 
size,  it  does  so  also  in  the  figm'e  of  its 
sheath,  which  is  not  rounded  below,  but 
abruptly  truncate,  and  not  nan'ower 
above,  but  rather  wider.  Animalcules 
hyaline,  often  filled  with  sporozoids  and 
chlorophyll  gTanules ;  wheri  contracted 
it  does  not  occupy  more  than  a  third  of 
the  tubular  sheath.  Among  water-plants. 
Uncommon. 

The  figure  of  this  species  presented  by 
Perty  is  very  rude,  convejdng  not  the 
slightest  conception  of  the  details  of 
external  structure  or  of  internal  organ- 
ization. 


OF  THE  OPHEYDINA. 


603 


Genus  COTHURXIA  (XXX.  12-16).— Lorica  (sheath)  urceolate,  and  sup- 
ported on  a  rigid  pedicle.  A  wreath  of  cilia  is  placed  upon  the  flat  frontal 
region ;  and  the  mouth,  with  the  anal  opening,  lies  on  one  side,  within  the 
vestibulum.  The  body  is  contractile,  and  can  withdraw  itself  within  the 
stiff  sheath ;  fission  longitudinal. 

It  is  unnecessary  to  enlarge  on  the  structural  details  of  this  genus,  inas- 
much as  they  are  in  aU  particulars  like  those  of  VaginicoJa,  from  which  it  is 
separated  only  by  its  sheath  being  stalked. 

aspect.  The  two  angles  in  front  are  ex- 
tended upwards  and  outwards,  but  at  the 
same  time  curved  inwards  at  their  ex- 


CoTHUBNiA  imherhis  (Vorticella  folli- 
culata,  M.). — Pedicle  mostly  bent  and 
much  shoi-ter  than  the  sheath,  which 
has,  when  old,  a  yellowish  colour. 
Sheath  tubular,  narrowed  anteriorly, 
without  an  everted  margin.  Even  when 
outsti-etched,  the  animal  extends  little 
beyond  the  mouth  of  the  sheath;  its 
periston!  is  scarcely  appreciably  thick- 
ened, and  not  everted  at  all ;  it  is  evi- 
dently ciliated.  The  disc  of  the  simple 
rotary  organ  is  level  on  its  surface,  and 
scarcely  rises  above  the  sheath.  Diges- 
tive tube  long  and  narrow,  extends  be- 
yond the  centre  of  the  body,  and  near 
its  commencement  has  fi-om  3  to  4  long 
cilia.  Near  to  it,  on  one  side,  is  a  round 
contractile  vesicle,  and  on  the  other  a 
short,  band-like  nucleus,  almost  straight 
or  slightly  reniform  in  figure.  Longi- 
tudinal fission  frequently  observed,  and 
sufficiently  often  the  process  of  gemma- 
tion at  the  base.  Length  of  sheath  1-288" 
to  1-240". 

Ehrenberg  remarks,  "  This  animalcule 
had  often  'swallowed  gTcen  Monads,  and 
yet  accepted  indigo.  Trichoduui  vorax 
is  the  enemy  of  this  species."  Upon 
Cyclops  quadricornis.  Length  of  sheath 
1-280". 

C  maritima. — Pedicle  much  shorter 
than  the  hyaline  sheath;  body  hyaline 
and  whitish.    Length  of  sheath  1-570''. 

C.  maritima  is  very  closely  aUied  to 
VaginicoJa  crystallina :  not  the  least  dif- 
ference between  the  animals  themselves 
is  perceptible,  and  the  figure  of  the 
sheath  is  the  same, — the  only  essential 
difterence  being  that  in  the  Cothurnia 
the  sheath  is  supported  on  a  thin,  solid 
stem,  1-48"  to  1-36"  in  diameter  and 
of  a  length  equal  to  its  own. 

C.  Havniemis. — Pedicle  much  longer 
than  the  hvaline  sheath ;  body  whitish, 
Leng-th  without  stalk  1-280". 
^  C.  Sieholdii  (Stein)  (xxx.  13,  14).— 
Sheath  stalked ;  stalk  short,  thick,  colour- 
less, transversely  and  deeply  vviinkled, 
and  thickened  at  its  junction  with  the 
sheath.  The  last  is  campanulate,  strongly 
compressed  in  fi-ont,  dilated  and  bellied 
out  posteriorly,  especially  on  the  dorsal 


tremities  as  two  horns.  The  waUs  of 
the  sheath  are  at  first  soft,  colourless, 
and  hyaline,  but  subsequently  become 
yellow  and  leathery,  and  at  last  of  a 
more  or  less  deep  rusty  brown  colour, 
and  of  a  corneous  consistence.  The 
colomless  and,  with  reference  to  the 
sheath,  small  contained  animal  is  cylin- 
drical in  figure,  contracted  behind,^  and 
ver}^  similar  to  that  of  Vayinicola  crystal- 
Una.  Its  periston!  forms  an  annidar 
thick  border,  and  is  beset  with  few  cilia. 
The  digestive  tube,  which  extends  to 
nearly  the  centre  of  the  body,  has  close 
to  it  the  contractile  vesicle,  and  a  little 
fm-ther  behind,  the  thick,  short  band-like 
and  semicircular  nucleus,  visible  without 
the  use  of  chemical  reagents.  Multipli- 
cation takes  place  by  longitudinal  fission. 
Length  of  largest  sheaths  1-190".  On 
the  limbs  and  other  parts  of  Eutomos- 
traca ;  very  abundantly. 

C.  Astaci  (Stein)  (xxx.  15). — Sheath 
supported  on  a  short,  w!'inkled,  thick 
pedicle;  having  itself  a  tubular  figure, 
rather  contracted  at  the  middle,  and  its 
border  widened  and  everted,  whilst  its 
posterior  half  is  slightly  ventricose  and 
rounded  at  its  extremity.  Its  consist- 
ence is  leathery  or  hon!y  when  old ;  it 
is  transparent  and  of  a  pale  yellow  colour, 
but  never  a  rusty  browTi.  When  fully 
outstretched,  the  animal  protrudes  a  con- 
siderable distance  beyond  the  mouth  of 
the  sheath,  differing  in  this  respect,  as 
well  as  by  its  thick  annidar  peristom  and 
its  cylindrical  outline,  from  Cothurnia 
imherbis.  The  digestive  tube  attains  the 
middle  of  the  animal,  is  very  narrow, 
and  has  both  the  contractile  vesicle 
and  the  short  band-like  nucleus  placed 
near  its  tennination.  Fission  is  longi- 
tudinal. 

Old  specimens  attain  a  height  of 
1-288",  and  a  width  of  1-600".  Also 
found  on  Entomostraca.  It  is  very  closely 
allied  to  C.  imberhis ;  but,  besides  the 
differences  noted  between  the  animal- 
cules, the  stem  of  the  latter  is  relatively 


604 


SYSTEMATIC  HTSTOllY  OP  THE  IXFFSORIA. 


thinner,  the  posterior  extremity  of  the 
sheath  pointed,  and  the  anterior  con- 
tracted. 

C.  curva  (Stein)  (xxx.  12)  resembles 
generally  a  contorted  specimen  of  C. 
Astaci ;  but  old  specimens  have  riisty- 
red-colom-ed  sheaths.  The  pedicle  of 
the  sheath  is  always  curved ;  the  anterior 
third  of  the  sheath  is  bent  outwards,  and 
the  posterior  half  ventricose,  particularly 
on  the  dorsal  surface.  The  bending  to 
one  side  causes  the  mouth  of  the  sheath 
to  be  oblique.  The  contained  animal- 
cule agrees  generally  ^dth  that  of  the 
two  preceding  species.  Length  of  sheath 
1-360".  Upon  the  ova-lappets  of  Ento- 
mostraca. 

Stein  doubts  the  independence  of  this 
species ;  for,  besides  being  imperfectly 
observed  by  Ehrenberg,  it  is  exceptional 


in  the  animalcule  not  being  fixed  at  the 
bottom  of  the  sheath. 

C.  Pupa  (Eichwald). 

Cpet^lqnda  (Bailey). — Apex  of  sheath 
attenuated,  slightly  curved;  surface  en- 
tirely covered  with  spirally  decussating 
rows  of  hexagonal  cells  ;  orifice  crenulate. 
Contained  animal  unknown.  St.  George's 
Bank  and  New  Haven  Harbour,  New 
York. 

C.  Floscidaria  (Perty). — Hyaline;  the 
cilia  of  frontal  segment  collected  in  tw^o 
groups,  recalling  thereby  the  aspect  of 
the  ciliary  apparatus  of  a  Floscidaria. 
Sheath  of  the  same  form  as  that  of  C.  im- 
herhis.  The  animal  lives  much  in  a  con- 
tracted state  ^\dthin  its  sheath,  and  ex- 
tends itself  very  slowly  :  on  the  contrary, 
the  act  of  contraction  is  rapid.  1-260". 
Among-  CaUitrichce. 


Genus  LAGENOPHPvYS  (Stein)  (XXX.  29-36).— Sheathed  VorticeUina, 
difiPering  especially  from  Cothurnia  and  Vaginkola  by  the  zooids  being  at- 
tached to  the  circumference  of  the  mouth  of  the  sheath,  and  freely  dependent 
from  it,  instead  of  being  affixed  to  the  bottom  as  in  those  genera.  The 
sheath  itself  is  without  pedicle,  and  adheres  to  foreign  bodies  by  one  side,  as 
does  that  of  Vaginkola  decumbens :  this  side  is  flattened,  and  may  be  referred 
to  as  the  abdominal  surface.  The  opposite  side,  or  the  back,  is  strongly 
vaulted.  The  mouth  of  the  sheath  is  very  much  narrowed,  and  furnished  with 
a  prominent,  flexible,  double  lip,  which  can  be  closed  when  the  contained  ani- 
malcule contracts  itself.  This  last  is  closely  adherent  by  its  peristom  wdthin 
the  margin  of  the  orifice  of  the  sheath,  and  has  generally  the  same  figure 
as  the  sheath,  but  not  the  same  dimensions ;  hence  it  lies  loosely  within  it. 
The  mouth  of  the  sheath  and  the  peristom  are  of  equal  diameter ;  and  through 
them  a  long  stalked  rotary  organ  projects,  terminated  by  a  circular  ciliary 
disc.  When  the  animal  contracts,  the  rotaiy  apparatus  is  withdrawn,  the 
peristom  closes  like  a  sphincter,  and  the  two-lipped  mouth  of  the  sheath  by 
its  closiu'e  completes  the  secimty  of  the  whole  being.  Reproduction  takes 
place  by  oblique  fission  and  by  gemmation. 

IjAGENOPHRYS  raginicola  (xxx.  29- 
36). — Sheath  elongated  cordaie ;  in  the 
centre  of  its  broader  and  truncate  end  is 
the  circular  orifice,  having  two  semi- 
circular, prominent,  valvular  processes, 
which  collapse  together  when  the  con- 
tained animalcule  contracts  itself.  The 
contracted  posterior  extremity  has  a  very 
thick  wall.  The  enclosed  animal  is  ovate, 
and  adherent  by  its  narrow  peristom  to 
the  orifice  of  the  sheath,  and  leaves  a 
large  interspace  posteriorly  between  itself 
and  the  enclosing  wall  of  its  sheath,  ex- 
cept when  it  retracts  itself.  The  young 
formed  by  gemmation,  as  well  as  the 
products  of  fission,  can  escape  only  when 
the  parent  being  loosens  its  attachment 
from  the  aperture  of  the  sheath,  and  so 
furnishes  an  outlet.    The  medium  length 


of  sheath  is  1-380" ;  the  gi'eatest  width 
1-640".     On  Cyclopsina  staphylina. 

L.  Amjndla.  —  Sheath  resembles  a 
plano-convex  circular  lens,  except  in 
having  an  anterior  projecting  everted 
rim  around  the  oral  orifice.  The  ani- 
malcule has  the  same  figure  as  the 
sheath,  and  an  internal  organization  like 
that  of  the  preceding  species.  Diameter 
from  1-480"  to  1-360".  On  aquatic 
animals,  Entomostraca,  and  the  like. 

L.  Nassa. — Very  similar  in  figure  and 
size  to  L.  Ampulla,  but  has  a  different 
profile  or  lateral  outline.  The  sheath^ 
although  nearly  spherical,  is  plano- 
convex, somewhat  truncate  in  front,  and 
emarginate  on  the  upper  surface,  as  is 
best  seen  in  profile.  The  mouth  of  the 
sheath  is  prolonged  as  a  cylindrical,  two- 


OF  THE  ENCHELIA. 


605 


lippedprocess,  capable  of  being  retracted.  I  occurs  on  G 
Is  more  rare  than  L.  Ampulla,  but,  like  it,  |  animals. 


contnarus 


and  other  aquatic 


Genus  LAGOTIA  (Wright)  (XXYin.  20-23 ;  XXXI.  7,  8).— Sheath  or 
case  retort-shaped,  with  a  cyliiidiical  neck,  plain  or  annulated ;  colourless, 
yellowish,  or  dark  green  ;  body  long,  cylindrical,  attached  by  its  posterior 
end  to  the  bottom  of  the  case,  terminated  anteriorly  by  a  forked  (furcate) 
head,  or  two  long,  flattened  ciliated  processes,  between  wliich  is  the  opening 
of  the  oral  cavity,  which  extends  backward  into  the  body  as  a  tapering 
oesophagus,  cihated  on  its  free  surface.  The  green  colour  of  the  body  in 
L.  viridis  is  not  due  to  dispersed  globules,  but  to  a  staining  of  the  sarcode 
itself.  Longitudinal  fission  has  not  been  seen ;  but  development  by  a  free 
ciliated  embryo,  very  unlike  the  parent,  has  been  observed  in  L.  ^roducta. 

Lagotia  viridis  (xxviii.  20-23).  —  I  L.  atro-purpurea. — Colour  of  animal 
Case  resembles  a  flask  or  amphora  l}ing  i  that  of  a  mixture  of  ink  and  water.  Cell 
on  its  side,  ha\'ing  the  neck  bent  more  |  yellowish-brown.  Probably  a  variet}'  in 
or  less  sharply  upwards,  and  dilated  into    colour  of  L.  viridis,  with  which  it  was 


a  trumpet-shaped  mouth.  Its  colour  is 
dark  sea-green,  in  the  larger  specimens 
nearly  opake.  Animalcule  green,  cylin- 
drical; its  ciliated  organ,  when  seen  in 
fi-ont  and  erect  (f.  23),  appears  like  a 
narrow  horseshoe  ;  whilst  from  the  side 
(f.  21)  the  anterior  extremity  of  the  ani- 
malcule bears  a  resemblance  to  the  head 
and  ears  of  a  hare — a  likeness  increased 
by  the  waggii 


iing  movements  of  the  long 
n  yoimg  specimens  the  lobes 
of  the   furcate   process    are   blunt   and 


the  cilia  are  aiTanged,  is  placed  at  a  little 
distance  from  their  margin  (f.  20),  instead 
of  being  close  to  it  (f.  22 j.  Plentifid  on 
marine  shells  and  Algae,  Firth  of  Forth 
and  T}Tiemouth.  Embryonic  develop- 
ment has  been  detected  by  Dr.  Wright 
in  this  species. 

L.  hyaliniL — Colourless  ;  lobes  of  cili- 
ated organ  wider  and  blunter  than  those 
of  i.  viridis ;  cell  buried  in  the  substance 
of  the  shell  oi  Alcyonidium  hirsutum,  and 
therefore  not  seen.  Granton  and  Queens- 
ferrv. 


found. 

L.  producta  (xxxi.  7-13)  (Dr.  Wright 
in  lit). — Neck  of  sheath  exceedingly  pro- 
longed, annulated ;  sheath  of  a  pale  yel- 
low-bro\^^l  colour.  Animalcide  (zooid) 
two  or  three  times  the  length  of  the 
sheath,  attenuated  ;  ciliated  lobes  erect, 
divergent,  and  recurved  at  tips ;  colour 
of  zooid  deep  blackish  green. 

Dr.  Wright  observed  the  development 
in  this  species  of  ciliated  embryos,- which, 
after  passing  through  the  stages  seen  in 
figs.  9  and  11  (xxxi.),  and  carrpng  on 
an  active  existence  as  free  ciliated  ani- 
malcules, form  an  attachment  to  some 
surface  and  proceed  to  develope  a  sheath 
and  the  characteristic  ciliary  lobes.  The 
transformation  from  ciliated  embryos  to 
Lagotice  transpired  in  the  course  of  a 
night,  —  the  sheath  even,  dm-ing  that 
time,  being  completed  with  its  rings.  The 
above  fact  constitutes  an  interesting  ad- 
dition to  the  illustrations  of  embryonic 
development  among  Ciliata,  quoted  in 
the  section  on  that  subject  (p.  353). 


FAMILY  Y.— EXCHELIA. 

Animalcules  having  a  distinct  alimentary  canal,  with  an  oral  and  an  anal 
orifice  at  the  opposite  ends  of  the  body ;  without  lorica.  Locomotion  eflected 
by  vibratile  cilia  in  all  the  genera  except  three,  viz.  Actinophrys,  Tricho- 
discus,  -dnd  Podojyhry a,  in  which  it  is  performed  by  slow-moving  feelers  (ten- 
tacles). In  all  but  these  exceptional  genera,  organs  of  nutrition  have  been 
demonstrated  by  the  employment  of  coloured  food ;  but  only  in  one  has  the 
entire  course  of  an  alimentary  canal  been  traced,  though  in  most  its  transit 
through  the  body  is  indicated  by  its  discharge  through  the  posterior  outlet. 
Ehrenberg  states  that  the  polygastric  structiu-e  is  to  be  seen  in  all  the  genera 
except  the  Arabian  genus  Disoma.  A  nucleus  and  vesicle  are  generally  present. 
Complete  self- division,  both  longitudinal  and  transverse,  has  been  observed ; 
but  not  gemmation.  The  most  curious  animalcules  among  them  are  the 
double-bodied  Disoma  and  the  teeth-bearing  Prorodon. 


606 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


The  genera  are  distributed  as  follows : — 


Surface     of 
body  desti- 
tute  of  Yl-i 
bratile 
cilia     .... 


Direct 
truncated 
mouth 
(no  lip) . . 


^  Yibratile       f  Body  simple    Enchelys. 

cilia  at  the  < 

mouth     ...  I  Body  double    Disoma. 


Eay-like 
tentacula 
not    yibra- 
tile   


r  The    body    co-U^^.^^^^j 
Stalkless       ^eredwithraysj 

\  Eays  at  the  edge  Trichodiscus. 
^  Stalked    Podophrya. 


No  neck  Trichoda. 


Oblique 
truncated 

i   rrflip)   I  With  neck  Lacrymaria. 


Sm-face     of 
body    with 
vibratile 
(^  cilia     _ 


Oblique  truncated  mouth,  with  lip Leucophrys. 

Direct  truncated  mouth,  no  lip    Holoplu*ya. 


Teeth  present Prorodon. 

In  the  arrangement  of  Dujardin,  and  under  his  fom^th  order — comprehend- 
ing '^  ciliated  Infusoria  without  a  contractile  integument,  and  with  or  without 
a  mouth  " — a  family  having  a  similar  name,  Enchelina  (Enchelyens,  so- 
caUed  after  a  genus  Enchelys)  is  instituted.  But,  most  unfortunately  for 
science,  this  family  and  this  genus,  with  respect  to  the  animalcules  they 
include,  in  no  way  correspond  with  the  similarly-named  family  and  genus 
of  Ehrenberg.  This  is  remarked  by  Dujardin  himself ;  and  he  adds,  with 
reference  to  the  genus  EiicJiehjs  (Ehr.),  that,  in  the  whole  course  of  his  ob- 
servations, he  never  met  Avith  any  Infusoria  bearing  the  characters  attributed 
by  Ehrenberg  to  that  genus,  and  he  is  led  to  conclude  that  the  beings  intended 
are  Paramecia  with  a  terminal  mouth,  or  else  Bursarice  imperfectly  examined, 
and  the  cilia  of  the  sui'face  overlooked. 

The  family  Enchelina  is  thus  briefly  characterized  by  Dujardin  : — "  Animals 
partially  or  entirely  covered  with  cilia,  dispersed  over  the  sui'face  irregularly ; 
mouth  wanting." 

The  family  Cyclidina  (Ehr.)  seems,  indeed,  much  more  nearly  allied  to  the 
Enchelys  of  Dujardin ;  but  its  characters,  as  given  by  Ehrenberg,  are  not 
sufficiently  definite  to  attempt  an  identification. 

Stein  severely  blames  Dujardin  for  the  transposition  of  generic  names  he 
has  been  guilty  of  in  the  case  of  this  genus  and  Cyclidium ;  for,  as  he  justly 
observes,  it  is  a  proceeding  productive  of  confusion  and  error.  The  Enchelys 
noclulosa,  he  adds,  is  the  CycJicUum  Glaucoma  (Ehr.),  and  scarcely  distin- 
guishable from  E.  triquetra  (Buj.).  Acomia  Ovulmn  seems  nothing  else  than 
Cyclklium  Glaucoma,  and  Uronema  marina  another  closely-allied  form,  and, 
liiie  Glaucoma  itself,  the  embryo  of  some  other  animalcule.  The  three 
remaining  species  of  Enchelys  enumerated  by  the  French  writer,  viz.  E.  cor- 
rugata,  E.  subangulata,  and  E.  ovata,  are  so  imperfectly  observed  as  to  be 
worthless,  and  their  union  in  the  same  genus  with  Glaucoma  quite  unwar- 
rantable. 

Yet,  if  Dujardin  has  proceeded  very  incautiously  in  rejecting  the  En- 
chelia  of  Ehrenberg  and  in  redistributing  its  genera,  no  apologist  of  the 
BerHn  naturalist  would  contend  that  it  should  be  left  as  it  is;  for  every 
person  having  any  acquaintance  with  the  beings  brought  together  as  En- 
chclia  Aivill   be   struck  with  their  heterogeneous  characters.     ActbiophrySf 


OF  THE  ENCHELIA.  607 

TricliodisGus,  and  Podophrya  belong  evidently  to  a  type  of  beings  altogether 
different  from  the  ciliated  animalcules  inchided  in  the  family ;  and  we  have 
consequently  treated  them  as  an  entirely  separate  group  from  the  ciliated 
Protozoa  in  our  general  history,  and  have  hkewise,  in  the  present  j)ortion 
of  the  work,  given  their  systematic  descriptions  apart.  The  genus  Disoma 
is  a  very  doubtful  member  of  this  family,  and  is  even  marked  as  such  by 
Ehrenberg,  who  had  very  imperfectly  examined  it. 

The  family  Enchelia  does  not  enter  into  the  system  of  Perty,  who  disperses 
its  members  among  different  families  according  to  his  appreciation  of  their 
several  affinities.  Among  the  rest,  his  family  "  Tapinia"  includes  some  species 
of  Leucoj^hrys  of  Ehrenberg  and  the  genus  Acomia  of  Dujardin,  along  with 
several  newly-constructed  genera,  the  account  of  which  will  be  annexed  to 
this  present  group. 

The  Family  "  Tapinia  "  is  thus  characterized : — 

"  Cilia  scattered  at  large,  or  collected  in  groups,  but  not  arranged  in  rows. 
Animals  mostly  very  small.  Mouth  not  apparent,  but  its  j)resence  revealed 
by  the  admission  of  food."  This  group  includes  the  genera  Acrojnsthiumy 
Acomia,  TricJioda  (Duj.),  Leucophrys  (Ehr.  ?),  Cyclidium,  Bceonidmm,  Opis- 
thiotricha,  Siagontherium,  and  Megatricha. 

Another  allied  family,  called  "  Apionidina,"  contains  a  species  of  Leuco- 
pJirys  (Ehr.).  Perty  assigns  it  the  following  characters : — "  Family  Apioni- 
dina :  Body  small,  soft,  thicker  at  one  end  than  the  other ;  cilia  in  longi- 
tudinal rows ;  mouth,  where  visible,  situated  at  the  anterior  end."  The  genera 
comprised  are  Pty.vidium,  Colobidmm,  and  Apionidiiim.  The  first-named 
genus  has,  as  its  type,  the  Leucophrys  pyrifonnis  (Ehr.) ;  but  the  other  two 
are  advanced  as  new  genera,  founded  on  newly-observed  beings. 

Both  in  this  family  (Apionidina)  and  in  that  of  Tapinia,  several  supposed 
new  genera  are  established  by  Perty,  which,  to  render  our  compendium  com- 
plete, we  are  bound  to  notice  and  describe,  although  we  regret  to  record  such 
a  midtitude  of  genera  and  names,  as  we  feel  highly  doubtful  of  their  claim  to 
consideration  as  independent  beings. 

Genus  ENCHELYS  (XXYIII.  64,  72,  73).— Vibratile  ciha  upon  surface 
wanting ;  mouth  terminal,  truncated  (direct,  not  oblique),  devoid  of  teeth ; 
surrounded  by  a  wreath  of  cilia.  An  oesophagus  is  not  seen  except  during 
the  passage  of  food.  An  anus  is  found  in  all,  and  in  E.  Farcimen  a  contractile 
bladder.     Self-division  is  transverse  and  complete. 

Dujardin  defines  his  genus  Enchelys  as  having  a  cylindrical,  oblong,  or  ovoid 
bod}^,  covered  with  erect  uniform  ciHa,  iiTegularly  disposed. 

Cohn  (Siebold's  Zeitschr.  1851,  B.  iii.  p.  273)  treats  this  genus  as  synony- 
mous with  Enclielys  (Duj.),  and  believes  that  several  of  its  assigned  species 
are  not  independent  animalcules,  but  embryos  of  Loxodes,  Oxytricha,  and 
allied  genera. 


Enchelys  Pupa  (M.)  (xx^t:ii.  72,  73). 
— Tm-gid,  chib-sliaped,  attenuated  an- 
teriorly ;  filled  with  gTeenish  vesicles,  or 
only  with  molecules  ;  neither  a  nucleus 
nor  a  vesicle  could  be  found  by  Ehren- 
berg. Ehrenberg  has  figm-ed  (in  his 
large  work  of  1838)  the  presumed  form 
of  tlie  polygastric  nutritive  system  of 
this  species  separately,  stating  it  to  be 
remarkably  distinct.  Common  in  stag- 
nant bog-water.     1-140". 

^.Farcimen  {E. Farcimen  et  Vibrio  in- 
testinum,  M.)  (xxviii.  64,  a-k). — Smaller, 


more  cylindrical  and  slender  than  the 
preceding  ;  granules  whitish.  These 
creatures  prey  on  other  animalcides 
nearly  as  large  as  themselves,  which 
they  devour  entire ;  this  will  account 
for  "^  the  variety  of  forms  which  they 
assume,  and  which  require  an  observer 
to  be  very  watchful  and  cautious  before 
he  can  pronounce  on  the  identity  of  a 
species.  Ehrenberg,  by  patient  obser- 
vation^ saw  one  individual  undergo  a 
great  variety  of  forms  in  the  act  of 
swallowing  a  yoimg  Kolpoda   Cucidltis ; 


603 


SYSTEMATIC  HISTOKY  OF  THE  IN'FUSOEIA. 


illustrated  in  fig.  64,  a-k.  In  stagnant 
water.     1-430". 

E.  infuscata.  —  Oval  or  spherical  ; 
whitish ;  mouth  not  prominent,  encircled 
by  a  brownish  ring.  When  fed  with 
indigo,  numerous  vacuoles  become  filled. 
In  bog- water.     1-280"  to  1-240". 

E.  nehulosa   (M.).  —  Ovate,   hyaline ; 


mouth  projecting.  This  species  receives 
caraiine  and  indigo  very  readily.  1-230" 
to  1-570".  '    ■ 

E.  nodulosa  {J)\\y^  •=  Cyclidium  Glau- 
coma (Ehr.).  E.  triquetra  (Duj.)  is  a 
mere  accidental  variety  of  the  same 
animalcule. 


Genus  DISO!MA  (?). — Body  double,  destitute  of  cilia  ;  oral  extremity 
truncated  (direct) ;  mouth  ciliated,  devoid  of  teeth.  Within  the  bodies 
numerous  little  vesicular  cells  (stomachs)  are  observed,  and  the  discharge  of 
excrement  may  be  seen  to  take  place  at  the  posterior  extremity  of  each  body. 

As  already  noticed,  this  is  a  very  imperfectly-examined  and  doubtful 
genus.  The  being  described  may  be  interpreted  as  one  undergoing  longitu- 
dinal fission  ;  but  there  is  no  one  character  given,  adequate  to  determine  to 
what  family  of  animalcules  it  would  be  referable. 


DisoMA  vacillans  consists  of  two 
clavate  and  filifonn  corpuscles,  hyaline, 
and  attenuated  at  the  anterior  extremity. 
Ehrenberg  remarks,  *'  Both  bodies  fre- 
quently swam  parallel  beside  each  other, 
and  turned  on  their  long  axis,  moving 


onwards  quickly,  though  in  a  vacillating 
manner ;  sometimes  both  bodies  gaped 
widely  apart  from  each  other,  but  never 
so  ^^ddely  as  to  form  a  straight  line. 
1-380".  '  On  Mount  Sinai,  Arabia. 


Genus  TRICHODA. — Body  devoid  (?)  of  hairs  or  cilia :  without  a  con- 
striction or  neck;  mouth  obliquely  truncated,  destitute  of  teeth,  but  pro- 
vided Ts-ith  vibratile  cilia,  and  a  Kp.  Coloiu'ed  food  is  received ;  the  anal 
orifice  is  at  the  posterior  extremity.  The  oblique  direction  of  the  mouth 
gives  rise  to  a  very  characteristic  upper-lip-like  projection.  In  T.  Pijrum 
only  has  self-division  been  observed.     All  the  species  are  coloiuiess. 

In  the  system  of  Dujardin  there  is  both  a  family  Trichodina  and  a  genus 
I'richoda.  Spealdng  of  the  relations  between  them  and  the  genus  Triclioda 
of  Ehrenberg,  he  observes  :  "  M.  Ehrenberg  has  placed  in  his  family  Enchelia 
a  genus  Triclioda,  which  in  part  corresponds  with  ours ;  and  he  has,  besides, 
dispersed  among  Leucoj^hri/s,  Encheli/s,  Trachelius,  Loxodes,  <S:c.,  many  Infu- 
soria which  we  have  brought  together  in  this  family  (viz.  Trichodina) ;  but, 
unlike  him,  we  are  unable  to  see  their  digestive  organs." 

The  Trichodina  are  soft,  variable,  flexible  animalcules,  ciliated,  and  have 
either  an  evident  mouth,  or  one  indicated  by  a  varpng  arrangement  of  longer 
cilia.  Dujardin  would  have  it  understood  that  this  family  is  only  pro\asional ; 
to  comprise  a  tribe  of  animals  intermediate  in  organization  between  the 
Enchelina — the  most  simple  of  ciliated — and  the  Keronina,  which  conduct  to 
the  highest  forms  of  infusorial  life,  having  defined  mouths,  and  an  armature 
of  styles,  hooks,  &c.  The  genera  included  by  Dujardin  in  this  family  are 
Triclioda,  Trachelius,  Acineria,  Pelecida,  and  Dileptus ;  the  last  two  having  a 
higher  grade  of  organization.     The  first-named  is  thus  described : — 

Genus  Triclioda  (Duj,). — Ovoid-oblong,  or  pyriform,  rather  flexible  ante- 
riorly, \nih.  a  row  of  cilia  directed  backwards,  and  appearing  to  indicate  the 
presence  of  a  mouth.  Their  surface  does  not  appear  reticulated,  or  ciliated  in 
rows,  as  it  is  in  Acomia  and  Encliehjs.  The  Triclioda  are  chiefly  found  in 
putrid  infusions  and  in  stale  marsh-water. 

TmcHODA  pura  (Kolpoda  Pyrum,  1  sions ;  usually  with  Cyclidium  Glaucoma. 
M.).  —  Oblong,     club-shaped,     attenu- I  1-720". 

ated   anteriorly ;   mouth   laterfd  ;   vacu-  i      Tliis  species  closely  resembles  Leiico- 
oles  small.     Common  in  vegetable  infu-  I  phrys  pyriformis,   which    is   somewhat 


OF  THE  ENCHELIA. 


609 


larger  and  ciliated  throughout.  How- 
ever, the  reality  of  T.  pura  as  a  species 
is  very  doubtful, — the  small  size  of  the 
vacuoles,  the  feature  most  relied  on  by 
Ehrenberg  as  distinctive,  being  in  reality 
not  at  all  so,  but  prone  to  great  varia- 
tions, determined  by  surrounding  cir- 
cumstances. It  swims  slowly,  revohdng 
as  it  proceeds. 

T.  Nasamomum.  —  Cylindrical,  extre- 
mities equall}^  obtuse,  mouth  large,  and 
elongated  laterally.     1-288". 

T.  omta. — Ovate,  tm'gid,  attenuated 
anteriorly;  mouth  small  and  lateral. 
1-480". 

T.  (?)  jEthio2nca. — Oblong,  attenuated 
posteriorly ;  under  side  flat  ;  mouth 
large.     1-600". 

T.  Asiatica. — Oval,  oblong,  cylindrical, 
roimded  at  both  ends ;  mouth  small. 
1-860". 

This  species,  together  with  the  three 
immediately  preceding,  must  be  regarded 
as  doubtful;  for  they  were  merely  casually 
examined  by  their  discoverer  whilst  tra- 
velling, and  when,  as  we  must  suppose, 


he  had  neither  the  means  of  comparing 
the  beings  with  others  akin  to  them, 
nor  very  favourable  opportunities,  in  the 
rough  accommodation  of  desert  tra- 
velling, for  careful  microscopic  examina- 
tion. 

T.  Pyrum  (Kolpoda  Pyrum,  M.). — 
Ovate,  tiu'gid,  acute  anteriorl}' .  Amongst 
Confervse  on  Mount  Sinai.     1-1200". 

A  species  with  this  name  is  also  men- 
rioned  by  Dujardin  {i&  =  KoIpoda  Pyrum  ? 
(Miiller).  It  is  thus  described : — "  Body 
ovoid,  oblong,  narrowed  anteriorly,  or 
pja'iform ;  thicker  in  one  direction  than 
in  the  other;"  and  he  goes  on  to  say 
that  this  is  the  same  being  as  the  Leu- 
cophrys  carnium  (Ehr.). 

T.  anyulata  (Duj.). — Oblong,  obliquely 
and  regularly  plaited  or  angular,  often 
with  one  or  more  superficial  vacuoles. 
1-900". 

T.  Lynceus. — The  animalcule  described 
under  this  name  is  (sa^'s  Cienkowsky) 
probably  no  other  than  the  young  phase 
of  various  Oxytriclice  and  StylonycMce 
(Siebold,  Zeitsch.  1855,  vol.  vi.  p.  301). 


Genus  LACRYMAMA  (XXIV.  274,  275).— Body  with  a  long  narrow 
neck,  slightly  enlarged  near  the  termination,  where  is  situated  the  ciliated  and 
lateral  (lipped)  mouth,  destitute  of  teeth.  Body  not  ciliated.  Locomotion  is 
performed  by  means  of  the  neck,  the  distensible  body,  and  the  oral  cilia.  The 
proboscis-like  lip  is  very  short,  sometimes  distinctly  articulated,  and  projects 
but  little  beyond  the  oral  orifice.  Coloured  food  is  received  by  L.  Proteus, 
and  its  discharge  may  be  seen  to  take  place  from  the  posterior  extremity  in 
one  species ;  in  another,  green  granules  (ova)  are  present. 

The  genus  Lacrymaria  of  Dujardin  agrees  mainly  with  that  just  defined  ; 
but  the  French  author  differs  entirely  from  Ehrenberg,  by  stating  that  the 
Lacrymarice  are  distinctly  ciliated  on  their  surface,  and  that  the  cilia  are 
disposed  in  regular  series  among  the  reticulations  of  the  integument. 

Dujardin,  in  his  notes  on  Lacrymaria,  has  some  very  just  obsei'vations  on 
the  relation  between  this  genus  and  the  Phialina  and  TracJielocerca  (Ehr.). 
He  says,  the  species  of  Lacrymaria,  which  Ehrenberg  noticed  to  be  generally 
not  ciliated  on  the  body,  have  been  classed  by  him  according  to  the  relative 
position  of  the  mouth  and  anus, — some  among  theEnchelia,  others,  as  Phialina, 
among  the  Trachelia,  and  others  again  in  the  genus  Trachelocerca,  the  type 
of  his  family  Ophryocercina.  On  this  plan,  Lacrymaria  has  the  body  without 
cilia,  prolonged  into  a  narrow  neck,  terminated  by  an  obliquely  tiimcate  and 
ciliated  mouth,  at  the  opposite  extremity  to  which  is  the  anus ;  Phialina 
similar,  except  that  the  neck,  instead  of  being  terminated  by  a  simple  enlarge- 
ment, is  notched  on  one  side,  and  the  mouth  therefore  lateral ;  and  Trache- 
locerca, which  he  himself  caUs  "  tailed  Lacymarice,''  have  a  terminal  mouth, 
and  an  anus  on  one  side  in  advance  of  a  conical  caudiform  prolongation  of  the 
body.  These  distinctions  are  not  borne  out  by  more  critical  investigations, 
and  at  most  are  insufficient  to  establish  generic  characters,  and  still  more 
those  of  higher  groups  or  families.  As  the  result  of  these  considerations, 
Dujardin  has  comprehended  all  the  species  distributed  in  the  three  genera 
named  in  one,  \dz.  Lacrymaria,   which  he  places  among  the   Paramecina. 

2r 


610 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


The  doubt  expressed  concerning  the  existence  of  a  mouth  as  described  by 
Ehrenberg,  has  been  removed  by  later  observations. 

The  variability  of  form  of  which  the  Lacrymarice  are  capable  was  noticed  by 
Baker  and  other  old  observers,  and  suggested  the  appellation  Proteus,  origiaally 
bestowed  on  them.  Perty  has  made  use  of  this  peculiarity  to  constitute  a 
section  of  Cihated  Protozoa,  which  he  has  named  "  Metabolica."  Besides 
Lacn/maria,  it  includes  TracJielocerca,  these  two  genera  being  combined  into 
a  faroily,  ''  Ophiyocercina."  His  genus  TracJielocerca,  however,  is  not  equi- 
valent to  the  one  so  named  by  Ehrenberg,  since  it  also  comprises  the  species 
of  Pliialiim  enumerated  by  that  author.  This  employment  of  a  recognized 
systematic  term  with  a  wider  signification  than  that  originally  given  to  it, 
cannot  be  commended ;  and,  as  Perty  makes  no  attempt  to  define  the  differ- 
ential characters  between  the  two  genera  as  understood  by  himself,  we  regard 
his  family  Ophryocercina  as  imsatisfactory.  The  Phialince  he  considers  only 
young  or  contracted  examples  of  one  or  other  genus.     (See  Phialina  and 

TjiACHELOCEECA.) 

nor  an  enlargement  is  observ^able  near 
the  mouth.  1-570":  including  neck, 
1-288". 

L.  versatilis  (Duj.)  (^TricJwda  vei'satilis, 
M.). — Fusifonn ;  neck  retractile^  ciliated 
beneath,  shorter  than  in  L.  Proteus,  which 
it  is  fm'ther  imlike  by  having  the  body 
pointed  posteriorly,  and  by  living  in  sea- 
water. 

Perty  declares  this  is  not  an  independ- 
ent species,  but  only  the  immatm-e  fonn 
of  Trachelocerca  Olor  (Ehr.). 

L.  tornatilis, — Neck  retractile,  some- 
times disappearing  entirely,  presenting 
then  only  the  cilia  crowning  its  exti'e- 
mity. 

L.  farcta. — Flask-shaped,  with  a  short 
neck.  In  ditch-water  about  Paris. 
1-260". 


Lacry]maria  Proteus  (TricJioda  Pro- 
teus, M.)  (xxiv.  274, 275).— Oblong,  tm-- 
gid,  with  delicate  transverse  folds.  Colour 
varies  from  grey  to  green.  The  neck  is 
capable  of  considerable  extension.  It 
resembles  Trachelocerca  Olor;  but  its 
posterior  extremity  is  rounded,  and  has 
at  its  centre  the  discharging  orifice.  Re- 
productive organs  unknown.  Amongst 
Lemn?e.     Size  stretched  out  1-140". 

L.  Gutta. — Body  smooth  and  nearly 
spherical,  with  a  very  long  neck.  Perty 
discovered  a  tongue-like  process  above 
the  mouth  in  some  examples.  Among 
Confervae.  Size  1-1150"  j  including 
neck,  1-210". 

L.  rugosa.  —  Nearly  globidar,  and 
wrinkled ;  the  neck  of  medium  length ; 
granules  green.  In  swimming,  it  often 
revolves  on  its  long  axisj  neither  cilia 


Genus  LEUCOPHRYS  (XXIV.  276,  277,  278,  279,  280).— Covered  with 
vibratile  cilia ;  mouth  obhque,  terminal,  without  teeth.  From  the  obhquity 
of  the  mouth,  there  is  the  appearance  of  an  upper  lip.  The  cilia  which  cover 
the  body  are  short  and  disposed  in  rows ;  those  aroimd  the  mouth  are  longer, 
and  produce  very  powerful  ciu-rents.  In  swimming,  aU  the  species  revolve 
upon  the  longer  axis.  A  serpentine  alimentary  canal,  with  more  than  fifty 
grape-like  stomach-cells  (XXIV.  276),  terminating  at  the  opposite  extremity 
to  the  mouth,  is  described  by  Ehrenberg ;  in  some,  one  or  two  globidar  nuclei 
and  a  contractile  vesicle  are  seen.     Self- division  transverse  and  longitudinal. 

Leucoplirys  forms,  in  the  system  of  Dujardin,  with  Sj)athiclium  and  Opalina, 
the  family  ^'  Leucophryens,"  characterized  by  having  "  an  oval  or  oblong  de- 
pressed body,  covered  Avith  cilia  densely  but  regularly  disposed ;  mouth  not 
evident ;  foreign  solid  particles  are  not  to  be  found  in  the  vacuoles ;  hence 
probably  these  animals  hve  only  by  absorption.  Most  of  them  are  parasitic 
TN-ithin  Annehda  and  Batrachia,  and  soon  perish  in  pure  water,  like  Helmin- 
thoid  (tape)  worms."  Dujardin  says,  ^'  It  is  to  the  genus  Bursaria  that  Ehi'en- 
berg  has  transferred  most  of  the  true  Leucophryens,  in  conjunction  with 
other  Infusoria  ha\4ng  a  very  distinct  mouth,"     (See  Opalin^a,  p.  569.) 

Dujardin's  characters  of  Leucophrys  are : — "  Body  depressed,  oval  or  oblong, 


OF  THE  ENCHELIA. 


611 


equally  rounded  at  the  two  ends,  covered  by  long,  very  numerous,  vibratile 
cilia,  in  parallel  rows  ;  no  mouth.  I,"  says  Dujardin,  "  have  restricted  the 
term  to  animalcules  parasitic  within  Lumhric'i,  but  ought  probably  to  include 
the  form  met  with  by  Ehrenberg  in  the  AnodontceJ^ 

This  genus  requii^es  further  examination,  and  may  probably  be  cancelled 
by  the  transfer  of  its  members  to  other  groups.  It  is  certain  that  several  of 
its  enumerated  species  are  mouthless,  and  that  some  belong  to  the  Opalinaea ; 
and  Dujardin  clearly  pm^sued  a  very  right  course  in  detaching  it  from  the 
heterogeneous  class  Encheha,  and  in  bringing  it  into  relation  with  Opalina. 
Perty  has  followed  a  similar  plan,  and  instituted  a  family  of  parasitic  animal- 
cules under  the  name  of  Cobalina,  comprehending  besides  Leucojyhri/s  (repre- 
sented by  only  one  species,  L.  striata)  Opalina,  Plagiotoma,  and  Alastor. 
Like  Dujardin,  also,  he  transfers  L.  patuJa  to  Bursaria ;  treats  L.  Spatliida 
as  identical  with  Spathidium  liyaUnum  (Duj.),  but  places  it  in  a  family 
Holophi^yina,  along  with  Holophrya  and  Enchehjs  (i.  e.  as  represented  by 
E.  Farcimen  and  E.  Pupa).  Neither  Ehrenberg's  descriptions  nor  figures 
are  sufficient  to  identify  L.  sanguinea  either  with  Bursaria  or  Opalina ;  its 
colour  lends  no  aid,  since  it  is  doubtless  accidental.  L.  p>yriformis  and  L. 
carnium  are  doubtful  members,  and  the  rest  named  are  petty  clearly  Opalinaea. 
L.  carnium  is  treated  by  Dujardin  as  identical  with  TricJioda  carnium. 


Leucophbys  patuJa  (  Triclioda  patula, 
M.)  (xxiv.  276,  277)  {Bursaria  patula, 
Duj.).  —  Oval,  campanulate,  turgid; 
sometimes  quite  pellucid,  at  others 
whitish ;  mouth  ample  and  gaping ; 
vacuoles  are  very  large,  and  fill  them- 
selves with  food  in  an  irregular  manner. 
When  (says  Ehrenberg)  the  animalcide 
is  quiet,  the  passage  of  the  food  onwards 
is  seen  in  the  serpentine  canal,  to  which 
the  stomachs  are  attached  like  benies ; 
even  the  stalk  or  short  communicating 
tube  is  visible  when  they  receive  or  dis- 
charge colom-ed  food.  The  longitudinal 
rows  of  cilia  are  very  nimierous  in  full- 
grown  specimens.  The  gTanules  are 
white  by  incident  light,  brownish  by 
ti'ansmitted.  In  the  middle  of  the  body 
is  a  small  globular  nucleus.  Both  in 
fresh-  and  sea- water.     1-280"  to  1-96". 

L.  Spathida  ( =  Enchelys  Spathula, 
M.)  (xxiv.  278).  —  Lanceolate,  com- 
pressed, whitish :  mouth  narrow,  situated 
at  its  anterior  extremity,  which  is  ob- 
liquely truncated  and  membrane-like. 
Amongst  Lenmae.  1-140".  Vide  Spa- 
THTDiLTM  hyalinum,  p.  612. 

L.  sanguinea  {Triclioda  striata,  M.) 
(xxiv.  279,  280).— Cylindrical,  rounded 
at  both  extremities,  and  of  the  colour  of 
blood.  Ehrenberg  remarked  within  it 
two  bright  contractile  romid  bladders, 
and  that  on  seh-di^dsion  one  was  present 
in  each  part.     1-144". 

^.pyriformis  (Koljjoda  Pyrwn,  M.). — 


Ovate,  whitish,  rather  more  acute  ante- 
riorly ;  vacuoles  large.  1-570"  to  1-280". 

Dujardin  considers  that  this  species 
should  rightly  be  transferred  to  Glaucoma 
or  Kolpoda. 

L.  carnium  {Kolpoda  Pyrum,  M.). — 
Oval,  oblong,  acute  anteriorly,  and  of  a 
whitish  colom*;  vacuoles  narrow.  In 
putrescent  annual  water,  and  the  drain- 
age of  mamne.  1-1440"  to  1-430".  It 
=  TricJioda  Pyrum  (Perty). 

Perty  suggests  that  Enchelys  nodulosa 
is  referable  also  to  this  species. 

L.  (?)  Anodontcs  {Leucophra  jlidda, 
M.).  —  Oval,  tm'gid,  and  transparent ; 
roimded  at  both  extremities.  In  Siberia 
and  at  Copenhagen.  1-430".  Most  pro- 
bably it  is  an  Opalina. 

L.  striata  (Duj.). — Oblong,  marked  by 
thirty-five  longitudinal  granular  striae. 
1-325"  to  1-200".  In  the  Liimhrici 
(worms)  of  gardens. 

This  is  the  only  species  of  Leucophrys 
retained  by  Perty.  On  the  other  hand, 
Stein  (p.  184)  asserts  that  it  is  an  Opa- 
lina, a  mouthless  animalcule,  and  there- 
fore rightly  excluded  from  Enchelia. 

L.  nodulata  (Duj.). — Oblong,  regidarly 
ciliated ;  without  distinct  striae,  but  hav- 
ino;  two  series  of  vacuoles.     In  Lumbrici. 

The  last  three  supposed  species  are, 
says  Stein  {Infus.  p.  184),  Opalince,  and 
the  last  two  should  be  imited  as  one, 
which  may  be  named  O.  Lumbrici.  (See 
family  Opalix^ea,  p.  569.) 


Genus  SPATHIDIUM  (Duj.)  (XXYI.  27).— Oblong;  thicker  and  more 
rounded  behind  ;  thinner,  expanded,  and  truncated  in  front. 

2v.2 


612 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


This  genus  is  admitted  by  Perty,  who  places  it  in  the  family  "  Holophmna," 
but,  unlike  Dujardin,  beheves  it  to  possess  a  mouth. 


Spathiditjm  hyalinum  (xxvi.  27).  — 
Oblong,  lanceolate,  hyaline ;  thin  and 
almost  membranous  anteriorly,  and  ter- 
minated by  an  oblique  margin,  along 
which  some  small  black  nodules  may  be 
seen.  In  pond-water,  near  Paris.  The 
Enchelys  SpatJuda  of  Miiller  would  seem 
to  be  the  same  species;  but  the  Letr- 
cophnjs  Spathula  (Ehr.)  differs  from  it 
in  having  a  row  of  cilia  on  the  ante- 
rior margin,  with  striae   on   each  side, 


and  in  receiving  indigo  in  its  stomach- 
sacs. 

Perty,  however,  treats  them  as  identi- 
cal. Indeed,  the  marks  of  distinction 
Dujardin  would  draw  are  certainly  in- 
sufficient to  establish  a  specific  differ- 
ence ;  since  the  absence  or  presence  of  a 
row  of  cilia  may  readily  be  unobserved, 
and  the  reception  or  non-reception  of 
indigo  is  very  mucli  a  matter  of  manipu- 
lation. 


Genus  HOLOPHRYA  (XXIV.  281).— Ovoid,  oblong,  or  even  cylindiical; 
covered  with  ^ibratile  cilia ;  mouth  anterior,  directly  truncated  or  terminal, 
and  without  lip  or  teeth.  In  two  species  the  mouth  and  anus  have  been  seen. 
Cilia  disposed  in  longitudinal  rows.  In  H.  Ovum  green  granules  and  a  posterior 
contractile  vesicle  are  observable ;  self-division  appears  to  be  transverse  in 
H.  discolor. 

In  the  system  of  Perty,  Holophrya  gives  name  to  a  family  "  Holophryina," 
defined  as  having  ''  an  anterior  mouth,  a  posterior  anus,  and  the  surface 
covered  with  cilia  in  longitudinal  rows."  It  includes  the  genera  Holophrya, 
some  species  of  Enchelys  and  S^athiclium  (Duj.),  LeucopJirys  (E.).  The  two 
species  of  Enchelys  mentioned  are  E.  Farcimen  and  E.  Pupa  ;  the  LeucopJirys 
is  the  L.  Spathula  (Ehr.). 

Holoplirya  is  closely  allied  to  Prorodon ;  indeed  its  independence  is  very 
doubtful ;  for  the  only  distinctive  character  between  the  two  genera  put  for- 
ward is,  that  the  *'  dental  cylinder  "  is  absent  in  the  foimer ;  but  this  is  a 
structural  peculiarity  not  always  very  obvious  to  the  eye,  liable  to  be  over- 
looked, and  of  secondary  histological  importance. 

Holoplirya  and  the  following  genus,  Prorodon,  are  included  in  Dujardin's 
family  Paramecina. 


HoLOPHRYA  Ovum  {Leucoplira  hursata, 
M.)  (xxiv.  281).  —  Ovate,  somewhat 
cylindrical,  extremities  subtnmcate ; 
granules  green.  Amongst  Lemnse  and 
Conferva.     1-570"  to  1-210". 

H.  discolor  (Trichoda  horrida,  M.). — 
White,  ovate,  conical,  subacute  at  the 
posterior  extremity ;  cilia  long  and 
scattered.     Amongst  Confervae.   1-240". 

This  species  Stein  has  noticed  in 
the  encysted  condition,  surroimded  by 
a   thick-walled  cyst.     Cohn,  moreover. 


found  the  previous  species,  H.  Ovum,  in 
the  same  condition.  Instead  of  being 
white,  it  is  often  colom-ed  green  by 
chlorophyll. 

H.  Coieps  {Leucophra  glohulife)'a,  M.). 
— Oblong,  cylindi'ical ;  rounded  at  both 
extremities;  whitish.    1-430" to  1-280". 

H.  hrunnea  (Duj.). — Brown,  changing 
from  a  cylindrical  to  a  globular  form 
when  filled  with  food,  and  also  then 
altering  in  colour. 


Genus  PRORODOX  (XXIV.  282;  XXVIII.  8).— Is  distinguished  by  the 
directly  tnincated  mouth,  and  a  cii'clet  or  cylinder  of  internal  teeth.  Body 
covered  with  vibratile  cilia.  Digestive  cells,  an  oral,  and  an  anal  outlet  have 
been  demonstrated  by  coloured  food.  A  long  band-like  nucleus,  contractile 
sac,  and  granules  are  seen  in  P.  niveus. 

In  the  system  of  Perty,  Prorodon  constitutes  a  member  of  the  family 
Decteria,  in  company  with  Chilodon,  Nassula,  Hahrodon,  and  Cydograimm. 
Hahrodon  is  annexed  to  this  present  family ;  but  Oyclogramma  will  be  found 
placed  among  the  Trachelina,  along  with  Chilodon  and  Nassula. 


OF  THE  EXCHELIA. 


613 


Prorodon  tiiveus. — Large,  elliptical, 
and  compressed ;  colour  white ;  circlet  of 
teeth  compressed  (teste  Ehr.),  as  shown 
separate  in  xxiv.  283.  Smaller  examples 
have  fewer  teeth  than  the  large.  Cilia 
very  fine.  It  is  fomid  encysted.  Amongst 
Confervae  in  turf-pools.  1-72".  Cohn 
intimates  (Zeitschr.  1853,  iv.  p.  271)  that 
this  species  and  the  next  are  merely 
varieties  of  the  same  being. 

P.  teres  (xxiv.282j  xxvni.  8). — Ovate, 
cvlindrical,  white  ;  circlet  of  teeth  cylin- 
drical. Ehrenberg  coimted  twenty  sup- 
posed teeth  ;  and  when  the  cylinder  was 
broken,  forty-five.  Revolves,  in  swim- 
ming, upon  the  long  axis.  1-140".  It 
has  been  seen  in  the  encysted  state,  and 


to  undergo  fission  when  in  that  condition. 

P.  viridis. — Large,  elliptic,  compressed, 
gTeen,  with  a  nearlv  cvlindrical  crown  of 
teeth.     1-120".     Berlin. 

In  all  probability  this  green-coloui-ed 
organism  is  a  mere  variety  of  the  pre- 
ceding, from  which  it  offers  no  distinc- 
tive featm*es.  In  Prorodon,  as  in  CJd- 
lodon,  fission  occurs  in  encysted  beings. 

P.  vorax  (Perty). —  Hyaline,  seldom 
green  ;  dental  apparatus  faintly  marked. 
Integument  covered  with  wart-like  ele- 
vations in  rings.  Movements  tolerably 
rapid ;  oftentimes  oscillating.  Anus 
placed  at  posterior  extremity.  1-240" 
to  1-84".  It  chiefly  differs  from  P.  niveus 
by  its  faintly-marked  dental  apparatus. 


We  have  yet  to  append  some  genera  (whose  affinity  is  with  the  foregoing) 
described  by  Dujardin,  viz.  Acomia,  Gastrochceta,  Alyscum,  and  Uronema, — 
and  which,  vnth  the  genus  Enchelys,  constitute  his  family  Enchelyens 
(Enchelina). 

Acomia  and  Gastrochceta  are  only  ciliated  partially — the  former  at  one 
end,  the  latter  along  a  longitudinal  fiuTOW  on  the  under  surface.  Enchelys, 
Alyscum,  and  Uronema  are  ciliated  throughout, — the  first  having  but  one 
form  of  cilia ;  the  second,  cilia  together  with  some  long,  contractile,  trailing 
filaments ;  and  the  last,  cilia  T\ith  a  single,  straight  and  long  posterior 
filament. 

Genus  ACOMIA  (D.)  (XXVI.  16,  17). — Oval  or  irregular,  oblong,  coloui-- 
less  or  cloudy,  formed  of  a  homogeneous  glutinous  substance  containing 
unequal-sized  granules,  and  ciliated  at  one  end.     No  mouth. 

Perty  remarks  that  there  is  an  absence  of  definite  characters  between 
this  genus  and  the  Enchelys  (Duj.),  and  that  the  species  of  Acomia  require 
further  study. 


Acomia  CycUdium  (xxvi.  16  a,  b). — 
Oval,  oblong,  depressed,  containing  large 
granides  and  some  vacuoles  ;  transverse 
fission.  In  external  form  approaches 
Cylidimn  (Elir.).    Marine,     1-650". 

A.  vitrea  (xxvi.  17  a,  b). — Ovoid,  hya- 
line, but  rendered  cloudy  by  granules  in 
its  posterior  half ;  anterior  border  ciliated; 
division  longitudinal.  1-1250".  In  fetid 
water. 

A.  ovalis. — Differs  from  the  preceding 
bv  the  gi-anules  occup^dng  the  anterior 
half,  and  by  its  length,  1-868".  In  fetid 
marsh-water. 

The  difference  in  position  of  the  gra- 
nules is  valueless  as  a  specific  distinction 
between  this  and  the  previous  species, 
and  should  be  rejected. 

A.  Ovulnm. — Ovoid,  presenting  a  no- 
dular or  gi-anular  portion,  which  seems 
to  contract  itself  within  the  interior 
of  a  diaphanous  envelope.  Revolves  in 
moving,  like  a  Doxococcus.     1-300". 

Stein    (Iiifus.   p.   137)    declares  that 


it  is  undistinguishable  from  CycUdium 
Glaucoma  (Ehr.). 

A.  (?)  Vorticella. — Ovoid,  nearly  glo- 
bular, colourless,  cloudy ;  ciliated  in  its 
anterior  half;  cilia  curved  backwards. 
Revolves  on  its  axis  in  progressing  for- 
wards.    1-1000".     In  sea-water. 

A.  (?)  costata.  —  Ovoid-oblong,  nar- 
rower in  front ;  apparently  enclosed  by  a 
thick  membrane,  or  consistent  layer; 
nodular  ;  nodules  often  arranged  in  rows 
as  ribs.  Division  transverse.  1-650"  to 
1-500".     In  sea-water,  among  Algae. 

A.  varians.  —  Oblong,  cylindrical ; 
truncated  and  angidar  in  front ;  dilated 
and  compressed,  by  tiu-ns,  in  different 
parts  of  its  length,  and  consequently 
alternately  roimded  and  constricted  be- 
hind, so  as  to  teniiinate  by  a  pointed  tail. 
Revolves  on  its  axis.    l-l000"tQ  1-450". 

A.  injlata. — O^al,  tapering  anteriorly, 
beset  every^vhere  with  very  fine  cilia; 
colourless,  or  occupied  with  green,  grey, 
or  brown   granules.     Movement  rapid 


614 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


revolving:.  Cilia  often  appear  longer  in 
front.  Found  by  Dujardin  and  Perty  in 
decomposing  marsh-water. 

A.  cava  (Perty). — Oval,  sliglitly  iiTe- 


gular;  convex  above,  flat  beneath,  or 
rather  concave.  Thickly  ciliated  all 
over.     1-670".     Amongst  Lenmse. 


Genus  HABEODON  (Perty). — Body  subcyHndrical,  rather  bent ;  thickened 
posteriorly,  and  mostly  tnincate  in  front.  Mouth  anterior,  with  a  veiy  deh- 
cate  dental  apparatus.     Anus  posterior.     Cilia  in  longitudinal  rows. 

This  genus,  created  by  Perty,  is  placed  by  him  in  juxtaposition  with  Pro- 
rodon,  with  which  and  CliUodon,  Nassida,  and  a  new  genus,  Cydogramma, 
it  constitutes  a  family  called  Decteria. 


Habeodon  ciirvatus  =  Enchehjs  Pupa 
(?)  (Midi.). — Colour  usually  grey  or  pale 
green,  with  nmnerous  moleciiles  and 
vesicles;    anteriorly  it   is   hyaline,  and 


posteriorly  it    presents    a   round    clear 
space    (an   anus  ?).      Movements    slow. 


1-390"    to    1-132". 
Cliara,  &c./Bern. 


In   spiings,  with 


Genus  ACROPISTHIUM  (Perty)  (XXYIII.  61).- 
rior  flap,  or  rounded  o£P ;  pointed  behind. 

AcEOPiSTHiUM  mutabile.  —  Hyaline, 
with  darker  vesicles  and  molecules. 
Movements  very  rapid,  revolving.  Cilia 
cover  the  entire  surface,  very  fine,  usually 


-Cii'cular,  with  an  ante- 


more  perceptible  anteriorly.  The  figure 
varies  much.  Mouth  in  front  (?).  1-360" 
to  1-320".     Uncommon. 


Genus  BJEOIN^IDIUM  (Perty)  (XXYIII.  52-54).— Small,  subcylindrical ; 
cilia  at  anterior  end  large  ;  movement  sluggish. 

movement.     A  slight  depression  some- 


times perceptible  on  one  side,  in  the 
position  of  the  mouth.  Fission  trans- 
verse. 1-840"  to  1-660".  Amongst 
Charse,  but  rare,  in  Switzerland. 


B^oiSTTDiuiM  remigans. — Usually  pris- 
matic and  roimded;  often  rather 
wrinkled;  hyaline,  but  nearly  always 
filled  with  green  corpuscles.  Cilia 
generally  distributed  ;  the  large  anterior 
ones    simulate    pedal    organs  in    their 

Genus  OPISTHIOTBICHA  (Perty)  (XXYIII.  55-57).— Small,  elongated- 
cyUndiical  or  ppiform  ;  cilia  distributed  over  the  body,  very  fine,  some  of 
those  on  the  posterior  extremity  large,  ciliary  action  sluggish. 


Large  posterior  cilia  from  two  to  three 
in  voung  specimens,  five  to  six  in  old. 
1-900"  to  1-440".  In  marsh-  or  bog- 
water.    Bern,  &c. 


Opisthioteicha  tenuis  (xxvin.  55- 
57). — Colom-less  or  slightly  green,  with 
delicate  vesicles  and  molecules  in  the 
interior.  Swims  very  ra^idl}^,  revolv- 
ing at  the  same  time  on  its  long  axis. 

Genus  SIAGOIN'THEBIUM  (Perty)  (XXYIII.  62,  63).— Yery  small,  ex- 
tended anteriorly,  thickened  posteriorly ;  with  a  long  stiff  bristle  extended 
backwards  on  one  side  of  the  anterior  extremity. 

SiAGOXTHEEiUM  temie. — Seen  on  the  delicate,   with    internal    molecules  and 

wdder    side,  elongated    ovate;    anterior  vesicles.     Scarce  in  pools.     Bern,  with 

prolongation  directed  forwards  from  the  Hysginum  pluviale.     1-900"  to  1-760". 
smaller  subcylindrical  half.     Extremely 

Genus  MEGATRICHA  (Perty)  (XXYIII.  58-60).— Yery  smaU,  clothed 
with  long,  scattered  and  slowly-moving  cilia.  Body  entire,  or  divided  incom- 
pletely into  two  unequal  portions.  "  These  are  the  most  delicate  and  simple 
of  all  the  Ciliata." 

1-1440".    Un- 


Megateicha  Integra.  —  Undivided, 
colourless,  with  long,  delicate  cilia. 
Yery  possibly  Chcetomonas  Ghbuhfs  be- 


longs 


to   this   species, 
common. 

M.  imrtita  (xxvni.  68-60). 


-Divided 


OF  THE  ENCHELIA. 


615 


into  a  smaller,  rather  pointed,  anterior 
section,  and  a  vdder  posterior  one ;  co- 
loui'less.  Extremely  delicate;  often 
composed,  like  many  Monads,  of  only 
five    molecules.      Movements    of    cilia 


sluggish.  Swimming  often  interrupted 
suddenly  by  a  jerk  in  another  direction. 
Fission  longitudinal.  1-1560"  to  1-1320". 
Rare,  among  decomposing  Confervse. 


Genus  PTYXIDIUM  (Perty)  (XXYIII.  40-42). 
with  several  folds.     Cilia  equal,  very  fine. 

Ptyxtdium  Ovidum  —  Leucophn/s  pi/ri- 
fonnis  (Ehr.).  Kolpoda  Pyrum  (MiilL), 
which  Ehi-enberg  cites  as  synominous, 


-Ovate,  pointed  in  front. 


is  more  probably  an  Acomia.     Perty  dis- 
covered no  food  in  the  interior. 


Genus  COLOBIDIUM  (Perty)  (XXYIII.  45).— ^Tien  mature,  ovate;  in 
earlier  condition,  truncate  posteriorly — frequently  emarginate, — rounded  an- 
teriorly. Cilia  in  longitudinal  rows,  those  in  front  longer ;  their  movements 
slow. 

CoLOBiDiuMj9e//?/c^V7Mm. — Very  trans- 
parent, colourless  or  clear  gi-een ;  move- 
ments rapid,  always  rotating.  "  The 
longer  cilia  in  front  often  moved  in  a 


foot-like 


1900"  to  1-600". 
Bern. 


manner. 
In  tm-f-hollows  among  Confervse 
Acomia  Vorticella  (Duj.)  is  probably  only 
a  variety  of  this  species. 


Genus  APIONIDIUM  (Perty)  (XXYIII.  48,  49).— Rounded ;  thicker  in 
front  than  behind ;  rows  of  cilia  few  in  number. 

Apioxidiuim  modestum.  —  Hyaline, 
with  colom-ed  (green  or  brown)  food-par- 
ticles.  Rows  of  cilia  from  seven  to  nine ; 


cilia  very  fine.  A  round  clear  space 
usually  visible  posteriorly.  Rare.  1-260" 
to  1-240". 


Genus  GASTROCEMETA  (Duj.)  (XXYI.  18).— Body  oval,  convex  on  one 
side,  and  hollowed  by  a  longitudinal  furrow  on  the  other ;  cilia  seated  in  the 
fmTOW,  chiefly  at  the  two  ends. 

Gastrochjeta  Jissa  (xxvi.  18).  —  Semitransparent,  oval,  truncate  in  fi-ont. 
1-408".     In  the  water  of  the  Seine. 

Genus  ALYSCUM  (Duj.)  (XXYI.  20).  — Body  ovoid-oblong  irregular, 
surrounded  by  radiating  cilia,  and  having,  besides,  a  lateral  bundle  of  long- 
retractile  cilia,  by  means  of  which  it  leaps  briskly  from  place  to  place. 

The  single  species  much  resembles  Enchelys  nodulosa  {Paramecium  Milium, 
or  Pantotriclimn  Enchelys,  Ehr.)  from  which  it  is  distinguished  by  its  retractile 
filaments. 


Alyscuini  saltans  (xx^t:.  20). — Colour- 
less, oblong,  rounded  at  the  ends,  rather 
concave  along  the  side  bearing  the  re- 
tractile filaments,  and  marked  by  some 


almost  in\-isible 
1-1300"  to  1130" 
the  Seine. 


longitudinal    fiuTows. 
In  infusions  and  in 


Genus  UROXEMA  (Duj.)  (XXYI.  25).— Body  long,  narrower  in  front, 
rather  curved;  surrounded  by  radiating  cilia,  and  bearing  a  long  straight 
cilium  behind. 


Uronema  marina  (xxvi.  25). — Co- 
lomless,  semi-ti'ansparent,  nodular,  elon- 
gated; contracted  in  front;  slightly 
curved,  with  from  four  to  five  slightly- 
marked  longitudinal  striae.  1-595".  In 
the  MediteiTanean. 


Stein  considers  this  fomi,  as  in  the 
instance  of  Cyclidium  Gkmcoma,  to  be 
merely  an  embryo  of  an  Infusoriimi,  and 
not  an  independent  species. 


616 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


FAMILY  VI.— COLEPINA. 
(XXIV.  284,  285). 

Loricated  animalcules  having  the  mouth  and  anus  placed  at  the  opposite 
extremities  of  the  body.  The  lorica  is  of  the  form  of  a  small  cask,  composed 
either  of  minute  plates  placed  in  a  row,  or  of  little  rings  between  which 
cilia  are  situated ;  anteriorly  it  is  truncated,  smooth  or  toothed,  and  poste- 
riorly terminated  by  three  to  five  little  points  ;  mouth  cihated.  The  diges- 
tive vacuoles  in  these  creatiu^es  are  readily  filled  with  coloured  food,  which  is 
ejected  posteriorly.  Complete  transverse  self-division  has  been  observed. 
A  distinguishing  character  of  the  Ciliated  Protozoa  is  their  asymmetrical 
figui^e ;  but  the  genus  Coleps  is  an  exception  to  the  general  rule. 

In  the  act  of  fission  a  new  formation  of  tissue  appears  to  take  place  along 
the  future  line  of  separation,  thinner  and  softer  in  consistence  than  the 
original  covering. 


Genus  COLEPS  (XXIV.  284-286).— This  being  the  only  genus,  its  cha- 
racteristics are  identical  with  those  of  its  family. 


CoLEPS  Iw'tus  {Cercaria  hirta,  M.) 
(xxiv.  284-286).— Body  white,  oval,  with 
truncated  ends;  lorica  apparently  com- 
posed of  small  polygonal  plates,  between 
which  the  cilia  are  both  transversely 
and  longitudinally  aiTanged.  Anteriorly 
there  are  nineteen  pointed  processes,  and 
posteriorly  three.  Movements  very  brisk ; 
so  that  it  is  difficult  to  examine  the  lorica 
while  the  animal  is  living ;  but  when  it 
is  dried,  or  pressed  between  glasses,  the 
complex  structure  of  the  former  is 
rendered  visible.  Amongst  Confervse. 
1-570"  to  1-430." 

Although  described  by  Ehrenberg  as 
colomiess  or  white,  this  is  no  specific 
character ;  for  it  may  frequently  be  co- 
loured green  by  chlorophyll,  or  tinted 
with  intermediate  shades  between  yel- 
low, green,  and  brown,  according  to  the 
food  taken  and  its  changes  by  digestion. 

C.  viridis. — Green,  oval,  and  ciliated; 
lorica  terminating  in  three  points. 
Amongst  Confervc^.     1-960"  to  1-570". 

Except  in  the  matter  of  colour,  no 
distinction  from  the  preceding  is  noted  ; 
its  specific  independence  may  therefore 
be  fairly  questioned. 


C.  elongatus. — Cylindrical,  elongated; 
lorica  white,  and  terminating  in  three 
points ;  self-division  transverse.  1-570" 
to  1-430". 

Between  this  form  and  C.  hirtus  Perty 
has  seen  every  intermediate  figure,  and 
therefore  regards  it  as  a  mere  variety, 
and  not  a  species.  The  colom',  it  hardly 
needs  be  stated,  is  in  no  way  character- 
istic. 

C.  amphacanthus. — Ovate,  shorter.  Lo- 
rica, unlike  that  of  the  other  species,  com- 
posed of  rings ;  the  anterior  part  crowned 
with  unequal  teeth,  the  posterior  having 
three  strong  spines.  Found  in  Spiro- 
stomum  vij'ens,     1-280". 

C.  incurvus. — Oblong,  nearly  cylin- 
drical, and  slightly  curved;  lorica  ter- 
minating in  five  points.  Amongst  Con- 
ferv£e.     1-430". 

C.  inermis  (Perty). — Lorica  costate, 
not  granular ;  no  spinous  points  at  pos- 
terior end,  or  very  feeble  ones.  Greeu 
corpuscles  occur  internally.  The  dis- 
tinctness of  the  ribs  varies,  as  weU  as  the 
length  and  thickness  of  the  body.  Mo- 
tions like  those  of  C.  hirtus.  1-600". 
Fresh  water. 


FAMILY  VII.— TRACHELINA. 

(XXIV.,  XXVIII.,  XXIX.) 

This  extensive  family  includes  those  animalcules  which  have  two  distinct 
alimentary  orifices — the  recei\ing  one  lateral,  the  discharging  one  terminal. 
They  have  no  lorica  ;  but  all  the  genera,  except  Phialina,  are  covered  with 
vibrating  ciha,  generally  disposed  in  longitudinal  rows,  those  near  the 
mouth  being  the  longest.  Trachdius  has  no  neck ;  but  the  frontal  portion  of 
the  body  is  prolonged,  in  the  form  of  a  long  trunk-like  hp ;  in  Lo.vodes  ^n^ 
ChUodon  it  is  like  a  hatchet-shaped  broad  lip.     In  Glaucoma  there  is  a 


OF  THE  TRACHELINA.  617 

tremulous  flap  to  the  mouth,  and  in  Chilodon  and  Nassula  a  cylinder  of  rod- 
like teeth,  which  sometimes  projects  in  advance  of  the  mouth.  Bursaria  and 
Rassida  have  a  thick  frontal  protuberance.  The  reception  and  discharge  of 
coloured  matter  can  be  seen  in  all  the  genera.  In  Nassula  the  violet- coloured 
specks  (bUe)  are  worthy  of  notice.  In  Spirostomum  the  mouth  is  spiral.  A 
nucleus  and  one  or  more  contractile  vesicles  occur  in  all  the  genera.  Com- 
plete transverse  and  longitudinal  self-division  is  frequent  and  complete. 

The  genera  are  disposed  as  follows : — 

(  (  ^'Oi  f   '^^th  a     nip  long,  proboscis-Uke Trachelius. 


Brow    con- 
No    tremu-         tinuoua 
lous  J      with    the"* 

,      mouth-      I       body. 


brow-hke  \ 
■53  \  upper  Up  [  Hp  broad,  hatchet-shaped. .  .Loxodes. 

o   1,  brow-hke  prominent  back  Bursaria. 


i^  Mouth  spiral    Spirostomi 

^  Brow  interrupted  in  a  peg-like  manner Phialina. 

\^  Mouth  having  a  tremulous  flap Glaucoma. 

A  brow-like  prominent  upper  lip  Cliilodon. 

A  brow-like  prominent  back  Nassida. 


This  family  is  not  recognized  by  Dujardin,  who  rejects  the  supposed  affini- 
ties of  its  genera  as  imnatural ;  and  indeed  it  must  be  owned  that  the  Tra- 
chelina,  as  understood  by  Ehrenberg,  represent  a  heterogeneous  collection 
rather  than  a  natural  group.  Bursaria  includes  some  mouthless  Opalinm. 
Spirostomum  evidently  takes  its  place  next  to  Stentor ;  and  Chilodon  and 
Nassida  are  removed  in  several  important  details  of  organization  fi'om  Tra- 
chelius and  Phialina. 

Perty  retains  in  his  classification  a  family  Trachelina,  and  places  in  it  the 
genera  Trachelius,  Harmed irus,Amphileptus,  Loxophyllum,  Dileptus,  Pelecida, 
and  Loxodes, — adopting,  however,  the  characters  assigned  by  Dujardin  in 
preference  to  those  given  by  Ehrenberg.  The  brief  character  of  Trachelina 
recorded  is — "  Body  elongated  anteriorly  into  a  neck-like  process,  or  pro- 
truding a  proboscis  curved  on  one  side." 

We  have  retained  in  the  preceding  description  of  Trachelina,  adopted  fi'om 
Ehrenberg,  several  notes  of  stnictm-al  peculiarities  which  subsequent  re- 
searches show  to  be  erroneous.  That  the  mouth  is  lateral  and  the  anus  ter- 
minal in  all  the  members  of  the  family  is  not  the  case.  Thus,  in  Chilodon  the 
discharging  orifice  is  on  one  side,  near  the  posterior  extremity.  Lachmann 
{A.  N.  H.  1857,  xix.  p.  216)  speaks  of  the  buccal  orifice  of  Glaucoma  as 
produced  into  two  fiaps.  The  teeth  (so  called)  in  Nassula,  Chilodon,  kc, 
have  no  real  claim  to  that  designation  ;  for  they  are  no  more  than  folds  or 
thickenings  of  the  oesophagus  (see  Part  I.  p.  311).  The  violet- colom-ed  spots, 
imagined  by  Ehrenberg  to  be  vesicles,  are  merely  accidental  specks  of  colour 
derived  from  the  food  (see  p.  312,  and  notes  on  Nassula  elegans). 

Chilodon  and  Nassula  have  been  proved  to  propagate  by  living  embiyos, 
after  a  previous  encysting-stage ;  and  in  all  probability  most  of  the  other 
genera  do  so  likew^ise.  Nassula  ambigua  (Stein)  has  been  seen  in  the  same 
encysted  condition  as  Chilodon ;  and  only  the  last  stage,  that  of  the  internal 
development  of  a  ciliated  embryo,  to  complete  the  cycle  as  in  Chilodon,  has 
escaped  observation. 


618 


SYSTEMATIC  HlSTOEY  OF  THE  INFTJSOEIA. 


Genus  TRACHELIUS  (XXIV.  287-290).— Body  ciliated ;  mouth  simple, 
destitute  of  teeth,  is  seated  on  one  side  at  the  base  of  the  very  much  elon- 
gated upper  lip  or  proboscis.  Cilia  are  absent  in  three  species.  In  four 
species  coloured  food  has  been  received,  and  in  three  the  discharging  orifice 
detected.  It  has  also  a  coUapsed  oesophagus,  visible  only  during  the  passage 
of  food.     Two  species  increase  by  transverse  self- division. 

This  genus  forms  a  member  of  the  family  "  Trichodiens "  (Trichodina) 
(Duj.),  along  with  Trichoda  and  genera  named  Acineria,  Pelecida,  and 
I)ile2:)tus. 

The  account  he  gives  of  the  animals  differs  much  from  the  foregoing.  Ac- 
cording to  it,  Trachelius  is  destitute  of  a  contractile  or  reticulated  integu- 
ment, and  is  composed  of  a  muco-gelatinous  substance  (sarcode)  containing 
granules,  which  are  oftentimes  agglomerated  in  the  form  of  nodules,  disposed 
in  rows.  The  apparent  oviposition  in  T.  Ovum  and  T.  Meleagris  was  nothing 
more  than  the  breaking  up  of  part  of  the  animalcule  by  "  diffluence,"  and 
the  supposed  ova  only  particles  of  ''  sarcode." 

"  The  cilia  at  the  anterior  extremity  are  larger  than  those  on  the  rest 
of  the  body.  Posteriorly  a  large  vacuole  is  often  to  be  seen.  There  is  no 
distinct  mouth." 

The  last  statement  is  contradicted  by  recent  investigations,  which  prove 
that  the  animalcules  belonging  to  this  family  have  a  mouth,  and  some  of 
them,  at  least,  an  anus. 


Trachelius  Anas  {Trichoda  Anas  et 
Index,  M.)(xxiv.  287-289).— White, cla- 
vate,  and  cylindrical;  proboscis  thick, 
obtuse,  not  half  the  length  of  body; 
mouth  situated  close  to  the  base  of  the 
proboscis.  In  exposed  infusions,  and 
fi-eshwater  swamps,  amongst  Confei-vse. 
The  interior  often  contains  green  (chlo- 
rophyll) vesicles.     1-280"  to  1-120". 

T.  vorax. — Clavate-ovate,  turgid,  co- 


lour 


proboscis    thick,    obtuse, 


shorter  than  half  the  body ;  mouth  situ- 
ated near  the  middle  of  the  body,  and 
not  at  the  base  of  the  proboscis.  Amongst 
Confervc^.     1-120". 

T.  Meleagris. — Compressed,  lanceolate, 
often  curved  in  the  form  of  the  letter  S ; 
proboscis  thick,  obtuse,  shorter  than  half 
the  body.     1-96"  to  1-60". 

Ehrenberg  described  in  this  species  a 
red-coloured  fluid  which  he  called  bile, 
and  a  row  of  ten  to  twelve  vesicles  along 
the  back,  which  he  concluded  to  be  sto- 
mach-cells filled  with  red  gastric  juice.  It 
is  now,  however,  admitted  that  these  cells 
are  really  contractile,  and  fonn  a  vascular 
chain.  The  nucleus  is  oval,  with  a  cen- 
tral constriction.  Dujardin  adopted  this 
species  as  one  form  of  a  new  genus, 
Loxophyllmn,  hereafter  described  in  the 
family  Colpodea. 

T.  Lamella  (Kolpoda  Lamella,  M.) 
(xx^^.  24  a,  b).  —  Depressed,  laminar, 
elongated,  linear-lanceolate,  often  trim- 
cated  anteriorly  and  rounded ;  margin 
ciliated  (Dujardin  says,  only  in  front). 


Ehrenberg  considers  this  form  may  be  no 
other  than  the  young  condition  of  A}n- 
philejjtus  Fasciola ;  and  Perty  woidd  add, 
of  Spathidimn  hyalijium.  In  sea-water. 
1-900"  to  1-200". 

T.  Anaticula.  —  White,  small,  ovate, 
pyiiform,  attenuated  and  diaphanous  an- 
teriorly. Dujardin  believes  he  has  seen 
several  of  these  animalcules  become  by 
simple  contact  agglutinated  together, — 
a  circumstance  which  woidd  indicate  the 
absence  of  a  true  integument.  Amongst 
Conferv£e.     1-570"  to  1-280". 

T.  (?)  tricJiopJiorus  (  Vibrio  strictus,  M.) 
— Cylindrical,  changeable,  often  clavate; 
proboscis  capitate,  of  the  form  of  a  very 
delicate  whip.     1-1200"  to  1-430". 

T.  (?)  glohdifer.  —  Spherical,  hyaline, 
with  a  very  delicate  whip-like  acute  pro- 
boscis.    Ajnongst  Confervas.     1-200". 

T.  Ovum  (xxiv.  290). — Large,  ovate, 
wide  or  campanidate  anteriorly;  pto- 
boscis  short,  in  the  form  of  a  beak ;  con- 
tractile vesicles  numerous.  "  In  no  in- 
fusorial animalcule,"  says  Ehrenberg,  "  is 
the  alimentary  canal  so  easily  seen  as  in 
this ;  the  large  mouth  and  contractile 
vesicle,  Ijang  over  the  lower  part  of  the 
alimentary  canal,  are  equally  evident; 
nmnerous  smaU  digestive  cells  and  ova- 
granules  appear  in  every  part. "  It  is  in 
this  species  that  LieberkUhn  and  Lach- 
mann  have  latterly  described  the  exist- 
ence of  an  arborescent,  ramified  digestive 
canal,  quite  distinct  from  the  cl^ar  round 
spaces  in  the  parenchyma  of  the  body, 


OF  THE  TRACHELIN'A. 


619 


which  some  have  supposed  to  be  sto- 
machs. In  stagnant  bog-water.  1-72." 
It  has  been  foimd  encysted.  (Vide  Part  I. 
p.  309). 

T.  (?)  laticeps. — Flattened,  elliptical ; 
anterior  part  (head)  membranous,  vari- 
able and  wide,  with  a  notch  from  which 
proceeds  a  flagelliforni  proboscis  almost 
double  the  length  of  the  body.  1-912". 
In  North  Sea. 

T.  demlrophihis.  —  Ovate,  subacute  at 
each  end ;  proboscis  verv  fine,  acute, 
double  the  length  of  the  bodv.  1-288'"  ; 
with  filament,  1-96'"  to  1-72'".  Has  the 
habit  of  a  Monad,  but  the  motion  of  T. 
trichopliorus,  than  which  it  is  very  much 
smaller.     On  ti-ee-mosses. 

T.  str ictus  (Duj.). — Filiform,  extremi- 
ties rather  pointed ;  the  cilia  visible 
only  in  front.  1-400".  Amongst  Lemnse  j 
seen  also  by  Perty  in  Switzerland. 

T.  teres. — Filiform,  cylindrical,  obtuse 
anteriorly,  pointed  and  tapering  behind ; 
ciliated  only  in  the  anterior  margin. 
1-170".     In  stagnant  sea- water. 

T.  Falx. — Long,  depressed,  lanceolate 


or  sigmoid ;  variable ;  narrower  and 
rather  curved  anteriorly  in  a  sickle-like 
form;  ciliated  generally.  1-420".  In 
pond-water. 

T.  noduliferus  (Perty). — Very  slender, 
narrowed  anteriorly,  but  terminated 
abruptly  by  a  rounded  end;  colom-less, 
but  with  diffused  chlorophyll-vesicles  at 
times,  and  granules.  Cilia  scarcely  vi- 
sible, except  near  the  head,  where  they 
are  rather  larger.  Movements  slow.  The 
elongated  neck-like  portion  devoid  of 
molecules.     1-570"  to  1-120"  (Bern). 

T.  apicidatus.  —  Slender,  tapering  an- 
teriorly, its  end  being  obtuse.  Colom*- 
less,  with  diffused  vesicles  and  molecules. 
Cilia  very  delicate.  Movements  rapid, 
like  those  of  Trachelocerca.     1-144". 

T.  pusiUus. — Considerably  elongated ; 
rather  flattened;  colomiess;  with  a  round 
opening  at  its  naiTower  anterior  ex- 
tremity. Movements  tolerably  quick, 
with  slow  revolutions  on  its  axis. 

Perty  intimates  it  to  be  the  same 
species  as  Trachelius  trichophorus  (Ehr.) 
and  the  Peranema protractum  (Duj.). 


Genus  LOXODES  (XXIV.  291-293).— Body  ciHated  throughout,  mouth 
simple,  devoid  of  teeth ;  upper  lip  continuous  and  broad,  hatchet-shaped ; 
locomotive  cilia  longer  near  the  mouth.  The  contractile  vesicle  is  round ; 
the  nucleus  oval  or  ovoid.  In  L.  Bursaria  an  oval  nucleus  and  two  contrac- 
tile globular  vesicles  have  been  seen.     Self- division  transverse. 

Dujardin's  characters  of  Loxodes  are — "  Body  flat,  membranous,  or  with  an 
apparently  membranous  lorica,  flexible  but  not  contractile,  expanded  at  the 
centre  of  its  superior  or  dorsal  siu-face,  often  concave  on  the  under  siuface ; 
contour  irregularly  oval,  sinuous  and  obliquely  prolonged  anteriorly ;  fiimished 
with  very  fijie  cilia,  confined  to  its  anterior  margin.  In  general  characters," 
he  adds,  "  Loxodes  approaches  nearest  to  Trachelius  (family  Trichodina)  ;  but 
the  signs  of  an  integument  are  so  clear  as  to  sever  it  from  that  genus  and 
family."  The  Loxodes  described  by  the  French  author  are  almost  all  of  them 
distributed  by  Ehrenberg  among  other  genera  and  families ;  and  hence  there 
is  unfortimately  none  but  the  slightest  relation  between  the  similarly-named 
genus  of  the  two  writers.  Thus  the  Loxodes  JRostrum  of  Ehrenberg  is  the 
representative  of  a  genus  Pelecida,  of  the  family  Trichodina,  in  the  system  of 
Dujardin,  and  bears  the  name  of  Pelecida  Rostrum.  In  this  position  it  is 
brought  into  close  relation  with  the  genera  Triclioda  and  Tixichelius  (Ehr.), 
and  with  two  others,  named  by  Dujardin  Aciduria  and  Dileptus. 

The  last-mentioned  genus  comprises  Infusoria  placed  by  Ehrenberg  with 
Ampliilep)tus,  in  describing  which  we  shall  take  the  opportunity  to  give  the 
characters  of  Dileptus,  whilst  Acineria  and  Pelecida  will  be  included  among 
the  appended  genera  at  the  end  of  the  present  family,  Trachelina. 


Loxodes  Rostrum  {Kolpoda  Rostnmi, 
M.,  Pelecida  Rostrum,  D.)  (xxiv.  291- 
293). — Body  compressed,  white,  lanceo- 
late, slightly  curv^ed  in  the  form  of  an  S, 
in  consequence  of  the  lip  being  a  little 
uncinated.    Ehrenberg  states  that  he  has 


very  often  seen  large  Navicidce  and  Syn- 
edrcB  within  this  creature,  although  it 
would  not  feed  on  colom'ed  food.  The 
cilia  are  very  delicate,  (xxiv.  291,  an 
animalcule  which  has  fed  upon  Bacil- 
laria  ;  xxiv.  292,  another,  creeping  along 


620 


SYSTEMATIC  HISTOET  OF  THE  INFUSORIA. 


Confervie  ;  and  xxv.  293,  a  specimen 
iindergoing  transverse  self-division.) 
Amongst  Conferv^ae.     1-144"  to  1-36". 

L.  Cithara  (Trichoda  aurantia,  M.). — 
Triangular  and  compressed ;  anteriorly 
dilated  and  obliquely  truncated,  but 
pointed  at  the  posterior  extremity.  Co- 
lour white.     1-430"  to  1-210". 

L.  Bursar ia.  — Oblong ;  anteriorly  ob- 
liquely truncated  and  depressed ;  poste- 
riorly hemispherical.  The  mouth  is  placed 
near  the  centre  of  the  ventral  surface,  at 
the  bottom  of  a  deep  funnel-like  fossa 
(vestibulum),  the  upper  border  of  which 
is  longer,  broader,  rather  concave,  and 
truncate,  and  constitutes  the  "upper 
lip"  of  Ehrenberg.  A  long  oesophagus 
extends  far  into  the  interior  from  the 
mouth.     In  bogs.     1-280". 

This,  Focke  and  Stein  show,  is  not  a 
species  of  Loxodes,  but  of  Paramecium, 
and  therefore  rightly  named  P.  Bursaria 
(which  see,  p.  635).  It  was  this  species 
which  was  so  elaborately  examined  by 
Cohn,  especially  with  regard  to  its  repro- 
duction. Young  specimens  are  colourless; 
but  matiu'e  beings  have  nimierous  chlo- 
rophyll-corpuscles diffused  in  their  cor- 
tical laminae .  There  are  two  round  con- 
tractile spaces,  which  by  pressm-e  assume 
a  stellate  appearance  similar  to  those  of 
P.  Aurelia.  The  rotation  of  the  contents 
may  be  demonstrated  in  this  species ;  and 
Cohn,  Focke,  and  Stein  have  witnessed 
its  reproduction  by  a  living  germ  or  em- 
bryo. In  figure  it  is  very  like  Chilodon 
Cucidlulus,  but  has  the  oral  fossa  (vesti- 
bule) and  cilia  of  Paramecium, 


L.  plicattis.  —  Elliptical,  depressed, 
convex  on  the  back,  and  slightly  plicated; 
the  lip  uncinate.    On  Confervse.    1-430". 

The  species  of  Loxodes  mentioned  by 
Dujardin  are  L.  Cucullidus  =  Chilodon 
Cucullus  (Ehr.) ;  and  L.  Cucullio  =  (?) 
Kolpoda  Cucullio  (M.),  placed  by  Ehren- 
berg among  the  Kolpodea. 

L.  reticulatus.  —  Oval ;  more  slender, 
sinuous,  and  flexible  anteriorly ;  surface 
granular.     In  long-kept  marsh-water. 

This  species  is,  in  Stein's  opinion,  a 
mere  accidental  variety  of  ChilodonCucul- 
lulus,  determined  by  the  bulk  of  food 
received. 

L.  marinus. — Depressed,  oval,  almost 
renifoim;  with  internal  tine  granules, 
and  a  row  of  puncta  near  both  the  ante- 
rior and  posterior  margins.  1-350".  In 
salt  water. 

L.  dentatus. — Similar  to  L.  Cucullulus, 
but  ha\'ing  a  bundle  of  bristles  about  the 
mouth,  as  in  Giilodon,  from  which  it 
differs  by  the  lorica  (cuirass)  and  by  the 
absence  of  cilia  on  the  surface. 

The  distinction  of  this  species  and  L. 
Cucullulus  as  independent,  Stein  rightly 
criticizes  as  an  error  on  the  part  of  Du- 
jardin, and  shows  {Infus.  p.  131)  that  both 
of  them  are  only  accidental  varieties  of 
Chilodon  Cucullulus, — Loxodes  Cucullulus 
being  nothing  more  than  small  specimens 
in  which  the  oesophagus  is  indistict,  and 
L.  detitatus  examples  in  which  this  organ 
is  very  evident. 

L.  hrevis  (Perty).  —  Short,  rounded, 
with  a  hyaline  proboscis.  1-500".  Bern, 
in  rainwater-ponds. 


Genus  BURSARIA  (XXIV.  294-296).— Surface  ciHated  throughout;  an- 
terior part  convex ;  mouth  not  terminal,  fringed  with  stronger  cilia,  though 
simple,  toothless,  and  devoid  of  tremulous  flap.  The  cilia  are  distinctly  seen 
in  coloured  water,  and  are  generally  disposed  in  rows;  those  around  the 
mouth  are  longer  than  the  others.  The  nutritive  system  (says  Ehrenberg) 
consists  of  an  alimentary  canal,  cui'ved  forwards ;  it  is  fui'iiished  with  diges- 
tive cells  resembling  little  purses,  which  are  attached  to  it  by  short  stalks. 
The  mouth  is  large,  situated,  as  in  Leucophrys,  obliquely  at  the  anterior  ex- 
tremity, so  that  a  brow,  as  it  were,  either  projects  over  it  or  else  forms  the 
end.  The  contractile  vesicle  is  sometimes  doubled ;  the  nucleus  oval  or 
ovoid.  The  anus  is  placed  at  the  posterior  extremity.  SeLf-di\dsion,  longi- 
tudinal or  transverse,  has  been  observed  in  five  species. 

Dujardin  has  the  following  remarks  on  this  genus : — "  Ehrenberg,  whilst 
admitting  a  genus  Bursaria,  separates  from  it  several  true  species,  and 
places  some  of  them  in  his  genus  Leucophrys,  others  in  his  family  Kolpodea ; 
whilst  the  closely  allied  genera  Kondylostoma  and  Playiotoma  are  confounded 
with  other  families — the  former  with  O.vytriclia,  the  latter  with  Paramecium. 
Moreover,  the  obliquity  of  the  mouth  in  Bursaria  is  not  a  sufficient  distinc- 
tion between  that  genus  and  Leucophrys  ;  and,  whilst  assigning  a  large  mouth 


OF  THE  TRACHELINA. 


621 


to  the  Bursarke,  he  inchides  among  them  several  species  in  whieh  the 
existence  of  a  mouth  is,  to  say  the  least,  doubtful." 

The  genus  Bursaria  is  taken  as  the  representative  of  a  distinct  family,  both 
by  Dujardin  and  by  Perty.  The  former,  who  names  it  "  Bursaiina,"  insti- 
tutes five  genera,  viz.  Plagiotoma,  Ophryoglena,  Bursaria,  Spirostomum,  and 
Condylostoma.  The  latter  adopts  the  same  name,  and  ranges  the  family  in 
his  section  Monima,  comprehending  Ciliata  which,  although  very  contrac- 
tile, and  clothed  by  a  soft  integument,  always  retain  their  form.  The  genera 
included  among  the  Bursarina  by  Perty  are  Lembadion  and  Bursaria, — ^the 
former  a  new  genus  established  by  himself  to  receive  two  species  which  he 
does  not  find  indicated  by  Ehrenberg.  Dujardin  defines  the  Bursarina  as 
"  animals  possessing  a  highly  contractile  body,  very  variable  in  fonn,  mostly 
oval,  ovoid,  or  oblong ;  ciliated  throughout,  and  having  a  large  mouth  sur- 
mounted by  a  band  or  surrounded  by  a  spirally  curved  row  of  cilia." 

The  genus  Bursaria  is  closely  allied  to  Paramecium,  from  which  it  is 
chiefly  distinguished  by  the  row  of  larger,  longer  cilia  about  the  mouth,  ex- 
tending along  the  deep  fossa  in  which  that  orifice  is  contained.  In  Para- 
mecium the  cilia  are  everywhere  of  the  same  size. 

Several  of  the  Bursarice  enumerated  by  Ehrenberg  have  been  shown  to  be 
Opalines,  and  to  be  destitute  of  a  mouth.  These  species  are  B.  Ranarum, 
B.  Entozoon,  B.  intestincdis,  and  B.  Nucleus,  all  which  are  further  remarkable 
in  being  parasitic  in  Batrachia.  The  B.  cordiformis  is  also  a  parasite  of  the 
intestine  of  the  frog,  and,  although  a  doubtful  member  of  the  genus,  has  the 
sanction  of  Stein  to  the  generic  position  accorded  it. 


a.  Sub-genus  Buesaria. 


Burs ahi A  truncatella  (M. ) .  The  trun- 
cated Bursaria. — Large,  visible  to  the 
naked  eye ;  white,  ovate,  tm'gid,  trun- 
cated and  broadly  excavated  in  front, 
where  there  is  a  simple  row  of  cilia.  In 
some  specimens,  Ehrenberg  saw  half-di- 
gested Rotifera  and  large  quantities  of 
vegetable  matter  in  the  nutritive  cells, 
and  was  able,  as  he  thought,  by  means  of 
carmine  given  as  food,  to  trace  an  ali- 
mentary canal  through  the  greater  part 
of  its  com-se.  In  each  vacuole  the  food 
appears  surrounded  by  a  clear  fluid,  which 
Ehrenberg  calls  bile.  A  large  bright 
vesicle  is  seen  below  the  mouth  and 
somewhat  to  the  left  of  it,  on  which  side 
is  also  a  large  curved  but  not  articulated 
nucleus,  reaching  to  the  brow  or  frontal 
region.  In  ditches  and  ponds,  amongst 
rotten  beech-leaves.     1-48"  to  1-36". 

B.  Vorticella  (xxiv.  294). —White  .; 
large,  nearly  spherical,  and  turgid ;  an- 
teriorly tnmcated  and  widely  excavated, 
with  a  double  row  of  cilia.  Found  with 
Chlamydomo7uis  Pulvisculus  and  Gonium 
pectorals,  which  are  sometimes  seen 
within  it,  as  in  xxiv.  294.     1-108". 

B.  vorax. — Large,  oblong,  rounded  at 
the  ends ;  mouth  ample,  being  one -third 
the  length  of  the  body,  and  touching  the 
summit  of  the  frontaf  region.     This  spe- 


The  inferior  (not  anterior)  Up  reaching  to  the 
frontal  margin. 

cies  has  great  resemblance  to  Urostyla 
grandis  and  Stylonychia  lanceolata,  when 
their  claws  and  styles  are  withdrawn. 
In  muddy  water  in  summer.  1-140"  to 
1-108". 

B.  (Opalina)  Entozoon. — Large,  cylin- 
drical, tiu-gid,  nearly  equally  rounded  at 
both  extremities;  mouth  small,  near  the 
frontal  apex.  Found,  with  the  following, 
in  the  rectum  of  Rana  temporaria  (the 
Frog),  in  summer  and  winter. 

Perty  represents  this  as  a  mere  variety 
of  B.  Ranarum.  He  also  treats  B.  Nucleus 
and  probably  B.  itdestinaUs  as  other  va- 
rieties of  the  same  being,  and  therefore 
Opalines. 

B.  (  Opalina  ?)  intestinalis  (  Vibrio  Ver- 
miculus,  M.). — Slender,  cylindrical,  at- 
tenuated posteriorly ;  mouth  small,  situ- 
ated below  the  frontal  apex.  In  this 
species,  as  well  as  in  others,  Ehrenberg 
has  seen  transverse  self-di\-ision.  Found 
with  the  preceding.  1-240"  to  1-120". 
It  is  probably  an  Opalina. 

B.  (?)  cordiformis. — Reniform,  front 
depressed,  mouth  slightly  curved  in  a 
spn-al  manner ;  colom' white.     1-210". 

This  species  Stein  afiirms  to  be  a  trut? 
Bursaria ;  but  Perty  makes  it  an  Opa- 
lina,— a  view  countenanced  by  its  para- 
sitic nature. 


622 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


B.  lateritia  (T?'ichoda  ignita,  M.). —    colour.     With  Lemnae,   ConfeiTse,  &c. 
Compressed,  ovato-triangular,  with  the     1-430"  to  1-144". 
front    sharply   crested,  of   a    brick-red 

b.  Frontonia. — Anterior  'part  of  the  body  (hroiu)  irrojeds  beyond  the  mouth, 

and  is  convex. 


B.  vernaUs  (Leucophra  vi7'escens,'M.). — 
Oval,  tiu'gid,  rounded  at  the  ends,  and 
attenuated  posteriorly.  The  mouth  has 
a  wreath  of  stiff,  short  bristles,  resembling- 
teeth  ;  nimierous  digestive  vacuoles  are 
often  fiUed  wdth  large  Oscillatoriae,  Na- 
viculge,  &c.  (and  contain  a  reddish  bile, 
Ehr.).  The  progressive  digestion  of  the 
OsciUatorise  is  interesting  to  follow  : — 
they  are  at  first  elastic  and  rigid,  and  of 
a  beautiful  blue-green  colour,  then  di- 
stinctly lax,  flexible,  and  bright  green, 
becoming  afterw^ards  yellowish  green, 
and  resolved  into  separate  segments, 
which  at  length  turn  yellow.  Amongst 
Oscillatoriae  in  spring.    1-144"  to  1-120". 

B.  leucas  (xxiv.  295  -,  xxx.  1).  —  Ob- 
long, cylindrical;  extremities  nearly  equi- 
convex  (bile  colouiless).  This  creature 
has  a  contractile  bladder,  with  a  cmious 
j  agged  margin  near  the  long  open  mouth. 
With  Oscillatoriae,  and  on  the  surface  of 
water.     1-144". 

B.  Fiqjci  (xxiv.  296).— White,  ovate- 
oblong,  rather  acute  posteriorly  j  mouth 
inferior,  and  near  the  frontal  apex  (see 
f.  296).  1-280".  In  chalybeate  w^ater, 
Germany. 

B.  Jlava. — Ovate-oblong,  often  acute 
at  the  posterior  extremity;  the  mouth 
occurs  in  the  flat  concavity  immediately 
behind  the  round  brow.  In  bog- water. 
1-140"  to  1-96". 

^'  This  species,"  says  Pei'ty,  "  differs 
much,  both  in  its  flgm-e  and  its  narrow^er 
oral  tissm'e,  from  true  BuisaricB,  and 
ranges  better  with  Pa/wphrys.^^  Dujar- 
din,  again,  considers  JB.  jiava,  B.  leucas, 
and  B.  vernalis  to  be  merely  three  va- 
rieties of  his  Panophrys  farcta. 

B.  {Opalina)  Nucleus. — Small,  white, 
ovate,  attenuated  anteriorly;  extremities 
convex.  In  Rana  toiiporaria  and  P.  es- 
culenta,  1-240".  Vide  notes  on  B.  En- 
tozoon. 

B.  (Opalinci)  Ranarum. — Ovate-lenti- 
cular and  compressed,  subacute  ante- 
riorly; the  back  and  belly  carinated ;  often 
tnmcated  posteriorly;  mouth  inferior, 
near  the  frontal  apex.     1-210"  to  1-72". 

The  mouth  here  described  has  been 


diligently  sought  for  by  Stein  and  others; 
but  they  can  find  nothing  more  than  a 
fold  of  the  surface,  with  no  orifice  in  it, 
as  sho^Ti  by  reagents.  This  species  is 
therefore  a  member  of  the  mouthless 
group  Opalinaea  (vide  subclass  Opali- 
n^a,  p.  269,  and  Pis.  xxn.  46, 47 ;  xx^i. 
28,  29). 

B.  (?)  aurantiaca, — Ovate-oblono-,  an- 
teriorly obtuse,  posteriorly  acute ;  it  has 
an  ash-colom-ed  spot  near  the  mouth. 
Amongst  OsciUatoiiae.     1-280". 

B.  arhorum.  —  Oblong,  compressed; 
A'ery  finely  ciliated;  ends  rounded;  mouth 
situated  in  the  anterior  third  of  the  body, 
reaching  its  fi'ontal  extremity;  a  wreath 
of  larger  cilia  extending  around  and 
backw-ards  from  the  mouth.  Length 
1-40"',  double  the  breadth;  vacuoles 
nimierous,  and  tw^o  globular  nuclei  seen. 
On  moss  of  trees. 

B.  triquetra.  —  Ovate-lenticular ;  very 
finely  ciliated ;  dorsimi  flat;  venter  tm-gid 
and  slightly  keeled,  hence  an  imperfect 
triquetral  figm-e  of  the  animal ;  anterior 
extremity  subtruncate  ;  oral  flssm-e  long, 
extending  from  the  frontal  end,  fi-inged 
with  a  row  of  strong  cilia  extending 
backw^ards;  nuclei  tw^o,  smaU;  vesicle 
large,  contractile,  simple,  near  the  pos- 
terior extremity.  Swims  slow^ly.  1-36"'. 
On  moss  of  trees. 

B.  Blattarum  (Stein). — Is  very  like 
B.  cordiformis,  but  more  compressed; 
roimded  in  front,  where  there  is  a  very 
opaque,  sharply-defined,  coarse-granular, 
and  posterior  to  it  the  transverse  oval 
nucleus.     In  intestine  of  Blatta. 

B,  patula  (Duj.  and  Perty)=ieMCO- 
pkrijs  patula  (Ehr.)  ;  Bursaria  virens 
(Perty)  =  Spirostominn  virens  (Ehr.) ; 
and  Bursaria  spirigera. 

B.  Loxodes  ('Pertj)  =  Loxodes Bursaria 
(Ehr.). — Under  no  circumstances  can 
this  species  (says Perty)  be  reckoned  with 
Loxodes  (Ehr.),  or  wath  Pelecida  (Duj.). 

B.  Ztimh'ici (Stein)  =  Plagiotoma Lum- 
hrici  (Duj.)  =  Paramecium  compressum 
(Ehr.)  is  a  Bursaria,  not  a  Parame- 
cium, having  a  row  of  longer  cilia  about 
the  mouth  and  ventral  sm-face. 


Genus  SPIROSTOMUM  (XXIV.  296*-298).— Body  elongated,  or  ribbon- 
shaped,  flexible  and  ciliated,  the  frontal  region  continnous ;  mouth  lateral, 
spiral-shaped,  devoid  of  teeth,  but  with  a  tremulous  flap.     The  locomotive 


OF  THE  TRACBLELIN'A. 


623 


cilia  are  disposed  in  rows ;  those  at  the  mouth  are  longer,  and  form,  as  in 
Stentor,  a  spii^al  Avreath  around  it ;  in  >S^.  amhiguum  the  brow  and  wreath  are 
remarkably  long.  Vacuoles,  to  the  number  of  ninety,  have  been  seen  filled 
with  coloured  food,  and  the  discharge  of  the  latter  observed.  The  anus  is 
placed  at  the  posterior  extremity.  [A  band-like  thick  gland  (nucleus)  is  seen  in 
S.  virens,  and  a  bead-like  one  in  other  species.]  The  former  likewise  possesses 
a  large  contractile  vesicle,  and  green  granules  ;  in  S.  amhiguum  the  granules 
are  white.  Self-division  has  not  been  observed,  but  Ehrenberg  presumes  that 
it  takes  place  transversely. 

The  band-like  or  moniliform  gland  mentioned  by  Ehrenberg  is  in  fact  a 
pulsating  vessel  extending  almost  the  entire  length  of  the  animalcule.  The 
genus  does  not  belong  to  Trachelina,  but  to  a  family  represented  by  Stentor y 
which  Lachmann  and  others  would  establish  with  the  name  of  Stentorina. 
Perty  transfers  Sj)irostomum  to  Urceolarina,  in  which  family  it  is  imited  with 
Stentor,  CcenomorpTm,  and  Urocentrum.  (See  remarks  on  Yoeticellina, 
p.  579.) 


Spirostomum  virens  (^Bursaria  spiri- 
gera,  D.)  (xxrv.  296*). — Ovate-elongate, 
depressed  ;  truncated  anterior!}^,  and 
rounded  posteriorly.  The  back  is  arched, 
and  the  imder  side  flat.  The  green  gra- 
nules are  sometimes  absent  (f.  296*). 
1-120"  j  ova  1-6000". 

S.  amhiquum  {Leucoplirys  \Tricliodc{\ 
ambigua,  M.)  (xxiv.  297,  298.)— "WTiite, 
cyHndrical,  filiform,  flexible  ;  obtuse  an- 
teriorly, trmicated  posteriorly ;  an  elon- 
gated frontal  region  or  brow  extends  be- 
yond the  mouth.  The  long  vibrating 
cilia  in  front  often  appear  like  a  pro- 
boscis, and  were  mistaken  for  such  by 
Miiller.  The  structure  of  this  creature 
is  remarkable,  especially  the  mouth, 
which  is  only  one-fifth  from  the  tail ; 
thus  the  frontal  region  or  brow  is  very 
long,  and  the  alimentary  canal  (adds 
Ehr.),  first  inflected  forwards,   returns 


along  the  body.  From  the  mouth  to  the 
anterior  or  top  of  the  brow  runs  a  long 
ciliated  fm-row  (xxiv.  297  and  298).  In 
swdmniing,  they  extend  themselves,  and 
are  readily  perceived  by  the  naked  eye. 
In  ditches,  among  decaying  oak-leaves 
and  rotten  wood.     1-12". 

Both  Dujardin  and  Perty  consider  this 
animalcide  to  be  the  same  as  that  other- 
wise described  by  Ehrenberg  as  Uro- 
lejjtus  Filum. 

S.  sempervirescens  (Perty).  —  Body 
round,  fiUed  "^dth  green  granides ;  tail 
broad,  flat,  and  colomless.  CiHa  at 
anterior  extremity,  clearly  seen.  The 
gTeen  colour  was  probably  due  to  the 
food.  1-96".  Among  Lemnae,  but  only 
once.  'It  is  allied  to  Kondylostoma 
(Duj.),  which  differs  from  it  by  its 
marine  habitat. 


Genus  PHIALIXA  (XXIV.  299).— The  frontal  ciliated  portion  is  sepa- 
rated from  the  non- ciliated  body  by  a  constriction  or  neck ;  mouth  lateral, 
devoid  of  teeth.  The  motion  of  these  creatures  is  due  to  the  powerful 
wreath  of  cilia  over  the  mouth.  Ehrenberg  says,  cilia  may  possibly  be 
present  upon  the  sm^face  of  the  body,  since  Miiller  described  them  in  Trichoda 
mellitea.  A  contractile  vesicle  (perhaps  two)  is  situated  posteriorly.  Self- 
division  probably  transverse. 

Dujardin  rejects  this  genus ;  and,  in  Perty' s  opinion,  the  animalcules  it 
includes  are  no  other  than  more  contracted  and  ^^ounger  sj^ecimens  of  Tra- 
chelocerca  linguifera  or  of  Lacryynaria.  Amongst  them  are  siDccimens  with 
an  evident  terminal  flap  or  tongue,  and  others  with  incompletely  developed 
necks.     Their  movements  are  rapid.     (See  notes  on  Lacktmaeia,  p.  609.) 

attenuated;    neck  very  short,     1-280". 


Phialina  vermicularis  (TricJioda  ver- 
micalaris,  M.). — Ovate,  attenuated  an- 
teriorly ;  neck  verv  short ;  colour  white. 
With  Lenmfe.     1-240". 

P.  viridis  (xxiv.  299).— Bottled-shaped, 
anterior  part  acute,  the  posterior  gradually 


There  is  nothing  distinctive  in  the 
assigned  characters  of  this  species ;  the 
slight  difference  in  form  may  arise  from 
the  varpng  amount  of  contraction.  The 
green  colom'  is  valueless. 


624 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Genus  GLAUCOMA  (XXIV.  300-302 ;  XXVIII.  4-7).— Body  oval,  com- 
pressed, covered  with  cilia ;  mouth  provided  with  a  tremulous  flap,  but  no 
teeth.  Ehrenberg  described  the  reception  and  discharge  of  food,  and  the 
presence  of  digestive  vacuoles,  and  therefore  saw,  in  these,  indications  of  the 
existence  of  an  alimentary  canal.  The  large  mouth,  with  its  vibratory  valves, 
is  situated  on  the  inferior  side,  in  advance  of  the  middle.  The  anus  is  situated 
on  the  ventral  surface,  near  the  posterior  extremity,  or  at  the  extremity 
itself.  The  internal  organs  are  a  large  ovate  gland,  a  star-like  contractile 
sac,  and  granules.     Self- division  transverse  or  longitudinal. 

Glaucoma  is  comprised  by  Dujardin  among  his  Paramecina.  Perty  con- 
structs a  family  out  of  this  genus,  along  with  CinetochUum  (vide  Cyclidium, 
p.  572),  Avhich  he  designates  CinetochiHna,  and  characterizes  as  animalcules 
having  a  mouth  on  the  upper  side,  surmounted  by  a  vibrating  valve  (Hke  a 
tremulous  eyelid).  Cilia  disposed  in  longitudinal  rows.  It  will  be  noticed 
that  the  mouth  is  described  to  be  on  the  upper  side  instead  of  the  under,  as 
stated  by  Ehrenberg,  with  whom  we  agree. 

The  anus  is  on  the  ventral  surface,  near  the  posterior  extremity.  Lachmann 
describes  two  flaps  to  the  mouth,  but  Perty  says  the  second  is  simply  an 
expansion  of  the  margin  of  the  mouth. 


Glaucoma  scintillans  (  CyclidiumBulla, 
M.)  (xxviii.  4-7). — Elliptical  or  ovate, 
colourless,  slightly  depressed ;  vacuoles 
large.  The  vibrating  flap  appears  to  be 
semi-oval  or  reniform  and  smooth,  and 
to  have  a  stiff"  margin.  The  cilia  are 
seen  by  employing  colour  or  by  pressing 


or  drying  the  animalcules  (xxiv.  300- 
302).  In  natural  and  artificial  infusions. 
1-280". 

G.  viriclis  (Duj.). — Green,  oval,  short; 
mouth  large,  situated  nearer  the  centre 
than  to  the  anterior  margin.  1-860"  to 
1-520".     In  rain-water  butts. 


Genus  CHILODON  (XXIV.  303-309  ;  XXIX.  48-59).— Body  irregularly 
oval,  flattened,  regularly  ciliated  :  frontal  region  produced  in  the  form  of  a 
broad  membranous  lip,  on  one  side,  resembling  a  beak ;  the  mouth,  situated 
at  its  base,  and  therefore  lateral,  is  furnished  with  a  tubular  fascicle  of  teeth. 
A  round  nucleus,  one  or  more  contractile  vesicles,  and  transverse  and  longi- 
tudinal self-division  have  been  observed. 

This  genus  along  with  Nassvia,  Prorodon,  and  two  newly-instituted  genera, 
CycJogramma  and  Hahrodon,  are  grouped  together  in  the  system  of  Perty, 
as  a  family  styled  '^  Decteria,''^  which  is  thus  characterized : — ^'  Mouth  beset 
with  a  circlet  of  fine  bristles.  In  the  first  three  genera  the  mouth  is  lateral ; 
in  the  remaining  two,  anterior." 

Stein  makes  Chihdon  distinct  from  Nassula,  by  its  body  being  compressed, 
having  a  distinct  upper  and  under  surface,  and  a  lip-like  process  above  the 
mouth. 


Chilodon  Cucullulus  (Kolpoda  Cucidlus, 
M.)  (xxiv.  303-307;  xxix.  48-59).— 
Body  depressed,  oblong  or  ovate,  rounded 
at  the  ends  ;  frontal  region  advancing  on 
the  right  side.  [Ehrenberg  states  he  has 
often  seen  the  straight  alimentary  canal, 
with  its  gi-ape-like  cells,  filled  with 
large  Naviculce.]  Contractile  vesicles 
from  two  to  three  ;  nucleus  large,  oval 
near  the  centre.  The  circlet  of  teeth 
was  stated  by  Ehrenberg  to  consist  of 
little  hard  wand-lilfe  bodies,  which  the 
creature  could  separate  so  as  to  admit 
into  its  mouth  large  living  bodies,  and 


afterwards  contract  or  close  upon  them 
(xxiv.  308,  309).  The  anus  is  at  one 
side  of  the  posterior  extremity.  In 
swimming,  or  creepmg  upon  the  surface 
of  ConfervcT,  the  mouth  is  timied  under 
or  below.  Its  motion  is  gliding ;  and  it 
does  not  revolve  in  swimming.  When 
the  water  is  coloured,  the  cilia  may  be 
easily  perceived,  and  their  disposition 
when  it  is  dried  up.  (Figs.  305  and  306 
exhibit  longitudinal,  and  307  transverse 
self-division.)  In  fresh  and  salt  water. 
1-1150"  to  1-140". 
This  species  has  received  a  close  in- 


OF  THE  TRVCHELINA. 


625 


vestigation  by  Stein.  The  circlet  of  teeth 
(bacillar  apparatus,  Lachmanii)  is  con-  I 
structed  of  no  actually  separate  portions  ! 
or  teeth,  as  Ehrenberg  supposed,  but  is  \ 
nothing  more  than  a  tliickened  cesopha-  ' 
gus  with  denser  rug?e,  or  folds,  of  a  chi-  [ 
tinous  composition.  From  its  lower  end  | 
a  digestive  tube  extends  to  nearly  the  ! 
centre  of  the  body.  | 

C.  tnicinatus.  —  Depressed,  oblong, 
rounded  at  the  ends.  The  right  side  of 
the  anterior  part  is  produced,  so  as  to 
appear  like  a  hook  or  beak.  In  vegetable 
infusions.     1-430". 

This  being  is,  in  Stein's  opinion,  a 
mere  variety  of  C.  Cuculhdus :  the  bulging  I 
out  of  the  side  has  a  somewhat  hook-like 
process ;  but  this  is  a  mere  accidental  re- 
sult follo's\'ing  the  process  of  longitudinal 
self-division  {Infus.  p.  130).  It  has  been 
seen  to  encyst  itself. 

C  aureus. — Ovate-conical,  tm'gid,  of 
a  golden  yellow  colour ;  dilated  and  ob- 
tusely rostrated  anteriorly,  attenuated 
posteriorly.     1-140". 

C.  oniatus. — Ovate  subcylindrical,  of 
a  golden  yellow  coloiu",  equally  rounded 
at  both  ends,  slightly  beaked  j  it  has  a 
bright  violet  spot.     1-180". 

The  violet  spot  spoken  of  has  no  di- 
stinctive peculiarity ;  it  is  not  a  normal 
coloured  gastric  fluid,  but  only  a  collec- 
tion of  granides,  the  same  as  in  Kassula 
elef/ans.  '. 

This  species,  together  \\dth  the  fore-  i 
going  C.  aureus  and  the  Nassula  aurea,  \ 
are  so  very  similar,  that  Stein  doubts  '• 
their  independent  natm'e,  and  is  more  dis-  \ 
posed  to  regard  them  as  developmental 
phases  of  the  same  being*. 

C.  depressus  (Perty). — Irregular,  with- 
out a  beak,  and  roimded  at  both  ends  ; 
compressed;  almost  colomless.     Trans- 
parent, with  greyish  contents.  Upper  and  , 
under  surfaces  equally  flat.    Tooth-cylin-  i 
der  very  evident.    Sv^atzerland.  1-120".    j 


Stein  states  that  the  body  is  bilateral, 
presenting  a  distinct  right  and  left  side, 
an  upper  (dorsal)  convex  and  a  lower 
(ventral)  flat  surface.  The  anterior  end 
is  much  flattened  and  transparent;  and 
being  curved  towards  the  left  side,  gives 
the  whole  being  a  somewhat  reniform 
flgm-e.  The  depression  on  this  side  is 
always  in  advance  of  the  middle  of  the 
body,  just  as  in  Paramecium  Colpoda  and 
Colpoda  CucuUulus.  The  anterior,  curved 
transparent  end  suimounts  the  body  like 
a  crescentic  process,  is  fm-nished  with 
longer  cilia  than  elsewhere,  and  may  not 
inaptly  be  called  the  lip.  Yibratile  cilia 
cover  the  body  in  regular  rows,  but  in 
very  young  specimens  are  invisible  ex- 
cept on  the  lip.  The  oval  nucleus  is 
hollowed  by  a  cavity,  within  which  is  a 
nucleolus.  Longitudinal  and  transverse 
fission  takes  place  in  individuals  of  all 
sizes.  The  former  advances  from  the 
posterior  extremity ;  the  oesophageal 
(dental)  cylinder  is  not  divided,  but  is 
produced  de  novo  in  the  newly  produced 
segment:  this  segment,  when  first  de- 
tached, is  the  CJiilodoii  uncimdus  (Ehr.). 
CJulodon  Cuculhdus  encysts  itself :  a  soft 
gelatinous  matter  is  first  thrown  out 
around  it,  which  hardens  into  the  cyst- 
wall  ;  during  this  process  the  superficial 
cilia  and  the  oesophageal  cylinder  disap- 
pear, and  at  length  an  oval  cyst,  with  a 
large  nucleus,  and  two  to  three  contractile 
spaces  alone  appear.  Gradually  a  cili" 
ated  embrj'O  is  developed  from  the 
nucleus,  resembling  in  external  charac- 
ters a  Cyclidiu7n  Glaucoma.  The  embryo 
escapes  from  the  parent  animal ;  and 
cysts  are  sometimes  found  containing 
tiie  parent  and  its  oflspriug  side  by  side 
within  it.  The  development  of  embryos 
may  go  on  until  the  nucleus  is  expended. 
The  size  of  the  germ  is  determined  by 
that  of  its  parent. 


Genus  NASSULA  (XXIV.  310,  311 ;  XXVIII.  2,  3,  11-15).  — Covered 
with  cilia ;  ovoid  or  oblong ;  turgid  and  prominent  in  front,  bnt  without  the 
expansion  or  beak  on  one  side  ;  month  lateral,  pro\dded  with  a  cii^clet  of  teeth, 
m  the  form  of  a  wheel  {nassa).  Xumerons  vacuoles  are  seen,  and  in  two 
species,  as  Ehrenberg  states,  the  discharging  orifice.  The  violet-colom-ed 
granular  spots  noticed  in  Chiloclon  oniatus  occur  also  in  the  species  oi  JS^assula, 
and  are  likewise  met  T\dth  in  Bursaria  vernalis,  TracheVms  Meleagris,  Amphi- 
leptus  margaritifer,  A.  Meleagris,  and  A.  longicollis.  "  They  resemble,"  says 
Ehrenberg,  "  the  vesicular  glands  around  the  stomachs  of  the  Rotatoria,  and 
are  probably  of  a  glandular  nature,  analogous  to  biliary  glands,  and  concerned 
in  the  process  of  digestion."  The  nuelens  is  large,  oval  or  spherical ;  and  there 
are  one  or  more  contractile  vesicles.     Only  transverse  self-division  has  been 


G26 


SYSTEMATIC  HISTORY  OF  THE  IXFUSORIA. 


observed.  They  are  found  in  stagnant  water,  especially  where  Conferva)  and 
Oscillatoria)  are  present. 

The  violet-colom\^d  supposed  digestive  glands  or  cells  are,  in  the  opinion 
of  others,  simply  vesicles  coloured  by  the  Oscillator ia  on  which  the  animal- 
cules feed  (p.  312). 

This  genus  and  the  preceding,  Chilodon,  are  very  closely  allied.  Stein 
finds  the  best  distinctions  between  the  two  in  the  rounded  body  with  the  ex- 
tremities obtuse  and  rounded  off,  in  the  case  of  Nassula,  and  in  the  flattened, 
compressed  body,  with  decided  ventral  and  dorsal  surfaces  and  with  a  lip-like 
process,  in  Chilodon. 

NASsrLA    elegans    (xxiv.   310,    311 


XXVIII.  11-15).  —  Cylindrical  or  oval, 
slightly  attemiated  in  front,  extremities 
very  obtuse.  It  is  white  or  greenish, 
spotted  with  violet  vesicles.  Vacuoles, 
containing  Clilamidomonads  or  other 
food,  may  often  be  observed ;  and  from 


of  a  brownish-green  colour,  variegated 
with  numerous  violet  vesicles.  The 
posterior  part  of  the  body  has  a  smaU 
excavation.  Ehrenberg  says,  there  are 
from  six  to  eight  groups  of  vesicles, 
forming  a  wide  circle  round  the  mouth, 
filled  with  a  -violet-coloured  juice,  which 


fifteen  to  twenty  rows  of  cilia  may  be  i  is  discharged  with  the  excreta,  and  ap- 
seen  on  one  aspect.  The  animalcule  pears  like  drops  of  oil,  but  soon  mixes 
s^^•ims  baclvward  and  forward,  turning  with  and  colom's  the  water.  It  swims 
upon  its  longitudinal  axis.  The  mouth  ,  rapidly,  rotating  also  on  itself,  but  this 
is  easilv  perceived  by  the  crn'rents  when  ouly  slowly.  Among  swinrming  clusters 
indigo  is  mixed  "v\uth  the  water  :  it  has  j  of  bsciUatorice.  1-96" ;  ova  1-4800".  It 
a    circlet    containing    twenty-six   little  |  has  been  seen  in  an  encysted  state. 


wands  or  teeth,  which  can  voluntarily 
diverge  or  converge  anteriorly.  Four 
round  contractile  vesicles,  placed  in  a 
row,  occur  on  the  dorsal  surface,  and 
doubtless  represent  four  expansions  of  a 
continuous  contractile  vessel  along  that 
region.  The  violet  vesicles  mentioned 
are  only  accidental  (i.  e.  not  necessary) 
collections  of  pigment  matter,  derived 
from  the  food  (see  p.  312).  When  self- 
division  ensues,  the  large  central  nucleus 
divides  (xxiv.  310,  311;  the  latter  is  a 
young  one).  With  Lemnge  and  Con- 
"fervse.  1-140"  to  1-120".  Nassida  ele- 
gans is  thus  characterized  by  Cohn : — 
Elongate  with  rounded  extremities; 
oesophagus  funnel-shaped;  no  cylinder 
of  teeth  present  as  in  N.  ornata.  Con- 
tractile vesicles  two ;  nucleus  elliptic, 
with  nucleolus  lodged  in  a  fossa  at  one 
end.  A  large  mass  of  violet  granides  on 
under  surface  posteriorly.  It  resembles 
but  is  smaller  than  Paramecium  AiireUa, 
and  has  a  similar  cuticle.  With  Bursaria 
trimcateUa  and  Ophryoglena  atra.  It  is 
smaller  than  N.  ornata.  Its  changes  of 
form  are  remarkable ;  often  dependent 
on  swallowed  joints  of  Oscillatorice.  Cilia 
very  closely  disposed. 

N.  ornata    {N.  viridis?,  D.)  (xxviii. 
65-71). — Ovate  or  globular,  depressed, 


N.  aurea. — Ovate-oblong,  nearly  cylin- 
drical, very  obtuse  at  the  extremities. 
Its  colour  varies  from  golden  yellow  to 
a  dark  brown.     1-120". 

Stein  hints  it  as  probable  that  this 
species  and  N.  viridis  (Duj.),  Chilodon 
aureus,  and  Ch.  ornatus  are  merely  dif- 
ferent stages  of  the  same  animal. 

N.  amhigua  (Stein)  (xxviii.  2,  3). — 
Rounded,  short  oval ;  extremities  equally 
rounded.  Entire  surface  covered  by  cilia 
in  longitudinal  rows.  The  wedge-shaped 
oral  opening  surmounts  a  -\'ery  wide  pha- 
rynx (tooth-cylinder,  Ehr.)  which  may 
be  easily  isolated.  The  contractile  vesicle 
acquires  a  stellate  figure  during  its  con- 
tractions and  dilatations,  like  that  of 
CJiilodon  ornatus.  The  contents  are  ori- 
ginally coloiuless,  but  become  tinted 
green,  blue,  and  red  successively,  during 
the  process  of  digestion  of  the  Oscillatoria 
it  feeds  upon.  It  occm-s  encysted,  in 
a  transparent,  resistant,  globular  cyst. 
Length  1-240"  ;  width  1-420".  ' 

N.  concinna  (Perty). — Ovate,  hyaline, 
transparent;  covered  everywhere  -^-ith 
fine  granules  having  an  annular  arrange- 
ment. Dental  apparatus  particularly  de- 
licate, more  evident  when  dried.  Cilia 
very  fine  ;  movements  sluggish ;  anal 
opening  at  posterior  extremity.    1-21G". 


Genus  LIOSIPHON  (Ehr.).— Turgid;  ciliated  throughout;  frontal  ex- 
tremity advanced  beyond  the  mouth,  and  not  auriculatc.  Mouth  opens  into 
a  tubular  membranous  pharynx,  pro-sided  with  a  cylinder  of  teeth. 


OF  THE  TKACHELINA.  627 

This  is  a  new  genus  instituted  by  Ehrenberg.  Its  essential  distinction  from 
Nassida  is  not  pointed  out,  the  only  one  indicated  being  the  prolongation  of 
the  frontal  region  beyond  the  oral  apertui-e. 

lAOSip-no^  Strompkii. — Obtuse,  ovate ;  |  pharynx  of  a  clavate  outline.  1-36'". 
of  a  variegated  green  coloiu' ;   tube  of  |  With  Oscillatorics. 

The  genera  named  by  Dujardin,  ha\-ing  a  near  affinity  ^ith  Bursaria,  are 
Plagiofoma,  Kondylostoma,  Oj^yalina,  and  Fanophrys.  Two  others,  Acineria 
and  Pelecida  (Duj.),  are  described  as  allies  of  Trachelius. 

Genus  OPALINA. — Already  described  in  the  Astomatous  family  Opalinaea 
(vide  p.  569). 

Genus  PLAGIOTOMA  (Duj.).— Body  very  flat  or  lamellar,  very  flexible, 
irregularly  oval ;  sinuous  or  emarginate  on  one  side,  and  sometimes  angular 
behind ;  covered  with  cilia  in  regular  rows ;  mouth  lateral,  near  the  middle, 
at  the  bottom  of  the  depression,  with  a  row  of  strong  and  very  numerous  cilia 
in  advance  of  it  on  its  anterior  margin,  having  a  comb-like  aspect. 

of  a  yellowish  grey  colour  from  contained 
molecules.  Owing  to  its  want  of  trans- 
parency, tlie  fine  short  cilia  are  visible 
only  around  the  peripherv.  Motion  ex- 
tremely languid,  oscillating  and  revolv- 
ing. 1-260".  In  the  interior  of  Ano- 
donta  Cellensis. 


Plagiotoma  Lumhrici  =  Paramecium 
compressum  (Ehr.). — Stein  shows  this  to 
be  a  true  Bursaria  (see  p.  622). 

P.  concha  rum  (Perty)  =  Leucophrys 
Anondontce  (Ehr.). — This  and  the  fore- 
going are,  in  Stein's  opinion,  Opalince 
(see  p.  670). 

P.  (?)  difformis. — Irregular,  thick,  and 


Genus  K0:N"DYL0ST0MA  (Duj.).— Body  more  or  less  elongated,  cylin- 
drical or  fusiform,  rather  crescentic,  with  obtuse  and  flattened  ends  ;  mouth 
very  large,  bordered  by  very  strong  cilia,  and  placed  on  one  side  near  the 
anterior  extremity ;  surface  obliquely  striated  and  ciliated.  It  swallows  its 
food,  consisting  of  other  animalcules  or  of  vegetable  debris,  rather  after  the 
manner  of  Plana  rice  than  of  Paramecina ;  for  it  does  not  draw  it  in  by  the 
action  of  its  cilia  in  producing  a  vortex.  It  lives  only  in  smooth  and  pure 
sea- water  among  Algse,  itc. 

KoNDYLOSTOMA  patcns. — Body  white, 
or  colom-ed  by  the  food  received ;  at  times 
vermiform,  at  others  fusiform,  and  often 


modified  in  figure  by  the  bulk  of  food 
swallowed. 


Genus  PAIN'OPHEYS  (Duj.)  (XXYI.  33).— Ciliated  throughout;  oval, 
depressed,  contractile  ;  becoming  ovoid,  or  even  globular,  during  contraction ; 
smface  marked  by  straight  or  oblique  ciliated  striae,  crossing  one  another ; 
mouth  lateral.  Dujardin  writes — ''  Being  desirous  of  characterizing  Bur- 
saria by  the  row  of  large  cilia,  en  moustache,  which  lead  to  the  mouth,  I  have 
thought  it  right  to  establish  a  new  genus  for  certain  Biirsarice  of  Ehrenberg, 
which  are  devoid  of  this  character,  and  whose  mouth  is  surrounded  by  only 
ordinary  cilia."  UnUke  the  Paramecia,  they  have  no  anterior  oblique  fold 
or  fossa,  and  are  able  to  contract  themselves  into  a  ball.  They  differ  from 
Holophrya  by  their  lateral  mouth.  They  live  either  in  fresh  smooth  water, 
or  in  sea-water  among  plants. 

In  Perty's  system  it  constitutes  a  member  of  the  family  Paramecina ;  and 
this  is  its  tnie  position,  if  the  cilia  are  throughout  of  equal  length.  Indeed 
the  characters  assumed  to  be  distinctive  of  it  from  Paramecium  appear  to  us 
inconclusive.  A  lateral  fold  or  vestibulum  leading  to  the  mouth  is  not  entirely 
wanting,  although  less  developed  than  in  most  Paramecia  ;  and  as  to  their 

2s2 


62S 


SYSTEMATIC  HISTORY  OF  THE  ITI^FUSORIA. 


greater  contractile  power,  this  really  is  questionable,  and,  if  true,  is  not  a 
proper  generic  character. 


Panopitrys  C7in/salis  (xxvi.  33). — 
Ovoid,  oblong,  depressed,  mouth  accom- 
panied by  an  enlargement,  and  placed 
near  the  front  exti-emity.  1-145"  In 
sea-\vater. 

P.  rubra  (?). — Eeniform,  covered  with 
fine  cilia,  and  provided  with  a  lateral 
mouth  near  the  front  extremity.  1-370" 
to  1-325".  In  sea- water.  Only  pro- 
visionally named. 

V.farcta. — Ovoid,  oblong,  filled  with 
particles  of  a  green  reddish-yellow  hue, 
or  of  various  mingled  colours ;  mouth 
lateral,  placed  between  the  centre  and  the 
anterior  third  of  the  body.  Its  outline 
is  very  changeable,  its  movements  rapid. 
The  colour  is  seldom  green.  1-145"  to 
1-95".  In  marsh- water  among  plants. 
I  think  it  is  the  animalcule  described 
under  three  names  by  Ehrenberg,  viz. 
Bursaria  vernalis,  B.  Icucas,  a,nd  B.Jlava, 
and  is  probably  the  same  as  Leucophra 
virescens  of  MiiUer. 

Although  Perty  acquiesces  in  the  be- 
lief that  the  yellow-coloured  specimens 
of  this  species  are  the  Bursaria  Jiava 
(Ehr.),  yet  he  thinks  Dujardin  wrong 
in  claiming  B.  leucas  and  B.  vernalis  as 
varieties. 

P.  conspicua  (Perty). — Large ;  cylin- 
drical, scarcely  smaller  behind  than  in 
fi'ont ;  mouth  round.  Coloured  by  food 
dark  green.  Swims,  revolving  at  the 
same  time  v^-ith  moderate  speed.  1-95". 
In  peaty  ponds  \ni\\  Lemnpe. 

P.  sordida  (Perty). — Cylindrical,  more 
or  less  elongated ;  colour  dark,  earthy- 
brown.  Mouth  small.  Cilia  covering  the 
body,  fine.  The  position  of  the  internal 
molecules  varies  even  during  examina- 
tion, and  the  figure  with  them.  1-180" 
to  1-96".     Among  Charae. 

P.  (jriseola  (Perty)  (xxviii.  31).  — 
Broad,  distended ;  grey,  but  transparent, 
with  a  tine  reticulate  appearance  ;  mar- 
ginal concentric  stride.  Sometimes  occu- 
pied   with    chlorophyll-granules,  when 


it  much  resembles  OijhrijogJena  griseo- 
virens.  The  mouth  appears  like  an 
elliptic  fold  in  a  shallow  fossa  in  the 
anterior  half.  It  swims  and  turns  on 
itself  with  much  activitv.  Transverse 
fission  observed.  1-300"  to  1-108". 
Among  deca^-ing  plants. 

P.  zonalis  (Perty). — Elongated,  ovate- 
cylindrical  ;  h^-aline,  with  a  central  zone 
of  dark  molecules.  Extremities  equally 
wide,  and  rounded.  Fissure  of  the  mouth 
beset  with  stronger  cilia.  Movements 
rather  sluggish.  Body  ciliated  through- 
out.    1-168". 

This  scarcely  seems  a  true  Panophrys ; 
for  the  oral  cilia  are  said  to  be  larger 
than  those  on  the  body,  contrary  to 
Dujardin's  characters  of  the  genus. 
Moreover  its  chief  peculiarity,  viz.  the 
zone  of  darker  granules,  is  an  insuificient 
specific  feature ;  and  when  we  are  told 
by  Perty  that  he  has  only  once  seen  a 
small  specimen,  this  supposed  species  has 
few  claims  to  notice. 

P.  paramecioides  (Perty).  —  Cylindri- 
cal, slightly  curved,  its  posterior  end 
somewhat  thicker  than  the  anterior; 
colourless ;  rows  of  cilia  very  numerous 
and  fine.  Its  molecular  structure  re- 
sembles that  of  Paramecium  Aurelia. 
Movements  energetic,  twisting.  The 
mouth  is  placed  in  a  shallow  fossa  on 
one  side  of  the  body.  1-108".  An  un- 
common form  in  Switzerland. 

There  is  scarcely  anything  in  the  above 
description  which  is  not  compatible  with 
the  belief  that  the  animalcule  in  ques- 
tion is  either  a  Bursaria  or  a  Parainecium. 
Moreover,  reference  to  Perty's  figm-es 
lends  no  aid  to  the  determination  of  tlie 
question ;  and  we  must  confess  our  in- 
ability to  find,  in  his  illustrations  of  the 
gemisPanophri/s,  any  sufficiently  detailed 
particulars  to  enable  us  to  distinguish 
either  of  the  species  named  as  members 
of  it  from  probable  representatives  of 
allied  genera. 


Genus  BLEPHARISMA  (Perty)  (XXYIII.  33,  34).— Body  compressed, 
lancet-shaped,  ^vith  a  pointed  posterior  extremity,  whence  a  deep  fossa  ex- 
tends as  far  as  the  middle,  fringed  with  longer  and  straighter  cilia  than  cover 
the  rest  of  the  body.  The  internal  molecules  are  disposed  in  longitudinal 
rows,  over  which  the  very  fine  and  inconspicuous  cilia  are  arranged. 


Blephahisma  hyalinum  (xx^t:ii.  33, 
34). — Colourless,  except  when  occupied 
by  swallowed  chlorophyll-particles.  Body 
thin,  flexible,  and  changeable  in  form; 


older  specimens  are  broader.  Movements 

varied  and  tolerably  rapid.     Sometimes 

a  few  large  and  non-vibratile  filaments 

i  appear    to    issue   from    the    oral   fossa. 


OF  THE  TKACHELIXA. 


629 


Among  Confervse  and  Lemnce ;  not  com-  '  specimens    paler, 
mon.  _  1-210"  to  1-144" 

B.  persicinum  =  Trichoda   striata   (?)     preceding;  rare. 
(MiilL). — Colour  reddish-yellow;  young  ' 


Fission    transverse. 
i\.t  Bern,  with  the 


Genus  ACINEEIA  (Duj.)  (XXVI.  21  a,  ft).— Body  oblong,  depressed,  or 
lanceolate,  with  a  row  of  cilia  extending  forwards  on  one  side,  which  is  curved 
like  a  sabre.  Distinguished  from  TracJielius  by  the  disposition  of  the  row  of 
cilia  and  the  ciu'vature  forwards.  As  in  TracJielius,  the  examples  of  this 
genus  seem  destitute  of  a  mouth,  and  in  this  respect  they  especially  differ 
from  those  of  Pelecida. 

AciNEEiA  incurvata  (xxvi.  21  a,  b). —  j  pears  to  be  -wdthout  a  reticulated  and 
Contractile,  oblong,  compressed,  almost  '  contractile  integimient. 
lamellar,  roimd  or  obtuse  behind,  con-  A.  acuta. — Diaphanous,  with  granules 
tracted  and  curved  m  front ;  a  row  of ,  dispersed  in  its  interior ;  oblong,  com- 
cilia  runs  along  the  convex  edge ;  and  ]  pressed,  pointed  at  its  two  ends  ;  or 
there  are  five  or  six  granular  stripes,  lanceolate,  with  one  side  more  convex 
and  one  or  more  variable  vacuoles.  |  in  front  and  fringed  with  cilia.  1-580". 
1-590".     In  the  Mediterranean.     It  ap-  |  In  pond-water. 


Genus  PELECIDA  (Duj.). — Body  iiexible,  contractile,  oblong,  compressed, 
roimded  behind,  curved  in  the  form  of  an  axe  in  front,  ciliated  throughout, 
and  fiu-nished  with  a  mouth  either  visible  or  indicated  by  the  various  objects 
met  with  in  the  interior  of  the  animals. 

The  animalcule  assumed  as  the  type  of  this  genus  is  the  Loxodes  Rostrum 
of  Ehrenberg.  It  is  stated  to  difler  from  the  Paramecin  a  by  the  absence  of 
a  contractile  integument.     Perty  introduces  it  into  his  system. 

to  four  longitudinal  folds.     Colomiess. 


Pelecida  Rostrum  (Duj.)  =  Loxodes 
Rostrum  (Ehr.). 

P.  costata  (Perty). — Small;  with  two 


1-320"  to  1-210".    Bern.    In  ponds,  &c. 


Genus  LEMBADIOX  (Perty)  (XXVIII.  50,  51).— Body  oval,  rather  ven- 
tricose;  with  one  more  or  less  deep  and  wide  furrow  ninning  nearly  the 
entire  length  of  the  ventral  siuface.  About  twenty  rows  of  cilia  on  the  dorsal 
aspect ;  on  the  margin  of  the  furrows,  and  at  the  posterior  extremity,  are 
longer  cilia. 

Internally  from  two  to  eight  translucent  large  round  vesicles  are  visible. 
In  Perty' s  classification  this  genus  is  a  member  of  the  family  Biu-sarina 
(see  p.  621). 


Lembadion  'hullimim= Bursaria  hid- 
lina  (Miill.)  (xxviii.  50,  51). — Hyaline, 
filled  with  veiy  delicate  molecules ;  the 
spherical  and  often  very  large  internal 
vesicles  differ  much,  both  in  number  and 
position.  A  proboscis-like  process  occiu's 
at  the  anterior  extremity.  Movement 
tolerably  quick,  often  gyrating.  Trans- 
verse fission  has  been  observed.  1-240" 
to  1-190".  In  spring- water.  Bern,  Lu- 
gano, &c.  Ehrenberg  has  erroneously 
cited  the  Bursaria   hullina    (Schranlc), 


which  is  identical  with  the  present 
species,  as  the  same  organism  as  his 
Glaucoma  scintillans. 

L.  (?)  duriusculum. — Colourless,  ellip- 
soidal, with  a  keel  or  ridge  along  its 
upper  siu'face ;  the  under  surface  some- 
what concave.  It  appears  tolerably  stifi" 
and  firm  in  consistence ;  the  cilia  are 
very  fine,  and  its  movements  sluggish. 
1-720"  to  1-620".  The  position  of  this 
animalcule  in  this  genus  is  doubtful. 


Genus  HABMODIPUS  (Perty). — Body  globular,  having  a  moveable  elon- 
gated lip  or  proboscis  anteriorly. 

It  is  a  member  of  the  Trachelina  (Perty),  and  is  represented  as  being  in 
part  equivalent  to  Amj)hUei)tus  (Duj.)  and  to  Trachelius  (Ehr.). 


630 


STSTEilATIC  HISTOEY  OF  THE  IJ^^FUSOETA. 


Harmodirus  Ovum.  —  The  proboscis 
is  not  so  much  a  process  of  the  substance 
of  the  body,  as  like  a  jointed  finger  or 
segment ;  it  has  a  jerking  movement  in 
one  direction,  yet  it  appears  frequently 
stretched  as  a  stiff  process  from  one  side. 
Cilia  extremely  tine;  thirty  rows  have 
been  counted  on  one  side ;  they  are  most 
evident  near  the  proboscis.     Diastrophy 


may  be  frequently  witnessed.  1-180"  to 
1-36".  In  fi-esh  and  bog  water,  with 
Lemnse.  This  species  is  doubtless  the 
same  as  Traclielius  Ovum  (Ehr.)  and  Am- 
phUeptus  Ovum  (Duj.)  ;  and  we  do  not 
conceive  the  necessity  of  elevating  it  to 
the  rank  of  a  genus  on  account  of  the 
slight  differential  character  of  the  pro- 
boscis, as  Perty  has  done. 


Genus  CINETOCHILUM  (Perty)  (XXYIII.  35).— Small,  short,  elliptical, 
somewhat  compressed ;  vibratile  flap  on  the  posterior  half. 

CixETOCHiLUM  margaritacenm=  CycUcUum  margaritaceum  (Ehr.)  (see  p.  573). 


Genus  CYCXOGPAMMA  (Perty)  (XXVIII.  36, 37).— Body  small,  ha^ing 
the  form  of  Paramecium ;  with  concentric  striae  on  the  margin,  and  a  lateral 
depression  near  the  fore  part,  where  a  mouth,  with  an  obsciu'e  but  peculiar 
apparatus  of  from  four  to  seven  bristles,  is  apparent.  It  is  a  member  of  a 
family  called  Decteria  (see  j).  624). 


Cyclogramma  ruhens. — Colom*  yel- 
low, seldom  green,  or  reddish-white. 
Mostly  rather  compressed ;  rarely  sub- 
cylindrical.  Cilia  very  tine,  with  the 
exception  of  those  on  the  margin,  which 


i  are  arranged  in  circular  rows.  Move- 
ment commonly  sluggish.  The  dental 
apparatus  is  evident  in  some  examples, 
but  undiscoverable  in  others.  1-480"  to 
1-300".     Ponds,  Bern. 


FAMILY  YIII.— OPHRYOCERCIXA. 

Polygastria  without  lorica ;  alimentary  canal  with  two  distinct  orifices,  of 
w^hich  only  the  anal  one  is  terminal.  Although  their  motion  is  rapid,  ciha 
are  perceived  near  the  mouth  only,  though  they  probably  cover  the  body ; 
the  long  neck  assists  in  swimming,  and  indeed  is  sufficient  alone.  Granules 
(ova?)  are  seen  in  all  the  species,  and  a  contractile  vesicle  in  T.  biceps. 
Self-division  probable,  but  not  observed. 

No  such  family  as  Opluyocercina  enters  into  the  system  of  Dujardin,  the 
animalcules  composing  it  being  all  referred  to  the  genus  Lacvymaria  (see 
p.  609)  ;  and  consequently  that  oi  Traclielocerca  is  merged  in  the  same. 

On  the  other  hand,  Perty  retains  this  family  name,  but,  unlike  Ehrenberg, 
comprehends  in  it  both  TracJielocerca  and  Lacrymaria  :  moreover  he  assigns 
to  Trachelocerca  a  ^vider  generic  signification,  so  that  it  includes  also  Phialimi 
(Ehr.).  Again,  this  family  is  the  representative  of  one  of  his  three  chief 
sections  of  Ciliata,  viz.  Metabolica,  thus  defined : — "  Animalcules  very  con- 
tractile, undergoing  protean  changes  of  figiu-e  by  the  expansions  and  con- 
tractions of  the  body.  Cilia  scarcely  visible  upon  the  body,  but  clearly  seen 
on  its  neck-like  process."  Laehmann  describes  the  oesoj^hagus  in  this  family 
to  be  collapsed,  or  invisible,  except  during  the  passage  of  food. 

Genus  TRACHELOCEECA.— Characters  as  above. 

Trachelocerca  0/or(T7&noP;-ofe?^s,  I  the   vessel    containing    it,   and   twines 


Cygmis  et  Ohr,  M. ;  Lacrymaria  Olor, 
D.)  (XXIV.  317,  318,  319).— Spindle- 
shaped  ;  neck  very  long  and  flexible, 
terminated  by  a  dilated  and  ciliated 
mouth.  The  surface  is  beautifidly  reti- 
culate in  this  and  the  following  species. 
This  creature  creeps  at  the  bottom  of 


itself  gracefully  about  Confervae,  or  the 
roots  of  Lemnse,  but  swims  awkwardly. 
It  elongates  and  contracts  its  neck  at 
pleasure,  and  is  altogether  an  interesting 
object  for  the  microscope.  Greatest 
length  1-36".  It  has  been  found  en- 
cvsted. 


OF  THE  ASPIDISCIJ^A  AND  KOLPODEA. 


631 


T.  viricUs  (Zacri/maria  riridis,  D.). — 
Spindle-shaped,  neck  simple,  very  mo- 
bile, long,  and  dilated  at  the  mouth, 
which  has  a  ciliated  lip.  Amongst 
Lemnse.  Length  1-120" ;  contracted 
1-380". 

Perty  changes  the  specific  name  to 
^' li/i(/uifera,^^  and  has  the  very  good 
reason  for  so  doing  that  the  green  colour 
is  no  distinction,  because  it  is  often 
and,  besides  various 


changed  to  bro^^Ti 


or 


intennediate  tmts,  is  at  times  greyish 
colourless.     Unlike  T.  Olor,  the  neck  is 
surmounted  by  a  moveable  flap  or  pro- 


cess, styled  a  tongue,  fringed  wdth  di- 
stinct cilia.  Pertv  speaks  of  specimens 
1-72"  in  length. 

T.  biceps.  —  Spindle-shaped,  white  ; 
neck  long,  forked,  each  segment  with  a 
mouth.     1-190". 

This  can  have  no  claim  as  a  species, 
since  it  is  evidently  nothing  more  than 
an  animalcule  in  the  act  of  longitudinal 
fission,  not  far  advanced. 

T.  Saf/{Ua=  Vibrio  Sagitta  (M.).— Fu- 
siform, white  ;  neck  very  long ;  head  ter- 
minal, opaque,  1-120".  North  Sea  and 
Baltic. 


FAMILY  IX.— ASPIDISCINA. 

(XXV.  321-323.) 

Distingiiislied  from  the  preceding  family  by  the  presence  of  a  loriea.  The 
alimentary  canal  has  two  orifices,  of  which  the  discharging  one  only  is  terminal. 
The  loriea  is  firm,  very  transparent,  and  combustible,  somewhat  resembling 
the  shell  (carapace)  which  covers  the  back  of  a  tortoise;  it  projects  anteriorly 
a  little  beyond  the  body.  Long  flexible  bristle-like  organs  attached  to  the 
abdomen  enable  the  animalcnles  to  climb,  while  the  delicate  cilia  near  the 
month  serve  both  as  swimming  and  purveying  organs.  Xumerous  vacuoles 
have  been  filled  with  coloiu-ed  food  by  Ehrenberg,  w^ho  has  also  seen  the 
discharge  of  matter  posteriorly.  An  oval  nucleus  and  a  contractile  vesicle 
occur  in  both  species.  Miiller  observed  self-division,  but  mistook  it  for 
copulation.     They  are  not  developed  in  large  masses. 

Genus  ASPIDISCA. — Characters  as  above. 

underneath.    Amongst  LemnaB  and  Con- 
fervffi.     1-1000"  to  1-57G". 


AsPiDiscA  lynceus  {Triclioda  hjnceus, 
M.). — Loriea  nearly  circular,  truncated 
at  the  posterior  end,  and  formed  into  a 
hook  or  beak  in  front.  Mouth  furnished 
with  very  delicate  cilia  ;  five  or  six 
bristles  (styles)  are  affixed  posteriorly, 
and  fiom  five  to  eight  hooks  anteriorly, 
whereby  a  resemblance  to  Euphtes  and 
Stylonyclda  is  established.  A  contractile 
vesicle,  near  the  mouth,  and  twenty 
vacuoles  have  been  seen.  \Vhen  burnt 
upon  platina  no  traces  remain.  Gene- 
rally  STvims    or   creeps   w^ith    its   back 


Stein  asserts  that  it  is  an  error  to 
detach  this  species  from  Euphtes,  T\-ith 
which  it  has  the  closest  affinity,  and  to 
elevate  it  to  the  rank  of  a  family  in 
immediate  contiguity  with  Colpodea, 
with  which  it  has  no  natural  relation. 

A.  denticulata. — Loriea  nearly  circular, 
under  side  truncated  and  denticidated, 
fiat ;  back  arched.  The  iincini  are  visible 
only  when  climbing,     1-76". 


FAMILY  X.~KOLPODEA  or  COLPODEA. 

(XXIV.  312-316 ;  XXY.  325-335  ;  XXYI.  23,  32,  33 ;  XXYIIL  24-26, 
31,  33,  34;  XXIX.  19,  20,  25-47.) 

Animalcules  ciliated  throughout ;  the  cilia  disposed  in  longitudinal  series, 
and  either  of  uniform  length  throughout,  or  of  larger  growth  at  particular 
parts,  especially  about  the  mouth.  Both  mouth  and  anus  demonstrable, 
always  lateral,  sometimes  situated  on  the  same  side,  at  others  on  opposite 
sides  of  the  body. 

Except  AmiDliUeptus  and  UroJeptus,  the  other  genera  have  both  the  mouth 
and  anus  on  the  ventral  surface.  In  the  former  genus  Lachmann  likewise 
describes  the  oesophagus  to  be  collapsed,  except  during  the  passage  of  food, 
when  it  presents  the  appearance  of  a  canal.     In  all  other  genera  of  Kolpodea 


632  SYSTEMATIC  HISTORY  OF  THE  INFrSORlA. 

the  oesophagus  is  distinct,  of  considerable  length,  and  cihated,  but  not  thick- 
ened at  any  portion  so  as  to  produce  the  appearance  of  a  dental  cylinder  "  or 
bacillar  apparatus."  Coloured  food  received  by  all  the  species.  Contractile 
vesicles  one  or  two  in  number,  and  in  Paramecium  of  a  stellate  figure. 
Nucleus  usually  rounded,  oval  or  reniform.  A  red  spot,  eye-speck  or  stigma, 
is  common  in  OphryogUna.  Propagation  takes  place  by  fission,  which  may 
be  either  transverse  or  longitudinal ;  by  the  production  of  single  living  em- 
bryos (at  least  this  occurs  in  Paramecium  and  Colpocla) ;  and,  in  Perty  and 
Carter's  opinion,  by  numerous  germs  or  internal  ova.  The  encysting-process 
has  also  been  seen  in  all  the  genera  except  Uroleptus.  The  integument  of 
Kolpodea  is  reticulated,  presenting  a  beautiful  diamond-pattern,  and  ha^dng 
a  cilium  seated  in  the  centre  of  each  lozenge. 

The  Kolpodea  are  highly- organized  Ciliata,  although  inferior  in  this -respect 
to  the  Yorticellina.  The  single  ciixumstance  of  the  limitation  of  the  ciha  to 
the  head  in  the  latter  family  is  of  itself,  according  to  a  well-recognized  law 
of  animal  life,  an  intimation  of  a  higher  grade  of  organization. 

The  genera  are  disposed  as  follows : — 

CM      .         i      T       i  f  absent  posteriorly  Kolpoda. 

Short  protruding  tongue.  J 

^  ^^  [  present  everywhere     Paramecium. 


Eye  absent. 


No  tongue 


With  tail  and  proboscis Amphileptus. 

With  tail,  no  proboscis  Uroleptus. 

Eye  present     Ophryoglena. 

This  family  corresponds  generally  with  that  of  the  Parameciens  or  Para- 
mecina  (Duj.),  thus  defined: — Body  soft,  flexible,  variable  in  form,  but 
mostly  oblong  and  more  or  less  flattened ;  provided  with  a  loose,  reticulated 
integument,  upon  which  numerous  \ibratile  cilia  are  disposed  in  regular 
series.  Mouth  present.  The  genera  included  are  : — Lacri/maria,  PleuronemUf 
Glaucoma,  KoljDOcla,  Paramecium,  Ampliilep>tus,  Loxopliyllum,  Chilodon, 
Panoj^hrys,  NassuJa,  Holojjlirya,  and  Prorodoa. 

Dujardin  observes  that  Lacrymaria  and  Pleuronema  should  probably  be 
placed  in  a  distinct  family,  since  the  mouth  is  rather  presumed  than  demon- 
strated in  them.  Tliis  is,  however,  a  reason  which,  in  the  present  day,  would 
not  be  held  valid,  as  the  evidence  of  a  mouth  is  equally  strong  in  them  as  in 
others  of  the  genera  enumerated. 

Perty  also  has  constructed  a  family  Paramecina,  containing  the  genera 
Ophryoglena,  Panophrys,  Paramecium,  Bhp>liarisma,  and  Colpocla,  and  briefly 
characterized  as  having  the  body  covered  with  longitudinal  rows  of  cilia,  and 
a  lateral  mouth  often  ^\dthin  a  fissure.  Lastly,  Mr.  Carter  has  instituted  a 
new  genus,  named  Otostoma,  referable  to  this  family,  being  a  close  ally  to 
Paramecium. 

Genus  KOLPODA  or  COLPODA. — Body  ovoid,  sometimes  reniform ;  a  Httle 
tongue-like  member  (a  tuft  of  cilia)  inserted  in  the  oral  ca\ity ;  ciliated  in 
front  and  partly  beneath ;  eye-speck  wanting.  The  mouth,  posterior  termi- 
nation of  the  alimentary  canal,  and  numerous  gastric  cells  may  be  demon- 
strated by  coloured  food ;  the  two  orifices  are  both  on  the  ventral  siuface. 
''Ova,"  adds  Ehi-enberg,  "  occur  in  delicate  strings,  forming  a  sort  of  network ; 
and  their  extrusion  has  been  seen  in  one  species.  A  round  contractile  vesicle 
is  observable  in  two  species,  and  two  such  in  another.  A  large  round  or 
oval  gland  (nucleus)  is  found  in  the  centre  of  the  body."     Self-division  botli 


OF  THE  KOLPODEA. 


633 


transverse  and  longitudinal.  Tlieii-  motion  is  not  active,  the  locomotive  cilia 
being  few. 

Dujardin,  spcaldng  of  this  genus,  says,  '*  Among  Ehrenberg's  Koliwdce, 
which  should  possess  a  short  tongue,  and  be  ciliated  only  on  the  ventral 
siu'face,  but  one  species,  K.  CucuUus,  is  with  certainty  numbered  ;  the  K.  Ren, 
and  A'.  CuculUo  have  been  referred  to  the  genus Zo.roc?^5,  where,  indeed,  we  still 
leave  them.  However,  Ehrenberg  places  among  the  Paramecia,  under  the 
appellation  of  P.  Koljyoda,  some  large  animalcules,  ciliated  throughout,  which 
we  regard  as  only  more  developed  forms  of  Kolpoda  CucuUus.^' 

Stein  expresses  himself  on  these  views  thus  {Infus.  p.  131)  : — "  Under  the 
name  of  Colpoda  CucidlusD\\]^Y(\in  has  described  the  Paramecium  (?o7poc?a,Ehr., 
appearing  either  to  be  unacquainted  with  the  true  Colpoda,  or  to  have  looked 
upon  it  as  an  undeveloped  state  of  Paramecium  Colpoda.^^  The  distinctive 
characters  between  these  two  animalcules  and  Chilodon  Cucidhdus  are  thus  laid 
down : — All  these  thi'ee  forms  are  similar  in  outline,  Chilodon  Cucidhdus  and 
Colpoda  CucuUus  being  really  in  most  respects  imdistinguishable.  Paramecium 
Colpoda  is  devoid  of  the  peculiar  lip,  but  has,  on  the  other  hand,  an  expanded 
anterior  extremity  (brow),  lying  over  and  above  the  oblique  infundibulum,  on 
one  side  of  the  body,  leading  to  the  mouth.  Chilodon  Cucidhdus  displays,  by 
the  action  of  chemical  reagents,  about  the  middle  of  its  ventral  surface  its 
special  form  of  pharynx  or  oesophagus :  it  is,  besides,  ciliated  all  over ;  but  this 
is  a  criterion  determinable  with  difficulty,  particularly  in  young  specimens. 
In  Colpoda  CucuUus  the  mouth  is  quite  simple,  and  placed  in  the  lateral  de- 
pression ;  the  distribution  of  the  cilia  is  always  partial,  chiefly  limited  to  the 
Up.  In  Paramecium  Colpoda  the  mouth  (oral  aperture)  hes  at  the  bottom  of 
a  deep  longitudinal  fold  (fissui-e)  on  one  side  of  the  body,  is  boimded  by  two 
very  motile  hps,  and  conducts  into  a  short,  thin,  walled,  cihated  oesoj)hagus  ; 
the  nucleus  is  oval,  large,  homogeneous,  and  finely  granular ;  and  the  body  is 
very  evidently  ciliated  all  over. 

KoLPODA  Cucidlus  (M.)(xxv.  324-327; 
xxix.  35-47).  —  Turgid,  slightly  com- 
pressed ;  kidney-shaped.  The  concavity 
in  which  the  oral  aperture  is  situated  is 
occupied  by  a  process  called  by  Ehren- 
berg a  "tongue,"  but  which  Stein  has 
shown  to  be  a  bundle  of  longer  cilia. 
The  cilia  are  not  distributed  over  the 
whole  sm-face,  but  limited  to  the  convex 
sm-face  of  the  anterior  half,  auo-mentino- 


in  size  as  they  approach  its  elongated  and 
expanded,  wide  lip-like  or  frontal  pro- 
cess above  the  oral  fossa,  and  to  a  ridge 
extending  downwards  and  baclavards 
from  that  fossa.  The  granides  in  the 
interior  are  frequently  so  numerous  as 
to  render  it  opaque ;  they  also  give  it  a 
grey  coloiu.  The  single  contractile  ve- 
sicle is  seated  close  to  the  posterior 
extremity ;  the  nucleus  is  a  circular  disc 
containing  a  nucleolus,  and  nearly  cen- 
tral in  position.  This  animalcule  has 
not  been  seen  to  undergo  fission  whilst 
in  the  free  state ;  the  process,  however, 
goes  on  after  it  has  encysted  itself,  with 
various  modifications  in  the  residts  (see 
Part  I.  p.  350).  Ehrenberg  having 
adopted  the  notion  that  the  breaking  up 


of  a  portion  of  the  animalcule  was  an 
act  of  oviposition,  thought  to  further 
establish  it  by  remarking  the  presence 
of  numerous  Monadiform  beings  about 
it,  which  he  concluded  were  developed 
from  the  supposed  ova,  as  the  first  phase 
of  futui'e  Colpodcs.  Such  an  interpreta- 
tion has  no  evidence  to  support  it,  and 
is  rejected  by  Stein,  (xxv.  324,  the 
normal  form ;  fig.  325  represents  the 
animalcule,  as  Ehrenberg  conceived,  de- 
positing its  ova  in  a  net-like  mass,  or, 
as  others  woidd  interpret  it,  in  process 
of  diffluence  -,  and  figs.  326,  327,  yoimg 
animalcules,  which  resemble  Trichoda 
pyriformis.)  Conmion  in  vegetable  in- 
fusions.    1-1800"  to  1-280". 

K.  (?)  Ren.  —  Ovate,  cylindrical,  kid- 
ney-shaped, and  rounded  at  the  ends. 
In  river-water.     1-288". 

K.  (?)  CuculUo  (lSL)=Zoxodes  Cueullio, 
(Perty). — Compressed,  plane,  elliptical, 
slightly  sinuated  anteriorly.  Ehrenberg 
remarks  that  neither  cilia  nor  tongue- 
like member  was  observable  by  him, 
and  that  its  generic  situation  is  there- 
fore uncertain.  Perty,  however,  has 
noticed  such  a  process.     1-900". 


634 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


K,  Luganensis  (Perty). — Large,  broad, 
slightly  convex  oil  one  side.  Oral  in- 
fuudibulum   deep.     Rows   of  cilia   un- 


usually  numerous 
internal  corpuscles  green 
is  probably  a  Kolpoda. 


Movements    slo^\ 


1-130".     It 


Genus  PARAMECIUM  (XXV.  329-332 ;  XXIX.  25-34).— Body  oblong, 
compressed,  ciliated  on  all  sides ;  mouth  lateral,  wdth  a  tongue-like  process ; 
no  ^isual  point.  The  cilia  are  disposed  in  longitudinal  series ;  those  near  the 
mouth  are  sometimes  longer  than  the  others,  and  are  alone  subservient  to 
locomotion,  except  in  two  doubtful  species.  In  P.  Chrysalis  the  long  oral  ciha 
are  remarkable.  The  digestive  cells,  Ehi^enberg  proceeds  to  say,  are  numerous, 
amounting  to  more  than  a  hundred,  and  are  arranged  in  a  berry-like  manner 
along  the  curved  alimentary  canal :  in  five  sj)ecies  they  have  been  demon- 
strated by  artificial  means,  in  a  sixth  by  its  usual  green  food.  The  ova  in 
two  species  are  seen  as  a  granular  mass.  In  all,  except  one  species,  male 
organs  are  visible.  The  curious  star-like  contractile  vesicles  in  the  larger 
species  are  highly  interesting,  when  physiologically  considered,  as  are  also  the 
little  black  bodies  seen  in  P.  Aiirelia.  In  four  species  complete  self-division, 
transverse  and  longitudinal,  has  been  observed  alternately.  This  genus  gives 
name  to  a  family  Parameciens  or  Paramecina  in  the  systems  of  Dujardin  and 
Perty. 

Stein  makes  the  uniformity  in  length  and  thickness  of  the  cilia  a  character- 
istic of  Paramecium,  which  distinguishes  it  both  from  Loxodes  and  Bursaria, 
which  have  larger  and  stronger  cilia  about  the  mouth  than  cover  the  rest  of 
the  body  (see  p.  285).  Ehrenberg's  statement  that  those  about  the  mouth 
are  longer  than  the  rest  requires  correction  ;  and  the  instance  (P.  Chrysalis) 
cited  indicates  only  that  this  species  is  not  a  Paramecium.  Other  par- 
ticulars requiring  revision  are,  that  Paramecia  have  numerous  stomachs  dis- 
posed as  ofi'sets  upon  a  curved  alimentary  tube ;  that  the  granular  mass  in 
the  interior  consists  of  ova.  The  male  organs  referred  to  are  the  nucleus  and 
contractile  vesicle  or  vesicles.  In  P.  Aurelia  and  P.  Bursaria  Lachmann 
states  that  the  anus  may  be  frequently  recognized,  in  the  form  of  a  small  pit 
on  the  surface  of  the  animals,  even  for  a  considerable  time  before  and  after 
an  excretion. 

In  our  remarks  on  Paistophrys  we  have  expressed  a  doubt  as  to  the  inde- 
pendent position  of  that  genus  apart  from  Paramecium. 


Paramecium  Aurelia  (M)  (xxv.  329- 
332). — Club-shaped,  cylindrical,  slightly 
attenuated  anteriorly.  An  oblique  longi- 
tudinal fold  borders  upon  the  very  much 
receding  mouth.  Ehrenberg  states  that 
he  has  seen  small  dark  crystalline  bodies 
abundant  in  the  frontal  region,  which, 
he  conceives,  are  indications  of  the  pre- 
sence of  nervous  matter,  as  such  cry- 
stalline bodies  often  accompany  it.  These 
creatures  appear  to  him  also  to  have  the 
sense  of  taste,  since  in  the  same  gi*oup 
some  individuals  prefer  one  kind  of  food 
and  others  another.  This  may  be  ob- 
sen-ed  by  mixing  blue  and  red  colours 
together,  when  some  will  feed  upon  the 
former,  others  upon  the  latter,  as  indi- 
cated by  the  colour  of  the  digestive 
cells :  in  some  the  cells  have  a  violet 
hue.  After  being  fed  witli  colour,  they 
may  be  dried  upon  glass  or  mica,  and 


thus  preserved.  According  to  the  hypo- 
thesis of  Ehrenberg,  the  rays  of  the  star- 
like vesicle  are  spermatic  ducts,  through 
which  the  fluid  is  forced  upon  the  ova 
in  the  vicinity  by  the  constantly  repeated 
acts  of  contraction  of  the  vesicle.  The 
ducts  are  long,  and  enter  the  ovarium  at 
many  points  (see  p.  312  et  seq.).  The 
expiilsion  of  ova  has  frequently  been  ob- 
served. The  colour  of  these  animalcules, 
when  bearing  ova,  is  white  by  reliected 
light,  and  yellow  by  transmitted  ;  hence 
the  names  ''  gold  and  silver  little  fishes," 
so  often  applied  to  them  by  Joblot  and 
others ;  those  devoid  of  ova  are  colour- 
less. The  cilia  are  best  seen  when  the 
water  is  coloured ;  there  are  from  20  to 
52  longitudinal  rows  along  each  side  of 
the  body,  according  to  Ehrenberg,  wlio 
says  that  in  some  rows  he  counted  from 
GO  to  70  cilia,  making  3(340  organs  of 


OF  THE  KOLPODEA. 


635 


locomotion,  and  that  each  cilium  is  placed 
upon  a  sort  of  little  knob  or  articulated 
base  (see  p.  285 ).  (Fig.  329,  a  dried  spe- 
cimen ;  fig.  330,  a  creature  feeding  upon 
indigo,  the  particles  of  which  around 
indicate  the  currents  produced  by  the 
cilia ;  fig.  332^  an  ideal  vieAv,  to  show 
the  structure  of  the  nutritive  organs  as 
stated  byEhrenberg;  fig.  331,  a  young 
specimen,  of  the  normal  shape. )  Abun- 
dant in  vegetable  infusions,  and  increases 
so  rapidly  in  stagnant  waters  that  some 
have  referred  their  marvellous  abmidance 
to  spontaneous  generation  from  elemen- 
tary primitive  matter.     1-120"  to  1-96". 

P.  caudatum. — Spindle-shaped ;  obtuse 
anteriorly,  attenuated  posteriorly.  Not 
in  infusions,  but  in  ponds,  amongst 
decayed  sedge-leaves  and  Confervae. 
1-120". 

P.  ClirysaJis  Q>L)  =  PIeuronema  eras- 
sum  (Duj.)  (xxvi.  23).  —  Oblong  and 
cylindrical,  equally  rounded  at  both 
ends ;  cilia  about  the  mouth  very  long. 
This  species,  like  P.  Aurelia,  is  often 
developed  in  such  vast  nmiads  that  the 
water  has  a  milky  hue,  the  masses  as- 
cending or  descending  in  the  fluid  :  this 
appearance  may  be  produced  by  slightly 
shaking  the  water.  In  infusions  and  in 
salt  water.     1-240"  to  1-190". 

If  the  imiform  length  of  the  cilia  be 
admitted  a  generic  character  of  Para- 
mecium, this  species,  which  has  several 
veiy  long  bristly  cilia  proceeding  fi'om 
the  oral  fissure,  must  be  excluded.  Both 
Dujardin  and  Perty  have  proposed  this, 
and  made  Paramecium  Clirysalis  the  re- 
presentative of  a  genus  styled  "  Pleuro- 
nema.^^ 

It  is  usually  fiUed  \vith  gi-eyish  mole- 
cules and  vesicles,  and  rarely  coloured 
with  chlorophyll.  Fission  longitudinal. 
The  long  fibres  from  the  lateral  oral 
fissures  are  from  two  to  twelve  in  num- 
ber, and,  though  frequently  shorter,  are 
at  times  equal  to  or  even  much  longer 
than  the  body,  and  serve  to  vary  its 
movements  by  their  activity. 

P.  KoIpoclaiKolpoda  Ren,  M. ;  K.  Cu- 
chUus,  D.). — Ovate,  slightly  compressed ; 
ends  obtiL-^e,  the  anterior  attenuated  and 
slightly  bent  like  a  hook.  Found  espe- 
cially in  infusions  of  Urtica  dioica  (the 
stinging  nettle).  Perty  is  disposed  to 
believe  this  form  to  be  an  earlier  stage 
of  P.  Aurelia.     1-240". 

P.  (?)  Sinaiticum.  —  Elliptical,  com- 
pressed, the  back  and  under  side  cari- 
nated  (keeled) ;  frontal  cilia  indistinct. 
Amongst  Confervae,  in  a  brook  on  Mount 
Sinai.     1-288". 


P.  (?)  oratum. — Ovate,  turgid;  an- 
teriorly attenuated  and  rounded.  In 
stagnant  river-water.     1-288". 

P.  compressum  (Bursaria  Lumhrici, 
Stein).  —  Elliptical  or  reniform,  com- 
pressed. An  oblique  ^Teath  of  long 
cilia  reaches  to  the  middle,  where  the 
mouth,  with  its  slight  tongue-like  pro- 
cess, is  situated.  Found  in  the  river- 
mussel  {Ml/a),  and  in  the  intestine  of 
the  earthworm  (Lambricus).  1-240"  to 
1-210". 

Dujardin  takes  this  species  as  the  type 
of  a  newly-formed  genus,  "  Phujiotoma,'''' 
characterized  especially  by  its  com- 
pressed lameUar  figure,  and  by  its  para- 
sitic habitat.  Its  cilia  are  described  as 
disposed  in  longitudinal  rows  over  the 
surface  (vide  ante,  p.  627). 

We  agree  with  Stein  that  there  is  no 
good  reason  for  framing  the  genus  Pla- 
giotoma,  as  Dujardin  has  done,  on  the 
characters  of  this  animalcule.  If  it  have 
no  mouth  it  should  take  its  place  among 
the  Opalince;  and  it  is  to  be  remarked 
that  though  Dujardin  clearly  saw  a  deep 
fold  or  fissure — a  feature  of  Opalince — he 
could  not  succeed  in  artificially  feeding 
the  animal  with  coloured  food.  At  all 
events,  it  has  certainly  no  right  to  a  place 
among  Paramecia,  since  the  crest  of 
longer  cilia  about  the  mouth-like  fossa 
refers  it  (supposing  it  to  have  a  mouth) 
to  the  Bursari(2. 

P.  Ifih'um  (CycUdiwn  3IiUum,  M.). — 
SmaU,  oblong,  trilateral ;  rounded  equally 
at  both  ends.  In  coloured  water  the 
body  is  seen  vibrating.     I-lloO". 

P.  Bursaria  =  Loxodes  Bursaria  (Ehr.) 
(xxrx.  25-34). — It  is  not  a  Loxodes,  since 
all  its  cilia  are  equal  and  similar,  Ehr- 
enberg  being  in  error  respecting  the  ex- 
istence of  a  larger  sort  in  the  infundi- 
bulum  leading  to  the  mouth. 

P.  versutam  Q<l\\)lQ-i:)=  Bursaria  ver- 
nalis  (?)  (Ehr. ). — Perty  revives  this  spe- 
cies ;  but  Lachmann  (A.  N.  H.  1857,  xix. 
215)  thinks  it  unnecessary  to  do  so,  "  as 
there  is  scarcely  any  certtiinty  in  the 
synonymy  previous  to  Ehrenberg;  and 
we  should  never  again  introduce  an  older 
specific  name  for  an  Infusorium  if  it  has 
a  name  given  to  it  by  Ehrenberg,  even 
when  it  is  not  improbable  he  may  have 
overlooked  an  older  name.'' 

b.  var.  Alpina  (Perty).  —  Smaller, 
plaited,  stouter  and  more  cylindrical 
than  P.  versa fum. 

P.  f/riseolum  (Perty).  —  Little  trans- 
parent, being  filled  with  gre;\'ish  mole- 
cules ;  border  very  delicate.  Nine  to  ten 
longitudinal  plaits  on  the  surface.  Move- 


636 


SYSTEMATIC  HISTOEY  OF  THE  IN-FUSOEIA. 


ment  sudden,  frequently  oscillating-. 
1-430." 

P.  aureoJum.  —  Transparent,  peacli- 
coloured  or  golden  yellow ;  plaits  strong. 
Movements  sluggish.     1-430". 

P.  leucas=Bursana  leucas?  (Elir.). — 
On  one  side  a  liorn-like  process,  and  on 
the  other  a  pair  of  eminences  project. 
Movements  slow. 

P.  stomioptycha  (E.).  —  Oblong,  ob- 
tusely ovate,  tm-gid ;  oral  aperture  large. 


reniform,  cilia  long;  body  marked  by 
circular  folds ;  lip  with  peculiar  appen- 
dages ;  vesicles  two,  stellate ;  nucleus 
elongated,  cylindrical.  Mouth  occupies 
the  anterior  third  of  the  body,  sur- 
mounted, however,  by  its  obtuse  frontal 
end;  cilia  dense,  in  longitudinal  rows; 
vacuoles  numerous ;  colour  yellowish- 
white  ;  nucleus  above  one-third  of  the 
entire  length,  which  varies  from  1-24'" 
to  1-15'". 


Genus  AMPHILEPTUS. — Tongue-like  process  and  eye-speck  absent ;  but 
the  body  is  furnished  with  a  proboscis  and  tail,  and  is  elongated  fusiform  or 
lanceolate.  Cilia  numerous,  disposed  in  longitudinal  series :  in  one  species 
cilia  are  not  visible ;  but  in  this  the  flexible  attenuated  extremities  of  the  body 
serve  their  office  as  locomotive  organs.  In  some  the  tail  (foot)  and  proboscis 
(brow)  are  rudimentary.  Numerous  vacuoles  filled  "with  food  may  be  fre- 
quently seen  ;  the  mouth  and  anus  are  usually  distinguishable.  A.  marga- 
ritifer  has  a  pale  rose-red  fluid.  A  contractile  vesicle  and  a  nucleus  are 
found ;  the  latter  is  globular  or  moniliform.  Self-di^ision  occurs  both 
transversely  and  longitudinally,  or  transversely  only. 

Speaking  of  Ehrenberg's  distribution  of  this  genus,  Dujardin  remarks — 
<'  This  author,  whilst  assuming  the  presence  of  proboscis  and  tail  (as  a  cha- 
racteristic), yet  refers  to  the  genus  animalcules  without  tail,  and  dilated  and 
rounded  posteriorly  ;  and  on  the  other  hand,  whilst  intent  on  seeking  a 
distinctive  character  for  his  different  families  in  the  position  of  the  anus, 
which  he  attributes  to  all  his  Enterodelous  Infusoria,  he  has  left  in  his  genus 
Trachel'ms  several  species  which  to  us  appear  to  belong  to  Amphileptus,  and 
has  himself  several  times  transferred  some  species  from  one  genus  to  the 
other."  The  Am-pliUeptus  Anser  is  taken  by  Dujardin  as  the  type  of  a  genus 
termed  Dlleptus,  and  A.  Meleayr'is  of  one  termed  Loxoj>7iyJhim.  Amphileptus  is 
the  name  of  a  genus  comprehended  by  Perty  in  his  family  Trachelina,  which 
appears  generally  equivalent  to  that  bearing  the  same  name  in  Ehrenberg's 
system ;  but  it  contains  besides,  TracheJhis  vorax.  Cohn  remaks  that  it  is 
imperfectly  distinguished  by  Ehrenberg  from  Tracliel'ms. 

The  Amphilepti  are  commonly  found,  in  the  Hmpid  water  of  marshes  or 
brooks,  among  aquatic  plants. 


Amphileptus  Anser  (  Vibrio  Anser  et 
Cygnus,  M.  =  Dileptus,  D.)  (xxiv.  312, 
3i3).  —  Turgid,  spindle-shaped  ;  pro- 
boscis obtuse,  same  leng-th  as  body ;  tail 
short  and  acute.  The  neck-like  pro- 
boscis is  in  reality  a  brow  or  upper  lip, 
the  mouth  being  at  the  base.  Ehrenberg 
thinks  he  has  seen  the  anal  opening  upon 
the  dorsal  surface,  near  the  tail.  The 
motion  of  the  body  is  slow,  but  that  of 
the  proboscis  more  active.  It  is  very 
often  coloured  green  with  chlorophyll, 
received  as  food.  Amongst  dead  sedge- 
leaves,  «&c.     1-120". 

A.  maryaritifer.  —  White,  slender, 
spindle-shaped  ;  proboscis  acute,  equals 
the  length  of  the  body  ;  tail  short.  The 
most  striking  features  are  the  swollen 
margin  of  the  mouth,  and  nccldace-like 


series  of  vesicles  disposed  along  the 
body.  It  feeds  upon  green  Monads,  like 
the  preceding  species  in  Ehrenberg's 
figm-es.  Cilia  are  not  sho\\Ti.  Amongst 
colonies  of  Vorticcllce,  &c.  1-72".  This 
species  is  the  counterpart  of  the  pre- 
ceding; and  the  distinction  found  by 
Ehrenberg  iu  the  necklace-like  vesicles 
has  no  value  as  such,  since  these  vary 
both  in  number  and  position  according 
to  the  abundance  of  food  and  other 
external  circumstances. 

A.  moniliyer. — Turgid,  ample,  white; 
proboscis  and  tail  short.  It  has  a 
necklace-like  collection  of  rose-coloiued 
vesicles.  Amongst  duck-weed.  1-96" 
to  1-72". 

A.  riri(Us. — Turgid,  spindle-shaped, 
green;    proboscis   and    tail    short    and 


OF  THE  KOLPODEA. 


637 


transparent.  Amongst  Lemnse.  1-120" 
to  1-96". 

A.  Fasciola  (  Vibrio  Anas,  Fasciola,  et 
intermedius,  Paramecium  Fasciola,  M.) 
(XXIV.  314-316  ;  xxix.  19,  20).— Wliite, 
depressed,  linear,  lanceolate,  convex 
above,  flat  beneath.  Wlien  viewed  from 
above,  from  ten  to  twelve  longitudinal 
rows  of  delicate  cilia  may  be  seen,  and 
in  the  middle  of  the  body  two  round 
nuclei,  and  behind  them  a  contractile 
vesicle  (xxiv.  314,  315,  316).  In  infu- 
sions, in  marshy  ponds,  &c.  Perty  states 
that  he  has  found  it  at  an  elevation  of 
5000  feet  on  the  Alps,  and  also  beneath 
the  ice.  Cohn  has  watched  its  power  of 
encysting  itself.  (Siebold's  Zeitschr.  1854, 
V.  p.  430).     1-720"  to  1-144". 

A.  3Ieleagris  {Kolpoda,  M. ;  Loxophyl- 
liim  3Mcagris,  D.). — Large,  compressed, 
membranous,  broadly  lanceolate  in 
shape,  with  the  crest  of  the  back  denti- 
culated. The  colour  of  this  interesting 
animalcide  is  white.  On  the  under  side 
there  is  a  more  or  less  distinct  row  of 
eight  to  ten  bright  colourless  spots. 
These  spots  are,  however,  in  no  constant 


number,  as  Ehrenberg  supposed ;  for  they 
are  nothing  more  than  coloured-food 
vacuoles,  which  sometimes  completely 
fill  the  animalcule.  With  Lemnae. 
1-72".     (See  notes  on  Nassula,  p.  625.) 

A.  longicollis  (Kolpoda  ocJirea,  Trichoda 
Felis,  M.). — Dilated  ;  turgid  posteriorly ; 
attenuated  and  elongated  anteriorly,  like 
a  sword.  Amongst  Lemnae.  1-120"  to 
1-96". 

A.  (?)  papillosas. — Depressed,  lanceo- 
late, fringed  with  papiUie  ;  tail  and  pro- 
boscis smooth.  Amongst  Confervae. 
1-600"  to  1-430". 

A.  Sphagni.  —  Depressed,  linear  or 
linear-lanceolate ;  proboscis  truncate 
and  keeled ;  tail  acute ;  fringed  with 
cilia  on  one  side  ;  green  corpuscles  oc- 
cupy the  centre,  leaving  the  extremities 
of  the  body  colourless  or  hyaline.  1-48" 
to  1-12".  Proboscis  is  one-fourth  the 
length  of  the  body.  Nucleus  ovate; 
cilia  disposed  spirally.  Vacuoles  some- 
times enclose  Bacillaria.  Ovules  (?) 
large.  Approaches  A.  Fasciola  in  general 
characters.     On  submerged  Spliagnum. 


Genus  UROLEPTUS  (XXY.  333).— Fm^nished  with  a  tail;  eye-speck, 
tongue-like  process,  and  proboscis  absent.  Locomotion  effected  by  the  cilia, 
which  cover  the  body,  and  are,  in  three  species,  evidently  disposed  in  rows. 
Numerous  vacuoles  and  a  mouth  have  been  demonstrated  by  coloured  food ; 
but  a  discharging  orifice  has  not  been  satisfactorily  determined.  Green- 
coloured  granules  are  e^ident  in  two  species,  but  no  nucleus  or  vesicle. 

This  genus  of  Ehrenberg  (says  M.  Dujardin),  judging  from  the  figures  of 
most  of  its  species,  should  be  in  part  united  with  O.vgtricJia.  Thus  Uroleptus 
Piscis  seems  identical  with  Oxytriclia  caudata  (Duj.)  ;  U.  Musculus  (Ehr.)  is, 
in  figure,  an  Oxytricha  ;  whilst  U.  (?)  Lamella  is  probably  a  Trachelius,  and  U. 
Filiim  is  rather  allied  to  Sj^irostomum  amhiguum.  If  these  views  be  correct, 
Uroleptus  should  be  erased  from  the  list  of  genera.  Three  species  counted  in 
this  genus  by  Ehrenberg  are  rejected  from  it  by  Perty,  and  allied  with  Oxy- 
tricha, — \\z.  U.  Musculus,  U.  Piscis,  and  U.  Lamella. 


UnoLEPTUS  Piscis  (Trichoda  Piscis, 
M.). — Green  ;  in  figure  like  an  elongated 
top,  gradually  attenuated  posteriorly, 
forming  a  thick  tail,  covered  with  cilia, 
those  at  the  mouth  largest.  Found,  in 
February  and  March,  amongst  the 
floccose  bro-WTi  coat  upon  dead  sedge- 
leaves,  along  with  Chlamydomonas  and 
Cryptomoncis.  Hampstead  ponds.  1-288" 
to  1-44". 

Perty  doubts  if  there  is  any  real  di- 
stinction between  this  animalcule  and 
the  Oxytricha  caudata  (Ehr.). 

U.  Musculus  {Trichoda  Musculus,  M.) 
(xxY.  333).— ^^Tiite,  cylindrical,  pear- 
shaped,  thickened  posteriorly,  where  it 
abruptly    terminates    in    a  "^tail.      The 


movement  rolling.  It  is  inactive  and 
rigid.     With  Oscillator  ice.     1-220". 

L^.  Hosjjes.  —  Greenish,  ovate-oblong 
and  turbinate  in  shape ;  obliquely  trun- 
cated and  exca^'ated  anteriorly  {  poste- 
riorly terminated  by  a  styliform  acute 
tail.     In  frog-  and  snail-spa^Nii.    1-240". 

U.  (?)  Lamella.  —  Transparent,  linear- 
lanceolate,  depressed,  flat,  very  thin.  In 
infusions.     1-220". 

U.  Filum  {Enchelys  caudata,  M.).  — 
White,  filiform,  cylindrical ;  rounded 
anteriorly ;  attenuated  posteriorly,  form- 
ing a  straight  long  tail.  It  is  considered 
a  Spirostomum  by  Dujardin  and  Perty 
{vide  ante,  p.  623).  In  stagnant  spring- 
water,  kc.     1-48". 


638 


SYSTEMATIC  HISTORY  OF  THE  r^FUSOHIA. 


Genus  OPHRYOGLENA  (XXY.  334,  335).— Ovoid,  ciliated,  with  an  eye- 
speck  anteriorly.  Locomotion  effected  by  the  numerous  regular  longitudinal 
rows  of  cilia.  Some  of  the  numerous  digestive  vacuoles  are  often  filled  with 
Naviculce.  The'  mouth  is  situated  in  a  fossa  beneath  the  brow  on  one  side  ; 
and  the  anal  orifice  lies  upon  the  dorsal  surface,  at  the  base  of  the  little  tail. 
A  large  central  nucleus  and  one  or  more  contractile  vesicles  are  found ;  trans- 
verse and  longitudinal  self-division  have  been  observed.  A  large  red  or  black 
stigma  is  always  present  on  the  frontal  region.  These  Infusoria  are  found  in 
stagnant  fresh  water,  but  not  in  infusions. 

As  Dujardin  rightly  remarks,  this  genus  differs  from  Koljpoda  only  by 
having  a  stigma  or  eye-speck ;  however,  he  prefers  to  place  it  among  Bur- 
sarina,  because  the  mouth  is  situated  at  the  extremity  of  a  row  of  cilia.  In 
this  transposition  of  Ojpliryoglena,  Perty  does  not  agree,  seeing  that  it  has  a 
narrow  mouth,  and  the  closest  affinity  with  Panophrys,  with  which,  therefore, 
he  replaces  it,  along  with  Paramecium,  &c.,  in  the  family  Paramecina.  We 
are  disposed  to  question  its  claim  to  a  generic  position ;  for  the  coloured  speck 
is  worthless  as  a  distinctive  character. 


Ophhyoglena  atra  (Letccopkra  Ma- 
milla,  M.). — Blackish,  ovoid,  compressed, 
acute  posteriorly.  A  black  stigma  is 
situated  anterioriy  near  the  dorsal  mar- 
gin. The  mouth  is  at  the  bottom  of  a 
funnel-shaped  cavity,  commencing  im- 
mediately beneath  the  brow  ;  within  this 
cavity  Ehrenberg  thinks  he  has  lately 
seen  an  oval  bright  gland.  The  colour- 
less cilia  appear  like  silver  fringe  on  the 
dusky  animalcule,  especiallv  those  in 
front.     In  turf-hollows.     1-180". 

O.  acuminata  (xxv.334,335). — Brown, 
ovate,  and  compressed ;  tail  short  and 
acute  ;  stigma  red.  The  brow  projects 
beyond  the  mouth  about  the  length  of 
the  bod}',  or,  in  other  words,  is  situated 
about  the  middle.  In  turf-hollows. 
1-180". 

O.  Jiavicans. — YelloAv,  turgid,  o\'ate, 
attenuated  and  rounded  posteriorly; 
stigma  red,  irregular  in  shape  ;  the  cilia 
near  the  mouth  longer  than  in  the  pre- 
ceding species ;  Ehrenberg  counted  from 
twelve  to  sixteen  rows  at  one  view.  In 
turf-hollows.     1-144". 

Nothing  like  a  lens  can  be  seen  ^^thin 
the  eye-speck ;  but  close  to  it  there  is  an 
hour-glass-shaped  body,  transparent  and 
apparently  structureless.  Its  position 
seems  fixed,  but  it  may  be  detached  by 
diffluence  of  the  animalcule,when  it  swells 
up  in  the  surrounding  water  and  often  ex- 
hibits a  central  cavity.  Its  presence  is  not 


necessarily  associated  with  the  colo^ued 
stigma :  in  Ophryogloia  atra  it  is  ab- 
sent ;  and  whilst  Biirsaria  possesses  this 
organ,  it  has  no  coloured  speck.  In 
other  Infusoria  having  stigmata,  such  as 
Euglenaea,Peridini£ea,  &c.,  no  such  organ 
is  discoverable  in  connexion  with  them 
(Miiller's  Archiv,  1856,  p.  21).  Stein 
advances,  as  a  distinctive  character  be- 
tween Oph.Jlavicans  and  Bursariajlava, 
the  difference  subsisting  in  respect  of  the 
nucleolus. 

O.  griseovirens  (Perty).  —  Elliptical, 
with  more  or  less  unequal  sides  ;  usually 
more  pointed  behind,  and  romided  in 
front,  where  a  red  or  dark  pigment-speck 
is  visible.  Hyaline,  and  when  strongly 
magnified  reticular ;  but  frequently  con- 
tains grey  or  gTeen,  and  in  rare  cases 
brown  molecules.  The  marginal  cilia 
very  distinct.  Oral  fossa  in  anterior 
half.  Movements  quick  and  revolving. 
1-300"  to  1-180".'    In  ponds,  Bern. 

O.  Panophrys  (Perty).  —  Large,  oval 
when  seen  on  the  wider  side ;  pointed 
end  posterior ;  colour  greyish  yellow ; 
without  pigment-speck.  When  seen  on 
the  narrow  side,  the  marginal  cilia  appear 
in  concentric  curved  lines,  whilst  on 
the  broad  side  the  cilia  are  close  together 
and  apparently  irregular.  Movements 
slow.  Usually  swims  on  one  of  its  wider 
sides,  and  but  seldom  revolves.  Mouth 
wide.     1-144".     Uncommon. 


Genus  DILEPTUS  (Duj.)  (XXYI.  26).— This  genus  belongs  to  the  family 
''  Trichodina  "  {ante,  p.  608),  and  is  thus  defined : — Animal  with  a  fusiform 
body,  much  elongated  anteriorly,  like  a  long  neck,  with  a  mouth  seated  at  the 
base  of  the  prolongation;  \dbratile  cilia  cover  the  surface,  and  are  of  larger 
size  in  front  and  near  the  mouth. 

Ehrenberg  has  arranged  Dileptus  with  the  Paramecina,  although,  unlike 


OF  THE  OXYTEI CHINA.  639 

the  latter,  destitute  of  a  contractile  reticulated  integument.  The  type  of  this 
genus  is  the  AmpTiileptus  Anser  of  Ehrenberg  ;  and  the  A.  margaritifer  (Ehr.) 
is  also  referable  to  it. 


DiLEPTUs  Folium  (Duj.)  (xxvi.  26). 
— Very  flexible  ;  lanceolate,  contracted 
in  front,  -vsdth  nodidar  reticulated  and 
irregular   stripes,   like    the   veins   of    a 


leaf.     In  river- water.    1-175"  to  1-130", 
Perty  remarks  that  this  organism  can- 
not be  a  species  of  Dileptus. 


Genus  LOXOPHYLLUM  (Duj.)  (XXVI.  32).— Very  depressed,  lameUar, 
oblique,  very  flexible ;  sinuous  or  undulated  along  the  borders  ;  mouth  lateral ; 
cilia  in  wide  parallel  rows. 

Ehi'enberg  has  comprehended  Loxopliyllum  with  Amphileptus.  Perty 
makes  the  separation. 


LoxoPHYLLUM  3Ieleagris,  the  type  of 
the  crQ\\vis=^  Amphileptits 3Ieleagris(Fhr.^. 

The  Trachelius  Melcagris  (Ehr.)  pro- 
bably   represents    also    another    Loxo- 


phyllum,  as  weU  as  the  Kolpoda  ochrea 
of  Miiller,  which  Ehrenberg  states  to 
agree  with  his  Amphileptus  longicoUis. 


Genus  PLEURONEMA  (Duj.  and  Perty)  (XXVI.  23),  represented  by 
the  Paramecium  Chrysalis  (Ehr.),  is  thus  defined  by  Dujardin  : — ''Body  oval, 
oblong,  depressed ;  having  one  large  lateral  orifice,  from  which  a  tuft  of  long, 
floating  and  contractile  filaments  issues."  It  has  nothing  in  common  with 
Paramecium,  he  adds,  besides  its  oblong  figure ;  whilst  the  bundle  of  long 
filaments  has  no  analogy,  except  in  the  genus  Alyscum.  However,  he  places 
it  in  his  family  Parameciens,  whilst  Perty  introduces  it  as  the  sole  represen- 
tative of  a  family  "  Aphthonia,"  characterized  as  having,  besides  locomotive 
cilia,  other  longer  ones  or  filaments. 


Pleuronema  crassum  =  Paramecium 
Chrysalis  (Ehr.).  —  Ovoid,  much  elon- 
gated, rather  depressed;  with  obtuse 
ends ;  finely  striated.     Lateral  oriflce  at 


the  anterior  fourth  of  the  body,  with 
long  filaments,  some  proceeding  from 
the  border,  others  from  the  posterior  ex- 
tremitv.    1-120".    In  the  Mediterranean. 


Genus  OTOSTOMA  (Carter,  ^.A^^.  1856,  xvii.  117)  (XXVIII.  24^26).— 
Body  ovoid,  of  a  light  brown  colour,  covered  with  longitudinal  lines  of  cilia. 
Mouth  ear- shaped,  in  a  depression  situated  about  the  junction  of  the  anterior 
with  the  middle  third  of  the  infusorium ;  buccal  cavity  broad,  short,  curved 
do^vnwards,  and  a  little  upon  itself  outwards,  plicated  longitudinally  in 
parallel  lines.  Anus  terminal ;  gland  or  nucleus  long,  fusiform,  situated 
between  the  buccal  cavity  and  the  contracting  vesicles,  which  are  double 
and  connected  with  a  set  of  vessels  something  like  those  of  Parameciiun 
Aurelia. 

"  It  is,"  adds  Mr.  Carter,  "  a  Paramecium  closely  allied  to  NassuJa,  and, 
from  the  likeness  of  the  oral  orifice  to  the  human  ear,  I  propose  for  it  the 
name  of  '  Otosfoma.^ "  Its  cysts  have  been  discovered  on  Nitella,  and  give 
exit  to  monadiform  beings  approaching  the  parent  Otostoma  in  form. 

FAMILY  XL— OXYTBICIIIXA. 

(XXV.  336-344;    XXVIII.  43-47.) 

Possess  two  separate  alimentary  orifices,  neither  of  them  situated  at  the 
extremities,  and  are  not  encased  by  a  de'nse  integument  (lorica).  Their  loco- 
motive organs  are  various,  consisting  of  set®,  vibratile  cilia,  and  non-vibratile 
styles  or  uncini,  variously  situated,  and  render  the  creatures  active.  (Poly- 
gastric  cells,  disposed  upon  an  alimentaiy  tube,  were  represented  by  Ehren- 


640 


SYSTEMATIC  KTSTOEY  OF  THE  IT^FUSOEIA. 


berg,  excejDt  in  CeratkUum.)  A  curTcd  line  of  strong  cilia  leads  towards  the 
mouth,  which  is  situated  about  the  median  line  at  the  posterior  third  of  the 
body,  and  opens  into  a  ciliated  oesophagus.  The  anus  is  behind  the  mouth, 
on  the  same  ventral  surface,  near  its  margin.  Complete  transverse  and  longi- 
tudinal self-division  is  observed.  The  process  of  encysting  may  be  presumed 
general ;  in  Urostyla  Cohn  has  seen  the  ulterior  development  of  a  cihated 
embrvo. 


CiHa  and  ^etx,  no  styles  or  uncini 


Brow  without  horns  Oxytricha. 

Brow  with  horns    Ceratidium. 

( With  uncini,  no  styles   Kerona. 


Styles,  or  uncini,  or  both. \  With  styles,  no  uncini  Urostyla. 

\  With  styles  and  uncini Stylonycliia. 

This  family  is  generally  similar  to  the  Keronina  of  Dujardin, — a  family 
of  animalcules,  according  to  this  observer,  much  lower  in  the  scale  than 
many  in  the  families  previously  described,  such  as  Koljpoda,  Paramecium, 
Coleps,  &c. 

"  Processes  in  the  form  of  styles  or  hooks  characterize  both  the  '  Keroniens ' 
and  the  'Ploesconiens ; '  but  the  latter  have  a  shield  (lorica),  whilst  the  former 
are  soft  and  have  no  sign  of  an  integument.  Of  the  '  Keroniens '  the  O.vy- 
tricha  have  neither  horns  nor  hooks,  but  only  cirrhi  or  straight  processes, 
apparently  rigid ;  another  genus,  *  Halteria,'  has  large  cirrhi  like  the  pre- 
ceding, but  differs  considerably  in  its  mode  of  life  and  its  movements. 

"  The  Urostyla  of  Ehrenberg,  with  styles  only,  and  no  hooks  (uncini),  we 
unite  with  Oxijtriclia;  and  his  Stylonycliia,  provided  with  both  styles  and 
hooks,  with  Kerona ;  another  genus  described  imder  the  name  of  CeratkUum, 
horned  anteriorly,  but  wanting  both  styles  and  hooks,  seems  to  be  only  altered 
or  mutilated  Keronce.  On  the  other  hand,  Halterkt  appears  to  be  included 
by  Ehrenberg  among  true  Urceolaria,  in  his  genus  Trkliodina,  although  it 
possesses  none  of  the  characters.  The  Keroniens  are  found  in  stagnant  water, 
fresh  and  salt."  Perty  has  established  a  family  Ox\'trichina,  which,  besides 
containing  two  new  genera,  styled  Mitophora  and  Stichotricha,  excludes  Cera- 
tidium and  Stylonycliia,  referring  the  species  of  the  latter  genus  to  Kerona. 
After  these  exclusions  and  additions,  Perty's  Oxytrichina  include  Oxytricha, 
Urostyla,  Kerona,  Mitophora,  and  Sticliotriclia. 

Genus  OXYTRICHA  (XXV.  336,  337;  XXIX.  21-24).— Styles,  uncmi, 
and  horns  wanting.  The  body  is  soft,  flexible,  oval  or  oblong,  more  or  less 
flattened,  and  pro\ided  with  cilia  and  setae.  Their  movements  are  forwards 
and  backwards,  often  by  imi^ulse, — creeping,  swimming,  and  climbing.  In 
all  the  species,  digestive  vacuoles  are  evident ;  in  five,  (ova-like)  granules  ;  in 
four,  a  nucleus ;  and  in  five,  round  contractile  vesicles.  Transverse  and  longi- 
tudinal division  is  observed  in  0.  Lepus  and  0.  Pellionella  ;  longitudinal  only 
in  0.  Cicada,  and  perhaps  in  0.  Pidlaster.  The  Triclioda  Nasamomum  and 
T.^tliiopica  (Ehr.)  and  Urostyla  belong,  in  Dujardin's  ojoinion,  to  0.vytri<:lia, 
and  Oxytricha  Cicada  (Eh]\)  to  the  Phesconiens. 

WTiilst  admitting  a  genus  Oxytricha,  Perty  makes  two  divisions  of  it,  the 
one  corresponding  generally  to  Uroleptus  (Ehr.),  and  the  second  to  Oxytricha 
(Ehr.).  The  differential  characters  given  are: — a.  Elongated  posteriorly, 
embracing  most  Urolepti  (Ehr.)  ;  h.  Rounded  posteriorly,  equivalent  to  Oxy- 
tricha (Ehr.).  Under  the  first  division  the  species  enumerated  are  0.  caudata, 
0.   Piscis,    0.   Mnscidus,    0.   amhif/na,   and  0.   Lamella  :  under  the  second. 


OF  THE  OXYTRICHIXA. 


641 


0.  proteusa,  0.  PeUionella,  0.  gihha,  0.  GaUina,  0.  PuUaster,  0.  Lepiis  ?,  0. 
pJatystoma,  0.  decumana,  and  0.  fusca. 


OxYTEiCHA  7'ubra  (Trichoda  Piscis  et 
T.  patens,  M.).  — Of  a  brick-red  colour ; 
linear  in  shape,  plane  on  the  imder  side, 
and  equally  rounded  at  the  ends ;  pos- 
terior end  provided  with  sette.  In  sea- 
water.     1-140". 

0.  PeUionella  (TricJioda  PeUionella,  M.) 
(xxix.  21-24). — White,  smooth ;  slightly 
depressed,  equally  rounded  at  both  ends, 
often  broader  in  the  middle;  head  not 
separate  ;  mouth  ciliated  ;  tail  provided 
with  setae.  Each  animalcide  has  two 
oval  nuclei,  and  between  them  a  single 
round  vesicle.  When  self-division  com- 
mences, fom*  glands  are  developed ;  and 
then  the  vesicle  divides.  Ehrenberg 
counted  ten  cilia  anteriorly,  and  four  or 
five  setse  posteriorly :  the  anal  outlet  is 
at  the  base  of  the  setse.  In  infusions, 
and  throughout  Switzerland  in  swampy 
ponds  along  the  snow-line  of  the  Alps 
(Pert^').  Auerbach  has  seen  it  encyst 
itself '(Siebold's  Zeitschr.  1854,  v.  p.  430). 
1-720"  to  1-280". 

Cienkowsky  surmises  this  species,  O. 
gihha,  Stylonychia  pustulata,  and  S.  lan- 
ceolata  to  be  one  and  the  same  animal- 
cule in  different  stages  of  growth  and 
under  different  circumstances  in  respect 
of  food,  &c.  This  notion  is  favom-ed,  he 
says,  by  the  fact  that  the  animalcule 
wLich  escapes  from  an  encysted  S.  lan- 
ceolafa  is  exactly  like  S.  jJashdafa. 

0.  caudata.  —  Smooth,  white  ;  linear- 
lanceolate  in  shape,  rounded  anteriorly, 
attenuated  posteriorly  in  the  form  of  a 
tail,  which  is  provided  with  setae.  Mouth 
evident.  In  fresh  and  sea-water.  1-576" 
to  1-84".  (See  ^ty-lo^y chix  imstidata.) 

O.platy stoma  =■  O.  eiiry stoma. — White, 


ovato-oblong,  under  side  flat,  yvith.  mar- 
ginal setae  ;  mouth  large  and  ciliated.  It 
swims  with  a  revolving  and  vacillating 
motion,  and  often  upon  the  back.  It 
creeps  upon  water-plants,  in  standing 
bog- water.     1-240". 

O.  yihha  (^Trichoda  gihha  et  foeta,  M.) 
(xxv.'  336,  337).  —  White,  lanceolate, 
ends  obtuse,  middle  enlarged,  under  side 
flat,  and  furnished  with  two  series  of 
setae,  and  a  large  roimd  moTith.  This 
species  resembles  O.  PeUionella,  but  is 
distinguished  by  its  setae,  the  two  or 
three  contractile  vesicles,  and  the  nu- 
cleus. This  creature  is  active,  and  runs 
nimbly  along  aquatic  plants  in  fresh  and 
brackish  water.  (Fig.  336  an  under 
view,  fig.  337  a  side  view.)  1-240".  It 
is  not  equivalent  to  the  O.  gibha  (Duj.). 

0.  PuUaster  (Trichoda  PuUaster,  Kerona 
PuUaster,  M.).  —  Whitish,  lanceolate, 
ends  obtuse,  ventral  surface  naked  at  the 
middle :  the  head,  indicated  by  a  con- 
striction, is  hairy,  like  the  tail.  The 
mouth  narrow.  In  water-butts,  streams, 
and  infusions.  1-430".  This  form  and 
O.  Lepus  Perty  believes  to  be  mere  va- 
rieties of  O.  PeUionella. 

O.  Cicada  {Trichoda  Cicada,  M.).  — 
Ovate,  or  almost  hemispherical,  back 
furrowed  and  notched,  under  sm-face 
fiat.  Upon  the  surface  of  stagnant 
water.     1-1440"  to  1-860". 

0.  Lepus. — Whitish,  elliptical,  smooth, 
flat ;  ciliated  anteriorly ;  provided  with 
setae  posteriorly ;  the  mouth  and  dis- 
charging orifices  not  distinct;  and  the 
nucleus  imobserved.  In  standing  water. 
1-540"  to  1-96", 


The  following  additional  species  are  given  by  Dujardin  :- 


O.  incrassata. — Ovoid,  long,  colourless, 
fringed  posteriorly  with  rigid  setae.  Not 
so  long  as  0.  PeUionella,  and,  unlike  it, 
marine.    In  the  Mediten-anean.    1-350". 

0.  Lingua.  —  Diaphanous,  flattened, 
flexible,  elongated,  rounded  at  each  end ; 
without  setae  or  apparent  cilia  poste- 
riorly; gi-anules  of  smface  in  nearly 
regulai-  rows.  In  ditch-water  with  Con- 
fer vae.     1-212". 


0.  amhigua. — Colourless,  oval,  oblong- 
depressed  in  the  middle,  concave  on  one 
side  ;  margin  tumid ;  ■v\dth  very  strong 
locomotive  cilia  on  the  concave  sm'face, 
and  with  rigid  setae  behind.  In  sea- 
water.     1-350". 

O.  radians. — Discoid,  red,  surrounded 
by  long  radiating  setae.  In  salt  or  brack- 
ish water.     1-520". 


Perty  brings  forward  the  following  as  new  species,  belonging  to  true  Oxy~ 
triclia,  characterized  by  severally  having  a  round  posterior  extremity : — 

0.  proteusa  (Perty). — Very  long,  and  I  longer  than    broad.      It   is    sometimes 
subcylindrical ;    nine    to   twelve    times  |  actually  four-sided,  with  wdde  upper  and 

2t 


642 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


under  surfaces.  Mouth  a  rather  curved 
and  ciliated  fissure.  Cilia  very  fine, 
those  of  the  upper  surface  the  more  di- 
stinct, although  faint.  Small  specimens 
are  colourless  and  transparent ;  but  larger 
ones  have  dark  grey  molecules  or  chloro- 
phyll within.  Movements  tolerably  ac- 
tive. Pei-tj^  once  thought  this  species 
and  Traclielius strictus  (Duj.)  to  be  young 
individuals  of  Spirostomum,  but  he  subse- 
quently found  examples  1-84"  in  length. 

O.  galUna  (Perty)  =  Trichoda  gallina 
(?)  (Miiller). — Anterior  portion  hyaline, 
flat,  with  laT'ge  cilia;  molecules  grey. 
Only  once  seen. 

O.  decmnana  (Perty). — Outline  rather 
irregular;  rather  smaller  in  front  than 


behind,  broadest  in  the  middle;  ends 
rounded ;  upper  suiface  slightly  convex, 
lower  flat.  Mouth  wide.  It  differs  in 
size  from  O.  platy stoma  and  in  its  out- 
line both  fi'om  that  species  and  O.  fiisca. 
In  length  it  equals  TJrostyla  grandis,  but 
is  much  broader.  Bern,  in  ponds.  1-96". 
O.  fiisca. — Narrow,  elliptical,  upper 
sm-face  convex,  lower  concave.  Oral 
orifice  wide.  Colour  usually  yello^dsh 
or  blackish-browTi.  Lives  in  stagnant 
and  mouldy  water.  Cilia  in  fi'ont  and 
about  the  mouth  strongest ;  but  no  uncini 
occm-  there.  TJrostyla  grandis  differs 
fi'om  it  by  the  uncini  on  its  border. 
1-160"  to  1-84". 


Genus  CEEATIDIUM  (XXV.  338,  339).— Ciliated,  with  horns  on  the 
frontal  region,  but  no  styles  or  uncini.  Little  of  their  organization  is  known ; 
and  therefore  their  systematic  position  is  uncertain.  A  power  of  not  less 
than  350  diameters  is  required  to  examine  these  creatures. 


Ceeatidium  cuneatum  (xxv.  338, 
339). — Body  triangular ;  front  trimcated, 
as  also  the  two  horns ;  upper  side  smooth. 
Ehrenberg  found  this  whitish  animalcule 
in  1820,  amongst  Confervae,  but  had  not 


lately  seen  it.  Dujardin  believes  it  to 
have  been  a  mutilated  Oxytricha.  It 
vibrates,  runs,  and  climbs  quickly. 
1-430". 


Genus  KEHOISTA  (XXY.  340,  341).— Cilia  and  uncini  present,  but  no 
styles.  Body  soft,  flexible,  oval,  flattened,  and  ciliated,  with  claws  (uncini), 
and  perhaps  setae,  on  the  under  siufaee.  Yacuoles  numerous ;  the  oral  (and 
probably  the  anal)  aperture  is  upon  the  ventral  surface.  One  or  more  con- 
tractile vesicles  and  a  nucleus  have  been  seen;  but  self-division  has  not 
been  observed. 

This  genus,  instituted  by  Miiller,  was  at  first  adopted  by  Ehrenberg  with 
little  modification ;  but  subsequently  he  transposed  almost  all  its  species  to 
his  genus  Stylonychia,  on  account  of  their  possessing  styles  as  well  as  uncini. 
This  can  scarcely  be  considered  a  sufiiicient  reason  for  the  construction  of  a 
new  genus;  and  accordingly  Dujardin  rejects  Sfylonychia,  and  thus  restores 
the  genus  Kerona  nearly  to  its  original  importance.  As  already  noted,  he 
likewise  adopts  Kerona  as  the  representative  of  his  family  Keronina.  Perty 
coincides  with  the  French  naturalist,  and  rejects  both  Ceratidium  and  Stylo- 
nychia, treating  the  species  of  the  latter  as  examples  of  Kerona.  He  remarks 
that  Ehrenberg  has  very  needlessly  changed  the  name  Kerona,  given  by  MiiUer, 
for  that  of  Stylonychia. 

The  Keronce,  thus  understood,  differ  from  Oxytricha  only  ii^  the  form  of 
their  ciiThi  or  processes,  the  base  of  which  is  commonly  dilated  in  the  form 
of  a  transparent  globe,  and  moveable  withal.  Moreover  they  are  equally 
voracious,  are  abundant  in  stagnant  water  and  infusions,  and  capable  of 
being  much  varied  in  form. 


Kerona  polyporwn.  —  Whitish,  de- 
pressed, elliptical,  and  renifonn ;  a  series 
of  cilia  suiTounds  the  frontal  region,  ex- 
tended from  beneath  the  mouth.  Ehren- 
berg counted  above  forty  vacuoles,  many 
of  them    filled   ^nXh.    brownish    (half- 


digested  green)  Monads,  (xxv.  340  is 
a  back  \dew,  and  341  a  side  view, 
climbing.)  Parasitic  on  Hydra  vulgaris 
(Microsco^nc  Cabinet,  p.  7).  Animals 
infested  with  them  die.  1-144". 
This  species  is  thet^-pe  of  a  genus  named 


OF  THE  OXYTRICHINA. 


643 


Alastor  in  Perty's  system,  detached  from 
other  Ciliata  by  reason  of  its  parasitic 
habits,  and  placed  vnihPlagiotoma  (Duj.) 
and  Opalina  in  a  family  named  Cobalina. 

K.  pustulata  (J)\x\.)  =  StyIoHychia  pus- 
tidata. 

K.  Histrio  (T>\i].)  =  St.  Histrio. 

K.  Mytilm  {Y)uy)  =  St.  Mijtilus. 

K.  Silurus  (Diij.)  =  '^i^.  Silurus. 

K.  lanceolata  =  St.  lanceolata. 


K.  Calvitium  (Miill.),  K.  Jimhriata 
(Miill.),  and  Triehoda  foveata  and  Tr. 
Camelus  (MiilL),  are  probably,  according- 
to  Dujardin  and  Perty,  mere' varieties  of 
K.  pustulata. 

K.  Pullaster  (Mull.)  is  cited  by  Ehren- 
berg  as  =  Oxytricha  Pullaster,  but,  as 
Dujardin  thinks,  is  only  an  imperfectly- 
examined  or  a  deformed  specimen  of 
St.  pustulata. 


Genus  UROSTYLA  (XXV.  342).— CiHa  and  styles  present,  uncini  want- 
ing ;  the  cilia  are  thickly  disposed  in  numerous  rows,  and  are  longer  near 
the  mouth.  On  the  ventral  surface,  at  the  posterior  end,  is  a  small  cleft, 
provided  with  non-vibratile  setae.  Internally  are  numerous  vacuoles,  which 
may  be  filled  with  particles  of  colour ;  a  nucleus,  a  contractile  vesicle,  and 
Transverse  self-division  has  been  observed. 


delicate  granules. 

Urostyla  gmndis  (xxv.  342).  — 
White,  semicylindrical,  rounded  at  the 
ends ;  slightly  enlarged  anteriorly,  hence 
club-shaped ;  styles  short ;  mouth  large, 
one-fom-th  to  one-third  the  length  of  the 
body.  It  has  long  cilia  on  both  sides ;  the 
discharging  orifice  has  from  five  to  eight 
little  styles  on  the  left  side  only ;  sto- 
mach-juice colourless.  The  young  ani- 
malcules are  fiatter  than  the  old  ones. 
(xxv.  342,  an  imder  view  with  glands, 
vesicle,  and  the  cells  filled  with  Bacil- 
laria    and    colom-ed    matter.     Currents 


produced  by  the  vibration  of  the  cilia 
about  the  mouth  are  also  indicated  in 
the  drawing.)  On  slimy  dead  sedge- 
leaves.  1-144"  to  1-96".  Perty  doubts 
the  independent  specific  character  of  this 
form,  and  would  rather  consider  it  a 
variety  of  Oxytricha  fusca,  or  more  pro- 
bably of  Oo  platystoma  in  a  further  deve- 
loped state ;  for  Ehrenberg  admits  that 
the  imcini  at  the  posterior  extremity  are 
small ;  and  if  so,  they  can  scarcely  be 
characteristic. 


Genus  STYLONYCHIA  (XXV.  343,  344  ;  XXVIII.  10,  74-76 ;  XXIX. 
18). — Ciliated,  and  armed  with  styles  and  uncini  variously  disposed. 

In  one  species  Ehrenberg  thought  he  had  traced  the  course  of  the  alimen- 
tary canal  with  its  numerous  digestive  cells  ;  in  the  others,  he  found,  coloured 
food  was  received.  Transverse  and  longitudinal  self-di\ision  occurs  in  two 
species;  transverse  only  in  a  third.  In  S.  pustulata,  the  formation  of 
gemmae  is  said  to  occur.  Perty  remarks  that  Ehrenberg,  without  any  suffi- 
cient reason,  has  transferred  many  of  the  Keronce  of  Miiller  to  fStylonychia. 
The  granules  and  molecules  are  numerous,  and  often  in  heaps ;  one  or  two 
nuclei  and  a  contractile  vesicle  are  generally  visible. 


STYi.ois!Ycm.x  3Iytilus  (Triehoda  3Iy- 
tilus,  Kerona  Mytilus,  M.  and  Perty) 
(xxviii.  10).  —  White,  flat,  oblong, 
slightly  constricted  in  the  middle,  ob- 
liquely dilated  anteriorly  in  the  form  of 
a  mussel.  The  extremities  are  so  trans- 
parent that  they  give  it  the  appearance 
of  being  covered  with  a  shield ;  but  they 
are  soft,  flexible,  and  ciliated.  Dujardin 
observes  that  the  integumentary  appen- 
dages are  very  long,  consisting  of  a  row 
of  strong  cilia  in  front,  a  series  of  uncini 
and  numerous  styles  behind.  The  line 
of  cilia  leading  to  the  mouth  does  not 
reach  the  centre  of  the  body.  Its  extre- 
naities  are  so  thin  and  flexible  that  they 
yield  before  obstacles  in  their  move- 
ments, like   the   Ploesconia  Patella.     It 


differs  little  from  S.  (K.)  pusttdafa,  ex- 
cept in  size  and  the  strength  of  its  super- 
ficial processes.  The  middle  of  the  body 
is  sometimes  filled  with  delicate  white 
granules.  Often,  however,  as  Perty  men- 
tions, the  animalcule  is  coloured  green 
with  chlorophyll  received  in  its  food. 
This  animalcule  generally  has  a  peculiar, 
thrusting,  forward-and-back  movement, 
but  can  climb,  run,  and  swim  nimbly, 
usually  with  the  back  undennost.  Ehr- 
enberg foimd  that  a  single  animalcule 
lived  nine  days :  during  the  first  twenty- 
fom-  hours  it  was  developed  by  transverse 
self-division  into  three  animals;  these 
in  twenty-four  hom's  more  formed  two 
each,  in  the  same  manner;  so  that,  by 
self-division  only  (without  ova),  these 
2t2 


644 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


animalcules  increase  three-  or  fourfold 
in  twenty-four  liours,  and  may  thus  pro- 
duce a  million  from  a  single  animalcule 
in  ten  days.  An  abundant  supply  of  food 
favours  self-division.  In  infusions  and 
amongst  Oscillatorics,  &c.,  in  stagnant 
marsh-waler.    1-240' '  to  1-96' '. 

S.  jJi^stulata  {Trichoda  Acarus,  M.;  Ke- 
rona  ji^istulata,  Duj.), — White,  turbid, 
elliptical  or  oval  compressed,  attenuated 
at  both  ends,  and  ha^dng  a  band  of  im- 
cini  at  the  middle  of  the  belly.  Ehren- 
berg  has  seen  transverse  and  longitudinal 
division,  and  the  gro-wiih  of  gemmae.  In 
infusions  and  stagnant  marsh-water. 
1-144".  This  species  has  been  seen  in  the 
encysted  state  by  Stein  and  Schneider 
(xxix.  18).  The  white  colour  is  no  cha- 
racteristic, since  it  is  frequently  green 
from  food  received.  Schneider  {A.  N.  H. 
2  ser.  xiv.  p.  328)  observes  that  after 
exclusion  from  their  cysts  they  present 
a  remarkable  resemblance  to  Oxytricha 
caudata  -,  the  posterior  extremity  in  par- 
ticidar  is  always  bent  round  in  the  man- 
ner represented  by  Ehrenberg.  Pineau 
calls  this  animalcule,  in  his  history  of  a 
transformation  of  Vorticella,  by  mistake 
an  Oxytricha  (see  Ann.  d.  Sc.  Nat.  1848, 
ix.).  Cienkowsky,  Jiowever,  regards  both 
this  species  and  &f.  lanceolata  as  phases  of 
existence  of  the  same  being  as  Oxytricha 
Pellionella  and  O.  gihha.  I 

S.  Silur  us  (^Trichoda  Silurm,  Kerona  Si-  j 


liin/s,  M.,  I)uj .,  and  Pert}-). — Small, white, 
of  the  fonn  of  a  mussel ;  cilia  and  uncini 
rather  long.     In  fi'esh  water.     1-280". 

S.  appendiculata.  —  Elliptical,  white, 
small,  and  flat ;  cilia  and  styles  long ;  the 
setae  disposed  obliquely  in  fascicles.  In 
fresh  water.     1-280". 

S.  Histrio  (^Paramecium  Histrio,  Ke- 
rona Histi'io,  M.  and  Perty). — Elliptical, 
white;  middle  slightly  turgid,  termi- 
nated anteriorly  by  a  cluster  of  uncini ; 
no  setfe.  Ehrenberg  states  that  the  ab- 
sence of  the  three  posterior  setae  in  this 
and  the  following  species  is  remarkable, 
inasmuch  as  the  others  possess  them. 
Fission  transverse.  Amongst  Confervas. 
Dujardin  is  inclined  to  regard  this  as  a 
mere  variety  of  S.  {Kerona)  jJustulata. 

S.  lanceolata.  (  =  Kerona  lanceolata, 
Duj.  and  Perty)  (xxv.  343,  344).— Pale 
greenish ;  lanceolate  in  shape,  extremities 
equally  obtuse,  under  side  flat ;  it  has  a 
cluster  of  micini  near  the  mouth,  but  no 
styles.  Ehrenberg  saw  in  one  specimen 
a  simple  contractile  vesicle  on  the  left 
side,  below  the  mouth,  and  near  it  a 
large  oval  gland.  Green  Monads  and 
Bacillaria  may  be  seen  in  this  voracious 
animal,  surroimded  with  colourless  sto- 
mach-juice, (xxv.  343  represents  an 
under  view,  and  344  a  side  view.) 
Amongst  Confervae.  1-144"  to  1-120". 
(See  note  on  St.  pustulata.)  Encysted 
state  observed  (xxviii.  74-76). 


Genus  HALTERIA  (Duj.)  (XXYI.  31).— Body  nearly  globular  or  turbi- 
nate, surrounded  by  long,  very  fine,  retractile  cilia,  which  adhere  to  the  glass, 
and  by  their  sudden  contraction  enable  the  animal  to  change  its  place  briskly, 
as  if  by  leaping ;  a  row  of  very  strong  oblique  cilia  occupies  the  circum- 
ference. 

The  type  of  this  genus  is  Halieria  Granclinella  (XXYI.  31  a,  h,  c),  called 
by  Ehrenberg  TricJioclina,  and  placed  by  him  in  the  family  Yorticellina, 
along  with  species  totally  different.  Dujardin,  however,  more  correctly 
refers  them  to  the  family  called  Keronina  (see  p.  640). 

Genus  MITOPHORA  (Perty)  (XXYIII.  46,  47).— Body  small,  thicker 
behind,  having  on  one  side  a  row  of  large  cilia,  and  posteriorly  a  filament  of 
nearly  the  length  of  the  body,  and  either  with  a  simple  or  a  slightly  nodose 
extremity. 

MiTOPHORA  dubia  (xxviii.  46,  47). —  ,  the  other.     Movement  sluggish,  revolv- 
Hyaline ;    sometimes  filled  with   green  j  ing.     It  has  some  resemblance  to  Tri- 
corpuscles ;  with  the  characteristic  row  i  choda  prceceps  (M.).    1-450". 
of  larger  cilia  along  one  side,  and  few  on  I 

Genus  STICHOTRICHA  (XXYII.  43,  44).— Lancet-shaped,  cylindi'ical, 
elongated  anteriorly  and  flat ;  mouth  at  this  portion  ;  on  one  side  an  oblique 
row  of  cilia. 

Stichotricha  secitnda  (xxviii.  43,  |  molecules  or  chlorophyll-grains ;  cylin- 
44). — Hyaline ;  usually  filled  with  grey  i  drical  or  rather  compressed,  rounded  or 


OF  THE  EUPLOTINA.  645 


truncate  behind.  Cilia  on  ventral  sur- 
face short,  longer  before  and  behind; 
it  swims  rather  actively,  revolving  at  the 


same  time  -,  sometimes  it  crawls.   1-240' 
1-180". 


FAMILY  XII.— EUPLOTINA  or  EUPLOTA. 
(XXY.  345-353;  XXVI.  22,  30). 

Loricated ;  alimentary  canal  with  two  separate  orifices,  neither  of  which 
is  terminal.  Organs  of  locomotion  highly  developed,  similar  to  those  of  the 
preceding  family. 

This  family  bears  a  general  resemblance  to  the  genus  Asellus  among  the 
highly- developed  Entomostraca.  Organs  subservient  to  nutrition  are  di- 
stinctly seen  in  thi^ee  genera ;  and  one  is  remarkable  by  having  a  cylinder  of 
wand-like  teeth,  and  a  beautiful  rose-coloured  digestive  juice,  like  that  seen  in 
Nassida.  Granules  and  a  nucleus  are  found  in  two,  and  a  contractile  vesicle 
in  three  species;  self-division,  transverse  and  longitudinal,  has  been  ob- 
seiTed  in  one  ;  but  gemmae  are  not  produced.  One  form  is  green,  the  others 
are  colourless  or  whitish.     This  family  comjDrises  the  following  genera : — 


With  cilia ; 
no  styles. 


Teetli 
absent 


(  T^pf  ii     f  Head  distinguished  from  the  body    Discocephalus. 

Head  not  distinguished  from  the  body Himantophorus. 

^  Teeth  present  Chlamidodon. 

With  cilia,  claws,  and  styles Euplotes. 

This  family  Euplotina  corresponds  in  part  with  that  of  the  Ploesconiens 
of  Dujardin,  which  includes  animalcules  of  an  oval  or  renifonn  depressed 
figure,  not  contractile,  but  only  slightly  flexible,  and  invested  with  an  appa- 
rent shield  (lorica),  which,  however,  undergoes  diffluence  like  the  softer 
parts.  Mouth  furnished  with  \ibratile  cilia,  and  often  also  with  cuThi,  in 
the  form  of  styles  or  moveable  hooks.  They  swim  by  means  of  the  ^ibratile 
ciha,  or  crawl  by  the  aid  of  the  other  appendages. 

The  Ploesconiens  are  distributed  into  five  genera  : — Plcesconia  and  Chlami- 
dodon, with  a  visible  mouth,  the  latter  also  having  teeth ;  Dioplirys  and  Coc- 
cudina,  without  \isible  mouth:  in  the  former  the  cirrhi  or  processes  are  grouped 
at  the  two  ends,  in  the  latter  they  cover  the  under  surface ;  Loxodes  has  only 
vibratile  ciha. 

The  animalcules  of  the  genus  Plcesconia  seem  for  the  most  part  identical 
with  the  Eujjlotes  of  Ehrenberg ;  but,  as  the  identification  is  in  some  cases 
uncertain,  and  as  several  new  species  are  described  by  Dujardin,  we  shall 
subjoin  Plcesconia,  as  an  appended  genus,  along  with  Dioplirys  and  Coccudina. 

Perty  adopts  the  family  Euplota,  which  he  prefers  to  call  Euplotina,  and 
also  comprehends  in  it  the  Aspidiseina  (Ehr.)  and  the  Ploesconiens  (Duj.). 
Its  genera  are — Euplotes,  Himantophorus,  Coccudina  (Duj.),  w[iA  Aspidisca. 

Genus  DISCOCEPHALUS  (XXY.  345,  346).— Styles  and  teeth  wanting, 
but  uncini  present ;  the  head  is  also  distinguishable  from  the  body.  The 
organization  is  unknown,  only  the  non-vibratile  uncinated  locomotive  organs 
having  been  specially  observed,  the  characteristic  species  having  been  only 
casually  examined  by  Ehrenberg  during  his  travels  in  the  East.  The  genus, 
therefore,  must  be  held  a  doubtful  member  of  this  familv. 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


DiscocEPHALUS  votatovius  (XXV.  345, 
346). — Transparent;  head  smaller  than 
the  body ;  mouth  romided  at  both  ends. 


(xxv.  345  is  an  imder-,  and  xxv.  346  a 
side-view.)     In  the  Ked  Sea.     1-380". 


Genus  HIMANTOPHORIJS  (XXV.  347,  348).— Distinguished  by  the 
absence  of  styles  and  teeth,  by  having  numerous  uncini,  and  by  the  head 
not  being  distinct  from  the  body.  The  long  bent  hooks,  generally  in  pairs, 
appear  like  a  broad  band  upon  the  under  side,  and  serve  as  organs  of  loco- 
motion ;  near  them  is  a  row  of  cilia  extending  from  the  mouth  to  the  middle 
of  the  body.  The  mouth,  discharging  orifice,  and  numerous  vacuoles  are 
distinct.  At  the  posterior  margin  is  a  large  contractile  vesicle ;  between  the 
row  of  cilia  and  margin  on  the  right  is  a  series  of  glandular  (?)  spots.  Self- 
division  has  not  been  observed. 


HiMANTOPHORUS  CharoH  (M.)  (xxv. 
347,  348). — Transparent,  flat,  elliptical, 
anteriorly  slightly  truncated  obliquely ; 
cilia  short,  micini  short  and  slender.  The 
mouth  commences  anteriorly,  at  the 
lower  angle  of  the  triangular  bright  spot ; 
but  the  true  oesophageal  opening  appears 
to  be  within  the  curved  lorica,  at  the 


end  of  the  dorsal  row  of  cilia ;  the  anal 
opening  is  near  the  base  of  the  last 
cluster  of  fom'  to  six  comb-like  uncini, 
which  supply  the  place  of  styles,  (xxv. 
347  is  a  side-,  and  xxv.  348  an  imder- 
view.)  In  stagnant  water  and  ponds, 
amongst  decayed  leases.     1-180". 


Genus  CHLAMIDODON  (XXV.  349).— CHiated  mouth,  provided  with 
teeth ;  styles  and  uncini  absent ;  an  oval  transparent  lorica  or  shield  covers 
the  back,  and  projects  around  it;  a  margin  of  cilia  surrounds  the  body;  they 
are  longer  near  the  brow;  short  climbing  setae  probably  exist  posteriorly 
between  the  cilia.  There  are  distinct  vacuoles,  as  also  vesicles  containing  a 
beautiful  rose-coloured  fluid  ;  the  mouth  has  a  hollow  cylinder  of  wand-like 
teeth.  Internally  are  minute  green  granules  and  a  large,  oval,  bright  central 
nucleus.     Self- division  unknown. 


Chlamidodon  J/wemos?/we  (xxv.  349). 
— Flat,  elliptical,  sometimes  dilated  an- 
teriorly, as  shown  at  xxv.  349.  It  is  of 
a  clear  green  or  hyaline  hue,  with  bril- 
liant rose-coloured  vesicles;  delicate 
longitudinal  lines  are  seen  upon  the  sur- 


face of  the  animalcule,  and  appear  to  be 
situated  on  the  lorica.  Ehrenberg  counted 
sixteen  wand-like  teeth,  disposed  C3'lin- 
drically.  The  movement  is  quick  and 
powerfid,  as  in  Miplotes.  With  Zostera 
and  Scytosiplion.     1-570". 


Genus  EUPLOTES  (XXV.  350-353).— Locomotive  organs  highly  deve- 
loped and  various,  in  the  form  of  cilia,  styles,  and  uncini,  but  teeth  wanting. 
Digestive  vacuoles  have  been  filled  in  four  species  with  coloiu'ed  food ;  the 
termination  of  the  alimentary  canal  is  indicated  in  one  species  by  the  dis- 
charge, in  the  rest  by  the  projection  of  the  little  shield ;  the  digestive  juice 
is  coloiuiess ;  oval  or  round  simple  nuclei  occur  in  three  ;  a  single  contractile 
vesicle  exists  in  five,  and  in  a  sixth  two  such.  Self- division,  transverse  and 
longitudinal,  has  been  observed  in  one  species,  and  transverse  only  in  two  or 
four  others.     (See  general  remarks,  p.  645  ;  and  Plcesconia,  p.  647.) 

Perty  makes  the  remark  that  some  of  the  assumed  species  of  EupJotes  may 
be  modifications  of  the  same  being,  due  to  pressure  between  the  glasses 
during  examination,  since  the  so-called  lorica  is  only  relatively  hard.  The 
lorica  has  the  form  of  a  carapace  or  shield,  covering  only  one  surface,  lea\4ng 
the  under  one  free.  ''  The  styles,  which  are  trailed  along,  are,"  says  Lach- 
mann,  ^'  split  up  at  the  apex  into  as  many  as  eight  parts  in  many  species,— 
e.  cj.  in  E.  Patella,  in  which,  too,  one  style  bears  a  number  of  small  lateral 
branches.'' 


OF  THE  EUPLOTINA. 


647 


EuPLOTES  Patella.  —  Lorica  large, 
nearly  circular,  slightly  truncated  ante- 
riorly ;  margin  transparent,  broad ;  back 
elevated,  gibbous,  and  covered  with  a 
few  delicate  smooth  striae.  The  mouth 
is  ciliated  on  each  side  ;  the  oesophagus 
is  near  the  side,  below  the  middle  line, 
the  discharging  orifice  behind  the  base 
of  the  styles.     With  Lemuae.     1-280". 

E.  Giaron  (Trichoda  Charon,  M.) 
(xxv.  350-353). — Lorica  small,  ovate- 
elliptical,  slightly  trimcated  anteriorly, 
and  ha\dng  granular  striae  on  the  back ; 
twenty  to  forty  cilia  were  counted  by 
Ehrenberg,  but  no  setse;  a  contractile 
vesicle  and  one  or  more  nuclei  have  been 
seen.  In  standing  water  and  infusions. 
Schneider  has  seen  it  in  the  encysted 
condition.     1-280". 

E.  striatus. — Oblong,  elliptical,  slightly 
truncated  anteriorly,  uncini  only  upon 
the  posterior  part  of  the  body;  four 
smooth  striae  upon  the  back.  Fission 
longitudinal.  In  sea- water,  but,  accord- 
ing to  Perty,  also  in  freshwater  ponds, 
&c.    1-240.'' 

E.  appencUculatus. — Ovate-oblong,  ends 
rounded,  provided  with  oblique  styles 
and  four  straight  setae  upon  the  posterior 
part  of  the  body.  In  fresh  and  sea  water. 
1-240". 

This,  says  Stein,  is  the  Ploesconia  lon- 
giremis  of  Dujardin. 


E.  trmicatus. — Oblong,  with  smooth 
striae ;  unequally  truncated,  and  notched 
anteriorly.  It  has  setae  and  nimierous 
uncini.  The  styles  are  straight.  In  sea- 
water.     1-240". 

Both  this  and  the  preceding,  Perty  be- 
lieves to  be  phases  of  development  of 
E.  Charon  and  striatus. 

E.  monostylus. — Elliptical,  ends  round- 
ed, no  striae.  It  has  a  single  style,  like 
a  tail,  but  no  uncini.  In  sea-water. 
1-400". 

E.  aculcattis. — Oblong,  nearly  square, 
ends  rounded;  it  has  two  crests  upon 
the  back,  one  bearing  a  little  spine  in  the 
middle.  In  sea- and  pond-water.  1-430". 

E.  turritus. — Smooth,  nearly  circular ; 
it  has  a  long  erect  spine  on  the  centre  of 
the  back.     1-600"  to  1-430". 

E.  Cimex  {Trichoda  Cimex,  M.). — Ob- 
long elliptical,  and  smooth,  provided 
with  cilia,  styles,  and  uncini.  In  sea- 
water,  and,  says  Perty,  in  fresh  pond- 
water.     1-430". 

E.  viridis. — I^arge  (ample),  oblong, 
truncate  in  front,  with  a  central  obtuse 
tooth,  dorsum  flat;  granules  gxeen. 
1-480".     Berlin. 

JE.  affinis  (Perty)  =  Ploesconia  affinis 
(Duj.). 

E.  subrotundus  (Perty)  =  Ploesconia 
suhrotunda  (Duj.). 


Genus  PLCESCONIA  (Duj.). — Body  oval,  more  or  less  flattened,  enclosed 
by  an  apparent  lorica,  marked  by  longitudinal  ribs,  furnished  mostly  on  one 
of  its  plane  siu'faces  with  scattered,  fleshy,  thick  processes  in  the  form  of 
stiff  hairs,  or  of  non-vibratile  hooks,  yet  moveable  and  serving  the  piu'pose 
of  feet ;  on  the  other  surface,  with  a  row  of  vibratile  cilia  regularly  placed, 
and  becoming  finer  as  they  recede  from  the  anterior  towards  the  posterior 
end,  where  the  mouth  is  situated,  and  in  the  direction  of  which  they  vibrate. 

''  In  my  opinion,"  adds  Dujardin,  "  a  Ploesconia,  notwithstanding  its  ap- 
parent complexity  of  structure,  is  yet  an  animal  as  simply  organized  as  those 
pre\-iously  considered — having  a  simple,  fleshy,  homogeneous  substance,  which 
assumes  during  life  a  rather  complex  form,  but  loses  it  at  the  moment  of 
death,  ha\ing  no  membrane  or  fibre  to  sustain  it.  The  cilia  or  cirrhi,  though 
of  varied  form,  are  still  of  the  same  nature,  and,  I  should  say,  of  nearly  the 
same  consistence.  They  have  a  mouth  also,  but  no  anus ;  vacuoles  are  formed 
at  the  bottom  of  the  mouth,  as  a  result  of  an  impulsive  force  produced  by  the 
vibratile  cilia  on  the  surroimding  liquid,  or  they  may  be  hollowed  out  in  any 
part  beneath  the  surface ;  lastly,  disseminated  through  the  mass  are  granules 
varying  in  kind,  and  which  I  cannot  admit  as  determinate  organs  nor  as  ova." 

We  much  doubt  the  necessity  of  creating  this  new  genus,  since  aU,  or 
nearly  all,  the  species  referable  to  it  might  be  arranged  with  Euplotes.  Stein 
treats  Ploesconia  as  synonymous  ^ith  Euplotes  (Ehr.),  but  would  retain  the 
former  term  to  designate  a  new  genus  represented  by  PI.  Scutum  (Duj.),  a 
species,  indeed,  which  is  marked  by  the  French  natiualist  as  a  doubtful 
member. 


648 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


It  will  be  observed  that  Dujardin  denies,  as  usual,  the  existence  of  an 
anus ;  this  apertm-e  is,  however,  generally  stated  to  be  found  on  the  ventral 
surface,  near  the  posterior  extremity. 

Plcescoxia  PateUa= Euphtes  Patella 
(Ehr.). 

P.  Vannm. — Depressed,  oblong,  oval; 
very  transparent,  smooth,  without  strige, 
5  to  8  anterior  hooks  ;  and  7  to  8  straight 
styles  behind.     In  sea-water.    1-218". 

'p.  (?)  Scutum. — Larger  than  the  pre- 
ceding, with  the  band  of  vibratile  cilia 
extending  further  backwards,  and  the 
posterior  styles  inflected  and  sinuous. 

^*  This  species,"  says  Stein  (p.  158), 
"  differs  from  the  other  Euplotes  both  in 
having  prehensile  cilia  (uncini )  not  only 
on  the  ventral  surface,  at  the  poste- 
rior portion  of  the  body,  but  also  on  the 
dorsal  surface,  and  in  many  other  pecu- 
liarities." 

P.  halteata. — Oval,  rather  narrower  in 
front,  diaphanous,  with  5  striae  (ribs); 
the  band  of  cilia  extending  five-sixths 
the  length  of  the  body;  styles  few,  feeble. 
In  sea- water ;  no  hooks,  as  in  P.  Vannm. 
1-325". 

P.  Cithara. — Oval,  with  ten  regularly 
disposed  well-marked  ribs ;  the  row  of 
cilia  semicircular,  extending  two-thirds 


its  length ;  styles  not  long,  and  almost 
confined  to  the  posterior  extremity. 
In  stagnant  sea-water.  1-290"  to  1-275". 
P.  crassa. — Oval,  oblong;  thick,  but 
diaphanous,  with  some  faint  signs  of  ribs  ; 
the  band  of  cilia  little  curved,  and  ex- 
tending one-half  the  length;  6 to  8  cm-ved 


styles  at  anterior,  and  5  to  7  straight 
ones  at  posterior  extremity.  With  the 
preceding,  in  sea-water.     1-362". 

P.  CJiaron. — In-egularly  oval,  truncate 
in  front,  narrower  behind,  ^dth  well- 
marked  irregular  ribs;  styles  long,  not 
curved.  Differs  much  from  Euplotes 
Charon  (Ehr.). 

P.  affinis. — Differs  from  P.  Charon,  by 
its  habitat  being  in  fresh  water,  and  by 
having  its  anterior  portion  narrower, 
whilst  its  posterior  is  more  rounded  and 
less  plaited. 

P  (?)  subrottmda. — Oval,  thick,  gra- 
nular within ;  no  distinct  ribs ;  truncated 
and  fissured  in  front ;  styles  long,  thin  at 
each  end.  In  infusions.  1-535"  to 
1-475". 

Perty  found  it  mider  the  ice  in  a  pond 
near  the  Hospice  of  St.  Bernard,  and  sug- 
gests it  to  be  no  more  than  a  variety  of 
P.  affinis  with  indistinct  ribs  (strice). 

P.  (?)  radiosa. — Longer  than  the  pre- 
ceding, 1-520"  to  1-395'*",  ^\dth  long  styles 
radiating  from  each  extremity.  In  river- 
water. 

P.  longiremis. — Very  depressed,  irre- 
gularly oval,  dilated  on  the  side  support- 
ing the  cilia,  where  it  is  more  transpa- 
rent, with  3  to  4  slightly  prominent  large 
ribs ;  stvles  numerous,  verv  long  and 
flexible.'  In  sea- water.  1-400"  to  1-306". 

P.  aculeata  =  Euplotes  aculeatus  (Ehv.). 


Genus  DIOPHRYS  (Duj.)  (XXYL  22  a,  6).— Body  discoid,  irregular, 
thick ;  concave  on  one  side,  convex  on  the  other ;  with  long  styles  grouped 
at  each  end ;  no  mouth. 


DiOPHRYs  marina  (xxvi.  22  a,  b). — 
Oval,  with  a  longitudinal  excavation; 
terminated  in  front  by  5  great  vibratile 


cilia,  and  behind  by  4  to  5  very  long  geni- 
culate styles.     In  sea- water.     1-580". 


Genus  COCCUDINA  (Duj.)  (XXYI.  30  a,  &,  c).  —  Body  oval,  depressed 
or  nearly  discoid,  often  rather  sinuous  on  the  margin;  convex,  pitted  or 
granular,  and  glabrous  above ;  concave  below,  with  vibratile  cilia,  and  styles 
or  hooks,  ser\'ing  as  feet ;  without  mouth. 

Intermediate  between  Lo.vodes  and  Plcesconia,  having  the  appendages  of 
the  latter,  and  the  general  figiu^e  of  the  former.  Ehrenberg  has  left  the 
Coccudince  known  to  him  dispersed  among  the  species  of  Oxytricha  and 
Euplotes.     Aspidisca  should  probably  be  referred  to  this  genus. 

vibratUe.     In  marsh-water  and  swampy 
ponds.     1-965". 

C.  crassa.  —  Oval;  larger  and  appa- 
rently truncated  behind ;  contracted  and 
sinuous  in  front;  convex  above,  with 
feeblv-marked  ribs  ;  anterior  appendages 


CoccuDiNA  costata. — Oval,  obliquely 
contracted,  and  sinuous  in  front ;  convex 
and  furrowed  beneath,  where  from  5  to  6 
very  prominent  tubercular  ribs  are  found, 
supporting  longcilia :  appendages  grouped 
at  each  end ;  the   anterior  thinner  and 


OF  THE  ROTATORIA. 


649 


in  the  form  of  hooks ;  posterior,  of 
straight  styles.  1-20".  Marine,  among 
corallines. 

C.  polypoda  (xxvi.  30  a,  b,  c). — Oval, 
sinuous  in  front ;  convex  above,  and 
marked  with  from  7  to  8  narrow  ribs; 
flat  below,  and  funiished  with  numerous 
long  and  flexible  styles.  In  stagnant 
sea-water. 

C.  Cicada. — Oval,  very  convex  above, 
granular,  without  costae  ;  margin  round- 
ed ;  concave  beneath,  and  there  provided 
with  long  and  flexible  styles.  Appears 
the  same  as  the  Trichoda  Cicada  of  Miiller, 
but  not  as  its  supposed  synonym  Oxy- 


tricha  Cicada  (Ehr.),  which  is  like  the 
Coccudina  costata  rather  than  C.  Cicada. 
1-812". 

C  (?)  Cimex  =  Stylotujchia  Cimex(Ela.v.). 

C.  reticidata. — A  name  provisionally 
applied  to  an  animalcule  found  in  the 
Seine,  having  a  granular  and  reticulated 
surface,  and  large  styles  at  each  end. 
1-578". 

Q.  crystallina  (Perty). — Hyaline,  with 
from  6  to  7  long  costae  on  the  dorsum, 
and  very  short  cilia.  Outline  roimd.  The 
costse  are  less  elevated  than  in  C  costata. 
Wet  moss  and  turf  on  the  Alps.  1-900" 
to  1-600". 


OF  THE  GROUP  ROTATORIA   (p.  392). 

(Plates  XXXII.-XL.,  and  part  of  XXY.) 

Those  animalcules  which  are  included  in  the  great  di\dsion  Rotatoria  are 
either  destitute  of  a  nervous  system,  or  have  merely  an  isolated  ganglion 
near  the  head,  representing  the  brain,  with  a  few  nervous  threads  proceeding 
from  it  to  the  body.  They  have  no  pulsating  heart,  nor  true  blood-vessels  in 
which  the  blood  circulates.  The  fluid  apparently  representing  the  blood 
occupies  the  cavity  of  the  body  and  bathes  the  external  siu'faces  of  the  various 
viscera,  as  in  the  lower  Crustacea.  The  alimentary  canal  is  tubular,  variously 
constricted  at  intervals,  often  di\4dcd  into  segments,  each  of  which  appears  to 
perform  special  functions.  One  segment,  near  the  ujDper  extremity  of  the 
canal,  is  pro\^ded  with  a  pair  of  moveable  appendages,  between  which  all  the 
food  swallowed  has  to  pass,  and  which  may  be  regarded  as  teeth  or  jaws, 
probably  analogous  to  the  gastric  teeth  of  Crustaceans.  In  many  species 
there  are  csecal  prolongations  of  the  stomach ;  whilst  the  walls  of  the^organ  are 
thick  and  cellular,  having  a  glandular  aspect.  The  alimentary  canal  is,  mth 
some  remarkable  exceptions,  furnished  with  an  orifice  at  each  extremity,  or 
mouth  and  aniLS, — the  latter  usually  opening  into  a  cavity  termed  the  cloaca, 
or  common  outlet  for  the  intestine,  the  oviduct,  and  the  (so-called)  water- 
vascular  canals.  The  interior  of  the  canal  is  variously  supplied  with  cilia, 
which  are  in  constant  motion.  The  caecal  and  cellular  appendages  are  sup- 
posed to  be  glandular ;  but  their  functions,  as  well  as  relations  to  the  liver 
and  other  chylopoetic  organs  of  higher  animals,  are  doubtful. 

The  character  and  instruments  of  the  respiratory  functions  in  the  Rotatoria 
ai-e  alike  doubtful,  but  most  probably  they  are  performed  by  the  water  vas- 
cular canals.  These  are  two  slender  tubes  (XXXYI.  6  e,(j)  springing  fi'om 
the  cloaca  near  the  anal  outlet,  and  proceeding  upwards  on  each  side  of  the 
intestine  towards  the  head,  where  they  branch,  and  sometimes  the  two 
anastomose,  at  others  probably  terminate  in  cuh-de-sac.  These  canals  com- 
mence at  a  pulsating  organ  (XXXYI.  6  v ;  XL.  5),  common  to  both,  and 
connected  with  the  cloaca.  In  various  parts  of  their  course  they  are  fur- 
nished with  pyriform  appendages  (XXXYI.  6  a)  (tags)  varying  in  number 
from  two  to  eight  on  each  side.  In  the  interior  of  each  tag  is  a  single 
large  cilium,  which  exhibits  an  incessant  motion,  resembling  the  flickering 


G50  SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 

flame  of  a  candle,  and  which  most  probably  promotes  the  circulation  of  the 
water  contained  in  the  canals.  This  water  is  apparently  received  from  the 
cloaca  into  the  pulsating  appendage,  and  from  it  transmitted  to  the  various 
parts  of  the  tubular  system, — a  fact  especially  confirmed  by  Cohn's  observa- 
tions on  Brachionus  m'llitaris.  Hence  these  water-vascular  canals,  with 
theii'  vibratile  appendages,  appear  designed  to  convey  streams  of  fresh  water 
to  the  interior  of  the  animal,  and  thus,  by  exosmosis,  aerate  the  fluid  filling 
the  body  of  the  animal, — the  latter  being  continually  driven  to  and  fro  during 
the  active  muscular  movements  by  which  the  creature  alters  its  contour. 

The  Rotatoria  are  provided  with  a  reproductive  apparatus,  the  female 
organs  being  remarkably  large  and  conspicuous  (XXXVI.  4/).  In  the 
majority  of  species  the  latter  is  the  only  portion  that  has  hitherto  been  dis- 
covered ;  but  in  several,  male  organs  have  been  found  on  separate  indivi- 
duals, indicating  the  bisexual  nature  of  the  class — at  least  demonstrating 
the  dioecious  character  of  some  of  the  species,  a  feature  which  will  probably 
be  found  to  characterize  the  entire  family.  The  ovary  consists  of  a  very  thin 
bag  of  structureless  membrane  (XXXVI.  4/),  distended  with  clear  fluid  full 
of  granular  molecules,  amongst  which  are  some  cellular  nuclei.  The  latter 
successively  attract  around  them  portions  of  the  granular  fluid,  thus  forming 
ova.  In  several  species  two  distinct  kinds  of  ova  are  produced  by  the  same 
individual,  one  being  a  true  generative  product,  the  other  a  modified  ex- 
ample of  gemmiparous  generation,  and  its  growth  independent  of  any  sexual 
process.  The  ovary  communicates  with  the  cloaca  by  means  of  a  narrow  but 
dilatable  oviduct.  In  examples  of  male  animals  that  have  been  discovered, 
there  is  a  remarkable  absence  of  all  viscera,  except  the  organs  of  reproduction 
(XXXVI.  7,  8).  "Whether  all  the  Rotatoria  are  dioecious,  or  whether  some 
are  hermaphrodite,  the  male  organs  having  hitherto  escaped  detection,  re- 
mains to  be  ascertained. 

The  bodies  of  the  Rotatoria,  unlike  those  of  the  Polygastric  Infusoria,  re- 
tain a  determinate  form,  never  developing  external  gemmae,  nor  dividing  by 
spontaneous  division.  Even  on  emerging  from  the  e^^,  they  possess  all  the 
essential  featuresof  the  matured  animal(XXXVII.  16),neither  passing  thi'ough 
a  larval  state  nor  being  subject  to  metamorphosis  like  Crustaceans  and  Insects. 
In  the  young  animal  some  of  the  organs,  especially  the  ciliated  disks  and 
other  external  appendages,  are  imperfectly  developed,  but  they  imdergo  httle 
subsequent  changes  beyond  an  increase  of  size  and  definitivcness.  Some 
organs,  as  the  red  eye- spot,  often  disappear  as  the  animal  progresses  to  ma- 
turity. The  anterior  extremities  of  the  Rotatoria  are  furnished  with  various 
arrangements  of  the  disks  or  bulbs  supporting  niunerous  cilia  (XXXVI. 
1  a  and  4  a).  These  combine  to  form  the  rotatory  organs,  so  designated  from 
the  wheel-like  aspect  which  they  present  when  fully  expanded  and  with  the 
cilia  in  motion.  Though  destitute  of  true  articulated  limbs,  some  species  {e.g.  of 
Melicertci)  have  appendages  not  imlike  the  palpi  of  Crustaceans  and  Insects,  and 
which  are  probably  tactile  (XXXVI.  18 ;  XXXVII.  17  d).  Many  fonns  are 
provided  with  a  prolongation  of  the  posterior  part  of  the  body,  which  is  often 
pointed  (XXXVIII.  1),  and  with  the  articulations  slipping  into  one  another 
like  the  joints  of  a  telescope.  This  organ  is  sometimes  furnished  with  a 
terminal  disk  (XXXVII.  17  h),  and  is  used  like  the  tail  of  the  leech,  as  an 
organ  of  attachment.  In  other  cases  the  disk  is  wanting,  and  its  place  sup- 
plied by  one  or  two  digital  appendages  (XXXVI,  4  h),  employed  as  anchors  ; 
whilst,  in  swimming,  the  entire  organ  appears  to  become  a  rudder,  regulating 
the  direction  in  which  the  animal  moves. 

The  entire  animal  is  invested  by  a  thin  peUucid  membrane,  which,  from 
its  extreme  tenuity  and  transparency,  readily  allows  the  examination  of  the 


OF  THE  EOTATOEIA.  651 

internal  organs  whilst  the  creatui'e  is  alive  and  the  viscera  fulfilling  their 
functions, — a  circumstance  that  has  even  made  these  creatures  the  favomites 
of  the  microscopic  observer. 

Modes  of  Obsekving  the  Rotatokia. — The  magnifying  powers  most  useful 
in  the  examination  of  the  Rotatoria  are  those  varying  from  200  to  400  linear. 
For  watching  their  general  habits,  an  object-glass  of  a  half- inch  focus, 
which  with  an  eye-piece  gi\^ng  a  power  of  about  70,  is  ample ;  but  for  ex- 
amining their  internal  organization,  one  of  about  300,  having  an  object-glass 
of  from  one-third  to  one-sixth  of  an  inch,  is  the  most  useful ;  for  the  special 
examination  of  more  minute  structural  details,  still  higher  powers  are  occa- 
sionally, but  not  frequently,  needed.  We  have  already  remarked  that,  from 
the  transparency  of  their  bodies,  the  Rotatoria  can  be  watched  with  much 
ease,  theii'  internal  organs  being  distinctly  visible ;  and,  as  these  latter  are 
often  equally  transparent  with  the  general  integument,  their  contents,  and 
the  fimctions  they  perform,  can  be  investigated  with  httle  difficulty.  When 
theii^  general  habits  are  subjects  of  investigation,  it  is  obvious  they  must  be 
allowed  much  of  the  freedom  enjoj^ed  in  their  natural  condition.  Por  this 
piu-pose  they  may  be  introduced  into  a  small  phial  of  thin  white  glass  with 
a  long  narrow  strip  of  similar  material  in  its  interior ;  the  latter  being  so 
fixed  as  to  be  nearer  one  side  of  the  phial  than  the  other.  A  blade  of  grass 
or  one  or  two  stalks  of  hay  may  now  be  introduced  between  the  strip  of  glass 
and  the  proximate  side  of  the  bottle ;  these  will  attract  the  animalcules  and 
bring  them  within  the  range  of  the  magnifying  power.  If  the  phial  be  now 
filled  with  water  containing  the  Rotatoria,  they  will  soon  find  their  way  to 
the  vegetable  matter,  especially  if  the  bottle  stands  for  awhile  in  the  sun, 
with  the  side  to  which  the  plant  is  affixed  turned  to  the  light.  The  whole 
may  now  be  placed  under  the  microscope  and  readily  examined  through  the 
lower  magnif}ing  powers.  To  some  extent,  the  same  object  may  be  more 
readily  attained  by  merely  transferring  small  fragments  of  the  half-decayed 
vegetation  floating  in  the  water  containing  the  animalcules,  along  with  a 
drop  or  two  of  the  water  itself,  to  a  glass  slide,  covering  it  over  with  a  piece 
of  thin  microscopic  glass.  But  in  this  case  the  movements  of  the  creatures 
are  less  free,  especially  if  they  happen  to  be  of  the  larger  Idnds,  such  as  the 
FJoscularke.  These  are  often  chary  of  emerging  from  their  protecting  cases 
imless  the  coast  be  clear  of  all  impediments.  But  the  freedom  of  motion,  so 
important  to  the  accurate  observation  of  their  habits,  wholly  prevents  the 
examination  of  their  internal  structure.  Their  perpetual  gjTation  renders  it 
impossible  to  trace  either  the  forms  or  relative  position  of  the  viscera ;  con- 
sequently they  must  be  controlled.  This  may  partly  be  accomplished  by 
introducing  them  between  the  glasses  already  recommended  without  the 
intervention  of  any  vegetable  or  other  foreig-n  substance.  In  this  case  care 
must  be  taken  to  adjust  the  relations  between  the  size  of  the  thin  glass 
covering  and  that  of  the  drop  of  water.  If  the  former  be  large  and  the  latter 
small,  the  chances  are  in  favour  of  the  aninjalcules  being  cnished.  If  these 
conditions  are  reversed,  their  motions  will  not  be  sufficiently  restrained, 
neither  can  the  water  be  preserved  fi'om  disturbance  and  vibration.  Hence 
care  in  hitting  the  medium  of  these  conditions  is  essential.  The  smaller  the 
drop  of  water  the  thinner  will  be  the  fluid  film  when  the  protecting  glass  is 
placed  upon  it,  and  the  more  effectually  wiU  the  vagrant  habits  of  the 
creatures  be  controlled.  Sometimes  it  becomes  necessary  to  rupture  the 
animals  by  further  compression,  even  whilst  under  examination.  The  diffi- 
culty is  to  accomplish  this  without  forcing  them  out  of  the  field  of  the  instru- 
ment. It  may  be  accomplished  by  means  of  a  common  sewing  needle  fitted 
into  a  handle,  by  which  pressure  may  be  applied  gently  but  firmly  to  the 


652  SYSTEMATIC  HISTORY  OF  THE  I>^FrSORIA. 

thin  glass.  But  this  object  can  be  still  better  attained  by  means  of  one  of 
the  compressoria  provided  by  opticians :  the  pressure  being  eiFected  with  a 
fine  screw,  the  movement  can  be  regulated  \\ith  the  utmost  nicety.  Thus 
the  animal  can  be  merely  fixed  in  its  position,  whilst  its  Tital  functions  pro- 
ceed without  interruption.  On  increasing  the  pressure,  we  obtain  increased 
transparency  by  reducing  the  thickness  of  the  animal;  and  on  carrying  the 
motion  still  further,  we  can  rupture  the  integument,  when  the  viscera  become 
detached  and  discharged  through  the  fissure.  Thus  their  minute  organization 
can  be  more  accurately  ascertained  than  when  retained  in  situ.  In  some 
cases  the  forms  of  the  various  viscera  can  be  readily  ascertained  from  the 
different  hues  which  characterize  them,  but  in  the  majority  of  Rotatoria  this 
guide  fails  us.  Consequently  observers  have  long  adopted  a  plan  of  feeding 
the  animals  with  brightly- coloured  pigments,  such  as  cannine  and  indigo, 
which  many  of  the  creatures  consume  with  avidity :  a  very  small  quantity  of 
the  colour  should  be  rubbed  up  with  a  httle  water,  as  if  for  artistic  pui'poses. 
If  the  live -box  be  used  in  examining  the  creatures,  with  the  water  contain- 
ing the  animalcules  a  little  of  this  colour  must  be  mixed  prior  to  the  cover 
being  placed  upon  them.  But  when  a  common  glass  slide  is  employed,  it 
generally  suffices  to  dip  a  camel's-hair  pencil  iato  the  diluted  pigment  and 
apply  it  to  the  edge  of  the  thin  glass.  The  colour  usually  flows  between  the 
g-lasses,  and  difiuses  itself  thi^ough  the  water  sufficiently  to  answer  every 
purpose.  Two  objects  are  now  attained.  The  minute  coloui'ed  particles  are 
thrown  into  active  motion  by  the  ciliary  movements  of  the  trochal  wreaths, 
beautifully  demonstrating  the  force  and  direction  of  the  aqueous  vortices  set 
up  by  the  animalcule ;  and  by  noting  the  direction  taken  by  such  of  the 
particles  as  are  swallowed,  the  position  of  the  mouth  and  oesophageal  canal 
can  be  traced.  These  particles  usually  accumulate  in  the  stomach,  distend- 
ing its  parietes ;  and  as  the  bright  colour  of  the  pigment  contrasts  strongly 
with  the  transparent  walls  of  the  viscus,  its  size,  form,  and  position,  as  well 
as  the  structure  of  its  walls,  can  be  readily  made  out.  By  prolonging  the 
observation,  the  same  agent  enables  us  to  ascertain  the  dii'ection  of  the 
intestine,  anus,  and  cloaca, — since,  when  the  stomach  becomes  inconveniently 
full,  the  creature  usually  everts  the  cloaca,  brings  the  anal  oiifice  into  contact 
with  the  suiTounding  fluid,  and  suddenly  empties  the  stomach  or  bowel  of  its 
contents. 

There  are  practical  disadvantages  attending  the  use  of  carmine  and  iadigo, 
some  of  which  Mr.  A\Tiite  appears  to  have  overcome  by  substituting  the  red 
pigment  which  lines  the  cornea  of  the  eye  of  the  common  house-fly  (Microsc. 
Journ.  ii.  p.  282).  By  means  of  a  finely-pointed  knife,  or  sharp-edged  needle, 
the  large  cornea  can  easily  be  detached  from  the  head  of  the  insect ;  whilst 
a  small,  stiff*  camel-haii',  or  (still  better)  a  small  sable  pencil  suffices  to  wash 
the  pigment  out  of  the  internal  concavity  of  the  detached  cornea. 

It  is  occasionally  desirable  to  examine  the  animals  by  reflected  instead  of 
transmitted  light,  in  order  that  their  true  colours  may  be  exhibited,  as 
Mr.  Gosse  has  pointed  out  in  the  instance  of  Philodina  citrina. 

Localities  foe  Eotatoria.  —  These  are  exceedingly  diversified,  vaiying 
from  the  wide  ocean  to  the  dried-up  sediment  of  the  water-spout.  There 
are  few  cii'cumstances  under  which  water  exists,  in  which  Eotatoria  may  not 
be  found,  though  they  disUlie  it  when  its  contents  are  undergoing  decom- 
position. Consequently,  though  they  occiu'  in  all  vegetable  infusions,  they 
are  only  to  be  found  when  the  first  stage  of  decomposition  has  passed  away, 
and  they  usually  disappear  again  when  the  water  becomes  putrid  and  ofl'en- 
sive.  After  the  Monadina,  Paramccia,  and  other  smaller  Infusoria  have  run 
their  course,  and  in  large  mea.sure  disappeared,  the  Eotatoria  occupy  their 


OF  THE  ROTATORIA.  653 

places, — a  circumstance  that  has  led  some  obsei^ers  to  suggest  the  probability 
of  some  of  these  lower  forms  being  the  larval  states  of  the  higher  ones — a 
view  now  known  to  be  erroneous. 

Some  species,  especially  the  Eotifer  vulgaris,  are  common  wherever  water 
has  remained  for  a  little  time  without  distui'bance,  in  cisterns,  depressions 
in  the  gutters  of  houses,  saucers  of  flower-pots,  and  similar  situations.  A 
few  forms  have  been  found  in  the  interiors  of  vegetable  cells.  Thus  Rotifer 
vulgaris  occm^s  in  the  leaf-cells  of  Sphagnum,  and  in  the  clavate  branches  of 
Vaucheria,  feeding  upon  the  contained  chlorophyll.  Notommata  parasitica 
and  N.  petroynyzon,  found  within  the  spheres  of  Volvox  globator,  in  like 
manner  consume  the  little  masses  of  green  protoplasm ;  whilst  Notommata 
WernecTcii,  like  the  Rotifer,  occui^s  in  the  cells  of  Vaucheria. 

They  often  abound  in  the  damp  moss  from  the  neighboui^hood  of  bogs, 
streams,  and  waterfalls.  But,  besides  these  special  situations,  some  of  them 
are  to  be  found  in  almost  every  ditch  and  pond  in  which  Lemnae,  Confervae, 
and  other  decaj'ing  masses  of  vegetation  abound.  Sometimes  they  play  round 
the  plants  \vith  incessant  action,  piLshing  their  slender  bodies  into  every 
recess  in  which  food  may  liu'k,  then  backing  out  again  as  cleverly  as  any  of 
their  larger  aquatic  companions  can  do  with  fin  and  tail, — now  anchoiing 
themselves  to  some  projecting  point  by  means  of  their  flexible  pseudopodia, 
di'awing  in  their  trochal  disks  with  apparent  alarm  if  any  other  creature 
bnishes  past  their  resting  place  with  unmannerly  rudeness ;  then,  forgetting 
their  fears,  they  agani  evolve  theii^  ciliated  wheels,  loosen  from  their  anchor- 
age, and  launch  away  into  the  clear  stream,  displaying  the  varied  modes  of 
progression  so  characteristic  of  different  species.  But  it  is  only  some  of 
the  forms  which  indulge  these  vagrant  habits.  The  higher  forms,  such  as 
Limnias,  Melicerta,  Floscularia,  Lacinularia,  and  Stephanoceros,  are  quiet 
stay-at-home  matrons,  at  least  after  sowing  the  wild  oats  of  their  youthful 
days.  For  a  short  time  only  after  leaving  the  ovum  do  they  roam  ^vild  and 
free.  They  soon  settle  down,  attaching  themselves  by  their  false  feet  to  some 
fixed  resting  place,  where  they  spend  the  rest  of  their  lives  in  sober  tran- 
quillity. These  home-birds  must  be  sought  for  amongst  the  stems  and  leaflets 
of  Ceratopliyllum,  Cliara,  and  the  water  Ranunculus,  more  frequently  occurring 
in  the  clearer  streams  and  ponds  than  do  many  of  their  smaller  allies. 

Tnlilie  the  Monadina  and  other  lower  Infusoria,  the  Rotatoria  rarely  oceui^ 
in  such  profusion  as  to  coloiu'  the  water.  It  is  occasionally  rendered  turbid 
and  milky  by  Brachionus  Palea,  which,  in  such  cases,  occurs  in  vast  profusion. 
BracTiionus  urceolaris  and  B.  ruhens  sometimes  present  the  same  conditions. 
Typhlina  viridis,  found  by  Ehrenberg  in  Egyj)t,  coloured  the  water  green . 
Lacinularia  forms  small  transparent  gelatinous  masses.  Limnias  annulatus 
occasionally  studs  the  leaves  of  water-plants  in  such  number  as  visibly  to 
clothe  them  in  russet  broAvn ;  and  groups  of  Conochilus  Volvox  appear  in 
small  clusters,  adherent  by  the  extremities  of  their  pseudopodia,  like  a  group 
of  tadpoles  dipped  in  colourless  jeUy,  from  which  they  can  protnide  their 
heads  or  retract  them  at  will ;  but  sociality  does  not  usually  characterize 
the  Rotatoria  as  it  does  Euglena  and  similar  forms.  It  is  only  when  the 
parasitic  species  have  taken  possession  of  some  remarkably  favoiu-able 
locaHty  that  they  so  abound  as  to  affect  the  aspect  of  the  plants  on  which 
they  dwell,  and  thus  force  themselves  on  the  attention  of  the  obseiwer. 
Usually  they  must  be  sought  for  in  a  systematic  way,  without  any  external 
indications  whether  a  pool  will  prove  productive  or  barren.  We  have,  how- 
ever, rarely  been  disappointed  on  examining  the  green  and  foul-looking 
drainage  from  the  manure  heap  in  the  farm-yard.  Amidst  its  swanns  of 
Euglence  we  have  usually  found  a  rich  supply  of  Rotatoria.     The  true  micro- 


654  SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 

scopist  must  not  be  afraid  of  soiling  his  hands,  or  have  a  weakness  for  kid 
gloves.  Some  few  Rotatoria  assume  the  habits  of  Entozoa.  Albert ia  ver- 
micularis  was  found  by  Dujardin  in  the  abdominal  ca\'ities  of  the  earthworm 
and  in  the  intestine  of  Limacina ;  whilst  Albertia  crystallina  was  discovered 
by  Schultze  in  the  intestine  of  Nais  littoraUs. 

Capture  of  Rotatoria. — The  modes  of  captimng  the  Rotatoria  must  vary 
with  the  species  sought,  as  will  be  e\-ident  from  the  remarks  made  in  the 
preceding  section.  The  simj^lest  mode  of  obtaining  the  majority  of  the  forms 
is  to  collect  a  quantity  of  Confervas,  Lemnse,  or  the  half-decaying  masses  of 
the  diiferent  pond-weeds,  fiUing  the  vessel  with  water  from  the  pool  in  which 
plants  were  growing.  We  have  usually  found  the  shallow  margins  of  the 
pond  most  productive.  On  reaching  home,  the  vegetable  mass  must  be  well 
stirred  up  in  the  water,  in  order  to  detach  the  animalcules  from  the  plants  to 
which  they  cling ;  and,  before  they  have  time  to  re-attach  themselves,  the 
water  must  be  poured  off  into  another  vessel,  through  a  piece  of  muslin  or 
very  fine  net.  All  the  coarse  material  is  thus  got  rid  of,  nothing  passing 
through  the  strainer  but  water  rendered  turbid  hj  fine  particles  of  half- 
decayed  vegetation  suspended  in  it.  But  along  \\ix\i  these  vegetable  atoms 
the  Rotatoria  Avill  also  pass  into  the  receiving  vessel,  which  must  be  allowed 
to  stand  for  a  while,  allowing  the  sediment  to  sink  to  the  bottom,  where 
it  will  be  followed  by  the  animalcules  which  find  nutriment  in  the  half- 
decayed  mass.  A  small  portion  of  this  sediment  may  noAv  be  taken  up  by 
means  of  a  narrow  glass  tube,  one  end  of  which  must  be  introduced  to  the 
bottom  of  the  vessel,  whilst  the  opposite  one  is  closed  by  the  finger  or  thumb. 
On  removing  the  latter,  the  sediment  iTishes  up  into  the  tube ;  and  if  the 
upper  end  of  the  tube  be  again  closed  as  before,  the  contained  material  can  be 
transferred  to  the  live-box  or  the  glass  slide.  If  the  tube  be  held  for  a  few 
moments  in  a  vertical  position,  the  upper  part  being  still  closed  with  the 
finger,  the  vegetable  matter  and  its  accompanying  animalcules  vnW.  sink  to 
the  lowest  part  of  the  water ;  consequently  the  first  di'op  escaping  fi^om  the 
lower  end  of  the  tube  will  usually  be  richer  than  those  that  follow.  If  the 
di'op  be  received  upon  a  glass  sHde,  it  must  be  covered  over  vdih.  a  piece  of 
thin  glass,  when  it  is  ready  for  the  microscope,  and,  unless  the  pond  has  been 
uncommonly  barren,  the  instrument  will  reveal  a  rich  harvest  of  Algge,  Con- 
fervae,  Desmidieae,  Diatoms,  and  Polygastrica ;  whilst  amongst  all  these  the 
Rotatoria  ^vill  be  found  sailing  from  point  to  point,  exploring  all  the  recesses 
between  the  vegetable  fragments, — now  quiescent,  as  if  contemplating  the 
contents  of  the  larder,  then,  as  if  dissatisfied  with  the  prospect,  sailing  away 
to  some  more  promising  pasture.  But  when  a  tempting  nook  presents  itself, 
this  restless  locomotion  ceases,  and  they  attach  themselves  to  some  fixed  point 
either  by  means  of  a  disk-like  foot  or  by  using  its  terminal  joints  as  an  anchor, 
— their  trochal  disks  being  for  the  time  drawn  in,  and  comfortably  lodged  in 
the  anterior  part  of  the  body.  Its  position  being  faiiiy  secui^ed,  the  animalcule 
evolves  its  wheels,  at  first  slowly,  but  soon  increasing  their  speed.  A  violent 
commotion  amongst  the  atoms  abounding  in  the  water  soon  indicates  the  pro- 
duction of  a  miniature  whirlpool,  which  brings  a  contmuous  stream  of  edible 
matter  within  the  reach  of  the  hungry  traveller.  But,  though  hungry,  he  is 
a  dainty  gentleman,  and  chooses  to  select  his  fare.  The  bulk  of  what  is 
drawn  towards  him  by  the  vortex  he  has 'created,  not  suiting  his  taste,  is 
suffered  to  flow  by,  in  a  continuous  stream,  like  that  left  by  the  rocket  in  its 
flight.  But  everything  is  not  thus  allowed  to  pass :  the  teeth-like  jaws  of 
the  animalcule  are  constantly  playing  against  each  other  with  desperate 
energy,  whilst  sudden  jerks  and  contractions  indicate  that  the  animalcule  has 
made  a  capture  ;  and  though  it  is  not  always  easy  to  see  his  prey  pass  down 


OF  THE  EOTATOEIA.  655 

his  gullet,  the  gradual  expansion  of  his  stomach  proves  that  he  is  not  labour- 
ing in  vain.  The  Monads  find  to  their  cost  that  he  is  a  real  Triton  amongst 
the  minnows. 

Another  mode  of  capturing  similar  forms  is  by  emploj'ing  a  small  net,  of 
very  fine  muslin  firmly  fastened  to  a  ferruled  hoop  of  brass  or  iron,  a  few 
inches  in  cii^cumference,  and  capable  of  being  fitted  to  a  walking-stick  or 
fishing-rod.  It  has  been  recommended  that  the  exterior  of  this  hoop  should 
be  grooved,  so  that  nets  of  various  degrees  of  fineness  can  readily  be  employed 
— these  being  attached  merely  by  means  of  an  elastic  ring  of  vulcanized 
indian-rubber,  di^awn  over  them  and  fitting  into  the  metallic  groove.  By 
means  of  a  net  of  this  character,  the  central  and  deeper  parts  of  a  pond  can 
be  searched,  as,  if  the  gauze  be  sufficiently  fine,  the  net  will  retain  the  larger 
Rotifera,  whilst  the  water  passes  fi^eely  through  it.  After  making  a  succes- 
sion of  sweeps  through  the  pond,  the  net  may  be  everted  into  a  receiver  con- 
taining clear  water,  and  with  a  little  manipulation  the  animalcules  adhering 
to  it  may  be  washed  into  the  vessel.  By  means  of  the  same  net  the  fluid 
may  be  concentrated  until  at  length  the  rich  products  of  an  hour's  fishing 
may  be  carried  home  in  an  ounce  phial.  But  the  muslin  must  be  very  fine, 
or  the  richest  of  the  game  will  escape.  When  the  large  and  exquisitely 
beautiful  Floscularian  Rotatoria  are  the  objects  of  search,  a  different  method 
must  be  followed.  It  is  but  occasionally  that  they  can  be  met  with ;  conse- 
quently the  student  must  be  prepared  to  give  time  and  labour  before  he 
succeeds  in  discovering  these  lovely  objects ;  but  they  are  well  worth  the 
price.  As  before  obser^^ed,  Melicerta,  Stejphanoceros,  and  similar  forms  are 
foimd  attached  to  the  slender  stems  and  subdivided  leaves  of  CeratopTiyl- 
lum,  Myriopliyllum,  Ranunculus  aquatilis,  the  Charce,  and  similar  plants. 
The  method  of  search  which  we  have  found  the  most  successful  has  been  to 
carry  with  us  to  the  field  a  narrow  phial  of  clear  white  glass  or  a  chemist's 
test-tube,  into  which  portions  of  such  plants  as  a  pond  may  contain  may  be 
introduced  along  with  a  little  clean  water.  The  unaided  eye,  when  experi- 
enced, soon  ascertains  the  presence  or  absence  of  the  objects  sought  for ;  but 
the  search  may  be  further  facilitated  by  means  of  a  pocket-lens  of  low 
magnifying  power.  If,  after  selecting  several  fragments  di^awn  from  different 
parts  of  a  pond,  these  do  not  reveal  traces  of  some  of  the  Ploscularians,  it  is 
probable  they  do  not  exist  there,  and  we  may  proceed  to  some  new  fishing- 
groimd ;  but  if  an  isolated  individual  be  detected,  every  clump  of  aquatic 
vegetation  in  the  pond  should  be  carefully  searched ;  for,  as  is  the  case  mth 
Volvox  and  many  other  microscopic  organisms,  there  will  be  found  in  some 
part  of  the  water  a  colony  where  Malthusianism  has  no  place,  and  to  which 
the  isolated  individual  first  found  bears  the  same  relation  as  the  trappers  and 
backwoodsmen  of  the  west  do  to  the  swarming  communities  of  Boston  and 
New  York. 

One  remarkable  circumstance  must  be  borne  in  mind  by  the  animalcule- 
hunter.  If  he  happens  to  remember  a  pond  where  some  rare  species 
abounded  last  year,  let  him  not  again  turn  thither  in  search  of  it,  as  the 
chances  will  not  be  in  his  favour.  These  creatures  rarely  exist  in  the  same 
water  duiing  two  successive  years.  The  reasons  for  this  are  not  easily  ascer- 
tainable. The  remark  is  equally  applicable  to  Volvox  and  the  Desmidieac. 
The  search  will  be  most  productive  if  prosecuted  on  new  ground.  It  may  be 
remarked  that  the  Floscularian  Rotatoria  are  usually  discovered  accidentally, 
rather  than  by  predetermined  search.  Respecting  the  marine  Rotatoria  but 
little  is  known.  The  class  appears  to  have  but  few  representatives  in  salt 
water,  contrasted  with  their  abundance  elsewhere.  Nevertheless  some  may 
occasionally  be   observed  whilst  examining  corallines  and  seaweeds  under 


656  SYSTEMATIC  HISTOEY  OF  THE  INFrSORIA. 

the  microscope,  aroiind  which  objects  they  play  after  the  fashion  of  their 
freshwater  allies.  In  the  ocean  we  have  few  or  no  counterparts  of  the 
stagnant  pools  found  on  land ;  those  dark  holes  on  rocky  coasts,  the  homes  of 
the  Actinice  and  the  seaweeds,  which  would  otherwise  represent  ponds  and 
ditches,  are  too  constantly  distui'bed  by  the  tidal  wave  to  admit  of  the  accu- 
mulations of  decaying  vegetation  so  favourable  to  the  existence  of  the  fresh- 
water species. 

Classification". — The  exact  place  which  the  Rotatoria  should  occupy  in 
the  zoological  scale  is  as  yet  undetermined,  since  discordant  opinions  are 
entertained  on  the  subject  by  some  of  our  most  eminent  naturalists,  as  will 
be  seen  by  a  recurrence  to  Part  I.  of  this  work  (p.  392).  The  question  can 
be  decided  only  by  a  careful  study  of  their  development  as  compared  with  that 
of  other  animals.  Most  inferior  creatures  are  the  permanent  representatives 
of  conditions  which  are  merely  transitional  in  the  advance  from  the  ovum  to 
matmity  of  some  higher  form, — the  former  beings  obviously  occupying  a  posi- 
tion subordinate  to  the  latter,  inasmuch  as  they  never  advance  beyond  a  state 
which  only  occiu'S  in  the  higher  animal  in  its  immature  and  imperfect  con- 
dition. The  Myriapod  and  the  Worm,  with  theii^  strongly-marked  vegetative 
repetitions  of  parts,  obviously  find  a  temporary  representative  in  the  crawling 
caterpillar,  but  not  in  the  fully-formed  winged  insect  of  which  the  caterpillar 
is  but  the  rudimentary  larva.  Consequently  the  Worm  and  the  Myriapod 
must  alike  be  placed  below  the  Insect,  if  we  arrange  animal  forms  in  a  linear 
series  according  to  their  development.  Supposing  this  method  of  ascertaining 
the  true  zoological  position  of  any  class  of  animals  to  be  correct,  the  question 
naturally  arises,  what  larval  states  of  other  animals  are  most  closely  repre- 
sented by  the  permanent  forms  of  the  Rotifera  ?  It  is  clear  that  the  Eotifera 
have  little  afiinity  with  the  Polygastric  Infusoria  ;  for,  though  the  family  of 
Yorticellina  amongst  the  latter  animals  seems  to  constitute  a  sort  of  inos- 
culating link,  the  affinity  of  the  VorticeUce  to  the  Rotatoria  appears  to  be 
rather  one  of  resemblance  than  of  relationship.  The  history  of  the  VorticeUce^ 
as  worked  out  by  Professor  Stein,  reveals  morphological  changes  wholly  dis- 
similar from  what  occurs  in  the  Rotatoria,  amongst  which  the  encysting- 
process,  so  characteristic  of  the  VorticeUce-,  has  no  place.  This  process  is 
obviously  one  of  the  phenomena  of  development  by  gemmation  which  is  most 
prevalent  amongst  the  lower  animal  forms,  and  becomes  less  frequent  as  we 
ascend,  until,  amongst  the  higher  classes,  it  never  occurs.  In  ascertaining  the 
relation  of  the  Rotatoria  to  the  VorticeUce,,  it  is  necessary  to  inquii'e  how  far 
this  reproduction  by  gemmation,  as  distinct  from  sexual  reproduction,  has 
any  existence  amongst  the  former  animals  ;  and  this  is  precisely  the  question 
which  we  are  as  yet  unable  to  answer.  It  has  been  suggested  that,  of  the 
two  forms  of  eggs  known  to  be  produced  by  some  Rotatoria,  one  group  con- 
sists merely  of  buds  encased  in  a  shell,  whilst  the  others  are  the  tnie  sexual 
products ;  but  such  eminent  observers  as  Professor  Huxley  and  Dr.  Cohn  are 
at  issue  as  to  which  of  the  two  kinds  of  ova  are  to  be  respectively  regarded 
as  true  eggs  or  as  gemmae.  Dr.  Cohn  contends  that  the  bodies  ordinarily 
regarded  as  eggs  are  merely  gemmae  thrown  off  fi*om  the  organ  believed  to 
be  an  ovary,  \\athout  any  fertilization  by  a  male  animal, — thus  accounting 
for  the  extraordinary  profusion  in  which  these  eggs  are  developed,  whilst  so 
many  observers  have  been  baffled  in  their  attempts  to  discover  spermatozoa 
or  any  male  organization.  The  mode  of  development  which  Professor  Huxley 
observed  in  the  ova  of  Lacinularia,  and  Professor  Williamson  in  those  of 
Melicerta,  are  not  incompatible  with  the  idea  of  their  being  gemmae,  and 
the  ovary  a  gemmiferous  stolon.  Supposing  all  this  to  be  true,  we  have, 
in  the  formation  of  those  shelled  gommoc,  an  analogue  to  the  development  of 


OF  THE  llOTATOKIA.  657 

the  VorticeUa -hiids  from  the  Aciiietal  condition  of  the  Vortieelhe ;  but  the 
encysting  of  the  entire  body  of  the  latter  animal,  and  especially  its  resolution 
into  a  multitude  of  gemmules,  finds  no  parallel  amongst  the  liotifera ;  hence 
we  cannot  regard  the  two  classes  of  animals  as  having  any  close  affinity  to 
one  another. 

Professor  Owen  removes  the  Rotatoria  from  the  Cuvierian  group  of  Radiata 
and  places  them  amongst  the  Articulata,  in  close  alliance  with  the  Crustacea. 
This  idea  is  a  plausible  one,  and  has  several  supporters.  But  here  w^e  are 
met  by  the  fact  that  all  the  Crustacea,  not  excluding  the  Cirripeds  and  the 
Entomostraca,  pass  through  a  larval  condition,  resembling  which,  notwith- 
standing the  assertion  of  Leydig,  nothing  has  hitherto  been  observed  amongst 
the  Rotatoria  ;  whilst  the  latter  cannot  be  regarded  as  having  any  resemblance 
to  the  larval  conditions  of  these  higher  Crustaceans  in  any  stage  of  their 
histoiy.  Professor  Huxley's  suggestion,  that  they  are  the  permanent  repre- 
sentatives of  the  lam^al  forms  of  his  group  of  Annuloida  (including  the  Echi- 
noidea,  Annelida,  Trematoda,  and  Nematoidea),  appears  to  have  many  facts 
in  its  favoiu",  since  it  connects  them  with  the  articulate  division  of  animals 
without  raising  them  to  the  level  of  true  Crustaceans.  Burmeister  and  Leydig 
hold  similar  ^dews  to  those  of  Owen  respecting  the  close  relation  existing 
between  the  Rotatoria  and  the  Crustacea.  Leydig  dwells  especially  upon 
their  external  figure,  the  frequently  hardened  lorica,  the  existence  in  their 
bodies  of  striped  muscular  fibre,  their  nervous  system,  the  anatomical  and 
physiological  phenomena  of  their  sexual  life,  and,  lastly,  the  supposed  fact 
that  the  young,  at  its  liberation  from  the  o\*um,  has  not  the  form  of  the 
adult  animal,  and  consequently  must  undergo  a  metamorphosis.  These  argu- 
ments, when  examined  closely,  afford  feeble  support  to  Leydig's  opinion. 
External  form  is  an  unsafe  criterion  of  zoological  position.  Were  it  trust- 
worthy, it  would  bring  the  Rotatoria  nearer  to  the  cilio-brachiate  polypes 
than  to  the  Crustacea.  The  hardened  lorica  is  nothing  more  than  a  modified 
exo-skeleton,  which  is  as  fully  developed  in  the  Echinoderms  as  in  the 
Cmstaceans ;  whilst  in  the  majority  of  the  Lerneadse  (the  section  of  Crus- 
taceans to  which  Rotatoria  bear  the  closest  affinity)  this  hardened  integument 
is  wanting.  The  existence  of  striped  muscular  fibre  proves  nothing,  since 
Mr.  Busk  long  ago  discovered  this  structure  in  some  of  the  Acalephae,  The 
nervous  system  of  the  Rotatoria  is  as  yet  so  imperfectly  understood  that  little 
reliance  can  at  present  be  placed  upon  our  knowledge  of  it ;  besides  Avhich,  as 
Professor  Huxley  has  pointed  out,  a  similar  condition  to  that  of  the  supposed 
nervous  system  of  Rotatoria  exists  in  Turbellaria ;  and,  lastly,  the  pheno- 
mena of  sexual  life  amongst  the  Rotatoria  are  as  little  understood  as  is  their 
nervous  system.  The  few  instances  in  which  male  animals  have  been  found, 
present  some  resemblance  to  the  phenomena  seen  amongst  the  Lemeadie  ; 
but  the  subject  is  equally  involved  in  obscurity  in  each  of  the  two  classes  of 
creatures,  whilst  Leydig's  assertion,  that  the  young  Rotifera  undergo  meta- 
morphosis, appears  entirely  erroneous.  The  only  facts  positively  determined 
indicate  that  nothing  of  the  kind  takes  places  amongst  them,  whilst  all  the 
Crustaceans,  including  the  Lerneadse,  undergo  repeated  moults  before  reaching 
raatuiity. 

We  forbear  enlarging  on  this  question  of  the  zoological  position  of  the 
Rotatoria,  as  it  has  abeady  been  discussed  in  much  detail  in  the  first  part  of 
this  work  (p.  468  et  seq.). 

The  most  philosophical  mode  of  subdi\dding  the  Rotatoria  into  families 
is  almost  as  undetermined  as  their  zoological  affinities.  Ehrenberg,  who 
led  the  way  in  this  work  of  classification,  based  his  primary  groups 
upon  the  number  of  diAisions  and  form  of  the  ciliated  trochal  wreath,  sub- 


658  SYSTEMATIC  HISTORY  OY  THE  INFUSORIA. 

dividing  each  division  according  as  the  animals  composing  it  were  loricated 
or  illoricated. 

The  following  table  represents  his  classification : — 

Margin  of  ciliated  wreath  |  loricated    ...    Ichthydina. 

With  a  simple  continuous  ^  ^    "'[Loricated CEcistina. 

wreath  of  cilia  (Mono-  -{ 

trocha) Margin  of  ciliated  wreath  f  Illoricated   . . .    Megalotrochaea. 

lobed  or  notched  (Schi-  < 
^      zotrocha) [Loricated Flosculariaea. 

I'  With  the  ciliated  wreath  [  Illoricated   ...    Hydatincea. 
divided     into      several  < 

With  a  compound  or  di-  series  (Poly trocha) \  Loricated Euclilanidota. 

vided   wreath    of   cilia  ■{ 

(Sorotrocha)    With  the  ciliated  wreath  C  Illoricated    . . .    Pliilodinsea. 

I        divided  into  two  series  \ 

y       (Zygotrocha)   [  Loricated Brachionsea. 

N.B.  This  classification  is  given  more  at  length  at  p.  478. 

Siebold  adopts  the  classification  of  Ehrenberg  for  the  Eotatoria,  omitting  a 
few  genera.  Dujardin,  on  the  contrary,  regards  the  principles  employed  by 
the  great  Prussian  microscopist  in  framing  his  division  of  these  animals  as 
faulty  and  uncertain ;  consequently  he  puts  forth  a  classification  of  his  own, 
substituting  the  name  of  Systolides  for  the  better  known  one  of  Eotatoria. 
He  admits  four  primary  divisions  of  the  class,  viz. — 

1.  Those  Eotatoria  which  live  fixed  to  some  foreign  body  by  their  posterior 
extremity. 

2.  Those  which  employ  but  one  means  of  locomotion,  using  their  vibratile 
ciha  as  instruments,  and  being  always  swimmers. 

3.  Those  which  exhibit  two  modes  of  progression,  viz.  smmming  and 
crawling,  after  the  manner  of  leeches. 

4.  Those  which  creep  by  imcini,  and  are  destitute  of  vibratile  cilia. 

The  first  of  these  groups  includes  only  his  Flosculariens  and  Mehcertiens. 
The  second  contains  by  far  the  largest  number,  and  is  subdivided  into  two 
secondary  groups,  in  one  of  which  the  animals  have  an  integument  whoUy 
flexible,  whilst  in  the  other  they  have  some  part  of  it  solid,  constituting  a 
lorica  or  shield.  The  thii^d  section  contains  only  his  family  of  Eotifera, 
closely  corresponding  with  Ehrenberg's  family  of  Philodinaea ;  whilst  the  last 
comprehends  the  Tardigrada.  These  curious  animals  are  now  kno^Ti  to  have 
no  affinity  with  the  Eotatoria,  but  belong  to  the  Arachnida,  or  class  of  spiders. 
Indeed,  at  the  time  of  publishing  his  book,  Dujardin  expressed  doubts  as  to 
the  propriety  of  uniting  them  mth  the  Eotatoria. 

Leydig  proposes  a  new  classification  of  the  Eotatoria,  or  as  he  terms  them, 
in  accordance  with  his  views  respecting  their  nature,  Cilio-crustacea,  which 
he  arranges  "  according  to  their  fonns — whether  they  are  cyUndrico-conical, 
sacciform,  or  compressed,  together  with  which,  as  further  characters,  the 
condition,  presence,  or  absence  of  the  foot  may  be  employed." 

He  adopts  three  primary  divisions : — 

A.  Figure  between  clavate  and  cylindiical. 

B.  „       sacciform. 

C.  „       compressed. 


OF  THE  KOTATORIA.  •  659 

These  he  again  subdivides  as  follows : — 

1.  With  elongated,  transversely-ringed,  attached  foot. 

2.  With  elongated,  jointed  foot,  retractile,  like  a  telescope. 

3.  With  elongated,  jointed,  non -retractile  foot. 
A.<(  4.  With  short  foot  and  long  pedal  forceps. 

o.  With  short  foot  and  pedal  forceps  which  are  of  equal  length  with,  or 

somewhat  shorter  or  longer  than  the  foot. 
6.  Without  foot. 


B. 


1.  Foot  short. 

2.  Foot  absent. 


p    J  rt.  Depressed  from  above  downwards  ]  o"  -p    f.    -k      *■' 
[  b.  Laterally  compressed. 

It  will  be  seen  that  the  classifications  of  Ehrenberg,  Dujardin,  and  Ley  dig 
agree  in  one  featui'e  :  they  are  more  or  less  artificial,  being  based  upon 
peculiarities  of  external  fonn  and  habit  rather  than  upon  internal  organiza- 
tion. The  subdivision  of  the  trochal  wreath  varies  in  its  extent  with  the 
age  of  the  animal,  the  depth  of  its  sulci  increasing  with  the  approach  of 
maturity ;  consequently  the  defectiveness  of  Ehrenberg's  system  becomes  at 
once  obvious.  No  such  changes  as  we  have  just  referred  to  afi'ect  the  internal 
viscera,  except  in  a  minute  degree  ;  consequently  the  latter  alone,  when 
thoroughly  understood,  can  furnish  the  true  materials  for  a  philosophical 
classification.  But  unfortunately  we  do  not  as  yet  possess  such  a  number  of 
accurate  observations  as  admit  of  our  arranging  the  various  species  on  this 
higher  basis.  For  example,  the  Rotatoria  are  either  monoecious  or  dioecious : 
a  few  have  been  demonstrated  to  belong  to  the  latter  class ;  but  of  the  vast 
majority  we  are  unable  to  say  which  of  these  two  features  characterizes 
them.  The  belief  in  their  monoecious  natui^e  has  until  recently  been  general ; 
but  the  possibility  of  their  being  all  dioecious  now  suggests  itself.  Should 
future  observations  establish  the  fact  of  some  Rotatoria  being  monoecious 
and  others  dioecious,  the  distinction  will  be  one  of  paramount  importance 
as  a  basis  of  classification.  But  of  the  internal  organization  of  the  vast 
majority  of  these  animals  we  unfortunately  know  little  or  nothing.  A 
very  small  number  even  of  the  higher  forms  have  been  submitted  to  rigid 
and  accurate  scrutiny;  consequently  the  want  of  material  for  a  natural 
classification,  based  on  anatomical  and  physiological  data,  compels  us  to  fall 
back  upon  such  as  are  artificial.  (See  Part  I.  p.  477  for  additional  remarks 
on  classification.) 

The  relative  value  of  the  three  systems  of  Ehrenberg,  Dujardin,  and  Leydig 
will  be  a  disputed  question.  A\Tiere  the  pui-pose  to  be  accomplished  is  merely 
the  provision  of  an  index  (and  artificial  systems  can  be  little  more),  the  clas- 
sification in  which  the  distinctions  are  most  readily  recognized  will  best  fulfil 
its  purpose.  On  these  grounds  we  think  there  is  little  room  for  choice  be- 
tween those  of  Ehrenberg  and  Dujardin.  The  two  primarj^  sections  of  the 
great  Prussian  natiu-alist  are  easily  recognized,  his  four  principal  subdivisions 
almost  equally  so ;  and  the  ultimate  division  of  each  group  into  a  loricated 
and  an  illoricated  series  not  only  facilitates  the  investigations  of  the  young 
student,  but  is  an  element  in  Dujardin's  system,  who,  by  adopting  it,  re- 
cognizes its  value.  At  finest  sight  Leydig's  classification  would  appear  to 
approach  nearer  to  a  natural  system  than  either  of  the  others  enumerated ; 
but  close  examination  does  not  confii^m  this  impression,  since,  in  order  to 
arrange  the  objects  in  their  respective  groups,  such  genera  as  Diglena,  Far^ 

2u2 


660  SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 

crdaria,  and  Notommata  have  required  to  be  subdivided,  part  being  thi'own 
into  one  subdivision  and  part  into  another.  Objects  which  present  such  close 
resemblance  as  to  be  capable  of  arrangement  in  one  generic  group  can  scarcely 
be  so  diverse  as  to  justify  their  separation  into  different  families.  The  de- 
tachment of  the  fifth  section  from  the  fourth,  merely  because  its  individuals 
are  furnished  mth  short  pedal  forceps,  would  furnish  a  precedent  for  classi- 
fying birds  and  quadrupeds  according  as  they  have  long  tails  or  short  ones. 
These  reasons  have  led  us  to  retain  the  classification  of  Ehrenberg  for  the 
present,  since  the  advantages  afforded  by  the  two  newer  systems  do  not  seem 
sufiiciently  great  to  justify  our  abandoning  the  general  plan  followed  in  the 
previous  editions  of  this  work.  At  the  same  time  we  are  fully  ahve  to  its 
imperfections,  both  in  its  principles  and  details.  Leydig's  objection  to  Ehren- 
berg's  employment  of  the  term  lorica  is  a  substantial  one,  since  it  is  stretching 
the  term  beyond  what  is  admissible,  to  apply  it  to  the  delicate  investing 
membranes  of  Floscularia  and  StepTianoceros,  or  to  the  gelatinous  envelope  of 
Conochilus.  Consequently,  though  for  reasons  already  advanced  we  retain 
the  subdivisions  of  the  Prussian  microscopist,  we  extend  his  definitions  of  his 
third  series  of  groups :  instead  of  defining  them  as"  loricated,''^  and  "illoricated," 
we  would  describe  them  as  '^loricated,  or  usually  provided  with  a  hard 
investing  layer,"  and  ''  illoricated,  or  unprovided  with  a  hardened  investing 
layer." 

Leydig's  objection,  that  such  animals  as  Ehrenberg  indicates  by  the  terms 
Polytrocha  and  Zygotrocha  have  no  existence,  is  ill  founded.  There  is  no 
question  that  the  ciliated  lobes  of  the  head  are  divisible  and  distinct  in  a 
large  number  of  species  ;  and  being  so,  they  become  as  good  characteristics  of 
families  as  do  Leydig's  long  or  short  pincers  to  the  foot. 


FAMILY  I.— ICHTHYDINA. 

Kotatoria  with  a  single  continuous  rotary  organ,  not  cut  or  lobed  at  the 
margin ;  destitute  of  lorica  or  indm-ated  integument.  In  Ftijgura  and  Qh- 
nopliora  the  wheel-like  organ  is  in  the  form  of  a  cii^le,  and  is  an  instrument 
of  locomotion.  In  the  other  genera  it  is  long  eUiptical,  and  on  the  ventral 
surface.  Chcetonohis  and  Ichthydmm  have  each  a  forked  foot-like  process, 
and  the  rest  of  the  genera  a  simple  one.  A  long  simple  alimentaiy  canal, 
with  a  long  oesophagus,  apparently  without  teeth,  occiu's  in  Ohcetonotm  and 
Ichihydium.  Glenophora  has  a  short  oesophagus,  with  two  single  teeth  ;  and 
Ptygura  an  elongated  stomach  and  three  teeth.  Glands  are  seen  only  in 
Chcetonotus  and  Ptygura.  No  caeca  exist  in  any  of  the  genera.  The  male 
reproductive  organs,  not  hitherto  discovered ;  those  of  the  female  consist,  in 
Ptygura  and  Iclithydium,  of  a  large  ovarium  containing  one  or  more  developed 
ova.  The  two  red  eyes  seen  in  GlenopJiora  are  supposed  by  some  to  indicate 
the  existence  of  a  nervous  system  as  yet  undiscovered. 

Ehrenberg's  classification  of  this  family  will  be  found  in  p.  478  of  the 
General  History.  It  is  probably  the  weakest  which  Ehrenberg  has  esta- 
blished, being  admitted  neither  by  Dujardin  nor  Leydig.  Dujardin  does  not 
recognize  the  genus  Glenophora,  neither  does  Siebold,  whilst  Leydig  rejects 
both  it  and  Ptygura,  regarding  them  as  immature  forms  of  some  other 
species.  Ptygura  especially,  the  latter  writer  suggests,  may  be  the  young 
MeUcerta  rhigens ;  but  this  idea  Professor  AVilliamson's  obsei-vations  have 
shown  to  be  erroneous  ;  consequently  the  genus  must  be  retained  until  its 
immature  condition  is  better  established  than  at  present.  Dujardin  com- 
prehends Ptygura  in  his  family  of  Mclicertiens,  whilst  he  rejects  Ichthydium 


OF  THE  ICHTHYDIXA. 


661 


and  Chcetonotus  from  amongst  the  Eotatoria,  believing  them  to  be  Polygastric 
Infusoria, — a  conclusion  with  which  we  are  strongly  disposed  to  agree. 

Genus  PTYGURA. — Eyes  and  hair  absent ;  foot  simjDle,  truncated,  cylin- 
drical. Body  camiDanulate,  oblong.  Eotary  organ  simple,  and  nearly  circular. 
Numerous  tooth- like  bodies,  adhering  to  the  bulb  of  the  oesophagus,  two 
glands,  a  small  narrow  oesophagus,  an  elongated  stomach,  and  a  subgiobular 
rectum  constitute  the  apparatus  of  nutrition.  An  ovarium  and  a  contractile 
vesicle  have  been  observed,  but  no  visual  organs. 

This  genus  is  comprehended  in  the  family  Melicertiens  of  Dujardin,  along 
with  Ladmdcu'ia,  Tuhicolaria,  and  Melicerta,  and  is  made  to  include  the 
species  distributed  by  Ehrenberg  in  the  several  genera  Ptygura,  (Ecistes,  and 
Conochilus ;  for  Dujardin  states  that  the  individuals  of  these  three  genera 
present  no  further  difference  than  is  seen  in  the  gelatinous  envelope,  which 
surrounds  the  two  last,  forming  in  (Ecistes  a  distinct  tube  for  each  individual, 
whilst  it  inchides  the  individuals  of  Conochilus  in  a  common  globular  mass, 
and  is  absent  in  Ptygura.  The  same  author  would  name  (Ecistes  crystallinus 
"  Ptygura  crystaUina/'  and  the  Volvox  conockila  "  Ptygura  Volvox." 


Ptygura  Melicerta.  —  Transparent ; 
body  cylindrical,  club-shaped,  tm-gid  an- 
teriorly, with  two  little  curved  horns  at 
the  mouth,  and  a  single  short  tube  at 
the  neck  (?).  The  tail-like  foot  always 
remains  transversely  folded  (wrinkled), 
as  seen  in  xxv.  354,  which  represents 


the  imder  side.  When  swimming,  a  ring- 
like simple  vibratile  organ  is  thrust  out, 
with  a  lateral  notch.  The  two  jaw-like 
parts  of  the  oesophageal  bulb  have  nu- 
merous teeth,  as  represented  at  xxv.  355. 
1-140". 


Genus  DASYDYTES  (Gossc). — Eyes  absent;  body  furnished  with  bristle - 
hke  hairs  ;  tail  simple,  truncate. 

This  genus,  according  to  Ehrenberg's  description  of  Ichthydina,  must  follow 
after  Ptygura. 


Dasydytes  goniothrix. — Hairs  long, 
each  hair  bent  with  an  abrupt  angle ; 
neck  constricted.  1-146".  Found  at 
Leamington. 

D.  antenniger. — Hair  short,  downy;  a 


pencil  of  long  hairs  at  each  angle  of  the 
posterior  extremity  of  the  body ;  head 
furnished  with  two  club-shaped  organs 
resembling  antennge.     1-170". 


Genus  ICHTHYDIUM.— Tail  cleft  or  forked,  foot-like ;  no  eyes  or  hair ; 
currents  at  the  mouth  and  along  the  ventral  side  indicate  the  existence  of  a 
\-ibratile  organ,  which  not  only  serves  for  swimming  but  likewise  for  creeping. 
A  long  oesophagus,  a  thick  simple  conical  alimentary  canal,  and  sometimes  a 
large  single  o\^im,  comprise  our  knowledge  of  their  organization.  It  is  pro- 
bable that  a  cylinder  of  little  wand-Uke  teeth  exists  (see  Part  I.  p.  380). 


ICHTHYDIUM  Poclura  (  CercariaPodura, 
M.).  —  Straight,  oblong,  often  slightly 
constricted  anteriorly,  where  it  is  turgid, 
and  sometimes  three-lobed.  It  is  colour- 
less or  whitish,  but  during  repletion 
sometimes  appears  yellowish  ;  the  ven- 
tral surface  is  Hat  and  ciliated,  the  dorsal 


arched  and  smooth.  The  large  dark 
ovarium  has  been  seen  by  Ehrenberg. 
It  seldom  swims,  but  mostly  creeps. 
xxv.  356  exhibits  a  fidl-grown  animal- 
cule (ventral  side).  Among  Confervas 
and  OsciUatorige.    1-440"  to  1-140". 


Genus  CH^TONOTUS.— Dorsal  surface  covered  with  hairs ;  tail  forked  ; 
eyes  absent.  Locomotion  is  performed  by  means  of  a  double  row  of  ciha  upon 
the  ventral  surface,  forming  a  band-like  rotary  organ.  The  nutritive  organs 
consist  of  a  tubular  mouth,  probably  provided  with  a  cylinder  of  teeth,  a  long 
thin  oesophagus,  and  a  long  conical  stomach  (trachchgastricum),  upon  whose 


662 


SYSTEMATIC  HISTORY  OF  THE  rNTUSORIA. 


upper  thick  end  (in  the  large  species)  two  semiglobular  glands  are  seen  ;  at 
certain  periods  from  one  to  three  large  ova  are  formed  posteriorly,  but  the 
ovarium  in  which  they  are  developed  has  not  been  directly  observed ;  male 
reproductive  organs  unknown.  They  are  sluggish  in  their  movements,  except 
in  creeping;  they  rarely  swim.    (See  Part  I.  p.  380  et  seq.) 

berg  has  seen  only  one  large  o\Tim ;  he 


Cils:tonotus  maximiis  (xxxi.  29, 30). 
— Elongated,  slightly  constricted  ante- 
riorly, tui'gid  and  obtusely  three-lobed ; 
hairs  upon  the  back  short  and  equal. 
From  his  latest  observ-ations,  Elirenberg 
states  the  mouth  to  possess  teeth,  of 
which  he  has  counted  more  than  eight ; 
he  once  saw  the  exclusion  of  ova  imme- 
diately over  the  foot-like  tail.  It  creeps 
but  slowly.  1-216"  to  1-120".  (See 
p.  381.) 

C.  Larus  (Trichoda  Acarus,  Anas  et 
LaruSy  M.). — Elongated,  slightly  con- 
stricted anteriorly,  where  it  is  turgid  and 
obtusely  triangular;  the  posterior  han 
on  the  dorsal  surface  is  long-est.    Ehren- 


states  that  the  bodies  of  those  bearing 
ova  were  thick  posteriori}^,  though,  under 
other  circumstances,  the  head  is  broadest. 
It  appears  to  have  eight  teeth.  The  dor- 
sal hairs,  which  are  arranged  in  longi- 
tudinal rows,  destroy  the  transparency 
of  the  body.  xxv.  357  is  a  dorsal,  and 
358  a  side  view.  Ova  one-third  the 
length  of  the  body.  In  muddy  water. 
1-720". 

C.  hrevis. — Ovato-oblong,  slightly  con- 
stricted near  the  turgid  front;  dorsal 
hairs  few,  the  posterior  longest ;  ova 
small.     1-340". 


As  before  stated,  Dujardin  places  this  genus,  together  with  Ichthydium, 
among  the  Infusoria  (Polygastrica,  Elir.),  but  in  a  subclass  of  them,  called 
symmetrical,  along  with  Coleps  and  a  doubtful  genus  named  Planariola. 
These  genera  are  distinguished  by  him  from  all  other  Infusoria  in  baring  a 
symmetrical  figure. 

One  species  of  Chcetonotus  described  by  Dujardin  is  probably  new,  although 
it  may  be,  as  he  remarks,  but  the  C.  maximus  of  Ehrenberg. 

The  following  are  its  characters : — 


C.  squamatus. — Elongate,  narrowed  at 
its  anterior  third,  but  expanded  in  its 
posterior  half.  1-130"  to  1-135".  Co- 
vered with  short  hairs,  which  are  dilated 


in  a  scale-like  form  toward  the  base,  and 
regularly  imbricated.  In  long-kept  sea- 
water  brought  from  Toulouse. 


Genus  SACCULUS  (Gosse)  (XL.  17,  18).— One  eye,  frontal;  body  desti- 
tute of  hair,  and  without  a  foot ;  rotaiy  organ  a  simple  wi'eath  ;  alimentary 
canal  very  large ;  jaws  set  far  forward,  apparently  consisting  of  two  dehcate 
unequal  mallei  and  a  slender  incus ;  very  evanescent ;  eggs  attached  behind 
after  deposition. 

This  genus  comes  nearest  to  GlenojyJwra,  but,  luilike  the  latter,  has  but 
one  eye.     Forty's  genus  Ascomorpha  appears  identical  with  Saccidus. 

Sacculus  viridis. — Pear-shaped ;  flat- 
tened  ventrallv,  the   anterior   end   the 


nari'ower ;  head  conical-pointed,  sur- 
rounded by  a  ^\Teath  of  long  cilia ;  di- 
gestive canal  occupying  nearly  the  whole 
body,  and  alwa3^s  filled  with  a  substance 
of  a  rich  green  hue  in  masses.  1-150". 
This  curious  animal,  found  in  consider- 
able number  in  a  little  pool  on  Ilamp- 
stead   Heath,   must  be  placed  in   this 


family,  according  to  Ehrenberg's  system ; 
but  the  mode  of  carrying  its  eggs  indi- 
cates an  afiinity  with  the  Brachionaea. 
The  AscomorpJia  gcfnamca  of  Leydig  is 
identical  with  the  above  species. 

Mr.  Gosse  has  ascertained  that  this 
species  is  dicecious.  XL.  17  represents 
a  newly-born  male,  and  18  a  female  with 
ova  attached. 


Genus  GLENOPHOEA (XXV. 359).— Eyes  two, placed  anteriorly;  rotary 
organ  frontal,  circular  ;  tail  bifid,  truncated.  The  alimentary  canal  is  short, 
thick,  and  conical ;  it  sometimes  contains  green  matter.  The  two  protruding 
forceps-like  bodies  in  the  middle  of  the  rotary  organ  may,  says  Ehrenberg, 


OF  THE  (ECISTINA. 


663 


be  considered  teeth ;  glands  are  indicated  by  knot-like  turbid  bodies.  The 
eyes  are  sharply  circumscribed,  and  situated  at  the  frontal  region.  Dujardin 
and  Leydig  believe  this  genus  to  h%  based  on  young  animals,  and  as  such 
unsatisfactory. 


Glenophora  Trochus.  — Ovato-coni- 
cal,  truncated  and  turgid  anteriorly,  at- 
tenuated posteriorly,  ^\dth  a  false  foot ; 
the  eyes  are  blackish.  It  swdms  quickly, 
like  a  Trichoda  or  free  Vorticella.     The 


genera  Monolahis  and  Microcodon  have 
similar  forms,  (xxv.  359,  360  represent 
two  animalcules,  the  latter  havmg  the 
stomach  filled  with  a  gi-een  substance.) 
1-570". 


FAMILY  II.— (ECISTINA. 

Rotatoria  with  a  single  rotary  organ,  entire  at  the  margin,  and  an  ex- 
ternal gelatinous  envelope.  This  family  contains  only  two  genera,  which 
possess  a  more  developed  internal  organization  than  any  hitherto  described. 
They  are  further  provided,  according  to  Ehrenberg,  with  locomotive  organs, 
internal  muscular  bands,  a  tail- like  foot  without  terminal  pincers ;  nutritive 
organs,  among  which  is  a  crushing  apparatus  consisting  of  teeth  in  rows ; 
two  pancreatic  glands,  and  red  visual  or  eye- spots.  In  Conochilus  alone  he 
thinks  he  observed  ganglia  with  nervous  fibrillae,  male  organs,  vessels,  and 
two  filiform  tremulous  organs  or  gills. 

This  description  is  of  course  modified  by  the  views  Ehrenberg  entertains 
respecting  the  various  organs  contained  in  the  bodies  of  these  animals.  We 
have  no  evidence  that  the  glands  are  pancreatic  ;  the  "  male  organs  "  are 
the  w^ater-vascular  canals  of  other  writers,  of  which  the  tremulous  organs  or 
giUs  are  external  appendages;  the  "vessels"  are  muscular  bands;  and  the 
nervous  fibrillae  and  ganglia  have  a  more  than  doubtful  existence. 

{Special  for  each  animalcule  CEcistes. 
Compound,  or  common  to  many  animalcules Conocliilua. 


Both  the  (Ecistes  and  Conochilus  are  included  by  Leydig  in  his  first  division 
of  Rotatorial  animals. 

Genus  (ECISTES  (XXV.  361-364).— Characterized  by  each  animalcule 
ha\dng  a  separate  lorica.  The  two  eyes,  situated  anteriorly,  become  eflPaced 
as  age  advances.  Ciliary  wreath  simple  and  frontal ;  the  long  tail-like  foot 
has  internal  longitudinal  muscles.  Alimentary  canal  simple,  tubular,  con- 
tracted ;  stomach  elongated ;  teeth  attached  in  rows  to  two  jaws  situated  in 
the  pharyngeal  bulb,  and  two  glands,  compose  the  apparatus  of  nutrition. 
The  visual  organs  are  red  when  the  animalcule  is  yoimg,  and  colourless  in 
old  age.  The  ovarium  has  only  a  single  ovum.  The  envelope  is  a  viscid, 
gelatinous,  cylindiical  sheath  (urceolus),  into  which  the  animalcule  can 
entirely  withdraw  itself,  or  which  it  may  quit  when  a  new  one  is  desirable. 
The  attachment  to  the  bottom  of  the  lorica  is  by  the  under  surface  of  the  end 
of  the  foot-like  tail. 

(Ecistes  crystallimis.  —  Lorica  hj^a- 
line,  viscid,  floccose ;  body  crystalline. 
The  structure  it  is  difficult  to  see.  Each 
jaw  has  three  distinct  teeth.  The  de- 
velopment of  the  young  from  the  egg 
is  interesting  to  observe  :  Ehrenberg 
saw  within  the  shell  two  dark  points 
(eyes)  near  the  already  developed  jaws  -, 


and  on  giving  the  egg  a  gentle  pressm'e 
it  burst,  and  the  free  young  animal 
came  forth  (xxv.  361,  a  full-grown  ani- 
malcule in  the  act  of  unfolding  itself; 
362,  another  with  its  rotaiy  organ  ex- 
panded). Their  sheaths  are  incrusted, 
and  within  may  be  seen  a  number  of 
eggs  (363,  364  represent  them  attached 


664 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


to  the  pectinated  leaves  of  the  water-  j  pocket  magniher).     Length,   with  tail, 
violet,  as  they  appear  under  a  shallow  |  1-tiG" ;  without,  1-140" ;  lorica  1-70". 

Geniis  CONOCHILUS  (XXY.  365-370).— Animalcules  social,  ha\dng  con- 
glomerate and  contiguous  envelopes ;  each  has  two  permanent  eyes.  Only 
one  species  is  kno^vn;  its  description,  therefore,  wiU  include  that  of  the 
genus. 


CoNOCHiLus  Volrox. — The  compound 
masses  w^hite  ;  envelope  gelatinous,  hya- 
line, consisting  of  from  ten  to  forty  ani- 
malcules united  so  as  to  form  a  sphere, 
which  revolves  in  swimming,  like  the 
Voli'ox.  The  frontal  region  of  the  ani- 
malcule is  broad,  trimcated,  and  sur- 
romided  wdth  a  wreath  of  cilia,  inter- 
rupted at  the  mouth,  w^hich  is  lateral. 
On  the  frontal  plane  arise  four  thick 
conical  papilla?,  often  furnished  ^^'ith  an 


ing  thickened  and  bent.  (In  the  group, 
XXV.  365-368,  the  lorica  is  not  sho^NTi.) 
There  are  no  anterior  muscles,  but  three 
pairs  of  posterior  ones,  which  disappear 
near  the  rotary  organ  ;  there  are  also  a 
back  and  two  lateral  pairs.  Several 
transverse  bands  appear  connected  with 
two  anterior,  lateral,  longitudinal  ones, 
which,  Ehrenberg  states,  must  arise  from 
a  netw^ork  near  the  head,  as  in  Hijdatina. 
These  are  probably  muscular.     He  has 


anterior,  as  seen  in  xxv.  365,  366,  and 
368.  The  oesophagus  is  short  and  nar- 
row; its  head,  or  bulb,  has  jaws,  w^th 
teeth  and  four  muscles;  it  lies  imme- 
diately within  the  mouth.  The  stomach 
and  rectum  are  oval.  Tw^o  spherical 
glands  are  observed  near  the  oesophagus, 
and  posteriorly  an  ovaiiiun,  often  con- 
taining a  large  ovum,  w^hich  is  expelled 
near  the  base  of  the  tail.  The  ovate  or 
shortly-cylindrical  body  terminates  in  a 
long,  thin,  and  strong  cylindrical  foot- 
like tail,  the  end  having  a  suction-disc. 
The  gelatinous  envelope  is  only  percep- 
tible in  coloured  water,  except  when 
infested  with  green  parasitical  Monads ; 
the  animalcules  can  completely  withdraw 
themselves  wdthin  it,  their  tails  becom- 


articulated   bristle,    especially   the   two  j  also  seen  two  spiral  bands,  situated  poS' 

teriorly.  Two  beautiful  red  visual  organs 
lie  immediately  beneath  the  wreath  of 
cilia,  and  behind  them  little  oval  bodies, 
w^hich  he  regarded  as  nervous  ganglia, 
but  doubtless  erroneously.  In  the  foot- 
like tail  are  two  large  w^edge-shaped 
glands,  probably  male  organs.  These 
creatures  will  feed  upon  cannine  and 
indigo,  but  are  mostly  filled  with  a 
golden-coloured  food.  (xxv.  370  repre- 
sents a  cluster  of  animalcules  magnified 
about  ten  diameters,  of  which  figs.  365- 
368  represent  a  portion  highly  mag- 
nified; the  first  is  an  under  view,  the 
two  next  dorsal  views,  and  the  last  a 
side  view.  xxv.  369  sliow^s  the  jaws, 
teeth,  and  part  of  the  pharyngeal  bulb 
separate.)     Size  1-60";  sphere  1-9". 


FAMILY  III.— MEGALOTROCH^A. 

No  envelope  or  lorica.  Rotary  organ,  w^hich  is  also  that  of  locomotion, 
simple,  incised  or  flexuose  at  the  margin.  Distant  muscular  bands  visible, 
by  means  of  which  the  shape  of  the  body  can  be  modified.  In  Megcdotroclia 
the  alimentary  canal  is  provided  with  two  jaw^s,  a  stomach,  two  caeca,  and 
tw^o  glandular  appendages.  In  Microcodon  there  are  two  single-toothed  jaws, 
and  a  simple  canal,  without  distinct  stomach  or  cteca.  The  ovarium  in  both 
genera  develope  a  few  large  ova,  each  of  which  in  Megalotrocha,  Ehrenberg 
afiirms,  after  expression,  is  retained  in  connexion  with  the  body  by  means  of 
a  thread.  Water-vascular  canals,  with  tremulous  tags,  exist  in  Megcdotroclia  ; 
red  eye-spots  in  both  genera  indicate  a  nervous  system ;  and  in  Megalotrocha 
a  radiating  body,  supposed  to  be  a  cerebral  ganglion  and  to  fonn  dark  glan- 
dular (?)  spheres,  are  seen  in  the  neighboui'hood  of  the  mouth. 

Ehrenberg's  divisions  of  the  family  are  given  at  p.  478  of  the  General 
History. 

The  genera  contained  in  this  family  ai'e  undescribed  by  Dujardin  and 
Leydig,  whilst  Siebold  only  recognizes  Megalotrocha .  Cuphonautes,  instituted 
by  Ehi-enberg  upon  two  animalcules  found  in  water  from  the  Baltic,  Dujardin 


OF  THE  FLOSCVLATII.EA. 


GGo 


considers  is  a  doubtful  member  of  the  llotatorial  class ;  and  Leydig  suggests 
that  it  is  probably  a  larva  of  some  cephalous  mollusk.  In  the  propriety  of 
excluding  it  from  amongst  the  Eotatoria  we  fully  concur.  Dujardin  and 
Leydig  also  transfer  Microcodoyi  to  another  family,  regarding  its  caudal  process 
as  being  a  free  articulate  foot  rather  than  a  contractile  attached  peduncle. 
Its  affinities  are  unquestionably  with  Furcularia,  Notommata,  and  Hydatina, 
rather  than  with  Megalotrocha. 

Ehrenberg's  description  of  the  ovum  of  Megalotrocha  alho-fiavicans  con- 
tains some  grave  errors.  He  describes  the  embryo  as  developing  within  the 
germinal  vesicle,  and  growing  at  the  expense  of  the  surrounding  yelk,  as  is 
the  case  with  a  vertebrate  ovum.  This  is  so  contrary  to  what  occurs  in 
other  Kotifcra,  in  which  the  entire  yelk  is  directly  transmitted  into  the 
embryo,  that,  merely  reasoning  from  analogy,  we  should  be  led  to  reject  it. 
But  Kolliker  has  shown  that  the  embryo  of  Megalotrocha  is  developed  in  the 
same  way  as  those  of  other  Rotifera. 

Genus  MICROCODON. — Eye  single ;  wreath  of  cilia  simple,  bent  in  the 
middle  so  as  to  resemble  the  figure  8  lying  transversely ;  alimentary  canal 
thick  and  straight,  without  a  stomach ;  no  oesophageal  tube,  but  a  sort  of 
pharyngeal  bulb  and  a  couple  of  single-toothed  jaws ;  also  a  turgid  ovarium. 
Immediately  behind  the  rotary  apparatus  is  a  small  red  visual  organ ;  and  at 
the  frontal  region,  beside  it,  is  a  reddish  knot  whose  function  is  unknown. 


MiCROCODON  Clavus.  —  Campanulate, 

{)edicled,  the  styliform  foot-like  tail  as 
ong  as  the  body ;  in  the  middle  of  the 
brow  are  two  bimdles  of  stiff  bristles : 
two  pincer-like  points,  evidently  teeth, 
project  out  of  the  middle  of  the  rotaiy 


organ,  and  are  in  connexion  with  the 
reddish  jaws,  (xxxii.  371  is  a  back,  and 
fig.  372  a  left  side  view.)     1-280". 

Perty  thinks  that  the  so-called  eye 
consists  of  two  red  stripes,  beneath  which 
a  ribbed  body  is  faintly  discernible. 


Genus  MEGALOTROCHA. — Eyes  two,  sometimes  becoming  effaced  by 
age ;  rotary  organ  has  two  lappets.  The  nutritive  system  consists  of  a 
stomach,  caecum,  rectum,  and  oesophageal  head,  having  two  jaws,  Avith  teeth, 
and  two  glands ;  reproductive  organs,  a  short  knotted  ovarium,  with  a  few 
ova ;  muscles,  three  pair  anterior,  two  pair  posterior,  longitudinal ;  two  con- 
tractile muscles  for  the  rotary  organ,  and  four  oesophageal ;  eyes  frontal,  of 
a  red  colour  when  young ;  four  circular  transverse  muscular  bands  are  also 
seen.  The  nature  of  four  opaque  white  spherical  bodies  at  the  base  of  the 
rotary  organ  is  unknown. 

MEGALOTnocHA  alho-flavicans  ( Vor-  \  or  five  thus  attached,  and  in  process 
ticella  socialis,  M.).  —  White  and  free  !  of  further  development,  (xxxii.  374- 
when  young ;  yellowish,  and  attached  in  376  represent  difterent  specimens  ;  377 
radiating  clusters  when  old.  Ehrenberg  merely  the  teeth  and  jaws  separate.) 
states  he  has  often  perceived  the  red  ITpon  M^ater-plants.  Size  of  single  ani- 
e3^es  within  the  unbroken  egg ;  and  the  I  malcule  1-36"  ;  of  the  spheres  1-6" 
jaws,  as  if  in  the  act  of  chewing,  move  j  (xxiii.  1). 

laterally  and  horizontally  against  eacli        M.  vehda  (Gosse). — Animals  separate ; 
other.     Two  ova  are  rarely  produced  at    disc  partially  enveloped  in  a  cleft,  gra- 
one  time ;  the  egg,  when  expelled  from  !  niilar  integument ;  eggs  not  attached  to 
the  body,  remains  attached  to  it  by  a    the  parent  after  deposition.     1-55". 
thread ;  and  the  parent  lias  often  four  | 


FAMILY  lY.— FLOSCULARI^A. 

Ilotatoria  surrounded  by  a  case  or  envelope,  and  provided  with  a  single 
rotary  organ,  flexuose  at  its  margin  and  lobed  or  divided,  having  from  two  to 


6Q(5  SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 

six  clefts.  In  some  genera  the  cilia  of  this  organ  are  quiescent  at  intervals, 
not  vibrating  continuously ;  the  alimentary  canal  is  complex,  usually  divided 
transversely  into  several  segments,  and  with  various  external  appendages, 
believed  to  be  glandular,  the  proventricular  segment,  gizzard,  or  pharyngeal 
bulb  furnished  with  teeth.  Lacinularia  has  a  mouth,  oesophagus,  pharyngeal 
bulb  with  teeth,  a  stomach  constricted  into  three  segments,  and  a  short 
intestine  ;  the  lower  stomach  clothed  internally  with  a  very  long  ciha. 
Melicerta  has  a  similar  arrangement,  but  with  only  two  unequal  segments  in 
the  stomach,  both  of  which  are  ciliated  interiorly.  Two  water-vascular 
canals  arise  from  a  contractile  sac  opening  into  the  cloaca,  and  pass  upwards, 
one  on  each  side  of  the  alimentary  canal  to  the  head,  where,  in  Lacinularia , 
they  ramify  into  a  network ;  along  their  course  they  have  appended  to  them 
small  tags  or  sacs,  each  containing  a  large  vibratile  cilium.  These  have  been 
seen  in  Lacinularia,  Melicerta,  and  Stephanoceros.  In  Lacinularia,  Limnias, 
and  Melicerta,  a  small  lobate  mass  exists  near  the  mouth,  believed  by  Huxley 
to  be  a  cerebral  ganglion.  Leydig  assigns  nervous  functions  to  small  bodies 
distributed  through  Lacinularia ;  but  these  appear  to  be  merely  the  smaU 
stellate  masses  of  viscid  protoplasm  described  by  WiUiamson  in  Melicerta, 
and  Leydig  in  Stephanoceros.  Eyes  exist  in  all  the  genera,  except  Tuhico- 
laria,  at  some  stage  of  life.  In  Melicerta  and  Lacinularia  they  disappear  as 
the  animal  approaches  adult  life.  Gosse  says  that  the  same  is  usually  the 
case  in  Floscularia,  but  that  he  has  occasionally  met  with  adult  specimens  in 
which  eyes  were  present.  Some  species  (if  not  all)  have  well-marked  fasciculi 
of  voluntary  muscular  fibre,  especially  running  parallel  to  the  long  axis  of 
the  body,  which  their  contraction  shortens.  Male  reproductive  organs  hitherto 
unobserved.  Female  organs  an  ovisac  composed  of  thin  transparent  mem- 
brane, distended  with  granular  protoplasm,  in  which  are  distributed  cells  or 
germinal  vesicles,  each  containing  a  nucleus  or  germinal  spot.  In  Melicerta 
this  ovarium  communicates  with  the  cloaca  by  means  of  an  oviduct.  Some 
species  produce  two  classes  of  eggs,  one  being  probably  the  true  o\Tim,  the 
other  an  encased  gemma  or  bud.  Several  species  retain  the  eggs  within  the 
envelope  of  the  parent  until  the  young  are  hatched ;  others  set  them  free  at 
an  early  stage  of  embryonic  development. 

Ehrenberg's  arrangement  of  the  genera  of  this  family  wUl  be  found  at 
p.  478  of  the  General  History. 

Eyes  present     Tubicolaria. 

One  eye  present  (when  young)  Stephanoceros. 

/Envelope  of  the  single  animal- 1  Limnias. 

^  ,  ^  ,  J         cules  distinct  or  separated...  J  Cephalosiphon. 

Eotary  organ   two-parted  !  ^  j       r  r- 

when  fuU-grown ,  ^      ,„p,  „f  y,,  ,;     ,   ,„i^,,. ,  ^.^^^^ 

\     cules  conglomerated   J 

Eotary  organ  four-parted  when  full  grown     Melicerta. 

i^  Rotary  organ  five-  to  six-parted  when  full-grown Floscularia. 


Two  eyes 
present 
(when      j 
young) 


Dujardin  has  a  family  of  "  Flosculariens,"  which,  however,  differs  much 
from  that  of  Ehrenberg,  both  in  its  distinctive  characters  and  in  the  species 
assigned  to  it.  The  French  naturalist  includes  only  two  genera,  viz.  Flos- 
cularia  and  Stephanoceros.  Contrary  to  Ehrenberg's  assertion,  these  two 
genera  are  stated  by  Dujardin  to  be  destitute  of  a  rotary  organ,  and  indeed 
of  vibratile  cilia,  and  are  described  as  ha\dng  a   campanulatc,  contractile 


OF  THE  FLOSCULARI^A.  667 

body,  tapering  towards  the  base  so  as  to  form  a  long  pedicle,  by  which  they 
affix  themselves  to  solid  bodies.  Their  mouths  are  furnished  with  horny  jaws. 
Speaking  of  their  affinities,  he  remarks,  ''  The  Flosculariens,  like  the  MeH- 
certiens,  also  have  a  certain  affinity  in  form  with  the  Yorticelliens  and  the 
Stentors,  and  also  with  the  Campanularue  among  polypes.  They  live  in  the 
same  way,  fixed  to  water-plants  by  the  pedicle  of  their  campanulate  body,  the 
margin  of  which  presents  five  or  six  lobes,  terminated  by  appendages  or  ciha, 
without,  however,  any  indication  of  a  vibratile  movement.  At  the  bottom  of 
this  wide  opening  is  situated  the  mouth,  provided  with  jaws  attached  to  a 
muscular  bulb,  less  frequent  and  regular  in  its  movements  than  the  other 
Rotatoria.  In  Floscularia  the  jaws  are  simple,  and  the  lobes  of  the  (anterior) 
margin  short,  but  with  long  radiating  cilia ;  whilst  in  StepTianoceros  the  jaws 
are  compound,  and  the  marginal  lobes  veiy  long  and  covered  with  short 
cUia."  Dujardin  states  fui^ther,  that  the  gelatinous  case  of  Floscularia  may 
disappear,  and  therefore  cannot  be  used  as  a  generic  distinction,  either  in  the 
case  of  that  genus  or  indeed  of  the  other  genera  included  in  Ehrenberg's 
family  of  the  same  name.  Entertaining  this  opinion  of  the  differences  of  the 
gelatinous  envelope  being  accidental,  not  constant,  Dujardin  rejects  the  genus 
Limnias  as  not  distinct  from  Lacinularia,  whilst  he  denies  that  the  latter  is 
generically  distinct  from  Megalotroclia — a  conclusion  in  which  Huxley  is  dis- 
posed to  agree  with  the  French  natm-alist.  Of  the  remaining  genera  of 
Ehrenberg's  family  Flosculariaea,  viz.  Tuhicolaria,  Lacinularia,  and  Melicerta, 
to  which  he  adds  Ptygura,  already  described,  Dujardin  constitutes  a  family 
which  he  terms  Melicertiens.  In  some  of  these  objections  there  is  force. 
Floscularia  and  Steplianoceros  undoubtedly  differ  from  the  remaining  genera 
in  the  form  assumed  by  ciliated  appendages  supposed  to  represent  the  trochal 
disk  of  Melicerta  and  Lacinularia.  Gosse  states  that  in  Floscularia  rotation 
is  accomplished,  not  by  the  tufts  of  long  setee,  but  by  cilia  set  on  the  inner 
surface  of  the  disk,  which  cause  the  currents  to  converge  to  the  mouth  of  the 
animal ;  hence,  if  the  setigerous  bulbs  of  Floscularia  and  the  ciliated  arms  of 
Steplianoceros  are  not  the  homologues  of  the  true  trochal  disks  of  Melicerta, 
the  propriety  of  Ehrenberg's  definitions  is  seriously  impaired.  But  we  see 
no  reason  for  rejecting  this  homology  in  the  case  of  Steplianoceros  merely 
because  the  motion  of  the  verticillate  cilia  is  periodic  and  interrupted  instead 
of  continuous :  and  if  Mr.  Gosse  is  correct  in  his  conception  respecting  Floscu- 
laria, it  is  equally  entitled  to  its  present  place ;  for  whilst,  on  the  one  hand, 
it  is  not  essential  to  a  trochal  disk  that  its  moving  ciha  should  be  arranged  at 
its  margin,  on  the  other,  these  cilia  do  not  exclude  the  possibility  of  other 
appendages,  such  as  the  pencils  of  setae  in  Floscularia,  being  attached  to  the 
same  organ,  though  such  appendages  may  have  no  homologues  amongst  the 
other  Eloscularian  genera. 

Dujardin's  objection  respecting  the  gelatinous  case  oi  Floscularia  is  probably 
based  on  error.  Mr.  Gosse  has  shown  that  in  some  cases  it  is  so  thin  that  it 
might  easily  be  overlooked,  without  great  care  being  taken  to  discover  it. 

Leydig  of  course  rejects  Ehrenberg's  family  of  Floscularia,  arranging  the 
animals  composing  it  in  his  first  group,  along  with  (Ecistes  and  Conocliilus, 
with  which  they  have  unquestionably  a  veiy  close  affinity. 

The  creatures  composing  this  family  are  undoubtedly  among  the  most 
interesting  and  beautiful  of  Infusorial  animals.  Their  developed  organiza- 
tion, and  singular  habits,  render  them  objects  of  the  highest  interest,  both 
to  the  naturalist  and  the  physiologist;  whilst  their  exquisitely  beautiful 
contour  and  the  magnificent  phenomena  presented  by  the  trochal  cilia  when 
in  active  rotation,  never  fail  to  impress  even  the  most  careless  of  observers 
with  a  sense  of  wonder  and  delight. 


608 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Genus  TUBICOLARIA  (XXXII.  379-382).  —  Figm-e  clavate,  with  a 
transparent  gelatinous  case.  Eotary  organ  deeply  fissured  on  the  abdominal 
aspect,  and  less  strongly  on  the  dorsal  side,  by  which  it  is  divided  into  two 
lappets,  each  of  which  is  again  partially  subdivided  into  two.  Ciliary  wreath 
double,  with  a  space  between  the  rows.  Mouth  opening  directly  into  the 
oesophageal  bulb,  in  front  of  w^hich  is  a  small  vesicular  organ  filled  with  pale- 
reddish  matter.  Stomach  long,  with  thick  cellular  walls  and  four  glandular 
organs  surrounding  its  uj^per  extremity.  Intestine  thin  and  clear,  cui^ving 
slightly  forward  towards  the  anus.  Two  water-vascular  canals  extend  along 
the  body,  apparently  forming  a  network  at  the  head,  and  bearing  a  couple  of 
vibratile  tags.  No  contractile  vesicle  observed  at  their  cloacal  extremity. 
Foot,  by  means  of  which  it  adheres  to  foreign  bodies,  terminated  by  a  bundle 
of  cilia.  Two  tentacles  extend  from  the  abdominal  surface,  a  little  below 
the  mouth ;  each  has  a  clear  fibrous-looking  tract  along  its  centre,  and  is 
terminated  by  a  bundle  of  setae.  Embryo  with  the  gelatinous  sheath  colour- 
less, but  acquiring  consistency  and  a  yellowish  hue  with  advancing  age.  There 
is  a  small  concretionary  mass,  apparently  surrounded  by  a  sac,  affirmed  by 
some  to  be  urinary,  in  the  body  of  the  embryo. 


TuBicOLARiA  Najas. — The  jaws  have 
four  teeth ;  and  the  tactile  tubes  are  hairy 
anteriorly.  This  animal  is  described  fidly 
in  the  account  of  the  genus ;  and  xxxn. 
378-382  will  illustrate  it.  381  represents 
the  animals  of  natm-al  size,  as  found  at- 
tached to  the  roots  of  Lemna  polyirhiza, 


with  those  of  the  following  genus ;  fig. 
379  represents  an  animalcule  within  its 
case,  the  rotary  organ  withdrawn;  fig. 
380,  another  extended,  and  without  its 
lorica ;  fig.  382,  the  oesophagus,  with  the 
jaws  and  teeth  separate.     1-36". 


Genus  STEPHANOCEROS  (XXXII.  383;  XXXVII.  1-4).  — Figure 
clavate,  with  five  long  arms  at  its  anterior  extremity,  siuTounded  by  verticils 
of  cilia.  Sheath  without  parallel  sides  and  with  strong  parallel  folds  or 
curves ;  either  crystalline  without  any  foreign  admixture,  or  sometimes  over- 
spread with  small  linear  bodies  like  small  dead  Vibrios  or  Microglence.  It 
apparently  is  not  tubular,  but  a  solid  gelatinous  mass  envelopes  the  animal 
as  liigh  up  as  the  base  of  the  rotary  arms.  Acetic  acid  renders  it  white,  and 
nitric  acid  renders  its  outline  more  clear.  Beneath  the  cuticle  is  a  granular 
layer  containing  nucleated  cells.  The  cilia  of  the  arms  appear  planted  in  a 
granular  stratum  external  to  the  cuticle,  from  which  they  are  detached  in 
bundles  when  subjected  to  slight  pressure.  A  deep  transverse  fold  of  the 
integument  exists  at  the  base  of  the  rotary  organ,  and  contraction  throws  the 
peduncle  into  corresponding  folds.  Between  the  skin  and  the  viscera  are 
numerous  branching  corpuscles  resembling  cells  of  connective  tissue.  These 
cells  correspond  with  what  were  described  by  Professor  Williamson  in  Meli- 
certa  rtngens.  They  look  like  smaU  globules  of  ductile  protoplasm,  and  closely 
resemble  the  ductile  bands  seen  in  Noctiluca  miliar  is.  It  is  not  impossible 
that  these  may  really  be  some  unchanged  remains  of  the  protoplasm  of  the 
ovum,  which  they  closely  resemble.  Four  long  muscles,  contained  in  sarco- 
lemmata  or  sheaths,  proceed  from  the  foot  anteriorly,  branching  dichotomously. 
Alimentary  canal  composed  of  a  funnel-like  oral  ca\ity,  opening  into  a  still 
wider  proventriculus  ha\'ing  an  intermediate  septum  and  four  long  bristles 
with  hooked  extremities,  then  a  globular  maxillary  bulb,  conducting  to  a 
special  stomach,  which  terminates  in  a  short  intestine.  The  oral  cavity  is 
lined  with  fine  cilia ;  and  the  proventriculus  consists  of  two  membranes,  not 
in  close  contact,  but  with  a  narrow  intermediate  space.  The  maxillary  teeth, 
the  lining  of  the  maxillary  bulbs,  and  the  cesoi^hageal  bristles  resist  the 
action  of  li(]uor  potassac,  indicating  a  chitinous  composition.     The  walls  of  the 


OF  THE  FLOSCULARI/EA.  (509 

stomach  have  a  thick  layer  of  large  cells  filled  with  j'ellow  granules  or  fat- 
corpuscles.  Intestine  transparent  and  ciliated  internally.  A  contractile  sac 
connected  with  the  cloaca,  from  which  spring  two  broad  water-vascular 
canals,  which  are  lost  anteriorly  in  front  of  a  fatty  mass  surrounding  the 
proventriculus.  Ovarium  developing  but  few  ova  at  a  time ;  these,  w^hen 
discharged  from  the  ovary,  are  still  seen  to  be  enclosed  in  a  membranous 
o^-iduct,  extending  from  the  ovary  to  the  cloaca.  No  male  organ  hitherto 
discovered. 

Immediately  above  the  proventriculus  is  a  large  collection  of  hyaline 
vesicles,  which  e\ddently  open  externally  by  a  short  duct.  A  dark  granular 
vesicle  appears  at  the  posterior  end  of  the  body  of  the  embryo,  as  in  Tubico- 
laria  and  Melicerta, — supposed  by  some  authors,  but  without  sufficient  reason, 
to  be  a  uiinary  concretion.  Two  eye-specks  at  the  opposite  extremity  of  the 
embryo.  Two  vibratile  spaces  also  a23pear  simultaneously,  the  one  in  front 
of  the  other.  The  vibratile  action  is  active  within  the  anterior  one,  whilst 
witliin  the  other  a  few  long  cilia  undulate  slowly. 

"WTien  the  embryo  is  iii'st  distinguishable,  and  separable  from  the  egg,  it 
has  a  vermiform  figure,  and  is  about  124  millimetres  in  length.  The  head, 
supporting  the  eyes,  is  separated  from  the  body  by  a  constriction ;  its  margin 
is  furnished  with  numerous  cilia,  the  whole  being  retractile.  Within  the 
body  and  behind  the  head  are  several  longitudinal  stripes  of  a  doubtful 
natiu'e ;  and  still  more  posteriorly  is  a  clear  space  with  some  long  ciHa  in 
action,  which  may  represent  the  alimentary  cavity ;  the  maxillary  jaws  are 
perceptible,  and  the  posterior  extremity  furnished  with  some  cilia.  On  one 
occasion  Leydig  met  ^\ith  another  form  of  embryo,  which  retained  the  vermi- 
form aspect  in  its  body  and  foot,  but  with  the  former  elongated,  and  termi- 
nated by  four  arms.  Two  eye-specks  present,  and  a  proboscis  in  front,  with 
two  extended  tubular  processes  terminated  by  cilia.  Extremity  of  the  foot 
devoid  of  cilia.  The  maxillae  were  fully  developed ;  and,  near  the  sac  with 
the  dark  granular  concretions,  ciliary  vibration  was  discernible.  Leydig 
thinks  that  the  dark  granules  of  the  sac  escape  into  the  cloaca,  and  regards 
them  as  ui'inary  concretions  accumulated  in  the  extremity  of  the  intestine. 
Cohn  rejects  the  idea  that  they  so  escape ;  and  we  believe  him  to  be  correct 
on  this  point.     The  granules  are  affected  by  potash,  but  not  by  acetic  acid. 

Stephanoceros    Eichhornii  (xxxii.  I  xxxn.  383,  the  eye  and  tags  are  visible,  and 


383;  xxxvii.  1-4).  —  The  case  transpa- 
rent, like  glass;  rotary  organ  with  five 
lobes  or  arms,  each  furnished  with  fifteen 
verticils  of  cilia ;  these  arms  act  occasion- 
all}^  as  prehensile  instruments.  As  the 
eggs  are  detained  in  the  case  until  the 
young  are  hatched,  Ehrenberg  erroneously 
considers  this  creature  viviparous.     In 


over  the  latter  what  Ehrenberg  caUs  gan- 
glia. The  case  is  discerned  with  difficulty, 
from  its  very  transparent  natm-e,  unless 
indigo  is  mixed  with  the  water.  1-36". 
S.  glacialis. — Only  one  specimen  seen 
without  its  stem.  '  The  five  arms  not 
furnished  with  ciliary  whorls,  but  with 
sino^le  bristles.     1-14'". 


The  internal  organization  oi  Stephanoceros  is  well  illustrated  in  XXXVII.  1 : 
h  is  the  pharyngeal  bulb,  resting  upon  a  proventriculus  or  crop  c,  below 
which  is  the  maxillary  bulb  d,  containing  the  jaws ;  e  is  the  stomach,  with 
its  large  cells  ;  whilst  /  is  the  intestine,  terminating  at  the  cloaca ;  g  is  the 
ovary  containing  ova ;  h  indicates  delicate  longitudinal  muscles,  extending 
down  the  peduncle;  and  tt  the  water-vascular  canals  with  their  vibratile 
tags. 

In  fig.  2  the  detached  ovary  is  represented,  consisting,  as  is  usual  amongst 
the  Rotatoria,  of  a  delicate  membranous  sac,  /,  prolonged  into  an  o\dduct. 
The  contained  ova  are  seen  in  different  stages  of  development.  At  a  is  the 
stroma  or  granular  mass,  with  its  germs ;  h  is  an  ovum  in  the  first  stage  of 


670  SYSTEMATIC  HISTOET  OF  THE  INFUSORIA. 

fission ;  at  c  the  ovum  has  undergone  several  repetitions  of  the  yelk- division ; 
and  at  d  is  an  ovum  in  which  the  contour  of  the  embryo  is  visible.  The  two 
eye-spots  seen  at  d ;  and  the  so-called  dark  urinary  concretion,  seen  also  in 
embryonic  Melicertce  and  others,  at  Jc.  The  real  nature  of  this  last  object, 
which  is  seen  only  in  the  embryonic  state  of  these  animals,  is  yet  doubtful. 
Fig.  3  represents  a  very  young  Ste^hanoceros  a  little  after  its  liberation 
from  the  ovum ;  and  fig.  4  another  immediately  after  its  liberation  from  its 
shell.  The  dorsal  aspect  of  the  jaws  of  the  maxillary  bulb,  according  to 
Mr.  Gosse,  is  represented  in  XL.  27,  and  the  obhque  aspect  of  the  incus  in 
XL.  28. 

Genus  LIMMAS  (XXXII.  388-392;  XXXYI.  2).  —  Eyes  two;  case 
(ui'ceolus)  solitary ;  rotary  organ  two-lobed  when  fully  grown,  being  then 
constricted  in  the  middle  ;  alimentaiy  canal  simple,  terminating  at  the  base 
of  the  foot  or  tail ;  stomach,  two  jaws  mth  teeth,  and  two  glands  also 
present.  The  ova  are  deposited  within  the  case,  where  they  are  developed ; 
neither  male  organs  nor  water- vascular  canals  discovered ;  two  visual  organs 
indicate  sensation:  these  in  the  young  animalcules  are  red,  and  are  even 
visible  within  the  ovum ;  but  in  old  age  the  colour  disappears,  and  hence 
they  are  not  seen.  In  the  middle  of  the  rotary  organ,  when  expanded,  are 
seen  foiu'  large  globules,  which  Ehrenberg  erroneously  considers  nervous 
ganglia,  or  brain. 


LiMNiAS  Ceratophylli  (xxxii.  388-392 ; 
XXXVI.  2). — Case  white  at  first,  after- 
wards brown  or  blackish;  smooth,  but, 
being  viscid,  often  covered  with  extra- 
neous particles ;  its  connexion  with  the 
animalcule  is  a  voluntary  act  of  _  the 
latter;  the  two  red  eyes  and  the  jaws 
may  be  observed  in  the  ova  when  de- 
veloped; by  giving  the  latter  a  gentle 
pressm-e  the  sheU  bursts,  xxxn.  389 
exhibits  an  animalcule  just  emerged  from 
the  e^^,  392  ;  391  a  young  specimen, 
with  a  rotary  organ  nearly  circular,  and 
two  eyes ;  390  a  full-grown  specimen, 
without   its    case,  fed   on   indigo — the 


jaws  (each  of  which  has  three  strong 
teeth),  the  ova,  and  the  traces  of  lon- 
gitudinal muscles  are  seen,  the  wheel 
is  folded  up ;  388  another,  within  its 
case,  having  the  lobed  rotary  organ  ex- 
panded, (xxx^i.  2.  is  more  magnified.) 
Found  upon  hornwort  (Ceraiophyllum) 
and  other  aquatic  plants.  Length  about 
1-20";  case  1-40". 

L.  annulatus  (Bailey). — The  case  is 
ribbed  and  semitransparent,  and  is  com- 
posed of  a  linear  series  of  rings.  Found 
in  a  ditch  at  Witlingham,  near  Norwich, 
on  duck  weed  (Brightwell)  ;  and  by  Dr. 
Bailey  near  New  York,  U.S. 


Genus  CEPHALOSIPHON.  —  Eotary  organ  bilobed ;  eyes  two  ;  sheath 
single  ;  two  frontal  horns,  including  the  siphon. 

Cephalosiphon  Limnias. — Sheath  membranous,  annulate.  1-6"'  to  1-5"'.  On 
Ceratophyllum.     Berlin,  Jul3^ 

Genus  LACINULARIA  (XXXVII.  19-25).  — Eyes  two  (in  the  young 
state) ;  the  cases  (urceoli)  conglomerate,  or  growm  together ;  rotary  organ 
two-lobed  when  fuU-grown,  but  nearly  circular  when  young :  this  organ  is 
the  chief  instrument  of  locomotion.  Band-like  longitudinal  muscles  exist 
within  the  body.  Pharyngeal  bulb  large,  with  two  jaws,  and  teeth  in  rows ; 
oesophagus  short,  narrow ;  stomach  elongated,  transversely  constricted,  and 
with  cEecal  (?)  appendages ;  short.  The  ovarium  is  situate  about  the  middle 
of  the  body,  and  opens,  along  with  the  intestine  and  the  contractile  sac  of 
the  water- vascular  canals,  into  the  caecum.  Visual  organs  exist  in  the  young 
state ;  red  in  the  developed  ovum,  but  becoming  darker  as  they  advance  to 
maturity.  Globular  bodies  support  the  oesophagus  on  each  side ;  and  below 
the  mouth  is  a  small  organ,  supposed  to  be  the  brain. 


OF  THE  FLOSCULARl^A. 


671 


Lacinularia  sociaUs  {Vmiicella  so- 
ckilis  et  Jlosculosa,  M.)  (xxxvii.  19).— 
Envelope  gelatinous,  transparent,  in 
which  are  implanted  numerous  indivi- 
dual animals,  that  have  imitedly  thrown 
out  the  gelatinous  secretion  in  which 
they  are  imbedded.  Body  elongated,  co- 
nical pedimcle  (xxxvii.  19  k)  trimcated 
and  foniiing  at  its  posterior  extremity 
a  sucker,  attaching  the  animal  to  the 
foreign  object  supporting  the  entire 
group.  Trochal  disc  at  the  anterior  ex- 
tremity of  the  body,  into  which  it  is 
drawn  when  at  rest  (xxxvii.  19  a),  but 
expanding  into  a  horseshoe-shape,  vnXh. 
a  double  row  of  cilia  round  its  margin. 
Mouth  in  the  notch  of  the  ti'ochal  disk. 
Pharynx  leading  to  a  phar^-ngeal  bulb 
(19  b),  in  which  the  jaws  are  planted. 
These  are  not  stirrup-shaped,  as  described 
by  Ehrenberg,  but  composed  of  four 
pieces  (xxxvii.  20).  (Esophagus  passing 
through  the  bulb  reaches  the  first  sto- 
mach (19  c),  into  which  two  cellular 
appendages,  regarded  by  Ehrenberg  as 
pancreatic,  open.  Below  this  is  a  second 
dilation  (19  c?),  furnished  with  several 
short  cellular  caeca,  and  still  lower  a 
third,  more  globular  segment  (19  e), 
also  fui-nished  with  external  cellular 
caeca,  and  clothed  internally  with  long 
cilia.  From  this  a  short  intestine,  ac- 
cording to  Huxley,  turns  upwards  and 
outwards,  terminating  in  a  cleft  of  the 
integimient  on  the  same  side  as  the 
mouth.  This  "  intestine "  is  probably 
the  cloaca  of  other  writers.  Two  water- 
vascular  canals  (19 1)  arise,  one  on  each 
side  of  the  intestine  (cloaca),  and  ascend 
on  opposite  sides  of  the  body  towards 
the  head.  They  divide  opposite  the  pha- 
ryngeal bulb,  each  into  three  branches, 
one  of  these  uniting  with  its  fellow,  the 
others  teraiinating  as  caeca ;  within  these 
are  distributed  five  pairs  of  long  vibratile 
cilia.  Vacuolar  thickenings  of  the  in- 
tegument exist  in  several  parts  of  the 
body.  A  small  ciliated  sac  is  located 
below  the  mouth,  and  still  lower  is  a 
small  organ  believed  by  Prof,  Huxley  to 
be  the  cerebral  ganglion.  Two  eye-spots 
occur  on  the  trochal  disc  of  the  young 
animal  (xxxvn.  11),  but  they  disappea^r 
in  the  adult.  No  male  reproductive 
organ  hitherto  discovered.  Prof.  Hux- 
ley's description  of  the  female  organs, 
and  the  development  of  the  ova,  is  as 
follows : — "  The  ovarj-  consists  of  a  pale, 
slightly  granular  mass,  of  a  ti-ansversely 
elongated  form  (19  A),  and  somewhat 
bent  round  the  intestine ;  it  is  enclosed 
in    a   delicate    transparent    membrane, 


which  is  hardly  \4sible  in  the  unaltered 
state,  but  becomes  very  ob^dous  by  the 
action  of  acetic  acid,  which  contracts 
the  substance  of  the  ovary  and  throws 
the  membrane  into  sharp  folds." 

Pale  clear  spaces  (xxx^t:i.  7),  which 
sometimes  seem  to  be  limited  by  a  distinct 
membrane,  are  scattered  through  the 
substance  of  the  ovaiy;  and  in  each  of 
these  a  pale  circular  nucleus  is  contained. 
The  nucleus  is  more  or  less  opaque,  but 
usually  contains  from  one  to  three  clear 
spots.  These  are  the  germinal  vesicles 
and  spots  of  the  future  ova.  Acetic  acid, 
in  contracting  the  pale  substance,  groups 
it  round  these  vesicles,  wdthout,  how- 
ever, breaking  it  up  into  separate  masses. 
It  renders  the  nuclei  more  evident. 

The  ova  are  developed  thus : — One  of 
the  vesicles  increases  in  size ;  and  reddish 
elementary  granules  appear  in  the  ho- 
mogeneous substance  aroimd  it.  This 
accumulation  increases  imtil  the  ovum 
stands  out  from  the  surface  of  the  ovary, 
but  invested  by  its  membrane,  which,  as 
the  o\'um  becomes  separated,  takes  the 
place  of  a  vitelline  membrane. 

In  the  meanwhile  the  geraiinal  ve- 
sicle has  increased  in  size ;  and  its  nu- 
cleus is  no  longer  visible.  In  the  o^imi 
it  appears  as  a  clear  space ;  isolated  by 
crushing  the  ovum,  it  is  a  transparent, 
colourless  vesicle.  The  perfect  ova  are 
oval,  about  1-10"  in  diameter,  and  are 
extruded  by  the  parent  into  the  gela- 
tinous connecting  substance,  where  they 
undergo  their  development. 

The  changes  that  take  place  after  ex- 
trusion, or  even  to  some  extent  within 
the  parent,  are — 1,  the  disappearance  of 
the  germinal  vesicle  (as  Huxley  judged 
from  one  or  two  ova  in  which  he  could  find 
none) ;  2,  the  total  division  of  the  yelk  (as 
described  by  Kolliker  in  Megalotrochci), 
imtil  the  embryo  is  a  mere  mass  of  cells 
(xxx\Ta.  5,  6,  8,  9),  from  which  the  va- 
rious organs  of  the  fcetus  are  developed. 

The  yoimgest  foetuses  are  about  1-70" 
in  length.  The  head  abruptly  trun- 
cated (xxxvii.  10),  and  separated  by  a 
constriction  from  the  body.  A  sudden 
naiTowing  separates  the  other  extremity 
of  the  body  from  the  pedimcle,  which  is 
exceedingly  short,  and  provided  with  a 
ciliated  cavity  (a  sort  of  sucker)  at  its 
extremity.  The  head  is  nearly  circidar, 
seen  from  above,  and  presents  a  central 
protuberance,  in  -which  the  eye-spots  are 
situated.  The  margins  of  this  protu- 
berance are  provided  with  long  cilia, 
which  will  become  the  upper  circlet  of 
cilia  in  the  adult.    In  young  Laehndarice 


672 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


1-30"  in  length,  the  head  has  become 
triangular  (xxxvii.  11),  and  thus  it  gra- 
dually takes  on  the  perfect  form.  The 
yoimg  had  previously  crept  about  in  the 
gelatinous  investment  of  tlie  parents ; 
they  now  begin  to  "  swarm,"  uniting 
together  by  their  caudal  extremities,  and 
are  readily  pressed  out  as  free-swimming 
colonies,  resembling  in  this  state  the 
genus  Conochilus  (Huxley).  But,  besides 
the  ova  whose  development  is  thus  de- 
scribed. Professor  Huxley  observed  a 
second  class,  to  which  he  refers  as  fol- 
lows: — "In  a  fully-grown  Lacmularia 
which  has  produced  ova,  the  ovary,  or  a 
large  portion  of  it,  begins  to  assume  a 
blackish  tint  (xxxvii.  22);  the  cells, 
with  their  nuclei,  undergo  no  change, 
but  a  deposit  of  strongly  refracting  ele- 
mentary granules  takes  place  in  the  pale 
connecting  substance.  Every  transition 
may  be  traced,  from  the  deep  black  por- 
tions to  unaltered  spots  of  the  ovarium ; 
and  pressure  alwa3'S  renders  the  cells 
with  their  nuclei  visible  amongst  the 
granules.  The  investing  membrane  of  the 
ovary  becomes  separated  from  the  dark 
mass,  so  as  to  leave  a  space ;  and  the  outer 
surface  of  the  mass  invests  itself  vA\\\ 
a  thick  reddish  membrane  (xxxvii.  24), 


which  is  rough,  elastic,  and  reticulated 
from  the  presence  of  many  minute  aper- 
tures. This  membrane  is  soluble  in  both 
hot  nitric  acid  and  caustic  potass.  The 
nuclei  and  cells,  or  rather  the  clear  spaces 
indicating  them,  are  still  visible  upon 
pressm-e,  and  may  be  readily  seen  by 
bursting  the  outer  coat.  By  degrees  the 
ephippial  ovum  becomes  lighter,  until  at 
last  its  colour  is  reddish-brown,  like  that 
of  ordinary  ova ;  but  its  contents  are  now 
seen  to  be  divided  into  two  masses,  hemi- 
spherical from  mutual  contact  (f.  21).  If 
this  body  be  now  crushed,  it  will  be  f  oimd 
that  an  inner  structureless  membrane 
exists  within  the  first-stated  membrane, 
and  sends  a  partition  inwards  at  the  line 
of  demarcation  of  the  two  masses.  The 
contents  are  precisely  the  same  as  before, 
viz.  nuclei  and  elementary  granules.  I 
was  unable  to  trace  the  development  of 
these  ephippial  ova  any  fm-ther." 

Professor  Huxley  thus  indicates  his 
belief  in  the  existence  of  two  classes  of 


thinks  probably  requires  sexual  fecunda- 
tion, whilst  the  others  do  not.  Cohn 
believes  that  the  bodies  usually  termed 
ova  by  Huxley  and  others  are  not  so, 
but  internal  gemmae. 


Genus  MELICERTA  (XXXII.  386, 387 ;  XXXVI.  1 ;  XXXVII.  12-18)- 
— With  a  case  or  envelope ;  solitary ;  rotary  organ  simple,  with  four  lobes 
when  expanded ;  free  longitudinal  muscles  for  the  contractions  of  the  body ; 
alimentary  canal  divided  into  segments,  in  one  of  which  (the  pharyngeal 
bulb)  are  complex  jaws ;  mouth  situate  at  the  bottom  of  the  cleft  between 
the  two  larger  lobes  of  the  rotary  organ ;  the  orifice  of  the  cloaca  near  the 
junction  of  the  long  peduncle  mtli  the  body.  Male  generative  organization 
unknown;  believed  by  Mr.  Gosse  to  be  dioecious.  Female  organs  a  large 
ovary  filled  with  granular  protoplasm  and  germinal  vesicles,  as  in  the  pre- 
ceding genus,  but  with  a  distinct  oviduct  opening  into  the  cloaca.  Two 
water-vascular  canals,  arising  from  a  contractile  vesicle,  ascend  towards  the 
head.  Two  tactile  appendages,  with  setigerous  extremities,  on  each  side  the 
head.     Two  eye-spots  in  the  young  animal.     Nervous  system  uncertain. 


Melicerta  ringens.  —  Case  (xxxvi. 
1  d)  conical,  granulated,  resembling  a 
honey-comb,  of  a  brownish-red  colour; 
it  is  composed  of  small  lenticular  bodies, 
secreted  and  deposited  by  the  animalcule ; 
these  are  agglutinated  by  a  peculiar 
viscid  matter,  afterwards  hardened  in 
the  water.  Into  this  tulie  the  soft  cry- 
stalline or  whitish  animalcule  can  with- 
draw itself;  and  when  its  flower-like 
wheel-work  (la)  is  expanded,  the  vibra- 
tile  cilia  appear  to  run  along  the  margin  of 
this  organ ;  but,  in  fact,  each  single  cilium 
only  turns  itself  upon  its  base,  their  aggre- 
gate motion  causing  a  little  whirlpool  in 


the  water,  directed  towards  the  mouth, 
which  is  situated  in  the  middle  of  the  two 
large  leaflets  of  the  rotary  organ;  the  eyes 
in  the  young  animal  are  placed  near  the 
two  other  bent  leaflets,  which,  according 
to  Ehrenberg,  are  analogous  to  a  cleft 
upper  lip  of  the  dorsal  surface :  the  dis- 
charging orifice  is  on  the  same  side;  and 
therefore  the  dorsal  tail-like  portion  be- 
comes a  ventral  member  or  foot,  (xxxii. 
386,  an  animalcule  within  its  case,  having 
the  rotary  organ  contracted ;  fig.  387,  with 
the  trochal  disc  fidly  expanded  :  the  case 
is  given  in  outline  only,  in  order  to 
show  the  internal  structure. )  On  Lemnae 


OF  THE  FLOSCULAEIJKA. 


673 


and  other  aquatic  plants.  Length  1-12"  5 
case  1-24"  ;  egg  1-150". 

The  pellets  forming  the  case  were 
thought  by  Ehrenberg  and  others  to  be 
deposited  from  the  cloacal  orifice ;  but, 
from  the  careful  researches  of  Mr.  Gosse, 
this  appears  to  be  an  error  (Trans. 
Microsc.  Soc.  1851,  vol.  iii.  part.  ii.  p.  Q2). 
That  observer  points  out  the  existence 
of  a  special  rotating  organ  of  a  cup-like 
figui-e  (xxxvi.  1  c)  (the  disc  seen  above), 
seated  immediately  above  the  projecting 
tube.  This  organ  "^he  saw  fill  and  empty 
itself  "  many  times  in  succession,  until 
a  goodly  array  of  dark  pellets  were  laid  " 
down  irregularly,  the  animal  efifecting 
their  distribution  by  bending  its  head 
downward,  so  as  to  bring  this  cup  and 
the  margin  of  its  sheath  into  apposition. 
"  After  a  certain  mmiber  were  deposited 
in  one  part,  the  animal  would  suddenly 
tm-n  itself  round  in  its  case  and  deposit 
some  in  another  part.  It  took  from  two 
and  a  half  to  three  and  a  half  minutes  to 
make  and  deposit  a  peUet."  Coloured 
particles  in  the  water  "  are  hurled  round 
the  margin  of  the  ciliated  disc,  until  they 
pass  ofi"  in  front  through  the  great  sinus 
between  the  large  petals ; "  and  the  atoms, 
if  few,  "glide  along  the  facial  sui'face, 
following  the  irregularities  of  the  out- 
line with  great  precision,  dash  roimd  the 
projecting  chin,  and  lodge  themselves 
one  after  another  in  the  little  cup-like 
receptacle  beneath,"  in  which  again  they 
are  whirled  round  with  great  rapidity, 
and  prepared  into  pellets  for  the  building 
up  of  the  case  of  the  animal. 

The  internal  organization  of  this  ani- 
mal has  been  investigated  by  Professor 
Williamson.  Like  Lacimdaria,  the  tro- 
chal  disc  is  double  at  its  margin,  with 
two  rows  of  rotary  cilia,  the  currents 
created  by  which  are  directed  to  the 
mouth  and  pass  oft* by  the  ciliated  "chin" 
— a  small  additional  lobe  above  the  cili- 
ated cup  of  Mr.  Gosse.  On  each  side  of 
the  trochal  head  are  two  hollow  pro- 
cesses or  "  calcars  "  —  the  respiratory 
tubes  of  Ehrenberg,  but  which  are  pro- 
ba,bly  tactile  (xxxvii.  17  d).  These  ter- 
minate externally  in  a  deltoid  body  (13), 
from  which  projects  a  pencil  of  straight 
setae.^  Along  the  interior  of  this  tube  is 
a  delicate  muscular  band,  by  which  the 
setigerous  extremity  can  be  drawn  back- 
wards into  the  tube  (14),  and  the  setae 
thus  be  removed  out  of  danger.  The 
alimentary  canal  much  resembles  that  of 
Lacimdaria.  There  is  a  narrow  oeso- 
phagus conducting  do"waiwards  to  the 
pharyngeal  bulb  (figs.  17  e  and  23),  in 


which  are  implanted  the  peculiar  jaws : 
these  are  complex  (f.  26),  consisting  of 
equilateral  sets  of  numerous  transverse 
bars,  those  of  each  set  connected  at  their 
peripheral  extremities  by  an  arcuate  lon- 
gitudinal one,  and  at  their  inner  extre- 
mities by  a  double  broad  longitudinal 
one  prolonged  upwards  into  a  long  nar- 
row handle  or  process  which  meets  its 
fellow  of  the  opposite  side  at  a  kind  of 
hinge-like  joint.  These  jaws  work  upon 
one  another  with  a  crushing  motion  by 
means  of  the  above  joint, — the  upper  part 
of  the  alimentary  canal,  and  consequently 
the  food  swallowed,  passing  between 
them.  Below  the  pharyngeal  bulb  is  an 
oblong  stomach,  with  cellular  parietes 
and  lined  with  cilia.  A  constriction 
separates  this  from  a  lower  and  more 
spherical  portion  (17  g),  also  cellular 
and  lined  with  still  longer  cilia.  This 
opens  into  a  long  cloaca  (17  U),  which 
turns  suddenly  upwards  to  its  terminal 
outlet  (17  i).  The  interior  of  the  body 
contains  numerous  free  muscular  bands. 
These  are  especially  distinct  in  the  pe- 
duncle, along  the  entire  length  of  which 
several  of  them  run,  which  shorten 
the  body  in  its  axial  line.  Each  fasci- 
culus consists  of  transversely  striped  or 
voluntary  muscular  fibre,  and  is  enclosed 
in  a  sarcolemna  or  membranous  sheath 
(18).  Difiiised  through  the  body  of  the 
animal,  but  specially  distinct  at  the  up- 
per part  of  the  peduncle,  are  numerous 
small  masses  of  \dscid  gTanular  proto- 
plasmic substance,  Avhich  send  slender 
prolongations  to  each  other  and  to  the 
surrounding  parts,  reminding  the  ob- 
server of  the  pseudopodia  of  the  Rhi- 
zopods  and  the  internal  threads  of 
Noctiluca. 

The  water-vascular  system  consists  of 
two  canals  arising  from  a  small  pyrifomi 
contractile  vesicle  below  the  stomach, 
and  apparently  with  the  cloaca.  One 
ascends  on  each  side  of  the  alimentary 
canal  towards  the  head,  where  they 
branch.  Vibratile  tags  are  connected 
with  them. 

Professor  Williamson  describes  the 
ovary  as  "  a  hollow  sac  (xxx-^t:i.  23  y), 
consisting  of  a  very  thin  peUucid  mem- 
brane. It  is  filled  with  a  viscid  granular 
protoplasm  of  a  light  grey  colour,  in 
which  ai-e  distributed  from  twenty  to 
thirtv  nuclei,  each  having  a  diameter  of 
from' 1-1200"  to  1-1600".  Each  nucleus 
contains  a  large  nucleolus,  varying  in 
diameter  from  1-1600"  to  1-3500".  In 
its  normal  state  the  gi'anular  protoplasm 
is  of  a  unifoi*m  grev  colour,  flowing 
2x 


674 


SYSTEMATIC  niSTORY  OF  THE  rNFFSORIA. 


freely  out  of  the  ovary  when  the  latter 
i3  ruptured.  The  nuclei  situated  nearest 
the  centre  of  the  ovary  appear  to  be 
successively  selected  for  development. 
One  of  these  nearest  the  surface  attracts 
around  itself  a  small  portion  of  the  gra- 
nular protoplasm^  detaching  it  from  the 
remaining  contents  of  the  organ,  though 
in  close  contact  with  them.  The  portion 
thus  specially  isolated  gTadually  enlarges, 
assuming  at  the  same  time  a  darker  hue, 
whilst,  fi'om  its  central  position,  it  par- 
tially divides  the  upper  from  the  lower 
half  of  the  remaining  ovarian  protoplasm. 
At  the  same  time  the  central  nucleus 
sometimes  undergoes  some  slight  en- 
largement, and  its  nucleolus  appears  to 
become  absorbed.  The  position  of  this 
nucleus  in  the  centre  of  the  ovum  is 
now  indicated  by  an  ill-defined  trans- 
parent spot ;  but  on  bursting  the  proto- 
plasmic mass,  it  is  seen  to  be  a  small 
spherical  cell  about  1-1000"  in  diameter, 
having  ver}^  thin  pellucid  walls  and 
scarcely  any  visible  cell-contents.  When 
the  ovum  thus  segmented  from  the  ova- 
rian protoplasm  has  attained  its  full  size 
(xxxvii.  17  o),  it  becomes  invested  by  a 
thin  shell,  which  is  apparently  a  secre- 
tion from  its  own  surface." 

"  The  ovum  being  now  ready  for  ex- 
pulsion, it  is  slowly  forced  down  to  the 
lower  part  of  the  ovary,  the  stomachs 
being  drawn  upwards  and  to  one  side  in 
order  to  make  way  for  it.  Yielding  to 
the  pressure  produced  by  the  successive 
contractions  of  the  body,  the  ovum 
sweeps  round  the  inferior  border  of  the 
lower  stomach,  and,  passing  through  the 
dilated  oviduct,  enters  the  cloaca.  The 
latter  canals  become  entirely  everted,  as 
is  the  case  when  the  excrements  are  dis- 
charged ;  and  by  a  sudden  contraction 
the  ovum  is  expelled." 

Professor  Williamson  minutely  de- 
scribes the  conversion  of  the  yelk  into 
an  embryo — the  successive  segmenta- 
tions of  the  nucleus  and  surrounding 
yelk,  imtil  the  whole  becomes  a  cellular 
mass,  as  in  Lacimdaria.  The  first  visible 
evidence  of  life  is  the  production  of  a 
few  moving  cilia,  especially  near  the 
future  head,  followed  first  by  ti'aces  of 
the  dental  apparatus,  then  by  the  de- 
velopment of  the  various  organs,  in- 
cluding the  two  eye-spots,  soon  after 
which  the  young  animal  escapes  from 
its  shell. 

"  Almost  immediately  after  its  escape 

Genus  FLOSCULARIA  (XXXII.  384,  385 ;  and  woodcuts).— These  crea- 
tures possess  when  young  two  eye-spots.     Several  lobes  surround  the  head, 


from  the  e^^,  the  young  Melicerta 
stretches  itself  out,  and,  everting  the 
anterior  part  of  its  body,  unfolds  several 
small  projecting  mamillte  (xxxvii.  16), 
covered  with  large  cilia,  by  means  of 
which  it  floats  freely  away.  The  ciliated 
mamiUse  at  this  stage  of  growth  are  not 
unlike  those  seen  in  Notommata  clavu- 
lata,  but  they  soon  enlarge  and  become 
developed  into  the  fiabelliform  wheel- 
organs  of  the  matured  animal."  In  this 
stage  all  the  organs  of  the  perfect  animal 
are  present,  showing  that  the  creature 
passes  through  no  larval  form,  and  that  it 
is  not  identical  with  the  Ptygiira,  as  Ehr- 
enberg  and  others  have  thought.  After 
swimming  about  some  time,  a  dark- 
brown  spot  disappears  from  the  posterior 
part  of  the  body,  followed  by  the  eye- 
specks,  when,  the  same  writer  adds,  "  the 
animal  attaches  itself  by  the  tail  to  some 
fixed  support,  anddevelopes  from  the  skin 
of  the  posterior  portion  of  its  body  a  thin 
hyaline  cylinder,  the  dilated  extremity 
of  which  is  attached  to  the  supporting 
object.  This  structure  has  already  been 
noticed  b}'  Dr.  ManteU  (  TJioughts  on  Ani- 
malcules), though  I  have  never  seen  it 
so  largely  developed  as  is  represented  in 
his  figures.  The  yoimg  animal,  ha^dng 
chosen  a  permanent  resting-place,  com- 
mences the  formation  of  its  singular 
investing  case.  I  have  verified  Dr.  Man- 
tell's  account  of  the  position  occupied 
by  the  first-formed  spheres.  They  are 
arranged  in  a  ring  round  the  middle  of 
the  body  (xxx^t:i.  15),  and  are  for  some 
time  imattached  to  the  leaf  or  stem 
which  supports  the  animal.  They  appear 
to  have  some  internal  connexion  with 
the  thin  membranous  cylinder.  At  first 
new  additions  are  made  to  both  extre- 
mities of  the  enlarging  ring;  but  the 
jerking  constrictions  of  the  animal  at 
length  force  the  caudal  end  of  the  cylin- 
der down  upon  the  leaf,  to  which  it 
becomes  secui-ely  cemented  by  the  same 
viscous  secretion  as  causes  the  little 
spheres  to  cohere."  "When  the  ova  are 
discharged  fi'om  the  cloaca,  they  succes- 
sively fall  into  the  cavity  of  the  tessel- 
lated case,  where  they  undergo  develop- 
ment. I  have  often  foimd  as  many  as 
foui-  in  one  case  in  various  stages  of 
progress.  It  is  whilst  the  eggs  are  thus 
protected  that  the  young  animals  burst 
their  shells,  s^^^mming  out  at  the  fi'ee 
extremity  of  the  case  as  soon  as  they 
are  liberated." 


OF  THE  FLOSCULAEKEA. 


675 


each  surmounted  by  a  pencil  of  long  setae.  These  lobes  are  regarded  by 
Ehrenberg  as  the  rotary  organ ;  but,  according  to  Gosse,  the  upper  surface 
of  the  central  disc  fulfils  the  rotatory  functions.  Body  furnished  with  a 
long  peduncle,  by  which  the  animal  is  fixed,  and  the  whole  surrounded  by 
a  thin  diaphanous  case  resembling  that  seen  in  the  very  young  Melicerta. 
Erom  its  transparency  this  can  often  be  detected  only  by  colouring  the 
wat^r  with  some  pigment.  Alimentary  canal  simple,  conical.  Reproductive 
system  resembling  that  of  Lacinularia.  Ova  deposited  T\ithin  the  case. 
When  viewed  from  above,  the  head  of  the  animal  resembles  an  Acineta. 


Floscularia  prohoscidea. — Case  cy- 
lindrical, hyaline,  gelatinous.  Setigerous 
lobes  six,  with  short  cilia  sm'rounding  a 
ciliated  flexible  proboscis,  which  appears 
to  have  an  opening  at  its  extremity. 
Dujardin  thinks  this  proboscis  may  be 
nothing  more  than  one  of  the  ciliated 
lobes  advanced  towards  the  centre.  Body 
ovate,  ^^'ith  a  long  styliform  peduncle 
attached  to  the  base  of  the  case ;  when 
extended,  the  body  and  part  of  the  foot 
are  protruded.  Found  upon  the  leaves 
of  Hottonia  palustris.  Length  when  ex- 
tended 1-18";  case  1-36". 

F.  ornata  {Cercaria,  M.)  (xxxn.  384, 
385). — Case  or  envelope  hyaline;  very 
thin  at  its  upper  extremity ;  thicker,  and 
often  with  foreign  bodies  entangled  in 
it  inferiorly.  It  is  sometimes  very  slug- 
gish, but  at  others  moves  with  consider- 
able activity,  often  contracting  itself  very 
quickly  within  its  case.  The  setigerous 
lobes,  according  to  Gosse,  are  not  the 
true  rotatory  organs :  ''  yet,"  he  says, 
'^  there  is  a  rotatory  organ  —  the  par- 
ticles of  floating  matter  revohing  in  a 
pei-pendicidar  oval  within  the  mouth  of 
the  disc.  Hence  I  conclude  that  the 
rotatorv  cilia  are  set  on  the  inner  surface 
of  the  disc."  He  fm-ther  adds  :  "When 
the  pencil  of  united  tufts  is  in  process 
of  expansion  the  hairs  have  a  wavy, 
quivering  sort  of  motion,  but  when  ex- 
panded they  remain  perfectly  motionless. 
The  two  red  eyes  seen  in  the  young 
animal  ordinarily  disappear  in  the  adult ; 
but  Mr.  Gosse  has  occasionally  met  "«dth 
such  specimens  in  which  they  were  still 
plainly  visible.  He  has  observed  the 
body  "  to  be  lined  with  a  yellowish 
vascular  membrane,  which  does  not  ex- 
tend up  to  the  petals,  but  temiinates  at 
the  neck  with  a  free,  very  mobile  edge, 
forming  an  irregidar  opening,  the  out- 
line of  which  is  constantly  changing  by 


the  contraction  and  expansion  of  the 
membrane.  The  opacity  of  this  lining 
renders  it  diflicult  to  resolve  the  viscera." 
"Ehrenberg  speaks  of  an  oesophageal 
head  above  the  jaws ;  but  I  can  see 
nothing  of  the  kind,  and  am  inclined  to 
think  he  may  have  mistaken  the  ever- 
contractmg  opening  of  the  lining  mem- 
brane for  one."  These  animals  are  very 
fond  of  Chlamidomouas ;  and  when  swal- 
lowing large  bodies,  such  as  Naviculce, 
they  contract  the  entire  body.  Ehr- 
enberg has  numbered  as  many  as  five 
ova  retained  within  the  diaphanous  case 
at  the  same  time.  Gosse  once  counted 
nine.  These,  as  is  also  the  case  in  Meli- 
certa, are  generally  in  different  stages 
of  development,  —  in  some  the  per- 
fectly-formed embiyo  being  distinctly 
\dsible,  its  movements  and  its  two  reel 
eyes  being  very  manifest.  With  a  mo- 
derate pressm-e  Ehrenberg  burst  the  shell, 
which,  according  to  Gosse,  is  calcareous : 
the  young  animal  crawled  out  with  a 
slight  vibratory  motion ;  the  cilia  were 
short  and  not  very  distinct.  In  the 
mature  animal  the  pedimcle  is  truncate 
at  its  extremity.  Upon  Ceratophyllum 
and  similar  plants.  1-108".  In  xl.  25 
the  dorsal  aspect  of  the  jaws  is  repre- 
sented, and  in  26  their  frontal  aspect. 

Dr.  Dobie  writes  {A.N.H.  Oct.  1849)  : 
"  Ehrenberg  regards  the  Floscidaria  de- 
scribed and  figured  by  M.  Peltier,  as 
identical  with  his  F.  ornata.  Both  Du- 
jardui  and  Peltier  found  the  rotaiy  organ 
tive-lobed  in  the  species  observed  in 
France ;  so  we  must  either  hold  with 
Pritchard  that  F.  ornata  has  sometimes 
five,  at  others  six  lobes,  or  consider  the 
five-lobed  species  a  variety  of  F.  ornata. 
....  My  friend  Mr.  Hallet  writes  me  that 
he  finds  F.  ornata  -^-ith  a  six-lobed  ro- 
tary organ  and  no  process." 


The  two  next  species  and  accompanying  remarks  are  taken  from  a  paper 
by  Dr.  W.  M.  Dobie  {A.  N.  H.  Oct.  1849). 

F,    campanulata.  —  Case   diaphanous,  |  fringed  with  very  long  cilia ;  body  ovate, 
rotary   organ  with  five  flattened  lobes,  |  Tsnthout  proboscis ;  tail  long,  and  termi- 

2x2 


676 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


nating  abruptly  in  a  transparent  fila- 
ment, spread  out  in  a  kind  of  sucker 
at  the  point  of  attachment.  Length 
1-50"  when  extended.  Egg  with  two  red 
eye-spots;  contained  in  a  large  ovary. 
Found  near  Chester,  on  Ceratophyllum 
and  Confervas. 

F.  cornuta. — Case  short,  diaphanous, 
not  very  distinct ;  rotary  organ  furnished 


with  five  rounded  lobes,  surrounded  by 
extremely  long  and  delicate  cilia :  a  short, 
narrow,  non-ciliated,  flexible  process 
(cornu)  is  attached  to  the  outside  of  one 
of  the  lobes.  Egg  with  two  red  eye- 
spots  ;  yoimg  animal  with  vibratile  cilia 
on  the  head,  and  rapidly  locomotive. 
Length  1-40"  when  extended.  In  same 
locality  as  the  preceding  (see  woodcuts). 


Floscularia  cornuta,  Dobie. 

The  lobes  of  the  rotary  organ  of  F.  \  Leydig  has  described  a  Floscularia 
cornuta  resemble  very  much  those  of  under  the  name  of  F  appmdicuMa 
F.  ornata,  but  only  five  exist,  while  in  |  {Zeitschrift  fiir  ivissenschaftltche  Aoologie, 
the  other  there  are  six.  According  to  |  July  1854).  Mr.  Gosse,  however^ believes 
Ehrenberg  the  F.  campanulata  is  gre-  |  this  to  be_  identical  with  the  t.  cornuta 
garious,  whilst  F.  cornuta  is  solitary  ;  the  i  of  Dr.  Dobie. 
former  is  also  stronger  and  is  more  active 
than  the  latter.  '  ' 


OF  inE  HYDATIJJf^A.  677 


FAMILY  v.— HYDATINJEA. 


Illoricated  Rotifera,  having  the  ciliated  wreath  divided  into  several  lobes 
or  subdivisions. 

In  many  of  the  genera  distinct  striated  muscles  of  the  voluntary  type  exist, 
effecting  the  various  movements  and  altering  the  form  of  the  body.  The 
nutritive  system  usually  consists  of  a  simple  conical  ahmentary  canal  without 
a  distinctly  separated  stomach  (Coelogastrica)  ;  but  a  pyloric  constriction  exists 
in  Hydatina,  some  Notommatce,  and  other  forms.  Notommata  davulata  and 
Diglena  lacustris  have  special  caeca  appended  to  their  stomachs.  Yaiiously 
modified  cellular  appendages,  supposed  to  be  glandular,  exist  in  aU  the  genera. 
The  ovarium  is  mostly  ovate  and  only  evolves  a  few  ova  at  a  time.  In 
Notommata  Myrmeho,  N.  davulata,  and  Diglena  lacustris  it  is  very  long.  In 
all  it  communicates  with  the  cloaca,  by  an  oviduct  of  varying  length.  The 
ova  vary  considerably,  and  belong  to  two  distinct  types,  respectively  termed 
the  summer  and  winter  ova.  The  former  have  a  smooth  shell,  and  are  gene- 
rally regarded  as  mere  unimpregnated  gemmae,  like  those  of  Aphides  amongst 
insects.  The  latter  are  hard,  and  often  spinous,  in  which  form  M.  Tarpin 
regards  them  as  constituting  the  genera  Bursella  and  Erithrinella  (?)  amongst 
plants.  It  is  amongst  the  members  of  this  group  that  many  of  the  interesting 
researches  of  Daliymple  and  others  have  been  made,  demonstrating  the  exist- 
ence of  dioecious  animals.  Amongst  the  Rotifera  the  male  animals  of  Hydatina 
and  Asplandina  are  distinct  from  the  females.  They  are  generally  character- 
ized by  their  smaller  size  and  by  the  absence  of  digestive  organs — indicating 
a  brief  existence,  during  which  the  vis  vitce  derived  from  the  ovum  suffices  to 
sustain  the  animals  in  ful filing  their  several  functions.  According  to  Cohn, 
this  absence  of  an  alimentary  canal  in  the  males  does  not  characterize  the 
male  of  Notommata  parasitica  (XXXIX.  8) ;  but  this  is  so  exceptional  to 
aU  other  allied  discoveries  as  to  suggest  a  doubt  of  its  correctness :  at 
the  same  time,  we  have  scarcely  crossed  the  threshold  of  this  inquiry,  and 
want  the  materials  for  general  conclusions.  Water-vascular  canals,  variously 
modified,  exist  in  most  of  the  Hydatinsea.  The  frequent  association  of  the 
red  "  eye-spots"  with  a  subjacent  organ,  supposed  to  be  a  cerebral  ganglion, 
suggests  sensational  functions  ;  but  no  true  nerves  occur. 

Some  species  of  Synchceta  are  said  to  evolve  light  and  contribute  to  the 
phosphorescence  of  the  sea.  Hydatina  senta,  Diglena  catellina,  and  Triarthra 
are  sometimes  so  numerous  as  to  render  the  pools  in  which  they  reside  milky 
and  turbid. 

Ehrenberg's  classification  of  this  family  is  given  at  p.  478,  Section  Soro- 
trocha,  Division  Polytrocha. 

The  first  genus  (EXTEROPLEA),  established  to  receive  E.  hyalina,  has 
been  shown  by  Leydig  to  have  no  existence,  as  the  above  animalcule  proves 
to  be  the  male  of  Hydatina  senta. 

Genus  HYDATINA  (XXXII.  394 ;  XL.  1,  2).— Eyes  absent.  The  female 
has  two  jaws,  consisting  of  several  teeth  and  a  forked  foot.  Locomotion  is 
effected  by  the  compound  wheel  organ  and  the  pincer-like  foot,  acted  upon 
by  complex  internal  muscles.  In  Hydatina  senta  the  sexes  are  distinct,  the 
Eftiteroplea  hyalina  being  the  male  form. 


Hydatina  senta  (  Vorticella  senta,  M.) 
(xxxii.  394 ;  xl.  1).— Body  of  the  female 
conical,  hyaline  ;  rotary  organ  consisting 
of  a  simple  external  wreath  of  cilia  sm-- 
rounding  the  truncate  anterior  extremity 
of  the  Dodv,  and  enclosinof  at  the  back 


part  of  the  head  an  interrupted  row  of 
tufts  of  cilia  supported  on  small  hemi- 
spherical projections, — the  cilia  of  the 
latter  broader  and  longer  than  those  of 
the  external  row.  Within  these  is  a 
third  uninterrupted  line  of  cilia.     Neck 


678 


SYSTEMATIC  HISTOKY  OF  THE  TNFTJSOHIA. 


constricted  and  tlirowai  into  folds  or 
wrinkles  by  transverse  tilamentous 
muscles,  hung  like  hoops  within  the 
integument,  to  which  Cohn  believes 
them  attached  only  by  a  few  interrupted 
points.  These  muscles  were  regarded  by 
Ehrenberg  as  vessels.  The  contractile 
influence  of  these  and  similar  muscles 
occup}^ng  the  lower  parts  of  the  body  is 
antagonized,  according  to  Leydig,  by  the 
elasticity  of  the  cuticle,  but  according  to 
Cohn  by  the  pressure  of  the  compressed 
fluids  of  the  body.  Longitudinal  con- 
traction of  the  body  effected  by  nume- 
rous muscles  proceeding  from  the  head 
backwards  to  the  centre  of  both  sides  of 
the  body  and  thence  to  the  foot.  Ehren- 
berg counted  nine,  which  number  Cohn 
regards  as  correct.  The  latter  observed 
A  acuoles  and  what  appeared  to  be  nuclei 
in  the  substance  of  the  muscles,  but  no 
transverse  strise.  Two  bodies  at  the  base 
of  the  toes  Ehrenberg  regarded  as  muscles 
moving  those  organs ;  but  Cohn  believes 
them  to  be  glandular,  secreting  an  ad- 
hesive fluid  by  which  the  creatiu'e  at- 
taches itself  to  other  bodies. 

Digestive  canal  consisting  of  an  oral 
orifice  (xl.  1  a),  buccal  cavity,  pharyn- 
geal bulb  (1  c),  oesophagus  (1  d),  stomach 
(1  e),  intestine  terminated  by  a  cloacal 
orifice  at  If,  and  gastric  glands.  The 
buccal  cavity  a  short  passage  from  the 
mouth  (la)  (located  on  one  side  of  the 
head)  to  the  pharjTix  (Ic),  which  is  large  j 
and,  according  to  Cohn,  a  muscular  mass 
invests  the  jaws,  which  are  complex 
and  not  easily  interpreted,  but  consist  of 
several  parallel  teeth  (xxxviii.  34)  ar- 
ranged in  two  sets  and  attached  to  a 
complicated  pp'iform  organ:  respecting 
the  details  of  their  form,  authors  differ. 
A  constricted  passage  (1  d)  conducts  from 
the  phai-jTix  to  the  stomach  (1  e),  which 
is  large  and  oblong ;  its  walls  are  saccu- 
lated, or  expanded  into  numerous  lateral 
pouches  or  pockets  opening  into  the 
cavity  of  the  stomach,  the  whole  lined 
by  delicate  cilia  (xl.  4).  A  narrow 
pvlorus  separates  this  organ  from  a  short 
conical  intestine,  the  narrow  extremity 
of  which  temiinates  at  the  cloaca  (1/ ), 
opening  near  the  posterior  extremity  of 
the  body  on  the  opposite  side  to  that  on 
which  the  mouth  is  situated ;  two  large 
pyriform  bodies,  supposed  to  be  glan- 
didar,  are  suspended  by  narrow  peduncles 
on  each  side  of  the  phaniix. 

Connected  with  the  cloaca  is  a  large 
contractile  vesicle  (1  (/),  from  which 
ascend  two  water- vascular  canals  (1  i), 
convoluted  at  intervals  and  giving  off 


small  twigs  which  support  tremulous 
tags  (xE.  5).  Ovarium  a  large  pja-iform 
sac  (1  h),  connected  with  the  cloaca  by 
a  narrow  oviduct ;  it  consists  of  a  thin 
membrane  distended  by  a  granular  fluid, 
in  which  are  seen  numerous  genninal 
spots.  A  small  body,  supposed  to  be  a 
cerebral  ganglion  (Ik),  is  situated  on 
one  side  of  the  oesophagus,  and  is  con- 
nected with  a  small  setigerous  gi'oove  on 
one  side  of  the  neck  by  what  Cohn  be- 
lieves to  be  nerves.  Male  :  The  Mite- 
rojjlea  hydcdina  (xxxii.  393 ;  xl.  2)  of 
Ehrenberg  has  been  demonstrated  by 
recent  researches  to  be  the  male  of  Hy- 
dcdina senta.  Like  that  of  many  other 
species  it  has  no  visible  digestive  canity : 
in  general  form  it  closely  resembles  the 
female,  but  is  much  smaller.  Its  repro- 
ductive organs  consist  of  a  retractile 
penis  (xl.  0«),  enclosed  in  a  fold  of  the 
cuticle  (()  d),  the  opening  of  which  cor- 
responds with  that  of  the  cloaca  in  the 
female ;  the  base  of  the  penis  is  sur- 
rounded by  a  gland  (6  b),  above  which 
is  the  large  oblong  testicle  containing 
spermatozoa,  by  the  side  of  which,  at  its 
lower  part,  are  two  small  vesicles  (6  c), 
connected  with  the  penis,  and  filled  -svith 
numerous  large  granules,  xl.  3  repre- 
sents an  immature  ovum  of  Hydatina 
senta,  and  fig.  7  the  detached  spenna- 
tozoa  from  the  male  animal. 

In  most  cases  the  female  fixes  itself  to 
a  spot  by  its  foot,  and  lays  several  eggs 
upon  the  same  place,  one  after  another, 
by  sudden  contractions  ;  sometimes, 
when  it  is  going  to  lay  more  eggs,  it 
returns  to  the  original  spot.  In  eleven 
hom\s  after  the  eggs  were  laid,  vibration 
of  the  anterior  cilia  was  observed,  by 
Ehrenberg,  within  them ;  and  in  twenty- 
four  hours  the  young  escaped  from  the 
shell.  Many  of  the  ova  are  said  to  have 
a  double  shell,  and  leave  a  bright  space 
between  the  two  at  one  of  the  extremi- 
ties; similar  ova  are  found  in  other  Eota- 
toria,  ha\dng  different  shapes.  In  these 
double-shelled  ova  the  young  are  slowly 
developed.  Ehrenberg  names  them  ^'  last- 
ing eggs,  or  Avinter  eggs."  xxxn.  394 
represents  an  animal  completely  imfolded, 
seen  from  the  ventral  siu-face.  The  an'ows 
in  the  alimentary  canal  indicate  a  de- 
cussating or  circulating  movement  of  its 
contents,  produced  by  delicate  internal 
cilia,  and  must  not  be  mistaken  for  the 
motion  of  Monads. 

H.  hrachydactyla.  —  Cylindrical,  trun- 
cated anteriorly,  and  suddenly  attenu- 
ated at  the  base  of  the  foot ;  claws  short. 
On  Hottonia,  &c.     1-144". 


OF  THE  HYDATIN^A.  679 

Dujardin  would  include  in  the  genus  ffydatina  several  Eotatoria  distributed 
by  Elii'enberg  among  other  genera.  He  says  :  "  Notrdthstanding  the  presence 
of  a  red  eye-speck,  we  must  consider  as  Hydatinae — 1.  Notommata  tuba  ; 
2.  N.  brachionus ;  3.  N.  trijpus  ;  4.  N.  davxdata,'^  and,  though  doubtfully,  N. 
saccigera,  for  this  species  in  form  resembles  a  true  Furcularia.  "■  The  Syn- 
chcetce  (Ehr.),  characteiized  by  theii'  stiff  setae  or  styles,  are  true  Hydatinae 
from  their  conical  or  campanulate  form,  if  theii'  jaws  are  really  pectinated; 

but  if  not,  they  will  constitute  a  genus  apart The  Distemma  maximum, 

represented  by  Ehrenberg  with  pectinated  jaws,  and  placed  as  doubtful  by 
him  in  the  genus  Distemma,  characterized  by  a  double  eye-speck,  appears  to 
be  a  tnie  Hydatina.'^^ 

Genus  PLEUEOTROCHA  (XXXII.  395,  396).— These  have  no  eyes,  but 
possess  a  single  tooth  in  each  jaw,  and  a  furcate  foot.  The  rotary  organ  con- 
sists, not  of  a  simple  wreath  of  cilia,  but  of  cilia  distributed  in  bundles  near 
each  other,  the  bundles  being  planted  in  muscular  cases.  In  P.  gibha  there  are 
two  muscles  for  moving  the  foot ;  and  in  aU  the  species  the  globular  oesophageal 
head  has  four,  acting  upon  two  single-toothed  jaws  (fig.  396) ;  oesophagus 
short ;  alimentary  canal  simple,  conical,  having  anteriorly  two  spherical  glands. 
The  anus  is  at  the  base  of  the  foot,  upon  the  dorsal  surface.  The  ovary  is 
globular.  In  P.  leptura  a  contractile  vesicle  is  seen.  Organs  of  sensation 
are  not  satisfactorily  known,  and  the  nervous  loop  in  the  neck  of  the  ffydatina 
appears  wanting.     This  genus  is  not  admitted  by  Dujardin. 

PLEunoTROCHA    g/bbci.  —  Truncated  i  animalcule  is  very  active  and  powerfid. 
anteriorly,  enlarging  from  the  front  to-  |  Upon  Ceratophyllum.     1-144". 
wards  the  base  of  the  foot,  where  it  is  i      F.leptura. — Body  turgid  in  centi-e,  front 
suddenly  attenuated,  the  toes,  or  claws, 
short  and  turgid ;  near  the  mouth  is  a 
beak-like  projection,  forming  an  under 
lip.     XXXII.  .395  is  a  right  side  view; 
396  the  teeth  and  oesophageal  head  dis- 
sected out.     Found  with  ffydatina  bra- 
chydactyla.     1-216". 

P.  constricta.  —  Elongated,  conical, 
head  separated  by  a  stricture ;  front  ob- 
lique; toes  straight  and  slender.     This 


oblique ;  foot  slender ;  toes  thin,  shghtly 
curved.     iVmongst  Conferv^ae.     1-144". 

P.  renalis  (Ehr.). — Elongate,  slightly 
constricted  in  front,  toes  short,  frontal 
portion  rather  oblique,  ti'uncate,  pan- 
creatic glands  kidney-shaped  (reniform). 
1-240".     Berlin. 

P.  truncata  (Gosse). — Subcylindrical ; 
truncate  behind  above  the  foot ;  toes 
short,  straight,  slender.     1-175". 


Genus  FUECULAEIA  (XXXIII.  397,  398).— Frontal  eye  single;  foot 
forked.  Eotary  organ  compound.  Longitudinal  muscles  exist  in  F.  gibba, 
and  foot-muscles  in  three  species.  The  oesophagus  is  very  short,  its  head  has 
two  jaws,  single-toothed  (Monogomphia)  in  two  species,  but  not  in  the  others  ; 
alimentary  canal  simple  (Coelogastrica),  conical,  with  two  ear-like  glands ; 
ovary  distinct,  except  in  F.  gibba,  which  has  only  a  contractile  vesicle. 
Vessels,  respiratoiy  tubes,  gills,  &c.,  are  not  recognizable.  The  eye  in 
F.  Reinhardtii  is  placed  upon  a  brain-like  mass. 

Dujardin  has  the  following  remarks  on  the  genus  Furcidaria  : — '^  The 
genus  Furcidaria,  one  of  the  most  numerous,  undoubtedly  requii^es  to  be 
divided  after  new  observations,  but  not  according  to  the  number  and  dis- 
position of  the  red  points,  as  has  been  done  by  Ehrenberg.  This  author  has 
indeed  distributed  some  Systolides,  which  appear  to  us  to  have  the  closest 
relations  in  form  and  mode  of  hving,  into  eight  genera  "  (viz.  Pleurotrocha, 
Furcularia,  Notommata,  Scaridium,  Dighna,  Distemma,  Eosplio^^us,  and 
Theorus) ;  ^'  but  many  of  these  are  purely  nominal,  and  require  a  rigid 
revision. 

''  The  following  are  the  principal  species  to  be  classed  with  certainty  among 


680 


SYSTEMATIC  niSTORY  OF  THE  INFUSORIA. 


the  Furcularice  : — 1.  F.  furcata=Diglena  caudata  (Ehr.),  Diglena  capitata, 
and  Furcidaria  gracilis ;  2.  F.  marina,  of  the  same  size  and  form  as  the 
preceding,  but  marine,  and  distinguished  fui^ther  by  the  styles  of  its  tail, 
which  are  twice  as  short,  and  by  its  three-toothed  but  acute  jaws,  resembling 
a  hook ;  3.  F.  forcipata,  placed  by  Ehi^enberg  among  the  Diglenoe ;  4.  F. 
grandis= Diglena  grandis  (Ehr.);  5.  F.  forficida,  with  which  must  also  be 
associated  Distemma  foi^Jicula  ;  6.  F.  canicida,  which  Ehrenberg  with  doubt 
refers  to  Diglena  ?  aurita ;  7.  F.  najas,  to  which  belong  the  various  Systo- 
lides,  more  or  less  hke  Hydatina  in  their  club-shaped  form  and  articulated 
tail,  such  as  Notommata  petromyzon,  N.  najas,  N.  gihha,  and  probably  also 
Eospliora  najas,  E.  digitata,  and  E.  elongata  (Ehr.).  We  moreover  refer 
provisionally  to  the  genus  Furcidaria  several  other  Systolides  considerably 
dissimilar  in  form,  some  being  very  long,  with  two  very  long  styles,  of  which 
Ehrenberg  makes  his  Notommata  longiseta,  and  N.  ceqiialis,  and  his  genus 
Scaridium;  whilst  others  have  an  ovoid,  thick  body,  rounded  posteriorly, 
truncate  in  front,  and  with  a  short  oblique  tail,  which  Ehrenberg  calls 
Notommata  myrmeleo  and  N.  syrinx, 

"  All  these  Furcidaiice,  except  F.  marina,  to  which  F.  Reinhardtii  of  Ehren- 
berg must  probably  be  added,  have  been  foimd  in  fresh  water ;  but  it  is  most 
likely  the  number  of  those  living  in  the  sea  are  much  more  numerous ;  and  I 
have  indeed  myself  met  with  three  or  four  distinct  species,  which  I  have 
from  want  of  time  not  yet  described," 


FuRcrLARiA  gihha. — Oblong,  slightly 
compressed,  under  side  flat,  back  convex, 
toes  forked,  long  (styliform),  equal  to 
half  the  body ;  the  eye  is  placed  upon  a 
nervous  ganglion  over  the  mouth,  clearly 
indicating  the  dorsal  sm-face;  the  ova- 
rium has  generally  one  large  and  ripe 
ovum.  The  movement  of  this  animal- 
cule is  somewhat  slow.  Found  in 
green  water,  and  amongst  Confervse. 
1-69". 

F.  jReinhardtii.  —  Fusiform,  truncated 
in  front ;  foot  elongated,  cylindrical,  and 
shortly  furcate  at  the  end ;  a  slight 
stricture  divides  the  body  and  head. 
XXXIII.  397  represents  an  animal  ex- 
tended, and  398  another,  contracted  ; 
the  former  is  a  side  (right),  the  latter  a 
back  view.     Parasitic  upon  Monopyxis 


(Sertularia)  qenicidata,  in  sea-water. 
1-120". 

F.  Forjicida,  —  Cylindrical,  obtusely 
pointed  in  front,  rounded  and  dentated 
at  the  base,  on  the  upper  side ;  the  toes 
very  long ;  the  rotary  organ  appears  to 
have  two  frontal  clusters  of  cilia  near 
the  eye,  and  a  wheel-like  bundle  on 
each  side.     1-144". 

F.  gracilis. — Slender,  cylindrical,  sud- 
denl}^  attenuated  at  the  base  of  the 
furcate  foot;  toes  straight,  long,  but 
shorter  than  half  the  body.  The  rotary 
organ  appears  disposed  on  six  muscular 
masses. 

F.  C(eca  (Gosse).  —  Cylindrical ;  eye 
wanting,  or  not  discernible  ;  toes  slender, 
obtuse.  Length,  including  toes,  1-135". 
Learning-ton. 


Genus  MOXOCERCA  (XXXIII.  399-417).— Eye  single,  seated  upon  a 
ganglionic  mass,  conical ;  foot  simple,  styliform,  resembling  a  tail.  In  two 
species  the  vibratile  cilia  are  distributed  into  about  six  bundles,  their  band-like 
longitudinal  muscles  and  those  of  the^  foot  producing  locomotion ;  the  sides 
of  the  oesophageal  head  are  unequal,  as  also  the  two  jaws,  which  have  one  or 
two  teeth  ;  the  oesophageal  tube  is  curved  and  long,  and  the  simple  alimentary 
canal  conical,  mth  two  ear-like  glands  anteriorly.  An  ovary  and  a  con- 
tractile vesicle  are  evident.  In  two  species  a  tube  projects  from  the  frontal 
region. 


MoxoCERCA  Rattus  (Trichoda  Raftus, 
M. ;  Rattidiis  carinatus,  Duj.). — Ovate, 
obong,  truncated  anteriorly,  and  im- 
armecl ;  foot  styliform,  the  length  of  the 
bodv.     This  creature  swims  slowlv,  in  a 


stiff'  manner ;  when  stationary  it  throws 
the  styliform  foot  backwards  and  for- 
wards.' The  ovary  has  a  reddish  coloui'; 
behind  it  hes  a  roundish  contractile 
vesicle.     The  foot  has  a  short  base,  with 


OF  THE  Hi'DATIXJEA.  681 

a  cordate  internal  muscle,  and  foiu'  im-  I  during  contraction,  shows  four  muscular 
equal  bristles.  Amongst  Confervse,  &c.  .  sheaths;  and  the  distinct  red  eye  is  placed 
1-120".  upon  a  less  distinct  ganglion;  the  oeso- 

Mastigocerca  carinata  is  regarded  by  phageal  head  is  not  evident.  1-288". 
Perty  and  Dujardin  as  identical  with  M.  hrachyura  (Gosse). — Form  that  of 
Monocerca  Rattus.  Dujardin  identifies  iJf.  i2«if/'«/s,  but  the  foot  short  (one-fourth 
AA-ith  this  an  animal  he  discovered  and  of  total  length),  slightly  curved,  and 
figured  (xxxviii.  22),  measuring  0*147  '  horizontally  flattened  ;  a  large  eye  in  the 
niillim.,  or  with  its  tail  0-29  millim.  j  occiput,    and   another  small   one   in   the 

M.  bicornis. — Ovate,  oblong,  trimcated  breast.  Length,  including  foot,  1-185". 
in  front,  armed  with  two  spines ;  foot  M.  Porcellus. — Thick  and  plump  ;  foot 
styliform,  a  little  shorter  than  the  body ;  short,  much  curved  and  bent  imder  the 
the  oblique  oesophageal  head  exhibits  body,  dilated,  flattened  liorizontally,  and 
delicate  transverse  corrugations  ;  it  has  carrying  a  smaller  spine  beneath  it  as  in 
a  bent  and  a  straight  jaw,  \\dth  probably  !  a  sheath  ;  front  and  chin  each  armed 
three  teeth  in  each,  (xxxiii.  399,  an  |  with  a  short  shai-p  spine.  Length,  in- 
animal  seen  on  its  right  side ;  417  an-  \  eluding  foot,  1-110". 
other,  contracted,  and  having  its  rat-  j  M.  stylata.  —  Short,  iiTegiilarly  oval ; 
like  tail  bent.)     1-72".  I  foot  a  nearly  straight  spine,  less  than 

M.  (?)  xalcia  (  Vorticella  valf/a,  M.). —  i  one-third  of  total  length  ;  eje  large,  red, 
Small,  almost  cubical,  ^\ath  distinct  head,  set  like  a  wart  on  the  back  of  the  occi- 
au  elevation  on  the  back,  and  a  conical  j  pital  sac  ;  forehead  conical,  pointed, 
foot  unequally  forked ;  the  rotaiy  organ,  i  Length,  including  foot,  1-170". 

Genus  XOTOM^^IATA  (XXXIII.  416-421 ;  XXXYI.  3-6 ;  XXXYII. 
27-32 ;  XXXYIII.26  ;  XXXIX.  8,  9).— These  have,  according  to  Ehrenberg, 
a  single  eye  upon  the  neck,  and  a  bisulcate  foot,  resembling  a  forked  tail. 
The  rotary  organ  compound,  its  cilia  forming  bundles  on  the  frontal  region. 
Eight  of  the  larger  species  have  numerous  muscles.  Of  Ehrenberg's  species 
eighteen  or  nineteen  have  two  jaws,  each  furnished  with  a  single  tooth ;  in 
eight  the  jaws  have  many  teeth.  The  oesophagus  is  mostly  short,  with  a 
simple  wide  conical  alimentary  canal  (Coelogastrica) ;  in  N.  tuba  only  is  there 
a  stomach-like  division,  mth  a  constriction  (Gasterodela) ;  and  in  N.  Myr- 
meleo,  N.  Syrinx,  and  N.  davidata  there  is  also  a  stomach-like  enlarged 
place,  but  no  constriction  (Gasterodela)  :  caecal  appendages  are  observed  only 
in  N.  davulata.  The  two  ear-like  anterior  appendages  of  the  alimentary 
canal,  regarded  by  Ehrenberg  as  pancreatic  glands,  exist  in  twenty-fom- 
species.  N.  Syrinx  alone  was  observed  by  Ehrenberg  to  contain  fully- 
developed  ova.  The  water-vascular  system  is  represented  in  ten  species  by 
delicate  tubes,  with  flexible  and  tremulous  gills ;  only  three  of  the  smaller 
species  have  gills.  In  iV.  Myrmeleo  and  N.  Syiinx  a  broad  vascular  network 
is  distinct  about  the  head.  A  prominent  tactile  tube  in  the  neck  is  present 
in  four  or  five  species ;  in  some  others  an  opening  alone  is  seen.  The  visual 
point  is  red,  except  in  N.  Felis,  where  it  is  colourless ;  a  ganglion  is  placed 
beneath  the  eye  in  twenty-six  species.  In  A^.  Copeus  and  N.  centrura  the 
brain  (?)  is  three-lobed,  and  placed  over  the  oesophageal  head  ;  in  the  rest  it 
consists  of  one  or  more  nervous  ganglia,  situated  amongst  the  ciliary  muscles 
of  the  frontal  region.  This  genus  is  especially  remarkable  for  the  parasitical 
habits  of  its  members.  They  live  upon  other  Rotatoria,  upon  the  Polygastrie 
Infusoria,  and  even  within  the  globular  masses  of  Volvox  Globator ;  "  but," 
says  Ehrenberg,  ''  not  like  a  cuckoo's  eg^  in  a  hedgesparrow's  nest,  but  like 
the  bear  and  the  bee-hive,  or  a  bird's  nest  in  a  wasp's  nest." 

Dujardin  has  the  following  criticisms  on  this  genus  : — "  Five  of  the  species 
appear  to  be  Hydatince;  nine  others,  more  or  less  distinct,  are,  in  our  opinion, 
Fiircidarice ;  three  others  PJagiognatlii ;  some  are  imperfectly  known ;  and 
only  six,  at  most,  ofiPer  suiRciently  precise  characters  to  retain  the  name 
Eotommata.     Such  are,  1.  N.  copeus,  2.  N.  centrura,  3.  N.  brach/ota,  4.  N. 


682 


SYSTEMATIC  HISTOET  OF  THE  INFUSORIA. 


collarls,  5.  N.  aurita,  and  6.  N.  ansataJ'  To  these  species  must  be  added 
a  seventh,  called  by  Ehrenberg  Cycloglena  Lupus,  and  an  eighth,  which  we 
distinguish  as  Notommata  vennicularis. 

All  the  best  observers  agree  that  the  genus  Notommata  requires  division, 
being  a  very  defective  one,  and  containing  the  elements  of  several  genera ; 
but  all  the  siDecies  now  composing  it  must  be  subjected  to  a  very  careful  and 
individual  examination  before  such  a  division  can  be  made.  Until  this  is 
accomplished  we  retain  the  genus  as  adopted  by  Ehrenberg,  observing  that 
the  analysis  of  Ehrenberg's  views  respecting  it,  as  given  in  a  preceding  page, 
will  ultimately  require  many  modifications.  Some  species  have  already  been 
carefully  investigated  by  Gosse,  Perty,  and  Leydig. 


a.  Subgenus  Labidodon. 

Notommata  Myrmeleo. — Body  large, 
bell-shaped;  foot  short,  lateral;  teeth 
cm*ved  in  a  circular  forceps-like  manner 
(xxxin.  420).  There  are  two  varieties : 
in  the  one  (var.  a),  a  long  thin  oesopha- 
gus, a  globular  thick  stomach,  and  a  long 
rec^um  constitute  the  alimentary  organs. 
Ehrenberg,  by  pressure,  made  an  ani- 
malcule, whose  dark  stomach  nearly 
hlled  the  body,  disgorge  two  large  spe- 
cimens of  Lijnceus  minuttis  (described 
and  figured  in  the  Microscopic  Cabinet)  ; 
the  animalcide  afterwards  vibrated  away 
in  a  lively  manner.  Five  transverse  mus- 
cular bands  and  four  longitudinal  ones 
(a  pair  uniting  to  each  of  the  first  two 
transverse  ones)  represent  a  muscular 
system  in  this  variety.  In  the  other 
(var.  h),  a  distinct  muscular  network  is 
seen  at  the  head,  but  only  four  trans- 
verse bands  and  two  longitudinal  ones 
going  to  the  first.  The  red  eye  is  much 
larger  in  this  variety,  (xxxiii.  418,  a 
side  view  of  the  variety  h :  to  exhibit  its 
organization,  a  small  Crustacean  is  shown 
within  its  stomach.  Fig.  420,  the  man- 
ducatory organs  separated ;  fig.  419,  the 
upper  part  of  an  animalcule,  var.  a,  show- 
ing the  smaller  eye,  rotary  organs,  teeth, 
and  network.)  Found  in  clear  water,  in 
turf-hollows.     1-40". 

Notomtnafa  Myrmeleo,  var.  midticeps, 
according  to  Leydig,  presents  the  follow- 
ing features : — The  foot,  which  on  a  pro- 
file view  appears  given  oft'  fioni  a  lateral 
surface,  projects  from  the  abdominal 
one.  The  rotary  organ  not  consisting 
of  separate  portions,  but  forming  a  con- 
tinuous ^a-eatli,  which  descends  towards 
the  mouth,  forming  an  apparent  fissure. 
On  the  free  surface  are  four  unsynnne- 
trical  lobes  bearing  larger  setiform  cilia. 
Cuticle  soft  and  thin,  slightly  acted  on 
by  acid,  which  renders  it  clearer ;  sub- 
jacent layer  granular  and  homogeneous. 
INIaxillary  head  very  large.  Oesophagus 
long,  thin,  folded  longitutinally.  Stomach 


— One  tooth  in  each  jaw. 

round,  with  ciliated  cells  :  no  rectmn 
beyond  the  stomach,  Ehrenberg  being 
in  error  on  this  point;  debris  rejected 
by  the  mouth.  A  respiratory  canal  pro- 
ceeds from  each  side  the  contractile  sac 
towards  the  head,  being  much  convo- 
luted and  enveloped  with  cell-like  cor- 
puscles ;  a  second  smaller  pair  follows 
a  similar  course,  joining  the  larger 
near  the  maxillary  bulb.  The  smaller 
have  not  granular  walls,  but  support 
numerous  tags,  which  are  absent  from 
the  larger  canals.  Two  bands  proceed 
backwards  from  the  cerebral  ganglion  to 
a  couple  of  foss8e  on  the  dorsal  surface, 
furnished  with  a  bundle  of  setse.  Eye- 
speck  dark-red  or  black.  Ovary  present- 
ing two  horns,  fonning  an  organ  like  a 
horseshoe,  the  oviduct  opening  at  the 
base  of  the  tail.  Winter  ova  spherical, 
bristly,  with  a  light  cortical  layer  con- 
taining clear  vesicles. 

N.  Syrinx. — Large,  bell-shaped ;  lateral 
foot  scarcely  visible ;  teeth  curved  and 
bifid  at  the  points.  This  species  is  very 
similar  to  the  former,  and  only  distin- 
guished from  it  by  its  small  foot  and 
by  the  spaces  within  the  cilia-cluster 
(mouth)  being  convex,  not  concave. 
Found  in  a  turf-pool.    1-40". 

N.  liyptopus. — Bell-shaped,  nearly  glo- 
bular, rather  large ;  foot  slightly  pro- 
minent at  the  middle,  teeth  small ;  vibra- 
tile  organ  composed  of  four  or  five 
muscular  bundles ;  cesophagus  very  short. 
1-72". 

N.  parasita  (xxxix.  9). — Small,  oval ; 
foot  short,  teeth  small;  rotary  apparatus 
three  or  four  lobes ;  oesophageal  head 
globose  ;  oesophagus  short ;  alimentary 
canal  stout,  simple,  usually  filled  with 
green  matter.  This  cniious  animalcule 
lives  in  the  globes  of  Volvox  Glohator, 
where  it  deposits  its  eggs,  which  are 
therein  hatched;  and  when  of  proper 
age,  the  creatures  eat  their  way  out 
through   the  hollow  sphere.      Summer 


OF  THE  HYDATIN^EA. 


683 


ova  large,  smooth  j  winter  ova  spinous. 
1-40". 

According  to  Cohn,  the  male  of  this 
species  (xxxix.  8)  is  a  small  Rotifer 
1-20"'  in  length.  Body  short  and  sac- 
cular ;  two  short  toes,  usually  retracted ; 
head  distinguished  by  a  slight  excava- 
tion, and  with  an  ear-like  lappet  on 
either  side ;  rotary  organ  furnished  with 
some  stout  uncini,  in  addition  to  the 
fine  cilia ;  pharynx  cj'lindiical,  contain- 
ing two  scalpel-like  teeth,  which  can  be 
extended  beyond  the  mouth;  stomach 
separated  from  the  mtestine  by  a  con- 
striction. A  contractile  vesicle  above  the 
foot,  but  water-canals  scarcely  visible. 
A  cerebral  ganglion,  resembling  a  long 
sac,  within  the  head,  and  bearing  a  red 
speck  at  its  anterior  extremity.  Males 
and  females  usually  existing  in  the  same 
Volvox.  We  have  considerable  doubts 
respecting  the  correctness  of  the  above 
accoimt,  since  it  diifers  so  widely  from 
what  has  elsewhere  been  observed 
amongst  such  male  animals  as  have 
hitherto  been  discovered  amongst  the 
Rotifera.  The  absence  of  a  complete 
alimentary  canal  has  hitherto  character- 
ized all  male  Rotifera.  (The  female  is 
represented  after  Cohn  in  xxxix.  9.) 

N.  petromyzon.  —  Elongated,  attenu- 
ated at  both  ends;  mouth  and  rotary 
organ  lateral.  Ehrenberg  says,  in  May 
1835  he  found  one  in  a  Volvox  Glohator, 
whose  gemmiferous  masses  it  eats  like 
N.  parasitica.  The  eggs  are  often  de- 
posited on  Epistylis.     1-180"  to  1-144". 

N.  lacinulata  \Vorticella  aiiriculata  et 
arcinulata,  M.).  —  Small,  conical,  trun- 
cated and  slightly  lobed  in  front ;  teeth 
extended,  often  bicuspid.  Alimentary 
canal,  according  to  Eeydig,  clearly  sepa- 
rable into  a  greenish  yellow  stomach 
and  a  clear  intestine.  This  species  is 
very  active.  Found  with  Chlarnidomonas 
Pulviscidus  in  clear  water,  also  in  water- 
tubs.     1-280". 

N.  forcipata. — Small,  elongated ;  toes 
long,  and  often  crossed ;  eye  very  large. 
The  vibratile  organ  appears  sometimes 
like  a  simple  wreath.  Amongst  Lemnae. 
Very  common  in  Switzerland,  according 
to  Perty,  but  with  a  small  red  eye-speck 
instead  of  a  large  pale  one,  as  described 
by  Ehrenberg.     1-180". 

N.  coUaris. — Elongated,  large,  gradu- 
ally attenuated  at  both  ends  ;  neck  tur- 
gid; toes  short.  It  swims  slowly,  the 
vibratile  organ  being  small  in  comparison 
vAih.  the  body.     1-48". 

N.  JVerneckii.  —  Elongated,  gi'adually 
attenuated  at  both  ends ;  toes  short.     It 


has  two  setae  near  the  mouth.  This 
animalcule  resembles  N.  coUaris,  but  is 
smaller,  and  lives  in  the  club-like  ex- 
crescences of  Vaucheria  as  an  entophyte. 
1-90". 

N.  Najas. — Conical,  cylindrical,  stout, 
truncated  in  front ;  no  auricles.  It  re- 
sembles Hydatina  senta  and  Eosphora 
Najas ;  it  is  distinguished  from  the  first 
by  its  cervical  eye,  from  the  latter  by  the 
want  of  frontal  eyes.  Amongst  Lemnae. 
1-120". 

N.  aurita  (xxxvi.  3-6). — Described  by 
Mr.  Gosse  as  cylindrical,  but  frequently 
pyriform.  Head  obliquely  trimcate,  belly 
nearly  straight,  posterior  extremity  pro- 
duced into  a  retractile  foot  (xxxvi.  4  h) 
with  two  pomted  toes,  which  organ, 
being  anterior  to  the  cloaca,  is  not  a 
tail.  An  oval  mark  on  each  side  of 
the  head,  from  which  the  animal  can 
suddenly  project  a  semiglobular  lobe 
by  evolution  of  the  integument  (xxxv^. 
4  a),  each  lobe  fringed  with  cilia,  form- 
ing a  locomotive  organ ;  fringe  of  cilia 
extending  across  the  front  of  the  face 
as  far  as  the  constriction  of  the  neck. 
Maxillary  bulb  or  gizzard  (4  h)  large, 
oval,  nearer  the  ventral  than  the  dorsal 
side,  having  imbedded  within  it  a  pair 
of  complex  jaws  (xxxvi.  6  *).  A  duct 
leads  from  the  maxillary  bulb  to  the 
continuation  of  the  alimentary  canal, 
which  is  wide,  subcylindrical,  tapering 
towards  the  anus,  not  divided  by  any 
constriction,  but  at  once  stomach  and 
intestine ;  walls  thick,  probably  cellular. 
Cloaca  between  the  projecting  point 
(xxx\^.  3)  and  the  foot.  Ovary  large, 
occuppng  the  ventral  region ;  some- 
times long  and  clear,  containing  trans- 
parent globules  (4/),  at  others  gra- 
nulated (xxx\i.  3),  A  large  developed 
G,^^  (4  o)  often  occupying  a  gi-eat  por- 
tion of  the  abdominal  ca^-ity.  Eggs  large, 
covered  with  short  flexible  spines.  Male 
unkno-wTi.  Water-vascular  system  con- 
sisting of  two  sets  of  tortuous  vessels, 
commencing  at  the  cloaca  (6  «)  and 
terminating  at  the  head,  and  bearing 
tremulous  tags.  Parallel  with  the  oeso- 
phageal bulb,  but  nearer  the  dorsal  sur- 
face, is  a  large  lobulated  subglobose 
mass  of  dense  matter  (4  y),  white  by 
reflected  light,  but  opaque  and  hence 
appearing  black  by  transmitted  light, 
occupying  the  bottom  of  a  deep  cylin- 
drical sac.  A  tube  runs  through  the 
centre  of  this  sac  towards  the  rotary 
organ,  "on  which  it  opens,  or  at  least 
impinges "  (Leydig).  As  this  opaque 
mass  supports  the  eye-spot,  Gosse  re- 


684 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


gards  it  as  cerebral.  Muscular  system 
complex  (xxxvi.  5,  6).  Six  or  seven 
muscles  are  circular  and  transverse 
(6 1)  ;  others,  arranged  longitudinally 
(5/),  are  attached  to  various  internal 
viscera  and  to  the  integument.  Some  go 
to  the  occipital  sac,  others  to  the  gizzard 
and  to  the  foot,  effecting  various  motions 
in  all  these  organs.  Gosse  observes,  ''  It 
commonly  keeps  the  ear-like  lobes  con- 
cealed whilst  crawling,  but  will  often 
suddenly  protrude  them,  and  in  the  same 
instant  shoot  off  through  the  water  with 
considerable  rapidity  and  with  a  smooth 
gliding  motion,  partially  revolving  on 
the  longitudinal  axis  as  it  proceeds." 

Leydig  observes  that  the  alimentary 
canal  consists  of  two  portions — stomach 
and  intestine.  1-70".  Amongst  Con- 
fervse,  &c. ;  also  beneath  ice.  (xxxvi. 
3-7.) 

N.  gihha. — Back  swollen,  front  trun- 
cated, not  auricled,  no  cerebral  sacculi 
below  the  eye :  toes  short ;  the  -vdbratile 
organs  compound.  In  old  exposed  in- 
fusions.    1-200". 

N.  ansata  ( Vorticella  aurita,  M.).  — 
Turgid  in  the  middle,  suddenly  trun- 
cated at  both  ends ;  the  front  auricled, 
no  cerebral  saccidi  below  the  eye ;  toes 

b.  Suhge7ius  Cteis'ODOK 

N.  clanilata. — Bell-shaped ;  foot  coni- 
cal, very  short;  pancreatic  glands  of  a 
club-shape.  This  creature  presents  great 
facility  for  observing  its  internal  struc- 
ture ;  but  the  limits  of  this  work  preclude 
details.  Mr.  Gosse  kindly  informs  us 
that  he  has  distinctly  seen  in  it  a  nor- 
mal intestine  terminating  in  the  cloaca. 
1-96". 

N.  Tuba.  —  Conical,  trumpet-shaped, 
dilated  anteriorly  ;  foot  furcate  and 
acute.  It  resembles,  in  form,  Stentor 
Mulleri,  but  is  more  active.     1-120". 

N.  Brachionus. — Dilated,  nearl}^  square, 
depressed,  foot  slender,  eggs  pendulous. 
This  creature  appears  to  have  a  shell, 
but  Dr.  E.  says  it  has  not.  Ehrenberg 
described  his  N.  granulans  as  depositing 
its  eggs  upon  N.  Brachionus,  whence  he 
concluded  that  the  former,  like  the 
cuckoo,  left  its  young  to  be  reared  by 
another  creature.  He  found  that  some  of 
the  eggs  on  the  dorsal  surface  of  N.  Bra- 
chionus produced  N.  granularis.  Leydig 
solves  the  mystery  by  affirming  that  the 
latter  species  is  the  male  of  the  former, 
the  animal  in  this  case  being  bisexual, 
not  hermaphrodite.     1-96". 

N.  tripas.  —  Oval,  subtruncated,  and 
slightly  auricled  in  front.    Dark  red  eye- 


thick.  In  bog- water,  amongst  Confervae. 
1-120". 

N.  decipiens.  —  Cylindrical,  not  au- 
ricled; toes  short;  the  ovarium  often 
contains  four  large  eggs.  Perty  thinks 
this  is  only  the  young  of  some  other 
species.     1-180". 

N.  (?)  Felis. — Small,  slender ;  one  horn 
in  front ;  eye  colourless ;  back  attenu- 
ated posteriorly,  and  forked.     1-240". 

N.  (?)  Tigns  {Trigoda  Tigris,  M.) 
(xxxiu.  421). — Cylindrical,  ciiiwed,  foot 
half  the  length  of  the  body ;  toes  very 
long,  and  curved  downwards;  it  has  a 
little  horn  in  fi'ont ;  the  eye  is  large  and 
red.  Perty  has  found  many  examples 
without  the  red  eye.  Amongst  Oscil- 
latoriffi.     1-72". 

N.  longiseta  {Vorticella  longiseta,  M.). 
— Cylindrical,  truncated  anteriorly ;  toes 
styliform,  unequal,  and  two  to  four  times 
longer  than  the  body.  It  is  active,  and 
frequently  leaps,  being  assisted  by  its 
long  claws,  which  resemble  tails.  Fig. 
421  is  a  full-gro^\^l  specimen.  Entire 
length  1-60". 

N.  cequalis  {Vorticella  longiseta,  M.). 
— Cylindrical,  obtuse  in  front ;  toes  sty- 
liform, equal  the  length  of  the  body. 
l-]20". 

— Jaws  many -toothed. 
speck  with  three  chalky  masses,  giving 
the  organ  a  trilobed  appearance.  Foot 
apparently  trifid,  but  not  really  so,  the 
central  lobe  being  only  the  prolonged 
back  of  the  animal.     1-200". 

N,  saccigera. — Elongated,  cylindrical, 
attenuated  posteriorly ;  fork  short.  It 
has  a  curious  internal  pouch  beneath  the 
eye,  with  a  gi'oup  of  rounded  vesicles 
in  front  of  the  stomach,  recalling,  as 
Perty  observes,  the  pretended  agglome- 
ration of  eyes  in  Theorus. 

N.  Copeus. — Large,  attenuated  at  both 
ends;  tail  small  and  indurated.  This 
curious  creature  has  a  long  bristle  on 
each  side  of  its  body ;  and  on  each  side 
of  the  head  a  stout  process,  called  by 
Ehrenberg  an  auricle,  fringed  with  vibra- 
tile  cilia  at  its  ends,  and,  like  the  setse, 
standing  out  at  right  angles  to  the  body ; 
a  thick  gelatinous  substance  covers  the 
body;  the  back  terminates  in  a  some- 
what hard  point,  which  is  a  true  tail, 
between  which  and  the  foot  the  dis- 
charging opening  is  situated.  When 
creeping,  the  large  vibratile  arms  are 
withdrawn,  but  it  vibrates  with  the 
frontal  cilia  and  proboscis,  (xxxin.  416 
represents  the  creature  extended.)  1-36". 

N.  centrura  (xxxviii.  26).— Body  large, 


OF  THE  HTDATINJEA. 


685 


attenuated  at  both  ends.  Usually  sui'- 
roimded  by  a  broad  gelatinous  sheath, 
either  hyaline  or  filled  with  small  aci- 
cular  bodies.  According  to  Ehrenberg, 
in  this  sheath  vegetate  threads  of  Hy- 
drocrocis ;  but  these  could  not  be  found 
by  Leydig.  Sheath  wanting  in  young 
specimens.  Cuticle  thick,  soluble  in 
caustic  potass.  Behind  the  middle  of 
the  body,  on  each  side,  is  a  small  conical 
eminence  (xxxvni.  26  ft),  surmoimtedby 
a  bunch  of  long  setae.  Rotary  organ  pe- 
culiar, differing  from  Ehrenberg's  repre- 
sentation. Anterior  ciliated  extremity 
small  compared  vnt\\  the  size  of  the 
animal ;  ventral  portion  (fig.  26  c7)  pro- 
longed in  the  form  of  a  half  canal  or 
gTOOve,  constituting  a  kind  of  under  lip. 
At  the  base  of  this  is  the  mouth,  com- 
municating with  the  maxillary  bulb  and 
oesophagus,  and  opening  into  a  stomach 
with  walls  composed  of  large  cells  (fig. 
26/),  beyond  which  is  a  restriction 
separating  it  from  the  rectimi  (fig.  20)  g). 
Three  sac-like  organs  (fig.  26  t,  c)  on  the 
hinder  border  of  the  brain  (fig.  26  k)  : 
the  centre  one  composed  of  clear  vesicles 
(fig.  26  c),  the  outer  t^^o  apparently 
sometimes  continuous  ^\dth  the  cerebral 
ganglion.  They  are  granular,  nucleated, 
and  apparent  Avith  some  inorganic  mat- 
ter, which  is  white  by  reflected  and  dark 
by  transmitted  light.  Ovary  (fig.  26  o) 
transversal ;  Perty  saw  only  winter  ova 
in  it.  (xxx^Ti.  25  exhibits'^a  small  por- 
tion of  the  ovary  in  which  an  ovum  is 
forming, — a  being  the  germinal  spot,  h  a 
clear  space  sm-roimding  it,  and  c  the 
yelk-suDstance.  xxxvni.  11.  represents 
a  small  portion  of  the  water-vascular 
c^nal  with  its  tags,  and  fig.  12  the  ter- 
mination of  a  tag  with  its  contained 
ciliuni.) 

N.  hrachyota. — Small,  slightly  attenu- 
ated towards  the  ends ;  no  tail,  auricles 
very  small ;  it  has  two  dark  spots  near 
the' eye ;  foot  forked.     1-120". 

N.  Phurotrocha. — Slender,  cylindrical, 
not  auricled :  foot  with  very  short  toes ; 


eye  obscure,  ovate,  large ;  jaw  ■v^•ith  one 
tooth.  1-144".  Berlin.  Has  the  form 
of  Pleurotrocha. 

N.  vermicidaris  (Duj.). — Vermiform, 
very  contractile  ;  of  variable  form,  \^^th 
a  kidney-shaped  red  speck  (xxxviii.  33), 
in  which  is  partly  imbedded  a  white 
transparent  globide.  1-118".  Found  in 
the  Seine. 

N.  tardigrada  (Leydig)  would  be  re- 
ferable to  the  genus  Lindia  (Duj.),  had 
not  its  author  made  the  absence  of  cilia 
from  the  head  a  generic  character.  Fi- 
gure vermiform,  rounded  in  front,  pro- 
longed behind  into  a  short  biuncinate 
foot.  Mouth  a  long  fissm-e  on  the  under 
side  of  the  head,  which  is  clothed  with 
short  and  delicate  cilia,  the  only  part  of 
the  head  so  fiuiiished.  MaxiUary  bulb 
capable  of  being  protruded.  Dental  ap- 
paratus recalling  to  mind  that  oi  Echinus. 
(Esophagus  long,  resembling  that  of  N. 
centrura.  Stomach  long,  yeUow,  with- 
out cilia  on  the  free  surfaces  of  its 
parietal  cells.  Intestine  short  and  clear, 
opening  at  the  base  of  the  foot  on  the 
abdominal  surface.  Contractile  sac  vi- 
sible, giving  off  traces  of  two  water- 
canals,  but  without  vibratile  tags.  Above 
the  maxillary  bulb  the  "  sacculus  cere- 
bralis  "  of  Ehrenberg,  white  by  reflected 
and  black  by  transmitted  light,  and 
soluble  in  liquor  potasses. 

N.  roseola  (Perty). — Body  of  a  pale 
rosy  red,  elongated,  rounded  in  front. 
Rotary  organ  forming  a  cylindrical  pro- 
cess on  each  side  of  the  head.  Cohn 
suggests  that  the  animal  may  be  identical 
with  his  Li)idia  toridosa. 

N.  onisciformis  (Perty). — Body  broad 
like  an  Oniscus,  with  a  roimd  lappet  on 
each  side  of  the  head.  Jaws  strong, 
many-toothed;  tail  flat,  rather  long. 
Entire  anterior  extremity  capable  of 
being  retracted.  An  ear-like  lappet  on 
each  side  of  the  head,  between  which 
are  seen  the  vibratile  cilia.  No  alimen- 
tary canal  seen  beyond  the  maxillary 
bulb.     Amongst  Confervae  and  Charse. 


Genus  SYNCH^TA  (XXXIII.  422).— Eye  single,  cei-^dcal ;  rotary  organ 
of  six  to  ten  lobes,  and  armed  with  from  two  to  four  styles ;  foot  fui'cate. 
The  strong  styles,  or  bristles,  are  situated  between  the  clusters  of  cilia,  and 
probably  act  as  tactile  organs  ;  the  body  is  very  short,  broad  anteriorly,  and 
tapers  to  a  point  posteriorly,  or  is  conical.  Internal  longitudinal  muscles 
exist  in  all  the  species ;  those  of  the  foot  are  seen  in  three  species  :  the  oeso- 
phageal head  is  large,  with  single -toothed  jaws  ;  but  in  two  species  only  is  the 
whole  che'wing  apparatus  distinctly  seen.  The  thin  oesophagais  is  long  in  two 
species,  short  in  the  rest;  it  leads  to  a  simple,  wide,  conical  alimentary 
canal,  which  has  two  roundish,  or,  in  one  species,  conical  pancreatic  glands. 


686 


SYSTEMATIC  HISTORY  OF  THE  IXFUSOEIA. 


The  ovary  is  rolled  up  like  a  ball ;  contractile  vesicles  exist  in  three,  and 
glands  in  two  species;  transverse  bands  (foiu'  to  ten)  are  visible  in  two 
species,  and  probably  a  respirator}^  tube  in  S.  jjectinata  and  S.  tremula,  a 
ti'emulous  gill  being  also  present  in  the  former.  The  principal  nervous  matter 
is  a  knotty  mass  suiTounding  the  head  of  the  oesophagus ;  and  in  the  middle 
of  it  is  a  large,  roundish,  red  eye.  In  S.  pectinata  three  pair  of  gangha  and 
strong  nerves  are  also  said  to  be  seen ;  but  this  is  doubtful.  Abdominal  fluid 
of  a  reddish -yellow  colour.  (For  remarks  on  the  genus,  see  Hydatina,  p.  677.) 


Synchjeta  pectinata. — Short,  conical, 
with  two  styles  and  two  crest-like  horns 
anteriorly.  "  Are  these  horns,"  asks 
Ehrenberg,  "respiratory  tubes,  as  in 
Pohjarthra,  and  in  Anur(ea  ?"  The  live- 
liness and  uniform  transparency  of  this 
animalcule  render  it  difficult  to  distin- 
guish its  various  organs.  The  styles 
arise  from  the  muscle  of  the  oesophageal 
head,  and  appear  as  if  belonging  to  simple- 
toothed  jaws.  Eye  blue.  Egg-yelk  con- 
taining heaps  of  red  fat-globides.  (xxxui. 
422,  a  dorsal  view  showing  its  organiza- 
tion.)    Amongst  Confervae.     1-120". 

S.  Baltica. — Ovate  ;  rotary  clusters 
and  styles,  four  each ;  crest  single,  sessile. 
This  creature  is  supposed  to  occasion 
phosphorescent  light  in  the  ocean.  In 
two  samples  of  water  received  by  Ehren- 
berg at  Berlin,  from  Kiel,  the  Imninous 


tion  of  light  from  this  SynchcBta,  as  did 
Baker  a  century  ago.  Ehrenberg  thinks 
it  takes  place  only  when  developing  ova. 
1-100".^  . 

S.  ohlonga. — Oblong,  with   six  rotary 
clusters,  and  four  styles ;  crest  sessile  and 


single. 


Distinguished  from  the  follow- 


ing by  the  form  of  the  pancreatic  glands. 
Amongst  Coufervae  in  spring.  Length 
about  1-100". 

S.  tremula  (  VorticeUa  tremula,  M.). — 
Body  tridy  conical,  wdth  six  rotary  clus- 
ters, four  styles ;  crest  none  ;  granules  of 
yelk  dark  coloured.  Length  about  1-160". 
Mr.  Gosse  thinks  this  may  be  a  dioecious 
species. 

S.  mordax  (Gosse).  —  Body  conical, 
subventricose;  toes  minute;  auricles  large, 
pendent  j  principal  styles  four,  the  larger 
(or  lateral)  pair  sometimes  branched ;  eye 


property  existed;  but  this  species,  though  |  rather  small,  briUiant ;  two  pahs  of  pro- 
present,  did  not  evolve  any  light.     Mi-  j  trusile  snapping  jaws.  '  1-72". 
chaelis,  however,  has  noticed  the  produc-  | 


Genus  SCARIDIUM  (XXXUI.  423).— Eye  cervical,  single,  flat,  lenticular, 
the  compound  rotary  organ  armed  in  front  with  an  uncinus  or  hooked  bristle ; 
foot  forked,  very  long,  and  adapted  for  leaping  or  sprmging — hence  the  name. 
Oesophageal  head  oblique,  with  unequal,  double -pointed  (single)  teeth  to  the 
jaws ;  oesophagus  short,  narrow,  opening  into  a  simple,  wide,  conical  alimen- 
tary canal ;  supposed  glands  spherical,  two.  Posteriorly,  above  the  intestine, 
are  a  ball-like  ovaiy  and  a  contractile  vesicle.  The  foot  has  two  club-shaped 
muscles ;  and  its  apparent  articulations  are  very  remarkable.  A  central  gan- 
glion exists  between  the  rotary  lobes.  Muscles  with  transverse  strise.  Shell 
of  the  ovum  (winter  ovum  ?)  clothed  at  both  ends  with  scattered  hairs. 


ScAniDiUM  longicaucla  (Trichoda  longi- 
cauda,  M.). — Foot  twdce  as  long  as  the 
body,  toes  half  as  long  as  the  foot ;  the 
animal  springs  or  leaps  quickly,  by  a 
rapid  movement  of  the  foot ;  it  does  not 
appear  to  have  a  lorica,  and  is  distin- 
guished from  all  other  Rotatoria  by  the 
length  and  bending-in  of  the  foot,  which, 
as  also  the  body,  is  covered  with  a  stiff 


skin.  Behind  the  eye  is  a  transverse 
fold  in  the  neck,  where  the  head  di'aws 
itself  into  the  body ;  the  foot  has  also  a 
transverse  fold  when  it  bends,  (xxxiii. 
423,  the  animalcide  extended,  right  side ; 
fig.  424  the  CESophageal  head,  with  un- 
equal jaws,  &c.,  extended  by  pressure.) 
Amongst  Oscillatorise.  Entire  length  of 
thebodv  1-72";  without  the  foot,  1-216". 


Genus  POLYARTHRA  (XXXIII.  400-402 ;  XXXVIII.  30).— Eye  single, 
cervical ;  foot  absent ;  provided  with  cirri,  or  pectoral  fins.  The  rotary  organ 
consists  of  four  bundles  of  ciha,  inserted  in  as  many  muscular  sheaths ;  they 
sometimes  appear  like  the  double  rotary  organ  of  a  Brachiomis.  The  form 
of  the  body  resembles  Annrcca ;  but  it  is  soft,  and  the  rotary  organ  double. 


OF  TnE  nYDATIN.EA. 


68: 


Laterally  there  arc  two  longitudiual  dorsal  muscles ;  the  frontal  region  has 
little  homs,  pro\ided  with  bristles  ;  and  upon  the  breast  are  six  strong  styles, 
or  barbs,  forming  two  clusters,  which  move  in  a  fin-like  manner.  The  oeso- 
phageal head  has  two  single- toothed  jaws ;  oesophagus  short ;  alimentary 
canal  with  a  stomach-hke  division,  produced  by  a  constriction ;  supposed 
pancreatic  glands,  two.  An  ovary  exists  in  both  species,  and  in  one  of  them 
a  contractile  vesicle ;  a  large  frontal  ganghon  and  a  round  red  eye  indicate 
the  system  of  sensation. 

The  preceding  genera  of  this  family,  together  with  two  peculiar  to  himself, 
yjz.  Plagiognatlia  and  Lindia,  form,  in  the  system  of  Dujardin,  the  family 
Flosculariens ;  but  the  genus  Polyarthra  and  a  few  others  in  this  family  of 
Ehrenberg  belong  to  the  Brachioniens  of  that  author. 

From  the  remarks  of  the  French  naturalist,  it  is  to  be  inferred  that  he 
regards  the  distinction  between  Polyarthra  and  Triartlira  as  insufficient. 


PoLYARTHEA  pMypterci  (xxxviii.  30, 
also  XXXIII.  400-402  &  425).  —  Ciliary 
wreath,  according  to  Perty,  not  as  de- 
scribed by  Ehreuberg  and  JDujardin,  but 
continuous  and  symmetrical,  with  two 
eminences  crowded  by  setse,  besides 
which  are  several  long  styliform  cilia. 
Near  the  posterior  end  of  the  body  are 
two  fossae  ^\\th.  unsymmetrically  arranged 
setae  extending  from  them.  Alimentary 
canal  consisting  of  a  conical  oesophageal 
bulb,  stomach,  and  intestine.  Stomach- 
cells  ciliated ;  contractile  sac  present, 
but  no  water- vascular  system  seen  ;  lon- 
gitudinal muscles  striated;  abdominal 
fluid  yellowish-red ;  ovary  somewhat  bi' 


fat-globules.  No  winter  ova  seen.  Em- 
brs'o  ^Tith  bluish  spots.  Ova  adhering  to 
the  exterior  of  the  body ;  only  one  seen 
at  a  time  (Ley dig).  It  swinis  quickly, 
and  often  leaps,  like  the  water-flea :  this 
last  motion  is  produced  by  the  fins  or 
pinnae,  the  former  by  the  vib'ratile  organs. 
(Figs.  400,  401,  &  425  represent  the  P. 
Trigla  of  authors;  but  Leydig  has  decided 
that  it  is  identical  with  P.  platyptera. 
Fig.  425  the  under  side  while  the  ani- 
malcule is  swimming,  with  the  pinnae 
depressed ;  fig.  400  a  dorsal  view  while 
leaping  or  springing ;  and  fig.  401  a  side 
view,  right.)  This  creatm-e  is  infested 
with  Colacium,  Amongst  Conferv^e. 
1-140". 


Genus  DIGLENA  (?). — Eyes  two,  frontal ;  foot  forked.  Excepting  the 
foot  and  rotary  organ,  they  have  no  external  prominent  organ,  though  some 
protrude  the  teeth  in  a  pincer-like  manner.  The  oesophageal  bulb  has  single- 
toothed  jaws  ;  the  oesophagus  is  very  short,  except  in  D.  lacustins ;  alimentary 
canal  conical,  simple,  in  six,  and  constricted  in  two  species.  In  aU,  two 
glands  are  present,  which  in  D.  lacustris  are  long  cylindrical  and  two- 
horned ;  in  the  rest  they  are  spherical.  The  ovary  in  D.  lacustris  is  band- 
hke,  in  the  others  globose.  Contractile  vesicles  are  observed  in  four  species. 
No  species  is  viviparous ;  none  carry  their  egg  hanging  to  them  ;  transverse 
muscular  bands  are  seen  in  three,  and  in  one  a  vascular  network  at  the  head ; 
tremulous  tags  are  found  in  three  species,  in  two  of  which  they  appear  as  if 
attached  to  the  water- vascular-canal  glands.  The  cerebral  ganglion  is  more 
especially  developed  in  D.  lacustris,  but  is  indicated  in  aU  the  species  by  the 
coloured  eyes. 

'  teresting  animalcide,  yvith.  a  Lynceus — 
see  Microscopic  Cahinetj  pi.  vii. — in  its 


DiGLENA  lacustris. — Stout,  oval,  cry- 
stalline ;  the  front  straightly  truncated ; 
foot  suddenly  attenuated,  in  length  one- 
fom-th  of  the  body ;  the  toes  one-third 
the  length  of  the  foot.  The  transparency 
of  this  animalcule  is  often  a  great  hin- 
drance to  the  discrimination  of  its  internal 
organs,  though  they  are  very  large  ;  the 
superficial  skin  is  delicatelv  sliagreened. 
(xxxni.  403  a  side  view,  left,  of  this  in- 


stomach ;  its  cimous  internal  organiza- 
tion is  clearly  depicted.  Often  found  in 
green-coloured  water.)    1-70". 

D.  grandis. — Long,  slender,  and  cylin- 
drical, obliquely  truncated  anteriorlv ; 
toes  straight,  longer  than  the  stout  foot. 
The  forked  central  sacculus,  near  the 
head,  is  remarkable,    (xxxiii.  404  an  ex- 


688 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


tended  animalcule^  riglit  side ;  xxxin. 
405  another,  contracted,  with  the  jaws 
pushed  out.)     1-120"  to  1-72". 

D.  forcipata  ( Vorticella  vermicularis, 
Cercaria  forcipata  et  £.  verinicularis,  M.) 
(xL.  24). — Cylindrical,  slender,  obliquely 
truncated  anteriorly ;  toes  decurved,  and 
longer  than  the  stout  foot.     1-110". 

D.  (?)  aurita  {Vorticella  Canicula,  M.). 
— Cylindrical,  slender  ;  front  straightly 
truncated,  auricled ;  foot  suddenly  con- 
stricted, toes  small.  The  tremidous  organ 
obsen'ed  by  Corti  was  merely  the  vibra- 
tile  lining  membrane  of  the  anterior  por- 
tion of  the  alimentary  canal.  Amongst 
ConfervEe.  1-160". 

D.  catellina  {Cercaria  cateUina,  Vorti- 
cella Larva,  M,). — Oblong,  short,  ends 
ti'uncated  ;  foot  short,  and  inferior.  The 
small  size  of  this  animalcule  is  unfavour- 
able for  observing  its  internal  organiza- 
tion. It  is  found  at  all  seasons  of  the 
year  in  open  water,  and  in  infusions 
covered  with  a  green  pellicle,  which  is 
often  filled  with  its  eggs;  these;  when 


rapidly  developed  by  genial  weather, 
cause  a  milky  turbidity  in  the  water 
1-360". 

D.  conura. — Ovate-oblong,  straightly 
truncated  in  front,  and  gradually  attenu- 
ated to  a  conical  foot.  Amongst  Oscilla- 
torise.  1-144". 

D.  capitata. — Oblong,  conical,  obliquely 
truncated  and  dilated  in  front ;  toes  long, 
without  apparent  base,  or  foot.  Feeds 
upon  Chlamydomonas  and  Navicula. 
1-300". 

D.  caudata  {Vorticella  fur cata,  M.). — 
Elongated,  conical,  obliquely  truncated 
anteriorly,  but  not  dilated ;  foot  distinct, 
short ;  toes  long.  In  gi-een  water.  1-200". 

D.  (?)  biraphis  (Gosse). — Oblong,  the 
head  and  abdomen  gently  swelling ;  toes 
long,  slender,  straight,  and  perfectly 
even  in  thickness ;  eyes  placed  close  to- 
gether, frontally;  jaws  protrusile;  alimen- 
tary canal  very  large,  projecting  behind 
and  above  the  gizzard,  always  filled  with 
green  matter.  Length,  including  toes, 
1-110". 


Genus  TRIAETHRA  (XXXIII.  406-408).— Eyes  two,  frontal;  foot 
simple,  styliform ;  breast-fins  two.  Beside  the  rotary  organ,  internal  band- 
like  muscles  are  observed,  and  two  bristles,  or  fins,  which  assist  in  leaping, 
as  in  Polyartlira.  The  oesophageal  bulb  has  two  double-toothed  jaws,  as  in 
Rotifer ;  the  oesophagus  is  long  in  one  species,  short  in  the  other ;  alimentary 
canal  simple,  conical  or  constricted,  with  two  spherical  glands.  An  ovary 
and  contractile  vesicles  are  seen ;  the  eggs,  when  expelled,  remain  attached 
by  threads.  The  nervous  system  is  indicated  by  the  two  red  eyes,  placed 
upon  ganglia.  Both  species  often  produce  a  milky,  tiu-bid  appearance  in  the 
water,  when  developed  in  masses.     A  thii'd  species  is  now  added. 

when  the  animal  is  swimming ;  406  a  side 
(right)  view  of  a  full-grown  specimen — 
the  styles  are  advanced,  preparatory  to 
leaping.)  Found  with  Hydatina  senta 
and  Brachionus  urceolaris.  Length,  with- 
out cirrhi,  1-140". 

T.  mystacina  {Brachionus passus,  M.). — 
Eyes  close  together ;  two  anterior  cirri, 
or  bristles ;  foot  nearly  double  the  length 
of  the  body;  jaws  very  soft.  1-216". 
In  water-tulbs. 

T.  breviseta  (Gosse).  —  Cylindrical ; 
pectoral  and  caudal  spines  each  about 
one-fifth  of  total  length,  and  very  slender. 
Length,  including  foot,  1-185".  Leaming- 
ton. 


T.  longiseta  {Trichoda,  M.).— Eyes 
distant ;  the  cini  or  beards,  and  the  foot, 
are  nearly  three  times  the  length  of  the 
body.  This  species  is  distinguished  from 
the  following  one  by  the  greater  length 
of  cim ;  by  larger  eyes,  further  removed 
from  each  other ;  by  a  distinct  stomach, 
with  a  constriction  separating  it  from 
the  long  portion  of  the  alimentary  canal ; 
and,  lastly,  by  its  long  oesophageal  tube. 
It  is  readily  distinguished  by  its  leaping 
movement  whilst  swimming,  (xxxiii. 
408,  a  young  animal  emerging  from  the 
e^^,  the  cirri  or  styles  being,  as  yet,  soft ; 
407,  back  view  of  a  young  specimen — it 
shows  the  gi'eat  separation  of  the  eyes  and 
the  styles,  in  the  position  they  occupy 

Genus  RATTULUS  (XXXIII.  409).— Eyes  two,  frontal;  foot  simple, 
styHfonn ;  no  cim  or  beard.  The  organization  at  present  discovered  com- 
prehends several  undefined  rotary  muscles,  an  oesophageal  head,  mthout  di- 
stinct teeth  or  oesophageal  tube,  a  simple  conical  alimentary  canal,  with  two 
round  glands,  an  ovary,  and  the  eyes. 


OF  THE  HYDATIX^A. 


689 


This  genus  (Battidus,  or  Ratulus)  was  established  by  Lamarck ;  but  the 
animals  included  in  it  by  him  were  referred  by  Ehrenberg  to  two  genera, 
Mastigocerca  and  Jibnoc^rca,  and  the  term  Rattulus  conferred  upon  an  animal 
placed  among  Cercariae,  and  called  by  Miiller  Tr'ichoda  Junaris.  '^  The  Mas- 
tigocerca caiinata  (Ehr.),"  observ^es  Dujardin,  "  is  described  as  loricated,  and 
enters  into  the  family  Euchlanidota ;  and  Monocerca  Rattus,  without  lorica,  is 
placed  among  the  Hydatinoea;  but  the  beings  described  under  these  two 
appellations  represent  but  a  single  species,  Ratulus  ....  The  Monocerca 
bicornis  of  Ehi^enberg  would  seem  to  be  a  distinct  species,  by  reason  of  the 
horns  with  which  it  is  armed  in  front." 


Rattulus  lunaris  (Trichoda  lunar  is, 
M.).  —  Small ;  eyes  remote  from  the 
frontal  margin ;  foot  decurved,  lunate. 
No  teeth  are  seen  (xxxiii.  group  409). 


In  turfy  pools.     1-288" 
R.   carinatus  (Duj.) 
Monocerca  Rattus. 


(xxx-^^ii.  22); 


Oenus  DISTEMMA. — Eyes  two,  cer^•ical ;  foot  forked ;  ix)tary  organ  com- 
poimd.  The  oesophageal  head  supports,  in  three  species,  jaws,  with  two  teeth 
each ;  in  one  sp*3cies  with  more  than  two ;  oesophag-us  short ;  aUmentary 
canal  simple,  conical,  with  two  spherical  glands.  An  ovary,  and  in  D.  (?) 
marinum  glands  and  a  contractile  vesicle  are  seen.  No  satisfactory  details 
of  a  water-vascular  system  are  ascertained ;  the  eyes  are  red,  except  in  one 
species,  in  which  they  are  colouiiess,  and  in  all,  except  D.  marinum,  they  are 
situated  behind  the  head  of  the  oesophagus ;  in  that  one  they  are  anterior, 
but  below  the  rotary  organ.  The  eggs  are  never  attached  to  the  parent,  nor 
are  they  developed  in  large  masses. 


DiSTEMiviA  Forjicula.  —  Cylindrico- 
conical ;  eyes  red ;  toes  thick,  recurved 
and.  dentate  at  the  base.  The  eyes  are 
placed  at  the  end  of  a  long  cylindrical 
nervous  ganglion  ;  the  rotary  organ  con- 
sists of  four  parts,  xxxiii.  411  is  a  side 
(left)  view,  and  fig.  410  shows  the  jaws 
extended  for  seizing  prey.  Perty  be- 
lieves this  to  be  identical  with  Fnrcu- 
iaria  Forjicula,  ha^^ng  but  a  single  eye. 
1-120". 

D.  setigerum.  —  Ovato-oblong  ;    eyes 


red  ;  toes  setaceous  and  decurved. 
1-216". 

D.  (?)  marinum. — Ovato-conical ;  eyes 
red,  close  together ;  foot  long ;  toes  thick, 
the  length  of  the  foot ;  jaws  many- 
toothed.     In  sea-water.     1-144". 

D.  (?)  forcipatum.  —  Ovato-oblong  ; 
eyes  colourless ;  foot  short,  with  stout 
toes.  If  the  two  colourless  vesicles  are 
not  eyes,  it  must  be  placed  in  the  genus 
Pleurotrocha.     1-288". 


Genus  TRIOPHTHALMUS  (XXXIII.  412-414).— Eyes  three,  cervical, 
sessile,  in  a  row ;  foot  forked ;  rotaiy  organ  compound.  It  has  a  large  oeso- 
phageal head,  with  two  (single-toothed  ?)  jaws,  a  long  thin  oesophagus,  a 
globose  stomach-like  protuberance,  with  two  oval  glands,  and  a  thin  intes- 
tine ;  two  muscles  move  the  foot.     Several  small  tags  seen  in  T.  dorscdis. 

Teiophthalmus  dorsalis. — Body  cry- 
stalline, turgid ;  central  eye  largest ;  foot 
suddenly  attenuated,  its  length  half  that 


of  the  body.     This  species,  in  form,  re- 
sembles Notommata  ansata,  but  in  size 


N.  Mijrmeleo,  (xxxiii.  412,  dorsal  side  of 
an  animalcule  extended  as  it  appears 
when  swimming  and  vibrating ;  fig.  413 
one  in  the  act  of  unfolding  itself,  and 
fig.  414  another  contracted.)     1-40". 


Genus  EOSPHORA  (XXXIII.  415).  — Eyes,  according  to  Ehrenberg, 
sessile,  three — two  frontal,  one  cervical ;  foot  forked.  The  rotary  organ  is 
composed  of  numerous  muscular  portions.  An  oesophageal  head,  provided 
with  two  single -toothed  jaws,  a  short  oesophagus,  a  simple  conical  alimentary 
canal,  Tvdth  two  ovate  glands  anteriorly,  an  ovary,  somewhat  extended,  and 
a  contractile  vesicle,  are  also  discoverable.     Transverse  bands  are  observable 

2y 


690 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


in  two  species,  and  tags  in  the  third.  Beside  the  three  red- coloured  ej-es,  a 
cerebral  gangUon  is  seen.  Distinctly  striated  longitudinal  muscles  are  seen 
in  all. 

According  to  Leydig,  what  Ehrenherg  has  regarded  as  two  frontal  eyes 
have  no  claim  to  the  name.  Should  this  statement  be  confirmed,  it  would 
become  necessary  to  unite  Eospliora  with  Notommata. 

EosPHOiiA  Najas.  —  Conical^  transpa- 
rent, not  am^icled  ;  toes  much  shorter 
than  the  foot,  (xxxin.  415,  an  animalcule 
fed  upon  indigo.)  Amongst  Confervse. 
1-12". 

E.  digitata. — Conical,  hyaline,  not  au- 


ricled;  toes  a  third  the  length  of  the 
foot.     Amongst  Confervse.     1-96". 

E.  elongata. — Elongated,  almost  fusi- 
form, not  auricled;  fi'ont  truncated  j  toea 
short.     1-72". 


Genus  OTOGLENA. — Eyes  three,  one  being  sessile  and  ceiTical,  the  others 
pedicled  and  frontal ;  foot  furcated.  This  large  animalcide,  the  sole  repre- 
sentative of  this  genus,  has  considerable  resemblance  to  Notommata  Myrmeho 
or  N.  clavulata.  Pour  lateral  longitudinal  muscles,  six  moving  the  rotary 
organ,  and  two  muscles  of  the  foot  are  present ;  a  toothless,  and  apparently 
jawless,  oesophageal  canal  leads  to  a  somewhat  thickened  stomach,  ending  in 
a  very  thin  intestinal  canal.  An  ovary  and  contractile  vesicles  are  observed. 
A  vascular  network  at  the  neck  represents  a  water- vascular  system.  An  oval 
cerebral  ganglion,  with  two  dark  appendages,  and  a  red  eye,  together  with 
two  little  horn-like  or  auricular  frontal  protuberances  bearing  two  visual 
points,  represent  the  nervous  system.     This  genus  has  not  been  figured. 

Otoglena  papulosa.  —  Bell-shaped,  1  with  Volvox  Glohator  and  Notommata 
turgid,  scabrous  with  papiUse.     Foimd  I  Myrmeho.     1-96". 

Genus  CYCLOGENA  (XXXIY.  425,  426).— Eyes  numerous  (more  than 
three),  conglomerate  at  the  neck  ;  foot  fiu'cate.  The  vibratile  organ  is  com- 
pound, and,  with  the  internal  muscles  of  the  foot,  serves  for  locomotion.  The 
oesophageal  head  has  two  single- toothed  (perhaps  three-toothed)  jaws ;  oeso- 
phagus very  short;  alimentary  canal  conical,  simple,  with  two  roundish 
glands.  An  ovary  and  a  contractile  vesicle  are  also  present.  Transverse 
circular  muscles,  and  six  pair  of  tremulous  organs  attached  to  the  water- 
vascular  canals,  exist.  A  purse-shaped  dark  (colourless)  body  in  the  neck, 
connected  by  a  narrow  process  to  a  large  frontal  ganglion,  containing  from 
six  to  twelve  red  points,  of  which  the  anterior  one  is  most  marked,  possibly 
indicates  a  system  of  sensation. 

Cyclogena  Lupus  {Cercaria  Lupus, 
M.).  —  Ovato-oblong,  or  conical,  not 
auricled  ;  foot  terminal,  and  short. 
(xxxiv.    425*    a   back    \'iew,    426    a 


side  view.)     1-120". 

C.  (?)  elegans. — Ovate,  not  auricled; 
foot  inferior ;  toes  long.     1-190". 


Genus  THEORrS  (XXXIY.  427-429). —Eyes  numerous  (more  than 
three),  disposed  in  two  groups  at  the  neck ;  foot  furcate.  A  compound  rotary 
organ,  together  with  two  muscles  of  the  foot,  an  oesophageal  head,  with  two 
one-toothed  jaws,  a  short  oesophagus,  a  simple  conical  ahmentary  canal,  with 
two  glands,  a  ball-like  ovarium,  and  a  double  group  of  colouiless  cervical 
eyes,  are  the  details  of  the  organization  at  present  known.  The  fi'ontal 
imcinus,  or  hook,  is  perhaps  a  respiratory  tube.  Perty  doubts  if  Ehrenherg 
is  correct  in  his  interpretation  of  the  supposed  agglomeration  of  the  eyes  in 
Theorus, 

THEonrs  vernalis.  —  Toes  small ;  no  I  creature  is  active  and  v(;hement,  like  that 
frontal  uncinus.     The  movement  of  this  |  of  an  animal  of  prey,  (xxxiv.  427,  a  back 


OF  THE  HYDATIX^A. 


601 


view  of  this  animalcule  extended,  with 
six  colourless  eyes  in  each  gi-oup ;  428,  a 
specimen  with  foui'  eyes ;  429,  body  con- 
tracted, but  jaws  extended.)  Amongst 
Oscillatoriae.     1-140". 


T.  uncinatus.  —  Toes  long,  a  frontal 
uncinus,  or  hook,  present.  Six  visual 
points  have  been  seen  by  Ehrenberg. 
Amono-st  Oscillatorise.     1-240" 


The  two  next  genera  mentioned  are  from  Mr.  Gosse,  who,  however,  adduces 
the  latter  one  as  a  doubtful  member  of  the  present  family. 

Genus  ASPLAXCHNA  (Gosse,  A.  N.  H.  1850,  vol.  vi.)  (XII.  Q^,  66 ; 
XXXVI.  7-9 ;  XXXYII.  27-32).— Eotatorial  Hydatin^a  destitute  of  foot, 
intestine  and  anus,  but  possessing  eyes  (ocelli)  and  jaws  ;  sexes  disjoined. 

This  new  genus  embraces  the  Eotatorial  animal  which  Mr.  Brightwell 
introduced  to  notice  as  ''  a  supposed  new  species  of  Notommata  "  {Fauna 
Infv^oria,  Norfolk,  1849),  and  in  which  he  first  detected  the  existence 
of  male  animals  distinct  in  organization  and  character  from  the  female. 
It  was  soon  perceived  that  the  new  forms  represented  by  Mi\  Bright- 
well  could  not  belong  to  the  genus  Notommata  of  Ehrenberg;  and  the 
discovery  of  other  similar  beings  has  led  to  the  creation  of  this  genus 
Asplanclma, 

AsPLAXCHXA  Brightwellu.  —  Jaws 
(mandibles)  one-toothed ;  eye  single  ; 
stomach  oval,  longitudinal ;  vesicle  lobed, 
larger;  tremidous  corpuscles  (gills,  Ehr.) 
affixed  to  a  long  filament;  ovary  two- 
horned.  Length  about  1-24".  (xii.  65. 
66.)  Males  with  jaws,  pharjTix,  and 
stomach  absent ;  body  truncate.  Length 
about  1-40".  Found  at  Norwich,  Lea- 
mington, Hampstead  Heath,  &c. 

Mr.  BrightweU's  account  is  embraced 
in  the  following  extracts  : — 

"  It  (the  female)  is  furnished  witli  an 
ovisac,  in  which  the  young  may  be  clearly 
detected,  and  from  which  they  are  ex- 
pelled through  the  sides  of  the  animal. 
Some  of  the  yoimg  appear  to  differ  in 
fonn  from  the  others,  and  there  appear 
to  be  two  kinds  of  ova, — one,  and  that 
by  far  the  greater  nimiber,  transparent, 
and  hatched  in  the  body  of  the  parent ; 
the  other,  more  opaque,  perhaps  remain- 
ing unliatched,  or  deposited  till  vivified 
under  favourable  circumstances  in  some 
ensuing  season.  Should  this,  on  fm-ther 
investigation,  tm'n  out  to  be  the  case, 
we  shall  have,  amono-  the  Rotifera,  the 


repeatedly  seen  the  male  in  connexion 
with  the  female.  He  attaches  himself 
to  her  side  by  his  spenn-tube,  and  re- 
mains attached  from  twenty  to  seventy 
seconds." 

For  a  more  complete  description  of 
these  very  interesting  forms  we  may 
refer  the  reader  to  the  elaborate  details 
and  figures  of  their  organization,  by  Mr. 
Dalrymple,  in  the  Pliilosophical  frans- 
actions  for  1849,  and  to  Part  I.  p.  453 
et  seq.  of  this  volume. 

Notommata  Anglica  of  Leydig  appears 
to  be  only  Mr.  Gosse's  Asplanchna  Bright- 
icelUi. 

A.  priodonta  (Gosse). — Females :  Jaws 
serrated  ;  eyes  three  ;  stomach  hemi- 
spherical, transverse ;  vesicle  spherical, 
smaller ;  tremulous  bodies  attached  to  a 
twisted  and  plicate  filament ;  ovary  sub- 
globose  (xxxvi.  9 ;  xxxviii.  28).  Leng-th 
about  1-48".  Males :  Body  acute  (xxxvi. 
7,  8).  1-110".  Found  in  the  Seroentine 
river.  (Figs.  10,  11  exhibit  the  jaws  of 
the  female  detaclied.) 

A.  SieboIdn(Nofommafa  Sieboldii,  Ley- 
dig)  (xxxvn.  27-^2). — Females  closely 
resemble  those  of  Leydig's  N.  Anglica^ 
but  the  males  differ  widely.  Female 
campanulate,  no  foot  ;  anterior  exti'e- 
mitv    widened  ;    ciliarv   ^vreath    inter- 


same  mode  of  preser^-ing  the  ova  during 
the  winter  as  is  found  in  some  of  the 
Entomostraca,  the  Daphnice  for  instance." 

''  These  [the  males]  are  smaller  than  ,  ^ 
the  females,  and  have  a  pp-iform  sac  ■  rupted  by  a  fissure  at  the  mouth,  into 
below,  from  which  there  is  an  opening,  |  which  the  fine  cilia  descend ;  two  large 
and  which  is  filled  with  spermatozoa ;  j  lobes  (32  g)  on  the  rotary  organ,  crowded 
and  they  have  neither  jaws,  nor  gullet,  \  by  setse,  wdth  two  similar  smaller  ones ; 


nor  stomach ;  and  it  would  seem  they 
are  designed,  as  is  the  case  with  the 
males  of  some  insects,  to  continue  the 
race  and  then  to  perish ....  I  have  lately 


between  these,  on  each  side,  is  a  fossa 
with  long  motionless  setae.  Mouth  open- 
ing into  an  angular  maxillary  bulb. 
Jaws  (xxxYii.  31)  with  one  furcate  piece 
2t2 


692 


SYSTE:HATIC  history  of  the  rNTUSORIA. 


hooked  at  the  end ;  on  the  inside  is  an 
aculeate  process  and  a  ridge  to  which 
strong  striated  muscles,  working  the 
jaws,  are  attached.  (Esophagus  long, 
its  lower  end  highly  musciilar ;  two 
spherical  glands  open  into  the  round 
yellowish-brown  stomach  (32  b) ;  intes- 
tine absent.  Walls  of  the  contractile 
vesicle  (32  e),  which  open  into  the 
cloaca,  with  a  muscular  network.  Two 
water-vascular  canals  on  each  side,  one 
with  granular  walls,  the  other  wider  and 
with  about  fifty  tags  (31  &  32).  Cere- 
bral ganglion  laid  across  the  maxillary 
bulb,  with  a  dark-red  or  black  speck 
above  and  behind  it  in  the  median 
line.  Cells  of  the  ganglion,  according 
to  Leydig,  fusiform,  and  prolonged  into 
nervous  cords.  A  nerve  is  said  to  pro- 
ceed from  each  side  to  the  setigerous 
fossa  of  the  rotary  organ,  where  it  swells 
out  like  a  ganglion ;  another  nerve,  from 
its  posterior  surface,  divides  to  supply  the 
smaller  eminences  on  the  rotary  organ ; 
and  another  pair  from  the  same  sur- 
face supply  the  smaller  eminences :  but 
we  think  these  supposed  neiwes  require 
re-examination.  Ovaiy  horseshoe-shaped 
(32  c).  Male  and  female  young  never  si- 
multaneously generated  within  the  same 


parent.  Winter  eggs  (xxx"^t:i.  27,  28) 
spherical,  usually  one  or  two,  never  more 
than  three ;  yelk  yellowish-red,  invested 
by  a  thin  membrane,  which  in  turn  is 
surrounded  by  a  thick  granular  tuber« 
culated  shell,  the  latter  rendered  pale 
by  potash,  which  partly  obliterates  the 
tubercles.  On  keeping  specimens  in  pure 
water  without  nomishment,  all  the  ego-s 
deposited  were  winter  ova.  Males  differ 
in  figure  (iig.  29)  from  females :  clavate, 
with  four  conical  arms ;  the  two  anterior 
ones  (29  a)  the  smallest.  When  swim- 
ming, which  it  does  on  its  back,  these 
arms  are  shortened.  Rotary,  muscular, 
and  nerv'ous  structures  as  in  the  females^ 
Pyriform  testicle  (29  c)  next  the  con- 
tractile sac,  filled  with  spermatozoa, 
amongst  which  are  round  vesicles,  nu- 
cleated fusiform  bodies  (30  b,  c),  cun^ed, 
nucleated,  sickle-shaped  objects  (30  a), 
and  stiff,  sharply-defined  rod-like  bodies 
(30/).  Duct  on  the  abdominal  surface 
at  the  end  of  the  body,  and  surrounded 
by  what  look  like  accessory  glands. 
Alimentary  canal  absent ;  the  rudimen- 
tary digestive  organs  represented  by  an 
irregular  heap  of  cells  behind  the  pos- 
terior anus.     Yoimg  males  born  alive. 


Genus  TAPHROCAMPA  (Gosse). — Rotary  organ  wanting,  body  fusiform, 
annulose ;  tail  forked ;  gizzard  oval ;  mallei  incurved,  shorter  than  the  incus, 
which  is  also  inciu'ved. 


Taphrocampa  annulosa.  —  Occipital 
mass  opaque,  white ;  alimentary  canal 
simple,  wide,  cylindrical ;  points  of  tail 
short,  conical.     1-110". 

This  species  is  evidently  allied  to  M. 
Dujardin's  Limlia  torulosa,  but  differs 
from  it  in  the  structm'e  of  the  dental 
apparatus,  and  of  the  digestive  canal. 


It  seems  to  connect  the  genus  CTieeto- 
notus  with  the  Hydatinaean  genera  No- 
tommata  and  Furcularia;  for  it  has  the 
jaws  of  these  larviform  Rotifera,  and 
the  glandular  occipital  mass  foimd  in 
some  of  them,  with  the  form,  simple 
digestive  canal,  and  manners  of  Chceto- 
notus.     Found  at  Leamington. 


We  will  append  here  two  genera  of  the  family  Furculariens  of  Dujardin, 
which  that  natm^alist  has  created  either  to  embrace  new  species  or  to  dispose 
of  those  described  by  Ehrenberg  which  Dujardin  cannot  include  with  other 
of  his  genera.  Likewise,  before  commencing  with  the  next  family  (Euchla- 
nidota  of  Ehrenberg),  we  shaU  take  the  opportunity  to  detail  the  characters 
of  a  family  discovered  and  named  by  Dujardin,  viz.  Albertiens. 

Genus  PLAGIOGNATHA  (Duj.).— Body  oblong,  curved  and  convex  on 
one  side,  or  cornet-shaped  and  obliquely  truncate  in  front ;  terminated  pos- 
teriorly by  a  more  or  less  distinct  tail,  bearing  two  styles.  Jaws  with  parallel 
branches  turned  the  same  way,  and  recurved  towards  the  ciliated  margm  with 
a  straight  central  stem  (fulcrum),  very  long  and  enlarged  at  its  base ;  eye- 
specks  one  or  two.     We  propose  this  as  a  genus  of  Furculariens. 

Although  possessing  a  curved  figui'e,  with  a  characteristic  form  of  jaws, 
Ehrenbero-  has   distributed  them  in    his  genera   Nofommafa,  DigUna,  and 


OF  THE  EUCHLANIDOTA. 


693 


Distemnut,  according  to  the  number  and  disposition  of  their  red  points,  and 
without  consideration  of  the  characters  we  employ. 


Plagiognatha  Felis.  —  The  species 
we  reo:ard  as  the  t}^e  of  this  genus  is 
the  P.  Felis,  called  by  Miiller  Vorticella 
Felis,  but  not  answerable  to  the  Notam- 
mata  Felis  of  Ehrenberg.  Its  two  styles 
are  one-fourth  of  its  entire  length,  and 
are  curved  backwards ;  the  back  is  con- 
vex, abruptly  trimcate  behind.    1-118". 

Pl.  lacinulata  has  been  classed  by 
Ehrenberg  among  the  Notommatce.  A 
variety  of  this  species  with  two  eye- 
specks  may  be  referred  to  the  Distermna 
setigera  (Ehr.). 


One  must  also  regard  as  distinct  spe- 
cies oi Plagiognatha  the  Notommata  Tigris 
and  the  Diglena  catellina  of  Ehrenberg. 
The  Diglena  lacustris  of  the  same  author 
also  corresponds  in  form;  but  its  jaws 
are  not  suiRciently  described  to  deter- 
mine its  position ;  whilst  his  Notommata 
kyptopus,  represented  with  one-toothed 
jaws,  analogous  to  those  of  om*  Furcu- 
laria,  appears  the  same  as  a  Systolide 
known  to  us,  evidently  possessing  the 
jaws  of  a  Plagiognatha. 


Genus  LINDIA  (Duj.)  (XXXIX.  1-3).— Body  oblong,  almost  vermicular, 
articulated  by  means  of  shallow  transverse  folds,  rounded  in  front ;  protrudes, 
when  swimming,  two  smaU.  clavate  organs  (3n),  clothed  with  radiating  cilia 
at  their  extremities,  and  forming  a  retractile  rotary  organ  on  each  side. 
Jaws  (fig.  2)  composed  of  thi'ee  pincer-hke  teeth.  Eye-speck  single,  in  front 
of  a  blackish  calcareous  (?)  sac.  Two  short  conical  toes  at  the  posterior 
extremity. 


LiNDiA  tonilosa  (Duj.). — Body  red- 
dish. Length  1-6'",  Perty;  1-7"',  Du- 
jardin  ;  1-8'",  Cohn.  Cohn,  whose 
amended  characters  of  the  genus  we 
have  given  above,  thinks  that  Notom- 
mata roseola  may  be  identical  with  this 
species:  the  latter  diifers  from  Notom- 
mata tardigrada,  which  it  much  re- 
sembles, in  the  presence  of  the  club-like 


rotary  organ.  Our  author  also  contends, 
in  opposition  to  Dujardin,  that  the  ceso- 
phagus  is  ciliated.  It  is  not,  however, 
quite  certain  that  they  refer  to  the  same 
animal.  It  is  distinct  from  Notommata 
vermicidaris,  which  it  resembles.  Cohn 
thinks  the  genus  Lindia  should  be  located 
amongst  Philodinsea, 


FAMILY  OE  THE  ALBEBTIJ^A  (ALBEBTIENS). 

Body  cylindrical,  vermiform,  round  in  front,  with  an  obKque  opening,  from 
which  a  ciHated  organ  protnides  itself,  almost  larger  than  the  body ;  termi- 
nated posteriorly  by  a  short  conical  tail.  Jaws  in  the  form  of  hooks,  simple, 
or  with  one  tooth  each. 

This  family  comprises  but  one  genus,  and  one  species,  Albertia  vermicidaris 
(XXXYIII.  35,  36),  which  is  found  parasitic  in  the  intestine  of  Lumhrici 
and  snails.     1-79"  to  1-47"* 

The  ova  with  their  embryos  are  seen  in  its  interior,  in  various  stages  of 
development. 

The  ciliated  apparatus,  in  advance  of  the  mouth,  is  surrounded  by  an 
appendage  in  the  shape  of  a  spur  (calcar). 


FAMILY  YI.— EUCHLANIDOTA. 

This  family  comprehends  such  Eotatoria  as  have  a  compoimd  rotary  organ 
with  more  than  two  subdivisions,  and  whose  bodies  are  enclosed  in  a  hardened 
lorica.  The  latter  is  very  variable  in  form.  Ehrenberg  has  remarked  that  it 
sometimes  resembles  the  hard  carapaces  of  tortoises,  at  others  the  shells  of 
crabs.  In  the  former  case  the  lorica  is  open  at  the  extremities  ;  and  in  the 
latter,  Ehrenberg  supposed  it  to  be  open  inferiorly  in  Euchlanis ;  but  this  is 


694  SYSTEMATIC  HISTOEY  OF  THE  INFrSOEIA. 

denied  hj  Cohn,  whose  testimony  is  to  be  relied  upon.  The  animal  contained 
^vithin  this  loriea  presents  the  typical  features  of  the  Rotatorian  class,  just  as 
some  minute  Crustaceans  (Entomostraca),  though  enclosed  between  bivalved 
cases,  retain  the  internal  organization  of  their  more  conspicuous  and  shel- 
less  allies.  The  Euchlanidota  are  provided  with  the  various  Eotatorian 
appendages — these  exist  as  set£e,  uncini,  spurs,  or  tactile  organs ;  and  all  are 
pro\ided  with  the  characteristic  tail  or  foot  terminating  in  one  or  two  digits, 
this  organ  being  largely  employed  in  locomotion,  either  as  a  rudder  or  as  an 
anchor.  The  hardened  tegument  forming  the  loriea  is  variously  prolonged 
into  spines  and  other  appendages.  Sometimes  these  are  most  developed 
anteriorly,  at  others  posteriorly,  whilst  in  Stephanops  a  broad  expansion  of 
the  front  of  the  loriea  is  developed  into  a  curious  crystalline  hood.  The  sur- 
faces of  the  loriea  Kkewise  are  variously  sculptured  and  ornamented. 

The  eye-speck,  to  which  Ehrenberg  has  attached  such  importance  in  his 
subdivision  of  this  family,  possesses,  as  Dujardin  has  pointed  out,  less  value 
as  a  basis  of  classification  than  the  Prussian  observer  supposed ;  but  if  the 
observations  of  Ley  dig  prove  correct,  the  organ  acquires  additional  interest 
fi'om  the  discovery  of  a  refracting  body  in  the  eyes  of  EucJilanis  iinisetata  and 
Steplianops  lamelJaris.  Should  these  observations  be  confirmed,  they  will  do 
much  to  remove  all  doubt  respecting  the  visual  character  of  these  organs, — 
doubts  which  are  naturally  suggested  by  the  improbability  of  \isual  organs 
being  given  to  the  embiyo  encased  in  the  egg,  whilst  the  matm-ed,  active, 
bustling  animalcule  becomes  deprived  of  them  when  its  life  seems  to  render 
theii'  presence  most  necessary.  The  exact  nature  of  the  internal  organization 
of  most  of  the  Euchlanidota  is  yet  uncertain,  and  requires  further  study; 
but  each  form,  when  minutely  examined,  is  found  to  approximate  more  closely 
to  the  Rotatorian  type.  Thus,  whilst  all  are  provided  with  a  muscular  system, 
Cohn  has  demonstrated  that  in  Eiwlilanis  the  fibres  are  of  the  striped  or 
voluntary  type.  The  same  observer  has  also  shown  that  Enchlanis  dilatata 
is  bisexual,  the  males  resembling  those  of  Hydatina  and  Asj)IancJina  in  being 
unsupphed  with  an  aUmentary  canal.  These  are  approximations  towards  a 
general  reduction  of  the  whole  class  to  a  common  type  of  organization  of  a 
higher  character  than  was  formerly  thought  to  exist  amongst  Rotifera,  but 
at  the  same  time  very  difi'erent  to  what  was  originally  attributed  to  them  by 
Ehrenberg.  The  genus  Lepadella  developes  itself  occasionally  in  such  myiiads, 
in  stagnant  water,  as  to  give  a  whitish  turbidity  to  it. 

Ehrenberg's  arrangement  of  the  genera  is  given  at  p.  478.  Dujardin 
includes  most  of  the  genera  in  his  family  Brachioniens. 

Genus  LEPADELLA  (XXXIV.  430-433).  — Eyes  absent;  foot  furcate. 
Several  trochal  muscles  are  seen,  and  foot  ones  in  two  species.  The  jaws  of 
the  oesophageal  head  are  single-toothed  in  L.  ovalis  and  L.  emargmaia ;  in 
L.  Salpjina  triple-toothed.  The  oesophagus  is  very  short  in  all ;  the  alimen- 
tary canal  below  is  constricted,  except  in  L.  Salpina,  in  which  it  is  simple. 
The  ovary  is  globular  in  all;  in  L.  Scdpina  probably  a  cerebral  ganghon  (no 
eye)  exists.     L.  ovcdis  is  sometimes  developed  in  mpiads  in  stagnant  water. 

Dujardin  has  the  following  criticisms  on  the  genus  Lepadella  : — "  Wishing 
to  derive  his  generic  characters  too  exclusively  from  the  eye-specks,  Ehren- 
berg has  separated  all  those  having  such  specks  into  several  genera  ;  consti- 
tuting of  those  with  two  eye-points  the  genera  Stephanops  and  Metopidut, 
and  of  those  with  four  red  specks  the  genus  Squamella.  But  we  are  con- 
i-inced  that  these  red  points  may  be  present  or  absent  in  the  same  species  at 
different  periods  of  development.  We  believe,  for  instance,  that  the  Lepadella 
oralis  and  Stephanops  muticus  (Ehr.)  are  but  a  single  species  ;   Lepadella 


OF  THE  EUCHXANLDOTA. 


695 


Patella  -vvdth  or  without  red  dots ;  so  also  the  Metopidia  Lepadella  and  Sqiia- 
mella  bractea  are  the  same,  and  what  we  name  Lepadella  rotundata.  More- 
over the  Squamella  ohlonga  and  Metopidia  acuminata  are  two  distinct  species 
of  Lepadella.''^ 


Lepadella  ovalis  (BracJdonus  oralis, 
M.). — Lorica  depressed,  oval,  not  emar- 
ginate,  attenuated  anteriorly,  the  ends 
truncated.  The  alimentary  canal  of  this 
animalcule  is  generally  filled  with  a  yel- 
lowish substance,  except  when  it  feeds 
upon  colomiess  Monads,  (xxxiv.  430,  a 
back  view;  431,  a  side  (right)  view  of  a 
young  specimen ;  432,  the  lorica 
oesophageal  head.)    1-240". 


433,  the 


L.  emarginata  (Brachionus  Spatella  et 
ovalis,  M.).  —  Lorica  depressed,  oval, 
broad  anteriorly,  extremities  emargi- 
nate.  Amongst  Confeiwse.  Length, 
without  foot,  1-576". 

L.  (?)  Salpina.  —  Lorica  oblong,  pris- 
matic, obtusely  triangular,  back  crested, 
denticulated.  Amongst  Confervse.  Length 
of  lorica  1-200". 


Genus  DIPLAX  (Gosse). — Eesembles  Salpina ;  but  the  eye  is  wanting, 
and  the  lorica  (which,  as  in  that  genus,  is  cleft  doTVTi  the  back)  is  destitute 
of  spines  both  in  front  and  rear ;  foot  and  toes  long  and  slender.  It  forms  a 
connecting  link  between  Salpina  and  Dinocliaris.  The  name,  signifying 
double,  alludes  to  the  gaping  lorica,  which  forms  two  parallel  plates. 

In  accordance  with  the  tabular  disposition  of  the  family,  this  genus  follows 
next  after  Lepadella. 


DiPLAX  compressa.  —  Form  of  lorica 
(viewed  laterally)  nearly  a  parallelo- 
gi'am,  greatly  compressed.  Lorica  1-176". 

D.  trigona. — Lorica  three-sided,  a  sec- 


tion forming  a  nearly  equilateral  triangle, 
sm^face  delicately  punctm-ed  or  stippled  j 
toes  long  and  slender.  Lorica  1-160". 
Leaming-ton. 


Genus  MOjN^OSTYLA  (XXXIY.  434-437).  — Eye  single,  cervical;  foot 
simple,  styliform ;  lorica  (testula)  depressed,  ovate.  Numerous  muscles  have 
been  noted  in  two  species — the  oesophageal  head  has  four  muscles ;  in  one 
species  the  jaws  are  single-toothed,  in  the  other  two-toothed.  QEsophagus 
very  short ;  stomach  constricted  (Gasterodela),  with  two  glands.  The  ovary 
is  globular ;  an  ovum,  with  the  vesicle  of  the  germ  within  it,  was  seen  in  two 
species.  No  male  organs,  vessels,  or  respiratory  tubes,  are  seen.  Owing  to 
the  almost  constant  vibration  of  the  foot-like  tail,  it  is  difficult  to  observe  the 
true  form  of  its  termination,  the  motion  producing  an  optical  deception; 
hence  it  appears  double,  though  in  reality  it  is  single. 


MoNOSTYLA  cornuta  (Trichoda  cor- 
nuta,  M.).  —  Lorica  hyaline,  unarmed, 
and  trimcated  anteriorly.  Amongst 
Charae  and  Confervse.     1-250". 

M,  quadridentata.  —  Lorica  yellowish, 
anteriorly  deeply  dentated,  resembling 
four  horns.  It  is  generally  of  a  yellow 
leather  colour,  but  Ehrenberg  has  seen 
it  colom-less.  (xxxiv.  434  &  435,  ventral 
aspect;  in  the  latter  the  animal  is  ex- 
tended beyond  its  lorica,  which  happens 
when  the  rotary  cilia  are  in  motion. 
Fig.  436,  a  side  view;  437,  the  jaws 
and  teeth  separated.)  In  floccose  matter 


about  Confervse  and  the  leaves  of  water- 
plants.     1-120". 

M.  (?)  lunai'is. — Lorica  hyaline,  flex- 
ible, admitting  the  retraction  of  the 
head,  anteriorly  crescent-shaped.  1-144". 
Colour  grey,  usually  so  dark  that  no 
internal  organs  are  distinguishable.  Eyes 
red  ;  jaws  large,  two-toothed ;  eggs  few. 

M.  Bidla  (6osse).  —  Body  ovate,  in- 
flated, the  back  very  gibbous ;  lorica 
plicated  on  each  side,  with  a  deep  fur- 
row ;  the  occipital  and  mental  deeply 
incised.  Colour  yellowish-brown.  Length 
of  lorica  1-175". 


Genus  MASTIGOCEECA  (XXXIV.  438-440).— Dujardin  and  Perty  be- 
lieve this  to  be  identical  with  Monocerca. 

Genus  EUCHLANIS  (XXXIY. 441-446 ;  XXXYIII.  5,18 ;  XXXIX.  4, 5, 

7). — Lorica  resembling  a  tortoise-sheU  ;  according  to  Cohn  not  slit  inferiorly, 


69(3 


SYSTEMATIC  HISTOEY  OF  THE  i:?fFrSOIlIA, 


as  described  by  Ehrenberg.  Dorsal  and  ventral  plates  united  along  the  sides, 
forming  an  acute  ridge,  leaving  a  fissnre,  posteriorly,  for  the  foot.  Dorsal  plate 
the  largest.  Frontal  portion  of  the  animal  retractile  within  the  lorica  ;  deeply 
cleft  on  its  ventral  aspect,  with  the  oral  orifice  at  the  bottom  of  the  cleft. 
Expanded  anteriorly  into  lappets  supporting  hooked  bristles.  On  either  side 
is  a  conical  process  terminated  by  a  long  stiff  seta.  Oesophagus  capacious ; 
jaws  resembling  those  of  Hydatina  and  Brachionus.  Stomach  thick  and 
rounded,  with  two  small  spherical  glands.  Intestine  pyriform,  ending  in  a 
cloaca  at  the  posterior  border  of  the  ventral  plate  ;  both  ciliated.  Contractile 
vesicle  opening  into  the  cloaca,  sending  up  on  each  side  a  coiled  water-vessel 
with  about  four  vibratile  tags.  Longitudinal  muscles  strong,  striated.  A  large 
trapezoid  cellulo-granular  organ  in  the  head,  with  a  red  speck  near  its  front 
extremity,  and  on  each  side  a  long,  finely  granular  saccular  appendage.  Tail 
with  three  telescope  segments,  ending  in  two  long  knife-hke  toes. 

Dujardin  does  not  admit  the  genus  Mo'iwsfyla,  but  places  its  three  species 
in  the  present  one — Euchlanis. 


EuCHL-Ajsris(?)  triquetra  (xxxvin.  5  a). 
— Lorica  very  large,  trilateral,  with  a 
dorsal  crest ;  setae  on  foot,  none.  This 
species  is  very  diaphanous ;  and  "  there- 
fore," remarks  Ehrenberg,  "  I  was  never 
able  to  see  the  line  of  division  on  the 
ventral  surface  of  the  lorica.  The  rela- 
tionship of  the  fibres  of  the  lateral 
muscles  is  physiologically  and  anatomi- 
cally interesting :  they  form  three  bun- 
dles, on  each  side,  and  show  as  distinct 
corrugations  as  do  the  muscles  of  larger 
animals."  (xxxiv.  443,  a  fore-shortened 
xiQ-w ;  442,  a  left  side  view,  shoTvdng 
the  dorsal  crest  of  the  lorica :  at  the 
base  of  the  foot  an  external  empty  fold 
of  the  skin  is  visible.  Fig.  441,  the  ven- 
tral surface,  showing  an  opening  for  the 
foot,  but  no  division  of  the  lorica ; 
444,  the  teeth  and  jaws  separated.)  In 
turf-pools.  Length  1-48" ;  ovum  1-192". 
(xxxviii.  5.) 

E.  (?)  Hornemanni.  —  Lorica  thin, 
short,  cup-shaped,  truncate  in  front,  the 
anterior  part  of  the  body  soft  (pliant) 
and  elongated.  This  creature  appears 
able  to  draw  within  the  lorica  both 
foot  and  head.  Sometimes  longitudinal 
muscles  are  apparent.    1-432"  to  1-240". 

E.  Luna  (Cercaria  Luna,  M.). — Lorica 
cup-shaped,  the  front  excised  in  a  lunate 
manner,  toes  with  claws.  The  single- 
toothed  jaw,  the  constriction  of  the  ali- 
mentary canal,  and  the  claws  distinguish 
it  from  the  other  species.  Amongst 
CeratopIujIIum  and  Confervae.  1-144". 
According  to  Perty,  specimens  occur  of 
a  rosy  red  colour. 

'E.' 7nacrura. — Lorica  large,  ovate,  de- 
pressed ;  bristles  at  the  base  of  the  foot ; 
toes  long,  styliform.  This  species  is  di- 
etinauished  from  the  foUowmg  one  by 
its  stronger  and  longer  toes.     "  Lately," 


says  Ehrenberg,  "  I  saw  the  division  of 
the  lorica  along  the  ventral  sm*face." 
Each  jaw  has  five  teeth ;  and  there  are 
two  soft  maxillary  appendages,  each  with 
two  teeth.  Amongst  Confen'se  in  clear 
water.  Length,  without  foot,  1-96". 
Perty  states  that  the  stomach  and  in- 
testines are  sometimes  red. 

E.  dilatata  {Brachionus,  M.). — Lorica 
broad,  depressed,  folded  on  the  mider 
side ;  foot  without  setae :  toes  long. 
This  animalcule,  when  it  emerges  fi-om 
the  e^^,  has  a  veiy  soft  lorica,  and  re- 
sembles Notommata.  Cohn  states  that 
the  males  of  E.  dikdata  are  like  the 
female,  only  smaller  and  more  slender^ 
as  well  as  more  transparent  from  the 
absence  of  mouth,  oesophageal  bulb,  and 
intestine.  The  testis  of  the  male  occupies 
the  centre  of  the  body,  and  is  a  lancet- 
like elongated  sac  (xxxix.  5  ?i),  extend- 
ino;  from  the  cloaca  to  the  cerebral 
ganglion,  and  filled  with  rod-like  sper- 
matozoa. At  its  posterior  extremity  it 
is  in  connexion  with  a  reuiform  body 
surroimding  and  opening  into  the  penis. 
The  latter  has  a  thick  wall  and  a  ciliated 
canal  protruding  as  far  as  the  first  seg- 
ment of  the  tail  (5  p  e).  Length  of 
lorica  1-8"'  to  1-20"'  (figs.  4,  5,  7). 

E.  LynceKS.  —  Lorica  ovate,  turgid, 
deeply  fiuted ;  two  little  horns  project 
anteriorly,  (xxxiv.  445,  a  back  view ; 
and  446,  a  side  view)  ;  the  lorica  is  open 
along  the  middle  of  the  imder  side. 
Length  of  lorica  1-216". 

E.  defexa  (Gosse). — Body  semioval ; 
ventral  surface  of  the  lorica  divided  lon- 
gitudinally, and  the  edges  of  the  fissure 
bent  out  at  right  angles ;  foot  furnished 
with  two  pairs  of  bristles ;  toes  spindle- 
shaped.     Lorica  1-80". 

E.  pyrifornus. — Outline  (viewed  dor- 


OF  THE  EUCHLANIDOTA. 


697 


sally)  nearly  oval^  with  a  slight  con- 
striction in' the  middle  5  lorica  divided 
longitudinally  along  the  ventral  surface, 
the  gape  widening  anteriorly;  toes  pa- 
rallel, edged ;  eye  minute.    Lorica  1-62". 

E.  Hipposicleros. — Nearly  oval  in  out-  j 
line ;  the   ventral   side  flat ;  the  dorsal  j 
greatly   arched,    and   ridged   down   the  j 
middle ;   lorica  foi-med  of  two  distinct  i 
plates ;  the  dorsal  plate  enveloping  the  j 
back  and  half  down  the  sides ;  the  ven- 
tral separated  from  it  by  a  wide  space, 
and  hollowed  in  the  middle,  so  as  to 
present  the  figure  of  a  narrow  horseshoe, 
whose  points  are  forwards:  foot  anned 
with  one  pair  of  bristles.    Lorica  1-110". 

E.  emarginata  (Eichwald).  —  Distin- 
guished from  E.  Luna  by  a  projection  at 
the  end  of  each  tail-flap. 


E.  hicariiiata  (Perty).  —  Body  elon- 
gated. Dorsum  of  lorica  with  two 
parallel  keels,  rounded  behind.  Tail 
long,  with  two  terminal  pincers;  body 
wide  in  the  middle,  contracted  towards 
each  end.  Middle  joint  of  the  tail  very 
long  ;  toe-segment  very  short.  Eye 
blackish-red.  It  is  allied  to  E.  Weissii 
of  Eichwald,  but  distinguished  by  its 
long  figure  and  long  setae  of  tail.  1-6'". 
Perty  believes  that  this  species  connects 
Euchlanis  with  Salpina.  Leydig  regards 
it  as  a  Salpina. 

E.  unisetata  (Leydig.) — Size  of  E.  cli- 
latata.  It  has  a  single  long  bristle  located 
on  the  dorsal  surface  of  the  foot-articu- 
lation ;  and,  according  to  Leydig,  the  eye 
has  a  refracting  lens  (xxxvin.  18). 


Genus  SALPINA  (XXXIY.  447-453).— Eye  single,  cervical ;  foot  fui-cate ; 
lorica  prismatic,  with  bulging  sides,  closed  below,  and  terminated  by  spine- 
like processes  or  teeth.  "  The  lorica,"  says  Ehrenberg,  "  resembles  a  three- 
sided  little  casket,  with  arched  sides,  flat  below,  and  having,  anteriorly  and 
posteriorly,  at  the  truncated  extremities,  little  points."  The  animalcule  can 
entirely  withdraw  itself  \\ithin  the  lorica.  AU  the  species  have  an  elevated 
ridge  upon  the  back,  which  in  some  appears  to  be  double.  A  compound 
rotary  organ,  two  short  anterior  lateral,  and  two  foot  muscles  are  seen  in 
S.  mucronata.  An  oesophageal  head,  with  thi'ee-  or  four-toothed  jaws,  a 
short  oesophagus,  and  a  simple  conical  alimentary  canal  exist  in  aU  the 
species ;  in  five  the  conical  intestine  has  two  spherical  glands.  The  ovary- 
is  distinct.  A  spur  or  tube  is  observed  at  the  neck  in  three  species ;  the  red 
eye  in  connexion  with  a  cerebral  ganglion  is  always  present.  They  do  not 
increase  in  large  masses. 


Salpina  imicronata  (^Brachionus  mu- 
cronatus,  M.). — Lorica  very  minutely  sca- 
brous, anteriorly  with  four,  and  poste- 
riorly with  three  horns,  generally  straight 
and  of  equal  length.  The  lorica,  when 
the  creature  is  yomig,  is  soft  and  bent, 
but  soon  hardens,  and  produces  horns. 
The  spur,  or  tactile  tube,  in  the  neck, 
temiinates  in  a  little  bristle,  as  seen  in 
XXXIV.  450.  In  some  specimens,  Ehr- 
enberg says,  the  lorica  appears  as  if 
punctate  or  stippled.  (447,  448,  full- 
grown  specimens,  with  the  head  vdth- 
di-awTi ;  the  latter  figure  is  a  back  view, 
the  former  an  under  one  ;  449,  a  side 
view,  head  extended;  451,  an  egg  just 
deposited  on  Lemna ;  452,  an  egg  vnih. 
the  young  vibrating  ;  450,  the  young 
one  just  escaped  from  the  shell;  453, 
the  teeth  separately.)     Length  of  lorica 

S,  spinigera. — Lorica  with  four  frontal  ! 
and  three  posterior  horns ;  the  posterior  j 
dorsal  one  longest,  and  a  little  recurved,  i 


Among  Ceratophylla.  Length  of  lorica 
1-140"  (xxx\T:n.  23,  24). 

S.  ventralis.  —  Lorica  stippled,  horns 
two  in  front,  three  behind,  the  dorsal 
one  short  and  decm-ved.  According  to 
Perty,  a  faint  lens  seen  in  the  eye. 
Amongst  Confervse,  &c,     1-120". 

S.  redunca. — Lorica  smooth,  horns  two 
in  front,  three  behind ;  two  of  the  latter 
(the  under  ones)  hooked,  the  dorsal  crest 
bifid  and  gaping ;  teeth  fom*  to  each  jaw. 
Amongst  Confervse.     1-200". 

S.  hrevispina. — Lorica  milky  and  tur- 
bid, but  appearing  bright;  scabrous, 
horns  two  (small)  in  fi'ont,  and  three 
behind,  short  dorsal  crest  not  gaping ; 
respiratory  tube  unknown.  Amongst 
Ceratophylla,     1-144". 

S.  hicarinata. — Lorica  smooth,  lionis 
fom-  in  front,  three  behind,  short ;  neither 
lateral  muscles  nor  respiratory  tubes 
known.     1-216". 

S.  spinigera,  S.  ventral  is,  S.  redunca, 
and  'V.  hicarinata  are  probably  slightly 


698 


SYSTEMATIC  HISTORY  OF  THE  DfFUSOEIA. 


variable  forms   of   one    and    tlie   same 
animal. 

S.  mutica  (Party). — Lorica  toothless 
both  in  front  and  behind,  truncate  pos- 


teriorly with  obtuse  angles.  Transparent. 
Eye  red.  Tail-flaps  extend  to  the  root 
of  the  tail. 


Genus  DINOCHAEIS  (XXXIY.  454-456).  —  Eye  single,  cemeal ;  foot 
furcate  ;  lorica  closed  below,  with  a  shai^)  lateral  margin,  but  unarmed  at 
both  ends.  The  compoimd  rotary  organ  has  five  or  six  muscles,  and  in  two 
species  the  foot  two.  An  oesophageal  bulb,  with  single -toothed  jaws,  is  found, 
except  in  D.  tetractis,  which  Ehrenberg  thinks  has  four  teeth ;  oesophagus 
very  short,  alimentary  canal  constricted  ;  two  oval  glands  exist  in  D.  Pocillum 
and  D.  tetractis.  An  ovary  is  seen  in  all,  and  a  contractile  vesicle  at  the 
base  of  the  foot  in  D.  Pocillum.  Traces  of  a  water-vascular  system  are 
perhaps  to  be  seen  in  D.  PociUum,  though  even  here  it  is  doubtful,  for  the 
apparently  tremulous  organ  just  behind  the  oesophagus  may  be  only  a  tre- 
mulous condition  of  an  internal  fold  of  the  stomach.  The  only  evidences  of  a 
nervous  system  are  the  eye  and  the  long  ganglion  which  supports  it. 

DiNOCHAEis  PociUum  (TricJioda  Po- 
cillum, jNI.). — Lorica  nearly  cylindrical, 
with  a  slight  dorsal  ridge;  two  long 
spines  at  the  base  of  the  foot,  toes  three, 
(xxxrv.  454,  455  represent  this  creature 
in  different  positions ;  and  456  the  oeso- 
phageal bulb.)  Amongst  Ceratophylla, 
&c.     1-120". 


D.  tetractis. — Lorica  acute,  triangular ; 


horns  two,  at  the  base  of  the  foot ;  toes 
two.  This  species  has  longer  toes  than 
the  others ;  and  the  body  is  comparatively 
shorter.  "With  Lemnae  and  Ceratophylla, 
1-120". 

D.  pauper. — Lorica  acute,  triangular ; 
horns  two,  at  the  base  of  the  the  foot, 
scarcely  perceptible :  toes  two,  short. 
1-120". 


Genus  MONUEA  (XXXIY.  457-459;.— Eyes  two,  frontal ;  foot  simple, 
styliform.  The  lorica  is  somewhat  compressed  and  open  upon  the  ventral 
siu'face  :  anteriorly  is  a  hook-Kke  process,  which  can  be  withdi^awn.  In  one 
species,  the  vibratile  organ  has  four  to  six  muscular  bulbs;  in  both,  an 
oesophageal  bulb,  with  two-toothed  jaws,  a  very  short  oesophagus,  and  a 
simple  alimentary  canal  with  two  spherical  glands  are  observed;  an  ova- 
rium, with  a  single  large  ovum,  has  been  seen.  The  eyes  are  red,  moveable, 
and  seated  upon  nervous  masses.  The  species  are  not  only  difficult  to  di- 
stinguish from  each  other,  but  also  from  the  genus  Colurus, — the  toes  of  the 
latter  appearing  single  until  pressiu-e  is  used. 


MoNUEA  Colurus.  —  Lorica  oval,  ob- 
tuse, obliquely  truncated  posteriorly, 
eyes  near  to  each  other.  Lorica  1-280". 
Siberian  specimens  1-400". 

M.  cMcis. — Lorica  ovate,  anteriorly 
acute,    posteriorly    obliquely   trimcate ; 


eyes  distant  from  each  other;  the  ali- 
mentary canal  is  often  filled  with  green 
matter.*^  They  increase  rapidly  in  glass 
vessels,  (xxxiv.  457-459  represent  three 
■\dews  of  this  animal.)  Amongst  Con- 
fervae.     Leno-th  of  lorica  1-288". 


The  two  species  of  Monurcc  are  referred  by  Dujardin  to  Colurus,  or,  to 
adopt  his  appellation,  to  Colurella. 

Genus  COLUEUS  (XXXIV.  460-462).— They  have  two  frontal  eyes,  a 
furcate  foot,  and  a  compressed  or  cylindrical  lorica.  The  lorica  is  said  to  be 
open  upon  the  under  side  (scutelhmi)  ;  a  compound  rotary  organ  is  present  in 
all,  over  which  projects  a  retractile  frontal  hook ;  an  oesophageal  bulb  with 
two  jaws,  in  two  species  with  two  or  three  teeth  ;  the  oesophagus  very  short; 
two  species  have  a  constricted  stomach  (Gasterodela),  the  others  have  a  simple 
ahmentary  canal  (Coelogastrica),  aU  with  glands.  The  two  red  frontal  eyes 
are  delicate ;  in  C.  uncinatv.s  and  C.  bicusjndatus  they  have  escaped  obsen'a- 


OF  THE  EI7CHLANID0TA. 


699 


tion ;  all  have  peculiar  vesicles  at  the  back, 
fiireate. 


They  resemble  Monura.     Foot 


CoLUEUS  (?)  iincinatus  (Brachionus 
xuicinatus,  M.).  —  Lorica  ovate,  com- 
pressed ;  posterior  and  bi-pointed  toes, 
very  short ;  at  the  middle  of  the  back  is 
generally  a  circlet  of  vesicles,  which  at 
one  time  Ehrenberg  considered  eyes,  but 
which  he  now  regards  as  vesicles  of  oil, 
as  they  are  seen  in  all  the  species,  and 
abmidantlv  in  the  Cvclopida.  In  fresh 
and  sea  water.    1-436"  to  1-288". 

C.  (?)  hicmpidatus.  —  Lorica  ovate, 
compressed ;  the  two  points  posterior, 
sti'ong  J  toes  short.     1-288". 


j  C.  caudatus.  —  Lorica  ovate,  com- 
pressed, posterior  points  distinct ;  toes 
!  longer  than  the  foot.  The  shell  re- 
I  sembles  C.  imcinatus,  but  the  toes  are 
i  much  longer.  In  fresh  and  sea  water. 
1  Lorica  1-288". 

I  C.  deflexus. — Lorica  ovate,  compressed ; 
j  the  shell  is  more  rounded,  and  very 
I  transparent,  (xxxiv.  460-462  represent 
;  back,  under,  and  side  views  ;  the  former 
shows  the  vesicles.)  In  the  clear  water 
of  a  peaty  moor.     1-240". 


Genus  METOPIDIA  (XXXIV.  463-465).— Eyes  two,  frontal ;  foot  fur- 
cate ;  lorica  depressed  or  prismatic ;  the  frontal  portion  naked  or  uncinate, 
not  provided  with  a  hood ;  indeed  they  may  be  regarded  as  Lepadelhe  with 
two  red  frontal  eyes  ;  the  lorica,  which  is  oval  and  semiciix-ular  or  crescentic 
in  front,  appears  to  be  closed  on  the  under  side  (testuJa).  In  two  species  the 
rotary  organ  has  from  three  to  four  muscles ;  and  in  one  species  two  foot 
muscles  are  observed.  Two  species  have  a  fi'ontal  hook,  like  Colurus.  The 
oesophageal  bulb  in  one  species  has  two,  in  another  four,  but  in  the  third  no 
distinct  teeth ;  a  short  oesophagus  and  two  spherical  glands  are  present  in 
all.  Two  species  have  a  distinct  constricted  stomach  (Gasterodela).  An  ovary 
is  present ;  and  M.  triptera  has  a  contractile  vesicle.  Eye,  according  to  Leydig, 
with  a  lens. 


Metopidia  LepadeUa.  —  Lorica  de- 
pressed, nearly  flat,  broadly  ovate,  ex- 
cised in  a  lunate  manner  in  front, 
roimded  posteriorly  ;  toes  somewhat 
longer  than  foot.  This  species  resembles 
in  foi*m  LepadeUa  oralis  (xxxiv.  430- 
433)  and  Squamella  Bractea  \  but  the 
foniier  has  two-toothed  jaws  and  no 
eyes ;  the  latter,  four  eyes  and  indi- 
stinctly-toothed jaws,  (xxxiv.  463-465, 
back,  under,  and  side  \news,  the  first 
and  last  having  the  rotary  organs  ex- 
tended and  in  motion.)     1-240". 

M.  acuminata.  —  Lorica  depressed, 
nearly  flat,  oval  in  shape  ;  anteriorly 
slightly  excised,  posteriorly  pointed. 
This  species  resembles  Colurus  j  but  in 
that  genus  the  eyes  are  very  close  to- 
gether,  and   the   lorica    open    beneath. 


Amongst  Oscillatorise.     1-240". 

M.  triptera. — Lorica  oval,  triangular, 
back  crested :  a  section  would  resemble 
XXXIV.  443.  Amongst  Confeiwse.  1-200". 

M.  solida  (Gosse).  —  Much  resembles 
31.  LepadeUa,  but  is  considerably  larger ; 
lorica  circular,  brilliantly  transparent ;  a 
slight  pimctation  siurounds  the  edge, 
like  that  on  a  coin.     Lorica  1-150". 

M.  oxysterna. — Resembles  M.  triptera, 
but  the  dorsal  keel  is  much  higher  and 
thinner;  the  anterior  two-thirds  of  the 
ventral  sm-face  form  a  prominent  ridge, 
terminating  abruptly  like  the  breast- 
bone of  a  bird ;  and  the  posterior  portion 
is  hollowed  out  remarkably.  Viewed 
laterally,  the  outline  of  the  back  is  very 
gibbous  behind.     Lorica  1-175". 


Genus  STEPHAXOPS  (XXXIV.  466,  467;  XL.  8-10).— Eyes  two, 
frontal ;  foot  fiu'cate ;  lorica  depressed  or  prismatic,  the  front  expanding 
into  a  hood  or  transparent  shield.  The  lorica,  in  two  species,  has  thorn-like 
processes  posteriorly.  In  one  species  a  longitudinal  muscle  is  observed  on 
each  side  (anteriorly),  two  muscles  for  moving  the  foot,  and  from  three  to  five 
belonging  to  the  compound  rotary  organ.  The  oesophageal  bulb  has  single- 
toothed  jaws,  and  a  short  oesophagus.  In  one  species  the  alimentary  canal 
is  constricted,  in  the  others  it  is  simple ;  two  species  have  glands  ;  an  ovary 


700 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOfilA. 


exists  in  all ;  a  contractile  vesicle  in  two.     The  red  eyes  are  situated  on  each 
side,  near  the  frontal  head  in  two  species  ;  in  one  they  are  yet  unknown. 

The  hood  remains  extended,  even  when  the  creature  withdi^aws  within  its 
sheU  (XL.  8-10). 


Steph.\kops  lamellaris  {Bracldomis 
la?nelIans,'!SL). — Lorica  with  three  spines 
posteriorly.  The  rapid  movement  and 
transparency  of  this  animalcide  renders 
its  organization  difficult  to  observe.  A 
process  extends  upwards  from  the  oral 
opening-  and  diverges  into  two  filamen- 
tous appendages.  Leydig  affirms  that  the 
eye  has  a  distinct  hemispherical  lens, 
and  that  the  alimentary  canal  is  divisible 
into  maxillary  bulb,  stomach,  and  intes- 
tine. The  two  latter  ciliated.  Also  a 
contractile  vesicle  present.  (xxxI^^  466, 
467,  different  views  with  the  crystalHne 


hood  or  diadem.  This  hood  is  often 
much  larger  than  is  represented  in  Ehr- 
enberg's  figures.)  Amongst  Confervse. 
Length  of  lorica  about  1-300". 

S.  (?)  muticus  (xL.  8-10).  —  Lorica 
imarmed  posteriorly,  entire.  Two  eyes, 
red.  Head  and  tail  larger  in  proportion 
to  the  trunk  than  represented  by  Ehren- 
berg.     1-144". 

S.  ch'ratus  {Brachiomis  cirratus,  M.). 
—  Lorica  with  two  spines  posteriorly. 
This  species  has  a  contractile  vesicle. 
1-240". 


Genus  SQUAMELLA  (XXXIY.  468,  469).  —  Eyes  four,  frontal ;  foot 
furcate.  The  lorica  is  closed  (testula) ;  the  rotary  organ  consists  of  five  or 
six  muscular  bulbs.  In  one  species  the  oesophageal  bulb  has  jaws,  with  two 
or  three  teeth  each;  its  tube  in  one  is  short,  in  the  other  long  and  bent 
like  the  letter  S.  Both  have  a  bipartite  intestine  (Gasterodela),  with  small 
glands ;  also  an  ovary  and  contractile  vesicle.  The  eyes  are  disposed  in  pairs 
on  each  side  the  brow. 


SQ,VAisi:Ei.i,ABractea(JBracJnomisBrac- 
tea,  M.).  —  Lorica  depressed,  broadly 
ovate.  It  is  very  transparent ;  the  toes 
thick  and  short,  not  evident.  Length  of 
lorica  1-144". 

S.  ohlonga. — Lorica  depressed,  either 
elliptical  or  ovato-oblong,  hyaline ;  toes 


long  and  slender ;  eyes  larger  than  in 
the  foregoing  species,  (xxxn^  468,  469 
represent  back  and  side  views  of  this 
animalcule.)  In  green-colom-ed  water, 
with  ChlamydomonasPukisculus.  Length 
of  lorica  1-280". 


Genus  NOTOGOx^IA  (Perty). — Body  covered  by  a  lorica  which  dilates 
posteriorly;  posterior  margin  occupied  by  two  pointed  i^rocesses  on  each 
side,  the  shorter  one  being  dii^ected  backwards  and  the  larger  one  outwards. 
Two  eyes  -widely  separated,  on  the  outer  margins  of  the  anterior  extremity. 
Jaws  curved,  strong,  with  two  or  three  teeth.  Caudal  setae  strong  and 
bristle-like. 

NoTOGONiA    Ehrenhergii.  —  Slightly    tail,  1-14'".     Motions  rather  brisk,  re- 
ventricose,  grey.      Rotary  organ  com-    sembling  those  of  Brachiomis,   Amongst 
posed  of  a  single  row  of  cilia;  eyes  very    Confervas, 
small,  pale  red.     Length,  including  the 


FAMILY  YIL— PHILODIN^A. 

This  family  comprehends  Rotatoria  devoid  of  lorica,  but  possessing  two 
simple  rotary  organs,  resembling  wheels.  The  body  of  most  species  is  worm- 
like, or  spindle-shaped  (fusiform).  Portions  of  the  body  can  be  thrust  in 
and  out,  like  the  tubes  of  a  telescope  ;  this  is  effected  by  a  sort  of  false  jorat, 
caused  by  a  peculiar  insertion  of  the  muscles.  In  aU  the  species  the  foot  is 
furcate;  and  in  CaUidina,  Rotifer,  Actinurus,  and  PhUodhia  it  is  provided 
with  soft  processes,  near  the  false  joints,  resembling  horns  in  shape,  as  in 
the  genus  Dinocharis  (fig.  455).     Muscles  are  seen  in  the  genera  just  named. 


OF  THE  PFILODIXiEA.  701 

The  nutritive  apparatus  consists  of  an  oesophageal  bulb,  with  two  jaws  ;  in 
three  of  Ehi'enberg's  genera  these  are  double-toothed  (Zygogomphia)  ;  in  two 
the  teeth  are  in  rows  (Lochogomphia),  In  the  four  principal  genera  the  ali- 
mentary canal  is  filiform  ;  it  is  furnished  -^dth  a  bladder-like  expansion  at  its 
commencement  (Trachelocystea),  and  surrounded  by  a  turbid  cellular  or  glan- 
dular mass.  In  one  genus  the  alimentary  canal  is  conical  (Coelogastrica),  in 
the  two  African  genera  its  character  is  unknown.  In  four  genera  the  intes- 
tine has  glands  ;  in  a  like  number  an  ovary  and  glands  are  present ;  a  con- 
tractile vesicle  exists  only  in  Rotifer  and  Philodina,  which,  together  with 
Actinurus,  are  also  sometimes  vi\iparous.  In  Rotifer  and  Philodina,  portions 
of  a  muscular  system  are  visible,  in  the  form  of  from  nine  to  twelve  trans- 
verse bands ;  the  same  genera,  as  also  Actinurus  and  Monolahis,  have  spur- 
like tactile  tubes.  In  thirteen  species  red  eyes  are  present;  and  beneath 
these  organs,  only  what  is  supposed  to  be  nervous  matter  is  apparent. 

For  Ehrenberg's  arrangement  of  the  genera,  see  General  History,  p.  479. 

"  The  characters  employed,"  says  Dujardin,  "  by  M.  Ehrenberg,  for  the 
distinction  of  his  genera  of  Philodincea,  have  certainly  too  slight  a  constancy 
to  be  admitted ;  that  author  has  himself  seen  the  red  specks,  which  he  calls 
eyes,  vary  in  number  and  position  in  his  Rotifers.  As  to  the  appendages  of 
the  tail  (toes),  they  are  not  always  alike  visible,  although  actually  present, 
because  the  animal  does  not  extend  them  except  at  certain  moments ;  the 
central  terminal  appendage — that  by  which  the  Eotifers  affix  themselves  to 
solid  bodies — is  itself  of  greater  or  less  length,  but  always  present.  "We 
therefore  think  that  but  two  genera  can  be  rightly  established  :  one,  CaUidinaf 
characterized  by  the  feeble  development  of  its  ciliated  rotary  organ,  and  by 
entirely  wanting  red  specks;  the  other,  Rotifer,  with  two  or  several  red 
points  placed  more  or  less  near  the  exterior  extremity,  and,  what  is  of  more 
importance,  T\ith  very  highly  developed  rotary  organs." 

"  The  genera  Hydrias  and  Typhlina  are  foimded  on  imperfect  observations 
made  by  the  author  during  his  journey  in  Egypt ;  and  the  genus  Monolahis 
ought  to  be  placed  elsewhere." 

The  family  Philodinaea  thus  fonned  is  arranged  parallel  with  Erachionsea, 
as  though  the  absence  of  a  lorica  were  the  only  difference  between  them. 

So  far  as  Dujardin  accepts  of  the  same  species,  his  family  Eotifera  and  that 
of  Philodinaea  of  Ehrenberg  correspond. 

The  amazing  persistence  of  vitahty  in  the  Rotifer  vulgaris  gives  a  great 
interest  to  this  family,  as  also  the  occurrence  of  some  of  its  members 
within  the  cells  of  aquatic  plants.  Dr.  Morren's  observations  probably  ex- 
plain some  of  the  latter  occurrences;  but  it  is  a  question  whether  recent 
discoveries  in  vegetable  physiology  may  not  further  explain  the  existence 
of  these  animals  ^vathin  closed  vegetable  sacs.  For  instance,  the  origin  of 
some  cells  by  the  vacuolation  of  a  soft  penetrable  protoplasm  suggests  the 
possibility  that  the  Rotifera  may  deposit  their  eggs  within  the  soft,  half- 
organized  protoplasm ;  and  in  the  process  of  vacuolation  some  of  these  ova 
might  readily  find  their  way  into  the  vacuoles  about  to  be  converted  into 
cells,  the  latter  change  being  completed  before  the  embryonic  animalcule 
escaped  from  its  ovum ;  and  when  it  did  so  emerge,  the  completion  of  the 
vegetable  process  would  cause  the  animal  to  find  itself  imprisoned  within  the 
waUs  of  a  vegetable  cell. 

Genus  CALLIDIjS^'A  (XXXIY.  470-473).— Distinguished  by  possessing  a 
proboscis,  and  a  foot  furnished  with  processes  resembling  horns,  and  by  the 
absence  of  eyes.  The  vibratile  or  rotary  organ,  is  double,  not  pedicled,  and 
is  surmounted  \)j  a  thickly  ciliated  proboscis.     The  furcate  foot  has  two 


702  SYSTEMATIC  HISTORY  OF  THE  INFrSOEIA. 

elongated  toes,  foiu'  little  homs  or  processes,  and  six  points.  Muscles  for 
moving  the  foot  are  also  visible.  The  oesophageal  bulb  has  two  jaws,  with 
numerous  delicate  teeth.  The  filiform  alimentary  canal  has  a  bladder-Hke 
expansion  posteriorly,  but  is  not  provided  with  glands :  it  is  siuTounded  by  a 
granular  and  cellular  mass,  whose  function  is  unknown ;  Ehi-enberg  thinks 
it  connected  with  reproduction.  An  ovarium,  with  single  large  ova,  is  seen. 
A  little  spur-like  process  projects  from  the  neck.  No  indication  of  a  nervous 
system  is  observable. 

Callidina  elegans.  —  Spindle-shaped,  |  in  the  cesophagus.     Swims  in  rather  an 


crystalline  ;  rotary  organs,  or  wheels, 
small,  (xxxiv.  470-472 ;  473,  the  eggs.) 
In  bog- water  and  infusions  of  oak-bark. 
1-72". 

C.    rediviva  (Ehr.).  —  Fusiform,    dif- 
fusely granidar  or  else  fleshy ;  with  red, 


eel-like  manner.  C.  constricta  (Duj.),  so 
named  on  accoimt  of  the  contracted  fonu 
of  its  rotary  apparatus.  Its  jaws  pre- 
sent a  row  of  closely-set  parallel  teeth. 
1-52".  ^         ^ 

C.    hklens   (Gosse).  —  Body   spindle- 


distinct  ova,  and  strong  rotary  organs.  I  shaped,  jaws  fmiiished  with  two  distinct 
1-60"  to  1-48";  ova  1-576".  Berlin;  in  !  teeth.  1-45".  Perhaps  this  is  no  other 
the  sediment  of  water-spouts  of  houses,  than  C.  elegans,  the  jaws  of  which  Ehr- 
C.  co?'nuta. — On  each  side  of  the  head  i  enberg  describes  as  having  many  delicate 


a  short  horn-like  process.  Maxillary 
bulb  much  wider  behind  than  in  C.  ele- 
gans.    Ciliary  motion  unusually  strong 


teeth.  I  have,  however,  examined  nu- 
merous specimens,  and  have  always  foimd 
them  distinctly  two-toothed. 


Genus  HYDRIAS  (XXXY.  474).— It  is  devoid  of  eyes,  proboscis,  and  the 
little  horn-like  processes  at  the  foot ;  the  two  small  rotary  organs,  or  wheels, 
are  supported  on  pedicles  or  arms. 

An  oesophageal  head,  and  an  ovary,  with  a  large  ovum,  have  been  seen  by 
Ehrenberg.  The  form  is  like  a  naked  Pterodina.  This  genus  is  constructed 
for  an  Afi-ican  Eotatorian  imperfectly  observed. 


Hydrias  cornigera. — Ovate,  hyaline  ; 
foot  attenuated,  resembling  a  tm-cate 
tail.  XXXV.  474  represents  an  animal- 
cule  extended.     With  Oscillatoriae,   in 


standing  water  from  a  small  spring  at 
Siva,  in  the  Oasis  of  Jupiter  Amnion. 
1-190". 


Genus  TYPHLIXA  (XXXY.  475).— Like  the  last,  is  an  African  forai. 
Devoid  of  eyes,  proboscis,  and  horn-Kke  processes  at  the  base  of  the  foot ; 
but  its  little  wheels  are  sessile.  It  resembles  a  very  small  Botifer,  without 
frontal  probpscis  or  eyes. 

Typhlixa  viridis.  —  Body  oblongo-  |  near  Cairo  in  Eg}^t,  in  such  numbers  as 
conical,  small  (xxxv.  475).     Foimd  by  |  to  colour  the  water  gTeen.     1-720". 
Drs.  Hemprich  and  Ehrenberg  in  a  pool  I 

Genus  ROTIFER  (XXXY.  476-480 ;  XXXYIII.  1-3).— Body  fusiform. 
Able  to  retract  and  protrude  its  little  foot  with  its  appended  horns.  Eyes 
two,  placed  upon  the  frontal  proboscis  ;  foot  provided  with  little  horn-like 
(cornicidate)  processes,  and  two  toes  bisulcate  at  theii*  apices.  A  double 
rotary  organ,  fiu'nished  with  muscles,  is  seen  in  all  the  species ;  also  longi- 
tudinal and  foot  muscles  in  three  of  them ;  a  furcate  foot  and  hom-like  pro- 
cesses in  four  species  ;  in  R.  citrinus  the  pincer-like  portions  of  the  foot 
appear  to  be  tri-pointed  ;  in  R.  erythrwus  they  seemed  to  be  drawn  in. 
In  four  species  a  muscular  oesophageal  bulb,  with  jaws,  each  two-toothed,  is 
seen ;  in  three  species  the  alimentaiy  canal  is  filiform,  ^vith  a  vesicular 
expansion  at  the  extremity,  but  no  oesophageal  tube ;  it  is  moreover  sur- 
rounded by  a  cellular  glandulose  turbid  mass  ;  another  species  has  a  conical, 
tubular  ahraentary  canal,  without  the  surroimding  mass  or  expansion  at  the 


OF  THE  PHILODIX^A. 


703 


end ;  the  four  European  species  have  two  spherical  alimentaiy  glands,  and 
an  ovary,  with  a  few  large  ova ;  occasionally  these  species  are  \'iviparous. 
In  three  of  them  a  contractile  vesicle  is  present.  In  R.  macrurus,  near  the 
alimentary  canal  are  two  glands.  In  three  species  from  nine  to  twelve 
parallel  transverse  muscular  bands  have  been  observed ;  and  besides  these, 
in  the  four  European  species,  styHform  tubes  emanate  fi^om  the  neck,  which 
in  one  species  are  ciliated  anteriorly.  Two  red  frontal  eyes  are  met  with  in 
the  four  European  forms,  and  beneath  them,  in  R.  vulgaris,  two  ganglia. 

creature  attach  itself  by  the  foot,  and 
the  rotary  apparatus  be  in  motion,  a 
strong  cmTent  or  vortex  is  produced  on 
each  side  the  wheels,  resembling  two 
spirals  in  the  water,  which  bring  the 
nutritive  particles  to  the  mouth,  from 
which  some  are  chosen  and  the  rest  flow 
away.  In  order  to  observe  this  action  with 
effect,  finely- divided  carmine  or  indigo 
must  be  mixed  in  the  water.  The  oral 
apertm-e  is  placed  just  beneath  the  hook- 
like proboscis,  from  whence  it  continues 
backwards  as  a  long  extensible  tube,  as 
far  as  the  cesophageal  head,  which  has 
four  muscles  and  two  striated  jaws  with 
double  teeth  (Zygogomphia).  From  this 
point  a  filiform  intestinal  canal  extends 
posteriorly,  forming  an  oval  expansion 
near  its  termination  at  the  anus,  at  the 
base  of  the  tail-like  foot.  A  thick  glan- 
dular cellidar  mass,  often  yeUo^\dsh  or 
greenish,  smTounds  the  alimentary  canal; 
its  use  is  unknown :  anteriorly  are  two 
biliary  glands.  The  propagative  system 
is  very  mteresting :  the  ovary  is  a  glo- 
bose glandular  mass ;  in  it  four  or  five 
ova  sometimes  so  completely  develope 
themselves  that  the  yoimg  creep  out  of 
their  envelopes,  extend  themselves,  and 
put  their  wheels  in  motion  while  within 
the  ovary ;  they  sometimes  occupy  two- 
thirds  the  length  of  the  parent.  In  the 
ovimi  the  3"0img  are  coiled  up  in  a  spiral 
manner.  A  contractile  vesicle  exists,  and 
eleven  or  twelve  parallel  transverse  bands, 
probably  muscular.  The  two  red  frontal 
eyes,  with  a  ganglion  beneath  them,  in- 
dicate a  neiTous  system.  These  eyes  are 
cells  fiUed  with  a  granular  pigment,  and 
sometimes  separate  abnormally  into  se- 
veral ;  Leydig  affirms  that  they  contain 
a  refracting  body.  (xxxv.  476,  a  fidl- 
grown  animal  extended,  and  supposed 
to  be  attached  to  a  fixed  body — the 
currents  about  the  trochal  disc  as  dis- 
played when  indigo  is  put  in  the  water ; 
477,  an  imder  view,  the  wheels  with- 
appear  to  be  present.  It  has  two  kinds  of  |  drawn,  and  body  contracted  ;  478,  an 
locomotion, — one  by  alternately  attach-  !  extended  Rotifer,  wheels  withdrawn  ; 
ing  the  mouth  and  foot,  and,  as  it  were,  479,  480,  upper  portions  more  highly 
stepping  along ;  the  other  by  swimming,  I  mag-nified,  after  submission  to  different 
through  the  rotary  apparatus.      If  the  i  degi-ees  of  pressiu'e  between  the  plates 


Rotifer  vulgaris  (  VorticcUa  rotatoria, 
M.)  (xxxv.  476-480).  — Body  fusiform, 
white,  gradually  attenuated  towards  the 
foot;  eyes  round.  This  creature,  which 
was  discovered  by  Leeuwenhoek,  was 
described  and  illustrated  in  the  Micro- 
scopic Cabinet  some  years  ago,  prior  ,to 
the  appearance  of  Ehrenberg's  observa- 
tions. "  It  has  the  power  of  contracting 
or  extending  the  length  of  the  body  in 
the  following  remarkable  manner :  — 
When  the  creature  is  about  to  shorten 
itself,  transverse  folds  or  joints  are  ob- 
servable, which  do  not  appear  to  be  con- 
fined in  number  or  situation ;  the  in- 
teguments, when  a  joint  is  produced, 
are  dra^^^l  within  the  parts  above,  and 
slide  out  like  the  tubes  of  a  telescope, 
when  the  joints  disappear.  It  is  this 
power  that  enables  it  to  assume  the 
fomi  of  a  sphere,  the  head  and  tail  being 
drawn  within  the  body."  Anteriorly  it 
has  a  proboscis-lilie  process,  with  a  cili- 
ated extremity,  and  a  soft  hook,  near 
which  are  two  dark  red  poiuts.  The  body 
terminates  posteriorly  in  a  moderately 
long  tail-like  foot,  having  six  processes 
disposed  in  pairs;  two  wreaths  of  cilia  (the 
wheels),  voluntarily  moveable,  are  placed 
upon  short  thick  arms  (pedicled),  which 
can  be  drawn  in  and  out  at  pleasure  ; 
these  MTeaths  serve  for  s-^dimning  and 
purveying,  the  food  approaching  the 
mouth  through  the  cmTents  produced  in 
the  water  by  the  cilia.  On  the  dorsal 
surface  is  a  stj^ifonn  horn  (speculum 
collar e,  M.),  at  the  end  of  which  Leydig 
detected  retractile  cilia.  During  vibra- 
tion the  neck  has  a  circular  fold,  which 
appears  on  each  margin  in  a  front  view 
like  a  lateral  style.  Four  longitudinal 
muscles,  two  anterior  and  two  posterior, 
are  seen ;  laterally  also  two,  club-shaped, 
for  moving  the  foot,  and  two  belonging 
to  the  rotary  organ.  Sometimes,  says 
Ehrenberg,  fom-  anterior  longitudinal 
muscles  and  a  dorsal  and  ventral  muscle 


704 


SYSTEMATIC  HISTOET  OF  THE  INFFSOEIA. 


of  a  compressor.  In  xxxv.  476-478,  ova 
are  seen ;  some  are  developed,  and  their 
eyes  and  oesophageal  bulb  visible.  The 
ti-ansverse  muscles,  and  the  tube  pro- 
jecting from  the  neck,  are  seen  in  the 
engravings.  Found  in  fresh  and  sea- 
water,  in  infusions,  on  the  flocculent 
matters  of  water-plants,  and  even  Avithin 
the  cells  of  some,  e.  g.  of  Sphagnum  and 
Vaucheria,  &c.  (See  Part  I.  p.  466.) 
1-50"  to  1-24". 

R.  (?)  citn?uis. — Fusiform,  lower  part 
gradually  attenuated  into  a  foot ;  its 
horn-like  processes  elongated  ;  eyes 
round  and,  according  to  Leydig,  con- 
taining a  refracting  body ',  cei-vical  tube 
toothed.  The  extremities  are  transpa- 
rent, the  middle  of  the  body  of  a  citron 
colour ;  it  often  exhibits  longitudinal 
folds,  and  is  then  less  transparent. 
Amongst  Oscillatoriae.     1-24". 

R.  (?)  erythrcBus.  —  Small,  oblong, 
suddenly  attenuated  into  a  long  foot. 
1-240". 

R.  macrurus  {Vorticella  macnira,  M.). 
—  Transparent,  ovato-oblong,  suddenly 
attenuated  into  a  long  foot ;  this  is  di- 
stinguished from  Actmurus  by  its  small 
toes,  horn-like  processes,  and  suddenly- 
attenuated  body.    The  style,  or  antennal 
tube,  is  ciliated  in  a  star-like  manner. 
The   wheels    are    prominent.      A   long  | 
stomach  is  succeeded  by  a  short  intes-  j 
tine ;  on  each  side  is  a  convoluted  water-  1 
vascular    canal,    but   without  vibratile  j 
tags.     Eyes  either  two,  hemispherical, 
abruptly '  truncate    anteriorly,   red,   and 
with  a  refracting  medium,  or  elongated 
posteriorly,  becoming  divided  into  seve- 


ral rows  of  linear  points,  without  re- 
fracting media.  It  is  altogether  a  choice 
subject  for  the  microscope.  In  boggy 
water.     1-350". 

R.  tardus. — Hyaline,  fusiform,  gi'a- 
dually  attenuated  to  the  foot,  and  having 
deep  strictures  in  the  form  of  square 
false  articulations  or  joints ;  eyes  ob- 
long. It  resembles  internally  R.  vulgaris. 
1-80". 

Of  the  several  species  of  Rotifer,  and 
of  the  following  one  of  Actinurus,  de- 
scribed by  Ehrenberg,  M.  Dujardin  con- 
fesses his  inability  to  discover  the  specific 
differences,  although  he  admits  diversity 
of  habitat,  and  of  resistance  to  the  pro- 
cess of  desiccation.  He,  however,  be- 
lieves he  has  discovered  a  Rotifer  spe- 
cifically distinct  from  any  variety  of 
Rotifer  vulgaris  ;  this  he  would  desig- 
nate 

R.  injlatus  (xxxviii.  1-3). — It  is  less 
slender  than  R.  vulgaris,  its  rotary  organs 
of  less  size,  and  its  red  specks  seated 
ver}^  near  the  jaws.  1-58".  In  water 
or  wet  moss. 

Of  this  species  Dujardin  infers  that 
Ehrenberg  has  constructed  at  least  four 
others,  accordmg  to  the  rose  oi  yellow 
colour  it  presents,  the  form  of  the  eyes, 
and  the  length  of  the  caudal  appendages, 
viz.  Philodina  eryophthalma,  P.  7'oseola, 
P.  citrina,  P.  macrostyla.  At  the  same 
time  he  would  regard  P.  coUaris,  P.  me- 
galotrocha,  and  P.  aculeata  as  distinct 
forms  of  Rotifer  a. 

R.  macroceros  (Gosse). — Wheels  large; 
antennal  process  (the  respiratory  tube, 
Ehr.)  very  long  and  mobile.     1-100". 


Genus  ACTINURUS  (XXXY.  481-484).— Eyes  two,  frontal ;  foot  fiu-- 
nished  with  two  little  horn-like  processes,  and  tliree  toes.  In  other  respects 
the  organization  resembles  Rotifer  vulgaris. 

Actinurus  Neptunius  (  Vorticella  ro-  the  case  when  crawling- ;  the  antenna  is 
tatoria,  M.). — White,  fusifonn,  gradually 
attenuated  into  a  long  foot,  having  three 
equal  toes  exceeding  the  horn-like  pro- 
cesses in  length.  The  action  of  the  jaws 
in  the  oesophageal  head  is  often  distinctly 
seen.  (xxxv.  481,  an  animal  extended, 
wdth  the  wheels  withdrawn,  which  is 


the  case  when  crawling  ; 
then  seen,  terminated  by  a  single  delicate 
hair-like  point  ;  482,  contracted,  head 
partially  withdrawn ;  484,  the  upper  part, 
when  the  wheels  are  extended  and  in 
action  ;  483,  the  oesophagus  and  jaws, 
separated  and  extended  imder  pressm-e.) 
1-36"  to  1-18". 


Genus  MOXOLABIS  (XXXY.  485,  486).— Eyes  two,  frontal  red ;  foot 
with  two  toes,  but  no  horn-like  processes.  They  are  provided  with  muscles 
for  moving  the  double  rotary  apparatus,  two  for  moving  the  foot,  and  four 
belonging  to  the  oesophageal  bulb  and  jaws,  which  last  are  furnished  with 
double  teeth,  or  teeth  in  rows.  A  very  short  oesophageal  tube  and  a  simple 
conical  alimentary  canal  are  seen  in  both  species;  one  of  them  has  two 
spherical  glands;  an  ovarium  is  seen  in  both,  but  in  neither  have  fully- 


OF  THE  PHILODIN^A. 


705 


111  one  siDecies,  a  tactile  tube 


different  views  from  the   under   side.) 
1-120".  ^ 

M.  gracilis. — Has  a  more  slender  body 
than  the  last,  and  two  teeth  in  each  jaw, 
but  no  tube  orspui".  Length  about  1-200", 


developed  ova  or  male  organs  been  observed 
is  present. 

MoNOLABis  conica. — Stout,  provided 
with  a  tactile  tube,  or  spur,  and  three 
teeth  in  each  jaw.  Between  the  rotary 
organs  the  brow  can  project  and  resemble 
a  proboscis,     (xxxv.  485,  486  represent 

Genus  PHILODINA  (XXXY.  487-490;  XXXYIII.  4). —Eyes  two, 
cervical,  foot  with  horn-like  processes.  All  the  species  possess  two  vibratile 
or  wheel  organs  upon  the  breast,  and  five  of  them  have  a  frontal  ciliated 
proboscis.  Longitudinal  muscles  are  distinct  in  one  species,  and  two  for 
moving  the  foot  in  six.  The  oesophageal  bulb  has  foui^  muscles;  its  jaws  are 
two-toothed  in  four  species,  thi-ee-toothed  in  two  species  ;  but  in  one  species 
the  oesophageal  bulb  has  not  been  satisfactorily  seen.  The  alimentaiy  canal 
is  filiform,  vaih  a  posterior  enlargement  in  six  species ;  in  one  it  appears  to 
have  pouches  or  pockets.  The  glandular  or  cellular  mass  suiTounding  the 
fiHform  part  of  the  canal  sometimes  becomes  distinctly  coloiu-ed  when  the 
creatui^e  eats  coloured  food,  and  therefore  seems  connected  with  the  nutritive 
system,  and  is  probably  a  convolution  of  caecal  appendages.  Biliary  (?)  glands 
are  found  in  six  species.  The  ovary  developes  eggs,  which  are  usually  extruded 
before  the  young  are  hatched.  Three  species  possess  a  contractile  vesicle ;  one, 
vibratile  tags.  A  tube,  in  some  cases  ciliated,  is  always  present  at  the  neck. 
Transverse  bands  are  seen  only  in  P.  erythrophtliahna.  Eyes  are  found  in 
aU  the  species,  and  nervous  ganglia  connected  with  them  in  P.  erythroph- 
ihalma  :  sometimes  the  eyes  are  veiy  pale ;  hence  a  solitary  specimen  may  be 
mistaken  for  a  CaUidina.  XXXYIII.  14  is  a  diagram  of  the  head  of  Phih- 
dina  as  viewed  in  fi'ont,  and  fig  15  of  the  same  viewed  laterally. 

Philodina  erythroplithalma  (xxxA^n. 
4). — White  and  smooth ;  eyes  roimd 
hom-like  processes  of  the  foot  short ; 
jaws  two-toothed.  Foimd  abmidantly 
dm'ing  the  spring  and  summer  in  water- 
tubs  and  amongst  Confervse.  In  glass 
vessels  it  increases  rapidly ;  and,  if  sup- 
plied occasionally  with  two  or  three  stems 
of  hay,  the  breed  may  be  preserved  for 
years.  It  is  often  met  with  in  vegetable 
infusions  of  different  kinds.  1-120"  to 
1-48". 

P.  roseola. — Body  smooth  ;  eyes  oval, 
hom-like  processes  of  the  foot  short. 
"I  have  observed,"  says Ehrenberg,  "that 
this  animalcule,  when  kept  in  glasses, 
deposits  its  eggs  in  heaps,  and  the  parent 
remains  a  long  time  with  the  young  ones 
produced  from  them,  forming  a  sort  of 
family  or  colony,  which  cu'cumstance  we 
are  not  to  be  hindered  from  ascribing  to 
a  sense  of  company  or  family,  though  the 
pride  of  man  may  laugh  at  it."  (xxxv. 
490  represents  one  with  the  wheels  ex- 
tended.)    1-72"  to  1-48". 

P.  collaris. — Body  smooth,  hyaline,  or 
white,  eyes  round ;  a  prominent  annulus 
or  collar  sm-rounds  the  neck.  It  is 
especially  characterized  by  the  extent  of 
the  alimentary  canal;  and  caecal  appen- 


dages attached  to  it ;  so  that,  when  the 
animalcule  is  fed  upon  indigo,  it  appears 
polygastric.     1-120". 

P.  macrostyla. — White  and  smooth, 
with  oblong  eyes ;  it  has  three  teeth  in 
each  jaw ;  horn-like  processes  of  the  base 
of  the  foot  long.  Foimd  amongst  Oscil- 
latoriae.     1-70". 

P.  citrina. — Smooth,  citron-coloured 
in  the  middle ;  extremities  white ;  eyes 
variable  in  form;  horn-like  processes 
slightly  elongated.  Found  amongst  Os- 
cillatoriae.     1-70". 

P.  aculeata. — White,  pro^-ided  with 
soft  spines ;  eyes  round.  The  tactile  tube 
(antenna)  is  thickened  anteriorly  m  a 
globose  manner;  the  jaws  have  each  three 
teeth,  (xxxv.  487,  488  represent  this 
animalcule;  and  489  the  jaws  and  teeth 
separate.)     1-70". 

P.  megalotrocha. — White;  body  smooth 
and  short;  wheels  large;  the  proboscis 
between  them  long;  eyes  oval ;  jaws  two- 
toothed.  Two  straight  setse  at  the  end 
of  the  tail.     1-216"  to  1-108". 

P.  hirsuta.  —  Of  a  pale  yellow  co- 
lour, and  covered  with  a  short  down  ; 
eyes  oblong;  foot  prolonged  by  dorsal 
spines;  viviparous.  Length  1-72";  of 
egg  1-480".     Berlin. 

2z 


'OG  SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


FAMILY  VIII.— BEACHI0:N^/EA. 


The  concluding  family  of  the  Rotatoria,  Brachion^a,  is  distinguished  by 
its  members  having  two  rotai7  organs  and  a  lorica. 

The  lorica  is  open  at  the  extremities,  like  a  tortoise's  carapace.  The  rotary 
apparatus  is  often  apparently  composed  of  five  parts,  three  central  and  two 
lateral ;  of  which  the  latter  alone  belong  actually  to  it,  the  others  being  only 
ciliated  frontal  portions,  which  during  the  vibration  of  the  trochal  disc  remain 
stiffly  extended  as  feelers.  Besides  these  appendages,  the  disc  presents  in 
most,  perhaps  in  all  the  species,  two  setae,  as  is  seen  also  in  Synchceta.  The 
genera  Noteus  and  Brachionus  have  a  forked  foot,  Anurtea  is  destitute  of 
feet ;  and  Pterodina  has  a  suctorial  disc  at  the  end  of  the  foot,  but  no  toes. 
All  the  genera  have  jaws,  with  teeth  attached  to  an  oesophageal  head,  having 
four  muscles.  In  Pterodina  the  jaws  are  partly  two-toothed  and  the  teeth  in 
a  line  (zygogomj^hia,  lochogomphia),  in  the  other  genera  they  are  many- toothed 
{fohjgompMa).  In  Noteus  and  Pterodina,  the  alimentary  canal  is  constricted, 
forming  stomachs  (gasterodela) ;  in  the  rest  it  is  partly  simple  {ccelogastrica), 
partly  with  stomachs.  Glands  have  been  observed  in  aU  the  genera,  as  also 
an  ovary  and  contractile  vesicle.  Many  species  of  Anurcea,  Brachionus,  and 
Noteus,  carry  their  eggs  attached  to  them,  after  expulsion.  In  aU  the  genera, 
except  Pterodina,  internal  tremulous  tags  attached  to  the  water-vascular 
canals  have  been  observed.  A  nervous  system  is  supposed  to  be  indicated  by 
the  presence  of  red  visual  points  in  aU,  except  Noteus,  which,  however, 
possesses  what  is  believed  to  be  a  cerebral  ganglion. 

Some  of  the  Brachionaea  may  become  so  numerous  as  to  render  the  water 
milky  and  turbid. 

Ehrenberg's  classification  of  this  family  is  given  at  p.  479. 

It  was  amongst  the  Brachionaea  that  some  of  the  most  interesting  of  recent 
investigations  were  first  made  by  Perty,  Cohn,  and  Leydig.  Thus,  striped  or 
voluntary  muscles  have  been  noticed  in  Brachionus  militaris  by  Cohn,  and  in 
Pterodina  by  Leydig ;  whilst,  in  the  latter  case,  the  same  distinguished 
observer  alleges  that  he  finds  a  refracting  body  in  the  eye  similar  to  what  he 
had  detected  in  Eucldanis  and  Stephanops.  In  Brctchionus  urceolaris  and 
militans,  again,  Perty  and  Cohn  have  established  the  existence  of  dioecious 
sexuality  amongst  the  Rotatoria — the  male  animal,  as  in  the  previously  de- 
scribed dioecious  forms,  being  devoid  of  an  alimentary  canal ;  and  to  this  list 
Mr.  Gosse  has  since  added  B.  Pala,  B.  ruhens,  B.  ampMceras,  B.  angidaris, 
B.  Dorcas,  and  B.  Mulleri.  Its  rarity,  and  the  comparatively  short  period  of 
time  during  which,  according  to  Perty,  the  male  animalcule  of  Brachionus 
urceolaris  exists,  probably  explain  why  these  creatm^es  have  been  so  long  over- 
looked. Cohn  observed  that  the  contractions  and  expansions  of  the  contrac- 
tile sac  at  the  base  of  the  water- vascular  canals  of  Brachionus  militaris  were 
accompanied  by  a  corresponding  motion  in  their  watery  contents.  At  each 
contraction,  or  systole,  a  stream  was  expelled  into  the  cloaca,  communicating 
with  the  water  in  which  the  creature  lived,  whilst  an  opposite  movement 
attended  the  expansion  or  diastole  of  the  sac.  These  facts  strongly  corro- 
borate the  supposition  that  the  water-vascular  canals  are  the  true  respiratory 
organs  of  the  Rotifera,  corresponding  with  the  remarkable  analogous  organs 
arising  from  the  cloaca  of  the  Holothunm  amongst  the  radiated  animals ;  the 
pure  oxygenated  water  being  thus  carried  to  the  fiuid  distending  the  body, 
which  fulfils  the  functions  of  the  blood  in  higher  animals,  and  affording  an 
example  of  the  "  Phlebenterism"  of  the  French  naturalist  Quatrefages. 

In  Brachionus  militaris,  Cohn  has  also  pointed  out  the  existence  of  three 


OF  THE  BEACHION^EA. 


707 


distinct  classes  of  eggs — viz.  winter,  summer,  and  male  ova- 
their  form  and  aspect. 


-all  differing  in 


Genus  NOTEIJS  (XXXV.  491-494;  XXXYIII.  25).— Eyes  absent;  foot 
furcate  (Brachmii  wanting  eyes).  The  two-wheeled  trochal  disc  has  between 
its  portions  a  three-lobed  ciliated  brow,  but  has  no  long  bristle-like  feelers ;  it 
possesses  (as  also  does  the  furcate  foot)  distinct  muscles.  The  lorica  has  spines 
both  anteriorly  and  posteriorly ;  an  oesophageal  head  with  jaws  having  many 
teeth  (poli/gomphia),  a  constricted  alimentary  canal  or  stomach  (gasterodela) 
with  two  large  glands,  an  ovarium,  and  a  contractile  vesicle  are  to  be  recog- 
nized. There  is  also  a  trace  of  tremulous  tags,  a  short  and  thick  water- 
vascular  tube,  and  a  large  central  ganglion,  lying  between  the  muscles  of  the 
vibratory  organs.  Dujardin  considers  the  absence  of  eyes  insufficient  to 
constitute  this  a  genus  apart  from  Brachionus. 

NoTEUS  quaclricornis  (xxxv.  491-494 ; 
xxxvin.  25).  —  Lorica  suborbiciilar,  de- 
pressed, rough  and  m'ceolated,  with  fom* 


siphon  between  the  large  spines  on  the 
front  of  the  body.  This  animalcule  is 
large,  very  transparent,  and  of  a  whitish 
colom-.  (xxxv.  491-493  represent  dorsal, 
ventral,  and  side  views ;  and  494  the 
jaws  separate,  and  under  pressm'e.) 
Found  amongst  decayed  sedge-leaves 
and  Oscillatorise.     1-120"  to  1-72". 


spines  anteriorly  and  two  posteriorly. 
Rotary  organ  simple,  with  a  deep  oral 
fossa ;  three  lobes  on  its  free  surface. 
Alimentary  canal  as  in  Brachionus.  A 
contractile  sac  on  the  right  of  the  cloaca 
giving  off  two  canals,  each  bearing  three 

Genus  ANUR-^A  (XXXV.  495-498).— Brachionaea  with  a  single  cer\ical 
eye,  but  no  foot  {Brachioyii  without  feet).  In  seven  species  the  lorica  has 
four  longitudiual  rows  of  facettes  upon  the  back ;  in  three  it  is  smooth ;  in. 
thirteen  species  it  is  spinous  anteriorly,  and  in  seven  posteriorly  also.  A. 
biremis  has  a  moveable  spine  on  each  side  :  of  one  species,  only  the  empty 
shell  has  been  seen ;  in  the  rest  the  muscles  of  the  rotary  organ,  but  not  the 
longitudinal  muscles  of  the  body,  have  been  observed.  Jaws  and  teeth  are 
seen  in  nine  species.  Alimentary  canal  constricted  {gasterodela)  in  four ; 
simple  and  conical  (coelogastrica)  in  nine.  Two  glands  are  placed  at  the 
commencement  of  the  alimentary  canal ;  an  ovary  is  seen  in  twelve  species, 
but  a  contractile  vesicle  only  ia  one  of  the  larger  and  smooth  species,  in  which 
also  four  tremulous  tags  are  found.  In  three  species  siphons  emanate  from 
the  neck.  The  eye-speck,  which  is  always  present,  is  supposed  to  indicate 
the  existence  of  a  nervous  system.  In  A.  squaniula,  A.  curvicornis,  A.  biremis, 
A.  striata,  and  A.  foliacea,  what  is  thought  to  be  nervous  matter  is  seen  below 
it.  Eight  species  have  their  eggs  attached  to  them  after  they  are  expelled. 
They  swim  freely,  though  not  very  quickly.  This  genus  has  the  name  of 
Anourella,  given  to  it  by  Bory  St.-Vincent,  and  retained  by  Dujardin. 

a.  Species  posteriorly  devoid  of  spines  a7ul  pedicle. 


Anttrjea  (?)  quadridentata. — Lorica 
oblong,  with  four  homs  anteriorly,  its 
posterior  end  obtuse,  back  tessellated. 
1-216"  without  the  homs. 

A.  Squamida  (Brachionus  Squamula, 
M.). — Smooth,  obtusely  square,  with  six 
horns  in  front,  obtuse  behind,  (xxxv. 
495-497  represent  different  views  of  this 
animalcule,  the  two  latter  with  an  egg 
attached.)     1-240". 

A.falcata. — Oblong  ;  with  six  spines 
anteriorly,  the  two  central  of  which  are 


curved  outwards,  like  sickles.  Sm'face 
of  the  lorica  not  ridged,  but  rough  ;  pos- 
terior extremity  obtuse.     1-144". 

A,  curvicornis. — Nearly  square,  with 
six  frontal  horns,  the  two  middle  ones 
larger  and  curved  outwards  and  down- 
wards. Dorsal  surface  tessellated ;  its 
large,  red,  roimd  eye  is  seated  upon  a 
large  nervous  ganglion  ;  the  oesophageal 
bulb  has  three-toothed  jaws.  This  ani- 
malcule also  canies  the  eggs  attached. 
1-216". 

2z2 


708 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


A.  hiremis. — Linear  and  elongated, 
with  four  horns  anteriorly;  back  very 
smooth,  and  having  two  lateral  spines, 
like  oars.  The  oesophageal  head  has 
three-toothed  jaws.  In  phosphorescent 
sea-water.     1-144". 

A,  striata  (Brachio?ius  striatm,  M.). — 
Linear  and  elongated,  with  six  horns  in 
front,  and  fom*  on  the  abdominal  surface 
of  the  lorica;  the  back  with  twelve  longi- 


tudinal flutings  or  rays,  and  obtuse  at 
the  end.  This  species  is  very  change- 
able in  form,  owing  to  the  membranous 
lorica  ;ydelding  to  the  contraction  of  the 
body :  hence  it  is  sometimes  long,  at 
others  short,  sometimes  urn-shaped,  bell- 
shaped,  and  even  almost  disc-shaped ; 
the  first,  however,  seems  to  be  the  normal 
foi-m.     Li  fresh  and  salt  water.    1-130". 


b.  Spinous  or  attenuated  ])osteriorly . 


A.  inermis. — Lorica  oblong,  attenuated 
and  truncated  posteriorly ;  no  spines  an- 
teriorly ;  back  furnished  with  faint  longi- 
tudinal rays.  In  peat-water.  Length 
when  extended,  1-144". 

A.  acuminata. — Lories  oblong,  attenu- 
ated and  truncated  at  the  posterior  extre- 
mity, having  anteriorly  six  sharp-pointed 
horns  or  spines,  twelve  longitudinal  rays 
on  the  back.  Amongst  Confervas. 
Length  about  1-120". 

A.  foliacea. — Lorica  oblong,  six  spines 
anteriorly,  posteriorly  terminating  in  a 
spine ;  dorsal  and  ventral  surfaces  longi- 
tudinally striated ;  frontal  region  rough. 
It  has  four-toothed  jaws,  and  a  central 
ganglion  below  the  eye.     1-180". 

A.  stipitata  (Brachionus,  M.). — Lorica 
nearly  square,  or  triangular;  anteriorly 
six  spines  ;  posterior  pointed  like  a 
pedicle  ;  the  back  tessellated,  (xxxv. 
498  represents  a  dorsal  view,  with  the 
wheels  extended.)  Length  about  1-200". 

A.  Testudo. — Lorica  square,  having 
anteriorly  six  straight  spines,  all  of 
nearly  the  same  length,  and  posteriorly 
a  short  one  at  each  corner.  The  upper 
and  under  surfaces  are  rough,  the  former 
tessellated  like  Noteus,  Length  about 
1-200". 


A.  serndata.  — Lorica  ovate,  square, 
with  six  unequal  spines  anteriorly,  the 
two  middle  ones  long  and  curved ;  it  has 
two  short  spines  at  the  posterior  angles, 
which  are  sometimes  scarcely  apparent. 
The  surfaces  are  rough,  and  the  dorsal 
also  tessellated,  like  the  preceding  species. 
Independently  of  the  two  wheels,  the 
brow  has  three  cylindrical  ciliated  pro- 
cesses, which  are  truncate  at  their  extre- 
mities.    1-216". 

A.  aculeata  (BracTiionus  quadratus, 
M.). — Lorica  square,  with  six  spines  an- 
teriorly, the  two  middle  longest ;  at  the 
posterior  angles  are  two  long  and  equal 
spines  ;  back  rough  and  tessellated,  under 
side  smooth.  At  the  brow,  between  the 
two  wheels,  is  a  single  ciliated  frontal 
process ;  a  little  tactile  organ  is  situated 
in  front  of  the  eye.  Length  1-144" ; 
including  the  spines,  1-96". 

A.  valga. — Lorica  nearly  square,  with 
six  spines  anteriorly,  the  two  middle 
ones  the  longest ;  at  each  posterior  angle 
is  a  spine  of  unequal  length ;  dorsal  and 
ventral  surfaces  rough,  the  former  tessel- 
lated. The  jaws  are  five- toothed,  the 
red  eye  oval,  its  longer  axis  transverse. 
Length,  without  the  spines,  1-210". 


The  following  species  are  given  by  Mr.  Gosse  (Ann.  Nat.  Hist.  1851,  vol.  viii.). 


A^Jlssa  (Gosse). — Lorica  smooth,  hya- 
line, swollen  at  the  sides  and  at  the 
back;  flattish  on  the  belly,  truncate  in 
front,  without  any  spines,  attenuated 
and  truncate  posteriorly.  There  is  a 
deep  fold  running  down  each  side,  or 
else  the  ventral  plate  is  distinct  from  the 
doi-sal ;  the  ventral  is  also  cleft  through 
its  medial  line  j  eye  very  large,  pale. 
1-220". 

A.  tecfa  nearly  agrees  in  form  with 
A.  eurvieornis;  but  the  posterior  extre- 
mity is  rather  more  pomted,  and  the 
tessellations  are  difi'ereut,  being  larger, 
and  arranged  on  each  side  of  a  medial 
dorsal  ridge,  which  gives  to  the  back 
the  form  of  a  vaulted  roof.     1-200". 


A.  hrevispina  nearly  agrees  with  A. 
aculeata ;  but  the  posterior  spines  are  very 
shoi-t,  the  frontal  spines  are  much  less 
curved    forwards,    the    sm-face    is   not 
punctated,  and  it  is  colourless.     1-146". 
A.    cochlearis. — Lorica   spoon-shaped, 
with  six  spines  in  front,  the  medial  pair 
curving  strongly  forwards ;  posterior  ex- 
tremity attenuated  into  a  long  slender 
spine,   inclined  forwards  ;   back  ridged 
and  tessellated,  as  in  A.  tecta. 
!      A.  heptodo7i  =  Ascomo?pha    Helvetica, 
I  Perty.  —  Lorica   of  equal  width,    con- 
j  tracted  posteriorly,  and  terminated  by  an 
j  upturned  tooth  in  the  middle  line.     In 
front  are  four  teeth  above  and  two  below. 
'  1-12".     This   species,   founded   on   one 


OF  THE  BRACHIOXJiA. 


ro9 


individual  example,  vesemhlesA.foliacea,  I  the  peculiar  upturned  tooth  iu  the  median 
but  is  less  flat,  more  cubical,  and  possesses  |  line,    (xxxviii.  (5.) 


Genus  BRACHIOiS'US. — Brachionsca  which  have  a  single  cervical  eye  and 
a  furcate  foot.     Figure  compressed.     Lorica  closed  at  the  sides ;  open  at  the 
extremities  like  a  tortoise-shell.     Anterior  and  posterior  margins  usually 
dentate ;  sm^face  either  smooth  or  rough  and  tuberculated,  the  tubercles  on 
the  abdominal  surface  arranged  in  four  lines  diverging  posteriorly.     The 
cuticle,  which,   according   to  Leydig,   rests   on   a   molecular   layer,  resists 
Uquor  potassse.     The  frontal  processes  or  teeth  are  dentate  on  their  inner 
edge.     Animal  able   to  withdraAV  itself  within  the  lorica.     Rotary  organ 
simple,  and,  though  often  looking  as  if  lobed,  presenting  an  unbroken  border, 
except  when  it  is  indented  by  descending  to  the  mouth,  whence  this  bilobed 
aspect ;  a  median  lobe  and  two  lateral  ones  arise  from  its  free  surface.     On 
its  right  and  left  side  are  some  eminences  surmounted  by  long  bristles,  in 
addition  to  a  long  bristle  projecting  backwards  from  each  lateral  margin  of 
the  rotary  organ.    A  granular  mass,  the  supposed  cerebral  ganglion,  supports 
the  eye-speck,  which  is  extended  backwards  into  two  points.     A  siphon,  or 
tactile  tube,  tenninated  by  a  bunch  of  setse,  projects  from  between  the  an- 
terior median  teeth  of  the  lorica.     Two  brown  vesicles  in  front  of  the  large 
muscular  oesophageal  bulb,  in  which  are  the  toothed  jaws ;  a  short  oesopha- 
gus ;  and  a  stomach,  the  latter  composed  of  coloured  cells,  ciliated  on  their 
free  surface.     In  front  of  the  stomach  two  pedunculate  glands.     Intestine 
clear  and  ciliated.     Contractile  vesicle  on  the  right  of  the  cloaca,  with  two 
water-vascular  canals  proceeding  from  it  to  the  neck,  where  they  form  a 
plexus  and  bear  two  tags.     Ovary  beneath  the  stomach.     Eggs,  according  to 
Perty,  of  three  sorts,  viz.  winter  ova,  summer  ova,  and  ova  bearing  male 
embryos.    Ova  attached  to  the  exterior  of  the  animal.    B.  Pala,  B.  urceolaris, 
and  B.  ruhens  sometimes  increase  in  such  quantities  as  to  render  the  water 
milky  and  turbid.     Several  species  are  infested  with  VorticeUa,   Ejjistylis, 
and  other  parasites,  which  attach  themselves  to  their  sheUs.   Like  Asplanchna, 
EucJilanis,  and  others,  the  genus  Brachionus  has  acquii^ed  great  additional 
interest  from  the  discovery  amongst  some  of  its  species  of  the  distinct  sepa- 
paration  of  the  sexes.     The  male  Brachioni  present  a  different  form  to  that 
of  the  female,  resembling,  in  this  respect,  AsjpIancJina  Sieboldii  rather  than 
A.  Brlghtwellii  and  Hydatina  senta,  in  which  the  difference  of  external  con- 
tours is  mainly  one  of  size.     The  multiplying  discoveries  of  separate  sexes 
amongst  the  Rotifera,  combined  with  the  manifest  absence  of  male  organs 
in  the  numerous  individuals  provided  with  ovaries,  renders  it  increasingly 
probable  that  all  the  Rotifera  will  finally  be  demonstrated  to  be  bisexual  or 
dioeceous. 


Brachionus  Pala.  —  Lorica  smooth, 
with  four  spines  in  front,  and  two  obtuse 
ones  near  the  opening  for  the  foot.  Toes 
of  the  foot  apparently  bifid.  This  crea- 
ture swims  m  a  perpendicular  position, 
the  brow  being  directed  upwards.  Each 
jaw  has  five  teeth ;  the  alimentary  canal 
being  constricted,  forms  a  stomach. 
Length  1-36" ;  lorica  only  1-48"  (xxxix. 
14,15).  :i  y 

B.  amphiceros. — Has  a  smooth  lorica, 
with  four  spines,  in  front  and  poste- 
riorly ;  four  sharp  posterior  teeth  are 
characteristic.     1-72". 


B.  w'ceolans  (Brachiorms  urceolarts, 
M.). — Whitish  ;  lorica  smooth,  with  six 
very  short  spines  in  front ;  posterior  ex- 
tremity rounded ;  lorica  slightly  granu- 
lated ;  its  points  are  shorter  and  less 
sharp  than  in  the  following  species  ; 
delicate  longitudinal  ridges  proceed  from 
the  spines ;  the  jaws  have  each  five 
teeth. 

The  males  of  Brachionus  urceolaris, 
according  to  Perty,  are  developed  from 
smaller  ova  than  the  females,  these  eggs 
being  also  adherent  to  the  parent  in 
greater  numbers.     They  are  very  splie- 


710 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


rical,  reacliing  1-50'"  in  lenoili  and  1-67'" 
in  diameter.     Their  shell  is  more  deli- 
cate and  the  contents  clearer  and  more 
transparent,  as  well  as  of  a  pale  yellowish 
hue  instead  of  the  dusky  gTey  of  the 
female  ova.    The  former  likewise  contain 
fewer  gTanules.     The   development  by 
fission  similar  in  both.     When  the  egg- 
is  mature,  it  continues  to  be  pale  and 
transparent.   The  red  eye-speck  exhibits 
itself  5  but  the  maxillary  apparatus,  seen 
in  the  female  ovum,  is  wanting.    On  the 
other  hand,  two  or  three  heaps  of  dark 
gi-anides  occur,  not  seen  in  the  females. 
The  embryo    escapes   from   the    ovum 
by   a  transverse   rupture,   and  is   then 
seen  to  have  a  different  contoiu*  from 
the   female.      It   is  but   one-third   the 
size  of  the  latter,  being,  when  extended, 
but   1-27'"  to   1-22'"  long,    and    from 
1-60"'  to  1-55'"  broad.     It  is  destitute 
of  a  firm  lorica  -,  short,  cylindrical ;  pro- 
longed   anteriorly   into    a    short    head, 
separated   by  a  constriction  from    the 
trunk ;  prolonged  posteriorly  into  a  short 
tubular  foot  about  one-fifth  the  length 
of  the  body.     Head  crowned  by  a  flat- 
tened disc,  with  a  wide  expanding  mar- 
gin, clothed  mth   long  vibrating   cilia 
and  a  few  non-^dbratile  bristles.     Cilia 
moving  with  extraordinary  velocity'-,  pre- 
venting many  being  seen  at  once ;  but  a 
little   strychnine    added   to    the   water 
checks  their  action  and  facilitates  their 
observation.  No  mouth  is  present;  hence 
the  ciliary  wreath  is  not  twined  inwards 
at  the  oral  fissm-e ;  the  alimentary  appa- 
ratus is  wholly  wanting.     A  large  pp'i- 
fonn  vesicular  testicle,  1-100'"  in  length, 
occupies  the  middle  of  the  body ;  it  is 
filled  with  small  dark  moving  sperma- 
tozoa.    The  wall  of  the  testicle  is  very 
thick,  and  elongated  at  its  upper  extre- 
mity into  a  thick  cylindi'ical  band,  which 
is  attached  to  the  cephalic  disc.     Pos- 
teriorly the  testicle  is  sti'iated  longitu- 
dinally, and  is  perforated  by  an  aperture 
opening  into  a  wide  spermatic  duct  con- 
ducting to  the  penis.     The  latter  organ 
is  a  short  tube  usually  laid  free  on  the 
foot  and  nearly  extending  to  its  extre- 
mity ;  its  internal  canal  and  outer  mar- 
gin equally  fiu-uished  with  vibratile  cilia. 
The  foot  is  transversely  wrinkled,  and 
ends  in  two  small  toes.     Near  the  root 
of  the  penis  are  two  club-shaped  glands 
which  pour  their  secretion  into  its  canal ; 
near  these  is  also  a  contractile  vesicle 
with   two   water-canals   and   their   ap- 
pended tags.     Several  spherical  cell-like 
bodies  occur  near  the  head, — the  larger 
of  these,  the  supposed  cerebral  ganglion, 


supporting  the  eye-spot.  Two  or  three 
vesicles  of  imcertain  character,  filled 
Tvith  dark  granules,  rest  on  the  testicle 
near  its  lower  end.  The  males  are  much 
rarer  than  the  females,  and  are  not  seen 
after  the  end  of  May.  In  fresh  and 
brackish  waters.  Length  of  females 
from  1-96"  to  1-72".  (xxxix.  10-20; 
XL.  20-23.) 

B.  rubens  (JB.  urceolaris,  M.). — Lorica 
smooth,  with  six  sharp  spines  in  front, 
posteriorly  roimded;  the  body  is  red. 
1-50".  Diijardin  supposes  this  to  be  a 
variety  of  B.  urceoJaris.  Ley  dig  recog- 
nizes its  distinctness,     (xxxvni.  7.) 

B.  Iliillen  {Miiller^s  Urachionus).  — 
Lorica  smooth,  with  six  obtuse  spines  in 
fi'ont,  two  short  ones  behind,  resembling 
papillae.  This  species  is  somewhat  larger 
than  B.  urceolaris,  and  has  peculiarly- 
shaped  frontal  spines.  The  margin  of 
the  chin  (brow)  is  smoothly  truncate, 
with  three  faint  indentations.  The  lorica 
is  very  transparent.  1-60".  According 
to  Mr.  Gosse,  the  B.  hq)tatomus  found  in 
sea-water  is  identical  with  this  species. 
(xxxix.  13.) 

B.  hrevisphuis. — Lorica  smooth,  having 
six  acute  unequal  spines  in  fi'ont,  and 
four  stout  spines  posteriorly,  the  two 
inner  ones  short ;  two  sexual  glands  and 
a  contractile  vesicle  are  present.  In 
slow  running  clear  water,  with  Con- 
fen^se.     1-65". 

B.  Bakeri  (M.). — Lorica  rough,  its 
middle  tessellated  on  the  dorsal  smface ; 
six  unequal  acute  teeth  anteriorly,  two 
elongated  (lateral  and  dorsal)  spines 
posteriorly,  and  short  ones  at  the  sheath 
of  the  foot.  The  lorica  is  covered  with 
delicate  granules  ;  those  upon  the  middle 
of  the  ventral  surface  are  aiTanged  in 
parallel  but  somewhat  curved  lines. 
1-220"  to  1-60".  (xxxvm.  8,  9,  10-17 ; 
XL.  16.) 

"The  following  interesting  observa- 
tions as  to  the  development  of  this  spe- 
cies have  been  commimicated  to  me  by  a 
friend,  an  accurate  and  diligent  observer 
of  natui'e : — About  two  o'clock  B.  Ba- 
keri was  observed  with  one  egg  placed 
externally  between  the  two  posterior 
spines  of  the  shell,  and  another  small 
egg  in  the  left  side  of  the  animal,  which 
increased  much  in  size  in  the  course  of 
the  day.  At  nine  in  the  evening_  a 
motion  was  perceived  in  the  exterior 
egg  like  that  of  the  muscular  oesophagus 
of  the  parent;  and  about  this  time  the 
internal  egg  was  protruded  and  placed 
by  the  side  of  the  other,  being  longer 
than  it.    At  eleven  the  young  Brachionus 


OF  THE  BEACHIONJ£A. 


711 


burst  with  a  bound  from  the  egg  in 
which  the  motion  was  perceived,  and 
afiLxed  itself  by  its  tail  to  the  lunette. 
At  first  it  hai  the  appearance  of  an 
oblong  ball ;  by  degrees  the  anterior  part 
spread,  and  fhe  wheel  processes  were 
developed.  Soon  after,  the  posterior  shell- 
processes  were  visible  in  a  semilunar 
shape,  with  the  points  nearly  touching 
each  other,  which  gradually  expanded. 
The  shell  of  the  egg  remained  attached 
to  the  parent  in  the  same  position,  quite 
transparent,  with  a  longitudinal  split 
through  the  whole  length."  (Brightwell, 
op.  cit.) 

B.  polyacanthus  (M.). — ^Lorica  smooth, 
ha^-ing  anteriorly  fom'  long  dorsal  teeth 
or  spines,  six  short  ones  at  the  margin 
of  the  chin  (ventral),  and  posteriorly 
five  dorsal  spines,  the  two  external  or 
lateral  ones  very  long.  xxxv.  499-501 
represent  dorsal,  side,  and  imder  ^-iews 
of  this  animal, — the  first  having  the 
wheels  extended,  and  the  side  view 
showing  the  siphon  or  so-called  respi- 
ratory tube  and  an  ovimi  attached. 
Length,  without  spines,  1-110".  xxxvin. 
14,  15  represent  diagTams  of  the  head. 

B.  miJitaris.  —  Lorica  ^^dth  surface 
divided  into  tw^elve  regular  pentagonal 
facettes,  according  to  Cohn;  its  anterior 
border  with  several  spinous  processes  j 
and  posteriorly  is  a  deep  median  ex- 
cavation with  a  curved  horn  on  each 
side.  The  spines,  10  in  number  (not  12 
as  afiirmed  by  Ehrenberg),  viz.  2  lateral, 
4  abdominal,  and  4  dorsal,  the  latter  the 
largest ;  head  larger  than  that  of  B.  ur- 
ceolaris,  expanded  in  a  funnel-shaped 
manner,  surroimded  by  a  circlet  of  cilia  ; 
its  eversion  is  checked  by  the  stifi'  spines 
of  the  lorica.  Foot  smaller  and  shorter 
than  in  B.  urceolaris.  OEsophageal  bulb 
quadrangidar.  On  each  spine  forming 
the  outer  posterior  angle  of  the  lorica  is 
a  circular  pit  with  well-defined  margin ; 
from  this  proceeds  a  bimch  of  short 
bristles.  Muscles  of  foot  and  head  striped 
transversely.  Contractile  sac  very  large, 
occupying  two-thirds  of  the  abdominal 
cavity  on  the  right  side  of  the  animal ; 
it  consists  of  two  chambers,  the  ovate 
posterior  one  being  the  larger,  their  con- 
tractions being  alternate  ;  the  posterior 
one  opens  into  the  cloaca  by  a  short 
duct.   On  mingling  colom^ed  matter  with 


the  water,  Colin  observed  that  on  each 
systole  or  contraction  a  stream  escaped 
from  the  sac,  through  the  cloacal  open- 
ing, and  that  on  the  diastole  this  move- 
ment was  reversed,  indicating  a  respi- 
ratory action,  (xxxix.  21,  22  represent 
the  abdominal  and  dorsal  surfaces  of  the 
female.)  The  ova  are  of  three  sorts : — 
1.  Winter  ova,  1-21'"  long,  1-33"'  wade, 
elliptic,  with  thick,  leathery,  opaque 
walls,  the  yelk  not  occuppng  the  poles 
(xxxix.  23)  j  2.  Ordinary  or  summer  ova, 
of  similar  dimensions,  but  with  thin 
transparent  walls  ;  3.  Male  ova,  only 
1-34"'  long  and  1-42'"  broad  (xxxix. 
24).  Shell  thin.  Yelk  subdividing  in 
the  usual  way,  and  developing  an  em- 
bryo provided  with  a  red  eye,  and  two 
dark  specks,  but  no  maxiUary  organs. 
Cohn  saw  only  one  specimen  freed  from 
the  egg,  and  that  imperfectly.  It  ap- 
peared similar  to  the  male  of  B.  ur- 
ceolaris. 

B.  Oon  (Gosse).  —  Lorica  ovate,  the 
back  swelling  with  a  unifonn  ciu've,  by 
which  it  is  distinguished  from  B.  Paki, 
which  is  truncate  or  slightly  clavate 
posteriorly ;  anterior  spines  fom-,  straight, 
wide  at  the  base,  and  pointed ;  the  occi- 
pital pair  taller  than  the  lateral.  Lorica 
1-125". 

B.  Dorcas. — Lorica  ovate  or  sub-coni- 
cal ;  occipital  edge  with  four  long  slender 
spines,  the  middle  pair  cm^v-ing  forwards, 
and  bent  first  from,  and  then  towards 
each  other,  like  the  horns  of  an  antelope ; 
mental  edge  undulated,  with  a  notch  in 
the  centre.  Lorica  1-60".  (xl.  11  re- 
presents a  newly-bom  female,  and  fig.  12 
a  newly-bom  male.) 

B.  angidaris.  —  Lorica  in  the  female 
hexagonal-oval  in  the  dorsal  aspect ;  occi- 
pital edge  with  two  small  teeth,  divided 
by  a  roimded  notch  (in  some  specimens 
there  are  obsolete  traces  of  a  lateral 
pair)  ;  mental  edge  slightly  undulated, 
sometimes  wdth  two  low  points,  divided 
by  a  notch  like  the  occiput,  but  still 
more  faintly;  posterior  extremity  with 
tw^o  short,  blunt,  weU-marked  processes. 
The  general  smface  is  roughened  "vvdth 
angular  ridges,  and  is  sometimes  sub- 
opaque  and  browTi.  Lorica  1-200".  This 
cm-ious  species  has  relations  with  Noteus 
and  with  Pterodina.  (xi/.  19  represents 
a  male  of  this  species. ) 


Genus  PTEEODIN'A. — The  winged  Rotatoria  include  such  Brachionaea  as 
have  two  frontal  eyes  and  a  simple  styliform  foot  projecting  from  the  middle 
of  the  body.  AU  the  species  have  a  smooth,  flat,  and  soft  lorica,  like  a  tor- 
toise-shell, with  curv'ed  margins  ;  as  also  a  more  or  less  double  rotaiy  appa- 


12 


SYSTEMATIC  HISTORY  OF  THE  I^EUSOKIA. 


ratus,  and  a  simple  foot  with  a  suction-disc  and  sometimes  a  bunch  of  cilia 
at  its  extremity.  P.  elliptica  has  a  hairy  process  projecting  between  the  two 
lobes  of  the  rotary  organ,  and  P.  Patina  has  a  rounded  prominence  in  a  similar 
position  on  the  dorsal  surface.  Muscles,  often  transversely  striated,  occur  in 
all  the  species,  as  also  a  constricted  alimentary  canal  with  glandular  appen- 
dages and  an  ovarium.  Some  have  a  contractile  vesicle  and  a  water-vascular 
system. 


Pterodina  Patina  (Brachionus  Pa- 
tina, M.). — Figure  roimd,  or  oval  com- 
pressed. Lorica  membranous,  crystal- 
line, somewhat  scabrous  near  its  broad 
margin,  and  slightly  excavated  anteriorly 
between  the  two  lobes  of  the  rotary 
organ.  The  latter  not  double,  as  de- 
scribed by  Ehrenberg,  but  with  an  an- 
terior and  posterior  depression,  from  the 
latter  of  which  extends  a  single  rounded 
process.  Cilia  in  two  rows,  prolonged 
to  the  oesophageal  bulb.  Stomach  ciliated 
internally,  widely  expanded  posteriorly. 
Short  intestine  also  ciliated,  and  termi- 
nating at  the  base  of  the  foot.  Two 
pyriform  glands  in  front  of  the  stomach. 
Two  red  specks  opposite  the  margin  of 
the  rotary  organ  ;  their  red  pigment  has 
a  sharp  spherical  figure ;  according  to 
Leydig,  an  obvious  refracting  body  pro- 
jects from  the  anterior  convex  edge  of 
each.  Two  large  longitudinal  muscles. 
On  each  side  of  the  stomach  a  water- 
vascular  canal,  but  without  either  tags 
or  contractile  sac.  Ovary  horseshoe- 
shaped.  Free  extremity  of  the  foot  with 
a  bundle  of  setae. 

This  animal  was  noticed  by  Perty  to 
have  the  peculiarity  of  assuming  an  ap- 
parently lifeless  state  for  half  an  hour  or 


an  hoiu*  at  a  time,  lying  in  one  spot, 
often  on  the  smface  of  the  water,  with 
no  other  sign  of  life  than  that  afforded  by 
movements  of  the  oesophageal  cilia,  and 
occasionally  of  the  jaws. 

This  species  is  very  delicate  and  tran- 
sparent. XXXV.  502  represents  a  side 
view,  and  503,  504  under  views, — the 
latter  having  the  wheels  extended,  the 
former  having_  them  withdrawn,  and  the 
anterior  margin  bent  in,  so  that  the  eyes 
appear  near  the  middle  of  the  lorica. 
The  internal  organization  is  further 
shown  in  xxxvni.  29.  Foimd  in  sum- 
mer among  Lemnce  and  Ceratophylla. 
Leng-th  about  1-120". 

P.  elliptica. — Lorica  membranous,  el- 
liptical, with  a  narrow,  smooth  margin, 
front  entire  (not  excised).  The  two 
wheels  united  by  a  brow  fmnished  with 
setae.  Eyes  distant.  Amongst  Con- 
fervae.     1-120"  to  1-108". 

P.  clypeata  {Brachionus  clypeatus,  M.). 
— Lorica  membranous,  oblong,  naiTOw, 
smooth  at  the  margin ;  there  is  a  frontal 
portion,  or  brow,  connecting  the  two 
wheels,  but  no  setae.  The  eyes  approxi- 
mate, (xxxv.  505  a  dorsal  view,  with 
the  wheels  extended.)  In  sea-water. 
Length  1-120"  ^  the  shell  1-144". 


The  next  genus,  Pompholyx,  instituted  by  Mr.  Gosse,  is  considered  by  him 
to  be  a  member  of  this  family. 

Genus  POMPHOLYX  (Gosse,  A.  N.  H.  1851,  vol.  viii.).  —  Two  frontal 
eyes ;  foot  wanting ;  rotary  organ  double  in  the  rear,  entire  in  front ;  eggs 
attached  behind  after  deposition.  The  name  alludes  to  the  resemblance  of 
the  lorica  to  a  round  flat  smelling-bottle. 


PoMPHOLYX  complanata.  —  Lorica 
much  depressed,  nearly  circular,  with 
the  lateral  edges  rounded ;  anteriorly 
truncate  j  occipital  edge  gradually  rising 


to  a  central  blunt  point  j  mental  ridge 
with  two  rounded  lobes,  divided  by  a 
central  notch,     Lorica  1-300". 


Of  the  ensuing  genera,  established  by  Ehrenberg,  we  have  only  met  with 
the  description  of  species ;  of  one,  indeed,  with  only  a  sketch  of  its  relations. 

Genus  LARELLA  (Ehr.). — The  following  species  of  this  new  genus,  the 
characters  of  which  we  have  not  met  with,  is  named  by  Ehrenberg. 

Larella  Piscis.  —  Body  with  equal    eyes.    Length  1-190"  to  1-280".    Berlin, 
setae,  and  three  long  fine  hairs  placed  on    Wemeck  has  also  seen  this  species, 
each  side  the  mouth,  with  two  frontal 


OF  THE  TARDIGEADA.  713 

Genus  TETRASIPHON  (Ehr.).— We  have  not  met  with  the  detail  of  the 
generic  characters,  but  they  may  be  gathered  from  the  description  of  the 
following  species : — 

Tetrasiphon  Hydrocora.  —  Very 
large,  hyaline,  with  two  prominent  tu- 
bular occipital  organs,  and  other  two 
near  the  termination  of  the  back ;  pan- 
creatic glands  fom',  globose;  jaws  bi- 


dentate,  with  the  oblique  rotary  organ 
of  Pleurotrocha.  Foot  with  slender,  long 
and  acute  toes;  eye  occipital.  Length 
1-36"  and  upwards.    Berlin. 


Genus  DIPODINA. — Characters  unknown. 


DiPODiNA  Artiscon  (Ehr.)  (^lentioned 
in  Reports  of  Zoology,  Ray  Society). — 
Approaches  Notommata,  but  differs  by  a 


particular  constriction  of  its  tarsal  nip- 
pers (toes).  Found  by  Ehrenberg  at 
Wismar,  on  the  Baltic. 


The  genus  Polych^dtus  (XXXVIII.  31,  32)  of  Perty  is  supposed  by  Leydig 
to  be  a  Crustacean.  Ctphonautes  is  also  regarded  by  the  same  observer  as 
dubious ;  whilst,  as  we  have  already  observed,  he  regards  Ptygura  and  Gleno- 
phora  as  undeveloped  forms  of  other  species. 


OF  THE  GROUP  TARDIGRADA. 

The  creatures  thus  named  are  introduced  here  as  a  group,  inasmuch  as  they 
cannot  be  included  amongst  the  Rotatoria.  Some  remarks  on  their  organiza- 
tion will  be  found  in  Part  I.  (p.  482)  of  this  work ;  and  here  I  shall  introduce 
fm-ther  particulars,  chiefly  derived  from  the  first  edition  of  this  work  (1834), 
p.  182,  and  from  Dujardin's  Hist,  des  Tnfusoires,  p.  661.  They  have  oblong 
bodies,  contracted  into  a  baU;  furnished  with  four  pairs  of  short  feet  or 
mammilliform  processes,  each  terminated  by  simple  or  double  hooked  claws ; 
mouth  very  narrow,  siphon- shaped ;  with  an  internal  maxillary  apparatus 
composed  of  two  lateral  moveable  pieces,  and  of  a  strong  muscular  oesophageal 
bulb,  furnished  with  horn-like  dental  articulated  processes. 

The  Tardigrada  stand  on  the  one  side  between  the  Rotatoria  (Systolides, 
Duj.)  and  the  Helminthidas,  and  on  the  other  between  the  AnneKda  and 
Ai'achnida. 

These  creatures  are  usually  found  attached  to  aquatic  plants  which  float 
upon  still  water.  I  first  obtained  them  from  ponds  in  the  Regent's  Park. 
By  placing  some  water  with,  the  plants  in  a  common  white  hand-basin,  and 
shaking  the  vegetation,  they  are  detached  and  fall  to  the  bottom  of  the  basin, 
from  whence  they  are  readily  taken.  They  are  generally  met  with,  in  com- 
pany with  the  larger  kinds  of  Rotatoria,  in  moss.  They  are  very  sluggish  in 
their  movements,  and  are  commonly  knoT?VTi  under  the  name  of  "  little  water- 
bears."  Under  the  polarizing  microscope  the  manducatory  apparatus  exhibits 
the  same  appearance  as  horn.  They  are  capable  of  resuscitation  after  being 
dried.     They  vaiy  in  length  from  1-20"  to  1-50". 

M.  Doyere,  in  an  elaborate  Memoir  in  the  '  Annales  des  Sciences,'  has 
divided  the  Tardigrada  into  four  genera : — 

Genus  EMYDITIM. — Body  oval,  anterior  part  narrow,  and  terminating  in 
a  pointed  mouth,  near  to  which,  on  each  side,  are  flesh-like  papillje.     Feet 


714 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


armed  with  four  distinct  claws;  colour  reddish.   Eound  amona-  moss  (Bntum) 
(Figs.  1,2.)  ^     ^• 

Genus  MACROBIOTUS. — Body  more  cylindrical ;  obtuse  anteriorly ;  no 
setae ;  each  foot  furnished  with  two  claws.  Found  with  the  preceding ;  also 
in  rivulets.    (See  fig.  6.) 

Genus  TAEDIGEADA. — Body  stout,  oblong ;  mouth  not  so  sharply  pointed. 
Found  in  stagnant  water,  on  aquatic  plants,  and  on  the  Hypnum  fluitans. 
(See  figs.  3,  4,  5.) 

Genus  MILNESIUM. — Characters  unknown. 

For  further  particulars  consult  the  General  History,  at  p.  482  of  this  work. 

2  4 


TAEDIGEADA,  OE  LITTLE  WATEE-BEAES. 

Fig.  1.  Emydium,  magnified  130  diameters.  Fig.  2.  Head  of  the  same,  magnified  30(.) 
times.  Figs.  3,  4.  TarcZ^^^'raf^tt,  magnified  160  times.  Fig.  5.  Head  of  same,  magnified 
300  times.     Fig.  6.  Mouth  apparatus  of  Macrobiotics,  greatly  magnified. 


OF  THE  DESMIDIEiE.  715 


OF  THE  GROUP  BACILLARIA. 

Sub-group  DESMIDIE^  or  DESMIDIACE^. 
(Page  1,  Plates  I.,  II.,  III.,  XVI.) 

[Class  Alg^,  Order  Chlorosjpermece,  Family  Desmidiacece  of  Botanists.] 

Cells  of  two  symmetrical  valves,  devoid  of  silex,  mostly  figured,  their  junc- 
tion marked  by  a  pale  interruption  of  the  endochrome,  frequently  also  by  a 
constriction ;  increasing  by  the  formation  of  two  new  half-cells,  which  become 
interposed  between  the  older,  so  that  the  two  newly-produced  cells  consist 
each  of  a  new  and  an  old  half-cell ;  the  transverse  division  complete  or  incom- 
plete, the  cells  thus  either  free  or  forming  a  filament ;  endochrome  green, 
occasionally  converted  into  ciliated  zoospores  (in  the  single  known  instance, 
escaping  by  an  aperture  at  the  apex  of  one  or  more  specially  formed  lateral 
tubes)  ;  reproduction  by  conjugation  of  the  contents  of  two  distinct  cells,  and 
the  formation  of  sporangia,  the  contents  of  which,  in  after- development,  be- 
come segmented  into  a  definite  nimiber  of  individualized  portions,  the  last 
generation  of  which  are  set  free  by  the  bursting  or  solution  of  the  containing 
membrane,  and  become  the  first  fronds  of  a  new  vegetative  cycle. 

We  believe  the  foregoing  diagnosis  will  apply  to  and  include  all  the  species 
which  we  look  upon  as  undoubtedly  belonging  to  this  family,  and  which  are 
introduced  into  this  work.  The  claims  of  the  genera  Cylindrocystis  and 
Mesotaenium,  as  true  members  of  the  Desmidiaceae,  not  appearing,  so  far  as 
we  can  judge,  to  be  satisfactorily  established,  they  are  omitted. 

The  wonderful  variety  of  form  and  beautiful  symmetrical  diversity  of  out- 
hne  of  the  members  of  this  family  have  been  dilated  on  at  length  in  the 
General  History.  It  seems  to  us,  with  regard  to  the  mode  of  cell-division 
in  the  true  species  of  this  family,  that,  normally,  the  preliminary  step  in  the 
process  is  the  sej)aration  of  the  cell- contents  and  the  formation  of  a  septum 
at  the  central  sutiu^e,  the  two  halves  of  the  contents  becoming  thus  indi- 
vidualized, whereupon  ensues  the  growth  and  extension  of  the  primordial 
utricle  and  contents,  concm^rently  with  the  production  of  the  intermediate 
ceU-waU  ultimately  to  form  the  two  new  segments,  and  either  complete  sepa- 
ration taking  place,  or  the  cells  remaining  united  in  more  or  less  brittle 
filaments. 

Many  of  the  species,  probably  all,  seem  to  be  liable  to  an  abnormal  mode 
of  growth,  resulting  from  the  incomplete  carrying  out  of  this  process,  when 
the  new  growth  forms  an  intermediate,  frequently  misshapen  structure,  pro- 
ducing with  the  original  segments  but  one  uninterrupted  cavity, — this  irregu- 
larity seeming  to  be  primarily  due  to  the  omission  of  the  formation  of  the 
septum  on  the  recommencement  of  the  vegetative  growth  (III.  61,  Q2)  :  vide 
Mrs.  H.  Thomas,  J.  M.  Sci.  vol.  iii.  pi.  5.  figs.  17  &  18 ;  also  M.  de  Brebisson, 
Liste,  ifcc.  pi.  1.  fig.  15  ;  and  Mr.  W.  Archer,  Proc.  Nat.  Hist.  Soc.  Dub.  1859, 
vol.  ii.  pi.  1.  figs.  9-15.)  An  inspection  of  several  of  the  latter  figures  will, 
however,  show  that  the  intervening  structure,  in  the  first  instance  (from  the 
foregoing  cause,  as  we  imagine)  rendered  abnormal,  is  not  always  absolutely 
shapeless  or  irregular  in  its  form,  but  sometimes,  its  axis  of  growth  striking 
off  at  right  angles  to  that  of  the  older  segments,  assumes  the  form  and  often 
the  size  of  an  entire  frond.     Sometimes,  indeed,  not  only  is  the  axis  of  growth 


716  SYSTEMATIC  HISTORY  OF  THE  IJfFL'SOElA. 

at  right  angles  to  that  of  the  original  segments,  but  its  plane  of  expansion  is 
at  right  angles  to  their  plane.  In  each  of  these  latter  cases  the  entire  ab- 
normal specimen,  therefore,  forms  a  cross, — the  interior  here,  of  course,  as 
well  as  in  those  cases  where  the  intervening  growth  does  not  assume  any 
definite  outline,  making  but  one  uninterrupted  cavity  (III.  61).  The  omission 
of  the  formation  of  a  septum,  however,  can  only  be  looked  on  as  the  primary 
cause  of  the  aberration,  the  curious  change  in  the  direction  of  the  new  growth 
not  necessarily  following,  as  the  figures,  pi.  1.  f.  9-11  {loc.  c'lt.)  seem  to 
prove  (III.  62). 

The  assertion  that  zoospores  occur  in  this  family  is  based  upon  the  observa- 
tions made  by  Mr.  W.  Archer  on  Docidium  Ehrenhergii  (Rails),  and  recorded 
and  figured  in  Proceedings  Nat.  Hist.  Soc.  Dublin,  Febniary  1860 ;  also  Nat. 
Hist.  Review,  July  1860.      These  observations,  though  unfortunately  and 
unavoidably  not  so  full  in  their  details  as  the  interest  of  the  case  would  lead 
us  to  wish  for,  seem  to  warrant  the  assumption  that  the  species  of  this  family 
may  be  occasionally  propagated  by  zoospores,  predicating  of  the  family  that 
which  seems  to  hold  in  the  species  in  question  {Docidium  liJJirenheryii).    Pedi- 
astreae  are  of  course  not  taken  into  account.     Briefly,  the  phenomenon  alluded 
to  is  as  follows  (III.  46,  47)  : — From  beneath  the  base  of  one  of  the  segments, 
either  one,  two,  or  thi'ee  (the  latter  rarely)  lateral  tubercle-hke  projections 
are  formed,  originating  not  from  any  portion  of  the  segment  itself,  but  from 
an  extension  thereto  produced  between  the  inflated  base  and  the  sutural  line. 
When  more  than  one  is  formed,  they  are  usually  opposite, but  sometimes  side  by 
side.     A  gradual  elongation  of  the  projection  (or  projections)  then  takes  place, 
the  endochrome  in  the  immediate  neighbourhood  becoming  finely  granular, 
and  filling  what  has  now  become  an  elongate  lateral  tube  (or  tubes)  like  the 
finger  to  a  glove,  the  remainder  of  the  endochrome  being  as  yet  not  much 
altered,  and  the  terminal  clear  space  with  the  active  granules  being  still  in  situ. 
The  endochi'ome  within  the  lateral  tube  and  in  its  immediate  neighbourhood 
now  becomes  segmented  into  a  number  of  definitely  bounded  individuahzed 
portions,  which  presently  one  by  one  emerge  through  the  opened  apex  of  the 
lateral  tube,  and  become  associated  together  in  an  external  cluster.     The 
remaining  endoclirome  now  becomes  drawn  into  bands,  tm^ns  bro^vn,  and 
speedily  dies.     The  cluster  of  gonidia  at  the  apex  of  the  lateral  tube  now 
appear  to  have  become  encysted  each  within  its  own  special  coat ;  and  the 
green  contents  can  be  seen  twisting  backwards  and  forwards  within  the  con- 
fining membrane.     After  a  time  the  contents  emerge  each  from  its  cyst,  by 
rupturing  it,  and  slowly  swim  away  as  pyriform  or  ovate  ciliated  bodies, — 
as  we  apprehend,  veritable  zoospores.     The  author  was  entirely  unacquainted 
with  their  after-history ;  but  they  resemble  so  much,  in  their  appearance, 
growth,  and  mode  of  escape  from  the  parent-cell,  the  similar  bodies  in  Cla- 
dophora,  &c.,  which  are  indubitable  zoospores,  that  we  imagine  there  can  be 
little  question  as  to  the  nature  and  function  of  the  bodies  occurring  in  Doci- 
dium.    It  will  be  noticed  that  this  phenomenon  is  altogether  distinct  from, 
and  we  believe  in  no  way  to  be  confounded  with,  that  of  the  active  molecular 
movement  of  the  ultimate  granular  particles  of  the  endochrome  alluded  to  at 
pages  10  and  19  of  the  General  History, — a  circumstance  which,  indeed,  some- 
times accompanied  the  special  one  here  described,  in  Mr.  Archer's  specimens, 
but  sometimes  did  not,  and  which  is  one  of  very  general  occui'rence  under 
other  circumstances  and  in  other  cases,  and  has  probably  given  rise  to  the 
assumption,  often  made  in  our  EngHsh  books,  that  zoospores  occur  in  the 
Desmidiaceee.     Xor  is  the  production  of  zoospores  here  briefly  described  to 
be  in  any  way  confounded  M'ith  the  development  of  the  parasitic  plant  Pijtkium 
entophytum  (Pringsheim),  nor  of  any  species  of  Chytridium  (Braun).     The 


OF  THE  DESMIDIEJE.  717 

former,  indeed,  is  sometimes  met  with  in  various  Desmidians,  such  as  Cflos- 
terium  Lunula,  &c.,  as  well  as  other  Algae.  For  a  figure  of  this  curious 
parasitic  growth  attacking  Eremosphcera  viridis  (de  Bar j)  (^=  ChIoros2)hcera 
OliveH,  Henfi'ey,  the  former  name  having,  we  are  inclined  to  think,  the 
priority),  vide  '  Micrographic  Dictionarj^,'  2nd  ed.  pi.  xlv.  fig.  8.  There  can 
be  little  or  no  doubt  that  some  such  parasite  as  that  alluded  to  attacking 
a  species  of  Closterium  has  given  rise  to  Ehrenberg's  genus  Polysolenia, 
admitted  indeed  into  the  Desmidiaceae  by  Kiitzing,  but  which  we  here  cannot 
but  exclude. 

The  act  of  conjugation  and  formation  of  sporangia  is  not  uncommonly  to 
be  met  with  in  several  species.  The  after-development  of  the  sporangium 
seems  to  have  been  but  very  rarely  Ts^tnessed;  and  the  statement  made  in  the 
diagnosis  is  founded  on  the  account  given  by  M.  Hofmeister  (I.  c),  an  extract 
from  which  is  given  at  page  17;  also  on  the  very  similar  account  given  by 
M.  de  Bary,  '  Untersuchungen  liber  die  Famihe  der  Conjugaten : '  vide  pi.  6, 
shoAving  the  development  of  the  sporangium  of  Cosmarimn  Botrytis  (III.  48- 
54),  and  of  C.  MenegJiinii  (III.  55-60),  the  nimiber  of  sister-cells  formed 
within  the  sporangium  being  fewer  than  in  the  instances  cited  by  M.  Hof- 
meister. But  although,  in  the  cases  cited  by  M.  de  Bary,  the  cells  resulting 
from  the  segmentation  and  individualization  of  the  contents  of  the  sporangium 
are  eventually  of  a  Cosmarium-shape,  it  is,  however,  not  until  the  young- 
fronds  commence  self- division  in  the  ordinaiy  way,  that  the  fii-st-formed 
yoimg  segments  wholly  assume  the  special  characteristics  of  the  species  QII. 
52,  53,  54  t  58,  59,  60). 

The  nearest  affinities  of  this  family  seem  undoubtedly  to  be,  on  the  one 
hand  with  the  Diatomacese  (with  which  family,  indeed,  they  were  long 
associated),  and  on  the  other  with  the  Zygnemaceae  (Conjugatse) ;  while  to 
the  Palmellaceae  they  also  approach  through  the  genus  Penium,  connected 
with  CyUndrocystis  and  Mesotaenium  =  Palmogloea  {Kg.). 

It  will  be  at  once  seen  that  the  following  arrangement  of  the  species  is  for 
the  most  part  based  on  that  laid  down  in  Ralfs's  '  British  Desmidieae,'  1848, 
in  addition  to  which  the  following  works  have  been  consulted : — Kiitzing's 
*  Species  Algaiiim,'  1849 ;  Nageli's  '  Einzelliger  Algen/  1849 ;  Bailey's 
(Smithsonian  Contributions  to  Knowledge)  '  Microscopical  Observations  made 
in  South  Carolina,  &c.',  1850 ;  Brebisson's  '  Liste  des  Desmidiees  observees 
en  Basse  Normandie,'  1856 ;  de  Bary  {op.  cit.),  1858 ;  Papers  in  ^  Nat.  Hist. 
Review/  by  Rev.  R.  Y.  Dixon  and  by  Mr.  Archer,  1858-60.  The  first  and 
second  of  a  series  of  papers  by  Dr.  G.  C.  WaUich,  F.L.S.,  descriptive  of  some 
beautiful  and  interesting  species  of  Desmidiaceae  collected  by  him  in  Bengal, 
had  just  made  their  appearance  ('  Annals  Nat.  Hist.'  March  and  April,  I860) 
when  we  were  obliged  to  go  to  press.  It  has  seemed  to  us  more  advisable  to 
omit  any  description  of  those  species  than  to  introduce  a  few  only  without 
having  it  in  our  power  to  do  so  with  the  whole.  In  indicating  the  sources 
whence  we  have  been  able  to  derive  information  as  to  foreign  species,  it  is 
our  pleasing  duty  to  acknowledge  the  generous  and  courteous  assistance  of 
M.  de  Brebisson  in  affording  by  letter  the  requisite  information  which  that 
distinguished  and  experienced  observer  has  so  largely  at  his  disposal,  and 
without  which  our  own  acquaintance  with  the  Continental  forms  not  known 
in  this  country  would  have  been  far  more  circumscribed. 

The  following  genera  included  in  this  family  by  Kiitzing  in  'Species 
Algarum  '  are  here  excluded,  as  we  conceive  either  that  they  are  not  truly 
Desmidian,  or  the  unnecessary  splitting  up  of  older  genera : — 

Trochiscia,  excluded ;  Tetraedron,  excluded  ;  Pithiscus  =  Cosmarium  pyra- 
midatum  (Breb.) ;    Stauroceras  =  Closterium,  in  part ;  Polysolenia  (E.)  =  a 


7.18  SYSTEMATIC  HISTOKT  OF  THE  INFUSORIA. 

Closterium  attacked  by  a  parasitic  growth  (?) ;  Microtheca,  excluded  ;  Poly- 
edrium,  excluded ;  Zygoxanthium  =  Xanthidium,  in  part ;  Phycastmm,  Aste- 
roxanthium,  Stephanoxantliium,=Staurastrum ;  Grammatonema,  a  diatom; 
Beimhusmei  =  Didymo2:>r{um  Borreri;  Isthmosira  =  Sphaerozosma  ;  Eucampia, 
a  diatom  ;  Geminella,  excluded ;  Raphidium  =  Ankistrodesmus ;  Oocardium, 
excluded. 

The  other  genera  included  by  Kiitzing  are  placed  here  as  a  distinct  group, 
Pediastrese. 

Didymocladon  {Rolfs)  seems  not  distinguished  from  certain  Staurastra  by 
characteristics  sufficient  to  separate  it  from  them ;  we  have  therefore  imited 
them,  in  which  we  follow  Brebisson. 

As  to  the  new  or  altered  genera  proposed  by  Nageli  and  de  Baiy,  founded 
rather  on  the  mode  of  disposition  of  the  endochrome  than  on  the  external  form, 
although  we  do  not  venture  to  deny  its  probably  great  importance,  yet  it 
seems  to  us  that  the  characters  relied  on  are  in  many  instances  not  sufficiently 
constant  for  the  purpose,  as  well  as  that  several  of  the  known  Desmidian 
species  could  not  be  satisfactorily  or  indubitably  referred  to  the  particular 
genus  to  which,  judging  from  analogy,  they  ought  to  belong ;  neither,  indeed, 
does  it  seem,  so  far  as  we  can  judge,  that  those  writers  are  themselves  satisfied 
as  to  the  proper  place  of  certain  species,  nor  does  the  system,  as  yet,  appear 
quite  without  the  disadvantage  of  disassociating  kindred  forms.  We  believe 
we  are  fortified  in  the  opinion  we  here  endeavour  to  express  by  that  of  M.  de 
Brebisson.  The  genera  Cylindrocystis  and  Mesotsenium  are  here  omitted  from 
this  family,  as  their  claims  to  admission  scarcely  seem  as  yet  indubitable ; 
moreover,  there  seems  to  us  Httle  certainty  as  to  the  limitation  of  the  species 
hitherto  described  by  Kiitzing  and  others. 

If  we  have  omitted  some  of  the  species  described  by  the  various  authors 
before  cited,  it  is  from  a  conviction  that,  when  either  not  satisfied  as  to  their 
absolute  distinctness,  or  unfurnished  with  what  we  could  look  upon  as  suffi- 
ciently exact  details,  it  was  the  safest  course  we  could  pui'sue, — as  it  seemed 
to  us  better  to  leave  out  a  few  species,  than  to  insert  them  with  a  description 
which,  owing  most  likely  to  our  own  want  of  perception,  might  prove  insuf- 
ficient or  inaccurate.  On  the  other  hand,  some  may  think  we  have  admitted 
too  many  species,  and  that  certain  of  the  forms  hereafter  described  may  be 
but  "varieties"  of  whichever  may  be  assumed  as  the  typical  specific  form; 
but  in  this  conclusion  we  cannot  coincide,  as  we  are  disposed  to  believe  that 
the  species  hereafter  described  (with  possibly,  indeed,  a  few  rare  exceptions) 
are  quite  distinct,  and,  at  least  so  far  as  British  or  Irish  species  are  concerned, 
are  always  perfectly  distinguishable. 

An  ingenious  method  of  succinctly  expressing  by  means  of  symbols  the  ex- 
ternal characteristic  forms  of  the  genera  Tetrachastrum,  Micrasterias,  and 
Euastrum,  was  propounded  in  a  paper  by  Rev.  E.  Y.  Dixon,  read  to  Nat.  Hist. 
Soc.  Dub.,  3rd  June,  1859.  We  append  his  own  explanation,  as  the  best  that 
could  be  given  : — 

"  The  typical  mode  of  division  [in  the  genera  above  named]  (as  exemphfied 
in  Euastrum  pinnatum,  E.  ohlongum,  &c.)  appears  to  be  into  three  portions  or 
subdivisions, — the  first,  next  the  line  of  separation  of  the  segments,  extend- 
ing across  the  frond,  and  embracing  the  two  basal  lobes  ;  the  second  iucluding 
the  median  lobes  ;  and  the  third,  the  extreme  or  end  lobe.  This  last,  or  third 
subdivision,  is  the  most  constant.  The  two  former  are  frequently  represented 
by  a  mere  sinuosity  or  shallow  indentation  where  the  third  is  distinctly  deve- 
loped ;  but  we  never  find  the  fii'st  subdivision  distinct,  and  the  second  and 
third  imperfectly  separated.  The  whole  three,  indeed,  maybe  merely  marked 
by  slight  sinuosities,  as  in  Euastrum  cuneatum ;  but  if  any  one  is  separated,  it 


OF  THE  DESMIDIE^. 


719 


is  the  third.  And  this,  I  may  observe,  is  the  order  of  development  of  the  sub- 
divisions in  the  growing  segment  of  the  typical  Micrasterias  :  the  new  seg- 
ment is  first  hemispherical;  the  third  subdivision  is  then  developed;  and 
afterwards  the  first  and  second  are  separated. 

"  For  the  purposes  of  description  these  three  subdivisions  might  be  denoted 
by  the  letters  «,  h,  c,  and  their  partial  or  complete  development  marked  as 
follows : — When  the  subdivisions  are  distinctly  separated,  their  symbols  might 
be  separated  by  commas,  thus,  a,  h,  c ;  when  any  two  or  more  are  merely 
marked  by  a  sinuosity,  they  may  be  represented  thus,  a^^h  ;  and  if  there  is 
no  trace  of  separation,  thus,  ah ;  and  if,  at  the  same  time,  the  direction  of  the 
lines  separating  the  subdi\dsions  were  noted,  the  full  description  as  regards 
the  divisions  of  the  segments  would  be  given.     Thus —  [See  page  721.] 


CONSPECTUS  OF  THE  GENERA. 


/Joints  many  times 
longer  than 

broad  ;  neither 
constricted  nor 
with  lateral  teeth 
or  projections. 


-2  ,^ 


-2'Sd 


Joints  mostly 
broader  than 
long,  seldom 
slightly  longer 
than  broad;  more 
or  less  con- 
stricted, or  with 
lateral  teeth  or 
angles,  or  other- 
wise figured 


f^  Filament    not    at- 
tached   


Filament  attached. 


Filament  cylindri- 
cal or  subcylin- 
drical   


/^Joints  not  con- 
stricted    . . . 


s 


Joints  more  or 
less  deeply 
constricted . 


''Endochrome  arranged 

in  spiral  bands GtENIcularia. 

Endochrome  a  simple 
central  longitudinal 
contracted  band    . . .  Gonatozygon, 

Endochrome  a  single 
longitudinal  flatten- 
ed band Leptocystinema. 

^Joints  constricted  or 
with  a  projecting  an- 
nular rim  at  one  or 
both  ends  Hyalotheca. 

Joints  with  a  bidentate 
process  or  angle  at 
opposite  sides    Didymoprium. 

Filament  3-4-angu- 
lar  ;  joints  having 
the  external  margin 
plane  or  slightly  cre- 
nated,  united  to  each 
other  by  projections 
springing  from  the 
outer  portion  of  each 
extremity,  thus  pro- 
ducing intervening 
central  foramina  ...  Aptogonum. 
( Filament  3-4-angu- 
lar  or  compressed ; 
joints  either  closely 
united  by  a  thick- 
ened border  for  their 
entire  end-margin, 
or  by  projections 
producing  interven- 
ing central  foramina, 

as  in  last    Desaiidium. 

Filament  compressed; 
joints  united  to  each 
other  by  minute  tu- 
bercles or  gland- 
like processes    SriiiEROzosMA. 

Filament  compressed 
or  3-angular ;  joints 
without  intermedi- 
ate tubercles  or  pro- 

Spondylosium. 


720 


SYSTEMATIC  HISTOKY  OF  THE  INFUSOEIA. 


Frond  often  as 
broad  as  long, 
rarely,  if  ever,  as 
much  as  three 
times  longer  than 
broad.  Sporan- 
gia mostly  orbi- 
cular and  spi- 
nous, rarely  orbi- 
cular or  quadrate 
and  naked   


Fronds  deeply  con- 
stricted ;  seg- 
ments more  or 
less  deeply  lobed, 
or  if  merely  un- 
dulate or  taper- 
ing, the  ends 
acutely  notched.. 


^  Segments  3-lobed,  lateral 
lobes  attenuated,  their 
apices  entire  or  bifid. . .  Tetrachastrum. 

Segments  3-5-lobed,  la- 
teral lobes  expanded, 
incised,  their  external 
margins  dentate  or 
rarely  sinuate    Micrasterus. 

Segments  3-5-lobed,  or 
sometimes  only  late- 
rally emarginate  or  si- 
■{  nuate,  undulate  or 
tapering ;  lateral  lobes 
rounded,  entire,  or  si- 
nuately  emarginate ; 
end-lobe  mostly  cen- 
trally emarginate  or 
concave,  the  segments 
with  variously  disposed 
inflated  circular  promi- 
nences (the  two  latter 
characters  never  simid- 
taneously  absent*)  ...  Euastrum. 

Segments  not  lobed,  en- 
tire, mostly  rounded, 
rarely  undiilate  at  the 
margin,  ends  never 
emarginate,  sometimes 
with  a  solitary  central 
inflated  prominence  on 
each  front  surface  ; 
without  spines  or  pro- 


Fronds  distinctly, 
mostly  deeply, 
constricted ;  seg- 
ments mostly  en- 
tire, or  if  some- 
what undulate, 
the  ends  not 
notched    


COSMARIUM. 


Frond  mostly  many 
times,  rarely  less 
than  three  times, 
longer  than 

broad.  Sporangia 
smooth  {Penium 
annulatum  and 
SpirotcBnia  mus- 
cicola  are  some- 
times not  more 
than  twice  as 
long  as  broad)... 


f  Frond  dis- 
tinctly con- 
stricted at 
the  middle. 


Frond  either  not  at 
all  constricted,  or 
with  a  slight  and 
gradual  attenua- 
tion towards  the 
middle 


Segments  compressed, 
entire,  spinous,  with  a 
central  circular,  cylin- 
drical, or  conical  pro- 
jection on  both  front 
surfaces Xanthidium. 

Segments  compressed,  en- 
tire, either  with  two  or 
with  four  acute  teeth 
or  simple  or  geminate 
subulate  spines  placed 
on  the  external  angles 
or  prominences,  with- 
out a  central  projec- 
tion      Arthrodesmus. 

Segments  m  e.  v.  angular 
or  radiate Staurastrum. 


^ in- r  Ends  trilobed.  Triploceras. 

lated  at  the  \ 

base [  Ends  truncate.  Docidium. 

Segments  not 
inflated     at 

the  base   ...     Ends  notched.  Tetmemorus. 
/^  Frond  curved  or  arcuate, 

not  constricted Closterium. 

Frond  straight,  ends 
truncate  or  rounded, 
scarcely  or  not  at  all 

constricted     Penium. 

Frond  sti'aight  or  nearly 
80,  endochrome  spi- 
rally twisted Spirot^nia. 


y 


*  Euastrum  crenatim  (Kg.)  is  perhaps  an  exception. 


OF  THE  DESMIDIE.i:.  721 

[Pro msionally  included. ] 
Cells  elongate,  attenuated,  entire,  aggregated  into  faggot-like  bundles...  AxKisTRODESjrus. 
Cells  rounded,  compressed,  deeply  constricted,  stipitate    Cosmocladium. 


\)j  cr 

^b^c. 

a, 

h, 

c,  parallel. 

a, 

b, 

c,  subradial. 

a, 

b. 

c,  radial. 

a" 

-b, 

c,  parallel. 

ah 

»    C', 

parallel." 

"  Eiiastrum  cuneatum  would  be  represented  bj  a 
Eua  strum  piniiaium, 
Euastrum  oblongum, 
Micrasterias  denticulata, 
Euastrum  pectinatum, 
Tetrachastrum 

The  following  contractions  are  employed,  which  may  require  explanation : — 
f.  v.,  front  -snew ;  s.  v.,  side  view ;  e.  v.,  end  view ;  tr.  v.,  transverse  view ; 
e.  f.,  empty  frond;  L.,  length,  B.,  breadth,  of  frond.  The  measiurements  are 
expressed  in  so  many  fractions  of  inch  by  the  use  of  two  acute  marks,  thus, 
L.  1-598"  =  length  of  frond  5-^th  of  an  inch.  In  most  of  the  foreign  species 
we  are  without  the  data  to  give  measurements.  G.B.,  Great  Britain  ;  I.,  Ire- 
land ;  F.,  France ;  G.,  Germany ;  U.S.A.,  United  States  of  America,  refer- 
ring to  the  record  of  the  occuiTence  of  the  species  in  those  countries.  It  is 
behoved  that  even  this  rough  attempt  at  an  indication  of  the  distribution  of 
these  organisms  may  not  be  altogether  without  its  use.  Doubtless  many  occur, 
and  perhaps  different  forms,  in  other  countries  of  Europe ;  and  information 
is  much  wanted  in  this  respect  as  to  other  parts  of  the  world. 

Where  a  species  occurs  under  another  name  in  the  works  above  cited,  we 
have,  as  far  as  possible,  given  the  s}Tionym,  but  should  it  occur  there  under 
the  same  name,  it  is  not  repeated. 

The  characters  printed  in  italics  are  such  as  immediately  distinguish  each 
species  from  its  nearest  aUies,  and,  the  genus  being  known,  are  probably 
those  which  should  be  first  consulted ;  but  it  is  always  requisite  to  peruse  the 
whole  of  the  characters  applicable  to  each  species  and  genus,  with  a  Wew  to 
render  the  identification  accurate. 


A.  Plant  an  elongated  jointed  filament.     Sporangia  orbicidur,  smooth. 
1.  Joints  many  times  longer  than  broad. 

Genus  GENICULARIA  (De  Bary). — Filament  cylindrical ;  joints  elongate, 
cylindrical,  without  a  constriction  or  inflation,  ends  truncate  ;  endochrome 
arranged  in  two  or  three  spiral  hands  upon  the  cell-waU,  sometimes  irregular. 
Joints  previous  to  conjugation  disunited,  and  bent  during  the  process ;  spo- 
rangium placed  between  the  empty  conjugated  joints. 

Gexicularia  sjjirotcema  (De  Bary).  rangiiim  orbicular,  smooth,  placed  be- 
—  Joints  ten  or  twenty  times  as  long  '\  tween  the  conjugating  joints,  which  are 


as  broad,  very  slightly  enlarged  towards 
their  ends,  on  the  outer  smface  rough 
with  minute  scattered  gi-anules.      Spo- 


bent  into  a  knee-shape,  with  which  it 
remains  for  some  time  in  connexion. 
"B.l-130"'-1-100.""'   (m.  3.)     G. 


Genus  GOiN'ATOZYGOTs''  (De  Bary).— Filament  cylindrical ;  joints  elon- 
gate, slender,  cyhndiical  or  narrow-fusiform,  mthout  a  constriction  or  in- 
flation, ends  truncate  ;  endochrome  a  single,  central,  longitudinal,  undtdatory, 
contracted  hand.  Joints  pre^sious  to  conjugation  disunited,  and  during  the 
process  bent  into  a  knee  shape  ;  sporangium  as  last. 

GoNATOZYGON  i?r///s?V  (De  Bary)- — I  what  dilated,  ten  to  twenty  times  as 
Joints  ci/lifidrical  with  the  ends  some-  |  lonsr  as  broad,  rough  on  the  surface  v.ath 

a  A 


722 


SYSTEMATIC  niSTORY  OF  THE  INFUSORIA. 


numerous  minute  scattered  granules 
endochrome  sometimes  bitid  at  the  ex 
tremities,  usually  with  a  pale  space  at 
the  centre,  and  with  a  longitudinal  me- 
dian series  of  lighter-coloured  dense  cor- 
puscles. Sporangium  same  as  precedino- 
species.  (iii.l,2.)  L.  1-100" ;  B.l-2:350'\ 
JJocidium  aHperum  (Ralfs)  ;  Leptocijsti- 
nema  aspenon  (Archer).     G.B.,  I.,  F.,  G. 

G.  Brehissonii  (De  B.).  —  Joints  nar-  \  varjdng  in  length. 


;  I  row-fmiform,  subcapitate  at  ends,  loosely 
j  united,  often  single,  rough  on  the  surface 
j  with  minute  scattered  gi*anules ;  endo- 
chrome usually  with  a  pale  space  at  the 
.  centre,  and  a  median  series  of  corpuscles. 
Sporangium    as    preceding.      Dociduim 
'  asperum  (Breb.)  ;  Lep.  Fort  it  (Archer). 
L.  1-200"  to  1-105";  B.    1-3500".     L, 
F.,   G.      /3  much   smaller,   and  joints 


Genus  LEPTOCYSTIXEMA  (Archer).— Filament  attached,  cyHndrical ; 
joints  elongate,  cylindrical,  slender,  linear,  without  a  constriction  or  inflation, 
ends  truncate  ;  endochrome  a  longitudinal  Jlattened  hand.  (No  e\ident  gela- 
tinous sheath.) 

A  genus  under  the  above  name  was  founded  by  Mr.  W.  Archer  (Nat.  Hist. 
Rev.  vol.  V.  p.  250)  for  the  reception  of  the  single  species  now  here  included, 
as  well  as  the  two  species  of  Gonatozygon  (De  B.),  not  being,  however,  then 
aware  that  De  Bary  had  pre\iously  established  the  latter  genus  in  '  Hedwigia.' 
However,  as  the  reproductive  condition  of  Lep.  Kinahani  (Archer)  is  yet 
unlmown,  we  deem  it  more  acMsable  to  allow  that  species  to  remain  under 
its  original  name,  and,  for  the  present  at  least,  to  retain  the  genus,  distin- 
guishing it  here  from  Gonatozygon  by  the  filaments  being  attached  (a  singular 
circumstance  in  Desmidiacese),  and  the  endochrome  a  flattened  band.  The 
species  is  very  distinct  indeed  from  the  two  preceding. 


Leptocystestema  Kinahani  (Archer). 
—  Filament  2  to  3  inches  long,  often 
breaking  up  into  separate  joints;  joints 
20  to  40  times  as  long  as  broad,  linear, 
smooth  ;  endochrome  in  its  broader  dia- 
meter filling  the  entire  width  of  the 
joint — in  the  narrower,  not  more  than 
-one-third,  occup}dng  the  centre  of  the 
joint,  and  at    the   central    pale    space 


curved  towards  the  ceU-wall,  and  hav- 
ing imbedded  within  it  a  longitudinal 
median  series  of  globular,  light-coloured, 
dense  corpuscles  (one  occuppng  the 
centre  of  the  pale  space),  retracted  at 
each  end  of  the  joint,  leaving  a  clear 
space  in  which  are  active  granules. 
Sporangium  unknown.  L.  1-200"  to 
1-50";  B.  1-1900".    (m.  4.)     I. 


2.  Joints  mostly  broader  than  long,  very  seldom  slightly  longer  than  broad. 

Genus  HYALOTHECA  (Ehr.). — Filament  ci/Iindrical,  very  gelatinous; 
joints  having  either  a  slight  constriction,  which  produces  a  crenate  appearance, 
or  a  grooved  rim  at  one  or  both  ends,  Avhich  forms  a  bifid  projection  at  each 
side ;  end  view  circular ;  endochrome  radiate. 

Hyalotheca  dissiliens  (Br(5b.). — Fila- 
ment fragile,  crenate ;  joints  usually 
broader  than  long,  with  a  shallow  groove 
round  each,  dividing  the  endochrome 
into  two  portions.  Sporangium  globular, 
smooth,  placed  within  the  persistent 
connecting  tube  formed  by  the  mutual 
fusion  of  a  fresh  extension  from,  and 
produced  between,  the  sides  opposed  to 
each  other  of  the  conjugating  pairs  of 
joints,  the  filament  having  previously 
broken  up  into  single  joints,  (ii.  32  &  35). 
L.  1-2105"  to  1-1351";  B.  1-1308"  to 
1-833".  =  Conferva  dissiliens  (Smith), 
Glaoprium  dissiliens  (Berk.,  Hass.),  Hya- 
lotheca mucosa  (Kg.).  G.B.,  I.,  F.,  G., 
U.S.A. 


H.  mucosa  (Ehr.). — Filament  scarcely 
fragile,  mucous  sheath  very  broad;  joints 
about  as  broad  as  long,  not  constricted, 
hut  having  at  one  of  the  ends  a  mimite 
hidentate  projection  on  each  margin,  the 
adjoining  end  of  the  next  joint  being 
similar,  these  projections  being  produced 
bv  an  annular  grooved  rim.  L.  1-1250" 
to  1-6G0';  B.  1-1250"  to  1-1111". 
=  Conferva  w«/cos«(Mert.,Hook.,Harv.), 
Gloeoprium  mucoswn  (Hass.),  H.  Ralfsii 
(Kg.).     G.B.,I.,F. 

H.  ?  duhia  (Kg.). — Filament  without  a 
mucous  sheath  (?) ;  joints  rather  broader 
than  long,  with  two  puncta  near  each 
margin.     G. 


OF  THE  DESMIDIE^. 


'23 


Genus  DIDYMOPRIUM  (Kg.). — Filament  gelatinous,  cylindrical,  regu- 
larly twisted;  joints  ^\dth  a  bidentate  process  or  angle  at  each  side ;  end  view 
circular,  or  broadly  elliptic,  with  two  opposite  projections  formed  by  the 
ansrles :  endochrome  radiate. 


Dn)yiioPRiUMG^/-ei-///iV(Kg.). — Sheath 
distinct;  joints  broader  than  long,  ivith 
a  thickened  border  at  their  junction ;  angles 
bidentate ;  teeth  angular ;  transverse  view 
broadly  elliptic.  Sporangium  orbicular, 
formed  within  one  of  the  two  conju- 
gating joints,  the  endochrome  passing 
over  from  one  by  a  narrow  connecting 
tube  produced  between  the  otherwise 
but  little  altered  broken-up  single  joints. 
L.  1-464";  B.  1-^70".  =I)esmidium  cy- 
lindricmn  (auct.),  Arthrodesmus  ?  cyl. 
(Ehr.),  Desmidium  comjiressuni  (Corda), 
D.  Grevillii  (De  B.).  G.B.,  I.,  R,  G., 
Prussia,  U.S.A. 


D.  Borreri  (Ralfs). — Joints  inflated, 
barrel-shaped,  longer  than  broad,  icithout 
a  thickened  border  at  their  junction ;  angles 
bicrenate,  crenatures  rounded ;  transverse 
vieiv  circidar.  Sporangium  elliptic,  fomied 
within  the  (for  some  time)  persistent 
extensions  from  the  conjugating  joints, 
which  do  not  previously  break  up  into 
single  joints,  but  couple,  still  united  in 
the  filament,  in  a  confused  or  zigzag 
manner,  some  of  the  joints  remaining 
unchanged,  (ii.  38,  39.)  L.  1-939" ; 
B.  1-1030".  =  Bambusina  Brebissonii 
(Kg.,  Breb.).     G.B.,  L,  F.,  G.,  U.S.A. 


Genus  APTOGONUM  (Ralfs). — Filament  S-4-angular ;  joints  not  con- 
stiicted,  plane  or  crenated  at  the  lateral  margins,  united  only  at  the  outer 
portions  of  each  of  their  end  margins  by  mutual  projections,  thus  producing 
intervening  central  oval  foramina. 

mina  broadly  oval  j   in  e.  v.  triangular. 


Aptoggntjm  Baileyi  (Ralfs). — Joints 
in  f  V.  quadrangular,  about  as  broad  as 
long,  their  lateral  margins  plane]  fora- 


angles  somewhat  roimded.  (in.  5,  e.v.  6.) 

U.S.A. 


Genus  DESMIDIUM  (Ag.). —  Filament  3-4-angular  or  compressed,  regu- 
larly twisted ;  joints  bidentate  or  bicrenate  at  the  angles  or  lateral  margins, 
and  either  closely  imited  throughout  the  whole  of  their  end  margins  by  a 
thickened  border,  or  only  at  the  outer  portion  of  each  by  mutual  projections, 
and  thus  producing  intervening  central  oval  foramina. 

DESMinior  aptogonum  (Breb.).  —  ,  G.B.,  I.,  F.,  G.,  Italy,  Sweden,  U.S.A. 
Joints  in  f.  v.  quadrangular,  broader  [  D.  quadrangulatiim  (Ralfs). — Filament 
than  long,  with  two  rounded  crenatures  quadrangular,  varying  in  breadth  from 
on  each  lateral  margin,  imited  at  the  its  twisting,  having  two  longitudinal 
outer  portion  only  of  each  end  margin  \  waved  lines;  joints  in  f  v.  broader  than 
by  mutual  projections,  thus  producing  \  long,  with  two  someivhat  rounded  cre- 
intervening  central  oval  faramina.     G.B.,  !  natures  on  each  lateral  margin,  imited  by 


F.,  G.,  U.S.A.  a.  Filament  triangular, 
regularly  tudsted,  crenatures  roimded. 
L.  1-1490";  B.  1-1000".  (ni.7,  e.v.  8.) 
i3,  filament  compressed,  crenatures  shal- 
lower, and  slightly  angular.  L.  1-1295"; B. 
1-925" .  =  Aptogomwi  Desmidium  (Ralfs). 
D.  Swartzii  (Ag.).  —  Filament  trian- 
gular, equal,  vtdth  a  single  longitudinal 
waved   dark  line  formed  bv  the  third 


the  whole  of  their  end  margins ;  e. 
quadrangular  ;  endochrome  fom--raved. 
(II.  37,  40.)  L.  1-1244";  B.  1-603"  to 
1-455".  =  Z>.  quadranqulare  (Ko;.),  G.B., 
F.,G.,  U.S.A. 

D.  undulatum  (Corda). — Filament  tri- 
angular-, joints  in  f  v.  with  a  slight 
central  notch  at  each  side,  and/o?/7-  broad 


angle;  joints  in  fi-ont  view  somewhat  by  the  whole  of  their  end  margins, 
quadi-angiilar,  broader  than  long,  with  |  D.  didymum  (Corda). — Filament  tri- 
two  slightly  angular  crenatmes  on  each  !  angular;  joints  in  f  v.  bidentate,  broader 
lateral  margin,  imited  at  the  whole  of  than  long,  imited  by  the  whole  of  their 
their  end  margins  by  a  thickened  border ;  I  end  margins ;  e.  v.  triangidar ;  angles 
end  -view  triangular ;  endochrome  three-  I  acutely  hi/id.  =  Desmidiuin  biiidum 
rayed.  L.  1-2000"  to  1-1666";  B.  1-633".  |  (Menegh.).     G.,  Italy. 

Genus  SPH.^ROZOSMA  (Corda). — Filament  compressed;  joints  deeply 
divided  on  each  side,  thus  forming  two  segments,  and  giving  a  pinnatifid 

:^  A  2 


'24 


SYSTEMATIC  HISTORY  OF  TIIE  IXFUSORIA. 


appearance  to  the  filament,  united  to  each  other  by  minute  tubercles  or  gland 
lihe  processes. 

Sph^rozosma  rertehratum  (Ralfs) 


Joints  as  long  as  broad,  constriction  deep, 
aeute ;  segments  reniform,  giand-like 
processes  oblique,  solifari/  at  the  centre  of 
each  margin.  A  gelatinous  sheatli  evi- 
dent. Sporangium  spherical,  smooth, 
placed  between  the  empty  segments,  the 
lilament  previously  to  conjugation  break- 
ing up  into  single  joints.  L.  1-1429"; 
B.  1-909"  to  1-666".  (i.  1^-17. )  =  Sph. 
elegans  (Corda,  Hass.),  OdonteUa  loii- 
dentata  (Elir.),  Isthniia  vertebrata 
(Menegh.),  Isthmosira  vert.  (Kg.).  G.B., 
I.,  F.,  G.,  Italy,  U.S.A. 

S.  excavation  (Ralfs).  —  Joints  longer 
than  broad,  subquadrate,  very  minute; 
constriction  a  deep  rounded  sinus  on 
both  sides,  and  ftvo  sessile  f/land-like  pro- 
cesses on  each  mare/ in  at  their  junction; 

Genus  SPONDYLOSIUM  (Breb.)- 
joints  deeply  divideel  on  each  side,  thus 
pinnatifid  appearance  to  the  filament, 
processes. 

STO'N'DY'LOBiV'Msto7nato7norpha7n('BY.). 
—  Joints  about  one-third  broader  than 
long,  constriction  deep,  segments  reni- 
form, ends  brocully  rounded;  no  sheath. 
' z=  Isthmia  stomatomorpha  (Menegh.).  F. 

S.  pulchrum  (Bail.  sp.). — Joints  twdce 
as  broad  as  long,  constriction  not  deep, 
acute,  segments  elliptic ;  junction  margins 
^t\i{\o[h.i,  forming  short  connecting  bands  ; 
gelatinous  sheath  wide.  =  Sphcerozosma 
pulchrum  (Bail.).     U.S.A. 

S.  imlehellum  (iVrcher).  —  Filament 
minute,  fragile ;  joints  about  as  broad  as 
long,  sharply  incised ;  segments  laterally 
infiated  ett  the  base,  thus  giving  a  pouting 
appearance  to  the  joint,  mtr rowing  to 
the  ends,  which  are  streiight,  with  square 
angles ;  endochrome  containing  in  each 
segment  a  single,  central,  lighter- 
colom-ed,  globular  corpuscle.  No  evi- 
dent   gelatinous    sheath.      L.  1-2330"  ; 


angles  sometimes  with  three  very  minute 
teeth ;  no  evident  gelatinous  sheath. 
Sporangium  elliptic,  placed  between  the 
empty  joints,  the  tilament  previously 
breaking  up.  L.  1-2575";  B.  1-3050". 
=  Isthmosira  excavata  (Kg.).  G.B.,  I., 
F.,  U.S.A. 

S.^liforme  (Ehr.). — Joints  about  as 
long  as  broad ;  constriction  acute ;  seg- 
ments elliptic,  and  united  by  double 
slender  jyrocesses  ivhich  include  a  quadrate 
foreimen  between  each  pair.  =  Isthmosira 
JUiformis  (Kg.).     G. 

S.  lamelliferum  (Corda). — Joints  about 
one-third  laroader  than  long,  constriction 
deep,  slightly  rounded  within ;  segments 
'ed,  reniform ;  connecting  processes 


"  flattened, 
sheath.     G. 


colomless ;    a    gelatinous 


-Filament  compressed  or  ^-angular  ; 
forming  two  segments,  and  giving  a 
and  without  intermediate  tubercles  or 

B.  1-2330".   (m.  10.)     I. 

S.  dejn-essum  (Breb.). — Joints  some- 
what broader  than  long,  suhquadrate, 
constriction  a  rounded  sinus,  angles 
rounded,  ends  straight,  furnished  at  end 
margin  on  upper  surface  with  three 
rounded  protuberances ;  "  no  sheath." 
(III.  9.)     F. 

S.  serratum  (Bailey,  sp.).  —  Joints 
broader  than  long,  constriction  a  trian- 
gular notch ;  segments  foiining  lateral 
triangular  acute  p)rojeetions,  thus  giving 
a  serrated  outline  to  the  filament ;  junc- 
tion margins  straight.  =  Sphcerozosma 
serratum  (Bail.).     U.S.A. 

S.  secedens  (De  Bary,  sp.). — Filament 
very  fragile,  joints  as  long  as  broad,  con- 
striction a  shallow  rounded  sinus  ;  seg- 
ments subelliptic,  ends  concave ;  no  gela- 
tinous sheath.  L.  1-287"'.  =  Sphcerozosma 
secedens  (De  Bary).     G. 


B.  Fronds  simple,  free,  owing  to  complete  transverse  division. 
1.  Fronds  distinctly  constricted  at  the  middle,  never  as  much  as  three  times 
longer  than  broad.     Sporangia  mostly  spherical  and  spinous  or  tubercu- 
lated,  or  very  rarely  spherical  or  quadrate  and  naked. 

Genus  TETRACHASTRUM  (Dixon).  —  Frond  compressed,  deeply  con- 
stricted into  two  3-lobed  segments ;  lateral  lobes  projecting  horizontally,  or 
sometimes  divergent,  broadest  at  their  base  and  simply  atteiiuated  outwards ; 
end  lobe  laterally  expanded  into  a  horizontal  attenuated  projection  on  each 
side,  subtending  the  lateral  lobes  ;  central  constriction  a  gradually  widening 
incision  {ab,  c,  vide  supra). 


OF  THE  DESMIDIE.E. 


725 


T.      Amei'icanum     (nobis).  —  Frond 

broader  than  long,  suborbicular,  pinna- 

tifid;    lateral  lobes  separated  from  the 

terminal  by  a  deep  acute  incision,  hori- 

j  zontal,  conical,  tapering,  their  extremities 

i  bidentate ;  end  lobe  short,  its  lateral  pro- 

!  jections  long,  tapering,  bidentate  at  their 

j  extremities,  as  broad  and  long  as  the  lateral 

I  lobes ',  ends  broadly  rounded.  =  Micras- 

j  terias  incisa  (Kiitz.),  Bailey,  in   ^Micr. 

I  Obs.  in  S.  Carolina,'  &c.,  but  surely  not 

j  that  species ;  we  are  therefore  obliged  to 

place    it    here    under   another   specific 

I  name. 

I      T.  pinnaiijiduni  (Dixon). — Frond  ra- 

j  ther  broader  than  long,  plane,  pinnatifid ; 

I  lateral  lobes  separated  from  the  terminal 

I  by  an  equal  subacute  incision,  triangular, 

subcouical,  horizontal,  their  extremities 

bidentate ;    end   lobe    short,  its    lateral 

projections  transverse,  short,  bidentate 

at  the  extremities,  ends  straight  (colour 

pale).     L.  1-440";  B.  1-392''.  =  3//c;-as- 

terias  pinnatijida  (Ealfs,  Breb.)  ;   Euas- 

truin  pinnatifiduni  (Kg.).     G.B.,'F.,  G., 

U.S.A. 

T.  didymacanthum  (Nag.  sp.). — Frond 
about  as  broad  as  long,  pinnatifid ;  late- 
ral lobes  separated  from  the  temiinal  by 
a  icide  rounded  sinus,  their  lower  margin 
convex,  in  apposition  with  those  of  the 
opposite  segment  for  a  portion  of  their 
length,  then  slightly  divergent,  their 
upper  margin  nearly  straight,  horizontal, 
their  extremities  bidentate ;  end  lobe 
long,  united  to  the  basal  portion  by  a 
naiTow  neck,  its  lateral  projections  short, 
their  extremities  bidentate,  ends  slightly 
convex.  L.  1-40'" ;  B.  1-40"'.  =  Euas- 
t?'um  didymacanthum  (Nag.).     G. 

T.  quadratum  (Bail.  sp.).  —  Frond 
broader  than  long,  pimiatifid,  quadran- 
gular; lateral  lobes  separated  from  the 
tenninal  by  a  wide  rounded  sinus,  some- 
what injiated  at  their  base,  elongate, 
slightly  divergent  from  those  of  the 
opposite  segment,  their  produced  extre- 
mities slender,  bidentate ;  end  lobe  nar- 
row, produced,  its  lateral  projections 
transverse,  elongate,  slender,  bidentate 
at  the  extremities;  ends  vdi\\  a  slight 
central  conca\dty.  =  3Iic.  quadrata  (Bail.), 
U.S.A. 


*  Extremities  of  lobes  entire,  mucronate 
or  acute. 
Tetrachastrum  arcuatum  (Bailey, 
sp.). — Frond  rather  broader  than  long, 
pinnatifid,  quadrangular  ;  lateral  lobes 
long,  slender,  arcuate,  tapering,  divergent 
from  those  of  the  opposite  seginent,  their 
extremities  acute ;  tenninal  lobe  narrow, 
produced,  its  lateral  projections  uhruptly 
transverse,  slender,  attenuated,  acute ; 
ends    slightly   concave   at  the    centre. 

=  Micrasterias  arcuata  (Bail.).  U.S.A. 
T.  expansutn  (Bailey,  sp.).  —  Frond 
about  as  broad  as  long,  somewhat  stel- 
late ;  lateral  lobes  long,  slender,  straight, 
conical,  divergent  from  those  of  the  op- 
posite segment,  their  extremities  acute ; 
terminal  lobe  narrow,  produced,  its  la- 
teral proj  ections  somewhat  divergent,  short, 
quickly  tapering,  acute;  ends  concave. 
=  3Iicr.  expansa  (Bail.).     U.S.A. 

T.  mucronatum  (Dixon).  —  Frond 
longer  than  broad,  subelliptic ;  lateral 
lobes  very  broad,  straight  on  the  margin 
forming  the  base  of  the  segment,  tnrgid 
on  the  upper  margin,  their  extremities 
rounded,  fm-nished  on  the  margin  with 
one,  two,  or  three  minute  mucro-like  spifies, 
one  always  at  the  exti'emity  or  basal 
angle  of  the  segment,  others,  when  pre- 
sent, in-egularly  placed  on  the  upper 
margin ;  terminal  lobe  short,  very  broad, 
its  lateral  projections  short,  stout, 
quickly  tapering,  somewhat  incmwed  at 
extremities,  which  are  mucronate  ;  ends 
rounded,  with  a  very  shallow  inconspi- 
cuous centi'al  concavity;  tr.  v.  broadly 
elliptic;  e.  f.  pimctate.  L,  1-167";  B. 
1-235".     I. 

2  *  Extremities  of  the  lobes  bidentate. 

T.  oscitans  (Dixon). — Frond  about  as 
broad  as  long,  pinnatifid;  lateral  lobes 
separated  from  the  terminal  by  a  rounded 
sinus,  horizontal,  conical,  their  extremities 
bidentate ;  end  lobe  short,  broad,  its 
lateral  projections  short,  conical,  usually 
bidentate,  narrower  and  shorter  than  the 
lateral  lobes ;  ends  convex  at  the  centre  ; 
tr.  V.  fusiform,  e.  f.  punctate.  L.  1-256" ; 
B.  1-211".  (II.  28,  '^).=Euastrum 
holocystis  (Kg.);  Holocystis  oscitans 
(Hass.) :  Micrasterias  oscitans  (Ralfs). 
G.B.,  I.,  F.,  U.S.A. 

Genus  MICRASTEEIAS  (Ag.). — Frond  mostly  lenticular,  as  long  as  or 
slightly  longer  than  broad,  deeply  constricted  into  two  lobed  segments ;  seg- 
ments usually  semiorbicular,  5-  or  sometimes  3-lobed ;  lobes  incised  or 
divided,  mostly  radiant,  narrower  at  the  base  and  ividening  upivards,  their 
ultimate  subdivisions  spreading,  dentate  or  minutehj  spined,  or  rarely  only 
sinuate  at  the  outer  margin  ;  central  constriction  usually  linear. 


726 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


*  Tlie  subdivisions  of  the  lobes  spreading/ 
in  a  ijlane  at  right  angles  to  that  of  the 
frond,    (a,  h,  c.) 

MiCEASTERiAS  muricata  (Ralfs).  — 
Frond  CLiiadrangiilar ;  segments  sub-5- 
lobed,  lobes  opposite ;  basal  lobes  tripar- 
tite, middle  lobes  bipartite;  end  lobe 
exserted  and  laterally  divergent,  its 
lateral  extensions  bipaiiite ;  all  tlie  sub- 
divisions of  all  the  lobes  divergent  and 
disjjosed  in  a  j^lfne  at  right  angles  to  the 
plane  of  the  frond,  their  exti'emities  ter- 
minating in  three  or  four  projecting 
points;  the  intervals  between  the  lobes 
deep  rounded  sinuations ;  ends  straight, 
entlve.  =JEifastrutn  muricatum  (Bailey). 
U.S.A. 

2  *  Tlie  subdivisions  of  the  lobes  ^reading 
in  the  same  pla?ie  as  the  frond. 

t  Frond  subelliptic ;  segments  3-  or  sub- 
5-lobed,  lobes  spreading,  the  intervals 
between  the  lobes  being  wide  ;  lateral 
lobe^  bipartite,  their  subdivisions  di- 
vergent, end  lobe  exserted  and  laterally 
divergent.    (a^6,  c.) 

M.  Baileyi  (Ralfs). — Frond  granulated 
all  over  \  segments  3-lobed  ;  lateral  lobes 
deeply  bipartite,  subdivisions  slender, 
their  exti-emities  bidentate,  the  lower 
subdivisions  horizontal,  approximate  to 
those  of  the  opposite  segment,  the  upper 
divergent;  end  lobe  naiTow  below,  ex- 
serted, transversely  expanded,  its  lateral 
extremities  truncate;  ends  concave, 
U.S.A. 

M.  ringens  (Bailey).  —  Frond  some- 
what coarsely  granulated  at  the  7nargin ; 
segments  3-iobed ;  lateral  lobes  some- 
what broadly  bipartite,  stout,  divergent 
from  those  of  the  opposite  seginent, 
their  subdivisions  ha^-ing  the  extremities 
obscm-ely  bidentate;  end  lobe  nan'ow 
below,  exserted,  transversely  expanded, 
its  lateral  extremities  obtuse  ;  ends  con- 
cave.    U.S.A. 

M.  furcata  (Ag.).  —  Frond  smooth  ; 
segments  sub-5-lobed ;  basal  and  middle 
lobes  bifid,  their  subdivisions  slender, 
linear,  divergent,  and  forked  at  the  apex, 
bifm'cation  usually  incurved',  end  lobe 
exserted,  with  a  rounded  sinus  between 
the  considerably  produced  divergent  ex- 
tensions from  the  angles,  which  are  ulti- 
mately forked,  their  bifm*cations  in- 
curved. L.  1-135";  B.  1-156".  =  31. 
radiata  (Hass.),  31.  3Ielitemis  /3  gracilis 
(Kg.).     G.B.,  U.S.A. 

M.  Crux-Melitcnsis  (Ralfs).  —  Frond 
smooth ;    segments    sub-5-lobed ;    basal 


and  middle  lobes  bifid,  subdivisions 
short,  stout,  and  bidentate  at  the  apex ; 
end  lobe  exserted,  with  a  roimded  sinus 
bet^'een  the  produced  divergent  exten- 
sions from  the  angles,  which  are  idti- 
mately  bidentate.  L.  1-206"  ;  B.  1-221". 
(i.  22).  =  Euastrum  Cnix-llelitensis 
(Ehr.)  ;  31.  3Ielitensis  (Menegh.).  G.  B., 
F.,  a,  Italy,  U.S.A. 

2t  Frond  angular-elliptic,  subquadi-ate 
or  suborbicular ;  segments  3-lobed; 
lobes  spreading,  the  intervals  between 
the  lobes  being  usually  wide ;  lateral 
lobes  either  bipartite  and  inciso-den- 
tate  or  tnmcate  on  outer  margin  ; 
end  lobe  mostly  exserted,  divergent. 
{a--b,c.) 

M.  Americana  (Ralfs). — Frond  angu- 
lar elliptic,  more  or  less  punctate ;  seg- 
ments 3-lobed;  lateral  lobes  broad, 
cuneate,  their  margins  concave,  inciso- 
serrate;  end  lobe  broad,  cuneate,  and 
exserted,  bipartite  at  the  angles,  the 
subdivisions  naiTOw,  and  minutely  den- 
tate at  the  extremities;  end  concave. 
L.  1-204";  B.  1-254".  (ii.  44,  bad).= 
Euastrum  Americanum  (Ehr.).  G.  B., 
I.,  F.,  U.S.A.  /3,  margins  waved  rather 
than  dentate. 

M.  foliacea  (Bailey). — Frond  sub- 
quadrate,  smooth  ;  segments  3-lobed ; 
lateral  lobes  deeply  bipartite,  inciso- 
dentate,  their  margins  extending  to  an 
equal  distance  from  the  middle  line  of 
the  frond,  with  a  short  rounded  tootli- 
like  projection  next  the  end  lobe ;  end  lobe 
narrow,  somewhat  dilated  above,  angles 
emarginate  ;  ends  concave.     U.S.A. 

M.  incisa  (Kg.), — Frond  about  as 
broad  as  long,  suborbicular ;  lateral  lobes 
horizontal,  sides  parallel,  abruptly  trun- 
cate, tcith  a  tooth  at  each  angle  ;  end  lobe 
short,  very  broadly  cimeate,  entire,  its 
angles  acute.  =  Euastrum  Crux-3Ielitensis 
(Ehr,).     G.,  F.,  U.S.A.  ?^ 

M.  decemdentatutn  (Xag.).  —  Frond 
about  as  broad  as  long,  suborbicular; 
segments  3-lobed;  lateral  lobes  hori- 
zontal, side  subparallel,  obscurely  bipar- 
tite, their  subdivisions  acutely  bidentate; 
end  lobe  broadly  cuneate,  entire,  angles 
acute;  ends  roimded.  L.  1-55"';  B. 
155"'.  =  31.  Neodamemis  (Braun) ;  31. 
Itzigsohnii  (Breb.).     F.,  G. 

3t  Frond  cu'cular;  segments  5-lobed; 
lobes  approximate,  the  intervals  be- 
tween the  lobes  being  linear  or  very 
deep  and  acute  incisions ;  basal  and 
middle   lobes  dichotomouslv  divided 


OF  THE  DESMIDIE.E. 


T2\ 


or  deeply  incised;  end  lobe  narrow, 
seldom  and  but  very  slightly  exserted. 
{a,  h,  c.) 

M.  Torreyi  (Bail.). — Frond  smooth; 
segments  5-lobed;  basal  lobes  bifid, 
middle  lobes  trifid,  the  subdivisions 
neai'est  the  opposite  segments  and  those 
nearest  the  terminal  lobe  bideidafe  at  the 
apex ;  tlie  intennediate  three  terminat- 
ing in  acute  points  ;  all  somewhat  injlated 
and  tapering ;  tenninal  lobe  narrow,  not 
exserted,  spreading  at  the  angles  into 
divergent  tapering  points  ;  ends  slightly 
emarginate.     U.S.A. 

M.  denticidata  (Breb.). — Frond  orbicu- 
lar, smooth ;  segments  o-lobed;  basal  and 
middle  lobes  twice  dichotomous;  idti- 
mate  subdivisions  truncato- emarginate, 
with  rounded  angles ;  end  lobe  simply 
thrice  emarginate.  Sporangium  orbicu- 
lar, beset  with  scattered  stout  elongate 
spines,  at  first  simple  and  obtuse,  after- 
wards forked  or  tiifid,  their  divisions 
finally  again  branched  and  recurved.  L. 
1-113",  B.  1-138".  (II.  22,  sporang-ium). 
=1  Euastrum  Rota  (Elir.)  in  part.  G.B., 
I.,  F.,  G.,  Italy,  U.S.A.  /3,  ends  broader, 
slightly  hii'sute  at  the  terminal  margin 
(BaUey). 

M.  rotata  (Ralfs). — Frond  orbicular, 
smooth ;  segments  5-lobed ;  basal  lobes 
twice,  middle  lobes  thrice  dichotomous ; 
ultimate  subdivisions  acutely  hidentate; 
end  lobe  very  slightly  exserted,  its 
angles  very  slightly  produced,  bidentate, 
ends  emarginate.  In  transverse  view  is 
seen  an  inflated  protuberance  just  over 
the  central  isthmus,  which  may  possibly 
exist  in  other  species  of  Micrasterias. 
L.  1-91",  B.  1-104".  (i.  20.)  =  Euastru7n 
-Ro!!«(Ehr.,Nag.)  in  part;  Eutomia  rotata 
(Han-ey).     G.B.,  I.,  F.,  G.,  Italy,  U.S.A. 

M.  jimhriata  (Ralfs). — Frond  orbicu- 
lar, smooth ;  segments  5-lobed ;  basal 
lobes  twice,  middle  lobes  generally  thrice 
dichotomous  ;  idtimate  subdivisions  ob- 
tusely emarginate,  each  furnished  with 
two  curved  acute  sjnnes  ;  end  lobe  some- 
what exserted,  the  angles  slightly  pro- 
duced and  rounded,  and  each  fm-nished 
with  two  or  three  minute  spines ;  ends 
concave.  L.  1-108",  B.  l-Ud".=Euas- 
trum  Rota  (Ehr.)  in  part.    G.  B.,  U.  S.  A. 

M.  apiculata  (Menegh.). — Frond  orbi- 
cular, hispid  all  over  with  scattered  spines ; 
segments  5-lobed ;  basal  and  middle  lobes 
once  or  twice  incised,  their  external  mar- 
gin toothed,  ultimate  subdivisions  fur- 
nished with  two  acute  spines  ;  end  lobe 
narrow,  spinous  on  external  margin.  = 
Euastrum  aculeatum  (Ehr.).     G.,  1?\ 


M.  radiosa  (Ag.). — Frond  orbicular, 
smooth  ;  segments  5-lobed  ;  basal  lobes 
twice,  middle  lobes  generally  thrice  di- 
chotomous, ultimate  subdi\dsions  injlated, 
attenuate  towards  the  end,  bidentate  ;  end- 
lobe  emarginate,  its  angles  dentate,  (i. 
21.)  L.  1-138"  ;  B.  ^-1^".  =  Euastrum 
Sol  (Ehr.).     G.  B.,  I.,  F.,  U.  S.  A. 

M.  jjapillifera  (Breb.). — Frond  orbicu- 
lar, having  the  principal  sinuses  bordered 
by  a  row  of  minute  granules,  otherwise 
smooth  ;  segments  5-lobed ;  basal  and 
middle  lobes  twice  dichotomous,  their 
idtimate  shallow  subdivisions  terminated 
by  two,  sometimes  three,  gland-like  teeth  j 
end-lobe  emarginate,  its  angles  dentate. 
Sporangium  as  in  M.  denticulata,  but  con- 
siderably smaller.  L.  l-22r'-l-205" ; 
B.l-238"-l-211".  (i.  18,  spor.  19).  G.B., 
I.,  F.,  U.S.A. 

4t  Frond  orbicular;  segments  5-lobed; 
lobes  approximate,  the  intervals  be- 
tween the  lobes  shallow  narrow  inci- 
sions ;  the  lateral  lobes  dentate,  crenate, 
or  slightly  sinuate;  end  lobe  broad,  not 
exserted.    {a'^b,  c.) 

M.  quadragies-cuspidata  (Ealfs).  — 
Frond  hispid  all  over  with  scattered  minute 
hair-like  spines  ;  segments  5-lobed ;  basal 
and  middle  lobes  slightly  bipartite,  their 
subdivisions  bidentate;  end  lobe  very 
broad,  cuneate,  ti-uncate,  its  angles  biden- 
tate. =  Cosmarium  quadragies-cusjndaimn 
(Corda).     G. 

M.  truncata  (Breb.). — Frond  orbicidar, 
smooth;  segments  5-lobed;  basal  and 
middle  lobes  obscurely  bipartite,  extre- 
mities bidentate  ;  end  lobe  very  broadly 
cuneate,  bidentate  at  the  angles,  and  with 
a  slight  central  conca\'ity.  L.  1-240" ;  B. 
1-250".=  Cosmarium  truncatum  (Corda); 
Euastrum  Rota  (Ehr.)  in  part ;  31.  semi- 
radiata  (Kg.) ;  Euastrum  semiradiatum 
(Nag.).     G.B.,  I.,  G.,  F.,  U.S.A. 

M.  crenata  (Breb.). — Frond  orbicidar, 
smooth ;  segments  5-lobed ;  basal  and 
middle  lobes  usually  crenate,  or  sinuate ; 
end-lobe  very  broadly  cuneate,  rounded 
at  the  ends,  entire.  L.  1-244" ;  B.  1-263". 
G.  B.,  I.,  U.  S.  A. 

5t  Frond  oblong,  elliptic;  segments  5- 
lobed ;  lobes  approximate  or  spreading, 
intervals  between  the  lobes  linear  or 
somewhat  sinuous,  all  the  lobes  similar 
at  the  extremities,  the  end  lobe  the 
broadest,    (a,  b,  <?.) 

M.  Jenneri  (Ralfs).  —  Frond  oblong, 
minutely  granulated;  segments  5-lobed; 
ba^al,    middle,    and  end  lobes  cimeate, 


'28 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


obscurely  bipartite,  and  their  subdivisions  |  (Ealfs),  granules  larger,  giving  a  dentate 
emarf/mate,  or  with  merely  a  slight  cetitral  \  appearance  to  the  margin,  otherwise  as  a. 
coneavity ;  angles  rounded ;  end-lobe  at  i  y  (Archer),  gTanides  giving  a  rough  ap- 
externai  margin  considerably  the  broadest.  |  pearance  to  the  margin,  lobes  slightly 
L.  1-147";  B!^  1-209".  G.B.,  I.  a  (Ralfs),  concave,  margins  rounded,  not  bipartite, 
granules  like  mere  pimcta,  lobes  slightly  i  ^vdthout  emarginate  subdivisions, 
bipartite,   subdi^-isions  emarginate.      ^  ; 

Genus  EUASTRUM  (Ehr.). — Erond  longer  than  broad,  compressed ;  deeply 
constricted  into  two  lobed  or  sinuated  segments  ;  segments  usually  p^Tamidal, 
5-  or  3-lobed  or  merely  ^mxao^x^,  2^ossessing  variously  disposed  circular  inflated 
protuberances  (veiy  rarely  absent) ;  lateral  lobes  opjyosite,  very  rarely  radiant, 
rounded  or  sinuated  at  the  extremities  ;  end  lobes  acutely  incised  or  emargiyiate 
at  the  centre,  rarely  only  concave ;  central  constriction  linear.  (The  inflated 
protuberances  and  the  emarginate  ends  rarely  (if  ever?)  simultaneously 
absent.) 


*  Segments  deeply  lobed;  separating  si- 
nuses directed  inwards  and  downwards ; 
the  end  lobe  cuneate  and  partly  included 
within  the  notch  formed  by  the  projection 
of  the  lateral  lobes. 

EuASTRUM  verrucosum  (Ehr.). — Frond 
somewhat  longer  than  broad,  rough  all 
over  with  conic  granides ;  segments  3- 
lobed,  somewhat  divergent,  all  the  lobes 
broad,  cuneate,  with  a  very  broad  shallow 
external  sinus  (ab,  c). 

Empty  frond :  f.v.  segments  with  one 
large  circular  basal  inflation  on  surface, 
one  smaller  on  each  side,  and  two  others 
on  the  end  lobe ;  s.  v.  segments  inflated  at 
the  base,  narrowed  into  a  short  neck,  end 
dilated  with  a  central  sinus ;  e.\.  oblong, 
with  three  inflations  at  each  side,  one  at 
each  end,  end  lobe  having  4  divergent 
lobelets.  L.  1-267";  B.  1-270".  Cos- 
marium  verrucosum  (Menegh.),  E.  papu- 
losum  (Kg.).  G.B.,  I.,  G.,  F.,  Italy, 
U.S.A. 

E.  oblongum  (Ralfs).  —  Frond  rather 
more  than  twice  as  long  as  broad,  smooth, 
oblong ;  segments  5-lobed ;  lobes  nearly 
equal,  cuneate ;  lateral  lobes,  or  the  basal 
only,  with  a  broad,  shallow,  marginal 
concavity,  all  their  angles  rounded,  ter- 
minal notch  linear  (a,  b,c). 

Empty  fi'ond :  f.  v.  seg.  pimctate,  with 
three  large  inflations  on  smface  near  the 
base,  two  others  above  and  two  on  ter- 
minal lobe ;  tr.  v.  three  times  as  long  as 
broad,  with  three  subdistant  marginal 
inflations  at  each  side,  and  one  at  each 
end,  in  /3  broader  in  proportion,  more 
elliptic,  and  inflations  close  ;  e.  v.  end 
lobe  notched  at  opposite  external  mar- 
gins. Sporangium  orbicular,  beset  with 
numerous  conical  tubercles.  L.  1-156" ; 
B.  1-282".  {iuA\.)  =  Echinella  oblonga 
(Ch-cv.);  Euastrum  Pecten  (FAiw);  Cosma- 


7'ium  sinuosum  (Corda)  ;  Eidomia  oblonga 
(Harv.).  G.B.,  I., F.,G.,  Italy, U.S.A.  ^ 
smaller,  narrower,  middle  lobes  rounded, 
without  any  marginal  concavity. 

E.  crassum  (Kg.). — Frond  about  twice 
as  long  as  hxoeidL,subquadrilateral,Bm.ooth.; 
segments  3-lobed  ;  basal  lobes  very  broad, 
with  a  vei'y  broad,  shalloio  marginal  sinus, 
in  which  there  is  sometimes  a  slight  in- 
termediate rounded  projection ;  end  lobe 
cuneate,  roimded,  terminal  notch  linear. 
{ab,  c.) 

Empty  frond  :  f.  v.  punctate,  segments 
"^dth  three  inflations  below  and  two 
above ;  tr.  v.  two  or  three  times  longer 
than  broad,  with  three  lobes  or  inflations 
at  each  side  and  one  at  each  end ;  e.  v. 
end  lobe  sinuate  at  opposite  external 
marffms.  L.  1-193"-1-132" ;  B.  1-263". 
=^.Pelta  (Hass.).  G.  B.,  I.,  F.,  G., 
U.  S.  A.  ^  smaller,  margins  of  lateral 
lobes  more  concave,  sinuations  between 
the  lateral  and  end  lobes  more  closed, 
the  latter  more  included. 

E.  cornutum  (Kg.). — Frond  abouttwice 
as  long  as  broad:  segments  3-lobed,  some- 
what inflated  at  base,  outer  tipp)er  angles 
of  based  portion  prolonged  into  a  process- 
iike  projection  directed  upwards  ;  end 
lobe  included,  its  notch  broad,  concave. 

Empty  frond  punctate,    {ab,  c.)    G. 

2  *  Segments  sinuously  lobed,  or  tapering; 
end  lobe  exserted  and  united  to  the  basal 
portion  by  a  distinct  neck. 

t  End  lobe  with  a  linear  or  acute  notch. 

E.  2nnnatum  (Ralfs).  — Frond  oblong, 
about  twice  as  long  as  broad ;  segments 
5-lobed  in  a  pinnatifid  manner,  basal 
lobes  slightly  emarginate,  middle  smaller, 
rounded,   entire,  end  lobe  exserted,  di- 


OF  THE  DESMIDIE^. 


729 


lated,  its  notch  linear ;  the  upper  margin 
of  the  lobes  horkontal.     (a,  6,  c.) 

Empty  frond:  f.  v.  segments  punc- 
tate, usually  with  two  large  inflations 
near  the  base,  fom^  smaller  between, 
three  others  above,  and  two  on  end  lobe  ; 
s.  Y.  central  constriction  deep,  segments 
inflated  at  the  base,  then  contracted, 
again  inflated,  and  again  contracted  be- 
neath the  dilated  temiinal  lobe  ;  tr.  t. 
with  four  lobes  or  inflations  on  each  side, 
and  one  at  each  end ;  e.  v.  end  lobe  with 
a  deep  sinus  at  opposite  external  mar- 
gins, concave  at  the  sides,  so  as  to  produce 
four  divergent  lobelets.  L.  1-188"  ;  B. 
1-454".     G.B. 

E.  humerosum  (Ralfs). — Frond  about 
twice  as  long  as  broad ;  seg-ments  sub- 
6-lobed ;  basal  lobes  slightly  emarginate ; 
middle  lobes  narroic,  directed  iqnvards, 
resembling  processes  ;  end  lobe  with  a 
short  neck,  partly  included  between  the 
middle  lobes,  dilated,  its  notch  linear. 
{a,  h,  c.) 

Empty  frond  minutely  punctate ;  f.  v. 
segments  with  three  inflations  at  base, 
two  above  and  two  on  end  lobe ;  tr.  v. 
elliptic,  with  three  inflations  on  each 
side  and  one  at  each  end.  L.  1-225" ; 
B.  1-382".     G.B.,  I.,  F. 

E.  affine  (Ralfs). — Frond  about  twice 
as  long  as  broad ;  segments  3-lobed  ;  basal 
lobes  slightly  emarginate,  having  inter- 
mediate between  them  and  the  end  lobe 
on  each  side  a  tubercle  representing  mid- 
dle lobes,  the  tipper  margin  of  tvhich  is 
horizontal',  end  lobe  exserted,  dilated, 
its  notch  linear.    (a&,  c.) 

Empty  frond :  f  v.  minutely  punctate ; 
the  segments  wdth  four  basal  inflations, 
two  above  and  two  on  end  lobe ;  tr.  v. 
elliptic,  with  fom*  inflations  on  each  side 
and  one  at  each  end ;  e.  v.  end  lobe  emar- 
ginate at  opposite  external  margins,  pro- 
ducing four  shallow  lobelets.  L.  1-230" ; 
B.  1-458".     G.B.,  I.,  F.,  U.S.A. 

E.  ampullaceum  (Ralfs). — Frond  rather 
more  than  one-half  longer  than  broad ; 
segments  obscurely  3-lobed,  short,  with 
broad  injiated  base  \  basal  lobes  not  emar- 
ginate, having  on  each  upper  side  a  small 
intermediate  tubercle  between  each  and 
the  end  lobe  ;  end-lobe  exserted  and  di- 
lated, its  notch  linear,  {ab,  c.)  Empty 
frond  minutely  pimctate  ;  f.  v.  inflations 
indistinct  or  confluent ;  s.  v.  narrow  el- 
liptic, ^N-ith  several  inflated  protuber- 
ances, ends  scarcely  dilated,  rounded ; 
tr.  V.  with  four  inflations  at  sides  and 
one  at  each  end.  L.  1-274" ;  B.  1-394". 
G.B.,  I.,  F.,  U.S.A. 

E.  insigne  (Hass.). — Frond  rather  more 


than  twice  as  long  as  broad :  segments 
inflated  at  base,  sides  entire,  icithout  late- 
ral tubercles,  and  tapering  into  a  long 
slender  neck ;  end  lobe  dilated,  its  notch 
linear,    {ab,  c.) 

Empty  frond  minutely  punctate  ;  £  v. 
segments  with  ttvo  injlcitions  at  the  base ; 
s.  V.  naiTower,  gi'adually  tapering  to  the 
end,  which  is  considerably  dilated ;  pro- 
jections roimded,  with  a  sinus  between  j 
tr.  V.  subquadrate,  slightly  concave  at 
sides,  with  a  rounded  lobe  at  the  centre 
of  each  end ;  e.  v.  end  lobe  with  a  sinus 
at  opposite  external  margins,  angles  thus 
protruded  into  foiu'  divergent  roimded 
lobelets.  L.  1-232" ;  B.  1-416".  (in.  12.) 
G.B.,  I.,  U.S.A. 

E.  Didelta  (Ralfs). — Frond  rather  more 
than  twice  as  long  as  broad ;  segments 
pyramidal,  injiated  at  the  base  and  again  at 
the  middle,  end  scarcely  dilated,  roimded, 
its  notch  linear,    {a'^b,  c.) 

Empty  frond  pimctate ;  f.  v.  segments 
with  severed  inflations  in  lines  and  two 
at  the  end ;  tr.  v.  elliptic  with  four  injia- 
tions  at  each  side  and  one  at  each  end: 
e.^  V.  end  lobe  entire  at  margin.  Sporan- 
gium orbicular,  with  subulate  spines. 
(I.  23, 24,  tr.  V.  25.)  L.  1-185";  B.  1-357". 
=  CosiyiaritmiDideltai^lenegh.),  E,  bi?iale 
(Kg.).     G.B.,  I.,  F.,  Italy,  U.S.A. 

E.  ansatum(H]iv.). — Frond  about  twice 
as  long  as  broad;  segments  inflated  at 
the  base,  tajjering  upwards  without  sinua- 
tions  into  a  neck,  end  not  dilated,  roimded, 
its  notch  linear,    {ab,  c.) 

Empty  frond  punctate ;  f.  v.  segments 
turgid  on  the  sui'face,  at  the  middle  with- 
out circular  inflations;  tr.  v.  elliptic,  with 
a  single  large  inflation  at  each  side  ;  e.  v. 
end  lobe  entire  at  the  margin,  its  divisions 
circular.  L.  1-315";  B.  1-654". =^.  bimde 
(Kg.),  Cosmarium  ansatum  (Kg.).  G.B., 
1.,  F.,  G.,  Italy,  U.S.A. 

E.  circulare  (Hass.). — Frond  about 
trvdce  as  long  as  broad,  tapering  upwards 
into  a  neck,  end  not  dilated,  its  notch  an 
acute  incision,    {ab,  c.) 

Empty  frond  :  segments  withflve  basal 

iiflations,  four  in  a  half  circle  round  the 

flfth,  and  two  others  at  the  extremity. 

=  Cosmarium  circulare  (Kg.),  E.  circulare, 

var.  mtssallii  (Bveh.).     G.B.,  F.,  U.S.A. 

E.  sinuosum  (Lenormand).  —  Frond 
about  t^sdce  as  long  as  broad,  segments 
3-lobed,  basal  portion  emarginate  at  the 
sides;  end  lobe  somewhat  dilated,  its 
notch  linear,    {ab,  c.) 

Empty  frond  punctate ;  segments  with 
flve  based  inflations  and  two  others  at  ex- 
tremity ;  tr.  V.  elliptic,  with  three  infla- 
tions at  each  side  and  one  at  each  end. 


'30 


SYSTEMATIC  HISTORY  OF  THE  INFTTSORIA. 


L.  1-325" ;  B.  1-549".  =  E.  circidare  ^ 
(Rfs.),  JE.  circular c,  var.  Falasiemis 
(Breb.).     G.B.,  R 

E.  Jemieri  (nobis). — Frond  scarcely 
twice  as  long  as  broad ;  segments  3-lobed, 
basal  portion  suhquadrate,  emarginate  at 
the  sides ;  end  lobe  somewhat  dilated,  its 
notch  linear,    (ah,  c.) 

Empty  frond  punctate,  segmetits  with 
several  small  injlations  arranged  in  alter- 
nate lines.  =E.  circidare  y  (Ralfs),  E.  cir- 
cidare, var.  Ralfsii  (Breb.).     G.B.,  F. 

Mr.  Ealfs  unites  this  and  the  two  pre- 
ceding as  three  varieties  of  E.  circidare 
(Hass.).  They  seem,  however,  to  be 
quite  as  distinct  as  any  other  species  de- 
scribed, not  only  in  external  outline,  but 
also  in  the  distribution  of  the  supei-ficial 
inflations. 

2 1  End  lobe  straight  or  concave  without 
a  central  notch. 

1^.  pectinatum  (Breb.). — Frond  rather 
more  than  twice  as  long  as  broad  ;  seg- 
ments 3-lobed,  basal  portion  suhquadri- 
lutei'al'j  lateral  lobes  horizontal,  deeply 
emarginate,  end  lobe  much  dilated, 
straight  or  slightly  concave  at  ends,  angles 
entire  or  emarginate.  (ab,c.)  Emptyfrond 
punctate ;  f.  v.  segments  with  three  in- 
flations near  the  base ;  tr.  v.  elliptic  with 
three  inflations  at  each  side  and  two  at 
each  end ;  e.  v.  end  lobe  with  two  minute 
lobelets  at  each  end,  and  two  near  them 
at  each  side.  Sporangium  orbicular,  beset 
with  conical  tubercles,  (ii.  10  &  30.) 
L.  1-362  ' ;  B.  1-558".     G.B.,  I.,  F. 

E.  gemmatum  (Kg.,  Breb.). — Frond 
scarcely  twice  as  long  as  broad ;  segments 
3-lobed,  lateral  lobes  horizontal,  deeply 
emarginate,  the  protuberances  minutely 
gratiidate;  end  lobe  dilated,  its  dilata- 
tions inclined  upivards,  and  minutely 
granulate ;  ends  tcith  a  deep  rounded  emar- 
gination.  {ah,  c.)  Empty  frond  slightly 
punctate;  f.  v.  segments  with  three 
granulate  inflations  near  the  base  ;  tr.  v. 
broadly  elliptic,  with  three  granulate  in- 
flations at  each  side  and  one  at  each 
end ;  e.  v.  end  lobe  cruciform,  lobe- 
lets  rounded,  gTanulate.  L.  1-443"  ; 
B.  1-641".  =  Euastrum  {Eucosmium) 
Hassallianum  (Nag.).  G.B.^  I.,  F., 
Prussia. 

3*  Frond  loithout  a  distinct  terminal  lohe, 
frequently  having  a  process  or  ^  acute 
angle  at  corners  of  terminal  portion. 

E.  rostratum  (Ralfs). — Frond  scarcely 
twice  as  long  as  broad,  oblong ;  segments 
with  their  laasal  portion  deeply  emargi- 
nate at  the  sides,  connected  by  a  broad 


neck  with  the  teiininal  portion;  ends 
protuberant,  angular,  acutely  emarginate 
at  the  centre,  and  having  at  eacli  side 
a  horizontal  subacute  projection,  (ah,  c.) 
Sporangium  orbicular,  spinous;  spines 
conical,  attenuated.  L.  1-650"  to  1-580" ; 
B.  1-1000"  to  1-714".  (I.  26.)  G.B., 
I.,  F.,  U.S.A. 

E.  p)ulchellum  (Breb.). — Frond  rather 
more  than  one-third  longer  than  broad, 
oblong ;  segments  with  the  basal  portion 
twice  or  thrice  acutely  dentate  at  each  in- 
flated basal  angle,  and  connected  by  a 
broad  neck  with  the  terminal  portion ; 
ends  strcught,  acutely  emarginate  at  the 
centre,  angles  acutely  mucronate ;  e.f. 
bearing  at  the  centre  of  each  segment  a 
single  inflated  prominence  bordered  by  an 
annular  series  of  granules  (in  s.v.  trun- 
cate), and  a  few  scattered  gTanules  near 
the  projecting  parts,    {ah,  c.)     F. 

E.  e/('//f//?s(Breb.,Kg.). — Frond  minute, 
scarcely  t^vdce  as  long  as  broad,  oblong ; 
segments  -wdth  their  basal  portion  emar- 
ginate at  the  sides,  connected  by  a  broad 
neck  ^s-ith  the  terminal  portion;  ends 
protuberant,  rounded,  acutely  emarginate 
at  the  centre,  pouting  ;  s.v.  with  an  infla- 
tion at  the  base  of  the  segments,  sides 
concave,  ends  rounded,  {ah,  c.)  Sporan- 
gium orbicular,  spinous.  =  E.  bidentatum 
(Nag.).  G.B.,I.,F.,G.,U.S.A.  a,  neck 
somewhat  constricted,  end  portion  bear- 
ing on  each  side  an  acute  horizontal 
spine-like  projection.  L.  1-888"  to 
1-445"  ;  B.  1-1441"  to  1-714".  /3,  seg- 
ments sinuated,  neck  not  constricted  and 
without  spines.  L.  1-421";  B.  1-654". 
y,  neck  not  constricted,  lateral  projec- 
tions bearing  minute  spines  directed  ob- 
liquely outwards.  =  E.  spinosum  (Hass.). 
L.  1-884";  B.  1-1388". 

E.  crenatum  (Kg.).  —  Frond  very 
minute,  about  twice  as  long  as  broad, 
segments  pyramidal,  their  lateral  margin 
crenate,  ends  broad,  truncate,  entire, 
{ah,  c.)     F.,  G. 

E.  hinah  (Ralfs). — Frond  veiy  minute, 
scarcely  twice  as  long  as  broad,  oblong ; 
segments  with  their  basal  portion  either 
entire  or  bicrenate  at  the  sides,  slightly 
contracted  beneath  the  ends ;  ends  di- 
lated, not  jjrotuberant  beyond  the  angles, 
its  central  notch  acute,  broad  ;  tr.v.  with 
two  lateral  inflations,  ends  truncate, 
angles  rounded,  {ahc.)  L.  1-1570"  to 
1-1428";  B.  1-2400"  to  1-1400".  (in.  13.) 
=  Heterocarpella  binalis  (Turp.),  C'os- 
marium  binale  (Meneghini),  E.  Ralfsii 
(Kg.),  E.  lohdatum  (Breb.)  ?  E.  duhium 
(Nag.).  G.B.,  I.,  F.,  U.S.A.  ^,  frond 
rather  larger,  rough,  with  a  few  scattered 


OF  THE  DE«MIDIEiE. 


'31 


granules ;  margins  of  segments  crenate  ; 
acute  angles  of  end  portion  sliglitly 
horizontally  prolonged,  its  notch  small, 
rounded  (probably  a  distinct  species). 

E.  cuneatum  (Jenner).— Frond  large, 
rather  more  than  twice  as  long  as  broad  ; 
segments  pp-amidal,  broadest  at  base  and 
naiTOwing  upwards,  not  lohcd,  the  sides 
almost  straight-,  ends  trmicate,  central 
notch  linear,    (a'^b^'^c.)     Empty  frond 


without     inflated     protuberances.       L. 
1-208"  ;  B.  1-420".     G.B.,  I. 

E.  pelta  (Kg.). — Frond  about  t^\'ice  as 
long  as  broad,  oblong  ;  segments  quadrate, 
each  lateral  margin  with  a  small  rounded 
protuberance  or  injlation  at  the  base, 
another  larger  near  the  tipper  end,  and 
another  somewhat  larger  still  at  the  ujjper 
angle ;  ends  straight,  not  notched,  (ab,  c.) 
=  Cosmarium  Pelta  (Corda).     G. 


Genus  COSMARIUM  (Corda). — Frond  more  or  less  constricted ;  segments 
undivided,  usually  rounded,  sometimes  slightly  sinuated,  or  rarel}^  slightly 
contracted,  somewhat  extended  and  truncate  at  the  ends,  never  notched, 
neither  pro^-ided  with  spines  nor  processes;  e.v.  elliptic,  and  sometimes  each 
side  wdth  a  lateral  opposite  inflation,  or  circular. 


*  Frond  compressed ;  central  constriction 
a  dee]),  nsuallg  linear,  incision ;  e.v. 
compressed,  either  elhptic  or  subcruci- 
form,  oicing  to  the  jjrojection  at  each 
side  of  a  protuberance  or  injlation. 

t  Margins  of  segments  entire,  neither 
crenate  nor  gi-anulate. 

Cosmarium  sublobatum  (Breb.  sp). — 
Frond  scarcely  twice  as  long  as  broad, 
oblong;  constriction  linear,  segments 
subquadrate,  somewhat  wider  at  the  base, 
lateral  and  end  margins  slightly  concave, 
smooth,  transverse  view  cruciform.  L. 
1-523" ;  B.  1-646".  =  Euastrum  ?  sid)lo- 
batum  (Breb.).     G.B.,  I.,  F.,  U.S.A. 

C.  pusiUum  (Breb.  sp.). — Frond  very 
minute,  slightly  broader  than  long,  con- 
striction acute,  segments  angulato-tra- 
pezoid,  slightly  naiTO\\dng  upwards, 
smooth,  angles  rounded,  ends  slightly 
concave.  =  Euastnnn pi(sillum(^i'eh.).  F. 

C.  quadratum  (Ralfs). — Frond  about 
twice  as  long  as  broad,  constriction  deep, 
linear ;  segments  quadrate,  slightly  pro- 
tuberant  on  each  side  at  the  base,  with 
rounded  angles  at  the  ends,  smooth  ;  e.v. 
compressed.  L.  1-510";  B.  1-952". 
G.B.,  F. 

C.  Qwumis  (Corda). — Frond  about 
twice  as  long  as  broad ;  constriction 
deep,  linear  ;  segments  as  broad  as  long, 
with  the  basal  angles  rounded,  broadly 
rounded  at  ends,  smooth  ;  e.v.  elliptic. 
L.  1-362"  to  1-257";  B.  1-568"  to  1-502". 
—  Euastrum  integerrimumCEhv.).  G.B., 
I.,  F.,  G.,  Italy,  U.S.A. 

_C.  Halfsii  (Breb.). — Frond  large, 
slightly  longer  than  broad,  orbicular, 
constriction  deep,  linear ;  seginents  semi- 
orbicular,  rounded  at  basal  angles, 
smooth  ;  e.v.  elliptico-lanceolate  ;  endo- 
chrome  radiate.  L.  1-227";  B.  1-270". 
=  C  Cucumis  (Hass.).     G.B.,  I.,  F. 


C.  rupestre  (Niig.  sp.). — Frond  rather 
more  than  twice  as  long  as  broad,  con- 
striction not  deep  but  linear ;  segmeyits 
broadly  oval,  turgid,  sides  and  ends 
broadly  rounded,  smooth ;  e.£  punctate, 
puncta  scattered.  =  Euastrum  rupestre 
(Nag.).     G. 

C.  pyramidatum  (Breb.).  —  Frond 
scarcely  twice  as  long  as  broad,  suboval ; 
constriction  deep,  linear ;  segments  p}Ta- 
midal,  rounded  at  basal  angles,  somewhat 

\  truncate  at  the  ends,  punctate;  e.v. 
broadly  elliptic.  Sporangiimi  orbicular, 
tuberculated.  L.  1-471"  to  1-264" ;  B'. 
1-759" to  1-374".  (ill.  14,  e.v.  \b.)  =  Pi' 
thiscus angulosus (Kg.).  G.B.,I.,F.,U.S.A. 
C.  lagenarium  (Corda). — Frond  about 
t^-ice  as  long  as  broad,  subelliptic ;  seg- 

j  ments  triangular,  pyramidal,  punctate; 
basal  angles  broadly  rounded,  sides  some- 

1  ivhat  concave,    tapering,    ends    broadly 

I  rounded.  =  C.  ansatum  (Kg.).     G. 

I      C.    tinctum     (Ralfs).  —  Frond     very 

I  minute,  about  as  long  as  broad,  constric- 
tion producing  an  acute  notch  at  each 
side ;    segments  elliptic,  about  twice  as 

[  broad  as  long,  smooth  ;  e.v.  narrow 
elliptic.  Empty  frond  someivhat  reddish. 
Sporangium  quadrate,  smooth,  -with  an 
empty  segment  of  the  conjugated  fronds 
permanentlv  attached  to  each  comer. 
L.  1-2325"  ;  B.  1-2500".     G.B.,  I. 

C.  bioculatum  (Breb.). — Frond  minute, 
about  as  long  as  broad;  constriction 
deep,  producing  a  gaping  notch  at  each 
side ;  segments  about  twice  as  broad  as 
long,  elliptic,  smooth;  s.v.  compressed; 
e.v.  elliptic.  Sporangium  orbi<ndar,  ivith 
conical  spines.  L.  1-1416" ;  B.  1-1773". 
G.B.,  I.,  F.,  U.S.A. 

C.  depressum  (Bailey).  —  Frond  de- 
pressed, broader  than  long,  constriction 
a  deep,  narrow,  acute  notch;  segments 
about  twice  as  broad  as  long,  angular  at 


r32 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


base,  broadly  rounded  at  etids,  smooth. 
U.S.A. 

C.  granatum  (Breb.). — Frond  minute, 
somewhat  longer  than  broad;  constric- 
tion linear ;  seg-ments  broader  than  long, 
rajiidly  tapering  ^  truncato-trianguku ; 
smooth;  s.v.  compressed;  e.v.  elliptic. 
L.  1-1234";  B.  1-1602".     G.B.,  I.,  F. 

C.  polygomim  (Niig.  sp.). — Frond  mi- 
nute, about  one-third  longer  than  broad, 
constriction  shallow,  linear;  segments 
hexagonal,  sometimes  punctate,  lateral 
margins  and  ends  straight;  e.v.  elliptic 
with  a  broad  rounded  inflation  at  each 
side. = Euastrmn  polygonum  (Nag.^.    G. 

C.  Phaseolus  (Breb.). — Frond  in  f.v. 
about  as  long  as  broad,  constriction  deep, 
linear;  segmetits  reniform,  smooth;  e.v. 
elliptic,  with  a  slight  conical  projection  at 
each  side.  L.  1-787" ;  B.  1-833".  =K 
depressum  (Nag.)  ?     G.B.,  I.,  F. 

C.  Papilio  (Menegh.).  — "  Segments 
smooth,  triangular,  with  rectangular 
apex,  sides  very  slightly  sinuato-undu- 
late,  lateral  angles  produced,  acute ;  e.v. 
linear  with  a  lobe  at  middle  of  each  side.^^ 
Euastrum  ?  Papilio  (Kg.).     G.,  Italy. 

2t  Margins  of  segments  crenate  or 
slightly  undulate,  sm'face  not  granu- 
late. 

C.  Meneghinii  (Breb.). — Frond  very 
minute,  rather  longer  than  broad,  con- 
striction linear;  segments  subquadrate, 
bicrenate  at  the  sides  and  ends,  smooth ; 
e.v.  elliptic.  L.  1-853"  to  1-735";  B. 
1-1250"  to  1-1176".  =  C.  bioculatum 
(Menegh.),  Euastrmn  bioculatum  (Kg.), 
E.  angulosmn  (Breb.),  E.  crenulatum 
(Nag.).     G.B.,  I.,  F.,  G.,  Italy,  U.S.A. 

C.  crenatum  (Ralfs). — Frond  minute, 
not  quite  twice  as  long  as  broad,  con- 
striction linear ;  segments  obsoletely 
quadrate,  crenate  at  the  margin,  Jlattened 
at  ends,  surface  punctate;  e.v.  elli]3tic. 
Sporangium  orbicular,  spinous ;  spines 
very  short  and  stout,  swollen  at  base, 
and  di\dded  at  the  apex.  L.  1-474"  ; 
B.  1-Q7 8".  =Euastru7n?  sinuosum  (Kg.). 
G.B.,  I.,  F. 

C.  undulatum  (Corda). — Frond  rather 
larger  than  last,  slightly  longer  than 
broad,  constriction  linear;  segments 
semiorbicular,  ends  and  sides  broadly 
rounded,  crenate  or  minutely  undulate 
at  margin;  e.v.  elliptic.  Sporangium 
orbicular,  spinous ;  spines  elongate,  slen- 
der, swollen  at  the  base  and  divided  at 
the  apex.  L.  1-416" ;  B.  1-571".  (ii. 
33,  spor.  34).  =  Euasfrum  crenulatum,  c 
(Nag.)?     G.B.,  I.,  F.,  U.S.A. 


C.  Nesgelianum  (Breb.). — Frond  in  f.v. 
slightly  longer  than  broad,  constriction 
deep,  linear ;  segments  broad  at  the  base, 
rapidly  narroiving  upwards,  sides  ivith 
several  minute  sinuations,  ends  broadly 
truncate,  straight  or  very  slightly  undu- 
late, obscm-ely  punctate ;  e.  v.  elliptic, 
sometimes  somewhat  inflated  at  the 
sides.  =  Euastrmn  (Costnariimi)  crenatum 
(Nag.).     F.,G. 

C.  tetragonum  (Nag.  sp.). — Frond  in 
f.v.  about  twice  as  long  as  broad,  oblong, 
constriction  linear;  segments  subquad- 
rate,  somewhat  narrowing  from  the  base, 
sides  and  end  each  with  three  slight 
sinuations,  those  of  the  ends  rather 
smaller,  in  each  half  one  large  central 
granide ;  s.v.  segments  oval,  roimded, 
constriction  shallow.  =  Euastrum  tetra- 
gonum (Nag.).     I.,  G. 

C.  venustum  (Breb.  sp.). — Frond  some- 
what longer  than  broad,  constriction 
deep,  linear ;  segments  slightly  narrowed 
upwards,  ivith  two  somewhat  deep  sinua- 
tions at  the  sides,  ends  broad,  truncate, 
slightly  concave  at  the  centre.  =  Euastrmn 
venustum  (Breb.).     F. 

3t  Fronds  rough  on  the  surface,  with 
pearly  granules,  which  give  a  denticu- 
late appearance  to  the  margin. 

C.  tetraophthalmum  (Kg.,  Breb.). — 
Frond  about  a  third  longer  than  broad, 
constriction  deep,  linear;  segments/o;7«- 
ing  nearly  two-thirds  of  a  circle,  rough  on 
the  surface  with  sho?'t  and  broad  scattered 
pearly  granules,  giving  a  crenate  appear- 
ance to  the  margin  ;  e.v.  broadly  elliptic. 
Sporangium  orbicular,  spinous ;  spines 
swollen  at  base,  finelv  oranched.  L. 
1-232"  ;  B.  1-1326".    "^G.B.,  I.,  G.,  F. 

C.  Brebissonii  (Menegh.). — Frond 
somewhat  longer  than  broad,  constric- 
tion deep,  linear ;  segments  semiorbicular, 
rough  all  over  with  somewhat  elongate- 
conical  scattered  pearlv  granules  ;  e.  v. 
eUiptic.  L.  1-285";  B.  1-460".  =  C.  mar- 
garitiferum  (Kg.)  ?     G.B.,  I. ,  F.,  G. 

C.  conspersum  (Ealfs). — Frond  about 
a  third  longer  than  broad,  constriction 
deep,  linear;  segments  quadrilateral, 
angles  roimded,  rough  all  over  with  de- 
pressed  gTanules  aiTanged  in  lines ;  e.v. 
elliptic.  L.  1-162";  B.  1-357".  =  a 
Brebissonii  (Menegh.).''     G.B.,  F. 

C.  Ungerianum  (Nag.). — Frond  large, 
rather  longer  than  broad,  constriction 
deep,  linear  ;  segments  much  inflated  at 
the  base,  angles  and  sides  rounded,  nar- 
rowing upwards,  ends  broadly  truncate, 
rough  at  the  margin,  with  a   few  large 


OF  THE  DESMIDIE^. 


733 


rounded  pearly  fframdes  placed  in  lines, 
the  disc  j^afictate ;  e.  v.  broadly  elliptic, 
the  large  pearlv  gTanules  confined  to  the 
rounded  extremities,  regularly  disposed  in 
a  few  evident  lines,  the  intermediate 
central  space  punciate.  "  L.  1-37'" ;  B. 
\-4S"'.^'  =  JSuastrum  {Cosmariuni)  JJn- 
(jerianum  (TSag.).     G. 

C.  ovale  ( Ralfs).  —  Frond  A'ery  large, 
elliptic,  nearly  twdce  as  long  as  broad, 
constriction  very  deep,  linear ;  segments 
somewhat  broader  than  long,  somewhat 
triangular,  rounded  at  ends,  rough  near 
the  margin,  ivith  a  hand  of  large  pearly 
granules,  producing  a  dentate  appear- 
ance, the  disc  punctate ;  e.  v.  elliptic. 
L.  1-139" ;  B.  1-240".     G.B.,  R,  U.S.A. 

C.  prcsmorsuni  (Breb.). — Frond  rather 
longer  than  broad,  constriction  deep, 
linear  ;  segments  broadly  reniform,  sides 
rounded,  ends  somewhat  trimcate,  rough 
with  pearly  granides,  an  annular  series 
of  tchich,more  elevated  than  the  rest,  forms 
a  ridge  at  the  end  hounding  a  circular 
depression  ;  e.  v.  elliptic.     F, 

C.  margaritifenmi  (Menegh.). — Frond 
about  as  long  as  broad,  constriction  deep, 
linear;  segments  reniform  or  semiorhi- 
cular,  rough  cdl  over  ivith  round  and 
scattered  pearly  granules;  e.  v.  elliptic. 
Sporangium  orbicidar,  spinous ;  spines 
branched  at  apex.  L.  1-566"  to  1-306" ; 
B.  1-694"  to  1-416".  (I.  l.)=Ursinella 
margaritifera  (Turpin),  Euastrum  mar- 
qaritiferum  (Ehr.,  Nag.),  C.  punctulatum 
(Breb.)  ?  G.B.,  I.,  F.,  G.,  Italy,  U.S.A., 
Mexico. 

C.  Portianum  (Archer). — Frond  about 
one-third  longer  than  broad,  constriction 
deep,  tcide,  somewhat  round  below,  isth- 
mus forming  a  short  neck ;  segments  ellip- 
tic, rough  all  over  with  minnte  scattered 
pearly  granules',  e.  v.  elliptic.  L.  1-600"; 
B.  1-930".     I. 

C.  latum  (Breb.). — Frond  large,  about 
as  broad  as  long,  constriction  deep,  sub- 
linear;  segments  reniform,  rough  with 
roimded  pearly  granules  arranged  in 
someichat  curved  transverse  lities;  e.v.  ?  F. 

C.  notahile  (Breb.). — Frond  about  one- 
third  longer  than  broad,  constriction 
somewhat  deep,  acute ;  segments  slightly 
longer  than  broad,  broadest  at  the  base, 
gradually  narrowing  -upwards,  sides  con- 
vex, ends  trimcate,  rough  all  over  with 
broad  pearly  gi-anules,  giving  a  crenate 
appearance  to  the  margin  (endochrome 
in  bands) ;  e.  v.  oval,  turgid.  Sporan- 
gium orbicidar,  beset  with  numerous 
short  stout  spines,  inflated  at  the  base, 
and  deeply  divided  at  the  apex.     F.,  G. 

C.  amoenum  (Breb.). — Frond  twice  as 


long  as  broad,  sides  parallel,  ends  rounded, 
constriction  deep,  linear;  segments  rough 
with  croivded  obtuse  papilla-like  pearly 
granules ;  s.  v.  much  compressed,  about 
thrice  as  long  as  broad  ;  e.  v.  elliptic. 
L.  1-568" ;  B.  1-1141".    G.B.,  F.,  U.S.A. 

C.  Botrxjtis  (Menegh.).— Frond  rather 
longer  than  broad,  constriction  deep, 
linea:- ;  segments  twice  as  broad  as  long, 
broadest  at  base,  narroiving  upwards,  sides 
rather  rounded,  ends  truncate,  rough  all 
over  with  scattered  rounded  pearly  gra- 
nules ;  e.  V.  broadly  elliptic.  Sporangiimi 
orbicular,  spinous;  spines  elongate  and 
slightlv  di\4ded  at  the  apex.  L.  1-469" 
to  1-327";  B.  1-625"  to  1-^19".  =  If ete- 
rocarjjella  Botrytis  (Bory),  C.  deltoides 
(Corda),  Euastrum  Botrytis  (Ehr.,  Kg., 
Niig.),  E.  angulosum  (Ehr.).  G.B.,  I., 
G.,  F.,  Italy,  U.S.A. 

C.2)rotrdctu7n  (Nag.  sp.).— Frond  about 
as  broad  as  long,  constriction  deep, linear; 
segments  twice  as  broad  as  long,  infiated 
and  broadest  at  the  base,  rapidly  tcqyering 
into  a  somewhat  evident  neck,  sides  very 
concave,  ends  abruptly  tnmcate,  rough  all 
over  with  scattered  pearly  granules  ; 
e.  V.  broadly  elliptic,  slighfl'y  infiated  at 
the  middle,  and  gi-adually  sloping  to  the 
rounded  ends.  L.  1-55"'  to  1-33'".  = 
Euastrum  protr actum  (Nag.).     G. 

C.  gemmifermn  (Breb.  in  lit.  c.  ic). — 
Frond_  in  f.  v.  about  as  long  as  broad, 
constriction  deep,  sublinear;  segments 
broadest  at  the  base,  gradually  narrowing 
upwards,  sides  convex,  ends  truncate, 
rough  all  over  with  pearly  gTanules, 
somewhat  aiTanged  in  radiating  lines, 
each  segment  furnished  at  the  middle, 
on  both  surfaces,  ivith  a  rounded  protu- 
berance bordered  with  gramdes  ;  e.  v. 
broadly  elliptic,  with  the  central  tnm- 
cate protuberance  on  each  side.     F. 

C.  Turpimi  (T3reb.).— Frond  about  as 
long  as  broad,  constriction  deep,  linear  ; 
segments  twice  as  broad  as  long,  some- 
what triangidar,  much  infiated  and 
broadly  rounded  at  the  base,  rapidly  at- 
tenuated, sides  concave,  ends  tiWcate, 
rough  all  over  with  scattered  pearly 
granules,  and  with  a  central  gi-anulated 
protuberance ;  e.  v.  yiarroic-elliptic,  with 
the  central  broad  truncate  protuberance 
on  each  side.  =  Heterocarpella  Bidelta 
(Tuq3in),  C.  Bidelta  (I^g.).     F.,  G. 

C.  biretum  (Breb.).  —  Frond  in  f.  v. 
about  as  long  as  broad,  constriction  deep, 
linear;  segments  quadrilateral  or  sub- 
hexagonal,  narrowest  at  the  base  and 
dilated  upwards,  convex  or  somewhat 
truncate  at  ends,  rough  all  over  with 
small    granules    arranged   somewhat   in 


734 


SYSTEMATIC  HISTORY  OF  THE  INEUSOEIA. 


lines ;  e.  v.  with  a  rounded  lobe  on  each 
side  and  roimded  at  ends.  L.  1-333" ; 
B.  1-372".  G.B.,  F.  Var.  triqiietrum 
(Breb.)  :  e.  v.  with  three  rounded  angles, 
sides  deeply  sinuous ! 

C.  Broomei  (Thwaites).  —  Frond  in 
f.  V.  about  as  long  as  broad,  constriction 
deep,  linear ;  segments  quadrilateral,  ends 
straight,  angles  rounded,  rough  all  over 
with  minute  granides ;  e.  v.  twice  as  long 
as  broad,  slightly  inflated  at  the  middle 
and  rounded  at  the  ends.  Sporangium 
orbicular,  smooth.  L.  1-500";  B.  1-540". 
(1.7.)    G.B.,  F.,  U.S.A. 

C.  ccelatum  (Ralfs).  —  Frond  in  f.  v. 
about  as  long  as  broad,  suborbicidar,  con- 
striction deep,  linear;  segments  semioi'- 
bicular,  with  six  broad  crenatures  at  mar- 
gin, rough  at  margin  with  scattered 
pearly  granules,  and  at  the  centre  with 
granules  soinewhat  concentrically  ar- 
ranged ;  e.  V.  twice  as  long  as  broad, 
with  a  broad  inflation  at  each  side.  L. 
1-921"  to  1-581";  B.  1-1024"  to  1-608". 
(n.  26.)     G.B.,  I.,  F. 

C.  ornatum  (Ralfs). — Frond  in  f.  v. 
about  as  long  as  broad,  constriction  deep, 
linear;  segments  semiorbicular  or  sub- 
reniform,  with  a  central  truncate  'pro- 
jection at  the  ends  produced  by  the  con- 
tinuation of  a  central  injlation,  rough 
toivards  the  margins  and  on  the  injlation 
with  pearly  granules ;  e.  v.  with  a  rounded 
lobe  on  each  side.  Sporangium  orbicidar, 
spinous ;  spines  elongated,  dilated  at  the 
base,  and  slightly  divided  at  the  extre- 
mity. L.  1-613";  B.  about  the  same. 
G.B.,  F.,  U.S.A. 

C.  Sportella  (Breb.). — Frond  about  as 
long  as  broad,  constriction  deep,  linear ; 
segments  reniform,  with  a  central  trun- 
cate projection  at  the  ends,  its  angles 
slightly  dilated  and  denticulate,  rough  all 
over  with  scattered  pearly  granules.    F. 

C.  Corbula  (Breb.).  —  Frond  about  as 
long  as  broad,  constriction  deep,  linear ; 
segments  subreniform,  a  central  truncate 
jjrojection  at  the  ends  tvith  its  angles 
slightly  dilated  and  minutely  denticulate; 
furnished  at  the  centre  of  each  segment 
tvith  a  circular  protuberance  bordered  with 
granules,  and  rough  thereon  and  towards 
'the  margins  \%ith  scattered  pearly  gi*a- 
nules.     F. 

C.  com missurale  (Breb.). — Frond  small, 
in  f.  V.  one-third  broader  than  long ; 
constriction  very  deep,  rounded;  seg- 
ments narrow-reniform,  toith  a  central 
somewhat  truncate  projection,  produced  by 
the  continuation  of  the  central  inflation, 
rough  on  the  injlation  and  on  the  extre- 
mities with  somewhat  large  pearly  gra- 


nules ;  e.  V.  three  times  longer  than 
broad,  constricted  between  the  central  in- 
jlation and  the  rounded  extremities.  Spo- 
rangium as  in  C.  ornatum.  L.  1-923" ; 
B.  1-663"  to  1-609".  G.,  B.,  F.  /3 
acutum  (Breb.),  angles  sharper. 

C.  cristatum  (Ralfs).  — Frond  in  f.  v. 
as  long  as  broad,  orbicular,  consti-iction 
deep,  linear ;  segments  semiorbicular, 
margined  by  a  series  of  obtuse  papilla- 
like  pearly  granules,  and  having  at  the 
centre  of  each  a  circular  granulate  infla- 
tion ;  e.  V.  linear,  truncate  at  ends,  with 
a  slight  central  inflation  at  each  side. 
L.  1-700" ;  B.  1-653".     G.B.,  F. 

C.  pluviale  (Breb.  in  lit.  c.  ic). — Frond 
about  one-third  longer  than  broad ;  con- 
striction a  shullotv  ivide  notch ;  segments 
subovate,  gradually  tapering,  ends  round- 
ed, or  broadly  rotundato-truncate,  rough 
all  over  with  minute  granules ;  e.  v. 
elliptic.     F. 

2*  Frond  not  compressed;  central  con- 
striction rarely  a  deep,  never  a  linear, 
incision,  but  merely  the  result  of  the  form 
of  the  contracted  bases  of  the  segments ; 
e.v.  circular,  or,  very  rarely,  compj'essed. 

t  Frond  rough  with  pearly  granules, 
which  give  a  denticulate  appearance 
to  the  outline. 

C.  Colpopelta  (Breb,  in  lit.  c.  specimine). 
— Frond  rather  more  than  twice  as  long 
as  broad ;  constriction  a  shallow  contrac- 
tion ;  segments  somewhat  widening  up- 
wards from  the  base,  oval,  sides  and  ends 
broadly  rounded,  very  minutely  granulate, 
grannies  scattered ;  e.v.  circular.     F. 

C.  cylindricum  (Ralfs). — Frond  minute, 
in  f.  v.,  about  twice  as  long  as  broad ; 
segments  subquadrate,  narrower  at  the 
junction  and  gradually  ividening  upwards, 
ends  truncate,  rough  all  over  with  pearly 
granides  somewhat  arranged  in  lines', 
e.  V.  circidar.  L.  1-588" ;'  B.  1-1060". 
(ill.  16,  e.v.  17. )=Peniu?n  Ralfsii  (Kg.). 
G.B.,  I.,  F. 

C.  striolatum  (Niig.  sp.). — Frond  in  f.v. 
about  twice  as  long  as  broad,  elliptic; 
constriction  a  shallow  rounded  sinus ; 
segments  with  sides  and  ends  broadly 
rounded,  pearly  granules  arranged  in  lines 
and  giving  the  margin  a  crenate  appear- 
ance, except  at  the  central  sinus,  which  is 
smooth.  L.  1-16"';  B.  1-33'".  =  Dy- 
sphinctium  striolatum  (Nag.  ).•     G. 

C.  orbiculatum  (Ralfs).— Frond  minute, 
in  f.  v.,  twice  as  long  as  broad ;  constric- 
tion deep;  segments  spherical,  rough  all 
over,  except  at  the  neck-like  contrac- 
i  tion,  with  pearly  granules ;  e.  v.  circular. 


OF  THE  DESMIDlEiE. 


735 


Sporangium  orbicular,  spinous ;  spines 
short,  stout,  conical.  L.  1-498"  to  1-454" ; 
B.  1-7 50".  =Penium  orhicuJatum  (Kg.). 
Ct.B.,  f. 

2 1  Frond  smooth. 

C.  moniUforme  (Ralfs).  —  Frond  mi- 
nute, in  f.  V.  twice  as  long  as  broad ; 
constriction  deep  ;  segments  spherical, 
smooth ;  e.  v.  circular.  L.  1-617" ;  B. 
1-1131".  =  Tessarthroma  monilifonnis 
(Turp.),  Tessarthra  tnoniUformis  (Ehr.). 
G.B.,  I.,  F.,  G. 

C.  connatum  (Breb.).  —  Frond  large, 
in  f.  V.  about  one-half  longer  than  broad ; 
constriction  shallow ;  segments  about  two- 
thirds  of  a  circle,  coa^vsely  pimctate,  and 
with  a  distinct,  sometimes  striated,  bor- 
der; e.v.  circidar.  L.  1-285";  B.  1-1155". 
=  Dysphinctium  Meneghinianum  (Nag.). 
G.B.,  F.,  U.S.A. 

C.  Cucurbita  (Breb.).  — Frond  in  f.  v. 
about  tAvice  as  long  as  broad ;  constric- 
tion a  shallow  groove ;  segments  sub- 
cylindrical,  or  somewhat  oval,  with 
rounded  ends ;  e.  v.  circular ;  e.  f.  punc- 
tate, the  2^iinctxi  scattered.  L.  1-586"  ; 
B.  1-1155".  =Pewmw  clandestinum  (Kg.). 
G.B.,  I.,  F.,  G. 

C.  Talangula  (Breb.). — Frond  in  f.  v. 
about  two  and  a  half  times  as  long  as 
broad ;  constriction  a  shallow  groove  ; 
segments  cylindrical ;  ends  obtuse ;  e.  v. 
circular  ;  e.  f.  minutely  punctate,  the 
puncta  arranged  in  transverse  lines.     F. 

C.  ?  cruciferum  (De  Barj). — Frond 
minute,  in  f.  v.  about  tmce  as  long  as 
broad ;  constriction  an  extremely  shallow 
groove;  segments  subcylindrical ;  ends 
broadly  rounded ;  endochrome  composed 
of  four  broad  plates  cutting  each  other  at 
right  angles ;  e.  v.  cii'cular,  endochrome 
cruciform)  e.  f.  not  punctate.  L.  1-143'"; 
B.  1-287"'.     G. 

C.  Thwaitesii  (Balfs). — Frond  in  f.  v. 
two  or  three  times  longer  than  broad; 
constriction  a  very  shallow  groove ;  seg- 
ments subcylindrical,  with  rounded  ends ; 


endochrome  scattered ;  e.  v.  circular,  or 
very  slightly  compressed;  e.f.  not  punctate, 
or  puncta  very  indistinct.  L.  1-357"; 
B.  1-801".  =  Penium  crassiusculum  (De 
Bary)  ?     G.B.,  F.,  G.,  U.S.A. 

C.  curtum  (Breb.).  —  Frond  in  f.  v. 
rather  more  than  twice  as  long  as  broad ; 
constriction  very  shallow;  segments  at- 
tenuated  and  rounded  at  ends ;  endochrome 
in  fillets ;  e.  v.  circular,  endochrome  ra- 
diate. L.  1-465"  ;  B,  1-1064".  =  Penium 
curtum  (Breb.,  Kg.),  Dysphinctium  Pege- 
lianum  (Nag.)  ?     G.B.,  F.,  G. 

C.  attenuatum  (Breb.). — Frond  in  f.  v. 
fusiform,  three,  or  sometimes  four,  times 
longer  than  broad  ;  constriction  very 
shallow ;  segments  coniccd,  rapidly  at- 
tenuated,  ends  angular,  obtuse ;  e.  v.  cir- 
cular ;  e.  f.  punctate.  L.  1-420" ;  B. 
1-1099"  to  1-1068".    G.B.,  F. 

C.  parvulum  (Breb.). — Frond  minute, 
in  f.  V.  ovato -elliptic,  about  one  and  a 
half  times  longer  than  broad ;  central 
constriction  a  very  shallow  groove ;  seg- 
ments tapering,  ends  broadly  rotundato- 
truncate ;  e.  f.  7iot  punctate.     F. 

C.  turgidum  (Breb.).  —  Frond  very 
large,  in  f.  v.  oval,  turgid,  rather  more 
than  twice  as  long  as  broad  ;  constriction 
a  shallow  sinus ;  segments  somewhat 
tapering,  broadly  rounded ;  e.  v.  circular ; 
e.  f.  pimctate.  L.  1-126";  B.  1-249". 
=  Pleurotcenium  turqidum  (De  Bary). 
G.B.,F.,G.  ^  ^^ 

0.  De  Baryi  (nobis).  — Frond  in  f.  v. 
about  twice  as  long  as  broad ;  constric- 
tion a  ivide  shallow  notch  ;  segments 
cylindrical,  with  broadly  rounded  ends ; 
endochrome  arranged  in  parietal  itidented 
bands ;  e.  v.  cu-cular ;  e.  f.  minutely  punc- 
tate or  pimcta  absent.  =  Pleurotcenium 
Cosmarioides  (De  Baiy).     G. 

With  gi'eat  deference,  we  place  the 
above  species  here,  as  described  by 
M.  de  Bary,  coinciding  with  M.  de  Bre- 
bisson  in  thinking  the  disposition  of  the 
endochrome  not  sufficiently  constant  to 
form  the  genus  Pleiu'otaenium. 


Genus  XANTHIDIUM  (Ehr.).  —  Frond  deeply  constricted  ;  segments 
broader  than  long,  compressed,  entire,  spinous,  having  a  circidar,  cylindrical 
or  conical  projection  on  hath  surfaces  near  the  centre,  which  is  tuberculated  or 
dentate,  or  entii'e ;  end  \iew  elliptic. 

nated  by  three  or  four  diverging  points ; 
central  projections  cylindrical,  trimcate, 
the  border  dentate ;  e.  f.  punctate.  "  Spo- 
rangium large,  orbicular,  with  depressed 


*  Spines  divided  at  the  apex. 

Xanthidium  armatum  (Breb.).  — 
Frond  large,  in  f.  v.  twice  as  long  as 
broad ;  constriction  deep,  linear  ;  seg- 
ments broadest  at  the  base ;  ends  rounded 
or  somewhat  truncate ;  sptines  in  jjairs, 
principaUy  marginal,  short,  stout,  termi- 


tubercles ;  perhaps  immature  "  (Ralfs). 
L.  1-180";  B.  1-270".  (i.  27,  28.)  = 
Zygoxanthium  Echinus  (Kg.).  G.B.,  I., 
F.,  G.,  U.S.A. 


736 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


X.  (?)  Artiscon  (Ehr.). — Frond  in  f.  v. 
about  as  long  as  broad  ;  constriction 
forming  a  wide  notch ;  segments  narrowed 
at  the  base,  with  broadly  rounded  ends ; 
spines  numerous,  restricted  to  the  outer 
margin,  scattered,  eloncfaie,  stout,  termi- 
nated by  three  or  fom*  diverging  points. 
— Asteroxantliium  Arctiscon  (Kg.)*     Gr- 

2  *  Spines  subulate. 

X.  acideatum  (Ehr.).  —  Frond  in  f.  v. 
broader  than  long;  constriction  deep, 
linear ;  segments  somewhat  reniform ; 
spines  subulate,  short,  scattered,  chiejiy 
marginal ;  central  protuberance  cylin- 
drical, truncate,  border  minutely  dentate. 
L.  (not  including  spines)  1-380" ;  B. 
1-1347"  to  1-393".  =  Zygoxanthium 
acideatum  (Kg.).     G.B.,  I.,  F.,  Italy,  G. 

X.  Brebissonii  (Ralfs). — Frond  in  f.  v. 
broader  than  long ;  constriction  deep, 
acute,  not  linear;  segments  subelliptic, 
sometimes  irregular ;  spines  subulate, 
geminate,  marginal ;  central  protuberance 
'cylindrical,  truncate,  border  minutely 
dentate.  L.  (not  including  spines)  1  -416" ; 
B,  1-408"  to  1-365".  =  X.  bisenarium 
(Ehr.),  Zygoxanthium  aculeatum  (Kg.). 
^,  segments  broader  and  more  irregular, 
spines  somewhat  irregular  and  unequal. 
G.B.,  I.,  F.,  G.,  U.S.A. 

X.  fascieulatum  (Ehr.). — Frond  about 
as  long  as  broad  ;  constriction  deep, 
linear;  segments  somewhat  renifortn  or 
subhexagonal,  twice  as  broad  as  long ; 
spines  slender,  subulate,  geminate,  mar- 
ginal, in  four  or  six  pairs ;  central  pro- 
tuberance short,  conical,  somewhat  trun- 
cate, a,  segts.  with  four  pairs  of  spines. 
=  X  antilopmnn  (Br«5b.),  X.  polygonum 
(Hass.,  Breb.).  L.  (not  including  spines) 


1-454"  to  1-350";  B.  432"  to  408".  /3, 
segts.  -v^dth  six  pairs  of  spines. =X  fasci- 
eulatum, var.  polygonum  (Ehr.),  X  fas- 
cieulatum (Hass.,  Breb.).  L.  1-481"  ; 
B.  1-516".    G.B.,  I.,  F.,  G.,  Italy,  U.S.A. 

X.  cristatum  (Breb.). — Frond  rather 
longer  than  broad ;  constriction  deep, 
linear ;  segments  subreniform,  or  truncate 
at  ends ;  spines  straight  or  curved,  subu- 
late, marginal,  one  at  each  side,  at  the 
base  of  the  segment,  solitary,  the  others 
geminate,  in  four  pairs;  central  protu- 
berance short,  conical,  a,  segis.  reni- 
form, spines  scarcely  cmn^ed.  L.  (not 
including  spines)  1-357";  B.  1-499". 
(ii.  18  &  23.)  /3,  segments  truncate  at 
ends,  spmes  micinate.  L.  1-469";  B. 
1-625".     G.B.,  L,  F.,  U.S.A. 

X.  Smithii  (Archer). — Frond  minute, 
in  f.  V.  about  as  long  as  broad ;  constric- 
tion ^a  wide  notch ;  segments  twice  as 
broad  as  long,  trapezoid,  lower  margin 
somewhat  convex,  sides  narrowing  up- 
wards and  straight,  ends  broad  and 
straight,  angles  roimded,  each  of  the  four 
angles  presenting  a  pair  of  sometvhat 
divergent,  short,  minute,  acute  spines ;  s.  v. 
constriction  shallow,  obtuse ;  segments 
with  rounded  sides,  ends  trimcate,  each 
upper  angle  furnished  with  a  minute  spine, 
beneath  each  of  which,  about   half  way 


all  the  spines  somewhat  divergent ;  e.  v. 
subelliptic,  or  broadly  fusiform,  ends 
blunt,  rounded,  furnished  with  three  mi- 
nute spines,  none  oi  the  sides ;  central 
protuberance  a  minute  tubercle,  apparent 
always  in  this  view,  but  in  s.  v.  some- 
times hidden  by  the  projecting  centi'al 
spines.     L.  1-1166" ;  B.  1-1272".     G.B. 


Genus  AETHRODESMUS  (Ehi\).— Frond  deeply  constricted  ;  segments 
compressed,  either  with  four  prominent  angles  and  a  single  or  geminate  spine, 
or  a  tooth,  at  each  angle,  or  having  one  spine  or  acute  tooth  only,  on  each  side, 
at  each  upper  or  outer  extremit}^ ;  without  a  central  projection ;  e.  v.  elliptic 
or  fusiform. 


*  Segments  tvith  four  prominent  angles 
and  a  simple  or  geminate  spine,  or  an 
acute  tooth,  at  each  angle. 

Arthhodesmus  octocornis  (Ehr., 
Hass.,  Breb.). — Frond  smooth,  minute, 
about  as  long  as  broad;  constriction  a 
wide  notch ;  segments  much  compressed, 
trapezoid,  each  angle  terminated  by  one 
or  two  straight,  subulate,  acute  sj^ines,  the 
intervals  between  the  angles  concave. 
a,  spine  solitarv  at  each  angle.  L. 
1-1351";  B.  l-Io38".    (i.  30.)     ^larger, 


spines  geminate  at  each  angle.  L. 
1-1020" ;  B.  1-906".  (i.  29.)  =  Micra- 
sterias  octocornis  (Menegh.,  Kg.),  Xan- 
thidium  octocorne  (Ehr.,  Ralfs).  G.B., 
I.,  F.,  G.,  Italy,  U.S.A. 

A.  bijidus  (Breb.).  —  Frond  smooth, 
very  minute,  about  as  broad  as  long: 
segments  soineivhat  arcuate,  inner  margin 
convex,  outer  concave,  extremities  diver- 
gent, emarginate,  each  angle  terminating 
in  an  acute  tooth ;  e.  v.  comj)ressed,  fusi- 
form, with  a  short  acute  spine  or  tooth 
at  each  end.     F. 


OF  THE  DESMIDIE^. 


737 


2  *  Segments  ivitli  a  single  acute  tooth  or 
spine  at  each  side, 

A.  minufus  (Kg.).  —  Frond  very  mi- 
nute, smooth,  two  or  three  times  longer 
than  broad ;  constiiction  a  minute  acute 
notch ;  segments  narroiv,  lateral  margins 
parallel,  ends  roimdly  concave,  ano-les 
slightly  produced  into  minute  spines 
dii'ected  upwards.     F.,  G. 

A.  Pittacium  (Breb.  sp.). — Frond  mi- 
nute, smooth,  two  or  three  times  longer 
than  broad ;  constriction  a  minute  acute 
notch ;  segments  very  slightly  injlated  at 
the  base,  sides  curved,  end  margin  roundly 
concave,  angles  acute.  =  Euastrum  Pit- 
tacium (Breb.).     F. 

A.  Incus  (Hass.).  —  Frond  minute, 
smooth,  as  long  as  or  longer  than  broad ; 
constriction  a  deep  notch  or  sinus ;  seg- 
ments mth  inner  margin  turgid,  outer 
truncate,  spines  subulate,  acute.  Sporan- 


gium orbicular,  spinous ;  spines  subulate. 
G.B.,  I.,  F.,  G.,  U.S.A.     a,  segments 
somewhat   semiorbicular,    connected  by 
a  distinct   neck,    spines  diverging.     L. 
i  1-1100"    to    1-1660" ;     B.  1-1960"    to 
1-1420".     ^3,  segments  gibbous  near  the 
base,  spines  parallel  or  converging,   (ni. 
\  36.)     L.  1-833"  ;  B.  1-1116". 
j      A.  subulatus  (Kg.). — Frond  minute, 
!  smooth,  about  as  long  as  broad;  con- 
[  striction    a  wide    acute-angled   notch ; 
segments  hroadly  fusiform,  spines  hori- 
zontal, straight,  slender,  subulate;  ends 
convex.     G.,  U.S.A. 

A.  convergens  (Ehr.). — Frond  smooth, 
broader  than  long ;  constriction  deep, 
I  acute ;  segments  elliptic,  each  having  its 
lateral  spines  curved  towards  those  of  the 
'  other;  ends  convex.  L.  1-1539"  to  1-598"; 
j  B.  1-1477"  to  1-584:" .■=  Staurastrum  con- 
,  vergens  (Menegh.),  Euastrum  convei'gens 
\  (Nkg.).     G.B.,  L,  R,  G.,  U.S.A. 


Genus  STAUE.ASTRUM  (Meyen). — Frond  more  or  less  deeply  constricted 
at  the  middle ;  segments  broader  than  long,  often  provided  with  spines  or 
processes ;  end  view  angular  or  radiate,  or  circular  luith  a  lohato-radiate 
margin,  or  very  rarely  compressed  with  a  process  at  each  extremity. 


*  Segrnents  inf.  v.  with  each  of  the  oppo- 
site lateral  extremities  furnished  ivith  a 
mucro  or  a  simple  subulate  acute  awn 
or  spine,  ivhich  in  e.  v.  terminates  the 
angles,  and  without  others  intermediate. 

t  Segments  smooth,  angles  in  e.  v. 
inflated,  sides  concave. 

Staueastruim  dejectum  (Breb.). — Seg- 
ments in  f.  V.  lunate  or  elliptic,  smooth, 
mucrones  or  awns  directed  upwards,  pa- 
rallel or  convergent ;  e.  v.  with  three  or 
four  angles,  angles  injlated,  mammillate, 
terminated  by  a  mucro  or  awn,  sides 
concave  at  the  centre.  Sporangium  or- 
bicular, at  first  covered  with  minute  hair- 
like spines,  afterwards  beset  with  stout 
subulate  spines,  and  placed  between  the 
deciduous  empty  fronds.  L.  1-833" ;  B. 
1-757".=  Goniocystis  (Trigonocystis)  mu- 
cronata  (Hass.).  a,  segments  externally 
lunate,  awns  directed  outwards  ;  /S,  seg- 
ments elliptic,  awns  parallel ;  y,  awns 
converging.     G.B.,  I.,  F.,  U.S.A. 

S.  apiculatum  (Breb.). — Segments  in 
f.  V.  somewhat  turbinate,  smooth,  oppo- 
site lateral  extremities  rounded,  external 
margin  straight,  furnished  at  each  side  on 
the  upper  outer  margin  7iear  the  lateral 
extremities  with  a  simple,  short,  subulate, 
acute  spine  directed  upwards ;  e.  v.  with 
three  angles,  angles  inflated,  mammillate, 
terminated  by  a  short  acute  spine,  sides 


concave.  Sporangium  orbicular,  beset 
with  conical  spines,  enlarged  at  the  base 
and  obtuse  at  the  apex.     F. 

S.  Dickiei  (Ralfs). — Segments  in  f.  v. 
subelliptic,  turgid,  smooth ;  spines  short, 
curved,  acute,  converging  with  those  of 
the  opposite  segment;  e.  v.  with  three 
angles,  angles  injlated,  roimded,  termi- 
nated by  a  spine,  sides  concave  at  the 
centre.  L.  1-855" ;  B.  1-929".   G.B.,I.,F. 
j     S.  brevispina  (Breb.). — Segments  in  f.  v. 
I  elliptic  or  somewhat  reniform,  very  tur- 
,  gid,  smooth ;  mucrones  minute,  iticonspi- 
cuous;   e.  v.   with  three   angles,  angles 
inflated,  broadly  rounded,  terminated  by 
an  inconspicuous  mucro,  sides  concave  at 
the  centre.    L.  1-502" ;  B.  1-510".   G.B., 
L,  F. 

S.  cuspulntum  (Breb.). — Segments  in 
f  V.  fusiform,  or  truncate  on  outer  mar- 
gin, connected  by  a   long  narrow   bandy 
smooth  ;  awns  subulate,  straight,  acute, 
parallel  or  somewhat  converging ;  e.  v. 
with  three  or  four  angles,  angles  inflated, 
mammillate,  terminated  by  an  awn,  sides 
j  concave  at  the  centre.     Sporangium  or- 
I  bicular,  covered  all  over  by  the  enlarged 
!  bases  of  the  few  spines,  which  are  iilti- 
I  mately  much  attenuated  and  acute.     L. 
I  1-883" ;  B.  1-1000".    (i.  31-34.)  =  Phijc- 
I  astrum  cuspidatum  (Kg.),  P.  spinulosum 

(Niig.).     G.B.,  I.,  F.,  G.,  Italy. 
I      S.    aristiferum   (Ralfs).  —  Segments 
3  B 


'38 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA . 


smooth,  iu  f.  v.  prolonged  at  each  lateral 
extrejuity  into  a  mammillate  projection, 
which  is  terminated  by  a  subulate,  acute, 
straight  awn,  the  awns  divergent ;  e.  v. 
with  three  or  four  angles ;  angles  inflated, 
mammillate,  terminated  by  an  awn,  sides 
deeply  concave  at  the  centre.  L.  1-657  "j 
B.  1-1064".     G.B.,  F.,  U.S.A. 

2  t  Segments  smooth,  angles  in  e.  v.  not 

inflated^  sides  straight,  or  nearly  so. 

S.  O'Mearii  (Archer).  —  Segments 
smooth,  in  f.  v.  somewhat  cuneiform, 
gradually  tvidening  upivards,  outer  margin 
truncate,  a's\-iis  acute,  divergent  j  e.  v.  with 
three  or  four  acute  angles  terminated  by 
an  awn,  sides  straight.  Sporangium  orbi- 
cular, spinous ;  spines  subulate,  acute, 
ultimately  somewhat  inflated  at  the  base. 
a,  e.  V.  with  fom*  angles,  awns  compa- 
ratively short.  L.  1-1866";  B.  1-2500". 
/3,  e.  V.  with  three  angles,  awns  longer. 
L.  1-1750" ;  B.  1-2300".     I. 

S.  minus  (Kg.).  —  Segments  smooth, 
very  minute,  in  e.  v.  with^re  angles,  each 
terminated  by  a  very  minute  acute  spine ; 
sides  sti-aight.     G. 

S.  glahrum  (Kg.)- — Segments  smooth, 
in  f.  V.  cuneate,  ends  concave  or  straight, 
spines  slender,  mucro-like;  e. v.  with  three 
mucronate  angles,  sides  concave.     I.,  G. 

3t  Segments  rough  with  minute 
granules. 

S.  lunatum  (Ralfs). — Segments  in  f.  y. 
externally  lunate,  the  inner  margins  con- 
vex, the  outer  somewhat  tnmcate,  and 
rough  with  minute  granules;  spines  subu- 
late, acute,  curved,  obliquely  directed  out- 
wards  and  upwards ;  e.  v.  with  three  in- 
flated romided  angles,  terminated  by  a 
spine,  sides  concave  at  the  centre.  L. 
1-856";  B.  1-686".     G.B. 

S.  granulosum  (Ralfs). — Segments  in 
f.  v.  broadly  fusiform,  granulate,  lateral 
extremities  pointed,  mucronate]  e.  v.  with 
three  subacute  mucronate  angles,  sides 
conyex.  =  Desinidium  granulosum  (Ehr.), 
"  S.  acutmu  (Breb.).     F.,  G. 

2  *  Segments  hi  f.  v.  with  each  of  the  op- 
posite latei'al  extremities  furnished  with 
a  mucro  or  a  simple  subulate  s^nne, 
which  in  end  vieiv  tei'minates  the  angles, 
and  is  accompanied  by  others  interme- 
diate of  a  similar  character. 

S.  pungem  (Br^b.). — Segments  in  f.  y. 
externally  lunate,  the  inner  margin 
curved,  the  outer  tnmcate,  smooth  ;  the 
lateral  marginal  spines  subulate,  curved, 
directed  obliquely  outwards  and  upwards, 


with  six  other  spines  on  the  outer  margin, 
also  directed  outwards ;  e.  v.  with  three 
angles,  each  terminated  by  a  spine,  and 
with  two  others  at  its  base  on  the  upper 
surface,  and  divergent  at  opposite  sides, 
sides  nearly  straight  or  slightly  convex. 
G.B.,  F.,  U.S.A. 

S.  cristatum  (Nag.  sp.). — Segments  in 
f.  V.  broadly  elliptic,  inner  margin  some- 
what more  tm-gid  than  the  outer,  sub- 
mammillate  at  each  side,  terminated  by  a 
mucro  or  short  sjnne,  and  possessing  on  the 
outer  margin  a  fete  others  directed  towards 
the  angles:  e.v.  with  three  subacute  mu- 
cronate angles ;  sides  convex,  with  an  in- 
wardly curved,  submargmal,  single  series 
of  short  mucro-like  spines  directed  to- 
wards the  angles,  sometimes  wanting 
near  the  middle.  L.  1-540" ;  B.  1-543". 
=  Phycastrum  (Pachy actinium)  cristatum 
(Nag.),  Staurastrum  nitidum  (Ai'cher). 
I.,G. 

3  *  Segments  with  each  of  the  opposite 

lateral  extremities  furnished  with  a  bifid 

or  forked  spine,  its  subdivisions  subulate, 

acute,  in  e.  v.   terminating  the   angles, 

and  appearing  as  a  mucro-like  spine, 

with  or  without  intermediate  sjjines. 

S.  Avicula  (Breb.). — Segments  in  f.  v. 

triangular    or    cimeate,    ends    truncate, 

smooth,  vdth  a  single  forked  spine  on 

each  side ;  e.  v.  with  three  inflated  angles, 

the  bifid  spine  appearing  as  a  mucro,  sides 

concave.   L.  1-967";  B.  1-948".  (in.  18, 

e.v.  19.)     G.B.,  F. 

S.  denticulatum  (Nag.  sp.). — Segments 
in  f.  V.  subelliptic,  inner  margin  some- 
what more  turgid  than  the  outer,  both 
undulate  or  toothed  in  a  scolloped  manner, 
with  a7i  unequally  forked  or  getninate 
spine  on  each  side,  the  iqjper  longer  than 
the  loiver,  the  lateral  jjrojections  having  a 
series  of  transvei'se  rows  of  minute  gra- 
nules; e.  V.  with  three  subacute  angles, 
the  spine  appearing  as  a  mucro,  sides 
slightly  concave  at  the  centre,  the  mar- 
gin toothed  as  mentioned  before.  "L. 
1-70"';  thickness  1-55'".''= Phycastrum 
denticulatum  (Nag.).     G. 

S.  armigerum  (Breb.). — Segments  in 
f.  V.  turgid  on  inner  margin,  outer  trun- 
cate, smooth,  with  a  forked  spine  on  each 
side,  and  a  few  simjjle  or  forked,  sometimes 
minute,  spines  disposed  at  equal  ititervals 
bettveen,  on  the  outer  margin ;  e.  v.  with 
three  angles,  the  bifid  spine  appearing  as 
a  mucro,  and  the  intermediate  spines 
projecting  on  each  side.  Sporangium  or- 
bicular, spines  numerous,  elongate,  sub- 
linear,  forked  at  the  apex.  =  S.  spinosum 
(Ralfs).     G.B.,  I.,  F. 


OF  THE  DESMIDIE^. 


^39 


S.  monticidomm  (Breb.).  —  Segments 
in  f.  V.  broadly  elliptic,  smooth,  wdtb  a 
forked  spine  on  each  side,  and  at  the  end 
six  stout  conical  projections  directed  up- 
wards, each  terminated  hij  an  acute  spine ; 
e.  V.  ynth  three  or  four  acute  angles,  sides 
concave,  the  ter mined,  projections  extend- 
ing on  each  side,  confiuent  at  their  bases, 
from  beneath  which  a  mimde,  subulate, 
spine-like  projection  arises  between  them 
and  each  angle.  L.  1-500" ;  B.  1-700". 
r=.Stephanoxanthi^im  monticulosum  (Kg.). 
G.B.,  L,  F. 

S.  Ehrenbergianum. — The  longitudinal 
outline  of  the  segments  obliquely  oval, 
the  inner  margin  convex,  diverging,  the 
outer  margin  very  convex  and  broadly 
truncate  at  the  ends ;  the  sides  in  e.  v. 
slightly  undulate,  membrane  smooth, 
having  at  each  angle  a  large  spine,  di- 
vided to  the  middle,  consisting  of  two 
legs,  and  on  the  terminal  surface  three 
pairs  of  such  spines,  and  between  each 
of  them  and  the  angles  a  pair  of  smaller 
simpler  spines.  =  Phycastrum  Ehrenber- 
giamwi  (^ag.).  "L.  1-66'";  thickness 
1-70'"."  We  have  not  seen  a  dra^ving 
of  the  above  species,  and  give  the  above 
description  following  as  nearly  as  pos- 
sible Nageli's  own  words,  inserting  it 
here  as  most  probably  its  most  fitting 
place. 


4*  Segments  with  numerous  simple  acute 
spines,  in  f,  v.  no  one  in  particular  ter- 
minating the  opposite  lateral  extretnities ; 
e.  v.  angles  etitire,  rounded,  the  spines 
scattered. 

S.  hirsutum  (Breb.). — Segments  in  f.v. 
semiorhicular,  separated  by  a  linear  con- 
striction, covered  with  very  minute,  very 
numerous,  close-set  hair-like  spines ;  e.  v. 
with  three  broadly  rounded  angles,  the 
spines  evenly  and  numerously  scattered ; 
sides  slightly  convex.  Sporangium  or- 
bicular, beset  with  short  spines,  branched 
at  the  apex.  L.  1-676"  to  1-468" ;  B. 
1-833"  to  1-Q80" .  =X.anthidimn  hirsutu?n 
(Ehr.,  Kg.),  Gonioeystis  (Trigonocystis) 
muricata  (Hass.).     G.B.,  I.,  F.,  U.S.A. 

S.  pilosum  (Nag.  sp.). — Segments  in 
f.  V.  obliquely  elliptic,  slightly  divergent, 
the  outer  margin  more  tm-gid  than  the 
inner;  e.  v.  with  three  rounded  angles, 
sides  concave ;  scattered  all  over,  except  a 
small  space  at  the  centre,  with  extremely 
fine  hair-like  spines,  mimdely  capitcde  cd 
their  extremities;  smface  between  the 
spines  smooth.  '' L.  1-55"';  thickness 
1-66'"."  Phycastrum  pilosum  i^i.^.).    M. 


de  Brebisson  is  disposed  to  doubt  the 
accm-acy  of  Nageli's  drawing  {Einzell 
Alg.  8  A.  fig.  4),  the  spines  are  indeed 
so  very  curious. 

S.  Brebissonii  (nobis). — Segments  in 
f.  V.  ovato-lanceolate,  the  lateral  extre- 
mities rounded  and  famished  thereon 
with  numerous  short,  close-set,  hair-like 
spines,  otherwise  smooth ;  e.  v.  with  three 
broadly  roimded  angles,  the  spines  eon- 
fined  to  the  extremities,  sides  concave.  = 
S.  pilosum  (Breb.).  F.  We  are  obliged 
to  alter  the  specific  name  of  this  species, 
— pilosmn  having  been  employed  by  Na- 
geli  before  for  the  preceding  species. 

S.  erosum  (Breb). — Segments  in  f.  v. 
elliptic,  the  lateral  extremities  furnished 
with  numerous  extremely  short  acute 
sjjines,  sometimes  inconspicuous,  sur- 
face granulated  all  over;  e.  v.  with  three 
broadly  rounded  angles,  the  spines  con- 
fined to  the  angles,  sides  concave.     F. 

S.  echinatum  (Breb.).  —  Segments  in 
f.  V.  elliptic,  fm-nished  with  manerous 
sjiines,  somewhat  broad  at  their  base,  ex- 
ceedingly acute,  chiefly  confined  to  the  outer 
margin ;  e.  v.  with  three  angles ;  angles 
and  sides  broadly  rounded,  bordered  all 
round  by  the  spines.     F. 

S.  tcliferum  (Ralfs). — Segments  in  f.v. 
elliptic  or  subreniform,  furnished  with  a 
few  scattered,  elongate,  subulate,  acute 
spines ;  e.  v.  with  three  broadly  rounded 
angles,  the  sjnnes  scattered,  chiefly  con- 
fined to  the  extremities,  surface  between 
the  spines  smooth,  sides  concave.  Spo- 
rangium orbicular,  beset  with  numerous 
elongate  linear  spines,  forked  at  the  apex. 
L.  1-597";  B.  1-643".  (m,  20,  e.  v.  21.) 
G.B.,  I.,  F. 

S.  Hystrix  (Ralfs).  —  Segments  in 
f.  V.  subquadrate,  extremities  somewhat 
rounded,  end  ynargin  nearly  straight,  fur- 
nished with  a  few  scattered,  subulate, 
acute  spines,  chiefly  confined  to  the  late- 
ral extremities ;  e.  v.  with  three  or  four 
broadly  rounded  angles,  the  spines  scat- 
tered, chiefly  confined  to  the  extremities, 
sides  concave.  L.  1-1075"  to  1-1020" ; 
B.  1-1165"  to  1-954".     G.B. 

5  *  Segments  ivith  numerous  short,  trun- 
cate, emarginate,  scattered  spines,  prin- 
cipally confined  to  the  margins;  e.v. 
angles  rounded;  if  angles  spinous,  no 
sjjine  in  particidar  conspicuously  larger 
than  the  others  terminating  the  angles. 

S.  spongiosum  (Breb.). — Segments  in 
f.v.  sejniorbicular,  furnished  with  scat- 
tered   short,    stoid,    forked    spines,    the 
spines  at  the  lower  basal  angle  of  each 
3b2 


470 


Si:STEMATIC  HISTOKY  OF  THE  INFUSORIA. 


rather  larger  than  the  others ;  e.y.  with 
three  somewhat  rounded  angles,  sides 
convex,  and  bordered  all  round  ivith  the 
spines.  L.  1-506"  to  1-418"  ;  B.  1-523" 
to  1-476".  (hi.  22,  e.  v.  23.)  =  Des7nidmm 
ramostnn  (Ehr.),  Asteroxanthium  ranio- 
smn  (Kg.),  Phycastrum  Griffithsianum 
(Nag.).     G.B.,  i.,  F.,  G.,  U.S.A. 

S.  scabrum  (Breb.). — Segments  in  f.v. 
siibelUptic  or  broadly  fusiform,  very 
rough  or  denticulate  at  the  margin ;  e.v. 
with  three  rounded  denticulate  angles, 
sides  straight,  bordered  by  minute,  short, 
truncate  emarginate  sjjines.     F. 

S.  asperum  (Breb.). — Segments  in  f.v. 
broadly  elliptic,  very  rough,  with  very 
viinute,  short,  truncate  or  forked  spines 
chiefly  confined  to  the  outer  margin; 
e.v.  with  three  rounded  angles,  sides 
straight.  Sporangium  orbicular,  beset 
with  numerous  elongate  spines,  twice 
branched  at  the  apex.  L.  1-555";  B. 
1-615".     G.B.,  I.,  F. 


Segments  without  spines , 
rounded. 

t  Frond  smooth. 


?.r.  angles 


S.  muticum  (Breb.). — Segments  in  f.v. 
elliptic,  smooth,  without  spines  ;  e.v.  with 
three  or  four  broadly  rounded  angles,  sides 
concave.  Sporangium  beset  with  nume- 
rous elongate  somewhat  stout  spines, 
forked  at  the  apex.  L.  1-674":  B. 
1-686".  =  S.  trilobum  (Menegh.),  Phyc- 
astrum muticum  (Kg.),  P.  depressum 
(Niig.).     G.B.,  I.,  F.,  Italy,  U.S.A. 

S.  orbicidare  (Balfs).  —  Segments  in 
f  V.  semiorbicidar,  smooth,  without 
spines  ;  e.  v.  with  three  broadly  rounded 
angles,  sides  slightly  concave.  L. 
1-1037";  B.  1-110)6" .  =  Desmidium  orbi- 
cular e  (Ehr.),  Phycastrum  oi'hiculare 
(Kg.),  Goniocystis  ( Trigonocystis)  orbi- 
cularis (Hass.).  G.B.,  I.,  F.,  G.,  Italv, 
U.S.A. 

S.  coarctatum  (Breb.). — Segments  ob- 
long,  lateral  extremities  rounded,  inner 
margin  convex,  outer  somewhat  concave  at 
the  centre  (inversely  reniform),  smooth  ; 
e.v.  with  three  injlated  rounded  angles, 
sides  concave.     F. 

^.pygmceum  (Breb.). — Segments  in  f.v. 
cuneiform,  outer  margin  slightly  convex, 
smooth ;  e.v.  with  three  blunt  angles, 
sides  slightly  convex.  Sporangium  orbi- 
cular, "  beset  with  protuberances  bearing 
each  two  bifurcate  spines  at  their  sum- 
mits."    F.,  G. 

2t  Segments  having  the  projecting  por- 
tions surrounded  by  annular  transverse 


lines  (rows  of  puncta  or  minute  gra- 
nules ?). 

S.  striolatum  (Nag.  sp.). — Segments 
in  f.  V.  reniform,  divergent,  ends  concave, 
each  of  the  lateral  portions  crossed  by 
about  Jive  transverse  lines  (annular  rows 
of  closely  set  puncta  or  minute  gra- 
nides?);  e.v.  with  three  rounded  angles, 
sides  concave,  each  of  the  projections 
crossed  as  before  by  about  five  transverse 
lines,  the  central  portion  smooth.  L. 
1-100".  =  Phycastrum  striolatum  (Nag.). 

3t  Fronds  rough  superficially  with  scat- 
tered granules.  (Sometimes  S.  tri- 
corne  might  be  thought  almost  to  come 
in  here ;  but  the  extremities  in  that 
species  are  more  prolonged  into  di- 
stinct processes,  usually  colourless, 
and  mostly  divided  at  the  apex.  Here, 
also,  might  S.  asperum  and  S.  scabrum 
seem  to  fall  in  ;  but  they  are  provided 
with  very  short  and  trimcate  spines  on 
some  part  of  their  margin.) 

S.  muricatum  (Breb.). — Segments  suh- 
elliptic,  the  outer  margin  more  turgid 
than  the  inner,  rough  all  over  with 
scattered  conic  granules',  e.v.  with  three 
angles,  both  angles  and  sides  broadly 
rounded.  L.  1-409";  B.  1-47^".  =  Des- 
midium  apiculosuni  (Ehr.),  Xanthidium 
deltoideuni  (Corda),  Phycastrum  ajnculo- 
sum  (Kg.),  P.  muricatum  (Kg.)?  Gonio- 
cystis (Trigonocystis)  muricata,  /3  (Hass.). 
G.B.,  F.,  G.,  Italy. 

S.  punctidatum  (Breb.). — Segments  in 
f.v.  elliptic,  equal,  rough  with  scattered 
j}uncfa-like  granules;  e.v.  with  three 
broadlv  rounded  angles,  sides  concave. 
L.  1-704"  ;  B.  1-881".     G  B.,  I.,  F. 

S.  rugulosum  (Breb.). — Segments  in 
f.v.  broadly  elliptic,  equal,  rough  with 
scattered  granules,  giving  a  denticulate 
appearance  to  the  margin,  especially  at 
the  opposite  lateral  extremities  ;  e.v.  with 
three  broadly  rounded  denticulate  angles, 
sides  straight  or  nearly  so.     F. 

S.  pileolatum  (Breb.). — Segments  in 
f.v.  quadrate,  the  basal  angles  rounded 
and  rough  with  mimde  granules,  sides 
with  a  broad  shallow  sinus,  the  upper 
margin  terminating  in  three  conspicuous, 
large,  rounded,  conical,  very  slightly  di- 
vergent projectiotis,  which  are  rough  with 
minute  granules ;  e.v.  with  three  rounded 
angles,  sides  entire.     F. 

S.  Capitulum  (Breb.). — Segments  in 
f.v.  quadrate,  sides  with  a  rounded  sinus 
at  the  middle,  the  basal  and  upper  angles 
crenated,  rounded,  upper  margin  straight ; 


0¥  THE  DESMIJ)IE^. 


741 


e.v.  with  three  broadly  rounded  crenated 
angles,  sides  nearly  straight,  each  with  a 
slight  shaUoiv  depression  or  constriction  at 
the  middle.     F. 

S.  (dternans  (Breb.). — Segments  in  f. v. 
elliptic  or  oblong,  two  or  three  times 
as  broad  as  long,  separated  by  a  wide 
sinus,  tivisted,  unequal ;  rough  with  very 
minute  pearly  granules ;  e.v.  with  three 
ohtiise  and  rounded  angles,  forming  short 
not  colourless  rays,  alternating  with 
''those  of  the  other  segment,  sides  con- 
cave. L.  1-1037" ;  B.  1-1106';.  (ii.l6,17.) 
=  Goniocystis  (Tri(/onocystis)  hexaceros 
(Hass.),  k  dispar  (Breb.)  ?  G.B.,  I., 
R,  U.S.A. 

S,  dilatatum  (Ehr.).  —  Segments  in 
f.  V.  fusiform,  their  lateral  extremities 
obtuse,  equal,  rough  with  puncta-like 
pearly  granules  j  e.v.  "^dth  four  rotmi' 
dato-truncafe  angles,  forming  short, 
broad,  not  colourless  ravs,  sides  concave. 
L.  1-1201";  B.1-1S81".  ^Phycastrum  di- 
latatum (Kg.),  Goniocystis  (Staurastrum) 
dilatata  (Khss.).  G.B.,  I.,  F.,  G.,  Italy, 
U.S.A. 

S.  cre7iatum  (Bailey). — Segments  in 
f.v.  fan-shaped  in  oidline,  separated  by  a 
wide  rounded  sinus,  inner  margin  concave, 
smooth,  outer  semicircular,  crenate ;  e.v. 
with  three  rotundato-truncate  crenate 
angles,  sides  concave,  smooth.     U.S.A. 

7*  Segments  with  or  without  spines;  in 
f  V.  with  spines  {if  any)  few  and  scat- 
tered; in  e.  V.  angles  emarginate  or 
hijid,  or  truncate  and  the  extremities 
plane  and  quadrangular. 

S.  hifidum  (Ralfs). — Segments  in  f.v. 
.  .  .  .  ;  in  e.v.  with  three  acidely  hijid  or 
emarginate  angles,  the  teeth  acute  ;  sides 
concave.  =  Desmidium  hifidum  (Ehr.), 
Phycastrum  hifidum  (Kg.),  nee  Gonio- 
cystis (S.)  bifida  (Hass.).     F.,  G. 

S.  quadrangidare  (Breb.). — Segments 
in  f.v.  subquadrate,  with  a  few  short 
bifid  or  tooth-like  spines  spreading  later  ally, 
otherwise  smooth  :  e.v.  with  four  tru7i- 


cate  and  emarginate  angles ;  sides  concave. 
L.1-1157";  B.  1-1163".  (in.  24,  e.v.  25.) 
/3,  angles  in  e.v.  broader,  with/o?^r  teeth 
at  the  extremity,  and  tivo  minute  teeth  on 
upper  side  (Breb.).     G.B.,  F. 

S.  Cerberus  (Bailey). — Segments  in  f.v. 
truncato-oblong,  smooth;  the  opposite 
lateral  extremities  abruptly  truncate,  ex- 
ternally  plane  and  quadrangular,  the  an- 
gles drawn  out  into  acute  spine-like  ex- 
tensions or  teeth,  two  projecting  upwards 
and  two  downwards ;  e.v.  with  three 
abruptly  truncate  angles,  extremities  as 


in  f.v.  plane  and  quadrangular,  the  teeth 
at  the  angles  divergent.     U.S.A. 

8*  Segments  ivithout  spines;  in  f.v.  and 
e.v.  the  angles  te^'ininated  by  either  a 
conspicuous  rounded  nipple-like  projec- 
tion, or  an  enlarged  rounded  knob,  or 
an  elongate  cajntate  process. 

S.  tumidum  (Breb.). — Segments  in  f.v' 
elliptic,  turgid,  smooth ;  their  margin 
striated,  and  their  opposite  lateral  ex- 
tremities furnished  with  a  rounded  con- 
spicuous nipple-like  p>rojectio7i ;  e.v.  with 
three  or  fom-  angles,  the  nipple-like  pro- 
jection terminating  the  angles,  sides 
convex  ;  e.  f.  punctate  ;  gelatinous  in- 
vestment very  evident.  L.  1-200"  :  B. 
1-250".  =  /^.  orbiculare  (INIenegh.),  Phyc- 
astrum tumidum  (Kg.).     G.B.,  I.,  F. 

S.  glohulatum  (Breb.).  —  Segments  in 
fv.  fusiform,  capitate;  e.v.  with  three 
angles,  each  enlarged  into  a  rounded 
granulated  knob,  sides  nearly  straight, 
(ill.  26,  e.v.  27.)    F. 

S.  bacillare  (Breb.). — Segments  in  f.v. 
somewhat  arcuate,  each  diver  gent  from  the 
opposite  segment,  somewhat  attenuated, 
Jinally  capitate,  smooth;  e.v.  with  from 
three  to  five  capitate  Y?ijs,.=  Phycastrum 
bacillare  (Kg.).     F. 

9  *  Segmetds  in  fv.  with  the  opposite 
lateral  extremities  each  tapering  into  a 
single  more  or  less  elo7igate  colourless 
process  divided  at  the  apex,  which  in 
e.  V.  terminates  the  angles,  with  or  with- 
out intermediate  simple  or  truncate 
spi?ies. 

t  Segments  smooth. 
S.  brachiatum  (Ralfs). — Segments  in 
f.v.  smooth,  narrow  below,  widening  up- 
wards, ends  truncate,  the  lateral  extre- 
mities each  produced  into  a  smooth,  elon- 
gate, straight,  tapering,  divergent  process, 
bifid  or  trifid  at  the  apex;  e.v.  tri-  or 
quadriradiate,  sides  concave.  L.  1-1111"; 
B.  1-1785".  =  Goniocystis  (S.)  bifida 
(Hass.),  Phycastrum  Ralfsii  (Kg.).  G.B,, 
I.,  F.,  G. 

2t  Segments  rough  \vdth  superficial 
granules,  those  on  the  processes  ar- 
ranged in  transverse  lines.  {S.  poly- 
morphum  has  sometimes  a  few  incon- 
spicuous scattered  spines.) 

S.  tricorne  (Breb.). — Segments  in  f.v. 
somewhat  fusiform,  often  twisted,  rough 
with  minute  puncta-like  granules,  taper- 
ing at  each  side  into  a  short  usually  co- 
lourless process,  blunt,  or  divided  at  the 
apex  ;  e.v.  tri-  or  quadriradiate,  processes 


742 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


I 


short,  usually  coloiu'less,  sides  somewhat 
concave.  Sporangium  orbicular,  beset 
with  spines  ultimately  branched  at  the 
apex.  L.  1-1275"  to  1-972"  ;  B.  1-948" 
to  1-697".  =Desmidium  hexaceros  (Ehr.). 
Phycastrum  tricorne  (Kg.),  P.  trilohatum 
'Kg.)  ?  P.  hexaceros  (Kg.)  ?,  P.  Rcdfsii 
Nag,),  P.  cremdatum  (Nag.  in  part). 
"  B.,  I,  R,  G.,  U.S.A. 

S.  cyrtocerum  (Breb.). — Segments  in 
f.  V.  suhcimeate,  gradually  wddening  up- 
wards, truncate  at  the  end  margin, 
rough  with  minute  granules,  the  lateral 
processes  incurved,  di\dded  at  the  apex ; 
e.v.  triradiate,  processes  short,  cm-ved, 
sides  slightly  concave.  L.  1-800"  ;  B. 
1-500" .  =  Phycastru7n  cyrtocerum  (Kg.). 
G.B.,  I.,  R,  U.S.A. 

S,  injlexum  (Breb.). — Segments  in  f.v. 
broadly  elliptic,  it^ner  and  outer  margin 
turgid,  rough  with  minute  granules, 
lateral  processes  incurved,  short,  divided 
at  the  apex;  e.v.  tri-  or  quadriradiate, 
processes  short,  sides  concave.     F. 

S.  hrachycerum  (Breb.). — Segments  in 
f.v.  ovato-lunate,  inner  margin  turgid, 
outer  equally  rounded,  rough  all  over  with 
minute  granules,  and  on  the  outer  mar- 
gin very  rough  with  minute,  acute,  short, 
almost  spine-like  granules ;  lateral  pro- 
cesses incm^ed,  divided  at  the  apex ; 
e.  V.  triradiate,  processes  short,  straight, 
sides  somewhat  concave.     F. 

S.  pohpnorphum  (Breb.).  —  Segments 
in  f.v.  broadly  elliptic  or  almost  circidar, 
rough  with  minute  gTanules  (sometimes 
with  a  few  minute  scattered  spines), 
processes  short,  stout,  tipped  by  three  or 
four  divergent  spines;  e.v.  with  three, 
fom*,  five,  or  six  angles,  each  produced 
into  a  short  stout  process.  Sporangium 
orbicular,  beset  with  elongate  spines, 
forked  or  branched  at  the  apex.  L. 
1-1000" ;  B.  1-1157".  (ii.  20,  21,  24,  25, 
&  31.)     G.B.,  I.,  R,  U.S.A. 

S.  gracile  (Ralfs). — Segments  in  f.v. 
triangular,  ends  truncate,  rough  Tvdth 
minute  granules,  tapering  at  each  side 
into  elongate,  straight,  slender,  horizontal 
processes,  terminated  by  three  or  four 
minute  spines ;  e.v.  triradiate,  processes 
straight,  sides  concave.  L.  1-773"  to 
1-539";  B.  1-348"  to  1-372".  (m.  28, 
e.v.  29.)  =  Goniocystis  (Trigonocystis) 
gracilis  (Hass.),  Phycastrum  gracile 
(Kg.).     G.B.,L,R 

S.  paradoxum  (Meyen).  —  Segments 
in  f.v.  gradually  icidening  upwards,  the 
ends  truncate,  rough  with  minute  gra- 
nules, processes  straight,  elongate,  slen- 
der, divergent,  trifid  at  the  apex  ;  e.v. 
tri-  or  quadriradiate,  processes  straight, 


sides  straight  or  very  slightly  concave. 
L.  1-941" ;  B.  1-1165".  =  Phycastrum 
paradoximi  (Kg.),  Goniocystis  {S.)  para- 
doxmti  (Hass.).  G.B.,  I.,  F.,  G.,  Italy, 
U.S.A.  ....        J, 

3t  Segments  furnished  with  variously 
disposed  spines,  which  are  either  sim- 
ple, or  short  and  notched  at  the  apex. 

^.ptroboscideum  (Breb.). — Segments  in 
f.v.  broadly  cuneiform,  ends  somewhat 
convex,  rough  with  very  minute,  shortj 
truncate  spines,  chiefly  conflned  to  the 
outer  margin,  processes  short,  thick,  trifid 
at  the  apex  ;  e.  v.  triradiate ;  processes 
short,  stout,  sides  concave.  L.  1-555" ; 
B.  1-500".  =aS'.  «67?m««, /3  (Ralfs,  Breb.). 
G.B.,  I.,  R 

S.  controversu7n  (Breb.). — Segments  in 
f.v.  elliptic  or  broadly  fusiform,  some- 
times irregular,  fm'nished  with  scattered, 
irregular,  simple  or  notched  spines;  pro- 
cesses short,  generally  curved,  spimdose, 
terminated  by  minute  spines ;  e.  v.  tri- 
radiate, the  processes  ttvisted  or  curved. 
Sporangium  orbicular,  spinous ;  spines 
t^dce  branched.  L.  1-972"  ;  B.  1-886". 
Goniocystis  {Trigonocystis?)  aculeatum 
(Hass.).     G.B.,  I.,  F. 

S.  aculeatum  (Menegh.). —  Segments 
in  f.v.  broadly  fusiform,  furnished  with 
thicMy  scattered  simple  or  notched  spines ; 
processes  elongate,  spinulose,  straight,  ter- 
minated by  minute  spines;  e.v.  3-5- 
radiate,  the  processes  straight,  sides  con- 
cave. L.  1-666" ;  B.  1-500"".  =  Desm  idium 
aculeatum  (Eh.),  Phycastrum  aculeatum 
(Kg.),  Goniocystis  {Trigonocystis)  acidea- 
tum  (Hass.).     G.B.,  I.,  R,  G.,  Italy. 

S.  vestitum  (Ralfs). — Segments  in  f  v. 
fusiform,  older  margin  bordered  by  minute 
emarginate  spines ;  processes  elongate, 
rough,  terminated  by  minute  spines; 
e.v.  triradiate,  the  processes  elongate 
straight,  sides  concave,  furnished  at  the 
middle  ivith  a  pair  of  conspicuous  slender 
forked  sp)ines,  sometimes  accompanied  by 
a  few  others  shorter  either  simple  or 
notched.  L.  1-625"  ;  B.  1-384".  (in.  30, 
e.  V.  31.)     G.B.,  I.,  R 

S.  oxyacantha  (Archer). — Segments  in 
f.v.  broadly  fusiform,  rough  with  minute 
granules,  fiu'nished  o)i  the  older  margin 
with  six  subulate  acute  depressed  spines 
(fom-  of  which  are  apparent  in  this  view); 
processes  elongate,  incurved,  the  granides 
thereon  arranged  in  transverse  lines,  ter- 
minated by  three  or  four  minute  spines  ; 
e.  V.  ti'ira&iate,  the  processes  elongate 
straight,  sides  somewhat  concave,  end 
furnished  at  the  middle  with  a  pair  of 
very    slender    extremely    acute    subulate 


OF  THE  DESMIDIEJE. 


743 


spines  projecting  to  each  side.    L.  1-770' ; 
B.  1-580'*'  to  1-636".     I. 

10*  Segments  in  f.v.  with  the  opposite 
lateral  extremities  tei'minating  in  one 
or  ttco  elongate  colourless  2^''oeesses 
mostly  divided  at  the  apex ;  and  in  e.v. 
either  tapering  into  a  single  process  at 
each  angle,  and  furnished  icith  others 
beticeen  or  above  of  a  similar  character 
definite  in  mmiber,  or  the  angles  fur- 
nished with  two  short  processes  side  by 
side  and  unaccompanied  by  others. 

t  Segments  at  end  view  \vitli  tlie  addi- 
tional processes  more  than  one  for  each 
angle^  and  placed  on  the  margin  or 
upper  surface,  and  diverging  laterally. 

S.  furcatum  (Breb.).  —  Segments 
smooth,  in  f  v.  broadly  elliptic,  furnished 
at  each  opposite  lateral  extremity  with  a 
colom-less  bifid  process,  and  with  six 
others  similar  and  divergent  on  external 
margin  (four  only  of  which  are  usually 
\'isible) ;  e.v.  with  three  acute  angles, 
each  tapering  into  a  terminal  process, 
and  each  bearing  two  others  on  the  upper 
surface,  placed  to  each  side,  and  project- 
ing laterally.  L.  1-860";  B.  1-900".= 
Xanthidium  furcatum  (Ehr.),  Astero- 
xanthium  furcatum  (Kg.),  A.  bisenarium 
(Kg.)?    •aB.,L,F. 

S.  senarmm  (Ehr.).  —  Segments 
smooth,  in  e.v.  with  three  angles,  each 
temiinatiug  in  a  short  process  tipped  by 
minute  spines,  and  having  six  other  short 
forked  processes  on  the  margins,  two  at 
each  side  and  projecting  laterally,  and 
six  others  on  the  ujoper  surface,  confluent 
at  their  bases,  divergent  at  their  exti-e- 
mities,  and  forked ;  sides  straight,  (ii.  7.) 
=  Stephanoxanthiiim    se^iarium    (Kg.). 

S.  eiistephanum  (Ehr.).  —  Segments 
gi'anulate,  in  e.v.  with  three  angles,  each 
terminating  in  a  short  process  tipped  by 
minute  spines,  without  latei'al  processes, 
but  %vith  six  others  confluent  at  their 
bases  on  the  upper  sm-face,  divergent  and 
forked,  (ii.  S.)  =  Stephanoxanthium  euste- 
phamnn  (Kg.).     U.S.A. 

S.  Ehrenbergii  (Coy&q). — "  Corpuscles 
par  paire,  vus  de  cote,  ovale  s ;  vus  d'en 
haut,  triangulaires,  munis  de  six  ap- 
pendices terminaux  et  lateraiLx,  et  de 
deux  autres  appendices  centraux,  qui 
sont  coui'ts,  blancs,  en  fomx-hette,  mais  a 
pointes  divergentes  "  (Corda,  '  Obs. 
Micr.  des  Animalcules  de  Carlsbad,' 
1840).  In  Corda's  figure  the  f.  v.  is 
somewhat  like  that  of  S.  furcatum.  The 
segments  are  broadly  fusiform,  the  pro- 


cesses are  aU  very  short  and  stout,  and 
the  bifiu'cations  very  divergent  (formed 
indeed  somewhat  like  the  tail  of  a  Jish). 
=Xanthidium  Ehrenbergii  (Corda,  /.  c). 
S.  ai'ticidatwm  (Corda). — "  Corpuscles 
ovales,  par  paii*e,  munis  aux  deux  bouts 
d\m  appendice  a  deux  cellules,  qui  se 
divise  encore  en  fonue  de  fom-chette,  et 
lateralement  en  deux  appendices  plus 
longs  a  quatre  cellules,  et  une  pointe  en 
fom'chette.  Sur  les  deux  cotes  plats,  se 
trouveut  deux  protuberances  trans- 
versales,  egalement  pom-vues  de  deux 
allongements  cellulau-es  en  fourchette  " 
(Corda,  I.  c).  In  Corda's  figures  the  seg- 
ments in  f.v.  are  elliptic,  the  processes 
stout,  elongate,  transversely  striated  (by 
rows  of  granules?),  bifurcate,  the  bifurca- 
tions recmned.  =  X  urticulatum  (Corda). 
Neither  of  the  figm-es  of  the  foregoing  is 
explanatory ;  both,  however,  seem  to  be 
distinct  species. 

2t  Segments  with  the  additional  pro- 
cesses one  for  each  angle,  and  placed 
on  the  upper  sui-face  immediately 
above  those  terminating  the  angles. 
S.  furcigerum  (Breb.).  —  Segments  in 
f.  V.  twice  as  broad  as  long,  separated  by 
a  deep  constriction,  rough  with  pearly 
granules,  terminating  at  each  side  in  two 
elongate,  stout  processes,  bifid  at  the  apex, 
placed  one  above  the  other,  the  inferior 
horizontal,  the  superior  directed  ob- 
liquely outwards  and  divergent,  both 
having  the  granules  thereon  in  trans- 
verse lines ;  e.  v.  with  three  or  four 
angles,  each  extremity  terminating  in  a 
process  and  having  the  other  immedi- 
ately above  it  on  the  upper  sui-face,  sides 
concave  at  the  centre.  L.  1-333";  B. 
1-357"  inch  processes,  (in.  32,  e.v.  33.) 
—  Bidymocladonfurcigerus  (Ralfs),  Aste- 
roxanthium  furcigetmm  (Kg.),  Xanthi- 
dium coronatum  (Ehr.)  ?,  A.  coronatum 
(Kg.)  ?    G.B.,  I.,  F.,  G.,  U.S.A. 

S.  longispinum  (Bail.  sp.).  —  Segments 
in  f.  V.  triangular,  trimcate  on  outer  mar- 
gin, smooth,  terminating  at  each  side  in 
two  much  elongated  stout  processes,  sub- 
acute at  the  apex,  placed  one  above  the 
other,  divergent ;  e.  v.  with  three  angles, 
each  exti'emity  tenuinated  by  a  process 
and  having  the  other  immediately  above 
it  on  the  upper  surface,  side  straight.  = 
Didymocladon  longispinum  (Bailev). 
U.S.A. 

3t  Segments  with  two  processes  from 
each  angle  placed  side  by  side. 
S.  l(Bve  (Ralfs). — Segments  in  f.  v.  ex- 
ternally lunate  or  somewhat  cuneate,  with 


744 


SYSTEMATIC  HISTORY  OF  THE  rNTUSORIA. 


the  ends  somewhat  protuberant,  smooth, 
terminating  at  each  side  in  a  imir  of 
short  stout  processes  ])lace(l  side  hy  side 
(one  only  of  which,  however,  is  apparent), 
directed  upwards  and  divergent,  forked 


at  the  apex 


with   three  or  four 


angles,  each  terminated  hy  the  pair  of 
short  processes  sejjarated  by  a  rounded 
sinus,  sides  deeplv  concave.  L.  1-1220" ; 
B.  1-2127".     G.B.,  F. 

11  *  Segments  in  f  v.  tvith  each  opposite 
lateral  extremity  terminating  in  a  colour- 
less i^rocess,  either  short,  rounded,  and 
dentate,  or  elongate  and  entire  at  the 
end;  e.v.  circidar,  margined  tvith  from 
Jive  to  seven  processes,  or  compressed, 
and  with  hut  two  processes.  (S.  poly- 
morphum  sometimes  has  Jive  rays,  and 
the  e.  V.  appears  almost  circular,  hut  the 
extremities  of  the  processes  are  not  entire 
hut  tipped  with  minute  spities.^ 

t  End  -vdew  circular. 

S.  sexcostatum  (Breb.). — Segments  in 
f.  V.  suhorhicular,  furnished  on  each  side 
with  a  short,  broad,  truncate,  dentate  pro- 
cess, and  ^dth  slight  crenate  elevations 
on  the  outer  margin ;  e.  v.  circidar,  bor- 
dered by  Jive  or  six  short,  rounded,  den- 
tate, colourless  marginal  rays.  L.  1-661" ; 
B.  1-833"  to  1-694".  =  Goniocijstis  {Pen- 
tasterias)  Jenneri  (Hass.),  Stephanoxan- 
thium  sexcostatujn  (Kg.).     G.B.,  1.,  F. 

S.  margaritaceum  (Menegh).  —  Seg- 
ments in  f.  V.  gradually  widening  up- 
wards, rough  with  pearly  gi'anules,  outer 
margin  convex,  produced  at  each  side 
into  a  colourless,  more  or  less  attenuate 
short  /jrooess,  having  the  granules  in 
transverse  lineS;  blunt  and  entire  at  the 


apex ;  e.  v.  circular,  bordered  by  from 
five  to  seven  short,  narrow,  obtuse,  co- 
lourless, gi'anulate  marginal   raj's.      L. 
1-1176"  ;     B.  J-1000"    inch  _  processes. 
(hi.  84,  e.v.  35.)  =  Pentasterias  marga- 
ritacea  (Ehr.  ),Phycastru}7i  margaritaceum 
(Kg.),   Goniocystis  {Pent.)  margaritacea 
(Hass.),  Phycastrum  rotundatum  (Kg.). 
G.B.,  I.,  F.,  G.,  U.S.A. 
j      S.  Arachne  (Ealfs). — Segments  in  f.  v. 
suhorbicidar,  rough   with    minute    gi-a- 
I  miles,  lower  margin  tm-gid,  outer  convex, 
I  tapeiing  at  each  side  into  an  elongate, 
I  slender,  incurved  process  ha\'ing  the  gra- 
I  miles  thereon  in  transverse  lines,  entire 
at  the  apex ;  e.  v.  circular,  bordered  by 
five   sle?ider,   linear,   colourless   marginal 
rays.     L.  1-1020";  B.  1-652"  incl.  pro- 
cesses. =  Goniocystis (Pe)dasterias)  arach- 
•  nis  (Hass.),  Phycastrum  Arachne  (Kg.), 
'  P.  radiatmn  (Kg.)  ?.     G.B.,  F. 

2 1  End  view  compressed. 

S.  tetracermn  (Ralfs).  —  Segments  in 
f.  V.  gi'adually  widening  upwards,  rough 
with  minute  gi'anules,  outer  margin 
truncate  or  concave,  tapering  at  each 
lateral  extremity  into  an  elongated,  very 
slender,  colourless  process,  ha-vdng  the 
granules  thereon  in  transverse  lines, 
entire  at  the  apex  and  divergent ;  e.  v. 
much  com^jressed,  with  a  process  at  each 
extremity.  L.  1-2703";  B.  1-1785".  = 
S.  paradoxum  (Ehr.),  Goniocystis  (S.  ?) 
paradoxum  (Hass.),  Phi/castrum  parU' 
doxum  (Kg.).     G.B.,  I.,  F.,  G.,  U.S.A. 

[S.  enorme  (Ralfs)  is  omitted,  this 
plant  having  been,  as  we  think,  sho^vu 
by  De  Bary  {op.  cit.)  to  be  a  Poly- 
edrium.] 


2.  Fronds  distinctly,  faintly,  or  not  at  all  constricted  at  the  middle,  very 
rarely  less  than  three  times,  mostly  many  times  longer  than  broad. 
Si)orangia  smooth,  and  either  spherical,  elliptic,  quadi^ate,  or  cruciform. 

Genus  TRIPLOCERAS  (Bailey). — Frond  very  elongate,  straight,  constricted 
at  the  middle ;  segments  with  numerous  whorls  of  knot-like  projections,  ends 
three-lohecl,  lobes  hidentate.  Endochrome  with  a  terminal  rounded  clear  space, 
in  which  are  active  granules. 


Triploceras  verticillatum  (Bailey). 
—  Frond  stout,  sutm^e  prominent,  seg- 
ments about  eight  or  ten  times  longer 
than  broad,  with  numerous  whorls  of 
prominent,  broad,  truncate,  emarginate 
projections,  (in.  37.)  =  Docidium  verti- 
cillatum (Ralfs).     U.S.A. 


T.  gracile  (Bailey).  —  Frond  rather 
slender,  sutiue  prominent,  segments  ten 
or  twelve  times  longer  than  loroad,  with 
nimierous  whorls  of  prominent,  some- 
what triangular,  roundly  blunt  projec- 
tions. =  Docidium  verticillatum  (Ralfs). 
U.S.A. 


Genus  DOCIDIUM  (Breb.). —  Frond  very  elongate,  straight,  constricted  at 
the  middle ;  segments  with  an  inflation  at  the  base  (veiy  rarely  not  so),  often 


or  THE  DESMIDIEJi. 


745 


with  others  above,  or  with  whorls  of  knot-like  projections,  ends  abruptly 
truncate.  Endochrome  with  a  terminal  rounded  clear  space  at  each  end,  in 
which  are  active  granules. 

D.  davatum  (Kg.).  —  Frond  slender ^ 
suture  scarcely  prominent,  segments 
eight  or  ten  times  as  long  as  broad, 
slightly  clavate  near  the  ends,  and  ulti- 
mately somewhat  attenuated,  basal  infla- 
tion sometimes  solitary,  sometimes  hav- 
ing another  slight  one  above  it ;  ends 


verrucosum     (Bailey).  — 
stout,   suture   forming-   a 


DOCLDIUM 

Frond  rather 

rim;  seg-ments  five  or  six  times  longer 


undulations  due  to  so  many  whorls  of 
small  tubercle-like  prominences  j  ends 
entire.     U.S.A. 

D.  nodosum  (Bailey).  —  Frond  stout, 
sutm'e  forming  a  rim ;  segments  three  or 
four  times  as  long  as  broad,  "v%dth  four 
j)ro7m'nent  injlated  nodes,  includifiy  the 
basal,  which  is  somewhat  the  largest, 
and  which  are  due  to  so  many  whorls  of 
knot-like  prominences  or  large  tubercles ; 
ends  entire ;  e.  v.  crenate.     U.S.A. 

D.  coronatum  (Breb.).  —  Frond  stout, 
suture  forming  a  thickened  projecting 
rim ;  segments  fom'  to  six  times  as  long 
as  broad,  tapering,  regularly  inflated  up- 
wards from  the  base,  so  as  to  produce 
an  undulated  margin,  the  basal  inflation 
the  most  prominent,  the  others  less  so, 
and  wanting  towards  the  ends ;  ends 
bordered  by  prominent  tubercles,  projeetiny 
all  round;  e.  v.  circular,  bordered  by  the 
tubercles ;  e.  f  coai'sely  punctate.     F. 

D.  undulatum  (Bailey). — Frond  slender, 
suture  foiTuing  a  minute  rim,  segments 
eight  to  ten  times  as  long  as  broad, 
with  six  or  eight  sinuations  at  regular  in- 
tervals, producing  as  many  inflations 
besides  the  basal,  which  is  not  larger 
than  the  others ;  ends  and  bases  crenate. 
U.S.A. 

D.  JE7irenbergii(Ralfs). — Frond  slender, 
linear;  sutiu'e  forming  a  very  shai'ply- 
defined  rim;  segments  eight  to  twelve 
times  longer  than  broad,  basal  injlation 
having  another  smaller  one  above  it,  sides 
otherwise  straight,  ^ara//^'/;  ends  crenate, 
owing  to  a  nimiber  of  emarginations 
from  the  edge  of  the  truncate  extremi- 
ties, from  three  to  five  of  the  crena- 
tm'es  being  usually  visible ;  e.  f.  punc- 
tate, or  rough  with  minute  granules. 
Sporangium  suborbicular  or  elliptic,  or 
slightly  angular,  smooth,  placed  between 
the  deciduous  empty  fronds.  Ciliated 
zoospores  formed  by  segmentation  of  the 
cell-contents,  and  their  emission  effected 
through  the  opened  apex  of  each  of  one, 
two,  or  three  specially-formed  lateral 
tubes  arising  from  beneath  the  base  of 
one  of  the  segments  (vide  supra,  p.  716 ; 
m.46,47).  L.  1-71"  to  1-59";  B.  1-1111" 
to  1-961".  (n.  8  .t  11.)  =  Pleurotmiium 
MrenberghUmeB&Yv).  G.B.,  I.,  R,  G., 
U.S.A. 


entire;  e.  f  punctate.  L.  1-65" ;  B.  1-813". 
(ii.  9.)  =  Pleurotcenium  davatum  (De 
Baiy).     G.B.,  I.,  F.,  G.,  U.S.A. 

D.  nodulosum  (Breb.).  —  Frond  vei-y 
stout,  the  thickened  suture  forming  a 
projecting  rim ;  segments  fom'  to  six 
times  as  long  as  broad,  scarcely  atte- 
nuated, regularly  injlated  at  intervals  so 
as  to  produce  an  undulated  margin,  the 
basal  inflation  the  most  prominent,  the 
others  as  they  approach  the  ends  less  so, 
where  they  are  indistinct  or  wanting; 
ends  entire ;  e.  f.  coarselv  punctate.  L. 
1-50";  B.  1-428".  =I>.  crenulatum  (Ehr.), 
Pleurotcenium  nodulosum  (De  Bary). 
G.B.,  I.,  F.,  G.,  U.S.A. 

D.  truncatum  (Breb.).  —  Frond  stout, 
the  thickened  sutm-e  forming  a  rim ;  seg- 
ments three  or  fom'  times  longer  than 
broad,  tapering,  basal  inflation  solitary, 
sides  othericise  gradually  curved ;  ends  en- 
tire; e.  f  -punctsite.^ Pleurotcenitwi  trun- 
catum (Nag.,  De  B.).  L.  1-81"  to  1-72" ; 
B.  1-527"  to  ]-429".     G.B.,  I.,  F.,  G. 

D.  co?istrictu?n  (Bailey). — Frond  stout, 
suture  not  prominent ;  segments  five  or 
six  times  longer  than  broad,  not  at- 
tenuated, with  four  distinct  eqiddistant 
sitiuations  producing  four  equal  gently 
curving  prominences  besides  the  basal 
inflation;  ends  entire.     U.S.A. 

D.  Baculuni  (Breb.). — Frond  slender, 
suture  not  prominent ;  segments  very 
many  times  longer  than  broad,  basal 
inflation  very  conspicuous,  solitary,  sides 
otherwise  straight,  \qyy  nearly  parallel, 
large  granules  of  the  "^endochrome  in  a 
single  series ;  ends  entire ;  e.  f  without 
puncta.  L.  1-111" ;  B.  1-1937".  (iii.  38.) 
=  Pleurotcenium  Baculum  (De  Barv). 
G.B.,  F.,  G.,  U.S.A. 

D.  minutum  (Balfs).  —  Frond  slender, 
suture  not  prominent ;  segments  four  to 
six  times  longer  than  broad,  somewhat 
tapering,  injlation  obsolete,  sides  straight^ 
ends  entire ;  e.  f  without  puncta.  L. 
1-212";  B.  1-1582".  =  Penium  Ralfsii 
(De  Bary).     G.B.,  I.,  F.,  G.,  U.S.A. 

D.  hirsutu7n  (Bailey).  —  Frond  rather 
slender,  sutiu'e  not  prominent,  segments 
four  to    six   times  as  long  as    broad. 


^46 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


not  tapering^  inflation  obsolete,  ends  en- 
tire, surface  all  over  minutely  spinous,  or 
Mrsute.     U.S.A. 

Kiitzing  (Sp.  Alg.)  describes  one  or 


two  other  species  of  Docidium ;  but  the 
characters  given  seem  hardly  distinctive, 
and  appear  sometimes  more  like  generic 
characters  re-stated. 


Genus  TETMEMORUS  (Ralfs).— Frond  elongate,  Btraight,  cyHndiical  or 
fusiform,  constricted  at  the  middle ;  segments  more  or  less  tapering,  not  in- 
flated at  the  base,  ends  with  an  acute  incision,  the  subdivisions  rounded, 
otherwise  quite  entire. 


Tetimemobus  Brehissonii  (Ralfs).  — 
Frond  about  five  or  six  times  longer 
than  broad ;  in  f.  v.  tcith  parallel  sides, 
the  constriction  a  very  shallow  groove ; 
in  s.  V.  fusiform,  the  constriction  very 
slightly  deeper ;  endochrome  with  a  lon- 
gitudinal series  of  light-coloured  large 
granules ;  e.  f.  punctate,  the  puncta  in 
longitudinal  rows.  L.  1-142" ;  B.  1-704". 
(ii!  12  &  13.)  =  Closterium  Brehissonii 
(Menegh.),  Penium  monile  (Kg.);  P-  ^^^'*'- 
ato-punctatum  (Kg.)  ?  G.B.,  I.,  F.,  G., 
Italy,  U.S.A.   /3,  turgidus,lsiVgeY,  stouter, 

constriction  deeper,    y, (De  Bary), 

smaller  than  either,  otherwise  externally 
similar,  endochrome  in  longitudinal 
fiUets. 


broadly  elliptic  ;  in  s.  v.  compressed, 
enclosed  in  a  central  cell  placed  between 
the  ultimately  deciduous  emptv  fronds. 
L.  1-374"  to  1-336";  B.  1-1244"  to 
1-1073".  =  Penium  (Tetmemorus)  Bre- 
bissonii  (Kg.).     G.B.,  I.,  F.,  G. 

T.  7ninutus  (De  Bary). — Frond  minute, 
shorter  than  T.  Iceris,  about  three  times 
longer  than  broad,  fusiform,  the  con- 
striction a  very  shallow  gi'oove  ;  e.  f. 
without  puncta.  L.  1-41"';  B.  1-118"'.   G. 

T.  granulatus  (Ralfs). — Frond  some- 
what longer  than  T.  Brehissonii,  about 
five  or  six  times  longer  than  broad ;  m 
both  f  V.  and  s.  v.  fusiform,  the  constric- 
tion a  very  shallow  groove,  ends  tcith  a 
hyaline  lip-like  projection  extending  be- 


T.  Icevis  (Ralfs). — Frond  smaller  than    yond   the   notch  ;    endochrome  vdth   a 


last,  scarcely  one-half  its  length,  about 
three  or  fom-  times  as  long  as  broad; 
in  f  V.  somewhat  tapering,  the  constric- 
tion a  shallow  depression  -,  in  s.  v.  fusi- 
form; end  sometimes  with  a  hyaline 
lip-like  projection  extending  beyond  the 
notch ;  e.  f!  punctate,  puncta  faint  but 
evident,  scattered.  Sporangium  smooth, 
in    f.  V.   at    first  quadrate,    afterwards 


longitudinal  series  of  large  granules: 
e.  f.  punctate,  the  puncta  scattered,  ex- 
cept near  the  constriction,  where  they 
are  disposed  in  two  transverse  rows. 
Sporangium  orbicular,  smooth,  margin 
finely  striated,  placed  between  the  de- 
ciduous empty  fronds.  L.  1-130";  B. 
1-Q4Q".= Penium  (T.)  grantdatus  (Kg.). 
G.B.,  I.,  F.,  G.,  Italy,  U.S.A. 


Genus  CLOSTERIUM  (Nitzsch). — Frond  elongate,  attenuate,  more  or  less 
Innately  curved  or  arcuate,  entire,  not  constricted  at  the  middle,  the  junction 
of  the  segments  marked  by  a  pale  transverse  band.  Endochi'ome  often 
arranged  in  longitudinal  fillets,  and  at  each  extremity  having  a  terminal  clear 
space,  in  which  are  active  granules  ;  e.  f.  smooth,  or  with  longitudinal  striie, 
never  granulate. 

The  subdi-v^isions  of  this  genus  cannot  always  be  rigidly  adhered  to,  as 
certain  species  might  sometimes  seem  to  agree  almost  as  well  with  another 
division  as  with  that  in  which  they  are  placed. 


*  Frond  scarcely  tapering,  the  curvature 
very  slight,  gradual  and  equal;  lower 
margin  nearly  straight  or  slightly  con- 
cave;  ends  truncate  or  broadly  rounded; 
e.f.  with  or  without  longitudinal  strice. 

Clostebitim:  didymotocum  (Corda). — 
Frond  stout,  six  to  ten  times  longer  than 
broad,  nearly  straight,  very  slightly  taper- 
ing to  the  extremities,  upper  margin 
slightly  convex,  lower  nearly  straight  or 
very  slightly  concave,  sometimes  slightly 


inclined  upwards  at  the  end ;  ends  trun- 
cate, reddish ;  large  granules  in  a  single 
series ;  e.  f.  reddish,  especially  near  the 
ends,  strice  faint ',  central  sutm-e  evident, 
sometimes  accompanied  by  two  others 
dividing  the  frond  into  four  portions. 
L.  1-65";  B.  1-813".  (iii.  39.)  G.B.,I., 
F.,  G.  a,  three  transverse  sutures;  /3, 
one.  =  C.  subrectum  (Kg.),  C.  Baileyamim 
(Breb.). 

C.  obtusum  (Breb.). — Frond  minute, 
fom'  to   ten    times    as   long  as  broad, 


or  THE  DESMIDIEiE. 


747 


nearly  straight,  cylindrical,  not  tapering, 
up2)er  and  lower  margin  equally  and  hut 
very  slightly  curved,  ends  ohtusely  rounded; 
large  granules,  in  a  single  series ;  e.  f. 
smooth.     F. 

C.  Amhlyonema  (Ehr.).  — Frond  stout, 
very  long,  twenty  to  twenty-five  times 
as  long  as  broad,  slightly  curved,  scarcely 
tapei'ing,\i^T^ev  and  lower  margins  equally 
and  but  gently  cur^^ed  ;  ends  broadly 
rounded;  e.  f.  smooth.     U.S.A. 

2  *  Frond  tapering,  having  the  curvature 
slight :  loiver  margin  straight  or  very 
slightly  concave,  and  slightly  inclined 
upwards  towards  the  rounded  or  sub- 
acute ends;  e.  f.  icith  or  ivithout  lon- 
gitudinal strice. 

C.  Lunida  (Ehr.). — Frond  large,  stout, 
five  or  six  times  as  long  as  broad,  semi- 
lunate,  iip^^er  margin  very  convex,  lower 
nearly  straight,  someivhat  inclined  upwards 
towards  the  obtuse  broadly  rounded  ends; 
endochrome  with  the  large  granules 
numerous,  scattered,  fillets  several,  di- 
stinct ;  e.  f.  colomiess,  without  mark- 
ings, central  sutm^e  not  evident.  L. 
1-62";  B.  1-330".  =  Vibrio  Lunida 
(Miiller),  Bacillaria  Lunula  (Schrank), 
Lunulina  vulgaris  (Bory).  G.B.,  F.,  I., 
G.,  Italy,  U.'SA.,  Mexico. 

C.  acerosum  (Ehr.).  —  Frond  slender, 
six  to  fifteen  times  as  long  as  broad, 
linear-lanceolate,  gradually  tapering, 
upper  margin  slightly  convex,  the  lower 
nearly  straight,  slightly  inclined  upwards 
at  the  conical  ends ;  large  gi'anules  in  a 
single  central  longitudinal  series ;  fillets 
several,  distinct ;  e.  f.  colomiess,  very 
faintlv  stiiated,  central  suture  evident. 
L.  1-70"  to  1-58" ;  B.  1-1103"  to  1-510". 
Sporangimn  orbicular,  smooth,  placed 
between  the  dehiscing  deciduous  empty 
fronds.  =  Vibrio  acerosus  (Schi"ank). 
G.B.,  I.,  F.,  G.,  U.S.A.,  Mexico. 

C.  lanceolatum  (Kg.).  —  Frond  stouter 
than  C.  acerosum,  six  to  ten  times  longer 
than  broad,  semilanceolate,  gradually  ta- 
pering ;  upper  margin  convex,  lower 
nearly  straight,  inclined  upwards  to- 
wards the  tajiej-ing  subacute  ends ;  large 
granules  in  a  single  central  series ;  fillets 
several,  distinct ;  e.  f.  colourless,  usually 
without  markings,  sometimes  faintly 
striated,  central  suture  evident.  L. 
1-64";  B.  1-453".  =  CymbeUa  Hopkirkvi 
(Moore).     G.B.,  I.,  R,  G.,  U.S.A. 

C.  turgidum  (Ehr.).  —  Frond  stout, 
eight  to  twelve  times  as  long  as  broad, 
semilanceolate,  slightly  tapering.,  more 
curved  than   either   of  the  preceding, 


upper  margin  convex,  tvith  a  depression 
near  each  extremity,  lower  margin  con- 
cave, inclined  upwards  towards  the 
rounded  ends ;  large  granules,  in  a  single 
longitudinal  series ;  fillets  several ;  e.  f. 
reddish,  longitudinal  strice  close,  distinct, 
central  sutm*e  evident.  L.  1-39" ;  B. 
1-370".  (m.  40.)  =  a  decussatum  (Kg.)  ? 
G.B.,  L,  F.,  G.,  U.S.A. 

C.  prcelongum  (Breb.).  —  Frond  very 
slender,  extremely  long,  thirty-five  to 
forty  times  as  long  as  broad,  slightly 
curved,  vei-y  gradually  tapering;  upper 
margin  slightly  convex,  with  a  depres- 
sion near  each  extremity ;  lower  concave, 
inclined  upwards  towards  the  roimded 
ends ;  large  gTanules  in  a  single  series ; 
e.  f.  colourless,  without  markings.     F. 

C.  quadrangulare  (Corda).  —  Frond 
very  slender,  twenty-five  to  thirty  times 
as  long  as  broad,  slightly  curved,  gra- 
dually tapering,  quadrangular,  except  at 
the  extremities,  one  of  the  angles  forming 
a  p>rominent  longitudinal  median  line ; 
upper  margin  equally  convex,  lower  con- 
cave, very  slightly  inclined  upwards  at  the 
blimt  ends ;  e.  f  colourless,  smooth.     G. 

3  *  Frond  tapering,  the  lower  margin 
concave,  often  tvith  a  central  injiation, 
and  inclined  dowmvards  toicards  the 
rounded  or  subacute  ends ;  e.  f.  ivithout 
markings. 

t  Frond  slender,  curvature  very  slight. 

C.  strigosum  (Breb.). — Frond  slender, 
twelve  or  fifteen  times  as  long  as  broad, 
nearly  straight,  but  someivhat  curved  down- 
ivards  towards  the  attenuated  extremities : 
upper  margin  slightly  convex,  lower 
concave  tvith  a  gentle  central  iti/lation ; 
ends  acute ;  large  granules  in  a  single 
series  ;  e.  f  colomiess,  without  striae. 
Sporangium  orbicular,  smooth,  placed 
between  the  shortly  deciduous  empty 
fronds,  which  conjugate  soon  after  divi- 
sion, so  that  two  of  the  empty  segments 
are  considerably  shorter  than  the  other 
two.     F.  _ 

C.  macilenttun  (Breb.). — Frond  very 
slender,  sublinear,  twenty-five  or  thirty 
times  as  long  as  broad,  slightly  and 
very  gradually  cm'ved,  somewhat  taper- 
ing ;  upper  margin  slightly  convex,  lower 
slightly  concave ;  ends  someivhat  blunt ; 
large  gTanules,  in  a  single  series;  e.  f. 
colom-less,  without  striae.  Sporangium 
orbicular,  placed  between  the  for  some 
time  persistent  empty  fr-onds,  which 
conjugate,  as  in  last,  soon  after  divi- 
sion.    F. 


'48 


SYSTEMATIC  HISTOEY  OF  THE  INFrSOEIA. 


C.  gracUe  (Breb.).  —  Frond  very 
slender,  about  twenty-five  to  thirty 
times  as  long  as  broad,  linear,  nearly 
straight,  except  at  the  exti-emities,  which 
are  curved  downwards ;  sides  parallel, 
ends  obtuse ;  endochrojne  arranged  in  a 
zigzag  or  suhspiral  manner ;  e.  f.  without 
strice.  I.,  F.  This  species  resembles  C 
jimciduni,  a,  in  form,  but  diifers  in  the 
arrangement  of  the  endochrome  and  in 
the  absence  of  strise. 

2 1  Frond  crescent-shaped,  cui'vature 
considerable. 

C.  Bhrenhergii  (Menegh.).  —  Frond 
large,  stout,  about  five  or  six  times  as  long 
as  broad.  Innately  curved,  extremities 
tapering;  upper  margin  ver}^  convex, 
lower  concave  tcith  a  conspicuous  central 
injiation ;  ends  broadly  rounded  ;  large 
granules,  numerous,  scattered;  fillets  se- 
veral ;  e.  f.  colourless,  mthout  strise, 
central  sutm*e  not  evident.  Sporangia 
orbicular,  smooth,  placed  between  the 
but  slightly  connected  empty  conjugated 
fronds,  the  endochrome  during  the  pro- 
cess of  conjugation  emerging  from  the 
opened  apex  of  a  short  conical  extension 
from  each  under  side  of  each  younger 
segment  (or  shorter  cone)  of  each  pair  of 
recently  divided  fronds,  the  conjugating 
fronds  being  produced  immediately  pre- 
viously by  the  self-division  of  a  pair  of 
old  fronds — two  sporangia  being  thus  the 
ultimate  produce  of  the  two  original 
fronds.  L.  1-68" ;  B.  1-400".  (xvi.  10, 
11,  12,  13,  14.)  =  LunuUna  monilifera 
(Borv),  C.  Lunula  (Ehr.,  Hass.).  G.B., 
I.,  R,  a,  U.S.A. 

C.  moniliferum  (Ehr.). — Frond  smaller 
than  the  last,  stout,  five  or  six  times 
as  long  as  broad.  Innately  curved,  extre- 
mities tapering,  upper  margin  convex, 
lower  concave  with  a  central  injiation, 
ends  rounded ;  large  granules,  conspicuous, 
in  a  single  longitudinal  series ;  e.  f.  colour- 
less, without  strise,  suture  not  evident. 
L.  1-75"  to  1-60" ;  B.  1-510"  to  1-466". 
G.B.,  I.,  F.,  G.,  Italy,  U.S.A. 

C.  obtusangulum  (Corda).  —  Frond 
stout,  crescent-shaped,  four  or  five  times 
as  long  as  broad,  rapidly  attenuated, 
"  quadrangular  "  (six  angles  ?)  ;  upper 
margin  very  convex,  lower  concave  with- 
out a  central  injiation ;  ends  narrowly 
rounded ;  e.  f.  colourless,  without  mark- 
ings. 

C.  Jinneri  (Ralfs). — Frond  small,  di- 
stance between  the  extremities  six  or 
seven  times  the  breadth,  crescent-shaped, 
much  ciu'ved,  gradually  tapering  (some- 


times with  an  obscui'e  central  constric- 
tion) ',  upper  margin  very  convex,  lower 
very  concave  without  a  central  inflation ; 
ends  obtuse,  rounded ;  large  granules,  in 
a  single  series ;  e.  f.  colourless,  wdthout 
strife.  L.  1-281":  B.  1-1730".  G.B.,  I., 
F.,  U.S.A. 

C.  Leibleinii  (Kg-)- — Frond  somewhat 
stout,  distance  between  the  extremities 
six  or  eight  times  the  breadth,  crescent- 
shaped,  much  curved,  rapidly  attenuated:, 
upper  margin  very  convex,  lower  very 
concave,  often  with  a  slight  central  injia- 
tion ;  ends  subacute ;  large  gi-anules,  in  a 
single  series ;  fillets  few  or  indistinct ; 
e.  f.  somewhat  straw-coloured,  without 
strife  ;  suture  evident.  Sporangium  orbi- 
cular. L.  1-291"  to  1-165";  B.  1-1632" 
to  1-582".  (II.  1  &  5.)  G.B.,  I.,  F.,  G., 
Italy,  U.S.A.  /3  more  slender,  scarcely 
inflated  on  the  lower  margin. 

C.  Diance  (Ehr.).  —  Frond  slender, 
crescent-shaped,six  or  eight  times  as  long 
as  broad,  much  curved,  rapidly  attenu- 
ated ;  upper  margin  very  convex,  lower 
very  concave  without  a  central  injiation ; 
ends  subacute  loith  a  very  slight  emargi- 
tiation  at  the  upper  outer  extremity  ;  large 
granules,  in  a  single  series ;  e.  f.  some- 
what straw-coloured  or  faintly  reddish, 
without  strise,  suture  evident.  L.  1-143"; 
B.  1-1275".  =  e.  rujiceps  (Ehr.),  C.  arcu- 
atum  (Breb.)  ?,  C.  Venus  (Kg.)  ?,  C.  acu- 
minatum  (Kg.)  ?.  G.B.,  I.,  F.,  G.,  Italy, 
U.S.A. 

C.  incurvum  (Breb.). — Frond  minute, 
somewhat  stout,  crescent-shaped,  very 
much  curved,  rapidly  attenuated,  ends 
very  acute ;  e.  f,  without  strise.     F. 

4  *  Fronds  gradually  tapering,  curvature 
often  gradual,  lower  margin  concave, 
inclined  doivmvards  at  the  rotundato- 
truncate  or  sometimes  subacute  ends; 
e.  f.  striated. 

C.  incequale  (Ehr.).  —  Frond  minute, 
semilunate,  attenuated;  upper  margin 
very  convex,  lower  concave ;  extremities 
unequal,  conic,  very  acute ;  large  granules, 
scattered ;  e.  f.  prominently  striated.    G. 

C  costatum  (Corda). — Frond  stout, 
about  five  or  six  times  as  long  as  broad, 
Innately  ciu'ved,  attenuated ;  upper  mar- 
gin convex,  equally  arched,  lower  con- 
cave; Olds  obtuse,  rounded;  large  gi'anules, 
in  a  single  series ;  e.  f.  reddish,  strice  feio 
(about  six),  conspicuous ;  suture  evident. 
Sporangium  orbicular,  smooth,  placed 
between  the  deciduous  emptv  fronds. 
L.  1-75";  B.  1-384".  =  C.  turgidulum 
(Kg.).     G.B.,  I.,  F.,  G. 


OF  TKE  DESMIDIE.^. 


749 


C.  striolatwn  (Ehr.). — Frond  from  six 
to  ten  times  as  long  as  broad,  Innately 
cm-ved,  attennated;  upper  margin  con- 
vex, sliyhtly  dipressed  at  the  centre,  lower 
concave;  ends  vety  obtuse,  rounded; 
large  gTanules,  in  a  single  series ;  e.  f. 
reddish,  especially  near  the  ends,  strice 
very  numerous,  crowded,  transverse  su- 
tures nsualli/  three.  Sporangium  orbi- 
cular, smooth,  placed  between  the  de- 
hiscing deciduous  emptv  fronds.  L.  1-80" 
to  1-68" ;  B.  1-625"  to  1-535".  (ii.  2  &  6.) 
=  a  ref/ulare  (Breb.)  ?.  G.B.,  I.,  F.,  G., 
Italy,  U.S.A. 

C.  intermedium  (Ralfs). — Frond  slen- 
der, twelve  to  fifteen  times  as  long  as 
broad,  slightly  curved,  very  gently  taper- 
ing', upper  margin  convex,  gradually 
arched,  lower  slightly  concave  ;  ends  ob- 
tuse, rounded ;  large  gi-anules,  in  a  single 
series;  e.  f.  pale  straw -colom-ed,  strife 
distinct,  numerous,  hut  not  crowded;  trans- 
verse sutures  usuallv  more  than  three. 
L.  l-77"-l-54" ;  B.  1-1073".    G.B.,  I.,  F. 

C.  angustatum  (Kg.). — Frond  slender, 
ten  to  twenty  times  as  long  as  broad, 
sublinear,  slightly  curv-ed,  scarcely  atte- 
nuated; upper  margin  convex,  gradually 
arched,  lower  concave ;  ends  truncate, 
slightly  rounded ;  large  granules,  in  a 
single  series  ;  e.  f,  pale  reddish,  especially 
near  the  ends,  strice  few  (about  four),  very 
distinct,  transverse  sutures  usucdly  three. 
L.  1-60" ;  B.  1-1142".     G.B.,  I.,  F.,  G. 

C.Ju?widum  (Ralfs). — Frond  very  slen- 
der, from  about  fifteen  to  even  thirty- 
five  times  as  long  as  broad,  linear, 
straight  except  towards  the  extremities, 
which  are  somewhat  curved  downwards, 
ends  obtuse ;  e.  f.  nearly  colourless,  strice 
not  72umerous,  faint,  transverse  sutures 
usually  three.  Sporangium  orbicular, 
smooth,  placed  between  the  dehiscing 
deciduous  empty  fronds.  G.B.,  I.,  F. 
/3,  frond  stouter,  less  elongated. 

C.  uncinatum  (Kg.). — Frond  slender, 
tapering  to  a  stibacute  point,  suddenly 
curved  dotcnwccrds ;  e.  f.,  the  body  with 
strice  fine  and  close,  absent  at  the  extre- 
mities. 

C.  lineatum  (Ehr.). — Frond  slender, 
elongate,  from  about  eighteen  or  twenty 
to  twenty-five  times  as  long  as  broad, 
gently cmwed,  very  gradually  attenuated; 
upper  margin  unequally  convex,  being 
most  curved  near  the  ends,  lower  concave 
or  somewhat  protuberant  at  the  centre  ; 
sides  somewhat  parallel  for  a  portion  of 
their  length  ;  the  extremities  gradmdly  ta- 
pering, slender,  curved  doivnwards,  etids 
obtuse  ;  large  gi-anules,  in  a  single  series  ; 
e.  f.  reddish,  strics  numerous,  clisti?ict,  one 


or  more  transverse  lines  at  the  coitrcd  su- 
I  ture.  Sporangia  double,  rounded,  smooth, 
in  close  approximation,  their  opposed  sur- 
faces fiattened,  placed  between  the  de- 
hiscing, shortly-deciduous  empty  fronds, 
and  each  formed  by  the  mutual  conjuga- 
tion of  the  contents  of  the  adjacent  op- 
posite segments,  L.  1-48";  B.  1-909". 
(ni.  41,  42.)  G.B.,  I.,  F.,  G.,  Mexico. 
/3,  stria3  spiral ;  y,  stricie  very  faint,  except 
at  the  centre  of  the  fi^ond  (Breb.). 

C.  decorum  (Breb.).  —  Frond  about 
twelve  to  twenty  times  as  long  as  broad, 
tapering  from  the  centre,  graducdly  curved ', 
upper  margin  equally  convex,  lower 
margin  concave;  extremities  attenuated, 
slender,  obtuse ;  large  granules,  in  a  single 
series ;  e.  f.  colourless,  striae  numerous.  F. 

5  *  Frond  gradually  curved,  tapering,  sud- 

denly contracted  at  the  end  into  a  coni- 
ccd  point. 

C.  attenuatum  (Ehr.). — Frond  eight  to 
twelve  times  as  long  as  broad,  gently 
cm'\ed, gradually  attenuated;  upper  mar- 
gin slightly  convex,  lower  concave  ;  ex- 
tremities suddenly  contracted  into  an  obtuse 
coniccd point;  large  granides,  in  a  single 
series ;  e.  f.  reddish,  with  numerous  close 
striae,  central  sutm-e  evident.  L.  1-57" : 
B.  1-669".    (ill.  4:3.)     G.B.,  I.,  F.,  G. 

6  *  Frond  ventricose  or  narrow-lanceolate, 

rapidly  tapering  into  a  distinct  beak. 
(S/jorangia  c)i/cifor?n.) 

C.  Ralfsii  (Breb.). — Frond  stout,  six 
to  nine  times  as  long  as  broad ;  the  upper 
margin  slightly  convex,  the  lower  concave, 
hut  ventricose  at  the  middle;  each  extremity 
tapering  into  a  narrow,  slender,  reddish 
beak,  shorter  than  the  body,  slightly  curved 
downwards,  ends  obtuse ;  large  gi'anules, 
conspicuous,  ia  a  single  series ;  e.  f.  red- 
dish, especially  near  the  ends,  striae  nu- 
merous, close,  and  distinct,  centred  suture 
accompanied  by  several  transverse  lines. 
L.  1-79" ;  B.  1-526".     G.B.,  F. 

C.  rostratum  (Ehr.).  —  Frond  from 
about  ten  to  fifteen  times  as  long  as 
broad,  lanceolate;  upper  andloicer  margins 
nearly  equcdly  convex ;  each  extremity 
tapering  into  a  narrow,  setaceous,  nearly 
colourless  beak,  nearly  equal  in  length  to 
the  body,  cm'^-ed  do\\Tiwards,  ends  obtuse ; 
large  granides,  in  a  single  series ;  e.  f. 
colourless  or  somewhat  straw-coloured, 
striae  numerous,  close;  suture  solitary. 
Sporangium  somewhat  crucifonn,  its 
sides  concave,  its  extensions  trimcate, 
attached  to  the  emptv  conjugated  fronds. 
(III.  44.)     L.  1-69" ;  "'B.  1-680'.     C.  cau- 


750 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


datum  (Corda),  Stauroceras  Acus  (Kg.). 
G.B.,I.,F.,G.,Italy. 

C.  elegans  (I3reb,). — Frond  veiy  slen- 
der (twenty-five  to  thirty  times  as  long 
as  broad),  narrow-lanceolate^  upper  and 
lower  margins  nearly  equally  convex, 
each  extremity  tapering  into  a  long,  slen- 
der, setaceous,  colourless  beak,  about  as 
long  as  the  body,  ultimately  cui'ved  do-svn- 
wards,  ends  acute  5  large  granules,  in  a 
single  series  j  e.  f.  without  strice.     F. 

C.  setacemn  (Ehr.). — Frond  very  slen- 
der, from  about  twenty  to  twenty-five 
times  as  long  as  broad,  narroiv-lanceo- 
late;  upper  and  lower  margins  nearly 
equally  and  hut  slightly  convex  ;  each  ex- 
tremity tapering  into  a  very  long,  slen- 
der, setaceous,  colourless  beak,  longer 
than  the  body,  idtimately  curved  down- 
wards, ends  obtuse ;  e.  f.  colourless,  strice 
close,  faint,  central  suture  solitary.  Spo- 
rangium cruciform,  similar  to  the  last.  L. 
1-116";  B.  1-2^Q\" .  =  Stauroceras  subu- 
latuni  (Kg-)?  ^'  intermedium  (Kg.),  C. 
KutzingU  (Breb.).  G.B.,  1.,  F.,  G.,  Italy, 
U.S.A. 

C.  irronum  (Breb.). — Frond  very  slen- 
der (thirty  to  thirty-five  times  as  long 
as  broad),  nearly  straight;  upper  and 
lower  margin  scarcely  inflated,  nearly 
equally  though  very  slightly  convex ;  very 
gradually  attenuated  at  each  extremity 
into  a  long,  slender,  setaceous,  colomless 
beak,  ultimately  somewhat  curved  down- 
wards, ends  slightly  enlarged  and  rounded', 
e.  f.  colomless,  without  strice.     F. 

7  *    Frond    minute,   tapering,  curvature 
very  slight,  neither  injlated  nor  rostrate. 
{Sporangia  cruciform.) 
C.  Cormi  (Ehr.). — Frond  minute,  fr-om 


five  to  eight  times  as  long  as  broad, 
slender,  slightly  cun'ed,  attenuated,  etuis 
blunt;  endochrome  not  reaching  to  the 
extremities ;  large  granules,  indistinct,  in 
a  single  series  ;  e.  f.  colouiless,  without 
striae.  Sporangium  in  f.  v.  somewhat 
cruciform  or  quadrate,  with  the  angles 
produced  and  roimded,  in  s.  v.  elliptic, 
attached  to  the  conjugating  fronds.  L. 
1-140"  ;  B.  1-3709".  =  C.  tenue  (Kg.). 
G.B.,  F.,  I ,  G.,  Italy.  ^,  frond  more  tm*- 
gid.    L.  1-226" ;  B.  1-2142".   G.B.,  L,  F. 

0.  acutuni  (Breb.), — Frond  somewhat 
larger  than  the  last,  about  from  six  to 
twenty  times  as  long  as  broad,  slender, 
narrow-lanceolate,  slightly  curved,  gi"a- 
dually  attenuated,  ends  acute ;  e.  f.  co- 
lourless, Avithout  strise.  Sporangium 
similar  to  last.  L.  1-177" ;  B.  1-2550". 
G.B.,  L,  F.,  G.  a  six  to  twelve  times 
as  long  as  broad,  ends  subacute.  j3  ten 
to  twenty  times  as  long  as  broad,  ends 
very  acute.  =  Stauroceras  subulatum 
(Kg.)?,  C.  subulatmn  (Breb.)  ?,  C.  tener- 
rim,um,  (Kg.)  ? 

C.  Gripthii  (Berk.). — Frond  minute, 
scarcely  curved,  acicular,  verv  acute, 
smooth.  =  a  subtile  (Breb.)  ?   G.B.,  I.,  F. 

8  *  Frond  crescent-shaped,  stout,  extre- 
mities furnished  with  a  single  acute 
spine. 

C.  euspidatum  (Bailey). — Frond  stout, 
crescent-shaped,  scarcely  tapering,  much 
curved,  ends  rounded,  furnished  tvith  a 
single  subulate  acute  sjnne ;  e.  f.  without 
striae.  U.S.A.  We  are  disposed  to  think 
this  plant  may  not  be  a  true  Desmidiean, 
but  belong  to  the  genus  Ophiocytium 
(Nag.),  though  placed  in  Closterium  by 
Bailev. 


Genus  PENIUM  (Breb.). — Frond  elongate,  straight,  cylindrical,  elliptic, 
or  lanceolate,  either  not  at  all  constricted  or  hut  very  slightly  narrowed  at  the 
middle,  entire.  Endochrome  with  or  without  a  terminal  clear  space,  con- 
taining active  granules. 


*  Empty  frond  granidate,  generally 
reddish. 

Penium  margaritaceum  (Breb.).  — 
Frond  six  to  ten  times  as  long  as  broad, 
fusiform  or  cylindrical,  with  rotundato- 
truncate  ends,\'ough  with  pearly  gi-anules 
arranged  in  longitudinal  lines.  Endo- 
chrome at  each  end,  sometimes  with  a 
more  or  less  distinct  terminal  cavity  with 
active  granules.  Sporangium  orbicular, 
smooth.  =  Closterium  margaritaceum 
(Ehr.).  G.B.,L,F.,G.  a,  frond  fusiform, 
gradually   constricted    at    the    middle. 


granules  distinct.  L.  1-156" ;  B.  1-961". 
(11.  14.)  /3,  frond  linear,  scarcely  con- 
tracted at  the  middle,  gTanides  distinct, 
y,  frond  linear,  not  contracted  at  the 
middle,  gTanules  appearing  like  pimcta. 
L.  1-169"  ;  B.  1-1515".     (11.  15.) 

P.  Cylindrus  (Breb.).— Frond  minute, 
red,  three  or  four-  times  as  long  as 
broad,  cylindrical,  not  contracted  at  the 
middle,  ends  rotundato-truncate,  rough 
with  minute,  closely  scattered,  pearly 
granules ;  e.  f.  red.  L.  1-492" ;  B.  1760". 
=  Closterium  Cylindrus(E\\v.),Dysphinc- 
tium  Cylindrus  (Nag.).     G.B.,  I.,  F.,  G. 


OF  THE  DESMIDIE^. 


751 


P.  annulatum  (Nag.  sp.). — Frond  mi- 
nute, scarcely  tioice  as  long  as  broad, 
cylindrical  or  suhelliptic,  sides  and  ends 
broadly  rounded,  rough  ^dth  minute  gra- 
nules arranged  in  transverse  lines,  whicli 
give  a  minutely  denticulate  appearance 
to  the  margin,  except  at  a  very  nan'ow 
central  annular  space,  where  they  are 
absent,  thus  imparting  a  somewhat  con- 
stricted appearance ;  e.  v.  circular,  margin 
minutely  granulate.  =  Dysphinctium  an- 
nulcdum  (Nag.).     I.,  G. 

2*  Empty  frond  smooth,  colourless. 

P.  Digitus  (Breb.). — Frond  large,  stout, 
smooth,  three  or  four  times  as  long  as 
broad,  elliptic  -  oblong,  sides  and  ends 
broadly  rounded  ;  endochrome  in  obscure 
and  undulated  fillets,  interrupted  only  by 
the  pale  central  transverse  band,  and  hay- 
ing no  clear  space  at  the  extremities. 
L.  1-81";  B.  1-299".  =  Closterium  Digitus 
(Ehr.),  Peniuni  oblonqum  (De  Bary)? 
G.B.,  I.,  R,  G.,  U.S.A. 

P.  lameUosum  (Breb.). — Frond  large, 
stout,  smooth,  about  four  times  as  long 
as  broad,  gradually  contracted  at  the 
middle,  and  tapering  to  the  extremities, 
ends  somewhat  truncate ;  endochrome  in 
obscure  and  undulated  filets,  in  transverse 
view  radiate,  its  rays  divided,  and  hav- 
ing no  clear  space  at  the  extremities. 
F.,  G. 

P.  Ncegelii  (Breb.  in  litt.).  —  Frond 
large,  stout,  smooth,  about  four  times 
longer  than  broad,  oblong,  oiot  contracted 
at  the  middle,  gradually  tapering  to  each 
exti'emity,  sides  nearly  straight,  ends 
broadly  truncate;  endochrome  arranged 
in  intej'rupted  divided  planes  radiating 
frojn  the  central  axis,  in  f.  v.  being  in' 
dented  somewhat  in  a  pinnatijid  manner, 
the  rays  touchmg  the  cell  wall,  some- 


times divided,  and  somewhat  dilated 
thereat,  in  transverse  view  radiate.  = 
Closterium  (Netriimi)  Digitus  (Niig.). 
I.,  G. 

P.  interruptum  (Breb.). — Frond  large, 
stout,  smooth,  three  or  four  times  as  long 
as  broad,  cylindrical,  sides  parallel,  ex- 
tremities conical,  and  rounded  at  the  ends ; 
endochrome  disposed  in  straight,  strongly 
marTxcd  filets,  interrupted  by  three  trans- 
verse pale  bands,  having  a  roimded,  well- 
defined  clear  space  near  the  ends,  in 
which  are  active  gi-anules.  L.  1-116" ; 
B.  1-571".  (III.  45.)  G.B.,  I.,  F.,  G., 
U.S.A. 

P.  closterioides  (Ealfs). — Frond  rather 
large,  about  six  times  as  long  as  broad, 
smooth,  fusiform  or  lanceolate,  ends 
broadly  rounded ;  endochrome  in  distinct 
longitudinal  fillets,  interrupted  only  by 
the  central  transverse  pale  band,  with  a 
single  longitudinal  series  of  large  granules, 
and  a  rounded  clear  space  close  to  the 
ends,  in  which  are  active  granules,  L. 
1-92";  B.  1-590".     G.B.,  I.,  F.,  U.S.A. 

P.  Navicula  (Breb.). — Frond  minute, 
about  three  or  fom'  times  as  long  as 
broad,  smooth,  fusiform,  ends  bluntly 
pointed;  endochrome  sometimes  in  fil- 
lets, sometimes  scattered,  internipted 
only  by  the  transverse  central  pale  band, 
ivith  one  or  two  large  gramdes  in  each 
half,  and  a  rounded  clear  space  at  the 
ends,  in  which  are  active  gi-anules.  L. 
1-420";  B.  l-750".=V.£erginii(ArcheT). 
I.,F. 

P.  trunccdimi  (Breb.). — Frond  minute, 
two  to  four  times  as  long  as  broad, 
cylindrical,  smooth,  ends  trunccde.  Spo- 
rangimn  orbicular,  smooth,  placed  be- 
tween the  dehiscing,  deciduous  empty 
fronds.  L.  1-969"  to  1-555"  J  B.  1-2212" 
'to  1-2100".     G.B.,I.,F. 


Genius  SPIEOTJENIA  (Breb.). — Frond  elongate,  straight,  cylindrical,  or 
fusiform,  entire,  not  constricted  at  the  middle,  ends  rounded  or  acute ;  endo- 
chrome spiral.  (Gelatinous  investment  very  apparent ;  ceU-division  oblique ; 
fructification  unkno^Ti,  therefore  the  position  of  this  genus  uncertain.) 


*  Endochrome  a  single  spiral  ba^id. 

SpEROT^isnA  condensata  (Breb,).  — 
Frond  cylindrical,  five  to  ten  times 
as  long  as  broad,  ends  rounded ;  en- 
dochrome a  single,  broad,  closely-ivound 
spiral  band,  its  revolutiojis  nimier'ous.  L. 
1-208"  ;  B.  1-1048".  (n.  4.)  G,B,,  I,, 
F,,  G,,U,S,A, 

S,  muscicola  (De  Bary), — Frond  cylin- 
drical, two  to  four  times  as  long  as 
broad,    ends    rounded  ;    endochrome   a 


single,  broad,  smoothly-defined,  icidely- 
ivound  spiral  band,  its  revolutions  very 
few  (one  or  two).  L,  1-142"'  to  1-71'" ; 
B,  1-2S7 "'.=Palmogl(ra  endospira  (Kg.), 
Cylindrocystis  endospira  et  Eridospira 
trimcorum  (Breb.,  Kg,),     F,,  G. 

S.  erythrocephala  (Itzigsohn,  Braun). 
Frond  fusiform,  five  or  six  times  as  long 
as  broad,'  ends  acute ;  endochrome  a 
single,  rather  narrow  spiral  band,  its 
revolutions  few.  =  S.  mimita  (Thuret, 
Breb.),     F.,  G. 


752 


SYSTEMATIC  HISTORY  OF  THE  rNTUSOEIA. 


2  *  Endochrome  i?i  several  spi?'al  bands. 

S.  ohscura  (Ralfs). — ^Frond  cylindrical 
or  fusifomi,  five  to  eight  times  longer 
than  broad,  extremities  attenuated,  ends 
blunt ;  endochrome  in  several  slender  spi- 

C.   Cells 

Genus  COSMOCLADIIJM  (Breb.). 
constricted  at  the  middle,  stipitate. 

CosMOCLADiuiM  pulchellmn  (Breb.). — 
Stipes  dendroid,  dichotomously  branched, 
hyaline,  with  a  slight  intermediate  thick- 
ening between  the  cells ;  cells  terminal 
and  axillary,  green,  segments  elliptico- 
reniform,  smooth  (iii.  63).     F. 

We  here  provisionally  place  this  re- 


7'al  hands,  their  revolutions  two  or  three. 


!  at  each  extremity,  in  which  there  is 
sometimes  a  free  granide.  L.  1-247"  to 
1-226";  B.  1-1020"  to  1-907".  G.B., 
I.,  F. 

sti/pitate. 

—  Cells  rounded,  compressed,  deeply 

markable  plant,  discovered  by  M.  do 
Brebisson,  not  knowing  as  yet  anything 
as  to  its  mode  of  growth  or  development. 
The  ceUs,  if  detached  from  the  stipes, 
woidd  scarcely  be  distinguishable  from 
those  of  Cosmarium  bioculatum. 


D.  Cells  aggregated  into  families,  forming  fasciculi  or  faggot-like  bundles. 

Genus  AKKISTBODESMrS  (Corda).— Cells  minute,  smooth,  elongated, 
attenuated,  aggregated  into  families  forming  fasciculi  or  faggot -like  bundles, 
each  family  resulting  from  the  self-division  of  a  single  cell,  wMch  commences 
by  the  formation  of  a  somewhat  oblique  septum  at  the  middle,  eventually 
rendered  more  and  more  oblique  from  the  young  cells  growing  alongside  one 
another  longitudinally  until  they  each  attain  the  length  of  the  original  parent- 
ceU,  the  process  being  again  and  again  repeated  by  each  till  the  aggregated 
family  consists  of  at  most  thirty-two  cells,  the  family  finally  again  breaking 
up  into  single  cells.  No  other  propagation  known ;  the  position  of  the  genus 
is  therefore  doubtful. 


Ankisteodesmus  falcatus  (Ralfs). — 
Cells  very  slender,  arcuate  (rarely  straight 
or  sigmoid),  graduallv  attenuated,  ends 
acute.  L.  1-550";  B.  1-7353".  (i.35,36.) 
=  Rhaphidium  fasciculatu?n  (Kg.,  Nag.). 
G.B.,  I.,  F.,  G.,  Italy. 

A.  convoliitus  (Corda).  —  Cells  much 
curved,  crescent-shaped,  somewhat  ra- 
pidly attenuated,  ends  subacute.  =  -R/i«- 
phidium  minutum  (Nag.).  I.,  F.,  G. 
We  have  met  with  a  plant  (gathered 
near  Dublin)  which  we  now  (though 
doubtfully)  refer  to  this  species,  in  which 
we  noticed  self-division  of  the  cells,  in 
an  at  first  oblique,  finally  longitudinal 
manner,  very  much  the  same  as  that 
described  by  Nageli  {Einzell.  Aly.)  for  the 
preceding  species,  and  introduced  into 
the  generic  character.      The  cells  in  our 


plant  are  not  quite  so  much  curved  as  in 
Nageli's  drawing  of  this  species,  and  are 
rather  more  acute  at  the  extremities : 
we  have  not  noticed  the  fascicidi  to  be 
composed  of  more  than  8  cells,  frequently 
of  2  or  4  ;  and  while  so  combined  the  cells 
all  look  in  the  same  direction,  the  con- 
cave sm-face  of  the  one  being  applied  to 

I  the  convex  sm'face  of  its  neighbour. 

;  A.  contortus  (Thuret). — Cells  slender, 
arcuate  or  sigmoid,  somewhat  gently  in- 

!  flated  at  the  centre,  ends  drawTi  out  long 
and  very  fine.     F. 

[Scenodesmus  duplex  (Ralfs)  is  placed 
in  this  genus  by  Kiitzing  and  Nageli 
under  the  name  of  Rhaphidium ;  that 
plant  may,  however,  be  the  cell  of  an 
Ankistrociesmus  undergoing  division.] 


SubfamHy  PEDIASTRE^  (page  24). 

We  shall  not  attempt  to  give  anything  but  a  very  provisional  diagnosis  of 
the  genera  here  included  under  the  above  title  (which  have  long  been  asso- 
ciated with  the  Desmidiacese,  and  chiefly  for  that  reason  finding  a  place  in 
the  present  work),  as,  so  far  as  we  can  judge,  it  is  not  yet  determined  whether 
they  should  remain  united  with  the  Palmellacece,  to  which  they  have  been 


OF  THE  PEDIASTEE^. 


'53 


referred  by  jS'ageli,  or,  with  some  few  other  Algte,  form  a  distinct  group  near 
Pahnellaceae,  and  perhaps  Volvocinese.  They  cannot,  we  think,  continue 
to  be  considered  as  belonging  to  the  Desmidiaceae.  For  the  pui-poses  of  the 
present  work,  however,  as  they  are  introduced,  we  shall  just  indicate  that 
the  genera  here  described  under  the  above  head  agree  in  the  following 
characters : — 

Cells  combined  into  a  definitely  formed  frond  or  family,  often  cither  ex- 
ternally notched  or  attenuated,  sometimes  spinous,  not  undergoing  complete 
self-fission  in  the  same  direction  into  two  perfect  cells,  but  propagating  by 
the  repeated  segmentation  of  the  contents  of  the  old  cells  into  a  definite 
number  of  portions  or  "  gonidia,"  which  are  either  still  or  for  a  time  motile, 
and  which  are  either  arranged  according  to  the  typical  plan  within  the  parent- 
cell,  and  by  its  bursting  set  free  as  a  new  frond  or  family,  or  become  so 
arranged  without  the  parent-cell,  but  still  involved  in  its  inner  membrane, 
the  whole  ha\'ing  emerged  by  a  transverse  fissure. 

We  are  disposed  to  think  that  here  Hydrodictyon  should  come ;  for  though 
in  this  plant  the  development  of  the  active  gonidia  is  simultaneous,  not 
successional,  as  in  Pediastrium,  Pringsljeim  alludes  to  the  gonidia  in  Ccelas- 
trwn  sphcencum  (which  indeed  are  still)  as  either  the  one  or  the  other. 
Cruciagema  quadrata  (MoiTcn)  =Staurogenia  quadmta  (Kg.),  seems  to  pro- 
pagate by  complete  self-fission,  and,  gonidia  not  being  described,  we  believe 
cannot  belong  here.     As  to  Sphaerodesmus  (i^iig.)  information  is  wanting. 


Genus  SCEXODESMUS  (Meyen).— Frond  or  family  composed  of  from  two 
to  eight  oblong  fusiform  or  elliptic  cells,  mnnected  into  a  single  07^  double 
continuous  row ;  propagating  by  means  of  the  repeated  segmentation,  in 
parallel  planes  in  one  or  two  dii-ections,  of  each  of  the  cell- contents  into  one 
or  more  brood  families  (not  motile),  set  free  by  the  bursting  of  the  parent- 
ceU  wall.    (I^ag.) 


ScENODESMUS  qundricauda  (Ralfs). — 
Cells  in  a  single  low ;  oblong,  rounded  at 
then*  ends ;  external  cells  (sometimes 
more  turgid  than  the  others)  furnished 
at  each  extremity  icith  an  elongate^  often 
curved,  acute  spine  or  bristle,  sometimes 
with  another  from  the  centre  of  the 
outer  margin.  L.  1-1121" ;  B.  1-2631". 
(i.  40,  41,  4S.)=Achnanthes  quadricauda 
(Tui-p.),  ArtJirodesmus  quadricaudatus 
(Ehr.),  Scenedesmus  caudatus  (Corda, 
Kg.),  S.  quadricaudatus  (Hass.).  G.B., 
I.,  F.,  G.,  U.S.A.  /3,  central  cells  fur- 
nished at  one  of  their  ends  with  an 
elongate,  acute,  curved  spine  or  bristle, 
each  half  of  the  frond  being  so  fm-nished 
at  opposite  sides,  sometimes  the  central 
cells  being  also  fm-uished  at  their  other 
ends  watli  a  verv  short,  minute  spine. 
=  .S'.  A%e/«(Breb.).  (i.  42.) 
.  S.  dispar  (Breb.). — Cells  two  or  four, 
alternating,  oblong,  bhmt  at  the  ends ; 
when  fom*  the  central  cells  at  one  end  at 
opposite  sides  of  the  frond  furnished  %x\th 
a  short  acute  mucro-like  dejected  spine, 
each  spine  directed  inwards ;  when  either 
two  or  four,  the  external  cells  with  a 
similar  spine  at  both  ends;  when  four, 


I  that  spine  at  the  same  side  of  the  frond 
I  with  that  belonging  to  the  central  cells 
I  also  directed  inwards,  the  other  directed 
j  outwards.     F. 

I      S.    antennatus   (Breb.).  —  Cells   in   a 
I  single  or  double  row ;  fusiform,  or  semi- 
lunate,  ends  cuspidate,  and  each  tefrmincded 
by  a  minute  orbicular  globule.     F. 

S.  dimorphus  (Kg.). — Cells  in  a  single 
row ;  narrow,  attenuated,  and  pointed  at 
the  ends;  the  central  in  apposition  the 
most  of  their  length,  the  outer  externally 
lunate.  L.  1-1020"  to  1-906";  B.  1-8160". 
=  Achnnnthes  dimorpha  (Turp,),  S.  pcc- 
tinatus  (Meven),  ArtJirodesmus  pectinatus 
(Ehr.).     G.B.,  I.,  F.,  G. 

S.  acutiis  (Meyen).  —  Cells  in  alter- 
nating rows;  the  central  fusiform,  in 
app)osition  only  at  their  middle,  the  outer 
sometimes  extemallv  lunate.  L.  1-1663" 
to  1-1060";  B.  l-62o0"  to  1-6181".  = 
Arthrodesmns  acutus  (Ehr.),  S.  acutus  et 
oUiquus  (Ralfs).  G.B.,  I.,  F.,  G.,  Italy. 
S.  obtusus  (Meyen). — Cells  in  one  or 
oblong,    end^ 


two    rows,    all    ovate 
rounded.     L.   1-2331" 
1-4096"   to   1-3623". 
G.B.,  L,  F.,  G.,  U.S.A 


or 

to   1-1961' 

(i.  37,   38, 

3c 


;    B. 

39.) 


754 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


S.  duplex  (Ealfs). — Cells  two,  slender, 
tapering,  skpnoid,  acute,  ^j/«re(^Z  side  hy 
side  for  about  half  their  lencjtli.  =  Rhaphi- 
dium  duplex  (Kg.),  nee  S.  7noniliformis 


(duplex)  (Kg.).  G.B.,  CI.  This  plant 
possibly  represents  a  cell  of  an  Ankis- 
trodesmus  during  division. 


Genus  PEDIASTHUM  (Meyen). — Frond  or  family  plane,  circular,  elliptic, 
or  irregular,  composed  of  several  cells  (a  multiple  of  four),  forming  by  their 
union  a  flattened  star-like  group,  generally  arranged  in  more  or  less  con- 
centric circular  series,  marginal  cells  externally  bipartite  or  entire ;  propa- 
gating by ''  macrogonidia,"  which  are  subgiobose,  formed  by  repeated  binary 
division  of  the  endochrome  of  each  of  the  parent-cells  of  the  old  frond,  2,  4, 
8,  16,  32,  or  G4  (even  128)  in  number,  and  making  theii'  exit  by  a  transverse 
fissure  from  the  parent-ceU,  involved  in  its  inner  membrane,  mthin  which 
for  a  time  they  actively  move,  presently  settling  down  and  arranging  them- 
selves into  a  new  frond ;  '"  microgonidia  "  produced  in  the  same  manner,  but 
shortly  rupturing  the  confining  membrane  and  swimming  freely  away,  their 
fate  unkno^\^l  (Braim). 


*  Lohes  of  the  outer  cells  two,  deeply 
emarginate  or  truncate. 

Pediasthum  Tetras  (Ralfs).  —  Frond 
very  minute  ;  cells  four,  their  interstices 
forming  a  ci'oss,  their  outer  margin  bi- 
"lobed,  angles  acute.  L.  1-2941" ;  B. 
1-2272".  (ii.  27.)  =  Micrasterias  Tetras 
(Ehr.),  P.  biradiatum  (Tetras)  (Kg.). 
G.B.,  I.,  F.,  G.,  U.S.A. 

P.  heptactis  (Menegh.). — ^Frond  minute; 
cells  eight  (seven  disposed  in  a  single  series 
round  a  central  one),  bilobed,  angular. 
L.  1-2900" ;  B.  1-2500".  =  Micrasterias 
heptactis  (Elir.),  Euastnmi  hexagonum 
(Corda),  P.  simplex  (Hass.),  P.  hira- 
diatum  (heptactis)  (Kg.).  G.B.,  I.,  F., 
G.,  U.S.A. 

P.  biradiatum  (Menegh.). — Inner  cells 
subcpiadrilateral,  with  a  linear  notch,  the 
outer  quadrilateral  or  somewhat  cuneate, 
approximate  for  their  entire  length,  ex- 
ternally deeply  bipartite,  their  incisions 
narrow,  the  subdivisions  truncate  or 
truncate  -  emarginate.  L.  1-1200"  to 
1-2650"  ;  B.  1-1754"  to  1-2040;'.  =  Mi- 
crasterias Rotida  (Ehr.),  P.  biradiatum 
(Rotula)  (Kg.).  This  with  the  two  pre- 
ceding may  possibly  make  but  one  true 
species,  P.  Elirenberqii  (Braun.).  (i.  52.) 
G.B.,  I.,  F.,  G.,  U.S.A. 

P.  Rotula  (Ehr.  emend.  Braun).  — 
Inner  cells  with  a  tcide  notch,  and  sepa- 
rated by  wide  lacunae,  the  outer  subqua- 
drilateral,  approximate  only  at  their  bases, 
tchich  are  nearly  square,  externally  deeply 
bipartite,  their  incisions  broad,  the  sub- 
divisions naiTow,  inciso-dentate.    F.,  G. 

P.  caudatum  (Braun).  —  Inner  cells 
pentagonal  or  hexagonal,  with  a  deep 
linear  notch,  the  outer  quadrangidar, 
externally  deeply  bipartite,  the  subdivi- 


sions truncate,  very  slightly  concave  at 
the  centre,  aiul  furnished  at  the  angles  ivith 
a  very  minute,  shorty  bristle-like  spine. 
=  P.  Rotula  (Nag.).     G. 

2  *  Lobes  of  the  outer  cells  two,  entire, 
attenuated. 

P.  Selencea  (Kg.).  —  Cells  crescent- 
shaped,  arranged  in  one  or  more  circles 
round  one  or  two  central  ones,  connecting 
mediinn  coloured.  =  P.  elegans  (Hass.), 
P.  lunare  (Hass.).     G.B.,  F.,  G. 

P.  gracile  (Braun).  —  Frond  minute, 
of  fom-  or  six  cells  (fom*  external,  Vvdth 
or  without  two  central  cells)  ;  marginal 
cells  deeply  bipartite ;  subdivisions  ovate, 
tapering  to  a  point.  L.  1-1020"  ;  B. 
Y-Vo^'i" .■=  Micrasterias  Coromda  (Ehr.), 
P.  Napoleonis  (Hass.,  Menegh.,  Kg.,  nee 
Ralfs),  P.  simptex  (Ralfs).     G.B.,  F.,  G. 

P.  pertusum  (Kg.).  —  Cells  aiTanged 
in  circles  round  one  or  two  central  ones ; 
inner  cells  quadrangidar,  sides  concave 
and  leaving  angular  vacant  intervals ;  the 
outer  cells  tcith  square  bases,  externally 
triangidarly  notched,  the  subdivisions  ta- 
pering to  an  acute  point.  L.  1-2266"  ; 
B.  1-3268".  =  Micrasterias  Boryana 
(Ehr.),  P.  tricyclium  (Hass.),  P.  emargi- 
natuni  (pertusum)  (Kg.).  G.B.,  I.,  F.,  G. 

P.  granidatum  (Kg.).  —  Cells  eight, 
rough  loith  minute  granules,  six  cells 
arranged  round  two  central,  the  inner 
subquadrate,  the  outer  ha\-ing  two  taper- 
ing lobes.  L.  1-2000";  B.  1-1850". 
G.B.,  I.,  F.,  G. 

P.  A^fl;;o/eo«is (Menegh.).— CeUs  eight, 
six  an-anged  roimd  two  centi-al,  the  inner 
variable,  the  outer  having  two  cuspidate 
lobes,  the  notch  wide.  (i.  62.)  L.  1-1570" 
to  1-1483"  ;  B.  1-1813"  to  1-1088".  =  P. 
hexactis  (Hass.).     G.B.,  G. 


OF  THE  PEDIASTPvE^. 


755 


P.  Boryamim  (Menegli.).  —  Cells  ar- 
ranged in  one  or  more  circles  round  one 
or  two  central ;  the  inner  variable,  gene- 
rally concave  at  one  side,  the  outer  taper- 
ing into  two  long  subulate  jioints,  the  notch 
narrow.  L.  1-2083"  to  1-1633";  B. 
1-2733"  to  1-2222".  (i.  59,  60,  61,  68, 
69,  microgonidia.)  =  Blicrasterias  JBory- 
ana  (Elir.),  P.  suhuUferum  (Kg.),  P.  cru- 
ciatum  (Kg.).     G.B'.,  L,  F.,  G.,  U.S.A. 

P.  ellipticum  (Hass.).  —  Cells  A'arying 
in  number  and  arrangement ;  outer  cells 
suddenly  contracted  into  two  short,  cylin- 
drical, obtuse  processes.  L.  1-1754"  to 
1-906"  ;  B.  1-1515"  to  1-1020".  /3,  pro- 
cesses of  the  lobes  truncato-emarginjite. 
=  3Iic)'osterias  elliptica  (Ehr.),  P.  vagum 
(Kg.),  P.  constrict um  (Hass.,  Kg.)?  P-  ^^- 
dentulatum  (Braun).    G.B.,  I.,  G.,  U.S.A. 

P.  angulosuni  (Menegh.).  —  Cells  ar- 
ranged in  one  or  more  circles  round  one 
central,  the  inner  cells  roundly  angular, 
the  outer  obliquely  truncate,  emarginate, 
the  subdivisions  not  tapering  into  rays. 
L.  1-2732" ;  B.  1-1942".  =  Micrasterias 
angulosa  (Ehr.).     G.B.,  R,  G. 

3  *  Outer  cells  with  only  one  attenuated 
lobe  (Monactinus). 

P.  simplex  (Meyen). — Cells  eight,  in  a 
single  series  surrounding  a  central  vacant 
interval,  narrow-ovate  or  lanceolate,  very 
gi'adually  tapering,  acimiinate,  approxi- 
mate only  at  their  hases.  =  3Ionactinus 
mnplej:  (Kg.),  M.  simplex  et  acutangulus  '  (i.  46,  47,  48).     G. 


(Corda),  3/.  octonarius  (Bail.)  ?     F.,  G., 

U.S.A.     There  seems  to  us  to  be  some 

doubt  as  to  the  absolute  distinctness  of 

this  and  P.  gracile  (Braun),  as  it  is  pos- 

j  sible  the  four  deeply  bipartite  external 

I  cells  of  the  latter  may  have  been  mis- 

j  taken  for  eight  simply  attenuated  cells 

i  as  described  for  P.  simplex  (Meyen). 

j      P.  duodenarium  (Bailey,  sp.). — Inner 

I  cells/o«/-,  somewhat  triangular,  enclosing 

I  a  central,  quadrate  vacant  interval,  and 

j  four  broadly  lanceolate  vacant  intervals 

I  between  them  and  the  outer  series,  to 

t  which  they  are  united  by  their  terminal 

angles  ;    outer   cells    twelve,   subovate, 

:  truncate  below,  much    attenuated,   acu- 

;  minate.  =  Monactinus  duodenarius  ( Bail. ) . 

I  U.S.A. 

!      P.  ovatum  (Braun). — Cells  ovate,  ter- 
1  minating  in  a  long,  acute  point,  granu- 
late, arranged  in  tv\^o  series,  inner  three, 
I  outer  ten.=Asterodictyon  ovatum  (Ehr.), 
i  Monactinus  ovatus  (Kg.).     G. 
:       P.  Triangulum  (Braun). — Cells  trian- 
gular, smooth,  arranged  in  three  series, 
the  centre  vacant.    Asterodictyon  Trian- 
gulum (Ehr.)  =  3Io)iactinus  I'riangulum 
(Kg.).    G. 

4*  Oute?'  cells  not  lobed  (Anomopedium). 

P.  integrum  (Niig.). — Frond  irregidar, 
cells  rounded  or  bluntly  angular ;  outer 
cells  not  emarginate,  generally  possessing 
externally  two  short  mucro-like  spines 


Genus  CCELASTBUM  (Niig.). — Frond  or  family  hollow,  globular  or  sub- 
cubical,  composed  of  polygonal  (or  spherical)  cells  united  in  one  layer  into  a 
hollow  clathrate  net-lihe  family,  the  cells  drawn  out  on  the  exterior  into  one 
or  more  lobes,  or  simply  spherical ;  propagating  by  the  segmentation  of  the 
cell-contents  into  a  definite  number  of  portions  which  become  arranged  into 
a  hollow  young  frond  resembling  the  parent,  ultimately  set  free  by  the 
bursting  of  the  parent- cell. 


Ccelasthum  sph^ricum  (Nag.).  — 
Fronds  spherical  or  oval  ;  cells  hex- 
agonal, dra^^Ti  out  externally  into  a 
blunt  cone,  interstices  5-6-angular.  (i. 
49,50,51.)     G. 

Ccubicum  (Nag.). — Frond  subcubical. 


cells  hexagonal,  drawn  out  externally 
into  two  short  truncate  projections,  in- 
terstices quadrangular,    (i.  54, 55. )     G. 

C.  microporus  (Nag.). — Frond  globu- 
lar, ceUs  exactly  spherical,  interstices 
minute.     G. 


Genus  SORASTRUM  (Kg.). — Frond  or  family  solid,  globular,  composed  of 
cuneiform  or  cordate  cells,  somewhat  compressed  and  united  into  globular 
families,  their  narrow  ends  meeting  in  the  centre  and  outwardly  emarginate 
or  divided.     Propagation  unknown. 


SoRASTRUM  sjnnidosum  (Nag.). — Ex- 
ternal margins  of  the  cells  dilated, 
slightly  emarginate,  the  rounded  angles 
furnished  each  with  two  minute,  acute. 


subulate  spines,    (i.  56,  57,  58.)     G. 
S.  echinatum  (Kg.).  —  External  mar- 


gins of  the  cells  deeply 
divisions  subulate.     G. 


bifid,  the  sub- 
3c2 


75Q  SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 

Sub-group  DIATOMEJE  or  DIATOMACE.E. 

(Page  31,  Plates  IV.  to  XYII.  and  part  of  II.) 

[For  reference  to  tlie  species  figured  in  this  work,  see  Index  of  Diatornace£e 

illustrated.] 

Frustules  or  cells,  either  simple  or  pseudo -unicellular  by  complete  separa- 
tion, or  united  in  tablets  or  filaments,  fm-nished  with  a  sculptured  siliceous 
coat  in  three  portions,  a  median  one  (connecting  zone)  and  two  lateral  ones 
(valves)  united  by  distinct  sutures ;  internal  substance  yellowish-brown 
(rarely  olive-brown) ;  reproduction  by  conjugation  and  subsequent  formation 
of  sporangia. 

The  general  histoiy  of  the  Diatomacese  has  been  so  fully  treated  of  in  the 
first  part  of  this  work  (p.  31)  that  it  is  here  only  necessary  to  explain  some 
teiTQS  used  in  the  descriptions. 

The  Diatomaceae  differ,  in  several  respects,  so  widely  from  acknowledged 
Alga?,  that  in  our  opinion  ihej  maj^  be  regarded  rather  as  an  order  related  to 
the  Algse  than  as  a  family  belonging  to  them. 

The  siliceous  covering  is  composed  of  three  portions.  The  central  one  is 
sometimes  called  "connecting  membrane"  and  "cingulum;"  we,  however, 
prefer  Professor  Amott's  term,  "  connecting  zone,"  as  less  likely  to  mislead. 
The  lateral  or  junction  surfaces  correspond  to  the  septa  of  a  Confeiwa,  and  are 
called  valves. 

The  late  Professor  Smith  considered  the  central  portion  unessential  and 
produced  onty  preparatory  to  self-fission.  "VVe,  on  the  contrary,  regard  it  as 
of  great  importance,  and  quite  unkno^Ti  in  the  true  Alga).  It  is  conspicuous 
in  the  conjugating  and,  consequently,  matm-e  frustules ;  and  we  think  the  con- 
clusion illogical  that  it  has  no  sj'stematic  value  because  obscure  in  newly- 
formed  frustules.  It  is  evidently  essential  in  Diatoms  with  flat  valves,  since 
otherwise  there  could  be  no  cavity  to  contain  internal  matter. 

We  use  the  term  "  front  view "  to  denote  that  position  of  the  frustide 
when  the  connecting  zone  is  fully  presented  to  the  e^^e,  and  "  side  view " 
when  the  centre  of  the  valve  is  in  a  similar  position.  A\Tien  we  speak  of  the 
"  valve,"  unaccompanied  by  a  qualifying  epithet,  it  must  be  understood  as 
identical  with  "  side  view." 

''Longitudinal"  means  in  the  direction  of  the  connecting  zone,  and 
''  transverse  "  in  the  opposite  direction  uniting  the  valves.  When  so  applied 
to  the  frustule  of  a  Diatom,  these  terms  acquire  a  meaning  exactly  the  reverse 
of  that  in  which  they  are  used  when  applied  to  the  joint  of  a  Confei-va  and 
the  frond  in  the  Desmidie£e.  For  example,  the  frustnle  in  some  Diatoms  and 
the  frond  in  Closteriiun  are  both  described  as  longitudinally  lunate,  whilst 
they  are  really  extended  in  opposite  directions :  unless  the  change  in  the 
meaning  of  the  terms  be  remembered,  an  idea  of  similarity  will  be  conveyed 
which  is  altogether  erroneous. 

The  valves  are  sculptured,  cellulose,  or  striated ;  the  apparent  absence  of 
striai  in  some  instances  may  be  accounted  for  by  their  extreme  delicacy 
placing  them  beyond  the  reach  of  our  instruments,  since  the  greater  the 
penetration  of  the  object-glass,  and  the  more  perfect  the  illumination,  the 
greater  is  the  number  of  species  found  to  possess  them.  AMien,  therefore,  we 
use  the  terms  "  smooth  "  and  ''  very  smooth  "  in  definitions  taken  from  foreign 
works,  they  must  be  understood  to  mean  only  that  the  stride  were  too  fine  to 
be  ascertained  by  the  microscope  of  the  describer. 


OF  THE  DIATOMACEJE.  757 

The  word  "transverse"  is,  for  the  sake  of  bre\'ity,  omitted  before  strise  in 
the  definitions,  but,  unless  the  contraiy  be  expressed,  it  must  always  be 
understood. 

A\Tien  the  frustules  are  lunate  or  curved,  the  convex  margin  is  called  the 
dorsimi  and  the  opposite  the  venter. 

We  have  not  mentioned  the  Sporangia  in  the  generic  and  specific  descrip- 
tions, because  the  examples  recorded  are  too  few,  and  that  condition  is  too 
seldom  met  ^vith  to  be  practically  useful.  With  respect  to  the  general 
history  of  the  Diatomaceae,  the  importance  of  Mr.  Thwaites's  discoveries  can 
scarcely  be  overrated  (see  p.  61).  We  consider  it,  however,  desirable  to  point 
out,  that  whilst  the  similarity  of  their  conjugating  process  to  that  of  the 
Desmidicae  affords  a  powerful  argument  in  support  of  the  vegetable  natiu-e  of 
the  Diatomacea),  the  widely  different  characters  of  their  sporangia,  not  merely 
in  form  but  in  subsequent  changes,  furnish  UTesistible  evidence  of  the  pro- 
priety of  separating  the  Desmidiese  from  the  Diatomaceae.  The  resemblance 
of  the  reproductive  bodies  in  the  latter  to  the  parent  frustules,  and  their  con- 
tinuous growth  and  increase  by  self- division,  is  so  unlilie  what  we  find  in 
the  sporangia  of  the  Desmidieae  and  Conjugatae,  as  to  appear  more  like  an 
*'  alternation  of  generations  "  than  examples  of  true  sporangia. 

The  fii'st  attempt  at  a  scientific  arrangement  of  the  Diatomaceae  was  by 
C.  A.  Agardh  in  the  '  Conspectus  Criticus  Diatomacearum.'  He  distributed 
them  into  three  families — CjTabeUeae,  Styllarieae,  and  Fragilarieae,  according 
to  the  form  of  their  frustules.  He  considered  that  lq  each  family  the  frus- 
tides  might  be  free,  stipitate,  united  into  a  filament,  or  enclosed  in  a  frond. 
This  system  was  greatly  extended  and  improved  by  Professor  Kiitzing  ;  and,  as 
we  believe  his  arrangement  (p.  101)  is  the  best  and  most  natural  yet  pro- 
posed, we  have  used  it  in  this  work,  admitting,  however,  some  judicious 
alterations  proposed  by  Meneghini  and  others.  It  is  true  we  do  not  meet 
with  examples  of  the  four  conditions  in  each  family ;  but  they  may  fairly  be 
anticipated  to  occur,  and  their  absence  regarded  as  lacunae  likely  to  be  filled 
up  by  futiu'e  discoveries.  We  have  thus  brought  together  nearly  allied  genera ; 
for  it  is  often  difiicult  to  distinguish  a  Eunotia  from  a  Himantidium,  a  Tri- 
ceratium  from  an  Amphitetras,  a  Cymbella  from  a  detached  Cocconema,  and 
an  escaped  frustule  of  CoUetonema  from  a  Navicula.  The  arrangements  of 
Ehrenberg  and  Smith  we  regard  as  far  inferior, — separating,  as  they  do,  such 
nearly  allied  forms.  Indeed  the  fame  of  those  eminent  observers  must 
depend  on  their  intimate  knowledge  of  genera  and  species,  and  on  their 
definitions  being  superior  to  those  of  their  predecessors,  and  not  on  their 
primary  divisions.  We  feel  persuaded  that,  but  for  his  lamented  death, 
Professor  Smith  would  have  been  led  by  increased  acquaintance  with  the 
Diatomaceae  to  modify  his  views  in  that  respect  in  a  future  edition  of  his 
valuable  and  beautiful  work  on  the  British  Diatomaceae. 

ANALYSIS  OF  THE  FAMILIES  OF  DIATOMACE^. 

A. 

{Yalves  with  central  nodule  and  median  longitudinal  line  B. 

,,       with  umbilicus  or  pseudo-nodule  and  radiant  lines  or 
ceUules 12 

„       without  a  central  nodule     2 

2  r  Frustules  in  side  view  lunate  or  arcuate 3 

'[  .,  ,,  with  symmetrical  margins    6 

3  I  Valves  dissimilar Striatelle.e. 

■\      „       similar 4 

A   f  Valves  cellulose,  without  transverse  striae ANGULiFERiE. 

'1      „      not  cellulose 5 


'5S  SYSTEMATIC  HISTORY  OF  THE  INFTJSOEIA. 

P   [  Valres  with  pervious  costre  or  striae Eunotie.e. 

'^' \  „  a  longitudinal  line  or  keel Surirelle^. 

P   f  Frustules  cuneate  in  the  front  view 7 

I         ,,         not  cuneate  in  the  front  view    11 

f.  I  Frustules  free ;  valves  with  aire Surirella. 

'■  I  ,,         attached  or  united  in  filaments ;  valves  without  alse  ,. .  8 

c  j  Valves  dotted,  dots  not  forming  striae   Eucampia. 

„       not  dotted,  or  the  dots  arranged  in  transverse  lines 9 

'  Frustides  radiating  from  a  common  centre ;  valves  obovate  or 

clavate     10 

,.  not  radiant ;  valves  with  symmetrical  ends Fragilarie^. 

'  Frustules  in  front  ^dew  \^dth  longitudinal  vittiB  Licmophorej:. 

„                   ,,            without   longituduiai  vittse   (costse   per- 
vious)   MERTDIE.E. 

"  Connecting  zone  (annvdate)  with  imperfect  internal  septa Striatelle.e. 

,,  „      without  internal  septa    12 

{  Lateral  view  witli  3,  or  more,  angles  or  lobes  Angulifer^e. 

12.  s        „         ,;      circular  17 

[       ,,         ,,      neither  angular  nor  circular 13 

(Valves  not  conspicuous  in  front  view,  which  is  mostly  longer 
than  broad 14 

„      compressed,  inflated,  conspicuous  in  front  view,  which  is 
mostly  broader  than  long 15 

^  ,   J  Valves  with  a  longitudinal  line Surirelle.e, 

[      ,,       without  a  longitudinal  Hne     Fragilarie.e. 

-J ^    r  Valves  in  front  view,  rectangular,  with  transverse  capitate  vittre  .  Terpsinoee. 

^•^^  I       „  „  with  produced  angles,  processes,  or  spines  16 

1  f,  J  Valves  cellulose,  symmetrical Biddulphie.e. 

I      „       not  cellulose,  mostly  dissimilai* Ch.etocerke. 

{Frustules  saddle-shaped ;  valves  mostly  with  longitudinal  blank 
space    Campylodiscus. 
„         not  saddle-shaped ;  central  blank  space  (if  any)  orbicular  18 

-.Q   (  Valves  cellulose    19 

°'  {      „      not  cellulose Melosire.e. 

{Frustules  simple  ;  lateral  view  more  conspicuous  than  front 20 

„         either  imited  into  filaments  or  front  view  broader  than 
lateral Melosire.e. 

90  i  Valves  fmiiished  with  projecting  processes  Eupodisce,e. 

I      „       without  processes,  but  sometimes  vrith  minute  teeth  Coscinodisce.e. 

B. 

rt,    f  Only  one  valve  with  a  central  nodule   22 

\  Botii  valves  with  central  nodules  23 

i^,^   r  Frustules  adnate,  not  genuflexed   Coccoxeide.e. 

"*"  i         „         not  adnate  (often  stipitate),  genuflexed    Achnanthe^. 

(Frustules  cuneate  in  front  view ;  valves  usually  with  dissimilar 
ends GoMPHONEME^. 
,,          not  cuneate;  valves  with  symmetrical  ends    24 

o  -    r  Median  line  rib-like  and  distinct ;  nodides  distinct 25 

I  ,,  not  rib-Kke ;  nodides  mostly  obscure  2  > 

Side  view  kmate ;  nodide  mostly  excentric  26 

,,  not  lunate  (rarely  lunately  curved) ;  nodule  central ...  Navicule.e. 

op    r  Valves  venti'icose,  stride  not  decussating    Cymbelle-b. 

I      ,,       not  ventricose,  striae  decussating    Toxonidea. 

C. 

Individuals  of  one  piece,  with  radiating  spines    Actinisce.e. 

Families. 
*  Valves  without  a  central  nodule. 
Eunotiea?.      Meridieae.      Licmophoreag.      Fragilarieoe.      Synedi'ea?.     Smdrellea^.     Stria- 
tellese.    Terpsinoese.   Biddulphieae.    Angulifereae.   Eupodisceae.    Coscinodisceae.   Melosirese. 
Chaetocerca\ 

2*  Vah'CH.  unth  a  median  line  and  a  central  nodule. 

C"occov.ddca\     Admanthoa\     Cymbelleae.     Gomphonemeae.     Naviculese. 


Actinisceae, 


OP  THE  EUNOTIE^. 


759 


FxVMILY  I.— EUNOTIE.^. 

Frustiiles  free  or  adnate,  in  lateral  \'iew  lunate  or  arcuate,  with  transverse 
striae  or  costoo,  not  interrupted  by  a  central  nodule  or  longitudinal  line.  The 
essential  characters  of  this  group  are  the  lunate  form  of  the  frustules  in  the 
lateral  \dew,  and  the  stria?  being  continuous  across  the  valve,  and  not  inter- 
rupted by  a  longitudinal  line.  It  is  easily  distinguished,  except  from  some 
species  of  Synedi'a,  which,  however,  are  Hnear-ciurved  rather  than  lunate, 
and  usually  have  an  evident  though  faint  longitudinal  line.  Ampliipleura 
inflexa,  which  in  form  more  nearly  resembles  Eimotia,  has  a  longitudinal 
line  passing  down  the  middle  of  the  lateral  valves.  The  Eunotieae  have  one 
siuface  of  their  connecting  zone  flat  or  concave  and  the  opposite  one  convex, 
the  convexity  being  usually  greater  than  the  conca\ity.  The  lateral  portions 
or  valves  are  either  flat  or  convex ;  in  the  former  case  they  do  not  appear  in 
the  front  view,  and  the  frustule  appears  quadi'ilateral ;  in  the  latter,  on  a 
front  view,  they  have  an  oval  form.  Like  most  Diatomaceae,  the  connecting 
zone  has  two  puncta  at  each  end. 


Genus  EPITHEMIA  (K.). — Frustules  Innately  curved  in  lateral  view,  and 
furnished  ^nth  transverse  internal  ribs  (canals,  Sm.) ;  usually  adnate  by  the 
flat  or  concave  surface  of  the  connecting  zone,  and  not  by  one  of  the  lateral 
valves,  like  Cocconeis.  The  lateral  view  has  strongly-marked  transverse  lines, 
which  Mr,  Smith,  in  his  beautiful  work  '  The  British  Diatomacese,'  calls 
canaliculi.  We  consider  them  internal  ribs ;  in  fragments  it  is  b}^  no  means 
difiicult  to  see  them,  as  they  give  a  dentate  appearance  to  the  margin ;  their 
form  is  somewhat  triangular,  but  we  are  unable  to  detect  any  internal  cavity 
or  canals.  Mr.  Smith,  however,  may  have  used  microscopes  of  larger  angular 
aperture  and  higher  magnifying  powers  than  we  employed.  Besides  these 
ribs,  the  valves  have  transverse  striae  or  punctated  lines.  The  adnate  fi^us- 
tules  and  strongly-marked  ribs  distingiiish  Epithemia  from  Eunotia  and 
Himantidium.  In  the  front  view  the  ends  of  the  ribs  frequently  produce  a 
beautiful  beaded  appearance.  These  beads  form  two  longitudinal  lines,  and 
are  more  or  less  remote  from  the  margins,  according  to  the  convexity  of  the 
lateral  valves.  They  are  frequently  more  numerous  on  one  side  than  on  the 
other,  and  are  not  all  equidistant,  even  in  the  same  series. 


*  Front  vieiv  gihhous  at  the  centre, 
costcejine. 

Epithemia  gibha  (E.,K.). — Front  \dew 
elongated,  linear,  inflated  at  the  centre 
and  ends.  KB.  p.  33,  t.  4.  f  22.  =  Na- 
vicula  gihba,  E  Inf.  p.  184;  Ennotia 
gtbha,  EA  &  M,  many  figm'es.  Fresh 
water,  Coimnon.  Ehrenberg  gives  about 
100  habitats  in  Em^ope,  Asia,  Australia, 
Africa,  and  America,  (xii.  27.)  Striss  36 
in  _ -001";  costae  15  in  -OOl".— Distin- 
guished by  its  elongated  frustules,  fine 
striae,  and  dilated  ends;  but,  from  its 
nearly  straight  side-view,  its  proper  genus 
may  be  overlooked. 

_  E.  ventricosa  (K.). — Front  view  ellip- 
tic, oblong,  with  gibbous  middle ;  valves 
arcuate,  with  gibbous  dorsum  and  atte- 
nuated, acute,  somewhat  incurved  Puds  ; 
striae  fine.     KB.  p.  35,  t.  30.  f  9 :  SBD. 


i.  pi.  1.  f.  14.    Fresh  and  brackish  water. 
Europe. 

E.  cmgidata  (Perty). — Dorsum  turgid, 
sloping  to  the  obtuse  ends ;  venter  con- 
cave at  the  centre,  striae  about  12  in 
1-1200".  Rab  Diat.  p.  18,  t.  1.  f.  18.  = 
Eunotia  Jastrahensis,  EM.  pi.  8.  1.  f .  3  ? 
Switzerland.  Fossil.  Hungary.  Ac- 
cording to  the  figures,  the  frustules 
are  gibbous  or  rhomboid  in  the  front 
view. 


2*  Front  view  with  marginal  bead-like 
dots  formed  hy  the  capitate  ends  of  the 
costcB  (  =  Cystopleura,  Breb.). 
E.  Argus  (E.,  K.).  — Front  view  rect- 
angular, with  conspicuous  ocelli  tenni- 
nating  the  stalk-like  costae,  and  having 
distinct  strire  interposed  between  them. 
KB.  p.  35,  t.  20.  f.  55.  =  Eunotia  Argus, 
EA.  p.  125,  &  M.  1. 15  A,  f.  59.     Europe, 


'GO 


SYSTEMATIC  HISTORY  OF  THE  IXFUSOEIA. 


Asia,  Aii-tralia,  and  America,  (xv.  11.) 
\'alve  Innately  ciu'ved.  Sporangial  frus- 
tules  %\-ith  somewhat  angular  dorsum. 
A  common  species,  easily  recog-nized  by 
the  distinct  •  marginal  stride  intei-posed 
between  the  rather  distant,  conspicuous 
bead-like  ocelli. 

E.  ulpcstris  (K.). — Front  view  rectan- 
gidar  or  subcuneate,  with  conspicuous 
marginal  ocelli  and  interposed  strice ; 
valves  narrow,  arcuate,  \\dth  the  romided 
apices  scarcely  a  little  recurved.  KB. 
p.  84,  t.  5.  f.  16.  =  ^5".  ostrantina,  Rab  Diat. 
p.  11),  t.  1.  f.  29?  France,  England, 
(xiii.  8.)  AVe  are  unable  to  distinguish 
this  species  from^.  Ar(/m ;  for  we  believe 
that  the  subcuneate  front  view  is  an 
accidental  variation,  and  in  specimens 
from  M.  de  Brebisson  we  find  that  cha- 
racter by  no  means  constant.  Striae  are 
interposed  between  the  ocelli,  as  in  JiJ. 
Atu/iis,  and  are  nearly,  if  not  quite,  as 
distant  as  in  that  species  ;  and  we  doubt 
whether  recur\ed  extremities  of  the 
valves  are  not  sometimes  found  in  both. 

E.  reticulata  (Nag.). — Front  viewrect- 
angidar,  margins  with  stronger  capi- 
tate and  intermediate  finer  ones ;  valves 
slightly  curved,  the  obtuse  ends  some- 
what attenuated ;  strine  strong,  3  to  5  in 
1-1200" ;  the  interstices  regularly  reticu- 
lated, veined,  margins  finely  transversely 
striated.    KSA.  p.  869.    Switzerland. 

E.  loiu/icoDiis  (E.,  S.). — Front  \'iew 
subrectangidar,  with  conspicuous  mar- 
ginal ocelli  and  strife,  as  in  JE.  An/us ; 
valves  elongated,  curved,  with  obtuse 
ends  and  slightlv  angular  dorsum. 
8B1).  pi.  ;iO.  i.  247.  =  Einwtia  lomji- 
cornis,  EM.,  several  figures.  Europe, 
Asia,  and  America,  (xv.  0-9).  Costae 
strong,  alternating  with  striated  spaces. 
Perhaps  a  sporangial  state  of  E.  An/us. 

E.  oceUata  (P].,  K.). — Front  view  bar- 
rel-shaped, with  conspicuous  marginal 
ocelli  and  interposed  strijie ;  valves  lu- 
nately  curved,  with  roimded  apices,  KB. 
p.  U,  t.  29.  f.  57 ;  SBD.  pi.  1.  f.  6.  =Eu- 
Hotia  ocelldta,  E.  Fresh  water.  Europe 
and  America,    Fossil,    Greece. 

E.  Ei((j(>)(ue  (S,), — Front  view  inflated, 
witli  truncate  extremities ;  valves  lunate, 
with  straight,  truncate  extremities  ; 
costac  distinct,  8  in  -001";  oceUi  con- 
spicuous ;  stricG  32  in  -OOl".  S  An. 
.Jan,  1857,  p,  7,  pi,  1,  f.  1,  Freshwater. 
Biarritz,  France.  The  nearest  allies  of 
tills  species  are  E.  prohoscidm  and  E. 
Sorex.  It  may  bo  distinguished  from 
the  first  by  its  distinct  ocelli,  and  from 
the  second  by  its  conspicuous  cosUe  and 
their  areola-iike  interspaces,    S. 


E,  comta  (E,), — Small ;  valves  curved, 
with  regularly  convex  dorsum  and 
rounded  ends ;  strife  strong  and  gi-a- 
nidar,  =  Eunotia  comta,  EA.  1840,  &  M. 
pi.  6.  2.  f.  17  e,f.  Fossil.  Greece.  We 
are  not  certain  whether  this  and  the  next 
species  are  correctly  placed  in  the  ocel- 
lated  section. 

E.  Hellenica  (E.).  —  Valves  long, 
cur^-ed,  with  regularly  convex  dorsimi 
and  rounded  ends ;  costjTe  strong,  4  in 
1-1200",  having  very  delicate  striae  in- 
tervening between  i\\^VL\.=  Eunotia  Hel- 
lenica, EA.  1840,  &  M.  pi,  6.  2.  f.  17  a,  b. 
Fossil.     Greece. 

3  *  Castes  not  capitate. 

E.  constricta  (Breb.).  —  Front  view 
elliptical,  slightly  constricted  at  the 
middle ;  valve  semilunate,  with  8  distinct 
costa3  in  -001".  SBD.  vol,  i.  p.  14,  pi. 
30.  f,  248.  Brackish  water.  France  and 
England,     Strife  30  in  -001".     S. 

E.  maryaritifera  (Rab.). — Front  view 
barrel-shaped,  with  truncate  ends  and 
striated  margins ;  valves  with  three  dor- 
sal undulations  and  rounded  ends ;  costae 
4  to  5  in  1-1200";  bordered  by  puncta. 
Rab  Diat.  p.  17,  pi.  1.  f.  32.     Persia. 

E.  Musculus  (K.). — Front  view  sub- 
orbicidar ;  valves  lunate,  with  very  con- 
vex dorsum,  concave  venter,  and  taper- 
ing acute  apices;  costae  distinct.  KB. 
p.  33,  t.  30.  f.  6;  SBD.  pi.  1.  f.  10.  = 
Eunotia  Sphcerula,  EM.  pi.  8.  1.  f.  6  ? 
Brackish  water.  Em-ope,  Asia,  Africa, 
and  America,  (xin.  18.)  Striae  40  in 
•001".     S. 

E,  rupestris  (S.). — Front  view  elliptic 
or  elliptic-lanceolate  ;  valves  semilan- 
ceolate,  tapering  to  the  subacute  apices ; 
costae  distinct ;  striae  faint,  40  in  -001". 
SBD,  vol.  i.  p.  14,  pi.  1.  f.  12.  E.  cjihhe- 
rula,  KB.  t.  30,  f,  3 ;  KA.  p.  3.  =  E. 
Westermanni,  SBD.  vol.  i.  p.  14,  pi.  1. 
f.  11,  Fresh  or  brackish  water.  Europe 
and  America. 

E.  quinquccostata (Rab.). — Valve  semi- 
lanceolate,  M'ith  obtuse  ends,  and  five 
somewhat  converging  costae.  Rab  Diat. 
p.  18,  t.  1.  f.  35.     Germany. 

E.  Hyndmani  (S.). — Front  view  ven- 
tricose  witJi  truncate  ends  ;  valves  stout, 
lunately  curved,  with  rounded  apices; 
strifie  moniliform,  IG  in  -001";  costaB  in- 
conspicuous, SBD,  vol.  i,  p.  12,  pi.  1.  f.  1. 
=  Eunotia  Luna,  EM.  pi.  15  a.  f.  58. 
Britain,     Large ;  valve  not  recurved. 

E.  Westermanni  (E,,  K,),— Front  view 
elliptic  ;  vah  es  semilunate,  with  turgid, 
coii\(;x  dorsum  gradually  attenuated  to 
the  rather  obtuse  not  prominent  apices ; 


OF  THE  -RVSOTIEJE. 


761 


stripe  scarcely  converg-ing,  7  or  8  in 
1-1200".  KB.  p.  28,  t.  30.  f.  4.  =  JSu- 
notia  Westennanni,  E  Inf.  p.  190,  &  M, 
many  figures.  Europe,  Asia,  and  Ame- 
rica, (iv.  2  ;  IX.  157.)  In  Ehrenberg's 
figures  the  frustules  are  large,  the  stout 
valves  have  the  obtuse  apices  somewhat 
produced  and  recurved,  and  the  inter- 
stices of  the  costse  furnished  with  dotted 
lines. 

E.  (jihherula  (E.). — Front  view  elliptic, 
with  slightly  produced  apices;  valves  | 
with  gibbous  dorsum,  slightly  concave  ' 
venter^  and  attenuated,  recurved  apices ; 
striae  converging,  83  in  -001".  =I^unotia  \ 
gihhei'ula,  EA.  p.  125,  &  M,  nimierous  \ 
figures.  =  E.  Sorex,  KSA.  p.  1 ;  SBI).  I 
vol.  i.  p.  18,  pi.  1.  f.  9.  Fresh  or  brackish  ; 
water.  Common.  Europe,  Asia,  Aus-  j 
tralia,  Africa,  and  America.  Costae  in-  , 
conspicuous.  j 

E.  Saxonica  (K.)- — Minute ;  fi'ont  view  | 
rectangular ;  valves  Innately  cm'ved,  at-  | 
tenuated,  with  obtuse  not  recm'ved  ends ; 
striae  sn]3Converging,  6  to  7  in  1-1200".  ; 
KB.  p.  35,  t.  5.  f.  15.  Italy  and  Ger-  ; 
many.     1-840".  "  | 

E.  Textricula  (E.,  K.). — Valve  linear,  | 
limately  cm-^'ed,  with  roimded  ends ; 
costae  stout,  distant ;  interspaces  with 
series  of  longitudinal  striae.  KB.  p.  85, 
t.  29,  f.  53.  =  Eunotia  Textricula,  EA. 
p.  126,  &  M,  several  figures.  Ern'ope, 
Asia,  Australia,  Africa,  and  America. 
Small ;  ends  not  recmTed. 

E.  Zebra  (E.,  K.). — Front  view  sub- 
linear;  vahes  semilunate,  with  convex 
dorsum,  straiglit  venter,  and  very  obtuse, 
slightly  prominent  apices;  costae  con- 
vergent, 5  to  7  in  -001".  KB.  p.  34, 
t.  30.  f.  5 ;  SBD.  pi.  1.  f.  4.  =  Eunotia 
Zebra,  E.  Em'ope,  Asia,  Africa,  and 
America.     Striae  33  in  -001".     S. 

E.  zehrina  (E., K.). — Elongated ;  valves 
with  evenly  convex  dorsimi,  gi-adually 
decun-ent  into  the  obtuse,  constricted 
apices;  interspaces  dotted.  KB.  p.  34. 
=  Eunotia  zehrina,  EA.  p.  126,  &  M, 
several  figm-es.  Asia,  Australia,  Ame- 
rica, and  Europe. 

E.^Mr</<V/rt(E.,K.). — Large  ;  front  view 
linear  or  slightly  dilated  at  the  middle  ; 
valves  curved,  mth  the  slightly  convex 
dorsum  gTadually  attenuated  to  the  trun- 
cate apices,  which  are  neither  prominent 
nor  recurved ;  striae  diverging,  8  or  9  in 
1-1200".  KB.  p.  34,  t.  5.  f.  l-i.  =  Eunotia 
turgida,  E  Inf.  t.  14.  f.  5.  Em'ope,  Asia, 
and  America,  (iv.  1 ;  ix.  159-161.) 

E.  f/ranulata  (E.,  K.). — I^arge  ;  front 
view  linear  or  linear-oblong ;  valves 
slender,  slightly   arcuate,  with   obtuse. 


recurved  apices;  striae  moniliform ;  costae 
distinct.  KB.  p.  35,  t.  5.  f.  20.  E.  Faba, 
KB.  p.  36,  t.  5.  f.  21.  =  Eunotia  c/rami- 
lata,  E  Inf.  p.  191,  t.  21.  f.  20  =  E2?itlw- 
mia  turgida,  SBD.  vol.  i.  pi.  1.  f.  2.  Eu- 
rope, Asia,  Africa,  and  America. 

E.  Vertagus  (K.). — Large ;  front  view 
sublinear,  gradually  dilated  at  the  mid- 
dle; valves  slender,  arcuate,  with  roimded, 
reflexed  apices  ;  costae  converging,  10  in 
1-1200"  ;  strife  punctate.  KB.  p.  36, 
t.  30.  12  =  E.  granulata,  SBD.  vol.  i. 
t.  1.  f.  3.  Fresh  water.  Europe.  Re- 
sembles the  last,  but  the  valves  are  far 
more  slender. 

E.  Lihrile  (E,,  K.).— Large ;  fi'ont  view 
rectangular ;  valves  arcuate,  with  con- 
cave venter,  dorsum  evenly  convex  at 
the  middle,  suddenly  decreasing  towards 
the  obtuse,  slightly  revolute  apices ;  in- 
terspaces between  the  costae  dotted. 
KB.  p.  35,  t.  29.  f.  45.  =  Eunotia  Lihrile, 
E  Amer.  p.  126,  t.  3.  1.  f.  38.  Asia, 
Africa,  and  America,  (xn.  24,  25.) 

E.  Porcellus  (K.). — Large ;  front  view 
linear,  seven  times  as  long  as  broad ; 
valves  with  convex  dorsimi,  concave 
venter,  and  truncate  reflexed  ends ; 
striae  converging,  11  in  1-1200".  KB. 
p.  34,  t.  5.  f.  18,  19.  Fossil.  San  Fiore. 
(xm.  12.)     1-240"  to  1-216". 

E.  proboscidea  (K.).  —  Small ;  front 
view  rectangular  with  obtuse  angles  ; 
valves  with  gibbous  dorsum,  slightly 
concave  venter,  and  constricted,  obtuse, 
remarkably  recm^ed  ends ;  costae  con- 
spicuous, converging.  KB.  p.  35,  t.  5. 
f.  13  ;  SBD.  vol.  i.  p.  13,  pi.  1.  f.  8  ? 
Fossil,  Llineburg ;  Britain  ;  recent,  Jer- 
sey. Costae  5  or  6  in  1-1200".  British 
specimens  have  the  front  view  inflated, 
and  therefore  may  be  distinct. 

E.  P  marina  (Donkin).  — Dorsal  view 
rectangidar,  with  longitudinal  series  of 
pimcta  on  the  connecting  zone;  valves 
linear,  slightly  arcuate,  with  produced 
rosti-ate  apices;  costae  conspicuous;  in- 
terspaces punctated.  Donkin,  TMS. 
vol.  \^.  p.  29,  pi.  3.  f.  14.  Marine.  Eng- 
land. A  large  and  beautiful  Diatom, 
whose  genus  is  somewhat  imcertain.  It 
agrees  with  Amphora  in  having  the  lon- 
gitudinal rows  of  puncta  confined  to  the 
dorsal  sm-face,  whilst  in  the  form  of  its 
valves  it  resembles  some  species  of 
Nitzschia.  Costae  and  striae  11  in  -001". 
Donkin. 

Doubtful  and  insufficiently  knoum  species. 

E.   Electra  =  Eunotia    Electra,    EM. 

pi.  37. 3.  f.  3.     Fossil.     Prussia.     Valve 

semi  orbicular,  with  strong,  radiant  striae. 


762 


SYSTEMATIC  HISTOET  OF  THE  INFUSOEIA. 


E.  Lindiffii  (Rab.).  —  Minute  ;  front 
view  orbicular ;  costse  6  to  7.  Rab  Diat. 
p.  19,  pi.  1.  f.  20.     Bogota. 

E.  Sancti  Antomi  =  Eimotia  Sancti 
Antonii,  EM.  pi.  34.  5.  f.  7,  &c.  Ame- 
rica. Front  view  rectangular,  with 
conspicuous  marginal  capitate  striae; 
valves  obtusely  lanceolate,  straight,  with 
strong  transverse  costae.  Probably  a 
Denticula. 

E.  Beatorum= Eunotia  Beatorum,  EM. 
pi.  34.  5.  f.  8.  America.  Front  ^dew 
rectangTilar,  with  marginal  gland-like 
puncta.  According  to  Ehrenberg,  this 
species  is  allied  to  E.  Sancti  Antonii. 

E.  Lumda  =  Eunotia  Lunula.,  EM. 
pi.  33.  7.  f.  9,  &  pi.  33.  14.  f.  8.  Ehren- 
berg's  figures  dilfer  considerably.  The 
first  is  slightly  arcuate,  elongated,  with 
obtuse,  slightly  recurved  ends;  the  se- 
cond is  smaller,  lunate,  rapidly  tapering 
to  the  obtuse  ends.  Both  have  radiant 
costae  ^vithout  intermediate  dotted  lines. 

E.  mesoJepta  =  Eunotia  mesolepta,  EM. 
pi.  9. 1.  f.  26.^  Fossil.  France.  Valves 
elongated,  slightly  cm'ved,  with  attenu- 
ated middle,  and  conic  ends ;  costse  alter- 
nating with  dotted  striae. 

E.  mesogongyla  =  Eimotia  mesogorigyJa, 


EM.  pl._  9.  1.  f.  27.  Fossil.  France. 
Valves  linear,  elongated,  slightly  curved, 
with  gibbous  middle,  and  rounded  ends ; 
costse  alternating  with  dotted  striae. 

E.  ?  Fahti  (E.,  K.).— Valves  semioval, 
slightly  arcuate,  with  obtuse,  very  slightly 
recurved  apices,  and  9  moniliform  striae 
in  1-1200".  =  Eunotia  Faba,  EM.  Seve- 
ral figures.  Ehrenberg's  figure  seems  to 
us  rather  to  represent  a  Emiotia  than  an 
Epithemia. 

E. ?  cingiilata (E.,K.). — Small,smooth, 
with  convex  dorsimi  and  tumid  connect- 
ing zone.  KB.  p.  36.  =  Eunotia  ?  cm- 
gulata,  EA.  p.  126,  t.  2.  6.  f.  34.  North 
America.     Aldn  to  E.  gihherula,  E. 

E.  Cocconema  =  Eunotia  Cocconema, 
EM.  pi.  34.  7.  f.  1.  Canton.  Valve 
stout,  semilunate,  with  regularly  convex 
dorsum,  straight  venter  and  rounded 
ends,  strong  costae,  fine  intermediate 
striae,  and  a  longitudinal  blank  line. 

E.  Cistula  =  Eunotia  CistuJa,  EM. 
pi.  8.  1.  f.  5,  &c.  Asia.  Front  view  ob- 
long or  elliptic,  with  costate  margins ; 
valves  stout,  lunate,  with  obtuse  ends, 
strong,  radiating  costae,  and  a  blank 
longitudinal  line. 


Genus  EUNOTIA  (E.).  —  Fnistules  free,  in  fi^ont  view  qnadi'angular,  in 
lateral  view  Innate,  or  arcuate,  and  striated.  In  form,  Eunotia  is  allied  to 
Epithemia ;  bnt  the  lateral  snrfaces  of  the  frnstnles  are  merely  striated,  and 
want  the  conspicnons  costae  of  that  genus.  The  superior  margin  is  usually 
imdulated, — an  appearance  caused  by  transverse  depressions.  The  fi^ustules 
are  not  adnate,  and  in  the  front  view  do  not  appear  beaked. 

"We  believe  that  the  species  in  this  genus,  as  in  several  others,  have  been 
founded  upon  insufiicient  characters,  and  that  those  forms  which  diifer  only 
in  the  undulations  should,  as  Professor  Bailey  suggests,  be  regarded  as 
varieties.  As  this  work,  however,  is  intended  to  include  aU  generally 
admitted  species,  we  are  content  to  indicate  our  opinion,  the  correctness  of 
which  must  be  determined  by  futui'e  observations.  Kiitzing  and  Meneghini 
describe  the  transverse  section  as  trapezoidal,  and  regard  it  as  an  important 
generic  character ;  but  we  agree  with.  Professor  Smith  in  doubting  the  occur- 
rence of  such  a  form.  Several  species  of  Eunotia  have  been  found  by  Bailey 
and  Brebisson  united  into  short  bands  ;  and  unless  the  generic  characters  of 
Eunotia  and  Himantidium  can  be  strengthened,  it  will  become  necessary  to 
reunite  these  genera.  The  dorsal  elevations  in  Eunotia  and  Himantidium 
appear,  in  the  front  view,  transverse  darker  bands. 

rica.     Akin  to  E.  nodosa,  but  with  in- 
flated and  straight  apices.     E. 

E.  veyitralis  (E.).  —Valves  elongated, 


*  Dorsal  margin  of  valves  7iot  dentate. 

Eunotia  nodosa  (E.). — Valves  slightly 
arcuate,  with  inflated  centre  and  reflexed 
obtuse  apices.  ERBA.  1840,  p.  15,  &  M. 
pi.  15  B.  3.  f.  25.  Asia  and  America. 
Lough  Mourne  deposit. 

Fj.  Formica  (E.). — Valves  linear,  with 
inflated  centre  and  ends.  EA.  p.  126, 
&  M.  pi.  3.  4.  f.  18.   Australia  and  Ame- 


lineai",  curved,  with  tumid,  rounded 
apices,  and  gibbous  venter.  EA.  p.  126, 
&  M,  several  fio-ures.  Europe,  Asia, 
Africa,  and  America. 

E.  Luna  (E,). — Valves  linear,  Innately 
cui-ved,  with  simply  convex  dorsum, 
2-ibbous    venter,     and     obtuse     apices. 


OF  THE  EUNOTIE^. 


763 


ERBA.  1845,  p.  77,  &  M.  pi.  33. 12.  f,  13. 
Fossil.     Oregon. 

E.  Sima  (E.). — Valves  linear,  slightly 
curs^ed,  -wdtli  rather  concave  venter  j 
dorsum  suddenly  sloping  down  to  the 
produced,  acute,  reflexed  apices.  ER 
BA.  1845,  p.  77,  &  M.  pi.  33.  12.  f.  16. 
Fossil.     Oregon. 

E.  biceps  (E.). — Valves  linear,  curved, 
with  dilated,  slightly  revolute,  broadly 
rounded  ends.  EA.  p.  125,  k  M.  pi.  5. 2^ 
f.  36.  Europe  and  America.  Some  at 
least  of  Ehrenberg's  figures  in  the  '  Mi- 
crogeologie'  belong  to  Synedra  jiexuosa. 

E.  Alpina  (K.)  =  HimanticUum  Hal- 
cy o)ieIl(B  (Vevty). — Valves  with  turgid 
convex  dorsum,  slightly  produced  sub- 
truncate  apices,  and  verv  fine  transverse 
strife.  KB.  p.  36,  t.  3.  £  10.  S^^dtzer- 
land. 

E.  incisa  (Greg.).  —  Valves  arcuate, 
slender,  with  obtuse  or  subacute  apices, 
and  subterminal  notches  or  depressions 
on  the  ventral  margin ;  strife  fine,  44  in 
•001".  Greg  MJ.  vol.  ii.  p.  96,  pi.  4. 
f.  4.     Lapland,  Scotland. 

E.  Plectrum,  EM.  pi.  6.  2.  f.  15. 
Fossil.  Sweden.  Valve  semilunate,  con- 
stricted beneath  the  capitate  apices ; 
venter  straight ;  dorsum  evenly  convex. 

E.  Hemicyclus  (E.).  —  Small ;  valves 
linear,  curved,  semicircular,  with  obtuse 
apices  and  distinct  ti-ansverse  striae.  = 
Synedra  Hemicyclus,  ERBA.  1840,  & 
M.  t.  16.  =  E.  Falx,  Greg  MT.  vol.  ii. 
p.  105 ;  MJ.  vol.  iii.  pi.  4.  f.  1.  Fossil. 
Sweden. 

2  *  Valves  with  two  dorsal  and  three 
ventral  undulations. 

E.  Crocodilus  (E.). — Valves  elongated, 
slightly  cm'ved,  with  two  dorsal  and 
three  ventral  undulations;  apices  pro- 
duced, subacute,  reflexed.  ERBA.  1845, 
p.  77  ;  M.  pi.  34.  5  a.  f.  4.  Africa  and 
America. 

E.  Tapacumae,  EM.  pi.  34.  5  a.  f.  5. 
America.  Valve  with  two  dorsal  and 
three  ventral  undulations  separated  by 
deep  sinuses;  apices  abruptly  produced 
into  a  short  beak.  E.  Tapacumae  seems 
to  differ  from  E.  Crocodilus  in  its  stouter 
form,  deeper  sinuses,  and  more  abruptly 
produced  apices. 

3  *  Valves  with  detitate  or  crenate 
dorsum. 

E.  Camelus  (E.).  —  Valves  striated, 
small;  dorsmn  with  two  approximate 
rounded  elevations,  sloping  to  the  atte- 
nuated, produced,  obtuse   apices.     EA. 


p.  125,  t.  2. 1.  f.  1.     Asia,  Africa,   and 
America. 

E.  hidentula  (S.). — Valves  faintly  stri- 
ated, with  two  prominent,  acute  or 
rounded  dorsal  ridges,  very  straight 
ventral  margin,  and  obtuse,  produced 
apices.  SBD.  vol.  ii.  p.  83.  E.  Camelus, 
Grev  ANH.  2nd  series,  vol.  xv.  pi.  9.  f.  1. 
Britain.  Differs  from  E.  Carnelus  in  its 
straight  ventral  margin. 

E.  Sella  (E.). — Valve  dilated ;  ventral 
margin  straight;  dorsum  with  two  central 
ridges,  from  which  it  passes  with  a  re- 
gular convexity  to  the  acute  apices. 
EA.  p.  126,  t.  2.  1.  f.  7.     America. 

E.  Zygodmi  (E.). — Valves  linear ;  dor- 
sum with  two  approximate  ridges,  from 
which  it  passes  by  a  curvatm-e  to  the 
rounded  apices.  EA.  p.  127,  t.  2.  1.  f.  6. 
America. 

E.  declivis  (E.).  —  Valves  wdth  plane 
venter ;  dorsum  convex,  with  two  ridges 
which  slope  to  the  acute  apices,  EA. 
p.  125,  t.  2.  1.  f.  3.     America. 

E.  impressa,  EM.  pi.  2.  2.  f.  30,  »S:c. 
America.  Small,  striated;  valves  nar- 
row, linear,  with  two  slight  dorsal  im- 
dulations  and  obtuse  ends.  Perhaps  a 
bicrenate  state  of  E.  tridentula. 

E.  hactriana,  EM.  pi.  16.  1.  figs.  29, 
30,  &  pi.  16.  2.  f.  19.  Fossil.  ^  Sweden. 
This  seems  a  distinct  species,  with  linear, 
nearly  straight  valves,  and  two  remote, 
minute  dorsal  teeth. 

E.  f/^Wow  (E.).  —  Valves  stout,  with 
two  rounded  dorsal  ridges  and  broadly 
rounded  ends;  strise  distinct,  radiant. 
E  Inf  p.  192,  t.  21.  f.  23;  SBD.  pi.  2. 
f.  17.  Recent  and  fossil.  Europe,  Asia. 
Africa,  and  America. — This  and  the  thir- 
teen following  species  of  Ehrenberg  we 
regard  as  mere  varieties,  which  differ  only 
in  the  number  of  their  dorsal  elevations. 
The  species  may  be  called  E.  robusta : 
its  valves  are  stout,  semilunate,  wdth 
concave  venter,  broadly  rounded  ends, 
turgid  convex  dorsum  fm*nished  with 
conspicuous,  roimded,  diverging  ridges, 
and  the  strise  are  strongly  marked  and 
highly  radiant ;  as,  however,  the  valves 
increase  in  length,  according  to  the  in- 
creased number  of  dorsal  ridges  each  is 
comparatively  more  slender  than  its  pre- 
decessor, and  the  ridges  are  smaller  and 
resemble  crenations. 

E.  triodon  (E.).  —  Has  three  dorsal 
ridges;  otherwise  resembles  E.  diodon. 
E  Inf.  p.  192;  SBD.  pi.  2.  f.  18.  Recent 
and  fossil.  Em-ope,  Asia,  Africa,  and 
America,  (iv.  4;  ix.  164.) 

E.  tetraodon,  E.,  Sm.,  K.,  Rab. ;  E. 
pcntodon,  E,,  K. ;    E.  Eiadema   (6  ere- 


764 


SYSTEMATIC  HISTOllY  OF  THE  INFUSOEIA. 


nations),  E.,  K.,  Sm.  ;  E.  heptodon, 
E.,  K. ;  E.  ododon,  E.,  K. ;  E.  ennaodon, 
E.,  K. ;  E.  decaodon,  E.,  K. ;  E.  Jien- 
decaodon,  E.,  K. ;  E.  dodecaodon,  E.,  K.  ; 
E.  serrulcda  (13  crenatious),  E,,  K. ;  E. 
jvmiotis  (14  crenations),  E.,  K. ;  E. 
2)oli/odon  (all  forms  with  more  than  20 
crenations),  E.,  K.  Fossil  and  recent. 
Europe  and  America. — Breb.,  Rab.,  and 
Kiitz.  place  E.  tetraodon  in  Himanti- 
diuni  because  the  frustules  are  occa- 
sionally united  into  short  tablets.  We 
are  unable  to  concur  with  them. 

¥^.Eleplias{E.). — Valves  stout,  curved, 
with  three  dorsal  teeth  and  broadly 
rounded  ends.  EA.  p.  126,  t.  1.  4.  f.  5. 
Brazil. 

E.  dizyga  (E.).  —  Valves  striated  (?), 
semilunate ;  dorsum  with  four  teeth,  ap- 
proximate at  the  middle.  EA.  p.  126, 
t.  2.  1.  f.  8.     Cayenne. 

E.  Corona  (Rab.). — ^Valves  nearly  as 
broad  as  long ;  dorsmn  tm-gid,  with  five 
ridges ;  venter  shorter,  and  separated 
from  dorsum  by  a  constriction.  Rab 
Diat.  p.  17,  1. 1.  f.  36.  Italy.  Striae  di- 
stinct, radiant. 

E.  tridentida  (E.).  —  Small ;  valves 
finely  striated,  curved,  narrow-linear, 
wdth  three  slight  dorsal  crenations,  and 
obtuse  recm-ved  apices.  EA.  p.  126, 
t.  2. 1.  f.  14 ;  Grev  Annals,  2nd  series, 
XV.  pi.  9.  f.  2.  Europe,  Asia,  Africa, 
and  America. — We  would  unite  this  with 
the  following  thirteen  species  imder  the 
name  of  E.  Ehrenherf/ii.  The  valves  are 
linear,  curved,  with  small  dorsal  teeth 
or  crenations,  and  become  larger  and 
longer  in  proportion  to  the  number  of 
their  teeth.  The  striae  are  less  radiant 
than  in  E.  robusta,  and  the  dorsum  less 
turgid. 

E.  qucdernana,  EA.  ;  E.  quinaria 
(xii.  39),  EA. ;  E.  senaria,  E.  septena, 
EA.  =  E.  scjitenaria,  EM. ;  E.  octonaria, 
E.  7ionana,  E.  denaria,  E.  undenaria,  E. 
Terra  (12  crenations),  E.  trkkmaria, 
E.  quatuordenaria,  E.  quindenaria,  E. 
hioctonaria.  Recent  and  fossil.  Eu- 
rope, Asia,  Africa,  and  America.  Ehr., 
Kiitz. 

E.  scalaris  (E.,  K.). — Dorsum  with  17 
dorsal  teeth.  EM.  pi.  17. 1.  f.  44.  Fossil. 
Finland.  In  this  and  the  two  following 
species  Ehrenberg  probably  included 
forms  belonging  to  E.  robusta  and  E. 
Ehrenbergii. 

E.  icosodon  (E.,  K.). — Valves  striated, 
linear,  curved,  with  20  dorsal  teeth. 
ERBA.  1845,  p.  77 ;  Microg.  pi.  33.  10. 
f.  3.     Fossil.     America. 

E.  polyodon  (E.)  resembles  E.  icoso- 


don, but  has  more  than  20  dorsal  teeth. 
E.  /.  c.  p.  77 ;  Microg.  pi.  17.  1.  f.  45. 
Fossil.     Finland. 

Doubtful  and  insufficiently  known  Species. 

E.  triglyphis  (E.)  =  E.  triodon,  Ralfs, 
Annals,  vol.  xiii.  pi.  14.  f.  3  ?  Africa  and 
America.     Sussex  ? 

E.  tetraylyphis  (E.).  Asia,  Africa,  and 
America. 

E.  pentaglpphis,  EM.  pi.  16.  2.  f.  22, 
&  pi.  17.  1.  f.  32.  Europe,  Asia,  and 
America.  Valves  minute,  linear,  with 
five  dorsal,  approximate  teeth,  (iv,  3.) 

E.  hexaglyphis,  EM.  pi.  16.  1.  f.  34, 
&  pi.  16.  2.  f.  24.  Europe  and  Asia. 
Resembles  E.  pentaglypliis,  but  has  six 
dorsal  teeth. 

The  above  fomis  are  probably  only 
varieties.  They  seem  to  dift'er  from  E. 
Ehrenbergii  in  more  minute  size,  obso- 
lete or  indistinct  striae,  and  approximate 
teeth. 

E.  Amphidicranon  (E.).  — Valve  qua- 
drangular, straight,  transversely  striated, 
with  constricted  middle  and  emarginate 
ends.  ERBA.  1845,  p.  77  ;  Microg. 
t.  33.  12.  f.  14.^  Fossil.     Oregon. 

E.  brericornis  (E.).  —  Oblong,  dilated 
with  suddenly  acutely  rostrate  ends ; 
venter  slightly  concave  at  the  middle ; 
dorsum  slightlv  convex,  nearlv  smooth 
(very  finely  striated?).  ERBA.  1845, 
p.  363.    Marine.    lndi?t.  =  A.  Nitzschia? 

E.  Cretcs  (E.). — Valves  striated,  nar- 
row-lanceolate, acute,  very  gradually  at- 
tenuated at  each  end.  ERBA.  1844, 
p.  81 ;  EM.  pi.  22.  f.  55,  56.  Cocconema 
Oretce,  E.     Fossil.     Sicily. 

E.  Pileus  (E.). — Small,  striated,  sub- 
quadrate  ;  venter  wider  than  dorsum, 
the  latter  slightly  furrowed ;  ends  ob- 
tuse, rather  prolonged.  EM.  pi.  39.  3. 
f.  42.    Siberia,  Africa,  and  America. 

E.  Gangetica,  EM.  pi.  35  a.  9.  £  2. 
India.  Fragments  large,  striated,  mth 
straight  venter,  convex  dorsum,  and 
broadly  trimcate  apices,  which  are 
slightly  produced  dorsally. 

E.  Australis ;  E.  ceelata ;  E.  Cygmis  ; 
E.  Paradoxa;  E.  sejpcntina,  Australia, 
Ehr.  5  E.Phrygia;  E.lepida;  E.Mosis; 
E.  rostrata ;  E.  Uralensis  ;  E.  apiculata ; 
E.  Siberica ;  E.  borealis ;  E.  Leptostoma ; 
E.  umbilicata,  Asia,  Ehr.  ;  E.  suhulis ; 
E.  curva ;  E.  carinata,  Africa,  Ehr. ;  E. 
Araucaniee;  E.  edulis,  America,  Ehr.; 
E.  Januarii,  Brazil,  Ehr. ;  E.  Guiatiensis ; 
E.Demcrnrcc;  E.Pomeroni;  E.  Savanna; 
E.  synedra,  Guiana,  Ehr. ;  E.  Columbia 
Columbia,  Ehr. 


or  THE  EUNOTIEuE. 


'G5 


Genus  AMPHICIMPA  (E.). — Frustules  in  lateral  view  Innately  curved, 
having  per\ious  transverse  stria)  and  denticulated  margins.  Amphicampa  is 
closely  allied  to  Eunotia  and  Himantidium,  but  differs  in  ha\ing  teeth  on 
both  margins. 

Amphicampa  mirahilis  (E.). — Valves  l  EM.  pi.  33.  7.  f.  2.  =  A.  Emca,  EM. 
linear,  with  rounded  ends ;  dorsum  with    pi.  33.  7.  f.  1.     Mexico,    (iv.  5.) 
six  or  seven  teeth,  and  venter  with  five,  j 

Genus  HIMAjS'TIDIUM  (E.). — Frustules  united  into  filaments  or  tables"; 
lateral  view  arcuate  or  lunate,  transversely  striated.  If  all  the  species  in 
Himantidium  formed  ribbon-like  filaments,  there  would  be  no  difficulty  in 
distinguishing  it  from  Eunotia ;  but  this  is  not  the  case,  and  Kiitzing  has 
well  said,  "  It  must  be  noticed  that  in  many  species  of  Himantidium  the 
individuals  are  not  always  united  into  a  band,  and  therefore  the  generic 
character  is  very  variable  and  stands  on  a  weak  foundation."  Professor 
Smith  observes  that  "  there  is  no  mark  to  distinguish  the  valves  of  the  two 
genera  unless  it  be  in  the  character  of  the  stria?,  which  in  Eunotia  arc 
radiate  and  in  Himantidium  parallel."  If  the  strise  were  indeed  always 
radiate  in  the  one  genus  and  parallel  in  the  other,  a  valuable  diagnostic 
mark  would  be  fui-nished;  but,  unfortunately,  the  convergent  stria?  occur 
only  in  those  species  of  Eunotia  which  have  a  strongly  convex  upper  margin. 
In  the  front  view  Himantidium  resembles  the  Eragilarieae,  but  in  that  family 
the  lateral  view  is  not  arcuate. 


*  Dorsum  simple. 

Himantidium  pectinale  (Dillwyn,  K.). 
—  Frustides  united  in  long  filaments; 
valves  linear,  arcuate,  with  flattened 
dorsum  suddenly  sloping  to  the  obtuse 
apices,  and  slightlv  concave  venter ; 
strise  27  in  -001".  'KB.  t.  16;  SBD. 
p.  12,  pi.  32.  £  280.  =  H.  minus,  KB. 
p.  39,  t.  16.  f  10 ;  H.  strictum,  Rab 
Diat.  t.  1.  f  1  c ;  Fragilaria  pectinalis, 
Lyngb. ;  Fragilaria  grandis,  E  Inf.  in 
part ;  Eunotia  depressa,  EA.  p.  126. 
Europe,    Asia,    Africa,    and    America. 

H.  Soleirolii  (K.). — ^^alves  lunate,  with 
evenly  convex  dorsum,  concave  venter, 
and  rounded  ends;  striae  30  in  -001". 
KIB.  p.  39,  t.  16.  f.  9 ;  SBD.  vol.  ii.  p. 
13,  pi.  33.  £  282.  =  Himantidium  Faba, 
EM.  t.  1.  2.  £  3 ;  Eunotia  Faba,  E.  in 
part  ?  Europe  and  Africa,  (xiv.  13.) 
It  might  have  been  preferable  to  have 
adopted  Ehrenberg's  name  for  this  spe- 
cies, since  it  is  evident  that  the  JI. 
Soleirolii  of  Kiitzing  was  intended  to 
include  all  forms  with  internal  siliceous 
ceUs,  and  his  figures  of  the  valves  belong 
to  another  species. 

H.  parallelum  (E.).  —  Valves  linear, 
stronglv  striated,  curved,  ^\ath  simply 
rounded  ends.  EM.  pi.  14.  £  58.  =  Eu- 
notia parallela,  EA.  p.  126.  Europe, 
Asia,  Afi-ica,  and  America. 

H.  monodon  (E.).  —  Frustules   large, 


few  together ;  valves  arcuate,  with  some- 
what gibbous  dorsmn,  and  obtuse,  shghtly 
produced  apices ;  strioe  34  in  -001".  EA. 
p.  129,  t.  4.  =  Eunotia  monodon,  EM, 
many  figm-es.  SBD.  vol.  i.  pi.  2.  £  16. 
Common.  Europe,  Asia,  Australia,  Africa, 
and  America,    (xv.  16,  17.) 

H.  prceruptum  (E.). — Valves  striated, 
elongated ;  dorsimi  very  convex,  with  a 
notch-like  depression  near  the  dilated 
truncated  apices.  =  Eunotia  preerupta^ 
EA.  p.  126,  &  M,  several  figures.  Asia, 
Australia,  and  America.  According 
to  Ehrenberg's  figures,  its  valves  scarcely 
differ  from  those  of  H.  monodon, 
except  by  their  more  truncate  apices, 
and  can  scarcely  be  placed  in  another 
genus. 

H.  Arcus(Fi.). — Valves  linear,  arcuate; 
dorsum  sinuated  towards  the  rounded 
dilated  apices.  ERBA.  1840,  p.  17,  & 
M,  many  ^gm:es.=Eu7iotia  Arcus,  EM. 
Europe,  Asia,  Australia,  Africa,  and 
America.  /3,  extremities  gradually  taper- 
ing, =  H.  attenuatum,  Bab  Diat.  p.  19, 
t.  1.  £  10.     Germany. 

H.  gracile  (E.). — Valves  slender,  nar- 
row-linear, slightly  arcuate,  with  obtuse, 
somewhat  recm-ved  extremities.  EA. 
p.  129,  t.  2 ;  SBD.  vol.  ii.  p.  14,  pi.  33. 
£  285.  =  Eunotia  uncinata,  EA.  p.  126, 
&  M.  pi.  15  B.  £  23.  Europe,  Asia, 
Australia,  Africa,  and  America.  Habit 
of  H.  Arc/us,  but  more  slender,  E.  Striae 
27  in  -OO'l".  S. 


766 


SYSTEMATIC  HISTOET  OF  THE  INFUSORIA. 


11.  tnojus  (S.). — Valves  linear,  arcuate, 
witli  rounded,  subcapitate  extremities : 
stripe  27  in  -001".  SBD.  vol.  ii.  p.  14, 
pi.  33.  f.  286.  Britain.  Dillers  little 
from  H.  gracile,  save  in  its  greater  size 
and  elevated  dorsum,  and  is  probably  a 
sporangial  form  of  it  or  some  other 
species,  S.  It  scarcely  differs  from  some 
of  Ehrenberg's  figures  of  H.  paralleltan, 
except  in  its  more  inflated  ends. 

H.  exiguiwi  (Breb.).  — Valves  slender, 
narrow-linear,  arcuate,  with  obtuse  re- 
cm'ved  extremities,  and  42  very  delicate 
striae  in  -001".  KSA.  p.  8.  Eunotia 
(jraciUs,  SBD.  vol.  i.  p.  16,  pi.  30.  f.  249. 
Europe. 

H.  Veneris  (K.).  —  Valves  smooth, 
plano-convex,  vdth  acute  apices.  KB. 
p.  39,  t.  30.  f.  7.  Eunotia  IcBvis,  EM. 
pi.  39.  3.  f.  41.     Trinidad. 

2  *  Valves  with  crenate  or  toothed 
dorsum. 

H.  bidens  (E.). — Valves  with  plane  or 
slightly  concave  venter,  biundulated 
dorsum,  and  dilated,  truncate  apices. 
EA.  p.  9,  &  M,  several  figm-es.  =  Eu- 
notia bidens,  EA.  p.  125,  &  M.  pi.  2.  1. 
f.  2  ;  Eunotia  bigibba,  KSA.  p.  6  ?  Eu- 
rope, Asia,  and  America.  The  dorsum 
has  a  notch-like  depression  near  each 
end. 

H.  Guiancnse  (E.). — Valves  dilated  at 
the  middle,  with  two  dorsal  undulations, 
and  tapering,  slightlv  reflexed  ends. 
EA.  p.  129,  t.  2.  l.'f.  4.  Cayenne, 
(xii.  54.) 

H.  Papilio  (E.). — Valves  subquadrate, 
with  a  much  dilated  bicrenate  dorsum, 
constricted  near  the  obtuse  apices.  EA. 
p.  129,  t.  2.  1.  f.  2.  Asia  and  America, 
(xn.  45,  49-62.) 

H.  undulatum  (S.).  —  Valves  linear, 
with  gibbous  venter,  three  or  more 
slight  dorsal  midulations,  and  obtuse, 
somewhat  recurved  apices.  SBD.  vol. 
ii.  p.  12,  pi.  33.  f.  281.  Europe.  Distin- 
guished fi'om  the  other  British  species 
by  its  gibbous  venter. 

H.  denticulatum  (Breb.). — Valves  very 
naiTow,  arcuate,  with  denticulated  dor- 
sum and  slightly  recurved  apices. 
KSA.   p.    10.     France.     Dorsum   mar- 


gined with  minute  teeth,  constricted 
near  the  rounded  apices. 

H.  triodon  (Perty).  — Valves  smooth, 
■udth  concave  venter,  convex  triundu- 
lated  dorsum,  and  broadl}^  rounded  ends. 
Perty,  Inf  p.  198,  t.  17.  f.  5.  Switzer- 
land. Very  like  Eunotia  diodon  j  but 
striie  have  never  been  observed.  Frus- 
tules  mostly  clear  as  crvstal.    Pertv. 

H.  ternarium,  EM.  pi.  34.  6  a.'  f.  5. 
Florida.  Valves  arcuate,  with  slightly 
concave  venter,  three  dorsal  undulations, 
and  obtuse  apices. 

H.  quaternarium  (E.). — Valves  nar- 
row, very  finely  striated ;  dorsum  a  little 
convex,  deeply  fom'-toothed  ;  venter 
slightly  concave,  with  attenuated  and 
recurved  apices.  ERBA.  1852,  p.  235. 
California.  Joints  of  the  chain  4  to  7, 
three  times  as  broad  as  long,  E. 

H.  quinarium  (E.). — Valves  as  in  H. 
quaternarium,  but  with  five  dorsal  teeth. 
E.  /.  c.  p.  535.  California,  Asia,  and 
Africa.  Joints  of  the  chain  14,  five  times 
as  broad  as  long.  The  frustules  of  H. 
quaternarium  and  II.  quinarium  are  very 
similar  to  those  of  Eunotia  quaternaria 
and  E.  quinaria,  but  are  distinguished 
by  forming  chains  and  by  the  attenuated 
ends  of  the  valves,  E. 

Douhtfid  Species. 

H.  carinatum,  EM.  pi.  34.  6  a.  f.  6. 
Florida.  Frustiiles  rectangular,  smooth, 
with  a  transverse  median  band. 

H.  ?  marinum  (S.).  —  Filaments  tena- 
cious ;  valves  costate,  slightly  and  regu- 
larlv  arcuate,  mth  acute  apices  ;  costse 
10  in  -001".  S  Aimals,  Jan.  1857,  p.  10, 
pi.  2.  f.  14.  Marine.  France.  Distin- 
guished by  its  marine  habitat  and  costate 
valves. 

Species    known    to    us    only    by    name : 
probably   several   of  them   are   merely 
concatenated    states    of  Eunotia    and 
Epithemia. 
H.  AustralicE,  E.,  Australia ;    H.  Ca- 

melus,  E.,  Asia ;  H.  Textrictda,  E.,  Asia ; 

K.Zebra,^.,  Asia;  H.  venirale,  E.,Asia; 

H.  amphioxys,  E.,  Asia ;  H.  umbilicatum, 

E.,  Asia  ;  H.  JEthiopicuin,  E.,  Asia  j  H. 

Falklandii,  E.;  Falkland  Islands. 


FAMILY  II.— MERIDIEM. 

Frustules  prismatic,  attenuated  at  the  base,  attached,  at  least  when  young, 
to  a  gelatinous  cushion;  in  front  view  cuneate,  in  lateral  view  clavate  or 
obovate,  with  pervious  transverse  costae  or  striae.    Ktitzing  places  the  MeridieaB 


between  the  Eunotieae  and  Fragilariece 


and  Meneghini  would  unite  them 


OF  THE  MERIDIEM.  767 

with  the  latter,  for  he  ''  does  not  consider  the  cuneate  form  of  the  frustnles 
of  any  valne  in  an  organological  point  of  view,"  because  of  the  occasional 
occiuTences  of  such  fmstnles  in  Diatoma  and  other  genera  of  the  Fragilarieae. 
In  the  latter  family,  however,  the  cuneate  frustulcs,  when  present,  are  in 
general  interposed  between  those  of  the  normal  shape,  and  the  lateral  surfaces 
have  not  dissimilar  extremities.  Kiitzing  observes  that  "  the  forms  of  this 
family  have  very  great  similarity  to  those  of  Gomphonema,  with  which  they 
may  be  the  more  easily  confounded  when  the  indi\iduals  occur  singly ;  but 
they  are  essentially  distinguished  from  that  genus  by  not  having  a  central 
nodule  in  the  secondary  sides,  and  by  their  uninterrupted  transverse  striae. 
Moreover,  this  family  is  much  more  closely  united  to  the  genus  Odontidium, 
from  which  it  is  distinguished  solely  by  the  form  of  the  secondary  sides, 
which  are  not  symmetrical  at  both  ends."  AVe,  however,  consider  its  affinity 
with  the  Licmophoreae  still  more  evident.  The  Meridiea?,  Licmophoreae,  and 
Gomphonemese  "  form  a  group  [the  Styllarieae  of  Agardh]  distinguished  by 
the  triangular  form  of  the  frustules,  which  have  their  smaller  ends  directed 
towards  a  common  centre.  The  frustules  in  this  group  have  a  central  and 
two  lateral  portions,  as  in  Diatoma  and  Fragilaria,  in  which  genera  cuneate 
frustules  are  also  occasionally  met  with.  But  in  the  Fragilarieae,  when  two 
or  more  cuneate  frustules  are  united,  the  alternate  frustules  have  their 
smaller  ends  in  opposite  directions,  and  hence  their  filaments  are  linear; 
whilst  they  are  attached,  if  at  all,  only  by  the  basal  frustule.  In  this  group, 
on  the  contrary,  as  the  smaller  ends  are  in  the  same  direction,  they  point  to 
a  common  centre,  and  when  stipitate,  each  frustule  is  attached  to  the  stipes  " 
(Ealfs).  The  frustules  in  the  Meridieae  have  two  pun  eta  at  the  broader  end, 
and  sometimes  other  two,  but  more  obscui'e,  at  the  smaller  end  ;  they  want, 
however,  the  sutural  or  fracture -like  longitudinal  lines  which  are  present  in 
the  Licmophoreae. 

Genus  MERIDION  (Leibl.,  Ag.). — Frustules  cuneate,  imited  in  a  spiral 
filament ;  transverse  costae  of  lateral  siu"faces  pervious.  "  The  species  vary 
according  to  the  circumstances  of  development,  as  well  with  respect  to  size 
as  to  other  relations.  The  individuals  are  met  with  both  singly  among  other 
Algae  and  also  in  masses.  At  times  examples  are  found  which  are  always 
composed  of  only  few  individuals ;  others  again  consist  of  individuals  united 
in  greater  number ;  but  generally  the  longer  spiral  ribands  are  rare."  (Kiitz.) 
Professor  Kiitzing  formed  a  new  genus  (Eumeridion)  for  the  reception  of 
M.  constrictum ;  but  his  reasons  have  been  considered  inadmissible  by  De 
Brebisson,  Meneghini,  and  Smith.  Meridion  is  remarkable  for  the  frequent 
occurrence  within  its  frustules  of  an  obovate  silicious  ceU,  which  is  usually, 
but  not  invariably,  divided  into  two  symmetrical  portions  by  a  longitudinal 
suture ;  the  lateral  margins  of  the  inner  cell,  as  well  as  the  sutiu'al  line,  are 
crenulate  like  those  of  the  original  frustule.  The  different  aspect  presented 
by  specimens  in  this  condition  has  induced  some  observers  to  describe  them 
as  a  distinct  species.  A\TiLlst  we  agree  with  Professor  Smith  that  the  modi- 
fication is  insufficient  to  warrant  such  a  separation,  we  cannot  coincide  with 
him  in  regarding  it  even  as  a  variety,  since  frustules  with  these  internal  ceUs 
are  indiscriminately  mixed  mth  ordinaiy  frustules  in  the  same  filament.  So 
common,  indeed,  is  this  occuiTence,  prior  to  the  termination  of  individual  hfe, 
that  we  have  long  been  convinced  that  it  is  the  normal  mode  of  termination 
in  this  genus. 

=  31.  vernale,  E. ;  M.  Zinckeiii  {vnth.  in- 


Meridion  circulare  (Grev.,  Ag.).  — 
Frustules  iu  lateral  view  clavate  or 
obovate.  SBD.  vol.  ii.  p.  6,  pi.  33.  f.  277. 


temal   cells),    KB. ;     B.    curvatum,   K. 
Frustides    slightly  arcuate.      Common, 


'68 


STSTEITATIC  HISTORY  OF  THE  INFUSORIA. 


fonning  a  mucous  browii  stratum  on 
leaves,  stones,  &c.,  in  sliallow  waters. 
/3,  France,  (ix.  177,  178-  xiii.  21,  M. 
Zinckeni.)  In  both  the  primary  and  in- 
ternal cells  the  lateral  margins  have  a 
beaded  appearance,  produced  by  the 
ends  of  the  lateral  costae. 

]M.  comtrictum  ( Ralfs). — Lateral  valves 
constricted  beneath  the  apex,  other^dse 
as  in  31.  circulare,  SBD.  vol.  ii.  pi.  32. 
f.  278.  =  Eiimeridion  constriction,  KSA. 
p.  11.  Common.  Europe.  Internal  cells 
as  in  31.  circulare.  We  have  received 
very  perfect  specimens  from  Mr.  Okeden, 
gathered  in  Wales. 

Doiihtfid  Species. 
M.  ?    panduriforme    (E.).  —  Lateral 
valves   constricted  near  the  ends,   the 


capitate  extremity  acuminated.  E  Infus. 
pi.  16.  f.  3.  1-430".  Form  that  of  Gom- 
phonema  acumincdum. 

M.  ?  ovutmn  (Ag.).  — Frustules  ovate, 
combined  into  a  celUdose  lamina.  KSA. 
p.  10.     Sweden. 

M.  ?  coccocanipyla,  EM.  pi.  14.  f.  79. 
Berlin.  Perhaps  a  bad  tigure  of  one  of 
the  preceding  species  with  internal 
cells. 

M.  marimim  (Greg.).  —  Front  view 
sublinear,  with  coarse  marginal  puncta ; 
valves  clavate,  with  16  coarse  marginal 
strife  in  -001",  and  a  blank  longitudinal 
median  line.  Greg  D  Clyde,  p.  25,  pi.  2. 
f.  41.  Marine.  Scotland.  Frustules 
two  to  four  together.  Certainly  not  a 
true  species  of  this  genus,  as  its  costte 
are  not  pervious. 


Genus  ONCOSPHENIA  (E.). — Frustules  quadrangular,  cuneate,  not  con- 
catenate ;  valves  without  an  umbilicus,  and  also  destitute  of  lateral  apertui^es ; 
and  internal  septa  equal,  but  their  apices  unequal  on  account  of  their  cuneate 
and  uncinate  form.  Oncospheniae  apj^roach  nearest  to  Podospheniae  by  the 
absence  of  pedicels  in  the  latter,  but  are  peculiar  in  theii'  uncinate  form. 
We  are  unacquainted  with  this  genus,  and  ignorant  of  the  reasons  which 
induced  Professor  Kiitzing  to  place  it  among  the  Meridieae. 

nules   11.     Probably  a  distorted   state 


Oncosphenia  Carpathica  (E.). — La- 
teral valves  cuneate,  laxly  striated ;  one 
end  turgid,  rounded,  straight,  the  other 
attenuated  and  uncinate.  KSA.  p.  11. 
Cai*pathian    Mountains.     1-792" :    pin- 


of  some  other  species  similar  to  the 
variety  of  Diatoma  elonycdum  figured  by 
Professor  Smith  in  BD.  pi.  60.  f.  311. 


FAMILY  III.— LICMOPHORE^. 

Frustules  cuneate,  longitudinally  bivittate,  attached  or  stipitate,  solitary 
or  united  in  a  fan-like  manner ;  lateral  surfaces  striated  or  smooth,  but  not 
costate.  The  fmstules  in  the  front  view  are  cuneate,  and  have,  like  the 
generality  of  the  Diatomaceae,  two  puncta  at  each  end,  the  upper  ones,  how- 
ever, being  most  conspicuous.  Most  frequently  two  longitudinal  sutiu^e-like 
lines,  corresponding  to  the  puncta,  are  more  strongly  marked  in  the  Licmo- 
phoreae  than  in  most  other  families ;  these  Kutzing  caUs  "  vittae,"  and  has 
formed  a  tribe  which  from  them  he  calls  '^  Diatomeae  vittatae."  The  vittae, 
however,  are  not  peculiar  to  this  tribe  ;  for,  as  Meneghini  justly  remarks, 
*^  they  are  merely  the  same  longitudinal  lines  which  run  along  the  primary 
surfaces  of  almost  all  the  Diatomaceae"  (MeD.  p.  462).  Professor  Smith 
describes  them  as  ''  modifications  in  the  outline  of  the  valve,  which  in  Podo- 
sphenia  is  slightly  inflected  at  its  larger  extremity,  causing,  on  a  front  view, 
the  appearance  of  notches  at  the  spot  where  the  valves  unite  with  the  con- 
necting membrane  (central  portion)  and  the  foramina  exist.  The  apparent 
prolongation  of  this  notch  to  the  lower  extremity  of  the  frustule  is  nothing 
more  than  the  valvular  suture  which  is  seen  in  all  the  Diatomaceaj "  (SBD. 
vol.  i.  p.  82). 

The  cuneate  shape  of  the  frustules  in  the  front  view,  and  the  dissimilar 
ends  of  the  lateral  surfaces,  distinguish  the  Licmophorcae  from  Synedra,  the 
species  of  which  often  resemble  them  in  habit. 


OF  THE  LIOMOPHORE.E. 


769 


Genus  PODOSPHEXIA(E.).—Fmstiiles  affixed,  in  front  view  cuneate, 
in  lateral  view  elavate,  stipes  none  or  obsolete.  Podosphenia  is  identical  with 
Styllaria  (Ag.).  Its  sessile  frustules  distinguish  it  from  the  rest  of  tho 
Licmophorece,  and  the  absence  of  transverse  costa3  from  the  Meridieae.  "  This 
genus  represents  in  the  Licmophorea)  the  genus  Sphenella  of  the  Gompho- 
nemete ;  for,  like  that,  it  is  distinguished  from  other  genera  of  the  same  family 
by  the  more  or  less  complete  absence  of  the  stipes.  The  obovate-lanceolate 
figure  of  the  secondary  surfaces  is  precisely  that  of  the  Sphenellae  and  of  the 
Gomphonemeae  in  general.  The  cuneate  form  of  the  primary  surfaces  is,  in 
Podosphenia,  always  more  dilated  at  the  summit  and  acute  at  the  base,  so 
that  they  resemble  a  triangle  more  than  a  trapezium."    (M  I.  c.  p.  462.) 

nia   ahhreviata,   E. ;   P.  Linghyei,  SBD. 


PoDOSPHENiA^i7/-«a7/,s(E.). — Frustides 
narrow  cuneate,  elongated,  with  some- 
what acute  base;  lateral  \dew  elavate, 
smooth  or  with  verv  obscure  striae.  KB. 
t.  9.  f  10.  1.  Europe,  (x.  186.)  jS.  mino)' 
1-250"  to  1-110". 

P.  tenuis  (K.). — Linear  cuneate,  elon- 
gated, very  slender,  with  acute  base ; 
lateral  view  narrow-clavate.  KB.  t.  -30. 
f.  51.     Norway. 

P.  7iana  (E.). — Small,  smooth,  narrow 
linear  cuneate ;  lateral  view  elavate  with- 
out lines.  EM.  pL  11.  f.  18,  19.  Fossil. 
Bilin,  Bohemia^     1-2300"  to  1-1720". 

P.  clehiUs  (K.).  —  Smooth,  narrowly 
cuneate,  rather  acute  at  the  base,  sub- 
flabellate.  KB.  t,  8.  f.  7.  Em-ope. 
1-1380". 

P.  tergesiina  (K.).  —  Cuneate  trian- 
gular, geminate  or  ternate,  conjoined  in 
a  ilabeUate  manner,  base  rather  acute. 
KB.  t.  8.  f.  13.    Trieste.    1-1440". 

V.hyalina  (K.), — Very  hyaline,  cu- 
neate, with  approximate  \dttiie  and  sub- 
acute base ;  lateral  view  obovate  pvri- 
form.  KB.  t.  10.  f.  2.  /S.  r«ce/;ws«,'K., 
obsoletely  stipitate,  1. 10.  f.  3.  Em'ope. 
1-570"  to  1-480". 

P.  cuneata  (Lyngb.,  Ag.).  —  Broadly 
cuneate  with  rather  acute  base;  lateral 
view  elavate  or  obovate,  with  obscure 
striae.  =  Styllaria  cuneata,  Ag. ;  Podosphe- 

Genus  HHIPIDOPHOPA  (K.). — Frustules  stipitate,  in  front  view  cuneate, 
in  lateral  view  obovato -lanceolate  ("^ith  a  median  longitudinal  line,"  S.). 
"  We  encounter  the  same  difficulty  in  distinguishing  Ehipidophora  from 
Podosphenia  that  is  experienced  when  practically  applying  the  generic 
distinction  established  between  Sphenella  and  Gomphonema  and  in  aU  other 
similar  cases  (Cymbella  and  Cocconema,  &c.) ;  these  diifer  only  in  the  stipes, 
which  is  very  variable  in  length  and  not  always  entirely  wanting  in  the  first 
of  these  two  genera. 

"  The  large  size  of  some  among  the  species  enumerated  by  Kiitzing  permits 
us  to  observe  clearly  the  conformation  of  the  shield.  Let  us  suppose  a 
cylindrical  articulation  of  Melosii'a,  and  so  compress  it  unequally  on  one  of 
its  sides,  and  in  the  direction  of  both  pairs  of  opposite  surfaces,  that  the 
resulting  form  shall  be  cuneate,  and  the  two  incomplete  diaphragms  formed 
by  the  internal  prominence  of  the  longitudinal  canals  shall  extend  like  these 

3d 


Europe,  (xm.  13  h.)  1-240".  Stride  46 
in  -001",  S.  Broader  and  shorter  than 
P.  gracilis. 

P.  Jurgensii  (Ag.,  K.). — Broadly  cu- 
neate with  trmicate  base ;  lateral  view 
elavate,  vnih.  obscure  striae.  SBD.  i. 
p.  83,  pi.  25.  I  228.  Europe.  1-432". 
Strii©  48  in  -001",  S. 

P.  ovata  (S.). — Cuneate  with  rounded 
angles ;  lateral  view  obovate,  tapering 
into  an  acute  base ;  striae  moniliform. 
SBD.  i.  p.  83,  pi.  24.  f.  226.  Shoreham 
harbour.  Stride  24  in  -001".  -0033"  to 
•0042",  S. 

P.  Ehrenhergii  (K.).  —  Large,  broadly 
cuneate;  lateral  view  tapering  at  both 
ends  and  with  distinct  moniliform  trans- 
verse striae.  SBD.  pi.  24  £  225.  Eu- 
rope, (iv.  7 ;  XIII.  14.)  1-140".  Striae 
27  in  -001",  S. 

Doubtful  Species. 
P.  Pupula,  EM.  Several  figures.  Ehr- 
enberg's  figm-es  have  a  elavate  lateral 
valve  with  pervious  transverse  costae  and 
wdth  or  without  a  constriction.  All  pro- 
bably belong  to  3Ieridion  circulare  and 
M.  constrictum.  He  gives  about  twenty 
stations  for  this  species  m  different  parts 
of  the  globe, — none  marine. 


'70 


SYSTEMATIC  HISTOKT  OF  THE  LNFUSOillA. 


and  lose  themselves  towards  the  pointed  extremity  which  forms  the  base ; 
such  is  the  structure  of  Podosphenia  and  Ehipidophora.  Viewed  on  one 
side,  that  is,  on  the  lateral  surfaces,  they  present  an  obovate  arch,  marked 
on  the  periphery  of  the  surfaces  themselves.  The  margin  of  this  arch  is 
tliickened  by  the  presence  of  the  canal,  which,  seen  in  front,  presents  in  the 
cm*ve  its  brightness  with  an  appearance  of  perforation."  (Meneg  I.e.  p.  463.) 
Professor  Smith  says  that  "  a  close  examination  of  the  frustules  shows  us 
that  the  distinct  and  even  moniliform  striae  so  conspicuous  in  Podosphenia 
are  almost  wholly  wanting  in  our  native  species  of  Ehipidophora."  The 
stria3  in  the  former  genus,  however,  are  not  always  detected  with  facility, 
since  Meneghini  remarks  that  "  of  the  nine  species  described  and  figured  by 
Kiitzing,  only  one  (P.  Ehrenhergii)  presents  transverse  striae  on  the  secondary 
sm^faces."  Careful  observation  of  the  species  of  Ehipidophora  in  a  gromng 
state  will  probably  prove  that  several  of  them  have  been  constituted  upon 
insufficient  grounds.  It  is  to  be  feared,  indeed,  that  characters  taken  from 
the  comparative  length  and  stoutness  of  the  stipes,  its  simple  and  branched 
condition,  and  even  the  shorter  or  longer  form  of  the  wedge-shaped  frustules 
in  the  front  view,  are  more  or  less  fallacious.  We  believe  that  at  least  some 
of  the  species  are  at  first  furnished  with  a  short,  thick,  simple  stipes,  beaiing 
the  associated  frustules  at  its  apex,  and  that  by  the  process  of  growth  the 
frustules  become  longer  in  proportion  to  their  breadth,  and  lose  theii^  flabel- 
late  arrangement  by  the  subsequent  elongation  and  dichotomous  division  of 
the  stipes. 


Ehipidophora  cj^ystalUna  (K.).  — 
Shortly  stalked,  flabellate  ;  frustules 
shortly  cuneate,  rather  broad,  obtuse  at 
the  base.  KB.  t.  9.  I  10.  5.  German 
Sea.     1-1200"  to  1-1300" 

E.  (Edipusilv.). — Very  shortly  stalked, 
siibflabellate ;  frustules  oblong  cuneate, 
truncate  at  the  base ;  stipes  hemisphe- 
rical. KB.  t.  18.  i.  5.  5,  7.  Europe. 
1-600"  to  1-480". 

E.  Anglica  (K.).  —  Shortly  stalked, 
flabellate  ;  frustules  turgid,  cuneate  with 
truncate  base  and  obtuse  terminal  angles; 
stipes  rather  long,  simple,  thick.  KB. 
t.  27.  f.  5.  2,4.     Europe.     1-600". 

E.  Ansfralis  (K).  —  Flabellate;  frus- 
tules narrowly  cuneate  with  truncate 
base ;  stipes  simple,  thick.  KB.  t.  9. 
f.  5.     Trieste.     1-540". 

E.  horealis  (K.).  —  Flabellate  ;  frus- 
tules large,  oblong  cuneate  with  slightly 
obtuse  base  ;  stipes  simple,  rather  stout. 
KB.  t.  9.  f  6.     Heligoland.     1-310". 

E.  Nubecula  (K). — Frustules  hyaline, 
broadly  cuneate,  somewhat  acute  at  the 
base,  scattered,  subsolitary  or  fasciculate, 
lateral  and  terminal ;  stipes  filiform, 
elongated,  subramose.  KB.  t.  8.  f  16. 
Europe,    (xiii.  17.)     1-720"  to  1-600". 

E.  teneJla  (K.).  —  Minute  ;  fi-ustules 
small,  broadly  cuneate,  conjoined  in  an 
imperfectly  flabellate  manner,  acute  at 
the  base  ;  stipes  slender,  very  finely 
branched.  KB.  t.  11.  f.  3.  Europe. 
(XIII.  15.)     1-1080"  to  1-960". 


E.  Dalmatica  (K.).  —  Flabellate  in  a 
radiatiug  manner;  frustules  oblong  cu- 
neate ;  stipes  short,  rather  stout,  at  leiigth 
subramose,  tubular.  KB.  t.  9.  f.  7. 
Europe.  1-540".  Lateral  view  narrow- 
clavate  with  very  obscure  strise. 

E.  ahhreviata  (Ag.,  K.).  —  Subflabel- 
late ;  frustules  broadly  cuneate  with  acute 
base  ;  stipes  rather  thick,  at  length 
branched.  KB.  t.  9.  f.  14  =  Licmophora 
ahhreviata,  Ag.  Europe.  1-540".  "  Ee- 
sembles  R.  paradoxa,  but  is  distinguished 
by  its  green  colour  when  dried."   (Ag.) 

E.  paradoxa  (Lyngb.,  K.). — Frustules 
short ;  broadly  cuneate,  somewhat  acute 
at  the  base ;  stipes  slender,  filiform,  di- 
chotomous ;  lateral  \aew  clavate.  SBD. 
i.  p.  84,  pi.  25.  f.  231  =  Gomplionema 
paradoxnm,  Ag.  1-540"  to  1-480".  Co- 
lom'ing  matter  dull  olive.  The  frustide, 
especially  in  dried  specimens,  often  has 
its  angles  so  much  rounded  as  to  become 
obovate,  —  a  character,  however,  not 
peculiar  to  this  species,    (iv.  8.) 

E.  tincta  (Ag.). — Frustules  elongated, 
narrow  cuneate,  mth  somewhat  acute 
base ;  stipes  elongated,  subdichotomous, 
slender.  =  Gom.  tinctum,  A  Consp  D. 
p.  35  ;  R.  ehmgata,  KB.  t.  10.  I  6. 
1-310".  Colom-ing  matter  dull  olive. 
According  to  Agardh,  it  differs  from  R. 
jmradoxa  in  its  greener  colour  and  longer 
and  more  slender  frustules.  He  also 
states  that  it  resembles  smaller  states 
of  LicmopJwra  Jiahellata,  but  is  shorter 


OF  THE  LICMOPHOKE.E. 


71 


and  more  lax,  and  witliout  radiant  frus- 
tules. 

K.  oceanica  (K.).  —  Friistules  oblong 
cuneate,  dense ;  stipes  elongated,  slender, 
subdichotomous.  KB.  t.  10.  f.  4.  At- 
lantic. iS  flabellate.  1-390".  Internal 
matter  fulvous. 

R.  superha  (K.). — Frustules  geminate 
or  solitary,  oblong  cuneate,  slightly  acute 
at  their  base ;  stipes  long,  filiform,  di- 
ehotomous,  secondary  branches  lateral, 
short.  KB.  t.  10.  I  7.  Europe.  1-310". 
Elegant,  slender,  large ;  internal  matter 
golden-yellow,  globose,  broadly  distri- 
buted. 

R.  gmndis  (K.).  —  Frustules  broadly 
cuneate,  large;  stipes  very  long,  fili- 
form, dichotomous.  KB.  1. 11.  f.  1.  ^. 
orachnoidea  (K.). — Frustules  caducous, 


mostly  lateral.  Venice.  Large,  its  in- 
ternal matter  granular,  globose,  olive. 
1-120". 

E.  Meneghinimia  (K.). — Large;  frus-- 
tules  geminate,  oblong  cuneate,  with 
rather  broad  apices  5  stipes  much  elon- 
gated, filiform,  dichotomous.  KB.  t.  11. 
f.  2.  Venice,  (xm.  19.)  1-288".  In- 
ternal matter  scattered,  globose,  olive- 
brown. 

R.  Craticula  (IVIont.). — Shortly  stalked, 
subflabellate,  dilated  at  the  base,  cra- 
ticuliform ;  frustules  two  to  six,  lanceo- 
late or  oblong-lanceolate,  with  truncate 
apex,  and  obtuse,  scarcely  attenuated 
base.  Montague,  A  d  Sci  Nat.  1850, 
p.  308.  Cayenne.  1-650"  to  1-450". 
Stipes  slender. 


Geniis  LICMOPHORA(A.).  — Frustules  flabeUiform,  stipitate,  in  front 
view  narrow- cuneate,  laterally  clavate ;  stipes  thick,  irregularly  branched. 
Licmoi)hora  is  nearly  identical  with  EchineUa  of  Ehrenberg.  ''  The  finis- 
tules  of  the  present  genus  differ  in  no  essential  respect  from  those  of  Rhipi- 
dophora.  They  are,  it  is  true,  longer  and  narrower,  and  probably  less  firml}^ 
silicious ;  but  none  of  these  circumstances  seem  to  be  of  generic  importance. 
The  separation  of  the  genera  must  therefore  rest  upon  the  fan-like  arrange- 
ment of  the  frustules  upon  the  summit  of  an  incrassate  and  irregularly 
dichotomous  pedicel  which  occui^s  in  Licmophora."    (S  I.  c.  vol.  i.  p.  85.) 

Meneghini,  however,  says  that  "  the  resemblance  of  this  to  the  preceding 
genus  is  only  apparent.     But  a  true  affinity  connects  Licmophora  to  Synedra, 

from  which  it  differs  only  in  its   cuneate  frustules The  vittae  in 

Licmophora  are  not  to  be  compared  with  those  in  Rhipidoj)hora.  They  are 
nothing  more  than  the  usual  longitudinal  canals  projecting  into  the  cavity, 
by  which  the  apparent  perforations  or  sections  of  their  ca\*ities  appear  very 
near  the  margin  of  the  summit.  The  distribution  of  the  internal  coloured 
substance  is  different  from  that  in  the  two  preceding  genera,  and  greatly 
resembles  that  of  Synedi^a."    (M  Z.  c.  p.  464.) 

Licmophora 


splendida  (Grev.).  — 
"Frustules  nearly  linear,  frequently  at- 
tenuate and  roimded  at  the  upper  extre- 
mity; in  lateral  ^dew  attenuate  towards 
the  upper  end."  SB.  i.  p.  85,  pi.  32. 
12S3.  =L.fabelIata,  K. ;  EchineUa  splen- 
dida, E.  Europe.  Differs  from  the  next 
species  by  its  longer  and  nan'ower  frus- 
tules, many  of  which  are  scattered  and 
lateral. 

1^.  Jlahellata  (Grev.,  Ag.). — Frustules 
cuneate,  ti-uncate ;  in  lateral  ^-iew  very 
narrow  clavate.  S.  pi.  32.  f  233.  =X.  ra- 
dians, K. ;  L.  argentescens,  Ag. ;  EchineUa 
flaheUata,  E.  Common.  (iv.  9.  ;  x. 
'191-193.) 

"  I  have  given,  in  accordance  with  the 
authority  of  my  predecessors,  two  species 
of  this  genus ;  but  I  am  far  from  satisfied 
that  they  are  truly  distinct,  and  I  am 


disposed  to  believe  that  a  wider  com- 
parison of  specimens  wUl  necessitate 
their  miion."  (SB.  i.  p. 85.)  Being  unable 
to  determine  the  s^Tionjmis  of  Agardh, 
Ehrenberg,  andKiitzing,  we  have  thought 
it  better  to  foUow  Professor  Smith  than 
to  risk  increasing  the  confusion  which 
exists.  The  Licmophora  argentescens, 
Ag.,  is  remarkable  for  its  silvery  lustre 
when  dried ;  but  we  cannot  detect  any 
valid  diagnostic  difference.  Both  species 
are  remarkable  for  the  X^a^g^  and  beau- 
tiful fan-like  clusters  of  frustules  termi- 
nating their  branches;  other  frustules 
are  lateral  and  scattered. 

L.  Meneghiniana  (K.).  —  Frustules 
sleader,  very  long,  linear  cuneate,  ter- 
minal  ones   radiant,  lateral  ones   scat- 


tered 
KSA. 


stipes 
p.  113. 


elongated,     subdivided. 
Adriatic    Sea.      Leng-th 
3d2 


SYSTEMATIC  HISTOHY  OF  THE  INFrSORTA. 


of  frastiile  1-84"  to  1-72".  The  charac- 
ters given  are  insufficient  to  distinguish 
this  species  from  L.  splendida. 

L.  divisa  (K.).  —  Frustules   elongate 
cuneate,   subsolitary   or    geminate    (not 


flabellate),  acute  at  the  base ;  stipes 
short,  weak,  subdi\aded.  KSA.  p.  114. 
Adriatic  Sea.  (xiii.  16.)  Length  of 
frustule  1-240"  to  1-180". 


Genus  CLIMACOSPHENIA  (Ehr.).  —  Frustules  in  front  view  cuneate, 
■with  moniliform  longitudinal  \itt8e,  laterally  obovate-lanceolate,  divided  into 
chambers  by  transverse  septa.  Marine.  This  genera  resembles  Podosphenia, 
except  in  having  the  peculiar  transverse  septa.  ^'  The  two  (first)  species 
contained  in  this  genus  have  nothing  in  common  except  the  moniliform  vittae. 
But  in  what  these  really  consist  we  cannot  ascertain  from  the  figures.  In 
the  first  Kiitzing  does  not  delineate  the  lateral  surfaces,  and  from  the  figure 
any  one  would  say  that  he  had  drawn  a  Synedra.  The  second,  again, 
resembles  a  Podosphenia."    (Meneg  7.  c.  p.  465.)] 


Clumacosphenia  AustraKs  (K.).  — 
Very  shortlv  stallved,  with  smooth  mar- 
gins. KB.llO.  f.8.  OnAlgaj.  New 
HoUand  and  Southern  Afi-ica. 

C.  momlif/ern  (E,). — Frustules  trans- 
versely striated  on  the  margin;  septa 
10  to  11  in  number.  IvB.  t.  29.  f.  80. 
Cuba,  Mexico,    (xi.  45,  46.) 

C.  elonfjata  (B.). — Lateral  view  elon- 
gated clavate,  the  intercostal  spaces  with 
obsolete  transverse  striae ;  stipes  long, 
branched.  BC.  1853,  p.  8,  pi.  1.  f.  10, 
11.      Florida.      Professor  Bailey   relies 


on  the  "  elongated-clavate  fonn  of  the 
frustiUes  and  their  excessively  minute 
striations,  to  distinguish  this  species 
from  those  previously  described  by  Ehr- 
enberg  and  Kiitzing.  The  strife  can  be 
made  out  without  much  difficidty  near 
the  edges  ;  but  to  trace  them  completely 
across  the  middle  regions  of  the  valve 
requires  excellent  lenses  and  careful 
management  of  the  light."  (Bailey.) 
Frustides  in  fan-shaped  gToups,  narrow, 
linear-cuneate,  with  conspicuous  moni- 
liform longitudinal  vittae. 


Genus  PODOCYSTIS  (K.  &Bail.)=EUPHYLLODIUM  (Sh.).— Frustules 
stipitate,  cuneate  in  front  view  with  obscure  vittae ;  valves  with  transverse 
costae,  moniliform  striae,  and  longitudinal  median  line.  Podocystis  differs 
from  Siuirella  not  only  in  its  stipitate  frustules,  but  in  its  moniliform  striae 
and  absence  of  alae ;  and  from  Bhaphoneis  by  its  cuneate  frustules.  We 
have  placed  it  with  the  Licmophoreae  because  of  its  resemblance  to  Podo- 
sphenia, notwithstanding  its  obscure  vittae  and  strong  transverse  costae. 
Maiine. 


Podocystis  Adriatica  (K.). — ^\^alves 
ovate,  with  11  or  12  sti^ae  in  1-1200", 
stipes  veiT  short.  =  fiurirelJa  (Pudocystis) 
Adriatica,  KB.  p.  62,  t.  7.  f  8 ;  P.  Ame- 
ricana, BMO.  pi.  11.  f.  38 ;  SB.  ii.  p.  101 : 


JEuphyllodiimi  spathidatum,  Shadb.  MT. 
ii.  p.  11,  pi.  4.  f  4 ;  Dorypliora  ?  elegans, 
Roper,  MJ.  ii.  p.  284.  f  3.  Europe,  Afi-ica, 
and  America,     (iy.  10.) 


Genus  SCEPTBONEIS  (E.).— Frustules  simple,  affixed,  cuneate,  com- 
pressed, styliform ;  in  the  lateral  ^dew  with  moniliform  transverse  striae, 
interrupted  by  a  median  longitudinal  suture.  Marine.  Sceptroneis  has  the 
habit  of  a  nonconcatenate  Meridion  and  of  a  Gomphonema  without  the 
central  nodule  of  the  lateral  valves. 


Sceptroneis  Caduceus  (E.). — Frus- 
tides bacillar,  long,  slender,  inflated  at 
centre  and  upper  end,  and  tapering  below. 
BAJ.  xlviii.  pi.  4.  f.  11.  Fossil,  Ame- 
rica;  recent,  Scotland.    The  lateral  view, 

the  only  one  we  have  seen,  is  narrow,  j  in  Scotland,    (iv.  11.) 
somewhat   clavate,  constricted  beneath  i 


the  head,  which  is  rounded  at  its  apex. 
Transverse  striae  with  pear-like  gra- 
nules. Length  1-92",  exceeding  the 
width  about  18  times.  Professor  Gre- 
gory gathered  a  fragment  of  this  species 


OF  THE  FRAGILARIEJi;. 


773 


FAMILY  IA\— FKAGILARIEJE. 

Fiiistiiles  straight,  free,  or  affixed  by  one  augie  of  the  basal  friistiiles,  in 
front  view  linear,  in  lateral  view  compressed,  and  striated  or  smooth,  with  a 
central  nodule ;  stride  or  costce  pervious.  "  The  members  of  tliis  family  are 
allied  in  the  genus  Denticula  to  Surirella  and  IS'avicula ;  in  the  genera  Odon- 
tidium  and  Fragilaria  to  Himantidium,  Diadcsmis,  and  the  Meridie^e,  and  in 
Diatoma  to  Grammatophora  and  Tabellaria."  (Kiitzing.)  ''  The  character  by 
which  these  genera  are  collected  together  into  one  family  is  the  conformity  of 
the  two  primary  surfaces  ;  nor  do  I  know  how  the  genus  Meridion  is  excluded 
even  by  the  minutest  characters."  Kiitzing,  indeed,  "  cites  the  affinities  with 
Himantidium  among  Eunotiese,  with  Diadesmis  among  the  Na\dcul8e,  and 
Avith  the  various  genera  of  Stiiatelleoe.  The  relation  appears  to  us  rather 
one  of  analogy  than  of  affinity,  being  the  polyparifonn  association  of  many 
individuals."  (Meneghini.)  Under  Meridiere  we  state  the  reasons  which 
induce  us  to  dissent  from  Meneghini's  opinion  respecting  the  position  of 
Meridion.  The  striae  and  costae  are  usually  continuous  across  the  valve  ;  and, 
indeed,  Kiitzing  makes  their  jDcrviousness  a  distinctive  character,  separating 
the  Fragilaiiece  from  the  Surirelleae.  We  regard  Meridion  as  far  more  nearly 
allied  to  some  genera  belonging  to  the  latter  family  than  to  the  genera 
mentioned  by  Meneghini. 

Genus  DEo^TICULA  (K.).  —  Free,  sohtary,  or  binately  conjoined,  rarely 
more ;  valves  with  pei^ious  costae,  which  appear  in  front  view  like  marginal 
puncta.  Fresh  water.  Denticula  differs  from  Odontidium  in  not  forming  a 
filament,  and  also,  according  to  Professor  Smith,  in  ha\ing  conspicuous  striae, 
which  are  wanting  or  obscure  in  Odontichum,  and  from  Fragilaria  by  its 
strongly  marked  costae,  which  Kiitzing  regards  as  always  pervious. 

Denticula  tenuis  (K.). — Front  view  I  elliptic,   with   12  to   13   fine    striae 


linear  vvdth  punctated  margin ;  valves 
narrow  lanceolate,  with  10  or  11  trans- 
verse cost^  in  1-1200".  KB.  p.  43,  1. 17. 
£8.     Europe.     1-1080". 

D.  friyicla  (K.).  —  Front  view  linear, 
with  finely  striated  margins ;  valves  li- 
near lanceolate,  vvith  11  or  12  cost£e  in 
1-1200".  KB.  p.  43, 1. 17..  f  7.  Europe. 
Smaller  than  B.  tenuis.     1-1200". 

D.  thermalis  (K.)- — Front  view  oblong 
or  trapezoid,  with  beautifully  punctated 
margins ;  valves  lanceolate,  with  7  or  8 
costaj  in  1-1200".  IG3.  p.  43,  1. 17.  f  6. 
Italy.     1-6G0". 

D.  eJegans  (K.).  —  Front  view  linear 
oblong,  M-ith  obtuse  angles  and  gland- 
Hke  marginal  puncta ;  valves  lanceolate, 
with  6  costfB  m  1-1200".  KB.  p.  43, 
t.  17.  f  5.    Germany,    (ni.  4.)    1-600". 

D.  ohtusa  (K.).  —  Front  view  linear, 
with  striated  margins ;  valves  lanceolate, 
with  obtuse  ends,  and  11  costas  in 
1-1200".  KB.  p.  4:3,  1. 17.  f.  14;  SBD. 
i.  p.  19,  pi.  34.  f  292.    Europe.     1-336". 

D.  crassula  (Niigeli).  —  Front  view 
oblong,  with  punctated  margins  -,  valves 


m 
1-1200".  Nag.  in  KSA.  p.  889.  = 
I),  injlata,  SBD.  ii.  p.  20,  pi.  34.  f.  294. 
Europe. 

D.  acuta  (Rab.).  — Front  \iew  mostly 
cuneate  ;  valves  slender  lanceolate,  with 
6  or  7  costse  in  1-1200".  Rab  Diat. 
p.  33,  1. 1.  £  8.  _  Persia. 

D.  lauta  (Bail.).  —  Front  \iew  linear, 
with  gland-like  marginal  pmicta ;  valves 
linear  lanceolate,  with  obtuse  ends  and 
distant  costae,  which  terminate  in  mar- 
ginal bead-like  dots.  BMO.  ^.  9,  £  1.  2. 
Fossil.     Suisim  Bay,  California. 

D.  ocellata  (S.).  —  Front  view  linear, 
truncate,  with  conspicuous  foramina- 
like  marginal  puncta ;  valves  linear 
elliptic,  with  10  costae  in  -001".  SBD. 
ii.  p.  20.  St.  Abb's  Head.  The  frus- 
tules  in  the  front  view  closely  resemble 
small  specimens  of  Epithemia  Argus. 
The  extremities  of  the  costae  or  canali- 
cidi  appear  as  circidar  foramina  on  the 
f.  v.,  and  the  costae  on  the  side  view" 
also  give  an  ocellated  appearance  to 
the  valve,  S. 


Genus  PLAGIOGRAMMA  (Grev.)  (Heteromphala,  E.).  — Frustulcs  qua- 
drangidar,  united  into  a  short  fascia  ;  valves  with  two  or  more  strong,  pervious 


774 


SYSTEMATIC  HISTORY  OF  THE  INITSORIA. 


transverse  costse,  and  moniliform,  generally  interrupted  striae.  Marine. 
Plagiogramma  is  a  well-marked  genus,  identical,  we  believe,  -svith  Heterom- 
phala  of  Ehrenberg.  We  have  adopted  the  present  name,  not^vithstanding 
the  prior  claim  of  Ehrenberg's,  because  it  is  not  only  better  defined,  but  the 
latter  was  founded  upon  imperfect  knowledge,  when  the  lateral  view,  which 
is  so  important,  had  not  been  observed.  In  the  front  view  the  terminal 
puncta  are  very  conspicuous  and  notch-like,  so  that  the  ends  appear  slightly 
three-lobed,  and  the  termination  of  the  costoe  and  striae  are  conspicuous  along 
the  lateral  margins.  The  valves  are  always  furnished  with  two  central 
transverse  costae,  and  frequently  with  others.  In  addition  to  the  costae  there 
are  moniliform  striae, — the  former  pervious,  the  latter,  except  in  one  species, 
interrupted  by  a  median  line.  We  give  Dr.  Gre\iUe's  arrangement  of  the 
species,  but  must  express  a  doubt  whether  the  number  of  costae  is  not  variable 
in  the  same  species. 

moniliform,  16  in  -001".  Grev  /.  c.  p.  210, 
pi.  10.  f.  10.  Jamaica  and  New  Provi- 
dence.    Side  view  unknown. 

P. pi/ffniceum(Gve\.). — Minute;  valves 
narrow  oblong ;  costae  four ;  striae  moni- 
liform, interrupted,  21  in  -001".  Grev 
/.  c.  p.  211,  pi.  10.  f  11.  Distinguished 
for  its  minute  size,  its  shape,  and  the 
small  number  of  striae,  although  re- 
latively closer.    Grev. 

P.  Grevillii  (Ralfs).  —  Striae  in  front 
view  broad,  moniliform,  costate,  8  or  9 
in -001";  costae  four;  connecting  zone 
Tsdth  longitudinal  rows  of  dots.  =  P.  orna- 
tum,  Grev  I  c.  p.  209,  pi.  10.  f.  9.  CaU- 
fomian  guano.  Side  view  unkno^vTi. 
The  striae  are  very  peculiar,  broad,  at 
first  sight  resembling  costae.    Grev. 

P.  validum  (Grev.). — Valve  linear, 
slightly  dilated  in  the  middle,  roimded 
at  the  ends ;  costae  four ;  striae  inter- 
rupted, conspicuouslv  moniliform,  12  in 
•001".  Grev  I.  c.  p.  209,  pi.  10.  f.  8.  Cah- 
fomian  guano.     Front  view  unknown. 

P.  ohesum  (Grev.).  —  Minute  valves, 
broadly  dilated  at  the  middle  and  romided 
at  the  ends ;  costae  four ;  striae  11  in 
•001".  Grev  I.  c.  p.  211,  pi.  10.  f.  12, 13. 
New  Providence.  The  inflated  appear- 
ance of  the  valves  and  the  small  number 
of  stride  render  this  a  well-marked  spe- 
cies, Grev. 

P.  lymtiim  (Grev.).  —  Valves  con- 
stricted at  the  middle,  then  dilated  and 
narrowly  Ip-iform,  linear,  and  rounded 
at  the  extremities ;  costae  four;  striae  18 


*  Valves  luith  two  centrical  costce. 

Plagioghaimima  Gregoriamim  (Grev.). 
— Front  view  mth  slightly  convex  mar- 
gins ;  valves  lanceolate  oblong,^  obtuse  ; 
costae  two;  striae  pervious,  18  in  -001". 
Grev.  MJ.  ^ii.  p.  208,  pi.  10.  f.  1,  2.  = 
Denticula  staurophora,  Greg  Diat.  of 
Clyde,  p.  24,  pi.  2.  f  37.     Scotland.  _ 

P.  Jamaicense  .(GveY.).  —  Front  view 
with  straight  margins;  striae  continued 
almost  to  the  angles,  16  in  -001" ;  costae 
two.  Grev  /.  c.  p.  208,  pi.  10.  f.  3.  Ja- 
maica. The  striae  can  scarcely  be  termed 
strictly  moniliform,  but  rather  monili- 
form costae.    Grev. 

P.  ?  tesseUatinn  (Grev.).  —  Valves 
broadly  lanceolate,  olituse;  striae  inter- 
rupted, composed  of  large  subquadrate 
granules,  8  in  -001";  costae  tvv-o.  Grev 
I.  c.  p.  208,  1. 10.  f  7.    Californian  guano. 

P.  interruptum  (Greg.). — Front  \iew 
with  slightly  convex  margins ;  costae 
two ;  striae  obsolete  ?  =  Denticula  inter- 
rupta,  Greg  Diat.  of  Clyde,  p.  22,  pi.  2. 
f.  30.     Scotland.     Side  view  unknown. 

2  *   Valves  ivith  two  centrical  costce  and 
one  near  each  end. 

P.  ornatum  (Greg.).— Front  ^dew  with 
convex  margins,  constricted  beneath  the 
dilated  ends ;  costae  four ;  striae  obsolete  ? 
=  Denticula  ornata,  Gres-  Diat.  of  Clyde, 
p.  22,  pi.  2.  f.  32.  Scotland.  Side  view 
unknown. 

V.  pulchelluni  (Grev.). —Valve  linear 
oblong;  costae  four;  striae  robust,  con- 
spicuously moniliform,  interrupted,  11 
in  '001".  Grev  /.  c.  p.  209,  pi.  10.  f.  4-6. 
Californian  guano ;  Jamaica ;  New  Pro- 
\ddence. 

P.  incequale  (Grev.). — Front  view  with 
straight  sides ;  costae  four,  the  terminal 
ones  in  front  view  longer  than  the  cen- 
trical, and  inflected  at  their  apices ;  striae 


in  •OOl".     Grev  /.  c. 
New  Providence. 


p.  211,  pi.  10.  1 14. 


3*  Valves  with  more  than  four  costis. 

P.  Californicum  (Grev.).  — Valves  li- 
near, with  rounded  ends ;  costae  more 
than  four;  striae  18  in  001".  Grev  I  c 
p.  211,  pi.  10.  f.  15-17.  Californian 
guano. 


OF  THE  FRAGILARIE.E. 


775 


Doubtful  or  insufficiently  knomn 
Species. 

P.  kevis  (Greg.).  —  Front  view  witli 
slightly  but  sharply  dilated  ends  and  a 
minute  prominence  in  the  middle  of  each 
margin ;  costte  two  ?,  striae  delicate^  about 
48  in  -001".  =  Denficula  IcBvis,  Greg  Dial 


of  Clyde,  p.  22,  pi.  2.  f.  33.     Scotland. 
Side  view  unknown. 

P.  Himanticlium  (E.).  —  Front  view 
eight  times  as  long  as  broad,  with  the 
rounded  apices  slightly  3-lobed,  costse 
two  ?,  margin  striated.  =  Heteromphala 
Himantidium,'EP\BA..  1858, p.  13.  ^^gean 
Sea.     Side  view  unkno^Ti. 


Genus  ODONTIDIUM  (K.).  — Fmstiiles  united  into  a  filament;  lateral 
view  linear  elliptic  or  cruciform,  with  pervious  costae.  "  The  Odontidia  are 
merely"  a  filiform  series  of  Denticulne."  (Menegh.)  Like  Denticula,  this  genus 
is  distinguished  from  Fragilaria  by  its  strongly-marked  costae,  which  appear 
in  the  front  view  like  marginal  i^uncta.  The  filaments  are  usually  extremely 
fragile,  and  when  broken  up  the  frustules  scarcely  differ  from  those  of 
Denticula.  Smith  says,  "  It  must  be  acknowledged  that  there  is  little  to 
separate  these  genera ;  and  I  should  be  disposed  to  unite  the  two,  were  there 
not  in  the  general  habit  of  the  living  frustule  characters  which  enable  the 

observer  to  assign  them  to  their  respective  genera It  may  be  left  to 

futiu^e  observers  to  consider  whether  they  may  not  without  inconvenience  be 
united." 


Odoxtidii-im  mesoclon  (K.).  —  Has 
shorter  and  subquadi'ate  frustules,  with 
from  two  to  four  transverse  costse.  The 
last  character,  however,  is  so  inconstant 
that,  although  Professor  Smith  adopted 
it  in  his  definition,  almost  every  frustule 
in  his  figm-es  has  a  greater  nmnber.  O. 
c/laciale  often  has  trapezoid  frustules  and 
5  or  6  costte,  whilst  O.  turgidulum  is  in- 
termediate between  those  forms  and  the 
normal  frustules  in  length  and  number 
of  costae. 

0.  hyemale  (Lyngb.,  K.). — Front  view 
with  bead-like  marginal  pimcta ;  valves 
elliptic-oblong  or  elliptic-lanceolate,  ob- 
tuse, with  conspicuous  costae.  KB.  p.  44, 
t.  17.  f.  4;  SBD.  pL  34.  f.  289;  Fragi- 
laria hyemalis,  Lyngb.  t.  63 ;  F.  con- 
fervoides,  GBF.  ii.  p.  403 ;  F.  striata, 
EA.  p.  127;  Odontidium  turqidulum,  KB. 
t.  17.  f  2 ;  F.  turyidulwn,  E  Inf. ;  Odo?i- 
tidium  qlaciale,  KB. ;  O.  mesodon,  KB. 
t.  17.  £  3  ;  SBD.  ii.  p.  16.  Common. 
Europe,  Asia,  Australia,  and  America, 
(xiii.  24,  25.)  Odontidium  hyemale  is 
easily  distinguished  from  other  filamen- 
tous Diatoms  by  its  exceeding  fragility, 
minute  terminal  pmicta,  gland-like  mar- 
ginal ones,  and  the  conspicuous  costae  of 
the  valves.  The  frustules  var^^  much 
in  length  and  in  the  number  of  their 
costae ;  and  several  species  have,  we  be- 
lieve, erroneously  been  constituted  upon 
these  characters.  We  do  not  hesitate 
to  unite  them,  confirmed  in  our  opinion 
by  the  doubts  expressed  respecting 
their  distinctness  bv  the  late  Professor 
Smith. 


0.  Bogotanum  (Rab.).  —  Ver}-  small ; 
valves  oblong,  with  rounded  ends,  and 
from  2  to  4  very  broad  transverse  costae. 
Rab  Diat.  p.  34,  t.  2.  f.  8.  Bogota.  Ap- 
parently a  state  of  O.  hyemale. 

0.  capitatum  (Rab.).  —  Foiu*  to  six 
times  as  long  as  broad;  valves  lanceo- 
late, constricted  beneath  the  capitate 
apices ;  costae  6  or  7  in  1-1200".  Rab 
Diat.  p.  34,  t.  10.  f.  17.  =  O.  chamocepha- 
lum,  Rab  D.  p.  34,  t.  10.  f.  16 ;  Fragi- 
laria? capitata,  EB.  1853,  p.  527;  Microg. 
pi.  35  A.  12.  f.  2  ;  F.  ?  leptocephala,  E  /.  c. 
p.  527 ;  Microg.  pi.  35  a.  12.  f.  3.  Europe, 
Persia,  and  America. 

O.  nodulosum  (E.,  K.).  —  Frustules 
narrow  linear,  twelve  times  as  long  as 
broad;  valves  narrow  linear,  nodidose, 
constricted  beneath  the  capitate  ends; 
stri.'B  18  in  1-200".  KSA.  p.  13.  =  Fra- 
gilaria nodulosa,  EB.  1844,  p.  267.  Kur- 
distan. 

O.  jnnnatum  (E.,K.). — Frustules  three 
to  six  times  longer  than  broad ;  valves 
with  rounded,  not  attenuated,  ends, 
and  25  strong  strige  in  1-1200".  KSA. 
p.  13.  =  Fragilaria  p>innata,  EB.  1844, 
p.  202  ;  Microg.  t.  35  a.  22.  f.  8.  Ant- 
arctic Sea. 

O.  minimum  (Nag.). — Very  small; 
valves  trapezoid,  \\dth  acute  apices  and 
very  faint,  nearly  obsolete  transverse 
striae ;  fr-ont  view  quadrate,  with  margi- 
nal puncta.  KSA.  p.  889.  =  O.  Salishur- 
gense,  Rab  D.  p.  38,  t.  2.  f.  7.     Em-ope. 

O.  rotundatum  (E.,  K.).  —  Frustules 
often  nine  times  as  long  as  broad  ; 
valves   linear,  with  rounded  ends,  and 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


20  stout  cost^  in  1-1200".  KSA.  p.  13.  I 
=  FraqUana  rofwidata,  EB.  1844,  p.  202 ;  ' 
EM.  pi.  1.  1.  £  1.  Fossil.  Pliilippine  | 
Islands. 

O.jnnnatinn  (E.,  K.). — Friistules  three 
to  six  times  as  long  as  broad;  valves 
linear,  with  rounded  ends,  and  15  stout 
costc^  in  1-1200".  KSA.  p.  13.  =  Fm- 
gilaria  puinata,  EA.  p.  127;  Microg. 
many  figm-es,  Australia,  Africa,  and 
America.  Akin  to  O.  striatum  and  O. 
Syriacum,  E. 

O.  striolatum  (E.,K.). — Frustules  three 
to  six  times  as  long  as  broad;  valves 
linear,  constricted  beneath  the  obtuse 
capitate  ends;  striee  about  18  in  1-1200". 
KSA.  p.  13.  =  Frayilaria  striulata,  EM. 
t.  28.  f.  58.  Europe  and  Australia.  Ehr- 
enberg's  figures  in  the  '  Microgeologie ' 
have  the  ends  slightly  attenuated,  and 
not  capitate. 

0.  Syriacum  (E.,  K.). — Frustules  eight 
times  as  long  as  broad ;  valves  with  10 
stri«  in  1-1200".  KSA.  p.  13.  =  Fra- 
yilaria Syriaca,  EB.  1810,  p.  16.    Syria. 

O.  ?  ])ohjedrum  (E.  K.).  —  Frustules 
oblong,  angular  (sexangular  ?) ;  three 
times  as  long  as  broad ;  strise  very 
fine.  KSA.  p.  14.  =  Frayilaria  polyeclra, 
EB.  1845,  p.  77.  Fossil.  America. 
1-900". 

O.  amiMceros  (E.,  K.). — Valves  turgid 
at  the  middle,  with  elongated,  linear, 
trmicate  ends  and  pervious  striae.  KSA. 
p.    13.   =  Frayilaria    ampliiceros,     EB. 


1844,  p.  82;  Microg.  t.  18.  f.  77.  Vir- 
ginia. 

O.  yranulatum  (E.,  K.).  —  With  the 
habit  of  O.  amphiceros,  but  smaller; 
valves  with  attenuated  ends  and  granu- 
lated fascias  in  striae.  KSA.  p.  13.  = 
Frayilaria  yramdata,  EB.  1844,  p.  202. 
Antarctic  Sea. 

0.?  G^Z«;zs(E.,K.). — Frustules  striated, 
short,  gibbous  at  the  middle,  constricted 
at  the  obtuse  ends,  and  resembling  the 
figure  of  an  acorn  with  its  calvx ;  striae 
2  or  3  in  1-1200".  KSA.  p.  U.  =  Fra- 
qilaria  Glans,  E  Inf.  p.  185.  Fossil. 
Finland.     1-1150"  to  1-570". 

O.  anomahan  (S.). — Filament  tena- 
cious ;  valves  linear,  suddenly  constricted 
towards  the  roimded  extremities ;  costae 
four  to  twelve.  SBD.  ii.  p.  16,  pi.  61. 
f.  376.  Alpine  situations.  Europe.  Front 
^dew  with  punctate  or  denticulate  mar- 
gins. Internal  cells,  similar  to  those  met 
with  in  Meridion  and  Himantidium,  are 
frequent  in  this  species. 

O.  ancejjs  (E.). — SmaU;  valves  linear- 
oblong,  constiicted  beneath  the  subcapi- 
tate  apices.  =  Fraqilaria  anceps,  EA. 
p.  127 ;  F.  Pteridium,  EM.  pi.  34.  5  b. 
f.  10  ?     North  America. 

O.  Cretce  =  Fraqilaria  Cretce,  EM. 
pi.  53. 17.  f.  9  ;  F.paradoxa,  EM.  pi.  33. 
15.  f.  13  ?  Australia,  Europe,  and  Africa. 
Valves  linear-oblong,  with  rounded  ends 
and  pervious  transverse  costae. 


Genus  FEAGILARIA  (Lyngb.,  K.).- — Frustules  linear,  united  into  a  fila- 
ment ;  lateral  valves  smooth  or  faintly  striated,  linear-lanceolate  or  fusiform. 
Fragilaria  differs  from  Odontidium  in  the  absence  of  costa) ;  and  the  strice, 
which  are  probably  present  in  all  the  species,  are  so  obscure  that  Klitzing 
makes  theii'  absence  one  of  the  generic  characters.  Diadesmis  may  be  distin- 
guished from  Fragilaria  by  the  presence  of  a  central  nodule  in  the  lateral 
valves.  Professor  Smith  justly  regrets  that  in  the  subdivision  of  Fragilaria 
sufiicient  regard  has  not  been  paid  to  the  signification  of  the  generic  name. 
We  consider  that  it  would  have  been  far  better  to  have  retained  the  name 
for  Fragilaria  hyemalis,  Lyngb.  (  =  Odontidium,  K.),  so  remarkable  for  its 
fragility. 


Feagilaeia  capucina  (Desni.). — Front 
view  naiTow  linear,  with  obsolete  or  ob- 
scure terminal  puucta;  valves  lanceolate ; 
striae  obscure.  KB.  p.  45,  1. 16.  f.  3.  = 
F.  pectinalis,  Ljaigb.  t.  63;  Ag  Consp 
Diat.  p.  62 ;  F.  ^tenuis,  Ag  Consp  Diat. 
p.  63  ;  F.  Rhahdosoma,  diojihthalma,  mul- 
tipuncfata,  hipunctata,  am/usta,  scalaris, 
and  Jissa,  E  Inf.  F.  sepes,  EM.  t.  38.  1. 
f.  8.  Common,  but  generally  in  small 
quantities  and  mixed  wdtli  other  Diatoms. 
Europe,    Asia,    Australia,    Africa,    and 


America,  (ix.  173,  174.)  A  very  vari- 
able species.  The  fi-ustules  are  so  much 
compressed  that  it  is  difticidt  to  obtain 
a  good  view  of  the  valves ;  but  it  may 
usually  be  recognized  in  the  fi-ont  view 
by  its  obsolete  tenninal  puncta.  When 
dried,  it  has  a  silvery  lustre.  Filaments 
elongated. 

F.  acuta  (E.).— Valves  linear,  with 
acutely  cuneate  apices ;  striae  wanting  or 
obscure ;  front  view  linear.  E  Meteorp. 
t.  2.  f.  10;  Microg.  many  figures.  = -F.  ea- 


OP  THE  FEAGILAEIEJE. 


77 


pucina,  SBD.  pi.  35.  f.  296.  Europe, 
Asia,  Africa,  and  America.  1-1152"  j 
six  times  longer  than  broad. 

F.  corriKjata  (K.). — Minute ;  frustules 
geminate,  corrugated  at  each  end  ;  valves 
acutely  lanceolate.  KB,  p.  45,  t.  16.  f.  5. 
Germany.     1-1440". 

F.  pusilla   (K.).  —  Glassy  ;   frustules 
rectangular,  quadrate,  or  linear,  united  | 
in   very   short    fascias ;   valves    naiTow 
linear, "  smooth.     KSA.  p.  14.     Marine. 
France. 

F.  Bacillum  (E.).  —  Valves  smooth, 
linear  wdtli  roimded  ends,  five  or  six 
times  as  long  as  broad.  EB.  1844 ; 
Microg.  pi.  21.  f.  30  &  pi.  35.^16.  f.  11. 
Fossil.     Oran  and  Virginia.   1-720". 

F.  glabra  (E.). — Linear,  smooth,  with 
attenuated  obtuse  apices.  EA.  p.  127. 
Guiana.  May  be  a  variety  of  F.  bi- 
ceps, E. 

F.  Catena  (E.). — Twice  as  long  as 
broad ;  valves  oblong,  smooth.  EB. 
1840,  p.  16.  =  F.  tw-gens,  EM.  several 
figures  ?  Europe,  Africa,  and  Mexico. 
1-1152". 

F.  virescens  (Ralfs).  —  Valves  turgid 
lanceolate,  suddenly  contracted  towards 
the  obtuse  ends ;  striae  44  in  -001",  verv 
faint.  Ralfs,  Ann.  xii. ;  SBD.  ii.  p.  22, 
pi.  35.  f.  2d7.  =  Diatoma  virescens,  HBA. 
F.  pectinalis,  E.  Streams.  Europe.  Fila- 
ments elongated,  lurid-green ;  frustules 
rather  broad,  with  distinct  terminal 
puncta,  frequently  irregularly  adhering 
by  their  angles  like  a  Diatom.  Easily 
recognized  by  its  greenish  hue  when 
growing. 

F.  Venter  (EM.  several  figures).  — 
Minute ;  valves  smooth,  t^dce  as  long- 
as  broad,  oblong  lanceolate,  with  con- 
tracted, produced,  obtuse  ends. 

F.  mesotyla  (E.). — Bacillar  with  tur- 
gid centre,  obtuse  ends,  and  transverse 
granular  striee.  Asia.  1-480".  Resembles 
Stauroneis  granulata,  but  wants  the  lon- 
gitudinal band  and  crucial  umbilicus,  E. 

F.  Jcevis  (E.). — Resembles  Oclontidium 
amphiceros,  but  is  without  the  dotted 
striae.     EA.  p.  127.     Virginia. 

F.  bicejys  (E.). — Valves  linear  oblong, 
suddenly  constricted  at  the  ends  into 
minute  beaks ;  strias  wanting  or  obscure. 
EA.    p.  127;   Microg.    several    figures. 


z=F.  gibba,  EM.  pi.  33.  17.  f.  9  ?  Ame- 
rica and  Europe. 

F.  binodis  (E.).  —  Parasitic,  mostly 
simple  ;  valves  rostrate,  sometimes  con- 
stricted, sometimes  inflated  at  the  middle; 
striae  wanting  or  obscure.  EA.  p.  127 ; 
Microg.  pi.  5.  2.  f.  26.  =  Odontidium  ?  pa- 
rasiticiim,  SBD.  ii.  p.  19,  pi.  60.  f.  375. 
Em'ope  and  America.  /3  inflated,  with- 
out a  central  constriction.  S  /.  c.  p.  375. 
Frustules  rarely  cohering,  and  scarcely 
silicious.     S. 

F.  constricta  (E.).  —  Frustules  fre- 
quently cohering  by  their  angles ;  valves 
rostrate,  subacute,  in  general  slightly 
constricted,  sometimes  inflated  at  the 
middle ;  striae  faint,  42  in  -001".  EA. 
p.  127;  Microg.  several  figures.  =  F. 
undata,  SBD.  ii.  p.  24,  pi  60.  f.  377. 
/3,  valves  turgid  at  the  middle,  S.  Eu- 
rope, Asia,  Australia,  and  America. 

F.  Fntomon  (E.).  — Valves  elongated, 
smooth,  strongly  constricted  at  the 
middle,  with  rostrate  ends.  EA.  p.  127 ; 
Microg.  pi.  6.  3.  f.  52.     North  America. 

F.  binalis,  EM.  pi.  14.  f.  52.  Germany 
and  Maiuitius.  Valves  smooth,  con- 
stricted at  the  middle,  and  roimded  at 
the  ends. 

Doubtful  and  undescribed  Species  from 
FJlirenberg. 

F.  ?  Tessella,  EM.  pi.  20.  2.  f.  29. 
Broadly  and  sharply  lanceolate  without 
markings. 

F.  ?  Synedra,  EM.  pi.  39.  3.  f.  60,  61. 
Frustules  united,  curved ;  venter  gibbous 
at  centre. 

F.  ?  Mesogongyla,  EB.  1856,  p.  333, 
f.  48.  Africa.  Valves  ^\dth  minute  in- 
flated middle,  and  slender  acute  rostrate 
ends. 

F.  oxyrluanbus,  EB.  1856,  p.  333, 
f.  44,  Africa ;  F.  Trachea,  Australia ;  F. 
seininuda,  fossil,  Georgia ;  F.  ventralis, 
Anatolia  ;  F.  Himalayce,  India  ;  F.  ? 
Stylus,  ^gina ;  F.  ?  Stylidium,  ^gina ; 
F.  ?  tmdulatum,  Asia ;  F.  Crux,  Asia ; 
F.  Tcenia,  Africa ;  F.  amphilepta,  Africa ; 
F.  Lamella,  Australia;  F.  amphicephala, 
Asia ;  F.  ventricosa,  Africa ;  F.  frus- 
tulia,  America ;  F.  Funotia,  Africa ;  F. 
thermalis,  America;  F.  austral  is,  Ame- 
rica; F.  Pumerooni,  America. 


Genus  GRAMMONEMA  (Ag.). — Frustules  similar  to  those  of  Fragilaria, 
but  scarcely  silicious,  and  united  into  flexible,  highly  mucous  filaments. 
"  Grammonema  in  appearance  comes  very  near  to  Fragilaria ;  but  its  habit  is 
so  very  different  that  I  am  inclined,  with  Agardli,  to  keep  them  distinct.  In 
Fragilaria  the  filaments  do  not  adliere  well  to  paper,  the  frustules  are  silicious 
and  may  be  subjected  to  a  red  heat  without  an}-  other  alteration  than  tlic 


vv. 


SYSTEMATIC  HISTORY  OF  THE  INFUSO-RIA, 


destruction  of  the  colouring  matter,  and  at  each  end  are  two,  more  or  less 

distinct,  pellucid  puncta In  Grammonema  there  is  scarcely  any  sihca, 

and  the  filaments  are  not  fragile,  but  highly  mucous,  adhering  firmly  to  paper 
or  glass,  and  when  dried  appearing  hke  a  mere  stain ;  the  application  of  nitric 
acid  or  of  a  red  heat  destroys  their  form,  and  I  can  perceive  no  pimcta  at  the 
ends  of  the  frustules."  Ralfs,  Ehrenberg,  and  Kiitzing  place  this  genus  with 
the  Desmidieae  because  of  the  absence  of  silica ;  and  Meneghini  says,  "  I  think 
this  conclusion  right.  It  is  a  true  Desmidiean,  for  it  has  no  silicious  shield ; 
and  it  is  to  be  observed  that,  however  perfectly  it  may  resemble  the  Fragi- 
larieae  in  form,  it  wants  the  longitudinal  canals  and  terminal  perforations  of 
the  primary  surfaces." 


Grammonema  Jurgensn  (Ag.).  — 
Valves  oblong  lanceolate,  slightly  con- 
stricted at  the  obtuse  ends.  Ag  CD. 
p.  63.  =Fragilaria  Jurf/ensii,  KSD.  p.  59 ; 
Cottferva  striatida,  Jurg. ;  Fragilaria 
striatula,  Lyngb  Hyd  Dan.  p.  183,  t.  63 ; 
SBD.  ii.  pi.  23.  f.  298;  Grammatonema 
stnatidum,  KSA.  p.  187;  Arthrodesmus 
striatulus,  ERBA.  1840;  Frmjdaria  au- 


rea,  Cserm.  in  Hook  B  Fl.  ii.  p.  403. 
/3.  diatomoides,  filaments  tm'uing  greenish 
when  dried,  =  Fragilaria  diatomoides, 
Grev.,  Hook  B  Fl.  p.  403.  On  marine 
Alg?e.  Spring,  Europe,  (xv.  24,  25.) 
Grammonema  Jurgensii  is  easily  distin- 
guished from  every  species  of  Fragilaria 
by  its  marine  habitat  and  flexible,  highly 
mucous  filaments. 


Genus  DIATOMA  (Dec).  —  Frustules  quadi^angular,  partially  separating, 
and  cohering  by  the  angles  (generally  by  the  alternate  ones)  into  a  zigzag 
chain.  Diatoma  is  distinguished  from  Fragilaria  and  Odontidiimi  by  the  con- 
nexion of  the  frustules  at  their  angles  in  a  zigzag  chain.  Some  species  of 
Fragilaria,  indeed,  have  a  few  frustules  similarly  adhering ;  but  this  is  a  con- 
stant character  in  Diatoma,  whilst  the  greater  number  of  their  frustules  will 
present  the  usual  appearance  of  a  Fragilaria.  Meneghini  says,  "  For  my  part, 
I  think  it  would  be  much  m.ore  natural  to  place  the  smooth  species  {D.  pec- 
tinale,  D.  vitreum,  and  Z>.  hiiaJinum)  in  Fragilaria  ;  those  striated  with  elliptic- 
lanceolate  surfaces  {D.  vulgare,  D.  mesodon,  D.  tenue,  and  B.  mesolej^tum)  in 
Odontidium.  There  would  remain  as  distinctly  generic  the  species  which 
have  capitate  extremities  on  their  lateral  surfaces.  These  unions  woidd  be 
justified  on  both  sides ;  for  whilst  the  Odontidia  have  forms  little  different 
from  Diatoma,  Diatomata  are  httle  difi'erent  from  Fragilaria." 


*  StricB  obsolete. 

Diatoma  hyalinmn  (K.).  —  Frustules 
elongated,  very  hyaline;  valves  linear 
lanceolate,  with  rather  obtuse  apices ; 
striae  obsolete.  KB.  p.  47,  t.  17.  f.  20 ; 
SBD.  ii.  pi.  41.  f  312.  Marine.  Europe. 
(IV.  16.) 

D.  minimum  (Ealfs). — Frustides  mi- 
nute, very  hyaline;  valves  about  twice 
as  long  as  broad,  oblong  with  rounded 
ends ;  striae  obsolete.  Ralfs,  T  Bot  Soc. 
2nd  ed.  p.  20 ;  SBD.  ii.  p.  41,  pi.  41.  f  313. 
=  Z).rjYre?««,  KB.  p.47.  Marine.  Europe. 

D.  pectinale  (Nitz.,  K.). — Frustides  at 
first  forming  a  fascia,  afterwards  zigzag ; 
valves  acutely  lanceolate ;  striae  obsolete. 
KB.  p.  47,  t.'l7.  f  11.  =  Bacillaria  pecti- 
7mlis,  Nitz  ;  B.  seriata,  Ptolemai,  Jioceu- 
losa,  E  Inf.  Fresh  water.  Egypt,  Eu- 
rope, England. 


2  *  Strioi  (costce)  evident. 

D.  rid  gar  e  (Bory)c  —  Valves  spindle- 
shaped,  suddenly  contracted  at  the  ob- 
tuse ends ;  costae  pervious,  conspicuous, 
about  18  in  001".  KB.  t.  17.  f  15;  SBD. 
p.  39,  pi.  40.  f.  309  ;  Bacillaria  vulgaris, 
E  Inf.  p.  197 ;  Diatoma  tenue,  Grev., 
HBFl.  p.  406;  D.  Jloccidosum,  A^CVf. 
p.  53.  Europe,  Asia,  Africa,  and  Ame- 
rica. Frustules  three  or  four  times  as  long 
as  broad.  This  species  is  distinguished 
by  the  greater  breadth  and  convexity  of 
its  frustides,  and  by  the  conspicuous 
marginal  puncta  of  the  front  view, 
(iv.  13 ;  IX.  168.) 

D.  mesodon  (K.).  —  Valves  ventricose 
lanceolate,  with  three  to  five  transverse 
stria?  at  the  middle.  KB.  p.  47,  1. 17. 
f  13.  (:i.  euneatum,  frustides  cuneate. 
KB.  t.  17.  f  12,  =  Bacillaria  cuneata,  E 


OF  THE  FRAGILARIE^. 


779 


Inf.  t.  15.  f.  6 ;  Diatoma  cimeatum,  Rab 
D.  t.  2.  f.  4.  Germany,  (ix.  170.)  Pro- 
bably a  state  of  D.  vulgare. 

D.  tenue  (Ag.).  —  Valves  lanceolate, 
with  from  9  to  12  distinct  striae  in 
1-1200".  Ag  CD.  p.  52 ;  KB.  p.  48,  t.  9. 
f.  10.  =  BaciUaria  pectmalis^  E  Inf.  p.  198, 
t.  15.  f.  4.  Europe  and  Asia.  A  protean 
species ;  the  fi-ustules  are  sometimes  qua- 
drate, sometimes  linear,  and  sometimes 
cuneate. 

D.  mesoleptum(K.). — Frustules  slightly 
attenuated  at  the  middle ;  valves  lanceo- 
late, with  from  10  to  12  striae  in  1-1200". 
KB.  p.  48,  1. 17.  f.  16.  Europe.  1-650". 
We  fear  it  is  scarcely  distinct  from  D. 
tenue. 

D.  Ehrenherciii  (K.). — Front  view  at- 
tenuated at  the  middle;  valves  linear 
lanceolate,  contracted  beneath  the  sub- 
capitate   apices;    costas    11   in  1-1200". 


KB.  p.  48, 1. 17.  f.  17 ;  SA.  1857,  xix.  p.  10, 
pi.  1.  f.  13.  =  BaciUaria  elongata,  E  Inf. 
p.  198,  t._15.  f.  5.  Europe,  (ix.  169.) 
The  inflation  in  the  centre  of  the  valve 
separates  this  species  from  D.  grande, 
which  is  moreover  a  larger  form  with 
coarser  striae,  S,    (iv.  15.) 

J},  grande  (S.). — Valve  linear,  con- 
stricted beneath  the  capitate  apices ; 
costfe  24  in  -001".  SBD.  ii.  p.  39,  pi.  40. 
f.  310.  =  Baci/laria  australis,  EM.  pi.  35. 
A  2.  f.  3.  Britain,  Africa,  and  South 
America. 

1).  elongatum  (Ag.). — Valves  linear, 
with  inflated,  capitate  apices ;  costae  7  in 
1-1200".  KB.  p.  18,  t.  17.  f.  18 ;  SBD. 
ii.  p.  40,  pi.  40.  f.  311.  =  Diatoma  gracil- 
limum,  Nag.,  KSA.  p.  889.  Em-ope. 
Front  view  slender,  attenuated  at  the 
middle,    (iv.  14;  ix.  119.) 


Genus  ASTEBIONELLA  (Hass.).  —  ''  Friistiiles  linear,  inflated  towards 
one  or  both  extremities ;  adhering  by  their  adjacent  angles  into  a  star-like 
filament"  (SBD.  ii.  p.  81).  The  frustules  in  this  genus  exactly  resemble 
those  of  the  capitate  species  of  Diatoma,  but  are  few  in  number ;  and  being 
connected  by  the  adjacent  angles,  the  free  extremities  diverge  in  a  stellate 
manner.  We  first  observed  a  single  specimen  amongst  some  freshwater  Algae 
gathered  near  Dublin  by  Mr.  D.  Moore,  and  afterwards  obtained  it  plentifully 
for  two  successive  years  in  a  pool  near  DolgeUy,  when  we  considered  it  a 
species  of  Diatoma  nearly  allied  to  D.  tenue.  Subsequently  we  received  a 
larger  form  from  Professor  Dickie,  gathered  near  Aberdeen.  The  Scottish 
form  had  the  free  end  truncated,  and  is  probably  the  one  described  by 
Professor  Smith  as  A.  Balfsii. 


AsTEBiONELLA  fomiosa  (Hass.).  — 
Front  view  somewhat  more  enlarged  at 
the  base  than  at  the  summit.  -0024"  to 
•0031".  SBD.  ii.  p.  81.  Fresh  water. 
Britain,     (iv.  17.) 

A.  Bleakeleyii  (S.). — Frustules  linear, 
enlarged  at  the  base.  -0022".  SBD.  ii. 
p.  82.     Marine.     England. 


{      A.  Balfsii  (S.).  —  Frustules   in  front 

view  exactly  linear ;  valve  attenuated  at 

one  end,  constricted  towards  the  other, 

:  which  is  rounded   and   capitate;    stria9 

I  obscure.     SBD.  ii.  p.  81.  =  Diatoina  stel- 


lare,  BO.  p.  39.     Fresh  water, 
and  America,    (iv.  18.) 


Europe 


Genus  NITZSCHIA  (Hass.,  Smith). — ''  Frustules  free,  elongated,  com- 
pressed ;  valves  linear,  keeled,  with  one  or  more  longitudinal  lines  of  puncta  ; 
keel  frequently  eccentric.  .  .  .  This  genus  embraces  a  large  number  of  species, 
diftering  in  form  and  size,  but  aU  agreeing  in  a  few  general  characters.  The 
most  important  of  these  is  the  keeled  form  of  the  valves  and  the  remarkable 
inequality,  in  many  of  the  species,  between  the  portions  of  the  valve  Ipng  on 
either  side  of  this  prominency.  This  inequality  (or,  in  other  words,  this 
eccentricity)  of  the  keel  distinguishes  Mtzschia  from  Amphiprora,  in  which  the 
keel  is  also  present ;  while  the  presence  of  a  keel  and  its  accompanpng  line 
or  lines  of  puncta,  together  with  the  absence  of  any  form  of  stipes,  separate 
the  present  from  the  genus  SjTiedi^a."  Professor  Smith,  whose  generic  cha- 
racter and  remarks  we  have  quoted,  has  brought  together  forms  from  several 
genera,  and  thus  has  not  only  pointed  out  the  remarkable  character  which  is 
common  to  them  all,  but  also  relieved  those  genera  of  members  which  ill 


780 


SYSTEMATIC  HISTOHY  OF  THE  INFUSORIA. 


agreed  vnth  their  definitions.  It  is,  however,  probable  that  his  characters 
may  rather  belong  to  a  family  than  to  a  single  genus,  his  sections  forming 
genera.  The  sigmoid  forms  were  placed  by  Ehi-enberg  in  ]N"avicula,  and  by 
Kiitzing,  in  his  earlier  work  (Kiescl.  Bacil.),  in  Synedra.  Subsequently,  how- 
ever, in  his  '  Species  Algarum,'  Klitzmg  removed  them  from  Synedra,  and,  under 
his  old  name  of  Sigmatella,  placed  them  with  the  Pragilarieae  because  they  are 
not  affixed  and  have  pervious  transverse  striae. 


*  Minute :  front  view  strait ;  valves  ar- 
cuate tvith  a  row  of  dots  on  the  ventral 
mar  (/in. 

NiTzscHiA  ampldoxys  (E.).  —  Valve 
linear  lanceolate,  arcuate,  with  convex 
dorsum,  concave  venter,  and  attenuated, 
subrostrate,  acute  apices;  strite  30  in 
•001",  terminating  in  dots  at  the  ventral 
margin.  SBD.  i.  p.  40,  pi.  13.  f.  105. 
=  Eunotia  amphioxys,  EA.  p.  125.  Fresh 
water,  very  common.  Ehreuberg  gives 
upwards  of  200  habitats  in  Europe,  Asia, 
Australia,  Africa,  and  America. 

N.  vivax  (S.).  —  Valve  linear  lan- 
ceolate, arcuate,  with  rostrate  apices ; 
striae  distiuct,  30  in  -001",  terminat- 
ing in  marginal  dots.  SBD.  i.  p.  41, 
pi.  31.  f.  267.  Fresh  or  brackish  water. 
England. 

N.  parvula  (S.). — Valve  with  central 
constriction,  obscure  puncta,  and  pro- 
duced apices ;  striee  faiut,  70  in  -001". 
SBD.  i.  p.  41,  pi.  13.  £  106.  Marine. 
Sussex. 

N.  minutissima  (S.).  — Valve  linear, 
with  distinct  puncta  and  prominent 
acute  apices  ;  striae  obscure,  72  in  -001". 
SBD.  i.  p.  41,  pi.  13.  f.  107.  Fresh 
water.     Beachy  Head. 

^.Biance  (E.). — Valve  linear,  arcuate, 
with  convex  dorsum,  concave  venter,  and 
produced  slightly  reflexed  apices  ;  striae 
13  in  1-1200",  terminating  in  dots  on 
the  ventral  margin.  =  JEunotia  Biance, 
ERBA.  1840,  p.  14;  Microg.  pi.  35  a. 
2.  f.  9.  Fresh  water.  Europe,  Asia, 
Africa,  and  America. 

N.  amjyJiikpta  (E.). — Valve  linear, 
arcuate,  with  convex,  smooth  dorsum, 
slightly  concave,  striated  ventral  margin, 
and  acute,  gradually  attenuated,  slightly 
reflexed  apices.  =  JEunotia  ainjjJitlcpta, 
ERBA.  1845,  p.  363;  Microg.  pi.  34.  8. 
f.  4.     Japan  and  China. 

N.  virgata  (Roper).  —  Valve  linear 
lanceolate,  slightly  arcuate,  with  pro- 
duced, slightly  recurved,  obtuse  apices  ; 
stiiae  distinct," 26  in  -OOl',  dilated  at  in- 
tervals into  ridges  on  the  ventral  margin. 
Roper  JMS.  vi.  p.  23,  pi.  3.  f.  6.  Ma- 
rine. Tenby.  Diflers  from  N.  ampJii- 
oxys  and  N.   vivax  by  the  strife  being 


dilated  into  bands  instead  of  terminating 
in  puncta,  Roper. 

2  *  Frustules  constricted  at  the  middle, 

N.  constricta  (K.). — Front  view  ob- 
long, slightly  constricted  at  the  middle 
and  tapering  towards  the  somewhat 
truncate  ends  ;  keel  very  eccentric  ;  striae 
obscm'e,  60  in  -001".  =  Synedra  con- 
stricta, KB.  p.  64,  t.  3.  f.  70 ;  Nitzschia 
duhia,  SBD.  i.  p.  41,  f.  112.  Marine. 
Europe. 

N.  Bntoinon  (E.). — Elongate,  thick, 
striate,  oblong  with  constricted  middle 
and  obtusely  cuneate  ends.  =  Synedra 
Untomon,  EM.  pi.  34.  2.  f.  5.  Em-ope, 
Asia,  Australia,  Africa,  and  America. 

N.  2j/«;irt  (S.).  —  Front  view  linear 
lanceolate,  with  attenuated  middle  and 
acutely  cuneate  ends  ;  valves  acutely 
linear  lanceolate,  mth  a  single  row  of 
puncta  and  56  obscure  striee  in  -001. 
SBD.  i.  p.  42,  pi.  15.  I  114.  Brackish 
water.     Europe. 

N.  Brlyhtwellii  (Kitton).  —  Valves 
broad  linear- oblong,  with  obtuse,  shortly 
attenuated  ends,  slightly  constricted 
middle  and  interruptedly  striate  margin ; 
surface  imder  a  low  power  granular, 
under  a  higher,  punctato-striate  ;  strife 
transverse,  25  to  30  in  -001".  Brackish 
water.  Sien'a  Leone.  Kitton  in  lit. 
(viii.  7.) 

N.  latestriata  (Breb.). — Front  view 
large,  broad  linear-oblong,  with  a  central 
constriction  and  broadly  rounded  ends  ; 
valves  narrow  lanceolate,  with  a  central 
keel,  double  row  of  puncta  and  56  di- 
stinct strife  in  -001" .  =  Aniphiprora  late- 
striata, Breb.  in  KSA.  p.  93 ;  Nitzschia 
hilohata,  SBD.  i.  p.  42,  pi.  15.  i.  113. 
Marine.     Europe. 

N.  panduriformis  (Greg.).  — Broad 
linear-oblong,  ^\dth  constricted  middle, 
acuminate  ends,  and  punctuated  mar- 
gins ;  striae  fine,  about  48  in  -001",  trans- 
verse and  oblique,  GDC.  p.  57,  pi.  6. 
f  102.  Marine.  Scotland.  There  is  a 
faint  indication  of  a  double  keel  in  the 
middle  of  the  valve.  The  striation  is 
similar  to  that  of  Tryblionella  constricta ; 
but  the  present  form  is  larger,  and  di- 
stinguished by  marginal  puncta  :  still  it 


OF  THE  FRAGILARIE-E. 


781 


resembles  a  Trvblionella  about  as  miicli 
as  it  does  a  Nilzscliia,  Greg. 

3  *  Front  vieiv  sigmoid  (Sigmatella, 
Kii'tz.). 

N.  sigmoidea  (Xitzscli,  S.).  —  Front 
A-iew  elongated,  broadly  linear,  sigmoid 
with  truncate  ends  and  marginal  pimcta ; 
valves  narrow  linear-lanceolate,  ^^tli 
tapering  ends  and  a  single  longitudinal 
seiies  ofpuncta  ;  strife  85  in  -001".  SBD. 
i.  p.  38,  pi.  13.  f.  10-^.  =  Kavicula  sig- 
moidea, EI.  t.  13.  f.  15;  Syncdra  sig- 
moidea, KB.  p.  67  ;  Sigmatella  JVitzschia, 
KSA.  p.  18 ;  Nitzscliia  elongata,  Hassall, 
B  Alg.  p.  435.  Fresh  water.  Europe. 
(rx.  148.)  Large,  with  elegantly  punc- 
tate margins.  The  strife  in  this  Diatom 
are  sometimes  strong  and  easily  seen, 
while  others  in  the  same  slide  set  at 
defiance  every  method  of  illumination  to 
bring  them  out.  Mr.  SoUitt,  of  Hull, 
says,  "  The  striae  vary  from  65  in  the 
•001"  up  to  a  degree  of  fineness  which 
no  lenses  that  we  now  have  will  show." 

N.  Brehissonii  (Klitz.,  S.). — Front  view 
broadly  linear,  sigmoid  with  truncate 
ends  and  marginal  puncta ;  valves  linear, 
with  attenuated,  obtuse  apices ;  striie  27 
in  -001".  SBD.  i.  p.  38,  pi.  31.  f.  266. 
=  Synedra  Armoricami,  KB.  t.  4.  f.  34 ; 
Sigmatella  Brehissonii,  KSA.  p.  18, 
France,  England.  Resembles  N.  sig- 
moidea, but  is  much  broader  in  propor- 
tion to  its  length,  the  puncta  are  more 
conspicuous,  and  the  lateral  view  is  more 
linear.  According  to  Professor  Arnott, 
this  species  is  not  the  Sigmatella  Bre- 
hissonii of  Kiitzing,  the  latter  beino-  a 
mere  variety  of  N.  sigmoidea,  whilst 
Smith's  species  is  distinct  and  a  brackish- 
water  species. 

N.  macilenta  (Greg.).  — Front  view 
elongated,  linear,  siginoid,  trimcate ; 
valves  linear  lanceolate,  with  acute  api- 
ces ;  keel  with  a  single  row  of  subremote 
puncta  ;  strife  verv  obscm*e.  Grev  MJ. 
vii.  p.  83,  pi.  6.  f.  8,  9.  Marine.  Scot- 
land. Allied  to  N.  sigmoidea,  but  de- 
cidedly less  sigmoid.  The  side  view 
very  narrow ;  puncta  separated  from  each 
other  by  iiTegular  intervals,  and  fewer 
(8  in  'OOl")  than  in  N.  sigmoidea,  Gre- 
ville. 

N.  Sigma  (K.,  S.). — Front  view  sig- 
moid, linear  lanceolate,  gTadually  taper- 
ing to  the  truncated  apices;  keel  of  valves 
^^■ith  a  double  row  of  puncta.  SBD.  i. 
p.  39,  pi.  13.  f.  108.  =  Synedra  Sigma,  KB. 
p.  67,  t.  30.  f.  14.  Marine.  Em^ope. 
Strire  56  in  -001",  S.    (iv.  20.) 

N.  Sigmatella  (Greg.). — Front  viewsig- 


moid,  linear  lanceolate,  gradually  taper- 
ing to  the  obtuse  apices  ;  valves  linear, 
acute,  with  obscure  strife.  Greg  MJ.  iii. 
p.  4,  f.  2.  =  N.  curvida,  SBD.  ii.  p.  39. 
Fresh  water.  Europe.  Distinguished 
from  N.  Sigma  by  its  far  more  delicate 
sti'ife  and  freshwater  habitat.  Professor 
Kiitzing  describes  the  Navicula  curvula 
as  straight  in  the  front  and  sigmoid  in 
the  lateral  view ;  it  is  therefore  probably 
a  Plem^osigma,  and  not  this  species,  as 
supposed  by  Smith. 

N.  vermicularis  (K.). — Front  view  sig- 
moid, slender,  linear  or  slightly  dilated 
at  the  middle  ;  striae  6h&Qm:e.=  Synedra 
vermicularis,  KB.  t.  4,  f.  35  ;  Sigmatella 
vermicularis,  KSA.  p.  18.  Fresh  water. 
Em'ope. 

N.  Tergestina  (K). — Front  ^lew  sig- 
moid, linear,  truncate ;  valves  naiTow 
linear,  ^\dth  suddenly  contracted,  pro- 
duced apices.  =  Synedra  Tergestina,  KB. 
p.  66,  t.  4.  f.  33;  Sigmatella  Tergestina, 
Rab  D.  p.  56.  Europe.  11  striae  in 
1-1200",  Bab. 

N.  Italica  (Eab.). — Front  view  broad- 
ly linefir,  slightly  sigmoid,  truncate ; 
valves  sigmoid,  with  attenuated  rounded 
ends,  and  9  striae  in  1-1200".  =  Si fpnatella 
Italica,  Eab  D.  p.  56,  t.  4.  f.  12.    Italy. 

N.  ohtifsa  (S.). — Front  view  sigmoid, 
linear,  with  rounded  apices ;  valves  linear, 
obtuse,  ^\dth  a  double  series  of  puncta ; 
striae  56  in  -001".  SBD.  i.  p.  39,  pi.  13. 
f.  109.  Brackish  water.  Sussex. 
_  N.  Smithii.  —  Front  view  broadly 
linear,  sigmoid,  tnmcate,  with  conspf- 
cuous  marginal  capitate  striae  havmg 
smaller  pimcta  interposed  between  them ; 
valves  distinctlv  striate.  =:i\7tec/»a  spec- 
tahilis,  SBD.  i.  p.  39,  pi.  14.  f.  116.  Ma- 
rine. Britain.  Keel  nearly  central, 
puncta  in  fom*  rows.  Sm. 

4*  Front  vieiv  Innately  curved. 
N.  arcuata  (Greg.).  —  Front  view 
linear  arcuate,  with  roimded  ends ;  valves 
lanceolate,  obtuse;  puncta  about  20  in 
•001".  Grev.  MJ.  Y\i.  p.  82,  pi.  6.  f.  4-7. 
Maiine.     Scotland. 

5*  Frustides  straight  in  hotli  vieivs,  not 
constricted  at  the  middle. 

t  Front  -view  linear. 
N.  scalaris  (E.,  Sm.). — Large;  front 
view  broadly  linear,  with  dilated  truncate 
ends  and  broadly  sti'iated  margins,  the 
striae  alternately  longer  and  shorter; 
valves  linear  with  shortly  attenuated, 
obtuse  ends.  SBD.  i.  p.  39,  pi.  14.  f.  115. 
=  Synedra   scalaris,  EA.  p.  137,  t,  2.  2. 


782 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


f.  18.  Brackisli  water.  Europe,  Asia, 
Australia,  and  America,     (iv.  21.) 

N.  specfabilis  (E.). — Large ;  front  view 
broadly  linear,  with  truncated  cuneate 
apices ;  valves  with  rounded  ends.  = 
Synedm  spectahilis,  EA.  and  M,  several 
figures.  Europe,  Asia,  Australia,  Africa, 
and  America.  The  valves  are  figured  as 
elongated,  narrow  linear,  with  suddenly 
attenuated,  obtuse,  reflected  apices,  and 
a  row  of  puncta  on  one  margin. 

N.  insic/nis  (Greg.).  —  Front  view 
broadly  linear,  with  rounded  ends  and 
conspicuous  marginal  puncta  and  striae ; 
valves  linear  lanceolate,  straight  or 
slightly  sigmoid,  with  subcentral  keel 
and  30  distinct  striae  in  -001".  Greg. 
MT.  V.  pi.  1.  f.  46.  Marine.  Scotland. 
Distinguished  from  N.  sigmoidea  and  N. 
Brchissomi  by  its  straight  front  view; 
and  from  N.  scalaris  by  its  finer  markings, 
more  slender  form,  and  nondilated  ends. 
Greg. 

N.  gigcmtea  (E.). — Very  large,  linear, 
with  suddenly  rounded  ends ;  valves 
\\\ih.  attenuate  subacute  apices  ;  surface 
finely  striated  in  the  intervals  of  the  ^\n- 
nu[es.  =  Sgnedra  qiqantea,  ERBA.  1841, 
p.  22;  Synedra^ Lihgca,  KSA.  p.  48. 
Oasis  of  Jupiter  Amnion,  1-60". 

N.  linearis  (Ag.,  S.).  —  Front  view 
linear,  with  rounded  or  truncate  apices 
and  nearly  central  keel ;  puncta  in  a 
single  row;  striae  obscure.  SBD.  i.  p. 
39,  pi.  13  &  pi.  38.  f.  110.  =  Frustidia  line- 
aris, Ag.     Fresh  water.     Europe. 

N.  Pcdea  (K.,  S.). — Front  view  linear ; 
valves  narrow,  lanceolate,  acute.  SBD. 
ii.  p.  89.=Sy?iedra  Palea,  KB.  p.  63,  t.  4. 
f.  2 ;  Synedra  Fusidimn,  KB.  p.  64,  t.  30. 
f.  33  ;  Syiiedra  fusidioides,  Bab  D.  p.  53, 
t.  4.  f.  47.     Europe.     Frustules  minute. 

N.  tenuis  (S.).  —  Front  view  linear, 
truncate ;  valves  narrow,  lanceolate, 
acute  ;  striae  obscure.  SBD.  i,  p.  40,  pi. 
13.  f.  111.     Fresh  water.     England. 

2t  Extremities,  in  front  view,  with  a 
hyaline  wing  or  expansion  on  each  side. 

N.  spathulata  (Breb.). —  Front  view 
lanceolate,  with  the  truncate  ends  dilated 


on  each  side ;  valves  lanceolate  acute, 
with  a  single  row  of  puncta.  SBD.  i. 
p.  40,  pi.  31.  f.  268.  Marine.  France 
and  England. 

N.  distans  (Greg.). — Front  view  broad, 
sublinear,  with  distant  irregularly  dis- 
posed marginal  puncta;  apices  truncate 
with  a  slight  hvaline  expansion  on  each 
side.  GDC.  p.  58,  pi.  6.  f.  103.  Marine. 
Scotland.  Valves  lanceolate,  with  acute 
apices  and  central  keel. 

N.  hyalina  (Greg.). — Front  view  sub- 
linear,  with  small,  regular  marginal 
puncta ;  valves  narrow  linear,  with  con- 
tracted, produced  apices  and  central  keel. 
GDC.  p.  58,  pi.  6.  f.  104.  Marine.  Scot- 
land. Keel  apparently  double ;  but  per- 
haps one  is  seen  through  the  very  hyaline 
valve.    Greg. 

3  t  Front  view  lanceolate. 

N.  angidaris  (S.). — Front  view  rhom- 
boid-lanceolate, truncate ;  valves  lanceo- 
late, with  central  keel ;  puncta  in  a  single 
series  and  longitudinal  lines.  SBD.  i.  p. 
40,  pi.  13.  f.  117.  Marine.  Sussex. 
This  and  the  following  species  ought 
perhaps  to  be  placed  in  Ceratoneis. 

N.  lanceolata  (S.). — Front  view  broadly 
lanceolate,  acute  ;  valves  lanceolate,  ros- 
trate, acute,  with  eccentric  keel  and 
longitudinal  lines.  SBD.  p.  40,  pi.  14. 
f.  118.     Marine.     Sussex. 

Douhtfid  or  insufficiently  described  Species. 

N.  valens  (E.).  —  Very  large,  broadly 
linear,  finely  striated,  with  trimcate  ends. 
=  Synedra  valens,  EA.  t.  3.  2.  f.  6.  Fresh 
water,  (xii.  44.)  Mexico  and  United 
States. 

N.  curvula  (K.). —  Elongated,  curved; 
front  view  slightly  attenuated  towards 
the  truncate  apices ;  valves  acuminated, 
subacute,  sometimes  with  a  longitudinal 
punctate  line.  =  Synedra  curvula,  KB, 
p.  65,  t,  15.  f,  2.  Fresh  water.  Prussia. 
1-240". 

N.  JEhrenberc/ii  =  Synedra  amphilepta, 
EM,  pp.  34-5,  *£  11.  CapeVerd.  Elon- 
gated, straight,  linear,  with  striated  mar- 
gins and  acutely  cimeate  apices. 


Genus  CEBATOl^EIS  (Ehr.).— Frustules  as  in  Mtzschia,  but  with  long 
rostrate  ends,  and  usually  with  a  more  or  less  evident  central  pseudo-nodule. 
Professor  Smith,  after  excluding  some  of  its  species,  made  Ceratoneis  a  sec- 
tion of  Nitzschia,  and  perhaps  was  justified  in  so  doing ;  but  as  the  forms 
included  in  it  are  remarkable  for  their  fidiform  beaks,  and  there  is  some 
appearance  of  -a  central  nodule,  we  have  retained  the  genus,  at  least  for  the 
present.  Some  of  the  species  resemble  the  Closteria  in  form,  and  have  been 
referred  to  as  showing  an  affinity  between  the  Diatomaceae  and  the  Desmi- 
diea?.    The  resemblance,  however,  is  merely  superficial,  and,  instead  of  showing 


OF  THE  SURIRELLE^. 


-83 


an  affinity,  rather  proves  it  does  not  exist.  In  the  Closteria,  division  takes 
place  across  the  lunate  frond,  or  in  the  shortest  diameter,  whilst  in  this  genus 
it  occurs  in  the  opposite  direction. 

Cesatoneis  hngissima  (Breb.). — 
Valves  lanceolate,  with  very  long  sti'aight 
slender  awns,  a  subcentral  keel,  a  single 
row  of  puncta,  and  obscure  striae.  KSA. 
p.  891.  =  Kitzschia  birostmta,  SBD. 
i.  p.  42,  pi.  14.  £  119.  Marine.  France, 
Eno:land.      Front  view    straight,    with 


lanceolate    middle,    and 


long, 


linear, 


truncated  beaks,    (iv.  22.) 

C.  Closterium  (E.). — Front  view  arcu- 
ate, with  lanceolate  middle,  and  long, 
filifomi,  incurved  awns ;  valves  faintly 
striated,  with  central  keel  and  a  single 
row  of  puncta.  Ehr.  leb.  Kreidethierchen. 
t.  4.  f.  7.  =  Nitzsclda  Closterium,  SBD. 
i.  p.  42,  pi.  15.  f  120.    Europe,   (xii.  59.) 

C.  reversa  (Sm.). — Front  view  lanceo- 
late, with  loug  beaks,  the  extremities 
of  which  are  bent  in  opposite  direc- 
tions ;  puncta  obsolete ;  stiise  obscure, 
48  in  -001".  =  Nitzschia  reversa, 
SBD.  i.  p.  4.3,  pi.  15.  f.  121.  Brackish 
Avater.    Europe. 

C.  s])iralis  (K.). — Lanceolate,  with 
long,  flat,  spirallv-twisted  beaks.  KB.  p. 
104;  t.  4.  f.  38.  Marine.  Europe,  (xin.  9.) 

C.  suhulata  (Breb.).  — Lanceolate  su- 
bidate,  very  slender,  smooth,  gTadually 
tapering  into  slender  beaks,  which  are 
sometimes  straight,  sometimes  cmwed  or 
sigmoid.   KSA.  p.  89.    Marine.    France. 


C.  acicidaris  (K.). — Front  view  narrow 
linear ;  valves  lanceolate,  with  straight, 
slender  beak  ;  striae  obscure.  =  Synedra 
acicidaris,  KB.  p.  68,  t.  4.  £  3;  Nitzsclda 
acicidaris,  SBD.  p.  43,  pi.  15.  f  122.  Fresh 
water.     Em'ope. 

C.  gracilis  (Breb.). — Elongated,  very 
slender,  linear,  with  rather  obtuse 
straight,  cmwed,  or  sigmoid  beaks ;  striae 
obscure.  KSA.  p.  89.  =  Nitzsclda  T(Bnia, 
SBD.  p.  43,  pi.  15.  f.  123.  Fresh  or  brack- 
ish water.     Em-ope. 

Douhtfid  Species. 

C.  CretcB  (E.).  —  Smooth,  na\dcular, 
very  slightly  constricted  at  the  middle, 
wdth  acute,  sti*aight,  not  much  produced 
apices.  ERBA.  1844 ;  Microg.  pi.  22. 
£  61.  Fossil.  Sicily.  The  figure  shows 
a  distinct  median  line  and  nodule. 

C.  knninaris  (E.). — Broadly  lanceolate, 
with  striated  margins  and  short  rostrate 
apices.  EA.  t.  3.  7.  £  24.  Asia  and 
America.  A'alve  with  median  line  and 
centi-al  nodide. 

C.  Linea.  =  Synedra  Linea,  EM.  pi.  18. 
£  78.  Fossil.  Virginia.  Lanceolate,  with 
punctated  margins,  and  naiTow-linear, 
rostrate  ends. 

C.  rhomhoides  (E.). — India. 


Genus  AMPHIPLEURA  (Kiitz.). — Fnistnles  simple,  elongated;  valves 
with  longitudinal  ridges.  An  iU-defined  genus,  the  species  of  which  differ 
considerably  in  their  appearance. 

straight:  valves  slightly  sigmoid.  KB. 
p.  104,  t.  4.£  30.  =  Ainphipleura  sigmoidea, 
SBD.  i.  p.  45,  pi.  15.  £  128.  Marine. 
Europe,  (xiii.  2.)  It  forms  brown 
stain-like  patches  on  marine  rocks,  and 
scarcely  changes  colom-  when  gathered. 

A.  infiexa  (Breb.). — Valves  linear.  In- 
nately curved,  slightly  attenuated,  some- 
what constricted  beneath  the  rounded 
apices.  KSA.  p.  88.  Marine,  (iv.  31.) 
France  and  Britain.  1-430"  to  1-336". 
Striae  close,  usually  very  indistinct.  In 
mode  of  growth  and  colour  it  resembles 
A.  rigida,  but  changes  to  a  green  coloiu" 
as  soon  as  gathered. 


Amphipleura  pellucida  (K.). — Frus- 
tules  slender,  hyaline  ;  valves  narrow 
lanceolate,  with  rather  obtuse  apices. 
KB.  p.  103,  t.  3.  £  32 :  SBD.  pi.  15.  £  127. 
=  Naiicida  pellucida,  Ehr  In£  t.  13; 
Aulacocystis  jjellucida,  Hass  Algae,  p.  427, 
pi.  102.  £  8.  Fresh  water.  Europe. 
(IV.  30,  IX.  140  &  xm.  1.)  1-300"  to 
1-140".  Frustides  often  connected  in 
flat,  longitudinal  band-like  series  by  a 
mucous  covering. 

A.  Dauica  (K.). — Lanceolate,  obtuse 
or  truncated,  smooth.  KB.  p.  10-3,  t.  30. 
£  38.     Marine.     Em-ope.     1-390". 

A.  7'igida  (K.).  —  Elongated,  linear 
lanceolate,  \\itli  truncate  ends:  front  view 


FAMILY  Y.— SUEIEELLE^. 

Fnistnles  prismatic  or  subdisciform  ;  striae  of  the  lateral  surfaces  either 
interrupted  by  a  longitudinal  line  or  radiate.     The  SuriiTlleae  comprise  by  no 


784  SYSTEMATIC  HISTORY  OF  THE  rNTrSORIA. 

means  a  satisfactory  group,  and  we  Believe  that  Sjiiedi-a  and  the  other  genera 
Avith  wand-like  frustiiles  should  be  removed  from  this  family,  whether  they 
be  united  to  the  Fragilarieae  or  retained  together  as  a  distinct  family ;  but  the 
object  of  tliis  work  is  rather  to  present  an  ej^itome  of  what  has  already  been 
done  than  to  introduce  any  extensive  alterations.  "  The  genus  Campylo- 
disciis  is  near  to  the  ]Melosii^ea3,  but  the  disk  is  not  circular  but  elliptical. 
Siuii'ella  and  the  free  frustiiles  of  Sjmedra  are  related  to  the  K'aviculese,  but 
they  want  the  middle  clearly- defined  nodule  in  the  secondary  sides.  Bacil- 
laria  is  closely  allied  to  the  Fragilariea),  especially  to  Diatoma  ;  but  the  striae 
of  the  friistule  are  interrupted  in  the  middle,  while  in  Diatoma  they  are 

pervious Comparing  together  the  genera  Campylodiscus,  tSurii'ella,  Bacil- 

laria,  Synedra,  it  is  easily  perceived  that  the  last  two  only  deviate  from  the 
Fragilarieae  by  the  character  of  interrupted  strise  ;  and  the  first  two,  deviating 
sensibly  in  the  succession  of  species  from  the  cii^cular  shape  of  the  lateral 
sinfaces,  or  of  the  transverse  section,  establish  a  transition  between  the 
Melosii^ese,  and  the  group  formed  of  these  two  genera,  along  with  the  Fra- 
gilarieae and  the  Meridiete.  Hence  it  is  impossible  to  establish  an  organo- 
graphieal  character  that  shall  embrace  the  entire  family  and  strictly  represent 
its  type."   (Meneg.) 

Genus  BACILLARIA  (Gmel.). — Frustules  linear,  straight,  united  into  a 
short  band,  moving  on  each  other  by  a  sliding  motion  without  separation ; 
valves  haA-ing  a  longitudinal  punctated  keel.  The  elongated  wand-like  fms- 
tiiles  distinguish  this  from  all  other  genera,  except  some  species  of  Diatoma 
and  Synedi-a.  It  differs  from  the  former  by  the  frustules  not  forming  zigzag 
chains,  and  from  the  latter  by  its  band-hke  filaments.  "  The  principal  organo- 
graphical  character  that  distinguishes  Bacillaria  from  the  Fragilarieae  is  the 
same  that  allies  it  to  a  different  group  of  the  family,  viz.  the  interruption  of 
the  transverse  striae  in  the  median  hue  of  the  secondary  siufaces,  to  which  is 
added  the  parallelism  of  the  primary  siufaces."  (Menegh.) 

*  Frustules  united  into  a  short  hand         l^te,  hvaline  ;  striae  obsolete.      "" 

Bacillaria  paracloxa  (Gmel.).  — 
Valves  linear  lanceolate,  E  Inf.  p.  195 ; 
SBD.  pi.  32.  f.  279.  Ditches  in  salt 
marshes.  Em-ope.  (iv.  18 ;  ix.  166, 
167.) 

2  *  Frustules  bundled. 

B.  cursoria  (Donkin). — Valves  lanceo- 


TMS.  vi.  p.  16,   pi.  3.   f.  12.      Marine. 
England,    (iv.  19.) 

B.  socialis  (Greg.). — Valves  lanceolate, 
with  fine,  but  distinct,  transverse  striaD. 
=  Nitzschia  socialis,  Greg.  TMS.  v.  p.  8, 
pi.  1.  f.  45.  Marine.  Scotland.  Frustules 
in  groups,  striae  30  to  36  in  -001.  Greg. 


Genus  HOMCEOCLADIA  (Ag.).  —  Frustules  bacillar,  Nitzschoid,  within 
subular,  siibmembranaceous,  branched  filaments.  Thj  frustules  are  usually 
fasciculated ;  and  their  structure,  which  is  that  of  the  genus  Mtzschia,  sepa- 
rates the  present  from  the  other  frondose  genera  (Sm.).  When  dried,  the 
filaments  become  opake,  and  usually  acquire  a  metallic  lustre. 

HoMCEOCLADiA  Murtiana  (Ag.). —  H.  Ancjlica  (Ps.^.). — Frond  trichoto- 
Frond  umbellately  branched,  membrana-  moiis  below,  dichotomoiis  above,  opake 
ceous,  rugose,  opake  when  dried;  frustules  when  dry,  scarcely  rugose ;  frustules  very 
crowded,  linear,  elono-ated,  obtuse.  Ag.  long,  linear,  obtuse.  Ag  CD.  p.  25 ;  KB. 
CD.  p.  25 ;  KB.  p.  110,  t.  30.  f  83.  =^.  j  t.  30.  f.  82.  France  and  England.  Does 
Anglica,  Ptalfs,  Annals,  xvi.  pi.  3.  f  1.  i  not  adhere  to  paper.  We  are  unable  to 
Marine.  Europe,  (iv.  2,3;  xi v.  47-49.)  determine  from  the  fragments  we  have 
Fronds  much  branched,  flaccid  when  re-  {  examined  whether  this  is  truly  distinct 
cent,  and  of  a  dark  olive-colour,  -^dth  a  '  from  H.  3Iartiana. 
metallic  lustre  and  transversely  wi-inkled  H.  Arhuscula  (K.).— Very  much  and 
when  dried.  umbellately  branched,   upper    branches 


OF  THE  SURIRELLE^. 


785 


fascicular,  capillary,  spuriously  jointed; 
frustules  linear,  elong-ated,  obtuse, 
smooth.  KB.  p.  Ill,  t.  22.  f.  11.  Ma- 
rine.    Venice.     1-7". 

H.  dilatata  (K.). — Much  branched,  se- 
taceous, branches  fastigiate,  incrassated 
aboTe,  clavate ;  fasciculi  closely  conti- 
guous ;  frustules  linear,  elongated,  acicu- 
lar,  obtuse.  KB.  p.  Ill,  t.  23.  f.  1.  Ma- 
rine.    Adriatic.     1-12". 

H.  moniliformis   (Kiitz.). — Capillary  ;  | 
branches  slender,  elongated,  moniliform ;  j 
fasciculi  of  frustules  remote ;   frustules  I 
very  long  linear,  obtuse.     KB.  p.  110, 
t.  22.  f.  10.    Adriatic,    (xiv.  45, 46.) 

H.  pumila  (Ag.,  K.). — Ii-regularly  di- 
vided into  equal,  obsoletely-articulated, 
capillary  branches ;  frustules  short  linear, 
with  rounded  ends.  KB.  p.  110,  t.  22. 
f  9.  =  Schizonema  pumilum,  Ag  CD.  p.  16. 
Adriatic,     (xiv.  37, 38.) 

H.  penicillata  (Kiitz.).  —  Fastigiately 
branched  ;    branches    divaricate,    fasti- 


giately di\ided;  terminal  ramuli  white, 
in  pencils;  primary  tube  thick,  gelati- 
nous cartilaginous ;  frustules  densely  ag- 
gregated, slender,  linear  acicular,  very 
naiTow.     KSA.  p.  97.     France.  • 

H.  luhrica  (Me.,  K.).  —  Gelatinous, 
green,  setaceous,  for  the  most  part  di- 
\-ided  at  the  apex;  fmstules  fascicu- 
late, densely  aggregated,  linear.  KSA. 
p.  98.  =  Schizonema  luhriciwi,  Menegh. 
Adriatic. 

_  ll.Jiliformis  (S.). — Frond  simple;  fas- 
cicles of  3  or  4  frustules ;  front  view 
linear-lanceolate,  obtuse;  valves  linear 
lanceolate,  subacute.  SBL).  ii.  p.  80,  pi. 
55.  f.  348.  Brackish  and  fresh  water. 
England,    (rv.  25.) 

H.  sigmoidea  (S.). — Frond  simple; 
frustules  irregularly  fasciculated  in  bun- 
dles of  about  6 ;  front  view  sigmoid ; 
valves  linear,  with  attenuated  ends.  SBD. 
ii.  p.  81,  pi.  55.  f.  349.  Brackish  water. 
Britain,    (iv,  26.) 


Genus  SYNEDEA  (Ehr.). — Frustules  elongated,  wand-like,  attached  by 
the  lower  end,  lateral  surfaces  equal  to  or  less  than  the  front  view,  traversed 
by  a  smooth  median  longitudinal  line.  The  true  species  of  Synedi^a  are 
distinguished  from  all  other  genera  by  their  wand-like  form  and  attachment 
by  one  end.  They  are  usually  either  fasciculated  or  fixed  to  a  distinct  stipes 
in  a  fan-like  manner.  "  As  to  the  organographical  considerations  which  can 
be  instituted  in  this  genus,  they  reduce  themselves  to  the  single  one  of  length 
predominating  over  breadth  and  the  eminently  bacillary  foim  derived  from  it. 
Thus  Kiitzing  observed  of  the  opposite  characters  of  Synedra  and  SurireUa, 
that  the  lateral  surfaces  exceeded  in  one  the  primary  surfaces  in  the  other." 
Several  of  the  species  at  present  placed  in  this  genus  may  prove,  when  better 
known,  to  belong  to  Nitzschia. 


*  Minute ;  attachment  slight ;  strice 
indistinct  or  obsolete. 

Synedra  quadrangula  (K.).  —  Very 
minute,  in  one  view  narrowly  linear,  in 
the  other  broad  quadrangidar.  KB.  p. 
63,  t.  3.  f.  23.     Marine.     Norway. 

S.Atomus  (K.,  Nao). — Very  minute,  in 
one  view  elliptic  with  rounded  apices, 
in  the  other  linear  truncate.  KSA.  p. 
^0.  =  Amphora  Atomus,  KB.  t.  30.  f.  70; 
Synedra  minutissima,  /3  pelliculosa,  K. 
(according  to  M.  de  Brebisson).  Fresh 
water.     Europe. 

_  S.perptmlla  (K.). — Veryminute;  front 
view  very  nan-ow  linear ;  valves  lanceo- 
late, contracted  near  the  obtuse  apices. 
KB.  p.  63,  t.  3.  f.  31.     Venice. 

S.  Biasolettiana  (K.). — Very  minute ; 
front  view  very  narrow  linear,  arcuate ; 
valves  lanceolate,  obtuse.  KB.  p.  63,  t. 
3.  £  22.    Fresh  water.    Trieste. 

S.  pmilla  (K.).— Minute ;  front  view 


broadly  linear ;  valves  oblong-elliptic, 
with  somewhat  rounded  apices.  KB. 
p.  63,  t.  3.  f.  29.     Carlsbad.     1-1800". 

S.  angustata  (K.).  Front  view  very 
narrow  linear;  valves  broader,  oblong, 
with  attenuated,  rather  obtuse  apices. 
1^.  p.  64,  t.  4.  f.  1,  3.  Hot  springs. 
Italy.     1-720".  ° 

S.  virginalis  (K.). — Front  view  linear, 
truncate,  with  attenuated  centre ;  valves 
lanceolate.  KB.  p.  64,  t.  3.  f.  15.  Genoa. 
1-600". 

S.  ventricosa  (Rab.). — Front  view  nar- 
row linear;  valves  ventricose,  with  short, 
produced,  beak-like  apices.  Rab  D.  p.  52, 
t.  4.  f.  36.     Apennines. 

2  *  Frustules  in  lateral  view  arcuate. 

S.  lunaris  (E.). — Valves  narrow,  linear, 
arcuate,  slightly  attenuated,  obtuse; 
striae  famt,  36  in  -001".  EI.  t.  17  f  4  • 
SBD.  i.  p.  69,  pi.  11.  f.  82.  Fresh  water! 
Common.  Europe,  Asia,  and  America 
3e 


786 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


(x.  185.)    Frustiiles  affixed,  often  aggre- 
gated. 

S.  falccda  (K.) . — ^\^aly  es  arcuate,  linear, 
with  obtuse  apices,  faint  stripe,  imdulated 
Tenter.     KSA.  p.  43,     Paris. 

S.  Ulunaris  (E.).  —  Valves  linear, 
curved,  biliinate,  obtuse,  attached,  more 
attenuated  at  base  ;  stride  obsciu-e.  EI. 
1. 17.  f.  5.  Freshwater.  Europe.  Valves 
bent  inwards  at  the  middle,  so  as  to  be- 
come bilunate. 

S.  longissima  (Sm.).— Valve  much  elon- 
gated, slightly  and  gradually  attenuated, 
with  capitate  apices  ;  strise  28  in  -001". 
SBD.  i.  p.  72,  pi.  12.  f.  95.  Botanic  Gar- 
den, Belfast.  Is  this  distinct  from  S. 
biceps  ? 

S.  UcepsiK.). — Much  elongated;  valves 
very  slender,  gradually  attenuated,  with 
capitate  apices  and  distinct  transverse 
strife.  IvB.  p.  m,  t.  14.  f.  18.  Fresh 
water.  Europe.  1-100"  to  1-60".  Front 
view  linear,  with  striated  margins,  some- 
times dilated  at  the  ends. 

S.  alpina  (Nag.).  —  Slender,  faintly 
striated  ;  front  view  straight,  linear ; 
valves  arcuate,  very  nan-ow  lanceolate, 
with  produced  capitate  apices.  KSA. 
p.  43.  Switzerland.  1-600"  to  1-336". 
S.  suharcuata  (Nag.).— Small ;  front 
view  straight,  linear,  valves  slightl}^  ar- 
cuate, with  produced  capitate  apices. 
1-2400"  to  1-1200".  Switzerland.  Like 
S.  alpina,  but  only  half  the  size.    Rab. 

S.JlexHosa  (Breb.).— Front  view  broadly 
linear;  valves  linear,  cm'ved,  sometimes 
flexuose,  wdth  capitate  apices  and  very 
fine  transverse  stride.  =  J^unofia  Jlexuosa, 
KSA.  p.  6 ;  &  hicejjs,  SBD.  i.  pi.  11.  f.  83. 
Fresh  water.  France,  England.  /3,  valves 
two  or  three  times  flexed.  Differs  from 
S.  biceps  in  having  linear,  not  tapering 
valves. 

S.  pachyceph ala  (K. ) .  —  Front  _  view 
slender,  linear  ;  valves  linear,  slio-htly 
arcuate,  with  cla^iform  apices  and  indi- 
stinct striee.  =  Eunotia  pachycephala, 
KSA.  p.  6.     Fresh  water.     Europe. 

S.  arcuata  (Nag.).  —  Smooth;  front 
view  straight,  linear,  with  truncate  ends; 
valves  linear,  arcuate,  with  rounded 
apices.     KSA.  p.  890.     Switzerland. 

S.  f/ibbosa  (R.).— Front  view  linear; 
valves  arcuate,  tapering  to  the  slightly 
constricted  recurved  apices  ;  venter  con- 
cave, gibbous  at  the  middle.  =  Navicula 
Arcus,  EL  p.  182 ;  CymbeUa  Arcus,  HBA. 
p.  429 ;  Ceratoneis  ^ Arcus,  KB.  p.  104, 
t.  6.  f.  10 ;  Eunotia  Arcus,  SBD.  i.  p.  15, 
pi.  2.  f.  15.  Fresh  water.  Europe.  The 
frustules  are  affixed,  as  in  other  species 
of  Synedra. 


S.  hamata  (S.).  —  Valves  linear  or 
linear-lanceolate,  ^v-ith  suddenly  con- 
stricted, produced,  incurved  apices ;  striae 
marginal,  30  in  -001".  SBD.  i.  p.  73,  pi. 
30.  f.  264.     Fresh  water.     Sussex. 

3  *    Valves  straight,  with  a  circular,  defi- 
nite  central  pseudo-nodule. 

S.  pidcheUa  (Ralfs,  Kiitz.). — Frustules 
in  fan-shaped  clusters  on  a  compressed- 
dichotomous  stipes ;  valves  lanceolate, 
obtuse,  with  a  median  umbilicus.  KB. 
p.  68,  t.  29.  f.  87;  SBD.  i.  p.  70,  f.  84.= 
Ctenophora  pulcheUa,  Breb.,  Si/nedra 
Vertebra,  Greg.  M J.  iii.  pi.  4.  f.  22.  Ponds 
and  slow  streams.  England  and  France. 
Strife  33  in  -001",  Sm.  ( JV  7^) 

S.  mimdissima  (K.). — Very  minute  ; 
front  view  narrow  linear ;  valves  lanceo- 
late, rather  obtuse;  striae  36  in  -001". 
KB.  p.  63,  t.  3.  f.  30;  SBD.  pi.  11.  f.  87. 
Fresh  water.     Europe. 

S.  gracilis  (K.)-  —  Frustules  affixed, 
scattered  ;  valves  lanceolate,  acute,  with 
a  median  pseudo-nodule.  KB.  p.  64, 1. 15. 
f.  8  :  SBD.  i.  p.  70,  pi.  11.  f.  85.  Marine. 
Europe.     Striae  obscure,  39  in  -001",  Sm. 

S.  Smithii  (R.). — Frustules  in'egularly 
affixed;  valves  lanceolate,  acute,  with 
36  very  faint  striae  in  '001."  =  Synedra 
acicularis,  SBD.  i.  p.  70,  pi.  11.  f.  86. 
Brackish  water.     England. 

4  *   Valves  with  very  long  aivn-like  beaks 

(Toxarium)  ;  nodule  obsolete. 

S.  undidata  (Bailey). — Valves  slender, 
lanceolate  at  the  middle,  tapering  into 
very  long,  linear,  undidated  awns,  with 
clavate  apices.  SBD.  ii.  p.  97 ;  Greg.DC. 
p.  59,  pi.  6.  f.  107.  =  Toxarium  undidatum, 
Bailey,  MO.  p.  15,  figs.  24,  25.  Marine. 
America  and  Europe.  Front  view  linear, 
broader ;  valves  arcuate  or  straight,  wath 
24  moniliform  striae  in  -001". 

S.  Hennedyana  (Greg.). — Frustules  as 
in  S.  undulata,  but  the  awns  not  undu- 
late. GDC.  p.  60,  pi.  6.  f.  108.  Marine. 
Scotland.   . 

5  *  Frustules  affixed,  aggregated  or  scat- 

tered;   pfseudo-nodule    obscure    or  in- 
definite. 

S.  parvula  (K.). — Front  view  linear, 
truncate  ;  valves  broad  lanceolate,  acute. 
KB.  p.  64,  t.  30.  f.32.  Fresh  water.  Ger- 
many and  France.  1-1200".  Sometimes 
free,  sometimes  attached  and  densely 
aggi'egated  in  a  radiant  manner. 

S.  subtilis  (K.).  —  Slender,  radiant; 
valves  narrow  linear-lanceolate,  very 
acute.     KB.  p.  64, 1. 14.  f.  2  a.  =  Navicula 


OF  THE  SUEIRELLE^. 


Acus,  E  Inf.  p.  176, 1. 13.  f.  4.     (ix.  147.) 
Germany  and  France. 

S.  dissipata  (K.).  —  Slender,  affixed, 
radiant ;  front  view  narrow  linear,  trun- 
cate- valves  narrow  lanceolate,  acute. 
KB.  p.  64,  t.  14,  f.  3.  =  *S'.  fasciculata, 
EI.  t.  17.  f  3.  Fresh  water.  Europe, 
Australia,  and  Asia. 

S.famelica  (K.). — Delicate, irreo-ularly 
aggregated,  very  narrow  linear,  truncate 
in  lateral  view,  front  view  rather  acute. 
KB.  p.  64,  t.  14.  f.  8.  1.  Fresh  water. 
Gennany.  Is  a  somewhat  larger  form  of 
S.  dissipata,  Rab. 

S.  radians  (K,).  — Delicate,  densely 
aggregated,  radiant ;  front  view  very  nar- 
row linear,  truncate ;  valves  narrow  lan- 
ceolate, rather  obtuse.  103.  p.  64,  t.  14. 
f  7.  Europe.  1-600".   A  minute  species. 

S.  tenuissima  (K.). — Very  slender, 
elongated  J  front  view  exactly  linear, 
truncate ;  valves  acicular,  acute.  KB. 
p.  64,  t.  14.  f.  6.  Stagnant  waters. 
Germany  and  France.     1-180". 

S.  tenuis  (K.). — Slender,  elongated; 
front  view  exactly  linear,  truncate ; 
valves  narrow  lanceolate,  with  some- 
what obtuse  apices.  KB.  p.  65,  t.  14. 
f.  12.  Fresh  water.  Germany  and 
France.     1-168". 

S.  Acuta  (K.).  —  Slender,  elongated, 
lanceolate,  in  front  \dew  truncate,  in 
lateral  view  very  acute.  KB.  p.  65,  1. 14. 
f  20.  Fresh  water.  Dalmatia  and 
France.     1-72". 

S.  IcBvis  (E.). — Slightly  and  irregularly 
affixed  ;  front  view  slightly  attenuated, 
truncate;  valves  more  attenuated,  ob- 
tuse. EA.  t.  2.  6.  f  2.  Marme.  Em-ope 
and  America.     1-130". 

S.  gracillima  (Rab.). — Front  view 
elongated,  very  narrow  linear ;  valves 
linear,  acicular,  acute.  Rab  D.  p.  53, 
t.  4.  £  20  d,  e.     Dresden. 

S.  satina  (S.).  —  Valves  lanceolate, 
gi-aduaUy  tapering  towards  the  somewliat 
obtuse  apices  ;  striae  distinct,  32  in  -001". 
SBD.  i.  p.  71,  pi.  11.  f  88.  Marine. 
England. 

S.  apiculata  (Rab.). — Very  slender  ; 
valves  linear,  acicular,  with  shortly 
tapering  apices,  faintly  striated.  Rab  D. 
p.  56,  t.  5.  f  20  a,  b,  c.     Dresden. 

S.  amphicepliala  (K.). — Slender ;  front 
view  linear,  truncate ;  valves  narrow 
lanceolate,  tapering,  with  capitate  apices. 
KB.  p.  64,  t.  3.  f.  12.  Fresh -water. 
Germany.     1-360". 

^.fontinalis  (S.). — Frustules  scattered ; 
valves  linear-lanceolate  or  elliptic-lan- 
ceolate, with  produced,  subcapitate 
apices;   nodule  indefinite;  striae  27   in 


•001",  Sm  ANH.  1857,  p.  9,  pi.  1.  £  9. 
Fresh  water.     Pyi-enees. 

S.  gi1)l>a  (E.).— Smooth,  fasciculated, 
elongated,  narrow  linear;  valves  broadly 
tumid  at  the  middle,  with  gradually 
attenuated,  obtuse  apices.  EA.  p.  137. 
United  States. 

S.  delicatissima  (S.). — Valves  elon- 
gated, very  narrow,  gradually  tapering 
to  the  subacute  apices ;  striae  27  in  -001  . 
SBD.  i.  p.  72,  pi.  12.  f.  94.  Pseudo-nodule 
indefinite. 

S.  tenera  (S.).  —  Frustules  clustered  ; 
valve  nearly  linear  or  attenuated  towards 
the  slightly  inflated  apices ;  nodule  inde- 
finite ;  striae  60  in  -001".  SBD.  ii.  p.  98. 
Fresh  water.  Britain.  In  outline  not 
unlike  S.  delicatissima,  but  far  smaller 
and  with  more  delicate  striae,  Sm. 

S.  lanceolata  (K.). — Front  view  nar- 
row linear,  with  slightly  dilated  apices ; 
valves  lanceolate,  distinctly  striated,  with 
a  blank,  rhomboid  median  space.  KB. 
p.  66,  t.  30.  £  31.  America.  1-600"  to 
1-310". 

_S.  dehilis  (K.). — Minute;  front  \dew 
slightly  attenuated,  truncate,  with  obso- 
letely  striated  margins;  valves  lanceo- 
late, with  produced  apices.  KB.  p.  65, 
t.  3.  £  45.  =  *S'.  porrecta,  Rab  D.  p.  65, 
pi.  4.  £  27.  Stagnant  waters.  Em^ope, 
common. 

_S.  mesolepta  (K.). —Delicate ;  front 
view  dilated  at  the  ends ;  valves  lan- 
ceolate, curved  or  slightly  sigmoid. 
KB.  p.  66,  t.  30.  £  30.  America. 
1-160". 

S.  notata  (K.). — Small,  with  obsoletely 
striated  margins;  front  \'iew  quadran- 
gular; valves  eUiptic-oblong,  with  ob- 
tuse ends.  KB.  p.  65,  t.  3.  £  33.  Stag- 
nant waters.     Em-ope.     1-650". 

S.  3Iartensiana  (K.).  —  Small,  di- 
stinctly striated ;  front  view  linear,  trun- 
cate; valves  rather  broader,  lanceolate, 
subacute.  KB.  p.  65,  t.  3.  £  9.  Marine. 
Europe. 

_S.  VaucliericB  (K.). — Minute;  front 
view  linear,  truncate;  valves  linear- 
lanceolate  with  somewhat  produced 
ends,  indefinite  pseudo-nodule,  and  30 
marginal  striae  in  -001".  KB.  p.  65, 
t.  14.  £  4;  SBD.  i.  p.  73,  pi.  11.  £  99. 
Fresh  water,  especially  on  species  of 
Vaucheria.     Em-ope. 

S.  cequalis  (K.),  —  Front  view  dilated 
at  the  ends  ;  valves  linear,  with  rounded 
apices,  indefinite  pseudo-nodule,  and  24 
striae  in  -001".  KB.  p.  m,  t.  14.  £  14.  = 
aS'.  obtusa,  SBD.  i.  p.  71,  pi.  11.  £  92. 
Stagnant  waters.     Europe.     1-140". 

S.    ini'.cstiens    (S.).  —  Valves    linear, 
3e2 


788 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


slightly  attenuated  towards  the  rounded 
apices,  nodule  obsolete;  striae  26  in 
•001".  SBI).  ii.  p.  98.  Marine.  Scot- 
land. 

S.  acuta  (E.). — Front  view  exactly 
linear,  truncate ;  valves  linear,  stiiated, 
suddenly  acuminated  near  the  apices. 
EA.  1. 1.  2.  f.  22.  America,  Asia,  Au- 
stralia, and  Africa.     1-144". 

S.  Oxijrhynclms  (K.).  —  Front  view 
linear ;  valves  linear,  narrower,  suddenly 
contracted  into  a  beak  at  the  ends.  KB. 
p.  66,  t.  14.  f.  9-11.  Gei-many.  Di- 
stinguished fi'om  S.  acuta  by  its  con- 
stricted ends. 

S.  vitrea  (K.). — Front  view  vdih  di- 
lated apices ;  valves  linear,  wath  sud- 
denly attenuated,  obtuse  ends.  KB. 
p.  66,  t.  14.  f.  17.  France.  Distin- 
guished from  aS'.  Oxyrhynchus  only  by  its 
dilated  ends  in  the  fi'ont  view,  Kab. 

S.  amphirhynclms  (E.). — Large  ;  front 
view  linear,  not  dilated  at  the  ends; 
valves  contracted  into  obtuse  beaks. 
EA.  t.  3.  1.  f.  25.  Fresh  water.  Eu- 
rope, Africa,  and  America.  1-120"  to 
1-96".    No  large,  median,  smooth  space. 

S.  prcemorsa  (E.). — Frontviewbroadly 
linear,  with  truncated,  cmieate  apices ; 
valves  linear,  with  roimded  cuneate  ends. 
EA.  t.  3.  6.  f.  11.     Mexico. 

S.  defonms  (S.). — Valves  linear  or 
linear-elliptical,  suddenly  consti'icted 
towards  the  produced  and  often  distorted 
extremities;  nodule  obsolete;  striae  36 
in  -001".  SBD.  ii.  p.  98.  Fresh  water. 
Sussex. 

S.  JJlna  (E.). — Front  view  exactly 
linear ;  valves  linear,  slightly  attenuated 
near  the  obtuse  apices.  E  Inf.  t.  17.  f.  1 ; 
SBD.  i.  p.  71,  pi.  11.  f.  90.  Fresh  water. 
Europe,  Asia,  Australia,  Africa,  and 
America,  (x.  184.)  1-280"  to  1-100". 
Striai  24  in  -001",  Sm. 

S.  splendens  (K.). — Large,  elongated; 
front  \'iew  with  dilated  truncate  ends ; 
valves  lanceolate,  obtuse.  KB.  p.  QQ, 
t.  14.  f.  16.  =  6'.  radians,  SBD.  i.  p.  71, 
in  part.  Fresh  water.  Europe,  Asia, 
and  Africa.  1-72".  Differs  from  S. 
Ulna  merely  in  its  dilated  apices,  Rab. 

S.  Banica  (K.). — Slender ;  front  view 
with  dilated,  truncate  ends  ;  valves  lan- 
ceolate with  slightly  clavate  apices. 
KB.  p.  66,  t.  14.  f.  13.  Stagnant  waters. 
Europe.  1-140".  Is  only  a  more  slen- 
der form  of  >S',  sple?ide)is,  Rab. 

S.  mesocampa  (Breb.). — Size  and  form 
of  S.  TJlna,  but  in  the  lateral  view  Hexed 
at  the  middle.     KSA.  p.  44.     France. 

S.  capitata  (E.). — Valves  linear,  with 
the  extremities  dilated  into  a  triangular 


head;  striae  23  in  -001".  E  Inf.  t.  21. 
f.  28 ;  SBD.  i.  p.  72,  pi.  12.  f.  93.  Fresh 
water.  Em-ope,  Asia,  Africa,  and  Ame- 
rica. (lY.  29;  X.  185.)  Very  large;  length 
1-120"  to  1-40". 

S.  longicejjs  (E.). — Very  large,  in  form 
approaching  very  near  to'^iS'.  cajntata,  but 
wath  styliform,  produced  apices.  ERBA. 
1845.  Fresh  water.  America.  1-12" 
to  1-144". 

6  *  Frusttdes  attachedhy  a  distinct,  mostly 
persistent,  stipes ;  pseudo-nodule  obsolete 
or  indefinite. 

t  Frustules  in  fan-shaped  clusters  on  a 
short,  mostly  simple,  stipes. 

S.  Acus  (Kiitz.). — Slender,  smooth; 
front  view  slightl}'  attenuated,  truncate ; 
valves  very  narrow  lanceolate,  acicular. 
KB.  p.  68, 1. 15.  f.  7.  Hamburgh.  1-960". 

S.fatniliaris  (K.). — Smooth,  distinctly 
tabeilate  and  flabellately  disrupted ; 
front  view  slightly  attenuated  near  the 
trimcate  ends ;  valves  lanceolate,  acute. 
KB.  p.  68,  t.  15.  f.  12.     France.     1-320". 

S.  parva  (K.). — Minute,  smooth,  nar- 
row linear,  truncate  ;  valves  narrow  lan- 
ceolate. KB.  p.  67,  t.  15.  f.  9.  Marine. 
Italy.     1-960". 

S.  socialis  (Rab.). — Front  view  linear, 
with  truncated,  cuneate  ends;  valves 
lanceolate,  distinctly  striated.  Rab  D. 
p.  56,  t.  4.  f.  22.     Fresh  water.     Italy. 

S.  Gallionii  (E.). — Frustules  large,  on 
a  thick,  convex  stipes ;  valves  lanceo- 
late; striae  36  in  -001",  interrupted  by  a 
median  line.  E  Inf.  t.  17.  f.  2 ;  SBD. 
i.  p.  74,  pi.  30.  f.  265.  Marine.  Em-ope, 
Asia,  Africa,  and  America,  (xn.  34, 36.) 
1-120"  to  1-100". 

S.  fasciculata  (Ag.,  K.). — Frustules  ta- 
bulate, on  a  thick,  hemispherical  stipes ; 
front  view  linear,  wdth  subattenuate, 
truncate  apices ;  valves  lanceolate.  KB. 
p.  68,  t.  15.  f.  6.=Diato7na  fasciculatmn, 
Ag  CD.  p.  51 .     Marine.     Common. 

S.tabulata  (Ag.,  K.). — Frustules  large, 
on  a  thick,  abbreviated  stipes;  front 
view  broadly  linear,  ti-uncate ;  valves 
lanceolate,  with  subcapitate  apices ;  striae 
marginal,  27  in  -001".  KB.  p.  68,  t.  15. 
f.  10 ;  SBD.  pi.  12.  f.  96.  =  Diatoma 
tahulatmn,  Ag  CD.  p.  50.  Marine. 
Europe. 

S.  affinis  (K.). — Frustules  subtabulate, 
on  a  hemispherical  stipes;  front  view 
slender,  linear,  with  subattenuate  trun- 
cate apices;  valves  lanceolate,  acute, 
with  32  marginal  striae  in  -001".  KB. 
p.  68,  t.  15.  f.  6,  11 ;  SBD.  i.  p.  73. 
Marine.      Em-ope.      1-320".      FrustiUes 


OF  THE  SUEIEELLE^. 


789 


united  in  flabellate  or  radiating  bundles, 
Sm. 

S.  barbatula  (K.). — Minute,  tabulate ; 
£i*ont  view  linear,  truncate,  watli  a  ter- 
minal mucous  appendage ;  valves  elliptic- 
lanceolate.  KJB.  p.  68,  t.  15.  f.  10.  4. 
Marine.     Eui'ope.     1-9G0". 

S.  truncata  (Grev.). — Frustules  united 
in  tablets,  obscm-ely  stipitate ;  front 
view  linear,  trimcate ;  valves  lanceolate, 
obtuse.  =Z>iW,07«a  and  Exilaria  truncata, 
Grev. ;  Exilaria  fasciculata,  Hass.  ; 
Synedra  fasciculata,  SBD.  i.  p.  73,  pi.  11. 
f.  100.  Fresh  water.  Europe.  Striae 
40  in  -001",  Sm. 

S.  Areas  (K.). — Frustides  flabellate, 
attached  to  a  cushion-like  stipes ;  front 
view  curved ;  valves  lanceolate,  with  30 
marginal  striae  in  -001.  KB.  p.  68,  t.  30. 
f.  50 ;  SBD.  i.  p.  73,  f.  98.  (iv.  27.) 
Marine.    Europe  and  America. 

2 1  Frustules  on  an  elongated,  often 
branched,  stipes. 

S.  Ehrenhergii  (K.). — Frustules  at- 
tenuated near  the  obtuse  apices,  teiminal 
on  a  long,  linear  stipes.  KB.  p.  69, 1. 11. 
f.  6.     Fresh  water.     Berlin. 

S.  Saxonica  (K.). — Stipes  a  little  elon- 
gated; frustules  slender;  front  view 
linear,  trimcate ;  valves  narrow  lanceo- 
late. KB.  p.  68,  t.  15.  f.  14.  Salt  Lake 
at  Mansfeld.     1-330". 

S.fulffens  (Grev.,  S.). — Frustules  ter- 
minal on  a  thick,  branched  stipes,  ge- 
minate linear,  trimcate  ;  valves  linear, 
inflated  at  centre  and  ends  ;  striae  36  in 
•001".  SBD.  i.  p.  74,  pi.  12.  f.  103.= 
Exilaria  fulgens,  Grev. ;  Licmophora 
fulgens,  KB.  1. 13.  f.  5.  Marine.  Europe 
and  America.     6^111  .^o) 

S.  crystallina  (Ag.,  K.). — Frustules 
very  large,  on  a  thickish  abbreviated 
stipes;  valves  linear,  inflated  at  centre 
and  apices ;  strife  distinct,  26  in  -001". 
KB.  p.  69, 1. 16.  f.  1 ;  SBD.  pi.  12.  f.  101. 
=  Diatoma  crystallina,  Ag.  Marine. 
Europe.     1-60"  to  1-48". 

S.  superha  (K.).  —  Stipes  somewhat 
elongated;  valves  stout,  linear-lanceo- 
late, with  rounded  ends ;  striae  verv  di- 
stinct, 27  in  -001".  KB.  p.  69,  t.  15. 
f.  13.  SBD.  i.  p.  74,  pi.  12.  f.  102. 
Marine.     Em'ope. 

S.  Dalmatica  (K.). — Stipes  somewhat 


elongated  and  branched ;  frustides  large, 
linear,  slightly  and  gradually  attenu- 
ated at  the  subtruncate  ends.  KB. 
p.  69,  t.  12.  f.  2.  Marine.  Adriatic  Se^. 
Frustides  terminal  on  the  branches. 
1-240". 

S.  rohusta,  n.  s.  —  Frustules  linear ; 
valves  elliptical,  ends  roimded.  Striae 
20  in  -001",  interrupted  by  three  equi- 
distant longitudinal  lines.  -0120"  to 
•0175''.     Algae,  Corsica,    (vin.  3.) 

S.  giyantea  (Lobarz.). — Frustides  very 
long,  delicate,  somewhat  twisted,  linear, 
truncate  ;  valves  very  narrow,  with  di- 
lated, obovate  apices.  Lobarzewsky, 
Limisea,  1840,  p.  276,  t.  6 ;  KSA.  p.  48. 
Marine.     Dalmatia. 

7  *  Frustules  connected  in  tablets,  at 
length  separating,  and  adhering  by 
alternate  angles,  as  in  Diatoma. 

S.  rumpens  (Kiitz.), — Tablets  affixed  ; 
frustules  very  narrow  linear,  with  tumid 
obtuse  apices,  adhering  by  alternate 
angles.  KB.  p.  69,  1. 16.  f.  6.  Brackish 
water.     German  coast. 

Doubtful  species  from  Ehrenherg. 

S.  australis.  —  Linear,  sti-iated,  with 
attenuated,  obtuse  apices  in  both  views. 
ERBA.  1840;  Microg.  pi.  1.  1.  f.  3.  In 
siliceous  schist  from  the  Philippine 
Islands.     1-432". 

S.  j3rt/(Y/cea. — Very  narrow,  smooth, 
with  subacute  apices.  EM.  pi.  1.  1.  f.  1. 
With  the  last.     1-480". 

S.  iticurva.  —  Linear,  very  narrow, 
flexuose,  smooth,  round,  or  equally 
quadrangidar.  ERBA.  1844,  p.  272. 
Bermuda.  1-288".  Perhaps  a  Spongo- 
lithis. 

S.  rostrata  (EM.  pi.  9.1.  f.4,  and  pi.  14. 
f,  44^. — Fossil.  France  and  Germany. 
Valves  elongated,  slender,  linear,  with 
contracted,  conic  apices,  and  transverse 
striae. 

S.  elegans,  Asia ;  S.  striata,  Asia ; 
S.  lineata,  Asia ;  S.  subulata,  Africa ; 
S.  curvata,  America. 

S.  doliolus  (Wallich).  —  Frustules 
linear ;  valve  subarcuate,  pseudo-nodide 
absent.  Stri^  30  in  -001".  -0020"  to 
•0050".  Salpae.  Indian  Ocean,  Atlantic. 
WaUich,  TMS.  viii.  p.  48,  pi.  2.  f.  20. 


Genus  DESMOGOI^IUM  (Ehr.). — We  are  unacquainted  with  the  characters 
of  this  genus  ;  Ehrenberg's  figures  of  it  seem  to  show  a  relation  to  Synedra, 
the  tablets  (not  single  frustules)  being  attached  to  each  other  by  a  connecting 
substance,  end  to  end — an  arrangement  which  simulates  a  filament. 


790 


SYSTEMATIC  HISTOEY  OF  THE  IKFTJSOEIA. 


Desmogonium  Gmanense. — EM.  t.  34. 
5  A.  f.  3.  Apparently  not  very  uncom- 
mon, since  Ehrenberg  gives  about  50 
habitats  in  Asia,  Africa,  and  America. 


(xv.  13.)  Frustiiles  not  stipitate;  valves 
Tvitliout  longitudinal  ridges,  mostly 
broader  than  the  front  view. 


Genus  DIMEREGRAMMA  (N.,  G.). — Fnistiiles  quadrangular,  two  or  more 
together;  valves  scarcely  broader  than  front  ^dew,  having  the  transverse 
costae  or  strige  interrupted  by  a  smooth,  longitudinal  median  line.  The  frus- 
tiiles are  united  as  in  Denticula  or  Odontidium,  from  which  genera  it  is 
distinguished  by  the  longitudinal  median  line.  The  structure  is  probably 
the  same  as  in  Staui'osira  (E.),  the  description  of  which,  however,  is  altogether 
inapplicable  to  many  of  the  species  here  assembled. 


DiMEEEGRAMMA  miiior  (Greg.).  — 
Front  view  with  convex  striated  margins, 
constricted  beneath  the  conic  angles ; 
valves  narrow  lanceolate,  A\dth  from  18 
to  20  strong  costae  in  -001" .  =  De?iticula 
mbior,  GDC.  p.  23,  pi.  2.  f.  35.  Marine. 
Scotland. 

D.  capitatmn  (Greg.). — Front  view 
vnt\\  convex,  obscurely  striated  margins, 
constricted  beneath  the  dilated  roundish 
a])'ices.  =  Denfictdaf a  capiUda,  Greg  I.e. 
p.  22,  pi.  2.  f.  31.  Marine.  Scotland. 
Is  larger  than  D.  namim,  with  roimded 
apices.     Side  view  unknown. 

D.  nanmn  (Greg.). — Front  ^dew  with 
convex  margins,  constricted  beneath  the 
conic  angles ;  valves  broad,  obtusely 
rhomboid,  Tvith  rather  fine  striae.  =i)e;i- 
ticida  nana,  Greg  I.  c.  p.  23,  pi.  2.  f.  34. 
Marine.     Scotland,     (iv.  33.) 

D.  distans  (Greg.). — Front  view  con- 
stricted beneath  the  conic  angles ;  valves 
broad,  rhombic-lanceolate,  with  strong, 
short  marginal  costae,  and  a  lanceolate, 
blank  median  s-^ace.  =  Deidicida  distans, 
Greg  I.e.  p.  23,  pi.  2.  f.  36.  Marine. 
Scotland.  Is  larger  than  I),  minor,  and 
its  valves  broader,     (iv.  34.) 

D.  Rhombus  =  Fragilaria  ?  Rlwmhus, 
EM.  pi.  8.  1.  f.  16.  Fossil.  Hungary. 
Valves  broadly  rhomboid,  with  marginal 
costae,  and  a  smooth  median  space. 

D.  fidnim  (Greg.). — Front  view  elon- 
gated, with  striated  margins,  constricted 
beneath  the  dilated  apices ;  valves  nar- 
row lanceolate,  with  dilated,  subcapi- 
tate  apices ;  striae  monilifonn,  nearly 
reaching  the  centre.  =  Dentieula  fidva, 
GDC.  p.  24,  pi.  2.  f.  38.  Marine.  'Scot- 
land. 

D.  marinum  (Greg.). — Front  view 
elongated,  linear,  with  striated  margins 
and  slightly  produced  angles;  valves 
linear,  yvith.  gibbous  middle,  obtusely 
conic  apices,  and  about  10  coarsely 
monilifomi  striae  in  -001" .  =  Dcfdiada 
marina,  Greg  /.  e.  p.  24,  pi.  2.  f.  39. 
Marine.     Scotland. 


j  D.  midahile  (Sm.). — Filaments  elon- 
gated ;  valves  oblong  or  lanceolate,  with 
20  marginal  costae  in  -001".  =  Odotdidium 
mufabile,SBJ).  ii.  p.  17,  pi.  34.  f.  290; 
Frac/ilaria  amjjiiioxys,  EM.  pi.  39.  3. 
f.  53.  Fresh  water.  Europe. 
I  D.  Leptoceros  (E.). — Valves  rhomboid- 
linear,  with  longly  attenuated,  acute, 
straight  ends,  finely  striated  margins, 
and  a  smooth  median  s^ace.=  Fragilaria 
Leptoceros,  EEBA.  1844,  p.  82 ;  Odonti- 
dium Leptoceros,  KSA.  p.  13.  North 
America. 

D.  sinuatiim  (Thwaites). — Front  view 
linear,  truncate ;  valves  rhomboid-lan- 
j  ceolate,  with  slightly  uudidated  margins ; 
j  striae  delicate,  52  in  -001" ;  costae  inter- 
rupted, 10  in  -001".  =  De?dieuIa  sinuata, 
SBD.  ii.  p.  21,  pi.  34.  f.  295.  Fresh 
water.     Britain,     (w.  12.) 

D.  Tahellaria  (Sm.).  —  Filaments  fra- 
gile ;  A^alves  with  constricted  or  inflated 
middle,  rostrate  apices,  and  36  delicate 
costae  in  -001".  =  Odontidium  Tahellaria, 
SBD.  ii.  p.  17,  t.  34.  f.  291.  a,  valves 
inflated  at  the  m\&dlQ,  =  Staurosira  con- 
siruens,  Eh.  ?  /3,  valves  constricted  at 
the  middle,     (iv.  35.) 

D.  hirostris  (E.). — Very  minute;  valves 
lanceolate,  suddenly  rostrate,  acute; 
strii©  interrupted  by  a  median  line.= 
Fragilariahirostris,  ERBA.  1844,  p.  342; 
Microg.  pi.  38  a.  2.  f.  8.  Fossil.  Ger- 
many. 1-3120".  Has  nearly  the  cha- 
racters of  a  Staurosira,  Fh. 

D.  informe  (S.). — Valves  elliptical, 
with  an"  irregular  inflation  at  the  centre, 
and  hence  subcruciform ;  costae  18  in 
•001."=  Odontidium  informe,  S  Annals, 
1857,  p.  10,  pi.  1.  f.  12.  Fresh  water. 
France. 

D.  Harrisonii  (Sm.).  — Frustules  fre- 
quently adhering  by  their  angles ;  valves 
cruciform,  with  rounded  lobes ;    costae 


distinct,  13    in     -001". 


Odontidium  ? 


Harrisonii,  SBD.  ii.  p.  18,  pi.  60.  f.  373. 
Fresh  water.  Hull.  The  valves  in  fonu 
resemble  those  of  a  small  Tetracyclus, 


OF  THE  SrRIEELLEJE. 


791 


but  have  interrupted  costae ;  the  front 
view,  too,  is  very  diflerent.     (pnu.  6.) 

D.  jfintiatum  (E.). — Valve  cruciform, 
with  angular  lobes  ;  costae  as  in  D.  Har- 
risonii.-=Staurosi7'a  pinnata,  EM,  t.  5.  2. 
f.  24;  Odontidium  Harrisonii,  ^,  Roper, 
MJ.  ii.  p.  6,  f.  6.  Eiu'ope  and  America, 
(\aii.  4.) 

D.  speciosum  (Brightwell).  —  Valve 
subcruciform  or  rhomboidal  ;  angles 
roimded,  naked ;  costse  short,  distinct,  IG 
on  each  side.  =  Odontidium  speciosum, 
BrightweU,  JMS,  vii.  p.  180,  pi.  9.  f.  8. 


Doubtful  species. 

D.  Surirella  =  Fragilaria  Surirella, 
EM.  pi.  39.  3.  f.^  54.  Frustules  large, 
broadly  linear,  mth  rounded  ends  and 
marginal  costae. 

D.  Bcddjickii  (Brightwell).  —  Valve 
ovately  rhomboidal ;  costse  about  20  on 
each  side,  distinct,  reaching  nearly  to 
the  ends,  but  leaving  a  linear  open  space 
do^\^l  the  centre.  In  a  clay  or  earthy 
deposit  from  Baldjick,  Mr.  Nonnan.=: 
Odontidium  Bcddjickii,  Brightwell^  /.  c. 
p.  180,  pi.  9.  f.  10. 


Genus  STAUROSIEA  (Eh.).—''  The  form  of  this  genus  is  that  of  qna- 
di-angular  Eragilarioe  ;  it  is  distinguished  from  the  much  larger  forms  of  the 
allied  genus  AmjDhitetras  by  the  absence  of  (pseudo-)  openings  at  the  four 
angles." — EEBA.  1843,  p.  45.  The  above  is  the  only  notice  of  this  genus  we 
have  met  with,  the  resemblance  to  Amphitetras  is  evidently  very  slight. 
Erom  Ehrenberg's  figui'es,  Staurosira  seems  to  contain  forms  allied  to  Odon- 
tidium and  Eragilaria,  which  have  the  valve  so  inilated  at  the  centre  as  to 
appear  4-lobed,  This  character,  however,  is  uncertain,  since  Professor  Smith 
shows  that  the  same  species  has  the  valve  sometimes  inflated,  and  sometimes 
constricted  at  the  middle. 


SxAUROsrRA  construens  (E.).  —  Very 
small,  smooth ;  valves  spindle-shaped, 
with  the  produced  angles  somewhat  un- 
equal. EM,  several  figures.  Asia, 
Africa,  and  America,  (xv.  5.)  1-600". 
Compare  with  Dimeregramma  Tahel- 
laria. 


S.  amphilepta  (E.). — Minute,  smooth, 
two  of  the  produced  angles  larger  and 
more  slender  than  the  others. 

S.  trigongyla,  Asia;  S.  Epidendritim, 
Chili ;  S.  Mea:icana,  Mexico ;  S.  trica- 
rinata,  Mexico, — These  species  (Ehren- 
berg's) are  known  to  us  only  by  name. 


G^nns  EHAPHOJ^EIS  (E.). — Frustules  simple,  free  or  shortly  stipitate : 
front  view  narrow  linear ;  valves  much  broader,  with  transverse  dotted  striae 
and  a  median  longitudinal  line.  Marine.  Ehaphoneis  diifers  from  Cocconeis 
and  Naviciila  by  the  absence  of  a  central  nodule.  The  frustule  has  no  alae ; 
its  striae  are  usually  distinctly  moniliform  and  divergent,  and  its  median  line 
more  conspicuous  than  in  TryblioneUa.  We  have  not  thought  it  desirable  to 
separate  Doryphora ;  for  it  is  doubtful  whether  Kiitzing's  only  species  is  even 
specifically  distinct  from  some  forms  still  retained  by  lum  in  this  genus. 


Rhaphoist.is  Amphiceros  (Ehr.).  — 
Valves  lanceolate,  about  three  times 
as  long  as  broad,  with  produced,  styli- 
form  apices,  and  fine,  dotted  transverse 
stri«.  ERBA.  1844,  p.  87 ;  M.  t.  18.  f. 
82.  =  Cocconeis  Amphimros,  E.  1840 ; 
Doryphora  Amphiceros,  I^IB.  p.  74 ;  SBD. 
i.  pi.  24.  f.  224.  Marine.  Europe  and 
America,  (xiv.  21.)  1-576".  Striae  18 
to  20  in  1-1200".  Ends  suddenly  con- 
tracted and  prolonged  into  a  beak. 

R.  Fusus  (E.). — Valves  slender,  linear- 
lanceolate,  usually  fom-  times  as  long  as 
broad,  with  styliform  apices,  and  17  or 
18  fine,  transverse,  granulated  striae  in 
1-1200".  ERBA.  1844,  p.  87.  Fossil. 
Virginia.  1-720".  Strongly  akin  in  habit 
to  Fragilaria  Amphiceros,  but  difters  by 
its  median  suture. 


R.  Leptoceros  (E.).  —  Valves  long 
lanceolate,  quadi'angidar,  rhomboid,  three 
times  as  long  as  broad,  with  long  styli- 
form apices  and  fine,  granulated  trans- 
verse striae.  ERBA.  1844,  p.  87.=i2. 
Oregonica,  EM.  pi.  18.  f.  83.  Fossil. 
America.  1-720".  Striae  generally  18 
in  1-1200".  Has  the  habit  of  i2.  Amphi- 
ceros, but  with  much  longer  beaks. 

R.  gemmifera  (E.).  —  Large  ;  valves 
elongated  lanceolate,  with  long  gradually 
attenuated  apices,  usually  three  times 
as  long  as  broad  ;  striae  strongly  gi-anu- 
lated,  10  in  1-1200".  ERBA.  1844,  p.  87. 
Fossil.     Mai7land.     1-300". 

R.  iwetiosa  (E.).  —  Large  ;  valves 
broadly  lanceolate,  rhomboid,  generally 
twice  as  long  as  broad ;  apices  gradually 
attenuated  into  beaks;  striae  stout, granu- 


'92 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


ERBA.  1844, 
1-480".  Stri« 


lar,  like  series  of  pearls, 
p.  87.  Fossil.  Maryland. 
11  in  1-1200". 

R.  Rhombus  (E.).  —  Small ;  valves 
broadly  lanceolate,  rnomboid,  sometimes 
suborbicular,  scarcely  longer  than  broad, 
with  short  rostrate  apices  and  line  gra- 
nulated strict.  ERBA.  1844,  p.  87 ;  M. 
pi.  33.  13.  f.  19.  Cuxhaven,  Virginia. 
1-1152"  to  1-864".  Striae  20  to  21  in 
1-1200". 

R.    scalar  is   (E.). 
acutely    lanceolate, 


—  Valves 
furnished 


slender, 
with    a 


double  series  of  striae  and  window-like 
crystalline  spaces.  ERBA.  1844,  p.  271. 
Fossil.  Bermuda  deposit.  Diameter 
3-960".     Stride  9  in  1-1200". 

R.  angusta  (E.).  — Valves  elongate 
lanceolate,  with  obtuse  apices,  24  striae 
in  1-1200",  and  no  median  smooth  space. 
ERBA.  1844,  p.  364.     India. 

R.  lanceolata  (E.). — Valves  rhomboid- 
lanceolate  with  obtuse  apices,  21  striae 


ERBA.    1844,   p. 
13.      India,  China, 


364; 
and 


smooth  space. 
M.  pi.  34.  7.  f. 
Japan. 

R.  Indica  (E.).  —  Valves  elliptic- 
lanceolate  with  obtuse  apices,  15  striae 
in    1-1200",    and     a    linear-lanceolate 


median   space.     ERBA. 
India  and  Japan. 


1844,  p.   365. 


R.  fasciolata  (E.).  —  Large  ;  valves 
elliptic-lanceolate,  twice  as  long  as  broad, 
with  strong,  finely  granulated  striae  in 
transverse  fasciae.  ERBA.  1844,  p.  204  \ 
M.  pi.  35  A.  22.  f.  16.  Antarctic  Sea. 
Ehrenberg's  figure  represents  the  valve  as 
elliptic,  with  transverse  band-like  series 
of  short  longitudinal  striae,  alternating 
with  smooth  spaces,  and  interrupted  by 
a  smooth  longitudinal  median  line. 
(?  Lower  valve  of  a  Cocconeis.) 

R.  Scutellum  (E.). — Valves  elliptic, 
longer  than  broad,  with  12  or  13  stout, 
crenidated  striae  in  1-1200".  ERBA. 
1844,  p.  204;  M.  pi.  35  a.  1.  f.  5.  Ant- 
arctic Sea.  1-864".  (?  Lower  valve  of 
a  Cocconeis.) 

'R.faseiata  (E.).  — Microg.  pi.  35  a.  9. 
f.  8.  India.  Valve  elliptic,  with  broadly 
rounded  ends,  a  median  line,  transverse 
fasciae  of  longitudinal  lines  alternating 
with  smooth  transverse  bands,  and  t^vo 
series  of  marginal  striae.  (?  Lower  valve 
of  a  Cocconeis.) 

Species  (Eh.)  known  to  us  only  by  name. 

R.  setacea,  Sandwich  Islands ;  R. 
Entomon,  Asia  Minor ;  R.  rhomboides, 
Ganges ;  R.  Ganc/etica,  Ganges ;  R. 
Icevis,  India ;  R.  Africana,  South  Africa ; 
R.  Digitus,  Demerara. 


Genus  TRYBLIONELLA  (S.).  — "  Frustules  simple,  free,  elHptical  or 
linear ;  valves  plain ;  alae  submarginal  or  obsolete,  canaliculi  inconspicuous, 
parallel." — Smith.  Tryblionella  is  another  genus  separated  from  SurireUa 
by  Professor  Smith,  who  says  that  it  "  differs  from  Campylodiscus  in  the  more 
elongated  form  of  its  frustules  and  the  absence  of  the  bend  in  its  valves  ;  the 
canaliculi  are  also  more  minute,  and  parallel  rather  than  radiating.  It  agrees 
with  Surirella  in  the  presence  of  alae ;  but  these  arise  from  the  disk."  Mr. 
Roper  considers  that  TryblioneUa  is  distinguished  from  SurireUa  by  its  fine 
(often  obsolete),  parallel  transverse  striae ;  whereas  the  latter  is  furnished  with 
canaliculi  or  costte,  which  are  more  or  less  divergent. 

T.  7iavicularis  (Breb.).  —  Front  view 
oblong,  with  truncate,  slightly  winged 
ends;  lateral  view  eUiptic-acmninate ; 
costae    distinct,    marginal  ;     alae    con- 


Tryblionella  circumsuta  (B.).  — 
Lateral  view  elliptic-oblong,  with  a  faint, 
longitudinal  median  line  (indistinct  or 
obsolete),  parallel  transverse  striae,  and 
marginal  gland-like  dots ;  alae  very 
short.  =  Surirella  circumsuta,  Bailey,  MO. 
pi.  2.  f.  36 ;  T.  Scutellum,  SBD.  i.  p.  35, 
pi.  10.  f.  74.  Marine.  America,  Britain. 
Professor  Bailey  describes  it  as  having 
a  minutely  granulate  sm^face,  and  a 
scarcely  perceptible  median  constriction. 

T.  gracilis  ( S.). — Front  view  linear,  with 
attenuate  extremities  and  truncate  apices; 
lateral  view  linear-acuminate  ;  costae 
parallel,  extending  to  median  line ;  alae 
distinct.  SBD.  i.  p.  35,  pi.  10.  f.  75.  Fresh 
and  brackish  waters.    Lewes,    (iv.  36.) 


spicuous.  =  Surirella  navicularis,  Breb,  in 
KSA.  p.  36  ;  T.  marginata,  SBD.  i. 
p.  35,  pi.  10.  f.  76.  Fresh  and  brackish 
waters.     France ;   England. 

T.  acuminata  (S.).  —  Lateral  view 
linear,  with  attenuated  ends  and  delicate, 
interrupted  transverse  striae ;  alae  obso- 
lete ;  canaliculi  obscure.  SBD.  i.  p.  36, 
pi.  10.  f.  77.  Marine  and  brackish 
waters.  Britain.  -0012"  to  -0021". 
Stria?  31  in  -001".     (iv.  37.) 

T.  angustata  (S.).— Resembles^,  acumi- 
nata ;  but  its  striae  are  continuous.  SBD. 


OF  THE  STJRIKELLE^. 


'93 


p.  36,  pi.  30.  f.  262.  Fresh  water.  England. 
•0021"  to  -0040".     Strife  36  in  -OOl". 

T.  levidensis  (S.). — Lateral  view  linear, 
with  subacute  extremities ;  costoe  very 
distinct,  parallel,  extending-  to  the  cen- 
tral line.  SBD.  ii.  p.  89.  Brackish 
water.     Cork  City  Park. 

T.  punctata  (S.). — Lateral  view  ellip- 
tic, with  acuminate  ends  and  parallel, 
transverse,  moniliform  strise ;  canaliculi 
obsolete.  SBD.  i.  p.  36,  pi.  30.  f.  261. 
Marine.     Sussex. 

T.   constricta  (Greg.). — Lateral  view 


panduriform,  with  apiculate  ends  and 
numerous,  delicate,  diagonal,  punctated 
striae ;  costa  obsolete.  Greg,  in  MJ. 
iii.  pi.  4.  f.  13.  Marine.  Britain.  "  Its 
form  is  that  of  Cymat(ypleura  Soka,  but 
it  is  very  much  smaller.". — Greg. 

T.  apiculata  (Greg.). — Narrow,  linear, 
slightly  constricted  in  the  middle,  with 
apiculate  extremities  and  about  45  fine 
but  distinct,  transverse,  dotted  striae  in 
•001".  Greg,  in  MJ.  v.  p.  79,  pi.  1.  f. 
43.  Scotland.  -0015"  to  -0017".  Keel 
often  strongly  marked. 


Genus  CYMATOPLEURA  (S.).— Frustiiles  free,  in  front  view  linear,  with 
undulated  margins  ;  laterally  broader,  and  marked  \vath  transverse  bars. 
Aquatic.  This  genus,  instituted  by  Smith,  is  very  distinct,  and  may  be 
recognized  by  the  lateral  surfaces  projecting  in  the  front  view  in  an  undu- 
lated manner,  the  central  portion  being  separated  from  the  undulations  by  a 
marginal  row  of  dots.  The  lateral  view  is  usually  very  much  broader  than 
the  front,  which  often  renders  it  difficult  to  obtain  a  satisfactory  sight  of  the 
latter.  The  lateral  surfaces,  however,  sufficiently  identify  the  genus,  as  the 
broad,  transverse,  shade-like  bands  or  bars  which  correspond  with  the  undu- 
lations are  characteristic.  The  striae  are  generally  obscure  or  obsolete,  and 
the  median  longitudinal  line  is  less  evident  than  in  Surii'eUa ;  the  margin 
is  usually  furnished  with  conspicuous  gland-like  dots.  "  The  undulations  of 
the  valves  separate  Cymatopleui-a  from  TryblioneUa  and  Surirella  ;  the  absence 
of  alse  and  canaliculi  are  fiu'ther  characters  which  leave  no  room  for  hesita- 
tion as  to  its  distinctness."     (Smith.) 


Cymatopleuba  Solea  (Breb.,  S.). — 
Frustule  elongate;  laterally  panduri- 
form, with  more  or  less  attenuated  ends, 
sometimes  apiculated ;  striae  delicate,  8 
in  1-1200".  SBD.i.  p.  36,  f.  78.  =  Surirella 
Solea,  Breb.  in  KSA.  p.  34;  S.  Librile, 
E.  ;  Sphinctocystis  librilis,  Hass  BA. 
p.  102,  3.  Yar.  j3,  ends  apiculated,  =  C. 
apiculata,  S.  I.  c.  p.  37,  f.  79.  Common, 
Asia,  Africa,  America,  Europe,  (ix.  155 ; 
XVI.  9.)  Frustules,  in  both  \dews,  many 
times  as  long  as  broad ;  undulations  six. 
The  ends,  in  the  lateral  \dew  are  always 
attenuated ;  but  theu'  apices  vary,  and  are 
sometimes  obtuse,  sometimes  apiculate ; 
and  therefore  we  concm-  with  M.  de  Bre- 
bisson  in  uniting  C.  apiculata,  Smith, 
with  this  species. 

C.  heterocyma  (Nageli).  —  Lateral 
view  panduriform,  with  16  marginal  striae 
in  1-1200" ;  front  view  broadly  linear, 
twice  undulately  twisted,  with  six  mar- 
ginal {olds.  =  Surirella  heterocyma,  KSA. 
p.  889.     Switzerland.     1-240". 

C.  elliptica  (Breb.,  S.). — Lateral  view 
elliptic,  with  three  to  five  transverse  bars ; 
ends,  in  general,  slightly  attenuated. 
SBD.  p.  37,  pi.  10.  f.  80.  =  SurireUa  oo- 
phcena,  E.  (according  to  Kiitzing)  ;  S. 
undulata,  EM. ;  S.  undata,  EM, ;  S.  pli- 


cata,  EM.  pi.  15  a.  f.  50,  51  ? ;  S. 
Kiitzim/ii,  Perty,  Diat.  p.  201,  t.  17.  f.  2. 
Aquatic.  Asia,  Africa,  America,  Europe, 
(ix.  149;  x\^.  7,  8.)  Professor  Kiitzmg 
describes  the  frustules  as  ovate  ;  but  we 
have  always  found  them  elliptic.  Un- 
dulations three  to  five;  lateral  surfaces 
obscurely  striated  and  furnished  with 
marginal  gland-like  dots.  We  have  re- 
ferred the  Surirella  plicata,  E.,  to  this 
species,  because  of  its  habitat,  although 
its  figure  in  the  ^Microgeologie'  agrees 
better  with  that  of  C.  Hibernica. 

C.  Hihernica  (S.).  —  Lateral  view 
broadly  elliptic,  ^dth  produced  ends ; 
striae  obscm^e.  SBD.  i.  p.  37,  pi.  10.  f. 
81.  Ireland,  France.  Undulations  about 
three ;  length  1-370"  to  1-220" ;  breadth 
two-thirds  the  length. 

C.  Regula  (E.). — Lateral  view  linear, 
with  cimeate  ends  and  six  transverse  bars. 
=  Surirella  Regula,  KB.  t.  28.  f.  30. ;  C. 
parallela,  Smith,  BD.  pi.  30.  f.  263. 
Mexico,  France,  England.  Habit  and 
size  of  C.  Solea,  but  not  panduriform ; 
pinnules  10  in  1-1200",  nearly  obsolete. 

C.  Ovum  (Nageli).  —  Lateral  view 
broadly  oval,  wdtli  8  marginal  striae  in 
1-1200" ;  front  view  broadly  linear, 
straight;    margin    Avith    five    marginal 


794 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


folds.  =  Surirella  Ovum,  Nageli  in  KSA. 
p.  889.    Switzerland.    1-360"  to  1-280". 


The  characters  given  are  insufficient  to 
distinguish  it  from  C.  elliptica. 


Genus  SURIRELLA  (Turp.,  E.,  S.).  —  Erustules  simple,  free;  margin 
striated ;  lateral  smfaces  broader  than  the  front  view,  with  a  smooth  median 
lon^tudinal  line ;  "  margins  produced  into  aloe,  canalicuH  distinct,  usually 
parallel"  (Smith).  SuiireUa  thus  Hmited  by  Professor  Smith  becomes  a  much 
more  natm^al  genus  than  it  was  constituted  by  preceding  authors :  he  says, 
*'  It  is  weU  distinguished  from  TryblioneUa  by  the  prominency  of  its  alae,  the 
distinctness  of  its  canaUcuH,  and  the  usually  cuneate  form  of  its  frustules ; 
mth  no  other  is  it  at  aU  likely  to  be  confounded." 

few,  reaching  the  median  line,  central 


*  Frustules  panduriform. 

SuRiEELLA  constricta  (E.).  —  Large, 
oblong,  in  lateral  view  panduriform,  with 
a  median  line  and  iutramarginal  crena- 
tions.  EM.  pi.  14.  f.  37.  Benticula  con- 
stricta, KB.  t.  3.  f.  62  ?.  Aquatic.  Berlin, 
(xiii.  3.)  Ehrenberg's  figure  in  the  ^Mi- 
crogeologie'  seems  a  true  species  of  this 
genus;  and  different  as  is  that  oiDenticula 
constricta  in  Kiitzing's  work,  yet,  as  it  was 
copied  from  a  figure  given  by  Ehrenberg 
in  an  earlier  work,  the  differences  are  pro- 
bably due  to  the  imperfect  representation. 

S.'  Smithii  (K.). — Front  ^dew  broadly 
linear,  with  truncate  ends  and  rounded 
angles;  lateral  view  panduriform,  with 
attenuated  ends ;  costge  delicate,  reach- 
ing the  median  line,  which  is  often  in- 
flated. =  ^.  constricta,  SBD.  i.  p.  31,  pi.  8. 
f.  59.  Brackish  water.  England.  Alae 
conspicuous,  enclosing  an  oblong  space. 
1-300".  The  shape,  in  front  view,  re- 
sembles that  of  S.  hiseriata,  but  the  costse 
are  much  finer. 

S.  Antarctica,  EM.  pi.  35  a.  2.  f.  20. 
Antarctic  Sea.  "We  have  seen  no  de- 
scription of  this  species.  Ehrenberg's 
figure  shows  the  lateral  view  panduri- 
form, vdth  rounded  ends  and  strongly 
marked  striae,  which  nearly  reach  the 
median  line. 

S.  didijma  (K.). — Oblong,  with  trun- 
cate ends,  constricted  middle  and  punc- 
tated margins.  KB.  p.  60,  t.  3.  f.  67. 
Submarine  waters.  Isle  of  Wangeroog. 
1-600".  This  appears  to  us  a  doubtful 
species  of  Surirella ;  for  Kiitzing's  figure 
seems  to  represent  a  frustide  constricted 
in  the  front  view,  as  it  shows  a  linear 
median  portion  truncated  at  its  ends. 

S.  panduriformis  (Rab.).  —  Resembles 
S.  didyma,  but  is  stouter,  and  its  mar- 
ginal dots  appear  stalked.  Rab.  p.  29, 
t.  3.  f.  9.     Italy. 

2  *  Lateral  vieic  lanceolate  or  oblong,  with 
its  ends  usually  equally  cdtenuated. 

S.  Craticula  (E.). — Lanceolate;  costas 


ones  divergent.  SBD.  pi.  9.  f.  67.  Aquatic. 
Australia,  Asia,  Africa,  America,  Britain. 
(XII.  19,  20.)  Costfe  7  in  1-1200". 
1-288".  The  central  costse  are  usually 
more  distant,  leaving  a  transverse  smooth 
space  bisected  by  the  median  line. 
Smaller  than  S.  hiseriata ;  its  costce  fewer 
and  more  divergent. 

S.  megaloptera,  EM.  pi.  33.  1.  f.  17. 
Eg}^t.  The  figure  resembles  that  of 
*S',  Craticula ;  but  the  costse  are  all  paral- 
lel, and  the  median  line,  as  well  as  costse, 
are  interrupted  at  the  centre  by  a  broad, 
transverse  band. 

S.  hiseriata  (Breb.). — Front  view  qua- 
drilateral, with  conspicuous  alse  ;  lateral 
view  oblong-lanceolate,  with  broad  costse, 
which  usuallv  reach  the  median  line. 
SBD.  i.  p.  30, "pi.  8.  f.  57.  =  .^.  hifrom,  E. 
Common.  (x\t:.  20-26.)  Differs  from 
S.  splendida  Iby  its  parallel  sides  in  front 
\4ew.  Its  angles  are  rounded,  and  the  alse 
enclose  an  oblong  space;  its  costse  are 
conspicuous  in  both  views.  1-210"  to 
1-100".     Sti-i^  3L  in  1-1200". 

S.  decora  (E.). — Large,  linear-lanceo- 
late, with  equal,  attenuated  ends  and 
four  or  five  marginal  costse  in  1-200". 
EM.  pi.  5.  3.  f.  23.  America,  Ireland. 
Ehrenberg's  figures  are  oblong  lanceo- 
late, one  of  them  constricted. 

S.  rejlexa  (E.).  —  Lanceolate,  with 
nearly  equal,  slightly  refiexed,  subacute 
ends,  a  distinct  median  suture,  and  strong, 
short  strise,  in  the  middle  three  or  foiur 
in  1-1152".  EM.  pi.  33.  11.  f.  13.  Fossil. 
Connecticut. 

S.  leptoptera  (E.). — Lanceolate,  with 
nearly  equal,  acute  ends,  a  distinct,  di- 
lated median  suture,  and  dense  trans- 
verse strise,  which  in  the  middle  are 
6  in  1-1152".  KSA.  p.  36.  Fossil. 
Oregon.  A  specimen  1-456"  long  pre- 
sented 21  strise. 

S.  Oreyonica  (E.).  —  Spathulate,  with 
imequal,  subacute  ends,  a  distinct,  di- 
lated median  suture,  and  strong  strise, 
which  in  the  middle  are  four  or  five  in 


OF  THE  SUEIEELLEiE. 


795 


1-1152".  EM.  pi.  33.  12.  f.  27.  Fossil. 
Oregon.  A  specimen  1-336"  long  pre- 
sented 19  strise.  Ehrenberg's  figiu'e  is 
elliptic-lanceolate,  witli  a  median  line 
dilated  at  the  centre  into  a  large  oval 
form ;  the  striae  short  and  externally  ter- 
minating in  gland-like  dots. 

S.  turgicla  (S.).  —  Elliptic-lanceolate, 
with  tapering,  sometimes  contracted 
ends  and  obtuse  apices ;  costse  few  (4  in 
•001"),  conspicuous,  separated  by  a  me- 
dian lanceolate  space.  SBD.  i.  p.  31, 
pi.  8.  f.  59.  =  >S'.  Caledonica,  EM.  pi.  15  a. 
f.  47  ?  Aquatic.  Ireland.  Distinguished 
by  its  ventricose  centre. 

S.  ohlonc/a  (E.).  —  Oblong-lanceolate, 
with  obtuse  ends,  near  the  margin  si- 
nuoso-dentate.  KSA.  p.  35.  Aquatic. 
Africa;  America;  Mourne  deposit,  Ire- 
land. Ehrenberg's  figures  in  the  ^  Micro- 
geologie'  difier  very  much  in  form,  but 
all  have  the  costEe  confined  to  the 
margin. 

S.  Breuteliana  (Rab.). — Linear-elliptic, 
with  rounded  ends,  five  transverse  costae 
on  each  side,  connected  at  inner  ends  by 
an  imdidated  line,  and  leaving  a  longi- 
tudinal median  space  with  waved  mar- 
gins. Rab  D.  p.  29.  t.  3.  f.13.  Aquatic. 
St.  Kitts. 

S.  crenulata  (E.). — Small,  elliptic-lan- 
ceolate, with  crenulate  margins,  subacute, 
nearly  equal  ends,  and  a  distinct  median 
line;  eleven  crenides  in  1-1152",  extend- 
ing into  striae,  which  do  not  reach  the 
centre.  EM.  pi.  33.  f.  23.  Fossil,  United 
States.     D.  1080". 

%.  microcora  (E.). — Minute,  oblong- 
lanceolate,  with  somewhat  acute  apices, 
and  marked  near  the  margin  with  ten 
delicate  dentations  in  1-1200".  EA. 
p.  136,  t.  2.  1.  f.  34;  KB.  t.  29.  f.  15. 
Asia,  Africa,  America. 

S.  lepida  (E.).  —  Slender,  linear-lan- 
ceolate, one  end  obtuse,  the  other  a  little 
more  attenuated  and  subacute ;  striae  nine 
or  ten  in  1-1152"  j  the  median  line  di- 
stinctly flexuose.  ERBA.  1844,  p.  272 ; 
KSA.  p.  36.     Km-distan.     1-768". 

S.  tenella  (K.).  —  Oblong-lanceolate, 
with  rounded,  obtuse  apices,  and  five, 
rather  lax  transverse  striae  in  1-1200"; 
front  view  oblong,  almost  rectangular, 
with  obtuse  angles.  KSA.  p.  37.  Aquatic. 
Prussia. 

S.  ohtusangula  (Rab.).  —  Small,  lan- 
ceolate, with  cuneate,  attenuated,  obtuse 
ends,  and  six  short  costae  in  1-1200"; 
front  view  oblong,  broadlv  roimded.  Rab. 
p.  29,  pi.  3.  f  27.     Aquatic.     Germany. 

»S.  Aniphioxys  (S.).  —  Elliptic-lanceo- 
late, with  subacute  extremities,  and  nine 


costae  in  -001";  front  view  Imear.  SBD. 
ii.  p.  88.     Haverfordwest. 

S.  angusta  (K.). — Minute,  linear,  with 
cuneate  ends,  rather  obtuse  apices,  and 
11  costae  in  1-1200"  ;  alae  obsolete ;  front 
view  linear,  trimcate.  KB.  t.  30.  f.  52 ; 
SBD.  pi.  31.  f.  260.  Aquatic.  Europe ; 
Lewes. 

S.  apiculata  (S.). — "Elliptical,  ovate, 
smaller  extremity  produced  into  a  linear, 
truncate  apiculum;  costae  15  in  -001"." 
SBD.  ii.  p.  88.  Aquatic.  England. 
Length  of  frustule  -0008"  to  -0012".  "  A 
close  ally,  if  not  a  variety,  of  S.  angiista." 

S.  linearis  (S.). — Minute,  linear,  with 
cuneate  ends,  distinct  transverse  costae, 
and  a  narrow  median  line.  SBD.  i.  pi.  8. 
f.  58=^'.  =  S.  acuminata  (Breb.  MS.). 
Aquatic.  England,  France.  Var.  /S, 
slightly  constricted  at  the  middle,  S. 
p.  8.  f.  58^".  In  the  front  view  this 
species  resembles  a  small  form  of  S. 
hiseriata. 

3*  Lateral  view  with  one  end  broadly 
rounded,  the  other  smaller  (ovate  or 
ovate-ohlong) ;  front  vieiv  usually  cu- 
neate. 

S.  rohusta  (E.).  —  Large,  elongated; 
ovate-oblong,  with  two  stout  costas 
(which  do  not  reach  the  centre)  in 
1-1200".  EM.  pi.  15  A.  f.  43.  S.  nohilis, 
SBD.  pi.  8.  f  63.  Aquatic.  Fossil.  Fin- 
land; Britain.  1-216"  to  1-120".  Di- 
stinguished by  its  large  size,  elongated, 
slightly  tapering  form,  and  large  intra- 
marginal  crenations. 

S.  procera,  EM.  pi.  14.  f.  33.  Berlin. 
The  figure  represents  a  large  species, 
slightly  broader  at  one  end,  with  large 
intramarginal  crenations  as  in  S.  rohusta^ 
but  the  strong  transverse  costae  are  sepa- 
rated only  by  a  narrow  median  band. 

S.  splendida  (E.,  K.).  —  Front  view 
cuneate,  with  rounded  angles  and  pro- 
longed costae ;  lateral  view  ovate-oblong 
with  conspicuous,  diverging  costae  which 
reach  the  median  line ;  alae  distinct. 
EM.  t.  15  a.  f.  44;  SBD.  i.  pi.  8.  f.  62. 
Aquatic.  Common,  both  living  and  fossil, 
(ix.  150-152.)  Var.  ^.  linearis,  smaUer, 
lateral  view  narrow,  slightlv  tapering,  = 
S.  Unearis,  SBD.  i.  pi.  8.  f.  58  a.  1-210" 
to  1-100".  As  the  front  view  has  rounded 
angles,  it  is  not  unlike  the  lateral  one  in 
outline,  but  the  ends  are  broader.  Two 
or  three  times  as  long  as  broad. 

S.  tenera  (Greg.).  —  Narrow  linear- 
oblong,  with  one  end  more  tapering  than 
the  other;  costae  distinct,  reaching  the 
median  line.  Greg  MJ.  iv.  p.  10,  pi.  1. 
f.  38.     Scotland.     It  is  smaller  than  ^S". 


796 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


splendida,  and  its  alse  are  less  conspi- 
cuous; but  it  resembles  that  species  in 
form,  and  we  doubt  whether  it  be 
distinct. 

S.  striatula  (Tui-p.). — Front  view  broad 
cuneate,  with  rounded  angles  and  short 
costae  ;  lateral  view  ovate,  with  distant, 
curved  costse,  which  reach  the  median 
line;  al«  small.  SBD.  i.  pi.  9.  f.  64 
Common.  Resembles  aS".  splendida,  but 
is  shorter  in  proportion  to  its  breadth. 
In  the  front  view  the  central  portion  is 
broader,  the  ends  more  truncate,  the 
costse  shorter,  and  the  alse  less  conspi- 
cuous. Lateral  view  faintly  striated; 
stri£e  8  to  13  in  1-1200".  ( ->%  .  /»;  iW 

S.  limosa  (Bai.  MS.  ?).— Broadly  ovate 
acuminate,  faintly  punctato-striate ;  ca- 
naliculi  short  and  indistinct,  not  reach- 
ing more  than  1-6"  across  the  valve ; 
length  -0073",  breadth  -0035" ;  striae  in- 
distinct, 22  in  -001.  New  Zealand,  Hud- 
son River,  New  York,  Thames  mud. 
Bri  JMS.  vii.  p.  179,  pi.  9.  f.  5. 

S.  h'ems  (E.). — Short ;  form  and  size 
of  S.  striatula,  but  with  16  finer  striae  in 
1-1200".  ERBA.  1844,  p.  272 ;  KSA. 
p.  39.     Kiu'distan.     1-912". 

S.  Testudo  (E.). — Large,  ovate,  obtuse, 
with  12  slender  striae  in  its  length,  which 
is  1-288".  E  l.c.  1840,  p.  24;  KSA. 
p.  39.     Marine. 

S.  Gemma  (E.). — Front  view  narrow 
cuneate ;  lateral  view  broader,  ovate- 
elliptic,  faintly  striated  between  the  de- 
licate, unequally  distant  costae,  which 
reach  the  median  line;  alae  inconspi- 
cuous. KB.  t.  7.  f.  9;  SBD.  i.  pi.  9.  f.  65. 
Common  in  marine  marshes,  (xii.  2-4.) 
Distinguished  from  aS".  striatula  by  its 
much  finer  costae  and  less  conspicuous 
alae,  which  in  the  lateral  view  generally 
coincide  with  the  margins.  Sometimes 
nearly  elliptic.  We  have  rarely  seen  it 
so  narrow  as  Professor  Smith's  figure 
represents  it. 

S.  kevigata  (E.). — Elongated,  smooth, 
with  subequal,  obtuse  ends,  a  distinct 
median  suture,  and  two  longitudinal 
lateral  lines.  KSA.  p.  36 ;  EM.  t.  33. 14. 
f.  24.  Fossil.  United  States.  1-168". 
Ehrenberg's  figure  in  the  '  Microgeologie ' 
is  ovate,  with  a  median  line,  lax  intra- 
marginal    crenations,    and    very    short 

S.  buatimalemis,  EM.  pi.  33.  6.  f.  7. 
America.  Figure  broadly  ovate,  with 
both  ends  much  rounded,  and  minute 
intramarginal  crenations,  without  me- 
dian line  or  costae. 

S.  ichthyocephala  (Rab.).  —  Large, 
ovate-oblong,  with  rounded  ends,  three 


broad,  flexuose  costae  in  1-1200"  and  a 
broad  linear  median  band.  Rab  D.  p.  30, 
pi.  10,  Supp.  f  6.  Italy.  The  figure 
shows  the  costae  cm*ved,  except  the 
middle  one,  which  is  broader  and 
straight. 

S.  cordata  (E.).  —  Ovate-subcordate, 
with  four  lax  striae  in  1-1152",  conti- 
guous in  the  median  line.  ERBA.  1845, 
p.  272 ;  KSA.  p.  39.     Fossil.     Georgia. 

S.  prcetexta  (E.).  — Long  ovate,  more 
than  twice  as  long  as  broad,  with  five 
rather  lax  striaa  in  1-1252",  towards  the 
middle  broadly  interrupted  and  not  con- 
tiguous in  the  median  line,  hence  forai- 
ing  four  series  Avitli  a  broad  linear  me- 
dian space  and  two  smooth  lateral  ones. 
Maritime.  India.  ERBA.  1845,  p.  365 ; 
KSA.  p.  38. 

S.  euglypta(F..). — Small,  ovate-oblong, 
mth  seven  striae  in  1-1200",  which  do 
not  reach  the  centre ;  front  view  cuneate, 
with  rounded  angles  at  larger  end.  EA. 
p.  136,  t.  3.  5.  f.  2.  4;  KB.  t.  28.  f.  27. 
Asia,  Africa,  America. 

S.  uninervis  (E.). — Small,  ovate,  half 
as  long  again  as  broad;  costae  reticu- 
lated at  the  margin,  contiguous  at  the 
slender  median  line,  7  in  1-1152".  KSA. 
p.  38.     Maritime.     India,  Africa. 

S.  Folium  (E.).  —  Ovate,  turgid  and 
obtuse,  slightly  compressed,  with  24  fine 
striae  in  1-1150".  Fossil.  Barbadoes. 
1-540". 

S.  Crumena  (Breb.). — Small,  orbicidar 
ovate,  with  7  or  8  evident  marginal 
stri»  in  1-1200".  KSA.  p.  38.  Aquatic. 
France,  Britain.  Its  suborbicidar  form 
in  lateral  view  distinguishes  it  from 
every  other  species  except  S.  Bright- 
ivellii. 

S.  Brightwellii  (S.).  —  Small,  suborbi- 
cular,  with  one  end  subacute ;  costae 
distinct,  marginal,  10  in  -001";  alae  in- 
conspicuous. SBD.  i.  p.  33,  pi.  9.  f.  69. 
Britain.  According  to  Professor  Smith, 
this  species  is  distinguished  from  S.  Cru- 
mena by  its  coarser  and  more  prominent 
costae  and  distinct  striae  ;  S.  Crumena  is 
also  smaller  and  more  orbicidar. 

S.  oralis  (Breb.). — Small,  ovate-elliptic, 
with  8  marginal  costae  in  1-1200",  and 
one  end  more  attenuated  than  the  other ; 
alae  inconspicuous.  KSA.  p.  33 ;  SBD. 
pi.  9.  f.  68.  Aquatic.  France,  Britain. 
Front  view  oblong-cimeate,  truncate. 
1-360"  to  1-280".  Margin  with  very 
short,  teeth-like  costae.  The  larger  end 
in  lateral  view  is  less  rounded  than  in 
the  allied  species. 

S.  orata  (K.j. — Minute  ovate,  or  ovate- 
elliptic,  with  7  to  9  delicate,  very  short, 


0¥  THE  SUEIKELLE^. 


797 


marginal  costae  in  1-1200" ;  alae  incon- 
spicuous. KB.  pi.  7.  f.  1-4 ;  SBD.  pi.  9. 
f.  70.  Europe,  America.  Front  view 
broadly  cuneate,  truncate.  1-1200"  to 
1-560." 

S.  minuta  (Breb.).  —  Minute,  ovate- 
elliptic,  with  inconspicuous  alae  and  14 
marginal  costae  in  -001".  SBD.  i.  p.  34, 
pi.  9.  f.  73.  France,  England.  -0005"  to 
•0009".  Kiitzing  unites  this  fomi  with 
S.  ovata;  but  M.  de  Brebisson  informs 
us  that  he  is  able  to  distinguish  the  two 
species  when  m  situ  at  the  first  glance ; 
that  the  stratum  of  this  species  is  black 
and  very  mobile,  whilst  that  of  S.  ovata 
is  brown,  and  adheres  more  firmly  to 
the  soil. 

S.  salina  (S.). — Minute,  ovate-oblong, 
with  numerous  minute  marginal  costae 
and  obsolete  alse.  SBD.  i.  p.  34,  pi.  9. 
f.  71.  Marine  or  brackish  waters.  Eng- 
land.    Front  view  wedge-shaped. 

S.  suhsalsa  (S.).  —  Minute,  ovate-lan- 
ceolate, with  8  distinct  costae  and  30 
strias  in  1-1200" ;  alae  conspicuous.  SBD. 
i.  p.  34,  pi.  31.  f.  259.  =6'.  pijgmmi,  EM. 
pi.  35  A  8.  f.  4  ?  Fresh  or  brackish 
waters.     England. 

S.  pmnata  (S.).  —  Minute,  narrow, 
ovate-oblong  or  somewhat  clavate,  with 
large,  subdistant  marginal  costae ;  alae 
obsolete.  SBD.  i.  p.  34,  pi.  9.  f.  72. 
Aquatic.  Lewes.  Front  view  narrow 
cimeate. 

4  *  Lateral  view  with  broadly  rounded, 
rarely  unequal,  ends. 

S.  Lamella  (E.).  —  Large,  narrow 
elliptic,  with  nearly  equal,  broadly 
rouiided  ends ;  intramarginal  striae  and 
granulose  median  area ;  front  view  nar- 
row linear,  truncated.  EM.  pi.  15  a. 
f.  49.  Lough  Moume  deposit.  1-210" 
to  1-180".  Ehrenberg's  figure  has  no 
median  line. 

S.iiosowia(E.). — Narrow  elliptic,  with 
broadly  rounded  ends,  a  narrow  margin 
of  fine  striae,  and  a  smooth  median  area 
with  a  median  longitudinal  line.  EM. 
pi.  33. 14.  f.  25.  Maritime.  India.  Three 
times  as  long  as  broad. 

S.  Patella  (K.).— Elliptic-oblong,  with 
equal,  rounded  ends,  and  four  or  five  mar- 
ginal stria3  in  1-1200".  KB.  t.  7.  f.  5. 
Fossil  at  Franzensbad. 

S.  Peruviana  (E.).  —  Large,  elliptic- 
oblong,  with  equal,  rounded  ends,  and 
about  12  verv  short,  obsolete,  marginal 
costae  in  1-1200".  KB.  t.  29.  f.  72.   Peru. 

S.  amphiamhlya,  EM.  pi.  14.  f.  34. 
Berlin,  The  figure  shows  a  large  elliptic 
form  with  equal,  rounded  ends,  intra- 


marginal crenations,  and  strong,  paraUel, 
transverse  costae,  which  do  not  quite 
reach  the  median  line. 

S.  Mississipica,  EM.  pi.  35  a.  8.  f.  5. 
America.  Ehrenberg's  figure  is  large, 
eillptic-oblong,  with  equal,  roimded  ends, 
and  paraUel  transverse  costae,  separated 
by  a  naiTOw  linear,  longitudinal  median 
band. 

5  *  Lateral  view  with  rounded  ends ;  costce 

ivith  dilated  outer  portion,  and  median 

space  Jinely  striated. 

S.  fastuosa  (E.).  —  Elliptic,  with 
rounded  ends,  rather  distant  costae,  in- 
flated towards  the  margin,  and  a  trans- 
versely striated,  lanceolate  median  space. 
Greg  M J.  iii.  p.  30,  pi.  4.  f.  41.  Marine. 
Common.  Eui-ope,  Asia,  Africa,  Ame- 
rica. Distinguished  from  all  the  pre- 
ceding species  by  its  inflated  costae  re- 
sembling stalked  flowers,  and  by  the 
striated  median  space,  which  is  very 
variable  in  breadth.  Diflers  much  in 
size,  and  is  sometimes  nearly  orbicular  -, 
we  have  never  seen  it  ovate,  as  described 
by  Professor  Smith. 

S.  lata  (S.).  —  Large,  broadly  linear- 
elliptic  or  somewhat  panduriform,  with 
broadly  rounded  ends,  a  transversely 
striated  median  area,  and  distant  cost89 
externally  dilated.  SBD.  i.  p.  31,  pi.  9. 
f.  61.  =  Campylodiscus  productus,  John- 
ston. Marine.  Not  uncommon.  England. 
Differs  from  *S'.  fastuosa  in  its  form,  and 
usually  in  its  larger  size ;  but  the  mark- 
ings are  similar  in  both.  As  Professor 
Gregory  finds  intermediate  states,  they 
may  be,  as  he  supposes,  mere  varieties. 

S.  eximia  (Grev.).  —  Linear-oblong 
with  rounded  ends,  about  18  delicate 
costae  on  each  side,  reaching  the  narrow 
linear-lanceolate,  transversely  striated 
median  space.  Grev  M J.  v.  p.  10,  pi.  3. 
f.  6.  Marine.  West  Indies.  This  ex- 
tremely delicate  and  hyaline  Diatom, 
Dr.  Greville  informs  us,  approaches  S. 
lata  in  form,  slight  constriction,  and  a 
striated  central  space,  but  differs  in  every 
other  respect.  The  costae  equidistant, 
and  as  fine  as  those  of  S.  Gemma  j  alae 
naiTow,  but  conspicuous. 

Doubtful  or  undescribed  ^ecies. 

S.  ?  Cocconeis,  EM.  pi.  35  a.  8.  f.  3. 
Marine.  India,  Africa.  This  species, 
according  to  the  figure,  is  small,  elliptic, 
with  obtuse  ends,  and  parallel  transverse 
costae  separated  by  a  smooth,  narrow- 
lanceolate  median  space. 

S.  Jenneri  (Hassall).  —  Front  view 
linear,  with  rounded  ends,  and  distant, 


798 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


short,  teetli-like  marginal  costse.  Hass. 
Br.  Algae,  p.  439,  pi.  102.  f.  15.  Aquatic. 
Sussex.  Dr.  Hassall  describes  it  as  a 
very  distinct  species,  having  no  relation 
with  S.  biseriata. 

S.  amhigua  (K.).  —  Broadly  oblong, 
with  truncated  ends,  and  4  straight,  ob- 
solete, rather  broad  transverse  striae  in 
1-1200".  KB.  t.  5.  f.  17.  Stagnant  waters, 
Switzerland.  1-264".  Kiitzing's  figure 
apparently  represents  the  front  view,  and 
is  broadly  linear,  with  obscure  transverse 
costfB,  leaving  a  narrow  median  portion. 

S.  Icevis  (K.)-  —  Cylindrical,  elliptic- 
lanceolate,  somewhat  obtuse,  very  smooth 
and  h valine.  KS A.  p.  36.  Marine.  France. 
1-1080". 

S.  attenuata  (Nag.). — Smooth,  linear- 
lanceolate,  with  gradually  attenuated 
apices.  KSA.  p.  889.  Switzerland. 
1-240".     Perhaps  a  Tryblionella  ? 

S.  ?  ornata  (K.).  —  Elongate,  pestle- 
shaped,  truncate  at  each  end,  with  obtuse 
angles,  longitudinally  dividuate,  and  or- 
namented with  minute  puncta  disposed 
in  decussating  lines.  KB.  t.  3.  f.  54. 
Marine.  Genoa.  Length  1-280";  breadth 
1-960".  Kiitzing's  figure  is  linear-oblong 
with  truncate  ends,  and  seems  to  repre- 
sent the  front  view,  in  which  the  striated 
lateral  portions  approach  so  closely  at 
the  centre  that  the  smooth  median  por- 
tion is  visible  only  near  the  ends.  Surely 
this  is  not  a  Smirella  ? 

S.  ?  Amphihola  (E.).  —  Broadly  linear, 
with  cuneate,  subacute  ends,  and  15  striae 
in  1-200" ;  front  view  with  obtuse  ends. 
ERBA.  1854,  p.  271.  Kurdistan.  1-324". 
Has  the  general  form  of  Tryhlionella 
Reyiila.  Ehrenberg  remarks  that  he  is 
not  sure  to  what  genus  this  belongs ;  he 
has  sometimes  fancied  there  was  an  um- 
bilicus, as  in  Pinnularia,  but  its  equal 
transverse  striae  on  each  side  render  its 
form  singular. 

S.  Sicula  (E.).  —  Smooth,  broadly  na- 
vicidar,  with  subacute  ends  and  longi- 
tudinal marginal  lines.  EM.  pi.  22.  f.  58. 
Fossil.     SicUy.     1-528". 


S.  Uolepta  (E.). — Styliform,  fom'  times 
as  long  as  broad,  with  obtuse  ends  and 
no  median  line ;  the  narrow  margin  finely 
striated.  KSA.  p.  36.  Maritime.  India. 
1-360". 

_  S.  ?  linea  (E.). — Bacillar,  stout,  one 
side  cuneate  at  each  end,  the  other 
rounded,  finely  transversely  striated 
throughout.  ERBA.  1843,  p.*  271.  Ne- 
therlands.    1-240". 

S.  Stylus  (E.). — Large,  stjdiform  and 
narrow,  quadrangular ;  one  end  more 
obtuse  than  the  other,  but  neither  acute ; 
costa  54  in  1-144".  ERBA.  1843,  p.  271. 
Near  Weimar.     1-144". 

S.  rhopala,  EM.  pi.  33. 1.  f.  19.  Egypt. 
Elirenberg's  figures  show  the  front  view 
large,  longly  cmieate  with  rounded  ends, 
and  numerous  fine  transverse  striae  at 
each  side,  separated  by  a  narrow  smooth 
median  portion  with  two  puncta  at  each 
end. 

S.  aspera  (E.). — Large,  with  four  or 
five  loosely  disposed  costae  in  1-1152", 
with  rough  crests.  KSA.  p.  39.  Volcanic 
earth,  Hochsimmer  on  the  Rhine.  This 
species,  named  from  a  fragment,  Ehren- 
berg states  is  perhaps  a  Campylodiscus. 

S.  Australis  (E.).  —  A  fragment  of  a 
linear  species  with  six,  straight  trans- 
verse striae  in  1-1200".  Africa.  Another 
species  constituted  by  Ehrenberg's  ob- 
jectionable practice  of  naming  isolated 
fragments. 

S.?  lmnprophylla(E.),  S.  Uralensis(E.)^ 
Ural  Mountains;  S.  Sibirica  (E.),  Sibe- 
ria ;  S.  ?  curimla  (E. ),  India,  Mexico ;  S. 
Stella  (E.),  Maritime  :  India,  Africa  ;  S. 
Nicobarica  (E.),  Nicobar;  S.  compta  (E.), 
Eo-^^t ;  S.  Zambeze  (E.),  River  Zambeze ; 
S^Platalea  (E.),  Senegal;  S.  Cafra  (E.), 
S.  Capensis  (E.),  S.  clathrata  (E.),  Cape 
of  Good  Hope ;  S.  Falklandica  (E.),  S. 
Meluinensis(K.),S.Insidani7n  (E.),  Falk- 
land Islands;  S.  Araucania  (E.),  Arau- 
cania;  S.  ampMcentra  (E.),  S.  holosticha 
(E.),  S.  insecta  (E.),  S.  leptotera  (E.), 
S.  Polyodon  (E.),  Mexico. 


Genus  CAMPYLODISCUS  (E.,  Men.).— Valves  equidistant,  frustules  soli- 
tary, disciform ;  disk  tortuous  or  saddle-shaped,  rotimdato- elliptic,  costate, 
costae  mostly  radiate.  Camjjylodiscus  has  the  lateral  surfaces  still  more 
developed  than  they  are  in  the  Melosireae,  whilst  the  central  or  interstitial 
portion  is  reduced  to  a  narrow  ring, — a  circumstance  which  renders  it  very 
difficult  to  obtain  a  satisfactory  front  view.  In  these  respects  it  approaches 
the  Coscinodisceae.  Kiitzing  referred  to  Surirella  several  species  now  placed 
in  this  genus.  Meneghini  suggested  their  removal  to  Campylodiscus,  in  these 
terms — ^'  One  really  is  at  a  loss  to  find  the  motive  that  could  induce  Kiitzing 
to  separate  this  generically  from  Campylodiscus  ; "  and  Professor  Smith  has, 


OF  THE  SrRIEELLEiE. 


799 


we  consider  judiciously,  adopted  that  suggestion.  ^'The  species  included 
under  this  genus  may  all  be  recognized  by  the  characteristic  bend  or  con- 
tortion of  their  surfaces." — Sm.  Cocconeis  differs  in  its  small  size  and  cen- 
tral nodule. 


*  Disc  circular,  or  tiearlyso,  iciih  a  single 
series  of  marginal  costce, 

t  Costae  all  radiant,  forming  a  mai'ginal 
circle. 

Campyxodiscus  Horologiimi  (Wil- 
liamson).— Disc  nearly  flat,  with  a  mar- 
ginal circle  of  numerous  (about  50)  equal, 
radiating  costee,  having  a  circle  of  close, 
very  short  and  flue  strise  at  its  inner,  and 
another  at  its  outer  edge,  and  enclosing 
a  large,  central,  orbicular,  smooth  space. 
SBD.  pi.  6.  f  51.  Marine.  Scotland. 
The  costae  are  proportionally  shorter  in 
this  large  species  than  in  most  others, 
and  occupy  about  one-third  of  the  radius. 

C.  limhatus  (Breb.). — Disc  with  a  mar- 
ginal circle  of  short  costae,  continued  by 
an  inner  fainter  circle  of  moniliform  lines, 
gradually  lost  in  an  indefinite,  smooth 
central  space.  BD.  p.  12.  f  1;  GDC.  p.  32, 
pi.  3.  f  55.  Marine.  France,  Scotland. 
"  Distinguished  from  C.  Horologium  by 
its  finer  costas  and  granulated  disc," 
Breb.  "  Gestae  broad,  transversely  sul- 
cate,  so  as  to  appear  on  close  inspection 
almost  moniliform.  Within  this  mar- 
ginal band  is  another  fainter  band,  which 
looks  almost  like  the  reflection  in  a  mir- 
ror of  the  first,  except  that  the  bars  are 
more  directly  moniliform,"  Greg.  This 
species  might  be  placed  with  almost  equal 
propriety  in  the  section  with  double  series 
of  costae. 

C.  imperialis  (Grev.).  —  Costae  3  in 
•001",  fonning  a  mag-nificent  band,  ac- 
companied at  base  by  short  bifid  seg- 
ments ;  central  area  broadly  elliptical, 
furnished  Avith  narrow,  transverse,  mo- 
niliform striae,  inteiTupted  by  a  median 
blank  line.  Gr  TMS.  ^^ii.  p.  30,  pi.  1. 
f.  3.  New  Providence.  In  general  ap- 
pearance resembles  C.  limhatus,  Breb. 
but  differs  materially  from  that  Diatom 
on  a  closer  examination.     Grev. 

C.  Kittonianus  (Gr.).  —  Costae  elon- 
gated, transversely  striated  for  two-thirds 
of  their  length.  Gr_  TMS.  viii.  p.  32, 
pi.  1.  f.  7.  West  Indies.  Central  space 
famished  with  a  median  bar,  as  in  C.  no- 
tatns,  only  less  conspicuous,  Grev. 

C.  stellatus  (Gr.).  —  Valve  orbicidar, 
with  a  narrow  marginal  band  of  close, 
short  costae,  an  inner  circle  of  dotted 
lines,  and  a  central  space  marked  with 
irregular  radiating  lines.      Gr  MJ.  vii. 


p.  157,  pi.  7.  f.  3.  Califomian  guano. 
Costae  10  in  -001". 

C.  racliosus  (F..).  —  Disc  subcircular, 
small,  with  smooth  or  obscurely  punctate 
centre,  and  border  of  about  seventy 
closelj'-set,  radiating  costae.  KSA.  t.  28. 
f  12.  Fossil.  Vera  Cruz.  Upper  Pe- 
ruvian guano.  We  have  noticed  a  Cam- 
pylodiscus  in  Bolivian  guano,  and  sup- 
posed it  to  be  this  species.  The  costae 
are  numerous,  radiating,  and  unequal, 
enclosing  a  quadrilateral,  obsoletely 
punctate  central  space,  divided  by  a 
median  hyaline  line,  and  having  at  its 
angles  3-4  converging  costae. 

C.  vulcanius  (E.). — Disc  large,  sub- 
orbicidar,  flexuose,  with  about  42  mar- 
ginal ravs,  and  smooth  centre.  KSA. 
p.  33.     Peru. 

C.  hicruciatus  (Greg.). — Disc  circidar, 
with  a  square  median  space  occupied  by 
crossed  striae,  and  prolonged  to  margin 
by  four  pairs  of  tapering,  transversely 
striate  processes  in  a  crucial  manner,  each 
inten-al  with  four  strong  radiant  costae. 
Greg  MT.  v.  p.  78,  pi.  1.  f  42.  Marine. 
Glenshira,  Scotland.  A  very  peculiar 
species,  but  difficult  to  describe.  The 
square  centre  is  lattice-like,  and  itself 
obscm-ely  subdivided  into  smaller  qua- 
drate portions ;  from  it  proceed  to  the 
margin,  in  a  crucial  manner,  foiu'  pairs 
of  conical  prolongations;  the  intervals 
between  the  pairs  are  occupied  by  strong 
rays,  which,  together  with  the  striated 
prolongations,  are  connected  within  the 
margin  in  a  scolloped  manner. 

2 1  Disc  more  or  less  evidently  divided 
into  lateral  portions  by  a  median  line 
or  band ;  costae  imperfectly  radiant. 

C.  Hibernicus  (E.). — Disc  tortuous, 
with  numerous  (30  to  40)  continuous, 
imperfectly-radiant  costae,  enclosing  an 
irregularly  shaped,  minutely  punctated 
central  space.  EM.  pi.  15  a.  f.  9.  =  C.  cos- 
tatiis,  SBD.  i.  pi.  6.  f.52.  Aquatic.  Britain. 
(jY.  38.)  The  costae  are  loosely  disposed 
(4  in  1-1152"),  slightly  rough  fi-om  mi- 
nute granides,  and  extend  in  length  about 
half  the  radius.  Their  radiant  arrange- 
ment is  somewhat  imperfect,  from  the 
convergence  of  two  or  more  at  each  end. 
IVIi'.  Norman  has  gathered  this  species 
very  pure  near  Hidl. 

C.  Noricus  (E.).  —  Disc  suborbicidar, 


800 


SYSTEMATIC  HISTORY  OF  THE  II^PUSOEIA. 


tortuous,  gi'adually  smooth  in  the  cen- 
tre ;  costse  numerous,  continuous,  their 
crest  acute.  KSA.  p.  33.  Aquatic. 
Asia  5  Salzberg.  Fossil  at  San  Fiore. 
Kays  7  in  1-1152".     B.  432". 

C.  Kiltzmgu(B,). — Disc  saddle-shaped, 
broadly  margined,  marked  with  about 
50  transverse,  continuous,  cm*ved  sulci. 
B.  in  Proc.  Acad.  Phil.  1853.  Philippine 
Islands. 

C.  Ralfsii  (S.). — Disc  small,  subcir- 
cular,  bent;  costae  transverse,  reaching 
the  median  line.  SBD.  i.  p.  30,  pi.  30. 
f.  257.  Marine.  Britain.  The  costse  of 
one  side  are  divided  from  those  of  the 
other  by  a  longitudinal  median  line. 

C.  Nonncmicus  (Gr.). — Costae  3  to  4  in 
•001",  imperfectly  radiant,  passing  across 
a  linear-oblong  central  depression  to  the 
narrow  median  blank  line.  G-r  TMS. 
viii.  p.  29,  pi.  1.  f.  1.     West  Indies. 

C.  notatiis  (Gr.).  —  Costse  numerous, 
about  12  in  -001",  in  length  more  than 
half  the  radius  ;  central  space  oval,  with 
a  median  thick  bar  dilated  at  each  end. 
Gr  TMS.  viii.  p.  31,  pi.  1.  f.  4.  Shell- 
cleanings.  Distinguished  by  the  mark- 
ings of  the  centre,  which  Mr.  Norman 
aptly  compares  to  the  figure  of  a  dumb- 
bell, Gr. 

C.  clecorus  (Breb.). — Disc  circular,  bent, 
with  a  simple  series  of  long,  arcuate  costae, 
and  a  smooth,  narrow-lanceolate  median 
space.  BDC.  p.  13.  f.  2.  =  C.  Ralfsii? 
GDC.  p.  30,  pi.  3.  f.  52.  Marine.  France, 
Britain.  "  This  species  is  very  elegant. 
Its  costse  are,  with  the  exception  of 
one  or  two  central,  all  curved  towards 
the  ends,"  Breb.  The  following  re- 
marks are  from  Dr.  Gregory's  paper : — 
"  I  have  referred  it  to  C.  Ralfsii,  S.,  al- 
though it  is  much  larger  than  the  form 
figured  by  him,  and  although  there  are 
other  differences.  Thus  in  C.  Ralfsii  the 
canaliculi  reach  the  median  line,  and  the 
row  of  heads  or  expansions  lie  some  di- 
stance from  the  margin.  But  these  dif- 
ferences cannot  be  regarded  as  specific." 

C.  angularis  (Greg.). — Disc  suborbicu- 
lar ;  costse  very  numerous  (160  or  more) 
and  unequal,  imperfectly  radiant,  form- 
ing a  simple  marginal  band,  and  divided 
into  two  sets  by  prolongations  of  the 
large,  oval  central  smooth  space.  GDC. 
p.  30,  t.  3.  f.  53.  Loch  Fine,  Scotland. 
Named  from  the  angular  bending  back 
of  the  valves.  The  costse  are  longest  at 
the  middle  of  each  side ;  and,  as  in  C. 
decorus,  all  except  the  central  ones  are 
curved,  with  the  concavity  towards  the 
ends,  and  become  also  gradually  smaller 
on  approaching  them.     "  A  true  median 


line  is  visible,  but  is  very  delicate 

The  surface  of  the  valve,  both  above  and 
below — that  is,  near  both  ends  of  the 
median  line — is  suddenly  bent  back,  so 
as  to  fomi  an  angle  with  the  rest  of  the 
valve.  On  the  surface  thus  bent,  short 
lines  appear  between  the  costse,"  Greg. 
Distinguished  from  C.  decorus  by  its  more 
numerous  costse,  oval  central  space,  and 
extensions  of  the  latter  separating  the 
costse  into  two  sets. 

C.  Hodgsonii  (S.). — ^Disc  subcircular, 
bent,  with  a  marginal  series  of  very  nu- 
merous (100  or  upwards)  imperfectly- 
radiating  costse ;  the  central  space  with 
transverse  rows  of  dots  divided  by  a 
narrow  median  smooth  line.  SBD.  i.  p. 
29,  pi.  6.  f.  53.  Marine.  Britain.  ^^The 
smooth  median  line  is  formed  by  a  ridge 
and  two  continuous  furrows  passing 
across  the  valve,"  Smith.  The  costse 
near  the  ends  converge.  Mr.  Boper  finds 
the  dots  vary  greatly  in  number,  distinct- 
ness, and  arrangement,  especially  in  the 
larger  specimens,  and  on  this  account 
considers  C.  eximius  not  distinct  from  it. 

C.  concinnus  (Grev.).  —  Costse  5  in 
•001",  radiant,  forming  a  narrow  mar- 
ginal band ;  central  area  oval,  furnished 
with  numerous  transverse  moniliform 
strise,  interrupted  by  a  median  blank  line. 
=  C,  marqinatus,  Johnst.  inMJ.  viii.  p.  13, 
pi.  1.  f.  11;  GrTMS.  viii.  p.  8,  f.  2.  Shell- 
scrapings.  New  Providence.  Californian 
guano. 

C.  eximius  (Greg.). — Disc  subcircular, 
bent ;  costse  strong,  very  numerous  (often 
150),  rather  short,  in  a  single  marginal 
subradiating  circle,  enclosing  a  large  hya- 
line space,  furnished  with  scattered  gra- 
nules and  a  median  line.  GDC.  p.  31, 
pi.  3.  f.  54.  Marine.  Loch  Fine,  Scot- 
land. The  costse  of  C.  eximius,  like  those 
of  C.  Hodgsonii,  are  rendered  imperfectly 
radiant  by  the  convergence  of  those  near 
the  end  of  the  median  line  or  raphe. 
C.  eximius  differs  from  that  species  in  its 
less  conspicuous  and  scattered  granules, 
invisible  except  when  highly  magnified. 
Mr.  Roper,  however,  may  be  right  in  re- 
garding it  as  a  variety  of  C.  Hodgsoniiy 
since  Professor  Gregory  himself  states 
that  the  granules  "  in  some  instances 
show  faint  traces  of  a  linear  arrangement 
close  to  the  marginal  band." 

2  *  Disc  circular  or  subcircular,  with  a 
double  concentric  series  of  costcB. 
C.  centralis  (Greg.). — Disc  with  about 
forty,  equal   radiating  costse,  leaving  a 
small  umbilical  space  ;  the  costse  conti- 
nuous, but  divided  into  two  series  by  a 


OF  THE  SUEIRELLEiE. 


801 


me. 
the 


shade-like  band,  the  inner  series  fainter. 
GDC.  p.  30,  pi.  3.  f.  51.  Marine.  Loch 
Fine,  Scotland.  Professor  Gregory  sup- 
poses that  the  appearance  of  a  line  which 
divides  the  costa  is  caused  by  a  ridge. 

C.  fenestratus  (Grev.).  —  Disc  circular, 
with '  marginal  radiating  costse  divided 
by  a  line  into  two  series,  the  inner  one 
fainter  and  enclosing  a  central  space 
occupied  by  four  lattice-like  sculptures 
formed  by  three  or  four  bars  crossing- 
each  other  at  right  angles.  Grev.  in  MJ. 
V.  p.  9,  pi.  3.  f.  4.  Marine.  West  Indies. 
The  continuous  costae  are  divided,  as  in 
C  centralis,  by  a  line  into  two  concentric 
series,  A  species  distinguished  by  the 
*'  four  remarkable  sculptures,  exactly  re- 
sembling square  windows  in  miniatiu'e, 
the  bars  sharp  and  slender,  and  the  panes 
actuallv  appearing  as  if  they  transmitted 
light,""  Gr. 

C.  Ecclesianus  (Grev.).  —  Disc  subcir- 
cular,  with  a  border  of  two  concentric 
series  of  very  short,  radiating  costae,  or 
narrow-oblong  cellules ;  central  space 
with  two  rows  of  transverse  broad  bars, 
separated  by  a  median  line,  from  each 
end  of  which  proceeds  a  semicircle  of  fine 
strise.  Gr.  /.  c.  p.  10,  pi.  3.  f.  5.  Mar: 
West  Indies.  ^'Similar  in  size  to 
last,  but  somewhat  more  contorted,  so 
that  when  one  portion  of  the  valve  is  in 
focus,  the  details  of  the  remaining  por- 
tion are  less  visible.  The  valve  is  con- 
cave ;  the  central  portion,  occupied  b}^  the 
two  rows  of  bars,  is  nearly  flat ;  but  on 
each  side  of  the  rows,  and  at  their  termi- 
nation, the  disc  is  inflated,  the  lateral 
inflations  being  unsculptured,  the  ter- 
minal ones  striated,"  Grev. 

C.  hicostatiis  (S.). — Disc  suborbicular, 
saddle-shaped,  with  from  twenty  to  forty 
unequal  radiating  costse,  interrupted  so 
as  to  form  two  concentric  series,  enclos- 
ing an  oblong,  smooth  central  space. 
Ro.  in  MT.  ii.  pi.  6.  f.  4 ;  SBD.  ii.  p.  88. 
Thames  ;  Norfolk.  Diam.  about  1-384". 
Costfe  distinct,  their  length,  at  sides, 
about  half  the  radius,  at  the  ends  much 
shorter.     Inner  series  less  distinct. 

C,  Cli/j^etis  (E.).  —  Disc  suborbicular; 
rays_  numerous  (40  to  100),  radiating, 
partially  interrupted,  and  forming  two 
mcomplete  concentric  series  ;  the  large 
punctated  central  space  divided  by  a 
median  smooth  line.  EM.  pi.  10. 1.  f.  1 ; 
SBD.  ii,  p.  88.  In  fresh  and  brackish 
\yaters ;  also  fossil,  Asia,  Africa,  Ame- 
rica, Europe,  England.  Original  draw- 
ings of  this  elegant  species  are  given  in 
XVII.  516,  518,  Diam,  1-576"  to  1-216". 
Costae  pimctated,  continuous  at  the  ends. 


but  interrupted  at  the  sides,  where  they 
form  two  series.  In  the  central  space 
are  two  oblong  sculptm-ed  portions,  sepa- 
rated by  the  smooth  median  line. 

C,  Remora  (E,).  —  Disc  suborbicular, 
tortuous,  with  interrupted  rays  and  a 
smooth  centre.  KSA.  p.  33.'  Marine. 
Baltic.     D.  480". 

C.  marginatm  (E.). — Disc  small,  in 
the  middle  smooth,  subscabrous,  fur- 
nished in  the  margin  with  a  double 
series  of  cellules,  the  external  fine,  the 
inner  larger,  evident,  closed  at  the  oppo- 
site ends,  open  and  radiated  in  the  mid- 
dle. KSA,  p.  33,  Maritime,  King's 
Island,  India,  Ceylon, 

C  fastuosa  (E,). — Disc  suborbicular, 
cm-ved ;  costae  subdistant,  continuous, 
divided  into  two  concentric  series,  the 
outer  inflated,  inner  shorter,  stalk-like, 
enclosing  a  finely  and  transversely  stri- 
ated central  space.  KSA,  p,  33.  =  C. 
Thureti,  BDC.  pi.  1.  f.  41 ;  C.  simulans, 
Grev  MJ.  v.  pi.  1,  f,  41,  Marine,  Asia, 
France,  England.  C.  fastuosa  is  easily  di- 
stinguished from  every  preceding  species, 
except  C.  marginatus,  by  its  finely  striate 
central  space  and  the  peculiar  appearance 
of  its  costae,  which  are  divided  by  a  line 
into  two  parts,  compared  by  Professor 
Gregory  to  a  lotus-flower  on  a  stalk.  Pro- 
fessors Kiitzing  and  Gregory  note  its  re- 
semblance to  Siirirella  fastuosa ;  we  be- 
lieve it,  however,  quite  distinct,  as,  in 
addition  to  its  circular  and  bent  form,  the 
central  striae  are  finer  and  more  numerous. 
C.  fastuosa  varies  considerably  in  size, 
and  in  the  comparative  breadth  of  the 
central  portion,  which  is  sometimes  a 
mere  line,  at  others  lanceolate,  or  even 
oval.  The  costae  are  either  interrupted 
by  the  prolongation  of  the  central  por- 
tion to  the  margin,  or  continued  all 
round. 

C.  amhiguus  (Gr.). — Disc  suborbicu- 
lar ;  costae  distant,  reaching  nearly  to  the 
centre,  partially  interrupted  at  the  mid- 
dle ;  in  the  centre  an  oblong  depression, 
within  which  is  a  short,  linear-elliptical 
blank  line,  Jamaica,  Port  Natal,  Gr 
MT.  viii,  p.  31,  pi.  1.  f,  5.=  C.  latus,  Sh 
MT.  ii,  pi.  1,  f,  13, 

C,  parvulus  (S.).  —  Disc  subcircular, 
minute ;  costae  few  (about  twelve),  in 
length  about  two-thirds  of  radius;  central 
space  obscurelv  striated.  SBD.  i.  p.  30, 
pi.  6.  f.  56.  England,  (xv.  22,  23.)  We 
have  found  this  form  generally  accom- 
panying C.  fastuosa.  Like  that  species, 
it  is  sometimes  oblong,  and  probably  is 
only  a  small  variety.  It  is  usually  much 
bent,  and  is  the  smallest  species  known. 
3f 


802 


SYSTEMATIC  HISTORY  OF  THE  IXFUSORTA. 


3  *  Disc  sitbcircnlar,  tcith  radiating  series 

of  (/ramdes   or  perforation-Iihe    dots. 
Corouia  (Uhr.). 

C.  Echeneis  (E.). — Disc  bent,  with  nu- 
merous iiTeg'ularly  radiating  series  of 
conspicuous  dots,  becoming-  fewer  and 
more  scattered  near  the  centre.  KSA. 
p.  34.  =  C.  Argus,  BMO.  ph  2.  f.  24,  25 ; 
C.  cribrosus,  SBD.  pi.  7.  f.  55.  Marine. 
America,  Europe,  England.  Diam.  1-288". 
The  costse  are  nearly  obsolete,  and  con- 
fined to  the  margin.  We  refer  C.  Argns 
to  this  species  upon  the  authority  of  our 
lamented  friend  the  late  Professor  Bailey, 

C.  dijyiost ictus  (Norman). — Disc  with 
conspicuous  marginal,  moniliform,  radi- 
ating lines,  alternate  ones  shorter,  and  a 
large,  subelliptic,  central  blank  space. 
GrevTMS.  viii.  p.  31,  pi.  1.  f.  6.  Australia. 
The  cellules  of  the  strife  are  linear-ob- 
long, and,  being  marked  longitudinally 
by  a  faint  line,  appear  doubled. 

C.  heUophilus  (E.). — Disc  small,  sub- 
orbicular,  including  in  the  broad  and 
smooth  median  area  a  quadrate  series  of 
granules,  similar  series  of  gi'anules  being 
radiately  disposed  in  the  broad  margin, 
and  in  a  double  concentric  order;  the 
external  rays  simple,  the  inner  ones 
binary.  KSA.  p.  33.  Maritime.  India, 
China.  The  proper  aiTangement  of  this 
and  the  next  species  is  doubtful. 

C.  Indicus  (E.). — Disc  large,  with  a 
subquadrate,  smooth,  median  area,  and  a 
very  broad  margin  formed  of  fine  and 
dense  radiating  series  of  granules  in  a 
double  concentric  order.  KSx\,  p.  33. 
Maritime.     King's  Island,  India. 

Var.  /3.  Concentric  rays  continuous. 
Var.  y.  Concenti'ic  rays  interrupted. 

4  *  Disc  suhcircular,  with  a  narrow,  me- 
dian, peiTious,  smooth  hand,  afid  tratis- 
vei'se  lateral  strice. 

C.  ?  striates  (E.). — Disc  with  two  series 
of  about  13  transverse  striae  on  each  side 
of  the  median  line.  EA.  iii.  pi.  7.  f.  13 ; 
KB.  pi.  28.  f.  11 ;  Bri  MJ.  vii.  p.  79,  pi.  9. 
f.  4.     Fossil.     Vera  Cruz. 


5  ^  Frustules  in  lateral  vieiv  not  circular. 

C.  Surirella  (E.). — Disc  large,  flexuose> 
oblong;  the  middle  broad  and  smooth, 
the  margin  narrower,  with  radiating 
striae.     KSA.  p.  33.    Aquatic.     Spain. 

C.  ovatus. — Disc  eiu'ved,  large,  ovate, 
obtuse,  with  nine  very  broad  pinna  in 
1-276".  =  Surirella  Clypeus,  E.  Marine. 
Baltic.     1-276". 

C.  Ehrenhergii. — Disc  flexuose,  small, 
ovato  -  elliptic ;  ends  equally  rounded ; 
margin  striated,  with  from  10  to  12  costae 
in  1-V200".z=:  Surirella  Catnpglodiscus,  E. 
Aquatic.  Italv,  Mexico,  (xv.  fs.  12, 13, 
22  &  23.) 

C.  spiralis  (K.,  S.). — Spirally  twisted, 
with  a  dotted  margin ;  laterally  elliptic, 
with  about  60  nearly  parallel  costae  ;  cen- 
tre of  disc  minutely  punctate.  SBD.  i. 
p.  29,  pi.  7,  f.  54.  Aquatic.  Europe, 
England,  (iv.  39.)  C.  spiralis  difiers  from 
C.  Ilihernicus  in  its  elliptic  and  twisted, 
not  saddle-shaped  fi'ustule.  We  doubt 
if  it  be  distinct  from  C.Jlexuosa. 

CJlexuosa  (E.). — Disc  large,  flexuose; 
costae  4  or  5  in  1-1200" .=  Sm-irella  Jlex- 
uosa,  E.  KB.  t.  28.  f.  25,  Aquatic. 
Africa,  South  America,  Mexico,  France. 
(XV.  f.  11.) 

C.  elegans  (E.). — Large,  very  broad, 
with  subacute  ends,  and  very  finely- 
punctate  siirisice.  =  Su)'i)'ella  elegatis,  E. 
KB.  t.  28.  f.  23.  Aquatic.  Germany, 
Mexico.  Costce  4  in  1-1200".  Known 
only  by  fragments. 

Q.Myodon  (E.). — Small,  rather  curved, 
laterally  elongated,  nan'ow,  with  one  end 
rounded  (the  other  unknown),  with 
small,  closely-set  costae,  giving  the  mar- 
gin a  toothed  appearance.  =  Surirella 
Myodon,  E.  KB.  t.  28.  f.  24.  Mexico, 
Japan,  Africa.  Costae  6  or  7  in  1-1200". 
Known  only  from  fr-agTiients. 

C.  Zonalis  (Ph.). — Disc  large,  gi'eatly 
deflected  ;  "  radii  spnmetrical  to  two 
axes ;  concentric  striation  may  be  de- 
tected, and  some  appearance  of  puncta- 
tion  on  the  outer  edge."  Found  in  cre- 
taceous, marly  deposits.  Bridlington, 
Yorkshire.     Prof.  J.  Phillips,  1845. 


Genus  CALODISCUS  (Eab.). — Discoid ;  disc  subcircular,  with  numerous 
(often  64)  ray-like  bands,  each  connected  at  the  broad,  striated  rim  with  its 
neighbours,  and  forming  tooth-like  straps ;  centre  not  striated,  clouded,  with 
a  lighter  transverse  one-branched  zone.  The  umbilical  zone  is  probably  non- 
essential, and  we  doubt  whether  this  genus  be  distinct  from  Campylodiscus. 

Calodiscus  superbus  (Rab.).  —  Disc  a  largish  clouded  umbilical  space.  Rab. 
large,  flat,  with  a  distinct  closely  striated  D.  p.  12.  t.  3.  Aquatic.  Italy,  (viii.  56.) 
rim,  and  equal  radiating  costae  enclosing 


OF  THE  STRIATELLEJE.  803 

FAMILY  YI.— STRIATELLE^. 

Filaments  compressed ;  the  central  portion  of  the  frustiile  furnished  mth 
incomplete  longitudinal  septa,  which  appear  like  stri«  or  costaB.  The  Stria- 
tellese  form  a  verv  distinct  grouj),  distinguished  from  every  other  by  having 
parallel  longitudinal  striae  or  costae  on  the  central  or  connecting  portion  of  the 
frustule.  "  The  appearance  of  longitudinal  striae  is  in  fact  produced  by 
siliceous  plates  arising  internally  from  the  margins  of  the  filament,  and  ex- 
tending towards  but  not  reaching  the  centre.  The  interior  is  thus  divided 
into  chambers,  opening  into  a  central  space.  When  viewed  laterally,  this 
central  space  resembles  a  canal,  especially  as  the  inner  edge  of  each  plate  has 
a  concave  outline  "  (Ealfs,  ANH.  xiii.).  The  striae  and  septa  are  frequently 
conterminal ;  in  some  genera  this  appearance  is  constant,  and  then  the  striae 
are  said  to  be  interrupted.  We  beheve,  however,  that  the  striae  are  really 
continuous,  although  always  more  strongly  marked  where  they  coincide  with 
the  septa,  and,  on  the  other  hand,  very  indistinct,  especially  in  a  young  state, 
when  they  are  merely  formed  by  an  internal  rib.  Prof.  Smith  adds  the 
following  explanation  : — "  The  valves  (lateral  surfaces)  are  similar  in  character 
to  those  of  the  other  Diatomaceae,  and  are  formed  dui^ing  self-division  in  the 
same  manner ;  but,  instead  of  the  usual  repetition  of  the  process  of  valve- 
formation,  we  are  here  presented  with  a  subsequent  intervalvular  development 
which,  not  confined  to  the  exterior  of  the  frustule,  projects  a  plate  of  silex 
into  its  interior,  forming  a  septum  or  partition  extending  towards,  but  not 
reaching,  the  centre  of  the  cell,  and  appearing  as  a  compressed  rim  or  annulus 
of  silex,  whose  outer  or  larger  cii'cumference  follows  the  exterior  outline  of 
the  frustule,  and  whose  inner  edge  bounds  the  free  space  which  serves  as  a 
channel  of  commimication  between  the  chambers  into  which  the  cell  is  thus 
divided.  This  process  is  either  simultaneous,  and  the  frustule  definite,  or 
successive,  and  the  frustule  indefinite.  In  the  fii\st  case  the  annuli  of  silex 
are  formed  during  the  production  of  the  valves  in  the  progress  of  seK-division, 
and  on  every  repetition  of  such  production ;  while  in  the  second  case  the 
formation  of  the  annidi  is  continued  after  the  production  of  the  valves,  and 
is  repeated  an  uncertain  number  of  times  before  the  recurrence  of  a  new 
valve-production  "  (BD.  ii.  p.  32). 

Kiitzing  divides  this  group  into  Striatelleae  and  Tabellarieae,  but  we  agree 
with  Meneghini  in  thinking  this  di\T.sion  unadvisable.  ^'Any  one,"  says  the 
latter,  "  examining  these  beings  with  diligence,  will  entirely  convince  himself 
that  the  distinction  of  the  two  orders  is  altogether  insufficient.  No  Tabellaria 
has  a  central  nodule  in  the  secondaiy  surfaces  at  all  to  be  compared  with 
that  of  the  Diatomeae  constituting  his  order  Stomaticae  in  his  first  tribe.  I 
fii^mly  believe  that  Tabellarieae  and  Striatelleae  ought  to  constitute  one  family, 
since  the  diaphragms,  which  are  considered  characteristic  of  the  second  ex- 
clusively, are  not  wanting  in  the  first"  (M.  I.  c.  p.  475). 

Genus  STRIATELLA  (Ag.,  K.).— Filament  of  few  fnistules  ;  stipes  long; 
frustules  longitudinally  striated,  laterally  lanceolate,  with  a  median  line  ; 
septa  short,  inner  ones  longest.  Marine.  The  long  stipes  and  absence  of 
transverse  striae  on  the  central  portion  best  distinguish  this  genus. 


^TmATB-Li,Aiimptmctata(Ljngb.,Ag.). 
—  Frustules  hyaline,  subquadrate,  with 
numerous  fine,  parallel,  continuous  lines ; 
stipes  longer  than  the  fi-ustule.     SBD. 

ii.  p.  37,  pi.  39.  f.  307.     Not  uncommon  ^  _  . 

in  the  autumn  on  Zosteraand  the  smaller  '  roundish  central  mass.     (iv.  40.) 

3r2 


Algse.  Filaments  minute,  pale  yellowash- 
brown,  glass-like,  and  glittering,  usually 
composed  of  few  frustules.  The  septa 
are  very  short.  The  internal  colouring 
matter   is    generally    collected    into    a 


804 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Genus  TESSELLA  (Ehr.). — Frnstiiles  broadly  tabulate,  not  concatenate, 
densely  striated  longitudinally  ;  strice  alternate,  interrupted  in  the  middle  ; 
stipes  none  ?  "It  is  impossible  to  judge  of  the  value  of  the  charactei^  that 
distinguish  it  from  Striatella  and  Hyalosira  whilst  we  do  not  know  the 
organic  importance  or  the  tnie  structiu-e  of  the  striae  "  (M.  I.  c.  p.  466). 

Tessella  interrupta  (E.). — Frustules  1  KB.  t.  18.  f.  4.  Mixed  with  Striatella 
in    front    view    sulDquadrate.      1-750".  |  ««?)?w<c^«^«,  but  less  abundant,    (viii.  5.) 


Genus  HYALOSIRA  (K.). — Eilaments  stipitate ;  frustules  quadi^ate,  septa 
alternate,  interrupted  in  the  middle,  and  united  by  \qyj  fine  lines.  "At 
first  I  was  afraid  that  I  was  led  by  want  of  skill  in  observing,  to  believe  that 
I  could  see  in  the  two  longer  species  of  this  genus  a  continuation  of  the  \itt3e 
from  one  margin  to  the  other,  instead  of  theii^  being  interrupted  and  alternat- 
ing as  they  are  figured  and  described  by  Klitzing.  Continuing  my  observations, 
I  succeeded  at  last  in  finding  one  indi\'idual  exhibiting  to  my  sight  the  alter- 
nations described  ;  hence  I  became  convinced  that  the  latter  condition  is  not 
merely  inconstant,  but  even  the  least  frequent.  The  secondary  suifaces  are 
elHptico-acutc  "  (M.  I,  c.  466). 


Hyalosira  minntissima  (K.).  — 
Shortly  stipitate,  concatenate  ;  frustides 
very  minute,  partially  separating  in  a 
zigzag  manner.  1-5700".  KB.  t.  18. 
f.  3.  2.     Mediterranean  Sea. 

H.  delicatula  (K.). — Shortly  stipitate, 
concatenate  j  frustules  minute,  quadrate, 
partially  separating  in  a  zigzag  manner. 
1-2640".  KB.  1. 18.  f.  111.  1.  France; 
Adriatic  Sea.      (iv.  42.) 

H.  rectam/ida  (K.). — Shortly  stipitate, 
subcoucateuate,  frustides  subquadrate, 
rectauo'ular.  1-1380".  KB.  1. 18.  f  3.  3. 
Adriatic  Sea  (xiv.  23).  Frustides  larger 
than  in  the  preceding  species. 

H.  ohtusanf/ida  (K.). — Longly  stipi- 
tate, ribbon-like  or  subconcatenate;  frus- 
tules quadrate,  with  obtuse  angles. 
1-1440".   Adriatic  Sea.  (xiv.  29.)  Frus- 


tules larger  than  in  the  first  two  species. 

H,  punctata  (Bailey). — Frustides  large, 
united  in  long  chains,  rectangular,  sub- 
quadrate,  transversely  and  uuinter- 
ruptedl}'  vittate,  alternate  vittie  granu- 
late in  the  middle  of  the  frustide,  the 
others  furnished  with  a  series  of  con- 
spicuous pimcta.     1853.     Tahiti. 

II.  Beswickii  (Kormox).,  MSS.). — Septa 
continued  across  the  filament  as  curved 
inteiTiipted  costje ;  valves  oblong,  with 
strongly  inflated  centre  and  rounded 
ends ;  stride  coarse,  30  in  -001".  New 
Zealand.  On  Alg?e  from  Joseph  Bes- 
■wdck,  Esq.  Frustules  quadrate  ;  valves 
sometimes  with  siibcapitate  apices.  [We 
are  indebted  to  Mr.  Norman  for  the  de- 
scription of  this  species.] 


Genus  RHABDONEMA  (K.).— Filaments  elongated,  shortly  stipitate; 
longitudinal  striae  uninterrupted,  connected  by  series  of  transverse  striae ; 
lateral  siufaces  having  transverse  striae  and  a  median  longitudinal  line.  From 
the  comparatively  large  size  of  the  frustules  in  Rhabdonema,  greater  facihty 
is  afi'orded  for  examining  their  stnicture.  The  longitudinal  striae  or  ribs 
(annuli,  Sm.)  are  continuous,  parallel,  mostly  equidistant,  and  connected  by 
a  series  of  transverse  striae,  so  that,  in  fact,  the  structure  has  a  latticed 
appearance. 


Rhabdonema  minutum  (K.). — Septa 
marginal,  alternate ;  lateral  valves  ob- 
long or  spindle-shaped,  inflated  at  the 
middle,  transversely  striated  throughout, 
SBD.  ii.  p.  35,  pi.  38.  f  306.  =  Tessella 
Catena,  Ralfs,  /.  c.  xii.  (not  E,).  Europe. 
1- 1200".  Smaller  than  R.  arcuatum,  from 
which  it  differs  in  the  inflated  or  gibbous 
centre  of  its  lateral  valves,    (iv.  41. ) 


R.  arcuatum  (Lyngb.,  K.).  —  Septa 
marginal,  opposite  ;  lateral  valves  oblong 
or  linear-elliptic,  the  transverse  striae 
absent  near  their  ends.  SBD.  ii.  p.  34, 
pi.  38.  f  305.  =  Striatella  arcuata,  Ag., 
E. ;  Tessella  Catena,  E.  Common,  (x. 
203,  204.)  Differs  fi-oni  B.  minutum 
in  the  form  of  its  lateral  valves,  and  by 
the  absence  of  striae  near  the  end?  :   tli9 


OF  THE  STRIATELLE.E. 


805 


series  of  striae  in  the  front  view  are  also 
more  conspicuous.  Leng-tli  of  frustule 
1-570"  to  1-200". 

E.  Aclnaticum  (K.). — Frustules  with 
four  series  of  septa  (two  marginal  and 
two  median,  the  latter  shortest  at  one 
lateral  margin,  and  gradually  longer  as 
they  approach  the  other).  SBD.  ii.  p.  35. 
pi.  38.  f.  305.  Common,  especially  from 
deep  water.  On  Alg?e,  which  are  sold 
as  "  Corsican  moss."  (xiii.  27.)  1-480" 
to  1-168".  Easily  distinguished  by  the 
median  series  of  septa,  which,  more  con- 
spicuous than  the  marginal  ones,  are 
usually  more  or  less  curved  or  oblique, 
and  do  not  coincide  with  the  ribs,  but 
cross  the  series  of  striae  ;  they  also  gra- 
dually increase  in  length  from  one  lateral 
margin  to  the  other,  leaving  a  fimnel- 


shaped  median  space. 

li.  Crozieri  (E.).  —  Lateral  valves 
turgid ;  apices  obtuse,  shortly  attenu- 
ated ;  the  perforated  dissepiments  (or 
spurious  joints)  striated,  varying  in 
number.  =  Striatella  Crozieri,  'ERBA. 
1853,  p.  529.  Assistance  Bav.  Stria) 
18  in  1-1152".    (iv.  43.) 

Species  knoivn  to  tis  only  by  name. 

R.  mirificum  (8.). — ^'A  magnificent 
species,  with  filaments  occasionally  reach- 
ing -0086"  in  Avidth,  and  with  alternate 
and  cribrose  septa.  Septa  Avith  several 
(3  to  12)  irregular  perforations."  SBD. 
ii.  p.  35.  Mauritius  and  Ceylon.  Arnott, 
JMS.  vi.  p.  92  ;  BrightAv.  JMS.  ^-ii.  pi.  9. 
f.  11.     (Till.  12.) 


GeniLs  STYLOBIBLIUM  (E.).— Erastules  cyHndrical,  multivalved,  not 
concatenated,  valves  in  a  simple  straight  series,  like  the  leaves  of  a  closed 
book,  with  a  large  median  canal,  entire  (not  perforated)  at  the  ends  ;  sculp- 
tured ;  tube  smooth.  Fossil.  Stylobiblinm  approaches  nearest  to  Biblarium 
and  Tetracyclus ;  but  the  frustules  in  the  lateral  view  are  orbicular — a  cha- 
racter not  met  with  in  the  other  genera  of  this  family.  The  species  are 
fossil,  and  occur  only  in  a  fragmentary  state. 

Stylobiblium  Clypeus  (E.). — Lateral  |  blank  band.      EM.   pi.    33.    12.   f.   30. 


view  with  from  15  to  20  short,  radiant 
marginal  lines,  and  3  or  4  pervious,  trans- 
verse median  ones,  frustules  in  the  front 
view  \x\ih  about  34  laminse  or  annuli. 
EM.  pi.  33.  12.  f.  28,  2^.  =  Biblarium 
Clypeus,  E.  Oregon  and  Siberia.  Dia- 
meter 1-792".    (iv.  45.) 

S.  ilii'isum  (E.). — Disc  large,  its  centre 
vAWx  about  10  transverse  parallel  lines, 
not  reaching  the  margin,  and  separated 
into  two  series  by  a  linear  longitudinal 


Oregon.     Diameter  1-600". 

S.  eccentricum  (E.). — Disc  with  5  to  7 
eccentric,  pervious,  curved  lines.  EM. 
pl.^33.  12.  f.  31.  Oregon.  Diameter 
1-760".  A  fragment  of  a  cylinder  con- 
tained 9  annuli.  The  costae  in  Ehren- 
berg's  figure  resemble  those  of  Tetra- 
cyclus, the  median  one  straight,  and 
those  above .  and  below  cm-ved  towards 
the  margin  in  opposite  directions  to  each 
other. 


Genus  BIBLARIUM  (E.). — Frustules  compressed,  lamelliform,  with  in- 
ternal septa ;  lateral  view  with  transverse  uninterrupted  costae,  but  T\ithout 
median  inflation.  Fossil.  All  the  species  are  fossil,  and,  although  described 
by  Ehrenberg  as  simple,  were  probably  filamentous  in  a  recent  state.  The 
forms  with  inflated  centre  we  concui^  with  Professor  Smith  in  removing  to 
Tetracyclus,  and  indeed  only  retain  the  genus  because  we  are  unable  to 
ascertain  at  present  the  proper  situation  of  the  other  species  noticed  here. 


Biblarium  compressum  (E.). — Lateral 
view  eUiptic-oblong,  with  obtuse  ends 
and  lax,  parallel  transverse  costae.  EM. 
pi.  33.  12.  f.  1.  Oregon.  1-648". 
Costae  5  to  7  in  1-1152".  Septa  28  in 
each  frustide. 

B.  elhpticum  (E.). — Lateral  view  ellip- 
tic, with  broadly  romided  ends,  and  5  to 
8  parallel  transverse  striae  in  1-1152". 
EM.  t.  33.  12.  f.  2.  Siberia  and  Oregon. 
1-1080".      Differs  from  B.   compressum 


only  in  its  more  elliptic  lateral  valves. 

B.  Lamina  (E.).  —  Lateral  valves 
broadly  linear,  with  rounded  ends, 
slightly  constricted  middle,  and  7  to  8 
parallel  transverse  striae  in  1-1152". 
EM.  pi.  33.  12.  f.  4..  Oregon.  Ehren- 
berg's  figure  shows  little  or  no  constric- 
tion. 

B.  linear e  (E.). — Lateral  valves  nar- 
rowly linear,  with  rounded  or  subacute 
ends,  and  4  to  8  parallel  transverse  striie 


806 


SYSTEMATIC  HISTOKY  OF  THE  INFrSOKiA. 


in  1-1152".  EM.  pi.  33. 12.  f.  6.  Siberia 
and  Oregon.  Ehrenberg's  figiu'es  scarcely 
differ  from  those  of  B.  Lamina,  except 
in  being  narrower. 

B.  Lancea  (E.). — Lateral  valves  lan- 
ceolate, with  subacute  apices,  and  3  to  8 
parallel  transverse  stride  m  1-1152".  EM. 
t.  33.  12.  f.  5.  Oregon.  Twenty-seven 
septa  in  each  frustule.     1-336". 

B.  Castellum  (E.). — Lateral  view  of 
central  portion  elliptic,  with  obtuse  ends, 
and  four  marginal  imdidations.  EM. 
t.  38.  2.  f.  1.  Siberia.  1-900".  Lateral 
valves  unknown,    (iv.  44.) 


B.  ?  gihhum  (E.). — Frustules  smooth, 
bacillar;  2  to  4  together,  with  straight 
centre ;  lateral  view  gibbous  at  the 
middle.  KSA.  p.  117.  Kurdistan. 
1-1152".  A  doubtful  member  of  this 
family. 

Species  hnown  to  us  only  hy  na^ne. 

B.  CMense  (Eh.  Chili.).— "  Kelated  to 
B.  compressimi,^^  EM.  p.  301. 

B.  constrictum  (E.). — Fossil.  North 
Asia. 


Genus  GOMPHOGRAMMA  (Braun). — Filaments  compressed,  continuous, 
of  few  frustules ;  septa  clavate,  alternate,  nearly  equal ;  lateral  valves  elliptic, 
furnished  with  straight  transverse  costas.  Aquatic.  Gomphogramma  agrees 
with  Tetracyclus  in  its  freshwater  habitat  and  in  the  strong  transverse  costae 
of  its  lateral  valves,  but  differs  (as  we  believe,  essentially)  by  its  clavate  septa, 
which  are  not  continued  as  costoe  across  the  central  canal.  We  are  not  suf- 
ficiently acquainted  with  the  structure  of  Biblarium  to  decide  what  may  be 
its  relation  to  that  genus  ;  but  it  is  not  improbable  that  further  investigation 
may  requii^e  their  union.  Professor  Smith  thus  contrasts  Gomphogramma 
with  Tetracyclus : — ''  In  Tetracyclus  the  valve  is  cruciform,  and  the  costae 
arched ;  in  Gomphogramma  the  valve  is  ellij)tic,  and  the  costse  direct ;  but 
these  seem  rather  to  belong  to  specific  than  generic  characters,  and  the  pro- 
priety of  uniting  these  genera  hardly  admits  of  a  question  "  (ANH.  January 
1857). 


GoMPHOGBAMMA  vnpestre  (Bravm). — 
Frustules  subquadrate,  with  fi'om  one  to 
three  septa  on  each  side  and  gland-like 
dots  along  the  junction-margins.  Braun 
in  Rab  D.  pi.  33.  t.  9.  Freiburg ;  Pyre- 
nees. This  seems  to  be  a  mountainous 
species,  and  most  probably  its  detection 


would  reward  a  search  in  our  alpme 
districts.  In  its  clavate  septa  it  some- 
what resembles  Tei-psinoe,  but  the  re- 
semblance is  merely  superficial ;  for  the 
septa  in  that  genus  are  transverse,  and 
in  this  longitudinal ;  consequently  they 
belong  to  different  groups.   (  )y   i^i,) 


Genus  TETRACYCLUS  (Ralfs).— Filaments  free,  elongated,  inflated  at 
the  centre,  striated ;  striae  continued  across  the  inflated  centre ;  septa  equal ; 
lateral  surfaces  costate.  Aquatic.  The  inflated  centre  and  strongly  costate 
lateral  surfaces  sufiiciently  characterize  this  genus.  ''  The  genus  Biblarium, 
constituted  by  Ehrenberg  in  1845,  appears  to  differ  from  the  present  merely 
in  the  solitary  character  of  its  frustules ;  and  this  character  arises  from  the 
fossil  nature  of  the  gatherings  from  which  Ehrenberg  derived  his  specimens. 
I  feel  assured  that  all  the  species  are  filamentous  in  a  living  state,  and  that 
the  greater  number  of  them  are  casual  varieties  of  Tetracyclus  lacustris" 
(SBD.  ii.  p.  37). 


Tetracyclus  lacustris  (Ralfs). —  La- 
teral view  with  the  inflations  and  ends 
roimded.  SBD.  ii.  p.  38,  pi.  39.  f.  308. 
=  Striatella  Thienemanni,  EA.  p.  136; 
Biblarium  Stella ;  B.  Glans  and  B.  spe- 
ciosum,  EM.  pi.  33 ;  B.  strumosum,  EM. 
pi.  33.  2.  f.  13.  Recent,  Britain  and 
Iceland ;  fossil,  Oregon  and  Siberia, 
(xi.  24, 25,).  The  median  inflation  seems 
variable  ;  it  is  sometimes  so  much  de- 


veloped as  to  form  a  crucial  figure  re- 
sembling the  quaterfoil  of  a  Gothic  win- 
dow, but  sometimes  merely  a  slight 
swelling,  as  in  Bihlanum  speciostwi  (E.).fyff 

T.  emarginatus  (E,,  S.).  —  Inflations 
deeply  notched,  otherwise  like  T.  lacus-- 
tris,  SBD.  ii.  p.  S8.  =  Bihlarium  emargi- 
natum,  EM,  pi.  33. 2.  f.  6.  Recent, Britain ; 
fossil,  Siberia  and  Mexico. 

T.  elegans  (E.). — Inflations  acute.  = 


OF  THE  STEIATELLE.li;. 


807 


Bihlarium    elegans,   EM.    t.  33.  2. 
Fossil.    Siberia.     Elirenberg's  figure  of 
tliis    species    differs    from    T.  Rhombus 
merely  in  its  more  developed  inflation. 

T,  ithomhm  (E.). — Lateral  view  rhom- 
boid, with  subacute  angles.  =  Bihlarium 
Rhombus,  EM.  pi.  33.     Fossil.     Siberia 


f.  4.     and  Oregon, 

T.  ?  Crux  (E.).  —  Lateral  view  cruci- 
form, with  transverse  parallel  strice  and 
a  median  &\it\\YQ.  =  Bihlarium  Crux,  EM. 
pi.  33.  2.  f.  3.  Siberia.  Strije  18  in 
1-1152".  A  doubtful  member  of  this 
genus. 


Genus  TABELLAEIA  (E.). — Frustules  quadrangular,  united  into  a  fila- 
ment, at  length  partially  separating  and  forming  a  zigzag  chain ;  septa  equal, 
straight ;  lateral  surfaces  inflated  at  ends  and  middle.  Aquatic.  Tabellaria 
differs  from  the  other  genera  of  this  family  by  having  three  inflations  of  the 
latei^  surfaces. 


Tabellaria  Jlocculosa  (Roth,  K.), —  i 
Joints   subquadrate,  with   from  3  to  7  ! 
attenuate  septa  from  each  margin ;  la-  ; 
teral  view  with  three  nearly  equal  infla-  | 
tions ;  the  intennediate  portions  linear.  | 
SBD.  ii.  p.  4o,  pi.  43.  f.  ^IQ.^Bacillaria  ' 
taheUaris,  EI.  p.  WlQ.=Navicula  trinoclis 
in  part,  E.  =  Tabellaria  vulgaris^  E.  Com- 
mon,    (xin.  29.)      Best  distinguished 
from  T.  fenestrata  by  its  less  elongated 
frustules    and    more    numerous    septa, 
which  usually  alternate  with  those  fi'om 
the  other  margin.   We  believe,  however, 
that  each  complete  septum  has  an  oppo- 
site one  which  is  generally  rudimentary, 
though  sometimes  more  developed  and 
conspicuous.     1-860"  to  1-480". 

T.  ^•ew^mosa  (K.).  —  Frustules  as  in 
T.  Jlocculosa,  but  the  central  inflation  of 
the  lateral  view  much  larger  than  the 
terminal  ones.  ItB.  t.  30.  f.  74.  =  T.  bi- 
ceps, EM.  several  figm-es.  (xiii.  26.) 
Common.  1-960".  Professor  Smith 
unites  this  to  T.  Jlocculosa,  and,  as  we 
believe,  justly,  since  intermediate  forms 
are  not  uncommon, 

T.  Gastrum  (E.). — Very  small ;  lateral 
view  with  a  subglobose  median  inflation 
and  somewhat  narrower  capitate  apices. 
KSA.  p.  119.     Fossil.     Labrador. 

T.  robusta  (E.). — Thick,  three  times 
as  long  as  broad,  with  broad  gibbous 
.centre  and  large  subacute  terminal 
capitula.  EM.  pi.  33.  f.  15.  Fossil. 
America.  1-864".  Probably  another 
variety  of  T.  Jlocculosa. 


T.  amphilepta,  EM.  pi.  3. 4.  f.32.  Fossil. 
Boston,  Ehrenberg's  figure  shows  the 
lateral  view  with  inflated  centre,  as  in 
T.  Jlocculosa ',  but  the  extremities  are  not 
dilated. 

T.  twclosa  (E.).  —  Small,  slender,  no- 
dose ;  nodules  five,  the  median  one  rather 
largest,  those  adjoining  oblong.  EM. 
several  figures.  Siberia.  Lough  Momiie 
deposit,  &c.  Ehrenberg's  figm-es  are 
elongated,  with  four  constrictions,  and 
consequently  five  inflations,  of  which  the 
median  and  terminal  are  suborbicular 
and  the  intermediate  oblong.  '^  Akin  to 
Grammatophora  undulata  "  (E.). 

T.  fenestrata  (L^TQg.,  K.). — Front  view 
linear,  with  two  opposite  septa  from  each 
end ;  lateral  view  wdth  three  nearl}^  equal 
inflations  and  linear  connectino^  portions. 
KB.  t.  17.  f.  22.  =  Tahellarm  trinodis, 
EM.  many  figm-es.  Common.  1-600" 
to  1-280", 

Species  doubtful,  or  known  to  us  only  by 
name. 

T.  amphicephala  (E.).  —  Very  small, 
with  strongly  inflated  centre  and  capi- 
tate apices.  KSxA..  p.  119.  Fossil.  San 
Fiore.  1-1728".  Scarcely  distinct  from 
T.  ventricosa. 

T.  p>laty stoma  (E.),  Sandwich  Islands ; 
T.  rhabdosoma  (E.),  Asia ;  T.  pinmdaria 
(E.),  Asia;  T,  clavata  (E.),  Northern 
Asia;  T.  undulata  (E.),  Northern  Asia; 
T.  eurocephala  (E.),  Persia;  T.  Semen 
(E.),  India;  T.  Bacillum  (E.). 


Genus  GEAStOIATOPHORA  (E.),— Frustules  forming  a  filament,  at  length 
partially  separating  and  becoming  a  zigzag  chain ;  septa  in  pairs,  opposite, 
generally  curved;  lateral  view  oblong-lanceolate,  not  inflated.  Gramma- 
tophora is  easily  distinguished  from  all  the  other  genera  by  its  strise  having 
commonly  a  cui've  outwards  near  the  base ;  and  when  this  curve  is  wanting 
it  may  be  known  from  Tabellaria  by  the  absence  of  inflation.  Although 
Kiitzing  describes  several  species  of  this  genus  as  smooth,  yet  Tve  believe  that 
all  the  species  are  striated;   and  notwithstanding  we  have  admitted  this 


808 


STSTE.MATIC  HISTORY  OF  THE  INFUSOEIA. 


character  into  some  of  the  definitions, 
strige  are  more  distinct  and  more  easily 

*  Lateral  view  obIo?ig  or  lanceolate, 
sometimes  sliyhtly  constricted  beneath 
the  apices. 

t  Septa  straight  or  fumiel-shaped. 

Grammatophora  stricta  (E.).  — 
Large,  wath  straight,  parallel  septa ; 
lateral  view  lanceolate.  B^B.  t.  29.  f.  76. 
Asia,  Africa,  America. 

G.parallela,  EM.  pi.  21.  f.  26.  We 
know  not  how  this  form  diiiers  from 
G.  stricta,  except  that  the  figures  of  the 
lateral  valves  exhibit  more  rounded 
apices. 

G.  Tahellaria,  EM.  pi.  18.  f.  89,  90. 
Fossil.  Virgmia.  In  Elirenberg's  figures 
the  front  view  has  the  septa  slightl}^ 
cm'ved  and  dilated  inwards  (fimnel- 
shaped)  ;  lateral  view  lanceolate,  with  a 
large  central  canal. 

2 1  Septa  with  a  semicircular  curv-e  near 
the  marginal  ends ;  otherwise  straight. 

G.  marina  (Ljug.,  K.).  —  Septa  with 
a  single  curvatm-e ;  lateral  view  linear- 
obloug,  gradually  tapering  into  the  ob- 
tuse apices.  KB.  t.  17.  f.  24.  =  Diatotna 
tcenicefonne,  D.  marinum  (Lpig.),  and 
D.  latruncalarium  (Ag.),  D.  hrachy- 
ffonium  (Carm.),  Bacillaria  CleopatrcB 
(E.).,  B.  Adriatica  and  B.  Meneghina 
(Lobarzewsky),  Grammatophora  oce- 
anica.  Everywhere.  Common,  often 
forming  long  chains,  (iv.  47 ;  xi.  52,  53.) 
The  synonyms  are  adopted  from  Kiitzing, 
and  probably  some  of  them  belong  to 
other  species.  The  frustules  are  of  very 
variable  length,  sometimes  nearly  square, 
sometimes  many  times  longer  than  broad. 
Connecting  hinge  slender. 

G.  tropica  (K.). — Laro-e,  ssAW  striated 
margin ;  septa  with  a  single  curvature ; 
lateral  view  linear,  \\dth  rounded  apices. 
KB.  t.  30.  f  71.  Cape  of  Good  Hope. 
1-600"  to  1-156' 
tumid. 

G.  gihha  (E.). — Large,  striated;  septa 
curved  at  outer  end,  otherwise  straight ; 
lateral  view  linear,  with  slightly  in- 
flated centre  and  rounded  ends.  KB. 
t.  29.  f  77.     Cuba.     (xi.  48,  49.) 

G.  Mexicana  (E.). — Large ;  septa  with 
a  single  cm'vature ;  lateral  view  con- 
stricted beneath  the  rounded  apices.  KB. 
t.  18.  f.  1-6.  Em-ope,  America.  Con- 
necting hinge  tumid. 

G.  gibberula  (K.).  —  Margin  striated  ; 
septa  once  curved ;  lateral  view  lanceo- 


Connecting   hinge 


we  use  it  merely  to  indicate  that  the 
detected. 

late,  with  tumid  centre  and  obtuse  apices. 
KB.  t.  30.  f.  81.  Naples.  1-450".  Con- 
necting hinge  slender.  Difters  from  G. 
Mexicana  in  its  distinctly  striated  mar- 
gin and  more  lanceolate  lateral  view. 

G.  macilenta  (S.). — Frustides  often 
cmved;  septa  as  in  G.  marina-,  lateral 
valve  linear,  slightl}'  inflated  at  centre 
and  extremities ;  striae  60  in  -001".  SBD. 
ii.  p.  43,  pi.  61.  f  382.  Britain ;  Levant. 
"  The  front  view  in  this  species  is  always 
narrower  in  proportion  to  its  length  than 
in  G.  marina.  The  strise  are  also  far 
more  numerous ;  and  the  frustule,  espe- 
cially in  the  larger  specimens,  shows  a 
decided  tendency  to  assmne  a  cm'ved 
form." 

3 1  Septa  Innately  curved,  both  ends 
hooked  inwards. 

G.  hamidifera  (K.).  —  Small,  subqua- 
drate ;  septa  cmwed  throughout,  with 
their  concavities  towards  each  other. 
KB.  t.  17.  f.  23.  Common,  especially 
from  deep  water,  (xiii.  22.)  _  1-2400" 
to  1-960".  Distinguished  by  its  small 
quadrate  frustules  and  imiformly  cm*ved 
septa.  It  is  possible,  however,  that  it 
may  be  the  immature  state  of  one  of  the 
following  species. 

4t  Septa  undulate,  inner  ends  incm-ved. 

G.  angidosa  (E.).  —  Septa  hooked  in- 
wards, at  inner  end  and  near  the  margin 
of  fr-ustule  with  angular  curve  inwards. 
KB.  t.  30.  f.  79.  Atlantic  and  Pacific 
Oceans.  Perhaps  a  variet}'  of  G.  Afri- 
cana. 

G.  Africana  (E.).  —  Septa  with  three 
undida'tions,  the  inner  ends  incm'ved ; 
lateral  view  lanceolate,  obtuse.  EM. 
pi.  19.  f.  34.  Fossil,  Gran ;  recent,  not 
uncommon.     1-2300"  to  1-480". 

G.  Islandica  (E.).  —  Septa  with  three 
undulations,  cui^ed  at  the  centre ;  lateral 
view  navicular,  striated.  KSA.  p.  121. 
Iceland. 

G.  serpentina  (E.). — Large,  vnth.  stri- 
ated margin;  septa  with  several  undu- 
lations and  incurved  inner  ends ;  lateral 
valves  linear,  "wdth  attenuated  ends  and 
obtuse  apices;  connecting  hinge  thick. 
SBD.  ii.  p.  43,  pi.  42.  f  315.  =  G.  3fedi- 
terranea  (E.),  according  to  Kiitzing.  Not 
uncommon  in  sheltered  bays.  Remark- 
able for  its  seii)entine  septa,  the  number 
of  curves  seeming  to  vary  according  to 
the  length  of  the  frustule";  and  we  fear 


OF  THE  STllTATELLEJE. 


809 


that  some  of  the  allied  species  are  not 
really  distinct  from  it.  Professor  Smith 
informs  us  that,  in  this  species,  JNIr.  West 
finds  the  dots  disposed  in  quincunx,  and 
the  lines  consequently  oblique,  (iv.  48.) 
G.  anguina  (K, ).  —  Large,  smooth  ; 
septa  serpentine,  with  the  interior  end 
hooked  inwards.  KB.  t.  17.  f.  25.  At- 
lantic and  Antarctic  Oceans.  1-650"  to 
1-360".  We  see  not  how  this  differs 
from  G.  serpentina,  as  we  believe  that  no 
species  in  this  genus  is  really  smooth. 

2*  Latei'al  view  with  four  constrictions. 
G.  undulata  (E.). — Lateral  view  linear, 
with    four    constrictions    and    rounded 
ends ;   septa  in  ft'ont  view  undulated. 


KB.  t.  29.  f.  68.    Fossil,  Greece  ;  recent, 
America.     1-860". 

3  *  Lateral  view  lunate. 

Gc.  arcuata,  EM.  pi.  35  a.  23.  f.  11,  12. 
Assistance  Bay.  The  figures  represent 
the  front  ^dew  with  undulated  septa, 
and  the  lateral  one  lunate,  with  trans- 
verse lines  and  a  central  canal. 

G.  curvata,  EM.  pi.  35  a.  22.  f.  13. 
Antarctic  Ocean.  The  figure  shows  the 
lateral  view,  like  that  of  G.  arcuata  5  but 
its  central  canal  is  smaller,  and  there  are 
no  transverse  lines. 

G.  subtilissima.  —  StrisD  fine.  A  good 
test  for  high  powers. 


Genus  GEPHYRIA  (Arnott). — Frustules  attached;  front  view  with  sub- 
lamellate,  finely  striated  connecting  zone,  destitute  of  septa ;  valves  arcuate, 
dissimilar,  with  transverse  costae  internipted  by  a  longitudinal  Une.  Marine. 
We  place  Gephyria  with  the  Striatelleai  because  of  its  resemblance  to 
Eupleuria;  but  the  absence  of  septa  renders  its  proper  position  somewhat 
doubtful.  The  lower  valve  dififers  from  the  upper  one  in  having  a  smooth 
circular  space  at  each  end.  The  strongly  arched  valves  and  absence  of  septa 
distingiiish  it  from  Eupleuria.  It  differs  from  Achnanthes  by  having  no 
central  nodule. 


Gephybia  incurvata  (Ar.). — Costse  of 
valve  about  7  in  -001";  connecting  zone 
with  stout  longitudinal  costae.  Ai'  M J. 
viii.  p.  20.  =  Eujileuria  incurvata,  Ar  MJ. 
vi.  p.  90 ;  Achnanthes  costata,  Johnstone, 
M  J.  viii.  p.  20,  pi.  1.  f.  14.  South  African 


and  Patagonian  guano. 


G.  media  (Ar.). — Valves  obtuse,  with 
11  costse  in  -001".  Ar  MJ.  viii.  p.  20. 
Achnanthes  angustata,  Johnstone,  MJ. 
viii.  p.  20,  pi.  1.  f.  13.    Califomian  guano.   (l9 ,  i,j 

G.    Telfairiee    (Ai\).  —  Valves    ^^dth  ^ 

acute   cuneate   ends,   and   15  costas  in 
•001".    ArMJ.  \iii.  p.  20.     Mauritius. 


Genus  EUPLEURIA  (Arnott).  —  Frustules  united  into  short,  attached 
filaments ;  front  "^iew  annulate,  indefinite,  with  short  septa  and  beaded 
margins ;  valves  dissimilar,  costate  ;  costae  interrupted  by  a  longitudinal  line, 
those  of  lower  valve  fewer  and  central.  Marine.  Euplemia  differs  from 
Rhabdonema  by  its  dissimilar  valves,  the  transverse  costse  of  the  lower  one 
being  confined  to  the  middle — a  character  conspicuous  even  in  the  front  view, 
since  the  ends  of  the  costae  are  there  seen  as  marginal  bead-like  dots.  The 
valves  have  some  resemblance  to  those  of  Achnanthes,  but  have  no  central 
nodule  or  stauros. 

Eupleuria  pulchella  (Ar.).  —  Front  ;  oblong.  In  the  lower  valve  the  costae 
view  ^^atll  stout  longitudinal  costae  con-  |  and  longitudinal  line  are  present  only  at 
nected  by  transverse  bars,  very  short  |  the  middle  portion,  and  leave  a  large 
septa,  and  punctated  lateral  margins,  hyaline  blank  space  at  each  end.  Striae 
Ar  TMS.  vi.  p.  89.  New  Zealand  and  j  between  the  costae,  and  oblique.  /  KZTT  -  J^J 
Australia.  The  frustules,  in  the  fi-ont  |  E.  oceUata  (Ar.).  —  Front  view  with 
view,  have  the  cellulate  structure  of  j  longitudinal  lines,  fine  transverse  striae, 
Rhabdonema ;  but  the  septa  are  so  abbre-  j  and  costate  lateral  margins  ;  costae  of 
viated  as  to  seem  mere  marginal  dots,  1  ventral  margin  longer,  confined  to  the 
and  the  puncta  on  the  ventral  margin  middle,  and  divergent.  Ar  TMS.  vi.  p.  9. 
are  confined  to  the  middle.  Annuli  close,  |  New  Zealand.  In  E.  oceUata  the  frustides 
numerous ;  valves  usually  turgid  at  the  are  more  hyaline  than  in  E.  pidchelluy 
middle  and  rapidly  tapering  to  the  obtuse  and  the  longitudinal  costae  less  conspi- 
apices  (subovate),  but  sometimes  linear-    ciious,  and  not  connected  bv  transverse 


810 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


bars.  The  most  evident  distinction, 
however,  is  the  clavate  or  capitate  lines 
of  the  dorsal  and  ventral  margins,  those 
of  the  latter  being  longer,  fewer,   and 


divergent.  The  septa  seem  to  be  rudi- 
mentary, as  in  the  preceding  species. 
Valves  oblong-linear,  sometimes  cm-ved, 
with  rounded  ends. 


GeniLS  ENTOPYLA  (Ehr.). — Fmstiiles  prismatic,  compressed,  multivalved ; 
valves  contiguous,  in  a  straight,  simple  series,  like  the  leaves  of  a  book ; 
internal  ones  traversed  by  a  large  median  opening ;  outer  ones  transversely 
striated,  unequal,  one  entire  (not  perforated),  the  other  furnished  with  a  large 
pore  at  each  end.  Marine.  Entopyla,  by  its  curved  form,  approaches 
Achnanthes ;  by  its  tabulate  figure  it  is  more  akin  to  Tessella ;  but  it  comes 
nearer  to  Biblarium  than  to  any  other.  Although,  in  deference  to  the  opinion 
of  Professor  Arnott,  we  have  kept  Eupleuria  distinct  fi^om  this  genus,  we 
doubt  the  propriety  of  doing  so.  From  Ehrenberg's  comparison  of  Entojjyla 
\vith  Tessella  and  Biblarium,  and  beaiing  in  mind  his  peculiar  views,  it  is 
c\ident  that  the  "  internal  valves "  are  the  "annuli"  of  Smith,  and  the  "per- 
forations of  the  ventral  valve"  the  blank  spaces  at  each  end.  Since  the 
opening  in  the  internal  valves  is  stated  to  be  so  large  as  to  leave  only  a  thin 
margin,  the  septa  must  be  rudimentary.  Both  Entopyla  and  Eupleui^ia  seem 
therefore  to  differ  from  Khabdonema  in  their  dissimilar  valves  and  rudimen- 
tary septa,  nor  are  we  able  to  find  any  character  in  Ehrenberg's  description 
which  enables  us  to  distinguish  Entopyla  from  Eupleuria. 


Entopyla  Australis  (Ehr.). — Leaves 
(annuli)  about  16  j  transverse  costaB  of 
outer  ones  (or  valves)  32  to  more  than 
40  in    nimiber,   divided  by   a    median 


flexuose  line.  ERBA,  1818,  p.  42.  = 
Surirella  Australis,  Ehr.  1843.  Pata- 
gonian  guano. 


Genus  DIATOMELLA  (Grev.). — Frustules  quadrangular,  forming  at  first 
a  piano- compressed  filament,  at  length  separating ;  vittae  two,  interrupted 
in  the  middle  and  at  each  end.=Disiphonia,  E.  Aquatic.  Professor  Smith 
doubtfully  referred  to  Grammatophora  the  Diatom  for  which  this  genus  was 
constituted ;  but  we  consider  the  differences  pointed  out  by  Dr.  Greville  as 
sufficient,  independently  of  its  aquatic  habitat,  to  separate  it  from  that  genus. 
In  Grammatophora  the  septa  are  formed  in  the  central  or  connecting  portion, 
arise  from  the  margins  of  the  filament,  and  are  interrupted  in  the  middle.  In 
DiatomeUa  they  appear  to  us  to  arise  from  a  thickened  rib  connecting  the 
lateral  and  central  portions,  and  form  imperfect  diaphragms  with  three  open- 
ings— one  central,  the  others  marginal.  We  have  included  DiatomeUa  in  this 
family,  but,  although  Professor  Smith  states  that  its  frustules  are  annulate 
and  nearest  in  structui^e  to  Grammatophora,  we  are  not  siu-e  it  is  rightly 
placed  here ;  for  two  puncta  exist  at  each  end  of  the  frustule,  as  in  the 
Fragilariese. 

DiATOMELLA  Bolfounana  (Gr.). — La- 
teral view  linear  or  oblong,  with  rounded 
ends  and  45  fine  stri«  in  -001."  GANH. 
s.  2.  XV.  pi.  9.  fs.  10-13.  =  Grammato- 
pJiora  ?  Balfuuriana,  SBD.  ii.  p.  43,  pi. 
61.  f.  3S3.=Disiphoma  Amtralis,  EM. 


pi.  35  a.  f.  7.  South  Africa,  South  Ame- 
rica, Scotland.  Front  view  quadi*angular, 
vnth.  a  smooth  central  portion,  separated 
from  the  transversely- striated  lateral 
valves  by  the  vittae.    (iv.  51,  52.) 


FMHLY  VII.— MELOSIREJE. 

Frustules  disciform,  cylindrical,  or  globose,  simple  or  united  into  a  filament ; 
lateral  surfaces  flat  or  convex,  circular,  smooth  or  with  radiating  striae,  less 
frequently  cellulose,  granulate  or  punctate ;  front  view  with  the  central  por- 
tion usuallv  either  obsolete  or  di^•ided  by  one  or  two  central  furrows.     "  For 


OF  THE  MELOSlREJi:. 


811 


the  most  part  the  Coscinodiscese  are  related  to  this  family,  with  which  they 
have  been  hitherto  united  by  Ehrenberg  ;  but  I  have  separated  them  because 
the  shell  of  the  Coscinodisceae  often  has  divergently  arranged  bands  and  a 
cellulose  formation,  which  is  wanting  in  the  Melosirese.  Moreover  the  forms 
of  the  genus  Melosira  have  in  life  so  great  similarity  to  the  true  simple  Con- 
fervae,  that  they  may  easily  be  confounded  even  by  practical  Algologists. 
The  heating  of  a  specimen  upon  mica,  however,  distinguishes  them  so  cer- 
tainly that  we  can  never  be  in  doubt "  (Kiitzing).  The  line  of  demarkation 
between  the  Melosireae  and  Coscinodiscese  is  by  no  means  well  established ; 
generally,  discoid  forms  with  cellulose  structure  belong  to  the  latter,  and  fila- 
mentous or  smooth  species  to  the  former.  This  family,  however,  contains 
some  distinctly  cellulose  species  ;  but  they  are  distingiushed  by  their  inflated 
or  vaulted  segments  and  the  absence  of  a  central  portion. 

We  have  removed  some  genera  Kiitzing  had  placed  here,  as  we  consider 
Mr.  Brightwell  has  proved  that  they  are  more  akin  to  Chaetoceros. 

Genus  CYCLOTELLA  (Kiitz.). — Frustules  discifoim,  simple  or  binately 
conjoined  ;  central  portion  ring-like ;  valves  plane  or  slightly  convex. 
Aquatic  and  marine. =Discoplea,  Ehr.  Cydotella  differs  from  Melosira  in 
not  forming  a  filament.  The  recent  species,  according  to  Kiitzing,  are  either 
adnate  or  enclosed  in  a  shapeless  gelatinous  substance.  Some  of  the  species 
approach  closely  in  character  to  Coscinodiscus.  We  retain  Kiitzing's  name 
because  it  has  the  claim  of  priority. 

Cyclotella  operculata  (K.). — Valves  j 
depressed  in  the  centre;  strise  obscure 


very  short  ;  front  view  with  rounded 
angles.  SBD.  i.  p.  28,  pi.  5.  f.  48.  Fresh 
water.  Em-ope.  This  species  is  involved 
in  great  confusion,  and  we  confess  our 
inability  to  reduce  it.  We  have  adopted 
Professor  Smith's  views,  though  with 
much  hesitation.  Kiitzing  describes  the 
margin  as  punctated;  and  his  figm-es, 
though  varying  much  in  size,  of  the 
umbilical  portion,  show  the  margin 
closely  and  irregularly  pimctate,  whilst 
Smith  describes  them  as  striated.  Kiit- 
zing refers  here  the  Discoplea  Kiitzmgii 
(E.) ;  but  that  form,  according  to  the 
figures  in  the  ^  Microgeologie,'  is  larger, 
with  radiating  striae  reaching  to  the 
centre  of  the  disc.    (v.  53.) 

C.  rectangula  (Breb.). — Similar  to  C. 
opei'culata ;  but  the  frustules  in  the  front 
view  have  acute  angles.  Rah  D.  p.  11. 
France.  By  Kiitzing  made  a  variety  of 
C.  operciilata,  by  Smith  of  C.  Kiitzmgi- 
ana.    (v.  54.) 

C.  Scotica  (K.).  —  Frustules  adnate; 
disc  plane,  very  smooth.  KB.  t.  i.  f.  2, 
3.  =  C.  Ligustica,  K.  /.  c.  t.  1.  f  4.  On 
marine  algae.  Scotland,  &c.  We  imite 
C.  Ligustica  to  this  species,  since  Kiitzing 
makes  no  distinction  except  size,  which 
in  the  Diatomacete  is  too  variable  to  be 
made  the  onlv  specific  difterence.  D. 
1-960"  to  1-516".    (xw.  17.) 

C.  maxima  (K.). — Frustules  large,  ad- 
nate ;  disc  nearly  plane,  punctated.  K.  /.  c. 


1. 1.  f.  5.    On  Algae  in  the  Pacific.   Diam. 
1-800"  to  1-126".     Puncta  scattered. 

C.  Coscmodiscus  (E.,  K.). — Disc  small, 
irregidarly  but  densely  and  finely  granu- 
late, margin  smooth.  =  Z)wcq/:>/m  Cosci- 
nodiscus, EM.  pi.  33. 10.  f.  1,  2.  FossU. 
United  States.  Habit  of  Coscinodiscus 
ininor,  rather  turgid  on  the  sides.  D. 
1-1728". 

C.  Mammilla  (E.,  K.). — Disc  smooth, 
umbonate  in  the  centre ;  sutm-e  in  front 
view  tiunid,  produced  at  the  margins.  = 
Discoplea  Mammilla,  EM.  pi.  38.  22. 
f.  1-3.  Fossil.  Patagonia.  The  suture 
between  the  valves  is  ridge-like,  and 
consequently  projects  at  the  margins. 
Rim  of  disc  striate.     Diam.  1-1728". 

C.  umhilicata  (E.). — Disc  smooth,  with 
a  central  smooth  xnmho.  =  Discoplea  um- 
hilicata, EM.  pi.  35  B,  B.  £  9,  From 
Atlantic  deep  soundings.  Ehrenberg 
describes  this  species  as  smooth,  but 
figures  it  with  a  punctated  centre. 

C.  Americana  (E.,  K.). — Frustides  in 
front  view  turgid,  vdth  a  transverse,  tri- 
carinated  ring ;  disc  punctate  in  the 
centre.  KSA.  p.  19.  United  States. 
Diam.  1-660". 

C.  physoplea  (E.,  K.). — Disc  smooth, 

except  a  circlet  of  large  vesicular-looking 

granides  round  the  centre.  =  Discoplea 

physoplea,  EM.  pi.  33.  17.  t  8.     Fossil. 

,  Virginia.     Diam.  1-1152". 

I      0.  cojnta  (E.,  K.), — Disc  with  a  circlet 

I  of  small  striae  near  the  margin,  and  a 

crowded  central  mass  of  granules.  =  Z>?5- 


812 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


coplea  comta,  EM.  pi.  38.  1  b.  Asia, 
Africa,  &c.  Front  view  tumid  at  the 
sides.  Altliough  this  species  is  said  to 
have  a  g-raniilated  umbilicus,  none  of 
Ehrenberg's  figures  exhibit  this  cha- 
racter. 

C.  dendrochisra  (E.). — Disc  smooth, 
except  a  circlet  of  short  rays.  =  Discoplea 
dendrochmra,  E.  On  trunks  of  trees, 
Venezuela.  Frustules  small,  tumid  in 
front  view.  Diam.  of  disc  1-1920";  cen- 
tral circlet  with  about  ten  rays.  Habit 
of  C.  comta. 

C.  atmospherica  (E.).  —  Disc  with  a 
central,  rather  turgid  umbilicus,  from 
which  radiate  numerous  striae.  =  Discoplea 
atmospherica,  EM.  pi.  39.  1.  f.  17.  In 
atmospheric  dust.     Diam.  1-1008". 

C.  Sinensis  (E.). — Disc  with  a  central, 
rather  turgid,  granular  umbilicus,  from 
which  radiate  numerous  striae ;  the  stride 
separated  from  the  umbilicus  bv  a  border. 
=  Discoplea  Sinensis,  EM.  pi.  39.  l.f.  16. 
Atmospheric  dust.  China,  &c.  Diam. 
1-864".  Kays  much  closer  than  in  C. 
aUnospherica,  and  smooth,  not  rough  as 
in  that  species.  In  front  view  linear, 
with  striated  margins,     (xv.  4.) 

C.  Atlantica  (E.). — Disc  with  a  central, 
somewhat  granular  umbilicus,  from  which 
proceed  numerous  radiating  lines.  =  Dis- 
coplea Atlantica,  EM.  pi.  39.  3.^  f.  29. 
Atmospheric  dust.  Atlantic.  Smaller 
than  the  last,  and  its  umbilicus  not  cir- 
cumscribed by  a  rim ;  but  we  doubt 
whether  this  and  the  two  preceding  spe- 
cies are  sufficiently  distinct,    (xv.  3.j 

C.  Oregonica  (il.).  =  Discoplea  Oreqo- 
nica,  EM.  pi.  37.  2.  f.  3.  Oregon.  Eh- 
renberg's figui-e  represents  a  small  disc 
with  a  central  punctated  umbilicus,  from 
which  proceed  numerous  rays.  Front 
view  linear,  with  marginal  striae.  Does 
this  differ  from  C.  Sinensis  ? 

C.  venusia  (E.). — Disc  with  granulated 
umbilicus  and  numerous  smooth  rays.  = 
Discoplea  venusta,  ERBA.  1852,  p.  534. 
Alive.  .  California.  Akin  to  C.  atmo- 
spherica ;  frustules  with  the  stellate  habit 
of  Actinocyclus.  Ehrenberg  observed 
three  specimens.  In  one  the  umbilicus 
was  nearly  equal  to  a  fourth  part  of  the 
diameter  of  the  disc,  and  the  entire  sur- 
face very  nearly  smooth ;  in  another  the 
surface  was  distinctly  granulated,  and 
the  umbilicus,  having  its  margin  oblite- 
rated, was  scarcely  evident. 

C.  Astresa  (E.,  K.). — Disc  with  a  large 
punctated  centre  and  deuselv-raved  mar- 
gin. KSA.  p.  19.  =  a  HotulaiKBA.  2.  f.  4 ; 
8BD.  pi.  6.  f  50  ?  Kurdistan  ;  Ireland. 
Diam.  1-636".  It  has  the  habit  and  size  of 


Melosira  varians,  but  is  not  concatenate. 
C.  Rotida  is  a  marine  species. 

C.  Pei'uana  (E.,  K.). — Disc  with  very 
fine  rays,  reaching  to  the  centre.  =  Dis- 
coplea pertiana,  EM.  pi.  38  a.  14.  f.  6.  In 
pumice  from  Arequipa  and  Santiago, 
Peru.  Resembles  C.  Astresa.  Diam. 
1-600".  The  thickness  of  the  frustule 
equals  half  its  length.  Although  the  rays 
are  described  as  reaching  the  centre,  the 
figures  show  an  umbilical  space. 

C.  oligactis  (E.).  =  Discoplea?  oligactis, 
EM.  pi.  35  A.  9.  f.  1.  Ganges.  Ehren- 
berg's figure  shows  a  smaU  disc,  with 
striated  rim  and  irregidar  umbilical 
space,  from  which  proceed  a  few  irregu- 
lar rays. 

C.  Grceca  (E.). — Disc  plane,  inter- 
ruptedly striated  in  a  radiate  manner.  = 
Discoplea  Grceca,  E.  =  Coscinodiscus  Grce- 
cus,  KSA.  p.  125 ;  EM.  pi.  6. 2.  f.  1.  Fossil 
in  Greece.     Diam.  1-864". 

C.  antiqua  (S.). — Valves  convex;  striae 
broad,  not  reaching  the  margin.  Diam. 
•0009"  to  -0013".  SBD.  i.  p.  28,  pi.  5.  f. 
42.  Lough  Mourne  and  Peterhead  de- 
posits, &c. 

C.  picta  (E.,  K.). — Disc  plane,  broadly 
granulated  in  the  middle,  its  margin 
densely  radiated ;  rays  very  slender,  ele- 
gantly mixed  with  pairs  of  stouter  ones. 
KSA.  p.  20.  African  coast.  Disc  some- 
times large. 

C.  Rota  (E.,  K.).  —  Disc  large,  with 
numerous  (52)  equal  rays,  not  reaching 
to  the  centre  ;  surface  papillose ;  papillae 
unequal,  smallest  between  the  rays, 
largest  at  the  centve.  =  Discoplea  Rota, 
EM.  pi.  35  A.  22. 1  6.  Southern  Ocean. 
Diam.  1-192".  This  and  the  next  species 
are  distinguished  from  the  rest  by  having 
papillae  or  granides  in  the  intervals  of 
the  ravs. 

C.  Rotula  (E.,  K.).  —  Resembles  C. 
Rota,  but  is  smaller,  its  rays  fewer  in 
number  (20),  and  its  papillae  equal.  = 
Discojjlea  Rotula,  EM.  pi.  35  a.  22.  f.  7. 
Southern  Ocean.  Diam.  1-696".  As  in 
C.  Rota,  the  rays  extend  from  the  margin 
towards,  but  do  not  reach  the  centre. 

C.  denticidata  (E.,  K.). — Disc  marked 
with  straight,  parallel,  granidated  lines, 
and  its  margin  denticulate.  KSA.  p.  20. 
Bermuda.  Diam.  1-672".  In  the  character 
of  its  margin  it  resembles  Melosira  sul- 
ccda,  but  in  the  arrangement  of  its  gra- 
nules it  approaches  Coscinodiscus  lineatus. 

C.  undidata  (E.,K.). — Disc  with  radiat- 
ing lines  of  very  minute  granules,  and  an 
undulated  margin.  =  Discoplea  undidata, 
EM.  pi.  33.  18.  £  3.  Bermuda.  ]>iam. 
1-576".    Marginal  fiexures  about  fifteen. 


OF  THE  MELOSIRE^. 


813 


C.  stylorum  (Br.). — Valve  with  styli- 
fomi  rays  diverging  from  the  centre,  and 
ending  near  the  margin  with  a  large 
circidar  head;  centre  irregularly  punc- 
tate. Sierra  Leone.  Br  TMS.  viii.  p.  96, 
pi.  6.  f.  16. 

C.  ?  radiata  (Br.). — Valve  with  simple, 
strongly  marked  radii,  reaching  nearly  to 
the  centre ;  centre  smooth ;  in  front  view 
the  ends  of  the  radii  appear  as  pimcta. 
West  Indies,  Monterey.  Br.  /.  c.  p.  96, 
pi.  6.  f.  11.     As  many  as  ten  frustiiles 


have  been  found  in  union;  this  may, 
therefore,  belong  to  Melosira. 

C.  punctata  (S.). — Frustules  with  un- 
dulations ;  valves  delicately  punctate  or 
cellulate ;  cellules  radiate.  Diam.  -0008" 
to  -0015".  Fresh  water.  England.  SBD. 
ii.  p.  87.    (^^II.  13.) 

C.  Dallasiana  (S.). — Valves  with  mar- 
ginal costse  ;  centre  cellulate  ;  cellules 
irregular.  Length  of  costae  'OOOS";  Diam. 
of  valve  *022".  Brackish  water.  Eng- 
land.    SBD.  ii.  p.  87. 


Genus  ACTI^N'OGONIUM  (Ehr.).— Frustules  suborbicular,  many- angled ; 
disc  smooth,  mth  radiating  lines.  Actinogonium,  like  Liostephania,  differs 
from  the  rest  in  being;  smooth. 


Actinogonium  septenarium,  EM.  pi. 
36.  I  39.  Barbadoes.  Rays  (7)  divid- 
ing the  disc  into  compartments,  separated 
from  the  margin  by  a  regularly-undu- 


lated border.  Between  the  centre  and 
border  is  a  circlet  of  very  short  lines,  two 
in  each  compartment,    (v.  55.) 


Genus  LIOSTEPHANIA  (Ehr.). — Frustules  simple,  orbicular;  disc  smooth, 
but  with  a  crown  of  rays  encircling  a  large  smooth  central  space  or  umbi- 
licus. Liostephania  is  distinguished  by  its  disc  being  smooth,  and  having  a 
circlet  of  striae,  which  striae  do  not  reach  the  margin. 


Liostephania  Rotula  (E.).  —  Disc 
having  from  six  to  foiu-teen  simple  rays. 
EM.  pi.  36.  f  40.     Barbadoes.    (v.  57.) 

L.  comta  (E.). — Disc  with  from  six  to 
thirteen  rays,  connected  exteriorly  by  a 
circlet  of  puucta.  EM.  pi.  36.  f  41. 
Barbadoes.      This  species   differs  from 


the  preceding  one   in  the   presence   of 
puncta. 

L.  magnifica  (E.). — Disc  -wdth  its  rays 
alternating  inwards  with  pairs  of  very 
short  striae,  and  connected  exteriorly  by 
a  circlet  of  puncta.  EM.  pi.  36.  f.  42. 
Barbadoes.    (v.  56.) 


Genus  DICTYOLAMPE-A  (Ehr.). — Frustules  orbicular,  not  concatenate ; 
disc  without  an  umbilicus,  but  having  a  circular  cellular  centre,  with  radiat- 
ing striae,  which  alternate  with  other  striae  from  the  margin. 

Dictyolampra  differs  from  the  other  genera  of  this  family  by  its  disc  being 
cellulose  only  in  the  centre,  and  indeed  it  probably  ought,  together  with  Lio- 
stephania and  Actinogonium,  to  form  a  distinct  family ;  but,  having  seen 
no  specimens,  we  are  unable  to  decide  on  their  proper  position. 


Dictyolampra  ^ella  (EM.  pi.  36.  f 

38).  Barbadoes.  The  only  species.  In 
the  centre  is  a  large,  circular,  loosely  cel- 
lulose imibilicus,  with  numerous  (about 


20)  short  radiating  lines,  which  alternate 
with  similar  ones  directed  inwards  from 
the  margin ;  between  the  latter  are  inter- 
posed very  short  marginal  striae,  (v.  58.) 


Genus  MASTOGONIA  (Ehr.).— Frustules  simple  (unequally),  bivalved; 
valves  not  cellulose,  in  lateral  view  circular,  unarmed,  with  lines  radiating 
from  a  stellate  or  angular  umbilicus.  These  forms,  which  were  formerly 
placed  in  Pyxidicula,  may  be  recognized  by  their  unequal  and  angular  valves, 
radiating  veins,  and  noncellular  surface.    The  definitions  of  the  species  in  this 

geniLS  are  unsatisfactoiy,  depending  almost  entu-ely  on  the  number  of  rays 

a  character  which  we  regard  as  very  variable. 

Mastogonia    Crux    (E.).  —  Valves    pl.33.  18.  £8.    Bermuda.    Diam.  1-396". 
large,  one  with  fom-,  the  other  with  seven    Umbilicus  stellate, 
radiating  lines :  apex  not  truncated.  EM.         M.  quinana  (E.). — Valves  laro-e    one 


814 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


■with  five  radiating  lines,  the  other  un- 
known ;  apex  not  truncate.  KSA.  p.  25. 
Bemiuda.  Diam.  1-480".  Scarcely 
more  than  a  variety  of  the  preceding 
species. 

M.  Rota  (E.). — Valves  large,  one  with 
six,  the  other  with  seven  radiating  lines ; 
apices  entire.  KSA.  p.  25.  Bermuda. 
Diam.  1-360".  Probably  another  variety 
of  3/.  Cnix. 

M.  sexcmgida  (E.). — Valves  thin,  one 
with  six  radiating  lines,  the  other  un- 
known; apex  broadly  tnmcate,  with  a 
hexagonal  ai'ea.  EM,  pi.  33.  17.  f.  12. 
Virginia.  Diam.  1-1632".  Resembles  a 
truncated  six-sided  cone.  All  the  above 
species  are  very  smooth  and  crystal- 
line. 

M.  heptagona  (E.). — One  valve  with 


seven,  the  other  with  nine  rays;  apex 
truncated.  Bai  AJS.  xlviii.  pi.  4.  f.  12. 
Bermuda.     Diam.  1-840". 

M.  Ocxdus-Chamceleontis  (E.). — One 
valve  having  eight  radiating  lines  and 
tnmcate  apex,  the  other  unlmown.  KSA. 
p.  25.  =  Pyxidicula  Oculus-  Chamceleontis. 
Maryland.     Diam.  1-1152". 

M.  Actinoptychtis  (E.). — One  valve  with 
9,  the  other  with  13  flexuose  radiating 
lines ;  apices  broadly  tnmcate.  =  Pyxi- 
dicula  ?  Actinoptijchus,  EM.  pi.  18.  f.  19. 
Virginia.  This  species  seems  distinct  in 
its  flexuose  rays  and  the  undulated  mar- 
gin of  its  umbilicus,    (v.  59.) 

M.  Discoplea  (E.).  — Valves  small, 
conic,  with  18  to  20  rays ;  apices  smooth, 
truncate.  KSA.  p.  25.  In  Patagonian 
pumice.     Diam.  1-1152". 


Genus  STEPHANOGONIA  (Ehr.).— Valves  as  in  Mastogonia,  but  their 
truncated  apices  have  spinous  angles. 

Distinguished  by  the  rays  being  prolonged  into  spines,  and  forming  a  fringe 
round  the  umbilicus. 


Stephanogonia  quadrangula  (E.). — 
Valves  thin,  smooth,  with  truncated 
apices,  one  having  four,  the  other  six 
ray-like  angles  and  spines.  KSA.  p.  26. 
Bermuda, 

S.  polygona  (E.). — Valve  with  centi'al 
portion  smooth  and  much  elevated,  united 


to  the  margin  by  an  indefinite  number  of 
rays,  the  spaces  between  which  are  some- 
times faintly  pimctate  ;  the  umbilicus 
sometimes  sm-rounded  with  spines.  Vir- 
ginia and  Bermuda  deposits.  EM.  pi,  33. 
18,  f.  10;  Br  JMS.  viii.  p,  97,  pi.  5. 
f.  8.   (v.  57.) 


Genus  CLADOGRAMMA  (Ehr.).- 
known  to  us. 

Cladogramma  Californicum  (E.).  — 
Valve  orbicular,  not  cellulose,  marked 
^vith  flexuose  lines  radiating  from  the 


-The  characters  of  this  genus  are  un- 


centre,  and  irregularly  forked  or  divided 
near  the  margin.  California.  EM.  pi. 
33.  13,  f.  1**.    {y^u.  11,) 


Genus  HYALODISCUS  (Ehr.). — Erustules  simple,  disciform  ;  disc  smooth, 
flat,  its  umbilical  portion  or  centre  separated  by  a  distinct  sutiu'e. 

Kiitzing  unites  this  genus  with  Cyclotella;  but  its  comparatively  large 
hyahne  disc,  with  a  centre  distinguished  by  an  evident  suture,  and  usually 
somewhat  coloured,  is  perhaps  sufiicient  to  justify  its  removal.  Its  flat  disc 
will  distinguish  it  from  Podosira. 

YiYA.'LOJ)iBCV^Patagonicus(E.'). — Disc 


large,  very  smooth,  its  margin  separated 
from  the  large  centre  by  a  slightly 
grooved  but  not  denticulate  suture ; 
imiction-line  in  front  view  very  tumid. 
EM.  pi.  38,  22.  f.  10,  11.  In  pumice 
from  Patagonia.     Diam.  1-432". 

II.  IcBvis  (E.). — Disc  large,  smooth,  its 
central  portion  separated  by  a  fi'acture- 
like  suture.  EM.  pi.  33.  15.  f.  17.  Cyclo- 
tella /^r?'s,Kiitz.  Virginia,  Diam.  1-456". 
Allied  to  Cyclotella  physoplea.  The  su- 
ture between  the  valves  is  not  tumid. 


and  the  central  portion  of  the  disc  is 
smaller,  and  hence  more  distant  from 
the  rim,  than  in  H.  Patagonicus. 

H.  steUiger  (Bai.). — Disc  with  a  broad 
margin  covered  with  distinct  rectilinear 
rows  of  dots,  arranged  in  groups  so  as 
to  produce  a  stellate  appearance.  BC. 
vii.  Abundant.  St.  Augustine,  Florida. 
"  The  markings  in  this  species  are  quite 
distinct;  and  the  stellate  appearance, 
resembling  that  shown  by  Coscmodiscus 
stibtilis,  will  at  once  distinguish  it  from 
all  other  species,"  B. 


OF  THE  MELOSIRE^. 


815 


H.  suhtilis  (Bai.). — "  Disc  marked  like 
the  engine -turned  back  of  a  watcli,  with 
lines  of  exceeding  delicacy,  only  visible 
by  the  highest  magnifiers  and  careful 
illumination ;  umbilical  portion  more 
coarsely  granulated  and  in  size  little  less 


than  one-third  of  the  diameter  of  the  disc," 
B.  /.  c.  pi.  1.  f.  12.  Halifax,  Nova  Scotia. 
'^  H.  Icevis  differs  by  having  a  wider  mar- 
gin and  much  coarser  markings.  This 
species  forms  an  admirable  test-object," 
B.    (v.  60.) 


Genus  LYSICYCLIA  (Ehr.). — The  characters  of  this  genus  are  unknown 
to  us.  From  Ehrenberg's  figures  it  appears  closely  related  to  Hyalodiscus, 
the  disc  having  a  central,  circular  umbilicus,  and  a  broad  border  separable  at 
the  suture,  as  in  that  genus. 

LYSICYCLIA  Vogelii,  ERBA.  1856,  p.  333,  f.  29.     Central  Africa,    (viii.  39.) 

Genus  PODODISCUS  (Kiitz.).— Frustules  as  in  Podosira,  but  affixed  by  a 
lateral  stipes.  Marine.  We  think  that  the  lateral  position  of  its  stipes  is 
scarcely  sufficient  to  separate  Pododiscus  from  Podosira. 

pi.  16.  f.  28.  On  Enteromorpha  ramidosa, 
Jamaica.     Diam.  1-840".   (xni.  28.) 


Pododiscus  Jamaicensis  (Kiitz.).  — 
Frustules  simple,  concatenate,  smooth  ; 
stipes  elongated,  delicate.     KSA.  p.  26, 


Genus  PODOSIRA  (Ehr.). — Frustules  united  into  short  filaments,  having* 
a  distinct  central  stipes  ;  interstitial  portion  obsolete ;  valve  convex.  Marine. 

In  Podosira  the  lateral  valves  are  vaulted,  and  the  central  portion  is  at 
first  a  mere  connecting  ridge  between  them.  This  ridge,  however,  becomes 
gradually  broader,  and  then  double;  afterwards  an  intermediate  growth 
separates  the  halves  of  the  frustule,  which  meanwhile  do  not  increase  in  size ; 
and  at  last,  when  the  intermediate  space  equals  the  diameter  of  the  original 
frustule,  two  new  frustules  are  formed  by  the  addition  of  a  hemisphere  on 
the  inside  of  each  of  the  separated  portions.  The  outer  silicious  covering* 
stiU  remaining,  the  frustules  are  connected  in  pairs,  and  appear  hke  two 
globules  within  a  joint.  The  valves  usually  have  a  central,  coloured  umbi- 
licus— an  appearance  which  Professor  Smith  attributes,  in  our  opinion  errone- 
ously, to  an  absence  of  silex  at  that  point. 


Podosira  Montagnei  (Kiitz.). — Frus- 
tules subspherical,  dotted ;  connecting 
sheath  with  parallel  annidar  series  of 
minute  stride.  SBD.  ii.  pi.  49.  f.  326. 
=P.  Adriatica,  Me.  on  Diat.  ;  3Ielosira 
qlohifera,  Ra  ANH.  xii.  Britain,  France, 
&c. '  (v.  61.) 

V.Hormoides  (Kiitz.). — Frustules  oval, 
united  into  short  moniliform  filaments  ; 
connecting  sheath  obscm-ely  punctate  ; 
lateral  view  with  umbilicus  but  no  rays. 
SBD.  pi.  49.  f.  327.  =  P.  mimmidoidesi'E,. 
(ii.  45.)  Atlantic,  Britam,  &c.  Di- 
stinguished from  the  preceding  species 
by  its  more  depressed  valves. 


P.  macidcda  (S.). — Disc  with  a  large 
central  umbilicus,  which  is  bordered  by 
an  irregular,  fracture-like  suture,  from 
which  radiate  outwards  several  shadow- 
like bands ;  surface  punctated.  SBD.  ii. 
p.  54,  pi.  49.  f.  328.  Common  in  deep 
water,  guano,  &c.  Britain.  It  may  be 
identical  with  Crasjyedodiscus  Stella,  E. 
P.  conqjressa,  West.  (viii.  34.) 
P.  Icevis  (Greg.).  —  Frustides  trans- 
parent, glassy,  with  very  delicate  oblique 
striae  and  scattered  puncta;  connecting 
zone  distinctly  striated ;  disc  without  a 
distinct  umbilicus.  Grev  MJ.  vii.  p.  85, 
pi.  6.  f.  15-17.     Scotland. 


Genus  MELOSIRA  (Ag.). — Frustules  cylindrical,  discoid,  or  globose,  con- 
nected into  cyhndrical  conferva-like  filaments,  one  or  two  lines  passing 
round  each  frustule  near  the  centre.  =  Gallionella,  Ehi*.  Maritime  and  aquatic. 
This  genus  is  easily  distinguished  from  the  other  genera  of  the  Diatomaceae 
except  Pododiscus,  with  which  the  species  in  its  first  section  closely  correspond 
in  character.  The  filaments  are  remarkable  for  their  conferva-like  appear- 
ance, but  may  be  known  by  their  brown  colour  and  very  fragile  nature.   The 


816 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


species  are  numerous,  and  sometimes  differ  veiy  slightly  ;  we  fear  indeed  that 
several  of  them  have  been  constituted  upon  insufficient  grounds.  Attempts, 
more  or  less  successful,  have  been  made  to  remove  some  species,  and  to  form 
wdth  them  new  genera.  We  have  used  these  divisions  as  sections,  partly 
because  we  are  unable  to  find  at  present  differential  characters  sufficient  to 
justify  a  more  complete  separation,  and  partly  because  we  cannot  decide 
absolutely  on  the  proper  position  of  several  species.  The  following  are  the 
sections  we  have  adopted  : — 

*  Lijs'ujonium. — Joints  globose  or  elliptic,  with  a  ring-like  keel  round  each 
valve.  In  this  section  the  fnistules  resemble  in  form  those  of  the  two  pre- 
ceding genera,  but  are  distinguished  by  their  carinated  valves.  The  suture 
is  a  ridge  between  the  valves. 

2  *  GallioneUa. — Joints  cylindrical  or  suborbicular,  with  a  single  median 
furrow,  and  more  or  less  rounded  ends,  generally  binately  connected ;  valves 
not  carinated.  The  filaments  are  more  or  less  internipted  at  their  margins, 
and  the  junction-siu'faces  are  not  denticulated. 

3  *  Aidacosira. — Joints  cylindiical,  bisulcate,  with  more  or  less  rounded 
extremities.  The  genus  Aulacosira  was  proposed  by  Mr.  Thwaites  for 
"  those  species  characterized  by  the  absence  in  the  frustule  of  an  evident 
central  line  indicating  the  place  of  subsequent  fissiparous  division,  but  each 
frustule  having  two  somewhat  distant  sulci  or  fossulte  passing  round  it."  We 
have  found  the  sulci  constant;  but  Professor  Smith  believes  "the  characters 
have  no  real  existence,  and  owe  their  apparent  presence  in  the  species  Mr. 
Thwaites  adopted  as  his  type,  \iz.  Mehsira  crenulata,  Kiitz.,  only  to  accident, 
or  observation  under  imperfect  illumination.  A  careful  study  of  the  specimens 
from  Aberdeen,  upon  which  Mr.  Thwaites  himself  founded  his  remarks,  and 
of  gatherings  from  various  other  localities,  has  failed  to  satisfy  "  him  "  that  any 
essential  differences  exist  between  this  species  and  other  Orthosirse." 

4  *  Orthosira. — Joints  exactly  cylindrical,  marked  by  a  central  line,  con- 
nected into  an  uninterrupted  cylindrical  filament;  internal  cavity  often 
spherical  or  subspherical  (Thwaites).  Orthosira  contains  "  those  species 
the  frustules  of  which  are  not  at  all  convex  at  the  extremities,  and  which 
therefore  form,  by  their  close  contact,  an  uninterrupted  cylindiical  filament " 
(Thwaites).  Professor  Smith  distributes  the  species  of  Melosira  under  two 
genera,  Melosira  and  Orthosira,  which  he  thus  defines.  Melosira  :  "  Fila- 
ments cylindrical,  of  numerous  frustules,  attached  or  free  ;  frustules  spherical 
or  subcylindiical,  more  or  less  convex  at  the  junction-surfaces."  Orthosira : 
^'  Filaments  cylindrical,  of  numerous  frustules,  continuous,  attached  or  free ; 
frustules  and  valves  cylindiical ;  junction- surfaces  plain,  hue  of  junction 
usually  spinous  or  denticulated."  We  regret  that  in  the  present  state  of  our 
knowledge  we  cannot  adopt  Orthosira  as  a  substantive  genus.  Its  junction- 
margins,  indeed,  are  usually  denticulate  or  spinous,  a  character  we  do  not  find 
in  Melosira  as  defined  by  Professor  Smith  ;  but  this  character  is  not  considered 
essential.  In  our  opinion,  too,  there  is  greater  affinity  between  "  Melosira 
distans''  and  ''  Orthosira  orichcdcea  "  than  between  the  latter  and  ''  Orthosira 
sulcata^  Melosira  is  of  peculiar  interest,  as  it  affords  the  most  frequent 
examples  of  that  form  of  reproduction  in  which  the  valves  of  a  fi'ustule  sepa- 
rate, and  a  sporangium  is  formed  between  them,  unattended  by  conjugation. 


*  Frustules  encircled  tvith  median  and 
lateral  ridges.     Lysigonium. 

Melosira  nummuloides  (Dillw^n, 
Ag.). — Frustules  spherical,  very  finely 
punctured ;  valves  carinated.     ^^^ 


Sbd. 


p.  56,  pi.  49.  f.  329.  =M.  discigera,  Ag. 
Marine  and  brackish  waters.  Eui'ope, 
America,  (v.  64.  xi.  14.)  Diam.  1-1700" 
to  1-860".  Frustules  globular,  united 
in  pairs,  forming  a  moniliform  filament ; 
each  divided  into  hemispheres  by  a  cen- 


OF  TUE  MELOSIRE-E. 


817 


tral  ridge  and  crossed  by  fainter  lines  at 
each  end.  Professor  Kiitzing  describes 
it  as  of  a  golden  coloiu*  wlien  dry ;  oiu* 
specimens  are  gi-eenish.  Sporangial  frus- 
tules  larger,  concatenated,  originating 
from  tlie  temiinal  frustule  only.  Ac- 
cording to  Kiitzing,  the  friistules  in  this 
species  are  ternately,  and  in  the  next  bi- 
nately  conjoined ;  this  does  not  coincide 
with  our  experience.  The  only  species 
likely  to  be  confounded  \v4th  it  is  the 
following. 

M.  salina  (K.). — Smaller;  valves  of 
the  binate  frustules  achromatic,  smooth  -, 
keels  very  fine.  KB.  p.  52,  pi.  3.  f.  4.  = 
GalUonella  nwiunuloides,  El.  p.  167. 
/3.  concatenata,  more  distinctly  stipitate ; 
frustules  concatenated  by  a  distinct  isth- 
mus, KB.  pi.  3.  f.  5.  Brackish  waters. 
Europe.  This  species  difters  from  31. 
nmnmuloides  by  its  less  conspicuous 
keels  and  more  distinct  stipes.  Pro- 
fessor Smith  imites  them ;  for  "  forms 
aberrant  in  these  respects  are  so  fre- 
quently intermixed  with  the  ordinarj^ 
frustules  that  "  he  ^'  cannot  regard  such 
pecidiarities  as  of  specific  importance." 

M.  Westii  (S.).  —  Frustules  sub- 
globidar ;  valves  conical,  with  truncated 
apices  and  a  sutural  and  median  sili- 
cious  ring.  SBD.  ii.  p.  59,  pi.  52.  f.  333. 
Stomach  of  Pecten,  coast  of  Sussex. 
This  species  seems  distinct  in  the 
strongly  marked  central  and  lateral 
ridges. 

2  *  Joints  hinately  or  ternately  conjoined ; 
valves  with  rounded  ends,  neither  cari- 
nated  nor  denticulated,     GallioneUa. 

M.  moniliformis  (Mlill.,  Ag,). — Joints 
rather  longer  than  broad,  finely  punc- 
tated, binately  conjoined,  with  rounded 
ends.  KB.  pi.  3,  f.  2.  =31.  Borreri,  Gr.  ; 
GallioneUa  7nonilifor7nis,  E.  Common  in 
brackish  and  marine  waters.  Diam. 
1-860".  Kutzing  describes  this  species 
as  having  ternately  conjoined  frustules 
concatenated  by  a  distinct  isthmus. 
Sporangial  frustules  larger,  concatenated, 
and,  according  to  Professor  Smith,  origi- 
nating only  in  the  terminal  frustides  of 
the  filament,     (v.  71.) 

M.  lineata  (Dillw^Ti,  Ag.).  —  Joints 
cylindrical,  smooth,  binately  conjoined, 
with  rounded  ends ;  pairs  closely  adnate. 
KB.  p.  53,  pi.  3.  f.  1=  GallioneUa  lineata, 
E.  Marine.  Europe.  A  single  filament 
sometimes  consists  of  from  1200  to  4000 
frustules,  forming  a  chain  2  or  3  inches 
in  length.  Length  of  ioint  1-1400"  to 
1-430"?  "  ^ 

^i,  duhia  (Kiitz,).  —  Smaller;    articu- 


lations depressed,  spheroidal,  smootli. 
KB.  p.  53,  pi.  3.  f.  6,  Marine,  neai*  Cux- 
haven.     Diam.  1-1200". 

M.  Jurr/ensii  (Ag.). — Slender;  joints 
smooth,  elongated,  with  two  slight  con- 

[  strictions  beneath  the  silicious  sheath ; 

j  junction-surfaces  convex,  hemispherical, 

j  closely  concatenate.      KB.  p.  54,  pi.  2. 

I  f.  15.  =  i)/.  suhjlexilis,  SBD.  pi.  51,  f.  331. 
Brackisli  waters.  Em*ope.  Diam.  1-800" 
to  1-1200".  There  is  only  one  sutural 
line,  having  usually  on  each  side  of  it  a 
slight  constriction.  As  in  31.  varians, 
the  inflated  joints  are  interstitial,  and 
closely  united  to  the  parent  frustule. 
M.  Jurgensii  differs  from  31.  suhjlexilis 
in  its  marine  habitat  and  more  closely 
connected  joints  ;  but  we  find  it  difficidt 
always  to  discriminate  them.  The  joints 
are  more  miiform  than  in  31.  varians, 
usually  longer  in  proportion  to  theii* 
breadth,  and  with  more-rounded  ends, 
especially  in  the  new-formed  valves. 
(V.63.) 

M.  suhJlexdis(K.). — F'rustules  cylindri- 
cal, smooth,  binately  conjoined,  yoimger 
ones  elongated,  adult  shorter,  depressed 
ends  slio-htlv  convex ;  pairs  united  bv  a 
short  is'thnius.  ICB.  p.  53,  pi.  2.  f.  13. 
Rividets.  Em-ope.  Diam.  1-560".  Re- 
sembles 31.  varians  with  the  binate  frus- 
tules connected  by  short  interstitial  pro- 
cesses. Professor  Smith  thinks  this 
species  identical  with  Conferva  lineata, 
Dill.  Sporangial  frustules  as  in  31.  mo- 
niliformis. 

M.  varians  (Ag.). — Joints  cylindrical, 
irregidarly  binately  conjoined;  ends  flat 
with  rounded  angles,  closely  adnate; 
disc  with  verv  delicate,  radiating  mar- 
ginal stride.  SBD.  pi.  51.  f.  332=  Gallio- 
neUa varians,  Ehr.  Fresh  water ;  every- 
where common,  ^.(pqualis,  all  the  joints 
quadrate ;  31.  cequalis,  Ag.  This  species 
varies  much,  both  in  size  and  length  of 
joints;  the  margins  of  the  filament  are 
more  or  less  interrupted ;  but  the  ge- 
minate arrangement  of  the  frustules  is 
often  very  obscure  ;  the  valves,  although, 
as  in  most  other  Diatoms,  they  are  really 
dotted,  appear  smooth  unless  magnified. 
The  sporangial  cells  are  inflated  and  in- 
terstitial; Professor  Smith  describes 
them  as  at  first  globular,  but  afterwards 
dividing  (as  in  the  preceding  species)  and 
becoming  cylindrical,  whilst  liabenhorst 
gives  a  completely  different  account  of 
them.  The  latter  says  "  that  on  forma- 
tion of  the  inflated  cell,  its  gi-anules,  at 
first  irregularly  formed,  become  oblongo- 
ovate.  Motion  takes  place  as  in  ordinary 
zoospores.  The  cell  opens,  the  granules 
3g 


818 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


stream  forth,  and  two  elongated  cilia 
become  visible  at  their  hyaline  smaller 
end.  Their  movement  lasts  for  a  very 
short  period ;  they  settle  do\^ai,  and 
quickly  equal  or  surpass  in  size  the 
mother-cell."  If  this  description  be  cor- 
rect, it  will  add  an  important  fact  in  sup- 
port of  their  vegetable  nature.  Professor 
Smith  makes  the  following  diagnostic 
remarks  upon  this  species  : — "  The  only 
species  with  M^hich  this  form  can  be  con- 
founded is  31.  suhJlexUis ;  but  M.  variam 
has  the  extremities  of  its  frustules  closely 
applied  and  partially  truncate  ;  those  of 
M.  suhJlexiUs  are  often  more  or  less 
separated  by  a  mucous  cushion,  and  di- 
stinctly convex.  .  .  .  M.  suhflexilis,  when 
in  abundance,  appears  as  a  dark-gTeen 
iridescent  mass.  31.  varians  always  pre- 
sents a  rich  golden-yellow  or  chestnut 
to  the  eye.  The  geminate  arrangement 
of  the  frustules  is  conspicuous  in  31.  snb- 
JlexiUs,  and  indistinct  in  31.  varians.^'' 
SBD.  ii.  p.  58.  The  fossil  frustules  of 
this  species  constitute  the  gTeater  part 
of  the  earthy  deposits  of  white  powder 
used  in  polishins;  silver  plate,  (iv.  32 ; 
IX.*  131 J  XY.320 

3  *  Fnistulcs  ci/lindrical ,  hlsulcate,  ivith 
rounded  junction-margins. 

M.  disfans  (E.,  K.).  —  Slender;  joints 
cylindrical,  smooth  or  indistinctly  pmic- 
tated,  ^dth  two  distant,  delicate,  ring- 
like fuiTows,  all  closely  connected ;  disc 
plane.  KB.  p.  54,  pi  2.  f.  12.  Fresh 
■water.  Europe,  Asia,  Australia,  Africa, 
and  America.  Fossil,  Bilin,  &c.  Diam. 
1-3456"  to  1-8C4".  Joints  once  to  t^^dce 
as  long  as  broad. 

M.  nivalis  (S.). — .Joints  subcylindrical ; 
valves  subhemispherical,  distinctly  cel- 
lulate ;  extremities  more  or  less  trimcate  ; 
disc  dotted.  SBD.  ii.  p.  68,  pi.  53.  f. 
336.  =  Coscinodiscus  minor,  SBD.  i.  p.  23, 
pi.  3.  f.  36.  Fresh  water  in  iVlpine  di- 
stricts. Britain.  According  to  Professor 
Smith,  this  form  hardly  differs  from 
M.  distatis,  except  in  the  greater  di- 
stinctness of  the  cellules,  and  may  not 
be  distinct. 

M.  orichalcea  (Mortens,  K.). — Slender; 
joints  obscurely  punctated,  mostly  longer 
than  broad,  closely  binately  conjoined, 
with  sliglitly  crenidate  ends  and  tw^o 
median  furrows ;  disc  plane.  KB.  p.  54, 
t.  2.  f.  14.  =  GalUonclla  aurichalcea,  Ehr 
Inf.  Fresh  water.  Common.  Europe, 
Asia,  Africa,  and  America.  Younger 
joints  two  or  three  times  as  long  as 
broad ;  older  ones  shorter.  This  species 
differs  from  31.  Italica   merely  in   its 


more  obscure  crenations  and  apparently 
smooth  disc;  and  perhaps  Professor 
Smith  rightly  united  them.  Its  Hat  and 
closely  comiected  ends  distingiush  it 
from  31.  varians.    (v.  65 ;  mttl.  33.) 

M.  Italica  (E.,  K.). — Slender ;  joints 
cylindrical,  longer  than  broad,  with  den- 
ticulated ends  and  two  median  furrows ; 
disc  with  striated  border.  KB.  p.  55, 
pi.  2.  f  6.  =  GallioneUa  Italica,  Ehr. ;  G. 
crenata,  EM.  many  figiu-es ;  G.  crenn- 
lata,  EA.  pi.  2.  1.  f.  14 ;  3Ielosira  ori- 
chalcea, llalfs,  Annals,  xii ;  Aidacosira 
cremdata,  Thwaites;  Orfhosira  orichalcea, 
SBD.  ii.  p.  61,  pL  53.  f.  337.  Fresh 
water.  Europe,  Asia,  Australia,  Africa, 
and  America,  (xi.29,  xy.33.)  (3.  Binde- 
rana,  Kiitz.,  more  slender;  joints  four 
to  eight  times  as  long  as  broad,  often 
inflated;  disc  striated,  KB.  pi.  2.  f.  1. 
Hamburgh.  Mr.  Thwaites  describes  the 
sporangium  as  orbicular,  wdth  its  axis  of 
elongation  at  right  angles  to  that  of  the 
frustide  from  which  it  originated;  but 
Professor  Smith's  experience  did  not  en- 
able him  fidly  to  conhrm  Mr.  Thwaites's 
observations. 

M.  coarctata  (E.). — Joints  smooth.  Its 
habit  is  that  of  31.  varians,  but  its  disc 
is  not  striated.  E  A.  pi.  3.  5.  f.  9.  Mexico, 
(xi.  20  &  27.)  Kiitzing  miites  this  form 
with  M.  orichalcea. 

M.  Roseana  (Rab.).  —  Joints  longer 
than  broad,  w4th  two  broad  constrictions 
and  dentated  truncate  junction-margins; 
disc  with  radiating  stripe  and  three  or 
more  central  dots.  Rab  D.  p.  13,  t.  10. 
=  Orthosira  spinosa,  SBD.  ii.  p.  61,  pi. 
61.  f.  386.  Europe.  Caves,  in  moss,  on 
trees,  kc. ;  probably  conmion.  Much  as 
they  diftier  in  appearance,  the  late  Pro- 
fessor Gregory  considered  that  he  had 
traced  the  Liparogyra  spiralis  into  this 
species;  and  certainly  the  two  forms 
are  almost  invariably  found  together. 
(V.  67.) 

M.  IcBvis  (E.)  =  GallioneUa  Icevis,  EM. 
pis.  9,  14  tfe  33.  Ehrenberg  gives  up- 
wards of  fifty  habitats  in  Australia,  Asia, 
Africa,  and  America.  His  figures  of  this 
species  differ  considerably  from  each 
other,  and,  in  the  absence  of  description, 
render  it  difficult  to  form  any  idea  of  the 
specific  characters.  Ehrenberg  (/.  c.  p. 
118)  says  it  is  allied  to  Stqyhanodisciis 
Epidendron,  and  we  strongly  suspect 
that  both  these  forms  ought  to  be  miited 
to  31.  Roseana. 

M.  piiJeata  (E.,  K.). — Joints  shorter 
than  broad,  smooth,  with  two  finely 
punctated,  widely  separated  sutures. 
Junction-portions  convex,  smooth,  often 


OF  THE  MELOSIRE^. 


819 


narrower  than  the  intermediate  portion 
(cingulum) ;  hence  the  hat-like  form. 
KSA.  p.  SI.  =  Gallionella  pileata,  ERBA. 
1844  J  M.  pi.  35  a.  21.  f.  11.  Antarctic 
Sea.     Diam.  1-648". 

4  *  Joints  cylindrical,  connected  into  an 
uninterrupted  Jilament ;  internal  cavity 
often  spherical  or  suhspherical. 

M.  arenaria  (Moore).  —  Filaments 
stout,  cim'ed  ;  joints  cylindrical,  mostly 
shorter  than  broad,  closely  united  with 
denticulated  j  unction-margins  and  a  line 
of  puncta  on  each  side  of  suture ;  disc 
with  radiating  striae  and  punctated 
centre.  Ralls,  ANH.  xii.  pi.  9.  f.  4.  = 
Orthosira  arenaria,  SBD.  ii.  p.  59,  pi.  52. 
f.  334 ;  Gallionella  hiseriata,  EM.  pi.  15 
A,  f.  5-7.  Fresh  water.  Europe.  Easily 
recognized  by  its  great  size.     (viii.  17.) 

M.  undulata  (E.,  K.).  — Stout;  joints 
longer  than  broad,  constricted  within  the 
sheath,  hence  undulate ;  disc  slightly 
convex,  very  finely  radiated.  KSA.  p.  29. 
=  Gallionella  undulata,  EM.  pi.  11.  f.  2,  3. 
Europe  and  Africa.  Professor  Smith 
refers  this  form  to  M.  arenaria. 

M.  punctigefra.=  Gallionella  punctigera, 
EM.  pi.  12.  f.  9.  Fossil.  Germany. 
Ehrenberg's  figure  represents  a  large 
species,  perhaps  not  distinct  from  M. 
arenaria.       Joints    wdthin    a    common 


longer  than  broad,  constricted  on  each 
side  of  the  suture,  and  having  a  series  of 
dots  along  the  junction-margins.  Disc 
with  numerous  radiating  dotted  lines 
and  a  smooth  umbilicus. 

M.  Sol  (E.,  K.).  —  Joints  coin-like, 
five  times  shorter  than  broad  ;  disc  plane, 
large,  strongly  and  broadly  radiated,  with 
a  smooth  umbilicus  and  narrow  smooth 
rim.  KSA.  p.  Sl.=  Gallionella  Sol,  EM. 
pi.  35  A.  22.  f.  12.  Antarctic  Sea.  Rays 
84 ;  suture  of  valves  single.  Diam. 
1-336''.  This  species  rivals  31.  arenaria 
in  size,  and  somewhat  resembles  it  in 
appearance,  but  is  marine. 

M.  Oculus  (E.,  K.).— Habit  of  31.  Sol, 
but  larger,  with  equal  and  stouter  rays. 
KSA.  p.  31.  ERBA.  1844,  p.  202.  Ant- 
arctic Sea.  Rays  67.  Diam.  1-240". 
Probably  a  state  of  3f.  Sol. 

M.  Tympanum  (E.,  K.).  —  Disc  very 
broad,  with  a  smooth  centre  and  a  nar- 
row, tinelv  striated  margin.  KSA.  p.  31 ; 
ERBA.  1844,  p.  202.     Antarctic  Sea. 

M.  calligera  (E.,  K.).  —  Joints  small, 
smooth,  having  the  habit  of  31.  distans, 
but  with  a  single  median  suture  and  an 
enclosed,  double,  granular  mass  (as  in 
31.  undulata).     KSA.  p.  31.  =  Gallionella 


calligera,  ERBA.  1845;   EM.  pi.  12.  f.  9 

k,  I.  FossU  in  pumice.  Island  of  Ascen- 
sion.    Diam.  1-1728". 

M.  sculpta  (E.,  K.).  —  Joints  not  so 
long  as  broad,  densely  striated,  and  ele- 
gantl}'  sculptured  with  horizontal  pimc- 
tated  lines ;  sutm'e  a  narrow  smooth 
band ;  disc  with  radiating  pimctated 
lines.  KSA.  31.  =  Gallionella  sculpta, 
EM.  pi.  33.  12.  f.  20,  21.  Fossil.  Ore- 
gon.    Diam.  1-960".     Frustules  oval. 

M.  Campylosira.  =  Gallionella  Cam- 
pylosira,  EM.  pi.  35  a.  13  b.  f.  1-3. 
Elbe.  Resembles  31.  sculpta,  but  smaller. 
Joints  suborbicular,  within  an  iminter- 
rupted  sheath,  with  horizontal  dotted 
lines  on  each  side  of  a  narrow,  smooth 
sutural  interspace  ;  disc  with  marginal 
radiating  lines. 

M.  Californica  (E.).  —  Joints  broader 
than  lono-,  densely  and  strongly  striated 
with  horizontal  punctated  lines;  sutural 
interval  smooth,  not  distinct.  =  Gallio- 
nella Californica,  ERBA.  1852,  p.  534. 
Fresh  water.  California.  Very  much 
akin  to  the  fossil  31.  sculpta,  and  both 
forms  closely  approach  31.  granulata. 
Frequently  the  granulated,  dome-shaped 
terminal  discs  are  foimd  dispersed 
amongst  the  truncated  joints.  Perhaps 
therefore  this  form,  with  31.  Horologium, 
should  be  referred  to  the  peculiar  genus 
Sph?erotermia. 

M.  Horologium  =  Gallionella  vel 
Sphcerotermia  Horologium,  EM.  pi.  33, 
2.  f.  17.  Fossil.  Siberia.  We  have 
seen  no  description  of  this  species,  or  of 
Ehrenberg's  genus,  Sphaerotermia.  Frus- 
tule  ^\dth  horizontal  strise  inteiTupted  by 
the  smooth  sutural  band ;  disc  with  a 
large,  defijiite,  smooth  mnbilicus  and 
distant  radiating  striae,  terminating  at 
inner  ends  in  a  circlet  of  gland-like  dots 
(tubercles  ?).    (v.  62.) 

M.  arctica  (Dickie).  —  Joints  globose 
or  oval,  smooth,  the  median  sutm-al  line 
generally  single,  but  duplex  in  subcu- 
taneous division,  with  a  smooth  band 
interposed.  =  Gallionella  arctica,  ERBA. 
1853,  p.  528  ;  EM.  pi.  35  a.  f.  1, 2.  Mel- 
ville and  Kingston  Bays.  In  Ehrenberg's 
figures  the  frustules  are  within  a  common 
continuous  sheath,  and  marked  with  hori- 
zontal series  of  puncta. 

M.  sulcata  (E.,  K.).  —  Joints  shorter 
than  broad,  with  a  smooth  median  fur- 
row and  pinna-like  cellules  on  each 
side  ;  disc  furnished  ^^^th  radiating  strias, 
which  do  not  reach  the  centre.  KB.  p. 
55,  pi.  2.  f.  7.  =  Gallionella  sulcata,  Ehr.  ; 
Orthosira  marina,  SBD.  ii.  p.  59,  pi.  53. 
f.  338.  Marine.  Frequent,  both  recent 
8g2 


820 


syste;matic  history  of  the  infusoria. 


and  fossil,  (ix.  131  and  xi.  20.)  This 
species,  which  varies  considerably  in 
size,  is  well  marked  by  its  short,  slightly 
angular  joints,  and  its  transverse  scidp- 
ture-like  marks  on  each  side  of  the  su- 
ture. Margin  of  disc  often  denticulate. 
Diam.  1-860"  to  1-600". 

M.  coronata  (E.,  K.). — 31.  sulcata  in 
habit;  joints  cylindrical,  striated;  disc 
smooth,  slightly  convex,  with  a  crenated 
margin  and  a  circlet  of  pearl-like  gra- 
nides  within.  KSA.  p.  31.  =  GaJlionella 
coronata,  EM.  pi.  38.  22.  F.  5.  Marine. 
Asia,  Africa,  Patagonia.  Diam.  1-864". 
It  differs  from  M.  sulcata  only  in  the 
more  distinct  crenations  of  the  disc  and 
the  circlet  of  dots. 

M.  iilana  (E.,  K.).— Habit  of  31.  sul- 
cata ;  but  disc  plane,  smooth,  and  neither 
radiated  nor  granular.  KSA.  p.  31.= 
GallioneUa  lilana,  ERBA.  1845.  Fossil. 
Patagonia.  D.  1-1152".  This  form  may 
possibly  be  31.  sulcata,  with  its  markings 
destroyed  by  igneous  action. 

M.  Hetrurica  (K.).  —  Small ;  joints 
cylindrical,  smooth,  twice  as  long  as 
broad,  vnt\\  finely  denticulated  junction- 
margins  ;  disc  convex,  marked  with 
dotted  ravs.  KB.  p.  55,  pi.  2.  f.  6.  Fossil. 
San  Fiore.     Diam.  1-3600"  to  1-800". 

M.  f/ramdata  (E.). — Joints  longer  than 
broad,  Tvnth  horizontal  punctated  lines 
on  each  side  of  the  median  suture,  and 
denticulated  junction-margins ;  disc  with 
a  series  of  marginal  puncta.  =  GaUioneUa 
granulata,  EA.  p.  123;  ]M.  manv  fisures  ; 
G.  tenerrima,  EM.  pi.  39.  f.  50 ;  Ortlio- 
sira  punctata,  SBD.  ii.  p.  62,  pi.  53.  f. 
339.  Fresh  water.  Ehrenberg  gives 
upwards  of  50  habitats  in  Europe,  Asia, 
and  America. 

M.  /3.  maxima.  Disc  with  31  mar- 
ginal denticulations,  and  sti'ongly  akin 
to  31.  sulcata. 

M.  3Iarchica  (E.). — Resembles  31. 
granulata ;  but  the  dotted  lines  are  pa- 
rallel to  the  suture,  and  not  horizontal.  = 
GaJlionella 3I(n'chica,'EM.  several  figures; 
G.  procera,  EM.  pi.  15  a.  f.  1.  Fresh 
water.  Europe,  Asia,  Africa,  and  Ame- 
rica. 

M.  clccussata  (E.).  —  Resembles  31. 
f/ramdata  ;  but  the  dotted  lines  are  dia- 
gonal and  decussating.  =  GallioneUa  de- 
russata,  EM.  several  figures.  Fresh 
water.  Asia,  Africa,  and  America. 
Kiitzing  includes,  perhaps  correctly,  31. 
3Iarchica  and  31.  (jranulata  under  this 
species. 

M.  lirata  (E.,  K.).— Has  the  habit  of 
31.  granulata,  but  ^^nth  more  conspi- 
cuous lines,  disposed  like  the  strings  of 


a  Ivre.     KSA.  p.  31.=  GallioneUa  lirata, 
EM.  pl.  2.  3.  f.  33.     Fossil.     America. 

M.  spiralis  (E.,K.). — Filaments  cm-ved 
and  spiral;  joints  small,  oblique,  longer 
than  broad,  or  equal,  loosely  punctated 
in  transverse  series.  KSA.  p.  31.  =  Gal- 
lioneUa spiralis,  EM.  pl.  33.  13.  f.  3. 
Fossil.     Oregon.     Diam.  1-2304". 

M.  Americana  (Kiitz.). — Frustules  in- 
cluded in  a  jointed  cylindrical  tube, 
separated  by  dissepiments  of  the  tube, 
elliptic,  with  striated  margins  and  a 
median  furrow;  disc  with  radiating 
styise,  convex.  KB.  pl.  30.  f.  69.  =  Ortho- 
sira  Americana.  Diam.  1-660".  Appa- 
rently fm-nished  with  internal  silicious 
cells. 

M.  Dickieii  (Thwaites,  K.). — Joints 
mostly  longer  than  broad,  smooth  or  ob- 
scurely punctated,  except  by  conspicuous 
dots  bordering  the  sutm-e  ;  disc  obscurely 
punctate  ;  sporangia  ?  fusiform.  KSA. 
p.  889.=  OrtJwsira  Dickieii,  Thwaites, 
ANH.  2nd  series,  i.  pl.  12;  SBD.  ii. 
p.  60,  pl.  52.  f.  335.  Fresh  water.  Cave 
near  Aberdeen,  (xv.  29.)  "  The  fila- 
ments of  this  beautiful  species  consist 
generally  each  of  from  two  to  four  frus- 
tules, which  are  hyaline  and  perfectly 
smooth  ;  central  cavity  filled  wath  dark 
red-brown  endochrome  ;  sporangium 
fusiform,  marked  with  numerous  annular 
constrictions,  whose  formation  is  pro- 
gressive, and  which  go  on  increasing 
until  the  sporangium  is  fully  developed 
(xv.  296.  29  B.  a  filament,  the  tenninal 
cells  of  which  have  each  commenced  to 
develope  a  sporangium ;  and  f.  29  c.  a 
mature  sporangium).  This  formation 
thus  occurs :  at  the  commencement  of 
the  formation  of  a  sporangium,  the  endo- 
chrome, at  the  same  time  that  it  with- 
draws from  the  end  of  the  fi'ustule,  pro- 
duces at  its  centre  an  additional  ring  of 
cell-membrane ;  and,  this  process  con- 
tinuing to  take  place  at  certain  intervals, 
each  new  ring  of  cell-membrane  exceed- 
ing in  diameter  those  previously  formed, 
produces  at  length  the  structure  repre- 
sented in  f.  29  c ;  or  it  may  be  a  more 
correct  explanation  of  the  process  to  say 
that  an  entii'e  new  cell-membrane  has 
been  developed  by  the  young  sporangiimi 
at  the  time  each  new  ring  has  been 
formed,  and  that  thus  have  originated 
the  several  chambers  into  which  the  ends 
of  the  sporangium  are  divided;  fissi- 
parous  division  subsequently  takes  place, 
and  sporangial  frustules  are  developed 
from  each  half,  as  shown  in  f.  29  d." 
Professor  Smith  doubted  whether  the 
fusifonn  bodies  are  sporangia,  as  ^^this 


OF  THE  MELOSIEE^. 


821 


mode  of  development^  in  the  formation 
of  sporangia,  stands  alone  and  imsup- 
ported  —  a  serious  difficulty  in  tlie  way 
of  admitting  Mr.  Thwaites's  conclu- 
sions." For  this  and  other  reasons,  he 
was  disposed  to  refer  the  process  to  the 
development  of  internal  cells,  as  in  Meri- 
dion,  Himantidium,  Odontidium,  and 
Achnanthes,  and  recorded  his  impression 
that  the  process  was  not  connected  Avith 
the  sporangia. 

M.  temds  (K.). — Very  slender;  joints 
cylindrical,  smooth,  longer  than  broad, 
closelv  connected,  produced  at  their 
jimction.  KB.  p.  54,  pi.  2.  f.  2.  In  the 
polishino-  powder  of  Limeberg.  Diani. 
1-5760".'^ 

M.  Garganwa  (Rab.). — Very  slender ; 
joints  two  or  three  times  as  long  as 
broad,  with  stout,  protuberant,  indi- 
stinctly dentate  junctions;  disc  flat, 
punctated  on  the  periphery.  Rab  D.  p. 
14,  t  2.  f.  8.  Italy.  After  burning,  it 
reminds  one  of  M.  tenuis. 

Doiihtfid  and  imperfectly  described 
Species. 

M.  Do:iyana  (Van  den  Bosch). — Joints 
cylindrical,  finely  punctated;  length 
equal  to  or  a  little  longer  than  the 
breadth.  KSA.  p.  29.  Stagnant  water. 
HoUand.     Diani.  1-1152"  to  1-770". 

M.  circularis.  —  GaUionella  circidaris. 
EM.  pi.  35  A.  9.  f.  3.  Asia  and  America. 
Filaments  slender, curved ;  joints  broader 
than  long,  closely  connected,  smooth, 
with  a  single  sutural  line. 

M.  Gallica.  =  GaUionella  Gallica,  EM. 
pi.  9.  2.  f.  2.  Fossil.  France,  The 
frustule  has  one  diameter  twice  as  long 
as  the  other,  and  no  suture  or  string. 

M.  halophila  =  GaUionella  hahphila, 
EM.  pi.  37.  5.  f.  1.  Em-ope.  Frustules 
minute,  smooth. 

M.  tcBniata—  GaUionella  tceniata,  EM. 
pi.  39.  3.  f.  65.  Atmospheric  dust.  The 
figm'e  shows  a  single  subquadrate  frus- 
tule, wdthout  any  distinguishing  cha- 
racter. 

M.  trachealis  =  GaUionella  trachealis, 
EM.  pi.  8.  2.  f.  18.  Hungary.  Ehren- 
berg's  figure  is  too  imperfect  to  be  in- 
telligible. 

M.  laminaris  =  GaUionella  laminaris, 
EM.  pi.  39.  3.  f.  64.  Asia.^  The  imper- 
fect figure  shows  striated  junction-mar- 
gins. 

M.  Scala  =  GaUionella  Scaki,  EM.  pi. 
8.  1.  f.  24.  Hungary.  The  figure  re- 
presents a  slender  continuous  filament, 
di^dded  into  smooth  quadrate  joints. 

M.  ?  mesodon  =  GaUionella  ?   mesodon 


{Fragilaria  mesodon  Y),  EM,  pi.  11.  f.  10. 
Bohemia.  Filament  slender,  conti- 
nuous, with  smooth  subquadrate  joints, 
having  two  puncta  at  each  outer  margin, 
as  in  Fragilaria. 

M.  ocliracea.  =  GaUionella  ferrwjinea 
(Ralfs). — Slender,  oval,  convex  at  both 
ends ;  smooth.  In  many,  perhaps  in  all 
chalybeate  waters,  and  also  in  peat- 
water,  which  contains  a  small  proportion 
of  iron,  this  is  to  be  foimd ;  it  is  of  the 
colour  of  iron-rust,  and  in  mineral 
springs,  in  which  it  abounds,  is  often 
taken  for  precipitated  oxide  of  iron.  It 
covers  everything  under  water,  but 
forms  so  delicate  and  floccose  a  mass, 
that  the  least  motion  dissipates  it.  In 
the  spring  of  the  year,  this  mass  is  com- 
posed of  very  delicate  pale-yellow  glo- 
bules, which  can  be  easily  separated 
from  each  other.  They  unite  together 
in  rows,  like  short  chains,  and  produce 
an  irregular  gelatinous  felt  or  floccose 
substance.  About  summer,  or  in  autumn, 
they  become  developed  into  more  evi- 
dently articulated  and  stilF  threads,  of  a 
somewhat  larger  diameter,  but  still  form 
a  complicated  mass  or  w^eb,  and,  either 
from  adhering  to  each  other  or  to  deli- 
cate Confervfe,  appear  branched ;  in  the 
young  condition,  when  examined  imder 
shallow  magnifiers,  they  resemble  gela- 
tine ;  but  with  a  power  of  300  diameters, 
the  flexible  granules  are  discoverable, 
and,  with  dexterous  management,  the 
little  chains  fomiing  the  felt  or  floccose 
web  can  be  made  out.  In  summer,  on 
the  other  hand,  its  structm-e  can  be  ob- 
served much  more  easily  and  distinctly. 
Early  in  spring,  the  colour  is  that  of  a 
pale  yellow  ochre  ;  but  in  summer,  that 
of  an  intense  rusty  red.    Diam.  1-1200". 

According  to  Kiitzing,  this  is  not  a 
species  of  GaUionella,  but  a  ConfeiTa; 
it  has  no  true  silicious  lorica,  as  have 
true  Diatomese  ;  and  the  coating  of  oxide 
of  iron  is  not  an  essential  element,  but 
merely  an  incrustation,  such  as  will  form 
on  well-knoAvai  Confervas  placed  imder 
like  circumstances,  /.  e.  in  water  holding- 
salts  of  iron  in  solution,  which  are  sub- 
sequently precipitated  by  exposure  to 
the  air,  and  converted  into  the  red  oxide. 

The  same  author  dift'ers  from  Ehren- 
berg  as  to  the  part  played  by  the  so- 
called  GaUionella  ferrurjinea  in  the  pro- 
duction of  the  oxide  of  iron  in  chalybeate 
waters,  of  bog-iron  ore,  of  clay-iron  ochre, 
&c.  For,  he  observes,  in  many  springs 
rich  in  iron  no  such  organism  is  foimd, 
although  other  Confervce  may  be  present 
—  Conferva^,  however,  not  pecidiar  to 


822 


SYSTEMATIC  HISTOEY  OF  THE  rN'FrSORlA. 


siicli  habitats,  but  common  in  springs 
and  ponds  generally. 

Mr.  Ralls  (op.  cit.  p.  852),  however, 
in  part  supports  Ehrenberg,  declaring 
that,  though  identical  with  Conferva 
ochracea  (Uillwyn),  yet  "Ehrenberg  is 
no  doubt  correct  in  placing  the  plant  in 
this  genus,  as  the  filaments  are  silicious 
and  cylindi'ical." 

Nageli  describes  and  figures  a  species 
which  he  refers  to  the  genus  Gallionella ; 
but  it  is  a  doubtful  membigr.  His  de- 
scription, however,  especially  that  of  the 
self-division,  induces  us  to  give  it  nearly 
in  his  own  words,  with  his  name  (Ray 
Society,  1846,  p.  219). 

M.  Ndqell  (R.).  —  Shortlv  cvlindi'ical ; 
diam.  •014'"  to  -027'".    Marine!'    Naples. 

"Both  the  terminal  surfaces  of  the 
cylinder  are  flattened ;  so  that,  when  seen 
sideways,  it  appears  rectangular,  with 
the  angles  rounded  off.  It  is  composed 
of  one  simple  cell,  whose  membrane  is 
covered  by  a  siliceous  plate;  and  its 
cavity  contains  chlorophyll-gTanules, 
which  lie  upon  the  membrane  in  two 
circular  bands,  (xv.  26-28.)  Each  of 
these  bands  occupies  one  of  the  obtuse 
angles  of  the  cylinder,  and  appears  annu- 
lar from  above,  rectilinear  from  the  side. 

"  In  developing,  the  relative  length  of 
the  cylinder  increasing,  a  septum  divides 
it  into  halves  (xv.  28  c),  which  when 
complete,  the  latter  separate  as  two  di- 
stinct beings.  The  nascent  chlorophyll- 
granules  are  either  spread  equally  over 
the  surface,  or  more  frequently  arranged 
in  radii  from  the  nucleus  in  the  centre  ; 
they  lie  in  the  com'se  of  the  currents 
streaming  fi'om  the  nucleus.  Compared 
with  a  cell  of  Confer^'a,  or  of  Spirogyra, 
all  three  agree  in  the  forming  of  a  septum. 


in  the  similarity  of  their  contents,  and  in 
the  depositions  of  extra-cellidar  sub- 
stance. But  Gallionella  ditfers  fr-om 
both,  by  the  production  of  an  individual 
from  every  cell,  also  by  the  chlorophyll 
forming  two  lateral  bands,  and  the  sili- 
ceous extra-cellular  substance  an  inter- 
mediate one. 

"  So  far  as  my  investigations  go, 
Gallionella,  which,  according  to  Ehren- 
berg,  possesses  a  bivalved  or  multivalved 
shield,  agrees  with  the  above-described 
plant  in  all  essential  particulars.  The 
lines,  for  instance,  which  would  intimate 
a  division  of  the  shell  into  two  or  more 
pieces,  are  the  septa  by  which  the  cell- 
division  is  eflfected.  As  in  the  filiform 
Algae,  these  walls  at  first  appear  as  deli- 
cate lines  ;  then,  by  an  increase  of  thick- 
ness, seem  two  clearly  defined  lines ;  and 
at  last  present  themselves  as  two  lamellae, 
separated  by  an  intermediate  third  line. 
The  perforations  which  Ehrenberg  de- 
scribed, I  look  upon  as  nothing  more 
than  intercellular  spaces,  formed  be- 
tween the  two  new-formed  cells  and  the 
parent  cell.  These  so-called  perforations 
are  only  visible,  therefore,  on  the  two 
lateral  borders  where  the  wall  abuts 
upon  the  membrane.  The  Confervoid 
AJgae  exhibit  a  similar  appearance." 

GallioiieUa  (?)  Novce  HoUandice  (Ehr.), 
Avon  River,  Australia  ;  G.  gibha  (Ehr.), 
fossil,  Georgia;  G.  punctata  (Ehr.), 
Western  Asia;  G,  tincta  (Ehr.),  Ural 
Mountains ;  G.  gemmata  (Ehr.),  Siberia; 
G.  lineolata  (Ehr.),  fossil.  North  Asia; 
G.  undata  (Ehr.),  Himalaya  Mountains ; 
G.  curvata  (Ehr.),  India;  G.  vaginata 
(Ehr.),  India;  G.  Nilotica  (Ehr.),  River 
Nile,  are  species  known  to  us  only  by 
name. 


Genus  ARTHROGYRA  (Ehr.). — The  characters  of  this  genus  are  unknown 
to  us ;  but,  judging  from  Ehrenberg's  figures  of  the  species,  it  seems  to  have 
been  constituted  for  the  reception  of  those  forms  of  Melosfra  which,  like  31. 
Dichieii,  produce  horizontal,  elongated,  tapering  internal  bodies  or  sporangia. 


Abthrogyba  Guatimalensis,  EM.  pi. 
33.  6.  f.  1.  Fem-earth.  Guatemala. — 
Filament  straight,  jointed,  with  crenated 


margin, 
body. 


and  straiofht,  fusifonn  internal 


A.  semilunaris,  EM.  pi.  33.  6.  f.  2. 

Guatemala. — Filament  jointed,  curved, 
\^^th  creriate  margins,  and  semilimate 
internal  body. 


Genus  DISCOSIRA  (Rab.). — Frustules  united  into  a  short  filament,  with 
a  thick  mucous  covering  ;  in  lateral  view  circular,  having  a  uniformly  punc- 
tate centre,  a  border  of  numerous  (24  to  33)  slightly  curved,  oblique,  ray- 
like  lines,  and  a  marginal  crown  of  teeth  (50  to  64). 

DiscosniA  sidcata  (Rab.). — Frustules  I  rows,  which  con-espond  to  the  teeth  of 
in  front  view  with  deep  transverse  fur-  |  the  lateral  surface.    Rab  D.  p.  12,  t.  3.    In 


OF  THE  MELOSrRE.E. 


823 


a  lagoon  at  Manfredonia,  east  coast  of  [  late,  but  requires  the  highest  magnify- 
Italy.     Each  tooth  is  minutely  denticu-  |  iug  powers  to  ascertain  it.     (v.  Q8.) 

Genus  LIPAROGYRA  (Ehr.).— Fnistiiles  simple,  cylindrical,  each  having 
an  internal  spiral  filiform  band  or  crest. 

The  habit  of  this  genus  closely  resembles  that  of  Spirogyra,  a  non-silicious 
genus  of  Algae. 


LiPAROGYBA  dendroteres  (E.).  — 
Frustules  smooth,  ciystalline,  three  or 
fom-  times  as  long  as  broad,  with  an 
internal  spiral  band  j  margin  of  disc 
denticulated.  Rab  D.  p.  12.  =L.  spircdis, 
EM.  pi.  .34.  5  a.  f.  1,  3.  On  ti'unks  of 
trees.  Venezuela.  Thirteen  spii'als  in 
1-360".     (v.  72.) 

L.  circidaris  (E.). — Frustule  witli  13 
annidar  tiutis  of  internal  line  in  1-360". 


Rab.  /.  c.  p.  12.  With  the  preceding,  and 
in  Brazil.  Ehrenberg  says  he  is  not 
satisfied  whether  the  preceding  are  di- 
stinct species,  or  merely  varieties.  Each 
has  a  smooth  disc,  with  three  central 
apiculi. 

L.  scalaris,  EM.  pi.  34.  5  a.  f.  2.  South 
America.  Ehrenberg's  figure  represents 
the  frustide  in  fi"ont  view  as  divided  by 
cross  bars  in  a  ladder-like  manner. 


Genus  POROCYCLIA(Ehr.). — Resembles  Liparog}Ta,  but  is  without  spii-es, 
has  interior  circular  rings,  and  the  margin  of  its  disc-like  ends  a  circlet  of 
deep  impressions.  We  doubt  whether  this  genus  is  sufliciently  distinct  from 
Liparogyra. 


PonocYCLiA  dejidrophila  (E.).  — 
Frustides  smooth,  with  9  annular  lines ; 
disc    with    12     marginal    depressions. 


radiating  series  of  puncta,  and  5  central 
apicidi.  RabD.  p.  12.  On  tiimks  of 
trees.  Venezuela.   L.  1-320" ;  w.  1-560". 


Genus  STEPHANOSIRA  (E.).— Fiiistules  united  into  a  short  filament ; 
disk  with  radiating  series  of  minute  puncta,  and  a  marginal  crowoi  of  teeth. 
In  form  this  genus  resembles  Stephanodiscus,  but  differs  from  it,  and  becomes 
allied  to  Melosira  by  its  imperfect  spontaneous  division,  and  consequent  con- 
catenation, In  Melosira,  however,  the  circlet  of  spines  is  wanting.  We  are 
unacquainted  with  this  genus ;  and  its  characters  scarcely  suffice  to  distinguish 
it  from  Orthosira.     AU  the  known  species  are  found  on  trees. 


Stephanosiba  Epidendron  (E.).  —  i 
Front  view  with  punctated  transverse  j 
lines  and  fmTow.  Rab  D.  p.  14.  On  trees.  , 
Venezuela  and  Brazil.  Larger  diameter  ! 
1-432";  smaUer  1-4320". 

S.  Hamcuh'ijas  (E.).  — In  front  ^-iew 
smooth,  but  with  junction-margins  stri- 
ated ;  disc  having  marginal  radiating 
puncta,  and  its  centre  a  few  scattered 
dots.   Rab.  /.  c.  p.  14.     On  trees  with  the 


preceding  species.     Diameter  1-720". 

S.  Ewiypcea  (E.).  — Frustides  often 
broader  than  long,  smooth,  but  with  very 
faintly  striated  junction-margins.  Rab. 
I.  c.  p.  14.  Among  mosses  on  trees  at 
Berlin.  Much  smaUer  than  the  preced- 
ing. Chain  fonned  of  three  to  four  frus- 
tides, each  1-2304" to  1-1152"  in  depth; 
rarely  1-1200"  in  width. 


Genus  STEPHANODISCUS  (E.).— Disc  with  radiating  series  of  puncri- 
form  granules,  and  furnished  with  a  crovsTi  of  erect  marginal  teeth.  Aquatic. 
Stephanodisci  approximate  in  character  to  Cyclotella,  but  differ  from  them 
by  the  circlet  of  teeth.  They  also  approach  closely  to  the  non-cellulose 
Coseinodisceae,  and  seem  to  have  as  good  a  claim  to  rank  wdth  that  family  as 
mth  the  Melosireae.  Stephanodiscus  drffers  from  Odontodiscus  in  the  same 
manner  as  Peristephania  does  from  Systephania,  and  in  our  opinion  might, 
without  inconvenience,  be  united  to  it. 

Stephaxodiscus  BeroUnensis  (E.).  ;  teeth  (often  32)  on  each  side.  KSA. 
— Small,  discoid;  disc  plane,  finely  radi-  i  p.  21.  Alive,  Berlin.  Diam.  1-1152'.  In- 
ated,  and  furnished  with  acute  marginal  [  ternal  granular  substance  broA^Ti,  lobed. 


824 


SYSTEMATIC  HISTOET  OP  THE  INFUSOEIA. 


S.  jEfiyptkicus,  EM.  pi.  33.  1.  f.  IG. 
E.irypt.  '  Ehreuberg's  figure  represents 
the  disc  witli  series  of  pimcta  radiating 
from  the  centre,  without  a  distinct  um- 
bilicus, the  teeth  numerous,  subulate, 
and  erect,     (v.  69.) 

S.  Sinensh,  EM.  pi.  34.  7.  f.  7.  Canton. 
Ehrenberg's  figure  shows  the  puncta 
arranged  as  in  S.  JEyijiJtiacus,  but  the  rim 
striated,  and  the  teeth  nodule -like  and 
intra-marginal. 

S.  Branmputrce,  EM.  pi.  35  a.  f.  9, 10. 


Ganges.  Puncta  as  in  the  foregoing 
species,  the  rim  furnished  with  short 
triangidar  teeth. 

S._  Niaf/arce  (E.). — Frustules  small; 
disc  with  numerous  (often  G4)  series  of 
punctiform  granules  radiating  from  a 
large  granulated  umbilicus,  and  as  many 
acute  marginal  teeth  as  rays.  EM. 
pi.  35  a.  7.  f.  21,  22.  Niagara.  This 
speci(!S  is  distinguished  by  its  granulated 
umbilicus. 


Genus  PERISTEPHANIA  (Ehr.).— Friistiilcs  simple,  discoid ;  disc  with 
decussating  parallel  series  of  granules,  and  numerous  marginal  teeth.  Mari- 
time. "  The  characters  of  this  genus  so  well  agree  ^^dth  Stejihanodiscus  that 
[>erhaps  we  might  more  correctly  refer  the  deep-sea  form  to  that  genus.  But 
as  the  hitherto  known  Stephanodisci  are  all  fluviatile,  and  the  maritime  form 
in  the  order  of  its  cellules  very  nearly  approaches  the  purely  maritime  Cosci- 
nodiscus  lineaius,  I  have  preferred  not  mixing  fluviatile  8tephanodisci  T\ith 
a  doubtful  maritime  form.  Perhaps  the  flow  in  deep  water  may  have  com- 
mingled a  fluviatile  form  with  the  maritime  ones.  Should,  therefore,  a  similar 
form  be  hereafter  found  in  any  river,  this  generic  name  must  be  cancelled,  and 
the  form  placed  in  Stephanodiscus  "  (EliBA.  1854,  p.  230).  As  we  consider 
iiabitat  altogether  inadmissible  as  a  generic  distinction,  we  Avoiild  distinguish 
Stcphanodiscus  and  Peristephania  by  the  radiating  granules  of  the  former, 
and  their  parallel  arrangement  in  the  latter  genus.  We  should  prefer  to 
unite  this  genus  with  8ystephania,  which  diflers  only  in  having  intra- mar- 
gmal  teeth.  Perhaps  even  Coscinodisms  Vineatus  might  be  included,  thus 
making  the  parallel  arrangement  of  the  granules  the  essential  character. 


Peristephania  Entycha  (E.).  — 
Habit  of  Cosciuodiscus  Uneatus  ]  margin 
of  the  disc  armed  with  numerous  erect, 
crowded  teeth.  EM.  pi.  35  b.  4.  f.^14. 
Deep  soundings  of  the  Atlantic,  (v.  73.) 

P.     lincata     (E.).  —  Puisembles      P. 


Entyclia^  but  its  teeth  are  fewer  and  more 
distant.  EM.  pi.  33. 13.  f.  22.  CaUfomiau 
deposit  and  guano. 

In  both  species  the  teeth  are  minute 
and  triangular. 


Genus  PYXIDICULA  (Ehr.).  —  Frustules  simple  or  binately  conjoined, 
free  or  adnate,  bivalved ;  central  portion  obsolete ;  valves  very  convex.  In 
Pyxidicula  the  frustule  forms  a  bivalved  box,  and  differs  from  CycloteUa  in  its 
vaulted  valves  and  the  absence  of  an  interstitial  portion.  The  same  characters 
distinguish  it  from  all  the  Coscinodiscea3.  As  fii'st  constituted  by  Ehrenberg, 
Pyxidicula  contained  very  heterogeneous  forms ;  by  the  formation,  however, 
of  ^lastogonia,  Stephanogonia,  Stephanopj-xis,  and  Xanthiop}'xis  as  distinct 
genera,  this  defect  has  been  in  a  great  measiu'e  removed ;  but  we  believe  it 
still  includes  some  doubtful  species.  Dictyopyxis  was  separated  by  Ehren- 
berg, first  as  a  subgenus  and  afterwards  as  a  genus,  for  those  forms  character- 
ized by  the  cellulose  structure  of  the  valves,  lea\-ing  in  the  original  genus  the 
smooth  and  punctated  sjiecies.  We  have  thought  it  more  desii^able  to  regard 
Dictj'opyxis  as  a  subgenus  only,  until  some  of  the  species  are  more  fnUy 
known. 


*  Frustules  smooth  or  mhmtdy  imnctcde. 
Pyxidicula. 

Pyxidicula  opcreulata  (E.).  —  Fru.>- 
tules  small,  orbicular,  hyaline,  punctated. 


EM.  pi.  16.  1.  f.  46.  =  P.  minor,  KSA. 
p.  21.  Fossil,  Sweden  ;  recent,  Asia,  Eng- 
land ?  Diam.  1-1440"  to  1-570".  Valves 
joined  by  a  distinct  suture.  Kiitzing 
refers  P.  "^operadata  (E.)  to  CycloteUa. 


OF  TKE  MELOSIREiE. 


825 


V.Adriatica  (Kiitz.). — Aduate,  sessile, 
of  middle  size ;  yalves  convex,  nearly 
hemispherical,  very  smooth.  KB.  t.  21. 
f.  8.  Adriatic,  (xiii.  33.)   Diam.  1-600". 

P.  ?  prcetexta  (E.). — Valves  geminate, 
slightly  hispid,  neither  cellulose  nor 
radiated,  but  bordered  by  a  raised  limb ; 
middle  tiat.  KSA.  p.  22,  Fossil.  Greece. 
Diam.  1-1152". 

P.  P  wceolaris  (E.). — Valves  geminate, 
unequal,  urceolate  (the  one  more  convex, 
elongated,  the  other  shorter),  each  with 
a  plane,  raised  limb ;  cellules  none,  but 
about  ten  smooth  rays  in  the  longer,  and 
eiglit  apiculate  ones  in  the  shorter  valve. 
=  Dktyopyxis  nrceohiris,  EM.  pi.  18.  f.  3. 
Fossil.    Virginia.     Diam.  1-1728". 

P.  lo/if/a  (E.).  —  Oblong,  two  and  a 
lialf  times  as  long  as  broad,  cylindrical, 
with  rounded  ends ;  suture  longitudinal. 
KSA.  p.  22.  Fossil.  Virginia.  L.  1-1080". 

2*  Frustules  cellulose.    Dictyopyxis  {E.). 

P.  cruciata  (E.).  —  Frustules  oblong, 
with  rounded  ends ;  cellules  large,  ar- 
ranged in  parallel  lines;  rim  distinct. 
EM.  pi.  18.  t".  2.=  Coscinodiscus  cruciatus, 
KSA.  p.  125. 

/3.  HelJe)iica,  smaller  =  DictyopyxisIIel- 
lenica,  EM.  pi.  19.  f.  13.  Fossil.  America. 
Guano,  &c.  Frequently  the  disk  has 
some  series  of  its  cellules  more  conspi- 
cuous and  forming  a  cross.  Valves  cani- 
panulate. 

P.  Cylindrits  (E.).  —  Cylindrical,  witli 
rounded  ends,  three  times  as  long  as 
broad  ;  valves  with  obscure  rows  of  cel- 
lules. E:M.  pi.  33.  13.  f.  8.  Fossil.  Maiy- 
land.  Diam.  1-9G0".  \alves  campanu- 
late,  separated  by  a  suture. 

P.  Lens  (E.).— Frustules  laterally  de- 
pressed, lenticidar,  cellulose ;  valves  in 
front  view  semielliptic.  EM.  pi.  18.  f.  5. 
Fossil.  Virginia.  Diam.  1-G3G".  The 
frustide  is  oval  in  the  front  view,  the 
euture  forming  the  greatest  diameter. 

P.  areolata  (E.).  —  Valves  with  a 
heptagonal,  areolate,  punctated  centre, 
and  seven  lateral  pmictated  areolae. 
KSA.  p.  22.   North  America.  D.  1-960". 

P.  gemmifera  (E.).  —  Valves  turgid, 
crystalline,  not  bordered,  furnished  with 
lax  series  of  crystalline  nodules,  fifteen 
of  which  \evj  nearly  reach  the  smooth 
centre.  KSA.  p.  22.  Fossil.  Maryland. 
Diam.  1-792". 

P.  compressa  (Bail.). — Frustules  ellip- 
tic, bivalve  ;  valves  separated  by  a  plane 
passing  through  the  longer  axis,  slightly 
convex,  and  with  transverse  rows  of  dots. 
BC.  ii.  p.  40,  f.  13,  14.     Florida. 

P.  dentata  (E.). — Frustides  having  the 


convex  margin  furnished  with  (irregular) 
slightly  prominent  little  teeth ;  cellules 
rather  "large,  6  in  1-1200".  KSA.  p.  22. 
Antarctic  Ocean.     Diam.  1-840". 

P.?  Umhata  (E.).  —  Frustules  oblong, 
with  a  central  keel ;  valves  showing  in 
front  a  central  celkdar  surface,  and  32 
to  40  radiating  lines;  border  not  cel- 
lidose.  =  Steijlianopyxis  Umhata,  EM. 
pi.  18.  f.  7.  Fossil.  Maryland.  D.  1-792". 
Ehrenberg's  figure  is  oval,  and  has  a 
broad,  distantly  striated,  but  not  cellu- 
lose rim,  and  in  its  centre  scattered  gi'a- 
nules. 

P.  cristata  (E.). — Frustules  with  gemi- 
nate, lenticular  valves,  which  are  close 
togetlier,  not  winged;  with  a  somewhat 
prominent  margin  like  a  thin  suture; 
cellules  of  disc  in  vows.  ~  Stejjhanojjyxis 
cristata,  EM.  pi.  18.  f.  6.  Fossil.  Vir- 
ginia. Diam.  1-816".  Ehrenberg's  figure 
somewhat  resembles  that  of  P.  Umhata ; 
but  the  cellules  of  the  oval  valve  are 
crowded,  and  the  striated  rim  is  nar- 
rower. 

Ohscure  or  doxihtful  Species. 

P.  XdyeUi  (Ktitz.). — Smooth,  one  side 
orbicular,  girt  with  a  membranous  wing- 
like ring ;  the  other  side  oval,  one  mar- 
gin more  convex,  umbonate  in  the  mid- 
dle.    KSA.  p.  889.     Switzerland. 

P.  Actinocyclus  (E.). — Frustules  with 
two  flattened,  finely  cellular  and  ele- 
gantly radiated  valves;  rays  30  to  40, 
straight  and  dense.  EM.  "pi.  18.  f.  19. 
=  Cyclotella  Actinocyclus,  KSA.  p.  20. 
Fossil.  America.  Diam.  1-720".  Ehren- 
berg  figures  only  the  lateral  view,  which 
in  its  radiating  series  of  dots  resembles  a 
Coscinodiscus. 

P.  Scarahceus  (E.).  —  Oblong,  with 
unequal  valves ;  when  viewed  laterally, 
recalling  the  figure  of  the  Scarabseus. 
=  Dictyopyxis  Scarahceus,  E.  Fossil. 
Virginia.  Diam.  1-648".  CeUides  14  in 
1-1150". 

P.  major  (Kiitz.).  —  Frustules  large, 
elliptic,  regLdarly  punctated.  IvB.  t.  1. 
f.  25.  North  America ;  France.  Diam. 
1-420".     Probably  a  state  of  P.  cruciata, 

P.  glohata.  —  \Ve  insert  under  this 
name  certain  spherical  bodies  of  a  dia- 
meter varying  from  1-240"  to  1-1150", 
discovered  in  1836  by  Ehrenberg  in 
fiints  near  Berlin,  and  considered  by  him 
to  belong  to  the  silicious  Diatomace^e. 
Kiitzing  has  examined  these  bodies, 
which  occur  along  with  silicious  spicida 
of  spono-es  and  species  of  Xanthidium 
and  Peridinium,  but  does  not  consider 
them  Pyxidiculae.    The  section  of  pebble 


826 


SYSTEMATIC  HISTORY  OF  THE  12^'FUSOEIA. 


containing  these  specimens,  from  wliicli 
Mr.  Bauer's  drawings  (xvii.  506-509) 
were  made,  was  found  on  Brighton 
beacli.  The  figures  are  magnified  100 
diameters. 

P.  prisca,  EM.  pi.  37.  7.  f.  5.     This 
species  is  found  in  fiints,  and  is  probably 


the  same  as  the  preceding. 

P.  ?  (jigas,  EM.  pi.  33. 13.  f.  18.  Fossil. 
California.  The  figure  shows  a  large 
orbicidar  disc,  with  distant  scattered 
dots,  and  no  suture. 

P.  decussata  (E.). — Foimd  in  the  chalk 
marl  of  ^gina. 


Genus  STEPHANOPYXIS  (Ehr.).— Enistiiles  simple  or  united  into  short 
filaments,  in  front  ^-iew  orbicular  or  oblong,  composed  of  two  cellulose  valves, 
each  having  a  crown  of  teeth,  spines,  or  membrane ;  central  portion  obsolete  ; 
lateral  view  circular.  "  This  group  includes  those  PyxidiculoB  which  have 
tui'gid  forms  with  a  cellular  sui'face,  bearing  in  the  middle  of  the  valves  a 
crown  of  small  teeth,  prickles,  or  a  membrane  "  (Bailey).  The  fossil  species 
appear  simple ;  but  as  recent  specimens  forming  short  filaments  have  been 
obtained  by  the  Eev.  R.  Cresswell  and  Mr.  Norman,  probably  the  others  also 
were  originally  so  formed,  but,  as  the  crowns  prevent  the  close  union  of  the 
frustules,  they  become  more  easily  disconnected.  The  valves  agree  in  their 
turgid  form,  rounded  ends,  and  cellulose  structures  with  Pyxidicula ;  but  their 
coronets  will  easily  distinguish  them. 


Stephanopyxis  Diaclema  (E.).  — 
Valves  hemispherical,  with  parallel, 
straight  rows  of  cellules ;  centre  of  disc 
depressed,  with  a  circlet  of  numerous 
teeth  (20  to  SO).  =  Pt/xidicuIa  Diadema, 
KSA.  p.  21.  Fossil.  Virginia ;  guano. 
Diam.  1-576".  We  have  seen  two  frus- 
tules connected. 

S.  Turris. — Frustides  cylindiical,  cel- 
lidose,  ends  depressed  at  the  centre  and 
fui-nished  with  a  crown  of  spines  or  pro- 
cesses, which  are  truncate  or  clavate  at 
their  apices ;  areolce  hexagonal,  7  in 
•001".=  CressivelUa  Turris,  Grey,  in  GDC. 
p.  64,  pi.  6.  f.  109.  In  stomach  of  Ascidia. 
Teignmouth,  Hull,  &c.  Fossil  in  guano. 
We  regret  being  unable  to  accept  the 
genus  Cresswellia,  as  we  believe  all  the 
species  of  Stephanopyxis,  when  recent, 
have  the  frustules  connected  by  their 
coronets :  S.  Diadema^  a  species  closely 
allied  to  the  present,  we  have  found  so 
united  in  specimens  from  guano.  This 
character  has  probably  escaped  detection 
only  because  in  all  filamentous  forms  the 
fossil  frustules  are  usually  separated. 
The  coronets  of  numerous  non-attenuated 
spines  distinguish  this  species,     (v.  74.) 

S.  apiculata  (E.). — Frustides  oblong 
or  subc^dindi'ical,  end  broadly  roimded ; 
cellules  not  crowded,  arranged  in  longi- 
tudinal rows )  centre  of  disc  with  a  few 


forming 


elongated  spines,  EM.   pi.  19.  13.  f.  G. 
America,  Europe,  guano,  ka. 

S.  appendiculata  (E.).  —  Frustides  in 
fi'ont  view  subglobose,  coarsely  and 
closely  cellidose ;  segments  with  rounded 
ends,  each  with  an  excentric,  short,  horn- 
like process.  EM.  pi.  18.  f.  4.  Fossil. 
Virginia.  Diam.  1-624".  Processes  trun- 
cate, not  central  j  cellules 
crenated  margin. 

S.  turglda  (Grev.). — Front  view  cylin- 
di'ical- oblong ;  junction-margins  subtrim- 
cate,  with  roimded  angles  and  a  crown 
of  elongated  spines  with  dilated  apices ; 
areolae  11  in  '001.  =  CressivelUa  turqida^ 
Grev  M J.  vii.  p.  165,  pi.  8.  f.  14.  Cali- 
fornian  guano.  This  species  is  nearly 
related  to  8.  Turris,  but  differs  in  the 
larger,  more  truly  cylindrical  and  trun- 
cate frustules,  and  in  the  considerably 
smaller  areolation,  Grev. 

S.  ferox  (Grev.). — Front  view  oblong ; 
valves  subglobose,  campanulate,  hispid, 
with  a  crown  of  elongated  spines  and  a 
thin,  hyaline,  prominent  suture ;  areolae 
large,  5  in  -001".  =  CressivelUa?  ferox, 
Grev  M J.  vii.  p.  166,  pi.  8.  f.  15, 16.  Ca- 
lifornian  guano.  The  valves  are  ex- 
panded at  their  junction  so  as  to  form 
a  sutm-al  keel,  as  in  some  species  of 
Pyxidicula.     (v.  75.) 


Genus  XANTHIOPYXIS  (Ehr.).— Valves  turgid,  continuous,  entire,  non- 
ceUulose,  hispid,  setose,  or  winged.  =  Pyxidicula  olim.  Fossil.  *'  These  forms 
are  Pyxidicula  with  bristles,  setse,  or  wdngs.  They  have  the  habit  of  Xan- 
thidium  and  Chtetotyphla,  but  are  bivalvcd  and  silicious."  The  true  affinity 
of  this  genus  is  doubtfril :  we  have  seen  no  species  which  is  circular  in  the 
lateral  view,  and  consequently  consider  them  misplaced  in  the  Melosirea) ; 


OF  THE  COSCINODISCE^. 


827 


but,  from  oui'  insufficient  acquaintance  with  them,  we  are  unable  to  decide  on 
their  proper  position,  and  have  not  attempted  their  removal.  Are  they  akin 
to  Goniothecium  ? 

Xanthiopyxis  glohosa  (E.).  —  Frus- 
tiiles  subglobose,  hispid,  with  short  setae. 
=  Pyxidicula  glohosa,  KS A.  p.  23.  Fossil. 
Bermuda.     Diam.  1-552". 

X.  ohlonga  (E.).  —  Frustiiles  oblong, 
equally  and  broadly  rounded  at  each  end, 
densely  hispid,  with  short  setae,  which 
are  sometimes  joined  by  a  membrane. 
EM.  pi.  33.  17.  f.  17.  =  Pyxidicula(K.). 
Fossil.  Virginia.  L.  1-552".     (v.  76.) 

X.  constricta  (E.). — Frustules  oblong, 
constricted  at  the  middle,  and  broadly 
rounded  at  each  end,  hispid,  with  short 
setae,  which  are  often  joined  by  mem- 
brane. =PJ/a^iV7^c?<^rt  constricta, }L^  A.,  p.  23. 
Fossil.  Bei-muda.  L.  1-384".  _  Ditfers 
from  X.  ohlonga  by  its  constriction. 

X.  hirsuta  (E.).  —  Frustules  bivalved, 
subglobose,  not  cellulose,  rough  with 
simple  and  obsoletely  forked  hairs.  = 
Pyxidicula  ?  hirsuta,  ERBA.  1845.  Fos- 
sil.    Maryland.     Diam.  1-115".     Habit 


of  Xanthidium,  but  silicious. 

X.  urceolaris  (E.). — Valve  urceolate, 
with  the  summit  bristly ;  margin  revo- 
lute.  EM.  pi.  33. 16.  f.  14.  Fossil.  Vir- 
ginia. Diam.  1-1560".  "  I  [EhrenbergJ 
have  only  met  with  single  valves.  In 
form  they  resemble  Stephanogonia,  but 
are  not  angular." 

X.  alata  (E.). — Frustules  smooth,  ob- 
long, each  end  equally  and  broadly 
rounded  ;  margin  of  the  valves  bordered 
by  a  lacerated  or  deeply  dentate,  not 
setose  membrane.  =  Pyxidicida  alata, 
KSA.p.23.  Fossil.  Bemmda.  D.  1-552"- 

Douhtfid  Diatom. 
X.  aculeata  (Ft.) = Pyxidicula  acideata. 
The  figure  in  Microg.  pi.  18.  f,  124  shows 
a  globular  spinous  body,  resembling 
some  sporangia  of  the  Desmidieae.  Eh- 
renberg  himself  regards  this  as  a  very 
doubtful  Diatom. 


Genus  INSILELLA  (Ehr.). — Frustules  simple,  equally  bivalved,  cylindrical 
(fusiform),  with  a  turgid  ring  interposed  in  the  middle  between  the  valves. 
Marine.     Eesembles  a  cylindrical  Biddulphia. 


Insilella  Africana  (E.). — Frustules 
fusiform,  smooth,  foiu"  times  constricted ; 
the  middle  joint  largest,  subglobose ;  the 


others  decreasing  at  each  end,  oblong; 
each  apex  acuminated.  KSA.  p.  32. 
Mouth  of  the  river  Zambese,  Africa. 


FAMILY  VIII.— COSCINODISCE^. 

Frustules  disciform,  mostly  simple ;  lateral  valves  or  discs  flat  or  convex, 
cellulose,  areolate  or  granulate,  without  processes,  but  sometimes  fui-nished 
wdth  spines  or  teeth ;  connecting  zone  ring-like  and  generally  smooth.  The 
Coscinodisceas  are  closely  allied  to  the  Melosirese, — a  fact  noticed  by  Kiitzing 
himself,  although  in  his  arrangement  the  families  are  widely  separated.  The 
distinction  between  them  is  by  no  means  satisfactory ;  according  to  Kiitzing, 
it  consists  in  the  cellulose  or  areolated  structure  of  the  Coscinodisceae.  But 
whilst  on  the  one  hand  we  find  in  the  Melosirese  some  species  of  Pyxidicula 
and  Stephanopyxis  with  cellulose  valves,  on  the  other  hand,  in  this  family 
some  species  are  merely  granulate  or  punctate.  Practically,  however,  the 
proper  situation  of  the  species  can  generally  be  determined  without  much 
difficulty.  In  the  Coscinodisceae  the  fi-ustules  never  form  filaments,  the  con- 
necting zone  is  always  present,  narrow  and  ring-like,  and  the  lateral  valves 
are  never  so  convex  as  to  be  hemispherical  or  campanulate ;  so  that  the  disk 
is  almost  always  in  the  field,  it  being  difficult  to  obtain  a  good  front  view. 
Most  of  the  forms  included  in  this  family  are  marine,  and  many  are  remark- 
able for  their  exceeding  beauty. 

Genus  COSCINODISCUS  (Ehr.).— Fmstules  simple,  discoid;  disc  ceUular 
or  dotted,  without  processes,  defined  border,  internal  septa,  or  division  into 
radiating  compartments.     ''  The  only  essential  character  that  distinguishes 


828 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


this  genus  from  Cj'clotcUa  is  the  areolation  of  the  secondary  surfaces" 
(Mencg.).  ^'  This  genus  finds  its  nearest  allies  in  the  Melosireae,  whose 
genera,  from  their  filamentous  character,  stand  widely  apart.  Were  the 
frustules  of  Coscinodiscus  eccentricus,  for  example,  permanently  coherent  after 
self- division,  it  would  be  difficult  to  separate  them,  in  a  generic  point  of 
"\iew,  from  those  of  OrtJiosira  nivalis,  which  have  the  same  cellular  structure, 
or  from  those  of  Melosira  aurichcdcea  or  M.  sulcata,  which  are  fiumished 
with  a  projecting  fringe  of  silex,  the  homologue  of  the  spinous  processes  in 
C.  eccentricus^'  (Smith,  BD.  i.  p.  23).  Coscinodiscus  is  easily  distinguished 
from  most  genera  in  this  family  by  a  disk  not  di^dded  into  compartments. 
In  the  greater  number  of  species  the  cellules  have  a  radiating  arrangement, 
and  become  smaller  near  the  margin ;  the  former  character,  however,  is  fre- 
quently obscure,  and  is  best  seen  by  as  low  a  magnifying  power  as  will  suffice 
to  determine  the  cellular  or  dotted  structure. 


*  Disc  ivith  a  few  centred  larger  {gene- 
redly  oblong)  celhdes,  steUeitely  eirranged, 
and  forming  an  umhiliccd  rosette  (^rim 
striated). 

t  Disc  large,  and  its  cellules  distinct. 

Coscinodiscus  centredis  (E.).  —  Cel- 
lides  minute,  nearly  equal,  in  crowded 
radiating  series;  umbilical  rosette  of  a 
few  oblong  celliiles  round  a  circular  one. 
EM.  pi.  18.  f.  39 ;  GDC.  p.  28,  pi.  3.  f.  50. 
Fossil.  Virginia  and  Sicily.  A  large 
species  with  striated  rim. 

C.  omplicdanthus  (E.).  —  Cellides  in 
radiating  series,  marginal  ones  smaller, 

7  to  8  in  1-1200",  middle  ones  larger, 
6  in  1-1200"  ;  umbilical  rosette  of  7  or 

8  large  oblong  cellules.  KSA.  p.  125. 
Bermuda  deposit.  Disc  large.  D.  1-96". 
Mr.  Briglitwell  finds  it  difficult  to  distin- 
guish this  species  from  the  foUowdng, 
and  considers  their  specific  characters 
unsatisfactory. 

C.  Oeidus  Iridis  (E.).  --Cellules  hex- 
agonal, in  radiating  series,  smaller  at 
the  margin  and  near  the  umbilical  rosette, 
which  is  formed  of  from  5  to  9  large 
oblong  cellules.  EM.  pi.  18.  f.  42.  Fossil 
and  recent.  America,  Europe,  Milford 
Haven,  &c.  This  large  species,  when 
dry,  is  marked  with  colom-ed  rings, — an 
effect  apparently  due  to  the  peculiar 
arrangement  of  its  cellules.  It  differs 
from  C.  centralis  in  its  larger  cellules, 
and  from  C.  asteromphcdus  by  the  absence 
of  a  veil.  ^' This  species,  both  in  the 
recent  and  fossil  specimens,  often  ac- 
quires a  size  not  much  inferior  to  that 
of  C.  gigas'^  (Bailey). 

"  C.  horealis  (Bail.).  — Disc  having  at 
its  depressed  centre  a  conspicuous  star, 
formed  of  about  6  large  cellides.  _  The 
rest  of  the  sm'face  covered  with  inter- 
ruptedly radiant  lines  of  prominent  hex- 


agonal ceUules,  which  increase  regularly 
from  near  the  centre  to  the  convex 
margin."  B.  in  Amer.  Jom-n.  of  Science 
and  Ai'ts,  1856.  Sea  of  Kamschatka. 
'■'  This  resembles  C.  Ocidus  Iridis ;  but 
the  cellules  forming  the  star  are  more 
rounded,  and  the  other  cellules  are 
larger  "  (Bailey). 

C.  asteromjjhalus  (E.).  —  Cellides  in 
radiating  series,  smaller  towards  the 
margin;  umbilical  rosette  distinct ;  sm- 
face  appearing  as  if  covered  bv  a  very 
finely  punctated  veil.  EM.  pi.  18.  f.  45. 
Fossil.  America.  Cellides  large,  rather 
tumid.  C.  asteromphalus  difters  from  the 
other  species  with  stellate  mnbilicus  by 
its  minutely  punctated  cellides. 

2 1  Disc  with  cellules  obscure,  and  re- 
quiring the  higher  magnifying  powers 
to  discern  them. 

C.  concinnus  (Sm.). — Disc  large,  with 
radiating  series  of  minute  puncta,  and 
an  umbilical  irregidar  rosette  of  larger 
cellules,  di\dded  into  compartments  by 
radiating  lines,  which  terminate  at  the 
margin  in  minute  spines,  (v.  89.)  SBD. 
ii.  p.  85;  Roper,  MJ.  vi.  p.  20,  pi.  3.  f.12. 
Europe.  Valves  convex.  In  some  spe- 
cimens the  markings  are  very  inconspi- 
cuous, and  difficidt  to  detect ;  in  others, 
as  in  the  specimens  from  Hidl,  moi'e 
evident. 

C.  stellaris  (Roper).  — Disc  extremely 
hyaline,  with  very  fine,  inconspicuous 
radiating  series  of  puncta,  and  a  few 
larger,  stellately  arranged  umbilical  cel- 
lides. (v.  83.)  RoMJ.  vi.  p.  21,  pi.  3. 
f.  3.  Caldy,  Pembrokeshire.  When 
mounted  in  balsam,  the  disc  is  so  hya- 
line, and  the  pimcta  so  difficult  to  detect, 
that  it  is  liable  to  be  regarded  as  a 
detached  ring.  Dry  valves  brownish, 
without  marginal  spines. 


OF  THE  COSCINODISCEiE. 


820 


2  *  Disc  tcith  a  central  hyaline  umhiUcuSy 
which  often  resembles  a  perforation. 
{The  species  are  commonly  smaller  than 
those  of  the  preceding  section.^ 

C.  actinochilus  (E,). — Granules  in  close 
lines,  radiating-  from  tlie  distinct  punc- 
tated umbilicus,  separated  from  the  mar- 
gin by  a  border  of  puucta  arranged  in 
close,  short,  radiating  lines.  EM. 
pi.  .35  A.  21.  f.  5.  Antarctic  Sea.  The 
radiatino-  series  of  granules  are  close, 
but  distinct. 

C.  ZuncB  (E.).  —  Granules  equal,  ar- 
ranged in  distinct  series,  radiating  from 
the  smooth  umbilicus,  and  separated  from 
the  margin  by  a  border  of  minute  pimcta. 
EM.  pi.  35  a.  21.  f.  7.  Antarctic  Sea. 
Somewhat  resembles  C.  actinochilus,  but 
has  fewer  rays,  the  marginal  puncta  are 
more  obscure,  and  the  umbilicus  is 
smooth. 

C.  gemmifer  (K.). — Disk  with  con- 
spicuous granules,  arranged  in  lax  and 
elegantly  radiating  lines  from  a  smooth 
umbilicus;  border  minutely  punctated. 
EM.  pi.  35  A.  22.  f.  3.  Antarctic  Sea. 
Bermuda  deposit.  The  rays  are  fewer 
and  more  distant  than  in  the  two  pre- 
ceding species ;  but  all  agree  in  having 
well-marked  grantdes,  distinct  rays,  and 
minute  submarginal  pimcta.  Diam. 
1-456".  Very  like  Pyxidicula  gemmifera, 
but  larger  and  more  depressed. 

C.  apiculatus  (E.).  —  Cellules  rather 
prominent,  apiculate,  rendering  the  sur- 
face rough,  subequal,  radiating,  10  in 
1-1200";'  umbilicus  smooth.  EM.  pi.  18. 
f.  43.  America.  Diam.  1-324".  Has 
a  general  resemblance  to  Pyxidicula 
gemmifera. 

C  ])erforatus  (E.).  —  Cellules  minute, 
arranged  in  close,  radiating  series ;  um- 
bilicus smooth,  resembling  a  perforation ; 
margin  finely  rayed.  EM.  pi.  18.  f.  46. 
America.  Diam."^  1-348".  Difiers  fr*om 
C.  fimhriatus  by  its  umbilicus. 

C.  disciger  (E.). — Differs  fr'om  C.  per- 
foratus  by  its  irregularly  circular,  not 
smooth,  and  larger  umbilicus,  and  by  its 
rery  minute  and  dense  punctiform  cel- 
lides.  KSA.  p.  123.  Virginia.  Diam. 
1-480".     Cellules  about  30' in  1-1200". 

C.  ApolUnis  (E.). — Disc  with  nume- 
rous series  of  very  dense,  equal,  puncti- 
form granules,  radiating  from  a  small 
umbilicus.  EM.  pi.  35  a.  22.  f.  4.  Ant- 
arctic Sea.  It  difiers  from  C,  Lunce  by 
the  gTeater  number  and  denseness  of  its 
rays,  which,  however,  although  nume- 
rous, are  distinct.  Diam,  1-432".  17 
granules  in  1-1200". 


Q.  cingulatus  (E.). — Disc  with  very 
dense,  pmictiform  granules,  indistinctly 
radiating  from  a  small  clear  umbilicus  ; 
margin  with  an  annular  band  capable  of 
being  detached.  EM.  pi.  35  a.  21.  f.  6. 
Fossil.  America,  Antarctic  Sea.  26  gra- 
nides  in  1-1200".  Diam.  1-552".  Resem- 
bles C.  Apollinis,  but  its  granules  are 
denser  and  less  distinctly  radiating. 

3*  No  ttmhilical  vacancy;  disc  tcith  a 
striated  border  distinct  from  the  rim. 

C.  Jimbriatus  (E.).  —  Cellules  small, 
subequal,  obsoletely  radiating,  near  the 
margin  smaller  and  arranged  in  radi- 
ating lines  resembling  strice.  E.  /.  c. 
pi.  22.  £  2.     Fossil.     Sicily. 

C.  7narginatus(E.). — Cellules  in  curved 
lines ;  marginal  ones  smaller  and  ar- 
ranged in  radiating  lines  resembling 
striae.  E.  /.  c.  pi.  18.  f.  44.  Recent  and 
fossil.  America,  Cuxhaven.  Cellules  9 
or  10  in  1-1200". 

C.  limbatus  (E.).  —  Central  cellides 
largest,  not  radiating,  outer  ones  small- 
est, crowded,  arranged  in  radiating  lines 
resembling  stride.  E.  /.  c.  pi.  20. 1.  f.  29. 
Fossil,  Greece.  Diam.  1-576",  The 
largest  7  in  1-1200". 

C.  striatus  (K.).  —  CeUides  irregularly 
crowded  in  the  middle ;  margin  of  disc 
with  radiating  strict.  KB.  t.  1.  f.  8. 
Cuxhaven.     Diam.  1-456". 

4  *  Disc  with  radiating  series  of  cellides ; 
no  distinct  umbilicus,  nor  striated  border 
distinct  from  the  rim. 

C.  gigas  (E.). — Disc  very  large  ;  cel- 
lules large,  hexagonal,  radiating,  largest 
at  the  margin,  decreasing  towards  the 
centre.  EM.  pi.  18.  f.  34.  Virginia  ; 
Maryland ;  alive,  Cuxhaven.  The  largest 
species  of  the  genus,  and  well  character- 
ized by  its  large  hexagonal  cellules  gra- 
dually decreasing  in  size  from  the  margin 
to  the  centre.     Rim  striated. 

C.  excavatus  (Grev.  MS.). — Disk  large, 
with  hexagonal  cellules  decreasing  in 
size  towards  the  centre,  which  has  three 
conspicuous  depressions  alternating  VNdth 
the  same  number  of  elevations.  Pisca- 
taway  deposit.  The  disc  in  this  species 
is,  from  its  large  size,  visible  to  the 
naked  eye,  and,  like  C.  gigas,  it  appears 
ring-like,  the  smaller  central  cells  being 
then  invisible.  There  is  no  distinct  um- 
bilicus ;  but  the  central  portion,  including 
the  elevations  and  depressions,  is  thinner 
and  is  rarely  foimd  perfect.  The  cellules 
of  the  depressions  appear  smaller  and 
more  radiant  than  the  others,  (yth.  26.) 


830 


SYSTEMATIC  mSTORY  OF  THE  INFFSOEIA, 


C.  crassiis  (Bail.).  —  Disc  without  a 
central  star,  covered  ^\dth  iiiteiTiiptecUy 
radiant  lines  of  large,  prominent,  hex- 
agonal cellules  wdth  circidar  pores ',  cel- 
lules somewhat  larger  near  the  maro;in. 

B.  Amer.  Jom-n.  Science,  1856.     Alive, 
Sea  of  Kamtschatka ;  fossil,  Monterey. 

C.  profundus  (E.). — Cellules  of  disc 
subequal,  near  the  margin  smaller  and 
irregidarlv  radiating.  ERBA.1854j  EM. 
pi.  35  B.  f.  8.     Atlantic. 

C.  radiatus  (E.).  —  Cellules  rather 
large,  arranged  in  radiating  lines  (EM. 
pi.  21.  f.  1;  SBD.  pi.  3.  f.  37),  smaller 
near  the  margin,  (xi.  39,  40.)  Common, 
both  recent  and  fossil.  Diam.  1-860"  to 
1-240".  The  radiating  arrangement  is 
sometimes  obscure. 

C.  Sol  (WaUich).— Disc  as  in  C.  radi- 
atus, but  surrounded  by  a  broad,  hyaline, 
membranous  border,  which  is  divided 
into  compartments  bv numerous  radiating 
lines.  Wallich,  TMS.  viii.  pi.  2.  f.  1,  2. 
From  Salpae,  Bay  of  Bengal,  and  Indian 
Ocean.  On  subjecting  the  frustule  to 
acids,  the  membranous  ring  is  at  first 
simply  detached,  and  after  a  while  dis- 
solved (WaUich). 

C.  Argus  (E.). — CeUides  large,  some- 
what smaller  at  the  centre  and  margin  j 
the  radiating  aiTangement  often  inter- 
rupted. EM.  pi.  21.  f.  2.  Eecent,  Cux- 
haven ;  fossil,  Oran  and  Sicily.  May  be 
a  variety  of  C.  radiatus,  from  which,  how- 
ever, Mr.  Brightwell  considers  it  suffi- 
ciently distinct.  He  finds  the  cellules 
in  that  species  always  radiant,  whilst 
in  the  present  they  have  no  definite 
an*angement. 

C.  radiolatus  (E.). — Granules  puncti- 
form,  equal,  radiating.  E.  /.  c.  pi.  18. 
f.  36.      Fossil,  Virginia.      Differs   from 

C.  Apollinis  bv  the  absence  of  an  um- 
bilicus.    18  ceUules  in  1-1200". 

C.  suhtiUs  (E.). — Granules  punctiform, 
small,  equal,  radiating.  E.  /.  c.  pi.  18. 
f.  35.  America.  Similar  to  C.  radiolatus, 
but  with  24  cellules  in  1-1200". 

C.  Normaimi  (Greg.). — Disc  with  ra- 
diating series  of  faint  areolae  arranged 
in  fasciculi  of  about  6  rows  each ;  areolae 
equal,  except  near  the  margin,  where 
they  are  smaller;  rim  smooth.  Grev 
MJ.  vii.  p.  81,  pi.  6.  f.  3.  In  stomach  of 
Ascidians.  Hull.  Areolae  about  24  in 
•001".  No  distinct  umbilicus.  Differs 
from  C.  subtilis  by  having  only  half  as 
many  lines  in  each  fascicidus  (Grev.). 

C.  punctafus  (E.). — Cellules  puncti- 
fonn,  radiating,  loosely  disposed  at  the 
centre,  very  densely  crowded  at  the 
margin,  and  forming  a  broad,  yellowish- 


white  border, 
;  p.  124 


Vii'ginia. 


EM.  pi.  18.  f.  41 ;  KSA. 

Collides  at  centre, 
24  to  26  in  1-1200".  Diam.  1-348". 
j  Ehrenberg  gives  a  figm'e  of  an  oval 
I  variety  of  this  species,  pi.  18.  f.  40. 
j  C.  ienellus  (E.). — Cellules  very  small, 
equal,  radiating.  EB.  1854.  Atlantic. 
j  17  or  18  ceUules  in  1-1200".  The  cha- 
j  racters  given  are  insufficient  to  distin- 
I  guish  this  species  fi'om  C.  radiolatus  and 
j  C.  subtilis. 

I      C.  gramdatus  (E.). — Disc  small,  with 
I  dense  series  of  very  small  cellules,  caus- 
ing a  gTanidar  appearance ;  granides  18 
to  21  in  1-1152".    KSA.  p.  122.    FossU. 
Virginia.     Diam.  1-552". 

C.  umhonatus  (Greg.).  —  Disc  densely 
cellulate,  ha\'ing  a  broad,  nearly  flat 
marginal  zone,  the  central  portion  being 
nearly  or  quite  hemispherical ;  cellules 
generally  radiant,  small  and  irregular  in 
outline.  Diam.  -0045".  Lamlash  Bay. 
GD.  p.  28,  pi.  2.  f.  48. 

5  *  CeUules  tiot  radiating ;  no  distinct 
wnhilicus  or  striated  border, 

t  Cellules  aiTanged  in  more  or  less 
perfect  concentric  circles. 

C.  Patina  (E.).  —  Disc  large,  with 
moderate-sized  cellules,  disposed  in 
concentric  circles  and  becoming  smaller 
towards  the  margin.  KB.  p.  1.  f.  15. 
Fossil,  Greece;  alive,  Cuxhaven.  The 
young  and  vigorous  specimens  of  live 
indiAdduals  are  completely  filled  with 
yellow  granides,  whilst  the  older  ones 
have  an  in-egular  -s'ellow  granular  mass 
within  them.     Diam.  1-860"  to  1-240". 

C.  isojjorus  (E.). — Disc  coarsely  cel- 
lular; cellules  close,  arranged  in  con- 
centric circles.  EM.  pi.  33.  17.  f.  3. 
Disc  of  moderate  size.  Ehrenberg's 
figure  bears  some  resemblance  to  C.  con- 
cavus,  but  has  concentric  ceUides,  and  no 
distinct  rim. 

C.  velatus  (E. ).  —  Cellules  large,  an- 
gidar,  rather  distant,  arranged  somewhat 
concentrically;  the  disc  punctated,  ap- 
pearing as  if  "^covered  with  a  veil.  E.  /.  c. 
pi.  18.  f.  37.     Virginia.     Diam.  1-492". 

2 1  Cellules  in  parallel  or  cur\'ed  lines. 

C.  lineatus  (E.).  —  Cellules  small,  cir- 
cular, arranged  in  straight,  parallel  lines. 
KB.  pi.  1.  f.  10.  Fossil,  Sicily  and  Ame- 
rica; alive,  Cuxhaven.  Common.  The 
cells  in  this  species  form  parallel  lines  in 
whatever  direction  they  may  be  viewed. 
In  large  and  well-preserved  fossil  speci- 
mens as  many  as  twenty-five  openings 
(?  spines)  were  seen  near  the  circum- 


OF  THE  COSCINODISCE.^::. 


831 


fereuce.  AVithiu  the  live  forms  some- 
times mmieroiis  yellow  vesicles  are  seen, 
as  in  Gallionella.  Diameter  of  fossil 
1-1150"  to  1-480";  living,  1-1150"  to 
1-8G0". 

C.  eccentricns  (E.).  —  Cellules  small, 
disposed  in  excentric  curved  lines.  KB. 
pi,  1.  f.  9.  Common,  both  recent  and 
fossil.     D.  1-860  to  1-430  '. 

3t  Cellules  in  no  determinate  arrange- 
ment. 

C.  concavus  (E.).  —  Each  valve  very 
concave,  the  two  opposite  conjoined, 
forming  an  entire,  A'eiy  convex  body ; 
cellides  coarse,  equal,  not  radiating. 
EM.  pi.  18.  f.  38;  GDC.  pi.  2.  f.  47. 
Virginia.  Cellules  4  in  1-1200".  An 
Afi'ican  variety  has  twice  as  many.  = 
Melosira  cribrosa,  Sm  ANH.  xix.  p.  11, 
pi.  2.  f.  15. 

C.  heteroporus  (E.).  —  Cellules  hex- 
agonal, smaller  at  the  margin  and  centre, 
intermediate  ones  largest,  imequal.  KA. 
p.  123.  Beimuda  deposit.  D.  1-360". 
This  species  may  be  recognized  by  the 
smaller  marginal  and  central  cellules  and 
the  very  imequal  intermediate  ones. 

C.  minutus  (Kiitz.).  —  Disc  nearly 
smooth,  margin  with  punctated  rays. 
D.  1-1416".  KB.  1. 1.  f.  14.    CuxhaveA. 

C.  minor  (E.). --Margin  smooth ;  disc 
irregularly  and  densely  celluloso-punc- 
tate.  Fossil,  Sicily  and  Virginia ;  alive, 
Europe  and  America.  E.  /.  c.  Not  C. 
mifior  of  SBD. 

C.  Jlavicans  (E.).  —  Disc  small,  with 
very  fine  non-radiating  cellules,  yellow 
by  transmitted,  but  white  by  reflected 
light.  KSA.  p.  122.  Peru  and  St.  Do- 
mingo. 

C.  labyrinthus  (Roper). — Disc  divided 


by  dotted  lines  into  large,  irregular,  hex- 
agonal, minutelv  dotted  spaces ;  puncta 
15  in  -001".  Pto'MJ.  \d.  p.  21,  pL  3.  f.  2. 
Pembrokeshu-e.  This  species  has  some- 
what the  aspect,  under  a  low  power,  of 
a  finely  marked  specimen  of  C.  eccen- 
tricns, but  difters  in  the  absence  of  a 
spinous  margin,  and  in  the  large  and 
irregularly  shaped  hexagonal  spaces 
^vdthout  any  clearly  defined  margin  (Ro.). 

Doubtful  or  imperfectly  hioivn  Sjiecies. 
C.  cinctus   (K.).  —  Rim  with   inter- 
rupted radiating  strise;   cellules  of  disc 
crowded  in  the  centre,  the  others  scat- 
tered, remote.    KSA.  p.  122.     C.  Patina, 

B.  AJmer.  Jour,  of  Science  and  Arts, 
1842,  pi.  2.  _f.  13.  Alive,  Cuxhaven; 
fossU;  Virginia.  Diam.  1-324".  Ehren- 
berg  refers  the  Virginian  specimens  to 

C.  minor. 

C.  oralis  (Ro.). — Valves  oval,  brown- 
ish in  balsam,  with  finely-dotted  radi- 
ating lines  and  no  distinct  imibilicus. 
Ro  MJ.  vi.  p.  22,  pi.  3.  f.  4.  Pembroke- 
shire. Markings  very  delicate  and  in- 
conspicuous,     (v.  78.) 

C.  punctulatus  (Greg.). — Disc  marked 
with  very  fhie  and  obsciu-e  lines,  the 
whole  surface  sparsely  punctate.  Lam- 
lash  Bay.     GD.  p.  28,  pi.  2.  f.  46. 

C.  nitidus  (Greg.). — Disc  marked  with 
distant  and  irregularly  radiant  granules, 
larger  towards  the  centre ;  margin  striate, 
striae  about  16  in  -001".  Lainlash  Bav. 
Greg.  /.  c.  p.  27,  pi.  2.  f.  45.    (viii.  18.)' 

C.  cervinus  (Bri.).  —  Disc  minutely 
punctate,  pimcta  scattered  ;  centre  con- 
vex. Diam.  -0054"  to  ■0086".  =  B:i/alo- 
cliscus  cervinus,  Bri  J31S.  viii.  p.  95,  pi.  5. 
f.  9.     Arctic  regions. 


G^iiTis  ENDICTYA  (Ehr.). — Fnistiiles  dLsciform,  simple  or  forming  short 
filaments,  closely  ceUulose,  in  front  view  with  a  middle  furrow,  having  on 
each  side  crowded  parallel  series  of  cellules.  Kiitzing  places  its  only  species  in 
Coseitiodiscus ;  but  we  think  that  it  is  much  more  nearly  allied  to  Orthosira. 

Endictya  oceanica  (E.).  —  Disc  with 
close  cellules  and  a  dentate  rim.  (v.  70.) 
EM.  pi.  35  A.  18.  f.  6,  7.  =  Orthosira  oce- 
anica, Bri  JMS.  viii.  p.  96,  pi.  6.  f.  16. 
Common  in  Peruvian  guano.      Some- 


times the  cellules  of  the  disc  are  almost 
concentric  in  their  arrangement,  7  in 
1-1152".  Diam.  1-528".  This^  form  is 
probably  identical  with  Coscinodiscus 
concavus  and  Melosira  cribrosa. 


Genus  CRASPEDODISCUS  (Ehr.).  —  Fnistules  simple,  disciform;  disc 
cellulose,  Tvdthout  striae  or  septa,  but  having  a  broad,  well-defined,  tumid 
border  of  a  diflferent  structure  from  the  centre.  Craspedodiscus  has  the  habit 
of  Coscinodiscus,  with  which  Kiitzing  united  it.  It  diff'ers  from  Coscinodiscus 
Umhatus,  and  similar  forms,  by  its  margin,  which  does  not  form  a  mere  rim, 
but  a  broad  border  of  a  dififereut  structiu?e,  separated  from  the  centre  by  a 
distinct  furrow  or  well-defined  line. 


832 


SYSTEMATIC  niSTORY  OF  THE  IXFITSOEIA. 


Craspedodiscus  elcf/am  (E.). — Bor- 
der with  obliquely  quadrate  cellules; 
disc  with  a  central  rosette  of  hve  or  six 
oblong  ones,  the  others  being-  circular 
and  somewhat  radiating-,  (xi.  38.)  EM. 
pi,  33.  18.  f.  2.  =  Cosci)iocNscus  eler/ans, 
KSA.  p.  126.  Bermuda  deposit.  Frus- 
tules  large,  with  an  elegantly  marked 
border,  the  diameter  of  which  is  much 
less  than  that  of  the  centre.  This  species 
difters  from  the  rest  in  its  central  rosette 
and  diagonally  marked  border. 

C.  Coscinodiscus  (E.). — Border  broad, 
but  of  less  diameter  than  the  centre  ; 
cellules  of  border  large,  close ;  those  of 
centre  minute  or  puncta-like,  and  scat- 
tered. _  (v.  80.)  _  EM.  pi.  35.  16.  f.  8.= 
Pyxidicula  Coscinodiscus,  EB.  1844  ;  Cos- 
cinodiscus Pi/xidicula,  KSA.  p.  126;  Br 
JMS.viii.p.9o,pl.5.  f.4.  Fossil.  United 
States. 

C.  microdiscus  (E.).  —  Border  very 
broad,  its  diameter  greater  tlian  that  of 
the  centre ;  cellules  of  border  large,  close; 
those  of  centre  minute,  scattered.  E.  /.  c. 
pi.  33.  17.  f.  4.    Fossil.    United  States. 


Resembles  C.  Coscinodiscus,  from  which 
it  ditiers  in  its  proportionally  smaller 
centre. 

Doubtful  Sjjecies. 

C.  ?  Stella,  EM.  pi.  3o  b.  b.  4.  f.  11. 
Ehrenberg's  figure  represents  a  smootli 
disc  with  a  Melosira-like  umbilicus,  from 
which  radiate  irregularly  placed  lines. 

C.  ?  Franldini,  EM.  pi.  35  a.  23.  f.  6. 
=  Hyalodiscus  suhtilis. 

C  inarginatus  (Bri.). — Disc  with  hya- 
line margin,  having  about  20  rays ;  re- 
mainder of  the  valve  minutely  punctate. 
Diam.  -0037".  Barbadoes  deposit.  Ih- 
JMS.  viii.  p.  95,  pi.  5.  f.  7. 

C.  semiplanus  (Bri.).  —  Margin  very 
broad,  faintly  radiate  and  punctate.  One 
half  of  central  part  of  the  valve  smooth, 
the  remainder  with  4  or  5  radii.  Diam. 
•0024"  to  -0035".  Barbadoes  deposit. 
Br.  I.  c.  p.  95,  pi.  5.  f.  12. 

C.  coronatus  (Bri.). — Only  fragments 
of  this  form  have  hitherto  been  found, 
and  consequently  no  satisfactory  specific 
character  can  be  given.  Br.  /.  c.  p.  95.  f.  6. 


Genus  ODONTODISCUS  (Ehr.).— Fmstules  simple,  orbicular  ;  disc  with- 
out nodule  or  septa,  but  with  dotted  rays  and  erect  teeth.  Odontodiscus 
differs  from  Coscinodiscus  and  Actinocyclus  by  having  its  disc  furnished  with 
teeth,  of  which  the  others  are  destitute.  The  dots  are  radiate,  not  parallel, 
as  in  Systephania. 


Odontodiscus  Spica  (E.).  —  Teeth 
submarginal,  numerous  (48) ;  granules 
in  radiating  series.  ILA..  p.  129.  Fossil. 
Virginia.     Granules  19  in  1-1152". 

O.  Uranus  (E. ). — Disc  with  numerous 
(32)  radiating  series  of  granules  and 
marginal  teeth.  KSA.  p.  129.  Fossil.  Vir- 
ginia. O.  Uranus  has  marginal  teeth  and 
fewer  radiating  series  of  granides  than 
O.  Spica ;  but  we  doubt  whether  they  be 
really  distinct  species. 

O.  eccentricus  (E.).  —  Disc  with  its 
granules  arranged  in  eccentric,  curved, 
indistinctly  radiating  rows ;  teeth  nu- 


merous, marginal,  (v.  90.)  EM.  pi  36  a. 
18.  f.  \\.=  Coscinodiscus  eccentricus,  SD. 
i.  p.  23,  pi.  3.  f.  38.  ?  Fossil.  Guano,  &c. 
Granules  about  20  in  1-1152".  D.  1-864". 
This  species  difters  from  Coscinodiscus 
only  in  having  teeth,  and  may  be  merely 
that  state  of  the  latter  which  is  described 
and  figured  by  Professor  Smith  as  spinous. 
We,  however,  have  generally  failed  to 
detect  the  spines  in  the  Coscinodiscus 
eccentricus,  although  they  are  obvious 
enough  in  the  Odontodiscus,  which  is 
usually  much  smaller.  On  these  accounts 
we  cannot  decide  that  they  are  identical. 


Genus  SYSTEPHANIA  (Ehr.).  —  Frustules  orbicular;  disc  cellulose, 
neither  radiate  nor  septate,  with  an  external  circlet  of  spines  or  an  erect 
membrane  on  the  disc,  not  on  the  margin ;  cellules  in  parallel  rows.  ''  The 
genus  has  the  habit  of  Coscinodiscus  lineatus,  but  with  lateral  crowns,  which, 
in  the  young  state,  unite  two  individuals  "  (Bailey).  The  spines  are  subulate, 
and  appear  not  unlike  the  peristome  of  a  moss. 


Systephania  acideata  (E.).  —  Disc 
loosely  cellulose ;  cellides  distinct,  spines 
erect,  not  crowded,  few  (12  to  15),  placed 
on  the  disc  near  the  margin.  KA.  p.  126. 
Bermuda.  Cellules  8  in  1-1152".  Diam. 
1-324".      This  species   is  distinguished 


by  its  fewer  spines  and  more  conspicuous 
cellules. 

S.  Corona  (E.).  —  Disc  densely  cellu- 
lose ;  spines  erect,  numerous  (40  to  50), 
closely  set,  placed  on  the  margin.  EM. 
pi.  33.  15.   f.  22.      Bermuda,   Virginia. 


OF  THE  COSCINODISCE.E. 


833 


Cellules  12  in  1-1152".  Diam.  1-348". 
The  spines  are  far  more  numerous  and  the 
cellules  less  distinct  than  in  S.  aculeata. 

S.  Diadema  (E.). — Disc  densely  cellu- 
lose ;  spines  numerous,  marginal,  in- 
cm-ved,  conjoined  at  their  extremities 


by  a  membrane.     EM.  pi.  33.  18.  f.  11. 

Bermuda.  Cellules  14  in  1-1152".  Diam. 
1-864".  Much  smaller  than  the  two 
preceding  species.  All  have  a  variable 
number  of  teeth. 


Genus  SYMBOLOPHORA  (Ehr.).  —  rmstules  orbicular,  not  concatenate; 
disc  with  striae  or  dotted  lines,  radiating  from  a  solid  angular  centre.  Sym- 
Ijolophora  differs  from  Actinocyclus  in  having  an  angular  or  steUate  hyaline 
centre. 

Ehrenberg  has  placed  in  this  genus  forms  which  agree  only  in  their  hyaline 
angular  umbilicus ;  and  the  species  with  radiating  series  of  dots  scarcely 
differ  from  Coscinodiscus. 


Symbolophotia  Trinitatis  (E.). — Disc 
having  a  triangular  crystalline  umbilicus 
with  a  crenated  margin,  from  which 
radiate  six  fascicles  of  very  fine  lines 
diverging  towards  the  margin.  EB. 
1844,  p.  88.  (XI.  36.)  Fossil.  Maryland. 
We  believe  no  one  except  Ehrenberg 
has  observed  this  species,  for  which  the 
genus  was  constituted ;  and  it  has  been 
suggested  that  his  figure  may  represent 
what  he  erroneously  supposed  to  be  the 
original  form  (as  shown  by  a  fragment) 
of  Triceratimn  Marylandka ;  but  in  this 
opinion  we  cannot  concur,  because  in 
several  instances  where  Ehrenberg  has 
founded  species  on  mere  fraginents  he 
has  figiu'ed  the  fragments  as  he  observed 


;  them,  Mdthout  attempting  a  restoration 

i  of  their  supposed  entire  figm-e. 

I       S.  acutangida  (E.).  —  Resembles  the 

I  preceding  in  size  and  habit,  but  has  the 

i  angles  of  its  umbilicus  acute.   EB.  1845, 

i  p.  81.     Fossil.    Virginia. 

1      S.  ?  Microtrias   (E.).  —  Disc  tm-gid, 

I  with  a  stellate  umbilicus,  from  which 

radiate  series  of  pimcta.  Antarctic  Ocean. 

Umbilicus  triradiate  =  S.  3Iicrotnas,  E. 

/.  c.  1844,  p.  205  ;  EM.  pi.  35  a.  21.  f.  16. 

Umbilicus    cruciate  or   fom'-rayed  =  S. 

Tetras,  E.  I.  c.    Umbilicus  five-rayed = /SI 

Pentas,  EM.  pi.  35  a.  22.  f.  19.  Umbilicus 

six-rayed  =  S.  Hexas,  E.  I.  c.  This  species 

differs  from  a  Coscinodiscus  only  in  the 

presence  of  the  stellate  umbilicus. 


Genus  HETEE,0STEPHA:NTA  (Ehr.).— Characters  lmkno^vn  to  us. 


Heteeostephania  RotJiii,  EM.  pi. 
35  A.  13  B.  f.  4,  5.  (v.  85.)  _  Elbe.  Disc 
with  radiating  series  of  minute  puncta. 


8  or  10  marginal  teeth  or  minute  pro- 
cesses, and  no  umbilicus.  Front  view 
with  minute,  erect,  marginal  teeth. 


Genus  HALION'YX  (Ehr.). —  Frustules  orbicular,  not  concatenate;  disc 
rayed ;  number  of  rays  definite,  not  starting  from  the  umbilicus  ;  no  internal 
septa.  It  resembles  Actinocyclus,  except  in  its  umbilicus  not  being  radiate ; 
or,  in  other  words,  its  central  ocellus  is  wanting.  In  Hke  manner  Coscino- 
discus differs  from  Symbolophora  in  its  non-radiate  umbilicus,  which  is  a 
simple  void  space. 


Halionyx  senarius  (E.). — Surface  of 
disc  wdth  six  rays ;  each  compartment 
is  marked  by  parallel  lines,  which  de- 
crease by  equal  gradations  on  either  side 
of  a  radiating  median  line  ;  loosely  and 
widely  cellulose  ;  umbilicus  entire,  punc- 
tated. KA.  p.  130.  Antarctic  Ocean. 
Diam.  1-720".  Approaches  Actmoptychus 
undulatus. 


H.  undenarius  (E.). — Disc  with  eleven 
or  twelve  rays ;  umbilicus  large,  punc- 
tated, not  radiant,  (v.  82.)  EM.  pi  35  a. 
21.  f.  12.  =  ^.  duodenarius,  E.  olim.  Ant- 
arctic Ocean.  Diam.  1-576".  Ehrenberg'a 
figure  shows  the  disc  with  a  granulated 
centre,  from  which  proceed  radiating 
series  of  puncta  and  eleven  darker  or 
shade -like  rays. 


Genus  ACTINOCYCLUS  (Ehr.). — Frustules  simple,  disciform;  disc  mi- 
nutely and  densely  punctated  or  cellulose,  generally  divided  by  radiating  single 
or  double  dotted  lines,  and  having  a  small  circular  hyaline  intramarginal 
pseudo-nodule.     We  consider  Actinocyclus,  as  limited  by  Ehrenberg,  a  well- 

3h 


834 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


marked  genus.  Its  confusion  has  arisen  from  Professor  Kiitzing's  retention 
in  it  of  some  species  of  Actinoptychus,  and  the  application  of  its  name 
by  Professor  Smith  to  the  latter  genus.  The  disc  is  not  undulated;  and 
the  rays,  which  are  often  very  indistinct,  are  dotted  or  interrupted,  not 
continuous  lines.  From  the  minute  size  and  close  arrangement  of  the  puncta, 
the  frustules,  when  mounted  in  Canada  balsam,  never  appear  hyaline,  but  of 
a  brownish  or,  more  frequently,  of  a  beautiful  purplish  colour.  The  disc  is 
furnished  with  an  intramarginal  pseudo-nodule,  which  simulates  an  orifice. 
Ehrenberg  in  this,  as  in  other  genera  of  Diatomaceee,  distinguished  his  species 
solely  by  the  number  of  their  rays ;  but  we  cannot  retain  them,  as  we  con- 
sider species  foimded  on  such  characters  altogether  unscientific  and  erroneous. 
In  general,  names  once  bestowed  ought  to  be  retained,  even  when  somewhat 
inappropriate  or  defective,  because  less  injury  is  done  by  their  retention  than 
by  burdening  the  science  with  synonyms ;  still  we  believe  it  far  better  to 
bestow  a  new  name  when,  as  in  this  genus,  numerous  species  are  reduced  to 
one  to  which  the  original  names  would  be  inapplicable. 


AcTiNOCYCLUS  moniliformis(\\.  sp.). — 
Disc  divided  into  compartments  by  three 
or  more  rays,  formed  of  single  series  of 
dots,  in  a  moniliform  arrangement.  =  ^. 
^erwarmSjEM.  pl.22.  f.  9.  Fossil.  Europe, 
Africa,  and  America.  This  species  in- 
cludes most  of  Ehrenberg's  figures  of 
Actinocycli  from  the  deposits  of  Greece, 
Oran,  Sicily,  and  Virginia  (pis.  18,  19,  21 
&  22).  We  have  seen  no  specimens ;  but 
in  Ehrenberg's  figures  the  single  monili- 
form rays  difier  so  greatly  from  what  we 
find  in  the  following  species  that  we 
must  consider  them  distinct,  although 
Ehrenberg,  in  consequence  of  his  regard- 
ing the  number  of  the  rays  as  the  essen- 
tial character,  has  mixed  up  its  forms 
with  those  of  the  following  species  under 
the  same  names. 

A.  Ehrenherfiil  (n.  sp.).  —  Disc  gene- 
rally iridescent,  closely  punctated,  so  as 
under  a  low  power  to  appear  waved, 
divided  by  regular  equidistant  rays 
formed  of  interrupted  double  lines,  which 
terminate  at  the  margm  in  minute  teeth. 
Common,  both  recent  and  fossil.  Very 
fine  in  Icliaboe  guano.  Under  this  name 
we  include  all  Ehrenberg's  species  with 
rays  composed  of  double  lines.  The  rim 
is  narrow,  but  generally  distinct ;  pseudo- 
nodule  minute.  In  fluid,  A.  Hhrenhergii 
is  colourless ;  but  when  momited  in  bal- 
sam, it,  like  the  next  species,  varies  with 
different  shades  of  brown,  green,  blue, 
purple,  and  red.  The  rays  are  formed 
by  lines  composed  of  linear  or  subidate 
hyaline  spaces,  which,  more  frequently 
than  in  A.  Rcdfsii,  are  in  pairs,  though 
sometimes  alternate  ;  they  are  often  in- 
distinct, especially  in  smaller  specimens. 
This  species  is  best  recognized  by  the 
waved  appearance  of  its  puncta. 

We  subjoin  a  list  of  forms  included  in 


A.  Ehrenhergii,  but  by  Ehrenberg  re- 
garded as  distinct  species.  Most  of  them 
may  be  obtained  from  Ichaboe  guano. 
We  imite  them  all  in  this  species : — 
A.  ternariiis,  3  rays ;  A.  quatejmarius,  4 ; 
A.  quinarius,  5  5  A.  hiternarins,  6 ;  A. 
septeyiarius,  7  ;  A,  octonarius,  8 ;  A.  no- 
narius,  9 ;  A.  denarius,  10 ;  A.  undena- 
rius,  11 ;  A.  bisenariuSf  12 ;  A.  tt'edena- 
rius,  IS;  A.  hiseptenarms,  14;  A.  quin- 
deuanus,  15 ;  A.  hioctonarius,  16 ;  A. 
septemdenariiis,  17  ;  A.  hinonarius,  18 ; 
A.  tioi'emdenarius,  19 ;  A.  vicenarius,  20 ; 
A.  Lima,  21 :  A.  Ceres,  22 ;  A.  Juno,  23 ; 
A.  Jupiter,  24 ;  A.  3fars,  25 ;  A.  Mer- 
curius,  26  ;  A.  Pallas,  27 ;  A.  Saturnus, 
28;  A.  Terra,  29;  A.  Venus,  30;  A. 
Vesta,  31;  A.  Uranus,  32;  A.  Achar- 
neus,  33 ;  A.  Aldeharan,  34 ;  A.  Antares, 
35  ;  A.  Aquila,  36 ;  A.  Arcturus,  37  ;  A. 
Bet-el-c/ose,  38  ;  A.  Canopus,  39 :  A.  Ca- 
pella,  40 ;  A.  Fom-el-hot,  41 ;  A.  Lyra, 
42 ;  A.  Procyon,  43 ;  A.  Requlus,  44 ;  A. 
Rigl,  45 ;  A.  Sirius,  46 ;  A.  Sol,  47 ;  A. 
A.  Spica,  48;  A.  Stella  2)olaris,  49;  A. 
Ninus,  50;  A.  Alexander,  51;  A.  Ptole- 
mcsus,  52;  A.  Davides,  53;  A.  Numa, 
54  ;  A.  Croesus,  55  ;  A.  Dux,  56 ;  A.  Rex, 
57 ;  A.  Imperator,  58  ;  A.  Plutus,  59  ; 
A.  Proserpina,  60 ;  A.  ahundans,  61 ;  A. 
luxuriosus,  62  ;  A.  prodigus,  63  ;  A.  for- 
tunatus,  64  ;  A.  locuples,  65 ;  A.  opiparus, 
66 ;  A.  pretiosus,  67 ;  A.  poly  act  is,  68 ; 
A.  magmyicus,  69 ;  A.  Zoroaster,  70 ;  A. 
Solon,  71 ;  A.  Cleohulus,  72 ;  A.  Chilo, 
73 ;  A.  Pittacvs,  74 ;  A.  Thales,  75 ;  A, 
Bias,  76  ;  A.  Periander,  77  ;  A.  Socrates, 
78;  A.  Salomo}!,  79;  A.  Homerus,  80; 
A.  Hesiodus,  81;  A.  Tyrtmis,  82;  A. 
Anacreon,  83;  A.  Sappho,  84;  A.  Pin- 
darus,  85  ;  A.  JEschylus,  86 ;  A.  Sophocles, 
87;  A.  Euripides,  88:  A.  Virgilius,  89; 
A.  Horafius,  90 :   A.  Tuhehain,  91 ;  A. 


OF  THE  COSCINODISCEiE. 


835 


Dcedalm,  92;  A.  CalUmachus,  93;  A. 
Phidias,  94 ;  A.  Praxiteles,  95 ;  A.  Pyr- 
goteles,  96  ;  A.  Apelles,  97 ;  A.  Zeiixis, 
98;  A.  Orjyheus,  99 ;  A.  Apollo,  100; 
A.  Adamas,  101 ;  A.  Achates,  102  ;  A. 
Amethi/stus,  103  ;  A.  Astrolites,  104  ; 
A.  Benjllus,  105 ;  A.  Carhunculus,  106 ; 
A.  Chrysolithus,  107 ;  A.  Hyacinthus, 
108 ;  A.  laspis,  109 ;  A.  lasponyx,  110  ; 
J[.  Leucochrysus,  111 ;  ^.  Omphus,  112  ; 
^.  0/2?/j7,  li3;  A.  Opalus,  114;  ^.  ^Sa- 
phirus,  115;  ^.  Sarda,  116;  ^.  Sardonyx, 
117;  ^.  Smaragdus,  118;  ^4.  Topazius, 
119 ;  ^.  Panheiios,  120. 

A.  Ralfsii  (Sm.).  —  Disc  iridescent, 
with  close  radiating  series  of  punctiform 
granules,  interrupted  bv  numerous  subu- 
late hyaline  spaces,  which  are  crowded 
in  the  centre  and  more  distant  near  the 
margin,  where  they  form  irregular  rays  of 
doujjle  broken  lines  ;  marginal  teeth  and 
pseudo-nodule  as  in  A.  Ehrenheryii.  = 
Eupodiscus  Ralfsii,  SBD.  ii.  p.  86.  British 
coast,  (v.  84.)  3.  sparsus  (Greg,  in  lit.), 
granules  in  loose  series,  without  angular 
blanks,  the  principal  rays  alone  reaching 
the  umbilicus,  =  Eupodiscus  sparsus,  Greg 
TMS.  V.  p.  81,  pi.  1.  f.  47  :  Scotland. 
"  The  lines  of  cellules  diminish  in  num- 
ber at  distinct  intervals  from  the  margin 
towards  the  centre  of  the  valve,  giving 
a  zoned  appearance  when  seen  under  a 
low  power  "  (SBD.).  A.  Ralfsii  differs 
from  A.  Ehrenheryii  in  the  radiated  ar- 
rangement of  its  granules,  the  far  greater 
number  of  hyaline  spaces,  and  the  more 
irregular  distribution  of  the  rays,  in 
which  also  the  blank  spaces  in  the  asso- 
ciated lines  are  usually  alternate.  The 
following  remarks  on  the  var.  sparsus 
are  condensed  from  Professor  Gregory's 
papers  :  —  Principal  rays  equidistant, 
formed  of  large  dots  not  closely  set ; 
between  the  principal  rays,  the  inner 
ends  of  which  leave  a  small  central  imi- 
bilicus,  occur  shorter  series  parallel  to 
each^other,  the  middle  one  longest,  the 
others  progressively  decreasing  in  length 
on  each  side,  and  the  shortest  adjacent 
to  the  principal  rays,  which  they  approach 
at  an  angle.  Professor  Gregoiy  finds  the 
same  arrangement  in  A.  Ralfsii;  but  in 
that  form  the  dots  are  large  and  very 
close.  In  A.  Ralfsii  the  colom-  varies 
with  different  shades  of  purple,  blue, 
green,  and  yellow,  and  sometimes  brown 
or  buff.  At  Professor  Gregory's  sug- 
gestion, we  reduce  A.  sparsus  to  the  rank 
of  a  variety,  as  he  finds  the  species  to 
vary  much  in  the  size  of  the  granules,  in 
their  closeness,  and  in  colour. 

A.  fulvus  (Sm.). — ''Cellular  sti'ucture 


indistinct,  radiate;  colour  of  dry  valve 
towny.''^  =  Eupodiscus  fulvus,  SBD.  i. 
p.  24,"^  pi.  4.  f  40.  Britain.  Rays  obscure. 
We  doubt  whether  this  species  be  distinct 
from  A.  Ehrenheryii,  many  specimens  of 
which  have  very  indistinct  rays. 

A.  crassus  (Sm.).  —  Disc  somewhat 
opaque,  purplish  when  dry ;  granules  in 
radiating  series ;  pseudo-nodule  as  in  A. 
Ralfsii;  margin  smooth.  =  Eupodiscus 
crassus,  SBD.  i.  p.  24,  pi.  4.  f.  41.  Britain. 
Mr.  T.  West  believes  this  species  to  be 
an  immature  state  of  A.  Ralfsii. 

Douhtful  Species. 

A.  Panheiios  (E.). — Very  large;  disc 
with  120  very  fine  rays.  KSA.  p.  128. 
Cuxhaven.     Diam.  1-180". 

*  Disc  yenerally  coloured,  furnished  with 
radiating  series  of  puncta. 

A.  interpunctatus  (Bri.).  —  Disc  with 
an  indefinite  number  of  double  rays 
running  from  the  centre  to  near  the  cir- 
cumference ;  the  rays  composed  of  short, 
broken  lines;  the  spaces  between  the 
rays  are  minutely  punctate.  California, 
New  Zealand,  West  Indies.  =  Actino- 
ptyclms  interpunctatus,  Bri  JMS.  viii. 
p.  94,  pi.  6.  f.  17. 

A.  suhtilis  (Greg.). — Disc  very  hyaline, 
with  numerous  very  fine  inconspicuous 
radiating  dotted  lines,  a  circular  punc- 
tated umbilicus,  and  rather  distant  mar- 
ginal teeth.  =  Eupodiscus  suhtilis,  GDC. 
p.  29,  pi.  3.  f.  50.  Forming  brown  patches 
on  aides  of  rocks,  llfracombe,  Plymouth. 
This  species  is  easily  distinguished  by 
its  hyaline  appearance  in  balsam.  The 
pseudo-nodule  is  minute,  radiating  lines 
indistinct,  and  the  umbilicus  is  furnished 
with  scattered  dots  surrounded  by  a 
dotted  circle.  Frustules  sometimes  con- 
tained in  an  indefinite  mucous  stratum. 

2*  Disktcith  hexayonal  cellules,  which 
are  not  in  radiating  lines. 

A.  tessellatus  (Ro.).  —  Cellules  of  disc 
distinct,  hexagonal,  with  a  minute  no- 
dule at  each  angle,  not  radiant.  =  Eupo- 
discus tessellatus,  Ro  JMS.  vi.  p.  19,  pi.  3. 
f  1.  Pembrokeshire,  Hull,  Norfolk. 
Guano.  This  species  is  placed  in  Acti- 
nocyclus  because  of  its  solitary  intramar- 
ginal  pseudo-nodule ;  but  in  its  structure 
it  differs  so  much  from  the  other  species 
of  that  genus,  that  it  might  be  separated 
from  it.  The  reticulated  disc  and  ab- 
sence of  rays  distinguish  it.  In  balsam 
it  is  nearly  colourless. 

3h2 


836 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Genus  ASTEROLAMPRA  (Ehr.).— Frustules  simple,  disciform ;  disc  orbi- 
cular, with  marginal  areolated  or  punctated  compartments,  separated  by 
smooth  rays  which  proceed  from  a  hyaline  central  area ;  central  area  divided 
by  lines,  which  radiate  from  the  umbilicus  to  the  apex  of  each  compartment ; 
compartments  and  rays  symmetrical.  Marine.  The  disc  in  this  beautiful 
genus  is  generally  colourless,  and  when  mounted  in  balsam  is  far  from  con- 
spicuous, notwithstanding  its  comparatively  large  size.  The  marginal  com- 
partments are  usually  conical,  and  from  the  apex  of  each  a  line  or  rib  proceeds 
to  the  umbilicus.  The  hyaline  central  area  seems  to  originate  from  the  dilated 
inner  ends  of  the  rays,  and  its  lines  to  be  produced  by  their  jimction.  Aste- 
rolampra  is  distinguished  from  Asteromphalus  by  the  compartments  being 
similar  and  equidistant ;  on  which  account  the  rays  are  equal,  the  lines  all 
radiant,  and  the  umbilicus  central. 


*  Umbilical  lines  straight. 

AsTEROLAMPEA  Manjhmdica  (E.).  — 
Umbilical  lines  simple,  straight;  areo- 
lated compartments  conical  or  semicir- 
cular. EB.  1844,  p.  76,  f.  10 ;  Wallich, 
TM.  viii.  p.  47,  pi.  2.  f.  13,  14;  GrevTM. 
viii.  p.  108,  pi.  3.  f  1-4:.=  A.  septenaria, 
Johns.  Sill.  Journ.  2ud  ser.  xiii.  p.  33 ; 
A.  impar,  Sh  TM.  ii.  pi.  1.  f  14 ;  A.  pe- 
lagica,  EB.  1854,  p.  238.  Fossil,  Vir- 
ginia :  Monterey  stone,  guano.  Recent, 
India,  &c.  (xi.  33.)  Rays  6  to  14.  The 
disc  varies  greatly,  not  only  in  the  num- 
ber of  rays,  but  in  the  elongated  or  de- 
pressed form  of  the  compartments,  pro- 
ducing a  corresponding  variation  in  the 
size  of  the  central  area. 

A.  Rotala  (Grev.).  —  Resembles  A. 
Marylandica,  but  the  areolated  compart- 
ments have  subtruncate  apices ;  umbili- 
cal lines  straight.  GrevTM.  viii.  p.  Ill, 
pi.  3.  i.  5.  Monterey  stone.  Umbilical 
lines  simple  or  dividing  in  a  forked  man- 
ner, close  to  the  central  point. 

A.  variahilis  (Grev.). — Compartments 


with  cuneate  apices  ;  umbilical  lines 
straight,  mostly  united  in  twos  or  threes 
near  the  central  point.  Grev  TM.  viii. 
p.  Ill,  pi.  3.  f.  ^^.  Monterey  stone. 
Rays  6  to  11. 

A.  Grevillii  (Wallich,  Grev.).  —  Com- 
partments conical,  with  truncated  apices ; 
umbilical  lines  straight,  variously  united. 
^=  Asteromphalus  Grevillii,^ si]\  TM.  viii. 
p.  47,  pi.  2.  f.  15  5  Asterolampra  Grevillii, 
GrevTM.  viii.  p.  113,  pi.  4.  £  21.  Fossil, 
Viro-inia  and  Monterey  stone ;  recent, 
Indian  Ocean.  This  species  approaches 
Asteromphalus  in  the  appearance  of  the 
central  area,  but  its  marginal  compart- 
ments and  alternating  rays  are  symme- 
trical.    Rays  numerous,  13  to  17. 

2  *  Umbilical  lines  angularly  bent. 

A.  Brebissoniana  (Grev.). — Areolated 
compartments  trmicated ;  umbilical  lines 
with  an  angular  bend  in  the  middle. 
Grev  TM.  viii.  p.  114,  pi.  3.  f  9.  Mon- 
terey stone.  Umbilical  lines  simple  or 
united,  close  to  the  central  point. 


Genus  ASTEROMPHALUS  (Ehr.).— Frustules  simple,  disciform  ;  chsc  as  in 
Asterolampra,  but  \^-ith  two  of  the  punctated  compartments  approximate,  and 
the  interposed  ray  narrower  than  the  others.  Marine.  Asteromphalus  differs 
from  Asterolampra  in  having  two  compartments  closer  together.  The  lines 
connecting  these  with  the  umbilicus  do  not  radiate  like  the  rest ;  and  the 
enclosed  hyaline  ray  consequently  differs  in  form  from  the  others,  and  is 
termed  the  median  or  basal  ray. 


*  Umhilical  lines  radiating  frorn  a  central 
point,  two  of  them  approximated.  As- 
teromphalus. 

t  Umbilical  lines  straight  or  curved. 

Asteromphalus  Hooherii  (E.). — 
Punctated  compartments,  conical  or 
rounded  at  the  apex ;  umbilical  lines 
straight,  the  median  ones  parallel.  EB. 
1844,  p.  200;  EM.  pi.  35  a.  21.  f.  2.  =A. 


Buchii,  EB.  1844,  p.  200;  A.  Humboldtii, 
E.  /.  c.  p.  200 ;  EM.  pi.  35  a.  21.  f  3 ;  J. 
Cuvierii,  EB.  1844,  p.  200 ;  EM.  pi.  35  a. 
21.  f  1.  Antarctic  Ocean.  (xf34.)  Rays 
6  to  9.  A\'e  consider  that  forms  differing 
only  in  the  nmnber  of  their  rays  are  not 
really  distinct,  and  have  consequently 
united  Ehrenberg's  species  quoted  above. 
A,  Dallasianus  (Grev.).  —  Areolated 
compartments,  with  truncate  apices ;  me- 
dian lines  campanulate.  =  Asterolampra 


OF  THE  COSCINODISCEJE. 


837 


Dallastana,  Grev  TM.  viii.  p.  115,  pi.  4. 
f.  10.     Bermuda,  Tripoli. 

A.  Wallichianus  (Gfrev.).  —  Areolated 
compartments,  with  truncate  apices  ; 
mnbilical  lines  straight.  =  Asterolampra 
Widlichiana,  Grev  TM.  viii.  p.  115,  pi.  4. 
f.  11.  Bermuda,  Tripoli.  ''  Tlie  umbilical 
portion  of  each  ray  is  so  wide  next  the 
areolated  segments,  that  it  may  be  com- 
pared to  a  short-bladed  trowel,  while 
the  linear  part  represents  the  handle  " 
(Grev.).  According  to  Dr.  Greville's 
figure,  this  species  differs  from  Astero- 
lampra only  by  its  median  ray  being 
narrower  than  the  rest. 

2 1  Umbilical  lines  with  an  angular 
bend. 

A.  Beamnontii  (E.).  —  Compartments 
with  rounded  apices  ;  umbilical  lines 
with  an  angular  bend ;  median  ones 
straight,  parallel.  EB.  1844,  p.  200,  f.  5  5 
Grev  TM.  viii.  p.  115.     Antarctic  Ocean. 

A.  Darwinu  (E.).  —  Compartments 
with  rounded  or  subtruncate  apices ; 
umbilical  lines  with  an  angular  bend; 
median  ones  bent  or  cm*ved.  ERBA, 
1844,  p.  200,  f.  I.  =  Asterolampra  Uar- 
winii,  Grev  TM.  viii.  p.  116,  pi.  4.  f.  12, 
13  ;  AsteromphalusRossii,  ERBA.  p.  200, 
f.  2;  EM.  pi.  35  a.  21.  f.  4.  Antarctic 
Ocean,  Monterey  stone,    (v.  86.) 

2*  Disc  suhcircular,  rays  unequal;  um- 
bilical lines  radiating  from  the  top  and 
sides  of  the  median  ones,  which  latter 
pass  beyond  and  enclose  the  central 
point.     Spatangidiimi. 

t  Umbilical  lines  not  bent. 

A.  jiabellatus  (Breb.,  Grev.).  —  Punc- 
tated compartments,  conic  ;  umbilical 
lines  straight  or  slightly  curved,  radi- 
ating from  apex  and  sides  of  the  median 
ones.  Grev M J.  vii.  p.  160,  pi.  7.  f.  4,  5.  = 
Spatangidiiimjlabellatum,  Breb.  Bull.  Soc. 
Linn,  de  Normand.  iii.  pi.  3.  f.  3  ;  Aste- 
rolampra Jlabellata^  GrevTM.  viii.  p.  116 ; 
Spatangidiimi  peltatuni,  Breb.  /.  c.  pi.  3. 
f.  4.  Peruvian  and  Californian  guanos. 
Rays  10  or  11 ;  median  one  clavate ; 
areolation  of  compartments  very  minute. 

A.  Hiltonianus  (Grev.).  —  Punctated 
compartments  naiTowly  conic ;  umbilical 
lines  radiating  from  apex  and  sides  of 
median  line's,  the  two  lower  pair  sud- 
denly (ii&^es.Q^.=  Asterolampra  Hiltoni- 
ana,  GrevTM.  viii.  p.  117,  pi.  4.  f.  15. 
Algoa  Bay  guano,  Indian  Ocean.  Rays 
10  to  19,  slender ;  umbilical  lines  simple 
or  forked ;  areolation  very  minute.     It  is 


a   very  transparent   species,  and   easily 
overlooked,  Grev. 

A.  Arachne  (Breb.).  —  Disc  broadly 
ovate ;  hyaline  area  small  and  excentri- 
cal;  areolated  compartments,  very  un- 
equal ;  umbilical  lines  straight,  short  j 
dilated  head  of  median  ray  truncate.  = 
iSjxitangidium  Arachne,  Breb.  Bull.  Soc. 
Linn,  de  Normand.  iii.  pi.  3.  f.  1 ;  Aste- 
rolampra Arachne,  Grev  TM.  viii.  p.  123 ; 
Asteromphalus  malleus,  Wall  TM.  viii. 
p.  47,  pi.  2.  f.  11 ;  Excentron  cancroides, 
Ralfs  in  lit.  (v.  66.)  Peruvian  guano, 
Indian  Ocean.  Distinguished  by  its  mal- 
leiform  median  ray.  Compartments  with 
large  areolation ;  umbilical  lines  less  con- 
spicuous than  in  the  other  species.  Rays 
usually  5,  sometimes  7 ;  median  and 
adjacent  ones  straight,  the  anterior  pair 
curved.  When  there  are  only  hve  rays, 
this  species  differs  greatly  in  appearance 
from  the  rest  by  having  the  anterior 
margin  of  the  head  of  the  median  ray  in 
direct  contact  with  the  anterior  com- 
partment; but  when  the  rays  are  7  in 
number,  the  hyaline  dilated  portions  of 
the  anterior  pair  interpose  between  these 
parts,  as  in  the  other  species. 

2 1  Umbilical  lines  with  an  angidar 
bend. 

A.  elegans  (Grev.).  —  Punctated  com- 
partments, conic,  more  than  half  the 
radius ;  umbilical  lines  with  an  angular 
bend,  radiating  from  apex  and  sides  of 
the  median  ones,  usually  simple,  but 
sometimes  two  or  three  united.  Grev 
MJ.  vii.  p.  7,  pi.  7.  f.  6.  =  Asterolampra 
elegans,  MJ.  viii.  p.  118,  pi.  4.  f.  16.  Ca- 
lifornian guano,  Indian  Ocean,  (v.  87. ) 
Areolation  extremely  minute ;  rays  13  to 
29,  gracefully  slender. 

A.  imbricatiis  (Wall.).  —  Areolated 
compartments,  conic,  less  than  half  the 
radius;  rays  numerous,  robust;  angidar 
bends  of  umbilical  lines  forming  unitedly 
an  oblong-elliptical  figure.  Wall  TM. 
viii.  p.  46,  pi.  2.  f.  ^.  =  Asterolampra  im- 
bricata,  Grev  MJ.  viii.  p.  119,  pi.  4.  f.  17. 
Indian  Ocean,  Natal.  Areolation  con- 
siderably larger  than  in  A.  elegans,  its 
nearest  ally,  Grev. 

A.  Brookei  (Bail.). — Disc  almost  cir- 
cular ;  areolation  conspicuous ;  compart- 
ments truncated;  angular  bend  of  um- 
bilical Imes  near  the  outer  end  ;  umbilical 
portion  of  median  ray  constricted  be- 
neath the  rounded  inner  end,  then  dilated. 
Bail.  Sill.  Journ.  2  ser.  xxii.  p.  2,  pi.  1.  f.  1. 
=  Asterolampra  Brookei,  Grev  MJ.  viii. 
p.  119,  pi.  4.  f.  18.  Soundings,  Kamt- 
schatka,  Atlantic,     (v.  79.)     The  uuibi- 


838 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


lical  lines  radiate  from  the  upper  half 
of  the  median  ones,  and  are  sometimes 
divided.  The  angular  bend  is  nearer  the 
outer  end  than  in  any  other  species ;  and 
at  each  angle  is  a  minute  spine-like  pro- 
cess, Grev. 

A.  Roper ianus  (Grev.). — Disc  circular, 
with  its  hyaline  area  centrical ;  areolated 
compartments,  truncate,  almost  equal ; 
umbilical  lines  radiant  from  rovmded 
end  of  median  ones ;  median  lines  pass- 
ing round  the  central  point  in  a  semi- 
circle, then  contracted,  and  lastly  widely 
expanded.  =  Asterolamjva  Roperiana, 
Grev  M J.  \i\\.  p.  120,  pi.  4.  f.  14.  Indian 
Ocean.  Rays  7,  robust ;  areolation  rather 
large,  Grev. 

A.  ShadhoUianus  (Grev.). — Areolated 
compartments,  truncate ;  umbilical  lines 
radiant  from  the  pyriform  median  ones, 
with  the  bend  about  the  middle ;  rays 
not  reaching  the  \\\?iT:^m.=Asterolampra 
Shadboltiana,  Grev  MJ.  viii.  p.  121,  pi.  4. 
f.  19.  Indian  Ocean.  ''  Rays  7,  robust ; 
areolation  rather  large.  Its  nearest  ally 
is  perhaps  A.  Brookei,  from  which  it  is 
separated  by  the  very  diflerent  median 
lines  and  by  the  angular  bend  being 
more  in  their  middle"  (Grev.).  Dr. 
Greville  suspects  that  in  this  species,  as 
in  A.  Roperiaims,  A.  heptactis,  and  A. 
Arachie,  the  number  of  rays  may  be 
more  constant  than  is  generally  the  case 
in  the  group. 

A.  heptactis  (Breb.). — Areolated  com- 
partments, truncate )  rays  broad,  linear, 
terminating  in  a  lunate  marginal  fold, 
and  bordered  by  a  row  of  larger  areolae. 
=  Spatangidium  heptactis,  Breb.  Bull.  Soc. 
Linn,  de  Normand.  iii.  p.  3.  f.  2 ;  Aste- 
rolampra  heptactis,  Grev  TM.  viii.  p.  122 ; 
Spatangidium  Ralfsianum,  TM.  vii.  p.  161, 
pi.  7.  f.  7,  8.  Peru\dan  and  Californian 
guanos,  Atlantic  soundings.  Rays  7, 
straight  or  slightly  curved,  the  median 
one  in  a  broad  shallow  groove,  the  linear 
portion  faintly  prolonged  through  the 
dilated  portion  to  spurs  fi'om  the  bends 
of  the  adjacent  umbilical  lines.  Areo- 
lation of  compartments,  conspicuous; 
disc  subcircular.     (-^tii.  21.) 

Doubtful  or  imperfectly  described 
Species. 
A.  centr aster  (Johnston). — Disc  orbi- 
cular ;    areolated    compartments     with 


i  roimded  apices  and  bordered  by  a  series 
j  of  larger  areolae  ;  umbilical  lines  straight, 
I  radiating  from  top  and  sides  of  median 
I  ones ;  rays  terminating  at  the  margin  in 
j  nodules.   Johnston,  MJ.  viii.  p.  12,  pi.  1. 
f.  10.      Elide  guano,    (viii.  14.)      Rays 
11.      Dr.  Johnston's  figure  diflers  from 
eveiy  known  species  by  having  the  rays 
continued,  as  Dr.  Greville  remarks,  like 
distinct  bars  or  the  ribs  of  an  umbrella, 
from  the  central  point  to  the  margin. 
We  believe,  however,  that  this  structure 
is  similar  to  what  is  met  with  in  several 
other  species  of  Asterolampra  and  As- 
teromphalus    (see    especially  Gre-vdlle's 
figures    of  Asterolampra    variabilis,   A. 
Wcdlichiami,  A.  Roperiana,  and  A.  hep- 
tactis), but  more  strongly  marked,  and 
probably  exaggerated  in  the  figure. 

A.  stellatus  (Grev.).  =  Asterolampra 
stellata,  Grev  TM.  viii.  p.  124,  pi.  4.  f.  20. 
Indian  Ocean.  It  is  allied  to  A.  Hilto- 
nianus  and  A.  JlaheUatus.  The  lowest 
pair  of  umbilical  lines  are  cm*ved  down- 
wards, as  in  the  former  species.  The 
median  lines  are  parallel.  The  valve, 
at  a  first  glance,  is  most  conspicuous  for 
the  large  size  of  the  hyaline  area  and  the 
rapidly  attenuated  rays;  but  this  may 
prove  to  be  a  worthless  distinction. 

A.  Sarcophagus  (Wall.).  —  Valve  ob- 
long, with  inflated  middle ;  median  ray 
plane  and  continuous  with  the  anterior 
rav ;  umbilical  lines  straight ;  areolation 
very  large.  Wallich,  TM.  viii.  p.  47,  pi.  2. 
f.  V2.=i  Asterolampra  Sarcophagus,  Grev 
TM.  viii.  p.  124.  Indian  Ocean.  "  The 
broadest  portion  of  this  species  is  always 
towards  the  extremity  opposite  to  the 
median  ray,  thus  gi\-ing  the  valve  a  some- 
what p^a'iform  or  sarcophagus-like  shape" 
(Wallich).  "  The  form  of  ihQ  valve  is 
so  extreme  a  deviation  from  the  other- 
wise more  or  less  orbicular  shape  of  the 
entire  series,  that  an  impression  almost 
forces  itself  upon  the  mind  tJiat  it  is 
simply  a  malformation.  It  is  most  nearly 
related  to  A.  Ai-achne ;  for  if  we  remove 
the  terminal  ray  (which  in  many  species 
may  be  either  absent  or  present),  the  five 
remaining  rays  would  occupy  the  relative 
position  M^hich  they  hold  in  that  species, 
as  well  as  in  the  same  direction,  one  pair 
pointing  upwards,  the  other  pair  down- 
wards. In  both  species  the  areolation  is 
large"  (Grev.). 


Genus  ASTERODISCIJS  (Johnson).  —  Frustules  simple,  disciform;  disc 
divided  into  punctated  compartments,  which  do  not  reach  the  centre,  by  hyaline 
smooth  rays ;  compartments  connected  to  the  umbilicus  by  an  equal  number 
of  radiating  lines,  two  united  half  way,  the  rest  distinct.     Fossil.     (Johnson, 


OF  THE  COSCINODISCE^ , 


839 


in  Silliman's  Amer.  Joiirn.  1852.)  "  The  proximate  genera^  Asterolampra 
and  Asteromphalus,  are  readily  distinguished.  In  the  former,  all  the  connect- 
ing hnes  are  symmetrical;  in  the  latter,  two  are  parallel;"  whilst  in  this 
genus  one  line  divides  half-way  from  the  centre  and  proceeds  to  two  of  the 
compartments,  the  smooth  ray  between  which  is  smaller  than  the  others,  but 
not  parallel  as  in  Asteromphalus. 


AsTERODiscus  JohisonH.  — Kays  and 
mnbilical  divisions  from  five  to  nine. 
Bermuda  earth.  This  includes  the  fol- 
loAviiig  species  of  Johnson : — 

A.  quinarius. — Marginal  rays  and  um- 
bilical divisions  five. 

A.  senarius. 
bilical  divisions  six. 


-Marginal  rays  and  um- 


A.  nonarius. — Marginal  rays  and  um- 
bilical divisions  nine. 

"  Front  view  bi-convex  ;  compart- 
ments elegantly  marked  with  minute 
dots,  arranged  in  excentric  cmwes '' 
(Johnson). 


Genus  ACTIXOPTYCHUS  (Ehr.).— Frustules  disciform,  ceUulose ;  disc 
divided  into  equal  triangiilar  compartments  by  lines  or  internal  septa  (E.). 
=  Actinocyclus,  Smith,  not  Ehr.  The  circular  disc  is  cellulose,  and  divided 
into  triangular  portions  by  lines  (''  internal  septa,"  E.)  radiating  from  its 
centre.  The  alternate  portions  are  usually  more  distinct,  owing  to  the  undu- 
lated form  of  the  frustules,  which  causes  them  alternately  to  be  nearer  to  or 
more  remote  from  the  eye.  The  apparent  septa  distinguish  it  from  Actino- 
cyclus, and  the  absence  of  spines  from  Heliopelta  and  Omphalopelta.  We 
have  not  the  slightest  doubt  that  Ehrenberg  has  properly  separated  Actino- 
cyclus from  Actinoptychus.  Professor  Smith  himself  practically  admits  this, 
by  placing  the  groups  in  different  genera,  although  he  has  not  retained  the 
names  as  affixed  by  their  author.  If,  however,  the  validity  of  their  separa- 
tion be  admitted,  the  founder  of  these  genera  has  surely  an  undoubted  right 
to  retain  the  original  name  for  whichever  group  he  thinks  fit.  Professor 
Smith  seems  to  have  erred  by  choosing  as  the  type  of  Actinocyclus,  not  one 
of  Ehrenberg' s  species,  but  a  form  placed  in  that  genus  by  Professor  Kiitzing, 
though  really  belonging  to  Actinoptychus. 

AcTixoPTYCHUS  temcinus  (E.).  —  j  and  minutely  punctate^  and  which  has 
Disc  with  3  or  5  radiating  lines,  -^dth-  j  been  described  as  a  new  species  by  Mr. 
out  a  distinct  umbilicus ;  compartments    "  " 

even.  KB.  pi.  1.  f.  19.  =^.  quinarius,  E. 
Fossil.  Virginia.  The  rays  proceed 
directly  to  its  centre,  without  leaving  an 
umbilical  space. 

A.  unduhtus  (Kiitz.). — Disc  with  its 
compartments  alternately  prominent  and 
cellulose  and  depressed  and  punctate; 
umbilicus  indistinct  or  indefinite.  = 
Actinocyclus  unduhdus,  KB.  pi.  1.  f.  24  ; 
Actinoptyclms  hiternarius,  EM.  pi.  18. 
f.  20 ;  A.  hiternatus,  EM.  pi.  35  a.  16.  f.  1. 
(v.  88.)'  America.  Guano,  &c.  Com- 
partments six  or  more. 

A.  velatus  (E.).  —  Compartments  six, 
loosely  ceUulose  ;  surface  apparently 
covered  by  a  thin  pimctated  membrane. 
KSA.  p.  130.  Virginia.  We  are  imac- 
quainted  with  this  species,  but  think  it 
may  probably  be  a  state  of  A.  undulatus, 
the  valves  of  which  frequently  consist 


Roper  in  TM.  vi.  p.  23  {Actinocyclus  tri- 
radiatus),  who  first  observed  it  detached 
from  the  true  valve.  He  and  others 
have  since  found  the  plates  in  situ. 

A.  senarius  (E.).  —  Compartments  (6 
or  more)  alternately  prominent,  all 
loosely  celhdose  ;  umbilicus  angular, 
definite  ;  rim  striated.  EM.  various 
plates.  =  Actinocyclus  tindulatus,  SB.  i. 
pi.  5.  f.  43.  (IX.  132.)  Common,  both 
recent  and  fossil.  Mr.  Tuffen  West  re- 
gards A.  senarius  and  Omplialopdta  areo- 
lata  as  identical.  The  presence  of  mar- 
ginal spines  in  the  latter  seems  indeed 
the  only  essential  distinction;  and  we 
have  generally  succeeded  in  detecting- 
spines,  more  or  less  distinct,  exactly 
such  as  Professor  Smith  has  represented 
in  one  of  the  figures  of  his  Actinocyclus 
iindidatus.  The  determination  of  species 
in  Actinopts'chus  is  very  difiicidt.     The 


of  two  dissimilar  plates,  one  having  the    number  of  the  compartments,  generally 
usual  character,  the  other  being  triradiate    relied  upon,  we  con.^ider  unessential,  and 


840 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


we  woiild  separate  into  two  species  all 
those  forms  in  which  the  compartments, 
irrespective  of  their  number,  are  di- 
stinctly^ cellulose  without  any  particular 
arrangement  of  their  cellules.  A.  unclu- 
latus  would  thus  include  all  those  having 
a  vague  or  indefinite  umbilicus,  and  A. 
senarius  those  in  which  the  umbilicus  is 
separated  from  the  cellulose  compart- 
ments by  a  well-defined  margin. 

A.  spiendens  (Shadbolt).  —  Compart- 
ments (12  to  20)  obscurely  cellulose, 
each  with  a  median  line,  which  termi- 
nates in  a  clavate  intramarginal  nodule 
or  tooth ;  umbilicus  hyaline,  definite.  = 
Actinophcenia  spiendens,  Sh  TM.  ii.  p.  16  j 
Actinojjti/chus  sedenarius,  E.,  Ro  TM.  ii. 

f).  74,  pL  6.  f.  2.  Common.  Guano,  Eng- 
and.  In  this  species  the  alternate  de- 
pressions of  the  compartments  are  often 
very  slight ;  and  the  compartments  being 
striated,  frequently  appear  irregular,  and 
are  coimted  wdth  difficulty.  The  species 
nevertheless  has  so  peculiar  an  aspect, 
that,  once  kno"«Ti,  it  is  easily  recognized. 
The  rays  are  most  distinct  where  they 
radiate  from  the  hyaline  umbilicus,  at 
which  part  they  sometimes  appear  thick- 
ened. In  some  specimens  the  nodules 
are  confined  to  the  alternate  compai't- 
ments. 

A.  elegans  (n.  sp.). — Disk  divided  into 
compartments  by  lines  radiating  fi'om  a 
stellate,  hyaline  umbilicus  ;  compart- 
ments punctated,  and  each  bisected  by 
a  monilifonn  row  of  granules.  =A.  octo- 
detiarius,  EM.  pi.  21.  f  21.  Oran.  Ehren- 
berg  has  figm'ed  more  than  one  form  as 
his  A.  octodenanus ;  the  compartments  in 
his  figure  of  this  species  are  9,  and  each 
is  bisected  by  a  monilifonn  ray. 

A.  tnlingidatus(Bii.). — Valves  divided 
by  6  alternately  elevated  segments.  I'he 
elevated  portions  gTadually  rise  from  the 
circumference  to  near  the  centre,  where 
they  are  rounded  oft';  each  alternate  one 
has'  a  submarginal  row  of  dots  or  trun- 
cated processes.  Sm-face  delicately  punc- 
tato-sti-iate.  -0035"  to  -0073".  "  West 
Indies.     Bri  MJ.  viii.  p.  93,  pi.  5.  f.  2. 

A.  sjnnosus  (Bri.). — Valves  with  6  seg- 
ments, alternately  slightly  elevated;  mar- 


gin occasionally  spinous;  each  segment 
Tvdth  1  or  2  processes  ;  mnbilicus  smooth, 
surface  of  the  valve  punctate.  Monterey 
,  earth  (or  deposit).  Bri  MJ.  viii.  p.  94, 
pi.  (3.  f.  15. 

A.  dives  (E.).  —  Disc  divided  into 
numerous  (about  50)  narrow  compart- 
ments by  lines  radiating  from  a  large, 
indefinite,  punctated  umbilicus,  each 
compartment  having  a  single  series  of 
granules.  EM.  pi.  19.  f.  12.  =Discoj)lea 
dives,  E. ;  Cyclotella  dives,  KA.  p.  20. 
Fossil.     JEgina. 

Doubtful  Species. 

A.  qiiaternarius  (E.).  —  Disc  divided 
into  4  compartments  by  as  many  radi- 
ating lines.  KA.  p.  130.  Virginia. 
Diam.  1-552".     A  state  of  A.  ternarius  ? 

A.  ?  hexapterus  (E.).  —  Disc  \\ath  6, 
thick,  solid  and  conical  rays ;  margin 
thick,  undulated,  denticulate  internally. 
KA.p.l31.  Fossil.  Vera  Cruz.  (xi.  31.) 
A  very  doubtfid  Diatom. 

A.  octonarins  (E.). — Disc  divided  into 
8  compartments  by  as  many  radiating 
lines.   Guano,  &c.    A  state  of  "^4.  senarius. 

A.  denarius  (E.). — Disc  with  10  com- 
partments and  10  radiating  lines.  EM. 
pi.  18.  f.  23.  Cuxhaven  and  Virginia. 
We  believe  this  species  is  foimded  on 
certain  forms  of  A.  senarius  and  A. 
spiendens. 

A.  duodenarius  (E.). — Disc  divided  by 
radiating  lines  into  12  compartments, 
which  are  alternately  darker ;  in  the 
centre  of  each  compartment  runs  a  nar- 
row line,  terminating  at  the  margin  in  a 
minute  pseudo-nodule,  so  that  as  many 
as  24  rays  may  be  counted.  Eecent  and 
Fossil.  Europe,  America.  KA.  p.  131. 
=  HeUopeUa  Phaethon,  MJ.  viii.  p.  13  ? 
A  state  of  A.  sj^lendens  ? 

The  following  species  of  Ehrenberg 
are  distinguished  by  the  nimiber  of  rays 
only : — 

A.  quatuoj'defiarius,  14  rays=^.  ^len- 
dens;  A.  vicenarius,  20  ravs;  A.  Ceres, 
22  rays ;  A.  Jupiter,  24  rays  (xi.  28). 
The  three  last  are  probably  states  of 
A.  splejulens. 


Genus  HELIOPELTA  (Ehr.).  —  Frustules  disciform,  undulated  disc  cellu- 
lose, with  external  rays  and  internal  septa,  a  striated  margin,  many  erect 
submarginal  teeth,  and  an  angular  centre.  As  in  Actinoptychus,  the  frustiile 
is  undulated,  and  the  disc  divided  into  cuneate  compartments  or  rays,  which 
appear  alternately  more  distinct ;  "  but,  in  addition,  they  have  near  the 
margin  a  row  of  lateral  spines,  somewhat  like  the  processes  of  Eupodiscus, 
but  far  more  numerous,  which  probably  connect  the  frustiJes  together  in  the 


OF  THE  COSCINODISCEiE. 


841 


young  state.  Ehrenberg  has  dedicated  the  different  species  of  this  genus  to 
persons  distinguished  in  the  history  of  microscopic  research  "  (Bailey).  As 
the  species  differ  only  in  the  number  of  compartments,  they  are  probably  not 
truly  distinct. 


Heliopelta  J/f^n  (E.). — Disc  having 
loosely  cellulose,  elevated,  radiating  com- 
partments, alternating  with  depressed 
ones  marked  with  tine  decus^sating  lines; 
border  a  rather  broad  striated  rim.  Ber- 
muda deposit,  (xi.  35.)  Compartments 
6;  umbilicus  stellate.  Diam.  1-372". 
Has  the  habit  of  Actinoptijchus  velatus. 
=  H.  Metii,  EB.  1844,  p.  268.  Com- 
partments 8 ;  umbilical  star  tetragonal. 
Diam.  1-204". 

H.  Leeiiwenhoekii  (EM.  pi.  33. 18.  f.  5.). 
— Compartments  10 ;  umbilical  star  pen- 


tagonal.   Diam.  1-156". 

H.  Eideri  (EM.  pi.  33.^  18.  f.  6.).  — 
Compartments  12 ;  umbilical  star  hex- 
agonal.    Diam.  1-156". 

H.  SeUiquerii  (EB.  1844,  p.  268.).  — 
There  are  usually  3  teeth  opposite  each 
elevated  compartment,  and  2  opposite 
each  depressed  one ;  but  sometimes,  es- 
pecially in  the  larger  specimens,  the  teeth 
are  more  numerous,  whilst  in  the  smaller 
ones  they  are  occasionally  1  less  in  each 
compartment. 


Genus  OMPHALOPELTA  (Ehr.).— Fmstules  simple,  disciform ;  disc  cellu- 
lose or  punctate,  divided  by  imperfect  septa  into  cuneate  rays  ;  centre  hyaliue ; 
spines,  one  to  each  compartment.  "  This  genus  has  the  habit  of  Actinoptychus 
and  Heliopelta,  but  differs  from  the  former  in  the  presence  of  lateral  spines, 
and  from  the  latter  in  the  small  number  of  these  processes.  The  species  of 
these  three  genera  often  closely  agree  in  their  form  as  well  as  in  the  number 
of  their  radii  and  cells  ;  but  the  character  of  the  spines  will  always  distinguish 
them"  (Bailey).  ''  All  the  species  of  Omphalopelta  resemble  Actyno^tyclms 
senarius^'  (Kg.). 

Heliopelta  differs  from  this  genus  in  having  two  or  more  spines  instead  of 
one  to  each  compartment, — a  difference  we  regard"  as  more  suitable  for  specific 
than  generic  distinction;  and  we  believe  that  a  better  knowledge  of  these 
forms  will  prove  the  propriety  of  uniting  them. 

Omphalopelta  cellulosa  (E.).  —  Ra- 
diating compartments  6,  cellulose,  al- 
ternately tumid  and  depresed,  stellato- 
punctate  ;  rays  but  slightly  prominent ; 
rim  broad,  striated.  KA.  p.  133.  Fossil. 
Bermuda,  Virginia.  Diam.  1-192".  This 
species  greatly  resembles  the  6-rayed 
form  of  Heliopelta  3Ietii,  in  which  the 
compartments   have   sometimes   only  1 


and  2  spines  alternately ;  and  indeed  we 
are  not  certain  that  they  are  even  speci- 
fically distinct. 

0.  areolata  (E.).  —  Compartments  6, 
all  loosely  and  obscurely  cellulose, 
scarcely  or  but  slightly  depressed;  rays 
distinct ;  rioi  broad,  radiate.  EM.  pi.  35  a. 


18.  f.  12.  =  Actinocydus  areolatus,  Bri  MJ. 
viii.  p.  93,  pi.  5.  f.  1.  Fossil.  Bermuda, 
guano.     {\Tii.  15.) 

0.  ve)'sicolor  (E.).  —  Compartments  6, 
all  granulated  in  very  fine  decussating 
lines,  which  cause  a  play  of  colours  from 
tawny  to  red ;  the  strong  rays  and  hex- 
agonal crystalline  umbilicus  ^ery  conspi- 
cuous ;  rim  naiTOw,  radiant.  KA.  p.  133. 
Fossil.  Bermuda.  Diam.  sometimes 
1-252",  but  mostly  less. 

0.  pu7ictata  (E.). — Radiating  compart- 
ments 6,  all  loosely  punctated,  3  alter- 
nate ones  slightly  elevated ;  rim  narrow, 
not  distinctly  radiant;  spines  obsolete. 
KA.  p.  133.     Fossil.     Bermuda. 


Genus  ARACHNOIDISCUS  (Deane).— Frustules  disciform ;  disc  with  a 
central  hyahne  nodule  or  umbilicus,  and  numerous  radiating  liaes  connected 
by  concentric  lines  or  series  of  gemmaceous  granules. =Hemiptychus  (E.). 
The  disc  has  been  compared  to  a  spider's  web  ;  hence  the  name.  Alternating 
with  the  long  radiate  Hues  are  one  to  thi^ee  short  marginal  ones,  the  central 
one  of  these  being  also  longer  than  the  other  two  when  three  are  present. 
Professor  Bailey  informs  us  that  Arachnoidiscus  has  been  adopted  instead  of 
Hemiptychus  because  the  latter  name  had  previously  been  used  in  ento- 
mology. 


842 


SYSTEMATIC  HISTORY  OP  THE  INETJSORIA. 


Arachnoidiscus  ornatus  (E.). — Disc 
having  its  radiating  lines  connected  by 
concentric  ones.  =  ITemiptychus  ornatus, 
EB.  1848,  p.  7 ;  Arachnoidiscus  ornatus, 
EB.  1849,  p.  64  ;  Ar  TM.  vi.  p.  16 ; 
A.  JaponicKS,  Shadbolt;  A,  Nicoharicus, 
EM.  pi.  36.  f.  35  (according  to  Arnott). 
Africa,  West  Coast  of  America,  Nicobar 
Islands,  (xv.  18-21.)  In  deference  to  the 
opinion  of  Prof.  Arnott,  we  liave  united 
A.  Nicoharicus  to  this  species ;  but  it  is 
desirable  to  examine  specimens  from  the 
original  stations.  Ehrenberg  describes 
all  the  radiating  lines  in  his  A.  ornatus  as 
equal ;  but  he  figures  A.  Nicoharicus  with 
two  sets  of  shorter,  marginal,  interme- 
diate ones.  Our  specimens,  in  this  re- 
spect, agTee  with  A.  Nicoharicus,  but 
have  around  the  umbilicus  a  circlet  of 
close,  short,  radiant,  oblong  lines,  which 
are  wanting  in  Ehrenberg's  figure.  The 
granules,  too,  are  apparently  larger  in 
our  specimens.  The  lines  connecting  the 
radiating  ones  often  anastomose. 

A.  Ehrenbergii  (Bailey). — Disc  with 
numerous,  moniliform,  concentric  circles 
of  large  pearly  granules,  the  circle  next 
the  umbilicus  formed  of  short  lines; 
radiating  lines  wdth  two  series  of  shorter 
ones  between.  =  ^.  Ehrenherqii,  EB.1849, 
p.  64 ;  SD.  i.  p.  26,  pi.  31.  f.  256.  Eecent, 
Coast  of  Oregon  and  California;  fossil, 
Monterey  and  California.  A.  Ekren- 
hergii  is   easily   distinguished   from  A. 


ornatus  by  the  absence  of  concentric 
lines.  It  is  more  hyaline,  and  the  gra- 
nules far  larger  and  more  conspicuous. 
All  the  circles  are  compact,  and,  except 
the  two  inner  ones,  have  the  granules 
slightlv  quadrate,  and  their  relative  di- 
stances somewhat  irregular.  The  second- 
ary rays  are  sometimes  half  the  length 
of  the  principal  ones ;  the  third  series  is 
simplv  marginal. 

A.  hidicus,  EM.  pi.  36.  f.  34.  India. 
We  have  seen  neither  specimen  nor  de- 
scription of  this  species.  Ehrenberg's 
figm-e  represents  the  disc  with  numerous, 
concentric,  moniliform  circles  of  pearly 
granules.  The  granules  are  distant  in 
the  first  and  third  from  the  umbilical 
space ;  in  all  the  others  they  are  dense. 
Professor  Arnott  (perhaps  rightly)  imites 
A.  Indicus  to  A.  JSJirenhergii ;  but  we 
have  thought  proper  to  keep  them  sepa- 
rate for  the  present,  in  order  to  direct 
more  attention  to  them,  because  Ehren- 
berg's figm*e  of  A.  Indicus  differs  in  some 
respects  from  A.  Ehrenhergii.  In  this 
species  there  is  no  linear  series  roimd 
the  umbilicus,  the  third  circle  has  distant 
granules,  all  the  granules  are  orbicular, 
there  is  only  one  series  of  shorter  rays 
interposed  between  the  long  ones,  and 
these  are  connected  by  an  imdulated 
line,  giving  the  inner  margin  of  the  rim 
a  scolloped  appearance.  In  all  these 
respects  it  difiers  from  A.  Ehrenhergii. 


Genus  PEHITHYEA  (Ehr.). — Characters  unknown  to  us.  According  to 
Ehrenberg's  figures,  it  seems  to  differ  fi^om  Heterostephania  by  its  larger 
tubercles. 


Perithyba  denaria,  EM.  pi.  35  a.  9. 
f.  5.  =  Coscinodiscus  radiatits,  var.,  Wal- 


lich,  TMS. 


pi.  2.  f.  22  ?     Ganges. 


Disc  with   radiating   series   of    minute 
puncta,  ten  intramarginal  tubercles,  a 


rather  broad,  smooth  rim,  and  no  umbi- 
licus,   (viii.  19.) 

P.  quaternaria,  EM.  pi.  35  a.  9.  f.  6. 
Ganges.  A  variety  of  the  preceding, 
with  only  foiu'  tubercles. 


FAMILY  IX.— EUPODISCE^. 

Frustiiles  simple,  free,  disciform  ;  lateral  surfaces  furnished  with  processes. 
The  Eupodiscese  may  be  regarded  as  connecting  the  Coscinodisceae  with  the 
Biddulphiese.  They  agree  with  the  former  in  theii'  discoid  fnistules  and  with 
the  latter  in  having  processes  on  the  lateral  surfaces.  These  processes,  how- 
ever, must  not  be  confounded  with  the  spines  or  teeth  which  occiu'  in  some 
of  the  Coscinodisceae.  It  is  sometimes  difiicult  to  decide  whether  the  discs 
really  have  processes  or  only  pseudo-nodules,  since,  from  their  circular  out- 
line and  hyaline  texture,  free  from  cellules,  both  these  appear  like  orifices 
unless  seen  in  profile,  and  perhaps  Aetinocyclus  would  be  more  correctly 
placed  in  this  family  than  with  the  Coscinodisceae. 

Genus  EUPODISCUS  (Ehr.).— Frustides  disciform ;  disc  cellulose  or  gra- 
nulate, furnished  with  submarginal  circular  prominences.  =  Tripodiscus,  Tetra- 


OF  THE  EUrODISCEiE. 


843 


podisciis,  Pentapodisciis  (E.),  Podisciis  (Bail.).  The  cellular  structure  is 
usually  less  evident  in  this  genus  than  in  Coscinodiscus.  'W^'e  have  removed 
to  Actinocyclus  thi^e  species  originally  placed  here  by  Professor  Smith,  who 
himself  admits  that  they  probably  belong  to  that  genus,  "  as  the  process  in  all 
is  rather  a  pseudo -nodule  than  a  projection  from  the  surface  of  the  valve." 

EuPODiscus  Argus  (E.).  —  Disc  with 
three  or  more  processes,  subremote  from 
the  margin ;  cellules  somewhat  stellate, 
intervals  punctated.  SD.  i.  p.  24,  pi.  4. 
i.  39.  =  E.  Amencam(s,  EB.  1844 ;  K 
quaternarius,  E.  quinarius,  E.  Germa- 
nicus,  KA.  p.  134.  (xi.  2:  xi.  41,  42.) 
Recent  in  marine  and  brackish  water, 
Europe,  America ;  fossil.  United  States. 
This  species  is  easily  recognized  by  its 
irregular  cellules  and  intervening  puncta, 
which  give  to  the  disc  a  clouded  appear- 
ance, very  unlike  the  usual  transparency 
of  Diatomaceae.  The  processes  vary  from 
3  to  5  in  number.  "  The  star-shaped 
cells  appear  -when  seen  by  direct  light 
to  be  placed  in  the  centre  of  small  bosses 
or  protuberances,  in  which  respect  it  dif- 
fers from  all  other  Diatomacese  that  I 
am  acquainted  with.     Ro  MJ.  ii.  p.  73. 

E.  motistnwsiis  (E.). — Disc  with  4  pro- 
cesses on  one  side.  E.  /.  c.  p.  81.  Baltic. 
Distinguished  by  the  unsymmetrical  dis- 
position of  its  processes.  It  is  probably 
an  accidental  variety  of  E.  Argus. 


E.  Roger sii  (Bail.,  E.).  —  "Frustules 
large,  having  3  to  7  hyaline  lateral  pro- 
cesses placed  on  an  elevated  circle, 
within  which  the  disc  is  slightly  con- 
cave, and  outside  of  which  the  surface 
is  part  of  the  frustum  of  a  cone.  =  Po- 
discus  Rogersii,  BAJ.  xlvi.  pi.  3.  f.  1,  2 ; 
Eujjodiscus  Rogersii,  E.  /.  c. ;  E.  Bailegii, 
E.  /.  c.  Recent  and  fossil.  United 
States.  In  this  species  the  processes 
are  close  to  the  rim.  The  whole  surface 
is  beautifully  punctate.  ...  As  this  spe- 
cies is  the  largest  and  most  beautiful  of 
the  fossil  Infusoria  occurring  in  the  strata 
of  which  Professor  W.  B.  Rogers  made 
the  discovery,  I  have  selected  it  as  pe- 
culiarly appropriate  to  bear  his  name  " 
(Bail.  /.  c). 

E.  radiatus  (Bail.). — Disc  plane,  areo- 
lation  hexagonal,  with  4  (or  more)  sub- 
marginal  processes.  "  Resembles  Cosci- 
nodiscus radiatus  in  size  and  reticulation," 
BC.  Bri  MJ.  viii.  p.  95,  pi.  5.  f.  10. 
America. 


Genus  AULACODISCUS  (Ehi\). — Frustules  disciform ;  disc  granulated,  and 
furnished  with  intramarginal,  shortly  tubular  processes,  each  connected  with 
the  centre  by  a  distinct  furrow,  or  by  a  radiant  series  of  more  conspicuous 
granules.  Aulacodisci  are  Eupodisci  furnished  vdih.  bands  radiating  from  the 
centre  and  connected  with  the  tubercles  situated  just  within  the  margin,  and 
having  the  surface  of  their  valves  granulate,  and  not  cellular.  Professor 
Kiitzing  makes  this  genus  a  section  of  Eupodiscus. 

rows  aud  about  the  umbilicus;  margin 
finely  striated.  In  order  to  observe  the 
disc  properly,  it  is  necessary,  on  account 
of  its  imevenness,  to  vary  the  focus. 
Specimens  from  New  Zealand  have  the 
granules  and  markings  more  distinct, 
and  the  inflations  smaller,  less  definite, 
and  further  from  the  margin. 

A.  formosus  (Aiiiott,  MS. ) . — Disc  kuid, 
ha\ing  an  irregular  perforation-like  um- 
bilicus, a  large  cuneate  inflation  beneath 
each  process,  and  radiating  series  of  con- 
spicuous pearly  granules.  =  A.  Bright- 
ivellii,  Ralfs,  MS. ;  A.  Boliviensis,  Breb. 
MS.  In  upper  Peruvian  or  San  Filipe 
guano.  A.  formosus  agrees  with  A. 
Petersii  in  having  an  inflation  beneath 
each  process,  but  differs  in  most  other 
respects.  From  A.  margaritaceus  and 
A.  Comheri,  which  it  more  nearly  re- 
sembles in  the  appearance  and  arrange- 


*  Disc  huUate  heneath  the  processes. 

AuLACODiscus  Petersii  (E.).  —  Disc 
nearly  colomiess,  having  a  small,  per- 
foration-like umbilicus,  a  large  kite- 
shaped  inflation,  rough  with  minute 
points,  beneath  each  process,  and  minute 
granules  an-anged  in  lines.  EB.  1845, 
p.  361.  =  Eupodiscus  Petersii,  KS  A.  p.  135 ; 
E.  cruciger,  Sh  TM.  ii.  pi.  1.  f.  12.  South 
Africa,  both  recent  and  in  guano ;  Aus- 
tralia and  New  Zealand.  Disc  large, 
■w-ith  3  to  5  orbicular  processes,  fm-nished 
with  a  central  nipple  and  situated  on 
the  outer  margin  of  the  inflations.  The 
granules  are  minute,  and  arranged  in 
lines,  some  radiant  and  bisecting  the 
intei-vals  between  the  processes,  the  rest 
oblique  and  decussating.  Raised  points 
are  present  on  the  inflations  and  less 
conspicuously  along  the  connecting  fur- 


844 


SYSTEMATIC  HISTOKY  OF  THE  INFUSOEIA. 


ment  of  its  gi'aniiles,  it  is  easil}^  known 
by  its  inflations.  Disc  large,  smoke-  or 
lead-coloured,  with  a  narrow,  distinct, 
finely  striated  rim ;  inflations  remote 
from  the  margin,  and  having  a  bright 
point  at  the  outer  edge,  placed  at  the 
base  of  an  elongated,  clavate,  not  very 
conspicuous  process. 

2  *  Disc  not  bullate  heneath  the  processes. 

A.  scaler  (Ralfs,  n.  sp.).  —  Disc  with 
oblong  submarginal  processes,  crowded 
radiating  series  of  minute  granules,  and 
scattered  raised  points.  Peruvian  guano. 
Processes  3  to  5,  connected  by  indistinct 
grooves  with  the  very  minute  umbilicus. 
In  the  front  view  this  species  resembles 
a  Cerataulus,  its  lateral  portions  being 
turgid,  and,  in  addition  to  the  processes, 
rough  with  minute  apiculi;  connecting 
zone  marked  by  faint  longitudinal  lines. 

A.  Kittoni  (Aruott,  MS.). — Disc  hya- 
line, with  3  to  8  submarginal  crescent- 
looking  processes,  connected  by  radiant 
rows  of  minute  granules,  with  an  umbi- 
lical rosette  of  oblong  cellules.  Recent, 
New  Zealand  and  Monterey  Bay ;  fossil, 
Monterey  stone.  An  elegant  species, 
distinguished  by  its  somewhat  mammi- 
form processes,  which,  being  directed  out- 
wards, appear  lunate.  Granules  pmicti- 
form,  proceeding  from  umbilicus  to 
processes  in  pencil-like  rays ;  intei-val 
between  the  processes  bisected  by  similar 
pencils,  but  less  conspicuous,  and  with- 
out fuiTows ;  the  rest  of  the  granules  in 
oblique  lines,  as  in  A.  Petersii.  ['ypT  J^ 

A.  Jb72«somV(Ai*nott,MS.). — Disc  pale, 
with  a  circular,  perforation-like  umbili- 
cus, and  crowded  radiating  series  of  gra- 
nules becoming  more  numerous  as  they 
proceed  outwards,  so  as  to  appear  forked ; 
processes  within  the  margin,  roundish, 
small.  Algoa  Bay  guano.  The  rays, 
near  the  margin,  become  more  numerous, 
with  smaller  granules,  so  as  to  look  like 
striae;  sometimes  the  processes  appear 
within  a  faint  circle.  A.  Johnsonii  some- 
what resembles  A.  Kittoni,  but  is  less 
hyaline,  with  more  conspicuous  gra- 
nules, and  processes  more  distant  from 
the  margin. 

A.  Criix  (E.). — Disc  with  close,  radi- 
ating, forked  series  of  large  pearly  gra- 
nides,  which  are  crowded  at  the  centre, 
leaving  no  blank  space ;  processes  some- 
what distant  from  the  margin.  =  ^.  Crux, 
EB.  1844,  p.  76;  EM.  t.  18.  f.  47;  Eu- 
podisciis  Crux,  KA.  p.  135.  Fossil.  Vir- 
ginia. .  We  are  indebted  to  Professor 
Arnott  for  coiTecting  the  error  we  had 
fallen    into,  of  confounding  it  with  A. 


Kittoni.  In  general  appearance  it  agrees 
with  A.  Co7nheri  and  A.  margaritaceus ; 
but  the  processes  are  more  remote  from 
the  margin,  and  the  connecting  furrows 
obscure ;  it  difiers  essentially  from  most 
other  species  in  having  large  granules 
at  the  centre  of  its  disc,  instead  of  a 
blank  space ;  margin  striated. 

A.  tnargaritaceus  (Ralfs,  n.  sp.). — Disc 
pale,  with  oblong  submarginal  processes, 
an  iiTegular,  perforation-like  umbilicus, 
nmnerous,  close,  moniliform,  radiating 
series  of  large,  pearl}-  gTanules,  and  in- 
conspicuous connecting  fmTOws.  Patos 
or  Californian  guano.  =  A.  Crux,  EM. 
pi.  35  A.  16.  f.  2.     Disc  large,  with  from 

8  to  10  rather  small  processes ;  umbilicus 
usually  iiTcgular,  hyaline,  looking  as  if 
denuded  of  granules,  sometimes  very 
minute  and  suiTOunded  by  a  circlet  of 
larger  granules.  Two  simple  series  of 
equal  granules  lead  to  each  process,  be- 
neath which,  by  a  slight  separation,  they 
leave  a  triangular  hyaline  space ;  the 
other  series  are  dichotomously  divided, 
and  near  the  margin  their  granules  be- 
come smaller,  or  even  punctiform,  and 
resemble  stride. 

A.  Comber i{A.Ynott,  MS.). — Disc  lurid ; 
gran  ides  large,  irregularly  scattered  round 
the  iiTegidar  perforation-like  imibilicus, 
the  rest  arranged  in  crowded,  forked, 
radiating  lines;  processes  oblong,  sub- 
marginal,  with  conspicuous  connecting 
furrows.  San  Filipe  guano.  Processes 
2  to  6.  A.  Comheri  in  character  ap- 
proaches closely  to  A.  margaritaceus ;  its 
granules,  however,  are  smaller  and  more 
irreaidar  near  the  umbilicus,  and  the 
furrows  leading  from  the  processes  are 
much  more  conspicuous ;  but  the  most 
obvious  distinction  of  this  species  is  its 
lurid  appearance. 

A.  Beeverice  (Johnson,  MS.).  —  Disc 
smoke-colom-ed,  with  an  irregular  blank 
umbilicus,  rather  distant  radiating  lines 
of  large  pearly  granules,  striated  mar- 
gin, and  (3  or  4)  roundish  submarginal 
processes.  New  Zealand.  Of  this  beau- 
tiful species  we  have  seen  only  one  spe- 
cimen. The  disc  is  small,  apparently 
nearly  flat,  with  very  distinct  granules, 

9  or  iO  in  -001",  on  a  dark  ground;  two 
series  leading  to  each  process,  wider 
apart  and  more  parallel  than  the  rest. 
(VI.  5.) 

A.  Broiv7ieii  (Noi-man,  MS.).  —  Disc 
coloured,  vAth  a  minute  umbilicus,  close 
radiating  series  of  granules,  and  two  or 
three  roundish  intramarginal  processes. 
Shell-cleanings,  California  and  else- 
where in  the  Pacific.     Fossil,  Monterey 


OF  THE  ETTPODTSCEJE. 


845 


stone.  Disc  small  under  a  low  power, 
bluish,  with  a  darker,  brownish  border. 
The  granules,  which,  according  to  Mr. 
Norman,  are  about  17  in  -001",  are  so 
regularly  arranged  as  to  form  concentric 
circles  as  well  as  radiating  series.  A. 
Broivneii  agrees  in  colour  with  A.  Ore- 
ffamcs,  but  in  the  arrangement  of  its 
granules  more  resembles  A.  Beeverim. 
From  the  former  it  differs  in  the  regidar 
radiant  arrangement  of  its  granides, 
smaller  size,  fewer  processes,  and  much 
flatter  surface.  From  A.  Beeverice  it  is 
distinguished  by  its  colour  and  closer 
granules. 

A.  Or  eg  anus  (Bailev). — Disc  coloiu-ed, 
with  circidar  perforation-like  umbilicus, 
convex  centre,  flattened  border,  short 
cylindi'ical  slightly  emarginate  marginal 
processes,  and  series  of  minute  crowded 
granules.  Bail.  Proc.  Acad.  Philadelphia, 
1853 ;  Grev  MJ.  vii.  p.  156,  pi.  7.  f.  2. 
California,  both  recent  and  fossil ;  Mon- 
terey stone,  Puget's  Sound.     This  very 


distinct  species  is  easily  recognized  by 
its  colom-ed  disc  and  cylindrical  emar- 
ginate processes,  which  are  from  6  to  27 
in  number,  and  close  to  the  margin. 
Under  a  low  power  its  minute  granules 
appear  an-auged  in  waved  or  oblique 
lines,  but  imperfectly  radiant  under 
higher  powers.    (yi.  4.) 

A.. pulcher  (^OYm?in,  MS.). — Disc  large, 
colom'ed,  with  from  7  to  16  marginal 
processes ;  central  gi*anules  in-egularly 
scattered  or  crowded,  the  others  in  di- 
stinct, close,  radiant  rows.  Fossil.  Mon- 
terey stone.  A.  pulcher  agrees  with  A. 
Browneii  in  its  coloured,  slightly  and 
uniformly  convex  disc  and  radiant  ar- 
rangement of  granules.  It  differs  from 
that  species  by  its  much  larger  size  and 
more  numerous  processes.  The  most 
remarkable  feature  of  this  species  is  its 
I  granulose  centre,  in  which  respect,  as 
'  well  as  in  its  radiant  granules,  it  differs 
fi-om  A.  Oreganus.  Granides  12  in  -001". 
(\^ii.  28.) 


Genus  ArLISCUS  (Ehr.,  Bail.).—"  Fnistiiles  cylindrical  or  discoid ;  lateral 
surfaces  undulated,  having  two  circular,  flattened,  mastoid,  imperforate  pro- 
cesses at  some  distance  from  the  margin ;  umbilicus  (generally  present) 
smooth,  circular,  surrounded  by  a  plumose  arrangement  of  dots  and  lines ; 
sides  smooth"   (BC.  1854.). 

"  The  projections  on  one  valve  are  usually  on  a  line  at  right  angles  to  that 
on  which  those  of  the  opposite  valve  are  placed  "  (B.).  Xiitzing  unites  Auliscus 
'with  Coscinodiscus ;  but  it  seems  more  nearly  allied  to  Eupodiscus. 


*  Disc  with  a  conspicuous  circular 
umhilicus. 

Ariuiscvs  pruinosus  (B.). — "  Disc  with 
four  sets  of  curved  and  sparsely  pimc- 
tate  lines,  two  diverging  from  the  large 
smooth  umbilicus,  while  the  other  two 
converge  round  the  large  processes." 
BC.  1854,  pi.  1.  f.  5-8.  Ptecent.  United 
States.  (VI.  1.)  "  Frustules  large,  discoid 
or  cylindrical ;  edges  bevelled,  central 
portion  in  front  view  smooth  or  vrith 
longitudinal  parallel  lines  "  (B.).  We 
have  seen  frustides  of  this  species  with 
3  processes. 

A.  punctatus  (B.).  —  Frustules  like 
those  of  A.  pruinosus,  but  their  lines  so 
crowded  and  closely  punctate  that  the 
plumose  aiTangement  is  scarcely  visible. 
BC.  pi.  1.  f.  9.  United  States.  "  This 
may  prove  a  variety  of  the  preceding; 
but  the  sparsely  punctate  surface  of  the 
one  and  the  closely  punctate  sm-face  of 
the  other  appear  to  offer  a  sufiicient 
distinction  between  them"  (B.). 

A.  ccelatus  (B.). — Disc  with  unequal. 


the  margin  towards  the  centre,  but 
lea\dng  a  well-defined  central,  four- 
lobed  or  cruciform  figure,  with  waved 
lines  radiating  in  four  sets  from  the 
umbilicus.  BC.  pi.  1.  f.  3,  4.  In  sand 
from  West  Indian  sponge,  and  in  sound- 
ings fi'om  Mobile  Bay.  Umbilicus  di- 
stinct, smooth,  the  lines  proceeding  from 
it  towards  the  processes  in  converging 
cm-ves,  the  others  variously  flexed  and 
anastomosing. 

2  *   Umhilicus  wanting  or  obsolete. 

A.  scfilptus  (Smith).  —  Disc  with  im- 
equal,  sti'ongly  marked  short  lines,  radi- 
ating inwards  from  the  margin  and 
leaving  a  weU-defined  ceuti-al,  four- 
lobed  space,  marked  with  fom-  sets  of 
fainter  lines  radiating  from  the  centre. 
=■  Eupodiscus  sculptus,  SBD.  i.  pi.  4.  f.  42  ; 
Bri  M.I.  ^dii.  p.  94,  pi.  5.  f.  3.  England, 
(vi.  3.)  This  species  resembles  A.  cce- 
latus, but  has  no  umbilicus.  We  have  not 
seen  the  striae  of  the  central  quatrefoil  so 
strongly  marked  as  in  Professor  Smith's 


strongly  marked  lines  proceeding  from  i  figure,  but  always  much  fainter  than  the 


846 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


marginal  ones;  indeed  sometimes  tliey 
are  very  indistinct. 

A.  Americanus  (E.).  —  Disc  with 
strongly  marked  lines,  radiating  inwards 
from  the  margin  and  leaving  an  irregidar 
central  space  destitute  of  lines.  EM. 
pi.  33.  14.  f.  2.  United  States.  The 
large  processes,  as  well  as  the  central 
space,  are  without  the  radiating  lines  of 
A.  scidptus ;  but  we  think  it  probable 
that  Ehrenberg's  figm'e  was  taken  from 
a  specimen  of  that  species  in  which 
those  markings  were  more  than  usually 
inconspicuous. 

A.  cylindricus  (E.). — Frustules  cylin- 
drical, with  a  plane  orbicular  disc  on 
each  side,  having  a  rim  and  a  central 
area  marked  by  various  radiating  lines ; 
processes  resembling  oblique  openings. 

A.  oralis  (Arnott,  MS.). — Disc  oval, 
with  two  opposite,  narrow,  hispid  ele- 
vations midway  between  the  roundish 
perforation-like  apices  of  the  processes ; 
curved  lines  punctate,  rather  faint ;  um- 
bilicus obsolete.     Algoa  Bay  and  Peru- 


vian gnanos.  Communicated  by  Mr. 
Kittoni  This  species  is  distinguished 
by  its  oval  disc  and  hispid  elevations. 
The  truncated  processes  do  not  in  general 
correspond  exactly  with  the  longer  dia- 
meter of  the  valve,  but  are  placed  a  little 
on  one  side  in  opposite  directions,  in 
which  respect,  as  well  as  in  the  presence 
of  hair-like  spines,  it  approaches  Cera- 
taulus. 

Doubtful  Species. 

A.  polystigmus  (E.). — Radiating  series 
of  cellules  converging  in  two  lateral 
obsolete  whorls,  which  appear  perforated 
(processes  ?).  CelMes  14  in  1-1200". 
Diam.  1-360".=  Coscinodiscus  poly  stigma. 
KA.  p.l24.     North  Sea. 

A.  ?  gigas  (E.). — Margin  of  sides  tu- 
mid, looking  as  if  perforated,  sculptured 
bv  elegant  rows  of  dotted,  imperfectly 
radiairt  lines.  EM.  pi.  19.  f.  63.  =  Cos- 
cinodiscus  Auliscus,  KA.  p.  126.  Fossil, 
^gina.  Ehrenberg's  figm'e  represents 
a  mere  fragment. 


FAMILY  X.— BIDDULPHIEJS. 

Frustules  cellulose,  compressed ;  lateral  valves  entering  into  the  front  view, 
and  usually  more  or  less  produced,  at  one  or  both  angles,  into  processes.  The 
Biddulphieae  are  remarkable  for  the  great  development  of  the  lateral  valves  of 
the  frustule,  which  are  so  convex  or  inflated  as  always  to  enter  largely  into 
the  front  view,  causing  the  central  zone  to  appear  like  a* band  between  them. 
The  mode  of  growth  in  this  family  is  very  interesting.  Instead  of  simple 
elongation  and  subsequent  division  of  the  central  zone  by  means  of  internal 
septa,  new  central  and  inner  lateral  valves  are  formed  within  the  elongated 
original  one,  which,  until  ruptured,  retains  the  frustules  in  pairs.  The  central 
zone  is  at  first  very  narrow  and  merely  a  broad  line,  but  it  increases  greatly 
in  breadth  until  the  new  frustules  are  fully  formed. 

Genus  CERATAULUS  (Ehr.). — Frustules  with  turgid  lateral  valves,  each 
valve  with  two  tubular  processes  alternating  with  the  same  number  of  horn- 
like spines  ;  lateral  view  orbicular  or  broadly  oval.  Cerataulus  seems,  in  some 
measure,  to  connect  the  Biddulphieae  with  the  Eupodiscege,  since,  in  a  lateral 
view,  it  approaches  the  latter  in  the  cii'cular  form  of  some  of  its  species ;  the 
front  view,  however,  is  similar  to  the  other  genera  of  this  family :  the  frus- 
tules are  binately  conjoined  by  an  external  punctated  sheath,  and  their  pro- 
cesses are  definite  in  number.  Ehrenberg  describes  the  frustules  as  simple, 
by  complete  fission  ;  but  Professor  Bailey  finds  them  concatenate.  Cerataulus 
is  characterized  by  having  stout  horn-like  spines,  which  are  not  situated  on 
protuberances  between  the  two  processes,  but  alternate  with  them,  and  form 
part  of  the  same  circle. 


Ceuataulus  turgidus  (E.).  —  Pro- 
cesses short,  broad,  and  truncate  ;  lateral 
valves  broadlv  elliptic,  with  a  submar- 
ginal  band  of  apiculi.  EB.  1843,  p.  270. 
Biddnlphia  turgida,  SBD.  ii.  p.  50,  pi.  62. 


f.  384;  Ro  TMS.  vii.  p.  17,  pi.  2.  f.  23. 

Europe,  America.  Professor  Bailey  thus 
describes  this  species : — "  Frustules  glo- 
bular or  slightly  compressed,  with  two 
large  prominences  at  each  end,  cohering 


OF  THE  BIDDULPHIE^. 


847 


by  alternate  angles,  forming  zigzag 
chains.  Between  the  two  processes,  and 
in  a  plane  at  right  angles  to  that  con- 
taining them,  are  placed  two  long  horn- 
like processes.  Two  frustules  are  often 
connected  by  an  external  decussately 
punctate  cell,  as  in  Isthmia  and  Bid- 
dulphia."  The  processes  do  not  exactly 
correspond  with  the  angles,  but  are  situ- 
ated a  little  to  the  side  in  opposite  di- 
rections. This  species,  beautifully  figured 
in  Professor  Smith's  excellent  work,  is 
easily  recognized  by  its  broad,  truncated 
processes,    (vi.  8.) 

C.  Smithii  ( Ra.). — Valves  in  front  view 
turgid ;  processes  conic,  alternating  with 
subidate  hom-like  spines ;  lateral  valves 
orbicular ;  cellules  distinct.  =  Eupoclisciis 
racliatus  ?,  SBD.  i.  p.  24,  pi.  30.  f.  255 
(not  Bailey) ;  Biddulpliia  radiata,  Ro 
TMS.  vii.  p.  19,  pi.  2.  f.  27-29.  Thames. 
The  orbicular  form  and  diiferently  shaped 
processes  distinguish  this  species  from 
the  preceding.  The  cellules  are  not 
radiant ;  and  as  Professor  Smith's  name 
was  bestowed  in  error,  and  is  liable  to 
mislead,  we  have  thought  it  advisable  to 
change  it. 

C.  Icevis  (E.). — Frustules  large,  qua- 
drangular, with  short,  broad,  truncate 
processes  and  straight  intermediate  mar- 
gin ;  valves  suborbicular,  obscm*ely  punc- 
tate, with  two  minute,  opposite,  subme- 
dian  spines.  =  Biddulphia  Icevis,  EB.  184.3, 
p.  122  5  Ro  MJ.  ^-ii.  p.  18,  pi.  2.  f.  24-26 ; 


Odontella  polymorpha,  KB.  1844,  pi.  29. 
f  90;  Isthmia  polymorpha,  Montague. 
Shores  of  North  and  South  America. 
(YI.  7.) 

C.  theri7ialis  (Me.). — Large,  joints  cy- 
lindrical, angularly  concatenated  by  a 
lateral  isthmion  ;  lateral  valves  A^ery 
smooth.  =  Melosira  (Pienrosira)  thermalis, 
Menegh.  'On  the  Animal  Nature  of 
Diat.,'  p.  391.  Warm  springs  of  Eugania. 
Length  of  frustules  very  variable.  Kiitz- 
ing  refers  this  to  the  preceding  species, 
— a  decision  from  which  Meneghini  dis- 
sents. The  following  extracts  are  taken 
from  the  work  of  the  latter : — "  Kiitzing 
says,  '  Your  Melosira  (Fleurosira)  ther- 
malis is  in  no  respects  different  from  the 
Odontella  polymor2)ha.  I  have  compared 
your  specimen  with  that  of  Montague. 
There  are  even  found  the  delicate  points 
upon  the  shield,  as  in  the  other,  which  I 
have  inadvertently  omitted  in  my  figure. 
Your  specimen  is  certainly  an  Odontella, 
although  the  articulations  are  cylindri- 
cal.' "  On  this  opinion  Meneghini  makes 
the  following  comments:  —  "Although 
I  have  had  an  opportunity  of  examining 
fi-agments  only  of  Montague's  Isthmia 
polymorpha,  I  am  positive  in  treating 
the  matter  differently.  It  is  admirably 
figured  by  Kiitzing ;  the  articulations  are 
not  cylindrical,  and,  though  obtuse  and 
slightly  prominent,  the  lateral  processes 
are  very  evident."  For  other  distinctions 
between  them,  see  the  work  quoted,  p.  483. 


Genus  BIDDULPHIA  (Gray).  —  Fnistules  compressed,  quadrilateral, 
cohering  by  their  alternate  angles,  and  thus  forming  a  zigzag  chain ;  angles 
equal,  elongated  into  tooth-like  projections  ;  spines  none,  or  confined  to  the 
intermediate  rounded  projections ;  lateral  valves  constricted  laterally  at  their 
base.  Great  difference  of  opinion  exists  as  to  the  proper  arrangement  of  the 
forms  here  associated,  whether  they  should  be  included  in  a  single  genus  or 
not.  Ehrenberg  and  Kiitzing  distribute  them  in  two  genera ;  but  although 
their  genera  appear  identical,  yet  their  definitions  differ  so  much  as  to  make 
the  agreement  in  fact  merely  nominal.  Professor  Smith  unites  Cerataulus  and 
Zygoceros,  as  well  as  Odontella,  to  Biddulphia,  whilst  Professor  Bailey,  whose 
opportunities  of  studpng  this  family  have  been  so  ample,  admits  the  propriety 
of  conjoining  Biddulphia  and  Odontella,  but  is  not  prepared  to  add  Zygoceros. 
Brebisson,  who  first  conjoined  Biddulphia  and  Odontella,  subsequently  recog- 
nized both  genera.  Ehrenberg  and  Kiitzing  concur  in  describing  Biddulphia 
and  Odontella  (DenticeUa,  E.)  as  concatenate,  and  Zygoceros  and  Hemiaulus 
as  simple.  Ehrenberg  distinguishes  Biddulphia  from  Odontella  by  the  ab- 
sence of  spines,  which  are  present  in  the  latter.  Kiitzing,  on  the  other  hand, 
characterizes  Odontella  as  smooth  (not  cellulose,  though  often  pimctate  or 
granulate),  without  internal  septa,  and  Biddulphia  as  regularly  punctato- 
cellulose,  with  internal  septa.  Smith  finds  spines  in  the  typical  species  of 
Biddulphia ;  and  Baile}^  considers  the  presence  or  absence  of  spines  an  unim- 
portant accident.    We  retain  our  former  opinion,  that  we  cannot  exclude  any 


848 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


species  from  Biddulphia  merely  on  account  of  the  absence  of  costae,  without 
violating  natural  affinity,  and  dividing  Isthmia  also.  In  Biddulphia,  Klitzing 
forms  his  species  solely  from  the  number  of  lateral  costse  and  consequent 
divisions  (chambers)  ;  his  species,  however,  have  been  generally  rejected ;  and 
we  think  that,  like  similar  characters  in  Actinoptychus  and  other  genera,  such 
distinctions  are  essentially  erroneous. 


*  Valves  with  undulating  margins  and 
tratisverse  cost(S  or  depressions, 

Biddulphia  pidchella  (Gray). — Fms- 
tiiles  distinctly  reticulated  ;  valves  with 
obtuse  processes,  and  from  one  to  five 
smaller  intermediate  projections  sepa- 
rated by  costee  extending  to  the  sutm^e. 
SD.  ii.  p.  48,  f  321.  B.  trilocidaris,  Kutz. 
(with  two  costae) ;  B.  quinquelocidaris, 
Kiitz.  (with  four  costae)  ;  B.  sejjtemlocu- 
laris,  Kiitz.  (with  five  costae)  ;  Denticella 
Biddulphia,  E.  (central  projection  armed 
with  spines)  ;  B.  australis,  Montague ; 
B.  elongata,  Montague  ("udth  broad  cen- 
tral portion),  (ii.  46  to  50.)  The  di- 
stinctive character  of  this  species  is  the 
costae  or  imperfect  septa  which  separate 
the  projections.  Lateral  valves  oval,  with 
undulated  margins  and  a  large  pseudo- 
opening  at  each  end.  In  the  young  state 
there  is  only  one  rib,  and  no  interme- 
diate projection. 

B.  Regina  (Sm.). — Valves  with  three 
median  elevations,  the  central  one 
largest,  imarmed ;  processes  little  ex- 
ceeding the  median  elevation  in  length, 
papillate,  rounded  ;  cellules  of  elevation 
distinct,  those  of  valves  and  central  zone 
minute.  SD.  ii.  p.  50,  pi.  46.  f  323  ; 
Ro  TMS.  vii.  p.  8.  Dredged  ofi"  the 
Island  of  Skye.  Professor  Bailey  refers 
this  species  to  B.  tridentata,  and  Pro- 
fessor AVilliamson,  according  to  Pro- 
fessor Smith,  to  B.  Tuomeyi.  We  have 
seen  no  specimen,  but  trust  to  the  well- 
knoT\Ti  accuracy  of  Professor  Smith's 
figures  for  its  distinctness  in  the  form 
and  comparative  shortness  of  its  pro- 
cesses. 

B.  tridentata  (E.).  —  Lateral  valves 
dotted,  having  elongated,  obtuse  pro- 
cesses, and  one  to  three  imequal  inter- 
mediate projections ;  constrictions  ap- 
proaching the  suture.  EM.  pi.  19.  f  21. 
=  Denticella  tridentata,  E.  (central  pro- 
tuberance armed)  ;  Denticella  Tridens,  E. 
Fossil.  America.  Professor  Bailey  re- 
fers B.  Regina,  Sm.,  to  this  species,  but, 
judging  from  the  descriptions  and  figures, 
they  seem  to  us  distinct.  In  this  species 
the  processes  are  more  slender,  longer 
than  the  intermediate  projections,  and 
mostly  constricted    beneath    the   apex. 


Mr.  Roper  unites  this  species  to  B. 
Tuomeyi,  and  is  probably  right  in  so 
doing. 

B.  obtusa(K.). — Frustulesvery  smooth, 
short,  with  turgid,  obtuse,  short  horns, 
and  a  very  short  intermediate  process.  = 
OdojiteUa  ohtusa,  KA.  p.  136.  Heligo- 
land,    (xm.  30  to  32  a.) 

B.  suhcequa  (K.). — Frustules  oblong, 
very  smooth;  horns  minute,  without  inter- 
mediate projections.  =  Odontella  suhcequa, 
KB.  pi.  18.  8.  f  4,  5.  Heligoland.  Pro- 
fessor Smith  is  probably  right  in  regard- 
ing the  last  two  as  states  of  B.  aurita. 

B.  Iceris  (E.).— Has  the  habit  of  B. 
aurita,  but  its  valves  are  smooth  and 
tridenta,te.  =  Denticella  Icevis,  EM.  pi.  33. 
15.  f  6.  Antarctic  Sea.  Diam.  432". 
Ehrenberg's  figm-e  of  this  species  but 
slightly  resembles  B.  aurita:  the  horn- 
like processes  are  elongated,  slender,  and 
awl-shaped,  and  not  the  least  inflated  at 
the  base ;  the  intermediate  margin  also 
is  convex,  and  not  elevated  into  a  central 
projection. 

B.  Tuomeyi  (B.). — Valves  having  ob- 
tuse horns  w4th  swollen  bases,  between 
which  are  from  one  to  three  shorter, 
roimded  projections,  the  middle  one 
largest,  and  often  bearing  two  spines.  = 
Zygoceros  Tuomeiji,  BAJ.  xhd.  pi.  3. 
f  3  to  9.  Fossil.  America,  Patos  guano, 
(vi.  10.)  The  central  zone  is  narrow- 
linear,  and  slightly  projects  at  each  end  ; 
lateral  valve^covered  with  shagreen-like 
asperities,  which  are  most  evident  on  the 
projections;  processes  generally  con- 
stricted. At  the  base  of  each  swelling 
is  a  short,  linear,  hyaline  line  which  re- 
sembles a  perforation,  but  which  we  be- 
lieve is  really  a  smooth  elevation. 

B.  polymer  a  (E.).  —  Lateral  valves 
granidated,  verj-  broad  and  short ;  angles 
elongated  into  conical  processes ;  inter- 
mediate projections  several  (about  nine), 
rounded,  the  central  one  largest.  =  Denti- 
cella? polymera,  E.,  BAJ.  xhdii.  pi.  4. 
f  20 ;  bdontella  ?  polymera,  K.  ;  B. 
Tuomeyi,  Ro  TMS.  vii.  p.  8.  Fossil. 
Bermuda.  The  lateral  valves  are  so 
short  that  the  constrictions  between  the 
lobes  reach  nearly  to  the  base.  This 
species  is  remarkable  for  the  great  num- 
ber of  intermediate  projections,  of  which 


OF  THE  J3IDDULPJffIE.I 


849 


the  central  one  is  the  largest,  the  others 
decreasing  regularly  on  each  side,  two  of 
them  aimed.  Mr.  Roper  unites  this  form, 
probably  correctly,  with  B.  Tuomeyi. 

2  *  Valves  lanceolate  or  elliptical,  ivithout 
undulated  margins  (Odontella,  Ag.\ 

B.  aurita  (Lyngb.,  Breb.). — Frustides 
finely  pimctated ;  angles  prolonged  into 
slender  conical  horns,  with  an  interme- 
diate projection,  which  is  iLSually  fur- 
nished with  a  few  spines ;  valves  elliptic- 
lanceolate.  SBD.  ii.  p.  49,  pi.  45.  f.  319. 
=  Odontella  aurita,  Ag.,  K. ;  Denticella 
aurita,  E. ;  Denticella  gracilis,  E.  Ame- 
rica, Africa,  Europe. 

B.  Roperiana  (Grev.). — Valve  elliptical 
oval,  with  central  elevation,  which  in 
front  view  is  depressed  or  sometimes 
bilobed,  punctate,  unarmed  j  angular  pro- 
cesses scarcely  produced,  obtuse,  largely 
inflated  at  base ;  connecting  zone  with 
rows  of  minute  granules,  parallel  with 
suture  of  the  valve.  Grev  JMS.  vii. 
p.  163,  pi.  8.  f.  11-13.  Seaweed,  Mon- 
terey ;  Californian  guano.  ^'  This  species 
appears  to  be  removed  from  B.  aurita  and 
its  varieties  by  the  absence  of  spines,  and 
the  very  depressed,  often  two-lobed  cen- 
tral elevation  of  the  valve  "  (Grev.). 

B.  longicruris  (Grev.). — Valve  in  front 
view  with  central  elevation,  bearing  a 
very  long  spine  ;  angular  processes  very 
much  produced,  awl-shaped  ,•  surface 
minutely    granulate.      Grev   JMS.    vii. 

g.  163,  pi.  8.  f.  10.  Californian  guano ; 
ieiTa  Leone. 

B,  turgida  (E.). — Lateral  portions  in 
front  view  scabrous,  with  produced, 
conical,  obtuse  angles,  and  two  distant, 
long,  intermediate  spines;  valves  elliptic- 
lanceolate.  =  Denticella  turqida,  EB. 
1840,  p.  207,;  Odontella  turgida,  KB. 
t.  18.  f.  89  J  Biddulphia  qranulata,  Ro 
TMS.^  ^di.  p.  13,  pi.  1.  f.  10,'ll.^  Atlantic. 
Britain.  Processes  large,  inflated  at 
base,  slightly  recui-ved ;  spines  generally 
slightly  bent  at  the  middle  j  valves  rough 
with  minute  apiculi. 

B.  reticulata  (Ro.). — Valves  hirsute, 
with  large  hexagonal  reticulations ; 
processes  obtuse,  -subconic,  inflated  and 
gibbous  at  the  base.  Ro  TMS.  vii.  p.  14, 
pi.  2.  f.  14-17.  Ceylon,  Natal,  New 
Zealand.  Valves  elliptic;  connecting 
zone  having  rows  of  rather  conspicuous 
dots. 

B.  Indica  (E.,  Ro.). — Valves  hirsute, 
with  slender,  elongated,  subcapitate  pro- 
cesses, and  a  long  awl-shaped  spine 
near  each  process.     Ro  TMS.  vii.  p.  16, 


pi.  2.  f.  20-22.  =  Denticella  Indica,  ERBA. 
1845,  p.  302.  _  Natal,  (vi.  12.)  Valves 
lanceolate,  with  the  pseudo-apertures  at 
right  angles  to  the  length  of  the  valve, 
Roper. 

B.  tumida  (E.,  Ro.). — Valves  broadly 
elliptic,  with  very  fine  radiating  dots, 
and  two  or  three  submargiual  spines  ; 
in  front  view  globose,  ^vith  tapering 
obtuse  processes.  Ro  TMS.  vii.  p.  15, 
pi.  2.  f.  18,  19.  =  Denticella  tumida, 
ERBA.  1844,  p.  "im ;  Odontella  tumida, 
KSA.  p.  137.  Bermuda  ;  Californian 
guano. 

B.  Macdonaldii  (Norman,  MS.).  — 
Fnistules  finely  striated,  with  very  short, 
nearly  obsolete  processes;  valves  with 
transverse  strife  interrupted  by  a  median 
line.  Shark's  Bay,  Australia,  (vni.  23.) 
Valves  minutely  dotted  between  the 
striae  ;  frustules  somewhat  twisted.  For 
the  description  of  this  species  we  are 
indebted  to  G.  Norman,  Esq. 

Doubtful  or  imperfectly  known  Species. 

B.  ?  hrevis  (E.). — Small,  laterally  lan- 
ceolato-rhomboid,  smooth,  tripartite 
with  two  septa;  lateral  portions  also 
three-lobed ;  lobes  small,  subequal  -, 
pseudo-openings  obsolete.  KA.  p.  138. 
Portugal. 

B.  ?  gigas  (E.). — Large,  very  turgid 
at  the  centre,  rough,  without  distinct 
granules,  laterally  five-jointed,  having  a 
large,  oblong  (pseudo-)  opening  at  each 
attenuated  apex.  KSA.  p.  138.  Fossil. 
Bermuda.     l)iam.  1-144". 

B.  ?  lunata  (E,). — Valve  three-lobed, 
smooth,  slightly  cm^ved,  limate,  with 
subacute  horns.  EM.  pi.  18.  f.  53.  Fossil. 
Virginia.     Uiam.  1-864". 

B.  ?  ursina  (E.). — Large,  turgid,  not 
cellidose ;  sides  hirsute,  not  constricted, 
middle  part  smooth.  KSA.  p.  138, 
fragment.  Antarctic  regions.  Diam. 
1-192".     Remarkable  for  its  hairiness. 

B.  ?  ampliicephala  (E.). — Smooth,  nar- 
row, wand-like,  concatenate,  constricted 
beneath  each  apex ;  hence  each  end  capi- 
tate, rounded.  =  Odontella?  amphicephala, 
E.  KSA.  p.  137.  Mouth  of  the  Tagus. 
Individual  frustules  resemble  those  of 
Navicula  dicepliala  in  habit. 

B.  ?  Fragilaria  =  Denticella  ?  EM. 
pi.  21.  f.  31.  Algiers.  Perhaps  a  frag- 
ment of  Eucyrtidium  lineatuni. 

B.  ?  Cirr]ius{E.). — In  Barbadoes earth. 
We  have  seen  neither  description  nor 
figure  of  this  species. 

3i 


850 


SYSTEMATIC  HISTOKY  OF  THE  USTFUSOHIA. 


Genus  PORPEIA  (Bailey,  MS.). — Frustules  simple  (?),  compressed,  each 
valve  with  two  short  obtuse  processes,  and  two  internal  curved  plates  which 
do  not  extend  to  the  central  portion.  We  give  this  genus  in  deference  to  the 
opinion  of  oui'  higlily  esteemed  correspondent  the  late  Professor  Bailey,  but 
doubt  whether  it  is  sufficiently  distinct  from  Biddulphia.  In  Porpeia  the 
septa  appear  like  costse  incurved  at  their  inner  ends. 


Poupeia  quadriceps  (Bai.  MS.). — Pro- 
cesses with  punctated  rounded  ends,  the 
intermediate  margins  slightly  convex; 
Literal  view  narrow,  with  two  constric- 
tions, and  rounded  ends.  Gulf- stream, 
(vi.  6.)     From   drawings  by  Professor 


Bailey.  "At  first  sight  this  species 
suggests  a  relation  to  Grammatophora ; 
but  the  curved  plates  rim  at  right  angles 
to  their  position  in  that  genus  (^.  e.  not 
parallel  to  the  division  of  the  fi-ustules, 
but  perpendicular  to  it)." — B.  m  lit. 


Genus  ZYGOCEROS  (Ehr.). — Frustules  free,  compressed,  not  concatenated ; 
each  valve  with  two  (apparently)  perforated  horn-like  processes.  Although 
we  have  retained  this  genus,  yet  we  think  it  is  very  probable  that  a  better 
knowledge  of  its  species  will  justify  Professor  Smith  in  uniting  it  with 
Biddulphia,  from  which  it  differs  only  in  its  simple  frustules. 


Zygocehos  Rhomhus  (E.). — Frustules 
turgid,  with  a  smooth  or  faintly  punc- 
tated central  portion;  lateral  valve  rhom- 
boid with  rounded  angles,  its  sm'face 
having  very  fine  granulated  striae.  = 
Biddulphia  Rhomhus,  SBD.  ii.  p.  49, 
pL  45.  f.  320;  Ro  TMS.  vii.  p.  11,  pi.  1. 
£4.  America,  Europe, England.  ^, valves 
with  one  or  more  median  spines,  =  i)e«- 
ticella  Rhomhus,  E.  ;  Odontella  Rhomhus, 
K.  Large ;  strias  24  to  26  in  1-1150". 
Diam.  i-720".  "Spines  submarginal, 
awl-shaped,  abbreviated  "  (Sm.). 

Z.  radiatus  (B.).  —  Frustules  large, 
turgid;  lateral  valve  rhomboid,  with 
rounded  angles  and  radiating  series  of 
o-ranides.  BSC.  vii.  Z.  Balcena,  EM. 
pi.  35.  A.  23.  f.  17  ;  Bri  JMS.  vii.  p.  181, 
pi.  9.  f.  15.  Nova  Scotia.  "Akin  in 
liabit  to  Z.  Surirella,  but  larger  than 
Z.  Rhomhus.  Central  zone  pimctated  " 
(Ehr.). 

Z.  Surirella  (E.). — Frustules  small; 
lateral  valve  lanceolate,  with  constricted 
obtuse  apices ;  surface  with  transverse 
granular  lines,  interrupted  by  a  median 
longitudinal  band.  Ro  TMS.  ii.  pi.  6. 
f.  11,  12.  Alive.  Europe.  Thames, 
(xi.  50,  51.)  Diam.  1-720".  Central  por- 
tion smooth,  granides  of  valves  more  di- 
stinct than  in  Z.  Rhomhus.  Distin- 
guished by  the  smooth  longitudinal  line 
in  a  lateral  view. 

Z.  Bipons  (E.). — Frustules  laterally 
lanceolate,  with  acute  ends,  and  two 
smooth  medi.in  constrictions ;  granules 
delicate,  not  radiant.  KSA.  p.  139. 
Bermuda  deposit.  Diam,  1-384".  Angles 
with  small  horns.  May  be  kno-s^m  by 
haA  ing,  in  the  lateral  view,  two  trans- 
^  erse  lines. 


Z.  stiliger  (E.). — Frustules  laxly  cellu- 
lose ;  valves  with  double  median  con- 
striction of  the  side;  angles  produced 
into  long,  acute,  stiliform  horns.  KSA. 
p.  139.  Fossil.  Bermuda  deposit.  Diam. 
1-1152".  "Z.  stiliger  may  be  a  species  of 
Hemiaulus  ;  but  the  constrictions  resem- 
ble those  of  Biddulphia,  save  that  they 
want  the  wide  apertures  of  the  horns  " 
(Ehr.). 

Z.  aust rails  (E.). — Frustules  smooth ; 
horns  obsolete ;  lateral  valve  turgid- 
lanceolate,  with  conspicuous  pseudo- 
openings.  KSA.  p.  139.  Antarctic  Sea. 
Diam.  1-480". 

Z.  ?Circinus  (B.). — Frustules  minutely 
and  decussately  punctate ;  lateral  valves 
forming  truncated  cones  without  pro- 
cesses, but  each  having  two  long,  seti- 
form,  bent  spines  ;  lateral  view  elliptic. 
BC.  vii.  pi.  1.  £  19,  20.  Fossil.  Vir- 
ginia. Characterized  by  the  conic  out- 
line of  the  lateral  valves,  and  the  absence 
of  nrocesses. 

Z.  Navicula,  EM.  pi.  19.  £  22.  Fossil. 
Greece.  Lateral  valve  oblong,  with 
transverse  rows  of  dots,  a  transverse 
smooth  median  band,  and  a  pseudo- 
opening  at  each  end. 

Z.  paradoxus  (E.). — Smooth,  laterally 
linear-oblong  with  rounded  ends.  EM. 
pi.  22.  £  54.  =  Surirella  paradoxa,  EM. 
Caltanisetta,  Sicily.     1-576". 

Z.  Siculus  (E.).  —  Smooth,  linear ; 
laterally  rhomboid,  with  obtuse  ends. 
EM.  pf.  22.  £  53.  =  Surirella  7'homhoidea, 
EM.     Fossil.     Sicily.     1-744". 

Z.  Mohiliensis  (B.).  —  Frustules  qua- 
drangular, thin,  delicately  punctate; 
valves  with  slender,  tapering  lateral 
processes,  and   two  slight  intermediate 


OF  THE  BIDDULPHIE^, 


851 


projections  armed  with  one  or  two  very 
long  filiform  spines.  BC.  1859.  =^eV/- 
dulphia  Baileyii,  SBD.  ii.  p.  50,  pi.  62. 
f.  322,-  Ro  TMS.  vii.  p.  12,  j)l.  1.  f.  5-9. 
America.  In  stomach  of  Ascidise.  Hull, 
Teignmouth.  (vi.  11.)  Frustules  fra- 
gile, yeUowisli.    A  well-marked  species  j 


there  is  no  central  pro]  ection  of  the  valves, 
but  two  slight  elevations,  furnished  with 
one  or  more  bristles,  and  di\'iding  the 
margin  into  three  nearly  equal  portions. 
The  elevations  appear  situated  between 
the  processes,  but  are  really  placed  on 
opposite  sides. 


Genus  HEMIAULUS  (Ehr.). — Frustules  compressed,  subquadrate  ;  fission 
perfect,  hence  not  concatenate ;  valves  without  lateral  constrictions,  each  with 
two  processes — that  of  the  one  side  (apparently  ?)  open,  the  other  closed.  The 
genus  has  the  habit  of  Biddulphia,  but  is  devoid  of  the  lateral  constrictions. 
It  has  the  form  of  a  Pandean  pipe.  As  the  valves  are  not  constricted,  the 
basal  angles  are  rectangular,  and  the  outer  margins  of  the  processes  (which 
are  generally  attenuated,  narrow,  and  elongated)  are  straight. 


Hemiaulus  antarcticus  (E.). — Frus- 
tules strongly  granular ;  lateral  processes 
elongated,  of  one  valve  truncate,  of  the 
other  elongated  j  a  short  median  rounded 
projection  between  the  processes.  EM. 
pi.  35.  A.  22.  f.  15.  Antarctic  Sea.  (xi.  54. ) 
Diam.  1-1152".  Granules  in  parallel 
rows. 

H.  Polycystinorum  (E.). — Angles  ex- 
tended into  very  long,  narrow,  linear, 
horn-like  processes,  which  are  attenuated 
at  the  extremity,  and,  as  well  as  the  base, 
ceUulose.  EM.  pi.  3G.  f.  43.  Barbadoes 
deposit.     Between  the  processes  are  from 


one  to  three  slight  projections ;  lateral 
view  oval,  bordered,  having  transverse 
bars  corresponding  in  number  to  the  de- 
pressions. 

H.  ?  Australis  (E.). — ^Valves  strongly 
granulate ;  lateral  processes  rounded, 
intermediate  one  obsolete.  KSA.  p.  139. 
Antarctic  Sea. 

H.  ?  Californicus  (E.). — Valve  granu- 
late, having  a  subquadrate  base  ;  angles 
extended  into  linear  processes  without 
intemiediate  projections.  EM.  pi.  33. 13. 
f.  15.     In  Califomian  tripoli. 


Genus  ISTHMIA  (Ag.).  —  Frustules  compressed,  trapezoidal,  ceUulose, 
attached,  cohering  by  short  neck-like  processes,  so  as  to  resemble  irregularly 
branched  filaments.  Frustules  always  more  or  less  oblique,  the  lower  angle 
of  each  prolonged  into  a  process  by  which  it  coheres  to  the  one  beneath,  and 
which  in  the  basal  frustule  forms  the  stipes  by  which  the  filament  is  attached. 
The  fi^ustules  are  tui"gid,  and  the  reticulations  of  the  central  portion  smaller 
than  those  of  the  sides. 


IsTHinA  enervis  (E.). — Lateral  valves 
with  large,  somewhat  quadrate  cellules 
arranged  in  transverse  parallel  lines. 
=  Cmiferva  ohliquata,  EB.  t.  1869;  I. 
obliquata,  Ag.  ;  I.  nei'vosa,  KSA.  p.  135 ; 
E  Inf.  p.  209;  pi.  16.  f.  6 ;  SBD.  ii.  p.  52, 
pi.  48.  Europe,  America,  Cape  of  Good 
Hope,  &c.  (x.  183.)  The  lateral  por- 
tions are  separated  from  the  central  one 
by  rather  broad  lines,  produced  by  the 
junction  and  inflection  of  the  margins, 
and  which  form  internally  projecting 
plates  or  rims.  The  cellules  bordering 
the  sutures  are  somewhat  larger  than 
the  other  cellules  of  the  central  portion, 
but  less  remarkably  so  than  in  the  next 
species. 

I.  nervosa  (K.). — Lateral  portions  with 
parallel  transverse  costse,  having  two  or 
more  series  of  hexagonal  cellules  in  each 
interval.  =  Diatoma   obliquatmn,  Lyng.  ; 


I.  obliquata,  E. ;  I.  nervosa^  KA..  135 ; 
SD.  ii.  p.  52,  pi.  47.  Northern  shores  of 
Europe  and  America.  This  is  usually  a 
more  northern  species  than  /.  enervis. 
The  cellules  are  smaller,  except  a  series 
of  large  conical  ones  bordering  the  inner 
side  of  the  sutures,  and  the  frustules  are 
generally  not  so  wdde  in  proportion  to 
their  length;  but  the  most  evident  di- 
stinction is  the  division  of  the  lateral 
portions  into  compartments  by  the  costse, 
which  often  anastomose. 

I.  minima  (Harv.  &  B.). — Central  por- 
tion very  finely  decussately  punctated; 
lateral  portions  granulated  by  large 
cellules.  Proc.  of  Acad,  of  Phil.  Rio 
de  Janeiro  and  Sooloo  Sea. 

Imperfectly  known. 

I.  ?  Africana  (E.). — Large  flat  frag- 
ments resembling  the  central  portions  of 
3i2 


852 


SYSTEMATIC  HISTORY  OF  THE  INFUSOBIA. 


Istlimia,  marked  by  transverse  rows  of  I  ERBA.  1844,  p.  83. 
very    minute    cellules.      Oran,    Africa,  |  frag-ment  1-216". 


Diameter  of  largest 


Genus  HYDEOSERA  (Wallich). — Emstules  quadrate,  united  into  fila- 
ments, and  furnished  with  conspicuoiLS  horizontal  bands  or  septa;  valves 
cellulose,  compressed,  or  triangular,  with  internal  septa,  and,  on  one  side  only, 
with  minute,  aperture-like  appendages.  Marine.  Filaments  elongated, 
attached,  compressed,  or  prismatic.  Joints  rectangular,  connected  at  the 
angles  by  mucoiLS  cushions,  and  marked  by  bands  passing  across  the  valves 
and  connecting  zone.  In  the  lateral  \^ew  the  ends  or  angles  are  separated 
by  septa.  Hydi'osera  seems  allied  on  the  one  hand  to  the  Terpsinoeae,  and  on 
the  other  to  the  Biddulphiese  and  Anguliferese. 


Hydboseba  compressa  (Wallich). — 
Filaments  compressed;  valve  oblong, 
divided  into  three  inflated  compartments 
by  two  transverse  septa.  Wallich,  MJ. 
vi.  p.  252,  pi.  13.  f.  7-11.  East  Indies. 
Side  view  with  blank  angles,  occasionally 
furnished  with  a  few  minute  spines. 
(VI.  8.) 

H.   triqudra  (Wallich).  —  Filaments 


triquetrous ;  valves  triangular,  with  the 
subcircular  centre  di-^ided  from  the  ob- 
tuse, somewliat  produced  angles  by 
septa.  Wallich  MJ.  vi.  p.  251,  pi.  13. 
f.  1-6.  East  Indies.  Front  ^iew  with 
fom*  transverse  bands ;  valves  with  un- 
dulated sides,  reticidated,  except  at  the 
angles,  which  are  furnished  with  a  few 
extremely  minute  spines  (vi.  13.) 


FAMILY  XL— ANGULIFERE^. 

Frustules  cellulose  or  granulate  ;  in  lateral  view  angular.  This  family  is 
closely  allied  to  Biddulphieoe  (and  in  some  manner  connected  with  the  Cosci- 
nodisce^  and  Eupodisceee).  As  in  that  family,  the  lateral  portions  are  seen,  in 
the  front  view,  having  the  central  portion  lil^e  a  band  between  them.  Hence, 
in  order  to  determine  their  proper  family,  it  is  frequently  necessary  to  see 
them  laterally.  The  angles,  however,  in  the  front  view  are  usually  less 
elongated,  and  the  intervening  margin  less  lobed  in  the  AnguHferese  than  in 
the  Biddulphiese. 

Genus  EUODIA,  n.  g.  (Bailey,  MS.). — Frustules  cellulose  or  granulate ; 
in  lateral  view  lunate.  Eiiodia  agrees  with  the  Eunotieae  in  the  shape  of  its 
frustules,  which  can  scarcely  be  called  angular ;  yet,  notwithstanding  that 
resemblance  in  form,  its  punctate  or  granulate  surface  induces  us  to  place 
it  here. 

EuoDiA  gibha  (Bai.  MS.). — Frustules 
in  lateral  view  semilunate,  the  ends 
somewhat  conical,  the  lower  margin 
gibbose  ;  surface  with  radiating  series  of 
minute  granides.  Recent.  Gulf  Stream, 
(vni.  22.)  From  a  drawing  by  Pro- 
fessor Bailey.  The  upper  margin  is  very 
convex,  the  lower  one  less  so.  A  con- 
traction near  the  obtuse  ends  makes 
them  appear  somewhat  produced  and 
conical.  Professor  Bailey  represents  the 
cross  section  as  cuneate.  Goniothecium 
ammlis,  EM.  t.  33.  18.  f.  4,  gi-eatly  re- 


sembles this  species,  and  may  be  iden- 
tical. The  upper  margin,  however,  is 
represented  as  more  convex,  the  ends  less 
produced,  and  the  gTanules  larger  and 
less  numerous. 

E.  ?  BriglihceUii.  —  Frustules  semilu- 
nate, ends  scarcely  produced,  lower 
margin  concave ;  granules  somewhat 
concentric.  =  Triccratium  semicircidare, 
Bri  MJ.  i.  p.  252,  pi.  4.  f.  21.  Bermuda 
earth.  T.  ohtusum,  EM.  pi.  18.  f.  49, 
may  probabl}^  be  referred  to  this  species. 


Genus  HEMIDISCUS  (Wallich). — Frustules  free ;  valves  cellulose,  arcuate, 
with  a  ventral  marginal  nodule;  cellulation  hexagonal,  radiate.  Marine. 
We  doubt  whether  Hemidiscus  be  distinct  from  Euodia,  since  the  only  di- 


OF  THE  A:N-GULIFEE£JE. 


853 


stinction  seems  to  be  the  marginal  nodule  of  the  former, — a  character  perhaps 
overlooked  by  Professor  Bailej. 


PLemidiscus  cuneiformis  (Wallich). — 
Valves  semilimate  ;  venter  Tvdth  a  mar- 
ginal row  of  puncta,  and  slightlv  gibbous 
at   the    middle.      Wallich,  TMS.    viii. 


p.  45,  pi.  2.  f.  3,  4.  Bay  of  Bengal  and 
Indian  Ocean.  Cellulation  distinct, 
largest  at  the  centre.  Connecting  zone 
broadest  at  the  dorsum,     (yr.  14.) 


Genus  TEICERATIUM  (Ehr.).— FrustulesceUulose,  free,  simple ;  in  lateral 
view  triangular  (rarely  with  four  or  five  angles).  This  genus  has  been  well 
illustrated  by  Mr.  Brightwell  in  his  excellent  monographs  published  in  the 
^  Journal  of  Microscopical  Science ; '  so  that  the  sj^ecies  can  be  distinguished 
without  much  difficulty.  His  discovery,  in  more  than  one  species,  of  frustules 
with  four  or  even  wdth  five  angles,  shows  that  in  this,  as  in  several  other  cases, 
the  number  of  parts  do  not  afford  good  generic  distinctions.  We  were  inclined 
to  place  greater  reliance  upon  their  complete  fission ;  but  Professor  Bailey  in- 
formed us  that  he  had  met  mth  catenate  specimens.  Mr.  Brightwell,  indeed, 
says  that  "  the  projection  of  a  connecting  membrane  (central  portion)  beyond 
the  suture  of  the  valve,  which  is  one  of  the  characters  of  the  genus  Amphi- 
tetras,  is  not  seen  in  the  square  forms  of  Triceratium ; "  but  we  greatly  doubt 
the  validity  of  this  distinction.  "  One  of  the  difficulties  attending  the  study 
of  this  genus,  and  the  determination,  especially  in  the  fossil  forms,  of  the 
species,  arises  from  the  difficulty  of  obtaining  perfect  frustules,  and  examining 
them  in  their  front  aspect.  The  imperfect  frustules  present  only  the  end  or 
triangular  wall,  from  which  alone  no  j)erfectly  satisfactory^  specific  character 
can  be  ol)tained  "  (Br.). 

The  descriptions,  unless  otherwise  specified,  apply  to  the  lateral  \iew  of 
the  frustules,  and  are  drawn  up,  with  few  exceptions,  from  Mr.  Brightwell's 
monographs. 


*  Lateral  surfaces  spinous. 

Triceratium  spinosicm  (B.). — Sides 
nearly  straight;  angles  prolonged  into 
horn-like  processes  ;  granides  mhiute ; 
spines  numerous ;  front  view  constricted 
beneath  the  processes.  Silliman's  Jour- 
nal of  Science,  xlvi.  pi.  3.  £  2.  =  T.  seti- 
gerwn,  BC.  1854,  pi.  1.  f.24;  T.  armatum, 
*Pvo  MJ.  ii.  p.  283 ;  T.  tridacti/lum,  Bri 
MJ.  i.  p.  248,  pi.  4.  f  3.  Fossil,  Ame- 
rica; recent,  England,  Florida,  (vi. 
19.)  A  variable  species ;  its  numerous 
spines  and  somewhat  triradiate  form  best 
distinguish  it.  Larger  spines  are  often 
interspersed  among  the  smaller  ones. 

T.  cotnjKtctimi  (Bri.  MS.).  —  Spinous ; 
fi'ont  view  constricted  beneath  the  some- 
what inflated  processes  ;  central  portion 
bordered  by  a  series  of  large  cellules.  = 
T.  armatum,  /3,  Bri  MJ.  iv.  p.  274,  pi.  17. 
f  11.  Recent.  Australia.  Smaller  than 
T.  spinosum,  but  like  it  in  form,  having 
a  spine  on  the  middle  of  each  side.  In 
the  front  \'iew  it  is  very  different. 

T.  comferum  (Bri.).  —  "  Sides  uTegu- 
larly  concave ;  angles  drawn  out  into  an 
extended  cone  with  a  short,  stout  horn 
near  each :    centre   of  frustule   convex, 


with  three  setae."  Bri  MJ.  iv.  p.  274, 
t.  17.  f  6.  Shell  cleanings.  The  mani- 
niillate  angles,  giving  the  sides  a  waved 
appearance,  mark  the  species.  The  gra- 
nules are  not  radiant. 

T.  contortum  (Sh.). — Angles  prolonged 
into  curved  horn-like  processes ;  spines 
in  three  radiate  double  rows,  terminating 
near  each  angle  with  a  long  bristle.  Sh 
TMS.  ii.  p.  15,  pi.  1.  f.  7.  Recent.  Natal. 
(yi.  18.)  Well  distinguished  by  its  con- 
torted angles.     Sides  straight. 

T.  orhiculatmn  (Sh.). — Sides  convex ; 
angles  obtuse,  each  with  a  circular 
pseudo-nodule  accompanied  by  a  spine  ; 
gi-anules  minute,  radiating.  Sh  TMS.  ii. 
p.  15,  pi.  1.  f  6.  Natal.  The  front  view 
shows  the  narrow  central  portion  marked 
like  the  lateral  portions,  which  are  large, 
not  constricted,  and  terminated  by  three 
truncated  cones.  Mr.  Brightwell  enter- 
tains no  doubt  as  to  the  identity  of  his 
specimens  with  Mr,  Shadbolt's  species  ; 
yet  the  latter's  figure  has  no  spines,  and 
he  describes  "the  margin  being  so  in- 
flated as  to  cause  the  triangular  outline 
to  approach  that  of  the  circle." 

T.  Mari/landicum  (Bri.). — Sides  nearly 
straight,  with  rounded  angles,  without 


854 


SYSTEMATIC  HISTORY  OF  THE  rNTUSORIA. 


pseudo-nodules ;  granules  minute,  radi- 
ating from  an  angular  umbilicus  ;  spines 
few,  marginal.  Bri  M J.  iv.  p.  275,  pi- 17. 
f.  17.  Maryland  deposit.  There  is  at 
each  angle  a  short  spine,  and  sometimes 
another  at  the  middle  of  each  margin. 
Professor  Bailey  regards  this  species  as 
identical  with  T.  Amhlyoceros -,  but  we 
cannot  believe  that  Ehrenberg  would 
have  omitted  so  remarkable  a  character 
as  the  angular  umbilicus,  nor  are  both 
species  found  in  the  same  deposit.  We 
have  already  given  our  reasons  for  doubt- 
ing the  correctness  of  the  supposition 
that  Ehrenberg  foimded  his  Symholo- 
phora  Trinitatis  upon  this  species. 

T.  annidatum  (Wallich). — Valve  mi- 
nute, with  slightly  produced  rounded 
angles  and  concave  sides ;  surface  marked 
with  concentric  rings,  and  a  ray  proceed- 
ing from  the  centre  towards  each  angle. 
Ganges.  WaUich,  MJ.  vi.  p.  249,  pi.  12. 
f.  15.  Valves  covered  with  minute 
puncta,  aggregated  into  concentric  rings. 

2  *  Lateral  surfaces  with  radiating 
vein-like  lines. 

T.  radiatum  (Bri.).  —  Sides  straight ; 
angles  obtuse ;  radiating  lines  most  evi- 
dent at  centre  and  margin;  granules 
minute,  radiating.  Br.  I.  c.  p.  275,  pi.  17. 
f.  14.  Barbadoes  deposit.  Frustules 
large,  without  horn-like  processes. 

T.  marginatum  (Br.).  —  Valves  ^dth 
a  triangular  centre,  which  is  surrounded 
by  a  broad  border  divided  into  compart- 
ments by  short  transverse  lines.  Br  MJ. 
iv.  p.  275,  pi.  17.  f.  13.  Fossil.  Sides 
straight,  angles  with  double  pseudo- 
nodides ;  granules  of  centre  minute, 
radiating,  those  of  compartments  larger 
and  scattered. 

T.  venosum  (Br.).  —  Sides  concave  ; 
angles  rounded,  smface  dotted,  and 
marked  by  three  radiating  pinnated  lines 
or  veins,  (vi.  17.)  Br  MJ.  v.  p.  274, 
pi.  17.  f.  5.  Barbadoes  deposit.  A  very 
beautiful  and  distinct  species. 

T.  tahellarium  (Br.). — Margin  indented 
in  foliaceous  curvatures ;  granides  nume- 
rous near  the  margin,  elsewhere  in 
patches;  angles  with  small  horns.  Br 
MJ.  iv.  p.  275,  pi.  17.  f.  15.  Honduras. 
This  species  is  well  distinguished  by  its 
scolloped  margin.  It  is  doubtful  whe- 
ther it  is  properly  placed  in  this  section. 

T.  variahile  (Br.).  —  Surface  with  a 
transverse  line  below  each  angle,  and 
f  ome  irregular  radiating  veins  :  granules 
scattered,  indistinct  at  the  angles.  Br 
MJ.  iv.  p.  275,  pi.  17.  f  19.      Peruvian 


guano.  Resembles  T.  aUernans,  but  is 
larger  and  generally  distorted ;  the  angles 
are  conical.  Mr.  Brightwell  figm-es  a 
quadrangular  form  of  this  species. 

T.  truncatum  (Br.). — Angles  elongated 
into  broadly  truncate  arms,  centre  di- 
vided into  granulated  compartments  by 
radiating  vein-like  lines.  Br  MJ.  iv. 
p.  274,  pi.  17.  f.  4.  Barbadoes  earth. 
Frustules  triradiate. 

3*  Lateral  surfaces  with  transverse  lines 
separating  the  angles  from  the  hexagonal 
centre. 

T.  hrachiatum  (Br.). — Trii*adiate  ;  an- 
gles elongated  into  truncate  arms,  and 
separated  from  centre  by  transverse  lines. 
Br  M J.  iv.  p.  274,  pi.  17.  f.  3.  Barbadoes 
earth.  Distinguished  by  its  angles  pro- 
longed into  rays.  It  resembles  T.  trun- 
catum in  form,  but  is  smaller,  and  has  no 
radiating  veins. 

T.  aUernans  (Bai.).  —  Sides  straight, 
angles  obtuse,  granulated  like  the  hexa- 
gonal centi-e.  SBD.  i.  p.  26,  pi.  5.  f.  45. 
Common,  recent  and  fossil.  England, 
United  States  guano,  (vi.  21.)  Front 
view  quadrate,  not  constricted ;  the 
angles  not  prolonged  into  processes. 

T.  trisulcum  (Bai.  MS.).  —  Sides  very 
concave ;  angles  broadly  rounded,  sepa- 
rated from  centre  by  transverse  lines; 
granules  crowded  and  very  minute  at 
angles,  elsewhere  few,  large,  and  scat- 
tered. (\t:ii.  27.)  From  a  drawing  by 
Professor  Bailey.  Gulf-stream  shells, 
W.  Indies.  This  species  may  be  kno^vu 
by  its  distant  granides. 

T.  castellatum  (West). — Sides  of  the 
frustule  deeply  concave  ;  angles  forming 
segments  of  circles.  Valves  with  con- 
cave sides  and  roimded  angles,  forming 
dome-shaped  eminences;  surface  pimc- 
tate,  with  a  single  row  of  larger  puncta 
along  the  opposed  margins.  West,  TMS. 
viii.  p.  148,  pi.  7.  f.  3.  Barbadoes  deposit, 
(viii.  29.) 

T.  Johnsoni  (Ralfs,  n.s.). — Valves  with 
rounded  angles  and  concave  sides,  sm-- 
face  with  scattered  granules,  and  a  large 
granulated  space  at  the  angles,  separated 
by  a  transverse  smooth  band ;  margin 
with  a  few  short  lines.  Barbadoes  de- 
posit. Johnson.  Valves  large,  with 
conspicuous  gTanules,  which  are  few  at 
the  centre,  and  more  numerous  near  the 
margin  ;  each  side  with  a  few  short  strise 
like  those  figured  by  Mr.  BrightweU  in 
T.  tahellarium,  but  the  margin  itself  is 
not  undulated. 

T.  umhilicatum  (Ralfs,  n.s.). — Valves 


OF  THE  AXGrLIFEKEiE. 


855 


witli  broadly  rounded  angles  and  deeply 
sinuated  sides,  triangular  smooth  um- 
bilicus, radiant  series  of  close  granules, 
and  a  large  punctate  space  at  each  an- 
gle. Barbadoes  deposit.  Johnson.  This 
large  and  beautiful  species  is  distin- 
guished by  the  sinuated  sides  and  tri- 
angular umbilicus  of  the  valves.  Gra- 
nules conspicuous  and  dense,  appearing 
both  radiant  and  concentric.  The  large 
angles  are  separated  by  indistinct  trans- 
verse lines,  and  appear  smooth  or  granu- 
lated according  as  they  are  more  or  less 
in  focus,  and  they  have  a  central  round 
spot  (probably  a  process)  and  sti-iated 
margin.  This  species  diifers  from  T. 
castellatum  in  a  distinctly  radiant  ar- 
rangement of  the  granules  and  a  smooth 
mnbilicus. 

T.  megastofnum  (E.). — Sides  straight; 
angles  obtuse,  with  pseudo-nodides,  and 
separated  by  transverse  lines  from  the 
hexagonal  centre.  EM.  pi.  35.  In  guano. 
Small,  somewhat  resembling  T.  Reticulum, 
but  diifering  in  its  pseudo-nodules  and 
hexagonal  centre. 

4*  Sides  in  lateral  view  (/ibbous  or  un- 
dulate {angles  without  pseudo-nodules; 
cellules  minute). 

T.  undalatum  (E.).  —  Sides  slightly 
convex,  undidated ;  granules  minute, 
radiating.  Br  MJ.  i.  p.  250,  pi.  4.  f.  13 ; 
ERBA.  1840,  p.  273.  Fossil.  Bermuda 
and  Virginian  deposits. 

T.  Brightivellii  (West).  —  Sides  of 
valves  undulate,  slightly  convex,  or 
straight ;  granules  minute,  radiating 
from  the  centre,  from  which  proceeds  a 
spine  of  considerable  length ;  margin  of 
valve  closely  set  with  short  spines.  =  T. 
uadulatum,  Br  MJ.  vi.  p.  154,  pi.  8. 
f.  1-5,  8 ;  West,  TMS.  viii.  p.  149,  pi.  7. 
f.  6.  Var.  i3  with  4  angles.  In  Noctilucae. 
England.  The  discovery  of  this  and  the 
following  species  in  a  living  state  has 
explained  the  appearance  of  the  central 
pseudo-nodule,  which  has  proved  to  be 
the  remains  of  a  long  horn  or  spine. 

T.  intricatum  (West). — Sides  of  valves 
undulate ;  angle  acute  and  slightly  pro- 
duced ;  centre  tumid  ;  granules  in  lines, 
radiating  from  the  centre,  scarcely  dis- 
cernible ;  pseudo-nodule  apparent.  =  T. 
striolatum  P,  SBD.  i.  p.  27,  pi.  5.  f.  46 ;  T. 
undulaium,  Bri.  /.  c.  ;  West,  TMS.  viii. 
p_.  148,  pi.  7.  f.  5.  This  species  in  its 
living  state  forais  short  filaments  united 
in  a  distant  series. 

T.  striolatum  (E.).  —  Sides  convex, 
slightly  undulated;  angles  attenuated, 
ending  in  minute  papiUee.      KB.  t.  18. 


f.  10.  =  T.  mc7nhranaceum,  Br  MJ.  i.  pi.  4. 
f.  15.  Thames  mud,  Cuxhaven.  Walls 
of  the  frustule  extremely  delicate,  dotted 
over  with  very  minute  cellules. 

T.  Parmula  (Br.).  —  Sides  gibbous, 
with  produced  mammiform  angles  ;  sur- 
face minutely  punctated.  Br  MJ.  iv. 
p.  275,  pi.  17.  f.  2.  Natal.  Var.  /3  with 
4  angles.  West,  TMS.  viii.  p.  147,  pi.  7. 
f.  1.  Frustules  minute,  in  outline  re- 
sembling a  shield. 

T.  Americana. — Sides  convex,  slightly 
undidated ;  angles  rounded ;  cellules 
minute.  =  T.  Amhlijoceros  ?,  Br  MJ.  i. 
p.  250,  pi.  4.  f.  14.  Fossil.  Richmond, 
Virginia.  The  roimded  angles  without 
appendages  distinguish  this  species  from 
the  others  in  this  section. 

T.  margaritaceum  (Ralfs,  n.  s.).  — 
Valves  with  rounded  angles,  and  straight 
or  slightly  convex  sides  ;  smface  with 
conspicuous  pearly  granules,  which  are 
scattered  at  a  triradiate  central  space, 
and  arranged  in  radiating  lines  at  the 
margin.  Barbadoes  deposit.  Johnson. 
The  valve  is  bordered  by  a  row  of  larger 
gi'anules ;  and  only  a  narrow  inconspicu- 
ous temiinal  portion  of  the  angles  appears 
smooth. 

T.  gihhosum  (Harv.  &  Bail.). — ^^Almost 
inflato-globose,  the  sides  very  convex, 
angles  prominent ;  sm-face  marked  as  in 
T.  concavum.''''  Small.  Proc.  of  Acad, 
of  Nat.  Sci.  Philadelphia,  1853.     Tahiti. 

5*  Frusttdes  not  spijious,  sulcate,  veined^ 
nor  undulate. 

t  Cellules  large,  hexagonal. 

T.  Favus  (E.).  —  Sides  straight  or 
slightly  convex ;  angles  obtuse,  with 
horn-like  processes ;  surface  reticidated 
with  large  hexagonal  cellules,  (xi.  43, 
U::)  =  T.meqastomum,'Bv'SU.  i.  pi. 4.  f.7?; 
T.  fmhriaium,  WaUich  MJ.  vi.  p.  247, 
pi.  12.  f.  4-9.  Recent  and  fossil,  not 
uncommon.  Diam.  1-200''  to  1-150". 
Front  view  ^vitll  the  central  portion  mi- 
nutely pimctated,  the  lateral  portions 
scarcely  constricted  beneath  the  short 
stout  processes.  Mr.  Brightwell  figures 
a  quadi-ilateral  form  of  this  species  with 
concave  sides. 

T.  serratum  (Wallich). — Valves  (qua- 
diilateral)  furnished  Avith  a  hom-like 
process  at  each  angle,  and  from  4  to  6 
elongated  scattered  spines,  with  furcate 
apices  ;  sides  or  plates  of  connecting  zone 
joined  bv  dovetailed  margins.  Wallich, 
MJ.  vi.  p.  243.  pi.  12.  f.  1-3.  St.  Helena. 
Connecting  zone  as  well  as  valves  marked 
with  a  delicate  but  well-denned  hexa- 


S5Q 


SYSTEMATIC  HISTORY  OF  THE  INFirSORlA. 


gonal  areolation.  This  species  is  re- 
markable chieiiy  for  the  peculiar  struc- 
ture of  its  conuectiug  zone,  the  plates 
having-  their  communicating  margins 
serrated  so  as  to  fit  into  each  other. 

T.  grande  (Br.).  —  Sides  convex ; 
angles  attenuated,  obtuse;  hexagonal 
cellules  numerous.  Diam.  1-100".  Br 
MJ.  i.  p.  249,  pi.  4.  f.  8.  T.  orientale, 
Harv.  &  Bail.  I.  c.  Indian  Seas,  Min- 
danao. "  The  largest  and  stoutest  spe- 
cies of  this  genus  "  (Br.).  The  descrip- 
tions do  not  suffice  to  distinguish  this 
species  from  large  specimens  of  T.  Favus. 

T.  muricatum  (Br.). — Sides  straight ; 
angles  ending  in  a  stout  horn-like  pro- 
cess ;  cellules  large,  hexagonal.  Br  M J.  i. 
p.  249,  pi.  4.  f  5.  From  the  cleanings  of 
shells.  A  minute  species,  distinguished 
by  its  pointed  angles.  Front  view  nearly 
square,  with  the  central  portion  smooth, 
and  the  lateral  ones  turgid  between  the 
prominent  processes. 

T.  ocellatum  (E.). — Sides  slightly  con- 
cave ;  angles  attenuated,  obtuse ;  cellules 
unequal,  large,  hexagonal  in  the  centre, 
gTadually  becoming  smaller  at  the  sides, 
in  no  distinct  order.  KSA,  p.  141. 
Mouth  of  River  Tenasserim,  India. 

2t  Lateral  surfaces  with  three  pseudo- 
nuclei,  not  situated  at  the  angles. 

T.  sciilptmn  (Sh.).  —  Sides  straight ; 
angles  prolonged  into  conical  points; 
granules  scattered ;  surface  with  three 
circular  pseudo-nuclei,  one  opposite  the 
middle  of  each  side.  Sh  MT.  ii.  pi.  1. 
f  4.  Natal,  In  form  this  species  some- 
what resembles  T.  aciitmn;  but  its  pseudo- 
nuclei  are  eminently  characteristic. 

3t  Frustides  triradiate,  with  very 
concave  sides. 

T.  Solenoceros  (E.). — Triradiate,  with 
deeply  concave  sides;  angles  prolonged 
into  long,  linear,  obtuse  arms;  cellules 
radiating.  Br  MJ.  i.  p.  248,  pi.  4.  f  1. 
Bermuda  earth,  (vi.  15.)  This  species 
differs  from  every  other  by  its  long  linear 
rays,  which  have  neither  pseudo-nodules 
nor  processes. 

T.  Pileus  (E.). — Somewhat  triradiate, 
with  very  concave  sides ;  angles  tapering, 
obtuse,  with  pseudo-nodules ;  cellides 
minute,  radiating.  EM.  pi.  19.  f.  18.  =  T. 
brachiolatmn,  Br  MJ.  i.  pi.  4.  f  2.  Fossil, 
Greece ;  recent.  New  Zealand.  Mr. 
Erightwell  refers  his  T.  hrachiolatum  to 
the  next  species. 

T.  PUeohis  (E.).  —  Somewhat  trira- 
diate, with  vcrv  concave   sides :  angles 


produced,  obtuse,  with  pseudo-nodules ; 
cellides  small,  scattered.  EM.  pi.  35  a. 
21.  f.  17.  =  T.  obtusum,  Br  MJ.  iv. 
p.  251,  pi.  4.  f.  20.  Antarctic  Ocean. 
Resembles  T.  Pileus  in  form,  but  is 
smaller,  and  its  cellules  are  scattered. 

4t  Frustules  not  triradiate ;  angles  with 
pseudo-nodules,  or  minutely  punc- 
tated. 

T.  concavum  (Harv.  &  Bail.). — Sides 
very  concave  ;  angles  rounded,  minutely 
punctated;  cellules  of  centre  arranged 
in  simple  and  forked  radiating  lines. 
H.  &  B.,  Trans,  of  Acad,  of  Philadelphia, 
1853.    Tahiti. 

T.  WaUiclui  (Ralfs).  ~  Valves  with 
minute  radiate  areolation,  a  row  of  mar- 
ginal puncta,  and  a  minute  horn-like 
process  at  each  angle.  =  T.  imnctutuin^ 
Wallich,  TMS.  viii.  p.  48,  pi.  2.  f.  21. 
India,  Atlantic. 

T.  arcticum  (Bri.).  —  Valves  with 
slightly  convex  or  straight  sides ;  areo- 
lations  small,  but  distinct,  radiating  in 
lines  from  the  centre,  and  becoming  mi- 
nute at  the  angles,  which  are  rounded 
and  slightly  inflated.  =  T.  Wilkesii,  var. 
/3,  ■v\ath  4  angles ;  Amphifetras  Wilkesii^ 
Bri  MJ.  i.  p.  250,  pi.  4.  f  11;  Ro  TMS. 
viii.  p.  58.  Beechey  Island,  Arctic 
Regions;  Puget's  Sound,  Vancouver's 
Island ;  and  Montery  stone.  The  speci- 
mens obtained  from  Vancouver's  Island 
have  proved  that  Triceratium  has  been 
erroneously  considered  a  free  form,  and 
that  its  proper  position  is  with  Amphi- 
tetras  and  Biddulphia;  the  specimens 
alluded  to  show  it  attached  to  Zoo- 
phytes, and  the  frustides  connected  at 
the  angles  by  a  short  stipes  or  cushion, 
exactly  like  Amphitetras. 

T.  Montereyii  (Br.). — Sides  concave  ; 
angles  rounded,  with  pseudo-nodules; 
cellides  minute,  largest  in  the  centre, 
which  is  much  inflated.  Br  MJ.  i.  p.  251, 
pi.  4.  £  8.  Fossil.  Monterey  Bay.  This 
species  is  easily  distinguished  from  T. 
arcticum  by  its  central  boss  and  larger 
cellules. 

T.  punctatmn  (Br.).  —  Sides  straight ; 
cellules  large,  puncta-like,  scattered, 
smaller  at  the  rounded  angles.  Br  MJ. 
iv.  p.  275,  pi.  17.  f.  18.  Arctic  Regions. 
(VI.  20.) 

5t  Angles  without  pseudo-nodules. 

T.  formosum  (Br.).  —  Sides  slightly 
concave ;  angles  obtuse,  without  pseudo- 
nodules  ;  cellules  very  minute,  somewhat 
radiating.  Br  INI  J.  i.  p.  250,  pi.  4.  f  10. 
Shell  cleanings  from  i/?)?^?o^)?<5  macuJatKS, 


OF  THE  ANGFLIFEREJE. 


857 


Mr.  Brightwell  finds  this  species  varj^ng, 
with  four  and  five  angles.  The  front 
view  is  quadrate,  not  constricted,  the 
angles  produced  into  conical  processes, 
between  which  the  margin  is  nearly 
straight. 

T.  condecorum  (E.). — Sides  straight 
or  slightly  convex,  with  obtuse  angles ; 
cellules  ver}'  minute,  diverging  in  curved 
series.  Br  MJ.  i.  p.  250,  pi.  4.  f.  12. 
Fossil.     Bermuda. 

T.  ohtusum  (E.). — Sides  very  convex; 
angles  rounded,  without  pseudo-nodules ; 
cellules  circular,  scattered.  EM.  pi.  18. 
f.  48,  49.     Virginia. 

T.  Amhlyoceros  (E.). — Sides  concave  ; 
angles  broadly  rounded,  without  pseudo- 
nodules  ;  cellules  minute,  somewhat 
radiating.  EM.  pi.  18.  f.  51.  Virginia. 
This  species  has  more  rounded  angles 
and  smaller  cellules  than  T.  obtusum. 

T.  Reticulum  (E.). — Sides  straight ; 
angles  subacute, vvdthout  pseudo -nodules ; 
cellules  minute,  numerous.  EM.  pi.  18. 
f.  50.  Fossil,  America;  recent  from 
sheU-cleanings.  Front  view  with  a  nar- 
row, smooth  central  zone;  lateral  sur- 
faces not  constricted  beneath  the  slightly 
prominent  angles. 

T.  acutum  (E.). — Sides  nearly  straight; 
angles  elongated  into  points ;  cellules  not 
radiating.  Br  MJ.  i.  p.  251,  pi.  4.  f.  16. 
Bermuda.  T.  acutum  is  somewhat  tri- 
radiate  from  its  acimiiuated  angles. 

Doubtful  or  insufficiently  hnown  Species. 

T.  scitulum  (Br.). — "A  small  species, 
but  vaiying  in  size.  On  some  of  the 
fi'ustules  I  have  reckoned,  on  an  end 
view,  about  45  cells  only ;  sides  very 
slightly  convex;  angles  open.  Diam. 
1-350''."  Br  MJ.  i.  p.  250,  pi.  4.  f.  9. 
Indian  Ocean.  Varies  wdth  foui'  sides. 
Except  in  its  smaller  size,  we  see  not  how 
this  species  differs  from  T.  Farus. 

T.  Africanum  (E.).  —  Sides  convex  ; 
angles  rounded;  cellules  large,  in  radi- 
ating series.  EM.  pi.  35  b.  19.  f.  1. 
Eecent.  West  Africa.  In  form  resem- 
bles T.  ohtusum. 

T.  comptum  (E.). — Sides  straight,  and 
having  a  marginal  fringe ;    angles  pro- 


longed into  short,  stout  spines ;  cellules 
large,  hexagonal.  Eo  MJ.  ii.  p.  283,  f.  2. 
England.  "The  cellular  markings  are 
as  large  as  in  T.  Favus,  and  I  am  rather 
doubtfid  whether  it  may  not  be  a  young 
form  of  that  species ;  but  the  length  of 
the  processes,  and  fringe-lilie  row  of  cells 
at  the  margin,  appear  to  give  it  a  di- 
stinctive character  "  (Eoper). 

T.  crassum  (Sh.).  —  "Much  smaller 
than  T.  contortum.  Is  characterized  by 
the  reticulations  being  coarse  and  irre- 
gular in  form,  and  the  honis  very  large 
as  compared  with  the  size  of  the  valve." 
Sh.  in  TMS.  ii.  p.  15.     Natal. 

T.  hyalinum  (Br.).  —  "  Small,  trans- 
parent, sm-face  with  very  minute  dots  or 
cellules;  sides  regular  and  straight." 
Br  M J.  iv.  p.  275,  pi.  17.  f.  16.  Barbadoes. 
=  T.  Reticulum. 

T.  arcuaium..  —  Sh  T31S.  ii.  pi.  1.  f.  5. 
Natal.  The  figm-e  resembles  that  of  T. 
Pileus,  but  without  pseudo-nodides.  It 
is  probably,  however,  the  same. 

T.  exiguum  (Sm.). — Triradiate:  angles 
elongated  into  linear  truncated  pro- 
cesses ;  celkdes  very  minute,  scattered. 
SD.  ii.  p.  87;  Br  MJ.  iv.  p.  274,  pi.  17. 
f.  1.  Fresh  water.  Ormsb3^  Norfolk. 
(VI.  14.) 

T.  Pentacrinus  (Wallich).  —  Valves 
slightly  convex,  with  5  angles,  with 
a  short  horn  at  each  angle.  Sm-face 
spinous,  divided  into  compartments  by 
anastomosing  lines  or  costae,  which  radi- 
ate irregidarly  fi'om  the  centre.  Var.  /3 
with  4  angles,  y  with  6  angles.  A^'allich, 
MJ.  vi.  p.  251,  pi.  12.  f.  10-14.  St. 
Helena.  We  scarcely  see  how  this  form 
differs  from  Amjihitetras  ornata  of 
Shadbolt.  ^ 

T.  duhium  (Br.).  —  Valve  minute, 
clypeate,  with  6  angles,  the  lower  one 
much  produced;  surface  of  valve  coarsely 
punctate.  Br  MJ.  vii.  p.  180,  pi.  9. 
f.  12.  Mauritius,  Californian  gaiano, 
India.  "  We  place  this  form  (which  is 
not  of  unfrequent  occun-ence)  provi- 
sionally among  the  Triceratia.  It  pro- 
bably forms  the  tvpe  of  a  new  genus  " 
(Br.  /.  c). 

T.  Malleus,  Br  MJ.  vi.  p.  164,  pi.  8. 
f  6.     Not  Diatomaceous  ? 


Genus  AMPHITETEAS  (Ehr.).  — Frustiiles  cellulose,  cubiform,  cohering 
into  a  zigzag  attached  filament ;  in  lateral  view  quadrangular,  -svith  a  pseudo- 
opening  at  each  angle.  Since  Mr.  BrightweU's  discovery  of  quadrangular 
states  of  Triceratium,  the  only  remaining  distinction  between  that  genus  and 
the  present  is,  that  in  this  the  frustiiles  form  catenate  attached  filaments ; 
but,  according  to  Professor  Bailey  (as  already  noticed),  even  this  character  is 


858 


ST8TEMATiC  HISTOEY  OF  THE  INFUSORIA. 


not  confined  to  Amphitetras.  Professor  Smith,  indeed,  remarks,  "  The  pro- 
jection of  the  connecting  membrane  beyond  the  suture  of  the  valve  is  a  cii-- 
cumstance  which  meets  us  for  the  first  time  in  Amphitetras ;  "  but  we  believe 
that  this  occurs  in  every  genus  in  which  the  new  portions  of  the  dividing 
frustiiles  are  formed  within  the  persistent  central  portion,  and  in  this  respect 
there  is  no  perceptible  diiference  between  Triceratium  and  Amphitetras.  As 
some  species  have  been  placed  in  Amphitetras  solely  on  account  of  their 
quadrate  form,  the  correctness  of  their  position  is  consequently  not  free  from 
doubt. 


Amphitetras  antediluviana  (E.).  — 
Lateral  view  with  straight  or  concave 
margins ;  angles  roimded,  each  with  an 
apparent  opening ;  cellules  large,  radiat- 
ing, and  concentric.  Living,  Denmark, 
England,  America,  &c. ;  fossil,  Oran, 
Greece.  (xi.  21,  22.)  A.  tessellata, 
Sh  TMS.  ii.  /3,  sides  very  concave ; 
the  cellules  on  the  central  portion  are 
smaller,  and  arranged  in  longitudinal 
lines. 

A.  Adriatica  (K.)- —  "  Lateral  view 
quadrate;  cellules  radiating  and  con- 
centric; primary  sides  plane."  KSA. 
p.  134.     Adriatic  Sea. 

A.  parallela  (E.). — Cellules  in  lateral 
\dew  large,  arranged  in  parallel  lines. 
Fossil.     Greece. 

A.  crucifem  (Kitton,  n.  sp.). — Valves 
punctate,  and  marked  by  a  line  passing 
from  the  centre  to  each  angle.  Front 
view  deeply  constricted  on  either  side  of 
connecting  zone.  Valves  minute,  with 
slightly  convex  sides,  and  produced 
mammiform  angles.  Cleanings  of  shells 
from  West  Indies.  Distinguished  by 
the  cruciform  lines  of  the  valve,  which 
taper   fi'om   the    centre   to    the  angles. 


where  they  terminate   in   points.     We 
have  seen  4  or  5  frustules  connected  by 


the  angles. 


Doubtful  or  imperfectly  known  Species. 

A.  ornata  (Sh.).  —  "Size  small,  mar- 
gins concave,  and  folded  so  that  each 
valve  is  not  imlike  in  form  to  a  col- 
legian's cap ;  surface  somewhat  iiTegu- 
larlv  ornamented  with  delicate  vein-like 
markings."  TMS.  ii.  p.  16,  pi.  1.  £  10. 
Natal.  Var.  /3,  with  5  angles,  (vm.  16.) 
This  is  probably  a  state  of  some  veined 
species  of  Triceratiimi. 

A.  favosa  (Harv.  &  Bail.). — "  Sides 
scarcely  concave  ;  lateral  view  quadran- 
gular ;  angles  almost  straight,  scarcely 
produced ;  surface  tessellated  with  large 
hexagonal  cellides."  Proc.  of  Acad,  of 
Philadelphia,  1853.     Mindanao. 

A.  Crux  (Bri.).  —  Valves  cruciform, 
with  the  angles  widely  rounded  ;  sm-face 
coarsely  punctate.  Cleanings  from  shells, 
West  Indies;  Californian  guano.  Bri 
JMS.  vii.  p.  181,  pi.  9.  f.  13.  This  may 
be  a  4-angled  var.  of  Triceratium  castel- 
lation  or  T.  trisulcuni. 


Genus  AMPHIPENTAS  (Ehr.). — Frustules  free,  simple,  cellulose  or  gra- 
nulate, pentagonal.     Probably  pentagonal  forms  of  Triceratium. 


AisiPHiPENTAS  aUernans  (E.). — Sides 
concave;  angles  obtuse;  the  angles  of 
the  external  pentagon  alternating  with 
those  of  a  smaller  central  one,  which  has 
a  circular  umbo  at  its  middle.  KA. 
p.  134 ;  EA.  p.  122,  pi.  2.  6.  f.  9.  Cuba. 
(XI.  32.) 

A.  Pentacrinus  (E.). — Pentagonal ;  its 
dorsal  sm-face  presenting  a  striated  ring. 
Diam.  1-240".  KA.  p.  134.  Fossil. 
Greece.     Fragments  like  Amphitetras. 


K.jiexuosa  (B.  MS.).  —  Sides  four  or 
five,  gibbous ;  angles  conical ;  sm'face 
flat;  cellules  hexagonal,  covered  by 
minute  puncta.  Gulf-stream,  (a'i.  22.) 
From  drawings  by  Professor  Baile3\ 
"  Under  a  low  power,  the  markings 
appear  circular,  as  represented  in  the 
figures"  (B.  j.  The  margins  are  undulated 
in  consequence  of  their  gibbous  projec- 
tions, as  in  Triceratium Pannula,  and  may 
be  4-  and  5-angled  forms  of  that  species. 


FAMILY  XIL— TEEPSINOE^. 

Frustules  quadrangular,  smooth,  compressed,  fui^nished  with  unequal  trans- 
verse costae  or  incomplete  sej)ta  interrupted  at  the  middle.  We  have  sepa- 
rated this  small  group  from  Striatelleae  because,  notwithstanding  the  great 


01'  THE  TERPSINOEiE. 


859 


external  resemblance  of  their  solitary  frustiiles,  we  believe  them  to  differ 
essentially  in  structure.  In  StriatelleaB  the  septa  are  longitudinal,  and  divide 
the  central  portion  into  chambers.  In  Terpsinoe86  they  are  transverse  and 
confined  to  the  lateral  portions,  which  appear  in  the  front  view  as  in  Biddul- 
phiese.  The  relation  of  Terpsinoeas  to  the  latter  was  pointed  out  by  Mcne- 
ghini.  The  smooth  frustules  and  straight  lateral  margins  without  processes 
distinguish  the  Terpsinoeae. 

Genus  ANAULrS  (Ehr.). — Frustules  simple,  subquadrate,  smooth  ;  septa 
lateral,  unequal,  not  thickened  at  their  extremities;  lateral  view  oblong, 
Anaiilus  resembles  Biddulphia,  but  its  costae  or  septa  are  unequal,  and  it  has 
no  tubular  processes.  A  genus  of  Mollusks  has  been  also,  but  more  recently, 
called  Anauius. 


Anaulus  scalaris  (E.).  —  Tm-gid  in 
the  young  state;  but  when  full-grown 
very  wide  and  much  flattened,  having 
4,  6,  8,  or  14  lateral  constrictions  ;  late- 
rally oblong  with  transverse  bars,  giving 
it  a  ladder-like  appearance.  EM.  pi.  35  a. 
22.  I  1,  2.  Antarctic  Sea.  Diam.  1-480" 
to  1-180".  The  lateral  valves,  in  the 
front    view,   have    undidated    margins, 


caused  by  the  constrictions,    (viii.  37.) 

A.  Campijlodiscus  (E.).  —  Quadrangu- 
lar ;  each  valve  very  much  compressed, 
triangular,  with  obtuse  angles,  and  hav- 
ing laterally  two  slight  constrictions. 
Bermuda.  Diam.  1-372".  It  has  the 
habit  of  an  unequal-sided  Triceratium  or 
of  a  Campylodiscus. 


Genus  TERPSINOE (Ehr.). — Frustules  concatenate;  cost«  unequal,  capi- 
tate, cuiwed  so  as  to  resemble  musical  notes.  "  If  we  imagine  a  series  of 
frastules  of  Tabellaria  joined  together,  not  laterally,  but  the  head  of  one  to 
that  of  another,  or  in  the  direction  of  breadth  instead  of  length,  we  shall 
form  the  most  just  idea  of  this  genus  "  (Ehr.).  The  capitate  costae,  which 
in  their  form  so  greatly  resemble  musical  notes,  distinguish  Terpsinoe  from 
every  other  genus. 

We  unite  Tetragramma  with  Terpsinoe,  as  Professor  Bailey  finds  the 
"  music-hke  notes"  vary  in  nimiber  from  two  to  at  least  eight  on  a  side, 
and  does  not  consider  theu-  number  even  specifically  important. 

Tehpsinoe  miisica  (E.).  —  Frustules 
finely  punctated,  with  two  or  three  trans- 
verse bands,  the  lateral  valves  having 
costae  in  each  division ;  lateral  view  ob- 
long, showing  two  or  three  infiations  and 
narrower  rounded  ends.  EA.  pi.  3.  4.  £  1 ; 
liab  D.  1. 10.  America,  Africa,  (xi.  47.) 
Frustules  with  finely  punctated  lateral 
portions,  between  which  the  central  zone 
(having  two  puncta  at  each  end)  appears 
like  a  baud.  Two  or  three  bars  cross 
lateral  and  central  portions  from  one 
lateral  margin  to  the  other,  and  divide 
them  obscurely  into  compartments.  The 
lateral  view  has  the  margins  sinuated, 
from  constrictions  corresponding  with 
the  transverse  bands. 

T.  Americana  (Bailey).  —  Frustules 
quadrangular,  resembling  those  of  T. 
musica,  but  smaller,  more  minutely  punc- 
tate, with  two  transverse  bars  and  two 
costse  in  each  lateral  valve.  =  T'etra- 
gromma  Americana,  Bail.  Smithsonian 
Contr.  1853,  p.  7.  f.  1.     As  in  2\  musica, 


the  costae  resemble  notes  of  music,  but 
are  confined  to  the  central  compartments 
of  the  valves.  In  the  lateral  view  it 
resembles  the  preceding  species^  but  has 
fewer  cross-bars. 

T.  Indica  (E.,  Kiitz.).  —  Frustules 
subquadrate  (catenated  ?),  compressed, 
two  or  four  times  constricted;  lateral 
valves  densely  granidate,  central  portion 
smooth,  with  two  puncta  at  each  end ; 
median  costae  dilated  at  the  end.  KSA. 
p.  119.  =  Anaidus  IndicKs,  E.  India, 
frequent. 

T.  Javanensis  (EM.  pi.  34.  8.  f.  16).  — 
The  figure  resembles  T.  musica ;  but  the 
central  portion  is  marked  by  longitudi- 
nal lines,  which  converge  at  each  end. 

Species  known  to  us  only  hy  name. 

T.  Asiatica,  Asia.  =  Tetray7'atntna  Asi- 
atica,  E. 

T.  Japonica  (E.),  Japan. 

T.  Austrahs  (E.),  Sandwich  Islands. 


860 


SYSTEMATIC  HISTOEY  OF  THE  mEUSOEIA. 


T.  Llhyca  —  Tetragramma    Lihycum, 
Africa. 

T.  Brasiliemis  (E.). — Music-like  marks 


According:  to  Elirenberg",  it 


very  small 

approaches  Jl  musica  in  form.     Brazil, 


Genus  PLEURODESMIUM  (Xlitz.).  —  Eriistules  compressed,  connected 
in  fascia-like  filaments  by  short  thread-like  processes ;  lateral  portions 
punctated  and  furnished  with  music-lilie  marks,  the  hyaline  central  smoother 
portion  forming  a  band  between  them. 

Although  Pleurodesmium  was  placed  by  Professor  Kiitzing  in  a  different 
family  from  Terpsinoe,  yet  these  genera  appeared  to  us  so  closely  allied  that 
we  found  it  difficult  to  distinguish  them, — a  difficulty  experienced  also  by 
Mr.  Tuffen  West  on  examining  an  authentic  specimen  of  Pleurodesmium 
given  us  by  our  valued  friend  M.  de  Brebisson,  which,  however,  was  unfor- 
tunately not  in  a  condition  to  afford  a  satisfactory  examination. 

The  frustules,  as  in  Terpsinoe,  agree  with  the  Biddulphieas  in  having  the 
lateral  valves  largely  developed  and  entering  into  the  front  view ;  they  are 
furnished  with  costse,  enlarged  at  the  ends  and  resembling  notes  of  music. 
M.  de  Brebisson  thinks  this  genus  very  distinct,  the  frustules  being  connected 
in  straight  series  by  thread-like  points  of  attachment  proceeding  from  the 
furrows ;  but  these  he  informs  us  are  very  short  indeed,  for  which  reason 
Kiitzing,  like  ourselves,  seems  to  have  overlooked  them. 


Pleurodesmium  Brehissonii  (lAiitz.). 
— Frustules  contracted  at  their  junction ; 
costse  rugose.     KSA.  p.  115.     Cayenne. 


(vi.  23.)      Lateral    view   oval,   having 
transverse  bars  and  undulated  sides. 


Genus  EUNOTOGBAMMA  (Weisse).— Front  view  as  in  Anaulus  ;  lateral 
view  lunate,  with  undulated  dorsal  and  ventral  margins.  Dr.  Weisse  observes 
that  in  the  front  view  Eunotogramma  resembles  Gomphogramma,  and  in  the 
lateral  one  Eunotia  (Epithemia  ?).  In  both  instances,  however,  the  resem- 
blance is  evidently  very  superficial,  and  does  not  require  the  distinctions  to 
be  pointed  out.  The  genus  doubtless  belongs  to  the  Terpsinoea3,  and  seems 
to  differ  from  Anaulus  only  in  the  lunate  form  of  the  side  view. 

Eunotogramma  tri-  quinque-  scptem-  i  row  connecting  zone,  and  lateral,  equal, 

etnovefnloculata(Wei&se). — Lateral  view  stout,  pinna-like  septa.      Lateral  view 

divided  by  two,  four,  six,  or  eight  trans-  semilanceolate,  constricted  at  each  sep- 

verse   septa  into  three,  five,  seven,  or  turn,    and    therefore    having    as    many 

nine  loculi.    Weisse,  Bulletin  de  I'Acad.  undidations    as   loculi ;    ends  rounded, 

de  St.  Petersbom-g,  xiii.  p.  278,  t.  8.  f.  37.  (viii.  30.) 
Fossil.    Eussia.    Front  view  with  a  nar- 


FAMILY  XIII.— CH^TOCEEE^. 

Frustules  smooth  or  faintly  punctated,  simple  or  united  into  awned  fila- 
ments ;  lateral  valves,  in  the  nonfilamentous  forms,  usually  unequal,  inflated, 
lobed,  and  often  furnished  with  bristles  or  other  appendages ;  lateral  view 
oval  or  circular.  Marine,  mostly  fossil.  Until  Mr.  Brightwell  pointed  out 
their  true  affinity,  the  genera  included  in  this  group  were  distributed  amongst 
three  families.  Between  Syndendrium  and  the  Angulifereae  we  can  perceive 
no  resemblance  ;  but  the  connexion  of  Chsetoceros  with  the  Biddulphieae,  and 
the  other  genera  with  the  Melosii^ece,  is  far  more  plausible.  In  Stephano- 
pyxis,  a  true  member  of  the  latter  family,  the  valves  are  crowned  with 
bristles  or  spines,  as  in  some  Cha^tocere^e.  In  Melosireae,  however,  aU  the 
members  ought  to  be  cj-lindrical,  whereas  in  this  family  the  shape,  in  the 
lateral  view,  is  much  oftenor  oval  than  circular.  Although  it  is  not  difficult 
to  point  out  differences  between  the  Chsotoccreae  and  other  groups,  yet,  on 


or  THE  CHiET0CEREJ3.  861 

account  of  the  variety  in  theu^  forms,  we  confess  oiu'  inability,  in  the  present 
state  of  oiu-  knowledge,  to  give  a  concise  definition  which  shall  include  its 
own  members  and  exclude  all  others.  We  shall  therefore  content  oui'selves 
with  pointing  out  those  characters  which  will  enable  us  to  recognize  mth 
tolerable  certainty  those  Diatoms  which  belong  to  it.  The  filamentous  species 
diff'er  by  their  awns  so  much  from  every  other  genus  that  they  cannot  be 
mistaken.  Mr.  Brightwell,  in  his  excellent  paper  on  Chaitoceros,  regards 
this  as  the  typal  state:  he  says,  "A  careful  examination  of  most  of  the 
species  of  Cha^toceros  and  other  allied  genera,  described  by  Ehrenberg  as 
found  ui  a  fossil  state,  have  satisfied  us  that  most,  if  not  all  these,  will,  when 
found  in  a  li\ing  state,  turn  out  to  belong  to  the  singular  filamentous  and 
horned  group  which  may  for  the  present  be  comprehended  in  the  genus 
Chaetoceros."  Those  forms  also  which  have  dissimilar-shaped  valves,  espe- 
cially when  lobed  or  hirsute,  may  be  safely  placed  here ;  and  it  is  very  pro- 
bable that  some  species  with  imequal  valves,  still  retained  in  Melosireae, 
might  likewise  be  included  with  propriety. 

The  genera  themselves  are  by  no  means  firmly  established ;  for,  as  Mr. 
Brightwell  observes,  "  most  of  the  described  species  have  been  found  only  in 
a  fossil,  or  rather,  if  we  may  so  term  it,  a  deposit  state ;  and  in  this  state  it 
is  clearly  difiicult  to  form  a  correct  idea  of  either  species  or  genera,  since 
deposits  give  no  information  as  to  the  Diatoms  being  in  threads  or  solitary 
frustules."  We  shall  not  attemj)t  to  reconstruct  the  genera,  for  to  do  so 
prematurely  would  only  increase  the  difficulty  and  cause  confusion;  for 
"  much  must  yet  be  brought  to  light  before  a  satisfactory  classification  of  this 
group  can  be  eff'ected  "  (Brightwell).  Although  only  a  few  species  have  as 
yet  been  gathered  in  a  hving  state,  yet,  as  most  of  them  are  found  in  guano, 
it  is  probable  that  nearly  all  still  exist ;  and  when  their  habits  are  better 
known,  we  may  fairly  expect  to  obtain  them.  They  seem  to  inhabit  deep 
water,  as  Mr.  Norman  has  met  with  them,  more  than  once,  in  the  stomachs 
of  Ascidiae  from  such  situations. 

Genus  CH^TOCEBOS  (Ehr.).— Frustules  without  stride,  united  with  the 
adjacent  ones  by  the  interlacing  on  each  side  of  awns  proceeding  from  the 
fiaistulc  or  from  a  cingulum  between  the  frustules,  and  so  forming  a  filament. 
The  filaments  are  imperfectly  silicious  and  very  fragile.  The  awns  are  tubular, 
sometimes  spinous  or  serrated,  and  often  of  great  length,  though,  according 
to  Kiitzing,  short  in  an  early  state.  Klitzing  defines  the  genus  as  follows : — 
''  Frustules  concatenated,  equally  bivalved,  turgid,  with  two  apertures  on 
each  side,  which  at  the  earliest  period  are  very  shortly  tubular  and  the  cor- 
puscles contiguous,  afterwards  longly  awned  and  the  corpuscles  distant." 
If  the  awns  be  overlooked  or  broken  off",  the  frustules  may  be  mistaken  for 
species  of  Melosira.  No  person  who  wishes  to  study  this  beautiful  but  diffi- 
cult genus  should  fail  to  obtain  Mr.  Brightwell's  valuable  paper  on  it  in  the 
Journal  of  ISIicroscopic  Science. 

^-r,^,      -    1  ^      1    ■  ,-,■,,]  species"  CBai.  mlit.).     In  the  fi-ont  view 

*  i^r^.s^«/..,i^/.^^.r«/r?.t^,m^^rid.^a^'    j[^  frustules  are  linear,  three   or  four 

t/w  mickUe.  |  ^^^^^^  ^s  long  as  broad,  ^^Aih.  stout  awns 

Ch^toceros  Diploneis  (E.). — Frus-  |  arising  from  the  angles.  Lateral  view 
tules   in    lateral  view  panduriform,   in  i  pandiiriform,  with  rounded  ends. 


front  view  linear ;  a-wnis  smooth.  KSA 
p.  138 ;  EM.  pi.  33.  18.  f.  1  -,  Bai.  in  Amer. 
Journ.  of  Science,  xlviii.  pi.  4.  f.  19  (la- 
teral view).  =  C.  Bacillaria,  Bai.  /.  c.i.  18 
(front  view).  Bermuda  deposit.  "  ChcB- 
toceros  Diploncis  and   C.  Bacillaria   are 


2  *  Frustules  laterally  oval  or  circular ; 
atvns  spinous. 

C.  5ore«/e(BaLl.), — Frustules  quadrate ; 
a\NTis  very  long,  spinous,  arising  from 
the  inner  surface,  not  from  the  angles. 


merely  different  positions  of  the  same  '  BC.  1854,  pi,  7.  f  22,  23 ;  Bri  JjVIS.  iv 


862 


SYSTEMATIC  HISTOET  OF  THE  INFTISORIA. 


p.  107,  pi.  7.  f.  12-15 ;  Wallich,  TMS.  ^iii. 
p.  48,  pi.  2.  f.  18 ;  West,  TMS.  viii.  p.  152, 
pi.  7.  f.  13.  St.  George's  Bank,  Atlantic 
Ocean,  (vi.  25.)  "  This  species  was 
found  in  considerable  numbers  in  the 
contents  of  the  stomach  of  the  Botryo- 
dactijla  f/mndis.''  Awns  30  to  50  times 
longer  than  the  body. 

C.  Peruviamim  (Bri.). — Valves  hemi- 
spherical, with  two  very  stout,  long, 
recurved,  spinous  awns  proceeding  from 
the  centre  of  the  rounded  ends.  Br  JMS. 
iv.  p.  107,  f.  16-18.  In  Peruvian  guano. 
A  remarkable  and  very  distinct  species, 
characterized  by  the  rounded  apex  of 
the  valve.     Lateral  view  circular  ? 

3  *  Frustules  laterally  oval  or  circular ; 
awns  smooth. 

C.  Tetrachcsta  (E.). —Frustules  with 
four,  very  long,  filiform,  smooth  awns  on 
each  side.  KSA.  p.  138.  Antarctic  Sea. 
Diam.  without  the  awns,  1-1152". 

0.  DichcBta  (E.). — Frustules  with  two, 
very  long,  filiform,  smooth,  often  flexu- 
ose^  awns  on  each  side.  KSA.  p.  138. 
Antarctic  Sea.  Diam.  without  the  awns, 
1-1152"  to  1-720".  The  description  is 
too  imperfect  to  enable  us  to  distin- 
guish the  species  from  some  of  the  fol- 
lowing ones. 

C.  confervoides  (n.  sp.).  —  Frustides 
large,  quadrate  ;  awns  stout,  smooth, 
arising  a  little  beneath  the  rounded 
angles;  lateral  view  circular.  Mount's 
Bay  (stomach  of  Ascidise),  Cornwall. 
We  have  seen  only  one  concatenated 
specimen;  it  formed  a  short,  very  fra- 
gile, conferva-like  filament  of  about  12 
joints,  which  were  equal  in  length  and 
loreadth  and  in  close  apposition.  Internal 
colouring  matter  brownish,  and  collapsed 
into  a  roundish  spot  in  the  centre  of 
each  frustule. 

C.  Wighamii  (Bri.). — "  Frustules  cup- 
shaped,  with  a  band  round  the  mouth  of 
the  cup,  and  a  neck  or  bulb  proceeding 
from  the  centre ;  beset  with  minute  short 
spines  or  papillae  in  all  parts  except  the 
band;  lateral  view  oval;  awns  elon- 
gated, smooth."  Br  MJ.  iv.  p.  108,  pi.  7. 
f.  19-36.  In  brackish  water,  near  Brey- 
don,  Great  Yarmouth.  "  Boiled  in  acid, 
the  filaments  break  up,  and  the  frustules 
in  an  isolated  state,  and  detached  rings 
with  the  horns  proceeding  from  them, 
are  all  that  can  be  detected.  The  rings 
may  readily  be  distinguished  from  the 
frustules  seen  endwise,  as  they  are  open 
and  without  dots,  wnile  the  frustules 
seen  endwise  are  dotted"    (Bri.).     We 


have  seen  no  perfect  specimen  of  this 
interesting  species ;  but  as  Mr.  Bright- 
well's  fig.  12  shows  two  joints  similar 
to  other  species  of  this  genus,  we  are 
inclined  to  regard  the  Goniothecia-like 
bodies  as  internal  cells,  of  the  same 
nature  as  the  internal  cells  of  Himan- 
tidium,  Meridion,  &c.,  which  we  believe 
to  be  sporangia ;  but  whatever  their 
true  character  may  be,  we  have  scarcely 
a  doubt  that  Mr.  Brightwell  is  right  in 
supposing  Goniothecimn  crenatnm,  G.  his- 
pidum,  G.  Navicida,  and  G.  barbatum  to 
be  allied  forms  belonging  to  the  same 
genus  as  this  species,    (^t:.  24.) 

C.  ineurvum  (Bail.).  —  Frustules  in 
front  view  linear,  with  smooth,  filiform, 
recm'ved  awns  arising  from  the  angles ; 
lateral  view  oval.  Bii.  /.  c.  pi.  7.  f.  9-11. 
Fossil.  Virginia,  Peru\dan  guano.  In 
stomach  of  Ascidise,  Penzance.  Easily 
known  by  its  small  size  and  slender 
recurved  awns. 

C  furcillatum  (Bail.). — Awns  of  ad- 
joining frustules  closely  approximate 
below,  then  diverging  and  becoming 
nearly  parallel ;  lateral  ^dew  oval.  Bai. 
on  Microsc.  Forms  in  the  Sea  of  Kamt- 
schatka,  p.  3,  pi.  1.  f.  4.  Common  in  the 
Sea  of  Kamtschatka.  The  minutest  spe- 
cies in  the  genus. 

C.  didymus  (E.).  —  Frustules  longer 
than  broad,  gibbous  or  angular  on  the 
outer  margin,  and  usually  slightly  so  on 
the  inner  margin  also;  awns  smooth, 
filiform,  arising  from  the  angles.  Bri. 
/.  c.  pi.  7.  f.  3-7;  KSA.  p.  138;  EM.  t.  35  a. 
18.  f.  4.  Common  in  Peruvian  guano. 
Stomach  of  Ascidise,  Penzance.  A  va- 
riable species,  distinguished  by  its  angu- 
lar or  gibbous  margins ;  lateral  view 
oval.  Ehrenberg's  two  figures  in  the 
'Microgeologie'  difier  from  each  other, 
as  well  as  from  any  specimens  we  have 
seen.     Greatest  diameter  1-1080". 

C.  Gastridmm  (E.,  Bri.). — Frustules 
binate,  smooth,  transversely  oblong, 
truncated  at  each  end,  abruptly  dilated 
at  the  middle  of  the  ventral  surface,  not 
contiguous,  Bri.  /.  c.  pi.  7.  f.  8.  =  Goyiio- 
thecium  Gastridium,  EM.  pi.  18.  f.  91. 
Virginian  guano.  Ehrenberg  describes 
and  figures  it  with  an  external  umbo 
(gibbous),  thus  approaching  to  C.  didy- 
mus. 

C.  armatum  (\Vest). — Frustules  qua- 
drangular, forming  a  compressed  fila- 
ment ;  angles  excavated ;  from  each  an^le 
arises  a  long,  obtuse,  cui-ved  seta,  with 
several  acute  ones  at  the  base.  West, 
TMS.  viii.  p.  151,  pi.  7.  f.  12.  Abundant 
on  various  parts  of  the  coast  of  England. 


OF  THE  CH^TOCEEE^. 


863 


This  species,  in  its  living  state,  is  in- 
vested with  a  mucous  covering,  and  is 
scarcely,  if  at  all,  silicious, — a  circum- 


stance wliicli  has  caused  many  doubts 
as  to  its  diatomaceous  nature. 


Genus  ATTHETA  ("West). — Frastules  compressed,  annulate  ;  annuli  inde- 
finite ;  valve  elliptical-lanceolate,  ^dth  a  median  line  ;  angles  spinous.  The 
true  position  of  this  genus  is  doubtful ;  but,  from  examination,  it  appears  to 
approach  nearer  to  Cheetoceros  than  to  any  other  genus  excepting  Striatella, 
from  which,  however,  it  is  easily  distinguished  by  the  spinous  angles  and  ab- 
sence of  stipes. 


Attheya  decora  (West). — Annuli  12 
to  28 ;  septa  alternate ;  valve  with  me- 
dian line   and   central   nodule.     West, 


TMS.  ^-iii.  p.  152,  pi.  7.  f.  15.     CressweU 
Sands,  Drmidge  Bay.    (vni.  35.) 


Genus  BACTERIASTRUM  (Shadbolt).— Frustules  awned,  united  into  a 
jointed,  conferva-like,  cylindrical  filament;  valves  discoidal,  with  marginal 
radiating  awns.  Bacteriastrum  agrees  with  ChEetoceros  in  its  filamentous 
character  and  in  the  presence  of  awns,  but  differs  from  it  in  having  the  awns 
of  its  discoidal  valves  marginal  and  radiant.  Marine.  Stomachs  of  marine 
animals,  &c. 


Bacteriastrum  furcatum  (Sh.).  — 
Awns  smooth,  much  elongated,  forked. 
=Acthnscus  sexfurcatiis,  ERBA.  1854, 
p.  237  ;  EM.  pi.  35  b.  4.  f.  15 ;  A.  hisepte- 
nari'M,  E. ;  A.  hisoctonarius,  E.  Atlantic. 
The  awns  vary  in  number  and  in  the 
length  of  the  forked  portions,    (yr.  26.) 

B.  curvatinn  (Sh.).  —  Awns  simple, 
elongated,  smooth,  symmetrically  curved 
in  one  direction. 


B.  Wallichii  (Ealfs). — Valves  more  or 
less  cup-shaped,  with  4  to  12  smooth, 
simple,  divergent  awns.  =  Chcstoceros 
Bacteriastrum,  Wallich,  TMS.  \'iii.  p.  48, 
pi.  2.  f.  16, 17.  Atlantic.  From  Salpse. 
Size  extremely  variable,   (yr.  27.) 

B.  noclidosum  (Sh.). — Awns  siniple, 
straight,  rough. — Awns  covered  with 
small  protuberances,  like  a  knobbed 
stick. 


Genus  DICLADIA  (Ehr.). — Frustules  simple,  one-celled,  bivalved ;  valves 
unequal,  turgid,  one  mostly  simple  and  unarmed,  the  other  two-horned ; 
horns  sometimes  branched. 


DiCLADiA  Capreoliis  (E.).—rOne  valve 
with  two  stA'les  arising  from  conical 
bases,  and  usuallv  branched  at  the  end. 
EM.  pi.  35  A.  17.  f.  8  ;  Bri  JMS.  iv.  pi.  7. 
f.  53-60.  Virginia.  Common  in  guano. 
The  fi-ustide  consists  of  a  narrow-linear 
central  portion,  projecting  at  each  end, 
and  two  turgid  lateral  valves,  which 
vary  greatly  in  foi-m.  Usually  the  in- 
ferior one  is  smaller,  simple,  and  unarmed, 
but  is  often  bilobed.  The  larger  valve  is 
bilobed ;  the  lobes  manmiiform  or  conical, 
each  terminating  in  a  style  divided  at  its 


have  the  upper  valve  unarmed  or  simple. 

D.  antennata  (E.).  —  One  valve,  with 
two  simple,  setaceous,  parallel,  acute 
spines,  articulated  at  the  base,  like  an- 
tenna ;  the  other  valve  unknown.  EM. 
pi.  35  A.  21.  f.  9 ;  KSA.  p.  24.  Antarctic 
Sea.  This  and  the  next  species  were 
constituted  from  single  fragments. 

D.  bidbosa  (E.). — One  valve  with  two 
spines,  wliich  are  divergent  at  the  base, 


connivent  above,  bidbose  and  slightly 
silicate  in  the  middle  part;  the  other 
valve  unknown.  EM.  pi.  35  a.  21.  f.  10 ; 
KSA.  p.  24.     Antarctic  Sea. 

D.  clcdhrata  (E.).  —  Frustide  with  a 
rounded,  smooth,  latticed  bodv,  and  two 
unequal  frontal  horns.  EM .  pL  18.  f.  100 ; 
KSA.  p.  25.     Fossil.     Virginia. 

D.  Capra  (E.). — Smooth;  one  valve 
with  two  simple  spines,  the  other  uni- 
dentate  or  imperfectly  siib-bidentate  in 
the  middle  ;  central  portion  naiTow- 
linear.  EM.  pi.  18.  f.  99.  =  Periptera 
Capra,  KSA.  p.  26.     Fossil.    Virginia. 

D.  Cervus  (E.).  —  Smooth,  large  ; 
frontal  horns  long,  branched.  =Per?/>^e;*a 
Cervus,  KSA.  p.  26.    Fossil.     Maiyland. 

D.  Mitra  (Bai.). — Valve  having  two 
conical  horns  coalescing  below  into  a 
conical  base,  and  bearing  branched  pro- 
cesses above.  B.  in  Silliman's  Amer. 
Jom-n.  July  1856,  pi.  1.  f.  6.  Sea  of 
Kamtschatka.  Perhaps  a  state  of  D. 
Capreolus. 


864 


SYSTEMATIC  HISTOKY  OF  THE  rNFUSORIA. 


Genus  GONIOTHECIUM  (E.). — Friistules  simple,  having  a  central  con- 
striction or  furrow ;  each  end  abruptly  attenuate  and  truncate,  so  as  to  assume 
an  angular  figure.  Fossil.  Like  other  genera  in  this  family,  this  is  an  un- 
satisfactorj^  genus.  The  frustules  are  described  as  C3^1indrical ;  but  we  believe 
that  most,  if  not  all  of  them,  are  oval  when  viewed  laterally.  Mr.  Brightwell 
makes  the  following  remarks  on  eight  of  Ehrenberg's  species : — "  The  two 
largest  and  most  common  are  G,  Bogersii  and  6r.  OdonteUa  ;  and  we  think  it 
probable  these  will  tui^n  out,  if  discovered  in  a  recent  or  living  state,  to  be 
Chajtoceri.  Of  the  remaining  six  species,  we  are  led  to  conclude,  from  the 
discovery  of  the  Breydon  species,  that  two  of  them  belong  to  the  genus 
Chaetoceros,  and  are,  when  living,  filamentous.  They  are  G.  Gastridium,  of 
which  we  have  found  many  specimens  with  the  horns  perfect,  and  G.  crenatum. 
A  figure  of  a  frustule  of  this  species  is  given  in  the  '  Microgeologie '  of  Eh  ^en- 
berg,  and  it  can  scarcely  be  distinguished  from  the  frustules  of  the  Breydon 
species.  6r.  Tiispidum  and  G.  dklymimi  scarcely  appear  to  differ  fi^om  some  of 
the  smaller  frustules  of  the  Breydon  sj^ecies.  G.  Navicula  and  G.  barhatum 
are  clearly  allied  to  G.  crenatum,  or  our  Breydon  species."  The  species  differ 
in  form,  and  sometimes  do  not  correspond  "with  the  generic  character.  G. 
Gastridium  (E.)  is  proved  by  Mi\  Brightwell's  discovery  of  its  awns  to  be  a 
species  of  Chaetoceros. 


GoNiOTHECiUM  OdonteUa  (E.).  — 
Valves  binate,  smooth,  conjoined  by  a 
central  process,  and  by  their  connivent 
apices,  so  as  to  form  on  each  side  a 
large  oblong  apertm-e,  constricted  at  its 
middle ;  margin  undulate.  EM.  pi.  33. 15. 
f.  16 ;  KSA.  p.  23 ;  Bri  JMS.  v.  pi.  7. 
f.  47,  48.  Virginia.  Diam.  1-480"  to 
1-276".  Distinguished  by  its  large  size 
and  undulated  margin,  the  central  un 


projection  (connecting  process),  and 
agrees  but  badly  with  the  specific  cha- 
racter. 

G.  hispidum  (E.). — Frustules  semi- 
lunate,  hispid,  with  an  imibo  at  the 
centre  of  inner  margin.  EM.  pi.  18. 
f.  107 ;  KSA,  p.  23.     Virginia. 

G.  Navicula  (E.).  —  Frustules  small, 
smooth,  with  a  linear  produced  central 
portion  and  a  turgid  or  inflated  valve  on 


dulation  forming  an  umbo  ;  lateral  view  }  each  side.  EM.  pi.  18.  f.  105 ;  KSA.  p.  24, 


oval.    (^^.  29.) 

G.  Rogersii  (E.).  —  Valves  binate, 
smooth,  conjoined  by  a  broad  central 
process,  often  with  connivent  apices, 
forming  suborbicular  apertm'es ;  margin 
undulate.  EM.  pi.  18.  f.  92,  93  ;  KSA. 
p.  23.  Virginia.  Diam.  1-588".  Smaller 
than  G.  OdonteUa ;  "  valves  dorsally  sub- 
quadrate,  angular,  with  three  whorls, 
laterally  elliptic-oblong,  with  two  or 
three  median  circles; "  central  undulation 
unibonate.  Mr.  Brightwell's  figures  are 
more  irregular,  and  do  not  correspond  so 
accurately  with  the  definition. 

G.  ohtusum  (E.). — Valves  smooth,  in- 
flated, with  three  rounded  lobes ;  central 
or  constricted  portion  forming  a  narrow 
band.  EM.  pi.  18.  f.  95 ;  KSA.  p.  23. 
Virginia.     Diam.  1-696". 

G.  monodon  (E.).  —  Valves  binate, 
smooth,  not  contiguous,  each  linear- 
oblong,  truncate  at  each  end ;  outer  side 
uniformlv  straight,  the  inner  with  a 
median  tuberositv.  EM.  pi.  18.  f.  97 ; 
KSA.  p.  23.  Virginia,  Cahfomia.  Ehr- 
enberg's figures  represent  a  canoe-shaped 
valve,  the  outer  margin  convex,  the 
inner  with  incurved  ends  and  a  central 


Virginia.  In  this  species  the  central 
portion  projects  beyond  the  lateral  valves, 
instead  of  being  constricted. 

G.  didi/mwn  (E.).  —  Binate,  smooth, 
transversely  oblong,  obtuse ;  one  side 
emarginate  at  the  centre,  the  other  with 
two  tubercles.  EM.  pi.  18.  f.  104;  KSA. 
p.  23.  Virginia.  Diam.  1-1200".  Ehr- 
enberg's figure  shows  two  imequal  valves 
without  any  interstitial  portion,  each 
valve  with  two  rounded  lobes.  It  re- 
sembles a  hornless  state  of  Dicladia, 
except  that  it  wants  the  central  portion. 
^  G.  harhatum,  EM.  pi.  18.  f  106.  Vh- 
ginia.  Ehrenberg's  figm'e  has  a  narrow- 
linear,  longly  produced  central  portion 
and  two  unequal  turgid  valves — the 
smaller  smooth,  the  larger  conic  with  a 
tuft  of  hairs  at  its  apex. 

G.  crenatum,  EM.  pi.  39.  3.  f.  74.  Ehr- 
enberg's figure  is  semilunate,  with  a 
neck-like  truncated  cone  on  its  inner 
side.  This  species,  except  in  being 
smooth,  exactly  resembles  Mr.  Bright- 
well's figures  of  the  internal  frustules  of 
ChcBtoccros  Wighamii,  and  doubtless  be- 
longs either  to  that  or  to  an  allied  species 
of  Chretoceros.    (xv.  10.) 


OF  THE  CH.ETOCEEE.^. 


865 


Genus  OMPHALOTHECA  (Ehr.).— Characters  unknown  to  us.  Judging 
from  Ehrenberg's  figure  of  the  only  species,  it  seems  scarcely  distinct  from 
Goniothecium. 


Omphalotheca  hispida,  EM.  pi.  35  a. 
9.  f.  4*.  Ganges.  The  figure  apparently 
represents  a  frustule  in  the  process  of 
division.     The  valves  are  unequal  j  the 


smaller  one  smooth,  the  larger  some- 
what conical  and  furnished  with  scat- 
tered spines ;  connecting-zone  slightly 
produced  beyond  the  valves,  (vin.  44.) 


Genus  PERIPTERA  (Ehr.).  —  Frustules  simple,  compressed,  unequally 
bivalved ;  valves  simple,  continuous,  not  cellulose ;  one  valve  naked,  turgid, 
the  other  winged  or  horned  ;  horns  affixed  to  the  extreme  margin,  sometimes 
branched.  Approaches  very  near  to  Syndendrium  and  Dicladia.  We  think 
these  three  genera  might  be  united  with  advantage. 


Pemptera  tetracladia  (E.), — Smooth, 
almost  navicular;  one  valve  with  four 
equidistant  spines,  branched  at  the  apex, 
the  other  simple.  EM.  pi.  33.  18.  f  9. 
Fossil.  Bermuda  deposit.  Diam.  1-1440", 
including  spines  1-864".  Without  the 
spines,  it  resembles  an  Amphora.  (yi.  30.) 


P.  cJilamiclophora  (E.). — Smooth,  al- 
most navicular;  one  valve  at  the  side 
plane  and  surmounted  by  a  finel^^-nerved 
membrane,  the  other  turgid  at  the  mid- 
dle, unarmed.  EM.  pi.  18.  f.  98.  Fossil. 
Bermuda,    (viii.  25.) 


Genus  RHIZOSOLENIA  (Ehr.).  —  Filamentous;  frustules  subcylindrical, 
greatly  elongated,  silicious,  annulate ;  annuli  broadly  cuneate  ;  surface  stri- 
ated, extremities  calyptriform,  pointed  with  a  bristle.  This  genus  was  con- 
stituted by  Ehrenberg  for  the  reception  of  certain  silicious  organisms  found 
in  guano  and  various  fossil  deposits.  The  characters  assigned  by  him  to  this 
genus  are,  "  lorica  tubular,  with  one  extremity  round  and  closed,  while  the 
other  is  attenuate  and  multifid,  as  if  terminating  in  little  roots."  The  dis- 
covery of  this  remarkable  genus  in  a  living  state  has,  we  believe,  proved  that 
the  species  described  by  Ehrenberg  are  only  fragments  of  forms  similar  to 
those  we  are  about  to  describe.  Professor  Schultze  has  detected  in  R.  styli- 
formis  and  R.  ccdcar-avis  a  circulation  of  minute  granules  analogous  to  the 
currents  observed  in  the  hairs  on  the  filaments  of  Traclescantia  procuynbens. 
(Schultze,  MJ.  vii.  p.  16.) 


Rhizosolenia  styliformis  (Bri.).  — 
Frustules  from  6  to  20  times  as  long  as 
broad;  transverse  lines  (annidi)  distinct ; 
sm-face  striated,  striae  oblique,  about  40  in 
■001",  terminal  process  at  the  base  spatu- 
late  and  bifid.  Found  in  Noctilucae,  Yar- 
mouth ;  stomachs  of  Ascidians,  York- 
shire ;  Salpse,  Atlantic.  Bri  M J.  vi.  p.  94, 
pi.  5.  f.  5 ;  Norman,  ANH.  xx.  p.  158 ; 
Prof.  Schultze,  MJ.  vii.  p.  18.  pi.  2.  f.  1. 
(Am.  32.)  From  the  elongated  base  of 
the  calyptriform  process  a  stout  line  or 
rib  runs  up  on  either  side  to  nearly  the 
apex  of  the  cone ;  at  base  of  the  lines  a 
small  horn,  slightly  cm-ved  towards  the 
annuli,  is  frequently  to  be  detected. 
Self-division  has  been  observed  in  this 
and  some  of  the  following  species. 

R.  imhricata  (Bri.).  —  Frustules  4  to 
7  times  as  long  as  broad,  annuli  di- 
stinct, sm'face  of  valve  coarsely  punctate, 
terminal  process  subulate,  entire.  Found 
with   the   preceding   species.     Bri  MJ. 


p.  94,  pi.  5.  f  6.  The  direction  of  the 
transverse  lines  (annuli)  and  puncta 
give  this  species  an  imbricated  appear- 
ance. 

R.  setigera  (Bri.). — Frustules  5  to  15 
times  as  long  as  broad,  annuli  obscure, 
striae  very  faint,  terminal  bristle  fre- 
quently as  long  as  the  colom-less  frustule. 
In  Noctilucae,  Ascidians,  and  Salpae. 
Bri.  /.  c.  p.  96,  pi.  5.  f.  7.  (\^I.  33.)  This 
species  is  remarkable  for  the  great  length 
of  the  terminal  bristle  and  its  extreme 
delicacy. 

R.  alata  (Bri.). — Annuli  distinct,  striae 
faint,  terminal  process  alate,  recm'ved, 
blunt.  In  Ascidians,  Yorkshire.  Bri.  /.  c, 
p.  95,  pi.  5,  f  8.  This  curious  little  spe- 
cies is  distinguished  by  its  small  but 
conspicuous  setae  attached  to  the  base  of 
the  calyptriform  process. 

R.  calcar-avis  (Schultze).  —  Frustules 
small,  annuli  indistinct ;  tenninal  process 
slightlv  sigmoid,  the  point  resembling 
3  K 


866 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


a  bird's  claw.     Heligoland.     Scliultze^ 
MJ.  Yii.  p.21,  pl.2.  f.5. 

R.  rohnsta  (Nonnan,  MS.). — Friistiiles 
Yei'Y  broad,  sligbtly  sigmoid,  anniili  nar- 
row, calyptriform  processes  with  lines 
radiating  from  the  apices  ;  bristles  short, 
delicate,  nearly  linear.  Strife  fine,  about 
55  in  -001". "  Ascidians,  North  Sea, 
Teignmouth,  Heligoland,  Australia. 
{yjh.  42.) 

Douhtful  and  insufficiently  known  Sj^ecies. 

R,  Calyptra  (E.).  —  YalYe  (terminal 
process)  broadly  conico-campanulate, 
smooth,  its  apex  attenuated,  acute.  EM. 
pi.  35  a.  22.  f.  17.;  Bri.  I.  c.  pi.  5.  f.  2. 
Southern  Ocean,  (vn.  31.)  This  is  pro- 
bably the  terminal  process  of  R.  styli- 
f or  mis. 

R.  Campana  (E.). — Valve  large ;  apex 
conic,  longly  attenuated,  varies  as  if 
terminated  by  little  roots ;  sm-face  very 
finely  granulated.  KSA.  p.  24.  Bermuda 
deposit. 

R.  ornitlioglossa  (E.). — Valve  tubular, 
conical,  smooth,  slender,  with  a  much 
attenuated,  acute  apex,  laterally  resem- 
bling the  tongue  of  a  bird.     EM.  pi  33. 


13.  f.  21.     Antarctic  Sea. 

R.  Americana.  —  Frustules  smooth, 
hyaline,  tubular,  interrupted  by  septa, 
one  end  roimd,  the  other  stvliform, 
simple  or  branched.  EM.  pi.  18.  f.  98. 
Fossil.  America.  This  seems  a  species 
ver}^  variable  in  size  and  form.  The 
outline,  however,  of  the  rostrate  valve 
bears  some  resemblance  to  a  bottle,  with 
the  neck  or  beak  simple  or  branched. 

a.  hebetata  (Bai.). — Valve  cah-ptri- 
form,  punctate,  with  a  smooth,  cylin- 
drical base ;  apex  expanded,  compressed. 
B.  in  Silliman's  Amer.  Journ.  July  1856, 
p.  5,  pi.  1.  f.  18, 19.  Seas  of  Kamtschatka 
and  Ochotsk.  The  expanded  apex  re- 
sembles in  outline  the  iiame  of  a  candle. 
The  punctate  conical  portions  are  most 
frequently  seen ;  but  specimens  vdih  the 
cylindrical  base  are  occasionally  found, 
Bail. 

R.  Pileolus  (E.).  — Valve  small,  short, 
as  broad  as  long ;  central  portion  linear, 
produced ;  one  valve  resembling  an  umbo, 
the  other  conical,  branched  at  apex.  EM. 
pi.  18.  f.  103.  Virginia.  Diam.  1-1320". 
Has  the  habit  of  Hicladia  or  Gonio- 
thecium. 


Genus  SYRINGIDIUM  (Ehr.). — Frustules  simple,  cylindiical ;  valves  un- 
equal, dissimilar,  distended  by  a  turgid  middle  ring.     Maritime. 


SYRiNarDiuM  hicorne  (E.). — Smooth, 
elongated,  with  three  constrictions,  one 
end  pointed,  the  other  subglobose,  two- 
spined.  EM.  pi.  35  a.  9.  f.  11*.  Ganges. 
Africa,    (vm.  20.) 

S.Palaomon  (E.). — Resembles  the  pre- 
ceding species,  but  is  gTanulated.  EM. 
pi.  34.  8.  f.  15.     Japan. 

S.  Americamim  (Bai.  MS. ;  yh.  34, 
from  a  drawing  by  Professor  Bailey). — 


Common  in  Para  River,  and  sparingly 
in  the  soundings  off  the  mouth  of  the 
Amazon,  South  America.  Frustules 
very  minute,  pimctated ;  central  portion 
quadrangular ;  valves  imequal,  one  with 
a  quadrate  base,  suddenly  contracted  and 
then  tapering  into  a  pja'amidal  spine 
terminated  by  a  mucro ;  the  other  valve 
subglobose,  with  two  short  basal  pro- 
cesses, each  ending  in  a  spine. 


Genus  SYNDENDRIUM  (Ehr.). — Frastules  simple,. bivalved,  subquadi'an- 
g-ular,  one-celled,  without  lunbilicus  in  the  middle ;  valves  unequal,  rather 
turgid,  one  smooth,  the  other  furnished  with  many  styles  branched  at  the 
apex;  margin  naked.  Syndendrium  differs  from  Dicladia  only  in  ha^ang 
several  instead  of  two  spines  on  one  of  its  valves ;  yet  Kiitzing  has  placed 
them  in  different  families. 


Syndendriuim  Diadcma  (E.). — Frus- 
tules lanceolate,  with  several  spines  in 
the  centre  of  one  valve,  forked  or  peni- 
cillate  (split  up  like  a  brush),  their  length 
equalling  the  thickness  of  the  frustule. 
EM.  pi.  35  A.  18.  f.  13 ;  Bri  MJ.  iv.  p.  7. 
f.  49-52  ;    Donkin,  TMS.  vi.   p.  1.     In 


Peru^dan  guano ;  Sea  of  Kamtschatka ; 
stomach  of  Aseidia,  Penzance.  Diam. 
1-1152".  The  central  portion  is  naiTOW 
linear,  projecting  at  each  end,  the  lateral 
valves  convex,  one  smooth,  the  other 
with  branched  spines ;  lateral  view  oval. 


Genus  HERCOTHECA  (Ehr.).  —  Frustule  simple,  turgid,  of  two  unequal 
valves ;  membrane  of  valves  continuous,  not  cellulose,  generally  veined  be- 
neath the  free  setse,  which  are  permanent  and  assume  the  place  of  an  integ-u- 


OF  THE  COCCONEIDEiE. 


86\ 


ment.  Hence  the  coipiisclcs  on  the  npper,  contiguous  margin  of  each  valve 
appear  as  if  crowned  and  enveloped  (as  it  were,  shielded)  by  the  opposite  setae 
or  membranes. 


Hercotheca  mammillai'is  (E.).  — 
Valves  smooth,  with  the  centre  of  the 
base  fringed  romid  (fortified)  v.dth  about 
twenty  simple,  opposite   setae,  inserted 


on  the  margin  itself,  and  extending  be- 
yond the  mammillfe.  EM.  pi.  33.  18, 
f.  7.     Fossil.     Bemiuda.     (vn.  35.) 


FAMILY  XIY.— COCCONEIDE^. 

Frustules  elliptic,  rarely  bent,  adnate  by  an  inferior  lateral  surface,  having 
a  median  longitudinal  line  and  central  nodule.  "  The  lateral  surfaces  prevail 
so  much  that  the  central  portion  is  reduced  to  a  simple  margin,  and  conse- 
quently it  is  difficult  to  obtain  a  front  view"  (Meneg.).  Campy lochscus  and 
Ehaphoneis,  the  only  members  of  another  family  with  which  any  of  the 
Cocconeideae  are  likely  to  be  confounded,  are  distinguished  by  the  absence  of 
a  central  nodule.  Those  species  of  jS"avicula  which  are  eUiptic  in  the  lateral 
view  somewhat  resemble  species  of  Cocconeis ;  but  they  are  never  adnate, 
and  in  them  the  central  nodule  is  equally  developed  in  both  valves. 

Genus  COCCONEIS  (Ehr.).  —  Characters,  those  of  the  family.  Fnistules 
depressed  or  somewhat  hemispherical ;  the  central  nodule  is  wanting  or 
obscure  in  the  inferior  lateral  surface,  and  sometimes  there  is  a  transverse 
as  well  as  a  longitudinal  line.  "  The  general  form  of  Cocconeis  is  that  of  a 
disc  of  an  ellipsoidal  figure,  with  sm^faces  more  or  less  exactly  parallel,  plane, 
or  shghtly  curved.  .  .  .  The  characters  by  which  the  species  of  this  most 
elegant  genus  are  distinguished  one  from  another  are  still  very  slight " 
(Meneg.).  The  frustules  in  this  genus  are  frequently  fiu^nished  with  an 
additional  membranous  covering,  which  also  forms  a  border  to  them,  and  has 
been  admitted  into  the  specific  definitions ;  but  we  believe  this  envelope 
generally,  if  not  invariably,  belongs  to  the  immature  state,  and  afterwards 
disappears  more  or  less  completely ;  and  on  this  account  we  consider  it  an. 
unsafe  differential  character.  The  descriptions  apply  to  the  lateral  view, 
unless  otherwise  stated. 

j  smooth ;  front  view  oblong,  rectangular. 
j  KB.  t.  4.   £  16.      Coast  of  Normandy. 

1-1320".     Nidulating  in  mucus. 
I       C.    elongata    (E.).  —  Small,    smooth, 
i  oblono'-elliptic,  plane.    EM.  pi.  5.  3.  £  26. 
I  America,  Em-ope,  Africa,  China.  Smaller 

than  C.  Placentula,  but  may  be  a  variety 

of  that  species. 

C.  Crux  (E.).  —  Smooth,  elliptic,  thin, 

with  a  transverse  linear  umbilicus.  KSA. 

p.  53.     Western  Asia.     Diam.  1632". 
C.dkq)hana(S.). — '^  Elliptical,  scarcely 

silicious,    diaphanous ;     striss    obscm-e. 

Length  -0012"  to  -0018"."   SBD.  i.  p.  22, 

pi.  30.  £  254.     "  /3,  nodule  dilated  into  a 

stam'os."     Sidmouth,  Jersey. 

C.  Pediculus   (E.).  —  Small,    elliptic, 

somewhat  angular,  slightly  curved ;  disc 

with  very  fine,  dotted  longitudinal  lines. 

SBD.  i.   p.  21,  pi.  3.   £  31.      Aquatic. 

Common.     ^.  salina  (K.),  narrower  near 

the  margin,  furnished  with  very  delicate 
3k2 


*  Disc  smooth  or  icith  longitudinal  lines. 

Cocconeis  longa  (E.). — Very  minute, 
linear-oblong,  with  rounded  ends,  smooth, 
except  a  median  line  and  nodule.  EM. 
pi.  5.  1.  £,25.     Aquatic.     Iceland. 

Q.pumila(K.). — Very  minute,  curved ; 
lateral  ^dew  oblong-elliptic,  smooth, 
without  lines  or  accessory  border.  KB. 
pi.  5.  9.  £  2.  Aquatic.  Emope.  Length 
1-1560".  Eabenhorst  describes  it  as 
destitute  of  median  Hne  and  nodule. 

C.  ivjgnKBci  (K.).  —  Very  minute, 
smooth,  eUiptic,  girt  by  a  crenidate  ge- 
latinous border.  KB.  t!^  5.  6.  £  4.  Baltic 
Sea,  on  Ceramium.     1-2640". 

C.  molesta  (K.).  —  Minute,  smooth, 
elliptic-oblong,  without  an  accessory 
border,  densely  aggregated.  KB.  pi.  5. 
7.  £1,2.  Marine.  Venice.  1-1800"  to 
1-1680". 

C.    nidulans   (K.).  —  Elliptic-oblong, 


868 


SYSTEMATIC  HISTOKY  OF  THE  INFUSORIA. 


transverse  striae  :  Saxony,  y.  minor  (K.). 
In  tliis  species  the  strise  are  visible  only 
when  highly  magnified.  It  is  best  di- 
stinguished by  its  slightly  angular  or 
rhomboid  form — a  character  not  noticed 
by  Ehrenberg,  who  gives  in  the  '  Micro- 
geologie '  only  one  figure,  and  five  habi- 
tats.    Diam.  1-2200"  to  1-960". 

C.  depressa  (K.). — Minute,  much  de- 
pressed, plane,  elliptic,  furnished  near 
the  margin  with  pimctated  striae.  KB. 
pi.  5.  f.  8.  2.  Aquatic.  Eiu'ope.  Accord- 
ing to  Rabenhorst,  it  resembles  a  small 
and  flat  state  of  the  var.  salina  of  the 
preceding  species.     Diam.  1-1800". 

C.  Placentula  (E.),  —  Plane,  elliptic, 
\\\\h.  faint,  dotted  longitudinal  lines. 
SBD.  i.  p.  21,  pi.  3.  f.  32.  (\^i.  36.) 
Aquatic.  Common.  1-1440".  Ehren- 
berg, in  his  '  Microgeolo^ie,'  gives  many 
figm-es  and  upwards  of  sixty  habitats  for 
this  species.  His  definition  differs  from 
that  of  Professor  Smith,  and  is  as  fol- 
lows : — "  Plane,  elliptic,  with  an  abrupt 
margin;  within  and  without  smooth." 
Having  seen  no  authentic  specimens  of 
C.  Placentula  and  C.  Pedicidus,  we  have 
adopted  Professor  Smith's  views,  but  do 
not  implicitly  rely  on  them ;  for  not  only 
do  Ehrenberg  and  Smith  differ  in  their 
descriptions,  but  whilst  the  latter  states 
that  both  species  occm-  in  the  Lough 
Moume  deposit,  the  former  has  excluded 
them  from  his  lists  of  species  found 
in  it. 

C.prcetexta  (E.). — Small,  elliptic,  with 
six  longitudinal  lines  on  each  side  of  the 
centre,  and  a  dilated,  smooth,  areolar 
margin.  EA.  pi.  3.  3.  f.  11.  Japan, 
India,  Africa,  America. 

C.pimctata  (E.). — Small,  elliptic,  with 
eight  punctated  longitudinal  lines  on 
each  side  of  the  median  line.  KB.  p.  72, 
pi.  29.  f.  30.     Australia,  America. 

C.  eughjpta,  EM.  pi.  34.  6  a.  f.  2.  Flo- 
rida. Ehrenberg' s  figure  represents  a 
smaU  elliptic  form,  with  broadly  rounded 
ends,  and  a  median  line  and  nodule, 
having  on  each  side  parallel,  distinctly 
dotted  longitudinal  lines. 

C.  striolata  (Rab.).  —  Small,  narrow- 
elliptic,  with  dense,  faint  longitudinal 
striae  on  each  side  of  the  median  line. 
Rab  D.  p.  28,  pi.  10.  f.  8.  Aquatic. 
Salzburg. 

C.  ohlonga  (K.). — Oblong-eUiptic,  with 
somewhat  acute  apices  and  longitudinal 
lines.  KB.  p.  72,  pi.  5.  8.  f.  7.  North 
Sea  and  Indian  Ocean.     1-320". 

C.  limhata  (E.). — Large,  elliptic,  with 
broadly  rounded  ends,  very  fine  longi- 
tudinal lines,  and  a  subentire  gelatinous 


border.  EM.  pi.  14.  f.  42.  Adriatic  and 
Mediterranean  Seas,  1-576".  Raben- 
horst  describes  this  species  as  like  C. 
Placentida  with  a  distinctly  developed 
border-like  membrane. 

C.  oceanica  (E.).  —  Large,  roimdish- 
elliptic,  with  numerous  delicately  punc- 
tated, somewhat  converging  longitudi- 
nal lines ;  dorsmn  convex.  KSA.  p.  52. 
Europe,  America,    (xu.  42.) 

C.  concentrica  (E.). — Large,  broadly 
elliptic,  with  broadly  rounded  ends  and 
concentric  longitudinal  lines.  KB.  p.  72, 
pi.  28.  f.  15.     Mexico. 

C.  undulata  (E.).  —  Elliptic ;  dorsum 
slightly  convex ;  exterior  furrowed,  with 
undulated  concentric  lines.  KB.  p.  72, 
pi.  5.  f.  11.  Baltic,  Asia,  Afi-ica.  1-432". 
Not  transversely  striated. 

C.  lineata,  EM.  numerous  figures  and 
habitats.  Australia,  Asia,  Africa,  Eu- 
rope. We  have  seen  no  description  of 
this  species ;  but,  according  to  Ehren- 
berg's  figures,  it  seems  to  differ  from  C. 
undulata  in  the  nonconvergence  of  its 
longitudinal  striae.  Apparently  a  very 
common  species,  as  Ehrenberg  gives 
upwards  of  fifty  habitats. 

C.  fasciata  (E.). — Large,  elliptic ;  disc 
with  dotted  longitudinal  lines  on  each 
side  the  median  line,  intersected  by  a 
transverse  median  smooth  band.  £B. 
p.  72,  pi.  28.  f.  14.     Aquatic.     Peru. 

C.  gemmata,  EM.  pi.  37.  2.  f.  1.  Ore- 
gon, vEgina.  Ehrenberg's  figm-e  is  large, 
broadly  elliptic,  wdth  rounded  ends  and 
a  smooth  linear  median  line,  having 
on  each  side  five  or  six  parallel,  lon- 
gitudinal, moniliform  series  of  large 
gTanules. 

C.  aggregata  (K.).  —  Oblong-eUiptic, 
girt  with  a  broadish  lacerated,  crenidate 
limb ;  disc  having  near  the  margin  finely 
dotted  rays,  and  in  the  middle  punc- 
tated longitudinal  lines.  IvB.  p.  72, 
pi.  5.  8.  f.  5.  Baltic  and  North  Seas. 
1-1440". 

C.  marginata  (K.).  —  Elliptic,  wath 
radiatingly  pimctated  margin  and  dis- 
coid longitudinal  lines.  KB.  p.  72,  pi.  5. 
6.  f.  1.     Marine.     Europe.     1-840". 

C.  dirupta  (Greg.). — Broadly  elliptic 
or  suborbicular,  wjth  a  smooth  median 
line,  having  on  each  side  wavy  longi- 
tudinal and  faint  transverse  striae.  GDC. 
p.  19,  pi.  1.  f.  25.  Scotland.  The  lon- 
gitudinal striae  are  most  evident  in  the 
centre,  and  the  transverse,  which  are 
somewhat  radiant,  near  the  margin. 
LTnder  a  low  power  the  nodule  appears 
dilated  into  a  stauros.  Professor  Gregory 
states  that  it  differs  in  its  brown  colour 


OF  THE  COCCONEIDE-S. 


869 


and  conspicuous  strise  from  C.  diaphana, 
the  only  allied  species. 

2  *  Disc  with  radiant  or  transverse 
strice. 

C.  striata  (E.).  —  Elliptic-oblong,  of 
medium  size,  witli  parallel  or  somewhat 
converging  transverse  striae.  EM.  many 
figures.  Aquatic.  Apparently  common, 
as  Ehrenberg  gives  upwards  of  forty 
habitats  in  different  parts  of  the  world. 
Lough  Mom-ne  deposit. 

C.  horealis  (E,).  —  Elongated-elliptic 
or  oblong  with  rounded  ends  and  parallel 
or  converging  transverse  striae.  EM. 
several  figures.  Ehrenberg  gives  about 
thirty  habitats  in  Asia,  Africa,  &c.  Ex- 
cept in  its  more  elongated  frustule,  it 
scarcely  differs  from  C.  striata. 

C.  transversalis  (Greg.). — Small,  nar- 
now-elliptic,  with  fine,  parallel,  dotted 
transverse  striae  reaching  the  median 
line.  Greg  MJ.  iii.  pi.  4.  f.  7.  (vii.  37.) 
Scotland. 

C.  atmospherica,  EM.  pi.  39.  3.  f.  9. 
Scirocco  dust.  Ehrenberg's  figure  is 
large,  elliptic,  with  median  line  and 
nodule  and  dotted  parallel  transverse 
striae. 

C.  hijperhorea  (E.).  —  Large,  elliptic, 
finely  punctato-striate  ;  striae  in  the 
middle  margin  of  the  disc,  18  in  1-1200", 
continued  to  the  median  furrow  as 
puncta;  the  fine  triple  line  of  furrow 
with  a  single,  distinct,  transversely  ob- 
long median  umbilicus.  ERBA.  x^iii. 
p.  526 ;  EM.  pi.  35  a.  23.  f.  4.  Assistance 
Bay.  Nearly  resembles  C.  Scutum  of 
New  HoUand.  Breadth  rather  more 
than  half  the  length. 

C.  nigricans  (K.).  —  Narrow-elliptic, 
densely  aggregated,  girt  by  an  entire, 
rather  broad,  brownish-black  border; 
transverse  striae,  13  or  14  in  1-1200". 
KB.  p.  72,  pi.  5.  8.  f.  8.  Trieste.  /3.  de- 
nudata,  border  obsolete.  KB.  t.  5.  8. 
f.  10.     1-1320"  to  1-1200". 

C.  consociata  (K.).  —  Broadly  elliptic, 
with  a  hyaline,  longitudinal  median 
line ;  disc  with  13  punctated,  almost 
radiant  striae  on  each  side.  KB.  pi.  5.  8. 
f.6.     Maiine.     Baltic.     1-1320". 

C.  Pinnularia  (K.).  —  Roundish-ellip- 
tic, transversely  striated,  except  a  smooth, 
crenated,  longitudinal  median  fascia. 
KSA.   p.  62;    KB.   p.  73,   pi.  5.   f.  34. 

=  Cocconeis ?,  BAJ.  xlii.  t.  2.  f.  34. 

America.  This  very  doubtfid  species  was 
constituted  by  Kiitzing  from  Professor 
Bailey's  figure. 

C.  Persica  (Rab.).  —  Large,  elliptic, 
with  a  longitudinal  median  line,  dilated 


I  at  centre  and  ends,  and  having  23  gra- 
nulated transverse  striae  on  each  side. 
Rab  D.  p.  27,  pi.  3.  f.  5.     Persia. 

C.  major  (Greg.).  —  Very  large,  thin, 
flat,  broadly  elliptic  or  suborbicidar, 
with  numerous  delicate  transverse  striae  ; 
median  line  with  central  and  terminal 
nodules.  GDC.  p.  21,  pi.  1.  f.  28.  Scot- 
land. Hyaline,  without  distinct  border ; 
striae  about  54  in  -001",  somewhat  con- 
centric with  extremities. 

C.  Scutellum  (E.).  —  Elliptic,  with 
finely  punctated  ti-ansverse  striae  con- 
centric with  its  exti'emities ;  stiiae  18  in 
•001".  EI.  p.  194,  pi.  14.  f.  8;  SBD.  i. 
p.  22,  pi.  3.  f.  34.  Marine.  According  to 
Ehrenberg,  foimd  in  every  quarter  of  the 
globe ;  yet  he  gives  fewer  habitats  for 
this  than  for  some  other  species,  (ix.  162, 
163.)  j3,  nodule  dilated  into  a  stauros  : 
S.  /.  c.  pi.  30.  f.  34.  y,  disc  with  stauros, 
veiy  fine  striae,  and  two  lateral  semioval 
markings  :  Ro  M J.  vi.  pi.  3.  f.  9.  Dorsum 
convex.  1-1150".  The  species  thus  cha- 
racterized is  veiy  variable  in  size  and 
form  and  in  the  size  of  its  puncta.  Per- 
haps the  varieties  should  be  constituted 
distinct  species. 

C.  Arraniensis  (Grev.). — Valve  ovate ; 
striae  concentric  wdth  the  extremities, 
faint,  monilifoi-m,  contiguous,  reaching 
the  median  line ;  striae  30  in  -001".  Grev 
JMS.  vii.  p.  80,  pi.  6.  f.  2. 

C.  speciosa  (Greg.). — Small,  rhomboid- 
elliptic,  with  12  distinctly  gTanulated 
transverse  striae  in  -001",  and  somewhat 
concentric  with  extremities.  Greg  MJ. 
iii.  pi.  4.  f.  8.  Scotland.  So  nearly  allied 
to  Cf.  Scutellum,  that,  although  its  more 
distant  striae  are  formed  of  fewer  and 
larger  gi-anules,  we  must  doubt  whether 
these  species  be  really  distinct. 

C.  Mediferranea  (K.).  —  Elliptic  or 
elliptic-oblong,  with  distinct  puncta, 
regidarly  arranged  so  as  to  form  both 
transverse  and  longitudinal  series.  KB. 
p.  73,  pi.  5.  6.  f.  8.  Mediten-anean  Sea. 
Rather  large;  dorsum  slightly  convex. 
1-840"  to  1-552".  In  Kiitzing's  figures 
the  striae  appear  somewhat  concentric 
with  extremities ;  and  we  doubt  whether 
it  be  distinct  from  C.  Scutellum. 

C.  Peruviaiia  (K.). — Elliptic,  regularly 
punctate,  the  larger  puncta  quadrate, 
more  distant.  KB.  p.  73,  pi.  5.  6.  f.  7. 
Marine.  Western  shores  of  America. 
1-840".  Kiitzing's  figure  seems  very 
similar  to  C.  3Iediterranea. 

C.  Adriatica  (K.).  —  Large,  elliptic ; 
striae  granulated,  transverse  on  the  disc, 
radiatmg  on  the  margin.  KB.  p.  73, 
pi.  5.  6.  f.  2  &  9.     Adriatic  and  Medi- 


fO 


SYSTEilATIC  HISTORY  OF  THE  INFTJSOJllA. 


terranean  seas.  1-696"  to  1-480".  Dor- 
sum convex.  The  striae  in  Kiitzing's 
figm-es  are  concentric  witli  the  extremi- 
ties ;  and  this  species  seems  to  differ  from 
C.  Scutellum  in  its  more  distinct  border. 

C.  distans  (Greg.).  —  Elliptic,  with 
somewhat  attenuated  ends,  a  delicate 
median  line  and  transverse  series  of 
equal,  rather  distant  granules.  GL)C. 
p.  18,  pi.  1.  f.  23.  (vii.  38.)  Scotland. 
This  species  agrees  vv'ith  C.  Scutellum  in 
its  granulated  striae,  somewhat  concen- 
tric with  extremities,  hut  it  appears  to 
us  distinct.  The  striae  are  fewer,  the 
granules  far  more  conspicuous,  and,  ac- 
cording to  Professor  Gregory,  equal,  and 
situated  on  white,  hyaline,  faint  bars, — 
characters  absent  in  C.  Scutellum. 

C. lamprosticta (Greg.). — Large,  rhom- 
boid or  broadly  lanceolate  with  obtuse 
apices,  a  median  line,  and  transverse 
series  of  rather  distant  conspicuous 
granules.  Greg  TMS.  v.  pi.  1.  f.  28. 
Scotland.  This  species  agrees  with  C. 
distans  in  having  conspicuous  transverse 
series  of  granules  somewhat  concentric 
wdth  extremities,  but  differs  in  its  elon- 
gated form. 

C.  splendida  (Greg.). — Large,  elliptic, 
with  conspicuous,  moniliform  trans- 
verse striae,  a  broad  margin,  and  a  me- 
dian line  dilated  at  centre  and  ends. 
GDC.  p.  21,  pi.  1.  f.  29.  Scotland.  Stride 
somewhat  concentric  with  extremities, 
their  granules  near  the  margin  being 
closer,  and  thus  forming  a  continuous 
rim,  with  the  median  line  terminating 
at  its  inner  edge.  Eemarkable  for  its 
large  size.  Length  about  -0044" ;  breadth 
•0039". 

C.  Regina  (Johnston).  — Valve  ovate ; 
striae  20  in  -001",  concentric  around  the 
extremities,  distinctly  granular  on  either 
side  the  median  line,  in  their  course  out- 
wards faintly  moniliform,  more  conspi- 
cuously so  and  forming  a  sort  of  border 
near  the  margin.  Johnston,  JjMS.  viii. 
p.  13,  pi.  17.  f.  1.     Elide  guano. 

C.  2^^(fictatiss{ma  (Grev.).  —  Elliptic, 
densely  areolato-punctate ;  striae  monili- 
form, concentric  with  extremities ;  me- 
dian line  dilated  at  ends;  rim  simply 
striated.  Grev  MJ.  v.  p.  8,  pi.  3.  f.  1. 
Marine.  Trinidad.  Striie  20  in  -001". 
Dr.  Greville  says  it  differs  from  C.  Mor- 
risii  in  its  finer,  closer,  and  more  mi- 
nutely punctated  strite. 

C.  crehrestriata  (Grev.).  —  Elliptic- 
oljlong,  delicately,  closel}-,  and  uniformly 
pimctato-striate ;  stria?  concentric  with 
extremities ;  median  line  straight,  simple. 
Grev  M J.  v.  p.  9,  pi.  3.  f.  2.     Trinidad. 


Length  -0022"  to  -0028";  breadth  -0012" 
to  -0014" ;  stri^  30  in  -001".  The  figure 
shows  the  ends  of  the  valve  more  atte- 
nuated than  usual  in  this  genus. 

C.  Gret'illii  {S.). — Elliptic,  with  trans- 
verse costae ;  striae  monilifonn,  15  in 
•001".  ^  SBD.  i.  p.  22,  pi.  3.  f.  35.  Eng- 
land, South  Africa. 

C.  regalis  (Grev.). — Valve  orbicular  j 
striae  moniliform,  5  in  -001",  occupying 
about  a  third  of  the  diameter,  externally 
continued  by  large  distant  granules, 
forming  three  or  fom*  concentric  rows. 
Grev  JMS.  vii.  p.  179,  pi.  7.  f.  1.  Cali- 
fornian  and  Algoa  Bay  guanos.  Striae 
coarse,  outer  granules  large  and  promi- 
nent, continued  round  the  whole  valve, 
but  smaller  near  the  extremities.  Median 
line  abbreviated. 

Cinnnata  (Greg.). — Valve  oval ;  striae 
concentric  with  the  extremities,  large, 
moniliform,  not  reaching  the  median 
line,  but  leaving  a  narrow  elliptical  blank 
space ;  median  line  distinct.  Grev  JMS. 
vii.  p.  79,  pi.  6,  f.  1.     Lamlash  Bay. 

C.  Par  mulct  (B.). — Broadly  elliptic, 
with  a  median  longitudinal  line,  having 
on  each  side  10  to  12  large,  irregular 
transverse  costae  (or  sulci)  ;  surface  with 
transverse  granulated  striae.  Bail.  Proc. 
Phil.  Acad.  1853.     Tahiti. 

C.  sulcata  (B.).  —  Broadly  elliptic  or 
suborbicular,  with  30  to  40  transverse 
arcuate  sulci.    Bail.  I.  c.    Puget's  Sound. 

C.  inconspicua  (Grev.). — Suborbicular, 
with  a  broad,  rather  strongly  striated 
border ;  disc  diaphanous,  strite  iaiut,  con- 
centric with  extremities,  becoming  ob- 
scure in  the  centre.  Grev  MJ.  \.  p.  9, 
pi.  3.  f.  3.  Trinidad.  Diam.  •OOU"  ; 
striae  22  in  -001".  Dr.  Greville's  figure 
shows  the  strias  radiating  rather  than 
concentric  with  the  extremities,  and 
leaving  a  blank  median  space  bisected 
by  the  median  line  and  nodule. 

C.  ornata  (Greg.).  —  Elliptic,  with  a 
strongly  striated  rim ;  disc  with  a  lan- 
ceolate median  blank  space,  bisected  by 
a  faint  median  line  and  large  nodule; 
striae  somewhat  radiant.  GDC.  p.  19, 
pi.  1.  f.  24.     Scotland. 

C.  Finnica  (E.).  —  Ovate  -  oblong, 
slightly  convex,  smooth  externally,  but 
striated  within.  /3  larger,  elliptic,  three 
or  four  times  longer  than  broad.  EM. 
many  figui*es.  Ehrenberg  gives  about 
thii'ty  habitats  in  Australia,  Asia,  Ame- 
rica, and  Europe,  (xii.  41.)  1-570"  to 
1-360".  Ehrenberg's  figm-es  do  not  agree 
with  his  description.  They  are  elliptic 
with  finely-dotted  transverse  striir,  and 
a   ])lank,   generally  lanceolate  longitu- 


OF  THE  COCCONEIDE^. 


871 


dinal  fascia,  bisected  by  median  line  and 
nodule. 

C.  Brimdusiaca  (Rab.). — Very  large, 
-w-ith  very  convex  dorsimi ;  disc  elliptic- 
oblong,  witli  from  22  to  24  someT\^liat 
diverging,  transverse,  gTanulated  costte, 
and  an  oblong  central  blank  space  bi- 
sected bv  a  linear  median  line.  Eab  D. 
p.  28,  t.  3.  f.  16. 

C.  margaritifera  (E.). — Broadly  ovate, 
with  subacute  ends  and  transverse  gTa- 
nulated striae  like  rows  of  pearls.  Marine. 
Bosphorus,  South  Africa.  It  is  closely 
allied  to  C.  Americana,  but  is  rather 
larger  and  not  curved. 

C.  nitida  (Greg.). — Broadly  oval,  with 
suddenly  contracted,  subacute,  short, 
point-like  apices,  transverse  rows  of 
very  large  pearl-like  granides,  and  a 
narrow-lanceolate  blank  median  space. 
GDC.  p.  20,  pi.  1.  f.  26.  Scotland.  The 
granules  are  so  aiTanged  as  to  form  both 
longitudinal  and  transverse  series.  With- 
out the  central  nodule,  which  we  have 
not  detected,  this  species  agrees  with 
Ehaphoneis. 

3  *  Lateral  vieiv  rhomboid. 

C.  rhombea  (E.).  —  Rhomboid,  with 
about  three  longitudinal  lines  on  each 
side  the  median  suture.  EM.  pi.  35  a.  7. 
f.  2.  Aquatic.  Niagara.  1-1200".  Re- 
sembles C.  Americana.  With  the  excep- 
tion of  the  median  line  and  nodule, 
Ehrenberg's  figure  has  no  markings. 

C.  Americana  (E.). — Small,  rhomboid, 
with  somewhat  produced  obtuse  apices 
and  faint  (sometimes  obsolete)  dotted 
transverse  striae.  KSA.  p.  53.  C.  Mexi- 
cana,  EA.  t.  3.  5.  f.  7.   Mexico,  (xii.  48.) 

4  *  Strice  decussating. 

C.  decussata  (E.).  —  Large,  broadly 
elliptic,  rough  with  decussating  series  of 
apiculi.  KB.  p.  73,  pi.  28.  f.  17.  Cuba, 
India. 

C.  rhomhifera  (B.).  —  Broadly  elliptic 
or  suborbicular,  with  a  sigmoid,  ob- 
liquely longitudinal  median  line,  run- 
ning through  a  smooth  space,  attenuated 
at  the  ends  and  enlarged  at  the  nodule 
into  a  rhomboid  figm-e;  sm-face  decus- 
sately and  transversely  pimctate.  Bail. 
in  Proc.  Acad.  Philad.  1853.  Puget's 
Sound. 

5*  StriiB  transverse,  separated  into  two 
series  on  each  side  the  median  line  by  a 
blank  longitudinal  fascia. 

C .  pseudo-inarginata  (Greg. ) . — Large, 
broadly  elliptical,  with  median  line  and 
nodides  having-  on  each  side  fine  trans- 


verse striae,  intermpted  and  separated 
into  two  series  by  a  lonsitudinal  blank 
fascia.  GDC.  p.  20,  pi.  1.  f.  27.  (vn.  39.) 
Scotland.  Thin,  transparent,  the  ends 
less  rounded  than  in  many  species,  me- 
dian line  not  reaching  the  extremities, 
and  enclosed  in  the  lanceolate  space 
formed  by  the  convergence  of  the  two 
lateral  fasciae. 

C.  tceniata,  EM.  pi.  6.  2.  f.  12.  Fossil. 
Morea.  We  have  seen  no  description  of 
this  species.  The  figure  represents  it  as 
elliptic,  having  its  transverse  striae  di- 
vided into  two  series  on  each  side  the 
median  line  and  nodule  by  a  longitu- 
dinal blank  fascia,  as  in  some  species  of 
Na^dcida. 

6  *  Disc  icith  longitudinal  concentric  lines 
interrupted  by  radiating  costce. 

C.  radiata  (Greg.).  —  Elliptic,  with 
rounded  ends,  about  8  concentric  lines 
inteiTupted  by  nimierous  (18)  strong 
rays  proceeding  from  the  umbilical 
nodule.  Greg  TMS.  v.  pi.  1.  f.  26. 
Scotland. 

C.  costata  (Greg.). — Valve  oval,  rather 
broad,  median  line  conspicuous,  nodule 
obsolete,  marked  with  strong  entire 
costse  reaching  from  the  median  line  to 
the  margin;  spaces  between  the  costas 
striate ;  striae  at  right  angles  to  the 
costae.  Glenshira  sand.  Greg  TMS.  v, 
p.  68,  pi.  1.  f.  27. 

7*  Median  line  and  nodule  excentric. 

C.  ?  excentrica  (Donkin). — Suborbicu- 
lar, divided  unequally  by  the  median 
line,  which  does  not  reach  the  margin, 
and  fm'nished  with  fine,  dotted,  trans- 
verse, converging  striae.  Donkin,  TMS. 
vi.  pL3.  f.  11.  Marine,  (vn.  40.)  North- 
umberland. One  of  Dr.  Donldn's  in- 
teresting discoveries,  remarkable  for  the 
excentric  position  of  its  median  line  and 
umbilical  nodule,  and  probably  the  type 
of  a  new  genus.  The  striae  converge 
towards  the  umbilicus,  their  pimcta  near 
the  margin  are  closer  and  more  distinct, 
forming  a  broad  border. 

8  *  Transverse  strice  and  conspicuous 
margin. 

C.  coronata  (Bri.). — Valve  oval ;  striae 
transverse,  reaching  the  conspicuous 
median  line,  smToimded  by  a  costate 
band;  spaces  between  the  costae  punc- 
tate; costae  about  9  in  -001";  striae  15 
in  -001".  Bri  JMS.  vii.  p.  179,  pi.  9.  f.  3. 
Shell  cleanings.  West  Indies.  The  me- 
dian line  reaches  only  to  the  margin  of 
the  band ;  breadth  of  band  -0002". 


872 


SYSTEMATIC  HISTORY  OF  THE  INEUSORIA. 


Cfimhriata  (Fi.^.  —  Valve  oval,  witli 
a  crenate  intramarginal  line  ;  coarse 
transverse  puncta  reaching  the  median 
line.  EB.  1858 ;  Bri  JMS.  vii.  p.  179, 
pl.  9,  f.  43.  Corsican  Algae.  This  species 
18  readily  distinguished  by  its  peculiar 
looped  margin. 

Doubtful  and  undescrihed  Species. 

C.  Navicula  (E). — Striated ;  the  navi- 
cular side  ovate ;  the  front  view  narrow- 
linear,  with  an  obscure  median,  lon^- 
tudinal  fui-row.  KSA.  p.  63.  Baltic, 
parasitic  on  Bacillaria  paradoxa.   1-864". 

C.  paradoxa,  EM.  pl.  9.  2.  f.  5.  Fossil. 
Puy  de  Dome.  Figures  small,  elliptic, 
smooth,  with  one  or  two  median  longi- 
tudinal lines  and  no  nodule. 

C.  Britannica  (Nag.). — Large,  elliptic, 
smooth,  with  an  accessory  limb,  mar- 
ginal outwardly  curved  lines,  and  a  di- 


stinct median  nodule.  KSA.  p.  890.  On 
British  Algae. 

C.  tefiuissima  (Nag.).  —  Elliptic,  very 
thin,  with  concave  venter  and  con- 
vex dorsum,  sometimes  with  a  narrow, 
opaque,  crenulated  limb.  KSA.  p.  890. 
On  British  marine  Algae.  Varies  in 
breadth  and  in  presence  or  absence  of 
striae  and  accessory  border. 

C.  disciformis  (E.),  C  navicularis  (E), 
C.  Scutum  (E.),  Swan  River  ;  C.  stellata 
(E.),  C.  undata  (E.),  Western  Asia;  C. 
tumida  (E.),  River  Jordan ;  C.  acuta  (E.), 
Ural  Mountains ;  C.  turgida  (E.),  Siberia ; 
C.  Indica  (E.),  C.  Bramapiitra  (E.),  C. 
angusta  (E.),  India;  C.  Sol  (E.),  Oasis 
of  Jupiter  Ammon,  Africa ;  C.  Stella  (E), 
Teneriffe ;  C.  Glans  (E.),  C.  Brasilieiisis 
(E.),  C.  lirata  (E.),  Brazil;  C.  Morrisii 
(S.),  Black  Sea. 


FAMILY  XV.— ACHNANTHE^. 

Frustnles  genuflexed  downwards,  either  free,  adnate,  or  stipitate,  each 
lateral  surface  having  a  median  longitudinal  line  and  the  inferior  one  a 
central  nodule  or  stauros  also.  The  Achnantheae,  like  the  Cocconeideae,  have 
a  nodule  only  on  the  inferior  valve;  but  this  is  almost  the  only  point  of 
resemblance.  The  bent  frustule  and  dissimilar  lateral  surfaces  distinguish 
this  family  from  every  other.  In  their  mode  of  growth  the  Achnantheas 
resemble  the  Biddulphieae. 

Genus  ACIINANTHIDIUM(Kutz.).  — Frustnles  unattached,  solitary  or 
few  together,  rarely  numerous,  in  front  view  linear,  bent ;  ventral  valve  with 
median  line  and  central  and  terminal  nodules ;  dorsal  valve  without  a  central 
nodule.  The  Achnanthidia  resemble  unattached  frustnles  of  Achnanthes,  but 
are  generally  very  minute,  and  their  proper  position  is  stiU  somewhat  doubtful. 
''  Admitting  it  to  be  proved  that  in  the  species  of  this  genus  there  positively 
exists  a  median  nodule  in  one  of  the  lateral  surfaces  and  not  in  the  other, 
and  that  two  puncta  exist  in  the  extremities  of  the  primary  surfaces,  as 
stated  in  the  definition  of  the  order  and  in  that  of  the  family, — admitting  this, 
we  should  still  have  to  decide  whether  the  uncertain  relations  of  these  cha- 
racters to  other  families,  and  their  inconstancy,  will  give  us  any  right  to 
erect  a  distinct  genus  on  principles  so  slight  and  precarious  "  (Meneghirii). 

rounded ;  striae  obscure.  =  Navicula  tri- 


*  Frustules  minute,  smooth  or  obscurely 
striated. 

AcHNANTHiDiuM  microceplialum  (K.). 

—  Frustules  extremely  minute ;  valves 
lanceolate,  with  capitate  apices ;  striae 
obsolete.  KB.  p.  75,  pl.  3.  £  13  &  19 ; 
SBD.  ii.  p.  31,  pl.  61.  f.  380.  Fresh 
water.  Em-ope.  (xiv.  15.)  Front  view 
narrow-linear.     1-1680". 

A.  trinode  (Ar.).  —  Frustules  genicu- 
late; valves  with  one  central  and  two 
terminal  inflations ;  median  line  and 
central     nodule     distinct  ;    extremities 


nodis,  SBD,  ii.  p.  94.  Fresh  water. 
Britain,     {yiu.  9.) 

A.  lanceolatum  (Breb,).  —  Frustules 
minute ;  valves  oblong-lanceolate,  with 
obtuse  ends  and  turgid  centre ;  striae 
obscure.  Breb.  in  KSA.  p.  54 ;  SBD.  ii. 
p.  30,  pl.  37.  f.  304.  Fresh  water.  Eu- 
rope. Frustules  2  to  100;  striae  40  in 
•001",  S.  The  transverse  band  of  the 
lower  valve  sometimes  extends  to  both 
margins,  sometimes  is  bifid,  and  on  one 
half  only. 

K,  delicatidum  (K.). —Frustules  mi- 


OF  THE  AC^^^\NT^E^. 


873 


nute ;  valves  ventricose,  with  rostrate 
ends.  KB.  p.  75,  pi.  3.  f.  21.  Falcatella 
delicatula,  Rab  D.  p.  46,  t.  5.  f.  4.  Sub- 
marine.   Germany,    (xiv.  16.)    1-1680". 

A.  cryptoceplialum  (Nag.).  —  Valves 
lanceolate  -  linear,  with  the  subacute 
apices  attenuated  or  obsoletely  capitate. 
Nag.  in  KSA.  p.  890.     S^^-itzerland. 

A.  lineare  (S.).  —  Frustules  minute ; 
valves  linear,  obtuse,  upper  with  median 
line  only,  lower  with  median  line  and 
nodules;  sti-ise  obscure.  SBD.  ii.  p.  31, 
pi.  61.  £381.    Freshwater.    Scotland. 

A.JlexeUum  (K.,  Breb.). — Valves  ob- 
long, with  gibbous  middle  and  very 
obtuse  ends ;  median  line  sigmoid.  Breb. 
KSA.  p.  54.  =  Cymhella  {?)JlexeUa,  KB. 
p.  80,  pi.  4.  f.  14 ',  Rab  D.  p.  23,  pi.  7.  f.  15 ; 


Achnanthes  Bavariea,  ERBxA..  1853,  p. 
526;  Cocconeis  Thwaitesii,  SBD.  i.  p.  21, 
pi.  3.  f.  33.  Fresh  water.  Europe. 
1-650" ;  striae  indistinct ;  front  view 
^vdth  genuflexed  venter,  convex  dorsum, 
obtuse  ends,  and  a  notch-like  punctum 
at  the  middle  of  the  lower  margin. 

2  *  Frustules  large,  distinctly  striated. 

A.  coarctatum  (Breb.). — Valves  elon- 
gated, linear- oblong,  constricted  at  the 
middle,  with  slightly  attenuated,  obtuse 
ends,  striae  distinct.  Breb.  in  SBD.  ii. 
p.  31,  pi.  61.  t.  379.  =  Achnanthidimn 
Otrantinum,  Rab  D.  p.  25,  pi.  8.  f.  3 ; 
Achnanthes  binodis,  EM.  pi.  34.  5  B.  f.  1  ?. 
Fresh  water.  Europe,  Africa,  America. 
(VII.  41.) 


Genus  ACHNANTHES  (Bory  St.-Vinc,  Ag.).  —  Fnistules  bent,  solitary 
or  aggregate,  attached  to  a  stipes,  a  central  nodule  in  the  lower  or  ventral 
valve  only.  The  fmstiiles  are  bent  downwards  ;  so  that  the  ui)per  margin  is 
convex,  the  lower  one  concave.  In  some  species  the  lateral  portions  are 
turgid,  the  central  one  looking  like  a  band  between  them ;  in  others  they  do 
not  enter  into  the  front  view.  The  superior  lateral  surface  differs  from  the 
lower  in  the  absence  of  the  central  transverse  pellucid  line  and  central  nodule, 
the  latter  appearing  like  a  punctum  in  the  front  view.  A  median  longitu- 
dinal line  is  present  in  both  valves.  In  their  obscure  striae  "  three  species 
{minutissima,  exilis,  parvula)  present  great  analogy  of  form  with  the  pre- 
ceding genus.  In  one  of  these  (parvula)  there  is  wanting  the  characteristic 
angular  bending,  for  which  reason  it  becomes  very  similar  to  Odontidium 
and  Diadesmis.  The  other  species  (striatce)  differ  only  by  verj'  slight  cha- 
racters fi'om  each  other  "  (Meneg.). 


*   Valves  divided  by  two  constrictions 
into  three  lobes. 

Achnanthes  ventricosa  (E.). — Valves 
divided  by  two  constrictions  into  three 
oblong  inflations ;  apices  roimded  ;  striae 
distinct.  EM.  t.  1.  2.  f.  9 ;  t.  1.  3.  f.  18, 
ld.=3Ionoyra?nma  ventricosa,  E.  Asia, 
Africa,  America. 

2  *  Valves  distinctly  striated,  not  three- 
lobed.     Ifarine. 

t  Valves  costate. 

A.  longipes  (Ag.). — Gregarious ;  valves  j 
elliptic-oblong,  costate,  with  monilifonn  | 
striae  between  the  costae.     ASA.  p.  1 ;  I 
KB.  p.  77,  ph  20.  f.  1;  SBD.  ii.  p.  26, 
f.  300.  =  Conferva  stipitata,  Eng.   Bot. 
t.  2488 ;  A.  Carinichaelii,  Grev.  in  Br.  Fl. 
ii.  p.  404.    {yii.  42.)     On  Marine  AlgJB.  I 
Em-ope,  America.     Few-pointed ;  frus-  I 
tules  large,  with  stout  elongated  stipes ;  I 
front  view  turgid,  with  convex  dorsmn.  ; 
1-570"  to  1-120".  I 


2 1  Valves  striated,  but  not  costate. 

A.  brevipes  (Ag.). — Gregarious ;  valves 
oblong,  with  attenuated  acute  ends ;  striae 
distinct,  monilifonn,  20  in  -001";  stipes 
stout,  short.  Ag  CD.  p.  59 ;  SBD.  ii.  p.  27, 
pi.  37.  f.  301.  Marine.  Em-ope,  Ame- 
rica.^ (x.  199-202.)  Frustules  large,  very 
turgid  in  front  view,  with  convex  dor- 
sum.    1-860"  to  1-180". 

A.  salina  (K.).  —  Frustules  striated, 
very  turgid,  obtuse-angled,  genuflexed, 
with  slightly  notched  venter ;  valves 
broadly  linear,  ^dth  cuneate  ends ;  striae 
punctated ;  stipes  very  short,  thick.  KB. 
p.  77,  pi.  20.  f.  5.  Salt  marshes.  Europe. 
Differs  from  A.  brevipes  only  in  its  more 
linear  valves  and  cimeate  ends.  Professor 
Smith  was  probably  right  in  uniting 
them. 

A.  intermedia  (K.).  —  Few-jointed ; 
frustules  striated,  obtuse-angled,  turgid; 
valves  sublinear,  with  acutely  cuneate 
ends;  stipes  short,  distinct,  fine.  KB. 
p.  76,  pi.  20.  f.  6.  On  Enteromorpha 
intestinalis.    Germany,  France.     Smaller 


874 


SYSTEMATIC  HISTOET  OF  THE  IN^FUSOEIA. 


than  A.  hrcvipes,  with  less  turgid  dorsum 
and  finer  stria3 ;  but  we  doubt  whether 
the}'  are  truly  distinct. 

A.  7'homboides  (E.). — Frustules  large, 
striated,  very  tiu'gid,  nearly  straight; 
valves  broadly  lanceolate,  almost  rhom- 
boid, with  acute  apices;  stipes  short, 
thick.  EA.  p.  121.  =  A.  ventncosa,  KB. 
p.  76,  pi.  20.  f.  7.  Marine.  America, 
Europe. 

A.  multiarticulata  (Ag.).  —  Frustules 
striated,  turgid,  with  rather  obtuse 
angles  -,  valves  elliptic-lanceolate ;  stipes 
stout,  short.  Ag  CD.  p.  59 ;  KB.  p.  76, 
pi.  20.  f.  8.    Marine.    Em-ope.    1-312". 

A.  Capensis  (K.). — Frustules  striated, 
turgid,  obtuse-angled ;  valves  lanceolate- 
elliptic  or  oblono- ;  stipes  elongated,  stout. 
KB.  p.  76,  t.  21.  £  1.  Marine.  Cape 
of  Good  Hope.  1-600".  It  varies  with 
few  or  many  frustules. 

A.  ba cilia r is  (E.). — Frustules  narrow, 
striated,  each  slightly  inflexed  at  the 
middle,  both  dorsally  and  ventrally 
equally  bacillar,  with  rounded  ends ; 
stipes  short.  ERBA.  1843,  p.  256.  Ma- 
rine. Venice.  Often  in  long  series.  It 
is  smaller  than  A.  longipes,  and  more 
slender  than  A.  brevijjes,  E. 

A.  subsessilis  (K.). — Scattered,  of  few 
frustides  ;  valves  linear-oblong,  with 
romided  ends;  striae  monilifonn,  24  in 
•001";  stipes  nearly  obsolete.  KB.  p.  76, 
t.  20.  f.  4;  SBD.  ii.  p.  28,  pi.  37.  f.  302.= 
Aclinanthes  turgens,  EA.  p.  121.  Common 
on  filiform  species  of  Enteromorpha  in 
salt  marshes.  Europe,  America.  1-1150" 
to  1-430".  (vii.  43.)  Easily  recognized 
by  its  all  but  sessile  frustules. 

A.  angustata  (Grev.).  —  Front  view 
nan-ow;  length  0060" ;  breadth -0004" ; 
strict  24  in  -001".  ^  Grev  MJ.  vii.  p.  163, 
pi.  8.  f.  9.  In  Californian  guano.  "  The 
striiB  agree  in  number  with  those  of 
A.  subsessilis;  the  relative  length  and 
breadth,  however,  of  the  valve,  as  seen 
in  the  front  view,  is  so  widely  different 
from  the  proportions  of  the  species  above 
mentioned,  that  the  possibility  of  its 
being  a  varietv  cannot  be  entertained" 
(GrevHle). 

A.  cristata  (Rab.). — Valves  oblong- 
elliptic;  striae  gently  cmwed,  coarsely 
monilifonn,  distant,  9  to  10  in  -001". 
Rab  D.  p.  26,  pi.  8.  f.  7.     Italy. 

K.  genujiexa  (K.). — Frustules  small, 
striated,  turgid,  obtuse-angled,  strongly 
bent ;  stipes  short,  rather  stout.  IvB. 
p.  76,  pi.  21.  f.  3.     Marine.     Genoa.  ^ 

A.  Gregoriana  (Grev.).  —  Front  view 
of  frustule  broadly  linear;  striae  very 
fine ;  leng-th  -0060"  to  -0080" ;  breadth 


•0010"  to  -0015".  Grev  MJ.  vii.  p.  84, 
pl._  6.  f.  13,  14.  Marine.  Scotland.  In 
point  of  size  it  rivals  A.  longipes,  but  is 
widely  separated  from  it  in  the  character 
of  the  striation  alone,  to  perceive  which 
requires  not  only  a  good  object-glass  but 
delicate  manipulation.  As  in  many  of 
its  congeners,  the  frustules  var}^  gTeatly 
in  both  length  and  breadtli  (Grev.). 

A.  pachypus  (Montague).  —  Frustules 
sniaU,  finely  striated,  obtuse-angled, 
rather  turgid  ;  valves  elliptic-oblong ; 
stipes  stout,  very  short.  Mont.  Flor. 
Boliv.  pi.  1 ;  KB.  p.  76,  pi.  29.  f.  83. 
Marine.  Europe,  Asia,  America.  1-1730" 
to  1-1320". 

A.  parvula  (K.).  —  Frustules  minute, 
nearly  straight,  obtuse-angled ;  valves 
elliptic-oblong,  obtuse,  finely  striated; 
stipes  rather  stout.  KB.  p.  76,  t.  21.  f.  5. 
On  Enteromorpha  in  brackish  water. 
Europe.  Frustules  stouter  than  in  A. 
exilis. 

3  *  Very  mitiute ;  strice  wanting  or 
indistinct.     Fresh  water. 

A.  exilis  (K.).  —  Frustules  slender, 
linear ;  valves  lanceolate,  tapering  to 
the  subacute  apices ;  striae  indistinct ; 
stipes  slender,  elongated.  KB.  p.  76, 
t.  21.  f.  4 ;  Rails,  ANH.  xiii.  p.  14.  f.  12 ; 
SBD.  ii.  p.  29.  Fresh  water.  Europe, 
Asia,  America.  (^t:i.  44.)  A.  exilis  is 
easily  knoviii  by  its  minute,  slender, 
hyaline  frustules  from  every  other  spe- 
cies except  A.  minutissima.  From  that 
species  it  differs  by  its  tapering,  more 
lanceolate  and  acute  valves,  and  by  its 
elongated  stipes. 

A.  minutissima  (K.). — Frustules  slen- 
der, linear;  valves  linear-oblong,  with 
rounded  ends  ;  striae  obsolete ;  stipes 
fine,  shorter  than  the  fr'ustule.  KB. 
p.  75,  pi.  13.  f.  2  c ;  Ralfs,  ANH.  xiii.  pi.  14. 
f.  11.  Fresh  water.  Em-ope.  We  for- 
merly considered  this  a  variety  of  A. 
exilis,  and,  still  doubting  whether  the 
differences  are  constant,  think  that  Pro- 
fessor Smith  may  rightly  have  united 
them. 

Doubtfid  Species. 

A.?  arenicola  (Bail.). — Frustides  mi- 
nute, rectangular  or  slightly  curved ; 
valves  lanceolate,  striate ;  stipes  short. 
Bail.  Sm.  Cont.  ii.  p.  38,  pi.  2.  f.  19. 
Marine.  America.  It  is  possibly  a  spe- 
cies of  Hvalosira,  but  requires  frirther 
study  (Bail.). 

A.  austraJis,  EM.  pi.  35  a.  2.  I  1. 
South   Africa.      Frustules   linear,   uni- 


OF  THE  CYMBELLE^. 


875 


formly  curved,  with  truncate  ends  and 
striated  margin. 

A.  ?  incequalis  (E.).  — Unequally  bent 
and  smooth.  EM.  pi.  16.  1.  f.  45,  & 
pi.  17.  2.  f.  25.    Fossil.    Sweden,  Finland. 

A./^  jjaradoxa  (E.). — Frustules  ovate, 
obtuse,  twice  as  long  as  broad,  with  16 
transverse,  scabrous,  pimctated  lines  in 
1-1152".     ERBA.  1845,  p.  73.      Fossil. 


United  States.    1-900".     No  nodule  ob- 
served, E. 

Species  known  to  us  only  hy  name. 

A.  turgida  (E.),  Australia,  America ; 
A.  Indica  (E.),  India;  A.  Javanica  (E.), 
Java;  A.  ohtusa  (E.j,  Africa;  A.  Semen 
(E.),  America;  A.  Brasiliensis  (E.),  Bra- 
zil ;  A.  incrasscda  (E.),  America. 


Genus  CYMBOSIRA  (Kiitz.). — Frastules  as  in  Achnanthes,  stipitate,  con- 
nected into  series  by  a  gelatinous  process  or  hinge  (isthmus).  CjTnbosira 
differs  from  Achnanthes  by  the  same  character  as  Diatoma  from  Fragilaria. 


Cy]MB0Slra  Af/ardhii  (K.).  —  Frus- 
tules linear,  slightly  cmwed,  with  rounded 
apices;  valves  linear,  oblong,  scarcely 
dilated  at    the    middle,   \N'ith   rounded 


obtuse  apices.  KB.  p.  77,  pi.  20.  f.  3. 
=  Achnanthes  seriata,  AgCl).  Marine. 
Venice,  Cayenne,  (xiv.  14.).  1-960"  to 
1-288".     Stipes  very  short. 


Genus  MONOGEAMMA  (Ehr.). — Frustules  fiu^nished  with  transverse  pin- 
nules, a  median,  transverse,  linear  band  on  one  valve  only,  three  ventral 
nodules  and  two  dorsal.  ( =  Stauroptera  with  a  stam^os  on  one  valve  only,  or 
to  a  solitary  Achnanthes  with  terminal  pimcta. — ERBA.  1843,  p.  136.)  Not- 
withstanding Ehrenberg's  remarks,  we  cannot  dLstinguish  this  genus  from 
Achnanthidium.     The  species  are  known  to  us  only  by  name. 


MoNOGRAirNiA  Achuanthes  (E),  India. 
M.  trinodis  (E.),  Sandwich  Islands. 


M.  ventricosa  (E.) 
tricosa. 


Achnanthes  ven- 


FAMILY  XVI.— CYMBELLE^. 

Frustules  cymbiform;  valves  lunate,  with  a  longitudinal  line,  and  mar- 
ginal or  subcentral  nodule.  In  shape  the  Cymbellese  are  very  similar  to  the 
Eunotieae,  but  they  differ  essentially  both  from  them  and  the  Naviculeee  by 
the  median  nodules  of  the  lateral  surfaces  being  marginal  or  submarginal. 

Genus  CYMBELLA  (Ag.,  Kiitz.). — Frustules  free,  C3'mbiform  ;  transverse 
striae  interrupted  by  a  longitudinal  line  having  central  and  terminal  nodides, 
and  di\iding  the  valve  into  unequal  portions.  The  frustules,  in  the  lateral 
view,  have  one  margin  (dorsum)  convex,  and  the  other  (venter)  straight,  or 
at  least  less  developed.  In  consequence  of  this  form,  the  longitudinal  line 
divides  the  surface  unequally,  being  much  nearer  the  lower  margin.  CymbeUa 
includes  species  distributed  in  the  genera  Cocconema,  Navicula,  and  Pinnu- 
laria  of  Ehrenberg's  system. 


*  Valves  ii'ith  one  margin  triundulate. 

CY:yiBELLA  Areas  (Greg.),  —  Valves 
slender,  semilanceolate,  with  straight 
venter,  convex,  triundulate  dorsum,  and 
produced,  minute,  capitate  apices.  Greg, 
in  MJ.  iv.  p.  6,  pi.  1.  f.  21 ;  SBD.  ii. 
p.  85.  Scotland.  Minute  ;  longitudinal 
line  and  nodules  submarginal ;  transverse 
stri«  very  fine,  40  in  -001".  [  VU .  JV 

C.  sinuata  (Greg.  J. — Valves  lanceolate, 
with  subcapitate  apices,  gently  convex 
dorsum,  and  triundulate  venter.  Greg. 
MJ.  iv.  p.  4,  pi.  1.  f.  ]7.  Scotland. 
Minute ;    transverse    striae    conspicuous. 


about  20  in  -001",  scarcely  reaching  the 
median  line. 

2*  Valves  without  triundulate  margins. 

t  Valves  with  produced  or  capitate 
j  apices. 

I      C.  Ehrenhergii  (K-)- — Yalves  broadly 
I  lanceolate,  -«4th  imequal  sides,  suddenly 
I  contracted   into  rather   obtuse,  slightly 
I  produced   apices ;    transverse   strise    di- 
stinct, punctate,  12  in  1-1200".  KB.  p.  79, 
t.  6.  f.  11 ;  SBD.  i.  p.  17,  pi.  2.  f.  21.  ^Na- 
vicida  incequalis,  E  Inf.  t.  13 ;  Timndaria 
incequalis,  EM.  many  figures.     Common, 


876 


SYSTEMATIC  HISTORY  OF  THE  INFUSOEIA. 


both  recent  and  fossil.  Europe,  Asia, 
Afi-ica,  America.  (vii.  46 ;  ix.  154.) 
Large ;  length  1-216".  Differs  from  a 
Navicula  only  in  having  one  margin  of 
the  valves  less  convex  than  the  other. 

C.  heteropleura  (E.,  K.).  —  Valves 
broadly  lanceolate,  with  unequally  con- 
vex sides,  suddenly  contracted  into  short, 
broad,  very  obtuse,  beak-like  apices ; 
striae  distinct.  KB.  p.  19.  =  Plmiulana 
heteropleura,  EM.  pi.  5.  2.  f.  11.  North 
America.  Large ;  allied  to  C.  JEhren- 
hergii,  but  with  more  obtuse  apices. 

C.  cuspidata  (K.). — Valves  broadly 
lanceolate,  with  unequally  convex  sides, 
suddenly  contracted  into  subacute,  short, 
rostrate  apices ;  strise  delicate,  18  to  20 
in  1-1200".  KB.  p.  79,  t.  3.  f.  40 ;  SBD.  i. 
p.  18,  pi.  2.  f.  22.  Europe.  1-576". 
(^11.  45.)  Differs  from  the  preceding 
species  in  its  smaller  size,  more  graceful 
form,  and  narrow  beaks. 

C.  rostrata  (Rab.).  —  Valves  semilu- 
nate,  wdth  dorsum  strongly  and  venter 
slightly  convex ;  ends  produced  into 
short,  subacute  beaks ;  striae  dotted,  con- 
verging, 12  or  13  in  1-1200".  Rab  D. 
p.  22,  pi.  7.  f.  5.  Italy.  SmaU.  Very 
nearly  allied  to  C.  cuspidata. 

C.  porrecta  (Rab.).  —  Valves  turgid- 
lanceolate,  with  unequal  margins ;  ends 
produced  into  rather  long,  stout,  obtuse 
beaks ;  striae  stout,  somewhat  converg- 
ing, 6  in  1-1200".  Rab  D.  p.  22,  pi.  10. 
f.  10.  Italy.  Venter  less  turgid  than 
the  dorsum. 

C.  fortncata  (Rab.). — Valves  lunate, 
with  very  fine  convex  dorsum,  gibbous 
venter,  and  produced,  obtuse,  rostrate 
ends ;  striae  fine,  smooth,  7  or  8  in 
1-1200".  Rab  D.  p.  22,  pi.  10.  f.  9. 
Persia. 

C.  amphicephala  (Nag.).  —  Smooth  ; 
valves  elliptic,  with  unequal  sides  and 
produced  capitate  apices;  front  view 
oblong  with  truncate  ends.  KSA.  p.  890. 
Switzerland. 

C.  cequalis  (S.). — Valves  lanceolate, 
nearly  symmetrical,  with  shortly  pro- 
duced, slightly  curved,  obtuse  extre- 
mities :  stride  fine,  30  in  -001".  SBD.  ii. 
p.  84 ; '  Grev.  in  ANH.  2  ser.  xv.  pi.  9. 
f.  4.  Britain.  A  very  distinct  species, 
which  differs  from  Navicula  only  by  the 
slightly  curved  ends,  Grev. 

O.pachycephala  (Rab.). — Valves  semi- 
lunate,  curved,  with  veiy  convex  dorsum 
and  gibbous  venter,  sti'ongly  constricted 
beneath  the  produced  capitate  apices: 
striae  granulate,  somewhat  converging, 
7  or  8  in  1-1200".  ^  Rab  D.  p.  22.  =  C. 
eurycephala,  Rab.  t.  7.  f.  10.     Servia. 


C.  epithemtoides  (Rab.). — Valves  arcu- 
ate, with  convex  dorsum,  concave  venter, 
and  produced,  obtuse,  slightly  recm-ved 
ends ;  striae  stout,  somewhat  converg- 
ing, 6  in  1-1200".  RabD.  p.  22.=  a 
costata,  Rab.  t.  7.  f.  16.  Salzburg. 
Like  an  Epithemia,  but  having  a  central 
nodule. 

C.  Gregorii  (Ralfs). — Valves  arcuate, 
with  convex  dorsum,  straight  venter,  and 
Slightly  produced  truncate  apices ;  striae 
distinct.  =  C.  truncata,  Greg,  in  MJ.  iii. 
p.  38,  pi.  4.  f.  3.     Scotland.     Small. 

C  turgida  (Greg.).  —  Valves  lunate, 
with  turgid,  convex  dorsum,  nearly 
straight  venter,  and  produced,  minute, 
acute  apices;  striae  very  conspicuous, 
about  24  in  -001".  Greg  MJ.  iv.  p.  5, 
pi.  1.  f.  18.     Scotland,  America. 

C.  Pisciculus  (Greg.). — Valves  lanceo- 
late, with  convex  dorsmn,  nearly  straight 
venter,  and  obtuse,  subcapitate  apices; 
strijE  about  30  in  -001".  Greg,  in  MJ. 
iv.  p.  6,  pi.  1.  f.  20.     Britain. 

C  excisa  (K.). — Valves  semilunate, 
with  slightly  recm-ved,  produced  apices, 
very  convex  dorsum,  and  a  straight 
venter,  notched  at  its  middle ;  striae  16 
in  1-1200".  KB.  p.  80,  pi.  6.  f.  17. 
Europe.     Minute. 

2 1  Apices  neither  rostrate  nor  capitate. 

C.  affinis  (K.).  —  Valves  lanceolate, 
with  subacute,  scarcely  produced  apices, 
and  the  dorsal  margin  more  convex  than 
the  ventral ;  striae  faint,  19  in  1-1200". 
IvB.  p.  80,  pi.  6.  f.  15 ;  SBD.  i.  p.  18,  pi.  30, 
f.  250.  =  Cocconema  Fusidium,  EM.  many 
figm'es.  Europe,  Asia,  Australia,  Africa, 
America.  Minute;  terminal  nodides 
large.     1-1150"  to  1-620". 

C.  delicatula  (K.). — Valves  imequally 
and  narrowly  lanceolate,  smooth.  KSA. 
p.  59.     France.     Minute.     1-1200". 

C.  ohtmiuscula  (K.). — Valves  lanceo- 
late, with  one  margin  rather  less  convex 
than  the  other ;  apices  somewhat  obtuse, 
not  produced;  striae  fine,  18  to  20  in 
1-1200".  KB.  p.  79,  pi.  3.  f.  68.  Europe. 
1-600".  Differs  from  a  Na\-icida  only  by 
its  slightly  imequal  margins. 

C.  Helvetica  (K.). — Valves  elongated, 
somewhat  arched,  slender-lanceolate, 
with  slightly  gibbous  venter,  and  rather 
obtuse  apices  ;  striae  fine,  granulated,  13 
or  14  in  1-1200".  SD.  i.  p.  18,  pi.  2.  f.  24. 
Europe,  (xi v.  24-28.)  Large.  1-264" 
to  1-240".  Front  view  oblong,  trim- 
cate.  Akin  to  C.  gastroides,  but  more 
slender,  K. 

C.  maxima  (Nag.). — Valves  slender, 
with  attenuated,  rather  obtuse  ends,  and 


OF  THE  CYMBELLE.E. 


8^ 


inflated  venter ;  striae  16  in  1-1200." 
KSA.  p.  890.  Switzerland.  1-180"  to 
1-120". 

C.  gastroides  (K.). — Valves  lunate, 
with  obtuse  apices  ;  venter  sliglitly  con- 
cave, with  gibbous  centre ;  striae  granu- 
lated, 11  or  12  in  1-1200".  KB.  p.  79, 
pi.  6.  f.  4  6.  Eui'ope.  (xiY.  18-20.) 
Large. 

C.  truncata  (Rab.). — Valves  as  in  C. 
gastroides,  but  with  broadly  truncate 
apices.  Rab  D.  p.  21 ;  C.  fulva,  t.  7.  f.  3. 
=  C.  gastroides,  KB.  p.  79,  pi.  6.  f.  4  a. 
Eiu'ope. 

C.  leptoceras  (E.,  K,). — Valves  slender, 
arcuate,  with  gibbous  venter  and  attenu- 
ate apices  ;  striae  veiy  fine,  17  in  1-1200". 
KIB.  p.  79,  pi.  6.  f.  14.  =  Cocconema  lep- 
toceras, EA  and  M.  many  figures.  Eu- 
rope, Asia,  Australia,  Africa,  and  Ame- 
rica. Minute  ;  front  view  elliptic-oblong, 
with  rounded  ends. 

C.  macidata  (K.). — Valves  semiorbicu- 
lar,  with  very  convex  dorsimi  and  straight 
or  gibbous  venter  ;  striae  very  fine,  12  to 
13  in  1-1200".  KB.  p.  79,  pi.  6.  f.  2.  = 
C.  Lumda,  Rab  D.  p.  23.  =  Cocconema 
Lunula,  EA  and  M.  many  figures.  Com- 
mon. Europe,  Asia,  Africa,  America. 
Minute ;  front  view  elliptic,  with  trun- 
cate ends. 

C.  ohtusa  (Greg.). — Valves  semi-oval, 
with  very  obtuse  apices,  convex  dorsum, 
and  nearly  straight  venter;  striae  very 
fine,  inconspicuous,  about  36  in  -001". 
Greg  MJ.  iv.  p.  5,  pi.  1.  f.  19.  Scotland. 
Minute. 

C.  ventricosa  (Ag.). — Valves  semilu- 
nate,  with  very  convex  dorsum,  straight 
venter,  and  large,  distinct  terminal 
nodules ;  striae  inconspicuous,  30  in 
•001".  Ag  CD.  p.  9;  KB.  p.  80,  pi.  6. 
f.  16;  SBD.  ii.  p.  84.     Em-ope.    Minute. 


1-1000".  Front  view  oblong,  with  trun- 
cate ends. 

C.  inicrostoma (Rab.). — Valves  lunately 
curved,  with  broadly  obtuse  ends ;  dorsum 
convex,  depressed  at  the  centre ;  venter 
concave ;  nodules  verv  minute ;  striae 
smooth,  7  or  8  in  1-1200".  Rab  1).  p.  22, 
t.  10.  f.  3.     Persia. 

C.  Scotica  (S.). — Valves  slender,  semi- 
lanceolate,  "wath  straight  ventral  mai'gin 
and  acute  apices;  striae  42  in  -001". 
SD.  i.  p.  18,  pi.  2.  f.  25.     Britain. 

C.  gracilis  (E.,  K.).  — Valves  slender, 
semilanceolate,  with  straight  or  slightly 
concave  ventral  margin  and  subacute 
apices  ;  striae  very  fine  or  obsolete,  17  in 
1-1200".  KB.  p.  79,  pi.  6.  f.  9.=  Cocco- 
nema  gracile,  EM.  several  figures.  Eu- 
rope, Asia,  Africa,  America.  Lough 
Mourne  deposit.  Small.  1-840"  to 
1-600". 

C.  lunata  (S.). — Valves  narrow,  lunate, 
with  slightly  concave  venter,  and  rather 
obtuse  apices ;  striae  distinct,  24  in 
•001".  SBD.  ii.  p.  84.  Grev.  in  ANH. 
2nd  ser.  xv.  pi.  9.  f.  5.  Scotland.  Di- 
stinguished from  C.  Helvetica  by  its 
smaller  size  and  concave  venter,  and 
from  C.  Scotica  by  its  coarser  striae  and 
obtuse  ends,  Grev. 

C.  eurvata  (Rab.). — Valves  smooth, 
lunate,  with  convex  dorsimi,  slightly  con- 
cave venter,  and  obtuse  ends.  Rab  D. 
p.  23,  t.  7.  f.  14.  6.     Italy. 

C.  ?  Diance,  E.  =  Cocconema  Diance, 
EM.  pi.  15  A.  f.  100  a.  Lough  Mom-ne 
deposit.  Small.  Valves  lunate,  with 
convex  dorsum,  concave  venter,  and  ob- 
tuse apices. 

C.  ?  Navicida  =  Cocconema  Namcula, 
EM.  pi.  17.  2.  f.  35.  Finland.  —Valve 
lanceolate,  with  the  dorsum  rather  more 
convex  than  the  venter. 


Genus  COCCONEMA  (Ehr.).  —  Frustules  cymbiform,  stipitate  ;  lateral 
surfaces  lunate,  striated,  and  divided  unequally  by  a  longitudinal  line  with 
median  and  terminal  nodules.  The  frustules  are  similar  in  form  to  those  of 
CymbeUa,  and  when  detached,  their  proper  genus  is  often  doubtful ;  the  lower 
margin,  however,  is  less  frequently  convex  than  it  is  in  Cymbella. 


Cocconema  lanceolatum  (E.). — Front 
view  lanceolate,  truncate ;  valves  elon- 
gated, arcuate,  or  semilanceolate,  centime 
of  venter  gibbous  ;  striae  moniliform,  21 
in  -001".  EI.  t.  19.  f  6 ;  SBD.  i.  p.  75, 
pi.  23.  f.  219.  Europe,  Asia,  Australia, 
Africa,  America,  (x.  194, 195.)  Length 
1-210"  to  1-120".  Venti-al  margin  of 
frustide  nearly  straight,  with  slightly 
gibbous  centre;  stipes  dichotomous, 
articulated. 


C.  aspei'um  (E.). — Habit  and  size  of 
C.  lanceolatum,  but  with  striae  denticu- 
late or  interrupted  by  puncta.  EM. 
many  figures.  Australia,  Asia,  Ame- 
rica ;  fossil,  France.  1-288".  We  fear 
this  form  is  scarcely  distinct  from  C. 
lanceolatum. 

C.  fossile,  EM.  t.  19.  f.  57.  Greece. 
Ehrenberg's  figm-e  represents  a  smaller 
species  than  C.  asperum,  with  straight 
ventral  margin,  nearly  marginal  longi- 


878 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


tudinal  line  and  nodules,  and  denticulate 
sti'iae. 

C.  Bremii  (Nag.). — Pulvinate ;  valves 
slender,  sublunate,  with  attenuated  ends 
and  obtuse  apices;  striae  very  fine.' 
KSA.  p.  890.  Eocks  in  streams.  Switzer- 
land. Large;  stipes  long,  articulated; 
frustules  in  front  view  lanceolate. 

C.  cornutum  (E.).  — Valves  slender ; 
lunate,  gradually  tapering  into  long  ends, 
with  obtuse  apices ;  venter  concave,  gra- 
dually tumid  at  its  middle.  EM.  pi.  15  a. 
f.  94.  America,  Berlin.  Lough  Mourne 
deposit.  Large ;  differs  from  C.  lanceo- 
latum  in  its  more  slender  and  tapering 
form. 

C.  Mexicammi  (E.).  —  Stout;  valves 
lunate,  with  obtuse,  slightly  produced 
ends ;  ventral  margiu  slightly  tumid ; 
dorsum  very  convex ;  striae  18  in 
1-1152",  distinctlv  and  elegantlv  granu- 
lose.  EM.  pi.  33.  7.  f.  6,  7.  'Mexico. 
Large.     1-206". 

C.  Cistula  (E.). — Valves  lunate,  with 
very  convex  dorsum,  and  the  concave 
venter  tumid  at  its  centre  ;  stipes  elon- 
gated, filiform,  subsimple.  EI.  t.  19. 
f.  7  ;  SBD.  i.  p.  76,  pi.  23.  f.  221.  =  Gom- 
plionema  semi-eUipticum,  Ag  CD.  p.  33 ; 
G.  simplex,  KSA.  p.  37.  Europe,  Asia, 
America.  (x.  196-198.)  1-1150"  to 
1-430".  Front  view  eUiptic-oblong, 
with  obtuse  ends. 

C.  GrcBcum  (E.).— Habit  of  C.  Cistula, 
but  with  stronger  and  fewer  striaB,  12  to 
13  in  1-576".  EKBA.  1840,  p.  12. 
Greece.     1-575". 

C  ?  biceps  (E.). — Valves  turg-id,  semi- 
oval,  each  ends  in  a  flat  and  tumid  mar- 
gin, suddenly  rostrate,  obtuse ;  sides 
longitudinallv  sulcate  and  ti'ansversely 
sti'iate.  ERBA.  1845,  p.  362.  Marine. 
India.    1-576".     Habit  of  C.  Cistula. 

C.  cymhiforme  (Ag.,  E.). — Slender; 
valves  lunate,  with  somewhat  obtuse 
apices;  venter  straight  or  slightly  con- 
cave, with  rather  tumid  centre  ;  stipes 
intricate,  forming  a  compact  gelatinous 
mass.  EI.  pi.  19.  f.  8  ;  SBD.  i.  p.  76, 
pi.  33.  f.  220.  =  Cymhella  cymhiformis, 
Ag  CD.  p.  10 ;  Frustulia  cijmhiformis, 
KSA.  Europe,  Asia,  America,  (xii. 
46.)  1-500"  to  1-150".  Transverse 
striae  16  in  1-1200".  Front  view  linear- 
lanceolate,  with  truncate  ends.  It  fomis 
a  brownish  compact  covering  on  rocks, 
which  is  frequently  of  considerable 
thickness  and  extent. 

C.  ?  ac^dum  (E.).— Slender,  slightly 
cm-ved,  smooth  (?),  with  acute  ends; 
ventral  margin  slightly  tumid  in  the 
middle.  EA.  p.  123.  Labrador,  Falaise  ?. 


Small ;  habit  of  a  curved  Navicula  am- 
phioxys. 

C.  tumiclum  (Breb.). — Valves  semilu- 
nate,  with  obtuse,  scarcely  produced 
ends ;  ventral  margin  nearly  straight ; 
front  view  lanceolate,  with  truncate 
apices.  KSA.  p.  60.  France.  Small. 
1-576".  Striae  16  in  1-1200".  Stipes 
elongated,  filiform,  simple. 

C.  affine  (K.). — ^^"alves  lunate,  with 
very  convex  dorsum;  stipes  intricate. 
KSA.  p.  59.  France.  Minute.  Resembles 
Cymhella  affinis,  but  is  stipitate. 

C.  gihhum  (E.). — Valves  semielliptic, 
with  trimcate,  slightly  produced  apices  ; 
transverse  striae  verv  delicate.  KB.  t.  6. 
f.  6.  Europe,  Asia."  (xm.  10.)  1-480". 
jS  sessile.  Stipes  obsolete.  =  Cymhella 
Orsiniana,  Rab  D.  p.  23. 

C.  Arms  (E.). — Semiluuate,  with  ob- 
tuse apices ;  dorsum  very  convex,  venter 
not  gibbous.  EM.  several  figures.  Asia, 
America,  Lough  Momne  deposit. 

C.  jmrvum  (S.). — Valves  lunate,  with 
subacute  ends;  ventral  margin  scarcely 
gibbous ;  front  view  nearly  linear.  SBD. 
i.  p.  76,  pi.  23.  f.  222.  (vii.  47.)  Cliff; 
BeachvHead.  Minute.  -0009"  to -0016". 
Strict  21  in  -001". 

C.  Saxonicmn  (Rab.). — Valves  semi- 
lunate,  with  acute  ends  ;  ventral  margin 
straight  or  slightly  concave  ;  dorsum  very 
convex  ;  sti'iae  faint.  Rab  1).  p.  24,  t.  10. 
f.  11.  Saxony.  Minute.  The  front 
xiew  is  figured  as  oblong,  with  tnmcate 
ends,  and  the  stipes  dilated  beneath  the 
frustule. 

C.  Boechii  (E.). — ^^^alves  elongated, 
lanceolate,  with  subacute  apices  ;  front 
\dew  linear-lanceolate,  obtuse  ;  striae  ^Q 
in  1-1200".  E  Inf.  t.  19.  f.  5.  =  Gomplm- 
nema  lanceolatum,  Ag  CD.  p.  34;  Don/- 
phora  Boeckii,  SBD.  i.  p.  77,  pi.  24.  f.  223. 
Marine.  Europe.  Large.  1-210"  to 
1-120.  Stipes  dichotomously  divided. 
(^^I.  48.)  This  species  is  no  doubt 
wrongly  referred  to  Cocconema,  since 
both  margins  of  the  lateral  valves  are 
symmetrical.  We  regard  it  as  a  stalked 
Navicula,  and  find  a  central,  though  in- 
conspicuous, nodule — a  fact  which,  we 
think,  forbids  it  being  placed  in  Dory- 
phora  as  Professor  Smith  proposed. 

Species  known  to  us  only  hy  name. 

C.  subtile  (E.),  Asia,  America;  C. 
cingulatum  (E.),  Georgia;  C.  Javam- 
cum  (E.),  Java;  C.  AraucanicB  (E.), 
America. 


OF  THE  CYMBELLE^. 


879 


Genus  SYXCYCLIA  (Ehr.) — Friistnles  cymbiform,  connected  in  a  circular 
manner  ^thin  an  amorplious  gelatinous  substance.  "  Whenever  the  lateral 
siufaces  are  inclined  to  each  other  by  the  different  extension  of  the  two  pri- 
mary surfaces,  the  associated  series  must  be  formed  circularly"  (Meneg.). 

Syncyclia  Sal2)a  (E.).  —  Fnistules 
semi-oval,  smooth,  mostly  connected,  in 
sixes,  into  short  tubes  or  rino;s :  colom"- 


ing  matter  pale  gTeen.  E  Inf.  p.  233, 
t.  20.  f.  11 ;  KSA.  p.  61.  Marine,  near 
Wismar.  (vn.  53  ;  x.  206.)  Length 
1-2300"  to  1-570".  When  dry,  longi- 
tudinally plicate. 

S.  quaternaria  (E.). — Fnistules  binate 


or  quatemate,  smooth ;  coloming  matter 
golden-  or  reddish-bro'.%ai.  EliBA.  1840, 
p.  22 ;  KSA.  p.  61.  Marine.  Europe. 
1-864". 

SiJecies  Jmotoi  to  us  only  by  name. 

S.  granulata  (E.),  Georgia ;  S.   Am- 
phora (E.),  Palestiae. 


Genus  EXCYOXEMA  (Ktitz.). — Fnistules  cymbiform,  arranged  in  longi- 
tudinal series  within  submembranous  tubular  filaments.  Valves  divided 
unequally  by  median  line  and  nodules.  "  Encyonema  differs  from  Schizo- 
nema  and  other  frondose  genera  of  Diatomaceae  in  the  form  of  its  fnistules, 
a  single  frustule  resembhng  one  of  Cymbella  or  Cocconema.  It  is  more 
probable  that  some  bodies,  which  are  reaUy  congeries  of  the  ova  of  certain 
insects,  will  be  at  first  sight  classed  with  Encyonema  ;  but  these  ova,  although 
cymbiform  and  arranged  in  longitudinal   series,   are   neither  siliceous   nor 

striated The  lateral  surfaces  of  the  frustule,  being  convex,  are  observed 

in  the  front  view,  in  which  also  the  fnistules  are  quadrilateral,  with  two 
puncta  at  each  end.  These  puncta  are  less  easily  discerned  in  the  dorsal 
view,  and  the  dorsum  is  longitudinally  convex.  The  lateral  view  is  semi- 
eUiptic,  with  numerous  transverse  striae,  which  are  interrupted,  as  in  Cocco- 
nema, by  a  longitudinal  pellucid  hue"  (Ralfs).  Professor  Smith  says  that  the 
frustules  of  Encyonema,  even  when  removed  from  the  frond,  may  be  distin- 
guished from  those  of  CymbeUa,  "as  the  terminal  nodules  of  the  median  line 
in  CymbeUa  are  placed  at  the  extremities  of  the  valves,  while  in  Enej^onema 
they  are  removed  to  some  distance  above,  and  occupy  a  place  nearer  the 
central  nodule." 


ExcYONEMApros2;>-«^w;/i  (Berk.,  Ralfs). 
—  Filaments  subsimple  j  valves  with 
rounded,  mostlv  incurved  ends;  strise 
18  in  -001".  Leng-th  -0016"  to  -0024". 
Ealfs,  ANH.  1st  ser.  x\-i.  pi.  3.  f.  3 ; 
KSA.  p.  61;  SD.  ii.  p.  68,  pi.  54.  f.  345! 
=  Momnna  j^^'ostratum,  Berk  BA.  pi.  4. 
f.  3  ;  Schizo)iema  prostratum,  Grev  BFl. 
p.  414 ;  Encyonema  paradoxwn,  E  Inf. 
p.  237 ;  Gloeonema  Leihleini,  Ag  CD. 
p.  31  ?  Em^ope,  Asia,  America.  The 
valves  have  a  depression  beneath  each 
apex ;  sometimes  the  depression  is  very 
slight,  at  others  so  deep  and  notch-like 
that  the  ends  become  rostrate.  The 
former  condition  is  the  E.  imradoxum  of 
Kiitzing.     {xtl.  49  ;  xiv.  22.) 

E.  Auersicaldii  (Rab.). — Valves  with 
ver}^  convex  dorsum,  slightly  gibbous 
venter,  and  contracted,  produced,  obtuse 
ends  ;  striae  11  or  12  in  -001".  Rab  D. 
p.  24,  pi.  7.  f.  2.     Leipzig. 

E.  ccespitosum  (K.). — Filaments  erect, 
tufted,  much  interwovou  ;    valves  with 


convex  dorsum,  slightly  tumid  venter,  and 
straight,  slightlv  produced,  obtuse  ends  ; 
stri«  24  in  -001".  KSA.  p.  61 ;  SBI).  i. 
p.  68,  pi.  55.  f.  346.=^.  jJrostrafitm,  KB. 
p.  82.  Europe.  The  fi'ustules  are 
smaller  than  those  of  E.  2^i'ostratum. 

E.  triangulum  (E.,  K.). — Valves  with 
very  convex,  gibbous  dorsum,  slightly 
convex  venter,  and  produced,  acute 
apices.  KSA.  p.  62.  =  Gl<jeonema  trian- 
gulum, ERBA.  1845,  p.  77  ;  EM.  t.  35  a. 
7.  f.  10.  River  Niagara.  Dorsum  so 
turgid  as  to  give  the  valve  a  ti'iangular 
outline.  "  It  is  a  very  remarkable  cir- 
cumstance, that  I  often  found  two  differ- 
ent sorts  of  frustules  in  the  same  tube 
— one  very  delicate  and  straight  like  a 
Naunema,  the  other  the  large  curved 
kind.  Even  to  the  present  moment  I 
cannot  explain  this  phenomenon ;  for  both 
sorts  were  in  considerable  quantities  and 
quite  free,  and  therefore  it  is  difficult  to 
suppose  one  a  parasite  "  (E.). 

E.    Sinensis    (E.).  —  Valves    oblong, 


880  SYSTEMATIC  HISTOET  OF  THE  INEUSOEIA. 

striated,  with  the  habit  of  Cocconema,  |  middle  and  indistinct    striae.     Rab  D. 

but    suddenly  reflexed  under   the   very  j  p.  26,  pi.  10.  f.  1.     Salzburg.     Frustules 

obtuse  apices  in  the  manner  of  Eunotia.  !  minute. 

=  Glceonema    Sinense,     ERBA.     1847,  I  t\     t  ./•  7  cv      • 

p.  484;  EM.    China,  Java.    Ehrenberg-'s  I  ^    Doubtful  Species. 

figure   represents    the   valve    distinctly  I      E.  globiferiim  (Ag.). — Filaments  ab- 

striated,  with  straight  venter,  very  ob-  |  breviated,  frustules   simple  or  binately 

tuse,  rounded  ends,  and  the  dorsal  mar-  [  conjoined,  hyaline,  with  a  globule  in  the 

gin  very  convex,  and  curved  upwards  at    middle.  =  GlcBonema  glohiferum,  Ag  CD. 

each  end.  |  p.  31.     Italy. 

E.  gracile   (Rab.).  —  Valves  slender,!      'E.  Arcus=  Glceonetna  Arcus,  ERBA. 
with  truncate   apices^   slightly  gibbous  ;  1856,  p.  333,  f.  26.     Africa. 

Genus  AMPHORA  (Ehr.). — Frustules  free,  cymbiform ;  lateral  view  lunate 
or  arcuate,  with  a  nodule  at  the  middle  of  the  ventral  margin ;  front  view 
with  the  median  lines  and  nodules  of  valves  approximate  and  within  the 
margin.     The  frustules  are  mostly  very  thin,  hyaline,  and  imperfectly  sili- 
cious:  their  form  is  peculiar;  and  Professor  Arnott,  who  has  given  in  the 
sixth  volume  of  the  'Microscopic  Journal'  a  detailed  account  of  their  structure, 
aptly  compares  it  to  that  of  "  a  coffee-bean  rounded  on  the  back  and  hollowed 
out  in  front."     Many  of  the  species  are  insufficiently  known  ;  they  should  be 
viewed  in  front,  back,  and  side.     Fortunately,  from  their  hyaline  natui'e,  the 
dorsum  and  venter  can  in  most  cases  be  examined  merely  by  the  alteration  of 
the  focus.     The  lateral  view  closely  resembles  that  of  a  Cymbella,  but  has  the 
nodule  marginal.     The  front  view  is  usually  barrel- shaped,  owing  to  the  con- 
vexity of  the  valves,  which  are  so  curved  inwards  that  their  central  nodules 
are  more  or  less  approximate  and  frequently  appear  nearer  to  the  connecting 
zone  than  to  the  margins.     The  portions  of  the  valves  interior  to  the  median 
line  are  inconspicuous,  and  rarely  afford  diagnostic  aid ;  whilst  the  portions 
exterior  to  the  median  lines  are  important,  offer  the  best  view  of  the  trans- 
verse striae,  and  vary  in  shape  according  as  the  median  line  appears  straight, 
concave,  or  flexed.     In  our  descriptions  we  call  these  latter  the  outer  por- 
tions, and  when  they  project  inwards  at  the  centre  in  a  cuneate  manner,  or 
appear  inflexed,  we  term  them  canoe-shaped.     The  dorsum  is  convex,  shows 
no  nodules  or  lateral  valves,  and  is  mostly  marked  by  longitudinal  lines 
between  longitudinal  series  of  short,  transverse  striae,  like  the  connecting 
zone  of  StriateUa,  but  unaccompanied  by  internal  plates.     The  late   Pro- 
fessor Gregory,  who  directed  attention  to  these  facts,  believed  that  Amphora 
could  be  divided  into  two  groups — simjole  and  complex,  from  the  absence  or 
presence  of  this  structure.     His  arrangement,  however,  we  are  unable  to 
adopt,  because  in  many  species  a  decision  is  difficult ;  and  indeed  we  think 
that  the  longitudinal  lines,  so  common  if  not  invariable,  indicate  the  complex 
structure,  although  the  hyaHne  natiu'e  of  the  frustules  may  interfere  with  its 
detection.     In  ximphora  the  specific  characters  are  taken,  almost  constantly, 
from  the  front  \dew,  and  not  from  the  lateral  one  as  in  most  other  genera  of 
Diatomaceae ;  and  as  the  connecting  zone  varies  greatly  in  breadth  according 
to  the  condition  of  the  frustule,  due  allowance  must  be  made  for  that  fact.    If 
division  has  recently  taken  place,  the  connecting  zone  will  be  narrow,  and  the 
ends  of  the  frustule  less  broadly  truncate  than  just  previous  to  that  process. 
For  the  same  reason  we  believe  that  the  number  of  longitudinal  lines  varies 
and  affords  no  aid  in  distinguishing  the  species.     Amphora  contains  several 
species  of  Agardh's  genus  Cjonbella,  and  ought,  in  our  opinion,  to  have  re- 
tained that  generic  appellation.     Because  of  its  cymbiform  frustules,  we  have 
removed  this  genus  from  the  Naviculeae,  where  Kiitzing  placed  it ;  the  same 
reason,  added  to  the  presence  of  median  lines  and  nodules,  compels  us  to 


OF  THE  CYMBELLE^. 


881 


place  it  with  the  Cymbellese  instead  of  with  the  Surirelleae,  as  Rabenhorst 
has  done. 


*  Fnistides  in  front  view  distinctly 
constricted  at  the  middle. 

Amphora  hinodis  (Greg.). — Fmstiiles 
constricted  at  the  middle  ;  lobes  inflated 
at  the  base^  with  broadly  linear,  sub- 
truncate  ends  ;  transverse  striae  obscm-e, 
about  30  in  -001".  GDC.  p.  38,  pi.  4. 
f.  Q7.  Marine.  Scotland.  Resembles 
the  next  species,  but  is  smaller,  with 
more  rounded  inflations  and  obscure 
striae,  Greg. 

A.  angidans  (Greg.). — Frustules  sinu- 
ato-constricted  at  the  middle ;  lobes  an- 
gularly inflated,  with  .short,  broadly 
linear,  truncate,  produced  ends ;  striae 
distinct.  Greg.  MJ.  iii.  p.  39,  pi.  4.  f.  6. 
(vii.  50.)  Difiers  from  A.  hinodis  by 
having  angular  inflations  and  coarser 
striae. 

A.  lyrata   (Greg.).  —  Frustules   con- 


flated base  and  truncate  end ;  nodules 
transversely  dilated ;  striae  distinct. 
GDC.  p.  48,  pi.  5.  f  82.  Marine.  Scot- 
land. Striae  about  36  in  -001" ;  connect- 
ing zone  with  longitudinal  lines. 

A.  Milcsiana  (Greg.).  —  Frustules 
Hnear,  wdth  slightly  constricted  middle 
and  truncate  ends,  furnished  with  longi- 
tudinal lines  and  conspicuous  transverse 
strire.  GDC.  p.  49,  pi.  5.  f  83.  Scot- 
land.    Striae  about  28  in  -001",  Greg. 

2*  Fnistides  not  pandurifonn ;    nodules 
transversely  dilated  and  bar-like. 

A.  memhranacea  (S.). — Frustules  ellip- 
tic-oblong, with  rounded  ends ;  valves 
with  a  central  transverse  band,  and  very 
close  transverse  stiiae ;  connecting  zone 
with  longitudinal  lines.  SBD.  i.  p.  20, 
pi.  2.  i.  29 ;  Ro  MJ.  vi.  p.  24,  pi.  3.  f  8. 
Brackish  water.  Em'ope.  (vu.  51.) 
Scarcely  silicious. 

A.  Icevissima  (Greg.). — Frustules  very 
hyaline,  linear-oblong,  with  rounded 
ends ;  outer  portions  of  valves  slender, 
tapering,  with  a  transverse  nodule,  and 
obsolete  or  indistinct  striae.  GDC.  p.  41, 
pi.  4.  f  72.     Scotland. 

A.  /(«f/s(Greg.). — Frustules  very  hya- 
line, linear,  with  subtruncate  ends  ;  outer 
portions  of  valves  very  narrow^,  with  a 
transverse  nodule  and  indistinct  striae. 
GDC.  p.  42,  pi.  4.  f  74.  Scotland.  Outer 
portion  of  valve  canoe-shaped  5  striae 
about  60  in  -001 '. 

A.  minutissima  (S.). — Frustules  para- 
sitic, very  minute,  oval  or  suborbicular, 


with  transversely  dilated  nodides,  and 
64  obscure  striae  in  -001".  SBD.  i. 
p.  20,  pi.  2.  f  30.  Fresh  water.  Para- 
sitic on  other  Diatomaceae. 

A.  rimosa(^.y — Germany.  Frustules 
elliptic-oblong,  with  rounded  ends,  nar- 
row lunate  outer  portions,  transverse 
nodules,  and  no  striae.  EM.  pi.  13. 2. 
i.  17. 

A.,  elegans  (Greg.). — Frustules  oval, 
with  truncate  ends ;  outer  portion  of 
valves  lunate,  with  transverse  nodule, 
and  very  fine,  inconspicuous,  transverse 
striaj.  Greg.  TM.  v.  p.  70,  pi.  1.  f  30. 
Scotland. 

A.  ostrearia  (Breb.). — Frustules  hya- 
line, elliptic-oblong,  with  rounded  ends ; 
outer  portion  of  valves  narrow,  canoe- 
shaped,  with  transverse  nodide  and  di- 
stinct striae ;  dorsum  wdth  numerous, 
very  delicate  longitudinal  lines.  Breb. 
in  KSA.  p.  94.  Marine.  France.  Lateral 
view  lunate,  wdth  convex  dorsum  and 
straight  venter. 

A.  quadrata  (Breb.). — Frustules  hya- 
line, quadrangular,  with  truncate  ends ; 
outer  portion  of  valve  smaU,  indexed, 
with  transverse  nodule ;  dorsimi  with 
numerous,  very  delicate  longitudinal 
lines.  KSA.  p.  95.  Marine.  France. 
Lateral  view  very  narrow,  lunate.  A. 
quadrata  difters  from  A.  ostrearia  by  its 
straight  margins  and  truncate  ends. 

A.  rectangularis  (Greg.). — Frustules 
narrow,  linear,  with  truncate  ends ; 
valves  with  a  transverse  nodule,  and  40 
fine  transverse  striae  in  -OOl".  Greg. 
TM.  V.  p.  70,  pi.  1.  f  29.     Scotland. 

A.  nob  His  (Greg.).  —  Frustules  very 
hyaline,  barrel-shaped,  with  truncate 
ends  ',  outer  portion  of  valves  very  nar- 
row, arcuate,  with  transverse  nodule, 
and  fine  transverse  striae;  dorsum  w^ith 
longitudinal  lines.  GDC.  p.  49,  pi.  5. 
f  87.  Scotland.  Large ;  striae  about 
40  in  -OOl";  ventral  margin  of  valves 
concave. 

A.  acuta  (Greg.).  —  Frustules  elliptic, 
with  truncate  ends;  outer  portion  of 
valves  arcuate,  with  straight  median 
line,  transverse  nodide,  and  distinctly 
moniliform,  transverse  striae.  GDC. 
p.  52,  pi.  5,  6.  f  93.  Scotland.  Large ; 
striae  about  36  in  -001". 

A.  litoralis  (Donkin), — Frustules  oval, 
with  truncate  ends  ;  outer  compartment 
canoe-shaped,  with  distinct  moniliform 
striae  and  transverse  bar-like  nodule ; 
dorsum  with  longitudinal  series  of  short 
3l 


882 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


transverse  striae,  Donkin  in  TMS.  vi. 
p.  30;  pi.  3.  f.  15.  Marine.  Northumber- 
land,    (vii.  52.) 

3  *  Frustules  icith  produced  or  rostrate 
ends  and  rowidish  nodules. 

A.  aponina  (K.). — Frustules  lanceo- 
late-elliptic, with  produced,  truncate 
apices,  and  no  longitudinal  lines.  KB. 
p.  108,  pi.  5.  f.  33.  Italy.  Minute. 
1-1080"  to  1-650". 

A.  coffeceformis  (Ag.,  K.). — Frustules 
lanceolate,  with  produced,  obtuse  apices, 
strong-  marginal  longitudinal  lines,  and 
faint  or  obsolete  median  ones.  KB. 
p.  108,  t.  5.  f.  37.  =  Frustulia  coffece- 
f or  mis,  Ag. ;  Naricula  quadricostata,  E 
Inf.  t.  21.  f  9.  /3.  Fischeri,  with  fewer 
marginal  and  obsolete  median  longi- 
tudinal lines.  Carlsbad.  1-1720"  to 
1-480". 

A.  acutiuscula(K.). — Frustules  turgid- 
lanceolate,  with  acuminated,  subacute 
apices,  and  strong  marginal  longitudinal 
lines.  KB.  p.  108,  t.  5.  f  32.  Marine. 
Genoa.     Small.     1-576". 

A.  lineata  (Greg.). — Frustules  eUip tic- 
lanceolate,  with  prolonged  conic  ends 
and  conspicuous  longitudinal  lines ; 
transverse  striae  fine,  obscm^e,  about  42 
in  -001".  GDC.  p.  40,  pi.  4.  f.  70.  Scot- 
land. Outer  portions  of  valves  narrow 
limate,  with  convex  dorsmn  and  straight 
venter. 

A.  Ergadensis  (Greg.).  —  Frustules 
elongated  lanceolate,  with  broad,  slightly 
produced,  truncate  ends;  transverse  striae 
conspicuous,  about  24  in  -001".  GDC. 
p.  40,  pi.  4.  f.  71.  Scotland.  Remarkable 
tor  its  length.  Outer  portions  of  valves 
slender,  with  nearly  straight  venter. 

A.  exigua  (Greg.). — Frustules  elliptic- 
lanceolate,  with  slightly  produced,  ob- 
tuse ends ;  transverse  striae  about  28  in 
•001".  GDC.  p.  42,  pi.  4.  f  J5.  Scotland. 
Small ;  in  size  and  form  it  approaches 
nearest  to  A.  lineata,  but  its  markings 
are  totally  different,  Greg. 

A.  Semen,  EM.  pi.  38.  17.  f  ^  10.  Ice- 
land. In  the  figm-e,  this  species  is  ven- 
tricose,  with  broad,  shortly  produced, 
truncate  ends,  and  without  striae. 

A,  salina  (S.). — Frustules  elliptic-ob- 
long, with  slightly  produced,  trimcate 
extremities;  valves  limate,  rostrate, 
with  64  striae  in  -001".  SBD.  i.  p.  19, 
pi.  30.  f.  251.  Brackish  water.  Sussex. 
Scarcely  silicious.     -0008"  to  -0016",  S. 

A.  turgida  (Greg.). — Frustules  broadly 
elliptic  or  suborbicular,  with  short  ros- 
trate apices  ;  outer  portions  semilunate, 
with    capitate    apices,    and    24    rather 


coarse  radiant  striae  in  '001".  GDC. 
p.  38,  pi.  4.  f  63.     Scotland.     Small. 

A.  monilifera  (Greg.).  —  Frustides 
elliptic-oblong,  with  short,  broad,  ros- 
trate ends ;  outer  portions  arcuate,  with 
capitate,  recm'\'ed  apices;  dorsum  with 
converging  longitudinal  rows  of  distant 
dots.  GDC.  p,  39,  pi.  4.  f  69.    Scotland. 

A.  cymhifera  (Greg.). — Frustules  in- 
flated, with  short,  subcapitate,  rostrate 
apices ;  outer  portions  arcuate,  with 
capitate,  recm-ved  ends,  and  22  rather 
coarse  transverse  striae  in  '001" ;  con- 
necting zone  with  converging  longi- 
tudinal bars.  GDC.  p.  54,  pi.  6.  f  97. 
Scotland.  (^t:i.  54.)  Large ;  dorsum 
fm-nished  with  longitudinal  series  of 
transverse  striae,  separated  by  longi- 
tudinal lines  or  bars. 

A.proboscidea  (G.). — ^Frustules  linear- 
oblong,  with  produced,  truncate  extre- 
mities ;  valves  arcuate,  ^vith  rostrate, 
capitate  ends,  and  20  coarse  transverse 
striae  in  -001" ;  dorsimi  with  longitudinal 
series  of  transverse  striae.  GDC.  p.  54, 
pi.  6.  f.  98.  Scotland.  Large.  The 
capitate  beaks  of  the  valves  are  longer 
than  in  A.  cymhifera,  and  are  not  re- 
cm'ved,  but  bent  foi'wards. 

A.  costata  (S.). — Frustides  ventricose, 
with  short,  broad,  truncate  beaks,  longi- 
tudinally costate  ;  costae  with  a  double 
line  of  moniliform  pimcta.  SBD.  i. 
p.  20,  pi.  30.  f  253.  Marine.  Britain. 
Valves  semilunate,  with  capitate  ends; 
transverse  striae  coarse,  about  16  in 
•001",  Greg. 

A.  Terroris  (E.). — Valves  elongated, 
straight,  semilunate,  suddenly  attenuated 
into  stiliform  beaks ;  transverse  striae 
strongly  granulated,  19  in  1-1200". 
ERBA.  1853,  p.  526 ;  EM.  pi.  35  a.  23. 
£  2.  Akin  to  A.  fasciata,  but  smaller 
and  more  strongly  granulate,  E. 

A.  macilenta  (Greg.). — Frustules  nar- 
row elliptic-lanceolate,  with  short, 
broad,  slightly  produced  apices ;  outer 
portion  of  valves  with  straight  ventral 
margin,  and  about  30,  rather  coarse 
paraUel  stri^  in  -001".  GDC.  p.  38, 
pi.  4.  £  65.     Scotland. 

A.  gramdata  (Greg.).  —  Frustules 
linear-oblong  or  elliptic-oblong,  with 
short,  broad,  truncate,  slightly  produced 
apices;  outer  portion  of  valve  with 
straight  ventral  margin,  rostrate  apices, 
and  from  24  to  30  transverse  sti-iae  in 
•001" ;  dorsum  having  longitudinal  lines 
alternating  with  series  of  granules. 
GDC.  p.  53,  pi.  6.  £  96.     Scotland. 

A.  vetitricosa  (Greg.). — Frustules  lan- 
ceolate, with  turgid  middle  and  tapering 


OP  THE  CYMBELLE^. 


883 


obtuse  ends;  outer  portions  slender, 
arcuate,  with  slightly  concave  renter, 
acute  ends,  and  about  22  conspicuous 
transverse  sti'iae  in  -OOl".  GDC.  p.  39, 
pi.  4.  f.  68.     Scotland. 

4*  Frustules  neither  constricted  at  the 
middle  nor  rostrcde  at  the  ends ;  nodules 
roundish, 

A.  ovaUs  (K.). — Frustides  turgid,  oval, 
with  broadly  rounded  or  truncate  ends  ; 
outer  portion  of  valves  canoe-shaped, 
with  24  distinct  moniliforni  strife  in 
•001"  ;  connecting  zone  wdth  very  fine 
longitudinal  lines.  KB.  p.  107,  t.  5. 
f.  35,  39.  =  Navicula  Amphora,  E  Inf. 
t.  14.  f.  3.  Fresh  water,  frequent.  Eu- 
rope, Afi-ica.  (vn.  56;  IX.  153.)  Large. 
1-456"  to  1-120". 

A.  Lihyca  (E,). — Frustules  oval,  with 
wdth  broadly  rounded  or  truncate  ends  ; 
lateral  view  semilimate,  with  very  con- 
vex dorsimi,  obtuse  ends,  and  slightly 
concave  venter.  EA.  t.  3,  1.  f.  42 ;  EM. 
many  figures.  Apparently  the  most 
common  species,  since  Ehrenberg  gives 
upwards  of  100  habitats  for  it  in  Em^ope, 
Asia,  Africa,  and  America.  Lough 
Mourne  deposit.  (xii.  38.)  We  are 
unable  to  distinguish  this  form  from  A. 
ovalis,  and  probably  these  have  been 
confounded ;  we  believe  they  are  in 
SBD.,  because  there  no  species  but  A. 
oralis  is  noticed  as  occm-ring  in  the 
Lough  Mom-ne  deposit,  whilst  Ehren- 
berg only  mentions  this  species  as  found 
in  it.  Ehrenberg's  figures  and  descrip- 
tion do  not  enable  us  to  decide  ;  for  the 
latter  is  too  indefinite,  and  the  former 
vary  so  much  as  apparently  to  belong  to 
more  than  one  species.  Almost  the  only 
characters  the  figures  have  in  common 
are  the  oval  form  and  striated  valves. 
The  median  line  is  either  concave, 
straight,  or  produced  at  the  nodule  ;  and 
the  connecting  zone  is  figured  sometimes 
smooth,  and  sometimes  with  longitudinal 
lines. 

A.  peUucida  (Greg.). — Frustules  very 
Hyaline,  oval,  with  broadly  rounded 
ends;  outer  portions  of  valves  canoe- 
shaped,  with  about  30  very  delicate  striae 
in  -001".  GDC.  p.  41,  pi.  4.  f.  73.  Scot- 
land. Resembles  A.  ovalis  in  form,  but 
differs  in  its  marine  habitat,  veryhj^aline 
aspect,  and  singular  delicacy  of  the  striae. 
The  latter  characters  distinguish  it  also 
from  A.  incurva,  Greg. 

A.  truncata  (Greg.). — Frustules  barrel- 
shaped,  with  truncate  ends ;  outer  por- 
tions of  valves  canoe-shaped,  striated ; 
dorsum  with  longitudinal  series  of  short 


transverse    striae.      GDC.  p.  43,  pi.  6. 
f.  77.     Scotland.     Large. 

A.  lineolata  (E.).  —  Frustules  tm'gid, 

elliptic-oblong,    wdth    truncate    apices, 

strong  longitudinal   marginal  lines,  and 

!  very  fine  ones  in  the  connecting  zone.  E 

'  Inf.  t.  14.  f.  14;  EM.  pi.  13.  1.  f.  19 ;  Rab 

!  D.  pi.  9.  f.  9, 10.     Fresh  water.     Europe, 

I  Africa,  America.    1-480"  to  1-140".    The 

I  figm'es  referred  to  represent  the  frustule 

I  as    large,   barrel-shaped,    wdth    canoe- 

j  shaped  outer  portions. 

I      A.  Grec/orii. — Frustules  barrel-shaped; 

outer  portions  canoe-shaped,  with  about 

34  transverse  striae  in  -001" ;  dorsum wdth 

longitudinal  series    of    short  transverse 

striae.  =^.  quadrata,  GDC.  p.  49,  pi.  6. 

f.  85.     Scotland.     Ends  trimcate. 

A.  Grecilliana  (Greg.).  —  Frustules 
broad,  linear,  oblong  or  barrel-shaped; 
outer  portions  canoe-shaped,  with  from 
28  to  34  distinct,  moniliforni  transverse 
striae  in  -001"  ;  dorsum  with  longitudinal 
series  of  transverse  striae.  GTM.  v.  pi.  1. 
f.  36  ;  GDC.  p.  50,  pi.  5.  f.  89.  =  ^.  com- 
plexa,  GDC.  p.  51,  pi.  5.  f  90 ;  A.  fasciata, 
GDC.  p.  51,  pi.  5.  f.  91.  Scotland."  Large ; 
ends  trimcate. 

A.  sulcata  (Breb.). — Frustules  hyaline, 
oblong  or  elliptic-oblong,  wdth  trimcate 
ends  ;  outer  portions  canoe-shaped,  with 
38  transverse  striae  in  -001" ;  dorsum 
with  longitudinal  series  of  transverse 
striae.  BD.  pi.  18.  f.  8 ;  GDC.  p.  51, 
pi.  5.  f.  92.  France,  Britain.  Large ; 
differs  from  A.  costata  in  its  not  produced 
but  truncate  apices,  Breb. 

A.  rohusta  (Greg.). — Frustules  broadly 
oval,  with  rounded  ends  and  canoe- 
shaped  outer  portions ;  transverse  striae 
distinct,  moniliforni,  16  in  -001".  GDC. 
p.  44,  pi.  5.  f.  79.  Scotland.  Large ; 
conspicuous  from  its  size  and  stoutness. 

A.  Proteus  (Greg.). — Frustules  barrel- 
shaped  or  oblong ;  outer  portions  canoe- 
shaped,  wdth  22  finely  moniliforni  trans- 
verse stri^  in  -001".  GDC.  p.  46,  pL  5. 
f.  81.  Scotland.  Large,  with  truncate 
apices.  Varies  much  in  form  and  length. 
A.  Arcus  (Greg.). — Frustules  barrel- 
shaped;  outer  portions  narrow,  canoe- 
shaped,  with  16  to  18  coarsely  monili- 
form  striae  in  -001" ;  dorsum  wath  longi- 
tudinal series  of  moniliform  transverse 
stria3.  GMJ.  iii.  pi.  4.  f.  4 ;  TM.  v.  pi.  1. 
f.  37  ;  GDC.  p.  50,  pi.  5.  f.  88.  Scotland. 
Large,  with  truncate  ends.  The  frustule 
has  the  form  of  a  barrel,  with  ribs  and 
bars.  It  is  distinguished  from  A.  Gre- 
villiana  by  its  coarsely  moniliform  striae. 
Detached  segments  resemble  in  form  a 
strung  bow  wdth  rostrate  apices. 
3l2 


884 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


A.  veneta  (K.).  —  Friistiiles  minute, 
elliptic-oblong-,  with  truncate  ends ; 
lateral  view  semielliptic.  KB.  p.  108, 
t.  3.  f.  25.  Marine.  Venice  and  Con- 
stantinople. 

A.  horealis  (K.). — Frustules  minute, 
oblong-lanceolate,  with  acute  or  trun- 
cate apices ;  lateral  view  semilanceolate. 
KB.  p.  108,  pi.  3.  f.  18.  Heligoland. 
1-1200". 

A.  Holienackeri  (Rab.).  —  Frustules 
minute,  oblong  or  oblong-lanceolate, 
with  three  longitudinal  lines  on  each 
side.  Rab  D.  p.  31,  pi.  9.  f.  11.  South 
Persia. 

A.  hyalina  (K.). — Frustules  hyaline, 
elliptic-lanceolate,  with  acute  or  trun- 
cate apices,  and  a  few,  very  delicate 
longitudinal  lines ;  transverse  strise  ob- 
scm-e.  KB.  p.  108,  pi.  30.  f.  18;  SBD. 
i.  p.  19,  pi.  2.  f.  28.  Marine.  Europe, 
(vii.  58.)  Imperfectly  silicious.  1-600" 
to  1-422". 

A.  nana  (Greg.).  —  Frustules  small, 
narrow  elliptic-oblong,  with  rounded 
ends  ;  outer  portions  with  straight  ven- 
tral margin,  and  about  50  transverse 
strife  in  -001".  GDC.  p.  38,  pi.  4.  f.  64. 
Scotland. 

A.  elUptica  (Ag.,  K.).  —  Frustules 
small,  elliptic-lanceolate,  turgid  at  the 
middle,  with  attenuated  obtuse  apices ; 
valves  distinctlv  striated.  KB.  p.  108, 
t.  5.  f.  31.  =  CijmheUa  elUptica,  AD.  p.  8. 
Marine.  Baltic.  Associated  in  amor- 
phous mucus,  K. 

A.  navicidaris  (E.). — Frustules  ellip- 
tic-lanceolate, with  subacute  ends  and 
conspicuous  transverse  striae.  EA.  p.  122, 
t.  1. 1.  f.  12.    Africa,  America,    (xii.  37.) 

A.  gracilis  (E.). — Frustules  small,  nar- 
row oblong,  truncate;  valves  slender, 
transversely  striated.  EA.  t.  3.  1.  f.  43 ; 
EM.  t.  37.  3.  f.  1.  Europe,  Asia,  Africa, 
America,  Australia,  (xii.  26.)  Outer 
portion  of  valve  lunate. 

A.  affinis  (K,).  —  Frustules  oblong, 
slightly  attenuated,  with  rounded  or 
broadly  truncate  apices,  marked  with 
longitudinal  lines,  the  central  ones  very 
faint.  KB.  p.  107,  t.  30.  f.  m.  France, 
Britain.     1-960"  to  1-390". 

A.  marina  (S,). —  Frustules  elliptic, 
with  somewhat  trimcate  extremities; 
nodule  very  faint;  striae  40  in  -001". 
ANH.  1857,  xix.  p.  7,  pi.  1.  f.  2.  Marine. 
France,  Britain.  -0006"  to  -0024'. 
(vii.  59.)  Not  unfrequent,  but  has  been 
overlooked  from  its  exact  resemblance  in 
outline  to  A.  affinis ;  it  may  be  known 
by  its  more  delicate  striae  and  inconspi- 
cuous nodules,  Sm. 


A.  duhia  (Greg.). — Frustules  oblong, 
with  broadly  rounded  ends ;  outer  por- 
tions stout,  with  concave  venter,  obtuse 
ends,  and  24  fine  transverse  striae  in 
•001".  GDC.  p.  42,  pi.  5.  f.  76.  Scot- 
land. It  has  some  analogy  with  A. 
inarina ;  but  the  striation  is  coarser,  and 
nodides  distinct,  Greg. 

A.  ohlonga  (Greg.). — Frustides  elon- 
gated linear-oblong  or  elliptic-oblong, 
with  conic  apices  ;  outer  portions  very 
narrow,  canoe-shaped,  with  conspicuous 
nodule,  and  24  distinct  transverse  striae 
in  -001".  GDC.  p.  43,  pi.  5.  f.  78. 
Scotland.     Large. 

A.  elongata  (Greg.). — Frustules  elon- 
gated, narrow,  oblong-lanceolate,  trun- 
cate ;  outer  portions  very  narrow,  canoe- 
shaped,  wath  26  conspicuous  transverse 
striae  in  -001";  dorsum  with  longitudinal 
lines.  GDC.  p.  49,  pi.  5.  f.  84.  Scotland. 
Large. 

A.  angusta  (Greg.). — Frustules  nar- 
row linear-oblong,  truncate;  outer  por- 
tions with  44  fine  transverse  striae  in 
•001".  GDC.  p.  38,  pi.  4.  f.  66.  Scot- 
land. 

A.  obtusa  (Greg.).  —  Frustules  broad 
linear-oblong,  with  broadly  rounded 
ends  ;  outer  portions  canoe-shaped,  with 
70  verv  fine  transverse  striae  in  -001". 
Greg.  TM.  v.  pi.  1.  f.  34.  Scotland. 
Large. 

A.plicata  (Greg.). — Frustules  hyaline, 
broad  linear-oblong,  with  rounded  an- 
gles and  truncate  apices ;  outer  portion 
canoe-shaped,  very  faintly  striated; 
dorsmn  with  longitudinal  lines.  Greg. 
TM.  V.  pl.^  1.  f.  31.  Scotland.  Large. 
The  longitudinal  lines  give  a  plicate 
appearance  to  the  frustule,  Greg. 

A.  crassa  (Greg.). — Frustules  linear 
or  linear-oblong,  with  roimded  or  sub- 
truncate  apices;  outer  portions  canoe- 
shaped,  with  from  12  to  20  coarse  trans- 
verse striae  in  -001";  dorsmn  with  longi- 
tudinal series  of  transverse  striae.  GDC. 
p.  52,  pi.  6.  f.  94.  =A.  sulcata,  Ro.  MJ. 
vi.  p.  18,  pi.  3.  f.  7  ?.     Britain.     Large. 

A.  spectabilis  (Greg.).  —  Frustules 
broad  linear  or  linear-oblong,  with 
rounded  angles  and  subtruncate  apices ; 
outer  portions  canoe-shaped,  with  14  to 
16  distinct  transverse  striae  in  -001"; 
dorsum  with  longitudinal  series  of  trans- 
verse stria?.  GDC.  p.  44,  pi.  5.  f.  80. 
Scotland,     (vii.  57.)     Large. 

A.  excisa  (Greg.). — Frustules  h^^aline, 
broadly  linear  or  linear-oblong,  truncate ; 
appearing  notched  at  the  sides  from  the 
marginal  position  of  the  nodides;  outer 
portion  canoe-shaped,  with  52  very  fine 


OF  THE  CYMBELLE^. 


885 


transverse  striae  in  -001" ;  dorsum  with 
longitudinal  series  of  short  strine.  GDC. 
p.  49,  pi.  5.  f.  86.     Scotland. 

A.  arenaria  (Donkin). — Frustules  hj^a- 
line,  broadly  linear,  with  rounded  angles 
and  slightly  gibbous  middle ;  outer  com- 
partment of  valves  canoe-shaped;  dorsum 
faintly  marked  with  longitudinal  lines. 
Donkin,  TMS.  vi.  p.  31,  pi.  3.  f.  16. 
Marine.  Northimiberland.  Large;  trans- 
verse striae  obscm-e. 

A.  ampkioxys  (Bailey).  —  Frustules 
linear,  with  subtruncate  apices ;  lateral 
view  arcuate,  finely  striated,  with  convex 
dorsum,  concave  venter,  and  rostellate 
recurved  extremities.  BMO.  p.  39,  pi.  2. 
f.  20-22.  United  States.  The  side  view 
bears  a  striking  resemblance  to  Eunotia 
amphioxijs,  Bailey. 

A.  hiseriata  (Greg.). — Frustules  elon- 
gated linear,  with  rounded  apices  ; 
median  line  marginal,  except  at  the 
centre,  where  it  curves  inwards ;  dorsum 
with  longitudinal  series  of  coarse  trans- 
verse striae.  Greg.  TM.  v.  p.  71,  pi.  1. 
f.  32.     Scotland.     Large, 

A.  tenera  (S.).  —  Frustides  narrow 
linear,  with  roimded  or  truncate  ends ; 
valve  longitudinally  rugose ;  striae  ob- 
scure, 62  in  -001".  SBD.  i.  p.  20,  pi.  30. 
f.  252.  Marine.  England.  Scarcely 
silicious.  Professor  Smith  regarded  this 
species  as  the  ^4.  lineolata,  E., — an  opinion 
in  which  we  are  unable  to  concur,  since 
its  narrow-linear  form  is  very  unlike  the 
broad  inflated  figm-e  of  the  latter,  and 
could  never  be  described  as  turgid. 

A.  hacillaris  (Greg.). — Frustules  nar- 
row linear,  with  slightly  attenuated,  ob- 
tuse ends,  outer  portions  very  narrow, 
arcuate,  finely  striated;  dorsum  with 
longitudinal  series  of  granides.  GDC. 
p.  55,  pi.  6.  f.  100.  Scotland.  Distin- 
guished from  A.  pusilla  by  its  finer  striae 
and  g-ranules,  Greg. 

A.  pusilla  (Greg.). — Frustules  narrow 
linear,  with  subtruncate  apices ;  outer 
portions  very  narrow,  canoe-shaped, 
with  24  conspicuous  striae  in  -001" ; 
dorsum  with  longitudinal  series  of  gra- 
nules or  short  striae.  GDC.  p.  53,  pi.  6. 
f.  95.     Scotland. 

A.  Ercbi  (E.). — Lateral  view  arcuate, 
with  obtuse  apices,  concave  venter,  and 


about  25  very  fine  striae  in  1-1200". 
ERBA.  1853,  p.  526 ;  EM.  pi.  35  a.  23. 
f.  3.     Assistance  Bay,  North  Pole. 

A.  crystaUma(^.). — Frustides  smooth, 
crystalline,  with  convex  dorsum,  concave 
venter,  and  broadlv  truncate  ends. 
ERBA.  1840,  p.  10.   'Tjorn.     1-432". 

A.fasciata  (E.). — Frustules  with  con- 
vex dorsum,  plane  venter,  broadly  trun- 
cate ends,  and  longitudinal  series  of 
closely  set,  fine  striae.  ERBA.  1840, 
p.  11.     Tjorn.     1-456". 

A.  carinata  (E,). — Frustules  large, 
navicular,  with  plane  sides,  acute  apices, 
and  four  lateral  sti-iated  fasciae.  ERBA. 
1840,  p.  10.     Island  of  Tjorn.     1-240". 

A.  Atomus  (E.).  — Very  minute,  on 
one  side  elliptic  with  rounded  ends,  on 
the  other  linear  and  trimcate.     1-2640". 

A.  JEgcea  (E.). — Frustules  navicular, 
oblong,  truncate,  with  10  punctated 
longitudinal  lines,  oblong  umbilici,  and 
cm-ved  lines;  the  space  between  the 
umbilici  Vvdthi  two  straight  lines  curved 
at  each  end.  ERBA.  1858,  p.  13. 
^Egean  Sea. 

A.  stauroptera  (Bailey).  —  Frustules 
elliptical,  elongated,  ^dth  striated  mar- 
gins ;  central  portions  crossed,  as  in 
Staiu-optera,  by  a  broad  band.  BC.  vii. 
p.  8,  f.  14, 15.  Halifax,  Nova  Scotia.  The 
figure  is  elongated,  acutely  lanceolate, 
and  the  nodules  connected  by  a  trans- 
verse central  depression. 

Species,  the  descriptions  of  which  are 
unknown  to  us. 

A.  cymhiformis,  EM.  pi.  16.  1.  f.  48. 

Lateral  view  semilunate,  with  convex 
dorsum,  straight  venter,  obtuse  apices, 
diverging  striae,  and  submarginal  sutural 
line  and  nodule. 

A.  gigas,^  EM.  pi.  6.  2.  f.  13.  North 
Africa.  Figm'e  imperfect,  large,  oval, 
transversely  striated ;  connecting  zone 
with  faint  longitudinal  lines. 

A.  incurva,  Greg.  MJ.  iii.  pi.  4.  f.  5. 
Scotland.  Lateral  portion  canoe-shaped 
and  finely  striated. 

A.  paradoxa  (E.),  A.  vulgaris  (E.), 
Asia ;  A.  Nilotica  (E.),  River  Nile ;  A. 
ocellata  (E.),  Florida. 


Genus  RHIZONOTIA  (E.). — Frustules  with  two  median  nodules  (with 
the  character  and  form  of  Amphora),  but  by  longitudinal  division  often 
becoming  a  mass  united  together  in  a  longitudinal  series  by  a  progeny  of 
stolons  or  silicious  radicles.  This  form  is  adnate  on  Confervae,  and  has  many 
fine  longitudinal  strise,  which  appear  somewhat  rough  or  granular.     The 


886 


SYSTEMATIC  HISTOKY  OF  THE  INTUSORIA. 


frustule  is  very  crystalline  and  transparent.     It  has  internally  pale-green, 
almost  colourless  ova,  E. 

Rhizonotia  Meh  (E.).— The  lateral  Mdo,  EM.  pi.  35.  6.  f.  14,  15  ?.     Swan, 

connecting  portions  of  the  progeny  in  Avon,  and  Canning  Rivers  in  Western 

self-division    mostly    forked,   3  to    10.  Australia.     (\^n.  41.) 
ERBA.    1843,    p.    139.  =  Rhizosolmia 


EAMILY  XYII.— GOMPHONEME.^. 

Erustules  in  front  view  cuneate,  laterally  attenuated  at  the  base,  with  a 
median  longitudinal  line  and  a  central  nodule.  Mostly  aquatic.  The  Gom- 
phonemeae  differ  from  the  Meridiese  and  the  Licmophoreae,  and  the  cuneate 
species  of  SurireUa,  by  the  median  longitudinal  line  and  the  central  nodule. 
The  cuneate  form  in  the  front  view  distinguishes  it  from  the  rest  of  the 
Diatomacese. 

Genus  SPHENELLA  (K.). — Erustules  in  front  view  cuneate,  free,  neither 
stipitate,  affixed,  nor  enclosed  in  a  common  gelatinous  substance.  Aquatic. 
''  The  SpheneUae  only  diifer  from  Naviculae  in  their  cuneate  form,  perfectly 
similar  to  that  of  Meridion,  by  which,  too,  the  associations  {S.  angustata) 
become  flabeUiform  and  quasi-circular ;  but  they  differ  by  the  central  nodule 
of  the  lateral  surfaces.  Hence  there  remains  a  greater  simihtude  to  the 
Naviculae ;  and  the  distinctive  characters  are  so  slight,  that  the  generic 
characters  of  at  least  two  species  remain  uncertain  "  (Menegh.  p.  411). 


Sphenella  glacialis  (K.). — Minute; 
lateral  view  lanceolate,  with  subacute 
ends  and  very  delicate  transverse  striae. 
I^.  p.  83,  pi  3.  f.  16.  Monte  Rosa, 
Alps.     1-1320". 

S.  imrvula  (K.). — Minute :  lateral  view 
lanceolate,  with  produced  ends,  the  base 
subdilated.  KB.  p.  83,  pi.  30.  f.  63. 
France.  1-960".  Striae  indistinct.  It 
cannot  be  distinguished  from  a  Navicula, 
except  on  a  fi-ont  view. 

S.  angustata  (K.). — Minute,  flabel- 
lately  conjoined,  narrow  linear,  cuneate, 
lateral  view  lanceolate,  with  obtuse 
ends.  KB.  p.  83,  pi.  8.  f.  4.  Germany, 
France,    (xiv.  30.)     1-960". 

S.  vulgaris  (K.). — Small;  lateral  view 
finely  striated,  dilated  at  the  middle, 
and  ^  tapering    to   the    stout    beak-like 


ends.  KB.  p.  83,  pi.  7.  f.  12.  Germany, 
France.     1-1020". 

S.  ohtusata  (K.).  —  Small  ;  lateral 
view  smooth,  dilated  above  the  middle, 
with  roimded  obtuse  apices.  KB.  p.  83. 
pl.9.  f.  1.  Prussia,  (xiv.  31.)  1-900". 
Lateral  view  clavate-lanceolate. 

S.  rostellata  (K.).  —  Solitary,  smooth, 
broadly  cuneate ;  lateral  view  dilated  at 
the  middle,  acuminate  at  each  end.  KB. 
p.  83,  pi.  9.  f.  3.  /3.  elongata,  larger, 
with  produced,  obtuse  apices.  France. 
1-1820"  to  1-336". 

S.  ?  Italica  (K.).  —  Broadly  cuneate ; 
lateral  view  obovate,  slightly  dilated  at 
the  middle,  and  with  a  transverse  me- 
dian nodule.  KSA.  p.  63.  =  Gompho- 
nema  Italicum,  KB.  t.  30.  f.  75. 


Genus  GOMPHONEMA  (Ag.). — Erustules  affixed  at  the  base  or  stipitate ; 
in  front  ^dew  cimeate  ;  laterally  attenuated  below,  with  a  median  longitudinal 
line  and  central  nodule.  "  As  Cocconema  from  Cymbella,  so  Gomphonema 
only  differs  from  Sphenella  by  the  stipes,  on  which  account  species  are  now 
referred  to  Gomphonema  which  formerly  belonged  to  Sphenella.  .  .  .  Kiitzing 
supposes  the  Gomphonemae  to  be  at  first  free,  like  Sphenella,  and  that  after- 
wards they  affix  themselves.  ...  No  direct  observation  confirms  this  hypo- 
thesis ;  and  it  is  at  least  as  just  to  admit  the  other,  that  the  Sphenellae  are  at 
first  attached  like  the  Gomphonemae  and  afterwards  become  free.  Ehrenberg 
says  that  the  Gomphonemae  can  become  free  and  again  adhere"  (Menegh. 
p.  412).     The  descriptions  apply  to  the  lateral  view,  unless  otherwise  stated. 


or  THE  GOMPHONEME^. 


887 


*  Frustules  in  lateral  view  constricted  be- 
neath the  apex,  appearing  urn-shaped. 

t  Lateral  view  with  tlie  head  apiculate 
or  acute. 

GoMPHONEMA  coronatum  (E.). — Slen- 
der, with  ventricose  middle,  obcordate 
apiculate  head,  and  lanceolate  base ;  front 
view  crested  at  apex.  EM.  pi.  6.  1.  f.  33. 
=  G.  acuminatum  jS,  SBD.  i.  p.  79,  pi.  28. 
f.  238  /3.  Eiu-ope,  America,  Asia,  Aus- 
tralia, (xiv.  36.)  G.  coronatum  is  di- 
stingTiished  from  the  allied  forms  by  its 
inflated  basal  portion;  but  the  lower 
inflation  is  sometimes  very  obscure,  and 
we  believe  Professor  Smith  was  justitied 
in  regarding  this  form  as  a  mere  variety 
of  G.  acuminatum.     1-480". 

G.  laticeps  (E.). — Habit  of  G.  corona- 
tum, but  shorter,  and  head  wider  than 
the  central  inflation.  EM.  pi.  5.  1.  f.  34. 
America,  Asia.  Ehrenberg's  figm^es  have 
the  basal  portion  linear,  not  inflated. 
He  gives  about  fifteen  habitats. 

G.  Sceptrum  (Rab.).  —  Habit  of  G. 
coronatum,  but  larger  and  more  robust, 
the  middle  more  inflated  and  much 
broader  than  the  obcordate  apiculated 
head ;  base  stalk-like,  not  inflated.  RabD. 
p.  60,  pi.  8.  f.  8.     America. 

G.  aciwiitiatuni  (E.).  —  Slender,  taper- 
ing below  into  the  stalk-like  base,  con- 
stricted above  the  ventricose  middle ; 
head  dilated,  acuminate.  SBD.  i.  p.  79, 
pi.  28.  f.  238.  =  G.  trigo7iocephalum,  EM. 
pi.  6. 1.  f.  36  j  G.  appendiculata,  Perty  KL. 
p.  204,  t.  17.  f.  12.  Europe,  Asia,  Africa, 
America,  and  Australia,  (xin.23.)  Differs 
from  the  foregoing  species  by  a  cuneate 
or  tapering  apex.  In  a  variety  figured 
by  Professor  Smith  the  constriction  is 
nearly  obsolete.     1-860"  to  1-430". 

G.  Brehissonii  (K.). — Slender,  narrow, 
•with  a  longly  attenuated  base  and  a 
slightly  ventricose  middle^  separated  by 
a  slight  constriction  from  the  cimeate, 
attenuated,  somewhat  obtuse  head.  KSA. 
p.  66.  France.  Stipes  abbreviated  or 
nearly  obsolete.  Akin  to  G.  acumina- 
tum, but  more  slender,  more  elongated 
into  the  stipes-like  base,  and  head  and 
median  inflation  smaller. 

G.  Americanum  (E.).  —  Lateral  view 
with  three  inflations,  separated  by  two 
constrictions ;  head  ovate,  subacute. 
EM.  several  figui-es.  America,  Iceland. 
1-864". 

G.  elongatum  (S.). — Lateral  view  \\dth 
three  inflations,  the  median  one  greatest ; 
upper  one  oblong,  with  cimeate  apex ; 
lower  slender,  slight.  S.  in  ANH.  2  ser. 
XV.  p.  6,  pi.  1.  f.  4.=  G.  Brehissonii,  Greg. 


MJ.  ii.  pi.  4.  f.  18.  France,  England. 
1-864".  Scarcely  distinct  from  G.  Ame- 
ricanum ',  both  have  the  inflated  base  of 
G.  coronatum,  and  cuneate  head  of  G. 
acuminatum. 

2 1  Head  rounded,  neither  acute  nor 
apiculate. 

G.  geminatum  (A.).  —  Frustides  very 
large,  in  front  view  cuneate,  their  ter- 
minal pimcta  obsolete ;  lateral  view  in- 
flated at  the  middle,  constricted  above 
and  below,  with  dilated,  rounded  ends ; 
striae  distinctly  moniliform.  SBD.  p.  78, 
pi.  27.  f.  2'3o.=Dio?nphaIa  ClavaHercidis, 
EM.  pi.  15  a.  f.  93.  (vii.  60.)  On  rocks 
in  subalpine  streams.  Em-ope.  This 
species  forms  large  spongy  cushion-like 
tufts  composed  of  densely  matted  fila- 
ments. The  frustules  are  easily  recog- 
nized by  their  large  size,  the  absence  of 
terminal  puncta  in  the  front  view,  and 
the  conspicuous  striae  of  their  lateral 
valves.  The  neck  is  much  constricted, 
and  the  large  head  broadly  rounded  at 
the  end.  Kiitzing  refers  G.  Herculeanum 
(E.)  to  this  species,  but,  we  believe, 
erroneously. 

G.  capitatum  (E.). — Lateral  view  tur- 
gid at  the  middle  and  slightly  con- 
stricted beneath  the  broadly  rounded 
head ;  puncta  in  front  view  evident. 
SBD.  p.  80,  pi.  28.  f.  237.  =  6^.  turgidum, 
EM.  pi.  2.  2.  f.  40 P  Europe,  Asia.  1-1720" 
to  1-280".  Striated,  attenuated  at  its 
base  ;  stipes  elongated,  dichotomous. 
Sometimes  the  constriction,  which  is 
less  marked  than  that  of  the  next  spe- 
cies, is  nearly  obsolete,  and  the  fi'ustules 
in  the  lateral  view  are  obovate. 

G.  constrictum  (E.).  —  Enteral  view 
ventricose  at  the  middle,  with  a  short 
neck  and  broadly  roimded  head ;  puncta 
at  upper  end  of  front  view  very  evident. 
SBD.  pi.  28.  f.  236.  =  6^.  trunccdum,  EM. 
many  figiu'es ;  G.  paradoxum,  EM.  pi.  9. 1. 
f.  33,  34 ;  G.  pohliceforme,  K.,  Ralfs. 
Forms  a  brown  discoloration  on  aquatic 
plants.  Common,  (x.  187-190.)  1-1720" 
to  1-280" ;  striated,  attenuated  at  its 
base ;  stipes  becoming  elongated  and 
branched.  Distinguished  from  G.  gemi- 
ncdmn  by  its  much  smaller  size  and 
distinct  puncta  in  front  view.  We  find 
this  species  very  variable  in  the  develop- 
ment of  its  neck;  and  sometimes  in  a 
yoimg  state  the  constriction  is  but  slight, 
and  the  form  resembles  G.  capitatum. 

G.  sid)tile  (E.). — Slender,  lateral  view 
twice  constricted  5  head  small,  obtuse ; 
neck  slender,  elongated.  EM.  several 
figures.     Asia,  Africa,  America,  Lough 


888 


SYSTEMATIC  HISTOEY  OF  THE  INFrSORIA. 


Moiirne  deposit.  It  differs  from  G.  con- 
strictinn  in  its  more  slender  form  and 
longer  neck. 

O.AnylicumCEi.). — Twice  constricted ; 
bead  rounded,  rather  narrower  tliau  the 
oblong  inflated  middle,  w^hicli  tapers 
below  into  a  linear  stipes-like  base.  EM. 
pl.  15  A.  f.  86.  Lough  Mourne  deposit, 
Ireland.  It  is  allied  to  G.  suhtU-e.  Pro- 
bably both  forms  shoidd  be  united  to 
G.  constn'cftan. 

G.  3lHsfeIa,  EM.  pl.  17.  2.  f.  37.  Fossil, 
Finland,  France;  recent,  Berlin.  We 
have  seen  no  description  of  this  species. 
Ehrenberg's  figures  represent  the  lateral 
view  elongated,  with  an  oblong  median 
inflation,  tapering  below  into  a  linear 
stipes-like  base,  and  above  into  the  ob- 
long head,  which  is  rounded  at  the  apex. 

2*  Friistules  imbedded  in  a  shapeless  gela- 
tinous substance.  (Gomphonella,  Rah.) 

G.  oUvaceum  (Lj^ngb.,  E.). — Frustides 
and  stipes  forming  a  gelatinous  mass; 
front  view  broadly  cimeate,  with  con- 
spicuous terminal  puncta ;  lateral  valves 
obovate  or  subclavate,  distinctlv  stri- 
ated. SBD.  pl.  29.  f.  244.  =  Gomphonella 
olivaceum,  Rab.,  j8.  atiqusta;  G.  angusta, 
K. ;  G.  angusta,  Eab  t).  p.  61,  t.  9.  £  2. 
Smaller  and  shorter,  with  obsolete  stride. 
Europe.  1-2300"  to  1-1020".  It  forms 
rather  large  mucous  masses  of  a  pale 
brown  colour,  which,  when  dried,  be- 
come pale  gTeen  with  a  granulated 
appearance. 

G.  Lenormandi  (Chauvin).  —  Front 
view  narrow,  nearly  linear  ;  lateral 
valves  lanceolate  acute,  with  indistinct 
stripe.  KSx\.  p.  65.  =  Sphenella  ?  Lenor- 
mandi, KB.  pl.  30.  f.  61 ;  Gomphonella 
Lenormandi.,  Rab.  Falaise^  France. 
1-960".  Stipes  slender^  at  length  elon- 
gated. 

Qi.  parvulum  (K.).  —  Frustules  of  the 
size  and  form  of  Spheriella  parvula,  but 
stipitate  and  aggregated  into  a  dense 
mucous  stratum.  KSA.  p.  65.  =  Gom- 
phonella parimla,  Rab. 

3  *  Frustules  in  front  view  curved,  with 
tivo  longitudinal  sutwe-like  lines  or 
vittce. 

G.  curvatum  (K.). — Frustides  in  front 
view  cm^ved,  with  distinct  terminal 
puncta  and  longitudinal  vittae ;  lateral 
valves  clavate.  KB.  p.  85,  pl.  8.  f.  1-3. 
=  G.  minutissimum,  E.  Common.  Eu- 
rope, Asia,  Africa,  America,  (xii.  9-12 ; 
XIII.  11.)  a,  aquatic,  =  G.  curvatum, 
SBD. ;    /3,  marine,  =  G.  marinwn,  SBD. 


This  species  differs  considerably  from 
the  other  species  of  Gomphonema  in  its 
curved  fi-ustules  and  longitudinal  sutm*e- 
like  strife,  and  perhaps  ought  to  be  sepa- 
rated from  them.  It  agrees  with  Rhi- 
pidophora  in  the  latter  character  and 
with  Achnanthes  in  having  a  median 
nodide  in  the  ventral  or  concave  valve 
only.  It  varies  in  its  mode  of  growth, 
according  as  it  is  fomid  in  fresh,  brack- 
ish, saline,  or  marine  waters.  The  frus- 
tules are  scattered,  flabellateiy  conjoined, 
or  aggregated  in  minute  cushion-like 
tufts.  The  stipes  is  short,  incrassated, 
and  irregidarly  branched,  or  more  or  less 
elongated,  slender,  and  dichotomously 
divided.  Professor  Smith  makes  the 
marine  fonn  a  distinct  species,  and  gives 
the  following  differential  characters : — 
G.  curvatum :  "  Stipes  elongated,  fila- 
mentous and  dichotomous ;  stri«  22  to 
30  in  -001'"  ;  aquatic."  G.  marinum  : 
''  Stipes  incrassated,  branching  in  an 
irreo-ular  manner;  striae  35  in  -001"'; 
marine."  Professor  Smith,  however, 
admits  that  it  is  difficidt  to  distinguish 
them  if  we  confine  our  attention  merely 
to  the  frustules;  "but,"  continues  he, 
"the  general  appearance  of  the  gTowing 
plants,  arising  from  the  characters  of 
their  stipes,  is  very  different,  and  their 
habitats  are  so  wide  apart  that  there  can 
be  no  doubt  of  their  distinctness."  We 
are  unable  to  concur  in  this  opinion ;  for 
our  experience  is  quite  different,  and,  as 
we  stated  several  years  ago,  we  find  the 
stipes  in  the  marine  form  more  elon- 
gated than  in  the  aquatic  one.  "  I  have 
attempted  in  vain  to  find  some  specific 
character  to  distingTiish  the  marine  form. 
It  is  more  branched,  has  a  rigid  appear- 
ance, and  the  striae  connecting  the  puncta 
on  the  front  surface  are  strongly  marked ; 
but  intermediate  specimens  occasionally 
occur,  in  which  all  these  differences 
vanish  "  (ANH.  xii.). 

4  *  Frustules  in  lateral  view  ohovate  or 
clavate. 

t  Crested  or  pointed  at  the  apex. 

G.  cristatum  (Ra.). — Frontview  crested; 
lateral  view  obovate,  crow^ned  with  a 
minute  point.  SBD.  p.  79,  pl.  28.  f.  239. 
=  G.  nasutum,  EM.  pl.  2.  2.  f.  41 ;  Sphe- 
nella ?  appendiculata,  Perty,  p.  203,  1. 17. 
f.  14.  Europe,  Asia,  America.  Stipes 
nearly  simple;  frustides  in  front  Adew 
cimeate,  with  somewhat  rounded  angles, 
crested  as  in  G.  coronatum;  terminal 
puncta  obsolete.  Ehrenberg  describes 
his   G,  nasuium  as  allied  to   G.  Augur, 


OF  TRE  GOMPHOKEMEJ::. 


889^ 


but  shorter  and  stouter.  To  G.  cristatum 
probably  belongs  the  Mexican  form  de- 
scribed by  Ehrenberg  as  a  variety  of 
G.  Auc/iir,  having  the  apex  constricted 
into  a  small  terminal  mucro, 

G.  Aiujur  (E.). — Front  view  linear- 
cuneate,  lateral  view  rhomboid,  with 
subacute  apex  and  acuminated  base. 
EM.  several  figures.  Europe,  Asia, 
Australia,  Africa,  America.  1-960". 
"More  slender  and  with  sharper  point 
than  G.  cristatum,''^  Rab.  Professor 
Kiitzing  unites  G.  cristatum  to  this  spe- 
cies; and  certainly  they,  as  well  as  G. 
Lagemda,  seem  closely  allied.  Ehren- 
berg's  figm'es  vary  considerably  in  form, 
but  all  have  the  apex  more  cuneate  than 
we  have  ever  seen  it  in  G.  cristatum. 

G.  Lagemda  (K.).  —  Slender,  linear- 
cuneate,  finely  striated;  lateral  view 
clavate,  crowned  with  a  minute  point, 
tapering  and  subacute  at  base.  KB. 
p.  85,  pi.  30.  f.  60.  =  G,  sphm'ophorum,  EM. 
pi.  35  A.  7.  f.  14.  America,  Europe. 
Stipes  short.  1-720".  This  form  ap- 
parently difiers  from  G.  cristatum  only 
in  its  narrower  frustule. 

G.  apiculatum  (E.). — Cuneate ;  lateral 
view  obovate,  with  acute  cuneate  apex 
and  tapering  base.  EM.  pi.  4.  2.  f.  39. 
Fossil.  America,  (xn.  28  &  53.)  ^3 
more  slender  than  G.  apiculatum :  EM. 
pi.  2.  2.  f.  43. 

G.  Turris  (E.).  —  Much  elongated, 
clavate,  its  apex  suddenly  acutely  cu- 
neate. EM.  several  figm'es.  Africa, 
America,  India,  Japan.  Ehrenberg's 
figures  vary  in  form,  but  are  mostly 
clavate,  with  or  without  a  slight  con- 
striction above  the  middle.  "Akin  to 
G.  gracile,  but  stouter,"  E. 

2 1  Apex  in  lateral  view  neither  acute 
nor  apiculate. 

G.  ahhreviatum  (Ag.).  —  Frustules 
broadly  cuneate,  conjoined  in  a  flabel- 
late  manner ;  lateral  view  obovate,  with 
indistinct  strise  and  romided  apex.  KB. 
p.  84,  pi.  8.  f.  5-7.  =  Echinella  ahhreviata, 
Ehr.  /3.  longipes  (K,),  stipes  elongated; 
subbranched,  =  G.  rotundatttm,  E.  Eu- 
rope, Asia,  Australia,  America.  1-1152" 
to  1-840".  Stipes  rather  thick,  usually 
very  short  and  simple,  but  in  var.  ^ 
more  elongated. 

G.  spheneUoides  (Rab.).  —  Obovate, 
smooth,  with  broadly  roimded  apex; 
stipes  simple,  stout.  Rab  D.  p.  58,  pi.  8. 
f.  1.  Italy.  Front  \"iew  cimeate.  Pro- 
bably only  a  fonn  of  G.  ahhreviatum. 

G.  micropus  (K.). — Front  view  linear- 
at  each  end ;  lateral 


view  obovate-lanceolate.  KB.  p.  84, 
pi.  8.  f.  12.  Germany,  France.  Very 
finely  striated?;  stipes  very  short  and 
obsolete,  or  elongated  filiform  and  sub- 
ramose.  "  Resembles  G.  spheneUoides, 
but  is  smaller  and  more  slender,"  R.  I.  c. 

G.  tenellum  (K.).  —  Minute,  smooth; 
lateral  view  obovate-lanceolate;  stipes 
abbreviated,  simple.  KB.  p.  84,  pi.  &. 
f.  8.     Em-ope.     1-1440". 

G.  Persicum  (Rab.). — Lateral  view 
obovate,  \sdth  rounded  upper  end,  stri- 
ated ;  front  view  broadly  cuneate.  Rab  D. 
p.  59,  pi.  8.  f.  4.  Persia.  The  figm-e  re- 
presents the  front  view  with  conspi- 
cuous terminal  puncta  and  longitudinal 
^dttae  or  sutm^e-like  lines. 

G.  Hercynicum  (Rab.). — Lateral  view 
obovate-lanceolate,  with  obtuse  ends, 
the  upper  one  cuneate;  striae  distinct; 
front  view  broadly  cimeate.  Rab  D. 
p.  59,  pi.  8.  f.  28. 

G.  suhramosum  (Ag.).  —  Lateral  \'iew 
clavate ;  front  view  cuneate,  with  acute 
base ;  stipes  long,  slender,  nearly  simple. 
KB.  p.  85;  pi.  8.  f.  15.  =  G.  septatum,  Ag 
CD. ;  G.  oculatum,  KSA. ;  G.  discolor  and 
G.  clavatum,  E.  (according  to  Kiitzing). 
Common.  Europe,  Asia,  Africa,  Ame- 
rica. 1-1140"  to  1-600".  Strite  very 
faint.  We  quote  G.  clamtum  (E.)  imder 
this  species  in  deference  to  Kiitzing's 
authority,  because  the  description  will 
not  determine  the  question ;  and  although 
Ehrenberg,  in  his  'Microgeologie,'  figures 
it  from  more  than  twenty  stations,  yet 
those  fio-m*es  differ  so  greatly  as  to  afford 
no  decisive  information  :  several  of  them 
are  lanceolate  or  clavate,  whilst,  like  G. 
Glans  (a  species  indeed  described  as 
having  a  general  resemblance  to  G.  clava- 
tmii),  the  greater  number  have  an  inflated 
centre. 

G.  erosum  (Rab.).  —  Oblong-obovate, 
with  emarginate  apex  ;  front  view 
narrow-cimeate ;  stipes  dichotomously 
divided.  Rab  D.  p.  59,  pi.  10.  f.  12. 
Dresden. 

5  *  Frustules  in  latercd  view  ventricose  at 
the  middle,  attenuated  at  each  end. 

G.  Glans  (E.). — Ovate-oblong,  tumid; 
upper  end  rounded,  with  a  slightly  tu- 
mid neck.  EM.  pi.  4.  2.  f.  35.'  Has  a 
general  resemblance  to  G.  clavatum,  but 
is  shorter,  stouter,  and  more  obtuse. 
Ehrenberg's  figm*es  represent  it  with 
ventricose  centre,  broadly  conical  above, 
with  roimded  apex,  and  tapeiing  below 
into  a  short,  slenderer  base. 

G.  Oregonicum,  EM.  pi.  37.  2.  f.  12,  13. 
Fossil.     Oregon.     Ehrenberg's  figure  of 


890 


SYSTEMATIC  HISTORY  OF  THE  INFtlSOEIA. 


the  lateral  view  lias  an  oblong  inflated 
centre,  suddenly  constricted  al)oye  into 
a  cone  with  rounded  apex,  and  taper- 
ing below  into  a  slender  base ;  the  front 
view  is  large,  broadly  cimeate,  with 
striated  lateral  margins,  rounded  base, 
and  conspicuous  puncta  at  upper  end. 
It  differs  from  G.  Glans  in  its  larger  size 
and  more  elongated  inflated  centre. 

G.  IlamUla,  EM.  pi.  37.  2.  f.  10.  Ore- 
gon. Ehrenberg's  flgure  of  the  lateral 
view  resembles  G.  Oregonicinn,  but  is 
stouter  in  proportion  to  its  length,  and 
the  basal  end  is  shorter  and  more 
truncate. 

G.  giganteiim  (E.).  —  Very  large  and 
tiu'gid,  distinctly  striated,  lanceolate, 
the  subacute  apex  rather  more  acute 
than  the  base.  EIIBA.  1852,  p.  534. 
Recent.  California.  It  is  more  akin  to 
G.  IfamiUa  than  to  G.  Herculeanmn, 
but  diflers  in  its  larger  size  and  slenderer 
base.     Centre  inflated. 

G.  Herculeamnn  (E.). — Very  large, 
minutely  striated,  oblong,  inflated  at  the 
middle ;  the  ends  attenuate  and  rounded, 
the  basal  one  slenderer.  EM.  pi.  35  a. 
7.  f.  12,  13.  Lake  Michigan,  Niagara, 
and  Oregon.  Stipes  long,  hyaline,  dicho- 
tomous ;  length  of  frustule  1-216".  Pro- 
fessor Kiitzing  miites  this  form  to  G. 
geminatum ;  but  according  to  Ehrenberg's 
figm-es,  they  are  ver}^  di fferent.  The  upper 
end  is  figured  in  this  species  as  broadly 
conical,  not  dilated  into  a  head  as  in 
G.  geminatum.  The  front  view  is  repre- 
sented as  more  cimeate,  and  fm-nished 
with  conspicuous  puncta  at  the  upper 
end. 

G.  inti-icatiim  (K.).  —  Inflated  at  the 
middle,  much  produced  at  each  end, 
narrow,  obtuse ;  stipes  rather  rigid,  mu- 
cous, extremely  interwoven,  dichoto- 
mous.  KB.  p.  87,  pi.  9.  f.  4.  Germany. 
Forms  a  firm  slimy  stratum  on  rocks. 
1-420''.  This  species  is  described  and 
figured  by  Kiitzing  and  Eabenhorst  as 
slender,  with  inflated  centre,  whilst  Smith 
describes  the  British  forms  as  lanceolate, 
— a  difference  which  renders  their  iden- 
tity problematical.  Front  view  narrow- 
cuneate. 

G.  longiceps,  EM.  pi.  7.  3b.  f.9.  Appa- 
rently common,  since  Ehrenberg  gives 
thirty-eight  habitats  in  Europe,  Asia, 
Australia,  Africa,  and  America.  We 
have  seen  no  description  of  this  species ; 
the  figm'es  represent  it  as  narrow-cune- 
ate  in  the  front  view,  and  the  lateral 
view  striated,  inflated  at  the  centre,  with 
the  ends  elongated  into  beaks,  the  apex 
obtuse,  and  the  base  truncate. 


G.  veiitricosum  (Greg.).  —  Much  in- 
flated at  the  centre,  upper  end  conical, 
lower  slender,  constricted  above  the 
roundish  base.  Greg.  MJ.  p.  4,  pi.  1.  f.  40. 
Scotland.  -0013"  to  -0018".  This  form 
much  resembles  G.  Glans ;  the  base,  how- 
ever, is  dilated  and  rounded — characters 
wanting  in  the  figures  of  that  species. 

G.  Cggnus  (E.). — Narrow,  T\'itli  a  lan- 
ceolate inflated  centre,  and  linear,  elon- 
gated, beak-like  extremities.  EM.  pi.  5. 3. 
f.  33.  America,  Asia.  Obtuse  at  apex, 
and  truncate  at  base.  Kiitzing  thinks 
this  may  be  identical  with  his  Splienella 
rostellata. 

G.  Vibrio  (E.).  —  Elongated,  inflated 
at  the  middle,  and  gradually  tapering 
into  long  beak-like  extremities  :  the 
upper  one  subacute.  EM.  pi.  39.  3.  f.  71. 
Cayenne.  SD.  i.  p.  81,  pi.  38.  f.  242. 
(xn.  35.)  "Akin  to  G.  gracile,  but 
longer,  more  slender,  and  approaching 
to  Pinmdaria  amphioxys^^  (E.). 

G.  rostratiwi  (Sm.).  —  Lateral  view 
ovate-elliptical,  produced  at  the  upper' 
extremity  into  a  linear  obtuse  rostrum, 
slightly  constricted  below;  striae  30  in 
•001".  SBD.  ii.  p.  99.  Barlevlake,  Co. 
Cork.    -0009"  to  -0012".    Stipes  distinct. 

G.  ?  Hehridense  (Greg.). — Lateral  view 
elongated,  narrow-lanceolate,  -«dth  in- 
flated centre,  acute  equal  apices,  and 
very  fine  striae.  Greg.  M  J.  ii.  p.  99.  pi.  4. 
f.  19.  Mull  deposit.  Professor  Gregoiy 
remarks  that  it  seems  to  stand  between 
G.  tenellum  and  G.  Vibi'io,  but  that,  only 
its  lateral  \iew  having  been  seen,  its 
genus  is  imcertain. 

6  *  Frustules  lanceolate  in  the  lateral 
view. 

G.  dichotomum  (K.).  —  Lateral  view 
naiTow-lanceolate,  with  slightly  obtuse 
apices,  striated ;  front  view  narrow- 
linear,  cuneate.  SD.  i.  p.  79,  pi.  28. 
f.  240.  =  G.  gracile,  EM.  numerous  figures. 
Common.  1-1150"  to  1-860".  Stipes 
usually  elongated  and  dichotomous,  but 
sometimes  abbreviated  and  sub-simple. 
The  frustules  somewhat  resemble  those 
of  G.  olivaceiim,  but  are  narrower ;  their 
puncta  also  are  far  less  distinct.  This 
species  appears  generally  diffused,  since 
Ehrenberg  gives  upwards  of  100  habitats, 
scattered  over  the  world. 

G.  lanceolatum  (E.).  —  Lateral  view 
striated,  lanceolate,  with  acute  ends; 
front  view  linear-cuneate,  very  gradu- 
ally tapering  at  each  end.  KB.  p.  87, 
pi."  30.  f.  59.  America.  Ehrenberg's 
figures  represent  the  lateral  view  broader 
than  in  G.  dichotomum. 


OF  THE  GOMPHONEME^. 


891 


G.  affine  (K.)*  —  Ratlier  turgid,  elon- 
gate, striated ;  margins  in  front  view 
slightly  curved;  lateral  view  sublan- 
ceolate,  with,  an  obtuse  apex.  KB.  p.  86, 
pi.  30.  f.  54.  Trinidad.  1-3G0".  Stipes 
abbreviated,  subramose.  "  It  diifers  from 
G.  dichotomum  in  its  tinner  habit  and 
broader  sides;  lateral  apices  more  ob- 
tuse "  (K.).  According  to  Rabenhorst,  it 
is  slenderer  than  G.  lanceolatum,  but 
scarcely  specifically  distinct. 

G.  Fibula  (Breb.).  —  Slender,  elon- 
gated, veiy  narrow-cuneate  ;  lateral 
view  acicular,  very  slender;  stipes  short, 
nodule  obsolete.  KSA.  p.  65.  France, 
England.  Akin  to  G.  dichotomum,  but 
dift'ers  in  its  slenderer  frustules. 

G.  exigimm  (K.).  —  Minute,  smooth, 
lateral  view  lanceolate;  stipes  slender, 
subramose.  KB.  p.  84,  pi.  30.  f.  58.  Ma- 
rine.    France,  Jutland.     1-1440". 

G.  cusjndatum  (Rab.). — Cuneate,  often 
curved ;  lateral  view  smooth,  lanceolate, 
with  acute  ends.  Rab  D.  p.  59,  pi.  8. 
f.  22.  Saxony.  With  or  without  a 
stipes. 

G.  cequcde  (Greg.). — Lateral  view  lan- 
ceolate, wdth  minutely  capitate  apices, 
an  exactl}^  central  nodide,  and  conspi- 
cuous striae.  Greg.  MJ.  iv.  p.  12,  pi.  1. 
f.  41.  Scotland.  -001".  Striee  22  to  24  in 
•001".  It  agrees  nearly  with  some  forms 
of  G.  tenelliim,  from  which,  however,  it 
differs  in  having  much  wider  and  coarser 
striae,  and  in  the  central  position  of  the 
nodule,  Greg.  /.  c.  A  slight  constriction 
exists  beneath  each  end.  Professor  Smith 
refers  it  to  G.  tenellum. 

G.  insigne  (Greg.). — Lateral  view  lan- 
ceolate, slightly  rhomboid,  with  obtuse 
ends ;  striae  18  to  20  in  -001".  Greg.  MJ. 
iv.  p.  12,  pi.  1.  f.  39.  Scotland.  -0016" 
to  -0025".  "  Distinguished  by  its  size  and 
the  coarseness  of  its  striation.  Side  view 
doubly  conical,  the  angles  at  the  broadest 
part  being  strongly  marked."  Professor 
Smith  thinks  it  may  be  a  form  of  G. 
Sarcophagus. 

G.  Sarcophagus  (Greg.). — Lateral  view 
clavate,  lanceolate,  constricted  near  the 
extremities,  which  are  minutelv  capitate. 
Greg.  MJ.  iv.  p.  13,  pL  1.  f.  42. "  Scotland. 
•0014".  Strife  20  to  22  in  -001".  Widest 
part  about  one-third  from  apex.  Pro- 
fessor Gregory  compares  the  outline  to 
that  of  a  coffin. 

G.  mimdissimum  (K.). — Linear-cune- 
ate,  smooth,  with  a  slender  subbranched 
stipes;  lateral  view  narrow-lanceolate. 
KB.  p.  84,  pi.  8.  f.  11.  Marine.  Britain, 
(xi  .  17.)  Kiitzing  regards  this  as  the 
6r.  mimdissimum  of  Gre\411e ;  but  that 


opinion  is  doubtless  eiToneous ;  for  this 
is  a  marine,  and  Greville's  was  an  aquatic 
gathering  in  which  G.  olivacemn  and  G. 
curvatum  were  mixed  together. 

G.  auritum  (Braun.). — Broadly  cune- 
ate in  front  view,  the  upper  end  trimcate, 
with  an  awm  at  each  angle ;  lateral  view 
lanceolate,  with  a  terminal  awTi.  Rab  D. 
p.  59,  pi.  8.  f.  3.  Baden.  Habit  of  G. 
ijitricatum,  but  fiu'nished  with  awnlike 
spines, 

G.  KavicuJoides  (S.).  —  Stipes  distinct 
and  regularly  dichotomous  ;  front  view 
sublinear,  truncate ;  lateral  view  acutely 
lanceolate,  with  the  extremities  equal 
and  nodule  central.  SBD.  ii.  p.  98.  In 
the  Victoria  Regia  tank,  Edinbm-gh. 
According  to  Professor  Smith,  this  spe- 
cies, in  a  lateral  view,  is  not  to  be  di- 
stinguished from  a  Navicula,  as  the 
nodule  is  almost  exactly  central. 

Species  insufficiently  described,  or  known 
to  us  only  by  7iame. 

G.  digitatum  (K.).  —  Frustules  very 
minute  and  smooth,  linear-cuneate,  fla- 
bellate;  stipes  simple,  dilated  above. 
KB.  p.  84,  pi.  21.  f.  2.  2.  Marine.  Cux- 
haven.  1-680".  Kiitzing  gives  no  de- 
scription or  figure  of  the  lateral  view. 

G.  telographicum  K.). — Frustules  mi- 
nute and  very  smooth,  slender,  cimeate, 
somewhat  more  acute  at  base,  umbel- 
lately  aggregated  on  a  simple  abbrevi- 
ated stipes  dilated  at  its  apex.  KB.  p.  84, 
pl.8.f.9.  Maritime.  Heligoland.  1-1200". 

G.  crassum  (Rab.).  —  Front  view 
broadly  cuneate,  trimcate  above,  rounded 
at  base  ;  the  lateral  margins  convex, 
faintly  striated.  Rab  D.  p.  59,  pi.  10.  f.  13. 
Persia.  Although  only  the  front  view 
is  described  and  tigiu-ed,  yet  the  species 
seems  well  distinguished  by  the  convex 
(not  straight)  lateral  margins,  giving 
it  an  obovate  fomi  with  the  broader 
end  truncate.  The  puncta  are  conspi- 
cuous in  the  figure,  as  are  also  two  lon- 
gitudinal lines  or  vittae. 

G.  pulvinatum  (Braun).  —  Front  view 
broad,  linear-cimeate ;  base  smaller  than 
the  very  thick,  serpentine,  irregularly 
divided  "stipes.  Rab  D.  p.  58,  pi.  8.  f.  16. 
Zurich.  "  Forms  little,  very  thick,  smooth 
knoblike  cushions  of  equal  height." 

G.  ?  contractum  (K).  —  Very  minute, 
attenuated  at  the  base,  slightly  con- 
stricted at  the  middle,  with  a  dilated 
roimded  apex ;  stipes  simple,  abbreviated 
or  obsolete.  KB.  p.  86,  pi.  14.  f.  21.  3. 
Germany.  1-1440".  Kiitzing's  figiu-e, 
which  is  very  minute  and  pyrifomi, 
shows  no  median  line,  nodule,  or  striae. 


892  SYSTEMATIC  HISTOKY  OF  THE  rNFUSORlA. 


G.  insulare  (E.),  G.  temdcolle  (E.), 
Australia;  G.  longicoUe  (E.),  Australia, 
Asia,  America;  G.  Jordani  (E.),  River 
Jordan;  G.  obtmum  (E.),  Arabia,  Ame- 
rica; G.  turritum  (E.),  Arabia;  G.  mu- 
cronatum    (E.),    G.  rhomhoideum   (E,),  | 


Asia ;  G.  3Iosctmhicense  (E,),  Africa ; 
G.  Margaritaceum  (E.),  G.  Savannce 
(E.),  British  Guinea  ;  G.  lanceolatum 
(E.),  America ;  G.  Palea  (E.),  fossil, 
Jiu'a  Moimtains,  France. 


Genus  SPHENOSIRA  (E.).  —  Frustules  united  into  a  straight  compressed 
filament;  lateral  snrfaces  with  unequal  extremities  and  a  distinct  central 
nodule.  Aquatic.  The  frustules  in  front  view  are  scarcely  cuneate  ;  and  the 
genus  could  be  better  placed  in  the  IS^aviculeae,  as  indeed  Kiitzing  himself 
suggests ;  it  seems  to  differ  from  them  only  in  the  unequal  ends  of  the 
lateral  surfaces. 

Sphenosiha  Catena  (E.). — Frustules  i  what  obtuse  base.  EA.  p.  98,  pi.  3.  1. 
smooth ;  lateral  view  with  a  mucro  at  |  f.  27 ;  KB.  p.  88,  pi.  29.  f.  47.  Mexico, 
apex  and  a  gradually  attenuated,  some-  |  (xi.  30.) 

FAMILY  XYIIL— ]S"AyiCIJLE^. 

Frustules  free,  concatenate,  or  included  in  a  more  or  less  definite  fi'ond ; 
front  view  generally  linear  or  quadi^angular ;  valves  with  similar  ends,  a 
median  longitudinal  line,  and  central  nodule.  "  The  Naviculeae  frequently 
resemble  individuals  in  other  families,  but  are  to  be  distinguished  by  the 
central  nodule  of  the  lateral  surfaces,  as  well  as  by  the  regularity  and 
symmetry  both  of  these  and  the  front  view  "  (Menegh.).  In  the  minuter 
forms  the  nodules  are  frequently  very  indistinct;  when  present,  however, 
they  usually  appear,  in  the  front  view,  like  a  punctum  at  the  middle  of  each 
lateral  margin.  In  doubtful  cases  this  appearance  will  often  aid  in  ascer- 
taining their  presence. 

*  ErustuJes  nude. 

Genus  NAYICULA  (Bory,  Bab.). — Frustules  simple,  free,  prismatic  in  front 
view,  rectangular  laterally,  with  a  longitudinal  median  peUucid  line  with 
central  and  terminal  nodules,  Navicula  was  chvided  by  Ehrenberg  into  two 
genera — Navicula  with  smooth,  and  Pinnularia  with  striated  valves ;  but 
this  division  was  not  received  by  Klitzing  or  Brebisson,  and  is  certainly  un- 
sound, as  it  assigns  the  species  to  each  genus  according  to  the  power  of  the 
author's  microscope,  whilst  striae,  we  believe,  are  almost  always,  if  not  uni- 
versally, present  on  the  valves.  The  late  Professor  Smith  reconstituted 
Ehrenberg's  genera,  and  made  their  characters  depend  on  the  presence  or 
absence  of  costae.  These  characters  were  far  better  than  those  of  Ehrenberg ; 
and  were  the  costae  always  plainly  developed  as  in  Pinmdaria  nohilis  and  its 
allies,  no  difficulty  could  occur  in  determining  the  genera ;  but  in  many  of  the 
more  minute  species  it  is  often  very  difficult  to  distinguish  between  striae  and 
costas.  We  have  not  admitted  Pinnularia  here,  partly  for  the  reason  just 
given,  but  principally  because  we  cannot  decide  to  which  genus  a  large  num- 
ber of  Ehi^enberg's  species  should  be  referred. 

slightly  constricted  at  the  middle  and 


A.  Valves  more  or  less  cotistricted  at  the 
middle  (Diploneis,  E.). 

NAVicuiiA  Americana  (E.).  —  Turgid, 
linear-oblong,  with  slightly  constricted 
centre  and  broadly  roimded  ends  ;  striae 
wanting  or  indistinct.  EM.  pi.  2.  2.  f. 
16,     New  York  and  Rhode  Island. 

N.  Faba  (E.,  K.). —Turgid,  oblong, 


rounded  at  the  ends,  marked  by  longi- 
tudinal lines ;  strias  wanting  or  indi- 
stinct. =  Di])loneis  Faba,  EB.  1845, 
p.  365.  River  Tagus.  The  median  line 
interrupted  by  the  central  nodule ;  three 
lines  on  each  side  continuous. 

N.  hyalina  (E.,  K.).  —  Slightly  con- 
stricted at  the  middle,  with  oblong  lobes, 


OF  THE  NATICULE^. 


893 


roimded  ends,  a  longitudinal  median 
fascia  of  lines,  and  a  narrow  pinnulated 
horder.  =Diplo?ieis?  hi/alina,  EB.  p.  362. 
Marine.  India.  May  be  more  akin  to 
CymatopJeura  Solea. 

N.  hinodis  (E.).  —  Smooth,  minute, 
narrow  panduriform,  -vsdth  acuminated 
rostrate  apices ;  median  nodule  very 
distinct.  EB.  1840,  p.  18 ;  KB.  p.  100,  pi.  3. 
f.  So.  =  Frar/{hinaf  binodis,  EA.  p.  127. 
Fossil,  Santa  Fiore  ;  recent  in  pools,  &c. 

N.  dupUcata  (E.).  —  Smooth,  small, 
rather  broad  panduriform,  with  attenu- 
ate subacute  apices.  EM.  pi.  21.  f.  35. 
Cuba.  In  Ehrenberg's  hg-ure  the  ends 
are  somew' 
line  simple. 

N.  incurva  (Greg.). — Small,  smooth, 
sublinear,  with  a  shallow  sinus  on  each 
side,  and  ends  suddenly  contracted  into 
obtuse  subcapitate  beaks.  MJ.  iv.  p.  8, 
pi.  1.  I  2Q.     Scotland. 

N.  comtricta,  EM.  pi.  38.  17.  f.  3. 
Volcanic  ashes,  Iceland.  Ehrenberg  re- 
presents it  as  smooth,  minute,  panduri- 
form ;  ends  rounded,  each  terminated  by 
a  minute  nipple-like  point ;  median  line 
simple. 

N.  emarglnata,  EM.  pi.  39.  f.  83. 
Ehrenberg's  figure  is  minute,  smooth, 
panduriform,  with  each  end  suddenly 
contracted  into  an  obtuse,  broad,  mam- 
miform beak. 

N.  paradoxa  (E.). — Large,  smooth; 
oblong,  slightly  constricted  at  the  middle, 
with  four  longitudinal  median  lines  and 
somewhat  obtuse  cuneate  ends.  EA. 
pi.  1.  3.  f.  4.  6.     Peru. 

N.  imperialis  (E.,  K.). — Dilated,  with 
constricted  middle  and  subacute  apices, 
a  simple  series  of  conspicuous  granules 
accompanying  the  middle  furrow,  which 
is  smooth  on  both  sides:  lateral  series 
alike,  two  perfect  ones  inclosing  an  im- 
perfect median  sinus,  all  interrupted  at 
the  middle.  =  Diploneis  imperialis,  EB. 
1845,  p.  362.  Marine.  India.  Granules 
large,  pearl-like. 

N.  Entomon  (E.).  —  Large  ;  slightly 
sinuato-constricted  at  the  middle,  with 
oblong  lobes  and  subacute  cimeate  ends ; 
sti-ife  19  or  20  in  1-1200".  EB.  1840. 
=  Pinmdaria Entomon,  EA.  pi.  1. 1. f.  3,  4 ; 
Diploneis  Entomon,  EM.  pi.  19.  f.  30. 
Marine.  Fossil,  Greece  ;  recent,  Eu- 
rope, Asia,  Africa.  Distinguished  by 
its  shallow  stricture  and  smooth  striae. 

N.  Conops  (E.,  K.). — Small,  panduri- 
form, very  finely  striated,  ^ath  cordate 
lobes  and  acute  apiculate  apices.  =P«;i- 
nularia?  Conops,  EA.  pi.  3.  7.  f.  20. 
America. 


N.  incurvata  (Greg.).—  Pandui-ifonn, 
with  roimded  ends;  stiiee  30  in  -001", 
minutely  moniliform ;  median  line 
straight,  with  dark  shaded  lines  on  each 
side.  TM.  iv.  p.  44,  pi.  5.  f.  13.  Marine. 
Scotland. 

N.  splendida  (Greg.).  —  Large,  pan- 
duriform, much  constricted,  with  elliptic- 
oblong  lobes  and  obtusely  triangular 
ends  ;  strise  distinctly  moniliform.  TM. 
iv.  p.  44,  pi.  5.  f  14.^  Marine.  Scotland. 
31edian  line  straight,  and  having  on  each 
side  a  narrow  blank  space. 

N.  Proserpincs  (E.).  —  Veiy  large, 
deeply  constricted ;  lobes  almost  rhom- 
boid, with  subacute  apices ;  sides  stri- 
ated, lines  decussating  at  a  right  angle, 
a  broad,  pellucid,  smooth  median  fascia 
divided  by  two  lines  into  three  parts ; 
umbilicus  circular.  =  Diploneis  Proser- 
jnnce,  EB.  1858,  p.  13.  Marine.  ^F^gean 
Sea. 

N.  Musca  (Greg.).  —  Small,  panduri- 
form, vr[\h  tiu-gid  lobes  and  acute  cune- 
ate apices ;  strine  rather  distant,  coarse, 
moniliform,  short,  forming  a  marginal 
band.  GDC.  p.  7,  pi.  1.  f.  6.  Marine. 
Scotland.  Striae  18  in  -001";  median 
line  and  nodule  distinct. 

N.  Bomhus  (E.,  K.). — Panduriform, 
with  subcordate  lobes  and  subacute 
apices  ;  striae  dense,  coarselv  moniliform. 
KSA.  p.  83.  =  Pinmdaria  Bomhus,  ERBA. 
1844;  GD.pl.  1.  f.  12;  Diploneis  Bomhus, 
EM.  pi.  19.  f  31.  Europe.  1-384"  ;  strise 
21  in  1-1200".  Granules  of  the  largest 
striae  in  fom*s.  Median  line  broad,  with 
a  square  central  nodule.  Characterized 
by  its  short  turgid  lobes  and  close,  large, 
pearly  gi-anules. 

N.  didijma  (E.,  K.).  —  Rather  broad, 
slightly  constricted  at  the  middle,  with 
short  suborbicular  lobes  and  broadly 
rounded  ends  ;  striae  distinct,  gi*anulate. 
KB.  p.  100,  pi.  4.  £  7 ;  SD.  i.  pi.  17.  f.  154. 
—  Pinmdaria  didijma,  EA.  pi.  2.  4.  f.-3. 
Marine.  Europe,  Asia,  Africa,  America. 
{ytl.  61;    XV.  12.) 

N.  dissimilis  (Rab.).  —  Large,  pan- 
duriform, with  broadly  rounded  ends ; 
striae  stout,  curved,  converging,  not 
reaching  the  median  line  ;  front  view 
gibbous  at  the  centre  and  tapering  to- 
wards the  ends,  which  are  trimcate.= 
Pinnuhria  dissimilis,  Rab.  p.  45,  pi.  6. 
f.  32.     Persia. 

l>i.  Pandu7'a  (Breb.). — Large,  elong- 
ated panduriform,  with  elliptic  lobes 
and  obtuse  apices  ;  costae  smooth.  BD. 
pi.  15.  f.  4:.  =  Pinmdaria  Pandura,  GDC. 
p.  17,  pi.  1.  f.  22  ;  K  nitida,  TM.  iv. 
p.  44,  pi.  5.  f  12.     Europe.     M.  de  Br^- 


894 


SYSTEMATIC  HISTORY  OF  THE  INTUSOIIIA. 


bisson  regards  this  form  as  distinct  from  j 
N.  Crabro,  E. ;    and   it  undoubtedly  is 
from  the  Trinidad  Diatom   figured   by 
Dr.  Greville  for  that  species.     We  con- 
sider, however,  that  N.  Pandura,  Breb. 
not  only  agrees  in  its  smooth  costae  with 
Ehrenberg's  description  and  figure  of  N.  \ 
Crabro,  but  also  better  in  shape   than  i 
does  Greville's  N.  Crabro,  in  which  the  ; 
constricted  portion  is  less  elongated — a  j 
fact  pointed  out  by  Greville  himself.         i 

N.  Crabro  (E.,  K.).  —  Panduriform,  \ 
deeply  constricted;  lobes  ovate  or  ob- 
long, with  subacute  apices ;  striae  di- 
stinct, obscurely  moniliform,  nitescent, 
10  in  -001".  KA.  p.  83  ?  ;  SBD.  ii.  p.  94  ; 
MJ.  V.  pi.  3.  f.  '\l.  =  Pi?inularia  Crabro, 
ERBA.  1844,  p.  85  ? ;  Biploneis  Crabro, 
EM.  pi.  19.  f.  29  ?  Fossil,  yEgina;  re- 
cent, America,  Em-ope.  Although  we  defer 
to  the  opinions  of  Brebisson,  Smith,  and 
Greville,  yet  we  think  it  highly  probable 
that  the  preceding  species  is  the  one 
intended  by  Ehrenberg  for  D.  Crabro. 

N.  gemmata  (Grev.). —  Broad  linear- 
oblong,  obtuse,  with  straight  or  slightly 
concave  sides  ;  striae  moniliform,  inter- 
rupted, 10  in  -001",  wath  a  single  row  of 
pimcta  near  the  median  line.  Edin. 
New  Phil.  Journ.  n.s.  x.  pi.  4.  f.  7.  Cali- 
fornian  guano.  Distinguished  by  its 
distant  striae,  which  form  a  linear  mar- 
ginal band.  Its  affinity  is  with  N.  Crabro 
and  its  allies. 

N.  tiodulosa  (Breb.,  K.). — Minute,  ob- 
long, constricted  at  the  middle ;  ends 
contracted  into  obtuse  mammiform 
beaks  ;  transverse  striae  not  reaching  the 
median  line.  KB.  p.  101,  pi.  28.  f.  71.  = 
Pinnularia  Termes,  EM.  pi.  39.  f.  100. 
Recent,  Cuba,  Mexico,  Africa;  fossil, 
Franzensbad. 

N.  fiemina  (E.).  —  Small,  striated, 
divided  by  a  median  constriction  in  both 
views  into  two  lenticular  lobes;  in  lateral 
view  terminated  by  a  median  apiculus. 
EB.  1840,  p.  19.  Mouth  of  the  River 
Elbe.     1-840"  to  1-648". 

N.  A^ns  (E.,  K.). —  Oblong,  so  much 
constricted  as  to  be  nearly  divided  into 
two  semiorbicular  lobes;  striae  slender, 
granulate  ;  stricture  smooth.  KB.  p.  100, 
pi.  28.  f.  76.  =Pmmdaria  Apis,  EA.  iii. 
pi.  7.  f.  18.  Mexico,  Africa.  Distin- 
guished by  its  smooth  stricture  and  its 
finely  granulate  striae  (12  in  1-1200"). 

N.  interrnpta  (K.).  —  Sinuato-con- 
stricted  at  the  middle,  with  broadly  ellip- 
tic lobes  and  rounded  ends  ;  striae  inter- 
rupted opposite  the  nodule.  KB.  p.  100, 
pi.  29.  f.  93.  =  Navicula,  BAJ.  1842, 
pi.  2.  f.  18.     Marine.    America,  Jutland. 


B.  Valves  divided  into  three  or  more  pov' 
tio)is  by  two  or  four  constrictions,  but 
not  constricted  at  the  centre  (Nodosae). 

N.  Silicula  (E.).  —  Smooth,  linear 
elongated,  divided  by  two  constrictions 
into  three  nearly  equal  nodes ;  apices 
obtuse.  EM.  numerous  figures.  =  N. 
ventricosa,  E.  Apparently  common,  since 
Ehrenberg  gives  upwards  of  fifty  habi- 
tats in  Europe,  Asia,  Australia,  Africa, 
and  America.  This  species  might  be 
placed  with  almost  equal  propriety  in 
the  following  section. 

N.  p)olyonca  (Breb.).  — Elongated,  ba- 
cillar,  sublinear,  divided  by  two  con- 
strictions into  three  nodes,  the  middle 
one  largest ;  ends  roundish-capitate  ; 
striae  wanting  or  indistinct.  KA.  p.  85. 
=  Pinnularia  undidata,  MJ.  ii.  p.  97,  pi. 
4.  f.  10.     France,  Britain. 

N.  Hitchcockii  (E.). —  Smooth,  linear- 
oblong,  each  margin  with  three  imdula- 
tions;  apices  suddenly  cuneate,  sub- 
acute. EM.  pi.  5.  3.  f.  11.  America. 
(VII.  62.) 

N.  litnosa  (K,). — Smooth  or  obscurely 
striated,  linear,  with  two  constrictions 
and  three  inflations,  the  middle  one 
largest ;  ends  cuneate,  subacute.  KB. 
pi.  3.  f.  50.     German3^ 

N.  nodosa  (E.). — Linear,  smooth  or  ob- 
scurely striated,  with  three  nearly  equal 
inflations;  ends  contracted  into  short  ob- 
tuse beaks.^  KB.  p.  100,  pi.  28.  f.  82.  Com- 
mon, especially  in  small  pools  by  the  road- 
side, (ix.  143.)  j3,  striae  more  evident.  = 
Pinnularia  Legumen,  EM.  many  figures. 
1-430".     Approaches  N.  Hitchcockii. 

N.  trinodisl^.). — Valves  with  two  con- 
strictions, three  nearly  equal  inflations, 
roimded  ends,  and  obscm-e  striae. 

N.  mesolepta  (E.). — Smooth,  elongated, 
linear,  with  three  inflations,  the  middle 
one  smallest;  ends  strongly  contracted 
into  short  obtuse  beaks.  EM.  pi.  17. 
2.  f.  17.     America,  France.     1-420". 

N.wu'a//s(E.). — Minute ;  linear,  some- 
what narrow  in  the  middle,  with  tri- 
crenate  sides  and  obtuse  apices.  EB. 
1853,  p.  528 ;  EM.  pi.  35  b.  a  2.  f.  5. 
Monte  Rosa.  Differs  from  iV.  undosa  in 
its  stouter  apices :  N.  nodosa  is  larger  and 
more  slender.  Ehrenberg's  figure  shows 
the  valves  very  minute,  with  four  con- 
strictions and  five  nodules,  including  the 
capitate  ends,  which  nearly  resemble  the 
others  in  size  and  form. 

N.  Formica  (E.).  —  Smooth,  linear, 
with  four  constrictions  and  five  oblong 
nodes.  EM.  pi.  4.  3,  f.  8.  Recent,  United 
States ;  fossil,  Finland. 


OF  THE  XAVICTJLEJE. 


895 


N.  Monile  (E.,  K.). —  Striated,  linear, 
constricted,  with  five,  nearly  equal  sub- 
globose  nodes,  including  the  capitate 
ends.  =  Pi/mularia  3Iomle,  EM.  pi.  17.  1. 
f.  12 ;  Pinnularia  isocepluda,  E5I.  pi.  5. 
3.  f.  21.  Berlin,  America.  It  has  the 
ends  more  capitate  and  the  striae  stronger 
than  N.  nodosa. 

N.  Kochii  (E.,  K.). — Large,  elongated, 
lanceolate,  with  subacute  apices,  each 
side  with  three  imdidations,  the  middle 
one  most  distinct;  striae  oblique  j  the 
median  smooth  band  very  broad,  extend- 
ing to  the  apices.  KA.  p.  84.  =  Pinnu- 
laria  Kochii,  EB.  1845,  p.  364.  Fossil. 
Kurdistan. 

N.  Pyrencdca  (S.). — Elongated,  slen- 
der linear,  with  three  intiations,  the 
median  one  greatest ;  strise  indistinct. 
ANH.  1857,  xix.  p.  8,  pi.  2.  f.  5.  Pyre- 
nees. 

N.  undosa  (E.).  —  Small,  smooth, 
broadly  oblong-lanceolate,  with  three 
undulations  on  each  side,  and  conical 
apices.  EM.  pi.  39.  3.  f.  90.  America, 
Africa,  Asia,  France.  Ehrenberg  de- 
scribes it  as  akin  to  N.  Hitchcockii. 
Rabenhorst  remarks  that  it  resembles  N. 
Persica  in  form,  but  is  scarcely  one-third 
its  size  and  has  no  secondary  undulating 
ribs. 

N.  Persica  (Rab.).  —  Large,  oblong- 
lanceolate,  with  obtuse  mammiform 
apices ;  each  side  with  five  undulations, 
and  four  corresponding  longitudinal  un- 
dulated lines  on  each  side  the  median 
one.  Eab  D.  p.  41,  pi.  6.  f.  65.  South 
Persia.  Broadest  at  the  centre,  and 
tapering  in  a  pjncamidal  manner  to  each 
apex. 

N.  Integra  (S.).  —  Small,  lanceolate, 
with  slightly  undulated  margins  and 
contracted  apicidate  apices;  striae  in- 
distinct, 36  in  -001",  reaching  the  median 
line  and  most  evident  opposite  the  cen- 
tral nodule.  =  Pm«?^/arm  integra,  SD,  ii. 
p.  96 ;  N.  rostrata,  MJ.  iv.  pi.  1.  f.  14. 
Britain. 

N.  undtdata.  =  Pinmdaria  mesotyla, 
EM.  pi.  16.  3.  f.  27.  Sweden,  India. 
Ehrenberg's  figau^e  somewhat  resembles 
that  of  N.  undosa  in  form,  but  is  longer 
and  has  parallel  transverse  striae. 

C.  Valves  elongated  linear  or  lanceolate, 
loith  gihhous  or  injlated  centre  ;  central 
costcs,  ivhen  present,  usually  converging, 
and  often  leaving  a  dilated  sunooth  space 
round  the  median  nodule. 

N.  mesotyla  (E.). — Small,  smooth  or 
indistinctly  striated,  narrowly  linear, 
with   a  central  spherical  inflation  and 


slightly  contracted  obtuse  apices.  EA. 
p.  131,  pi.  4.  2.  f.  7. ;  EM.  pi.  1.  3.  f.  14. 
Asia,  Africa,  America.     1-420". 

N.  inconspicua  (Greg.). — Small,smooth, 
hj^aline,  linear,  with  roimded  ends  and 
slightly  gibbous  centre;  median  line 
strong,  complex,  interrupted  by  the  de- 
finite central  nodule.  GD.  p.  6,  pi.  1.  f. 
3.     Scotland. 

N.  IcBvissima  (K.). — Minute,  vitreous, 
clear,  linear,  with  broadly  rounded  ends 
and  slightly  gibbous  centre  ;  striae  want- 
ing or  indistinct ;  central  nodule  stauros- 
like.  KB.  p.  96,  pi.  21.  f.  14.  =  Staw  ^ 
roneis  rectangidaris^  MJ.  ii.  pi.  4.  f.  17 
(according  to  Smith).  Fossil,  Santa 
Fiore;  recent,  Britain.     1-570". 

N.  tmnidula  (Rab.).  —  Small,  linear, 
with  rounded,  slightly  enlarged  ends,  and 
inflated  centre ;  central  nodule  stout. 
RabD.  p.  41,  pi.  5.  f.  9.  Stockholm. 
Closely  allied  to  N.  Silicula. 

N.  scopulorum  (Breb.).  —  Elongated, 
slender  linear,  with  central  and  terminal 
inflations  ;  striae  very  faint,  reaching  the 
median  line,  56  in  -001".  KA.  p.  81.  = 
N.  mesotyla,  KB.  p.  99,  pi.  5.  f.  3 ;  Pin- 
nularia Johnsonii,  SD.  i.  pi.  19.  f.  179. 
In  marine  or  brackish  waters.  France, 
Britain.  Front  view  turgid  at  the  middle. 
M.  de  Brebisson  assures  us  that  Smith's 
species  is  identical  with  his  N.  scopu- 
lorum; but  Kiitzing's  figiu-e  and  descrip- 
tion would  not  lead  us  to  infer  the 
identity. 

N,  gibherula  (K.). — Linear,  with  gib- 
bous centre  and  very  slightly  enlarged, 
obtuse,  subtruncate  apices ;  striae  very 
fine.   KB.  p.  101,  pi.  3.  f.  50*.     Em-ope. 

N.  leptogongyla  (E.).  —  Elongated, 
slender  linear,  striated,  tumid  in  the 
middle  ;  apices  slightly  dilated,  oblong, 
obtuse.  KB.  p.  99,  pi.  4.  f.  9 ;  EA.  p. 
130.  =  Pinmdaria  leptogongyla,  EM. 
many  figures.  Em-ope,  America.  Lough 
Moume  deposit.  Rabenhorst  saj^s  that 
this  species  has  double  the  breadth  of 
N.  scojmlorum. 

N.  mesogongyla  (E.,  K.).  —  Styliform 
or  baciUar,  striated,  with  gibbous  middle, 
and  broadly  rounded  but  not  dilated 
ends.  KA.  p.  81.  =  Pinnularia  meso- 
gongyla, EM.  pi.  10.  2.  f.  2.  Asia,  Africa, 
America.  Akin  to  N.  nohilis,  but  with- 
out dilated  ends. 

N.  nohilis  (E.,  K.). — Very  large,  elon- 
gated, broadly  linear,  gradually  dilated 
at  centre,  and  broadly  rounded  ends ; 
costae  oblique,  stout,  close,  not  reaching 
the  median  line.  KA.  p.  80.  =  Pin- 
mdaria nohilis,  EB.  1840,  p.  20  ;  SD.  i. 
pi.  17.  f.  161.     Em'ope,  America,  Asia, 


896 


SYSTEMATIC  HISTORY  Or  THE  INFUSORIA. 


Australia.  1-84" ;  nodules  large ;  costae 
16  to  18  in  1-1200". 

N.  gigas  (E.,  K.). — Very  large,  elon- 
gated ;  broadl}^  linear,  with  gibbous  centre, 
and  broadly  rounded,  slightly  attenuated 
ends ;  costae  broad,  close,  not  reaching 
the  median  line.  KA.  p.  d>0.=Pinnidaria 
gigas,  EM.  pi.  2.  3.  f.  1.  America.  Akin 
to  N.  nobilis;  nine  pinnules  in  1-1200". 

N.  major  (K.). — Large,  turgid,  linear- 
oblong,  with  slightly  tumid  centre  and 
broadly  rounded  ends ;  costse  converg- 
ing at  the  centre,  stout,  12  in  1-1200". 
KB.  p.  97,  pi.  4.  f.  19,  20.  =  Pimmlaria 
major,  SD.  pi.  18.  f.  161 ;  Pimmlaria 
viridis,  E.,  in  part.  Common.  (^t;i.  65 ; 
XII.  15,  31;  XYi.  1-6.)  This  species 
scarcely  differs  from  N,  nobilis  and  JV. 
gigas,  except  by  its  somewhat  smaller 
size  and  closer  pinnules. 

N.  acrosphceria  (K.).  —  Elongated, 
slender  linear,  with  dilated  centre  and 
ends,  rounded  apices,  and  seventeen  short 
thick  costse  in  1-1200",  which  do  not 
reach  the  median  line.  KB.  p.  97,  pi.  5. 
f.  2.  =  Pimmlaria  acrosphceria,  RabD. 
p^  45,  pi.  6.  f  36 ;  SD.  pi.  19.  f.  183. 
Europe.     Front  view  narrow-linear. 

^ .  p)achi/p)tera  (E.,  K.). — Large,  bacil- 
lar,  but  short  and  stout,  with  gibbous 
centre  and  broadly  rounded  ends,  which 
are  not  constricted ;  pinnules  stout,  not 
reaching  the  median  line,  6  in  1-1200". 
KB.  p.  98,  pi.  28.  f  58.  =  Pimmlaria 
pachyptera,  E.     Labrador,  Australia. 

N.  hehes  (Ralfs). — Small,  oblong,  with 
gibbous  centre  and  broadly  obtuse  ends ; 
strise  distinct,  33  in  -001",  nearly  reach- 
ing the  median  line.=iV!  ohtusa,  SD.  i. 
p.  50,  pi.  16.  f.  140.     Britain. 

N.  cocconeiformis  (Greg.).  —  Small, 
subelliptic,  with  tumid  centre  and  slightly 
contracted,  broad,  obtuse  ends  ;  striae  in- 
distinct, median  line  straight,  nodide 
definite.  MJ.  iv.  p.  6,  pi.  1.  f.  32; 
Grey.  ANH.  2nd  series,  xy.  pi.  9.  f.  6. 
Scotland.  It  much  resembles  Acknanthi- 
dium  Jlexellum,  but  its  median  line  is 
quite  straight,  Greg. 

N.  3Iacida  (G.). — Small,  oblong,  with 
tumid  middle,  and  very  broad,  subtrun- 
cate  ends ;  striae  very  fine,  parallel,  nearly 
reaching  the  median  line,  except  opposite 
the  large,  transverse,  quadrate  indefinite 
median  space.  TM.  iv,  p.  43,  pi.  5.  £  9. 
Marine.  Britain.  Stri^  about  70  in 
•001".  In  shape  not  unlike  large  speci- 
mens oiAchnanthidium  Jlexellum,  but  the 
median  line  is  straight.  The  central 
nodule  is  obsolete  and  is  replaced  by  the 
large,  stain-like  blank  space,  Greg. 

N.  gibba  (E.,  K.). — Bacillar,  striated. 


lanceolate,  with  dilated  capitate  ends. 
KB.  p.  98,  pi.  28.  f.  70.  =  Pimmlaria 
gibba,  EA.  pi.  1.  2.  f.  3;  SD.  pi.  19.  f 
180.  Common.  Europe,  Asia,  Africa, 
America.  Striae  close,  not  reaching  the 
median  line,  30  in  -001". 

IS.Tabellaria  (E., K.).— Bacillar,  elon- 
gated, striated,  rather  turgid,  ventricose 
at  the  middle,  with  dilated,  broadly 
rounded  apices.  KB.  p.  98,  pi.  28.  f.  79. 
=  Pimiidaria  Tahellaria,  EA.  pi.  2.  1. 
f  26  ;  SD.  i.  pi.  19.  f.  181.  Europe,  Asia, 
Africa,  America,  (xn.  21.)  The  central 
dilatation  tapers  less  than  in  N.  gibba, 
and  the  striae  are  more  distant.  It  is 
more  slender  than  N.  nobilis. 

N.  por recta  (E.,  K.).  —  Large,  elon- 
gate-lanceolate, broadly  tumid  at  the 
middle,  and  gradually  tapering  into  the 
broadly  obtuse  apices;  striae  oblique. 
IlA.  p.  81.  =  Pimmlaria  porrecta,  EA. 
p.  133.  North  America.  Akin  to  N. 
decurrens. 

N.  decurrens  (E.,  K.). —  Striated,  nar- 
row, elongate-lanceolate,  tumid  at  the 
centre,  somewhat  narrowing  towards  the 
ends,  which  are  broadly  rounded.  KA. 
p.  81.  =  Pimmlaria  decurrens,  EM.  many 
figures.  /3  slenderer,  =  P/wwi//ana  Tra- 
becula,  E.  y,  striae  obsolete,  =  Navicula 
Trabecula,  E.  Ehrenberg  gives  upwards 
of  80  habitats.     Akin  to  N.  gibba. 

N.  Esox  (E.,  K.). — Large,  elongated, 
striated,  narrow-lanceolate,  with  slightly 
gibbous  centre  and  attenuated  but  obtuse 
ends ;  striae  parallel,  nearly  reaching  the 
median  line.  KB.  p.  94,  pi.  28.  f.  53.  = 
Pinmdaria  Esox,  EA.  p.  133,  pi.  1.  2.  £  4. 
Chili,    (xii.  43.) 

D.    Valves  with  a  sjnooth,  transverse 
■middle  fascia. 

N.  cardinalis  (E.).  —  Large,  broadly 
linear,  with  rounded  ends  ;  costae  stout, 
radiant,  9  in  -001",  interrupted  by  a 
smooth,  transverse  median  band.  =Pm- 
nidaria  cardinalis,  SD.  i.  pi.  19.  £  166 ; 
Stauroptera  cardinalis,  EM.  several  fi- 
gures ;  Stam'oneis  cardinalis,  KB.  p.  106, 
pi.  29.  £  10.  Europe,  Asia,  Australia, 
Africa,  America,  (xii.  72.)  A  well- 
marked  species,  easily  recognized  by  its 
large  size,  rounded  not  attenuated  ends, 
and  coarse  striae,  which  are  shorter  near 
the  transverse  median  fascia.  Perhaps 
this  and  other  species  having  a  trans- 
verse smooth  median  fascia  might  ad- 
vantageously be  retained  in  Stam-oneis, 
notwithstanding  that  the  fascia  is  not 
formed  by  a  thickened  prolongation  of 
the  central  nodule. 

N.    divergens  (S.).  —  Large,   oblong- 


OF  THE  N-iTICFLE^. 


897 


lanceolate,  somewhat  contracted  towards 
the  rounded  ends ;  costas  radiate  at  cen- 
tre, interrupted  bv  a  smooth  ti;ansyerse 
median  fascia,  11  in  -001",  =  Pinmdaria 
diver  gens,  SD.  i.  p.  57,  pi.  18.  f.  177. 
Britain.  The  costse  near  the  central  no- 
dule are  shorter  and  radiant ;  the  others 
are  divergent. 

N.  Brebissonii  (K.).  —  Linear -oblong-, 
with  obtuse  ends  ;  costte  fine,  indistinct, 
close,  30  in  -001",  not  reaching-  the  me- 
dian line,  interrupted  by  a  transverse 
median  fascia.  KB.  p.  93,  pi.  3.  f.  49.  = 
Pinnularia  stauroneiformis,  SD.  i.  p.  57, 
pi.  19.  f.  178.  Europe.  Front  view 
linear,  with  rounded  angles. 

N.  glohiceps  (Greg.). — Minute,  narrow 
linear-oblong,  constricted  beneath  the 
globular  ends;  costse  fine,  distinct,  not 
reaching  the  median  line,  interrupted  by 
a  transverse  median  blank  band,  36  to 
40  in  -001" .  =  Pin ?mlana  glohiceps,  MJ. 
iv.  p.  10,  pi.  1.  f.  34.  Scotland.  Di- 
stinguished by  its  capitate  apices  and 
transverse  cross-lihe  median  band, 

N.  parva  (E,).  —  linear,  constricted 
beneath  the  capitate  ends ;  costse  24  in 
•001",  interrupted  at  the  middle  by  a 
transverse,  blank,  cross-like  band.  =  Siau- 
roptera  parva,  EA.  p.  135,  pi.  3.  1.  f.  19  j 
Stauroneisparm,  KB.  p.  106,  pi.  29.  f.  23 ; 
Pinnularia  interrupta,  SBD.  i.  p.  59, 
pi.  19.  f.  184.  Em-ope,  Asia,  America. 
Transverse  band  dilated  outwards. 

N.  Bohemica,  EM.  pi.  10.  1.  f.  4. 
Bohemia.  Ehrenberg's  figure  is  rhom- 
boid, vidth  obtuse  apices,  three  median 
lines,  between  which  and  the  margins 
are  longitudinal  series  of  dots,  all  inter- 
rupted by  a  transverse  median  blank 
space,  but  no  distinct  nodule ;  front  view 
nan'ow-linear,  with  rounded  ends. 

N.  Claviculus  (Greg.). — Narrow-linear, 
with  two  constrictions ;  central  inflation 
small,  smooth;  terminal  ones  oblong- 
clavate,  striated;  strise  parallel,  nearly 
reaching  the  median  line,  about  32  in 
•001".  GD.  p.  6,  pi.  1.  f.  5.  Scotland. 
Nodule  definite  ;  front  view  linear,  with 
roimded  angles,  broader  than  the  lateral 
view,  the  margins  striated  except  at  the 
middle. 

E.  Frustules  in  the  lateral  view  having  the 
stricB  on  each  side  of  the  median  line 
divided  into  two  series  (a  marginal  and 
a  median)  hy  a  longitudinal  line,  blank 
space,  or  fascia. 

t  Valves  elliptic. 

N.  Lyra  (E.).  —  Elliptic  or  elliptic- 
oblong,  marked  by  two  naiTow  longi- 


tudinal blank  spaces,  which  are  con- 
nected by  the  central  nodule,  in  the  form 
of  a  Ip-e ;  striae  22  to  24  in  -001",  often 
indistinct,  the  middle  ones  longest.  = 
Navicula  and  Pinmdaria  Lyra,  E.,  GD. 
p.  13,  pi.  1.  f.  13;  N.  Gregoriana,  Grev, 
MJ.  V.  p.  10,  pi.  3.  f.  7.  Marine.  Europe, 
Asia,  Africa, America.  N.  Lyra,  var.  recta, 
Grev.,  large,  oblong-lanceolate  obtuse; 
blank  lines  narrow,  contracted  at  the  no- 
dule, otherwise  parallel  with  the  median 
line ;  striae  24  in  -001" :  Edin.  New  Phil. 
Jour,,  n.St,  X.  pi.  4.  f.  3 :  Califomian 
guano  :  distinguished  b}^  its  large  size 
and  straight  blank  lines.  Either  N,  Lyra 
is  very  variable,  or  more  than  one  species 
has  been  included  under  the  name.  The 
valve  is  either  rounded  at  the  ends  or 
(more  usually)  has  a  short,  produced, 
cx)nical  point.  The  blank  spaces  are 
linear,  inclined  inwards  at  the  nodule, 
and  the  tips,  which  are  attenuated,  usu- 
ally bent  outwards,  but  are  sometimes 
straight  or  even  incurved. 

_N.  approximata  (Grev,).  —  Oblong, 
with  produced,  conic  apices  ;  striae  inter- 
rupted, 17  in  -001" ;  outer  band  broad,  not 
dilated  opposite  the  nodule  ;  blank  lines 
linear,  nearly  sti'aight.  Grev,  Edin,  New 
Phil.  Jour.,  U.S.,  x.  pi.  4.  f.  10.  Californian 
guano.  Allied  to  N.  Lyra,  but  distin- 
guished by  the  total  absence  of  any  con- 
traction of  the  blank  spaces  opposite  the 
nodule.  From  N.  Hennedyi  it  difters  in 
its  linear,  subparallel  blank  spaces,  and 
larger  blank  space  round  the  nodule. 

N.  irrorata  (Grev.).~Broad,  parallelo- 
gramic  or  oblong,  suddenly  contracted 
at  the  ends  into  mammiform  apices ; 
striae  15  in  •OOl",  fomiing  a  broad-linear 
marginal  band,  and  a  narrow  one  of  very 
imequal  breadth  next  the  median  line ; 
blank  spaces  not  reaching  the  ends. 
Grev.  /.  c.  f.  1.     Californian  guano. 

N.  forcipata  (Grev.). — Oval  or  oblong, 
with  rounded  apices,  and  marked  by  two 
narrow  longitudinal  blank  spaces,  which 
diverge  from  the  nodule  in  a  cm^ved 
manner  and  converge  at  the  apices; 
striae  35  in  -001",  the  middle  ones  longest. 
MJ.  vii.  pi.  6.  f.  10, 11.  Marine.  Britain. 
Distinguished  from  N.  Lyra  by  its 
smaller  size,  closer  striae,  and  connivent 
points  of  the  blank  spaces. 

N.  mimmularia  (Grev.).  —  Suborbi- 
cular;  striae  moniliform,  about  24  in 
•001",  interrupted  by  two  narrow-linear 
blank  lines  which  contract  opposite  the 
nodule,  then  cm^v^e  outwards,  converge, 
and  meet  at  the  terminal  nodides.  Grey. 
Edin.  New  Phil.  Jom'.,  n.s.,  x.  pi.  4.  f.  6. 
Californian  guano.  Valve  small;  striae 
3  M 


898 


SYSTEMATIC  HISTOHY  OI'  THE  INFUSOEIA. 


concentric  with  the  extremities.      The  ; 
blank  spaces  have  a  considerable  resem- 
blance to  those  of  N.  forcipata,  Grev.        \ 

N.  sjjectabilis  (Greg.). —  Broadly  ellip-  | 
tic,    gradually   tapering   to   the    obtuse  I 
apices  ;  blank  spaces  broadly  linear,  con-  j 
verging  at  nodide  and  ends ;  striae  22  in  [ 
•001",   coarsely    moniliform,   the    outer 
series  forming  a  broad   marginal  band 
much  dilated  opposite  the  nodule.     GD. 
p.  9,  pi.  1.  f.   10.     Marine.     Scotland. 
Large    (inner)   bands    of   striae    linear. 
Distinguished  from  N.  Lyra  by  broader 
blank  spaces  and  the  brown  colour  of 
the  striated  portions ;  its  nodule  also  is 
indefinite. 

N.  siihorhicularis  (Greg,).  —  Small, 
broadly  oval  or  suborbicular  ;  striae  con- 
spicuous, about  18  in  -001",  divided  by  a 
longitudinal  line  into  two  series,  outer 
one  broadest  opposite  the  indefinite  cen- 
tral nodule.  =  N.  Smitliii  suborhicularis. 
GD.  p.  15,  pi.  1.  f  17.  Marine.  Scotland. 

N.  Coiqjeri  (Bailey).  —  Largo,  oblong, 
ysAih.  slightly  constricted  sides  and  con- 
tracted mammiform  apices  ;  striae  punc- 
tate, divided  into  series  by  two  narrow 
longitudinal  blank  bands  united  by  the 
transverse  nodule.  =  Pinmdaria  Coiiperii, 
BMO.  p.  39,  pi.  2.  f.  3.  United  States. 
The  outline  is  like  that  of  N.  paradoxa ; 
and  the  markings  somewhat  resemble 
those  of  N.  Lyra,  /3.  Blank  spaces  con- 
nivent  at  their  apices. 

N.  Ilenncdyi  (S.).  —  Elliptical,  with 
rounded  or  mammiform  ends  ;  striae  mo- 
niliform,  divided  into  series  by  two  nar- 
row, lunate  longitudinal  blank  spaces, 
the  marginal  series  of  nearly  equal 
breadth  throughout.  SBD.  ii.  p.  93: 
Greg.  MJ.  iv.  pi.  5.  f.  3.  =  Stauronois  cm- 
qulata,  Johnston,  MJ.  viii.  p.  13.  Marine. 
Britain,  (vii.  69.)  Strire  24  in  -001", 
not  perceptibly  longer  opposite  the  cen- 
tral nodide,  which  is  indefinite. 

N.  clavata  (Greg.). — Broadl}^  elliptical, 
with  apices  produced  into  mammiform 
points ;  striae  moniliform,  divided  into 
series  by  two  arcuate  longitudinal  blank 
spaces  bent  outwards  at  their  ends ; 
marginal  series  of  nearlv  equal  breadth 
throughout.  TM.  iv.  pi.  6.  f.  17.  Marine. 
Scotland.  Striae  20  in  -001",  not  per- 
ceptibly longer  opposite  the  central  no- 
dule, which  is  indefinite. 

N.  nehiilosa  (Greg.). — Elliptic-oblong; 
blank  spaces  large,  semilunate ;  striae 
fine,  34  to  36  in  -001",  forming  a  narrow 
marginal  band  of  equal  breadth.  GD. 
p.  8,  pi.  1.  f  8.  Marine.  Scotland.  Inner 
bands  of  striae,  veiy  narrow  linear,  close 
to  median  line.     Aspect  of  valve  hazy 


and  indistinct;  striated  portions  bluish 
under  a  low  power  ;  nodule  indefinite. 

N.  pratexta  (E.).  —  Large,  elliptic 
with  broadly  rounded  ends ;  striae  di- 
stinctly moniliform,  8  to  10  in  -001", 
forming  a  marginal  border  of  nearly  uni- 
form breadth,  which  is  separated  from 
the  narrow  median  band  by  a  large 
sparsely  granular  space  on  each  side. 
EB.  1840,  p.  20;  GD.  p.  9,  pL  1.  f.  11. 
^Finmdaria prcetexta,  EM.  pi.  19.  f.  28. 
Marine,  Scotland;  fossil,  Greece.  1-288". 
This  species  is  distinguished  by  its  large 
size,  coarse  striation,  much  rounded  ends, 
and  a  broad  semilunate  space  between 
the  marginal  and  inner  bands  of  stria?, 
furnished  with  scattered  granides. 

N.  Californica  (Grev.).  —  Broadly 
elliptic,  with  flattened  sides ;  striae  mo- 
niliform, divided  into  narrow  marginal 
and  median  bands  by  a  large,  semilu- 
nate, smooth  intermediate  space  on  each 
side  the  median  line.  Grev.  Edin.  New 
Phil.  Jour.,  U.S.,  x.  pi.  4.  f.  5.  Calif ornian 
and  S.  African  guanos.  Marginal  sti*i£e 
20  in  -001".  Dift'ers  from  N.  prmtexta  in 
having  the  sides  of  the  valve  flattened, 
and  the  broad  intermediate  space  be- 
tween the  marginal  and  median  striae 
smooth. 

N.  pohisticta  (G  rev. ) .  — Elliptical ;  striaa 
moniliform,  forming  a  narrow  marginal 
band,  separated  from  the  median  line  by 
an  irregularly  punctate,  lunate  inter- 
mediate space  ;  striae  25  in  '001".  Grev. 
I.  c.  f.  2.  Californian  guano.  Valve  mi- 
nute. Differs  from  N.  prcptexta  in  its 
smaller  size  and  far  less  rounded  ends. 

N.  Smitliii  (Breb.).  —  Elliptic,  with 
rounded  apices ;  striae  distinct,  21  in 
•001",  interrupted  on  each  side  of  the 
median  line  by  a  longitudinal  line  ;  the 
inner  series  narrow,  fainter.  =  N.  eUiptica, 
SD.  i.  p.  48,  pi.  17.  f.  152.  Marine. 
Europe.  The  outer  series  of  striae  is 
broad,  but  not  dilated  opposite  the 
central  nodule. 

N.  fusca  (Greg.).  —  Large,  elliptic- 
oblong,  with  broadly  roimded  ends; 
striae  coarsely  moniliform,  about  10  in 
•001",  divided  on  each  side  by  a  longi- 
tudinal line  into  two  series,  the  inner 
one  fainter.  =  iV.  Smitliii,  ^  fusca,  GD. 
p.  14,  pi.  1.  f.  15.  Marine.  Scotland. 
Differs  from  iV.  SmifJiii  in  its  much  larger 
size  and  more  distant  striae.  Nodule 
indefinite ;  median  smooth  space  narrow 
lanceolate. 

N.  iiitescens  (Greg.). — Small,  elliptic- 
lanceolate,  with  obtuse  apices;  striae 
obscurely  moniliform,  about  16  in  -001", 
converging  at  centre,  divided  on  each 


OF  THE  NAYICULE.i:. 


899 


side  by  a  longitudinal  line  into  two  series, 
reaching  the  median  line.  =  iV!  Smithii, 
y  nitescem,  GD.  p.  15,  pi.  1.  f.  16.  Ma- 
rine. Scotland.  Colourless  imder  a  low 
power;  median  line  linear,  nodide  de- 
finite. Distinguished  from  N.  Smithii  by- 
its  smaller  size,  the  characters  of  nodide 
and  median  line,  and  its  bright- white 
aspect, 

N.  quach'ifasciata  (E.).  —  Elliptic-ob- 
long, Avith  attenuated,  obtuse  ends  ) 
strise  20  in  1-1200",  di\'ided  on  each  side 
of  the  median  line  into  two  linear  series. 
EB.  1840.  =  Pinnularia  quadrifasciata, 
EM.  pi.  19.  f.  25-27;  N.  lineata,^J)on\im, 
MT.  vi.  p.  32,  pi.  3.  f.  17  ?  Marine.  Fossil, 
Greece  ;  recent,  Britain.  1-430".  Series 
of  striae  separated  by  a  naiTow  blank  line. 

N.  elliptica  (K.). — Elliptic  or  linear- 
elliptic,  vnih.  roimded  ends ;  striae  di- 
stinct, connivent,  27  in  -001",  divided 
into  two  series  on  each  side  the  median 
space  by  a  longitudinal  line.  =iV;  Par- 
mula,  KA.  p.  80;  N.  ovalis,  SD.  i.  p.  48, 
pi.  17.  f.  153.     Europe. 

N.  pygm(Ba  (K.). — Minute,  elliptic  or 
oblong-elliptic,  with  rounded  ends,  hya- 
line, with  very  faint,  close  striae,  and  a 
panduriform  blank  median  space.  KA. 
p.  77. =N,  mimitula,  SD.  i.  p.  48,  pi.  31. 
f.  274.  In  brackish  or  fresh  water. 
France,  England.  Although  the  striae, 
which  are  very  indistinct,  are  not  inter- 
rupted, yet  the  peculiar  form  of  its  me- 
dian space  shows  that  its  proper  position 
is  in  this  gToup. 

N.  cestiva  (Donkin). — Large,  narrow- 
elliptic,  with  rounded  ends ;  striae  fine, 
distinct,  costate  or  obscurely  moniliform, 
reaching  nearly  to  the  median  line, 
crossed  on  either  side  near  their  inner 
ends  bv  a  longitudinal  line.  TM.  vi. 
p.  32,  pi.  3.  f.  18.  Marine.  Northum- 
berland. This  beautiful  species  differs 
from  N.  Smithii  in  its  more  gracefully 
elliptical  figure,  in  its  costate  and  much 
finer  striae,  and  in  the  darker-brown 
colom*  when  mounted  in  balsam.  The 
dry  valve  is  pale-brown.     Donkin. 

N.  AUmaniana  (Greg.). — Small,  oval, 
with  subacute  apices  ;  costae  about  20  in 
•001",  somewhat  radiant,  nearly  reaching 
the  median  line,  divided  by  a  line  near 
to  and  concentric  with  the  margin.  = 
Pinmilaria  AUmaniana,  GD.  p.  16,  pi.  1. 
f.  21.  Marine.  Scotland.  The  marginal 
series  of  costae  narrow,  conspicuous, 
border-like ;  the  inner  one  fainter. 

2  t  Valves  linear,  with  dilated  centre 
and  ends. 

N.  Rahenhorstii  (Ralfs).  —  Elongated, 


slender,  gradually  dilated  at  centre  and 
broadly  rounded  ends ;  striae  fine,  short, 
divided  on  each  sid«  the  median  line  by 
a  naiTow,  blank,  longitudinal  line.  =  Pin- 
milaria interrupta,  Bab  D.  p.  44,  pi.  6. 
f.  3.  Italy.  Divided  by  two  constric- 
tions into  three  oblong  portions ;  the 
interrupting  line  undulated  like  the 
margins.  This  species  resembles  a  slen- 
der N.  nohilis  with  interrupted  striae. 

F.    Valves  with  capitate  or  rostrate  apices, 
t  Valves  inflated  or  ventricose. 

N.  Crux  (E.).  —  Cruciform,  with  di- 
verging costae,  which  do  not  reach  the 
median  line.  =  Pinnularia  Crux,  EM. 
pi.  12.  f.  37.  Asia,  Cassel.  This  species 
has  the  lateral  view  like  a  Biblarium,  but 
with  median  line  and  nodide. 

N.  Trochus  (E.).  —  With  strongly  in- 
flated middle,  and  obtuse,  rostrate  ends, 
longitudinally  striated.  Elnf.  p.  179, 
pi.  21.  f.  8.     Fossil.     Sweden.    1-860". 

N.  inflata  (K.)- — Minute  ;  with  much 
inflated  centre,  and  short,  obtuse,  beak- 
like ends  ;  strife  wanting  or  indistinct. 
KB.  p.  99,  pi.  3.  f.  36=iV:  Follis,  EM. 
several  figiu*es.  Fossil,  Sweden,  Santa 
Fiore ;  recent,  Europe. 

N.  amphisbcena  (Bory).  —  Inflated, 
elliptic,  with  capitate  or  conic  apices ; 
strife  close,  delicate.  E  Inf.  p.  178,  pi.  13. 
f.  7  ;  SD,  i.  p.  51,  pi.  17.  f.  147.  Common. 
Europe,  Asia,  Africa,  America.  (^t:i.  72 ; 
IX.  141.)  1-1700"  to  1-240".  Median 
nodide  orbicular.  The  Pinnularia  am- 
phisbcena,  EM.,  is  probably  a  state  of  this 
species  exhibiting  more  conspicuous 
striae. 

N.  Placenta  (E.). — Minute,  ventricose, 
roundish-elliptic,  with  a  nipple-like  pro- 
!  jection  at  each  apex,      EM.  pi.  33. 12. 
'  f.  23.     Oregon. 

N.  sphcerophora  (K.). — Elliptic-lance- 
olate, strongly  constricted  into  capitate 
or  conic  apices;  striae  wanting  or  in- 
distinct. KB.  p.  95,  pi.  4.  f.  17 ;  SD.  i. 
p.  52,  pi.  17.  f.  148.  Europe,  Asia.  Very 
similar  to  N.  amphisbccna^  but  it  is  less 
inflated,  and  it  appears  destitute  of  striae. 
According  to  Rabenhorst,  it  difliers  also 
bv  having  faint  longitudinal  lines. 
1^320". 

N.  hrevis  (Greg.).  —  Small,  elliptic, 
contracted  into  short,  broad,  mammiform 
ends ;  striae  fine,  about  35  in  -001", 
nearly  reaching  the  median  line,  shorter 
opposite  the  indefinite  central  nodule. 
GD.  p.  6,  pi.  1,  f,  4.  Scotland.  Professor 
Walker  Arnott  is  probably  correct  in 
uniting  this  to  N,  amphishcena. 
3m2 


900 


SYSTEMATIC  HISTOET  OF  THE  IXFUSOHIA. 


N.  tumens  (S.). — Inflated,  elliptic,  with 
the  ends  suddenly  contracted  into  short, 
obtuse  beaks ;  striae  indistinct,  36  in 
•001".  SD.  i.  p.  52,  pi.  17.  f.  150.  Brack- 
ish water.     England. 

N.  pusilla  (S.). — Small,  inflated,  ellip- 
tic, suddenly  contracted  into  short,  conic 
beaks ;  stii?e  distinct,  punctate,  radiant, 
26  in  -001".  SD.  i.  p.  52,  pi.  17.  f.  52. 
=iN.  gastroides,  Greg.  MJ.  iii.  p.  40,  pi.  4. 
f.  17.  Brackish  water  ?  Britain.  Prof. 
Gregory  distino-uished  his  N.  gastroides 
from  this  species  by  its  stouter  habit, 
larger  size,  and  having  a  brown  colour 
even  in  balsam;  but  we  unite  them  as 
Professor  Smith  has  done,  being  imwill- 
ing  to  add  another  doubtful  species  to 
this  group,  which  we  believe  is  already 
too  numerous. 

N,  Anglica  (Ralfs). — Minute,  elliptic, 
suddenly  constricted  beneath  the  round- 
ish capitate  ends;  striae  very  distinct, 
punctate,  radiate,  reaching  the  median 
Ime,  24  in  -001".  =  N.  tumida,  SD.  i. 
p.  53,  pi.  17.  f.  146. 

N.  Carassius  (E.).  —  Small,  inflated, 
broadly  lanceolate,  with  the  ends  sud- 
denly contracted  into  short,  conical 
beaks  ;  striae  wanting  or  indistinct.  EA. 
p.  130,  pi.  2.  2.  f.  11.  France,  America. 
Is  smaller  than  N.  amjMshfena. 

N.  capitaia  (E.).  —  Minute,  ^^dth  in- 
flated centre,  and  short,  obtuse,  beak- 
like ends;  striae  diverging,  10 in  1-1200". 
E  Inf.  p.  179,  pi.  13.  f.  20.  =  Pinmdaria 
capitaia,  EM.  pi.  35  a.  1.  f.  4.  Europe, 
Asia,  Australia,  America.  1-1150"  to 
1-576". 

N.  Seinen  (E.).  —  SmaU,  elliptic-ob- 
long, slightly  contracted  into  the  broad, 
obtuse  ends ;  striae  obsolete  or  apparent. 
EA.  pi.  4.  2.  f.  8 ;  in  EM.  manv  hgures  ; 
SD.  i.  p.  50,  pi.  16.  f.  141.  i3,'^stri£e  di- 
stinct, =  Pinmdaria  Semen,  EM.  Europe, 
Asia,  Africa,  America, 

N.  cequalis  (E.,  K.). — Inflated,  eUiptic- 
lanceolate,  suddenly  contracted  at  the 
ends  into  nipple-like  points ;  striae  fine. 
KSA.  p.  77.  =  Pinnularia  (eqiialis,  EA. 
131 ;  EM.  many  %ures.  Europe.  Lough 
Mourne  deposit,  Iceland. 

N.  diomj)Iiala  (E.).  —  Striated,  short, 
broadly  lanceolate,  suddenly  conti^acted 
into  obtuse  beaks ;  median  nodule  trans- 
verse, divided  bv  a  longitudinal  line  into 
two  parts.  EA.  p.  132,  pi.  3.  7.  f.  25. 
America. 

N.  Gastrum  (E.,  K.). — Small,  striated, 
inflated,  elliptic,  contracted  at  the  ends 
into  short  conical  beaks ;  striae  radiant. 
KB.  p.  94,  pi.  28.  f.  56.  =  Pinmdaria 
Gastrum,    EM.    several  figures;     Pi7i- 


nularia  Placentida,  EM.  several  figures. 
Asia,  Africa,  America. 

N.  hirostrata  (Greg.).  —  Ventricose, 
elliptic-oblong,  with  shortly  rostrate 
apices ;  striae  tine,  close,  radiant,  reaching 
nearly  to  the  median  line.  M  J.  iii.  p.  40, 
pi.  4.  f.  5.     Scotland. 

N.  tceniata  (E.).  —  Small,  inflated, 
elliptic,  suddenly  contracted  into  minute, 
rounded,  conical  beaks ;  pinnides  strong, 
forming  a  narrow  marginal  border.  = 
Pinmdaria  tceniata,  EM.  pi.  39.  f.  95. 
The  pinnules  separated  from  the  median 
line  by  a  broad  blank  space.  Perhaps  a 
Mastogloia.  (xv.  15.) 

N.  hiceps  (E.).  —  Small,  turgid,  lance- 
olate, slightly  constricted  into  obtuse, 
conical  apices ;  striae  wanting-  or  indi- 
stinct. EA.  p.  130 ;  EM.  many  tigm-es. 
Em*ope,  Africa,  America.  Rather  more 
slender  than  N.  amplxishcena. 

N.  crassula  (Niigeli).  —  Smooth,  ellip- 
tic, Tvdth  capitate  apices ;  front  view 
broadlv  linear,  trmicate.  1-720".  KSA. 
p.  890."^     S\\dtzerland. 

N.  scidpta,  EM.pl.  10.  1.  £5.  Bohe- 
mia, Asia,  America.  Ventricose,  sud- 
denly tapering  into  short,  broad,  obtuse 
beaks,  the  median  line  interrupted  by 
the  indefinite  nodule,  which  extends  on 
one  side  in  a  semicrucial  smooth  band ; 
the  rest  of  the  surface  granidated.  Front 
view  linear,  mtli  rounded  angles  and 
gibbous  sides. 

N.  signata  (E.).  —  Minute,  inflated, 
prolonged  into  naiTOw  beaks ;  striae 
radiant,  reaching  the  median  line,  the 
six  central  ones  stronger.  =  Pinmdaria 
signata,  EM.  pi.  34.  6  a.  f.  7.     Florida. 

N.  RosteJlum  (S.). — Small,  ventricose, 
oval,  with  the  apices  produced  into  point- 
like beaks ;  striae  indistinct,  80  in  -001". 
SBD.  ii.  p.  93  =  A^  apimlata,  Greg.  MJ. 
iv.  pi.  1.  f.  13.     Britain. 

2  t  Valves  lanceolate. 

N.  Crassinervia  (B.). — Minute,  lance- 
olate, Tvith  shortly  rostrate  apices ;  striae 
wanting  or  indistinct.  SD.  i.  p.  47,  pi.  31. 
f.  271.     France,  Britain. 

N.  rhjncJiocephala  (K.).  —  Slender, 
lanceolate,  with  longly  rostrate  apices ; 
striae  wanting  or  obscure.  KB.  p.  152, 
pi.  30.  f.  35 ;  SBD.  p.  47,  pi.  16.  f.  132. 
Europe.  Is  longer  and  more  slender  than 
N.  cryptocephala,  with  more  produced 
apices,     (vii.  68.) 

N.  le2itorhgnclms(E.).—^mQi\,  smooth, 
linear-lanceolate,  with  straight,  subacute, 
longly  rostrate  apices.  EA.  p.  130. 
Mexico.  Akin  to  N.  dirhynchus,  but 
with  lonorer  beaks. 


OF  XnE  NAVICULE^. 


901 


N.  leptocephala  (Rab.). — Small,  lance- 
olate, with  eloug-ated,  slender,  obtuse, 
somewhat  clavate  beaks  ;  striae  wanting- 
or  indistinct.  Eab  D.  p.  39,  pi.  6.  f.  69. 
Em-ope. 

N.  exiUs  (K.). — Very  minute,  smooth, 
lanceolate,  wdth  produced,  obtuse  apices. 
KB.  p.  95,  pi.  4.  f.  6.     Germany. 

N.  rostrata  (E.).  —  Finely  punctated, 
broadly  lanceolate,  almost  rhomboid, 
rapidly  tapering  into  acute  beaks  ;  cen- 
tral nodule  large.  EB.  1840,  p.  18  ;  KB. 
p.  94,  pi.  3.  f.  45.  Fossil.  Santa  Fiore. 
1-216".  Front  \dew  linear,  with  trim- 
cate  apices. 

N.  Charontls  (E.). — Elongated,  smooth, 
oblong-lanceolate,  with  the  ends  con- 
tracted into  conic  beaks.  EB.  184-5, 
p.  239 ;  EM.  pi.  35.  bb.  f.  12.  Fom-  times 
as  long  as  broad. 

N.  Otrantina  (Rab.).  —  Oblong-lance- 
olate, with  rounded,  slightly  contracted 
ends.     Rab  D.  p.  44,  pl."'6.  f.  42. 

N.  dirhynchus  (E.). — Small,  narrow- 
lanceolate,  vnXh.  conic,  rostrate  apices ; 
strite  wanting  or  indistinct.  EA.  p.  130, 
pi.  3.  1.  f.  11.     Falaise,  Mexico. 

N.  Garganica  (Rab.).  — Minute,  lan- 
ceolate, suddenly  contracted  into  short, 
thick,  obtuse  apices ;  striae  distinct,  ob- 
lique, reaching  the  median  line,  six  near 
the  central  nodide  stouter  than  the  rest. 
=Pinmdaria  Garganica,  Rab  D.  p.  44, 
pi.  6.  f.  41.     Italy.  ^ 

N.  amphiceros  (K.). — Minute,  broadly 
lanceolate,  with  produced,  rostrate  apices, 
and  fine  striae.  KB.  p.  95,  pi.  3.  f.  39. 
Germany,  Asia. 

^.stelligera  (E.,  K.). — Rhomboid-lan- 
ceolate, with  the  apices  suddenly  atte- 
nuated into  obtuse  beaks ;  the  very  fine 
punctated  pinnules  distinctly  radiating 
from  the  orbicular,  smooth  umbilical 
space.  KA.  p.  70.  =Puinulanasfenigera, 
EB.  1845,  p.  364.     Marine.     India.' 

N.  Petersii  (E.,  K.) — Dilated,  large  at 
each  end,  suddenly  attenuated  into  a  very 
short  beak  j  median  line  double,  with  a 
naiTow,  longitudinal  umbilical  space ; 
pinnules  very  fine.  KA.  p.  70.  =Pi?mu- 
laria  Petersii,  EB.  1845,  p.  304.  Mouth 
of  the  river  Tagus. 

N.  guttulifera  (Rab.). — Minute,  slen- 
der, acicular,  with  a  glass-like  globe  at 
each  apex.  RD.  p.  40,  pi.  6.  f.  74.  South 
Persia. 

N.  pachycephala  (Rab.).  —  Minute, 
slender-lanceolate,  constricted  beneath 
the  capitate  apices ;  striae  converging ; 
central  nodule  stout,  teiiuinal  ones  ob- 
solete. =  Pinmdaria  pacliycepliala,  RD. 
p.  43,  pi.  6.  f.  40.     Italy. 


N.  cincta.  =  Pinmdaria  cincta,  EM. 
pi.  10.  2.  f.  6.  Bohemia.  This  species 
is  figured  as  minute,  lanceolate,  yvith. 
obtuse  apices ;  striee  oblique,  those  oppo- 
site the  centi-al  nodule  radiant  and  stouter 
than  the  others. 

_  N.  Gregorii  (Ralfs).  —  Small,  narrow 
linear-lanceolate,  contracted  at  the  ends 
into  miuute  beaks ;  stride  distant,  parallel, 
scarcely  reaching  the  median  line.  = 
Pinmdaria  apiculata,  Greg.  MJ.  iii.  p.  41, 
pi.  4.  f.  21.'    Scotland. 

N.  angustata  (S.).  —  Minute,  narrow- 
lanceolate,  constricted  beneath  the  capi- 
tate apices ;  stiiae  indistinct,  45  in  -001". 
SD.  i.  p.  52,  pi.  17.  f.  156.  =iy  dicephala  /3, 
KA.  p.  76?  Britain,  Falaise.  Front 
view  narrow-linear. 

N.  cryptocephala  (K.). — Very  minute, 
lanceolate,  with  globose,  capitate  apices ; 
striae  wanting  or  indistinct.  KB.  p.  95, 
pi.  3.  £  20.     Europe. 

N.  Veneta  (K.). — Very  minute,  lan- 
ceolate, nither  broad,  with  produced, 
slightly  obtuse  apices;  striae  wanting 
or  indistinct.  KB.  p.  95,  pi.  30.  f.  76. 
Brackish  water,  Venice.  Resembles  N. 
cryptocephala,  but  is  shorter  and  broader. 

N.  Fusidium  (E.).  —  Narrow-lanceo- 
late, distinctly  but  slightly  constricted 
beneath  the  capitate  apices.  EM.  pi.  5.  3. 
f.  4.     America,  Asia. 

N.  Jeptostylus  (E.).  —  Lateral  view 
tm-gid-lanceolate,  suddenly  tapering  into 
short  beaks  "udth  capitate  apices.  =  N. 
Platalea,  EM.  pi.  15  a.  f.  42. 

N,  cmiphirrhina  (F,.)  =  Pinnulana  am- 
phirrhina,  EM.  pi.  15  a.  f.  20.  Lough 
Mom-ne  deposit,  Japan,  America.  Ehr- 
enberg  figm-es  this  species  as  inflated- 
lanceolate,  rapidly  tapering  into  subacute 
beaks ;  striae  parallel. 

1^.  amjyhirhynchus  (E.). —  Small;  tm'- 
gid-lanceolate,  suddenly  constricted  at 
the  ends  into  short,  subcapitate  beaks; 
striae  indistinct  or  wanting,  EA.  pi.  3.  1. 
f.  10 ;  KA.  p.  76.  Em-ope,  Asia,  Aus- 
ti-alia,  Africa,  America,    (xn.  6.) 

N.  amjyhistylus  (E.,  K.). — Elongated 
bacillar,  with  tiu'gid  middle,  attenu- 
ated, filiform,  obtuse  apices,  and  deli- 
cate pinnules.  KSA.  p.  7 o.=  Pinmdaria 
amphistyhis,  EB.  1845,  p.  79.  Fossil. 
Oregon.     1-372". 

N.  ordinata  (Breb.). — Minute,  smooth, 
connected  in  a  parallel  manner  into 
short,  fragile  filaments ;  valves  slender- 
lanceolate,  conti'acted  at  the  ends  into 
short,  often  capitate  beaks.  Breb.  =  iV. 
aponina  /3,  ELA.  p.  69.     Falaise. 

N.  euryccphala  (Rab.).  —  Large,  ro- 
bust, oblong,  slightly  contracted  at  the 


902 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


ends  into  very  short  and  broad,  truncate 
Leaks.  Rab  D.  p.  40,  pL  6.  f.  70.  Ger- 
luany.  Median  line  and  nodide  strongly 
developed,  liesembles  Stauroneis  platy- 
stoina,  but  with  a  roimded,  not  trans- 
verse median  nodide. 

3t  Valves  linear. 

N.  dicephala  (E.).  —  Elongated  linear, 
constricted  at  the  ends  into  capitate  or 
broadly  conical  beaks;  striaj  either  ob- 
ycure  or  distinct,  19  in  1-1200".  =  iVrti7- 
culu  and  Pinmdaria  dicephala,  EM.  many 
ligures ;  Pimmlaria  biceps,  Greg.  M J.  iv. 
pi.  1.  f.  28  ?  Common.  Em-ope,  Asia, 
Africa,  America.     1-860"  to  1-480". 

N.  producta  (S.). — Linear,  abruptly 
contracted  at  the  ends  into  short,  obtuse 
beaks;  strict  faint,  42  to  48  in  -001". 
SD.  i.  p.  51,  pi.  17.  f.  144.  =  N.  amphi- 
n/uclms,  SD.  i.  p.  51^  pi.  16.  f.  142.  Britain. 

N.  birostris  (E.). — Elongated  narrow- 
linear,  suddenly  contracted  at  the  ends 
into  conical  apices ;  striee  distinct,  close, 
parallel.  =  Pinmdaria  birostris,  EM.  pi. 
15  A.  f.  24.  Fossil,  Lough  Mourne  de- 
posit ;  Sweden.  This  form  seems  scarcely 
to  differ  from  iV.  dicephala,  except  in 
having  slenderer  frustules. 

N.  (fracillima  (Greg.). — Slender,  nar- 
row-linear, constricted  beneath  the  capi- 
tate apices ;  costie  hue,  27  in  -001",  not 
reaching  the  median  line.  =  Pinmdaria 
(/raciUima,  MJ.  iv.  p.  9,  pi.  1.  f.  31 ;  SD. 
ii.  p.  95 ;  Pinmdaria  tennis,  MJ.  ii.  pi.  4. 
f.  9  ?     Britain. 

I^.  linearis  (Greg.). — Minute,  narrow- 
linear,  constricted  beneath  the  subcapi- 
tate  ends ;  costse  very  fine,  about  40  in 
•001",  parallel,  reaching  the  median  line. 
=  Pinmdaria  linearis,  MJ.  iv.  p.  8,  pi.  1. 
f.  29.     Scotland. 

N.  subcapifata  (Greg.). — Minute,  nar- 
row-linear, constricted  beneath  the  capi- 
tate ends  ;  striiB  subdistant,  conspicuous, 
short.  =  Pinmdaria  subcajjitata,  MJ.  iv. 
p.  9,  pi.  1.  f.  30.     Scotland. 

N.  Elyinensis  (Greg.). — Minute,  linear, 
constricted  beneath  the  subquadrate 
capitate  ends;  strise  fine,  about  30  in 
•001",  slightly  oblique,  reaching  the 
median  line.  =  Pinmdaria  EJqinensis,  MJ. 
iv.  p.  9,  pi.  1.  f.  33.     Scotland. 

N.  linqn'da  (Perty).  —  Rather  large, 
striated,  broadly  linear-oblong,  suddenly 
contracted  at  the  ends  into  short,  broad, 
obtuse  beaks.  Perty,  Mic.  Org.  of  Alps, 
p.  204,  pi.  17.  f.  9.  Alps.  Front  view 
linear,  with  truncate  ends;  striae  10  to 
11  in  1-1200". 


N.  Pisciculus  (E.,  K.).  —  Elongated, 
slender,  striated,  narrow-linear,  slightly 
contracted  at  the  ends  into  conic  beaks ; 
striae  very  delicate.  KA.  p.  75.  =  Pin- 
nularia  Pisciculus,  EA.  pi.  2.  1.  f.  30. 
Cayenne,  India,  Falaise. 

N.  limbata  (E.). — Small,  linear,  each 
end  suddenly  contracted  into  a  short, 
broad,  trimcate  beak,  and  a  wide  border 
appearing  within.  EA.  p.  130,  pi.  1.  2. 
f.  16.     Chili. 

N.  lomjiceps  (Greg.).  —  Minute,  nar- 
row-linear, with  the  ends  contracted 
into  short,  obtuse  points;  nodule  inde- 
tinite ;  strite  wanting  or  inconspicuous. 
MJ.  iv.  p.  8,  pi.  1.  f.  27.     Scotland. 

N.  ajfinis  (E.). — Small,  linear-oblong, 
with  the  ends  suddenly  contracted  into 
short,  broad,  obtuse  beaks ;  strias  waiit- 
iug  or  indistinct.  EA.  p.  129,  pi.  2.  2.  f.7; 
SD,  i.  p,50,  pi.  16.  f.  143.  Very  common. 
Ehrenberg  gives  upwards  of  seventv 
habitats,  (xii.  32.)  1-570"  to  1-420". 
Resembles  N.  dicephala. 

N.  dubia  (E.).  —  Small,  linear-lanceo- 
late, with  the  ends  suddenly  contracted 
into  conic  beaks ;  strise  wanting  or  in- 
distinct. EA.  p.  130,  pi.  2.  2.  f.  8.  Asia, 
Australia,  Africa,  America.  Akin  to 
N.  ctjfinis. 

N.  ambicjua  (E,).  —  Small,  oblong, 
somewhat  inflated,  with  the  ends  sud- 
denly contracted  into  short,  conic  beaks ; 
strine  wanting  or  indistinct.  EA.  pi,  2,  2. 
f.  9;  EM,  pi,  15  b,  f.  15.  America,  Aus- 
tralia, Lough  Mourne  deposit.  Re- 
sembles N.  affinis  and  N.  dicephala. 

N.  rosfellata  (K.).  —  Minute,  striated, 
linear-oblong,  with  elongated,  rostrate, 
acute  apices.  KB.  p.  95,  pi.  3.  f.  65. 
Wangeroog-e. 

N.  columnar  is  (E.). — Large,  elongated, 
broadly  linear,  suddenly  contracted  into 
short,  very  broad,  rounded  ends,  and 
marked  by  numerous  longitudinal  lines. 
EM.  pi.  14.  f.  23.     Berlin. 

N.  ampliata,  EM.  pi.  17.  2.  f.  7,  & 
pi.  15  A.  f.  32.  Finland,  Siberia,  Lough 
Mourne  deposit.  Ehrenberg's  figures  re- 
present this  species  as  large,  smooth, 
iDroadly  linear,  suddenly  contracted  at 
the  ends  into  broad,  romided,  mammi- 
form beaks. 

N.  Vespa  (R.). — Small,  linear-oblong, 
constricted  beneath  the  capitate  apices  ; 
nodules  minute ;  strife  parallel,  close, 
nearly  reaching  the  median  line.  =P<Vi- 
mdaria  Vespa,  EM.  pi.  33.  5.  f.  9.  Asia, 
Africa,  America. 

N.  incurca  (Greg.).  —  Small,  linear, 
with  slightly  smuated  sides ;  ends  con- 
tracted into  short  trimcate  bealis  ;  stria) 


OF  THE  KAYICULE.E. 


903 


wanting  or  inconspicuous.  MJ.  iv.  p.  8, 
pi.  1.  f.'2G.     Scotland. 

N.  apiculata  (Breb.). — Striated,  linear, 
suddenly  attenuated  at  eacli  end  into  a 
short  apicuhis ;  front  \-iew  broad,  qua- 
drate, with  striated  lateral  margins ; 
stride  strong,  14  in  -001",  nearly  reaching 
the  median  line.  Breb  DC.  p.  16,  pi.  1. 
f.  20.  =  Pifmulana  rosteUata,  GDC.  p.  10, 
pi.  1.  f.  20.  Marine.  Europe.  Striae 
somewhat  radiant.  The  frustules  are 
much  compressed,  and  very  similar  in 
the  front  view  to  those  of  N.  retusa. 

4 1  Valves  subquadrate  or  elliptical,  with 

conical  terminal  points. 

N.  lacustris  (Greg.).  —  Small,  oblong 
or  subquadrate,  with  acute  or  shortly 
rostrate  apices  ;  striae  fine,  distinct, 
slightly  oblique,  nearly  reaching  the 
median  line,  28  or  30  in  -001".  MJ.  iv. 
p.  6,  pi.  1.  f.  2.3._  Scotland.  The  only 
species  ^^-itli  which  this  could  be  con- 
founded is  N.Jirma',  but  the  latter  is 
longer  and  larger,  of  a  brown  colour, 
with  finer,  less  conspicuous,  and  parallel 
striae. 

N.  humerosa  (Breb.). — Siriated,  sub- 
quadrate  ;  ends  trimcate,  with  a  minute, 
conic  central  point;  stride  fine,  monili- 
form,  24  in  -001",  radiant,  reaching 
nearly  to  the  median  line,  shorter  oppo- 
site the  roundish  umbilical  space.  SD. 
ii.  p.  94.  =  N.  quadrata,  Greg.  TM.  iv. 
p.  41,  pi.  5.  f.  5.  Marine.  Em^ope.  Ac- 
cording to  Dr.  Donkin,  the  dry  valve, 
under  a  low  power,  is  hyaline  and 
colomiess. 

'^ .  (/ramdata  (Breb.). — Striated,  rather 
large,  elliptic  or  subquadi-ate ;  ends  with 
a  conic  central  point ;  striae  conspi- 
cuously monilifomi,  16  in  -001",  radiant, 
reaching  nearlv  to  the  median  line. 
Donkin,  TM.  yi.  pi.  3.  f.  19.  Marine. 
Em-ope.  Distinguished  from  N.  hume- 
rosa by  its  more  distant  and  coarsely 
granulated  striae.  "  Dry  valve  of  a  dull 
bluish  colour,  inclining  to  pm-ple " 
(Donkin). 

N.  compacia  (Grev.).  —  Small,  sub- 
quadrate,  with  slightly  concave  sides, 
rounded  shoulders,  and  the  median  line 
prolonged  into  conic  points  ;  striae  faint, 

42  in  -001",  reaching  nearly  to  the  me- 
dian line.  Greg.  MJ.  v.  p.  11,  pi.  3.  f.  8. 
Marine.  Not  ujicommon.  The  striae  are 
nearly  parallel.  A  species  well  marked 
by  its  quadrate  shape. 

N.  hdissima  (Greg.). — Broadly  elliptic, 
with  slightly  produced  mammiform 
apices ;  striae  distinct,  finely  monilifomi, 


radiant,  nearly  reachhig  the  median  line, 
shorter,  and  leaving  an  orbicular  hyaline 
space  round  the  central  nodide,  TM.  iv. 
p.  40,  pi.  5.  f.  4.  Marine.  Britain, 
(vii.  70.)  Distinguished  from  N.  (jm- 
nidata  by  its  strav\"  or  light-brown  colour 
in  balsam,  and  less  conspicuous  gianules. 

N.  Barclayana  (Greg.).  —  Elliptic- 
oblong,  with  minute,  conic  apices  ;  striae 
about  38  in  -001",  finely  monilifomi, 
short,  forming  a  naiTow  marginal  band, 
and  enclosing  a  large,  lanceolate  smooth 
median  space.  GDC.  p.  8,  pi.  1.  f.  9. 
Marine.  Britain.  The  marginal  striated 
band  is  of  nearly  uniform  breadth,  ex- 
cept near  the  base,  where  it  becomes 
naiTower. 

N.  marma(^2i!d^. — Oval,  with  slightly 
produced  conic  apices,  and  33  distinct, 
moniliform,  radiant  stiiie  in  -001",  which 
reach  the  median  line.  =  N.  punctidata, 
SD.  p.  52,  pi.  16.  f.  151.  Marine.  Eng- 
land. 

Is",  producta  (Ralfs). — Oblong-elliptic, 
much  constricted  at  each  end,  as  if  ob- 
tusely mucronate  j  surface  elegantly 
marked  by  decussating  punctated  lines ; 
puncta  in  quincunx.  =  iV".  decussafa,  EB. 
1843,  p.  256.     Habit  of  N.  Amphkhcena. 

G.   Vcdves  lanceolate  or  rhomboid. 

N.  rhomhoides  (E.).  —  Rhomboid-lan- 
ceolate, with  subacute  apices  and  85, 
verv  faint,  parallel  stride  in  -001".  EA. 
pi.  3.  1.  f.  15  ;  SBD.  i.  p.  46,  pi.  16. 
f.  129.     Mexico,  Em'ope,  Australia. 

N.  rhomhica  (Greg.).  —  Rhomboid- 
lanceolate,  vnXh.  A'ery  tine  but  distinct 
striae,  45  in  -001",  reaching  the  median 
line.  MJ.  iii.  p.  40,  pi.  3.  f.  16 ;  TM.  iv. 
p.  38,  pi.  5.  f.  1.  Marine.  Scotland, 
(vn.  71.)  According  to  Professor  Gre- 
gory, N.  rhomhica  is  distinguished  fi*om 
N.  rhomhoides  by  the  difterent  appear- 
ance of  its  median  line  and  central 
nodide,  as  well  as  by  its  distinct  striae. 

N.  rliomhea  (E.). — Broadly  rhomboid- 
lanceolate,  with  acute  apices,  and  delicate 
longitudinal  lines  on  each  side;  trans- 
verse striae  wanting  or  indistinct.  EA. 
p.  131,  pi.  3.  7.  f.  27.  Mexico.  1-480" 
to  1-360". 

N.  Bemeraroi  (E.). — Smooth,  rhom- 
boid, tumid,  strongly  tapering  into  acute, 
subrostrate  apices.  EB.  1845,  p.  79. 
Demerara.  1-576".  ^' Distinguished  from 
N.  rhomhea  only  by  its  subrostrate  ends  " 
(Rabenhorst). 

N.  decussata  (E.,  K.).  —  Rhomboid- 
lanceolate,  A\T.th  subacute  apices,  an  ob- 
solete  umbilical   space,  and  very  fine, 


904 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


decussating,  punctated  striae.  ILA..  p.  70. 
=  Pinnularia  decusscda,  EB.  1845,  p.  364. 
Marine.     India. 

N.  Indica  (E.).  —  Rliomboid-lanceo- 
late,  with  somewhat  obtuse  apices,  a 
small  umbilicus,  and  thick- set,  fine,  lon- 
gitudinal, pmictated  lines  (8  on  each 
side).  EB.  1845,  p.  363.  Marine.  India. 
Somewhat  resembles  N.  decussata. 

N.  ?  aspenda  (E.,  K.). — Tm-gid,  short, 
rhomboid-lanceolate,  six-angled,  rough 
with  punctated  stride ;  umbilicus  subor- 
bicular;  the  longitudinal  median  space 
much  dilated  near  the  umbilicus.  KA. 
•^.  71.  =  Pinmdaria?  aspenda,  EB.  1845, 
p.  364.     Marine.     India. 

N.  LiheUus  (Greg.).  —  Rhomboid-lan- 
ceolate, with  obtuse  ends;  strias  fine, 
uniform,  about  60  in  -001",  reaching  the 
median  line ;  front  view  broadly  linear, 
with  the  central  portion  longitudinally 
lined.  GDC.p.57,pl.6.  f.  101.  Scotland. 
In  form  it  much  resembles  N.  rliom- 
hica,  but  is  more  obtuse  and  broader, 
with  imiform  striae.  Professor  Walker- 
Arnott  regards  this  species  as  escaped 
frustules  of  Schizoiie?na  Grevillii, — an  opi- 
nion, indeed,  shared  by  Professor  Gre- 
goiy  himself. 

N.  suhtUis  (Greg.). — Elongated,  trans- 
lucent, very  slender,  rhomboid-lanceo- 
late, with  a  minute,  definite  nodule; 
costse  about  30  in  -001",  parallel,  reach- 
ing the  median  \mQ.=Pinmdana  suhtilis, 
GDC.  p.  16,  pi.  1.  f.  19.  Marine.  Scot- 
land. 

N.  hmceolata  (Ag.,  K.).  —  Minute, 
narrow-lanceolate,  with  44  indistinct, 
parallel  strict  in  -001".  KB.  p.  94,  pi.  28. 
f.  38 ;  SD.  i.  p.  46,  pi.  31.  f.  272.  Europe, 
America. 

N.  serians  (K.).  —  Small,  lanceolate, 
with  fine  longitudinal  lines,  and  subacute 
apices ;  front  view  broadly  linear.  KB. 
p.  92,  pi.  28.  f.  43;  SD.  i.  p.  47,  pi.  16. 
f.  130.  =  N.  lineoJata,  EM.  several  figures. 
Em-ope,  Asia,  Australia,  Africa,  Ame- 
rica. 1-288".  Frustides  frequently  co- 
hering. 

I^.  Suhda  (K.). — Elongated,  slender, 
narrow-lanceolate,  with  tapering,  sub- 
acute apices,  and  fine  longitudinal  lines. 
KB.  p.  91,  pi.  30.  f.  19.  Marine.  Europe. 

N.  tenella  (Breb.).  —  Minute,  smooth, 
very  narrow  -  lanceolate,  with  acute 
apices ;  front  view  linear,  slightly  con- 
stricted at  the  middle.  KA.p.  74.  Europe. 

N.  atu2)hioxi/s  (E.). — Elongated,  nar- 
row-lanceolate, with  acute  apices ;  striae 
indistinct  or  wanting.  EA.  pi.  1.  2.  f.  8 ; 
EM.  many  figures.  Europe,  Asia,  Aus- 
tralia, Africa,  America,  Lough  Mourne 


deposit.  More  slender  than  N.  gracUis. 
Front  view  narrow-linear. 

N.  Cari  (E.). — Minute,  smooth,  lance- 
olate, slender,  acute  at  both  sides,  with  a 
circular  median  nodule.  EI.  p.  179 ;  EM. 
pi.  12.  f.  20.     FossiL     Cassel.     1-1150". 

N.  oxyplnjllum  (K.). — Pellucid,  glassy, 
smooth,  slender -lanceolate,  gradually 
taperino-  to  the  acute  apices ;  median 
nodule  obsolete.  KB.  p.  92,  pi.  30.  f.  17. 
Marine.     Near  Flinsbm-g. 

N.  velox  (K.).  —  Minute,  smooth, 
broadly  or  oblong  lanceolate,  with  acute 
apices.  KB.  p.  91,  pi.  3.  f.  66.  =  A:  oh- 
lou(ja,  EA.  pi.  3.  1.  f.  14.  Wangerooge, 
Mexico. 

N.  apoyuna  (K.).  —  Minute,  smooth, 
slender-lanceolate,  \A\h.  acute,  subros- 
trate  ends.  KB.  p.  91,  pi.  4.  f.  1.  Eiu'ope. 
Front  view  narrow-linear. 

N.  Cesatii  (Rab.).  —  Minute,  smooth, 
slender-lanceolate  ;  front  view  linear, 
with  rounded  ends.  Rab  D.  p.  39,  pi.  6. 
f.  89.  Piedmont.  Very  like  N.  aj)oninay 
but  more  slender  in  the  lateral,  and 
broader  in  the  front  view. 

N.  digito-radiata  (Greg.). — Small,  ob- 
long-lanceolate, with  obtuse  ends ;  striae 
fine,  distinct,  about  25  in  -001",  reaching 
the  median  line,  those  near  the  central 
nodule  more  distinct  and  hioiily  radiant. 
=  Pinnularia  digito-radiata,^!^ .  iv.  p.  9, 
pi.  1.  f.  32.     Scotland. 

N.  Solaris  (Greg.).  —  Elongated,  nar- 
row-lanceolate, with  obtuse  ends ;  striae 
fine,  very  distinct,  36  in  '001",  oblique, 
radiant,  and  shorter  opposite  the  inde- 
finite central  nodule.  TM.  iv.  p.  43, 
pi.  5.  f.  10.  Marine.  Scotland.  Colour 
brown ;  striae  so  highly  radiant  round 
the  central  blank  spot  as  to  present  the 
appearance  of  a  smi  with  rays.  It  is 
longer  than  N.  radiosa,  with  finer  and 
more  inclined  striae. 

N.  Mediterranea  (K.). — Minute,  nar- 
row-lanceolate, with  obtuse  apices  and 
20  striae  in  1-1200";  fr-ont  view  strictly 
linear,  truncate.  KB.  p.  93,  pi.  3.  f.  17. 
Marine.     Em-ope.     1-1200". 

^.pundulata,^'M.  pi.  15  a.  f.34,B.f.  13, 
14.  Lough  Mom-ne  deposit,  Sweden, 
Africa.  Ehrenberg  figures  this  species 
as  rhomboid-lanceolate,  with  longitu- 
dinal, parallel,  dotted  lines. 

N.  appendiculata  (Ag.,  K.). — Minute, 
lanceolate,  with  slightly  turgid  middle 
and  subrostrate  obtuse  ends.  KB.  p.  93, 
pi.  3.  f.  2^.=Frustulia  and  Cymhella  ap- 
pendicidata,  Ag.  Europe.  Front  view 
linear,  with  truncate  ends.  In  the  lateral 
view  the  apices  are  somewhat  produced, 
but  scarcely  rostrate. 


OF  THE  NAVICULEJ;. 


005 


N.  ohtusa  (E.).  —  Small,  oblong-lan- 
ceolate, with  obtuse,  rounded  apices. 
EA.  p.  131,  North  America,  Asia, 
Africa.  Kiitzing  thinks  it  probably 
identical  with  N.  appendiculata. 

N.  injlexa  (Greg.). — Small,  lanceolate, 
with  subacute  apices;  costfe  conspi- 
cuous, 26  in  -001",  highly  radiant,  nearly 
reaching  the  median  line,  except  oppo- 
site the  central  nodule,  where  they  are 
short,  leaving  a  large,  roundish  blank 
space.  =Pinm(laria  b^exa,  TM.  iv.  p.  48, 
pi.  5.  f.  20.  Scotland.  Beneath  each 
apex  is  a  strong,  dark  cross-bar,  pro- 
bably caused  by  a  depression,  Greg. 

N.  fortis  (Greg.).  —  Small,  oblong- 
lanceolate  or  somewhat  rhomboid,  \\-ith 
obtuse  apices ;  costae  conspicuous,  16  in 
•001",  not  reaching  the  median  line, 
gradually  shorter  and  more  radiant  near 
the  central  nodide.  =  Pinnularia  fortis, 
TM.  iv.  p.  47,  pi.  5.  f.  19.  Scotland. 
Tm-gid ;  costse  prominent,  so  as  to  appear 
more  distant  than  they  actually  are. 

N.  mutica(K.). — Very  minute,  smooth, 
turgid-lanceolate,  -udth  distinct  median 
and  terminal  nodides.  KB.  p.  93,  pi.  3. 
f.  32.     Wangerooge.     1-1560". 

N.  Jurgensii  (K.).  —  Minute,  smooth, 
turgid  or  oblong-lanceolate,  with  obtuse 
apices  and  obsolete  median  nodide ;  front 
view  broadlv  linear,  with  truncate  ends. 
KB.  p.  93,  pi.  3.  f.  8.  Jsland  of  Wan- 
gerooge, Germany.     1-720". 

l>s.  viridula  (K.).  —  Small,  lanceolate, 
with  obtuse,  slightly  produced  apices; 
strise  wanting  or  indistinct.  KB.  p.  91, 
pi.  4.  f.  10.  15.     Europe. 

N.  carinata  (E.).  —  Large,  lanceolate ; 
front  view  linear,  with  a  broad  dorsal 
longitudinal  keel.  EB.  1840,  p.  18. 
Fossil.  Shores  of  the  Rhine,  in  volcanic 
schists.     1-216". 

N.  diaphana  (E.).  —  Large,  smooth, 
diaphanous,  elongated,  lanceolate,  with 
obtuse  apices ;  the  umbilicus  intercepting 
the  double  median  line.  EB.  1845, 
p.  78.  Guiana.  1-192".  Habit  of  Stau- 
7'oneis  phoenicenfc'ro}i. 

N.  Schombto'f/kormn  (E.).  —  Large, 
elongated,  lanceolate,  with  obtuse  apices, 
and  the  habit  of  iV.  diapJuoia,  but  with 
three  longitudinal  median  lines.  EB. 
1845,  p.  79.     Guiana.     1-180" 

N.  latiuscida  (K.). 
oblong  or  elliptic-lanceolate,  with  rather 
obtuse  apices ;  strise  shorter  opposite  the 
central  nodule,  10  to  12  in  1-1200". 
KB.  p.  93,  pi.  5.  f.  A:0.  =  N.i)atula.  SB. 
i.  p.  49,  pi.  16.  f.  139.  Europe,  Ireland. 
Twice  as  long  as  broad ;  front  view 
broadlv  linear,  with  truncate  ends. 


Bather    large, 


N.  ScJiomhurgMi  (E.,  K.).  —  Large, 
lanceolate,  equal,  three  times  as  long 
as  broad,  with  subacute  apices,  and  25 
stride  in  1-1152".  KA.  p.  71.  =  Pin- 
nularia Schornhurgkii,  EB.  1845,  p.  80. 
Guiana.  Is  smaller  and  more  obtuse 
than  N.  cequaUs. 

N.  palpehralis  (Breb.).  — Broadly  lan- 
ceolate, with  subacute  apices,  and  27 
radiant  strise  in  -001",  which  do  not 
reach  the  median  line.  SD.  i.  p.  50, 
pi.  31.  f.  273.  Marine.  France,  Britain. 
Striae  short,  leaving  a  lanceolate  median 
blank  space. 

N.  angulosa  (Greg.). — Broadly  lanceo- 
late or  oblong,  with  subacute  apices; 
striae  conspicuous,  short,  forming  a  nar- 
row marginal  band,  shorter  near  the 
middle,  and  leaving  a  smooth,  rhomboid 
median  space.  TM.  iv.  p.  42,  pi.  5.  f.  8. 
Marine.  Britain.  N.  angidosa  is  larger 
than  N.  jmlpebralis,  and  the  angidar  me- 
dian space  is  a  good  and  permanent  mark 
of  distinction;  nodule  definite. 

N.  radiosa  (K.).  —  SmaU,  slender- 
lanceolate,  with  subacute  apices,  and 
fi'om  15  to  18  distinct,  radiant  striae  in 
1-1200".  KB.  p.  91,  pi.  4  f.  23.  =  Pin- 
nularia radiosa,  SD.  i.  p.  50,  pi.  18.  f.  173. 
Gei-many,  Britain.  With  stronger  striae 
than  N.  gracilis. 

N.  vulpina  (K.). — Rather  tiu'gid,  lan- 
ceolate, with  acute  apices;  front  view 
broadly  linear,  with  tnmcate  ends  and 
punctate  margins ;  striae  obscure.  KB. 
p.  92,  pi.  3.  f.  43.  Germany.  Inter- 
mediate between  N.  gracilis  and  N.  cus- 
pidata. 

N.  cuspidata  (K.).  —  Broadly  lanceo- 
late, wdth  acute  apices,  a  very  minute, 
orbicular  central  nodule,  and  close,  very- 
fine  transverse  striae.  KB.  p.  94,  pi.  3. 
f.  24,  37 ;  SD.  i.  p.  47,  pi.  16.  f.  131.  =  Na- 
viculafulva,  EM.  many  figm-es.  Common. 
Em-ope,  Asia,  Africa,  x\merica.  (xn.  5.) 
Front  view  narrow-linear.  1-1150"  to 
1-180".  The  lateral  view  is  broader  and 
more  rhomboid  than  in  N.  gracilis. 

N.  Cafitonensis  (E.). — Broadly  oblong- 
lanceolate,  with  acute,  slightly  produced 
apices ;  striae  wanting  or  indistinct.  EB. 
1847,  p.  484.  Canton.  1-480".  It  difters 
from  N.  cusjridata  in  its  shorter  and  acute 
apices. 

N.  amphisphenia  (E.).  —  Lanceolate, 
navicidar,  gradually  attenuated  into  the 
apices,  with  an  oblong  median  nodule; 
striae  wanting  or  obsciu'e.  Exl.  p.  129; 
EM.  pi.  9. 1.  f.  16.  America,  Asia,  Africa, 
Europe.  Distinguished  from  N.  cuspi- 
data by  its  oblong  nodide. 

N.  phyllepta  (K.).  —  Minute,  slender^ 


800 


SYSTEMATIC  HISTOEY  OF  THE  IFFUSOSIA. 


smooth,  naiTow-lanceolate,  with  acute 
apices;  front  view  strictly  linear,  wath 
truncate  ends.  KB.  p.  94,  pi.  30.  £  56. 
Marine.     Eiu'ope. 

IS\  Meleagris  (K.). — Somewhat  tm'gid, 
lanceolate-acuminate,  with  an  elegantly 
punctate  margin.  KB,  p.  92,  pi.  SO.  f.  37. 
Marine.  Em-ope.  Front  view  broadly 
linear. 

N.  (jracilis  (K).  —  Small,  elongated, 
slender-lanceolate,  vnt\i  subacute  ends; 
striae  very  fine,  radiant,  22  in  -001", 
reaching  \he  median  line.  E.  Infus. 
p.  170;  EM.  many  figures.  Em'ope,  Asia, 
Afi-ica,  America,  Lough  Moiu'ne  deposit. 
1-1500"  to  1-5G0". 

N.  oxyptera  (K.). — Elongated,  slender, 
narrow-lanceolate,  with  acute  apices,  and 
fine,  slightly  radiant,  transverse  striae. 
KSA.  p.  69.  =^Piiuuilaria  (unphioxys,  EM. 
manyfigm-es ;  P.  acuta,  SB.  i,  p.  56,  pi.  18. 
f.  171.  Em'ope,  Asia,  Australia,  Africa, 
America. 

N.  Kefvingensis  (E.). — Small,  striated, 
lanceolate,  navicular;  striie  converging 
at  the  centre,  17  in  1200".  EB.  1840, 
p.  20.  =  Pinmilaria  Kefvingmsis,  EM. 
pi.  10.  2.  f.  4,  5.  Fossil.  Bohemia, 
Asia. 

N.  peregrina  (E,,  K.). — Striated,  nar- 
row-lanceolate, gradually  tapering  to  the 
subacute  apices ;  pinnules  oblique,  reach- 
ing the  median  line,  13  in  -001".  KB. 
p.  97,  pL  28.  f.  o2.  =  Pinnidaria  jJeregriua, 
EA.  p.  133,  several  figm^es ;  SI),  i.  p.  56, 
pi.  18.  f.  170.  Marine.  Em'ope,  Asia, 
Africa,  America. 

N.  leptostigma  (E.).  —  Striated,  lan- 
ceolate, vv-ith  subacute,  slightly  produced 
apices;  the  ti-ansverse  dotted  striae  in- 
conspicuous. EB.  1845.  =  Finmdaria 
leptostigma,  EM.  pi.  33.  12.  f.  25.  FossH. 
United  States.  Twice  as  long  as  broad. 
1-4:32". 

N.  Ehrenhergii(K.). — Lanceolate,  with 
somewhat  acute  apices,  and  fine,  radi- 
ating stiia?.  KB.  p.  92,  pi.  3.  f.  38.  = 
Navicula  lanceolata,  E.  Inf.  pi.  13.  f.  21. 
Em'ope. 

N.  ticglecta  (K.). — Turgid,  lanceolate, 
with  subacute  apices,  margins  longitu- 
dinallv  costate  and  transverselv  striated. 
KB.  p.  92,  pi.  28.  f.  U.=PinnuIana  lan- 
ceolata, EA.  pi.  3.  1.  f.  6.  Europe,  Ame- 
rica. Front  view  oblong,  with  incras- 
sated  middle  and  truncate  ends.  1-1150" 
to  1-280";  strict  13  in  1-1200". 

IvI.  Scmproma  (Perty).  —  Minute, 
acutely  lanceolate ;  striae  not  reaching 
the  median  line ;  front  view  linear, 
slightly  narrowed  towards  the  ends. 
Perty,  Microsc.  Org.  p.  204,  pi.  17.  f.  8. 


Alps.  Belongs  to  the  smaller  species, 
and  is  very  like  N.  exilis. 

N.  directa  (S.).  —  Slender,  naiTow- 
lanceolate,  acute ;  costae  fine,  parallel, 
reaching  the  median  line,  20  in  -00 1". 
=  Pinwdaria  directa,  SD.  i.  p.  56,  pi.  18. 
f.  172.  Marine.  Sussex.  Front  view 
narrow-linear. 

N.  pidchra  (Greg.). — Broadly  lanceo- 
late or  somewhat  rhomboid ;  striae  radi- 
ant, strongly  moniliform,  nearly  reaching 
the  median  line,  shorter  opposite  the 
slightly  dilated  indefinite  nodides.  TM. 
iv.  p.  42,  pi.  5.  f.  7.  Marine.  Scotland. 
Rapidly  tapering  to  the  obtuse  apices. 

N.  longa  (Greg.). —  INIuch  elongated, 
lanceolate  or  slightly  rhomboid,  acute ; 
costae  conspicuous,  about  12  in  '001", 
nearly  reaching  the  median  line,  some- 
what shorter  and  radiant  opposite  the 
central  nodule.  =Pi}i?iulana  longa,  Greg. 
TM.  iv.  p.  47,  pi.  5.  f.  18.  Scotland.  The 
only  known  form  to  which  it  has  any 
resemblance  is  N.  directa,  but  the  latter 
form  is  not  rhombic,  and  the  striae  are 
much  more  numerous  and  parallel. 

N.  acutiuscula  (Greg.).  —  Elongated, 
slender,  linear-lanceolate,  acute;  costao 
distinct,  about  30  in  -001",  reaching  the 
median  line,  central  ones  radiant  and 
more  conspicuous.  =  Pw/«//a/7«  acutias- 
cula,  TM.  iv.  p.  48,  pi.  5.  f.  21.     Scotland. 

N.  costata  (K.).  —  Oblong-lanceolate, 
Vk-ith  obtuse  apices,  and  longitudinal 
pmictated  lines;  median  nodule  large, 
terminal  ones  minute.  KB.  p.  93,  pi.  3. 
f.  56.  Fossil.  Santa  Fiore.  Front 
^dew  oblong,  with  broadly  rounded 
apices. 

N.  Norvegica  (E.,  K.). — Broadly  ob- 
long, with  acute  apices,  a  narrow  striated 
border,  and  a  smooth  median  space ;  striae 
30  in  1-1200".  KA.  p.  79.  =  Pin?mlaria 
Norvegica,  E.  Marine.  Europe.  Front 
view  narrow-linear,  truncate.     1-360''. 

N.  Lihyca  (E.).  —  Small,  striated, 
acutely  oblong-lanceolate,  with  14  striae 
in  1-1200" ;  front  view  quadrangidar, 
T\dth  truncate  ends.  EB.  1840,  p.  20. 
Sinai.  1-550".  It  has  the  habit  of  N. 
fidva,  but  is  wider,  and  not  rostrate. 

N.  Piqmla  (K.).  —  Minute,  smooth, 
oblong-lanceolate,  with  slight  produced 
apices.    KB.  p.  93,  pi.  30.  £  40.    Europe, 

N.  cdpina  (S.). — Large,  oblong-lan- 
ceolate, with  obtuse  ends,  and  7  to  9 
stout,  distant,  radiant  costae  in  '001", 
which  do  not  reach  the  median  line.= 
Pimndaria  cdpina,  SD.  i.  p,  55,  pi.  18. 
£  168,  France,  Scotland.  Front  view 
broadly  linear,  with  truncate  ends;  costae 
shorter  near  the  central  nodule. 


OF  THE  NAVICrLE^E. 


907 


N.  distiuts  (S.).  —  Lanceolate,  with 
subacute  apices ;  costas  radiant,  distant, 
10  in  -001",  not  reaching  the  median 
line.  =  Pi)im(laria  distans,  SD.  i.  p.  56, 
pi.  18.  f.  1G9.  Marine.  Conmion,  espe- 
cially from  deep  dredgings.  Costi© 
shorter  opposite  the  central  nodide. 

N.  elegans  (S.J.  —  Broadly  or  elliptic 
lanceolate,  with  slightly  acuminated 
ends;  strise  distinct,  24  in  -001",  waved, 
radiate,  nearly  reaching  the  median  line, 
sliorter  opposite  the  central  nodule. 
SD.  i.  p.  49,  pi.  16.  f.  137.  Marine. 
England. 

N.  jjermctf/na  (Bai.).  —  Large,  turgid- 
lanceolate,  with  obtuse  apices,  a  mar- 
ginal baud  of  pimctated  striae,  and  a 
broad,  lanceolate,  longitudinal  median 
blank  space  ;  nodido  indefinite.  =  P/«/»^- 
fariapermarpm,  BMO.  p.  40,  pi.  2.  f.  28  & 
'38.     Luited  States. 

II.    Valves  linear  or  ohlong,  neither 
rostrate  nor  constricted. 

t  Ends  scarcely  cuneate. 

N.  BaciUum  (E.j. — Linear,  with  trun- 
cate, romided  ends ;  strias  indistinct,  54 
in  -001".  EM.  several  figures.  =  iV".  hacil- 
laris,  Greg.  ML  iv.  pi.  1.  f.  24.  Ehren- 
berg  gives  about  50  habitats  in  Em-ope, 
Asia,  Australia,  Africa,  and  America. 

N.  borealis  (E.,  K.). — Small,  stiiated, 
linear,  with  slightly  attenuated,  rounded 
apices ;  strine  stout,  rather  distant,  not 
reaching  the  median  line,  13  in  -001". 
KB.  p.  96,  pi.  28.  f.  68-72.  =  Pinmdaria 
hurealis,  EM.  numerous  figures;  Pinnu- 
laria  latestriata,  Greg.  MJ.  ii.  pi.  4.  f.  13. 
(VII.  74.)  A  very  common  and  widely 
diliused  species.  Ehrenberg  gives  about 
200  habitats  for  it.  (3  longer  and  more 
dilated  at  the  middle,  =  Pinmdaria 
Caraccana,  E.  Under  moss  on  trees. 
The  front  "view  of  this  species  is  linear, 
with  truncated  ends  and  striated  mar- 
gins, and  resembles  that  of  detached 
frustides  of  DeuticrJa  and  Odontidium. 

N.  Chilensis  (E.,  K.). — Large,  linear, 
with  broadly  rounded  apices,  and  11  or 
12  stout  costie  in  1-1200".  KA.  p.  79.  = 
Pinmdaria  CMensis,  EM.  pi.  34.  11.  f.  3. 
Australia,  Asia,  Africa,  America,  (xii. 
33.)  Costre  parallel,  equal.  Approaches 
to  N.  riridis,  but  is  shorter  and  broader. 

N.  rcctamjidata  (Greg.). — Linear,  with 
truncate  rounded  ends ;  costae  rather  di- 
stant, 22  in  -001",  nearly  reaching  the 
median  line,  except  opposite  the  dilated 
indefinite  nodide,  and  there  shorter  and 
diverging.  GDC.  p.  7,  pi.  1.  f.  7.  Marine. 
Scotland. 


N.  Iridis  (E.).  —  Large,  elongated, 
linear-oblong,  tapering  into  the  obtuse 
apices,  finely  striated  both  longitudinally 
and  transversely,  iridescent.  EA.  p.  130, 
pi.  4.  1.  f.  2.     New  York. 

N.  oblonga  (K,). — Elongated,  slender, 
oblong  or  linear- oblong,  with  rounded 
apices ;  costae  stout,  connivent  at  the 
centre.  KB.  p.  97,  pi.  4.  f.  21.  =Pinmi- 
laria  iJohjjitera,  EA.  p.  133 ;  P.  macHenta, 
E.  Common.  We  follow  Kiitzing  and 
Smith  in  referring  P.  macilcnta,  E.,  to 
this  species ;  Ehrenberg's  figures,  how- 
ever, differ  from  theirs  in  being  more 
linear,  with  less  tapering  apices.  1-140". 

N.  Orecjonica  (E,,  K.).  —  Elongated, 
bacillar,  uniformly  and  gradually  de- 
creasing towards  the  rounded  apices; 
pinnules  stout,  23  in  1-11.52".  KA. 
p.  7\.=Pinnidaria  Oregonica,  EB.  1845, 
p.  79.  Fossil.  Oregon.  1-228".  It 
approaches  to  N.  Digitus,  but  is  more 
slender. 

N.  truncata  (K.). — Minute,  smooth, 
linear,  with  tnmcato-rounded  ends,  and 
an  inner  marginal  border  twice  con- 
stricted ;  front  view  broadly  linear, 
truncate.  KB.  p.  96,  pi.  3.  f.  34.  Eu- 
rope. 

N.  Liher  (S.). — Linear-oblong,  with 
rounded  apices,  and  48  delicate  striae  in 
•001" ;  colour  of  drv  valve  purplish. 
SD.  i.  p.  48,  pi.  16.*^  f.  133.  Marine. 
Sussex. 

N.  Stylm  (E.).  —  Elongated,  narrow- 
linear,  with  rounded  ends,  and  having 
longitudinal  dotted  lines  on  each  side. 
EM.  pi.  15  A.  f.  36.  Asia ;  Lough  Momiie 
deposit. 

N.  Ergadensis  (Greg.). — Rather  small, 
narrowly  linear-oblong,  vnth.  roimded 
ends ;  costae  distinct,  25  in  -001",  nearly 
reaching  the  median  line,  shorter  and 
radiant  opposite  the  roundish,  smooth 
umbilical  ^^^cq.-=  Pinmdaria  JErqadensiSf 
TM^  iv.  p.  48,  pi.  5.  f.  22.     Scotland. 

N.  styliformis  =■  Pinmdaria  styliformis, 
EM.  pi.  38  A.  17.  f.  6.  Australia,  Africa, 
America.  Ehrenberg's  figure  represents 
a  portion  of  an  elongated,  naiTow,  strictly 
linear  valve,  with  rhomboid  ends,  and  fine, 
parallel  striae  whicli  reach  the  median 
line. 

N.  Dactglus  (E.,  K.). — Large,  elon- 
gated, linear-oblong,  passing  by  a  very 
gentle  curve  into  the  slightly  narrower, 
broadlv  roimded  apices ;  pinnules  14  in 
1-1200".  KB.  p.  98,  pi.  28.  f.  59.= 
Pinmdaria  Dactglus,  EA.  p.  132,  pi.  4.  1. 
f.    3.     Europe,   Asia,   Africa,  iimerica. 


Lough  Mourne  deposit. 
N.  viridis  (Nitzsch,  K.).- 


-Elongated, 


908 


SYSTElVLiTIC  HISTOEY  OF  THE  INFUSORIA. 


slender,  linear-oblong  or  linear  lanceo- 
late, with  obtuse  apices ;  12  to  14  radiant 
costte  in  1-1200",  shorter  opposite  the 
central  nodule.  KB.  p.  97,  pi.  4.  f.  18.  = 
Pinmdaria  viricUs,  E.,  in  part  ?  ;  Nadcula 
viricMa,  E.  (ix.  133-136.)  Common. 
1-3000"  to  1-280". 

N.  hemiptcra  (K.). — Narrow,  linear- 
oblong-,  with  obtuse,  conic  apices,  and 
14  or  15  radiant  costie  in  1-1200",  which 
do  not  reach  the  median  line.  KB. 
p.  97,  pi.  30.  f.  11.  =  Pinnularia  hemiptera, 
SD.  ii.  p.  95.  America,  Europe.  Front 
view  linear,  with  rounded  angles.  Often 
overlooked  from  its  resemblance  to  A^. 
viricUs,  fi'om  which  it  is  distinguished  by 
its  finer  stiifo  and  narrower  valve. 

N.  cequinoctiaUs  (Mont.).  —  Rather 
large,  linear-oblong,  with  rounded  apices, 
and  4  stout,  radiant  pinnules  in  1-2600". 
Montague,  Annales  des  Sciences  Nat. 
1850,  p.  309.  Guiana.  1-260"  to  1-150". 
In  form  it  resembles  N.  Dactijlus,  but 
differs  in  its  size  and  much  larger  striae. 
In  the  latter  respect  it  approaches  to  N. 
ixichyptera,  but  has  not  the  median  infla- 
tion of  that  species. 

N.  pleuropliora  (K.). — Large,  stout, 
oblong,  or  linear-oblong,  with  broadly 
rounded  ends,  and  6  stout  costse  in 
1-1200".  KA.  p.  79.  =Pimmlaria  costata, 
EM.  pi.  4. 2.  f.  5 ;  Pimmlaria  megaloptera, 
EM.  pi.  3.  1.  f.  4.     America,  Asia. 

N.  Suecica  (E.). — Oblong-elliptic,  with 
broadly  roimded  ends,  short,  stout,  rather 
distant  marginal  costce,  and  large  central 
blank  space.  E  Inf.  p.  189,  t.  21.  f.  18.  = 
Pinnularia  Suecica,  EM.  Fossil.  Sweden. 
N.  lota  (Breb.). —  Large,  linear-ob- 
long, with  roimded  apices,  and  8  stout 
costre  in  -001",  which  do  not  reach  the 
median  line,  and  are  shorter  and  some- 
what connivent  opposite  the  central 
nodule.  KA.  p.  79.  =  Pinnularia  lata, 
SD.  i.  p.  55,  pi.  18.  f.  167.  France,  Bri- 
tain. Front  view  very  broad  linear,  with 
rounded  angles,  truncate  ends,  and 
striated  margins;  the  central  nodules 
large.  This  species  approaches  closely 
in  character  to  iV.  Suecica. 

N.  Digitus  =  Pinmdaria  Digitus,  EM. 
pi.  33.  8.  f.  15  ;  pi.  38  a.  3  b.  f.  1.  Ame- 
rica, Java.  This  species  is  figm^ed  as 
large,  linear-oblong,  with  broadly 
rounded  ends,  and  stout,  parallel  costae 
which  do  not  reach  the  median  line. 

N.  Dux  =i  Pinmdaria  Dux,  EM.  pi.  8.  2. 
f.  5.  Fossil.  Hungary.  Ehreuberg  repre- 
sents it  as  large,  elliptic-oblong,  with 
rounded  ends  and  divergent  costae,  which 
do  not  reach  the  median  line,  and  are 
shorter  opposite  the  central  nodide. 


N.  ostrearia  (K.).  —  Small,  elliptic- 
oblong,  with  rounded  ends,  large  central 
nodule,  and  close,  fine  striae.  KA.  p.  77. 
Marine.     France. 

N.  retusa  (Breb.). — Striated,  nan'ow- 
linear,  with  roimded  ends ;  front  view 
broad,  quadrate,  with  rounded  angles, 
ti-uncate  ends,  and  concave  and  striated 
lateral  margins.  Breb  DC.  p.  16,  pi.  1. 
f.  6.  Marine.  Europe.  The  frustules 
are  much  compressed ;  and  consequently 
the  front  view  is  so  much  broader  than 
the  lateral  surfaces,  that  it  is  difiicult  to 
obtain  a  good  sight  of  the  latter.  N. 
retusa,  N.  apiculata,  and  a  few  allied  spe- 
cies probably  ought,  as  suggested  by  M. 
de  Brebisson,  to  form  a  separate  group,  if 
not  a  distinct  geniLS,  distinguished  by 
the  great  comparative  breadth  of  its 
front  view,  with  its  striated  and  sinu- 
ated  or  constricted  lateral  margins. 

N.  scita  (S.). — Nitescent,  linear-ob- 
long, with  attenuated,  obtuse  ends;  striae 
verv  faint,  45  in  -001"  ;  nodule  small. 
ANH.  1857,  xix.  p.  8,  pi.  2.  f.4.  Pyrenees. 

N.  parvula  (Greo-.). —  Small,  narrow 
linear  "lanceolate,  with  obtuse  ends  and 
distinct  costa3,  which  do  not  reach  tlie 
median  \me.  =  Pinnularia  parva,  MJ.  ii. 
p.  98,  pi.  4.  f.  11.     MuU. 

2t  Valves  linear  or  oblong,  with 
cimeate  ends. 

N.  ampkigomphus  (E.).  —  Large, 
broadly  linear,  with  sharply  cuneate  ends, 
with  or  without  obscm-e  longitudinal 
lines ;  striae  obsolete  or  distinct.  EA. 
p.  129,  pi.  3.  1.  f.  8 ;  EM.  many  figm-es. 
America,  iVsia,  Europe.  Lough  Moume 
deposit.  j3,  striae  distinct.  =  Pinnularia 
ampUigmnphus,  EM.  pi.  14.  f.  11. 
Cayenne,  France. 

N.  dilatata  (E.). — Large,  oblong  or 
broadly  linear,  with  obtuse,  cuneate  ends, 
and  furnished  with  longitudinal  lines 
near  the  margins.  EM.  many  figiu*es. 
Europe,  Lough  Mourne. 

N.  disjyhenia  (E.,  K.).  —  Linear,  elon- 
gated, with  shai-ply  cuneate  ends,  finely 
striated  near  the  margins.  KB.  p.  93, 
pi.  28.  f.  54.  =  Pinnularia  clisjjhenia,  EA. 
p.  132.  America,  Australia.  Approaches 
to  N.  amjyJiigomphus. 

N.  acuta  (K.). — Narrow-linear,  smooth, 
with  acute,  shortly  cimeate  apices.  KB. 
p.  93,  pi.  3.  f.  49.  Island  of  Wangerooge, 
Australia. 

N.  subaada= Pinnularia  suhacuta,'FM. 
pi.  35  A.  6.  f.  12.  Perth,  Australia. 
Ehrenberg's  figure  represents  this  species 
as  linear,  with  cimeate  apices,  fine,  close, 


OF  THE  NAVICULE^. 


909 


parallel  stiia3,  wliicli  reach  the  median 
line,  and  a  small  central  nodule. 

N.  acuminata  (S.).  —  Linear,  with 
acutely  cuneate  ends  and  parallel  costae^ 
which  do  not  reach  the  median  line.  = 
Pinmdaria  acuminata,  SD.  i.  p.  55,  pi.  18. 
f.  1G4.     Prenmay  peat. 

N.  minor  (Greg.).  —  Minute  ;  lateral 
view  linear,  with  acutely  cuneate  ends ; 
strias  fine,  nearly  parallel,  not  reaching 
the  median  line,\36  to  40  in  -001".  GDC, 
p.  5,  pi.  1.  f.  1.     Scotland. 

N.  crassa  (Greg.). — Linear-  or  elliptic- 
oblong,  with  obtusely  cuneate  ends ; 
strice  tine,  but  distinct,  moniliform,  radi- 
ant, nearly  reaching  the  median  line,  but 
leaving  an  orbicular  blank  space  round 
the  central  nodule.  MJ.  iii.  p.  41,  pi.  4. 
f.  18.  Scotland.  Is  of  a  brown  colom- 
in  balsam. 

N.  Utricuhis  (E.,  K.).  —  Striated, 
linear-oblong  ;  ends  attenuated,  with  a 
slight  marginal  curvature,  into  the  obtuse 
apices.  KB.  p.  9S.  =  Pinnularia  Utri- 
culus,  EA.  p.  134.  Mexico.  Alnn  to 
iV^.  disphenia. 

N.  trigonocephala  (E.).  —  Striated, 
linear,  with  the  ends  dilated  into  large 
cuneate  heads.  =  Pinnularia  trigonoce- 
phala, EM.  pi.  34.  8.  f.  11.^  Japan.  Very 
unlike  any  other  species  in  having  the 
cuneate  heads  much  dilated  and  broader 
than  the  intermediate  portion. 

N.  microstoma  (K.). — Large,  turgid, 
elongated  oblong,  vdtii  obtusely  cimeate 
ends,  longitudinal  lines,  and  a  veiy  mi- 
nute oblong  median  nodule ;  striae  nume- 
rous, obscure.  KA.  p.  71.  =iV.  lata,  KB. 
p.  92,  pi.  3.  f.  51;  N.Jirma,^  SD.  p.  48, 
pi.  16.  £.  138.  Europe.  Front  view  broadly 
linear,  with  truncate  ends,  roimded  an- 
gles, and  broad  lateral  borders,  tm'gid  at 
the  middle.  Perhaps  Professor  Smith 
was  right  in  imiting  this  to  N.Jirma. 

'N.Jirma  (K.). — Large,  tm^gid,  oblong- 
lanceolate,  with  obtuse,  cuneate  ends, 
thick  borders,  and  largo  median  nodule  ; 
striae  wanting  or  obscure.  KB.  p.  92, 
pi.  21.  f.  10.     Fossil.     Santa  Fiore. 

N.  maxima  (Greg.). — Large,  striated, 
linear,  with  longitudinal  lines,  and  ob- 
tuse, cuneate  or  conic  ends ;  striae  fine, 
parallel,  nearly  reaching  the  median  line, 
shorter  opposite  the  central  nodule, 
about  52  in  -001".  GDC.  p.  15,  pi.  1. 
f.  18.  Marine.  Britain.  (vii.  75.) 
Generally  elongated ;  nodule  definite, 
surrounded  by  a  smooth  space.  Front 
view  linear,  naiTowest  at  the  middle, 
with  striated  margins.  Differs  from  N. 
jirma  in  its  paler  colom',  finer  striae,  and 
more  obtuse  apices,  Greg. 


^.formosa  (Greg.).— Large,  striated, 
linear  or  linear-oblong,  with  longitudinal 
lines,  obtuse,  cuneate  or  conic  ends ; 
striae  distinct,  slightly  inclined,  not 
reaching  the  median  line,  shorter  oppo- 
site the  large  central  nodule,  about  35 
in  -001".  TM.  iv.  p.  42,  pi.  5.  f.  6. 
Marine.  Scotland.  Agrees  in  form  with 
H.  maxima,  but  is  distinguished  by  its 
more  conspicuous  and  slightly  inclined 
striae  which  do  not  reach  the  median 
line,  leaving  a  longitudinal  median  blank 
band. 

N.  Kerguelensis  (R.).  —  Oblong,  with 
obtusely  cuneate  ends  ;  costae  stout, 
radiant ;  nodule  indefinite.  =  Pinnularia 
Kerguelensis,YM.^l.  35  a. 2.  f.  15.  Afiica. 

I.    Valves  elliptic,  with  rounded  ends. 

N.  cocconeoides  (Rdh.).  —  Small,  ellip- 
tic, with  broadly  romided  ends,  and  11 
to  13  parallel  and  distinct,  but  faint 
strict  in  1-1200",  which  reach  the  median 
line.  =  Pinnularia  cocconeoides,  Kab  D. 
p.  43,  pi.  6.  f  18.     Stockholm. 

^  N.  scutelloides  (S.).  —  Small,  subor- 
bicular,  with  18  monilifomi,  radiant 
striae  in  -001",  nearly  reaching  the 
median  line.  SD.  ii.  p.  91 ;  Greg.  MJ.  iv. 
pi.  1.  f.  15.     Britain. 

_N.  pectincdis  (Breb.). — Linear-elliptic, 
Tvith  roimded  ends,  and  22  striae  in  -001". 
SD.  ii.  J).  92.  Marine.  France,  Britain. 
Front  view  with  truncate  ends. 

N.  Algeriensis  (jNIont.). — Elliptic-ob- 
long, with  10  striae  on  each  margin. 
M.  Fl.  d' Alger,  p.  190.   Marine.    Algiers. 

N.  Cluthensis  (Greg.).— Elliptic,  with 
broadly  rounded  ends ;  striae  conspicu- 
ous, moniliform,  reaching  the  median 
line,  about  20  in  -001";  median  line 
broadest  at  the  central  nodule,  slightly 
attenuated  towards  the  ends.  GDC. 
p.  6,  pi.  1.  f.  2.     Scotland,     (vn.  73.) 

N.  oralis  (Nag.).  —  Finely  striated, 
oval  elliptic  j  front  view  broadly  linear. 
1-720"  to  1-600".  KA.  p.  890.  Switzer- 
land. 

N.  oblongella  (Nag.).  —  Smooth,  ob- 
long-oval ;  front  view  broadly  linear. 
1-720  '  to  1-430".  KA.  p.  890.  Switzer- 
land. 

^  ^.fossilis,  EM.  pi.  10. 1.  f.  6.  Bohemia. 
Ehrenberg's  figure  shows  this  species 
elliptic,  slightly  rhomboid,  with  rounded 
ends ;  the  median  sutm-e  of  three  lines, 
interrupted  by  the  indefinite  central 
nodule. 

N.  nana  (Greg.  MS.). — Minute,  oval, 
obtuse.;  costae  radiant,  nearly  reaching 
the  median  line;   umbilical  space  not 


910 


SYSTEMATIC  HTSTOPvY  OF  THE  I'N'FUSORIA. 


dilated.  =  Pinmdaria  inj(im(Ba,  EM. 
pi.  10.  1.  f.  9 ;  MJ.  iv."  pi.  1.  f.  8. 
Europe. 

N.  lepida  (Grreg.). — Minute,  hyaliue, 
oval,  or  oblong,  with  obtuse  ends ;  striae 
indistinct  from  tlieir  transparency, 
slightly  radiant.  MJ.  iv.  p.  7,  pi.  1. 
f.  25.     Scotland. 

N.  oceanica.  —  Elliptic-oblong,  twice 
as  long  as  broad,  with  subacute  apices, 
small,  round,  cleaiiy-dciined  umbilicus, 
and  double  median  line;  margin  deli- 
cately but  widely  striated ;  pinnules  20 
in  1-1200".     Southern  Ocean.     1-570". 

K.  Median  line  Jlexuose. 

N.  tumicla  (Breb.)-  —  Large,  tumid, 
striated,  twisted,  oblong,  with  obtuse 
apices,  a  liexuose  median  line,  and  close, 
fine  strife,  which  reach  the  median  line. 
KA.  p.  77.  =  iV.  Jennerii,  SD.  i.  p.  49, 
pi.  16.  f.  134.  Marine.  France,  Britain. 
(VII.  55.)  Front  view  broad  linear  ob- 
long, with  rounded  angles;  frustules 
t\vasted,  so  that  the  hyaline  central  por- 
tion appears  ilexuose. 

N.  coni-exa  (S.). — Large,  tumid,  stri- 
ated, twisted,  linear  oblong,  with  conic 
apices,  a  ilexuose  median  line,  and  21 
strife  in  -001",  which  do  not  quite  reach 
the  median  line.  SD.  i.  p.  49,  pi.  18. 
f.  136.  Marine.  England.  Front  view 
broadly  linear-oblong,  with  rounded 
angles,  and  a  narrow,  flexuose,  longi- 
tudinal median  band. 

N.  Westii  (S.). — Broadly  lanceolate, 
with  subacute  apices,  and  38  delicate 
strise  in  -001",  which  nearly  reach  the 
slightly  flexuose  median  line.  SD.  i. 
p.  49,  pi.  16.  f.  135.  Marine.  England. 
Colour  of  dry  valve  dark  purple;  front 
view  linear,  ^vith  rounded  angles,  and  a 
narrow,  slightly  ilexuose  median  band. 

N.  ?  camjjylogramma  (E.).  —  Small, 
o\ate,  obtuse,  smooth,  with  a  flexuose, 
sigmoid  median  line,  and  orbicular  cen- 
tral nodide.  EB.  1853,  p.  36.  Bavaria, 
Rhine.  Probably  identical  with  Aehnan- 
thidiumjlexellum,  since  Ehrenberg  states 
that  he  has  seen  it,  together  with  Aeh- 
nanthes  ?  Bavarica,  distributed  imder  the 
name  of  CymheUaJlexella. 

N.  tortuosa  (E.). — Smooth,  crystalline, 
rather  turgid,  and  somewhat  tortuous, 
so  that  one  end  has  a  more  obtuse  apex. 
EB.  1843,  p.  271.     1-288". 

N.  dissimilis  (S.). — Frustules  oblique  ; 
elliptic ;  median  line  somewhat  diagonal 
from  the  obliquity  of  the  frustule,  re- 
curved at  extremities;  striae  obscure. 
ANH.  1857,  xix.  p.  8,  pi.  2.  f.  6.  Pyrenees. 


L.  Frustules  luncdehj  curved  in  the 
front  vieiv. 

N.  c/emiflexa  (K.).— Parasitic,  smooth, 
narrow-lanceolate,  obtuse;  front  view 
linear,  with  truncate  ends,  Innately 
em-ved.  KB.  p.  101,  pi.  21.  f.  6.  Marine. 
Peru. 

M.  Frustules  lunatehj  curved  in  the 
lateral  view. 

N.  Neapolitana  (Bab.).  —  Luuately 
curved,  linear,  with  truncate  ends,  and 
transverse  striae.  =  Falcatella  Neajwli- 
tana,  Rab  D.  p.  46,  pi.  5.  f.  3.     Italy. 

N.  lunata  (K.). —  Smooth,  small.  In- 
nately cmTed,  narrow-linear,  with 
slightly  romided  ends ;  front  view 
linear,  truncate.  KB.  p.  101,  pi.  4. 
f.  1.  4,.  =  Falcatella  lunata,  Rab  D.  p.  46. 
Italy. 

]:^.Roma7ia  (Rab.). — Smooth,  attached 
by  a  gelatinous  base;  Innately  curved, 
linear,  wdth  truncate  ends ;  front  view 
linear  lanceolate,  truncate,  =  Falcatella 
Romana,  Rab  D.  p.  46,  pi.  5.  f.  1.    Italy. 

Doubtful  or  insirfficienthj  described 
Species. 

N.  varians  (Greg.). — Form  and  size 
variable ;  strife  oblique,  1 4  to  18  in 
•001",  nearly  reaching  the  median  line, 
more  conspicuous  opposite  the  central 
nodule,  and  highly  radiant.  TM.  iii. 
p.  12,  pi.  2.  Britain.  In  this  species 
Professor  Gregor}'  disregarded  form  and 
size,  considering  the  number  and  dispo- 
sition of  the  strise  as  the  essential  cha- 
racters. 

N.  mutabilis  (Greg.). — ^Form  and  size 
variable ;  strife  as  in  N.  varians,  but 
finer,  and  from  24  to  26  in  -001".  TM. 
iii.  p.  \L=  Pinmdaria  exigua,  MJ.  ii. 
pi.  4.  f.  14.  Britain.  We  concur  in 
opinion  with  the  late  Professor  Smith, 
that  these  species  are  too  vaguely  de- 
fined, and  that  probably  they  are  con- 
stituted of  forms  belonging  to  various 
other  species. 

N.  mimdissima  (Rab.). — Exceedingly 
minute,  but  with  distinct  median  nodule. 
Rab  D.  p.  39,  pi.  6.  f.  80.     Persia. 

N.  meqalodon  =  Pinnularia  mecjalodon, 
EM.  pi.'  33.  14.  f.  21.  America.  The 
central  portion  of  a  large,  oblong  species, 
with  stout,  distant,  parallel  costfe,  which 
do  not  reach  the  median  line. 

N.  ompludia  (E.). — Large,  iridescent, 
Math  very  fine,  granulated,  decussating 
lines;  umbilicus  orbicular,  solid,  hyaline, 
divided  by  the  straight  median  line. 
Fossil.     Fragments  in  Bermuda  deposit. 


OF  THE  NATICULE.ig. 


911 


N.  Rhaphoncis  =  Puinularia  Rhapho- 
neis,  EM.  pi.  .35  a.  9.  f.  7.  Ganges. 
Minute,  oblong',  with  subacute  apices,  a 
small  central  nodule,  and  diverging  stri;T3. 

N.  eunjsoma  (E.). — Minute,  smootb, 
elliptic,  VN^itli  rounded  ends,  and  marked 
by  two  narrow,  longitudinal  blank  lines, 
which  converge  at  each  end  and  are 
connected  at  the  centre  by  the  transverse 
nodule.  EB.  1838.  =  Stauroneis  itiry- 
soma,  EM.  pi.  21.  f.  3G.  Fossil.  Algiers. 
Apparently  more  allied  to  the  Ija-ate 
group  of  Na\icula  than  to  Stauroneis. 

Species  ft'om  Ehrenherg,  hiown  to  us 
only  hy  name. 

N.  ceratostiyma,  N.  Jordani,  N.  Leyu- 


mcn,  N.  ampliilepta,  N.  ohUqita,  N.  turyida, 
N.  SencyalenMs,  N.  FalMandifs,  N.  Catha- 
rincB,  N.  conspersa,  N.  Sarann(i>,  N.  aida- 
cophcena,  N.  Barhadensis,  N.  Euryale, 
N.  lejitoceros,  N.  sphisropitera,  N.  Vibrio, 
N.  leptotei'mia, 

Pimndaria  affinis,  Ehrenberg  gives  30 
habitats.  It  may  be  a  form  of  Naviada 
affinis,  with  more  evident  strife. 

P.  amhiyua,  P.  australis,  P.  insidaris, 
P.  pleuronectes,  P.  Preissii,  P.  Fasus,  P. 
Phenana,  P.  Craticida,  P.  pterophama, 
P.  platysoma,  P.  Catharince,  P.  anomala, 
P.  Hempricliii,  P.  Licaarce,  P.  Capensis, 
P.Caffra,  P.  anfarctica,  P.  Folium,  P. 
micros2)Jienia,  P.  j^lewonectes,  P.  Arau- 
canice,  P.  Barhadensis. 


Genus  STAURO^^EIS  (Ehr.,  Khtz.).— Fnistules  simple,  free  in  fi-ont  view 
parallelogramic  ;  valves  \\ith  median  Line  and  nodules,  central  nodule  trans- 
versely dilated.  Stauraneis  differs  from  Na^dcula  in  ha^dng  the  central 
nodule  prolonged  into  a  transverse  pellucid  band  (stauros)  free  from  stria). 
"In  a  few  cases  we  meet  ^\ith  the  semblance  of  a  stauros  in  the  genus 
Pinnularia  [i^avicula]  ;  but  in  these  instances  a  closer  examination  wiU  show 
that  this  appearance  arises  from  the  interruption  of  the  costag  merely,  and 
not  from  the  dilatation  of  the  central  nodule,  which  is  still  found  unchanged  " 
(Smith).  Ehi-enberg  dixides  this  genus  into  Stauroneis  and  Staiu'optera — the 
former  having  smooth,  and  the  latter  striated  frustules ;  but  we  agree  with 
Professor  Kiitzing  in  thinking  the  distinction,  as  in  Navicula  and  Pinnularia, 
unsatisfactory,  and  that  many  species  would  be  referred  by  the  observer  to 
the  one  or  other  genus  according  to  the  magnifying  power  of  the  microscope 
used  in  the  examination. 

S.  Leyumen  (E.).  —  Small,  oblong- 
lanceolate,  each  margin  with  three  uii- 
didations;  apices  apicidated ;  stauros 
linear,  reaching  the  margin.  EB.  1844, 
p.  135  j  EM.  pi.  39.  3.  f.  104;  Greg. 
MJ.  iv.  pi.  1.  f.  9.  =  Stauroneis  linearis, 
SD.  i.  p.  60,  pi.  19.  f.  193.  America, 
Europe. 


*   Valves  constricted  at  the  centre. 

SxAunoisrEis  constricta  (E.). — Small, 
oblong,  deeply  constricted  at  the  centre, 
and  slightly  contracted  into  obtuse 
apices.  EA.  p.  134,  pi.  1.  2.  f.  12  6. 
Chili,  Australia,  Africa. 

S.  Rabenhorstii. — Linear,  mth  broadly 
rounded  ends  and  concave  sides;  costse 
stout,  oblique;  stauros  linear.  =  Stattro- 
ptera  constricta,  Rab  D.  p.  50,  pi.  9.  f.  10. 
Italy. 

2*   Valves  with  2  or  S  imdidations. 

S.  injlata  (K.). — Small,  linear,  with 
tvro  constrictions,  and  three  dilatations; 
ends  broadly  roimded;  stauros  linear, 
reaching  the  margin.  KB.  p.  105,  pi.  30. 
f.  22.     Trinidad.     1-480"  to  1-428". 

S.  FulmeniVtvoh.). — Lanceolate,  acute, 
with  two  undulations;  stauros  ver}^ 
slightly  dilated  towards  the  margin ; 
strife  distinct,  22  in  -001" ;  front  view 
rectangular.  -008"  to  -015".  TM.  vii. 
p.  180,  pi.  9.  f.  6.  Fresh  water.  Mel- 
bourne. This  beautiful  species  resembles 
S.  acuta,  but  is  easily  distinguished  by 
its  marginal  undulations. 


(\Ti.  67.) 
3*   Vcdves  with  a  siymoid  median  line. 

_  S.  Siyma^  (E.).  —  Stout,  lanceolat.-, 
sigmoid,  with  obtuse  apices :  stauros 
abbreviated.  EB.  1844,  p.  88 ;  EM. 
pi.  18.  f.  63.  Fossil.  Eichmond  deposit. 
It  has  the  form  and  size  of  Pleurosiyma 
acuminatum',  but  its  median  nodule  is 
dilated,  as  if  geminate.     1-240".     Ehr. 

S.  obliqua  (Greg.).  —  Small,  short,  ob- 
long, or  broadly  lanceolate,  with  a  sigmoid 
or  oblique  median  line  ;  stauros  reachino* 
the  margin  ;  stria3  fine,  45  in  -001".  MJ. 
iv.p.  10,  pi.  1.  f.35.  Lochleven.  (vii.63.) 

4*   Valves  with  rostrate  or  capitate 
apices. 

S.  dilatata  (E.).— SmaU,  ventricose, 
\A\\\  minute,  mammiform  beaks  ;  stauros 


912 


SYSTEMATIC  HISTORY  OF  THE  INTFSOEIA. 


linear,  nearly  reaching  the  maroiu.  EA. 
pi.  1.  2.  f/l2«;  si),  i.  p.  60,  pi.  19. 
f.  191.     America,  Australia,     (xii.  16.) 

S.  exilis  (K.). — Very  minute,  ventri- 
cose,  shortly  rostrate ;  stauros  linear. 
KB.  p.  105,  pi.  30.  f.  21.  Trinidad. 
1-2400". 

S.  imndata  (K.).  —  Small,  ventricose, 
with  rostrate  apices,  and  27  radiant 
pimctate  strise  in  -001"  ;  stauros  linear, 
abbreviated.  KB.  p.  106,  pi.  21.  f.  9  ^ 
SB.  i.  p.  61,  pi.  19.  f.  189.  Britain. 
Fossil,  Santa  Fiore. 

S.  anccp8  (E.).  —  SmaU,  lanceolate, 
constricted  beneath  the  subcapitate 
apices  j  stauros  linear,  not  reaching-  the 
margin  ;  striae  very  delicate,  45  in  -001". 
EA.  p.  134,  pi.  2.1.  f.  18;  SB.  i.  p.  60, 
pi.  19.  f.  190.  Europe,  Asia,  Africa, 
America. 

S.  Crucicula  (S.).  —  Small,  elliptic- 
lanceolate,  somewhat  ventricose,  pro- 
duced at  the  ends  into  minute,  conical 
beaks;  stauros  very  narrow,  linear, 
reaching  the  margin.  SB.  i.  p.  60,  pi.  19. 
f.  192.     Marine.     Ireland,     (vii.  64.) 

S.  ventricosa  (K.).  —  Very  minute, 
ventricose,  constricted  beneath  the  capi- 
tate apices  ;  stauros  linear,  not  reaching 
the  margin.  I^.  p.  105,  pi.  30.  f.  27. 
Germany,  France,  Britain. 

S.  capitata  (E.). — Very  small,  oblong, 
twice  as  long  as  broad,  suddenly  con- 
stricted beneath  the  capitate  apices; 
stiia3 18  in  1-1560".  EB.  1844.  Southern 
Ocean.     Front  ^dew  linear.     1-1152". 

S.  phyUocles  (E.). — Turgid-lanceolate, 
with  the  apices  produced  into  short, 
subacute  beaks  ;  staiu^os  linear,  reaching 
the  margin.  EA.  p.  135,  pi.  1.  2.  f.  lO". 
America,  China,     (xii.  7-9.) 

S.  Semen,  EM.  pis.  35  a,  and  38  a. 
many  figures.  Ehrenberg  gives  about 
80  habitats  in  Asia,  Africa,  and  Ame- 
rica. Lateral  view  small,  ventricose, 
with  mammiform  apices  and  linear 
stauros. 

S.  Tmcula  (E.).  —  Small,  striated, 
elliptic-oblong;  apices  suddenly  con- 
tracted, umbonate  ;  stauros  linear,  reach- 
ing the  margin ;  strise  oblique.  =  Navicula 
Tusmla,  EB.  1840,  p.  21 ;  KA.  p.  77 ; 
Staiiroptera  Tuscida,  EM.  pi.  6.  1.  f.  13. 
Fossil.  Santa  Fiore,  Siberia.  Front 
view  linear. 

S.  mesopacJiya,  EM.  pi.  15  a.  f.  26. 
Lough  Mourne  deposit.  Large,  oblong- 
lanceolate,  suddenly  contracted  into  mam- 
mifonn,  obtuse  apices ;  stauros  linear. 

S.  hirostris  (E.).  —  Small,  narrow- 
lanceolate,  with  produced,  rostrate,  sub- 
acute apices ;  stauros  linear.   EA.  p.  134, 


pi.  2.  2,  f.  1.     America,  Africa. 

S.  Platalea  (E.). — Lateral  view  slender 
lanceolate^  constricted  beneath  the  capi- 
tate apices  ;  stam-os  linear.  EM.  pi.  \bK.% 
f.  30.     Lough  Mourne  deposit ;  Mexico. 

S.  SiehokUi  (E.).  —  Large,  turgid- 
lanceolate,  tapering  into  obtuse  beaks; 
stauros  linear.  EM.  pi.  34.  8.  f.  12. 
Japan. 

S.  Ehrenherc/ii  (E.).  —  Small,  inflated, 
oval,  with  produced,  mammiform  apices  ; 
stauros  linear;  striae  parallel.  =  Stau- 
roptera  platystoma,  EM.  pi.  14.  f.  13. 
Berlin. 

S.  platy stoma  (E.,  K.).  —  Linear-ob- 
long, contracted  at  the  ends  into  mammi- 
form beaks ;  stauros  linear.  JOB.  p.  105, 
pi.  3.  f.  58;  EM.  pi.  3.  1.  f.  S.=Navicula 
platystoma,  E  Inf.  pi.  13.  f.  8.  Germany, 
America,  Asia.  (ix.  142.)  1-1100"  to 
1-240". 

S.  ampliicephala  (K.). — Linear-oblong, 
with  produced,  rostrate,  capitate  apices ; 
stauros  linear.  KB.  p.  105,  pi.  30.  f.  25. 
Germany,  France. 

S.  linearis  (E.).  —  Minute,  linear-ob- 
long, with  parallel  marginal  lines,  at- 
tenuated at  the  apices  into  somewhat 
obtuse  beaks ;  stam*os  linear.  EA.  p.  135, 
pi.  1.  2.  f.  11.  America,  Em'ope.  Lough 
Mourne  deposit. 

S.  macrocephala  (K.). — Linear,  slen- 
der, constricted  beneath  the  capitate 
apices ;  transverse  strise  very  dense. 
KA.  p.  92.  =  Stauroptera  macrocephala, 
Rab  B.  p.  49.     France.     1-425". 

S.  2jlatycep)hala  =  Staiiroptera  platyce- 
phala,  EM.  pi.  17.  2.  f.  9.  Fossil.  Fin- 
land. Linear,  suddenly  constricted  be- 
neath the  dilated,  broadly  rounded  ends ; 
stauros  linear,  reaching  the  margin; 
striae  parallel. 

S.  excellens  (Perty). — Striated,  broadly 
linear,  suddenly  contracted  into  broadly 
rounded,  mammifonn  beaks.  Pertv,  Inf. 
p.  205,  t.  17.  f.  11.  Alps.  Form  and 
size  of  S.  jjlatystoma,  but  striated.  Its 
nearest  ally  is  S.  microstaiiron,  E. ;  but  it 
is  larger  and  somewhat  broader,  with 
less  broadly  roimded  ends. 

S.  microstaiiron  (E.,  K.).  —  Striated, 
linear,  suddenly  constricted  beneath  the 
broadly  rounded,  subcapitate  apices; 
stauros  linear.  KB.  p.  106,  pi.  29.  f.  13. 
=  Staiiroptera  microstanron,  EA.  pi.  1.  4. 
f.  1.     Asia,  Africa,  America. 

S.  monoyramma  (E.). — Oblong",  turgid 
at  the  middle,  and  conti'acted  at  each 
end  into  a  broad,  rounded,  conical  beak. 
EA.  p.  135;  IvB.  p.  105,  pi.  29.  f.  18. 
Surinam.  Eesembles  Achianthes  ven- 
tricosa. 


or  THE  NAVICTJLE^. 


913 


S.  gramdata  (E.).  —  Bacillar,  with 
turgid  middle  and  obtuse  ends;  trans- 
verse striae  granulated.  =  Stauroptera 
gramdata,  EB.  1847,  p.  484.  Canton. 
1-480".  Allied  to  Fragdaria  ?  inesotylu, 
and  to  Acknantlies  ventricosa. 

5*   Valves   neither    cojistricted,    rostrate, 

nor  furnisJied  ivith  a  sigmoid  median 

line, 

t  Valves  lanceolate. 

S.  Plioenicenteron  (Nitzsch.,  E.).  — 
Large,  broadly  lanceolate  or  somewhat 
rhomboid,  gi-adually  attenuated  into 
rather  obtuse  apices;  stauros  slightly 
dilated  outwards,  reaching  the  margin ; 
sti'ise  fine.  EA.  pi.  2.  5.  f.  1;  SD.  i. 
p.  59,  pi.  19.  f.  186.  =Bacillaria  Phceni- 
centeron,  Nitzsch ;  CymheUa  Phoenicen- 
teron,  AD,  p.  10;  Navicula  Phcenicen- 
t£ro7i,  E  Inf.  Common.  Europe,  Asia, 
Airica,  America,  (ix.  139  ;  xn.  17,  18.) 
1-400"  to  1-140". 

^.  pteroidea  (E.). — Large,  broadly  or 
sharply  lanceolate,  with  obtuse  apices, 
and  very  fine,  punctated,  transverse 
striae ;  stauros  linear,  reaching  the  mar- 
gin. EA.  p.  135;  EM.  pi.  3.  3.  f.  7. 
America.  Akin  to  S.  Baileyi;  larger 
than  >S'.  Phoenicenteron,  E. 

S.  Bailey i  (E.). — Large,  broadly  lan- 
ceolate, tapering  gradually  to  the  obtuse 
apices ;  surface  with  very  fine  longi- 
tudinal, undulated  lines  ;  stam*os  linear, 
reaching  the  margin.  EA.  p.  134 ;  EM. 
several  fignres.  America.  Akin  to  8. 
Plicenicenteron  and  S.  pteroidea,  E. 

S.  amphilepta  (E.). — Lanceolate,  little 
acuminated,  with  obtuse  apices ;  stauros 
linear;  striae  none,  or  indistinct.  EA. 
pi.  1.  2.  f.  9-13.  America,  Africa, 
feiberia.  It  is  scarcely  distinct  from  S. 
Plioenicenteron. 

S.  gracilis  (E.).  —  Slender-lanceolate, 
gi-adually  attenuated  into  obtuse  apices ; 
stam-os  linear,  scarcely  reaching  the 
margin;  striae  indistinct,  verv  delicate. 
EA.  pL  1.  2.  f.  14;  SD.  i.  p.  59,  pi.  19. 
f.  186.  America,  Europe,  Asia,  Africa. 
Smaller  and  more  slender  than  the  pre- 
ceding species. 

S.  apiculata  (Grev.). — Oval,  obtusely 
apiculate;  stauros  linear,  abbreviated; 
striae  fine,  34  in  -001".  Edin.  New  Phil. 
Journ.,  U.S.,  x.  pi.  4.  f.  8.  Californian 
guano.  Inflated,  suddenly  contracted  at 
the  ends  into  conic  beaks;  stauros  not 
reaching  more  than  halfway  from  the 
median  line  to  the  margin. 

S.  lanceolata  (K.).  —  Slender-lanceo- 
late, tapering  into  the  narrow,  subrostrate 


ends ;  stam'os  linear,  reaching  the  mar- 
gin ;  striae  obsolete  or  indistinct.  KB. 
p.  104,  pi.  30.  f.  24.  Falaise.  1-180" 
to  1-160". 

S.  Atlantica  (E.). — Small,  lanceolate, 
with  obtuse  apices ;  front  view  linear. 
EB.  1845,  p.  155.  In  pumice  from  the 
Isle  of  Ascension.  Akin  to  S.  amphilepta, 
but  more  obtuse.     1-1152". 

S.  salina  (Sm.). — Small,  slightly  con- 
tracted at  the  obtuse  apices;  stauros 
linear,  nearly  reaching  the  margin  ;  striae 
faint,  45  in'  -001".  SD.  i.  p.  CO,  pi.  19. 
f.  188.     Marine.     Britain. 

S.  minuta  (K.). — Smooth,  lanceolate, 
rather  obtuse,  three  times  as  long  as 
broad.    KA.  p.  89.    Thuringia.    1-1200". 

S.  duhia  (Greg.).  —  Minute,  smooth, 
nan'ow -lanceolate,  with  somewhat  trim- 
cate  apices ;  stauros  linear,  nearly  reach- 
ing the  margin.  MJ.  iv.  p.  11,  pi.  1. 
f.  37.  Scotland.  When  examined  under 
a  high  power,  the  valve  exhibits  two 
parallel  lines  within  the  margin  on  each 
side. 

S.  staurophccna  (E.).  —  Lanceolate, 
smooth,  slightly  conti-acted  at  the  sub- 
acute apices  ;  stauros  linear,  not  reaching 
the  margin.  EA.  p.  135 ;  EM.  pi.  2. 3.  f.  11. 
North  America.  Distinguished  from  S. 
Phcenicenteron  by  its  abbreviated  stauros. 

S.  Gregbrii  (Ralfs).  —  Rhomboid-lan- 
ceolate, Mdth  acute  apices ;  stauros  linear, 
reaching  the  margin ;  striae  fine,  nearly 
parallel,  60  in  •OQV'.^Staiironeis  am- 
phioxys,  Greg.  TM.  iv.  p.  48,  pi.  5.  f.  23. 
Scotland.  Highly  convex,  and  even  in 
the  best  position  showing  the  margin  as 
a  broad  black  line,  Greg. 

S.  inanis  (Perty). — Striated,  lanceo- 
late or  elliptic-lanceolate,  with  very  fine 
transverse  striae.  Perty,  Inf.  p.  206,  pi.  17. 
f.  7.  Alps.  In  form  nearly  agreeing  with 
S.  linearis,  E.,  but  striated. 

S.  lineolata  (E.). — Broadly  lanceolate, 
with  obtuse  apices,  and  parallel,  dotted, 
longitudinal  lines ;  stauros  linear.  EA. 
p.  135,  pi.  2.  1.  f.  19.     Cayenne. 

S.  pumila  (K.). — Minute,  elliptic-lan- 
ceolate, with  acute  apices,  and  short, 
marginal,  punctated,  transverse  striae ; 
stauros  reaching  the  margin.  KB.  p.  106, 
pi.  30.  f.  43.  Marine.  Christiania.  Front 
view  linear,  with  rounded  angles  and 
truncate  ends.     1-1440"  to  1-1080'. 

S.  Achnanthes  (E.,  K.).  —  Lanceolate, 
with  obtuse  apices ;  striae  distinct,  ob- 
lique ;  stauros  linear,  reaching  the  mar- 
gin. KB.  p.  106,  t.  29.  f.  22.  =  Stauroptera 
Achnanthes,  EA.  p.  135,  pi.  3.  3.  f.  7; 
EM.  pi.  17.  1.  f.  10.  Austi-alia,  Ame- 
rica, Falaise. 

3jff 


914 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


S.  truncata  (Eab.)-  — Minute,  oblong- 
lanceolate,  with  very  obtuse  apices ; 
staiu'os  linear;  stride  distinct,  oblique, 
14  or  15  in  l-l'200".  =  Stauro2)tera  trun- 
cata, Rab  D.  p.  49,  pi.  9.  f.  12.     Bosnia. 

S.  acrocephala  (Rab.). — Broadl}^  lan- 
ceolate ;  tiu'gid  at  the  middle,  rapidly 
tapering  to  the  acute  apices;  stauros 
dilated  outwards,  reaching  the  margin  ; 
strife  punctate,  parallel.  Rab  D.  p.  48, 
pi.  9.  f.  19.     Saxony. 

S.  acuta  (S.).  —  Elongated  slender- 
lanceolate  or  rhomboid,  tapering  to  the 
subacute  apices ;  stauros  conspicuously 
dilated  outwards,  reaching  the  margin  ; 
strife  oblique,  30  in  -001".  SD.  i.  p.  59, 
pi.  19.  f.  187.     Britain,     (vii.  76.) 

S.  pulchella  (S.).  —  Lanceolate,  or 
linear-lanceolate ;  stauros  conspicuously 
dilated  outwards,  reaching  the  margin  ; 
stride  oblique,  very  distinct,  punctate, 
80  in  -001".  SD.  i.  p.  61,  pi.  19.  f.  194. 
Marine.  Britain.  (vii.  77.).  Front 
view  broad,  linear-oblong,  with  rounded 
angles  and  constricted  centre. 

S.  asjm-a  (E.,  K.). — Turgid,  lanceo- 
late or  linear-lanceolate,  with  subacute 
apices ;  striae  oblique,  punctate-asperate ; 
stam'os  abbreviated,  dilated  outwards. 
KB.  p.  \0Q.  =  8tauroptera  aspera,  EA. 
p.  134,  pi.  1.  1.  f.  12  ;  BC.  vii.  pi.  1.  f.  18. 
America,  Europe.  Front  view  linear, 
with  trmicate  ends. 

2t  Valves  oval  or  oblong. 

S.  Fenestra  (E.). — Small,  elliptic-ob- 
long, with  parallel  marginal  lines,  and 
obtuse,  cmieate  apices.  EA.  pi.  2.  1. 
f.  20.     America,  Japan. 

S.  Peckii  (Rab.). — Small,  oval,  with 
rounded  ends;  costse  stout,  11  or  12  in 
1-1200";  stauros  linear,  reaching  the 
margin.  =  Stauroptera  Peckii,  Rab  D. 
p.  49,  pi.  9.  f.  18.     Lusatia. 

S.  pohjfframtna  (E.). — Elliptic-oblong, 
with  rounded  ends  and  longitudinal 
dotted  lines  ;  stauros  abbreviated.  EA. 
p.  185,  pi.  2.  6.  f.  80.     Cuba. 

S.  semicruciata  (E.). — Very  large,  re- 
sembling Navicula  viriclis,  but  having  the 
crucial  umbilicus  of  Stauroneis.  =  *Sf«?/- 
roptera  semicruciata.  EB.  1843,  p.  45. 
Asia. 

3t  Valves  linear. 

S.  dendrohates  (E.).  —  Narrow-linear, 
with  obtuse  ends,  and  a  densely  and 
obliquely  striated  border:  front  view 
oblong-quadrate.  =  Stauroptera  dendro- 
hates, E.  Under  moss  on  trees.  America. 
1-490". 

S.  Roraim(7>  =  Staurojytera   Roraimcp., 


EM.  pi.  34.  5  a.  f.  9.  Linear,  with  cu- 
neate  ends,  a  transverse  median  line,  and 
parallel  striae. 

S.  ohlonga  (Bail.). — Linear,  with  acute, 
cuneate  ends,  and  oblique  punctato-as- 
perate  striae ;  stauros  abbreviated,  dilated 
outwards.  =  Stauroptera  ohlonga,  BC.  vii. 
p.  10,  pi.  1.  f.  17.  America.  The  size 
and  markings  of  Stauroptera  aspera, 
E.,  but  having  its  valves  oblong,  with 
parallel  sides,  and  acute  angular  ends, 
Bailey. 

S.  Isostauron  (E.,  K.).  —  Elongated, 
linear,  with  broadly  rounded,  slightly 
attenuated  ends ;  stauros  linear,  reaching 
the  margin ;  striae  parallel.  KB.  p.  106. 
=  Stauroptera  Isostauron,  EA.  p.  135  ; 
EM.  pi.  16.  1.  f.  7.  Labrador,  Sweden, 
Finland,     (xii.  73.) 

S.  Liostauron  (E.). — Styliform,  linear- 
oblong,  with  scarcely  attenuated,  rounded 
apices ;  stauros  linear.  EA.  p.  135 ; 
EM.  pi.  5.  1.  f.  16.     Iceland. 

Douhtful  Species. 

S.  ?  explicata  (Perty).  —  Small,  not 
striated,  with  rounded  ends,  and  much 
inflated  centre  (cruciform) ;  enlarge- 
ments acute.  Perty  Inf.  p.  205,  pi.  17. 
f.  10,  Alps.  About  the  size  of  S.  ren- 
tricosum,  K.,  but  stiU  more  inflated  at 
the  middle,  and  the  inflations  pointed, 
not  romided,  Perty.  The  figm-e  has  no 
median  line  or  other  markings,  and  re- 
sembles a  Biblarimn  rather  than  a  Stau- 
roneis. 

S.  mesogongyla  (E.).  —  Lateral  view 
linear,  with  rounded  ends  and  gibbous 
centre;  transverse  striae  parallel,  inter- 
rupted by  a  transverse  central  band. 
Probably  a  Navicula,  since  tlie  figure 
shows  a  small,  definite  central  nodule. 
EM.  pi.  6.  1.  f.  7.  Guiana.  Fossil,  San 
Fiore. 

S.  gibha  (E.,  K.). — Form  of  Navicula 
gihha,  but  furnished  with  an  imperfect 
transverse  fascia.  KB.  p.  107,  pi.  29. 
f.  24.  =  Stauroptera  ?  gibha,  EA.  p.  135, 
pi.  1.  2.  f.  3.  America,  Africa.  The 
figure  represents  a  Navicula  with  the 
striae  shorter  opposite  the  dilated  um- 
bilical space. 

S.  paucicostata  (Rab.). — Small,  linear, 
with  inflated  centre,  and  dilated,  rounded 
apices  ;  costae  distant,  4  or  5  in  1-1200", 
much  inclined.  =  Stauroptera  pauci- 
costata, Rab  D.  p.  49,  pi.  9.  f.  15.  Eu- 
rope. The  figure  shows  a  rhomboid 
umbilical  space  resembling  the  dilated 
nodule  seen  in  many  Naviculae,  but  not 
a  true  stauros. 

S.    maculata    (Bail.).  —  Oval,    with 


OF  THE  NAYICULE^. 


915 


slightly  produced,  mammiform  apices ; 
surface  punctato-striate,  with  a  large 
smooth  central  space.  BMO.  p.  40, 
pi.  2.  f.  32.  Florida.  Resembles  -S: 
punctata,  K.,  but  is  larger,  and  has  the 
ends  not  so  much  produced.  The  figiu-e 
shows  a  dilated  umbilical  space  rather 
than  a  true  stauros. 

S.  scalaris  (E.,  K.). — Small,  linear- 
oblong,  with  roimded  ends  -,  costto  stout, 
parallel,  12  in  1-1200",  not  reaching  the 
median  line.  KB.  p.  10Q.  =  Stauroptera 
scalaris,  EA,  pi.  4.  2.  f.  3.  Labrador, 
(xii.  10,  14,  30.)  Scarcely  belonging  to 
this  genus,  since  Ehrenberg's  figures  show 
a  definite  central  nodide.  It  diiFers  from 
Navicula  horealis  by  its  coarser  costae  and 
their  inteiTuption  opposite  the  median 
nodide. 

S.  amp1iioxys  =  Stam'optera  amphioxys, 
EM.  pi.  6.  1.  f.  14.  Fossil.  Santa  Fiore. 
Ehrenberg's  figure  represents  an  elon- 
gated, narrow-lanceolate  Navicula,  with 
acute  apices^  and  a  minute  central  nodule 


I  which  is  not  dilated  into  a  stam-os ;  striae 
radiant.  <« 

I       S.  peregrina  =  Stauroptera  peregrina, 

\  EM.  pi.  6.  1.  f.  15.  Fossil.  Santa  Fiore. 
Ehrenberg's   figure  represents  a   small, 

I  lanceolate  Navicida,  with  a  minute 
central   nodule,   but   no   stauros ;  striae 

!  radiant. 

I  S.  ?  ovalts  (Greg.). —  Small,  smooth, 
oyal ;  stam'os  broad,  indistinct,  reaching 
the  margin.  MJ.  iv.  p.  11,  pi.  1.  f.  36. 
Britain.     Perhaps  a  Cocconeis. 

;       Species  fro7n  JElirenhei^g  known  to  us 
only  hy  name. 

S.  pusilla,  S.  splicerophoron,  S.  Indica, 
S.  Placentida,  S.  Hologramma,  S.  gihhosa, 
S.  JEthioinca,  S.  A^njjhisbcpna,  S.  Capensis, 
\  S.  GaJapagica,  S.  decurrens,  S.  hrevirostris, 
;  Stauroptera  nohilis,   Stauroptera  leptoce- 
pluda,    Stauroptera  Distauridiwn,    Stau- 
roptera Braziliensis,   Stauroi^tera   Tabel- 
laria,  S.  asperula,  Staurojytera  Siamensis, 
}  Stauroptera  trinodis. 


Genus  STAUROGRAMMA  (Rab.). — Like  Staiironeis,  but  with  decussating 
strioe,  and  prominent  knots  at  the  intersections,  Rab. 

Stauhogramma  Persicum  (Rab.). —  median  line  dilated  towards  the  ends. 
Oblong-lanceolate,  with  trmicate  apices ;  Rab  D.  p.  50.  =  Stauroptera  decussata, 
stam-os    linear,   reaching    the    margin;    Rab  D.  pi.  9.  f.  14.     Persia,     (vin.  36.) 


Genus  PROROSTAUROS  (E.).  —  Frustules  simple,  free ;  with  the  cha- 
racters of  Stauroneis,  except  that  its  terminal  puncta  in  the  front  \iew  are 
approximate  and  not  lateral.  We  doubt  whether  this  genus  can  be  separated 
from  Stauroneis ;  for,  if  we  understand  Ehrenberg's  definition,  the  apparent 
position  of  the  terminal  puncta  depends  upon  the  greater  convexity  of  the 
lateral  valves,  which  therefore  appear,  in  the  front  view,  like  a  border  on 
each  side  of  the  connecting  zone,  and  the  puncta  are  within  the  angles.  The 
species  are  unknown  to  us.     EB.  1843,  p.  136. 

PROROSTAUROS  spkndens (E.).— River  I  P.  ?  suhulatus  ?  (E.).— Senegal,  Cape  of 
Senegal.  Good  Hope.     At  first  sight  it  reminds 

I  one  of  Gomphonema  gracile,  E. 

Genus  PLEUROSIPHONIA  (E.).  — The  characters  of  this  genus  are 
unknown  to  us ;  but,  from  Ehrenberg's  figure  of  P.  affinis,  we  think  it  is 
probably  identical  with  Mastogloia. 


Pleurostphonia  affinis  (E.).  —  Ob- 
long-lanceolate, with  capitate  ends,  me- 
dian line  and  nodules,  and  a  marginal 
band  of  transverse  striae.  EB.  1856, 
p.  32.  =  Fragilaria  Navicula,  E.  1841 ; 
EM.  33.  1.  f.  14.     Arabia,  Africa,  Pern. 


Species  knoivn  only  hy  oiame. 
P.  Amphishoena  (E.),  Ai*abia,  Africa, 
Peru,  Mexico ;  P.  fulva  (E.),  Arabia, 
Africa;  P.  Phcenicenteron  (E.),  Arabia, 
Africa ;  P.  Lihyca  (E.),  Africa ;  P.  ohtusa 
(E.),  Africa ;  P.  gracilis  (E.)  Afiica. 


Genus  PLEUROSIGMA  (Smith)  (Gyrosigma,  Eassall,  Babenhorst,  &c.). 
— Frustules  simple,  free,  elongated  ;  front  view  linear  or  lanceolate,  narrower 
than  the  lateral  view ;  valves  depressed  or  slightly  convex,  sigmoid  (rarely 

3n2 


916 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


straight),  with  a  sigmoid  median  line,  central  and  terminal  nodules,  and  fine 
decnssating  striae,  which  are  resolvable  into  dots.  Plenrosigma  is  distinguished 
from  Donkinia  and  Amphiprora  by  the  elongated-narrow  front  view  and 
more  depressed  valves.  The  median  line,  also,  is  sigmoid,  whilst  in  those 
genera  it  is  usually  straight,  or  appears  sigmoid  merely  from  the  twisting  of 
the  frustule.  This  genus  was  first  separated  by  Dr.  Hassall  from  N'avicula, 
under  the  name  of  Gyrosigma.  Hassall,  however,  Hke  Ehi-enberg,  erroneously 
considered  it  identical  with  the  Sigmatella  of  Kiitzing,  whereas  they  belong 
to  very  distinct  families ;  and  even  their  sigmoid  forms  belong  to  difi'erent 
surfaces,  Sigmatella  having  it  in  the  front,  and  this  genus  in  the  lateral  view. 
Gyrosigma  has  been  adopted  by  Eabenhorst  and  others ;  nor  do  we  think  the 
name  so  objectionable  as  to  render  its  rejection  necessary.  If,  then,  we  admit 
Professor  Smith's  name,  we  do  so  for  the  reasons  given  by  Brebisson  : — 
*'  Gyrosigma  (Hass.). — Peutetre  ce  dernier  nom  de  genre  n'etait-il  pas  bien 
convenable  selon  les  lois  de  la  nomenclature ;  dans  tous  les  cas,  il  est  certain 
que,  malgre  son  droit  de  priorite,  il  est  a  pen  pres  generalement  abandonne. 
D'ailleurs,  on  est  d'autant  moins  dispose  a  reprocher  ce  changement  de  nom 
a  M.  W.  Smith,  que  le  soin  tout  monographique  qu'il  a  apporte  a  I'etude  des 
nombreuses  especes  de  Plenrosigma  qu'il  a  decouvertes,  en  fait  un  genre  tout 
a  lui"  (BrebDC.  p.  17).  Ehrenberg  does  not  admit  Plenrosigma,  because  it 
^'  does  not  difier  in  its  physiological  characters  from  Navicula  "  (EB.  1854, 
p.  236). 

*  Frustules  rostrate.  2  f  Beaks  short,  stout. 


t  Beaks  filiform. 

Fi.BvrROSiGMA Fasciola  (E.,  S.). — Tur- 
gid-lanceolate, with  long  linear  beaks 
abruptly  curved  in  contrary  directions ; 
stria3  64  in  -001",  indistinct.  SD.  i.  p.  67, 
pi.  21.  £  211.  =  Ceratoneis  Fasciola,  E, 
Marine.  Europe,  (xii.  60,  61.)  Colour  of 
dry  valve  pale-pink.  1-430".  Mr.Somtt 
states  this  Diatom  near  Hull  is  very 
small,  the  markings  90  in  -001",  while 
those  from  Boston  in  Lincolnshire  are 
large,  with  only  50  striae  in  -001". 

P.  macrum  (S.). — Elongated  slender- 
lanceolate,  with  very  long  filiform  beaks 
curv^ed  in  contrary  directions ;  transverse 
strise  85  in  -001",  very  indistinct.  SD. 
i.  p.  67,  pi.  31.  £  276.*^  Brackish  water. 
England. 

P.  prolongatiim  (S.).  — Narrow-lance- 
olate, gradually  tapering  into  slender 
beaks  curved  in  contrary  directions ; 
transverse  striae  65  in  -001",  indistinct. 
SD.  i.  p.  67,  pi.  21.  £  212.  Marine. 
England. 

P.  arcuatum  (Donkin).  —  Turgid-lan- 
ceolate, straight,  with  long,  very  slender, 
strongly  arcuate  beaks  curved  in  con- 
trary directions ;  striae  obscure  ;  median 
line"^  straight,  central.  TM.  \i.  p.  25, 
pi.  3.  £  10.  Marine.  England.  Closely 
allied  to  P.  macrum,  but  distinguished 
from  it  by  the  long,  strongly  arcuate 
beaks.  Dry  valves  very  pale-brown. 
(Donkin.) 


P.  distortiim  (S.). — Stout,  turgid-lan- 
ceolate, produced  into  short,  broad,  ob- 
tuse, subrostrate  extremities,  which  are 
abruptly  bent  in  contrary  directions ; 
transverse  striae  obscure,  75  in  -001" ; 
median  line  central.  SD.  i.  p.  67,  pi.  20. 
£210.  Marine.  England.  Small;  colour 
pale  pink.     1-320". 

P.  uEstuarii  (Br^b.,  S.).  —  Broadly 
lanceolate,  rapidly  tapering  into  sub- 
rostrate, obtuse  ends ;  median  line  di- 
agonal, submarginal  near  the  ends  ;  striae 
oblique,  54  in  -001"  ;  colom*  pale  purple. 
SD.  i.  p.  m,^  pi.  31.  £  275.  =  Navi- 
cula  ^stuarii,  KA.  p.  890;  Gyrosigma 
jEstuarii,  Breb.  Marine.  Europe. 
Bather  small;  1-290".  Habit  of  P. 
Thuringicum,  but  smaller,  paler,  and 
without  the  marginal  notch,  Klitz. 

P.  littorale  (S.).  —  Turgid-lanceolate, 
rapidly  attenuated  into  the  cui-ved,  sub- 
rostrate, somewhat  acute  ends  ;  longitu- 
dinal striae  conspicuous,  24  in  *001", 
transverse  50  in  "001" ;  colour  pur- 
phsh.  SD.  i.  p.  67,  pi.  22.  £  214. 
Marine.  Eiu-ope.  1-200"  ;  median  line 
subcentral. 

2  *   Valves  gihhous  at  the  middle, 

P.  Sineiisis  (E.).  —  Large,  elongated, 
broadly  linear,  flexuose,  sigmoid,  with 
gibbous  centre  and  broadly  roimded, 
somewhat  incrassated  ends,  which  are 
curved  in  contrary  directions.  =  AV/nV«//a 


OF  THE  NAVICULE^. 


917 


Sinensis,  EB.  1847,  p.  484 ;  EM.  pi.  34.  7. 
f.  11.     China.     1-80". 

P.  r  ever  sum  (Greg.).  —  Elongated 
narrow-linear,  with  inflated  or  lanceolate 
centre,  and  dilated  ends  which  are  turned 
in  contrary  directions  ;  median  line  sig- 
moid, subcentral  except  near  the  ends ; 
striae  extremely  fine.  GDC.  p.  58,  pi.  6. 
f.  105.  Marine.  Scotland.  This  form 
may  be  identical  with  P.  Sinensis',  but 
the  valves  are  narrower  and  with  less- 
rounded  apices  than  in  Ehrenberg's 
figure  of  that  species. 

3  *   Valves  linear.   ■ 

P.  Balticum  (E.,  S.). — Large,  broadly 
linear,  straight,  except  towards  the 
attenuated  obtuse  ends,  which  are  curved 
in  contrary  directions  ;  longitudinal  and 
transverse  striae,  38  in  -001" ;  colour 
dark  brown.  SD.  i.  p.  66,  pi.  22,  f.  207. 
-Navicula  Baltica,  E  Inf.  pi.  13.  f.  10; 
Gyrosigma  Balticum,  Rab  I),  p.  47,  pi.  5. 
f.  6;  P.  makron,  Johnston,  MJ.  \\\\. 
Marine  or  brackish  waters.  Common, 
(vm.  33;  ix.  144.)  1-70".  Median 
line  flexuose,  subcentral 

P.  ohsctirum  (S.). — Small,  linear,  with 
attenuated,  rather  obtuse  ends ;  median 
line  very  flexuose,  not  central ;  striae  ob- 
lique, 75  in  -001".  SD.  i.  p.  65,  pi.  20. 
f.  206.  Marine  or  brackish  waters.  Britain. 
Var.  /3  smaller.  1-193" ;  colom-  pale  pink ; 
median  line  marginal  near  the  ends. 

P.  simum  (E.).  —  Small,  linear,  with 
the  ends  obliquely  rounded  on  opposite 
sides ;  median  line  sigmoid,  nearly  cen- 
tral. =  Navicula  sima,  EB.  1845,  p.  363 ; 
EM.  pi.  34.  7.  f.  9.     India.     1-430". 

P.  Scalpellum  (K.).  —  Small,  linear, 
slightly  sig-moid,  gradually  attenuated 
into  the  obtuse  apices  ;  median  line  svih- 
central.  =  Navicula  Scalpelhwi,  KA.  p.  85; 
KB.  pi.  30.  f.  13  ;  Gyrosigma  Scalpellum^ 
Rah  p.  p.  47,  pi.  5.  f.  10.  Trinidad, 
Persia. 

P.  Sciotoensis  (Sullivant).  —  Linear, 
moderately  sigmoid,  gTadually  attenu- 
ated into  the  rather  obtuse  ends ;  striae 
transverse  and  longitudinal,  40  in  '001". 
SiUiman's  J.  xxvii.  p.  251.  Fresh  water. 
United  States.  -001".  "NotimlikeP. 
Spencerii,  for  which  it  has  passed  as  a 
variety ;  but  it  is  a  larger  species,  with 
sides  more  parallel  and  ends  less  acute. 
Its  striation  at  once  distinguishes  it " 
(SuU.). 

4  *    Valves  lanceolate  or  linear-lanceolate. 
t  Valves  linear-lanceolate. 
P.  Wansheckii  (Donkin). — Linear-lMte 


ceolate,  \\dth  tapering,  subacute,  slightly 
sigmoid  ends ;  median  lines  sigmoid, 
not  central ;  longitudinal  and  transverse 
striae,  about  50  in  001".  Donkin,  TM. 
vi.  p.  24,  pi.  3.  f.  7.=  P.  Balticurn,  /3,  SD. 
Marine.  England.  Pale  straw-coloured. 
•0045"  to  -005".  Much  smaller  than  P. 
Balticum,  and  with  more  numerous  striae. 

P.  lamprocaynpum  (E.).  —  Slender, 
narrowly  linear-lanceolate,  tapering  to 
the  rather  obtuse  apices ;  sigmoid,  with 
fine  transverse  striae ;  median  line  cen- 
tral; front  view  Y\Vi&2x.— Navicula  lam- 
procampa,  EB.  1840,  p.  20 ;  KB.  p.  102, 
pl.  4.  f.  5  ;  Gyi-osigma  lamprocampum, 
Kab  D.  p.  47,  pl.  5.  f.  9.  Marine.  Europe, 
1-144". 

P.  curvulum  (E.). — Linear-lanceolate, 
with  rather  obtuse  apices,  sigmoid.  = 
Navicula  ciirvula,  E  Inf  pl.  13.  f.  14 ; 
Gyrosigma  curvulum,  Rab  D.  p.  47,  pl.  5. 
f.  8.     Em-ope,  America. 

P.  speciosum  (S.). — Linear-lanceolate, 
flexed  chiefly  at  the  somewhat  abrupt, 
obtuse  ends ;  median  line  submarginal 
near  the  ends  ;  striae  oblique,  44  in  -001" ; 
SD.  i.  p.  63,  pl.  20.  f.  197.  England. 
Pale  straw-colour.  1-85".  It  is  shorter, 
less  tapering,  and  has  more  rounded 
apices  than  P.  formosnm;  the  median 
line  also  is  not  diagonal  at  the  centre. 
^  V.formosum  (S.). — Large,  elongated, 
linear-lanceolate,  much  flexed,  gradually 
tapering  to  the  obtuse  apices ;  median 
line  diagonal ;  striae  oblique,  36  in  -001". 
SD.  i.  p.  63,  pl.  20.  f.  195.  Marine.  Eng- 
land. (^Tdi.  32.)  Colour  chestnut-brown. 
1-66".  Well  distinguished  by  the  po- 
sition of  its  median  line,  which,  owing 
to  a  twist  in  the  valves,  appears  to  coin- 
cide with  the  edges  for  a  considerable 
distance  at  either  end,  and  then  crosses 
in  a  diagonal  direction. 

P.  Longinum  (Bri.).  —  Lanceolate, 
flexm'e  moderate,  extremities  greatly 
elongated,  acute ;  median  line  central ; 
striae  transverse,  36  in  -001".  -020"  to 
•025".  Colour  pale  straw.  TM.  vii. 
p.  180,  pl.  9.  f.  7.     Arctic  regions. 

P  sinuosum  (E.).  —  Small,  striated, 
linear-lanceolate;  striae  15  in  1-1200". 
1-480".  =  Navicula  sinuosa,  EB.  1840, 
p.  21.  Marine.  Europe.  Has  the  figm*e 
of  P.  simum,  but  is  more  slender. 

P.  subtile  (Breb.). — Very  slender,  pel- 
lucid and  delicate  ;  slightly  sigmoid,  very 
narrow  linear-lanceolate,  subuliform  with 
rather  obtuse  apices.  =  Navicula  subtilis^ 
KA.  p.  87.  Marine.  France.  1-160" 
to  1-120". 

P.  tenuissimum  (S.).  —  Very  narrow 
linear-lanceolate,  gradually  tapering  to  a 


918 


SYSTEMATIC  HISTOEY  OF  THE  LN^FUSOEIA. 


fine  point ;  transverse  striae  48  in  -001" ; 
median  line  central.  SD.  i.  p.  67,  pi.  22. 
f.  213.     Brackish  water.     Essex. 

P.  Apidum  (Rab.).  —  Slender-lanceo- 
late, niucli  curved,  with  obtuse  ends, 
transversely  striated ;  front  view  broadly 
linear.  Rab  D.  p.  47,  pi.  5.  f.  7.  Italy. 
In  the  figiu-es  the  valves  are  linear,  very 
but  not  s}^llmetrically  sigmoid,  with 
tapering-  ends  and  central  median  line. 

2 1  Valves  lanceolate,  with  oblique  striae. 

P.  delicatidmn  (S.).  —  Slender-lance- 
olate, gTaduaUy  tapering  to  the  acute 
apices  ;  ilexm-e  moderate ;  median  line 
central ;  striae  oblique,  64  in  -001".  SD. 
i.  p.  64,  pi.  21.  f.  202.  Brackish  water. 
Britain.  Length  1-112";  breadth 
1-1500".     Colour  pale  pink. 

P.  injiatum  (Shadbolt).  —  Small, 
broadly-lanceolate,  with  acute  apices  ; 
median  line  central,  much  flexed,  as  well 
as  the'  valve ;  striae  oblique.  TM.  ii. 
p.  16,  pi.  1.  f.  9.     Marine.     Natal. 

P.  decorum  (S.).  —  Large,  elongated, 
rhomboid-lanceolate,  imiformly  flexed, 
gradually  tapering  to  the  subacute  apices ; 
striae  oblique,  36  in  -001" ;  median  line 
diagonal,  marginal  near  the  ends.  SD.  i. 
p.  63,  pi.  21.'  f.  196.  Brackish  water. 
England.     Colour  pale  chestnut. 

P.  amjidatum  (Quekett,  S.).  —  Large, 
broad,  sigmoid,  rhomboid-lanceolate, 
rapidly  tapering  to  the  subacute  apices ; 
median  line  somewhat  diagonal ;  stritie 
oblique,  52  in  -001".  SD.  i.  p.  65,  pi.  21. 
f.  205.  =  Navicida  angidata,  Quekett, 
Microsc.  p.  438,  pi.  8.  f.  4  to  7.  Marine. 
Britain.  Colour  pale  chestnut )  flexure 
moderate. 

P.  quadratum  (S.).  —  Large,  very 
broad  rhomboid,  rapidly  tapering  to  the 
subacute  apices,  which  are  slightly  flexed; 
striae  oblique,  45  in  -001" ;  median  line 
central.  SD.  i.  p.  65,  pi.  20.  f.  204.= P. 
amjidatum,  ANH.  2nd  series,  ix.  p.  7. 
Marine.  Em'ope.  Colom'  chestnut ; 
lengthl-llO"  ;  breadth  1-428".  Easily 
recognized  b3'its  very  broad  angular  form. 

P.  Janceolatum  (Donkin).  —  Straight, 
broadly  lanceolate,  acute ;  median  line 
straight  or  gently  sigmoid,  with  the  ter- 
minal nodules  tm'ned  in  contrary  direc- 
tions ;  strife  verv  fine,  oblique,  about  70 
in  -001".  TM.  ;i.  p.  22,  pi.  3.  f.  4.  =  P. 
transversale,  /3,  Mr.  Roper.  Marine.  Eng- 
land. Straw-coloured ;  -0055"  to  -006" : 
front  view  narrow  linear-lanceolate. 
The  extremely  fine  striae  require  the 
most  careful  manipulation  with  very 
obliqne  light,  to  render  them  visible  with 
a  superior  l-5th  objective. 


P.  navictdaceum  (Breb.).  —  Rather 
small,  lanceolate,  straight,  gradually 
tapering  to  the  obtuse  apices,  which  are 
slightly  tm'ned  in  contrary  directions  ; 
median  line  sigmoid,  not  central ;  striae 
very  fine,  oblique.  B.  Diat.  of  Cherbourg, 
1854,  p.  17,  f.  7.  =  Gyrosigma  transver- 
sale, Microg.  Diet.  pi.  11.  f.  37,  38 ;_  P. 
transversale,  SD.  ii.  p.  96.  Marine. 
Common,  especially  in  deep  waters.  This 
species,  \dewed  laterally,  greatly  resem- 
bles a  Navicida  in  its  lanceolate  straight 
fonn.  Its  apices  are  only  slightly  in- 
clined to  opposite  sides.  The  median 
line,  however,  is  sigmoid,  and  the  striae 
are  oblique  and  decussating. 

P.  marinum  (Donkin). —  Broadly  lan- 
ceolate, straight,  slightly  sigmoicl  near 
the  obtuse  ends  ;  median  line  sigmoid  on 
each  side  of  the  central  nodule ;  striae 
oblique.  TM.  vi.  p.  22,  pi.  3.  f.  .3.  Marine. 
Northumberland.  Straw-coloured ;  striae 
about  45  to  50  in  -001".  _  -0055"  to  -006". 
The  well-marked  sigmoid  flexm'e  of  the 
median  line  on  both  sides  of  the  central 
nodule  distinguishes  this  species,  and 
renders  it  easy  of  recognition. 

P.  Nuhecula  (S.). — Small,  lanceolate, 
nearly  straight,  with  obtuse  apices,  cen- 
tral median  line,  and  55  oblique  striae  in 
•001" ;  colour  veiy  pale.  SD.  i.  p.  64, 
pi.  21.  f.  201.     Marine.     England. 

P.  intermedium  (S.). — Elongated,  pale 
sti'aw-colom',  slender  lanceolate,  nearly 
straight,  tapering  to  the  subacute  apices  ; 
median  line  subcentral;  striae  oblique, 
55  in  -001".  SD.  i.  p.  64,  pi.  21.  f.  200. 
Marine.     England. 

V.  rigidum  {^.). — Large,  stout,  pale 
straw-colour,  lanceolate,  nearly  straight, 
with  rounded  apices ;  median  line  cen- 
tral; striae  oblique,  48  in  -001".  SD. 
i.  p.  64,  pi.  20.  f.  198.  Marine.  England. 

P.  validiim  (Sh.). — Large ;  lanceolate, 
nearly  straight,  with  very  obtuse  apices, 
oblique  striae,  and  slightlv  flexed  median 
line.  MT.  ii.  p.  16,  pi.  1.  f.  8.  Marine. 
Natal. 

P.  elongatum  (S.).  —  Large,  much 
elongated,  lanceolate,  gradually  tapering 
to  the  acute  apices,  nearly  straight,  ex- 
cept at  the  ends,  which  are  slightly 
curved ;  striae  oblique,  48  in  -001" ; 
median  line  nearly  straight.  SD.  i.  p.  64, 
pi.  20.  f.  199.  Marine.  England.  Clear 
straw-colour.  Length  1-75";  breadth 
1-920". 

P.  strigosum  (S.).  —  Large,  elongated, 
broadly  lanceolate,  gradually  attenuated 
to  the  obtuse  apices  ;  flexure  slight ;  me- 
dian line  not  central  near  the  ends ; 
^%  oblique,  44  in  -001".     SD.  i.  p.  64, 


OF  THE  NAYICULEiE. 


919 


pi.  21.  f.  203.  Marine.  Biitaiu.  1-90" ; 
colour  pale  straw ;  front  view  narrow 
linear-lanceolatO;  with  obtuse  apices. 

3  t  A'alves  lanceolate,  with  longitudinal 
and  transverse  strife. 

P.  obtusatum  (Sullivant).  —  Oblong- 
lanceolate,  slightly  sigmoid,  with  obtuse 
apices ;  -0025" ;  striae  transverse  and 
longitudinal,  56  in  -001".  Silliman's  J. 
xxvii.  p.  251.  Fresh  water.  United 
States.  A  very  small  species,  remark- 
able for  the  obtuse  ends.  It  may  be  a 
CoUetonema,  but  we  have  not  observed 
it  in  gelatinous  envelopes. 

P.  Spenceri  (Quekett,  S.).  —  Small, 
lanceolate,  moderately  flexed,  gradually 
tapering  to  the  obtuse  apices;  median 
line  central ;  striae  verv  tine,  transverse 
50  in  -001",  longitudinal  55  in  -001". 
SD.  i.  p.  68,  pi.  22.  f.  2l^.  =  Nai'icula 
Spenceri,  Quekett.  Fresh  water.  America, 
Europe.     Colour  pale  brown.     1-270". 

P.  Parkeri  (Harrison).  —  Lanceolate, 
considerably  flexed,  apices  produced, 
median  line  central ;  striae  transverse, 
55  to  60  in  -001";  longitudinal  striae 
faint ;  colom'  pale  yellow.  Lincoln- 
shire.    MJ,  viii.  p.  105. 

P.  IVormleyii  (Sidlivant).  —  Lance- 
olate, conspicuously  sigmoid,  suddenly 
attenuated  into  acute  apices ;  "003" ; 
striae,  longitudinal  and  transverse,  52  in 
•001".  Silliman's  J.  xxvii.  p.  251.  Fresh 
water.  United  States.  Resembles  P. 
Spenceri,  but  is  a  smaller  species,  more 
evidently  sigmoid,  and  with  rather  ab- 
ruptly attenuated  ends ;  its  striae  are 
more  difficult  to  resolve,  and  the  texture 
of  its  valves  is  thinner. 

P.  laciistre  (S.). — Lanceolate,  consider- 
ably flexed,  gradually  tapering  into  the 
obtuse  apices ;  longitudinal  and  trans- 
verse striaB,  48  in  -001";  median  line 
subcentral.  SD.  i.  p.  68,  pi.  21.  f.  217. 
Fresh  water.     England.     1-144". 

P.  TJiuringicum  (K.). — Lanceolate,  sig- 
moid, gradually  attenuated  to  the  sub- 
acute apices,  obsoletely  notched  at  the 
middle  of  each  margin ;  median  line 
central;  striae  wanting  or  indistinct.  = 
Navicula  Thuringica,  KB.  p.  102,  pi.  4. 
f.  27 ;  Gyrosigma  Thuringicum,  Rab  D. 
p.  47,  pi.  5.  £  4.  Thuriugia.  Front 
view  narrow-linear  ;  1-264"  to  1-168". 

P.  Agellus  (E.).  —  Large,  lanceolate, 
flexed,  gradually  tapering  to  the  obtuse 
apices,  marked  longitudinally  with  very 
fine  lines,  and  thus  appearing  furrowed  ; 
median  line  centra],  =  Nacicula  Agelhis, 
EB.  1840,  p.  18;  EM.  pi.  15  a.  f  31; 
Gyrosigma  Agellus,  Rab  1).  p.  47.    Fresh 


water.  Germany,  Lough  Mourne  deposit, 
Siberia.  Front  view  nearly  linear,  vdih 
subacute  apices  ;  180".  Is  more  slender 
and  longer  than  P.  Hippoccunpus,  E. 

P.  attenuatum  (K.,  S.). — Large,  elon- 
gated, flexed,  lanceolate,  gradually  at- 
tenuated into  the  obtuse  apices  ; "  lon- 
gitudinal strife  30,  and  transverse  40  in 
•001"  ;  median  line  central.  SD.  i.  p.  68, 
pi.  "1%  f.  "nQ.^i Navicula  attenuata,  KB. 
p.  102,  pi.  4.  £  28  ;  Gyrosigma  attenuatum, 
Rab  D.  p.  47.  Fresh  water.  Em'ope. 
1-120".  Colour  purplish  broTvm;  front 
view  narrow-lanceolate,  with  truncate 
ends. 

P.  cuspidatum  (Rab.).  —  Slender-lan- 
ceolate, very  much  flexed,  with  long, 
tapering,  obtuse  ends ;  median  line  cen- 
tral. =  Gyrosigma  cuspidatum,  Rab  D. 
p.  47,  pi.  5.  £  5,  6.  Fresh  water.  Europe, 
America.  It  is  always  mixed  with  P. 
acuminatum. 

P.  acuminatum  (K.,  S.). — Lanceolate, 
tapering  into  the  obtuse  apices ;  flexure 
considerable  ;  median  line  central ;  lon- 
gitudinal striae  40  in  -001",  transverse 
52  in  -001".  SD.  i.  p.  66,  pi.  21.  £  209. 
=  Navicula  acuminata,  KB.  p.  102,  pi,  4. 
£  2Q ;  Navicula  Sigma,  EB.  1843,  p.  209 ; 
Gyrosigma  Hassallii,  Rab  D.  p.  47. 
Marine.  Europe,  Asia,  Africa.,  America, 
(ix.  146.)  Front  view  narrow-linear, 
with  obtuse  apices  ;  1-162" ;  colour 
pale  brown. 

P.  Hippocampus  (E.,  S.).  —  Large, 
elongated,  broadly  lanceolate,  obtuse ; 
flexm-e  considerable ;  colour  pale  brown ; 
striae  as  in  P.  attenuatum ;  median  line 
central.  SD.  i.  p.  68,  pi.  22.  £  215.  = 
Navicula  Hipjjocampus,  E  In£  pi.  13.  £  9  ; 
Gyrosic/ma  Hippocampus,  HBA.  pi.  102. 
£  11 ;  Rab  D.  p.  47.  Marine.  Europe, 
(ix.  145.)  1-166"  ;  front  view  linear, 
truncate. 

P.  Strigilis  (S.).  —  Large,  much  elon- 
gated, lanceolate,  uniformly  tapering  to 
the  subacute  apices,  flexed ;  median  line 
central ;  striae,  transverse  and  longitu- 
dinal, 36  to  40  in  -001".  SD.  i.  p.  66, 
pi.  22.  £  208.  Brackish  water.  England. 
Length  1-80";  breadth  1-830" ;  colour 
pale  brown.  Notable  for  its  graceful 
form  and  distinct  striae. 

P.  Seal]) rum  (Gaillon).  —  Small,  sig- 
moid, gradually  attenuated  into  the 
rather  obtuse  apices,  longitudinally 
striated.  =  Cymhella  Scalprum,  AD.  p.  11 ; 
Navicula  Scalijrum,  E.  In£  ;  KB.  pi.  4. 
£  25.  Marine.  Europe,  xlsia,  America. 
Length  1-430"  to  1-290". 

P.  Normanii  (n.  sp.).  —  Broadly  lan- 
ceolate, slightly  flexed,  with  rather  ob- 


920 


STSTEIIATIC  HISTORY  OF  THE  INFUSORIA. 


tiise  ends,  and  a  slight,  transvei*se  cen- 
tral depression  }  median  line  stout,  nearly 
central ;  striae  oblique,  40  in  -001".  = 
P.  lanceolatmn,  Norman,  MS.  Marine. 
Europe.  Foimd  in  nearly  every  gather- 
ing from  deep  water,  and  in  stomachs 
of  Ascidians,  Noctilucse,  Pectens,  &c. 
Colour  ta^\^ly  brown ;  -0048"  to  -0110' ; 
median  line  scarcely  flexed,  except  near 
the  ends.     The  description  is  by  George 


Norman,  Esq. 

P.  aciitum  (Norman,  MS.^  —  Large, 
broadly  lanceolate,  elongated,  moderately 
flexed,  gradually  tapering  to  the  very 
acute  apices  ;  median  line  delicate,  much 
flexed,  not  central ;  strise  oblique,  50  in 
•001"  Marine.  Stomachs  of  Ascidians, 
&c.  Europe.  Very  pale  straw-colour  or 
nearly  hyaline  ;  -Oil"  ;  median  line 
flexed  throuo-hout. 


Genus  TOXONIDEA  (Donkin).  —  Erustules  simple,  free ;  lateral  valves 
elongated  convex,  with  the  sides  not  symmetrical ;  median  line  arcuate,  with 
central  and  terminal  nodules,  its  ends  curved  towards  the  same  margin  ; 
stride  obhque.  Marine.  Toxonidea  is  closely  allied  to  Pleiu-osigma  ;  indeed 
the  forms  placed  here  are  regarded  by  Professor  Amott  as  distorted  species 
of  that  genus.  The  absence,  however,  of  a  sigmoid  flexure,  both  in  the  valves 
and  median  line,  is  so  different  from  what  we  find  in  Pleurosigma,  that  we 
think  it  advisable  to  admit  Toxonidea  until  Dr.  Donkin's  views  are  disproved 
by  more  perfect  observation. 


Toxonidea  Gregoriana  ("Donkin). — 
Large,  lanceolate,  with  the  obtuse  ends 
curved  upwards  ;  median  line  concurrent 
with  the  lower  margin  near  the  ends  ; 
strise  tine,  oblique,  about  50  in  -001". 
TM.  vi.  p.  19,  pi.  3.  f.  1.  Britain.  Straw- 
coloured  ;  -008"  to  -009" ;  median  line 
curved  upwards  near  the  end,  and  "  re- 
sembling the  figm-e  of  an  unbent  Scy- 
thian bow ; "  dorsum  rather  more  con- 
vex than  the  venter. 

T.  insignis  (Donkin).  —  Arcuate  or 
semi-lunate,  with  produced,  subacute 
ends ;  median  line  not  central,  strongly 
arcuate  ;  striae  very  fine,  about  75  or  80 
in  -001".  TM.  Yi.  p.  21,  pi.  3.  f.  2.  -0048" 


to  -006" ;  "  valves  resembling  a  straw- 
coloured  strung  bow  or  a  cocked  hat," 
with  very  convex  or  gibbous  dorsum  and 
straight  venter.  Professor  Arnott  re- 
gards this  species  as  a  distorted  state  of 
Pleurosigma  .^Jstuaru.     Britain. 

T.midulata  (Norman,  3IS.). — Arcuate, 
with  three  slight  dorsal  undulations,  ob- 
tuse somewhat  recurved  apices,  and  con- 
cave venter  gibbous  at  its  centre ;  striae 
oblique,  50  in  -001".  From  Ascidians. 
North  Sea.  Very  pale  straw-colour,  Tvath 
pinkish  reflections  ;  '0055"  j  longitudinal 
suture  concm-rent  with  the  ventral  mar- 
gin except  at  the  inflated  centre,  (viu. 
46.) 


Genus  DONKINIA  (n.  g.).  —  Erustules  simple,  free ;  front  view  panduri- 
form,  as  broad  as  the  lateral  view ;  valves  convex,  keeled,  with  nodules  and 
decussating  striae  as  in  Pleurosigma.  Marine.  We  have  constituted  this 
genus  for  the  reception  of  some  Diatoms  possessing  characters  intermediate 
between  Pleurosigma  and  Amphiprora,  and  have  much  pleasure  in  dedicating 
it  to  Dr.  Donkin,  who,  amongst  his  many  interesting  discoveries,  first  directed 
attention  to  several  of  the  species  placed  in  it.  Dr.  Donkin  refen^ed  the 
species  to  Pleurosigma  on  account  of  the  similarity  of  striation ;  but  they 
dlfi'er  from  that  genus  in  the  broad,  constricted  front  view ;  and  from  these 
characters,  together  with  their  very  convex,  keeled  valves,  we  were  induced 
to  regard  them  as  more  nearly  allied  to  Amphiprora.  Indeed  there  is 
little  essential  difference  between  keel,  crest,  and  wing,  these  being,  in  our 
opinion,  merely  different  stages  of  development.  This  opinion  was  also 
adopted  by  Professor  Amott,  whose  critical  kno^^dedge  of  genera  commands 
the  highest  deference.  The  species  placed  in  Donkinia  differ  from  Amphi- 
prora, not  only  in  their  decussating  striae  (a  character  sometimes  difficult  to 
verify,  and  of  rather  doubtful  generic  value),  but  also,  according  to  Dr. 
Donkin,  in  the  absence  of  lateral  wings  to  the  valves. 


Donkinia  cristata  (E.). — Narrow-lan- 
ceolate, gradually  subulate  at  each  end  ; 


central  nodule  transversely  oblong ;  me- 
dian  line   sigmoid,   crested.  =  Navicula 


OP  TKE  NAYICTJLE.i:. 


921 


cnstata,  EB.  1854,  p.  240 ;  EM.  pi.  35 
BB.  4.  f.  13.     Atlantic. 

D.  inversa  (E.).  —  Short,  narrow,  sig- 
moid, with  subacute  apices ;  front  view 
very  broad,  quadrangular,  constricted  at 
the  middle,  with  broadly  truncate  ends 
and  marginal  glands.  =  iVflric«</a  inversa, 
EB.  1840,  p.  18.  Europe.  1-576".  "  It 
is  allied  to  Amphiprora  alata,  but  wants 
the  winged  portions"  (E.). 

D.  carinata  (Donkin). — Straight,  linear- 
lanceolate,  acute,  very  convex ;  colour 
dull  pui-ple;  median  line  strongly  sig- 
moid, marginal  near  each  end  j  striae 
oblique,  fine,  about  55  to  60  in  -001".  = 
Pleurusigma  carinatum,  Donkin,  I.  c.  p.  23, 
pi.  3.  f.  5.  England.  -0046";  valve 
twisted ;  median  line  diagonal  at  the  cen- 
tre, marginal  near  the  ends.    (\T:n.  49.) 

I),  compact  a  (Grev.).  —  Straight,  very 
convex,  linear,  obtuse,  sigmoid  from 
having  the  ends  sloped  in  contrary 
directions  ;  median  line  much  flexed, 
diagonal  at  the  centre,  marginal  near 
the  ends  ;  striae  very  fine,  53  to  60 
in  '001".  =Pleurosig ma  cotnpactum,  MJ. 
V.  p.  12,  pi.  3.  f.  9  J  Pleurosigtna  rectum, 
Donkin,  TM.  vi.  p.  23,  pi.  3.  f.  6 ;  Am- 
phiprora Ralfsii,  Amott,  MJ.  vi.  p.  91. 
Britain.  -0045"  to  -005".  According  to 
Dr.  Donkin,  the  striae  are  longitudinal 
and  transverse  ;  colour  very  pale. 

D.    minuta   (Donkin).  —  Short,  very 


convex,  linear-oblong,  subacute,  sigmoid 
from  the  sloping  of  one  margin  near  each 
end  in  contrary  directions ;  median  line 
much  flexed  ;  striae  very  fine,  transverse 
ones  distinct,  about  55  in  -001",  longi- 
tudinal ones  obscure.  =Pleu7'osipna  mi- 
nutum,  Donkin,  /.  c.  p.  24,  pi.  3.  f.  8. 
England.  -0025" ;  colour,  very  pale 
brown.  D.  minuta  seems  to  differ  from 
D.  compacta,  to  which  Professor  Arnott 
would  unite  it,  chiefly  in  its  smaller  size. 

D.  angusta  (Donkin).  —  Very  con- 
vex, linear,  with  acute,  slightly  apicu- 
lated  apices ;  median  line  strongly  sig- 
moid, marginal,  except  a  central  diagonal 
portion  -,  striae  obscure,  longitudinal.  = 
Pleurosigma  anqustum,  Donkin,  I.  c.  p.  24, 
pL  3.  f.  9.  England.  -005"  to  -0055"; 
colour  dull  piu'ple.  Another  form  closely 
allied  to  D.  compacta. 

D.  reticulata  (Norman,  3//S'.). — Linear- 
lanceolate,  with  rather  obtuse  apices ; 
median  line  strongly  diagonal  at  the 
centre,  then  marginal  and  slightly  pro- 
jecting; striae  oblique,  distinct,  22  in 
•001".  Stomach  of  Ascidians,  Shark's 
Bay,  Australia.  Collected  by  Dr.  Mac- 
donald.  Colour  pm-plish  brown;  front 
view  oblong,  with  truncate  ends  and  con- 
stricted middle.  For  the  description  of 
this  species  we  are  indebted  to  George 
Norman,  Esq. 


Genus  AMPHIPROEA  (Ehr.)  (Entomoneis,  Elir.). — Frustules  free,  simple, 
in  front  view  constricted  at  the  middle ;  valves  convex,  with  a  longitudinal 
wing,  and  central  and  terminal  nodules  ;  striae,  when  present,  transverse. 
Marine.  Amphiprora  is  distiQguished  by  its  lateral  wings,  which  are  con- 
stricted at  the  middle,  so  that  the  frustule  in  front  view,  when  not  twisted 
(which,  however,  frequently  occurs),  is  more  or  less  panduriform,  with  trun- 
cate or  broadly -rounded  ends.  The  late  Professor  Smith  stated  that  the 
peculiar  frustules  of  this  genus  could  not  be  confounded  with  any  others, 
save  those  of  a  few  species  of  Nitzschia.  Erom  the  recent  discoveries  of 
Dr.  Donkin,  Amphiprora  is  found  far  more  closely  allied  to  Pleurosigma 
and  Donkinia.  Erom  these  genera  it  diff'ers  by  its  alate  valves,  and  by 
having  transverse  striae  only.  According,  ho\v^ever,  to  the  late  Professor 
Gregory  and  Dr.  Donkin,  the  valves  of  Amphiprora  are  furnished,  in  addition 
to  the  median  crest,  with  lateral  ones  also,  similar  to  those  of  SurireUa ;  and 
certainly  the  frustules  in  the  front  view  most  frequently  exhibit  a  longitu- 
dinal line  on  each  side  between  the  margin  and  the  central  portion — an 
appearance  not  unlikely  to  depend  on  such  a  formation,  particularly  in  A. 
ornatci  and  A.  p)aludosa,  in  which  these  lines  are  undulated.  An  end  view 
is  required  to  ascertain  whether  this  be  really  the  case,  since  the  same 
appearance  would  result  from  a  depression  along  the  sides  of  the  median 
crest,  and  even  the  undulations  may  be  produced  by  transverse  ridges. 


Amphiprora  alata(E.,'K.'). — Very  hya- 
line, generally  twisted ;  front  viev/  broad- 
ly winged,  strongly  constricted ;  wing  con- 


tinued round  the  ends ;  lateral  \-iew  with 
apiculate  ends  and  a  double  line  of  puncta 
accompanjdng   the    keel;    striae   42   in 


92^ 


SYSTEMATIC  HISTOEY  OF  THE  INFUSORIA. 


•001".  KB.  p.  107 ;  SD.  i.  p.  44,  pi.  15. 
f.  124.  =  Navicula  and  Entomoneis  alata, 
EB.  1845^  p.  154.  Common,  especially 
in  salt-water  marshes,  (xiii.  5  to  7.) 
1-570"  to  1-430"  5  central  portion  with 
longitudinal  lines. 

A.  Kdtzingii  (Breb.). —  Very  hyaline ; 
front  view  slightly  constricted,  longi- 
tudinally lined,  with  rounded  apices. 
KA.  p.  93.     France. 

A.  constricta  (E.).  —  Very  hyaline ; 
front  view  oblong,  sinuato-constricted, 
with  rounded  ends ;  lateral  view  narrow, 
with  straight  median  line,  and  transverse 
stauros-likeband.  EA.  p.  122, pi.  2. 6.  f.  28 ; 
SD.i.p.44,pl.  15.  f  126.  Europe,  America. 
(xii.  1.)     Stride  very  faint,  68  in  -001". 

A.  duplex  (Donkin). — Broad,  panduri- 
form,  with  truncate  ends  and  rounded 
angles;  lateral  view  narrow,  not  stri- 
ated ;  keel  strongly  sigmoid,  unaccom- 
panied by  puncta.  TM.  vi.  p.  165,  pi.  3. 
f.  13.  England.  Resembles  A.  alata  in 
the  broad,  deeply-constricted  front  view 
with  conspicuous  alee,  but  differs  from  it 
in  the  absence  of  striae  and  puncta,  and 
in  the  narrow-linear  lateral  view. 

A.plicata  (Greg.). — Front  view  deeply 
constricted,  with  broadly  roimded  ends  ; 
each  valve  with  a  plate  extending  from 
its  inner  margin  to  the  nodule,  fm^nished 
like  the  wings  with  about  50  fine  trans- 
verse strise  in  -001"  ;  central  portion 
with  faint  vertical  lines  or  folds.  GDC. 
p.  33,  pi.  4.  f.  57.  Scotland.  Approaches 
nearest  to  A.  alata,  but  differs  from  it  in 
the  folds  of  the  middle  space,  and  in  the 
presence  of  lateral  plates.  Judging  from 
the  figure  quoted,  the  longitudinal  lines 
are  similar  to  those  present  in  A.  alata 
and  other  species,  and  we  doubt  the 
distinction  of  the  lateral  plates. 

A.  pulclira  (Bailey).  —  Large ;  front 
view  deeply  constricted,  with  rounded 
ends,  distinctly  striated,  punctate  near 
the  margin.^  BC.  ii.  p.  38,  pi.  2.  f  16 
&  18.  Florida.  Often  twisted ;  central 
portion  narrow,  sigmoid,  with  a  few  fine 
longitudinal  lines. 

A.  quadrifasciata  (Bailey).  —  Small; 
front  view  moderately  constricted,  with 
truncate  or  slightly  rounded  ends ;  valves 
striated,  lanceolate,  with  produced  ros- 
tellate  apices.  BC.  ii.  p.  38,  pi.  2.  £  2-4. 
United  States.  When  living,  the  colour- 
ing matter  forms  four  yellowish  trans- 
verse bands ;  not  contorted. 

A.  vitrea  (S.).  —  Straight ;  front  view 
oblong,  with  rounded  ends  and  slight 
constriction  ;  lateral  \Tiew  lanceolate  ; 
striaj  52  in  -001".  SD.  i.  p.  44,  pi.  31. 
f.  270.     Britain. 


^  A.  elegajis  (S.). — Straight ;  front  view 
linear-oblong,  with  broadly  rounded  ends 
and  very  slight  notch-like  constriction ; 
lateral  view  lanceolate  ;  striae  40  in 
•001".  SD.  ii.  p.  90. ;  GDC.  p.  33,  pi.  4. 
f.  58.  Britain.  '^Distinguished  from  ^. 
vitrea  by  its  longer  and  comparatively 
more  lanceolate  and  slender  frustule, 
and  closer  striae"  (S.).  Professor  Ai-nott 
would  unite  this  with  A.  vitrea. 

A.  ohtusa  (Greg.). — Front  view  linear- 
oblong,  with  slightly  sinuated  sides  and 
rounded  ends  :  striae  veiy  line.  GDC. 
p.  34,  pi.  4.  l  60.  Scotland.  Alee  of 
nearly  uniform  breadth. 

A.  minor  (Greg.). — Front  view  oblong, 
with  slightly  sinuated  sides  and  rounded 
ends ;  striae  rather  coarse ;  central  smooth 
portion  lanceolate.  TM.  v.  p.  75,  pi.  1. 
f.  38.     Scotland. 

A.  pusilla  (Greg.).  —  Front  view  qua- 
drangular ;  alae  slightly  constricted,  the 
constriction  apparently  overlapped  by 
the  convexity  of  the  valve ;  lateral  view 
acutelv  lanceolate ;  striae  fine,  about  60 
in  -OOi".  GDC.  p.  33,  pi.  4.  f.  56.  Scot- 
land. 

A.  lepidoptera  (Greg.).  —  Elongated ; 
front  view  linear,  with  broadly  rounded 
ends  ;  the  notch-like  constriction  of  the 
alas  apparently  overlapped  by  the  con- 
vexity of  the  valve ;  lateral  view  lan- 
ceolate, apicidate ;  striae  fine,  about  48 
in  -001" ;  GDC.  p.  33,  pi.  4.  f.  69.  Scot- 
land. The  alae  are  carried  round  the 
ends,  and  in  the  lateral  \dew  appear  like 
an  apiculus. 

A.  maxima  (Greg.). — Front  view  very 
broad,  panduriform,  with  rounded  ends, 
the  notch-like  constriction  overlapped 
by  the  convexity  of  the  valve ;  striae 
distinct,  about  36  in  -001" ;  lateral  view 
acutely  lanceolate.  GDC.  p.  35,  pi.  4. 
f.  61.     Scotland. 

A.  complexa  (Greg.).  —  Front  view 
broadly  pandimform,  with  broadly  romid- 
ed  ends;  alae  with  marginal  pimcta ;  striae 
delicate,  about  45  in  -001"  ;  central  por- 
tion oblong,  with  concentric  longitudinal 
lines.  GDC.  p.  36,  pi.  4.  f  62.  Scot- 
land. 

A.paludosa  (S.). — T\^dsted;  front  view 
dilated,  broadly  winged,  deeplj-  con- 
stricted, with  rounded  or  truncate  ends, 
and  a  waved  longitudinal  line  on  each 
side  between  the  margin  and  central 
portion ;  sti-ic^  60  in  -001"  SD.  i.  p.  44, 
pi.  31.  f  269.  Britain.  Fresh  or  slightly 
brackish  water,  according  to  Smith; 
marine,  according  to  Professor  Arnott. 

A.  ornata  (Bailey). — Small;  front  view 
deeply   constricted,   with   truncated    or 


OF  THE  N-AYICULE.E. 


923 


roiinded  ends,  and  a  longitudinal  row  of 
undulations  on  each  side.  BC.  ii.  p.  38, 
pi.  2.  f.  15  &  23.  America.  Often 
twisted.  "  The  ruffle-like  rows  of  pin- 
nules distinguish  this  species  from  all 
others"  (Bailey). 

Doubtful  Species. 

A.  recta  (Greg.).  —  Front  ^dew  qua- 
drangular, with  rounded  angles  and  very 
slightly  constricted  sides ;  striae  fine  but 
distinct.  TM.  v.  p.  67,  pi.  1.  f.  40.  Scot- 


land. The  figure  presents  no  appearance 
of  alae,  but  only  convex  lateral  valves, 
such  as  are  seen  in  several  species  of 
Navicula. 

A.  navicularis  (E.).  —  Oblong,  with 
obtuse  ends  and  radiant  transverse  stride  ; 
front  view  quadrangular,  with  two 
pimcta  at  each  end.  EA.  p.  122  ;  EM. 
several  figures.  Fresh  water.  America. 
Apparently  a  Na\'icula  with  the  ter- 
minal puncta  of  the  front  view  less  mar- 
ginal than  usual. 


Genus  DIADESMIS  (Kiitz.).— Frustules  navicular,  united  into  a  filament; 
valves  with  central  and  terminal  nodules.  Habit  of  Fragilaria,  but  the  valves 
furnished  with  median  line  and  central  nodule.  Diadesmis  differs  from 
Sphenosira  only  in  having  the  lateral  siurfaces  with  similar  ends. 


*  Freshwater  or  Fossil. 

Diadesmis  confervacea  (K.). — Breadth 
of  articulations  twice  the  length ;  valves 
minute,  smooth,  with  acute,  acuminate 
ends.  KB.  p.  109,  pi.  30.  f.  8.  Trinidad. 
(XIV.  32,  33.)     1-960". 

D.  Icevis  (E.,  K.).  —Smooth;  breadth 
of  articulations  three  to  four  times  the 
length.  KB.  p.  109,  pi.  29.  f.  69.  =  T«Je/- 
laria  Icevis,  EA.  pi.  1.  2.  f.  17.  Chili, 
(xii.  40.) 

D.  sculpta  (E.,  K.).  —  Articulations 
with  striated  margins  ;  valves  linear- 
oblong,  with  roimded  ends  and  a  narrow 
sti-iated  border.  IvB.  p.  109,  pi.  29.  f.  26. 
=  TaheUaria  sculpta,  EA.  pi.  1.  2.  f.  6. 
Chili.     Resembles  Navicula  horealis,  E. 

D.  ?  Bacillum  (E.,  K.). — Articulations 
striated,  linear-oblong,  with  rounded 
ends,  and  a  large,  oblong,  longitudinal 
median  nodule.  KB.  p.  109.  =  Navicula 
Bacillum,  E.     Fossil.     Greece. 

D.  Navicula  (E.). — Frustules  oblong, 
smooth,  four   or  five  times   as  long   as 


broad,  with  a  smooth  median  stiicture. 
=  Fragilaria  ?  Navicula,  EA.  p.  127, 
pi.  1.  3.  f.  8.  Peru.  We  place  this  form 
in  Diadesmis  because  the  frustules,  in 
the  front  view,  have  a  minute  punctum 
at  the  middle  of  each  lateral  margin, — 
an  appearance  which  usually  indicates 
the  presence  of  central  nodules. 

D.  Gallica  (S.).  —  Filaments  straight 
or  curved ;  valves  linear-elliptical,  with 
about  45  obscure  striae  in  -001".  Sm. 
ANH.  Jan.  1857,  p.  11,  pi.  11.  f.  16. 
Havre. 

D.  peregrina  (S.). — Victoria  tank,  Glas- 
gow.    This  species  is  unknown  to  us. 

2*  Marine. 
_  D.  WilUamsoni  (S.,  Greg.),  —  Front 
\aew  linear,  with  central  and  terminal 
dilatations;  valves  linear,  with  attenuated 
ends  and  16  to  18  dotted  sti'iae  in  -001. 
GDC.  p.  m,  pi.  2.  f.  40.  =  Himcmtidium 
Williamsoni,  SBD.  ii.  p.  14,  pi.  33.  f.  287. 
Marine.     Scotland. 


Genus  STIGMAPHORA  (WaUich).  —  Frustules  free,  naviculoid ;  valves 
lanceolate,  loculate ;  loculi  with  central  and  marginal  puncta.  Marine. 
Frustules  very  hyaline,  with  two  minute  cells  at  the  midcHe  of  each  margin 
in  both  views ;  valves  with  median  line. 


Stigmaphora  rostrata  (Wallich).  — 
Valves  rostrate  ;  beaks  with  a  median 
row  of  puncta.  TM.  viii.  p.  43,  pi.  2. 
f.  5,  6.    (Yiu.  48.)     India. 


S.  lanceolata  (Wallich).  —  Valves 
acutely  lanceolate,  without  median  rows 
of  puncta.  TM.  viii.  p.  43,  pi.  2.  f.  7,  8. 
India. 


924 


SYSTEMATIC  HISTOET  OF  THE  rNTTJSOEIA. 


2  *  Frustules  naviculold,  envelojped  in  gelatine  or  enclosed  in  a  definite 
tubular  or  gelatinous  frond. 

Subfamily  SCHIZONEME^  or  LACERNAT^. 

This  group  is  remarkable  for  the  great  external  resemblance  some  of  its 
species  have  to  acknowledged  Algae,  widely  as  they  differ  in  internal  structure. 

Genus  ERUSTULIA  (Ag.). — Erustules  bacillar  or  navicular,  immersed  in 
an  amorphous  gelatinous  substance.  For  the  present  we  retain  this  genus 
in  the  Schizonemese,  but  believe  that,  in  most  if  not  all  the  species,  the  frus- 
tules  are  more  like  a  Synedra  than  a  Navicula,  and  want  the  central  nodule 
of  the  latter. 


t  StriaB  evident. 

Frustulia  salina  (E.). — Very  narrow 
linear,  transversely  striated ;  in  front  view 
with  rounded  ends,  in  lateral  view  sud- 
denly acute.  E  Inf.  p.  232.  Saline 
springs,  Germany. 

2 1  Striae  wanting,  or  very  indistinct. 

F.  Kiitzingiaiia  (Rab.). — Smooth,  lan- 
ceolate, with  truncate  apices.  Rab  D, 
p.  35,  pi.  8.  f.  3.  =  Synedra  mucicola,  KB. 
p.  68,  pi.  14.  f.  5.  On  stones  in  a  rivulet 
near  Nordhausen. 

F.  minuta  (Rab.).  —  Minute,  linear, 
smooth,  in  front  view  with  truncate 
apices ;  valves  with  acutely  cuneate  ends. 
Rab  D.  p.  35.  t.  8.  f.  4.  =  Synedra  Frus- 
tulum,  KB.  pi.  30.  f  77.  Fresh  water. 
Germany  and  Italy.  It  forms  an  olive- 
brown  gelatinous  mass  on  stones,  and 
becomes  green  in  drying. 

F.  torfacea  (Braun).  — Rhomboid-lan- 
ceolate, with  obtuse  apices,  a  stout  me- 
dian rib,  and  small  central  nodule.  RabD. 
p.  50,  t.  7.  £  2.  Germany.  It  forms  dirty- 
yellow,  rather  firm,  smooth  or  rugged 
gelatinous  masses  about  plants  ui  bogs. 
An  authentic  specimen  from  Professor 


Braun  appears  to  us  identical  with  Na- 
victda  rhotnboides. 

F.  Saxonica  (Rab.).  —  Slenderer  than 
F.  torfacea,  ynih.  valves  more  acute ; 
front  view  linear,  with  broadly  rounded 
ends.  Rab  D.  p.  50,  t.  7.  f  1.  Saxony. 
Forms  dirty-olive-brown  tremulous  j  elly- 
like  masses  in  little  cavities  of  damp 
rocks. 

F.  Hcsckeriana  (Rah.). — Valves  spin- 
dle-shaped, with  acute,  pointed  endsj 
front  view  narrow-lanceolate,  with  ob- 
tuse apices.  Rab  D.  p.  50,  pi.  10.  f  14. 
Germany.  Forms  dirty  gelatinous  masses 
on  moss  in  streams. 

F.  acicidaris  (E.).  —  Bacilla  slender, 
smooth,  with  acute  apices ;  valves  more 
acute,  like  a  fine  needle.  ERBA.  1853, 
p.  527.  Marine.  Kingston  Bay.  Frus- 
tules  like  those  of  Fragilaria  Rhahdo- 
soma,  but  free  and  heaped  together 
without  order. 

F.  hacillaris  (E.). — Bacilla  linear,  pin- 
nulate,  with  truncate  apices  in  the  front, 
and  rounded  in  the  lateral  view.  EB. 
1853.  Marine.  Kingston  Bay.  This 
species,  like  F.  acicidaris,  seems  included 
in  gelatine  dilated  like  an  idva,  which, 
when  dry,  appears  membranaceous.  In 
the  same  membrane  both  species  are  in- 
cluded, with  many  other  Diatomacese. 


Genus  MASTOGLOIA  (Thwaites). — Frustules  oblong,  naviculoid,  annulate, 
in  a  gelatinous  mammillate  cushion  or  frond ;  annuH  loculated ;  loculi  open- 
ing by  foramina  along  the  line  of  suture.  ^'  The  frustules  of  Mastogloia 
are  notably  distinct  from  those  of  the  other  genera  of  this  tribe,  having  the 
annulate  structure  of  Rhabdonema  with  the  canaliculi  of  Surirella."  ''  The 
canaliculi  are,  however,  formed  differently  from  those  of  Surirella,  not  being 
connected  with  the  valve,  but  with  the  annulus,  which  projects  as  a  septum 
into  the  body  of  the  frustule.  The  fmstule  itself  is  ordinarily  excentric  to  the 
mucus  developed  around  it,  and  sits  as  it  were  on  the  summit  of  a  little 
nipple-like  cushion  of  gelatine  "  (Smith). 


Mastogloia  Danseii  (Thwaites).  — 
Valves  elliptic-oblong,  with  8  to  20  lo- 
culi ;  strij©  42  in  -001".     SB.  ii.  p.  64, 


pi.  62.  £  388.  =  Dickieia  Banseii,  ANH. 

1848.  Brackish  water.  Britain.    (xv.30.) 

M.  lanceolata  (Thw.). — Valves  oblong- 


OF  THE  NAVICULE^. 


925 


lanceolate,  with  subacute  apices  and  8  to 
30  loculi ;  stride  42  in  -001".  SD.  ii.  p.  64, 
pi.  54.  f.  340.     Brackish  water.     Britain. 

M.  Smithii  (Thw.).  —  Valves  oblong- 
lanceolate,  with  produced,  obtuse  or 
capitate  apices,  and  6  to  24  loculi ;  striae 
42  in  -001".  SD.  ii.  p.  65,  pi.  54.  f.  341. 
Fresh  or  brackish  water.     Britain. 

M.  apiculata  (S.). — Valves  elliptic- 
lanceolate,  Avith  slightly  produced,  ob- 
tuse, conic  apices,  and  30  to  50  loculi ; 


striae  42  in  -001' 
f.  387.     Marine. 


.     SD.  u.  p. 
Britain. 


65,  pi.  62. 


M.  GrevUlii  (S.). — Valves  linear,  Tvdth 
obtuse,  cuneate  ends,  and  15  to  20  loculi ; 
striae  moniliform,  24  in  001.  SD.  ii. 
p.  65,  pi.  62.  f.  389.  Fresh  water.  Britain. 

M.  minuta  (Grev.).  — Valve  elliptic- 
lanceolate  or  elliptic-oval,  conspicuously 
apiculate ;  loculi  12  to  18 ;  striae  very  fine 
and  close.  Trinidad.  Grev.  MJ.  v.  p.  12, 
pi.  3.  f.  10.  It  is  a  species  evidently  aUied 
to  31.  apiculata,  but  differs  in  being 
scarcely  half  the  size,  and  essentially  in 
the  much  larger  loculi  j  it  is  also  much 
more  apiculate. 


Genus  PHL  YCT^:N'IA  (Kiitz.). — Frustules  navicular,  included  in  (globose) 
gelatinous  cells.     Maiine. 


Phlyct^nia  minuta  (K.). — Parasitic ; 
cells  hyaline,  achromatic,  solitary,  scat- 
tered, or  binately  approximate  and  aggre- 
gated; included  naviculae  few,  binately 
or  quatemately  conjoined,  smooth  ; 
front  view  linear,  with  truncate  apices  ; 
valves  broadly  lanceolate,  with  acumi- 
nated ends.    KSA.  p.  96.     Adriatic  Sea. 

P.  maritima    (E.,  K.).  —  Naviculae 


smooth  (?),  linear,  with  rounded  ends 
contained  in  distinct,  but  contiguous, 
gelatinous  cells.  KA.  p.  96.  =  Fnfsfulia 
maritima,  E  Inf.  p.  232.  Near  Gothen- 
burg. 1-1200"  to  1-1150".  This  species 
occurs  as  a  brownish  jeUy-like  mass  on 
stones.  In  the  gelatinous  cells  Ehr- 
enberg  obseiTed  from  one  to  twenty 
frustules. 


Genus  DICKIEIA  (Berkeley). — Frond  subgelatinous,  plane,  attenuated  to- 
wards the  base,  containing  scattered,  navicular,  imperfectly  silicious  frustules. 
Marine.     Dickieia  is  distinguished  by  its  plane  frond  and  scattered  frustules. 

DiCKiEiA  ulvoides  (Berk.).  —  Frond 
undivided ;  valves  elliptical.  ANH.  xiv. 
pi.  9;  SBD.  ii.  p.  66,  pi.  54.  f.  342. 
Britain,  (xv.  31.)  Frond  linear  or 
obovate-stipitate ;   striae  obscure,  36  in 


'001" ;  nodule  transverse,  Sm. 


D.  pinnata  (Ralfs).  —  Frond  divided ; 
valves  elliptic-lanceolate.  ANH.  2nd 
ser.  viii.  pi.  5._  f  6;  SBD.  ii.  p.  66,  pi.  54. 
f  343.  Britain.  Autumn.  Divisions  of 
frond  subpinnate;  striae  obscure,  40  in 
■001" ;  nodule  pimctifomi,  Sm. 


Genus  RHAPHIDOGLCEA  (Kiitz.).— Frond  globose,  gelatinous,  tender, 
filled  with  fusiform  bundles  of  naviculae  disposed  in  radiating  threads. 
Marine.  ''  The  principal  character  of  this  genus  is  taken  from  the  amor- 
phous disposition  of  the  gelatinous  substance  in  which  the  frustules  are 
immersed.  The  frustules  are  mixed  together  in  a  disorderly  manner  in 
Berkeleya,  whilst  in  Ehaphidogloea  they  are  arranged  in  fusiform  fascise, 
confluent  by  the  pointed  extremities"  (Meneg.).  We  think  this  genus 
might,  without  inconvenience,  be  united  with  Berkeleya. 

Rhaphidoglcea  medusina  (K.).  — 
Minute ;  fascicles  lanceolate-acuminate, 
in  irregular,  reticulately-branched,  con- 


tinuous, radiating  threads  ;  naviculae 
lanceolate.  KB.  p.  110,  pi.  22.  f.  7.  Me- 
diterranean Sea.    1-600". 

it.  manipidata  (K.).  —  Globose,  pisi- 
form; rays  of  fascicles  reticulated,  not 
interrupted;  naidculae  linear-lanceolate, 
obtuse.  KB.  p.  110,  pi.  22.  £  5.  Eui-ope. 
1-700"  to  1-290". 

K.  interrupta  (K.).  —  Pisiform,  with 
slender  rays  of  fascicles,  interrupted  in 
a  joint-like  manner,  with  gradually  ta- 
pering branches;  naAacidae  linear,  slightly 


attenuated  at  the  truncate  apices.  KB. 
p.  110,  pi.  22.  f  6.  Adriatic  Sea.  1-300". 
R.  micans  (Lyngb.,  K.). — Subglobose  ; 
rays  of  the  larger  fascicles  irregular, 
obsolete  ;  navicidae  linear  -  lanceolate, 
subulate,  rather  acute,  elongated.  KB. 
p.  110,  pi.  22.  f.  8.  =  Schizonema  micans, 
AD.  p.  17 ;  Naimema  micans,  E  Inf. ; 
Frustulia  costata,  LobarzeuskyinLinnaea, 
1840,  pi.  5.  f.  1.  Europe.  "  Mr.  Tuffeii 
West  informs  us  that,  from  careful  obser- 
vation of  li\aug  specimens,  he  is  satisfied 
that  this  species  is  identical  with  Am- 
pliipleura  pellucida,  in  which  opinion  the 
late  Prof  Smith  fidly  concurred. 


926 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


Genus  BERKELEYA  (Grev.).  —  Frustules  na\iciiloid,  linear-lanceolate, 
included  within  tubular  submembranaceous  filaments,  which  are  free  at 
their  extremities,  but  immersed  below  in  a  more  or  less  definite  tubercle. 
Marine.  Berkeley  a  differs  from  Schizonema  in  having  the  base  of  the  fila- 
ments immersed  in  an  orbicular  gelatinous  tubercle.  This  tubercle  is  at  first 
firm  and  definite,  but  finally,  especially  when  growing  on  rocks,  becomes 
enlarged,  soft,  and  often  somewhat  indefinite. 


Berkeleya  fragilis  (Grev.).  —  Fila- 
ments subsimple,  minute  ;  frustides 
crowded,  slender,  lanceolate  or  linear- 
lanceolate,  with  the  striae  obsolete  or 
wanting.  GBF.  p.  416 ;  SD.  ii.  p.  67, 
pi.  54.  £  344.  On  Zostera,  Algae,  and 
rocks.  Em-ope.  The  gelatinous  tubercle 
diu'ing  growth  becomes  attenuated  and 
more  dilFused,  and  sometimes  forms  an 


indefinite  slimy  covering  about  the  base 
of  the  filaments.  In  a  dried  state  this 
species  acquires  a  metallic  lustre. 

B.  Adriatica  (K.). — Filaments  branch- 
ed ;  branches  distinctly  subdi-sdded ;  frus- 
tides narrowly  linear-lanceolate,  rather 
obtuse.  I^.  p.  109,  pi.  22.  f  4.  Adriatic 
Sea.  (xiv.  34, 35.)  1-300".  Scarcely 
distinct  from  B.  fragilis. 


Genus  COLLETONEMA  (Breb.). — Frustules  naviculoid,  arranged  in  series 
within  a  tender,  simple  or  divided,  filiform  or  globose  frond.  Aquatic. 
According  to  Professor  Smith,  "  the  freshwater  habitat  and  slightly  divided 
frond  distinguish  the  present  genus  from  Schizonema;  and  [he  adds]  the 
frustules  are  also  more  firmly  sihceous  than  those  of  that  genus,  and  the 
character  of  the  valve  can  usually  be  well  seen  after  maceration  in  acid." 
Professor  Kiitzing  describes  CoUetonema  as  having  a  filiform  frond  composed 
of  series  of  naviculae  held  together  and  enveloped  by  an  amorphous  gelatinous 
mucus,  without  an  exterior  gelatinous  tube.  We  doubt  if  any  of  the  above 
characters  sufficiently  distinguish  CoUetonema  from  the  allied  genera,  because 
they  are  either  inadmissible  in  generic  definitions,  uncertain,  or  not  pecuhar 
to  the  genus.  The  absence  of  an  external  tube,  if  constant,  would  be  of 
generic  importance  ;  but  we  sometimes  find  the  frustule  contained  within  an 
evident  (although  tender  and  evanescent)  tube,  whilst  in  Micromega,  on  the 
other  hand,  the  presence  of  an  external  tube  is  sometimes  doubtful.  The 
fronds  are  exceedingly  tbin  and  tender,  readily  permitting  the  escape  of  their 
frustules,  which  may  then  be  mistaken  for  species  belonging  to  other  genera ; 
thus  Professor  Smith  remarks  that  it  is  possible  that  Pinnularia  radiosa  may 
be  merely  the  free  state  of  CoUetonema  neglectum,  and  Navicida  crassinervia 
the  same  condition  of  C.  vulgare. 


CoLLETONEMA  exwiium  (Thw.,  K.). 
—  Frond  filiform ;  frustide  in  lateral 
view  sigmoid,  striated.  KA.  p.  891 ; 
SD.  ii.  p.  69,  pi.  56.  £  350.  =  Schizonema 
eximiimi,  ANH.  1848 ;  Gloionema  sig- 
moides,  EB.  1845 ;  Encgonema  sigmoides, 
KA.  p.  62.  ?  Britain,  Demerara  ?  Valves 
linear,  sigmoid  from  the  ends  sloping  in 
opposite  directions ;  striae  56  in  -001". 
(VIII.  43.) 

C.  viridulum  (Breb.). — Frond  filiform ; 
naviculae  spirally  and  densely  arranged ; 
valves  lanceolate,  rather  obtuse,  smooth ; 
front  view  linear-oblong,  slightly  and 
gi'adually  attenuated  towards  the  trun- 
cate apices.     KA.  p.  105.     France. 

C.  lacustre  (Ag.,  K.). — Frond  filiform, 
simple  or  subramose,  finer  than  a  hair, 
enclosed  in  an  imperceptible  membrane ; 
naviculae  elliptic  or  parallelogramic,  in 
a  single  or  double  series.     KSA.  p.  105. 


=  Schizonema  lacustre^  Ag  CD.  p.  18. 
Sweden.  Tufts  erect,  brownish  yellow;  in 
size  and  habit  like  Sphacelaria  cirrosa. 

C.  vidgare  (Thw.),  —  Frond  filiform, 
simple  or  divided,  gradually  taperiug, 
containing  one  or  two  regular  rows  of 
frustules ;  valves  oblong-lanceolate,  with 
slightly  contracted,  obtuse  ends.  SD.  ii. 
p,  70,  pi.  56.  f.  351.  =  Schizonetna  vidgare, 
ANH.  1848.  England  and  France.  Less 
common,  according  to  Professor  Smith, 
than  the  next  species.     Striae  72  in  -001". 

C.  neglectum  (Thw.). — Frond  slightly 
divided,  obtuse,  containing  numerous 
and  closely  packed  frustules ;  valves  lan- 
ceolate, with  obtuse  ends.  SBD.  ii. 
p.  70,  pi.  56.  f.  352.  =  Schizonema  neg- 
lectum, ANH.  1848.     England. 

C.  subcohcsrens  (Thw.). — Frond  glo- 
bose, gelatinous,  pervaded  by  hregular 
rows  of  frustules;  valves  oblono-,  with 


OF  THE  KAYICTJLE^.  92* 


rounded  apices.  SD.  ii.  p.  70,  pi.  56. 
f.  353.  Dorset.  Strict  28  in  -001".  In 
the  character  of  its  frond  this  species 
somewhat  agrees  with  Rhaphidogioea  j 
but  the  frustules  are  arranged  in  series, 
not  in  fascicles,  as  in  that  genus. 

Doubtful  Species, 

C.  ?  ampJiioxys  (E.,  K.). — Known  only 
from  fragments.      Naviculae    parallelo- 


gramic,  smooth;  valves  acutely  lanceo- 
late. KSA.  p.  105.  =  Naunema  am- 
phioxys,  EA.  pi.  3.  2.  f.  5.  Mexico. 
(xii.  55-57.) 

C.  ?  Americaman  (E.,  K.). — Naviculae 
striated,  large,  linear,  with  subacute 
apices,  densely  arranged  wdthin  branched 
tubes.  IvA.  p.  105.  =  Naunema  Ameri- 
ca mon,  EB.  1845,  p.  79.  River  Hudson. 
Strife  18  in  1-1200". 


Genus  SCHIZONEMA  (Ag,,  Kiitz.)  (Monema,  Grev. ;  Monnema,  Meneg. ; 
Naunema,  Eh7\), — Erustiiles  naviculoid,  arranged  confusedly  or  in  a  single 
file,  within  a  capiUary,  submembranaceous,  single-tubed,  more  or  less  branched 
frond,  of  nearly  equal  diameter  throughout.  This  genus,  constituted  by 
Agardh,  has  been  repeatedly  divided  and  reunited,  and  the  generic  names 
altered  and  transposed  in  an  arbitrary  manner  without  regard  to  priority. 
Dr.  GreviUe  founded  Monema  for  the  species  with  single  tubes,  retaining 
those  with  compound  fronds  in  Schizonema.  This  division  seems  judicious, 
and  indeed  has  been  adopted  by  nearly  every  succeeding  writer,  although 
Greville's  names  have  been  disused  or  differently  applied.  Agardh  recognized 
the  distinctions,  but  retained  Schizonema  for  the  species  with  a  frond  of 
simple  structiuT,  and  founded  Micromega  for  the  species  having  a  compound 
structui-e.  As  this  arrangement  has  been  foUow^ed  by  Kiitzing,  and  acquiesced 
in  by  Greville,  we  use  it  here.  There  is  the  greatest  difference,  how^ever,  in 
the  distribution  of  the  species,  even  amongst  those  who  admit  both  genera. 
"  This  discordance  of  opinion,"  observes  Meneghiui,  "  as  to  the  aiTangement 
of  some  species  in  one  or  other  of  the  two  genera,  which,  independently  of 
their  names,  appear  so  distinct  and  so  clearly  defined,  arises  from  the  great 
difficulty  of  discerning  the  parallel  tubes  including  the  particular  series  of 
naviculae.  In  some  species  the  wall  of  the  external  tube  is  clearly  distinct, 
and  the  naviculae  are  confused  within ;  but  in  some  others  it  seems  as  if, 
instead  of  a  tube,  there  were  a  mucous  mass  in  which  the  naviculae  are  im- 
mersed." Professor  Smith  considered  that  "  this  great  diversity  of  opinion 
owes  its  origin  to  the  variableness  and  inconstancy  of  the  characters  adopted 
by  the  writers  who  arranged  the  species  under  two  genera.  The  presence  of 
only  one  or  of  many  files  of  frustules  is  certainly,  to  some  extent,  dependent 
upon  the  stage  of  growth  of  the  specimen  examined ;  and  the  appearance  of 
secondary  tubes  within  the  general  mucus-envelope  is  more  or  less  apparent 
in  different  portions  of  the  same  frond,  or  according  as  it  is  examined  in  the 
fresh  or  dry  state.  A  very  extensive  comparison  of  specimens  leads  me  to 
beheve  that  in  every  case  where  the  development  of  the  frond  is  much 
advanced,  as  in  the  older  or  basal  portions,  numerous  files  of  frustules  may 
be  observed."  For  these  reasons  Professor  Smith  united  the  genera  and 
divided  Schizonema  into  two  sections,  "  the  first  having  frustules  fir^mly 
sHiceous,  and  fronds,  in  consequence,  somewhat  setaceous  and  robust ;  and  the 
second  including  those  species  whose  frustules  are  flaccid  and  dehcate  in 
character."  As  we  consider  the  diagnostic  differences  sufficient,  we  have 
retained,  with  slight  alteration,  the  arrangement  of  the  species  in  these 
genera  given  by  Meneghini  in  his  memoir  upon  the  Diatomacea?.  The  frond 
in  Schizonema  is  generally  densely  tufted  and  more  sparingly  branched  than 
in  Micromega.  It  is  always  single-tubed,  and  usually  very  slender,  with 
even,  parallel  margins.  The  ends  of  the  filaments,  which  in  the  early  state 
are  often  empty,  iinaUy  become  ruptured  and  permit  the  escape  of  the 
naviculae.     In  a  recent  state  these  characters  will  generally  suffice  to  deter- 


928 


STSTE3IAT1C  HISTOET  OF  THE  U^FUSOEIA. 


mine  the  genus,  even  before  minute  microscopic  examination.  We  place 
more  reliance  upon  colour  in  the  discrimination  of  species  than  some  writers 
allow.  The  colour  for  the  most  part  depends  upon  the  contents  of  the  frus- 
tules,  and,  according  to  our  experience,  is  subject  to  little  variation,  except 
in  old  specimens  rendered  unfit  for  comparison  by  the  escape  of  the  naviculae. 

pi.  69.  f.  367.  On  mud  in  sheltered 
places.  Tufts  of  a  duller  brown  than 
S.  Dillwynii,  gradually  turning  in  fresh 
water  to  a  dark  olive-green,  not  quickly 
becoming  offensive.  Frustules  in  form 
and  size  similar  to  those  of  *S'.  rutilans. 

S.  cluhium  (Harv.).  —  Eesembles  S. 
Dillwynii;  but  the  long  branches,  naked 
below,  are  furnished  towards  their  sum- 
mits wdth  numerous  cmied  ramuU.  Harv. 
Manual,  p.  212.  =  aS".  Dillwynii  /3,  KA. 
p.  101.  Kocks,  &c.  Tufts  unequal- 
topped  ;  apices  of  ramuli  acute ;  naviculse 
ver}^  minute  and  densely  packed. 

S.  virescens  (Harv.).  —  Fronds  very 
slender,  densely  tufted,  tenacious,  very 
much  branched  from  the  base;  ramidi 
numerous,  curled,  upper  ones  longest, 
swelling  towards  the  tips,  which  are 
dark-coloured  and  end  in  a  sudden 
point ;  naviculse  minute.  Harv.  Manual, 
p.  212.  North  Devon.  Tufts  dense, 
brownish  olive,  not  much  altered  in 
drying.  Under  the  microscope  it  has 
much  the  appearance  of  S.  Dilhvynii; 
but  the  thickened,  dark-coloured  tips 
are  remarkable. 

S.  rutilans  (Trentepohl,  Ag.). — Densely 
tufted:  filaments  elongated,  subsimple, 
I  browTiish  and  empty  at  base,  hyaline 
and  filled  with  crowded  linear-oblong 
frustules  at  the  apex ;  when  drv,  shining 
and  reddish.  Ag  CD.  p.  18 ;  KB.  p.  112, 
pi.  23.  f.  6.  1,  2.  =  Monnema  rutilans, 
Meneg.  ^'  It  differs  from  S.  Dilhvynii  by 
its  more  varnish-like  lustre,  reddish 
colour  when  dry,  and  finer  and  more 
simple  filament"  (Ag.), 

S.    Hoffmannii    (Ag.).  —  Filaments 
tufted,  subsimple,  arachnoid,  when  dry 
shining  with  a  reddish  lustre ;  navicidas 
small,  smooth,  crowded ;  valves  lanceo- 
late, =  S.  rutilans,  var,  Hoffmatmi,  KB. 
pi.  23.  f.  10;  Monnema  Hoffnianni,  Meneg. 
Europe,  Aberdeen,    (x.  207.)    Professor 
i  Kiitzing  makes  this  form  a  variety  of 
I  S.  rutilans ;  but  Meneghini  observes  that 
i  they  differ  in  external  characters  and  in 
j  the  dimensions  and  shape  of  the  navi- 
cidfe.     1-1080"  to  1-960". 

S.  Balticum  (E.), — Navicidas  stiiated, 
slender,  linear-lanceolate,  in  front  view 
trmicate,  in  lateral  view  subacute,  dense, 
crowded  in  the  intricately  branched  fila- 
ments.   E  Inf.  p,  236,  pi.  20.  f.  \b.=S. 


*  Central  nodule  transversely  dilated. 

ScHizoNEMA  cruciyer  (S,). — Filaments 
much  di\dded  ;  naviculee  crowded  ; 
valves  lanceolate,  acute,  striated;  me- 
dian nodule  transversely  dilated  into  a 
stauros.  SD.  ii.  p.  74,"  pi.  66.  f.  354. 
Britain.     Striae  distinct,  40  in  -OOl". 

2  *  Central  nodule  punctiform,  sometimes 
obsolete. 

S.  GrevilUi  (Ag.).  —  Frond  membra- 
naceous, much  branched,  level-topped; 
naviculae    in    front  -view   subquadrate ; 
valves  oblong-lanceolate,  with  60  striae  j 
in  -001".     AgCD.  p.  19;  SD.  ii.  p.  77,  ] 
pi.  58.    f.  364.  =  3Ionnema     GrevilUi,  \ 
Meneg. ;   S.  quadripunctatum,  Harv.    On  j 
rocks  and  mud.     Fronds  densely  tufted, 
bro^vTi,  turning  to  a  dirty  verdigris-green  j 
when  dried,  and  adhering  imperfectly  to  : 
paper.    Naviculae  large,  crowded  at  base,  | 
m  a  single  file  near  the  extremities.     S.  1 
quadripunctatum  of  British  ^\Titers  is  an 
old  state,  and  tm-ns  of  a  rusty  colom-  in 
drying.     1-576". 

S.  crinoideum  (HaiT.).  —  Filaments 
very  slender,  achromatic,  sparingly 
branched,  densely  woven  into  a  pale- 
green  or  brownish  stratum ;  naviculae 
very  minute,  disposed  in  an  irregidar 
loose  series.  Harv.  Manual,  p.  214.  =*& 
tenellum,  KB.  p.  Ill,  pi.  23.  f.  8  ;  Mon- 
nema quadripunctatum,  Meneg.  Eiu'ope. 
Filaments  exceedingly  slender,  with  long, 
simple,  flexuose  branches.  Brown  when 
recent,  olive-green  and  glossy  when  dry, 
1-1386". 

S.  Dillwynii  (Ag.).  —  Frond  densely 
tufted,  rich  brown,  very  slender;  navi- 
culae minute ;  valves  lanceolate-acute, 
smooth,  SD,  ii.  p.  77,  pi.  58.  f  366,= 
Monema  Dillwynii,  GCF,  pi,  297.  Rocks, 
mud,  and  Algae.  Naviculae  imper- 
fectly silicious,  more  or  less  crowded, 
especially  near  the  extremities;  fronds 
turning  deep  green  on  immersion  in 
fresh  water,  and  quickly  acquiring  an 
offensive  smell;  generally  glossy  when 
dried.    1-1000". 

S.  imj^licatum  (Harv.),  — Frond  capil- 
lary, densely  tufted,  much  branched, 
curled,  and "  entangled  ;  naviculae  very 
minute,  irregularly  crowded ;  valves  lan- 
ceolate,  rather    obtuse.     SD.  ii.  p.  78, 


OF  THE  XAYICrLE^. 


929 


rutilans,  rar.  viride  ',  3Ionne7na  octo- 
carpoides,  Meueo-.  Europe,  England. 
1-1200". 

S.  Ehretihergii  (K.). — Frond  parasitic, 
lubricous,  tufted,  green,  branched; 
branches  crystal-hyaline,  soft,  obtuse  at 
the  apex ;  naviculae  (in  dried  specimens) 
inconspicuous,  tender,  arranged  in  obso- 
lete series,  oblong  in  one  view,  truncate 
in  the  other,  with  rounded  ends.  KB. 
p.  113,  pi.  23.  i.2.  =  Naunema  DiUwynii, 
E  Inf.  p.  235,  pi.  20.  f.  13.  Eui'ope. 
1-1320".  ^ 

S.  spadiceum  (Grey.). — Filaments  ca- 
pillary, tufted,  much  branched,  of  a  red- 
dish oliye-green  colour;  ramuli  much 
diyaricated,  idtimate  ones  patent;  nayi- 
culse  linear-oblong,  elongated.  Grey,  in 
Hooker's  Br.  Fl.  p.  412.  Scotland. 
Fronds  often  with  a  faint  metallic  lustre 
when  dry.  Filaments  yeiy  slender,  and 
of  nearly  equal  thickness  throughout. 

S.  Adriaticmn  (Ag.). — Filaments  finer 
than  a  hair,  elongated,  subsimple,  when 
dried  of  an  opaque  oliye  green  ;  na\"iciilae 
narrow, lanceolate.  AgCD.  p.21.  Venice. 

S.  confertum  (S.).  —  Frond  filiform, 
sparingly  divided  throughout ;  nayiculae 
exceedingly  crowded ;  yalyes  shortl}^  lan- 
ceolate, acute,  with  indistinct,  marginal 
eti-iaj.  SD.  ii.  p.  75,  pi.  57.  f.  359.  Aber- 
deen.    -0008"  to  -0011". 

S.  lutescens  (K.). — Tufted,  when  dry 
of  a  reddish  colour,  glossy ;  filaments 
subsimple,  capillary,  coloured  and  empty 
at  base,  hyaline  and  filled  with  nayi- 
culfe  at  the  apex ;  nayiculse  oblong-lan- 
ceolate, obtuse.  KB.  p.  112.  Europe. 
1-1200". 

S.Jlavum  (K.). — Frond  tufted,  lubri- 
cous, yellow;  filaments  tenacious,  cry- 
stalline, achromatic,  straight,  fastigiate, 
branched;  branches  attenuated  at  the 
apex,  erect ;  nayiculee  scattered  or  inter- 
ruptedly aggTegate,  oblong  or  linear,  with 
obtuse  or  truncate  ends.  KSA.  p.  101. 
France.     Nayicidse  rather  broad. 

S.  hdeum  (K.). — Frond  tufted,  yeUow ; 
filaments  achromatic,  capillary,  subfra- 
gile,  nearly  equal  throughout ;  nayiculEe 
linear  or  acicular,  inconspicuous,  alter- 
nately loosely  and  densely  compacted. 
KA.  p.  102.   "^France.     1-1080". 


S.  soi'didum  (II.).  —  Fronds  minute, 
tufted,  parasitic,  dull  brownish-grey; 
filaments  subdichotomous,  achromatic, 
with  equal  branches;  nayiculae  slender, 
truncate ;  yalves  lanceolate-linear,  rather 
obtuse.  KB.  p.  113,  pi.  24.  f.  l.=iT/ow- 
nema  sordidum,  Meneg.  On  Zostera. 
Europe.    1-1440"  to  1-1200". 

S.  tenue  (Ag.). — Filaments  arachnoid, 
irregidarly  branched;  naviculse  elliptic, 
disposed  almost  in  a  single  series.  KB. 
p.  112,  pi.  23.  f.  2.  =  Monnema  tenue, 
Meneg.  Adriatic  Sea.  When  dried  it 
appears  as  a  sidphur-green  stain ;  fila- 
ments inconspicuous  from  their  tenuity, 
Ag.  Professor  Kiitzing  refers  Agardh's 
species  to  his  S,  mucosiim,  but  we  doubt 
their  identity. 

S.  simplex  (E.,  K.).  — Frond  subsoli- 
tary;  na\'icul93  smooth,  oblong,  with 
rounded  ends,  in  a  simple  series  within 
flexible  filiform  tubes.  KA.  p.  99.  = 
Naunema  simplex,  E  Inf.  p.  234,  pi.  20. 
f.  12 ;  Monnema  inconspicuum,  Meneg. 
p.  436  ?  Adriatic  Sea.   1-1150"  to  1-570". 

S.  Lenormandi  (K.). — Parasitic,  short, 
subsimple,  in  vroolly  tufts ;  filaments 
achromatic,  for  the  most  part  with  empty 
apices  ;  na^-iculse  quadrangular,  arranged 
in  a  simple  series.  KA.  p.  99.  =  Mon- 
nema Lenormandi,  Meneg.  France. 
Allied  to  S.  tenue,  but  with  smaller 
frustules,  Meneg. 

S.  tenuissimum  (K.).  —  Filaments 
crisped,  subramose,  hyaline,  yery  slen- 
der, densely  interwoyen  into  a  compact, 
bro^^^l  mucous  stratum;  nayiculse  yery 
minute,  linear,  truncate,  in  obsolete 
series.  IvB.  p.  Ill,  pi.  23.  f.  111.  1-3. 
—  3Ionnema  tenuissimum,  Meneg.  Adri- 
atic Sea. 

S.  stn'olatum  (K.).  —  Fronds  tufted, 
green,  crisped,  capillar}^,  fastigiately 
branched ;  filaments  transversely  stri- 
ated, nearly  empty  at  the  base,  filled  at 
the  apex,  crystal-hyaline  throughout ; 
na\'iculse  oblong,  obtuse  in  the  lateral, 
truncate  in  the  front  view.  j3  clavigerum, 
branches  irregular,  covered  with  obovate 
or  clay  ate  ramuli.  KB.  p.  114,  pi.  26.  f.  2. 
=  Monnema  striolatum,  Meneg.  Ger- 
many and  France. 


Genus  MICEOMEGA  (Ag.,  Kiitz.)  (  =  Scliizonema,  Meneg.).  —  Frustules 
naviculoid,  arranged  in  two  or  more  longitudinal  series  within  a  gelatinous, 
filiform  or  setaceous  frond,  or  contained  within  tubes  united  longitudinally 
into  a  compound,  often  membranaceous  frond.  Micromega  is  distinguished 
from  Schizonema  by  its  comj)ound  frond.  We  believe  that  under  one  genus 
have  been  comprised  species  belonging  to  two  distinct  types,  which  perhaps 
ought  to  fonn  two  genera. 

3o 


930 


SYSTEMATIC  HISTORY  OF  THE  USTFUSOEIA. 


The  fii'st  contains  species  having  series  or  files  of  naviculee  surronnded  by 
a  gelatinous  covering,  and  by  their  union  forming  a  compound,  generally 
stout  frond,  externally  furnished  with  a  common  epidermis.  Type,  M.  Smithii. 
The  species  of  this  section  are  highly  gelatinous,  and  consequently  adhere 
firmly  to  paper  in  drj^ing,  are  frequently  of  considerable  thickness  at  the 
base,  and  often  have  their  extremities  lobed,  proliferous,  or  penicillate.  The 
margins,  especially  in  old  specimens,  are  generally  more  or  less  rough  or 
irregular.  The  frustules  are  released  by  the  destruction  of  the  gelatine,  and 
not  by  injmy  to  the  extremities,  as  in  the  ease  of  tubular  fronds.  Each 
series  of  frustules  seems  to  have  its  own  proper  gelatinous  covering,  and  the 
junctions  are  marked  by  faint  longitudinal  lines;  but  these,  which  have 
been  supposed  to  indicate  tubes,  are  often  very  indistinct ;  hence  arises  much 
of  the  difficulty  in  determining  their  proper  genus. 

The  second  section  contains  species  which  have  a  strictly  compound  frond 
of  distinct  tubes  longitudinally  connected,  each  tube  similar  to  a  frond  of 
Schizonema.  The  fronds  are  generally  membranaceous,  and  adhere  imper- 
fectly to  paper;  the  frustules,  arranged  more  or  less  irregularly  in  their 
tubes,  are  liable  to  escape  from  an  opening  at  any  part.  Type,  M.  cornoides. 
If  these  sections,  as  is  probable,  should  hereafter  rank  as  genera,  the  three 
allied  genera  might  be  named  and  characterized  as  follows : — 

1.  MoNis'EMA  (Grev.,  Meneg.)  (=Schizonema,  Ag.,  Kutz.). — Frond  tubular, 
single-tubed. 

2.  ScHizoKEMA  (Ag.,  Grev.,  Meneg.)  (=Micromega,  Ag.,  Kiitz.).  —  Frond 
gelatinous,  not  tubular. 

3.  MicEOMEGA  (Ag.,  Ehr.). — Frond  tubular,  two-  or  more  tubed.  The 
branching  in  Micromega,  especially  in  the  species  belonging  to  the  first 
section,  results  from  the  separation  of  the  series  of  naviculae,  and  is  not  the 
branching  of  a  tube,  as  in  Schizonema. 


*  Frond  gelatinous,  containing  longitu- 
di?ial  series  of  naviculcs. 

MiCEOMEGA  Smithii  (Ag.).  —  Frond 
robust,  setaceous,  gelatinous,  firm,  simple 
below,  much  branched  above,  frustules 
in  longitudinal  series ;  valves  lanceolate, 
acute;  striae  40  in  -001".  =  Schizmiema 
SmWm,  AD.  p.  18;  SD.  ii.  p.  76,  pi.  57. 
f.  362.  Rocks  and  Algae.  Common. 
Fronds  usually  scattered,  pale-yellowish 
olive;  naviculae  disposed  in  subdistant 
files  within  the  colourless  lelly  of  the 
frond.    1-600". 

M.  helminthosum  (Chauv.). — Fronds 
robust,  setaceous,  gelatinous,  lubricous, 
tufted,  much  branched,  with  acute  apices; 
naviculae  in  longitudinal  series;  valves 
elliptic-oblong,  with  rounded  ends ;  stride 
48  in  -001".  =  Schizonema  helminthosum, 
AD.  p.  20;  KA.  p.  103;  SD.  ii.  p.  74, 
pi.  56.  f  355 ;  S.  Arhuscida,  KB.  pi.  27. 
f.  1 ;  Naunema  Arhuscida,  E  Inf. ;  N.fru- 
ticidosum,  KA.  p.  104.  Rocks.  Colour 
olive-brown,  becoming  greenish-grey  and 
without  gloss  in  drying.  1-504".  It 
may  be  known  froni  M.  Sjnithii  by  its 
more  tufted,  often  gregarious,  lubricous 


and  darker-colom'ed  fronds,  and  its  larger 
and  very  obtuse  valves. 

M.  torquatum  (Harv.). — Frond  robust, 
simple  below,  much  divided  above,  ulti- 
mate divisions  much  twisted;  naviculae 
in  longitudinal  files ;  valves  oblong-lan- 
ceolate; striae  40  in  'OOV .  =  Schtzone7na 
torquatum.  Me. ;  SD.  ii.  p.  76,  pi.  57. 
f.  361 ;  aS'.  Smithii,  /3.  torquatum,  Harv. 
Manual,  p.  211;  Micromega  setaceum,  y. 
torquatum,  KA.  p.  107.  Britain.  In  size 
and  colour  it  agrees  with  M.  Smithii,  but 
is  remarkable  for  having  its  branches 
curled ;  its  na'viculae  are  more  distinctly 
in  chains,  shorter  and  broader  in  propor- 
tion to  their  length  than  in  that  species. 
1-720"  to  1-690". 

M.  Poly  dados  (K.). — Frond  setaceous, 
dichotomously  branched ;  branches  elon- 
gated, slender,  rather  rigid;  naviculae 
(membranaceous  ?),  flaccid,  in  distinct 
tubes.  KB.  p.  118,  pi.  28.  f.  1.  Europe. 
Spermatia  eUiptic.  1-1086"  to  1-960". 
Meneghini  unites  this  form  with  M.  tor- 
quatum. 

M.  nehidosiim  (Me.).  —  Frond  slightly 
greenish,  cloudy,  subachromatic,  forming 
an  intricate  mucous  stratum ;  tubes  gela- 
tinous, achromatic,  obsolete;   naviculae 


0¥  THE  KAYICULE.E. 


931 


slender-lanceolate,  rather  obtuse^  loosely 
scattered.  =  Scliizonema  nehulosum,  KA. 
p.  99.  ])alniatia.  '*  Kiitzing  is  right  in 
remarking  that  my  Schizonema  nehulosum 
corresponds  to  M.  torquatum  in  the  form 
and  dimensions  of  the  naviculae.  Al- 
though when  dried  upon  paper  it  only 
forms  a  light  cloud,  yet,  when  diligently 
examined,  it  proves  similar  in  ramifica- 
tion to  Harvey's  species  "  (Me.  p.  445). 
1-1080". 

M.  Wyattii  (Harv.).  —  Frond  carti- 
laginous, setaceous  at  base,  much 
branched  ;  branches  capillary,  erect, 
straight,  with  acute  axils,  tapering  to  a 
fine  point  5  naviculae  lanceolate,  densely 
packed  in  jelly.  =  Schizonema  Wyattii, 
Harv.  Manual,  p.  211.  England.  Forms 
globose  tufts.  This  species  comes  near 
S.  Smithii,  but  is  much  more  slender, 
and  opens  more  readily  and  with  greater 
elasticity  after  being  dried. 

M.  moUe  (S.).  —  Frond  gelatinous, 
simple  below,  membranous  by  cohesion 
above ;  margin  much  divided,  into  acute 
segments ;  naviculae  in  crowded  files ; 
valves  lanceolate,  acute,  with  48  striae 
in  'OQV'.^  Schizonema  molle,  SD.  ii.  p.  77, 
pi.  68.  £  365.  Britain.  -0012"  to  -OOlo". 
The  naviculae  are  very  like  those  of  M. 
helminthosum,  but  the  form  and  structm-e 
of  the  frond  are  altos-ether  diiferent.  The 
frond  is  soft  and  fla 
are  firmly  silicious 

M.  diver  gens  (S.). — Frond  simple  be- 
low, sparingly  di\'ided  or  by  cohesion 
in-egularly  snbmembranous  above;  valves 
oblong-lanceolate,  with  42  striae  in  -001". 
=  Schizonema  diver  gens,  SD.  ii.  p.  76, 
pi.  57.  f.  363.  Larne  Lough.  -0013"  to 
•0018".  Eemarkable  for  the  diftused 
aiTangement  of  the  primary  divisions. 
The  species  is  closely  allied  to  M.  Smithii 
and  M.  toi'quatujn. 

M.  sirospermum  (K.).  —  Frond  rather 
stout,  rigid,  olive,  cartilaginous,  much 
branched;  branches  imequal,  irregular, 
curved,  setaceous;  naviculae  lanceolate, 
in  dense  series,  often  inflated  into  glo- 
bose; spermatia  concatenate.  KA.  p.  109. 
=  Schizo7iema  sirospermum, Me.  England. 
Perhaps  a  state  of  M.  Smithii.    1-720". 

M.  setaceum  (K.).  —  Frond  setaceous, 
olive,  rigid,  subdichotomous ;  branches, 
lateral  and  terminal,  abbreviated,  spine- 
like ;  naviculae  in  crowded  series ;  valves 
lanceolate,  acute.  KB.  p.  117,  pi.  25. 
f.  2,  S.  =  Schizonema  setaceum,  Me.  Adri- 
atic Sea.  1-720"  to  1-696".  Spermatia 
elliptic-globose. 

M.  corymhoswn  (Ag.,  K.).  —  Frond 
arborescent,   rather  stout  at  the  base, 


firm,  rigid,  yellowish,  much  branched; 
branches  setaceous,  rigid,  here  and  there 
corymbose ;  naviculai  in  distinct,  close 
series ;  valves  elliptic-lanceolate.  KB. 
p.  117,  pi.  27.  f.  9.  =  Schizonema  corym- 
hosum,  AD.  p.  21.     England.    1-960". 

M.  hydruroides  (K.). — Fronds  greenish 
or  brown,  ultra-setaceous,  rigid ;  branches 
elongated ;  ramuli  fasciculated,  capillary ; 
naviculae  in  close  series,  minute,  rather 
broad  ;  valves  with  rounded  ends.  = 
Schizonema  hydruroides,  KB.  p.  114,  pi.  26. 
f.  7.     Heligoland.     1-1380". 

M.  Bryopsis  (K.). — Frond  green,  seta- 
ceous, rigid,  branched ;  branches  scat- 
tered, superior  ones  patent,  obtuse ;  na- 
viculae oblong,  trimcate  in  front,  and 
roimded  in  lateral  view.  =  Schizonema 
Bryopsis,  KB.  p.  114,  pi.  26.  f.  8.  Heli- 
goland.    1-680". 

M.  trichocephalum  (K.). — Frond  green- 
ish-yellow, ultra-setaceous,  rigid,  tufted, 
sparingly  branched ;  inferior  branches 
scattered,  simple ;  terminal  ones  crowded, 
curved,  subulate,  capitate ;  naviculae  in 
very  close  series,  minute.  =  Schizonema 
trichocephalum,  KB.  p.  114,  pi.  27.  f.  3. 
Heligoland.    1-1440". 

M.  capitatum  (K.). — Frond  pale  green, 
setaceous ;  branches  elongated,  slender, 
virgate,  with  a  corymbose,  capitate,  acute 
apex ;  naviculae  in  distinct  series,  minute  j 
valves  lanceolate.  =  Schizonema  capita- 
turn,  KB.  p.  114,  pi.  27.  f.  4.  Heligoland. 
1-1200". 

M.  myxacanthum  (K.).  —  Less  stout 
than  M.  corymhosum,  gelatino-cartila- 
ginous,  pale  brown ;  branches  diverging, 
attenuated  at  the  base,  digito-multifid 
at  the  apex ;  divisions  patent,  acute ; 
series  of  lanceolate  naviculae  at  base 
few  and  loose,  above  more  numerous, 
crowded  at  the  apex.  I^.  p.  117,  pi.  24. 
f.  8.  =  Schizonema  myxacanthum.  Me. 
Adriatic  Sea. 

M.  aureum  (K.).  —  Frond  arborescent, 
setaceous  at  base,  rather  rigid,  ochra- 
ceous-yellow,  much  branched,  fastigiate ; 
branches  capillary,  pale,  mucous ;  series 
of  naviculae  and  tubes  distinct,  crowded ; 
valves  lanceolate.  KB.  p.  117,  pi.  27.  f.  8. 
=  Schizonema  aureum.  Me.  Sidmouth. 
1-960". 

M.  obtusum  (Grev.).  —  Frond  robust, 

setaceous,  elastic,  firm,  iiTegularly  dicho- 

tomous,  with  roimded  axils  and  obtuse 

apices ;    naviculae   minute,    crowded  in 

iiTegular  files;  valves  elliptic-oblong.  = 

Schizonona obtusum, GvevlSF.  vi.  pi.  302; 

,  SD.  ii.  p.  78,    pi.  58.   f.  368.      Britain. 

I  The  naviculae  are  excessively  crowded, 

!  and  we  are  uncertain  whether  this  spe- 

3o2 


932 


SYSTEMATIC  HISTOEY  OF  THE  IXFTJSOEIA. 


cies  oiiglit  not  rather  to  be  placed  in 
Scliizonema.  "Frond  thicker  than  a 
hog-'s  bristle,  and  nearly  of  equal  diameter 
throughout ;  colour  brownish-yellow,  be- 
coming yellowish-green  in  dying.  A 
handsome  and  distinct  species,  well 
marked  by  its  roimdish  axils  and  obtuse 
apices  "  (Haryey). 

IsL  Blyttii  (Ag.). — Frond  elongated, 
filiform,  many  times  irregularly  dicho- 
tomous,  with  romided  axils,  cylindrical, 
not  attenuated;  nayiculae  in  nimierous 
parallel  series.  AD.  p.  23.  =  Scliizonema 
Blyttii,  Me.  Norway.  An  elegant  and 
remarkable  species ;  fronds  erect. 

M.  mesoglceoides  (K.).  —  Frond  stout, 
very  gelatinous,  greenish,  irregularly 
branched ;  branches  dense,  numerous, 
unequal ;  ramuli  incrassated  at  the  apex, 
patent;  nayiculfe  rather  irregularly  ag- 
gregated, dense ;  yalyes  with  attenuated 
apices.  =  Scltizojiema  mesoqloeoides,  ELA. 
p.  103.     Aberdeen.    1-600''. 

M.  humile  (K.). — Frond  parasitic,  yery 
short,  tufted,  erect,  subramose ;  branches 
with  obtuse,  hyaline  empty  apices ; 
nayiculse  acute,  linear-lanceolate,  ar- 
ranged in  two  to  four  series.  =  Schizo- 
nema  humile,  KB.  p.  Ill,  pi.  23.  f.  7. 
Adriatic  Sea.  Nayiculae  in  front  yiew 
linear,  truncate.     1-1200". 

M.  papillosum  (Me.).  —  Frond  para- 
sitic, small,  yery  mucous,  gTeen;  fila- 
ments ultra-setaceous,  subsimple  or  fur- 
nished with  acute  spiniform  ramuli, 
eyerywhere  covered  with  very  minute, 
regularly  disposed  papillre;  valves  nar- 
row-elliptic, rather  obtuse.  =  Scliizonema 
p)apillosum,  Me.  p.  452.  Dalmatia.  Na- 
viculcG  in  series,  four  times  as  long  as 
broad,  in  front  view  slightly  elliptic, 
with  truncate  ends.  The  papillnB  appear 
hemispherical  or  slightly  conical,  and 
are  arranged  in  quincimx.  Me. 

M.  Stalianum  (Me.,  K.). — Fronds  pa- 
rasitic, gelatinous,  green  or  greenish- 
brown  ;  filaments  setaceous,  elongated, 
irregularly  branched;  branches  diverg- 
ing, short;  naviculse  in  series,  six  times 
as  long  as  broad ;  valves  elongated- 
elliptic,  obtuse.  KA.  p.  106.  =  Schizo- 
nema  Stalianum,  Me.  p.  452.  Dalmatia. 
Is  very  mucous  and  adheres  strongly  to 
paper ;  naviculse  in  front  view  exactly 
linear.     1-420"  to  1-360". 

M.  Corinalili  (Me.). — Frond  parasitic, 
small,  green ;  filaments  subsimple,  se- 
taceous ;  frustules  minute,  five  times 
as  long  as  broad;  valves  narrow-ellip- 
tic. =  Schizonema  Corinaldi,  Me.  p.  453. 
Marseilles.  Naviculae  in  series,  in  front 
view  exactly  linear.  The  threads,  slightly 


mucous,  are  usually  simple ;  the  few  ra- 
mifications are  short  and  divaricate,  Me. 

M.  fastigatum  (K.). — Frond  setaceous, 
olivaceous,  much  branched ;  ultimate 
branches  subcorymbose,  ^^dth  lanceolate- 
acuminate  apices ;  naviculag  minute,  ob- 
long, obtuse,  in  loose  series.  I'LV.  p.  108. 
Torquay.     Secondary  tubes  obsolete. 

M.  medusinum  (K.). — Frond  cartila- 
gino-gelatinous,  hyaline,  brown,  turgid 
at  the  base,  separated  at  the  apex  into 
penicillate  fibres ;  series  of  naviculas 
loosely  entangled,  intermixed  with  flex- 
uose  longitudinal  fibres.  KB.  p.  118, 
pi.  25.  f.  6.  =  Scliizonema  medusiniwi,  Me. 
Adriatic  Sea.     Valves  lanceolate. 

M.  liyalinum  (K.). — Frond  colourless, 
hyaline,  gelatino-cartilaginous,  soft,  seta- 
ceous at  base,  much  branched ;  branches 
attenuated,  capillary,  empty  at  the  apex ; 
series  of  na^dculge  few,  loose,  inteimixed 
with  a  few  fibres ;  naviculae  minute ; 
valves  oblong-lanceolate,  obtuse.  KB. 
p.  117,  pi.  24.  f.  Q.^=  Scliizonema  hyalinum, 
Me.  Adriatic  Sea.  Navicidse  1-960"  to 
1-780";  in  front  view  truncate. 

M.  tenellum  (K.)-  —  Frond  colourless, 
hyaline,  gelatino-cartilaginous,  setaceous, 
branched,  subdichotomous  ;  branches 
delicate  and  empty  at  the  apex ;  series 
of  slender  na^dculae  and  internal  tubes 
distinct.  I^.  p.  117,  pi.  24.  f.  7.  =  Schi- 
zonema tenellmn,  Me.     Adriatic  Sea. 

M.  Hyalopms  (K.). — Frond  colomless 
and  hyaline  at  the  base,  above  greenish, 
narrow,  much  branched;  branches  fas- 
tigiate,  subacute,  full  to  the  apices ;  lower 
series  of  naviculae  lax,  superior  crowded ; 
valves  lanceolate.  KB.  p.  117,  pi.  25. 
f.  6.  =  Schizone7na  Hyalopus,  Me.  Adri- 
atic and  French  Seas,  Jersey.  Internal 
tubes  obsolete;  naviculae  in  front  yiew 
oblong,  truncate ;  spermatia  immersed, 


M.  laciniatum  (Harvey).  —  Frond  ro- 
bust, setaceous  below,  incrassated  above, 
yery  tender  and  gelatinous,  cleft  into 
numerous  tapering  branches;  na^dculae 
very  minute,  in  close  files  ;  valves  ellip- 
tic-lanceolate, ohiu&e.  =  Scliizonema  laci- 
nicdum,  Harv.  Man.  p.  210;  SD.  ii.  p.  79, 
pi.  59.  f.  371 ;  S.  sco^mrium,  KB.  p.  114, 
pi.  27.  f.  7.  Europe.  Frond  cleft  above 
into  nimierous  irregular  jagged  branches. 
1-600". 

'^L  ptarasiticwn  (GrifF.,  K.). — Frond 
gelatinous,  capillary,  tufted,  much  and 
intricately  branched  from  the  base; 
branches  flexuose,  with  rounded  axils; 
frustules  crowded  in  distinct  files ;  valves 
lanceolate,  acute.  KB.  p.  116,  pi.  27.  f.  2. 
=  Schizonema  ^^^''('sitictwi,  Harv.  Man, 


OF  THE  NAVICULE.^. 


933 


p.  213 ;  SD.  ii.  p.  79,  pi.  59.  f.  371.  Eu- 
rope. Colour  pale  yeUowisli,  sometimes 
brownish.     Naviculge  1-1380". 

M.  investens  (Montagiie).  —  Fronds 
parasitic,  minute,  lubricous,  brown, 
opaque,  fasciculated  j  filaments  dilated 
at  the  base,  diiiusely  ramose ;  branches 
anastomosing ;  naviculse  large,  in  one  or 
two  s,ei::\QS,.  =  Schizonema  investens,  Mont. 
Annales  des  Sci.  Nat.  1850,  p.  308. 
Guiana.     Navicul^e  with  two  nuclei. 

M.  mucosum  (K.). — Frond  soft,  highly 
mucous;  filaments  contiguous  and  con- 
fluent ;  branches  iiTegular ;  naviculse  in 
few  files;  valves  elliptic-oblong,  with 
rounded  ends,  delicately  striated.  = 'S'c/»- 
zonema  mucosum,  IvB.  p.  115,  pi.  26.  f.  9 ; 
SD.  ii.  p.  75,  pi.  57.  f.  360.  Adriatic  Sea, 
England.  This  species  can  scarcely  be 
the  Schizonema  tenue  of  Agardh,  as 
Kiitzing  has  supposed. 

M.  jKtrvum  (Me.). — Frond  olive-green, 
-mucous;  filaments  hyaline,  simple  (?), 
much  entangled  and  cm-ved  ;  navicidse 
in  distinct,  loose,  oblique  or  straight 
series  ;  valves  lanceolate.  =  Schizonema 
parvum,  Me  KA.  ^.  100.  Venice,  Cay- 
enne. Naviculae  in  front  view  linear, 
rectangular.     1-1200". 

M.  3Ieneghinii.  —  Frond  green,  very 
gelatinous;  filaments  very  hyaline,  lu- 
bricous, fastigiately  divided  and  laci- 
niated ;  naviculse  lanceolate,  in  loose, 
rather  distant  sevies.  =  Scliizonema  bom- 
hycinum,  Me  KA.  p.  100.  Venice. 
1-1200". 

M.  Kiitzingii.  —  Fronds  tufted,  intri- 
cate, much  branched ;  filaments  hyaline, 
with  rather  acute  apices;  naviculse  in 
distinct  series ;  valves  lanceolate,  acute. 
=  Schizonema JloccosiwiyJiH.  p.  113, pi.  24. 
f.  3.  Germany.  Naviculse  in  front  view 
oblong,  truncate.     1-600". 

M.  crispum  (Mont.).  —  Fronds  small, 
crisped,  capillary,  green,  branched :  fila- 
ments obtuse,  dilated  and  multifid  at 
the  apex ;  naviculse  very  minute,  much 
crowded  in  obsolete  sevies.  =  ScJnzone7na 
crispum,  KB.  p.  113,  pi.  29.  f.  71.  Auck- 
land Islands. 

M.  plumosum  (K.).  —  Frond  tufted, 
wavy,  rather  curled,  green,  fastigiately 
branched ;  filaments  densely  fiUed  at  the 
ends,  dilated,  multifid ;  naviculse  distinct, 
very  minute ;  valves  oblong-eUiptic,  vdih. 
rounded  ends.  =  Schizonema  plumosum, 
KB.  p.  113,  pL  26.  f.  1.  Europe.  Navi- 
culse in  front  "^dew  oblong,  truncate. 
1-1440". 

M.  Zanardinii  (Me.). — Frond  very  fine, 
pale  green ;  filaments  capillary,  gradually 
separating     into    corymbose    arachnoid 


branches  of  one  series ;  naviculse  in  loose 
series,  four  times  as  long  as  broad; 
valves  elli-ptic.  =  Schizone77ia  Zanardinii, 
Me.  p.  453.  Venice.  Navicidse  in  front 
view  exactly  linear.  Fronds  in  globular 
tufts,  which,  dried  upon  paper,  form 
imiform  spots,  in  which  the  separate 
threads  can  only  be  distinguished  by  a 
lens.  In  its  mode  of  ramification  it  re- 
sembles M.JlageUiferum,  Me. 

IsL.  jiagelliferum  (K.).  —  Fronds  very 
minute,  tufted,  parasitic,  floccose,  capil- 
lary; branches  erect,  separated  at  the 
apex  into  flagelliform  fibres;  series  of 
the  verv  minute  naviculte  and  internal 
tubes  distinct.  KB.  p.  116,  pi.  24.  f.  4. 
=  Scliizonema  JlageUiferum,  Me.  1-1920" 
to  1-1560". 

M.  jioccosum  (K.).  —  Frond  minute, 
subcapillary,  branched,  rather  delicate, 
gelatinous ;  series  of  the  long,  obtuse 
and  trimcate  naviculse  and  internal  tubes 
verv  distinct.  KB.  p.  116.  Adriatic  Sea. 
1-720". 

M.  intricaium  (K.).  —  Frond  delicate, 
subgelatinous,  nebulose,  pallid  yeUow, 
irregularly  branched ;  branches  patent, 
upper  ones  abbreviated;  series  of  navi- 
cidse loose,  intermixed  with  very  fine 
longitudinal  fibres ;  naviculse  oblong, 
obtuse,  very  minute,  KB.  p.  116,  pi.  26. 
f.  b.  =  Schizonema  intricatum.  Me.  Eng- 
land.    1-1440"  to  1-680". 

M.  homhycinum  (K). — Frond  pale  yel- 
low, contorted,  twisted,  much  branched, 
capillary ;  naviculse  remotely  concate- 
nate, inconspicuous,  and  verv  minute. 
KB.  p.  116,  pL  26.  f.  6.  =  Schizonema 
homhycinum,  Me.    Europe,  (xiv.  4-3, 44.) 

M.  ?  Agardhii  (E.).  —  NaviculfB  very 
naiTow,  acute,  arranged  in  a  simple 
series  ^vdthin  a  proper  tube ;  tubes  fas- 
cicidately  joined  into  a  filament.  =  ASb/ii- 
zonema  Agardhii,  E  Inf.  p.  238,  pi.  20. 
f.  16.  North  Sea.  (x.  208.)  Professor 
Kiitzing  unites  this  species  with  31.  hom- 
hycinum; but  the  frustules  are  apparently 
(judging  from  the  respective  figures) 
much  larger. 

M.  patens  (K.). — Frond  minute,  para- 
sitic, floccose-capillary,  soft,  gelatinous ; 
branches  divergent  or  patent,  with  ob- 
tuse apices;  series  of  naviculse  and  in- 
ternal tubes  distinct  ;  naviculse  very 
minute.  KB.  p.  116,  pi.  24.  f.  b.  =  Schi- 
zonema patens.  Me.     1-2400". 

M.  Uneatum  (K.). — Frond  decumbent, 
intricate,  capiUaiy,  olivaceous,  tenacious, 
lubricous,  subramose;  branches  at  the 
apex  attenuated,  curved,  rather  obtuse ; 
series  of  the  very  minute  lanceolate 
naviculse   distinct/  KB.  p.  116,  pi.  23. 


934 


SYSTEMATIC  HISTORY  OF  THE  INFUSORIA. 


f.  4.  =  Schizonema   lineatum,  Me.     Dal- 
matia.     1-1320"  to  1-1200". 

M.  gracillimmn  (S.). — Frond  capillary, 
simple  below,  sparingly  branched  and 
submembranous  towards  the  apices ;  na- 
viculPD  crowded  in  irregular  files ;  valves 
lanceolate,  acute.  =  Schizonema  gracilli- 
mum,  SD.  ii.  p.  79,  pi.  59.  f.  372.  Tor- 
quay.    -0009". 

M,  IJlyricum  (K.).— Fronds  forming  a 
dull-,  obscure-green,  mucous,  intricate 
stratum ;  filaments  very  fine,  simple  (?), 
soft,  hyaline ;  naviculse  acuminate,  lan- 
ceolate, in  dense  series,  indistinct  when 
dried.  =  Schizonema  Illyricum,  KB.  p.  Ill, 
pl.22.  f.  3.    Trieste.    1-1680"  to  1-1440". 

M.  minufmn  (K.). — Frond  parasitic, 
very  short,  fine,  decumbent,  subramose  ; 
branches  tapering  to  acute  apices ;  navi- 
culae  acute,  lanceolate,  in  few  (2  to  4) 
series.  ■=  Schizonona  tninutum,  KB.  p.  Ill, 
pi.  23.  f.  5.  Adriatic  Sea.  Naviculae  in 
front  view  linear.     1-1176". 

2  *  Frond  composed  of  tubes  longitudi- 
nally connected. 

M.  comoides  (Grev.). — Filaments  dirty 
brown,  coarse,  membranaceous,  elongated, 
twisted,  composed  of  parallel  tubes ; 
frustules  crowded ;  valves  oblong-lan- 
ceolate ;  striae  48  in  -001".  =  Schizone77ia 
comoides,  Grev.  (scarcely  of  Agardh, 
certainlv  not  the  Conferva  co7noides  of 
DiUw;^Ti);  Hook.  Br.  F.  p.  413 ;  SD.  ii. 
p.  75,  pi.  57.  f.  358 ;  Schizonetna  araneo- 
sum,  KB.  p.  113,  pi.  25.  f.  9.  Flat  rocks, 
often  in  vast  quantities.  It  is  very  re- 
markable that  this  coarse,  dirty-looking 
species  should  ever  have  been  confounded 
with  the  Conferva  comoides,  Dillw.  The 
latter,  we  were  assured  by  Mr.  Dillw^n, 
was  totally  imlike  the  present  species, 
and  was  correctly  described  by  him. 
Unfortunately  Mr.  Diilw}Ti  was  unable 
to  find  an  original  specimen  of  his  spe- 
cies, but  he  believed  that  a  very  slender 
simple-tubed  Schizonema,  of  a  bright 
brown  colour,  which  we  once  found  in 
great  abimdauce  in  April,  on  the  rocks 
outside  the  Mumble  Lighthouse  near 
Swansea,  was  the  true  Conferva  co?noides. 
The  present  species  is  usually  twisted  in 
a  rope-like  manner,  retains  its  colour  in 
drying,  is  very  opaque,  and  does  not 
adhere  to  paper. 

M.  ramosissimimi  (Ag.), — Frond  robust, 
film,  membranaceous,  much  branched; 
branches  short,  swelling  upwards ;  frus- 
tules minute,  densely  arranged  in  distinct, 
parallel  tubes ;  valves  oblong-lanceolate. 
AD.  p.  22.  =  Schizonema  ramosissimum, 


Harv.  Man.  p.  210 ;  SD.  ii.  p.  78,  pi.  59. 
f.  369.  Europe.  Somewhat  resembles 
M.  comoides  in  appearance,  but  is  less 
elongated  and  less  twisted.  Does  not 
adhere  to  paper. 

M.  apiculatum  (Grev.,  Ag.). — Frond 
robust,  ultra-setaceous,  cartilaginous, 
irregularly  dichotomous  ;  branches  with 
clavate  ends,  terminated  by  a  mucro ; 
secondary  tubes  distinct;  naviculse  mi- 
nute, crowded;  valves  lanceolate.  AD. 
p.  22;  KB.  p.  117,  pL  27.  f.  10.  =  Schi- 
zonema  apiculatum,  AA.  p.  11 ;  Harv. 
Manual,  p.  210.     Scotland. 

M.  corniculatum  (Ag.). — Frond  very 
stout,  cartilaginous,  erect,  rigid,  subdi- 
chotomous,  much  branched  above ;  ulti- 
mate ramiili  subulate  and  spine-like; 
naviculse  slender,  lanceolate,  contained 
in  distinct  secondary  tubes.  AD.  p.  24 ; 
I^,  p.  118,  pi.  28.  f.  2.  =  Schizone7na  cor- 
niculatum. Me.  Adriatic  Sea.  Habit  of 
a  small  Fucus.     1-600". 

M.  penicillatiwi  (Chaiiv.,  Ag.). — Frond 
thick  and  simple  at  the  base,  divided  at 
the  apex  into  veiy  numerous,  penicillate, 
fastigiate,  capillary  branches.  AD.  p.  23. 
=  Schizonema  penicillatum,  Chauvin  ;  M, 
corniculatum  /3,  KA.  p.  109.     France. 

M.  pallidum  (Ag.). — Frond  pulvinate, 
rigid,  subcartilaginous,  stout,  much 
branched;  ramuli  suberect,  abbreviated, 
obtuse;  navicidse  minute,  in  lax  series 
within  distinct  secondary  tubes.  AD. 
p.  23 ;  KB.  p.  118,  pi.  28.*^  f.  3.  =  Schizo- 
nema pallidum.  Me.  Adriatic  Sea. 
(xiv.  39-42.)  Tufts  hemispherical, 
dense ;  colour  pallid,  verging  on  brown- 
ish yellow.     1-720"  to  1-696". 

M.  chondroides  (K.). — Frond  minute, 
cartilaginous,  olive-colom'ed ;  teiminal 
branches  aggregated,  clavate,  obtuse, 
here  and  there  with  hair-like  spines; 
series  of  naviculae  and  secondary  tubes 
very  distinct,  crowded;  naviculse  mem- 
branous, flaccid,  minute.  KB.  p.  118, 
pi.  25.  f.  8.  =  Schizonema  chondroides,  Me. 
Adriatic  Sea.  1-1380"  to  1-1320".  Sper- 
matia  immersed,  globose. 

M.  spinescens  (K). — Frond  dwarfish, 
setaceous,  slightly  dilated  upwards ;  ter- 
minal ramuli  acute,  spine-like  ;  series  of 
naviculae  and  secondary  tubes  crowded, 
very  distinct;  valves  lanceolate.  KB. 
p.  118,  pi.  27.  f.  11.  =  Schizonema  spines- 
cens, Me.  Adriatic  Sea.  Navicidae  in 
front  view  oblong,  trimcate.  1-960"  to 
1-720".     Spermatia  internal,  globose. 

M.  albicans  (K.).  —  Frond  setaceous, 
whitish  or  olive-gTeen ;  branches  and 
ramuli  equal  in  thickness,  fasciculated 
or  whorled ;  naviculfe  in  distinct  series, 


OF  THE  ACTLNISCE^. 


935 


lanceolate;  secondary  tubes  distinct.  KB. 
p.  118,  pi.  27.  f.  12.  =  Schizonema  albicans, 
Me.  Adriatic  Sea.  1-1200"  to  1-1080". 
Meneghiui  describes  the  valves  as  broadly 
elliptic. 

M.  Berheleyi  (K.).— Frond  tufted,  dull 


ojiye-brown ;  filaments  setaceous,  rather 
rigid,  branched ;  branches  erect,  attenu- 
ated ;  naviculse  large;  valves  eUiptic- 
oblong,  in  very  distmct  secondary  tubes. 
KA.  p.  106.  Torquay.  NavicuL-B  in 
front  \dew  paraUelogramic.     1-1080". 


FAMILY  XIX.— ACTimSCE^. 

Individuals  silicious,  furnished  with  radiating  spines.  Marine.  The  Acti- 
nisceae  bear  little  or  no  resemblance  to  the  Diatomaceae,  and  ought  to  be  ex- 
cluded from  them.  M.  de  Brebisson  thinks  they  would  be  more  appropriately 
placed  near  the  Arceila,  EugljT3ha,  or  some  allied  genus.  On  the  other  hand, 
Professor  Bailey  would  refer  them  to  the  Polycystina. 

Genus  ACTINISCUS  (Ehr.).— Frustules  solid,  star-like.  Actiniscus  differs 
from  Dictyocha  and  Mesocena  in  having  a  solid  centre  or  body  from  which 
rays,  varying  in  number  and  form,  diverge. 


Actiniscus  Sirius  (E.).  —  Rays  6, 
acute,  winged  at  the  base.  EM.  pi.  33. 
lo.  f.  1.  l-lloO".  Alive,  Norway ;  fossil, 
America.  The  rays  seem  to  arise  from 
the  disc,  and  not  from  the  margin. 

A.  Pentasterias  (E.). — Rays  5,  acute, 
not  (or  but  partially)  exserted.  EM. 
pi.  35  a.  23.  f.  1.  1-1150".  Alive, 
Norway ;  fossil,  Greece  and  America. 

A.  Tetrasterias  (E.). — Rays  4,  acute, 
not  (or  but  partially)  exserted.  EM. 
pi.  18.  f.  62.  1-1008".  Virginia.  The 
last  two  forms  may  be  varieties  of  A. 
Sinus. 

A.  ?  Stella  (E.).  —  SteUate,  with  6, 
marginal,  obtuse  rays  or  teeth.  =  Dicty- 


ocha, E.  1838.  Fossil.  Eui'ope  and 
Africa, 

A.  ?  quinarius  (E.). — Stellate,  with  5, 
marginal,  obtuse  rays  or  teeth.  1-3120". 
Fossil,     ^gina. 

A.  ?  Rota  (E.).— Wheel-Hke,  with  10, 
short,  obtuse,  spoke-like  rays.  1-1920". 
Oran. 

A.  ?  Discus  (E.). —  Disciform ;  centre 
smooth ;  rays  8,  marginal,  not  exserted. 
1-2304".  Oran.  According  to  Ehren- 
berg,  the  last  four  species  may  belong  to 
Phytolitharia. 

A.  ?  Lancearius  (E.). — Stellate,  with 
8  exserted,  lanceolate  rays,  and  some 
central  shorter  ones.     1-240". 


Genus  DICTYOCHA  (Ehr.). — Frustules  free,  spinous,  reticulately  per- 


forated ;  foramina  large. 

*  Foramina,  or  cells,  two  or  three. 

Dictyocha  Ponticulus  (E.).  —  Frus- 
tules oblong,  unarmed,  transversely 
divided  into  2  cells.  1-432".  Fossil. 
Bermuda. 

D.  Quaclratum  (E.). — Subquadrate  or 
oblong,  transversely  divided  into  2  cells, 
a  spine  at  each  end.  1-480".  Bemiuda. 
These  two  forms  were  first  obsei-ved  and 
figured  by  Professor  Bailey. 

D.  Pons  (E.). — Roimdish,  ^dth  2  cells 
and  4  spines.     1-504".     Oran. 

D.  triacantha  (E.). — Triangular,  with 
spinous  angles  ;  cells  3.  unarmed.  Mary- 
land. 

D.  tri^iyla  (E.).  —  Roundish,  with  4 
irregular  spines;  cells  3,  unarmed. 
1-492".     Oran. 

D.  trifenestra  (E.).  —  Quadi-ate,  4- 
spined;  cells  3,  dentate.  Recent  and 
fossil,     (xv.  35.) 


D.  Ahijssarum  (E.). — Frustides  trian- 
gular, with  2  cells ;  spines  3 ;  1  ceU  fm*- 
nished  with  an  internal  tooth.  EB. 
1854,  p.  238.     Atlantic. 

2*  Diamond-shaped  or  quadrate  ;  4- 
spined;  foramina  4  or  more. 

D.  P'ihula  (E.).  —  Cells  4,  unanned. 
1-1150"  to  1-560".  Recent  and  fossil. 
(XV.  34.) 

D.  Epiodon  (E.).  —  Resembles  D. 
Fibula,  but  the  cells  are  fimaished  with 
a  tooth.     Recent  and  fossil. 

D.  abnormis  (E.). — Cells  5,  unequal, 
all  marginal.     1-1080".     Fossil. 

D.  Crux  (E.).  —  Four  unanned  cells 
round  a  central  one.     1-624".     Fossil. 

D.  Staurodon  (E.).  —  Resembles  D. 
Crux;  but  each  marginal  cell  bears  a 
tooth.     1-576".     Fossil.     Virginia. 

D.  mesophthalma  (E.).  —  Resembles 
the  two  preceding  species ;  but  each  mar- 


936 


SYSTEMATIC  HISTOEY  OF  THE  INFUSOEIA. 


ginal  cell  has  2  opposite  teeth,  whicli 
constrict  it.     1-372".     Fossil.     Sicily. 

D.  bqmrtita(E.). — Resembles  D.  Cmx, 
but  has  2  minute  cells  in  the  centre. 
1-504".     Fossil.     Oran  and  Sicily. 

D.  superstructa  (E.). — Spines  4;  cells 
9, 4  marginal.     1-600".    Fossil.     Sicily. 

3*  Spines  6  (2  usually  longer). 

D.  hitemaria  (E.). — Cells  Q,  aU  mar- 
ginal, the  3  largest  next  each  other. 
1-432".     Antarctic  Ocean. 

D.  Hexathyra  (E.).— Cells  Q,  5  mar- 
ginal and  1  central.  1-864.  Fossil. 
Sicily. 

J)^  Speculum  (E.). — Six  unamied  cells 
round  a  central  one.  Common,  both 
recent  and  fossil.    1-860".    (xn.  62,  63.) 

D.  gracilis  (K.). — Resembles  D.  Sp>e- 
culum ;  but  the  spines  are  elongated  and 
slender.     Recent. 

D.  diommata  (E.). — Six  unarmed  cells 
round  2  central  ones.  1-660".  Fossil. 
Virginia. 

D.  aculeata  (E.). — Resembles  D.  Spe- 
culum; but  each  marginal  cell  bears  a 
tooth.     Common,  both  recent  and  fossil. 

D.  Binoculus  (E.).  —  Resembles  D. 
aculeata,  but  has  2  minute  ceUs  in  the 
centre.     1-444".     Fossil,     ^gina. 

D.  libera  (E.). — Cells  unarmed,  7  mar- 
ginal and  2  central.    1-600".    Maryland. 

1).  triommata  (E,). — Cells  unarmed, 
6  marginal  and  3  central.  1-864". 
Virginia. 

D.  Haliomma  (E.).— Cells  10,  7  mar- 
ginal and  3  central.     1-840".     Oran. 

D.  liemisplicerica  (E.). — Hemispherical, 
6-spined ;  1 2  cells,  in  two  circles,  round 
a.  central  one  ;  the  inferior  apertm^e  half 
closed  by  6  marginal  teeth.  1-744". 
Bermuda.  D.  triommata  and  J),  diom- 
7nata  resemble,  in  their  turgid  habit, 
this  species. 

4*  Spines  more  than  6. 
D,  septenaria   (E.). — Spines  7;  cells 


unarmed,  7  marginal  and  1  central. 
1-864".     Oran. 

D.  Ornamentum  (E.). — Resembles  D. 
septenaria ;  but  each  marginal  cell  bears 
a  tooth.     1-444".     Fossil.     Sicily. 

D.  heptacanthus  (E,). — Spines  7 ;  cells 
13,  7  of  them  marginal.  1-552".  Fossil. 
Greece. 

D.  octonaria  (E.). — Habit  of  D.  Orna- 
mentum, with  8  spines;  marginal  cells 
iiTegular,  fewer  in  number  at  that  part 
where  the  spines  are  increased,  and  with 
a  very  large  centi*al  cell.  1-1152"  ex- 
clusive of  spines.  Perhaps  a  monstrous 
variety  of  D.  Ornamentum. 

D.  Stauracanthus  (E.). — Eight-spined ; 
4  marginal,  dentate  cells,  roimd  a  centi'al 
one.     1-648".     Fossil.     America. 

B.polyactis  (E.).— Rays  9  or  10;  10 
marginal  cells  and  1  central,  arranged  in 
a  reticulate  steUate  fonn.   In  chalk-marl. 

5*  Pentagojial ;  angles  acute,  hut  not 
spinous. 

D.  elegans. — Pentagonal,  perforated  by 
numerous  small  ceUs  and  7  central  large 
ones,  of  which  one  occupies  the  centre. 
1-912".     Fossil.     Caltanisetta,  Sicily. 

Doubtful  or  obscure  Species. 

D.  Navicula  (E.). — Cells  8  ;  figm-e  ob- 
long, obtuse,  cylindrical,  reticular,  -udth 
a  median  septum  like  a  Na^dcula.  Fossil 
in  chalk  marl.  Ehrenberg's  figure  re- 
sembles D.  Ponticidus. 

D.  ?  sple?idens  (E.). — Oblong,  tabular, 
with  dentate  apertm-es  (cells),  13  in 
number.  If  it  be  calcareous,  it  is  similar 
to  Coniopelta. 

D.  anacantha  (E.).  —  Resembles  D. 
Speculum,  with  obsolete  spines.  EB. 
1854,  p.  238.  North  America.  Perhaps 
a  variety. 

D.  JErebi  (E.). — Resembles  D.  Specu- 
lum, with  small,  subequal  spines ;  walls 
of  the  cells  thin.  E.  I.  c.  North  America. 
A  doubtful  species ;  perhaps  a  variety. 


Genus  MESOCENA  (E.). — Frustules  free,  each  forming  a  ring,  which  is 
mostly  margined  with  spines  or  teeth.  Mesocena  resembles  Bictyocha,  but  is 
destitute  of  its  central  reticulation. 


Mesocena  heptagona  (E.). — Frustules 
annular,  wdth  7  external  teeth.  EM. 
pi.  20.  1.  f.  49.  (xii.  71.)  Actiniscus  ?, 
E.     Peru. 

M.  octogona  (E.). — Frustules  annular, 
with  8  external  teeth.  Peru.  As  this 
form  differs  from  M.  heptagona  merely 
by  its  additional  tooth,  it  is  probably  a 
variety. 


M.  bisoctonaria  (E.). — Frustules  annu- 
lar, with  8  external  teeth,  and  as  many 
internal  ones  alternating  with  them. 
=  M.  bioctonaria,  KA.  p.  142 ;  EM. 
pi.  35  A.  18.  f.  10.     In  Peruvian  guano. 

M.  binonaria  (E.). — Frustules  annidar, 
with  9  external  teeth,  and  as  many 
internal  ones  alternating  with  them. 
EM.  pi.  35  A.   18.  f.  9.      In  Peruvian 


ADDENDA. 


937 


guano.  Probably  a  variety  of  the  pre- 
ceding species. 

M.  Cir cuius  (E.). — Cell  circular ;  mar- 
gin tuberculated.  1-576".  EM.  pi.  19. 
f.  44.     In  Greek  marl. 

M.  Diodon  (E.). — In  tbe  form  of  a 
smooth  elliptic  ring,  armed  at  each  end 
with  a  small  tooth.  1-396".  EM. 
pi.  33.  15.  f.  18.    Maryland. 


M.  elHptica  (E.).  —  Frustules  elliptic, 
with  4  teeth.  1-624"  to  1-456".  EM. 
pi.  20.  1.  f.  44.     Fossil.     Zante. 

M.  triangula  (E.). — Triangular,  with 
rough  sides,  and  mucronate  apices.  EM. 
pi.  22.  f.  41.     Fossil,  chalk-marl. 

M.  ?  Spongiolithis  (E.). — An  elliptic 
ring,  with  4  slight  alternating  swellings. 
1-492". 


GENEEA  OF  DOUBTFUL  POSITIOJ^T. 

Genus  EUCAMPIA  (Ehr.).  —  Frustules  hyaline,  imperfectly  silicious, 
cuneate,  without  terminal  puncta,  united  into  a  jointed,  spiral  filament. 
Marine.  This  genus,  placed  by  Ehrenberg  and  Kiitzing  with  the  Desmidiese, 
was  judiciously  removed  by  Professor  Smith  to  the  Diatomaceae,  with  which 
it  agrees  in  structure  and  in  the  colour  of  internal  matter.  Professor  Smith, 
however,  considered  it  allied  to  Meridion  ;  in  our  opinion  it  is  more  nearly 
related  to  the  Biddulphiese,  as  shown  by  the  absence  of  costae  and  terminal 
puncta,  ^its  dotted  valves,  and  their  prominence  in  the  front  view. 

EucAisiPiA  ZocUacus  (E.). —  Frustules,    f.  299.     Europe,     (n.  43.) 
in  fi'ont  view,  with  the  j  unction-margins        E.  Britannica  (S.). — Frustules  cune- 
deeply  shiuated,  so  as  to  form  foramina    ate,  not  excavated.     SD.  ii.  p.  25,  pi.  61. 
between  the  joints.     E.    Leb.  Ki-eide-    f.  378.     Europe.     Stomach  of  Pectens. 
thierchen,  pi.  4.  f.  8;  SD.  ii.  p.  25,  pi.  60.  | 

Genus  LITHODESMIUM  (Ehr.).— Fmstules  not  ceUulose,  united  into  a 
joiated,  prismatic  wand ;  valve  triangular,  with  one  side  plane,  and  the  others 
undulated.  Lithodesmium  was  placed  with  the  Desmidieae  by  Ehrenberg, 
and  with  the  Diatomaceae  by  Kiitzing.  Its  non-cellulose  structure,  however, 
prevents  our  associating  it  with  the  Anguliferae,  as  proposed  by  the  latter. 


Lithodesmium  undulatum  (E.).  — 
Frustules  smooth,  very  pellucid ;  valves 
with   obtuse  angles.     E.  Leb.  Kreide- 


thierchen,    1840,    p.    75,  pi.   4.   f.    13. 
Marine.     Cuxhaven.     (n.  41, 42.) 


Genus  MICROTHECA  (Ehr.). — Frustules  simple,  free,  compressed,  qua- 
di-ate.  Placed  by  Ehrenberg  and  Kiitzing  ^dth  the  Desmidieae.  We  remove 
it  to  the  Diatomaceae,  because  of  its  marine  habitat  and  golden  colour ;  little, 
however,  is  known  about  it,  and  its  nature  is  doubtful. 

;Miciiotheca  octoeeras    (E.).  —  Cell    colour.      E  Inf.  p.   164,   pi.  12.  f.  10. 
quadrate,  hyaline,  with  four  spines  at    Marine.     Kiel.     (vin.  31.) 
each  end;  internal  matter  of  a  golden 


ADDEInTDA  TO  THE  DIATOMACE^. 

Cyclotella  pertmuts  (B.). — Valves  I  cellulate  or  punctate;  cells  radiant.     B. 
minute,  slightly  convex;  surface  minutely  |  on  Mic.  Forms  in  the  Sea  of  Kamtschatka. 

The  following  corrections  and  addition  to  Cyclotella  are  adopted  fi'om  Professor 
Amott's  paper  in  JMS.  "viii.  p.  244. 

For  C.  operculata  (p.  811),  substitute  : — 
C.  operculata  (Ag.,  Kutz.).  —  Ends  of    opercidata,  E.     Fresh  water.     Europe, 
frustules  undidate ;  valves  with  smooth        [Professor  Amott  regards  Stephano' 
centre,  and  close,  short  marginal  strise.    pyxis Niagar(B,Sindi^Qxh.?i^9  S.  Egyptiacus, 
KB.  p.  50,  pi.  1.  f.  1.  =  Frustulia  and    as  identical  with  C.  Asfrcea.'] 
Cymhella    operculata^    Ag. ;    Pyxidicula 


938 


SYSTEMATIC  HISTORY  OF  THE  INFXJSOEIA. 


For  C.  rectangula  (p.  811),  substitute  : — 


C.  Meneghiniana  (K.).  —  Front  view 
rectangular ;  valves  minute,  with  smooth 
centre  and  rather  coarse  marginal  striae. 

For  C.  Dallasiana  (p. 

C.  Dallasiana  (Sm.). — Frustules  with 
flat  ends ;  valves  with  biillate-rugose 
centre  and  coarse  marginal  striae.  SD. 
ii.  p.  87.  =  C.  radiata,  Bri.  TMS.  viii. 
pi.  6.  f.  11.  Brackish  water.  Europe,  ^ 
America, 

C.   minutula   (K.).  —  Frustules  with' 
flat  ends  ;  valves  with  radiating  dots  or 
striae  at  centre.    KB.  pi.  2.  f.  3.  =  C. 


KB.  p.  50,  pi.  30.  f.  68.     C.  rectangula, 
Rab  D.  p.  11.     Europe.     Fresh  water. 


813),  substitute: — 

opermlata,  SD.  i.  p.  28,  pi.  5.  f.  48.  Eu- 
rope. (Kiitzing,  however,  describes  his 
C.  minutula  as  undulate.) 

C.  Kiitzingiana  (Th.).  —  Ends  of  frus- 
tules undulate  J  valves  with  convex, 
smooth  centre,  and  long,  coarse  mar- 
ginal stri^B.  SD.  i.  p.  27,  pi.  5.  f.  47. 
Brackish  water.     Eui'ope. 


CoccoNEis  Finnica.  —  On  careful  ex- 
amination of  several  fossil  deposits  said 
by  Ehrenberg  to  contain  this  species,  we 
can  find  no  foi-m  resembling  the  figures  in 
the  ^  Microgeologie,'  excepting  Navicula 
elhptica. 

EupoDiscus  ?  Peruvianus  (Kitton, 
MS.).  — Valve  orbicular,  finely  pimc- 
tated,  with  two  smaU,  roundish  sub- 
marginal  processes,  and  a  submarginal 
series  of  close  minute  apiculi.  Peruvian 
and  Calif ornian  guanos.  We  regard  the 
genus  of  this  Diatom  as  doubtful.  The 
valve  has  some  resemblance  to  an  Au- 
liscus  ;  but  the  puncta  are  not  in  flexuose 
lines.  The  processes,  as  seen  in  front 
view,  are  short  and  subtruncate,  and 
the  circle  of  apiculi  which  connects 
them  shows  an  aflinity  to  Cerataulus. 
The  processes  of  the  one  valve  alternate 
with  those  of  the  other,  and  are  often 
visible  at  the  same  time. 

E,  ?  Grevillii  (Ralfs,  n.  sp.). — Disc  ob- 
scurely punctate,  with  (3)  clavate  intra- 
marginal  processes,  and  a  circlet  of  spines 
between  the  processes  and  the  centre. 
Monterey.  Dr.  Greville.  The  processes, 
which  are  rather  distant  from  the  mar- 
gin, resemble  those  of  Aulacodiscus,  and 
the  circlet  of  spines  that  of  Systephania ; 
but  the  absence  of  connecting  lines  re- 
moves it  from  the  former,  and  the  pre- 
sence of  processes  from  the  latter  genus. 

PoDOSiRA  ?  compressa  (West). — Frus- 
tule  geminate,  free  ? ;  polar  always  shorter 
than  equatorial  diameter  j  valves  elliptic, 
obscurely  punctate ;  puncta  scattered ; 
angulum  smooth.  Creswell  Sands, 
Druridge  Bay,  Yannouth  Sands.  West, 
TMS.  viii.  p.  150,  pi.  7.  f.  11.  (vin.  34.) 
This  form  occurs  plentifully  on  the  sands; 
the  frustules  always  occur  in  pairs.  The 
absence  of  stipes  or  any  attachment,  the 
compressed  valves,  and  the  want  of  a 


thickened  umbilicus,  render  its  position 
in  the  present  genus  doubtful. 

Epithemia  {Eunotia,  E.)  Sancti  An- 
tonii  =  E.  Beatoruni  =  Denticuta  ?  lauta 
(Bail.).  —  This  species  has  been  foimd 
by  Mr.  Kitton  in  the  Monterey-stone  and 
Richmond  deposits;  in  the  latter  they 
occur  in  filaments  of  6  and  7  fi'ustules, 
clearly  showing  that  they  are  improperly 
placed  in  the  present  genus,  and  are  pro- 
bably allied  to  Denticula. 

Navicula  hullata  (Norman,  n.  sp.). — 
"Elliptical,  extremities  slightly  pro- 
duced; striae  in  a  marginal  and  two 
central  bands ;  marginal  band  of  un- 
equal width  ;  the  blank  spaces  between 
the  granules  studded  mth  a  line  of  cir- 
cular bosses;  striae  moniliform,  14  in 
001".  Stomachs  of  Ascidians,  Shark 
Bay,  Australia  "  (Norman  in  litt.). 

N.  Sillimanorujn  (E.). — Inflated  at  the 
centre ;  apices  produced,  rounded,  and 
constricted  ;  striae  radiant,  not  reaching 
the  median  line.  EM.  pi.  2.  2.  f.  13.= 
Pimiularia  SilUmanorum,  EA.  p.  133, 
New  York  deposit.  This  species  re- 
sembles Gomplionema  geminatiim,  but  is 
distinguished  by  its  less  conspicuous 
striae  and  equal  ends ;  the  figure  in  EM. 
represents  only  a  fragment. 

N.  Cypri7im  (E.,  K.). — Small;  valves 
oblong,  slightly  contracted  into  the  very 
broad  obtuse  ends ;  central  nodule  ob- 
long ;  striae  evident.  103.  p.  99,  pi.  29. 
{.'So.  =  Fimmlaria  Ci/prinus,  EA.  pi.  1.  11. 
f.  7.     Chili.  ''^  ^ 

N.  Reinickeana  (Rab.).  —  Resembles 
N.  cuspidata  and  JV".  rostrata ;  but  the 
capitate  ends  are  more  prolonged,  and 
the  sti'ias  are  only  30  in  -001".  Rab. 
Algen  Sachs.  No.  802.     Dresden. 

Aulacodiscus  Sollittianus  (Nonnan, 
MS.). — "Disc  large,  hyaline,  %vith  six 
conspicuous  processes,  distant  from  mar- 


ADDENDA. 


939 


gin;  granules  radiating,  not  reaclaing 
the  centre,  9  in  '001"  j  smooth  round  the 
base  of  the  processes.  Deposit  from 
Nottingham,  below  Maiyland,  which 
seems  to  be  identical  with  the  Bermuda 
tripoli,  and  contains  several  forms  pecu- 
liar to  that  deposit"  (Norman  in  litt). 

A.  Barhadensis  (Ralfs,  n.s.).  —  Disc 
large,  hyaline,  very  minutel}'  punctated, 
with  small  umbilicus,  (8)  intramarginal 
roundish  processes,  and  faint  connecting 
lines.  Barbadoes  deposit.  Distinguished 
by  its  very  obscure  puncta.  The  rather 
large  processes,  when  nearly  out  of  focus, 
appear  to  have  a  central  dot. 

Teiceratium  crenatum  (Kitton,  MS.). 
— Sides  rounded,  margin  crenate ;  gra- 
nules radiating  from  the  pseudo-nodule, 
distinct  at  the  margin,  but  less  con- 
spicuous as  they  approach  the  centre.  = 
Discoplea  undulata,  EM.  pi.  33.  18.  f.  3. 
Nottingham  deposit.  The  presence  of 
the  pseudo-nodule  shows  it  to  be  an  ally 
of  T.  Brightwellii ;  but  the  nearly  orbicu- 
lar outline  and  crenate  margin  distin- 
guish it  from  that  species.     The  frag- 


ment figm'ed  by  Ehrenberg  we  have  no 
doubt  is  identical  with  this  form. 

T.  Bowerhankiana  (Ralfs).  —  Valves 
with  two  concentric  circles,  radiating 
lines  between  the  circles,  distinctly  punc- 
tated angles,  and  blank  or  indistinctly 
punctated  centre.  Barbadoes  deposit. 
The  large  valve  has  nearly  straight  sides, 
and  obtuse  angles;  it  is  divided  into 
three  parts  by  two  suture-like  circles, 
the  outer  one  with  a  border  of  bead-like 
dots,  which  are  most  evident  nearest  the 
sides ;  the  lines  between  the  circles  are 
abbreviated,  only  one  on  each  side  reach- 
ing the  inner  circle. 

Grasped ODisc us  Barhadensis  (Ralfs, 
n.  s.). — ^Border  very  broad,  its  diameter 
greater  than  that  of  the  centre ;  cellules 
of  centre  very  minute,  those  of  border 
larger  and  arranged  in  cun^ed,  decussat- 
ing lines.  Barbadoes  deposit.  Disc 
about  the  size  of  C.  Coscinodiscus,  but 
with  a  much  smaller  centre.  It  differs 
from  both  that  species  and  C.  microdiscus 
in  having  the  cellules  of  the  border  in 
cm'ved  series. 


Substitute  the  following  descriptions  for  the  notices  of  Craspedodiscus  Stella 
and  C.  FranUini  at  p.  832  :— 


C.  ?  Stella (E.). — Valves  hemispherical, 
with  a  very  broad,  smooth,  obsoletely 
radiated  limb,  and  a  small,  finely  cellu- 
lose centre,  having  an  irregular  margin  ; 
rays  12,  irregular.  EB.  1855,  p.  238 ;  E 
M.  pi.  35  B.  B.  4.  f.  11.  North  America. 
On  account  of  its  rays,  this  form  may  be 
the  type  of  a  new  genus ;  but  they  were 
distinct  only  in  a  single  specimen,  whilst 
in  the  greater  number  scarcely  a  trace  of 


them  could  be  detected.     It  approaches 
to  the  characters  of  Symbolophora. 

C.  Franklini  (E.). — Disc  tm-gid,  with 
a  deciduous,  broad,  hyaline,  smooth 
marginal  limb,  and  a  very  tine  punctated 
(yellowish)  centre,  having  an  irregular 
margin ;  centre  and  limb  of  nearlv  the 
same  diameter,  ERBA.  1853,  p."  626; 
EM.  pi.  35  A.  23.  f.  6.  Assistance  Bay. 
Akin  to  Coscinodiscus  disciger. 


To  C.  semiplanus  (Bri.),  add  : — 

This  Diatom,  which  is  not  uncommon 
in  the  Barbadoes  deposit,  is  no  doubt 
incorrectly  placed  in  this  genus.  In  our 
opinion  it  is  closely  allied  to  Astero- 
lampra,  and  should  either  be  united  to 
that  genus,  or  a  new  genus  formed  to 

To  C.  marginatus  (Bri.),  add  : — 

We  consider  that  this  Diatom  also  is 
wrono^ly  referred  to  Craspedodiscus,  and, 
notwithstanding  its  large  punctated 
centre,  is  really  more  allied  to  Astero- 
lampra, — its  marginal  compartments, 
however,  being  extremely  minute.  In 
the  Barbadoes  deposit  we  find  discs 
sometimes  (as  in  Asterolampra)  without 
any  umbilical  cellides,  and  sometimes 
with  a  larffe  cellulose  centre,  and  these 


include  this  and  other  allied  discs  asso- 
ciated together  in  the  deposit.  Mr. 
Brightwell's  specimen  must  have  been 
imperfect,  since  we  find  the  radiating 
lines  invariably  correspond  in  nmnber 
with  the  marginal  compartments. 


extremes  so  connected  by  intermediate 
states  as  to  make  it  doubtful  whether 
the  cellulose  centre  is  available  even 
as  a  specific  distinction.  We  hope  Dr. 
GreviUe,  who  has  paid  much  attention 
to  these  forms,  waU  soon  publish  a 
monograph  of  them  in  continuation  of 
his  former  admirable  paper  on  Astero- 
lampra. 


940 


SYSTEMATIC  HISTOEY  OF  THE  IN-FUSOEIA. 


For  Craspedodiscus  coj'onatus,  substitute  the  following  : — 

Genus  BRIGHTWELLIA  (Ealfs,  n.  g.).— Disc  with  a  large  granulated 
centre,  separated  from  a  broad  punctated  limb  bj  a  circlet  of  oblong  cellules. 

"VVe  have  constituted  this  genus  to  receive  a  beautiful  Diatom  placed  by  Mr. 
Brightwell  in  Craspedodiscus,  but  which  differs  so  greatly  from  other  Diatoms 
that  we  believe  it  should  form  the  type  of  a  new  one,  which,  with  much  plea- 
sure, we  dedicate  to  the  author  of  the  excellent  monographs  of  Triceratium 
and  the  Chgetocerege. 


Brightwellia  coronata  (Bri.,  Ralfs). 
—  Central  portion  of  valve  with  an 
irregular  blank  umbilicus  and  radiating 
series  of  granules,  which  are  closer  and 
in  curved  lines  near  the  circlet  of  cellules. 
=  Craspedodiscus  coro7iatus,  Bri  JMS. 
viii.  p.  95,  pi.  5.  f.  6.  Barbadoes  deposit. 
This  species  is  very  variable  in  size.  In 
a  dry  state  it  is  of  a  purplish  or  brown 
colour,  but  in  balsam  hyaline;  the  centre 
has  the  gramdes  irregular  near  the  imi- 


bilicus,  and  interrupted  by  blank  rays; 
but  near  the  circlet  of  cellules  they  be- 
come more  regular,  and  form  curved, 
moniliform  lines.  The  broad  limb  is 
usually  brownish  when  dry,  and  marked 
by  numerous  radiating  lines,  similar  to 
those  of  Coscinodiseus  conci?i)ius,  and 
have  in  the  intervals  extremely  minute 
obliquely  arranged  granules.  The  radi- 
ating lines,  although  conspicuous  in  the 
dry  statC;  nearly  disappear  in  balsam. 


After  Cymatopleuba  Ovtwi  (p.  793),  insert : — 


C.  multifasciata  (Kiitz.).  —  Valves 
linear,  with  acutely  cuneate  apices,  and 
very  fine  transverse  strise.  =  Surirella 
multifasciata,  KB.  p.  60,  pi.  3.  f.  47. 
Europe. 


C.  therynaUs  (Kiitz.).  —  Slightly  pan- 
duriform,  otherwise  as  in  C.  multifasciata. 
=  Surirella  thermalisj  KB.  p.  60,  pi.  3. 
f.  46.     Europe. 


Genus  CYLINDEOTHECA  (Rab.).— Frustules  exactly  cylindrical,  with 
percurrent  spires,  and  imbedded  in  an  amorphous,  gelatinous  mucus. 

CYX,iNi)R0THECA(xers^e«5er^en(Rab.).  I  (rarely  one  or  three)  spires.    Rab.  Algen 
— ^Frustules  lanceolate,  acute,  with  two  |  Sachsens,  No.  801.     Dresden. 


Note. — Mr.  Ralfs  originally  proposed  to  introduce  a  family  Synedreae,  as 
mentioned  in  p.  758,  but  subsequently  transferred  the  genera  to  the  family 
Surirelleae,  the  genera  in  which  he  distributes  thus : — 

*  Frustules  hacillar  ;  valves  keeled — Nitzschie^. 
Genera.  Nitzschia,  Ceratoneis,  Amphipleura,  Bacillaria,  and  Homoeocladia. 

2*  Frustules  hacillar;  valves  scarcely  broader  than  front  view,  not  heeled — 

Synedre^. 

Genera.  Synedra,  Desmogonium,  Dimeregramma,  and  Staurosii-a. 


3*  Frustules  not  hacillar;  valves  mostly  hroacler  than  front  view,  not  heeled — 

Surirelle^. 

Genera.  Rhaphoneis,  Tryblionella,  Cymatopleura,  Surirella,  Campylodiscus, 
and  Calodiscus. 


INDEX 


TO 


THE  FIGURES  ILLUSTRATING  THE  DIATOJMACEiE. 


Plate  Page 

AcHNANTHES  breidpes x.  199-202 873 

exilis    Yii.  44 874 

longipes vn.  42 873 

subsessilis    yii.  43 874 

AcHNAXTHiDiuM  coarctatum  vn.  41 873 

delicatiilum xiv.  16 872 

microcephalum   xiv.  15 872 

trinode vni.  9 872 

AcTixocYCLUS  Ralfsii v.  84    835 

AcTiNOGOXiuivi  septenarium    .....  v.  55    813 

AcTiNOPTYCHUs  ?  hexapterus xi.  31  840 

Jupiter XI.  28 840 

senariiis    ix.  132 839 

Tindulatus    v.  88    839 

Amphicampa  mirabilis iv.  5 765 

Amphipentas  alternans    xi.  32 858 

flexuosa    yi.  22 «,  6    858 

Amphipleuha  inflexa iy.  31 783 

pellucida iy.  30^  ix.  140j  xni.  1 . .  783 

rigida   xiii.  2 783 

Amphiprora  alata    xin.  5,  6,  7 921 

constricta     xn.  1    922 

AisiPHiTETRAS  antedilaviana    xi.  21,  22 858 

omata viii.  16    858 

Amphora  angularis  Yn.  50 881 

cymbifera     yii.  54 882 

gracilis xn.  26 884 

byalina     Yn.  58 884 

litoralis    vu.  52 881 

Lybica xn.  38 883 

marina Yn.  59 884 

membranacea Yn.  51 881 

monilifera    Yn.  79 882 

navicularis  xn.  37 884 

ovalis    Yn.  56j  IX.  153 883 

spectabilis    Yn.  57 884 

Anaulus  scalaris  Yin.  37    859 

Arachnoidiscus  omatus xy.  18-21    842 

AsTERioNELLA  formosa    lY.  17   779 

Ralfsii IY.  18   779 

AsTEROLAMPRA  Marylandica xi.  33   836 

ASTEROMPHALUS  Arachne    y.  66    837 

Brookeii v.  79    837 


942  IN-DEX  TO  THE  FIGUEES  OF  DIATOMACE^. 

Plate  Page 

AsTEROMPHALiJs  centi'aster viu.  14    838 

Darwinii v.  86    837 

elegans v.  87    837 

heptactis vm.  21     838 

Hookerii xi.  34 836 

Attheya  decora    vin.  35    863 

AuLACODiscus  Beeveriae vi.  5 844 

Kittoni     VIII.  24    844 

Oreganus vi.  4 845 

pulcher     vm.  28    845 

AuLiscus  pruinosus vi.  1 845 

sculptus    VI.  3 845 

Bacillaeia  cursoria iv.  20 784 

paradoxa iv.  19  j  ix.  166, 167    ....   784 

Bacteria  STRUM  furcatum   vi.  26 863 

Wallicliii vi.  27  863 

Berkeleya  Adriatica xiv.  34,  35 926 

Biblarium  CasteUiim  (EM.  33.  2. 1)  iv.  44   806 

BiDDULPHiA  Indica  vi.  12    849 

Macdonaldii     vm.  23    849 

obtusa xm.  30-32 848 

pulchella n.  46-50 848 

Tuomeyi vi.  10   848 

Calodiscus  superbus    vm.  50    % 802 

Campylodiscus  Clypeus xvii.  516-518 801 

Ebrenbergii , xii.  12,  13,  22,  23 802 

flexuosa    xn.  11 802 

Hibeinicus  iv.  38   799 

parvulus xv.  22,  23    801 

spiralis iv.  39    802 

Cerataulus  Isevis    vi.  7 847 

turgidus    VI.  8 846 

Ceratoneis  Closterium   xii.  59 783 

longissima    iv.  23  783 

spiralis xm.  9 783 

Cil5;toceros  boreale    vi.  25  861 

Wighamiii vi.  24  862 

Cladogramma  Califomicum vm.  11     814 

Climacosphenia  moniligera xi.  45,  46     772 

CoccoNEis  Americana xn.  48 871 

distans vn.  38 870 

excentrica    vii.  40 871 

Finnica xii.  41 870 

Oceanica xn.  42 868 

Placentula vii.  36 868 

pseudo-marginata vn.  39 871 

Scutellum    ix.  162, 163 869 

transversalis     vn.  37 869 

CoccoNEMA  Boeckii \t:i.  48 878 

Cistiila X.  196-198 878 

cymbiforme xn.  46 878 

^bbum    xni.lO     878 

lanceolatum     x.  194, 195 877 

paniim     vn.  47 878 

CoLLETONEMA  Amphioxys xn.  55-57    927 

eximium tui.  43    926 

neglectiim    vm.  47    926 

CosciNODiscus  concinnus    v.  89    828 

excavatus     -vmi.  26    829 

nitidus vm.  18     831 

ovalis V.  78 831 


INDEX  TO  THE  FIGUKES  OF  DIATOMACEJE.  943 

Plate  Page 

CosciNOBiscus  radiatus    xi.  39,  40    830 

stellaris    v.  83    828 

Craspedodiscus  Coscinodiscus v.  80    832 

elegans xi.  38 832 

Cyceotella  Atlantica xv.  3    812 

atmospherica  xv.  1,  2    812 

operculata    v.  53     811 

punctata vni.  13     813 

rectangiila    v.  54     811 

Scotica XIV.  17 811 

Sinensis    xv.  4    812 

Cymatopleura  eUiptica ix.  149 ;  xvi.  7,  8 793 

Solea    IX.  155 ;  xvi.  9   793 

Cymbella  Arcus  vii.  78 875 

cuspidata vn.  45 876 

Ehrenbergii vn.  46;  ix.  154 875 

gastroides    xiv.  18-20 877 

Helvetica xiv.  24-28 876 

Cymbosira  Agardhii     xiv.  14 875 

Denticula 'elegans xni.  4 773 

Desmogonium  Guianense     xv.  13 790 

DiADESMis  confervacea xiv.  32,  33 923 

Isevis     XII.  40 923 

DiATOMA  Ehrenbergii    iv.  15   779 

elongatiim   iv.  14;  ix.  169 779 

hyalinum iv.  16   778 

mesodon ix.  170 778 

vulgare     iv,  13;  ix.  168    778 

DiATOMELLA  Balfouriana iv.  51   810 

DiCKiEiA  ulvoides xv.  31 925 

DiCLADiA  Capreolus vi.  28  863 

Dictyocha  Fibula    xv.  34 935 

Speculum     xii.  62,  63  936 

trifenestra    xv.  35 935 

DiCTYOLAiMPRA  Stella V.  58     813 

DiisiEREGRAiMMA  distans   IV.  34  790 

Harrisonii    vm.  6 790 

nanum iv.  33  790 

pinnatum vm.  4 791 

sinuatum iv.  12   790 

TabeUaria    iv.  35   790 

DiscosiRA  sulcata v.  68    822 

DisiPHONiA     australis  =  DiatomeUa 

Balfom-iana iv.  52   810 

DoNKiNiA  carinata     vm.  49    921 

Encyonema  prostratum    vn.  49 ;  xiv.  22 879 

Endictya  oceanica    v.  70     831 

Epithemia  alpestris xin.  8 760 

Argus  XV.  11 759 

gibba    XII.  27 759 

gi-anulata. ix.  165 761 

Librile xii.  24,  25    761 

longicomis xv.  6-9    760 

Musculus xin.  18    760 

Porcellus xm.  12    761 

tiu'gida IV.  1 ;  IX.  156-161 ;  xi.  1-8  761 

Westermanni iv.  2 ;  ix.  *  157   760 

EuCAMPiA  Zodiacus n.  43    937 

Eunotia  pentaglypbis iv.  3 764 

quinaria   .  .  ."^ xii.  39 764 

triodon, iv.  4:  ix.  164. 763 


944  rsTDEX  TO  the  figuees  of  DIATOMACE-E, 

Plate 
EuxoTOGRAMMA  tri-  quiiique-  sep- 

tem-  et  novemloculata  ....  vin.  30    860 

EuoDiA  gibba viii.  22    852 

EuPLEUMA  ocellata vni.  2 809 

pulchella vin.  8 809 

EupoDiscus  Argus    vi.  2 ;  xi.  41,  42 843 

Fragilaeia  capucina   ix.  173-175  j  xiv.  1,  2  .  .   776 

virescens ix.  176 777 

Gephyria  incurvata v.  50    809 

media   v.  49     809 

Gomphogramma  rupestre    rv.  46   806 

GoMPHONEMA  acuminatum xiii.  23    887 

apiculatum xn.  28,  53   889 

constrictum x.  187-190 887 

coronatum   xiv.  36     887 

cm-vatum xi.  9-12 ;  xni.  11 888 

geminatum yii.  60 887 

minutissimum xi.  17    891 

Vibrio xii.  35 890 

GoNiOTHECiuM  creuatiim xv.  10 • 864 

Odontella vi.  29  864 

Grammatophora  gibba   xi.  48,  49    808 

hamulifera   xin.  22 808 

marina iv.  47 ;  xi.  52,  53 808 

serpentina    iv.  48  808 

Grammonema  Jurgensii xv.  24,  25    778 

Halionyx  undenarius   v.  82     833 

Heliopelta  Metii xi.  35 841 

Hemiaulus  antarcticus     xi.  54 851 

Hemidiscus  cuneiformis vi.  14   853 

Hercotheca  mammillaris  vii.  35 867 

Heterostephania  Rotkii v.  85     833 

HiMANTiDiuiM  Guianense xii.  54 766 

monodon xn.  29  -,  xv.  16,  17    765 

Papilio XII.  45.  49-52 766 

pectinale iv.  6 ;  ix.  171-176 765 

Soleirolii xiv.  13     765 

HoMCEOCiiADiA  filifomiis IV.  25 785 

Martiana iv.  24;  xiv.  47-49 784 

monilifomiis    xiv.  45,  46 785 

pumila XIV.  37,  38 785 

sigmoidea     iv.  26  785 

Hyalodiscus  subtilis    v.  60    815 

Hyalosira  delicatula   iv.  42  804 

obtusangula xiv.  29     804 

rectangula    xiv.  23     804 

Hydrosera  compressa vi.  8 852 

triquetra vi.  13  852 

IsTHisnA  enervis x.  183 851 

LiCMOPHORA  divisa  xni.  16    772 

flabellata iv.  9;  x.  191-193 771 

LiosTEPHANiA  magnifica v.  56    813 

.      Eotula V.  57    813 

Liparogyra  dentroteres v.  72    823 

LiTHODESMiuM  undulatum ii.  41,  42 937 

Lysicyclia  Vogelii  viii.  39    815 

Mastogloia  Danseii xv.  30 924 

Mastogonia  Actinoptychus    v.  59    814 

Melosira  arenaria    viii.  17    819 

coarctata xi.  20  &  27 818 

Dickieii    xv.  29 820 


INDEX  TO  THE  FIGUKES  OF  DIATOMACEiE.  945 

Plate  Page 

Melosiha  Horologium v.  62 819 

Italica  XI.  29 ;  XV.  33    818 

Jurgeusii v.  03     817 

mouiliformis    v.  71     817 

Nageli x v.  26,  27    822 

uunimidoides v.  64 :  xi.  14 816 

oriclialcea v.  6o  j  viii,  33    818 

Eoseana   v.  67     818 

subflexilis     V.  63     817 

sulcata IX.  131 ;  xi.  26 819 

varians iv.  32 ;  ix.  *  131 ;  xv.  32   817 

Meridion  circulare    ix.  177-179 ;  xiu.  21    . .   767 

Mesocexa  heptagona    xn.  71 936 

MiCEOMEGA  Agardhii    x.  208 933 

bombvciniiiii    xiv.  43, 44 933 

paUidum xiv.  39-42 934 

MiCROTHECA  octoceras vin.  31    937 

Navicula  affinis    xii.  32 902 

Ampliirliyuclius xii.  6    901 

Ampliisb£8na   vii.  72 ;  ix.  141 899 

borealis     vn.  74 907 

cardinalis xii.  72 896 

Chilensis xii.  33 907 

Cluthensis    ^ai.  73 909 

ciispidata xn.  5   905 

didyma vii.  61 ;  xv.  12 893 

Esox xii.  43 896 

Heimedyi yn.  69 898 

Hitcbcockii vii.  62 894 

latissima vn.  70 903 

major    vn.  65 ;  xn.  15,  31 ;  xvi.  1-6  896 

maxima    vu.  75 909 

nodosa ix.  143 894 

producta vn.  66 902 

rbombica vn.  71 903 

rbvncbocepbala vn.  68 900 

Tabellaria    xn.  21 896 

tseuiata xv.  15 900 

tumida vn.  55 910 

viridis ix.  133-136 907 

Nitzschia  Brigbtwellii    vni.  7 780 

scalaris iv.  22  781 

Sigma IV.  21  781 

sigmoidea     ix.  148 781 

?  valens    xn.  44 782 

Odontidium  hyemale    ix.  172 ;  xin.  24,  25 775 

ODONTODiscrs"^eccentricus    v.  90    832 

Omphalopelta  areolata vni.  15    841 

Omphalotheca  bispida  viii.  44    865 

Oncosphenia  ?  CarpatMca viii.  1 768 

Periptera  cblamidopbora vni.  25    865 

tetracladia    \^.  30 865 

Peristephania  Eiitycha v.  73    824 

Perithyra  denaria  vni.  19    842 

Plagiogramma  pulcbellum iv.  32 774 

PLEURODESMirM  Brebissonil   ^t:.  23  860 

Pleurosigma  acuminatimi ix.  146     919 

Balticum vin.  33 ;  ix.  144    917 

Fasciola    xn.  60,  61   916 

formosum     ^ vui.  32    917 

Hippocampus ix.  145 919 


946  INDEX  TO  THE  FIGURES  OF  DIATOM  A  CE.i;. 

Plate  Page 

Pleurosiphonia  affinis    viii.  45    915 

PoDOCYSTis  Adriatica iv.  10 772 

PoDODiscus  Jamaicensis xiii.  28    815 

■  PoDOSLRA  ?  compressa viii.  34    815 

hormoides    ii.  45    815 

PoDOsrRA  Montagnei    v,  61    815 

PoDOSPHENiA  cuneata xiii.  136 769 

Ehrenbergii iv.  7 ;  xin.  14    769 

gracilis x.  186 769 

hyalina     xiii.  13    769 

PoRPEiA  quadriceps Yi.  6 850 

Pyxidicula  Adriatica xiii.  33    825 

globata XVII.  506^09 825 

Rhabdonema  Adriaticum    xiii.  27    805 

arcuatum ix.  180-182j  x.203,  204. .  804 

Crozieri    iv.  43 805 

minutum iv.  41   804 

mirificum ^^II.  12    805 

Rhaphoneis  Ampliiceros     xiv.  21     791 

Rhipidophoea  Menegliiniana     ....  xiii.  19    771 

Nubecula xiii.  17    770 

paradoxa iv.  8 770 

tenella xin.  15    770 

Rhizonotia  Melo viii.  41    886 

Rhizosolenia  Calyptra   vii.  31 866 

robusta viii.  42    866 

setigera    vii.  33 865 

stjdifonnis    \^t.  32 865 

Sceptroneis  Caduceus    iv.  11  772 

ScHizoNEMA  Dillwj'iiii VIII.  40    928 

GreviUii  viii.  38    928 

Hoffinannii x.  207 928 

Sphenella  angustata xrv.  30     886 

obtusata   xiv.  31     886 

Sphenosira  Catena xi.  30 892 

Staurogeaimma  Persicum  viii.  36    915 

Staueoneis  acuta vii.  76 914 

Crucicula ^^i.  64 912 

dilatata     xii.  16 911 

Isostauron   xii.  73 914 

Legunien vn.  67 911 

obliqua     vii.  63 911 

Phceuicenterou    ix.  139 ;  xii.  17,  18 913 

pbyllodes xn.  7-9   912 

platystoma ix.  142 912 

pulclieUa VII.  77 914 

scalaris xii.  10,  14,  30 915 

Staurosira  construens    xv.  5    791 

Stephanodiscus  iEgyptiacus v.  69    824 

Stephanogonia  polygona   v.  77    814 

Stephanopyxis  ferox v.  75    826 

Tunis  V.  74    826 

Stigmaphora  rostrata viii.  48    923 

Striatella  unipunctata iv.  40 ., . .  .   803 

Stylobiblium  Clypeus    rv.  45  805 

SuRiRELLA  biseriata xvi.  20-26 794 

constricta xiii.  3 794 

Craticula xii.  19,  20   794 

Gemma    xn.  2-4   796 

splendida ix.  150-152     795 

striatula  . , ix.  137,  138    796 


INDEX  TO  THE  FIGURES  OF  DIATOilACE^.  947 

Plate  Page 

Symbolophoea  Trinitatis    xi.  36  833 

Syncyclia  Salpa  vii.  53  j  x.  206 879 

Synedra  Arcus iv.  27  789 

capitata    iv.  29 ;  x.  185  * 788 

fulgens XIII.  20    789 

Gallionii xii.  34,  36  788 

limaris x.  185 785 

pulcliella IV.  28  786 

robusta vin.  3 789 

subtilis IX.  147 786 

Ulna X.  184 788 

Syringidium  Americanmn vii.  34 866 

bicorne \^II.  20    866 

Systephania  Corona    v.  81    832 

Tabellaria  flocculosa xiii.  29    807 

yenti-icosa    xiii.  26 807 

Terpsinoe  musica xi.  47  859 

Tessella  interrupta viii.  5 804 

Tetracyclus  laciistris xi.  24,  25  j  viii.  10    ....  806 

ToxoNiDEA  undiilata Tin.  46    920 

Triceratiuivi  alternans     vi.  21  854 

castellatum viii.  29    854 

contortiim    vi.  18 853 

exiguiim vi.  16 857 

Favus  XI.  43,  44    855 

punctatiim  \t:.  20 856 

Bolenoceros vi.  15 856 

spinosiim VI.  19  853 

trisnlcimi viii.  27    854 

venosum vi.  17 854 

Tryblionella  acuminata    rv.  37  792 

gracilis iv.  S6  792 

Xanthiopyxis  oblonga     v.  76    827 

Zygoceros  Siu'irella xi.  50,  51    850 

Mobiliensia vi.  11  850 


3p  2 


949 


DESCRIPTION  OF  THE  ENGRAVINGS. 


PLATE  I.  (Desmids). 


Figures  1  to  14.  Cosmarium  margaritiferum,  &c.,  under  different  stages  of  develop- 
ment: 1,2.  Frond,  enclosing  "vesicles  "filled  with  moving  granules;  3.  Supposed  early  state 
of  moving  granules ;  4.  Early  stage  of  self-fission ;  5.  Fission-products  escaping  the  enclosing 
wall  of  parent  cell ;  6.  Separation  completed ;  7.  Sporangium  still  connected  with  parent 
frond ;  8.  Same  with  mammilliform  spines ;  9.  Sporangium  further  developed  ;  10, 11. 
Supposed  mature  sporangia ;  12.  Same,  broken  and  empty ;  13, 14.  Young  supposed 
products  of  sporangial  contents :  all  after  Mrs.  Thomas,  TM.  1855.  [We  are  disposed  to 
think  that  one  or  two  other  species  besides  Cosmarium  margaritiferum  are  here  confounded. 
4,  we  suggest,  may  possibly  be  C,  caelatum  or  C.  cristatum,  showing  nascent  segments ; 
7,  C.  Broomei,  the  empty  frond  to  the  right  showing  a  segment  not  yet  fully  developed ; 
8  and  9  appear  to  us  as  probably  more  likely  to  represent  the  conjugated  state  and  sporan- 
gium of  C.  bioctdatum,  of  which  figs.  10,  11,  12,  may  represent  the  ultimately  extruded 
inner  membrane,  while  figs.  13  and  14  may  truly  be  the  young  fronds  developed  from  their 
contents,  and  which  have  not  yet  commenced  vegetative  self-division.]  15-17.  Sphaero- 
zosma  vertebratum  (Ealfs) :  15.  A  portion  of  a  filament  seen  in  f.  v.  X  200 ;  16.  tr.  v. 
X400 ;  17.  s.  V.  X400.  18, 19.  Micrasterias  papillifera  (Breb.) :  18.  f.  v.  X 100 ;  19.  Spo- 
rangium x200.  20.  M.  rotata  (Ealfs),  f.  v.  xlOO.  SI.  M.  radiosa  (Ag.),  f.  v.  xlOO. 
22.  M.  Crux-MeUtensis  (Ealfs),  f.  v.  xlOO.  23-25.  Euastrum  Didelta  (Ealfs):  23.  f.  v. 
with  endoclarome ;  24.  e.  f.  in  f.  v. ;  25.  tr.  v. :  all  x200.  26,  E.  rostratum  (Ealfs),  f.  v. 
X400.  27, 28.  Xanthidium  armatum  (Breb.) :  27.  f.  v. ;  28.  s.  v. :  both  x200.  29,  30. 
Arthrodesmus  octocornis  (Elu\):  29.  var.  j3,  f.  v. ;  30.  var.  a,  f.  v. :  both  x400.  31-34. 
Staurastrum  cuspidatum  (Breb.) :  31.  f.  v. ;  32.  showing  the  nascent  segments ;  33.  tr.  v.  ; 
34.  e.  v.:  all  x400.  35,36.  Ankistrodesmus  falcatus  (Ealfs),  x400.  37-39.  Sceno- 
desmus  obtusus  (Meyen),  after  Nageli,  showing  segmentation  of  the  cell-contents,  x300. 
40-42.  S.  caudatus,  after  Nageli,  x300.  43.  Same,  segmentation  of  cell-contents,  x400. 
44,45.  A  few  marginal  cells  of  "  Pediastrum  Seleneea  (Kg.)"  =  P.  pertusum  (?),  after 
Nageli,  x300.  46-48.  P.  (Anomopedium)  integi-um  (Nag.):  46.  xloO;  47.  x400; 
48.  s.  V.  x400.  49-51.  Coelastrum  sphajricum  (Nag.):  49.  x200;  50,  51.  X300. 
52.  Pediastrum  Ehi-enbergii  (Braun),  after  Braun,  x400.  53.  P.  Selenaea  (Kg.)  [non 
Ealfs,  =  P.  pertusum],  after  Nageli,  Xl50.  54,  55.  Coelastrum  cubicum  (Nag.),  after 
Nageli,  x300.  56-58.  Sorastrum  spinulosum  (Nag.):  56.  x300;  57,  58.  x600. 
59-61.  Pediastrum  Boryanum,  var.  brevicornis,  after  Braun :  59.  Two  marginal  cells, 
one  empty,  the  other  discharging  the  original  inner  membrane  closely  investing  the  micro- 
gonidia;  60.  The  same  half  an  hour  afterwards,  coiisiderably  dilated,  the  microgonidia 
each  with  a  pointed  hyaline  beak,  and  at  first  slowly  moving  ;  61.  Microgonidia, 
eventually  emitted,  swimming  freely:  all  x300.  62.  P.  granulatum  (Kg.).  63.  Brood 
of  macrogonidia  emerged  from  shell  of  old  frond,  x400.  64.  A  few  marginal  cells  of  an 
old  frond,  some  empty,  the  cell-contents  of  others  undergoing  previous  segmentation,  and 
one  discharging  the  mner  membrane  investing  the  brood  of  macrogonidia  (Bi'aun),  x400, 
65.  Same  as  63,  seen  from  the  edge,  X  400.  66.  Same,  seen  in  f.  v.,  the  cells  now  slightly 
emarginate,  x400.  67.  Same,  four  hours  after  the  macrogonidia  have  ceased  to  move,  the 
marginal  cells  now  drawn  out  into  horns,  but  not  yet  having  assumed  their  proper  form» 
and  all  exhibiting  spaces  between,  not  yet  having  become  closely  applied  to  each  other, 
X  400.  68,  69.  P.  Boryanum :  microgonidia  treated  with  tincture  of  iodine  and  stJ- 
phuric  acid,  showing  the  vibratile  cilia,  the  slightly  retracted  contents,  and  a  nucleus, 
X  500.     (Figs.  63-69  after  Braun. ) 

PLATE  II.  (Desmids). 

Figures  1  &/  5.  Closterium  Leibleinii  (Kg.),  x200 :  1.  A  frond  filled  with  endochrome, 
and  an  empty  one  lying  across  it  (tlie  latter  shows  the  central  sutiu-e) ;  5.  Sporangium  lying 
between  the  conjugated,  and  now  empty  fronds.  2  &  6.  Closterium  sti'iolatum  (Ehr.), 
X  100 :  2.  A  frond  with  endochrome,  showing  the  longitudinal  fillets  and  the  single  row  of 
large  granules;  6.  Two  empty  conjugated  fronds,^  showing  the  stri«  and  the  orbicidar 


950  DESCRIPTION  OF  THE  ENGRAVINGS. 

sporangium  lying  between  them,  enveloped  in  mucus.  3.  Staurastrum  (Desmidium,  Ehr.) 
eustephanum,  e,  V.  4.  Spii'ota^nia  condensata  (Breb.),  x200:  the  frond  is  seen  with  its 
spiral  band  of  endochi'ome,  and  surrounded  by  a  mucous  hyaline  sheath.  7.  Staui'astrum 
(Desmidium,  E.)senarimn.  8  &  11.  Docidimn  Ehrenbergii  (Ralfs),  X  100:  8.  Conjugating 
fronds,  the  sporangium  in  an  early  stage  of  development ;  11  shows  the  process  of  develop- 
ment by  fission,  the  young  segments  partially  gi-own.  9.  Docidium  clavatum  (Kg.),  X 100. 
10  &  30.  Euastrum  pectinatum  (Breb.),  x200:  10.  A  single  frond;  30.  The  spinous 
sporangium,  the  empty  segments  adjacent.  12,  13.  Tetmemorus  Brebissonii  (Ealfs),  X 
200 :  12.  f.  V. ;  13.  s.  v.  14,  15.  Penium  margaritaceum  (Breb.),  x200 :  14.  f.  v.  var.  a ; 
15.  s.  V.  of  two  empty  fronds,  var.  y,  the  sporangium  between  them.  16,  17.  Staurastrum 
alternans  (Breb.),  x400:  16.  f.  v. ;  17.  e.  v.  18  &  23.  Xanthidium  cristatum  (Breb.), 
X400:  18.  f.  v.;  23.  e.  v.  19  &  36.  Scenodesmus  quadricauda  (Ealfs),  x400:  19.  A 
frond  of  two  cells ;  36.  one  of  four  cells.  20,  21,  24,  25  &  31.  Staurastrimi  polymor- 
phum  (Breb.),  x400;  20.  e.v.  (of  five-rayed  var.);  21  &  31.  f.v. ;  24.  A  frond  multi- 
plying by  self-division ;  25.  Sporangium  with  its  fm-cate  spines,  and  around  it  the  empty 
and  previously  conjugated  fronds.  22.  Micrasterias  denticulata  (Breb.),  X 100,  sporan- 
gium of.  26.  Cosmarium  caelatum  (Ralfs),  x300:  front  view  of  frond  midtiplying  by 
self-division,  the  young  segments  partially  grown  and  their  sm-face  still  smooth.  27.  Pe- 
diastrum  tetras  (Ralfs),  x400,  f.v.  of  a  frond.  28,  29.  Tetrachastrum  oscitans  (Dixon), 
XlOO:  28.  f.  v.;  29.  tr.  v.  of  e.  f.  32  &  35.  Hyalotheca  dissiliens  (Breb.):  32.  x200, 
tr.  V.  with  investing  hyaline  gelatinous  sheath;  35.  X400,  f.v.,  also  showing  the  sheath. 
33,34.  Cosmarium  midulatum  (Corda),  x400:  33.  f.  v. ;  34.  Sporangivun  with  the 
empty  fronds.  37  &  40.  Desmidium  quadrangulatum  (Ralfs):  37.  x200,  f.  v.  of  fila- 
ment; 40.  X300,  tr.  V.  38,39.  Didymoprivun  Borreri  (Ralfs),  x400:  38.  tr.  v. ;  39. 
Portion  of  a  filament,  f.  v.  Diatoms  : — 41,  42.  Lithodesmium  undulatum  ;  43.  Eucampia 
Zodiacus.  Desmid  : — 44.  Micrasterias  Americana.  Diatoms  : — 45.  Podosira  monilifor- 
mis attached  to  Polysiphonia ;  46,  47,  49,  50.  Biddulphia  pulchella;  48.  Denticella 
Biddulphia. 

PLATE  III.  (Desmids). 

Figure  1.  Gonatozygon  Ealfsii  (De  Bary),  three  joints  of,  x300;  2.  Same,  conju- 
gated, showing  sporangium,  x300.  3.  Genicularia  spirotsenia  (De  Bary),  single  joint  of, 
X 150  (vide  De  Bary,  op.  cit.  iv.  1.  p.  717),  x300.  4.  Leptocystinema  Kinahani  (Archer), 
X200,  showing  front  and  side  views  of  the  band  of  endocln'ome,  and  two  joints  with 
nascent  halves.  5.  Aptogonum  Baileyi  (Ralfs),  x400;  6.  Same,  e.  v.  7.  Desmidium 
Aptogonum  (Breb.),  portion  of  a  filament,  x400;  8.  Same,  e.v.  x400.  9.  Spondjlosium 
depressum  (Breb.),  x300:  five  joints,  one  dividing.  10.  S.  pulchellum  (Archer),  x450: 
five  joiuts  of  a  filament.  11.  Euastrmm  oblongum  (Ralfs),  x200.  12.  E.  insigne  (Hass.), 
X200.  13.  E.  binale  (Ralfs),  X  400.  14.  Cosmarium  pyramidatum  (Breb.),  X  300; 
15.  Same,  e.  v.  x300.  16.  C.  cylindi-icum  (Ralfs),  x300;  17.  Same,  e.  v.  X300.  18. 
Staurastrum  avicula  (Breb.),  X3(X);  19.  Same,  e.v.  x300.  20.  S.  teliferum  (Ralfs), 
X300;  21.  Same,  e.v.  x300,  22.  S.  spongiosum  (Breb.),  x300;  23.  Same,  e.v.  x300. 
24.  S.  quadrangidare  (Breb.),  x300;  25.  Same,  e.  v.  26.  S.  globulatum  (Breb.); 
27.  Same,  e.v.  28.  S.gracde  (RaKs),  x300;  29.  Same,  e.v.  x300.  30.  S.  vestitum 
(Ralfs),  x300;  31.  Same,  tr.  v.  x300.  32.  S.  fiu-cigerum  (Breb.),  X200;  33.  Same,  e.v. 
X200.  34.  S.  margaritaceum  (Menegh.),  X  300 ;  35.  Same,  e.  v.  X  300.  36.  Arthro- 
desmus  Incus  (Hass.),  X  400.  37.  Triploceras  verticiUatiun  (Badey).  38.  Docidiiun 
Bacidum  (Breb.),  X 200.  39.  Closterium  didymotocum  (Corda),  X 100.  40,  C.  turgiclum 
(Ehr.),  xlOO.  41.  C.  lineatum  (Ehr.),  XlOO;  42.  Same,  conjugated,  showing  the  double 
sporangium,  xlOO.  43.  C.  attenuatum  (Ehr.),  xlOO.  44.  C.  rostratiun  (Ehr.),  xlOO. 
45.  Penium  interruptum  (Breb.),  x200.  46.  Docidium  Elu-enbergii  (Ralfs),  X 200,  after 
W.  Archer  (Nat.  Hist.  Review,  vii.  p.  375) :  commencement  of  groveth  of  lateral  tube 
preparatory  to  the  formation  of  zoospores.  47.  Same,  the  zoospores  emitted  and  forming 
an  external  cluster  (p.  716).  48-54.  After  De  Bary  (op.  cit.) ;  all  X 190,  showing  develop- 
ment of  sporangimn  of  Cosmarium  Botrytis  (Menegh.) :  48.  The  inner  membrane  with 
contents  escaping  by  bursting  the  outer  wall  of  the  sporangium ;  49.  The  same  escaped, 
somewhat  further  developed,  preparatory  to  segmentation  of  the  contents,  the  external 
membrane  doubled ;  50.  The  same,  division  finished ;  51.  The  same,  H  hour  after ; 
52.  The  same,  at  a  later  stage ;  53.  Germ-cells,  ordinary  vegetative  division  begun ; 
54.  Product  of  the  first  division  of  a  germ-cell,  each  new  half  (but  not  imtil  now)  having 
assumed  the  characteristic  form  of  the  species.  55-60.  After  De  Bary  (op.  cit.),  all  x390, 
showing  development  of  sporangimn  of  Cosmarium  Meneghinii  (Breb.) :  55.  Empty  out- 
side coat  of  a  sporangium  with  an  open  slit  or  fissure  by  which  the  inner  membrane  (with 
contents)  has  come  out;  56.  The  emerged  inner  membrane  and  contents;  57.  A  pair  of 
germ-cells  formed  therein  ;  58.  The  same,  one  escaping ;  59,  60.  Products  of  the  germ- 


DESCEIPTION  OF  THE  EXGEAYIXGS.  951 

cells,  showing  one  segment  the  form  of  the  germ-cell,  the  other,  ordinary  vegetative  division 
supervening,  having  assumed  that  characteristic  of  the  species.  61.  Euastrum  didelta 
(Ralfs),  X 150,  abnormal  condition  of,  after  W.  Archer  (Nat.  Hist.  Review,  vi.  p.  469), 
showing  a  central  irregular  structure  produced  between  the  original  segments,  apparently 
owing  to  the  non-formation  of  a  septum  on  the  resumption  of  vegetative  growth,  and 
forming  with  them  but  one  uninterrupted  cavity;  and  in  tliis  instance  the  new  central 
growth  having  assumed  the  size  and  nearly  the  form  of  an  entu*e  frond,  its  axis  of  growth 
and  plane  of  expansion  are  at  right  angles  to  the  old  segments.  62.  Artlu^odesmus  Incus 
(Hass.),  x300,  abnormal  condition  of,  after  W.  Archer,  I.e.,  showing  an  abnormal  growth 
analogous  to  preceding,  but  carried  on  to  another  vegetative  generation,  the  middle  portion 
being  older  than  those  produced  between  it  and  the  original  segments,  the  whole  still 
forming  witliin  but  one  uninterrupted  cavity.  63.  Cosmocladiimi  pulchellum  (Breb.), 
X250. 

PLATE  lY.  (Diatoms). 

[Plates  rV.  to  YIII.  are  engraved  by  Mr.  TufFen  West.     Many  of  the  figures  are  from  original 
drawings,  others  from  specimens,  and  all  of  them  are  magnified  300  diameters.] 

Figure  1.  Epithemia  turgida,  f.  and  s.  v.  2.  E.  Westermanni.  3.  Eunotia  pentaglypliis. 
4.  E.  triodon.  5.  Amphicampa  mirabilis.  6.  Himantidium  pectinale,  f.  and  s.  v.  7. 
Podosphenia  Eln-enbergii,  f.  and  s.  v.  8.  Rhipidophora  paradoxa.  9.  Licmophora  flabel- 
•lata.  10.  Podocystis  Adriatica.  11.  Sceptroneis  Caduceus.  12.  Dimeregramma  sinu- 
atum,  f.  and  s.  v.  13.  Diatoma  vulgare,  f.  and  s.  v.  14.  D.  elongatum.  15.  D.  Ehren- 
bergii.  16.  D.  hyalinum,  f.  and  s.  v.  17.  Asterionella  formosa.  18.  A.  Ralfsii.  19. 
Bacillaria  paradoxa,  f.  and  s.  v.  20.  B.  cursoria.  21.  Nitzschia  Sigma.  22.  N.  scalaris, 
f.  and  s.  V.  23.  Ceratoneis  longissima,  f.  and  s.  v.  24.  Homoeocladia  Martiana,  f.  and  s.  v. 
25.  H.  fiUformis.  26.  H.  sigmoidea.  27.  Synedi'a  Arcus,  f.  and  s.  v.  28.  S.  pulchella, 
f.  and  s.  V.  29.  S.  capitata.  30.  Amphipleura  pellucida.  31.  A.  inflexa.  32.  Plagio- 
gramma  pulchellum,  f.  and  s.  v.  33.  Dimeregi'amma  nanum,  f.  and  s.  v.  34.  D.  distans, 
f.  and  s.  V.  35.  D.  Tabellaria,  f,  and  s.  v.  36.  Trybhonella  gracilis.  37.  T.  acuminata. 
38.  Campylodiscus  Hibernicus.  39.  C.  spiraHs.  40.  Striatella  unipimctata,  f.  and  s.  v. 
41.  Rhabclonema  minutum,  f.  and  s.  v.  42.  Hyalosu*a  delicatula,  f.  and  s.  v.  43.  Rhab- 
donema  Crozieri,  f.  and  s.  v.  44.  Biblarium  Castellum  (EM.  33. 2. 1.).  45.  Stylobibliiun 
Clypeus.  46.  Gomphogramma  rupestre,  f.  and  s.  v.  47.  Grammatophora  marina.  48. 
G.  serpentina,  f.  and  s.  v.  49.  Gephyria  media,  f.  and  s.  v.  upper  and  imder  valves. 
50.  G,  incm*vata,  f.  and  s.  v.  ditto.  51.  Diatomella  Balfouriana,  f.  and  s,  v.  52.  Disi- 
phonia  australis. 

PLATE  Y.  (Diatoms). 

Figure  53.  Cyclotella  operculata,  f.  and  s.  v.  54.  C.  rectangula,  f.  and  s.  v.  55. 
Actinogonium  septenarium.  56.  Liostephania  magnifiea.  57.  L.  Rotula.  58.  Dictyo- 
lampra  Stella.  59.  Mastogonia  Actinoptychus.  60.  Hyalodiscus  subtilis.  61.  Podosira 
Montagnei,  f.  and  s.  v.  62.  Melosu-a  Horologiima,  f.  and  s.  v.  (EM.  33.  2.  17).  63.  M. 
8ubfle:alis,  f.  and  s.  v.  64.  M.  nummuloides,  f.  and  s.  v.  65.  M.  orichalcea.  66.  Aste- 
romphaliis  Arachne.  67.  Melosira  Roseana,  f.  and  s.  v.  68.  Discosira  sulcata,  f.  and  s.  v. 
69.  Stephanodiscus  ^gyptiacus,  f.  and  s.  v.  70.  Endictya  oceanica,  f.  and  s.  v.  71.  Me- 
losira Borreri,  f.  and  s.  v.  72.  Liparogyra  spiralis,  f.  and  s.  v.  73.  Peristephania  Eutycha. 
74.  Stephanopyxis  Tm'ris.  75.  S.  ferox,  f.  and  s.  v.  76.  Xantliiopyxis  oblonga.  77. 
Stephanogonia  polygona,  f.  and  s.  v.  78.  Coscinodiscus  ovaHs.  79.  Asteromphalus 
Brookei.  80.  Craspedodiscus  Coscinodiscus.  81.  Systephania  Corona.  82.  Halionyx 
undenarius.  83.  Coscinodiscus  stellaris.  84.  Actinocyclus  Ralfsii.  85.  Heterostephania 
Rothii.  86.  Asteromphalus  Darwinii.  87.  A.  elegans.  88.  Actinoptychus  undulatus, 
f.  and  s.  V.    89.  Coscinodiscus  concinnus.     90.  Odontodiscus  eccentricus. 


PLATE  VI.  (Diatoms). 

Figure  1.  Auliscus  pruinosus.  2.  Eupodiscus  Argus :  a,  s.  v. ;  h,  f.  v.  (the  latter 
from  Kiitzing).  3.  Auliscus  sculptus :  a,  s.  v. ;  h,  f.  v.  4.  Aulacodiscus  Oreganus.  5. 
A.  Beeveriae.  6.  Porpeia  quadriceps :  a,  s.  v. ;  h,  f.  v.  7.  Cerataulus  Isevis :  a,  s.  v. ; 
h,  filament.  8.  Hych'osera  compressa,  s.  v.  9.  Cerataulus  turgidus :  a,  s.  v. ;  6,  f.  v. 
10.  Biddulpliia  Tuomeyi:  «,  s.  v. ;  6,  f.  v.  11.  Zygoceros  Mobiliensis:  a,  s.  v. ;  5,  f.  v. 
12.  Biddulphia  Indica.  13.  Hydrosera  triquetra :  a,  s.  v. ;  h,  filament.  14.  Hemidiscus 
cimeiformis:  <r,  s.  v. ;  h,  f.  v.    "^15.  Triceratium  Solenoceros.     16.  T.  exiguum.     17.  T. 


952  DESCEIPTION  OF  THE  ENGRAVINGS. 

venosum.  18.  T.  contortum.  19.  T.  Bpinosum,  20.  T.  punptatum.  21.  T.  alternans : 
a,  8.  V. ;  b,  f.  V.  22.  Amphipentas  flexuosus :  a,  with  five  angles ;  h,  var.  with  four  angles. 
23.  Pleurodesmium  Brebissonii :  a,  s.  v. ;  b,  f.  v.  24.  Cha^toceros  Wighamii :  a,  Gronio- 
thecium-like  frustule,  f.  v. ;  b,  same,  s.  v. ;  c,  s.  v.  of  connecting  zone  and  awns  without  the 
frustule ;  d,  filament  entire.  25.  C.  boreale :  «,  s.  v. ;  b,  f.  v.  26.  Bacteriastrum  furcatum. 
27.  B.  Wallichii :  a,  s.  v. ;  b,  filament  (This  figure  is  introduced  for  the  sake  of  the  f.  v., 
which  so  closely  resembles  Bacteriastrum  furcatum  and  B.  curvatum  as  to  be  undistin- 
guishable  in  this  aspect).  28.  Dicladia  Capreolus :  a,  s.  t.  ;  b,  f.  v.  29.  Gouiothecium 
Odontella :  a,  s.  v. ;  b,  f.  v.     30.  Periptera  tetracladia. 


PLATE  VII.  (Diatoms). 

Figure  31.  Rhizosolenia  Calyptra.  32.  R.  styliformis,  from  a  figure  sent  by  Q-.  Norman, 
Esq.,  Hull.  33.  E-.  setigera.  34.  Syringidium  Americanum.  35.  Hercotheca  mam- 
millaris.  36.  Cocconeis  Placentula.  37.  C.  transversalis.  38.  C  distans.  39.  C.  pseudo- 
marginata.  40.  C.  excentrica.  41.  Achnanthidium  coarctatiim.  42.  Achnanthes  longipes. 
43.  A.  subsessilis.  44.  A.  exilis.  45.  Cymbella  cuspidata.  46.  C.  Ehrenbergii.  47. 
Cocconema  parvxim :  a,  s.  v. ;  b,  f.  v.  48.  C.  Boeckii :  a,  s.  v. ;  b,  f.  v.  49.  Encyonema 
prostratum  (frustules) :  a,  s.  v. ;  b,  f.  v.  50.  Amphora  angularis.  51.  A.  membranacea. 
52.  A.  litoralis.  53.  SyncycHa  Salpa.  54.  Amphora  cymbifera:  a,  upper  surface  in 
focus ;  6,  lower  surface  in  ditto.  55.  Navicula  tumida :  a,  s.  v. ;  b,  f.  v.  56.  Amphora 
ovalis.  57.  A.  spectabilis :  a,  upper  surface  in  focus ;  b,  lower  sm*face  in  ditto.  58.  A. 
hyalina.  59.  A.  marina.  60.  Gomphonema  geminatum.  61.  Navicula  didyma.  62. 
N.  Hitchcockii.  63.  Stauroneis  obliqua.  64.  S.  Crucicula.  65.  Navicula  (Pinnularia) 
major.  66.  N.  producta.  67.  Stauroneis  linearis.  68.  Navicula  rhynchocephala.  69. 
N.  Hennedyi.  70.  N.  latissima.  71.  N.  rhombica.  72.  N.  Amphisba-na:  a,  s.  v. ;  i,  f.v. 
73.  N.  Cluthensis.     74.  N.  borealis.     75.  N.  maxima.     76.  Stauroneis  acuta.     77.  S. 

puicheiia.  )n.nxl: 

PLATE  VIII.  (Diatoms). 

Figure  1.  Oncosphenia?  (Diatoma  elongatum  y,  SBD.).  2.  Eupleuria  ocellata.  3. 
Synedra  robusta  4.  Dimeregramma  pinnatum.  5.  Tessella  interrupta.  6.  Dimeregi-amma 
Harrisonii.  7.  Nitzscliia  Brightwellii.  8.  Euplem-ia  pulchella.  9.  Aclinantliidium 
trinode.  10.  Tetracyclus  lacustris,  s.  v.  11.  Cladogramma  Californicum.  12.  Rhab- 
donema  miriucum,  f.  v.  and  s.  v.  13.  Cyclotella  punctata.  14.  Asteromphalus  centraster, 
punctations  of  compartments  omitted.  15.  Omphalopelta  areolata.  16.  Amphitetras 
oi'nata.  17.  Melosira  arenaria,  s.  v.  18.  Coscinodiscus  nitidus.  19.  Perithyra  denaria. 
20.  Syringidium  bicorne.  21.  Asteromphalus  heptactis.  22.  Euodia  gibba.  23.  Bid- 
dulphia  Macdonaldii.  24.  Aolacodiscus  Kittoni.  25.  Periptera  chlamidophora.  26. 
Coscinodiscus  excavatus.  27.  Triceratium  trisulcum.  28.  Aulacodiscus  pulcher.  29. 
Triceratium  castellatum.  30.  Eunotogramma,  s.  v.  31.  Microtheca  octoceras.  32.  Pleu- 
rosigma  formosum.  33.  P.  Balticum.  34.  Podosira?  compressa.  35.  Attheya  decora. 
36.  Staurogramma  Persicum.  37.  Anaulus  scalaris.  38.  Scliizonema  Grevillii.  39. 
Lysicyclia  Yogelii.  40.  Scliizonema  Dillwj^nii.  41.  Rhizonotia  Melo  ?  42.  Rhizosolenia 
robusta.  43.  Colletonema  eximium.  44.  Omphalotheca  hispida.  45.  Pleurosiphonia 
affinis.  46.  Toxonidea  undulata.  47.  Colletonema  negiectum.  48.  Stigmaphora  rostrata. 
49.  Donkinia  carinata,  s.  v.     50.  Calodiscus  superbus. 


PLATE  IX.  (Diatoms). 

Figure  131.  Melosira  sulcata.  ■*131.  M.  varians.  132.  Actinoptychus  senariu8. 
133-136.  Navicula  viridis.  137,  138.  Svirirella  striatula.  139.  Stauroneis  Phoenic- 
enteron.  140.  Ampliipleura  pellucida.  141.  Navicula  Ampliisba^na.  142.  Stauroneis 
platystoma.  143.  Navicula  nodosa.  144.  Pleurosigma  Balticum.  145.  P.  liippocampus. 
146.  P.  acuminatum.  147,  Sjoiedra  subtilis.  148.  Nitzschia  sigmoidea.  149.  Cyma- 
toplem-a  elliptica.  150-152.  Surirella  splendida.  153.  Amphora  ovalis.  154.  Cymbella 
Ehrenbergii.  155.  Cymatopleura  Solea.  156-161.  Epithemia  turgida  (except,  in  group 
157,  those  figures  marked  with  a  cross).  *157.  Epithemia  Westermanni.  162, 163.  Coc- 
coneis scutellum.  164.  Eunotia  triodon.  165.  Epithemia  granvdata.  166, 167.  Bacil- 
laria  paradoxa.  168.  Diatoma  viilgare.  169.  D.  elongatu.m.  170.  D.  mesodon.  171. 
Himantidium  pectinale.  172.  Odontidium  hyemale.  173-175.  Fragilaria  capucina. 
176.  F.  vii-escens.     177-179.  Meridion  cii-culare.     180-182.  Rhabdonema  arcuatiim. 


DESCB1PTI0^^  OF  THE  ENGEAVrN-GS.  953 

PLATE  X.  (Diatoms  and  Protozoa). 

Figure  183.  Isthmia  enervis.  184.  Spiedi-a  Ulna.  *185.  S.  capitata.  185.  S. 
Ivmaris.  186.  Podosphenia  gracilis.  187-190.  Gomphonema  constrictum.  191-193. 
Licmophora  flabellata.  194,  195.  Cocconema  lanceolatum.  196-198.  C.  Cistula, 
199-202.  Achnanthes  brevipes.  203,  204.  Ehabdonema  arcuatum.  205.  Acineta 
niystacina.  206.  Syncyclia  Salpa.  207.  Scliizonema  Hoffmannii.  208.  Micromega 
Agardliii.  Protozoa: — 209-211.  Cyclidium  G-laucoma.  212.  Pantotriclium  Enchelys. 
213.  Chaetomonas  G-lobulus.  214,  215.  Chgetotyplila  araiata.  216-218.  Cliaetoglena 
Tolvocina.  219,  220.  Peridinium  Tripos.  221.  P.  Michaelis.  222,  223.  Peridinium 
Fusus.  224-226.  Grlenodinium  apiculatum.  227.  Trichodina  tentaculata.  228-230. 
T.  Pediciilus.     231,  232.  Urocentrimi  Tui-bo.     233,  234.  Stentor  Koeselii. 


PLATE  XI.  (Diatoms). 

Figures  1  to  8.  Epithemia  turgida  (Thwaites) :  1.  A  view  of  concave  surface ;  2.  A 
side  view ;  3.  Apposition  of  concave  surfaces  in  the  first  stage  of  conjugation ;  4.  A  front 
view  of  a  single  endochrome,  showing  it  to  have  divided  into  two  segments ;  5.  The  young 
sporangia  lying  transversely  between  the  cleft  parent  frustules ;  6.  The  same,  viewed  end- 
ways, shoAving  their  cylindrical  figure ;  7.  Increased  growth  of  the  sporangia ;  8.  The  pro- 
duced sporangia  ultimately  much  larger  than  parent  fronds,  and  now  striated  like  the 
latter.  At  the  commencement  of  conjugation  the  fronds  are  enveloped  in  mucus,  as  shown. 
9,  10,  11,  12.  Gomphonema  curvatum  (Thwaites),  Ulustratiug  the  process  of  conjugation 
in  this  being,  wliicli  generally  resembles  that  in  Epithemia.  14.  Melosira  nummvdoides 
(Ealfs).  17.  Gomphonema  minutissimum  (Thwaites)  conjugating.  18.  Dinophysis  acuta 
(Ein-.),  f.v.  19.  D.  limbata(Elu:'.),  f.  V.  20  &  27.  Melosira  coarctata  (Ehr.),  f.  vs.  21,22. 
Amphitetras  antediluviana  (Ealfs) :  21.  A  partial  s.  v. ;  22.  filament.  24,  25.  Tetracyclus 
lacustris  (Ealfs) :  24.  Filament ;  25.  A  marginal  view.  26.  Melosira  sulcata  (Ehr.),  a 
filament.  28.  Actinoptychus  Jupiter  (Ehr.).  29.  Melosu-a  Itahca  (Ehr.),  filament, 
30.  Sphenosira  Catena  (Ehr.),  filament.  31.  Actinoptychus?  hexaptera  (Ehr.).  32. 
Ampbipentas?  alternans  (Eiir.).  33.  Asterolampra  Marylandica  (Eiu'.).  34.  Asterom- 
phalus  Hookeri  (Ehr.).  35.  Heliopelta  Metii  (Ehr.).  36.  Symbolophora  Trinitatis  (Ehr.). 
37.  Spii'illina  vivipara  (Ehr.)  :  a  member  of  the  family  Ai'cellina,  having  a  close  affinity 
with  the  calcareous-shelled  Polythalamia  or  Foraminifera.  38.  Craspedodiscus  elegans 
(Ehi\).  39,  40.  Coscinodiscus  radiatus  (Ehr.) :  39.  f.  v. ;  40.  s.  v.  41,  42.  Eupodiscus 
Argus  (Elu\):  41.  f.v.;  42.  s.  v.  (In  fig.  41,  the  sites  of  the  three  tubular  processes, 
which  led  Ehrenberg  at  first  to  call  it  Ti'ipodiscus,  are  seen.)  43,  44.  Triceratium  Favus 
(Elu-.) :  43.  f.  V. ;  44.  s.  v.  45, 46.  Climacosphenia  moniligera  (Ehr.) :  45,  f.  v. ;  46.  s.  v. 
47.  Terpsinoe  musica  (Ehr.).  48,  49.  Grammatophora  gibba  (Ehr.):  48.  f.  v.,  showing 
the  two  imperfect  septa  (vittse,  Kiitz.)  at  each  end;  49.  s.  v.  50,  51.  Zygoceros  Surirella 
(Ehi*.):  50,  s.  V. ;  51.  f.v.  52,53.  Grammatophora  marina  (Elu*.):  52.  f.v. ;  53.  s.  v. 
54.  Hemiaulus  antarcticus  (Ehr.),  f.  v. 


PLATE  XII.  (Diatoms,  Protozoa,  &c.). 

Figure  1.  Amphiprora  constricta  (Elu-.),  f.  v.  2,  3,  4.  Surirella  Gemma  (Ehr.) : 
2,  3.  f.  V. ;  4.  s.  V. :  these  figures  were  intended  especially  to  represent  the  foot-like  pro- 
cesses (ciha  ?)  and  the  foramhia  through  which  these  are  protruded.  5.  Navicula  cuspidata 
(Ehr.;,  s.  v.  6.  N.  amphu-hyncus  (Ehr.),  s.  v.  7,  8,  9.  Stauroneis  phyllodes  (Ehr.): 
7,  8.  s.  V. ;  9.  f.  V.  10, 14,  30.  Stam-oneis  scalaris  (Ein-.) :  10.  s.  v. ;  14.  Process  of  self- 
division  seen  on  f.  v. ;  30,  s.  v.  11.  Campylodiscus  flexuosa  (Ehr.),  f.  v.  12, 13,  22,  23. 
C.  Ehrenbergii  (Ehr.):  12  &  22.  f.  vs. ;  23.  s.  v. ;  13.  Viewed  lying  on  one  end.  15  &  31. 
Navicida  major  (Ehr.):  15.  s.  v. ;  31.  f.v.  16,  Stam-oneis  dilatata  (Ehr.),  s.  v.  17,18. 
S.  Phoenicenteron  (Ehr.) :  17.  f.  v. ;  18.  s.  v.  19,  20.  Surirella  Craticula  (Ehi\) :  19.  f.  v. ; 
20.  s.  V.  21.  Navicula  Tabellaria  (Ehr.),  s.  v.  24,  25.  Epithemia  Librile  (Ehr. ) :  24.  f.  v. ; 
25.  s.v.  Z6,  Amphora  gracilis  (Ehr.),  s.  v.  27.  Epithemia  gibba  (Ehr.),  ventral  surface. 
23  &  53.  Gomphonema  apiculatum  (Ehr.):  28.  f.v.;  b3.  s.v.  29.  Himantidium 
monodon  (Ehr.),  s.  v.  32.  Navicula  affinis  (Elir.),  s.  v.  33.  N.  Chilensis  (Ehr.), 
ventral  surface,  s.v.  34  &  36.  Synedra  Gallionii  (Ehr.):  34.  f.v.  of  fom*  conjoined; 
36.  s.v.  35.  Gomphonema  Vibrio  (Elir.),  s.v.  37.  Amphora  navicidaris  (Ehr.),  f.v. 
38.  A.  Libyca  (Ehr.),  f  v.  39.  Eunotia  quinaria  (Elu-.),  s.v.  40.  Diadesmis  Isevis 
(Ehr.),  f.v.  41.  Cocconeis  Fiimica  (Ehr.),  s.v.  42.  C.  oceanica  (Eln*.),  s.v.  43. -Na- 
vicula Esox  (Ehr.),  s.v.  44.  Nitzschia  valens  (Ehr.),  f.v.  45,  49,  50,  51,  52.  Himan- 
tidium Papilio  (Elu-.):    45  k  51.  Filaments;    49.  A  single  frustule  seen  on  ventral 


954  DESCRIPTION  OF  THE  ENGRAVr^TGS. 

surface;  50&52.  s.  v.  46.  Cocconema  cymbiforme  (Ehr.),  s.  v.  47.  Peridinium  con- 
strictum  (Elii*.) :  the  median  sulcus  or  constriction  is  well  seen  dividing  the  lorica  into 
two  segments — patellce  or  valves,  each  of  wliich  is  here  again  composed  of  several  facettes. 
A  distinct  nucleus  (sexual  gland,  Ehr.)  is  shown.  48  r^  h.  Cocconeis  Americana  (Elu*.): 
48  a.  s.  V. ;  48  h.  Several  frustules  adherent  to  a  portion  of  Conferva.  54.  Himantidium 
Guianense  (Ehr.),  f.  v.  of  a  filament.  55,56,57.  Colletonema  Amphioxjs  (Elu-.):  55. 
B.  v.  of  a  single  frustide  ;  56.  f.  v. ;  57.  A  collection  enclosed  in  their  mucous  investment, 
seen  in  difi'erent  positions.  58.  Sphserozosma?  .  .  .  (Brightwell):  tliis  production  was 
found  by  Mr.  Brightwell  (see  '  Famia  Infusoria  of  Norfolk').  We  cannot  perceive  any 
affinity  between  his  drawing  and  the  members  of  the  genus  Sphcerozosma,  to  which  he  has 
surmised  it  might  belong.  59.  Ceratoneis  Closterium  (Ehr.),  s.  v.  60,  61.  Pleurosigma 
Fasciola  (Ehr.).  62,  63.  Dictyocha  Speculum  (Elu\):  62.  Viewed  in  front;  63.  Viewed 
sideways.  64.  Difllugia  acanthophora  (Ehr.) :  its  surface  illustrates  what  is  termed  an 
imbricate  disposition  of  the  scale-like  markings ;  a  navicular  body  is  represented  in  its 
interior,  as  seen  tln-ough  its  transparent  lorica.  65,  66.  Asplanchna  Brightwellii  (Bright- 
well).  These  two  figures  are  from  Mr.  Brightwell's  book :  65  is  there  described  as  "  a 
young  specimen  (female),  just  emerged,  in  which  the  red  eye  and  germs  of  other  organs 
are  seen ; "  in  66  "  may  be  seen  the  oesophagus  leading  to  the  stomach,  and  above  the 
stomach  two  small  bodies  (either  salivary  or  hepatic  glands),  and  mider  it  the  opaque 
ovisac."  67,  68,  69.  Zoothamniiun  Ai'buscula  (Brightwell) :  these  tln*ee  figures  from 
Mr.  Brightwell  illustrate  the  curious  cycle  in  development  referred  to  in  the  text.  70. 
Vaginicola  .  .  .  ?  (Brightwell) :  apparently  a  Vaginicola  imdergoing  spontaneous  fission. 
71.  Mesocena  heptagona  (Ehr.).  72.  Navicula  cardinalis  (Ehr.),  s.  v.  73.  Stauroneis 
Isostauron  (Elu-.),  s.v. 

PLATE  XIII.  (Diatoms). 

Figure  1.  Amphipleura  pellucida.  2.  A.  rigida.  3.  Surirella  constricta.  4.  Den- 
ticula  elegans.  5,  6,  7.  Amphiprora  alata.  8.  Epithemia  alpestris.  9.  Ceratoneis 
spiralis.  10.  Cocconema  gibbum.  11.  Gomphonema  cm'vatum.  12.  Epithemia  Por- 
cellus.  13.  (left)  Podosphenia  hyalina  ;  (right)  P.  cuneata.  14.  P.  Ehrenbergii. 
15.  Ehipidophora  tenella.  16.  Licmophora  divisa.  17.  Ehipidophora  Nubecula. 
18.  Epithemia  Musculus.  19.  Ehipidophora  Meneghiniana.  20.  Synedra  fulgens. 
21.  Meridion  circulare,  var.  22.  Grammatophora  hamulifera.  23.  Gomphonema 
acuminatum.  24,  25.  Odontidium  hyemale.  26.  Tabellaria  ventricosa.  27.  Ehab- 
donema  Adriaticum.  28.'  Pododiscus  Jamaicensis.  29.  Tabellaria  flocculosa.  30,  31, 
32,  32  a.  Biddulphia  obtusa.     33.  Pyxidicula  Adriatica. 


PLATE  XIV.  (Diatoms). 

Figures  1  to  12.  Fragilaria  capucina.  13.  Himantidium  Soleirolii.  14.  Cym- 
bosira  Agardhii.  15.  Achnantliidium  microcephalum.  16.  A.  delicatulum.  17.  Cyclo- 
tella  Scotica.  13,  19,  20.  Cymbella  gastroides.  21,  Ehaphoneis  Amphiceros.  22. 
Encyonema  prostratum.  23.  Hyalosira  rectangula.  24-28.  Cymbella  Helvetica.  29. 
Hyalosira  obtusangula.  30.  Sphenella  angustata.  31.  S.  obtusata.  32,  33.  Diadesmis 
confervacea.  34,  35  a,  h.  Berkeleya  Adriatica.  36.  Gomphonema  coronatum.  37, 
38  «,  h,  c.  Homoeocladia  pumila.  39-42.  Micromega  pallidum.  43,  44.  M.  bomby- 
cinum.     45,  46.  Homoeocladia  moniliformis.     47-49.  H.  Martiana. 


PLATE  XV.  (Diatoms). 

Figures  1,  2.  Cyclotella  atmospherica  (Elir.).  3.  C.  Atlantica  (Ehr.).  4.  C.  Sinensis 
(Ehr.).  5.  Stawosira  construens  (Ehr.).  6,  7,  8,  9.  Epithemia  longicornis  (Ehr.).  10. 
Goniothecium  crenatiun  (Ehr.).  11.  Epithemia  Argus  (Ehr.).  12.  Navicula  didyma  (Ehr.). 
13.  Desmogonimu  Guianense  (Ehr.).  15.  Naviculatajniata  (Eln-.).  16,17.  Himantidimn 
monodon  (Ehr.) :  16.  Two  frustules  conjoined  in  front  view ;  17.  s.  v.  18, 19,  20,  21, 
Arachnoidiscus  ornatus  (Shadbolt) :  18.  External  membi'ane,  as  seen  when  detached  from 
the  inner  framework,  or  when  viewed  from  the  outside  of  the  shell  as  an  opaque  object ; 
19.  The  inner  framework  is  exliibited  on  a  black  disc  as  an  opaque  object ;  20.  The  mem- 
brane and  framework  united,  as  seen  by  transmitted  light,  x200;  21.  The  same,  more 
amphfied,  XoOO.  22,23.  Campylodiscus  parvulus  (Smith) :  22.  s.v.;  23.  Partial  f.  v. 
24,  25.  Grammonema  Jm'gensii  (Ealfs) :  24.  Front  and  s.v.  of  a  single  frustule;  25.  A 
filament.  26,  27.  Melosira  Niigeli :  a  series  of  figures  to  illustrate  the  distribution  of  the 
chlorophyll  (endochrome),  and  the  presence  of  a  nucleus :  26  a.  viewed  from  the  base ; 


DESCEIPTION  OF  THE  ENGKAVINGS.  955 

26  b.  from  the  lateral  surface ;  two  bands  of  clilorophyll  are  seen  on  each  side,  and  their 
section  at  the  angles ;  26  c.  from  the  base ;  27.  Seen  from  below,  nucleus  with  nucleoli 
and  sap-currents;  lai-ge  and  small  clilorophyll-globules ;  Zl b.  Seen  from  the  side;  the 
two  lateral  bands  of  chloropliyil  are  seen,  and  a  parietal  nucleus,  with  sap-currents  from  it, 
in  the  centre  of  one  side  ;  27  c.  An  individual  after  division,  seen  from  the  side.  The 
chlorophyll  bands  appear  only  in  section.  Each  secondary  cell  has  a  parietal  nucleus. 
28  a,  h,  c,  d.  Bacillaria  Nageli :  a,  viewed  from  the  broad  side,  a  granidar  nucleus  in  the 
centre ;  b,  also  the  broad  side,  an  individual  before  division,  the  nucleus  primarily  divided ; 
c,  division  complete ;  d,  viewed  from  the  base  (in  section).  29  a,  b,  c,  d.  Melosira  Dickieii 
(Thwaites) :  a,  filament,  in  ordinary  state ;  b,  filament,  the  terminal  cells  of  wliich  are 
becoming  converted  into  sporangia ;  c,  sporangia ;  d,  sporangial  frustides  becomuig  deve- 
loped from  one  of  the  halves  of  a  previously  divided  sporangium,  X  220.  30  a,  b.  Mas- 
togloia  Danseii  (Thwaites) :  a,  portion  of  frond,  X  35 ;  b,  a  part  of  same,  X  220.  In  it 
two  frustales  are  shown,  one  in  front,  the  other  on  side  aspect.  31  a,  b,  c,  d.  Dickieia 
ulvoides  (Ralfs) :  a,  natural  size,  in  different  stages  of  growth ;  b,  frustules  (navicular 
bodies)  higiily  magnified  when  fresh ;  c,  one  when  dried ;  d,  a  lateral  view  of  the  same ; 
e,   a  portion  of  frond,  less  highly  magnified,  showing  the  simple  and  binate  frustules. 

32.  Melosira  varians  (Thwaites)  ( =  Grallionella,   Ehr.),  filament  with   sporangia,  X220. 

33.  M.  Italica,  filament  with  sporangia.     34.  Dictyocha  Fibula.     35.  D.  trifenestra. 


PLATE  XVI.  (Diatoms  and  Desmids). 

Figures  1  to  6.  Navicula  (Pinnularia,  Eln-.)  major.  Erom  Schleiden's  '  Principles  of 
Botany,'  to  illustrate  the  structiu'e  of  the  silicious  valve.  1.  s.  v.  (venter,  Ehr.).  "  In  the 
middle  line  are  two  clefts,  terminating  at  the  centre,  as  well  as  at  the  other  ends,  with  a 
little  ch'cular  enlargement,  more  clearly  seen  in  figs.  3  and  5.  The  rounded  spot  in  the 
middle,  and  at  the  two  ends,  is  not  a  hole  as  represented  by  Elu-enberg.  That  such  a  hole 
is  decidedly  sometimes  not  present,  is  seen  in  such  fragments  as  figs.  3  and  5.  In  the 
position  of  the  oblique  lateral  clefts  (striae  or  costae,  Elu-.),  the  valve  consists  of  two  leaves, 
penetrated  by  tlae  clefts,  which,  where  both  the  lamellae  touch  each  other,  are  somewhat 
broader,  which  explains  the  varying  breadth  of  the  clefts  according  to  the  alteration  of  the 
foci.  Fragments  in  which  tliis  structm-e  is  clearly  represented  may  be  frequently  obtained 
by  crushing  the  valve  (fig.  6).  2.  A  front  view,  showing  that  the  rounded  enlargements  of 
the  median  line  are  but  depressions  on  the  external  surface.  The  double  contom-,  denoting 
the  thickness  of  the  wall,  is  well  seen.  Tliis  clearly  shows  that  a  passage  exists  from  the 
top  to  the  bottom  of  the  valve,  wliich  may  be  easily  confu-med  if  the  valve,  or  better  still  an 
oblique  section  of  it,  be  looked  at  from  above ;  fig.  5  is  su.ch  a  section."  7,  8.  Cymato- 
pleura  elliptica  (Smith).  9.  C.  Solea.  10-19.  Ciosterium  Ehrenbergii  (Smith),  showing 
the  stages  in  its  conjugation,  and  the  formation  of  the  sporangia:  10.  A  single  frond  in  its 
ordinary  condition ;  11.  Two  fronds  approaching  to  conjugate ;  12.  Conjugating  fronds 
undergoing  self-division,  the  upper  showing  the  protuberances  through  the  torn  apices  of 
which  the  contents  of  the  divided  fronds  pass  into  the  sporangia ;  13.  Shows  the  passage  of 
the  endoclu'ome-sac  and  its  contents ;  14.  Conjugated  fronds  having  perfected  then*  spo- 
rangia; 15  (after  M.  Morren).  Development  of  the  "propagules"  into  yomig  fronds; 
16,  17,  18,  19  (from  Morren).  Development  of  a  sporangium  into  a  Ciosterium  with 
unequal  segments:  the  figures  are  all  mag-nified  100  times.  20-26.  Surirella  biseriata 
(Smith).  To  illustrate  the  structure  of  the  valve  and  self-division  of  the  frustule :  20.  View 
of  frustules  on  the  completion  of  self-division ;  21.  Apertures  of  costal  canals  seen  in  front ; 
22.  Silex  of  connecting  membrane  after  maceration  in  acid ;  23.  f.  v.  (the  broad  median 
longitudinal  band  is  the  connecting  zone  of  the  two  valves) ;  24.  s.  v. ;  25.  e.  v, ;  26. 
Transverse  section  of  empty  frustule. 


PLATE  XVII.  (Diatoms  and  Phytozoa). 

Figures  506-509.  Pyxidicula  globata.  511  &  515.  Xanthidium  ?  ramosum.  512. 
X.  hirsutum.  513,  514.  X.  ?  difforme.  516-518.  Cainpylodiscus  ClyiJcus.  519-531. 
Spirillum  Bryozoon.     532,  533.  Astasia  navalis.     534.  G-yges  sangmneus. 


PLATE  XVIII.  (Phytozoa). 

Figure  1.  MonasCrepuscidum,  x800.     2.  Monas  Punctum.     3,4.  Uvella  Glaucoma, 
X  350 :  4.  Detached  monads,    5.  Polytoma  Uvella.     6.  Microglena  monadina.    7.  Gle- 


956  DESCRIPTION  OF  THE  ENGEAVINGS. 

nomorum  tingens,  x2o0.  8.  Doxococcus  ruber.  9.  Bodo  intestinalis,  x300.  10  &  21. 
Monas  Lens.  11a,  b.  Cercomonas  lobata.  12  a,  b.  C.  truncata.  13  «,  6.  Amphimonas 
dispar.  14.  Cliilomonas  Paramecivim,  X  380.  15.  Monas  elongata.  16.  Trepomonas  agiUs. 
17.  Monas  globulosa.  18.  Chilomonas  granulosa.  19.  Monas  attenuata.  20.  Cercomonas 
acuminata.  21.  Monas  Lens  (two  figs.).  22.  Cercomonas  longicauda.  23.  C.  Globulus. 
24.  Spiromonas  volubilis.  25.  Pleuromonas  jaculans.  26.  Ileteromita  exigua.  27.  Tre- 
pomonas agilis.  28  a,  b,  c,  d.  Trichomonas  Batrachorum.  29.  Cryptomonas  ovata,  x  300. 
30.  Prorocentrum  micans.  31.  Lagenella  euchlora.  32.  Cryptoglena  conica.  33,  34. 
Trachelomonas  Volvocina.  35  a,  b,  c,  d.  Chonemonas  Scln*ankii :  c,  d.  Yar.  C.  unifilis. 
36.  Astasia  hsematodes.  37-39.  Euglena  sanguinea.  40,  51,  54.  E.  viridis,  encysted 
and  in  act  of  fission.  41,42.  E.  Pyrum,  x400.  43,44.  E.  longicauda.  45.  Ambly- 
opliis  vii'idis.  46.  Euglena  viridis.  47.  Chlorogoniimi  euchlorum.  48  a,  b,  c.  Astasia 
limpida.  49,  50.  A.  contorta.  52.  Euglena  spirogyra.  53,  55.  Eutreptia  viridis. 
56.  Zygoselmis  inaiqualis.  57.  Bacterium  triloculare.  58.  Spirochseta  plicatilis.  59. 
Spirillum  Undula.  60.  Vibrio  Bacillus.  61.  Spirillmn  Undula.  62.  Vibrio  Bacillus, 
63.  Spirodiscus  fidvus.  64.  Vibrio  Rugula.  65,  66.  Sporonema  gracile.  67,  68.  Spi- 
rulina  plicatilis.  69.  Zoogloea  Termo :  a  mucoid  mass  of  Vibrios,  the  individuals  of  which 
are  equivalent  to  Bacteriiun  Termo  of  Dujardin. 


PLATE  XIX.  (Phytozoa). 

Figure  1.  Chromatium  Weissii.  2.  Menoidium  pellucidum.  3.  Tetramitus  descissus. 
4-6.  Mallomonas  Ploslii.  7  a,  b,  c.  Phacotus  \iridis,  8.  Anisonema  Acinus.  9, 10. 
Trypemonas  volvocina.  11.  T.  cylindrica.  12,  Chonemonas  acuminata.  13, 14.  Lepo- 
cinclis  Grlobulus.  15.  Hirmidium  inane.  16.  Clilamydomonas  pulvisculus.  17.  Dinema 
griseolum.  18, 19.  Eutreptia  viridis.  20-31.  Clilamydococcus  (Protococcus)  pluviahs, 
its  forms  and  development,  after  Cohn :  20.  A  still  cell  revived  after  desiccation ;  21.  Cell 
with  nucleus ;  22.  Still  cell  with  dense  external  coat ;  23.  Fission  of  primordial  within  the 
parent  cell ;  24.  Fission  of  a  still  cell,  wall  of  parent  cell  become  gelatinous ;  25.  Division 
of  secondary  cells ;  26.  Fission  of  encysted  cell  into  four  secondary,  and  27.  into  thirty- 
two  cells ;  28.  The  several  cells  produced  set  free,  a  membrane  tin-own  out  around  one ; 
29.  An  irregular-shaped,  Euglena-Hke  zoospore;  30.  A  cell  on  the  point  of  assuming 
the  motile  condition;  31.  A  very  small,  globidar,  encysted  zoospore.  32-37.  Gonium 
pectorale  :  32.  A  perfect  tabular  frond ;  33.  Detached  cells,  showing  their  contractile 
vesicles ;  34.  Four  cells  (gonidia)  united  by  the  radiating  tubular  processes  of  their  external 
membrane,  into  which  the  green  contents  do  not  enter ;  35.  Excepting  one  cell  of  the 
tablet,  all  the  others  have  proceeded,  to  a  greater  or  less  extent,  by  the  process  of  fission,  to 
generate  "  daughter  cells,"  or  the  rudimentary  gonidia  to  form  new  tablets ;  each  one  is 
still  sm-rounded  by  the  "  mother-cell "  wall ;  36.  A  tablet,  of  which  the  original  gonidia 
are  widely  separated,  and  loosely  held  in  sitii  by  the  external  cell-wall ;  fission  has  further 
proceeded,  and  rudimentary  tablets  formed  from  each  original  gonidium,  consisting  of 
sixteen  "  daughter  cells"  (macrogonidia) ;  in  37  the  connecting  bonds  are  quite  dissolved, 
and  the  sixteen  secondary  tablets  set  free:  all  x500.  38-58.  Stephanosphiera  pluvialis, 
exliibiting  its  forms  and  modes  of  development:  38,  An  equatorial  view;  39.  Lateral 
view,  gonidia  spindle-shaped,  with  protoplasmic  elongations ;  40.  Division  of  gonidia  into 
four  "daughter  cells";  41.  Fm-ther  divided  into  eight,  vmited  in  an  annular  form;  42. 
A  fiu-ther-advanced  stage,  macrogonidia  now  forming  distinct  families,  like  the  one  repre- 
sented in  fig.  57 ;  43.  Division  of  gonidia  preparatory  to  forming  microgonidia ;  44.  A 
full-growm  resting  cell ;  45.  Beginning  of  division  of  a  resting  cell ;  45.  Division  into 
four,  outer  membrane  disappeared;  47.  Tapering  of  one  end  of  secondary  or  "daughter" 
cell  preparatory  to  formation  of  ciha ;  48,  49.  Naked  zoospores ;  50.  Encysted  zoospore 
(gonidium);  51.  Resolution  of  all  the  gonidia,  except  one,  of  a  matm'e  Stephanosphaera 
into  microgonidia;  52.  Detached  ciliated  microgonidia;  53.  An  encysted  zoospore  with 
protoplasmic  elongations  of  the  primordial  cell ;  54,  55.  Di\ision  of  encysted  zoospore ; 
56.  More  advanced  stage  of  division  ;  57.  A  young  family  of  eight  cells ;  58.  Another,  with 
the  cellular  envelope  still  visible  within  the  membrane  of  the  mother  cell:  XaOO  (Cohn). 
59-69.  Pandorina  Morum:  59.  Perfect  form,  with  sixteen  gonidia,  side  view;  60.  The 
same,  polar  view ;  61.  A  gonidium,  side  view ;  62.  A  frond  with  the  gonidia  divided ; 
63.  A  more  advanced  frond ;  64.  A  young  frond  of  fig.  63,  after  formation  of  cilia,  set 
free  ;  65,  66.  Young  fronds,  gonidia  pushed  close  togetlier ;  66.  A  polar  view ;  67.  End  or 
polar  view  of  a  frond  like  65,  the  gonidia  of  which  are  encysted  and  tmmed  red  and  their 
gelatinous  envelope  nearly  dissolved ;  68.  A  side  -view  of  tlie  same ;  69.  A  single  encysted 
gonidium.     Figs.  59  to  68  (except  61 ),  X 100 ;  figs.  61  &  69,  x400  (Henfrey), 


BESCEIPTION  OF  THE  EXGEAVINGS.  957 

PLATE  XX.  (PiiYTOzoA). 

Figures  1-14.  Polytoma  Uvella,  forms  and  development  of:  1.  Perfect  form;  2. 
Same,  acted  on  by  chromic  acid,  which  has  separated  the  primordial  cell  from  the  external 
envelope;  3-6.  Stages  of  fission-process ;  7.  Resting  stage  ;  8.  External  membrane  broken 
up  into  granules ;  9.  Pission  into  foiu- ;  10-12.  ilrrangement  of  secondary  or  "  daughter  " 
cells  ;  13.  Contraction  of  body  witliin  external  envelope ;  14.  Body  retracted  from  ante- 
rior extremity:  x300  (Schneider),  15-21.  Fission  and  formation  of  microgonidia  in 
Chlorogonium  euchlorum.  22,  23.  Pandorina  Morum  (?) ;  22.  A  presumed  form  of, 
with  encysted  immature  fronds,  Xl50;  23.  Another  presumed  form,  x220.  24. 
Chlamydococcus  (?),  a  presiuned  form  of;  the  two  internal  globular  cells  of  a  clear 
ruby-crimson  ;  the  moving  granules  pi'obably  monads  ;  suggested  to  be  Spermatozoa,  X  220 
(Currey).  25.  Yolvocina,  a  developmental  phase  of  one  of  the,  having  encysted  gonidia. 
26-28.  SyncryptaVolvox,  x2G0.  29,30.  Synura  Uvella :  30.  Section  of  a  group  (Ehi-.). 
31.  Uroglena  Yolvox.  32.  Yolvox  G-lobator.  33-49.  Illustrations  of  structure  and 
development  of  Yolvox  Globator  (Busk  and  V\'illiamson) :  33.  A  section  showing  parietal 
cells  and  contained  gemmffi  ;  34.  Portion  of  edge  of  an  embryo  Yolvox  viewed  in  the 
equatorial  plane  to  show  the  common  envelope  and  the  position  of  the  subjacent  cells  or 
gonidia  ;  the  last  not  passing  beyond  the  external  gelatinous  (?)  coat  (Busk) ;  35.  Highly 
magnified  view  of  tlu*ee  cells  ;  the  faint  lines  between  indicate  the  limits  of  the  gelatinous 
envelope  of  each  cell ;  36.  Section  of  a  specimen  momited  in  glycerine  (Will.) ;  37.  Cells 
seen  from  above,  shoeing  radiating  threads ;  38.  Oblique  section,  mounted  in  glycerine ; 
39-41.  Single  cells  ;  42-44,  46,  47.  Progressive  development  of  Yolvox  by  fission ;  45. 
Diagi-am  of  a  superficial  view  of  a  portion  of  a  globe  (Will.);  48,  49.  Wiiiter  spores  of 
Yolvox  aiu'eus:  48.  An  earlier  ;  49.  A  later  and  mature  condition  (Busk). 


PLATE  XXI.  (Protozoa). 

Figure  1.  Amoeba  Schultzii,  x330.  2.  A.  globularis,  x330.  3.  A.  porrecta,  x330. 
4.  A.  princeps,  xlOO.  5  a.  b,  c.  Amoebiform  germs  or  "Proteans"  of  Spongilla.  6. 
Miliola  vulgaris.  7-9.  Arcella  vulgaris  ;  8.  A  side  view  ;  9.  Empty  shell.  10.  Difilugia 
globulosa,  xl50.  11.  Euglypha  alveolata,  empty  shell,  x340.  12-14.  Gromia  oviformis  : 
12.  A  young  specimen ;  13,14.  Nuclear  bodies  found  in  (Schultze),  x300.  15.  Arcella 
Okeuii.  16.  Gromia  oviformis,  x300.  17.  Difflugia  pyriformis.  18  a,  h.  Supposed 
young  forms  of  Gromia  Dujardinii :  a,  x72;  b,  x  180.  19  a-f.  D.  Enchelys :  a,  b.  Difi'erent 
forms ;  c.  Contents  resolved  into  granules  ;  d,  e.  Fission  into  two  and  four  portions ; 
/.  Two  individuals  coherent.  20  a,  b.  Early  stage  of  an  undescribed  Miliola :  a,  x  72  ; 
b,  x330  (Schultze).  21,  22.  Miliola  obesa :  21.  A  yoimg  specimen,  x72;  22.  Shell, 
after  the  removal  of  the  calcareous  matter  by  dilute  acid.  23.  M.  Anconensis.  24. 
Animal  contents  of  a  Miliola  after  dissolution  of  the  shell  by  acid ;  displaying  a  constric- 
tion at  each  half  turn,  and  the  delicate  membranous  envelope  at  the  lower  and  larger 
extremity.  25.  Cornuspira  perforata.  26.  Eotalia  Yeneta,  seen  in  front.  27.  Eosahna 
omata.  portion  of  shell  of,  X 100.  28.  Polystomella  venusta,  X  72.  29,  30.  P.  Stella- 
borealis,  seen  in  front,  x72;  30.  Portion  of  cell  to  show  structui'e,  Xl80.  31.  Rotalia 
Yeneta,  shell  after  action  of  acetic  acid,  X 180.  32.  Nuclear  body  from  the  last  chamber 
of  Textilaria  picta,  x330.  33.  Rotalia  Yeneta,  XoO.  34  «,  b.  Acervulina  acinosa; 
b.  Natm*al  size.  35.  Acervulina  globosa,  portion  of  shell,  x300.  36.  Textilaria  picta, 
Xl80.  37.  Acervulina  globosa,  section  through  thickness  of  shell,  x300.  38.  Polymor- 
phina  eihcea,  silicious  matter  detached  by  pressure,  x300.  39.  Polystomella  strigilata, 
animal  substance  with  attached  particles  apparently  assmning  an  independent  existence, 
x330.    40.  Portion  of  contents  of  Gromia  Dujardinii.     (Figures  20  to  40,  Schultze.) 


PLATE  XXII.  (Protozoa). 

Figures  1-3.  Amoeba  radiosa ;  2.  An  older  specimen ;  3.  One  nearly  divided  into 
two.  4,  5.  A.  Limax.  6.  A.  guttula.  7-11.  A.  bilimbosa :  in  7  and  9  the  external 
envelope  strongly  marked  by  a  double  outline ;  a  clear  zone  witliin  it ;  9.  First  stage 
of  encysting ;  10.  A  nucleus  with  a  central  clear  space,  and  one  with  two  nucleoli ; 
11.  A  specimen  acted  on  by  solution  of  iodine  ;  contained  starch-granules  coloured  blue. 
12-18.  A.  actinophora :  in  13  two  pulsating  vesicles  occur ;  15.  Specimen  acted  upon  by 
acetic  acid,  showing  double  outline  of  integument ;  16  contains  refracting  particles  of  a 
crystalline  form  ;  17.  Some  such  particles  isolated,  and  more  highly  magnified ;  18.  Two 
coherent  individuals,  indicative  either  of  fission  or  of  conjugation.  19.  Cadium  marinum. 
20-23.  Amceba  bilimbosa:  20.  Treated  with  iodine,  the  starch-granules  coloured  blue; 


958  DESCEIPTION  OF  THE  ENGEAVIXGS. 

21.  An  encysted  specimen ;  22.  A  ruptured  and  empty  cyst ;  23.  Probably  the  act  of 
fission.  The  large  circular  body  lying  between  the  two  halves  is  an  encysted  Oxytricha 
which  has  been  taken  up  by  the  Amoeba.  24-27.  Cypliidium  aureolum.  28,  29.  Grega- 
rina  Sipuncidi ;  29.  A  double  being,  the  resvdt  of  fission.  30-32.  Progi'essive  develop- 
ment of  the  contents  of  a  Gregarina  from  an  Annelid  (Coeniu-us  variegata)  into  pseudo- 
navicellse,— in  other  terms,  three  pseudo-navicella  capsules.  33.  G.  clavata,  34.  G. 
Sieboldii,  full-grown,  35,  36.  G.  Terebellie ;  36  exliibits  longitudinal  costse.  37.  A 
group  of  Psorospermia,  from  a  cyst  in  the  eye  of  a  Cyprinus  Tinea.  38  a,  h,  c.  Full- 
grown  Psorospermia :  a,  viewed  in  front,  X  900  ;  b,  seen  from  above ;  c,  on  one  side.  From 
the  vesicula  of  Gadus  lota.  39.  PsorosjDermia  from  a  cutaneous  cyst  on  a  Gasterosteus 
(Stickleback),  x580.  40.  Psorospermia  from  a  cyst  of  Gosterosteus  aculeatus;  a  group 
showing  the  different  stages  of  development.  41.  Psorospermia  burst  by  pressm-e  from 
Cyprinus  Brama ;  b,  the  contained  amoebiform  body  isolated,  X  900.  42.  Epipyxis 
Utricvdus.  44,  45.  Microtheca  octoceros.  46.  Opalina  Lumbrici.  47.  O.  armata, 
transverse  fission.     48,  49.  Dinobryon  Sertularia. 

PLATE  XXIII.  (Protozoa). 

Figures  1,  2.  Actinophrys,  figured  as  one  phase  in  the  development  of  Yorticella 
microstoma  by  Stein :  a,  external  coat;  b,  nucleus;  c,  vesicle.  In  2  a  ciliated  embryo 
appears  within  a  distinct  sac.  3-5.  Podophrya  fixa  (?),  represented  by  Stein  as  another 
phase,  besides  figs.  1  and  2,  in  the  development  of  Vorticella  microstoma.  A  ciliated  germ 
is  seen  in  4,  which  in  5  is  about  to  escape.  6-8.  Other  forms  of  Podoph^-ean  AcinctjB  as 
figured  by  Stein :  6,  7.  As  treated  with  acetic  acid  ;  the  development  of  an  embryo  from 
the  nucleus  is  shown  in  figs.  7  and  8.  9-14.  Vorticella-cysts,  after  Stein's  figures.  In  9 
the  nucleus  is  resolved  into  monadiform  germs  ;  10, 11.  Development  of  cyst-contents  into 
secondary  cysts,  which  are  further  seen  in  figs.  12  and  13  as  become  fusiform  and  protruded 
through  the  wall  of  parent  cyst,  so  as  to  discharge  their  monadiform  germs  without,  as  seen 
in  fig.  14.  15,  16.  Acineta  diademiformis,  with  its  embryo.  17-20.  A.  linguifera,  or 
Acineta  with  the  tongue-like  process  attributed  to  Opercularia  berberina ;  20  shows  an 
empty  capsule.  21.  A.  digitata,  or  Acineta  with  the  finger -like  processes.  22,23.  Acineta 
attributed  by  Stein  to  Opercularia  Lichtensteinii ;  23.  A  specimen  acted  on  by  acetic  acid. 
24,  25.  Actinoplnys  oculata  ;  25  represents  three  individuals  in  the  act  of  conjugation, 
treated  with  acetic  acid.  The  contents  of  two  have  intermingled  ;  a  large  vacuole  with  food- 
particles  lies  between  them.  Tlie  individual  on  the  other  side  is  simply  coherent.  (1-26, 
Stein.)  26,  27.  Acineta  ferrum-equinum ;  27  shows  the  escape  of  the  ciliated  embryo. 
The  horseshoe-shaped  nucleus  appears  as  a  clear  space.  28.  Actinopln-ys  Sol.  29,  30.  A. 
Eiclihornii ;  30.  A  highly  magnified  section  to  show  the  reticiilated  structure.  31, 32.  A. 
Sol:  31.  In  the  act  of  self-division  (conjugation  ?)  ;  32  shows  three  vesicular  expansions 
concerned  in  the  introduction  of  food,  and  an  encysted  animalcide  just  brought  to  the 
surface.  33-35.  Podophrya  fixa ;  34.  In  act  of  fission ;  35.  Segment  becoming  one  inde- 
pendent and  about  to  separate.  36,  37.  Encysted  Podoplu-yae.  38,  39.  Stages  of  Podo- 
plnya  towards  encysting.  40,  41.  Aciuetee  with  embryos.  42,  43.  Transformation  of 
the  embryo  into  an  Acineta,  figured  as  commencing  in  43,  and  as  completed  in  42. 


PLATE  XXIV.  (Protozoa). 

Figures  274,  275.  Lacrymaria  Proteus.  276,  277.  Leucopln-ys  patula.  278.  L. 
Spathula.  279,  280.  L.  sanguinea.  281.  Holophrya  Ovum.  282, 283.  Prorodon  teres. 
284-286.  Coleps  liirtus.  287,  287*  288,  289.  Trachelius  Anas.  290.  T.  Ovum. 
291-293.  Loxodes  Rostrum.  294.  Bursaria  Yorticella.  295.  B.  leucas.  296.  B.  Pupa. 
296*.  Spirostomima  vu-ens.  297,  298.  S.  ambiguum.  299.  Phiahna  viridis.  300- 
302.  Glaucoma  scintillans.  303-309.  Chilodon  Cucullulus.  310, 311.  Nassula  elegans. 
312,  313.  Ampliileptus  Anser.  314-316.  A.  Fasciola.  317-319.  Trachelocerca  Olor. 
320.  T.  biceps. 

PLATE  XXV.  (Protozoa). 

Figures  321-323.  Aspidisca  denticulata.  324-328.  Kolpoda  Cucullus.  329-332. 
Paramecium  AureKa.  333.  Uroleptus  Musculus.  334,  335.  Ophryoglena  acuminata. 
336,  337.  Oxytricha  gibba.  338,  339.  Ceratidium  cimeatum.  340,  341.  Kerona 
polyjjorum.  342.  Urostyla  grandis.  343,  344.  Stylonychia  lanceolata.  345,  346. 
Discocephalus  rotatoriiis.  347,  348.  Himantophorus  Charon.  349.  Clilamidodon 
Mnemosyne.     350-353.   Euplotes  Charon.    354,  355.   Ptygura  Melicerta.    356.  Ich- 


DESCETPTION  OF  THE  ENGRAVLiSrGS.  959 

thydium   Podura.     357,   358.   Chcetonotus    Larus.    359,   360.    Glenophora    Trochus. 
361-364.  CEcistes  crystallinus.     365-370.  Couochilus  Volvos. 

PLATE  XXVI.  (PiiYTOzoA). 

The  following  figures  are  derived  from  M.  Dujardin's  excellent  treatise,  '  Histoire  des 
Infusoires' :— Figure  1.  Hexamita  nodulosa.  2.  Authophysa  Miilleri.  3,4.  Acineta 
tuberosa  ;  in  4  the  cilia  included.  5.  Heteromita  ovata.  6.  Crumenula  texta.  7.  Poly- 
selmis  viridis.  8.  Anisonema  sulcata.  9  a,  h.  Oxyrrhis  marina.  10  a,  b.  Ploeotia  vitrea. 
11.  Heteronema  marina.  12  a,  b.  Zyzoselmis  nebulosa.  13.  Peranema  globulosa.  14. 
Cyclidium  distortum.     15.  C.  abscissum.     16  a,  b.  Acomia  Cyclidium  ;  b,  self-dividing. 

PLATE  XXVII.  (Protozoa). 

Figures  1-9.  Vorticella  microstoma :  1.  With  a  bud  growing  from  its  base ;  2.  A 
specimen  about  to  detach  itself  from  its  stalk,  ai^.d  having  a  posterior  wTeath  of  cilia ;  3.  Self- 
division  proceeding  ;  in  4  complete ;  ba,b,  c,  d.  Encysting-process  ;  5  f .  A  cyst  ruptured  by 
pressure,  giving  exit  to  the  included  Vorticella,  apparently  unchanged  ;  6.  Supposed  transi- 
tional forms  from  rudimentary  campanulate  organisms  to  undoubted  Vorticella  ;  7-9. 
Process  of  encysting,  and  progressive  disappearance  of  special  organs.  10-15.  Vaginicola 
crystallina :  10.  Self-division  ;  11.  One  of  the  fission-products  contracted  and  ready  to 
escape  by  means  of  its  posterior  wreath  ;  12-15.  Acinette  formed  from  Vaginicolse.  16-23. 
Epistylis  nutans  :  16.  Two  individuals  on  a  stem  ;  the  ciliary  apparatus  protruded  in  one, 
contracted  in  the  other  ;  17,  18.  Supposed  Acinetce  ;  Acineta-body  of  the  Epistylis ;  in  17 
the  wavy  outline  indicates  the  contractions  taking  place  in  the  integument ;  in  18  the  out- 
stretched ciliary  fibres  or  processes,  two  nuclei,  and  a  large  contractile  vesicle  are  visible  ; 
19.  Another  such  body,  with  its  sm'face  much  contracted,  and  its  contained  substance 
wasted  by  the  development  of  embryonic  nuclei ;  20.  Another  figure  assumed  by  the 
Acineta-body ;  21.  The  ultimately  withered  state  arrived  at  by  the  Acineta-body  of  an 
Epistylis,  after  the  exhaustion  of  its  contained  formative  blastema  by  the  repeated  produc- 
tion of  embryos  ;  22,  23.  Very  young  forms  (probably)  of  the  EpistyKs  nutans,  and  appa- 
rently the  Epistylis  Botrytis  of  Ehrenberg. 


PLATE  XXVIIL  (Protozoa). 

Figtires  1-3.  Nassula  ambigua :  1.  Under  surface ;  the  two  long  articulated  filaments 
within  are  portions  of  Oscillatoriee;  c,  vesicle;  d,  nucleus;  2.  Encysted  specimen ;  3.  Ani- 
malcule forced  from  its  cyst  by  pressure.  4-7.  Glaucoma  scintillans :  4.  Under  sm'face ; 
5.  An  encysted  being,  seen  in  6  undergoing  transverse  fission,  which  in  7  appears  oblique, 
owing  to  a  change  of  position  of  the  resulting  segments.  8, 9.  Prorodon  teres :  9.  Its  nucleus 
surmoimted  by  a  rim-like  nucleolus.  10.  Stylonychia  Mytilus.  (1-10,  Stein.)  11-15. 
Nassula  elegans :  in  11  internal  germs  occur  in  a  cavity  (uterine)  communicating  externally 
by  a  canal  (oviduct) ;  12.  Germ  loosing  itself  from  the  parent ;  13.  A  fission-product 
■enclosing  a  germ  ;  14.  Germ  developing  Acinetiform  tentacles ;  15.  Nucleus  terminated 
at  its  narrow  end  by  a  nucleolus.  16.  Stentor  Miilleri,  surrounded  by  an  envelope  with 
monads  in  its  interior;  17.  Same,  animal  contracted  in  its  case.  (11-17,  Cohn).  18, 19. 
Vaginicola  valvata.  The  valve  is  seen  closed  at  b  in  fig.  18  ;  fission  has  occurred  both  in 
this  and  in  19,  but  the  animal  is  contracted  in  the  former,  and  expanded  in  the  latter 
example;  in  19  the  valve  appears  as  a  streak  parallel  with  one  side.  20-23.  Lagotia 
viridis :  20.  Head  of  a  young  individual ;  21.  Lateral  view  of  animal  and  of  its  ciliated 
head ;  22.  Tip  of  one  of  the  lobes  of  ciliated  head ;  23.  Animal  with  front  \-iew  of  head. 
(18-23,  Wright.)  24-26.  Otostoma  :  the  oral  <3avity  is  seen  as  an  ear-shaped  space ;  in  25 
two  vesicles  also  are  seen  opening  externally.  (Carter.)  27-30.  Coenomorpha  Medusula. 
31.  Panophrys  griseola.  32.  Habi'odon  ciuwatus.  33,  34.  Blepharisma  hyalina.  35. 
Cinetochilum  margaritaceum.  36,  37.  Cyclogramma  rubens.  38,  39.  Stichotricha 
secunda.  40-42.  Ptyxidium  ovulum ;  in  42.  Act  of  fission.  43,  44.  Stichotricha 
secunda.  45.  Colobidium  pellucidimi.  46,47.  Mitophora  dubia.  48,49.  Apionidium 
modestimi.  50,  51.  Lembadion  bulliniun.  52-54.  Baonidiimi  remigans.  55-57. 
Opisthiotricha  tenuis.  58-60.  Megatricha  partita.  61.  Acropisthium  mutabile.  62,  63. 
Siagontherium  tenue.  (27-63,  Perty.)  64  a-k.  Enchelys  Farcimen,  illustrating  change  of 
form  consequent  on  the  introduction  of  food.  65-71.  Nassula  viridis  :  65.  Natm'al  form, 
X370;  66,  67.  Cysts;  70,  69,  68,  71.  Development  of  cyst-contents  into  monadiform 
germs,  enclosed  within  saccular  thectc,  and  at  length  discharged  externally  as  in  fig.  71 : 


960  DESCEIPTIOX  OF  THE  ENGRAVINGS. 

X300  (Cienkowsky).     72,73.  Enclielys  Pupa.     74-76.  Stylonycliia  pustulata:  74.  the 
animalcule  encysted,  x300.     75,76.  Kotating  cells  within  the  cysts,  X  220  (Cienkowsky). 


PLATE  XXIX.  (Protozoa.) 

Figure  1.  Yorticella  Campanula,  viewed  from  the  rentral  aspect.  2.  Carchesium 
polypinum,  viewed  in  front  and  directly  upon  the  ciliated  disc :  i,  the  mouth ;  e,  the  anus. 
3.  Scyphidia  limacina.  4.  Opercularia  berberina,  seen  from  the  back.  5,  6.  Chsetospira 
Miilleri :  6  represents  the  animal  in  motion.  7.  Stentor  polymorphus,  showing  vascular 
canal  around  the  head  and  along  one  side.  (1-7,  Lachmann.)  8-13.  S.  cseruleus,  and  its 
supposed  iutexmal  germs  or  embryos  in  different  stages  of  development  (Eckhard).  14,  15. 
Trichodina  Pediculus :  14.  A  lateral  view ;  15.  Anterior  extremity.  16.  T.  mitra.  17. 
T.  Pediculus,  a  dead,  distended  specimen.  (14-17,  Stein.)  18.  Stylonychia  pustidata, 
encysted  (Stein).  19,  20.  Amphileptus  fasciola:  seen  encysted  in  fig.  19,  and  as  escaped 
from  the  cyst  in  fig.  20.  21-24.  Oxytricha  Pellionella :  21.  Encysted ;  22.  Cyst  acted 
upon  by  hydrochloric  acid ;  23.  Animal  revived  in  its  cyst  prior  to  its  escape ;  24.  The 
free  animal.  25-34.  Paramecium  (Loxodes,  Colm)  Bursaria,  its  structui-e  and  develop- 
ment :  25  to  show  circulation  of  contents ;  26.  Portion  of  integument  liighly  magnified  ; 
(19-26,  Cohn;)  27.  Transverse  fission;  28.  Nucleus  seen  at  c,  the  nucleolus  at  d;  29. 
Embryo  attached  to  the  nucleus ;  30.  Embryo  escaped  but  still  adherent  by  acinetiform 
tentacles ;  31.  Nucleus  and  attached  nucleolus  separated  by  acetic  acid  ;  32,  33.  Nucleus 
and  nucleolus  during  fission  of  animal ;  34.  Nucleus,  nucleolus,  and  commencing  embryo. 
35-47.  Kolpoda  CucuUus,  illustrating  its  forms  and  development :  37.  Acted  on  by  alcohol, 
to  bring  its  nucleus  into  view;  38.  An  animal  contracted  into  a  spherical  shape;  39.  A 
similar  one  undergoing  fission;  40.  Encysted  Kolpoda;  41.  Same,  in  act  of  fission;  42. 
Fission  completed ;  43.  Specimen  treated  with  alcohol ;  44.  Cyst-contents  divided  into 
four ;  cyst- wall  soft  and  irregular ;  45.  Embryo  escaping  from  a  cyst ;  46.  A  ruptured 
cyst  giving  exit  to  encysted  germs,  as  seen  in  47.  48-59.  Cliilodon  Cucullulus :  48  b.  The 
so-called  dental  cyhnder ;  c,  nucleus  and  nucleolus ;  49.  A  specimen  with  a  large  upper 
lip,  equivalent  to  "C.  uncinatus  (Ehr.) ;  50.  Transverse,  and  51.  Longitudinal  fission ;  52. 
Contracted  prior  to  encysting ;  53,  54.  Cysts ;  in  54  an  embryo  developed ;  55.  Appa- 
rently laminated  cyst  discharging  its  contents;  56,  57.  An  empty  cyst,  with  the  aperture 
tln'ough  which  its  contents  have  escaped  remaining ;  58.  A  cyst  containing  a  parent  animal 
and  an  embryo ;  59.  A  liberated  embryo,  equivalent  to  Cyclidimn  Glaucoma  (Ehr.). 
(26-69,  Stein.) 

PLATE  XXX.  (Protozoa,  after  Stein). 

Figures  1-4.  Opercularia  articulata:  2.  A  highly  magnified  view  of  the  head;  3,  4. 
Supposed  Acinet^e  of  this  species ;  an  embryo  shown  in  fig.  4.  5-8.  Ophrydium  versatile: 
In  5  the  animal  is  seen  extended,  and  in  6  contracted ;  7.  Encysted  animal ;  8.  Its  sup- 
posed Acineta.  9,  10.  Carchesium  polypinum :  10.  A  liighly  magnified  view  of  its  stem. 
11.  Epistylis  crassicollis.  12.  Cothurnia  curva.  13,  14.  C.  Sieboldii :  14.  A  side  view. 
15, 16.  C.  Astaci :  16.  Animal  contracted.  17-26.  Spirochona  gemmipara,  and  its  develop- 
ment: 17  exhibits  a  gemma;  18-20.  Progressive  development  of  the  spiral  head  in  a 
gemma ;  21.  Encysted  gemma ;  22.  Supposed  Acineta  (the  Dendrocometes)  in  its  early  stage; 
23.  As  fully  developed ;  24.  Embryo  (seen  in  23)  set  free ;  25.  A  Dendrocometes,  without 
arms,  but  with  a  contained  embryo  ;  26.  A  free  embryo  revolving  on  its  long  axis.  27,  28. 
Spirochona  Scheutenii ;  28.  After  the  action  of  spirit  of  wine.  29-36.  Lagenophrys 
Vaginicola,  its  structure  and  development :  In  29  a  gemma  is  seen  in  the  act  of  fission  ;  in 
30  the  animalcule  has  its  rotatory  apparatus  retracted ;  31  shows  the  detachment  of  the 
head  of  the  animal  from  the  mouth  of  its  sheath,  to  allow  escape  of  a  gemma ;  32.  Act  of 
fission  ;  33.  Formation  of  a  gemma  at  posterior  extremity ;  34.  Several  gemmae  enclosed ; 
35,  36.  Act  of  fission ;  complete  in  fig.  35,  where  the  parent  segment  is  detached  from  the 
orifice  of  the  sheath,  leaving  a  portion  of  its  interior  extremity.  37.  Opercularia  micro- 
stoma: A,  extended;  b,  contracted. 


PLATE  XXXI.  (Protozoa). 

Figures  1-4.  Bursaria  leucas,  and  the  position  and  structure  of  the  trichocysts  found 
in  its  integument :  1.  X  90 ;  2.  Diagram  of  the  margin,  to  show  position  of  trichocysts  in 
the  dermal  layer ;  3.  Trichocysts  projected  from  the  surface  after  the  application  of  acetic 
acid ;  4.  Detached  spiral  trichocysts  in  the  second  stage  of  evolution  from  elongated  oval 
corpuscles  (Allman).    5-6.  Coretliria  Sertulariae :  in  5  the  two  sorts  of  processes  are  both 


DESCRIPTION  OF  THE  EXGllAVIXGS.  9G1 

seen ;  that  in  the  right  is  tlie  normal  form  ;  6.  More  magnified  view  of  the  fusiform  process, 
showing  the  terminal  depression  or  aperture.  7-13.  Lagotia  produeta,  its  structure  and 
development :  7.  Animal  extended,  in  8  contracted ;  9,  10,  11.  Larva  or  embrvo ;  10 
represents  it  attached;  12.  Diagram  of  structure  of  the  sheath,  showing  the  ectoderm 
(colletoderm)  at  a,  the  cliitinous  tube  at  h^  and  the  endoderm  at  c ;  d  points  out  the  mode 
of  overlapping  of  the  several  segments  of  tube ;  13.  Highly  magnified  view  of  a  portion  of 
tube.  14,15.  Zooteirea  religata :  14.  Animal  expanded ;  15.  Contracted.  (5-15,  Wright.) 
16-20.  Peridinium  uberrimum :  17.  Seen  on  opposite  side  to  that  sho^ni  in  13;  18. 
Transverse  fission ;  19.  Same  specimen  after  the  application  of  solution  of  iodine ;  20. 
Nucleus  isolated  (Allman).  21,  22.  P.  depressmn :  21.  A  side-,  22.  A  front-view.  23. 
P.  longipes.  (16-23  after  Bailey.)  24-27.  Djsteria  armata:  25.  Parts  of  mouth  ;  26,  27^ 
Process  between  two  styles:  26.  A  fx-ont-,  and  27  A  side-view  (Huxley).  28.  Turbanella 
hyalina,  dorsal  view :  d,  the  muscular  oesophagus ;  g,  testis ;  /,  mature  Qgg ;  e^  ovary 
(X350).  29,30.  Chgetonotus  maximus  :  29.  Dorsal  view  (  x  350) ;  30.  A  lateral  view. 
31.  Ideal  section  of  Turbanella  hyalina  through  the  generative  organs.  (28-31,  Schultze.) 
32-39.  Noctiluca  militaris :  (32.  N.  punctata,  Busch :  a,  oral  cavity  or  hilum ;  h,  sharp- 
bordered  rod ;  c,  nucleus ;  d,  proboscis  [cilium] ;  /,  brown  corpuscles,  after  Busch  ;) 
33.  Front  view,  a,  the  tooth ;  h,  oral  apertm-e ;  c,  position  of  sujDposed  anus  (after 
Webb) ;  34.  Dorsal  view,  showing  the  groove ;  and  35.  A  latero -inferior  view,  displajang 
the  oral  cavity  with  the  tooth,  d ;  the  cilium  a  gastric  pouch,  e ;  and  a  presumed  anal 
aperture  (Huxley) ;  36-39  (after  Busch) :  36.  A  germ  in  process  of  development ;  37. 
Brown  gi-anular  body,  seen  at  /  in  fig.  32 ;  38.  A  germ ;  39.  Further  advanced,  acquiring 
the  cliaracters  of  a  Noctiluca. 

PLATE  XXXII.  (Rotatoria). 

Figures  371,  372.  Microcodon  Clavus.  373.  Cyphonautes  compressus.  374-378. 
Megalotroeha  albo-flavicans.  379-382.  Tubicolaria'Najas.  383,  383*.  Stephanoceros 
Eichhornii.  384,  385.  Floscularia  ornata.  386,  387.  Melicerta  rhigens.  388-392. 
Limnias  Ceratophylli.  393.  Enteroplea  Hjdatina.  394.  Hydatina  senta.  395,  396. 
Plem'otrocha  gibba. 

PLATE  XXXIII.  (Rotatoria). 

Figures  397,  398.  Furcularia  Reinhardtii.  399  &  417.  Monocerca  bicornis. 
400-402,  &  425.  Polyartlu-a  platyptera.  403.  Diglena  lacustris.  404,  405.  D. 
grandis.  406-408.  Triarthra  longiseta.  409.  Rattulus  lunaris.  410,  411.  Disteimna 
Forficula.  412  &  414.  Triophthalmus  dorsalis.  415.  Eosphora  Najas.  416.  Notom- 
mata  Copeus.  418-420.  N.  Myi-meleo.  421.  N.  Tigris.  422.  Synchivta  pectiuata. 
423,  4254.  Scaridium  longicauda. 

PLATE  XXXIV.  (Rotatoria). 

Figures  425*  426.  Cycloglena  Lupus.  427^29.  Theorus  vemalis.  430-433. 
Lepadella  ovalis.  434-437.  Monostyla  quadridentata.  438-440.  Mastigocerca  carinata. 
441-444.  Euchlanis?  triquetra.  445,  446.  E.  Lynceus.  447-^53.  Salpina  mucronata. 
454-456.  Dinocharis  Pocillum.  457-459.  Monura  dulcis.  460-462.  Colurus  deflexus. 
463-465.  Metopidia  Lepadella.  466,  467.  Stephanops  lamellaris.  468,  469.  Squa- 
mella  oblonga.     470-473.  Callidina  elegans. 


PLATE  XXXV.  (Rotatoria). 

Figure  474.  Hydrias  cornigera.  475.  Typhlina  viridis.  476-480.  Rotifer  vul- 
garis. 481-484.  Actinm'us  Neptunius.  485,  486.  Monolabis  conica.  487-489. 
Philodina  aculeata.  490.  P.  roseola.  491-494.  Noteus  quadricornis.  495-497. 
Anurgea  Squamula,  498.  A.  stipitata.  499-501.  Brachionus  polyacanthus..  502-504. 
Pterodina  Patina.    505.  P.  clypeata. 


PLATE  XXXVI.  (Rotatoria). 

Figure  1.  Melicerta  ringens,  protruded  and  fully  expanded,  with  the  upper  part  of  ita 
tube  at  a ;  ^,  one  of  the  tactile  tubes ;  the  circular  disc  at  c  is  the  pellet-cup ;  at  m  are  the 
jaws  and  gizzard  (oesophageal  head) ;  and  below,  the  stomach ;  c,  a  much  less  magnified 

3  Q 


962  DESCRIPTION  OF  THE  EXGPvAYINGS. 

specimen,  partially  protruded  from  its  tube,  whicli  is  liere  shown  entire,  x300.  2.  Lim- 
nias  Ceratopliylli :  the  end  is  protruded  beyond  the  smooth  tube  or  sheath ;  at  e  is  the 
projecting  chin.  3.  Notommata  aurita,  viewed  laterally,  contracted :  it  exhibits  the  oeso- 
phageal head  and  jaws  (b),  the  intestine,  the  large  ovarium,  the  contractile  sac  below,  the 
gTape-like  ganglionic  mass  in  the  head(^),  and  the  tortuous  vessels  on  each  side,  running 
the  length  of  the  body.  4.  The  same  animal  extended  and  rotating ;  the  ear-like  ciliated 
appendage,  whence  the  specific  name,  is  seen  on  each  side  of  the  head.  4  a.  The  ciliated 
lobes  of  the  rotary  organ  ;  b,  the  gizzard,  with  its  jaws  ;  ff,  the  cerebral  (?)  mass  ;  k,  glands 
above  the  stomach;  o,  large  matured  egg  in  the  ovary.  5.  Notommata  aurita,  viewed 
dorsally,  the  viscera  omitted,  to  show  the  muscular  system ;  the  transverse  muscles  are 
seen  at  t,  and  the  longitudinal,  crossing  them,  at  I ;  the  grape-like  ganglionic  mass 
appears  connected  with  special  muscles,  as  also  the  gizzard,  traced  in  dotted  ovitlme,  and 
the  telescopic-w^orking  tail  or  foot  (b) ;  the  looped  band  at  the  head  (o)  indicates  the 
tubular  cavities  in  the  head-mass.  6.  The  same  animal,  showing  chiefly  its  water -vascular 
system  ;  the  large  sac  near  the  bottom  of  its  cavity  (v)  is  the  contractile  bladder,  from 
wliich  proceed,  on  each  side,  convoluted  tubes  (tortuous  vesicles)  furnished  with  tremulous 
respiratory  tags,  as  near  a ;  the  transverse  muscular  bands  seen  at  f.  6  *.  The  dental 
apparatus  of  the  gizzard  as  seen  in  action.  7,  8.  The  male  of  Asplanchna  priodonta: 
7.  s.  V. ;  8.  f.  V,  T^he  cavity  is  seen  occupied  chiefly  by  the  large  testes  in  fig.  7 ;  the 
sperm-duct  is  represented  opening  externally  at  the  pointed  base.  9.  The  female  of 
Asplanchna  prioclonta:  at  a  are  the  gill-like  fissures;  a  large  oral  cavity  opens  into  a 
narrow  oesophagus,  which  ends  below  in  a  stomach.  One  of  the  strong  longitudinal 
muscles  is  displayed,  also  tortuous  vessels  and  ciliated  tags,  with  an  ovary.  10,  11.  The 
jaws  of  the  Asplanchna  detached. 


PLATE  XXXVII.  (Eotatoria). 

Figure  1.  Stephanoceros  Eicliliornii :  a,  sheath ;  b,  pharynx ;  c,  proventriculus,  or 
crop ;  d,  maxillary  head  with  jaws ;  e,  stomach  with  large  glandular  cells ;  f,  intestine  or 
rectum ;  g,  ovary  with  contained  ova  {g  at  pedicle  indicates  the  longitudinal  muscles  in 
that  segment) ;  it,  respiratory  canal  and  tags.  2.  Ovary  and  the  enveloping  membranous 
sac,  or  uterus,  extending  from  it,  containing  ova  in  different  stages  of  development:  a, 
stroma  of  ovary  with  inherent  ova ;  the  darker  segment  probably  indicates  the  position  of  a 
winter  ovuin  developing ;  b,  ovum  dividing ;  c,  ovum  in  wliicli  division  of  yelk  has  been 
several  times  repeated ;  cl,  an  ovum  in  which  the  rude  outlines  of  the  embryo  are  distin- 
guishable, the  two  eyes  at  d,  and  the  sac  with  the  so-called  luinary  concretion  at  k;  f 
points  to  the  uterine  or  ovarian  enveloping  membrane.  3.  A  very  young  Stephanoceros. 
4.  An  embryo  of  Stephanoceros  immediately  after  its  exit  from  the  shell.  5.  An  ovum  of 
Lacinularia.  6.  Another  ovum  of  the  same,  its  yelk  in  process  of  fission.  7.  A  portion 
of  the  ovary  of  the  same,  with  four  contained  ova.  8.  An  oviun  of  the  same,  in  which 
division  has  been  repeated  several  times.  9.  Another  ovum,  wherein  fission  has  been 
repeated  until  the  yelk  is  broken  up  into  a  number  of  cells.  10.  A  yomig  embryo  of 
Lacinularia  immediately  after  its  exit  from  the  egg.     11.  Another  embryo,  fm^ther  developed. 

12.  Termination  of  a  tentacular  process  of  Melicerta  ringens,  showing  the  piston-hke  disc, 
capable  of  retraction  by  a  muscular  band  affixed  to  it,  and  surmounted  by  a  brush  of  cilia. 

13.  A  view  of  the  same  process,  with  the  brush  of  cilia  extended.  14.  The  same,  with  the 
cilia  retracted.  15.  An  embryo  of  Melicerta  ringens,  wliich  has  attached  itself  and  has 
commenced  the  formation  of  its  case  or  sheath.  16.  An  embryo  of  the  same  animal  as  it 
appears  when  swimming  freely.  17.  Melicerta  ringens,  fully  developed,  with  the  lobes  or 
petals  of  its  ciliary  wreath  {a)  fully  expanded ;  b,  uncini ;  c,  ciliated  process,  representing 
a  fifth  lobe;  dd,  tentacula,  as  shown  in  figs.  12,  13.  14;  e,  jaws;  g,  lower  or  second 
stomach ;  h,  intestine ;  Jc,  coloured  globules ;  I,  suctorial  end  of  pseudopodium ;  on,  muscles ; 
o't,  gland  ;  o,  ovum.  18.  Two  muscular  fasciculi,  showing  transverse  markings.  19. 
Lacinularia  socialis :  a,  pharynx ;  b,  maxillag,  or  jaws ;  c,  muscular  crop ;  d,  stomach ; 
e,  lower  segment  of  stomach,  terminating  in  a  narrow  rectum  and  anus  at  if;  g,  a  glan- 
dular (?)  process ;  h,  ovary ;  ?',  respiratory  canal ;  k,  pedicle  (Huxley).  20.  MaxilljB  of 
Lacinularia  socialis.  21.  Winter  ovum  in  act  of  division.  22.  Segmentation  of  a 
portion  of  the  ovary,  of  a  different  character  from  the  rest,  in  process  of  forming  a  winter 
ovum.  23.  Maxillae  of  Melicerta  ringens,  in  bulb.  24.  Winter  ovum  of  Lacinularia. 
25.  A  portion  of  ovary  of  Notommata  centrura :  a,  the  homogeneous  germinal  spot ;  b,  the 
clear  areola  around  it ;  c,  yelk-matter.  26.  Maxillte  of  Melicerta  ringens.  27.  Winter  ovum 
of  Asplanchna  Sieboldii  treated  witli  solution  of  soda.  28.  Winter  ovum  in  its  natural 
state.  29.  Male  of  Asplanchna  Sieboldii,  viewed  from  the  abdominal  surface :  a  a,  the 
anterior  short  arms ;  b  b,  the  posterior  longer  arms ;  c,  testis,  or  spermatic  sac,  filled  xnih. 
spermatozoa  ;  d,  water- vascular  canal.     30  a,  b,  c,  d,  e,  f.  The  corpuscles  of  the  preceding 


DESCRIPTIOX  OF  THE  EXG RAVINGS.  963 

at  c  represent  the  earliest  stage  of  the  spermatic  particles;  those  at  a  the  mature,  including 
the  rod-like  particles.  31.  The  maxilhe  of  Asplanclma  Sieboldii ;  the  striated  muscular 
bands  moving  them  are  very  distinct.  32.  The  female  of  Asplanchna  Sieboldii :  a, 
pharynx ;  h,  cells  of  stomach ;  c,  horseshoe-shaped  ovary ;  d,  saccular  or  uterine  portion 
of  oviduct,  or  ovarian  sac,  with  contained  mature  ovum ;  e,  contractile  vesicle ;  j\  tags  of 
water-vascular  canal ;  k,  ditto ;  g,  muscular  (?)  cushion  witliin  ciliary  wreath  supporting 
spines. 

PLATE  XXXYIII.  (Rotatoria). 

Figure  1.  Rotifer  inflatus,  body  extended ;  rotary  apparatus  withdrawn.  2,  Tlie 
same  Eotifer,  with  the  horn-like  appendages  of  its  rotary  apparatus  expanded.  3.  The 
same  Rotifer,  strongly  contracted  into  a  globular  form.  4.  Pliilodina  erythrophthalma,  in 
a  contracted  condition,  as  found  when  di-ied.  5.  Euchlanis  triquetra,  viewed  on  the  under 
side:  a  points  to  the  lining  membrane  of  the  lorica  in  wliich  the  muscles  are  inserted; 
h,  muscles ;  c,  ganglionic  enlargement ;  d,  respiratory  tube ;  c,  areolar  tissue  of  head  ; 
/,  oesophagus,  or  tube  between  maxillary  head  and  stomach.  6.  Anursea  heptodon.  7. 
Bracliionus  rubens,  the  young  just  emerged  from  the  shell.  8-10.  B.  Bakeri:  8.  Young 
from  the  Qgg\  9.  Summer  Qg^^\  10.  Winter  egg.  11,  Notommata  centrura,  a  portion  of 
the  respiratory  tulDe,  with  the  ciliary  tags  witldn.  12.  Termination  of  a  tag,  with  the 
cilium  witliin.  13.  A  portion  of  a  water-vascular  canal,  with  ciliated  tags  of  Asplanchna 
Sieboldii.  14.  Diagram  of  head  of  Brachionus  polyacanthus,  viewed  from  the  mouth 
side.  15.  Diagram  of  head  of  the  same,  viewed  from  above.  16.  A  portion  of  the  cerebral 
ganglion  and  of  the  nerves  proceeding  from  it,  and  the  eye  consisting  of  two  portions. 
17.  Eye  of  Brachionus  Bakeri,  detached.  18.  Eye  of  Euchlanis  unisetata.  19.  Eye  of 
Caligus.  20.  Diagram  of  head  (trochal  disc)  of  Philodina.  21.  Diagram  of  same,  viewed 
from  the  mouth  side.  22.  Rattulus  carinatus.  23,  24.  Salpina  spinigera.  25.  Noteus 
quadricornis,  dorsal  view :  «,  maxillre ;  c,  anterior  spinous  cornu  of  lorica ;  c  c,  posterior 
cornu ;  d,  ovary ;  /,  vesicle  of  water-vascidar  system ;  e,  canal  of  ditto ;  h,  stomach  ; 
2,  muscles.  26.  Notommata  centrm'a,  dorsal  view,  suiTounded  by  a  mucous  external 
envelope,  and  hned  by  a  subtegumentary  lamina  or  dermis :  /j,  antenna ;  c,  glandular  sac 
around  oesophagus ;  d,  elongated  process  of  rotary  organ,  called  the  under  lip ;  c,  tags  of 
respiratory  canal ;  /,  stomach,  with  large  glandular  cells  of  its  wall ;  g,  intestine ;  h,  ]3an- 
creatic  glands  ;  i,  vesicle  of  water- vascular  or  respiratory  system ;  k,  cerebrum ;  I,  canal  of 
respiratory  tube  surrounded  by  a  granular  coat ;  o,  ovary ;  p,  ovum ;  n,  muscular  bands ; 
q,  chitiuous  lining  of  oesophagus ;  r,  transverse  muscles.  27.  Bracluonus  Bakeri :  a,  lorica 
or  carapace ;  b,  posterior  horns ;  c,  anterior  horas ;  f/,  lobes  of  trochal  disc ;  e,  siphon  or 
antenna ;  /,  gastric  canal  or  oesophagus ;  g,  convoluted  respiratory  tube ;  /,  pancreatic 
glands.  28.  Asplanchna  priodonta:  a,  longitudinal  muscles;  h,  oesophagus;  c,  stomach; 
d,  ovary ;  e,  pharynx.  29.  Pterodina  Patina,  foot  not  showii :  a  c,  convolutions  of  respi- 
ratory canal ;  b,  longitudinal  striated  muscles.  30.  Polyarthra  platyptera :  a,  ciliated 
tubercular  processes  of  head ;  c,  compound  feathery  processes  used  as  locomotive  organs ; 
d,  mature  ovum  adherent  externally ;  m,  striated  longitudinal  muscles.  31,  32.  Poly- 
chretus  subquadratus.  33.  Maxillae  of  Notommata  vermicularis.  with  the  red  eye,  con- 
sisting of  two  portions  (a).  34.  Maxillae  of  Hydatina  senta.  35.  Maxiilas  of  Albertia 
vermicularis.  36.  Albertia  vermicularis,  x2(X).  (Figured  after  Dujardin,  Huxley,  Leydig, 
and  Party.) 

PLATE  XXXDL  (Rotatoria). 

Figures  1-3.  Lindia  torulosa:  1.  Rotary  organ  retracted;  2.  Dental  apparatus  of 
ditto;  3.  Rotary  organ  expanded.  4-7.  Euchlanis  dilatata:  4.  Female,  lying  on  its 
back,  abdomen  upwards ;  5.  Male,  lying  on  its  back ;  6.  The  granular  heap  from  a  yoimg 
male;  7.  Male,  lying  on  its  abdomen.  8,  9.  Notommata  parasita  (Ehr.):  8.  Male; 
9.  Female.  10-20.  Brachionus  urceolaris :  10.  A  summer  ovum  in  the  act  of  fission  ; 
11.  The  embryo  escaping  from  a  summer  egg,  with  ruptm-e  of  shell ;  12.  A  young  male 
after  its  escape  from  the  egg ;  13.  A  male  escaping  from  tlie  egg ;  14.  A  young  male, 
older  than  fig.  12 ;  15.  Female,  rotary  organ  fully  expanded ;  16.  Female,  with  four  male 
eggs  in  dift'erent  stages  of  development  attached ;  17.  Female,  rotary  organ  retracted, 
tentacular  process  (calcar)  protruded;  18.  Female,  lateral  view;  19.  Maxillary  bulb 
(mastax),  with  teeth  in  position ;  20.  A  winter,  ephippial,  or  lasting  ovum.  21-24.  Bra- 
chionus militaris :  21.  Female,  lying  on  its  back ;  22.  Female,  lying  on  its  abdomen ; 
23.  A  winter  ovum;  24.  A  male  ovum.    (Cohn.) 


^Qli 


964  DESCRIPTIOX  OF  THE  EXGRAYIXGS. 

PLATE  XL.  (Rotatoria). 

Figure  1.  Hvdatina  senta,  female,  lateral  view :  a,  dorsum  and  oral  cavity,  extending 
to  an  apex  at  b ;  c,  mastax  with  maxilla^ ;  d,  canal  between  mastax  and  stomach  ;  /,  cloacal 
orifice ;  g,  vesicle ;  h,  ovary ;  /,  coils  of  respiratory  tube ;  k,  cerebral  ganglion ;  /,  cDiated 
tactile  fossa;  m,  longitudinal  muscles.  2.  Enteroplea  Hydatina,  the  male  of  Hydatina 
senta.  3.  Ova  in  an  immatiu-e  state,  as  found  in  the  unimpregnated  ovary  of  Hydatina 
senta :  a.  germinal  spot ;  b,  germinal  vesicle ;  c,  membrane  of  ovum  occupied  vnih  gi-anular 
yelk-matter.  4.  The  lining  membrane  of  stomach  of  Hydatina  senta,  everted,  sliowing 
cilia.  5.  Yibratile  tag,  supported  on  its  pedicle,  attached  to  the  respiratory  canal.  6.  The 
male  sexual  organs  (of  Enteroplea  Hydatina)  detached,  and  highly  magnified  :  a,  penis ; 
b,  gland  surrounding  its  bag ;  c,  vesicles  with  granides ;  d,  fold  of  integument  surrounding 
penis  when  retracted.  7.  Detached  sjiermatozoa.  8.  Stephanops  muticus,  seen  from 
ben ea til.  9.  Same,  side  view.  10.  Another  view  from  beneath,  or  the  ventral  svu-face. 
11.  Brachionus  Dorcas,  female,  newly  born.  12.  Same,  male,  newly  born  (Gosse). 
13.  B.  Miilleri  (male) :  a,  head  mass ;  b,  eye ;  c,  muscles ;  d,  posterior  mass ;  e,  sperm- 
sac  ;  /,  urinary  concretion ;  g,  foot.  14.  B.  Pala,  male,  newly  born.  15.  Same,  male 
egg,  nearly  mature.  16.  B.  Bakeri.  17.  Sacculus  viridis,  male,  newly  born.  18.  Same, 
female,  with  male  ova  attached.  19.  Bracliionus  angularis,  male.  20.  B.  urceolaris, 
mastax  and  dental  apparatus,  ventral  aspect :  a,  mastax ;  b,  malleus ;  c,  manubrium ; 
d,  articulation  ;  e,  uncus  ;  /.  incus ;  //,  ramvis  ;  h,  fulcrvmi ;  /,  muscle  connecting  the  micus 
with  the  ramus ;  j,  muscle  for  extending  tl^p  malleus ;  /,  muscle  for  thro^ning  in  the 
manubrium ;  k,  muscle  for  bending  the  malleus ;  m,  buccal  funnel ;  n,  salivary  glands ; 
0.  alula.  [These  letters  have  the  same  signification  where  met  with  in  the  following  figures 
after  Gosse:]  21-23.  B.  m-ceolaris :  21.  Jaws  viewed  nearly  from  above;  22.  Dental 
apparatus,  lateral  aspect ;  23.  Buccal  funnel,  salivary  glands,  mastax,  and  dental  appa- 
ratus, dorsal  aspect.  24.  Diglena  forcipata,  jaws  closed,  ventral  aspect.  25.  Floscularia 
ornata.  jaws,  dorsal  aspect.  26.  The  same,  frontal  aspect.  27.  Stephanoceros  Eicli- 
hornii.  jaws,  dorsal  aspect.     28.  Same,  uncus,  oblique  aspect. 


9G5 


INDEX 


THE  DESCRIPTION  OF  THE  FAMILIES  AND  GENERA 
OF  INFUSORIA. 


Acarifeum,  503. 
Achnanthece,  872, 
Achnantlies,  873. 
Achnanthidium,  872. 
Aciueria,  629. 
Acineta,  564. 
Acinetinn,  564. 
Acomia,  613. 
Acropistbium,  614. 
Acfhuscece,  935. 
Actiniscus,  935. 
ActinocYclus,  833. 
Actinogoniiim,  813. 
Arfinophryma,  243,  558. 
Actinophrvs,  559. 
Actinoptychus,  839. 
Actiniirus,  704. 
Alastor,  571. 
Albertia,  693. 
Alhertiens,  693. 
Alysciim,  615. 
Amblyophis,  541. 
Amoeba,  548. 
Amabfea,  548. 
Amphicampa,  765. 
Amphimonas,  498. 
Amphileptus,  636. 
Ampbipentas,  858. 
Ampbipleura,  783. 
Ampbiprora,  921. 
Ampbitetras,  857. 
Ampbora.  880. 
Anaulus,  859. 
Ancyrium,  501. 
Angidiferece,  852. 
Anisonema,  512. 
Ankistrodesmus,  752. 
Autbopliysa,  .500. 
Anurnea,  707. 
Apionidivim,  615. 
Aptogonum,  723. 
Aracbnoidiscus,  841. 
Arcella,  554. 
Arcellina,  551. 
Arthi'odesmus,  736. 
Artbrogyra,  822. 
Aspidisca,  631. 


Aspidiscina,  631. 
Asplancbna,  691. 
Astasia,  539. 
Asfasicpa,  188,  538. 
Asterionella,  779. 
Asterodiscus,  838. 
Asterolampra,  836. 
Asteromphalus,  836. 
Attbeya,  863. 
Aulacodiscus,  843,  938. 
Auliscus,  845. 

Bacillaria,  715. 
Bacillaria,  784. 
Bacteriastriim,  863. 
Bacterium,  532. 
Bffionidiiim,  614. 
Berkeleya,  926. 
Biblarium,  805. 
Biddulpbia,  847. 
BidduljihiecB,  846. 
Blepharisma,  628. 
Bodo,  496. 
Brachiono'a,  706. 
Bracbionus,  709. 
Brigbtwellia,  940. 
Bursaria,  620. 

Cadium,  558. 
Calia,  529. 
Callidina,  701. 
Calodiscus,  802. 
Campylodiscus,  798. 
Carcbesium,  588. 
Cepbalosipbon,  670. 
Cerataulus,  846. 
Ceratidiimi.  642. 
Ceratium,  577. 
Ceratoneis,  782. 
Cercomonas,  497. 
ChcstocerccB,  860. 
Cbfetoceros,  861. 
Cbsetoglena,  575. 
Cbaetomonas,  573. 
Cbaetonotus,  661. 
Cboetospira,  597. 
Cbretotypbla,  575. 


Cliilodon,  624. 
Cbilomonas,  495. 
Cblamidodon,  646. 
Cblamydococcus,  522. 
Clilamydomonas,  146,  521. 
Clu'omatium,  502. 
Chloraster,  494. 
Cblorogonium,  543. 
Cbonemonas,  513. 
CiLIATA,  568. 
Cinetocbilum,  630. 
Cladogramma,  814. 
Clenodon,  684. 
Climacospbenia,  772. 
Closterium,  746. 
Cohalina,  571. 
Cocconeidece,  867. 
Cocconeis,  867. 
Cocconema,  877. 
Coccudina,  648. 
Coelastrum,  755. 
Coenomorpba,  597. 
Colacium,  544. 
Colletonema,  926. 
Colepina,  616. 
Coleps,  616. 
Colpoda,  632. 
Colobidium,  615. 
Colpodea,  631. 
Colurus,  698. 
Conochilus,  664. 
Coretbria,  563. 
Comuspii'a,  558. 
Corycia,  550. 
Coscinodiscece,  827. 
Coscinodiscus,  827. 
Cosmarium,  731. 
Cosmocladiimi,  752. 
Cotlumiia,  603. 
Craspedodiscus,  831,  939. 
Crumenula,  511. 
Crypfomonadina,  140,  505. 
Cryptoglena,  509. 
Cryptomonas,  507. 
Cyclidina,  571. 
Cyclidiura,  497,  572. 
Cycloglena,  690. 


9G6 


IXDEX  TO  THE  FAMILIES  AND  GEXEEA  OF  IXFUSORTA. 


Cyclogramma,  630. 
Cyclotella,  811,  937. 
Cylindi'otheca,  940. 
Cymatoplem-a,  793,  940. 
Cymbella,  875. 
CymheJhcB,  875. 
Cymbosira,  875. 
Cyphiclium,  555. 
Cyplioderia,  557. 

Dasydytes,  661. 
Dendrosoma,  562. 
Denticula,  773. 
DesmidiacecB,  715. 
Desmidiecs,  715. 
Desmidium,  723. 
Desmogonium,  789. 
Diadesmis,  923. 
Diatoma,  778. 
DiafomacccB,  756. 
DiatomecB,  756. 
Diatomella,  810. 
Dickieia,  925. 
Picladia,  863. 
Dictyocha,  935, 
Dictyolampra,  813. 
Didymoprium,  723. 
Difflugia,  553. 
Diglena,  687. 
Bileptus,  638. 
Dimeregramma,  790. 
Dinema,  546. 
Dinobryina,  546. 
Dinobryon,  547. 
Dinocharis,  698. 
Diophrys,  648. 
Diplax,  695. 
Diploneis,  892. 
Dipodina,  713. 
Discocephalus,  645. 
Discosira,  822. 
Diselmis,  511. 
Disoma,  608. 
Distemma,  689. 
Distigma,  544, 
Docidium,  744. 
Donkinia,  920. 
Doxococcus,  495. 
Drepanomonas,  513. 

Emydium,  713. 
Enchelia,  605. 
Enchelys,  607. 
Encyonema,  879, 
Endictya,  831. 
Enteroplea,  677. 
Entomoneis,  921, 
Entopyla,  810. 
Eosphora,  689. 
Ephelota,  562. 
Epipyxis,  546. 
Epistylis,  588. 
Epithemia,  759,  938. 
Eretes,  501. 
Euastrum,  728. 
Eucampia,  937. 


Euchlanidofa,  693. 
Euchlanis,  695, 
Eudorina,  520. 
Eugiena,  541. 
EuglencBa,  188,  538. 
Euglypha,  556, 
Eunotia,  762. 
EunotiecB,  759. 
Eunotogramma,  860, 
Euodia,  852. 
Euphyllodium,  772. 
Eupleui-ia,  809. 
Euplotes,  646. 
Euplotina,  645. 
Eiq)odisce(B,  842. 
Eupodiscus,  842,  938, 
Eutreptia,  546. 

Floscularia,  674, 
Floscularicea,  665, 
Fragilaria,  776. 
Fi-agilariece,  11^. 
Frustulia,  924, 
Eurcularia,  679. 

Gastrochjeta,  615, 
Genicularia,  721. 
Gephyria,  809. 
Glaucoma,  624. 
Glenodinium,  578. 
Glenomorum,  494. 
Glenophora,  662. 
Gloeococcus,  524. 
Gomphogramma,  806. 
Gomphonema,  886. 
G om phoneme oe.  886. 
Gonatozygon,  721. 
Goniothecium,  864. 
Gonium,  152,  517. 
Grammatophora,  807. 
Grammonema,  777. 
Gromia,  556. 
Grymaea,  503. 
Gyges,  516. 
GyrosigTua,  915. 

Habrodon,  614. 
Halionyx,  833. 
Halteria,  644. 
Harmodirus,  629, 
Heliopelta,  840. 
Hemiaulus,  851. 
Hemidiscus,  852. 
Hercotheca,  866. 
Heteromita,  499, 
Heteronema,  545, 
Heterostephania,  833. 
Hexamita,  499. 
Himaiitidium,  765. 
Himantophorus,  646. 
Hirmidium,  528, 
Holophrya,  612. 
Homoeocladia,  784. 
Hyalodiscus,  814. 
Hyalosira,  804. 
Hyalotheca,  722. 


Hydatina,  677. 
Hydatincea,  677. 
Hydrias,  702. 
Hydromorina,  503. 
Hydrosera,  852. 

Ichfhydiyia,  660. 
Ichtliydium,  661. 

Insilella,  827. 
Isthmia,  851. 

Kerona,  642. 
Kolpoda,  632. 
Kolpodea,  631. 
Kondylostoma,  627. 

Labidodon,  682. 
Lacernatcs,  924. 
Lacinidaria,  670. 
Lacrymaria,  609. 
Lagenella,  509. 
Lagenophrys,  604. 
Lagotia,  605. 
Lagynis,  558. 
Larella,  712. 
Lecquereusia,  557. 
Lembadion,  629. 
Lepadella,  694. 
Leptocystinema,  722. 
Leucoplirys,  571,  610. 
Licmophora,  771. 
Licmo^ihorecs,  768. 
Limnias,  670. 
Lindia,  693. 
Liosiphon,  626. 
Liostephania,  813, 
Liparogyra,  823. 
Lithodesmium,  937, 
Loxodes,  619, 
Loxopliyllum,  639. 
Lysicyciia,  815. 

Macrobiotus,  714. 
Mallomonas,  501. 
Mastigocerca,  695. 
Mastogloia,  924. 
Mastogonia,  813. 
Megalotrocba,  665, 
Megalotrochaa,  664. 
Megatricha,  614. 
Melicerta,  672. 
Melosira,  815. 
Melosirea,  810. 
Meiioidium,  502. 
MeridiecB,  766. 
Meridion,  767. 
Mesocena,  936. 
Metallacter,  537. 
Metopidia,  699. 
Micrasterias,  725. 
Microcodon,  665. 
Microglena,  493. 
Micromega,  929. 
Microtheca,  937. 
Milnesiuni,  714. 
Mitophora,  644. 


IXDEX  TO  THE  FAMILIES  AXD  GEXEBA  OP  IXFUSOEIA. 


967 


Monadincu  130,  485. 
Monas,  489. 
Monema,  927. 
Monocerca,  680. 
Monogramma,  875. 
Monolabis,  704. 
Monostyla,  695. 
Moniira,  698. 

Kassula,  625. 
IS'aLinema,  927. 
Navicula,  892,  938. 
NaviculecB,  892. 
IS^itzscliia,  779,  940. 
Noteus,  707. 
Notogonia,  700. 
Notomuiata,  681. 

Octoglena,  690. 
Odontidium,  775. 
Odontodiscus,  832. 
GEcistes,  663. 
(Ecisfma,  663. 
Oniphalopelta,  841. 
Omphalotheca,  865. 
Oncospheiiia,  768. 
Opalina,  569,  627. 
Opalmcea,  569. 
Opercidaria,  592. 
Opliidomonas,  509. 
Ophrydina,  598. 
Ophrydiura,  599. 
Ophri/ocercina,  630. 
Opliiyodendron,  568. 
Ophryoglena,  638. 
Opistliiotricha,  614. 
Otostoma,  639. 
Oxjtricha,  640. 
Oxytrichina,  639. 
Oxyrrhis,  512. 

Pamphagus,  551. 
Pandorina,  157,  517. 
Panopbrys,  627. 
Pautotrichum,  573. 
Paramecium,  634. 
Pediasfre(e,  24,  752. 
Pediastrum,  754. 
Pelecida,  629. 
Penium,  750. 
Peranema,  54.5. 
Peridi7ii(Ba,  574. 
Peridinium,  576. 
Periptera,  865. 
Peristephania,  824. 
Perithyra,  842. 
Peronivmi,  501. 
Phacelomonas,  494. 
Phacotus,  513. 
Phacus,  511. 
Phialina,  623. 
Philodina,  705. 
Philodinaa,  700. 
Phlyctaenia,  925. 
Phytozoa,  485. 
Pinnularia,  892. 


Plagiognatha,  692. 
I  Plagiogramma,  773. 
I  Plagiotoma,  571,  627. 

Plem'odesmium,  860. 
i  Pleuromonas,  502. 

Pleiironema,  639. 

Pleiirosiphonia,  915. 

Plem'osigma,  915. 

Pleiirotrocba,  679. 

Plceofia,  512. 

Pioesconia,  647. 

PodocTstis,  772. 

Pododiscus,  815. 

Podopbrya,  561. 

Podosirai'  815,  938. 

Podosphenia,  769. 

Polyartbra,  686. 

Polyselmis,  540, 

Polytoma,  504. 

Pompbolyx,  712. 

Porocyclia,  823. 

Porpeia,  850. 

Prorocentriim,  509. 

Prorodon,  612. 

Prorostauros,  915. 

Protozoa,  199,  547. 

Pseudo-difflugia,  557. 

Pterodina,  711. 

Ptygura,  661. 

Ptyxidium,  615. 

Pyxidiciila,  824. 

Kattulus,  688. 
Ehabdomonas,  503. 
Eliabdouema,  804. 
Rbapbidogloea,  925. 
Kliapboneis,  791. 
Ebipidopbora,  769. 
Ehizopoda,  243. 
Rbizonotia,  885. 
Rbizosolenia,  865. 
RoTATOKiA,  392,  649. 
Eotifer,  702. 

Salpina,  697. 
Sacculus,  662. 
Scaridium,  686. 
Scenodesmus,  753. 
Sceptroneis,  772. 
Scliizonema,  927. 
SchizonemecB,  924. 
Scypbidia,  596. 
Siagontberimn,  614. 
Sorastrum,  755. 
Spatbidium,  611. 
Spbserosira,  524. 
Spbrerozosma.  723. 
SpbeneUa,  886. 
Spbenoderia,  557. 
Spbenosira,  892. 
Spirillina,  554. 
Spirillum,  533. 
Spirocbreta,  533. 
Spirocbona,  598. 


jpir 


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537. 


SpiromonaSj  502. 


Spirostomum,  622. 
Spirotcenia,  751. 
Spondylomorum.  505. 
Spondylosium,  724. 
Sporonema,  537. 
Squamella,  700. 
Squamidina,  558. 
Stam'astinim,  737. 
Stam'ogramma,  915. 
Stauroneis,  911. 
Stauroptera,  911. 
Staurosira,  791. 
Stentor,  581. 
Stephauoceros,  668. 
Stephauodiscus,  823. 
Stepbanogonia,  814. 
Stepbanoma,  529. 
Stepbanops,  699. 
Stepbanopyxis,  826. 
Stepbanosira,  823. 
Stepbauospbrera,  164,  529. 
Sticbotricba,  644. 
Stigmapbora,  923. 
Striatella,  803. 
StriafeUece,  803. 
Stylobiblium,  805. 
Stylonycbia,  643. 
Surireila,  794. 
SiirireUece,  783,  940. 
Symbolopbora,  833. 
Synapbia,  528. 
Syucbffita,  685. 
Syncrypta,  519. 
Syncyclia,  879. 
Syndendrium,  866. 
Syiiedra,  785. 
Synedrex,  940. 
Synura,  519. 
Syringidium,  SQQ. 
Systepbania,  832. 

Tabellaria,  807. 
Tapbrocampa,  692. 
Tardigrada,  713. 
Tardigi-ada,  714. 
Terpsiiioe,  859. 
Terpainom,  858. 
Tessella,  804. 
Tetmemorus,  746, 
Tetracbastrum,  724. 
Tetracyclus,  806. 
Tetramitus,  501. 
Tetrasiphon,  713. 
Tbeorus,  690. 
Tintinnus.  600. 
Toxonidia,  920. 
Trachelina,  616. 
Trachelius,  618. 
Tracbelocerca,  630. 
Tracbelomonas,  510. 
Trepomonas,  499. 
Triartlu-a,  688. 
Triceratium,  853,  939. 
TricJioda,  608. 
Tricbodina,  583. 
Trichodiscus,  561. 


968 


i:ndex  to  the  families  and  geneea  of  ixfusoria. 


Trichomonas,  500. 
Trinema,  556. 
Trioplithalmus,  689. 
Triploceras,  747. 
Tiyblionella,  792. 
Trypemonas,  513. 
Tarbanella,  381. 
Tubicolaria,  668.    * 
Tjphlina,  702. 

Urceolaria,  596. 
Urocentrum,  585. 


Uroglena,  520. 
Uroleptus,  637. 
Uronema,  615. 
Urostjla,  643. 
Uyella,  492. 

Vaginicola,  601. 
Vaginifera,  598. 
Vibrio,  532. 
Vibrionia,  184,  529. 
Volvocina,  144,  514. 
Volvox,  180,  526. 


Yorticella,  585. 
Vorticellina,  579. 

Xanthidium,  735. 
Xanthiopyxis,  826. 

Zooglcea,  537. 
Zooteirea,  563. 
Zoothamniuiii.  594. 
Zjgoceros,  850. 
Zygoselmis,  544. 


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