Skip to main content

Full text of "Text-book of paleontology"

See other formats 


UNIVERSITY  FARM 


>/^JL 


TEXT-BOOK   OF  PALEONTOLOGY 


^ö^m. 


MACMILLAN  AND  CO.,  Limited 

LONDON  •  BOMBAY  •  CALCUTTA 
MELBOURNE 

THE  MACMILLAN  COMPANY 

NEW    YORK  •  BOSTON  •  CHICAGO 
DALLAS  •  SAN    FRANCISCO 

THE  MACMILLAN  CO.   OF  CANADA,   Limited 

TORONTO 


TEXT-BOOK 


OF 


PALEONTOLOGY 


EDITED  BY 

CHAKLES   R.   EASTMAN,  A.M.,  Ph.D. 

PROFESSOR   OF   PALEONTOLOGY    IN   THE   UNIVERSITT   OF   PITTSBURGH 
AND   CÜRATOR   AT   THE   CARNEGIE    MUSEUM,    PITTSBURGH 

ADAPTED  FROM  THE  GERM  AN  OF 

KARL   A.   VON   ZITTEL 

LATE  PROFESSOR  OF  GEOLOGY  AND  PALEONTOLOGY  IN  THE  UNIVERSITY  OF  MUNICH 


SECOND  EDITION  REVISED  AND  ENLARGED  BY  THE  EDITOR  IN  COLLABORATION 
WITH  THE  FOLLOWING-NAMED  SPECIALISTS  : 

R.  S.  BASSLER,  W.  T.  CAL^LW,  A.  H.  CLARK,  H.  L,  CLARK,  J.  M,   CLARKE, 

J.  A.  CUSHMAN,  W.   H.  DALL,  A.   HANDLIRSCH,  K.  T.  JACKSON,  A.  PETRÜNKEVITCH,  P.  E.   RAYMOND, 

R.   RUEDEMANN,  C.  SCHÜCHEBT,  J.  T.  SMITH,  F.  SPRINGER,  T.  W.  VAÜGHAN,  C.  D.  WALCOTT 

\ 
I 


VOL.  I. 
WITH  ABOUT  1600  ILLUSTRATIONS 


MACMILLAN    AND    CO.,   LIMITED 

ST.    MAETIN'S    STREET,    LONDON 

1913 


COPYRIGHT 


There  i.s  nothing  good  in  tliis  world  but  that  wliicli  is  true." — Diderot. 


First  Edition,  1900 
Second  Edition,  1913 


1 

I 


EDITOR'S  PEEFACE  TO  THE  SECOND  EDITION 

A  NEW  Eiiglish  editioii  of  von  Zittel's  Text-hook  of  Paleontology  having  been 
called  for,  advantage  was  taken  of  the  opportunity  to  prepare  a  thorough- 
going  revision  of  the  first  volume,  in  order  that  an  adequate  account  might 
be  incorporated  of  the  new  knowledge  that  has  been  gained  during  recent 
years. 

Towards  this  end,  a  number  of  specialists  were  invited  to  collaborate  with 
the  Editor  in  preparing  a  fresh  treatment  of  the  leading  groiips  of  Inverte- 
brates,  and  the  present  work  bears  witness  to  the  generous  response  that  was 
made  to  this  invitation.  Many  parts  of  the  work  have  been  entirely  re- 
written,  others  have  been  emended,  rearranged  and  enlarged,  and  the 
Classification  in  various  places  has  been  very  considerably  altered.  The  new 
work,  therefore,  cannot  with  either  justice  or  propriety  be  called  von 
Zittel's  Text-book,  being  in  effect  a  composite  production ;  and  yet  in  scope 
nd  style  it  is  modelled  after  the  well-known  German  original. 

The  names  of  the  diflerent  collaborators  appear  on  the  title-page,  and  the 

ections  that  have  been  revised  or  rewritten  are  credited  in  the  body  of  the 

work  to  the  specialists  responsible  for  them.       To   all  of  his  collaborators 

the  Editor  desires   to  offer  grateful   acknowledgments,   and    to   express   the 

sense  of  his  owii  joersonal  indebtedness  to  them  for  the  large  service  they  have 

endered,  and  for  many  individual  courtesies. 

To  his  friend  and  former  associate  at  Harvard,  Doctor  Eobert  Tracy 
ackson,  the  Editor  is  under  an  Obligation  greater  than  can  be  adequately 
icknowledged  ;  for  besides  having  contributed  practically  a  fresh  account  of 
he  Echini,  Dr.  Jackson  has  carefully  read  the  proofs  of  the  entire  work,  and 
as  offered  in  many  places  most  valuable  suggestions  and  emendations.  Like 
everal  of  the  other  collaborators,  also,  he  has  furnished  the  Originals  for  a 
umber  of  new  figures.  The  total  number  of  fresh  illustrations  has  thus  been 
ensibly  increased.  It  is  hoped  that  the  large  amount  of  painstaking  work 
hich  has  been  bestowed  upon  the  present  treatise  will  be  found  to  yield 
eturns  in  increased  value  and  usefulness  among  students  of  Paleontology 
generally. 


CHARLES  R.  EASTMAN. 


I 


Carnegie  Museum,  Pittsburgh, 
Pennsylvania,  June  5,  1913. 


Al'i'S 


LIST   OF   COLLABORATOKS   FOR   THE 
SECOND   EDITION 

Dr.  Joseph  Augustus  Cushman,  Foraminifera. 

Dr.  T.  Wayland  Yaughan,  Adinozoa. 

Dr.  EuDOLF  EuEDEMANN,  GmptoUtoidea. 

Mr.  Frank  Springer,  Cystoidea,  Blastoidea,  Crinoidea. 

Dr.  Arthur  Hobart  Clark,  Post-Paleozoic  Crinoidea. 

Dr.  Hubert  Lyman  Clark,  Asteroidea,  Holothuroidea . 

Dr.  Robert  Tracy  Jackson,  Echinoidea. 

Dr.  Ray  S.  Bassler,  Bryozoa. 

Prof.  Charles  Schuchert,  Brachiopoda. 

Dr.  William  Healy  Dall,  Pelecypoda,  Gastropoda  {jmrs). 

Prof.  James  Perrin  Smith,  Ammonoidea. 

Dr.  Percy  E.  Raymond,  TriloUta. 

Dr.  Charles  D.  Walcott,  TriloUta  {pars),  Arachnida  (pars). 

Dr.  Ray  S.  Bassler,  Branchiopoda,  Ostracoda. 

Dr.  William  T.  Calman,  Cirripedia,  Malacostraca. 

Dr.  John  M.  Clarke,  Phyllocarida,  Arachnida. 

Dr.  Alexander  Petrunkevitch,  Embolobranchiafa,  Myriapoda. 

Dr.  Anton  Handlirsch,  Inseda. 


ORIGINAL  AUTHOß'S  PEEFACE 

Die  englische  Ausgabe  meiner  Grundzüge  der  Palaeontologie  hat  ein  vom 
deutschen  Original  in  verschiedener  Hinsicht  abweichende  Gestalt  erhalten. 
Der  Herausgeber,  mein  Freund  und  ehemaliger  Schüler  Dr.  Eastman,  suchte 
mit  meiner  Zustimmung  eine  Anzahl  der  hervorragendsten  Specialisten  für 
die  Bearbeitung  einzelner  Thierclassen  zu  gewinnen.  Dadurch  erfuhr  das 
Werk  eine  gründliche  und  sachkundige  Ueberarbeitung,  welche  sich  namentlich 
im  Detail  vortheilhaft  geltend  macht  und  mancherlei  Irrthümer  der  deutschen 
Ausgabe  beseitigte.  Für  diese  mühevolle  und  aufopfernde  Arbeit  bin  ich  den 
Mitarbeitern  des  Text-Book  zu  grossem  Dank  verpflichtet. 

Allerdings  wurde  durch  die  Betheiligung  einer  grösseren  Anzahl  von 
Autoren,  deren  Anschauungen  in  systematischen  Fragen  nicht  immer  unter 
einander  und  mit  denen  des  Autors  der  deutschen  Ausgabe  in  Einklang  standen, 
die  Einheitlichkeit  des  Werkes  nicht  unerheblich  gestört  und  auch  der  ursprüng- 
liche Umfang  verschiedener  Abschnitte  bedeutend  überschritten ;  allein  diese 
Nachtheile  dürften  durch  die  sorgfältigere  Durcharbeitung  des  eigentlichen 
Stoff'es  reichlich  ausgeglichen  sein. 

Die  Revision  der  Crinoideen  hatte  der  verstorbene  Herr  Charles  TFachsrmith, 
jene  der  Asteroideen  und  Echinoideen  Herr  fF.  Percy  Sladeii  übernommen. 
Abgesehen  von  einigen  Abänderungen,  welche  mehr  terminologische  als 
chliche  Fragen  betreffen,  wurde  in  diesen  Abtheilungen  eine  weit  voll- 
tändigere  Aufzählung  und  Charakterisierung  der  fossilen  Gattungen  durch- 
eführt,  als  in  der  deutschen  Ausgabe.  Weitergehende  Umgestaltung  erfuhr 
die  Classe  der  Bryozoen  durch  Herrn  E.  0.  Ulrich.  Die  paläozoischen  Formen 
eind  von  diesem  ausgezeichneten  Kenner  mit  einer  Ausführlichkeit  behandelt, 
welche  nicht  ganz  mit  der  Darstellung  anderer  Abtheilungen  in  Einklang 
steht.  Auch  die  Transferierung  der  bereits  bei  den  Korallen  abgehandelten 
Chaetetiden  und  Fistuliporiden  zu  den  Bryozoen  und  die  dadurch  veranlasste 
doppelte  Darstellung  derselben  ist  eine  Incongruenz,  welche  sich  nur  durch  die 
Meinungsverschiedenheit  über  die  zoologische  Stellung  dieser  ausgestorbenen 

I Organismen  entschuldigen  lässt. 
Eine  durchgreifende  Umarbeitung  haben  die  Brachiopoden  durch  Herrn 
Charles  Schuchert  erfahren.     Während  sich  die  deutsche  Ausgabe  mehr  auf  die 


viii  TEXT-BOOK  OF  PALEONTOLOGY 

Werke  und  Anschauungen  von  Thomas  Davidson  stützt,  folgt  die  englische 
Uebersetzung  sowohl  in  der  Auffassung  der  Gattungen  und  Familien,  als  auch 
in  den  systematischen  Principien  den  neusten  Arbeiten  von  James  Hall,  J.  M. 
Clarke,  und  C.  E.  Beecher.  Die  systematischen  Hauptgruppen  sollen  hier 
zugleich  entwicklungsgeschichtlichen  Phasen  entsprechen  und  das  ganze 
SjT'stem  den  Anforderungen  des  biogenetischen  Grundgesetzes  genügen.  Von 
ähnlichen  Gesichtspunkten  wurden  auch  Professor  Beecher  bei  der  Bearbeitung 
der  Trilobiten  und  Professor  Hyaft  bei  jener  der  Gephalopoden  geleitet.  Es 
ist  mir  zweifelhaft,  ob  die  Zeit  zu  einer  durchgreifenden  Reform  der  bio- 
logischen Systematik,  bei  welcher  weniger  morphologische  und  vergleichend- 
anatomische Merkmale,  als  embryologische  und  phylogenetische  Gesichtspunkte 
im  Vordergrund  stehen,  jetzt  schon  gekommen  ist ;  allein  jedenfalls  sucht  die 
in  Nord  Amerika  gegenwärtig  herrschende  Strömung  auf  einem  neuen  Weg 
zur  Wahrheit  zu  gelangen  und  eine  die  genealogischen  Beziehungen  deutlicher 
wiederspiegelnde  Systematik  zu  erzielen. 

Bei  den  Pelecypoden  hat  Herr  Dr.  JF.  H.  Dali  die  durch  Neumayr  eingeführten 
und  in  den  Grundzügen  mit  einigen  Modificationen  angenommenen  Gruppen 
durch  seine  eigene,  auf  langjährige  Spezialuntersuchungen  basirte  Eintheilung 
ersetzt.  Die  Scaphopoden,  Amphineuren,  Gastropoden  und  Pteropoden 
wurden  von  Herrn  Professor  //.  A.  Pilsbry,  die  Crustaceen  mit  Ausnahme  der 
Trilobiten  und  einiger  anderer  Gruppen  von  Professor  /.  S.  Kingsley,  und  die 
übrigen  Arthropoden  von  meinem  langjährigen  Mitarbeiter  und  Freund 
Professor  S.  H.  Scudder  in  sachkundigster  Weise  durchgesehen. 

Für  den  wichtigen  Abschnitt  der  Gephalopoden  trägt  Herr  Professor 
Alpheus  Hyatt  die  Verantwortlichkeit.  Hier  treten  die  Differenzen  mit  der 
deutschen  Ausgabe  am  auffallendsten  zu  Tage,  vertritt  doch  dieser  Autor  am 
entschiedensten  die  moderne  Richtung  in  Amerika.  Obwohl  meine  An- 
schauungen über  verschiedene  Grundprinzipien  der  Systematik,  namentlich 
über  Abgrenzung  von  Familien,  Gattungen  und  Arten  von  denen  meines 
amerikanischen  Collegen  abweichen,  so  glaubte  ich  doch  einem  so  hervorra- 
genden Kenner  der  fossilen  Gephalopoden  bei  der  Bearbeitung  des  von  ihm 
übernommen  Abschnittes  völlig  freie  Hand  lassen  zu  müssen.  Das  Text- 
Book  ist  dadurch  um  eine  Averthvolle  Originalarbeit  bereichert  worden,  welche 
viele  bis  jetzt  noch  nicht  veröffentlichte  Thatsachen  enthält. 

Zu    ganz    besonderem    Dank   bin    ich   dem    Herausgeber    der    englischen' 
Ausgabe  Herrn  Dr.  C.  R.  Eastman  verpflichtet.     Er  hat  keine  Mühe  gescheut, 
das  Werk  mit  den  neusten  Ergebnissen  der  paläontologischen  Forschung  in 
Einklang  zu  bringen  und  den  Fortgang  derselben  zu  fördern. 

Dr.  KARL  A.  von  ZITTEL. 

München,  im  Septe^yiber  1899. 


EDITOK'S  PREFACE  TO  THE  FIRST  EDITION 

The  Gnmd.ziige  der  Paldeontologie,  which.  forms  the  basis  of  the  present  work, 
was  published  in  the  spring  of  1895,  only  a  short  time  after  the  completion 
of  the  fifth  and  last  vohime  of  Professor  von  Zittel's  celebrated  Handbuch  der 
Falaeontologie.  Of  the  latter,  an  excellent  translation  exists  in  French  by 
Barrois ;  but  English-speaking  students  are  without  either  an  independent 
treatise  on  Paleontology  or  translation  from  any  foreign  work,  which  is 
comparable  in  scope  and  character  to  the  writings  of  von  Zittel. 

With  the  hope  of  supplying  this  deficiency  the  Editor  undertook  the  task 
of  rendering  the  Grundzüge  into  English.  It  was  at  first  intended  to  bring 
out  a  strictly  literal  translation,  but  with  the  Author's  consent  this  plan  was 
modified  in  important  respects  which  should  be  clearly  understood  by  all. 
The  chapters  on  Protozoa  and  Coelenterata  stand  here  essentially  as  in  the 
original,  but  nearly  all  the  remaining  chapters  have  been  remodelled,  enlarged, 
and  brought  as  nearly  as  possible  up  to  date  by  a  selected  body  of  experts. 

The  greater  part  of  the  work  is  therefore  a  composite  production,  and 
from  the  nature  of  the  case  some  incongruities  in  style  and  treatment  are  to 
be  expected.  For  all  the  collaborators  to  have  adhered  to  uniform  limits  of 
alteration  and  expansion  would  have  been  impossible.  It  will  be  found, 
therefore,  that  some  portions  of  the  revised  text  are  not  sensibly  difFerent 
from  the  original  while  others  are  changed  very  radically,  and  a  few  chapters, 
notably  the  Molluscoidea,  Mollusca,  and  Trilobites,  are  entirely  rewritten.  An 
eftort  has  been  made  throughout  to  adapt  the  text  more  especially  to  the 
needs  of  Anglo-American  students,  and  the  bibliographies  have  been  enlarged 
with  similar  intent. 

For  all  changes  in  the  Classification  over  the  original  tho  revisers  of  the 
different  sections  are  responsible ;  but  although  radical  departures  have  been 
made  with  the  Author's  sanction,  one  must  by  no  means  presume  he  is  thereby 
committed  to  all  the  innovations  which  are  set  forth.  How  far  and  whether 
in  all  cases  the  system  has  been  improved  must  be  left  for  experience  to 
determine.  The  Author's  graciousness,  however,  in  yielding  his  own  prefer- 
ences  on  systematic  points  will  be  apparent  on  reading  his  annexed  preface. 

Due    acknowledgments    are   rendered   the    collaborators   in   the   Author's 


X  TEXT-BOOK  OF  PALEONTOLOGY 

preface,  and  also  in  footnotes  at  the  end  of  the  several  chapters.  Their 
names  are  enumerated  below  in  the  order  of  their  respective  sections,  and  the 
Editor  begs  to  express  at  this  time  a  sense  of  his  profound  appreciation  of  the 
Services  that  have  been  so  generously  rendered.  For  the  many  personal 
courtesies  extended,  he  would  return  to  each  of  them  his  sincere  and  hearty 
thanks. 

LIST  OF  COLLABORATORS 

Mr.  Charles  "Wachsmuth,  Grinoidea,  Blastoidea. 

Mr.  W.  Percy  Sladen,  Astero^wa,  Echinowa. 

Dr.  George  Jennings  Hinde,  Vermes. 

Mr.  Edward  0.  Ulrich,  Bryozoa,  Ostracoda. 

Mr.  Charles  Schuchert,  Brachiopoda. 

])r.  William  H.  Dall,  Pelecypoda. 

Prof.  Henry  A.  Pilsbry,  Gastropoda. 

Prof.  Alpheüs  Hyatt,  Gephalopoda. 

Prof.  Charles  E.  Beecher,  TrUohita. 

Prof.  John  M.  Clarke,  Eucrustacea  (pars),  Äcerata  (pars). 

Prof.  John  S.  Kingsley,  Eucrustacea  (pars),  Äcerata  (pars). 

Prof.  Samuel  H.  Scudder,  Insecta. 

The  Editor  is  also  greatly  indebted  to  his  friend  Dr.  John  C.  Merriam, 
who  undertook  the  translation  of  the  entire  chapter  on  Mollusca,  a  very 
laborious  work.  Dr.  Merriam's  assistance  has  been  further  enlisted  in  the 
translation  of  the  second  volume,  which  will  be  devoted  exclusively  to  the 
Yertebrates.  Dr.  August  F.  Foerste  Avas  kind  enough  to  furnish  a  transla- 
tion of  the  chapter  on  Insects,  and  various  friends  have  assisted  in  correcting 
proofs.  For  the  compilation  of  the  index  the  Editor  is  indebted  to  Miss 
Elizabeth  B.  Bryant,  a  former  Student  of  his  at  KadclifFe  College,  and  to 
his  brother,  Mr.  David  P.  Eastman. 

CHARLES  E.  EASTMAN. 

Harvard  University, 
SeiJtemher  15,  1899. 


CONTENTS 


INTRODUCTION 


PHYLUM    III. 

Vermes  (Worms)         .... 


PAGE 


Definition  and  Scope  of  Paleon tology     .....         1 

PHYLUM    I. 

Protozoa       .  .  .  .  .  .  .  .  .17 

PHYLUM    IL 

Coelenterata  (Zoopliytes)     .  .  .  .  •  •  .46 


.      135 


PHYLUM    IV. 

ECHINODERMATA  .  .  .  .  •  •  •  .143 

PHYLUM    V. 

MOLLUSCOIDEA  .  .  .  •  •  •  •  .314 

PHYLUM    YL 
Mollusca      .........     421 

PHYLUM    VIL 

Arthropoda  (Articiüates)       .......     690 


INDEX 823 

xi 


INTßODUCTION 


DEFINITION  AND  SCOPE  OF  PALEONTOLOGY 

Paleontology  (Aoyos  row  TraXatCov  ovTOiv)  is  the  Science  which  treats  of 
the  life  which  has  existed  on  the  globe  during  former  geological  periods.  It 
deals  with  all  questions  concerning  the  structure,  Classification,  relationships, 
descent,  conditions  of  existence,  and  distribution  in  time  and  space  of  the 
ancient  inhabitants  of  the  earth,  as  well  as  with  those  theories  of  organic  and 
cosmogonic  evolution  which  result  from  such  inquiries. 

Under  the  term  of  fossils  are  understood  all  remains  or  traces  of  plants 
and  animals  which  have  lived  before  the  beginning  of  the  present  geological 
period,  and  have  become  preserved  in  the  rocks.  The  criterion  which 
determines  the  fossil  character  of  organic  remains  is  the  geological  age  of  the 
formation  in  which  they  occur,  whereas  their  mode  and  State  of  preservation, 
or  the  fact  of  their  belonging  to  extinct  or  to  still  living  species,  are  merely 
incidental  considerations.  Although  fossils  have,  as  a  rule,  undergone  more 
or  less  radical  changes  during  the  process  of  fossilisation,  and  are  usually 
transformed  into  mineral  substances,  nevertheless,  under  exceptionally 
favourable  conditions  (as  in  frozen  ground,  amber,  resin,  peat,  etc.),  plants 
and  animals  may  be  preserved  through  geological  periods  in  a  practically 
unaltered  state.  Carcasses  of  mammoths  and  rhinoceroses  entombed  in  the 
frozen  mud-cliffs  of  Siberia,  and  inclusions  of  insects,  spiders  and  plants  in 
amber  are  none  the  less  genuine  fossils,  in  spite  of  their  having  sustained  no 
trace  whatever  of  mineral  infiltration. 

A  considerable  number  of  plants  and  animals  occurring  as  fossils  in  Tertiary 
and  Pleistocene  formations  belong  to  still  living  species ;  while,  on  the  other 
hand,  the  remains  of  forms  which  have  become  extinct  during  historical  times 
(Ehijtina,  Alca,  Didus,  Pezophaps,  etc.)  can  no  more  be  classed  as  fossils  in  the 
true  sense  of  the  word  than  all  such  recent  organisms  as  may  chance  to 
become  buried  in  deposits  now  forming  under  the  present  prevailing  orographic 
and  climatal  conditions. 

The  changes  which  organic  bodies  undergo  during  the  process  of  fossilisa- 
tion are  partly  chemical  and  partly  mechanical  in  their  nature.^  According 
as  certain  portions  of  the  original  substance  are  removed,  or  are  replaced  atom 

^    White,  Charles  J.,  Conditions  of  preservation  of  invertebrate  fossils.     Bull.  U.S.   Geol.  and 
Geog.  Survey  Territ.,  1880,  vol.  v. ,  p.  133.      Trahucco,  G.,  La  Petrificazione.      Pavia,  1887. 
VOL    I.  B 


2  ELEMENTS  OF  PALEONTOLOGY 

for  atom  by  foreign  matter,  the  result  may  be  either  carbonisation,  decom- 
position,  total  dissipation,  or  petrifaction. 

Carbonisation  is  a  deoxidising  process  taking  place  under  water  or  with 
limited  access  of  air,  and  especially  common  among  plants.  Fossil  wood  and 
other  vegetable  matter  abound  in  peat,  lignite  and  bituminous  coal,  the 
leaves  being  transformed  into  a  thin  flake  of  carbon,  on  which  often  the  finest 
venation  is  still  discernible.  In  some  cases  chitinous  animal  structures  also 
become  carbonised,  as  in  insects,  crustaceans  and  graptolites. 

Becomposition  as  a  rule  effectually  destroys  all  organic  carbon  and  nitrogen 
Compounds.  With  few  exceptions,  therefore,  animals  without  hard  parts, 
such  as  Worms,  infusorians,  naked  mollusca,  most  hydrozoa,  many  anthozoa, 
and  the  embryos  of  vertebrates,  leave  no  traces  behind  in  the  rocks.  Hörn, 
hair,  chitin  and  similar  structures  are  likewise  totally  destroyed  during  the 
fossilisation  process,  while  only  under  especially  favourable  conditions,  as 
in  ice  or  in  frozen  soil,  muscular  and  epidermal  tissues  remain  unchanged ; 
or  eise,  through  the  taking  up  of  lime  phosphate  in  argillaceous  and  calcareous 
deposits,  undergo  a  sort  of  petrifaction,  in  which  the  finer  structure  is  but 
little  altered. ^  Even  the  conservable  hard  parts  of  animal  bodies  are  deprived 
of  their  organic  Compounds ;  bones  give  up  their  fats  and  oils,  and  the  shells 
of  moUusks,  echinoderms  and  crustaceans  lose  their  pigments  and  soft  sub- 
stratum.  The  hard  portions,  which  first  become  more  or  less  porous  through 
loss  of  their  organic  constituents,  next  suffer  the  gradual  disintegration  of 
their  inorganic  Compounds,  and  finally  undergo  dissolution,  reabsorption, 
or  petrifaction. 

Petrifaction. — In  this  process  foreign  substances  soluble  in  water  (chiefly 
calcium  carbonate  and  silica,  more  rarely  pyrites,  iron  oxyhydrate  and  other 
salts)  impregnate  and  completely  fill  all  original  cavities  as  well  as  those 
formed  subsequently  by  decay.  Chemical  metamorphism  takes  place 
occasionally,  when,  owing  to  the  decomposition  of  certain  inorganic  con- 
stituents, the  original  molecules  become  replaced  by  those  of  other  substances. 
For  instance,  we  find  quartz  pseudomorphs  after  calcareous  tests  and  skeletal 
parts,  and  conversely,  calcite  pseudomorphs  after  silica,  as  in  certain  sponges. 

Wherever  the  space  originally  occupied  by  soft  parts,  as,  for  example,  the 
interior  of  a  shell  or  other  hoUow  body,  becomes  filled  up  with  infiltrating 
ooze,  while  the  shell  itself  or  the  enclosing  wall  decays,  there  is  produced  a 
cast  of  the  interior,  which  in  most  cases  (especially  where  the  shell  is  thin,  as  in 
ammonites,  brachiopods,  certain  moUusks  and  crustaceans)  preserves  an  exact 
copy  of  the  original  form,  and  is  susceptible  of  as  accurate  determination  as 
the  real  object.  Not  infrequently  fossil  organisms  leave  molds  or  imprints  of 
their  shells  or  skeletons — very  rarely  of  their  whole  bodies — in  the  rocks. 
Sometimes,  indeed,  their  presence  is  indicated  merely  by  tracks  or  footprinfs. 

Fossils  are  often  distorted  by  mechanical  agencies,  such  as  faulting,  folding, 
crushing,  and  other  deformations  of  the  country  rock.  Such  cases  require 
especial  attention,  and  due  caution  must  be  observed  in  their  determination. 

Paleontology  and  Biology. — Although  the  fossil  remains  of  ancient 
life-forms  yield  but  a  fragmentary  record  of  themselves,  are  almost  never 
perfectly  preserved,  and  are  usually  more  or  less  altered  in  appearance,  yet 
on  the  whole,  they  readily  fit  into  place  in  the  great  framework  of  zoological 

^  Reis,  Otto,  Über  petrificirte  Muskulatur.      Arch.  Mikros.   Anat.,  vols.  xli.  xliv.  lii. , — Dean, 
B.,  Preservation  of  muscle-fibres  in  sharks,     Amer.  Geol.,  1902,  vol.  xxx. 


INTRODUCTION  3 

and  botanical  classifications.  Notwithstanding  all  their  difFerences,  their 
general  structure  is  similar  to  that  of  recent  organisms,  and  their  Identification 
requires  the  most  careful  comparison  with  nearly  related  plants  and  animals. 
The  methods  of  paleontological  research  do  not  differ  from  those  employed 
by  the  zoologist  and  botanist,  excepting,  of  course,  that  the  paleontologist  is 
restricted  to  those  pärts  which  are  alone  capable  of  preservation,  and  must 
reconstruct  the  missing  soft  parts  ideally  from  analogy  with  recent  forms.  It 
is,  nevertheless,  incumbent  on  the  paleontologist  to  obtain  all  possible  Informa- 
tion from  the  material  such  as  it  is,  aided  by  every  means  he  can  devise ;  and 
hence  his  investigations  do  not  cease  with  an  examination  of  the  external, 
macroscopic  characters,  but  must  be  extended  to  the  finer  microscopic  and 
histological  as  well.  In  numerous  instances  paleontology  has  anticipated 
zoology  and  botany  by  important  histological  discoveries ;  in  the  brauch  of 
vertebrate  comparative  anatomy,  for  example,  through  the  exhaustive  study 
of  conservable  hard  parts,  such  as  the  teeth,  skeleton,  dermal  covering,  etc., 
this  science  has  been  elevated  to  its  present  high  Standard  chiefly  by  paleon- 
tologists  (Cuvier,  Owen,  Huxley,  H.  von  Meyer,  Rütimeyer,  Marsh,  Cope, 
Osborn  and  others).  The  principle  of  correlation  of  parts,  first  applied  with 
such  eminent  success  by  Cuvier,  according  to  which  all  parts  of  an  organism 
stand  in  certain  fixed  relationships  to  one  another,  so  that  one  organ  cannot 
Vary  without  a  corresponding  Variation  taking  place  in  the  others,  is  now 
worked  out  not  only  for  the  whole  group  of  vertebrates,  but  for  invertebrates 
as  well ;  and  its  elaboration  is  such  that  frequently  a  single  bone,  tooth, 
plate,  carapace,  shell-fragment  and  the  like,  is  sufficient  for  us  to  form  a 
tolerably  accurate  concept  of  the  entire  creature.  It  is  therefore  clear  that 
in  so  far  as  paleontology  has  to  deal  with  the  study  and  Classification  -of  fossil 
organisms,  it  is  no  other  than  a  part  of  zoology,  comparative  anatomy  and 
botany,  and  hence  may  be  very  properly  divided  into  Paleozoology  and  Faleo- 
lotany.  Paleontology  has  vastly  increased  the  subject  -  matter  of  the  two 
biological  sciences,  has  filled  up  innumerable  gaps  in  the  system,  and  has 
infinitely  enriched  our  knowledge  of  the  variety  and  complexity  of  plant  and 
animal  Organisation.  In  almost  every  class  of  both  kingdoms  where  preserva- 
tion is  possible,  the  number  of  fossil  forms  cohsiderably  exceeds  the  recent. 
A  natural  Classification  of  the  Foraminifera,  sponges,  corals,  echinoderms, 
moUusks,  vertebrates,  and  of  the  vascular  cryptogams,  cycads  and  conifers, 
would  be  utterly  inconceivable  without  taking  paleontological  evidence  into 
account,  since  in  certain  classes  (brachiopods,  cephalopods,  reptiles,  mammals) 
the  number  of  extinct  fossil  forms  may  be  ten,  a  hundred,  or  even  a  thousand- 
fold  greater  than  the  living,  and  this  proportion  is  steadily  increasing  in 
favour  of  paleontology,  as  fresh  discoveries  are  made  in  various  parts  of  the 
World. 

Paleontology  and  Geology. — Although  as  a  biological  science  paleon- 
tology does  not  differ  essentially  from  botany  and  zoology,  yet  its  connection 
with  geology  is  none  the  less  intimate,  and  consequently  it  has  been  cultivated 
quite  as  assiduously  by  geologists  as  by  biologists.  The  material  is  brought 
to  light  almost  wholly  by  geologists  or  by  geological  collectors,  who  obtain  it 
from  the  stratified  rocks  of  the  earth's  crust — that  is  to  say,  rocks  which  have 
been  formed  by  the  subaqueous  deposition  of  sediment,  or  have  been  built  up 
from  detritus  on  dry  land  by  aerial  agency.  The  distribution  of  fossils 
throughout  stratified  rocks  is  by   no  means  promiscuous,  neither  do  all  rocks 


4  ELEMENTS  OF  PALEONTOLOGY 

contain  the  same  species ;  but  on  the  contrary,  each  separate  stratigraphical- 
complex,  and  frequently  even  single  beds  and  layers,  are  characterised  by 
certain  particular  assemblages  of  fossils.  The  older  the  rock,  the-more  strikingly 
different  from  recent  organisms  are  its  fossil  remains  ;  the  younger  the  forma- 
tion,  the  greater  is  their  resemblance.  Now,  since  experience  shows  that 
contemporaneous  deposits  which  have  been  laid  down  under  similar  conditions 
(as,  for  example,  in  salt  or  in  fresh  water)  contain  identical  or  at  least  very 
similar  fossils,  the  latter  furnish  us  with  an  infallible  guide,  taken  together 
with  the  local  stratigraphic  succession,  for  determining  the  relative  age  of  a 
given  formation.  Furthermore,  a  knowledge  of  the  fossils  occurring  in  homo- 
taxial  deposits  enables  us  to  reconstruct  the  various  paleofaunas  and  paleo- 
floras  which  have  existed  on  our  planet  at  different  periods  in  its  history. 
Having  determined  the  chronological  succession  of  the  clastic  rocks  by  means 
of  their  superimposition  and  their  characteristic  or  index-fossils,  they  may  be 
divided  up  into  still  smaller  series,  each  one  of  which  is  characterised  by  a 
particular  assemblage  of  organic  remains.  In  the  main,  then,  paleontology  is 
the  ultimate  foundation  of  historical  geology. 

Excluding  the  oldest  metamorphic  rocks  (gneiss,  mica  schists,  phyllites, 
etc.)  which  are  destitute  of  fossils,  and  concerning  whose  origin  there  is  still 
great  difFerence  of  opinion,  the  total  thickness  of  the  sedimentary  rocks 
amounts  to  20,000 — 30,000  metres.  The  building  up  of  this  prodigious 
pile  of  rock  must  have  extended  over  an  inconceivably  long  time,  whose  dura- 
tion  cannot  even  approximately  be  estimated,  since  we  are  without  data  as 
to  the  rate  of  deposition  in  former  periods,  and  since  the  beginning,  culmina- 
tion  and  end  of  geological  epochs  cannot  be  correlated  with  astronomical 
events. 

Since,  however,  the  earth  has  been  inhabited  in  former  times  by  very 
different  creatures  from  those  now  living ;  since  successive  paleofaunas  and 
paleofloras  follow  one  another  everywhere  in  the  same  order ;  and  since, 
furthermore,  in  certain  formations  the  greater  part  or  even  the  total  number 
of  species  appear  and  disappear  in  a  body,  so  that  one  fauna  or  flora  is 
replaced  almost  in  its  entirety  by  the  next  following ;  it  is  obvious  that  the 
sedimentary  rocks  may  be  subdivided  into  a  number  of  longer  and  shorter 
time  measures,  which  may  be  designated  by  particular  names.  The  beginning 
and  end  of  such  periods  (group,  System  or  formation,  series  or  section,  stage, 
Zone  or  bed)  is  usually  indicated  by  local  interruptions  in  the  deposition, 
occasioned  by  variations  in  sea-level,  volcanic  eruptions,  or  by  other  causes  ; 
and  such  disturbances  are  usually  accompanied  by  changes  in  the  flora  and 
fauna.  The  now  generally  accepted  subdivision  of  the  secondary  rocks  is 
represented  in  the  table  on  page  5,  in  which  it  should  be  noted  that  only  the 
first  three  columns  are  of  universal  significance,  while  the  last  two  apply  only 
to  European  countries. 

The  rocks  of  the  Archaean  Group  amount  to  40,000—60,000  metres  in 
thickness.  They  belong  to  the  oldest  and  longest  period  in  the  history  of 
our  planet,  and  are  remarkable  for  their  schistose  and  crystalline  structure,  as 
well  as  for  the  total  absence  of  fossils.  In  order  of  stratigraphy,  gneiss  com- 
prises  for  the  most  part  the  oldest ;  mica,  chlorite,  and  talc-schists  the  middle  ; 
and  phyllites  (primitive  schists)  the  youngest  division  of  this  group.  The 
so-called  fossil  organism,  Eozoon,  occurring  in  gneiss,  has  been  proved  to  be  of 
inorganic  nature. 


■ 

INTRODUCTION                                                       5 

Eras 

Periods 

1 

i              Epochs              (Etages) 

P4 

1 

Quarternary 
System 

Alluvium 

Recent  Deposits 

Diluvium 
(Pleistocene) 

Postglacial  Series 
Glacial 
Preglacial        ,, 

Tertiary  System 

1 

o 

Pliocene 

Upper  or  Siciliaii                           (öicilien) 
Middle  or  Astiaii                            (Astieii) 
Lower  or  Plaisaneiaii                     (Messinien) 

Miocene 

Pontian  iSeries                                (Pontien) 
Sarniatian  ,,                                    (Sannatien) 
Tortonian   ,,                                    (Tortonien) 
Helvetian  „                                    (Helvetien) 
Burdigalian  Series                         (Burdigalien) 
Aquitanian       ,,                            (Aquitanien) 

Oligocene 

Upper  or  Rupelian                       (Stanipien) 
Lower  or  Lattorfian                      (Tongrien) 

Eocene 

Bartonian  Series                            (Bartonien) 
Parisian         ,,                               (Lutetien) 
Ypresian        „                               (Ypresien) 
Landeniau     ,,                                 (Landenien) 

Mesozoic  Group 

Cretaceous 
System 

Upper  Cretaceous 

Danian  Series                                 (Danien) 
Senonian   ,,                                     (Senonien) 
Turonian  ,,                                    (Turonien) 
Cenomanian  Series                       (Cenomanien) 

Lower  Cretaceous 

Gault  Series                                   (Albien) 
Ai)tian  and  Urgonian  Series        (Aptien,  Urgonien) 
Barremian  Series                          (Barremien) 
Xeocomian  and  Wealden  Series  (Neocomien) 

Jurassic  System 

Upper  Jurassic 
(Malm) 

Tithonian  and  Portland  Series    (Portlandien) 
Kinimeridgian                      ,,         (Kimmeridgien) 
Corallian                               ,,         (Sequanien) 
Oxfordian                             „        (Oxfordien) 
Kellaway                              ,,        (Callovien) 

Middle  Jurassic 
(Dogger) 

Bath  or  Great  Oolite  Series         (Bathonien) 
Bajeux  or  Inferior  Oolite  Series  (Bajocien) 

Lower  Jurassic 
(Lias) 

Toarciaii  Sfiies                               (Toarcien) 
Charmouthiau  Series                     (Charmouthien) 
Sinemurian           ,,                        (Sinemurien) 
Hettangian           ,,                        (Hettangien) 
Rhaetic  Stage                                (Rhaetien) 
Noric            „                                   (Norien) 
Carinthian  ,,                                   (Carnien) 

Triassic  System 

Upper  Triassic 
(Keuper) 

Middle  Triassic 
(Muschelkalk) 

Ladinian  Series                              (Ladinlen) 
Virglorian     ,,                                  (Virglorien) 

Lower  Triassic 
(Bunter  Sandstein) 

Werfenian  series                           <'äyEj°' 

^^Bu 

Permian  System 
(Dyas) 

Zechstein 
Rothliegendes 

Thuringian  Series                          (Thuringien) 
Saxonian  or  Penjabian                  (Saxonien) 
Artinsk  or  Autunian                     (Autunien) 

Carboniferous 
System 

Coal  Measures 

Uralian  or  Steplianian                  (Ouralien) 
Muscovian  or  Westphalian           (Moscovien) 

Lower  Carboniferous 
(Culm) 

Dinantian  Series  or  Culni            (Dinantien) 

Devonian 
System 

Upper  Devonian 

Famennian  Series                          (Famennien) 
FrasniaTi         ,,                              (Frasnien) 

Middle  Devonian 

Givetian         ,,                              (Givetien) 
Bifelian  Series                                (Eifelien) 

Lower  Devonian 

Coblenzian  Series                           (Coblentzien) 
Gedinnian      ,,                                (Gedimiien) 

Silurian  System 

Silurian 

Ludlow  Series                            ^ 

Wen  lock     „                                   WGothlandien) 

Llandovery  Series                      j 

Ordovician 
(Lower  Silurian) 

Bala  or  Caradoc  Series              ) 

Llandeilo                 „                   WOrdovicien) 

Arenig                      „                   ) 

Cambrian 
System 

Upper  Cambrian 

is'Är'f^        (rot»"-™) 

Middle  Cambrian 

Menevian  Series                            (Acadien) 

Lower  Cambrian 

Harlech  Series                               (Georgien) 

Arch- 
aean 
Group 

Primitive  Schist 

System 
Gneiss  System 

Phyllite  (Primitive  Schists, 
Mica  and  Chlorite  Schists, 
etc.) 
1                     Gneiss 

Precambrian  Series                       (Algonkien) 

6  ELEMENTS  OF  PALEONTOLOGY 

The  Faleozoic  or  Primarij  Group  comprises  the  Cambrian,  Ordovician, 
Silurian,  Devonian,  Carboniferous  and  Permian  Systems,  each  of  which  is 
made  up  of  a  great  number  of  series,  stages  and  zones.  In  the  Cambrian 
crustaceans,  trilobites,  brachiopods  and  worms  predominate,  associated  with  a 
few  echinoderms,  coelenterates,  sponges  and  poorly  preserved  algae.  In  the 
Silurian  system  most  classes  of  the  animal  kingdom  are  represented  with  the 
exception  of  amphibians,  reptiles,  birds  and  mammals,  while  the  flora  still 
consists  of  algae.  Marine  invertebrates  are  very  abundant,  especially  crus- 
taceans, moUusks,  echinoderms  and  coelenterates,  while  only  a  few  frag- 
mentary  fish-remains  indicate  the  presence  of  vertebrates.  All  the  species 
and  nearly  all  the  genera  have  since  become  extinct,  and  belong  for  the  most 
part  to  extinct  families  and  Orders.  During  the  Devonian,  Carboniferous  and 
Permian  Systems,  the  same  classes  of  animals  continue  as  a  body,  but  are 
represented  by  frequently  different  families  and  genera.  Fishes  develop  a  great 
variety  of  forms  in  the  Devonian,  amphibians  (Stegocephalia)  make  their 
appearance  in  the  Carboniferous,  and  reptiles  in  the  Permian.  The  flora 
consists  chiefly  of  vascular  cryptogams,  together  with  a  few  conifers  and 
cycads. 

The  Mesozoic  Group  comprises  three  Systems — the  Triassic,  Jurassic  and 
Cretaceous.  Many  of  the  widely  distributed  Paleozoic  types  (Tetracoralla, 
graptolites,  crinoids,  cystids,  blastoids,  brachiopods,  trilobites)  have  either  wholly 
or  in  greater  part  disappeared,  while  others  (cephalopods,  lamellibranchs,  sea- 
urchins)  are  replaced  by  very  different  genera  and  families.  Vertebrates  are 
remarkable  for  the  gigantic  size  attained  by  amphibians  (Labyrinthodonta)  and 
many  reptiles,  as  well  as  for  the  wonderful  variety  of  the  latter.  Birds  appear 
for  the  first  time  in  the  Upper  Jurassic  (Archaeopteryx),  and  mammals 
towards  the  close  of  the  Triassic,  being  represented  by  diminutive,  probably 
marsupial  types.  During  the  Triassic  and  Jurassic  periods,  vascular  crypto- 
gams, conifers  and  cycads  remain  the  dominant  plant-forms,  dicotyledons  not 
occurring  until  the  middle  Cretaceous. 

The  Cenozoic  Group  comprises  the  Tertiary  and  post-Tertiary  or  Quaternary 
Systems.  Among  the  invertebrates,  ammonites,  belemnites,  Rudistae  and 
most  of  the  Crinoidea  have  now  passed  away.  Amphibians  and  reptiles  have 
greatly  declined,  and,  like  the  invertebrates,  are  represented  by  still  living 
Orders.  On  the  other  band,  birds,  and  particularly  mammals,  attain  a 
wide  distribution ;  the  latter  class  branches  out  in  such  manifold  variety,  and 
experiences  such  rapid  development  during  Cenozoic  time,  that  it  alone 
furnishes  us  with  the  principal  index-fossils  of  this  era.  From  now  on  the 
flora  consists  chiefly  of  dicotyledonous  plants. 

Paleontology  and  Physical  Geography.  —  Not  only  do  fossils  con- 
stitute  the  very  foundation  of  historical  geology,  but  they  furnish  us  in 
addition  with  valuable  inform'ation  respecting  the  origin  of  the  rocks  in 
which  they  occur,  the  former  distribution  of  land  and  water,  climatal 
conditions,  and  the  facts  of  geographical  distribution  in  former  periods.  By 
means  of  analogy  with  recent  species  we  are  able  in  most  cases  readily  to 
determine  whether  fossil  forms  pertain  to  land,  fresh,  brackish  or  salt  water 
species,  whence  it  is  apparent  under  what  conditions  the  strata  were  deposited. 
The  distribution  of  marine  and  fresh-water  formations  helps  us  to  certain 
conclusions  respecting  the  extent  of  former  seas  and  land  areas.  Deep-sea, 
shallow  water,  and  littoral  deposits  are  readily  distinguishable  by  means  of 


INTRODUCTION  7 

their  fossil  organisms.  By  fossils,  also,  even  the  climatal  conditions  of 
former  periods  are  indicated  with  great  fidelity.  The  luxurious  and  uniform 
development  of  cryptogams  over  the  face  of  the  globe  during  Carboniferous 
time  presupposes  a  warm,  moist  climate,  little  varying  with  latitude ;  tropical 
dicotyledons  occurring  in  the  Cretaceous  and  Tertiary  deposits  of  Greenland,or 
coral-reefs  extending  into  high  latitudes  during  the  Paleozoic  era,  prove  with 
equal  certainty  the  prevalence  of  a  milder  climate  and  higher  oceanic  temperature 
in  earlier  times ;  while  again,  the  remains  of  reindeer,  the  lemming,  musk-ox, 
polar  fox,  and  other  arctic  animals  in  the  diluvium  of  Central  Europe  testify 
to  a  period  of  glaciation  with  reduced  mean  annual  temperature. 

The  geographical  distribution  of  fossil  organisms  proves  that  the  regions 
and  provinces  occupied  by  recent  plants  and  animals  are  to  a  certain  extent 
identical  with  those  existing  in  the  Tertiary,  and  that  life  has  been  subject  to 
the  same  distributional  laws  in  the  past  as  in  the  present.  Nearly  all  recent 
forms  are  the  obvious  descendants  of  extinct  creatures  which  formerly 
occupied  the  same  region.  For  example,  the  fossil  mammals,  birds  and 
reptiles  of  Diluvial  time  in  Europe,  Asia,  Australia,  North  and  South  America, 
are  scarcely  distinguishable  from  forms  now  inhabiting  the  same  continents. 
The  ancestral  homes  of  marsupials  and  edentates  were  perpetuated  in 
Australia  and  South  America  until  as  recently  as  the  Diluvial  epoch,  and 
during  the  later  Tertiary,  Europe,  Asia  and  America  formed  but  a  single 
zoological  province,  inhabited  by  the  ancestors  of  forms  now  living  in  the 
northern  hemisphere.  An  understanding  of  the  physical  conditions  which 
have  governed  the  perpetuation  of  recent  plants  and  animals  in  their  respective 
provinces  (succession  of  similar  types)  would  be  utterly  impossible  without  a 
knowledge  of  their  distribution  in  former  times.  In  like  manner,  our  know- 
ledge  of  the  distribution  of  land  and  water,  of  prevailing  climatal  conditions, 
oceanic  currents,  etc.,  of  earlier  periods  depends  chiefly  upon  evidence  derived 
from  fossils. 

Paleontology  and  Embryology. — To  trace  the  development  of  living 
plants  and  animals  through  all  stages  from  the  one-celled  egg  onward  to 
final  dissolution,  is  the  task  of  Embryology  and  Ontogeny.  At  the  present 
moment,  botanists  and  zoologists  are  devoting  their  most  scrutinising  attention 
to  embryological  investigations,  which  latter  accordingly  exert  a  powerful 
influence  on  the  progress  of  biology,  and  particularly  on  the  Classification. 
The  fact  that  every  individual,  species  and  genus  of  a  whole  group  of  plants 
and  animals  passes  through  nearly  the  same  course  of  development,  at  least 
in  the  primary  stages,  and  that  all  embryos  belonging  to  a  given  order  or 
class  resemble  one  another  so  closely,  up  to  a  certain  stage,  that  they  cannot 
be  told  apart,  has  revealed  unexpected  affinities  among  forms  differing  very 
considerably  in  the  adult  stage.  Cirripedes,  for  example,  which  were  formerly 
mistaken  for  shell-bearing  mollusks,  develop  from  the  same  Nauplius-larvae 
as  the  Copepoda,  Branchiopoda  and  Ostracoda,  although  the  mature  individuals 
belonging  to  these  Orders  of  crustaceans  possess  but  little  common  resemblance. 
Likewise,  the  whole  group  of  vertebrate  embryos  can  hardly  be  distinguished 
from  one  another  in  the  earliest  stages,  and  only  very  gradually  assume  the 
characteristic  features  pertaining  to  class  and  order. 

The  results  of  embryological  inquiry  have  a  most  important  bearing  on 
paleontology.  Numerous  fossil  forms  are  known,  which,  in  comparison  with 
recent  related  organisms,  exhibit  embryonic,  or  at  least  larval  or  adolescent 


8  ELEMENTS  OF  PALEONTOLOGY 

characteristics.  Examples  of  such  primitive  or  emhryonic  fypes  are  especi- 
ally  common  in  vertebrates,  for  the  reason  that  here  the  skeleton  becomes 
ossified  very  early  in  life,  and  hence  the  immature  stages  of  the  recent  can  be 
directly  compared  with  adult  fossil  forms.  Now,  Observation  has  shown  that 
in  most  of  the  older  fossil  fishes  and  reptiles,  the  vertebral  column  never 
passed  beyond  an  embryonic  stage,  but  remained  in  a  cartilaginous  or 
incompletely  ossified  condition  through  life.  The  Paleozoic  amphibians 
(Stegocephalia)  probably  breathed  by  means  of  both  gills  and  lungs  through- 
out  life,  whereas  most  recent  amphibians  lose  their  gills  comparatively  early 
(Caducibranchia),  and  breathe  wholly  by  lungs.  Many  fossil  reptiles  and 
mammals  retain  certain  skeletal  peculiarities  permanently,  while  allied  recent 
forms  exhibit  them  only  in  embryonic  stages.  The  skull  in  most  of  the  older 
fossil  reptiles  and  mammals  closely  corresponds  in  form  and  structure  with 
that  in  embryos  of  recent  related  types.  In  the  oldest  fossil  artiodactyls 
the  palm-bones  are  all  completely  separated,  while  in  recent  ruminants  this 
division  continues  only  during  the  embryonic  stage,  being  followed  by  a 
fusion  of  the  two  median  metapodals,  together  with  a  reduction  of  the  laterals. 
Among  invertebrates,  also,  fossil  embryonic  types  are  by  no  means  uncommon. 
The  Paleozoic  Belinuridae  find  their  counterpart  in  the  larvae  of  the  common 
Limulus ;  many  fossil  sea-urchins  are  characterised  by  linear  ambulacra,  while 
recent  related  forms,  although  developing  petaloid  radii  in  the  adult  stage, 
pass  through  the  linear  phase  during  adolescence.  Many  fossil  crinoids  re- 
semble  the  young  of  the  living  genus  Antedon ;  and,  according  to  Jackson, 
recent  echinoids,  oysters  and  pectens  exhibit  in  their  nepionic  stages  certain 
characters  peculiar  to  the  adults  of  Paleozoic  genera. 

The  so-called  fossil  generalised  or  comprehensive  types,  which  unite  in  one  and 
the  same  form  characters  which,  in  geologically  later,  or  recent  descendants, 
have  become  distributed  among  different  genera  and  families,  are  in  reality 
merely  primitive  or  immature  types  which  have  stopped  short  of  the  higher 
differentiation  attained  by  their  descendants.  Generalised  types  always 
precede  more  highly  specialised ;  and  properties  that  were  originally  distri- 
butive among  older  forms  are  never  reunited  in  geologically  younger  species 
or  genera.  Trilobites,  amphibians  and  reptiles  of  the  Paleozoic  and  Mesozoic 
eras,  and  early  Tertiary  mammals  belong  almost  exclusively  to  the  category 
of  generalised  types. 

In  certain  groups  of  vertebrates,  and  especially  of  mammals  (Ungulata, 
Carnivora),  the  chronological  succession  of  genera  is  so  closely  paralleled  by 
the  successive  stages  of  development  in  the  life-history  of  their  descendants, 
that  to  a  certain  extent  the  ontogeny  of  the  individual  is  a  representment  of 
a  long  chronological  series  of  fossil  forms.  This  truth  furnishes  a  strong 
foundation  for  the  hiogenetic  law,  enunciated  in  various  terms  by  GeofFroy  St. 
Hilaire,  Serres,  Meckel,  Fritz  Müller  and  others,  and  recently  more  precisely 
formulated  by  Haeckel,  as  follows :  The  developmental  history  or  ontogeny 
of  an  individual  is  merely  a  short  and  simplified  repetition  or  recapitulation  of 
the  slow  (perhaps  extending  over  thousands  of  years)  process  of  evolution  of 
the  species  and  of  the  whole  brauch. 

The  biogenetic  law  has  since  been  found  to  hold  true  not  only  for  verte- 
brates, but  also  for  invertebrates,  including  even  wholly  extinct  types.  In 
ammonites,  for  instance,  the  primary  or  innermost  whorls  always  difFer  frora 
the  outer  in  their  greater  simplicity  of  suture,  and  in  their  lesser  ornamenta- 


INTEODUCTION  9 

tioii.  Very  ofteii  a  correspondence  is  observable  with  geologically  older  forms  ; 
and  it  is  a  well-known  fact  that  all  ammonites  pass  through  early  stages  whicli 
resemble,  at  least  so  far  as  chambering  of  the  shell  is  concerned,  Paleozoic 
goniatites.  A  comparison  of  the  inner  whorls  of  an  ammonite  with  its  corre- 
sponding  goniatitic  form,  or  with  older  ammonites,  seldom  fails  to  reveal 
ties  of  kinship  not  otherwise  discernible.  Beecher  has  shown  that  nearly 
every  stage  in  the  development  of  arm-supports  in  recent  brachiopods  corre- 
sponds  to  conditions  of  the  adult  in  some  fossil  genus ;  and  further,  that  the 
chronological  succession  of  the  latter  is  to  a  certain  degree  identical  with  the 
successive  ontogenetic  stages  of  recent  forms. 

The  relation  of  rudimentary  or  degradational  organs  occurring  in  recent  forms 
to  those  of  the  fossil  ancestors  of  the  latter  is  of  extreme  significance.  By 
rudimentary  organs  are  meant  certain  structures  (as,  for  example,  limbs, 
parts  of  limbs,  organs  of  sense,  respiration,  digestion,  reproduction,  etc.), 
which  are  still  indicated  by  atrophied  remains,  but  whose  physiological 
functions,  and  hence  their  Utility  to  the  organism,  have  wholly  disappeared. 
Rudimentary  organs  are,  as  a  rule,  either  normally  developed  in  an  embryonic 
stage,  or  at  least  more  strongly  than  in  the  adult  individual,  owing  to  a 
process  of  degeneration,  or  retrogressive  development.  The  fossil  progenitors 
of  forms  possessing  vestigial  structures  are  almost  always  characterised  by 
a  füll  development  of  the  respective  parts.  The  lateral  metacarpals  and 
metatarsals  in  the  horse  and  most  ruminants,  for  example,  are  indicated  only 
by  rudimentary  side-splints  ;  but  in  an  embryonic  stage  they  are  much  more 
strongly  developed,  and  in  related  fossil  forms  they  occur  as  normal  bones, 
carrying  toes  like  the  other  metapodals,  and  serving  for  locomotion  and 
Support.  The  wrist  and  metacarpal  bones  in  birds  have  also  sufFered  degenera- 
tion, as  is  evident  from  a  comparison  with  embryos  and  wdth  older  forms 
(Archaeopteryx),  which  exhibit  a  much  higher  development.  In  like  manner, 
the  teeth  of  birds  have  also  become  degenerated.  In  only  a  few  forms 
(parrots,  ostriches)  are  faint  dental  ridges  discernible  during  embryonic  stages  ; 
but  in  all  known  Mesozoic  birds  the  teeth  are  well  developed  and  remain 
functional  throughout  life.  Similarly,  teeth  are  developed  during  embryonic 
stages  in  the  baleen  whale,  but  subsequently  become  atrophied  ;  while  in  the 
older  fossil  Cetacea  teeth  are  always  present.  Other  instances  of  this 
nature  are  to  be  met  with  in  great  profusion,  both  among  vertebrates  and 
invertebrates. 

The  biogenetic  law  is,  however,  not  infrequently  obscured,  for  the  reason 
that  two  closely  related  forms  may  not  develop  in  exactly  the  same  manner  ; 
embryos  of  the  one  type  may  be  afFected  by  peculiar  accelerating  impulses 
which  are  not  shared  by  those  of  the  other,  and  in  consequence  the  first  may 
pass  through  certain  stages  very  rapidly,  or  may  even  omit  them  altogether. 
In  this  way  the  historical  or  palingenetic  record  contained  in  the  development 
of  every  individual  may  be  to  a  large  extent  veiled,  suppressed  or  rendered 
unintelligible ;  and  this  phenomenon  of  inexact  parallelism  (coenogenesis)  is 
especially  common  in  highly  differentiated  types,  where  the  embryo  passes 
through  a  multitude  of  phases. 

Paleontology  and  Phylogeny. — While  conceding  that  by  means  of 
embryological  investigations  zoologists  and  botanists  are  able  to  trace  the 
gradual  development  and  differentiation  of  an  organism  through  all  its  various 
stages,  and  thereupon  to  construct  a  tree  of  descent  (phylogeny)  founded  upon 


10  ELEMENTS  OF  PALEONTOLOGY 

the  successive  phases  of  grovvth,  nevertheless  such  hypothetical  genealogies 
can  only  be  relied  upon  as  truthful  when  they  are  substantiated  by  paleonto- 
logical  facts.  And  only  in  cases  where  the  difFerent  ontogenetic  stages  are 
represented  by  corresponding  fossil  primitive  or  generalised  types,  which 
appear  in  the  same  chronological  order,  and  clothe  the  supposititious  ancestral 
tree  with  real  forms,  can  the  truthfulness  of  the  latter  be  said  to  have  been 
established.  This  requirement  paleontology  is  from  the  nature  of  things 
unable  to  satisfy  except  in  a  few  instances ;  but  a  multitude  of  other  facts 
testifies  to  the  blood-kinship  between  morphologically  similar  fossil  and  recent 
organisms,  and  points  to  the  direct  descent  of  the  younger  from  the  older 
forms. 

Geology  proves  conclusively  that  of  the  numerous  floras  and  faunas  which 
lie  buried  in  the  rocks,  those  which  are  most  nearly  of  the  same  geological 
age  bear  the  greatest  resemblance  to  each  other.  It  often  happens  that  species 
and  genera  occurring  in  a  given  formation  reappear  in  the  next  following  with 
scarcely  any  perceptible  changes,  so  that  the  doctrine  of  the  gradual  trans- 
formation  and  transmutation  of  older  forms  is  irresistibly  forced  upon  one, 
while  the  faunas  and  floras  of  later  periods  assert  themselves  as  the  obvious 
descendants  of  the  more  ancient.  Other  weighty  evidence  for  the  progressive 
evolution  of  organisms  is  afforded  by  fossil  transitional  series,  of  which  a 
considerable  number  are  known,  notwithstanding  the  imperfection  of  the 
paleontological  record.  By  transitional  series  are  meant  a  greater  or  less 
number  of  similar  forms  occurring  through  several  successive  horizons,  and 
constituting  a  practically  unbroken  morphic  chain.  Often  the  differences 
between  individuals  belonging  to  diff'erent  periods  are  so  slight  that  we  can 
hardly  assign  to  them  the  value  of  a  variety.  But  let  a  number  of  such 
mutations  occur  in  succession,  the  end-members  of  the  series  become  finally 
so  divergent  as  to  constitute  distinct  species  and  genera.  The  most  striking 
and  most  numerous  examples  of  transitional  series  naturally  occur  in  types 
peculiarly  well  fitted  for  preservation,  such  as  mollusks,  brachiopods,  sea- 
urchins,  corals  and  vertebrates.  Particularly  remarkable  among  mollusks 
are  the  closely  linked  transitional  series  in  ammonites.  Among  vertebrates 
transmutation  proceeded  far  more  rapidly  than  among  invertebrates,  and 
accordingly,  the  successive  members  of  a  series  are  usually  so  divergent  as  to 
require  their  assignment  to  separate  genera. 

With  increasing  abundance  of  paleontological  material,  the  more  numerous 
and  more  complete  are  the  series  of  intermediate  forms  which  are  brought  to 
light.  But  the  more  extended  our  knowledge  of  transitional  series  the  greater 
is  the  difficulty  we  encounter  in  defining  our  conception  of  species.  While  the 
older  disciples  of  the  Linnean  and  Cuvierian  schools  contended  that  each 
separate  species  was  created  with  a  certain  definite  sum  of  fixed  characters, 
and  remained  incapable  of  any  extensive  modifications ;  on  the  other  band, 
those  holding  to  the  Darwinian  theory  of  evolution  look  upon  varieties, 
species,  subgenera,  genera,  families,  Orders,  classes  and  phyla  merely  as 
arbitrary  yet  useful  and  convenient  distinctions,  corresponding  to  the  state  of 
our  information  at  the  present  time ;  it  being  assumed  that  by  means  of 
gradual  transmutation  during  the  course  of  ages  all  organisms  have  become 
evolved  from  a  single  primitive  cell,  or  from  a  few  primitive  types. 

According  to  the  Linne-Cuvier  doctrine,  a  species  is  composed  of  individuals 
which  are  directly  descended  from  one  another,  or  from  common  ancestors, 


INTRODUCTION  13 

and  which  resemble  their  progenitors  as  much  as  they  resemble  each  oti^es 
Membeis  of  one  and  the  same  species  interbreed,  but  individuals  belongin^ 
to  different  species  do  not  cross,  or  when  they  do,  produce  infertile  or 
iraperfectly  fertile  offspring. 

According  to  the  theory  of  descent  no  sharp  specific  distinctions  can  be 
drawn,  but  all  individuals  are  assigned  to  the  same  species  which  share  a 
number  of  essential  features  in  common,  and  which  are  not  connected  with 
neighbouring  groups  by  means  of  intermediate  types.  It  is  piain  that  this 
definition  is  open  to  considerable  laxity  of  interpretation,  and  inasmuch  as 
the  direct  descent  of  individuals  belonging  to  a  given  species  cannot  always  (in 
paleontology  never)  be  determined  on  experimental  grounds,  systematists 
are  rarely  agreed  in  regard  to  the  precise  limitations  of  species,  genera  and 
families. 

The  doctrine  of  the  invariability  of  species  received  powerful  support  from 
the  cataclysmic  theory  of  Cuvier,  which  maintained  that  each  period  in  the 
earth's  history  is  marked  by  distinctively  characteristic  faunas  and  floras  ;  that 
no  species  is  common  to  two  successive  periods  ;  that  tremendous  convulsions 
of  nature  (catadysms)  occurred  at  the  close  of  each  cycle,  and  annihilated  the 
whole  organic  world  ;  and  that  by  means  of  special  creative  acts,  the  renovated 
earth  became  time  and  again  populated  with  new  animals  and  plants  which  bore 
absolutely  no  connection  with  either  previous  or  subsequently  introduced  types. 

Cuvier's  cataclysmic  theory  raay  be  regarded  at  the  present  day  as  com- 
pletely  overthrown,  inasmuch  as  the  modern  school  of  geology,  following  the 
leadership  of  Sir  Charles  Lyell,  has  demonstrated  conclusively  that  the  earth 
has  proceeded  from  one  stage  to  another  during  the  course  of  its  development 
only  with  the  utmost  slowness  ;  that  the  same  forces  and  laws  which  regulato 
the  World  of  to-day  have  operated  likewise  in  primeval  times  ;  and  that 
geological  periods  are  by  no  means  abruptly  set  off  from  one  another,  but  are 
linked  together  by  innumerable  transitional  stages. 

The  theory  of  the  descendant  origin  of  organic  forms,  which  was  advanced 
as  early  as  1802  by  J.  B.  Lamarck  and  Geoffroy  St.  Hilaire,  and  was  supported 
by  Goethe,  Oken  and  Meckel  in  Germany,  kept  winning  continually  more 
adherents,  yet  it  was  not  until  the  latter  half  of  the  nineteenth  Century  that 
its  universal  significance  was  insisted  on  by  Charles  Darwin  and  his  school. 

Paleontology,  as  already  remarked,  contributes  a  great  deal  of  extremely 
weighty  evidence  in  favour  of  the  theory  of  descent ;  the  series  of  intermediate 
forms,  often  traceable  through  several  successive  formations ;  the  presence  of 
primitive  and  generalised  types ;  the  parallelism  between  ontogeny  and  the 
chronological  succession  of  related  fossil  forms ;  the  similarity  between  floras 
and  faunas  of  approximately  the  same  age ;  the  correspondence  in  the 
geographica!  distribution  of  recent  organisms  with  that  of  their  progenitors ; 
and  a  host  of  other  facts  are  explicable  only  by  means  of  the  theory  of  descent. 

The  causes  of  Variation  and  transformation  were  attributed  by  Lamarck 
chiefly  to  the  use  and  disuse  of  organs ;  secondly,  to  the  effect  of  changes  in 
external  conditions  ;  and  lastly,  to  a  supposed  inherent  tendency  toward 
Variation  and  perfection  existing  in  each  individual.  According  to  Lamarck, 
new  characters  brought  about  by  these  influences  are  transmitted  to  descend- 
ants  through  inheritance,  and  become  permanently  established  in  the  race. 
Geoffroy  St.  Hilaire  maintained  the  same  principles  on  the  whole,  but  ascribed 
the  chief  causes  of  Variation  of  species  to  the  infiuence  of  environment. 


12  ELEMENTS  OF  PALEONTOLOGY 

The  Darwinian  theory  of  natural  selectioii  is  based  upon  the  property 
common  to  all  organisms  of  acquiring  ancestral  characteristics  through  heredity, 
and  of  transmitting  them  in  turn  to  their  progeny  ;  and  also  on  the  adapta- 
bility  of  organisms  to  particular  external  conditions,  by  means  of  which 
variations  are  brought  about.  Since  in  the  struggle  for  existence  only  those 
individuals  which  are  the  best  adapted — that  is  to  say,  those  possessing  the 
most  advantageous  modifications — survive,  nature  is  continually  exercising, 
according  to  Darwin,  a  most  rigorous  selection  which  operates  toward  the 
increase  and  perfection  of  useful  variations.  Through  the  constant  accumula- 
tion  of  originally  slight  yet  serviceable  modifications,  and  through  the  perpetual 
transmission  of  the  same  from  one  generation  to  another,  there  are  produced 
first  of  all  new  varieties,then  species,  and  eventually  genera,  families  and  Orders. 
The  zoological  and  botanical  classifications  are,  according  to  Darwin,  merely  an 
expression  of  genealogical  facts,  exhibiting  the  remoter  and  closer  ties  of 
consanguinity  which  exist  among  difFerent  organic  forms. 

Darwin's  explanation  of  the  origin  of  species  by  the  addition  of  the 
agency  of  natural  selection  to  the  Lamarckian  factors  of  Variation  and 
inheritance  found  in  Wallace,  Huxley,  Haeckel  and  others,  zealous  and 
ingenious  supporters,  although  on  other  sides  it  encountered  vehement 
Opposition.  Moritz  Wagner  regarded  free  intercrossing  as  an  insurmountable 
obstacle  to  the  establishment  of  new  modifications,  and  contended  that  the 
isolation  of  a  few  individuals,  a  condition  which  w^ould  occur  most  frequently 
during  migrations,  was  a  necessary  postulate  in  accounting  for  the  origin  of 
each  new  variety  or  species.  As  will  be  stated  presently,  the  principle  of 
isolation,  slightly  modified,  has  been  applied  by  other  writers.  Bronn,  Nägeli 
and  A.  Braun  raised  the  objection  to  Darwin's  theory  of  natural  selection 
that  many  organs  are  entirely  useless  to  the  individual,  and  therefore  natural 
selection,  which  depends  upon  the  principle  of  utility,  could  neither  have 
produced  such  organs  nor  could  have  modified  them  in  any  way.  Nägeli 
assumed  that,  in  addition  to  natural  selection,  a  certain  resident  tendency 
toward  perfection,  inherent  in  every  individual,  takes  part  in  conditioning 
the  growth  of  morphological  characters.  Every  Variation  brought  about 
by  external  or  internal  agencies  is  at  once  in  the  nature  of  a  differentiation, 
a  Step  forward  in  the  division  of  labour,  and  consequently  an  advancement. 

Weismann  endeavoured  in  a  similar  manner  to  Supplement  Darwin's  theory 
of  selection  by  his  hypothesis  of  the  continuity  of  germ-plasm.  According  to 
Weismann,  germ-matter  is  of  itself  capable  of  producing  all  variations  that 
are  useful  to  an  organism.  Only  that  which  exists  in  the  original  plasm  or  in 
the  sexual  elements  as  embryonic  rudiments  can  be  transmitted  to  off'spring 
and  become  further  acted  upon  and  developed  by  natural  selection,  according 
to  Weismann's  theory.  The  continuity,  that  is  to  say,  the  perpetual  trans- 
mission of  a  portion  of  the  germ-plasm  from  parent  to  ofFspring,  forms  a 
necessary  postulate  to  the  theory  of  descent. 

Weismann  originally  attributed  only  a  subordinate  influence  to  the 
action  of  physical  environment  as  a  cause  of  variations,  and  particularly 
denied  the  inheritance  of  acquired  characters.  But  in  his  later  writings, 
he  is  inclined  to  admit  that  somatic  variations  due  to  environmental  influences 
may  be  transmitted  to  the  ofFspring,  and  endeavours  to  explain  this  with  the 
help  of  his  germ-plasm  hypothesis.  Thus  he  approaches  in  a  way  the  opinion 
of  his  opponents,  the  so-called  Neo-Lamarckian  school  (represented  by  Herbert 


INTEODUCTION  13 

Spencer,  Cope,  Hyatt,  Osborn,  Semper,  Claus,  Roux  and  others),  which  ranges 
itself  more  and  more  on  the  side  of  Lamarckian  ideas,  and  ascribes  to  the  use 
and  disuse  of  Organs,  and  to  external  conditions,  a  very  considerable  influence 
in  effecting  the  transformation  of  organic  forms.  While,  on  the  one  band, 
Semper,  Locard  and  Clessin  undertake  to  prove  the  direct  action  of  environ- 
ment  on  molhisks  in  a  number  of  instances ;  on  the  other  band,  Cope,  Osborn, 
Roux  and  others,  emphasise  the  effect  of  use  and  disuse,  and  abundance  or 
scantiness  of  food-supply.  Adequate  nourishment  and  exercise  increase  the 
development  of  a  given  organ,  while  physical  conditions  determine  its  form. 
Since  like  causes  produce  like  efFects  in  the  animate  as  well  as  in  the  inanimate 
World,  it  is  obvious  that  similar  organs  must  be  developed  in  a  variety  of  plant 
and  animal  forms  wherever  they  are  subjected  to  similar  external  conditions, 
and  especially  to  the  same  physical  agencies.  A  convenient  explanation  is 
thus  found  for  the  phenomena  of  parallelism,  or  "  convergence,"  which  are 
in  nowise  related  to  one  another  by  inheritance.  The  analogous  swimming- 
organs  of  fishes,  ichthyosaurians  and  whales,  or  the  analogous  limb-structure 
in  long-legged  ruminants,  the  horse,  elephant  and  Carnivora,  are  due  to 
adaptation  to  external  conditions  and  to  use ;  the  same  explanation  also 
accounts  for  the  like  form  of  sternum  in  bats,  birds  and  Pteivsauria,  or  for  the 
spindle-shaped  body  characteristic  of  most  rapid-swimming  fishes,  reptiles  and 
aquatic  mammals,  or  for  the  similar  form  of  jaw  possessed  by  marsupials  and 
varlous  Orders  of  Placentalia.  These  are  all  instances  of  parallelism,  in  which 
it  often  happens  that  two  fundamentally  different  forms  acquire  the  same 
outward  shape,  or  become  provided  with  similar  or  analogous  organs.  Kineto- 
genesis,  or  the  process  of  a  gradual  transformation  of  parts,  especially  parts 
belonging  to  the  internal  skeleton,  skull  and  limbs,  is  very  ingeniously 
interpreted  by  Cope  as  having  been  accomplished  in  mammals  through  the 
agency  of  mechanical  conditions,  use  and  food.  The  same  author  has  also 
traced  the  line  of  progressive  modification  in  fossil  genera  as  exemplified  by 
numerous  series  of  intermediate  forms. 

In  sharp  contrast  to  all  these  opinions  is  the  "  mutation  theory  "  of  de 
Vries.  The  latter  attempts  to  show  that  new  species  of  plants  are  formed 
by  what  he  calls  mutations.  It  should  be  noted  that  this  term  is  used  in  a 
different  sense  from  the  same  word  as  mentioned  on  p.  10,  being  equivalent  to 
saUation,  used  previously  for  the  same  thing.  Mutations,  in  de  Vries's  sense, 
are  more  or  less  strongly  marked  deviations  from  the  normal  type,  appearing 
rather  suddenly  ;  and  de  Vries  claims  that  only  these  are  capable  of  being 
bred  true  by  pedigree-culture,  and  that  they  alone  lead  to  the  origin  of  new 
species.  What  he  actually  did  was  to  demonstrate  that  it  is  possible,  by 
pedigree-culture,  to  produce  true  breeding  forms  (species)  out  of  mutations, 
but  he  failed  to  see  that  the  essential  factor  in  this  process  is  not  the  quality 
of  the  material  he  worked  with  {i.e.  the  mutations),  but  that  it  is  the  pedigree- 
culture,  and  that  this  corresponds  to  the  well-known  factors  of  selection  and 
Isolation. 

The  latter  principle,  originally  introduced,  as  has  already  been  stated,  by 
Moritz  Wagner,  has  recently  been  put  forward  by  other  writers  (Baur, 
Ortmann,  Gulick,  etc.)  as  a  factor  which  causes  the  differentiation  of  one 
species  into  several  co-existing  species  ("  process  of  speciation,"  O.  F.  Cook). 
While  it  is  admitted  that  the  Lamarckian  factors  of  Variation  and  inheritance 
and   the   Darwinian   factor    of    natural  selection,  are  real   and  actual,   it  is 


14  ELEMENTS  OF  PALEONTOLOGY 

evident  that  these  are  not  sufficient  for  the  understanding  of  the  whole  of  the 
evolutionary  process.  They  are  capable  of  explaining  the  transformation  of 
one  existing  form  into  one  other  form,  but  fail  to  account  for  the  fact  that 
often  tvvo  or  more  different  forms  have  originated  from  a  single  ancestral  type. 
Isolation,  biological  or  ecological  Separation,  or  habitudinal  segregation,  are 
synonymous  terms  applied  to  a  fourth  factor,  which  is  important  for  render- 
ing  the  process  of  speciation  more  intelligible.  These  terms  signify  that 
the  descendants  of  one  ancestral  form  living  amid  a  definite  set  of  ecological 
(or  environmental)  conditions,  begin  to  adapt  themselves  to  different  sets  of 
conditions,  as  a  result  of  which  they  become  ecologically  separated  or  segregated. 
Each  group  of  descendants  consequently  becomes  subject  to  different  infiuences 
of  environment,  and  in  responding  to  such  develops  along  different  lines,  the 
diverg'ence  becoming  finally  so  great  as  to  be  of  specific  value. 

According  to  the  view  that  has  just  been  stated,  it  is  necessary  to 
recognise  that  the  whole  process  of  evolution  is  a  very  complex  one ;  that  it 
is  the  ultimate  outcome  of  a  number  of  factors,  each  of  which  has  its  own 
special  efficacy,  and  may  be  sometimes  antagonistic  to  the  others ;  and  that  of 
the  various  factors  engaged  the  following  four  are  the  most  potent  and  most 
essential :  Variation,  inheritance,  natural  selection  and  Separation.  This  view  is 
perhaps  to  be  regarded  as  the  most  satisfactory  explanation  of  the  organic 
World  and  its  upbuilding  that  has  yet  been  put  forward.  Nevertheless,  though 
it  cannot  be  gainsaid  that  the  four  operative  principles  just  mentioned  are 
actively  at  work,  it  is  difhcult  sometimes  to  trace'  their  causes.  This  is 
particularly  true  of  those  factors  known  as  Variation  and  inheritance.  As  to 
the  former  of  these  factors,  the  rival  hypotheses  of  the  Lamarck-Darwinian 
and  of  the  Weismannian  school  are  contradictory  with  reference  to  the  cause 
of  inheritable  Variation.  With  regard  to  the  cause  of  inheritance,  important 
discoveries,  such  as  the  Mendelian  law,  have  been  made,  but  these  are  too  far- 
reaching  to  permit  of  a  satisfactory  account  in  limited  space. 

Life-Period  and  Extinction  of  Species. — Observation  shows  that 
different  organisms  are  by  no  means  equally  susceptible  to  Impulses  received 
from  the  outer  world.  Many  fossil  genera  remain  almost  wholly  unchanged 
throughout  a  number  of  formations  (Foraminifera,  Cidaris,  Nautilus,  Lingula, 
Terebratula,  Insectivora),  and  hence  may  be  designated  as  persistent  or  conservative 
types,  in  contradistinction  to  variable  types.  The  latter  pass  through  rapid  changes 
at  the  beginning  of  their  career,  develop  a  great  variety  of  forms,  and  send  out 
branches  and  off-shoots  in  all  directions  up  to  a  certain  point ;  they  may  then  die 
out  af ter  a  comparatively  short  period  of  ascendency  (Nummulites,  Graptolites, 
Cystids,  Blastoids,  Tetracoralla,  Perischoechinoida,  Trilobitae,  Rudistae,  Ichthy  o- 
sauria,  Pterosauria,  Dinosauria,  Amblypoda,  Toxodontia,  etc.),  or  in  some  cases 
may  even  continue  on  to  the  present  day  with  undiminished  vitality  (Spatangidae, 
Clypeastridae,  many  land  and  fresh-water  mollusks,  crabs,  lizards,  snakes, 
ruminants,  apes).  Not  infrequently  types  that  were  originally  variable  pass 
over  gradually  into  persistent ;  their  power  of  adaptation  dwindles,  they  grow 
less  plastic,  become  incapable  of  sending  off  new  varieties,  species  or  genera, 
and  as  the  less  vigorous  of  their  number  become  worsted  one  after  another,  they 
finally  stand  out  as  isolated  relics  of  antiquity  {Isocrinus,  Hatteria,  2'apirus, 
Equus,  etc.)  in  the  midst  of  rehabilitated  surroundings.  A  one-sided  develop- 
ment  in  a  certain  direction,  excessive  size,  abnormal  (hypertrophic)  peculiarities, 
or  too  high  specialisation  of  organs,  is  as  a  rule  injurious  to  the  form  and 


INTRODUCTION  15 

leads  usually  to  its  extermination.  Many  groups  remarkable  for  their 
extreme  differentiation  (Dinosauria,  Pterosauria,  Amblypoda,  Toxodontia, 
etc.)  have  become  extinct  probably  for  this  reason,  since,  having  advanced  so 
far  in  a  single  limited  direction,  adaptation  in  other  directions  was  no  longer 
possible. 

Persistent  types  seldom  produce  a  large  number  of  species  during  a  single 
geological  period ;  types  that  start  up  suddenly  and  proceed  to  vary  rapidly 
as  a  rule  soon  die  out ;  while  groups  that  develop  slowly  and  steadily  usually 
contain  in  their  growth  the  promise  of  great  longevity. 

Some  very  ancient  types  have  persisted  to  the  present  day  in  highly 
saline  lakes,  or  in  salt  paus,  in  acid,  alkaline,  very  cold  or  otherwise  unnatural 
situations.  These  represent  dominant  types  of  past  ages  which,  vigorous  and 
adaptable,  when  forced  by  internal  specific  pressure  due  to  the  enormous 
increase  in  the  numbers  of  individuals  were  able  to  invade  and  adapt  them- 
selves  to  physically  and  chemically  unfavourable  localities.  The  subsequent 
development  of  other  types,  younger  and  more  vigorous,  has  extirpated  them 
from  all  the  more  desirable  situations,  though  these  types  have  not  proved 
sufficiently  adaptable  or  vigorous  entirely  to  exterminate  them. 

The  fauna  of  the  ocean  deeps  and  of  biologically  unfavourable  situations 
generally  is,  therefore,  a  curious  composite  of  the  more  vigorous  and  adapt- 
able types  of  animal  life  from  the  Cambrian  to  the  present  day,  including 
f orms  which  were  dominant  in  all  earlier  epochs,  as  well  as  forms  derived  directly 
from  recent  ancestors. 

For  the  extinction  of  many  plants  (Sigillaria,  Lepidodendron,  Cordaites)  and 
animals  (Blastoids,  Tetracoralla,  Trilobites,  Ammonites,  Rudistae,  Ichthyosaurs, 
etc.)  of  former  periods  no  adequate  explanation  has  as  yet  been  found.  Changes 
in  external  conditions,  especially  such  as  regards  the  distribution  of  land  and 
water,  climatal  conditions,  saltness  of  the  water,  volcanic  eruptions,  paucity  of 
food-supply,  the  encroachments  of  natural  enemies,  and  diseases,  may  have 
led  to  the  extinction  of  certain  forms,  but  such  conjectures  signally  fail  to 
account  for  the  disappearance  of  an  entire  species  or  particular  groups  of 
organisms.  Oftentimes  extinction  seems  to  have  been  caused  merely  by 
superannuation.  Long-lived  forms  belong  for  the  most  part  to  persistent 
types  whose  ränge  of  species  is  limited.  Their  reproductive  functions  have 
declined,  and  like  an  individual  in  its  senescence,  they  evince  the  Symptoms  of 
decrepitude  and  old  age.  Darwin  attributes  the  extinction  of  less  well-adapted 
organisms  to  the  struggle  for  existence  ;  but  since,  according  to  the  theory  of 
natural  selection,  new  species  arise  only  with  extreme  slowness  by  means  of 
the  gradual  accumulation  of  useful  variations,  and  since  in  like  manner  their 
less  successful  competitors  are  only  very  gradually  crowded  out,  we  should 
expect  to  find  in  the  rocks,  supposing  that  the  paleontological  record  were  in 
any  degree  perfect,  all  manner  of  extinct  intermediate  forms,  and  we  should  be 
able,  at  least  for  those  groups  especially  liable  to  conservation,  to  build  up 
complete  ancestral  trees.  But  as  Observation  shows,  not  only  do  most  plants 
and  animals  now  living  in  a  wild  state  adhere  to  their  peculiar  characteristics 
with  great  tenacity,  exhibiting  barely  appreciable  changes  even  in  the  course 
of  hundreds  or  thousands  of  years,  but,  furthermore,  fossil  species  remain 
within  the  limits  of  a  single  geological  period  fairly  constant.  With  the 
beginning  of  a  new  epoch  or  period,  however,  which  is  usually  indicated 
in  the  section  by  lithologic  changes,  a  greater  or  less  number  of  species  either 


16  ELEMENTS  OF  PALEONTOLOGY 

entirely  disappears,  or  is  replaced  by  closely  related,  but  at  the  same  time 
more  or  less  different  forms.  Obviously,  therefore,  there  have  been  periods 
when  the  process  of  transformation  and  the  weeding  out  of  organisms  were 
greatly  accelerated,  and  following  upon  these  reconstructive  periods  long 
intervals  of  repose  have  ensued,  during  which  intervals  species  have  retained 
their  characteristic  forms  with  but  little  Variation.  The  fact  that  evolution 
has  advanced  by  occasional  bounds  or  leaps  Stands,  however,  in  nowise  contra- 
dictory  to  the  theory  of  descent. 

The  whole  animate  Community  at  any  point  on  the  earth's  surface  rests 
normally  in  a  State  of  equilibrium,  the  balance  being  maintained  by  the  com- 
bined  activity  of  all  ranks  and  members  of  society.  For  the  preservation  of 
this  balance  nature  practises  a  most  rigid  domestic  economy.  Every  plant 
depends  upon  particular  conditions  of  soil,  food,  temperature,  moisture  and 
other  requisites  for  its  support ;  and  these  conditions  govern  its  distribution 
and  increase  in  the  last  degree.  Every  plant  controls  the  destiny  of  all 
animals  subsisting  upon  it ;  their  numbers  multiply  with  its  increase,  and 
wane  with  its  decrease.  The  fate  of  these  creatures  determines  that  of  their 
natural  enemies,  who  stand  in  similar  relationships  to  still  remoter  circles ; 
and  hence  no  form  can  overstride  the  bounds  set  for  it  by  the  general  balance 
without  disturbing  the  whole  general  System  of  economy.  Let  the  flora  or  fauna 
of  a  given  region  become  altered  by  the  extinction  of  a  number  of  species,  or 
by  the  introduction  of  new  and  more  powerful  competitors,  the  balance  is 
immediatöly  upset.  In  the  first  instance  vacant  places  must  be  filled  up,  and 
in  the  second,  room  must  be  made  for  the  newcomers  at  the  expense  of  the 
settled  Community.  Thus,  wherever  climatal,  orographic,  or  other  changes 
are  instrumental  in  bringing  about  the  extermination  of  large  numbers  of 
plants  and  animals  during  the  lapse  of  a  geological  period,  a  State  of  inequi- 
librium  must  necessarily  result.  But  thereupon  the  struggle  for  existence 
is  waged  with  unwonted  severity  among  the  survivors,  until  finally  a 
readjustment  is  established,  and  a  pause  in  the  formation  of  new  species  ensues. 

The  whole  course  of  evolution  in  the  organic  world  during  past  geological 
periods  indicates  not  only  definite  progression  in  all  branches  of  the  animal 
and  vegetable  kingdoms  up  to  their  present  State,  but  also  a  more  perfected 
specialisation.  Granting  that  the  theory  of  descent  is  true,  and  that  all 
organisms  have  developed  from  a  single  primitive  cell,  or  from  a  few  primitive 
ground-types,  then  every  new  growth  and  differentiation  must  stand  for  im- 
provement  and  progress,  leading  gradually  to  the  development  of  more  or  less 
highly  specialised  organs,  and  to  a  division  of  labour  in  their  physiological 
functions ;  the  higher  the  degree  in  which  this  is  manifested,  and  the  more 
conformably  to  apparent  purpose  and  utility  that  each  organ  fulfils  its 
functions,  the  more  perfect  is  the  organism,  as  we  conventionally  term  it. 

Evolution  in  the  organic  world  has  not  advanced  in  a  simple,  straightforward 
direction,  but  its  course  has  been  exceedingly  complicated  and  circuitous. 
The  biological  Systems,  accordingly,  do  not  suggest  to  us  the  similitude  of  a 
ladder  with  its  numerous  rounds,  but  rather  that  of  an  enormously  ramifying 
tree,  whose  topmost  twigs  represent  the  youngest,  and,  on  the  whole,  the 
most  perfect  forms  of  every  brauch.  The  root,  trunk,  and  a  goodly  portion 
of  the  Upper  limbs  lie  buried  in  the  earth  ;  and  only  the  ultimate  green 
shoots,  the  last  and  most  highly  difFerentiated  members  of  long  ancestral 
lines,  blossom  forth  in  the  world  of  to-day. 


Phylum  I.    PROTOZOA. 

Protozoa  are  unicellular  organisms  with  bodies  consisting  of  sarcode  (proto- 
plasm),  usually  very  minute,  frequently  microscopic  in  size,  and  without 
difFerentiated  tissues  or  organs,  They  are  water-inhabitants,  take  in  nourish- 
ing  matter  either  at  any  point  on  the  periphery  of  the  body  whatsoever,  or 
through  a  so-called  moiith  (cytostome),  and  reject  the  undigested  portions  either' 
from  any  part  of  the  body  whatsoever,  or  from  a  definite  point  called  the  anal 
aperture  (cijiopijge).  The  contractile  sarcode  almost  invariably  contains  one 
or  more  nuclei,  and  exhibits  considerable  diversity  of  structure  and  difFerentia- 
tion.  Locomotion  is  accomplished  by  means  of  vibratile  cilia,  flagella,  pseudo- 
podia  or  irregulär  processes  of  the  periphery.  Reproduction  takes  place  by 
means  of  budding  or  self-division,  which  latter  process  is  often  preceded  by  a 
temporary  conjugation  of  two  individuals.  Protozoa  are  divided  into  four 
classes,  only  the  first-named  of  which  is  known  to  occur  in  the  fossil  State  : 
Sarcodina,  Flagellata,  Infusoria  and  Gregarina. 

Olassl.    SARCODINA. 

Protozoa  with  or  without  a  test,  having  in  fully  developed  individuals  well 
charaderised  pseudopodia,  either  digitale,  reticulate  or  radiale,  with  or  without  axial 
filaments. 

Subclass  1.     RHIZOPODA. 

Sarcodina  either  naked  or  with  a  definite  test,  the  pseudopodia  either  lohose  or 
reticulate  ;  the  adult  form  is  amoeboid. 

Order  1.     AMOEBIDA. 

The  animals  constituting  this  order  do  not  occur  as  fossils.  There  are 
found,  however,  in  chalk  and  many  marine  limestones  minute  calcareous 
bodies  resembling  coccoliths,  such  as  are  present  in  vast  quantities  in  deep-sea 
ooze  of  existing  oceans.^ 

^  To  the  Amoebida  were  foniierly  assigned  by  Huxley  and  Haeckel  the  so-called  Bathybius,  a 
reticulated  colloidal  snbstance  coniposed  of  anastomosing  Strands,  occuiring  at  great  depths  in  the 
Atlantic  Ocean.  Sir  Wyville  Thomson  and  Moebins  regarded  it  as  aprecipitate  of  calcium  siilphate, 
intermingled  with  decomposed  organic  matter.  In  deep-sea  ooze,  which  consists  chietly  of  linie 
carbouate,  as  well  as  in  Bathybius,  great  quantities  of  minute  calcareous  bodies  of  various  shapes 
are  found,  such  as  also  occur  as  an  essential  constituent  of  chalk,  marls  and  most  marine  lime- 
stones belonging  to  older  geological  periods  (cf.  C.  W.  Gümbel,  Neues  Jahrbuch  für  Mineralogie, 
1870,  p.  7f>3).  Ehrenberg  termed  these  bodies  morpholites,  and  regarded  them  as  inorganic  in 
VOL.  I  17  C 


18  PROTOZOA— RHIZOPODA  phylüm  i 


Order  2.     FORAMINIFBRA  d  Orbigny. 


Bhiso^oda  usuaüy  wUh  a  lest  wJUch  is  typkaüy  cakareous  hut  may  be  säkeous 
or  agghdinaled;  consisting  of  one  ar  mare  Chambers  ;  pseudopodia  räiculaU. 

The  Foraminifera  are  for  the  most  pari  minnte  animals  varring  in  size 
from  a  fraction  of  a  mülimetre  to  several  millimetres  in  length,  but  may 
deTelop  a  t^t  several  inches  across ;  these,  however,  are  rare  exceptions.  A 
few  species  occur  in  fresh  or  brackisli  water,  but  the  great  majoritj  live  in 
the  ocean.  They  are  found  at  all  depths,  but  are  most  frequent  at  moderate 
depths  in  the  ocean  basins,  where  they  form  characteristic  deposits — the 
so-called  "globigerina  ooze."  In  the  vicinity  of  tropical  coral  islands  many 
species  occur  in  great  abundance. 

The  animal  itself  is  a  single-celled  form  with  one  or  many  nuclei,  as  will 
be  later  explained  The  test,  in  many  cases  at  least^  is  really  an  internal 
structure,  as  the  thin  film  of  protoplasm  which  covere  it  in  the  perforate 
forms,  and  probably  in  others,  is  capable  of  secreting  the  material  of  the  test 
to  repair  fractures  and  the  like. 

nature.  Haxley  (Journal  Jücrosoop.  SdaK«,  16&S,  VUI.  2^o.  Cj,  oJmI  Haöck^  ^JcZi^iäeiie  Zeit- 
schrift, 1870^  V.  3,  p.  18)  regarded  thon  st  fiist  as  poitions  of  Baikgtiu*,  and  des%iiated 
them  coecolühs  (Fig.  1).  The  simple^  dialdike  varieties,  eonTex  <m  fhe  uppcr  aide  and  eoneaxie  <m 
the  lower,  were  tenned  dücoUOu  (Flg.  1,  e) ;  whfle  tiiose  ctNuposed  (rf*  tvo  ckisdj  applied  di^ks 
of  diffex^oit  sizes,  resraiblii^  cnff-battons  in  pvofile,  were  refened  to  as  ejfoihoUtks  (Flg.  1,  o,  b). 
Coocolitfas  are  only  risible  ander  poveis  of  800  to  1000  diametezs,  and  exhilxt,  as  a  ruie,  a  namber 
of  »mes  differing  in  thrär  refnctire  indioes,  whidi  are  disposed  aboot  a  än^,  double  <«-  star- 

sha^ed  centnl  grurale.  Fre- 
qaenüy  laige  nnmbos  of  eooeo- 
liths  beoome  a^gregxted  to- 
gether  in  tiie  fonn  of  fireel  j 
sospended  ^icmles  ar  coom- 
9phtres{¥ie.2).  Besides  cocco- 
litlis,  oäier  minnte,  rod-shaped, 
cakareoos  bodiesare  siHnetinies 
Fio.l,a,&.— Cbo(»Itas(qpadlMlifi«)ftomäieAyaatic  met  with,   whidi  are   ebarac- 

£we  and  in  Profile  (^DerHKel^^ ^^^  t«sriüed  by  a  discwdal  or  craci- 

and  in  i^ofile(mftera  Schmidt).  fem  ealaigenicnt  at  «le  aid. 

FiolIT— Oieoospfeef«sframtlieAtlaiitieOeeaa(ailwHaeekeI).  These  are    called    rluMoUiks 

FIO.S.— ffto&doUlftsfromacAdräticSeaCiftieraSehmidtX   AUligiues     (Flg.    3),   and    their    nodular 

magnifiedTOOdiametas.  aggwgations        HuAdmpkerrs. 

WyTille  ThomsoD,  Gart«-  and 
Murray  would  identify  ooooosidierBB  as  unJoeUnlar  aJ^jae,  or  as  spomigia  of  algse,  whfle  iTa^flr«»! 
crestes  for  them  a  special  gronp,  **  Calcoeytae"  and  assjgns  them  provisionally  to  the  Protophytes. 
Acoocding  to  Hartlng,  howevo-,  the  ac^icm  of  anunonia  genetated  by  the  deeomponlion  of  albnmin- 
ons  msttrar  hdd  in  solutiaa  in  lime  saifAuie  or  lime  <^k«de|,  canses  the  s^arstifm  out  ot  minnte 
calcareons  didcs  which  bear  a  striking  reaamhlanee  to  oooocdiths.  Hcaiee  it  would  appear  that 
the  farmaüxm  ol  exxxs^vdj  fine  dirided  paztides  of  lime  in  the  sea  should  take  place  whesrerer 
there  are  decxmiposing  slbamiiHms  or  nitrageooos  sabstaaces  fwesent,  and  ibe  calcium  sol^iate 
held  in  Solution  in  the  water  beomnes  pvedpitated  as  cahänm  csrbonateL 

^  Utoature  :  dPOrbigmjf,  A.,  Foraminißres  fossiles  du  bassin  tertiäre  de  Yienne.  Fluis.  1846. 
— EhrtiAerg,  G.  O.,  Mikrogeokgie,  18S4,  and  AUiaMlungoi  der  Preoss.  Akad.  Wisa.,  1839. — 
SAuUm,  Max,  lieber  den  Oiganianus  der  Pdythalamien.  häpaäg,  1854. — Ctefpes/er,  W.  B., 
Introductran  to  the  Study  of  the  ForaminiCaa.  Bay  Sodety,  1862. — Rems»,  E.  A.,  STumerons 
Reports  in  Stzungsberichte  da*  Wveota  Akadonie,  from  1860  «mwazds. — Sdkwager,  Comrad, 
Sbggio  di  nna  dasäficaäcme  dei  F<waminiferL  Sollet.  Condtato  GeoL,  1876l — Bmdy,  W.  B., 
MfmograjA  of  Guboniferons  and  Pernüan  F<»aniinifenL  PSiaetmtagrsph.  Soc,  1S76. — Bradp, 
W.  B.,  Beport  on  the  Foruninifera^  Scümt.  Besults  C3ia]lengia-  Exped..  Zodogy,  XL,  1884. — 
Skerbom^  C  D.,  Index  to  the  Gkmera  and  Spedes  of  the  Fnsmini&n.  &^th.  Mise  ColL. 
1895,  T<d.  xxzriL — Egger,  J.  GL,  Fonminiftrraii  dar  Seeweaer  Kreädesehichteai.  Sitiber.  Bayer. 
Akad.  Wlss.,  1909,  No.  W.—SAeOwiem^  E.,  Monographie  der  Fnsulinen.  Fslaeontogr.  1908-1912, 
Tols.  It.,  Ux. 


ORDER  TT  FORAMINIFERA  19 

Comparatively  little  is  known  concerning  the  animal  of  the  Foraminifera 
except  in  certain  littoral  species.  As  single-celled  animals  the  Foraminifera 
are  especially  interesting,  and  their  structures  do  not  need  explanation  on  the 
basis  of  Organs  or  tissnes.  There  is  much  beauty  in  the  ciirves  of  the  test 
and  in  its  ornamentation,  the  patterns  of  the  latter  being  often  very  intricate. 

Throughout  the  group  of  Foraminifera  there  is-  a  nearly  complete  series, 
from  a  simple  gelatinous  covering  of  the  cell  in  some  of  the  fresh-water  forms 
to  the  complex  calcareous  test  of  the  higher  groups.  The  fresh-water  forms, 
while  not  considered  in  the  systematic  part  of  this  treatise,  are  nevertheless  of 
especial  interest  on  account  of  their  primitive  characters.  In  Myxotheca  the 
simplest  sort  of  covering  is  found,  a  gelatinous  test  which  is  flexible,  so  that 
it  takes  the  shape  of  the  changing  form  of  the  cell.  There  is  here  also  no 
definite  aperture,  the  pseudopodia  being  pushed  through  at  any  point.  In 
others  of  the  fresh-water  forms  the  test  may  be  of  flexible  chitinous  material, 
biit  has  a  definite  shape  when  the  animal  is  at  rest  and  usually  one  or  more 
definite  and  permanent  orifices. 

In  the  marine  species,  which  form  the  basis  of  the  present  work,  there  is 
iisiially  a  definite,  specific  form  to  the  test,  and  the  aperture  is  permanent. 
The  materials  used  in  making  the  test  may  be  grouped  in  two  classes  :  (1) 
those  derived  from  foreign  sources,  and  (2)  those  secreted  by  the  animal  itself. 
The  foreign  materials  are  derived  from  the  bottom  on  which  the  animal  lives, 
and  therefore  even  in  the  same  species  found  under  difFerent  conditions  there 
is  some  Variation  in  the  character  of  the  materials  used.  In  general,  however, 
there  seems  to  be  a  certain  amount  of  selective  power  on  the  part  of  certain 
forms,  and  such  characters  have  been  used  as  of  generic  rank  in  systematic 
work.  The  foreign  material  most  frequently  used  is  the  mud  or  sand  of  the 
ocean  bottom,  but  certain  forms  use  sponge  spicules,  either  making  them  into 
a  soft  f elted  mass  (Pilulina)  or  arranging  them  in  a  definite  manner  and  firmly 
cemented  {Technitella).  Other  foraminiferal  tests  may  be  used,  as  may  various 
small  bodies  which  come  within  the  ränge  of  the  animals.  The  cement  in  the 
agglutinated  tests  may  be  chitinous,  of  iron  oxide,  or  calcareous. 

Of  these  calcareous  tests  two  sorts  have  been  recognised,  one  with  a  definite 
aperture  or  series  of  apertures  and  with  minute  pores  (the  perforate  group), 
the  other  with  a  definite  aperture  or  series  of  apertures  but  without  minute 
pores  (the  porcellanous  group).  By  many  writers  the  latter  group,  represented 
by  the  Miliolidae,  has  been  held  to  be  primitive  and  a  group  which  had  not 
developed  perforations.  On  the  other  hand,  certain  evidence,  such  as  the 
perforate  condition  of  the  early  chamber  of  Peneroplis  and  other  genera,  would 
indicate  that  they  are  derived  from  the  perforate  group,  and  that  the  lack  of 
pores  instead  of  being  a  primitive  condition  may  in  reality  be  a  specialised 
one  derived  from  a  condition  in  which  pores  were  developed  throughout  the 
life  of  the  individual. 

In  general  the  test  of  the  Foraminifera  may  be  single-chambered  or  many- 
chambered.  Contrary  to  the  impression  given  by  certain  works  on  the  group, 
the  process  of  adding  Chambers  in  the  Foraminifera,  while  superficially  like 
budding  or  gemmation,  is  not  necessarily  or  usually  accompanied  by  nuclear 
divisions.  That  is,  instead  of  the  new  Chambers  being  potential  individuals 
they  are  simply  integral  parts  of  one  cell,  and  in  the  uninucleate  form  the 
>ingle  nucleus  is  found  in  about  numerically  the  middle  chamber.  In  the 
process  of  adding  a  new  chamber  a  portion  of  the  protoplasm  is  protruded 


20  PROTOZOA— RHIZOPODA  phylum  i 

from  the  aperture  and  a  new  Chamber  wall  then  formed  about  it.  In  some 
cases  a  complete  wall  is  formed  with  each  newly  added  Chamber,  but  in  others 
the  adjacent  parts  of  previous  Chambers  form  the  inner  walls  of  the  new^ 
Chamber,  and  new  walls  are  formed  only  on  the  free  i)arts  of  the  protoplasmic 
mass.  In  the  open  tubulär  test,  such  as  Astrorhiza  or  Hyperammina,  increase 
in  the  protoplasmic  body  is  accompanied  by  addition  of  material  at  the  open 
end  of  the  tube  and  an  increase  in  size  results.  In  single-chambered  types, 
such  as  Lagena,  the  manner  of  increase  in  size  is  problematical,  if  there  be  any 
at  all.  In  such  forms  the  entire  test  may  be  made  in  its  completed  form  at 
once  after  division,  as  is  the  case  in  certain  of  the  fresh-water  Rhizopods. 

In  the  tests  having  more  than  a  single  Chamber  the  apertures  of  the  first- 
formed  Chambers  become  internal  as  a  rule,  and  a  complexity  of  relations  to 
the  outside  medium  is  thus  brought  about.  One  of  the  simplest  arrangements 
of  the  Chambers  is  a  linear  series.  Such  an  arrangement  is  seen  in  Ileophax 
and  Hormosina.  Another  very  common  plan  of  arrangement  is  a  planospiral, 
as  in  Ammodiscus.  This  may  be  varied  by  having  the  revolving  line  in  a  spire 
and  then  the  whole  test  becomes  trochoid,  as  in  Trochammina.  Another 
common  arrangement  is  a  biserial  one,  the  Chambers  being  on  opposite  sides 
of  the  axis,  as  in  Textularia.  These  four  plans  or  some  modification  of  them 
are  the  characteristic  arrangements  for  the  Chambers  in  most  of  the  secreted 
tests.  Oftentimes  more  than  one  plan  of  arrangement  enters  into  the  forma- 
tion  of  the  test.  Dimorphism  was  used  for  this,  but  that  term  has  been  used 
elsewhere  with  a  very  different  meaning.  As  here  viewed,  this  life-history 
with  several  distinct  methods  of  growth  has  a  deeper  significance  than  has 
usually  been  attached  to  it.  It  seems  to  have  a  definite  phylogenetic  bearing 
in  each  particalar  group.  The  term  "  dimorphism  "  would  hardly  cover  the 
case  in  some  genera,  where  eight  or  more  distinct  stages  may  be  made  out, 
each  with  its  characteristic  form  of  Chamber,  yet  all  appearing  successively  in 
a  Single  test. 

The  number  of  Chambers  in  the  complex  tests  varies  from  a  few  to  a  great 
many.  Where  the  size  of  the  test  becomes  considerable  and  the  Chambers 
correspondingly  large,  the  Chamber  is  often  divided  up  in  various  ways  into 
chamberlets,  as  in  Orbitolites.  In  such  cases  the  adjoining  chamberlets  are 
usually  in  free  communication  with  one  another.  The  walls  of  the  chamber- 
lets give  additional  strength  in  many  forms  in  which  they  are  developed. 
Another  characteristic  modification  in  some  genera  is  the  development  of 
labyrinthic  structures  in  the  interior  of  the  Chambers.  Such  structures  are 
seen  in  Oyclammina,  Haplostiche,  Fabularia,  etc.  In  general,  it  seems  tq  be  a 
mark  of  the  culmination  of  certain  lines  in  development,  and  many  of  the 
genera  which  developed  such  labyrinthic  structures  are  now  extinct.  From 
the  appearance  of  a  series  of  such  tests  of  one  species  at  different  stages  in 
development,  it  would  seem  as  though  this  labyrinthic  condition  was  developed 
as  a  secondary  growth  in  the  Chamber.  One  of  its  uses  may  be  to  give  added 
strength  to  the  test,  but  this  does  not  always  seem  to  be  the  case,  for  it  may 
occur  in  tests  which  are  characterised  by  thick  walls. 

The  aperture  in  a  given  species  seems  to  be  rather  constant  when  the 
development  is  understood.  Much  has  been  written  upon  this  subject ; 
apertural  characters  have  been  used  by  some  authors  as  a  basis  for  systematic 
work,  and  discarded  by  others  as  very  variable.  In  a  few  specimens  it  may 
seem  at  first  sight  as  though  the  apertural  characters  were  very  variable,  but 


ORDER  II  FORAMINIFERA  21 

with  a  large  series  showing  different  stages  in  development  another  phase  of 
the  matter  is  presented.  In  certain  cases  there  is  a  very  decided  change 
in  the  condition  of  the  aperture,  but  these  changes  appear  at  different  stages 
in  the  life-history,  and  all  may  be  seen  by  cutting  back  a  single  full-grown 
individual.  In  general,  it  has  seemed  from  recent  studies  that  apertural 
characters,  when  studied  in  large  series,  are  a  rather  dependable  set  for 
systematic  work,  and  this  is  true  in  the  Miliolidae  and  Lagenidae  especially. 

In  many  species  teeth  of  various  sorts  are  developed  in  the  aperture,  and 
these  teeth  are  subject  to  various  modifications.  It  can  be  demonstrated 
that  these  modifications  occur  in  a  definite  sequence,  and  that  this  sequence  is 
important  from  a  phylogenetic  point  of  view. 

In  a  considerable  number  of  genera  a  definite  tubulär  neck  is  developed, 
with  the  aperture  at  its  end.  This  neck  is  seen  in  many  genera  in  a  great 
many  modifications,  and  in  Lagena  the  tube  may  be  inverted  and  be  directed 
into  the  chamber  of  the  test. 

It  is  obvious  that  a  very  long  slit-like  aperture  may  be  a  source  of  weak- 
ness  to  the  test,  especially  when  it  is  at  the  edge  of  a  thin  chamber.  Usually 
in  such  cases,  as  in  Orhitolites,  the  animal  changes  its  aperture  from  a  single 
one  in  each  chamber  to  a  considerable  number.  This  is  often  coincident  with 
the  development  of  chamberlets,  but  not  invariably  so,  for  multiple  apertures 
occur  in  PeneropUs  where  there  are  no  chamberlets. 

Many  of  the  tests  of  the  Foraminifera  are  beautifully  ornamented.  Eaised 
costae,  striations,  knobs,  spines  and  punctate  areas  form  the  main  types  of  orna- 
mentation.  Several  of  these  or  combinations  of  them  may  occur  in  a  single 
species,  the  form  of  the  ornamentation  often  changing  as  the  Chambers  of  the 
test  are  developed.  Certain  of  the  simpler  forms  of  ornamentation  may  occur 
as  parallelisms  in  widely  separated  groups.  As  a  rule,  the  proloculum'and 
early  Chambers  are  smooth  and  unornamented,  but  there  are  certain  exceptions, 
as  in  Nodosaria,  for  example,  where  in  some  species  ornamentation  may  occur 
on  the  first  chamber.  In  specialised  genera  it  is  not  uncommon  to  find  certain 
of  the  species  with  the  early  portion  of  the  test  ornamented,  but  the  last- 
formed  Chambers  with  a  loss  of  ornamentation  and  a  consequent  development 
of  smooth  Chambers.  On  the  other  band,  there  may  be  a  thickening  of  the 
test  from  without  and  the  covering  of  the  Chambers  already  formed  with  a 
secondary  growth,  often  spinöse.  Such  a  condition  is  seen  in  some  species  of 
Bulimina. 

Ordinarily  the  different  parts  of  the  test  are  connected  with  one  another 
by  the  previous  apertures,  but  in  some  cases,  notably  in  Polystomella,  there  is 
a  secondary  canal  System  which  is  very  complex  and  runs  to  all  the  parts. 
This  has  been  worked  out  by  Carpenter  and  others  in  detail. 

For  many  of  the  Foraminifera  two  distinct  phases  have  been  discovered. 
One  of  these,  the  microspheric  form,  has  a  proloculum  or  first  chamber  of 
much  smaller  size  than  the  other — the  megalospheric  form.  These  two  forms 
are  to  be  looked  for  in  all  species. 

The  microspheric  form  (Fig.  4,  B)  has  a  number  of  nuclei,  often  a  larger 
number  than  there  are  Chambers,  scattered  irregularly  through  the  protoplasm 
of  the  body.  There  seems  to  be  a  rather  definite  relation  between  the  size  of 
the  nuclei  and  the  size  of  the  chamber  in  which  they  occur,  the  larger  nuclei 
being  in  the  larger  Chambers  and  the  reverse.  Apparently  these  nuclei  simply 
divide  in  their  reproduction  during  the  growth  of  the  test. 


22 


PROTOZOA— RHIZOPODA 


rilYLUM  I 


When  the  animal  attains  its  adult  stage  tbere  is  a  great  increase  in  the 
number  of  pseudopodia,  and  the  entire  protoplasm  either  leaves  the  test  and 

accumulates  aboiit  the  exterior  or  is 
drawn  into  the  outer  Chambers. 
Finally,  each  nucleus  gathers  a  mass 
of  protoplasm  about  itself  and  secretes 
the  proloculum  of  a  new  test.  This 
newly  formed  proloculum  is  of  the 
larger  type  and  is  the  first  Chamber 
of  the  megalospheric  form,  instead  of 
being  of  the  same  size  as  that  of  the 
raicrospheric  parent  from  which  it  was 
derived.  The  megalospheric  form  (Fig. 
4,  A)  differs  from  the  microspheric  form 
This  does  not  divide,   but  moves  along  as  new 


Fig.  4. 

Biloculinabradyl  Schlumb.  Receiit ;  Bay  ofBiscay. 
A,  Small  formwith  megasphere.  B,  Large  form  with 
microsphere.     is/^  (after  Schlumberger). 


in  having  a  single  nucleus. 
Chambers  are  added, 
keeping  in  about  the 
middle  Chamber  nu- 
merically.  Nucleoli 
appear  in  increasing 
numbers  as  the  growth 
continues,  and  finally 
the  whole  nucleus 
breaks  down  and  a  great 
number  of  minutenuclei 
appear.  These  draw 
aboüt  themselves  por- 
tions  of  the  protoplas- 
mic  mass  and  then  di- 
vide by  mitotic  division. 
Finally,  the  mass  leaves 
the  test  in  the  form  of 
zoospores.  These  are 
then  supposed  to  con- 
jugate  and  to  give  rise 
to  the  small  proloculum 
of  the  microspheric 
form,  thus  completing 
the  life  cycle,  although 
the  actual  process  of 
conjugation  has  not  de- 
finitelybeen  observed  in 
this  group.  The  empty 
tests  left  behirid  must 
form  a  large  propor- 
tion  of  the  dredged 
Foraminifera.  The 
two  forms  may  be  dis- 
tinguished  by  the  size 
of  the  proloculum  and,  when  sufficiently  known,  by  other  characters  as  well 


Fig.  5. 

Deep-sea  ooze  iiiagiiified  700  diameters.  a,  Bathyhius  with  Coccolitlis  : 
1>,  Individual  Discoliths  and  Cyatholiths ;  c,  Coccospheres  ;  d,  Globigerina ; 
r,  Glohifierina  with  bursted  test ;  /,  Texfularia  ;  g,  g',  Radiolaria ;  h,  i, 
Diatoms  ;  Ic,  l,  Sponge  spicules  ;  m,  Mineral  fragment. 


ORDER  II 


FORAMINIFERA 


23 


The  microspheric  form  is  thus  the  result  of  a  conjugation  or  sexual  process, 
while  the  megalospheric  form  is  the  result  of  simple  division  or  an  asexual 
process.  As  a  rule  the  megalospheric  form  is  by  far  the  most  common,  and 
in  many  species  the  microspheric  form  is  very  rare,  or  even  as  yet  unknown. 
The  microspheric  form,  while  it  Starts  as  a  smaller  individual,  in  most  cases 
attains  a  much  larger  size  than  the  megalospheric,  as  might  be  suspected  from 
the  nature  of  the  reproductive  processes  by  which  it  is  formed.  In  species 
where  there  are  definite  stages  in  development  it  is  usually  the  microspheric 
form  which  repeats  these  most  fully,  these  stages  being  reduced  or  entirely 
skipped  in  the  megalospheric  form  of  the  species. 

In  some  cases  the  megalospheric  form  may  give  rise  to  a  group  of  megalo- 
spheric young  instead  of  to  zoospores.  On  the  whole,  the  life  cycle  agrees  well 
with  the  alternation  of  generations  as  seen  in  certain  other  groups  of  animals. 


Fio.  6. 

Specimen  of  prepared  White  Clialk  from  Meudon,  as  seen  in 
transmitted  light  imder  power  of  300  diameters,  showing  Texhi- 
laria,  Globigerina,  and  Rotalia. 


Fio.  7. 

Thin  slice  of  Plänerkalk  from  Bohemia, 
viewed  in  transmitted  light  under  power  of 
50  diameters,  showing  sections  of  Nodosaria, 
Rotalia,  Frondicularia,  and  numerous  iso- 
lated  Globigerina  Chambers. 


The  vast  majority  of  Foraminifera  are  marine  in  habit.  They  occur  in 
shallow  water  bordering  the  coasts,  sometimes  attached  to  algae,  sometimes 
creeping  on  the  bottom.  A  few  genera  are  extraordinarily  abundant  in  the 
open  sea,  being  found  at  difFerent  depths  as  free-swimming  forms,  and  also  on 
the  floor  of  the  ocean.  Enormous  quantities  of  their  remains  are  spread  over 
vast  tracts  of  the  sea-bottom,  and  down  to  a  depth  of  2300  fathoms  they 
remain  an  essential  constituent  of  the  deep-sea  ooze.  This  is  a  finely  divided 
agglomeration  of  decomposed  calcareous  substances,  such  as  the  shells  of 
mollusks,  corals,  bryozoans,  coccoliths,  radiolarians,  diatoms,  sponges  and 
Foraminifera.  Of  the  latter,  certain  genera  are  remarkable  for  their  extra- 
ordinary  abundance  (Globigerina,  Orbulina,  Pulvinulina,  Biloculina)  (Fig.  5). 

In  the  Atlantic  and  Pacific  Oceans  Globigerina  ooze  is  the  prevailing  deep- 
sea  deposit;  in  the  North  Sea,  along  the  coast  of  Norway,  Biloculina  ooze. 
Numerous    limestones   and   marls   of    older   geological   periods   exhibit   great 


24  PROTOZOA— EHIZOPODA  phylüm  i 

similarity  in  structure  and  chemical  composition  to  the  now  forming  deep-sea 
oozes.  White  Chalk  (Fig.  6)  is  clearly  a  variety  of  abyssal  ooze,  from  which 
siliceous  constituents  have  become  segregated  out,  and  in  which  Textularia 
predominate  instead  of  Glohigerina.  Certain  of  the  Eocene  limestones  of  the 
Paris  basin  are  composed  almost  exclusively  of  the  tests  of  Müiolidae,  while 
others  are  made  up  of  Älveolinae  and  Nummulites.  During  the  Carboniferous 
period  the  chief  role  as  rock-building  organisms  was  played  by  Fusulina. 
Many  dense,  apparently  homogeneous,  or  even  semi-crystalline  limestones  of 
various  ages,  when  examined  microscopically  in  thin  sections,  are  seen  to  be 
composed  in  large  part  of  Foraminifera  and  other  organic  bodies  (Fig.  7). 

Fossil  Foraminifera  are  best  preserved,  being  usually  detachable  from  the 
matrix,  and  at  the  same  time  occur  most  abundantly,  in  unconsolidated  marls 
and  clays  which  are  interbedded  with  calcareous  strata,  or  in  limestones  of  a 
chalky  or  earthy  character. 

The  tests  of  Foraminifera  were  first  discovered  by  Janus  Plancus,  in  1730, 
on  the  beach  of  Rimini,  and  in  the  following  year  they  were  found  by  Beccari 
in  the  Pliocene  of  Bologna.  They  were  long  considered  to  be  shells  of 
mollusks,  and  were  described  by  Breyn,  Soldani,  Fichtel,  d'Orbigny  and 
others  as  Cephalopoda  foraminifera,  in  distinction  from  Cephalopoda  sipfionifera. 
Dujardin,  in  1835,  was  the  first  to  recognise  their  true  character  as  belonging 
to  the  Rhizopoda. 

Family  1.     Gromidae. 

Test  chitinous  with  an  aperture  at  one  or  both  ends  for  the  pseudopodia. 

The  animals  belonging  to  this  family  are  mostly  fresh-water  species  and 
their  occurrence  as  fossils  is  unknown. 

Family  2.     Astrorhizidae  Brady. 

Test  composed  of  agglutinated  material  for  the  most  part,  occasionally  with  a 
chitinous  inner  layer,  consisting  of  a  Chamber  with  several  openings  or  a  tubulär 
test  open  at  both  ends;  or  in  certain  forms  of  a  closed  Chamber  with  a  single 
aperture.     Throughout  the  family  the  test  is  not  divided  into  a  series  of  Chambers. 

Becent  and  very  abiindant  at  depth.  Fossil  in  Paleozoic  and  later 
formations. 

Subfamily  A.     Astrorhizinae  Brady. 

Test  consisting  usually  of  a  tube  open  at  both  ends  or  with  several  tubes  entering 
a  central  Chamber  ;  in  some  species  with  the  tube  branching. 

The  genera  Astrorhiza,  Bhabdammina,  Marsipella,  Bathysiphon  and 
Rhizammina  make  up  this  subfamily.  Apparently  fossil  since  the  Upper 
Jurassic  and  common  in  Recent. 

Subfamily  B.      Saccammininae   Brady. 

Test  consisting  of  a  single  Chamber,  or  group  of  superficially  attached  Chambers. 
The  walls  made  up  for  the  most  part  of  agglutinated  material ;  apertures  sometirnes 
numerous  but  usually  single  ;  tests  free  or  attached. 


K 

HÄRDER  II  FORAMINIFERA  25 

^^H  Saccammina  Sars.  (Fig.  8).  Shell  thick,  with  labyriiithiform  interior ; 
^^■pherical,  pear-shaped  or  fusiform,  with  tubulär  prolongations  at  one  or  both 
^^pnds  ;  sometimes  united  together  in  chains.     Ordovician  (Ayrshire),  Devonian 

(Canada),   Carboriiferous  and  Recent.      Entire  strata  of  Carboniferous  rock 

near  Elfhills,  Northumberland,  are  built  up  by  aS".  carteri  Brady. 

Large-sized  species  of  Astrorhiza,  Fsammosphaera,  Saccariimina,  Hyperammina, 

and  Rhabdammina  are  described  by  Häusler  from  the  Upper  Jurassic  (Trans- 

versarius  beds)  of  Switzerland. 

Thurammina   Brady.      Test   free,   monothalamous,  irregularly  spheroidal, 

usually  with  excrescences  or  spiny  processes.     Upper  Jurassic  and  Recent. 

Siibfamily  C.     Hyperammininae. 

Test  consisting  of  a  globular  proloculum  and  a  more  or  less  elongated,  some- 
times hranching  portion,  but  not  divided  iiito  Chambers;  free  or  attached  wall 
of  various  agglutinated  materials. 

The  genera  Hyperammina,  Saccorhim,  Tolypammina,  Ammolagena,  Jaculella 
and  Sagenina  make  up  this  subfamily.     Some  of  these  occur  as  fossils. 

Subfamily  D.      Ammodiscinae  Ciishman. 

Test  composed  of  a  globular  proloculum  and  long  undivided  tube,  closely  coiled, 
either  planospirally-  or  in  changing  planes  or  to  form  a  spiral  lest ;  wall  of  fine 
sand  with  much  cement. 

Ammodiscus  Reuss.  Test  free,  composed  of  a  proloculum  and  long 
coiled  tubulär  chamber.     Carboniferous  to  Recent. 

Family  3.     Lituolidae  Brady. 

Test  composed  of  agglutinated  material  foi'  the  most  part ;  consisting  of  two  or 
more  Chambers ;  arranged  in  a  linear,  coiled  or  irregulär  series  ;  apertures  usually 
one  to  each  chamber,  but  sometimes  more. 

The  tests  included  in  this  family  all  have  the  wall  composed  of  ag- 
glutinated material  with  a  varying  amount  of  cement  in  the  different  genera. 
Throughout  the  family  as  here  used  the  tests  are  composed  of  two  or  more 
Chambers  and  a  definite  proloculum  is  apparent.  Usually  the  tests  are 
composed  of  a  series  of  Chambers. 

Subfamily  A.     Aschemonellinae  Cushmaii. 

Test  composed  of  agglutinated  material,  divided  irregularly  into  Chambers  mthout 
a  defiyiite  ptlan  of  arrangement. 

Subfamily  B.     ReophäCinae  Cushmaii. 

Test  of  agglutinated  material,  sand  grains,  sponge  spicides,  etc.,  with  a  varying 
amount  of  cement,  Chambers  in  a  linear  series,  aperture  single  at  the  distal  end  of 
the  last-formed  chamber. 

Reophax  Montfort.     Test  free,  composed   of  a  lineal  series  of  Chambers, 


26 


PROTOZOA— EHIZOPODA 


PHYLUM  I 


joined  end  to  end  in  iiearly  a  straight  line,  curved  but  not  coiled,  wall 
coarsely  arenaceous,  Chambers  undivided,  aperture  simple  and  terminal. 
Carboniferous  to  Recent. 

Haplostiche  Reuss  (Fig.  9).  Test  similar  to  Beophax  but  the  Chambers 
divided  into  labyrinthic  cavities,  aperture  in  adult  made  up  of  several  pores 
or  dendritic.     Jurassic  to  Recent. 


Subfamily  C.     Trochammininae  Brady. 

Test  composed  of  several  Chambers,  either  in  a  planospiral  coli,  trochoid  or  other- 
wise  arranged ;  wall  composed  of  sand  grains  of  varying  degrees  of  coarseness 
cemented  with  a  calcareous  or  ferruginous  cement ;  free  or  attached. 

Trochamminoides  Cushm.  (Trochammina  Reuss,  pars)  (Fig.  10).  Test  free, 
composed  of  several  coils,  each  constricted  into  a  number  of  Chamber -like 
portions  with  large  openings  between ;  wall  of  fine  sand  and  yellowish-brown 


A,  Saccammina  carteri 
Brady.  Carboniferous  Lime- 
stone ;  Elf  hüls,  Northum- 
berlaiid.  1/2.  B,  Fractured 
test,  filled  with  interior  cal- 
cite.     10/j  (after  Brady). 


Haplostiche 
horrida  Schwa- 
ger.  Upper 
Jurassic  (Im- 
pressa  clay)  ; 
Gruibingen, 
Württemberg. 


Fig.  10. 


Trochammina  pro- 
tcws  Karrer.  Vienna 
sandston  e  (Senonian) ; 
Hütteldorf,  near 
Vienna. 


Fig.  ]]. 


Lituola  (Haplo- 
phragmium)  irregu- 
laris  Roemer.  Sca- 
phiten  -  Pläner  ; 
Kröndorf,  Boheniia. 


Fig.  12. 

Placopsiliria 
r od  rata  Quenst. 
sp.  Upper  Jur- 
assic (Inipressa 
clay) ;  Reichen- 
bach, Württem- 
berg. 


cement,  aperture  simple  at  the  end  of  the  last-formed  Chamber.  Lias  to 
Recent. 

Ammobaculites  Cushm.  {Haplophragmium  Reuss,  pars)  (Fig.  11).  Test  free, 
chambered,  early  portion  close-coiled  in  one  plane,  later  portion  uncoiled  and 
made  up  of  a  more  or  less  linear  series  of  Chambers  ;  wall  coarsely  arenaceous, 
fairly  thick  ;  aperture  single,  at  the  centre  of  the  terminal  face  of  the  uncoiled 
portion,  but  in  the  coiled  portion  at  the  base  of  the  apertural  face..  Carboni- 
ferous to  Recent,  particularly  abundant  in  the  Jurassic  and  Cretaceous. 

Placopsilina  d'Orb.  (Fig.  12).  Test  rugose,  arenaceous,  attached,  and 
divided  into  pyriform  or  spherical  Chambers,  which  are  joined  in  chains  or  are 
irregularly  united.     Lias  to  Recent. 


Subfamily  D.      Neüsininae   Cuslimaii. 

Test  arenaceous  with  som,e  chitin,  broad  and  flattened,  of  many  Chambers,  early 
portion  coiled,  later  Chambers  broad  and  spreading  ;  sides  with  elbngated  chitinous 
ßaments. 


Here  is  placed  the  single  recent  genus  Neusina  Goes. 


Fig.  13. 
Orhitolina  concava  Lam. 


ORDER  II  FORAMINIFERA  27 

Subfaniily  E.      Orbitolininae. 

Test  siliceoiis,  imperforafe,  crateriform  and.  composed  of  concentric  annuli  which 
iire  partitioned  off  into  numerous  Chambers. 

Orhitolina  Lam.  (Fig.  13).  Test  composed  of  agglu- 
tinated  sandy  particles ;  bowl  -  shaped  to  depressed 
conical ;  upper  surface  convex,  lower  slightly  concave ; 
externally  smooth  or  with  concentric  bands.  Test 
composed  of  multilocular  rings,  the  Chambers  com- 
municating  with  one  another  on  all  sides  by  pores. 
The  outer  portion  of  each  Chamber  is  subdivided  by 
two    secondary    partitions    disposed   at  rieht  anerles   to    cenomanian;    Urscheiau, 

,         .,  -XT  1  i.'ii         T  1     TT  Bavarian  Alps,    a,  Inferior 

each  other.      Very  abundant  in   the   Lower   and    Upper    surface;  b,  superior  sur- 
Cretaceous.     0.  lenticularis  and  0.  concava  Lam.  (eniaIrg'edV'''''''  '''*'''" 

Family  4.     Textulariidae  Schnitze, 

Test  either  arenaceous  or  calcareous,  perforate,  the  Chambers  usually  nnmerous, 
essentially  biserial  or  triserial,  or  in  some  genera  spirally  arroMged. 

The  family  Textulariidae  is  apparently  the  most  primitive,  after  the 
Lituolidae.  A  number  of  the  genera  are  wholly  or  in  part  composed  of 
species  with  arenaceous  tests,  which  is  in  itself  a  primitive  character  in  the 
group.  In  many  species  both  the  microspheric  and  megalospheric  forms 
are  known.  In  the  microspheric  form,  which  repeats  most  completely  the 
phylogenetic  characters,  a  coiled  early  development  succeeding  the  proloculum 
is  commonly  found.  This  stage  may  be  compared  to  the  entire  development 
of  such  a  genus  as  Haplophragmoides  in  the  Lituolidae. 

Subfamily  A.      Spiroplectinae  Cushman. 

Test  either  coarsely  arenaceous  or  calcareous,  or  even  hyaline,  the  early  Chambers 
following  the  proloculum  closely  coiled,  the  later  Chambers  biserial,  occasionally  tending 
to  become  uniserial  in  the  last  developed  Chambers. 

This  subfamily  includes  the  single  genus  Spiroplecta  Ehrb.,  which  in  its 
developmental  stages  connects  the  Textulariidae  with  the  Lituolidae.  Its  de- 
velopment is  primitive  in  that  the  stages  are  seen  in  both  the  microspheric 
and  megalospheric  forms  of  the  species,  and  are  of  comparatively  long  duration. 
Cretaceous  and  post-Tertiary. 

Subfamily  B.     Textülarinae  Brady. 

Test  typically  biserial,  early  portion  in  microspheric  form  offen  with  a  few  coiled 
Chambers,  followed  by  biserial  ones,  later  Chambers  variously  modified  in  diff'erent 
genera,  uniserial,  broadly  extended,  etc.  Wall  either  arenaceous  or  calcareous  and 
hyaline,  perforate ;  aperture  single,  or  in  a  few  cases,  many  present  in  a  single 
Chamber. 

Textidaria  Defr.  (Fig.  14,  A).  Test  usually  elongated,  straight,  tapering, 
or  turbinated.     Chambers  biserial,  altcrnating  and  communicating  with  each 


28 


PßOTOZOA— KHIZOPODA 


PHYLUM  I 


other  by  means  of  slit-like  apertures.      Carboniferous  to  Recent.     Extremely 
abundant  in  the  White  Chalk. 


Fig.  14. 

A,  Tbxtularia  globifera  Reuss.  Upper  Cretaceous  (Senonian) ;  Pattenauer  Stollen,  near  Traunstein,  Bavaria. 
B,  Bolivina  incrassata  Reuss.  Upper  Cretaceous  ;  Götzreuther  Graben,  near  Siegsdorf,  Bavaria.  C,  Flecanium 
gihhosum  d'Orb.  Pliocene ;  Sienna,  Italy,  D,  Grammostomum  {VidvuUna)  gramen  d'Orb.  Recent;  Cuba.  E, 
Gaudryina  rugosa  d'Orb.  Upper  Cretaceous.  Götzreuther  Graben,  near  Siegsdorf.  F,  ClavuUna  communis 
d'Orb.     Miocene  ;  Baden,  near  Vienna. 

Bolivina  d'Orb.  (Fig.  14,  B).     Test  biserial  throughout,  aperture  elongate, 


Fig.  15. 
^.r;t'  tf^mT  ^'''X'^"'"'  'i'O^.b-      Miocene  (Leitbakalk)  ;  Nussdorf,  near  Vienna.    B,  Bulimina  pupoicks  d'Orb. 
Snal  section    iwXTM'^r\*'''n  ^fv-^"""™''  ^*^"'"-    .Carboniferous  Limestone     Dugno,  Rus^sia.     Longil 

SeTsi^KenerBaTetnear^;^^^^^^^^^       ^^^^^^°'   ^"^^^^^     "''^  (^^teV  Möller). '    .,   ^.  J^^e^^in^^^^: 


usually  wider  at  one  end,  hyaline  in  young,  thickened  with  age.     Cretaceous 
to  Recent. 


ORDER  Ti  FOEAMINIFERA  29 

Climacammina  Brady  (Crihrostomum  Möller),  (Fig.  15,  C,  D).  Test 
arenaceous  with  calcareous  basis.  Chambers  biserial,  rectilinear.  Oral  aper- 
ture  porous.     Abuiidaiit  in  Carboniferons  Limestoiie  (cf.  Bigenerina  d'Orb.). 

Siibfaiuily  C.     Verneuilininae  Cußliman. 
Test  cd  first  triserial,  later  biserial  or  even  uniserial  in  some  genera. 

Gaudryina  d'Orb.  (Fig.  14,  E).  Test  free,  early  portion  triserial,  later 
Chambers  arranged  biserially,  wall  usually  arenaceous. 

Clavulina  d'Orb.  (Fig.  14,  F).  Test  at  first  triserial,  latest  developed 
portion  uniserial.     Eocene  to  Recent. 

Valvulina  d'Orb.  (Fig.  15,  E).  Test  arenaceous  with  calcareous  basis. 
Chambers  in  triple  series  arranged  in  screw-like  spiral.  Qarboniferous  to 
Recent. 

Tetrataxis  Ehrbg.  (Fig.  15,  F).  Test  calcareous,  conical.  Alternating 
Chambers  arranged  in  a  turbinate  spire.     Carboniferous  Limestone. 

Siibfamily  D.      Bulimininae  Brady. 

Test  composed  of  Chambers  in  an  elongate  spiral,  aperture  elongate,  loop-shaped, 
usually  oblique,  lest  calcareous,  hyaline  in  young. 

Bulimina  d'Orb.  (Fig.  15,  J,  B).  Test  calcareous,  the  alternating 
Chambers  arranged  in  an  elongated  spire.     Triassic  to  Recent. 

Subfamily  E.     Cassidülininae  Brady. 

Test  with  the  Chambers  biserial  but  combined  with  a  spiral  or  volute  arrangement 
making  a  complex  lest. 

EhrenberginaRenss  (Fig.  15,  G).     Test  calcareous,  the  alternating  biserial 
Segments  either  completely  or  only  partially  coiled.     Tertiary  and  Recent. 
Cassidulina  d'Orb.     Tertiary  and  Recent. 

Family  5.     Chilostoniellidae. 

Test  calcareous,  finely  perforate,  composed  of  numerous  Chambers,  following  each 
other  from  the  same  end  of  the  long  axis,  or  alternately  from  the  two  ends,  or 
in  cycles  of  three. 

The  genera  Ellipsoidina  Seg.,  Chilostomella  and  Allomorphina  Reuss  compose 
this  family.     Cretaceous  to  Recent. 

Family  6.     Lagenidae  Carpenter. 

Test  calcareous,  vitreous,  finely  perforated,  one  or  more  Chambers  placed  in  a 
straight  line,  coiled  or  variously  arranged. 

< 
Subfamily  A.     Lageninae  Brady. 

Test  monothalamous,  flask-like. 

Lagena  Walker  (Fig.  16,  A).  Test  single-chambered,  spherical,  ovate  or 
flask-shaped,  with  terminal  oral  aperture.     Silurian  to  Recent. 


30 


PROTOZOA— RHIZOPODA 


PHYLUM  I 


Subfamily  ß.     Nodosarinae  Brady. 

Test  either  coiled  or  uniserial,  or  a  modification  of  one  or  the  other. 

Nodosaria  Lam.  (Fig.  1 6,  B).  Test  rod-shaped  ;  Chambers  arranged  in 
a  linear  series  and  set  off  from  one  another  by  constrictions ;  oral  aperture 
round,  terminal.     Abundant  and  widelv  distributed  from  Silurian  to  Recent. 


Fig.  16. 

A,  Lagena  semistriata  Williamson.  Antwerp  Crag  (Pliocene) ;  Antwerp.  B,  Nodosaria  spinicosta  d'Orb. 
Tegel  (Miocene);  Baden,  near  Vienna.  (',  Dentalina  elegans  d'Orh.  Same  locality.  D^Cristellariarotulata'La.m. 
Scapliiten- Pläner  (Turonian) ;  Boheniia.  E,  Va/jinulina  recta  Reuss.  Neoconiian  ;  Salzgitter,  Hanover.  F, 
LinguUna  costata  d'Orb.    Tegel  (Miocene) ;  Baden,  near  Vienna. 


Dentalina  d'Orb,    (Fig.    16,    6').      Like   the   preceding,    but   test   slightly 
arcuate.     Carboniferous  to  Recent. 

LinguUna  d'Orb.  (Fig.   1 6,  F).      Test  rectilinear,   compressed ;   segments 
regularly  attached;  aperture  terminal,  slit-like.     Trias  to  Recent. 

Glandulina  d'Orb.  (Fig.  17,  A).  Test  abbreviate,  ovate ;  segments  united 
in  rectilinear  series,  half  embracing  one  another.  General  aperture  round, 
terminal,  tubiform.     Trias  to  Recent. 

Faginulina  d'Orb.  (Fig.  16,  E).  Test  rectilinear,  laterally  compressed; 
segments  flattened,  with  obliquely  directed  septa.     Trias  to  Recent. 

Margin  ulina 
d'Orb.  Early  portion 
arched  or  helicoid, 
later  segments  recti- 
linear. Terminal 
aperture  slit  -  like. 
Trias  to  Recent. 

Cristellaria    Lam. 
(Fig.    16,  D).      Test 
regularly  planospiral, 
with        convolutions 
completely    envelop- 
ing  one  another.   Ter- 
minal aperture  round. 
Trias  to  Recent. 
Frondicularia  Defr.  (Fig.  1 7,  D).     Test  extremely  compressed  and  foliately 
expanded  in  a  single  plane;  Chambers  r^flexed  and  laterally  embracing  one 
another.     Terminal  aperture  round.     Trias  to  Recent. 


Ä,  Glandulina  inflata  Boruem.  Septarienthon  (Oligocene) ;  Hennsdorf. 
B,  Polymorphina  inflata  Williamson.  Recent ;  German  Ocean.  C,  Dimorphina 
sp.  Pliocene ;  Sienna,  Italy.  D,  Frondicularia  goldfussi  Reuss.  Scaphiten- 
Pläner  ;  Dülmen,  Westphalia.  E,  Uvigerina  p'ygmaea  d'Orb.  Tegel  (Miocene) ; 
Baden,  near  Vienna. 


ORDER  II 


FORAMINIFERA 


31 


Subtaiiiily  (J.      Polymorphininae  Brady. 

Test  composed  of  Chambers  arranged  spirally  or  irregularhj  ahout  the  long  axis ; 
aperture  usually  radiale. 

Polymorphina  d'Orb.  (Fig.  17,  B).  Segments  irregularly  helicoid,  or 
arranged  biserially,  more  or  less  enveloping  one  another  and  variable  in  shape. 
Terminal  aperture  round.     Trias  to  Recent. 

Dimorphina  d'Orb.  (Fig.  17,  C).  Early  Chambers  irregularly  or  triserially 
arranged,  later  ones  foUowing  in  rectilinear  fashion.     Cretaceous  to  Recent. 

Subfaniily  D.     Uvigerininae  Cnshman. 

Test  composed  of  Chambers  arranged  triserially  ahout  the  long  axis ;  aperture 
usually  simple,  with  a  deficite  neck  and  a  phialine  lip. 

Uvigerina  d'Orb.  (Fig.  17,  E).  Segments  dissimilar,  disposed  in  triple 
series,  and  spirally  wound  like  a  gastropod  shell.     Eocene  to  Recent. 

Subfamily  E.     Ramulininae  Brady. 

Test  composed  of  Chambers  with  long  tuhulariform  tubes. 

Ramulina  Rupert  Jones.  Test  branching,  consisting  of  rounded  Chambers 
joined  by  stolon-like  tubes.  Recent,  and  possibly  also  represented  in  the 
Cretaceous. 


Family  7.     Globigerinidae  Carpenter. 

Test  free,  calcareous,  perforated   by  coarse  tubules ;    monothalamous   or  poly- 
thalamous  ;  Chambers  globular,  either  irregularly  disposed  or  imperfectly  spiral. 

Of  the  tvvo  principal  genera  belonging  to  this  family,  Orbulina  d'Orb.  (Fig. 
18,  A)  is  unilocular,  and  GloUgerina  d'Orb.  (Fig.  18,  C)  is  multilocular.  The 
individual  Chambers 
usually  open  into  a 
common  central 
canal.  In  both 
genera  the  test  is 
often  covered  with 
extremely  delicate 
calcareous  spines, 
which,  however,  are 
very  easily  broken 
off,  and  are  never 
preserved  intact  in 
the  fossil  State. 
Both    these    genera 

are  excessively  abundant  in  existing  oceans  (Globigerina  ooze) ;  they  occur 
sparingly  in  the  Trias  and  throughout  the  Mesozoic,  first  becoming  important 
during  the  late  Tertiary. 

Sphaeroidina  d'Orb.  (Fig.  18,  B).     Characters  few,  so  coiled  as  to  form  a 
nearly  globular  test ;  aperture  with  a  valvulär  lip.     Cretaceous  to  Recent. 


Fig.  18. 

A,  Orhulina  universa  Lam.  Pliocene ;  Sieniia,  Italy,  B,  Sphaeroidina 
austriaca  d'Orb.  Miocene  Tegel ;  Baden,  near  Vienna,  C,  Globigerina  con- 
glomerata  Schwager.  Pliocene ;  Kar  Nikobar  Island,  a,  Inferior  siirface  ; 
h,  Superior  surface  ;  c,  Portion  of  periphery  ;  d,  Transverse  section  enlarged. 


32 


PROTOZOA— EHIZOPODA 


PHYLUM  I 


Family  8.     Rotalidae  Carpenter. 
Test  calcareous,  perforate,  free  or  adherent,  typicalhj  spiral  at  hast  in  the  young. 


Siibfamily  A.     Spirillininae  Brady. 

Test  a  flat  spiral,  without  divisions,  free  or  attached. 

Spirillina  Ehrenberg.  Test  a  planospiral  undivided  tube,  free  or  attached. 
Miocene  to  Recent. 

Subfamily  B.     Eotalinae  Carpenter. 

Test  calcareous,  rarely  arenaceous  or  siliceous,  finely  or  coarsely  perforated, 
frequently  with  intermediate  skeleton,  free  or  adherent,  turbinate  or  discoidal  in 
contour.  Segments  usually  arranged  in  an  elongated  spire,  although  in  some  forms 
irregularly 


Discorhina  Parker  and  Jones  (Fig.  19,  A,  B).     Test  coarsely  perforated, 


Fig.  19. 

Ä,  Discorhina  (Asterigerina)  planorbis  d'Orb.  Miocene  (Leithakalk)  ;  Nussdorf,  near  Vieima.  B,  Discorhina 
sp.  Recent.  a,  Under  side ;  h,  Upper  side ;  c,  Lateral  view  ;  (/,  Median  section.  C,  Planorhulina  mediter- 
ranensis  d'Orb.     Recent ;  Mediterranean.     a,  Inferior  surface  ;  h,  Superior  surface ;  c,  Transverse  section. 

turbinoid ;  lower  surface  broad  and  flat ;  umbilicus  often  filled  with  deposit 
of  intermediate  skeleton.     Cretaceous  to  Recent. 


Fig.  20. 

A,  Rotalia heccari  Lin.  Pliocene  ;  Sienna,  Italy.  B,  Pulvinulina  partsiM  d'Orb.  Miocene  (Tegel);  Baden, 
near  Vienna.  C,  Endothyra  panderi  Möller.  Carboniferous  Limestone;  Russia.  20/^,  j)^  Endothyra  parva 
Möller.     Lower  Carboniferous ;  Russia.     Longitudinal  section.     loo/^. 

Planorhulina  Parker  and  Jones  (Fig.  1 9  G).     Test  coarsely  perforated,  com- 
planate,  usually  attached,  upper  and  lower  surfaces  dissimilar  :  early  segments 


'UDER  II 


FORAMINIFERA 


33 


arranged  in  a  depressed  spire,  subsequeiitly  becoming  cyclical.  Lias  to 
Recent.  Various  subgeiiera,  named  by  d'Orbigny  Truncatulina,  Anomalina, 
Planulina,  etc.,  are  based  upon  slight  modifications  in  form. 

Rotalia  Lam.  (Fig.  20  Ä).  Test  finely  perforated,  with  segments  in  turbinoid 
spire.  Septa  composed  of  two  slightly  separated  lamellae,  with  anastomosing 
canals  occupying  the  intermediate  space.  Base  often  thickened  by  supplemental 
skeleton.     (?)  Silurian.     Upper  Jura  to  Recent. 

PulvinuUna  Parker  and  Jones  (Fig.  20  B). 
Rotaliform,  but  septa  simple  without  being  per- 
forated by  a  canal  System.    Lower  Lias  to  Recent. 

Endothyra  Phill.  (Fig.  20  C,  D).  Test  cal- 
careous,  composed  of  an  external  coarsely  per- 
forated and  an  internal  compact  layer,  the  latter 
finely  granulär;  segments  numerous,  coiled  in 
an  irregulär  spiral,  terminal  Chamber  opening  by 
several  apertures.  Abundant  in  Lower  Carbon- 
iferous,  and  existing  at  the  present  day,  ac- 
cording  to  Brady. 

Calcarina  d'Orb.  (Fig.  21).  Test  discoidal,  with  dissimilar  upper  and  lower 
surfaces ;  Chambers  spirally  coiled.  Exterior  encrusted  with  a  supplemental 
skeleton  which  fills  up  all  depressions  and  forms  spinous  or  spur-like  processes 
traversed  by  coarse  canals.  Upper  Cretaceous  to  Recent ;  very  abundant  in 
Maestricht  Chalk. 


Fig.  21. 

CalcMrina  calcitrapoides  Lam.  Upper 
Cretaceous  (Tuffkreide) ;  Maestricht, 
Holland. 


Siibfamily  C.      Tinoporinae  Brady. 

Test  of  irregularly  massed  Chambers,  the  early  anes  more  or  less  distinctly  spiral 
in  their  arrangement,  usually  without  a  general  aperture. 

Tinoporus  Montf.     Patellina  Williamson. 

The  Recent  genera  Carpenteria  Gray,  Rupertia  Jones,  etc.,  are  distinguished 
by  their  extremely  irregulär,  coarsely  perforated  and  usually  adherent  tests, 
which  sometimes  attain  considerable  size  and  often  contain  agglutinated, 
Sandy  or  various  other  foreign  particles.  Thalamopora  Roemer,  occurring  in 
the  Cretaceous,  probably  also  belongs  to  this  subfamily. 

Family  9,     Nummulitidae. 

Test  calcareous,  finely  tubulated,  polythalamous,  free,  spiral,  usually  bilaterally 
symmetrical. 

Subfamily  A.     Fusulininae  Brady. 

Test  fusiform  or  siibglobular  Chambers  extending  from  pole  to  pole,  each  convolu- 
tion  completely  covering  the  preceding  whorls. 


Schwagerina  Möller.  Test  spherical,  finely  perforated.  Primary  and 
secondary  septa  simple,  thin,  straight ;  secondary  chamberlets  communicating 
with  the  next  following  principal  chamber  by  means  of  a  basal  aperture. 
Abundant  in  Lower  Carboniferous  rocks  of  Japan,  China,  Sumatra,  North 
America  and  Russia. 

VOL.  I  D 


34 


PROTOZOA— RHIZOPODA 


PHYLÜM  I 


Fusulina    Fischer    (Fig.    22).       Test   fusiform,    laterally    elongated    like 
Alveolina,  coarsely  perforated.     Septa  of  principal  Chambers  undulating,  and 


Fig.  22. 

Ä,  Fxisulina  cylindrica  Fisch.  Carboniferous  Limestone  ;  Saranisk,  Russia.  Natural  size.  B,  C,  Same 
species  showing  various  cross-sections  enlarged.  D,  Enlarged  section  showing  Chambers  communicating  by 
means  of  foramina  (a,  b). 

united    so    as    to    form    secondary    chamberlets.       Excessively    abundant    in 
the  Lower  Carboniferous  of  Europe  (Russia),  Asia  and  North  America. 


Subfamily  B.      Polystomellinae  Brady. 

Test  Ulaterally  symmetrical,  nautiloid,  the  more  complex 
IS8    specimens  with  a  well-developed  secondary  canal  System. 


Fig.  23. 

Polystomella  crispa  Lam. 
Pliocene ;  Sienna,  Italy. 
(Highly  magnified.) 


Polystomella  Lamarck  (Fig.  23).  Test  regulär,  equi- 
lateral,  nautiloid,  final  whorl  alone  visible  from  the 
exterior.     Jurassic  to  Recent. 


Subfamily  C.     Nummulitinae  Brady. 

Test  lens-shaped  or  flattened,  higher  forms  with  complex  secondary  canal  System. 

Archaediscus  Brady.  Test  lenticular,  unsymmetrical,  spirally  coiled.  The 
Segments  irregularly  constricted  and  expanded  so  as  to  form  Chambers.  Septa 
and  canal-system  wanting.     Lower  Carboniferous. 


Fig.  24. 

Ämphisteginahaueri  d'Orb. 
Miocene  (Leithakalk) ;  Nuss- 
dorf,  near  Vieniia.  a,  Exterior 
Views,  enlarged  ;  h,  Natural 
size ;  c,  Median  section, 
greatly  enlarged  ;  d,  Trans- 
verse section,  greatly  en- 
larged. 


Fig.  25 


Operculina  complanata  (Ji&st.).  Miocene;  Bor- 
deaux, a,  Natural  size  ;  h,  c,  Median  and  longi- 
tudinal  sections,  greatly  enlarged. 


Heterostegina  costata  d'Orb. 
Miocene  (Leithakalk) ;  Nuss- 
dorf,  near  Vienna. 


Amphistegina  d'Orb.    (Fig.    24).      Test    lenticular,    slightly   inequilateral, 
spirally  rolled.     Whorls  divided  into  Chambers  by  numerous  single  septa  in 


ORDER  II  FORAMINIFERA  35 

which   canals  are  not  present;  solid  wedge-shaped   deposit  of   intermediate 


Fig.  27. 

Nummulites  cfr.  lucctsamts  Dfr.  Eocene ;  Kressenberg,  Upper  Uavaria.  Several  times  enlarged. 
a,  Marginal  cord  with  canal-system ;  ?^  Septal  plane  with  interseptal  canal-system ;  c,  Interior  of  Chamber  ; 
d,  Finely  perforate  periphery  ;  e,  Small  pillars  of  intermediate  skeleton. 

skeleton  near  the  umbilicus.     On  one  side  the  volutions  completely  enclose 

one  another  as  far  as  the  centre,  on  the  other  they  overlap 

only  partially  by  meaiis  of  alar  proloiigations  extending  in- 

wards.     Chambers  communicate  with  each  other  by  means 

of  a  slit  along  the  basis.     Miocene  to  Recent.     Particularly 

abundant  in  Miocene. 

Operculina  d'Orb.  (Fig.  25).  Test  discoidal,  complanate, 
composed  of  three  to  six  rapidly  expanding  spiral  whorls, 
which  are  polythalamous  and  non-involute.  Septa  and 
marginal  cord  traversed  by  a  direct  canal-system,  which  gives 
off  numerous  branches.  Cretaceous  to  Recent.  Particularly 
abundant  in  Eocene. 

Heterostegina  d'Orb.  (Fig.  26).     Like  Ojperculina,  but  with  Chambers  sub- 
divided  by  secondary  septa  into  chamberlets.     Tertiary  and  Recent. 


Fig;  28; 

Nummulites      (Assi- 
lina)   exponens 


Eocene 


Sow. 
Pyrenees. 


C  3  C'  1 2  Fig.  29. 

A  1  ••i,  Nummulites  (jizchensis  Ehrbg.  Eocene  ;  Libyan  Desert.  Natural  size.  A  -^  Specimen  with  eroded  peri- 
pheral  i)ortion,  showing  arrangement  of  septa.  B^^,  Nximmulites  laevigatus  Lam.  Calcaire  Grossier ;  Paris. 
Natural  size.  B'i,  Portion  of  same  enlarged.  C^^,  Nummulites  ramondl  Defr.  Eocene  (Nunimulitic  lime- 
stone);  Pyrenees.     Natural  size.     C  3,  Enlarged  section. 

Nummulites  Lam.  (Phacites  Blumenb. ;  Lenticulites  Lam.)  (Figs.  27-29).    Test 


36 


PROTOZOA— EHIZOPODA 


PHYLÜM  I 


symmetrically  leiiticular  or  discoidal,  composed  of  numerous  spirally  arranged 
polythalamous  volutions,  and  usually  with  columnar  intermediate  skeleton, 
which  forms  small  excresceiices  on  the  periphery.  The  septa  and  marginal 
cord  contain  a  coarse,  anastomosing  canal-system,  as  in  Operculina.  Primordial 
Chamber  spherical,  sometimes  large,  sometimes  exceedingly  minute  in  size. 
The  whorls  either  merely  embrace  one  another  {Ässilina)  (Fig.  28),  or  they 
completely   envelop  one   another    by   means  of   alar  prolongations  reaching 

inwards  to  the  centre  (Nummulina). 
The  septa  are  pierced  in  the  median 
plane  by  an  oblique  slit-like  aper- 
ture,  and  also  extend  into  the  saddle- 
shaped  alar  prolongations  of  the 
Chambers.  They  are  directed  in 
the  groups  Badiatae  and  Striatae  in 
straight  or  slightly  curved  lines 
(Figs.  27  and  29,  C) ;  in  the 
Sinuatae  they  follow  meandering 
courses  (Fig.  29,  A) ;  and  in  the 
Eeticulatae  (Fig.  29,  B)  they  form 
an  interlacing  network  by  means 
A,  Nummuiitic  limestone  with  horizontal  sections  of    of  connecting  processcs.     The  rami- 

N  distans  Fusch  Peyrehorade,  in  the  Pyrenees.  B,  fications  of  these  lateral  prOCeSSCS 
Nummuiitic  limestone  showing  sections  of  N.  lucasanus  w    «    wx    i.    v^  ^ 

Defr,   zakophane  in  the  Carpathians.  (filet    cloisomiaire)  may   be   rcadily 

Seen  on  fracturing  a  portion  of  the 
test,  and  are  a  valuable  aid  in  the  determination  of  species.  The  oldest 
Nummulites  {N.  pristinus  Brady)  occur  very  sparsely  in  the  Carboniferous 
limestone  and  Upper  Jurassic,  but  are  distinguished  from  the  typical  later 
forms  by  the  absence  of  an  interior  canal-system  in  the  marginal  cord.  The 
typical  Nummulites  which  are  so  characteristic  of  the  Eocene  (Nummuiitic 
limestone)  in  Europe,  North  Africa,  Asia  and  Central  America,  often  build  up 
massive  formations.  The  largest  species  (JV.  gizehensis  Ehrbg.,  N.  orUculatus 
Schaf h.)  attain  a  diameter  of  60  mm. ;  the  smallest  species  does  not  exceed 
2  mm.  ;  recent  representatives  comparatively  scarce. 


Subfamily  D.     Cycloclypeinae  Brady. 

Test  flat  with  a  thicJcened  centre,  or  lens-shaped,  consisting  of  a  diso  of  Chambers 
arranged  in  concentric  annuli  with  peripheral  thickenings,  septa  double  with  inter- 
septal  canals. 

Orbitoides  d'Orb.  {Hymenocyclus  Bronn;  Lycophrys  Monti.)  (Fig.  31).  Test 
discoidal,  with  circular  or  stellate  contour,  often  bent,  exterior  smooth  or  with 
radial  Striae,  and  composed  of  numerous  concentric  annuli  disposed  about  a 
primordial  spiral  of  three  to  five  whorls.  The  rings  are  divided  by  transverse 
partitions  into  small  rectangular  Chambers,  and  the  septa  and  marginal  cord 
are  traversed  by  canals.  Superimposed  over  the  median  series  of  principal 
Chambers  on  both  sides  are  several  layers  of  flattened  secondary  chamberlets, 
which  are  likewise  disposed  in  concentric  rings.  Very  abundant  in  the  Eocene, 
associated  with  Numm,ulites ;  rare  in  Upper  Cretaceous  and  Miocene. 

Cycloclypeus  Carp.     Miocene  and  Recent. 


»ER  II 


FORAMINIFERA 


37 


I 

^^B  Dawson,  Carpenter  and  various  other  authors  have  referred  the  so-called 

^^fozoon  occurring  in  crystalline  limestone  of  the  Archaean  (Laurentian)  period 

to  the  Foraminifera ;  biit  the  elaborate  investigations  of  Möbius  have  shown 


in,  liqn.  deL. 


Fig.  31. 


A,  Orbitoides  papyracea  Boubee.  Eocene  (Ferruginous  sandstone) ;  Kressenberg,  Upper  Bavaria,  (Greatly 
enlarged).  i  Median  Chambers  ;  2  Lateral  Chambers  ;  «  Compact  pillars  of  intermediate  skeleton.  B,  Portion  of 
median  transverse  seetion,  highly  magnified ;  2  Lateral  Chambers  with  perforate  walls  ;  4  Canal  -  System  of 
cyclical  marginal  cord  ;  ^Tabules  connecting  adjacent  Chambers.  C,  Periphery  and  profile  of  same,  natural 
size.  D,  Orbitoides  tenella  Gümbel.  Eocene  ;  Kressenberg,  (Natural  size).  E,  Orbitoides  variecostata  Gümbel; 
Eocene ;  San  Martino,  near  Verona.  (Natural  size.)  F,  Orbitoides  ephippium  Sow.  Eocene ;  Kressenberg. 
(Natural  size.) 

that  neither  Eozoon  nor  Archaeosphaerina  can  be  regarded  as  organic  structures, 
being  merely  mineral  segregations. 


Family  10.     Miliolidae  Carpenter. 

Test  of  one  or  more  Chambers,  calcareous  and  porcellanouSj  sometimes  covered  with 
sand,  usually  imperforate,  hut  in  some  forms  with  the  early  Chambers  distinctly 
perforate. 


Subfamily  A.     Cornuspirinae  Ciishman. 

Test  planospiral,  usually  of  a  proloculum  and  long  coiled 
Single  Chamber. 

Cornuspira  Schnitze  (Fig.  32).  Test  composed  of  numer- 
ous  plano-spiral  convolutions  ;  oral  aperture  simple,  terminal; 
monothalamous.     Lias  to  Recent. 


Fig.  32, 

Cornuspira  polygyra 
Reuss,  Oligocene ; 

Hungary. 


Subfamily  B.     Nubeculariinae  Brady. 

Test  irregulär  and  asymmetrical,  the  apertures  variously  placed. 

Nubecularia    Defrance.       Test  at  first  coiled,  later   tubulär  or   irregulär ; 
attached.     Liassic  to  Recent. 


38 


PEOTOZOA— EHIZOPODA 


PHYLÜM  I 


an\ 


Subfamily  C.      Häuerininae  Brady. 

First-formed  part  of  test   Cornuspii'a-like,  later   Chambers  Spiral  or  otherwise 
apertures  Single. 


Ophthalmidium  Kubier.  Early  Chambers  like  Cornuspira,  later  ones  two 
or  more  to  a  convolution,     Liassic  to  Eecent. 

Ilauerina  d'Orbigny.  Early  Chambers  Milioline,  later  ones  planospiral  with 
two  or  more  Chambers  to  a  convolution.     Cretaceous  to  Recent. 

Subfamily  D.     Miliolinae  Brady. 

Test  at  first  spiral,  then  eacli  whorl  divided  typically  into  two  Chambers,  laier 
Chambers  more  numerous  in  the  whorl  or  uniserial. 

Miliola  Lam.  (Figs.  33,  34).  Chambers  disposed  in  coil-shaped  loops 
about    a  few    spirally  wound    primordial  Chambers.     Each    Chamber   in   the 


Fig.  33. 
A,  Biloculina  inornata  d'Orb.     From  the  Miocene  Tegel ;  Baden,  near  Vienna.     B,  Triloculina  gibha  d'Orb. 
Oligocene  sand  from  Astrupp.    C,  Sjnroloculina  hadensii  d'Orb.     Miocene  Tegel ;  Baden,  near  Vienna.    D,  Quin- 
qüeloculina  saxorum  d'Orb.     Eocene  (Calcaire  Grossier) ;  Grignon,  near  Paris. 


Fig.  34 


A,  Longitudinal  section  of 
Biloculina  inornata  d'Orb. 
(enlarged).  B,  Transverse 
section  of  Quinquelomlina 
saxorum  d'Orb.  (enlarged). 


adult  forms  a  half  coil.  Terminal  pseudopodial  aperture  either  curving 
in  the  form  of  a  crescent  about  a  tooth-like  protection,  or  branching  den- 
dritically  (Lacazina).  Forms  having  all  the  segments  disposed  in  a  single 
plane,  and  all  externally  visible,  are  grouped  together  in  the  genus  Spirolocu- 
lina  d'Orbigny  ;  with  all  the  segments  completely  enveloping  one  another, 
Biloculina  d'Orb. ;    segments    disposed   in   three   or  in   five   dilferent  planes, 

Miliolina    AVill.    ( =  Trilocu- 

•=       ^^       lina      and      Quinqueloculina 

d'Orb.).     The  great  variety 

and     profusion     of     these 

genera    combine    to    make 

them    some    of    the    most 

important     of     the     rock- 

building  Foraminifera. 

Massive    beds    of    Eocene 

limestone      (Paris      basin, 

Pyrenees)  are  made  up  of 

Miliola    remains ;     at    the 

present       day      calcareous 

deposits   are  being  formed 

by  Biloculina  in  the  North  Sea  west  of  the  coast  of  Norway.     Miliola  first 

makes  its  appearance   in  the  Trias,  and  attains  its  maximum  development 

in  the  Tertiary  and  Recent  periods. 


Fig.  85. 

Fahularia  dis- 
colithes  Defr. 
Eocene  (Calcaire 
Grossier) ;  Paris. 


Fig.  36. 

Vertebralina  mu- 
cronata  d'Orb. 
Recent ;  Medi- 
terranean. 


ORDER  II 


FORAMINIFERA 


39 


Fahularia  Defr.  (Fig.  35).  Like  Biloculina,  but  relatively  larger.  General 
aperture  cribriform;  Chambers  not  an  empty  cavity,  but  filled  with  porcell- 
anous  or  calcareous  matter,  and  perforated  by  numerous  anastomosing  canals 
which  are  directed  parallel  with  the  axis  of  convolution.  Abundant  in  the 
Eocene  of  the  Paris  basin. 

Vertebralina  d'Orb.  (Fig.  36).  First-formed  portion  of  test  consisting  of 
coil-shaped  loops,  the  segments  afterwards  becoming  joined  in  rectilinear 
series.     Tertiary  and  Eecent. 

Idalina  Schlumb.  Last -for med  Chamber  completely  enveloping  all  pre- 
ceding  ones.     Cretaceous. 

Subfamily  E.     Peneroplinae  Brady. 

Test  planospiral  or  cycUcal,  and  bilaterally  symmetrical ;  apertures  many. 

Peneroplis  Montf.  (Fig.  37).  Test  discoidal,  complanate,  polythalamous ; 
direction  of  growth  primarily  spiral,  gradually  becoming  rectilinear,  while 
rapidly  increasing  in  width.  Septa  perforated  by  numerous  pores.  Tertiary 
and  Recent. 

A 


^^'V^T^r<-:W 


Fio.  37. 

Peneroplis  planatun 
Montfort.  Recent ; 
Mediterranean. 


Fig.  38. 

Orhiculina  nummis- 
7?mWsd'Orbigny.  Plio- 
cene ;  Sienna,  Italy. 


Fig.  39. 

A,  Orbitolites  complanata  Lam.  Eocene  (Cal- 
eaire  Grossier);  Paris.  B,  Portion  of  same  en- 
larged. 


Orhiculina  Lam.  (Fig.  38).  Test  discoidal,  first-formed  portion  spiral, 
afterwards  becoming  annular  ;  polythalamous ;  septation  regulär,  Chambers 
subdivided ;  septa  and  walls  of  segments  perforate.     Tertiary  and  Recent. 

Orbitolites  Lam.  (Fig.  39).  Test  discoidal,  circular  in  outline,  both  surfaces 
slightly  concave  in  the  middle,  attaining  comparatively  large  size,  and  com- 
posed  of  segments  which  are  arranged  concentrically  about  a  few  spirally 
coiled  primordial  Chambers.  Septa  radially  disposed,  and  perforated  by 
symmetrically  placed  pores.  In  the  more  complicated  forms  the  principal 
segments  are  invested  with  a  superficial  multilocular  layer,  the  Chambers  of 
which  are  also  arranged  in  concentric  rings  and  communicate  with  the 
principal  segments  by  means  of  pores.  An  important  rock-building  genus, 
ranging  from  the  Lias  onward.  0.  praecwsor  and  0.  circumvuha  Gümbel  are 
Jurassic,  0.  macropora  d'Orb.  Cretaceous,  and  0.  complanata  Lam.  Tertiary 
species. 

Subfamily  F.     Alveolininae  Br£f9y. 

Test  spiral,  elongated  in  the  direction  of  the  axis  of  coiling ;  Chambers  divided 
into  secondary  chamberlets.  ^,^-  '~ 

Aheolina  d'Orb.  (Borelis  Montf.)  (Fig.  40).  Test<fusiform,  elliptical  or 
spherical,  usually   elongated   in   the   axis   of    convolution,  and   composed   of 


40  PROTOZOA— RHIZOPODA  phylüm  i 

spirally  wound  segments  which  completely  envelop  one  another.  Eacti  Seg- 
ment is  partitioned  off  into  long,  narrow  Chambers  by  septa  arranged  at  right 
angles  to  the  axis,  and  these  are  subdivided  into  chamberlets  by  a  second 
set  of  septa  running  transversely  to  the  first  set.  Each  of  the  secondary 
chamberlets  communicates  with  the  adjacent  primary  Chamber  by  means  of  a 

Single  round  aperture.  In 
certain  Eecent  species  the 
secondary  chamberlets  are 
also      subdivided.  The 

genus  begins  in  the  Ceno- 
manian,    continues    in    ex- 
^^*'-  ^^-  traordinary  profusion,  and 

Älveolinahosci  d'Orh.     Eocene  (Calcaire  Grossier) ;  Paris.    ^.Frontal     hppnmpc:   n    mnQf  imnnrfnnf 
aspect.     B,  Test  laid  open  so  as  to  show  conformation  of  iuterior  ;     ^^^COmes  a    mOSt  importaut 

considerabiy  eniarged.  rock-builder  in  the  Eoccne. 

It  is  especially  abundant 
in  the  Calcaire  Grossier  of  the  Paris  basin,  the  Alveolina  limestone  of  Istria, 
Dalmatia,  Greece  and  the  Libyan  Desert. 

Siibfamily  G.     Keramosphaerinae  Brady, 

Test  spherical,  Chambers  arranged  in  concentric  layers. 

Keramosphaera  Brady.  Test  spherical,  Chambers  more  or  less  irregulär, 
in  concentric  layers.     Recent. 

Range  and  Distribution  of  Fossil  Foraminifera. 

More  than  2000  species  of  Foraminifera  have  been  described,  of  which 
number  about  two-thirds  are  known  in  a  fossil  State.  The  longevity  of 
certain  genera  and  species  is  remarkable,  many  of  them  persisting,  according 
to  Parker,  Jones,  Brady  and  others,  throughout  a  number  of  formations  of 
various  ages. 

The  earliest  forms  occur  very  sparingly  in  the  Silurian  of  St.  Petersburg, 
Siberia  and  Scotland.  They  are  for  the  most  part  poorly  preserved,  those 
from  Petersburg  being  recognisable  only  as  glauconitic  casts,  belonging  in 
part  to  siliceous  shell-bearing  genera  {Placopsilina,  Saccamina),  and  in  part  to 
vitreo-perforate  genera  (Nodosaria,  Lagena,  Glohigerina,  Rotalia).  The  Devonian 
is  also  very  poor  in  Foraminifera  remains  ;  but,  on  the  other  band,  the  Carboni- 
ferous  yields  an  abundant  and  considerabiy  varied  fauna ;  in  fact,  certain 
genera  (FusuUna,  Schwagerina,  Saccamina,  Endothyra)  build  up  limestone  de- 
posits  occasionally  of  great  thickness.  Numerous  representatives  of  the 
Lagenidae  {Nodosaria,  Dentalina,  etc.),  Textulariidae,  Rotalidae,  and  even  the 
Nummulitidae  accompany  the  rock-building  forms,  and  continue  for  the  most 
part  throughout  the  Permian.  Except  in  the  Alps,  the  Triassic  is  almost 
destitute  of  Foraminifera,  and  even  the  pure  limestones  and  dolomites  of  the 
Alpine  Trias  have  usually  become  so  altered  by  metamorphism  as  to  render 
the  recognition  of  tests  wellnigh  impossible.  Notwithstanding,  Globigerina 
limestone  lias  been  discovered  in  the  Upper  Triassic  of  the  Northern  Alps, 
and  tests  of  Cristellaria,  Marginulina,  Glohigerina,  Textularia,  Bilocidina,  etc.,  are 
found  in  the  St.  Cassian  beds. 

Certain  argillaceous  and  calcareous  strata  of  the  Lias  and  Jura  contain 
vast  quantities  of  minute,  vitreo-perforate  or  siliceous  Foraminifera.     In  the 


ORDER  III 


RADIOLARIA 


41 


etaceous,  Textalaria,  Eotalia,  Cristelläria,  Globigerina,  Miliola  and  coccoliths  are 
sential  constituents  of  the  AYhite  Chalk.  Individual  beds  of  the  Maestricht 
Chalk  consist  almost  entirely  of  Calcarina  remains ;  in  the  Urgo-Aptian  Orhi- 
tolina  is  the  chief  rock-builder ;  in  the  Upper  Cretaceous  Alveolina. 

The  maximum  development  of  the  Foraminifera  occurs  in  the  Tertiary 
period.  Massive  beds  of  the  Eocene  Calcaire  Grossier  of  the  Paris  basin  and 
in  the  Pyrenees  are  composed  of  Miliolidae  remains ;  other  Eocene  limestones 
consist  of  Alveolina,  Operculina,  Orbitolites  and  Orbitoides  aggregations.  But  of 
far  greater  geological  importance  are  the  Nummulites,  which  occur  in  incredible 
abundance  in  the  Eocene  and  Oligocene  Nummulites-formations  of  the  Medi- 
terranean  district,  Asia  Minor  and  Eastern  Asia. 

During  the  late  Tertiary  the  Nummulites  almost  entirely  disappear ;  only 
Amphistegina  continues  as  an  occasional  rock-builder,  and  from  the  middle 
and  later  Tertiary  on,  the  Foraminifera  fauna  remains  very  nearly  the  same 
as  now. 


Table  showing 

Geological 

Eange  of  the  Foraminifera 

Families 

ö 
.2 

Ö 

3 
§ 

ü 

1 

1 

CO 

1 

1-3 

1 

1 
1 

>> 

>> 

.2 

1 

1 

Gromidae 

Astrorhizidae 

Lituolidae 

Textulariidac 

Chilostomellidae 

Lagenidae 

Glohigerinidae 

Rotalidae 

Nummulitidae 

Miliolidae 

' 

1 

^         1 

[The  foregoiiig  chapter  on   Foraminifera  has  been  revised  for  the  preseut  work  by  Dr. 
Joseph  A.  Cushnian  of  the  Boston  Society  of  Natural  History,  Boston,  Mass.— Editor.] 


Orders.     RADIOLARIA   Müller.^ 

{Polycystina  Ehrenberg.) 

Marine  FJiizopoda  emitting  fine,  filiform,  radially  direded  pseudopodia,  with 
central  capsule  and  extra-capsulum,  and  usually  with  delicate  siliceous  skeleton. 

The  sarcode  body  of  the  Radiolarians  is  differentiated  into  (1)  an  inner 
central  sphere  or  capsule  of  tough  gelatinous-like  protoplasm  containing  one  or 

^  Literature  :  Ehrenberg,  G.,  Mikrogeologie,  1854  ;  also  memoirs  on  Radiolaria  from  Barbados, 
in  Al)handl.  Akad.  Wiss.  Berlin,  1872,  1875.— Haeckel,  K,  Die  Radiolarien,  lS62.—Jdem,  Report 
on  the  Radiolaria,  in  Scient.  Results  Cliallenger  Exped.,  Zool.,  vol.  xviii.,  1887. — Hertwig,  R.,  Der 


42  PROTOZOA— RHIZOPODA  phylum  i 

more  nuclei,  vacuoles,  alveoles,  granules,  oil- globales  and  sometimes  crystals 
and  surrounded  by  a  capsule-membrane  perforated  by  pores  or  pylae ;  and 
(2)  an  outer  jelly-like  extra-capsulum,  the  sarcode  of  which  emits  pseudopodia. 
The  individuals  lead  usually  an  isolated  existence,  and  are  only  rarely  united 
in  colonies. 

Most  Radiolarians  secrete  skeletons  composed  of  either  bars  or  spicules  of 
acanthine  (an  organic  substance  allied  to  hörn  or  chitin)  or  silica,  or  they  build 
an  exceedingly  delicate  lattice-work  composed  of  transparent  amorphous  silica. 
Only  the  latter  forms  are  known  in  a  fossil  State,  and  owing  to  their  minute 
size,  are  commonly  indiscernible  except  with  the  aid  of  the  microscope. 

Haeckel  divides  the  Radiolaria  into  four  suborders,  as  follows  : — 

A.  Acantharia. — Capsule-membrane  uniformly  perforated  ;  skeleton  com- 
posed of  acanthinic  spicules.     Unknown  in  fossil  State. 

B.  Spumellaria. — Capsule-membrane  single,  pores  distributed  all  over; 
skeleton  siliceous,  spherical  or  discoidal,  sometimes  wanting  (Fig.  43). 


Fig.  41. 
Silurian  and  Devonian  Radiolarians  :  A,  Cenosphaera  macropora  Rüst.     Ordovician  ;  Cabrieres,  Langnedoc. 
B,  Staurolo)iche  micropora,  Rüst.     Ordovician  ;  Cabrieres.     C,  Caryosphaera  groddecJd  Rüst.     Upper  Devonian  ; 
Schäbenholz,   near  Elbingerode,   Harz  Mountains.     D,  Lithocampe  tschernytscJie%ni  Rüst.     Devonian ;  Ural. 
Magnifted  100  to  120  diameters  (after  Rüst). 

C.  Nasselaria. — Capsule-membrane  single,  perforated  only  about  the  otäl 
pole  ;  skeleton  siliceous,  helmet-  or  cap-shaped,  conformation  of  poles  dissimilar 
(Figs.  44,  45). 

D.  Phaeodaria. — Capsule-membrane  double,  perforated  by  one  main  opening 
prolonged  into  a  tubulus,  and  by  a  few  smaller  accessory  openings.  A  dark 
pigment  body  (phaeodium)  constantly  present  in  extra-capsular  sarcode.  Skeleton 
commonly  consisting  of  hollow  siliceous  spicules  disposed  in  flask-shaped  or 
variously  shaped  frameworks.     Unknown  in  fossil  state. 

Radiolarians  are  exclusively  marine  organisms,  and  are  found  at  all  bathy- 
metric  zones.  They  occur  in  vast  numbers,  especially  in  tropical  seas, 
swimming  on  the  surface,  as  well  as  at  medium  and  even  abysmal  depths. 
Particularly  between  2000  and  4000  fathoms  in  depth,  extensive  deposits  of 
"  Radiolarian  mud  "  have  been  found,  the  composition  of  which  is  largely  silica 
with  a  small  percentage  of  carbonate  of  lime. 

Organismus  der  Radiolarien.  Jenaische  Denkschr.,  1879,  vol.  ii. — Stöhr,  E.,  Die  Eadiolarien- Fauna 
von  Grotte  in  Sicilien.  Palaeoutogr.,  1880,  vol.  xxvi, — Rüst,  D.,  Radiolarien  aus  Gesteinen  des 
Jura.  Palaeontogr.,  1885,  vol.  xxxi. — Idem,  op.  cit.,  vols.  xxxiv.  xxxviii.  and  Iv. — Dreyer,  F.,  Die 
Tripoli  von  Caltanisetta.  Jenaisclie  Zeitsclir.  f.  Naturw.,  1890,  vol.  xxiv. — Cayeux,  Z.,  Les  Preuves  de 
l'existence  d'organismes  dans  le  Precambrien.  Bull.  Soc.  Geol.  France,  1894,  vol.  xxii. — Vinassa 
de  Regny,  P.  E.,  Radiolarie  delle  flaniti  titoniane  di  Carpena  (Spezia).  Palaeont.  Italica,  1899,  vol. 
iv. — Hinde,  G.  J.,  Radiolaria  in  Devonian  Rocks  of  New  South  Wales.  Quart.  Journ.  Geol.  Soc, 
London,  1899,  vol.  \v.—Ideni,  Radiolaria  from  the  Triassic  of  the  Dutch  Fast  India  Archipelago. 
Jaarb.  Mijnwezen  Nederl.  Ooost  India,  1908,  vol.  xxxvii. — Squinabol,  S.,  Radiolarie  cretacee  degli 
Euganee.  Padova,  1904. — Principi,  P.,  Contributo  allo  studio  dei  radiolari  miocenici  italiani. 
Boll.  Soc.  Geol.  Ital.,  1910,  vol.  xxviii. 


ORDER  TU 


RADIOLARIA  43 

The  diversity  of  form  exhibited  by  Radiolarians  is  very  remarkable,  and 


Fig.  42. 
Carbotiiferous,  Jurassic,  and  Cretaceous  Radiolarians:  A,  Staur(u:ontium  ina^qualeRnsit. 


Carboniferous ; 
C,  Xiphodictyä  ac\äa  Rüst.     In  coprolite 


Sicily.'    B,   Trochodisctis  nicholsoni  Rüst.     Carboniferous;  Harz.     -,  -^  .  «„^-r^nA. 

from  Lias  ;  Ilsede,  Hanover.     D,  Hymenütatnm  rotvnditm  Rüst.     In  coprolite  from  Cretaceous  ;  /Uli,  öaxony. 

the  Identification  of  their  microscopic  siliceous  skeletons  is  impossible  without 
the  aid  of  special  literature.  Contrary  to  formerly  current  ideas,  the  geological 
antiquity  of  the 
Radiolarians  is  very 
great ;  and  they  also 
play  an  important 
part  in  the  cora- 
position  of  many 
siliceous  and  cal- 
careous-siliceous 
rocks  (quartzites, 
hornstone,  Jasper, 
phyllites,  Aptychen- 
schiefer,  etc.).  Ac- 
cording  to  Barrois 
they  are  the  oldest 
known  animal  or- 
ganisms,  since  the 
Spumellaria  (Mono- 
sphaeroidae)  occur 
plentifully  in  the 
bituminous  quartz- 
ites of  Brittany, 
interbedded  with 
pre  -  Cambrian 
gneiss. 

Although  the 
group  is  still  very 
imperfectly  known, 
yet,  according  to 
Rüst,  fossil  Radio- 
laria  are  by  no 
means  less  abundant  and  less  diversified  than  the  Recent 


Recent  and  Tertiary  Spumellarians :  A,  Adinomma  astenunnthium  Haeck. 
Recent ;  Messina.  B,  StylodictyamulHspina  J1aec\i.  Recent ;  Messina.  C,Helio- 
discus  Inimboldti  Ehrbg.  Barbados  eartli  (Miocene) ;  Barbados.  D,  Haliomma 
dixlphos  Ehrbg.  Miocene  marl ;  Caltan  isetta,  Sicily.  E,  Astromma  aristotdis 
Ehrbg.     Miooene ;  Barbados. 


Only  in  exceptional 


44 


PROTOZOA— EHIZOPODA 


PHYLUM  I 


Fig.  44. 

Recent  and  Tertiary  Nasselarians  :  A,  Podocyrtis  schcmiburgki  Ehrbg. 
Tertiary  marl ;  Barbados.  B,  Cyrtocalpis  amphora  Haeck.  Recent ; 
Messina.  C,  Bothryocampe  hexathalamia  Haeck.  Recent ;  Mediterranean. 
D,  Fetalospyris  foveolata  Ehrbg.     Tertiary  marl ;  Barbados. 


instances  (Miocene  of  Barbados,  Oran,  Sicily)  have  the  skeletons  been  preserved 
unaltered,  and  still  consist  of  amorphous  silica.  In  the  older  rocks  the  silica 
has  usually  become  dissipated  in  the  matrix,  being  replaced  by  lime  carbonate, 
iron,  or  some  colouring  agent ;  in  other  cases  the  quartz  has  become  crypto- 

crystalline,  or  replaced  by 
a  calcite  pseudomorph. 

The  Cambrian  Griffel- 
schiefer  of  Sonneberg  in 
Thuringia  contain  poorly 
preserved  Sphaeroidea  ;  the 
usually  dark,  though  some- 
times  red  or  light-coloured 
Ordovician  strata  of  Lan- 
genstriegis  in  Saxony,  and 
of  Rehau  and  Stehen  in 
Franconia,  the  red  Jasper 
of  Abington,  Scotland, 
and  the  Ordovician  sili- 
ceous  rocks  of  Cabrieres 
in  Languedoc,  are  more  or 
less  rieh  in  Radiolarian 
remains  belonging  exclusively  to  the  Spumellaria  (Fig.  4:1,  A,  B). 

From  the  Devonian  Jasper  of  Siberia,  the  siliceous  schists  of  Hesse  and 
Nassau,  and  the  manganiferous  quartzite  of  Elbingerode  in  the  Harz,  and 
other  places,  Rüst  has  described  forty-six  Spumellarian  species  and  seventeen 
Nasselarian  (Cyrtoidea).  The  Lower  Carboniferous  quartzites,  phyllites, 
adinole  and  Jaspers  from  the  Harz  (Culm  formation),  Ural  district  and  Sicily 
have  yielded  155  species,  of  which  thirty-six  belong  to  the  Nasselaria.  In 
general  the  Paleozoic  Radiolarians  are  remarkable  for  their  relatively  large 
size  and  excellent  preservation. 

The  Triassic  appears  to  be  destitute  of  Radiolarians  except  in  the  Alps, 
where  they  are  abun- 
dant  in  the  hornstone 
and  siliceous  lime- 
stone of  the  Buchen- 
stein beds  of  Hungary, 
and  occur  less  fre- 
quently  in  the  Rei- 
fling limestones,  in 
the  Wengen  beds  of 
Storzic  in  Carniola, 
in  the  marls  of  St. 
Cassian,  and  in  the 
siliceous  limestone  of 
the  Rötheistein,  near  Aussee,  etc.  They  are  usually  associated  here  with 
the  remains  of  Sponges  and  Foraminifera.  In  the  silicified  coprolites  of 
the  Lias,  found  at  Ilsede,  Hanover,  Radiolarians  are  very  common;  they 
are  somewhat  less  frequent  in  the  limestones  of  the  Lower  Lias  on  the 
Schafberg  in  Upper  Austria.  Certain  hornstone  beds  of  Middle  Jurassic 
age,    found    at    Piszke,    Hungary,    the    Upper    Jurassic    pudding-stones     of 


Fig.  45. 
Tertiary  Nasselarians  from  Barbados  :  Ä,  AntJwcyrtis  mespihis  Ehrbg.    B, 
Lychnocanium  lucerna  Ehrbg.     C,  Dictyomitra  montgolfieri  Ehrbg.     D,  Eucyr- 
tidium  elegans  Ehrbg.     E,  Pterocodon  campana  Ehrbg. 


ORDER  III  RADIOLARIA  45 

Cittiglio,  near  Laveno  on  Lago  Maggiore,  and  numerous  Tithoniaii  jaspars,  as 
well  as  the  Alpine  Aptychus  beds,  are  charged  with  Eadiolarians ;  here  the 
Nasselaria  are  nearly  as  plentiful  as  the  Spumellaria.  The  Lower  Cretaceous 
(Neocomian)  of  Gardenazza  has  yielded  but  few  forms.  On  the  other  hand, 
coprolites  from  the  Gault,  found  near  Zilli  in  Saxony,  and  Lower  Cretaceous 
clay  marls  in  Manitoba,  Canada,  as  well  as  from  Upper  Cretaceous  marls  of 
Haldem  in  Westphalia,  and  Vordorf  in  Brunswick,  contain  excellently  preserved 
skeletons  in  greater  or  less  abundance.  Even  the  flinty  concretions  of  the 
Upper  Chalk  sometimes  contain  them,  although  in  a  poor  State  of  preservation. 
Certain  Eocene  hornstones  in  Italy,  according  to  Pantanelli,  are  filled  with 
Radiolarian  remains,  while  in  the  Flysch  they  are  also  very  profuse  in  some 
localities,  although  usually  poorly  preserved. 

By  far  the  most  noted  occurrence  of  fossil  Radiolarians  is  in  the  siliceous 
"  Barbados  earth,"  of  Miocene  age,  in  which  Foraminifera  are  also  very  con- 
spicuous ;  while  the  "  tripoli "  of  Grotte,  Caltanisetta  and  Girgenti  in  Sicily, 
of  Oran,  Aegina,  Zante,  the  Nikobar  Islands  and  other  localities  (Miocene  and 
Pliocene),  is  scarcely  less  noteworthy.  Ehrenberg  has  described  278  species 
from  Barbados  alone,  and  from  Sicily  Stöhr  has  described  118  species,  most  of 
which  belong  to  still  extant  Spumellarian,  Nasselarian  and  Phaeodarian  genera. 


Phylumll.    COELENTERATA. 

CoELENTERATES  or  Zoophytes  are  free-swimming  or  attached  aquatic  animals 
of  very  variable  form  and  size.  They  difFer  from  the  Protozoa  in  having 
multicellular  bodies  with  distinct  organs ;  and  from  all  higher  classes  in  the 
absence  of  a  definite  body-cavity.  In  the  subphylum  Porifera  there  is  a 
simple  or  usually  complex  System  of  digestive  sacs,  with  inhalent  pores  in  the 
body  wall  and  one  or  many  exhalent  pores  or  oscula,  and  no  stinging  cells  or 
tentacles.  The  two  other  subphyla,  Cnidaria  and  Ctenophora,  exhibit  a  more 
or  less  pronounced  radial  symmetry,  have  no  inhalent  pores  and  no  special 
exhalent  opening  in  the  body  wall,  but  a  large  mouth  opening  conducts  into  a 
gastrovascular  cavity.  Food  is  taken  in  and  the  excreta  and  sexual  elements 
are  voided  through  the  mouth  opening.  Stinging  cells  and  usually  tentacles 
are  present  in  the  two  last-named  divisions. 

The  body  consists  of  two  layers  of  cells  —  an  ectoderm  and  entoderm — 
and  usually  also  a  third  layer,  the  mesoderm.  The  ectoderm  in  the  Cnidaria 
often  secretes  a  calcareous  or  horny  skeleton,  but  in  the  Porifera  the  horny, 
siliceous  br  calcareous  skeletal  elements  are  the  product  of  the  mesoderm. 

Eeproduction  is  either  sexual  or  asexual,  or,  in  the  Hydrozoa,  an  alterna- 
tion  of  generations  may  occur.  The  process  of  budding  or  self-division  gives 
rise  to  polyzooid  colonies,  in  which  the  zooids  subsist  in  intimate  relationships 
with  one  another,  and  sometimes  Institute  a  physiological  division  of  labour. 

R.  Leuckart  was  the  first  to  recognise  the  Coelenterates  as  constituting  a 
distinct  structural  type  of  animals  and  separated  them  from  the  Echinoderms, 
with  which  the  older  systematists  had  associated  them  under  the  general  term 
of  Radiates  or  Actinozoa.  The  Coelenterates  are  divided  into  three  principal 
groups  or  subphyla  :  Porifera,  Cnidaria  and  Ctenophora.  Of  these  only  the  first 
two  have  skeletons  and  have  left  traces  in  the  rocks. 

Subphylum  L     Porifera  Hogg. 

The  Porifera  or  Sponges  are  sessile,  aquatic  animals  of  extremely  variable 
form.  The  body  consists  of  a  single  layer  of  pavement-cells  forming  the 
ectoderm,  a  single  layer  of  collared  epithelial  cells  constituting  the  entoderm, 
and  usually  a  strongly  developed  mesoderm,  which  latter  comprises  the  bulk  of 
the  soft  parts  (including  all  the  organs,  muscles,  sexual  elements  and  nerves), 
and  almost  invariably  secretes  a  hard  skeleton.  The  latter  may  consist  of 
horny  sponge-fibres,  or  of  regularly  disposed  siliceous  or  calcareous  skeletal 
elements.  The  whole  body  is  ramified  by  a  canal-system,  and  the  outer 
epithelial  layer  is  perforated  by  countless  minute,  dermal  pores  for  the  entrance 
of  water  laden  with  food-particles.     The  pores  communicate  by  means  of  fine 

46 


CLASS  I  SPONGIAE  47 


f 

Hei 


curreiit  canals  with  subdermal  ciliated  Chambers,  from  which  larger  exciirrent 
nals  coiiduct  the  water  and  food  or  excreta  through  the  body,  and  generally 
en  into  a  wide,  exhalent  opening  called  the  cloaca  or  paragaster.  Stinging 
11s,  tentacles  and  radial  mesenteries  are  absent.  The  Porifera  comprise  but 
one  class,  the  Sponges. 


Olass  1.     SPONGIAE.     Sponges.i 

Sponges  are  remarkable  for  their  extreme  variability  in  external  form 
and  size ;  they  lead  either  an  isolated  existence,  or  are  united  in  colonies  of 
cylindrical,  tubulate,  pyriform,  fungns-like,  bulbous,  spherical,  compressed, 
foliate,  umbel-,  bowl-  or  beaker-shaped,  or  of  botryoidal  form.  They  are  long- 
or  short-stemraed,  or  a  peduncle  may  be  absent ;  sometimes  the  stock  is 
branching,  and  the  arms  may  be  either  separate  or  interlaced  so  as  to  form 
networks.  Nothing  is  less  stable  than  the  outer  conformation,  which  varies 
excessively  aecording  to  the  Situation  and  other  physical  conditions,  and 
whose  systematic  importance,  accordingly,  is  very  slight.  The  size  is  also 
extremely  variable,  ranging  from  that  of  a  pin-head  to  1 J  metres  in  diameter. 

Sponges  are  invariably  sessile  in  habit,  being  attached  either  by  means  of 
a  stem  or  a  bündle  of  anchoring  spicules,  or  they  may  be  simply  encrusting 
at  the  base. 

The  canal-system  by  which  the  whole  body  is  traversed,  is  extremely  com- 
plicated  in  thick-walled,  but  simple  in  thin-walled  sponges.  A  distinction  is 
recognised  between  incurrent  or  inhalent,  and  excurrent  or  exhalent  canals. 
In  the  terminology  proposed  by  Rauff,  inhalent  canals  are  designated  as 
epirrhysa,  and  exhalent  canals  as  aporrhysa ;  the  former  terminate  on  the 
periphery  in  ostia  (not  to  be  confounded  with  the  finer  dermal  pores),  while 
the  latter  terminate  on  the  cloacal  surface  in  postica  (again  not  to  be  con- 
founded with  gastral  pores).  Postica  are  usually  larger  than  ostia,  and 
differ  from  them  in  form  and  arrangement. 

^  Literature  :  ^.  On  receut  Sponges  : — 

Schmidt  O.,  Die  Spoiigien  des  Adriatischen  Meeres.  Leipzic,  1864-66. — Ide7)i,  Die  Spongien  der 
Küste  von  Algier.  Leipzic,  1868. — Idem,  Die  Spongien  des  Meerbusens  von  Mexico.  Jena,  1879-80. 
— Haeckel,  £.,  Die  Kalkschwämme,  1872. — Schulze,  Fr.  Iß.,  Untersuchungen  über  den  Bau 
und  die  Entwicklung  der  Spongien.  Zeitschr.  f.  wiss.  Zool.,  1876-80,  vols.  xxvii.  -  xxx. — 
Report  on  the  Hexactinellida.  Scient.  Results  Challenger  Exped.,  Zool,,  vol.  xxi.,  1887. — 
Vosmaer,  G.  C.  J.,  Spongien  {Porifera),  in  Bronn's  Classen  und  Ordnungen  des  Tierreichs, 
2nd  ed.,  1882-87,  vol.  iii. — Lendenfeld,  R.,  A  Monograph  of  the  Horny  Sponges.     London,  1889. 

B.  On  fossil  Sponges  : — 

Ooldfuss,  A.,  Petrefacta  Germaniae,  vol.  i.,  1826-33. — Michelin,  H.,  Iconographie  zoophyto- 
logique,  1840-47. — Fromentel,  E.  de,  Introduction  ä  l'etude  des  eponges  fossiles.  Mem.  Soc.  Linn. 
Normandie,  1859,  vol.  xi. — Roemer,  F.  A.,  Die  Spongitarien  des  norddeutschen  Kreidegebirges. 
Palaeontographica,  1864,  vol.  xiii. — Zittel,  K.  A.,  Ueber  Coeloptychium.  Abhandl.  k.  bayer. 
Akad.,  1876,  vol.  xiii. — Studien  über  fossilen  Spongien,  i.,  ii.,  iii.,  ibid.,  1877,  vol.  xiii.  (translated 
by  Dallas  in  Annais  and  Mag,  of  Nat.  Hist.  for  1877,  1878,  1879). — Beiträge  zur  Systematik  der 
fossilen  Spongien,  i,,  ii,,  iii.,  Neues  Jahrb.  für  Mineral.  1877,  1878,  l^l^.—Quenstedt  F.  A., 
Petrefactenkunde  Deutschlands,  1877,  vol.  v. — Sollas,  W.  J.,  Quart.  Journ.  Geol.  Soc.  1877-80, 
vols.  xxxiii.  -  xxxvi, — Hinde,  G.  J.,  Catalogue  of  fossil  Sponges  of  British  Museum,  London, 
1883.— Monograph  of  British  fossil  sponges  ;  Palaeontographical  Society,  1887,  1888,  1893. — 
Rmtff,  H.,  Palaeospongiologie  ;  Palaeontographica,  1893-94,  vols.  xl.,  xli.  (contains  füll 
bibliography). — Schrammen,  A.,  Beitrag  zur  Kenntniss  der  obersenonen  Tetractinelliden.  Mittheil. 
Roemer.  Museum  Hildesheim,  1899-1903,  Nos.  10,  14,  15,  19.— Hall,  J.  and  Clarke,  J.  M., 
A  Memoir  on  the  Palaeozoic  reticulate  Sponges  constituting  the  family  Dictyospongidae.  N.  Y. 
State  Mus.  Mem.  ii.,  1898.  Earlier  contributions  by  same  authors  in  loth  and  16th  Reports  N.  Y. 
State  Geologist,  1895-96. — Schrammen,  A.,  Kieselspongien  der  oberen  Kreide  von  Nord  Westdeutsch- 
land. Palaeontogr.  1910,  Supplem.  vol.  v. — Kolb,  R.,  Kieselspongien  des  schwäbischen  weissen 
Jura.     Op.  dt.,  1911,  vol.  Ivii. 


48  COELENTERATA— PORIFERA  phylum  ii 

The  water  enters  through  the  dermal  pores,  and  passes  through  the 
incurrent  canals  into  ciliated  Chambers,  which  are  lined  with  epithelial  cells. 
From  these  it  is  conveyed  through  all  parts  of  the  body  by  means  of  the 
frequently  branching  excurrent  canals,  which  open  into  a  sac-like,  tube-like 
or  funnel-shaped  cloaca.  The  exhalent  opening  of  the  latter  is  termed  the 
osculum.  Extremely  thin-walled  sponges  have  no  cloaca,  osculum  or  branch- 
ing canal-system,  but  the  excurrent  canals  terminate  directly  in  small  openings 
situated  on  the  upper  surface  of  the  body.  The  cloaca  when  present  is  often 
of  considerable  depth,  although  sometimes  shallow,  or  reduced  to  a  mere  sac-like 
Prolongation  of  the  osculum.  Forms  with  a  large  and  deep  cloaca  are  regarded 
as  Single  individuals,  those  with  numerous  cloacae  and  oscula  as  colonies.  But 
since  all  the  cloacae  of  a  colony  communicate  by  means  of  canals,  while  the 
oscula  are  never  surrounded  by  a  crown  of  tentacles,  it  is  often  difficult  to 
distinguish  between  large  excurrent  canals  and  true  cloaca,  and  hence  also 
between  individuals  and  colonies. 

Reproduction  is  either  sexual  or  asexual.  In  the  first  process  the  fertilised 
ova  complete  a  tolerably  regulär  segmentation,  develop  into  a  gastrula,  pass 
out  through  the  osculum,  and  attach  themselves  to  some  foreign  object. 
Asexual  reproduction  takes  place  by  budding,  the  young  buds  remaining 
attached  to  the  parent  individual,  and  thus  giving  rise  to  colonies.  Re- 
production by  means  of  fission  forming  new  colonies  is  of  rare  occurrence. 

The  great  majority  of  sponges  secrete  a  skeleton  composed  either  of  horny 
fibres  or  of  siliceous  or  calcareous  spicules,  or  they  incorporate  foreign  bodies 
into  their  framework.  Only  a  few  Recent  forms  (Myxospongiae)  are  without 
a  skeleton.  In  the  horny  sponges  (Ceratosponyiae)  the  skeleton  consists  of 
anastomosing  and  reticulated  fibres  of  spongin,  an  organic  nitrogen  Compound 
resembling  silk.  The  fibres  are  either  solid,  or  they  contain  an  axial  canal, 
which  is  sometimes  cored  with  foreign  bodies,  such  as  sand-grains,  fragments 
of  sponge-spicules,  foraminifers,  radiolarians,  etc. 

Siliceous  spicules  are  sometimes  encased  in  horny  fibres,  sometimes  occur 
detached  in  the  cellular  tissues,  or  are  interlaced  and  Consolidated  with  one 
another  in  various  ways  to  form  a  supporting  framework.  In  each  genus  the 
skeleton  is  composed  of  but  a  single  type,  or  at  the  most  of  but  a  few  regularly 
repeated  varieties  of  siliceous  bodies,  which  are  called  the  skeletal  elements.  In 
addition  to  these  there  occur  more  or  less  abundantly,  especially  on  the  outer 
surface  and  in  the  cloacal  and  canal  walls,  extremely  delicate  flesh-spicules, 
usually  of  small  size  and  of  great  diversity  of  form.  The  flesh-spicules  are  as 
a  rule  destroyed  during  fossilisation.  All  the  siliceous  skeletal  elements  are 
secreted  by  nucleated  cells,  and  are  composed  of  concentric  layers  of  colloidal 
silica,  deposited  usually  about  a  slender  axial  canal.  In  some  spicules,  notably 
those  having  spherical  or  stellate  contours,  the  axial  canal  is  wanting.  It  is 
very  delicate  in  fresh  spicules,  but  becomes  enlarged  by  maceration,  and  in 
fossil  speciraens  it  is  often  coarsely  calibrated. 

The  multitudinous  varieties  of  siliceous  skeletal  elements  (Fig.  46)  may 
be  grouped  into  a  few  fundamental  types,  as  follows  : — 

{a)  Uniaxial  spicules  or  monaxons  (Fig.  46  ^'^^)  and  (^'^"^^).  Straight  or 
bent,  smooth,  prickly  or  knotty,  bevelled,  sharpened  or  truncated  needles, 
rods,  hooks,  clasps,  pins  and  anchors  (amphidiscs).  They  invariably  contain 
an  axial  canal,  which  may  be  either  entirely  sealed  up,  or  open  at  one  or  at 
both  ends. 


}S  I 


SPONGIAE 


49 


I 

^^m  (b)  Tetraxial  spicules  or  tetraxons  (Fig.  46  ^^).  The  normal  form  is 
^Waracterised  by  four  equal  rays  intersecting  like  the  bisectrices  of  the  plane 
angles  of  a  regulär  tetrahedron.  Triaxial  forms  result  from  the  occasional 
abortion  of  one  of  the  rays.  One  of  the  rays  may  become  elongated  or  other- 
wise  modified  so  as  to  form  anchors  (triaens)  with  three  simple  or  furcate  hooks 
(Fig.  46  18-23^^  Three  of  the  rays  may  be  numerously  divided  or  foliately 
expanded  so  as  to  produce  forms  resembling  thumb-tacks  {trichotriaens,  phyllo- 
triaens) ;  atrophy  of  the  fourth  ray  in  the  last-named  form  reduces  the  spicule 
to  a  delicate  siliceous  disk  (Fig.  46  ^).  A  peculiar  forking  of  the  shaft  gives 
rise  to  candelabras  or  amphitriaens,  while  other  modifications  may  produce 
umbellate  spicules  (Fig.  46  ^^),  etc. 

Certain  skeletal  Clements  of  the  Lithistids  (Figs.  48-63)  may  be  regarded 
as  irregulär  tetraxons  {desmoms),  in  which  the  extremities  of  the  four  rays  are 


Fio.  46. 
Varlous  forms  of  Sponge  spicules  from  the  Upper  Cretaceous  of  Haldem,  Westphalia  ;  magnified  25  diameters. 
1-6,  Uniaxial  rod.s  and  needles.  7-9,  Uniaxial  siliceous  elements  with  coarse  axial  canals.  10-13,  Uniaxial 
cylinders  and  spheres.  14,  Microspined  spicule.  15,  Clasp-hook  flesh-spicule.  16,  Bispatulate  tlesh-spicule. 
17,  llegular  four-rayed  spicule  (chevauxde  frise).  18-21,  Trifld  anclior-shaped  spicules.  22-23,  Anchors  with 
furcate  head-rays.  24-25,  Irregulär  four-rayed  skeletal  elements.  26,  Umbel-shaped  spicule.  27,  Six-rayed 
spicule.     28,  Polyaxial  siliceous  disk. 

prolonged  in  knotty,  root-like  excrescences,  or  in  which,  owing  to  the  un- 
symmetrical  growth,  branching  or  atrophy  of  one  or  more  of  the  arms, 
extremely  irregulär  forms  are  produced ;  for  these  a  special  terminology  has 
been  devised  by  Rauff. 

(c)  Hexactinellid  spicules  (hexadins  or  triaxons)  (Figs.  65-70).  The 
ground-form  is  an  axial  cross  with  six  equal  arms  intersecting  at  right  angles 
like  the  axes  of  a  regulär  octahedron.  Atrophy  of  one  or  more  of  the  rays 
may  result  in  pentaxial,  tetraxial,  triaxial,  or  even  clavate  forms,  without  their 
real  character  becoming  entirely  obliterated.  Bifurcation  or  other  modifica- 
tions of  a  number  or  of  all  the  rays  produce  beautifully  formed  siliceous 
structures  highly  characteristic  of  the  group  IlexadineUida,  which  resemble 
candelabras,  double-headed  anchors,  fir-trees,  pitch-forks,  rosettes,  etc.  The 
fusion  of  juxtaposed  hexactins  produces  more  or  less  symmetrical  latticeworks 
with  cubical  interstices. 

VOL.  I  K 


50  COELENTERATA— POEIFERA  phylum  i 

{d)  Anaxial  or  polyaxial  bodies  of  spherical,  cylindrical,  stellate  or 
discoidal  shape,  which  are  not  derivable  from  either  of  the  tliree  ground-forms, 
occur  in  only  a  few  varieties  of  recent  and  fossil  siliceous  sponges. 

Calcareous  skeletal  elements  are  much  less  complicated,  and  are  generally 
smaller  and  more  perishable  than  the  siliceous.  Their  form  is  either  triaxial 
(triods),  tetraxial  (tetraxons),  or  nail-shaped  (monaxons).  The  triaxial  and 
tetraxial  spicules  are  very  rarely  forked  or  otherwise  modified.  Each  skeletal 
element  behaves  optically  like  a  single  calcite  crystal ;  axial  canals  are  absent. 

The  skeletal  elements  in  sponges  are  arranged  chiefly  with  reference  to  the 
circulation  of  water  through  the  canal-systems.  In  thin-walled  forms  they  are 
more  or  less  closely  crowded  together,  and  are  often  regularly  oriented  in  the 
soft  parts ;  in  other  forms  they  are  encased  in  horny  fibres,  or  are  packed  in 
between  the  canals ;  in  still  others  they  are  united  to  form  an  irregulär  frame- 
work,  or  may  be  welded  together  in  a  regularly  reticulated  scaffolding. 

The  horny  fibres  are  totally  destroyed  during  fossilisation ;  calcareous 
spicules  are  often  wholly  or  partially  dissolved,  or  are  replaced  by  infiltrating 
lime  carbonate,  and  assume  a  dense  fibrous  appearance  (Fharetrones).  Like- 
wise  in  siliceous  sponges  the  skeletal  elements  are  rarely  preserved  unaltered  ; 
as  a  rule  the  originally  colloidal  silica  becomes  crystalline,  or  is  dissolved  and 
removed.  The  cavities  thus  formed  may  subsequently  become  filled  with 
infiltrating  quartz,  limonite  or  most  commonly  with  lime  carbonate.  In 
this  manner  the  skeletons  of  fossil  siliceous  sponges  are  converted  into  calcite, 
and,  contrariwise,  spicules  that  were  originally  calcareous  may  become  silicified. 
Hence  the  distinction  between  siliceous  and  calcareous  sponges  in  the  fossil 
State  depends  entirely  upon  morphological  characters,  and  not  at  all  upon  the 
chemical  composition  of  the  preserved  parts. 

Sponges  are  divided  into  four  subclasses  :  Myxospongme,  Ceratospongiae, 
Silicispongiae  and  Calcispongiae.  The  latter  group  Stands  in  sharp  contrast  to 
the  other  three,  which  are  connected  by  intermediate  forms,  and  constitute 
together  a  'group  of  equal  value  with  the  calcareous  sponges.  Skeletal 
elements  are  absent  in  the  Myxospongiae,  whose  bodies  are  composed  entirely 
of  soft  cellular  tissues.  The  Ceratospongiae  also  lack  imperishable  hard  parts, 
the  spongin  fibres  being  entirely  destroyed  during  fossilisation.  The  reputed 
horny  sponges  from  the  Trias  (EhizocoraUum),  Jura  and  Cretaceous  (Spongites, 
Saxonicus,  Paramudra,  etc.)  are  either  of  inorganic  nature  or  are  zoologically 
indeterminate.  All  fossil  sponges,  therefore,  belong  either  to  the  Silicispongiae 
or  the  Calcispongiae.  The  oldest  forms  are  found  in  the  Cambrian  ;  in  the 
Trias,  Jura  and  Cretaceous  they  are  very  abundant. 

Subclass  3.     SILICISPONGIAE.     Siliceous  sponges. 

Skeleton  composed  either  exclusively  of  siliceous  elements,  or  of  horny  fihres  enclos- 
ing  siliceous  spicules. 

Order  1.     MONAGTINBLLIDA   Zittel. 
{Monaxonia  F.  E.  Schulze.) 

All  skeletal  elements  uniaxial. 
The  Monactinellida  include  the  majority  of  existing  marine  sponges,  most 
of  which  occur  at  moderate  de23ths ;    and    also    the    few    fresh-water    forms 


ORDER  II 


SILICISPONGIAE— TETRACTINELLIDA 


51 


(Spongilla)  that  are  known.  The  skeleton,  as  a  rule,  is  composed  like  that 
of  the  horny  sponges,  of  anastomosing  spongin  fibres,  which  either  encase 
rod-like  spicules,  or  coiitain  quantities  of  iiniaxial  siliceous  elements  ;  some- 
times  the  latter  are  also  present  in  the  soft  parts.  In  each  genus  there  are 
usually  either  one  or  but  few  varieties  of  siliceous  elements  present,  which  are  uni- 
formly  distributed  throughout  the  body.  Needles,  hooks,  crotchets,  cylinders, 
spindles,  amphidiscs  and  the  like  occur  in  great  diversity.  Owing  to  the 
decomposition  of  the  horny  fibres  during  fossilisation,  and  the  fact  that  the 
skeletal  elements  are  never  fused  together,  the  latter  become  detached  and 
scattered  in  all  directions.  While  Monactinellid  spicules  are  very  common 
in  certain  formations,  they  are  rarely  united  in  the  form  of  coherent 
skeletons,  and  are  only  capable  of  generic  determination  when  their  form  is 
sufficiently  characteristic,  as  in  Eenieria,  Esperia,  etc.  The  basal  beds  of  the 
Alpine  Lias  often  contain  considerable  hornstone,  which  is  sometimes  com- 
pletely  filled  with  rod-shaped  spicules.  In  various  Cretaceous  and  Tertiary 
horizons  Monactinellid  spicules  are  also  enormously  abundant.  Hinde  has 
described  a  Climacospongia  from  the  Silurian  of  Tennessee,  in  which  the 
skeleton  consists  of  spicules  arranged  in  longitudinal  rows,  and  connected  by 
transversely  disposed  elements.  The  spicules  were  probably  originally 
enclosed  in  horny  fibres.  The  Clionidae  secrete  pin-shaped  siliceous  elements 
which  are  also  encased  in  horny  fibres,  and  Recent  sponges  of  this  family 
bore  labyrinthic  passages  in  the  shells  of  mollusks.  Fossil  sponge-borings  are 
also  common.  Detached  spicules  of  Eenieria,  Axinella  and  Haplistion  have 
been  described  by  Hinde  from  the  English  Carboniferous  Limestone. 


Order  2.     TETRACTINELLIDA    Marshall. 

(Tetraxonia  F.  E.  Schulze.) 

Skeleton  composed  of  regulär  tetraxons  which  are  generally  combined  with  uni- 
axial, polyaxial  or  heteraxial  siliceous  bodies.       The 
skeletal  elements  occur  detached  throughout  the  soft 
parts,  and  are  never  united  to  form  a  connected  frame- 
work. 

The  most  common  forms  of  skeletal  elements 
are  normal  tetraxons,  anchors  with  simple  or 
furcate  prongs,  spheres  and  stellate  bodies.  In 
certain  genera  (Geodia)  the  large  anchors  and 
cylinders  are  disposed  in  radiately  arranged  fasci- 
cles,  and  are  surrounded  by  a  thick  layer  of 
anaxial  spheres. 

Detached  Tetractinellid  spicules  associated 
with  Monactinellids  occur  more  or  less  abundantly 
in  the  Carboniferous  Limestone,  the  Alpine  Infra- 
Lias,  the  English  Neocomain,  the  Deister  Sand- 
stone (Hils),  the  Upper  Cretaceous  of  Haldem 
and  Coesfeld  in  Westphalia,  and  in  the  Tertiary 
and  Pleistocene  formations.  The  skeletal  elements  are  preserved  in  their 
natural  position  in  the  genera  Ophiraphidites  Carter  ;  Tethyopsis  Zittel  (Fig.  47), 
Pachastrella  Schmidt,  Stolleya  and  Cephaloraphidites  Schrammen. 


Fio.  47. 

Tethyopsis  steinmanni   Zittel.      Upper 
Cretaceous  ;  Ahlten,  Hanover.    14/^. 


52 


COELENTERATA— PORIFEEA 


PHYLÜM  II 


Orders.     LITHISTIDA    Schmidt. 

Massive,  thick-walled,  siliceous  sponges,  usually  with  complicated  canal-system. 
Skeleton  composed  of  irregulär  tetraxons  or  monaxons  {desmoms)  which  develop 
nodose  or  root-like  hranches  either  at  the  extremities  or  all  along  the  shaft,  and  are 
firmly  united  hy  zygosis.  Symmetrical,  tetraxial,  uniaxial  or  polyaxial  dermal  and 
flesh-spicules  also  present. 

The  Lithistids  are  closely  related  to  the  Tetractinellids,  and  in  the 
opinion  of  many  zoologists,  should  be  embraced  in  the  same  order  with  them. 

The  Lithistids  are  peculiarly  well  adapted  for  preservation,  owing  to  the 
massive  stony  character  of  their  skeletons ;  and  their  remains  occasionally 
form  thick  deposits,  especially  in  the  Jurassic  and  Cretaceous.  Their  outer 
configuration  is  extremely  variable ;  most  commonly  it  is  crateriform, 
cup-shaped,  pyriform,  globular,  bulbous  or  plate-like;  while  the  body  is 
attached  either  by  the  base  or  by  means  of  a  peduncle.  The  canal-system 
varies  greatly  in  different  genera,  but  is  usually  well  developed  and  more  or 
less  complicated.  The  four-rayed  skeletal  elements  are  interlocked  by  means 
of  the  root-like  branching  ends  of  the  rays,  and  the  points  of  intersection 
(nodes)  with  the  ends  of  adjacent  uniaxial  spicules  are  thickened  into  balls. 
The  usually  irregulär  uniaxial  skeletal  elements  are  interlaced  on  all  sides  by 
means  of  root-like  processes.  Dermal  and  flesh-spicules  are  preserved  only 
under  exceptionally  favourable  conditions,  but  are  invariably  present  in 
recent  genera,  and  furnish  valuable  differential  characters.  The  Classification 
of  fossil  Lithistids  is  based  wholly  upon  the  skeletal  elements  and  canal- 
systems.  Five  principal  groups  are  recognised,  whose  subdivision  into 
families  need  not  concern  us  at  present : — Tetracladina,  Euiaxicladina,  Anomo- 
cladina,  Megamorina,  and  Bhizomorina.  Existing  Lithistids  occur  most  abun- 
dantly  at  depths  ranging  between  100  and  400  metres,  but  are  occasionally 
found  as  deep  as  1800  metres. 

Suborder  1.     TETRACLADINA   Zittel. 

Skeletal  elements  composed  of  four  usually  equal  rays,  each  of  which  endoses  an 
axial  canal,  and  has  extremities  ferminating  in  root-like  Strands  or  processes ;  the 

spicules  are  intertwined 
to  form  an  open  mesh- 
work.  Dermal  spicules 
either  grapnel-like  te- 
traxons, frequently  with 
furcate  prongs,  or  dis- 
coidal  with  entire  or 
lohate  margin;  or  they 
are  nail  -  shaped  or 
cylindrical  monaxons. 


Fio.  48, 

Aulocopiurfi  aurantium  Oswald.     Diluvium  ;  Sadowitz,  Silesia.    a,  Example 
in  I/o  natural  size  ;  h,  Skeleton  magnified  60  diaraeters. 


The  skeletal  ele- 
ments  of    the  Tetra- 
cladina   are    usually 
symmetrical    tetrax- 
ons, whose  four  smooth,  more  rarely  tuberculate  or  knotty  rays  intersect  ap- 
proximately  at  an  angle  of  109^°.     They  occur  in  the  Cambrian  and  Silurian, 


»IIDER  TU 


SILICISPONGIAE— LITHISTIDA 


53 


are  very    scarce    in    the  Upper  Jurassic  (Protetraclis),  but  abundant  in   the 
Cretaceous,  Tertiary  and  Eecent  periods. 

A'ulocopium  Oswald  (Fig.   48).     Hemispherical  or  bowl-shaped  with  short 
peduncle ;    inferior   surface  covered  with  a  dense,  wrinkled,  siliceous    skin. 


Fig.  49. 

Callopegma  acaule  Zitt.    Senonian  ;  Ahlten,  Hanover  ;  a,  Specimen  in  3/^  natural  size  ;  h,  Skeleton  magnified 

40/j ;  c,  Portion  of  periphery,  2/j  ;  d,  Same  magnified  40/jj  and  showing  anchors  with  furcate  head-rays. 


Cloaca  central ;  sponge  body  with  numerous  arched  canals  parallel  to  contour 
of  periphery,  and  with  finer  radial  canals  leading  from  exterior  to  cloaca. 
Skeleton  composed  of  irregulär  smooth-rayed  tetraclons  with  root-like  branch- 
ing  extremities,  disposed  in  rows  parallel  to  the  radial  canals.  Occurs  (usually 
replaced  by  calcite)  in  the  Ordovician  of  the  Kussian  Baltic  Sea  Provinces, 


Fig.  50. 

Phymatella  tuberosa  (Quenstedt).  Quadratenkreide 
f'Upper  Senonian);  Linden,  near  Hanover.  a,  Sponge, 
1/2  natural  size  ;  b,  Outer  surface,  1/1 ;  c,  Skeletal  element, 
•'*Vl ;  d,  Spicules  from  stalk  portion,  50/j. 


Fig.  51. 

Siphonia  tulipa  Zitt.  Greensand  ;  Blackdown. 
A,  Longitudinalsection,  natural  size.  B,  Sponge 
with  ])eduncle  and  root,  1/2  natural,  size  (after 
Sowerby). 


Ordovician  of  Illinois,  and  Silurian  of  Gotland.  Also  in  erratic  blocks  on  the 
plains  of  Northern  Germany,  usually  chalcedonised. 

Archaeoscyphia  Hinde.     Cambrian. 

Callopegma  Zittel  (Fig.  49).  Bowl-  or  funnel-shaped,  short-stemmed,  thick- 
walled.   External  surface  perf orated  by  smaller,  internal  by  larger  canal-openings 


54 


COELENTEEATA— PORIFERA 


PHYLÜM  II 


(ostia  and  postica).  Skeleton  composed  of  smooth-rayed  tetraclons,  the  digitate 
extremities  of  which  are  inflated  into  balls.  Dermal  spicules  in  the  form  of 
anchors  and  rods.     Upper  Cretaceous. 

Phymatdla  Zittel  (Fig.  50).     Upper  Cretaceous. 

Polymaraphinina,  SoUasella,  Pseudoplocoscyphia  and  Craterella  Schrammen. 
Upper  Cretaceous. 


Fig.  53. 

Skeletal  element  of  Jerea 
quenstedti  Zittel,  showing 
brancliing  extremities  of 
rays.  Qnadratenkreide;  Lin- 
den, near  Hanover.     ■^^/i. 


Fig.  54, 

PUnthosella  sqiiamosa  Zittel. 
Skeleton  magnilied  80  diameters. 
Senonian  ;  Alilten,  Hanover. 


Fig.  52, 

Jerea  pyriformis  Lamx, 
Greensand ;  Kelheim,  Ba- 
varia,     1/2  natural  size. 

Siphonia  Park. 
(Fig.  51).  Fig-,  pear- 
or  apple-shaped,  with 
a  long  or  short  ped- 
uncle.  Body  with 
deep  cloaca,  into 
which  arched  canals 
running  parallel  with 
the  periphery,  to- 
gether  with  numerous 
fine  radial  canals,  con- 
duct.  Skeleton  com- 
posed of  smooth-rayed,  branching  dichotriders. 
of  monaxons  and  grapnels,     Abundant  in  Middle  and  Upper  Cretaceous, 

Hallirhoa  Lamx.  Like  the  preceding,  but  invariably  short -stemmed. 
Body  pyriform  and  lobate,  owing  to  a  number  of  deep  constrictions. 
Cenomanian. 

Jerea  Lamx.  (Figs,  52,  53).  Body  pyriform,  flask-shaped  or  cylindrical, 
with  truncate  or  depressed  summit,  in  which  a  number  of  tube-like  canals, 
vertical  in  the  central  portion  but  arched  in  the  peripheral,  terminate.  Cross- 
ing the  latter  are  finer  radial  canals,  Skeleton  composed  of  tetraclons  and 
dichotriders.     Common  in  Middle  and  Upper  Cretaceous. 


Rhagadinia  rimosa  Roemer, 
natural  size  ;  b,  Skeleton,  40/j 
Spicule  of  dermal  layer,  4o/j, 


c,  Lobate  disk  from  dermal  layer,  40/^ ; 


Dermal  spicules  in  the  form 


SILICISPONGIAE— LITHISTIDA 


55 


Folyjerea  From. ;  AstroclcuUa,  lliecosiphonia,  Colymmatina  Zitt. ;  Turonia  Mich. ; 
riinthosella  Zitt.  (Fig.  54).  Cretaceous.  Discodermia  Boc. ;  Rhacodiscula  Zitt., 
etc.     Cretaceous  and  Tertiary. 

Rhagadinia  Zittel  (Fig.  55).  Auricular,  plate-  or  bowl-shaped,  short- 
stemmed.  Both  surfaces  traversed  by  irregulär  branching  furrows,  in  which 
the  canalicular  Ostia  are  situated.  Skeletal  elements  four-rayed,  sometimes 
uniformly  or  only  distally  covered  with  tuberculous  knobs,  and  with  digitate 
extremities.  Dermal  spicules  in  the  form  of  six-lobed  disks,  provided  with  a 
short  shaft,  and  minute,  multifid  tetraclons.      Upper  Cretaceous. 

Suborder2.     EUTAXICLADINA   Rauff. 

Skeleton  composed  of  four-rayed  spimles  with  three  equally  developed  simple  or 
hifurcate  rays  which  terminale  distally  in  root-like  fibres  ;  and  one  abbreviate,  inßated 
fourth  ray  (ennomoclon).  Axial  canals  probably  in  all  of  the  rays.  Skeletal  elements 
invariably  arranged  in  either  parallel  or  alternating  rows,  and  unifed  by  zygosis  into 
a  network  with  triangulär  or  irregulär  meshes  ;  spicular  nodes  greatly  inflated. 

Nearly  all  the  genera  are  Silurian ;  a  few  (Mastosia,  Lecanella)  occur  in  the 
Upper  Jurassic. 


^yCS^^ 


Astylospongia  praemorsa  (Goldf.).     In  erratic  block  from  Mecklenburg,    a,  Sponge,  partially  cut  into,  natural 
size;  b,  Skeleton,  12/^ ;  c,  Portion  of  same  highly  magnified. 


Astylospongia  Koem*  (Figs.  56,  b7a).  Spherical,  with  shallow  depression  on 
the  summit ;  base  evenly  rounded,  unattached ;  probably  fastened  by  means 
of  anchoring  fibres.  Large-sized  canals  directed  parallel  to  periphery  in  the 
outer  portion  of  the  body,  vertical  in  central 
portions  ;  besides  these  there  are  numerous  fine 
radial  canals  which  terminate  in  pores  all 
over  the  periphery.  Skeletal  elements  with 
four  smooth  elongated  rays,  one  or  all  of 
which  brauch  dichotomously  just  above  the 
junction  with  the  shorter  arm.  Spicular 
nodes  thickened  into  large  knots.  Ordovician 
of  the  Russian  Baltic  Sea  Provinces,  and 
Silurian  of  Sweden  and   North  America  (not- 

ably  in  Tennessee),  usually  chalcedonised.     Also  in  erratics  in  the  Diluvium 
of  Northern  Germany. 


Fig.  57. 
a,  Detached  skeletal  dement  of  Astylo- 
fponriia,  i'-^o/j ;  b,  Detached  skeletal  ele- 
ment  of  Hindia,  80/^  (after  Kauff). 


56 


COELENTERATA— POEIFEKA 


PHYLUM  II 


Caryospongia,  Carpospongia  RaufF.     Ordovician  and  Silurian  ;  Europe. 

Falaeomanon  Roem.  {Astylomanon  RaufF).  Like  Astylospongia,  but  bowl- 
shaped,  with  shallower  and  wider  cloacal  depression.  Entire .  surf ace  covered 
with  pores.     Silurian  ;  North  America.     P.  cratera  Roem. 

Caryomanon,  Carpomanon  RaufF.     Silurian  ;  North  America. 

Hindia  Duncan  (Fig.  57&).  Body  spherical,  with  perforate  periphery, 
traces  of  attachment  wanting.  All  canals  radiate  from  the  centre  outward. 
Skeletal  elements  composed  of  three  simple  rays  beset  with  prickly  tubercles, 
and  a  reduced  button-like  fourth  arm.  All  spicules  regularly  disposed  in  rows 
parallel  with  the  radial  canals.     Silurian  ;  North  America. 

Neohindia  Schrammen.     Upper  Cretaceous  ;  Germany. 


Suborder  3.     ANOMOCLADINA   Zittel. 

{Didymmorina  RaufF.) 

Skeletal  elements  composed  of  short,  smooth  rays  with  spherically  inflated  ends 
which  give  off  three,  four  or  more  simple  or  digitale  hranches  ;  the  latter  are  united 
hy  zygosis  with  processes  of  adjacent  rays  ;  axial  canals  simple.  Dermal  spicules 
rod-shaped  monaxons.     Upper  Silurian  to  Recent. 

Anomoclonella,  Pycnopegma  RaufF.     Silurian  ;  North  America. 
Cylindrophyma  Zittel  (Fig.  58).      Body  cylindrical,  thick-walled,  attached  ; 
cloaca  wide  and  tube-like,   receiving  numerous  radial  canals,   and  extending 


Cylindrophyma  milleporata  (Goldfuss).    Upper  White  Jura  ;  Hoclisträss.    A,  Two  specimens,  1/2  natural  size. 
B,  Skeleton  magnified  30  diameters.     C,  Detached  siteletal  element  of  Cylindrophyma,  60/^  (after  Rauflf). 


down  as  far  as  the  base.     External  surface  perforated  by  fine  ostia.     Common 
in  Upper  Jurassic. 

Melonella  Zittel.  Skeleton  apple-shaped  or  hemispherical,  with  broad  base, 
or  provided  with  very  short  .peduncle  ;  base  covered  with  wrinkled  siliceous 
skin.  Cloaca  deep,  funnel-shaped.  Coarser  canals  arched,  parallel  with  peri- 
phery ;  finer  incurrent  canals  radially  directed.  Upper  Jurassic.  M.  radiata 
(Quenstedt). 


ORDER  III 


SILICISPONGIAE— LITHISTIDA 


57 


Suborder  4.     MEGAMORINA   Zittel. 

(Rhabdomorina  RaufF.) 

Usually  large-sized,  elongated,  smooth,  bmt,  loosely  interlocking,  irregularhj 
hranching,  or  only  terminally  forked  skeletal  Clements  with  simple  axial  canals  ; 
interspersed  among  which  small,  radiciform,  numerously  hranching  Clements 
{rhizomorins)  are  occasionally  present.  Dermal  spicules  uniaxial  or  grapnel-shapcd. 
Ordovician,  Silurian,  Carboniferous,  Jurassic,  Cretaceous  and  Recent. 

Saccospongia  Rauff.  Silurian.  Megalithista  Zittel.  Upper  Jurassic ; 
Nattheim. 

Dory derma  Zittel  (Fig.  59).  Sponge-body  cylindrical,  simple  or  branching, 
pyriform  or  compressed,  with  a  number  of  larger  canals  running  parallel 
with  the  body 
axis,  and  numer- 
ous  smaller  radial 
canals.  Skeletal 
Clements  large, 
bent  and  divided 
into  two  or  more 
simple  branches. 
Dermal  spicules 
in  the  form  of 
three  -  fluked  an- 
chors.  Upper 
Cretaceous ;  Nor- 
thern Germany, 
England       and  Fig.  59. 

France        AcCOrd-        Doryderma  dichotoma  (Roemer).     Upper  Cretaceous.     a,  Sponge,  natural  size  ;  b, 
TT-    J  Dermal  layer,  2/^;  c,  Bündle  of  skeletal  elements,  lo/j ;    d,  Skeletal  element  and 

ing  to  xlinde,  also    several  dermal  spicules  with  furcate,  anchor-shaped  head-rays,  30/^. 

Carboniferous. 

Gartcrclla  Zittel ;  Astcroderma  Schrammen.     Cretaceous. 

Isorhaphinia  Zittel.  Sub  -  cylindrical,  pedunculate,  with  wide  cloaca 
reaching  nearly  to  the  base.  Skeletal  elements  large,  slightly  bent,  rod- 
shaped,  inflated  at  the  ends,  rarely  dichotomously  branching.  They  are 
associated  in  bundles,  and  so  interlocked  at  their  extremities  as  to  form 
an  open  meshwork.     Cretaceous.     /.  texta  (Roemer). 


Suborder  5.     RHIZOMORINA   Zittel. 


Skeletal  elements  small,  composed  of  four  or  of  three  principal  rays,  or  simple  and 
irregulär,  with  numcrous  projecting  spines  or  tubercles  ;  axial  canal  simple  or  branching. 
Dermal  spicules  monaxons,  tetraxons  or  similar  to  those  of  the  skeleton.  Chiefly 
Jurassic,  Cretaceous  and  Recent. 

Nipterella  Hinde.     Cambrian. 

Cnemidiastrum  Zittel  {Cnemidium,  p.  p.  Goldf.)  (Fig.  60).  Turbinate  or 
bowl-shaped,  with  deep  cloaca.  Walls  thick,  p^rforated  by  numerous  radial 
canals  disposed  in  tiers  one  over  another,  thus  forming  vertical  fissures  which 
often  divide  toward  the  exterior.  Skeletal  elements  irregularly  branching, 
entirely  beset  with  blunt  spiny  processes.     Abundant  in  the  Upper  Jurassic 


58 


COELENTERATA— PORIFEEA 


PHYLUM  II 


Spongiteiikalk  of  South  Germany,  the  skeletons  being  almost  invariably 
replaced  by  calcite.  C.  rimulosum  Goldf.  According  to  Binde  also  present 
in  the  Carboniferous  Limestone  of  Ireland. 


Cnemidiastrum  stellatum  (Goldfuss).  Upper  Jiirassic  Spongiten- 
kalk ;  Hossingen,  Württemberg,  a,  Sponge,  ^/^  natural  size  ;  h, 
Vertical  tangential  section,  showing  radial  canalsin  vertical  clefts  ; 
c,  Skeletal  Clements,  60/j. 


Fig.  61. 
ökeleton     of     Jereica    polystoma 
(Roem.).   Upper  Cretaceous  ;  Ahlten, 
Hanover.     60/. 


Hyalotragos  Zittel.  Bowl-,  plate-  or  funnel-shaped,  with  short  peduncle. 
Depression  in  summit  perforated  by  the  ostia  of  numerous  short  canals.  Ex- 
ternal  surface  finely  perforate,  or  covered  by  a  smooth  or  wrinkled  dermal 
layer.  Skeletal  elements  irregulär,  with  numerous  branches  beset  with  points, 
but  with  few  spines.  Very  abundant  in  Upper  Jurassic  Spongitenkalk.  H. 
(Goldfuss). 


Fig.  62. 

Chenendoporafungiformis  Jjamx.   Senonian  ; 
Chatellerault,  Touraine.     1/3  natural  size. 


.<^  -.  ff  "^  ^    **  iV  \\^  ^  %  y&2 


Verruculina  auriformis  (Roemer).  Quadratenkreide; 
Linden,  near  Hanover.    2/3  natural  size. 


Platychonia  Zittel.  Leaf-  or  ear-shaped,  irregularly  undulating,  covered  on 
both  surfaces  with  fine  pores.  Skeletal  elements  resembling  those  of  Hyalo- 
tragos.    Upper  Jurassic.     P.  vagans  (Quenstedt). 

Jereica  Zittel  (Fig.  61).     Sponge  cylindrical,  turbinate,  pyriform  or  club- 


ORDER  IV  SILICISPONGIAE— HEXACTINELLIDA  59 

shaped,  with  short  peduncle.  Summit  truncated  or  with  shallow  depression, 
perforated  by  the  postica  of  vertical  excurreiit  caiials.  Exterior  perforatod  by 
Ostia  of  the  fiiier  radial  incurrent  canals.  Skeletal  elements  root-like,  berit, 
irregularly  branching,  with  numerous  short  lateral  processes.  Upper 
Cretaceous.     /.  polystoma  (Roemer) ;  /.  punctata  (Goldfuss). 

Chenendopora  Lamx.  (Fig.  62).  Goblet-,  funnel-  or  bowl-shaped,  with 
peduncle.  Cloaca  deep,  perforated  by  postica  of  fine  canals.  Skeletal 
elements  numerously  branched  and  containing  branching  axial  canal.  Upper 
Cretaceous. 

Verriiculina  Zitt.  (Fig.  63).  Foliate-,  funnel-,  ear-  or  bowl-shaped,  short- 
stemmed  or  sessile.  Ostia  on  the  upper  surface  surrounded  by  slight,  collar- 
like  elevations.     Middle  (Gault)  and  Upper  Cretaceous. 

Ämphithelion  Zitt.  Like  the  preceding,  but  with  both  ostia  and  postica 
terminating  in  bosses.     Cretaceous. 

Other  genera :  Scytalia,  Coelocorypha,  Stachyspongia,  Pachinion,  Seliscothon 
Zittel ;  Megarhiza  and  Leiochonia  Schrammen,  etc.,  in  the  ^iddle  and  Upper 
Cretaceous. 

Order  4.     HEXACTINELLIDA    O.  Schmidt. 

(Triaxonia  F.  E.  Schulze.) 

Süiceous  sponges  with  six-rayed  skeletal  elements^  the  rays  being  normally  disposed 
in  three  axes  interseding  at  right  angles,  and  containing  axial  canals  ;  elements  either 
detached  or  fused  together  so  as  fo  form  a  lattice-like  mesh.  Dermal  and  flesh  spicules 
exceedingly  variable  in  form,  but  invariably  six-rayed. 

Next  to  the  Lithistida,  the  Hexactinellida  are  the  most  abundant  of  the  fossil 
siliceous  sponges.  They  are  extraordinarily  variable  in  form,  and  are  often 
anchored  by  a  tuft  or  "rope"  of  long,  slender,  vitreous  fibres,  or  are  attached 
directly  by  the  base.  The  walls  are  thin  as  a  rule,  and  enclose  usually  a  wide 
cloaca ;  the  canal-system  is  consequently  much  simpler  than  in  the  Lithistida., 
being  made  up  merely  of  short  tubes  which  penetrate  the  walls  more  or  less 
deeply  on  both  sides,  and  generally  end  blindly.  Sometimes  the  sponge  is 
entirely  composed  of  thin-walled  tubes  which  twine  about  one  another  irregu- 
larly and  produce  a  System  of  lacunar  interstices  (intercanals)  of  greater  or 
less  size. 

The  skeletal  elements  proper  are  distinguished  by  their  considerably  larger 
size  and  simple  form  from  the  usually  minute,  astonishingly  variable  and 
delicate  flesh-spicules ;  the  latter,  unfortunately,  are  seldom  preserved  in  the 
fossil  State.  The  skeletal  elements  occur  detached  in  the  soft  parts  in  the 
Lyssacina  group,  or  are  partially  or  irregularly  cemented  together ;  in  the 
Dictyonina  group,  on  the  other  band,  they  are  regularly  united  in  such  manner 
that  the  rays  of  proximate  elements  are  all  closely  applied  against  one  another, 
and  are  surrounded  by  a  continuous  siliceous  envelope.  In  this  way  a  more 
or  less  symmetrical  lattice-work  with  cubical  meshes  is  produced,  in  which, 
however,  the  fusion  of  juxtaposed  elements  is  indicated  in  that  each  ray  con- 
tains  two  distinct  axial  canals.  The  junction  of  the  rays  at  the  central  node 
of  each  element  is  usually  inflated,  but  is  sometimes  sculptured  in  such  manner 
as  to  enclose  a  hollow  octahedron  (lantern  nodes,  lychnisks).  The  exterior  of 
the  skeleton  is  often  covered  by  a  dermal  layer  composed  of  irregulär  hexactins. 


60  COELENTERATA— PORIFERA  phylum  ii 

in  which  the  externally  directed  ray  has  become  atrophied  ;  or  a  dense  siliceous 
envelope  is  secreted,  in  which  stellate  hexactins  with  reduced  outwardly 
and  inwardly  directed  rays  (stauractins)  are  embedded  in  greater  or  lesser 
profusion. 

The  Hexactinellida  of  the  present  day  are  distributed  chiefly  over  the  greater 
depths  of  the  ocean  beyond  the  hundred-fathom  line  (200  to  3000  fathoms). 
They  occur  fossil  principally  in  deep-sea  deposits,  and  make  their  first  appear- 
ance  in  the  Cambrian ;  their  period  of  greatest  development  coincides  with 
Jurassic  and  Cretaceous  time. 

Suborder  1.     LYSSACINA   Zittel.   ^ 

Skeletal  elements  either  entirely  detached,  or  only  partially  and  in  an  irregulär 
fashion  cemented  together.     Root-tufl  offen  present. 

The  Lyssacina  are  poorly  adapted  for  preservation  in  the  fossil  state,  since 
the  skeletal  elements  are  but  rarely  cemented  together  to  form  a  connected 
framework,  and  the  flesh-sjpicules  are  invariably  destroyed.  Notwithstanding, 
complete  sponges  composed  of  large-sized  detached  hexactins  have  been  found 
in  Paleozoic  formations,  and  also  in  the  Upper  Jurassic  of  Streitberg;  and, 
indeed,  the  oldest  sponges  that  can  be  determined  with  certainty  all  belong  to 
the  Lyssacina. 

Family  1.     Protospongidae    Hinde. 

Thin-walled,  sack-,  tuhe-like  or  spherical  sponges,  with  walls  composed  of  a  Single 
layer  of  cruciform  tetraxial  spicules  (stauractins),  arranged  so  as  to  form  quadrate 
and  suhquadrate  meshes.  Elements  non-fasciculate.  The  reticulation  formed  by  the 
larger  elements  is  divided  into  secondary  Squares  hy  smaller  spicules,  so  that  the  mesh- 
work  is  constituted  of  several  series  of  Squares.     Cambrian  and  Ordovician. 

To  this  family  belong  the  genera  Protospongia  Salter,  and  Fhormosella  Hinde. 

Family  2.     Dictyospongidae    Hall. 

Usually  large,  funnel-shaped,  cylindrical  or  prismatic  sponges,  whose  thin  walls 
are  frequently  diver sified  by  ridges  and  prominences.  Skeletal  framework  very  regulär, 
and  composed  of  larger  and  smaller  quadrate  meshes  situated  one  within  the  other. 
Framework  formed  by  bundles  of  slender  spicules.  Chiefly  in  Devonian  (Chemung) 
and  Lower  Carboniferous  (Keokuk)  of  North  America,  and  Devonian  of  Europe. 

Subfamily  1.     Dictyospongiinae    Hall  and  Clarke. 


Hall  and  Clarke.  Smooth,  obconical  or  subcylindrical 
sponges  devoid  of  nodes,  ridges  or  other  ornamentation ;  base  furnished  with 
a  tuft  of  long,  straight,  anchoring  spicules.     Silurian  and  Devonian. 

Hydnoceras  Conrad  (Fig.  64).  Obconical  more  or  less  rapidly  expanding 
sponges  with  eight  prism-faces  and  nodes  in  horizontal  and  vertical  rows.  Base 
with  short  tuft  of  anchoring  spicules.     Devonian  and  Carboniferous. 

Lysactinella  Grirty ;  Hydriodictya,  Prismodictya,  Gongylospongia,  Botryodictya, 
Helicodictya,  Rhabdosispongia,  Ceratodictya,  Clathrospongia,  Lebedicfya  Hall  and 
Clarke.     Chemung  Group  ;  New  York. 


ORDER  IV  SILICISPONGIAE— HEXACTINELLIDA  61 


Subfamily  2,     Thysanodictyinae    Hall  and  Clarke. 

Thysanodidya  Hall  and  Clarke.  Subcylindrical  or  tapering  Dictyosponges 
with  prominent  projecting,  rectangularly  reticulating  spicular  bands  or  lamellae 
forming  series  of  fenestrated  quadrules  upon  the  surface.  Base  with  basal 
disk  or  broad  obcone.     Devonian. 

Phragmodicfya  Hall ;  Arystidida,  Adoeodiäya,  Griphodidya  Hall  and  Clarke. 
Upper  Devonian  and  Lower  Carboniferous. 

Subfamily  3.     Calathospongiinae    Hall  and  Clarke. 

Calathospongia  Hall  and  Clarke.  Stout  subcylindrical  cups  with  truncated 
bases,  probably  attached  by  the  basal  margins ;  contracted  mesially  and  more 
or  less  expanded  at  the  aperture.  Surface  without 
nodes.     Carboniferous. 

Clepsydrospongia  Hall  and  Clarke.  Thamnodidya, 
Cleodidya  Hall. 

Subfamily  4.   Physospongiinae    Hall  and  Clarke. 

Physospongia  Hall.  Keokuk  group.  Roemeri- 
spongia  Hall  and  Clarke.     Eifel  Devonian. 

Subfamily  5.     Hyphantaeniinae    Hall  and  Clarke. 

Hyphantaenia  (Uphantaenia)  Vanuxem.  Large, 
circular  and  shallow  saucer-shaped  cups,  composed 
of  two  series  of  intersecting  spicular  straps,  one 
radiating,  the  other  concentric.  Chemung  Group; 
New  York. 

Fio.  64. 

Subfamily  6.     Hallodtctyinae  Hall  and  Clarke.  cÄ"'''Siemung'G^^^^ 

.  ^  N.Y.     Sponge  showing  foiir  rovv.s 

Hallodidya  Hall  and  Clarke.     Admodidya,  Crypto-    of  streng  nodes  and  rineiy  reticu- 

T  .        -r-r   11         r^^  /-^  "NT         ^T      ^  lated  surface,  V?  (after  Hall  and 

didya  Hall.     Chemung  Group ;  New  York.  ciarke). 

Subfamily  7.     Aglithodictyinae    Hall  and  Clarke. 
Aglithodidya  Hall  and  Clarke.     Chemung  Group ;  New  York. 

Family  3.     Plectospongidae    RaufF. 

Thin-walled  tubes  with  skeleton  composed  of  a  regulär  frameworh  made  up  of  an 
ascending  and  approximately  ring-like  series  of  spicules  ;  the  latter  form  redangular 
to  Quadrate,  but  not  very  symmetrical  meshes.  Spicular  rays  fasciculate.  Ordovician 
and  Silurian. 

Cyathophycus  Walcott ;  Falaeosaccus,  Acanthodidya  Hinde.  Ordovician. 
Pledoderma  Hinde.     Silurian. 


62 


COELENTEEATA— PORIFEKA 


PHYLUM  II 


Genera  incertae  sedis. 

Pattersonia  Miller  (Strohilospongia  Beecher).  In  form  of  large  botryoidal 
clumps.  Brachiospongia  Marsh.  Vase-like  sponges  with  broad  inferior  margin 
prolonged  into  a  number  of  hollow  arms.  Ordovician  of  North  America. 
These,  together  with  Ämphispongia  Salter,  and  Astroconia  Sollas,  from  the 
Silurian  of  England,  represent  extinct  families  of  the  Lyssacina. 

Pyritonema  M'Coy  {Acestra  Roem.)  Fascicles  of  long,  stout  spicules, 
supposed  to  be  root-tufts.     Silurian. 

Hyalostelia  Zitt.  (Acanthospongia  Young).  Skeletal  elements  relatively  large, 
in  the  form  of  regulär  hexactins  and  stellate  bodies  with  reduced  vertical  ray, 
and  with  infiated  nodes. 
Root-tuft  composed  of  elon- 
gated,  slightly  bent  fibres, 
sometimes  terminating  in 
four  recurved  rays.  Cam- 
brian to  Lower  Carboni- 
ferous ;  Great  Britain. 

Holasterella  Carter; 
Spiraäinella  (Fig.  65),  and 
Acanthactinella    Hinde,    are  pj^^  qq^ 

allied    genera   occurring    in      ThoUastereiia    qracius 
the     Lower     Carboniferous    ?Sone -^S^f  a7 

ot  Great  Britain.  f'">-    Dermallayerwith 

._-r.     ,     ,-^.  lused    stellate    spicules, 

ThoUastereiia  Hmde  (r  ig.     5/1  (after  Hinde). 


Fig.  65. 

Spiractinella  wrightii  (Carter). 
Carboniferous  Limestone ;  Sligo, 
Ireland.  A,  Normal  hexactin.  B, 
Hexactin  with  forked  rays,  0/1 
(after  Hinde). 


Fig.  67 


Asteractinella  expansa  Hinde. 
Carboniferous  Limestone  ; 
Dalry,  Ayrshire.  Skeletal 
Clement,  5/^  (after  Hinde). 


Astraeospongia  menis(ni,s  Roemer. 
Silurian ;  Tennessee.  A,  Sponge,  in 
proüle,  2/3  natural  size.  B,  Upper 
surface  of  same. 


66),  from  the  Carboniferous,  has  thin  walls  composed  of  a  layer  of  robust, 
irregularly  amalgamated  hexactins.  As  a  rule,  two  of  the  rays  lying  in  the 
same  plane  divide  dichotomously  from  the  nodes  outward,  so  as  to  produce 
a  six-armed  instead  of  a  four-armed  cross.  In  Asteractinella  Hinde  (Fig.  67), 
all  of  the  rays  lying  in  the  same  plane  divide  in  two  or  more  branches,  thus 
giving  rise  to  many-rayed,  extremely  diverse,  stellate  and  corolla-like  bodies. 
Carboniferous ;  Ayrshire. 

Astraeospongia  Eoem.  (Fig.  68).  Thick-walled,  depressed,  bowl-shaped, 
Upper  surface  concave,  lower  convex,  without  traces  of  attachment.  Skeleton 
composed  of  relatively  large,  homogeneous,  uncemented  cruciform  spicules ; 
six  of  the  rays  are  disposed  in  the  same  plane,  while  the  two  rays  projected 
at  right  angles  to  these  are  reduced  to  short,  button-like  prominences.  Common 
in  Silurian  of  Tennessee  and  Devonian  of  the  Eifel. 


ORDER  IV 


SILICISPONGIAE— HEXACTINELLIDA 


63 


According  to  Hiiide,  Tholiasterella  and  AsteracMnella  constitute  a  distinct 
Order  (Heteraäinellidae),  and  AstraeosjJongia  is  made  the  type  of  the  order 
Octadinellidae.  These  two  groups  may  perhaps  best  be  regarded  as  aberrant 
Hexactinellids,  in  which  supernumerary  rays  are  produced  by  branching. 

Suborder  2.     DICTYONINA   Zittel. 

Skeletal  spicules  cemented  to  form,  a  continuous  framework  in  such  a  way  that 
every    arm    of     a  „ 

hexaäin  is  applied 
to  the  correspondiiig 
arm  of  an  adjacent 
spicule,  and  hoth 
rays  hecome  en- 
veloped  in  a  common 
silieeous  covering. 
Root-tuft  absent. 

The  Dictyonina 
are  probably  de- 
scendants  of  the 
Lyssacina  (possi- 
bly  from  Froto- 
spongia-  and  Dictyo- 
phyton-Mke  forms). 
They  appear  first 
in  the  Trias,  and 
play  a  prominent 

role  as  rock-builders  in  the  Jurassic  and  Cretaceous.     Their  lattice-like  skeletons 

are  frequently  replaced  by  calcite,  or  are  dissolved  away  and  merely  indicated 

a   '  .  h  by  cavities.     The  more  important  fossil 

forms  are   divided   into   the  foUowing 
families. 

Family  1.    Oraticularidae  Raiiff.    {Eure- 
tidae  p.  p.,  Zittel  non  Schulze.) 

Cup-shaped,  cylindrical,  hranching  or 
flatternd  sponges.  Spicular  nodes  solid. 
External  surface  without  distinct  dermal 
layer,  hut  protected  by  a  thickening  of  the 
outer  skeletal  layer,  and  occasionally  covered 
with  a  delicate  web  of  cemented  spicules. 
Canals  simple,  blindly  terminating  in  the 
skeleton.     Jurassic. 

Tremadictyon  Zitt.  (Fig.  69).  Cup-, 
plate-shaped  or  cylindrical,  with  wide 
cloaca.  Canal-openings  on  both  sides  in  alternating  rows.  Base  nodular; 
exterior  veiled  over  with  delicate  net-work  of  amalgamated  hexactins,  extend- 
ing  even  across  canal  pores.  Skeletal  framework  with  more  or  less  irregulär 
cubical  meshes.     Very  common  in  Upper  Jurassic. 

Craticularia   Zitt.    (Fig.    70).     Funnel-shaped,    cylindrical    or    flattened ; 


Fig.  69. 


Tremadictyon  reticulatum  (Goldf.).  Upper  Jurassic ;  ötreitberg,  Franconia.  a, 
Sponge,  2/5  natural  size  ;  b,  Enlarged  portion  of  outer  surface  without  dermal  layer  ; 
c,  Portion  with  well-preserved  dermal  layer,  3/j  ;  d,  Skeleton,  12/^. 


Fig.  70. 


Upper  Jurassic ; 


Craticularia  jmradoxa  (Münster). 
Muggendorf,  Franconia.     a,  Sponge,  1/3  natural  size  ; 
b,  Latticed  skeleton,  12/1 ;  c,  Thickened  dermal  layer, 


64 


COELENTERATA— POEIFERA 


PHYLÜM  II 


simple  or  branching.  Canal  -  openings  on  both  surfaces  either  round  or 
elliptical,  and  regularly  distributed  in  vertical  and  horizontal  rows.  Canals 
short,  ending  blindly.     Jurassic,  Cretaceous  and  Miocene. 

Sporadopyle  Zitt.  Cup-  to  funnel-shaped  or  conical,  occasionally  branching. 
Canal -openings  on  the  outer  surface  irregularly  distributed,  or  arranged  in 
quincunx ;  on  the  cloacal  surface  in  vertical  rows.  Upper  Jurassic.  S.  ohliqua 
(Goldfuss). 

Sphenaulax  Zittel,  Ferrucocoelia  Etallon.  Jurassic.  Polyosepia  Schrammen. 
Upper  Cretaceous. 

Family  2.     Ooscinoporidae   Zittel. 

Calycoid,  beaJcer-like,  lobate,  branching  or  stellately  convoluted  sponges,  with  thin 
walls  perforated  on  both  sides  by  numerous  canal-openings  arranged  in  alternating 

rows;  canals  shori 


blindly.  Framework  com- 
pact, with  fine  meshes  ; 
dermal  layer  replaced  by 
thicJcening  of  the  outermost 
skeletal  layer.  Spicular 
nodes  solid,  more  rarely 
perforate.     Cretaceous. 

Leptophragma  Zitt. 
Beaker  -  shaped,  with 
root  -  like  attachment. 
Walls  thin,  covered  on 
both  sides  with  small 
canal-openings  arranged 
in  alternating  rows. 
Mesh-work  very  closely 
woven,  spicular  nodes 
solid.  Middle  and 
Upper  Cretaceous. 

Pleurostoma'Roem.;  Guettardia  Mich. ;  Balantionella  Bchrsimmen.    Cretaceous. 

Coscinopora  Goldf.  (Fig.  71).     Beaker-like,  with   branching  roots.     Ostia 

small,    round   and    in  alternating    rows.       Skeletal    elements    in    part  with 

perforated  intersection  nodes.     Eoot  consisting  of  long  siliceous  fibres.     Dermal 

layer  formed  by  the  thickening  and  fusion  of  outermost  hexactins.     Cretaceous. 


Fig.  71. 


Coscinopora  infundibuliformis  Goldf.  Upper  Cretaceous  ;  Coesfeld,  West- 
phalia.  a,  Complete  speciinen,  1/2  natural  size ;  b,  Outer  surface,  natural 
size  ;  c,  Same,  3/^ ;  d,  Skeleton  of  cup,  12/j ;  e,  Skeleton  of  root,  i'-^/i. 


Fainily  3.     Staurodermidae    Zittel. 

Turbinate,  funnel-shaped  or  cylindrical,  more  rarely  branching  or  in  clumps. 
Ostia  and  postica  irregularly  distributed,  or  in  alternating  rows.  Skeletal  framework 
more  or  less  regidar ;  intersection  nodes  thick  or  octahedrally  excavated.  The 
outer  or  both  surfaces  of  the  wall  provided  with  large,  stellate  spicules  (stauractins), 
which  differ  from  those  of  the  rest  of  the  skeleton,  and  are  either  but  loosely  cemented 
together  or  are  embedded  in  a  continuous  siliceous  skin.     Jurassic  and  Cretaceous. 

Cypellia  Zitt.  (Fig.  72).  Top-shaped,  bow-shaped  or  branching,  without 
root.  Canals  irregularly  distributed,  crooked,  and  branched.  Lattice 
skeleton  with  irregulär  meshes,  intersection  nodes  perforated.     Dermal  layer 


011J)ER  IV 


SILICISPONGIAE— HEXACTINELLIDA 


65 


composed  of  large,  four-rayed  stauractins  embedded  in  a  thin,  continuous  or 
perforated  skin.     Very  common  in  Upper  Jurassic  Spongitenkalk. 

Stauroderma  Zitt.  Funnel-shaped  or  plate-like,  with  broad  and  shallow 
cloaca,  into  which  the  large,  round  postica  of  short  canals  open.  Inner  and 
outer  surfaces  provided  with  dermal  layer,  in  which  stellate  spicules  are 
embedded  with  reduced  externally  and  internally  directed  rays.  Upper 
Jurassic. 

Casearia  Quenst.  Cylindrical,  with  numerous  annular  constrictions. 
Cloaca  deep,  tubiform ;  dermal  layer  relatively  thick,  and  made  up  of 
cemented  stellate  spicules.     Upper  Jurassic.     C.  articulata  (Goldfuss). 

Porospongia  d'Orb.  (Fig.  73).  Compressed  and  expanded,  more  rarely 
bulbous  or  cylindrical.  Superior  surface  pitted  with  large  exhalent  apertures 
of  short,  blindly  terminating  cloacae,  and  covered  over  with  a  dense  or  finely 
perforate  siliceous  skin,  in  which  cruciform  spicules  and  regulär  hexactins  are 


Cypeläa  rugosa  (Goldfuss).  Upper  Jurassic  ;  Streit- 
berg, Franconia.  a,  Spoiige,  1/2  natural  size ;  b,  c, 
Dermal  layer,  i^/j. 


Porospongia  impressa  (Goldfuss).  Upper  Jurassic : 
Muggendorf,  Franconia.  a,  Fragment  in  natural  size 
b,  Dermal  layer,  6/^ ;  c,  Skeleton,  12/^. 


embedded.     Lattice  skeleton  with  cubical  meshes ;  intersection  nodes  imper- 
forate.     Upper  Jurassic. 


Family  4.     Ventriculitidae    Toulmin  Smith. 

^Fall  intricately  convoluted ;  folds  radially  disposed,  generally  vertical  in  direc- 
tion.  Radial  canals  ending  hlindly.  Longitudinal  furrows  developed  along  folds  of 
the  wall,  and  either  open,  or  partially  covered  over  with  a  dermal  layer,  which  is  usually 
formed  hy  thickening  of  the  outer  skeletal  layer.  Skeletal  frameioork  with  octahedrally 
perforated  nodes.  Boots  consisting  of  elongated  siliceous  fibres  united  hy  transverse 
hridges  and  without  axial  canals.     Jurassic  and  Cretaceous. 

Pachyteichisma  Zittel  (Fig.  74).  Turbinate  or  bowl-shaped,  with  very  thick, 
convoluted  wall.  Folds  separated  on  outer  surface  by  deeply  incised  furrows, 
on  inner  surface  by  shallow  furrows.  Framework  extremely  regulär.  Root 
and  dermal  layer  absent.     Upper  Jurassic. 

Ventriculites  Mantell  (Fig.  75).  Bowl-,  plate-,  beaker-,  funnel-shaped,  or 
cylindrical,  with  wide  cloaca.  Wall  thin,  convoluted  ;  folds  separated  on  both 
sides  by  closely  crowded  longitudinal  furrows.  Lattice-work  of  skeleton  more 
VOL.  I  F 


66 


COELENTERATA— PORIFERA 


PHYLUM  II 


or  less  regulär;  outer  layer  thickened ;  roots  present.     Common  in  Middle 
and  Upper  Cretaceous. 


Fia.  74. 

PachyteicMsma  carteri  Zittel.  Upper 
Jurassic ;  Hohenpölz,  Franconia.  a, 
Sponge,  1/2  natural  size  ;  b,  Skeleton,  12/j. 


Fig.  75. 

VentricuUtes  striatvs  Smith.  Qnadratenkreide  ;  Linden, 
near  Hanover.  a,  Sponge,  1/2  natural  size  ;  b,  Transverse 
section,  1/1 ;  c,  Skeleton,  12/j. 


Fio.  76. 

CoeloptycTinim  agaricoides  Goldf.     Upper  Cretaceous  ;  Vordorf,  near  Brunswick.    A,  Top  view.    li,  Profile. 

C,  Under  surface,  2/3  natural  size.    D,  Skeleton,  60/j, 

Schizorhabdus,   Bhizopoterion,   PolyllasUdium  Zittel ;    Sporadoscinia   Pomel ; 


1 


ER  IV 


SILICISPONGIAE— HEXACTINELLIDA 


67 


Lepidospongia  Roemer;  Leiostracosia,  Plectodermatium,  Microblastidium  Schram- 
men, etc.     Cretaceous. 


Family  5,     Ooeloptychidae   ZitteL 

Umbel-  or  mushroom-shaped,  with  stalk.  Wall  thin,  deeply  folded.  Convolutions 
radialhj  arranged,  hecoming  furcate  toward  periphery  of  umbel,  and  exposed  on  lower 
surface.     Marginal  and  ^^ 

Upper  surface  enveloped 
with  porous  dermal  layer 
entirely  covering  thefolds. 
Ostia  only  on  under  side 
of  umbel,  situated  on 
backsof thefolds.  Frame- 
work very  regulär ;  inter- 
sedion  nodes  odahedral, 
perforated  ;  rays  ofhex- 
actins  provided  with 
slender,  thorny  processes. 

Coeloptychium 
Goldf.    (Fig.    76),   oc- 

curring  in  the  Upper  Cretaceous  of  Northern  Germany,  England,  and  Southern 
Russia,  is  the  solitary  genus. 


Fig.  77. 
Flocoscyphia  pertusa  Gein.  I  Greensand  (Cenomanian) 
«.'Fragment  in\natural  size  ;l&,  Dermal  layer,  live  times  enlarged 
of  interior,  12/^1;  d,  Outward  portion  of  skeleton,  12/j 


Banowitz,  Hungary. 
Skeleton 


Family  6.     Maeandrospongidae   ZitteL 

Sponge  body  consisting  of  thin-walled,   intricately  labyrinthine,   and  partially 
amalgamated  tubes  or  foliae,  which  form  tuberous,  pyriform,  beaker-shaped,  or  bush- 

ß  like     branching    Stocks. 

Between  the  tubes  are 
cavities  and  interstices 
of  considerable  size, 
which  constitute  the  so- 
called  intercanalicular 
System.  Four  canals 
faintly  developed.  Der- 
mal layer  absent,  or  re- 
presented  by  a  continuous 
silicious  superficial  skin. 
Abundant  in  the  Cre- 
taceous, and  also  re- 
presented  by  numerous 
recent  genera. 

Flocoscyphia  Reuss 
(Fig.  77).     Clump-like 
or  bulbous  Stocks  con- 
sisting of  labyrinthic, 
anastomosing  tubes  or  foliae.     Walls  of  tubes  thin,  perforated  by  numerous 
small  Ostia.     Latticed  skeleton,  intersection  nodes  solid  or  perforate.     Cre- 
taceous. 

Becksia  Schlüter  (Fig.    78).     The  thin  walls  of  the  shallow,  beaker-like 


Fig.  78. 

Becksia  sokdandi  Schlüt.  Quadratenkreide ;  Coesfeld,  Westphalia.  A, 
Sponge  body,  1/2  natural  size  ;  0,  Ostia  of  radial  canals  ;  /,  Hollow,  root-like 
processes  of  wall.     B,  Skeleton,  50/j. 


COELENTEKATA— POEIFEKA 


PHYLUM  II 


sponge  are  composed  of  vertical  tubes  having  a  radial  disposition  and  fused 
with  one  another  along  the  sides.     Between  the  tubes  are  large  interstices ; 
near  the  base  the  tubes  develop  hollow,  spinous  processes.    Lattice  skeleton  very  i 
regulär,  exactly  similar  to  Coeloptijchium.     Upper  Cretaceous ;  Westphalia. 

Tremaholites    Zitt. ;    Etheridgia  Täte ;    Zittelisjjongia   SinzofF,   etc.      Upper 
Cretaceous. 

Camerospongia    d'Orb.    (Fig.    79).     Globular,    sub-globular,    or    pyriform. 


FlG 


Camerospongia  fungiformis 
(Goldfuss).  Plänerkalk ;  Oppeln, 
Silesia.    Natural  size. 


Fig.  80. 

Cystispongia  hursa  Quenst.  Cuvieri-Pläner  (Turonian);  Salz- 
gitter,  Hanover.  a,  Sponge,  natiiral  size ;  h,  Dermal  layer  with 
underlying  skeletal  framework  ;  c,  Skeleton,  12/^. 


Upper  half  of  the  body  enveloped  by  smooth  siliceous  skin,  and  with  large 
circular  depression  on  the  summit ;  lower  half  marked  b}^  undulating  ridges 
and  furrows,  and  passing  gradually  into  a  stem.  Interior  of  sponge  body 
consists  of  thin-walled,  labyrinthous  tubes.     Upper  Cretaceous. 

Cystispongia  Eoem.  (Fig.  80).  Like  the  preceding,  but  with  dense  siliceous 
skin  punctured  by  large,  irregularly  shaped  apertures,  uniforraly  enveloping 
the  whole  sponge  body.  Body  composed  entirely  of  tubes.  Cretaceous  and 
still  living. 


Subclass  4.     CALCISPONGIAE.     Calcareous  Sponges. 
Skeleton  composed  of  calcareous  spicules  of  three-rayed,  four-rayed,  or  uniaxial 

The  external  form  of  the  Calcisponges  is  quite  as  variable  as  that  of  the 
siliceous  sponges,  and  reminds  one  particularly  of  the  Lithistida.  Like  the 
Lithistids,  too,  the  thick-walled  Leucones  and  Pharetrones  have  a  canal-system 
consisting  of  a  central  cavity  into  which  radial  excurrent  canals  conduct ; 
while  the  numerous  tributaries  of  the  latter  end  in  ciliated  Chambers  which 
are  fed  by  fine  incurrent  canals.  In  the  Sycones  the  wall  is  perforated  by 
simple  radial  tubes,  but  in  the  thin-walled  Ascones  it  is  pierced  by  mere  holes. 

The  calcareous  skeletal  Clements  lie  free  in  the  soft  parts,  sometimes 
forming  but  a  single  layer  disposed  in  the  same  plane  {Ascones) ;  sometimes 
their  disposition  is  more  or  less  distinctly  radial,  following  the  canal  courses 
(Sycones) ;  sometimes  they  are  irregularly  crowded  together  (Leucones) ;  and 


ORDER  I 


CALCISPONGIAE— PHARETRONES 


69 


^^^^^^^^ 


sometimes  they  are  closely  opposed  iii  the  form  of  solid  anastomosing  fibres 
(Pharetrones).  Regulär  triaxial  spicules  are  of  the  most  common  occurrence, 
next  monaxial  spicules,  sharpened  on  both  sides,  and 
more  rarely  four-rayed  spicules. 

Ovving  to  the  ready  solubility  of  the  skeletal  Clements 
in  calcareous  sponges,  they  are  usually  but  poorly  pre- 
served  in  the  fossil  state,  and  are  ill-adapted  for  micro- 
scopical  investigation.     The  three-rayed  and  rod-shaped 
spicules  which  are  united  in  fibres  are  seldom  distinctly 
recognisable  as  such,  since,  as  a  rule,  they  are  either 
wholly  or    partially  dissolved,   and  are  converted    into 
homogeneous  or  cry stalline  fibres  of  calcite  (Fig.  84) ;  in 
these  minute   threads  of  calcite  may  be  seen  radiating 
in  all  directions  from  numerous  centres  of  crystallisation.     Sometimes  such 
calcareous  skeletons  afterwards  become  silicified.     It  is  clear,  therefore,  that 
the  present  chemical  composition  of  a  fossil  sponge  furnishes  us  no  clue  in 
regard  to  its  original  character,  since  during  the   process   of  fossilisation  a 


Triaxial  skeletal  elements 
of  a  Recent  Ascon,  ^/i. 


Fio.  82, 


Fibres  of  a  Pharetrone,  composed  of  three-  Solid  fibres  of  fossil  calcar-  Fibres  of  fossil  calcareous 
rayed  spicules.  Feronidella  cylindrica  (Gold-  eous  sponge  with  partially  sponge  altered  by  crystallisa- 
fuss).     Upper  Jurassic,  40/j.  preserved  spicules,  ^o/^.  tion,  40/^. 

siliceous  skeleton  may  become  converted  into  a  calcareous,  and  a  calcareous 
into  a  siliceous. 

Of  the  four  Orders  of  calcareous  sponges — Pharetrones,  Sycones,  Ascones,  and 
Leucones — only  the  first  two  are  of  practical  importance  to  the  paleontologist, 
traces  of  the  others  being  either  wanting  or  extremely  fragmentary. 


Order  1.     PHARETRONES    Zittel. 

^rall  thick  ;  canal  System  like  that  of  the  Lithistida,  though  sometimes  indistinct 
and  apparently  absent.  Spicules  arranged  in  solid  anastomosing  fibres  ;  a  smooth  or 
corrugated  dermal  layer  frequently  present.  Devonian  to  Cretaceous  ;  unknown  in 
Tertiary  and  Recent. 

Eudea  Lamx.  Cylindrical  or  club-shaped,  usually  simple,  rarely  branching. 
Cloaca  narrow,  tubiform,  extending  to  the  base,  and  terminating  above  in  a 
round  osculum.  Dermal  layer  smooth,  perforated  by  ostia  of  short  canals. 
Triassic  and  Jurassic.     E,  clavata  Lamx. 

Peronidella  Zitt.  (Peronella  Zitt.  non  Gray ;  Siphonocoelia,  Polycoelia  From.), 
(Figs.  85,  86).  Thick  -  walled,  cylindrical,  simple  or  branching.  Cloaca 
tubiform,  extending  to  the  base ;  base  sometimes  covered  by  a  dense  dermal 
layer.     The  rest  of  the  exterior  finely  perforate.      A  distinct  canal-system 


70 


COELENTERATA— PORIFERA 


PHYLÜM  II 


absent.  The  coarse,  anastomosing  skeletal  fibres  composed  of  closely  packed 
three-rayed  and  one-rayed  spicules.  Sparse  in  Devonian  (P.  constricta  Sandb.) ; 
common  in  Trias,  Jurassic,  and  Cretaceous. 


Fig.  85. 

Peronidella  cylin- 
drica  (Münst.). 
Upper  Jura. ;  Miig- 
gendorf.     x  1/2. 


Fio.  86. 

Peronidella  diimosa  (From.). 
Hils  ;  Berklingen,  Bruns- 
wick.    Natural  size. 


Fig.  87. 

Corynella  quenstedti  Zitt.  Coral-Rag;  Natt- 
heim.  0,  Sponge,  natural  size ;  b,  Skeletal 
fibres,  4/1. 


Fig.  88. 

Eusiphonella  bronni 
(Münst.).  Coral-Rag ; 
Nattheim.  Natural 
size. 


Oculospongia  tu- 
hulifera  (Goldf.). 
Kreidetuflf;  Mae- 
stricht. 
size. 


Fig.  90. 


Eusiphonella  Zitt.  (Fig.  88).     Similar  to  preceding,  but  thin-walled,  with 

broad  cloaca  extending  to 
the  base,  into  which  con- 
duct  radial  canals  ar- 
ranged  in  vertical  rows. 
External  surface  per- 
forate.  Upper  Jurassic. 
Corynella  Zitt.  (Fig. 
87).  Knob-like,  cylindri- 
cal,  or  top-shaped,  thick- 
walled,    simple,    or    com- 

Natural     (Q^eSr  €0?^^     P^'^*®'  ^^^^^^    ^^^^^^  " 

Nattheim.  Natural  size.  shaped,  shallow,  terminat- 
ing  below  ^in  a  series  of 
vertical  branching  tubes  ;  exhalent  aperture  often  surrounded  with  radially 
diverging  furrows.  Ostia 
conducting  into  numer- 
ously  branching  radial 
canals,  which  unite  again 
in  larger  excurrent  canals, 
and  open  into  the  cloaca. 
Common  in  Trias,  Jur- 
assic, and  Cretaceous. 

Stellispongia  d'Orb. 
(Fig.  90).  Usually  com- 
posite  Stocks  made  up  of 
hemispherical,     or    short 

pear-shaped  perSOnS,  with    Upper  surface,  natural  size. 

base   enveloped    by  com- 
pact dermal  layer.     Summit  dome-shaped,  with  shallow  cloaca  surrounded  by 
radial  furrows ;  radial  and  vertical  canals  terminating  along  sides  and  basis  of 


Hils 


Fig.  91. 

Elasmostoma  acntimargo  Roem. 
Berklingen,     Brunswick. 


Fig.  92. 


RhapMdo  nema  farringdonense 

(Sharpe).  Lower         Cretaceous 

(Aptian) ;     Farringdon,    Berkshire. 
2/0  natural  size. 


ORDER  II 


CALCISPONGIAE— SYCONES 


71 


cloaca.     Skeleton  constituted  of  short,  bluiit,  and  bent  uniaxial,  and  also  of 
three-  and  four-rayed  spicules.     Triassic  and  Jurassic. 

Holcospongia  Hinde.  Jurassic  and  Cretaceous.  Sestromostella  Zittel.  Trias 
to  Cretaceous.  Synopella  Zittel.  Cretaceous.  Oculospongia  (Fig.  89)  and 
Diplostoma  From.     Cretaceous. 

Elasmostoma  From.  (Fig.  91).  Foliate-,  ear-,  or  funnel-shaped.  Upper  {i.e. 
inner)  surface  covered  with  smooth  dermal  layer,  in  which  large  shallow  oscula 
are  situated  ;  under  surface  cribriform.     Cretaceous. 

Bhaphidonema  Hinde  (Fig.  92).  Beaker-,  funnel-,  or  twisted  leaf-shaped. 
Inner  or  upper  surface  smooth,  with  very  small  oscula  or  pores.  Outer  surface 
rough,  cribriform.     Canal-system  indistinct.     Trias,  Jurassic,  Cretaceous. 

Pachytylodia  Zitt.  Funnel-shaped,  thick-walled ;  base  with  smooth  dermal 
layer;  oscula  present  here,  but  absent  on  other  parts  of  the  exterior.  Skeleton 
composed  of  very  coarse,  anastomosing  fibres.  Cretaceous.  P.  infmidihulifm'mis 
(Goldfuss). 


Order  2.     SYCONES    Haeckel. 


Walls  traversed  hy  simple  canals  disposed  radially  with  reference  to  the  cloaca 
and  opening  into  it.     Skeletal  elements  very  regulaiiy  arranged. 

Mostly  small  delicate  forms  inhabiting  shallow  water. 

Protosycon  Zitt.,  from  the  Upper  Jurassic  of  Streitberg,  is  a  small,  cylin- 
drical,  or  conical  form  agreeing  with  living  Sycons  in  the  arrangement  of  its 
radial  canals. 

To  the  Sycons,  Rauff  assigns  also  the  calcareous  sponge  Sphinctozoa  described 
by  Steinmann  (Jahrb.  f.  Mine-  a 

ralog.  1882,  IL  p.  139),  which  is 
distinguished  from  all  other 
Calcisponges  by  having  a  most 
remarkable  segmentation,  such 
as  occurs  in  the  Lithistid  genus 
Casearia. 

The  oldest  Sycons  are 
Sollasia,  Amhlysiphonella  and 
Sebargasia  Steinm.,  from  the 
Carboniferous  Limestone  of 
Asturias.  In  the  Triassic  of 
St.  Cassian  and  Seelandalp, 
near  Schluderbach  in  Tyrol, 
are  found  Colospongia  Laube, 
Thaimastocoelia  and  Cryptocoelia  Steinmann.  Thalamopora  Roemer  and  Barroisia 
Steinm.,  occur  in  the  Lower  and  Middle  Cretaceous. 

Barroisia  (Fentriculites  Zitt.  non  Defr.  ;  Sphaerocoelia  Steinm.)  (Fig.  93). 
Occurs  sometimes  as  simple,  cylindrical,  or  clavate  individuals,  and  again  in 
the  form  of  bushy  Stocks.  Outer  surface  frequently  constricted,  summit 
arched,  with  osculum  in  the  centre,  cloaca  tubiform.  The  cylindrical  indi- 
viduals are  composed  of  thin-walled,  hemispherical,  or  compressed  segments, 
which  are  so  arranged  that  the  roof  of  one  segment  serves  also  as  the  floor  of 
the  next  following.    The  wall  is  every where  perforated  by  simple  radial  canals, 


Fig.  93. 


Barroisia  anastomans  (Mantell).  Aptian  ;  Farringdon,  Berk- 
shire. A,  ßush-like  colony,  one  branch  sliced  open ;  natural 
size.  B,  Individual  cut  through  obliquely,  5/2 ;  a,  Junction  of 
two  Segments  ;  6,  Cloaca  ;  0,  Osculum  ;  d,  Radial  canals.  C,  D, 
Three-rayed  skeletal  spicules,  3«/i  and  72/i  (after  Steinmann). 


72  GOELENTEKATA— POEIFERA  phylum  ii 

and  is  made  up  of  fibres  composed  of  three-rayed  spicules.     B.  helvetica  (Lor.). 
Aptian  ;  La  Presta,  Switzerland. 

Appendix  to  Sponges. 

Incertae  seclis. 
Family.     Receptaculitidae    Koemer.i 

This  Singular  group  which  ranges  througbout  the  Ordovician,  Silurian, 
and  Devonian  Systems,  consists  of  globular,  cup-,  or  platter  -  shaped  bodies 
containing  a  central  cavity,  and  whose  wall  is  composed  of  elements  arranged 
in  quincunxial  order.  The  substance  of  the  wall  is  thought  by  Hinde  to  have 
been  siliceous  ;  calcareous  according  to  Kauff ;  aragonite  according  to  Gümbel ; 
calcite  or  chitinous  according  to  Billings,  either  aragonite  or  chitinous  in  the 
opinion  of  Girty.  The  elements  lying  on  the  outer  or  under  side  of  the  wall 
have  been  usually  described  as  consisting  of  small  rhomboidal  plates  having 
four  transverse  rays  disposed  crosswise,  and  one  inwardly  directed  ray  ;  but 
Girty  has  found  evidence  that  the  spicular  summit  plates  are  infiltrations  of 
the  rhombic  pits  of  the  outer  surface,  and  the  radial  pillars  or  spicules  are 
infiltrations  filling  radial  tubes. 

The  systematic  position  of  these  problematic  fossils  is  wholly  conjectural. 
Gümbel  assigns  them  to  the  calcareous  algae  (Dadyloporidae),  and  others  to 
the  Foraminifera  and  Sponges.  Hinde  has  referred  them  to  the  HexadinelUda, 
but  the  observations  of  Eauff  and  Girty  as  to  the  original  calcareous  and 
chitinous  composition  of  the  wall  disprove  this  inference. 

BeceptacuUtes  Defrance.  Spherical  or  pyriform  bodies,  with  a  central  closed 
cavity.     Ordovician  to  Carbon iferous.     Europe,  America  and  Australia. 

Ischadites  Murchison  (Dictyocrinites  Conrad  ;  Didyocrinus  Hall).  Conical  or 
ovate  bodies,  inclosing  a  central  cavity,  with  a  small  summit  aperture  and 
lacking  an  inner  layer.     Ordovician  to  Devonian;  Europe  and  America. 

Here  are  also  referred  Cydocrinus  Eichwald ;  Pasceolus  Billings ;  Polygono- 
sphaerites  Eoemer;  Cerionites  Meek  and  Worthen ;  Lepidolites  and  Anomalospongia 
(Anomaloides)  Ulrich. 

Range  and  Distribution  of  Fossil  Sponges. 

The  phylogeny  of  the  Myxospongiae,  Ceratospongiae  and  a  part  of  the  Silid- 
spongiae,  owing  to  their  perishable  Organisation,  remains  involved  in  doubt. 

1  Salter,  J.  TF.,  CanadianOrganic  Remains,  Dec.  1,  1859.— Hall,  J.,  Pal.  N.  Y.,  vol.  i.,  1847  ; 
Geological  Report  of  Wisconsin,  1862  ;  Sixteentli  Rept.  N.  Y.  State  Cabinet  Nat.  Hist.,  1863  ; 
Twelfth  Rept.  State  Geologist  of  Indiana,  1883  ;  Palaeontology  of  New  York,  vol.  iii.,  1859  ; 
Eleventh  Rept.  State  Geologist  of  Indiana,  1882  ;  Second  Ann.  Rep.  N.  Y.  State  Geologist,  1883  ; 
Palaeontology  of  New  York,  vol.  vi.,  1887. —  Ulrich,  E.  0.,  Jour.  Cincinnati  Soc.  Nat.  Hist.,  vol.  i., 
1871;  vol.  ii.,  1879. — Owen,  D.  />.,  Geol.  Report  Iowa,  Wisconsin  and  Illinois,  1844;  Geol. 
Survey  of  Wisconsin,  Iowa  and  Minnesota,  1852. — Billings,  E.,  Palaeozoic  Fossils,  vol.  i.,  1865  ; 
Canadian  Naturalist  and  Geologist,  second  ser.,  vol.  ii.,  1865 — Meek  and  Worthen,  Geol.  Survey  of 
Illinois,  vol.  iii.,  1868. — Gümbel,  G.  W.,  Abhandl.  der  k.  bayr.  Akad.  Wissensch.,  vol.  xii.,  1875. — 
Roemer,  F.,  Letliaea  Palaeozoica,  1880. — Hinde,  G.  J.,  Quart.  Jour.  Geol.  Soc.  London,  vol.  xl., 
\8M.— James,  J.  F.,  Jour.  Cincinnati  Soc.  Nat.  Hist.,  vol.  viii.,  1885  ;  vol.  xiv.,  ISdl.—  Walcott,  C.  1)., 
Mon.  U.  S.  Geol.  Surv.,  vol.  viii.,  1884:.— Whüßeld,  R.  P.,  Geology  of  Wisconsin,  vol.  iv.,  1884.— 
Rauff,  H.,  Zeitschr.  deutsch,  geol.  Gesellsch.,  vol.  xi.,  1888. — Nicholson  and  Lydekker,  Manual  of 
Palaeontology,  vol.  ii.,  1889 — Winchell  and  Schuchert,  Geol.  of  Minnesota,  vol.  iii.,  pt.  1,  Pal. 
1895.  — Ulrich,  E.  0.,  ibid.,  p.  68— Girty,  G.  //.,  Fourteentli  Ann.  Rept.  N.  Y.  State  Geologist 
for  1894,  1895.  — Weller,  S.,  Geol.  Survey  of  New  Jersey,  Rept.  on  Pal.,  vol.  iii.,  1903. 


I 


RANGE  OF  FOSSIL  SFONGES  73 


Nevertheless,  isolated  spicules  prove  the  existence  of  Monactinellids  and 
Tetractinellids  in  Paleozoic  seas ;  while  in  the  Trias,  Jura  and  Cretaceous 
these  forms  become  important  rock-builders,  and  play  an  active  part  in  the 
formation  of  hornstone,  chalcedony  and  flint.  In  the  Tertiary,  spicules  refer- 
able  to  existing  genera  are  common. 

The  former  distribution  of  the  three  best  preserved  sponge  groups — the 
Lithistids,  Hexactinellids,  and  Calcisponges — is  noteworthy.  The  living  repre- 
sentatives  of  the  first  two  Orders  inhabit  deep  or  moderately  deep  water,  while 
the  calcareous  sponges  predominate  in  shallow  waters  bordering  the  coast. 
And  hence,  since  fossil  Calcisponges  likewise  occur  almost  entirely  in  marly, 
clayey,  or  sandy  strata  of  undoubted  littoral  origin,  and  are  absent  in  lime- 
stones  where  Lithistids  and  Hexactinellids  predominate,  it  is  piain  that  the 
distribution  of  both  fossil  and  Recent  sponges  has  been  occasioned  by  like 
physical  conditions. 

In  the  Cambrian  occur  the  Lithistid  genera  Archaeoscyphia  and  Nipterella, 
and  in  the  Ordovician  and  Silurian  of  Europe  and  North  America  are  found 
a  number  of  Tetracladina  (Aulocopium)  and  Eutaxidadina  forms  {Astylospongia, 
Palaeomanon,  Hindia),  together  with  a  few  Rhizomorina.  In  the  Carboniferous 
ßhizomorina  and  Megamorina  are  sparsely  represented ;  but  in  the  Upper 
Jurassic,  and  especially  in  the  Spongitenkalk  of  Franconia,  Swabia,  Switzer- 
land,  and  the  Krakau  district,  the  Lithistids  exhibit  an  astonishing  develop- 
ment,  and  occasionally  form  thick  beds.  They  occur  only  sparingly  in  the 
Lower  Cretaceous,  but  are  abundant  in  the  Pläner,  Greensand  and  Upper 
Cretaceous  of  Northern  Germany,  Bohemia,  Poland,  Galicia,  Southern  Russia, 
England  and  France.  The  Tertiary  being  nearly  everywhere  made  up  of 
shallow-water  formations,  the  absence  of  Lithistids  and  Hexactinellids  is  not 
surprising.  They  persist  locally,  however,  as  in  the  Upper  Miocene  of  Bologna 
and  in  the  Province  of  Oran  in  Northern  Africa. 

The  ränge  of  the  Hexadinellida  is  in  every  respect  similar  to  that  of  the 
Lithisiida.  Beginning  in  the  Upper  Cambrian,  they  are  represented  in  the 
Ordovician  and  Silurian  by  peculiarly  modified  Lyssacina  forms  (Protospongia, 
Phormosella,  Cyathophycus,  Palaeosaccus,  Pledoderma,  Pattersonia,  Brachiospongia, 
Didyophyton,  Astraeospongia).  The  same  group  continues  also  through  the 
Devonian,  where  Didyophyton  and  its  associates  are  conspicuous  for  their  wide- 
spread  distribution  in  North  America.  A  few  aberrant  Lyssacina,  which  Hinde 
designates  as  Heteradinellidae,  are  found  in  the  Carboniferous.  During  the 
Mesozoic  and  Cenozoic  eras  the  distribution  of  the  Hexadinellida  is  nearly 
identical  with  that  of  the  Lithistida;  although  here  and  there  beds  occur 
which  are  charged  principally  with  Hexactinellids,  and  others  chiefly  with 
Lithistids. 

Very  different  conditions  are  presented  by  the  Calcisponges,  among  which 
only  the  Pharetrones  and  Sycons  are  of  geological  importance.  The  oldest 
calcareous  sponges  occur  very  sparsely  indeed  in  the  Middle  Devonian  and 
Carboniferous  Limestone.  They  appear  in  considerable  diversity  in  the  Alpine 
Trias  (St.  Cassian  and  Seelandalp),  but  outside  the  Alps  are  almost  wholly 
absent.  In  the  Jurassic  they  occur  in  marly  beds  of  the  Dogger  (Ranville, 
Swabia),  and  also  in  certain  facies  of  the  Malm  (Terrain  ä  Chailles,  Coral-Rag 
of  Nattheim,  Sontheim,  etc.)  in  Southern  Germany  and  Switzerland. 

The  Lower  Cretaceous,  particularly  the  Neocomian  of  Brunswick,  the 
Swiss  Jura,  and   the  Paris  Basin,  as  well  as   the  Aptian  of  La  Presta,  near 


74  COELENTEKATA— CNIDARIA  phylum  ii 

Neuchätel,  and  Farringdon,  Berkshire ;  and  also  the  Middle  Cretaceous  (Ceno- 
manian)  of  Essen,  Le  Mans,  and  Havre,  are  characterised  by  an  abundance  of 
well-preserved  Pharetrones,  and  a  lesser  number  of  Sphinctozooid  Sycons.  In 
the  Tertiary,  however,  both  groups  are  wanting,  although  the  existence  of 
calcareous  sponges  is  still  indicated  by  occasional  detached  triactins.  The 
Pharetrones  apparently  become  extinct  at  the  close  of  the  Cretaceous. 

SuBPHYLUM  II.    Cnidaria. 

The  Cnidaria  or  Nematophora  have  a  radially  symmetrical  body,  and  a 
terminal  mouth-opening  surrounded  by  fleshy  tentacles.  In  the  ectoderm 
(sometimes  also  in  the  entoderm)  cnidoblasts  are  common,  from  the  contents 
of  which  thread-cells  (nematocysts)  filled  with  an  urticating  fluid  and  containing 
a  hollow,  spirally  coiled  thread,  are  developed.  Each  cnidoblast  possesses  a 
fine  superficial  process  (cnidocil),  which  is  very  sensitive  to  mechanical  Stimuli, 
The  polyp  wall  typically  consists  of  three  layers :  an  outer  ectoderm,  an  inner 
endoderm,  and  a  middle  mesogloea.  The  mesogloea  is  sometimes  entirely 
absent,  but  the  ectoderm  and  entoderm  are  strongly  developed.  The  ectoderm 
frequently  secretes  a  calcareous  or  horny  skeleton,  and  both  ectoderm  and 
entoderm  are  concerned  in  the  production  of  muscles  and  nerves.  The  sexual 
Organs  are  the  product  of  the  entoderm. 

The  Cnidaria  are  divided  into  two  classes :  Anthozoa  and  Hydrozoa.  The 
latter  are  undoubtedly  the  more  primitive  group,  but  it  will  be  convenient  to 
treat  of  the  Anthozoa  first  in  the  present  work. 

Olass  1.    ANTHOZOA  =  A0TINOZOA.    Coral  Polyps.i 

Usually  sessikj  cylindrical  polyps,  possessing  a  mouth  surrounded  by  tentacles, 
Oesophagus,  and  gastrovascular  cavity.  The  latter  is  divided  by  numerous  vertical 
partitions  (mesenteric  folds)  into  a  System  of  radially  disposed  pouches.  A  calcareous 
or  horny  skeleton  is  frequently  developed.     Simple  or  forming  colonies. 

The  simple  polyp  zooids  have  the  form  of  a  cylindrical  or  conical  tube 
at  the  distal  end  of  which  is  situated  a  muscular  disk  perforated  centrally  by 

^  Literature  :  Milne  Edwards,  H.,  et  Haime,  J.,  Histoire  naturelle  des  coralliaires,  3  vols.  and 
atlas.  Paris,  1857-60. — Idem,  Monographie  des  polypiers  fossiles  des  terrains  paleozoiques.  Arch.  du 
Museum,  Paris,  vol.  v.,  1851. — Idem,  Monograph  of  the  British  Fossil  Corals.  Palaeontogr.  Soc, 
1849-64. — Fromentel,  E.  de,  Introduction  a  l'etude  des  polypiers  fossiles.  Paris,  1858-61. — Idem, 
Paleontologie  frangaise  ;  1861  and  later. — Reuss,  A.  E.,  Articles  in  Sitzber.  Akad.  Wiss.  Wien,  1859, 
1864, 1865,  1870 ;  also  Denkschr.  vols.  vii.,  xxiii.,  xxviii.,  xxix.,  xxxi.,  xxxiii. — Duncan,  P.  M.,  British 
Fossil  Corals,  2d  ser.  Palaeontogr.  Soc.  1865-69,  and  1872. — Idem,  Revision  of  the  Families  and 
Genera  of  the  Sclerodermic  Zoantharia  or  Madreporaria.  Journ.  Linn.  Soc.  Zoology,  1885,  vol. 
xviii. — Kohy,  F.,  Monographie  des  polypiers  jurassiques  de  la  Suisse.  Abhandl.  Schweiz.  Pal.  Ges., 
1880-94,  vols.  vii.-xxii. — Pratz,  E.,  Ueber  Septalstructur.  Palaeontogr.  1882,  vol.  xxix. — Koch, 
G.  von,  Die  ungeschlechtliche  Vermehrung  der  paläozoischen  Korallen. — Ibid.,  1883,  vol.  xxix. — 
Quenstedt,  F.  A.,  Petrefactenkunde  Deutschlands,  1889,  vol.  vii. — Kohy,  F.,  Monographie  des  poly- 
piers cretaces  de  la  Suisse.  Abhandl.  Schweiz.  Pal.  Ges.  1896-98,  vols.  xxii.-xxiv. — Ogüvie-Gordon, 
Maria  M.,  Korallen  der  Stramberger  Schichten.  Palaeontographica,  Supp.  II.,  1897. — Idem, 
Systematic  Study  of  Madreporarian  Types  of  Corals.  Phil.  Trans.  Roy.  Soc.  London,  1897,  ser. 
B,  vol.  clxxxvii. — Gregory,  J.  W.,  I^he  Corals,  Jurassic  Fauna  of  Cutch.  Palaeontol.  Indica,  1900, 
ser.  2,  vol.  ix.,  pt.  2.  —  Vaughan,  T.  Wayland,  Eocene  and  Lower  Oligocene  Coral  Faunas  of  the 
United  States.  Mon.  xxxix,  U.S.  Geol.  Survey,  1900. — Ide7n,  Critical  Review  of  the  Literature  on 
the  simple  Genera  of  the  Madreporaria  Fungida.  Proc.  U.S.  Nat.  Mus.,  1905,  vol.  xxviii. — 
Buerdeii,  J.  E.,  West  ludian  Madreporarian  polyps.     Mem.   Nat.  Acad.,  1902,  vol.   viii, — Idem, 


5S  I 


ANTHOZOA 


75 


^^|l|e  slit-like  or  oval  fissure  of  the  mouth.  The  oral  disk  is  furnished  with  a  ring 
of  tentacles  round  its  margin,  and  opeiis  into  a  membranous  oesophageal  tube 
conducting  into  the  gastric  cavity.  The  outer  covering  of  the  body,  the  parts 
of  which  are  designated  as  wall,  oral  disk,  and  pedal  disk,  are  constituted  of 
ectoderm  and  entoderm,  between  which  is  a  thin  layer  of  mesoderm  (mesogloea). 
Six,  eight,  or  more  radially  disposed  vertical  partitions  (mesenteries),  (Figs.  94, 
95),  projecting  inwardly  from  the  body-wall,  divide  the  gastric  cavity  into  a 
series  of  radiating  compartments  (mesenteric  pouches).  The  mesenteries  are 
continuous  upwardly  with  the  hollow,  muscular  tentacles  ;  while  the  generative 
Organs  are  attached  to  their  faces  near  the  lower  end  of  the  body.  The 
mesenteries  are  »covered  on  both  sides  with  muscular  tissues,  and  bear  mesen- 
teric filaments  on  their  curled  inner  edges.  On  one  side  of  the  mesenteries 
the  muscle  fibres  are  transversely  directed,  on  the  other  longitudinally.  The 
longitudinal  System  is  usually  considerably  folded  and  thickened ;  and  the 
disposition  of  these 
muscular  portions  is  of 
great  importance  from  a 
systematic  standpoint, 
since  it  reveals  the 
bilateral  symmetry  of 
many  Anthozoans,  and 
enables  one  readily  to 
identify  the  antimeres. 
If  a  polyp  individual  be 
cut  in  two  by  a  plane 
passing  through  the 
longer  axis  of  the 
mouth-opening,  then,  in 
the  Octocoralla  (Fig 
94),  the  mesenteries  of 
the  right  half  will  have 

all  the  muscular  thickenings  disposed  on  the  right-hand  side,  and  those  of  the 
left  on  the  left-hand  side.  In  the  Hexacoralla  (Fig.  95)  the  mesenteries  are 
grouped  in  pairs,  with  the  muscular  thickenings  of  any  pair  facing  each  other. 
Two  pairs,  however  (those  corresponding  with  the  opposite  extremities  of  the 
longitudinal  mouth),  form  often  an  exception  to  this  rule,  since  these  have  the 
muscular  thickenings  placed  on  opposite  sides.  These  are  called  the  directive 
mesenteries,  and  serve  to  indicate  the  longitudinal  axis  of  the  body. 

Only  a  few  Anthozoa  have  permanently  soft  bodies ;  the  majority  secreting 
calcareous,  horny,  or  partly  horny  and  partly  calcareous  structures,  termed  the 
skeleton  or  corallum.  The  simplest  form  of  corallum  is  that  composed  of 
microscopic,  round,  cylindrical,  acerate,  or  tuberculated  spicules  of  carbonate 


Fig.  94. 

Diagrammatic  section  of 
the  soft  parts  of  an  Octo- 
coralla (Alcyoninm).  x,  Oeso- 
phagus ;  1,  2,  3,  4,  Mesen- 
teries of  the  left  side  (after 
R.  Hertwig). 


Fig.  95. 

Diagrammatic  section  of  the  soft  parts  of 
a  Hexacoralla.  In  the  upper  half  (above  the 
line  a — h)  the  section  passes  through  Oeso- 
phagus s ;  in  the  lower  half,  beneath  the 
same.  Corallum  indicated  by  heavy  lines. 
r,  directive  mesenteries. 


Morphology  of  the  Madreporaria.  A  series  of  papers  in  Ann.  and  Mag.  Nat.  Hist.,  ser.  7,  vols.  ix., 
X.,  xi.,  xvii.,xviii.  (1902-1906),  and  Biol.  Bull.,vols.  vii.  and  ix.  (1904-1905).— /rfew,  Recent  Results  on 
the  Morpliology  and  Development  of  Coral  Polyps.  Smithsonian  Miscellaneous  Collections,  Quart.  Lss., 
1904,  vol.  xlvii. — Felix,  J.,  Die  Anthozoen  der  Gosan  Schichten  in  den  Ostalpen.  Palaeontographica, 
1903,  vol.  xlix.  Nuinerous  other  papers,  especially  in  Zeitsch.  deutsch,  geol.  Gesellsch. — Caimthers, 
R.  G.,  The  primary  Septal  Plan  of  the  Rugosa.  Ann.  and  Mag.  Nat.  Hist.  1906,  ser.  7,  vol.  xviii. — 
Gordon,  O.  E.,  Studies  on  early  Stages  in  Paleozoic  corals.  Am.  Jour.  Sei.,  1906,  vol.  xxi. — Bnrwn, 
T.  0.,  Studies  on  the  Morphology  and  Development  of  certain  Rugose  Corals.  Ann.  N.Y.  Acad.  Sei., 
1909,  vol.  xix. 


76 


COELENTERATA— CNIDARIA 


PHYLÜM  II 


of  lime,  which  are  developed  in  great  quantities  and  remain  detached  in  the 
soft  parts  (many  .Alcijonaria).  In  a  number  of  forms  (Corallium,  Mopsea, 
Tubipora)  the  spicules  are  firmly  cemented  together  hy  means  of  a  calcareous 
or  horny  connective  substance,  in  such  a  manner  as  to  form  tubes  (Tubipora), 
or,  when  the  secretion  takes  place  chiefly  at  the  base,  a  sclerobase,  or  axis. 
Surrounding  the  axis  is  the  soft  coenosarc  in  which  the  polyps  of  the  colony 
are  embedded  (Fig.  96).  In  some  cases  the  sclerobase  is  composed  entirely  of 
horny  matter  without  admixture  of  calcareous  secretions.  In  the  so-called 
"stone  corals"  (Fig.  97)  a  consistent  calcareous  skeleton  is  formed  by  the 
oiiter  surface  of  the  ectoderm.  At  the  base  of  the  polyp  between  each  pair 
of  mesenteries,  the  infolded  ectoderm  secretes  small,  round,  cgi^al  or  irregulär 
calcareous  bodies  (sderites) ;  these  are  opposed  against  one  another  in  radial 
directions,  and  as  others  are  successively  laid  down  on  top  of  them,  upright 


Corallium  rubrum  Lam.  (after  Lacaze-Duthiers). 
Brauch  of  red  coral  of  commerce  laid  open  along  the  axis, 
and  showing  three  polyps  in  section  embedded  in  fleshy 
coenosarc. 


Fig.  97. 

Astroides  calycularis  (Lamx.).  Mediterran ean 
(alter  Lacaze-Duthiers).  Enlarged  longitudinal 
section  of  polyp  with  calcareous  skeleton.  te, 
Tentacles  ;  oe,  Oesophagus  ;  me,  Mesentery  ;  loc, 
Mesenteric  pouches  ;  coe,  Coenosarc  ;  spt,  Septum  ; 
col,  Columella. 


partitions  or  septa  are  built  up.  Early  in  development  also,  after  fixation  of 
the  larva,  the  basal  plate  becomes  calcified,  owing  to  the  secretion  by  the  outer 
surface  of  the  ectoderm  of  numerous  minute  calcareous  granules  (calicoblasts). 
The  septa,  however,  grow  considerably  above  the  base,  and  become  lodged  in 
the  vertical  interspaces  between  the  mesenteries.  In  the  same  manner,  within 
the  soft  body-wall,  a  calcareous  secretion  may  take  place,  binding  the  outer 
borders  of  the  septa  together,  and  known  as  the  wall  or  theca.  Both  septa  and 
theca  are  composed  of  minute,  densely  crowded  calcareous  bodies,  in  which 
delicate  calcareous  fibres  may  be  seen  radiating  in  all  directions  from  a  central 
dark  space.  And  since  all  the  calcareous  bodies  forming  the  septa  have  a 
radial  disposition,  the  calcification-centres  as  seen  in  transverse  sections  form 
a  dark,  mostly  interrupted  and  occasionally  jagged  median  line,  from  which 
bundles  of  minute  fibres  radiate  outward  in  all  directions.  Similar  calcification- 
centres  may  also  be  found  in  the  theca.  Sometimes  the  median  dark  line  is 
uninterrupted  and  divides  the  septum  into  two  separate  lamellae. 


i. 


ANTHOZOA 


77 


The  interstices  between  the  sclerites  forming  the  septa  are  either  com- 
pletely  filled  with  carbonate  of  lime  (Aporosa),  or  there  remain  larger  or 
smaller  porous  Spaces  (Ferforata) ;  in  many  cases,  in  fact,  the  septa  are 
represented  by  a  loose  network  of  sclerites  piled  up  vertically,  or  merely  by 
vertically  directed  spines. 

The  number  of  septa  and  of  tentacles  is  either  equal  to  the  number  of 
pairs  of  mesenteries  (when  only  entocoelic  septa  are  present),  or  double  that 
of  the  pairs  of  mesenteries  (when  both  exocoelic  and  entocoelic  septa  and 
tentacles  are  present),  and  is  somewhat  uniform  throughout  species,  genera 
and  higher  groups.  The  number,  width  and  mode  of  formation  of  the 
septa  furnish  important  systematic  characters.  As  the  locus  of  the  origin  of 
the  septa  succeeding  the  primaries  may  conform  to  one  of  several  plans,  this 
character  is  used  in  determining  the  major  groups.  The  upper  edges  of  the 
septa  are  sometimes  smooth,  sometimes 
serrated  or  granulated ;  and  they  extend 
from  the  central  depression  to  or  through 
the  walls  of  the  theca,  either  obliquely  or 
in  a  curved  line.  This  open,  central  depres- 
sion, formed  by  the  superior  edges  of  the 
septa,  is  known  as  the  calice  or  calyx. 

The  sides  of  the  septa  are  rarely  smooth, 
but  are  commoniy  granulated  or  furnished 
with  rows  of  small  prominences ;  occasion- 
ally  they  are  provided  with  well-marked 
vertical  cross-bars  (carinae).  When  the 
projections  on  the  sides  of  the  septa  are 
in  the  form  of  conical  or  cylindrical  trans- 
verse  bars,  they  are  termed  synapticulae. 
Frequently  the  synapticulae  of  two  adjacent 
septa  become  joined  together ;  sometimes 
whole  rows  of  them  are  fused  together 
to  form  perpendicular  bars,  thus  greatly 
strengthening  the  septal  framework.  In 
some  corals  (athecalia)  the  development  of 
synapticulae  is  such  as  to  render  an  outer 
wall  superfluous.  With  the  upward  growth  of  the  polyp,  the  theca  gradually 
becomes  elevated,  and  its  lower  portions,  as  their  occupation  by  the  soft  parts 
ceases,  may  be  partitioned  ofF  by  numerous  horizontal  or  oblique  calcareous 
plates  which  bridge  over  the  interseptal  Spaces.  These  structures  are  known  as 
dissepiments  and  tabulae.  The  tabulae  are  often  nothing  but  highly  developed 
dissepiments,  being  distinguished  from  the  latter  merely  by  the  fact  that  they 
extend  across  between  the  septa  at  the  same  level;  sometimes  they  are 
perfectly  horizontal,  sometimes  they  are  arched  or  funnel-shaped  (Fig.  98), 
and  sometimes  incomplete.  Dissepiments  and  tabulae  are  most  strongly 
developed  in  cylindrical  forms,  and  frequently  fill  the  included  space  within 
the  theca  with  a  vesicular  or  cellular  tissue. 

When  a  number  or  when  all  of  the  septa  are  produced  as  far  as  the  centre 
of  the  calice,  their  inner  edges  may  become  twisted  so  as  to  form  an  axial 
structure,  known  as  a  pseiidocolmnella.  Sometimes,  however,  a  true  columella 
is  present ;  this  may  be  either  a  compact,  styliform  or  foliaceous  structure,  or 


Lithostrotion 
martini  B.  and  H. 
Longitudinal  sec- 
tion  showing 
tabulae. 


Fig.  99. 


CaryophylUa  cyathus  Sol. 
Corallum  split  open  longi- 
tudinally  ;  true  columella 
in  the  centre,  surrounded 
by  a  cycle  of  pali. 


18  COELENTERATA— CNIDARIA  phylum  ii 

may  be  composed  of  a  bündle  of  styliform  or  twisted  rods  (Fig.  99),  or  of  thin 
lamellae.  It  extends  from  the  floor  of  the  visceral  Chamber  to  the  bottoni  of 
the  calice,  into  which  it  projects  for  a  greater  or  less  distance.  The  structures 
known  as  pali  are  narrow  vertical  plates  which  are  inserted  between  the  colu- 
mella  and  the  inner  ends  of  the  septa  in  one  or  more  cycles  (Fig.  99). 

The  outer  wall  or  theca  is  often  formed  by  the  secretion  of  a  particular 
ring-like  fold  of  the  ectoderm,  and  is  constituted  of  distinct  sclerites,  having 
separate  calcification-centres,  and  connecting  the  outer  borders  of  the  septa 
(euthecalia).  In  many  cases  the  peripheral  edges  of  the  septa  become  thickened 
and  laterally  fused  to  form  a  spurious  theca  (pseudothecalia) ;  and  occasionally 
the  dissepiments  lying  in  a  certain  zone  become  united  so  as  to  form  an  inner 
wall  within  the  true  theca.  The  epitheca  is  a  usually  smooth,  sometimes  corru- 
gated,  superficial  calcareous  investment,  which,  according  to  Koch,  is  merely  a 
Prolongation  of  the  basal  plate,  and  is  secreted  by  the  outer  surface  of  the 
ectoderm,  which  is  reflected  over  the  top  of  the  corallum.  The  epitheca  is 
deposited  either  directly  upon  the  septa,  or  upon  the  theca,  or,  when  the  septa 
are  produced  outwards  so  as  to  form  exothecal  lamellae  or  ribs  (costae),  the 
theca  and  epitheca  are  separated.  Exothecal  lamellae,  not  corresponding  in 
Position  to  the  septa,  are  called  pseudocostae  or  rugae. 

New  individuals  or  colonies  commonly  originate  by  sexual  reproduction. 
Following  fertilisation  and  segmentation  of  the  ova,  ciliated  larvae  are  born, 
which  swim  about  for  a  time,  become  fixed,  and  develop  into  simple  polyp 
individuals.  Vegetative  or  asexual  increase  by  two  sharply  defined  processes, 
namely,  hudding  (or  gemmation)  and  ^jssiow,  assumes  a  great  importance  among 
Anthozoans,  resulting  in  the  production  of  colonies  or  Stocks,  often  of  large 
size  and  exceeding  complexity  of  form. 

New  corallites  are  produced  either  within  or  without  the  calice  of  the 
parent  polyp.  In  extra-calicinal  gemmation  the  buds  are  thrown  out  either 
from  the  sides  of  the  polyp  (lateral  gemmation),  or  are  formed  in  the  common 
calcareous  matrix  which  unites  the  various  corallites  of  a  colony  {coenenchymal 
and  costal  gemmation).  In  both  cases  the  new  corallites  may  diverge  from  one 
another,  being  attached  to  the  parent  corallum  only  at  the  base,  or  they  may 
grow  up  closely  opposed  to  the  latter  and  to  one  another,  so  that  the  thecae 
are  in  contact  on  all  sides.  In  this  way  branched,  dendroid  or  massive  and 
knob-like  '("astraeiform")  Compound  coralla  are  formed.  A  less  common 
mode  of  increase  is  by  hasal  or  stolonal  gemmation.  In  this  process  the  wall  of 
the  original  polyp  sends  out  creeping  prolongations  (stolons)  or  basal  expansions, 
from  which  new  corallites  arise.  In  calicinal  gemmation  buds  are  produced 
within  the  calice  of  the  parent  corallite,  according  to  one  or  the  other  of  the 
following  methods  :  either  certain  particular  septa  become  enlarged  and  pro- 
duced so  as  finally  to  enclose  a  new  calicinal  disk  {septal  gemmation) ;  or  tabulae 
are  produced  upwards  in  the  form  of  pockets,  from  which  new  corallites  are 
developed  (tahular  gemmation).  In  both  septal  and  tabular  gemmation,  a  portion 
of  the  parent  corallite  including  a  part  of  the  original  wall  is  concerned  in  the 
formation  of  buds ;  while  the  septa  or  modified  tabulae  are  converted  into 
portions  of  the  new  thecae,  from  which  new  septa  then  begin  to  grow  inwards 
towards  the  centre. 

A  peculiar  kind  of  calicinal  gemmation  is  that  known  as  rejuvenescence.  In 
this  method  only  one  bud  is  formed  within  the  parent  calice,  but  it  enlarges 
aintil  it  completelj  ßlls  the  latter.     By  the  indefinite  repetition  of  this  process,  a 


CLASS  I  ANTHOZOA  79 

corallum  is  formed,  consisting  of  a  succession  of  cups  placed  one  within  the  other, 
of  which  only  the  youngest  and  uppermost  is  occupied  by  the  living  animal. 

The  beginning  of  reproduction  by  fission  is  marked  by  an  elongation  or 
distortion  of  the  parent  calice,  accompanied  by  the  contraction  of  the  wall  at 
opposite  points  along  the  margin.  The  constriction  may  proceed  until  it 
divides  the  oral  disk  into  two  halves;  or  two  opposite  septa  may  unite  to  form 
a  new  theca.  By  this  method  branching,  massive  or  "  astraeiform  "  colonies 
are  produced,  which  do  not  difFer  essentially  from  those  formed  by  budding. 
Frequently,  however,  individuals  formed  by  fission  become  only  imperfectly 
separated,  remaining  proximally  more  or  less  closely  confluent.  In  such  cases 
the  calices  form  continuous,  straight,  curved  or  labyrinthic  furrows,  with  more 
or  less  clearly  distinguishable  centres. 

The  Compound  corallum  of  a  polyp  stock  remains  practically  the  same  as  in 
solitary  individuals,  excepting  that  the  conditions  are  more  complicated  when 
the  Separation  of  the  zooids  is  incomplete.  Dendroid  and  massive  colonies 
frequently  develop  a  common  connective  matrix  or  tissue  (coenenchyma)  which 
unites  the  various  corallites  into  a  whole;  it  is  secreted  by  the  common 
colonial  flesh,  called  coenosarc,  which  extends  as  a  carpet  between  the  polyps, 
The  coenenchyma  is  sometimes  dense  in  structure  {Oculinidae),  or  it  may  consist 
of  a  vesicular  or  tubulär  tissue.  The  separate  corallites  are  often  also  united 
by  means  of  the  septa,  which  are  produced  over  and  beyond  the  thecae,  and 
fused  with  those  of  neighbouring  individuals.  In  such  cases  the  interseptal 
loculi  are  almost  always  filled  with  strongly  developed  dissepiments.  All 
structures  developed  in  the  included  space  within  the  theca,  with  the  exception 
of  the  septa  and  columella,  are  designated  coUectively  as  endotheca  ;  those  lying 
without  the  theca  as  exotheca. 

The  Anthozoa  are  exclusively  marine  forms,  and  predominate  in  shallow 
water.  Many  of  the  Adiniaria,  Antipatharia  and  Madreporaria  occur  also  at 
greater  depths,  ranging  from  50  to  300  and  sometimes  to  over  3000  fathoms. 
The  so-called  reef-corals  inhabit  depths  usually  not  exceeding  45  metres,  and 
require  a  temperature  of  the  water  of  20°  C,  or  higher.  Hence,  existing 
coral-reefs  are  restricted  to  a  zone  exfcending  about  30"  on  either  side  of  the 
equator ;  they  are  distinguished  according  to  form  as  fringing  reefs,  barrier 
reefs  and  atolls.  While  the  stony  corals  (Porifes,  Acropora,  Turbinaria, 
Pocillopora,  numerous  '^ Astraeidae"  and  Fungidae)  and  the  Alcyonarians 
(Heliopora)  are  the  most  important,  they  are  not  the  only  agents  concerned  in 
the  formation  of  reefs,  as  an  active  part  is  also  played  by  the  Hydromedusae 
(Milleporidae),  calcareous  algae  (Lithothamnium,  Melobesia),  mollusks,  echino- 
derms,  bryozoans  and  worms.  Of  the  ancient  coral-reefs  which  have  been 
formed  in  nearly  all  of  the  great  geological  periods,  those  of  the  Cenozoic  and 
Mesozoic  periods  are  composed  in  part  of  genera  similar  to  those  now  living ; 
while  those  of  the  Paleozoic  represent  genera  and  families  that  are  now 
principally  extinct,  and  whose  relation  to  living  forms  is  often  quite  uncertain. 

The  Anthozoa  are  divided  by  Haeckel  into  three  subclasses :  Tetracoralla, 
Hexacoralla  and  Alcyonaria  or  Octocoralla.  Of  these  the  two  first-named  groups 
are  by  some  authors  collectively  termed  Zoantharia. 


80  COELENTERATA— ANTHOZOA  phylüm  ii 

Subclass  1.     TETRAOORALLA    Haeckel.^ 

{Zoantharia  Eugosa  Milne  Edwards  ;  Fterocorallia  Frech.) 

Extinct,  Faleozoic,  simple  or  composite  sderodermic  corals,  with  septa  arranged 
according  to  a  tetrameral  System,  and  either  Ulaterally  or  radially  symmetrical  ; 
wühout  coenenchyma,  hut  with  usually  strongly  developed  endothecal  tissue  in  the  form 
of  tabulae  or  dissepiments,  and  with  well-marked,  frequently  wrinkled  epithecal  wall. 

The  Tetracoralla  are  especially  characterised  by  having  the  septa,  subse- 
quent  to  the  formation  of  the  primaries,  introduced  along  four  lines  rising 
from  the  apex  of  the  base  of  the  corallum.  The  earlier  stages  of  the  Tetra- 
coralla have  recently  been  reinvestigated  by  Duerden,  Carruthers  and  others. 
Duerden  concluded  that  the  observations  of  Ludwig  and  Pourtales  on  the 
primary  hexamerism  of  these  corals  were  correct.  According  to  Carruthers, 
in  the  developing  young  Tetracoralla  the  first  stage  of  septal  formation  is  for 
a  Single  septum  to  stretch  entirely  across  the  calice  from  wall  to  wall.  This 
septum,  which  is  called  the  axial  septum,  later  breaks  up  to  form  the  main 
(cardinal)  and  the  counter  septum  of  the  mature  coral.  In  the  next  stage  a 
small  septum  appears  on  each  side  of  the  main  septal  end  of  the  axial  septum. 
These  two  septa  form  the  alar  septa  of  the  mature  corallum.  In  the  third 
stage  two  other  septa  appear,  one  on  each  side  of  the  counter  septal  end  of  the 
axial  System.  After  the  formation  of  these  six  septa  there  is  a  distinct  pause 
in  the  formation  of  new  septa  and  any  irregularity  in  the  disposition  of  the 
septa  is  corrected.  Four  of  the  six  septa  are  called  principal,  and  are  con- 
spicuous  in  the  later  septal  arrangement ;  these  four  are  the  main,  counter, 
and  alar  septa.  Two  of  the  first  six  septa,  one  on  each  side  of  the  end  of  the 
counter  septum,  are  not  so  prominent  in  subsequent  development. 

There  is  a  controversy  as  to  whether  the  primary  septa  of  the  Tetracoralla 
are  four  or  six  in  number :  Duerden  and  Carruthers  holding  the  number  to  be 
six,  while  Brown  and  Gordon  contend  that  it  is  four.  The  four  principal  septa 
are  sometimes  of  equal  proportions,  when  they  may  be  either  stouter  and 
longer  than  the  others  (Stauria),  or  thinner  and  shorter  (Omphyma) ;  or  they 
may  be  of  unequal  proportions.  Of  the  two  principal  septa  which  lie  in  the 
longitudinal  axis  of  the  corallum,  one  (called  the  main  or  cardinal  septum)  is 
frequently  situated  in  a  depression  or  furrow  known  as  the  fossula  (Fig.  100); 
while  the  other  or  counter  septum  is  either  normally  developed,  or  is  more  or 
less  reduced.  Occasionally  the  counter  septum  is  placed  in  a  fossula,  while 
the  cardinal  septum  is  normally  developed ;  but  the  two  laterally  disposed  or 
alar  septa  are  always  equal  in  size.  The  remaining  septa  not  infrequently 
exhibit  a  well-marked  radial  arrangement,  in  which  the  longer  and  more 
strongly  developed  usually  alternate  with  the  shorter  and  less  strongly 
developed.  New  septa,  according  to  Kunth  and  Dybowski,  are  inserted  in 
the  foUowing  order.     First,  a  new  septum  is  given  ofF  on  either  side  of  the 

1  Literature  :  Kunth,  A.,  Beiträge  zur  Kenntniss  fossiler  Korallen.  Zeitschr,  deutsch,  geol. 
Ges.,  1869-70,  vols.  xxi.,  xxii. — Dybowski,  W.  N.,  Monographie  der  Zoantharia  Eugosa,  etc.  Archiv 
für  Naturkunde  Liv-,  Est-,  und  Kurlands,  1874,  vol.  v. — Roemer,  F.,  Lethaea  Palaeozoica,  1883, 
pp.  324-416. — Schlüter,  dem.,  Anthozoen  des  rheinischen  Mittel-Devons.  Abhandl.  j^reuss.  geol. 
Landes-Anstalt,  1889,  vol.  viii. — Brown,  T.,  Studies  on  the  Morphology  and  Development  of  certain 
Rugose  Corals.  Ann.  N.Y.  Acad.  Sei.,  1909,  vol,  xix. — Faurot,  L.,  Affinites  des  Tetracoralliaires 
et  des  Hexacoralliaires.     Annales  de  Paleont.,  1909,  vol.  iv. 


i... 


TETRACORALLA 


81 


Cardinal  septum  (Fig.  100,  Ä),  and  takes  up  a  position  parallel  with  the  alar 
septum.  This  leaves  an  intermediate  space  between  the  cardinal  and  the 
newly  formed  septa,  which  becomes  filled,  however,  by  the  repeated  insertion 
of  new  septa  one  above  the  other  in  the  same  manner  as  the  first ;  and  hence 
they  diverge  from  the  cardinal  septum,  as  they  grow  upward,  in  a  pinnate 
fashion.  Likewise  the  two  counter  quadrants  lying  between  the  alar  and 
counter  septa  become  occupied  by  lamellae  which  are  given  ofF  from  the  alar 
septa,  and  gradually  arrange  theraselves  parallel  with  the  counter  septum. 
The  mode  of  growth  in  the  Tetracoralla  will  be  readily  understood  on  inspect- 
ing  the  surface  of  those  specimens,  the  septa  of  which  are  visible  on«  the 
exterior,  or  where  the  wall  is  readily  removed  by  corrosion  or  polishing.  One 
may  then  note  three  distinct  lines  extending  from  the  calicinal  margin  to  the 
base ;  these  mark  the  cardinal  and  the  two  alar  septa,  from  which  the  other 
pinnately  branching  septa  are  directed  obliquely  upward  (Fig.  101).  The 
Order  in  which  the  septa  are  given 
ofF  in  the  four  quadrants,  according 
to  Kunth,  is  indicated  by  the 
numerals  in  Fig.  100. 

Many  of  the  Tetracoralla  multiply 
only  by  sexual  reproduction,  and  occur 
only  as  single  individuals ;  asexual 
reproduction  takes  place  usually  by 
calicinal,  more  rarely  by  lateral  gem- 
mation,  and  results  in  dendroid  or 
massive  colonies.  ' 

Dissepiments  are  generally  abund- 
antly  developed  between  the  septa, 
which  latter  are  compact,  and  the 
Upper  edges  of  which  are  either 
smooth  or  serrated.  Sometimes  the 
dissepiments  fiU  the  whole  interior 
with  a  vesicular  tissue,  and  the 
central  visceral  cavity  is  frequently 
entirely  partitioned  off  by  horizontal, 

inclined  or  funnel-shaped  tabulae.  The  wall  is  usually  composed  of  the 
thickened  and  fused  septal  edges;  sometimes  it  is  invested  with  epitheca 
and  furnished  with  vertical  rugae  or  root-like  processes.  A  true  coenenchyma 
is  absent.  In  a  few  genera  the  calice  is  provided  with  a  lid  or  operculum, 
which  may  be  composed  of  one  (Calceola)  or  of  several  plates  (Goniophyllum), 

With  the  exception  of  a  few  genera  the  systematic  position  of  which  is 
uncertain,  all  the  typical  Tetracoralla  are  confined  to  the  Paleozoic  rocks. 

Family  1.     Oyathaxonidae    Milne  Edwards  and  Haime. 

Turbinate  or  horn-shaped  simple  coralla.  Septa  with  regulär  radial  arrange- 
ment.     Tabulae  and  dissepiments  absent.     Silurian  to  Permian. 

Cyathaxonia  Mich..  (Fig.  102).  Acutely  pointed,  conical.  Cardinal  septum 
in  fossula.  Septa  numerous,  extending  inward  as  far  as  the  strongly  developed 
styliform  and  considerably  elevated  columella.  Carboniferous  limestone ; 
Belgium  and  England. 

VOL.  I  0 


Fig.  100. 

Menophyllum  tenuimar- 
ginatum  B.  and  H.  Car- 
boniferous Limestone ; 
Tournay,  Belgium.  2/j. 
h,  Cardinal  septum ;  g, 
Counter  septum ;  s,  Alar 
septa. 


Streptelasma  profundum 
(Owen).  Ordovician ;  Cin- 
cinnati,  Ohio.  Natural 
size. 


82 


COELENTEEATA— ANTHOZOA 


PHYLUM  II 


Duncanella  Nich.  Corallum  top-shaped.  Septa  nearly  all  of  uniform 
length  and  size,  forming  a  spurious  columella  in  centre  of  the  deep  calice, 
exsert  at  the  base.     Silurian ;  North  America.     D,  horealis  Nich. 

Fetraia  Münst.  (Fig.  103).  Turbinate  or  conical.  Septa  short,  reaching 
to  the  centre  only  at  the  base  of  the  very  deep  calice.  Columella  absent. 
Ordovician  to  Carboniferous. 

Folycoelia  King  (Fig.  104).  Horn-shaped.  Calice  very  deep;  four  prin- 
cipal  septa  reach  nearly  to  its  centre,  between  which  in  each  quadrant  are 
five  shorter  septa.     Zechstein. 

Kanophyllum  Dyb.     Ordovician  and  Silurian. 


Fig.  102. 

Cyathaxonia 
cornuMich.  Car- 
boniferous Lime- 
stone ;  Tournay, 
Belgiiim.  Cor- 
allum with 
fractured  theca, 
showing  open  in- 
terseptal  loculi. 

2/1. 


Fig.  103. 

Petraia  radiata 
Münster.  Devonian; 
Enkeberg,  near 
Brilon,  i/i.  a,  Cor- 
allum viewed  from 
the  apex;  b,  Trans- 
verse section  below 
the  middle. 


Fig.  104. 

Folycoelia  pro- 
funda (Germ.). 
Zech  stein; 
Gera.  Vi(after 
Roemer). 


Fig.  105. 

Falaeocydus  porpita 
(Linn.).  Silurian; 
Gotland.  a,  Top 
View  of  calice ;  h, 
Profile,     i/i- 


Fig.  106. 

Microcyclus  dis- 
cus  Meek  and 
Worth.  Hamil- 
ton (Devonian) ; 
North  America. 
i/j.  a,  Corallum 
from  below  ; 
b,  from  .  above 
(after  Nicholson). 


.    Family  2.     Palaeocyclidae   Dybowski. 

Coralla  simple,  discoidal  or  howl-shaped.      Septa  numerous,  stout,  approaching 
radial  symmetry  in  disposition.     Tabulae  and  dissepiments  waiiting. 


Palaeocyclus  E.  and  H.  (Fig.  105).  Discoidal  to  depressed  top-shaped, 
with  epitheca.  Septa  numerous,  radially  disposed,  the  larger  ones  reaching 
to  the  centre.     Silurian.     Type,  P.  porpita  (Linn.). 

Combophyllum,  Baryphyllum  E.  and  H.    Devonian. 

Hadrophyllum  E.  and  H.  Cushion-shaped,  with  epitheca.  Calice  with 
three  septal  fossula,  that  of  the  cardinal  septum  being  the  largest,  Devonian; 
Eifel  and  North  America. 

Microcyclus  Meek  and  Worth.  (Fig.  106).  Like  the  preceding,  but  with 
only  one  septal  fossula.     Devonian ;  North  America. 


Family  3.     Zaphrentidae    Milne  Edwards  and  Haime. 


turbinate,    conical  or    cylindrical ;    septa   numerous,  exhihiting 

Theca  generally  formed  hy  fusion  of 

s  not  very  ahundant  in  inter- 


Coralla  simple, 
distinct  bilateral  symmetry  in  arrangement. 
septal  ends.     Tabulae  completely 
se 


Streptelasma  Hall  (Fig.  107).     Turbinate,  often  curved.     Septa  numerous 


rBCLASS  I 


TETRACORALLA 


83 


10-130),  alternately  long  and  short;  the  free  edges  of  the  longer  septa  are 
'isted  together  in  the  centre  to  form  a  pseudo-columella.  Tabulae  few  er 
)sent.  Position  of  the  cardinal  septum  is  recognisable  on  the  exterior  by  the 
System  of  pinnately  diverging  costal  ridges.  Common  in  Ordovician  and 
Silurian.  S.  pro-  s  a  k 
fundmn  (Owen), 
the  type  species, 
has  often  been 
confused  with  S. 
corniculum  and 
various  species  of 
Zaphrentis. 

Zaphrentis  Raf . 
(Caninia  Mich. 
pars)  (Figs.  108- 
10).  Simple,  tur- 
binate  or  sub- 
cylindrical,  fre- 
quently  elongated. 
Calice  deep,  with 

circular  margin.  Septa  numerous,  reaching  to  the  centre  ;  cardinal  septum  in  a 
deep  fossula.  Tabulae  numerous;  somewhat  irregulär,  and  passing  from  side  to 
side  of  the  visceral  chamber ;  dissepiments  sparingly  developed  in  outer  zone 
of  corallum.  50  to  60  species  known,  ranging  from  Silurian  to  Carboniferous. 
Maximum  development  in  Carboniferous. 

Amplexus  Sow.     Simple,   sub-cylindrical  or   elongated  turbinate.     Calice 


Streptelasma  profundum  (Owen).    Cincinnatian  Group 


(Ordovician);   Cincinnati,  Ohio. 


Side   view. 


B,  Transverse  section,     C,   Longitudinal  section.     (h, 
Cardinal  septum  ;  g,  counter  septum  ;  s,  alar  septum.) 


Fig.  108. 

Zaphrentis  cornlcxda 
Lesueur.  Devonian  lime- 
stone ;  Ohio. 


Fig.  109. 


Zaphrentis  cornucopiae 
Mich.  Calice  enlarged. 
Carboniferous  Limestone ; 
Tournay,  Belgium. 


Fig.  110. 

Zaphrentis  enniskilleni  Nich.  Carboniferous  Lime- 
stone ;  A,  B,  Transverse  sections  through  respectively 
Upper  and  lower  portions  of  calice.  (',  A  long  and  two 
Short  septa  united  at  the  ends  to  form  the  wall.  D, 
Longitudinal  section  showing  tabulae (after  Nicholson). 


shallow,  usually  with  septal  fossulae.  Septa  moderately  numerous,  short, 
never  produced  to  centre.  Tabulae  highly  developed,  horizontal.  Ordovician 
to  Lower  Carboniferous.     Type,  A.  coralloides  Sow. 

Aulacophyllum    E.    and    H.     Turbinate.     Septa   numerous,   extending  to 


84 


COELENTERATA— ANTHOZOA 


PHYLUM  II 


centre.  Cardinal  septum  in  deep  fossula  ;  adjacent  septa  pinnately  developed. 
Ordovician  to  Devonian. 

Menophyllum  E.  and  H.  (Fig.  100).  Turbinate.  Cardinal  septum  in 
largest  of  three  fossulae.     Lower  Carboniferous  limestone. 

Lophophyllum  E.  and  H.  Carboniferous  limestone.  Anisophyllum  E.  and 
H.  Ordovician  to  Devonian.  Pycnophyllum  Lindstr.  Ordovician  and  Silurian. 
Apasmophyllum  Eoem.  Metriophyllum  E.  and  H.  Thamnophyllum  Penecke. 
Devonian.     Penfaphyllum  de  Koninck.     Carboniferous. 


Family  4.     Cyathophyllidae    Milne  Edwards  and  Haime. 


Simple  or  composite  coralla.  Septa  numerous,  radially  arranged ;  the  four 
piincipal  septa  rarely  distinguished  by  greater  or  smaller  size.  Tabulae  and 
vesicular  tissue  (dissepiments)  abundant. 

Cyathophyllum  Goldf.  (Figs.  111-13).  Extremely  variable  in  form, 
sometimes  simple,  turbinate  or  sub-cylindrical ;  sometimes  giving  rise  to 
bushy,  fasciculate  or  astraeiform  colonies,  where  reproduction  takes  place  by 


Fig.  111. 

Cyathophyllum  caespitosum  Goldf. 
Devonian  ;  Gerolstein,  Eifel.  Natural 
size. 


Fig.  112. 

Cyathophyllum  hexagonum   Goldf.    Devonian 
stein,  Eifel.     Natural  size. 


Gerol- 


calicinal  or  lateral  gemmation.  Septa  very  numerous,  strictly  radial  in 
arrangement,  and  of  ten  alternately  long  and  short ;  the  longer  septa  extend- 
ing  to  the  centre.  Visceral  Chamber  filled  with  numerous  imperfectly 
developed  tabulae ;  vesicular  dissepiments  highly  developed  in  peripheral 
portion.  Nearly  100  species  known,  ranging  from  Ordovician  to  the  Lower 
Carboniferous.     Maximxum  development  in  Devonian. 

Campophyllum  E.  and  H.  (Fig.  1 1 4).  Like  the  preceding,  but  septa  not 
extending  to  the  centre.     Devonian  and  Carboniferous  Limestone. 

Heliophyllum  Hall.  Usually  simple  and  turbinate,  more  rarely  forming 
dendroid  colonies.  Septa  numerous,  extending  to  the  centre,  and  thickened 
on  their  sides  by  conspicuous  vertical  ridges  ("  carinae  ").     Devonian. 

Diphyphyllum  Lonsd.  (Fig.  115).     Ordovician  to  Carboniferous.     Pholido- 

lum  Lindstr.    Ordovician  and  Silurian;     Eridophyllum  E.  and  H.     Silurian 


FBCLASS  I 


TETEACORALLA 


85 


I 

^^pd  Devoniaii.     Crepidophyllum  Nich.     Craspedophyllum  Dybowski.    Devonian. 
^Ktoninckophyllum    Nich.     Chonaxis  E,    and    H.     Carboniferous.     Clisiophylhm 
^^Pana.     Silurian  to  Carboniferous. 
^H     Oinphyma  llsiL  (Fig.  116).     Corallum  simple,  conical  or  turbinate ;  theca 

I 


Fig.  113. 

Cyathophyllum  heteropliyllum  E.  and  H.  Middle  De- 
vonian ;  Gerolstein,  Eifel.  A,  Transverse ;  B,  Longi- 
tudinal  section  (after  Nicholson). 


Fig.  114.  , 

Campophyllum  com- 
pressum  Ludw.  Car- 
boniferous Limestone  ; 
Hausdorf,  Silesia.  a, 
Longitudinal ;  b,  Trans- 
verse section. 


Fig.  115. 

Diphyphyllum  con- 
cinnum  Lonsd.  Car- 
boniferous Lime- 
stone ;  Kamensk, 
Ural. 


with  root-like  processes.  Septa  numerous  ;  the  four  principal  septa  in  shallow 
fossulae.  Surface  marked  with  pinnafcely  branching  Striae.  Tabulae  numerous. 
Silurian. 

Chonophyllum  E.  and  H.     Silurian  and  Devonian. 


Fig.  116. 


Oinphyma   subturbinata   B.    and    H.      Silurian    limestone 
Gotland,  Svveden.     a,  Side  view  ;  h,  Calice  from  above. 


Fig.  117. 

Lithostrotion 
martini  E.  and  H. 
Lower  Carbonifer- 
ous ;  Hausdorf, 
Silesia.  Sections 
of  individual 
corallite  (after 
Kunth). 


Ptychophyllum  E.  and  H.  Simple  and  turbinate,  or  composite.  Each 
stock  is  composed  of  funnel-shaped,  invaginated  layers,  representing  calicinal 
buds,  the  marginal  lips  of  which  are  more  or  less  reflected  outwards.  Septa 
numerous  and  strongly  twisted  in  the  centre  to  form  a  pseudo-columella  ;  their 


86 


COELENTERATA— ANTHOZOA 


PHYLUM  II 


peripheral  edges  are  thickened  and  are  fused  with  one  another  so  as  to  form  a 
wall.     Silurian  (P.  patellatum  Schlot,  sp.)  and  Devonian. 

Cyclophyllum  Duncan  and  Thom.     Simple,  cylindro-conical.     Septa  numer- 
ous,  the  longer  ones  forming  a  thick  pseudo-columella  with  enclosed  spongy 

tissue. 

Aulophyllum  E.  and  H. ;  Asjpidophyllum,  Bho- 
dophyllum  Nich.  and  Thoms.,  etc.  Carboniferous. 
Lithostrotion  Llwyd  (Stylaxis  M'Coy ;  Fetalaxis 
E.  and  H.)  (Fig.  117).  Fasciculate  or  astraei- 
form  Stocks  composed  of  prismatic  or  cylindrical 
corallites.  Septa  numerous,  alternately  long 
and  short.  Styliform  columella  in  the  centre. 
Abundant  in  Carboniferous  limestone. 


Fig.  118. 

Lonsdaleia  floriformis  Lonsd.  Car- 
boniferons  Limestone ;  Kildare,  Ire- 
land.  i/i.  a,  Two  cylindrical  corallites, 
partially  splitopen  ;  h,  Twohexagonal 
calices,  seen  from  above. 


Fig.  119. 

Phillipsastrea  hennaM  (Lonsdale).     Devonian  limestone ;  Ebersdorf, 
Silesia.    a,  Upper  surface  ;  h,  Transverse  section.     Natural  size. 


Lonsdaleia  M'Coy  (Fig.  118).  Fasciculate  or  astraeiform,  composite 
coralla.  Septa  well  developed  ;  columella  large,  composed  of  vertically  rolled 
lamellae.  Central  tabulate  area  bounded  by  an  interior  dissepimental  wall, 
between  which  and  the  theca  vesicular  endotheca  is  abundantly  developed. 
Common  in  Carboniferous  rocks. 

Strombodes  Schweigg.  Astraeiform  Stocks  composed  of  small  prismatic 
corallites.     Septa  extremely  numerous,  very  slender,  extending  to  the  centre. 


Fig.  120. 

Stauria  astraeiformis  E.  and  H.  Silurian  ;  Gotland,  Sweden.  A,  Transverse  section  parallel  to  upper 
aurface.  B,  Enlarged  transversa  section  of  individual  corallite.  C,  Several  calices  from  above.  Natural  size 
(after  Nicholson). 


Theca  imperfectly  developed.     Visceral  Chamber  filled  with  infundibuliform 
tabulae  and  vesicular  tissue.     Silurian  (S.  typus  M'Coy  sp.)  and  Devonian. 

Fachyphyllum,  Spongophyllum  E.  and  H.     Silurian  and  Devonian. 

Acervularia  Schweigg.     Astraeiform  or  bushy  colonies.       Septa  stout  and 


SUBCLASS  I 


TETRACORALLA 


87 


(lumerous.  An  iiiterior  wall  is  present ;  tabulae  are  developed  in  the  central 
;irea,  while  the  peripheral  zone  is  filled  with  vesicular  tissue,  Silurian  (A. 
(Dianas  Linn.  sp.)  and  Devonian. 

PhiUipsastrea  d'Orbigny  (Fig.  119).  Astraeiform  colonies,  with  indi- 
vidual  corallites  united  by  confluent  septa,  which  are  produced  beyond  the 
theca,  and  obscure  the  same.  Interseptal  loculi  filled  with  vesicular  endotheca. 
Devonian  and  Carboniferous.     Type,  P.  hennahi  (Lonsd.). 

Stauria  E.  and  H.  (Fig.  120).  Astraeiform  or  bushy  composite  coralla. 
Septa  well  developed;  the  four  principal  septa  characterised  by  larger  size,  and 
forming  a  complete  cross  in  the  centre  of  each  corallite.     Silurian  (Wenlock). 

Columnaria  Goldf.  (Favistella  Hall).  Astraeiform  Stocks,  composed  of 
long,  polygonal,  thick-walled  corallites.  Septa  radially  arranged  in  two  cycles, 
alternately  long  and  short,  barely  reaching  the  centre.  Tabulae  horizontal, 
disposed  at  regulär  intervals  apart,  and  stretching  across  the  entire  visceral 
Chamber.  Dissepiments  imperfectly  developed  or  absent.  Ordovician  to 
Devonian. 

Ileterophyllia  M'Coy.     Carboniferous.     Batiersbyia  E.  and  H.     Devonian. 


Family  5.     Oystiphyllidae    Milne  Edwards  and  Hainie. 

Usually  simple  coralla.  Septa  very  thin  ;  interseptal  loculi  filled  with  vesicular 
endotheca  or  compact  stereoplasma.  Tabulae  absent ;  central  area  of  visceral  Chamber 
either  completely  filled  with  vesi- 
cular tissue  or  stereoplasma,  or 
containing  the  same  only  in  the 
lower  portions  of  Chamber.  Cal- 
careous  operculum  sometim,es 
present. 

Cystiphyllum  Lonsd.  (Figs. 
121,  122).  Simple,  very  rarely 
forming  bushy  colonies.  Calice 
deep;  the  entire  visceral  Cham- 
ber filled  with  vesicular  tissue, 
which,  as  a  rule,  wholly 
obliterates  the  numerous  radi- 
ally directed  septa.  Silurian 
and  Devonian. 

Strephodes  M'Coy  (Fig. 
123).  Usually  simple  coralla. 
Septa  well  developed,  alter- 
nately long  and  short,  some- 
times  forming  a  pseudo- 
columella.  Silurian  to  Carbo- 
niferous. 

Goniophyllum  E.  and  H. 
(Fig.  124).  Corallum  simple,  in  the  form  of  a  four-sided  pyramid,  and 
covered  with  thick  epithecal  tissue.  Calice  deep ;  septa  numerous,  thick 
and  very  short.  Entire  visceral  Chamber  filled  with  vesicular  and  stereo- 
plasmic  endotheca.  Operculum  composed  of  four  plates  symmetrically 
paired.     Silurian. 


Fig.  121. 


Fig.  122. 


Cystiphyllum  cylindricum 

Lonsd.     Silurian  ;  Iron  Bridge, 

Cystiphyllum       vesiculosum     England.       A,    B,    Transverse 

Goldf.        Devonian ;      Eifel.     and  longitudinal  sections  (after 

Natural  size.  Nicholson). 


88 


COELENTERATA—ANTHOZOA 


PHYLUM  II 


Bhizophyllum  Lindst.  Corallum  simple,  pyramidal  or  hemispherical, 
flattened  on  one  side  ;  external  surface  corrugated,  and  sending  ofF  hollow, 
root-like  epithecal  processes.  Calice  marked  with  septal  Striae ;  internal 
structure  consisting  of  vesicular  tissue  and  stereoplasma.  Operculum  in  form 
of  semicircular  plate  ;  inner  surface  traversed  by  median  ridge  and  fainter, 
granulated,  parallel  elevations.     Silurian. 

Calceola  Lam.  (Fig.  125).    Corallum  simple,  semi-turbinate,  or  slipper-shaped, 


Fio.  123. 

Strephodes  mnrchisoni  Lonsd. 
Showing  strongly  developed 
dissepiments  and  tabulae. 


Fk..  124. 

Goniophyllum     pyramidale 
(His.).       Silurian ;    Gotland. 

A ,  Specimen  with  operculum. 

B,  Calice  seen  from  above. 
Natural  size  (after  Lind- 
ström). 


Calceola 
Devonian ; 


Fig.  125. 

sandalina     Lam. 
Eifel.       Natural 


with  one  side  flat  and  triangulär.  Calice  very  deep,  extending  nearly  to  apex, 
and  marked  internally  with  fine  septal  Striae.  Cardinal  septum  placed  in  the 
centre  of  the  vaulted  side,  counter  septum  in  middle  of  flattened  side,  and  alar 
septa  at  the  angles.  Internal  structure  composed  of  fine  vesicular  tissue  and 
Stereoplasma.  Operculum  semicircular,  very  thick,  under  surface  marked  with 
prominent  median  and  fainter  lateral  septal  ridges.  C.  sandalina  Lam.  Very 
common  in  Middle  Devonian  of  Europe,  rare  in  Carboniferous  Limestone  of 
Belgium. 

Range  and  Distribution  of  the  Tetracoralla. 

The  typical  Tetracoralla  are  confined  to  the  Paleozoic  rocks.  They  are 
unknown  in  the  Cambrian,  and  make  their  first  appearance  in  the  Ordovician, 
where  they  are  sparsely  represented  in  North  America  and  in  Europe.  Here 
the  most  abundant  genus  is  Streptelasma,  and  next  in  order  of  importance  are 
Cyathophyllum,  Ftychophyllum  and  Columnaria.  The  maximum  development 
falls  in  the  Silurian,  which  contains  the  largest  number  of  genera  and  species. 
There  are  limestones  found  on  the  Islands  of  Gotland  and  Dago  (Esthonia),  as 
well  as  at  Dudley,  Shropshire,  at  Lockport,  New  York  and  other  places  in 
North  America,  which  are  made  up  of  ancient  coral-reef s.  The  principal  agents 
concerned  in  the  formation  of  these  reefs  were  Cyathophyllum,  Heliophyllum, 
Omphyma,  Ptychophyllum,  Sfromhodes,  Acervularia,  Stauria,  Aulacophyllum,  Cysti- 
phyllum,  etc.,   of  the  Tetracoralla,   besides  numerous  Tabulata,   Octocoralla, 


süBCLÄSS  II  HEXACORALLA  89 

Bryozoa,  and  Echinoderms.  The  Tetracoralla  are  not  less  conspicuous  in  the 
Devonian,  especially  in  the  Middle  and  Upper  Devonian  of  the  Eifel  district, 
Westphalia,  Nassau,  Harz,  Boulogne,  England,  and  North  America.  ■-  Particu- 
larly  abundant  here  are  the  genera  Cyathophyllum,  Campophyllum,  Zaphrentis, 
Cystiphyllum,  Phülipsasti'ea,  Calceola,  etc.  Zaphrentis,  Amplexus,  Lithostrotion, 
Lonsdaleia,  Cyclophyllum^  etc.,  predominate  in  the  Carboniferous  Limestone  of 
Belgium,  England,  Ireland,  and  North  America ;  while  in  the  Zechstein  the 
solitary  genus  known  is  Polycoelia.  On  the  other  band,  the  Permo-Carboni- 
ferous  rocks  of  the  Salt  Range  in  India  and  of  the  island  of  Timor  contain  the 
genera  Zaphrentis,  Amplexus,  Clisiophyllum,  and  Lonsdaleia.  According  to  Frech, 
the  genera  Gigantostylis,  Piriacophyllum,  and  Coccophyllum,  occurring  in  the  Alpine 
Trias,  belong  to  the  Tetracoralla ;  and  to  this  group  also  have  been  assigned 
Holocystis  E.  and  H.,  from  the  Cretaceous,  and  the  recent  genera  Haplophyllum 
Pourtales,  and  Guynia  Duncan.  A  number  of  Paleozoic  Tetracoralla,  such  as 
Baitersbyia,  Heterophyllia,  and  Stauria,  are  referred  by  Duncan  and  Nicholson  to 
the  Hexacoralla  (^'  Astraeidae"). 


Subclass  2.    HEXACORALLA   Haeckel. 

(Zoantharia  Blainville  ;  Hexadinia  and  Polyadinia  Ehrenberg.) 

Simple  or  composite  polyps,  with  radial  mesenferies  arising  in  cydes  of  six,  iwelve, 
or  multiples  of  six  (more  rarely  pentameral,  septameral  or  odameral) ;  frequently  with 
calcareous  corallum,  hut  sometimes  fleshy  or  with  hoo'ny  axis. 

To  the  Hexacoralla  belong  the  calcareous  reef-building  and  deep-sea  corals 
(Madreporaria)  of  the  present  day,  the  fleshy  sea-anemones  (Adiniaria),  and 
those  forms  characterised  by  the  secretion  of  a  horny  axis  (Antipatharia).  Of 
these  three  Orders,  only  the  Madreporaria  are  known  in  a  fossil  State.  These 
forms  are  distinguished  from  the  Tetracoralla  by  the  hexameral  System  and 
radial  arrangement  of  mesenteries  and  septa ;  and  from  the  Octocoralla,  in 
addition  to  the  above-named  characters,  by  their  simple  tentacles. 

According  to  Duerden,  either  before  or  shortly  after  extrusion  of  the 
larva,  the  six  primary  pairs  of  mesenteries  (protocnemes),  constituting  the  first 
cycle,  make  their  appearance.  The  organs  arise  in  bilateral  pairs,  in  a 
regulär  and  well-defined  order,  which  is  uniform  for  all  the  species  yet 
studied.  The  first  two  or  three  pairs  arise  around  the  oral  extremity  of  the 
larva,  while  the  others  first  appear  at  varying  distances  down  the  wall.  The 
protocnemic  sequence  is  represented  by  the  Roman  numerals  in  Fig.  126,  and 
agrees  with  that  established  for  the  greater  number  of  actinians.  The  first 
four  pairs  very  early  unite  with  the  stomodaeum,  but  the  fifth  and  sixth 
pairs  remain  free  or  incomplete  for  a  lengthened  period,  suggesting  a  diflferent 
phylogenetic  significance  from  the  others. 

The  six  pairs  of  second  cycle  mesenteries  (metacnemes)  arise  after  fixation, 
but  in  a  manner  altogether  difFerent  from  that  followed  by  the  first  cycle. 
They  appear  on  the  polypal  wall  in  unilateral  pairs  or  couples  within  the 
six  primary  exocoeles,  and  in  a  succession  which  is  from  the  dorsal  to  the 
ventral  side  of  the  polyp,  not  the  whole  cycle  at  a  time.  For  a  long  time, 
as  shown  in  Fig.  127,  the  six  pairs  present  a  diff"erence  in  size,  corresponding 
with  their  dorso-ventral  or  antero-posterior  order  of  appearance. 


90 


COELENTERATA— ANTHOZOA 


PHYLÜM  II 


The  twelve  pairs  of  third  cycle  mesenteiies  are  found  to  develop  in  a 
succession  fwhich  is  altogether  unexpected.  They  follow  the  same  dorso- 
ventral  order  as  the  second  cycle  pairs,  but  in  two  series.  A  primary  series 
of  six  pairs — one  pair  within  each  sextant — appears  within  the  exocoele  on 
the  dorsal  aspect  of  each  of  the  second  cycle  mesenteries,  one  pair  following 
upon  another,  and  then  another  series  of  six  pairs  arises  on  the  ventral 
aspect  of  the  second  cycle  mesenteries  in  the  same  order  (Fig.  128).  In  the 
later  stages  of  development  the  regularity  of  the  mesenterial  succession  is  not 


IZ 


IE 


w 


JS. 


m 


m 


Fig.  126. 


Growth  stages  of  coral  polyp  in  Maeandra  ("  Manicina")  areolata.  Diagrammatic  flgures  showing  order  of 
appearance  of  the  six  primary  pairs  of  mesenteries.  In  a  only  two  pairs  of  mesenteries  are  present,  of  which  one 
pair  (i)  is  imited  with  the  stomodaeum,  while  the  other  (ii)  is  free  ;  in  b  the  second  pair  of  mesenteries  has  become 
complete,  and  a  third  pair  (iii)  has  appeared  on  tlie  ventral  border  ;  in  c  another  pair  (iv)  is  found  within  the  dorsal 
Chamber ;  in  d  the  first  four  pairs  of  mesenteries  to  arise  have  all  become  complete,  and  the  fifth  and  sixth 
pairs  (v,  vi)  have  appeared,  but  remain  incomplete  for  a  long  period,  the  secondary  mesenteries  appearing  in 
the  meantime  (cf.  Fig.  127).  The  actual  stages  given  are  taken  from  Maeandra  areolata,  but  a  like  sequence  is 
presented  by  other  species  whose  development  has  been  foUowed  (after  Duerden). 


always  maintained  ;  one  region  may  be  somewhat  in  advance  of,  or  may  lag 
behind  its  normal  development. 

The  sequence  thus  outlined  in  the  briefest  manner  is  sufficient  to  show 
that  the  development  of  the  mesenteries  in  coral  polyps  is  bilateral,  and 
takes  place  in  stages  from  one  extremity  to  the  other.  The  radial  symmetry, 
characteristic  of  the  adult  polyp,  is  thus  derived  from  primitively  bilateral 
Organs,  which  appear  in  an  antero-posterior  succession.  Moreover,  each  cycle 
represents  a  separate  period  of  development,  as  compared  with  the  successive 
growth  in  one  direction  of  ordinary  segmented  animals. 

The  first  two  cycles  of  tentacles  (prototentacles)  generally  arise  a  cycle  at 
a  time,  either  simultaneously  or  one  following  the  other.     The  later  tentacles 


SlinCLASS  II 


HEXACORALLA 


91 


are  developed  in  an  order  in  correlation  with  that  of  the  mesenteries,  some- 
times  entocoelic  and  exocoelic  members  appearing  together.  In  the  process 
of  growth  the  exocoelic  members  are  always  relegated  to  the  outermost 
cycles,  in  a  manner  first  established  by  Lacaze-Duthiers  for  actinians ;  only 
the  entocoelic  tentacles  are  of  any  ordinary  value,  Siderastrea  radians  (Pallas) 
is  exceptional  in  that  the  exocoelic  tentacles  appear  in  advance  of  the 
entocoelic. 


Fig.  127. 

Growth  stages  of  larval  polyps  in  Siderastrea  radians.  Three  diagramrnatic  figures  illustrating  the  manner 
of  appearance  of  the  six  mesenteries  (A-C)  constituting  the  second  cycle.  The  mesenteries  arise  in  unilateral 
pairs  witliiii  corresponding  exocoelie  Chambers  on  each  side  of  the  polyp.  At  first  (a)  a  ])air  appears  within  the 
dorso-lateral  exocoele  on  each  side  ;  shortly  after  (li)  a  similar  pair  arises  within  each  middle  exocoele ;  then  (c) 
a  pair  within  each  ventro-lateral  exocoele.  For  a  long  time  the  pairs  retain  a  diö'erence  in  size,  corresponding 
with  their  order  of  appearance  (after  Duerden). 

The  skeleton  never  appears  until  after  fixation  of  the  larva.  It  makes  its 
first  appearance  in  the  form  of  minute  plates  or  granules,  as  an  ectoplastic  pro- 
duct  of  the  ectodermal  cells  (calicoblasts)  of  the  base.  A  flat,  circular,  basal 
plate  is  formed  by  the  union  of  these,  and  may  later  become  produced  upward 
at  the  edge  as  the  epitheca,  while  from  its  inner  or  polypal  surface  the  septa 
begin  to  appear  as  vertical  upgrowths  formed  within  invaginations  of  the 
basal  disk  of  the  polyp.  The  skeletal  cup  first  formed  is  known  as  the 
prototheca. 


92 


COEliENTERATA— ANTHOZOA 


PHYLUM  II 


Like  the  tentacles,  the  first  two  cycles  of  septa  (protosepta)  may  appear 
simultaneously,  or  the  cycle  of  six  entosepta  may  arise  in  advance  of  the 
cycle  of  six  exosepta.  The  order  of  appearance  of  the  later  cycles  is  not  yet 
thoroughly  understood,  the  relative  sizes  in  the  mature  corallum  by  no  means 
indicating  the  actual  order  of  developnient.  As  in  the  case  of  the  mesenteries, 
the  radial  plan  of  the  mature  septa  is  derived  from  structures  which  appear 
bilaterally,   in   a   more    or    less    definite   dorso  -  ventral    or    antero  -  posterior 


Fig.  128. 

Three  stages  in  the  development  of  the  twelve  pairs  of  third-cycle  mesenteries.  All  the  six  pairs  of  primary 
mesenteries  are  now  complete,  and  the  second-cycle  pairs  are  all  equal,  but  free  from  the  stoniodaevnn.  In  a  a 
pair  of  third-cycle  mesenteries  (iii)  has  appeared  on  each  side,  within  the  exocoele  next  the  dorsal  directives  ;  in 
b  a  corresponding  pair  occurs  within  the  dorsal  of  the  two  exocoeles  of  all  the  six  Systems,  the  order  being  from 
the  dorsal  to  the  ventral  aspect ;  in  c  another  series  of  six  pairs  is  beginning,  situated  within  the  ventral  of  the 
two  exocoeles  in  each  system.    Growth  in  the  dorsai  region  is  in  advance  of  that  in  the  ventral  (after  Duerden). 


succession.  Furthermore,  as  in  the  case  of  the  tentacles,  the  exosepta  remain 
exosepta  throughout  the  course  of  their  development,  always  constituting  the 
outermost  cycle.  The  entosepta  beyond  the  primary  six  follow  the  same 
succession  of  growth  as  the  mesenteries,  so  that  the  order  assigned  the 
secondary  and  tertiary  mesenteries  in  Fig.  129  will  also  hold  for  the  septa. 
Eeproduction  takes  place  either  sexually,  when  separate  individuals  are  pro- 
duced ;  or  asexually,  by  means  of  lateral  or  basal  gemmation ;  or  by  fission. 
In   composite   coralla,  the  individual   corallites  are   sometimes  united  by   a 


suBCLASs  II  HEXACORALLA  93 

common  coenenchyma.     Endothecal  structures  are  frequently  present  in  the 
form  of  synapticulae,  dissepiraents,  and  tabulae. 

The  Order  of  stone  corals  or  Madreporaria  {Zoantharia  sclerodermata)  was 
divided  by  Milne  Edwards  and  Haime  into  five  suborders  :  Eugosa,  Tahulata, 
Tuhulosa,  Perforata,  and  Aporosa.  Of  these,  the  Eugosa  have  been  elevated  by 
Haeckel  into  a  separate  subclass  under  the  name  of  Tetracoralla.  The  groups 
Aporosa  and    Perforata   are    called   Hexacoralla ;    while   the   afiinities   of    the 


Fig.  129. 

Diagram  showing  the  Order  of  appearance  of  all  the  mesenteries  in  a  polyp  having  three  cycles.  The  Roman 
numerals  represent  the  cycles  to  which  the  mesenteries  belong,  and  the  smaller  Arabic  numerals  indicate  the 
Order  in  which  the  mesentery  appeared  within  its  cycle.  The  regularity  here  indicated  Is  constant  for  the 
primary  and  secondary  cycles,  but  departure  may  be  encountered  in  the  third  cycle  (after  Duerden). 

Tahulata  (with  which  the  Tuhulosa  are  now  generally  included)  are  still 
unsatisfactorily  determined.  The  group  is  certainly  composed  of  a  varied 
assemblage  of  forms,  some  of  which  have  been  assigned  to  the  Hexacoralla, 
some  to  the  Octocoralla,  and  some  to  the  Hydrozoa  and  Bryozoa. 

Order  1.     MADREPORARIA   Milne  Edwards.  ^ 

(Zoantharia  sclerodermata  E.  and  H.) 

Eadially   symmetrical   sclerodermous   corals  with   typically    hexameral   (rarely 
pentameral,  heptameral,  or  octameral)  arrangement  of  septa. 

^  Literature  :  Pratz,  E. ,  Ueber  die  verwandtschaftliche  Beziehungen  einiger  Korallengattungeu, 
etc.  Palaeontogr.  1882,  vol.  xxix. — Frech,  F., Die  Korallenfauna  der  Nordalpinen  Trias.  Palaeontogr. 
1890,  vol.  xxxvii. — British  Museum  Cat.  of  Madreporarian  Corals,  vol.  i.  by  George  Brook,  1893, 
vols.  ii.-vi.  by  //.  M.  Bernard,  1896-1906.— Volz,  W.,  Die  Korallen  der  Schichten  von  St. 
Cassian  in  Süd-Tirol.  Palaeontogr.  1896,  vol.  xliii.  Felix,  J.,  Anthozoen  der  Gosauschichten 
in  den  Ostalpen.  Palaeontogr.  1903,  vol.  xlix. — Duerden,  J.  E.,  The  Coral  Siderastrea,  etc. 
Carnegie  Inst.  Wash.,  1903,  Pub.  No.  20.— Lang,  W.  D.,  Growth-Stages  in  the  Coral  Genus  Para- 
smilia.  Proc.  Zool.  Soc.  London,  1909,  pt.  ii. — Paroim,  G.  F.,  La  Fauna  coralligena  del  Cretaceo 
dei  Monti  d'  Ocre  nell'  Abruzzo.     Mem.  Com.  Geol.  Ital.,  1909,  vol.  v.     (See  also  ante,  p.  74). 


94 


COELENTERATA— ANTHOZOA 


PHYLÜM  II 


Suborder  1.     APOROSA  Milne  Edwards  and  Haime. 

Septa  and  theca  compact;  interseptal  loculi  usually  partitioned  off  hy  dissepi- 
ments  or  synapticulae,  more  rarely  hy  tabulae,  seldom  empty  throughout.      Theca 


either  independenÜy  secreted,  or  formed  hy  fusion  of  the  septal 


or  ahsent. 


Family  1.     Turbinolidae  Milne  Edwards  and  Haime. 

Corallum  simple,  very  seldom  composite ;  septa  numerous,  long,  and  with  entire 
margins.  Interseptal  loculi  empty  throughout.  Columella  usually,  pali  often  present. 
Theca  comi 


The  Turhinolidae  begin  in  the  Jurassic,  and  are  especially  abundant  in  the 
Tertiary  and  at  the  present  day.  Sexual  reproduction  prevails, 
although  a  few  forms  multiply  by  gemmation ;  the  buds,  how- 
ever,  become  separated  from  the  parent  animal  at  an  early 
period. 

Turhinolia  Lam.  (Fig.   130).     Corallum  free,  conical,  with 
circular  calice.     Septa  produced  beyond  the  theca.     Styliform 


Fig.  130. 

Turhinolia  bowei-- 
lanJci  E.  and  H. 
Eocene ;  Highgate, 
England.    6/^. 


Fig.  131. 

Ceratotroclius  duodecimocostatus  (Goldf.).     Miocene 

Baden,  near  Vienna.     Natural  size. 


Fig.  132. 

Fläbelhim  roissyanum  E. 
and  H.  Miocene;  Baden, 
near  Vienna.    Natural  size. 


columella  present.  Tertiary  and  Recent ;  common  in  Calcaire  Grossier  of 
the  Paris  Basin,  and  Eocene  of  England  and  southern  United  States. 

Sphenotrochus  E.  and  H.  Free,  cuneiform  with  elongated  calice;  colum- 
ella lamellar.  Cretaceous  to  Recent.  Type,  S.  crispus  (Lam.).  Eocene  to 
Recent.  Common  in  Calcaire  Grossier  of  the  Paris  Basin,  and  in  the  Eocene 
of  the  Gulf  States. 

Smilotrochus  E.  and  H.;  Stylotrochus  From.;  Onchotrochus  Duncan.  Cre- 
taceous.    Discotrochus  E.  and  H.  etc.     Tertiary. 

Ceratotrochus  E.  and  H.  (Fig.  131).  Horn-shaped  ;  young  forms  attached 
at  the  apex.  Septa  very  numerous,  produced  above  the  theca;  columella 
fasciculate.     Cretaceous  to  Recent. 

Flahellum  Lesson  (Fig.  132).  Corallum  wedge-shaped,  compressed,  free, 
or  attached.  Septa  numerous.  Wall  covered  with  epitheca,  and  sometimes 
furnished  with  spinous  processes.     Tertiary  and  Recent. 

Trochocyathus  E.  and  H.  (Fig.  133).  Horn-shaped,  with  circular  calice. 
Septa  stout ;  columella  papillous  and  trabecular,  and  surrounded  by  several 
cycles  of  pali.     Numerous  species  from  Lias  to  Recent. 


;übclass  II 


HEXACORALLA 


95 


Thecocyathus  E.  and  H.     Depressed,  conical,  or  discoidal,  attached  early  in 
life,  later  becoming  free.      Wall   with  thick  epithecal  Investment.      Calice 
circular,  septa  numerous ;  columella  fasciculate,  and  sur- 
rounded  by  several  cycles  of  pali.     Lias,  Jurassic,  Cre- 
taceous,  and  Recent. 

Paracyathus,  Deltocyathus  E.  and  H.  (Fig.  134). 
Tertiary  and  Recent.  Discocyathus  E.  and  H.  Jurassic. 
Coenocyathus,  Acanthocyathus,  JBathycyathus  E.  and  H.,  etc. 
Tertiary  and  Recent. 

Caryophyllia  Lam.  (Fig.  135).     Turbinate,  with  broad 


Fig.  133. 


Fig.  134. 


Trochocyathiis  conulus  From.     Aptian  ;        Deltocyathus  italicus  E.  and  H.  Miocene ; 


Fio.  135. 

Caryophyllia     cyathus 
Sol.  Recent.  Lougitudi- 


Haute  Marne,     a,  Profile,  natural  size  ;  h,    Porzteich,    Moravia. 


Calice  enlarged. 


size  ;  b,  Calice  enlarged. 


Profile,  natural    nal  section,  natural  size 
(after  Milne  Edwards). 


base,  attached.     Calice,    circular ;    columella   papillous,  trabecular,  and   sur- 
rounded  by  a  single  cycle  of  pali.     Cretaceous  to  Recent. 


Family  2.     Oculinidae  Milne  Edwards  and  Haime. 

Invariably  composite  coralla,  increasing  by  lateral  gemmation.  Walls  of  corallites 
thickened  by  a  compact  coenenchyma.  Lower  portion  of  visceral  Chamber  narrowed  or 
filled  up  by  deposition  of  stereoplasma.  Septa  moderately  numerous  ;  interseptal  loculi 
usually  open  to  the  base.    Lias  to  Recent ;  fossil  forms  not  particularly  numerous, 

Oculina  Lam.  Corallites  irregularly  or  spirally  distributed  over  the  smooth 
surface  of  coenenchyma.  Septa  slightly  projecting ;  columella  papillous, 
surrounded  by  cycle  of  pali.     Tertiary  and  Recent. 

Agathelia  Reuss.  Like  the  preceding,  but  form- 
ing  tuberous  or  lobate  colonies.  Cretaceous  and 
Tertiary. 

Synhelia  E.  and  H.  Cretaceous.  Astrohelia  E. 
and  H.  Tertiary.  Psammohelia,  Euhelia  E.  and  H., 
etc.     Jurassic. 

Ilaplohelia  Reuss.  Small,  arborescent,  with 
corallites  all  disposed  on  one  side  of  the  branches. 
Coenenchyma  striated  or  granulated.  Septa  in 
three  cycles  ;  columella  and  pali  present.    Oligocene. 

Enallhelia  E.  and  H.  (Fig.  136).  Stock  branch- 
ing ;  corallites  disposed  usually  in  alternating 
sequence  in  two  rows  along  the  sides  of  branches. 

Coenenchyma    highly    developed,    striated,    or    granulated;    columella    rudi- 
mentary.     Jurassic.     Type,  E,  Compressa  (d'Orb.). 


Fig.  136. 

Enallhelia  striata  Quenst.  Coral- 
Rag  ;  Nattheim.  a,  Natural  size  ; 
b,  Calice  enlarged. 


96 


COELENTERATA— ANTHOZOA 


PHYLUM  ir 


Family  3.     Pocilloporidae   Verrill. 

Composite,  branchirig,  lohate,  or  massive  colonies,  with  small  cylindrical  corallites, 
united  hy  compact  coenenchyma.  Sepfafew  (6-24),  sometimes  rudimentary.  Visceral 
Chamber  partitioned  off  by  horizontal  tabulae. 

Of  the  two  Recerit  genera  belonging  to  this  family,  Pocillopora  and  Seriato- 
pora  Lam.,  the  former  occurs  also  in  the  Miocene  of  the  West  Indies. 


Family  4.     Stylophoridae    Milne  Edwards  and  Haime. 

Composüe  coralla,  with  corallites  united  by  vesicular  or  compact  coenenchyma. 
f^  1,  Septa  well  developed  ;  a  prominent,  styli- 

form  central  columella;  interseptal  loculi 
empty  throughout.  Jurassic  to  Eecent. 
Stylophora  Schweigg.  (Fig.  137). 
Stock  branching,  or  depressed, 
massive     and     tuberous.         Calices 


small. 


Fig.  137. 
Stylophora  subreticulata  Reuss.     Miocene  ;  Grund,  near 
Vienna.    a,   Corallum,  natural  size;  b,  surface   greatly 
enlarged. 


Araeacis  E.  and  H.     Eocene. 


embedded      in 

spinous,  coenenchyma. 

developed,    moderately 

columella       styliform. 

Tertiary,  and  Recent. 

Stylohelia  From.     Jurassic  ;  Europe. 


abundant, 


Septa   well 

numerous  ; 

Jurassic, 


Family  5.     Astraeidae  i    Milne  Edwards  and  Haime. 

Corallum  composite,  or  more  rarely  simple.  Theca  formed  by  fusion  of  sepfal 
edges.  Septa  numerous,  usually  well  developed,  upper  edges  toothed,  serrated,  or 
lobular ;  visceral  Chamber  partitioned  off  by  more  or  less  abundantly  developed 
dissepiments,  more  rarely  by  tabulae.  Multiplication  by  budding  or  fission.  Corallites 
of  massive  colonies  usually  reaching  considerable  altitude,  and  united  with  one  another 
either  directly  by  the  walls  or  by  means  of  septa  exothecally  produced  (costal  septa). 

Very  abundant  from  thß  Trias  onwards,  and  by  far  the  most  protean  family 
of  all  the  Hexacoralla.  According  to  the  serrated  or  entire  character  of  the 
free  septal  edges,  Milne  Edwards  and  Haime  divided  their  Astraeidae  into  two 
subf amilies — the  Astraeinae  and  the  Eusmiliinae,  the  latter  of  which  has  been 
elevated  by  Yerrill  to  family  rank. 

a.  Simple  coralla. 

Montlivaltia  Lamx.  (Fig.  138).  Cylindrical,  conical,  turbinate,  or  dis- 
coidal,  and  either  acutely  pointed,  or  broadly  expanded  at  the  base.  Septa 
numerous,  upper  edges  serrated.     Columella  absent ;  epitheca  thick,  corrugated, 

^  The  family  name  Astraeidae  is  not  available  for  use  among  corals,  as  the  generic  name  Astraea 
was  applied  by  Bolten  in  1798  to  mollusks  now  referred  to  T^i7'bo  and  Xenophora,  three  years 
previous  to  its  application,  in  1801,  by  Lamarck  to  corals.  It  is  known  that  the  Astraeidae  of 
Milne  Edwards  and  Haime  does  not  represent  a  natural  association  of  corals,  and,  therefore,  must 
be  dismembered  and  divided  into  a  number  of  families.  Several  subdivisions  have  already  been 
proposed,  but  the  detailed  investigation  of  all  the  constituent  genera  has  not  progressed  far  enough 
to  determine  their  natural  affinities  in  all  cases.  In  view  of  this  condition  it  seems  better  to 
continue  temporarily  the  use  of  the  term  Astraeidae  until  all  the  corals  included  under  it  have  been 
thoroughly  studied  and  their  systematic  affinities  ascertained  than  to  propose  a  Substitute  name 
for  one  known  to  be  invalid. 


.SUBCLASS  II 


HEXACORALLA 


1)7 


readily  becoming  detached.  Common  in  Triassic  and  Jurassic  ;  somewhat  rare 
in  Cretaceous  and  Tertiary.  The  genus  should  probably  be  made  to  include 
various  species  which  have  been  referred  to  Epismilia  From.,  and  the  so-called 
Oppelismilia  Duncan. 

ß.  Simple  cor a  IIa  or  composite  coJonies 
iiiiiUiphjing  hy  calicinal  or  marginal  gem- 
ination. 

Sfijlophyllum  Eeuss.  Corallum  simple, 
either  with  or  without  calicinal  or 
marginal  gemmation,  or  f orming  massive 
colonies.  Septa  stout,  but  only  in- 
feriorly  complete,  terminating  above  in 

strong  vertical  spines.  Dissepiments  vesicular ;  wall  covered  with  epitheca. 
Alpine  Trias. 

Stylophyllopsis  Frech.     Simple  or  imperf.ectly  branching.     Septa  terminating 
near  the  centre  in  detached  vertical  spines.     Alpine  Trias. 


Fifi.  138. 

MontltvdUia  caryophyllata  (Lamx.).     Great  Oolite  : 
Caen,  Calvados.     Natural  size. 


Stylocora  exilis  Reuss.  Mio- 
ccne  ;  Niederleis,  Austria.  a, 
Corallum  in  natural  size.  h, 
Calice  enlarged  (after  Reuss). 


Bushy  colonies  multiplying  hy  lateral  gemmation. 

Cladocora  Ehrbg.  Corallum  composed  of  long 
cylindrical  branches,  free  on  all  sides.  Calice  circular  ; 
septa  well  developed ;  columella  papillous  ;  cycle  of 
pali  present.     Jurassic  to  Recent. 

Stylocora  Reuss  (Fig.  139).  Branches  cylindrical; 
septa  stout,  those  of  the  first  cycle  with  columnar 
thickenings  or  inner  edges ;  columella  styliform. 
Cretaceous  and  Miocene. 

Pleürocora  E.  and  H.  Cretaceous.  Goniocora  E. 
and  H.     Triassic  and  Jurassic. 


h.   Composite  corallites  multiplying  hy  hasal  gemmation  ;  huds  arising  from  stolons 

or  hasal  expansions. 

Rhizangia  E.  and  H.  (Fig.  140).     Corallites  united  by  short,  sub-cylindrical 


Fig.  140. 

Rhizangia michclini Reuss.  Middle 
Cretaceous  ;  Gosau  Valley,  Austria. 
Natural  size  (after  Reuss). 


Fio,  141. 

Viadang iaconferki  Reuss.  Miocene;  Bischofs- 
wart,  Moravia.  a,  Corallum,  natural  size ;  b, 
Calice  enlarged  (after  Reuss). 


Stolons.   Calices  shallow,  circular;  columella  papillous.  Cretaceous  and  Tertiary. 
Latusastrea  d'Orbigny.     Corallites  arising  from  common  basal  expansion, 
Short  and  strongly  inclined  to  one  side,  so  that  the  calices  acquire  a  semi- 
VOL.  I  H 


98 


COELENTERATA— ANTHOZOA 


PHYLUM  II 


circular    contour   and    assume    the    form    of    protruded    lips.      Jurassic   and 
Cretaceous. 

Astrangia,  Cryptangia,  PhyUangia,  Cladangia  (Fig.  141),  Ulangia  E.  and  H., 
etc.     Tertiary  and  Recent. 

€.  Massive  coralla  muUiplying  hy  lateral  gemmation. 

Orbicella  Dana  (Fig.  142).  Cylindrical  corallites  united  by  exothecally 
produced,  confluent,  costal  septa.  Columella  spongy ;  dissepiments  numerous 
between  the  septa  both.  within  and  exterior  to  the  theca.     Jurassic  to  Recent. 

Plesiastraea  From.  Like  the  preceding,  but  with  several  pali  in  front  of 
all  the  cycles  excepting  the  last.      Tertiary  and  Recent. 


Fig.  143. 

Isastrea  helianthoides  (Goldf.). 
Coral-Rag ;  Nattheim,  Swabia. 
Natural  size. 


Fig.  145. 

Favia  caryophylloidcs 
From.  Coral-Rag;  Natt- 
heim.    Natural  size. 


Fig.  142. 

OrMcella  conoidea  (Reuss.).  Mio- 
cene;  Enzesfeld,  near  Vienna.  a, 
Corallum,  natural  size ;  b,  Calices 
enlarged. 


Fig.  144. 

Latomeandra  seriata 
Beck.  Coral-Rag;  Natt- 
heim. Natural  size  (after 
Becker), 


Fig.  146. 

CalamopJiyllia  stokesi  E.  and  H. 
Coral-Rag  ;  Steeple  Ashton,  England. 
Natural  size. 


Isastrea  E.  and  H.  (Fig.  143).  Corallites  prismatic,  closely  crowded,  and 
with  fused  walls.  Calices  polygonal ;  columella  imperf ect  or  absent.  Trias 
to  Cretaceous. 

Latortuandra  d'Orb.  (Fig.  144).  Like  the  preceding,  but  with  the  calices 
situated  in  short  furrows.     Trias  to  Cretaceous. 

Stylastraea  From.  Lias  ;  Europe.  Amphiastraea  From.  Upper  Jurassic  ; 
Europe.  Leptastrea,  Solenastrea,  Prionastrea,  E.  and  H.  etc.  Tertiary  and 
Recent. 

{■.  Massive  coralla  multiplying  hy  fission. 
Favia  Oken  (Fig.  145).     Corallum  massive;  calices  oval  or  distorted,  and 
united  by  confluent  costal  septa  ;  columella  spongy.     Jurassic  to  Recent.' 


>UBCLASS  II 


HEXACORALLA 


99 


Goniastrea  E.  and  H.     Corallites  prismatic,  calices  polygonal.     Septa  well 
cleveloped  ;  columella  spongy  ;  pali  in  front  of  all  cycles 
excepting  the  last.     Cretaceous  to  Recent. 

'7],  Branching  coralla  multiplying  hy  fission. 

Calamophyllia  Blainv.  (Bhabdophyllia  E.  and  H.; 
Lithodendron  p.  p.  Mich.)  (Fig.  146).  Colony  fasciculate 
or  bushy ;  corallites  very  long,  cylindrical.  Wall 
costate,  without  epitheca ;  columella  absent.  Trias, 
Jurassic  and  Tertiary.  Especially  common  in  Alpine 
Trias.      C.  clathrata  (Emmrich). 

Thecosmilia  E.  and  H.  (Fig.  147).  Colony  bushy, 
calices  dividing  by  fission,  and  more  or  less  free. 
Epitheca  corrugated,  readily  wearing  away ;  columella 
absent  or  rudimentary.  Trias  to  Tertiary.  Accord- 
ing  to  Frech  identical  with  Calamophyllia.  Very 
common  in  Triassic  and  Jurassic. 

Baryphyllia  From.     HymenophyUia  E.  and  H.,  etc.     Cretaceous. 


Fig.  147. 
Thecosmilia  tric 
(Goldf.).     Coral-Rag 
heim.    Natural  size. 


hotoma 
:    Natt- 


0.  Coralla  with  confluent  calices  increasing  by  fission. 

Leptoria  E.  and  H.  (Fig.  148).  Corallum  massive,  composed  of  labyrinthic 
rows  of  confluent  corallites  with  fused  walls.  Septa  closely  crowded, 
approaching  parallelism  ;  columella  lamellar.     Jurassic  to  Tertiary. 

Diploria  E.  and  H.     Like   the  preceding,    but  with  corallites   united  by 

produced  costal  septa  instead 
of  directly  by  their  walls. 
Cretaceous  to  Recent. 

Aspidiscus  König  {F\g.  149). 
Corallum  discoidal,  circular  or 
elliptical,  covered  on  lower  side 
with  wrinkled  epitheca.  Cali- 
cinal  furrows  radiating  from  the 
centre  outwards,  and  separated 
from  one  another  by  sharply 
crested  ridges.  In  the  centri- 
fugally  disposed  corallites  the 
outermost  septa  are  thickened, 
Cretaceous, 

Cretaceous.     Symphyllia  E.  and 


Fig.  148. 
Leptoria  koniiicki  Reuss.    Upper 
Cretaceous ;  Gosau  Valley.  Natural 


Fig.  149. 

Aspidiscus  cristatus 
König.  Middle  Cre- 
taceous ;  Batiia,  Al- 
geria.    Natural  size. 


and  form  by  their  union  a  banded  margin. 

Stiboria  Etall.     Jurassic.     Stelloria  d'Orb. 
H.     Tertiary  and  Recent. 


Family  6.     Eusmiliidae   Verrill. 

Like  the  Astraeidae,  except  that  upper  septal  edges  are  entire,  not  serrated. 

a.  Simple  coralla. 

Trochosmilia  E.  and  H.  (Fig.  150).  Turbinate,  base  acutely  pointed  or 
Septa  numerous,  extending  to  the  centre.  Without  epitheca, 
costae  granulated.  Columella  absent,  dissepiments  numerous.  Cretaceous 
and  Tertiary. 


encrusting, 


100 


COELENTERATA— ANTHOZOA 


THYLUM  II 


Coelosmilia  E.  and  H.  (Fig.  151).  Like  the  preceding,  but  with  dissepi- 
ments  sparsely  developed.     Cretaceous  and  Kecent. 

Placosmilia  E.  and  H.  (Fig.  152).  Cuneiform,  base  acutely  pointed  or 
slightly  pedunculate.    Calice  laterally  compressed,  elongated.    Septa  numerous  ; 


Fig.  150. 

Trochosmilia  granifera  Haime.  Turoiiian  ;  Bains-de- 
Rennes,  France,  a,  Profile  ;  b,  Calice  slightly  enlarged 
(after  Fromentel). 


Fig.  152. 


Fig.  151. 

Coelosmilia  laxa  E. 

and      H.       White  Placosmilia  cuneiformis  E. 

Chalk ;     Lüneburg,  and  H.     Upper  Cretaceous  ; 

Hanover.      Natural  St.  Gilgen  on  Wolfgangsee, 

size.  Anstria.     Natural  size. 


dissepiments  abundant ;  columella  foliaceous.  Epitheca  absent ;  costae  granu- 
lated.     Cretaceous. 

Diplodenium  Goldf.  Calice  laterally  compressed,  greatly  elongated  in 
transverse  direction,  and  bent  downwards  at  the  ends  so  as  to  become  crescent- 
shaped.  Columella  and  epitheca  absent.  Costae  dichotomously  or  tricho- 
tomously  furcate.     Upper  Cretaceous. 

Axosmüia  E.  and  H.  Jurassic.  Fhyllosmilia  From.  Cretaceous.  LopJio- 
smilia  E.  and  H.     Cretaceous  and  Eecent. 

ß.  Coralla  muUiplying  hy  lateral  gemmation. 

Placophyllia  d'Orb.  (Fig.  153).  Buds  originating  on  calicinal  margin  or 
sides,  and  giving  rise  to  bushy  or  massive  colonies.  Columella  styliform 
Jurassic. 


Fig.  153. 

Placophyllia  dlanthus  (Goldf.).  Coral- 
Rag ;  Nattheim.  a,  Corallum,  natural 
size  ;  b,  Calice  enlarged. 


Stylina  delabechei  E.  and  H.  Coral-Rag  ;  Steeple 
Ashton,  England,  a,  Natural  size  ;  b,  Calices  en- 
larged. 


Galaxea  Oken.  Bushy  colonies  with  cylindrical  corallites  united  by  layers 
of  finely  vesicular  coenenchyma.     Recent. 

Stylina  Lam.  (Fig.  154).  Massive  colonies,  with  corallites  united  by 
coalescent  costae.  Septa  well  developed,  disposed  in  six,  eight,  or  ten  cycles. 
Dissepiments  numerous  ;  columella  styliform.  Multiplication  by  costal  gemma- 
tion.     Profuse  in  Trias,  Jurassic,  and  Cretaceous. 


SUBCLASS  II 


HEXACORALLA 


101 


Cryptocoenia  E.  and  H.     Jurassic  and  Cretaceous. 
Massive    colonies,    with    corallites    united    by   costae. 
centre  :  colnmella  absent.     Visceral    Chamber 


Astrocoenia  deeaphylla  B.  and  H.     Upper  Cretaceous  ;  Gosau 
Valley,  Austria.    «,  Corallum,  natural  size  ;  b,  Caiices  enlarged. 


Placocoenia  d'Orb. 

Cyathopliora  Mich 
Septa   short,   not   reaching  the 
partitioned    off    by    horizontal 
tabulae.       Jurassic  .  and     Cre- 
taceous. 

Coccophyllnm  Reuss.  Massive 
colonies,  with  corallites  united 
directly  by  their  walls.  Caiices 
polygonal,  septa  numerous.  Col- 
umella  absent ;  visceral  Cham- 
ber tabulated.     Alpine  Trias. 

Pinacophyllum  Frech.  Tri- 
assic. 

Holocystis  Lonsd.  Massive  colonies,  with  corallites  united  by  costae.  Four 
of  the  septa  larger  or  stouter  than  the  rest.  Tabulae  in  visceral  Chamber. 
Cretaceous. 

Astrocoenia  E.  and  H.  (Fig.  155).  Massive  colonies.  Corallites  polygonal, 
united  by  their  walls ;  septa  numerous,  long.  Columella  styliform ;  only 
dissepiments  present  in  visceral  Chamber.     Trias  to  Tertiary. 

Stephanocoenia  E.  and  H.  Like  the  preceding,  but  with  columella 
surrounded  by  cycle  of  pali.     Trias  to  Recent. 

Phyllocoenia  E.  and  H.  {Confusastrea  d'Orb. ;  Adelastrea  Reuss).  Massive 
colonies.  Corallites  round  or  oval,  imperfectly  united  by  costae.  Septa 
strongly  developed,  thickened  in  the  middle  between  theca  and  the  centre. 
Columella  rudimentary.     Trias  to  Tertiary. 

Convexastrea  d'Orb.     Trias  to  Cre- 
^Tliaa^  taceous.       Columnastrea,    Stylocoenia   E. 

and  H.,  etc.     Cretaceous  and  Tertiary. 

y.   Coralla  multiplying  by  fission. 

Haplosmilia  d'Orb.  Bushy  colonies. 
Corallites  usually  with  dichotomously 
dividing  crests.  Caiices  circular  or 
elongated  ;  columella  styliform  ;  theca 
with  ridge-like  costae.     Jurassic. 

Plocophyllia     Reuss      (Fig.      156). 

Branching,      foliaceous,      or      massive 

colonies.     Corallites    either    becoming 

free    or  grouped   into   detached  rows. 

Columella  absent.     Tertiary. 

Barysmilia  E.  and  H.     Corallum  massive,  forming  a  thick  stem,  the  apex 

of  which  is  covered  with   short  buds.     Caiices   oval,   sometimes  disposed  in 

series  ;  columella  rudimentary.     Cretaceous. 

Stenosmilia  From.  Like  the  preceding,  but  with  lamellar  columella. 
Cretaceous. 

Pachygyra  E.  and  H.  Corallites  arranged  in  winding  rows,  and  united  by 
a  broad  mass  of  costal  coenenchyma.  Columella  lamellar.  Jurassic  and 
Cretaceous. 


Fig.  156. 

Plocophyllia  calyculata  Reuss.     Oligocene ;    Monte 
Carlotta,  near  Vicenza.     Natural  size. 


102 


COELENTERATA— ANTHOZOA 


PHYLUM  II 


Phytogyra  d'Orb.     Jurassic  and  Cretaceous  ;  Europe. 

Bhipidogyra  E.  and  H.  (Fig.  157).  Corallum  fan-shaped,  often  corrugated, 
and  with  but  a  single  calicular  furrow.  Columella  lamellar.  Jurassic  and 
Cretaceous. 


Fig.  157. 
Bhipidogyra  crassa  From.   Coral-Rag ;  Gray,  Haiite-Saone.     1/2  natural  size. 


Suborder  2.     FUNGIDA   Duncan. 

Solitary  or  colonial  corals.  Synapticulae  in  tlie  interseptal  and  mtercostal  loculi. 
Dissepiments  present  or  absent.  Septa  lamellate  and  solid  or  slightly  perforate,  or 
composed  of  a  trabecidar  lattice-work  with  numerous  perforations.  Basal  structures 
perforate  or  imperforate. 

Family  1.     Fungiidae    Dana. 

Embryo  after  becoming  attached  forms  a  trophozooid,  which  gives  rise  to  buds 
(anthoblasts) ;  these  become  detached,  forming  free  individuals  (anthocyathi).  Adult 
corallum,  simple  or  colonial,  depressed  or  mitroid  in  form.  Septa  of  higher  cycles 
perforate,  those  of  the  lower  perforate  or  solid.  Synapticula,  but  no  dissepiments 
present.  Wall  usually  perforate  in  young,  free  individuals,  subsequently  more  or  less 
compact.     No  epitheca. 

Fungia  Lamarck ;     Halomiira    Dana ;    Polyphyllia    Quoy    and    Gaimard ; 
Zoopilus   Dana ;     Cryptabacia    E.    and    H. ;    Lithactinia    Lesson ;    Herpetolitha 
Escholtz.    Recent.  Fungia  oc- 
curs  also  in  the  post-Pliocene. 

Family  2.  Agariciidae  Verrill. 

Simple  or  colonial  Fungids 
with  lamellar,  usually  imper- 
forate, septa.  Wall  solid  in 
simple  genera,  basal  wall  solid 
in  colonies,  walls  between  coral- 
lites  solid  when  developed.  Dis- 
sepiments present  or  absent. 

Microseris  From.  (Fig. 
158).  Corallum  simple,  dis- 
coidal,  circular ;  upper  side 
vaulted,  lower  flat  and  granu- 
lated.     Cretaceous. 

Trochoseris  E.  and  H.    Simple  species,  trochoid  and  fixed.   Tertiary  and  Recent. 

Cyathoseris  K  Sind  H.     (Fig.  159).     Corallum  turbinate,  attached.     Young 


Fig.  158. 


Microseris  hemis-phaerica  From.  Greensand  (Cenomanian) ;  Le 
Mans,  France,  a  and  b,  Upper  and  lower  surfaces,  enlarged ;  c, 
Profile,  natural  size. 


I.,.„ 


HEXACOKALLA 


103 


corallites  arising  from  periphery  by  costal  gemmation.     Common  outer  wall 
naked,  striated.     Cretaceous  and  Tertiary. 

Leptophyllia  Reuss  (Fig.  1 60).      Corallum  simple,  conical  or  cylindro-conicäl, 
with  superficial  calice.     Septa  numerous,  thin,  regularly-toothed  ;  solid  or  only 


Cyathoseris  siCbregxdaris  Keuss.     Oligocene  ;  Monte  Carlotta,  near  Viceiiza,  Italy. 
a,  Top  view  ;  h,  Side  view,  natural  size. 


Fig.  160. 

Leptophyllia  sinuosa 
From.  Neocomian ;  St. 
Dizier,  Haute  -  Marne. 
Natural  size. 


partially  perforate.     Thin  dissepiments  present.     Thin  epitheca  present. 

Thamnasteria  Lesauv.  {Thamnastraea  auct.,  of  which  T.  lamourouxi  is  the 
type.)  Jura.  Lophoseris  E.  and  H. ;  Agarkia  Lam. ;  Siderastrea  Blv.,  etc. 
Tertiary  and  Eecent. 

Family  3.     Anabaciidae    Duncan. 

(Pseudoasfraeinae  and  Pseudoagaricinae  Pratz ;  Microsolenidae  Gregory.) 

Simple  coralla,  or  composite,  hasally  expanded  or  massive  colonies.  Septa 
numerous,  perforate,  and  composed  of  calcareous  hodies  (traheculae)  arranged  in 
vertical  or  fan-shaped  rows  (trabeculate).  Theca  hetween  individual  corallites  ahsent, 
hut  may  he  present  on  under  side  of  corallites  or  on  lower  side  of  the  common 
stock.  Interseptal  loculi  with  synapticula  and  dissepiments.  Abundant  from  Trias 
to  Cretaceous ;  rarer  in  Tertiary  and  Recent. 

Änahacia  d'Orb.  Simple,  free,  discoidal,  or  lenticular  coralla,  with  flat 
base.  Upper  side  vaulted,  calice  slit-like.  Septa  very  numerous,  thin,  and 
united  by  synapticulae.     Theca  absent.     Jurassic  ;  Europe. 

Genabacia  E.  and  H.  Like  the  preceding  but  composite,  the  central  calice 
being  surrounded  by  a  row  of  smaller  calices.     Jurassic ;  Europe. 

Micrabacia  E.  and  H.     Cretaceous  ;  Europe. 

Omphalophyllia  Laube.  Simple,  turbinate  or  sub-cylindrical,  attached, 
and  covered  with  epitheca.  Septa  very  numerous,  upper  edges  granulated. 
Calice  shallow,  columella  styliform.     Alpine  Trias. 

Cyclolites  Lam.  (Fig.  161).  Simple,  free,  discoidal,  upper  side  vaulted, 
lower  flat  and  covered  with  corrugated  epitheca.  Septa  very  thin,  extending 
to  the  centre,  extremely  numerous,  composed  of  vertical  rows  of  traheculae, 
and  united  by  synapticulae  and  dissepiments.  Very  abundant  in  Cretaceous, 
rare  in  Jurassic  and  Eocene. 

Dimorpharaea  From.  (Fig.  162,  A,  B).  Composite,  laterally  expanded  and 
pedunculate,  or  mushroom-shaped  coralla.     Common  wall  restricted  to  lower 


104 


COELENTERATA— ANTHOZOA 


PHYLUM  II 


side  of  corallum ;  individual  corallites  without  proper  walls,  but  united  by 
costal  septa.  Columella  styliform  or  rudimentary.  Septa  well  developed, 
composed  of  fan-shaped  rows  of  cylindrical  trabeculae,  and  united  by  synapti- 
culae  and  dissepiments.     Very  abundant  from  Trias  to  Oligocene. 


Cyclolites  undulata  Lam. 


Fig.  IGl. 

Upper  Cretaceous  ;  Gosau  Valley,  Salzkainmergut. 
surface  ;  c,  Lateral  aspect  of  septum,  natural  size. 


(I,  Side  view  ;  h,  Lower 


Dimorphastrea  d'Orb.  Like  the  preceding,  but  with  calices  concentrically 
arranged  about  a  central  individual.     Trias  to  Tertiary. 

Co7noseris  d'Orb.  (Fig.  163).  Like  Dimorpharaea,  but  with  calices  separated 
into  groups  by  ascending  flexuous  ridges.     Jurassic  and  Tertiary. 

Astraeomorpha  Eeuss.  Coralla  composite,  tuberous,  basally  expanded,  or 
branching,  and  covered  with  corrugated  epitheca.  Corallites  small,  united  by 
Short  and  stout  costal  septa ;  columella  styliform.     Trias  to  Oligocene. 


FKi.  162. 


A,  Dimorplmraea,  Lateral  surface  of  costal  septum,  enlarged 
(8/1),  showing  ftabecular  Constitution  ;  m,  Line  of  junction  of 
two  septa  belonging  to  difterent  corallites  ;  t,  Trabeculae  ; 
p,  Trabecular  lacunae  (after  Pratz).  B,  Dimorpharaea  agari- 
cites  (Goldfuss).  Upper  Cretaceous  ;  Gosau,  Salzkainmergut. 
Portion  of  upper  surface  of  corallum,  natural  size. 


Fi(i.  163. 

Comoseris  conferta  Reuss.    Oligocene  ;  Monte 
Carlotta,  near  Vicenza.     Twice  enlarged. 


Microsolena  Lamx.  Colony  massive,  polymorphous,  mammiliform,  conical, 
with  a  broad  base,  nearly  spherical,  turbinate  and  pedunculate.  Trias  and 
Jurassic. 


Suborder  3.     PERFORATA   Milne  Edwards  and  Halme. 

Skeleton  huilt  up  of  small  calcareous  hodies  (sclerites),  between  which  are  empty 
interstices  of  greater  or  lesser  size.  Theca  formed  hj  fusion  of  outer  septal  edges  or 
absent.  Interseptal  loculi  empty  throughout  or  traversed  by  synapticida  or 
dissepiments. 


SÜBCLASS  II 


HEXACORALLA 


10^ 


Family  1.     Archaeocyathidae  Walcott.i 

Simple,  turhinate,  or  sub-cylindrical  coralla.  Septa  and  theca  porous ;  inner 
septal  edges  united  hy  perforated  interiar  wall,  which  encloses  a  hollow  central  space. 
Synapticula  present  in  interseptal  loculi. 

All  biit  one  of  the  genera  described  up  to  the  present  time  (Archaeocyathus 
Bill.,  Ethmophyllum  Meek,  Spirocyathus  Hinde,  Protopharetra  Bornem.,  etc.) 
occur  in  the  Cambrian  rocks  of  North  America,  Spain,  Sardinia  and  Aus- 
tralia.  Aükokania  Walcott  is  known  from  the  Lower  Huronian  of  Ontario. 
They  represent  possibly  a  distinct  order  of  the  Madreporaria. 


Family  2.     Eupsammidae  Miliie  Edwards  and  Haime. 

Corallum  simple  or  hecoming  composite  hy  lateral  gemmation.  Septa  very 
numerous,  sometimes  united  hy  synapticula,  and  frequently  witli  their  inner  edges 
fused  together.  Theca  naked  or  covered  with  epitheca,  and  formed  hy  thickening  of 
the  septal  edges.     Silurian  to  Recent. 


Calostylis   Linds.       Corallum    simple,    sub-cylindrical,    or    composite    and 
multiplying   by  lateral  gemmation.     Septa  very   numerous,   of   spongy  con- 
sistency,  and  either  fused  together  or  united  by  synapticulae. 
Columella  thick,  spongy  ;  wall  covered  with  epitheca.      Silurian  ; 
Gotland.      This  genus  probably  belongs  to  the  Tetracoralla. 

Haplaraea  Milasch.     Simple,  cylindrical  coralla,  with  broad 


Fio.  164. 

Eupsammia 
t  rochtformis 
(Pallas).  Cal- 
caire  Grossier ; 
Chaussy,  iiear 
Paris.  Natural 
size. 


I 


'^^^^»sf^ist 


Fig.  165. 
Eahuwphyllia    sinuata    Reuss. 
Oligocene  ,         Waldböckelheiin, 
Prussia.      a,    Natural    size; 
b,  Number  of  septa  enlarged. 


Fig.  166. 


Steplumophyllia  elegans  (Bronn).  Pliocene ; 
Stazzano,  near  Modena,  Italy.  a  and  h,  Upper 
and  lower  surfaces,  enlarged  ;  c,  Profile,  natural 


encrusting  base.  Septa  numerous,  extending  to  the  centre,  perforated 
by  large  apertures,  and  sometimes  fused  together  or  united  by  synapticulae. 
Dissepiments  also  present,  but  no  columella.     Jurassic  and  Cretaceous. 

Eupsammia 'E.  and  H.  (Fig.  164).  Conical  or  turbinate,  acutely  pointed, 
free.  Septa  very  numerous,  arranged  in  five  cycles,  those  of  the  last  cycle 
stouter  than  the  rest.     Columella  present  or  absent.     Eocene  to  Recent. 

Balanophyllia  Wood  (Fig.  165).  Simple,  sub-cylindrical,  attached  by 
the  base.  Columella  spongy ;  septa  closely  crowded,  partly  fused  together. 
Eocene  to  Recent. 

Stephanophyllia  Mich.  (Fig.  166).     Simple,  discoidal;  base  horizontal,  calice 

1  Billings  E.,  Palaeozoic  Fossils  of  Canada,  i.,  1861-65.— WWc-o^^,  C.  D.,  Bull.  U.S.  Geol. 
Survey,  No.  30,  1886.— ßor7iema?iw,  /.  G.,  Versteinerungen  des  Canibrischen  Systems  von  Sardinien. 
\%%Q.— Hinde,  G.  J.,  Quart.  Journ.  Geol.  Soc,  1889,  vol.  x\v.—Lambe,  L.  M.,  Revision  of  the 
Genera  and  Species  of  Canadian  Palaeozoic  Corals.  Geol.  Surv.  Canada,  Contrib.  to  Canad.  Palaeont., 
1899,  vol.  \\.— Taylor,  W.  T.  G.,  The  Archaeocyathinae.     Mem.  R.  Soc.  S.  Aust.,  1910,  vol.  ii. 


106 


COELENTERATA— ANTHOZOA 


PHYLUM  II 


circular.     Septa  numerous ;  the  six  priiicipal  septa  extending  to  the  centre, 
the  remainder  with  fused  inner  edges.      Cretaceous  and  Tertiary. 

^^  Dendrophyllia     Blv.     (Fig.     167).        Corallum 

branching,  increasing  by  lateral  gemmation. 
Calices  oval ;  septa  numerous  and  slender,  those 
of  the  last  cycle  extending  to  the  spongy 
columella,  and  fused  with  the  converging  ends 
of  shorter  septa  of  preceding 
cycle.      Tertiary  and  Recent. 

Lohopsammia,  Stereopsammia 
Edw.  and  H.  Eocene.  Astroides 
E.  and  H.  (Fig.  97).     Kecent. 

Family  3.     Poritidae    Dana. 

Composite  coralla  composed  of 
porous    sderenchyma.       Corallites 
small ;  septa  as  a  rule  only  moder- 
Fio.  167.  ately   numerous,   sometimes  repre- 

DendrophyUia  elegans  Duncan.      Oligocene ;   Brockenhurst,     Seuted     by     TOWS     of    trabeculae     OT 
England,     a,  Corallum,  natural  size  ;  b,  Transverse  section  of     7  77  m.  i       1 

caiice,  eniarged,  iameUae.     I  fieca  aosent. 


Subfamlly  A.     Spongiomorphinae   Frech. 

Corallum  composed  of  thicJc  trabeculae  and  strengthened  by  horizontal  synapticulae. 
Calices  very  imperfectly  differentiated  from  coenenchyma,  and  without  distinct  septa. 
Dissepiments  usually  sparsely  developed. 

Of  the  genera  belonging  to  this  subfamily,  Spongiomorpha,  Heptastylis  and 
Stromatomorpha  Frech,  are  found  in  the  Alpine  Trias  (Rhaetic  and  Zlambach 
beds).  These  are  all  tuberous,  composite  coralla  of  extremely  irregulär  form. 
In  Spongiomorpha  and  Heptastylis,  six  septa  are  indicated  by  somewhat  regularly 
disposed  columns  of  trabeculae ;  and  in  the  latter  form  these  are  bound 
together  by  synapticulae  which  are  projected  at  equal  altitudes,  and  form 
perforated   horizontal    storeys.      In  a  b 

Stromatomorpha    no    radial    arrange- 
ment  of  the  trabecular  septa  exists. 

Palaeacis  E.  and  H.  (Sphenopo- 
terium  Meek  and  Worth.),  occurring 
in  the  Lower  Carboniferous  limestone 
of  North  America  and  Scotland,  per- 
haps  also  belongs  here. 


Fig.  168. 
Adinacis   elegans  Reuss.     Upper  Cretaceous ;    Gosau 
Valley,  Salzkaramergut.    a,  Upper  surface,  natural  size  ; 
h,  Transverse  section,  eniarged  ;  c,  Longitudinal  section, 
eniarged  (after  Reuss). 


Subfamily  B.      Poritinae  Milne  Ed- 
wards and  Haime. 

Septa  not  very  numerous,  well  developed. 
Corallites  united  by  their  porous  walls. 

Litharaea  E.  and  H.  (Fig.  169).  Massive  coralla.  Calices  sub-polygonal, 
septa  generally  in  three  cycles  ;  columella  spongy.     Eocene  and  Miocene. 

Rhodaraea  E.  and  H.  Massive  coralla.  Spurious  walls  of  corallites  thick  ; 
pali  prominent.     Miocene  and  Recent. 


SÜBCLASS  II 


HEXACORALLA 


107 


Porites  Link  (Fig.  170).     Massive  or  branching  coralla.     Calices  shallow, 
polygonal ;  septa  irregularly  reticulated,  usually  twelve  in  number ;  columella 


Litharaea  ivehsterl  (Bowerb.).  Eocene ;  Bracklesliam 
Bay,  England,  a,  Coralluin,  natiiral  size  ;  h,  Four  calices 
enlarged. 


Fig.  170. 

Porites  incrustans  Reuss.  Miocene  ;  Mo- 
ravia.  a,  Tranverse  section ;  b,  Longi- 
tiidinal  section.  Both  tigures  highly  magni- 
fied. 


papillous,  surrounded  by  a  single  cycle  of  pali,  the  latter  five  or  six  in 
number,  and  not  very  distinct  from  the  septal  ends.  Endotheca  exists 
sparingly,  and  may  be  dissepimental  or  tabulate,  or  may  be  mere  stereoplasm. 
Cretaceous  to  Recent.    Thegenus  b  c 

Porites  is   one    of    the   most  im-  a  ^^^      . 

portant  of  existing  reef-builders.  -^^^f^s^^    ^ 

Subfamily  C. 
Alveoporinae    Verrill. 

Septa  composed  of  detached 
traheculae,  spines,  or  reticulated 
lamellae,  Theca  perforate.  Vis- 
ceral Chamber  with  perforate  tabulae. 


Alveopora   Quoy    and    Gaim. 
(Fig.     171).       Massive     coralla. 
Calices    small,  polygonal.    Septa 
represented    by    detached    spinous  processes. 
remotely  situated.     Tertiary  and  Recent. 

KonincUa  E.  and  H.     Cretaceous  ;  Europe. 


Fig.  171. 
a,Alveoporaspongiosa'Dm\&.  Recent ;  Fiji  Islands.  Longi- 
tudinal  section  of  corallite  showing  perforate  vvalls and  tabulae; 
h,  Alveopora  rudis  Reuss.  Nummulitic  liniestone  ;  Oberburg, 
Styria,  Vi ;  c,  Calices,  greatly  enlarged.  (Fig.  a,  after  Dana ; 
h,  after  Reuss.) 


Tabulae   sparsely   developed, 


Family  4.     Acroporidae    Verrill. 

Cor)iposite,  branching,  lobate,  foliaceous,  or  massive  coralla  with  corallites  embedded 
in  a  canaliculated  and  reticulated  coenenchyma.  Septa  (6-24)  compact,  sometimes 
imperfectly  developed.  Two  long  septa  often  projected  from  opposite  sides  and  meeting 
in  the  centre. 

The  genus  Äcropova  Oken  (Madrepora  auct.,  non  Madrepora  Linn.,  1758) 
(Fig.  172),  is  an  important  agent  in  the  construction  of  existing  coral  reefs, 
and  builds  colonies  sometimes  of  considerable  size.  It  occurs  sparsely  in  the 
fossil  State  in  Tertiary  strata  of  various  regions. 

Actmacis  d'Orb.  (Fig.  168).  Massive  or  branching  coralla.  Coenenchyma 
abundant,  granulated ;  septa  stout,  of  nearly  uniform  proportions,  columella 
papillous ;  pali  in  front  of  all  the  septa.     Cretaceous  and  Tertiary. 


108  COELENTERATA— ANTHOZOA  phylum  ii 

Astreopora  Blv.  Massive  coralla.  Coenenchyma  porous  and  on  upper 
surface  echinulate.  Septa  of  dissimilar  proportions ;  columella  and  pali 
absent.     Tertiary  and  Recent. 

Dendracis  E.  and  H, ;  Cryptaxis  Reuss.      Tertiary. 

Turbinaria  Oken  (Gemmipora  Blv,).  Corallum  foliaceous.  Coenenchyma 
tolerably  compact  and  finely  echinulate.  Septa  of  similar  proportions : 
columella  spongy.     Cretaceous  to  Recent. 


Range  and  Distribution  of  the  Hexacoralla. 

The  group  Aporosa  of  the  Hexacoralla  begins  as  the  Tetracoralla  disappear, 
and  develop  a  great  variety  of  forms  in  the  Trias,  from  the  Mesozoic  onward 
to  the  present  day  they  have  continued  to  play  a  leading  part  in  the  con- 
struction  of  coral-reefs.  Of  the  f amilies  constituting  the  Aporosa,  the 
"  Astraeidae  "  is  by  all  odds  the  most  important  and  most  protean,  in  com- 

parison  to  which  the  Fungida,  Stylo- 
phoridae,  Pocilloporidae,  Oculinidae  and 
Turhinolidae  fall  into  greatly  subordinate 
rank.  The  other  f amilies  are  all  younger 
than  the  "^s/raßw/ae/'not  beginninguntil 
the  Jurassic,  the  Pocilloporidae,  indeed,  not 
until  the  Tertiary. 
Fig.  172.  The    Eupsammidae    and    Poritidae    of 

Jcroporo  ajifirZica (Duncan).  Oligocene;  Brocken-     the    Perforata    OCCUr    Sporadicallv     in    the 
hurst,  England,     a,  Calices  enlarged ;  b,  Longi-     ^-i       •  t  r~i      ^         -r  ^  •^      -.    • 

tudinal  section,  greatly  enlarged.  bllurian  and  üarboniterOUS,  whllc  it  IS  UOt 

until  the  Trias  that  the  Anabraciidae  and 
Poritidae  develop  a  large  variety  of  forms ;  from  the  Trias  to  the  Tertiary, 
however,  these  genera  continue  to  be  important  reef-builders.  The  Eupsam- 
midae attain  their  greatest  development  in  the  Tertiary  and  Recent,  while  the 
Acroporidae  belong  almost  exclusively  to  the  present  period. 

Occasional  isolated  deep-sea  forms  are  met  with  in  most  of  the  several 
geological  periods,  but  the  usual  mode  of  occurrence  of  the  Hexacoralla  is 
associated  in  masses  in  coral  limestones ;  the  limestones  may  be  of  very  vari- 
able thicknesses,  but  as  a  rule  are  interstratified  between  deposits  of  distinctly 
littoral  character.  Ancient  coral-reefs  most  nearly  resemble  modern  fringing 
or  barrier  reefs,  but  not  atolls,  the  origin  of  which  is  clearly  dependent  upon 
peculiar  conditions. 

The  St.  Cassian,  Zlambach  and  Rhaetic  beds  of  the  Alpine  Trias  contain 
large  numbers  of  reef-building  Hexacoralla;  but  the  pure  limestones  and 
dolomites  of  the  Alps,  as  well  as  the  Trias  outside  the  Alpine  region,  are 
frequently  either  almost  or  entirely  destitute  of  coral  remains. 

In  the  Lias,  coral-reefs  have  been  found  in  England,  Luxemburg  and 
Lorraine.  Certain  beds  of  the  Dogger,  usually  of  but  meagre  thickness,  are 
occasionally  charged  with  corals,  as  in  Swabia,  the  Rhine  Valley  in  Baden,  the 
Swiss  Jura,  Normandy  and  England.  Coral  limestones  are  abundantly 
developed  in  the  Upper  Jurassic  of  the  Jura  Mountains  in  France  and  Switzer- 
land,  in  Lorraine,  Southern  Baden,  Swabia  (Nattheim,  Blaubeuern),  Bavaria 
(Kelheim),  many  places  in  France  and  England,  as  well  as  in  the  whole  province 
of    the   Alps,    Carpathians,    Cevennes   and   Apennines ;    here   the   uppermost 


I 


CLAss  III  ALCYONARIA  109 

horizon  (Tithonian)  is  especially  characterised  by  their  development.  Reef 
corals  are  also  greatly  developed  in  the  Cutch  (Jurassic)  series  of  India. 

In  the  Lower  Cretaceous  (Neocomian)  coral-reefs  are  found  in  France 
(Haute -Marne  and  Yonne),  Crimea  and  Mexico;  while  the  Urgonian  of 
Switzerland  and  the  Bavarian  Alps  is  occasionally  charged  with  corals.  In  the 
Turonian  and  Senonian  of  the  Alps  (Gosau  Beds),  Pyrenees  and  the  Provence, 
numerous  coral-reefs  occur,  usually  accompanied  by  Budistae  ;  elsewhere,  how- 
ever,  except  in  Holland  (Maestricht)  and  Denmark  (Faxoe),  the  Upper 
Cretaceous  contains  but  a  limited  number  of  reef-building  Hexacoralla. 

In  the  older  Tertiary  (Eocene  and  Oligocene)  occurrences  of  coral-reefs  are 
known  on  the  northern  and  southern  flanks  of  the  Alps  and  Pyrenees,  in  Arabia, 
India,  the  West  Indies,  and  in  Georgia,  Florida,  Alabama,  Mexico  and  Central 
America ;  outside  these  areas  their  distribution  is  mostly  sporadic.  In  the 
Miocene  and  Pliocene  the  true  coral-reefs  retreat  more  and  more  towards  the 
equator  (Red  Sea,  Java,  Japan,  Gulf  of  Mexico),  while  the  Hexacoralla  which 
persist  in  geologic  formations  within  the  temperate  zone  (Vienna  Basin,  Italy, 
Touraine)  constitute  but  an  insignificant  feature  of  the  general  fauna. 

[Tlie  foregoing  sections  on  the  Tetracorallä  and  Hexacoralla  have  been  revised  by  Dr.  T. 
Wayland  Vaughan,  of  the  United  States  National  Museum  at  Washington.  It  sliould  be 
observed  tliat,  in  the  present  unsatisfactory  state  of  our  knowledge  of  these  organisms,  the 
Classification  adopted  in  this  work,  although  perhaps  as  good  as  any  available,  is  tentative  in 
character. — Editok.] 


Subclass  3.     ALCYONARIA    Milne  Edwards. 

{Octacfinia  Ehrenberg  ;  Oäocoralla  Haeckel). 

Composite  colonies,  rarely  simple  polyps,  the  individuals  provided  with  eight 
mesenterial  folds  and  eight  broad,  pinnately  fringed,  or  plumose  tentacles,  which  form 
a  Single  cyde  about  the  mouth, 

Hard  skeletal  elements  are  very  generally  developed  in  the  Alcyonaria,  being 
absent  in  comparatively  few  forms,  and  are  remarkable  for  their  manifold 
variety  ;  they  occur  either  detached  in  the  ectoderm  and  mesoderm,  or  are 
closely  packed  together  at  the  base  to  form  a  horny  or  calcareous  axis  (sclero- 
basis),  about  which  the  polyps  are  distributed.  Sometimes  the  calcareous 
bodies  (sderodermites)  form  compact  tubes  which  are  periodically  partitioned 
off  into  storeys  with  the  upward  growth  of  the  animal.  Reproduction  is 
accomplished  either  sexually,  or  asexually  by  basal  or  lateral  gemmation, 
rarely  by  fission. 

Only  the  calcareous  parts  are  known  in  the  fossil  state,  such  as  the  solid 
axes,  detached  skeletal  elements,  tubes  and  composite  coralla ;  the  horny 
structures  are  totally  destroyed  during  fossilisation.  The  Alcyonaria  make 
their  appearance  in  the  Ordovician,  but  rarely  occur  in  great  abundance. 

Family  1.  Alcyonidae    Milne  Edwards  and  Haime. 

Fixed,  fleshy,  lobate,  or  ramose  polyp  Stocks  (very  rarely  simple  individuals),  with 
echinulate  or  spicular  calcareous  bodies  (sderodermites)  occurring  detached  in  the 
soft  parts. 

Isolated  sderodermites  readily  escape  Observation,  owing  to  their  minute 


110 


COELENTERATA— ANTHOZOA 


PHYLUM  II 


size  and  fragile  Constitution.     They  have  been  detected  as  yet  only  by  Pocta 
in  the  Upper  Cretaceous  strata  near  Laun,  Bohemia. 


I 


Fig.  173. 

Graphularia  de- 
sertorum  Zitt. 
Nummulitic  lime- 
stone (Bocene) ; 
Farafreh,  Libyan 
Desert,  Africa.  a, 
Axis,  natural  size  ; 

b,  Section  of  same  ; 

c,  Striated  surface, 
enlarged. 


Family  2.      Pennatulidae    Milne  Edwards  and  Haime. 

Folyp  Stocks  with  hase  embedded  in  sand  or  mud,  and  with  horny 
or  calcareous  sclerohase  ;  polyps  dimorphic. 


Slender,  round  or  quadrate  calcareous  axes  referable  to  tbe 
Pennatulidae  have  been  detected  with  certainty  only  in  the 
Trias  (Prographularia  Frech.),  Cretaceous  (Pavonaria  Cuv. ; 
Pennatulites  and  Palaeosceptron  Cocchi ;  Glyptosceptron  Böhm), 
and  Tertiary  (Graphularia  E.  and  H.)  (Fig.  173). 


Family  3.     Gorgonidae    Milne  Edwards  and  Haime. 

Fixed,  branching  or  fan-skaped  colonies,  vnth  horny  or  calcareous 
solid  sclerohase,  or  with  jointed  axis  composed  of  alternating  horny 
and  calcareous  segments. 

All  the  genera  possessing  horny,  flexible  axes  (Gorgonia, 
Rhipidogorgia,  etc.)  are  perishable.  Detached  remains  referable 
to  Primnoa,  Gorgonella  and  Firgidaria,  the  axes  of  whicli  are 
composed  of  both  horny  and  calcareous  layers,  have  been 
described  from  the  Tertiary.  In  the  genus  Isis  the  axis  con- 
sists  of  cylindrical  calcareous  segments  alternating  with  horny 
connecting  joints.  It  is  found  fossil  in  the  Tertiary,  and  has 
been  reported  also  from  the  Cretaceous.  The  genus  MoltJcia, 
occurring  in  the  Upper  Cretaceous,  has  cylindrical  joints  which 
are  pitted  with  slight  depressions  indicating  the  position  of 
branches.  In  the  red  or  gem  coral  (Corallium  Linn.)  the  axis 
is  built  up  of  spiniform  sclerites,  which  are  united  by  a  fibro- 
crystalline  calcareous  matrix  impregnated  with  organic  matter. 
It  occurs  only  rarely  in  the  fossil  state,  but  is  known  from 
the  Cretaceous  and  Tertiary. 


Family  4.     Tubiporidae    Milne  Edwards  and  Haime. 

Coralla  composed  of  red-coloured  parallel  calcareous  tuhes  connected 
by  horizontal  plates. 


The  cylindrical  tubes  of  the  recent  Organ-pipe  Coral  (Tubi- 
pora)  are  composed  of  spiniform  sclerites,  which  are  united  with  one 
another  directly  in  such  manner  as  to  enclose  small  hollow  Spaces  appearing 
superficially  as  pores.  The  connecting  horizontal  plates  or  floors  are  tra- 
versed  by  canals  which  communicate  with  the  visceral  Chambers  of  the 
tubes  by  means  of  numerous  round  openings.  New  corallites  are  budded 
from  their  upper  surfaces.     Unknown  in  fossil  state. 

^  Poita,  Philipp,  Sitzimgsber.  Akad.  Wiss.  Wien,  1885,  vol.  xcii. 


SÜBCLASS  III 


ALCYONARTA 


111 


Family  5.       Helioporidae    Moseley.^ 

Calcareous  coraMa,  composed  of  two  series  of  tuhiform  corallites  ;  the  larger  tubes 
(autopores)  are  embedded  in  a  strongly  developed  coenenchyma  made  up  of  smaller 
tubes  (siphonopores).  Both  autopores  and  siphonopores  are  dosely  tabulate ;  the 
autopores  are  provided  with  ridge-like  pseudosepta,  which,  however,  do  not  correspond 
numerkally  with  the  tentacles. 

The  affinities  of  the  Helioporidae  with  the  Alcyonaria  were  first  pointed  out 
by  Moseley.  The  larger  polyps  inhabit  the  autopores,  and  are  furnished  with 
eight  mesenterial  folds  and  a  crown  of  eight  tentacles ;  while  the  smaller 
polyps,  which  are  without  either  tentacles  or  sexual  organs,  are  lodged  in  the 
siphonopores.  The  skeleton  is  composed  of  calcareous  trabeculae,  the  same  as 
in  the  Hexacoralla,  from  whose  centres  of  calcification  radial  fibres  extend 
outwards  in  caespitose  fashion.  The  siphonopores  multiply  by  intermural 
gemmation,  while  the  autopores 
are  formed  by  the  coalescence 
and  fusion  of  a  number  of  the 
siphonopores. 

Heliopora  Blainv.  (Fig.  174, 
A,  B).  Corallum  massive  or 
ramose;  autopores  with  12-25 
slightly  developed  pseudosepta, 
and  embedded  in  a  coenen- 
chyma made  up  of  smaller 
siphonopores :  the  latter  are 
more  closely  tabulate  than 
the  autopores.  Cretaceous  to 
Recent. 

Polytremacis  d'Orb.  (Fig.  174,  C).  Like  Heliopora,  but  pseudosepta  much 
more  strongly  developed,  sometimes  reaching  nearly  to  the  centre.    Cretaceous. 

Octotremacis  Gregory  {Polysolenia  Reuss  non  Ehrenb.).     Miocene ;  Java. 


Fig.  1T4. 

Heliopora  partschi  (Reuss).  Upper  Cretaceous  ;  St.  Gilgen  on 
Wolfgangsee,  Salzkammergut.  J,  Corallum,  natural  size.  iJ,  Por- 
tion of  surface,  enlarged.  C,  Polytremmis  hlainvilleana  Reuss. 
Upper  Cretaceous ;  Gosau,  Salzkammergut.  Vertical  section, 
enlarged. 


Family  6.     Heliolitidae    Lindström.2 

Corallum.  massive,  more  rarely  ramose,  varying  from  spheroidal  to  flabellate, 
composed  of  tubulär  or  vesicular  coenenchyma  enclosing  corallites  in  the  form  of  large 
cylindrical  and  numerous  smaller  angular  cells ;  both  the  macro-  and  microcorallites 
with  tabulae.  Usually  twelve  septa  present  in  the  large  cylindrical  cells,  but  these 
are  often  rudimentary.  No  mural  pores ;  basal  epitheca  present.  Silurian  and 
Devonian. 

The  genera  assigned  to  this  family  exhibit  in  their  general  appearance, 
finer  structure  and  manner  of  multiplication,  considerable  resemblance  to 
Heliopora,  with  which  they  were  associated  by  Moseley,  Nicholson,  Bourne, 

1  Moseley,  IL  N.,  The  Structure  and  Relations  of  Heliopora  caerulea.     Pliilos.  Trans.  Royal 
Society,  1877,  vol.  clxvi. — Bourne,  G.  C,  On  the  Structure  and  Affinities  of  Heliopra  caerulea. 
Ibid.,  1895,  vol.  clxxxvi.  pt.  1. 

2  Lindström,  G.,  Reniarks  on  the  Heliolitidae.  K.  Svensk.  Vetensk.  Akad.  Handl.,  1899, 
vol.  xxxii. — Klär,  J. ,  Die  Koralleufauna  der  Etage  5  des  norwegischen  Silursystems.  Palaeontogr. 
1899,  vol.  xlvi. — Idem,  Revision  der  mittelsilurischen  Heliolitiden,  etc.  Videnskabs-Selskabets 
Skrift.  I.  Classe,  No.  10,  1903. 


112 


COELENTERATA— ANTHOZOA 


PHYLÜM  II 


Gregory  and  others.  Here,  as  in  Heliopora,  the  autopores  are  formed  by 
coalescence  of  numerous  siphonopores  in  the  coenenchyma.  On  the  other  hand 
the  corallites  in  the  Heliolitidae  have  well-developed  walls  of  compact  homo- 
geneous  matter,  and  as  a  rule  also  tvvelve  strong  septa  are  present,  sometimes 
reaching  nearly  to  the  centre  of  the  cylindrical  Chambers.  On  account  of 
these  differences  the  family  has  been  separated  from  Heliopora,  and  some 
authors  have  proposed  to  associate  them  with  certain  Hexacoralla,  or  with 
the  problematical  Tabulata. 

Heliolites  Dana  (StelliporeUa  Wenzel;  Nicholsonia  Kiär)  (Fig.  175).  Corallum 
massive,  nodular  or  ramose.  Autopores  with  twelve  more  or  less  strongly 
developed  pseudosepta,  though  occasionally  represented  by  rows  of  spinules, 
and  frequently  with  central  columella.  Siphonopores  without  septa,  and 
multlplying  by  fission  or  intermural  gemmation.  Abundant  from  Ordovician 
to  Devonian. 

Plasmopora  E.  and  H.  (Diploepora  Quenst.).  Like  Heliolites,  but  having 
walls  of  the  siphonopores  incomplete,  and  tabulae  of  contiguous  tubes  fused 
together  so  as  to  form  a  vesicular  tissue.     Ordovician  to  Devonian. 


iyv. 


mMi"' 


Heliolites  porosa  Goldfuss. 


Devonian  ; 
enlarged 


Fig.  175. 

Eifel.     ^,  Corallum,  natural  size.     iJ,  Portion  of  outer  sui  1 
.     C,  Longitudinal  section,  enlarged. 


Profaraea  E.  and  H.  (Stylaraea  E.  and  H.,  7ion  Seebach).  Low  incrusting 
corallites,  with  relatively  little  coenenchyma.  Tabulae  present  in  the  autopores. 
According  to  Kiär,  this  form  and  Coccoseris  Eichwald  are  closely  related,  and 
perhaps  identical.     Ordovician  and  Silurian  ;  Scandinavia  and  North  America. 

Cosmiolithes  Lindstr.  Corallites  thin,  lamelliform.  Coenenchymal  pores 
thick-walled,  not  all  of  the  same  size,  with  concave  or  obliquely  directed 
tabulae.  Autopores  with  well  -  developed  septa.  Silurian ;  G.  ornatus 
Lindstr. 

Plasmoporella,  Palaeoporites  and  Trochiscolithus  Kiär.  Silurian  ;  Scandinavia. 
Acantholithus,  Pycnolithus  Lindstr.  Eelated  genera  having  the  same  distri- 
bution. 

Appendix  to  the  Anthozoa. 

Sub Order.     TABULATA   Milne  Edwards  and  Halme.  ^ 

Invaridbly  composite  coralla  composed  of  tubiform  or  prismatic  corallites.  Walls 
thick,  independently  calcified,  compact  or  perforated  hy  connecting  mural  pores.    Septa 

^  Literature  :  Lindström,  O.,  Affinities  of  the  Anthozoa  Tabulata.  Ann.  Mag.  Nat.  Hist.,  1876, 
ser.  4,  vol.  xviii. — Nicholson,  H.  A.,  On  the  Structure  and  Affinities  of  the  Tabulate  Corals  of  the 
Palaeozoic  Period.     London,  1879. — Roemer,  F.,  Lethaea  Palaeozoica,  i.,  1883,  p.  416. —  Waagen, 


suBCLAss  III  TABULATA— FAVOSITIDAE  113 

hut  slighüy  developed  (usualli/  six  or  twelve),  sometimes  7'epresented  merely  hy  vertical 
ridges  or  rows  of  spines,  and  sometimes  entirely  absent.  Visceral  Chamber  partitioned 
ojf  into  successive  storys  by  tabulae.     Synapiiculae  and  dissepiments  wanting. 

To  the  Tabulata  were  originally  assigned  by  Milne  Edwards  and  Haime 
all  corals  having  numerous  tabulae  and  rudimentary  septa.  Later  researches 
have  shown,  however,  that  some  of  these  forms  (Focilloporidae)  belong  to  the 
Aporosa,  others  (Ilelioporidae)  to  the  Alcyonaria,  and  still  others  (MiUepora)  to 
the  Hydrozoa.  The  majority  of  the  typical  Tabulata  (Favositidae,  Syringoporidae, 
Halysitidae)  exhibit  close  relationships  to  the  Hexacoralla ;  but  since  they  are 
for  the  most  part  now  extinct  and  are  largely  confined  to  the  Paleozoic  rocks, 
the  determination  of  their  systematic  position  is  a  matter  of  much  difficulty. 
The  ontogeny  of  the  corallites  in  the  Tabulata  shows  that  the  development  of 
mural  pores  is  homologous  with  the  process  of  gemmation.  Reproduction 
sometimes  takes  place  by  fission,  but  generally  by  means  of  buds  from  the 
edges  of  the  calices  at  various  stages  during  the  growth  of  the  parent  corallites. 
Buds  are  given  ofF  early  in  Aulopora,  producing  basal  corallites  only ; 
periodically  in  Romingeria,  producing  verticils  of  corallites ;  periodically  and 
on  one  side  in  Halysites,  producing  linear  series  of  adjacent  corallites  ;  and 
very  frequently  in  Favosites,  etc.,  producing  compact  coralla  with  numerous 
mural  pores  representing  aborted  buds. 

Family  1.     Favositidae    Milne  Edwards  and  Haime. 

Massive  or  branching  coralla.  Corallites  uniformly  prismatic,  toll  and  united  by 
their  walls,  which  are  perforated  by  large-sized  pores.  Septa  very  short,  usually 
represented  by  but  faintly  projecting  ridges  or  rows  of  spines,  but  seldom  completely 
absent.  Tabulae  numerous,  situated  at  regulär  intervals,  complete  and  horizontal, 
more  rarely  oblique  or  irregularly  vesicular  {^'  cystoid"). 

The  Favositidae  are  distinguished  from  the  Poritidae,  with  which  Verrill 
associates  them,  by  their  thick  solid  walls,  which  are  perforated  by  round, 
sometimes  tubiform  mural  pores.  The  corallites  are  usually  polygonal  in 
contour,  and  their  walls  exhibit  in  transverse  sections  a  dark,  or  sometimes 
light-coloured  median  line,  with  thickenings  of  stereoplasma  on  either  side 
(Fig.  176,  C).  The  family  is  exclusively  Paleozoic,  and  plays  an  important 
part  in  the  formation  of  Silurian,  Devonian  and  Carboniferous  coralline 
limestones. 

Favosites  Lam.  {Calamopora  Goldf.)  (Fig.  176).  Corallum  massive,  more 
rarely  branching.  Corallites  prismatic,  polygonal,  generally  hexagonal. 
Mural  pores  distributed  at  considerable  intervals.  Septa  very  faintly 
developed,  represented  by  longitudinal  ridges  or  rows  of  spines,  or  occasion- 
ally  obsolete.  Tabulae  numerous.  Ordovician  to  Carboniferous ;  very 
abundant  in  Silurian  and  Devonian. 

W.,  and  Wentzel,  J.,  The  Salt  Range  Fossils.  Palaeontol.  Indica,  18S7.—Beecker,  C.  U.,  The 
Development  of  a  Palaeozoic  Poriferous  Coral. — Symiiietrical  Cell  Development  in  the  Favositidae. 
Trans.  Conn.  Acad.,  1891,  vol.  viii.  —  Wentzel,  J.,  Zur  K(3untniss  der  Zoantharia  tabulata. 
Denkschr.  Akad.  "Wien,  1895,  vol.  \xü.—Sardeso7i,  F.  W.,  Über  die  Beziehungen  der  fossilen 
Tabulaten  zu  den  Alcyonarien.  Neues  Jahrb.  Mineral.,  1896,  Supplem.  vol.  x. —  Weissermel,  W., 
Sind  die  Tabulaten  Vorläufer  der  Alcyonarien?  Zeitschr.  deutsch,  geol.  Ges.,  1898,  vol.  1. — 
Vinassa  de  Regny,  P.  E.,  Trias-Tabulaten,  etc.  Res.  d.  wisseusch.  Erforsch,  des  Balaton-Sees, 
vol.  i.  pt.  1,     Badapesth,  1901. 

VOL.  I  I 


114 


COELENTERATA— ANTHOZOA 


PHYLÜM  II 


Columnopora  Nich.  {Calapoecia  Billings).  Like  the  preceding,  but  with 
numerous,  short,  well-marked  septa.  Mural  pores  large,  disposed  in  vertical 
rows  between  the  septa.     Ordovician. 


Fig.  17(3. 

Favosites  polymorpha  (Goldf.).  Devonian ;  Eifel.  A,  Coralluni,  natural  size.  B,  CoraUites  enlarged,  two 
of  them  broken  open  and  showing  tabulae.  C'and  D,  Transverse  and  longitudinal  sections  showing  spiniform 
septa  and  mural  pores  {p).    (C  and  B  after  Nicholson.) 


Emmonsia   E.    and 
Ordovician  (Trenton). 


H.     Ordovician    to    Carboniferous.     Nyctopora   Nich. 
Syringolites  Hinde.     Silurian  (Niagara). 

Pachypora  Lind.   (Fig.  177).       Corallum  branch- 

«-— «^»^  ing,  composed  of  prismatic,  polygonal  corallites, 
^  ySKmJIm  *^®  walls  of  which  are  so  thickened  towards  their 
VU/^Mf  mouths  by  layers  of  stereoplasma  that  the  calices 
wMyRjfc  appear  to  have  circular  contours.  Septa  very 
minute ;  mural  pores  scanty,  but  often  of  large  size. 
Abundant  in  Silurian  and  Devonian. 

Trachypora  E.  and  H.     Dendroid  with  cylindrical 
stems.     Corallites  polygonal ;  walls  so  thickened  by 
layers  of  stereoplasma  that  the  calices  become  round 
and  greatly  contracted,  and  appear  to  be  superficially 
widely  separated.     Mural  pores  few  and  irregularly 
distributed.     Septa  represented   by  rows  of  spines. 
Tabulae  at  remote  intervals.     Common  in  Devonian. 
Striatopora  Hall  (Fig.   178).      Like  the  preceding,  but  with    tubes    con- 
tracted   by    stereoplasma    at    a  greater  depth,   so  as  to  give    the   calices    a 
funnel-shaped  appearance.     Silurian  and  Devonian. 

Alveolites  Lam.  (Fig.  179).  Corallum  massive  or 
branching,  composed  of  small,  contiguous,  compressed, 
thin-walled  corallites,  with  obliquely  opening  triangulär 
or  semilunar  calices.  Septa  very  faint,  represented 
merely  by  ridges  or  rows  of  spinules,  sometimes  but 
a  Single  row  present.  Mural  pores  of  large  size,  ir- 
regularly distributed.  Very  common  in  Silurian  and 
Devonian. 

öladopora  Hall ;  Coenites  Eichw.      Silurian  and  Devonian. 

Pleurodidyum  Goldf.  (Fig.  180).       Corallum  depressed,  discoidal,  circular 


Fig.  177. 

Fachypora  nicholsoni  Frech. 
Middle  Devonian;  Eifel.  A, 
Transverse  section.  B,  Longi- 
tudinal section,  enlarged  ;  p, 
Mural  pores  (after  Nicholson). 


Fig.  178. 

Striatopora  flexnosa  Hall. 
Silurian  (Niagara) ;  New 
York. 


SUBCLASS  III 


TABULATA— FAVOSITIDAE 


115 


or  elliptical  in  contour,  lower  surface  covered  with  concentrically  striated 
epitheca,  and  frequently  a  foreign  vermiform  body  occupying  the  ceiitre  of  the 
base.  Corallites  small,  polygonal,  contracted  inferiorly  so  as  to  become 
funnel-shaped.      Septa    represented    by    faint    marginal    ridges,   or    obsolete. 


Fig.  179. 

A,  Alveolites  suborhicukiris  L&m.  Middle  Devonian ;  Gerolstein,  Eifel. 
Natural  size.  B  and  (',  Alveolites  lahechei  E.  and  H.  Silurian  (Wenlock) ; 
Ironbridge,  England.  Tangential  and  vertical  sections,  lo/j  (after  Nicholson). 


Fig.  180. 


Pleurodicty u  m  prohlemaiicum, 
Goldf.  Lower  Devonian  ;  Co- 
blenz.  Natural  size.  Vermiform 
foreign  body  in  the  centre. 


Walls  pierced  by  irregularly  distributed  mural  pores ;  tabulae  sparse. 
Devonian.  P.  prohlematicum  Goldfuss,  is  rather  abundant  in  the  Lower 
Devonian  "  Spirifera  sandstone  "  of  the  Eifel,  but  is  known  only  in  the  form 
of  casts.  In  these  the  walls  of  the  corallites  are  represented  by  narrow 
fissures  which  are  bridged  across  by  transverse  rods,  while  the  visceral  Chamber 
is  filled  up  with  sandstone,  P.  stylopora  Eaton,  from  the  Hamilton  Group  of 
North  America,  is  a  closely  related  species  and  also  possesses  the  vermiform 
body. 

Ä  B  C 


Fig.  181. 
Michelinia  fuvosa  de  Kon.     Carboniferous  Limestone  ;  Tournay,  Belgium.     A,  Corallum  fronl  above.     B, 
Lower  surface  with  radiciform  epithecal  processes.     C,  Vertical  section  (after  Gaudry). 


Michelinia  de  Kon.  (Fig.  181).  Discoidal  or  hemispherical  coralla,  often 
of  considerable  size,  and  covered  on  the  under  surface  with  concentrically 
striated  epitheca,  which  frequently  develops  hollow  radiciform  processes. 
Corallites  polygonal,  rather   large.     Septa  represented   by  numerous  longi- 


116 


COELENTERATA— ANTHOZOA 


FHYLUM  II 


tudinal  Striae  or  ridges  ;  mural  pores  irregularly  distribiited ;  tabulae  very 
numerous,  oblique  or  curved,  incompletely  developed,  and  usually  filling 
the  visceral  Chamber  with  loose  vesicular  tissue.  Devonian  and  Carboniferous. 
M.  favosa  de  Kon.,  extraordinarily  profuse  in  the  Lower  Carboniferous  Lime- 
stone of  Belgium. 


Family  2.      Auloporidae    Nicholson  (Tuhulosa  Milne  Edwards  and  Haime). 

Creeping,  hranching  or  reticulated  tubulo,r  coralla,  composed  of  cylindrical,  leaker 
or  trumpet-shaped  corallites,  with  thicJc,  imperforate,  wrinkled  walls.  Sepia  repre- 
sented  hy  faint  marginal  Striae ;  tahulae  moderately  numerous 
or  wanting.  Reprodudion  by  basal  or  lateral  gemmation. 
Ordovician  to  Carboniferous. 

Aulopora  Goldf.  (Fig.  182).  All  the  corallites  of  the 
prostrate  corallum  are  attached  by  the  whole  of  the  lower 
surface  to  some  foreign  object  (Alveolites,  other  corals,  or 
mollusks).  Tabulae  more  or  less  curved  ;  reproduction  by 
basal  gemmation.     Ordovician  to  Carboniferous. 

Cladochonus  M'Coy  (Fyrgia  E.  and  H.).  Corallum 
branching,  attached  only  at  isolated  points,  and  composed 
of  funnel-shaped  corallites  without  tabulae  and  septa. 
Reproduction  by  lateral  gemmation.     Carboniferous, 

Romingeria  Nich.  [Quenstedtia  Rom.).  Spreading, 
semi-erect,  bushy  coralla,  only  basally  attached,  and  with 
cylindrical  corallites  increasing  by  lateral  gemmation. 
Tabulae  moderately  numerous,  horizontal.  Silurian  and 
Devonian. 


Fig.  182. 


A  ulopora  t  ubaeformis 
Goldf.  Devonian  ;  Gerol- 
stein, Eifel.  Natural  size 
(after  Goldfuss). 


Family  3.     Syringoporidae  Milne  Edwards  and  Haime. 

Fasciculate  coralla  composed  of  cylindrical  corallites,  unifed  at  intervals  along  the 
sides  by  hollow  connecting  processes  or  hy  horizontal  expansions.  Walls  thicJc, 
wrinkled;  septa  faintly  developed,  represented  by  delicate 
ridges  or  longitudinal  rows  of  spinules  ;  tabulae  numerously 
developed,  usually  irregularly  funnel-shaped.  Reproduction 
by  basal  gemmation  or  by  buds  arising  from  the  connecting 
processes  and  horizontal  expansions.  Ordovician  to  Car- 
boniferous ;  maximum  in  Devonian  and  Carboniferous. 


Syringopora  Goldf.  (Fig.  183).  Fasciculate  coralla, 
often  attaining  considerable  size,  and  composed  of 
cylindrical,  thin-walled,  somewhat  flexuose  corallites; 
the  latter  communicate  by  means  of  hollow,  cylindrical, 
connecting  processes.  Septa  rudimentary ;  tabulae 
funnel-shaped.  Corallum  commencing  with  prostrate 
basal  zooids  similar  to  Aulopora.  Numerous  species 
ranging  from  Silurian  to  Carboniferous. 

Chonostegites  E.  and  H.  Corallum  massive  ;  cylindrical  corallites  connected 
by  horizontal,  hollow,  laminar  expansions  into  which  the  endothecal  tissues  are 
directly  continued  ;  tabulae  oblique,  cystoid.     Devonian. 


Fig.  183. 

Syringopora  ramulosa  Goldf. 
Carboniferous  Liinestone ; 
Regnitzlosau,  Fichtelgebirge. 
Natural  size. 


I 


Fia.  184., 


BCLAss  III  TABULATA— CHAETETIDAE  117 

Thecostegites  E.  and  H.  Corallum  encrusting  ;  corallites  short,  cylindrical, 
and  connected  by  thick  horizontal  plates.  Tabulae  approximately  horizontal ; 
septa  twelve  in  number,  represented  by  marginal  ridges.     Devonian. 

Family  4.     Halysitidae  Milne  Edwards  and  Haime. 
Chain  corals. 

Corallum  composed  of  long,  cylindrical,  laterally  compressed 
corallites,  which  are  joined  to  one  another  only  along  the  more 
restricted  edges,  and  form  free,  vertical,  intersecting  and  anas- 
tomosing  laminae.  Wall  thick,  covered  on  free  sides  by  wrinUed 
epitheca  ;  tabulae  numerous,  horizontal  or  concave  ;  septa  repre- 
sented by  vertical  ridges  or  rows  of  spines,  in  cycles  of  twelve, 
sometimes  entirely  absent.     Increase  by  stolonal  gemmation. 

The  unique  genus  Halysites  Fischer  (Catenipora  Lam.) 
(Fig.  184),  comprises  two  groups  of  species ;  those  in 
which  the  corallum  is  composed  throughout  of  coral- 
lites of  equal  size  (H.  escharoides  Lam.  sp.),  and  others  in 
which  any  two  of  the  larger  corallites  are  separated  by 
the  intervention  of  a  single  smaller,  closely  tabulate  tube  ,    . 

,  ^-r        ,  .     ^  .  \/^i-.  T   ri",       •  .  Halysites        catemilana 

{II.  catenmana  L\nn.  sp.)     Urdovician  and  JSilunan  ;  maxi-    (Linn.).     Siiurian  ;  Got- 
mum  in  the  Siiurian.  ^^"^-   Natural  size. 

Family  5.     Chaetetidae    Milne  Edwards  and  Haime. 

Massive  coralla,  composed  of  fine,  subequal,  tubiform  corallites,  contiguous  on  all 
sides.  Calices  rather  irregulär  in  shape,  one  diameier  slightly  greater  than  the  other. 
Walls  thoroughly  amalgamated,  common  to  adjacent  corallites,  imperforate,  apparently 
composed  of  closely  arranged,  anJcylosed  vertical  columns,  which  terminale  at  the 
surface  in  hollow  prominences.  Septa  absent,  but  one  or  two  tooth-like  projections 
often  observable  in  sections.     Tabulae  horizontal,  remote  or  abundant. 

The  forms  belonging  to  this  family  are  extinct,  and  occur  chiefly  in  the 
Ordovician,  Siiurian,  Devonian  and  Carboniferous  Systems ;  but  a  few  are 
also  found  sporadically  in  the  Trias,  Jura  and  Cretaceous.  They  are  largely 
concerned  in  the  formation  of  Paleozoic  coral  reefs,  especially  during  the 
Carboniferous.  Milne  Edwards  and  Haime  regarded  them  as  Anthozoans, 
Rominger  and  Lindström  as  Bryozoans,  while  Dybowski  emphasised  their 
affinities  with  the  Favositidae.  By  Nicholson  they  were  assigned  to  the  Octo- 
coralla,  for  the  reason  that  the  corallites  frequently  exhibit  a  dimorphous 
character  the  same  as  in  Heliolites  and  Heliopora,  besides  agreeing  in  their 
microscopic  structure  with  Heliolites;  while  in  addition  they  possess  well- 
developed  tabulae  and  imperforate  walls.  Many  genera  and  species  formerly 
included  under  this  family  are  now  assigned  to  the  Bryozoa. 

Chaetetes  Fischer  (Figs.  184«,  1846).  Corallites  long,  thin-walled,  prismatic, 
polygonal,  all  of  one  kind,  and  multiplying  by  fission.  Uncompleted  fission 
of  the  tubes  often  indicated  in  section  by  tooth-like  projection  extending 
into  the  visceral  Chamber.  Walls  structureless,  without  dark  median  line  ; 
tabulae  complete,  remote.     Very  abundant  in  Lower  Carboniferous ;  found 


118 


COELENTERATA— HYDROZOA 


PHYLUM  II 


also  in  Lias  and  Upper  Jurassic.     C.  radians  Fisch.,  is  an  important  rock- 
builder    in    the    Russian    Lower    Car- 
boniferous,  especially  near  Moscow. 

Dania  E.  and  H.  Silurian.  Tetra- 
dium Dana.  Ordovician  and  early  Sil- 
urian. Pseudochaetetes  Hang.  Upper 
Jurassic;  Europe.  P. pohjporus  (Qaenst.). 


Fig.  184a. 

Chaetetes  septosus  Fleiii.  Lower  Car- 
boniferous ;  England.  A,  Transverse 
section  parallel  to  npper  surface.  B, 
Vertical  section  both  enlarged  ;  p,  Pro- 
jecting  spines  representing  uncompleted 
fission  (after  Nicholson). 


Fio.  184^. 

Chaetetes  radians  Fischer.  Lower  Carbon- 
iferous  ;  Moscow,  Russia.  Portion  of  longi- 
tudinally  fractnred  coralluni,  natural  size. 


Geological  Range  of  the  Tabulata. 

With  but  few  exceptions  the  Tabulata  are  restricted  to  Paleozoic  for- 
mations,  and  from  the  Ordovician  to  the  Carboniferous  Systems  inclusive 
occur  in  considerable  profusion,  being  associated  with  the  Tetracoralla  and 
certain  Hydrozoa  (Stromatoporoids)  in  the  building  of  large  coral  reefs.  Of 
the  various  families  constituting  this  group,  the  systematic  position  of  which  is 
uncertain,  the  Halysitidae  are  limited  to  the  Ordovician  and  Silurian,  and  the 
remainder,  including  the  genus  Chaetetes  Fischer,  are  represented  continuously 
from  the  Ordovician  to  the  Carboniferous.  In  the  Middle  Cambrian  shales 
of  British  Columbia,  Walcott  has  recently  discovered  a  remarkably  well- 
preserved  actinian,  named  Mackenzia,  which  appears  to  belong  to  the  family 
Edwardsiidae,  and  to  be  closely  related  to  the  genus  Edwardsia. 


Class  2.     HYDROZOA    Huxley.     Hydroids  and  Medusae.i 

Sessile  or  free-swimming  polyps  or  polyp  Stocks,  without  oesophageal  tube,  and  with 
simple  gastrovascular  cavity  not  divided  into  radial  pouches. 

The  Hydrozoans  are  organisms  which  rarely  secrete  hard  parts,  and  hence 
are  ill-adapted  for  preservation  in  the  fossil  state.  The  ramifying  polyp  Stocks 
are  usually  inferior  in  size  to  those  of  the  Anthozoa,  and  possess  always  a 
simpler  structure ;  dimorphism  or  polymorphism  is,  however,  exhibited  by  the 
difFerent  individuals,  some  of  which  perform  solely  vegetative,  and  others  only 
reproductive  or  protective  functions.  Of  great  interest  is  the  prevailing  alterna- 
tion  of  generations,  in  which  process  fixed  polyp  Stocks  give  rise  to  a  generation 
of  free-swimming  Medusae,  the  eggs  of  which  develop  in  turn  into  polyps. 

1  Huxley,  T.  II.,  The  Oceanic  Hydrozoa.  London,  1859. — Agassiz,  A.,  North  American  Aca- 
lephae.  111.  Cat,  Museum  Comp.  Zool.  Cambridge  ii.,  1865. — Ilincks,  T.,  Natiiral  History  of  the 
British  Hydroid  Zoophytes.  London,  1868. — Claus,  C,  Untersuchungen  über  die  Organisation,  etc., 
der  Medusen.     Leipzic,  1883. 


I.^„ 


HYDROMEDUSAE 


119 


The  Ilydrozoa  are  all  aquatic,  and  with  few  excepfcions  are  inhabitants  of 
the  sea.  They  are  commonly  divided  into  the  two  following  sub-classes  : — 
Hydromedusae  and  Acalephae. 

Subclass  1.     HYDROMEDUSAE    Vogt. 

Sessile  or  free-swimming,  usually  hranching  colonies,  with  dimorphic,  nutritive  and 
reprodudive  polyps  ;  the  latter  frequently  become  liberated  in  the  form  of  small,  free- 
swimming  Medusae,  with  non-lobate  umbrellas  composed  of  a  hyaline,  gelatinous 
substance. 

Six  Orders  af  Hydromedusae  are  recognised :  Hydrariae,  Hydrocorallinae, 
Tubulariae,  Campanidariae,  Trachymedusae  and  Siphonophorae.  Of  these  only 
the  Hydrocorallinae,  Tubulariae  and  Campanulariae  secrete  calcareous  or 
chitinous  structures  capable  of  preservation  in  the  fossil  State. 


Order  2.     HYDROCORALLINAE   Moseley.i 

Naked  polyps  secreting  at  the  base  a  dense  calcareous  skeleton,  traversed  at  intervals 
by  two  series  of  vertical  tubes,  into  which  the  dimorphic  zoöids  can  be  retracted. 

The  Hydrocorallinae  comprise  the  two  Recent  groups  Milleporidae  and  Stylas- 
teridae,  which  were  univereally  regarded  as  true  corals  until  Louis  Agassiz  and 
Moseley  proved  their  relation- 
ship  to  the  Hydrozoa. 

Millepora  Linn.  (Fig.  185). 
Massive,  foliately  expanded, 
encrusting  or  branching  poly- 
paria  (coenosteum),  often  attain- 
ing  considerable  size.  Upper 
surface  punctured  by  round 
openings  of  the  larger  tubes 
(gastropores),  between  which 
are  the  mouths  of  numerous 
smaller  tubes  (dactylopores). 
The  skeleton  is  composed  of 
a  network  of  anastomosing 
calcareous  fibres,  traversed  by 
a  System  of  tortuous  canals. 
The  gastropores  lodge  the  larger,  nutritive  polyps,  and  the  dactylopores  the 
smaller,  food-procuring  zooids  ;  the  latter  have  no  mouths,  but  are  provided 
with  short,  clavate  tentacles  on  their  sides,  and  their  tubes  communicate  with 
the  vermiform  canals.  Zooidal  tubes  tabulate,  but  nonseptate.  The  genus 
is  an  important  reef-builder  of  the  present  day,  but  occurs  only  sparsely  in 
the  fossil  State.     Earliest  known  forms  appear  in  the  Eocene. 

1  Literature  :  Allman,  J.  G.,  Moiiograph  of  the  Gymnoblastic  or  Tubularian  Hydroids.  Ray 
Society,  1871-72. — Moseley,  II.  N..  Philosopliical  Transactions  Royal  Society,  vol.  167,  1878, — 
Steinmann,  G.,  Über  fossile  Hydrozoen  aus  der  Familie  der  Coryniden.  Palaeontographica,  vol. 
XXV.,  1877. — Idem,  Über  triasische  Hydrozoen  vom  östlichen  Balkan.  Sitzber.  Akad.  Wiss. 
Wien,  math. -phys.  Classe,  vol.  cii.,1893. — Canavari,  M.,  Idrozoi  Titoniani  appartenanti  alla  Faraiglia 
delle  Ellipsactinidi.  Mem.  Comitato  Geol.  vol.  iv.,  1893. —  Vinassa  de  Regny,  0.  A'.,  Studii  sulle 
Tdractinie  fossili.      Mem,  Accad.  dei  Lincei,  1899,  ser.  6,  vol.  iii. 


Fio.  185. 

Millepora  nodosa  Esp.  Receiit.  A,  Upper  surface  of  coeno- 
steum, showing  gastropores,  k,  and  dactylopores  c,  -lo/j.  B, 
Vertioal  section,  k,  gastropores  with  tabulae,  t ;  c,  Vermiform 
canals  communicating  with  dactylopores,  80/j  (after  Steinmann). 


120 


COELENTERATA— HYDEOZOA 


PHYLUM  II 


Stylaster  Gray.  Branching  polyparia  composed  of  a  network  of  fibrous, 
rose-coloured  coenenchyma,  in  which  are  situated  calicular  depressions  that  are 
provided  with  pseudosepta  and  columellae,  and  communicate  with  the  zooid 
tubes  and  vermiform  canals.     Recent,  and  occurring  sparsely  in  the  Tertiary. 


Order  3.     TUBULARIAB  AUman. 

Polyp  Stocks  which  are  either  nahed  or  covered  with  chitinous  outer  layer  (periderm). 
Both  the  polypoid  nutritive  zooids,  and  also  the  medusoid  reproductive  animals  are 
without  cup-shaped  hydrothecae  surrounding  the  polyp  head.  A  chitinous  or  calcareous 
skeleton  (hydrophyton)  is  frequently  secreted  at  the  hase. 


Hydractinia  v.  Bened.  (Fig.  186).  Hydrophyton  in  the  form  of  encrusting, 
chitinous,  rarely  calcareous  expansion,  frequently  investing  gastropod  shells. 
The  crust  consists  of  successive,  slightly  separated,  horizontal  laminae,  which 


l 


^- 


are  supported  by  num- 
erous  vertical  rods  or 
columns  {radial  pillars). 
The  surface  is  covered 
with  projecting  hollow 
spines  and  tubercles, 
and  is  also  traversed 
by  shallow,  branching 
grooves  {astrorhizae). 
Interlaminar  spaces 
communicating  with 
the  surface  by  means 
of  rounded  tubes. 
Tertiary  and  Recent. 

Ellipsactinia  Steinm. 
Hydrophyton  irregu- 
larly  ellipsoidal,  com- 
posed of  thick,  con- 
centric,  slightly  separ- 
ated, calcareous  lam- 
ellae,  which  are  united 
by  sparsely  distributed 
vertical  columns. 
Lamellae  are  formed  by  the  anastomosis  of  exceedingly  delicate  calcareous 
fibres,  punctured  by  numerous  fine  radial  tubes,  and  furnished  on  both  sides 
with  pits,  tubercles  and  branching  furrows.  Upper  Jurassic  (Tithonian)  ; 
Alps,  Carpathians  and  Apennines. 

Sphaeractinia  Steinm.  Like  the  preceding,  but  composed  of  thin,  widely 
separated  lamellae,  which  are  supported  by  numerous  radial  pillars.  Centre 
frequently  occupied  by  a  foreign  body.     Upper  Jurassic  (Tithonian). 

Loftusia  Brady  (Fig.  187).  Ellipsoidal  or  fusiform  bodies,  composed  of 
thin,  concentric  or  spirally  rolled  calcareous  lamellae.  Interlaminar  spaces 
wide,  intersected  by  numerous  radial  pillars,  and  often  secondarily  filled  with 
calcareous  mud.     Eocene  ;  Persia. 

Parkeria  Carp.     Globular   or  walnut  -  shaped   organisms    with    nodulated 


Fig.  186. 

A,  Hydractinia  echinata  F\em.  Recent;  North  Sea.  Portion  of  commensal 
colony,  greatly  enlarged  ;  hy,  Polyps  (hydranths) ;  go,  Generative  buds  (gono- 
phores) ;  hph,  Hydrophyton  adherent  to  shell  of  Buccinium  undatum,  and 
showing  reticulated  structure  in  vertical  section.  B,  Hydractinia  calcarea 
Gart.  Vertical  section  of  hydrophyton,  greatly  enlarged  (after  Carter) ;  a, 
Primary  basal  lainella  ;  h,  Interlaminar  space  ;  c,  Second  lamella  ;  d,  Radial 
pillars  between  the  lamellae  ;  e,  f,  Tubercles  and  spines  projecting  on  upper 
snrface.  C,  Hydractinia  pliocaena  Allm.  Pliocene ;  Asti,  Italy.  Hydro- 
phyton encrusting  on  Nassa  shell  (natural  size).  D,  Portion  of  magnified 
surface  of  the  latter,  showing  branching  grooves  and  wart-like  tubercles. 


CLASS  II 


TUBULARIAE 


121 


exterior,  and  composed  of  rather  thick,  concentric,  calcareous  lamellae.  Inter- 
laminar Spaces  divided  into  chamberlets  by  stout  radial  pillars,  which  usually 
extend  continuously  through  a  number  of  lamellae.  Both  lamellae  and  pillars 
consistof  minutely  tabulated  tissue,  the  tubules  of  which  are  radial  in  arrange- 
ment.  Centre  frequently  occupied  by  a  foreign  body.  Cambridge  Greensaiid 
(Cenomanian). 

The  genera  Parkeria  and  Loftusia  were  originally  described  as  agglutinated 
Foraminifera  ;  they  are,  however,  manifestly  very  closely  allied  to  Ellipsaäinia 
and  Sphaeractinia. 

Porosphaera  Steinm.  (Fig.  188).  Globular  masses  of  the  size  of  peas  or 
hazel-nuts  frequently  growing  around  some  foreign  body,  and  composed  of 
anastomosing  calcareous  fibres  which  are  penetrated  by 
numerous  radial  tubules ;  the  latter  open  on  the  surface 
in  the  form  of  large  pores,  around  which  radial  or  stel- 
late  furrows  (astrorhizae)  are  sometimes  grouped.  Upper 
Cretaceous. 


Fio.  187. 


Fig.  188. 

Porosphaera  glöbularis 
(Phill.).  Upper  Cretace- 
ous ;  Rügen.  A,  Skeleton, 
natural  size ;  l,  Cavity 
originally  occupied  by 
foreign  body,  B,  Trans- 
verse    section     showing 

Loftusia  persiraBrady.  Eocene  ;  Persia.  yl,  Specimen  cut  open  to  showgeneral  radial  tubes  of  gastro- 
structure,  natural  size  (after  Brady).  B,  Section  showingitwo  lamellae  and  inter-  pores,  2/j  (after  Stein- 
laminar Alling,  greatly  enlarged.  mann). 

Stoliczkaria  Duncan.     Trias  ;  Karakoram  and  Balkan  Mountains. 

Cydoporidium,  PMzoporidium  Parona.  Cretaceous.  Poraäinia  and  Cyclac- 
tinia  (Kerunia  Mayer-Eymar)  Yinassa.     Tertiary. 

Heterastridium  Reuss  (Syringosphaeria  Duncan).  Includes  spheroidal,  nodular 
bodies  of  considerable  size,  composed  of  slender,  anastomosing,  and  more  or 
less  distinctly  radial  calcareous  fibres.  Skeleton  comparatively  dense,  but 
perforated  by  two  series  of  zooidal  tubes  appearing  superficially  as  pores.  The 
apertures  of  the  larger  tubes  are  round,  those  of  the  smaller  stellate,  and  are 
surrounded  by  radial  furrows.      Alpine  Trias. 


Appendix  to  the  Hydrocorallinae  and  Tubulariae. 

Stromatoporoidea  Nicholson  and  Murie.^ 

Closely  allied  to  the  Hydrocorallinae  and  Hydractinia  are  the  extinct  Stromato- 
poroidea, which  combine  in  many  respects  the  characters  pertaining  to  both  of 

^  Bargatzki,  A.,  Die  Stromatoporen  des  rheinischen  Devons.  Bonn,  1881. — Nicholson,  H.  A., 
Monograph  of  the  British  Stromatoporoids.  Palaeont.  Soc.  1886-92.— (Jir^y,  G.  H.,  Revision  of 
the  Sponges  andCoelenterates  of  the  Lower  Helderberg  Group  of  New  York.  14th  Ann.  Rept.  N.Y. 
State  Geol.,  I^'d^.  —  Tornquist,  A.,  Über  mesozoische  Stroniatoporiden.  Sitzber.  preuss.  Akad. 
Wiss.,  1901,  vol.  xlvii.  —  Yabe,  H.,  On  a  Mesozoic  Stromatopora.  Jouru.  Geol,  Soc.  Tokyo,  1903, 
vol.  X. — Beninger,  K.,  Einige  neue  Tabulaten  und  Hydrozoen  aus  mesozoischen  Ablagerungen. 
Neues  Jahrb.    f.    Mineral,   i.,    190Q.—Rothpletz,   A.,   Über  Algen  und   Hydrozoen  im  Silur  von 


122 


COELENTERATA— HYDEOZOA 


PHYLUM  II 


the  above-named  groups,  but  whose  exact  position  in  the  zoological  System 
remains  as  yet  uncertain.  During  the  Paleozoic  era,  to  which  they  are  con- 
fined,  the  Stromatoporoids  were  important  geological  agents,  whole  beds  of 
limestone  being  often  essentially  constituted  of  their  remains.  In  the  Mesozoic 
era  they  are  replaced  by  very  closely  allied  forms  of  Hydradinia,  which  in  all 
probability  represent  their  immediate  descendants. 

The  Stromatoporoids  secrete  hemispherical,  globiüar,  nodular  or  hori- 
zontally  expanded  skeletons,  which  are  sometimes  encrusting,  sometimes 
attached  by  a  short  basal  peduncle,  and  are  covered  on  the  under  side  with 
concentrically  wrinkled  epitheca,  while  the  apertures  for  the  emission  of  the 
polyps  are  situated  on  the  upper  surface.  The  general  tissue  of  the  coenosteum 
is  composed  of  numerous,  concentric,  undulating,  calcareous  layers  or  laminae, 
which  are  separated  by  narrower  or  wider  interlaminar  Spaces,  but  are  at  the 
same  time  connected  by  numerous  vertical  rods  {radial  pillars).  The  pillars 
as  well  as  the  laminae  are  traversed,  as  a  rule,  by  minute,  irregularly  directed 
j  ß  canaliculi.        In    some 

genera  the  coenosteum 
is  provided  with  verti- 
cal tabulate  tubes, 
which  most  probably 
served  for  the  recep- 
tion  of  the  polyps,  as 
in  the  genus  Millepora ; 
but  in  many  instances 
they  are  wanting.  The 
surfaces  of  the  laminae 
typically  exhibit  pores 
and  small  tubercles, 
and  frequently  also 
shallowstellate  furrows 
(astrorhizae),  which  radiate  outwards  from  numerous  centres.  Sometimes  the 
laminae  consist  merely  of  a  loose  network  of  horizontal  calcareous  fibres. 

Goldfuss  at  first  held  the  Stromatoporoids  occurring  so  profusely  in  the 
Eifel  for  corals  (Millepora),  and  subsequently  for  sponge-like  zoophytes ;  while 
von  Rosen  considered  them  as  horny  sponges  that  had  become  secondarily 
calcified.  Sandberger  and  F.  Roemer  assigned  them  to  the  Bryozoans ; 
Dawson  to  the  Foraminifera ;  Sollas  to  the  siliceous  sponges  {Hexacünellida)  ; 
and  Salter  to  the  calcareous  sponges,  whose  example  Nicholson  also  followed. 
Lindström,  Carter  and  Steinmann  subsequently  pointed  out  their  relations 
to  Hydradinia  and  Millepora ;  and  Nicholson  and  Murie  came  finally  to 
regard  them  as  a  group  of  extinct  Hydrozoans  allied  to  Hydradinia  on  the 
one  band  (Actinostromidae),  and  Millepora  on  the  other  (Stromatoporidae 
and  Idiostromidae). 

Adinostroma  Nich.  (Fig.  189).  Skeleton  having  vertical  or  radial  pillars 
disposed  at  tolerably  regulär  intervals,  and  extending  continuously  through  all 

Gotland  und  Ösel.  K.  Svenslc.  Vetensk.  Akad.  Handl.,  1908,  vol.  xliii. — Gürich,  G.,  Les  Spongio- 
stromides  du  Visedansle  Province  de  Namur.  Mein.  Mus.  Roy.  d'Hist.  Nat.  Belg.,  1906,  vol.  iii. 
— Idem,  Neues  Jahrb.  f.  Mineral.,  1907,  i. — Parona,  C.  F.,  La  Fauna  coralligena  del  Cretaceo  dei 
Monti  d'  Ocre  nell'  Abruzzo  Aquilano.  Mem.  Conim.  Geol.  Ital.,  1909,  vol.  w.— Parks,  W.^A.,  The 
Stromatoporoids  of  the  Guelph  Formation  in  Ontario  ;  the  Niagara  ;  the  Silurian  of  America  ;  the 
Ordovician.     Univ.  of  Toronto  Studies,  Nos.  4-7,  1907-1910. 


Fig.  189. 

Actinostroma  intertextum  Nich.  Silurian  (Wenlock)  ;  Shropshire.  A, 
Tangential  section  showing  radial  pillars  and  reticulated  structure  of  con- 
centric laminae.  B,  Vertical  section,  showing  formation  of  laminae  from 
processes  given  off  horizontally  by  radial  pillars,  12/1  (after  Nicholson). 


|^p>ASS  II 


STROMATOPOROIDEA 


123 


or  at  least  a  considerable  number  of  laminae ;  in  vertical  sections,  accordingly, 
exhibiting  a  quadrate  meshwork.  The  laminae  consist  of  an  anastomosing 
network  of  calcareous  fibres,  generally  having  a  porous  structure;  their  surfaces 
are  covered  with  projecting  granules  or  tubercles,  which  represent  the  free 
Upper  ends  of  the  vertical  pillars.     Rare  in  the  Silurian,  but  very  abundant 


Fic.  l'JO. 

Stromatopora  tuberculata   Nich. 
(Corniferous     limestone) ;     Jarvis, 
Natural  size  (after  Nicholson). 


Devon  ian 
Ontario, 


Fin.  191. 


Cmmopora  placenta  Phill.      Devonian  ;  Torquay, 
Devonshire.     A,   Tangential  section,   natural  size. 

B,  The  same,  highly  magnified  ;  a,  Vertical  "  Cauno- 
pora  tube  "  ;  h,  Canal  partially  cut  into ;  c,  Calcare- 
ous fibres  traversed  by  delicate  ramifying  canaliculi. 

C,  Vertical  section,  highly  magnified. 


in  Devonian  of  the  Eifel,  England  and  North  America.       A,  clathratum  Nich. 
{  =  Stromatopora  concentrica  p.  p.,  Goldf.). 

Clathrodidyon  Nich.  Like  the  preceding,  but  with  radial  pillars  extending 
only  between  the  upper  and  lower  surfaces  of  successive  laminae.  Character- 
istic  of  Silurian  ;  rare  in  Devonian. 

Stromatopora  Goldi.  emend.  Nich.  (Pachystroma  ^ich.  and  Murie)  (Fig.  190). 
Radial  pillars  uniting  with  the  thick  concentric  strata  or  latilaminae  to  form  a 
finely  reticulated  tissue,  in  which  tabulate  zooidal 
tubes  are  sparsely  distributed.  Plentiful  in  Devon- 
ian ;  less  common  in  Silurian. 

Caunopora  Lonsdale  (Fig.  191),  and  Diapora 
Bargat.,  are  Stromatoporoids  which  are  indis- 
tinguishable  from  other  genera  except  by  the 
presence  of  numerous  definitely  walled  tubes  pene- 
trating  the  coenosteum  at  closer  or  remoter  in- 
tervals.  The  tubes  are  often  thick-walled,  are 
furnished  with  horizontal  or  funnel-shaped  tabulae, 
and  occasionally  with  septal  spines ;  in  many  cases 
they  evidently  represent  the  corallites  of  Aulopora 
and  Syringopora  colonies,  which  have  become  en- 
veloped,  but  have   continued   to  live  commensally 

within  the  tissues  of  the  Stromatoporoid.      In  other  cases,  however,  the  tubes 
appear  to  have  been  formed  by  true  Stromatoporoid  polyps.     Devonian. 

Hermatostroma  Nich.  (Fig.  192).  Massive  or  foliaceous  skeletons,  composed 
of  thick  parallel  latilaminae,  connected  by  vertical  pillars  ;  pillars  often  running 
continuously  through  several  concentric  laminae.  Roth  pillars  and  laminae 
exhibit  a  dark  median  line  when  viewed  in  cross-section,  indicating  either  the 
presence  of  axial  canals  or  composition  out  of  two  lamellae.     Devonian. 


Fio.  192. 

Hermatostroma  sp.  ind.  Devonian ; 
Torquay,  Devonshire.  a,  Hori- 
zontal lamina  composed  of  two 
slightly  separated  lamellae ;  b, 
Interlaminar  chamberlet ;  c,  Radial 
pillar  traversed  by  axial  canal. 


124  COELENTERATA— HYDROZOA  phylüm  ii 

Idiostroma  Winch.  Coenosteum  cylindrical  or  fasciculate,  traversed  by 
axial,  tabulate  zoöidal  tubes,  which  give  off  secondary  lateral  tubes.  General 
tissue  reticulated,  similar  to  Stromatopora.     Devonian. 

Labechia  E.  and  H.    Ordovician  and  Silurian  ;  North  America  and  Europe. 

Stylodidyon,  Stromatoporella  and  Syringostroma  Nich. ;  Amphipora  Schulze  ; 
Stachyodes  Bargat.     Devonian  of  Europe  and  North  America. 

A  number  of  genera  are  described  by  Waagen  and  Wentzel  from  the 
Permo-Carboniferous  rocks  of  Farther  India,  such  as  Carterina,  Disjedopora, 
Circopora,  etc.  Probably  in  the  same  neighbourhood  should  be  placed  several 
peculiar  encrusting  marine  forms  from  the  Carboniferous  of  Belgium,  described 
by  Gürich  under  the  names  of  Aphrostroma,  Spongiostroma,  Chondrostroma, 
Malacostroma,  etc.  The  first-named  of  these  occurs  also  in  the  Silurian  of 
Gotland,  and  was  associated  by  Gürich  with  the  Foraminifera. 


Order  4.     CAMPANULARIAB  AUman. 

(Leptomedusae,  Calyptohlastea  Allman  ;  Thecaphora  Hincks). 

Delicate,  branching,  plant-like,  sessile  coloiiies,  with  chitinous  periderm  enveloping 
the  base,  pedunde,  and  also  the  cup-like  receptades  (hydrothecae)  which  endose  the 
individual  polyps.  The  proliferous  zooids  are  developed  within  urn-shaped  capsules 
(gonothecae)  of  comparatively  large  size,  and  sometimes  become  separated  off  as  free- 
swimming  velate  Medusae. 

Recent  Campanularians,  such  as  are  comprised  by  the  families  Sertularidae, 
Plumularidae  and  Campanularidae  possess  durable  hard  parts,  but  nevertheless 
their  remains  have  not  as  yet  been  found  in  the  fossil  State,  with  the  exception 
of  a  few  forms  from  Pleistocene  deposits. 

Range  and  Distribution  of  the  Hydromedusae. 

Of  those  members  of  this  group  in  which  the  preservation  of  structural 
parts  is  at  all  possible,  the  Hydrocorallinae  have  been  recognised  with 
certainty  as  early  as  the  Upper  Cretaceous.  During  the  Tertiary  they 
became  more  widely  distributed,  and  at  the  present  day  are  important  reef- 
builders. 

During  the  Upper  Jura,  and  notably  in  Tithonian  beds  of  the  Mediter- 
ranean  region,  certain  genera  of  the  Hydractinidae  {Ellipsadinia,  Sphaeradinia) 
are  abundantly  represented.  Contrariwise,  other  Tubularians,  such  as  the 
Triassic  Heterastridium,  and  Parkeria  and  Porosphaera  from  the  Cretaceous  of 
central  Europe,  occur  only  sparsely. 

The  extinct  organisms  known  as  Stromatoporoids  were  extremely 
important  rock-builders  during  the  Paleozoic,  much  of  the  limestone  of  the 
Silurian  and  Devonian  Systems  resulting  from  the  destruction  of  the  reefs 
built  by  these  fossils.  Their  massive  Stocks  sometimes  attain  gigantic  size. 
Stromatoporoid  remains  are  profusely  distributed  in  Ordovician  and  Silurian 
rocks  of  North  America,  England  and  Russia,  also  in  the  Middle  Devonian  of 
the  Eifel  and  Ardennes,  and  in  equivalent  strata  of  Nassau,  Devonshire,  the 
Urals,  Spain,  etc.  Except  for  a  few  rare  survivors,  the  group  does  not 
Continus  beyond  the  Paleozoic  era. 


CLASs  II  GKAPTOLITOIDEA  125 


■ 


Appendix  to  the  Hydromedusae. 

Olass  or  Subclass.      GRAPTOLITOIDEA  Lapworth.i 

{Rhabdophom  Allman.) 


Under  the  term  of  Graptolitoidea  are  included  organisms  which  have  been 
considered  by  various  authors  as  plant  remains,  horny  sponges,  Pennatulidae, 
Cephalopods  and  Bryozoans.  Portlock,  in  1843,  first  pointed  out  their 
analogy  with  the  Sertularians  and  Plumularians  ;  and  his  inferences  as  to 
their  genetic  relationship  were  afterwards  confirmed  by  the  painstaking 
researches  of  Allman,  Hall,  Hopkinson,  Lapworth,  Nicholson,  and  others. 
More  recently,  however,  their  kinship  has  been  denied  by  Neumayr  and 
Wiman,  who,  on  account  of  the  bilateral  symmetry  of  the  sicula  and  thecae, 
claim  that  Graptolites  cannot  be  included  within  any  of  the  now  existing 
classes  of  organisms. 

Graptolites  are  generally  found  in  an  imperfect  state  of  preservation,  lying 
flattened  in  the  same  plane  upon  the  slaty  laminae  in  which  they  are  embedded, 
and  associated  in  large  numbers.  More  rarely  they  occur  in  limestone,  when 
the  internal  cavities  are  filled  with  calcareous  matter,  and  the  original  form 
accurately  preserved.  Such  specimens  have  been  successfully  etched  out  and 
investigated  under  the  microscope  by  Holm  and  Wiman. 

The  general  skeletal  tissue  (periderm)  was  obviously  flexible,  and  composed  of 

^  Literature  :  Hall,  J.,  Palaeontology  of  New  York,  vols.  i.,  iii.,  1847,  1859. — Graptolites  of 
the  Quebec  Group.  Cauad.  Organic  Remains,  dec.  ii.  Geol.  Surv.  Cauad.,  1865. — lutroduction  to 
the  study  of  Graptolites.  20th  Ann.  Rept.  N.Y.  State  Gab.  Nat.  Hist.,  1868.— Barrande,  J.,  Grapto- 
lites de  Boheme.  Prague,  1850. — 8uess  E.,  über  böhmische  Graptolithen.  Haidinger's  Naturw. 
Abhandl.,  1851,  vol.  iv. — Scharenherg,  PF.,  Ueber  Graptolithen.  Breslau,  1851. — Geinitz,  H.  B., 
Die  Versteinerungen  der  Grauwackenformation  in  Sachsen,  Leipzic,  1852. — Die  Graptolithen  des 
mineral.  Museums  in  Dresden,  1890. — Richter,  R.,  Thüringische  Graptolithen.  Zeitschr.  Deutsch. 
Geol,  Ges.,  vols.  v.,  xviii.,  xxiii.,  1853,  '66,  71. — Nicholson,  II.  A.,  Monograph  of  the  British 
Graptolitidae,  1872. — Lapworth,  C,  Notes  on  the  British  Graptolites.  Geol.  Mag.,  vols.  x.,  xiii., 
1873,  '76.  Also  various  articles  in  Quart.  Journ.  Geol.  Soc,  1875,  '78,  '81,  and  Ann.  Mag.  Nat. 
Hist.,  1879,  '80.— On  the  Graptolites  of  County  Down.  Ann.  Rep.  Belfast  Nat.  Field  Club,  1877, 
vol.  i.,  pt,  iv, — Tullberg,  S.  A,,  On  Species  of  Didymograptus.  Geol.  För.  Stockholm  Förh,,  1880, 
vol.  v. — Spencer,  J.  W.,  Graptolites  of  the  Upper  Silurian  System.  Bull.  Mus.  Univ.  Missouri,  1884. 
— Tornquist,  S.  L.,  Observations  on  Graptolites.  Acta  Univ.  Lund,  1890-92,  vols.  xxvii.-xxix. — 
Holm,  G.,  Skandinaviens  Gi'aptoliter.  Svensk,  Vetensk.  Akad.  Förh.,  1881,  vol.  xxxviii. — Gotland's 
Graptoliter.  Bihang  Svensk.  Vetensk,  Akad.  Handl.  1890,  vol.  xvi. — Barrois,  C,  Memoire  sur  la 
distribution  des  graj)tolites  en  France.  Annales  Soc.  Geol.  Nord,  1892,  vol.  xx.— Wiman,  C,  Über 
Monograptus  und  Diplograptidae.  Bull.  Geol.  Inst.  Upsala,  1893,  vol.  i.  (English  translatiou  in 
Journ.  Geol.,  1893,  vol.  ii.). — Tornquist,  S.  L.,  Observations  on  the  Structure  of  some  Diprionidae. 
Fisiogr.  Sällsk.  Handl.,  1893,  '97,  vols.  iv.,  viii. — Researches  into  the  Graptolites  of  the  Scanian  and 
Vestrogothian  Phyllo-Tetragraptus  Beds.  Lunds  Univ.  Arsskrift,  1901,  vol.  xxvii. — Ferner,  J., 
liltudes  sur  les  graptolites  de  Boheme.  Prague,  1894-99. — Holm,  G.,  Om  Didymograptus,  Tetra- 
graptus  och  Phyllograptus.  Geol.  För.  Förh.,  1895,  vol.  xvii.  No.  164. — Ruedemann,  R.,  Synopsis  of 
the  Mode  of  Growth  and  Development  of  the  Genus  Diplograptus.  Amer.  Journ.  Sei.  (3),  1895,  vol. 
xlix.  ;  Also  in  Ann.  Rept.  N.Y.  State  Geol.  1894,  and  Amer.  Nat.,  1897,  vol.  xxxii. — Graptolites  of 
New  York,  N.Y.  State  Museum.  Memoirs  vii.  1904,  and  xi.,  1908. — Gurley,  R.  R.,  North  American 
Graptolites.  Journ.  Geol.,  1896,  vol.  iv. —  Wiman,  C,  Über  die  Graptolithen.  Bull.  Geol.  Inst. 
Up.sala,  1895,  vol.  ii.  ;  also  Nat.  Sei.,  1896,  vol.  ix.,  and  Bull.  Geol.  Inst.  Upsala,  1897,  No.  6. 1900, 
No.  10. — EUes,  G.  L.,  and  Wood,  E.  M.  R.,  Monograph  of  British  Graptolites,  ed.  by  C. 
Lapworth.  Palaeontogr.  Soc,  1901  to  date. — Hall,T.  S.,  Note  on  the  Distribution  of  the  Graptolitliidae 
in  the  Rocks  of  Castlemaine.  Rept.  Austral.  A.ssn.  Adv.  Sei.,  1894  ;  also  Proc.  Roy.  Soc.  Victoria 
1892,  '97,  '98,  '99  ;  Geol.  Mag,,  1899,  vol.  vi.—Roemer,  F.,  and  Frech,  F.,  Lethaea  Palaeozoica,  1897, 
vol.  i. — Bassler,  R.  S.,  Dendroid  Graptolites  of  the  Niagarau  Dolomites  at  Hamilton,  Ontario. 
Bull.  Smithson.  Inst.,  No.  65,  1909. —  Westergard,  A.  H.,  Studier  öfver  Dictyograptus.skiffern.  Med. 
fr.  Lunds  Geol.  Fält  Klub.  Ser.  B,  No.  4,  1909. 


126  COELENTERATA— HYDROZOA  phylum  ii 

smooth  or  fiiiely  striated  chitine  ;  usually  it  has  the  form  of  a  dense  continuous 
membrane,  but  in  the  Retiolitidae  it  is  attenuated  and  supported  by  a  latticed 
network  of  chitinous  threads.  It  is  usually  preserved  as  a  thin  bitumino- 
carbonaceous  film,  which,  however,  is  often  infiltrated  with  pyrites,  and  is  not 
infrequently  replaced  by  a  glistening  greenish-white  Silicate  (Gümbelite). 

The  Compound  organism  or  rhabdosome  ('^ polypary  ")  of  the  Graptolites  is 
usually  linear,  more  rarely  petaloid  in  form,  undivided  or  branching,  and  is 
either  straight,  beut,  or  in  exceptional  instances  spirally  enrolled.  These 
rhabdosomes,  each  of  which  originates  from  a  sicula  (see  below)  may  again  be 
united  into  colonies  of  a  higher  order  (synrhabdosome).  Cup-shaped  rhabdo- 
thecae,  which  are  usually  obliquely  set  and  more  or  less  overlapping,  are  borne 
on  one  or  on  both  sides  of  the  polypary,  and  are  united  by  a  common 
coenosarcal  canal  enclosed  in  the  /periderm.  The  polypary  is  in  later  forms 
strengthened  by  a  peculiar  chitinous  axis  (virgula,  solid  axis),  which  in  the 
Monograptidae  runs  in  a  groove  lying  outside  the  coenosark  on  the  dorsal  side 
of  the  organism  {i.e.  on  the  side  opposite  to  the  theciferous  margin).  But  in 
the  biserial  Graptolites  the  virgula  is  either  enclosed  between  the  laminae  of 
a  central  or  sub-central  septum,  which  is  formed  by  the  coalescence  of  the 
flattened  dorsal  walls  (Biprionidae) ;  or  it  is  double  and  the  two  virgula  (see 
text  Fig.  209)  are  placed  on  opposite  sides  of  the  coenosark,  and  are  united  with 
the  peridermal  network  {Retiolitidae). 

Springing  from  the  common  canal,  is  a  series  of  thecae  {celhles,  denticles),  which 
are  disposed  in  longitudinal  rows  along  either  one  (Fig.  193),  two  (Fig.  194) 
or  four  sides  of  the  polypary.  They  usually  have  the  form  of  elongated, 
cylindrical,  rectangular  or  conical  sacs;  their  walls  are  in  most  cases  applied 
to  those  of  their  neighbours  above  and  below,  although  occasionally  they 
spring  out  quite  isolated  from  one  another.  Each  theca  opens  directly  into 
the  common  canal,  and  is  furnished  distally  with  an  external  aperture,  the 
form  and  size  of  which  vary  extremely  in  difFerent  species.  In  some  forms  it 
is  circular  or  quadrate  or  introverted  or  introtorted  ;  in  others  it  is  contracted. 
Not  infrequently  the  outer  lip  is  ornamented  with  one  or  two  slender  spines, 
which  often  subdivide  and  inosculate  with  one  another.  The  form  of  the 
thecae  and  apertures  has  been  employed  by  Lapworth  to  define  families  and 
subfamilies. 

The  polypary  in  most  Graptolites  is  furnished  at  its  proximal  end  with  a 
minute,  triangulär  or  dagger-shaped,  originally  conical,  body  called  the  sicula 
(Fig.  195),  which  represents  the  original  embryonic  skeleton  and  is  suspended 
from  an  originally  tubulär  filament,  the  7iema  oy  nemacaulus  {Fig.  196).  In  the 
wall  of  the  sicula  is  formed,  in  the  later  Graptolites,  an  axis  or  rod,  the 
virgula,  which  extends  through  the  rhabdosome.  Rhabdothecae  are  then 
budded  either  uniserially  along  one  side,  or  in  alternate  sequence  along  both  of 
the  lateral  margins  of  the  sicula,  originating  from  one  theca  near  the  major  end 
of  the  sicula.  They  grow  either  laterally  away  from  the  sicula  (Axonolipa)  or 
along  the  nemacaulus  (Axonophora).  The  sicula  itself  ceases  to  grow,  as  a 
rule,  after  the  first  thecae  are  budded,  and  sometimes  it  becomes  obsolete  or 
absorbed.  Sometim^es  the  rhabdosome  remains  undivided,  sometimes  it  forms 
branches,  which  may  diverge  at  various  angles  ;  in  other  cases  two  or  four 
uniserial  polyparies  may  be  placed  back  to  back  with  their  dorsal  walls 
coalescing,  thus  giving  rise  to  di-  or  tetra-serial  colonies.  In  the  latter  types 
the  coenosarc  is  commonly  divided  by  one  or  two  median  septa. 


I 


GRAPTOLITOIDEA 


127 


Graptolites  commonly  occur  in  argillaceous  schists,  moie  rarely  in  limestone 
formations,  of  the  Upper  Cambrian,  Ordovician  and  Silurian  Systems.  They 
seem  to  have  swarmed  in  the  muddier  portions  of  the  sea,  and  floated  either 
attached  to  sea-weeds,  etc.,  or  as  free-swimming  colonies  ;  or,  in  rarer  instances, 
remained  stationary  with  the  sicula  or  a  root  embedded  in  the  mud,  or  attached 
to  foreign  bodies.  They  are  divided  into  two  Orders :  Dendroidea  Nicholson 
{Cladophom  Hopkinson),  and  Graptoloidea  Lapworth,  or  Graptolites  proper.     The 


:^"^?- 


Fig.  195. 

a,  Münograptus  gregarius  Lapw.  Sil- 
urian ;  Dobbs,  Linn,  Scotland.  Proxiinal 
end  showing  sicula,  enlarged  ;  b,  Didy- 
mograptus  pennatulus  Hall.  Ordovician 
(Quebec  Group) ;  Point  L6vis,  Canada. 
Proximal  end  .showing  sicula,  enlarged 
(after  Lapworth). 


Fig.  193. 

A,  C,  Monograptus  priodon 
(Bronn).  Silurian  (Etage  E); 
Prague.  A,  Rhabdosoma, 
natural  size.  B,  Longitudinal 
section,  enlarged.  C,  Dorsal 
aspect,  enlarged.  D,  Mono- 
graptus hnhemicus  Barr.  Same 
locality.  a,  Virgula  ;  c,  Com- 
mon canal ;  th,  Thecae  ;  x, 
External  aperture  (after 
Barrande). 


Fig.  194. 

a,  c,  Climacograptus  typicalis 
Hall,  Ordovician  (Trenton 
limestone) ;  Cincinnati,  Ohio. 
a,  Vertical  section,  enlarged, 
showing  central  virgula ;  b, 
Individnal  of  the  natural  size  ; 
c,  Cross-section,  enlarged  ;  d,  e, 
Diplograptus  palmeus  Barr. 
Silurian  ;  Prague.  Rhabdo- 
soma of  the  natural  size  and 
several  times  enlarged  (after 
Barrande)  ;  /,  Diplograptus 
foliaceus  Murch,  Ordovician 
(Llandeilo  Group);  Scotland. 
natural  size  (after  Lapworth). 


Fig.  196. 

Dictyonema  cavernosum  Wiman.  Or- 
dovician ;  Gotland.  Proximal  end  of 
rhabdosome  with  adhesion  disk  (x),  large 
nourishing  individnal  (z),  and  sniall 
budding  individnal  or  gonangium  (zi). 
3/i  (after  Winian). 


latter  are  again  divided  into  two  suborders  :  AxonoUpa  Frech,  redefined  by 
Ruedemann,  without  axis  or  virgula;  and  Jxonophai-a  Frech,  limited  by 
Ruedemann,  with  an  axis.  ^ 

Order  1.      DENDROIDEA   Nicholson. 

Family.     Dendrograptidae    Roemer. 

This  family,  which  includes  all  dendroid  forms,  is  represented  during  the 
older  Paleozoic  by  the  genera  Deiidrograptus,  Dictyonema,  Desmograptus,  Gallo- 


128 


COELENTERATA— HYDROZOA 


PHYLUM  II 


gmptus  and  Ftilograptus.  Their  polyparies  are  finely  branching  and  plant-like 
in  appearance,  sometimes  furnished  with  a  strong  foot-stalk,  in  other  cases 
terminating  acutely  at  the  base.  The  original  substance  was  undoubtedly 
chitinous.  In  well-preserved  specimens  are  seen  on  one  or  occasionally  on 
both  sides  of  the  branchlets  numerous  small  cellules  or  thecae,  in  which 
evidently  the  zooids  were  seated.  These  thecae  have  been  shown  by  Wiman 
to  be  of  threefold  character,  some  of  them  having  lodged  nourishing,  others 
budding  and  others  sexual  individuals  or  gonangia.  Very  often  the  branches 
of  the   dendroid  rhabdosome  are  united  by  numerous  delicate   processes  or 


Dendrograptus  Hall.      Rhabdosome  consisting  of  a  strong  main  stem  and  a 
broad,    spreading,    shrublike,    variously  ramifying  frond.     Thecae  commonly 


Fig.  197. 
Didyonema  fläbelliforme  (Eichw.).     Upper  Cambrian;  Rensselaer  County,  N.Y.     A,  Sicula  with  very  long 
neina,  x  =Vi-    -ß»  Mature  rhabdosome  with  adhesion  stem,  x  ^/i  (after  Ruedemann). 


obscure,  but  sometimes  distinct  and  angular,  or  they  may  occur  as  round  or 
elliptic  pits  or  pustules,     Cambrian  to  Silurian. 

Ftilograptus  Hall.  Rhabdosome  with  branches  giving  ofF  branchlets 
alternately  on  opposite  sides,  the  general  habit  being  suggestive  of  Recent 
hydrozoans.     Ordovician  and  Silurian  ;  eastern  North  America. 

Didyonema  Hall  {Didyograptus  Hopkinson)  (Figs.  196,  197).  Ehabdosomes 
forming  funnel  or  fan-shaped  fronds,  composed  of  numerous  bifurcating 
branches  arising  from  an  acute  base,  and  united  at  intervals  by  fine  dissepi- 
ments.  Thecae  with  complicated  appendages,  their  branches  supporting  three 
kinds  of  individuals,  nourishing,  budding  and  sexual.  Cambrian  to  Car- 
boniferous ;  especially  abundant  in  Ordovician  of  Norway,  but  usually  com- 
pressed  into  a  basket-like  network. 

Desmograptus  Hopkin.  Differs  from  the  preceding  in  the  flexuous  char- 
acter of  the  branches,  which  coalesce  at  intervals ;  dissepiments  chiefly  in 
lower  part  of  the  frond.  Ordovician  to  Devonian ;  Europe  and  North 
America. 


CLASS  II 


HYDEOZOA— GRAPTOLITOIDEA 


129 


Order  2.      GRAPTOLOIDEA    Lapworth. 
Suborder  A.     AXONOLIPA    Frech  (emend.  Ruedemann). 
Family   1.     Dichograptidae    Lapworth. 
Uniserial  Graptolitoidea  tvith  bilateral  rhabdosome  ;  brauch  es  dichotomous  ;  thecae 


simple^  sub-cylindrical. 

Dichograptus  Salter  (Fig.   198). 


Rhabdosome  consisting  of  eight  simple 


Fia.  199. 

Tetragraptus  hryonoides  Hall. 
Ordovician ;  Point  L6vis,  Canada 
(after  Hall). 


Fig.  200 

Didymograptus  pennatulus  Hall. 
Ordovician ;  Point  L^vis,  Canada 
(after  Hall). 


Fig.  198. 

Dichograptus  octobracMatus  Hall.     Ordovician  (Quebec 
Group)  ;  Point  L^vis,  Canada  (after  Hall). 


Fio.  202. 


Didyynograp'  l'hyllograjnus  typv,n  Hall. 
t)is  murchisoni  Ordovician  (Quebec  Group); 
Point  L^vis,  Canada.  a,  Several 
polyparies  of  the  natural  size  ; 
b,  Ideal  cross-section,  enlarged 
(after  HaH). 


(Beck).  Middle 
Ordovician 
(L  1  a  n  d  e  i  1  0 
Group) ;  Wales. 


uniserial  branches  which  are  produced  by  repeated  dichotomy,  and  their  bases 
often  enveloped  in  a  central  corneous  disk.     Ordovician. 

Tetragraptus  Salter  (Fig.  199).  Rhabdosome  consisting  of  four  uniserial 
branches  which  are  produced  by  twice  repeated  dichotomous  division. 
Ordovician. 

Didymograptus  M'Coy  (Figs.  195,  J;  200;  201).  Rhabdosome  consisting  of 
two  symmetrical  branches  diverging  from  a  small  primary  cell  (sicula)  at 
various  angles.  Thecae  obliquely  directed,  having  the  form  of  flattened 
rectangular  prisms,  and  in  contact  with  one  another  throughout.     Ordovician. 

Phyllograptus   Hall    (Fig.  202).      Rhabdosome  leaf-like,  composed  of  four 

VOL.  I  K 


130  COELENTERATA  phylum  ii 

uniserial  rows  of  prismatic  thecae  coalescing  along  the  whole  length  of  their 
dorsal  margins  ;  the  entire  structure  resembling  Tetragraptus  with  the  four 
branches  grown  together,  each  two  back  to  back  and  forming  a  cross  in 
transverse  section.      Ordovician. 

Family  2.     Leptograptidae    Lapworth. 

Uniserial,  flexuous,  bilateral  rhabdosomes,  with  simple  or  Compound  lateral 
branches;  thecae  with  a  slightly  sigmoid  curvature, 
apertures  inclined,  somewhat  introverted. 

Leptograptus  Lapworth.  Rhabdosome  consist- 
ing  of  two  long,  filiform,  bilaterally  symmetrical 
branches.      Ordovician. 

Nemagraptus  Emmons  {Coenograptus  Hall)  (Fig. 

203).    Two  primary  branches  originating  from  the 

Fir..  203.  centre  of  a  triangulär  sicula,  more  or  less  flexed, 

Coenograptus  iiraciiis  Hall.   Orrio-    and  giving  off  simplc  branches  from  the  convex 

cian-    ""•■"''   ^"■"-    ''" '■■    '■'""•-  CO 

Hall). 


vician :    Point  Levis,  Ciinada    (after        •!.  '.i  i-^  ^       r\    ^       '    • 

sideatapproximately  regulär  intervals.  Ordovician 


Family  3.     Dicellograptidae  'Lapworth. 

Uniserial  or  uni-biserial  Graptoloidea.  Thecae  tubulär,  with  conspicuous 
sigmoid  ventral  curvature.  Apertures  situated  in  excavations  and  frequently  intro- 
verted and  introtorted. 

Dicellograptus  Hopk.     Rhabdosome  bilaterally  symmetrical,   consisting  of 
two  uniserial  branches  diverging  from  the  sicula  at  angles  ex- 
ceeding  180  degrees.     Ordovician. 

Dicranograptus  Hall  (Fig.  204).  Rhabdosome  Y-shaped,  com- 
posed  of  two  symmetrically  developed  branches  which  are 
coalescent  in  the  proximal  and  free  in  the  distal  portion  of 
their  length.      Ordovician. 

Suborder  B.     AXONOPHORA    Frech  (emend.  Ruedemann). 
Family  1.     Diplograptidae    Lapworth. 
Biserial  Graptolitoidea  with  rectilinear  rhabdosomes.  pjo  204. 

Climacograptus  Hall  (Fig.  205,  a,  c).  Rhabdosome  bilaterally  ramZT^Tl^i. 
symmetrical.  Thecae  tubulär,  ventral  walls  sigmoidally  curved,  ^Hudson  mip^v 
apertural  margin  horizontal,  situated  within  a  well-defined  ex-  New  York  (after 
cavation.     Ordovician  and  Silurian. 

Diplograptus  M'Coy  (Figs.  205,  d-f ;  206).  Rhabdosome  bilaterally  sym- 
metrical, rectangular,  concavo-convex  or  tabular  in  section.  Thecae  mostly 
sub-prismatic,  ventral  walls  inclined  and  straight.  Subgenera  :  Orthograptus 
and  Glyptograptus  Lapworth ;  Mesograptus  Elles  and  Wood ;  Petalograptus 
Suess  ;  Cephalograptus  Hopkinson.     Ordovician  and  Silurian. 

Family  2.     Glossograptidae    Lapworth. 

Biserial  Graptoloidea  with  straight  rhabdosomes,  fest  attenuated,  with  framework 
of  strengthening  ßbres.  Thecae  of  Diplograptid  type,  provided  with  spurs  and  other 
processes  which  often  form  an  external  lacework. 

Glossograptus  Emmons   (Figs.    207,    208).     Rhabdosome   having   lingulate 


CLAss  n  HYDROZOA— GRAPTOLITOIDEA  131 

outline  and  rounded  extremities,  ornamented  with  two  rows  of  isolated  spurs ; 


Fig.  205. 

a,  c,  Cliiruicograptus  typicalis  Hall.  Ordovician  (Tren- 
ton  limestone)  ;  Cincinnati,  Ohio  ;  a,  Vertical  section, 
showing  common  axis  in  the  centro,  enlarged  ;  5,  Poly- 
paiy  of  the  natural  size ;  c,  Cross-section,  enlarged. 
d,  e,  Di'plo(}raptus  jmlmeus  Barr.  Silurian  ;  Prague  ;  d, 
Polypary  of  the  natural  size ;  e,  Polypary  enlarged. 
/,  Diplograftus  foliaceus  Murch.  Silurian  (Llandeilo 
Group) ;  Scotland.     Natural  size. 


Fio.  206. 

Diplograptus  foliaceus  Hall.iUtica  shale  (Ordovician); 
Dolgeville,  New  York.  Synrhabdosome  showing 
central  organs  and  primary  disk  (hl)  with  funiculus 
(/),  to  which  the  rhabdosomes  (r)  are  attached  by  a 
slender  nemacaulus  (n).  Gonangia  (f/)  with  young 
siculae  (s)  are  also  present.     x  %  (after  Ruedeniann). 


Fkj.  207. 
Glofisogriiptus  (luadrimiicronatus  Hall  var.  approximatus 
Rued.     Utica  shale  (Ordovician) ;  Dolgeville,  New  York. 
Synrhabdosome.      x  Vi  (after  Ruedeinann). 


Fio.  20S. 

Glossograptus  quadrimucronatus  (Hall) 
var.  apjyroximatus  Rued.  Utica  shale 
(Ordovician)  ;  Dolgeville,  New  York. 
Young  synrhabdosome  showing  central 
disk  and  siculae.    x  »/i  (after  Ruedeniann). 


each  theca  with  two  long  spines.     Ordovician.     lletiograptus  Hall ;  Lasiograptus 
Lapworth.     Ordovician. 


132 


COELENTERATA 


PHYLUM  II 


Family  3.     Retiolitidae    Lapworth. 

Biserial  Graptolitoidea  with  straight  rhahdosomes,  the  latter  characterised  hy  a 
neiwork  of  delicate  chitinous  tracery  (reticula)  which  forms  the  outward  covering  of 
the  walls  of  the  thecae. 

RetioUtes  Barr.  (Fig.  209).  Rhabdosome  with  periderm  attenuated  and 
supported  on  a  meshwork  of  fibres.    Thecae  arranged  biserially,  their  apertures 

opening  outward.  Two  virgulae  attached  to 
opposite  sides,  in  the  median  plane.  Ordovician 
and  Silurian.  Subgenera :  Gladiograptus  Hop- 
kinson  and  Lapworth  ;  Gothograptus  Frech. 

Family  4.     Dimorphograptidae  Lapworth. 

Uni-biserial  Graptolitoidea,  in  which  the  proximal 
portion  is  uniserial,  hearing  thecae  of  the  general 
Monograptus  type ;  the  distal  portion  is  biserial  with 
thecae  of  the  Diplograptid  type. 

Dimorphograptus  Lapworth.     Silurian. 

Family  5.     Monograptidae    Lapworth. 

Uniserial  Graptolitoidea,  with  simple  or  Compound, 
straight  or  convex  rhabdosome  and  thecae  of  varied 
form. 

^^^-  20^-  Monograptus    Geinitz    {Monoprion    Barrande ; 

RetioiitesgeinUzianusB.vv.  mun^n^   Pomatograptus   and    Pristiograptus   Jaekel)    (Figs. 


193,  210).  Rhabdosomes  with  only  a  single 
row  of  thecae,  which  are  in  contact,  usually 
overlapping,  their  apertures  entire  or  contracted, 
often   directed  downward.      Form   of    the  rhab- 


A,  Specimen  from  siliceous 
Feuguerolles,  Calvados  ;  natural  size 

B,  C,  Polyparies  from  Motala,  Sweden. 
B,  Cross-section.  C,  Lower  end,  en- 
larged ;  calcareous  matter  dissolved 
out  by  acid.  v,  Zigzag-shaped  virgula  ; 
■y',  Rod-like  virgula ;  th,  Conjoined 
walls  of  hydrothecae ;   s',   Crossbars 

connecting  the  virgulae ;  o,  Apertures    dosome    may  be    Straight,  curved   or   somctimes 

spirally  coiled.     Silurian  and  Devonian. 

Bastrites  Barr.  (Fig.  211).  Rhabdosome  simple,  spirally  coiled;  common 
canal  very  narrow ;  distal  parts  of  thecae  more  or  less  linear  and  widely 
separated  from  one  another.  Silurian.  The  zonal  distribution  of  species  in 
Thuringia  and  Saxony  has  been  worked  out  in  detail  by  Eisel. 

Cyrtograptus  Carruthers.     Variously  branching  Monograptidae.     Silurian. 


Range  and  Distribution  of  Graptolites. 

Graptolites  are  excellent  index  fossils  of  the  older  Paleozoic  rocks,  owing 
to  their  limited  vertical  ränge,  and  wide  geographical  distribution.  The 
simpler  forms,  such  as  are  derived  by  a  succession  of  budding  from  a  primary 
sicula  (Axonolipa),  are  especially  characteristic  of  the  uppermost  Cambrian 
and  lower  half  of  the  Ordovician  rocks.  The  group  as  a  whole  becomes  extinct 
at  the  close  of  the  Silurian,  except  for  a  few  stragglers  in  the  Devonian  and 
Carboniferous.  The  occurrence  of  these  organisms  in  rocks  of  the  same  age 
in  all  parts  of  the  world  is  explained  by  the  fact  that  while  some  forms  were 


w 


SUBCLASS  II 


HYDROZOA— ACALEPHAE 


133 


probably  attached  to  seaweeds,  as  often  in  modern  hydroids,  others  were  free- 
floating  or  planktonic  creatnres. 

Remains  of  Graptolites  are  profusely  distributed  in  the  siliceous  schists 
and  alum  slates  of  the  Fichtelgebirge,  Thuringia,  Saxony  and  Bohemia. 
They  are  plentiful  also  in  the  Harz,  in  Poland,  Silesia,  the  Baltic  Provinces 
and  the  Ural  district ;  and  again  in  Scandinavia,  Cumberland,  Wales,  the 
north  of  England,  Scotland  and  Ireland,  as  well  as  in  Normandy,  Brittany, 
Spain,   Portugal,  Sardinia  and  Carinthia.      In  America  they  are  found  ex- 

a    '      h  c  quisitely     preserved      in      Newfoundland, 

Canada,  New  York,  Virginia,  Alabama, 
Ohio,  Wisconsin,  Iowa  and  Arkansas.    They 


Fig.  210. 

a,  Monograptus  nilssoni  Barr.  Silurian  (Alum 
Schists) ;  Gräfenwerth,  near  Schleitz,  Germany; 
h,  Monograptus  colonus  Barr.  Silurian ;  Eliots- 
tieid, Scotland,  showing  sicula  (after  Lap- 
worth) ;  c,  Monograptus  turriculatus  Barr.  Sil- 
urian ;  Prague  (after  Barrande).  All  figures 
natural  size. 


Fig.  211. 

Rastrites  Knnaei  Barr.    Silurian  ;  Zekko- 
witz,  near  Prague  (after  Barrande). 


are  known  also  in  South  America  (Bolivia),  and  Australia,  and  are  not  un- 
common  in  the  drift  which  Covers  the  plains  of  Northern  Germany. 

According  to  Lapworth,  Graptolites  are  distributed  vertically  throughout 
six  difFerent  horizons ;  'the  first  of  these  coincides  with  the  Upper  Cambrian, 
the  three  foUowing  with  the  Ordovician,  and  the  two  uppermost  with  the 
Silurian.  The  Monoprionidae  are  especially  characteristic  of  the  two  Silurian 
horizons. 

[The  discussion  of  tlie  group  Graptolitoidea  in  the  present  work  has  been  revised  by  Dr. 
Rudolf  Riiedemann,  of  the  New  York  State  Geological  Survey,  at  Albany,  New  York. — 
Editor.  1 


Subclass  2.     ACALEPHAE    Cuvier.     Scyphomedusae.^ 

{Discophora  Huxley). 

Free-swimming,  discoidal  or  bell-shaped  Medusae,  with  downwardly  direded  mouth, 
with  gastro-vascular  pouches  and  numerous  radial  canalSj  and  having,  as  a  rule,  the 
margin  of  the  umhrella  lobed.     Cambrian  to  Eecent. 

The  Acalephs  or  Lobed  Jelly-fishes,  though  frequently  of  considerable 
size,  are  entirely  without  hard  parts,  and  therefore  are  unfitted  for  preservation 

^  Literature  :  Huxley,  T.,  Memoir  on  the  Anatomy  and  Affinities  of  the  Medusae.  Phil.  Trans,, 
1849. — K7ier,  R.,  Ueber  eine  Meduse  in  Feuerstein.  Sitzungsber.  Akad.  Wiss.  Wien,  1865,  vol.  lii. — 
Haeckel,  E.,  Ueber  fossile  Medusen.  Zeitschr.  für  Wissenschaft.  Zool.,  1865  and  1870,  vols.  xv.,  xvii. 
Neues  Jahrb.  für  Mineral.,  1866.  Jenaische  Zeitschr.,  1874,  vol.  viii.  System  der  Medusen,  i.  and 
ii.,  Jena,  \^^0-^\.—Nathorst,  A.  G.,  Om  Aftryck  af  Medusor,  etc.      K.  Svenska  Vetensk.  Akad. 


134 


COELENTERATA 


PHYLUM  II 


in  the  fossil  state.  Nevertheless,  under  exceptionally  favourable  conditions, 
as,  for  instance,  in  the  Upper  Jurassic  Lithographie  Stone  of  Bavaria,  and  in 
the  Middle  Cambrian  shales  of  British  Columbia,  impressions  of  these  delicate 
organisms  are  sometimes  preserved,  which  admit  of  precise  determination. 

The  best  preserved  and  at  the  same  time  the  most  abundant  species  is 
Rhizostomites  admirandus  Haeckel,  belonging  to  the  Acraspedote  family  of 
Rhizostomidae  (Fig.  212).  Impressions  also  occur  in  flinty  concretions  of  the 
Upper  Cretaceous,  which  are  most  nearly  referable  to  the  Medusae.  Of  a 
more  questionable  nature  are  the  organisms  occurring  in  the  Cambrian 
sandstone  of    Lugnaes,   Sweden,  described    by   Thorrell  under   the  name   of 


Rhizostomites  admirandus  Haeck.     Lithographie  stone  ;  Eichstädt,  Bavaria.     1/7  natural  size. 
(Missing  parts  restored'in  outline.) 


Spatangopsis,  but  assigned  by  Nathorst  to  the  Acalephs.  In  the  same  strata 
also  are  found  those  peculiar  fucoidal  structures  known  as  Eophyton,  which  are 
commonly  supposed  to  be  of  vegetable  origin.  Nathorst  has  brought  forward 
evidence,  however,  to  show  that  these  may  really  have  been  produced  by  the 
trails  of  Jelly-fishes.  Here  also  should  be  noticed  the  forms  described  by 
Nathorst  as  Medusites,  frona  the  Lower  Cambrian  of  Sweden,  and  regarded  by 
this  author  as  casts  of  the  gastric  cavity  of  Jelly-fishes. 

In  1898  a  valuable  monograph  on  fossil  Medusae  was  contributed  by 
Walcott,  and  in  1911  our  knowledge  of  these  organisms  was  increased  in 
important  respects  by  the  same  author,  as  a  result  of  his  studies  of  remarkably 
well-preserved  specimens  from  the  Cambrian  of  British  Columbia. 


Handl.,  1881,  vol.  xix.—Ammon,  L.  v.,  Ueber  jurassische  Medusen.  Abhandl.  Bay.  Akad.  1883, 
vol.  xvii. — Brandt,  A.,  Ueber  fossile  Medusen.  Mem.  Acad.  Imp.  St-Petersb.,  1871,  7tli  ser., 
vol.  xvi. — Pohlig,  H.,  Altpermische  Medusen.  Festschrift  zum  70ten  Geburtstage  K.  Leuckarts, 
U^2.- -Walcott,  ö.  D.,  Fossil  Medusae.  U.  S.  Geol.  Surv.  Monogr.,  xxx.,  1898.— /c^em,  Middle 
Cambrian  Holothurians  and  Medusae.  Smithson.  Mise.  Coli.,  1911,  vol.  lix.  No.  3. — Mayer, 
A.  0\,  The  Medusae  of  the  World,  i.-iii.     Carnegie  Inst.  Wash,,  Pub.  No.  119,  1911. 


Phylum  III.    VERMES.    Worms.' 


Bilaterally  symmetrical  animals  with  unsegmented  or  uniformly  segmented,  and 
usually  elongated  bodies  having  a  distinct  body  cavity.  Segmented  lateral  appendages 
wanting.  A  dermal  muscular  sysj^em  and  paired  excretory 
canals  (water-vascular  System)  present. 

Of  all  the  larger  divisions  of  the  animal  kingdom,  none 
is  so  poorly  adapted  for  preservation  in  the  fossil  State  as 
the  Worms,  whose  bodies  are  as  a  rule  entirely  destitute 
of  hard  parts. 

All  Worms  are  bilaterally  symmetrical,  and  dorsal  and 
ventral  surfaces  are  clearlj^  differentiated.  The  unsegmented 
Worms  (Vermes  proper)  have  either  fiat  or  cylindrical  bodies, 
and  are  accordingly  distinguished  as  Platyhelminthes  or 
Fiat  Worms,  and  Nemathelminthes  or  Round  Worms.  But 
with  the  exception  of  the  Cambrian  genus  Amiskwia  (Fig. 
213),  supposed  to  be  allied  to  the  Recent  Sagltta,  and  a  few 
rare  parasitic  forms  discovered  in  Carboniferous  insects,  or 
in  Tertiary  insects  enclosed  in  amber,  neither  of  these  classes 
is  represented  in  the  fossil  State. 

•  The  segmented  Worms,  or  Annelida,  are  characterised 
by  a  division  of  the  body  into  metameres,  which,  although 
primitively  alike,  do  not  always  remain  homonomous. 
They  have  a  brain,  a  circumoesophageal  ring,  a  ventral  chain 
of  ganglia,  and  a  vascular  System.     The  body  is  more  or  less  elongated,  and 

^  Literature  :  Fander,  O.  H.,  Monographie  der  fossilen  Fische  des  silurischen  Systems  des 
russisch-baltischen  Gouvernements,  1851. — Ehlers,  A'.,  Die  Borstenwürmer  (Annelida  Chaetopoda). 
Leipzic,  1864-68.  —  Idem,  Über  fossile  Würmer  aus  dem  lithographischen  Schiefer  in  Bayern. 
Palaeontogr. ,  1868,  vol.  xvii. — Olaparede,  Vi'.,  Recherches  sur  la  structure  des  Annelitles  sedentaires, 
1873. — Newherry,  J.  *S'.,  Palaeontology  of  Ohio,  vol.  ii.  part  2,  1875. — Ilinde,  G.  J..  On  Conodonts 
from  the  Chazy  and  Cinciunati  Groups  ;  and  on  Annelid  Jaws  from  the  Cambro-Silurian,  Silurian, 
and  Devonian  Formations  in  Canada,  and  from  the  Lower  Carboniferous  in  Scotland.  Quar.  Journ. 
Geol.  Soc,  1879,  vol.  xxxv. — Ulrich,  E.  0.,  Journ.  Cinciunati  Soc.  Nat.  Hist.,  1879,  vol.  i. — 
Hitide,  G.  J.,  On  Annelid  Jaws  from  the  Wenlock  and  Ludlow  Formations  of  the  West  of 
England.  Quar,  Journ.  Geol.  Soc,  1880,  vol.  xxxvi. — Etheridge,  R.,jun.,  British  Carboniferous 
Tubicolar  Annelida.  Geol.  Mag.,  1880,  vol.  vii. — Nathorst,  A.  G.,  On  the  Tracks  of  sonie 
Invertebrate  Animals  and  their  Palaeontological  Significance.  K.  Svensk.  Vetensk.  Akad.  Handl., 
1881-86,  vols.  xviii.,  xxi. — Ilinde,  G.  J.,  On  Annelid  Remains  from  tlie  Silurian  Strata  of  the  Isle  of 
Gotland.  Bihang  tili  K.  Svensk.  Vetensk.  Akad.  Handl.,  1882,  vol.  \n.~Zittel,  K.  A.,  and 
Rohon,  J.  V.,  Ueber  Conodonten.  Sitzber.  Bay.  Akad.  Wiss.,  1886,  vol.  xvi.—Clarke,  J.  M., 
Annelid  Teeth  from  the  Lower  Portion  of  the  Hamilton  Group,  New  York.  Sixth  Annual  Report, 
N.Y.  State  Geologist,  1886. — Rovereto,  G.,  Studi  monografici  sugli  Annelidi  fossili.  Palaeont.  Ital., 
1904,  vol.  X.—  Walcott,  O.  D. ,  Middle  Cambrian  Annelids.   Smithson.  Mise.  Coli. ,1911,  vol.  Ivii.  No.  5. 

135 


Fig.  213. 

AmislauiM  sayltti- 
formis  Walcott.  Mid- 
dle Carnbrian;  British 
Columbia.  Flatt«ned 
specimen,  x  ^/i  (after 
Walcott). 


136 


VEEMES 


PHYLUM  III 


sometimes  flattened,  sometimes  cylindrical.  According  as  the  internal 
Segments  correspond  exactly  with  the  external,  or  as  each  internal  segment 
corresponds  to  a  definite  number  (3,  4  or  5)  of  the  external  rings,  two 
classes,  Chaetopoda  and  Hirudinea,  are  distinguished.  A  further  difference  is 
to  be  noticed  in  the  locomotive  organs,  the  Chaetopoda  having  bristle-bearing, 
unjointed  appendages  (parapodia)  on  each  ring  of  the  body  ;  and  the  Hirudinea 
having  a  terminal  sucker.  The  latter  group  includes  only  the  Leeches,  which 
are  not  known  with  certainty  in  the  fossil  State.  Fossil  representatives  of  the 
third  class,  the  Gephyrea,  Annelids  with  the  body  devoid  of  any  appearance 
of  segmentation  in  the  adult  condition,  are  known ;  but  of  the  fourth  and  last 
class  Archiannelida,  the  most  primitive  of  all  living  Annelids,  no  fossil  remains 
have  been  found. 

Class  1.  CHAETOPODA.    (Earthworms,  Annelids,  etc.) 

It  is  only  with  the  subclass  of  mari>ne  worms  (Polychaeta)  that  the 
paleontologist  is  concerned  since  the  earthworms  and  their  allies  (Oligochaeta) 
are  wholly  unknown  as  fossils.  The  marine  Chaetopoda  are  divisible  into 
three  Orders,  the  Miskoa,  the  Tubicola  or  Sedentary  Worms,  and  the  Nereid 
or  Errant  Annelids. 

Order  1.     MISKOA   Walcott. 

Polychaeta  with  similar  segments  and  parapodia  throughout  the  length  of  the  hody  ; 
retradile  prohoscis ;  straight  enteric  canal.  Body  not  distinctly  speciaUsed  into 
sections. 

This  Order  is  founded  upon  a  remarkable  series  of  Annelids  discovered  by 


HP^r'^rlJ  , 

Wl 

ffjgKKl 

|BfcL,     V-    i^k 

1^^ 

^1 

Fig.  214. 

Wiwaxia  corrvgata  Walcott.  Middle 
Cambrian  ;  British  Columbia.  Crushed 
specimen  showing  displaceü  spines  and 
scales,  X  i/i  (after  Walcott). 


i'Kis.  zia  aiid  216. 

Cambrian  Polychaeta  from  British  Columbia  (after 
Walcott).  Canadia  spinosa  and  Aysheaia  ■pedunculata 
Walcott,  both  x  ^/a- 


Walcott  in  the  Middle  Cambrian  of  British  Columbia  and  described  by  him  in 
1911.  The  Order  is  represented  by  four  families,  namely  Miskoidae  and 
Aysheaidae,  with  the  genera  Mislwia  and  Aysheaia  respectively ;  Canadidae 
including  Canadia  and  Selkirkia ;  and  the  Wiwaxidae  with  the  three  genera 


LASS  I  CHAETOPODA  137 


'iwaxia,  Pollingeria  and  JVorthenella.     Typical  examples  of  these  Annelids  are 
shown  in  Figs.   214-16.     Frotoscolex  and  Eotrophonia  Ulrich,  from  the  Eden 


Fig.  217. 
Gephyrean  Annelid,  I'ikaia  gracücns  Walcott.     Middlc  Cambrian  ;  British  Columbia,  x  2/j  (from  Walcott). 

shale  of  the  Ohio   Valley,  are  probably  Ordovician  representatives  of   this 
Order. 

Order  2.     TUBICOLA.     (Sedentaria.) 

Pohjchaetous  Annelids  with  indistindly  separated  head,  and  short,  usually  non- 
protrusible  prohoscis,  witJiout  jaws.  Parapodia  short,  and  never  used  for  swirnming . 
Inhabiting  more  or  less  firm  tuhes,  which  they  construd,  and  subsisting  upon  vegetable 
matter. 

The  Tubicolous  Annelids  invest  themselves  with  a  protective  tube  of  more 
or  less  irregulär  form,  to  which  they  are  not  organically  attached,  and  within 
which  they  can  move  freely.  Sometimes  the  tubes  are  free,  but  more  com- 
monly  they  are  attached  to  foreign  objects,  either  by  the  apex  or  by  one  side, 
and  may  occur  either  singly  or  in  Clusters.  The  tubes  frequently  consist  of 
concentric  layers  of  lime-carbonate,  with  vesicular  cavities  between  the 
lamellae,  or  the  latter  may  be  traversed  by  fine  tubuli.  In  other  cases  the 
tubes  are  composed  of  agglutinated  grains  of  sand  and  other  foreign  particles ; 
or  they  may  be  membranaceous  or  leathery.  The  materials  for  constructing 
the  tubes  are  procured  by  the  tentacles  or  branchial  filaments  of  the  head, 
and  are  cemented  together  by  a  glutinous  secretion  from  large  glands.  Fossil 
worm-tubes  are  by  no  means  of  infrequent  occurrence,  and  are  known  from 
the  Ordovician  onwards.  Only  a  few  of  the  more  common  examples  can  be 
mentioned  here. 

Serpula  Linn.  (Fig.  218).  ünder  this  head  are  included  the  majority  of 
fossil  Tubicolous  Annelids.  They  build  firm,  irregularly  contorted,  sometimes 
spirally  enrolled,  free  or  adherent  calcareous  tubes,  which  are  frequently 
clustered  together  in  large  numbers.  Beginning  in  the  Silurian,  they  are 
sparsely  represented  in  the  Paleozoic  era ;  but  from  the  Jura  onward,  nunier- 
ous  forms  occur,  the  usual  condition  being  attached  upon  other  fossils. 
Notably  in  the  Lower  Cretaceous  their  gregarious  masses  form  beds  of  con- 
siderable  thickness  (Serpulitenkalk  of  Brunswick,  and  Serpulitensand  of 
Banne witz,  near  Dresden).  .  S.  spirulaea  Lam.  (Fig.  218,  H)  is  an  abundant 
and  characteristic  Eocene  species.  Eecent  Serpulas  have  a  world  -  wide 
distribution. 


138  VERMES  phylüm  iii 

Terehella   Cuv.    (Fig.    218,   I).     Cylindrical,    elongate,    more  or   less  beut 


Fi(!.  218. 

A,  Serpula  Umax  Goldf.  Middle  Jura ;  Franconia.  ß,  C,  S.  gurdialis  Schloth.  Upper  Cretaceous  :  Banne- 
witz, near  Dresden.  D,  S.  convoluta,  Goldf.  Middle  Jura;  Stuifen,  Wurtembercr.  E,  S.  socialis  Goldf.  Middle 
Jura ;  Lahr,  Baden.  F,  Same,  enlarged.  G,  S.  septevisulmta  Reich.  Upper  Cretaceous ;  Bannewitz.  H,  S. 
(Rot.ulariaJ)efr.)spirulaeaIjam.  Eocene  ;  Monte  Berici,  near  Vicenza.  I,  TerpheUalapilloides  Münster.  Upper 
Jura ;  Streitberjr,  Franconia. 


tubes,  composed  of  cemented  grains  of  sand,  fish-debris,  or  other  adventitious 

particles.     Lias  to  Eecent. 

Spirorbis  Daudin  {Microconchus  Murch.) 
(Fig.  219).  Minute,  snail-like  or  spirally 
enrolled  calcareous  tubes,  cemented  by  the 
flattened  under  side.  The  spiral  may  be 
either  dextral  or  sinistral,  and  is  usually 
ornamented  externally  with  concentric  Striae 
or  annulations,  sometimes  with  tubercles  or 
spines.  Abundant  in  the  Paleozoic  forma- 
tions  from  the  Ordovician  onward,  and  also 
at  the  present  day ;  somewhat  less  common 
in  the  Mesozoic  and  Cenozoic  eras.  Kecent 
species  usually  adherent  on  seaweeds. 


Fig.  219. 
Spirorhis    omphalodes    (Goldfuss). 


Tubes 


seated  upon  a  Brachiopod  shell  {Schiichertella 
umhraculnm).     Devonian  ;  Gerolstein,  Eifel. 

The    foUowing    genera     are 
regarded  as  Annelids,  but  their  systematic  position  is  doubtful : 


commonly 


CLASS  I 


CHAETOPODA 


139 


Serpulites  Mnrdh.  Very  long,  smooth,  compressed,  and  somewhat  bent 
calcareous  tubes,  the  layers  admixed  with  organic  substance.  Ordovician  and 
Silurian. 

CornuUtes  Schloth.  Thick-walled,  trumpet-shaped  tubes,  Serpula-like  at  the 
lower  end,  and  sometimes  attaining  a  length  of  three  or  four  inches.  Exterior 
annulated,  and  covered  with  very  -fine  longitudinal  Striae.  Some  authors 
regard  the  tubes  as  Pteropod  shells.     Ordovician  to  Devonian. 

Ortonia   Nich.     Small,  conical,   slightly   flexuous,    thick-walled   calcareous 
tubes,  cemented  by  the  whole  of  one  surface  to  some  foreign  body.     Sides  of 
the  tube  ringed  with  imbricating  annulations,  the  free  upper  surface  apparently 
cellular  in  structure.     Ordovician  to  Carboni- 
ferous. 

Conchicolites  Nich.  Conical,  slightly  bent, 
thin-walled  tubes,  growing  together  in  Clusters, 
and  attached  by  the  small  lower  ends  to 
orthoceratite  or  Brachiopod  shells.  Tubes 
made  up  of  numerous  short  rings,  each  of 
which  partially  overlaps  the  subjacent  one. 
Ordovician. 

The  peculiar  group  Myzostomidae,  which 
are  external  parasites  on  Kecent  Crinoids,  are 
thought  to  be  related  to  the  Chaetopoda. 
Graff  has  shown  that  they  also  infested  the 
column  Segments  of  Jurassic  Crinoids. 


Order  3.     ERRANTIA.     (Nereidae). 


Free  -  swimming,  predaceous  Polychaeta,  with 
well-marJced  liead.  Proboscis  capoMe  of  protrusion, 
and  armed  with  papillae  or  powerful  jaws.  Para- 
podia  7nuch  more  developed  than  in  the  Tubicola, 
heset  with  setae,  and  serving  for  locomotion. 


Undoubted  remains  of  Errant  Worms  have 
long  been  known  from  the  Lithographie  Stone 
(Upper  Jura)  of  Bavaria,  and  include  the 
trails,  calcified  jaws  and  excrements  of  num- 
erous species.  The  principal  genus  from  this 
horizon  is  Eunicites  Ehlers  {Geophilus  Germar) 
(Fig.  220),  perfect  impressions  of  which  are 
also  found  in  the  Upper  Eocene  limestone  of 
Monte  Bolca,  Italy.  Archarenicola  Horwood 
is  known  from  the  English  Rhaetic. 

Uiider  the  designation  of  Lumhricaria 
Münster   (Lumbricites  Schlotheim)  (Fig.    221) 

are  included  a  variety  of  obscure.  remains  from  the  Lithographie  Srone, 
which  may  be  best  regarded  as  the  excrements  of  Annelids.  They  occur 
as  irregularly  contorted  bands  or  strings,  sometimes  in  the  form  of  very 
long  labyrinthic  coils. 

Of  peculiar  interest  are  the  minute  detached  jaws  and  denticulated  plates 


Fig.  220. 

Eunicites  avitus  Ehlers.     Lithographie 
Stone  ;  Eichstädt,  Bavaria.   Natural  size. 


140 


VERMES 


PHYLUM  III 


described  by  Hinde  in  the  Ordovician,  Silurian,  Devonian'and  Carboniferous 
rocks  of  the  United  States,  Canada,  Great  Britain  and  Sweden  (Island  of  Got- 
land).     These  are  very  small,  black,  highly  lustrous  bodies,  extremely  variable 

in  form  (Fig.  222),  and  mainly 
composed  of  chitinous  material 
which  is  unafFected  by  acid.  They 
exhibit  a  striking  resemblance  to 
the  jaws  of  recent.  Annelids,  and 
probably  represent  a  large  number 
of  genera. 

Of  less  certain  derivation  are 
the  microscopic  teeth  first  described 
by  Pander  under  the  name  of 
"Conodonts"  (Fig.  223),  which 
occur  detached  in  the  Cambrian 
(Blue  Cläy  underlying  the  Ungulite 
Grit)  of  St.  Petersburg,  and  are 
also  very  abundant  in  beds  of 
Ordovician,  Silurian  and  Car- 
boniferous age  in  Russia,  Great 
Britain,  the  United  States  and 
Canada.     They  are  usually  translucent,  lustrous  or  corneous,  and  are  composed 


Fig.  231. 

Lumhricaria  colon  Münst.     Lithograi)hic  Stone  ;  Solen- 
hofen,  Bavaria.     Natural  size. 


-3 


Fig.  222. 

Paleozoic  Annelid-jaws.  A,  Lumbriconereites  hasalis  Hinde.  Silurian  ;  Dundas,  Ontario.  lo/j.  ß^  Oenonites 
rostratus  Hinde.  Toronto.  l5/i.  C,  Eunicites  varians  Grinnell.  Toronto,  "/i-  ^,  Arabellites  scutellatus 
Hinde.     Ordovician ;  Toronto,     lö/j. 


of  carbonate  and  phosphate  of  lime.     They  exhibit  very  great  variety  in  form. 
By  Pander  and  others  these  fossils  have  been  regarded  as  fish-teeth.     Zittel 


^ 


Fig.  223. 

Conodonts,  greatly  enlarged.    A,  B,  Paltodus  truncatus  Pander  (after  Pander).    C,  Prioniodus  elegans  Pander. 
Cambrian  ;  St.  Petersburg.     D,  Polygnathus  duUus  Hinde.     Devonian  ;  North  Evans,  NeAv  York.    20/^. 

and   Rohon,    however,   consider  that  they  are   Annelid  jaws,   but  their  true 
Position  cannot  yet  be  said  to  have  been  positively  determined. 


CLASS  II 


GEPHYREA 


141 


Fig.  224. 

Nereites  camhrensis  M'Leay.     Cambrian  ;  Llampeter,  Wales. 
Natural  size. 


Olass  2.    GEPHYREA. 

Marine   Annelida   without  parajpodia  and   typically   devoid  of  any  trace  of 
segnientation  in  the  adult  condition. 

The  Cambrian  genera  referred  to  this  class  by  Walcott  differ  in  certain 

respects  from  the  Kecent  members,  but  with  our  available  information  the 

Position    here    assigned   them 

seems   most    advisable.     Two 

f amilies,  (1)  Ottoidae,  with  the 

genera  Ottoia  and  Banffia,  and 

(2)  Pikaidae,  including  Pikaia 

(Fig.  217)  and  Oesia,  all  from 

the  Middle  Cambrian  of  British 

Columbia,  are  recognised. 

A   quantity    of    supposed 

worm-borings,    trails,   impres- 

sions  and  otherobscureremains 

have  been  described  from  the 

older     Paleozoic     formations. 

The  burrows    have   the   form 

of  straight  or  tortuous  tunnels, 

and    are    sometimes    hollow, 

but  more  commonly  have  been 

filled    up    by  solid    matrix.     Various  names    have    been    applied    to   them, 

such  as  Scolithus,  Arenicola,   Histioderma,   Planolifes,   Diplocraterion,    Spirocolex, 

Scolecoderma  etc.,  but  they  are  obviously  incapable  of  precise  determination. 

Arthrophycus  Hall,  originally  described  as  a  plant,  Daedalus  (including  Vexillum 

Roualt)    and    Taonurus    Fisher- 

^^'<i4.     '''^!^^z^st^^^is^^^^^:^       Ooster  (Spirophyton  Hall),  have 

in  recent  years  been  interpreted 
as  worm  burrows.  • 

Similarly,  the  Serpentine  or 
vermiform  impressions  known  as 
Nereites,  consisting  usually  of  a 
number  of  windings,  and  often  of 
profuse  occurrence  in  various 
Paleozoic  formations,  were  until 
quite  recently  regarded  as  worm- 
trails,  or  markings  made  by 
Fucoids.  These  also  have  re- 
ceived  .  numerous  appellations, 
such  as  Nereites  (Fig.  224),  N'e- 
mertites,  Myrianites,  Nemapodia, 
Crossopodia  (Fig.  225),  Phyllodo- 
cites,  Naites,  etc.  Nathorst,  how- 
ever,  has  brought  forward  ex- 
perimental  evidence  to  prove  that  the  majority  of  these  markings  have  been 

produced  by  the  movements  of  Crustaceans,  Annelids  and  Gastropods.     A  like 

origin  may  reasonably  be  ascribed  to  the  extraordinarily  abundant  and  variable 


FifJ.  225. 

CrossopoiUa  (Crossochorda)  scotica  M'Coy.    Ordovician 
IJagnoles,  Norniandy. 


142  VERMES  phylüm  iii 

vermiform  structures  known  as  "  Hieroglyphics,"  which  occur  in  the  Flysch, 
Carpathian  Sandstone,  and  in  the  marine  facies  of  the  Cretaceous  and  Jurassic 
formations.  The  trails  known  as  Climaäichnites  Logan/  from  the  Potsdam 
sandstone  (Oambrian)  of  New  York  and  Wisconsin,  are  of  uncertain  origin, 
but  may  be  those  of  some  large  crustacean.  Other  peculiar  markings  have 
been  interpreted  by  B.  B.  Woodward  (Proc.  Malacol.  Soc,  London,  1906,  vol. 
vii.)  as  the  feeding-tracks  of  Gastropods. 

^  These  tracks,  known  as  Ölimactichnites,  were  first  described  by  Logan  {Can.  Nat.  and  Geol., 
18Ö0,  voL.v.)  and  later  recorded  by  Hall  (N.Y.  State  Mus.  42nd  Report,  1889)  from  Port  Henry, 
Essex  county,  N.Y.,  and  by  Woodworth  (N.Y.  State  Mus.  Bull.  69,  1903)  from  the  town  of 
Mooers,  Clinton  county,  N.Y.  In  the  latter  locality  they  assume  gigantic  proportions,  being  6  inches 
Wide  and  15  or  more  feet  long,  terminating  in  an  oval  Impression  16  inches  long. 

Various  explanations  have  been  suggested  for  these  tracks.  Besides  having  been  referred  to 
trilobites,  burrowing  crustaceans,  plants,  gastropods  and  annelids,  they  have  been  compared  with 
those  of  the  horseshoe  crab,  first  by  Dawson  and  recently  again  by  Hitchcock  and  Patten.  Sir 
William  Dawson  {Gan.  Nat.  and  Geol.^  1862,  vol.  vii.),  Avho  studied  Limulus  on  the  seashore, 
pointed  out  that  when  the  animal  creeps  on  quicksand,  or  on  sand  just  covered  with  water,  it  uses 
its  ordinary  Walking  legs  and  produces  a  track  strikingly  like  that  described  as  Protichnites  from 
the  Potsdam  sandstone  ;  but  in  shallow  water  just  covering  tlie  body,  it  uses  its  abdominal  gill-plates 
and  produces  a  ladder-like  track  the  exact  counterpart  of  Ölimactichnites  except  that  in  the  track  of 
Limulus  the  lateral  and  median  lines  are  furrows  instead  of  ridges.  Patten  (Science,  1908,  vol.  viii. 
p,  382)  "  described  the  inovements  of  a  modern  Limulus  in  advancing  up  a  sandy  beach  with  the  tide, 
and  the  action  of  the  abdominal  gill-plates  making  rhythmic  ridges  in  the  sand.  He  compared 
these  with  the  tracks  of  Climactichnites,  which  he  ascribed  to  forms  related  to  the  eurypterids  rather 
than  the  trilobites.  The  tracks  showed  a  beginning  in  a  hollow  in  the  sand  and  where  continued 
on  the  specimen  to  the  further  end  there  became  fainter,  as  if  the  animal  rose  from  the  bottom. 
This  would  correspond  with  the  habit  of  the  Limulus^  which  remains  buried  on  recession  of  the  tide 
and  upon  its  first  return  crawls  and  then  swims  away.  Beside  one  track  were  seen  two  symmetric- 
ally  placed  impressions  attributed  to  the  longer  arms  of  a  Eurypteroid  form." 

In  favour  of  this  view  is  the  fact  that  Strabops  is  a  Cambrian  Eurypterid  that  woiild  appear 
competent  to  produce  such  tracks  ;  contrariwise,  however,  Woodworth  has  suggested  that  the  trail 
was  made  by  a  mollusk,  and  that  the  sedentary  Impression  is  the  end  of  the  trail  instead  of  its 
beginning.  The  direction  of  the  obliquely  transverse  marks  of  (ölimactichnites  is  always  toward 
the  oval  impressions,  and  eomparison  with  those  of  the  Limulus  tracks  (Dawson,  figs.  1-3,  and  also 
fig.  157  in  Cambridge  Nat.  Hist.  vol.  iv.)  would  indicate  that  tliö  animal,  if  an  Eurypterid,  moved 
toward  the  sedentary  Impression  and  not  away  from  it.  The  most  recent  discussion  of  the  nature 
of  these  and  other  problematical  markings  is  to  be  found  in  a  paper  by  Walcott  {Smithson,  Mise. 
Coli.,  1912,  vol.  Ivii.,  no.  9),  where  it  is  suggested  that  the  Climactichnites  trails  may  have  been 
formed  by  a  largfe  segmented  Annelid  like  Pollingeria.  Specimens  of  the  latter  are  known  from 
the  Cambrian  which  have  a  length  of  13  cm.  and  width  of  7  cm. 


Phylum  IV.    ECHINODERMATA 

The  Echinoderms  are  animals  with  primarily  a  radial  (usually  pentamerous) 
and  secondarily  more  or  less  bilateral  symmetry,  which  were  formerly  included 
with  the  Coelenterates  under  the  general  category  of  Radiata ;  but  were 
recognised  by  Leuckart  as  the  representatives  of  a  distinct  animal  type. 
Recently  it  has  been  suggested  by  two  authors,  working  independently,  one 
from  a  study  of  comparative  embryology  (Patten),  and  the  other  from 
evidence  furnished  by  the  adult  anatomy  (A.  H.  Clark),  that  the  Echinoderms 
are  derived  from  acraniate  crustacean  ancestors,  through  the  Cirripedia. 

Echinoderms  possess  a  well-developed,  usually  pentamerous  dermal 
skeleton,  which  is  composed  of  calcareous  plates,  or  of  minute,  isolated, 
calcareous  bodies  embedded  in  the  integument,  and  sometimes  also  in  the 
walls  of  many  of  the  internal  organs.  The  exoskeleton  may  be  immovable, 
or  more  or  less  movable,  but  is  very  frequently  provided  with  movable 
appendages  (spines,  pedicellariae,  etc.).  The  arrangement  of  both  the 
skeletal  parts  and  the  principal  organs  is  so  generally  pentamerous,  that 
five  may  be  regarded  as  the  fundamental  numeral  pervading  the  phylum  of 
Echinoderms. 

Apart  from  this  constitutional  difFerence,  Echinoderms  are  distinguished 
from  Coelenterates  by  the  presence  of  a  true  digestive  canal,  a  distinct 
body-cavity,  a  vascular  System,  and  a  water-vascular  apparatus ;  by  a  more 
perfectly  developed  nervous  System ;  and,  except  in  certain  Starfishes,  by  an 
exclusively  sexual  mode  of  reproduction. 

The  skeleton  of  Echinoderms  is  primarily  composed  of  a  series  of  plates 
which  are  situated  in  the  integument,  and  are  covered  with  living  dermal 
tissue  during  life  of  the  individual.  Although  lying  near  the  surface,  the 
plates  are  strictly  internal  in  position,  and  are  capable  of  growth  or  resorption 
throughout  life.  Besides  skeletal  plates,  other  hard  parts  may  occur,  such  as 
spines,  pedicellariae,  the  jaws  or  so-called  "  Aristotle's  lantern  "  of  Echini,  and 
spicules  of  the  kind  found  in  the  tube-feet  and  some  of  the  internal  organs. 
Certain  Crinoids  also  show  a  series  of  calcified  convolutions  supporting  the 
digestive  tube.  The  calcification  of  the  internal  organs  is  sometimes  sufficient 
to  form  solid  skeletal  parts.  The  plates  and  other  skeletal  parts  of  Echino- 
derms are  composed  of  open  cribriform  tissue  (Figs.  226,  227),  which  in  the 
cleaned  test  of  Recent  specimens  is  highly  porous.  During  fossilisation  the 
interstices  are  commonly  infiltrated  with  lime  carbonate,  so  that  the  whole 
striicture  is  transformed  into  calcite,  exhibiting  unmistakable  rhombohedral 
cleavage.     Each  plate,   Joint  and   spine  of  a   sea-urchin,   star-fish   or  crinoid 

143 


144 


ECHINODERMATA 


PHYLUM  IV 


behaves  mineralogically  and  optically  like  a  single  calcite  crystal.  The  plates 
forming  the  main  skeleton  of  an  Echinoderm  may  be  few  or  numerous,  and 
may  be  polygonal  with  vertical  sides  forming  a  solid  skeleton,  or  they  may 
be  rounded,  scale-like  or  imbricating,  forming  a  more  or  less  flexible  test ;  or 
again  they  may  be  reduced  to  minute,  dissociated  bodies  embedded  in  the 
integument  and  forming  a  partial  dermal  skeleton,  as  in  certain  Holothurians. 
All  the  Echinoderms  are  marine,  and  only  a  very  few  of  them  occur  in 
even  very  slightly  freshened  water.     In    the  sy^stem  proposed  by  Haeckel 


Fi(i.  226. 

a,  Magnifled  cross-section  of  an 
Echinoid  spine  ;  Fiji  Islands,  b,  Mag- 
nilied  section  of  coronal  plate  of  a 
Recent  Sea  -  urchin  (Sj)haerechinus)  ; 
plane  of  section  parallel  to  surface. 


Fig.  227. 
Pentacrinus  siCbteres  Goldf.  Upper  Jura ;  Reichen- 
bach, Wurtemberg.  a,  Vertical  section  of  steni-joint  in 
plane  indicated  in  c,  18/i.  h,  Transverse  section  of 
saine,  18/i.  c,  Joint-face.  d,  Series  of  columnals 
(natural  size). 


seven  classes  are  recognised,  of  which  the  first  three,  namely,  Cystidians, 
Blastoids  and  Crinoids,  are  grouped  together  as  a  distinct  subphylum  called 
Felmatozoa.  Corresponding  to  this  are  two  other  subphyla,  Ästerozoa  and 
Echinozoa,  the  former  including  the  classes  of  Asteroids  and  Ophiuroids, 
and  the  latter  comprising  the  classes  of  Echinoids  and  Holothurians. 


Subphylum  A.     Pelmatozoa  Leuckart. 

The  Pelmatozoa  are  Echinoderms,  nearly  all  of  which,  during  the  whole  or 
at  least  the  early  portion  of  their  existence,  are  fixed  by  a  jointed,  flexible 
stalk,  or  are  attached  by  the  dorsal  or  aboral  surface  of  the  body.  The  prin- 
cipal  viscera  are  enclosed  in  a  bursiform,  cup-shaped  or  spherical  test  (calysc), 
which  is  composed  of  a  System  of  calcareous  plates.  On  the  upper  surface  of 
the  test  are  placed  both  the  mouth  and  anus,  as  well  as  the  ambulacral  or 
food  grooves  conducting  to  the  mouth.  In  some  forms,  however,  the  calyx  is 
so  reduced  as  to  form  merely  a  small  horizontal  platform  upon  which  rest  the 
viscera,  usually  protected  by  a  covering  of  secondary  dermal  plates.     As  a 


lSSi  CYSTOIDEA  IHH^V  ^^^ 

ile,  jointed  flexible  arms  spring  from  the  distal  ends  of  the  ambulacral 
"^groGves  around  the  margin  of  the  calyx ;  but  sometimes,  as  in  Blastoids,  arms 
are  wanting,  the  ambulacral  areas  being  extended  down  the  sides  of  the  calyx, 
and  beset  on  both  sides  with  pinnules.  The  inferior  (dorsal,  aboral)  portion 
of  the  calyx  is  composed  of  a  single  or  double  series  of  basal  plates,  which 
rest  either  directly  upon  the  stalk,  or  upon  a  centrodorsal  representing  a 
Single  greatly  enlarged  columnal,  or  they  may  be  grouped  about  a  central 
apical  plate  or  centrale.  Sometimes  these  plates  are  so  small  as  to  be  invisible 
externally,  so  that  the  calyx  appears  to  be  composed  of  radials  only. 

The  Pelmatozoa  comprise  three  classes :  Cystoidea,  Blastoidea  and  Crinoidea. 
Of  these,  the  first  two  are  wholly  extinct,  being  confined  to  the  Paleozoic 
rocks ;  all  three  are  found  well  developed  in  the  Ordovician,  and  doubtless 
originated  in  pre-Cambrian  time  from  unknown  ancestral  forms.  The  Cystids 
are  the  oldest,  substantially  ending  with  the  Silurian,  though  feebly  repre- 
sented  in  the  Devonian  and  Carboniferous.  The  Blastoids  culminated  in  the 
Lower  Carboniferous  and  ended  in  the  Permian.  The  Crinoids  also  cul- 
minated in  the  Carboniferous,  but  continued  to  survive,  nevertheless,  and  are 
represented  in  existing  seas  by  numerous  genera  and  species,  the  dominant 
type  being  the  unstalked  forms,  or  Comatulids. 

Olass  1.    CYSTOIDEA  Leopold  von  Buch.^ 

Extinct,  pedunculate,  or  more  rarely  sfemless  Pelmatozoa,  with  calyx  composed 
of  irwre  or  less  irregularly  arranged  plates.  Food  brought  to  the  mouth  by  a  System 
of  ciliated  grooves,  either  between  the  calyx  plates,  over  them,  or  along  processes  from 
the  calyx  {arms,  brachioles,  etc.),  or  subtegminal.  Anus  usually  on  the  oral  half  of 
the  calyx.  Calyx  plates  often  perforate.  Brachial  processes  usually  imperfectly 
developed,  sometimes  absent. 

The  calyx  is  globose,  bursiform,  ovate  or  ellipsoidal  in  form,  more  rarely 
cylindrical  or  discoidal,  and  is  composed  of  quadrangular,  pentagonal,  hexa 
gonal  or  polygonal  plates,  which  are  united  by  close  suture.  The  plates 
Vary  in  number  from  thirteen  to  several  hundreds,  and  only  exceptionally 

^  Literature  :  Volhorth,  A,  von,  Ueber  die  Echinoencrinen.  Bull.  Acad.  Imp.  Sei.  St-Petersb., 
1842,  vol.  X.  —  Volhorth,  A.  von,  lieber  die  russischen  Sphaeroniten.  Verhandl.  Mineral.  Gesell. 
St,  Petersb.,  1845-46. — Buch,  L.  von,  Ueber  Cystideen.  Abhandl.  Akad.  Wiss.  Berlin,  1844 
(1845).  Translated  in  Quart.  Journ.  Geol.  Soc.  London,  1845,  vol.  ii. — Forbes,  E.,  On  the 
Cystidea  of  the  Silurian  Rocks  of  the  British  Islands.  Meni.  Geol.  Survey  Great  Brit.,  1848, 
vol.  ii.  part  2. — Müller,  J.,  Ueber  den  Bau  der  Echinodermen.  Abhandl.  Akad.  Wiss.  Berlin, 
1853.— ^«ZZ,  J.,  Palaeontology  of  New  York,  vol.  ii.,  1852,  and  vol.  iii.,  1859.— Bülings,  K,  On 
the  Cystidea  of  the  Lower  Silurian  Rocks  of  Canada  (Figures  and  Descriptions  of  Canadian  Organic 
Remains,  Decade  III.),  1858. — Hall,  J.,  Descriptions  of  some  new  Fossils  from  the  Niagara  Group. 
20th  Ann.  Rept.  N.Y.  State  Cabinet  of  Nat.  Hist.,  1S67 .—Billings,  K,  Note.s  on  the  Structure  of 
Crinoidea,  Cystidea,  and  Blastoidea.  Amer,  Journ.  Sei.  (2nd  ser.),  1869,  vol.  xlviii.,  and  1870, 
vol.  xlix. — Volborth,  A.  voti,  Ueber  Achradocystites  und  Cystoblastus.  Mem.  Acad.  Inip.  Sei.  St- 
Petersb.,  1870,  vol.  xvi. — Schmidt,  F.,  Ueber  Baltisch-Silurische  Petrefacten.  Mein.  Acad.  Inip. 
Sei.  St-Petersb.,  1874,  vol.  xxi. — Barrande,  ./.,  Systeme  Silurien  du  Centre  de  la  Boheme,  vol.  vii. 
Cystidees,  1887. — Carpeuter,  P.  H.,  On  the  Morphology  of  the  Cystidea.  Journ.  Liun.  Soc,  1891, 
vol.  xxiv. — Haeckel,  E.,  Die  Amphorideen  und  Cystoideen,  etc.  Festschr.  für  Gegenbaur,  No.  1, 
1896. — Jaekel,  0.,  Stammesgeschichte  der  Pelmatozoen,  Thecoidea  und  Cystoidea,  1899. — Jaekel, 
0.,  Über  Carpoideen.  Zeitschr.  Deutsch.  Geol.  Gesell.,  1900,  vol.  Iii. — Bather,  F.  A.,  Treatise 
on  Zoology  (Lankester),  part  3,  Echinoderma,  1900. — Schnchert,  C,  Siluric  and  Devonic  Cystidea. 
Smithson.  Mise.  Coli.,  1904,  vol.  xlvii.  part  2. — Bather,  F.  A.,  Ordovician  Cystidea  from  Burma. 
Mem.  Geol.  Surv.  India,  1906,  n.  s.  vol.  il—Kirk,  K,  Structure  and  relation.ships  of  certain 
Eleutherozoic  Pelmatozoa.     Proc.  U.S.  Nat.  Mus.,  1911,  vol.  xli.  No.  1846. 

VOL.  I  L 


146  ECHINODERMATA— PELMATOZOA  phylüm  iv 

exhibit  a  regulär  arrangement.  Sharp  demarcations  between  the  acfcinal  and 
abactinal  Systems  of  plates,  and  between  radial  and  interradial  areas,  rarely 
exist ;  the  plates  of  the  sides  of  the  calyx  pass  insensibly  into  those  of  the 
ventral  surface,  and  are  disposed  in  regulär  cycles  only  in  a  few  instances. 
The  base,  however,  is  composed  of  a  distinct  ring  of  plates,  and  is  usually 
recognisable  by  the  presence  of  an  articular  surface  for  the  attachment  of  a 
stem,  or  by  being  directly  adherent  to  some  foreign  object. 

The  mouth  is  indicated  by  a  central  or  subcentral  aperture  on  the  upper 
surface,  or  at  the  end  opposite  to  that  which  is  attached  to  the  column  or 
stem.  It  is  sometimes  covered  by  five  small  plates  corresponding  to  the 
orals  of  Crinoids,  and  from  it  radiate  from  two  to  five  simple  or  branching 
ambulacral  grooves.  The  second  opening  on  the  ventral  surface  is  situated 
eccentrically,  and  is  frequently  closed  by  a  valvulär  pyramid,  consisting  usually 
of  five  or  more  triangulär  plates  ;  or  the  covering  may  consist  of  a  variable 
number  of  smaller  pieces.  This  aperture,  which  was  regarded  by  L.  von 
Buch,  Volborth,  Forbes  and  Hall  as  a  genital  opening,  is  now  generally  con- 
ceded  to  represent  the  anus.  A  third  smaller  opening,  situated  between  the 
mouth  and  the  anus,  is  present  in  a  few  forms  only.  The  functions  of  this 
latter  orifice  are  not  well  understood,  but  it  is  commonly  regarded  as  the 
ovarian  aperture,  or  genital  pore  (Fig.  228).  Yet  another  small,  slit-like  opening, 
situated  in  the  vicinity  of  the  mouth,  was  detected  by  Barrande  in  the  genus 
Aristocystites ;  but  its  functions  are  altogether  unknown. 

The  ambulacral  grooves,  or  food-grooves,  which  are  present  in  most 
Cystideans,  are  usually  simple,  although  sometimes  distally  branching,  and 
are  frequently  roofed  over  by  alternately  arranged  covering  pieces.  In  a  few 
forms  {Caryocrinus,  Cryptocrinus,  etc.)  the  grooves  are  wholly  absent.  The 
genera  Aristocystites,  Pyrocystites  and  Calix  are  without  exposed  ambulacral 
grooves  ;  but  they  have  instead,  as  Barrande  discovered,  a  peculiar  System  of 
five  or  six  covered  passages  on  the  inner  surface  of  the  calyx  plates,  which 
converge  towards  the  mouth,  and  are  distally  more  or  less  branching  (Fig. 
229).  These  structures,  the  so-called  "  hydrophores  palmdes,"  were  homologised 
by  Barrande  with  the  hydrospires  of  Blastoids ;  but  as  Neumayr  has  pointed 
out,  they  are  probably  the  equivalent  of  subtegminal  food-grooves  in  Crinoids. 

The  calyx  or  thecal  plates  exhibit  most  remarkable  structural  peculiarities. 
As  a  rule  they  are  more  or  less  extensively  perforated  by  pores  or  fissures  ; 
although  in  some  forms  [Cryptocrinus,  Malocystites,  Ateleocystites,  etc.)  they 
appear  to  be  imperforate,  and  are  composed  of  a  homogeneous  calcareous 
layer  of  greater  or  less  thickness,  the  same  as  in  Crinoids.  But  in  Aristo- 
cystites, Calix,  Proteocystites,  Glyptosphaerites,  Echinosphaerites,  etc.,  the  plates 
are  uniformly  covered  both  externally  and  internally  with  a  very  thin, 
generally  smooth,  calcareous  membrane,  which  may  be  perforate  or  imperforate. 
The  central  layer  is  of  varia,ble  thickness,  and  is  traversed  by  numerous 
canals  (Figs.  229,  230)  which  extend  from  the  inner  to  the  outer  surface, 
sometimes  rectilinearly  {Aristocystites,  Calix,  etc.) ;  sometimes  in  slightly 
sinuous  lines ;  and  in  rare  instances  they  divide  dichotomously.  The  canals 
terminate  on  either  surface  in  small  round  apertures  or  pores,  which  are 
arranged  either  singly  or  in  pairs,  and  may  or  may  not  penetrate  the  outer 
calcareous  membrane.  The  pores  are  commonly  situated  either  on  a  tubercular 
elevation,  or  in  a  slight  superficial  depression. 

But  still  more  frequent  than  the  canals  are  the  so-called  pore-rhomhs  (Fig. 


CLASS  I 


CYSTOIDEA 


147 


231)  which  occur  indifFerently  in  types  possessing  numerous  or  but  few 
calycine  plates.  The  pores  are  arranged  so  as  to  form  lozenge-shaped  or 
rhombic  figures,  in  such  manner  that  one  half  of  each  rhomb  belongs  to  one 
plate,  and  the  other  half  to  its  contiguous  neighbour ;  while  the  line  of  suture 
between  the  plates  forms  either  the  longer  or  the  shorter  diagonal  of  the 
rhomb.  The  pores  of  opposite  sides  of  the  rhomb  are  united  by  perfectly  closed, 
straight  ducts,  which  pass  horizontally  through  the  middle  layer  and  across 
the  line  of  suture  between  the  two  plates,  thus  producing  a  transversely 
striated  appearance.  Occasionally  the  connecting  tubes  appear  on  the  outer 
surface  as  elevated  striate  rhombs ;  but  as  a  rule  they  are  concealed  by  the 
above-mentioned  covering  layer,  and  are  only  visible  in  weathered  or  abraded 
specimens.     The  pores  of  the  rhombs  also  communicate  with   short  canals 


Fig.  229 


Aristocystites.  Canals 
perforating  the  median 
layer  of  plate. 


Fig.  230. 

a,  Aristocystites.  Inner  snrfaceof  two 

calyx  plates  showing  simple  pores ; 

b,  Glyptosphaerites.     Outer  surface  of 

calyx  plate  showing  double  i)ores. 


Fig.  228. 

Glyptosphaerites  leuchtenhergi  Volborth. 
Calyx  showing  ambulacral  grooves,  plated 
mouth-opening,  large  laterally  situated  anus, 
and  small  ovarian  aperture  between  mouth 
and  anus. 


Fig.  231. 
Pore-rhombs  of  (a)  Echinosplmerites,  and  (h)  Caryocrinus, 
enlarged.     The  left  half  of  Fig.  a  is  abraded,  so  that  the 
connecting-tubes  appear  as  open  grooves. 


passing  vertically  through  the  plates,  the  ends  of  which  are  either  covered 
over  by  the  outer  calcareous  layer,  or  appear  on  both  surfaces  as  fine  indepen- 
dent  pores.  A  pair  of  oppositely  situated  pores  of  the  latter  description 
may  sometimes  receive  as  many  as  two  or  three  fine  canals,  while  in  other 
genera  they  are  entirely  wanting. 

The  pore-rhombs  are  sometimes  present  upon  nearly  all  plates  of  the  calyx, 
but  in  other  cases  they  are  only  developed  on  a  certain  number  or  on  all  of 
the  plates  forming  the  side-walls  of  the  calyx,  being  absent  from  its  upper 
surface.  In  still  other  instances  {Pleurocijstites,  Callocystites,  Fig.  232),  the 
pore-rhombs  are  greatly  reduced  in  number,  and  occur  in  the  form  known  as 
pectinated  rhombs  or  pedino-rhombs.  The  component  halves  of  the  latter 
stand  on  contiguous  plates  the  same  as  the  ordinary  pore-rhombs,  but  are 
always  separated  externally  by  an  interval ;  frequently  the  two  parts  are  of 
different  form  or  size,  and  sometimes  one  of  them  may  become  obsolescent. 

As  regards  the  functions  of  these  canals  and  pores  (the  "  hydrospires  "  of 


148 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


Fig.  232. 
Callocystitesjeweiti  Hall.     Silurian  (Niagara  Group);  Lockport,  New 
York.     A,  Calyx  from  one  side  (natural  size).     B,  Ambulacral  grooves 
and  tliree  pectinated  rliombs  (r/t),  enlarged ;  o,  Mouth ;  an,  Anus ;  g, 
Genital  pore  (after  Hall). 


Billings),  the  anatomy  of  existing  Crinoids  furnishes  us  with  no  positive  con- 
clusions.  They  have  been  compared  with  the  pores  which  are  present  in  the 
tegmen  of  the  latter,  and  the  rather  plausible  Suggestion  has  been  ofFered  that 
they  served  to  admit  water  into  the  body-cavity,  and  thus  performed 
respiratory  functions.  At  all  events,  they  could  not  have  served  for  the  pro- 
A  ß  trusion  of  tube-feet,  since 

they  are  frequently  covered 
over  by  an  outer  calcareous 
membrane,  which  efFectu- 
ally  shuts  ofF  communica- 
tion  with  the  exterior. 

The  arms  or  brachioles 
in  the  Cystideans  are  as 
a  rule  feebly  developed, 
and  are  sometimes  either 
entirely  wanting,  or  re- 
duced  in  number  (2,  3,  6, 
9-13).  The  pentamerous 
symmetry,  so  generally 
characteristic  of  Echino- 
derms,  pervades  neither  the  arrangement  of  the  calyx  plates  nor  the  number 
and  disposition  of  the  arms.  The  latter  are  invariably  simple,  are  either 
uniserial  or  biserial,  and  exhibit  a  ventral  groove  protected  by  covering  plates. 
In  some  genera  the  arms  attain  considerable  thickness,  but  in  others  they 
are  very  diminutive,  and  seem  to  have  closer  affinities  with  pinnules  than 
with  the  arms  of  Crinoids.  In  the  Callocystidae  and  Agelacrinidae,  as  well  as  in 
the  Canadian  genera,  Amygdalocystites  and  Malocystites,  the  arms  are  either 
recumbent  with  their  dorsal  side  facing  the  calyx,  or  they  are  prostrate  and 
incorporated  into  the  calyx.  The  ventral  side,  in  these  cases,  is  directed  out- 
wardly,  and  the  ambulacral  furrow  is  bordered  on  either  side  by  a  row  of 
alternating,  jointed  pinnules,  which  are 
attached  by  small  articular  facets  running 
parallel  with  the  groove. 

The  stem,  as  a  rule,  is  greatly  abbrevi- 
ated,  and  is  frequently  obsolete.  Some- 
times the  calyx  is  attached  by  the  entire 
lower  surface  (Agelacrinus) ;  or  in  other 
cases  by  means  of  a  tubulär  process 
(Echinosphaerites).  Only  in  rare  instances 
does  the  stem  appear  to  have  served  for 
attachment,  since  it  generally  tapers  dis- 
tally  to  a  point,  and  is  invariably  destitute 

of  cirri.  The  stem  sometimes  resembles  that  of  the  Crinoids,  in  being  composed 
of  a  number  of  short,  prismatic  or  cylindrical  joints ;  these  are  pierced  by  a 
wide  canal,  and  are  either  united  by  horizontal,  striated,  articular  surfaces,  or 
they  overstride  one  another  like  the  draw-tubes  of  a  spy-glass.  In  other  cases 
the  Upper  part,  and  occasionally,  indeed,  the  entire  stem,  is  composed  of  vertical 
rows  of  alternating  plates.  These  plates,  as  a  rule  (Dendrocystites),  enclose 
a  large  central  space,  which  may  be  regarded  as  a  Prolongation  of  the  body- 
cavity. 


Fig.  233. 

a,  Aristocystites.  Subtegminal  ambulacral 
grooves  ;  b,  Same  of  Pyrocystites.  Enlarged  (after 
Barrande). 


CLASSi  CYSTOIDEA  149 

The  Cystideans  coiistitute  the  oldest  and  least  specialised  group  of  the 
Pelmatozoa.  Appearing  first  in  the  Cambrian,  they  develop  a  great  variety  of 
forms  in  the  Ordovician  and  Silurian,  but  become  extinct  before  the  close  of 
the  Carboniferous.  While  their  own  ancestry  is  obscure,  it  is  highly  probable 
that  from  them  have  descended  both  the  Crinoids  and  Blastoids.  If,  on  the 
one  band,  the  families  of  Aristocystidae,  Sphaeronitidae  and  Echinosphaeritidae 
differ  radically  from  Crinoids  in  respect  to  their  numerously  and  irregularly 
plated  calyx,  or  as  regards  the  feeble  development  or  even  total  absence  of 
their  arms ;  nevertheless,  the  Cryptocrinidae  and  the  imperfectly  preserved 
Cambrian  genus,  Lichenoides,  evince  a  striking  similarity,  especially  as  concerns 
the  more  or  less  regulär  arrangement  of  the  calyx  plates,  and  a  certain 
approach  to  radiation.  On  the  other  band,  forms  like  Porocrinus  and  Cleiocrinus, 
along  with  strong  pentamerous  symmetry  and  regulär  arrangement  of  plates 
which  seem  to  ally  them  with  the  Crinoids,  have  also,  in  the  presence  of 
pectino-rhombs  and  calycine  pores,  characters  by  which  they  might  with  equal 
propriety  be  assigned  to  the  Cystids. 

If  we  can  explain  the  derivation  of  Crinoids  from  Cystideans  on  the 
supposition  that  the  calyx  plates  of  the  latter  gradually  took  on  a  more 
definite  arrangement,  while  the  loss  of  pores  and  pore-rhombs  was  counter- 
balanced  by  a  stronger  development  of  the  arms  and  the  stem ;  so,  too,  it  is 
possible  to  derive  Blastoids  from  the  same  source.  Although  hydrospires 
are  clearly  wanting  in  the  Cystids,  nevertheless,  other  characters,  such  as  the 
recumbent  attitude  of  the  arms  upon  the  sides  of  the  calyx,  or  their  Insertion 
in  grooves  on  the  ventral  surface,  predicate  an  intimate  relationship  with 
the  Blastoids.  Probably  the  most  notable  similarities  are  presented  by  the 
peculiarly  modified  families,  Callocystidae  and  Agelacrinidae.  Various  attempts 
have  been  made  to  affirm  a  connection  between  Agelacrinus  and  the  Asteroidea, 
and  between  Mesites  and  certain  of  the  Silurian  Echinoidea  (Echinocystites) ; 
but  such  hypotheses  are  scarcely  warranted,  since  they  proceed  from  an  over- 
valuation  of  purely  external  resemblances,  which  in  nowise  prove  genetic 
relationship. 

The  Cystids  were  first  recognised  as  a  distinct  division  of  Echinoderms  by 
Leopold  von  Buch  in  1844,  but  their  more  detailed  Classification  long  remained 
in  an  unsatisfactory  condition,  and  is  still  involved  in  considerable  difficulty. 
This  is  largely  owing  to  the  comparative  scarcity  of  material  and  its 
frequently  imperfect  preservation,  affording  insufficient  knowledge  of  the 
exact  structure  in  many  forms.  The  Classification  of  Johannes  Müller  was 
based  primarily  upon  the  structure  of  the  calyx  plates,  according  to  which 
two  main  groups  were  recognised,  BJiombifera  and  Diploporita.  To  these 
Roemer  afterwards  added  a  third,  Aporita,  and  other  divisions  were  made  by 
Barrande,  Neumayr  and  Steinmann.  In  later  years  the  Cystids  have  been 
treated  extensively  by  Haeckel,  Bather,  and  Jaekel,  who  have  proposed 
classifications  based  upon  phylogenetic  principles.  While  in  some  general 
features  these  are  in  substantial  agreement  they  differ  considerably  in 
details.  The  arrangement  adopted  by  Bather,  with  some  of  the  modifica- 
tions  introduced  in  the  later  editions  of  Zittel's  Grundzüge,  is  in  the  main 
here  followed. 


150 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


Order  1.     AMPHORIDBA    Haeckel  {pars). 
No  radial  symmetry  in  food  grooves  or  calyx  plates. 

Family  1.     Aristocystidae    Neumayr. 

Calyx  composed  of  numerous  plates  without  regulär  arrangement.     No  extension 
a  of  food-grooves  or  brachial  processes.     Stern  undeveloped, 

or  very  short.     Cambrian  to  Silurian. 

Pilocystites,  Lapillocystites  and  Acanthocystites  Bar- 
rande.  Cambrian ;  Bohemia.   These  are  obscure  genera. 
Aristocystites  Barr.  (Fig.   234).     Calyx  bursiform 
or  ovate ;  ventral  surface  with  four  apertures ;  stem- 
less.     Ordovician ;  Bohemia. 

Deutocystites  Barr.  Ven- 
tral surface  with  three  aper- 
tures. Calix  Eouault  (Cra- 
terina  Barr.).  Conical,  trun- 
cate.  Baculocysfites  Barr. 
Ordovician ;  Bohemia. 

Megacystites  Hall  (Holocystis 
S.  A.  Miller).  Elongate, 
cylindrical  or  sub-cylindrical ; 
short  -  stemmed  or  stemless, 
with  subcentral  mouth.  Silur- 
ian ;  North  America,  Gotland. 
Said  to  be  a  sponge. 


Aristocystites   boJiemicus]  Barr.      Ordovician   (Dd'^) ;    Zahorzan 
Bohemia.     a,  Side  view  ;  b,  Summit  aspect  (after  Bariande). 


?  Lodanella  Kayser.     Devonian  ;  Germany. 


Family  2.     Anoraalocystidae  Meek. 


Calyx  oval,  more  or  less  compressed,  with  dissimilarly  plated  hroad  sides. 
either  imperforate  or  with  simple  pores  ;  pore-rhomhs  ahsent. 
Food-grooves  extended  in  one  or  more  processes.     Stem  short, 
tapering,  of  polymeric  columnals.     Cambrian  to  Silurian. 

Trochocystites  Barr.  (Trigonocystis  Haeckel).  Calyx 
strongly  compressed.  Plates  of  the  right  and  left  sides 
large,  those  of  both  the  anterior  and  posterior  small, 
polygonal.  All  plates  perforate,  but  without  pore- 
rhombs.  Ventral  surface  with  three  apertures.  Stem 
composed  of  several  vertical  rows  of  plates.  Cambrian  ; 
Bohemia,  Spain,  Northern  France. 

Mitrocy Stiles  Barr  (Fig.  235).  Like  the  preceding, 
except  that  one  side  of  the  calyx  is  composed  of  toler- 
ably  large,  and  the  other  of  small  plates.  Ordovician ; 
Bohemia. 

Mitrocy  Stella,  Rhipidocystis  Jaekel.  Ordovician ; 
Bohemia. 

Änomalocy Stiles  Hall  (Ateleocystites  Bill.;  Platycystis 
S.  A.  Miller  ;  Enopleura  Weth.).     Calyx  plates  smaller 


Plates 


Mitrocystites  mitra  Barr. 
Ordovician ;  Wosek,  Bohemia. 
Snpposed  right  side  (after 
Jaelcel). 


and  more  numerous 


on  the  convex  side  than  on  the  concave.     Anus  situated  very  low  down  on 


CLASS  I 


CYSTOIDEA 


151 


the  convcx  side.  Arms  feeble,  filiform.  Ordovician  and  Silurian ;  North 
America,  England,  Bohemia. 

Balanocystites  Barr.     Ordovician  ;  Bohemia. 

Belemnocystis  Miller  and  Gurley.     Ordovician  ;  North  America. 

Placocystites  de  Koninck  (Fig.  236).     Silurian  ;  England. 

Dendrocystites  Barrande.  Ordovician  ;  Bohemia.  Cigara  Barrande.  Cam- 
brian ;  Bohemia.     Syringocrinus  Billings.     Trenton  Group  ;  Canada. 

Eocystites  Billings.     Cambrian  ;  Canada. 

Protocystis  Hicks.     Cambrian  ;  England. 

Ceratocystis  Jaekel.     Cambrian  ;  Bohemia. 


Fig.  236. 

Placocystites  forhcsianus  de  Kon.  Silurian  ;  Dudley, 
England.  A,  Concave  aspect,  showing  brachioles  (br) 
and  proximal  stem  joints.  B,  Convex  aspect.  b,  basals  ; 
m,  niarginals  ;  v,  ventrals  (after  Jaekel). 


Fig.  237. 

Amygckducystites  florealis  Bill.  Tren- 
ton Group  ;  Canada.  1,  from  side ;  2, 
Single  plate  enlai-ged ;  3,  portion  of 
food-groove  enlarged.  Br,  dotted 
outline  of  sonie  brachioles ;  Br',  facet 
for  attachment  of  same  (after  Bather). 


Family  3.     Malocystidae  Bather. 

Calyx  plates  numerous  and  indefinitely  arranged.  Radial  folds  of  stereom 
strongly  marked,  hut  no  definite  pore-rhombs  or  peäinated  rhomhs.  Brachioles  borne 
on  processes  either  free  or  recumbent  on  the  calyx.     Stem  uniserial. 

Malocystis  Billings.  Calyx  globular.  Ordovician ;  Canada.  Canadocystis 
Jaekel.     Sanre  horizon. 

Sigmacysiis  Hudson.     Ambulacra  S-shaped.     Ordovician  ;  Canada. 

Amygdalocystites  Billings  (Fig.  237).  Calyx  flattened  and  elongate.  Two 
unbranched  ambulacra,  fringed  with  brachioles,  pass  from  a  subcentral  mouth 
over  the  calyx.     Ordovician  ;  Canada. 

Comarocystites  Billings.  Ordovician ;  Canada.  Achradocystites  Volborth. 
Ordovician ;  Russia. 


Order  2.     RHOMBIFERA  Zittel  (emend.  Bather). 

Radial  symnietry  affects  food-grooves,  and  sometimes  calyx  plates.  Food-grooves 
borne  on  jointed  processes  (brachioles).  Calyx  plates  more  or  less  folded,  and  provided 
with  rhombs. 


152 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


Family  1.     Echinosphaeritidae  Neiimayr. 

Calyx  glohular  or  bursiforni,  adherent  or  with  short  stem,  and  composed  of 
7mmerous,  irregularly  arranged  plates,  all  of  which  are  furnished  with  pore-rhojnhs. 
Ämbulacral  grooves  short,  unhranched ;  arms  two  to  five,free,  biserial,  rarely  preserved. 
Stem,  when  present,  composed  of  several  vertical  series  of  alternately  arranged  plates. 
Ordovician  and  Silurian. 


Fig.  238. 

Echinosphaerites  aurantium  (Hising).  Ordovician  (Vaginatenlvalk) ;  Pulkowa,  Russia.  a,  Summit  view  of 
calyx ;  h,  Calyx  seen  from  the  anal  side ;  c,  Mouth,  arms,  and  covered  ämbulacral  grooves  ;  d,  Calyx  plates 
enlarged,  showing  pore-rhombs  (cf.  Fig.  231). 


Echinosphaerites  Wahlenb.  (Crystallocystis,  Citrocystis,  Trinemacystis  Haeckel) 
(Fig.  238).  Globose,  non-pedunculate.  Mouth  central,  ämbulacral  grooves 
short.  Anal  opening  protected  by  a  valvulär  pyramid ;  arms  unknown. 
Very  abundant  in  the  Ordovician  of  Kussia  and  Scandinavia. 
E.  aurantium  (Hising). 

Arachnocystites  Neumayi-.  Like  the  preceding,  except 
that  it  has  strong  arms,  usually  three  in  number,  which 
sometimes  attain  a  length  of  10  cm.  Stem  tapering  dis- 
tally  to  a  point.  Ordovician ;  Bohemia.  A.  infaustus 
(Barr.). 

Caryocystites  v.  Buch  (Amorphocystis  Jaekel)  (Fig.  239). 
Calyx  plates  relatively  large.  Pore-rhombs  on  external 
surface  elevated,  prominent.  Stem  wanting.  Ordovician  ; 
Eussia,  Scandinavia,  England.     C.  granatum  Wahlenb. 

Palaeocystites  Billings.     Calyx  ovate  or  pyriform  ;  plates 
numerous,  and  porif erous  at  the  margins.   Ordovician ;  Canada. 
Orocystites    Barr.      Ordovician ;    Bohemia.      Heliocrinus   Eichwald.      Ordo- 
vician ;  Eussia.     Stichocystis  Jaekel.     Ordovician  ;  Europe. 


Fig.  239. 

Caryocijstiteis  grana- 
<ttm(Wahlb.)  Ordovi- 
cian ;  Oeland.  Plates 
of  the  natural  size 
showing  elevated 
pore-rhombs. 


Family  2.     Oaryocrinidae  Bernard. 

Calyx  composed  of  a  moderate  number  of  plates  exhibiting  a  more  or  less  definite 
arrangement  in  cycles.  Certain  or  all  of  the  side  plates  with  pore-rhombs  ;  those  of 
the  ventral  surface  imperforate.  Food-grooves  primitively  three,  branching,  and 
leading  to  free  arms  in  varying  number.  Stem  constantly  present,  occasionally  long. 
Ordovician  and  Silurian. 

Hemicosmites  v.  Buch  {Hexalacystis  Haeckel).  Calyx  composed  of  four 
basal  plates,  two  zones  containing  six  and  nine  lateral  plates  respectively,  and 
a  circlet  of  six  plates  forming  the  ventral  surface.  The  latter  carries  three 
short  ämbulacral  grooves,  at  the  ends   of  which   are  situated   small  articular 


CYSTOIDEA 


153 


facets  for  the  attachment  of  arms.     Pore-rhombs  present  on  all  of  the  side 
plates.     Ordovician  ;  Kussia.     H.  pyriformis  v.  Buch. 

Caryocrinus  Say  (Stribalocystis  S.  A.  Miller ;  Enneacystis  Haeckel)  (Fig. 
240).  Calyx  hexamerous,  with  dicyclic  base.  Infrabasals  four,  unequal ; 
followed  by  a  second  row  (basals)  ,^ 

of  six  plates,  alternating  with  the 
plates  of  the  first  and  third  cycles. 
The  latter  ring  consists  of  eight 
plates,  six  of  which,  according  to 
Carpenter,  represent  the  radials, 
and  two  (the  interscapulars  of 
Hall)  the  interradials.  Ventral 
surface  formed  of  six  or  more 
small  pieces.  All  plates  of  the 
cup  furnished  with  pore-rhombs ; 
the  summit  plates  imperforate. 
Mouth  and  ambulacral  groove 
subtegminal.  Anus  protected 
by  valvulär  pyramid,  and  situated 
on  the  outer  margin  of  the  ventral 
surface.  Here  also  are  placed 
the  arms,  which  are  six  to  thirteen 

in    number,    and    relatively   feeble.      Stem    long,    composed    of    cylindrical 
Segments.     Ordovician  ;  Scandinavia.     Silurian  ;  New  York  and  Tennessee. 

Heterocystites  Hall.  Silurian ;  New  York.  Corylocrinus,  Juglandocrinns 
von  Koenen.     Upper  Ordovician  ;  France. 


Fig.  240. 

Caryocrinus  ornatus  Say.  Silurian  ;  Lockport,  New  York. 
(/,  Calyx  from  one  side,  with  two  arms  attached  ;  b,  Summit, 
natural  size  ;  c,  Inner  and  outer  surfaces  of  calyx  plate  of  the 
second  circlet,  with  pore-rhombs. 


Family  3.     Oallocystidae  Bernard. 

Calyx  composed  of  large  plates  arranged  in  three  to  five  cycles,  and  exhibiting 
three  to  five  pectinated  rhombs,  the  component  halves  of  which  stand  on  contiguous plates, 
and  are  separated  by  an  interval.  Mouth  forming  the  centre  of  radi- 
ation  for  two  to  five  brachioliferous  food-grooves  which  are  protected 
by  covering  pieces,  and  either  repose  upon  the  calyx,  or  are  sunk  below 
the  surface  in  grooves.  Stem  well  developed,  tapering  distally  to  a 
point.     Ordovician  and  Silurian. 

n 

Subfamily  A.     Callocystinak  Jaekel. 

Fseudocrinites  Pearce  (Fig.  241).  Calyx  ovate, 
two-  to  four-sided,  and  composed  of  four  cycles 
of  polygonal  plates.  Anus  closed  by  valvulär 
pyramid,  and  occupying  a  lateral  position.  Pore- 
rhombs  three  in  number;  one  placed  above  the 
base,  the  remaining  two  to  the  right  and  left  of 
the  anus.  Arms  two  to  four,  reoumbent  upon  the 
calyx,  extending  to  the  base,  and  beset  with  biserial 
jointed  pinules.     Stem  robust.     Silurian  ;  England. 

Callocystites  Hall  {Anthocystis  Haeckel)  (Fig.  242). 
Calyx  olive-shaped,  the  oral  end  being  more  attenuated  and  obtusely  pointed. 


Fig.  241. 

l'seiuiocrinites  quadrifasciatus 
Pearce.  Silurian ;  Tividale,  Eng- 
land. A,  Calyx  from  one  side. 
B,  Summit,  showing  mouth  (m), 
anus  (o),  and  three  of  the  anns. 
The  foiirth  arm  (i;),  broken  away, 
exposing  flattened  surface  of  calyx. 


154 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


the  base  flat  or  truncated  ;  plates  twenty-five  in  number.     Arms  sometimes 
bifurcating.     Silurian  ;  North  America. 

Apiocystites  Forbes.  Calyx  regularly  oval,  elongate  or  slightly  compressed, 
and  composed  of  nineteen  plates.  Silurian ;  England,  Sweden  and  North 
America. 

Hallicystis  Jaekel.  Like  the  preceding,  except  in  having  five  deltoid 
plates  instead  of  one.     Silurian. 

Lepocrinites  Conrad  (Lepocrinus  or  Lepadocrinus  Hall ;  Staurocystis  Haeckel). 
Silurian  ;  New  York  and  Tennessee. 

Lepadocystis  Carp.  {Meehocystis  Jaekel).     Ordovician  ;  North  America. 

Sphaerocystites  Hall ;  Coelocystis,  Jaekelocystis,  Tetracystis  and  Trimerocystis 
Schuchert.     Silurian  ;  North  America. 

Strohilocystites  White.  Devonian  ;  North  America.  Hybocystites  Wetherby 
Silurian ;  North  America. 


Fig.  242. 

Calloeystites  jewetti  Hall.  Sil- 
urian (Niagara  Group) ;  Lock- 
port, New  York.  Calyx  seen 
from  one  side  (natural  size).  a, 
anus ;  hr,  bracliioles,  j-),  pectino- 
rhombs.     x  §  (after  J  aekel). 


Fio.  243. 

Pleurocystites filüextus  Billings.  Ordovician  ;  Ottawa, 
Canada.  A,  Calyx  from  the  anterior  side.  B,  Same 
from  tlie  anal  side  ;  A,  anal  area  ;  a,  anus  ;  h,  basals  ; 
br,  bracliioles  ;  g,  genital  aperture  ;  l  1-2,  laterals  ;  m, 
madreporite.     x  |  (after  Jaekel). 


Subfamily  B.     Glyptocystinae  Jaekel. 

Pleurocystites  Billings  (Fig.  243).  Convex  side  with  large  plates  arranged 
in  cycles ;  flattened  side  covered  with  very  minute  plates.  Three  isolated 
pore-rhombs  borne  on  the  convex  side.  Arms  two  in  number,  robust.  Stem 
round,  tapering  distally  to  a  point.      Ordovician ;  Canada. 

Glyptocystites  Billings.     Ordovician  ;  Canada  and  Russia. 

Cheirocrinus  Eichwald  ;  Cystoblastus  Yolborth.     Ordovician  ;  Russia. 

Homocystites  Barrande.     Ordovician  and  Silurian  ;  Bohemia. 


Subfamily  C.     Echinoencrininae  Jaekel. 

Echinoencrinus  v.  Meyer  {Sycocystites  v.  Buch  and  Gonocrinites  Eichw.)  (Fig. 
244,  A).  Calyx  composed  of  four  basal  plates,  and  three  cycles  containing  five 
plates  each.     All  calycine  plates  ornamented  with  costae   or  ridges  radiating 


CLÄSS  I 


CYSTOIDEA 


155 


B 


outward  from  the  ceiitre.  Ventral  surface  with  short  ambulacral  grooves,  and 
articular  facets  for  the  attachment  of  three  small  arms.  Anus  removed  to  a 
iateral  position  between  the  first  and 
lecond  circlet  of  side  plates.  Three 
^pore-rhombs  present ;  of  these,  two  are 
situated  above  the  base  on  the  side 
opposite  the  anus,  and  the  third  above 
and  slightly  to  the  right  of  the  anus. 
Stem  round,  short,  tapering  distally 
to  a  point,  and  composed  of  hollow 
Segments  inserted  one  within  the  other 
like  the  draw  -  tubes  of  a  spy-glass. 
Ordovician;  Kussia.  * 

ScoUocystis,  Erinocystis  (Fig.  244,  B) 
and  Glaphjrocystis  Jaekel.  Ordovician  ; 
Russia. 

Prunocystis  Forbes. 

Schizocystis  Jaekel.     Silurian  ;  England 


Fig.  244. 

A,  Echinoencrinus  senckenbergi  v.  Meyer.  B, 
Erinocystis  volhorthi  Jaekel.  a,  anus  ;  h,  basals  ;  l, 
laterals  ;  p,  pectino-rhombs.     x  |  (after  Jaekel). 


Order  3.     DIPLOPORITA  Zittel  (emend.  Bather). 

Radial  symmetry  affects  food-grooves,  and  to  some  extent  the  calyx  plates  connected 
therewith.  Food-grooves  extended  over  the  ccdyx  plates  themselves,  and  prolonged  to 
brachioles  which  line  the  calyx  grooves.  Pectinated  rhombs  and  pore-rhomhs  not 
developed ;  hut  calyx  plates  may  he  folded,  and  diplopores  always  present. 


Family  1.     Sphaeronitidae  Neumayr. 

Calyx  globular  or  cylindrical,  short-stemmed  er  stemless,  and  composed  of 
numerous   irregularly   arranged  plates   with  pores   united  in  pairs.     Ambulacral 

grooves  either  open  or  protected  by 
A  ß  covering  plates,  and  either  short  and 

simple,  or  elongated  and  branching, 
not  extending  from  the  mouth  beyond 
the  adoral  circlet  of  plates.  Arms 
ür«><Ss/2^Tft»r'^  .  ö^s  a  rule  exceedingly  small  and 
primitive.  Ordovician  and  Sil- 
urian. 

Sphaeronites  Hising.  {Pomo- 
cystis  Haeckel)  (Fig.  245).  Glo- 
bose,  stemless.  Five  short  ambu- 
lacral grooves  radiating  from  the 
mouth  towards  the  arm  bases. 
Ordovician  (Vaginatenkalk) ; 
Russia,  Sweden  and  England. 
S.  pomum  Gyll. 

Eucystis  Angelin.      Ordovician  ;  Sweden. 

Trematocystis,  Palmocystis,  Archegocystis  and  Codiacystis  Jaekel.  Ordovician  ; 
Bohemia. 

Allocystites  S.  A.  Miller.     Silurian  ;  North  America. 


Fig.  245. 

Sjihacronites  globulus  Angelin.     Ordovician,  Sweden.     A, 

Theca,  lateral  aspect.     B,  Oral  aspect,  enlarged.    an,  anus  ; 

hr,  facets  for  attachment  of  brachioles  ;  g,  genital  aperture  ; 

0,  mouth  ;  x,  base  for  flxation. 


156 


ECHINODERMATA— PELMATOZOA 


PHYLÜM  IV 


Proteocystites  Barrande.     Lower  Devonian ;  Bohemia.     Carpocystis  Q^hlert. 
Lower  Devonian ;  France. 


Family  2.     Glyptosphaeridae  Bather. 

Food-grooves  extend  over  the  calyx  well  heyond  the  adoral  ärclet,  arid  irregularly 
transgress  the  sutures  between  the  plates.     Diplopores  diffuse. 


Glyptosphaerites  Müll.  (Fig.  228).  DifFers  from  Sphaeronites  in  having 
long,  branching,  ambulacral  grooves,  and  a  short,  well-developed  stem.  Arms 
recumbent  and  grooves  beset  with  small  plates.  Ordovician ;  Eussia  and 
Sweden. 

Fungocystiies  Barrande.     Clavate.     Ordovician ;  Bohemia. 


Family  3.     Protocrinidae  Bather. 

Food-grooves  extend  over  the  calyx  almost  to  the  adoral  pole,  and  are  regularhj 
hordered  hy  alternating  plates  on  which  are  the  brachiole-facets.  Diplopores  diffuse, 
or  confined  to  the  adamhulacrals. 

Frotocrinites  Eichw.   (Fig.   246).     Nearly   hemispherical,  non-pedunculate. 
Ambulacral   grooves    long  and   branching ;    arms   un- 
known.     Ordovician  ;  Russia  and  Bohemia. 

Proteroblastus    Jaekel    (Dadylocystis)     (Fig.     247). 
Ordovician ;  Russia. 


Fig.  246. 

Protocrinites  oviformis  Bichwald.  Ordovician ;  Pulkowa,  Russia. 
a,  Calyx  viewed  from  above ;  h,  Same  from  below  showing  basal 
plate  in  the  centre  (affcer  Volborth), 


Fig.  247. 
Froterohlastus  schmidti  Jaekel. 
Ordovician  ;  Esthonia  ;  anih,  food- 
grooves  ;  hr,  brachioles ;  iamh, 
inter-ambulacrals  ;  o,  mouth  (after 
Jaekel). 


Mesocystis  Bather  (Mesites  Hoflfmann  ;  Agelacrinus  Schmidt).     Ordovician  ; 
Russia. 


Family  4.     Gomphocystidae  Bather. 

Amhuloxra  in  five  main  grooves  curving  around  the  calyx,  and  not  prolonged  to 
the  brachioles. 

Gomphocystites  Hall.  Calyx  flattened  above,  greatly  elongate  below,  com- 
posed  of  many  irregulär  plates,  pierced  by  diplopores.  Covering  plates  often 
developed,  and  grooves  sunk  below  the  thecal  surface.  Silurian ;  North 
America  and  Gotland. 

Pyrocystites  Barrande.     Ordovician  ;  Bohemia. 


CLASS  I 


CYSTOIDEA 


157 


Order  4.     APORITA  Zittel  (emend.). 

Radial  symmetry  affects  food-grooves  and  calyx  plates.  Food-grooves  hörne  on 
processes  aroimd  the  oral  centre.     No  folds,  rhombs  or  diplopores. 

This  division  is  admittedly  artificial  and  ill-defined,  being  chiefly  a 
receptacle  for  genera  whose  relations  are  imperfectly  understood,  or  whose 
systematic  position  is  doubtful. 

Family  1.     Oryptocrinida©  Zittel. 

Calyx  composed  of  three  rings  of  very  finely  perforate  or  imperforate,  somewhat 
regularly  arranged  plates.  Mouth  central,  surrounded  hy  articular  facets  for  the 
attachment  of  small  arms.  Anus  eccentric  ;  stem  round  and 
slender.     Ordovician  to  (?)  Permian.  l    iH 

Cryptocrinus  v.  Buch  (Fig.  248).  Base  composed  of 
three  plates,  and  surmounted  hy  two  zones,  each  con- 
taining  five  plates  of  unequal  sizes.  Mouth  and  anus 
enclosed  within  a  ring  of  smaller  pieces.  Ordovician  ; 
St.  Petersburg.     G.  cerasus  v.  Buch. 

Lysocystites  Miller  (Echinocystites  Hall  non  Wyv. 
Thomson,  Scolocystis  Gregory).  Silurian  (Niagara 
Group) ;  North  America. 

Hypocrinus     Beyrich.       This  a  i 

genus,  described  as  a  Cystid, 
from  the  Permian  in  the  Island 
of  Timor,  and  Coenocystis  Girty, 
from  the  same  formation  in 
western  America,  are  probably 
Crinoids. 


Family  2. 


Macrocystellidae 
Bather. 


Fia.  248. 

Crijptocrinuscerasnsw  Buch. 
Ordovician ;  Pulkowa,  Russia. 
a,  b,  c,  Calyx  from  one  side, 
from  above,  and  from  below 
(nat.  size);  m,  Mouth ;  a,  Anus. 


Fig.  249. 

Macrocystella  manae  Call. 
A,  from  side  x  1/1.  B-D,  por- 
tion  of  a  brachiole,  x8/l, 
from  side,  dorsal  and  ven- 
tral surfaces.  B,  Single  plate 
enlarged  (after  Bather). 


Calyx  consisting  of  three  or  four 
circlets  of  plates,  displaying  more 
or  less  pentamerism.  No  pores  ar 
rhombs.     Cambrian. 

Macrocystella  Calloway. 
(Mimocystites  Barr.)  (Fig.  249).  Three  ranges  of  five  plates  each,  followed 
by  a  fourth  of  the  same  number  bearing  bifurcating  brachioles.  Radiating 
folds  strongly  marked,  dividing  surface  into  triangles.  No  rhomb  structure 
visible.  Stem  rapidly  tapering.  Pentamerous  symmetry  is  well  marked, 
and  the  form  might  be  characterised  as  a  tri-cyclic  Crinoid.  Cambrian  ; 
England. 

Lichenoides    Barr.     (Lichenocystis    Haeckel).       Cambrian ;     Bohemia    and 
Bavaria.     Aethocystis  S.  A.  Miller.     Silurian  ;  Indiana. 

Family  3.     Tiaracrinidae  Bather  (emend.). 

Calyx  composed  of  not  more  tjian  two  circlets  of  plates :  three  (hasdls)  in  the  first, 
and  four  (radials)  in  the  second  ;  followed  hy  a  ränge  of  short  plates  resemhling 


158  ECHINODERMATA— PELMATOZOA  phylum  iv 

brachials  surrounding  the  peripher^  of  the  tegmen,  either  in  an  almost  continuous 
ring,  or  in  groups  where  the  interoral  sutures  meet  the  radials.  Whether  there  are 
further  brachials  in  succession  is  unJcnown.  Stern  with  a  small  axial  canal. 
Silurian  and  Devonian.     Relations  doubtful,  may  be  monocyclic  Crinoids. 

Zophocrinus  S.  A.  Miller,  has  arm  plates  in  Clusters  of  about  three.  Surface 
smooth.     Silurian  ;  North  America. 

Tiaracrinus  Schnitze  {Staurosoma  Barrande).  Arm  plates  eight  or  ten  to 
each  radius,  forming  a  rather  continuous  ring.  Surface  strongly  marked  with 
folds  crossing  the  sutures,  which  seem  to  be  accompanied  by  pores.  Devonian  ; 
Eifel,  France,  Bohemia. 

Order  5.     BDRIOASTEROIDBA   Billings. 

(Syn.  :  Thyroidea  Chapman,  1860;  Agelacrinoidea^.  K.MiWqv,  1877-1883; 
Gystasteroidea  ^tQmm.B:im^  1888;  Bernard,  1893;  Thecoidea  3 a^okeX,  1895). 

The  eminent  Canadian  paleontologist,  E.  Billings,  as  early  as  1854,  called 
attention  to  the  great  difFerence  between  the  forms  now  grouped  under  this 
name  and  the  typical  Cystideans,  and  in  1858  suggested  that  they  should  be 
arranged  as  a  suborder  to  be  called  Edrioasteridae.  Subsequent  authors  have 
generally  agreed  to  this  in  principle,  but  not  as  to  the  relative  rank  which  the 
group  should  have.  Bather,  regarding  it  as  a  class,  assigns  it  equal  rank  with 
the  Cystids,  Crinoids  and  Blastoids.  Jaekel  recognises  it  as  one  of  three 
Orders  into  which  he  divides  the  Cystidea  {sensu  L.  von  Buch),  and  this  pro- 
cedure  is  in  principle  here  adopted,  without,  however,  denying  that  it  may  be 
entitled  to  the  higher  rank.  Bather's  definition  and  general  characterization 
of  the  group  is  substantially  as  follows  : 

Pelmatozoa  in  which  the  theca  is  composed  of  an  indefinite  numher  of  irregulär 
plates,  some  of  which  are  variously  differentiated  in  different  genera  ;  with  no  subvective 
skeletal  appendages,  but  with  central  mouth,  from  which  there  radiate  through  the  theca 
five  unbranched  ambulacra,  composed  of  a  double  series  of  alternating  plates  {covering- 
plates),  sometimes  supported  hy  an  outer  series  of  larger  alternating  plates  {side-plates 
or  flooring -plates).  Pores  between  {not  through)  the  ambulacral  elements,  or  between 
them  and  the  thecal  plates,  permitted  the  passage  of  extensions  from  the  perradial 
water-vessels.  Anus  in  posterior  interradius  on  oral  surface,  closed  by  valvulär 
pyramid.     Hydropore  {usually,  if  not  always,  present)  between  mouth  and  anus. 

This  would  represent  primitively,  as  Bather  explains,  a  form  with  flexible 
sack-like  calyx,  composed  of  numerous  irregulär,  polygonal  plates  deposited 
in  the  integument ;  having  a  mouth  in  the  centre  of  the  upper  surface,  and 
being  attached  by  some  indefinite  portion  of  the  lower  surface.  The  struc- 
ture  of  the  ambulacra  would  remove  it  far  from  the  earlier  Amphoridea, 
among  Cystids,  from  which  group  it  may  haVe  been  derived. 

Upon  this  primitive  ancestral  form  the  following  characters  were,  to  a 
greater  or  less  degree,  impressed :  a  sessile  habit ;  the  consequent  assumption 
of  a  circular,  flattened  form;  the  difFerentiation  of  the  upper  and  under 
surfaces ;  the  development  of  marginals  or  concentric  frame-plates ;  and  the 
tendency  to  increase  the  food-gathering  surface  by  spiral  coiling  of  the  ambu- 
lacra. According  to  the  varying  extent  of  these  modifications,  the  order  is 
divisible  into  three  families  :  Agelacrinidae,  Cyathocystidae,  Edrioasteridae. 

The  Edrioasteroidea  have  a  somewhat  greater  geological  ränge  than  the 


CLASS  I  CYSTOIDEA  159 

majority  of  Cystids,  extending  from  the  Cambrian  to  the  Lower  Carboniferous. 
Two  geriera,  Agelacriniis  and  Edrioaster,  are  fairly  abundant  in  certain  localities 
of  North  America,  but  the  others  are  rare. 

Family  1.     Agelacrinidae  Hall. 

Calyx  composed  mostly  of  thin  plates,  flexible,  attached  temporarily  or  per- 
manently  hy  the  greater  pari  of  the  aboral  surface  ;  ambulacra  confined  to  the  oral 
surface.     Cambrian  to  Carboniferous. 

Agelacrinus  Vanuxem  (Fig.  250).  Calyx  in  the  form  of  a  depressed  or 
convex  disk,  stemless,  and  attached  by  the  entire  under  surface ;  composed  of 
numerous,  small,  polygonal,  usually  imbricating 
plates,  which  are  perforated  by  fine,  usually 
conjugate  pores.  Mouth  surrounded  by  four 
oral  plates ;  radiating  from  this  are  five  small, 
more  or  less  curved  food-grooves,  which  are 
embedded  in  the  disk,  and  are  protected  by  a 
double  row  of  covering  plates.  Ordovician ; 
North  America,  Rhineland  and  Bohemia.  Rare 
in  Silurian  and  Devonian. 

Stromatocystis  Pompeck j.   Cambrian;  Bohemia. 

Cystaster  Hall  {Thecocystis  Jaekel).     Streptaster  fig.  250. 

Hall.       Ordovician  ;    Ohio.  'Agelacrinus  cindnnatiensis  Roemer. 

.       Hemky Stiles  Hall.     Ordovician  and  Silurian  ;    SÄ'Äe  SÄlieÄren'^tJ; 

North  America  and  Bohemia.  ^^^t  of  liafinesqulna  altemata  (Conrad). 

Haplocystis  Roemer.      Devonian  ;  Rhineland. 

Lepidodiscus  Meek  and  Worthen.  Devonian  to  Carboniferous ;  North 
America.     Discocystis  Gregory.     Carboniferous ;  North  America. 

Family  2.     Oyathocystidae  Bather. 

Calyx  composed  on  the  oral  surface  of  five  deltoids  surrounded  by  margmals,  hut 
below  of  a  fused  solid  mass  of  stereom,  with  irregulär  longitudinal  sutures ;  ambu- 
lacra confined  to  oral  surface  ;  permanently  attached  by  the  aboral  surface,  as  by  an 
encrusting  roof.     Ordovician. 

Cyathocystis  Schmidt.     Ordovician  ;  Esthonia. 

Family  3.     Edrioasteridae  Bather. 

Calyx  flexible,  composed  of  thin  plates ;  attached,  if  at  all,  by  a  small  central 
portion  of  the  aboral  surface  ;  ambulacra  pass  on  to  the  aboi'al  surface.  Ordovician 
to  Devonian. 

Edrioaster  Billings  (Aesiocystis  Miller  and  Gurley)  (Fig.  251).  Ordovician ; 
Canada  and  Kentucky. 

Dinocystis  Bather.     Devonian  ;  Belgium. 

^  Cyclocystoides  Billings  and  Salter.  Ordovician  ;  North  America  and  Great 
Britain.  Probably  a  Cystid,  but  not  sufficiently  known  to  be  assigned  to  any 
particular  family. 


160 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


Family  4.     Steganoblastidae  Bather. 

Calyx  rigid,  composed  of  plates  relatively  larger  and  thicker  than  in  other 
f amilies  of  this  group,  including  elemenfs  comparable  to  the  radials  and  basals  of 
Blastoidea.    Ämbulacra  descend  into  the  radials.    Ä  short  stem  present.     Ordovician. 

SteganoUastus  Whiteaves  (originally  described  as  Astrocystites,  name  pre- 
occupied).  In  all  the  prominent  external  characters  resembling  a  Blastoid, 
but  careful  study  of  the  type  specimens  by  Bather  has  shown  the  ämbulacra 
to  have  essentially  the  same  structure  as  in  Edrioaster,  and  that  brachioles  are 
absent.     Ordovician  ;  Canada. 


am 


P     anit   yg    gj 


Fio.  251. 

Edrioaster  bigsbyi  Bill.  Ordovician  ;  Ottawa,  Canada.  1,  Oral  surface  with  covering  plates  (amh)  on  two 
of  the  grooves,  and  side-  or  flooring-plates  {ad)  on  the  others,  x  1/1.  2,  Vertical  section  of  same,  1/1.  3,  Sec- 
tion  across  an  ambulacrum,  enlarged.  Ad,  flooring-plates  ;  amb,  covering-plates ;  as,  anus ;  ia,  interambu- 
lacrals  ;  M,  madreporite  ;  m,  membrane  with  imbricating  plates,  thrown  into  live  lobes  (0  ;  /,  frame  of  stouter 
plates  ;  ps,  subtegminal  peristome  ;  2\  pores  ;  vg,  ventral  groove  (after  Bather). 


The  following  generic  names  have  been  incorrectly  applied  to  Cystids  : 

Ascocystües  Barrande.     Probably  a  Camerate  Crinoid. 

Camarocrinus  Hall.       {Lobolithus  Barr.).       Inflated   or   bulboiis   root  of  the    Camerate 
Crinoid,  Scyphocrinus. 

Cardiocystis  Barrande.     Indeterminable. 

Orinocystis  Hall.     Probably  a  Camerate  Crinoid. 

Cyclocrinus  Eichwald  (Pasceolus  Billings).     Not  an  Echinoderm, 

Dictyocrinus  Conrad.     A  Receptaculite. 

Hyponome  Loven.     The  ejected  disk  of  a  Comatulid. 

Lichenocrinus  Hall.     The  terminal  stem-plate  or  root  of  some  Pelmatozoan. 

Neocystites  Barrande.     Probably  the  root  of  a  Pelmatozoan. 

Forocrinus  Billings.     An  Inadunate  Crinoid. 


Range  and  Distribution  of  the  Cystoidea. 

The  Cystideans,  a  wholly  extinct  class,  are  the  oldest  known  members  of 
the  Pelmatozoa.  They  are  represented  in  the  Cambrian  by  a  number  of  poorly 
preserved  forms,  whose  affinities  are  in  many  cases  doubtful  {Protocystites, 
Macrocy Stella,  Eocystites,  Lichenoides,  Trochocystites).  They  attain  their  maximum 
development  in  the  Ordovician  and  Silurian,  whereupon  they  suddenly  dimiiiish 
in  numbers,  and  probably  disappear  in  the  early  Carboniferous.  Of  the  250 
species  that  have  been  described,  scarcely  a  dozen  are  found  in  strata  above 
the  Silurian. 


CLAss  II  BLASTOIDEA  161 

Although  a  fcvv  forms  (EchinosphaeriteSj  Aristocystites,  Caryocystites)  appear 
in  considerable  abuudaiice  in  certain  formations,  and  are  locally  profuse  in 
some  beds,  the  majority  are  of  comparatively  rare  occurrence.  The  brachioles 
are  only  exceptionally  preserved,  owing  to  their  fragile  Constitution,  and  the 
stem  is  also  usually  lost. 

Cystideans  are  found  most  plentifully  in  the  Ordovician  rocks  of  St. 
Petersburg,  Russia,  and  in  the  Silurian  localities  of  Oeland,  Gotland,  Sweden, 
Wales  and  Bohemia  (fitage  D).  The  Bohemian  specimens  are  usually  pre- 
served in  the  form  of  casts  and  moulds,  and  are  contained  in  siliceous  or 
argillaceous  slates.  The  Chazy  and  Trenton  limestones  of  Canada,  New  York, 
Ohio  and  Indiana  also  yield  a  large  variety  of  forms. 

Excellently  preserved  specimens  of  Fseudocrinites,  Apiocystites,  Echinoen-^ 
crinus  and  Anomalocystites  are  obtained  from  the  Silurian  limestones  of  Dudley 
and  Tividale,  England ;  and  similar  forms  (Lepadocrinus,  Callocystites,  Caryo- 
crinus)  are  found  in  the  Silurian  (Niagara  Group)  of  North  America.  Only 
scanty  remains  are  known  from  the  Devonian,  and  from  the  Lower  Carboni- 
ferous  but  a  single  genus,  Lepidodiscus. 

Two  genera  have  been  described  from  the  Permian,  Hypocrinus  Beyrich, 
and  Coenocystis  Girty;  but  their  systematic  position  is  doubtful,  and  until  more 
is  known  of  their  strukture  they  may  be  left  out  of  consideration. 

Olass  2.    BLASTOIDEA  Say.i 

Extind,  short-stemmed,  or  stemless  Pelmatozoa  with  a  rigid  calyx  resemhling  a 
flower-bud  in  shape,  witK  pentamerous  symmetry  predominant  (occa^ionally  modified 
hy  atrophy),  usually  composed  of  thirteen  principal  plates.  Food-grooves  lying  in 
lanceolate  or  linear  areas  {amhulacra  or  pseudambulacra)  which  radiale  from  a 
central  perisfome  hetween  five  interradial  deltoid  plates  and  are  not  crossed  hy  sutures 
hetween  calyx  plates  ;  they  hear  at  their  lateral  margins  pinnule-lihe  appendages,  and 
from  their  inner  floor  hang  lamellar  tubes  known  as  hydrospires.  Grooves  and  peri- 
stome  protected  by  small,  movable  covering 


The  calyx  is  clavate,  pyriform,  ovate  or  globose,  frequently  pentangular 
at  its  Upper  face,  and  composed  of  plates  which  are  firmly  united  among 
themselves.  The  plates  of  the  abactinal  System  are  arranged  in  three  suc- 
cessive  cycles,  represented  by  the  basals,  radials  and  interradials  or  deltoids. 
The  plates  of  the  actinal  system  comprise  the  summit  plates  and  the  ambulacra. 

The  basals  consist  of  two  plates  of  equal  size,  and  a  third  smaller  one, 
which  is  directed  invariably  toward  the  right  anterior  interradius.  Resting 
upon  the  basals  are  five  V-shaped,  usually  equal  radials  (commonly  known 

^  Literatiire  :  Say,  T.,  Ohservations on  some  Species of  Zoophytes,  etc.  Amei\  Journ.  Sei.,  1820, 
vol.  ii. — Say,  T.,  On  two  Genera  and  several  Species  of  Crinoids.  Journ.  Acad.  Nat.  Sei.  Philad., 
1825,  vol.  iv.  (Also  in  Zool.  Journ.,  1825,  vol.  ii.) — Roemei\  F.,  Monographie  der  fossilen 
Crinoidenfamilie  der  Blastoideen.  Troschel's  Archiv  für  Naturgesch. ,  1851,  Jahrg.  xvii.,  vol.  i. — 
Jiofe,  J.,  Notes  on  Echinodermata.  Geol.  Mag.,  Dec.  1,  1865,  vol.  ii. — Billings,  K,  Notes  on  the 
Structure  of  Crinoidea,  Cystoidea,  and  Blastoidea.  Amer.  Journ.  Sei.  2nd  ser.,  1869-70,  vols. 
xlviii.-l. — Etheridge,  R.,  and  Carpenter,  P.  IL,  Catalogue  of  the  Blastoidea  in  the  Geological 
Department  of  the  British  Museum,  1886.  [Complete  bibliogi-aphy,  pp.  303-310.]— ßo^/jgr,  F.  A., 
Genera  and  Species  of  Blastoidea,  with  a  list  of  specimens  in  the  British  Museum,  1899.  [Complete 
index  of  names  with  references  to  literature.] — Bather,  F.  A.,  Treatise  on  Zoology  (Lankester). 
Part  III.,  Echinoderma,  1900. — Hambach,  G.,  Revision  of  the  Blastoidea.  Trans.  Acad.  Sei. 
St.  Louis,  1903,  vol.  xiii. — Hitdson,  G.  H.,  Pelmatozoa  from  Chazy  Limestone.  New  York  State 
Museum  Bull.  No.  107,  1907. 

VOL.  I  M 


62 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


as  ^^forked  plates  "),  whose  superior  margins  are  more  or  less  deeply  incised  by 
the  radial  sinuses.     The  term  sinus  is  applied  to  the  open  space  between  the 

two  prorigs  or  limhs  of  the  plate  (Fig.  252). 

Succeeding  and  alternating  with  the  radials, 
and  resting  upon  their  limbs,  are  five  interradial 
or  deltoid  plates,  which  vary  excessively  in  size ; 
they  are  considered  to  be  homologous  with  the 
oral  plates  of  the  Crinoids.  In  some  species  they 
occupy  a  large  part  of  the  sides  of  the  calyx,  and 
in  others  they  are  confined  to  the  upper  face. 
In  Nudeocrinus  and  certain  species  of  Orhitremites, 
the  deltoids  extend  down  so  far  into  the  calyx  as 
to  constitute  more  than  half,  or  nearly  the  whole 
of  its  sides,  while  the  radials  are  so  short  as  to 
be  almost  invisible  in  a  side  view.  Only  a  part 
of  the  deltoids  is  exposed  to  view,  their  sides 
being  provided  with  flanges  which  are  covered 
by  the  outer  ends  of  the  ambulacra.  The  name 
deltoid  has  reference  to  the  exposed  part  of  the  plates,  which  in  most  forms 
is  triangulär  or  rhomboidal  in  outline. 

The  radial  sinuses  between  the  limbs  of  the  radials  and  the  super jacent 
deltoids  are  filled  by  the  ambulacral  fields  or  ambulacra  (^' pseudambulacra  "  of 
Roemer).  The  ambulacra  vary  in  form  from  petaloid  to  narrow  lanceolate  or 
linear,  and  extend  from  the  summit  of  the  calyx  to  the  distal  ends  or  lij)S  of 
the  radial  sinuses.  The  open  space  in  which  the  ambulacra  meet,  the  so-called 
'*  summit- opening  "  or  peristome,  is  pentangular,  and  central  in  position.  Ordin- 
arily  this  space  is  open,  but  in  well-preserved  specimens  it  is  covered 
by  a  greater  or  less  number  of  minute  calcareous  pieces  (Fig.  253);  these 


Fig.  252 
Pentremites  godoni  (Defr.J. 
of  calyx.     h,  Basais  ; 
Interradials  or  deltoids 


Analysis 
Radials ;   ir, 


Fig.  253. 

A,  Orhitremltes  norwoodi  (O.  and  S.).  Upper  face  of  perfect  specimen,  with  inouth  and  anus  (a)  closed  by 
plates.  Spiracles  {sp)  separate.  B,  Orophöcrinus  stelliformis  (O.  and  S.).  Upper  face  with  closed  peristome  and 
exposed  anus.  Spiracles  slit-like.  C,  FeMremites  sulcatus  Roem.  Central  mouth-opening  surrounded  by  five 
spiracles,  the  posterior  one  confluent  with  the  anus.  D,  Cryptohlastus  melo  (O.  and  S.).  Upper  face  with 
central  mouth-opening,  large  anus,  and  eight  spiracles  (after  Carpenter).  All  specimens  from  Burlington 
Group;  Iowa. 

may  be  either  regularly  or  irregularly  arranged,  but  leave  at  each  angle  of 
the  summit-opening  a  small  passage-way,  by  means  of  which  the  ambulacra 
communicate  with  the  peristome.     The  mouth  is  invariably  subtegminal. 

The  summit  structure  is  rarely  observed.  The  small  plates  which  cover 
the  peristome  are  merely  extensions  of  the  ambulacral  covering  plates  variously 
modified  in  shape.  In  Nudeocrinus,  Orophöcrinus  and  Schizoblastus  sayi,  the 
central  Space  is  occupied  by  five  asymmetrical  plates,  formerly  called  orals, 
surrounded  by  smaller  ones  toward  the  grooves.     In  Orbitremites  norwoodi  and 


l., 


BLASTOIDEA 


163 


Cryptohlastus  meto  the  plates  are  all  small  and  irregularly  arranged.  In  the 
genus  Pmtremites  the  covering  plates  are  modified  in  a  singularly  different 
way  :  toward  the  centre  they  become  increasingly  elongate  and  spine-like, 
suiTounding  not  only  the  central  opening,  but  also  the  spiracles  and  anal 
aperture,  with  a  fringe  of  tapering  spines,  which  meet  over  the  summit  in  a 
tuft-like  stellate  pyramid,  with  salient  angles  interradial. 

The  summit  in  most  Blastoids  is  surrounded  by  a  cycle  of  five  pairs  of 
openings ;  and  between  the  two  posterior  ones  there  is  usually  interposed 
a  Single  additional  aperture.  The  former  were  regarded  by  Roemer  as  con- 
nected with  the  genital  System,  and  were  called  by  him  "  ovarian  apertures " ; 
but  they  are  now  known  as  the  spiracles.  The  other  opening  which  pierces 
the  Upper  end  of  the  posterior  deltoid  is  the  anus. 

The  form  and  arrangement  of  the  spiracles  is  extremely  variable ;  they 
may  be  round  or  slit-like ;  they  may  consist  of  ten  separate  openings,  or  those 
of  the  same  pair  may  be  con-  ^  ß 

fluent  with  one  another.    The  J 

members  of  the  posterior  pair 
may  be  fused  with  each  other 
and  with  the  anus,  in  which 
case  the  fifth  or  posterior 
spiracle  is  considerably  larger 
than  the  others.  Orbitremites, 
Fentremites,  Pentremitidea,  etc. 
(Fig.  254,  A),  are  examples  of 
the  latter  case ;  Orbitremites 
having  five  circular  orifices 
with  tube  -  like  projections, 
while  in  Pentremites  and  Pent- 
remitidea the  four  smaller 
spiracles  are  divided  into  two 
compartments  by  the  terminal 
median  ridge  of  the  deltoids. 
The  posterior  spiracle  in  the 
two  latter  genera  is  divided 


A,  Pentremi 


Fig.  254. 
godoni  (Defr.).  Lower  Carboniferous ;  Alabama. 
Upper  face  with  ambalacral  fields  in  various  states  of  preservation. 
a,  Ambulacrum  after  the  removal  of  lancet-  and  side-plates  ;  hydro- 
spires  exposed  ;  b,  Lancet-plate  with  upper  surface  denuded  by 
weatliering ;  c,  Perfectly  preserved  lancet-plate  bordered  by  side- 
plates  ;  d,  The  same,  but  with  transverse  markiiigs  of  lancet-plate 
obliterated  ;  e,  Ambulacrum  covered  with  pinnules  (after  Roemer), 
B,  Fhaenoschisma  acutum  (Swhy.)  Lower  Carboniferous  ;  Lancashire. 
Upper  face,  enlarged  ;  a,  Ambulacrum  after  removal  of  the  lancet- 
and  side-plates  ;  hydrospire  slits  (Jiy)  cutting  through  radials  and 
deltoids ;  h,  c,  Ambulacra  in  which  lancet-plates  (l)  only  are  pre- 
served :  d,  e,  Ambulacra  intact ;  lancet-plate  concealed  by  side-plates 
(after  Etheridge  and  Carpenter). 


by  a  duplicate  ridge  into  three 
compartments ;  of  these  the  middle  one  enters  the  inner  cavity,  and  the  two 
outer  ones  communicate  with  the  hydrospires  by  means  of  the  hydrospire 
canal.  In  Troostocrinus,  Schizoblastus  and  Cryptoblastus  (Fig.  253,  B)  the 
posterior  spiracles  are  confluent  with  the  anus,  while  those  of  the  four  regulär 
sides  are  separated.  Nudeocrhius,  Mesoblastus  and  Acentrotremites  have  ten 
separate  spiracles,  and  a  large,  distinct  anal  aperture.  The  typical  Codasteridae 
(Codaster  and  Phaenoschisma),  in  which  the  hydrospires  are  exposed  externally, 
have  no  spiracles  and  no  hydrospire  canal.  Orophocrinus  (Fig.  253,  B)  has 
ten  elongate  clefts  extending  along  the  sides  of  the  ambulacra ;  but  these  are 
in  reality  the  unclosed  portions  of  the  radial  sinuses,  and  correspond  to  the 
open  hydrospire  canals  of  Pentremites,  which  are  apparent  upon  the  removal  of 
the  side-plates. 

The  ambulacra  are  usually  depressed  below  the  general  level  of  the  calyx, 
but  are  sometimes  raised  above  it,  or  they  may  be  placed  in  the  same  plane 
with  it.     They  vary  in  form  from  narrow  linear  to  broad  petaloid,  and  are 


164 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


considerably  complicated  in  structure  (Fig.  255).  The  centre  of  each  ambu- 
lacrum  is  occupied  by  the  lancet-plate,  a  long,  narrow  piece,  pointed  at  both 
ends,  which  extends  to  the  füll  length  of  the  fields.  Its  proximal  end  is 
inserted  between  the  deltoids,  and  takes  part  in  the  lip  around  the  summit- 
opening.     The  upper  surface  of  the  plate  is  excavated  along  the  median  line, 

and  forms  an  open,  well-defined  groove,  which 
conducts  to  the  mouth,  and  in  all  probability 
represents  the  food-groove.  The  interior  of  the 
plate  is  traversed  by  an  axial  canal,  which  com- 
municates  by  means  of  the  ambulacral  opening 
with  an  oral  ring  belonging  to  the  water-vascular 
System.  In  a  number  of  forms  (Fentremites, 
Orophocrinus)  there  is  to  be  seen  a  second, 
smaller,  and  extremely  thin  plate  underlying 
the  median  portion  of  the  first ;  this  is  called 
the  unde7'  lancet-plate. 

The   lancet-plate   rarely   occupies    the    füll 

width  of  the  ambulacral  field,  and  the  spaces 

'^^^'-  2''^-  between  its  lateral  edges  and  the  sides  of  the 

o,i^^^;^Z^1^;^i!^^S^  radial    sinus    are    either    wholly    or    partially 

plate  {}) ;  median  food-groove  of  the  same  covered  bv  a  row  of  small,  horizontally  elongated 

(ci) ;  side-plates  (s) ;  oiiter  side-plates  (e) ;  i    ,        /cc  i   ^      v      c    -r>  \        t        r.      ^ 

and  marginal  pores  (p),  5/i,  (after  B.  and  stde-plates  (" pore-plates    Ol  Koemer).     In  Feiit- 

C).    -B.    Ambulacrum    of    Nuckocrinus.  -j        r\        i         •  ^      i-i  n  t 

Lettering  as  in  ^  (after  Roemer).  vemites,  Orophocnnus,  and  other  genera,  an  addi- 

tional  series  of  still  smaller  pieces,  called  the 
outer  side-plates  (^^ supplementär y  pore-pMes"  of  Roemer),  are  placed  between 
the  side-plates  and  the  walls  of  the  radial  sinus.  Fentremites  and  Cryptoschisma 
have  the  entire  upper  surface  of  the  lancet-plate  exposed  to  view,  and  the 
side-plates  are  situated  alongside  of  it  in  the  a 
same  plane.  But  in  other  forms  the  lancet-plate 
is  wholly,  or  to  a  very  large  extent,  concealed  by 
the  side-plates  (Fig.  255,  B),  so  that  as  a  rule 
only  a  small  space  along  the  food-groove  is  visible. 
The  sutures  between  the  side-plates  are  indicated 
by  shallow,  horizontal  furrows,  which  are  con- 
tinued  as  superficial  grooves  over  both  halves  of 
the  lancet-plate  as  far  as  the  median  ambulacral 
groove.  These  crenulations,  it  should  be  noted, 
are  frequently  effaced  in  weathered  specimens 
(Fig.  255,  ^  and  B).  Small,  pit-like  depressions, 
or  small  tubercles,  which  are  observable  on  the 
side-plates,  indicate  the  places  where  the  append- 
aeres  or  pinnules  were  f ormerlv  attached.   These  are  perfoctiy  preserved  pinnuies  (afte/Meek 

1  X-         ^^      £         j    ■  \.      j.     ^     ^        i  and  Worthen). 

only  exceptionaily  lound  nitact,  but  when  pre- 
served they  completely  conceal  the  ambulacral  fields,  and  extend  upward  above 
the  summit  of  the  calyx  (Fig.  256).  They  difFer  considerably  in  length,  even 
among  species  belonging  to  the  same  genus.  They  are  jointed  structures  like 
miniature  arms,  uniserial  as  far  as  observed,  but  with  ossicles  sometimes 
wedge-shaped  and  interlocking  to  some  extent  from  opposite  sides,  thus 
simulating  a  biserial  arrangement.  Whether  they  performed  the  function  of 
discharging  the  ova,  like  the  pinnules  of  Crinoids,  can  only  be  conjectured. 


Fig.  256. 


a,  Pinnule  of  Fentremites,  enlarged  ; 
Orhitremites  norwoodi  (O.  and  S.)  with 


l.,, 


BLASTOIDEA 


165 


The  crenulations,  or  file-like  markings  across  the  ambulacra  in  Pentremites 
above  iioted,  are  not  mere  surface  ornamentation ;  but  the  ridges  constitute 
the  sides,  and  the  depressions  the  floor,  of  a  series  of  small  ducts  leading  from 
the  pinnules,  and  forming  lateral  branches  of  the  main  ambulacral  groove 
into  which  they  discharge.  These  lateral  ducts,  as  well  as  the  main  median 
groove  of  the  ambulacrum,  are,  in  well-preserved  specimens,  roofed  over 
throughout  the  entire  field  by  very  minute  alternating  covering  plates  extend- 
ing  all  the  way  to  the  pinnules,  and  probably  continuing  along  their  ventral 
side.  In  this  respect  the  structure  of  the  ambulacral  area  has  not  been 
generally  understood,  and  not  heretofore  correctly  described.  The  arrange- 
ment  of  the  side  ducts,  their  discharge  by  a  distinct  curvature  into  the  main 
groove,  and  their  connection  with  the  pinnules,  leave  no  doubt  that  they 
were  the  closed  food-grooves  serving  to  conduct  nutriment  from  the  pinnules 
on  toward  the  mouth. 

In  most  Blastoids  the  side-plates,  or  the  outer  side-plates  when  such  are 
present,  are  pierced  by  marginal  pores  (or  hydrospire  pores),  which  communicate 
with  the  hydrospires.  The  pores  are  situated  at  the  extreme  outer  margins 
of  the  plates,  at  the  end  of  the  lateral  ridges,  and 
alternate  in  position  with  the  sockets  of  the  pinnules. 
They  are  present  in  all  forms  having  the  hydrospires 
concealed  within  the  calyx ;  but  are  absent  in  the 
Codasteridae,  in  which  the  hydrospires  are  wholly  or 
in  part  exposed  on  the  outer  surface. 

The  hydrospires  (Figs.  257,  258)  are  bundles  of 
flattened,  lamellar  tubes,  extending  underneath  the 
lancet-  and  side-plates,  in  a  direction  parallel  with 
the  boundaries  of  the  ambulacral  fields.  They  begin 
at  the  lower  end  of  the  ambulacra,  and  terminate  in 
the  hydrospire  canals,  of  which  the  spiracles  form  the 
adoral  apertures.  When  the  spiracles  are  confiuent, 
the  canals  of  adjacent  groups  of  hydrospires  enter  the  J; 

same  opening.  The  hydrospires  are  suspended  in  the  Vs^^the  hdght  «f^tue^^^^bi^^^^^^^ 
majority  of  forms  along  the  walls  of  the  body-cavity  i,  LaAcet-piate ;  p,  Pore-piates; 
(Pentremites,  Fig.  257),  being  attached  either  to  the  ^' 

outer  margins  of  the  under  lancet-plate  or  to  a  separate  piece  known  as  the 
hydrospire  plate  (Orbitremites,  MesoUastus  and   Cryptohlastus).      Pentremites  has 


--^^..f 


Pentremites  sulcatusSaj.  Lower 
Carboniferous ;    Illinois.     Trans- 
erse  section  of  calyx  at  about 


mps)^ 


Fig.  258. 
Transverse  sections  through  the  ambulacral  fields,  showing  various  forms  of  hydrospires.     A,  Orhitremites 
derhijemis.     B,  Orbitremites  nonoooiU.     C,  Metablastus  lineatus.    D,  OropTiocrinus  verus.    All   sections  enlarged 
(after  Etheridge  and  Carpenter). 

from  f our  to  nine  hydrospires  in  each  group  ;  Orhitremites  two,  or  exceptionally 
one ;  Troostocrinus  and  MesoUastus  generally  three,  and  Orophocrinus  from  five 
to  seven  (Fig.  258,  A-D).     In  Phaenoschisma  and  Codaster  (Fig.  260)  the  tubes 


166  ECHINODERMATA— PELMATOZOA  phylüm  iv 

open  externally  by  slits  piercing  the  radials  and  deltoids  and  running  parallel 
with  the  ambulacra. 

The  functions  of  the  hydrospires  can  only  be  surmised,  but  they  are  sup- 
posed  to  have  served  for  respiration  :  they  correspond  doubtless  to  the  pec- 
tinated  rhombs  and  calycine  pores  of  the  Cystideans  and  to  the  respiratory 
pores  of  some  Crinoids.  It  is  probable  that  water  was  admitted  to  the 
hydrospire  sacs  through  the  marginal  pores,  and  was  discharged  through  the 
spiracles.  Roemer  and  Forbes  have  suggested  that  the  hydrospires  may 
also  have  performed  reproductive  functions.  Ludwig  has  called  attention  to 
the  resemblance  between  the  genital  bursae  of  Ophiuroids  and  the  slit-like 
spiracles  in  Orophocrinus ;  his  theory  is  that  the  hydrospires  served  both  for 
purposes  of  respiration  and  for  the  discharge  of  genital  products,  a  view 
which  was  also  shared  by  Carpenter. 

The  stem  in  Blastoids  is  preserved  only  in  exceedingly  rare  instances.  It 
is  round,  provided  with  a  small  axial  canal,  and  composed  of  short  joints, 
which  apparently  multiplied  in  a  similar  manner  to  that  in  the  Crinoids.  In 
Orophocrinus  and  Pentremites  it  has  been  traced  for  a  length  of  15  cm.  without 
reaching  the  end;  and  in  the  latter  form  it  has  occasionally  been  found  with  a 
few,  comparatively  heavy  cirri.    A  f ew  genera,  like  Eleutherocrinus,  are  stemless. 

It  has  frequently  been  claimed,  owing  to  the  superficial  resemblance  of 
their  ambulacral  areas,  that  the  Blastoids  and  Echinoids  are  mutually  related ; 
but  such  presumptions  are  founded  upon  a  total  misconception  of  the  value 
of  external  characters.  The  construction  of  the  calyx,  the  presence  of  pin- 
nules,  and  the  stemmed  condition,  are  features  which  identify  them  unmis- 
takably  as  Pelmatozoa ;  and  their  nearest  relatives  under  this  group  are  the 
Cystideans.  The  parallelism  between  the  ambulacral  fields  of  the  one  class 
and  the  recumbent  arms,  apparently  soldered  on  to  the  calyx  of  the  other,  is 
self-evident.  The  hydrospires  of  Blastoids  correspond  to  the  pore-rhombs  of 
Cystideans,  as  has  already  been  remarked ;  and  the  position  of  the  mouth  and 
anus  is  the  same  in  both  types.  The  Blastoids  constitute  a  peculiar,  but,  on 
the  whole,  a  very  well-defined  group,  which  is  now  regarded  as  of  equal  rank 
with  the  Crinoids  and  Cystids. 

:  The  earlier  forms  occurring  in  the  Ordovician  are  primitive,  representing 
transitions  from  ancestors  of  Cystid  type,  and  having  the  characters  of  the 
two  groups  intermingled  in  varying  degrees.  In  one  genus,  Asterohlastus,  the 
presence  of  diplopores  and  lack  of  hydrospires  are  correlated  with  the  presence 
of  the  Blastoid  ambulacrum  together  with  its  bordering  pinnules,  and  more 
strongly  developed  basals  and  radials.  In  another,  Blastoidocrinus,  the  diplo- 
pores are  replaced  by  hydrospires,  thus  further  strengthening  a  line  of 
development  which  becomes  thoroughly  established  in  the  Silurian  with  the 
genus  Troostocrinus. 

Several  genera  are  represented  in  the  Devonian,  both  of  Europe  and 
America.  But  the  climacteric  of  Blastoid  development  takes  place  in  the 
Lower  Carboniferous  of  North  America ;  some  of  the  beds  of  the  Kaskaskia 
Group  are  densely  charged  with  their  remains,  which,  as  a  rule,  are  excellently 
preserved.  They  occur  sparsely  in  the  Upper  Carboniferous  and  Permian  of 
western  America  and  the  island  of  Timor,  but  above  this  horizon  no  traces  of 
Blastoids  have  as  yet  been  discovered.  Nineteen  genera,  comprising  upward 
of  120  species  were  recognised  by  Etheridge  and  Carpenter  in  their  mono- 
graph  of  1886,  and  a  few  have  been  added  since. 


OLASS  II  BLASTOIDEA  167 

The  last-named  authors  subdivided  the  Blastoids  into  Begulares  and 
Irreguläres,  an  arrangement  representing  incidental  Variation  rather  than  any 
broad  morphological  differentiation.  That  presented  by  Bather  in  Part  III. 
of  Lankester's  Zoology,  1899,  appears  to  be  more  logical,  and  is  followed  in 
principle  here.  By  separating  the  typical  Blastoids,  in  which  the  character- 
istic  calyx  plates  have  become  fixed  at  a  small  and  definite  number,  from  the 
earlier  forms  which  have  not  attained  that  structure,  two  main  divisions  may 
be  recognised,  viz. :  ProtoUastoidea  and  EuUastoidea.  Hudson,  whose  admirable 
studies  upon  Blastoidocrinus  have  thoroughly  elucidated  that  hitherto  obscure 
type,  has  suggested  a  third,  FaraUastoidea,  to  express  the  differences  shown  by 
his  researches  between  it  and  the  other  Ordovician  forms.  As  the  general 
division  is  a  somewhat  arbitrary  one  at  best,  it  is  thought  that  these  differences 
are  sufficiently  emphasised  by  the  family  diagnosis. 

Order  1.     PROTOBLASTOIDBA   Bather  (einend.) 
Calyx  plates  numerous,  not  limited  to  a  definite  numher. 

Family  1.     Asteroblastidae. 

Blastoidea  with  calyx  plates  indefinitely  arranged  ahove  basals  and  radials,  and 
having,  along  wiih  pentamerous  ambulacra 
ami    marginal    hrachioles,    diplopores    and 
pore-plate,  hut  no  hydrospires.     Ordovician. 

Asterohlastus  Eichw.  (Fig.  259).  Calyx 
gemmiform,  pentagonal,  pedunculate,  and- 
composed  o£  numerous  rigidly  united 
plates  which  are  perforated  by  conjugate 
pores.     Upper  surface   marked   by   five  fig.  259. 

lircTP     r»ptnlm'rl      nr     efpllnfp     araaa     wVnVli  Asterohlastus  stellatus  Eichw&lA.     Ordovician; 

large    petalOia     Or    Stellate     areas    Wtlicn       Puikowa,  Russia.     Natural  size  (after  Schmidt). 

are  occupied  by  alternating  plates,  and 

bordered  by  sockets  for  the  attachment  of  brachioles.     Ordovician ;  Russia. 

Family  2.     Blastoidocrinidae  Bather  (emend.). 

Calyx  plates  more  definitely  arranged  in  four  ciixlets,  without  diplopores  or  pore- 
plate,  hut  with  hydrospires  present.     Ordovician. 

Blastoidocrinus  Billings  (emend.  Hudson).  Calyx  pentagonal,  composed  of 
four  circlets  of  principal  plates,  viz.  :  (1)  basals  (number  unknown) ;  (2) 
radials  with  angular  distal  face,  followed  by  (3)  two  large  plates  called  bi- 
brachials,  with  numerous  interbrachials  in  each  interradius ;  and  (4)  very 
large  triangulär  deltoids,  with  hydrospire-slits  at  their  lower  margins 
Adambulacrals,  heavy  covering  plates,  and  some  additional  plates  in  the  oral 
portion.  Ambulacra  large,  bordered  with  numerous  brachioles  or  pinnules. 
Base  invaginate,  with  strong  column  occupying  the  concavity.  Ordovician 
(Chazy  Group) ;  Canada  and  New  York. 

Order  2.     EUBLASTOIDEA   Bather. 

Calyx  plates  limited  to  a  definite  numher  of  ahout  thirteen.  Hydrospires  always 
present. 


168 


ECHINODEEMATA— PELMATOZOA 


PHYLUM  IV 


Family  1.     Oodasteridae  Etheridge  and  Carpenter. 

Base  usually  well  developed,  and  sometimes  very  long.  Amhulacra  without 
marginal  pores.  Hydrospire-folds  Coming  to  the  surface  of  the  radial  sinus. 
Hydrospire-slits  either  wholly  exposed,  piercing  the  calyx  plates  along  the  sides  of 
the  radial  sinuses,  or  restrided  portions  of  them  remain  open  as  spiracles,  white 
the  remaining  parts  are  concealed  hy  the  amhulacra.  Devonian  and  Lower 
Carboniferous. 

Codaster  M'Coy  (Codonaster  Koemer;  Heteroschisma  WsLchsm.)  (Fig.  260). 
Calyx  inverted,  conical  or  pyramidal.  Upper  face  broad,  truncate  or  gently 
convex ;  section,  as  a  rule,  distinctly  pentagonal.  Basais  forming  a  conical  or 
triangulär  cup,  usually  deep.  Kadials  large,  their  limbs  bent  inward  horizon- 
tally,  to  assist  in  forming  the  truncated  upper  face  of  the  calyx,  and  never 
deeply  excavated  by  the  sinuses.  Deltoids  wholly  confined  to  the  upper  face, 
as  are  also  the  amhulacra.  The  latter  are  petaloid,  or  narrow  and  linear  ; 
lancet-plate,  as  a  rule,  deeply  excavated  for  the  side-plates.     Spiracles  absent, 


Fig.  2Ü0. 

Codaster  acutus  M'Coy.  Lower  Carbonifer- 
ous ;  Derbyshire.  A,  Side-view  of  calyx.  B, 
Base.  C,  Ventral  aspect,  enlarged  (after 
Roemer). 


Fig.  261. 

Oropliocrinus  stelliformis  (O.  and  S.).  Lower 
Carboniferous  ;  Burlington,  Iowa.  A,  Calyx  and 
base  of  the  natural  size.  B,  Ventral  surface  en- 
larged (after  Meek  and  Worthen). 


hydrospires  pendent,  arranged  in  eight  groups,  two  in  each  of  the  four 
regulär  interrays,  but  wanting  in  the  anal  one.  The  tubes  open  externally 
by  a  variable  number  of  elongated  slits,  which  are  separated  by  intervening 
ridges ;  one  or  more  of  them  may  be  partially  concealed  by  the  overlapping 
side-plates.  Anus  large,  ovate  or  rhombic,  and  piercing  the  posterior  deltoid. 
Ornament  consisting  of  fine  lines  arranged  parallel  to  the  margins  of  the 
plates.     Silurian  to  Lower  Carboniferous;  Europe  and  North  America. 

Fhaenoschisma  E.  and  C.  (Fig.  254,  B).  Calyx  resembling  that  of  Codaster 
in  general  form,  but  with  ten  groups  of  hydrospires  instead  of  eight.  Radiais 
bear  each  three  more  or  less  distinct  folds  diverging  from  the  lip;  sinuses 
wide  and  deep,  generally  with  steep  sides.  Deltoids  small,  confined  to  the 
truncated  upper  face  of  the  calyx.  Lancet-plates  in  all  but  one  species 
(P.  caryophyllatum)  concealed  by  the  side-plates ;  outer  side-plates  very  small. 
Spiracles  rarely  present.  Hydrospires  pendent,  and  opening  externally  by  a 
series  of  elongate  slits  with  intervening  ridges,  distributed  in  sub-parallel 
Order  on  the  sloping  sides  of  all  the  radial  sinuses.  The  slits  are  only 
partially  covered  by  the  ambulacral  plates,  and  are  sometimes  visible  for  their 
entire  length.  Lower  Devonian  ;  Spain.  Lower  Carboniferous  ;  Europe  and 
North  America. 


CLASS  II 


BLASTOIt)EA 


169 


Cryptoschisma  E,  and  C.  Calyx  elongated,  with  a  broad,  fiat,  truncated 
Upper  face.  Radial  siiiuses  wide  and  open,  their  sloping  sides  pierced  by 
hydrospire  slits,  which  are  completely  concealed  by  broad,  petaloid  ambulacra. 
Spiracles  small,  single  or  more  rarely  double  ;  in  the  latter  case  the  posterior 
pair  are  confluent  with  the  anus.  Represented  by  the  solitary  species  C. 
schultzi  d'Archiac  and  de  Vern.     Lower  Devonian  ;  Spain, 

Orophocrinus  v.  Seebach  {Dimorphocrinus  d'Orb. ;  Codonites  M.  and  W.), 
(Figs.  258  I),  261).  Calyx  balloon-shaped  to  truncate  ob-pyramidal,  with 
more  or  less  concave  upper  face.  Section  distinctly  pentagonal  or  stellate. 
Ambulacra  narrow,  linear  to  sub-petaloid.  Deltoids  generally  visible  in  side- 
view,  the  posterior  one  wider  than  the  others.  Spiracles  ten,  varying  from 
wide  clefts  along  the  sides  of  the  ambulacra  to  narrow  slits  at  their  upper 
ends  ;  the  posterior  pair  separate  from  the  anus.  Hydrospire-slits  almost 
completely  concealed,  being  concentrated  at  the  bottom  of  the  radial  sinuses. 
Stem  round,  composed  of  short,  nearly  equal  joints.  Pinnules  extending  to 
nearly  twice  the  height  of  the  calyx,  of  uniform  thickness  throughout,  and 
composed  gf  sharply  cuneate  pieces  interlocking  from  opposite  sides ;  ventral 
furrow  wide,  and  covered  by  small  pieces.  Lower  Carboniferous ;  Britain, 
Belgium  and  North  America  (Kinderhook  and  Burlington  Groups). 


Family  2.     Pentremitidae    d'Orbigny. 

Base  usually  convex,  and  often  much  elongated.  Spiracles  five,  hut  sometimes  more 
or  less  completely  divided  by  a  median  septum,  and  bounded  proximally  by  the  upper- 
most  side-plates.  Lancet-plate  either  entirely  visible  or  partially  covered  by  side-plates 
which  extend  to  the  margins  of  the  ambulacra. 
Hydrospires  concentrated  at  the  lowest  part  of  the 
radial  sinus.  Devonian  and  Lower  Carbon- 
iferous. 

Fentremites  Say  (Figs.  254-7,  262-3). 
Calyx  usually  ovate  or  pyriform,  with  elon- 
gate,  sub-truncate  base.  Ambulacra  broad, 
sub-petaloid.  Lancet-plate  wholly  exposed, 
and  resting  below  on  an  under  lancet-plate. 
Side-plates  and  outer  side-plates  numerous, 
the  former  abutting  against  the  edges  of  the 
lancet-plates.  Hydrospires  three  to  nine; 
spiracles  single,  or  occasionally  double  ;  the 
two  of  the  posterior  side  confluent  with  the 
anus,  and  forming  with  it  a  single  large 
orifice.  Oral  centre  surmounted  by  numerous 
spines,  placed  closely  against  one  another  so 
as  to  form  a  pyramid,  which  completely  Covers 
the  summit  and  the  greater  portion  of  the   Lower  Carbon 

•      1        1         1  •        1      T  iferous  ;       III 

spiracles.    Lxcessively  abundant  m  the  Lower  (Nat  size). 
Carboniferous  of  North  America  (Burlington 
to  St.  Louis  and  Kaskaskia  Groups),  but  not  identified  in  Europe 
Defrance,  and  P.  pyriformis  Say,  are  the  most  familiär  species. 

Pentremitidea  d'Orb.       Calyx    clavate-pyramidal,   with    elongate,    usually 
conical  base,  and   truncate  or  convex  upper  face.     Aml)ulacra  narrow,  short ; 


■  Fig.  2C2. 

Pentremites 
(jodoni       Defr. 


Fio,  263. 

Pentremites  svlcatus 
Lower  Carbon- 
iferous;  111.;  A,  Summit 
aspect.    B,  base. 


Roemer. 


P.  godoni 


170 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


lancet-plate  more  or  less  completely  concealed  by  side-plates.  Deltoids  very 
small,  generally  confined  to  the  upper  face  of  the  calyx,  and  seldom  visible  in 
a  side-view.  Spiracles  and  hydrospires  as  in  the  preceding.  Lower  and 
Middle  Devonian  ;  Eifel,  Ardennes,  Spain,  Great  Britain  and  North  America 
(Hamilton  Group  of  Indiana,  Michigan,  Canada).  P.  pailletti  de  Vern.;  F. 
eifelianus  Roemer ;  F.  davatus  Schnitze. 


Family  3.      Troostoblastidae    Etheridge  and  Carpenter. 

Calyx  elongate.     Ambulacra  narrow,  linear,  deeply  impressed,  descending  out- 
ward from  the  summit.     Deltoids  confined  to  the  narrow  upper  end,  rarely  visible 
A  externally,  except  the  posterior  one  in  Troostocrinus.     Lancet- 

plate  entirely  concealed  by  side-plates.  Spiracles  distinct,  repre- 
sented  by  lineal  slits  at  the  sides  of  the  deltoid  ridge,  and 
bounded  by  deltoids  and  lancet-plates,  but  not  by  side-plates. 
Silurian  to  Lower  Carboniferous. 

Troostocrinus  Shum.  (Clavaeblastus  Hambach)  (Fig. 
264).  Calyx  narrow,  elongate,  somewhat  fusiform,  with 
contracted,  subtruncate,  or  slightly  convex  upper  face. 
Ambulacra  short.  The  four  anterior  deltoids  overlapped 
by  the  radial  limbs ;  the  posterior  one  much  larger  than 
the  rest,  and  appearing  externally.  Posterior  spiracles 
conflueht  with  the  anus.  Silurian  (Niagara  Group) ; 
North  America. 

Metablastus  E.  and  C.  (Fig.  258,  C).  Like  the  preced- 
ing, but  all  the  deltoids  equal,  and  the  two  posterior 
spiracles  not  confluent  with  the  anus.  Spiracle  slits  ten 
in  number ;  hydrospires  four  to  each  side  of  an  am- 
bulacrum.  Devonian  to  Lower  Carboniferous  (Keokuk 
Group) ;  Europe  and  North  America. 

Tricoelocrinus  M.  and  W.  (Saccoblastus  Hambach).    Calyx 


ir  an+sp 

Fig.  264. 


Troostocrinus  reinwarm    pyramidal,  broadest  below  and  narrowing  upwards  ;  when 


(Troost).     Silurian 

nessee.^, Calyx  from  anal    ggen  from  abovc  or  below  stroudv  pentaeronal  in  outline, 

side.     B,  Snmmit  aspect.  .  ..  i.ii  r      ^ 

(Z,  Deltoid ;  ir,  Deltoid  of    owing  to  the  projectmg  and  carinated   character  oi   the 

anal  side  (after  E.  and  C).  j-i  t\   ii.    -j  n  i,i 

radials.  Deltoids  small  ;  ambulacra 
long,  and  extremely  narrow.  Spiracles  ten,  distinct ;  anus 
large.  Hydrospires  small,  enclosed  within  the  substance  of 
the  forked  plates.  Lower  Carboniferous  (Warsaw  Group) ; 
North  America. 


Family  4.     Eleutherocrinidae   Bather. 

Elongate,  stemless,  asymmetrical,  with  four  narrow  ambulacra  ; 
fifth  ambulacrum  shortened  and  widened.  Hydrospires  not  con- 
centrated.     Devonian. 

Eleutherocrinus  Shumard  and  Yandell  (Fig.  265). 
Devonian  (Hamilton  Group) ;  Indiana,  Kentucky,  New  York  and  Canada 


Fk;.  'Mb. 
Eleutherocrinus  casse- 
dnyi  (Shum.  and  Yand.). 
Lower  Devonian  ;  Ky. 
Ventral  surface,  -/i 
(after  E.  and  C). 


Family  5.     Nucleocrinidae    Bather. 

Calyx  usually  globular  or  ovoidal,  with  flattened  or  concave  base,  and  linear 
ambulacra  extending  the  whole  length  of  the  calyx.     Spiracles  distinctly  double,  and 


CLASS  II 


BLASTOIDEA 


171 


chiefly  formed  hy  the  apposition  of  notches  in  the  lancet-plate  and  deltoids.  Devonian 
and  Carboniferous. 

Nucleocrinus  Conrad  {Elaeacrinus  Koeiner ;  Olivanites  Troost)  (Fig.  266). 
Basais  small,  inconspicuous,  sometimes  hidden  within  the  columnar  cavity. 
Radiais  small,  with  very  short  limbs.  Deltoids 
greatly  enlarged  and  elongated,  forming  over 
two-thirds  of  the  entire  calyx ;  the  posterior  one 
wider  than  the  others,  and  divided  by  a  large 
anal-plate.  Lancet-plate  exceedingly  long  and 
narrow,  partly  exposed.  Side-plates  numerous  ; 
hydrospires  two  on  each  side  of  the  ambulacra. 
Summit  covered  by  comparatively  large  orals, 
asymmetrically  arranged  and  forming  a  flattened 
disk  which  completely  closes  the  peristome. 
Devonian  (Onondaga  and  Hamilton  Groups) ; 
Indiana,  Michigan,  New  York. 

Schizoblastus  E.  and  C.  (CribroUastus  Ham- 
bach).  Calyx  resembling  that  of  Orhitremites  in 
form.  Basais  almost  always  confined  to  the 
lower  face  of   the  calyx  ;    deltoids    of    variable 

Size,  but  always  Visible    in    a    side-view.       Hydro-    Devonian ;  Columbus,  O.(afterRoemer). 
.  '  /  ^     y     ^         A,  Side-view  of   calyx.     B,  Base.     C, 

Spn*es  one  to  four  to  each  ambulacrum.      bpiracles    ventral  surface.     D,  Same  enlarged. 

small,  slit-like,  placed  between  the  lancet-plates 

and  deltoid  ridges ;  the  posterior  pair  sometimes  confluent  with  the  anus. 
Lower  Carboniferous ;  Ireland  and  North  America  (Kinderhook  to  Keokuk 
Groups);  Permian,  Timor. 


Fio.  266. 
Nucleocrinus  verneuili  (Troost).  Lower 


Family  6.     Orbitremitidae   Bather. 

Calyx  globular  or  owidal,  with  flattened  or  concave  base,  and  long  linear 
ambulacra.  Spiracles  five,  piercing  the  deltoids,  or  ten,  grooving  their  lateral  edges. 
Lower  Carboniferous. 

Orhitremites  Austin  (Granatocrinus  Hall  ex  Troost  MS. ;  Cidaroblastus  and 
Globoblastus  Hambach)  (Figs.  263  J,  258  A).  Calyx  ovate  to  globose.  Lower 
face  from  slightly  concave  to  deeply  funnel-shaped  ;  interradial  areas  more  or 
less  depressed.  Basais  small,  generally  concealed  in  the  central  columnar 
cavity.  Radiais  very  variable  in  size,  often  long,  and  invariably  turned  in 
below  to  assist  in  forming  the  base.  Deltoids  also  variable  ;  usually  unequally 
rhombic,  but  sometimes  triangulär ;  the  anal  deltoid  f requently  difFering  from 
the  others.  Ambulacra  nearly  parallel-sided,  always  impressed  within  the 
sinuses  at  their  proximal  ends.  Lancet-plates  narrow,  not  Alling  the  sinuses, 
and  more  or  less  exposed  throughout  two-thirds  of  the  ambulacra.  Side-plates 
transversely  elongated ;  outer  side-plates  generally  well  developed.  Hydro- 
spires pendent,  usually  but  two  or  three  folds  on  each  side  of  an  ambulacrum ; 
the  inner  one  forming  a  well-defined  hydrospire-plate.  Spiracles  five,  piercing 
the  apices  of  the  deltoids.  Posterior  spiracle  larger,  including  the  anus. 
Summit  closed  by  minute  pieces  which  rarely  exhibit  any  definite  arrange- 
ment.  Lower  Carboniferous;  England  and  North  America  (Burlington 
Group),  (?)  Australia. 


172  ECHINODERMATA— PELMATOZOA  phylum  iv 

Cryptohlastus  E.  and  C.  Calyx  sub-globose,  with  a  flatteried  or  slightly 
hollowed  base.  Basais  and  deltoids  small.  Lancet-plate  separated  from  the 
radials  by  a  hydrospire-plate,  which  does  not  extend  above  the  radio-deltoid 
suture ;  but  above  this  line  the  lancet-plate  meets  the  deltoids  without  leaving 
any  hydrospire-pores.  Spiracles  round,  distinctly  double  at  four  of  the  sides, 
but  those  of  the  posterior  side  confluent  with  each  other  and  with  the  anus. 
Summit  covered  by  numerous,  irregularly  arranged  small  pieces.  Lower 
Carboniferous  (Burlington  Group) ;  North  America. 

HeteroUastus  E.  and  C.  Eesembling  the  preceding  in  form  and  proportion 
of  its  component  parts.  The  proximal  ends  of  the  deltoids  produced  in  short 
spine-like  processes,  at  the  base  of  which  minute  lateral  openings,  one  to  each 
deltoid,  are  visible.  These  openings  lead  into  gutter-like  Channels  excavated 
in  the  substance  of  the  plates  for  the  reception  of  the  proximal  ends  of  the 
two  hydroBpire-canals.  Eadial  sinuses  wide,  their  edges  sloping  gently 
downwards  to  the  slightly  petaloid  ambulacra.  Lower  Carboniferous ; 
England  and  (?)  North  America. 

Mesoblastus  E.  and  C.  Calyx  ovoid  to  globose,  with  concave  to  protuberant 
base.  Eadials  long,  deltoids  small,  short,  unequally  rhombic.  Ambulacra 
very  narrow,  extending  to  the  base.  Spiracles,  as  a  rule,  distinctly  double, 
but  sometimes  incompletely  divided.  Lancet-plate  entirely,  or  for  the  most 
part,  concealed  by  side-plates.  Lower  Carboniferous ;  Belgium,  England, 
(?)  North  America  and  Australia. 

Acentrotremites  E.  and  C.  Calyx  elliptical,  with  broad  pentagonal  lower 
face.  Radials  large,  taking  up  three-fourths  of  the  height  of  the  calyx. 
Deltoids  unequally  rhombic,  each  notched  by  two  spiracles  at  the  ends  of  the 
radio-deltoid  suture.  Anal  opening  situated  close  to  the  summit  in  the 
posterior  deltoid.  Ambulacral  edges  of  the  deltoids  without  hydrospire-pores. 
Lower  Carboniferous  ;  England.  ' 

CarpenteroUastus  and  Lophoblastus  Rowley.  Lower  Carboniferous  (Kinder- 
hook and  Burlington  Croups) ;  North  America. 

(?)  NymphaeoUastus  von  Beetz.     Lower  Carboniferous  ;  Russia. 

Family  7.     Pentephyllidae    Bather. 

Calyx  stemless  and  sub-pentagonal ;  radials  asymmetrical.  Ambulacra  linear, 
extending  dotun  to  the  base  ;  one  shorter  than  the  rest.     Carboniferous. 

Pentephyllum  Haughton.     Carboniferous ;  Ireland. 

Family  8.     Zygocrinidae   Bather. 

Stemless.  Calyx  depressed,  asymmetrical,  quadrilobate.  Four  ambulacra 
between  the  lobes,  accompanied  by  a  single  hydrospire  on  either  side  ;  fifth  ambulacrum 
shortened  and  widened. 

Zygocrinus  Bronn  (Astrocrinus  Austin,  non  Conrad  nee  Münster).  Lower 
Carboniferous ;  Great  Britain. 

[The  text  for  the  group  Blastoidea  in  the  present  work  has  been  revised  by  Mr.  Frank 
Springer,  of  Las  Vegas,  New  Mexico,  and  Washington,  D.C.— Epttor,] 


CLAss  III  CRINOIDEA  173 

Olass  3.    ORINOIDEA  Miller.    Sea-lilies. ' 
(Brachiata  Bronn  ;  Adinoidea  F.  Roemer.) 

Usaally  long-stalked,  more  rarely  non-pedunculate  and  sessile,  frequently  free- 
swimming  Pelmatozoa,  with  calyx  composed  of  regularly  arranged  plates,  and  provided 
with  well-developed  movahle  arms. 

The  Crinoid  organism  consists  of  three  principal  elements — calyx,  arms 
and  stalk.  The  calyx  and  arms  together  are  sometimes  spoken  of  as  the 
crown,  as  contrasted  with  the  column  (also  called  stem  or  stalk). 

1.  The  Calyx. — The  calyx  has  usually  the  form  of  a  cup-shaped,  bowl- 
shaped,  or  globular  capsule,  within  which  the  more  important  organs  are 
enclosed.  Its  lower  (dorsal  or  abactinal)  surface  commonly  rests  upon  a 
column  (Fig.  267) ;  but  in  some  forms  it  is  attached  directly  by  the  base, 
and  in  rare  instances  it  is  free.  The  superior  (ventral  or  actinal)  surface  is 
either  membranous  or  plated ;  it  carries  the  mouth  and  ambulacral  grooves, 
and  hence  is  homologous  with  the  under  side  of  a  star-fish  or  sea-urchin.  As 
a  rule,  only  the  inferior  and  lateral  portions  (dorsal  cup)  of  the  calyx  are 
visible,  owing  to  the  concealment  of  the  summit  by  the  arms.  The  cup 
is  constituted  of  two  or  more  circlets  of  plates,  which  are  uniformly  oriented 
with  reference  to  the  ambulacral  organs. 

a.  By  the  hase  is  understood  the  one  or  two  circlets  of  plates  intervening 
between  the  topmost  Joint  of  the  column  and  the  first  cycle  of  radially  situated 

1  Literatnre  :  Miller,  J.  <S.,  A  Natural  History  of  the  Crinoidea  or  lily-shaped  Animals,  1821. — 
Müller,  J.,  Ueber  den  Bau  des  Pentacrinus  caput-medusae.  Abhandl.  Akad.  Wiss.  Berlin,  1841. 
— de  Koninck,  L.  G.,  et  le  Hon.  H.,  Recherches  sur  les  crinoides  du  terrain  carbonifere  de  la  Bel- 
gique.  Brüssels,  1854.  (Very  extensive  bibliography.) — Beyrich,  E.,  Die  Crinoideen  des  Muschel- 
kalks. Abhandl.  Akad.  Wiss.  Berlin,  1857. — Schnitze,  L.,  Monographie  der  Echinodermen  des 
Eifler  Kalks.  Denkschrift  Akad.  Wiss.,  1867,  vol.  xxvi. — Shumard,  B.  F.,  Catalogue  of  Palaeozoic 
Echinodermata  of  North  America.  Trans.  St.  Louis  Acad.  Sei.,  1868,  vol.  ii.  (Very  complete 
bibliography.) — Carpenter,  W.  B.,  On  the  Structure,  Physiology,  and  Development  of  Antedon 
rosaceus.  Philos.  Trans.,  1876,  vol.  elvi. —  Wachsmuth,  C,  and  Springer,  F.,  Revision  of  the  Palaeo- 
erinoidea.  I.-III.  Proc.  Acad.  Nat.  Sei.  Philad.,  1879-86. — Idem,  Discovery  of  the  Ventral  Struc- 
ture of  Taxocrinus  and  Haplocrinns,  ibid.,  1888. — Idem,  The  Perisomic  Plates  of  Crinoids,  ibid.,  1890. 
— Idem,  The  Crinoidea  Camerata  of  North  America.  Mem,  Mus.  Comp.  Zool.,1897,  vols.  xx.,  xxi. 
— Loriol,  P.  de,  Paleontologie  Fran9aise.  Crinoides  Jurassiques,  I.-II.,  1882-89. — Neumayr,  M., 
Die  Stämme  des  Tierreichs,  1889. — Agassiz,  A.,  Calamocrinus  Diomedae.  Memoirs  Museum  Comp. 
Zool.  1892,  vol.  xvii. — Bather,  F.  A.,  British  Fossil  Crinoids.  Ann.  and  Mag.  Nat.  Hist.,  1890-92, 
ser,  6,  vols.  v.-ix. — Idem,  The  Crinoidea  of  Gotland.  K.  Svenska  Vetensk.  Akad.  Handlingar, 
1893,  vol.  XXV. — Idem,  A  Treatise  on  Zoology  (Lankester)  pt.  iii.,  Echinoderma,  1900. — Jaekel, 
0.,  Crinoiden  Deutschlands.  Pal.  Abhandl.  Jena,  neue  Folge,  1895,  vol.  iii. — Springer,  F.,  Uinta- 
crinus,  its  structure  and  relations.  Mem.  Mus.  Comp.  Zool.,  1901,  vol.  xxv.,  No.  1. — Jdem,  Cleio- 
crinus.  Mem.  Mus.  Comp.  Zool.,  1905,  vol.  xxv.,  No.  2. — Idem,  Discovery  of  the  disk  of 
Ouychocrinus.  Journ.  Geol.,  1906,  vol.  xiv. — Idem,  A  Trenton  Echinoderm  Fauna.  Geol.  Surv. 
Canada,  1911,  Memoir  No.  15,  P. — Idem,  New  American  Fossil  Crinoids.  Mem.  Mus.  Comp.  Zool., 
1911,  vol.  xxv.,  No.  3. — Ide7)i,  The  Crinoidea  Flexibilia.  (Monograph  in  preparation. ) — Chad- 
wick, II.  C,  Antedon.  Liverpool  Marine  Biol.  Comm.,  1907,  Mem.  15. — Clark,  A.  H.,  Variouf«  im- 
portant papers  on  recent  and  fossil  Crinoids  in  Proc.  U.S.  Nat.  Mus.,  1908-11,  vols.  xxxiv.-xl. — 
Idem,  On  a  collection  of  Crinoids  from  the  Zoological  Museum  of  Copenhagen.  Vidensk.  Medd. 
fra  den  Naturhist.  Forening  i,  K0benhavn,  1909. — The  probable  origin  of  the  Crinoid al  nervous 
System.  Amer.  Nat.  1910,  vol.  xliv. — Remarks  on  the  nervous  System  and  symmetry  of  the 
Crinoids.  Journ.  Wash.  Acad.  Sei.,  1911,  vol.  i. — The  Recent  Crinoids  of  Australia.  Memoir  4, 
Australian  Museum,  Sydney,  N.S.W.,  1911.— The  Crinoids  of  the  Indian  Ocean.  Memoir  of  the 
Indian  Museum,  Calcutta.  (In  press.) — The  Existing  Crinoids.  Special  Bulletin,  U.S.  National 
Museum.  (In  press.) — Wood,  E.,  A  critical  suminary  of  Troost's  unpublished  manuscript  on  the 
Crinoids  of  Tennessee.  Bull.  U.S.  Nat.  Mus.,  1909,  No.  64. — Kirk,  E.,  Structure  and  relationships 
of  certain  Eleutherozoic  Pelmatozoa.     Proc.  U.S.  Nat.  Mus.,  1911,  vol.  xli. 


174 


ECHINODEKMATA— PELMATOZOA 


PHYLUM  IV 


plates  at  the  base  of  the  ambulacra  or  arms.      When  the  base  is  monocyclic 
(Fig.  268)  the  position  of  the  proximal  ring  of  plates  is  interradial ;  but  when 


Fig.  267. 

Euspirocrinus  spir- 
alis  Ang,  Stalked 
Crinoid  with  dicyclic 
base  and  anal  inter- 
radius.  a,  Anals ;  b, 
Basais;  ib,  Infrabasals; 
r,  Radiais.  (Right  and 
left  sides  reversed, 
after  Angelin.) 


Fig.  268. 

Cactocrinus  'probosckiialis  (Hall).  Prqjec- 
tion  of  calyx  sliowing  the  tliree  basals  (5), 
5x3  simple  radials  (r),  four  iiaired  interrays 
(ir),  and  a  tifth  unpaired  anal  interray  (a). 


Fig.  26'.). 

Pachylocrinus  multiplex 
(Traut).  Calyx  with  dicy- 
clic base,  radials,  costals, 
and  distichals. 


dicyclic  it  is  radial,  and  the  upper  ring  corresponds  with  the  basals  of  mono- 
cyclic forms  (Fig.  269). 

In  the  nomenclature  of  P.  Herbert  Carpenter,  the  upper  series  of  plates  in 
the  dicyclic  base  are  properly  termed  basals,  and  the  lower  series  infrabasals 
iunderbasals).      The  basals  as  thus  defined  are  equivalent  to  the  "parabasals" 

in  the  older  nomenclature  of  Johannes  Müller, 
and  to  the  "  subradials "  of  de  Koninck  and 
other  authors. 

Both  basals  and  infrabasals  are  primarily  five 
in  number ;  but  owing  to  the  supposed  morpho- 
logical  (rarely  if  ever  actual  physical)  fusion  of 
two  or  more  of  the  plates,  the  number  of  basals 
in  the  monocyclic  forms  may  be  reduced  to  four, 
three,  two,  or  even  to  a  single  undivided  plate ; 
and  that  of  infrabasals  in  the  dicyclic  to  three. 
During  the  ontogenetic  developmentof  the  Recent 
Antedon,  a  more  or  less  complete  resorption  of  the 
basals  has  been  observed,  which  ultimately  results 
in  their  passage  from  the  dorsal  to  the  ventral 
side  of  the  so-called  chambered  organ,  where  they 
are  again  rebuilt,  becoming  a  curious  plate-like  structure  known  as  the 
rosette;  and  the  same  probably  also  was  true  for  certain  Mesozoic  genera 
(Eugeniacrinus,  Phyllocrinus).  In  many  of  the  non-pedunculate  Crinoids 
{Uintacrinus,  Marsupites,  Fig.  270)  an  additional  plate  known  as  the  centrale 
rests  against  the  infrabasals,  and  probably  represents  an  undeveloped  stalk. 
The  bg,sals  are  united  with  one  another  and  with  the  overlying  radials  by 


Fig.  270. 

Marsupites  testudinaris  (Schloth.). 
Diagram  of  calyx.  cd,  Centrale ;  ib, 
Infrabasals  ;  b,  Basals ;  r,  Radials. 


3LASS  III  CRINOIDEA  175 

ery  numerous  short  fibres  of  connective  tissue,  which  may  become  more  or 
ess  calcified ;  this  forms  an  immovable  Union  of  the  type  known  as  a  close 
uture,  in   which   the  plates  are  immovably   held  together  by  fibrous  con- 

ective  tissue.  Though  usually  smooth,  the  Joint  faces  are  sometimes 
triated,  which  striations  are  visible  externally  as  incised  lines. 

b.  Succeeding  the  base  is  a  cycle  of  five  (rarely  four,  six,  or  ten)  plates, 
which,  on  account  of  their  position  with  reference  to  the  rays,  are  called 
radials.  The  radials  form  the  sides  (more  rarely  the  floor)  of  the  calyx 
in  nearly  all  Mesozoic  and  Recent  Crinoids,  and  give  origin  directly  to 
the  arms,  which  may  become  free  immediately  above  the  radials,  or  may  be 
incorporated  for  some  distance  in  the  calyx,  either  by  means  of  supplementary 
plates,  or  by  lateral  union  among  themselves. 

The  Upper  boundary  of  the  calyx  is  differently  demarcated  by  dilFerent 
authors.  Many  assign  all  the  plates  above  the  first  cycle  of  plates  in  each 
ray  to  the  arms,  even  when  they  are  immovably  united  with  one  another  at 
the  sides ;  while,  according  to  Schultze  and  others,  the  arms  begin  invariably 
at  the  point  where  they  first  became  movable,  i.e.  above  the  first  articular 
facet.  The  latter  course  is  open  to  serious  objections,  inasmuch  as  strictly 
homologous  parts  receive  different  appellations  in  different  groups. 

Carpenter,  Wachsmuth  and  Springer,  and  Bather  restrict  the  term  "  radial  " 
to  the  lowermost  circlet  of  radially  situated  plates,  and  consider  the  succeed- 
ing cycles  as  far  as  and  including  the  first  axiliary  plate  as  hrachials  (dis- 
tinguished  as  first,  second,  and  third  costals,  distichals,  and  palmars ;  or  as 
first,  second  and  third  primibrachs  (IBr),  secundibrachs  (IIBr),  and  terti- 
brachs  (IIIBr)  respectively),  in  all  cases,  whether  the  plates  are  free  or 
fixed. 

In  most  Paleozoic  Crinoids  one  or  more  interradial  plates  are  intercalated 
between  two  of  the  rays,  and  in  line  with  the  anal  aperture  ;  these  are  called 
the  anal  plates  or  anals.  If  a  plane  be  passed  through  the  latter  and  through 
the  radial  situated  directly  opposite,  the  calyx  will  be  divided  into  two 
symmetrical  halves  :  the  parts  lying  to  the  right  or  left  when  viewed  from  the 
posterior  or  anal  side  are  so  designated ;  while  the  anterior  side  is  that  oppo- 
site the  anal  interray.  Interradial  plates,  however,  are  not  confined  to  the 
anal  interray,  but  are  frequently  developed  also  between  the  other  rays,  when 
the  calyx  is  correspondingly  expanded.  If  several  cycles  of  radials  and 
brachials  are  present,  an  equal  number  of  interradials  may  be  developed,  and 
are  distinguished  in  like  manner  as  interradials  and  distichal  interradials  of 
various  Orders.  The  anal  interray  is  frequently  characterised  by  the  peculiar 
number,  size  and  position  of  the  anal  plates. 

c.  The  superior  side  of  the  calyx  is  known  as  the  tegmen  calycis.  The 
covering  may  be  in  the  form  of  a  coriaceous  skin,  in  which  large  numbers  of 
thin  calcareous  ossicles  are  embedded  (Figs.  271,  272),  or  of  a  plated  disk 
rising  from  the  base  of  the  arms.  It  frequently  exhibits  a  more  or  less 
central,  externally  visible  mouth-opening,  and  a  usually  eccentric  interradial 
anal  aperture.  The  mouth  opens  into  an  Oesophagus  and  thence  into  the  ex- 
panded visceral  mass,  which  fills  the  greater  portion  of  the  inner  cavity.  The 
intestinal  canal  is  directed  downwards  at  first,  and  after  making  usually  one 
complete  circle,  more  rarely  after  numerous  windings,  discharges  into  the 
anal  opening.  In  certain  fossil  Crinoids  (Actinocrinidae)  the  digestive  appara- 
tus  is  represented  by  an  extremely  thin-walled,  finely  perforated,  convoluted 


176 


ECHINODERMATA—PELMATOZOA 


PHYLUM  IV 


calcified  body,  wliich  occupied  the  vertical  axis  of  the  body  cavity,  and  was 
contracted  into  a  narrow  tube  toward  the  base  (Fig.  280). 

In  all  of  the  Recent  Crinoids  (excepting  in  certain  species  belonging  to  the 
family  Comasteridae  where  they  may  be  quite  absent  from  the  arms  arising  from 
one,  two,  or  even  three  of  the  posterior  rays)  each  arm,  and  each  pinnule 
which  it  bears,  carries  on  its  ventral  surface  an  open  ambulacral  furrow  lined 
with  ciliated  epithelium.  At  the  base  of  the  arms  these  ambulacral  furrows 
unite  and  form  five  large  furrows,  which,  traversing  the  tegmen,  converge  at 
the  central  mouth,  or,  as  in  the  Comasteridae,  lead  to  a  horse-shoe  shaped 
furrow  just  within  the  border  of  the  tegmen  in  the  centre  of  which  is  the 
mouth.  Just  below  the  floor  of  these  furrows  runs  a  nerve  band  (absent  from 
ungrooved  arms),  and  under  this  the  genital  rachis  (especially  developed  in 
ungrooved  arms),  and  the  canals  of  the  water  and  blood  vascular  Systems  ; 
below  these,  deeply  buried  within  the  substance  of  the  calcareous  plates,  lies 
the  large  nerve  cord  of  the  dorsal  nervous  System.  All  but  the  last  of  these, 
which  leads  to  a  central  nervous  mass  in  the  dorsal  apex  of  the  calyx,  run  to 


Isocrinus  asteria  (Linii.).  Ventral 
disk,  protected  by  very  thin  peri- 
somic  plates,  witli  central  mouth  (o), 
exposed  anibulacra,  and  eccentric 
anus  (A). 


Hyocrinus  hethelianus  (Wyv.  Thoin.).  Re- 
cent. Ventral  disk,  enlarged.  o,  Orals  ;  p, 
Mouth  (peristome) ;  s,  Covering  plates ;  c, 
Dorsal  canals  of  the  anus ;  a?u,  Ambulacral 
furrows  of  the  arms  ;  a»,  Anus  (after  Wyville 
Thomson). 


ring-like  structures  surrounding  the  Oesophagus.  The  circumoesophageal  ring 
canal  of  the  water  vascular  System  is  in  communication  with  the  body  cavity, 
which  in  turn  communicates  with  the  exterior  by  means  of  very  numerous 
(five  only  in  Ehizocrinus)  interradial  perforations.  The  margins  of  the 
ambulacral  grooves  are  bordered  with  a  series  of  small  lappets,  and  at  the 
base  of  each  of  these  is  a  group  of  three  tentacles  ;  these  tentacles,  which  are 
absent  from  ungrooved  arms,  are  connected  with  the  canal  of  the  water 
vascular  system  ;  they  also  secrete  a  more  or  less  poisonous  fluid  which  serves 
to  paralyze  the  small  organisms  which  serve  as  food. 

In  all  Recent  Crinoids  five  (occasionally  four)  open  ambulacral  furrows 
lined  with  epithelium  conduct  from  the  mouth  to  the  tips  of  the  arms, 
remaining  either  simple  or  subdividing  as  often  as  there  are  arms.  Under- 
neath  the  floor  of  the  grooves  runs  an  ambulacral  vessel  filled  with  water ; 
and  accompanying  this  are  the  blood  and  vascular  canals  and  a  nervous  cord. 
Distensible  tentacles  pass  out  from  alternate  sides  of  the  ambulacra,  and  the 
latter  unite  to  form  a  circumoral  ring  canal  From  the  ring  canal  five  short 
open  tubes  (stone  or  water  canals)  extend  downwards  into  the  body  cavity  and 
supply  the  ambulacral  system  with  water. 


CLASS  III 


CRINOIDEA 


177 


In  certain  of  the  Recent  stulked  genera,  as  in  Hyocrinus  (Fig.  272),  in 
the  young  of  all  the  Recent  species,  and  in  a  large  number  of  fossil  Crinoids, 
a  triangulär  oral  plate  is  situated  at  each  of  the  five  angles  of  the  mouth-open- 
ing.  The  apices  of  the  orals  are  directed  towards  one  another,  and  between 
them  run  the  ambulacra.  Oral  plates  are  extremely  variable  in  size ;  and 
although  well-developed  in  the  larvae  of  the  Comatulids  and  in  the  young  of 
many  of  the  stalked  species,  they  become  wholly  resorbed  before  maturity. 
In  a  number  of  Paleozoic  Crinoids  (Fig.  275)  the  summit  is  entirely  or  in 
large  part  composed  of  five  oral  plates  which  may  be  either  laterally  in 
contact  or  separated  by  furrows.  More  frequently,  however,  the  orals  occupy 
only  the  angles  of  the  mouth-opening,  the  remaining  area  between  the 
ambulacral  furrows  being  covered  with  more  or  less  regularly  arranged 
interamhulacral  plates  (Fig.  272).  In  most  of  the  Paleozoic  Camerata,  and  in  all 
the  Recent  species,  the  anus  is  placed  at  the  upper  end  of  a  tube  known  as  the 


Fio.  273. 

Lecytliocrinus  eifeliatius 
Müller.  Crinoid  with  elon- 
gated  anal  tube  (alter 
Schnitze). 


Fig.  274. 

Dorycrlnus  quinquelohus  (Hall). 
Specimen  showing  plates  of  the  teg- 
nien  and  eccentric  anus. 


Fio.  275. 

Coccocrinus  rosaceus 
Roem.  Devonian  ; 
Bifel.  Calyx  with  ven- 
tral pavement.  X  2/, 
(after  Schnitze). 


anal  tube  or  proboscis.  In  the  Fistulata,  however,  the  anal  opening  is  situated 
along  the  anterior  side  of  the  ventral  sac,  or  between  the  sac  and'  the  mouth. 

Of  the  interamhulacral  plates  a  greater  or  smaller  number  (in  Calamocrinus 
all  in  the  vicinity  of  the  mouth)  are  perforated  by  pores  for  the  admission 
of  water  into  the  body  cavity.  Pores  evidently  performing  a  respiratory 
function  occur  in  some  of  the  Fistulata ;  but  these,  instead  of  piercing  the 
body  of  the  plates,  enter  only  their  outer  angles.  Other  Fistulata  have  a 
madreporite. 

The  ambulacra  are  frequently  lined  along  their  sides  by  more  or  less 
rounded  covering  plates  which  are  capable  of  being  folded  down  over  them 
so  as  to  serve  as  a  protection  ;  these  covering  plates  are,  at  least  in  the 
Recent  forms,  perisomic  plates  developed  in  the  marginal  ambulacral  lappets  ; 
they  may  occur  alone,  as  in  the  genera  Ehizocrinus,  N'emasier,  etc.,  but  they  are 
usually  separated  from  the  pinnulars  or  brachials  by  a  second  series  of  squarish 
or  oblong  plates  known  as  the  side  plates.  Both  series  of  plates  occur  every- 
where  along  the  ambulacral  grooves,  but  they  become  irregulär  and  ill-defined 
011  the  disk.  In  the  Paleozoic  Taxocrinus  (Fig.  276),  the  covering  pieces  are 
VOL.  I  N 


178 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


arranged  in  alternate  rows,  with  side-pieces  adjoining  them.  The  latter  plates 
occur  also  in  most  of  the  Inadunata  and  Flexibilia,  but  are  rarely  represented 
in  the  Camerata.  The  mouth  may  be  exposed  or  closed ;  either  being 
surrounded  by  five  oral  plates  {Taxocrinus,  Fig.  276),  or  the  posterior  oral  may 
be  pushed  in  between  the  four  others,  so  as  to  conceal  the  mouth ;  the  latter 
is  then  said  to  be  suUegminal  (Fig.  277). 

A  very  remarkable  modification  of  the  ventral  disk  occurs  in  the  Paleozoic 
Camerata.  Here  the  usually  very  numerous  plates  attain  considerable  thickness, 
and  fit  into  one  another  like  the  stones  of  an  arch  to  form  an  extremely  rigid, 
more  or  less  convex  vault,  which  is  sometimes  surmounted  by  an  equally  rigid 
plated  proboscis.  At  the  apex  of  the  dome  five  large-sized  plates  are  often 
distinguishable,  of  which  that  lying  in  the  anal  interradius  commonly  difFers 
from  the  rest  in  form  and  size,  and  appears  to  be  wedged  in  amongst  the  others. 
These  five  plates  are  identified  by  Wachsmuth  and  Springer  as  orals.  The 
remainder  of  the  tegminal  plates  are  distinguished  according  to  their  position  as 
ambulacrals  and  interambulacrals  ;  in  most  of  the  Batocrinidae  the  ambulacrals 


Fig.  276. 

Taxocrinus  intermed- 
ius  W.  and  Sp.  Ventral 
disk  (after  Wachsmuth 
and  Springer). 


Fig.  277. 

Platycrinus  Jialli  Shum.  Projection 
of  ventral  disk.  a,  Ambulacrals ;  ia,  In- 
terambulacral  areas  ;  ia',  Anal  inter- 
radius ;  e,  Covering  pieces  of  the  ambu- 
lacrals :  i,  Interradials  ;  jj,  Interior 
and  lateral  orals ;  o,  Posterior  (anally 
situated)  oral ;  x,  Plates  of  the  anal 
interambulacral  area  (after  W.  and  Sp.). 


Fig.  278. 

Hexacrinus  elongatus  Goldf.  Calyx 
with  tegmen.  ■  a,  Profile  ;  h,  Viewed 
from  above. 


are  not  arranged  in  alternate  rows  (Fig.  279),  but  frequently  consist  of 
large  single '  plates  '  of  one  or  more  Orders,  which  are  separated  from  one 
another  by  the  continuous  interposition  of  supplementary  pieces.  In  other 
groups,  notably  the  Platycrinidae,  the  ambulacrals  are  generally  arranged  in 
two  rows  of  rather  large  plates,  which,  however,  lose  their  original  character 
to  some  extent.  The  interambulacrals  usually  meet  with  the  interbrachials. 
The  tegmen  of  the  Camerata,  as  a  rule,  is  composed  of  large  convex  or  nodose 
plates,  for  the  Identification  of  which  considerable  experience  is  required. 

Most  of  the  Paleozoic  Crinoids  have  but  a  single  opening  in  the  tegmen, 
which  is  interradial  in  position,  or  sometimes  central,  and  represents  the  anus. 
With  the  exception  of  the  Flexibilia  the  mouth  is  subtegminal,  and  the  food 
grooves  are  rigidly  closed.  In  many  cases  the  covering  pieces  are  pushed 
inward,  and  the  ambulacra  follow  the  inner  floor  of  the  tegmen,  forming  a 
skeleton  of  ramifying  tubes ;  these  are  conducted  along  open  galleries  from 
the  mouth  to  the  arm-openings  (Fig.  280,  A). 

2.  The  Arms  (Brachia). — The  arms  of  the  Crinoid  body  form  the  immediate 
Prolongation  of  the  radials.     The  plates  of  the  arms  are  termed  hrachials,  and 


CLASS  III 


CRINOIDEA 


179 


are  arranged  either  in  single  or  double  alternating  rows  ;  and  hence  are  spoken 
of  as  uniserial  (Fig.  281,  A),  or  as  biserial  (Fig.  281,  B).  The  plates  of  the 
uniserial  arms  may  be  either  rectangular  or  cuiieiform,  the  major  ends  being 
directed  alternately  to  the  right  and  left.  In  biserial  arms  the  smaller  ends 
of  the  plates  meet  midway,  so  as  to  form  a  zigzag  suture.    The  arms  invariably 

B 


Fig.  279. 

Agaricocrinus  americanus 
Roein.  Ventral  disk.  r,  Uni- 
serial ambulacrals ;  i,  Inter- 
ambulacrals  ;  o,  Anally  situ- 
ated  oral ;  p,  Anterior  and 
lateral  orals  ;  x,  Posterior  in- 
terambulacrals  (after  Wach- 
smuth  and  Springer). 


Cactocrinus  probosddialis  (Hall).  A,  Plates  of  tegmen  partially 
removed  in  order  to  show  the  covered  ambulacral  passages  (a) 
leading  from  the  arms  to  the  mouth.  B,  Piated  upper  surface 
of  ambulacral  galleries.  C,  Natural  cast  of  ventral  disk  with 
impressions  of  calyx  ambulacra  (a)  leading  to  the  mouth  (o); 
an,  Anus. 


begin  uniserially,  the  biserial  structure  being  gradually  introduced  in  an  upward 
direction.  They  either  remain  simple,  or  branch  in  various  ways  ;  the  plates 
upon  which  a  bifurcation  takes  place  are  called  axillaries. 

In  the  Camerata,  the  more  highly  organised  Inadunata,  and  in  all  Eecent 


Fig.  281. 
A,   Carpocrinus  comtus  Ang.,  showing  uni- 
serial   arms.      B,   Codlicrinus  costatus  Hising., 
with  biserial  arms  (after  Angeliii). 


Fio.  282. 
Piated  ambulacral  furrows  of  the 
arms.  a,  b,  Cyathoerinns  ramo.fiui 
Ang.,  showing  covering  pioces ; 
c,  Gissocrinus  arthriticns  Hising., 
with  covering  pieces.  All  figures 
enlarged. 


Crinoids,  the  arms  are  furnished  with  pinmdes,  which  are  given  off  alternately 
from  opposite  sides,  usually  one  to  each  arm-plate,  more  rarely  on  alternate, 
or  on  every  third  arm-plate  ;  sometimes  they  are  partially  or  entirely  absent 
from  the  lower  portion  of  the  arms.  The  pinnulcs  are  jointed  appendages, 
which  at  least  basally  repeat  the  general  structure  of  the  arms,  and  in  living 


180  ECHINODERMATA— PELMATOZOA  phylum  iv 

Crinoids  lodge  the  functional  portion  of  the  genital  organs.  When  two  or 
more  arm-joints  meet  transversely  by  a  rigid  suture,  and  only  the  uj)per  one  is 
pinnule-bearing,  those  joiiits  form  a  syzygy,  whether  their  apposed  faces  are 
striated,  dotted  or  smooth.  The  lower  Joint  bearing  no  pinnule  is  called  the 
hypozygal  Joint,  the  upper  one  the  epizygal ;  and  the  two  together  constitute 
physiologically  but  a  single  segment,  as  is  shown  by  the  unaltered  alterna- 
tion  of  the  pinnules. 

The  ciliated  ambulacral  furrows  of  the  arms  enter  by  the  arm-openings 
into  the  tegmen,  and  all  converge  to  the  mouth.  Food-particles,  consisting 
chiefiy  of  diatoms,  infusorians  and  microscopic  crustaceans,  are  propelled  along 
the  furrows  and  into  the  body  by  the  action  of  the  cilia. 

In  all  Recent  and  in  numerous  fossil  Crinoids  the  brachials  and  pinnulars 
are  perforated  by  a  single,  or  in  some  cases  by  a  duplicate,  canal  {central  canal) 
containing  the  dorsal  nerve  cords,  which  give  off  four  delicate  branches 
within  each  segment.  The  dorsal  canal  extends  also  into  the  radials  and 
basals,  perforating  the  plates  when  they  are  thick,  and  running  in  a  shallow 
groove  on  the  inside  when  thin.  So  far  as  has  been  observed,  the  axial 
canals  begin  uniformly  in  the  basals,  where  they  divide  dichotomously ;  but 
in  the  radials  the  branches  generally  reunite  to  form  the  so-called  ring  canal 
(Fig.  329). 

3.  The  Column. — The  stem  or  column  attains  in  some  forms  (Pentacrinus)  a 
length  of  a  number  of  metres ;  but  in  others  it  is  much  abbreviated,  or 
even  atrophied,  so  that  the  calyx  is  either  directly  adherent  by  the  base 
(Gyathidium,  Holopus),  or  is  destitute  of  all  means  of  attachment  {Agassizocrinus, 
Uintacrinus,  Marsupites,  the  Comatulids).  The  stem  is  composed  of  usually 
short  Segments,  having  either  circular^  elliptical  or  angular  (especially  penta- 
gonal)  cross-sections,  and  being  sometimes  of  uniform  and  sometimes  of  variable 
proportions.  Lateral  appendages,  called  cirri,  are  present  in  numerous  forms, 
being  given  off  either  singly  or  in  whorls  at  regulär  intervals  along  the 
periphery.  The  larger  and  all  cirrus-bearing  segments  are  called  nodals,  and 
those  interposed  between  them  the  internodals.  The  distal  end  of  the  stalk 
may  taper  gradually  to  an  apex,  in  which  vicinity  fine  radicular  cirri  are 
commonly  developed,  or  it  may  be  thickened  at  the  extremity  so  as  to  form  a 
bulbous  or  branching  root,  or  a  heavy,  solid,  terminal  stem  plate,  or  dorso- 
central.  Growth  is  accomplished  by  the  insertion  of  new  joints  at  the 
proximal  end  of  the  stem,  either  just  beneath  the  calyx,  or  both  here  and 
between  the  earlier  formed  joints,  the  earlier  segments  becoming  at  the  same 
time  gradually  enlarged.  The  last-formed  joints  are  commonly  of  smaller 
size  than  those  situated  more  remotely  from  the  calyx. 

Like  the  brachials  and  pinnulars,  all  the  joints  of  the  stem  and  cirri  are 
pierced  by  a  (usually  central)  longitudinal  canal  which  is  circular,  oval  or 
pentagonal  in  cross  -  section,  and  communicates  with  the  peculiar  dorsal 
chambered  organ  which  in  the  Comatulids  is  situated  within  the  centrodorsal, 
and  in  the  stalked  forms  within  the  calyx  just  above  the  summit  of  the 
stem.  The  outer  walls  of  the  chambered  organ  are  composed  of  nervous 
tissue,  and  form  the  central  organ  of  the  dorsal  nervous  System  which 
innervates  all  the  dorsal  structures ;  within  the  chambered  organ  is  divided 
by  partitions  into  five  sections,  and  is  continued  ventrally  as  a  thick  tube 
of  uncertain  function,  known  as  the  central  plexus,  to  near  the  inner  surface 
of  the  disk,  where  it  ends  blindly. 


CLASS  in  CRINOIDEA  181 

All  of  the  calcareous  elements  of  which  the  dorsal  skeletal  System  is  com- 
posed  are  developed  within  a  uniform  organic  base  ;  with  the  growtli  of  the 
plates  this  within  them  becomes  a  diftuse  network,  and  between  them  forms 
a  mass  of  strong  connecting  fibrils  which  bind  the  plates  together. 

In  the  so-called  sutures  between  the  calyx  plates,  in  the  intercolumnar 
articulations  in  many  of  the  older  types  (Encrinus,  etc.),  in  the  syzygies  between 
the  brachials  in  many  forms,  and  just  below  the  cirrus-bearing  joints  in  the 
stems  of  the  Pentacrinites,  these  fibrils  are  all  of  uniform  length  and  uniformly 
distributed  over  the  Joint  face ;  but.  usually  there  is  a  diflferentiation  of  the 
fibrils  by  which  they  become  more  or  less  segregated  into  radial  groups,  as  in 
the  stems  of  Pentacrinites  ;  or  they  become  elongated  and  differentiated  into  two 
comparatively  dense  masses  separated  by  a  strong  fulcral  ridge,  and  assume  a 
more  or  less  contractile  function  as  in  the  stems  of  such  genera  as  Bhizocrinus 
and  Platycrinus,  in  the  cirri  of  the  Pentacrinites  and  Comatulids,  and  in  the 
pinnules  beyond  the  second  Joint  in  many  forms.  Between  the  brachials  they 
are  usually  differentiated  into  two  distinct  types,  one  of  which,  occupying  the 
entire  dorsal  half  of  the  Joint  face  (the  dorsal  ligament)  is  comparable  to  one 
of  the  two  masses  in  the  type  just  described ;  while  the  other,  occupying  two 
more  or  less  triangulär  areas,  one  on  either  side  of  the  central  canal  and  just 
ventral  to  the  transverse  ridge  by  which  they  are  separated  from  the  preced- 
ing  (the  interarticular  ligaments),  is  much  more  dense,  and  serves  to  bind  the 
brachials  tightly  together. 

In  addition  to  these  ligamentous  connections  there  are,  between  the 
brachials,  two  muscular  bundles  situated  on  the  ventral  border  of  the  Joint 
face,  distal  (ventral)  to  the  interarticular  ligament  masses.  "Whereas  the 
ligament  bundles  are  developed  directly  from  the  original  uniform  body 
investment  in  which  the  calcareous  elements  are  formed,  the  muscular  bundles 
have  an  entirely  separate  origin. 

In  certain  of  the  older  forms  the  proximal  segments  of  the  column 
occasionally  exhibit  simple  vertical  clefts,  which  indicate  an  original  quin- 
quipartite  composition.  These  divisions  always  occur  alternately  with  those 
of  the  basals  in  monocyclic,  and  with  those  of  the  infrabasals  in  dicyclic 
forms.  The  entire  crinoid  stem  is  probably  the  homologue  of  a  single  apical 
calyx  plate,  which  has  been  reduplicated  by  a  curious  process  of  serial  repeti- 
tion  common  among  the  Echinoderms. 

Ontogeny. — Although  we  are  as  yet  acquainted  with  the  life-history  of  but 
tbree  species,  all  belonging  to  the  genus  Antedon,  and  although  the  life- 
history  of  but  two  of  these  (A.  mediterranea  and  A.  adriatica)  is  well  under- 
stood,  the  phenomena  of  their  development  are  of  such  significance  as 
to  shed  most  valuable  light  upon  many  conditions  observed  in  fossil 
Crinoids. 

The  eggs,  extruded  from  the  ovaries  and  hanging  in  little  groups  from  the 
genital  pinnules,  are  fertilized  externally,  and  the  early  metamorphosis  of  the 
larva  takes  place  within  the  egg  membrane.  At  the  time  of  the  rupture  of 
the  egg  membrane  and  its  consequent  escape  the  embryo  (a  gastrula)  is  elongate- 
oval  in  form,  bilaterally  symmetrical,  bearing  an  anterior  tuft  of  cilia  and 
encircled  by  five  ciliated  bands,  resembling  somewhat  the  larvae  of  certain 
annelids.  Internally  there  are  to  be  seen  the  rudiments  of  five  oral  plates, 
five  basals,  three  (A.  medUerranea)  or  five  {A.  adriatica)  infrabasals,  and  about 
eleven  columnars  ;  the  orals,  basals,  and  infrabasals  are  arranged  in  horseshoe- 


182 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


shaped  bands,  and  the  columnars  are  also  horseshoe-shaped,  not  having  as  yet 
formed  complete  rings. 

After  a  free-swimming  existence  of  a  few  hours  the  embryo  attaches  itself 
by  means  of  the  so-called  adhesive  pit,  a  slight  depression  on  the  antero- ventral 
face,  the  cilia  disappear,  and  profound  changes  take  place  which  result  in  a 
rearrangement  of  the  internal  organs. 

The  five  orals  now  form  a  pyramid  over  the  superior  (ventral)  portion  of 
the  animal,  while  the  five  basals  form  a  similar,  but  inverted,  pyramid,  in  the 
wall  of  the  proximal  (dorsal)  portion  of  the  calyx  ;  between  the  apex  of  the 
latter  and  the  top  of  the  column  are  the  three  or  five  infrabasals.  The  column 
consists  of  about  eleven  cylindrical  joints,  each  composed  of  the  original  central 
annulus  from  which  numerous  longitudinal  parallel  calcareous  rods  are 
developed,  and  is  terminated  distally,  and  attached,  by  a  lobate  terminal  stem 
plate.     The  larva  is  now  said  to  have  reached  the  "  Cystid  stage." 

In  the  five  diamond-shaped  spaces  which  occur  between  the  divisions  of 
the  orals  and  basals  the  radials  appear,  and,  increasing  rapidly  in  size,  intrude 
upon  the  orals  ;  at  the  same  time  a  sixth  plate  (the  anal) 
makes  its  appearance  in  the  zone  of  the  radials,  but  it  gradu- 
ally  moves  upward  with  the  orals  into  the  ventral  disk.  A 
row  of  elongate  cylindrical  segments,  bifurcating  on  the 
second,  is  given  ofF  from  each  radial,  and  grows  very  rapidly 
by  the  addition  of  ne\7  plates  at  its  distal  end.  The  column 
ceases  adding  new  segments,  and  the  last  one  to  be  formed, 
just  beneath  the  calyx,  increases  in  size  and  fuses  with  the 
infrabasals  to  form  the  rudiment  of  the  centrodorsal.  The 
larva  is  now  said  to  have  reached  the  "  Pentacrinoid  stage." 
Simultaneously  with  the  development  of  the  arms  and 
column  a  resorption  of  the  orals  and  the  anal  sets  in,  while 
the  basals  begin  to  undergo  a  curious  metamorphosis  by 
which  they  are  transformed  into  a  lobate  ten-rayed  plate 
which  is  wholly  internal,  lying  just  above  the  chambered 
organ.  Finally  the  button-shaped  centrodorsal,  which  is  now 
beset  with  numerous  cirri,  detaches  itself  from  the  remainder 
of  the  stalk,  and  the  animal  becomes  free. 

The  ontogeny  of  the  Antedon  (Fig.  283)  reveals  the  fact 
that  the  infrabasals,  basals,  orals  and  stem  represent  the 
most  primitive  skeletal  structures,  while  the  radials  and 
brachials  are  formed  at  a  subsequent  period.  Similar 
evidence  is  afforded  by  numerous  fossil  Crinoids,  in  which 
the  basals  and  column  are  very  strongly  developed,  while 
the  radials  are  mostly  of  inferior  size,  and  the  arms  either 
rudimentary  or  absent.^ 
Hahitat. — The  existing  Crinoids  inhabit  depths  ranging  from  between  tide 
marks  to  2900  fathoms,  both  extremes  being  occupied  by  unstalked  forms 

^  [Some  of  tlie  Paleozoic  Flexibilia  are  almost  identical,  in  fact,  with  the  pedunculate  stages  of 
Antedon,  Wachsmuth  and  Springer,  from  their  observations  on  the  orientation  of  the  stem  and  its 
caiial  in  fossil  mouocyclic  and  dicyclic  Crinoids,  were  led  to  infer  the  presence  of  infrabasals  in  the 
nepionic  (or  larval)  stages  of  many  forms  previonsly  supposed  to  be  witlioiit  them.  This  predic- 
tiou  was  abundantly  contirmed  by  Mr.  Bury's  discovery  of  niinnte  infrabasals  in  the  larva  of  Antedon. 
See  especially //.  Bury,  Early  Stages  in  the  Development  of  Antedon  rosaceus.  Philos.  Trans., 
1889,  vol.  clxxix.] 


Larva  of  Antedon 
roscbceus  Linck.  b,  Ba- 
sals ;  r,  Radials ; 
0,  Orals :  cd,  Centro- 
dorsal (after  Wyville 
Thomson). 


CLAss  III  CRINOIDEA  183 

(Comatulids),  the  ränge  for  the  stalked  species  being  from  5  to  2325 
fathoms.  The  great  majority  of  the  existing  types  are  littoral  and  snblittoral, 
oidy  a  few  descending  into'the  abysses.  A  very  large  nnnib(3f  of  species, 
many  genera,  and  several  families  are  confined  to  the  East  Indian  region,  while 
all  the  species  and  genera  occurring  outside  of  that  region  have  close  relatives 
within  it.  Most  forms  are  highly  gregarious,  occurring  in  great  numbers 
together,  these  masses  being  often  composed,  in  the  East  Indies,  of  twenty  or 
more  different  species,  but  a  few  appear  to  be  more  solitary  in  habit.  As  a 
rule  the  Eecent  forms  are  very  local,  and,  though  they  may  be  found  in  certain 
very  restricted  areas  in  large  numbers,  and  may  have  a  very  wide  geographical 
ränge,  it  is  comparatively  seldom  that  one  meets  with  them. 

Fossil  Crinoids  also  appear  to  have  been  gregarious  in  habit,  and  their 
remains  are  frequently  found  commingled  with  those  of  reef-building  corals 
in  Paleozoic  strata.  Owing  to  the  extremely  delicate  Constitution  of  many  of 
the  skeletal  parts,  and  the  looseness  with  which  the  plates  and  segments  are 
united,  the  Crinoid  organism  is  by  no  means  favourably  adapted  for  preserva- 
tion  in  the  fossil  state.  Perfect  crowns  are  of  comparatively  rare  occurrence, 
calices  more  frequent ;  but,  on  the  other  hand,  detached  joints  of  the  stem 
and  arms  are  often  very  abundant,  and  form  beds  of  considerable  thickness. 
Orinoidal  limestones  of  greater  or  lesser  extent  are  met  with  in  numerous 
formations  from  the  Ordovician  to  the  Jura ;  those  of  the  Carboniferous  and 
Muschelkalk  (Trochitenkalk)  being  especially  characteristic. 

Classification. — The  first  attempt  to  construct  a  Classification  of  the 
Crinoids  was  that  of  J.  S.  Miller  in.  1821.  Four  groups  differing  in  the  form 
and  mode  of  union  of  the  calyx  plates  were  distinguished  by  Miller  as 
follows  :  C.  articulata,  semiarticulata,  inarticulata  and  coadunata.  The  Classi- 
fication of  Johannes  Müller,  in  1841,  was  based  upon  a  number  of  difFerential 
characters,  such  as  the  articular  or  close  suture  of  the  radials,  the  thick- 
ness of  the  calyx  plates,  the  mobility  of  the  arms,  and  the  plated  or 
cbriaceous  character  of  the  ventral  disk.  Two  principal  groups  were 
recognised  :  Articulata  and  Tesselata ;  while  a  third  (Costata)  was  constructed 
for  the  reception  of  the  unique  genus  Saccocoma.  T.  and  T.  Austin  and 
F.  Roemer  adopted  the  untenable  divisions  of  Stalked  and  Unstalked 
Crinoids. 

The  importance  of  Wachsmuth  and  Springer's  investigations  on  the 
structure  of  the  calyx,  especially  of  the  tegmen,  and  on  the  orientation  of 
the  stem  and  its  canals  in  monocyclic  and  dicyclic  forms,  cannot  be  over- 
estimated.  Two  groups  were  proposed  in  their  Classification  of  1879 : 
Palaeocrinoidea  and  Stomatocrinoidea  (  =  Neocrinoidea,  Carpenter) ;  groups  which 
correspond  in  the  main  with  the  Tesselata  and  Articulata  of  Johannes  Müller. 
This  Classification  was  subsequently  abandoned,  and  a  new  one  suggested  for 
it  in  1888,  afterwards  more  fully  defined  in  their  monograph  on  the  North 
American  Crinoidea  Camerata  in  1897,  in  which  three  principal  grand 
divisions,  or  Orders,  were  recognised,  which  were  believed  to  include  sub- 
stantially  all  Crinoids,  fossil  and  recent,  viz.:  Camerata,  Inadunata  and 
Articulata. 

Jaekel  in  1894  proposed  two  Orders,  Cladocrinoidea  and  Pnitnmnmdea, 
the  former  containing  only  the  Camerata  (W.  and  Sp.),  and  the  Int  t er  ;ill  the 
rest.  Bather  in  1898  divided  the  Crinoids  according  to  the  composition  of 
the  base  into  two  subclasses,  Monocyclica  and  Dicyclica,  recognising  for  the 


184  ECHINODERMATA— PELMATOZOA  phylüm  iv 

most  partj  as  subordinate  to  them,  the  Orders  proposed  by  Wachsmuth  and 
Springer.  The  divisions  established  by  Wachsmuth  and  Springer  have  been 
adopted  as  the  basis  of  the  following  systemätic  arrangement,  substituting, 
however,  for  their  Artioulata  the  preferable  name  Flexibilia,  proposed  by  von 
Zittel  in  1895,  and  now  adopted  by  Springer  in  his  forthcoming  monograph 
of  that  group;  also  retaining  the  name  Articulata  in  the  sense  of  Miller  and 
Müller  for  a  fourth  division,  including  the  Eecent  and  most  of  the  Mesozoic 
Crinoids. 

Within  the  last  few  years,  also,  the  terminology  has  been  amended  in 
several  important  respects ;  and  conformably  to  the  usage  of  the  leading 
English  and  American  authorities,  certain  of  these  changes  have  been  adopted 
in  the  present  edition.  An  explanatory  note  on  the  use  of  terms  is  therefore 
given  at  this  place,  in  order  to  facilitate  reference,  and  to  exhibit  the  corre- 
spondence  between  the  older  terminology  and  the  new. 

The  only  abbreviations  employed  in  the  text  are  the  following  : — 


75=  Infrabasal. 

^r  =  Brachial. 

5  =  B£fsal. 

/5r=  Primibrach  or  costal. 

i?^  =  Radianal. 

/Zßr  =  Secundibrach  or  distichal. 

X  —  First  or  special  anal. 

iBr  =  Interbrachial. 

i2  =  Radial. 

Amh  =  Ambulacrals. 

In  addition  to  these  the  following  are  used  in  the  figures,  but  are  printed 
in  small  letters  : — 

^=Calyx.  .    6'  =  0rals. 

A  =  Arms.  IE  =  Interradials. 

St  =  8tem..  Z)ts^  =  Distichais. 


Explanation  of  Terms. 

Crotöti=:Crinoid  minus  the  steni. 

Calyx  =  Crinoid  skeleton  minus  the  stem  and  free  arms. 

Dorsal  cup  =  All  parts  of  the  calyx  below  the  origin  of  the  free  arms. 

Tegmen  —  Thsit  part  of  the  calyx  lying  above  the  origin  of  the  free  arms,  and  embracing 
the  disk  ambulacra,  the  mouth,  and  the  anus.  Inchides  the  terms  ventral  disk,  vaiilt, 
dorne,  summit,  etc. 

Base~T\idit  part  of  the  dorsal  cup  lying  next  to  the  column.  It  may  be  composed  of  one 
ring  of  plates  (monocyclic),  or  of  two  rings  (dicyclic),  which  are  distinguished  as  basals  and 
infrahasals .  The  basals  adjoin  the  radials  and  alternate  with  them,  being  interradial  in 
Position.     The  infrahasals,  when  present,  form  the  proximal  ring,  and  are  radially  disposed. 

Badials  =  Th.e  circlet  formed  by  the  first  plate  in  each  of  the  rays  ;  or,  the  radially 
situated  circlet  of  plates  above  the  basals,  and  this  ring  only.  In  some  of  the  earlier  Crinoids 
one  or  more  of  the  radials  appear  as  if  transversely  bisected,  due  to  the  presence  of  a 
radianal  or  inferradials. 

Brachials  =  k\\  plates  beyond  the  radials  in  radial  succession.  They  are  called  fixed 
brachials  so  far  as  they  take  part  in  the  calyx  ;  free  brachials  or  arm-2')lates  when  they  do 
not.  The  brachials  forming  the  first  circlet  above  the  radials,  whether  free  or  fixed,  are 
called  primibrachs  or  costals  ;  those  of  the  second  order  secundibrachs  or  distiehals  ;  those  of 
the  third  order  tertibrachs  or  palmars;  and  so  on  for  succeeding  orders  of  brachials,  to  which 
fofmerly  the  name  post-palmars  was  applied. 

Interradials  =  AM  plates  occupying  the  spaces  between  the  rays  proper,  whether  they 
belong  to  the  dorsal  cup  or  the  ventral  disk.  Those  of  the  dorsal  cup,  which  are  inter- 
posed  between  the  brachials,  are  distinguished  as  interbracMah,  and  those  of  the  tegmen, 
which  lie  between  the  ambulacra,  as  inter ambulacrals. 

Radianal  =  A  plate  disturbing  the  bilateral  symmetry  of  the  cup,  located  primitively 
directly  below  the  right  posterior  radial,  and  in  later  genera  obliquely  to  the  left  of  it. 

^710.^5=  Interradials  of  the  posterior  side,  forming  the  base  of  the  anal  structures.  The 
special  or  first  anal  plate  (npw  usually  designated  x),  when  present,  invariably  rests  upon 
the  truncated  upper  face  of  the  posterior  basal  and  between  the  radials.     Higher  anal  plates 


CLASS  III  CRINOIDEA  185 

niay  Le  present,  even  wlien  the  s[»ecial  anal  is  wanting  ;  tlioy  are  interposed  betvveen  tlie 
iiiteibracliials,  following  tlie  median  line  of  the  posterior  area. 

Urals ^The  five  large  interradial  plates  which  Surround  the  niouth  or  cover  it.  They  are 
Said  to  be  symmetrical  when  of  nearly  tlie  same  size  and  form  ;  asymmetrical  when  the 
posterior  plate  is  pushed  in  betvveen,  or  is  larger  than,  the  other  four. 

Ambulacrals  =  The  rows  of  small  plates  in  the  tegmen  which  are  radially  situated.  They 
consist  of  adamhulacrals  or  side-pieces,  and  the  covering-])latcs  (Saumplättchen).  The  former, 
when  present,  constitute  the  outer,  the  latter  the  inner  rows  of  plates.  The  covering  plates 
form  a  roof  over  the  food-grooves  ;  they  are  generally  represented  by  two  alternating  rows 
of  small  plates,  more  or  less  regulär  in  their  arrangement,  which  are  movable  upon  the  arms 
and  pinnules,  but  upon  the  disk  only  in  those  Crinoids  in  which  the  mouth  is  exposed. 

The  orientation  is  based  upon  the  natural  position  of  the  Crinoid,  with  the  arms  upper- 
most,  and  viewing  the  specimen  from  the  anal  side.  The  anal  interradius  will  then  be 
posterior,  the  radius  opposite  to  it  anterior,  while  the  right  and  left  sides  of  it  correspond 
with  right  and  left  of  the  observer, 

Primary  Divisions  of  the  Crinoidea. 
I. 

Crinoids  in  which  tlie  lower  brachials  take  part  niore  or  less  in  the  dorsal  cup. 
All  plates  of  the  calyx  united  by  close  suture.  Mouth  and  food-grooves  closed. — 
Order  1.     Game  rata. 

II. 

Crinoids  in  which  the  lower  brachials  are  incorporated  into  the  calyx  either  by 
lateral  union  with  each  other,  or  by  nieans  of  a  skin  studded  with  calcareous  particles. 
All  plates  from  the  radials  up  movable.  Mouth  and  food-grooves  exposed.  Arms 
non-pinnulate.  The  top  stem  Joint  often  fused  with  the  infrabasals,  and  not  always 
the  youngest  Joint  of  the  stem. — Order  2.  Flexibilia  of  Zittel  {  =  Ärticulata  of  W. 
and  Sp.  non  Miller  and  Müller). 

III. 

Crinoids  in  which  the  brachials  are  free  above  the  radials.  Plates  of  calyx  united 
by  close  suture.     Mouth  sub-tegminal. — Order  3.     Inadunata. 

IV. 

Crinoids  in  which  the  mode  of  union  of  radials  with  the  plates  they  l)ear  is  by 
complete  muscular  articulation,  and  in  which  are  combined  the  following  additional 
charäcters :  open  mouth  and  food  grooves ;  dorsal  canals  perforating  radial  and  arm 
plates ;  uniserial  arms  only ;  pinnules  ;  the  general  presence  of  a  modified  columnal, 
or  proximale  ;  the  general  absence  of  bilateral,  and  presence  of  pentamerous  symmetry, 
modified  only  by  loss  or  addition  of  rays  and  not  by  anal  structures.  Brachials  either 
free,  or  more  or  less  incorporated. — Order  4.     Articülata. 

The  first  three  of  these  divisions  are  represented  in  the  Ordovician.  The  Gamerata 
were  the  most  specialised,  and  the  first  to  disappear,  being  confined  to  the  Paleozoic, 
and  becoming  extinct  in  the  Lower  Goal  Measures.  The  Flexibilia  were  similarly 
limited.  The  Articülata  ränge  from  the  Mesozoic  to  the  present  time.  The  Inadunate 
type,  representing  the  most  generalised  structure  of  the  Crinoids,  is  in  its  most 
essential  feature,  though  variously  modified,  carried  forward  with  the  Ärticulata^  and 
thus  has  an  unbroken  ränge  from  the  earliest  Ordovician  to  the  present. 

Order  1.     CAMBRATA  Wachsmuth  and  Springer. 

(Sphaeroidocrinacea  Neumayr.) 

Crinoidea  in  which  the  lower  brachials  take  part  in  the  doisal  cup.  ylll  plates  of 
tli£  calyx  united  hy  close  sutures,  and  immovahle.     Mouth  and  food-grooves  completely 


186  ECHINODERMATA— PELMATOZOA  phylüm-  iv 

covered  ;  the  covering  pieces  of  the  latter  frequently  incorporated  in  the  tegmen.  Anal 
opening  eccentric  or  subcentral,  frequentUj  situated  at  the  end  of  a  prohoscis-like  anal 
tube.     Arms  uniserial  or  hiserial,  and  pinnulate.     Ordovician  to  Carboniferous. 

In  some  of  the  earlier  (Ordovician)  forms,  as  in  the  Reteocrinidae  and 
Batocrinidae,  there  is  considerable  flexibility  in  the  tegmen,  which  is  com- 
posed  of  innumerable  small  plates ;  but  the  mouth  and  food  grooves  in  all 
these  are  perfectly  subtegminal,  thus  distingirishing  them  from  the  Flexibilia, 
some  of  which,  in  respect  to  flexibility  of  the  tegmen,  they  superficially 
resemble. 

Family  1 .     Oleiocrinidae. 

Dicydic.  Brachials  to  height  of  several  orders  incorporated  in  calyx  hy  lateral 
Union,  those  of  different  rays  in  contact  except  at  the  anal  side.  Calyx  plates  furnished 
with  pore-rhomhs  crossing  the  sutures  as  in  some  Cystoidea.  Arms  pinnulate.  Tegmen 
of  small  undifferentiated  plates.     Mouth  subtegminal.     Ordovician, 

Cleiocrinus  Billings  (emend.).  Calyx  large,  pliant ;  plates  joined  by  loose 
sutures,  crossed  by  pore-rhombs.  IBB  five,  invisible  exteriorly.  Basais  and 
radials  not  in  typical  succession,  but  alternating  with  each  other  in  a 
horizontal  ring  of  ten  plates  surrounding  the  IBB  and  projecting  downward 
over  the  column  like  a  collar.  No  iBr  except  at  the  anal  side ;  anals  in 
vertical  series,  resting  on  the  truncate  posterior  basal,  and  extending  high  up 
between  the  rays.  Rays  and  their  divisions  up  to  the  free  arms  contiguous 
and  interlocking ;  brachials  bifurcating  several  times  in  the  calyx,  giving  off 
fixed  pinnules,  which  are  incorporated  by  lateral  union  with  adjacent  brachials 
and  become  free  between  the  arm  bases.  Arms  small,  uniserial  and 
unbranched.  Column  obtusely  pentagonal,  or  nearly  round.  Lowest 
Ordovician  (Chazy  and  Trenton) ;  Canada  and  the  United  States. 

This  genus  has  the  flexible  calyx  and  loose  sutures  of  the  Flexibilia,  but  its  innnulate 
arms  and  subtegminal  mouth  place  it  in  closer  relation  with  early  Camerata,  such  as 
Reteocrinus.  Its  calycine  pore-rhombs  proclaim  its  not  distant  derivatiou  from  the  Cystids. 
In  the  remarkable  disposition  of  the  basal  and  radial  plates,  in  horizontal  alternation  instead 
of  vertical  succession,  touching  the  infrabasals  by  their  exterior  surface  instead  of  the  distal 
edge,  this  form  diff"ers  from  all  known  Pelmatozoa.  These  intermediate  and  peculiar 
features  accord  with  its  very  early  age. 

Family  2.     Reteocrinidae.     Wachsmuth  and  Springer  (emend.). 

Dicydic.  The  lower  plates  of  the  rays  more  or  less  completely  separated  from 
those  of  other  rays,  and  from  the  primary  interradials,  by  irregulär  supplementary 
pieces,  without  definite  arrangement.  Anal  interradius  divided  by  a  vertical  row 
of  conspicuous  plates.     Ordovician. 

Reteocrinus  Billings  (em.  W.  and  Sp.).  Dicydic.  IBB  five,  variable.  PiR 
and  fixed  brachials  folded  into  a  strong  median  ridge,  which  follows  the 
bifurcations  and  passes  insensibly  into  the  arms.  A  similar  ridge  of  anal 
plates  divides  the  posterior  interradius,  extending  to  the  anal  opening. 
Radials  separated  all  around.  Arms  usually  branching;  uniserial,  or  with 
interlocking  cuneate  ossicles.  Interbrachial  areas  filled  with  innumerable 
minute  pieces  forming  an  apparently  pliant  integument  continuous  with  the 
tegmen.  Column  round  or  pentagonal.  Ordovician  (Trenton  to  Cincinnatian) ; 
North  America. 


CLASS  III 


CRINOIDEA 


187 


Family  3,     Dimerocrinidae  Bather.     (Glyptocrinidae  Zittel  pars  ;  Glyptasteridae 
Aiigelin  ;   Thysanocrinidae  W.  and  Sp.) 

Dimjclic.  Lower  hrachials  and  interhrachials  forming  an  important  pari  of  the 
dorsal  cup  ;  interbrachial s  well  defined.  Radiais  in  contad  except  at  the  posterior 
side,  where  theij  are  separated  hy  an  anal  plate.     Ordovician  to  Devonian. 


Ptychocrinus  W.  and  Sp.  IBB  five.  Arms  uniserial,  simple,  or  branching 
once.  Radial  and  brachial  plates  marked  by  well -defined  median  ridge. 
First  anal  plate  usually  succeeded  by  three  plates  in  second  ränge ;  iBr  few. 
Anus  without  a  tube.     Ordovician ;  America. 

Orthocrinus  Jaekel.     Arms  stout  and  uniserial.     Devonian  ;  Germany. 

Bimerocrinus  Phillips.  (Thysanocrinus  3^nd  Glyptaster  Hall;  Eucriiius  Ang.) 
(Fig.  284).  IBB  five.  Arms  biserial,  simple  or  branching.  First  anal  plate 
followed  by  three  in  second 
ränge ;  iBr  in  several  ranges. 
Anus  without  a  tube.  Silurian 
to  Devonian ;  North  America, 
England,  Gotland. 

Cyphocrinus  S.  A.  Miller 
(Hyptiocrinus  W.  and  Sp.).  Calyx 
constructed  as  in  Dimerocrinus, 
but  low  and  wide,  with  arms 
pendent  and  tegmen  plates  spini- 
ferous.    Silurian;  North  America. 

Gazacrinus  S.  A.  Miller  (Idio- 
crinus  W.  and  Sp.).  iBr  limited 
to  a  Single  large  plate  in  each 
interradius,  that  of  posterior  side 
following  an  anal.  Silurian ; 
North  America. 

Lampterocrinus  Roemer.  Calyx 
like    that    of    Dimerocrinus,    but         Dinurocnnus. 
asymmetrical    from    bulging    at 

anal  side,  and  with  anus  at  end  of  a  tube.  Anal  plate  followed  by  three 
IBB,  large.  Rays  produced  into  five  tubulär  extensions,  bearing  biserial, 
pinnuliferous  arms  on  each  side.     Silurian ;  North  America. 

Siphonocrinus  S.  A.  Miller.  Similar  to  preceding,  but  IBB  small,  calyx 
larger  and  more  asymmetric,  from  subtegminal  recurving  of  the  rectum. 
Silurian  ;  North  America. 


Fig.  284. 
Analysis  of  calyx  (after  W.  and  Sp.). 


Family  4.     Rhodocrinidae  Roemer. 

Dicyclic.  Lower  hrachials  and  interhrachials  forming  an  important  part  of  the 
dorsal  cup.  Radiais  separated  all  around  hy  an  interradial  plate  followed  hy  well- 
defined,  definitely  arranged  interhrachials.  Infrahasals  five.  Anal  area  slightly, 
and  often  not  at  all,  different  from  those  of  other  interrays.  Ordovician  to  Lower 
Carboniferous. 

Rhaphanocrinus  W.  and  Sp.  (Coelocrinus  Salter).     Calyx  obovate.     Arms 


188 


ECHINODEEMATA— PELMATOZOA 


PHYLÜM  IV 


Bliodocrinus. 


Fig.  285. 

Analysis  of  calyx  (after  W. 
and  Sp.). 


uniserial ;  from  ten  to  twenty,  and  branching  further.     Otherwise  similar  to 

Ärchaeocrinus.     Ordovician ;  North  America  and  England. 

Archaeocrinus  W.  and  Sp.     Calyx  obovate  to  hemispherical ;  base  usually 

concave  or  invaginate.     IBB  small.     Brachials  to  at  least  second  order  in- 

corporated   in   the   calyx.     Arms    biserial,   usually   ten   at   their   origin   and 

branching  beyond.  Anal  interradius 
slightly  distinguished  by  an  additional 
plate  in  second  ränge ;  iBr  numerous. 
Anus  without  a  tube.  Ordovician;  Canada 
and  Kentucky. 

Diabolocrinus  W.  and  Sp.  Calyx  de- 
pressed  globose.  Anus  at  end  of  a  tube. 
First  regulär  interbrachial  frequently 
surrounded  by  supplementary  plates. 
Ordovician ;  Tennessee. 

Deocrinus  and  Hercocrinus  Hudson. 
Ordovician ;  Canada. 

Bhodocrinus  J .  S.  Miller  {Acanthocrinus 
Koemer)  (Fig.  285).  Calyx  globose, 
usually  small  and  delicate,  with  concave 
base,  and  constricted  at  the  tegmen. 
Arms  becoming  free  at  the  distichals,  and 
branching ;  biserial,  either  directly  from 
the  calyx  up,  or  only  from  the  last  bi- 

furcation.     Anal  side  frequently,  but  not  always,  distinct  from  the  regulär 

interbrachial  areas,  by  interposition  of  an  extra  plate  in  the  second  ränge. 

Devonian  to  Lower  Carbon-  4  ß 

iferous  (Keokuk  Gr.);  North 

America,  England,  Belgium, 

Germany. 

Gilbert  socrinus       Phillips 

{Goniasteroidocrinus  Lyon  and 

Cass.;  Ollacrinus  Cumberland 

nomen  nudum).    Calyx  below 

the  arm-regions  like  that  of 

Bhodocrinus,      but      usually 

larger,     expanding    at    the 

tegmen  instead  of  constrict- 

ing,  and  distinguished  especi- 

ally    by    large    tubulär   ap- 

pendages  extending  outward 

and     downward    from    the 

margin  of  the  tegmen,  and 

overhanging  the  arm  bases. 

These  appendages  are  f ormed 

of  rows  of  cylindrical  plates, 

pierced  to  their  füll  length 

by  a  central  canal ;  they  are 

primarily  ten  in  number,  in  some  species  free,  and  in   some  fused  by  their 

outer  margins  to  those  of  adjacent  rays.     Arms  small,  delicate,  biserial,  given 


Fio.  286. 
lihipidocrinus  crenatus  (Goldf.).  Devonian ;  Gerolstein,  Eifel. 
A,  Perfect  crown,  of  the  natural  size  (after  Schnitze).  B,  Tegmen, 
with  eccentric  anus.  C,  Interior  view  of  the  base,  showing  the  flve 
IBB,  two  of  the  basals  and  one  radial.  D,  Cohunn.  E,  Face  of  stem- 
joint. 


CLASR  in  CRINOIDEA  189 

off  in  Clusters  beneath  the  appendages.  Anus  subcentral,  directly  through 
the  tegmen.  Devonian  to  Lower  Carboniferous  (Keokuk  Gr.) ;  North 
America,  Great  Britain  and  Belgium. 

Lyriocrinus  Hall  {Marsiipiocrinus  Hall,  non  Blv.  nee  Phill.).  Calyx  depressed 
hemispherical,  with  base  rather  truncate  ;  tegmen  almost  flat,  composed  of 
numerous  small,  irregulär  plates.  Plates  of  dorsal  cup  usually  smooth  or 
granulär.  Arms  ten,  strong,  unbranched,  biserial.  Interbrachials  few,  incor- 
porating  brachials  to  only  part  of  the  second  order.  Anal  side  usually  not 
distinct ;  anus  eccentric,  at  the  end  of  a  small  tube.  First  interradials  some- 
times  touch  basals.     Silurian  ;  North  America  and  England. 

Thylacocrinus  (Ehlert.  Kesembling  Lyriocrinus,  but  calyx  more  elongate, 
and  i.Br  profusely  developed  ;  anal  side  slightly  distinct.  Arms  twenty  or 
more,  biserial,  and  not  branching  in  the  free  State.  Devonian ;  France, 
Germany  and  North  America. 

Änthemocrinus  W.  and  Sp.  Has  one  costal  and  few  iBr.  Arms  biserial, 
branching.     Silurian ;  Gotland. 

Bhipidocriniis  Zittel  (ex  Beyrich  MS.)  (Fig.  286).  Calyx  similar  to  that  of 
Lyriocrinus.  Plates  highly  ornamented.  Rays  produced  into  two  long,  heavy, 
uniserial  trunks,  giving  off  biserial,  pinnuliferous  ramules  alternately  on  either 
side.     Middle  Devonian  ;  Eifel,  Germany. 

Diamenocrinus  (Ehlert.  Arms  uniserial,  repeatedly  branching.  Devonian  ; 
France  and  Germany. 

Lahuseniocrinus  Tschern. ;   Condylocrinus  Eichw.     Devonian  ;  Ural. 

Ophiocrinus  Salter  {non  Charlesworth,  nee  Semper  nee  Angelin).  Devonian  ; 
South  Africa. 

Family  5.     Melocrinidae  Zittel  (emend.  W.  and  Sp.). 

Monocyclic.  Lower  brachials,  with  well-defined  interbrachials  between  them, 
forming  part  of  dorsal  cup.  Radiais  in  contact  all  around.  Ordovician  to 
Devonian. 

Glyptocrinus  Hall  (Canistrocrinus  W.  and  Sp.,  Pycnocrinus  S.  A.  Miller). 
(Fig.  287.)  Basals  five.  Dorsal  cup  obconical  to  subglobose,  ornamented 
with  radiating  Striae  passing  from  plate  to  plate  ;  the  eleva- 
tions  following  the  rays  pronounced,  and  forming  well-defined 
rounded  ridges,  which  meet  imperceptibly  with  the  free  arm- 
plates.  Interbrachials  very  numerous,  and  enclosing  supple- 
mentary  anals  on  the  posterior  side,  which  sometimes  form  a 
continuous  series.  There  are  also  numerous  interdistichals, 
and  frequently  interpalmars,  which  form  conspicuous  depres- 
sions  between  the  arm-plates.  Tegmen  low,  composed  of 
minute  irregulär  pieces ;  anus  eccentric.     Arms  uniserial,  ten 

to   twenty,  branching  in   the  free  state,   long  and   slender.  

Column  round,  or   exceptionally   pentangular.     Ordovician;  pio.  287. 

North  AnTerica.  Giyptocrmus  dem- 

Schizoerinus   Hall.      Ordovician  (Trenton  Group);    New  atici?n"'(cYnK 

V^».1^  natian);    Cincinnati, 

JLOrK.  i         X  T)        1        f  '^hio.     Natural  size. 

Stelidiocrinus    Ang.    {Harmocnnus   Ang.).       Basals    tour. 
Form  of  dorsal  cup  as  in  Glyptocrinus,  but  interbrachials  fewer  and  much 
larger,  and  plates  generally  without  ornamentation.     Plates  of  the  tegmen 


190 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


also  comparatively  large.     Arms  uniserial,  sometimes  interlocking.     Silurian  ; 
Europe  and  North  America. 

Periglyptocrinus  W.  and  Sp.  Basais  five.  Arms  biserial,  dichotomous. 
Ordovician  (Trenton  Gr.) ;  Canada  and  Kentucky. 

Scyphocrinus  Zenker.  Basais  four.  Arms  uniserial,  dichotomising  fre- 
quently.  Calyx  very  large  and  elongate.  Symmetry  of  dorsal  cup  slightly 
disturbed  by  anals  which  are  interposed  between  the  interbrachials.  Brachials 
to  lower  part  of  the  third  order  incorporated  in  the  calyx,  the  upper  ones  free. 
Interbrachials  very  numerous.  Stem  attached  to  a  large,  hollow  spheroid, 
strengthened  by  internal  septa,  regarded  as  a  float  by  Hall  ( =  Camarocrinus), 
as  a  Cystid  by  Barrande  ( =  Loholithus).  Silurian  and  Devonian  ;  Europe  and 
North  America. 

Mariacrinus  Hall  (Zenkericrinus  Waag.  and  Jahn).  Basais  four.  Arms 
uniserial,  branching  once  or  twice.  In  general  aspect,  construction  of  calyx, 
and  surface  Ornament,  resembling  Glyjptocrinus.     Silurian ;  America,  Europe. 

Melocrinus  Goldf.  (Ctenocrinus  Bronn,  Astrocrinus  Conrad,  Turbinocrinus 
Troost,  Castanocrinus  Eoemer,  Clonocrinus  Ö^hlert,  Promelocrinus  Jaekel). 
(Figs.  288,  289).     Basais  four;  interbrachials  numerous;  those  of  the  posterior 

interray  enclosing  one  or  more 
supplementary  anals.  Anal  aper- 
ture  eccentric,  rarely  extended  in 
a  small  tube.  Rays  produced  into 
two  main  uniserial  rami,  giving  off 
biserial,  pinnule-bearing  arms  at 
short  intervals  to  the  outside  of 


Fig.  288. 

Melocrinus  typus  (Bronn).  Uevoiiian  (Spiriferen-Sandstein) ; 
Dann,  Bifel.  B,  Basais.  C,  Mould  of  stem-joints  (the  so- 
called  "  Schranbensteine  "). 


Fig.  289. 

Melocrinus.    Analysis  of  calyx  (after  W. 
and  Sp.). 


the  bifurcation  ;  the  rami  may  be  separate  (Silurian  species),  or  more  or 
less  fused  by  their  inner  margins  (Devonian  species).  Column  roun(?r  Silurian 
and  Devonian  ;  Gotland,  England,  Germany  and  North  America. 

Cytocrinus  Roemer.  Like  Melocrinus,  but  with  arms  borne  on  a  single  main 
radial  trunk  from  each  ray.     Silurian ;  America. 

Clonocrinus  Quenstedt.  {non  CEhlert ;  Corymhocrinus  Ang. ;  Polypeltes  Aug.). 
Basais  four,  hidden  by  column.     Arms  dichotomous,  biserial  both  above  and 


CRINOIDEA 


191 


)elow  the  bifurcations.  Base  concave,  forming  an  inverted  cup.  Dorsal  cup 
itrictly  pentamerous ;  no  anal  plate.  Interbrachials  large,  not  enclosing  any 
mal  plates.      Silurian  ;  England,  Gotland  and  North  America. 

Tribliocrinus  Geinitz  (Spyridiocrinus  Oihlert).  Lower  Devonian ;  Germany 
tnd  France. 

Technocrinus  Hall.  Like  Melocrinus,  but  having  ten  strong,  simple,  biserial 
'arms,  which  do  not  bifurcate  in  the  free  State.  Interbrachials  not  enclosing 
supplementary  anals.     Devonian  (Oriskany) ;  Maryland. 

Macrost i/locrinus  Hall.  Basais  three,  unequal.  Anal  interradius  much 
wider  than  the  others ;  its  first  row  consisting  usually  of  three  plates,  while 
that  in  the  four  other  interrays  consists  of  a  single  inter- 
brachial. Arms  ten,  simple  and  biserial.  Silurian;  North 
America. 

Patelliocmius  Ang.  (Fig.  290).  Basais  three,  unequal. 
Arms  biserial  or  of  cuneate  uniserial  brachials.  No  anal 
plates.  Dorsal  cup  elongate.  Silurian ;  Gotland,  North 
America. 

Allocrinus  W.  and  Sp.  Basais  three,  unequal.  Arms 
uniserial.  No  anal  plates.  Dorsal  cup  depressed.  Inter- 
brachials few,     Silurian ;  North  America. 

Briarocrinus  Angelin.     Silurian  ;  Gotland. 

Centriocrinus  Bather  (pro  Cenirocrinus  W.  and  Sp.,  non 
Austin,  nee  Worthen).  Basais  fused.  Dorsal  cup  depressed. 
No  anals.     Arms  unknown.     Devonian  ;  North  America. 

Dolatocrinus  Lyon  (Cacabocrinus  Hall).  Dorsal  cup  per- 
fectly  pentamerous,  cup-shaped  or  saucer-shaped.  Base  u^ian ;  Gotland. 
usually  concave.  Basais  primitively  three,  but  completely  ^^*^"r?\  ^^'"^^  ^^^^ 
anchylosed  in  the  adult.  Costals  two  ;  iBr  few,  the  first 
ones  extremely  large.  Tegmen  comparatively  flat,  and  composed  of  rather 
large  plates,  of  which  the  orals  form  the  summit.  Respiratory  pores  be- 
tween  arm  bases  frequently  present.  Anus  at  the  end  of  a  short  tube. 
Arms  little  known,  sometimes  branching  and  biserial.  Column  with 
numerous  projecting  rings  and  buttresses.     Devonian  ;  North  America. 

Stereocrinus  Barris.  Like  the  preceding,  but  the  anchylosis  of  the  BB 
incomplete,  and  with  only  one  costal.  Devonian  (Hamilton  Group) ;  North 
America. 

Hadrocrinus  Lyon  {Coronocrinus  Hall  ex  Troost).  Dorsal  cup  extremely 
large,  with  concave  base ;  basals  closely  anchylosed.  Brachials  to  the  fourth 
or  fif th  Order  incorporated  in  the  cup.  Interbrachials  numerous  and  large ; 
no  distinct  anal  plate  in  lower  ranges.  Tegmen  composed  of  innumerable 
small  plates.  Devonian  (Onondaga) ;  Falls  of  the  Ohio,  near  Louisville, 
Kentucky. 

The  type  described  under  tliis  genus  has  not  hitherto  been  well  understood.  It  falls  into 
two  subdivisions,  ditfering  more  strongly  than  Stereocrinus  and  Dolatocrinus  ;  one  (/f.  discus) 
having  few  very  heavy  arms,  and  one  costal ;  the  other  {H.  plenissimus)  witli  numerous  very 
slender  arms,  an^  two  costals. 


Fig.  290. 

Patelliocrinus  lepto- 
-D„„p    dactylus  (Ang.).     8il- 


Family  6.     Calyptocrinidae   Angelin. 

Momcydic.     Lower  brachials  and  interbrachials  forming  an  impmiant  pari  of 
the  dorsal  cup,  which  above  the  base,  is  perfectly  pentamerous.     Plates  of  the  calyx 


192 


ECHINODERMATA— PELMATOZOA 


THYLUM  IV 


usualUj  limited  to  a  definite  mimber.  Radiah  in  contact  all  around.  Arms  resting 
in  compartments  formed  hy  partitions  attached  to  the  tegmen.  Silurian  and 
Devonian. 

Eucalyptocrinus  Goldf.  {Hypanthocrinus  Phill.)  (Figs. 
291,  292).  Calyx  with  a  deep  concavity  at  the  lower  end, 
the  B  forming  the  bottom,  and  the  B  the  sides  of  an 
inverted  cup.  Supplementary  pieces  of  the  calyx  con- 
sisting  of  1  X  2  interbrachials,  and  one  interdistichal ;  the 
latter  of  the  same  form  as  the  interbrachials,  and  nearly 
as  large  as  the  two  upper  ones  combined.  Tegmen 
elongate,  its  upper  part  extended  to  form  a  tube.  It  is 
j  composed  of  five  ranges  of  plates,  of  which  the  two 
middle  ones  are  the  least  regulär  in  their  arrangement, 
and  the  upper  one  closes  the  centre.  Attached  to  the 
outer  walls  of  the  tegmen,  and  extending  to  its  top,  are 
ten  partitions  supported  by  the  interbrachials  and  inter- 
distichals,  which  form  deep,  vertical  compartments  for 
the  reception  of  two  arms  each.  Arms  twenty,  biserial ; 
composed  of  very  narrow  pieces.  Column  round.  Sil- 
urian ;     Gotland,    England    (Wenlock    Limestone),    and 

A  Single  species  occurs 
in  the  Devonian  of  the  Eifel. 

Callicrinus    Ang.    (Fig.    293).      Calyx    flask  -  shaped ; 
concavity    at   the    base   deeper  and  wider   than    in    the 
preceding,    sometimes    involving    not    only    the    radials,    but   parts    of    the 


Fig.  291. 
Eucalyptocrinus     regu 
laris  (Hising.).     Silurian,    -»t        i      a  •         /^-r- 

Gotland.      Crown    with   North  Amcrica  (Niagara  Group), 

arms   removed    from  one  -       — 

ray  in  order  to  sliow  tlie 
niches  in  whicli  they 
repose. 


Fig.  292. 


iri  :    ri  r2  :  iri 
dist.        dist. 


FAicalyptocrinus  rosaceus  (Goläf.).  Devonian;  Gerolstein,  Eifel.  ^/Perfect  crown.  B,  Ciagrammatic  longi- 
tudinal  section  of  the  calyx  (h,  Basais  ;  ri,  Radials  ;  r2,  First  costals  ;  y,  Lower,  and  ö,  upper  piece  of  the  wing- 
like  processes).  C,  Tegmen.  D,  Dorsal  cup  (ri,  Radials  ;  r'-J,  First  costals  ;  (/■,  Intcrnidials  ;  disL,  Distichais  ; 
int.  dist.,  Interbrachials;  r^,  Palmars)  (after  L.  Schultze). 

costals  as  well.     Partitions  for  the  reception  of  the  arms  much  shorter,  ex- 
tending  to   less   than   half    the  height  of  the  arms.      Otherwise  similar  to 


CLASS  III 


CRINOIDEA 


193 


Eucalyptocrinus,  and  sharing  the  same  distribution  in  the  Silurian ;  not  known 
in  the  Devonian. 


Fig.  293. 
Callicnmis  rodatus  (Hising.).     Silurian  ;  Gotlaud.     A,  Crown.     B,  Calyx  showing  the  construction  of  the 
tegmen.      V,  Inner  or  ventral  aspect  of  tlie  ba.se.     D,  Outer  or  dor.sal  aspect  of  the  same.      Natural  size  (after 
Angelin). 

Chicagocrinus  Weller.  Like  Callicrinus,  but  the  primibrachs  (costals) 
reduced  to  a  single  diminutive  plate  in  each  ray.  Silurian ;  North  America 
(Chicago  area). 


Family  7.     Batocrinidae  Waclismuth  and  Springer. 

Monocyclic.     The  lower  brachials  forming  an  important  part  of  the  dorsal  cup. 
Radiais  in  contad  except  at  the  posterior  side,  where  they  are  separated  hy  a  hepta- 
gonal  anal  plate,  followed  hy  three  plates  in 
the  second  ränge.     Base  hexagonal.     Rays 
usually  hranching  hy  equal  hifurcations. 


Subfamily  A.     Periechocrininae. 

Tegmen  composed  of  numerous  small,  un- 
dißerentiated  plates.  Ordovician  to  Lower 
Carboniferous. 

Tanaocrinus  W.  and  Sp.  Interbrachials 
numerous,  indefinitely  arranged  in  de- 
pressed  areas  passing  gradually  into  the 
tegmen,  leaving  brachials  in  ridges  con- 
tinuing  to  the  free  arms ;  posterior  area 
divided  by  median  ridge  of  anal  plates 
resembling  brachials.  Arms  uniserial 
with  ossicles  more  or  less  cuneate,  tend- 
ing  to  interlock  distally ;  branching  be- 
yond  the  calyx.  Calyx  elongate.  Basais 
five.     Column  round,  or  sub-pentagonal. 


o^o 


gfib? 


ÄO^N^O®^ 


^^^;:^^^(D^^9£ß 


of 


Q^ 


Fi( 


BdtocrinHfi  si 


294. 

Carboniferous.    Analysis 


of  calyx  ;  h,  Basals ;  li,  Radials ;  ihr,  Interbi-achials ; 
SX,  supplenieiitary  anal ;  X,  Special  anal  plate 
(after  W.  and  Sp.). 

Ordovician  (Cincinnatian) ;  Ohio. 


Xenocrinus^  S.  A.  Miller.      Basals  four.     Arms  not  branching.     Column 

1  Better  speciraens  obtained  since  the  preparation  of  Wachsmuth  and  Springer's  Monograph 
show  clearly  not  only  that  the  interbrachials  in  this  genus  are  deflnite  plates  with  close  sutures,  but 
VOL.  I  O 


194 


ECHINODERMATA— PELMATOZOA 


PHYLÜM  IV 


quadrangular.      Structure    otherwise    substantially    as    in    the    preceding. 
Ordovician  (Cincinnatian) ;  Ohio. 

Compsocrinus  S.  A.  Miller.  Basais  four.  Arms  simple  or  branching. 
Basais  and  radials  more  evenly  rounded  and  less  excavate  laterally,  but  other- 
wise differing  little  from  Xenocrinus.     Ordovician  (Cincinnatian) ;  Ohio. 

Jcacocrinus  W.  and  Sp.  Interbrachials  few,  definitely  arranged,  not  in 
strongly  depressed  areas,  and  brachials  and  anals  not  in  prominent  ridges. 
First  primibrach  (costal)  quadrangular.  Arms  uniserial,  slender,  unbranched, 
with  cuneate  ossicles  tending  to  interlock  at  the  tips.  Calyx  rather  low  and 
rotund.     Basais  three.     Silurian  ;  Indiana  and  Kentucky. 

Carpocrinus  Müller  (PJioenicocrinus  Austin ;  Abracrimis  d'Orb. ;  Habro- 
crinus,  Pionocrinus,  Lepiocrinus  Ang.)  (Fig.  295).      Calyx  as  in  the  preceding. 

.,,„,.  Arms     simple,     heavy, 

usually  not  exceeding 
ten,  with  very  short, 
wide  ossicles,  slightly 
cuneiform,  the  longer 
face  bearing  two  pin- 
nules,  the  shorter  but 
one.  Silurian  ;Gotland, 
England. 

Desmidocrinus  Ang. 
(Fig.  296).  Like  the 
preceding  but  with  arms 
fifteen  to  twenty,  ossi- 
cles longer  and  quad- 
rangular, bearing  one 
pinnule  to  each  side. 
Silurian  ;  Gotland  and 
England. 

Abacocrinus       Ang. 

(Carolicrinus  Waag.  and  Jahn).     Basais  four.     Calyx  rotund.     Interbrachials 
rather  numerous,  definitely  arranged,  not  in  depressed  areas  ;   brachials  and 
anals  not  in  prominent  ridges.     First  primibrach  hexagonal.     Arms  branch- 
ing, biserial  from  the  calyx  up.     Silurian  ;  Gotland. 
Macarocrinus  Jaekel.      Devonian  ;  Germany. 

Penechocriniis  Austin  (Geocrinus  d'Orb.;  Pyxidocrinus  Müller;  Trochocrimis 
Portlock  ;  Pradocrinus  de  Verneuil).  Basais  three.  Calyx  elongate,  expanding 
to  arm  bases ;  plates  thin  and  long,  usually  with  narrow  median  ridges  along 
the  brachial  series,  which  bifurcate  two  or  three  times  within  the  calyx,  lead- 
ing  to  twenty-five  or  thirty  arms,  which  are  biserial  beyond  the  calyx  and  do 
not  branch  after  becoming  free.  First  primibrach  (costal)  hexagonal.  Inter- 
brachials numerous,  definitely  arranged.     Silurian ;  England  and  Gotland. 

Saccocrinus  Hall.  Like  the  preceding,  but  the  arms  branch  from  about 
twenty  openings  after  becoming  free,  and  are  biserial  both  below  and  above  the 
bifurcations.  Silurian  to  Lower  Carboniferous  (Upper  Burlington) ;  North 
America  and  (?)  Gotland. 


Fig.  295. 

a,  Carpocrinus  comtus  (Ang.).  Silurian ;  Got- 
land. Crown  viewed  from  the  anal  side,  natural 
size.  b,  H.  ornatus  (Ang.).  Tegmen  showing  cover- 
ing  pieces  of  the  ambulacra  (after  Angelin). 


Fig.  296. 

Desmidocrinus 
heterodactylus  (Ang. ). 
Silurian  ;  Gotland. 
Natural  size  (after 
Angelin). 


that  they  do  not  pass  dowii  to  the  basals  in  eitlier  species.  This  leaves  no  character  to  separate  it 
from  the  Batocrinidae,  and  the  present  reviser  agrees  with  Bather  in  placing  it  with  Tanaocrinus 
and  Compsocrinus  as  the  primitive  forms  of  that  faniily. 


CLASS  in  CRINOIDEA  195 

(?)  Beyrichocrinus  Waag.  and  Jahn.     Silurian  ;  Bohemia. 

Gennaeacrinus  W.  and  Sp.  Basais  three.  Calyx  low  and  broad,  strongly 
lobed  at  the  arm  bases  ;  plates  thin  and  highly  ornamented.  First  primibrach 
hexagonal ;  iBr  rather  numerous.  Arm  openings  twenty-five  or  more  ;  arms 
unknown.     Devonian  ;  Indiana  and  New  York. 

Megistocrinus  Owen  and  Shum.  {Tylocrinus  Wood).  Basais  three.  Calyx 
usually  large,  hemispheric,  with  greatest  height  below  the  arm  bases ;  usually 
biit  little  lobed ;  plates  heavy,  smooth  or  ornamented.  Interbrachials 
numerous ;  first  primibrach  hexagonal.  Arms  sixteen  to  twenty,  branching 
in  the  free  State,  biserial  above  and  below  the  bifurcations.  Devonian  to 
Lower  Carboniferous  (Upper  Burlington) ;  North  America. 

Subfamily  B.     Barrandeocrininae. 

Tegmen  narrow  and  rigid.     Arms  permanently  directed  downward  enclosing  the 

mlyx. 

A  highly  specialised  type,  represented  by  a  single  genus,  which,  though  having  a  siniilar 
calyx,  ditfers  so  strongly  in  habitus  from  those  of  the  next  section  that  it  is  better  kept 
separate. 

Barrandeocrinus  Angelin  (Cylicocrinus  S.  A.  Miller).  Basais  three.  Calyx 
rather  elongate,  with  tegmen  nearly  flat.  Interbrachials  few,  definitely 
arranged.  Arms  ten,  heavy,  biserial,  directed  downward  over  the  calyx,  with 
pinnules  opening  outward.     Silurian  ;  Gotland  and  North  America. 

Subfamily  C.     Batocrininae. 

Tegmen  hroad,  well  differentiated  ;  'plaies  large  atid  heavy,  forming  a  rigid  roof. 
Arms  not  branching  heyond  the  calyx;  biserial.  Respiratory  por es  fr equently present. 
First  primibrach  (costal)  usually  quadrangular.  Basais  three  in  all  known  genera. 
Devonian  to  Lower  Carboniferous. 

This  section  flourishes  araid  a  remarkable  local  development  of  Crinoid  life  especially 
characteristic  of  the  Mississippian  area  of  the  United  States.  The  fauna  is  enormously  prolific 
in  numbers  and  variety  in  the  Burlington  and  Keokuk  limestones  of  the  Mississippi  Valley,  but 
alniost  entirely  wanting  in  the  Lower  Carboniferous  of  Great  Britaiu  and  Belgiuni,  and  of 
other  parts  of  the  United  States.     Only  a  few  straggling  species  come  from  the  Devonian. 

§  1.  Anus  at  the  end  of  a  tube. 

a.  Interbrachials  few,  separated  from  tegmen  by  arch  of  brachials. 

Batocrinus  Casseday.  Calyx  biturbinate.  Arms  short,  equidistant.  Anal 
tube  very  long,  central,  extending  beyond  arms.  Kinderhook  to  St.  Louis 
Group;  North  America. 

Eretmocrinus  Lyon  and  Cass.  Like  Batocrinus,  but  arms  paddle-shaped, 
and  anal  tube  short,  eccentric,  tending  to  curve.  Devonian  to  Keokuk 
Group ;  North  America. 

Alloprosallocrinus  Lyon  and  Cass.  Calyx  conical ;  dorsal  cup  almost  flat, 
greatest  height  above  the  arm  bases.  First  primibrach  usually  wanting. 
Approaching  Agaricocrinus  in  shape.  Anal  tube  sub-central ;  arms  unknown. 
Keokuk  limestone  ;  North  America. 

ß.  Interbrachials  few,  usually  separated  from  the  tegmen  except  at  anal  skle. 

Macrocrinus  W.  and  Sp.      Calyx  elongate,  biturbinate  to  subovoid.     Anal 


196 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


tube  rather  large,  extending  beyond  arms.  Arms  twelve  to  sixteen.  Upper 
Burlington  and  Keokuk  Gr. ;  America. 

Dizygocrinus  W.  and  Sp.  Calyx  rotundate.  Anal  tube  rather  small, 
usually  not  extending  beyond  the  arms.  Arms  single  or  double,  from  twelve 
to  twenty  openings.      Upper  Burlington  to  St.  Louis  Group ;  America. 

Eutrochocrinus  W.  and  Sp.  Calyx  wheel-shaped.  Anal  tube  long.  Arms 
short,  eitber  single  or  double  from  twenty  openings.  Upper  Burlington  and 
Keokuk  Group ;  America. 

y.  Interbrachials  few,  sometimes  connected  with  tegmen  all  around. 

Uperocrinus  Meek  and  Worthen  (Lohocrinus  W.  and  Sp.,  Hyperocrinus 
Bather)  (Fig.  297).  Calyx  pyriform.  Anal  tube  large 
and  often  spiniferous.  Arms  short,  single,  often  arranged 
in  groups,  openings  directed  upward.  Upper  Burlington 
and  Keokuk ;  America. 

§  2.  Anus  without  a  tube,  directly  through  tegmen. 
Interbrachials  few,  usually  not  connecting  with  tegmen  except 
at  anal  side. 

Aorocrinus  W.  and  Sp.     Calyx  small,  elongate  to  ro- 

tund  or  biturbinate.  Arms 
rather  strong,  onefrom  each 
opening,  cylindrical.  Teg- 
men plates  not  spiniferous. 
Devonian  to  Burlington ; 
Europe  and  America. 

Coelocrinus  M.  land  W. 
(Sphaerocrinus  M.  and  W. 
non  Roemer).  Similar  to 
preceding  genus,  but  with 
concave  base.  Burlington 
Group ;  America. 

Dorycrinus  Roemer  (Fig. 
298).  Calyx  small  to'large; 
posterior  oral  alone,  or  with 
primary  radial  plates  of 
tegmen,  spiniferous.    Arms 

rather  small,  usually  two  from  each  opening.     Devonian  to  Keokuk  ;  America. 
Agaricocrinus  Hall  (ex  Troost).     Calyx  small  to  large,  hemispherical,  with 

dorsal  side  usually  flat  or  concave,  and  greatest  height  above  the  arm  bases. 

First  primibrach  sometimes   hexagonal.     Arms  ten   to   sixteen,  very  heavy, 

directed  outwards.     Burlington  to  Keokuk  ;  America. 


Fig.  297. 

Uperocrinus  pyriformis 
(Shumard).  Lower  Carbon - 
iferous  ;  Burlington,  Iowa. 
Nat.  size  (after  Meek  and 
Worthen). 


Fig.  298. 

Dorycrinus  quinquelohus  (Hall) 
var.  intermedius(M.  and  W.).  Lower 
Carboniferous  ;  Burlington,  Iowa. 
Calyx  viewed  from  the  anal  side. 
Natural  size  (after  Meek  and  Wor- 
then). 


Family  8.     Actinocrinidae. 

Monocyclic.  Lower  brachials,  with  well-defined  interbrachials  between  them, 
forming  an  important  part  of  the  dorsal  cup.  Radiais  in  contact  except  at  the  anal 
side,  where  they  are  separated  by  a  hexagonal  anal  plate,  followed  by  two  plates  in  the 
second  ränge.  Basais  three,  forming  a  hexagon.  Arms  biserial  in  all  known  genera. 
Rays  usually  branching  by  alternate  bifurcations.  Lower  Carboniferous.  Kinder- 
hook to  Keokuk. 


CLASS  III  CRINOIDEA  197 

This  family  represents  another  line  of  ju-ofuse  crinoidal  development  characteristic  of  the 
Mississippian  area  iu  the  United  States,  parallel  to  tliat  of  the  later  Batocrinidae.  It  maybe 
considered  as  a  direct  branch  from  that  family,  but  sliarply  and  consistently  distinguished 
from  it  by  the  fact  that  the  anal  plate  is  followed  by  two  plates  instead  of  three.  It  was 
sliort  lived,  being  restricted  to  the  lower  part  of  the  Lower  Carboniferous,  where  it  culrainated 
in  large  and  striking  forms,  not  found  outside  of  the  Mississippi  Valley,  Only  two  of  its  genera 
are  certainly  known  to  occur  in  the  approximately  äquivalent  forraation  of  Europe. 

§  1 .   Tegmen  composed  of  well  differentiated  plates,  mth  anus  at  the  end  of  a  tuhe. 
a.  Interbrachials  connecting  with  the  tegmen. 

Amphoracrinus  Austin.  Calyx  lobed,  the  largest  part  above  the  arm  zone  ; 
rays  widely  separated.  Interbrachials  few.  First  primibrachs  usually  quad- 
rangular,  sometimes  hexagonal.  Arms  stout,  either  simple  or  branching, 
biserial  below  and  above  the  bifurcations.  Anal  tube  short,  eccentric.  Oral 
plates  often  strongly  spiniferous.  Anal  plate  exceptionally  followed  by  three 
plates  in  the  second  ränge.  Lower  Carboniferous ;  Waverly  to  Lower  Bur- 
lington Group  in  the  United  States,  and  lower  part  of  the  Mountain  Lime- 
stone in  Britain. 

This  genus  is  a  transition  form  from  the  Batocrinidae,  in  whieh  the  Actinocrinoid  structute 
of  the  anal  side  has  not  become  constant.  In  some  species  the  middle  plate  of  the  second  row 
has  not  been  entirely  eliminated,  but  occasionally  appears  in  diminished  size,  and  scarcely 
touching  the  anal  plate.  This  is  consistent  with  its  geological  position  as  one  of  the  earliest 
of  its  family,  and  one  of  the  first  to  disappear. 

Admocrinus  Miller  {Amphora  Cumb.;  Phillipsocrinus  M'Coy;  Blairocrinus 
S.  A.  Miller)  (Fig.  299,1)).  Calyx  lobed,  rays  widely  separated;  largest  part 
below  arm  zone.  Interbrachials  numerous.  First  primibrachs  usually 
hexagonal.  Rays  within  the  calyx  bifurcating  alternately  from  every  second 
or  third  plate  above  the  first.  Arms  either  simple  from  the  calyx,  or 
branching,  and  biserial  below  as  well  as  above  the  bifurcations.  Anal  tube 
long,  central.  Lower  Carboniferous;  Lower  Burlington  to  Keokuk,  in  the 
United  States,  and  Mountain  Limestone  of  Britain  and  Belgium. 

Steganocrinus  M.  and  W.  {Sampsonocrinus  M.  and  G.).  Calyx  similar  to  that 
of  Admocrinus,  but  relatively  lower,  and  having  the  rays  produced  into  one 
{S.  sculptus)  or  two  (S.  pentagonus)  tubulär  extensions  giving  off  pinnulate  arms 
alternately  at  the  sides.  Anal  tube  small.  Lower  Carboniferous  (Lower  and 
Upper  Burlington) ;  North  America. 

ß.  Interbrachials  not  connecting  with  tegmen. 

Cactocrinus  W.  and  Sp.  (Fig.  299,  ^,  B).  Calyx  not  lobed.  Arms  usually 
strong,  twenty  to  forty,  unbranched,  about  equidistant,  given  off  in  a  more  or 
less  continuous  ring,  and  directed  upward ;  bifurcations  beyond  the  costals 
from  every  successive  brachial.  Anal  tube  long,  central.  Lower  Carboni- 
ferous (Kinderhook  to  Lower  Burlington);  North  America,  (?)  Belgium. 

Teliocrinus  W.  and  Sp.  Similar  to  the  last,  but  arms  more  slender  and 
numerous,  usually  sixty  or  more,  their  lower  portions  directed  outward,  and 
forming  a  broad  continuous  rim.  Lower  Carboniferous  (Upper  Burlington) ; 
North  America. 

§  2.  Tegmen  of  undifferentiated  plates.  Anus  directly  through  the  tegmen,  without 
a  tube. 

Physetocrinus  W.  and  Sp.  (Fig.  299,  C).  Interbrachials  connecting  with 
tegmen.     Calyx  rotund,  lobed,  with  arms  in  groups,  stout ;  tegmen  rounded 


198 


ECHINODEKMATA— PELMATOZOA 


PHYLUM  IV 


and  elevated  ;  anus  eccentric.  All  bifurcations  beyond  costals  given  off  from 
every  alternate  brachial.  Lovver  Carboniferous  (Lower  and  Upper  Burlington) ; 
North  America. 

Strotocrinus    M.    and    W.       Interbrachials    not    connecting    with    tegmen. 


""^-^.y 


%y 


\%    dßo 


t^ 


■fßS      ^       -^^» 


ö3;«ig 


& 


m 


Fio.  299. 

A,  Cactocrinus  proboscidialis  (Hall).  Lower  Carboniferous  ;  Burlington,  Iowa.  Calyx  witli  fractured 
tegmen,  showing  the  subtegminal  ambulacral  skeleton,  and  the  convoluted  digestive  organ.  B,  Enlarged 
portion  of  the  ambulacral  skeleton,  C,  Natural  cast  of  tegmen  of  Phy^ietocrinus,  with  impressions  of  food- 
grooves  (a),  condncting  from  the  arms  to  the  mouth  (o) ;  an,  Anus.  D,  Diagraui  of  Äctinorrinus  (after  W. 
and  Sp.). 

Calyx  not  lobed  ;  rays  bifurcating  on  alternate  brachials  from  distichals  up, 
and  extended  into  a  broad,  flanging  rim,  as  in  TeMocrinus,  but  more 
pronounced.  Arms  very  numerous  and  slender.  Tegmen  low,  sometimes  flat 
or  concave,  composed  of  innumerable  small  pieces  ;  anus  eccentric.  Lower 
Carboniferous  (Upper  Burlington) ;  North  America. 


Family  9.     Platycrinidae  Roemer. 

Monocydic.  Brachials  and  interbrachials  usually  but  slightly  represented  in  the 
dorsal  citp  :  the  lower  brachials  taking  more  or  less  the  form  of  arm  plates,  but  being 
strongly  connected^  either  with  the  solid  tegmen  by  modified  covering  plates  and  strong 
interambulacrals,  or  with  the  cup  by  large  interbrachials  which  are  usually  more  or 
less  interambulacral  in  position.  Radiols  in  contact  all  around,  there  being  no 
special  anal  plate.  Basais  forming  a  pentagon ;  three,  unequal,  and  frequenÜy 
anchylosed.     Silurian  to  Carboniferous. 


CLASR  TU 


CRINOIDEA 


199 


§  1.  Rays  with  two  or  more  primilrrachs  (costals). 

Coccocrinus  Job.  Müller.  The  simplest  form  of  the  Camerata,  the  calyx 
consisting  only  of  three  basals,  five  radials,  2x5  costals,  five  interbrachials  and 
five  orals.  Calyx  small,  rotund ;  basals  and  radials  forming  almost  the  entire 
dorsal  cup.  Tegmen  almost  completely  occupied  by  five  large,  triangulär, 
symmetrical  orals,  forming  a  pyramid.  Anal  opening  in  the  interradio- 
oral  suture.  Arms  delicate,  branching  once,  uniserial  with  cuneate  joints. 
Column  round.     Silurian  ;  North  America.     Devonian  ;  Eifel. 

Culicocrinus  Joh.  Müller.  Transitional  between  Coccocrinus  and  Platycrinus ; 
generally  similar  to  the  former.  Orals  asymmetrical.  Arms  heavy,  biserial. 
Column  round.     Middle  Devonian  ;  Eifel. 

Hapalocrinus  Jaekel  em.  Bather  {Agriocrinus,  Thallocrinus  and  Clematocrinus 
Jaekel).  Orals  small ;  interambulacra  visible.  Arms  uniserial,  with  cuneate 
joints  ;  branching  once  or  twice.  Column  round,  with  strong  cirri.  Silurian  ; 
England,  Australia,  North  America.     Devonian ;  Germany. 

Cordylocrinus  Angelin.  Tegmen  composed  of  numerous  plates.  Arms 
uniserial,  or  slightly  interlocking.  Column  round,  with  long  cirri.  Silurian ; 
Gotland.     Devonian  ;  North  America. 

§  2,  Eays  with  only  one  primibrach  (costal).  Orals  occupying  but  a  small  part  of 
the  tegmen,  asymmetrical ;  ambulacral  plates  well  defined. 

Marsipocrinus  Bather  {pro  Marsupiocrinus  Phill.,  nm  Blv.).  (Syn.  Cypellocrinus 
vel  Cupellaecrinus  Shumard,  ex  Troost,  non  Steininger.)  Brachials  to  axillary 
distichal  usually  incorporated  in  cup.  Arms  biserial,  ten  or  twenty.  Column 
round.     Axial  canal  large.     Silurian ;  England,  Gotland,  North  America. 


Fig.  300. 
Platycrinus  suhspinomn  (Hall).  Lower  Carbonifer- 
ous;  Burlington  Group,  Iowa.  Analysis  of  dorsal 
cup,  omitting  anal  Interray.  h,  Basals  ;  R,  radials  ; 
I,  Costals;  ir,  Interbrachials  (after  Wachsmuth 
and  Springer). 


Fio.  301. 
Platycri iius  triginti(lactyliu<< 
(Austin).    Lower  Carbonifer- 
ous ;  Tournay,  Belgiuni  (re- 
stored,  after  de  Koninck). 


Platycrinus  Miller  {Centrocrinus,  Pleurocrinus  Austin;  Edwardsocrinus  d'Orb.) 
(Figs.  300,  301).  Calyx  rotund.  Radials  large  with  crescent-shaped  facets. 
First  interbrachials  at  the  level  of  the  arm  bases ;  consisting  of  three  plates 
horizontally  arranged,  usually  partly  interambulacral,  but  sometimes  succeeded 
by  one  or  more  ranges  incorporating  the  distichals ;  plates  of  anal  interradius 
usually  more  numerous  than  those  of  the  other  sides.  Orals  usually  large, 
asymmetrical,  occupying  but  a  small  part  of  the  tegmen.      Ambulacra  rigid, 


200 


ECHINODERMATA— PELMATOZOA 


PHYLUM  XV 


and  incorporated  into  the  tegmeri.  Anus  either  eccentric,  or  at  the  end  of  a 
thick,  usually  short  tube.  Arms  branching  once  to  three  times,  uniserial  in 
the  lower  parts,  but  becoming  biserial  distally.  Column  elliptical  and  twisted  ; 
the  axes  of  the  upper  and  lower  surfaces  of  the  individual  segments  being  at 
a  slight  angle  with  one  another;  central  canal  very  minute;  strong  cirri 
toward  distal  end.  Rare  in  Devonian ;  abundant  in  Lower  Carbonif erous  of 
England,  Belgium  and  North  America  (Hamilton  to  St.  Louis  Groups). 

Brahmacrinus  Sollas.  Like  Platycrinus,  but  radials  relatively  smaller,  and 
lower  brachials  larger,  and  incorporated  in  dorsal  cup  to  the  height  of  the 
second  distichals.     Lower  Carboniferous  ;  England. 

Eudadocrinus  M.  and  W.  Calyx  like  Platycrinus,  but  with  rays  produced 
into  one  or  two  main  rami,  roofed  with  rigid  covering  plates,  forming  tubulär 
extensions  of  the  calyx,  giving  off  at  alternate  sides  biserial,  pinnuliferous 
arms.  An  extreme  development  of  the  family  type,  but  not  the  latest  in 
time.     Lower  Carboniferous  (Kinderhook  to  Keokuk) ;  North  America. 

Family  10.     Hexacrinidae   Wachsmuth  and  Springer. 

Monocydic.  Radials  in  contaä  except  at  the  posterior  side,  where  they  are 
separated  hy  an  anal  plate.  Basais  three,  or  two,  forming  a  hexagon.  Strudure 
otherwise  as  in  the  Platycrinidae.     Devonian  to  Lower  Carboniferous. 

§  1.  Basais  three. 

Hexacrinus  Austin  (Fig.  302).  Costals  two,  united  by  syzygy,  or  one. 
Rays  usually  in  two  main  trunks,  bearing  uniserial  pinnulate  arms  on  one  or 


Fig.  302. 


Hexacrinus  elongatus  (Goldf.).     Devonian  ;  Pehn,  Eifel.     a,  Calyx  seen  from  one  side  ;  /;,  Aspect  of  summit ; 
c,  Analysis  of  calyx  and  arms  ;    d,  e,  Column  of //,  spinosus  (Müll.)  (after  L.  Schnitze). 

both  sides  at  intervals.  Tegmen  as  in  Platycrinus.  Column  round,  with  small 
axial  opening.  Devonian.  Represented  by  numerous  species  in  England, 
Belgium,  and  the  Eifel,  but  by  only  a  few  in  North  America. 

Arthracantha  Williams  (Histricrinus  Binde).  Calyx  as  in  Hexacrinus,  but 
the  plates  covered  with  movable  spines  borne  on  tubercles.  Arms  dichotomous, 
biserial.     Stern  circular.      Devonian  :  New  York  and  Canada. 


CLASS  III 


CRINOIDEA 


201 


§  2.  Basais  two. 

Dichocrinus  Münster  (Cotyledonocrinus  Lyon  and  Cass.).  Costals  two, 
usually  united  by  syzygy,  as  are  also  the  first  two  brachials  of  each  order, 
giving  the  appearance  of  a  single  plate.  Arms  biserial,  branching  once  to 
three  times ;  occasionally  pendent.  Stern  round.  Lower  Carboniferous ; 
Belgium,  Great  Britain,  North  America  (Kinderhook  to  Kaskaskia). 

Camptocrinus  W.  and  Sp.  Like  Dichocrinus  except  in  the  stem,  which  is 
concavo-convex  in  section,  as  in  Herpetocrinus,  tending  to  coil  around  the  crown. 
Lower  Carboniferous  (Burlington  to  St.  Louis) ;  North  America. 

Talarocrinus  W.  and  Sp.  Costal  one,  small,  trigonal,  sometimes  hidden 
by  the  distichals.  Calyx  plates  massive ;  anal  resembling  anterior  radial  in 
form  and  size.  Column  round.  Lower  Carboniferous  (St.  Louis  to  Kaskaskia) ; 
North  America. 

Pterotocrinus  Lyon  and  Cass.  (Asterocrinus  Lyon  non  Münster).  A  re- 
markable  modification  of  Talarocrinus.  Brachials  up  to  third  order  incorporated 
into  dorsal  cup.  Anal  plate  much  smaller  than  the  radials.  The  axillary 
first  ambulacral  produced  into  large  wing-like  processes,  stretched  out  from 
the  tegmen.  Lower  Car- 
boniferous (Kaskaskia)  ; 
North  America. 


Family  11.     Acrocrinidae 

Waclismutli  and  Si^ringer. 

Monocyclic.  Basais  separ- 
ated  from  radials  by  a  large 
bell  of  accessory  pieces.  Badials 
in  contact  except  at  the  posterior 
side,  where  they  are  separated 
by  an  anal  plate,  Structure 
otherwise  as  in  the  Hexa- 
crinidae.  Lower  Carboni- 
ferous. 


o, 


Q 


0 
O 


O  9ä<o" 


oö8 


8oRo 


Acrocrinus  Yandell  (Fig. 
303).  Basais  two,  forming 
a  hexagon.  Calyx  as  in 
Dichocrinus  with  intercala- 
tion  of  several  circlets  (u^) 
to  twenty)  of  supplementary 
plates,  those  immediately 
above  the  basals  being  the 
smallest  and  latest  formed. 

Costals  small,  trigonal.  Arms  two  to  four  to  the  ray,  biserial,  either  erect 
or  pendent.  Column  round.  Lower  Carboniferous.  The  last  survivor  of 
the  Camerata  (Burlington  to  Coal  Measures),  and  known  chiefly  in  North 
America  but  reported  recently  from  England. 


/  R  N 

Fio.  303. 
Acrocrinus  sp.     Lower    Carboniferous.      /),  Basals;    R,  lladials 


I,  Costals ;  x,  Special  anal  plate. 
ary  plates  (after  W.  and  Sp.). 


tVU  the  others  are  Supplement- 


202  ECHINODERMATA— PELMATOZOA  phylum  iv 

Order  2.     PLBXIBILIA   Zittel. 

(  =  Articulata  W.  and  Sp.  non  Müller). 

Crinoidea  in  which  the  lower  brachials  are  incorporated  in  the  dorsal  cup,  either 
hy  lateral  union,  hy  interhrachials,  or  hy  a  finely  plated  sJcin,  hut  never  rigidly. 
Tegmen  flexible,  with  amhulacra  well  defined,  roofed  with  movaole  covering  plates  ; 
mouth  supra-tegminal  and  open.  Arms  non-pinnulate,  with  a  wide  and  shallow 
ventral  groove.  Base  dicydic ;  infrabasals  three,  unequal,  rarely  iindivided,  some- 
times  greatly  reduced  or  atrophied ;  often  fused  with  top  columnal.  Radiais  and 
brachials  united  by  modified  muscular  articulation,  usually  without  transverse  ridge, 
accompanied  by  loose  suture  between  other  plates,  producing  a  flexible  calyx  admitting 
motion  between  apposed  faces  of  the  plates.  Orals  small,  posterior  one  much  the 
largest,  with  the  food  grooves  passing  between  them  to  the  mouth  ;  they  are  more  or 
less  surrounded  by  perisome,  which  often  passes  down  between  the  rays.  Stern  round  ; 
proximal  columnals  usually  very  short,  frequently  wider  than  the  others  and  forming  a 
Gonical  expansion  next  to  the  calyx.     Ordovician  to  Carboniferous. 

The  calyx  and  arm  plates  in  this  group  are  usually  thick  and  relatively  short, 
with  a  muscular  or  loose  ligamentous  articulation,  which  admits  of  much  mobility 
upon  one  another.  The  combination  of  massiveness  with  flexibility  is  a  strong 
distinctive  character.  The  union  between  brachials  is  frequently  marked  exteriorly 
by  arcuate  sutures,  produced  by  a  downward  projection  of  the  outer  proximal  edge  of 
the  plates  into  a  corresponding  depression  on  the  distal  edge  of  those  preceding ;  this 
extends  but  little  below  the  surface,  the  sutures  beneath  being  perfectly  straight.  By 
contraction  in  fossilising  the  projecting  processes  are  frequently  fractured,  giving  rise 
to  an  erroneous  appearance  of  "patelloid  plates." 

Owing  to  the  fact  that  in  most  of  the  genera  the  rays  are  more  or  less  continuous 
from  the  radials  up,  with  no  well-defined  zone  of  demarcation  between  calyx  and 
arms,  there  is  a  general  similarity  of  type  which  renders  the  subdivisions  less  apparent 
than  in  the  Camerata.  The  most  prominent  modification  of  the  general  type  relates 
to  the  structure  of  the  posterior  interradius,  upon  which  two  well-defined  divisions 
may  be  recognised  :  (1)  the  strong  anal  side,  in  which  the  anal  plates,  when  present, 
are  partly  or  whoUy  incorporated  in  the  calyx  wall ;  (2)  the  weak  anal  side,  in  which 
the  anal  plates  are  separated  from  adjacent  brachials  at  one  or  both  sides  by  a  pliant 
integument,  and  tend  to  form  a  flexible  series  supporting  the  anal  tube,  which  is 
a  mere  extrusion  of  the  pliant  perisome  of  the  tegmen.  The  second  of  these 
structures  is  analogous  to  that  in  the  larval  stage  of  the  living  Crinoids,  is  the  most 
generalised,  and  was  the  most  persistent — appearing  in  the  Ordovician,  and  ending 
with  the  culmination  of  this  group  in  the  Kaskaskia,  or  possibly  Goal  Measures.  The 
first  is  more  specialised,  and  ranges  from  the  Silurian  to  the  Warsaw.  Within  it  modifi- 
cations  in  the  size  and  position  of  the  infrabasals,  and  in  the  general  habitus,  afford 
ground  for  family  divisions,  which  shade  into  one  another  to  some  extent. 

Among  the  genera  of  each  family  there  may  be  observed  a  migration  of  the 
radianal,  from  a  primitive  position  directly  underneath  the  right  posterior  radial  (as 
if  the  radial  were  transversely  bisected)  in  the  older  formations  (Ordovician  and  some 
Silurian),  to  an  oblique  position  to  the  lower  left  of  the  radial  (some  Silurian  and 
Devonian),  and  then  to  complete  elimination  in  the  Carboniferous.  Modifications  in 
the  number  of  primibrachs,  by  increase  from  two  to  three  or  more,  were  also  to  some 
extent  coincident  with  these  changes.  The  structure  of  the  base  remains  remarkably 
constant,  the  proximal  circlet  consisting  of  three  unequal  infrabasals,  which  are 
exceptionally  fused  to  an  undivided  disk,  and  in  certain  genera  tend  to  disappear  by 
resorption. 


I 


ci^Ass  III  CRINOIDEA  203 


I 


A.  Anal  plates,  when  present,  partly  or  wholly  incorpm'ated  in  the 
calyx. 

Suborder  1.    SAGENOCRINOIDEA. 

Family  1.     Lecanocrinidae   Springer. 

Infrabasals  abutting  on  dorsal  side  of  basals,  more  or  less  ered,  and  taking 
pari  in  the  calyx  wall  Crown  usually  small,  short,  rotund,  with  arms  abutting, 
frequently  interlocking,  and  closely  infolding  at  the  distal  ends.  Silurian  to  Lower 
Carboniferous. 

a.  Rays  in  contact  except  at  the  posterior  side,  where  anal  x  separates  radials,  toucliing 
posterior  basal.     No  iBr  in  other  areas. 

Lecanocrinus  Hall  {Cyrtidocrinus  Ang.)  (Fig.  304).  Arms  dichotomous, 
flat,  interlocking.  RA  rhombic,  obliquely  below  r.post.R.  Anal  x  alone. 
IBr  two  (exceptionally  one).  Silurian  to  Devon- 
ian;  North  America,  Gotland,  England. 

Mespilocrinus  Koninck  and  Lehon.  No  RA. 
Anal  X  alone,  or  followed  by  a  triangulär  plate. 
Arms  dichotomous,  usually  rounded,  with  dex- 
trose  twist.  IBr  two.  Lower  Carboniferous 
(Kinderhook  to  Upper  Burlington)  ;  Belgium, 
England  and  Mississippian  area.  North  America. 

h.  Rays  above  radials  partly  or  wholly  separated  all  FiGr7o4 

around,  by  *5r  or  perisome.     Anal  «  usually  between  pos-       ^  .       , .  '.      .\        „.,    . 

terior  radials,  touohing  basal  (exception,  SipUroainJ).       o'tSTS^^TTn Ä  thTS 

side,  flgiire  reversed  (after  Angelin). 

Homalocrinus  Ang.  Infrabasals  very  large, 
enveloping  basals,  and  sometimes  radials.  Arms  heterotomous,  with  ten 
main  trunks,  bearing  ramules.  Rays  abutting  above  interbrachials,  peri- 
some  not  exposed  interradially.  Anal  x,  and  large  iBr  in  other  areas, 
followed  by  others.  RA  under  r.post.R.  between  BB.  IBr  two.  Silurian ; 
Gotland,  England. 

Calpiocrinus  Ang.  Like  the  preceding,  but  the  rays  have  twenty  main 
trunks  bearing  ramules,  and  there  is  no  RA.     Silurian  ;  Gotland. 

These  two  genera  are  remarkably  specialised  in  the  enormous  overgrowth 
of  the  infrabasals,  which  envelop,  and  sometimes  entirely  conceal,  both  basals 
and  radials,  a  fact  which  has  made  them  heretofore  generally  misunderstood. 

Cholocrinus  Springer.  IBB  not  enveloping  BB.  Arms  heterotomous, 
with  ten  main  trunks  bearing  irregularly  branching  ramules.  Rays  not 
abutting,  divergent,  not  closely  infolding;  no  regulär  iBr,  areas  filled  with 
perisome.  Anal  x  followed  by  perisome.  RA  rhombic,  obliquely  below 
r.post.R.  IBr  two.  Rays  unequally  developed,  the  two  antero-lateral  ones 
being  dwarfed.     Type,  Forbesiocrinus  obesus  Ang.     Silurian  ;  Gotland. 

Anisocrinus  Ang.  Arms  dichotomous.  Rays  abutting  above  iBr,  perisome 
not  exposed.  Anal  x  alone,  or  with  others  following ;  iBr  few,  one  large, 
alone,  or  followed  by  others.  RA  more  or  less  under  r.post.R,  above  line 
of  BB.    IBr  two.    Silurian ;  Gotland,  and  North  America  (Western  Niagara). 

Pycnosaccus  Ang.  (Oncocrinus  Bather).  Arms  dichotomous.  Rays  not 
abutting;  no  regulär  iBr,  areas  wide,  filled  with  perisome.  Radial  facets 
much  less  than  the  width  of  R.      Anal  x  alone,  followed  by  perisome.     JtA 


204  ECHINODERMATA— PELMATOZOA  phylum  iv 

rhombic,   obliquely  below  r.post.R.      IBr  oiie  to  four.      Silurian ;   Gotland, 
England,  and  North  America  (Niagara  of  western  area  and  of  New  York). 

Nipterocriniis  Wachsmuth,  in  Meek  and  Worthen.  Similar  to  Pycmsaccus, 
but  without  BA  or  anal  x,  and  with  infrabasals  fused  to  one.  The  last 
survivor  of  this  family.  Lower  Burlington  to  Keokuk ;  Mississippian  area, 
North  America. 

Family  2.     Sagenocrinidae  Springer. 

Infrabasals  ahutting  on  dorsal  side  of  basals,  low  and  flat,  taking  Utile  part  in 
calyx  wall.  Crown  usually  large,  elongate,  expaiiding  above  the  radials.  Rays 
above  radials  partly  or  wJiolly  separated  all  around.  Silurian  to  Lower 
Carboniferous. 

Temnocrinus  Springer.  Arms  dichotomous.  Anals  and  iBr  only  in  lower 
part  of  interradial  areas ;  anals  more  than  one  abreast.  BA  in  form  of  B 
under  r.post.R.  Anal  x  separating  BB  and  touching  post.B.  IBr  two. 
Type,  Taxocrinus  tuberculatus  Miller.     Silurian  ;  England,  (?)  North  America. 

Meristocrinus  Springer.  Similar  to  Temnocrinus,  but  with  anal  x  followed 
by  other  plates  in  series,  and  IBr  three.  Type,  Taxocrinus  loveni  Angelin. 
Silurian ;  Gotland. 

Sagenocrinus  Austin.  Arms  dichotomous.  Anal  and  iBr  areas  filled  with 
solid  plates.  BA  obliquely  below  r.post.R,  usually  between  BB,  and  not 
touching  r.ant.R.  IBr  two.  Silurian ;  England,  Gotland,  and  North 
America  (Western  Niagara). 

Lithocrinus  W.  and  Sp.  (Forbesiocrinus  Ang.  non  Kon.).  No  BA.  Arms 
heterotomous,  with  ten  main  trunks  bearing  branching  ramules.  iBr  well 
developed  in  lower  part  of  areas.  IBr  two.  Type,  Forbesiocrinus  divaricatus 
Ang.     Silurian;  Gotland. 

Forbesiocrinus  Koninck  and  Lehon.  No  BA.  Arms  dichotomous.  iBr 
usually  numerous,  Alling  the  areas  with  solid  plates.  IBr  three,  except  in 
F.  agassizi,  which  has  two.  The  culmination  of  this  family.  Lower  Carboni- 
ferous (Lower  Burlington  to  Warsaw) ;  Belgium.  Also  Mississippian  area, 
North  America. 

Family  3.     Ichthyocrinidae  Wachsmuth  and  Springer  (restr.). 

Infrabasals  wholly  witliin  the  ring  of  basals,  concealed  by  the  column, 
sometimes  disappearing  by  resorption.  Crown  usually  elongate, 
expanding  above  radials,  but  often  infolding  distally.  Arms 
usually  closely  abutting  or  interlocking.  Silurian  to  Lower 
Carboniferous. 

a.  Rays  in  contact  except  between  posterior  radials  when  separated 
by  anal  x. 

Ichthyocrinus   Conrad    (Fig.    305).       Arms    dichotomous, 

Fig.  305.  closely  interlocking,  and  infolding.     BA  in  form  of  B  under 

Ichthyocrinus  laevis  r.post.R.     No  anal,  üosterior  basal  not  difFerentiated.     IBr 

crown.  Silurian (Xia-   two.     Silurian ;  Gotland,  England  and  North  America  (New 

port,  New' York (after  York  and  Western  Niagara  area). 

^^^^^-  Clidochirus    Ang.       Similar    to    Ichthyocrinus,    but    with 

posterior  basal  difFerentiated,  supporting  anal  x  alone,  or  followed  by  others. 


CLASS  III  CRINOIDEA  205 

Silurian  ;  Gotland.     Silurian  to  Devonian  (Niagara,  Manlius,  Helderbergian) ; 
North  America. 

Metichthyocrinus  Springer.  No  RA.  No  anal ;  posterior  basal  not  differ- 
entiated.  Crown  rotund.  Arms  dichotomous,  interlocking  and  infolding. 
IBr  two.  Type,  Ichthyocr.  tiaraeformis  Hall  ex  Troost  MS.  Lower  Carbon- 
iferous  (Kinderhook  to  Lower  Burlington) ;  Mississippian  area ;  North 
America. 

b.     Rays  above  radials  partly  or  wholly  separated  all  around  ;  posterior  radials  separated 
by  anal  x  when  present, 

Euryocrinus  Phillips.  No  RA.  Arms  dichotomous.  Anal  x  followed  by 
others  in  a  single  series.  iBr  few,  usually  in  single  series.  IBr  three.  Lower 
Carboniferous ;  England.     Devonian  to  Lower  Burlington  ;  North  America. 

Amphicrinus  Springer.  Similar  to  Euryocrinus,  but  with  iBr  numerous,  in 
more  than  one  series,  and  primibrachs  two.     Lower  Carboniferous ;  Scotland. 

Dadylocrinus  Quenst.  (Dimerocrinus  Pacht  non  Phillips).  No  RA.  Crown 
elongate,  expanding  from  RR  up.  Arms  heterotomous,  with  twenty  main 
trunks  bearing  ramules.  iBr  few  or  absent.  Anal  x  followed  by  others  in 
more  than  one  series,  suturally  connected  at  the  sides.  IBr  two.  Devonian ; 
Russia,  Belgium. 

Synerocrinus  Jaekel  {Forbesiocrinus  Trautschold  non  de  Kon.).  Similar  to 
Dadylocrinus,  but  with  anal  x  followed  by  others  in  series  tending  to  form  a 
tube  (transition  toward  Taxocrinidae).  Crown  more  rotund  in  young 
individuals.     Lower  Carboniferous ;  Bergkalk  near  Moscow,  Russia. 

Wachsmutliicrinus  Springer.  Similar  to  Dadylocrinus,  but  with  no  anal 
plate,  posterior  basal  not  difFerentiated.  The  last  survivor  of  this  family  in 
America.  Type,  Forbesiocrinus  thiemei  Hall.  Lower  Carboniferous,  Kinder- 
hook to  Upper  Burlington  ;  Mississippian  area ;  North  America. 

B.  AU  anal  plates  sejparated  by  perisome  from  adjacent  brachials  at  one  or  both 
sides,  tending  to  form  a  tubulär  series,  from  posterior  basal  up. 

Suborder  2.    TAXOCRINOIDEA. 

Family  4.     Taxocrinidae   Bather  emend.  Springer. 

Infrabasals  usually  abutting  on  dorsal  side  of  basals,  but  low,  taking  Utile  part 
in  the  calyx  wall.  Crown  usually  elongate,  with  arms  divergent,  and  not  abutting 
above  interbrachial  areas.  Interbrachials  present  all  around.  Ordovician  to  Lower 
Carboniferous. 

Protaxocrinus  Springer  (Taxocrinus  Ang.  pars ;  Lecanocrinus  Billings).  Arms 
dichotomous.  RA  in  form  of  R,  below  r.post.R.  iBr  few.  IBr  two.  Type, 
Taxocrinus  ovalis  Ang.  Ordovician  to  Silurian;  Gotland,  Canada  and  the 
United  States.     The  geologically  earliest  known  genus  of  the  Flexibilia. 

Gnorimocrinus  W.  and  Sp.  (Taxocrinus  Ang.  pars).  RA  rhombic,  obliquely 
below  r.post.R.  iBr  few.  IBr  two  (or  three).  Type,  Taxocrinus  expansus 
Ang.  Silurian;  Gotland  and  North  America,  western  Niagara  area.  (?) 
Devonian ;  Belgium. 

Eutaxocrinus  Springer.  No  RA.  iBr  variable.  IBr  two.  Type,  Taxo- 
crinus affinis  Müller.  Silurian  and  Devonian  to  basal  j^art  of  Lower  Carboni- 
ferous (Kinderhook) ;  Gotland,  Germany,  North  America. 


206 


ECHINODERMATA— PELMATOZOA 


PHYLÜM  IV 


Taxocrinus  interviedius 
W.  and  Sp.,  showing 
tegmen,  Avith  ambnlacra, 
oraLs  and  open  mouth  be- 
tween  them  (after  Wachs- 
muth  and  Springer). 


Taxocrinus  Phillips  {Isocrinus  Phill.,  7ion  von  Meyer;  Cladocrinus  Austin  7ion 
Ang. ;  Euryalecrinus  Austin).     (Figs.  306,  307.)     Like  Eutaxocrinus,  but  with 

primibrachs  three.      De- 

vonian    to    summit    of 

Lower      Carboniferous ; 

England,    Belgium    and 

North  America. 

Parichthyocrinus 

Springer.     No  BA.    iBr 

few.     IBr  three.     Eays 

closely   abutting    above 

iBr;    arms  interlocking 

and    infolding    distally. 

Has     the     habitus     of 

Ichthyocrinus,  but  with 
the  tube-like  anal  series  of  the  Taxocrinidae 
well  developed.  Lower  Carboniferous ; 
Upper  Burlington  and  Keokuk  ;  (?)  Goal 
Measures  ;  Mississippian  area.  North  Amer- 
ica. Type,  Ichthyocrinus  nobilis  (W.  and  Sp.). 
Onychocrinus  Lyon  and  Cass.  {Oligocrinus 
Springer).  Arms  heterotomous.  Rays 
widely  divergent,  produced  into  ten  large, 
rounded  main  trunks,  bearing  ramules.  No 
EA.  iBr  few  or  numerous.  IBr  three  to 
six,  or  more.  Lower  Carboniferous  (Lower 
Burlington  to  Kaskaskia)  ;  Mississippian 
area,  North  America. 

This  is  the  culmination  and  most  ex- 
travagant development  of  the  Taxocrinoid 
type.  With  the  exception  of  an  imperfectly  known  species,  probably  of 
this  family,  from  the  Lower  Coal  Measures,  this  and  a  depauperate  species 
of  Taxocrinus  are  the  last  survivors  of  the  Flexibilia. 


Fig.  307. 

Taxocrinus  colletti  White.  Perfect  crown. 
Lower  Carboniferous  ;  Crawfordsville,  Ind. 
Usually  known  in  collections  as  T.  meeki,  or 
T.  multibracMahis  (F.  Si)ringer,  original). 


Incertae  sedis. 


Edriocrinus  Hall.  Superficially  resembles  Holopus,  and  its  position  is 
doubtful.  Has  broad  branching  arms,  with  shallow  ventral  groove,  short 
brachials,  and  no  pinnules.  No  stem ;  basals  fused  into  a  rounded  conical 
mass,  attached  by  a  flattened  surface  when  young,  free  in  the  adult.  Radiais 
five,  with  anal  plate  in  same  ränge.  Lower  Devonian  (Helderbergian, 
Oriskany) ;  New  York,  Maryland,  Tennessee. 

Caleidocrinus  Waagen  and  Jahn.  Probably  an  Inadunate  Crinoid,  with 
anal  side  not  difFerentiated  in  dorsal  cup.     Silurian  ;  Bohemia. 

Bhopalocrinus  W.  and  Sp.  Founded  on  a  unique  specimen  described  as 
Taxocrinus  gracilis  Schnitze,  but  does  not  belong  to  this  group.  It  has  a 
strongly  plated  anal  tube  reaching  to  height  of  the  arms,  and  might  be 
described  as  a  dicyclic  Synbathocrinoid,  wdth  some  interbrachial  plates. 
Middle  Devonian ;  Eifel. 


CLASS  III  CRINOIDEA  207 

Order  3.     INADUNATA  Wachsmuth  and  Springer. 

Crinoidea  in  which  the  arms  are  free  ahove  the  radials ;  dorsal  cup  limited  to 
radials,  hasals,  in/rabasals  when  present,  and  anal  plates  ;  no  interradials  oi'  inier- 
hrachials  except  at  the  posterior  (anal)  side,  and  brachials  never  normally  incorporated 
in  the  cup.     All  plates  of  the  cup  united  hy  dose  suture.     Mouth  suh-tegminal. 

Suborder  1.     LARVIFORMIA  Wachsmuth  and  Springer. 

(Haplocrinacea  Neumayr  ;  Larvata  Jaekel  pars). 

Monocyclic  {except  Cupressocrinus).  Calyx  consisting  only  of  hasals  {with  or 
without  infrahasals),  radials,  and  orals,  without  anal  plates,  and  usually  without 
visible  ambulacra.  All  plates  immovably  united  hy  dose  suture.  Arms  non- 
pinnulate,  simple  and  uniserial  {exception,  the  doubtful  Stephamcrinus).  Silurian 
to  Carbon  iferous. 

The  simplest  form  of  the  Crinoidea ;  containing  only  plates  found  in  the  larval  or  very 
young  stage  of  existing  types,  without  any  supplementary  plates  whatever  except  such  as 
may  belong  to  an  arm-like  anal  tu^be.  They  are  usually  small,  one  genus,  Allagecrinus, 
alraost  microscopic.  Similar  minute  fornis  may  yet  be  found  in  the  pre-Silurian  forniations, 
from  which  their  absence  thus  far  has  been  urged  as  an  objection  to  the  validity  of  the  group, 
considered  as  a  phylogenetic  representative  of  the  larval  stage.  It  must  be  admitted  that  its 
limits  are  not  very  well  defined,  but  the  typical  form  is  Haplocrinus. 

Family  1.     Stephanocrinidae  Wachsmuth  and  Springer. 

Monocyclic.  Calyx  cup-shaped,  composed  of  three  elongate  hasals,  five  radials, 
and  five  orals,  with  ambulacra.  Radials  deeply  forked  ;  the  pi'ongs  formed  hy  the 
margins  of  two  contiguous  radials  extending  upward  between  the  arms,  in  spinelike 
processes.  First  costals  semilunate  and  resting  within  a  horseshoe-like  concavity  near 
the  outer  end  of  radial  incisions.  Tegmen  consisting  of  the  m'als,  surrounding  a 
central  space,  which  is  roofed  over  by  five  greatly  modified  ambulacrals  in  form  of 
a  flattened  pyramid  of  triangulär  plates  ;  with  anchylosed  covering  plates  extending 
outward  to  the  arm  bases.  Anal  aperture  between  posterior  mal  and  interradial 
process.  Arms  with  one  short  biserial  trunJc  to 
the  ray,  giving  off  slender  biserial,  non-pinnulate 
side  arms  from  the  outer  Shoulder  of  each  brachial. 
Ordovician  and  Silurian. 

Stephamcrinus  Conrad  {Bhombifera  Barr.) 
(Fig.  308).  This  unique  genus  is  an  inter- 
mediate  form,  variously  considered  by  different 
authors  as  a  Blastoid,  a  Cystid,  or  a  Crinoid. 
The  presence   of   branching  biserial  arms,  as  fio.  308. 

pointed    out    by    Wachsmuth    and    Springer    ^^.^^i;:;^;-^^^^^^^ 

makes    it    Unquestionably    a    CrinOld,   althOUgh    of  calyx,  natural  size ;  b,  Snmmit  aspect, 
-,    r  i  ,  •        ,  V.;^!«  ;<-    enlarsred ;    nroiecting  upper  ends  of  the 

not  normal  f or  the  present  group,  m  wtiicti  it  ^^^^^^^  ^roken  away  (after  Haii). 
is  placed  on  account  of  its  simple  and  primitive  ,  ,     . , 

type  of  calyx.  The  forked  radials,  resemblance  of  the  orals  to  the  deltoids, 
and  the  orientation  of  the  small  basal  in  the  right  anterior  position  instead 
of  the  left  anterior  as  in  other  Crinoids  with  three  basals,  are  all  characters 
which  indicate  a  close  relationship  to  the  Blastoids.  Ordovician  ;  Bohemia. 
Silurian ;  North  America. 


208 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


Family  2.     Pisocrinidae   Angelin. 

Monocydk.     Basais  three  to  five  ;  radials  five,  very  unequal,  the  riglit  posterior 
and  right  anterior  Compound,  left  posterior  and  anterior  usually 
much  the  largest.     Arms  simple,  uniserial  and  composed  of  long, 
Silurian  and  Devonian. 


Fisocrinus  de  Kon.  (Fig.  309,  A).  Calyx  small,  globose. 
B  five,  unequal,  forming  a  triangle.  Only  the  large  an- 
terior, and  the  left  posterior  radial  resting  upon  the 
basals ;  one  large  plate,  the  radianal,  serves  as  inferradial 
for  both  right  posterior  and  right  anterior  radials,  and 
also  meets  the  basals.  Anal  or  first  tube-plate  above  line 
of  radials,  foUowed  by  a  tube.  Articular  facets  of  the 
radials  impressed  between  vertical  partitions  formed  by 
the  lateral  margins  of  the  plates.  Tegmen  rarely  pre- 
served,  but  as  observed  by  Wachsmuth  and  Springer  in 
P.  pilula,  consisting  of  five  large  symmetrica!  orals,  above 
which  rises  a  narrow  anal  tube.  Arms  long,  and  com- 
posed of  extremely  elongate,  cylindrical  ossicles.  Silurian  ; 
Gotland,  Dudley,  England  and  North  America  (Niagara 
Group). 

Triacrinus  Münst.  (Fig.  309,  B).  DifFers  from  the  pre- 
ceding  in  having  but  three  B.  Wachsmuth  and  Springer 
have  shown,  however,  that  some  of  the  Eifel  specimens 
occasionally  have  five  B,  thus  leading  to  the  inference  that 
the  two  forms  are  identical.     Middle  Devonian  ;  Eifel. 

Calycanthocrinus  Follmann.  B  three.  Additional  small 
arm-bearing  plates  introduced  between  the  radials.  Lower 
Devonian ;  Germany. 

Hypsocrinus  Springer  and  Slocum.  Calyx  elongate. 
Arm  facets  wide,  shallow,  concave,  Alling  a  greater 
part  of  radial  margin. 


Fig.  309. 

A,  Pisocrinus  flagellifer 
Ang.  Silurian ;  Gotland. 
a,  Perfect  specimen,  r. 
posterior  view  ;  b,  Calyx 
Seen  from  r.  ant.  side ;  c, 
From  below.  J/x  (after 
Angelin).  B,  Triacrinus 
altus  Müll.  Devonian  ;  ß  five 
Gerolstein,  Eifel.  a 
Calyx  Seen  from  r.  post 
side ;  b,  From  below  i/i.     -r>  ,  t    i    i 

K.  ant.  radial  has  in- 
ferradial distinct  from  radianal.  Middle 
Devonian ;  North  America. 


Family  3.     Haplocrinidae  Koemer. 

MonocycUc.  Calyx  small,  pyriform  to 
Basals  five.  Three  of  the  radials 
Compound,  the  others,  left  posterior  and  an- 
terior, simple,  and  much  the  largest.  Orals 
large,  triangulär  to  pentagonal,  laterally  in 
contact.     Arms  five.     Devonian. 

Haplocrinus     Steining.    (Fig.     310). 
Arm  facets  narrow,  indented  upon  distal 
face    of    radials.      Arms   small,   simple, 
uniserial,  resting  within  deep  grooves  formed  along  the  sides  of  the  orals 
Orals  large,  pentagonal,  and   laterally  in  contact ;    the  posterior  one  inter 


H>^a 


Fig.  310. 

Haplocrirms  inesjnliformis  Goldf.  Devonian  ; 
Gerolstein,  Eifel.  a,  Calyx  seen  from  one  side ; 
fo,  öeen  from  above  ;  c,  Seen  from  below  ;  d,  Analysis 
of  calyx ;  h,  Basals ;  x,  the  three  unsymmetrical 
plates  situated  between  basals  and  radials ;  r, 
Radials ;  br,  First  arm-ossicle ;  o,  Orals  (anterior 
side  to  the  right). 


CLAS«  III  CRINOIDEA  209 

locking  with  the  others,  and  pierced  by  a  small  anal  opening.  Mouth 
subtegrainal ;  column  composed  of  thin  joints.  Not  uncommon  in  the 
Middle  Devonian  of  the  Eifel  and  Nassau ;  sparse  in  the  Upper  Devonian  of 
North  America. 

Family  4.     Allagecrinidae  Etheridge  and  Carpenter. 

Monocydic.  Galyx  very  small,  sometimes  almost  microscopic.  Basais  five,  radials 
five,  of  irregulär  form  and  size.  Some  of  the  radials  axillary  and  supporting  iwo 
arms ;  others  truncate  and  supporting  hut  one  arm ;  their  articular  facets  provided 
with  transverse  ridges  and  large  muscle  plates.     Lower  Carboniferous. 

Allagecrinus  E.  and  C.  B  completely  anchylosed  in  the  adult,  and  the 
suture  lines  between  the  orals  also  disappearing  with  age.  Stern  largest  next 
to  the  calyx,  rapidly  tapering  downward.  Carboniferous  (Kinderhook  to 
Goal  Measures) ;  Great  Britain  and  North  America. 

Family  5.     Synbathocrinidae  Wachsmuth  and  Springer. 

Monocydic.  Calyx  small,  bowl-shaped,  composed  of  three  unequal  or  of  five  equal 
basals,  and  five  nearly  equal  radials.  Tegmen  formed  by  five  small,  asymmetrical 
orals ;  between  these  and  the  posterior  radials  arises  a  long  anal  tube,  following  an 
anal,  or  first  tube-plate,  resting  on  the  Shoulders  of  the  posterior  radials.  Entire 
Upper  edges  of  the  radials  bevelled  off  so  as  to  form  straight  articular  facets,  which 
are  furnished  with  well-developed  transverse  ridges.  Arms  five,  simple ;  column 
round.     Devonian  and  Garboniferous. 

Phimocrinus  Schnitze.  The  most  primitive  form  of  the  family,  having  five 
basals,  and  traces  of  transverse  bisection  of  three  radials  as  in  Heterocrinus. 
Devonian ;  Europe. 

Synbathocrinus  Phill.  (Lageniocrinus  de  Koninck).  B  three,  unequal ;  B  five, 
quadrangular  or  pentagonal.  Anal  tube  long,  slender,  resting  partly  upon 
the  Shoulder  of  the  right  posterior  radial ;  it  is  composed  of  a  longitudinal 
series  of  strong  plates  with  a  crescentic  section  on  the  dorsal  side,  and  small 
plates  re.sembling  perisome  on  the  opposite  side.  Arms  long,  uniserial,  and 
composed  of  comparatively  thick  ossicles  with  sharp  angular  edges.  Devonian 
and  Garboniferous  ;  Great  Britain  and  North  America. 

Stylocrinus  Sandb.  Distinguished  from  Synbathocrinus  mainly  by  the 
character  of  the  radial  facets,  which  are  directed  obliquely  downward  and 
inward,  instead  of  upward  and  outward.     Devonian  ;  Europe. 

Stortingocrinus  Schnitze.     Devonian. 

Family  6.     Oupressocrinidae  d'Orbigiiy. 

Dicyclic.  Calyx  large,  basin-shaped,  composed  of  five  equal  basals  and  five  equal 
radials  ;  the  basals  enclosing  a  central  pentagonal  plate,  which  represents  five  anchylosed 
infrabasals.  Upper  faces  of  radials  broad,  truncate,  and  forming  an  even  hoitzontal 
line.  Costals  compressed,  fiange-shaped.  A  peculiar  annular  structure,  the  so-called 
'' consolidating  apparatus"  situated  onthe  upper  interior  margin  of  the  calyx  between 
the  arm-bases.  Arms  five,  simple,  uniserial  and  closely  folded  ;  they  are  composed  of 
broad,  thick  plates,  united  by  dose  sutures,  and  are  iraversed  by  a  well-developed 
VOL.  I  ^ 


210 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


dorsal  canal.     Column  pierced  hy  a  large  axial  and  three,  four  or  five  peripheral 
canals.     Devonian.     Eepresented  hy  a  single  genus,  which  probably  does  not 

belong  to  this  suborder,  but 
whose  systematic  affinities  have 
not  been  satisfactorily  deter- 
mined. 

Cupressocrinns  Goldf.  (Fig. 
311).  Tegmen  flat ;  the  greater 
part  of  it  occupied  by  the  so- 
called  consolidating  apparatus. 
This  is  composed  of  five 
petaloid,  horizontally  trun- 
cated  interradial  pieces,  which 
are  laterally  in  contact,  and 
enclose  a  large,  central  open 
Space ;  tliese  are  probably 
modified  orals,  and  served  in 
part  for  the  attachment  of 
muscles.  Five  round  aper- 
tiires,  through  which  the 
ambulacra  entered  the  calyx, 
perforate  the  divisions  between 
the  consolidating  plates ;  one 
of  the  latter  is  pierced  by  the 
anal  opening  (Fig.  311,  e). 
Arms  provided  with  a  wide 
and  deep  ventral  furrow,  lined 
on  both  sides  with  jointed, 
closely  abutting  appendages  ;  of  these  there  are  several  to  each  arm-plate, 
thus  showing  that  they  are  different  from  true  pinnules.  Middle  Devonian  ; 
Eifel,  Harz,  Nassau  and  Westphalia. 


Eifel. 


'   Fig.  311, 

Cupressocrinus  crassua  Goldf.  Devonian  ;  Gerolstein 
a,  Perfect  specimen,  natural  size  ;  b,  Cross-section  of  column  ; 
c,  Fused  infrabasals  ;  d,  Section  through  the  foldeil-up  arms, 
showing  plated  covering  of  ambulacral  furrows,  and  dorsal  canals 
perforating  the  ossicles  ;  e,  Interior  of  calyx  from  above,  showing 
the  live  consolidating  jjlates,  the  lowermost  containing  the  anal 
opening  ;  /,  Radial  pierced  by  ambulacral  opening,  but  with  wall 
covering  the  same  partly  broken  away  ;  g,  Side-view  of  radial  in 
which  the  ring-like  covering  of  the  ambulacral  opening  is  pre- 
served  intact. 


Suborder  2.     FISTULATA  Wachsmutli  and  Springer. 

Tegmen  composed  of  numerous  plates,  consisting  either  of  orals  with  supra-tegminal 
ambulacra  passing  over  their  edges,  and  interamhulacra,  or  of  more  or  less  undiffer- 
entiated  plates  without  identifiable  orals  or  amhulacrals.  Posterior  interamhulacrum 
usually  more  or  less  extended  into  a  strongly  plated  anal  tuhe  or  ventral  sac.  Arms 
jpinnulate  or  non-pinnulate,  usually  uniserial,  but  biserial  in  some  later  genera.  Base 
monocyclic  or  dicyclic.     Ordovician  to  Trias. 

The  Fistulata  are  characterised,  in  their  typical  genera,  by  a  great  develoj)ment  of  the 
posterior  interradius,  which  is  extended  upward  in  the  form  of  an  anal  tube  or  a  ventral  sac.  In 
the  forrner  case  the  anus  is  at  the  distal  end  ;  orals  are  more  or  less  represented  in  the  tegmen, 
the  posterior  one  being  often  perforated  (madreporüe).  In  the  latter  the  extension  involves 
alraost  the  entire  tegmen  ;  the  plates  of  the  sac  are  often  perforated  by  small,  round  or  slit- 
like  pores  (respiratory  pores) ;  all  traces  of  orals  are  lost ;  and  a  curious  reversal  takes  place 
in  the  position  of  the  anal  opening,  which,  instead  of  being  at  the  distal  end,  or  posterior,  is 
on  the  anterior  side  of  the  sac,  either  at  the  base,  or  part  way  up,  sometimes  through  a 
lateral  spout. 

In  some  of  the  early  families  the  radials  are  transversely  bisected  in  one,  two,  or  three 
rays,  producing  Compound  radials,  as  in  some  Larviformia.  When  three  radials  are  thus 
Compound  they  are  usually  in  the  right  posterior,  and  right  and  left  anterior  rays  ;  but  when 
there  is  only  one,  it  is  constantly  that  to  the  right  of  the  anal  area,  the  right  posterior.     The 


CLASS  III  CRINOIDEA  211 

latter  condition  is  the  longest  lived,  persisting  to  late  in  the  Carboniferous,  while  the  former 
did  not  survive  the  Devonian,  and  was  chiefly  confined  among  the  Fistulata  to  Ordovician  forms. 
The  superradial,  or  ariu-bearing  portion  of  the  plate,  is  in  sonie  earlier  forms  nmch  the 
sinallest  part,  resting  on  the  right  Shoulder  of  the  inferradial,  or  lower  portion  ;  in  others  it 
is  nearer  equal  to,  and  directly  in  line  with  the  inferradial ;  in  later  forms  it  is  pushed  to  the 
right  by  the  gradual  increase  in  width  of  the  posterior  interradius  or  ventral  sac. 

The  inferradial,  because  of  its  supporting  the  sac,  as  is  usually  the  case  among  the  later 
forms,  has  received  the  name  of  radianal.  Primitively,  however,  as  was  shown  first  by 
Wachsmuth  and  Springer,  and  subsequently  by  Carpenter  and  Bather,  the  radianal  represents 
the  lower  portion  of  the  right  posterior  radial ;  and  it  has,  therefore,  nothing  in  common 
with  the  anal  plate,  which  is  a  specialised  interradial.  The  phases  exhibited  by  the  radianal 
in  its  progressive  structural  development  furnish  excellent  differential  characters.  From  its 
])riniitive  radial  position  directly  und  er  the  right  posterior  ray,  it  shifts  upward  to  a  left 
oblique  position,  and  is  then  eliminated  in  the  later  Carboniferous,  substantially  parallel  to  its 
course  in  the  Flexibilia. 

Under  the  Fistulata  are  included  the  foUowing  families  ;  Hyhocrinidac,  Meter ocrinidae, 
A7iomaloerinidae,  Calceocrinidae,  Catillocrinidae,  Belemnocrinidae,  comprising  the  monocyclic 
forms  ;  and  Dendrocrinidae,  Crotalocrinidae,  Cyathocrinidae,  with  subfamilies  Carahocrininae, 
Gaster ocominae  and  Gyathocrininae  ;  Botry ocrinidae ;  Poieriocrinidae,  with  subfamilies 
Poteriocrininae,  Graphiocrininae  and  Encrininae,  comprising  the  dicyclic  forms. 

Family  1.     Hybocrinidae  Zittel. 

Monocyclic  ;  basals  five.  Eadials  large  ;  the  right  posterior  radial  Compound  ; 
the  inferradial  almost  as  large  as  the  other  radials,  supporting  on  its  right  Shoulder 
the  superradial,  and  on  its  left  the  first  plate  of  the  tube,  or  anal  plate,  which  does  not 
enter  the  dorsal  cup.  Ventral  tube  or  sac  in  its  most-  primitive  form,  extending  hut 
little  above  the  rest  of  the  tegmen ;  superradial  very  small,  sometimes  undeveloped. 
Arm  facet  small,  round,  less  than  width  of  radial;  arms  simple,  uniserial,  mm- 
pinnulate.  Orals  large,  with  ambulacra  resting  on  their  adjacent  edges ;  posterior 
one  pierced  by  hydropore.     Lower  Ordovician. 

Hybocystis  Wetherby.  Three  of  the  rays  bearing  primitive  arms  composed 
of  but  few  joints,  with  ambulacral  furrows  passing  from  the  ventral  to  the  dorsal 
side  of  the  arms,  and  continued  upon  the  surface  of  the  R.  The  two  other 
rays  are  without  arms,  and  the  ambulacra  follow  the  surface  of  the  calyx,  and 
may  pass  down  so  far  as  to  enter  the  basals.  Anus  through  a 
valvulär  pyramid  surrounded  by  integument  of  small  plates 
between  posterior  oral  and  distal  edge  of  the  anal  plate.  Stem 
round.     Ordovician  (Trenton) ;  Kentucky  and  Canada. 

Hybocrinus  Billings.  Similar  to  Hybocystis,  but  with  five 
regulär  arms,  and  no  recurrent  ambulacra.  Anus  either 
through  a  valvulär  pyramid  or  simple  opening.  Ordovician 
(Trenton) ;  Canada  and  Kentucky.  ^^°'  ^^^' 

Hoplocrinus  Grewingk  (Fig.  312).  Like  the  preceding,  ^Z'^^G^ZinÜ: 
but  with  the  inferradial  sloping  only  to  the  right,  and  sup-  ordo^^ijian^^  ^^st. 
porting  a  small,  trigonal  superradial.  On  the  left  it  supports  seen  irrom  the  anai 
small  plates  of  the  ventral  sac,  without  the  Intervention  of  a  ^if^k).^*^^'  °'" 
larger  plate.     Ordovician  ;  St.  Petersburg. 

Baerocrinus  Volborth.  Like  Hoplocrinus,  but  the  right  posterior  and  the 
anterior  ray  without  arms;  apparently  inferradials  only  are  developed. 
Ordovician ;  St.  Petersburg. 

Family  2.     Heterocrinidae  Zittel. 

Monocyclic ;  basals  five.  Galyx  usually  elongate  conical.  One  or  mwe  of  the 
radials  Compound.      The  superradial  of  the  right  posterior  ray  supporting  to  the 


212  ECHINODERMATA— PELMATOZOA  phylum  iv 

rigU  the  primary  brachials,  and  to  the  left  an  anal  tube  or  sac ;  the  first  plate  of 
this,  corresponding  to  the  anal  x,  may  he  entirely  above  the  level  of  the  radials,  or,  as 
usually,  may  slightly  indent  their  upper  corners  at  the  posterior  interradial  suture ; 
but  never  fully  enters  the  dorsal  cup.  Arms  non-pinnulafe,  uniserial,  dichotomous  or 
heterotomous.  Eadiäl  facets  usually  wide  and  straight.  Tegmen  not  well  known. 
Ordovician  and  Silurian. 

Heterocrinus  Hall  (Stenocrinus  W.  and  Sp.).  Crown  subcylindrical,  calyx 
small.  Three  radials  transversely,  more  or  less  equally  bisected,  or  Com- 
pound ;  these  being,  in  addition  to  the  right  posterior,  the  right  and  left 
anterior,  or  sometimes  the  anterior  in  place  of  the  latter.  Anal  tube  delicate 
and  straight;  first  tube-plate  resting  on  the  Shoulders  of  both  posterior 
radials,  but  not  further  entering  the  cup.  Arms  irregularly  dichotomous, 
somewhat  divergent.  Stern  pentagonal,  quinquepartite,  with  interradial 
sutures.     Ordovician ;  North  America. 

Ohiocrinus  W.  and  Sp.  Calyx  and  stem  as  in  Heterocrinus.  Arms  hetero- 
tomous, having  ten  main  branches  not  in  close  contact,  and  somewhat  sinuous, 
with  ramules  which  usually  brauch  again.  Ventral  sac  large,  and  usually 
convoluted.     Ordovician  ;  North  America. 

Eäenocrinus  S.  A.  Miller  {Heterocrinus  W.  and  Sp.,  non  Hall).  Calyx  about 
as  in  the  preceding.  Arms  heterotomous,  with  ten  main  branches,  straight, 
rather  closely  abutting,  composed  of  a  continuous  series  of  syzygies  of  two 
plates  each,  the  epizygals  giving  off  ramules.  Stem  round,  tripartite. 
Ordovician ;  North  America. 

locrinus  Hall.  Only  one  radial  Compound,  the  right  posterior,  the  lower 
part  of  which  is  of  about  the  same  size  as  the  other  radials,  which  are  all  large. 
The  superradial  is  short,  resembling  an  axillary  brachial,  supporting  on  its 
right  Shoulder  an  arm  and  on  the  left  a  series  of  plates  f orming  the  arm-like 
dorsal  ridge  of  a  strong  anal  tube  or  sac,  of  complicated  structure ;  first  tube 
plate  entirely  above  the  level  of  radials,  and  not  entering  the  dorsal  cup  at  all. 
Arms  dichotomous,  branching  frequently.  Stem  pentagonal,  quinquepartite, 
with  interradial  sutures,  the  pentameres  radially  disposed.  Ordovician ; 
North  America. 

Herpetocrinus  Salter  (Ophiocrinus  Charlesw.;  Myelodactylus  and  (?)  Brachio- 
crinus  Hall).  A  specialised  form  with  crown  of  the  locrinoid  type,  habitually 
enclosed  by  the  coiled  stem,  whose  structure  is  modified  accordingly.  The 
crown  is  rarely  seen,  being  beut  backward,  and  usually  closely  enveloped  by 
the  stem,  which  is  then  coiled  around  it  in  the  opposite  direction.  One  ray  is 
dwarfed,  either  not  branching  or  entirely  aborted.  The  right  posterior  radial 
alone  is  Compound,  the  superradial  supporting  the  series  of  tube-plates  entirely 
above  the  level  of  the  radials,  as  in  locrinus.  Anal  tube  long  and  narrow, 
composed  of  a  series  of  heavy  plates  resembling  brachials  dorsally,  with 
perisome  on  the  other  side.  Arms  more  or  less  irregularly  dichotomous.  The 
stem  could  be  tightly  coiled,  or  uncoiled  exposing  the  crown ;  but  the  latter 
condition  is  rarely  found  in  the  fossils.  Resulting  from  this  the  stem  has  lost 
its  cylindrical  form,  being  more  or  less  concave  at  one  side,  with  its  columnals 
crescentric  in  section,  and  bearing  on  the  horns  of  the  crescents  two  longitudinal 
rows  of  strong  cirri.  The  remarkable  resemblance  of  the  coiled  cirriferous 
stem  to  a  pinnulate  arm  has  misled  many  students,  for  the  crown  is  usually 
concealed.     Silurian  ;  North  America  and  Europe. 


CLASS  III  CRINOIDEA  213 

Family  3.  Anomalocrinidae  Wachsmuth  and  Springer. 
Monocyclic  ;  basalsfive.  Calyx  hroadly  rotund  in  form.  Tegmen  strong,  composed 
chieflg  of  large  modified  amhulacrals  and  interamMacrals,  extending  posteriorly  into 
a  large  expanding  anal  tube  or  sac.  Radiais  very  large,  two  of  them—the  right 
posterior  and  left  antero-lateral— Compound,  all  of  them  laterally  in  contad  ;  inf  erradial 
rarely  larger  tlian  the  superradial;  the  lower  tuhe-plate,  or  anal  x,  resting  in  the 
angle  formed  hy  the  superradial  to  the  right,  and  the  upper  end  of  the  simple  radial 
to  the  left,  hut  not  entering  the  cup.  Radial  facets  circular  and  very  small.  Arms 
relatively  slender,  uniserial,  and  bifurcating  several  times  at  somewhat  irregulär 
intervals.  Small  armlets  given  off  from  each  arm-joint  on  one  side  only,  alter nately 
in  the  successive  dichotoms.  Column  strong,  round,  attached  by  an  encrusting  root. 
Ordovician. 

Anomalocrinus  M.  and  W.  (Ataxocrinus  Lyon).  The  only  genus  of  the 
family.  The  Statements  heretofore  current  that  one  radial  is  often  longi- 
tudinally  bisected,  and  that  the.re  is  a  small  supplementary  piece  within 
the  basal  ring,  are  based  on  abnormal  specimens  only.  Ordovician ;  North 
America. 

Family  4.     Cremacrinidae  Ulrich  (Galceocrinidae  M.  and  W.). 

Monocyclic  Inadunata,  in  which  a  bilateral  symmetry  along  the  left  anterior 
radius  and  right  posterior  interradius  has  been  superinduced  in  conjunction  with 
bending  of  the  crown  on  the  stem  in  such  a  way  that  the  right  posterior  interray  lies 
along  the  stem  ;  with  the  left  anterior,  right  posterior  and  right  anterior  radials  Com- 
pound ;  with  anal  x  (IRA)  shifted  over  the  right  posterior  radius,  usually  into  the 
right  posterior  interradius,  and  supporting  a  massive  tube ;  with  three,  rarely  four, 
arms,  of  which  two  are  as  a  rule  peculiarly  modified  and  bear  armlets  or  pinnules. 
(From  Bather,  "  The  Crinoidea  of  Gotland.")  Ordovician  to  Lower  Carbon- 
iferous. 

Cremacrinus  Ulr.  (Castocrinus  Ringueb.).  B  distinct,  all  entering  into  the 
articular  surface  of  the  stem.  The  right  posterior,  and  right  anterior  super- 
radials  joined  by  ill-defined  close  suture,  each  abutting  with  one  side  on  the 
adjacent  large  simple  R.  The  lower  plate  of  the  tube  supported  by  the 
right  posterior  superradial  only,  while  the  right  anterior  superradial  supports 
the  first  brachial  of  the  right  anterior  arm.  The  right  posterior  and  right 
anterior  superradials  separated  from  one  another,  and  also  from  the  ventral 
tube,  by  the  right  posterior  and  right  anterior  R.  Arms  four.  Ordovician  ; 
North  America.     Type,  C.  punctatus  Ulr. 

Euchirocrinus  Meek  and  Worthen  (Cheirocrinus  Hall,  wow  Eichwald ;  Pro- 
clivocrinus  Ringueb.).  B  unfused,  or  perhaps  sometimes  the  left  posterior  fused 
with  the  left  anterior  one.  The  right  posterior  and  right  anterior  super- 
radials fused  in  a  T-shaped  piece,  which  abuts  with  either  wing  on  the 
Corners  of  the  large  simple  R.  The  right  posterior  and  right  anterior 
inferradials  separated  from  one  another  and  from  the  tube  by  the  T-piece ; 
tube  supported  by  the  whole  Upper  margin  of  the  latter.  Arms  three. 
Silurian  ;  North  America.     Type,  E.  chrysalis  (Hall). 

Deltacrinus  Ulrich  {Cheirocrinus  Salter,  nom.  nudum ;  Calceocrinus  Hall  em. 
Ringueberg).      Left  posterior  basal  fused  with  the  left  anterior  one ;    the 


214  ECHINODEEMATA— PELMATOZOA  phylum  iv 

fused  plates  very  rarely  entering  the  stem  articulation.  The  posterior  and 
right  anterior  basals  bounded  for  some  distance  by  the  large  R.  T-plate 
separated  from  the  large  simple  R  by  the  right  posterior  and  right  anterior 
radials  ;  it  is  low,  wide,  and  occasionally  very  small.  Tube  supported  by 
the  T-piece  and  the  two  inferradials  to  the  right,  but  not  touching  the  two 
large  simple  radials.  Arms  three.  Silurian  and  Devonian ;  Europe  and 
America.     Type,  D.  clarus  (Hall). 

Halysiocrinus  Ulrich  em.  Bather.  B  as  in  the  preceding,  but  the  fused 
posterior  and  right  anterior  ones  never  entering  into  the  stem  articulation. 
T-piece  either  obsolete  or  concealed  between  the  right  posterior  and  right 
anterior  inferradials,  and  the  two  large  radials  in  the  stem  articulation. 
Tube  supported  by  the  inferradials  to  the  right,  which  are  in  contact,  and 
abutting  by  its  lower  corners  on  the  two  large  simple  R.  Arms  three.  Bur- 
lington and  Keokuk  Groups ;  Mississippi  Valley.     Type,  H.  dadylus  (Hall). 

Family  5.     Oatillocrinidae  Wachsmuth  and  Springer. 

Base  monocyclic ;  dorsal  cup  low  and  broad ;  general  symmetry  of  the  calyx 
greatly  disturbed.  Basals  more  or  less  fused,  their  number  doubtful ;  radials  still 
more  irregulär  bofh  in  form  and  in  size.  Most  of  the  arms  given  off  from  two  of 
the  radials,  which  are  sometimes  five  or  six  times  larger  than  the  other  three  ;  they 
are  simple,  qnadrangular,  non-pinnulate,  and  rest  within  small  sockets  directly  upon 
the  radials.  Anal  plates  wanting.  Anal  tube  heavy,  composed  of  very  long, 
longitudinally  arranged  crescent-shaped  pieces,  and  supported  directly  by  the  radials  ; 
it  exhibits  a  wide  open  groove  along  the  anterior  side,  which  probably  was  covered  by 
small  delicate  plates.     Devonian  and  Lower  Carboniferous. 

Mycocrinus  Schultze.  Dorsal  cup  mushroom-shaped.  Plates  massive, 
irregulär,  and  without  ornamentation.  B  two  (according  to  Schultze),  one  of 
them  twice  as  large  as  the  other,  and  the  two  forming  a  knob-like  body.  R 
five,  their  inner  edges  resting  upon  the  angular  margin  of  the  basal  disk ;  they 
spread  broadly  outward  from  the  B,  extending  far  beyond  them.  The  two 
larger  R  separated  at  the  posterior  side  by  two  equal  smaller  plates ;  and  at 
the  anterior  side  by  a  single  plate  having  a  quite  narrow  upper  face.  M. 
boletus  Schultze  has  apparently  fif teen  arms,  their  structure  unknown.  Middle 
Devonian ;  Eifel.  , 

Catillocrinus  Shumard  ex  Troost  (Nematocrinus  M.  and  W.).  Crown,  when 
the  arms  are  closed,  elongate,  cylindrical.  Dorsal  cup  basin-shaped,  concave  at 
the  base,  truncate  at  its  upper  margin.  Basal  disk  small.  R  five;  those 
of  the  two  antero-lateral  rays  fully  six  times  as  wide  as  the  others,  and 
expanding  upwards,  so  as  to  encroach  upon  the  smaller  ones.  The  larger  R 
Support  each  twelve  to  sixteen  arms ;  the  smaller  ones  rarely  more  than  one 
each.     Lower  Carboniferous  ;  North  America. 

Family  6.     Belemnocrinidae  Wachsmuth  and  Springer. 

Base  monocyclic ;  cylindrical  to  ovoid.  B  is  composed  of  five  large,  elongate, 
irregulär  pieces,  and  is  pierced  by  a  small  canal  which  widens  slightly  at  the  upper 
end.  Radials  five,  quadrangidar,  and  separated  posteriorly  by  a  narrow  anal. 
Ventral  sac  large,  composed  of  hexagonal  plates,  the  angles  of  which  are  perforated. 


CLASS  III  CRINOIDEA  215 

Arms  long,  giving  off  armlets  alternately  at  intervals.  Column  round  or  pentaganal ; 
in  the  latter  case  having  its  angles  radially  directed,  and  cirri  which  are  interradial. 
Lower  Carboniferous. 

Belemnocrinus  White  {Missouricrinus  S.  A.  Miller).  The  only  genus,  very 
rare.     Burlington   Group  ;  Mississippian  area,  North  America. 

Family  7.     Dendrocrinidae  Bather. 

Dicydic.  Strudure  of  tegmen  not  well  kiiown,  prohahly  composed  chiefly  of 
undifferentiated  plates,  more  or  less  extended  into  a  tube  or  sac,  sometimes  resemhling 
an  arm  proximally,  and  usually  with  anal  opening  at  the  distal  end.  Arms  uniserial^ 
either  dichotomous  and  stridly  non-pinnulate,  or  heteroiomous  with  main  rami  hearing 
lateral  ramules  tending  to  incipient  pinnulation.  Loose,  irregulär  interhrachials 
occasionally  present  in  lower  pari  of  interradius  in  some  genera.  Radianal  in 
primitive  position  in  form  of  radial  under  the  right  posterior  ray.  Radial  facets 
Wide  or  narrow ;  mode  of  union  with  proximal  bradiials  not  well  knovm,  hui 
prohahly  Inj  modified  or  imperfed  muscidar  articulation.  Infrahasals  five.  Stem 
usually  round,  sometimes  pentagonal  and  quinquepartite.     Ordovician  and  Silurian. 

This  assemblage  of  early  genera  raay  be  considered  as  a  sort  of  composite  family,  in  which 
are  embraced  a  nimiber  of  characters  which  later  became  fixed  as  valid  family  criteria.  They 
are  all  primitive  in  the  position  of  the  radianal,  and  therein  differ  from  all  later  Fistulata. 
The  presence  of  interhrachials  irregularly  in  some  genera,  e.g.  Cupulocrinus  and  Oitawacrinus, 
which  are  foreign  to  the  Inadunata,  indicates  a  close  relation  to  the  Flexibilia  ;  and  as 
Springer  has  shown,  there  are  good  reasons  for  considering  the  first  of  these  genera  as  very 
close  to  the  ancestral  type  of  the  two  orders. 

Merocrinus  Walcott.  Arms  dichotomous,  branching.  Radial  facets  wide, 
shallow,  nearly  straight.  No  anal  plate  in  line  with  radials.  Anal  tube  at 
the  base  resembling  an  arm  branching  from  the  left  side  of  the  axillary  right 
posterior  superradial.  The  genus  might  be  considered  as  a  dicyclic  locrinus. 
Ordovician  ;  North  America  and  England. 

Cupulocrinus  d'Orb.  (Scyphocrinus  Hall,  non  Zenker).  Arms  and  radial 
facets  about  as  in  the  preceding.  Large  anal  x  in  line  with  radials,  truncate 
above,  supporting  a  large  tapering  anal  tube,  with  a  median  row  of  large 
plates  dorsally,  bordered  by  perisome,  rising  only  about  half  the  height  of 
the  arms.  Small  irregulär  interhrachials  often  present  in  primary  axils. 
Ordovician  ;  Canada  and  Kentucky. 

Thenarocrinus  Bather.  Dorsal  cup  similar  to  the  preceding,  but  radianal 
slightly  to  left  and  touching  infrabasals.  Anal  tube  large  and  long,  composed 
of  transversely  folded  plates,  without  median  ridge  or  perisome.  Silurian ; 
England. 

Dendrocrinus  Hall.  Radial  facets  narrow  and  semicircular.  Arms  dicho- 
tomous, branching  many  times,  and  very  slender.  Anal  x  in  line  with  radials, 
angular  above.  Anal  tube  wide,  long,  composed  of  hexagonal  plates  in 
vertical  parallel  columns.      Ordovician  and  Silurian ;  North  America. 

Ottawacrinus  W.  R.  Billings.  Arms  heterotomous,  with  ten  main  branches, 
bearing  lateral  ramules,  which  may  subdivide,  or  may  approach  the  pinnulate 
stage.  Anal  x  in  line  with  radials ;  tube  wide,  rising  the  füll  height  of  the 
arms.     Radial  facets  wide  and  nearly  straight.     Ordovician  ;  Canada. 

Gothocrinus  Bather.  Similar  to  preceding,  but  with  radial  facets  narrow 
and  curved,  and  shorter  ramules.     Silurian ;  Gotland. 


216 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


Family  8,     Crotalocrinidae  Angelin  (emend.  Wachsm.  and  Springer), 

Dicydic.  Infrahasals  five.  Calyx  resembling  that  of  Cyathocrinus,  hut  with 
lower  brachials  more  or  less  rigidly  incorporated  into  dorsal  cup  by  lateral  contact 
among  themselves,  with  the  radials,  and  with  tegmen  plates.  Tegmen  composed  of 
numerous  rigid  plates,  chiefly  modified  ambulacrals  and  interambulacrals,  with  orals 
more  or  less  exposed,  and  alternating  covering  plates  often  very  definitely  arranged. 
No  interradials  except  at  anal  side.  No  radianal ;  anal  x  in  line  with  radials  ; 
anus  directly  through  the  tegmen  or  at  the  end  of  a  short  protuberance.  Arms  non- 
uniserial.     Axial  canal  in  arms  distind.     Stem  large,  round.     Silurian. 


The  systematic  position  of  this  family  is  uncertain.  The  usual  rigid  incorporation  of  the 
lower  brachials  in  the  dorsal  cup  by  inclusion  within  the  radial  facet,  and  by  eonnection 
with  solid  tegmen,  analogous  to  what  is  seen  in  camerate  genora  like  Marsipocrinus  and 
Pterotocrinus,  points  to  a  eonnection  with  the  Camerata,  as  claimed  by  Wachsmuth  and 
Springer.  This  feature  is  subject  to  considerable  Variation,  being  usually  not  so  pronounced 
in  young  specimens,  in  which  the  brachials  are  more  nearly  isolated.  On  the  other  band  the 
resemblance  in  habitus  of  calyx  to  the  Inadunata,  as  Bather  has  suggested,  is  equally 
striking  ;  while  the  absence  of  pinnules  in  the  arms  seems  to  this  reviser  a  strong  reason 
in  favour  of  Inadunate  affinities,  The  structure  of  the  tegmen  would  place  it  close  to  the 
Cyathocrinidae. 

Enallocrinus    d'Orb.       Infrabasals    five.       Anal    plate    one,    not    always 
truncating   the    posterior    basal.     Radial  facets   wide    and   shallow,   bearing 


Fig.  313. 
A,  Crotalocrlnv.ii  pulcTier  Hising.  {Anfhocrinus  loveni  Müller).  Silurian  ;  Gotland.  Crown  with  folded  arms. 
7>,  Portion" of  stem.  C,  Cross-section  of  four  contiguous  arm-ossicles  of  the  network.  D,  Dorsal  aspect  of 
arm-plates,  showing  their  intimate  union ;  those  above  the  two  rows  ttgured  have  been  broken  away  so  as  to 
expose  the  side-pieces  and  covering  plates  of  the  ambnlacral  furrows.  E,  Tegmen  of  C.  rugosus  Miller  (after 
Angelin). 


directly  on  their  distal  edge  a  triangulär  primibrach  and  one  to  three  further 
Orders  of  brachials  at  each  side.  Arms  long,  frequently  dichotomising,  and 
becoming  free  above  the  first  few  brachials.     Silurian ;  Gotland,  England. 

Crotalocrinus  Austin  (Anthocrinus  Müller)  (Fig.  313).     Similar  to  Enallo- 
crinus,   but    arm-branches    united    by   lateral   processes   from   each   brachial. 


CLASS  III  CRINOIDEA  217 

forming  a  flexible  network,  which  may  be  continuous  all  arouiul  the  crown 
or  be  divided  into  five  broad,  reticulate,  fan-like  fronds.  In  the  calyx  of 
some  young  specimens  the  radial  facet  is  narrow,  semicircular,  evidently 
beariiig  the  brachials  in  the  usual  succession.  Axial  canal  distinct  in  arms 
but  not  perforating  radials,  which  are  thin.  Stern  terminating  in  a  thick, 
branching  root.     Silurian  ;  Gotland,  England  and  North  America. 

Petalocrinus  Weller,  from  the  Silurian  of  North  America  and  Gotland, 
with  its  arms  united  by  lateral  fusion  into  five  ponderous  fans,  has  some 
resemblance  to  Crotalocrinus,  but  seems  to  have  no  anal  plate.  It  may  be 
nearer  to  the  Gasterocrinidae. 

Family  9.     Cyathocrinidae  Roemer  (emend.  Wachsm.  and  Springer).^ 

DkycUc.  Tegmen  strong,  composed  of  rather  large  orals  more  or  less  exposed^ 
surrounding  but  not  covering  the  peristome ;  rigid  amhulacrals  supported  on  their 
adjacent  edges,  meeting  dbove  the  oral  centre  and  often  greatly  modified ;  and  inter- 
amhulacrals,  which  often  encroach  upon  and  ohscure  the  other  plates.  Posterior  oral 
frequently  a  madreporite.  Anus  located  either  in  the  posterior  interamhidacrum 
directly  through  the  tegmen,  or  at  the  distal  end  of  a  plated  anal  tuhe,  or  dorsally 
through  the  side  of  the  cup.  Arms  non-pinnulate.  Radial  facet s  usually  semi- 
circular, less  than  the  width  of  the  radial.  Union  of  radials  with  proximal  brachials 
usually  by  incomplete  articulation  upon  undifferentiated  Joint  faces,  with  concavo- 
convex  surfaces,  without  true  transverse  ridge,  though  with  occasional  traces  of  it. 
Infrabasals  usually  five.     Stem  usually  round. 

Subfamily  A.     Carabocrininae. 

Arms  usually  dichotomous  ;  heterotomous  in  some  of  the  later  genera.  Radianal 
obliquely  to  left  of  right  posterior  radial.  Anal  x  present.  Posterior  oral  usually 
a  madreporite.  Infrabasals  five.  Stem  usually  round.  Ordovician  to  Lower 
Carboniferous. 

Carabocrinus  Billings.  RA  completely  separating  BB,  and  having  a 
supplemental  plate  intercalated  below  it,  touching  IBB.  Anal  x  large,  in 
line  with  radials.  Anus  directly  through  the  teg- 
men. Arms  branching.  Posterior  oral  pierced  by 
hydropore.  Ordovician  (Trenton)  ;  Canada  and 
Kentucky. 

Strophocrinus  Sardeson.      Ordovician  ;  Minnesota. 

Porocrinus  Billings  (Fig.  314).  RA  smaller,  rhom- 
boidal, not  separating  BB.  Arms  ten,  unbranched. 
Calyx  plates  deeply  folded  at  the  angles,  but  folds 
do  not  cross  the  sutures  or  form  true  pore-rhombs.  Fi«.  3i4. 

Anus  in  a  slight  protuberance.     Referred  by  some  ord^^r;"  mTa^t"  cÄ 
authors  to  the  Cystids.     Ordovician:  Canada,  Ken-  Nat.  size  (aoer  Biiiings) ;  h,p. 

,  .  T--         .   "^  '  radiatus  Beyr,     Ordovician ;  8t. 

tUCky  and  KuSSia.  Petersburg.     Calyx  plates  show- 

Palaeocrinus  Billings.     RA  as  in  preceding  genus.  i^;,*!/^^;!;  ilVS'ßeyrSr 
Arms  branching  several  times ;  slender,  rising  from 
a  small  curved  facet.     Anal  tube  small.     Ordovician ;  Canada  and  Kentucky. 

Homocrinus  Hall.  RA  as  in  preceding.  Arms  branching,  strong  ;  radial 
facets  wider  than  usual   in   the  family,  nearly  straight.      Anal  tube  large, 


218 


ECHINODERMATA— PELMATOZOA 


THYLUM  IV 


Silurian  and  Devonian  ;  North  America 
Similar   to    Homocrinus,    but    with 


composed  of  numerous  small  plates. 

and  Europe. 

Bactrocrinus   Schnur,  in   Steininger. 

narrower  facets.     Devonian  ;  Germany. 

Euspirocrinus  Angelin  (Fig.  267).     Dorsal  cup  conical.     EA  small,  pent- 

agonal.      Anal  x  rising  above   level   of  BB,  with  a  plate  of  the  anal  tube 

partly   in    the  cup  beside   it.      Anus  at  the  end  of  a  strong  tube.     Arms 

dichotomous,  branching.     Ordovician  ;  Canada.     Silurian  ;  Gotland. 

Closterocrinus  and  Ampheristocrinus  Hall.     Imperfectly  known.     Silurian  ; 

North  America. 

Sphaerocrinus  Roemer.      Dorsal  cup  globose.      BA  larger ;   x  not  rising 

above  BB.     Anus  directly  through  the  tegmen.     Axial  canal  separate  from 

ventral    groove    in    radials    and    brachials.     Arms 
unknown.     Devonian ;  Germany  and  England. 

Parisocrinus  W.  and  Sp.  (Fig.  315,  which  is 
reversed).  Dorsal  cup  elongate.  BA  large  ;  x  not 
rising  above  level  of  BB.  Anal  tube  very  broad 
and  long,  rising  to  height  of  the  arms,  composed 
of  hexagonal  plates  and  profusely  perforated  with 
pores  at  the  sides  of  the  plates ;  anus  at  the  distal 
end,  surrounded  by  a  circlet  of  strong  plates. 
Arms  dichotomous,  branching  frequently.  Devon- 
ian to  Lower  Carboniferous  (Keokuk) ;  Germany, 
England  and  North  America. 

from  the  anal  side,  showing  ventral        Vasocfinus  Lyou.     Calyx   broad,  hemispherical. 

sac  and  one  arm  which  is  recuper-      .  t_    -         ^  -j.!.     x  •  •    r,         • 

ated  and  abnormaiiy  small  (right  Arms  heterotomous,  With  teu  mam  rami  bearmg 
'^.^^^:^S^tS^^i^^.   strong  ramules  which  may  brauch  again  ;  therami 

divergent,  and  not  in  contact  above  the  axillary 
Anal  tube  broad  below,  rather  short  and  tapering. 
not  divided,  and  with  very  small  axial  canal. 
Devonian  to  Lower  Carboniferous  (Keokuk) ;  North  America. 

Barycrinus  Wachsmuth.  Calyx  and  arms  as  in  Vasocrinus,  but  rami  and 
ramules  usually  heavier.  Rami  in  contact  by  one  or  two  brachials  above  the 
axillary.  BA  small,  quadrangular,  frequently  entirely  wanting,  in  which 
case  a  small  specimen  cannot  certainly  be  distinguished  from  Cyathocrinus  by 
the  calyx  alone,  although  in  general  the  arm  facets  are  larger,  and  directed 
upward  more  than  in  that  genus.  Anal  tube  broad  and  short.  Stem  un- 
usually  large,  quinquepartite,  with  a  very  wide  axial  canal.  Specimens 
attaining  a  large  size.  Lower  Carboniferous  (Lower  Burlington  to  Warsaw) ; 
Mississippian  area.  North  America. 

Goniacrinus  Miller  and  Gurley.  Calyx  small,  elongate.  Arms  hetero- 
tomous, with  small  ramules  borne  on  ten  main  branches ;  facets  directed 
upward.  BA  small.  Anal  x  in  line  with  radials,  followed  by  others  in  a 
prominent  series  between  the  posterior  rays,  passing  into  a  tube.  Lower 
Carboniferous ;  North  America. 

Atelestocrinus  W.  and  Sp.  Calyx  elongate.  Arms  heterotomous,  with 
delicate  ramules.  BA  of  good  size.  Anterior  ray  is  not  arm-bearing. 
Lower  Carboniferous  (Burlington) ;  Mississippian  area.  North  America. 


Fig.  315. 

Parisocrinus  eurtus  Müll 
ian ;    Schönecken,  Eifel. 


Devon - 
a,  Calyx 


primibrach.     BA  small. 
Stem    of    moderate    size, 


CLASs  III  CRINOIDEA  219 

Subfamily  B.     Gasterocominae. 

Cyathocrinidae  with  no  radianal.  Anus  through  the  dorsal  cup,  below  level  of 
rm  hases.  Arms  strong,  round;  facet  horse-shoe  shaped,  direded  outward,  arid 
ierced  hy  a  distinct  axial  canal.     Infrabasals  usually  undivided,  exceptionally  three 

or  five.     Orals  largely  covered  hy  modified  ambulacrals  ;  posterior  one  a  madreporite. 

Stern  round,  with  central  axial  canal  surrounded  hy  three  or  more  peripheral  canals. 

A  strongly  specialised  subfamily  of  short  life,  being  limited,  except  for 
Hypocrinus,  to  the  Middle  Devonian. 

Gasterocoma  Goldfuss  {Epactocrinus  and  Ceramocrinus  Job.  Müller)  (Fig. 
316).  Infrabasal  disk  sraal],  undivided.  Anal  opening  lateral  through  the 
dorsal  cup,  just  above  the  posterior 
basal,  at  the  angle  formed  by  that 
plate  and  the  two  posterior  radials, 
usually  fringed  with  a  ring  of  small 
plates ;  one  or  more  plates  may  lie 
above  it,  connecting  with  the  tegmen, 
or  these  may  be  absent,  leaving  the 
radials  closely  abutting.     Axial  open-  fio.  sie. 

ing  in  infrabasal  disk  COmpleX,  COnsist-         Gasterocoma    antlqua    Goldf.    Devonian  ;     Prüm, 
r  j.      1         j   ii.  r  n  Bifel.     a,  Calyx  seen  from  one  side ;  h,  Anal  aspect ; 

ing  ot  a  central  and  three,  f our  or  üve  c,  Tegmen.   2/j  (after  l.  scimitze). 
peripheral  canals,  continued  down  into 

the  column.  Stem  round,  with  strongly  alternating  joints,  the  thin  proximal 
columnal  more  or  less  quadrangular.  Arms  not  certainly  known,  but 
divergent,  directed  outward,  probably  round  and  simple,  with  short  brachials. 
Middle  Devonian ;  Eifel.  The  remaining  genera  mostly  agree  with  this  in 
the  essential  structures  of  the  calyx. 

Schultzicrinus  Springer.  Arms  directed  upward,  simple,  broad,  abutting, 
with  long  brachials  following  one  very  short  primibrach.  Devonian 
(Onondaga) ;  New  York. 

Arachnocrinus  Meek  and  Worthen.  Arms  branching"  more  than  once. 
Devonian  (Onondaga) ;  New  York  and  Kentucky. 

Nanocrinus  Joh.  Müller.  Only  four  arm-bearing  radials.  Arms  unknown. 
Scoliocrinus  Jaekel.     Three  arm-bearing  radials.     Middle  Devonian  ;  Eifel. 

Achradocrinus  Schnitze.  Infrabasals  five,  not  fused.  Axial  canal  simple, 
without  peripherals.     Middle  Devonian ;  Eifel. 

Hypocrinus  Beyrich  may  belong  here.  Resembling  Achradocrinus,  but 
with  three  infrabasals.     Ciassed  by  authors  as  a  Cystid.     Permian ;  Timor. 

Myrtillocrinus  Sandb.  Has  the  general  facies  of  this  family  ;  undivided 
infrabasal  disk,  a  central  axial  with  three  or  four  peripheral  canals ;  round, 
simple  arms.  But  there  are  five  large  symmetrical  orals  in  a  pyramid  con- 
stituting  almost  the  entire  tegmen,  leaving  only  small  interoral  grooves  for 
the  ambulacra, — not  preserved  in  any  specimens.  Anal  opening  not  known, 
probably  minute,  and  obliterated  by  Infiltration  of  calcareous  matter  in 
fossilising.     Middle  Devonian  ;  Eifel  and  New  York. 

Subfamily  C.     Cyathocrininae. 

Cyathocrinidae  with  no  radianal.  Anus  at  the  ventral  side,  usually  at  the  end 
of  a  strong  tuhe.      Anal  x,  when  pi-esent,  in  line  with  radials.      Arms  usually 


220 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


dichotomous,  and  freely  branching.  Posterior  oral  usually  a  madreporite ;  other 
orals  often  largely  hidden  hy  encroaching  tegmenal  plates.  Infrahasals  five,  excep- 
tionally  tliree.     Stern  usually  round.     Silurian  to  Lower  Carbon iferous. 

Gissocrinus  Ang.  (Fig.  317).  IB  three.  Anal  tube  compressed,  its  plates 
short,  wide  and  folded.  Distal  margin  of  brachials  usually  project.  Silurian  ; 
Gotland,  England  and  North  America. 

Cyathocrinus  Miller  (Figs.  318,  319).     Infrabasals  five.     Anal  tube  short 


a,  Gissocrimis  arthriticus  Phill.  Silurian  ;  Got- 
land. Crown  of  the  natural  size  (after  Angelin) ; 
h,  G.  punctuosus  Ang.  Tegmen  ;  c,  Ventral  and 
lateral  aspect  of  the  arms  (enlarged). 


m-^CT-^tTXTX: 


Fio.  318. 

Cyatlwcrlmis.     Analysis  of  dorsal 
cup  (after  Bather). 


Fig.  319. 

a,  Cyathocrinus  longimanus  Ang.  Silurian  ; 
Gotland.  Crown  of  the  natural  size  (after 
Angelin) ;  />,  C.  ramosus  Ang.  Portion  of  an 
arm  viewed  from  the  side  ;  c,  Ventral  aspect  of 
same  (enlarged);  d,  C.  malvaceus  Hall.  Lower 
Carboniferous  ;  Burlington,  Iowa.  Tegmen 
perfectly  preserved  ;  e,  The  same  after  removal 
of  the  covering  pieces  and  orals  (after  Meek 
and  Worthen). 


and  rounded,  or  long  with  a  valvulär  pyramid  at  distal  end ;  its  plates  more 
or  less  hexagonal,  not  transversely  elongate,  nor  much  folded.  Arms  branch- 
ing as  many  as  five  to  seven  times.  Kadial  facets  horse-shoe  shaped,  directed 
outward,  with  occasional  incipient  transverse  ridge.  Ambulacral  covering 
plates  well  developed,  regularly  alternating,  or  modified  so  as  to  resemble 
budding  pinnules.  Stem  round,  streng,  short,  apparently  without  cirri.  A 
well-known  and  widely  distributed  genus,  occurring  from  the  Silurian  to 
Lower  Carboniferous  (Warsaw) ;  Europe  and  America. 

Mastigocrinus   Bather.     Like  Cyathocrinus  in   the  structure  of   the  calyx. 


CLASSjii  CEINOIDEA  221 

but  with  longer  arms  and  anal  tube,  which  is  more  like  that  of  the  Poterio- 
crinidae,  probably  with  lateral  opening.  Stern  quinquepartite.  Silurian  ; 
England. 

Streptocrinus  W.  and  Sp.  {Ophiocrinus  Ang.  uon  Salter),  Calyx  like  that  of 
Cyathocrinus.  Anal  tube  coiled,  opening  probably  at  the  side.  Arms  branching, 
coiled  inward,  with  peculiar  processes  called  "  false  pinnules."  Not  well 
understood.     Silurian ;  Gotland. 

Lecythocrinus  Joh.  Müller  {Taxocrinus  briareus  Schultze)  (Fig.  320).  Arms 
branching  repeatedly.  Anal  tube  long,  with  strong 
plates  in  longitudinal  columns.  Stem  subquadrangular, 
with  central  and  four  peripheral  canals.  Infrabasals 
small,  unknown,  may  be  undivided.  Middle  Devonian  ; 
Eifel. 

Lophocrinus  Meyer  (Carduocrinus  Koenen).  Onlv 
one  arm  to  the  ray,  with  small  ramuli  alternating  from 
every  second  brachial.  Anal  tube  of  delicate  plates. 
Upper  Carboniferous ;  Germany. 

Codiacrinus  Schultze.  No  anal  plate  in  dorsal  cup. 
Infrabasals  three.  Radial  facets  directed  obliquely 
outward,  and  with  a  separate  dorsal  canal.  Arms 
dichotomous,  short  and  slightly  developed.  Calyx 
obconical,  expanding  upward.    Middle  Devonian ;  Eifel.  ^    .^ 

Lecythiocrinus  White.  Known  only  from  the  dorsal  LecythocnZeman...Mnn. 
cup,  which  has  the  same  elements  as  the  preceding.  Devonian;  Eifei.  Restored 
Arm    facets    directed    upward,    without  dorsal    canal. 

Calyx  bursiform,  contracting  at  the  arm  bases.  Upper  Carboniferous  ;  North 
America.  • 

Family  10.     Botryocrinidae  Batlier. 

Dicydic.  Tegmen  composed  of  irregulär  plates  without  definite  orals  or  amhula- 
crals,  extended  posteriorly  into  a  ventral  sac.  Radianal  oblique,  not  touching  basals, 
variable  in  size.  Anal  x  in  line  with  radials.  Arms  usually  heterotomous,  but 
varying  from  ramuliferous  to  complete  pinnulation.  Articulation  of  first  brachial  an 
radial  imperfect,  facets  usually  shallow,  curved,  not  as  wide  as  the  radial.  Silurian 
and  Devonian. 

Botryocrinus  Angelin  (Sicyocrinus  Ang.).  EA  small,  quadrangular.  Ventral 
sac  large,  sometimes  coiled,  with  anus  below  the  coil.  Arms  heterotomous, 
with  two  main  rami  bearing  ramules  which  in  some  species  reach  the  State  of 
pinnulation.     Silurian  and  Devonian ;  Gotland,  England  and  North  America. 

Bhadinocrinus  Jaekel.  Calyx  small,  with  very  long  ventral  sac.  Arms 
relatively  long  and  heavy,  with  ten  main  rami,  bearing  very  small,  branching 
ramules  at  long  intervals.     Lower  Devonian ;  Germany. 

Gastrocrinus  Jaekel.  Similar  small  calyx,  with  shorter  sac,  having  longi- 
tudinal columns  of  projecting  plates.  Arms  long,  with  irregulär  dichotomy. 
Stem  with  whorls  of  cirri.     Lower  Devonian ;  Germany. 

Cosmocrinus  Jaekel  (Cyathocrinus  ornatissimus  Hall).  EA  large.  Ventral 
sac  very  large,  reaching  as  high  as  the  arms.  Arms  heterotomous,  with  ten 
main  trunks  having  several  branches  nearly  as  large,  toward  the  inside  of  the 
dichotom,  which  in  turn  bear  regulär  piiuiules.  Radial  facets  rather  wide. 
Devonian  (Portage) ;  New  York. 


222 


ECHINODERMATA— PELMATOZOA 


PHYLÜM  IV 


Maragnicrinus  Whijtfield.  From  the  same  locality  and  horizon  as  the 
last;  differing  from  it  in  having  narrower  arm  facets,  the  arms  regularly 
dichotomous,  branching  once,  and  the  rami  bearing  pinnules  directly. 


Family  11.      Poteriocrinidae  Eoemer  (emend.  Wachsm.  and  Springer). 

Dicydic.  Tegmen  cornposed  of  undifferentiated  plates,  without  identifiable  orals 
or  amhulacrals ;  more  or  less  extended  into  a  ventral  sac,  with  anus  helow  the  distal 
end  on  the  anterior  side.  Union  of  radials  with  first  hrachials  usualhj  by 
muscular  articulation,  upon  straight  facets  as  wide  as  the  radial^  with  fossae, 
muscles  and  ligaments,  and  transverse  ridge  (exception  in  Poteriocrinus,  a  transition 

form).  Arms  pinnulate,  mostly  dichotomous.  Infra- 
hasals  five,  exceptionally  three,  or  coalesced  into  one. 
Stern  usually  with  cirri.     Devonian  to  Permian. 

Subfamily  A.      Poteriocrininae. 

Radianal  in  oblique  position.  Anal  x  usually  in 
line  with  radials.  Arms  usually  uniserial,  tending  to 
biserial  in  later  genera  ;  dichotomous  or  heterotomous. 
Infrabasals  usually  five.  Crown  usually  elongate, 
expanding  upward.     Stern  usually  round,  occasionally 

pentagonal.  Devonian  to 
Upper  Carboniferous. 

Poteriocrinus  Miller. 
Radial  facet  usually 
curved,  less  than  width 
of  B,  with  imperfect  or 
no  transverse  ridge. 
Arms  dichotomous, 
branching  frequently. 
Ventral  sac  large  and 
long,  usually  rising  be- 
yond  the  arms.  Stem 
usually  round,  without 
cirri,  at  least  in  upper 
part.  (?)  Devonian  and 
Lower  Carboniferous 
(Keokuk) ;  Europe  and 
North  America. 


Fig.  321. 

Pachylocrinus  unicus  Hall.  Lower 
Carboniferous  (Keokuk  Group)  ;  Craw- 
fordsville,  Indiana.     Natural  size. 


Fig.  322. 


Pachylocrinus  sp.  Analysis  of  dorsal 
cup.  a,  Anal  x;  ai,  Riglit  tube-plate  ; 
h,  Basais  ;  ib,  Infrabasals  ;  r,  Right  and 
left  posterior  radials  ;  ra,  Radianal. 


The    Devonian    species 

referred  to  this  genus  are 

probably     Parisocrinus  ; 

without    the    arms    being 

this    cannot    be 


Fig.  323. 
Pachylocrinus    aequalis    Hall. 
Lower     Carboniferous     (Keokuk 

Group);      Crawfordsville,      Ind.      

Complete  crown  from    posterior    T»rp«prvprl 
side,  showing  base  of  ventral  sac    U'^^^^y^^  ^ 

andmodeofarm-branching.  certainly  determined.    The 

genus   lacks   the  complete 
muscular  articulation  characteristic  of  the  family,  but  is  otherwise  typical. 

Pachylocrinus  Wachsmuth  and  Springer  {Scaphiocrinus  auctt.,  non  Hall  = 
Graphiocrinus ;  Hydriocrinus  Trautschold  ;  Abrotocrinus  M.  and  G.)  (Figs.  269, 
321-3).    Radial  facets  of  this  and  all  succeeding  genera  normal  for  the  family. 


CLARS  III 


CRINOIDEA 


223 


Calyx  obconic  to  low  cup-shaped.  Arms  branching  two  to  four  times,  usually 
more  or  less  dichotomous,  but  in  some  species  the  inner  arms  of  the  dichotom 
branch  less  frequently  than  the  others,  or  remain  simple,  tending  to  the  stage 
of  heterotomy  seen  in  genera  like  Zeacrinus.  Brachials  cuneiform.  Ventral 
sac  strong,  usually  enlarging  distally.  Stem 
round  or  pentagonal,  with  cirri  moderately  devel- 
oped.  Carboniferous  (Kinderhook  to  Upper  Car- 
boniferous) ;  North  America,  Europe. 

This  is  a  widely  distributed  form  known  in  collections 
generally  as  Scaphiocrinus,  a  name  wliich  lapses  because 
the  type  species  belongs  to  the  previously  established 
GrapJiiocrinus.  It  is  one  of  the  longest  lived  Paleozoic 
genera,  represented  by  a  large  number  of  species,  and  is 
highly  typical  for  this  family. 

JFoodocrinus  Koninck  (1  Philocrinus  Koninck) 
(Fig.  324).  Similar  to  preceding,  but  brachials 
Short,  quadrangular,  arms  usually  heavier  and 
branching  two  to  four  times.  Ventral  sac  stout 
and  apparently  short.  Stem  short,  tapering 
distally,  with  scattered  cirri.  Lower  Carbonifer- 
ous; England. 

Zeacrinus  Hall.  Crown  more  or  less  ovoid, 
often  short,  rounded  above  and  below.  Arms 
heterotomous,  usually  closely  abutting  and  infold- 
ing ;  the  two  outer  branches  of  each  ray  the 
stoutest,  giving  off  at  intervals  successive  pin- 
nulate  arms  of  nearly  equal  size  and  reaching  to 
the  same  height,  always  to  the  inside  of  the 
dichotom,  usually  unbranched,  but  they  may 
divide.  Brachials  short,  quadrangular.  Ventral 
sac  short,  usually  diminishing  upward.  Stem 
round,  bearing  long  cirri  distally.  Carboniferous 
(Kinderhook)  to  Coal  Measures ;  Mississippian 
area.  North  America. 

Coeliocrinus  White.  Crown  elongate,  expand- 
ing  upward,  with  conical  base.  Arms  as  in 
Zeacrinus,  but  not  so  closely  abutting,  and  with 
brachials  cuneiform  to  interlocking.  Ventral  sac 
inflated,  balloon-shaped.  Lower  Carboniferous 
(Burlington) ;  Mississippian  area.  North  America; 
also  Eussia. 

Hydreionocrinus  Koninck.  Crown  short,  flat 
above,  with  concave  base.  Arms  branching  some- 
what  as  in  Zeacrinus,  but  very  short,  not  rising 
above  the  expanded  rim  of  the  sac ;  brachials 
interlocking  to  fully  biserial.  Ventral  sac  mushroom-shaped.  Upper  part  of 
Lower  Carboniferous  (Kaskaskia)  to  Coal  Measures ;  Belgium,  Britain  and 
North  America. 

Decadocrinus  W.  and  Sp.  Calyx  depressed  and  base  flat  or  concave.  Arms 
strictly  isotomous,  branching  but  once,  giving  two  strong,  pinnulate  rami  to 
the  ray,  more  or  less  angular  or  zig-zag.     Brachials  wedge-shaped,  the  longer 


Fio.  324. 

WocHlocrinvs  macrodnc- 
tylus  (de  Koninck).  Per- 
fect  specinien  from  the 
Lower  CarlKiniferons  of 
Yorkshire  (afl.-T  <]>-  Kon- 
inck). 


224 


ECHINODERMATA— PELMATOZOA 


PHYLüM  IV 


alternating  sides  bearing  stout  pinnules  which  are  well  separated,  resembling 
ramules.  Ventral  sac  large,  often  almost  as  long  as  the  arms.  Stern  rela- 
tively  small,  sub-pentagonal,  with  rather  plentiful  cirri.  Devonian  and 
Lower  Carboniferous  (Keokuk) ;  North  America  and  Europe. 

■  Aulocrinus  W.  and  Sp.  Like  the  preceding,  but  ventral  sac  forked,  with 
anal  opening  from  a  lateral  spout.  Stern  sharply  pentagonal,  with  cirri. 
Keokuk  Limestone ;  Indiana. 

Scytalocrinus  W.  and  Sp.  Similar  to  Decadocrinus,  but  with  calyx  usually 
elongate,  more  or  less  conical  base,  arms  cylindrical,  and  pinnules  closely 
packed.  Stem  large,  round,  with  cirri  sparse  and  mostly  distal.  Devonian 
and  Carboniferous  (Goal  Measures) ;  North  America  and  Europe. 

Agassizocrinus  Shumard  ex  Troost  MS.  {Astylocrinus  Roemer)  (Fig.  325). 

Calyx  elongate,  ovoid  to  pyriform.     Arms  ten,  with  pinnules  closely  packed, 

a  as    in    Scytalocrinus ;    brachials    quadrangular,     becoming 

cuneiform    distally.      Ventral  sac   unknown.      Infrabasals 

five,  in  mature  specimens  fusing  to  a  rounded  undivided 

base.       Stem   entirely   wanting,  but  probably  present  in 

early  stages.    •  Carboniferous  (Kaskaskia  to  Coal  Measures) 

Mississippian  area  ;  North  America. 

Cromyocrinus  Trautsch.  (Figs.  326, 
327).  Calyx  rounded  below,  but  not 
concave.  IB  large,  visible  exteriorly. 
Arms  five,  or  ten,  stout,  not  branching 
beyond  the  first  axillary.  Brachials 
quadrangular  to  cuneiform,  tending  to 
become  biserial.  Ventral  sac  incon- 
spicuous.  Stem  round.  Lower  Car- 
boniferous ;  Eussia  and  Mississippi 
Valley  area. 

Ulocrinus  Miller  and  Curley.  Similar 
to  Cromyocrinus,  but  with  anal  x  entirely 
above  the  radials  ;  that  is, 
with  radianal  but  no  anal 
in  the  dorsal  cup.  Arms 
unknown.  Upper  Carbon- 
iferous ;  North  America. 

Eupachycrinus  Meek 
and  Worthen.  Similar  to 
Cromyocrinus,  but  calyx 
low,  rounded,  with  concave 
base ;  infrabasals  at  bot- 
tom  of  a  funnel.  Arms  ten  to  twenty.  Brachials  quadrangular  to  biserial. 
Stem  round,  with.  cirri.  Kaskaskia  to  Upper  Carboniferous ;  North  America 
and  Europe. 

Tribrachiocrinus  M'Coy  (Pentadia  Dana).  Calyx  globose.  Infrabasals  three, 
large.  Radials  irregulär  in  size  and  form,  apparently  only  three  arm-bearing. 
Arms  unknown.     Permo-Carboniferous  ;  Australia. 


Fig.  326. 

Cromyocrinus  globulus 
M.  and  W.  Lower  Car- 
boniferous ;  ehester,  111. 
Natural  size  (after  Meek 
and  Worthen). 


Fig.  325. 

Agassizocrinus     laevis 
(Roemer).  Kaskaskia 

Group  ;  Illinois,  a,  Com- 
plete  crown,  after  Roe- 
mer in  Bronn,  soniewhat 
restored ;  b,  Ventral  as- 
pect  of  the  coalesced 
infrabasal  disk  ;  c,  Side- 
view  of  same,  nat.  size 
(after  M.  and  W.) 


t>^. 


Fig.  327. 


Analysis  of  plates  in  the  dorsal  cup  of 
Cromyocrinus.  ib,  Infrabasals  ;  b,  Basais  ; 
r,  Radials  ;  ra,  Radianal  ;  a,  a',  a",  Anal 
and  lower  tube  plates  (after  Bather). 


CLASS  III  CRINOIDEA  225 

Subfaniily  B.     Graphiocrininae  Ballier. 

No  radianal.  Anal  x  more  or  less  between  radials.  Arms  dichotomous,  uniserial 
to  hiserial.  Infrabasals  usually  five,  frequently  minute,  liidden  hy  the  column,  Stern 
usually  round,  cirriferous.     Lower  Carboniferous  to  Upper  Carboniferous. 

Graj)hiocrinus  Kon.  (Scaphiocrinus  RaW ;  Phialocrinus  Trautschold;  Aesiocrinus 
Miller  and  Gurley)  (Fig.  328).  Calyx  low,  turbinate  or  obconic  to  bowl- 
shaped.  Infrabasals  minute  to  fair  size.  Arms 
uniserial,  usually  long,  slender,  branching  once, 
sometimes  unbranched  in  one  or  more  rays,  making 
the  number  variable  from  five  to  ten.  Bracbials 
quadrangular.  Ventral  sac  very  large  and  con- 
spicuous.  Stern  round,  with  long  cirri  throughout. 
A  genus   of    ereat   stratierraphic   ränge   and    wide  fio.  328. 

T    ,    .^      ,.  T  /TT--     11        1  \     ,        TT  i-^  Analy8isofGra;)7aocrmtt*'.  ib, In- 

distribution.       Lower    (KindernOOk)    to     Upper    Uar-    frabasals  ;&,   Basais ;  r,  Radials ; 

boniferous  ;  North  America,  Belgium  and  Russia.        Satitr).^ '    ^''   ^'*'^'^^'  ^^^^'' 

Bursacrinus  Meek  and  Worthen.     Calyx  obconic. 
Arms  rather  broad,  closely  abutting,  branching  twice  or  more,  to  some  extent 
as  in  Zeacrinus ;  uniserial,  with  quadrangular  brachials.     Ventral  sac  incon- 
spicuous.    Very  rare.    Lower  Carboniferous  (Burlington);  Mississippian  area, 
North  America. 

Delocrinus  Miller  and  Gurley  {Ceriocrinus  White,  non  Koenig).  Similar  to 
Graphioc7'inus,  but  with  concave  base,  ventral  sac  inconspicuous,  and  heavy 
biserial  arms.  Axillary  primibrach  frequently  protuberant  or  spiniferous. 
Infrabasals  at  bottom  of  a  deep  funnel,  hidden  by  column.  Stern  rather  small, 
round,  cirriferous.     Upper  Carboniferous  ;  North  America. 

Cibolocrinus  Weller.  Dorsal  cup  low,  bowl-shaped.  Infrabasals  three. 
Other  parts  unknown.     Permian  ;  Western  Texas. 

Subfamily  C.     Encrininae  Austin  (emend). 

Dorsal  cup  with  perfed  pentamerous  symmefry,  having  no  radianal  or  anal 
plate.  Arms  dichotomous,  biserial;  usually  Jieavy,  and  two  to  the  ray.  Ventral 
sac  inconspicuous  or  wanting.  Infrabasals  five,  coalesced  into  one,  or  atrophied. 
Calyx  usually  low,  bowl-shaped,  with  rounded  or  more  or  less  concave  base.  Stern 
usually  round.     Lower  Carboniferous  to  Trias. 

Stemmatocrinus  Trautschold.  Base  broadly  rounded.  Infrabasals  coalesced 
into  a  large  fTat  pentagon.  No  anal  x  nor  tube-plate  visible  in  cup.  Arms 
ten,  thick,  closely  abutting,  and  strongly  resembling  those  of  Encrinus 
liliiformis.     Lower  Carboniferous ;  Russia  and  North  America. 

Erisocrinus  White.  Base  rounded,  with  but  little  concavity.  Infrabasals 
five,  fairly  large,  not  in  a  fui^nel,  usually  visible  outside  of  the  stem.  Anal 
«  or  a  tube-plate  rests  on  the  upper  surface  of  posterior  radials.  A  close 
derivative  from  Delocrinus,  which  it  resembles  in  the  arms  and  general  form, 
difFering  in  the  base  and  absence  of  anal  plate  in  the  cup.  Upper  Carbonifer- 
ous ;  North  America. 

Encrinus  C.  F.  Schulze  (Chelocrinus,  Calathocrinus  v.  Meyer ;  Flabellocrinus 
Klipstein  ;  (?)  Cassianocrinus  Laube  ;  (?)  Traumatocrinus  Wöhrmann  ;  Porocrinus 

VOL.  I  Q 


226 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


Dittmar   non  Billings)   (Figs.    329-331).     No   anal   x  nor  tube-plate   visible. 

Calyx   low,    with  base  more   or  less   concave. 

Infrabasals  five,  minute,  concealed  in  the  basal 

concavity,  sometimes  reduced  to  three,  or  atro- 

phied.    Arms  usually  ten,  exceptionally  twenty; 

uniserial  at  their  lower  ends,  but  soon  becoming 

biserial ;  separate  axial  canal  in  radials,  extend- 

ing   into    the    arms.       Tegmen    not    definitely 

known.     Stern  round,  apparently  without  cirri. 

Abundant    in     the    Trias,     especially    in    the 

Muschelkalk  of  Germany.     The  stem  fragments 

of  E.  UlUformis  frequently  form  beds  of  marine 

limestone  (Trochitenkalk). 


This  genus  was  formerly  associated  by  the  majority 
of  European  authors  with  the  Recent  Crinoids  under  the 
Articulata.  It  was  shown  by  Wachsmuth  and  Springer 
that  its  relations  are  clearly  with  the  later  Paleozoic 
Inadunata,  and  its  position  as  such  is  recognised  by 
most  recent  writers.     The  type  species,  U.  liliiformis,  by  reason  of  its  striking  appearance 


Fig.  329. 
Diagram  sliowing  conr.se  of  axial  canals 
in  the  calyx  and  arms  of  Encrinus.  Canals 
represented  by  dotted  lines  when  pene- 
trating  tlie  interior  of  tlie  plates,  and  by 
heavy  lines  when  exposed  on  the  inner 
side  of  the  calyx  (after  Beyrich). 


Fig.  330. 

Eflicrinus  liliiformis 
Miller.  Muschelkalk ; 
Brunswick. 


Fig.  331. 
Portions  of  the  calyx  and  arms  of  Enorinus.  a,  Interior 
of  calyx ;  ai,  Exterior  of  same ;  b,  Basal,  upper  surface ; 
r,  Radial,  inner  surface  ;  ß,  One  of  the  uniserial,  and  ß*,  bi- 
serial arm-plates  ;  both  of  them  traversed  by  duplicate 
dorsal  canals ;  p,  Pinnule  ossicle  (enlarged) ;  br,  First 
brachial,  under  surface ;  br^  2,  First  and  second  brachials 
joined  togfether ;  inside,  seen  from  below  ;  br^,  First  brachial, 
Upper  surface,  showing  line  of  syzygial  suture  ;  br"^,  Second 
brachial  (axillary),  showing  articular  facets. 


and  beautiful  preservation,  early  attracted  the  attention  of  observers.     The  generic  name 
was  first  applied  in  1760  ;  and  the  form  is  the  best  known  of  all  fossil  Crinoids, 


Order  4.     ARTICULATA.     J.  S.  Miller  (emend.  J.  Müller). 

Tegmen  coriaceous,  studded  with  minute  calcareous  partides,  which  may  l 
invisible  externally,  or  may  he  entarged  into  well-defined  plates  that  rarely  form  a 
complete  investment.  Mouth  and  food  grooves  exposed,  but  often  hordered  with  one 
or  two  rows  of  side  and  covering  plates  capahle  of  heing  closed  down  over  them. 
Orals  present  in  the  young,  often  also  in  the  adult.     Plates  of  the  dorsal  cup,  except 


CLASS  III  CRINOIDEA  227 

in  pelagic  forms,  massive,  and,  except  in  (he  pelagic  forms,  much  reduced  in  size. 
Radiais  and  arm-plates  perforated  hy  separate  dorsal  canal.  Base  in  most  cases 
adually  or  potentially  dicyclic ;  the  infrabasals,  and  sometimes  also  the  hasals, 
heilig  often  atrophied,  radically  altered  hy  resorption  and  subsequent  rehuilding,  or 
ahsent  altogether. 

Proximal  columnal  always  modified,  usually  enlarged,  attached  to  the 
calyx  by  close  suture,  to  the  columnal  below  it  also  by  close  suture  (the 
so-called  stem-syzygy) ;  but  this  pair  of  columnals  in  some  forms,  instead 
of  maintaining  the  original  connection  with  the  calyx,  is  separated  from  it 
by  varying  intervals  in  the  stem,  or  at  least  in  its  proximal  portion.  Union 
between  the  plates  of  the  dorsal  cup  is  by  close  suture,  between  the  radials 
and  the  primibrachs  by  muscular  articulation,  and  between  the  elements  of 
the  primibrach  series  by  non-muscular  articulation.  Eadials  always  in  lateral 
contact.  Radianal  and  anal  plates  may  be  represented  as  such  in  the  larval 
stages,  but  never  in  the  adult ;  and  the  anal  occasionally  develops  into  a  sup- 
plementary  radial,  bearing  a  typical  post-radial  series  indistinguishable  from 
those  on  the  other  radials.  Arms  uniserial  and  pinnulate,  though  the  basal 
pinnulation  is  often  defective.  No  concavity  in  the  apex  of  the  dorsal  cup 
for  the  reception  of  the  stem.  Stem  reduced  to  a  single  columnal  in  the 
Comatulid  division  of  this  order.     Lias  to  Recent. 

In  the  earlier  German  and  English  editions  of  this  work,  following  the  example 
of  previous  European  authors  generally,  the  Mesozoic  and  Recent  Crinoids  (excepting 
Marsupites,  Uintacrinus,  and  perhaps  Encrinus)  were  treated  as  a  distinet  group  from 
the  Paleozoic  under  the  name  Articulata,  proposed  by  J.  S.  Miller  for  the  Apiocrinidae, 
Encrinidae  and  Pentacrinidae,  and  extended  by  Johannes  Müller  to  include  the 
Comatiüids.  The  chief  characters  relied  upon  to  distinguish  the  order,  viz.  (1)  «n 
open  mouth  and  food  grooves,  (2)  a  separate  axial  or  dorsal  canal  perforating  the 
arms,  were  admittedly  indecisive,  considering  that  the  first  belongs  eqiially  to  the 
entire  Paleozoic  groiip  Flexibilia,  and  the  second  is  shared  by  a  Devonian  family  and 
several  genera  of  the  Inadunata. 

This  evident  inadequacy  of  the  definition  has  led  to  various  proposed  Substitutes 
for  the  plan,  such  as  placing  the  Pentacrinidae  under  the  Fistulate  Inadunata,  and 
the  Comatulids  together  with  the  Apiocrinidae,  etc.,  as  a  subdivision  ("  Pinnata ") 
under  the  Flexibilia.  None  of  these  has  proved  satisfactory  ;  least  of  all  the  last, 
for  the  lack  of  any  sufficiently  definable  connection  between  the  so-called  Pinnata  and 
the  Paleozoic  Flexibilia.  The  very  pliant  calyx  of  the  latter  recurs  in  the  pelagic 
Comatulids,  Marsiqntes  and  Uintacrinus,  and  the  close  lateral  union  or  partial 
incorporation  of  lower  brachials  is  found  to  some  extent  among  the  Apiocrinidae, 
Pentacrinidae,  and  some  Comatulids.  But  it  has  become  increasingly  evident  that 
the  Flexibilia  were  a  specialised  group,  derived  from  the  Inadunata,  and  ending  like 
the  Camerata  with  the  Paleozoic. 

The  only  one  of  the  primary  divisions  of  the  Crinoids  that  seems  to  have  survived 
is  the  Inadunata,  the  most  generalised  type,  from  which  all  the  post-Paleozoic  forms 
are  evidently  descended.  While,  therefore,  there  is  no  valid  ground  for  any  such 
divisions  as  Paleocrinoidea  and  Neocrinoidea,  as  proposed  by  Wachsmuth  and  Springer 
and  by  Carpenter,  but  afterward  abandoned,  yet  it  cannot  be  denied  that,  with  the 
sole  exception  of  the  Triassic  Encrinus,  the  known  Crinoids  of  Mesozoic  to  Recent 
times  have  an  assemblage  of  features  by  which  they  are  broadly  distinguished  from 
their  Paleozoic  ancestors.  And  it  is  believed  that  this  may  be  expressed  under  the 
group  Articulata  as  enlarged  by  Johannes  Müller,  distinguished  not  by  any  single 
character  peculiar  to  itself,  but  by  the  fact  that  a  large  numljer  of  characters  belonging 


228  ECHINODERMATA— PELMATOZOA  phylum  iv 

to  different  groups  of  Paleozoic  Crinoids,  and  by  which  they  were  differentiated,  liave 
become  fixed  and  generally  constant  in  tliis.  It  is  by  tbe  combination  of  a  number 
of  well-marked  cliaracters,  therefore,  that  tbe  definition  of  tbis  group,  as  herein  given, 
becomes  logically  effective. 

The  results  obtained  during  recent  years  from  the  study  of  the  Crinoids  coUected 
by  a  large  number  of  deep-sea  expeditions,  have  thrown  an  entirely  new  light  upon 
the  relative  importance  of  the  Recent  and  fossil  forms,  and  have  shown  that  there  exists 
to-day  a  wealth  of  generic  and  specific  types  hitherto  quite  unexpected.  In  order  to 
call  attention  to  the  relative  importance  of  the  fossil  and  recent  types,  and  to  bring  to 
the  notice  of  paleontologists  the  work  which  has  been  accomplished  on  the  latter,  it 
has  seemed  advisable  to  include  mention  herein  of  a  considerable  number  of  Eecent 
genera.  As  the  paleontologist  is  most  directly  concerned  with  the  stalked  genera 
among  living  forms,  short  definitions  of  these  are  given ;  the  unstalked  living  genera, 
which  are  much  more  numerous,  are  mentioned  by  name  only. 

The  Pentacrinids  and  the  Comatulids  form  two  gi'oups  which  are  in  every  way 
strictly  parallel,  and  are  of  substantially  the  same  phylogenetic  value,  though  depart- 
ing  in  exactly  opposite  directions  from  the  parent  stock.  The  Pentacrinids  are 
characterised  by  excessive  stem  growth ;  the  larval  stem  is  lost  at  a  very  early  age, 
but  new  columnals  are  continuously  formed,  with  great  rapidity,  so  that  a  stem  of 
enormous  length  results.  The  distal  portion  of  this  stem  is  continually  dying  away, 
so  that  the  actual  length  of  the  stem  in  any  individual  is  but  a  fraction  of  the  entire 
length  which  has  been  formed  during  growth.  In  living  Comatulids  the  larval  stem  is 
similarly  lost ;  but  after  this  takes  place  no  additional  columnals  are  formed ;  stem 
growth  continues  within  the  single  columnal  which  remains  attached  to  the  calyx ; 
this  becomes  greatly  enlarged,  and  puts  forth  numerous  cirri.  Comatulids  may 
therefore  be  described  as  Pentacrinids  in  which  the  entire  stem  is  reduced  or  limited  to 
the  compass  of  a  single  columnal,  and  in  which  the  cirri  (when  present),  unable  to 
arrange  themselves  in  whorls  on  regularly  spaced  nodals,  are  closely  packed  together 
on  a  Single  nodal. 

.  The  genus  Thiolliericrinus  is  exactly  intermedia te  between  the  Pentacrinids  and 
the  Comatulids  ;  the  stem  is  developed  just  to  the  point  at  which  the  two  groups 
diverge,  at  that  point  ceasing  further  growth,  as  in  the  Comatulids,  but  being  retained 
as  in  the  Pentacrinids.  The  structure  of  the  stem  is  the  same  as  that  of  the  larval 
stem  of  the  Pentacrinids  and  of  the  Comatulids. 

The  Pentacrinids  and  Comatulids  are  the  dominant  Crinoid  forms  in  the  modern 
fauna.  The  latter  especially  are  extremely  numerous,  and  exist  in  a  vast  array  of 
diverse  types,  none  of  which,  however,  depart  in  any  great  degree  from  the  general 
structure  of  the  group  ;  so  that  their  Classification  necessitates  the  creation  of  numerous 
subfamilies,  families  and  higher  groups  which  are  not  systematically  comparable  to 
similar  groups  in  the  stalked  forms. 

In  Order  that  the  treatment  herein  adopted  may  be  more  easily  understood,  the 
foUowing  comparative  table  is  given,  which  shows  in  heavy-faced  type  the  names 
employed  by  P.  H.  Carpenter  in  the  Challenger  reports  and  largely  used  by  paleon- 
tologists, together  with  their  modern  equivalents. 

1.  Pentacrinus :  Isocrinus,  Cenocrinus^  Endoxocrinus,  Hypalocrinus,  Carpenterocrmus. 

2.  Extracrinus  :  Pentacrinus. 

3.  Antedon :  All  the  genera  which  were  known  to  Carpenter  now  included  in  the  families 
Zygometridae  (excepting  Eudiocrinus),  Himerometridae,  Stephanometridae,  Pontiometridae, 
Mariametridae,  Colobemetridae,  Tropiometridae,  Calometridae,  Thalassoraetridae,  Charito- 
metridae  and  Antedonidae  (excepting  Promachocrinus). 

4.  Actinometra  :  All  genera  included  in  the  Comasteridae. 

5.  Eudiocrinus  :  The  geniis  EudiocriniLs  of  the  Zygometridae,  together  with  Pentamctro- 
crinus  of  the  Pentametroerinidae. 

6.  Promachocrinus :  The  genus  Promachocrinus  of  the  Antedonidae,  together  with 
Decametrocrinus  of  the  Pentametroerinidae. 


CLARR  III 


CRINOIDEA 


229 


Family  1.     Bourgueticrinidae  de  Loriol. 

Column  without  terminal  stem  plate,  but  the  distal  portion  of  the  stem  bears  very 
numerous  radicular  cirri.  It  is  slender,  composed  of  joints  which  may  be  greatly 
elongated  with  strongly  concave  sides,  or  about  as  long  as  broad  with  strongly  convex 
sides,  or  of  any  intermediate  form  ;  but  the  articulating  surfaces  always  consist  of  a 
strong  fulcral  ridge  {which  may  be  interrupted  in  the  centre  by  the  central  canal) 
separaiing  two  large  ligamental  fossae ;  one  or  more  of  the  columnals  immediately 
Wilder  the  calyx  may  be  discoidal,- mth  plane  surfaces.  Dorsal  cup  small,  but  very 
variable  in  size  and  in  the  relative  proportions  of  its  component  plates  ;  composed  of  five 
hasals  (which  may  be  solidly  welded  into  a  single  plate),  and  {usually)  five  radials. 
Infrabasals  unknown,  probably  absent  in  the  adult.  Arms  slender,  five  or  ten ;  if 
the  latter,  two  primibrachs  are  present.  If  there  are  four,  six,  or  more  radials,  one 
arm  follows  each  radial.     Cretaceous  to  Recent. 


Bourgueticrinus  d'Orb.  (Fig.  332).     Basais  not  fiised.     Radials  five ;  lower 
brachials  laterally  connected.     Proximal  columnal  round,  as  wide  as  the  calyx 


Fig.  332. 

Bourgueticrinus  ellipti- 
cus  Miil.  White  Clialk ; 
Wiltshire.  a,  Calyx  with 
stem-joints,  i/i ;  5,  Ventral 
aspect,  enlarged  ;  c,  Stem- 
joints  ;  d,  Articular  sur- 
face  of  stem  -Joint ;  e, 
Girr  US. 


Fig.  333. 
Rhizocrinus  pyriformis  (Goldf.).      Eocene  ;   Verona. 
a,  h,  Calyx  from  one  side  (nat.   size  and  enlarged); 

c,  Same  from  above,  with  three  of  the  Br  in  place; 

d,  Median  longitudinal  section  of  calyx,  Vi  5  e,  Calyx 
with  slightly  abraded  outer  surface,  showing  suture 
lines  between  B  and  R  ;  f,  Calyx  with  five  rays,  seen 
from  above  (enlarged) ;  g-k,  Stem-joints,  i/i. 


at  its  greatest  breadth,  those  below  it  diminishing  for  one  or  two  joints  and 
becoming  compressed,  with  elliptical  Joint  faces,  each  columnal  twisted  so  that 
one  end  Stands  at  an  angle  to  the  other.  ^  Cirri  present  distally,  or  perhaps  in 
middle  of  the  stem.     Cretaceous  ;  Europe  and  Alabama. 

Mesocrinus  P.  H.  Carpenter.  Proximale  small  and  circular ;  otherwise  like 
Bourgueticrinus.     Cretaceous  ;  Sweden  and  Germany. 

(?)  Dolichocrinus  de  Loriol.  Radials  form  an  elongate  tube.  Upper  Jur- 
assic ;  Europe. 

Rhizocrinus  Sars  (Gonocrinus  d'Orbigny,  non  Troost)  (Fig.  333).  Basais  com- 
pletely  fused,  forming  a  very  large  and  elongate  base ;  radials  very  small,  four 
to  seven  (usually  five  or  six)  ;  arms  undivided ;  column  slender,  composed  of 
greatly  elongated  segments  of  which  the  distal  bear  radicular  cirri.  Cretaceous  ; 
New  Jersey.     Eocene  ;  Europe.     Recent ;  north  Atlantic. 

Bythocrinus  Döderlein.  Similar  to  Rhizocrinus,  but  with  the  basals  separated 
by  distinct  sutures ;  radials  (and  arms)  invariably  five.  Recent;  in  tropical 
Atlantic,  and  western  Indian  Oceans.  ,•    i  •    i 

Democrinus  Perrier.     Similar  to  Rhizocrinus,  but  with  the  base  subcylmdrical , 


230 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


the  basals  being  separated  by  distinct  sutures ;  columnals  very  short,  but 
little  longer  than  broad,  more  or  less  barrel  or  bead  shaped ;  radials  (and 
arms)  invariably  five.     Recent ;  tropical  Atlantic  and  East  Indies. 

Bathycrinus  Wy  v.  Thomson  {Illycrinus  Danielssen  and  Koren ;  Pterocrinus 
Wyv.  Thomson).  Essentially  similar  to  Bhizocrinus,  but  with  ten  arms,  each 
post-radial  series  dividing  on  the  second  ossicle ;  basals  usually  much  reduced, 
forming  a  narrow  ring  beneath  the  much  larger  radials.  Recent,  chiefly  occur- 
ring  at  great  depths,  cosmopolitan. 

Monachocrinus  A.  H.  Clark.  Similar  to  the  preceding,  but  with  the  basals 
separated  by  distinct  sutures,  and  usually  nearly  or  quite  as  large  as  the 
radials,  sometimes  larger.  Lower  Muschelkalk ;  near  Rovegliana.  Recent ; 
East  Indies,  Bay  of  Bengal,  east  Atlantic. 

Family  2.     Phrynocrinidae  A.  H.  Clark. 

Similar  in  general  to  the  Bourgueticrinidae,  but  with  the  stem  attaehed  to  a  heavy 
terminal  stem-plate  (dorsocentral)  as  in  the  Apiocrinidae.     Recent. 

Here  are  placed  the  two  genera  Naumachocrinus  and  Phrynocrinus  Clark, 
occurring  at  depths  of  from  500  to  650  fathoms  in  the  Pacific  Ocean.  The 
former  of  these  has  a  calyx  superficially  resembling  that  of  Democrinus,  but 
composed  of  very  small  basals  and  much  elongated  radials. 


Family  3.     Apiocrinidae  d'Orbigny. 

Column  without  cirri ;  enlarged  distally  and  attaehed  to  a  heavy  terminal  plate, 
or  fixed  root ;  composed  of  short ^  discoidal  columnals  having  their  articular  faces 
marJced  with  radiating  Striae  without  fulcral  ridge ;  those  next  below  the  calyx  often 
increasing  greatly  in  width,  forming  a  proximal  enlargement  continuous  with  the  sides 

of  the  calyx.      In  the  more 


Fig.  334. 


specialised  types  the  proximal  colum- 
nals may  become  penfagonal  or 
stellate,  and  may  bear  rudimenfary 
cirri.  Calyx  variable,  composed  of 
heavy  plates.  Infrabasals  greatly 
reduced,  modified  or  fused  with  the 
proximal  columnal ;  visible  rarely 
within  the  basal  ring  {cryptodicyclic). 
Lower  brachials  more  or  less  incor- 
porated  in  the  calyx  by  lateral  union, 
or  by  a  few  interbrachial  plates. 
Primibrachs  two ;  arms  branching 
regularly,  usually  more  than  once. 
Jura,  Cretaceous  and  Recent. 


Ran- 


Apiocrinus  parlcinsoni  Schlotheim.      Great  Oolite 
ville,  Calvados,     a,  Calyx  and  upper  stem-joints,  viewed  froin 
the  side ;  h,  Ventral  aspect ;  c,  Articular  surface  of  one  of  the 
stem-joints  (natural  size). 


Apiocrinus  Miller  (Figs.  334- 
336).  Plates  of  calyx  greatly 
thickened,  especially  at  the  distal 
border  of  the  radials,  where  the  typical  muscular  articulation  is  modified 
by  an  enormous  enlargement  of  the  dorsal  ligamental  fossa,  consequent  upon 
such  thickening ;  thh  expansion  afFects  in  addition  to  the  calyx,  a  series  of 
the  Upper  columnals,   and  of   the  lower   brachials.     Calyx  in  typical  forms 


CLASS  III 


CEINOIDEA 


231 


pyriform,  attaining  a  large  size,  with  proximal  columnals  flush  with  the 
curvature  of  its  sides  ;  in  some  others  globose,  with  little  enlargement  of 
the  column.  Upper  face  of  the  proximale  marked  by  angular  ridges  corre- 
sponding  to  the  iiiterbasal  suture  lines.  Radial  facets  wide,  curved, 
occupying  entire  distal  face  of  plate.  Primibrachs  two,  united  by  incom- 
plete  syzygy,  closely  joined  laterally  by  suture,  or  occasionally  connected 
by  small  interbrachial s ;  axillary  and  succeeding  brachials  united  by  muscular 


Fia.  335.  Fig.  336. 

Fig.  335. 
Ainocrinus  parkinsoni  Scliloth.  Great  Oolite  ;  Ranville,  Calvados.  A,  Analysis  of  calyx,  showing  conrse 
of  canals.  These  are  represented  by  dotted  lines  when  concealed  within  the  plates,  and  by  heavy  lines  where 
visible  on  the  inner  surface  of  the  basals.  B,  Median  longitudinal  section  throngh  the  uppeniiost  stem-joints, 
showing  empty  Space  included  between  them  ;  &,  Basal,  seen  fromabove  and  from  the  iiiside  ;  h*,  Lower  surface 
(jfsame  ;  ri,  Radial,  seen  from  without;  ri*,  Inner  aspect  of  same ;  r^!,  and  r'^*,  Corresponding  views  of  first 
brachial ;  br,  Arm-plates.  (Canals  are  invisible  in  plates  above  the  basals,  except  where  they  have  become 
exposed  by  weathering  or  abrasion.) 

Fi(i.  336. 
Ainocrinus  roissyanus  d'Orh.     Upper  Jura  (Coral- Rag) ;  Tonnerre,  Yonne.     Restoration  (after  d'Orbigny). 


articulation,  and  all  perforated  by  an  axial  canal,  Arms  dichotomous, 
branching  two  or  three  times,  pinnules  strong.  The  column  has  a  large  opeii 
Space  in  the  expanded  portion  next  to  the  calyx,  the  columnals  sloping  to  a 
thin  edge  toward  the  centre.     Jurassic ;  England,  France  and  Switzerland. 

Millericrinus  d'Orb.  (Ceriocrinus  and  Pomatocrinus  Desor,  ex  Koenig).  Closely 
allied  to  Apiocrinus,  but  the  swelling  of  calyx  plates  afFects  only  one  or  two 
columnals,  and  not  any  brachials,  nor  the  distal  border  of  the  radials,  which 
remains  narrow,  so  that  the  muscular  articulation  is  of  the  usual  type. 
Calyx  usually  more  or  less  globose  or  campanulate.     Base  occasionally  with 


232  ECHINODEEMATA— PELMATOZOA  phylum  iv 

five  minute  infrabasals  coalescedwith  the  top  stem-joint,  which  is  frequently 
widened  and  those  below  it  not  usually  so.  Column  more  or  less  pentagona!, 
with  the  angles  directed  interradially.     Lias  to  Lower  Cretaceous ;  Europe. 

Guettardicrinus  d'Orb.  DifFers  from  Apiocrinus  only  in  having  strong 
interbrachial  plates  between  the  lower  brachials,  and  the  consequent  incor- 
poration  in  the  cup  of  a  greater  number  of  secundibrachs.  Upper  Jurassic ; 
Europe.  This  and  the  two  preceding  genera  shade  into  one  another  without 
any  sharp  differentiation. 

Dadocrinus  Meyer.^  Calyx  conical,  of  small  size.  Column  sharply 
pentagona!  proximally,  becoming  round  below,  without  cirri ;  proximal 
columnal  much  smaller  than  the  calyx.  Primibrachs  sometimes  more  or  less 
connected  by  small  interbrachials.     Arms  branching  once.     Trias ;  Europe. 

Holocrinus  Jaekel.     Trias  ;  Germany. 
■  Achrochordocrmus  Trautschold  {Cyclocrinus  d'Orh.,  non  Eichw.;  Mespilocrinus 
Quenst.,  non  Koninck).     Jura  and  Lower  Cretaceous  ;    Europe.      Columnals 
only  are  known. 

Proisocrinus  A.  H.  Clark.  Rudimentary  cirri  on  proximal  portion  of  the 
column ;  proximal  columnals  with  crenulate  edges ;  division  series  very 
broad,  in  lateral  contact.     Recent ;  Philippines,  940  fathoms. 

Carpenterocrinus  A.  H.  Clark.  No  trace  of  cirri ;  proximal  columnals  with 
smooth  edges ;  division  series  narrow,  exposing  large  perisomic  areas. 
Recent ;  southern  Japan,  565  fathoms. 

Family  4.     Pentacrinidae  Gray  (emend.). 

:  Column  either  very  long,  pentagonal  or  suhpentagonal,  without  any  terminal  plate, 
and  cirriferous;  or  represented  hy  a  Single  plate,  also  usually  cirriferous ;  in  very 
young  stages  similar  to  the  stem  of  Rhizocrinus,  hut  later  discarded ;  the  portion 
retained  in  the  adult  of  sessile  forms  is  composed  of  columnals  which  have  the  upper 
and  lower  faces  'ornamented  with  a  more  or  less  complex  quinquelobate  figure.  Calyx 
small,  howl-  or  plinth-shaped,  with  a  dicyclic  base,  at  least  in  the  young,  hut  the 
infrabasals  either  rudimentary  or  completely  resorbed  in  the  adult  state ;  and  the 
basals  may  be  also  resorbed  and  metamorphosed  into  a  curious  rosette-shaped  plate 
lying  entirely  within  the  calyx.  Infrabasals  {where  observed)  three  or  five ;  basals 
five ;  radials  five  {one,  the  left  posterior,  sometimes  much  smaller  than  the  others). 
Primibrachs,  or  costals,  one  to  eight  {usually  two).  Tegmen  fiexible,  studded  with 
small  irregulär  calcareous  pa,rticles  or  delicate  plates  which  may  be  quite  invisible  to 
the  naJced  eye,  or  may  form  a  solid  covering.  Arms  pinnulate ;  strong,  from  five 
simple,  to  two  hundred  and  fifty  or  more  ultimate  branches.     Trias  to  Recent. 

Section  A.     Pentacrinids  Gray  (emend.). 
Column  persistent  throughout  life. 

Pentacrinus  Blumenb.  {Extracrinus  Austin  ;  Polycerus  Fischer  pars ;  1  Chlado- 
crinus  Agassiz)  (Fig.  337).  IBB  well  developed.  BE  usually  prolonged 
over  the  proximal  columnals.  There  are  rarely  more  than  two  IBr,  not  bearing 
pinnules.  Arms  heterotomous,  with  two  to  four  rami,  branching  only  toward 
the  inside  of  the  dichotom,  into  large  subordinate  pinnulate  ramules  which 
rise  to  the  height  of  the  main  rami,  until  the  final  divisions  are  all  about  the 
same  size ;  these  divisions  are  very  numerous,  in  mature  specimens  as  many 
as  forty  or  fifty  to  the  ray.     Column  more  or  less  pentangular ;  the  angles 


CLA.SS  III 


CRINOIDEA 


233 


of  the  axial  canal,  contrary  to  the  general  rule  in  dicyclic  forms,  directed 
radially,  corresponding  with  the  outer  angles  of  the  stem.  Stern  of  great 
but  unknown  maximum  length,  having  been  traced  for  twenty  feet  without 
reaching  the  end ;  cirri  very  numerous,  compressed  or  elliptical  in  section. 
Lias  and  later  Jura  ;  Europe. 

The  Crinoids  of  this  geiius  were 
very  gregarious,  and  flourished  in 
immense  colonies.  Exquisitely  i)re- 
served  specimens  are  found  in  the 
Lower  Lias  of  Lyme  Regis,  Eng- 
land, and  in  the  vicinity  of  ßoll 
and  Metzingen,  Würtemberg,  which 
have  served  as  types  of  illustra- 
tions  in  numerous  works  on  Paleon- 
tology.  A  slab  containing  no  less 
than  twenty-seven  perfect  crowns 
intertvvined  with  stems  and  cirri, 
raay  be  seen  in  the  U.S.  National 
Museum  at  Washington. 

Isocrinus  Meyer  {Isis  Linn. 
pars;  Encrinus  hsunsirck  pars ; 
Cainocrinus  Forbes ;  Ficteto- 
crinus  de  Loriol ;  Neocrinus 
Wy  V.  Thomson  ;  Pentacrinus 
sensu  P.  H.  Carpenter).  IBB 
so  far  as  known,  present  in 
the  adult,  but  visible  only 
when  stem  is  removed.  BB 
forming  a  complete  circlet, 
or  minute  and  separated  by 
lower  angles  of  BE.  Eadials 
notprojecting  down  ward  over 
proximal  columnals.  Arms 
about  regularly  dichotomous. 
Columnals  of  circular,  penta- 
gonal  or  stellate  section  ; 
sectors  of  joint-face  distinctly 
petaloid,  with  coarsely  crenu- 
late  edges.  Trias  and  Juras- 
sic;  Europe  and  North 
America.  Eecent  ;  "West 
Indies  (5-531  fathoms). 

Balanocrinus    Agassiz    in 
Desor.    Columnals  of  circular 
or  hexagonal  section,  with   crenellae  around  the  edge  only,  not  along  the 
sides  of  the  sector.     Trias  to  Eocene ;  Europe.     Known  from  fragments  only. 

Austinocrinus  de  Loriol.  Columnals  have  a  Joint  surface  as  in  Isocrinus, 
but  with  finer  Striae  radiating  from  the  petals.     Cretaceous  ;  Europe. 

Cenocrinus  Wyv.  Thomson.     Recent ;  West  Indies  (5-531  fathoms). 

Endoxocrinus  A.  H.  Clark  (Diplocrinus  Döderlein).  Infrabasals  resorbed 
in  the  adult.  Arms  heterotomous,  in  two  main  rami  with  branches  to  the 
inside  of  the  dichotom ;  the  divisions  are  at  the  outer  side  of  the  rays  only, 
and  consist  each  of  two  joints,  united  by  syzygy.     Kecent ;  West  Indies. 


Fig.  837. 
Pentacrinus  (Extracrinus)  fosfdlis  Blum.   Lower  Lias ;  Lyme  Regis, 
England  (after  Goldfuss).    a,  Stem-joints  of  P.  subangularü  Mill. 
Upper  Lias  ;  b,  Column  of  P.  hascUtiformis  Mill.    Middle  Lias. 


234  ECHINODERMATA— PELMATOZOA  phylum  iv 

Metacrinus  P.  H.  Carpenter.  Arms  dichotomous,  multibrachiate ;  IBr 
four  to  eight  in  number.  The  distal  portion  of  the  arms  bears  only 
rudimentary  pinnules.     Recent ;  Pacific  Ocean. 

Hypalocrinus  A.  H.  Clark.  Ten  arms  only,  unbranched ;  IBr  two.  The 
distal  portion  of  the  arms  bears  only  rudimentary  pinnules.  Recent;  East 
Indies. 

Comastrocrinus  A.  H.  Clark.  Resembles  the  preceding,  but  with  more 
than  ten  arms,  and  with  the  distal  edges  of  the  brachials  strongly  produced. 
Recent;  Indian  Ocean. 

Section  B.     Thiolliericrinids  A.  H.  Clark. 

Column  persistent  throughout  life;  hut  columnar  development  ceases  after  the 
formation  of  the  first  nodal. 

Thiolliericrinus  Etallon.  Column  resembling  that  of  the  pentacrinoid 
larvae  of  the  Comatulids,  but  greatly  enlarged  and  thickened ;  calyx  as  in  the 
adult  Comatulid.     Jurassic  and  Cretaceous  ;  Switzerland,  France,  Portugal. 

The  genus  Thiolliericrinus  has  been  considered  both  as  representing  a  primitive  Comatulid, 
and  a  transitional  stage  between  the  Apiocrinidae  and  the  Pentacrinidae  ;  but  neither  view 
is  correct.  The  column  of  Thiolliericrinus  is  comparable  to  that  of  a  Comatulid  or  of  a 
Pentacrinid  at  the  time  of  the  formation  of  the  centrodorsal  or  of  the  first  cirriferous  nodal ; 
stem  development  has  here  abruptly  ceased,  so  that  the  column  has  retained  its  primitive 
Bourgueticrinoid  character,  modified  only  by  an  increase  in  size  ;  but  the  calyx  has  continued 
to  develop  so  as  to  be  comparable  to  the  calyx  of  the  Comatulids,  or  to  the  calyx  of  the 
more  advanced  aniong  the  Pentacrinids.  Thus  Thiolliericrinus  possesses  the  calyx  structure 
of  the  adult  Pentacrinid  or  Comatulid,  combined  with  the  column  structure  of  the  larvae  of 
the  same  types.     It  therefore  falls  naturally  between  them. 

Section  C.     Comatulids  Fleming  (emend.).i 

Column  either  wanting  entirely,  or  discarded  after  the  formation  of  the  first 
nodale  which  remains  permanently  attached  to  the  calyx. 

While  the  Comatulids,  as  already  explained,  forin  a  group  strictly  comparable  in 
phylogenetic  value  with  the  Pentacrinids  and  Thiolliericrinids,  this  group  is 
wholly  disproportionate  to  those  in  complexity  and  extent.  Owing  to  their  enormous 
and  cosmopolitan  development  in  Recent  seas,  the  Comatulids  require  for  their 
Classification  further  subdivision  in  a  way  not  applicable  to  any  of  the  fossil  families. 
The  group  must  therefore  be  taken  as  a  new  unit,  divisible  into  subgroups  which  are 
comparable  in  rank  only  inter  se,  and  not  with  subdivisions  of  similar  grade  or 
terminology  among  the  other  Crinoids. 

Tribe  1.     Innatantes  A.  H.  Clark. 

Pelagic  Comatulids  in  which  the  basals  are  not  metamorphosed  hut  form  an 
integral  part  of  the  hody  wall ;  the  infrahasals  are  not  united  with  the  central  plate, 
but  frequently,  through  individual  Variation,  they  are  absent.  There  is  no  evidence  of 
attachment  in  any  hnown  material,  so  that  their  central  apical  plate  probably  repre- 

^  Literature  :  Müller,  J.,  lieber  die  Gattung  Comatula,  etc.  Abhandl.  Berlin.  Akad.  1847. — 
Ludwig,  H.,  Beiträge  zur  Anatomie  der  Crinoidea.  Zeitschr.  wiss.  Zool,  vol.  xxviii.  1877. — 
Carpenter,  P.  H.  Report  on  the  Crinoidea.  Sei.  Eesults  Ghali.  Exped.,  xi.  and  xxvi.,  1884-88. — 
Jaekel,  0.,  Entwurf  einer  Morphogenie  und  Phylogenie  der  Crinoideen.  Sitzber.  naturf.  Ges.,  1894. 
— Clark,  A.  H.,  See  titles  cited  under  general  discussion. 


CLARS  III 


CRINOIDEA 


235 


I 


sents  the  Single  columnal  of  Comatulids  and  the  entire  stem  of  the  Pentacrinids. 
The  calyx  is  very  large,  and  its  plates,  which  are  very  tJiin,  are  strongly  curved  out- 
wardly.     Cretaceous. 


Subtribe  A. 


Marsupitids  d'Orbigny. 

Column  wanting,  probably  represented  hy  a  large  pentagonal  plate  called  the 
centrale,^  within  the  infrabasal  circlet.  Calyx  large,  perfedly  pentamerous,  composed 
of  large  thin  plates,  without  interradials  or  anals  ;  greatest  bulk  below  radials.  Base 
dicyclic  plus  the  centrale,  one  of  the  largest  plates  in  the  calyx.  Infrabasals  five, 
very  large.  Radial  facets  narrow,  crescentic,  with  a  perforated  transverse  ridge. 
Lower  brachials  much  less  than  the  width  of 
the  radials,  connected  for  a  short  distance 
by  interbrachials,  but  not  strictly  incorpor- 
ated  in  the  dorsal  cup.  Primibrachs  two, 
narrow.  Arms  small,  apparently  short, 
with  slender  pinnules  ;  bifurcation  on  the 
second  primibrach,  further  branching  un- 
known.     Tegmen  unhiown. 

The  only  known  genus  is  Mar- 
supites  Miller  (ex  Mantell  MS.),  occur- 
ring  in  the  Upper  Cretaceous  (White 
Chalk)of  England,  France  and  Northern 
Germany,  and  in  the  Tombigbee  Sand- 
stone of  Northern  Mississippi.  Its 
general  structure  is  on  the  Inadunate 
plan,  with  remarkable  development  of 
the  basal  portion,  the  infrabasals  and 
centrale  constituting  about  half  of  the  entire  calyx  (Fig.  338), 


ii 


Fig.  338. 


Marsupiteji  testudinarius  (Schloth).  Upper  Cre- 
taceous ;  Lüneburg,  Prussia.  a,  Calyx,  natural  size ; 
h,  Radial,  and  a  few  of  the  arm-plates  ;  <",  Tips  of  arms. 


Subtribe  B.     Uintacrinids  Zittel. 

Column  wanting.  Calyx  large,  perfedly  pentamerous,  greatest  bulk  above  line 
of  radials,  plates  thin;  interbrachial  system  greatly  developed.  Base  dicyclic  m' 
monocyclic ;  infrabasals  present  or  absent  in  both  young  and  adult  of  the  saine 
species  ;  when  present,  five  (but  sometimes  by  resorption  reduced  irregularly  to  three, 
two,  or  one),  very  small,  enclosing  a  small  centrale,  probably  representing  the  stem  ; 
when  absent,  the  centrale  remains  of  about  the  same  size,  surrounded  by  the  basals. 
Interbrachials  numerous,  from  the  radials  up,  and  often  also  in  the  second  axil. 
Primibrachs  two,  as  large  as  the  radials  ;  the  second  one  axillary,  followed  by  secundi- 
brachs  almost  as  large,  passing  gradually  into  free  arms.  Arms  ten,  unbranched, 
very  long  and  strohig  ;  composed  of  very  short,  almost  circular  brachials,  with  frequent 
syzygies,  Joint  faces  provided  with  transverse  ridge,  and  pierced  by  an  axial  canal. 
Pinnules  stout  and  tapering,  the  lower  ones  incorporated  into  the  calyx  by  lateral 
Union.  Tegmen  composed  of  a  carbonaceous  skin  becoming  black  in  the  fossil  State, 
traversed  by  uncalcißed  ambulacra ;  mouth  marginal;  anus  subcentral,  through  a 
sfrong,  tufted  tube. 

^  This  plate  is  supposed  by  Carpenter  to  represent  the  distal  plate  of  the  stem,  and  not  the 
proximal.  A.  H.  Clark  believes  it,  and  the  similarly  situated  plate  in  Uinfacnnns,  to  be  the 
honiologues  of  the  distal  stem-plate,  plus  all  the  columnals  of  young  liecent  Comatulids. 


236  EOHINODERMATA— PELMATOZOA  phylum  iv 

Represented  by  a  single  genus,  Uinfacrinus  Glrinnell  (Fig.  339),  occurring 
in  the  Upper  Cretaceous  of  Western  America  (especially  Kansas),  England 

and  Westphalia.  In  the  latter 
areas  it  is  widely  distributed, 
accompanied  by  Marsupifes 
and  Bourgueticfinus.  In  the 
Kansas  region  it  is  found  ex- 
clusively  in  colonies  which 
had  been  herding  together  in 
deep  water.  The  genus  in  its 
calyx  structure  is  a  survival 
of  the  Flexibilia  plan ;  it  is 
strongly  in  contrast  with 
Fig.  339.  MarsupUes  in  this,  and  in  the 

üintacrinus  westphalicns  (Schlüt.).     Upper  Cretaceous ;  Reck-    length  of    the    arms,    which   in 
lingshausen,  Westphalia.     a,    Calyx    viewed    from   the    slde ;    h,  ^  •  j.^    •        i 

Inferior  aspect.    Natural  size  (after  Schlüter).  Hiature    specimens    attamed    a 

length  of  four  feet,  giving 
when  outstretched  a  spread  of  upwards  of  eight  feet,  the  largest  known 
Crinoid. 

Tribe  2.     Oligophreata  A.  H.  Clark. 

Bottom-inhaUting  Comatulids,  stalked  when  young ;  hasals  metamorphosed  into 
a  rosette  ;  infrahasals  unknown  ;  cavity  in  the  centrodorsal  containing  the  chamhered 
organ,  and  overlying  structures  very  small,  these  being  pushed  up  more  or  less  within 
the  radial  circlet ;  disk  more  or  less  studded,  or  even  completely  covered,  with  large 
calcareous  concretions  or  plates'/  pinnules,  at  least  the  lower,  wholly  or  in  pari 
prismatic,  and  composed  of  short  segments  ;  usually  more  than  ten  in  numher. 

Generic  names  have  been  applied  to  fossil  Comatulids  belonging  to  this 
division,  but  the  specimens  upon  which  they  are  based  are  rarely  well  enough 
preserved  to  admit  of  correlation  with  generic  names  based  upon  Recent  types. 
The  latter  include  a  surprisingly  large  number  of  living  genera,  which  are 
grouped  by  A.  H.  Clark  in  nearly  a  dozen  difTerent  families.  Among  these 
may  be  mentioned  the  Comasteridae,  Zygometridae,  Thalassometridae  and 
Charitometridae  as  examples. 

Tribe  3.     Macrophreata  A.  H.  Clark. 

Bottom-inhaUting  Comatulids,  stalked  when  young  ;  hasals  usually  metamorphosed 
into  a  rosette  ;  infrahasals,  three,  or  more  usually  five,  in  numher,  have  heen  deteded 
in  the  young  of  several  species,  where  they  fuse  with  the  centrodorsal ;  cavity  in  the 
centrodorsal  containing  the  chamhered  organ  and  associated  structures  large  ;  tegmen 
naked,  or  studded  with  minute  plates  which  may  hecome  grouped  in  the  interradial 
angles,  particularly  hetween  the  IBr ;  pinnules  all  cylindrical  or  more  or  less 
flattened,  slender,  with  very  long  Joint s  ;  arms  five  or  ten  in  numher,  except  in  the 
genera  in  which  there  are  ten  radials,  in  which  they  may  he  twenty. 

Within  this  category  are  embraced  three  divisions — Atelecrinidae  (Bather), 
Pentametracrinidae  (Clark)  and  Antedonidae  (Norman) — the  last-named  of 
which  is  again  divided  into  a  number  of  groups  having  the  rank  of  sub- 
families.     One  of  them,  Antedoninae,  includes  the   Recent  genera   Antedon 


CLASS  III 


CEINOIDEA 


237 


Freminville    {Ganymeda    Gray;    Hihemula   Fleming;    Fhytocrinus   Bio)   (Fic 
283) ;  Conipsometra,  Toxometra  and  Iridometra  A.  H.  Clark,  etc. 

Fossil  Comatulid  Genera. 

The  following  genera  are  based  wholly  or  in  part  upon  fossil  Comatulids  : 
^/W  Michelotti;^5W^/,s   Schlotheim;  Astrocoma  Blainville;    Comaty. 
d  ürbigny  ;  Comatuhthes 


von  Schlotheim;  Comaturella 
Münster;  DecacnemosBvonn ; 
Decameros  d'Orbigny,  Geo- 
coma  0.  Fraas;  Glenotremites 
Goldfuss;  J^er/Ä^Hagenow; 
Microcrinus  Emmons ;  Ophi- 
■urites  von  Schlotheim ;  Ftero- 
coma  L.  Agassiz ;  Solanocrinus 
Goldfuss  (Fig.  340). 

The  specimens  upon 
which  the  type  species  of 
these  genera  are  founded  are 
rarely  well  enough  pre- 
served  to  admit  of  reference 
to  any  one  of  the  Eecent 
genera,  or  even  families,  and 
in  some  cases  it  is  doubtful 
whether  they  are  Coma- 
tulids at  all.  P.  H.  Car- 
penter  attempted  to  differ- 
entiate  the  fossil  types  into 
Antedons  and  Aäinometras  ; 
but  recent  discoveries  have 
shown  that  the  endocyclic 
and  exocyclic  forms  are 
by  no  means  easy  to  dis- 
tinguish,  even  with  perfect 
specimens,   and   with    even 


'vt^'M 


srjki 


',,^0mik 


^ms:::!^-"^ 


W^'    '<;s>^,.„ 


w  ■=' 


■•»t~t 


^. 


# t 


Fig.  340. 


a,  Solanocrinus  costatus  Goldf.     Upper  Jura  (Diceras-Kalk);  Kel- 
heim,  Bavada.     Dorsal  aspeet  of  crown ;  centrodorsal  and  pinnules 
not  preserved  (slightly  reduced) ;  h-d,  S.  scrdbicvlatus  Goldf.     Upper 
the     best     preserved    fossils    '^"^''^  '■>  Streitberg,  Franconia ;    b.  Ventral ;   c,  dorsal ;  and  rf,  lateral 
.  .    ,  .         aspeet  of  calyx ;  e,  Arni-plate. 

the  Separation  of  the  species 

on  this  basis  is  very  unsatisfactory.  A  common  method  of  procedura  in 
dealing  with  fossil  Comatulids  has  been  to  refer  them  all  (except  those  with 
five  arms,  all  of  which  belong  to  the  genus  Eudiocrinus  of  the  Zygometridae) 
to  a  Single  genus,  for  which  the  name  Solanocrinus  is  used. 


Family  5.     Plicatocrinidae  Zittel. 

Basal  circlet  funnel-shaped,  quadrangidar,  pentagonal  or  hexagonal,  composed  of 
three  (usitalhj),  or  five  basals  which  may  he  solidly  anchylosed.  Radiais  four,  five, 
six  or  eight  (rarely  seven),  long  and  thin,  hearing  the  post-radial  series  of  brachials 
on  a  narrow  facet,  which  occupies  only  a  small  portion  of  their  distal  edge.  Arms 
long,  undivided  or  branching  one  or  more  times ;  the  first  branching  usually  on  the 


238 


ECHINODEEMATA— PELMATOZOA 


PHYLUM  IV 


Fig.  341. 
PlicatocHmis  hexagonus   Müust. 


first  brachial,  never  on  the  second.  If  the  arms  are  undivided  the  pinnules  are 
usually  excessivehj  long  and  reach  to  the  arm  Ups ;  hut  the  length  of  the  pinnules 
decreases  in  proportion  to  the  number  of  arm  divisions  ;  pinnulars  sometimes  tending 
to  fuse  into  a  solid  piece.  Column  as  in  the  Apiocrinidae,  but  never  with  a  proximal 
enlargement. 

Plicatocrinus  von  Münster  (Fig.  341).  Eadials  comparatively  thin,  their 
articular  facets  crescent-shaped ;  the  outer  faces  longitudinally  folded  into 
a  median  ridge.  Arms  ten,  dividing  on  the  first  brachial ;  composed  of 
wedge-shaped  ossicles  united  by  perforate  muscular  articulation.  Pinnules 
composed  of  a  single  piece,  except  the  proximal  ones,  which  consist  of  three 
pieces ;  they  are  angular  or  keel-shaped  along   the  dorsal  side,  and  deeply 

furrowed  on  the  ventral.  Teg- 
men  unknown.  Upper  Jura;  a 
rare  form,  found  in  the  Fran- 
conian  and  Swabian  Alb. 

Hijocrinus   Wyv.    Thomson 

(Fig.  342).     Three  basals  ;  five 

Upper  arms,  bearing   extremely  long 

Jura ;  Streitberg,  Franconia.    a,  Calyx  with  ■niTinnlp«!    wViipVi     rpnpVi     fn     fliP 

radials  and  undivided  base  ;  h,  c,  Dorsal  and  PUmUieS    wnicn    reacn     tO     tne 

lateral  aspects  of  same  (slightly  enlarged) ;  arm    tips  ;    brachials    unitcd    in 
d-f,  First  brachial,  seen  from  the  inside,  out-  .    -,  -  ,  ■,  ^n 

side,  and  from  below  respectively.  Syzygial  grOUpS  Ol  three.       i  eg- 

men  composed  of  five  large 
orals,  surrounded  by  heavily 
plated  perisome.  Recent ; 
Antarctic  Seas. 

Gephyrocrinus  Koehler  and 
Bather.  Similar  to  Hyocrinus, 
but  brachials  united  in  syzy- 
gial groups  of  two;  proximal 
portion  of  column  pentagonal. 
Recent ;  Canaries  and  Madeira. 

Thalassocrinus  A.  H.  Clark. 
Similar    to    Gephyrocrinus,   but 

Hyocrinus    Ijethellianus   Wyv.    Thomson.      Recent;    Atlantic  prOXimal     portiou      of  Column 

Ocean.     A,  Individual  twice  the  natural  size.     B,  Tegmen  several  hexagOnal.         Rcceut  "  Philip- 

tiraes  enlarged ;  am,  Ambulacral  furrows  of  the  arms ;  c.  Dorsal  .        "           *                           •'  " 

canals  ;  an,  Anus  ;  m,  Mouth  ;  o,  Orals  (after  Wyville  Thomson) ;  pines. 

s,Coveringplatesof  ambulacral  grooves.  PtilocrinUS      A.      H.  Clark. 

Five  arms,  unbranched ;  each  brachial,  except  the  most  proximal,  bears  a 
pinnule ;  syzygies  very  infrequent ;  pinnules  not  especially  long.  Recent ; 
Antarctic  Seas  and  west  coast  of  America  to  British  Columbia. 

Calamocrinus  A.  Ag.  Five  brachials ;  the  arms  brauch  several  times. 
Recent ;  Galapagos  Islands  and  Central  America. 


Fig.  342. 


Family  6.     Saccocomidae  d'Orbigny. 

Calyx  small,  hemispherical,  non-pedunculate,  composed  almost  exclusively  of 
five  radials,  which  are  very  thin,  elevated  into  prominent  ridges  along  the  median 
line,  and  enclose  an  extremely  small  basal  plate.  Arms  5x2,  slender,  widely 
separated,  and  giving  off  alternately  towards  the  extremities  simple  incurving 
l)ranches.     Arm-plates  cylindrical ;  each  side  of  the  ambulacral  furrow  lined  with 


CLASS  III 


CRINOIDEA 


239 


wing-like   or    spiniform  projeäions.     TU  entire   skeleton   exhibiting   a   reticulated 
struäure  with  coarse  meshes.     Upper  Jura. 


I 


The  only  known  genus,  Saccocoma  Ag.   (Fig.    343),  occurs  profusely   in 
;he    Lithographie    Stone    of   Eichstädt   and    Solenhofen,    Bavaria.     It   is    a 


Saccocoma  jxxtiTuita  Goldf.  Upper  Jura  (Kimmeridgian) ;  Eichstadt,  Bavaria.  a,  Individual,  natural  size  ; 
h,  Side  View  of  calyx  ;  c,  Calyx  seen  from  below,  -/x ;  d,  Two  of  the  lower  arm-plates  ;  e,  Two  arm-plates  of  a 
higher  order  with  one  of  the  branches  ;  /,  The  upper  part  of  one  of  the  arins  straightened  out ;  g,  Lower 
brachials  of  5.  tenella  Goldf.    (Figs.  d  and  g  greatly,  the  others  slightly  enlarged.) 

free-swimming  form,  whose  affinities  with  the  monocyclic  Plicatocrinidae  were 
first  clearly  demonstrated  by  Jaekel  in  1892. 


Family  7.     Eugreniacrinidae  Zittel. 

(Coadunata  Miller ;  Holopocrinidae  p.p.  Jaekel.) 

Calyx  composed  of  five  (rarely  three,  orfour)  thick,  rigidly  united  radicdsy  resting 
upon  a  proximale  composed  of  fused  basals  and  top  stem-joint ;  basals  inrnsiblCj 
tegmen  unknown.  Costals  compressed,  flange-like ;  united  by  syzygial  sutwes,  or 
fused  with  one  anofher.  Arms  robust,  and  incurving,  usually  branching  on  the 
second  brachial.  Stern  short,  destitute  of  cirri,  and  composed  of  but  a  few  long 
cylindrical  joints  with  granulated  oi'  striated  articular  faces  ;  terminating  in  a  mm'e 
or  less  lobed,  encrusting  root.     Lias  to  Lower  Cretaceous ;  Europe. 

Eugeniacrinus  Miller  (Symphytocrinus  König ;  Caryophyllites  of  pre-Linnaean 


240 


ECHINODERMATA— PELMATOZOA 


PHYLUM  IV 


authors)  (Figs.  344,  345).  Dorsal  cup  small,  saucer  -  shaped,  and  with 
shallow  body-cavity.  Proximale  covered  with  five  radiating  ridges.  B 
invisible  when  the  proximale  is  attached,  but  from  the  course  of  the  axial 
canals  (Fig.  344)  it  is  apparent  that  tbey  are  pushed  upward  so  as  to  be 
completely  enveloped  by  the  R.  The  latter  are  very  heavy,  closely  united, 
and  sometimes  completely  anchylosed.  The  lateral  margins  of  their  upper 
faces  are  extended  upwards  so  as  to  form  conspicuous  projections ;  the  inter- 
mediate  Spaces  are  occupied  by  transverse  ridges  and  deep  fossae.  Costals 
two,  the  Upper  one  axillary.  Structure  of  arms 
unknown.  Abundant  in  the  Upper  Jura,  notably 
in  the  Spongitenkalk  of  Southern  Germany, 
Switzerland,  France  and  the  Carpathians.  Less 
common  in  the  Dogger  and  Lower  Cretaceous  of 
the  Alps. 

Tetracrinus  Münst.  R  typically  four,  rarely 
three  or  five ;  apparently  reposing  directly  upon 
the  column,  as  nx)  B  or  IB  are  visible.  Upper 
face  of  the  proximale  marked  by  four  (sometimes 
three  or  five)  prominent  ridges  which  are  radially 


Fio.  344, 

Eugenioicrinus  caryophyllatios  Miller.  Upper  Jura  ; 
Streitberg,  Franconia.  a,  Calyx  with  centrodorsal, 
Seen  from  one  side  (nat.  size) ;  h,  c,  Ventral  and  dorsal 
aspects,  3/2 ;  d,  d*,  First  brachial,  inner  and  upper 
surface  ;  e,  Second  brachial,  seen  from  the  inside  (nat. 
size).  f-h,  E.  nutans  Goldf.  Same  locality  ;  /,  /*,  First 
and  second  Br  fused  together,  seen  from  the  outside 
and  inside,  respectively  ;  g,  Arm-plate,  figured  in  four 
positions  ;  h,  Dorsal  and  lateral  aspects  of  an  inrolled 
arm. 


Fig.  345. 

Eugeniacrinus  caryojihyllatus 
Miller.  Upper  Jura,  a,  Restora- 
tion,  without  the  arms  (after 
Fraas) ;  h,  Calyx  broken  open  to 
show  the  siliciüed  axial  canals 
(after  Jaekel). 


disposed ;  lower  face  bearing  radiating  peripheral  Striae,  which  are  not  con- 
tinued  over  the  median  portion  of  the  plate.  R  with  transverse  ridges  and 
large  muscular  fossae.     Stem-joints  barrel-shaped.     Upper  Jura  ;  Europe. 

Gammarocrinus  Quenst.  (Sclerocrinus  Jaekel).  Dorsal  cup  massive,  concave 
below.     Upper  Jurassic  ;  Europe. 

Gymnocrinus  Loriol.  First  axillary  remarkably  developed.  Upper  Jura  ; 
Europe. 

Phyllocrinus  d'Orb.  Dorsal  cup  globose ;  R  with  narrow  articular  facets, 
at  either  side  of  which  are  long,  upright  projections.  Upper  Jura  and  Lower 
Cretaceous,  notably  in  the  Mediterranean  district. 

Torynocrinus  Seeley  (Cyrtocrinus  Jaekel;   (?)  Hemicrinus  d'Orb.).     Dorsal 


CLÄSS  III  CRINOIDEA  241 

cup  and  proximale  fused ;  ventral  surface  bent  to  one  side.  Upper  Jura  and 
Lower  Cretaceous ;  Europe. 

Trigonocrinus  Bather.  Oxfordian ;  Europe.  Tormocrinus  Jaekel.  Small 
radial  facets,  rounded  interradial  spines,  and  deep  cup  cavity ;  the  former  has 
less  than  five  rays.     Eocene  ;  Europe. 

Eudesicrinus  Loriol.  Stem  reduced  to  two  short,  thick  segments  which  bear 
the  five  R  directly.    Arms  stout,  branching  on  the  first  brachial.    Lias  ;  Europe. 

Family  8.     Holopidae  Zittel. 

Base  monocyclic  ;  stemless.  Dorsal  cup  beaker-shaped,  and  formed  of  five  fused 
radials,  hy  which  the  hody  was  either  directly  attached,  or  more  frequently  it  was 
supported  hy  a  solid  mass  represeniing  fused,  ^  ^ 

overgrown  or  absorbed  basals.  Tegmen  com- 
posed  of  five  large  triangulär  orals  sur- 
rounded  by  a  narrow  band  of  perisome. 
Arms  five  x  two,  unbranched,  pinnulate, 
strongly  incurving,  and  composed  of  large 
thick  plates.  pj^  g^^. 

Of  the  forms  belonging  to  this  family         a,  h,  Cotyhderma  docens  Deslongch.    Upper  Lias  ; 

Colylederma    Quenst.    (Cotylecrinus    Des-  & 'i1,™^rv;''.!''''rSX"S? '  tS"?; 

long.)  (Fig.  346)  is  found  in  the  Lias:  Asselfingen ;  Baden,  c,  Centrodorsal ;  </,  Circlet  of 
n     Ai  •  !•  Ol,  /-»*-•  .  fused  basals.     (All  figures  of  the  natural  size). 

tyathidium     Steenstrup     (Mtcropocnnus 

Michelin),  in  the  Cretaceous  and  Tertiary ;  and  Holopus  d'Orb.  occurs  both  in 
the  Tertiary  of  Italy,  and  Recent  in  the  Caribbean  Sea,  where  it  inhabits 
shallow  water. 

Range  and  Distribution  of  the  Crinoidea. 

The  discoveries  of  recent  years  have  brought  to  light  an  unexpected 
profusion  of  crinoidal  life  in  the  present  seas,  showing  that  instead  of  being 
a  decadent  and  expiring  race,  as  hitherto  supposed,  the  Crinoids  still  con- 
stitute  a  vigorous  stock  of  cosmopolitan  distribution.  They  are  represented 
by  about  650  species,  falling  into  100  genera,  which  are  distributed  among 
twenty  families  and  nine  additional  subfamilies ;  about  580  of  these  species, 
included  in  eighty-five  genera  and  in  fourteen  families  and  nine  subfamilies, 
are  unstalked  forms  or  Comatulids,  the  dominant  type  of  the  present  fauna, 
while  about  seventy  species,  included  in  fifteen  genera  and  six  families,  are 
stalked  forms. 

The  stalked  Crinoids  attained  their  maximum  development  during  the 
Paleozoic  era.  Three  of  the  principal  Orders — the  Camerata,  Flexibilia  and 
Inadunata — are,  with  the  exception  of  the  genus  Encrinus,  wholly  confined  to 
the  Paleozoic  rocks,  although  the  characteristics  of  the  two  last-named  Orders 
have  continued  in  more  or  less  modified  forms.  The  Articulata,  on  the  other 
band,  appear  first  in  the  Trias,  and  are  represented  continuously  to  the 
present  time. 

Crinoids,  as  a  rule,  have  but  a  very  local  distribution,  but  occasional 
species  are  common  to  two  continents  ;  in  certain  formations  detached  stem- 
joints  and  calyx  plates  occur  so  profusely  as  to  become  of  considerable  rock- 
building  importance,  and  strata  aggregating  many  feet  in  thickness  are  fre- 
quently met  with  which  are  almost  whoUy  constituted  of  Crinoid  remains. 
VOL.  I  R 


242  ECHINODERMATA— PELMATOZOA  phylüm  iv 

While  the  great  majority  of  Recent  stalked  forms  are  deep-sea  inhabitants, 
the  Paleozoic,  on  the  contrary,  often  characterise  shallow  water  deposits,  and 
are  especially  numerous  in  the  vicinity  of  fossil  coral  reefs.  Of  the  Mesozoic 
Crinoids,  the  Eugeniacrinidae  and  Plicatocrinidae,  whose  remains  are  commonly 
associated  with  those  of  Hexactinellid  and  Lithistid  Sponges,  probably  lived 
at  considerable  depths ;  while,  on  the  other  hand,  the  Encrininae,  Apiocri- 
nidae,  Saccocomidae  and  Holopidae,  were  undoubtedly  shallow  water  forms. 

Crinoidal  fragments  have  been  detected  in  the  Cambrian,  but  consist  of 
stem-joints  only.  The  Ordovician  of  England  also  yields  a  variety  of  stem- 
joints,  and  well-preserved  calices  of  Hyhocrinus  and  Baerocrinus  occur  in  rocks 
of  the  same  age  in  the  vicinity  of  St.  Petersburg.  In  North  America,  the 
Trenton  and  Hudson  River  limestones  are  locally  very  rieh  in  Crinoid 
remains.  The  Silurian  localities  of  Dudley,  England,  and  especially  the 
island  of  Gotland,  Sweden,  are  famous  for  the  surprising  abundance  and 
exquisite  state  of  preservation  of  their  fossil  Crinoids.  The  Swedish 
forms  alone  comprise  forty-three  genera  and  176  species.  The  Silurian 
of  North  America,  notably  the  Niagara  Group,  likewise  contains  a  large 
variety  of  forms,  many  genera  being  identical  with  those  of  England  and 
Gotland. 

The  best-known  Devonian  localities  are  the  Eifel,  Rhineland  ;  Nassau, 
Westphalia ;  the  Ardennes  and  Department  of  Mayenne,  France  ;  the  Asturias, 
Spain ;  and  New  York,  Michigan,  and  the  region  about  the  Falls  of  the 
Ohio  River,  in  North  America.  The  Lower  Carboniferous  Limestone  of  Tournay 
and  Vis6,  Belgium,  and  that  of  England,  Ireland,  and  the  vicinity  of  Moscow, 
Russia,  are  occasionally  charged  with  exceptionally  well-preserved  crinoidal 
remains.  But  the  most  famous  of  all  horizons  is  the  Lower  Carboniferous 
Limestone  of  North  America,  where  in  particular  the  localities  of  Burlington, 
Iowa,  and  Crawfordsville,  Indiana,  have  acquired  a  world-wide  celebrity. 

The  Upper  Carboniferous  contains  large  areas  of  crinoidal  limestone,  but 
well-preserved  specimens  occur  rarely,  the  most  notable  being  at  Kansas  City, 
Missouri ;  some  interesting  forms  f rom  that  horizon  are  found  in  Australia. 
The  Permian  has  yielded  but  a  few  genera,  and  those,  so  far  as  yet  known, 
belong  to  the  Inadunata.  A  remarkable  Crinoid  fauna  of  this  age  has  also 
been  discovered  in  the  Island  of  Timor. 

^From  the  Trias  only  the  Encrininae  and  a  few  species  of  Pentacrinus  are 
as  yet  known.  The  remaining  members  of  the  Articulata  make  their  appear- 
ance  in  the  Jura  and  Cretaceous,  and  with  the  exception  of  the  Eugenia- 
crinidae and  the  Saccocomidae,  the  families  are  still  represented  in  the  existing 
fauna. 

[The  text  for  the  entire  subphylum  Pelmatozoa  has  been  revised  by  Mr.  Frank  Springer 
of  East  Las  Vegas,  New  Mexico,  and  "Washington,  D.C.  The  treatment  of  the  classes  Cystoidea 
and  Blastoidea  is  substantially  the  same  as  in  the  former  edition  of  this  work,  but  that  of  tlie 
Crinoidea  reflects  the  great  progress  in  our  knowledge  of  this  group  tliat  has  been  made 
during  the  past  decade.  In  that  part  of  the  revision  which  deals  with  post- Paleozoic  Crinoids 
Mr.  Springer  and  Mr.  Austin  Hobart  Clark,  of  the  United  States  National  Museum  at 
Washington,  have  co-operated  with  a  view  toward  making  the  new  knowledge  of  later  and 
Recent  Crinoids  more  generally  available  for  paleontologists.  Lack  of  space  alone  prevented 
a  more  detailed  discussion  of  Recent  Comatulids,  such  as  had  been  actually  prepared 
for  the  present  work  by  Mr.  Clark.  The  student  is  therefore  referred  to  the  independent 
publications  of  these  two  well-known  echinodermologists. — Editoh.] 


CLASs  III  CRINOIDEA 

Table  showing  the  Vertical  Range  of  the  Crinoidea. 


243 


Families. 

1 

o 

'S 
o 

03 

m 

1 

'S 

1 

1 

1 

1 

•-3 

« 

Tertiary. 
Recent. 

I.  Camerata 

1.  Cleiocrinidae 

2.  Reteocrinidae 

3.  Dimerocrinidae 

4.  Rhodocrinidae 

5.  Melocrinidae 

6.  Calyptocrinidae 

7.  Batocrinidae 

8.  Actinocrinidae 

9.  Platycrinidae 

10.  Hexacrinidae 

11.  Acrocrinidae 

II.  Flexibilia 

1.  Lecanocrinidae 

2.  Sagenocrinidae 

3.  Iclithyocrinidae 

4.  Taxocrinidae 

III.  Inadun  ATA 
1.  Larviformia 

1.  Stephanocrinidae 

2.  Pisocrinidae 

3.  Haplocrinidae 

4.  Allagecrinidae 

5.  Synbathocrinidae 

6.  Cupressocrinidae 
2.  Fistulata 

1.  Hybocrinidae 

2.  Heterocrinidae 

3.  Anomalocrinidae 

4.  Cremacrinidae 

5.  Catillocrinidae 

6.  Belemnocrinidae 

7.  Dendrocrinidae 

8.  Crotalocrinidae 

9.  Cyatliocrinidae 

10.  Botryocrinidae 

11.  Poteriocrinidae 

IV.  Articulata 

lo  Bourgueticrinidae 

2.  Phrynocrinidae 

3.  Apiocrinidae 

4.  Pentacrinidae 
(a)  Pentacrinids 

(&)  Thiolliericrinids 
(c)  Coraatulids  ^ 

5.  Plicatocrinidae 

6.  Saccocomidae 

7.  Eugeniacrinidae 
1         8.  Holopidae 



1 

1 

—• 

i 

i 

j 

1 



.._ 



' 

":i 

1 



i 

i 

— 







— • 

1 

j 

— 

1 

i 



— 

»... 



........ 

i 
•          1 

- 

:      ! 





! 

« 

! 





—  .. 

? 

1 

' 1. 









i 



; 

i 

— 

1 

! 

\ 

1 1 

i 

1 

!  



i 

1 

1 





ji 

1                                      ' 

1 

! 

_^.^ 

1 

L.^ 

j 

-! 

Includini'  Mt(rs)i 


i';,ih 


244  ECHINODERMATA— ASTEROZOA  phylum  iv 

SuBPHYLUM  B.     Asterozoa  Leuckart.^ 

Stemless  Echinoderms  with  depressed,  pentagonal  or  star-shaped  body,  consisting 
of  a  central  disk  and  five  or  more  rays  {or  "  arms  ").  Mouth  inferior  and  central  in 
Position.  Ambulacral  tube-feet  restricted  to  the  under  surfaxe  of  the  rays.  Internal 
skeletal  pieces  of  the  ambulacra  articulated  together  like  vertebrae,  or  apposed  like  the 
rafters  of  a  pent-house.  Integument  coriaceous,  strengthened  by  small,  irregulär, 
loosely  or  firmly  united  calcareous  plates,  some  of  which  bear  spines,  protuberances  or 
papillae,  the  whole  constituting  a  covering  showing  the  greatest  diversity  in  details. 

The  Asterozoa  comprise  the  two  classes  of  Asteroidea  (Starfish) ;  and 
Ophiuroidea  (Brittle  Stars  and  Basket-fish).  In  both  types  the  body  consists 
of  a  central  disk  containing  the  principal  viscera,  and  giving  ofF  five  or  more 
radiating  processes  or  arms.  The  radiating  ambulacral  vessels  are  protected 
by  an  internal  skeleton  consisting  of  a  double  row  of  calcareous  bodies  {ambul- 
acral ossicles),  the  components  of  each  pair  being  separated  and  movable  to  a 
slight  extent  in  the  Asteroidea,  but  being  welded  together  so  as  to  form  a 
series  of  disks  in  the  Ophiuroidea.  The  ambulacral  grooves  are  open  in  the 
Asteroidea ;  but  in  the  Ophiuroidea  they  are  covered  by  dermal  plates,  and 
the  tube-feet  project  at  the  sides  of  the  arms.  The  integumentary  skeleton 
sometimes  appears  leathery  on  the  dorsal  surface,  but  is  generally  strengthened 
by  calcareous  plates  or  ossicles  some  of  which  usually  bear  spines  or  tubercles. 

Asterozoans  are  known  as  early  as  the  Cambrian  era,  and  haVe  a  continuous 
history  onward  to  the  present  time.  They  are  of  rather  rare  occurrence  as  f ossils, 
and  are  f ound  chiefly  in  slaty,  calcareous,  or  arenaceous  strata  which  have  been 
deposited  in  shallow  water.  The  Asterozoans  are  the  most  homogeneous  and 
most  persistent  type  of  all  the  Echinodermata.  Both  the  Asteroidea  and 
Ophiuroidea  are  represented  in  the  Ordovician  and  Silurian  by  well-difFerentiated 
forms  which  do  not  difFer  materially  from  those  now  living.  The  only  notice- 
able  difFerence  is  that  many  of  the  Paleozoic  Asterozoans  exhibit  an  alternate 
arrangement  of  the  ambulacral  ossicles,  while  in  all  Recent  species  these  are  in 
a  double  row,  with  the  ends  directly  apposed. 

Whether   this  more   or   less  disjunct  and   alternating  condition   of    the 

vertebral  ossicles   in  Paleozoic   Asterozoa    is    really   a  primitive   feature   of 

fundamental  importance  must  still  be  considered  an  open  question.     It   is 

quite  possible  that  the  apparent  alternation  in  Paleozoic  starfishes  is  due 

to  conditions  of  preservation,  or  if  not,  is  an  inconstant  and  insignificant 

1  Literature  :  Müller,  J.,  and  Troschel,  F.  H.,  System  der  Asteriden.  Brunswick,  1842. — 
Forhes,  E.,  Monograph  of  the  Echinodermata  of  the  British  Tertiaries.  Palaeont.  Soc,  1852. — 
Bülings,  K,  Figures  and  Descriptions  of  Canadian  Organic  Eemains.  Geol.  Survey  Canada,  Decade 
iii.,  1858. —  Wright,  T.,  Monograph  on  the  British  Fossil  Echinodermata  of  the  Oolitic  Formations, 
vol.  ii.,  Asteroidea  and  Ophiuroidea.  Palaeont.  Soc,  1863-80. — Hall,  J.,  Twentieth  Keport  on  the 
New  York  State  Cabinet,  1868. — Quenstedt,  F.  A.,  Petrefactenkunde  Deutschlands,  vol.  iv.,.1874- 
1876. — Ludwig,  H.,  Morphologische  Studien  an  Echinodermeu.  Leipzic,  1877-79. — Neumayr,  M., 
Morphologische  Studien  über  fossile  Echinodermeu.  Sitzungsber.  Akad.  Wiss.  Wien,  vol.  Ixxxiv. 
1881. — Carpenter,  P.  H.,  Minute  Anatomy  of  the  Brachiate  Echinodermata.  Quart.  Journ.  Micro- 
scop.  Sei.,  1881. — Stürtz,  B.,  Beiträge  zur  Kenntniss  paläozoischer  Seesterne.  Palaeontographica, 
vols.  xxxii.  and  xxxvi.,  1886,  1890. — Idem,  über  versteinerte  imd  lebende  Seesterne.  Verhandl. 
d.  naturhist.  Vereins  Eheinlande,  Westphalen,  etc.,  5th  ser.  vol.  x.,  1892. — Sladen,  W.  P.,  and 
Spencer,  W.  K.,  Monograph  on  British  Fossil  Echinodermata  from  the  Cretaceous  Formations,  vol.  ii. 
Asteroidea  and  Ophiuroidea.  Palaeontogr.  Soc,  1891-1908. — Gregory,  J.  W.,  The  Stelleroidea,  in 
Lankester's  Treatise  on  Zoology,  Part  iii.,  1900. — Jaekel,  0.,  Asteriden  und  Ophiuriden  aus  dem 
Silur  Böhmens.  Zeitschr,  Deutsch.  Geol.  Ges.,  1903,  vol.  \v.— Bather,  F.  A.,  Guide  to  Fossil  In- 
vertebrates,  etc.  British  Mus.  Publ.,  1907. — Schöndorf,  F.,  Über  einige  Ophiuriden  und  Asteriden 
des  englischen  Silur,  etc.     Jahrb.  Nassauischen  Ver.  Naturk.,  Jhrg.  63,  1910. 


CLASS  I  ASTEROIDEA  245 

character,  as  Gregory  has  claimed.  In  Ophiurans,  however,  it  is  almost 
certain  that  alternation  is  a  primitive  and  very  important  character.  The 
ventral  position  of  the  madreporite  in  Paleozoic  Starüshes  and  the  absence  of 
mouth  shields  in  Paleozoic  Ophiuroids  point  to  an  intimate  relationship 
between  the  two  groups ;  and  this  inference  is  still  further  confirmed  by  our 
knowledge  of  several  recent  and  fossil  intermediate  forms  {Astrophiura^  Pro- 
taster ^  Ophiamhix,  etc.). 

If  one  places  a  Starfish  or  Brittle  Star  with  the  mouth  uppermost,  it  will 
be  Seen  that  the  actinal  side  corresponds  with  the  tegmen,  and  the  central 
disk  with  the  base  of  a  Pelmatozoan.  When  oriented  in  this  manner,  the 
Position  of  the  principal  organs  (ambulacral,  circulatory  and  nervous  Systems)  is 
the  same  in  both  groups.  The  homology  between  the  arms  of  an  Asterozoan 
and  those  of  a  Crinoid  or  Cystid,  or  the  ambulacral  fields  of  a  Blastoid,  can 
also  hardly  be  doubted.  But  efForts  to  interpret  a  homology  between  plates 
of  the  dermal  skeleton  as  developed  in  either  group  have  been  only  partially 
successful ;  the  reason  being  that  these  structures  becanie  variously  modified 
and  specialised  throughout  the  difFerent  classes  at  an  extremely  early  period. 

A  comparison  of  the  ontogenetic  stages  passed  through  by  the  Pelmatozoa 
and  Asterozoa,  so  far  as  at  present  known,  reveals  nothing  definite  in  regard 
to  their  close  relationship.  The  Asterozoans  are  most  nearly  comparable 
with  certain  of  the  Cystideans  (Agelacrinus  and  th«  Callocystidae).  But  that 
they  are  the  direct  descendants  of  the  Cystoidea  appears  very  improbable,  for 
both  geological  and  morphological  reasons.  The«fact  is,  that  both  types 
appear  simultaneously  and  in  a  high  State  of  development,  each  being  quite 
distinct  from  the  other,  as  far  back  as  the  Cambrian. 

While  it  is  clear  that  a  well-marked  Separation  exists  between  the  two 
classes  of  Asteroidea  and  Ophiuroidea,  there  is  very  unsatisfactory  evidence 
in  Support  of  a  third  group  of  equal  rank,  such  as  Ophiocistia  Sollas  or  Aulu- 
roidea  Schöndorf.  The  genera  composing  the  former  may  better  be  retained 
among  the  Ophiurans,  while  as  for  the  latter,  it  is  difficult  to  believe  that 
the  characters  assigned  to  it  are  real.  More  likely  these  supposed  characters 
rest  upon  a  misinterpretation  of  the  material.  Fossil  Asterozoans  seem  to 
have  been  preserved  in  many  cases  only  after  the  decay  or  removal  of  much 
or  all  of  the  non-calcareous  parts.  Sometimes  apparently  the  entire  abactinal 
side  has  been  destroyed.  In  other  cases  only  impressions  remain,  chiefly 
of  the  harder  parts,  and  the  actual  structure  cannot  be  ascertained.  It 
is  not  surprising,  therefore,  that  our  knowledge  of  the  Paleozoic  forms 
is  still  incomplete,  and  that  erroneous  interpretations  should  have  been  placed 
upon  some  of  their  structural  characters. 

Olass  1.    ASTEROIDEA  Burmeister.    Starfishes.i 

Asterozoans  whose  simple  and  more  or  less  flattened  arms  are  prolongations  of 
the  central  disJc,  and  contain  the  hepatic  appendages  of  the  alimentary  canal,  as  well 

1  Literature  :  Forbes,  K,  British  Fossil  Asteriadae.  Mem.  Geol.  Survey,  vol.  ii.,  Part  ü-,  and 
Decade  iii.,  1848  and  1S50.— Salter,  J.  W.,  New  Palaeozoic  Star-Fishes.  Ann.  Mag.  Nat.  Hist  ,  1857, 
vol.  XX.— (ymy,  J.  K,  Synopsis  of  the  Species  of  Star- Fish  in  the  British  Miiseuni,  \%Q^—Sivmio- 
loitsch,  S.,  Ueber  einige  Asteroiden  der  rheinischen  Grauwacke.  Sitzunpsber.  Wien.  Akad.,  1871, 
vol.  Ixiil-Sars,  O.  0.,  Researches  on  the  Structure,  etc.,  of  the  genus  Brisinga.  Chnstiana,  18/5.— 
Perrier,  E.,  Revision  de  la  collection  des  Stellerides  du  Museum  d  Hist.  Nat.  de  Paris.  Arch.  de 
zool.  experim.,  iv.,  v.,  -[ S7 5-7 6.— Agassiz,  A.    North  American  Star-Fishes.     Memoirs  Museum 


246  ECHINODERMATA— ASTEROZOA  phylum  iv 

as  the  generative  organs.  Ämhulacrol  feet  disposed  in  rows  along  deep  open  grooves 
on  the  under  or  actinal  surface  of  the  arms. 

Starfishes  have  typically  five  arms  (but  in  some  cases  as  many  as  eight, 
teil,  twenty,  forty,  or  more),  which  are  prolongations  of  the  central  disk, 
usually  not  sharply  marked  off  from  the  same.  The  integumentary  skeleton 
consists  of  plates  which  are  either  contiguous  with  one  another  along  their 
edges,  overlapping  or  united  in  a  reticulate  fashion,  and  covered  with  a  leathery 
skin.  The  calcareous  plates  often  bear  movable  spines,  or  they  may  be 
tuberculated  or  granulated.  Modified  spines  with  a  special  function  and 
called  pedicellariae  are  found  in  most  Asteroidea  and  are  often  conspicuous. 
They  never  occur  in  Ophiurans  or  Holothurians,  and  are  not  known  among 
Pelmatozoa,  but  what  appear  to  be  homologous  organs  occur  in  nearly 
all  Echini.  The  abactinal  surface  usually  exhibits  a  central  or  sub- 
central anus,  and  also  a  madreporite,  which  is  situated  in  one  (rarely  two 
or  more)  of  the  interradii.  The  madreporite  is  covered  with  labyrinthic 
furrows,  and  is  perforated  for  the  admission  of  water  into  the  so-called  ston^ 
canal,  whence  it  is  conveyed  into  the  water-vascular  ring  surrounding  the 
mouth.  The  protrusive  caecal  processes  (papulae),  which  in  the  more 
primitive  forms  are  restricted  to  the  dorsal  surface,  but  in  the  more  specialised 
are  distributed  over  the  whole  body,  serve  as  respiratory  organs,  the  body 
fluids  being  brought  into  close  contact  with  the  oxygenated  water. 

The  mouth  occupies  the  centre  of  the  ventral  surface,  and  is  pentagonal  in 
contour,  owing  to  the  projection  of  five  pairs  of  interradially  disposed  oral 

plates.     Each  of  the  arms  is  traversed  on 

^        ^  /k    A  the  under  or  oral  side  by  a  broad  and  deep 

»^^  J|j_.W  furrow,  which  tapers    gradually  in  passing 

^^0  TO    tii)         from  the  mouth  to  the  tip  of  the  arm,  where 

Fig.  348.  it  is  termiuatcd  by  a  simple  grooved  plate 

oJar'pils  „f    \^rTSä^i,rAt(^JS-  im  l<^i}^ät}^oeular  plate.     The  roof 
Pentago7Mster(^)  irom     tagonaster  (?)  from  of  each  ambulacral  furrow  IS  formed  bv  two 

the   Upper    Jura   of       the  Upper    Jura    of  jr         r^        ti  ^i  i  j.  z 

Streitberg.   2/^.  Streitberg.   i/j.         rows  Ol    raiter-like,  rather  elongate,  ambu- 

lacral ossicles,  the  inner  ends  of  which  are 
held  together  by  muscles  (Figs.  348-350).  Eunning  along  the  centre  of  the 
groove  on  its  ventral  side  are  placed  in  succession  the  radial  water -tube, 
blood-vessel  and  nerve  cord.  These  are  all  homologous  with  the  like-named 
organs  of  Ophiuroids. 

The  form  of  the  ambulacral  ossicles  difFers  in  diiferent  genera.  In  all 
Recent  forms  the  ends  are  directly  apposed  against  one  another  in  the  median 
line  of  the  ambulacral  grooves ;  but  in  Paleozoic  forms  they  were  apparently 
arranged  in  alternate  rows,  and  inclined  towards  one  another  at  a  very  small 
angle.     Each  pair  of  ambulacral  plates  is  excavated  at  the  sides,  so  as  to  give 

Comp.  Zoölogy,  Cambridge,  v.,  1877.— Viguier,  C,  Anatomie  comparee  du  squelette  des  Stellerides. 
Arch.  de  zool.  experim.,  vii.,  1878.— Sladen,  W.  P.,  Eeport  on  the  Asteroidea.  Scient.  Kesults, 
Challenger  Expedition,  1889,  vol.  xxx.—Fraas,  E.,  Die  Asterien  des  weissen  Jura.  Palaeonto- 
graphica,  1886,  vol.  xxxii.— Gregory,  J.  W.,  On  Lindstroemaster  and  the  Classification  of  the 
Palaeasterids.  Geol.  Mag.,  1899,  dec.  4,  vol.  vi.—Linstow,  0.  v .,  Zwei  Asteroiden  aus  mär- 
kischem Septarienton,  etc.  Jahrb.  k.  Preuss.  Landesanst.,  1909,  vol.  xxx.  pt.  2.— Schöndorf,  F., 
Die  Organisation  und  systematische  Stellung  der  Sphaeriten.  Arch.  f.  Biontologie,  1906,  vol.  i. 
— Idem,  Paläozoische  Seesterne  Deutschlands.  Palaeontogr.  1909-10,  vols.  Ivi.,  Ivii. — Ide7n,  Die 
fossilen  Seesterne  Nassaus.  Jahrb.  Nassauischen  Ver.  Naturk.,  Jahrg.  62,  1909.— Jludson  G.  ff., 
A  fossil  Starfish  with  ambulacral  covering  plates.     Ottawa  Nat.,  1912,  vol.  xxvi. 


I       rise  bv 


ASTEROIDEA 


247 


rise  by  their  apposition  to  a    series  of  small  apertures,  through  which  the 
distensible  tube  feet  or  pedicels  are  emitted.     The  latter  are  the  downward 


md 


ad^     mir. 


Fig.  349. 


Astropecten  aurantiacus  (Linn.).  Recent; 
Mediterranean.  Enlarged  vertical  section  of 
one  of  the  arms.  am,  Ambulacral  ossicles  ; 
ad,  Adambulacral  i)late  ;  mv,  Infero-marginal 
plate ;  md,  Supero-marginal  plate ;  i,  Super- 
ambulacral  plate. 


aa. 

FiQ.  350. 

Asterias  ruhens  Linnaeus,  Recent ; 
German  Ocean.  Enlarged  vertical 
section  of  one  of  the  arms.  am,  Am- 
bnlacral  ossicles  ;  ad,  Adambulacral 
plates  ;  mv,  Infero  -  marginal  plates  ; 
a,  Radiating  water-tube  ;  b,  Ampullae  ; 
p,  Tube-feet. 


prolongations  of  lateral  branches  given  off  by  the  radial  ambulacral  vessel ; 
the  upward  prolongations  of  the  same  form  small  sacs  called  ampullae,  by 
means  of  which  water  is  forced  into  the  tube  feet. 

The  lower  ends  of  the  ambulacral  ossicles  rest  against  a  series  of 
adambulacral  plates,  and  in  many  forms  these  are  bounded  in  turn  by  large 
marginal  plates  (Fig.  349).  Intermediate  plates  are  those  which  are  inserted 
between  the  infero-marginal  plates  and  the  adambulacral  plates.  By  the 
term  dorsal  plates  are  understood  all  calcareous  bodies  occurring  on  the  dorsal 
side  of  the  body. 

Perfectly  preserved  Starfishes  are  known  only  from  a  few  localities,  such  as 
Bundenbach  in  Rhenish  Prussia,  the  usual  mode  of  occurrence  being  in  the  form 
of  moulds,  or  detached  plates.    The  earliest  forms  are  found  in  Cambrian  rocks. 

There  is  no  generally  accepted  Classification  of  the  Starfishes.  Not  only 
do  specialists  disagree  as  to  the  Orders  and  families,  but  tjiere  is  the  widest 
divergence  of  opinion  as  to  the  principles  upon  which  the  Classification  should 
be  based.  Unfortunately  none  of  the  zoologists  who  have  in  recent  years 
attempted  to  formulate  a  Classification  for  the  group,  except  Sladen,.has  taken 
fossils  into  account,  and  even  Sladen  was  inclined  arbitrarily  to  separate 
Paleozoic  and  Recent  forms.  The  latest  authority,  Fisher,  accepts  three 
Orders  but  does  not  consider  their  limits  as  satisfactorily  determined.  The 
study  of  Recent  forms  has  shown  that  the  characters  of  the  tube-feet, 
reproductive  organs  and  other  soft  parts  are  of  real  importance  in  determin- 
ing  family  limits,  and  that  the  pedicellariae  are  possibly  of  even  ordinal 
importance,  hence  it  is  exceedingly  difficult  to  intercalate  fossil  Starfishes  in  a 
Classification  of  the  living  forms.  As  has  been  suggested  above,  Gregory  is 
very  possibly  correct  in  his  view  that  the  alternation  of  the  ambulacral 
ossicles  cannot  be  considered  of  fundamental  importance,  but  may  often  be 
only  a  result  of  pressure  during  fossilisation.  It  certainly  ought  not  to  be 
used  to  isolate  all  Paleozoic  forms,  or  most  of  them,  in  a  class  by  themselves. 
One  character  upon  which  stress  was  first  laid  by  Sladen  has  come  to  be 
generally  regarded  as  of  fundamental  importance,  i.e.  the  size  and  appearance 
of  the  marginal  plates.  The  genera  in  which  these  plates  are  large  and 
conspicuous  have  the  papulae  confined  to  the  space  bounded  by  the  upper 
series  or  supero-marginals ;  and  this  group,  called  Phanerozonia  by  Sladen,  is 
now  quite  generally  accepted  although  its  exact  limits,  at  least  among  living 


248 


ECHINODERMATA— ASTEROZOA 


PHYLUM  IV 


Starfishes,  are  still  uncertain.  All  other  Starfishes  may  be  grouped,  as  was 
done  by  Sladen,  in  a  contrasting  order,  Cryptozonia ;  but  this  is  probably  not 
a  natural  group,  and  Fisher  distinguishes  two  divisions.  These,  however,  are 
separated  by  characters  not  ascertainable  in  Paleozoic  remains,  and  for  practical 
purposes,  the  paleontologist  may  well  accept  the  Cryptozonia. 


Order  1.     PHANEROZONIA. 

Asteroidea  in  which  the  marginal  plates  are  large  and  conspicuous;  papulae 
nearly  always  confined  to  the  dorsal  surface;  amhulacral  ossicles  not  crowded,  and 
tube  feet  in  two  rows  in  each  amhdacral  groove. 

This  Order  includes  a  large  proportion  of  the  Paleozoic  and  Mesozoic 
Starfishes,  besides  numerous  Eecent  genera.  Fisher  groups  the  Eecent  forms 
in  no  less  than  a  dozen  families,  and  Gregory  gives  four  others  for  Paleozoic 
species  alone.  Many  of  the  Recent  families  are  not  known  as  fossils,  and 
others  may  have  one  or  a  few  extinct  representatives.  The  most  important 
families  and  genera  from  a  paleontological  point  of  view  are  the  following. 


Family  1.     Palaeasteridae. 

The  typical  members  of  this  family  have  the  ambulacral  ossicles  more  or 

less  completely  alternating.     The  adambulacral  plates  are  most  conspicuous 

B  in    the    mouth   parts.     The 

marginal  plates  and  many 
of  the  abactinal  plates  are 
conspicuous. 

The  exact  limits  of  this 
family  are  hard  to  determine, 
as  the  known  forms  are  all 
from  the  lower  Paleozoic. 
The  typical  genus  Palaeaster 
Hall  (Fig.  351)  is  known 
from  both  Europe  and 
America.  Hudson  has  re- 
cently  proposed  a  new  order 
and  family  for  an  interesting 
S  t  a  r  fi  s  h  (Protopalaeaster) 
from  the  Ordovician  rocks  of 
Canada.  It  is,  however, 
probably  allied  to  Palaeaster. 
The  plates  which  Hudson 
calls  epineurals  are  probably 
the  amhdacrals  seen  from  within,  the  dorsal  side  of  the  animal  being  lost. 

Several  genera  allied  to  Palaeaster  have  been  described  (Petraster  Billings ; 
Ärchasterias  Müller ;  Argaster  Hall ;  Ataxaster  Jaekel,  etc.),  while  other  less 
typical  forms  (Xenaster  Simonowitsch ;  Tetraster  Eth.  and  Nich.)  have  been  the 
subject  of  debate  as  to  their  true  position.  Whether  Lindstroemaster  Gregory 
is  properly  referable  to  this  family  is  not  certain ;  it  bears  considerable  super- 
ficial resemblance  to  the  Goniasteridae. 


Fio.  351. 
Palaeaster  eucharis  Hall.     Devonian ;  Hamilton,   New  York.     A 
Ventral  aspect,  natural  size.     B,  Dorsal  surface  of  one  of  the  arnis 
C,  Diagrammatic  view  of  ventral  surface  of  the  arms  (after  Hall). 


CLASS  I 


ASTEROIDEA 


240 


Family  2.     Astropectinidae. 

This  is  one  of  the  largest  families  of  Recent  and  Mesozoic  Phanerozonia, 
about  twenty  Recent  genera  being  known.  The  ambulacral  ossicles  are 
opposite  but  that  seems  to  be  the  only  difference  from  the  Palaeasteridae. 
The  type-genus,  Astropecten  Gray  (Fig.  349),  occurs  in  the  Lias  and  later 
Mesozoic,  and  is  still  a  large  and  widespread  genus.  It  is  quite  possible  that 
some  Paleozoic  forms  are  nearly  related,  if  not  actually  congeneric,  as  for 
example,  Astropecten  schlüteri  Stürtz,  from  the  Devonian.  The  lower  Silurian 
Siluraster  Jaekel  is  also  very  probably  one  of  this  family. 


Family  3.     Aspidosomatidae. 

This  family  is  characterised  by  alternate  ambulacral  ossicles  and  large 
interradial  areas.  The  rays  are  more  or  less  petaloid  or  tapering,  and  the 
disk  is  large.     All  of  the  known  ^  c; 

forms  are  from  the  Paleozoic  and 
their  structure  is  not  only  incom- 
pletely  known,  but  there  is  the 
widest  difference  of  opinion  in  inter- 
preting  such  characters  as  are  dis- 

tinguishable.  The  type  -  genus  ^'<255ig^öifc^tfQJiiMttÖ?SyMBiKI^^  i  b 
Aspidosoma  (Fig.  352)  has  been 
very  carefully  studied  by  Schön- 
dorf. As  a  result  of  these  studies, 
he  proposed  a  new  class  called 
Auluroidea.  The  structure  of 
Aspidosoma  shows,  however,  that 
it  is  probably  a  phanerozonate  Star- 

fish.    Allied  genera  are  Falaeonectria  ^^^^^^^^^  petaloüUs  Simon.     Lower  Devonian;  NieHler- 

and  PalaeOStella   Stürtz,  and  Tricha-  lahnstein,  Nassau.  ^,  Ventral  aspect  natural  size^  Arm 

.  '  viewed  from  the  dorsal  side.     "^   a7„„4.™i *■  ^f  „^r„ 

steropStS  Eck.  enlarged  (after  Simonowitsch). 


C,  Ventral  aspect  of  arm, 


Pentagonaster  (;!) 
impressns  (Quenst.). 
Upper  Jura ;  Reiohen- 
bach  im  Thäle.  A, 
Supero  -  marginal 
plate.  B,  Infero- 
inarginal  plate.  C, 
Plate  with  supposed 
pedicellariae  (after 
Quenstedt). 


Family  4.     Taeniasteridae. 

In  this  family,  which  is  also  confined  to  the  Paleozoic, 
the  disk  is  very  small  and  the  rays  are  long  and  tapering. 
The  adambulacral  plates  are  large  and  marginal  in  position. 
The  marginal  plates  bear  spines  on  their  free  ends.  The 
principal  genera  are  Taeniaster  and  Stenaster  Billings,  from 
the  Lower  Silurian  of  Canada,  and  Saiteraster  Stürtz,  from 
the  Silurian  of  England.  Perhaps  Protasteracanihion  Stürtz, 
from  the  Devonian  of  Germany,  also  belongs  here. 


Family  5.  Goniasteridae  (  =  Pentagonasteridae). 
These  Starfishes  are  generally  recognisable  by  their  flattened 
form,  Short  rays,  very  large  disk,  and  very  conspicuous 
marginal  plates.  The  family  is  a  large  one,  with  more  than 
forty  Eecent  genera,  and  its  limits  are  ill  defined.  It  first  appears  in  the 
Jurassic,  and  it  is  well  represented  in  Cretaceous  strata.    The  genus  Pentagmiaster 


250 


ECHINODERMATA— ASTEROZOA 


PHYLÜM  IV 


Gray,  was  monotypic  when  described,  and  as  now  limited  probably  contains 
no  fossil  forms ;  but  a  considerable  iiumber  of  species  and  frägments  (Figs. 
347,  348,  353)  from  the  Mesozoic  have  been  referred  to  it.     An  allied  genus, 


Fig.  354. 
Lower  Chalk  ;    Sussex.      A,  Ventral  aspect. 


B,  Viewed  from  one  side 


Metofiaster  parkinsoni  (Forbes). 
(after  Forbes). 

Metopaster  Sladen  (Fig.  354),  is  represented  by  numerous  species  in  the 
Cretaceous  rocks  of  England.  Other  Cpetaceous  genera  are  Pycinaster  Spencer, 
and  Mitraster  Sladen,  while  Leptaster  -de  Loriol  is  f ound  in  Jurassic  strata. 


Siihaerites  scutatus  Gold  f. 
Upper  Jura ;  Sontheim, 
Würtemberg. 


A,  Oreastef  Jurassims (Zitt.).  Upper  Jura  ;  Bemfeld,  near  Ingolstadt, 
Bavaria.  ^f^.  B,  0.  thoracifer  (Gein.).  Pläner ;  Plauen,  Saxony. 
Marginal  plate.     C,  0.  primaevus  (Zitt.).     Upper  Jura  ;  Streitberg. 


A,  Sphaerites  tahulatus 
Goldf.  B,  Sphacr.  punctatus 
Goldf.  Upper  Jura;  Streit- 
berg, Franconia. 


Several  Recent  genera,  such  as  Calliderma  Gray ;  Nymphaster  Sladen ; 
Comptonia  Gray,  have  been  thought  to  have  Cretaceous  representatives,  and 
there  is  little  reasori  to  doubt  that  many  Cretaceous  Starfishes  of  this  family 
were  congeneric,  at  least  in  a  broad  sense,  with  those  of  to-day. 


CLASS  I  ASTEROIDE A  251 

I'amily  6.  Oreasteridae  (wrongly  Pentacerotidae). 
This  family  includes  some  of  the  largest  Eecent  Starfishes,  characterised  by 
a  massive  skeleton,  with  large,  though  sometimes  concealed,  marginal  plates. 
Conspicuous  spines  or  tubercles  are  commonly  found  on  the  abactinal  plates. 
The  type  genus  Oreaster  M.  and  T.  (wrongly  Fentaceros)  (Fig.  355),  is  wide- 
spread  in  shallow  water  in  the  tropics,  while  geologically  it  is  known  at  least 
as  early  as  the  Upper  Jura.  Numerous  species  of  this  genus  occur  in  the 
Cretaceous.  Arthraster  Forbes,  and  Stauranderaster  Spencer,  from  the  British 
'^retaceous  probably  belong  to  this  family. 

Family  7.  Sphaerasteridae. 
Isolated  plates,  to  which  Quenstedt  gave  the  name  Sphaerites,  from  the 
Jurassic  rocks  of  Germany,  France  and  Switzerland,  have  long  puzzled 
paleontologists,  but  Schöndorf  has  recently  shown  that  they  belong  to  certain 
remarkable  Starfishes,  which  he  calls  Sphaeraster,  allied  to  the  Oreasteridae. 
In  some  cases  (Fig.  356)  the  plates  bear  large  spines,  but  in  others  they  are 
simply  punctate  (Fig.  357),  or  quite  smooth.  The  animal  was  high  hemi- 
spherical  in  form,  and  the  large  ones  were  25  cm.  in  diameter.  They  seem  to 
have  been  confined  to  Jurassic  seas. 

Order  2.     CRYPTOZONIA. 

Asteroidea  in  which  the  marginal  plates  are  small  and  inconspicuous ;  papulae 
distrihuted  on  the  oral  surface ;  amhulacral  ossicles  are  often  crowded  and  tube-feet 
may  he  infour  rows  in  each  groove. 

Between  fifteen  and  twenty  families  of  cryptozonate  Starfishes  are  now 
recognised,  but  the  great  bulk  of  these  are  Recent  forms.  The  order  is  rare  in 
the  Paleozoic,  and  the  structure  of  those  forms  which  are  referred  to  it  is  im- 
perfectly  known.  Accordingly,  their  systematic  position  is  doubtful.  The 
genus  Palasterina  M'Coy  (Cambrian  to  Devonian ;  Europe  and  North  America) 
is  regarded  by  some  writers  as  cryptozonate  and  by  others  as  phanerozonate. 
It  is  probably  related  to  Asterina  Nardo,  a  widespread  Recent  genus,  which 
Sladen  considered  phanerozonate,  other  writers  to  the  contrary  notwith- 
standing.  The  genera  Palaeocoma,  Bdellacoma  and  Bhopalocoma  Salter  are 
probably  Cryptozonia  but  their  family  position  is  very  doubtful. 

Lepidaster  Forbes,  of  uncertain  affinities,  is  an  interesting  Silurian  genus 
with  large  disk  and  thirteen  rays.  Ethendgaster  Gregory,  from  the  Carboni- 
ferous  of  New  South  Wales,  is  considered  by  its  describer  as  a  related  genus, 
although  it  has  only  five  rays  and  was  originally  regarded  as  a  Palaeaster. 
Medusaster  Stürtz  is  notable  for  having  fourteen  rays,  and  Helianthaster  Roemer 
is  another  remarkable  form  with  sixteen  rays.  The  latter  has  been  regarded 
by  some  as  a  Starfish  and  by  others  as  an  Ophiuran ;  it  is  probable  that  it 
belongs  in  the  Cryptozonia,  but  most  unlikely  that  it  is  related  to  the  Recent 
South  American  Heliaster. 

It  is  possible  that  the  Recent  family  Linckiidae  isrepresented  in  the  Devonian 
by  Roemeraster  Stürtz,  but  the  relationship  is  very  dubious.  The  genera 
Palasteriscus  and  Echinasterella  of  Stürtz  from  the  Devonian  are  said  to  have  the 
madreporite  on  the  oral  side,  which  would  alone  render  them  worthy  of  note. 
Loriolaster  and  Cheiropteraster  Stürtz,  also  from  the  wonderful  Bundenbach 
slates,  are  possibly  allied  to  the  Recent  Pterasteridae.     Mesozoic  and  Tertiary 


252 


ECHINODERMATA— ASTEROZOA 


PHYLÜM  IV 


Cryptozonate  Asteroids  are  very  rare.  The  Recent  genus  Solaster  Forbes  is 
represented  by  a  species  with  numerous  arms  in  the  Great  Oolite  of  England. 
Two  important  families  of  Recent  Cryptozonia  are  the  Echinasteridae  and 
the  Asteriidae.  A  species  of  Echinaster  M.  and  T.  has  been  described  from 
the  Neocomian,  and  Forbes  thought  he  found  in  the  Red  Crag  of  England 
remains  of  the  now  common  Asterias  ruhens  Linn.  It  is  stränge  that  no  good 
evidence  has  been  found  of  the  occurrence  of  Asterias  in  Tertiary  strata. 


Olass  2.     OPHIUROIDEA  Gray.    Brittle  Stars.i 

Asterozoans  having  a  more  or  less  sharply  defined  central  disk  containing  a  simple 
digestive  cavity  which  does  not  radiale  into  the  slender  rounded  arms,  and  has  no  anal 
opening.  Reprodudive  organs  confined  to  the  disk.  Arms  with  an  axis  composed  of 
calcareous  Joint s,  the  elements  of  which  are  usually  fused  to  form  ^^  vertebral  ossicles" 
encased  with  plates  or  covered  with  a  leathery  skin,  and  very  rarely  with  open 
ambulacral  grooves.     Madreporite  constantly  on  the  actinal  {oral)  side  of  the  disk. 

AB  D 


Fig.  358. 
A,  Vertical  section  of  an  Ophiuran  arm.  w,  Vertebral  ossicle  ;  a,  Ambulacral  vessel,  witli  side-branches  lead- 
iiig  into  the  tube-feet ;  h,  Blood-vessel ;  tc,  Nerve-cord  ;  v.  Ventral  or  lower  arm-plate ;  I,  Side-plates  ;  d.  Dorsal 
plate.  B,  Vertebral  ossicle,  seen  from  the  inward  side,  with  surrounding  arm-plates.  C,  Row  of  vertebral 
ossicles  viewed  from  the  side,  and  slightly  enlarged  ;  x,  Apertures  where  the  branches  of  the  ambulacral  vessel 
enter  and  emerge  from  the  arm-bones  ;  i/,  Depressions  for  the  Insertion  of  intravertebral  muscles.  D,  Mouth- 
frame  of  an  Ophiuran,  with  the  proximal  vertebral  ossicles.  The  heavy  lines  bordering  the  arms  represent  the 
genital  slits  ;  the  dark  pentagon  in  the  centre  marks  the  course  of  the  nerve-ring. 

Ophiuroids  are  distinguished  from  the  typical  Starfishes  by  their  cylin- 
drical  flexible  arms,  which  are  sharply  separated  from  the  central  disk,  and 

1  Literature  :  Lütken,  C.  F.,  Additamenta  ad  historiam  Ophiuridarum.  Köngl.  dan.  Vidensk. 
Selskabs  Skrifter,  v.  and  viii.,  1858-69. — Lyman,  T.,  Ophiuridae  and  Astrophytidae.  Illustr.  Cat. 
Mus.  Comp.  Zool.  Cambridge,  Nos.  i.-iii.,  1865. — Ludwig,  IL,  Beiträge  zur  Anatomie  der 
Ophiuren.  Zeitschr.  für  wissensch.  Zool.,  vols.  xxxi.,  xxxiv.,  1878-80. — Ludwig,  H.,  Morphologische 
Studien  an  Echinodermen.  Leipzic,  1877-79.— Lyman,  T.,  Report  on  the  Ophiuroidea.  Challenger 
Expedition,  Zoology,  vol.  v.,  1882.  —  Picard,  K.,  Über  Ophiuren  aus  dem  oberen  Muschelkalk. 
Zeitschr.  deutsch,  geol.  Gesellsch.,  vol.  xxxviii.,  1886. — Boehm,  G.,  Beitrag  zur  Kenntniss  fossiler 
Ophiuren.  Berichte  naturf.  Gesellsch.,  Freiburg,  v.,  1889. — Gregory,  J.  W.,  On  the  Classification 
ofthe  Palaeozoic  Echinoderms  of  the  gTOup  Ophiuroidea.  Proc.  Zool.  Soc,  London,  1896. — Sollas, 
W.  J.,  On  Silurian  Echinoidea  and  Ophiuroidea.  Quart.  Journ.  Geol.  Soc. ,  1899,  vol.  Iv. — Hainann, 
0.,  Die  Schlangensterne.  Buch  iii.,  Abt.  3,  Bd.  2,  of  Bronn's  Klassen  und  Ordnungen  des  Tier- 
reichs, 1901. — Strassen,  0.  zur,  Zur  Morphologie  des  Mundskelettes  der  Ophiuriden.  Zool.  Anz., 
1901,  vol.  xxiv. — Jaekd,  0.,  Ästenden  und  Ophiuriden  aus  dem  Silur  Böhmens.  Zeitschr.  Deutsch. 
Geol.  Ges.,  1903,  vol.  Iv. — Parks,  W.  A.,  Notes  on  the  Ophiuran  genus  Protaster.  Trans.  Canad.. 
Inst.,  1909,  vol.  viii. — Sollas,  L  B.  J.  and  W.  J.,  Lapworthura  :  A  typical  Brittle-star  of  the 
Silurian  Age.     Phil.  Trans.,  1912,  vol.  ccii. 


JLASS  II 


OPHIUEOIDEA 


253 


I 

^■Üo  not  contain  diverticula  of  the  alimentary  canal  nor  of  the  sexual  organs. 
The  arms  serve  as  locomotive  organs,  and  are  either  elegantly  plated 
or  protected  by  a  coriaceous  skin,  in  which  minute  granules  and  scales  are 
embedded.  When  plated,  the  covering  consists  typically  of  four  rows  of 
calcareous  plates,  known  as  the  upper,  lower  and  side  arm-plates  (Fig.  358,  A). 
The  lateral  or  adamhulacral  plates  usually  carry  rows  of  mobile  spines. 

The  greater  part  of  the  interior  of  the  arms  is  occupied  by  a  linear  series  of 
jointed,  vertebra-like  sections  called  the  vertebral  ossicles  or  arm  bones,  each  of 
which  is  made  up  of  two,  or  possibly  of  four,  ambulacral  pieces  soldered  side 
by  side  (Fig.  358,  B,  C).  The  halves  of  the  first  two  vertebral  disks  are  swung 
laterally  into  the  interbrachial  space,  being  fused  together  to  form  the  mouth 
angle.  The  remainder  of  the  arm-bones  are  movably  articulated  with  one 
another  by  means  of  bosses  which  project  from  the  centres  of  both  surfaces, 
the  interspaces  being  fiUed  with  muscles.  The  entire  series  is  incised  inferiorly 
along  the  median  line  for  the  reception  of  the  radial  water-tube,  beneath 
which  runs  the  radial  blood-vessel  and  nerve  cord,  the  whole  being  closed  in  by 
the  integument.  The  radial  ambulacral  vessel  (water-tube)  gives  off  a  pair  of 
lateral  branches  in  each  arm  ossicle  which  pierce  the  bone  itself,  and  supply 


Fig.  359. 

Portion  of  central  disk  of  Ophiura  viewed 
from  the  dorsal  side.  a,  Radial  shields ; 
h.  Upper  arm-plates  ;  c,  Side  arm-plates. 


Portion  of  central  disk  of  Ophiura 
viewed  from  the  ventral  side.  a,  Mouth 
shield ;  b,  Side  mouth  shield ;  c,  Jaws 
bearing  papillae ;  g,  Genital  slits ;  h,  Side 
arm-plates ;  %,  Pores  for  the  emission  of 
the  tube-feet,  surroimded  with  tentacle 
scales ;  k,  Spines. 


the  tentacle-like  tube-feet  with  water.  The  tube-feet  are  without  either 
arapullae  or  terminal  suckers,  and  the  orifice  of  the  plates  through  which  they 
protrude  is  often  protected  by  one  or  more  minute  tentacle  scales  (papillae 
amhulacrales),  which  serve  to  cover  the  tentacles  when  they  are  drawn  in. 

On  the  under  side  of  the  disk  is  seen  the  central,  star-shaped  aperture  of 
the  mouth  (Fig.  363),  which  leads  into  a  large  sac-like  stomach.  The  latter 
terminates  blindly,  there  being  no  intestine.  The  body  cavity  also  contains 
the  ambulacral,  blood  and  nerve  rings,  as  well  as  the  generative  glands,  whose 
ducts  open  into  folded  pouches  or  bursae.  The  bursae  are  arranged  in  five 
pairs,  one  to  each  interbrachial  area,  and  communicate  with  the  extenor  by 
means  of  slit-like  fissures  (genital  slits),  which  skirt  the  arm  bases  mferiorly, 
and  are  bounded  by  genital  or  bursal  scales.  Sometimes  the  fissures  are 
discontinuous  (Ophioderma),  appearing  as  two  slits,  one  behind  the  other  ;  and  in 
some  fossil  forms  they  are  represented  by  rows  of  pores.         ^      ,.  .         ,    , 

The  integument  covering  the  entire  upper  surface  of  the  disk  and  the 
interbrachial  area  on  the  ventral  side  is  frequently  beset  with  calcareous 
plates  :  but  this  scale  coat  may  be  covered  in  turn  with  a  thick  skin,  or  bear 
spines  or  granules.  A  large  central  plate  is  sometimes  recognisable  on  the 
dorsal  aspect  of  the  disk,  together  with  five  pairs  of  plates,  which,  from  their 


254  ECHINODERMATA— ASTEEOZOA  phtlum  iv 

Position  at  the  points  of  origin  of  the  arms,  are  called  radial  shields 
(Fig.  359).  On  the  ventral  surface  of  the  disk,  the  inner  angle  of  each 
interbrachial  space  is  occupied  by  a  single  large  plate  termed  the  mouth 
shield  {scutum  buccale)  (Fig.  360),  one  of  which  serves  as  the  madreporic  body. 
But  in  the  Cladophiuroida  the  mouth  shields  are  often  feebly  developed,  or  may 
be  wanting  altogether ;  and  in  place  of  them  a  madreporite  is  f ound  in  one  or 
all  of  the  interrays.  The  mouth  shields  are  bounded  proximally  by  a  pair  of 
somewhat  smaller  plates  called  the  side  mouth  shields.  Finally,  within  the 
side  mouth  shields,  and  usually  pressing  against  them,  are  the  jaws  which  are 
sometimes  covered  by  the  skin  or  by  granulations  (Fig.  360).  Teeth  are 
constantly  present,  being  attached  to  the  jaw-plates  by  small  muscles,  and 
other  tooth-like  processes  (tooth-papillae  and  oral-papillae)  are  generally  present 
at  the  inner  angle  or  along  the  sides  of  the  jaws. 

A  natural  Classification  of  the  Ophiuroidea  remains  to  be  established. 
Those  who  have  worked  principally  on  Eecent  forms  have  not,  as  a  rule, 
proposed  any  completed  System ;  and  so  while  our  knowledge  of  the  number 
and  variety  of  Eecent  species  has  increased  enormously,  no  progress  has  been 
made  toward  a  rational  arrangement  of  the  class.  On  the  other  band,  some 
valuable  work  by  paleontologists  has  been  vitiated  by  ignorance  of  the  Eecent 
forms,  while  the  difficulties  of  the  material  with  which  such  work  must  be 
done  has  led  to  radical  differences  of  Interpretation  and  opinion. 

The  proposed  groups  Protophiuroidea  and  Euophiuroidea  may  be  natural 
divisions,  but  as  the  character  upon  which  the  class  is  differentiated  is  the  struc- 
ture  of  the  arm  and  the  development  of  "  vertebral  ossicles,"  the  Classification 
proposed  by  Bell  and  elaborated  by  Gregory  may  better  be  adopted  as  a 
basis  for  further  study.  Under  this  system  four  Orders  may  be  recognised, 
but  family  limits  are  uncertain  and  unsatisfactory.  The  termination  of 
Gregory's  ordinal  names  is  altered  to  end  in  -oida. 

Order  1.     LYSOPHIUROIDA. 

Ophiuroidea  in  which  the  vertebral  ossicles  are  incomplete,  the  two  halves  not 
being  united,  but  separate  and  alternate.  There  are  no  ventral  arm-plates  ^nd  thus 
a  more  or  less  distinct  ambulacral  furrow  is  present. 

This  Order  includes  a  group  of  Paleozoic  Asterozoans,  intermediate 
between  Ophiurans  and  Starfishes.  They  differ  from  the  latter  only  in  the 
general  form,  the  arms  being  sharply  set  off  from  the  disk,  but  probably  the 
alimentary  canal  and  reproductive  organs  were  confined  to  the  disk.  The 
characters  of  the  ambulacral  plates  are  often  uncertain,  but  they  may  be 
either  subquadrate  or  "  boot-shaped."  The  character  of  the  mouth-parts  in 
this  Order  and  the  next  has  been  well  worked  out  by  the  Sollases,  and  their 
primitive  character  clearly  shown.  The  principal  genera  are  Protaster  Forbes 
from  the  Silurian,  and  Bundenhachia  and  Palaeophiura  Stürtz,  from  the  Devonian 
of  Europe.  The  Ophiurans  from  the  Lower  Silurian  strata  of  Bohemia, 
whose  structure  is  discussed  by  Jaekel,  are  undoubtedly  members  of  this 
Order.     The  most  important  genus  is  Bohemura. 

Order  2.     STREPTOPHIUROIDA. 

Ophiuroidea  in  which  the  vertebral  ossicles  are  more  or  less  complete,  and  in 
any  case,  the  two  halves  are  opposite.     The  ossicles  articulate  with  each  other  by  ball- 


CLASS  II 


OPHIUROIDEA 


255 


and-socJcet  joints.  The  arm-plates  are  more  or  less  completely  developed  and  the  side 
arm-plates  may  carry  spines.  Arms  may  he  very  short  with  relatively  enormous 
tuhe-feet,  as  is  apparently  the  case  in  Eudadia. 

This  Order  includes  a  number  of  Paleozoic  forms  and  not  a  few  Recent 
species.  Important  genera  are  Ophiurina  Stürtz,  Devonian,  with  separate  am- 
bulacral   ossicles  and    no  ventral   arm-  ^ 

plates;  Lapworthura  Gregory,  Silurian, 
with  barely  fused  ambulacral  ossicles, 
and  no  ventral  arm-plates ;  Sympterura 
Bather,  Devonian,  similar  to  Lap- 
worthura, but  with  narrower  rays  and 
spinulose  disk ;  and  Eoluidia  Stürtz, 
Devonian,  with  fused  ossicles,  and  with 
ventral  arm-plates.  The  genus  Ony- 
chaster  Meek  and  Worthen  (Fig.  361), 
Lower  Carboniferous,  has  usually  been 
regarded     as     representative     of     the 

mndprn    Enrvalid«?    hnt  thp   oharaofpr  ni       OnychasterßexiUsM.  and  W.   Lower  Carboniferous ; 
moaern    JLUryaiiaS,    DUÜ  tne  Cnaracter  OI    Crawfordsville,Ind.(after  Meek  and  Worthen).  ^,In- 
the   ambulacral    ossicles    necessitates    itS    dividual  of  the  natural  slze  with  rolled  up  anns ; 
,       .         .        -  .  ,  ^,  111       ^'^^  dorsal  covering  of  the  central  disk  is  removed, 

incmSIOn  m  tniS  Order.       ine  remarkable    exposin^  the mouth  frame.   B,  Mouth  frame enlarged, 

Silurian  genera  Eudadia  Wood  ward,  and  ""'"'''^ ''"'"  "^"^'^ '  ^^'  '''''^''^"' '''''''''  ^"^"^«^• 
Euthemon  Sollas,  are  exceedingly  difficult  to  place,  and  their  relation  to  other 
Ophiurans  is  problematical. 


Fig.  361. 


Order  3.     CLADOPHIUROIDA. 

Ophiuroidea  in  ivhich  the  vertebral  ossides  are  complete  and  articulafe  with  each 
other  hy  means  of  hoiirglass-shaped  surfaces.  The  arms  are  oflen  dichotomously 
branched  and  lack  regulär  series  of  arm-plates. 

This  Order  includes  a  large  number  of  Recent  forms,  those  with  branched 


FiQ.  362. 
Aspidura  loricata  (Goldfuss).     Muschelkalk ;  Waschbach,  Würtemberg 
natural  size  (after  Quenstedt). 


A,  ßroup  of  individuals  of  the 
B,  Ventral  aspoct,  enlarged  (after  Pohlig). 


arms  (Astrophyton,  Gorgonocephalus,  Euryale)  being  known  as  "  Basket-fish  "  or 
"  Sea-spiders."  Fossil  forms  are  rare,  but  certain  Mesozoic  remains  of  doubt- 
ful  Position  have  been  referred  to  the  Recent  genera  Astrocnida  and  Euryale. 
Onychaster,  the  Streptophiuran  referred  to  above,  has  peculiarities  that  suggest 


256 


ECHINODERMATA -ASTEROZOA 


PHYLUM  IV 


this  Order,  but  the  form  of  the  ossicles  certainly  seems  to  exclude  it. 
Moreover,  Eudadia,  so  far  as  its  structure  is  known,  is  capable  of  very  diverse 
interpretations,  and  the  possibility  that  it  is  a  Starfish  rather  than  an 
Ophiuran,  must  not  be  wholly  ignored. 


Order  4.     ZYGOPHIÜROIDA. 

Ophiuroidea  with  simple  arms,  perfeäly  regulär  series  of  arm-plates  and  vertehral 
ossicles  fully  developed.  The  movement  of  the  ossicles  on  each  other  is  greatly  limited 
hy  the  development  of  lateral  processes  and  pits  on  their  articulating  surfaces. 


This  Order  includes  the  great  bulk  of  the  Kecent  Ophiurans  as  well  as 
^  those    of   the    Mesozoic   and  Tertiary. 

Indeed  some  of  the  Recent  genera  seem 
to  have  been  difFerentiated  as  far  back 
as  the  Jurassic,  and  Ophioderma  appar- 
ently  occurs  in  the  Triassic.  No 
Paleozoic  forms  can  certainly  be  re- 
ferred  to  this  group. 

The  genera  Aspidura  (Fig.  362) 
and  Acrura  Agassiz  are  occasionally 
abundant  in  the  German  Muschelkalk, 
and  certain  Liassic  Ophiurans  were 
also,  like  many  Recent  species,  notably 

Ophiocten  kelhevnunse  Böhm.     Lithographie  Stone ;  gregarioUS.         In      the      Lower,      Middle 

Kelheim,  Bavaria.     A,  Ventral  aspect  of  disk.     B,  i  TTnr^pr   Tnrn   nrA  fminrl  "Rrifflp  {^fnr« 

Dorsal  surface  of  one  of  the  arms.     (Both  figures  en-  ^^^^l  Upper  ÜUra  are  lOUnÜ  i^rittlC  ötarS 

larged  ;  original  in  Munich  Museum.)  closely    allied    tO    the    RcCCnt    OpMolcpis 

A  B 


Fig.  364. 

Geocoma  carinata  Goldf.  Lithographie  Stone ;  Zandt,  near  Solenhofen,  Bavaria.  A,  Individual  of  the 
natural  size.  B,  Dorsal  aspect  of  disk,  showing  granulations  and  central  depression.  C,  Ventral  surface  of  one 
of  the  arms.    (Figs.  B  and  C  enlarged.) 

M.  and  T. ;  Ophiocten  Ltk.  (Fig.  363);  Ophiura  Lamk.  (Figs.  359,  360);  and 
Ophiomusium  Lyman.  It  is  possible  that  some  of  these  are  really  congeneric 
with  Recent  species.  The  Mesozoic  genus  Geocoma  d'Orb.  (Fig.  364)  is  related 
to  the  Recent  Amphiura  Forbes,  but  there  can  be  little  doubt  that  some  of 
the  species  referred  to  it  are  based  on  material  which  cannot  be  determined 
so  precisely.  Lütken  considers  Ophiurella  elegans  Ag.,  from  the  Lithographie 
Stone  of  Solenhofen,  to  be  a  member  of  the  Recent  genus  Ophiocoma  Ag.,  but 


CLASS  I  ECHINOIDEA  257 

it  is  doubtful  whether  it  may  not  be  quite  as  properly  assigned  to  oiie  of 
several  other  genera.  Other  Jurassic  and  Cretaceous  forms  have  been 
assigned  by  Lütken  to  Ophium  Lamk.  (Ophioglypha  Lym.),  and  there  is  good 
reason  to  believe  that  the  genus,  in  a  broad  sense,  is  one  of  the  oldest  now 
living.  Fossil  Ophiurans,  whose  disk-covering  or  mouth  parts  cannot  be 
determined,  ought  not  to  be  assigned  to  Recent  genera,  but  all  such  and  all 
others  which  cannot  be  accurately  characterised  may  well  be  designated  by 
the  broad  term  Ophiurites. 

[The  text  for  the  foregoiiig  section  on  Asterozoa  has  been  revised  for  the  present  work 
by  Dr.  Hubert  Lynian  Clark,  of  the  Harvard  Museum  of  Comparative  Zoology,  at  Cambridge, 

Massachusetts.  — Editor.  ] 

SuBPHYLüM  C.     Echinozoa  Leuckart. 

Armless  and  non-pedunculate  Echinodermata,  with  glohular,  cordiform,  discoidal 
or  worm-like  bodies,  which  are  either  encased  in  a  plated  fest  or  are  invested  with  a 
leathery  integument,  emhedded  within  which  are  small-sized  detached  calcareous  bodies. 

Olass  1.     ECHINOIDEA  Bronn.    Sea-Urchin8.i 

Animals  possessing  a  wide  ränge  of  structure,  but  haxing  alimentaiy,  reproductive, 
nerve  and  water  vascular  systeins  within  an  enclosing  superficial  pentamerous  plated 
skeleton,  which  bears  movable  spines.  There  are  front  two  to  twenty  columns  of  plates 
in  each  of  the  five  ambulacral  areas,  and  from.  one  to  fourteen  columns  of  plates  in 

1  Literature  :  Agassiz,  L.,  and  JJesor,  E.,  Description  des  echinides  fossiles  de  la  Suisse,  1839- 
1840. — Catalogue  raisonne  des  familles,  genres,  et  des  especes  de  la  classe  des  echinides.  Aun.  des 
Sei.  Nat.,  1846-47. — cfOrUgny,  A.,  Paläontologie  fran^aise.  Terrains  cretacos  1853-55,  vol.  vi. — 
Cotteau,  G.  H.,  and  Triger,  Echinides  du  departement  de  la  Sarthe,  1857. — l)es(yr,  E.,  Synopsis 
des  echinides  fossiles.  Paris,  1858.  —  Wright,  T.,  Monograph  on  the  British  fossil  Echinodermata 
of  the  Oolitic  Forniations.  Palaeontograph.  Soc,  1857-78.— /f^em,  Cretaceous  Formations.  Palaeont. 
Soc,  1864-82. — Cotteau,  G.,  Paleontologie  franfaise,  vols.  vii. ,  ix.  and  x.,  1862-79. — Laube,  G.  C, 
Echinodermen  des  vicentischen  Tertiärgebietes.  Denkschr.  Akad.  Wiss.  Wien,  vol.  xxix.,  1868. 
— Loriol,  F.  de,  and  JJesor,  E.,  Echinologie  helvetique,  vols.  i.-iii.  Geneva,  lS%9i-%h.—Qnenstedt, 
F.  A.,  Petrefractenkunde  Deutschlands  (vol.  iii.,  Echinideu),  1872-75. — Agassiz,  A.,  Revision  of 
the  Echiui.  111.  Cat.  Museum  Comp.  Zool.  Cambridge,  No.  7,  1872-74.— Reports  on  the  Echini 
of  the  Hassler  (1874),  Challenger  (1881)  and  Blake  (1883)  Expeditions.— Z^^m,  S.,  Etudes  sur  les 
echinoidees.  Svensk.  Vetensk.  Akad.  Handl.,  vol.  xi.,  1874. — Cotteatc,  Peron,  and  Gauthier, 
Echinides  fossiles  de  l'Algerie.  Paris,  1876-91.— Loriol,  P.  de,  Monographie  paleontologique,  etc. 
Abhandl.  Schweiz.  Pal.  Gesellsch.,  1876-81,  vols.  iii.,  \m.— /James,  W.,  Die  Echiniden  der 
vicentischen  und  verouischen  Tertiär-Ablagerungen.  Palaeontographica,  1877,  vol.  xxv. — Agassiz, 
A.,  Palaeontological  and  Embryological  Development.  Proc.  Amer.  Assoc.  Adv.  Sei.,  1880. 
—Duncan,  P.  M.,  and  Sladen,  W.  P.,  Monograph  of  the  fossil  Echinoidea  of  Western  Sind. 
Palaeont.  Indica,  Ser.  xiv.,  1882-84:.— Schlüter,  C,  Die  regulären  Echiniden  der  norddeutschen 
Kreide.  Abhandl.  zur  geolog.  Special-Karte  von  Preussen,  vol.  iv.,  1883.— Jdem,  Neue  Folge, 
Heft  5,  1892. — Loriol,  P.  de,  Description  des  echinides.  Commission  des  travaux  gcol.  du  Portugal, 
1887-88,  vol.  iu—Loveu,  S.,  On  Pourtalesia.  Svensk.  Vetensk.  Akad.  Handl.,  1884,  vol.  xix.— 
Pomel,  jV.  A.,  Classification  mcthodique  et  genera  des  echinides  Vivantes  et  fossiles,  1883.— Duncan, 
P.  M.,  Revision  of  the  Genera  and  Great  Groups  of  the  Echinoidea.  Joum.  Liun.  Soc,  1889, 
vol.  yix\\\.—Loven,  S.,  Echinologica.  Bihang  tili  Svensk.  Vetensk.  Akad.  Handl.,  1892,  vol. 
xvm.— Clark,  W.  B.,  Mesozoic  Echinodermata  of  the  United  States.       Bull.   U.S.   Geol.  Survey, 

No.    97,    1893. Tornqnist,    A.,   Das   fossil  führende   Untercarbon   am    östlichen    Rossbergmassiv 

in  den  Südvogesen,  iii.,  Beschreibung  der  Echiniden- Fauna.  Abhandl.  Geol.  Special-Karte  Elsass- 
Lothringen,  1897,  vol.  v.  —  Mortensen,  T.,  Slam  Echinoidea.  Danske  Vidensk.  Selsk.  Skrift., 
1904,  vol.  i. — Bather,  F.  A.,  Triassic  Echinoderms  of  Bakony.  Resultate  der  wiss.  Erforsch.  Bala- 
tonsees, 1909,  vol.  l— Lambert,  J.  and  ThiSry,  P.,  Essai  de  nonienclature  raisonne  des  echinides. 
Chaumont,  1%Q9-Vl.-J<'cksnn,  R.  T.,  Phylogeny  of  the  Echini.  Mein.  Boslon  S,.r.  Xat.  llist., 
1912,  vol.  wn.—IL'wkliis,  II.  />.,  Chissification  of  tlie  Holectyponla.  itc  1»i.m-.  /,„,!.  >,„•. 
London,  1912. 

VOL.  I  ^ 


268 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


each  interamhulacral  area.  New  coronal  plates  are  formed  at  the  ventral  border  of 
the  five  ocular  plates,  ambulacral  pores  pass  through  amhulacral  plates,  rarely 
(Clypeastroids)  in  part  hetween  plates. 

The  peristome  is  on  the  under  or  actinal  surface,  and  in  all  but  the 
Exocycloida  bears  from  one  to  many  rows  of  ambulacral  plates  with  or  with- 
out  non-ambulacral  plates.  There  are  five  oculars  (apparently  in  part  or 
wholly  wanting  in  some  of  the  Pourtalesiidae),  and  five  genitals  or  fewer,  the 
whole  being  fused  into  a  mass  in  certain  types  of  Exocycloida.  The  genitals 
typically  have  each  one  or  more  pores  as  exits  of  the  interradiaÜy  situated 
reproductive  glands.  In  addition,  typically,  madreporic  pores  exist  in  genital 
2,  but  are  not  recognizable  in  most  Paleozoic  forms.  The  periproct  is  more 
or  less  plated,  situated  within  the  oculogenital  ring,  or  in  irregulär  types  out- 
side  of  that  area  in  the  posterior  interambulacrum ;  the  anus  is  in  the  peri- 
proct. The  masticatory  lantern  is  composed  of  forty  pieces  (or  Clypeastroids 
thirty  pieces) ;  it  is  wanting  in  adult  Spatangoids.  Respiratory  organs  consist 
of  Stewart's  organs,  peristomal,  or  ambulacral  gills.  Locomotion  is  eff'ected 
by  ambulacral  feet,  or  by  spines,  or  both. 

The  Test. — The  test  or  main  skeleton  of  the  Echini  is  composed  of  numerous 
calcareous  plates,  firmly  united  by  their  edges  so  as  to  form  a  more  or  less 

rigid  case  or  box  and  disposed  in  certain 
regions  or  Systems.  In  some  genera, 
however,  the  plates  overlap  one  another 
in  an  imbricating  manner  so  as  to  im- 
part  a  certain  degree  of  flexibility  to 
the  test.  When  coronal  plates  are 
imbricaie,  the  ambulacral  plates  overlap 
adorally  and  the  interamhulacral  over- 
lap aborally  and  from  the  centre  out- 
ward and  oyer  the  ambulacrals  on  the 
p^^,  gg^  adradial  suture  (Fig.  365).     When  peri- 

"  Lepidestiies  coiiettiyf\vL.   Synthetic  ii^ure  show-   stomal  plates  are  imbricate,  all  overlap 

ing  method  of  iinbrication  of  coronal  plates  (after    adorallv  (^Fi^    371     B^ 
Jackson).  rm  •  *         i    '  r       i 

ihe  main  element  oi  the  test  is 
termed  the  Corona,  which  is  composed  of  five  ambulacral  and  five  interam- 
hulacral areas.  At  the  summit  is  situated  the  apical  disc,  or  oculogenital 
plates,  which  in  regulär  Echini  surrounds  the  periproct  and  anal  opening. 
The  periproct  is  usually  plated,  always  carries  the  anal  opening,  and  in 
irregulär  Echini  lies  outside  of  the  apical  disk  in  the  posterior  interam- 
bulacrum. Yentrally  is  situated  the  peristome,  a  membrane  which  is  usually 
more  or  less  completely  plated,  or  may  be  naked,  and  extends  from  the 
mouth  opening  to  the  base  of  the  Corona.  The  peristome  is  either  central  in 
Position  or  anterior  to  the  centre  in  some  of  the  Exocycloida. 

Echini  are  oriented  by  an  antero-posterior  axis  drawn  through  an  ambul- 
acrum  and  opposite  interambulacrum  in  such  a  plane  that  the  madreporite  lies 
in  the  right  anterior  interambulacrum.  This  is  the  axis  on  which  bilaterality 
is  attained  in  the  Exocycloida,  and  the  same  axis  is  indicated  in  regulär  Echini 
by  the  order  in  which  ocular  plates  reach  the  periproct  when  such  occurs. 
With  known  axes  Lovön  devised  a  nomenclature  of  areas  which  is  of  very 
great  value  in  brevity  and  clearness  of  expression.     He  numbered  the  ambul- 


CLA8S  I  ECHINOIDEA  269 

acral  areas  from  I  to  V,  Koman,  and  the  interambulacra  from  1  to  5,  Arabic. 
The  enumeration  passes  from  left  to  rightj  revolving  like  the  hands  of  a 
watch,  the  specimen  beirig  viewed  from  below  and  the  odd  anterior  ambulacrum 
being  III  (Fig.  370).  When  viewed  from  above,  the  order  of  enumeration  is 
necessarily  reversed  (Fig.  434).  Lov6n  showed  that  the  size  and  character  of 
the  primordial  ambulacral  plates  give  data  by  which  a  sea-urchin  can  be 
oriented  in  young  regulär  Echini,  and  usually  in  adult  Exocycloida.  He 
showed  that  of  these  teil  plates,  the  la,  IIa,  Jllb,  lYa,  Yb  are  larger ;  on  the 
contrary  the  Ib,  Hb,  lila,  lYb,  Ya  are  smaller  (Figs.  370;  377,  A). 

The  mouth  opens  into  an  Oesophagus  which  conducts  into  a  capacious 
stomach,  and  thence  into  a  convoluted  intestine.  The  digestive  tract  winds 
around  the  interior  of  the  test,  being  attached  to  the  inner  surface  of  the 
latter  by  muscles,  and  terminates  in  the  anus.  Surrounding  the  Oesophagus 
is  a  circular  vessel  filled  with  water,  which  is  admitted  by  the  so-called  stone- 
canal,  opening  externally  in  a  madreporite.  This  is  a  porous  ör  sieve-like 
structure,  consisting  of  a  variable  number  of  canals,  and  though  commonly 
restricted  to  genital  2,  madreporic  pores  as  a  Variation  may  extend  to  additional 
genitals  or  to  ocular  plates. 

The  circular  vessel  gives  off  five  branches,  known  as  the  radiating  canals, 
which  pass  along  the  ambulacral  areas  on  the  interior  of  the  test,  and  con- 
nected with  it  in  the  interambulacral  areas  are  five  distensible  membraneous 
reservoirs,  termed  the  Polian  vesicles.  The  radiating  canals  give  off  numerous 
lateral  branches  or  tube-feet  (tentacles)  which  are  extended  through  the 
pores  of  the  ambulacral  plates.  Dilation  is  effected  by  means  of  secondary 
vesicles  or  ampullae  which  by  contraction  force  their  contained  fluid^  into  the 
tube-feet  and  distend  them.  The  ampullae,  as  a  rule,  communicate  with  the 
tube-feet  by  two  canals  perforating  the  plates  separately,  a  single  tentacle 
being  placed  pver  .a  pair  of  ambulacral  pores.  The  tube-feet  serve  usually 
as  locomotive  organs,  when  they  are  prehensile  and  end  in  a  suctorial  disk ; 
but  in  many  forms,  especially  those  having  petaloid  ambulacra,  they  are 
modified  so  as  to  be  partly  brauch ial  in  function.  Sometimes  the  tentacles  of 
the  same  ambulacrum  differ  in  shape,  structure  and  function,  as  in  Arbacia. 

Eespiration  is  apparently  effected  by  Stewart's  organs  in  certain  Echini. 
These  organs  are  internal,  five  in  number,  and  situated  radially,  they  are 
given  off  from  the  periphery  of  the  lantern  membrane  and  beneath  the  com- 
passes.  In  the  Cidaroida,  Stewart's  organs  are  frondescent;  in  the  Echino- 
thuriidae,  vermiform  or  sausage-shaped.  External  branchiae  or  gills  exist  in 
the  Centrechinoida  as  outward  extensions  of  the  oral  integument.  They  exist 
as  ten  small  or  larger  branched  fleshy  organs  interradially  situated.  Their 
presence  is  marked  by  indenting  cuts  in  the  basicoronal  plates  so  that  their 
presence  is  recognizable  in  fossils  where  they  exist  (Centrechinoida).  In 
Clypeastroids  and  Spatangoids,  as  well  as  partially  in  some  of  the  Centre- 
chinoida {Arbacia),  the  function  of  respiration  is  maintained  by  modified 
dorsal  ambulacral  tentacles  which  have  lost  their  function  as  locomotive 
organs.     For  distinction  these  are  called  ambulacral  gills. 

The  vascular  System  consists  of  a  ring-like  vascular  plexus  surrounding  the 
Oesophagus,  and  immediately  underlying  the  circular  ambulacral  vessel.  This 
ring  gives  off  five  radial  vessels,  and  also  two  others  which  send  off  branches 
to  the  stomach  and  generative  organs.  The  central  nerve  ring,  with  its  five 
principal  nerves  running  down  the  rays,  is  external  to  the  two  other  Systems. 


260  ECHINODERMATA— ECHINOZOA  phylum  iv 

The  generative  organs  are  superficially  alike  in  both  sexes,  and  are  in  the  form 
of  glands  (usually  five,  sometimes  four,  three,  or  even  two),  situated  dorsally 
and  interradially  on  the  inner  surface  of  the  test.  The  genital  ducts  terminate 
in  pores  in  the  so-called  genital  plates,  to  be  described  presently. 

Coronal  Plates. — The  plates  of  the  Corona  are  arranged  in  ten  meridional 
areas.  Five  of  these,  the  ambulacral  areas,  are  composed  of  perforated  plates, 
and  correspond  in  position  to  the  radiating  ambulacral  vessels  ;  the  remaining 
five,  the  interambulacral  or  interradial  areas,  alternate  with  the  first,  and  are 
imperforate. 

In  all  Recent  and  in  the  majority  of  fossil  Echini  the  ambulacral  areas  are 
each  composed  of  two  columns  of  alternately  arranged  plates,  the  inner 
edges  of  which  meet  in  a  zigzag  median  suture,  and  the  actinal  and  abactinal 
edges  in  horizontal  sutures.  In  some  Paleozoic  genera  there  are  more  than 
two  columns  in  an  ambulacral  area,  and  there  may  be  as  many  as  sixteen,  or 
even  twenty,  at  the  mid-zone  (Fig.  367,  o).  The  interambulacral  areas  are 
each  composed  of  from  one  to  fourteen  columns  of  plates,  but  nearly  all 
post-Paleozoic  and  all  Recent  types  have  two  columns.  Interambulacral  plates 
are  usually  larger  than  ambulacrals  and  meet  the  latter  in  vertical  adradial 
sutures.  There  are  therefore  from  fifteen  vertical  columns  of  coronal  plates, 
Bothriocidaroida  (Fig.  377,  A),  to  twenty  columns  Cidaroida,  Centrechinoida, 
Exocycloida,  or  more  than  twenty,  as  in  the  Paleozoic  Echinocystoida  and 
Perischoechinoida  (Figs.  429,  432),  and  the  Triassic  Plesiocidaroida.  One 
additional  case  of  more  than  twenty  columns  is  known  in  the  peculiar 
Cretaceous  Tetracidaris.  The  number  of  columns  of  plates  is  the  same  for  an 
individual  in  each  of  the  ambulacral  areas,  and  usually  for  each  of  the 
interambulacral  areas  as  well,  but  the  two  Systems  are  entirely  independent 
of  one  another  as  respects  the  size  and  number  of  plates  in  a  vertical  column, 
also,  especially  in  the  Paleozoic,  as  regards  the  number  of  columns  in  an  area. 
In  the  Cidaridae,  for  example,  the  ambulacra  are  very  narrow  and  are 
composed  of  numerous,  thirty  to  sixty  low  plates  in  a  column ;  the  inter- 
ambulacra  are  broad  with  few,  five  or  six  to  fifteen  high  plates  in  a  column. 
On  the  other  hand,  in  the  Paleozoic  Lepidesthes  colletti,  the  ambulacra  are 
broad,  with  sixteen  columns  of  plates  in  each  area,  and  the  interambulacra 
are  narrow  with  four  columns  in  each  area  (Fig.  434).  In  the  regulär  or 
endocyclic  Echini,  all  of  the  ambulacra  and  all  of  the  interambulacra  are 
essentially  similar  in  the  individual ;  but  in  irregulär  or  exocydic  Echini,  the 
anterior  ambulacrum  and  the  posterior  interambulacrum  often  differ  consider- 
ably  from  the  corresponding  areas. 

Interambulacral  (interradial)  plates  are  always  simple ;  ambulacral  plates 
may  be  either  simple  or  Compound.  In  the  latter  case,  they  are  formed  of 
two  or  of  several  component  elements,  all  of  which  are  joined  by  sutures  and 
form  a  more  or  less  geometrical  plate.  Most  simple  plates,  and  some  of  the 
components  of  Compound  plates  are  primaries — that  is,  they  extend  from  the 
outer  edge  of  an  ambulacrum  to  the  median  suture  of  the  area.  Demi-plates 
is  a  name  applied  to  those  component  elements  which  reach  the  inter- 
ambulacrum but  do  not  extend  to  the  median  suture  (Fig.  396).  Isolated 
plates  are  component  elements  which  do  not  reach  either  to  the  interam- 
bulacral or  median  suture.  Occluded  plates  are  component  elements  which 
reach  the  median  suture,  but  do  not  reach  the  interambulacrum.  These 
terms,   based    on    Compound    plate    elements,    can    be    also    applied   to    the 


CLASS  I 


ECHINOIDEA 


261 


characters  seen  in  Paleozoic  types  which  have  many  columns  of  simple  plates 
(Fig.  367,  l-o). 

The  growth  of  the  corona  of  all  Echini  is  effected  by  new  plates  being 
successively  added  at  the  dorsal  termination  of  the  ambulacra  and  inter- 
ambulacra,  and  by  their  increasing  in  size.  In  the  young,  and  in  adults 
where  the  ventral  border  of  the  corona  has  not  been  resorbed  in  the  advance 
of  the  peristome,  there  is  a  single  plate,  which  is  the  primordial  interambulacral, 
in  the  basicoronal  row  bordering  the  peristome  in  each  area  (Clypeastroids, 
Spatangoids,  many  Paleozoic  genera)  (Fig.  366,  a,  h,  f-h,  etc.).  Excepting 
the  Bothriocidaroida,  we  find  passing  dorsally  from  the  primordial  inter- 
ambulacral plate  that  new  columns  are  progressively  added  until  the  füll 
number  characteristic  of  the  order,  genus  or  species  is  attained.  The  new 
columns  come  in  in  a  perfectly  definite  order  and  System,  although,  where  a 
large  number  of  columns  is  attained,  there  is  some  local  Variation  as  regards 
the  point  of  introduction  and  also  the  number  of  columns.  As  progressive 
development  is  marked  by  the  addition  of  columns,  senescent  or  regressive 
development  is  marked  dorsally  in  some  types  by  the  dropping  out  of  columns 
(Figs.  429,  B ;  432).    The  primordial  interambulacral  plate  ventrally  represents 


.  Fio.  366. 

Characters  of  the  base  of  the  interambulacrinn  in  lepresentative  Echini :  a,  Bothriocidaris  arcMica  Jackson. 
Ordovician.  b,  Goniocidaris  canaliculata  A.  Agassiz.  Young.  c,  Euddaris  tribuloides  (Lamarck).  Bahamas. 
d,  Melonechinus  multiporus  (Norwood  and  Owen).  Lower  Carboniferous.  e,  Archaeocidaris  woHheni  Hall. 
Lower  Carboniferous.  /,  Echinocyamus  pusillus  (Müller).  Recent.  g,  Rotula  dentata  (Lamarck).  Recent. 
h,  Perlschodomus  Usericdis  M'Coy.  Lower  Carboniferous.  In  figures  a,  b,  f-h,  the  primordial  interambulacral 
plate  is  in  the  basicoronal  row  ;  in  c-e,  it,  with  or  without  additional  plates,  has  been  resorbed  (after  Jackson). 

a  Single  column,  and  may  be  compared  with  the  adult  of  the  Ordovician 
Bothriocidaris  which  retains  a  single  column  in  each  area  throughout  life. 
The  ventral  border  may  in  the  adult  be  retained  intact,  or  it  may  have  been 
more  or  less  extensively  resorbed  in  the  advance  of  the  peristome.  When 
this  occurs,  the  primordial  interambulacral,  with  or  without  additional  rows 
of  plates,  are  cut  away.  Such  occurs  in  the  Cidaroida,  most  of  the  Centre- 
chinoida,  and  a  number  of  Paleozoic  genera  (Fig.  366,  c-e). 

Ambulacra. — Each  ambulacrum  has  two  columns  of  simple  or  Compound 
plates,  or  in  some  Paleozoic  genera,  more  than  two  columns  of  simple  plates. 
The  ambulacrum  is  always  composed  of  two  halves  which  are  equal  on  either 
side  of  the  median  suture.  Ambulacral  pores  are  typically  in  pairs,  rarely 
(some  Spatangoids)  unpaired.  Pore-pairs  usually  lie  nearer  to  the  inter- 
ambulacral suture  than  to  the  middle  of  the  plate  in  which  they  occur, 
therefore  as  a  result,  where  there  are  two  columns  of  ambulacral  plates, 
there  is  a  median  interporiferous  area  between  two  marginal  poriferous  areas. 
The  pores  of  a  pair  may  be  vertically  superposed,  or  usually  the  upper  pore 
of  a  pair  revolves  outward,  through  an  angle  of  90"  or  less,  and  toward  the 
interambulacrum,  so  that  the  axis  of  the  pair  is  inclined  or  horizontal,  the 
inner  pore  being  the  lower  of  the  two.  A  pore-pair  is  typically  surrounded 
by  an  elevated  rim  or  peripodium,  and  the  pores  of  a  pair  may  be  united  by 
transverse  furrows,  when  they  are  said  to  be  conjugate. 


ECHINODEBMATA— ECHINOZOA 


PHYLUM  IV 


The  arrangement  of  pore-pairs  is  uniserial  when  one  pair  is  placed  over 
the  other  in  a  continuous  lirie  from  the  peristome  to  the  apex ;  hiserial  when 
so  placed  that  there  are  two  vertical  rows  of  pore-pairs  in  each  half-area, 
and  polyserial  when  there  are  three  to  many  vertical  rows  of  pore-pairs  in  a 
half-area.  When  ambulacral  plates  are  componnd,  the  pore-pairs  of  each 
component  element  may  be  arranged  in  an  are,  when  there  results  a  biserial 
or  polyserial  arrangement.  In  Paleozoic  genera,  where  the  structure  of  the 
ambulacrum  is  complex  with  many  columns  of  plates  {Melonechinus),  the 
ventral  portion  is  simpler,  presenting  stages  of  development  through  which 
the  animal  has  passed.  In  the  same  types  the  dorsal  area  of  young  last 
added  plates  also  shows  simplicity  as  a  localised  stage  in  development.  In 
those  types  that  have  Compound  ambulacral  plates,  the  young  plates  dorsally 
are  simple  for  a  short  distance,  as  seen  well  in  Centrechinus. 


Fig.  367. 

Character  of  the  ambulacrum  in  representative  Echini ;  left  half  represented,  The  horizontal  dotted  line  is 
on  the  plane  of  the  mid-zone  (after  Jackson),  a,  Bothriocidaris  archaica  Jackson.  Ordovician.  b,  Goniocidaris 
canaliculata  A,  Ag.  Young.  c,  Eucidaris  tribuloides  (Lamarck).  Bahamas,  d,  Strongylocentrotus  dröbachiensis 
(O.  F.  Müller).  Young.  e,  The  same  ;  Adult.  York  Harbor,  Maine.  /,  Micraster  cor-anguineum  (Lamarck). 
Cretaceous,  England,  g,  Echinarax;hnius  -parma  (Lamarck).  Eastport,  Maine,  h,  Metalia  pectoralis  (Lamarck). 
Bahamas ;  showing  plates  of  two  areas.  i,  Palaeechinus  elegans  M'Coy.  Lovver  Carboniferous.  k,  Maccoya 
hurlingtonensis  (Meek  and  Worthen).  Lower  Carboniferous.  l,  Lovenechinus  missouriensis  (Jackson).  Lower 
Carboniferous.  m,  Oligoporus  danae  (Meek  and  Worthen).  Lower  Carboniferous.  n,  Melonechinus  multiporus 
(Norwood  and  Owen).     Lower  Carboniferous.     o,  Lepidesthes  colletti  White.     Lower  Carboniferous. 


Ambulacra  are  usually  band-shaped  and  continuous  from  the  peristome 
to  the  apical  disc.  Petaloid  ambulacra  are  those  which  enlarge  between 
the  apex  and  the  circumference  (ambitus),  and  contract  again  more  or 
less  perfectly  before  reaching  that  region.  Suhpetaloid  ambulacra  are  more 
elongated  than  the  petaloid,  and  the  series  of  pairs  of  pores  do  not  tend  to 
close  distally.  The  pores  do  not  cease  altogether  at  the  end  of  the  petaloid 
parts,  but  remain  traceable  for  some  distance  beyond,  often  as  far  as  the 
peristome.  In  such  cases,  however,  the  pores  are  greatly  reduced  in  size,  or 
present  other  marked  differences  from  those  of  the  petaloid  parts.  The 
poriferous  areas  are  said  to  be  discontinuous,  or  inferrupted,  when  the'  pairs  of 
pores  cease  at  the  ends  of  the  petals,  and  reappear  in  the  vicinity  of  the 
peristome. 

Oculogenital  or  Apical  System. — This  is  abactinal  or  dorsal,  and  is  ordinarily 
composed  of  ten  plates,  five  oculars  and  five  genitals,  forming  usually  (ex- 
cepting  some  Echinothuriidae,  always  in  regulär  Echini)  a  continuous  ring. 
The  genitals  are  typically  large  angular  plates  interradially  situated  and 
perforated  by  one  or  more  pores  communicating  with  the  genital  glands.  One 
of  the  genitals,  the  right  anterior,  is  also  perforated  by  madreporic  pores 


CLASS  I 


ECHINOIDEA 


263 


rhich  serve  in  orienting  a  specimen.  These  madreporic  pores  are  rarely 
recognizable  in  Paleozoic  Echini,  and  may  have  been  wanting  in  some  genera. 
In  the  Exocycloida  the  posterior  genital  is  usually  imperforate  or  wanting, 
and  two  or  more  to  all  genitals  may  be  fused  in  a  mass.  Genital  plates 
may  be  in  contact  dorsally,  forming  a  closed  ring,  or  may  be  in  part  or  wholly 
separated  by  the  oculars. 

Ocular  plates  dorsally  cover  the  ambulacra  and  laterally  the  inter- 
ambulacra  in  part  on  either  side.  Each  ocular  has  a  single  pore.  In 
Paleozoic  forms,  oculars  are  apparently  imperforate  or  rarely  with  two  pores. 
The  pores  are  related  to  a  primitive  large  tentacle  and  not  to  an  ocular  organ. 
Ocular  plates  may  all  separate  the  genitals,  reaching  the  periproct,  when  they 
are  described  as  insert,  the  usual  Paleozoic  character  (Fig.  433,  ^) ;  or  they 
may  be  all  excluded  from  the  periproct  by  the  contact  of  the  genitals,  when 


Fig.  368. 

Typical  ocular  plate  arraiigement  in  regulär  Echini  (after  Jackson).  A,  Cidaris  coronata  Goldfuss.  Upper 
Jura  ;  Sontheim.  All  oculars  exsert ;  plates  shaded.  B,  Salenocidaris  profundi  (Duncan).  Eecent ;  Tristan 
da  Cuiiha.  Ocular  I  insert ;  plates  shaded.  C,  Acrüsaleniaspinosa  A^&ssiz.  Cornbrash;  Chippenhani,  England. 
Ocular,s  I,  V,  insert.     D,  Centrechinus  setosus  (Leske).     Recent ;  Bermuda.    Oculars  I,  V,  IV,  insert. 

they  are  described  as  exsert,  the  usual  Mesozoic  character  (Fig.  368,  A). 
Oculars  are  all  exsert  in  the  young  of  probably  all  Recent  and  Mesozoic 
regulär  Echini.  In  adults  the  same  character  may  obtain,  or  one  or  more  to 
all  oculars  may  travel  in  with  development,  separating  the  genitals  so  as  to 
be  insert.  As  shown  by  Jackson,  when  oculars  become  insert,  they  do  so  in  a 
definite  sequence  in  relation  to  the  antero-posterior  axis.  The  first  ocular  to 
become  insert  is  either  I,  or  V.  If  ocular  I  comes  in  first,  then  V  follows,  or 
the  converse,  thus  marking  the  posterior  pair  or  the  bivium  ;  next  ocular  IV 
becomes  insert,  then  II,  thus  marking  the  posterior  pair  of  the  anterior 
trivium ;  lastly,  if  at  all,  ocular  III  becomes  insert  (shown  in  part  in  Fig.  368, 
A-D). 

The  apical  disk  is  relatively  large  in  very  young  Echini  and  in  primitive 
types  {Bothriocidaris,  Cidaroida).  It  decreases  rapidly  proportionately  in  size 
with  growth,  and  is  relatively  small  in  specialised  regulär  Echini  {Echinometra, 
Melonechinus,  Lepidesthes,  Fig.  434). 

In  the  Exocycloida  the  genital  plates  may  be  in  contact  at  their  sides, 
forming  a  compact  System  (Fig.  369,  D) ;  or  they  may  be  separated  by  some  of 
the  ocular  plates  which  meet  along  the  median  line  and  separate  the  posterior 
genitals,  forming  an  elongate  System  (Fig.  369,  C).  When  the  two  posterior 
ambulacra  (bivium)  do  not  terminate  at  the  summit  in  line  with  the  other  three 


264 


EGHINODERMATA— ECHINOZOA 


PHYLUM  IV 


(trivium),  and  are  surmounted  by  oculars  placed  far  posteriorly,  the  System  is 
Said  to  be  disjimä  or  disconneded.     The  posterior  oculars  are  then  separated 

from    the    postero- 
'  ^'  ^  ^  lateral  genitals  by 

a  number  of  inter- 
ambulacral  plates 
intercalated  along 
the  dorsum  (Fig. 
369,  A). 

In  the  Clypea- 
strina  and  many 
of  the  Cassidulidae, 
the  apical  System 
consists  of  five 
minute  ocular 
plates,  and  one 
large,  pentagonal, 
central  plate,  which 
probably  represents 
the  fused  genitals 
and  is  usually 
pierced  in  four  or 
in  all  of  its  inter- 
radial angles  by 
genital  pores  (Fig. 
369,  E,  F). 
Periproä. — This  structure  which  bears  the  anus  is  within  the  apical  disk 
in  all  regulär  Echini,  when  the  test  is  termed  endocyclic ;  and  at  a  variable 
distance  beyond  it  in  the  median  line  of  the  posterior  interambulacrum  in 
irregulär  Echini,  when  the  test  is  termed  exocydic.  Periproctal  plates  are 
rarely  preserved  in  fossil  Echini.  They  are  numerous,  angular,  thick,  and 
fill  the  area  in  Paleozoic  genera  and  the  Cidaroida ;  they  are  numerous,  or 
few  and  dissociated,  often  reduced  to  granules  in  other  Echini ;  or  the 
periproct  may  be  largely  leathery  (CentrecMnus).  In  the  Saleniidae  there  is  a 
large  suranal  (Fig.  368,  B),  with  additional  large  plates  (some  Acrosalenias)  or 
with  small  plates  only.  A  suranal  occurs  in  the  young  of  some  types  as  the 
Echinidae  and  Strongylocentrotidae.  The  periproct  is  usually  circular,  but  may 
be  angular,  or  in  the  Exocycloida  varies  from  circular  to  elliptical  or  pyriform. 
The  Position  of  the  periproct  in  the  test  is  of  great  systematic  importance. 

Peristome. — This  is  actinal  and  central  in  regulär  Echini,  and  is  circular, 
decagonal  or  pentagonal  in  outline.  Along  its  margin  in  the  basicoronal 
interambulacral  plates  of  the  corona  there  are  ten  incisions  for  the  extension 
of  the  peristomal  gills  which  exist  in  certain  Echini,  the  Centrechinoida  and 
Holectypina.  In  the  Exocycloida  the  peristome  is  variable  in  shape  and 
Position,  but  it  is  actinal  and  is  central  or  more  or  less  anterior  from  the 
centre.  The  oral  membrane  of  the  peristome  is  attached  to  the  lantern  when 
present,  otherwise  the  inner  edge  is  free. 

The  peristome  may  be  more  or  less  extensively  plated  or  may  be  naked, 
and  the  character  of  the  plates  is  of  systematic  importance.  In  the  young  of 
probably  all  regulär  Echini  there  is  one  row  of  primordial  ambulacral  plates 


Apical  Systems  of  irregulär  Sea-iirchiiis.     A,  CoUyrites.     B,  Holectypua. 
C,  Hyboclypeus.    D,  Micraster.     E,  Conodypeus.     F,  Clypcaster. 


CLASS  I 


ECHINOIDEA 


265 


which  are  found  in  place  and  fill  the  area  (Fig.  370).     From  this  primitive 

condition  various  departures  exist.     The  area  may  be  filled  with  two  or  many 

rows   of    ambulacral    plates   only   {Bothrioci- 

daris,  Fig.  377,  ^  ;  Hyattechinus,  Fig.  429,  ^  ; 

Phonnosoma,    Fig.    371,    A).     These    plates 

after  the  first  row  have  doubtless  been  de- 

rived   by  migrating   down  from   the  Corona 

as  shown  by  Loven.      There  may  be  many 

rows    of    ambulacral    with    interradial    non- 

ambulacral  plates  (Cidaroida,   Fig.   371,  B; 

Archaeocidaris,    Fig.    371,    C ;    Melonechinus, 

Fig.   371,  D).     There   may    be   one   row  of 

ten  primordial  ambulacral  plates  with  more 

or    less    solid,   scaly,   or   isolated   non-ambu- 

lacral   plates,   or   rarely   no  non- ambulacral 

plates  (most  Centrechinoida).     There  may  be 

scaly   non -ambulacral   plates   only    (Spatan- 

goids),  or  the  peristome  may  be  quite  naked 

of  plates  (Clypeastroids) 

AristoÜe's  Lantern 
exception  of  Spatangoids  (and  possibly  some 
Holectypoids)  are  provided  with  a  powerful 
masticatory  apparatus  known  as  the  Aristotle's  lantern,  which,  with  the  muscles 
and  their  points  of  insertion  in  the  test  are  of  high  systematic  value.  The 
lantern  is  composed  of  forty  pieces  in  all  Echini  except  Clypeastroids.   *  There 


Fig.  370. 

Goniocidaris  caTUÜiculata  A.  Agassiz.  Re- 
cent ;  Falkland  Islands.  Young,  1.45  mm.  in 
diameter.     Primordial  ambulacral  plates  tili 


All    -n   T_'    •        'J.I,    j.1^      •tli'^    peristome,    primordial    interambulacral 
-AU    lliCnini  Wltn    ttie    plates  in  the  basicoronal  row  succeeded  by 


two  plates  in  the  second  row  in  each  inter- 
radial area  (after  Jackson). 


Fk!.  371. 
Characters  of  peristome  and  base  of  the  corona  in  representative  Echini.  J,  Phormosoirm  plucenta 
Wyville  Thomson.  Recent ;  otf  Cape  May  to  Cape  Sable.  On  the  peristome  many  rows  of  ambulacral  plates. 
/>',  Kucidaris  tnbuloides  (Lamarck).  Bahamas.  On  the  peristome  many  rows  of  ambulacral  and  in  addition 
interradial  non-ambulacral  plates.  C,  Archaeocidaris  tnortheni  Hall.  Lower  Carboniferous.  Partially  restored. 
On  the  peristome  many  rows  of  ambulacral  and  in  addition  interradial  non-ambulacral  plates.  /),  Melonechinus 
multiporus  (Norwood  and  Owen).  Lower  Carboniferous.  Restored.  On  the  peristome  many  rows  of  ambulacral 
and  in  addition  two  rows  of  interradial  non-ambulacral  plates ;  ambulacrals  pass  from  two  plates  orally  to 
manv  on  the  periphery  of  peristome  in  each  area.  E,  Strongylocentrotus  dröbachiensis  (O.  F.  Miiller).  York 
Harbor,  Maine.  On  the  peristome  one  row  of  ambulacral  and  scattered,  small,  non-ambulacral  plates.  ±, 
Krhinocardium  flavescens  (Müller).  Recent.  On  the  peristome  many  non-ambulacral  plates  only.  In  hgures 
A  and  F  the  primordial  interambulacral  plates  are  in  place  in  the  basicoronal  row  ;  in  the  other  hgures  they  have 
been  resorbed,  with  or  without  additional  plates  (after  Jackson). 

are  five  teeth ;  five  pyramids,  each  composed  of  two  halves,  joined  by  suture ; 
ten  epiphyses ;  five  braces ;  and  five  compasses,  each  composed  of  two  parts, 
joined  by  suture.  The  lantern  is  inclined,  subtending  an  angle  of  about 
90",  in  the  young  of  modern  and  adult  of  Paleozoic  Echini ;  erect  with  sides 
approaching  the  vertical  in  most  Recent  regulär  Echini ;  or  procumbent  in 
most  Clypeastroids.  Teeth  are  grooved  (Paleozoic  genera,  Cidaroida  and 
Aulodonta);    or   have   a  keel   on   the  inner  face  (Stirodonta,   Camarodonta, 


266 


ECHINODERMATA— ECHINOZOA 


PHYLÜM  IV 


B 


Holectypina,  Clypeastrina).     Pyramids,   each   composed  of    two  halyes,    are 
roughly  triangulär  in   section,  present   a   median   suture,   above   which  is   a 

shallow  or  a  deep 
open  Space,  the 
foramen  magnum. 
On  the  inner  face 
the  pyramid  Sup- 
ports and  embraces 
the  tooth,  and 
laterally  in  regulär 
Echini  has  ridges 
for  the  attachment 
of  interpyramidal 
Fig.  372.  muscles.         The 

Dental  apparatus  of  the  Recent  Strongylocentrotus  dröbachiensis  (O,  F.  Müller).  UDDer   faCC    of    the 

A,  Lantern  showing  teeth,  pyramids,  interpyramidal  muscles,  styloid  processes  of  ^^       .  , 

dental  slides,  epiphyses,  crests  and  compasses.     B,  Pyramid  showing  on  one  side  pyramiu,     aS     Seen 

protractor  and  retractor  muscles,   epiphysis  removed   on  left  side.     C,   top  of  ^.'Up«     ^-'Up    p-nmhv 

lantern,  at  areas  2,  3  a  whole  tooth  in  place  ;  at  1  pulj)y  i)art  of  tooth  removed  ;  at  Wneil     lim    epipuy- 

4  tooth  removed.    At  area  III  compass,  brace  and  epiphyses  in  place  ;  at  V  com-  gjg    jg    remOVed     is 

pass  removed  ;  at  IV  brace  also  removed  ;  at  I  the  epiphysis  of  one  side  is  removed  ' 

to  show  pits  in  top  of  pyramid.     2/^  (after  Jackson).  a        smOOth        IlOOr 

(Paleozoic  genera, 
Cidaroida) ;  or  is  pitted  (Centrechinoida).  An  epiphysis  caps  each  half- 
pyramid,  to  which  it  is  joined  by  close  suture,  it  presents  a  glenoid 
cavity  and  tubercles  for  interlocking  with  the 
brace.  The  epiphyses  are  narrow  in  all  Echini 
except  the  Camarodonta  in  which  they  are  wide 
and  meet  in  suture  over  the  foramen  magnum ; 
here  also  they  bear  crests  which  support  the  teeth 
dorsally.  The  brace  is  a  block-shaped  plate  which 
rests  on  and  interlocks  with  the  epiphyses.  The 
compass  rests  on  the  brace  and  consists  of  an  inner 
and  an  outer  part,  joined  by  suture;  the  outer 
part  is  usually  bifid  but  may  be  rounded.  The 
angle   of  'inclination    of    the    lantern,    the    teeth 

grooved  or  keeled,  the  depth  of  the  foramen  mag-     py,^^id  „f  Recent  strongyiocen- 
num,  absence  or  presence  of  pits  in  the  top  of  the  ^™^«*'  dröbacUensis.   a,  in  sid«  view 

.,  ^        ^  .^  .  11«      showing  corrugations  for  attachment 

pyramids,  and  narrow  or  wide  epiphyses  and  their  of  interpyramidal  muscie,  epiphysis 

.^^^-,-     .,•  ,  •  i.       2.  £      j.  •!•     with  crest,  glenoid  cavity,  external 

meetmg  in  suture  are  important  f eatures  in  classi-  and  internal  tubercles.   b;  Pyramid 

fication  from  centre  showing  dental  slide  and 

*    ,  other  parts  as  in  A  (after  Jackson). 

The  ]aws  of  the  Holectypoids  are  similar  to 
those  just  described,  but  in  the  Clypeastroids  they  are  low,  often  asym- 
metrical,  and  the  teeth  are  aslant  or  even  nearly  horizontal  (Fig.  374). 
Compasses  are  absent,  and  the  braces  are  rudimentary.  The  pyramids  are 
solid  almost  to  their  upper  part,  more  or  less  concave,  or  re-entering  on  the 
outer  side,  and  are  not  always  of  the  same  size  in  each  area.  Jaws  of 
Echini  are  rarely  preserved  in  the  fossil  State. 

The  muscles  of  the  lantern  are  numerous  and  complex,  and  their  insertion 
in  the  test  is  of  systematic  importance.  There  are  sixty  lantern  muscles  in 
regulär  Echini  which  in  brief  are,  ten  protractors  inserted  on  the  outer  face 
of  the  pyramids  and  base  of  the  test ;  they  extend  the  lantern  ;  ten  retractors 
similar ly  situated  which  open  the  jaws  (Fig.  372,  B) ;   five  interpyramidal 


Fig.  373. 


CLASS  I 


ECHINOIDEA 


267 


Fia.  374. 

A,  Clypeaster  reticulatus  Loven.  Kecent.  The  dental  System  entire,  seen  from 
above.  The  braceß  are  placed  upon  the  sutures  of  adjoiiiing  pyramids,  with  an 
epiphysis  on  either  side.  Teeth  in  line  with  the  mesial  sutures  of  half-pyramids, 
and  within  the  ring  formed  by  the  supra- alveolar  crests  (after  Loven).  B,  a,  Front 
View  of  a  Single  pyramid  ;  b,  side  view  of  one  of  the  half-pyramids. 


muscles  (Fig.  372,  A)  which  contract  the  jaws ;  teri  internal  and  ten  external 
brace  muscles,  which  are  tiny  and  extend  from  the  brace  to  the  epiphyses ; 
live  circular  compass  muscles  which  dorsally  connect  the  com  passes ;  ten  radial 
compass  muscles 
which  extend 
from  the  com- 
pass to  the  base 
of  the  test. 
These  last  are 
wanting  in  Cly- 
peastroids  as  in 
that  group  com- 
passes  are  ab- 
sent. 

Perignathic 
Girdle.  —  Cer- 
tain  muscles  of 

the  lantern,  namely,  the  retractor,  protractor  and  radial  compass,  pass  to  and 
are  inserted  on  the  base  of  the  test,  and  certain  important  processes,  the 
perignathic  girdle,  may  be  built  for  insertion  of  these  muscles.  Lov6n  showed 
that  in  young  Goniocidaris  the  lantern  muscles  are  all  attached  directly  on  the 
base  of  the  interambulacra,  and  the  same  method  probably  existed  in  the 
Perischoechinoida,  as  in  that  order  no  perignathic  processes  have  been  seen. 
In  adult  Cidaroida  elevated  processes,  the  apophyses  exist  as  strong  internal 
upgrowths  of  the  ventral  border  of  the  basicoronal  interambulacral  plates ;  to 
these  apophyses  in  this  order  alone  are  attached  the  retractor,  protractor  and 
radial  compass  muscles.  In  the  order  Centrechinoida  the  apophyses  or  up- 
growths of  the  interambulacral  plates  m-ay  be  feebly  or  strongly  developed,  and 
to  them  are  attached  the  protractor  and  radial  compass  muscles.  In  this  order 
a  new  structure  appears  consisting  of  two  separate  calcareous  plates,  the 
auricles,  which  are  united  by  close  suture  to  the  basicoronal  ambulacral  plates. 
The  auricles  exist  as  separate  styles  or  in  some  genera  in  development  may 
grow  into  large  plates  which  arch  and  join  in  suture  over  the  ambulacral  area. 
Auricles  give  insertion  to  the  retractor  muscles,  which  combination  of 
apophyses  and  auricles  is  known  in  this  order  only.  In  the  Holectypoids 
low  apophyses  and  auricles,  or  auricles  alone  may  exist ;  as  this  group 
occurs  fossil  only,  the  muscles  can  only  be  inferred.  In  Clypeastroids 
apophyses  are  wanting,  but  low  or  high  auricles  exist  on  the  ambulacral 
plates,  or  even  may  be  transferred  to  the  basicoronal  interambulacral  plates 
as  seen  in  Echinarachnius.  In  Clypeastroids  retractor  and  protractor  muscles 
are  both  inserted  on  the  auricles,  a  condition  peculiar  to  the  group. 

Tubercles  and  Spines. — The  plates  of  Echini  bear  more  or  less  numerous 
tubercles  and  granules  of  various  sizes  which  bear  larger  or  smaller  spines. 
The  larger  and  completely  developed  tubercles  are  called  primaries;  those 
of  a  smaller  size  are  secondaries;  and  very  small  tubercles,  sometimes 
incomplete  in  their  development,  are  miliaries.  Granules  are  irregulär  or 
nodular  projections  of  the  test;  they  may  be  large  and  widely  separated, 
or  very  numerous  and  of  various  sizes.  The  base  of  a  tubercle  is  termed 
the  boss,  and  its  upper  part  may  be  either  piain  or  crenulated.  The  boss 
Supports  a  rounded  mamelon,  which  is  said  to  be  perf<yrated  when  pierced  by  a 


268 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


Cidarid  Spines.     A,  B,  Cidaris.    D,  Acrocidaris. 
E,  Porocidaris  (natural  size). 


central  foramen  for  a  slight  distance,  or  imperforate  when  it  is  not.  A  piain 
or  sunken  space  surrounding  the  base  of  the  tubercle  is  called  the  scrobicule, 
or  areola ;  its  outer  limit,  the  scrohicular  circle,  is  generally  marked  by  a  ring 

^  oi  granules,  but  in  many  cases  the 
scrobicules  of  the  same  meridian  are 
continuous.  Secondary  tubercles  may 
or  may  not  be  scrobiculate. 

All  the  tubercles  of  Echini  bear 
movable  spines,  which  differ  greatly  in 
dimensions,  and  in  the  shape  and 
nature  of  their  cross-sections.  They 
are  usually  cylindrical,  acicular,  clavate 
or  spatulate  in  form,  and  consist  of 
the  following  parts  :  A  more  or  less 
elongate  distal  portion  or  shaft ;  a  base, 
to  which  ligaments  are  attached  for 
keeping  the  spine  in  place ;  and  an 
articulating  Joint  or  condyle  (acetabulum), 
forming  a  ball -and -socket  Joint  with 
the  tubercle  proper.  When  the  base 
of  the  mamelon  is  crenulated,  the  base 
of  the  spine  is  incised  in  the  same 
manner,  and  above  the  latter  is  usually  a  milled  ring  or  collar,  the  indenta- 
tions  of  which  are  continuous  with  the  Striae  of  the  shaft.  The  function  of 
spines  is  to  support  the  test,  to  aid  in  locomotion,  and  for  defence.  In  rare 
cases  some  of  the  spines  are  fixed,  and  arise  directly  from  the  test  (Recent 
Podocidaris). 

Fascioles  are  narrow  bands  of  close  granulär  ornamentation  which 
support  rudimentary  spinules  and  pedicellariae.  They  occur  only  in  the 
Spatangoids,  and  are  restricted  to  certain  parts  of  the  test.  The  peripetalous 
fasciole  follows  the  margin  of  the  petaloid  parts  of  the  ambulacra.  The 
anal  fasciole  surrounds  the  anus,  and  the  subanal  fasciole  encloses  a  space  or 
plastron  beneath  the  anus,  but  may  send  anal  branches  upward.  The  internal 
fasciole  crosses  the  ambulacra  at  a  variable  distance  from  the  apical  System, 
and  the  marginal  fasciole  encircles  the  test  above  the  ambitus.  For  those 
Spatangoids  with  subanal  fascioles,  Loven  has  proposed  the  name  Prymno- 
desmia ;  genera  without  them,  and  with  other  fascioles,  are  Prymnadetes,  and 
those  without  any  fascioles  are  Adetes. 

Pedicellariae  are  small  specialised  organs  articulated  upon  granules  and 
scattered  between  the  spines  over  the  whole  test.  At  the  end  of  the  stem 
is  a  head  consisting  of  two  or  more  pincer-like  valves  which  function  as 
grasping  and  cleansing  organs.  Pedicellariae  are  very  rarely  preserved  in 
the  fossil  State. 

Sphaeridia  are  opalescent  spheroidal  bodies  which  may  be  partially  or 
entirely  covered  by  the  test.  They  exist  singly  near  the  ventral  border  of 
the  ambulacra,  or  if  more  than  one,  the  series  extends  dorsally,  even  to  the 
ocular  plate.  Morphologically,  sphaeridia  may  be  considered  as  modified 
spines  having  sensory  functions.  They  are  known  only  in  the  Centrechinoida 
and  Exocycloida. 

-The  early  larval  stages  of  Echini  are  similar  in  many  respects 


CLASS  I  ECHINOIDEA  269 

to  those  of  Ophiurans  and  Starfishes,  but  have  little  in  common  with  the 
larvae  of  Crinoids.  The  later  stages  in  development  are  of  great  morpho- 
logical  and  phylogenetic  interest.  Stages  in  development  can,  of  course,  be 
best  obtained  by  studying  young  individuals,  but,  as  shown  by  Jackson, 
they  can  also  in  a  measure  be  obtained  from  a  study  of  adults.  The  plates 
at  the  ventral  portion  of  the  test  are  the  oldest  and  first  formed,  excepting 
as  some  may  have  been  resorbed  in  the  advance  of  the  peristome.  Ventrally, 
therefore,  stages  in  development  are  often  observable  in  both  the  ambulacra 
and  interambulacra,  this  condition  being  especially  marked  in  the  Perischo- 
echinoida.  Dorsally  are  found  the  youngest  plates  of  the  test,  and  it  is  here 
that  we  observe  localised  stages  in  development.  For,  as  we  pass  ventrally 
to  the  progressively  older  plates,  it  is  found  that  characters  are  taken  on 
in  regulär  sequence  which  present  stages  directly  comparable  to  those  seen 
in  the  youthful  development  of  the  individual.  Dorsal  localised  stages  are 
especially  marked  in  the  ambulacra  of  those  types  where  a  complex  structure 
is  attained,  as  in  the  Palaeechinidae  and  the  Centrechinoida.  The  apical  disk, 
periproct,  peristome,  lantern  and  perignathic  girdle  all  show  stages  in 
development  with  suitable  material,  which  stages  are  directly  comparable 
to  adult  conditions  of  simpler  members  of  the  group,  and  therefore  are  of 
great  phylogenetic  significance. 

Among  Echinoids,  as  elsewhere  in  invertebrate  groups,  evidence  is  accumu- 
lating  that  evolutionary  Variation  is  not  radial  in  all  directions,  but  rather  is 
in  definite  directions,  or  orthogenetic.  It  would  appear  that  the  majority  of 
variations  are  either  arrested,  in  which  cases  the  variant  retains  characters 
displayed  in  its  own  youthful  stages  and  typical  of  the  adults  of  more  primi- 
tive allies ;  or  progressive,  when  the  variant  has  characters  not  typical  of  the 
species,  but  which  are  further  evolved  in  the  direct  line  of  difFerential  develop- 
ment. These  latter  are  seen  typically  in  more  highly  evolved  closely  related 
species  or  genera.  In  order  to  study  Variation  intelligently  it  is  of  prime 
importance  to  be  familiär  not  only  with  the  characters  of  the  associated 
species  and  genera  when  considering  any  given  case,  but  also  with  the  develop- 
mental  characters  of  the  same.  Variation  needs  to  be  especially  considered  in 
undertaking  phylogenetic  studies. 

Homologies. — The  Echinoidea  differ  radically  from  the  Pelmatozoa  and 
Asterozoa  in  that  arms  are  completely  wanting.  They  differ  from  Crinoids  in 
that  reproductive  glands  are  within  the  test  and  interradial,  that  ambulacral 
and  interambulacral  plates  originate  on  the  ventral  border  of  a  fixed  plate,  the 
ocular,  and  in  the  possession  of  a  lantern.  Echinoids  differ  from  Starfishes 
essentially  in  that  radial  water,  nerve  and  blood  canals  are  on  the  proximal  not 
distal  side  of  the  ambulacral  plates ;  that  ambulacral  pores  pass  through,  not 
between  the  plates ;  and  in  the  possession  of  a  lantern. 

Habits. — Echini  are  exclusively  marine,  and  are  more  or  less  gregarious. 
Many  species  occur  in  littoral  zones,  and  from  that  region  various  species  and 
genera  extend  to  continental  and  abyssal  depths.  Echini  commonly  live  on 
the  surface  of  the  sea  floor,  or  cling  to  rocks.  Some  Echini  burrow  in  sand, 
others  (Strongylocentrotus,  Echinometra)  along  the  coast  occur  in  cavities  which 
they  bore  in  solid  rocks.  The  same  species  does  not  excavate  in  sheltered 
places. 

-  About  500  recent  species  are  known,  as  compared  with  fully  2500  fossil. 
The  earliest  types  appear  in  Ordovician  rocks  (Bothriocidaris),  and  continue  to 


270  ECHINODERMATA— ECHINOZOA  phylum  iv 

be  represented  sparsely  throughout  the  Paleozoic  era.  They  multiply  enor- 
mously  in  the  Mesozoic,  and  certain  families  reach  their  climacteric  in  that 
period ;  other  families  attain  their  maximum  in  the  Recent.  As  a  rule,  the 
species  have  a  very  limited  vertical  ränge,  and  hence  serve  admirably  as  index 
fossils.  The  test  is  often  perfectly  preserved,  but  even  small  fragments  are 
capable  of  accurate  determination,  owing  to  the  regulär  radial  repetition 
of  parts. 

The  Classification  here  followed  is  based  on  that  given  in  Jackson's 
Phylogeny  of  the  Echini;  no  subclasses  are  recognised,  but  the  group  is 
divided  into  seven  Orders.  The  generic  descriptions  of  the  Cidaroida  and 
Centrechinoida  and  the  generic  and  family  descriptions  of  the  Exocycloida  are 
essentially  those  as  given  in  the  earlier  edition  of  this  work,  or  in  Duncan's 
Revision  of  the  Genera  and  Great  Groups  of  the  Echinoidea. 


Order  1.     BOTHRIOCIDAROIDA  Duncan. 

Test  regulär,  more  or  less  spherical.  Interamhidacra  with  one,  and  ambulacra 
with  two  vertical  columns  of  plates,  which  do  not  imbricate.  Feriproä  within  the 
apical  System. 

Family  1.     Bothriocidaridae  Klem. 

JFith  characters  of  the  order. 

The  solitary  known  genus  is  Bothriocidaris  Eichwald  (Figs.  366,  a;  367, 
a;  376;  377),  from  the  Ordovician  of  Esthonia.     The  test  is  small,  and  the 


Fig.  376. 

Bothriocidaris  pahleni  Schmidt.     Ordovician;  Nömmis,  Esthonia.     ^,  Test  of  the  natural  size.     J5,  Apical 
System,  enlarged.     C,  Peristome,  enlarged  (after  F.  Schmidt). 

apical   System  consists   of  five   large   ocular  and  five  small  genital   plates ; 
periproct  plated,  peristome  with  ambulacral  plates  only. 

Of  this  important  genus,  the  oldest  of  known  Echini,  there  are  three  species,  B.  archaica, 
pahleni  and  globulus.  The  ambulacra  have  two  columns  of  high  hexagonal  plates  in  each 
area  with  pore-pairs  superposed  in  a  central  peripodium.  Interambulacra  with  one  column 
of  plates  only  in  each  area.  Ocular  plates  relatively  large  and  meeting  in  a  continuous  ring 
{£.  archaica),  or  partially  or  wholly  separated  by  the  small  genitals.  Genitals  in  £.  archaica 
dorsal  to  the  oculars  (Fig.  377,  B)  or  in  other  species  partially  or  wholly  separating  them  and 
reaching  the  interambulacra,  Bothriocidaris  is  structurally  important  because  in  its  high 
ambulacral  plates,  with  pores  superposed,  its  single  column  of  interambulacral  plates,  its 
simple  peristome  and  its  large  oculars,  it  presents  features  like  the  young  of  later  Echini.  All 
other  Echini  start  with  a  single  interambulacral  plate  ventrally,  representing  a  single  column, 
and  later  add  one  or  more  columns.  Those  types  with  only  two  columns  of  plates  in  an  inter- 
ambulacral area  show  no  evidence  of  beiug  derived  from  types  with  many  columns,  and  are 
therefore  considered  as  next  related  to  the  Bothriocidaroida. 


CLASS  I 


ECHINOIDEA 


271 


Order  2     CIDAROIDA  Duncan. 

Test  regulär,  endocycUc,  two  columns  of  plates  in  each  ambulacral  area,  ambula- 
cral  plates  low,  simple;  ftvo  (in  one  genus,  Tetracidaris,  partly  föur)  columns  of 


A,  Bothriocidaris  archaica  Jackson.  Ordovician ;  Island  of  Dago,  Russia.  Height,  12  mm.  Two  rows  of 
peristomal  plates.  Two  columns  of  hexagonal  plates  in  each  ambulacrum.  One  column  of  plates  in  each  inter- 
ambulacrum.  x  3/j.  B,  the  same,  apical  disk,  oculars  meeting  in  a  ring,  genitals  small,  dorsal  to  the  oculars,  peri- 
proctal  plates.     x  ^/i  (after  Jackson). 

plates  in  each  interamhulacral  area.  Coronal  plates  rarely  imbricate  (Miocidaris). 
Primordial  interamhulacral  plates  resorhed.  Peristome  with  many  rows  of  ambulacral 
and  interradial  non-ambulacral  plates,  or  rarely  ambulacral  plates  only.  Lantern 
erect,  teeth  grooved,  foramen  magnum  very  shallow  ;  epiphyses  narrow.  No  pits  in 
the  top  of  pyramids.  Perignathic  girdle  consisting  of  apophyses  only.  Stewarts 
Organs  ptresent,  but  no  peristomal  gills.  Primary  spines  with  a  cortical  layer. 
Primary  tubercles  perforate.     Sphaeridia  absent. 


272 


ECHINODERMATA— ECHINOZOA 


PHYLÜM  IV 


Family  1.     Cidaridae  Gray. 

With  charaders  of  the  order. 

The  apical  disk  is  rare  in  fossil  Cidarids  (Fig.  368,  A) ;  when  preserved,  the 
ocular  plates  are  typically  all  exsert.  The  same  conditiori  exists  in  the  young 
of  Recent  species  and  often  in  adults.  When  oculars  reach  the  periproct, 
they  do  so  in  the  sequence  V,  I,  IV,  II,  III,  or  V,  I,  IV,  III,  II.  Young 
Cidarids  approach  Bothriocidaris  closely  in  many  structural  details.  De- 
vonian  (?),  Lower  Carboniferous  to  Recent ;  maximum  in  Jura  and  Cretaceous. 


Section  A.     Ambulacral  pore-pairs  uniserial. 

Miocidaris  Döderlein.     Ambulacral  and  interambulacral  plates  imbricating. 
Two  Paleozoic  species,  M.  keijserUngi  (Geinitz),  from  the  Permian  of  Europe, 


Fig.  378. 

Cidaris  coronata  Goläit  Upper  Jura  (y);  Hossingen,  Wurtemberg.  A,  Dorsal  aspect  of  test  with  perfectly 
preserved  apical  System.  B,  Profile.  C,  Portion  of  Amh,  magnified.  Z),  Partially  restored  view  with  spines 
attached. 

and  M.  cannoni  Jackson,  from  the  Lower  Carboniferous  of  America,  are  the 
only  certain  Paleozoic  representatives  of  the  order.  Several  species  in  the 
Trias  and  Jura  of  Europe. 

Cidaris  Leske,  ex  Klein  (Figs.  368,  A  ;  378-380).  Amb  undulating  or  nearly 
straight,  the  pores  variable  in  their  distance,  and  united  by  a  groove  or  not. 
lAmb  coronal  plates  five  to  fifteen  in  each  column.  Apical  system  large. 
Primary  spines  very  variable,  even  in  the  same  species.  Trias  to  Recent ; 
chiefiy  Jurassic  and  Cretaceous. 

Of  this  genus  more  than  200  species  have  been  described.  These  are  grouped  into  seven 
or  eight  artificial  divisions,  whicli  are  regarded  by  some  as  of  sub-generic,  or  even  generic 
importance.     Some  of  the  groups  may  be  briefly  noticed  as  follows  : — 


CLASS  I 


ECHINOIDEA 


273 


(a)  Rhabdocidaris  Desor  (Figs.  381,  382).  Test  large  and  swollen.  Poriferous  areas  wider 
than  in  Cidaris,  tlie  two  pores  of  a  pair  being  distant  and  conjugated.  Amb  in  general 
straight.  Tiibercles  large,  strongly  crenulated,  and  more  nunierous  than  in  Cidaris.  Spines 
very  stout,  some  cylindrieal  or  prismatic,  often  spiniferons.  Chiefly  Jura  and  Cretaeeous  ; 
less  common  in  Tertiary  and  Recent. 


Fio.  379, 

Eucidaris  tribuloides  (Lam.).     Receiit.     Erilarged  vievv  of  base  of  the 
test  and  peristome,  showing  plated  coveriug  of  the  latter. 


Plf!.  380. 

Cidarid  spines.  A 
C.  alata  Ag.  ß,  C 
dorsata  Braun.  Trias 
St.  Cassian,  Tyrol 
C,  C.  florigemma  Phill 
Coral  llag ;  Wiltshire. 


Fig.  381. 

Rhaf}docldaris  orUgnyana  Desor.  Upper 
Jura;  Kelheim- Winzer,  Bavaria,  ^.Frag- 
ment of  test,  i/i.    B,  Amb  plates  enlarged. 


Fio.  382. 

Rhabdocidaris  horrida 
Morian.  Middle  Jura. 
Spine,  i/i. 


{b)  Leiocidaris  Desor.  Like  the  preceding,  but  with  uncrenulated  tubercles.  Spines 
large,  smooth,  cylindrieal.     Cretaeeous  to  Recent. 

(c)  Stephanocidaris  A.  Ag.  Test  thin  ;  apical  System  larger  than  the  peristome,  the 
plates  feebly  united.     Recent. 

{d)  Pliyllacanthus  Brandt.  Test  large,  swollen,  and  witheight  to  eleven  lAmb  plates 
in  a  column.     Amb  broad,  pores  conjugated.     Primary  tubercles  large,  smooth.     Recent. 

(e)  Porocidaris  Desor  (Fig.  383).  Amb  broad  and  straight ;  pores  wide  apart,  conjugated. 
Primary  tubercles  perforate  and  crenulate.  Scrobicules  transversely  oval,  with  shallow 
grooves  radiating  from  the  periphery  toward  the  centre,  with  or  without  pores  at  the  outer 
extremity  of  the  grooves.     Tertiary  and  Recent. 

(/)  Goniocidaris-  Desor.  Töst  high,  with  nunierous  coronal  plates,  and  narrow  Amb. 
The  median  sutural  regions  of  both  areas  are  sunken,  forming  with  the  horizontal  sutures 
a  zigzag,  with  pit-like  depressions  at  the  angles.     Recent. 

VOL.  I  T 


274 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


Orthocidaris    Cotteau.     Apical    System    small,    pentagona!.     Amb   narrow, 
straight ;    pore-pairs    in    simple    straight    series,    the    pores   separater!    by    a 
granule.     lAmb  very   broad,   numerously  plated.     Primary 
tubercles  small,  piain,  perforate  and  distant.     Lower  Creta- 
ceous ;  Europe. 

Temnocidaris  Cotteau.  Upper  Cretaceous.  Polycidaris 
Quenst.     Upper  Jura. 

Section  B.  Amhulacral  Pore-pairs  Biserial. 

Diplocidaris  Desor.  Test  large,  spheroidal.  Amb  narrow, 
straight.  Pore-pairs  very  numerous,  close,  alternating  more 
or  less.  lAmb  broad,  with  seven  to  eight  plates  in  each 
column.  Primary  tubercles  large,  perforate,  scrobiculate. 
Upper  Jura ;  Europe. 

Tetracidaris  Cotteau  (Fig.  384).  Remarkable  in  having 
four  columns  of  plates  in  each  lAmb  at  the  ambitus,  but 
diminishing  to  two  at  the  apex.  Amb  straight,  moderately 
broad.  Poriferous  areas  depressed,  pairs  incompletely 
biserial ;  interporiferous  areas  narrow,  granulär,  with  a  row 
of  piain  small  tubercles,  placed  near  the  borders  of  the 
poriferous    zone.      lAmb     primary    tubercles    very    large, 

crenulate  and  perforate.     Spines  narrow,  elongate.     Lower  Cretaceous  (Bar- 

remien);  Europe. 


Fig.  383. 

Forocidaris  schmiedeli 
Goldf.  Numraulitic 
Liniestone;  Mokkatain, 
nearCairo.  lAmb -plate 
and  spine. 


Fi(i.  384. 

Tetracidaris  reynesi  Cotteau.     Neocomian  ;  Vergans,  near  Castellane,  Basses  Alpes.     A,  Test  reduced 
one-half.     B,  Portion  of  Amh,  enlarged  (after  Cottean). 

Xenocidaris  Schnitze.      Founded  upon  clavate,  fusiform   spines   from   the 
Devonian  of  the  Eifel.     Incompletely  known,  possibly  belongs  in  this  family. 


Order  3.     CENTRBCHINOIDA  i  Jackson. 

Test    regulär,    endocyclic,     two    columns    of  plates    in   each    ambulacral    area, 
ambulacral  plates  Compound,  rarely  simple;  two  columns  of  plates  in  each  inter- 

^  This  name  is  based   on   Gentrechinus,  a  new  narae  for  Diadema  which  was  preoccupied  for  a 
Crustaceaii. 


CLASS  I  ECHINOIDEA  275 

amhulacral  area.  Primordial  amhulacral  plates  arouml  the  mouth  in  tlie  peristome. 
Primordial  inter amhulacral  plates  in  the  basi-coronal  row,  or  usually  resorhed. 
Peristome  lüith  ten  primordial  amhulacral^  also  non-amhulacral  plates,  or  in  one 
family  many  rows  of  amhulacral  plates  only.  Lantern  erect  or  rarely  inclined ; 
teeth  grooved,  or  keeled  :  foramen  magnum  deep.  Pits  in  the  top  of  pyramids. 
Perignathic  girdle  consisting  of  low  or  high  apophyses,  and  auricles.  Peristomal  gills, 
rarely  with  Stewarts  organs  in  addition.  Primary  spines  without  a  cortical  layer. 
Sphaeridia  present. 

Compound  amhulacral  plates  are  the  most  striking  feature  of  this  order ; 
such  plates  are  composed  of  from  two  to  ten  elements,  each  of  which  has 
a  pore-pair.  The  young  of  the  Centrechinoida  present  stages  in  development 
which  closely  resemble  the  Cidaroida  and  also  Bothriocidaris.  The  Centre- 
chinoida are  divisible  into  three  suborders  on  the  basis  of  the  structure  of  the 
lantern,  which  is  in  brief,  teeth  grooved,  epiphyses  narrow,  Aulodonta ;  teeth 
keeled,  epiphyses  narrow,  Stirodonta ;  teeth  keeled,  epiphyses  wide,  meeting  in 
suture  over  the  foramen  magnum,  Camarodonta.     Trias  to  Recent. 


Suborder  A.     AULODONTA  Jackson. 

Teeth  grooved.  Epiphyses  narrow,  not  meeting  in  suture  over  the  foramen 
magnum.  Amhulacral  plates  simple  or  Compound.  Oculars  all  exsert,  or  hecoming 
insert  in  the  sequence  /,  V,  IV,  II,  III.  Periproct  with  many  plates  or  granules, 
or  largely  leathery.  Lantern  erect  or  inclined.  Primary  tubercles  usually  perforate. 
Trias  to  Recent. 

Family  1.     Hemicidaridae  Wright. 

Amhulacral  plates  Compound  ventrally,  simple  above  the  mid-zone,  or  in  sonie 
genera   Compound    throughout.     Coronal  plates    thick,    not    imbricating.     Base  of 
Corona  resorhed,     Oculars  all  exsert,   or   one,    or   two  may    he  insert.     Periproct 
unknown.     Peristome  unknown.     Lantern  erect.     Trias 
to  Tertiary. 

Hemicidaris  Agassiz  (Fig.  385).  Amh  narrow  ; 
plates  near  the  apical  system  very  numerous,  small, 
low  primaries,  succeeded  by  plates  formed  of  from 
two  to  four  components,  together  with  additional 
primary  or  demi-plates.  Tubercles  in  two  vertical 
rows,  perforate  and  crenulate.  lAmh  broad,  with 
two  vertical  rows  of  tubercles  similar  to  those  of  p^^.  gg^ 

t\vQ  Amh,  but  much  larger.     Oculars  all  exsert  or      hemicidaris   crenuiaris   (Lam.). 

I,     or     I,     V     insert.        Peristome     large,     with     well-    Coral  Rag;  ChätelCensoire,  Tonne. 

developed  branchial  incisions.     Trias  to  Cretaceous.   ^  ^' 
The  following  subgenera  are  recognised  : — 

(a)  Hemidiadema  Ag.  Amh  tubercles  large,  and  few  in  number  below  the  ambitus, 
alternating  distinetlj.     Jura  and  Cretaceous.     H.  stramonium  Ag. 

{h)  Hypodiadema  Desor.  Amh  narrow,  straight ;  their  tubercles  of  nearly  the  same  size 
througliout.     Peristome  and  branchial  incisions  small.     Trias  to  Cretaceous. 

(c)  Pscudocidaris  Etall.  Amh  very  undulating  abactinally,  with  primary  tubercles  near 
the  peristome,  granules  elsewhere.     Jura  and  Cretaceous. 

Acrocidaris  Ag.  (Fig.  386).     Test  large,  spheroidal  dorsally,  flat  actinally. 


276 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


Amb  straight,  broad  at  the  ambitus ;  pore-pairs  uniserial  and  in  simple  series 
near  the  apex,  in  arcs  of  from  four  to  seven  pairs  near  the  larger  tubercles, 
crowded  and  polyserial  actinally.     lAmb  with  two  vertical  rows  of  primary 


Äcrocidaris  nobilis  Ag.     Upper  Jura  ;  St.  Sulpice,  near  Locle,  Neuchätel.     .1,  Dorsal  view,  B,  Ventral  view. 
C,  Spina,  i/i.     D,  Three  Compound  Amb  plates,  enlarged. 


tubercles  ;    only  the  largest  are  perforate  and  crenulate.      Spines  cyclindrical, 

often  tricarinate.     Upper  Jura  and  Cretaceous. 

Goniopygus  Agassiz.  Apical  disk  large,  plates  more  or  less  ornamented ; 
oculars  insert,  genital  plates  punctured  on  adoral  margin. 
Peristome  very  large,  with  small  branchial  incisions. 
Cretaceous  and  Eocene. 

Glypticus  Ag.  (Fig.  387).  Amb  straight,  and  narrow 
except  at  the  peristome,  where  the  poriferous  areas  are 
expanded  ;  with  two  vertical  rows  of  small,  smooth,  primary 
tubercles.  lAmb  tubercles  replaced  abactinally  by  warty 
or  irregulär  elongate  elevations.  Epistroma  much  developed. 
Abundant  in  Upper  Jura. 


Fia  387. 


Family  2.     Aspidodiadematidae  Duncan. 


Glypticus  hieroglyph- 
ims  Goldf.  Coral  Rag 
(Glyptician) ;  Fringeli, 
Switzerland.     l/i- 


Ambulacral  plates  simple.     Coronal  plates  thin,  not  imbri- 
cating.    Base  of  Corona  resorbed.     Oculars  all  exsert,  or  all  may 
be   insert.      Peristome   with   ten   large  primordial    ambulacral 
Lantern  erect.     Lias  to  Kecent. 

Orthopsis  Cotteau.  Amb  much  narrower  than  the  lAmb,  straight,  and  with 
numerous  pairs  of  pores  in  straight  series.  Amb  with  two,  lAmb  with  several 
vertical  rows  of  small,  piain,  perforate  tubercles.     Jura  and  Cretaceous. 

Eodiadema  BuncB^n.  Lias;  England.  E chinopsis  Ag.  Eocene  ;  Europe  and 
Egypt.     Aspidodiadema  A.  Ag.    Apical  disk  very  large,  oculars  insert.    Recent. 


Family  3.     Oentrechinidae  Jackson  (IJiadematidae  Peters). 

Ambulacral  plates  Compound.  Coronal  plates  not  imbricate  (Mesozoic),  or  more 
or  less  imbricate  {Recent).  Base  of  corona  resorbed.  Oculars  exsert,  or  one  to  all 
insert.      Periproct  more  or  less  plated,  to  nearly  leathery.      Peristome  with  ten 


CLASS  I 


ECHINOIDEA 


27' 


primordial  ambulacral,  also  non-amhulacral  plates.     Lantern 
indined.     Stewarts  organs  slight,  or  absent.     Lias  to  Recent. 

Centreehinus  Jackson  {Diadema  Schynvoet)  (Fig.  368, 
narrow,  often  projecting;  two vertical 
rows  of  small,  primary,  crenulate  and 
perforate  tubercles  extending  from 
peristome  to  apex.  IAr)ih  with  two 
or  more  vertical  rows  of  primary 
tubercles  resembling  those  of  the 
Amb,  but  larger.  Secondary  tubercles 
and  granules  surrounding  the  scrobi- 
cules.  Spines  long,  hollow,  longitu- 
dinally  striated.     Lias  to  Recent. 

Hemipedina  AVright.  Jura,  Creta- 
ceous  and  Recent.  Differs  from  Centre- 
ehinus in  having  simple  Amb  plates 
near  the  apex,  and  perforate,  but 
not  crenulate  tubercles. 

Pseudodiadema  Desor  (Fig.  388). 
Includes  small  species  having  wide 
Amb,  tubercles  of  uniform  size  in 
Amb  and  lAmb  areas,  and  oculars 
typically  all  exsert.  Jura  to  Ter- 
tiary. 

Heterodiadema      Cotteau.       Like 
Centreehinus,    but    with    the    apical 
System  greatly  extended  into  the    depressed  posterior 
H.  libycum  Cotteau. 


erect,  or  (Astropijga) 
D).     The  Amh  are 


Pseudodiaclenm  neglectum 
Jura.  A,  B,  Profile  and 
C,  Ambulacrum,  enlarged.' 


Thurm.  Froin  the  Bernese 
ventral  aspect  of  test,  Vi- 
D,  Spine,  V-i- 

lAmb.      Cretaceous. 


Codiopsis  Ag.  (Fig.  389).     Primary  tubercles  of  both  areas  small,  smooth. 


Fig.  389. 

Codiopsis  dovia  (Desin.).     Cenonianian  (Tourtia)  ;  Tournay,  Belgium.     A,  Sirle-view  of  test,  Vi-     -R,  Ventral 

aspect  of  sanie.     C,  Apical  systein,  enlarged. 

nearly  equal  in  size,  and  only  occurring  actinally  and  for  a  short  distance 
toward  the  ambitus.     Pore-pairs  uniserial.     Cretaceous. 

Cottaldia  Desor.  Cretaceous  and  (?)  Recent.  Fleurodiadema  de  Loriol. 
Jura.     Magnosia  Michelin.     Jura  and  Cretaceous. 

Diplopodia  M'Coy.  Amb  narrow,  with  two  vertical  rows  of  perforate  and 
crenulate  primary  tubercles.  Pore-pairs  in  double  vertical  series  near  the 
])oles,  uniserial  at  the  ambitus.     Jura  and  Cretaceous. 

Fedinopsis  Cotteau.     Cretaceous.      Phi/mechinus  Desor.     Jura. 


278 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


Pedina  Ag.  Amh  narrow,  poriferous  areas  wide.  Both  areas  with  two 
vertical  rows  of  small,  perforate,  primary  tubercles.     Upper  Jura. 

Pseudopedina  Cotteau.  Like  the  preceding,  but  with  larger  primary 
tubercles,  which  are  present  in  the  Ämb  near  the  ambitus  only.     Upper  Jura. 

Micropedina  Cotteau.  Amb  with  several,  and  lAmb  with  numerous  vertical 
rows  of  very  small  primary  tubercles.     Cretaceous. 

Leiopedina  Cotteau  (Chrysomelon  Laube).  Test  large,  melon-shaped.  Amb 
long,  straight,  very  broad.  Poriferous  areas  broad,  pore-pairs  triserial,  and 
almost  horizontal.  Plates  very  numerous,  low,  broad,  Compound.  Tubercles 
small,  piain,  finely  perforate,  in  two  distant  vertical  rows.     lAmh  broad,  with 


Pio.  390.. 

Stomechinus  lineatus  (Goldf.).     Coral  Rag;  Sontheim,  Würtemberg.     A,  Side-view  of  test,  i/j.     B,  Portion 

of  Retinal  surface. 

two  rows  of  tubercles  similar  to  the  ambulacral,  and  with  intermediate 
granules.     Eocene. 

Stomechinus  Desor  (Fig.  390).  Distinguished  from  Pedina  by  its  wider 
Amb,  and  imperforate,  non  -  crenulate  primary  tubercles.  Secondary 
tubercles  and  granules  often  present.     Jura  and  Cretaceous. 

Codechinns  Desor.  Tubercles  very  small,  piain,  irregularly  distributed. 
Cretaceous. 

Polycyplms  Agassiz.     Jura.     Astropyga  Gray.     Recent. 


Family  4.     Echinothuriidae  Wyville  Thomson. 

Ambulacral  plates  Compound.  Coronal  plates  very  thin,  imbricate.  Primordial 
interambulacral  plates  in  basicoronal  row.  Base  of  Corona  not  resorbed.  Oculars 
insert,  often  separated  from  the  genitals  by  interspaces.  Genitals  more  or  less  split 
by  secondary  sutures.  Periproct  leathery  but  partially  plated.  Peristome  with  many 
rows  of  ambulacral  plates  only.  Lantern  inclined.  Radial  peristomal  and  somatic 
muscles.     Stewarts  organs  present.     Jurassic  to  Recent. 

This  family  is  represented  by  several  living  and  two  extinct  genera,  the 
latter  being  known  only  by  fragmentary  specimens.  Pelanechinus  Keeping 
is  found  in  the  Upper  Jura,  and  Echinothuria  Wood  ward  in  the  Upper 
Cretaceous  of  England.  Phormosoma  Wyv.  Thomson  (Fig.  371,  A)  and 
Asthenosoma  Grube.     Recent,  occurring  chiefly  in  depths  below  1 00  fathoms. 


CLASS  I  ECHINOIDEA  279 

Suborder  B.     STIRODONTA  Jackson. 

Teetli  keeled.  Epiplujses  narrow,  not  meeting  in  suture  over  the  foramen 
magniim.  Amhulacral  plates  Compound  or  largely  simple.  Coronal  plates  not 
imbricate.  Primordial  interambulacral  plates  resorhed  or  retained  in  the  basicoronal 
row.  Base  of  corona  resorbed  or  not.  Oculars  all  exsert  or  becoming  insert  in  the 
sequence  I,  V,  or  V,  I,  IF,  II,  III.  Periproct  with  prominent  suranal,  o?'  mth 
many  small  plates,  or  foiir,  or  five  large  plates  only.  Peristome  with  ten  primordial 
ambulacral,  also  non-ambulacral  plates.  Lantern  erect.  Primary  tuber  des 
imperforate,  or  exceptionally  perforate.     Jurassic  to  Recent. 

Family  1.     Saleniidae    Desor. 

Ambulacral  plates  Compound,  or  largely  simple.  Primordial  interambulacral 
plates  resorbed,  Base  of  corona  resorbed.  Oculars  exsert  or  becoming  insert  in  the 
sequence  I,  V,  IV,  II,  III.  Periproct  with  a  permanent  large  suranal,  or  more 
large  plates,  with  small  anal  plates.  Primary  tubercles  imperfm^ate,  or  perforate. 
No  spurs  from  pyramids  supporting  teeth  dorsally.     Jura  to  Recent. 

Peltastes  Ag.  (Fig.  391).     Amb  straight  or  slightly  flexuous,  with  simple 


Fig.  391. 

Peltastes,  apical  System  ;  

m,  madreporite.  ^  '^IBSSF^  Fio  392 

Salenia  fcutigera  Gray.  White  Clialk ;  Charente 
(after  Cotteau).  A,  Lateral  and  dorsal  aspects  of 
tests,  Vi-     ^>  Apical  System,  enlarged. 

plates  abactinally  and  with  small  primary  tubercles  near  the  poriferous 
areas.  lAmb  broad,  with  large,  imperforate  primary  tubercles,  diminishing 
in  size  toward  the  poles.  The  suranal  plate  is  small,  in  contact  with  the 
lateral  genitals,  but  not  touching  the  posterior  one.  Upper  Jura  and 
Cretaceous. 

Salenia  Gray  (Fig.  392).  Test  small,  globose,  or  depressed.  Amb  plates 
Compound  or  largely  simple.  The  suranal  plate  is  in  contact  with  all  the 
genitals ;  oculars  all  exsert  or  ocular  I  reaching  the  periproct,  perforated  at 
the  adoral  edge.     Cretaceous  to  Recent. 

Goniophorus  Agassiz.  Upper  Greensand ;  Europe.  Heterosalenia 
Cotteau.     Cretaceous  ;  Europe. 

Acrosalenia  Ag.  (Figs.  368,  C;  393).  Test  depressed.  Amb  plates  simple 
primaries  near  the  apical  system,  Compound  near  the  ambitus  and  actinally. 
lAmb  tubercles  large,  perforate,  and  crenulate  ;  those  of  the  Arnb  much  smaller, 
and  in  two  vertical  rows.  Periproct  large,  bounded  anteriorly  by  the  suranal 
plate,  which   is   in   contact   with   the   four   large   anterior  genitals,   or   more 


280  ECHINODERMATA— ECHINOZOA  phylum  iv 

than    one   large   periproctal   plate.     Oculars  all  .exsert  or  one  to  all  insert, 


Acrosalenia  hemicidaroides  Wright.     Middle  Jura  ;  Stanton,  Wiltshii 

of  test,  Vi  (fifter  Wright). 


Dorsal,  lateral  and  ventral  aspeets 


commonly  I,  Y  insert.      Spines  cylindrical,  striated   or  piain.       Represented 
by  numerous  species  from  the  Lias  to  the  Lower  Cretaceous. 


Family  2.     Phymosomatidae  Meissner. 

Ämbulacral  plates  Compound.  Primordial  interambulacral  plates  resorbed. 
Oculars  becoming  insert  in  the  sequence  I,  F,  IV,  II,  III.  Periproct  with 
numerous  small  plates  only.  Primary  tubercles  imperforate.  Spurs  from  pyramids 
Support  the  teeth  dorsally.     Jura  to  Recent. 


Cyphosoma  Agassi z  (Fig.  394). 


Fig.  394. 

Cyphosoma  hoeniui  Mantell.     White  Chalk 
Sussex.     Ventral  aspect,  '/i- 


Test  depressed,  with  few  coronal  plates. 
Amb  with  well-developed  poriferous  areas 
undulating.  Pore-pairs  biserial  at  the 
apex,  crowded  at  the  peristome.  lAmb 
broader  than  the  Amb,  with  two  or  more 
vertical  rows  of  primary  tubercles,  which 
are  imperforate  and  crenulate,  like  those 
of  the  Amb.  Apical  systcm  encroaching 
upon  the  posterior  lAmb.  Jura  to  Ter- 
tiary. 

Glyptocidaris  A.  Agassiz.  Recent.  This 
genus  shows  the  character  of  pyramidal 
spurs  given  as  a  family  character. 

Micropsis  Cotteau.  Amh  with  three  to 
five  elements  to  a  Compound  plate,  and 
two  or  more  vertical  rows  of  small  primary 
tubercles,  which  are  perforate  and  crenu- 
late.    Cretaceous  and  Eocene. 


Family  3.     Stomopneustidae   Mortensen. 

Ambidacral  plates  Compound,  composed  of  three  elements  each,  at  the  mid-zone 
every  four  or  five  ämbulacral  plates  are  boand  together  and  grown  over  by  one 
primary  tubercle.  Primordial  interambulacral  plates  and  base  of  corona  resorbed. 
Oculars  becoming  insert  in  the  sequence  1,  V,  IV.  Periproct  with  many  small  plates 
only.  Primary  tubercles  imperforate.  Spurs  from  pyramids  support  the  teeth 
dorsally. 


CLASS  I 


ECHINOIDEA 


281 


Stomopneustes  Ag.  Am,h  straight,  with  pores  in  arcs  of  three  pairs  dorsally 
crowded  and  triserial  below  the  ambitiis.  Both  aieas  with  two  vertical  rows 
of  piain  tubercles.  Formerly  classed  with  the  Echinometridae,  from  which  it 
diifers  radically,  especially  in  structure  of  the  lantern.     Tertiary  and  Recent. 


Family  4.     Arbaciidae  Gray. 


Ambulacral  plates  Compound, 
coronal  row.     Base  of  Corona  not 


Primordial  interambulacral  plates  in  the  basi- 
resorhed.     Oculars  all  exsert  or  becoming  insert 


IV.     Periproct  with  four  or  five  large  plates  only. 
No  spurs  from  pyramids  supporting  teeth  dorsally. 


Primary 
Tertiary 


With  three  elements  in  an  ambulacral  plate.     Tertiary 


Recent. 


in  the  sequence  V,  I, 
tubercles  imperforate. 
to  Kecent. 

Arbacia  Gray, 
and  Recent. 

Tetrapygiis  Agassiz.      With  five  elements  in  an  ambulacral  plate 

Coelopleurus  Ag.  (Fig.  395).  Amb  with  two  vertical 
rows  of  piain,  primary  tubercles  placed  on  flat  scrobi- 
cules,  diminishing  in  size  toward  the  apex,  and  some- 
times  replaced  there  by  granules.  lAmb  with  a  large 
bare  median  area  abactinally  ;  the  tubercles  largest  at 
the  ambitus,  sometimes  disappearing  toward  the  apical 
System.     Tertiary  and  Recent. 

Podocidaris  A.  Agassiz.  Recent ;  Caribbean  Sea  and 
Philippines. 

Suborder  C.     CAMARODONTA  Jackson. 

Teeth  keeled.  Epiphyses  wide,  meeting  in  suture  over 
the  foramen  magnum.  Ambulacral  plates  Compound.  Coronal 
plates  not  imbricate.  The  ambitus  is  circular,  or  elliptical 
through  a  sidewise  axis.  Primordial  interambulacral  plates 
resorbed.       Base  of  Corona  resorbed.     Oculars  all  exsert  or 

becoming  insert  in  the  sequence  V,  I  or  I,  F,  IF,  II,  III.  Periproct  usnally  plated 
with  many  small  plates  {in  one  genus,  Parasalenia,  with  four  large  plates). 
Peristome  with  ten  {in  one  species  five)  primordial  ambulacral  plates  and  rnore  or 
fewer  non-ambulacral  plates  ;  rarely  the  latter  are  absent.  Lantern  erect.  Primary 
tubercles  imperforate.     Cretaceous  to  Recent. 


Fig.  395. 

Coeloplewus  equis  Ag. 
Eocene ;  Biarritz,  France. 


Family  1.     Eohinidae  Agassiz. 

Ambitus  circular.  A^o  pits  or  sculpturing  in  the  coronal  plates  dorsally. 
Ambulacral  plates  at  mid-zone  composed  of  three  elements  each,  rarely  darsally  of 
two  elements.  Oculars  all  exsert,  or  becoming  insert  in  the  sequence  I,  F,  IF,  II, 
III.     Cretaceous  to  Recent. 

Echinus  Linn.  Amb  straight,  with  narrow  poriferous  zones ;  pore-pairs  in 
more  or  less  vertical  arcs  of  triplets.  Interporiferous  areas  with  two  vertical 
rows  of  small,  piain,  primary  tubercles  with  or  without  irregularly  placed 
secondary  tubercles  and  primaries.  lAmb  with  two  vertical  rows  of  primaries, 
and  few  or  numerous  rows  of  secondary  tubercles  and  miliaries.  Peristome 
small,  circular.     Cretaceous  to  Recent. 


282  ECHINODEEMATA— ECHINOZOA  phylum  iv 

Stirechinus  Desor.  Both  areas  with  two  rows  of  large,  piain,  primary 
tubercles  situated  on  raised  keel-like  projections.     Pliocene ;  Europe. 

Glyptechinus  de  Loriol.  Cretaceous.  Tripneustes  Agassiz.  Miocene  and 
Recent. 

Hypechinus  Desor.  Tertiary.  Toxopneustes  Agassiz.  Recent.  Boletia 
Desor.     Recent. 

Family  2.     Temnopleuridae  Desor. 

AmUtus  circular.  Pits,  or  sculpturing  in  coronal  plates  dorsally.  Ambulacral 
plates  at  the  mid-zone  composed  of  three  elements  each.  Oculars  usually  all  exsert. 
Cretaceous  to  Recent. 

Glyphocyphus  Haime.  Test  small,  depressed  spheroidal.  Amb  narrow, 
straight,  with  two  vertical  rows  of  small,  perforate,  crenulate,  primary 
tubercles,  and  numerous  miliaries.  lAmb  broad,  with  two  rows  of  primaries 
somewhat  larger  than  those  of  the  Amb.  Transvörse  and  median  sutures 
grooved.     Oculars  all  insert.     Cretaceous  and  Eocene. 

Didyopleurus  Duncan  and  Sladen.  Eoncene ;  Asia,  Europe  and  Egypt. 
Paradoxechinus  Laube.  Miocene  ;  Australia.  Echinocyphus  Cotteau,  and  Zeuglo- 
pleurus  Gregory.     Cretaceous  ;  Europe. 

Temnopleiirus  Ag.  Trans verse  sutures  of  all  plates  grooved  and  pitted. 
Apical  System  small,  compact,  slightly  projecting.     Tertiary  and  Recent. 

Temnechinus  Forbes.  Test  small,  subglobose,  depressed  abactinally. 
Both  areas  with  two  vertical  rows  of  piain  primaries.  Apical  System 
prominent,  compact,  the  sutures  between  the  plates  more  or  less  grooved. 
Late  Tertiary  and  Recent. 

Salmacis  Ag.  Eocene,  Pliocene  and  Recent.  Älicrocyphus,  Amblypneustes, 
and  Holopneustes  Agassiz.      Recent. 

Family  3.     Strongylocentrotidae  Gregory. 

Ambitus  circular.     No  pits  or  sculpturing  in  the  coronal  plates.  Ambulacral 

plates  at  the  mid-zone  composed  of  from  four  to  ten  elements  each,  rarely  (some 

Echinostrephus)  of  three  elements  each.     Oculars  all  exsert  or  becoming  insert  in  the 
I,  F,  IF,  II.     Tertiary  to  Recent. 

Strongylocentrotus    Brandt    (Figs.    371,   E ;    372-3, 

396).   Test  symmetrical  and  polyporous.   ^m&  straight, 

broad  at  the  ambitus  and  peristome,  and  with  broad 

poriferous  areas.     Pore-pairs  in  oblique  arcs  or  almost 

transverse  series  of  from  four  to  ten  pairs,  and  crowded 

actinally.      Interporiferous    areas    with    two    vertical 

Flu.  396.  rows  of  piain  imperforate  primary  tubercles;  secondaries 

strongylocentrotus     dröbach-  and  miliarics  also  present.     lAmb  with  two  rows  of 

po^^uM  Sm4iat?!'^^'''^"    ^''""   primary,  and    four    or    more  of    secondary  tubercles. 

Late  Tertiary  and  Recent. 

Sphaerechinus  Desor.     Amb  straight,  wide.     Pore-pairs  in  arcs  or  oblique 

lines  of  four  to  eight  pairs,  polyserial  actinally.     Interporiferous  areas  with 

two  to  six  vertical  rows  of  piain,  imperforate  primaries,  and  horizontal  rows 

of  secondary  tubercles  and  miliaries.     lAmb  with  two  to  twelve  vertical  rows 

of  primaries.     Pliocene  and  Recent. 

Eurypneustes  and  Aeolopneustes  Duncan  and  Sladen.     Eocene ;  Asia. 


CLASS  I  ECHINOIDEA  283 

Family  4.     Echinometridae    Gray. 

Ambitus  elliptical  in  a  sidewise  axis.  No  püs  or  sculpturing  in  coronal  plates 
'hrsalhj.  Ambulacral  plates  at  mid-zone  composed  of  four  or  more  elements  each, 
rarely  (Parasalenia)  of  three  elements  each.  Oculars  all  exsert,  or  becoming  insert 
in  the  sequence  V,  I,  IV.     Recent. 

Echinometra  Gray ;  Heterocentrotns  and  Colobocentrotus  Brandt ;  with  highly 
specialised  spines.     Recent. 

Order  4.     EXOCYCLOIDA   Jackson. 

Test  irregulär,  exocyclic,  periproct  outside  of  oculogenital  ring  in  interambulacrum 
-7.  Two  columns  of  plates  in  each  ambulacral  area  and  two  columns  of  plates  in 
each  interambulacral  area.  Regulär  in  form,  or  more  freguently  more  or  less 
markedly  bilaterally  symmetrical  through  the  axis  III,  5.  Slight  or  no  resorption 
of  base  of  Corona  by  the  advance  of  the  peristome,  Lantern  present  or  absent. 
Peristomal  gills,  or  ambulacral  gills  only.     Sphaeridia  present.     Jura  to  Recent. 

This  Order  includes  all  exocyclic  Echini  excepting  the  Paleozoic 
Echinocystoida.  The  order  shows  structural  characters  associating  it  with 
the  Arbaciidae. 

SuborderA.     HOLECTYPINA   Gregory. 

Ambulacral  plates  Compound,  or  largely  simple,  areas  not  petaloid  dorsally. 
Primordial  ambulacral  plates  unknown.  Primordial  interambulacral  plates  in  basi- 
coronal  row,  or  in  part  resorbed.  Base  of  Corona  slightly  resorbed.  Oculars  and 
genitals  all  present  and  distinct,  or  fused,  or  genital  5  absent ;  when  present  it  is 
imperforate.  Periproct  unknown.  Peristome  central,  structure  unknown.  Lantern 
inclined  so  far  as  known.  Teeth  keeled,  epiphyses  narrow.  Foramen  magnum 
moderately  deep.  Pyramids  with  ridges  on  lateral  wings.  Perignathic  girdle  con- 
sisting  of  apophyses  and  auricles,  or  auricles  only.  Peristomal  gills  present.  Jura 
to  Tertiary. 

Family  1.     Discoidiidae  Gregory. 

Perignathic  girdle  consisting  of  apophyses  and  auricles. 

Discoidea  Gray  (Fig.    397).     Test   hemispherical  above   the   margin,   flat 


Discoiiha  cylindrica  Agassiz.     Upper  Cretaceous  ;  Lüneburg.    A,  Side-view.     B,  Test  broken  open  to  show 

the  inner  partitions,  i/i. 

actinally.     Amb  narrow,   with  some  Compound  plates  near  the  ambitus  and 
a>ctinally ;    pore-pairs   very    numerous,    small.      lAmb    with    distinct    median 


284 


ECHINODERMATA— ECHINOZOA 


PHYLÜM  IV 


sutures,  and  small,  perforate  and  crenulate  tubercles.  Plates  within  the 
actinal  surface  with  radiating  ribs,  ten  in  all,  extending  as  far  as  the  peri- 
stome ;  appearing  on  casts  as  deep  depressions.  Periproct  small,  infra- 
marginal.    Cretaceous. 

Conuhis  Leske  (Galerites  Lam.).     Amh  flush  or  sligTitly  raised,  apetalous, 
straight ;  some  of  the  plates  Compound.     Peristome  sunken,  slightly  decagonal. 


Fio.  398. 
Conoclypeus  conoideus  (Goldf.).     Eoceiie  ;  Kresseiiberg,  Bavaria  (^^  natural  size). 

symmetrical.  Perignathic  girdle  indicated  by  a  thickening  of  the  lAmb  as  a 
low  false  ridge.     Abundant  in  the  Lower  and  Middle  Cretaceous. 

Lanieria  Duncan.     Cretaceous  or  Eocene  ;  Cuba. 

Conoclypeus  Ag.  (Figs.  369,  B ;  398).  Test  large,  thick  ;  conical  or  vaulted 
dorsally,  flat  actinally.  Amb  long,  open,  with  broad  poriferous  areas  nearly  to 
ambitus,  narrowing  thence  to  peristome.  Pores  wide  apart  and  in  pairs  where 
the  areas  are  broad  ;  the  pairs  separated  by  costae.  Pores  continued  in  single 
series  over  the  ambitus  as  far  as  the  central,  pentagonal  peristome.  Periproct 
infra-marginal,  oval  (?),     Cretaceous  and  Eocene ;  Europe. 


Family  2.     Pygasteridae  Gregory. 
Perignathic  girdle  ^pparently  consisting  of  aurides  only. 
Holeäypus  Desor  (Figs.  369,  B ;  399).     Ar)ih  narrow,  straight,   widest  at 


Fig.  399. 


A,B,  Holectypusorificatua^c\\\oi\\.     Upper  Jura  ;  Streitber<^,  Franconia.     (',  ]),  JL  depresmf:  (Jjeske).     Mlddh 
Jura  ;  France.     Apical  System  and  ventral  surface  (after  Cotteau). 


CLASS  I 


ECHINOIDEA 


285 


ambitus  ;  some  of  the  plates  Compound.  lAmb  with  rather  large  plates,  and 
many  rovvs  of  tubercles.  Peristome  large,  decagonal,  with  well-marked  branchial 
incisions,  jaws,  and  feeble  perignathic  girdle. 
Periproct  large,  pyriform,  situated  between  the 
peristome  and  posterior  edge  of  the  test.  Apical 
System  small,  central.     Jura  and  Cretaceous. 

Pileus  Desor.  Test  large,  sub-hemispherical 
dorsally,  flat  actinally.  Tubercles  small,  ir- 
regularly  arranged.  Periproct  supra- marginal, 
small,  broadly  ovoid.     Upper  Jura. 

Pi/r/aster  Ag.  (Fig.  400).  Test  large,  de- 
pressed  dorsally,  concave  actinally.  Amb  straight, 
similar,  flush  or  slightly  raised,  widest  at  the 
ambitus.  Poriferous  areas  straight,  simple, 
narrow ;  tubercles  of  interporiferous  areas  in 
two  or  four  vertical  rows ;  those  of  the  lAmh  in 
horizontal  rows.  Peristome  large,  decagonal, 
with  jaws  and  feeble  perignathic  girdle.  Peri- 
proct immediately  beyond  the  apical  System. 
Jura  and  Cretaceous. 

Galeropijgus  Cotteau;  Pachyclypeus  Desor. 
Upper  Jura ;  Europe. 


Fig.  400. 


Pyqaster  umhclla  Agassiz.  Oxfordian  ; 
Chätillon-snr-Seine.  Young  individual, 
Vi  (after  Cotteau). 


Suborder  B.     CLYPEASTRINA  Gregory. 

Ambulacral  plates  simple,  areas  petaloid  dorsally.  Ventrally  amhulacral  pores 
are  minute  and  specialised.  Primordial  ambulacral  plates  in  basicoronal  row. 
Primordial  interambulacral  plates  in  basicoronal  row,  or  exceptionally  (Arachnoides) 
pushed  dorsally  and  in  pari  resorbed  by  intracoronal  resorption.  Base  of  Corona  not 
resorbed.  Ocular  and  genital  plates  fused  in  a  mass,  usually  no  genital  pore  in  area 
5.  Genital  pores  within  the  fused  mass  or  outside  in  interambulacra  1,  2,  3,  Jf.. 
Periproct  plated.  Peristome  central,  leathery,  Lantern  procumbent,  highly  modified, 
teeth  keeled,  foramen  magnum  very  shallow,  small  epiphyses  and  braces,  but  no  com- 
passes.  Pyramids  usually  without  ridges  on  lateral  wings.  Perignathic  girdle  con- 
sisting  of  auricles  only,  on  ambulacral,  or  on  interambulacral  plates.  No  peristomal, 
but  ambulacral  gills  only.     Cretaceous  to  Recent. 


Family  1.     Olypeastridae  Agassiz. 

:■■  Test  small  to  very  large,  depressed,  flat  or  high.  Petaloid  parts  of  the  ambulacra 
highly  developed,  usually  unequal ;  the  actinal  furrows  straight.  Interambulacra 
actinally  discontinuous ;  one  peristomal  plate  in  each  area.  Perignathic  processes 
tall,  narrow,  two  on  each  ambulacrum,  fitting  in  below  the  large  jaws.  Peristome 
central,  pentagonal ;  periproct  small,  marginal  or  infra-marginal.  Internal  structure 
with  needles,  pillars,  and  other  processes  extending  fromfloor  to  roof,  especially  near 
the  edge  of  the  test ;  sometimes  these  are  fused  to  form  concentric  partitions,  and  the 
ambulacra  may  also  be  protected  by  an  inner  wall.     Tertiary  and  Recent. 

Clypeaster  L3.m.  (Figs.  369,  F;  374,  401,  402).    Actinal  surface  flat,  with  the 
peristome  deeply  sunken  ;  edge  thin,  undulating  in  contour,  with  or  without 


286 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


re-entering  angles.     Petals  long,   broad,   tumid ;   pores  wide   apart,   unequal, 
conjugated.     Periproct  near  or  at  the  edge.     Internal  structure  not  forming 

a  double  wall  covering  the 
Amb.  This  genus  includes 
some  of  the  largest  known 
Echinoids.  Eecent  species 
are  littoral,  or  shallow- 
water  inhabitants.  Tertiary 
and  Recent. 

Anomalanthus  Bell.     Re- 

>if^        Cent.     Laganum  Gray.     Be- 

longs  properly  to  a  separate 

rj'l         family  or  subfamily.     Ter- 

'^*''  tiary  and  Recent. 

Family  2.     Pibulariidae 
Gray. 

Flu.  401. 


Clypeaster  cbegypticus  Mich.     Pliocene  ;  Gizeh,  near  Cairo.     Fragment 
showing  internal  calcareous  deposlts.     au,  Auricles. 


Test  small,  with  rudi- 
mmtary,  widely  open,  few- 
pored  petals.  Interambulacra 
small,  with  a  single  apical  and  a  single  peristomal  plate.  Jmhulacra  limited 
adinally  on  the  interior  of  the  test  hy  low  vertical  partitions  at  their  sides,  radiating 


Fig.  402. 
c?'  grandifiorus  Bronn.     Miocene  ;  Boutonnet,  near  Montpellier,     i/o  natural  size  (after  Desor). 

toward    the  peristome.     Perignathic  processes    broad,   low,    situated   on   each  inter- 
ambulacrum.     Periproct  usually  actinal.     Cretaceous  to  Recent. 

Echinocyamus  Leske  (Fig.  403).     Test  thick,  depressed,  pyriform  or  sub- 
circular  in  outline,  concave   actinally.      Amb  broader  than  the  lAmb,  short 


CLASS  I 


ECHINOIDEA 


287 


where  slightly  petaloid,  widely  open  distally  :  pore-pairs  few  and  iiicreasingly 
far  apart.      Peristome   central,  pentagonal,  with  small 
jaws.      Periproct  between  the  peristome  and  posterior 
edge  of  the  test.     Cretaceous  to  Recent. 

Subgenus  Scutellina  Ag.     Periproct  small,   marginal  or  more 
or  less  supra-  or  infra-marginal.     Tertiary.  „ 

Sismondia   Desor.      Test   sub -pentagonal    or    ovoid,     Echinoeyamus  piuccutus 
depressed,  inflated  at  the   margin.      Petaloid   parts  of  mocei  •%ciiy'''y^  ^^'^' 
the  Jmh  usually  long,   more  or  less  open  ;  pore-pairs 
not  continued    actinally.     Tubercles    minute.     Eocene 
and  Miocene. 

Fibularia  Lam.  (Fig.  404).  Test  thin,  ovoid,  tumid 
dorsally  and  at  the  side.  ^mb  short ;  pore-pairs  very 
few,  continued  wide  apart  to  *  the  margin,  non-con- 
jugated.  Peristome  and  periproct  small,  sunken,  close 
together.     Upper  Cretaceous  and  Recent. 

Buna  Ag.     Tertiary  ;  Europe. 


Fig.  404. 

Fibularia  suhglobosa  (Goldf. ). 
Upper  Cretaceous ;  Maest- 
richt,  Belgium.     i/j. 


Family  3.      Scutellidae  Agassiz. 

Test  very  flat,  with  entire  or  incised  margin ;    limules  or  slits  in  the  areas  or 
not.     Ambulacral  furrows  bifurcating  and  branching.     Peristome  flush  ;   jaws  flat, 


Fi(i.  405. 
Scutella  auhrotundata  Lam.     Miocene  ;  Bordeaux.     .4,  B,  Ventral  and  dorsal  aspects  ;  r,  Öectioii,  Vi- 

teeth  superior.     Eadiating  partitions  between  the  floors  internally.       Tertiary  and 
Recent. 

Scutella  Lam.  (Fig.  405).      Test  circular  or  sub-circular  in  outline,   some- 
times  undulating  or  notched,  broadest  behind.     Petaloid  parts  of  the  Amb 


288  ECHINODERMATA— ECHINOZOA  phylum  iv 

uneqiial,  well-developed,  nearly  closed.  Peristome  small,  central,  sub-circular. 
Periproct  very  small,  infra-marginal.  Apical  System  central,  more  or  less 
pentagonal.     Tertiary. 

Subgenus  Ediinarachnius  Leske  {Dendraster  Ag.).  Apical  system  eccentric  in  front  or 
behind.     Periproct  actinal  or  marginal.     Recent. 

Echinodiscus  Leske.  Like  Scutella,  but  truncated  posteriorly,  and  with  two 
round  or  «longate  lunules  or  slits,  one  in  each  of  the  median  lines  of  the 
postero-lateral  Amh.     Tertiary  and  Eecent. 

Encope  Ag.  Test  with  a  broad  notch  or  a  lunule  in  the  median  line  of 
each  Amb,  and  a  lunule  in  the  posterior  lAmh.     Miocene  and  Recent. 

Mellita  Agassiz.  Test  very  tlat,  with  five  or  six  usually  closed  lunules, 
more  rarely  cuts ;  one  in  the  median  line  of  the  posterior  lAmb,  the  others 
in  the  Amb.  Amb  petaloid  dorsally,  the  post^erior  pair  the  longest.  Pliocene 
and  Recent. 

Lenita  Desor.  Eocene.  Ilotula  Ag.  (Fig.  366,  g).  Recent.  Arachnoides 
Leske.    Pliocene  and  Recent. 

Suborder  C.     SPATANGINA  Jackson. 

Ambulacral  plates  simple,  areas  commonly  petaloid  dorsally  ;  in  some  types  pores 
are  absent  in  pari  of  the  plates.  Ambulacrum  III  often  differs  markedly  in  charader 
from  other  areas.  Ambulacral  plates  often  highly  specialised  in  form  and  size. 
Primordial  ambulacral  plates  in  the  basicoronal  row,  or  (Fourtalesia)  in  part  pushed 
dorsally.  The  basicoronal  plates  la,  IIa,  Illb,  IVa,  Vb,  are  larger  and  with  two 
pairs  of  pores  or  two  separate  single  pores,  whereas  the  Ib,  IIb,  Illa,  IVb,  Va  are 
smaller  with  one  pore-pair  or  one  single  pore.  Primordial  interambulacral  plates  in 
the  basicoronal  row  or  (Lovenia,  Pourtalesia)  pushed  dorsally.  Base  of  Corona  not 
resorbed.  Oculars  and  genitals  separate,  or  genitals  partially  fused.  Oculars 
apparently  absent  in  some  Pourtalesias.  Genital  5  absent,  and  some  additional 
genitals  rarely  absent.  Periproct  plated.  Peristome  eccentric,  plated  with  non- 
ambulacral  plates  only.  Lantern  and  perignathic  girdle  absent  (present  in  the  young 
of  Echinoneus,  A.  Agassiz,  1909).     No  peristomal,  but  ambulacral  gills  only. 

Tribe  A.     CASSIDULOIDEA   Duncan. 

Ambulacra  abactinally  petaloid  or  sub-petaloid,  usually  similar.  Some  or  all 
of  the  interambulacra  with  a  single  peristomal  plafe ;  the  postero-lateral  areas 
symmetrical  actinally,  without  any  fusion  of  plates;  no  plastrons.  Peristome 
variously  shaped,  with  or  without  floscelles. 

Family  1.      Bchinoneidae    Wright. 

Test  toll,  or  low  and  tumid  dorsally ;  turaid  and  rarely  fiat  actinally.  Apical 
System  central,  compact,  with  four  perforated  genitals.  Ambulacra  similar,  dorsally 
apetalous  or  sub-petaloid.  Pores  in  simple  pairs  or  in  oblique  triplets  actinally  ;  no 
floscelle.  Peristome  oblique  or  transversely  elliptical,  rarely  symmetrical.  Periproct 
actinal,  marginal  or  supra-marginal.     Cretaceous  to  Recent. 

•   Subfamily  A.      Echinoneinae    Desor. 

Test  low,  tumid,  and  more  or  less  pulvinate  actinally  ;  peristome  central  or  sub- 
central and  oblique. 


CLASS  I 


ECHINOIDEA 


289 


Echinoneus  Leske.     Amh  narrow,  actinally  uiiequally  broad,  owing  to  the 
obliquity  of  the  large,  triangulär  peristome.     Miocene  to  Recerit. 
Caratomus  Ag.     Cretaceous.     Amhlypygus  Ag.     Tertiary. 
Pyijaulus    Ag.    (Fig.    406).       Test    small,   thick ;    apical   System    slightly 


Fk;.  406, 


Pyriaulus  desmoulinsi  Ag.     Urgonian 
(Sclirattenkalk) ;  Säntis,  Switzerland.     i/i. 


Fig.  407. 

Pyr ina  inscia  (Ag.).     Neoconiian  (Hils)  ;  Berklingen, 

Brunswick.     Vi- 


Amh  narrow,  widest  at  the  ambitus ;  pore-pairs  in  simple 
the  pores  of  a  pair  sometimes  differently  shaped.     Cre- 


eccentric  in  front, 
series,  conjugated 
taceous. 

Pyrina  Desm.  (Fig.  407).     Like  the  preceding,  but  pores  non-conjugated, 
and  the  pairs  separated  by  costae.     Cretaceous  and  Eocene. 


Subfamily  B.     Echinobrissinae    Duncan. 

Test  depressed,  elongate,  tumid.  Ambulacra  sub-petaloid.  Apical  System  and 
peristome  eccentric ;  floscelle  ahsent  or  rudimentary.  Interamhulacra  entering  the 
peristomal  margin  witli  a  single  plate.     Periproct  supra-marginal. 

Nudeolites  Lam.  (Echinobrissus  Breyn.)  (Fig.  408).  Test  ovate,  rounded  in 
front,  broadest  and  more  or  less  truncated  behind;   or  rectangular,  with  the 


Fig.  40d 

A,  B,  Nudeolites  dunieularis  (Llhwyd).  Cornbrash ;  Egg,  Aargau.  Vi-  C,  D,  N.  scutatus  (Lam.).  Upper 
Oxfordian ;  Trouville,  Cahados.  C,  Ventral  aspect  of  large  individual.  D,  Apical  systeni,  enlarged  (after 
Cotteau). 

angles  rounded ;  or  sub-circular ;  concave  actinally.  Amb  unequal,  open  at 
the  end  of  the  sub-petaloid  parts  ;  pore-pairs  in  simple  series,  more  or  less 
unequal  in  shape  and  size,  the  outer  ones  elongate ;  below  the  sub-petaloid 
parts  the  pores  are  in  small  oblique  pairs,  conjugate  or  not.  Periproct  at 
Upper  end  of  a  groove  situated  on  the  abactinal  area  of  the  test.  Abundant 
in  Upper  Jura  and  Cretaceous ;  present  also  in  Eocene  and  late  Tertiary. 
VOL.  I  U 


290 


ECHINODERMATA—ECHINOZOA 


PHYLUM  IV 


üuhgenus  Bochmostoma  Duncsin  {Trematopygus  d'Orb.).     Like  the  preceding,  but  with 
oblique  peristome.     Cretaceous  ;  Europe  and  Nortli  America. 

Botriopygus  d'Orb.     Cretaceous.     Ilariona  Dames.     Eocene. 


Family  2.     Cassidulidae  Agassiz. 

Test  variable  in  shape.  Ämhulacra  petaloid,  sub-petaloid  or  apetalous  dorsally, 
and  with  crowded  doubling  of  the  pairs  of  pores  dose  to  the  peristomal  margin, 
forming  with  the  single,  swollen  and  ornamented  interamhulacral  peristomal  plates  a 
floscelle.     Jura  to  Recent. 

Test  small,  oblong,  depressed,  convex 
dorsally,  flat  actinally.  Amh  narrow, 
sub-petaloid,  not  closing  ;  pores  con- 
tinued  from  the  middle  part  to  the 
well-developed  floscelle.  Peristome 
eccentric  in  front ;  periproct  supra- 
marginal, longitudinally  elongated. 
Cretaceous  and  Eocene. 

Subgenus  Rhyncopygus  d'Orb.  Periproct 
transversely  eloiigate,  with  overhanging 
rostrum.     Cretaceous  to  Recent. 

Subgenus  Pygorhynchus  Ag.  Test  con- 
cave  actinally,  with  long  petals.  Peris- 
tome and  periproct  longest  transversely. 
Cretaceous  to  Miocene. 


Cassididus    Lam.    (Fig.    409). 


Fig.  409. 

Cassidulus  lapis-cancri  Lam.    A,  Test  in  three  positions. 
B,  Floscelle,  enlarged. 


Stigmatopygus  d'Orb.  Cretaceous.  Eurhodia  d'Arch.  and  Haime.  Eocene. 
Paralampas  and  Neocatopygus  Duncan  and  Sladen.  Eocene.  Catopygus  Ag. 
Cretaceous.  Studeria  Duncan.  Tertiary  and  Recent.  Phyllohrissus  Cotteau. 
Jura  and  Cretaceous. 

Clypeus  Agassiz.  Test  large,  low,  nearly  flat  actinally.  Amb  wide, 
petaloid,  not  closing   dorsally,  narrow  at   the  ambitus  and  actinally.     Pore- 


Pygurus  royerianus  Cotteau.     Klinmeridgian  ;  Tönnjesberg,  near  Hanover.    A,  B,  Dorsal  and  ventral  views 
of  test,  3/4  natural  size.     C,  Apical  System,  enlarged.    D,  Ambulacral  plates,  magnified. 


pairs  in  the  petaloid  parts  with  the  inner  pore  small  and  circular,  the  outer 


CLASÖ  I 


ECHINOIDEA 


291 


transversely  elongate,  and  in  a  long  groove.     Periproct  high  up,  usually  in  a 
groove  along  the  median  line  of  the  posterior  lAmb.     Upper  Jura. 

Pygurus  Ag.   (Fig.   410).       Test  large,  angular,  rounded  or  cordiform  in 
marginal  contour ;    depressed  or  rather  tall   and  sub-conical  dorsally.      Amh 


Fig.  411. 
Echinolampas  kleini  Goldf.     Oligocene ;  Doberg,  near  Bünde,     i/i. 

flush  dorsally,  unequal,  wide ;  the  petaloid  parts  contracting  but  not  closing 
marginally,  and  expanding  again  actinally,  where  the  Amb  are  grooved.  Peri- 
proct infra-marginal,  pyriform  or  ovoid,  in  a  special  area,  or  rostrum,  close  to 
the  posterior  edge  of  the  test.     Upper  Jura  and  Cretaceous. 

JEchinolampas  Gray  (Fig.  411).  Test  variable  in  size  and  shape,  more 
or  less  ovoid  or  circular  at  the  tumid 
marginal  outline;  tall  and  conical  or 
depressed  dorsally.  Amb  petaloid  for 
a  variable  distance;  pores  of  the  petals 
difFering  in  shape,  conjugated  and  con- 
tinued  beyond  in  simple  series.  Peri- 
stome  slightly  in  front,  or  sometimes 
central.  Periproct  transversely  ellip- 
tical,  infra-marginal.  Widespread  in 
Tertiary  and  Recent. 

Conolampas  and  Neolampas  A.  Ag. 
Recent.  Plesiolampas  Duncan  and 
Sladen.  Eocene.  Palaeolampas  Bell. 
•Upper  Cretaceous  to  Recent. 

Family  3.     Oollyritidae  d'Orbigny 
{Dysasterinae  Gray). 

Apical  System  disconneäed,  either 
elongate  or  sub- compact.  Ambulacra 
similar ;  bivium  widely  separated  from  fio.  4i2. 

the     trivium;     ßoSCelle    absent.       Jura    to        Cü%rite5  e^^ii>^ica  pesm     CaUovian ;  Mamers,  Sarthe. 
-*    •'  A,  B,  Test  in  proüle  and  froui  above,  Vi-     C'»  Apical 

Cretaceous.  system,  enlarged. 


292 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


CoUyrites  Desm.  (Fig.  412).  Test  ovoid,  tumid,  more  or  less  truncated 
posteriorly.  Amh  disjunct,  the  anterior  one  soraetimes  in  a  slight  groove. 
Width  of  the  Amh  increasing  towards  the  ambitus ;  pore-pairs  in  low  primary 
plates.  Periproct  posterior,  supra-marginal,  placed  in  a  groove.  Apical 
System  elongate,  separated  by  numerous  small  plates  belonging  to  the 
postero-lateral  lAmb.  Yery  abundant  in  the  Middle  and  Upper  Jura  and 
Cretaceous. 

Dysaster  Ag.  Differs  from  CoUyrites  in  details  of  the  apical  systeni,  the 
genitals  not  being  separated  by  the  antero-lateral  ocular  plates.  Upper  Jura 
and  Lower  Cretaceous. 

Hyhodypeus  Agassiz  (Fig.  413).  Jura.  Infradypeus  Gauthier.  Upper 
Cretaceous.     Grasia  Mich.     Jura. 


Fig.  413. 


Hyboclypeus  gibberulus  Ag,     Middle  Jura ;  Soleure,  Switzerland.    A,  B,  Dorsal  and  ventral  views. 
C,  Profile.     D,  Apical  System,  enlarged. 

Metaporhinus  Mich.  Test  very  tall,  slightly  longer  than  broad,  sub-cordi- 
form,  projecting  upwards  anteriorly,  grooved  and  oblique  behind.  Anterior 
Amb  in  a  groove,  with  small,  simple,  distant  pairs  of  pores  ;  the  other  Amb 
flexuous,  with  comma-shaped  pores  placed  obliquely  to  one  another.  Periproct 
supra-marginal.     Upper  Jura  and  Lower  Cretaceous. 


Tribe  B.     SPATANGOIDEA   Duncan. 

Peristome  eccentric  in  front,  rarely  pentagonal  in  the  adult,  usually  with  a 
labrum,  behind  which  is  a  long  plasfron  bounded  laterally  by  the  posterior 
ambulacra.  Ambulacra  dissimilar.  Inferambulacra  with  a  single  plate  at  the 
peristomal  margin;  the  postero-lateral  areas  usually  unsymmetrical  actinally. 
Fascioles  present  or  absenf. 


Family  4.     Ananchytidae  Desor. 

Test  ovoid  or  sub-cordiform  in  marginal  outline,  fall  or  depressed,  and  with  large 
plates.  Ambulacra  in  a  bivium  and  trivium,  nearly  similar,  flush,  apetalous  ;  pore- 
pairs  largest  near  the  apex  and  at  the  peristome,  may  be  uniporous.  Periproct 
variable  in  position.     Cretaceous  to  Recent. 

Ananchytes  Lam.  {Echinocorys  Breyn.)  (Fig.  4 1 4).  Test  large,  oval  in  marginal 
outline ;  high,  rounded  or  keeled  apically,  flat  actinally.  Amb  biporous,  the 
pore-pairs    well    developed    abactinally,    but    becoming    smaller,    closer    and 


CLASS  I 


ECHINOIDEA 


293 


Posterior  Amb 
Peristome  oval. 


oblique  toward  the  ambitus,  where  they  are  more  distant. 
actinally  long  and  broad,  the  pairs  small,  and  pores  oblique, 
broader  than  long.  Periproct 
infra- marginal,  posterior,  oval. 
Apical  System  elongate.  Very 
abundant  in  the  Upper  Cretac- 
eous.  A.  ovata  (Leske)  often 
attains  a  very  large  size. 

Holaster  Ag.  (Fig.  415).  Test 
ovoid  in  marginal  outline,  flat 
actinally,  tumid  and  high  abac- 
tinally.  Anterior  Amb  in  a  shal- 
low  groove.  Peristome  elliptical, 
broadest  transversely.  Periproct 
supra-marginal,  and  oval.  Apical 
System  elongate.  Cretaceous 
and  Miocene. 

Offaster  Desor.  Test  small, 
tumid.  Anterior  Amb  sometimes 
in  a  shallow  groove.  Peristome 
oval,  broadest  transversely.  Peri- 
proct supra-marginal,  circular  or 
ovoid.  Apical  system  elongate. 
Cretaceous.     0.  pilula  (Ag.). 

Hemipneustes  Ag.  Test  large, 
ovoid  in  marginal  outline,  high 
and  tumid  dorsally,  flat  actinally. 
Anterior  Amb  in  a  deep,  narrow 
groove  extending  to  the  elongate  apical  System,  its  pairs  of  pores  numerous 


Fig.  414. 

Ananchytes  ovata  (Leske).  White  chalk  ;  Haldem,  West- 
phalia.  Ä,  B,  Profile  and  ventral  view.  1/3.  C,  Apical  system, 
enlarged.    D,  Portion  of  Amb  and  lAmb  areas.     1/1. 


Fio.  415. 
A,  B,  Ilolaster  suhglobosus  Ag.   Cenomanian  ;  Ronen,     l/i-    C,  H.  mhorbiciilaris  Defr.     Apical  system,  enlarged. 

and  small,  the  vertical  rows  wide  apart.     Paired  Amb  more  or  less  curved, 
open    distally,    with    dissimilar    pores.      Peristome    much    sunken,    crescent- 


294 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


shaped,  broad.      Periproct  supramarginal.     Upper  Cretaceous.     H.  radiatus 
(Lam.). 

Cardiaster  Forbes.  Similar  to  Holaster,  but  anterior  groove  deeper  and 
with  angular  margin.  Periproct  oval,  placed  in  a  depression  in  the  truncated 
posterior  face.  A  more  or  less  complete  marginal  fasciole  passing  below  the 
periproct.     Cretaceous. 

Subgenus  Infulaster  Hagw.  Test  high  in  front,  narrow  ;  anterior  groove  deep  and  with 
strong  lateral  keels.     Fasciole  absent.     Upper  Cretaceous. 

Urechinus  and  Cystechinus  A.  Agassiz.  Late  Tertiary  and  Eecent.  Calymne 
Wyv.  Thomson.  Eecent.  Enichaster  de  Loriol.  Oligocene.  All  with  uni- 
porous  Amb. 

Stenonia  Desor.  Like  Ananchytes,  except  that  the  apical  System  is  com- 
pact, and  the  Amb  equal.  The  solitary  species,  S.  tuherculata  (Defr.),  is 
abundant  in  the  Upper  Cretaceous  (Scaglia)  of  the  Southern  Alps  and  the 
Apennines. 

Family  5.     Spatangidae  Wright. 

Test  ovoid  or  cordiform,  longer  than  broad,  with  numerous  jplates,  and  usually 
with  an  anterior  groove.  Ambulacra  in  a  bivium  and  trivium,  the  anterior  differing 
from  the  others  in  shape  and  construction.  Pore-pairs  of  the  petaloid  parts  differing 
from  the  others.     Fascioles  present  or  absent.     Cretaceous  to  Eecent. 


Section  A.     Adetes.     All  fascioles  absent. 


Isaster  Desor.      Petals   not  closed. 
labrum.     Cretaceous. 

Epiasier  d'Orb.  {Macraster  Eoemer). 


Peristome    large,    with   a  posterior 


Anterior  Ainb  in  a  groove ;  paired 
Amb  petaloid  dorsally,  with 
elongate,  unequal  pores.  lAmb 
tumid  dorsally.  Peristome  trans- 
verse,  tumid  in  front,  and  usu- 
ally with  a  projecting  labrum. 
Periproct  longitudinal,  supra- 
marginal.    Cretaceous. 

Toxäster  Ag.  {Echinospatagus 
Breyn.)  (Fig.  416).  Anterior 
Amb  in  a  broad  shallow  groove, 
with  unequal  pore-pairs.  Paired 
Amb  sub-petaloid,  flexuous,  with 
unequal    poriferous    areas    and 

unequal    pore  -  pairs.       Peristome    transverse,    sub  -  circular    or    pentagonal. 

Tubercles  small,  perf orate  and  crenulate.     Abundant  in  Lower  and  Middle 

Cretaceous. 

Ennalaster  d'Orb.  (Heteraster  d'Orb. ).     Petaloid  parts  of  antero-lateral  Amb 

divergent,  flexuous,  tending  to  close,  and  with  very  unequal  poriferous  areas, 

of  which  the  posterior  are  the   largest;  pore-pairs  oblique.     Postero-lateral 

Amb  Short,  divergent.     Peristome  labiate,  wide,  arched  in  front.     Periproct 

in  posterior  truncation.     Cretaceous. 

Hemipatagus   Desor  (Fig.   417).     Test    small,    cordiform.     Anterior  Amb 


Toxäster  complanatus  Ag 


Fig.  416. 
Neocomian ;  Auxerre,  Yonne. 


Vi. 


CLARS  I 


ECHINOIDEA 


295 


with   small   pores   in   a  shallow  furrow.     Paired  Amh  long,  petaloid,  nearly 

A  C 


Hemipatagiis hofmanni Goldf.  Oligocene ; 
Doberg,  near  Bünde.  A,  Dorsal  view. 
B,  Profile.  C,  Ventral  aspect.  i/i  (after 
Goldfuss). 

flush.     The  lateral  lÄmh  with  a  few  large  perforate  and  crenulate  tubercles 
in  deep  scrobicules.     Periproct  supra-marginal.     Tertiary. 

Platyhrissus  Grube.     Recent.     Palaeopneustes  A.  Ag.     Recent,  and  perhaps 
Eocene. 


Section  B.     Prymnadetes.     Suhanal  fasciole  ahsent,  other  fascioles  present. 
Hemiaster  Desor  (Fig.  418).     Anterior  Amb  in  a  shallow  groove,  the  pores 


Fio.  418. 


Hemiaster  orbignyanus  Desor.     Upper  Cretaceous  ;  Martigues,  Provence  (after  d'Orbigny).     A-C,  Ventral,  dorsal 
and  side  views  of  test,  Vi-    ^.  Pores  of  the  anterior  Amb.    E,  Peres  of  the  paired  Amb,  enlarged. 


Fio.  419. 
Linthia  heberti  Cotteau.     Eocene  ;  Lonigo,  near  Vicenza.    3/^  natural  size  (after  Dames). 

oblique,  and  in  pairs  on  either  side.     Antero-lateral  Amh  petaloid  dorsally, 
sunken,  diverging,  and  much  longer  than   the  postero-lateral.     Pores  of  the 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


petaloid  pärts  conjugated,  the  outer  ones  usually  the  largest.     Peripetalous 
fasciole  present. 

Subgenus  Tripylus  Pliill.  {Ahatus  Troschel).     Recent. 

Faorina  Gray.  Recent.  Pericosmus  Ag.  Cretaceous  and  Tertiary. 
Linthia  Merian  (Besoria  Gray)  (Fig.  419).  Anterior  Amb  in  a  deep 
groove,  the  pores  round  and  small,  in  pairs  on  either  side.  Antero-lateral 
Ami)  longer  and  more  divergent  than  the  others,  with  petals  sunk  in  grooves. 
Pores  conjugated.  A  peripetalous  and  lateral  fasciole  present.  Cretaceous 
to  Recent. 

Schizaster  Ag.  (Figs.  420,  421).  Resembling  Linthia,  but  the  apical  System 
is  posteriorly  eccentric,  and  the  Amb  very  diverse. 
Tertiary  and  Eecent. 

Prenaster  Desor;   Ornithaster  and  Coraster  Cotteau. 
Eocene. 

Agassizia  Val. ;  Moira  A.  Ag.     Tertiary  and  Recent. 
Hs  A.  Ag.     Recent. 


Fig.  420. 

Schizaster  arcMaci  Gott. 
Eocene ;  San  Giovanni  Ila- 
rione,  near  Vicenza. 


Fig.  421. 

Schizaster  fragilis  Ag.     Apical  Sys- 
tem, greatly  enlarged  (after  Loven). 


i«  Fig.  422. 

Micraster  coranganius 
(Ijam.).     Apical  System. 


Section  C.     Prymnodesmia.     Subanal  fasciole  present. 

Micraster  Ag.  (Figs.  422,  423).  Test  cordiform,  tumid,  rather  depressed. 
Anterior  Amb  apetaloid,  in  a  shallow  depression ;  antero-lateral  Amb  sub- 
petaloid  dorsally,   diverging ;    postero-lateral   shorter   than  the  others,  with 


Fin.  423. 
Micraster  cortestiulinarius  Goldf.     White  Chalk  ;  Meudon,  near  Paris.     Natural  size. 


CLASR  I  ECHINOIDEA  297 

elongate,  conjugated  pores.  Periproct  supra-marginal ;  apical  System  eccentric 
in  front.  Broad  subanal  fasciole.  Abundant  in  Middle  and  Upper  Cretaceous  ; 
less  common  in  Eocene  and  Miocene. 

JBrissus  Gray  {Brissomorpha  Laube) ;  Meoma  and  Metalia  Gray.  Tertiary 
and  Recent.     Bhinobrissus  A.  Ag.     Recent. 

Brissopsis  Ag.  (DeaJcia  Pavay)  (Fig.  424).  Amb  unequal,  bare  and  large 
near  the  peristome.  Anterior  Amb  slightly  sunken,  with 
small  pairs  of  close  pores.  Paired  Amb  sunken,  the 
antero- lateral  pair  sub-petaloid,  equal  to  or  larger  than 
the  postero-lateral,  straight  or  curved.  A  subanal  and 
peripetalous  fasciole.     Tertiary  and  Recent. 

Subgenus   Cydastcr  Cotteau.      Antero  -  lateral    Amh    divergent. 
Eocene. 

Brissopatagus  Cotteau.     AUied  to  Brissopsis.     Eocene. 

Spatangus  Lam.    Anterior  Amb  in  a  broad,  deep  groove,  ^^^  ^2^ 

with  distant  pairs  of  small  pores.     Paired  Amb  petaloid,      Brisso2J:sis   lyHfera 
with    broad,    sunken    poriferous    areas.      Periproct  large,   J^jar^ed f^terLovIn?"' 
supra-marginal,   transverse.      lAmb  with   large    crenulate 
and  perforate  primary  tubercles,  and  fine  granulation.     Subanal  fasciole  only. 
Tertiary  and  Recent. 

Maretia  Gray.     Tertiary  and  Recent. 

Eupatagus  Ag.  Anterior  Amb  in  a  shallow,  abactinal  depression,  narrow, 
and  with  small,  distant  pore-pairs.  The  paired  Amb  petaloid  dorsally,  long, 
wide,  closed ;  poriferous  areas  broad,  more  or  less  sunken ;  pores  dissimilar. 
Peripetalous  and  subanal  fasciole.     Tertiary  and  Recent. 

Subgenus  Macropneustes  Ag.  {Peripneustes  Cott.)  (Fig.  425).  Test  large,  thick,  cordiform. 
Petals  elongate  or  broad,  grooved  or  semi-flush,  open  or  imperfectly  closed.  Poriferous  areas 
of  equal  widtli  witli  the  interporiferous.     Eocene  and  Recent. 

GuaUieria  Desor;  Eocene.  Echinocardium  Gray  (Fig.  371,  F) ;  Breynia 
Desor ;  Lovenia  Ag.  and  Desor.     Tertiary  and  Recent. 

Section  D.     Apetala. 

Ambulacra flush,  apetalous,  generally  uniporous,  and  either  similar  or  diverse; 
plates  high,  few,  oflen  hexagonal.     Fascioles  usually  present 

Under  this  head  are  included  the  following  Recent  genera,  all  but  the  first 
two  of  which  have  fascioles  :  Genicopatagus  and  Palaeobrissus  A.  Ag. ;  Aceste 
Wy V.  Thomson ;  Aeropsis  Mortensen ;  Palaeotropus  Lov6n ;  Homolampas, 
Argopatagus  A.  Ag. ;  and  Cleistechinus  de  Loriol.     Miocene. 

Family  6.     Palaeostomatidae  Mortensen. 

Test  thin,  ovoid.  Apical  System  with  three  genital  plates  fused  into  one. 
Peristome  eccentric  in  front,  pentagonal,  with  five  angular  plates. 

Palaeostoma  Lov6n  (Leskia  Gray).     Recent ;  China,  East  Indian  Islands. 

Family  7.     Pourtalesiidae  Loven. 

Test  very  elongate,  sub-cylindrical  or  obconical,  truncated  anterimiy,  flat  actinally. 
Peristome  in  a  deep  anterior  recess  ;  periproct  actinal,  or  above  the  pyrojecting  posterior 


298 

rostrum  wlien  such 


ECHINODERMATA— ECHINOZOA 


PHYLüM  IV 


Amhulacra  flush,  apetalous,  sometimes  discontinuous  ; 
pores  Single  or  slit-Uke. 

Pourtalesia,  Spatagocystis 
and  Echinocrepis  A.  Agassiz. 
Recent. 

Order  5.     PLESIOCIDA- 
ROIDA    Duncan. 

Test  regulär,  endocyclic. 
Genitals  largely  covering  the 
dorsal  surface.  Two  columns  of 
low  simple  plates  in  each  am- 
bulacral  area  and  three  columns 
of  plates  in  each  interamhulacral 
area.  Plates  not  imbricate. 
Primordial  interamhulacral 
plates  in  basicoronal  row.  Base 
of  Corona  not  resorhed.  Oculars 
small,  strongly  exsert  hy  the  con- 
tact  of  large  genitals.  Peri- 
proct  central,  structure  unknown. 
Peristome  central,  structure  un- 
known. Lantern  and  perigna- 
thic  girdle  unknown. 


Family  1.     Tiarechinidae 

Zittel. 

The  Single  primordial  plate 
of  the  interambulacra  followed 
hy  three  elongated  plates  only, 
one  on  either  side  of  a  narrow 
median  plate.  Trias. 
Tiarechinus  Neumayr  (Fig.  426).     The  test  of  this  unique  genus  is  very 

small,  flat  actinally,  and  sub-hemispherical  dorsally.     Below  the  ambitus  and 

actinally  the    Ornament    consists    of    a    piain 

primary  tubercle  to  each  plate ;  elsewhere  the 

test  is  coarsely  granulär,  including  the  very 

large    apical   System.      The    solitary    species, 

T.  princeps  (Laube),  occurs  in  the  Trias  of  St. 

Cassian,  Tyrol. 

Our  knowledge  of  this  genus  and  family  is 

based  largely  on  Lov6n's  study  of   a   single 

minute  specimen.     As   it  has   three  columns 

of   plates  in    an    interamhulacral    area,   it  is 

considered  a  further  remove  from  the  primi- 
tive than  those  types  with  two  columns.     Three  plates,  representing  three 

columns,  immediately  succeeding  the  primordial   interamhulacral  plate,  is  a 

unique  character  in  Echini. 


Fig.  425. 

Macropneustes  meneghinii  Desor.    Eocene  ;  Monte  Spiado,  near 
Vicenza. 


Fio.  426. 

Tiarechinus  %ii-inceps  (Laube).  Upper  Trias ; 
St.  Cassian,  Tyrol.  Ventral  and  lateral 
aspects,  mncli  enlarged  (after  Loven). 


CLASR  I  ECHINOIDEA  299 


Order  6.     ECHINOCYSTOIDA   Jackson. 

Test  irregulär,  periproct  apparently  in  'an  interamhulacrum.  Two  to  four 
columns  of  plates  in  an  ambulacral  area,  and  eight  to  nine  columns  of  plates  in  an 
interamlmlacral  area.  Plates  thin,  imbricating.  Oculars  and  genitals  doubtful. 
Silurian. 

Members  of  this  order  have  been  considered  primitive,  but  structural 
evidence  is  opposed  to  this  view.  This  order  includes  the  only  exocyclic 
Echini  excepting  that  of  the  Exocycloida.  The  species  are  incompletely 
known. 

Family  1.     Palaeodiscidae    Gregory. 

Two  columns  of  plates  in  an  ambulacral  area  and  eight  to  nine  columns  of  plates 
in  an  interambulacral  area.  Primordial  interambulacral  plates  in  basicoronal  row. 
Base  of  corona  not  resorbed,  Peristome  with  ambulacral  plates  only.  Lantern 
inclined,  typically  echinoid.     Numerous  fine  spines. 

Palaeodiscus  Salter.  With  characters  of  the  family.  The  only  genus 
known,  many  rows  of  ambulacral  plates  on  the  peristome.  Silurian ; 
England. 

Family  2.     Echinocystidae   Gregory. 

Four  columns  of  plates  in  an  ambulacral  area,  and  eight  columns  of  plates  in  an 
interambulacral  area.     Small  primary  spines  and  tubercles.     Jaws. 

Echinocystites  Wyv.  Thomson  (Cystocidaris  Zittel).  With  characters  of  the 
family.     The  only  genus  known.     Silurian  ;  England. 


Order?.     PERISCHOEOHINOIDA   M'Coy. 

Test  regulär,  periproct  within  the  oculogenital  ring.  Two  to  twenty  columns  of 
simple  plates  in  each  ambulacral  area,  and  three  to  fourteen  columns  of  plates  in  each 
interambulacral  area.  Plates  imbricate  or  not.  Primordial  ambulacral  plates  on 
peristome.  Primordial  interambulacral  plates  in  basicoronal  row,  or  resorbed.  Base 
of  Corona  not  resorbed  or  resorbed.  Oculars  usually  all  insert.  Genitals  small, 
typically  with  more  than  one  pore  each ;  rarely  (Lepidechinus)  with  one  pore  each. 
Madreporite  usually  not  recognisable.  Periproct  covered  with  many  thick  plates. 
Peristome  with  many  rows  of  ambulacral  plates  only,  oi'  in  addition  with  interradial 
non-ambulacral  plates.  Lantern  inclined,  composed  of  forty  pieces,  teeth  grooved, 
foramen  magnum  moderately  deep,  epiphyses  narrow,  no  pits  in  top  of  pyramids. 
Spines  primary  and  secondary,  or  the  latter  only.  Primary  tubercles  perfm'ate, 
secondary  tubercles  imperforate.     Silurian  to  Permian. 

This  Order  includes  the  majority  of  Paleozoic  Echini.  All  are  specialised 
in  having  multiple  columns  of  interambulacral  plates,  and  in  many  genera 
multiple  columns  of  simple  ambulacral  plates  as  well ;  the  order  is  therefore 
considered  a  further  remove  from  the  primitive  than  are  those  Orders 
with  two  columns  of  both  interambulacral  and  ambulacral  plates. 


300 


ECHINODERMATA— ECHINOZOA 


PHYLÜM  IV 


Family  1.     Archaeocidaridae   M'Coy. 

Two  columns  of  plates  in  an  ambulacral  area.  Four  to  eight  columns  of  plates 
in  an  interambulacral  area,  imbricating .  Primordial  and  additional  interambulacral 
plates  are  resorhed  in  the  advance  of  peristome.  Oculars,  genitals  and  periproä 
imperfeäly  known.  Peristome  with  many  rows  of  ambulacral  and  interradial  non- 
ambidacral  plates.  Spines  large  primaries  with  perforate  tubercles  in  the  cenire  of 
each  inferambidacral  plate,  also  secondary  spines  and  imperforate  tubercles.  Devonian 
to  Permian. 

Eocidaris  Desor.  Known  from  fragmentary  interambulacral  plates  and 
spines,  primary  tubercles  of  plates  without  a  basal  terrace.  Only  one  species 
is  recognised,  E.  laevispina  (Sandb.).     Devonian;  Germany. 

Archaeocidaris  M'Coy.  Ambulacral  plates  all  alike,  of  equal  height.  Four 
columns  of  plates  in  an  interambulacral  area.  Primary  spines  large,  tapering 
or  inflated,  smooth  or  with  lateral  spinules.  Primary  tubercles  with  basal 
terrace  and  scrobicular  ring.  Many  species  fragmentarily  known.  The  most 
completely  known  are  A.  wortheni  Hall  (Figs.  366,  e;  371,  Cy  427,  Ä-C\ 
A.  rossica  (Buch),  A.  urii  (Flem.).  Lower  Carboniferous  and  Carboniferous ; 
Europe  and  North  America.     Permian  ;  North  America  and  India. 


Fio.  427. 


Archaeocidaris  wortheni  Hall.  Lower  Carboniferous;  Burlington,  Iowa.  A,  Portion  of  ventral  rogion, 
showing  jaws,  i/i.,  B,  An  lArab  plate  viewed  from  above  and  from  the  side.  C,  Portion  of  Amh,  enlarged. 
D,  Spina  of  A.  keokuk  Hall.     Lower  Carboniferous  ;  Warsaw,  Illinois  (after  Hall), 

Lepidocidaris  Meek  and  Worthen.  Ambulacral  plates  low,  with  also  higher, 
wider  and  wedge-shaped  plates.  Six  to  eight  columns  of  plates  in  an  inter- 
ambulacral area.  Primary  spines  cylindrical.  Primary  tubercles  with  no 
basal  terrace,  but  with  a  scrobicular  ring.  Lower  Carboniferous  ;  North 
America. 

Family  2,     Lepidocentridae   Loven. 

Two  columns  of  plates  in  each  ambulacral  area.  Five  to  fourteen  columns  of 
plates  in  an  interambulacral  area.  Primordial  interambulacral  plates  in  basicoronal 
row.  Base  of  Corona  not  resorbed.  Oculars  insert.  Genitals  with  many  pores  each. 
Peristome  with  many  rows  of  ambulacral  plates  only.     Spines  small  eccentrically 


CLASS 


ECHINOIDEA 


301 


placed    primaries   with    secondaries,    or   the    latter   only.       Siluriari    to    Lower. 
Carboniferous. 

Koninckocidaris   Dollo    and    Buisseret.     Test   high,  probably   spheroidal ; 
ambulacral  plates  high,  two  or  three  equalling  the  height  of  an  adambulacral 


Fig.  428. 


A,  Lepidmentrus  rhenanus  (Beyr.).  üevonian  ;  Wipperfürth,  Eifel.  Gast  of  the  interior  of  test  showing 
jaws,  l/i  (after  J.  Müller).  B-D,  Lejüdocentrus  mülleri  Schultze.  Devonian  ;  Gerolstein,  Eifel.  B,  Portion  of 
Amh,  enlarged.     C,  Several  lAmb  plates,  l/i  ».  D,  Two  detached  lAmb  plates,  showing  oblique  edges,  i/j. 

plate,  pore-pairs  uniserial.  Seven  to  eight  columns  of  nearly  rhombic  plates 
in  an  interambulacral  area.  K.  silimca  Jackson.  Silurian ;  North  America. 
K.  cotteaui  Dollo  and  Buiss.     Lower  Carboniferous ;  Belgium. 

Lepidocentrus  Müller  (Fig.  428).     Test  high,  spheroidal,  ambulacral  areas 
narrow  throughout ;  ambulacral  plates  low,  about  eight  equalling  the  height 


0«2   4    « 


Fig. 


A,  Hyattecliinus  pentagonus  Jackson.  External  sandstone  moulds.  Lower  Carboniferous;  Meadville, 
Pennsylvania.  Ventral  view  showing  introduction  of  columns  and  accelerated  development  of  interanibulacra. 
B,  The  same,  dorsal  view,  showing  fourteen  columns  in  each  interambulacral  area  and  the  dropping  out 
of  soine  columns  dorsally.    Both  figures  ^/lo  natural  size  (after  Jackson). 

of  an  adambulacral  plate,  pore-pairs  uniserial.  Five  to  eleven  columns  of 
plates  in  an  interambulacral  area.  Small  primary  spines  and  tubercles  with 
secondaries  on  interambulacral  plates.  Devonian ;  Germany  and  North 
America.     Lower  Carboniferous  ;  North  America. 

Hyattechinus  Jackson  (Fig.   429).     Test  depressed  to  flattened ;  through 
the  ambitus  circular,  pentagonal  or  clypeastriform.     Ambulacral  areas  broad, 


302 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


petaloid  ventrally,  narrow  dorsally,  pore-pairs  uniserial.  Eleven  to  fourteen 
columns  of  plates  in  an  interambulacral  area.  Small  primary  and  secondary 
tubercles  on  interambulacral  plates.  This  genus  is  highly  specialised, 
particularly  as  regards  the  interambulacra  which  attain  the  greatest  number 
of  columns  of  plates  and  the  most  accelerated  development  of  the  same  known 


A,  Palaeechinus  quadriserialis  Wright.  Lower  Carboniferous ;  Rathkeale,  County  Liinerick,  Ireland,  i/^. 
B,  Apical  disk  of  same,  2/j.  Restorations  indicated  by  dotted  lines.  C,  Same  species,  Middleton,  County 
Cork,  Ireland.     Ambulacral  detail,  enlarged  (after  Jackson). 


in  Echini.  H.  rarispinus  (Hall)  is  a  greatly  flattened  species,  H.  pentagonus 
Jackson  is  pentagonal  in  outline,  and  H.  beecheri  Jackson  is  ventrally 
flattened  and  bilaterally  symmetrical.  Lower  Carboniferous  ;  North  America. 
Fholidechinus  Jackson.  Test  high,  spheroidal,  ambulacral  areas  narrow 
throughout,  pore-pairs  moderately  biserial.  Nine  to  ten  columns  of  plates  in 
an  interambulacral  area.  Secondary  spines  and  tubercles  only.  Lower 
Carboniferous ;  North  America. 


CLASS  I  ECHINOIDEA  303 

Family  3.     Palaeechinidae  M'Coy. 

Test  elliptical,  ohovate,  spherical  or  suhspheroidal.  Two  to  twelve  columns  of 
plafes  in  each  amhulacral  area,  ihree  to  eleven  columns  of  plates  in  each  inter- 
ambulacral  area.  Plates  not  imhricate,  hut  amhulacral  plates  hevel  over  the 
interambulacral  on  adradial  sutures.  Primordial  interambulacral  plates  resorhed. 
One  row  only  of  interambulacral  plates  resorbed  in  advance  of  the  peristome.  Oculars 
usually  all  insert,  genitals  usually  with  three  to  five  pores  each.  Peristome  with 
many  rows  of  amhulacral  and  some  interradial  non-amhulacral  plates  (Fig.  371,  D). 
Secondary  spines  and  imperforate  tuhercles  only.    Silurian  (?),  Lower  Carboniferous. 

Tliis  family  includes  more  species  than  any  other  in  the  Paleozoic.  It 
contains  genera  with  complex  ambulacra  composed  of  more  than  two  columns 
of  simple  plates  in  an  area,  and  the  species  in  development  pass  throngh 
stages  like  those  of  adults  in  all  lower  species  or  genera  in  the  family.  The 
interambulacral  plates  are  very  definite  in  form,  and  the  incoming  of  columns 
indicate  stages  in  development. 

Palaeechinus  M'Coy  (Figs.  367,  ^;  430:  431).     Two  columns  of  plates  in 


Fia.  431. 

Palaeechinus  elecjans  M'Coy.     Lower  Carboniferous  Limestxjne  ;  Ireland.     A,  Test,  Vi  (after  M'Coy). 
7i,  Apical  System,  more  than  twice  enlarged  (after  Jackson). 

each  amhulacral  area,  consisting  of  plates  which  are  all  primaries ;  pore-pairs 
uniserial.  Four  to  six  columns  of  plates  in  each  interambulacral  area.  In 
this  lowest  genus  the  amhulacral  detail  is  like  that  seen  as  a  developing  stage 
in  the  higher  genera  of  the  family.  The  test  is  elliptical,  P.  quadriserialis^ 
or  nearly  spherical,  P.  elegans.  Lower  Carboniferous ;  Europe  and  North 
America. 

Maccoya  Pomel  (Fig.  367,  k).  Two  columns  of  plates  in  each  amhulacral 
area,  consisting  of  plates  which  are  alternately  primaries  and  partially  or 
completely  occluded  ;  pore-pairs  biserial.  Four  to  eight  or  nine  columns  of 
plates  in  each  interambulacral  area.  In  this  genus,  ventrally  and  dorsally, 
amhulacral  plates  as  stages  in  development  are  all  primaries  as  in  Palaeechinus. 
M.  phillipsiae  Forbes  is  attributed  to  the  Silurian  (?)  of  England,  other  species 
Lower  Carboniferous ;  Europe  and  North  America. 

Lovenechinus  Jackson  (Figs.  367,  /;  432).  Four  columns  of  plates  in  each 
amhulacral  area,  consisting  of  demi-  and  occluded  plates ;  pore-pairs  biserial. 
Four  to  seven  columns  of  plates  in  each  interambulacral  area.  While  in  this 
genus  there  are  four  columns  of  amhulacral  plates  at  the  mid-zone,  primary 
plates  as  a  stage  occur  ventrally  and  dorsally,  L.  septies.  In  L.  missiouriensis 
(Jackson)  primary  with  occluded  plates  exist  both  ventrally  and  dorsally  as  a 


304 


ECHINODERMATA— ECHINOZOA 


PHYLUM  IV 


second   developmental    stage.       Lower    Carboniferous  ;    Europe    and    North 
America. 

Oligoporiis  Meek  and  Worthen  (Fig.  367,  m).  Four  columns  of  plates  in 
each  ambulacral  area,  consisting  of  demi-,  occluded,  and  in  addition  scattered 
isolated  plates  ;  pore-pairs  multiserial.     Four  to  nine  columns  of  plates  in  each 

J 


Fig.  432. 

Lovenechinus  septies  Jackson.  Lower  Carboniferous  ;  Boonville,  Missouri.  A,  In  the  centre,  spread  out  to 
show  structure  and  development,  dotted  lines  indicate  restorations.  B,  Lower  left-hand  figure,  developing 
ambulacrum  ventrally,  C,  Lower  right-hand  ligure,  ambulacrum  near  mid-zone.  D,  Upper  riglit,  developing 
ambulacrum  dorsally.  E,  Upper  left,  apical  disl<  with  coronal  contact.  A,  Natural  size ;  other  ligures  three 
times  enlarged  (after  Jackson). 

interambulacral  area.  This  genus  differs  from  Lovenechinus  in  that  it  has 
isolated  plates  in  addition  to  the  four  columns  of  ambulacral  plates.  Lower 
Carboniferous ;  North  America. 

Melonechimis  Meek  and  Worthen  (Melonifes  Norwood  and  Owen).  (Figs. 
366,  d;  367,  n;  371,  D;  433).  Six  to  twelve  columns  of  plates  in  each 
ambulacral    area,   consisting  of   demi-,   occluded    and   one  to  four   irregulär 


CLASR  I 


ECHINOIDEA 


305 


columns  of  isolated  plates  in  each  half-area  at  the  mid-zone ;  pore-pairs 
multiserial.  Three  to  eleven  columns  of  plates  in  each  interambulacral  area. 
This  genus  has  fourteen  species  with  a  wide  ränge  of  characters.  The  lowest 
species,  M.  dispar  (Fischer  von  Waldheim)  has  six  columns  of  ambulacral 
plates,  and  is  thus  only  one  remove  from  Oligoporus.  The  highest  species, 
M.  giganteus  (Jackson)  has  twelve  columns  of  ambulacral  plates.  At  the 
ventral  border  of  the  ambulacra  there  are  typically  four  columns  of  plates 
like  the  adult  of  Lovenechinus.  From  this  stage  passing  dorsally  isolated 
plates  first  appear  like  Oligoporus,  then  additional  columns,  until  the  number 


Fio.  433. 

MdonecMnus  viultiporuf^  (Norwood  and  Owen).     Lower  Carboniferous  ;  St.  Lonis,  Missouri. 
1/2  natural  size.     B,  Apical  System,  slightly  enlarged  (after  Meek  and  Worthen). 


A,  Test, 


characteristic  of  the  species  is  attained.  Dorsally  some  primary  plates  occur 
next  the  oculars.  Each  species  of  Melonechinus  presents  developmental  stages 
in  the  ambulacrum  like  the  adults  of  all  lower  genera,  and  lower  species  in 
the  family.  The  interambulacrum  may  have  as  few  as  three  columns  of 
plates,  as  in  AI.  obovatus  Jack.,  which  is  the  least  known  in  the  family,  though 
this  species  has  ten  columns  of  ambulacral  plates ;  or  there  may  be  eleven 
columns  of  plates  as  in  the  extreme  form,  M.  giganteus  (Jackson).  Between 
the  extremes  every  step  is  represented  in  the  genus  by  developmental  or 
adult  characters,  or  both.  Plates  of  the  test  are  often  very  thick,  and  usually 
more  or  less  strongly  elevated  melon-like  ribs  occur  in  both  ambulacra  and 
interambulacra,  though  these  may  be  obsolescent  or  wanting,  M.  etheridgii 
(Keeping).  The  peristome  is  known  only  in  this  genus  for  the  family 
(Fig.  371,  D).     Lower  Carboniferous;  Europe  and  North  America. 


Lepidesthidae  Jackson. 

Test  elliptical,  ohovate,  spherical  m'  subspheroidal.  Two  to  twenty  columns  of 
plates  in  each  ambidacral  area.  Three  to  thirteen  columns  of  plates  in  each  inter- 
ambulacral area.  Plates  imbricate.  Primordial  interambulacral  plates  in  basicoi'onal 
row.  Base  of  Corona  not  resorbed.  Oculars  usually  all  insert,  genitals  with  one  to 
many  pores  each.  Periproct  plated  wit\  many  thick  plates.  Peristome  with  many 
rows  of  ambulacral  plates  only.     Primary  spines  with  perfoi'ate  tubercles^  usually 

VOL.  I  X 


306  ECHINODEEMATA— ECHINOZOA  phylum  iv 

eccentric  and  irregularly  distributed  on  interamhulacral  plates,  with  secondary  spines 
and  tubercles,  or  the  latter  only.     Devonian  to  Permian. 

This  family  presents  a  wide  ränge  of  characters,  and  includes  species  with 
very  specialised  features,  particularly  as  regards  an  extreme  development  of 
ambulacral  areas. 

Lepidechinus  Hall  (Ehoechinus  Keeping).  Two  columns  of  plates  in  each 
ambulacral  area.  Four  to  eight  columns  of  plates  in  each  interamhulacral 
area.  Plates  quite  thick,  imbricating  moderately.  Secondary  tubercles  only. 
Genital  plates  as  far  as  known  with  only  one  pore  each,  the  only  instance 
known  in  the  Paleozoic.  This  genus,  the  lowest  of  the  family,  difFers  from 
Palaeechinus  which  it  approaches,  principally  in  the  fact  that  the  plates  are 
imbricate.  The  genus  has  been  misunderstood  because  Hall  referred  to 
it  the  species  rarispinus,  which  is  now  referred  to  Hyattechinus.  Lower 
Carboniferous  ;  Europe  and  North  America. 

Perischodomus  M'Coy  (Fig.  366,  h).  Two  columns  of  plates  in  each  am- 
bulacral area.  Five  columns  of  plates  in  each  interamhulacral  area.  Plates 
imbricating  strongly.  Eccentric  perforate  primary  with  secondary  tubercles 
on  interamhulacral  plates.  Genital  plates  with  many  pores.  The  most 
completely  known  species  is  P.  biserialis  M'Coy,  Lower  Carboniferous  of  Great 
Britain ;  a  second  imperfectly  known  is  P.  iUinoisensis  Worthen  and  Miller, 
Lower  Carboniferous  ;  North  America. 

Perischocidaris  Neumayr.  Six  columns  of  plates  in  each  ambulacral  area. 
Five  columns  of  plates  in  each  interamhulacral  area.  Plates  apparently 
imbricating  moderately.  Eccentric  primary  tubercles  on  certain  adradial 
plates,  with  secondary  tubercles  on  the  same  and  usually  alone  on  other 
interamhulacral  plates.     Lower  Carboniferous  ;  Ireland. 

Proterocidaris  Koninck.  Four  columns  of  plates  in  each  ambulacral  area. 
T.welve  to  thirteen  columns  of  plates  in  each  interamhulacral  area.  Plates 
strongly  imbricating.  Small  primary  with  secondary  spines  and  tubercles  on 
interamhulacral  plates.     Lower  Carboniferous  ;  Belgium. 

Lepidesthes  Meek  and  Worthen  {Eyboechinus  Worthen  and  Miller)  (Figs. 
365,  367,  0 ;  434).  Eight  to  sixteen  columns  of  plates  in  each  ambulacral 
area.  Three  to  seven  columns  of  plates  in  each  interamhulacral  area.  Plates 
are  strongly  imbricating  and  are  all  of  uniform  size.  Secondary  spines  and 
tubercles  only,  Test  elliptical,  obovate  or  spherical.  This  genus  has  more 
species  and  a  wider  geological  ränge  than  any  other  of  the  family.  Ambulacral 
plates  are  very  regulär  in  form,  either  rhombic  or  hexagonal.  There  may  be 
as  many  as  sixteen  columns  of  ambulacral  plates  in  an  area,  e.g.  L.  colletti 
White,  in  which  species  with  an  extreme  ambulacral  development  there  are 
only  four  columns  of  interamhulacral  plates  (Fig.  434).  In  one  species, 
L.  wortheni  Jackson,  there  are  eight  columns  of  ambulacral  plates  with  only 
three  columns  of  interamhulacral  at  the  mid-zone,  but  there  are  four  columns 
ventrally  as  a  youthful  stage.  Devonian  ;  Great  Britain.  Lower  Car- 
boniferous ;  Russia,  Great  Britain,  North  America.  Carboniferous ;  North 
America. 

Pholidocidaris  Meek  and  Worthen  (Protocidaris  Whidborne).  Four  to  six 
columns  of  plates  in  each  ambulacral  area.  Five  to  six  columns  of  plates  in 
each  interamhulacral  area.  Plates  strongly  imbricating.  Ambulacral  plates 
large  ventrally,  small  dorsally ;  interamhulacral  plates  dorsally  very  large  in 


ECHINOIDEA 


307 


adambulacral  columns,  smaller  within.  Eccentric  primary  spines  and  tubercles 
with  secondaries  on  dorsal  adambulacral  plates,  and  secondaries  only  on 
interambulacral  plates  of  dorsal  median  columns.  This  peculiar  and  specialised 
genus  is  known  best  from  the  type  species  P.  irregularis  (Meek  and  Worthen). 
Devonian  ;  Great  Britain.     Lower  Carboniferous  ;  Europe,  North  America. 


N 


Fig.  434. 

Lepidesthes  colletti  White.     Lower  Carboniferous  ;  Montgomery  County,  Indiana,     x  2^/2. 
Madreporite  and  periproctal  plates  distinet  (after  Jackson). 

Meekechinus  Jackson  (Fig.  435).  Twenty  columns  of  plates  in  each 
ambulacral  area.  Three  columns  of  plates  in  each  interambulacral  area. 
Plates  of  uniform  size,  imbricating  strongly.  Small  central  primary  spines 
and  tubercles  with  secondary  spines  and  tubercles  on  ambulacral  and  inter- 
ambulacral plates.  Teeth  distally  serrate,  a  unique  character.  This  genus 
with  a  Single  species  is  one  of  the  most  specialised  of  known  Echini,  also  it 
is  the  geologically  latest  representative  of  its  family.  The  twenty  columns 
of  ambulacral  plates  occur  only  near  the  mid-zone,  as  further  dorsally  less 
columns  exist.  This  is  the  only  Echinoid  from  the  Paleozoic  in  which 
pedicellariae  have  yet  been  found.     Permian  ;  North  America. 


308 


ECHINODERMATA— ECHINOZOA 


PHYLÜM  IV 


Geological  Range  and  Distribution  of  the  Bchinoidea. 

Fossil  Echini  make  their  first  appearance  in  the  Ordovician,  but  are  then 
represented  by  but  a  single  genus,  Bothriocidaris,  which  on  structural  grounds 
is  a  highly  primitive  type.  In  the  Silurian  of  Great  Britain  occurs 
the  Order  Echinocystoida,  and  in  the  American  Silurian,  Koninckocidaris,  first 
of  the  Lepidocentridae.  In  the  Devonian  one  possible  Cidarid  occurs  in 
Europe  and  a  number  of  genera  of  the  Perischoechinoida  in  Europe  and  North 


Fig.  435. 
Meehechinus  elegans  Jackson.     Permian  ;    Grand  Summit,  Kansas.      Dorsal  view  of  test  with  a  distinct 
madreporite  and  otherapical  plates,  enlarged,  2/^.     Lower  left-hand  flgure,  ambulacral  plates  with  spines  more 
enlarged.     Lower  right-hand  ügure  Segment  of  interambulacrum  with  spines  still  more  enlarged.     Upper  left- 
hand  figüre,  pedicellaria  much  enlarged,  45/j  (after  Jackson). 

America.  In  the  Lower  Carboniferous  the  Cidarids  are  represented  by  one 
species  of  Miocidaris ;  otherwise  the  whole  Echinoid  fauna  is  composed  of  the 
Perischoechinoida,  which  order  finds  here  its  greatest  development  in  genera 
and  species. 


CLÄSS  I  ECHINOIDEA  309 

In  the  Carboniferous  very  few  Echini  are  known,  and  these  belong  to  the 
Perischoechinoida.  The  same  order  is  represented  by  a  few  types  in  the 
Permian  which,  with  a  single  species  of  Miocidaris  representing  the  Cidaroida, 
are  the  only  Echini  known. 

In  the  Trias,  Cidarids  occur  and  also  the  earliest  representatives  of  the 
Centrechinoida.  In  the  same  horizon  also  occurs  Tiarechinus,  representing 
the  peculiar  order  Plesiocidaroida. 

Especially  rieh  in  regulär  Sea-urchins,  as  well  as  in  members  of  the 
Echinoneidae,  Cassidulidae  and  Collyritidae  are  the  Middle  and  Upper  Jura 
of  England,  France,  Germany,  Switzerland,  the  Alps  and  Northern  Africa. 
The  Lower  Cretaceous  of  the  same  region  exhibits  no  essential  change  in 
the  Echinoid  fauna ;  but  the  advent  of  large  numbers  of  the  Ananchytidae 
and  Spatangidae  in  the  Middle  and  Upper  Cretaceous  of  Europe,  Northern 
Africa,  Asia  and  North  America  imparts  to  these  horizons  a  characteristic 
appearance. 

During  the  Tertiary  the  Cidaridae  notably  decline,  the  Echinoconinae 
become  entirely  extinct,  and  the  Clypeastroids  and  Spatangoids  advance  con- 
spicuously  into  the  foreground,  taking  on  more  and  more  the  semblance  of 
Recent  species.  Tertiary  Echinoids  are  of  world-wide  distribution  and  are 
particularly  plentiful  in  the  Nummulitic  Limestone  of  Europe,  Northern 
Africa,  Asia  Minor  and  India. 

As  to  phylogenetic  relationships,  it  is  believed  that  strueture  and  develop- 
ment  should  be  the  basis  for  such  studies.  While  it  is  earnestly  desired  that 
we  should  find  fossils  in  the  proper  geological  horizons  representing  every 
Step  in  a  genealogical  sequence,  it  must  be  remembered  that  in  the  older 
Paleozoic  formations  (Silurian  and  Devonian)  Echini  are  extremely  rare. 
Eecent  studies  have  yielded  many  new  Paleozoic  forms  and  have  considerably 
extended  the  geological  ränge  of  genera,  families  and  Orders,  so  that  it  is  not 
too  much  to  expect  that  future  discoveries  will  yield  material  of  first 
importance  to  a  knowledge  of  the  group.  Echini  are  an  essentially  circum- 
scribed  group  and  no  known  type  presents  a  close  approach  to  any  other  class 
of  Echinoderms.  Though  the  ancestor  of  the  class  is  unknown,  it  seems  that 
it  might  fairly  be  sought  among  the  Cystids. 

The  most  primitive  known  Echinoid  structurally  is  the  Ordovician 
Bothriocidaris,  sole  representative  of  its  order,  which  in  the  adult  has 
characters  that  appear  as  stages  in  development  in  all  other  Orders  of  Echini. 
Bothriocidaris,  with  ten  columns  of  ambulacral  and  five  columns  of  inter- 
ambulacral  plates,  in  these  characters  represents  the  simplest  known  type. 

The  next  step  structurally  is  ten  columns  of  ambulacral  and  ten  of  inter- 
ambulacral  plates.  This  strueture  is  the  character  of  the  Cidaroida, 
Centrechinoida  and  Exocycloida.  Of  these  Orders  the  Cidaroida  with  simple 
ambulacral  plates  is  certainly  the  most  primitive  as  well  as  geologically  the 
oldest.  The  Centrechinoida  typically  have  Compound  plates  formed  by  the 
coalescence  of  simple  plates.  Of  this  order  the  Aulodonta  are  the  most 
primitive  group,  make  the  nearest  approach  to  the  Cidaroida  structurally,  and 
also  geologically  are  the  oldest  of  the  order.  The  Stirodonta  as  regards  the 
strueture  of  the  lantern  (keeled  teeth)  are  further  removed  from  the  primitive 
than  the  Aulodonta.  The  Camarodonta  are  the  last  expression  of  differentia- 
tion  of  the  Centrechinoida  in  regard  to  the  strueture  of  the  lantern  (keeled 
teeth  with  wide  epiphyses  joining  in  suture  over  the  foramen)  and  also  in 


310  ECHINODERMATA— ECHINOZOA  phylum  iv 

ambulacral  differentiation.  This  group  appears  last  geologically  and  has  its 
füllest  expression  at  the  present  time,  The  Exocycloida  with  an  eccentric 
periproct  is  a  homogeneous  group.  The  structure  of  the  lantern  (keeled 
teeth)  with  other  characters  affiliate  the  basal  members  with  the  Stirodonta. 
Of  this  Order  the  Holectypina  on  the  basis  of  the  lantern  structure,  perignathic 
girdle  and  ambulacral  detail,  make  the  nearest  approach  to  the  Stirodonta. 
The  Clypeastrina,  by  the  characters  of  the  lantern,  perignathic  girdle  and 
petaloid  ambulacra  composed  of  simple  plates,  are  further  removed  from  the 
primitive  than  the  Holectypina.  The  Spatangina,  which  have  lost  the  lantern 
in  adults  and  have  attained  an  extreme  of  differentiation  in  ambulacral 
structure,  bilaterality  and  an  eccentric  peristome,  may  well  be  considered  the 
most  specialised  group  of  the  Exocycloida,  and  therefore  the  furthest  removed 
from  the  primitive. 

Up  to  this  point  each  order  is  characterised  by  having  two  columns  of 
ambulacral  plates,  and  either  one  or  two  columns  of  plates  in  each  inter- 
ambulacral  area.  The  next  step  in  structural  differentiation  is  two  columns 
of  ambulacral  and  three  columns  of  interambulacral  plates.  This  is  the 
character  of  the  Plesiocidaroida  which  is  further  marked  by  an  exceptionally 
large  apical  disc  which  is  a  primitive  feature. 

The  next  step  structurally  is  types  with  two  or  more  columns  of  simple 
ambulacral  plates  and  three  or  more  columns  of  interambulacral  plates,  with 
a  small  apical  disk  which  is  a  progressive  character.  The  Echinocystoida 
with  eight  or  more  columns  of  interambulacral  plates  fall  in  this  group. 
This  Order  is  incompletely  known,  especially  as  regards  the  apical  disk  and 
the  periproct,  which  last  appears  to  be  eccentric  in  an  interambulacrum, 
separating  it  radically  from  all  of  the  Perischoechinoida.  The  Palaeodiscidae 
is  the  more  primitive  family,  with  two  columns  of  ambulacral  plates ;  the 
l^chinocystidae  is  the  more  specialised  family  with  four  columns  of  ambulacral 
plates. 

The  Perischoechinoida  include  all  remaining  Echini ;  primitive  as  regards 
the  lantern,  they  are  specialised  in  the  interambulacrum,  frequently  in  the 
ambulacrum,  and  also  in  having  a  small  apical  disk.  The  Archaeocidaridae 
have  two  columns  of  ambulacral  plates  and  in  so  far  are  primitive,  but  they 
have  from  four  to  eight  columns  of  interambulacral  plates ;  very  large  spines 
(for  the  Paleozoic)  ;  ambulacral  and  non-ambulacral  plates  on  the  peristome 
and  much  resorption  of  the  base  of  the  corona,  specialised.  *rhe  Lepido- 
centridae  have  also  two  columns  of  ambulacral  plates.  The  family  attains 
many  (5  to  14)  columns  of  interambulacral  plates,  progressive ;  ambulacral 
plates  only  on  the  peristome  and  no  resorption  of  the  base  of  the  corona, 
primitive.  The  Palaeechinidae  may  have  two  columns  of  ambulacral  plates 
only,  but  typically  more  (up  to  twelve)  with  three  to  eleven  columns  of 
interambulacral  plates ;  plates  not  imbricate,  secondary  spines  only,  ambu- 
lacral with  non-ambulacral  plates  on  the  peristome,  slight  resorption  of  the 
base  of  the  corona.  The  Lepidesthidae  may  have  two  columns  of  ambulacral 
plates  only,  but  typically  more  (up  to  sixteen  or  twenty)  with  three  to 
thirteen  columns  of  interambulacral  plates,  plates  imbricate,  primary  and 
secondary  spines,  or  the  latter  only,  ambulacral  plates  alone  on  the  peristome, 
no  resorption  of  the  base  of  the  corona  as  far  as  known. 

In  almost  all  of  the  above  Orders  and  families  by  the  study  of  stages  in 
development,  characters  have  been  found  in  which  the  individual  repeats  the 


CLASS  I 


ECHINOIDEA 


311 


characters  seen  in  the  adults  of  the  preceding  series,  or  lower  members  of  its 
own  series. 


Geological  Range  of  the  Echini 


Orders  and  Faniilies  of  Echini. 

1 

"> 
o 

'H 
o 

i 

1 

1 

t-i  (-1 
ö 

'2 
2 

3 

i 

s 

£ 

i 

m 

1 

4^ 

g 
1 

Order  1.  Bothriocidaroida 
Order  2.  Cidaroida 
Order  3,  Centrechinoida 
Suborder  A.  Aulodonta 

1.  Hemicidaridae 

2.  Aspidodiadeniatidae 

3.  Centrechinidae 

4.  Echinothuriidae 
Suborder  B.  Stirodonta 

1.  Saleniidae 

2.  Pliymosomatidae 

3.  Storaopneustidae 

4.  Arbaciidae 
Suborder  C.  Camarodonta 

1.  Echinidae 

2.  Temnopleuridae 

3.  Strongylocentrotidae 

4.  Echinometridae 
Order  4.  Exocycloida 

Suborder  A.  Holectypina 
Suborder  B.  Clypeastrina 

1.  Clypeastridae 

2.  Fibulariidae 

3.  Scutellidae 
Suborder  C.  Spatangina 

1.  Echinoneidae 

2.  Cassidulidae 

3.  Collyritidae 

4.  Anancliytidae 

5.  Spatangidae 

6.  Palaeostomatidae 

7.  Pourtalesiidae 
Order  5.  Plesiocidaroida 
Order  6.  Echinocystoida 
Order  7.  Perischoechinoida 

..? 







-^— 





_ 

. 

r 

1 









! 



__ 

[To  Dr.  Robert  Tracy  Jackson,  of  the  Boston  Society  of  Natural  History,  acknowledgments 
are  due  for  having  revised  the  preceding  chapter  on  Echinoidea.  A  number  of  new  illustra- 
tions  have  been  reproduced  from  this  author's  recently  published  monograph  on  the  Phylogeny 
of  the  Echini. — Editou.] 


312 


ECHINODERMATA— ECHINOZOA 


PHYLÜM  IV 


Olass  2.    HOLOTHURIOIDEA  von  Siebold.i 

The  Holothurians,  or  Sea-cucumbers,  difFer  markedly  from  all  other 
Echinoderms  in  their  elongated  bodies  with  little  or  no  skeleton.  The  mouth 
and  anus  are  with  rare  exceptions  more  or  less  nearly  terminal  at  opposite 
poles,  and  the  former  is  always  surrounded  by  a  circle  of  tentacles,  8-30  in 
number.  The  skeleton  is  represented  by  calcareous  particles  in  the  body 
wall,  which  are  commonly  microscopic  and  dissociated,  but  are  sometimes 
several  millimetres  across,  and  in  rare  cases  may  even  be  closely  united  with 
each  other  to  form  a  rigid  body  wall.  In  some  species  skeletal  particles  are 
nearly  or  quite  wanting. 

The  paleontological  evidence  bearing  on  the  history  of  Holothurians  is 
very  slight.     Fossils  occur  in  two  forms,  either  as  impressions  or  casts  of  the 


Fkj.  435  Ms. 

Eldonia  ludwigi  Walcott.  Middle  Cambrian  (Burgess  shale  formation) ;  British  Columbia.  Specimen 
flattened  in  the  shale  and  showing  traces  of  internal  organs.  er  and  rc,  Central  ring  and  radial  canals  of 
vascular  System  ;  i,  Intestine  ;  o,  Oral  aperture  ;  oc,  Oral  Chamber ;  oe,  Oesoijhagus ;  s,  Stomach  ;  t, 
Tentacles ;  ul,  Umbrella  lobes,  crushed  and  macerated  ;  x-x,  Junction  -  point  of  i  stomach  and  intestine ; 
a,  Position  of  anus.     Natural  size  (after  Walcott). 

whole    animal,   or    as   dissociated    skeletal   particles  preserved   in   very  fine 
limestones  or  shales.       Of    impressions   or   casts,  the  earliest  described  are 

^  Literature  :  Giebel,  G.,  Zur  Fauna  des  lithographischen  Schiefers  von  Solenhofen.  Holothu- 
rienreste.  Zeits.  f.  gesammt.  Naturw.,  1857,  vol.  ix. — Schlumherger,  G.,  Note  sur  les  Holothuridees 
fossiles  du  Calcaire  Grossier.  Bull.  Soc.  Geol.  France  (3),  1888,  vol.  xvi. — Idem,  Second  Note 
sur  les  Holothuridees  fossiles.  Bull.  Soc.  Geol.  France  (3),  1890,  vol.  xviii. — Ludwig,  H.,  Die 
Seewalzen.  Bronn's  Klassen  und  Ordnungen  des  Thierreichs,  vol.  ii.,  part  3,  1889-92. — Spandel, 
E.,  Die  Echinodermen  des  deutschen  Zechsteins.  Abh.  Ges.  Nürnberg,  1898,  vol.  xi. — Idem,  Eine 
fossile  Holothurie.  Dp.  cit.,  1900,  vol.  "xiii. —  Wcdcott,  G.  D.,  Middle  Canibrian  Holothurians 
and  Medusae.  Smiths.  Mise.  Coli.,  1911,  vol.  Ivii.,  no.  3. — Glark,  H.  L.,  Fossil  Holothurians. 
Science,  1912,  n.s.  vol.  xxxv. — Glark,  A.  H.,  Restoration  of  Eldonia.     Zool.  Anz.,  1912,  vol.  xxxix. 


CLASS  II  HOLOTHURIOIDEA  313 

those  made  known  by  Giebel  from  the  Lithographie  limestone  of  Solenhofen. 
These  he  called  Protholoturia,  and  though  the  material  does  not  permit  of  exact 
generic  determination,  it  bears  a  resemblance  to  certain  Recent  species  of 
Holothuria  and  Pseudosiichopus.  The  impression  formed  by  the  general  appear- 
ance  of  these  specimens  that  they  really  represent  Holothurians  is  confirmed 
by  the  presence  of  characteristic  calcareous  particles  on  their  surface. 

Recently,  in  the  remarkably  well  -  preserved  fauna  from  the  Middle 
Cambrian  shales  of  British  Columbia,  Walcott  has  discovered  some  complete 
specimens  of  typical  Holothurians,  preserving  many  details  of  the  original 
animals.  Most  of  these  species  are  referred  by  A.  H.  Clark  to  the  family  Elpi- 
diidae  (a  group  of  very  remarkable  Holothurians  at  the  present  time  confined  to 
the  deep  sea),"but  one  of  them,  Eldonia  (Fig.  435  bis),  representing  the  new  family 
Eldoniidae,  was  free-swimming  like  the  Recent  Pelagothuria,  though  structurally 
entirely  difFerent  from  that  type,  being  most  nearly  related  to  the  Elpidiidae. 

Dissociated  calcareous  particles  referred  to  Holothurians  have  been 
described  by  a  number  of  writers  from  the  British  Carboniferous  rocks,  the 
Zechsbein  of  Germany,  the  Lias  and  Dogger  of  Lorraine,  the  Upper  Jura  of 
Franconia,  the  Cretaceous  of  Bohemia,  the  Eocene  of  Paris,  the  Oligocene  of 
Offenbach,  the  Pliocene  of  Italy  and  the  post-Tertiary  of  Scotland.  A  very 
large  majority  of  these  cannot  be  assigned  to  any  particular  genus  or  even 
family  of  Holothurians,  and  it  is  probable  that  many  if  not  most  are  of  other 
than  Holothurian  origin.  There  can  be  no  question,  however,  that  a  part 
of  this  material  is  of  real  paleontological  value.  In  particular  the  forms 
described  by  Schlumberger  and  by  Spandel  are  worthy  of  attention. 

Spandel's  discovery  of  what  seem  to  be  unquestionable  Holothurian 
spicules,  like  those  characteristic  of  the  genus  Chiridota,  in  the  Zechstein  of 
Germany,  is  noteworthy.  These  spicules  are  distinctly  wheel-shaped,  but 
differ  noticeably  from  those  of  Recent  Chiridota  in  having  10-14  spokes  instead 
of  six.  They  thus  show  a  certain  resemblance  to  the  wheels  of  Trochoderma 
and  the  first  formed  calcareous  deposits  of  the  larvae  of  Chiridota  rotifera  and 
certain  Auricularias.  Spandel's  later  discovery  of  an  Oligocene  Synapta,  and 
Schlumberger's  studies  on  the  Eocene  Holothurian  spicules  of  the  Calcaire 
Grossier,  show  that  during  the  Tertiary  period  the  Synaptidae  were  already 
difFerentiated  into  the  three  Recent  subfamilies,  Synaptinae,  Chiridotinae  and 
Myriotrochinae.     Beyond  this  grouping  we  cannot  speak  with  any  certainty. 

Our  actual  knowledge  of  fossil  Holothurians  may  be  summed  up  as  follows  : 

1.  Holothurians  allied  to  living  members  of  the  class  existed  in  the  Jurassic 
seas  of  Europe,  and,  according  to  Walcott's  Interpretation,  there  is  evidence 
that  the  typical  expression  of  the  group  was  already  differentiated  as  early 
as  the  Cambrian. 

2.  Holothurians  of  the  family  Synaptidae,  allied  to  Chiridota  or  Trochoderma 
occurred  in  the  Permian  seas  of  Europe ;  and  at  least  as  early  as  the  Eocene, 
all  three  of  the  Recent  subfamilies  of  Synaptidae  were  differentiated. 

3.  The  Permian  Holothurian  spicules  are  wheel-shaped  but  have  numerous 

spokes  as  in  Trochoderma,  and  resemble  those  of  the  larval  Chiridota,  not  those 

of  the  adult. 

[The  account  here  given  of  Holothurians,  with  the  exception  of  the  paragraph  in  regard 
to  Cambrian  repräsentatives  of  the  class,  has  been  contributed  by  Dr.  H.  L.  Clark  of  the 
Harvard  Museum  of  Comparative  Zoology.— Editor.] 


Phylum  V.    MOLLUSCOIDEA. 

Under  the  term  Molluscoidea,  Milne  Edwards  included  the  Bryozoa  and 
Tunicata,  of  which  the  first  had  been  previously  regarded  as  Zoophytes,  and 
the  second  as  Molluscs.  Huxley  afterwards  assigned  the  Brachiopoda  to  the 
same  phylum.  The  Tunicata  have  more  recently  been  regarded  as  an  in- 
dependent  animal  type,  and  as  possible  progenitors  of  the  Vertebrate  phylum. 
Their  remains,  however,  are  unknown  in  the  fossil  state.  Bryozoans,  also 
called  Polyzoa,  are  by  some  authors  regarded  as  constituting  a  distinct  phylum 
of  invertebrates,  but  are  here  retained  in  association  with  Brachiopods. 

The  typical  Molluscoidea  either  secrete  a  calcareous  shell,  or  are  invested 
with  a  membranaceous  or  corneous  covering.  The  respiratory  organs  lie 
anterior  to  the  mouth,  and  are  in  the  form  of  tentacles  or  fleshy  spiral 
appendages.  The  mouth  conducts  into  a  closed  alimentary  canal.  The 
nervous  system  is  highly  organised,  and  proceeds  from  a  central  ganglion, 
situated  in  most  cases  between  the  mouth  and  the  anus.  Reproduction  is 
either  sexual  or,  in  Bryozoa,  also  takes  place  by  budding.  The  ontogeny  of 
the  Molluscoidea  is  most  nearly  comparable  with  that  of  the  Annelids. 

All  of  the  Molluscoidea  are  water  inhabitants ;  the  Bryozoans  are  largely, 
and  the  Brachiopods  exclusively,  marine  forms. 

Olass  1.    BRYOZOA  Ehrenberg.i 

Small,  almost  always  composite  animals  forming  by  gemmation  variously  shaped 
colonies,  each  zooid  of  which  is  enclosed  in  a  membranaceous  or  calcareous  double- 

^  Literature :  d'Orhigny,  A.,  Paleontologie  francaise ;  Terrain  cretace,  vol.  v.,  1850-51. — Hagenow, 
F.,  Die  Bryozoen  der  Maestricher  Kreidebildung.  Cassel,  1851. — Haime,  J.,  Description  des 
brjozoaires  fossiles  de  la  formation  jurassique.  Mem.  Soc.  Geol.  de  France,  2nd  ser.  vol.  v.,  1854. 
• — Bush,  O.,  Catalogue  of  Marine  Polyzoa  in  the  Collection  of  the  British  Museum  (Parts  i.  and  ii., 
Cheilostomata),  1852-54.  (Part  iii.,  Cyclostomata),  1875. — Bush,  G.,  Monograph  of  the  fossil 
Polyzoa  of  the  Crag.  Palaeont.  Soc,  1859. — Oahh,  W.  M.,  and  Hörn,  G.  H.,  Monograph  of  the 
fossil  Polyzoa  of  the  Secondary  and  Tertiary  Formations  of  North  America.  Journ,  Acad.  Nat.  Sei. 
Philad.,  2nd  .ser.,  vol.  v.,  1862. — Beissel,  /.,  Ueber  die  Bryozoen  der  Aachener  Kreidebildung. 
Haarlem,  1865. — Reuss,  A.  E:,  Several  important  papers  in  Denkschr.  Akad.  Wiss.  Wien,  vols. 
xxiii.,  xxxiv.,  1863-74  ;  and  Palaeontographica,  vol.  xx.,  1872-74. — Manzoni,  A.,  Several  im- 
portant contributions  on  Tertiary  Bryozoans  in  Denkschr.  Akad.  Wiss.  Wien,  1869-78,  vols, 
xxix.-xxxviii.  —  Waters,  W.  A.,  Numerous  papers  on  Tertiary  and  Recent  Bryozoa  in  Ann.  and 
Mag.  Nat.  Hist.  and  Quar.  Journ.  Geol.  Soc,  1879-92. — Hincks,  T.,  History  of  the  British  Marine 
Polyzoa,  2  vols.,  1880.  —  Vine,  G.  R.,  Reports  on  fossil  Polyzoa.  British  Assoc.  Reports,  1881-85. 
—  Ulrich,  E.  0.,  American  Palaeozoic  Bryozoa.  Journ.  Cincinnati  Soc.  Nat.  Hist.,  v.-vii.,  1882-84. 
— Busk,  G.,  Report  on  Polyzoa.  Scient.  Results  Challenger  Exped.,  Zoology,  vols.  x.  and  xvii., 
1884-86. — Hall,  J.,  Lower  Helderberg,  Corniferous,  and  Hamilton  Bryozoa  (Palaeont.  N.Y.,  vol. 
vi.),  1886.  —  Ulrich,  E.  0.,  Palaeozoic  Bryozoa.  Geol.  Survey  Illinois,  vol.  viii.,  1890.  —  Ulrich, 
E.  0.,  Lower  Silurian  Bryozoa.     Geol.  Survey  Minnesota,  Final  Report,  vol.  iii.,  1892. — Gami,  F., 

314 


CLASS  I  BRYOZOA  315 

walled  sac  {zocedum),  and  possesses  typically  a  freely  suspended  alimentary  canal 
with  mouth  and  anns.  Mouth  surrounded  by  a  crown  of  hollow,  slender,  ciliated 
tentacles  arranged  in  the  form  of  a  circle  or  crescent.      Usually  hermaphroditic. 

Tlie  Biyozoa  resemble  certain  Corals  (Tabulata)  and  Hydrozoans  in  their 
external  configuration,  but  differ  from  tbem  radically  in  the  possession  of  a  distinct 
body  cavity,  a  closed  alimentary  canal,  a  highly  developed  nervous  System,  and 
delicate  respiratory  tentacles  siirroimding  tbe  moutb.  With  the  exception  of  the 
solitary  geniis  Loxosoma,  all  Bryozoans  live  associated  in  colonies  or  zoaria,  of  greater  or 
less  extent,  and  of  either  calcareoiis,  corneous  or  membranaceous  composition.  These 
colonies,  which  are  formed  by  frequently  repeated  gemmation,  present  a  multitudinous 
variety  of  form,  habit  and  structure.  Sometimes  they  grow  into  plant-like  tufts, 
composed  of  a  series  of  cells  variously  linked  together ;  very  commonly  they  spread 
over  Shells  and  other  foreign  bodies,  forming  delicate  interwoven  threads,  crusts  of 
exquisite  pattern,  or  hemispherical,  globular  or  nodular  masses  of  considerable  size ; 
often  they  rise  into  branching  stems,  and  fronds  of  varying  width  ;  and  at  other  times 
the  cell-bearing  branches  form  most  regulär  and  beautiful  open-meshed  lace-work. 

Each  zooid  or  polypide  is  enclosed  in  a  separate  Chamber  (zooscium)  of  either 
utricular  or  more  or  less  tubulär  form.  Occasionally  the  zooecia  are  quite  distinct 
from  their  neighboui's ;  more  commonly,  however,  intercommunication  is  effected, 
either  by  means  of  niinute  "  connecting  foramina "  piercing  the  Chamber  walls,  or 
by  a  common  canal  to  which  all  the  zooids  are  attached.  A  true  coenenchyma, 
such  as  is  found  among  the  Coelenterates,  never  occurs,  and  coenenchymal  gemmation 
is  accordingly  unknown  ;  but  a  somewhat  similar  "  vesicular  tissue  "  not  infrequently 
occupies  the  interzooecial  spaces  which  have  resulted  from  the  erection  of  the  zocecial 
tubes. 

Such  vesicular  tissue  occurs  constantly  in  the  Fistuliporidae  and  Cystodictyonidae,  and  in 
the  latter  the  primary,  or  even  the  prostrate  cells,  are  not  entirely  contiguous.  The  upper 
walls  of  the  vesicles,  at  least,  are  abundantly  perforated  ;  and  when  with  increasing  age  the 
vesicles  beconie  fiUed  with  a  secondary  deposit,  these  pores  are  not  obliterated,  but  continue  to 
pass  through  such  deposits  in  the  form  of  minute  vertical  tubes.  Precisely  the  same  kind  of 
tissue  occurs  in  other  Bryozoans,  notably  among  adult  colonies  of  certain  Fenestellidae,  in 
which  the  expanded  base  of  the  colony  is  largely  vesicular,  and  the  fenestrules  and  spaces 
between  the  carinae  of  the  branches  are  filled  with  vesicles  for  some  distance  up.  The  real 
purpose  of  this  tissue  is  to  support  the  zooecia  and  to  strengthen  the  zoarium. 

However  diverse  the  external  aspect  of  the  composite  structure,  the  small  animals 
themselves  conform  to  a  simple  and  quite  definite  type.  Briefly,  the  soft  parts  consist 
of  an  alimentary  canal,  in  which  three  distinct  regions,  an  Oesophagus,  stomach  and 
intestine,  are  recognisable.  This  is  enclosed  in  a  sac,  and  so  beut  upon  itself  that  its 
two  extremities,  or  openings,  approximate  ;  one  of  them,  the  oral,  being  either  entirely 
or  partially  surrounded  by  a  row  of  slender,  hollow  and  ciliated  tentacles,  which  serve 
for  respiration  and  for  sweeping  food  toward  the  mouth.  In  most  cases  the  anal 
opening  is  situated  without  the  ring  of  tentacles  (Ectoprocta),  rarely  within  the  same 
(Entoprocta).     Heart  and  vascular  system  are  wanting,  but  a  nervous  ganglion,  sending 

Nunierous  papers  on  Mesozoic  and  Cenozoic  Bryozoa  in  the  Bull.  See.  Gi^ol.,  France,  1897-1910. — 
Ulrich,  E.  0.,  Eocene  Bryozoa.  Eocene  volume,  Md.  Geol.  Surv.,  1901.— Ulrich,  E.  0.  and  Bassler, 
R.  S.,  Miocene  Bryozoa.  Miocene  volume,  Md.  Geol.  Surv.,  190\.— Ulrich,  E.  0.  and  Bassler,  R.  S., 
Revision  of  tlie  Paleozoic  Bryozoa.  Smith.  Mise.  Coli.,  vols.  xlv.-xlvii.,  190i.—Nickles,  J.  M.  and 
Bassler,  R.  S.,  Synopsis  of  American  fossil  Bryozoa.  Bull.  173,  U.S.  Geol.  Surv.,  1901.  (Contains 
a  list  of  all  bryozoan  literature  and  a  bibliograpliy  of  fossil  forms.) — Bassler,  R.  S.,  Bryozoan  Fauna 
of  the  Rochester  Shale.  Bull.  292,  U.S.  Geol.  Surv.,  1906.— Gregor]/,  J.  W.,  Cat.  Cretaceous 
Bryozoa  in  British  Museum,  2  vols.,  1899  and  1909.— Levinsen,  G.  M.  R.,  Cheilostomatous 
Bryozoa  (Recent).  Copenhagen,  1909.— Bassler,  R.  S.,  Early  Paleozoic  Bryozoa  of  the  Baltic 
Provinces.  Bull.  77,  U.S.  Nat.  Mus.,  1911.— Ilennig,  A.,  Gotlands  Silurische  Bryozoen.  Arkiv 
Zool.,  1908,  vol.  iv. — Canu,  F.,  Iconographie  des  bryozoaires  fossiles  de  I'Argentine.  Anal.  Mus. 
Nac.  Buenos  Ayres,  1909-11,  ser.  3,  vol.  x.—Lee,  O.  W.,  British  Carboniferous  Trepostomata. 
London,  1912. 


316  MOLLUSCOIDEA  phylum  v 

out  delicate  nerve  filaments  to  the  tentacles  and  Oesophagus,  lies  between  tlie  mouth 
and  anus.  The  upper  or  anterior  part  of  the  sac  is  generally  flexible  and  admits  of 
being  invaginated  by  the  action  of  numerous,  longitudinal  and  transverse  muscles, 
which  traverse  the  fluid -filled  visceral  cavity. 

Eeproductive  organs  are  developed  in  various  parts  of  the  cavity,  the  spermatozoa 
usually  in  the  lower,  the  ova  in  the  upper  portion.  The  ova  may  be  develoj)ed  in  a 
special  receptacle  (marswpium)  attached  to  the  zooecium,  or  in  an  inflation  of  the 
surface  of  the  zoarium  (gonocyst) ;  in  other  cases,  a  modified  zocecium  (gonoecium)  is  set 
apart  for  reproductive  functions.  The  general  term  omcium  or  ovicell  is  applicable  to 
all  of  these  structures. 

Many  Bryozoans  are  provided  with  appendicular  organs  known  as  avicularia  and 
vibracula  (Fig.  436).  Their  functions  are  somewhat  doubtful,  some  authors  regarding 
them  as  food-procuring  agents,  and  others  as  organs  of  defence. 
The  avicularia  may  be  immovably  attached  to  the  zocecium  ; 
but,  as  a  rule,  especially  among  Recent  forms,  they  are  peduncu- 
late,  and  capable  of  considerable  swaying  motion.  Often,  as  in 
Bugula  and  Bicellaria,  they  resemble  the  head  of  a  bird,  con- 
sisting  of  a  helmet-shaped  upper  piece,  with  a  formidable  hooked 
beak,  and  a  mandible  worked  by  powerful  muscles.  The  jaws 
open  and  close  with  a  perpetual  snapping  motion,  and  small 
organisms  or  other  foreign  particles  hapj^ening  in  their  way  are 
seized  and  held  with  a  tenacious  grasp.  The  vibracula  are 
flexible,  bristle-like  appendages,  generally  set  in  the  excavated 
summit  of  a  knob-like  elevation,  or  on  a  blunt  spine. 

The  avicularia  and  vibracula   are  themselves   incapable  of 

Fig.  436.  preservation,  but  their  former  presence  on  fossil  specimens  may 

Selenaria  maculata   be  generally  determined  by  the  slight  pore-like  excavations  in 

portL^o7up%f See   which  they  were  lodged.      The  tubulär  spines,  or  acanthopores, 

showing    a    vibracuium   which  are  of  such  common  occurrence  in  Paleozoic  Bryozoans, 

and  ovicell  (after  Busk).  .  ..i.  it_i.i  ,        n    •      -i         .         . 

were,  m  part  at  least,  probably  the  supports  of  similar  structures. 

The  term  lunarium  is  applied  to  a  more  or  less  thickened  portion  of  the  posterior 
wall  in  many  Paleozoic  Bryozoans,  which  is  curved  to  a  shorter  radius  and  usually 
projects  above  the  plane  of  the  zooecial  aperture.  Mesopores  are  angular  or  irregulär 
cells  occupying  interzocecial  Spaces  in  certain  Paleozoic  genera. 

Most  Bryozoans  are  attached,  either  by  the  greater  part  of  their  surface,  or  only 
basally,  to  extraneous  objects  ;  or  they  are  moored  to  the  bottom  by  root-like  appen- 
dages. In  many  forms  the  zoarium  is  regularly  jointed.  The  majori ty  of  genera 
inhabit  the  sea,  and  occur  in  all  zones  and  at  all  depths ;  only  a  few  genera  live  in 
fresh  water.     The  animals  subsist  chiefly  on  Diatoms,  Infusorians  and  larvae. 

Classification. — The  Classification  of  the  Bryozoans  remains  as  yet  in  an  unsatis- 
factory  condition.  D'Orbigny's  comprehensive  System  is  largely  artificial,  and 
although  numerous  modifications  and  improvements  have  been  suggested  by  later 
authors,  further  revision  has  still  to  be  undertaken. 

Lankester  divides  the  class  into  two  very  unequal  subclasses  as  foUows  :  (1) 
Holobranchia,  in  which  the  lophophore  or  row  of  tentacles  is  unbroken,  and  either 
circular  or  horse-shoe  shaped  ;  and  (2)  Pterobranchia,  containing  the  single  genus 
Rhahdopleura,  which  has  the  lophophore  produced  on  either  side  into  a  plume-like 
process,  so  that  the  tentacles  form  a  discontinuous  series. 

A  more  modern  System  is  to  regard  Bryozoans  as  a  primary  group  or  phylum, 
which  is  divided  into  two  unequal  classes,  named  by  Nitsche,  Ectoprocta  and  Ento- 
procta,  according  as  the  lophophore  surrounds  the  mouth  only,  or  encloses  both  the 
oral  and  anal  orifices.  The  first  of  these  classes  contains  the  bulk  of  the  known 
Bryozoa.  Furthermore,  the  marine  forms,  and  practically  all  genera  capable  of  pre- 
servation in  the   fossil  State,  are   included   in   the  subclass  Gymnolaemata  Allman. 


CLASS  I 


BEYOZOA 


317 


Tliis  is  distinguished  from  the  remaining  subclass,  Phylactolaemata  AUman  (which 
includes  tlie  freshwater  forms),  by  the  complete  abortion  of  tlie  foot,  and  ]jy  the 
cii'ciüar  arrangement  of  tlie  tentacles. 

The  Mesozoic  and  Recent  marine  Gymnolaeniata  are  almost  universally  divided 
into  the  three  Orders  proposed  by  Busk  :  the  Cyclostomata,  Cheüostomata  and  Cteno- 
stomata.  To  these  Vine  has  added  a  fourth,  the  Cryptostomata,  and  Ulrich  a  fifth, 
the  Trepostomata ;  both  of  which  serve  mainly  for  the  reception  of  Paleozoic  forms. 

The  detailed  Classification  of  the  Mesozoic  and  Cenozoic  Bryozoa,  especially  of  the 
Cheilostomata,  is  less  settled  than  that  of  the  ancient  types.  This  nonconformity  is 
due  in  part  to  the  widely  different  views  prevailing  among  authors  as  to  the  relative 
value  of  the  various  characters  upon  which  the  groups  are  founded  ;  and  partly 
because  the  mode  of  growth  and  zoarial  characters  in  general  are  much  less  constant, 
and,  therefore,  less  reliable  than  is  the  case  among  Paleozoic  representatives  of  the 
group. 

Subclass  1.     GYMNOLAEMATA   AUman. 
Order  1.     CTENOSTOMATA   Busk. 


Zoüßcia  usually  isolated  and  developed  hy  hudding  from  the  internodes  of  a  distinct 
tubulär  stolon  or  stem.  Orifice  terminal,  with  an  operculum  of  setce.  Zoarium  horny  or 
memhranaceous.     Marsupia  wanting. 

All  of  the  known  Paleozoic  Ctenostomata  have  been  described  by  Ulrich  and  Bassler  in  their 
Revision  of  the  Paleozoic  Bryozoa,  to  which  the  student  is  referred  for  a  discussion  of  these 
peculiar  fossils.  Mesozoic  and  Cenozoic  Ctenostomatous  Bryozoa  are  apparently  rare  and  little 
study  has  been  put  upon  tliem.  In  the  Recent  seas,  the  order  Ctenostomata  is  specifically  the 
least  represented  group  of  Bryozoa,  although  some  of  the  species  are  quite  abundant  and 
widespread. 

/)     ^ 
Family  1.   Rhopalonariidae 

Nickles  and  Bassler. 

Fusiform  segments  arranged 
in  a  more  or  less  pinnate 
manner,  impressed  or  almost 
emhedded  in  the  host. 

Rhopalonaria  Ulr.  (Fig. 
437,  G).  Ordovician  to  Lower 
Carboniferous. 

?  Terebripora  d'Orb.  Ter- 
tiary  and  Recent. 

Family  2.     Vinellidae 
Ulrich  and  Bassler. 

Creeping  hase  of  zoarium 
of  simple  or  locally  jointed, 
delicate,    tubulär    threads    ar- 


Fio.  437. 
Allonema  fusiforme  (N.  and  E.),  6/1. 


_         _  _  B,C,  Vlnella  repens  Ulr.,  2/3 

ranged' either  without  order  or  ^^^^'""Ti-^Ki^^^^ 

^     ,.  .  ,         and  B.,  6/1.     F,  Hcteronema  capiUareJJ.  and  B.,  ^/i.    G,  RhojKilonana 

proceeding    from    more    or     less    «enuis  U.  and  ß.,  6/i(after  Ulrich  and  Bassler). 

deßnitely  marked  centres.     In- 
ternodes with  a  Single  row  of  pores  or,  in  one  genus,  closely  punctate  ;  zooecia  unknown. 


Vinella  Ulrich  (Fig.  437,  5,  0).     Zoarium  of  very  slender  parasitic  tubulär  threads 


318  MOLLUSCOIDEA— BRYOZOA  phylüm  v 

or  stolons  arranged  radially ;  surface  with  a  single  row  of  pores.  Ordovician  to 
Lower  Carboniferous. 

Heteronema  Ulr.  and  B,  (Fig.  437,  F).  Zoaria  as  in  Vinella  but  threads  are  with- 
out  radial  arrangement.     Ordovician  to  Upper  Carboniferous, 

Allonema  Ulr.  and  B.  (Fig.  437,  A).  Zoaria  composed  of  distinct,  minutely 
punctate  vesicles  or  connected  internodes.     Silurian  to  Lower  Carboniferous. 

?  Ptychocladia  Ulr.  and  B.     Upper  Carboniferous. 

Family  3.     Ascodictyonidae    Ulrich. 

Zoaria  parasitic,  of  pyriform  porous  vesicles  arranged  in  radial  Clusters,  or  isolated 
and  connected  hy  delicate  hollow  threads. 

Ascodictyon  Nich.  and  Etil.  (Fig.  437,  D,  E).     Silurian  to  Lower  Carboniferous. 

Order  2.     CYCLOSTOMATA   Busk. 

{Bryozoaires  centrifugine's  d'Orbigny  p.p.) 

Zocecia  very  simple,  cylin^rical,  calcareous,  tubulär,  usually  without  transverse  parti- 
tions  ;  the  orifices  piain,  inoperculate,  not  contracted,  occasionally  expanded ;  walls  thin, 
minutely  porous;  apertural  portion- of  zooecial  tuhes  more  or  less  raised,  hent  outwards, 
free  or  in  bundles  ;  the  interspaces  with  or  without  solid  or  tubulär  strengthening  deposits. 
Marsupia  and  appendicular  organs  wanting.  Ocecium  a  large  cell  set  apart  for  repro- 
ductive  functions,  or  a  mere  inßation  of  the  zoarial  surface. 

The  families  and  genera  of  tliis  order  are  founded  almost  entirely  upon  the  form  of  the 
zoarium,  and  the  arrangement  of  the  zocecia.  The  presence  or  absence  of  interstitial  or 
accessory  cells  and  vesicular  tissue  (all  strengthening  deposits)  is  also  an  iiiiportant  character, 

For  many  years  it  was  customary  to  regard  all  Paleozoic  Bryozoans  as  Cyclostomata,  but 
the  labours  of  Ulrich  and  Vine  have  clearly  demonstrated  the  fallacy  of  such  an  assumption. 
The  families  Ceramoporidae  and  Fistuliporidae,  often  regarded  as  Trepostomata  or  ^'Ifonticuli- 
poroids,"  aivereferred  tothe  Cyclostomata  because  they  agree  with  its  most  typical  members  in 
having  amalgamated  and  minutely  porous  walls.  In  1890  Ulrich  discovered  ovicells  in  certain 
genera  of  the  Fistuliporidae,  while  more  recently  Bassler  lias  shown  the  occurrence  of  the 
same  structures  in  the  more  primitive  Ceramoporidae. 

Suborder  A.     TUBULIPORINA  Hagenow.     (Tubulata  Gregory). 

Zocecia  monomorphic,  of  elongated,  cylindrical  tubes  grouped  into  bundles,  sheets  or 
linear  series.  The  Tubuliporina  comprise  the  typical  Cyclostomata  and  in  all  probability 
give  rise  to  the  other  suborders. 

Family  1.     Orisiidae  Busk. 

Zoaria  dendroid,  attached  by  radical  tubes  and  composed  of  segments  united  by  corneous 
joints.     Zocecia  tubulär,  disposed  in  single  or  double  series. 

Grisia  Lamx.  {Grisidia  Jolinst. ;  Filicrisia  d'Orb.).      Zoaria  more  or  less  distinctly 
articulated,  the  zooecia  in  a  single  or  in  two  alternating  series.     Cretaceous  to  Recent. 
?  Unicrisia  d'Orb.     Cretaceous. 

Family  2.     Diastoporidae  Busk  (emend.). 

Zoaria  adnate,  adhering  by  the  entire  base  or  only  at  the  centre,  at  other  times  rising 
into  bifoliate  leaves  or  hollow  stems.  Zooecia  tubulär,  the  aperture  salient,  rounded,  never 
clustered.  Interstitial  cells  wanting.  Ovicells  mere  irregulär  inflations  of  the  surface  of 
the  zoarium,  with  one  or  more  openings.     Ordovician  to  Recent. 


ORDER  II 


CYCLOSTOMATA 


319 


Stomatopora  Bronn  {Alecto  Lamx.  non  Leach)  (Fig.  438).     Zoaria  delicate,  adnate, 
dicliotomously  brancliing.     Zooccia  sub-tubular  or  elongate-ovate,  arranged  in  a  single 


Fio.  438. 


Stomatopora  dichotoma  (Lamx.). 
GreatOolite;  Ranville,  Calvados. 
A,  Zoarium,  i/i.  B,  same,  en- 
larged. 


Fig.  439. 


A,  Corynotrypa  delicatula  (James).  Utica  Group  ;  Ciiicinnati,  Ohio. 
Zooecia,  lö/i.  B,  C.  inflata  (Hall).  Lorraine  Group ;  Cincinnati,  ö/j. 
C,  Prohoscina  frondosa  Nich.  Lorraine  Group  ;  Cincinnati,  Ohio.  Portion 
of  a  large  zoarium,  i2/j  (after  Ulrich). 


series ;  apertures  siib-terminal,  iisually  smaller  than  the  width  of  the  cell.  Ordovician, 
Jura,  Cretaceous,  Tertiary  and  Recent. 

Corynotrypa  Bassler  {ßtomatopora  in  part,  auct.)  (Fig.  439,  A,  B).  Zoarium 
unilinear,  adnate,  witb  short  to  elongate,  clavate  zooecia.     Ordovician  to  Devonian. 

Prohoscina  Audouin  (Fig.  439,  C).  Like  Stomatopora  but  zocecia  arranged  in  two 
or  more  series.     Ordovician,  Mesozoic  to  iRecent. 

Berenicea  Lamx,  {Diastopora  Busk,  non  Lamx.)  (Fig.  440).  Zoaria  forming  tbin, 
discoid,  flabellate  or  irregulär  crusts  upon  foreign  bodies.  Zooecia  arranged  in 
irregularly  alternating  lines.  Rare  in  Ordovician  and  Silurian,  very  abundant  in 
Jura  and  Cretaceous,  less  frequent  in  Tertiary  and  Recent, 


Berenicea  diluviana  Lamx.  Great  Oolite  ; 
Ranville,  Calvados.  A,  Young  expansiou, 
Vi.    B,  same,  enlarged  (after  Haime). 


Fig.  441, 

Diastopora  foUticea  (Lamx.).  Great  Oolite ; 
Ranville,  Calvados.  A,  Fragment  of  zoarium, 
Vi-     B,  Enlarged  portion  of  same. 


Discosparsa  d'Orb.  Differs  from  Berenicea  in  having  obconical  or  cup-shaped 
zoaria,  attaclied  by  centre  of  the  base  only.     Cretaceous  and  Tertiary. 

Filisparsa  d'Orb.  Zoarium  ramose,  brancbes  compressed  dorso-frontally;  apertures 
irregularly  disposed,     Cretaceous  to  Recent. 

Diastopora  Lamx.  {Mesenteripora  Blv.)  (Fig.  441).  Like  Berenicea^  except  that 
the  zoarium  rises  into  broad,  simple  or  convoluted  leaves,  composed  of  two  layers  of 


320 


MOLLUSCOIDEA— BRYOZOA 


PHYLÜM  V 


zocßcia  grown  back  to  back.  Very  abundant  in  the  Jura,  less  common  in  Cretaceous 
and  Tertiaiy. 

Bidiastopora  d'Orb.  Like  Diastopora,  but  the  zoaria  forming  only  narrow,  parallel- 
edged  brancbes.     Cretaceous. 

ReptomuUisparsa,  Cellulipora  and  Filicrisina  d'Orb.     Cretaceous. 

Diastoporina  Ulrich.  Ordovician.  Heder ella  and  Hernodia  Hall ;  and  Reptaria 
Rolle.     Devonian. 


Family  3.     Idmoneidae  Busk. 

Zoaria  forming  free  or  adnate,  variously  compressed  hranches.  Zocßcial  apertures 
rounded,  more  or  less  elevated,  usually  arranged  in  transverse  rows  on  two  faces  of  the 
hranches  ;  sometimes  the  two  faces  are  confluent.  Dorsal  surface  of  the  hranches  without 
zooecia,  hut  often  occupied  hy  numerous  small  tubulär  pores,  which  may  also  occur  near 
the  apertures.     Sac-like  ovicells  with  hut  a  single  opening.     Ordovician  to  Recent. 

Idmonea  Lamx.  Zoarium  adnate  with  apertures  opening  in  transverse  series. 
Jurassic  to  Recent. 

Grisina  d'Orb.  (Fig.  442).  Zoarium  erect,  simple  or  branching.  Brauches 
usually  triangulär,  two  of  the  faces  carrying  the  zooecial  apertures,  which  are  generally 
arranged  in  alternating  transverse  series.     Jurassic  to  Recent. 

Bisidmonea  d'Orb.  Quadrate, 
simple  or  branching  stems,  bear- 
ing  zooecial  apertures  on  all  faces. 
Cretaceous, 

Retecava  d'Orb.  Zoaria  reti- 
culated ;  branches  greatly  com- 
pressed laterally ;  reverse  side 
occupied  by  an  axial  rod.  Cre- 
taceous. 

Bicrisina,  Bituhigera,  Repto- 
fascigera,  Semiclausa,  Sulcocava 
{Laterocava)  d'Orb. ;  and  Pergen- 
sella Gregory.     Cretaceous. 

Phalangella  Gray.  Creta- 
ceous to  Recent. 

Protocrisina  Ulr.  (Fig.  443). 
Narrow,  bifurcating  branches,  celluliferous  on  one  side  only.  Zocecia  sub- tubulär, 
with  prominent  circular  apertures  arranged  in  intersecting  diagonal  series.  Small 
pores,  apparently  communicating  with  interior  of  the  zocecia,  irregularly  distributed 
over  both  faces  of  the  branches.     Ordovician  and  Silurian. 


Fig.  442. 

Grisina  dorsata  Hagenow, 
Cretaceous;  Maastricht.    J,  Brauch,  nat. 
size.    B,  Upper,  and  C,  Lower  side,  highly 
magnifled. 


Uppermost 


Fig.  443. 

Protocrisina  exigua 
Ulrich.  Trenton 
Group;  Trenton, 
N.Y.  Branches  of  a 
large  expansion,  i^^/i. 


Family  4.     Entalophoridae    Reuss. 

Zoaria  ramöse ;  hranches  free,  suh-cylindrical,  with 
rounded  and  more  or  less  prominently  exserted  zooecial 
apertures  opening  on  all  sides.  (?)  Without  accessory  or 
interstitial  pores  of  any  kind.     Ordovician  to  Recent, 

Entalophora  Lamx.  {Glavisparsa  d'Orb. ;  Pergensia 
Walford)  (Fig.  444).  Zooecial  tubes  disposed  about  an 
imaginary  axis,  and  with  rounded,  more  or  less  prom- 
inent apertures.     Jurassic  to  Recent. 

Spiropora  Lamx.  (Pustulopora  and  Gricopora  Blain- 
ville)   (Fig.   445).      Like  the   preceding,  but  apertures   Plauen ,^SaxJny 


Fig.  444. 

Entalophora  vir- 
gula  Hagenow. 
Plänerkalk; 


Fig.  445. 


Spiropora  vcr- 
ticillata  Goldf. 
Upper  Cretace- 
ous ;  Maestricht 
(after  Hagenow). 


ORDER  II 


CYCLOSTOMATA 


321 


arranged  in  regulär,  spiral  or  transverse  linear  series,  and  closely  situated.  Zooecial 
tubes  disposed  about  a  definite  central  axis  or  axial  tube.     Jurassic  to  Kecent. 

Diploclema  Ulr,  Similar  to  Entalophora,  but  witli  branches  spreading  in  the 
same  plane,  slightly  conipressed,  and  divided  into  two  equal  parts  by  a  wavy  mesial 
lamina,      Silurian. 

Haplooßcia  Gregory.  Like  Spiropora,  but  distal  ends  of  zooccia  are  angular. 
Jurassic  and  Cretaceous. 

Mitoclema  Ulrich.  Ordovician.  Clonopora  Hall.  Devonian.  Peripora  d'Orb. 
Cretaceous. 

Rhipidopora  and  Glinopora  Marsson ;  Siphoniotyphlus  Lonsdale ;  Clypeina  Michelin ; 
Umhrellina  Roemer.     Cretaceous  and  Tertiary. 


Family  5.     Fasciporidae    d'Orbiguy  (emend.). 

Zooßcia  tubulär^  opening  in  Clusters  at  the 
(jrowing  extremities^  and  in  linear  or  quincuncial 
series  on  the  sides  of  the  lamelliform,  or  ohconical 
zoaria.     Äccessory  pores  wanting.     Cretaceous. 

Fascipora  d'Orl».  (Fasciporina  d'Orb.).  Zoaria 
conipressed,  sub-rainose  to  lanielliforni.  Aper- 
tures  arranged  quincuncially  or  somewliat  ir- 
regularly  on  both  sides,  and  on  the  more  or  less 
expanded  growing  extremities  of  the  branches 
and  laniellae.  The  lanielliform  species  resemble 
Diastopora,  but  are  without  a  mesial  lamina. 

Semifascipora  d'Orb.  (Fig.  446).  Zoaria  cup 
or  funnel-shaped,  with  only  the  outer  surface 
poriferous,  the  inner  covered  by  an  epitheca. 
Poriferous  face  thrown  into  vertical  ridges 
bearing  the  salient  tubulär  mouths  of  one  or 
more  rows  of  zooecia.     At  the  upper  edge  the  ridges  pass  into  large  Clusters  of  apertures. 

Conotuhigera  and  Serietuhigera  d'Orb.     Closely  related  to  the  preceding. 


Fia.  446. 

Semifasci'pora  variabilis  d'Orb.     Cretaceous  ; 
France.     Side  view  of  zoarium,  lO/j. 


Fig.  447. 

Fascirulijwra  incrassata  d'Orb.  Upper 
('retaceous  ;  Meudon,  near  Pari.s.  Terminal 
tVagnient,  mt.  size  and  enlarged  (after 
d'Orbigny). 


Family  6.     Fascigeridae  d'Orbigny. 

Zoarium  composed  of  bundles  of  long,  parallel 
zooecia  free  for  most  of  their  length,  with  the  aper- 
tures in  groups  at  the  ends  of  the  bundles. 

Fasciculipora  d'Orb.  (Fig.  447).  Zoarium  of 
long,  simple  or  divided  branches.  Jurassic  to 
Tertiary. 

Corymbopora  Michelin.  Like  Fasciculipora 
but  sides  of  branches  marked  by  numerous  pores. 
Cretaceous. 

Apsendesia  Lamx.  Zooecial  bundles  arise  from 
a  small  cup-shaped  disk.     Jurassic  and  Cretaceous. 

Discofascigera  d'Orb.  Cretaceous  and  Ter- 
tiary. 


Family  7.     Theonoidae    Busk. 

Zoarium  adnate  or  erect ;  zooecia  simple,  short,  open  tubes  with  apertures  confined  to 
crowded  bands  along  raised  ridges  or  on  the  edge  of  the  fronds. 

VOL.  I  Y 


322  MOLLUSCOIDEA— BRYOZOA  phylum  v 

Actino'pora    d'Orb,     (Pavotuhigera,    etc.,   d'Orb.)  (Figs.    448,    449).       Zoariiiin  an 


Fig.  448. 

Actinopora  diadema  (Goldfuss).  Upper 
Cretaceous  ;  Maestricht.  A,  Zoarium,  ^|■^.  B, 
Profile  of  same.     C,  Upper  surface,  enlarged. 


Fig.  449. 

Actinopora  disticha  (Hag.). 
Upper  Cretaceous ;  France. 
Upper  surface,  8/j. 


Theonoa  (?)i>aurantiuni  M.  Edw. 
broken  open  in  a  vertical  plane,  Vi- 
surface. 


adnate  disk  with  apertiires  opeiiing  on  ridges  radiating  from  a  central  depression. 
Cretaceous  to  Recent. 

MuUituhigera  d'Orb.     Zoarium  Compound,  tlie  eleraents  structurally  resembling 
confluent  Actinoporae.     Cretaceous. 

llieonoa   Lamx.   {Tilesia   Lanix.  ;    Phyllofrancia    Marsson)   (Fig.  450).       Zoarium 

massive  or  frondose ;  surface 
crossed  by  broad  ridges  bear- 
ing  the  apertures.  Jurassic 
to  Tertiary. 

Patenaria,  Locularia 
Hamm ;  Retenoa  Gregory. 
Cretaceous. 

Family  8.     Osculiporidae 
Marsson. 

Zoarium  ramose,  cylindri- 
Crag;    Sussex.     A,   Zoariurn    cal  or  adnate  :  zooßcia  Simple, 

B,  Enlarged   portion   of  upper     ,  ■         j.       ji  -n     \i. 

^^  long,  m  bundles  with  the 
apertures  opening  in  Clusters 
on  the  surface  or  sides  of  the 
zoarium.. 

Filifascigera  d'Orb,  (Fig. 
451).  Zoarium  of  simple  or 
])ranclied,  creeping  stolons. 
Cretaceous  and  Tertiary. 

Lopholepis  Hagw.  Zoar- 
ium a  broad  incrusting 
sheet.      Cretaceous. 

Cyrtopora  Hagw.  Semi- 
cylindrical  stems  with  pro- 
minent Clusters  of  four  or 
more  zooecial  apertures  open- 
ing on  all  sides.  Cretaceous 
to  Recent. 

Osculipora    d'Orb.     (Fig. 

452).     Ramose,  with  Clusters 

obverse    face  of  the   branches. 


Fig.  451. 

Filifascigera  megaera 
Lonsd.  Upper  Cretace- 
ous ;  Vincentown,  N.J. 
Specimen  seen  from  above 
and  from  the  side,  i2/j 
(after  Ulrich). 

of    zooecia    opening 
Cretaceous. 


Fig.  45-2 


Osculipora  trun- 
cata  Hagw.  Up- 
per Cretaceous  ; 
Maestricht,  Hol- 
land. Fragment 
i/i,  and  enlarged 
(after  Ulrich). 


Fig.  4öb, 

Truncatula  repens 
Hagw.  Upper  Cretace- 
ous ;  Maestricht.  Lower 
and  Upper  sides  of  zoa- 
rium, enlarged  (after 
Hagenow). 


alternately   on  the  sides  of    the 


ORDER  II 


CYCLOSTOMATA 


323 


Truncatula    Hagw.    (Fig.  453).      Like    Osculipora,   biit    convex  sides  exliibiting 
iiuiuerons  pores  longitudinally  arranged.      Cretaceous. 

Homoeosolen  Loiisdale  {Supercytis,  Unicytis  d'Orb.).     Cretaceous. 

Discocytis  d'Orb.    (Pelagia  Mich.,  non  Lam.)  (Fig.   454).       Zoarium   cupuliform  ; 


Fig.  454. 

Discocytis  eucksü  d'Orb.     Upper  Cretaceous';  France.     Zoarium,  3/^,  and  three  views  of 
same  enlarged  (after  d'Orbigny). 

iil)per  surface  concave  with  radiating  ridges  having  apertures  at  their  outer  ends  ; 
ander  surface  poriferous.     Cretaceous. 

Gytis,  Badiofascigera,  Bicavea  d'Orb.     Cretaceous. 


Family  9.     Oeidae   d'Orbigny 

Zoaria  ramose,  bifoliate  or  uni-lamellate.  Zocecia  tubulär,  sub-equal,  their  walls 
at  first,  hut  thickening  gradually  toward  the  periphery,  where  the  cavity  suddenly 
dilates  in  such  manner  that  the  rounded  or  elliptical  aperture  lies  at  the  hottom  of  an 
hexagonal  depression.     Interstitial  cells  wanting.     Cretaceous. 

The  systematic  position  of  this  family  is  highly  problematical.  It  appears  to  have  certain 
affinities  with  the  Trepostomata,  but  its  removal  to  that  vicinity  is  hardly  feasible  until  a 
thorough  comparison  of  Paleozoic  and  Mesozoic  Bryozoans  shall  have  been  made. 

Semicea  d'Orb.  (Reptocea  d'Orb.  p.p.) ;  Discocea  Pergens. 


Fig.  455. 

Filiceavelata(E.agw.).     Upper  Cretaceous;  Maestri  cht,  Holland.     ^,  Branch,  Vi«     -B,  Surface 

of  sanie  enlarged.     C,  Vertical  section  (after  d'Orbigny). 

Gea  d'Orl).  Zoaria  forming  flattened  branches  or  broad  lamellae,  celhiliferous  on 
both  sides. 

Filicea  d'Orb.  {Laterocea  d'Orb.)  (Fig.  455).  Zoaria  erect,  with  sub-cylindrical 
branches  bearing  apertures  on  all  sides. 


324  MOLLUSCOIDEA— BRYOZOA  phylum  v 

Family  10.     Eleidae    d'Orbigny. 

Zoaria  ramose^  bifoliate  or  uni-lamellate.  Zooecial  tuhes  dilating  outvjardly,  with 
perforated  loalls.  Äpertures  lateral  and  siih-terminal^  many  of  them  closed  hy  ihin 
calcareous  films.  Vicarious  avicularia  and  seines  scattered  among  the  zooecia  in  some  of 
the  genera.     Cretaceous. 

The  members  of  this  family  difFer  widely  from  the  true  Cyclostomata,  and  the  presence  of 
avicularia  indicates  strong  affinities  with  the  Chilostomata,  The  Eleidae  undoubtedly 
represent  connecting  links  between  the  Cyclostomata  and  Chilostomata.  The  simplest  type 
of  Eleid  structure  is  found  in  the  Jurassic  geniis  Haploceeia  Gregory,  now  placed  in  the 
Entalophoridae,  in  which  the  aperture  is  subterminal,  instead  of  terminal,  and  is  constricted 
laterally. 

Reptelea  d'Orb.     Zoarium  adnate,  no  avicularia. 
Elea  d'Orb.     Zoarium  erect,  bifoliate  ;  no  avicularia. 

Meliceritites  Roemer  {Inversaria  Hagenow ;  Escharites  Roemer).  Cylindrical 
branching  stems  ;  avicularia  present. 

Foricula  d'Orb.     Like  Meliceritites  but  has  walls  pierced  by  pores. 
Semielea,  Nodelea  d'Orb.  ;  Reptoceritites  Gregory. 

Suborder  B.     CANCELLATA   Gregory. 

Zooßcia  monomorphic  with  walls  perforated  hy  cancelli,  that  is,  hy  roimded  or  elongate 
pore-like  cavities  different  from  the  usual  interspaces  or  mesopores. 

This  suborder  which  is  more  convenient  than  natural,  developed  in  early  Cretaceous 
times  from  certain  specialised  species  of  the  Idmoneidae. 

Family  11.     Horneridae    Hincks. 

Zoarium  erect  and  hranched  ;  zooecial  äpertures  only  on  the  ohverse  side  and  irregulär 
or  arranged  in  simple  lines.  Walls  of  zoarium  traversed  hy  fine  canals  luhich  appear 
at  the  surface  as  minute  pores.     Cretaceous  to  Recent. 

Hornera  Lamx. ;  Siphodictyum  Lonsdale ;  Hemicellaria  d'Orb. ;  Phormopora  Marsson. 

Family  12.     Petaloporidae    Gregory. 

Bamose  Cyclostomata  with  zooßcia  opening  on  all  sides  of  the  branches  and  walls 
perforated  by  numerous  mural  pore  structures,  somewhat  resembling  mesopores. 

Petalopora  Lonsdale  {Gavea  d'Orb.) ;  Sparsicavea  d'Orb.  ;  Gavaria  Hagenow ; 
Reptocavea  d'Orb.     Cretaceous  and  Tertiary. 

Suborder  C.     DACTYLETHRATA   Gregory. 

Cyclostomata  with  long  cylindrical  zomcia  separated  hy  dactylethra,  that  is,  by  short 
aborted  zocecia  closed  externally.     No  cancelli,  mesopores  or  avicularia. 

Family  13.     Olausidae    d'Orbigny. 

Zoarium  adnate  or  erect  with  the  zocecia  distributed  uniformly  and  separated  by 
circles  of  shallow  interstitial  cells  (dactylethrae)  closed  at  the  surface. 

Clausa  d'Orb.  {Claviclausa  d'Orb.).  Zoarium  erect  and  dendroid.  Cretaceous  and 
Tertiary. 


ORDER  II 


CYCLOSTOMATA 


325 


Gryptoglena  Marsson.     Zoariuin  adnate,  thick  and  unilaminar.     Cretaceous. 

Ditaxia  Hagvv.  {Polytaxia  Hamm).  Zoarium  erect,  lamellar  and  frondose. 
Cretaceous  and  Tertiary. 

Reticulipora  d'Orb.  {Retelea  d'Orb,).  Zoarium  reticulated  ;  branches  greatly 
compressed  laterally.     Cretaceous  to  Recent. 

BeptomiUticlausa,  Multiclausa  d'Orb.     Cretaceous. 

Terehellaria  Lamx.     Jurassic.     Zonopora  d'Orl).  {Spiroclausa  d'Orb.).     Cretaceous. 


Suborder  D.     CERIOPORINA   Hagenow  (emend.). 

Von  Hagenow  in  1851  maintained  the  Cerioporina  for  Ceriopora  and  allied  genera  but 

included  a  few  other  Cyclostomata.     Hamm  in  1881  recognised  the  same  name,  limiting  the 
group,  hovvever,  to  the  families  Cerioporidae  and  Radioporidae. 
The  name   is   thns   available    for   the  post-Paleozoic    Bryozoa 

agreeing   with   the   Trepostomata   in   having  well  -  developed  >JW3;.*^«.\a^^»f  *J'i^*"r--"'1i 

imniature  and  niatiire  regions  but  differing  in  the  amalgamated,  *'   "*  *           '  *   *    *•-*■-* 
minutely  porous  structure  of  their  walls. 


Family  14.     Radioporidae    Gregory. 

Zoaria  simple  or  composite,  discoid  or  massive,  adhering 
hy  more  or  less  of  the  under  surface.  Zooecial  apertures  on 
the  Upper  surface,  arranged  in  radial  series  separated  hy 
mesopores. 

Discocavea  d'Orb.  (Fig.  456).  Zoarium  of  simple 
discoid  groups,  witli  apertures  in  radial  uniserial  lines. 
Cretaceous  to  Recent. 

Lichenopora  Defrance  (Figs.  457,  458)  {Tecticavea  and 
Badiocavea  d'Orb.).  Like  Discocavea  but  apertures  ar- 
ranged in  elliptical  groups.     Jurassic  to  Recent. 


Fio.  456. 

Discocavea  pocillum  d'Orb.    Cre- 
taceous ;  France  (after  d'Orbigny). 


Fio.  457. 

Lichenopora  (?)  tubulifera  (Roemer). 
Oligocene ;  Astrupp,  Westphalia. 
A,  Zoarium,  Vi-  J^^  Cluster  of 
zoa'cial  ai)ertures,  enlarged. 


Lichenopora  stdlata  (Goldf.).  Pläner;  Plauen,  Saxony.  A, 
Zoarium,  Vi-  ß>  Same,  enlarged.  C,  Vertical  section  of  specimen 
from  Greensand  of  Essen, 

Stellocavea    d'Orb.      {Garinifer    Hamm).      Zoaria    discoidal,    the    upper   surface 
exhibiting   tlie   salient   edges   of   uumerous   radially   arranged    plates,   few   of   them 


326 


MOLLUSCOIDEA— BEYOZOA 


PHYLUM  V 


reaching  tlie  centre.  Zooecial  tubes  opening  on  tlie  two  opposite  sides  of  plates. 
Depressed  interspaces  occupied  by  interstitial  cells.     Cretaceous. 

Radiopora  d'Orb,  Zoariuni  massive  witli  zooecia  arranged  in  radial  series  separated 
by  wide  areas  of  mesopores.     Cretaceous. 

Actinotaxia  Hamm ;  Trochüiopora,  Tholopora  Gregory ;  SemimuUicavea,  Multi- 
cavea,  Pyricavea  d'Orb.     Cretaceous. 


Family  15.     Cerioporidae    Busk. 

Zoaria  multiform^  encriisting,  lamellar,  hulbous,  lohate,  digitate  or  ramose,  composed 
of  closely  arranged  thin-iualled  tubes.  The  lauer  sometimes  completely  separated  hy 
angular  interstitial  cells.  Walls  of  neighhouring  tubes  tJioroughly  amalgamated  and 
pierced  by  numerous  pores.     Trias  to  Recent. 

Under  this  family  are  grouped  the  genera  referred  by  Gregory  to  the  Cerioporidae  in 
which  mesopores  are  absent,  the  Heteroporidae  with  numerous  mesopores,  and  the  Zonatulidae 
with  mesopores  grouped  in  spiral  bands  or  rings.  The  internal  and  other  features  of  these 
three  families  are  identical,  and  it  is  believed  that  the  distribution  of  the  mesopores  is  in 
this  case  not  of  family  importance.  Gregory  assigns  these  three  families,  as  well  as  the 
Radioporidae,  to  the  Trepostomata,  but,  although  it  is  triie  that  they  resemble  the  earlier 
Order  in  some  features,  the  complete  amalgamation  and  porous  nature  of  their  walls  is 
exactly  the  same  as  in  typical  Cyclostomata. 

omulticava  d'Orh.     {Semicava  d'Orb.;  Reptocea  Keeping)  (Fig.  459).     Zoarium 

massive  or  branched,  multi- 
lamellar ;  zooecia  sliort,  meso- 
pores absent.     Cretaceous. 

Defranciopora  Hamm. 
Zoarium  of  superposed,  discoid 
colonies ;  mesopores  wanting. 
Cretaceous. 

Ceriopora  Goldfuss  (Oerio- 
cava  d'Orb.).  Zoarium  massive 
or  branched,  witli  long  zooecia 
and  no  mesopores.  Trias  to 
Recent. 

Heteropora  BlainvlUe  (Fig. 
460).  (Polytrema,  Grescis, 
Nodicrescis  d'Orb.).  Like  Ceriopora  but  with  numerous  mesopores.  Jurassic  to 
Recent. 

Biflabellaria  Pergens.  Like  Hetero- 
pora but  zoarium  bifoliate.     Cretaceous. 

Zonatula  Hamm.  Zoarium  dendroid 
with  spiral  or  annular  constrictions 
composed  of  mesopores.     Cretaceous. 

Plethopora  Hagw.  Like  Zonatula  but 
zooecia  open  in  knob-like  elevations. 
Cretaceous. 

Ghilopora  Haime.  Jurassic.  Multi- 
zonopora  d'Orb.  ;  Bivestis  Hamm  ;  Spar- 
sicytis  Filliozat.     Cretaceous. 


Fio.  459. 

ReptomuUicava  spongites  Goldf.     Greensand  ;  Essen.     A,  Zoarixim,  i/i 
B,  C,  Upper  and  lower  sides,  enlarged. 


Suborder  E. 


CERAMOPOROIDEA, 

nom.  nov. 


wmWmWsm 


Fig.  460. 


This  new  suborder  is  proposed  for  the    ^aiS^SfaTeÄS  "Ä  z'LaHu^T 'clveSi 

PaleOZOic  Bryozoans    included  in   tlie  two    section.     D,  Upper  siuface,  enlarj^ed. 


ORDER  IT 


CYCLOSTOMATA 


327 


families  Ceiamopoi idae  and  Fistuliporidae,  which  were  fornierly  assigned  to  tlie 
Trepostouiata  and  latterly  to  tlie  Cyclostoniata.  Tliey  agree  witli  tlie  Trepostoniata 
in  liaving  well-delined  ininiature  and  niature  zones  bnt  their  niinntely  poious  walls 
of  irregniarly  laniinated  tissiie,  large  mural  communication  pores  and  fmally,  ooccia 
typical  of  the  Cyclostoniata  seem  to  ally  tliem  more  closely  witli  tlie  latter  order. 
Tills  suborder  is  possibly  the  Paleozoic  representative  of  the  Cerioporina. 

Family  16.     Oeramoporidae    Ulrich. 

Zoaria  variable;  maculae  or  Clusters  of  mesopores  and  of  zocecia,  larger  than  the 
average,  occur  at  regulär  intervals.  Zocecial  apertures  usually  oblique,  of  sub-triangular, 
ovate  or  polygonal  form;  lunarium  present,  appearing  at  the  surface  as  a  prominent 
overarching  hood,  or  as  a  slightly  elevated  portion  of  the  margin,  of  crescentic  form 
with  the  ends  projecting  more  or  less  into  the  aperture.     Mesopores  or  interstitial  cells 


I  Hi 


Fio.  461. 
a,  Ceramopora  spongiosa  Bass.    Tangential  section,  20/j, 
showing  mural  pores,  2oyj.     d,  Crepipora  incra.tsata  Bass. 
(after  Bassler). 


h,  c,  Anolotichia  rhombiai  Bass.     Vertical  sections 
Vertical  section  with  ovicell-like  structures,  '^^/i 


generally  present,  always  irregulär,  and  usually  without  diaphragms.  A  few  horizontal 
diaphragms  often  present  in  the  zocecial  tubes.  Walls  minutely  porous,  composed  of 
intimately  connected  and  irregularly  laminated  tissue.  Large  mural  communication 
pores  sometimes  present.     Ordovician  to  Devonian. 

This  is  one  of  the  largest  and  most  iinportant  of  the  families  of  Paleozoic  Bryozoans,  and 
is  especially  common  in  the  Middle  and  Upper  Ordovician.     The 

earliest  forms  resemble  Berenicea  and  Apsendesia;   while  Ceramo-         -^Si^^SÄi^^Sli^l^  * 
porella,   Chiloporella,  and   especially  Favositella,  may   be   regarded         fWmamiWnl^im'i 
with  reasonable  confidence  as  the  progenitors  of  the  Fistuliporidae. 
At  any  rate  the  connection  between  the  two  families  is  so  intimate 
as  to  forbid  any  wide  Separation. 


Ceramopora  Hall  (Fig.  461,  a).  Discoidal,  free,  lamellate, 
massive  or  parasitic.  When  free,  under  surface  with  one  or 
more  layers  of  sniall  irregulär  cells.  Zooecia  opening  on  the 
Upper  surface,  large,  irregulär,  oblique,  imbricating,  and  radially 
arranged  about  the  depressed  centre.  Mesopores  irregulär,  short, 
numerous.  Large  communication  pores  in  walls  of  both  zooecia 
and  mesopores.      Ordovician  to  Devonian. 

Ceramoporella  Ulr.  (Fig.  462).     Zoaria  encrusting.     Zocecial 
tubes  short,  walls  thin,  apertures  more  or  less  oblique,  hooded, 
commonly  of  oval  sliape.      Mesopores  abundant,  often  completely  isolating  the  zocecia, 
Ordovician  and  Silurian. 


Fl(i.  4C2. 
Ceramoporella  dislincta 
Ulrich.  Lowor  Trenton, 
Minnesota.  Surface  of  para- 
sitic expansion,  i'-'/i  (after 
Ulrich). 


328 


MOLLUSCOIDEA— BRYOZOA 


PHYLÜM  V 


Goeloclema  Ulr.  (Fig.  463).  Hollow  branclies,  lined  internally  with  a  striated 
epitheca.  Zoojcia  as  in  Geramoporella,  biit  witli  thicker  walls.  Ordovician  and 
Silurian. 

Grejpi'pora  Ulr.  (Figs.  461,  d;  464).     Mesopores  almost  entirely  restricted  to  tlie 


FiC!.  463. 

Goeloclema  tren- 
tonensis  Ulr, 
Trentou ;  Minne- 
sota. Two  frag- 
ments,  ^/s,  and 
one  6/j. 


Fig.  464. 


Crepipora  perampla  Ulrich.  Lower  Trenton ;  Minnesota.  A,  Vertical 
section.  B,  Transverse  section,  7/j.  c,  Same,  i'i/x,  showing  lunaria.  D,  Sur- 
face  of  C..-simulans  Ulrich,  9/i  (after  Ulrich). 


maculae,  wliich  are  distributed  over  the  surface  as  niinutely  poroiis  elevations  or 
depressions.  Apertiires  very  slightly  oblique,  angiilar  or  sub-pyriform.  Liinarium 
well-defined  in  perfect  specimens,  best  shown  in  tangential  sections.  Ovicell-like 
bodies  known  in  one  species.     Ordovician  and  Silurian.  * 

Anolotichia  Ulr.  (Figs.  461,  &,  c;  465).     Zoaria  large,  ramose  or  digitale.    Lunarium 


AnoloticMaimpolita  Ulr.  Black  River  Shales  ;  Minnesota.  A,  Surface, 
6/i.  B,  Vertical  section,  6/j.  c,  Tangential  section,  12/^^  showing  tiibes 
of  lunarium.  IJ,  Tangential  section  of  A.  jmiderom  Ulr.,  from  the 
Richmond  formation  at  Wilmington,  Hl.,  showing  numerous  lunarial 
tubes  (after  Ulrich). 

sligbtly  elevated  at  tlie  surface,  traversed  internally  l:)y 
two  to  six  minute,  vertical,  closely  tabulated  tubes. 
Mural  communication  j)ores  present.  Ordovician  and 
Silurian. 

Ceramophylla  Ulr.  (Fig.  466).     Like  Ceranioporella 
but  zoarium  is  bifoliate,     Ordovician. 

Favositella  Ether.  and  Foord  {Bythotrypa  Ulr.)  (Fig. 
open  at  the  surface,  forming  interiorly  a  very  loose  vesicular  tissue. 
by  communication  pores.     Ordovician  and  Silurian. 

Ghiloporella  Ulr.     Ordovician. 

Scenellopora  Ulr.  Zoaria  simple,  pedunculate  ;  under  surface  witli  an  epitheca 
the  Upper  slightly  concave  and  celluliferous.  Zocccia  with  slightly  ol)lique,  sub- 
circular  apertures,  radially  arranged  on  the  summits  of  low  ridges.     Ordovician. 


Fig.  466. 

Ceramophylla  frondosa  Ulr.  Black 
River  Shales;  Minnesota.  A,  Zoa- 
rium, 2/3.  B^  Surface  of  same,  ß/j. 
6',  Two  zowcia  of  a  tangential  sec- 
tion, 12/1.  D,  Right  half  of  a  verti- 
cal section,  12/j  (after  Ulrich). 


467). 


Mesopores  numerous, 
Walls  pierced 


ORDER  II 


CYCLOSTOMATA 


329 


Spatürpora  Ulr.  (Fig.  468). 
Apertures  irregulär ; 
luiiariuni  scarcely  per- 
ceptible.  Mesoporen, 
wlieii  present,  cliiefly 
in  iiiaciilae.  Inter- 
spaces  often  witli  large 
bliint  spines  (?  acan- 
thopores).  Ordovician 
and  Silurian. 


Family  17.     Pistuli- 
poridae  Ulricli. 

Zoaria  massive, 
laminar  or  ramose,  the 
siirface  exhihiting  at  regulär  intervals 
"  maculae  "  or  "  monticules  "  com^ 
of   Clusters   of   vesicles    and   of   zooßcia 
slightly  larger  than  the  average.    Luna- 
rium  more  or  less  developed.     Zooecial 
tubes  never  angular,  thin-ivalled,  and 
ivith  horizontal  diaphragrifis ;  apertures 
closed  by  perforated  operculum.     Inter- 
spaces  occupied  by  vesicular  tissue.    Gell 
walls  minutely  porous.     Ordovician  to 
Perinian  ;  cliniax  in  Devonian. 


Zoaria  Ibrniing  thin  crusts,  especially  on  Orthoceras. 


Fig.  468. 

Spatiopora  aspera  Ulr.  Cincinnati  Group ;  Hamilton,  O. 
A,  Surface.  B,  Vertical  section.  C,  Tangential  section  ;  all 
i-«/i  (after  Ulrich). 


Waagen,  Wentzel  and  otliers  have 
referred  certain  merabers  of  tbis  family  to  the  Corals,  but  tbe  reasons  for  doing  so  rest 
obviously  upon  insufiicient  Observation.  Not  only  are  the  members  of  this  family 
derived  from  the  Ceramoporidae,  as  noted  above,  which  are  undoubted  Bryozoans, 
but  some  of  them  possess  ovicells,  tlius"  abundantly  proving  their  Bryozoan  nature. 

Fistulipora  M'Coy  (Didymopora  Ulr.  ;  Dybowskiella  Waag.  and  W.)  (Fig.  469). 
Zoaria  massive,  lamellate,  more 
rarely  ramose,  parasitic  or  free ; 
under  surface  with  wrinkled  epi- 
theca.  Zooecia  sub-radially  arranged 
about  the  surface  maculae ;  aper- 
tures ovoid,  sub-triangular  or 
pyriform,  according  to  the  degree 
in  which  the  lunarium  is  developed  ; 
interiorly   with  thin  walls,   and   a 

small  number  of  com plete  horizontal         .     ,.  ,.       .j,  .  , 

^  Fistuhpora     astnca    Ulrich, 

diapliragms.      Interspaces  smooth  or    Devonian    (Hamilton    Group); 

granulär,     occupied     internally    by   So?"  »/i?' ^''''^'  '^^""'"''^^ 

one  or  more  series  of  vesicles.    Rare 

in  the  Ordovician.      Common  from  Silmian  to  Lower  Car- 

boniferous  less  frequent  in  Goal  Measures  and  Permian. 

Cyclotrypa  Ulr.  (Fig.  470).  Like  Fistulipora,  but  the 
lunarium  obsolete,  and  zocecial  tubes  circular  in  transversa 
section.     Devonian . 

Eridopora  Ulr.  (Pileotrypa  Hall).  Zoaria  thin,  parasitic. 
Zooecia  with  oblique,  sub-triangular  or  ovoid  apertures. 
Lunarium  very  prominent.       Silurian  to  Goal  Measures. 


Fit;.  470. 
Cyclotrypa  communis  Ul- 
rich. Hamilton  ;  New  Buf- 
falo,  Iowa.  Vertical  and 
tangential  sections,  i*/i 
(alter  Ulrich). 


330 


MOLLUSCOIDEA— BRYOZOA 


PHYLUM  V 


Ghilotrypa  Ulr.     Zoaria  small,  ramose,  witli  a  narrow,  irregularly  contracting  and 
expanding  axial  tnbe.      Silurian  to  Lower  Carboniferous. 

2   Ulr.    (Fig.    471).      Zoaria   bifoliate.       Oblique    apertures   all  directed 


Meekopora  eximia  Ulr. 
from  the  side  and  edge, 
ovicell,  14/j  (after  Ulrich). 


Fio.  471. 

ehester  Group ;  Monroe  Co. 
=^4-     B,  Surface  of  same,  7/j. 


,  111.     A,  Specimen 
C,  Portion  showinjj; 


Strotopora  foveolata  Ulr. 
Keoknk  Group  ;  Bentons- 
port, Iowa.  Part  of  ex- 
pansion,  3/^,  and  surläce  of 
same,  7/^,  showing  zocecial 
apertures  and  broken  ovi- 
cells  (after  Ulrich). 


toward  the  distal  margin  of  the  zoarium  or  branch.  Liinarium  moderate  or  obsolete  ; 
diaphragms  numerous  and  often  recurved.  Ovicell  rather  large,  showing  at  the 
surface  as  a  convex  space  with  a  small  apical  opening, 
Silurian  to  Goal  Measures. 

Strotopora  Vir.  (Fig.  4.1 2).  Zoaria  ramose.  Large,  abruptly 
spreading  cells  (regarded  as  broken  ovicells),  distributed 
among  the  zooecia  on  ordinary  specimens;  when  perfectly  jDre- 
served  they  appear  as  strongly  convex  elevations  with  a  small 
opening  on  one  side.      Devonian  and  Lower  Carboniferous. 

Lichenotrypa  Ulr.  First  stages  like  Fistulipora,  after 
which  large  spines  and  irregulär  thin  walls  are  thrown  up 
about  the  apertures.      Devonian. 

Biiskopora  Ulr.  (Odontotrypa,  Glossotrypa  Hall)  (Fig. 
473).  Like  Fistulipora,  but  lunarium  remarkably  de- 
veloped,  projecting  ae  a  strong,  bidenticulate  process  nearly 
half  across  the  aperture.      Devonian. 

Pinacotrypa  Ulr.  ;  (?)  Botryllopora  Nich.  ;  Selenopora 
and  Favicella  Hall.  Devonian  ;  Hexagonella  W.  and  W. 
Devonian  and  Carboniferous. 


Fig.  473. 


Buskopora  dentata  Ulr. 
Devonian  (Onondaga  Group) ; 
Falls  of  the  Ohio.  Portions 
of  surface,  7/  and  14/,  (after 
Ulrich). 


Order  3.     TREPOSTOMATA  Ulrich.  ^ 

Zocecia  directly  superimposed  upon  one  another  so  as  to  form  long  tubes  intersected 
hy  straight  or  curved  partitions  (diaphragms  and  cystiphragms)  representing  the  Covers 

^  Two  regions  of  the  zocecial  tubes  are  distinguishable,  an  axial  or  "  immature "  region,  in 
which  the  diaphragms  are  remote,  the  walls  thin,  and  the  tubes  prismatic  through  contact  ;  and  a 
peripheral  or  "mature"  region,  in  which  the  tubes  bend  outward,  the  walls  are  thickened  and 
otherwise  modified,  the  transverse  partitions  rnore  abundant,  and  interzooecial  elements  (acanthopores, 
raesopores,  or  mere  strengtheuing  tissue)  are  developed. 

Waagen  and  Wentzel  aud  others  erroneously  assert  that  the  raesopores  and  acanthopores, 
occurring  so  commonly  in  the  Trepostomata,  are  young  zocecia  or  "  corallites. "  With  very  few 
exceptions,  these  really  very  different  elements  are  not  developed  until  the  zoarium  has  reached  the 
niature  stage,  in  which  new  zocecia  cease  to  be  given  off.  The  origiu  of  raesopores  {i.e.  all  cells 
occupying  interzocecial  spaces,  whether  invested  with  separate  walls  or  not)  is  due  to  the  same 
necessity  which  leads  to  the  distal  thickening  of  tlie  zocecial  tubes,  namely,  that  of  filling  up  space 
occasioned  by  the  growth  of  tubes  at  the  periphery,  and  by  the  change  in  the  direction  of  the  tubes, 

Sonic  of  the  tubes  provisionally  included  under  the  terra  raesopores,  like  some  of  the  acantho- 


I^y   ORDER  III 


TREPOSTOMATA 


331 


and  floors  of  successive  layers.  Zooecial  Covers  with  a  small,  usually  sub-central  orifice. 
Monticules  or  maculae  (containing  cells  differing  from  the  average  in  size,  or  in  hxiving 
their  apertures  elevoAed)  regiilarly  distributed  over  the  snrface. 

The  Trepostomata  include  the  greater  j^ortion  of  the  "  Monticuliporoids "  which 
by  some  writers,  particularly  Milne  Edwards  and  Haime,  were  regarded  as  Anthozoans. 
Nicholson  assigned  them  to  the  Octocoralla  becaiise  the  corallites  apparently  agreed 
with  Heliolites  in  their  microscopic  structure,  and  in  addition  were  snpposed  to  have 
iniperforate  walls  and  to  increase  by  intermural  gemmation  or  by  fission.  Ulrich 
has  insisted  upon  the  bryozoan  natiire  of  these  organisms,  and  has  published  niany 
facts  militating  against  Nicholson's  views.  Bassler  has  added  a  number  of  points 
confirmatory  of  their  bryozoan  affinities,  and  recently  Cumings  has  worked  out  the 
primitive  budding  stages  of  at  least  six  characteristic  genera.  He  finds  that  the 
budding  plan  of  Prasopora  and  allied  genera  is  precisely  the  same  as  in  typical  recent 
Bryozoa,  namely  that  it  consists  of  (1)  a  protoecium,  or  minute  circular  disk  ;  (2)  the 
ancestrula^  a  tubulär  zooGcium  of  the  type  seen  in  the  Cyclostomata ;  and  (3)  several 
primary  buds  arising  from  and  adjacent  to  the  ancestrula.  These  primitive  structures 
are  separated  from  the  rest  of  the  colony  by  a  considerable  thickening  of  their 
posterior  walls.  In  the  Corals,  development  from  the  planula  is  direct,  the  moment 
it  becomes  sedentary  and  therefore  the  presence  of  the  protcecium  alone  is  practically 
conclusive  as  to  the  systematic  position  of  the  Trepostomata  with  the  Bryozoa. 

Suborder  A.     AMALGAMATA   Ulrich  and  Bassler. 

Trepostomata  in  which  the  houndaries  of  adjacent  zooecia  are  ohscured  by  the  more  or 
less  complete  amalgamation  of  their  walls. 

Family  1.     Monticuliporidae    Nicholson  (emend,  Ulrich). 

Zoaria  multiform.  Zooecial  apertures  polygonal,  rounded  or  irregularly  petaloid. 
Mesopores  occasionally  wanting,  in  other  cases  numerous,  angular  and  crossed  by 
crowded    diaphragms.       Acanthopores  A  B 


always  present  in  the  mature  region. 
Ordovician  to  Devonian. 

The  incomplete,  curved,  transverse 
partitions,  termed  cystiphragms  by 
Ulrich,  are  the  principal  peculiarity  of 
this  family.  It  is  possible  that  tliey 
represent  ovicells,  but  their  significance 
can  only  be  conjeetured. 

Monticulipora  d'Orb.  (Fig.  474). 
Zoaria  incrusting  to  massive.     Zooecia 


Fig.  474. 


T  1         -^1  •       ^  1  1  MoniicuXipwaarhoreamT.    Trenton ;  Minnesota.     Vertical 

polygonal,    with    mmutely    granulöse  ^^^  ^n^  tangential  (ß)  sections,  i-«/i  (after  Ulrich). 

walls.       Cystiphragms    lining    both 

mature  and  immature  regions.     Mesopores  very  few  or  absent.     Acanthopores  small, 

granulöse,  more  or  less  numerous.     Ordovician  and  Silurian. 

Orbignyella  U.  and  B.     Ordovician  to  Devonian. 

Ätactoporella  Ulr.  (Fig.   475).     Zoaria  generally  encrusting.     Zooecia  with  veiy 

pores,  were  doubtless  occupied  by  specially  niodified  polypides,  which  probably  find  tlieir 
homologues  in  the  avicularia  and  vibracula  of  recent  Chilostomata.  But  niany  of  the  mesopores 
wliich  are  not  invested  by  separate  walls  are  to  be  regarded  as  mere  iuterspaces  between  the 
zooecial  tubes,  and  the  purpose  of  their  transverse  partitions  is  to  support  the  walls  of  the  latter,  as 
well  as  to  assist  intercomniunication  by  nieans  of  the  zoarial  parenchynial  cord. 


332 


MOLLUSCOIDEA— BRYOZOA 


PHYLÜM  V 


thin  inflected  walk,  the  apertiires  irregularly  petaloid.  Mesopores  niimerous,  frequently 
isolating  the  zooecia,  largely  filled  by  a  secondary  deposit.  Acanthopores  small  and 
very  niimerous.     Ordovician  and  Silurian. 

c 


Fio.  475. 


Atactaporella  typicalis  Ulr.     Black  River  Group  ;  Minnesota.     Surface  (.1),  tangential  (11), 
and  vertical  (C)  sections,  ^%  (after  Ulrich). 


Peronopora  Nicli. 

A 


Similar  to  the  preceding  but  zoaria  bifoliate,  and  zoa3cial  walls 
B  c  thicker,  not  inflected  by  the  acan- 

thopores, and  more  ring-like  in 
transverse  section.  Ordovician 
and  Silurian. 

Homotrypa    Ulr.    (Figs.    476, 

477).       Generally    raniose,    some- 

times  frondescent.      Zooecial  tiibes 

with  very  thin  and  finely  crenii- 

lated  walls,  and  remote  diaphragms 

in  the  axial  region.    Cystiphragms, 

isolated  or  in  series,  developed  in 

peripheral  region  only.    Apertures 

polygonal     or     sub  -  circiilar.       Mesopores 

iisually  few  and  restricted  to  the  maciilae. 

Acanthopores  generally  present.  Ordovician 

and  Silurian. 

Homotrypella  Ulr.  Like  Homotrypa  but 
mesopores  niimerous  and  cystiphragms 
usually  confined  to  the  early  part  of  the 
mature  region.  Ordovician  and  Silurian. 
Prasopora  Nich.  and  Eth.  (Fig.  478). 
Zoariiim  massive,  free.  Zooecial  tiibes 
prismatic     or     cylindrical,     thin  -  walled, 

A  B 


Structure  of  walls  and  parenchymal  cord  in  {A),  Homotrypa 
callosa  Ulr.,  35/j  ;  (B),  Stictoporella  frondifera  Ulr.,  »ö/^ ;  and  (C), 
Retepora  columnifera  Busk.     Recent,  60/^. 


Fig.  477. 

Homotrypa  subramosa  Ulr.  Black  River ;  Minnesota. 
A,  Surface. '  B,  Tangential  section.  C,  Vertical  sec- 
tion, 14/j.  X»,  H.  sejxtrata  Ulr.  Tangential  section, 
X  17. 


Fx(i.  478. 

Prasopora  simulatrix  Ulr.  Trenton  ;  Ken- 
tucky. A,  Transverse,  and  B,  Vertical  section, 
i4/i  (after  Ulrich). 


ORDP]R  III 


TREPOSTOMATA 


333 


separated  froni  one  aiiother  by  smaller  angiüar  mesopores,  and  contaiiiing  cystiphgrams. 
Acantliopores  usiially  pre- 
sent.       Ordovician      and 
Silurian. 

Mesotnjpa  Ulr.  (Fig. 
479).  Äspidopora  Ulricli. 
Ordovician  and  Silurian. 


Family  2.     Heterotry- 
pidae    Ulrich. 

Zoaria  frondescent, 
ramose,  massive  or  jjara- 
sitic.  Zocecia  polygonal, 
lüith  moderately  thin  lualls. 
Äcanthoporespresent,  some- 
times  of  large  size.  Diaphragma  numerous,  horizontal.  Cystiphragms  ivanting.  Ordo- 
vician to  Devonian. 

Dekayella  Ulr,    (Fig.  480).      Zoarium   always   frondescent,   mesopores  numerous, 


Fig.  479. 

Mesotrypa  infida  Ulr.    Black  River  Group  ;  Minnesota.     A,  Transverse 
section.    B,  C,  Vertical  sections,  i4/j  (after  Ulrich). 


!  I      T  /    >    '■  ■'' 

!/     1/  /  ,■'/ 


Fig.  480. 

Dehiyella  ohscura  (Ulr.).     Ordovician ;  Cincinnati,  Ohio. 
Tangential  and  vertical  sections,  i'i/i  (after  Ulrich). 


Fig.  481. 

Dekayia  aspera  Edw. 
and  H.  Ordovician ;  Cin- 
cinnati, Ohio.  Tangential 
section,  ^■^/i. 


and  acantliopores  of  two  sizes,  the  smaller  ones  tlie  more  abundant,  and  present 
only  in  the  peripheral  region.     Ordovician  and  Silurian. 

Heterotrypa  Nich.  Zoarium  frondescent,  and  acantliopores  all  of  uniform  size. 
Ordovician  and  Silurian. 

Dekayia  E.  and  H,  (Fig.  481).      Distinguished  from  Heterotrypa  by  the  absence  of 


Fig.  482. 

Stigmatella  foordi  (Nich.).  Ordovician  ;  Es- 
thonia.  A,  Tangential  section,  i^i.  B,  Vertical 
section,  22/j  (after  Bassler). 


K^'i'Kj'^'pi'^^ 


•^/?iS^lÄÄ 


Fig.  4S3. 

Ätactopora  maculata  Ulr.  Ordovician ;  Cincinnati, 
Ohio.  Transverse  and  vertical  sections,  n/i,  showing 
greater  part  of  a  solid  macula  (after  Ulrich). 


the  smaller  set  of  acanthopores,  and    lesser  number  of  mesopores  and  diaphragms. 
Ordovician. 

Petigopora  Ulrich.     Stigmatella  Ulr.  and   B,  (Fig.  482,  ^,  ^).     Ordovician  and 
Silurian. 


334 


MOLLUSCOIDEA— BRYOZOA 


PHYLÜM  V 


Ätactopora  Ulr.  (Fig.  483).  Zoaria  thiii,  growing  on  Orthoceras.  Zococial  apertures 
iiideiited  or  floriform,  accordiiig  to  position  of  the  veiy  niimerous  acanthopores.  Ratber 
large,  solid  elevations,  composed  of  abortive  cells,  and  completely  filled  by  calcareoiis 
deposit,  stud  tbe  surface  at  regulär  iiitervals.     Ordovician  and  Silurian. 

Leptotrypa  Ulr.     Ordovician.      Gyphotrypa  U.  and  B.     Ordovician  to  Devonian. 

Family  3.     Oonstellariidae    Ulrich. 

Zoaria  rawose,  frondescent,  laminar  or  encrusting.  Zooecial  tuhes  thin-walled  and 
prismatic  in  the  axial  region,  thicker  and  suh-cylindrical  in  the  peripheral ;  apertures 
rounded,  the  peristomes  slightly  elevated.  Meso'pores  angular,  ahundant,  generally 
isolating  the  ^ocecia,  at  intervals  gathered  into  usually  stellate  Clusters ;  closed  at  the 
surface,  the  closure  with  numerous  perforations.  True  acanthopores  wanting,  hut  small 
hollow  spines  or  granules  often  very  ahundant.  Diaphragms  straight  and  complete  in 
both  sets  of  tuhes.     Ordovician  and  Silurian. 

Gonstellaria    Dana    (Fig.    484).     Zoaria     growing    erect     from 


basal 


Fig.  484. 

Gonstellaria  florida  Vir.    Cincinnati,  Ohio.     J,  Vertical  section.    i>,  Tangential,  showing  aged  condition. 
C,  Average  tangential  section,  all  14/^,     j)^  Branch  of  the  natural  size  (after  Ulrich). 

expansion.  Surface  with  depressed  stellate  maculae,  the  Spaces  between  the  rays 
elevated  and  occupied  by  two  or  three  short  rows  or  Clusters  of  closely  approximated 
zooecial  apertures.  Mesopores  aggregated  in  the  maculae,  internally  with  gradually 
crowding  diaphragms.     Ordovician. 

Stellipora  Hall  (non  Hagw.  nee  Haime).  Differs  from  the  above  in  its  encrusting 
or  lamellate  habit,  and  in  having  only  mesopores  in  interspaces  between  the  raised 
zooecial  Clusters.     Ordovician. 

Nicholsonella  Ulr.  (Fig.  485,  A-G).     Laminar  expansions,  sometimes  giving   off 


Fio.  485. 
Nicholsonella  pulchra   Ulr.    Stones  River;  Tennessee.    A,  Surface,  7/j.    ß,  Vertical  section,  i4/^.     C,  Tan- 
gential sections  at  different  levels,  K/i  (after  Ulrich).     D,  Dianulites  fastigiatus  Bichw.     Silurian ;  Baltic 
Provinces.     Tangential  section,  14/^  (after  Bassler). 

flattened,   intertwining  branches   or  fronds.       Interzooecial  spaces    wide,  and   with 
numerous  mesopores,  which  have  thicker  and  more  numerous  diaphragms  than  the 


ORDER  III 


TBEPOSTOMATA 


335 


zooecial  tul)es  ;  tlie  spaces  becoiiie  filled  up  with  ag(',  l^y  a  calcareous  dei)osit,  rendfring 
walls  of  inesopores  unrecognisable.     Ordovician. 

Dianulites  Eicliwald  (Fig.  485,  D).  Zoaria  massive  ;  zooccia  and  mesopores  pris- 
matic,  tliin  walled  ;  walls  and  spines  with  miniite  granulöse  stnictures  as  in 
Nicholsonella.     Ordovician  and  Silurian. 

Tdiotrypa  Ulr.     Silurian  ;  North  America. 


Family  4.     Batostomellidae    Ulrich.  ^ 

Zoaria  usually  ramose,  occasionally  suh-lobate,  massive^  laminar  or  paradtic,  often 
consisting  of  superimposed  layers.  Zocecia  tvith  thick  walls  in  the  mature  region^  usually 
appearing  here  as  fused.  Diaphragms  horizontal,  those  in  peripheral  region  with  central 
Perforation.  Acanthopores  and  mesopores  usually  present;  the  latter  small,  often 
intermittent.     Ordovician  to  Permian.  , 

The  amalgamate  nature  of  the  zooecial  walls  is  most  marked  in  this  family. 

Bythopora  Miller  and  Dyer.  Small  branching  stems.  Apertures  oblique, 
attenuate  above.  Interspaces  canaliculate,  with  an  occasional  mesopore  or  none. 
Ordovician  and  Silurian. 

Gallotrypa  Hall.  Silurian  and  Devonian.  Eridotrypa  Ulrich.  Ordovician  to 
Devonian. 

Batostomella  Ulr.  {Geinitzella  W.  and  W. ;   Trematella  Hall)  (Fig.  486). 


Slender 


Fi(i,  486, 

Batostomella  splnulusa  Mir.  ehester  Group ;  Kentucky.  A,  B,  Vertical  sections,  one  with  and  the  other 
without  diaphragms,  i'i/i.  C,  Tangential  section,  l^/j.  j)^  Surface,  i^/^.  On  either  side  of  C  are  branches  of  the 
natural  size  (after  Ulrich). 

branches,  without  monticules.  Apertures  small,  circular  or  oval.  Interspaces 
rounded  or  canaliculate,  spinulose,  the  acanthopores  small  and  usually  very  numerous. 
Mesopores  small,  sub-circular.     Diaphragms  few.     Silurian  to  Permian. 

Stenopora  Lonsd.  (Fig.  487).  Zoaria  ramose,  sub-lobate,  massive,  laminar  or 
parasitic.  Zooecial  walls  periodically  thickened  in  the  mature  region.  Large 
acanthopores  at  many  of  the 
angles  between  the  zooecia. 
Mesopores  never  very  numerous, 
irreglüarly  distributed.  Dia- 
phragms sometimes  very  scarce, 
but  in  most  American  species 
abundant  in  the  peripheral 
region,  and  with  a  large  central 
Perforation.  Lower  Carboni- 
ferous  to  Permian, 

Anisotrypa  Ulr,  Divisional 
line  between  adjoining  tubes 
niorP  «bnmlv  rlpfiiipd  and  Ste.nopora  ame^^ana  V\r.  Keokiik  Group ;  Illinois.  Vertical  (X) 
more  snarply  aennea,  ana  ^^^  tangential  (B)  sections  showing  moniliform  walls  and  perforated 
periodic   SWellingS    of    the    walls    diaphragms,  l-»/^  (after  Ulrich), 


Fi.i.  487. 


336 


MOLLUSOOIDEA— BRYOZOA 


PHYLUM  V 


mucli  less  distinct  than  in  Stenopora.    Acaiitliopores  and  mesopores  absent ;  perforated 
diaphragms  numerous.     Lower  Carboniferous. 

Lioclema  Ulr.  (Fig.  488).       Ordovician  to  Goal    Measures.       Lioclemella  Foerste. 
Ordovician  and  Silurian.      Orbipora  Eichwald  (Fig.  489,  a,  b).     Ordovician. 


Fig.  488. 

Lioclema  foliata  Ulr.     Keokuk  Group  ;  Illinois.     A,  Vertical  section,  2i/j.     ß^  Tangential  section,  '•^o/i. 
C,  Portion  of  wall  and  acanthopore,  38/^.     D,  Interstitial  cell,|2^Vl  (alter  Ulrich). 


Fig.  489. 

a,  Orhipora  distincta  Eichw.     Section,  14/^.     i,^  o.  acanthopora  Bass.  i-^/i.     c,  cl,  Edhoniopora  communis  Bass. 
Ordovician  ;  Baltic  Provinces.    5/j  (alter  Bassler). 

Esthoniopora-    Bassler    (Fig.    489,  c,  d).      Zoariiim  massive ;    zooccia  with    senii- 
diaphragms  ;  no  mesopores  or  acanthopores.      Ordovician  ;  Esthonia. 

Suborder  B.     INTEGRATA   Ulrich  and  Bassler. 

Trepostomata  in  which  the  boundaries  of  adjoining  zooßcia  are  sharphj  defined  by  a 


Family  5.     Amplexoporidae    Ulrich. 

Zoaria  ramose,  discoidal,  massive  or  bifoliate.  Zocßcial  tubes  comjoaratively  simple, 
prismatic,  with  a  well-marked  divisional  line  between  adjoining  tubes.  Mesopores 
practically  absent,  but  small  abortive  cells  sometimes  found  among  the  large  zomcia 
forming  the  monticules.  Acanthopores  generally  abundant,  sometimes  wanting.  Ordovician 
to  Devonian. 

Amplexopora  Ulr.  Zoaria  ramose.  Acanthopores  always  present,  varying  m  size 
and  number.      Diaphragms  complete,  horizontal.      Ordovician  and  Silurian. 

Monotrypella  Ulr.  Like  the  above,  but  without  acanthopores.  Ordovician  to 
Devonian. 


lORDER  III 


TREPOSTOMATA 


337 


Rhombotrypa  U.  aiid  B.  Siluriaii.  Petalotrypa  and  IHscoirypa  Ulr.  Ordovician 
to  Devon  iaii. 

Family  6.      Halloporidae    Bassler  {Galloporidae  Ulricli). 

Zoaria  ramose,  suh-frondescent,  massive  or  discoidal.  Zooßcial  apertures  generally 
sub-circular  and  separated  more  or  less  completely  hy  angular  mesopores ;  at  other  times 
polygonal,  when  fhe  mesopores  are  few  or  wanting.  Zocecial  tuhes  thin-walled,  attaining 
their  füll  size  sloivly.     Acanthopores  wanting.      Ordovician  to  Devonian. 

In  this  faniily  the  proximal  ends  of  thetubes  arising  in  the  axial  or  "immature"  region 
liave  the  character  of  mesopores.     The  diaphragms  are  rather  closely  arranged  in  the  taperiiig 


Fig.  49U. 

HaZlopora  ramosa  (E.  and  H.).  Ordovician  (Cincinnati  Group);  Cincinnati,  Ohio.  A,  Zoarium,  natural 
size.  B,  Surface  slightly  magnified.  C,  Tangential  .section,  parallel  to  external  surface,  20/j.  j)^  Vertical 
section,  20/^.     ((^,<  and  D  alter  Nicholson.) 

proximal  end,  then  few  or  wanting  for  a  considerable  distance,  and  finally  become  crowded  in 
the  peripheral  or  mature  region. 

Hallopora  Bassler  {Gallopora  Hall  preoccupied)  (Figs.  490,  491).  Zoaria  usually 
ramose  and  biisliy,  tlie  branclies  often  anastomosing.  Apertures  closed  in  tlie  perfect 
State  by  perforated,  often  ornainented,  Covers,  which  are  left  behind,  as  growtli  proceeds, 


Fi(i.  491. 
A,  B,  Hallopora  eleqantula  (KaU).     Niagara  ;  Indiana.    Vertical  and  tangential  seetions,  "/j.    C,  D,  H.  imdti- 
tabulata  Ulr.     Lower  Trenton  ;  Minnesota.     C,  Vertical  section,  v/i.     D,  Surface  having  zooecia  open  (7/i),  and 
preserving  zoo?cial  covers  (i-*/i). 

to  form  floors  (diaphragms)  of  succeeding  layers.  Zocecial  tubes  of  two  sizes  in  the  axial 
region,  the  larger  ones  with  six  to  eight  sides,  the  smaller  set  four-  or  five-sided. 
Ordovician  to  Devonian. 

Halloporina,  nom.  nov.  (proposed  for  Calloporina  Ulrich  and  Bassler,  preoccupied 
by  Neviani  in  1895).  Like  Hallopora  but  diaphragms  wanting  and  walls  strongly 
crenulated.     Ordovician. 

Calloporella  Ulr.      Silurian  ;  North  America. 
VOL.  I  Z 


338 


MOLLUSCOIDEA— BRYOZOA 


PHYLUM  V 


Family  7.     Trematoporidae   Ulrich. 

Zoaria  ramose  or  encrusting.     Zocecial  tuhes  irregulär  in  the  axial  region,  their 
proximal  ends  with  diaphragms,  and  usually  constricted  where  the  latter  occur ;  walls 


Fio.  492. 

Tangential  sections  of  Batostoma  from  the  Black  River  Group  of  Minnesota,    A,  B.  fcrtile  Ulr.,  H/j. 
B,  Same,  var.   circulare,  l-J/j.     C,  B.  tvinchelli  var.  spinulosum  Ulr.,  38/^  (after  Ulrich). 

thickened  in  the  mature  region,  lines  of  contact  distinct.     Mesopores  generally  ahundant, 
usually  of  large  size,  their  apertures  closed.      Äcanthopores  more  or  less  ahundant. 

This  faraily  is  principally  distinguislied  from  the  Halloporidae  by  the  presence  of  äcantho- 
pores and  closed  mesopores.  The  Trematoporidae,  moreover,  have  a  general  looseness  and 
obscurity  of  structure  quite  unlike  that  of  any  otlier  Trepostomata. 


Batostoma 


492). 


Branches.  irregulär,  springing  from  a  large  basal 
expansion.  Zooocial  walls  of  varying 
thickness,  in  contact  only  at  limited 
points,  and  of  two  sizes  in  the  axial 
region.  Diaphragms  strong,  horizon- 
tal, complete.  Species  numerous  and 
mostly  very  abundant.  Ordovician 
and  Silurian. 

Hemiphragma    Ulr.    (Fig.     493). 
but   diaphragms   in 
tubes  incomplete. 
Ordovician  and  Silurian. 

Diplotrypa    Nich.,    emend.     Ulr. 

Hemiphragma  irrasum  mr.    Lower  Trenton ;  Minnesota.     /Tri:„   ACkA\       ^r^^r.\n   w,or,.,;,.^    ^^ ^^.,n,r 

A,  Vertical  section,  1^.    B,  Tangential,  H/^  (after  Ulrich).        (^  ^^'  ^^V'      /f^Oaria  massive,  generally 

free.      Zooccial    tubes     comparatively 


AV*       ^^~^^^ ^.^«Ä^W'" '      ■'-'ik^  Batostoma,    bi 
W^       kit^'M"\C^^       peripheral  part  of 


Fig.  493. 


Fig.  494. 

Diplotrypa  westoni  Ulr.     Richmond  Group  ;  Manitoba. 
Tangential  and  vertical  sections,  i4/j  (after  Ulrich). 


Fig.  495. 

Monotrypa  magna  Ulr.     Lower  Trenton  ;  Illinois, 
Transverse  and  ^'ertical  sections,  7/j  (after  Ulrich). 


ORDER  IV  CRYPTOSTOMATA  339 

large,  prismatic,  witli  horizontal  diapliragms.      Mesoporcs  few  to  niiineroiis,  varying 
in  size.      Ordovician  and  Siliirian. 

Monotrypa  Nicli.  {Phjchonema  Hall)  (Fig.  495).  Distin- 
gaislied  from  tlie  preceding  by  the  absence  of  mesopores  and 
fewer  diapliragms.      Ordovician  to  Devonian. 

Anaphragma  U.  and  B.  Ordovician  and  Silurian.  Ditto- 
pora  Dybowski  (Fig.  496).     Ordovician. 

Trematopora  Hall  (emend.  Ulr.) ;  Stromatotrypa  Ulr.  Or- 
dovician and  Silurian.  Fig.  49(5. 

Dittopora    colliculata 

^     ,  .  ^.^^....^«™^^,^^..  _  .  .       Eichw.       Ordovician  ;     Es- 

Order  4.        CRYPTOSTOMATA     Vine.  thonia.    Tangential  sections 

with  two  sets  of  acantho- 

Primitive    zooßcium  short^  pyriform   to  oblong,  quadrate  or  P^""*^^'     /i  ^^  ^^^'    *^^  ^^^' 

hexagonal,   sometimes    tubulär,    the    aperture    anterior.     In   the 

mature   colony   the  aperture  is  concealed,  occurring   at  the  hottom  of  a   tubulär   shaft 

("  Vestibüle "),   which    may  be  intersected  by   straight   diaphragms  or    hemisepta,   owing 

to  the  direct  super-imposition  of  layers  of  polypides.       Vestibulär  shaft  surrounded  by 

vesicular  tissue,  or  by  a  solid  calcareous  deposit ;  the  external  orifice  rounded.     Mar- 

supia  and  avicularia  wanting. 

The  Cryptostomata  diifer  from  the  Trepostomata  chiefly  in  that  the  "  immature  " 
region  (primitive  cell)  is  usually  much  sliorter  and  the  passage  to  the  mature  region 
more  abrupt. 

Some  of  the  Cryptostomata  are  ramose,  and  have  long,  thin-walled  prismatic 
tubes  in  the  axial  region,  with  or  without  diaphragms,  precisely  as  in  the  ramose 
Trepostomata  and  Cyclostomata ;  but  they  are  distinguished  from  the  latter  by  the 
presence  of  hemisepta,  similar  to  those  occurring  in  the  vestibule  of  E schar opora  and 
Phaenopora,  two  of  the  most  typical  genera  of  the  Cryptostomata.  That  these  axial 
tubes  are  not  of  primary  importance  is  shown  by  individuals  of  such  genera  as 
Goeloconus,  Bhombopora,  etc.,  in  which  a  second  layer  of  zooecia  has  grown  over  the 
first.  This  is  a  rare  condition,  and  is  probably  to  be  attributed  to  an  accidental 
Interruption  of  growth.  But,  where  observable,  it  is  to  be  noticed  that  the  inner 
extremities  of  the  zocecia  of  the  second  layer  are  not  drawn  out  into  tubes  like 
those  of  the  primary  set,  but  are  short,  and  in  all  essential  respects  like  those  of 
E  schar  opora.^ 

The  Cryptostomata  are  probably  nothing  more  than  Paleozoic  Cheilostomata, 
dlffering,  however,  from  the  typical  members  of  the  latter,  (1)  in  having  neither 
marsupia  nor  avicularia  ;  (2)  in  the  much  greater  deposit  of  calcareous  matter  upon 
the  front  of  the  zooecia,  thns  producing  the  vestibule ;  (3)  in  that  successive  layers  of 
polypides  are  often  developed,  one  directly  over  the  other,  in  a  continuous  tube ;  and 
(4)  in  that  whenever  a  zoarium  attains  an  uninterrupted  width  of  more  than  8  mm., 
it  exhibits  Clusters  of  cells  differing  more  or  less,  either  in  size  or  elevation,  from  the 
average  zooecia.  The  last  two  distinctions  are  suggestive  of  the  Trepostomata ;  and 
the  presence  of  a  vestibule  reminds  us  of  certain  Mesozoic  and  Recent  Cheilostomata, 
which  have  the  same  tubulär  Prolongation  of  the  aperture.  Thus,  the  Recent 
Adeonella  atlantica  Busk,  has  not  only  a  vestibule,  but  hemisepta  as  weil  Hemisepta 
are  never  found  in  the  Cyclostomata  and  Trepostomata,  but  are  a  very  common 
feature  of  the  Cryptostomata.  They  occur  at  the  bottom  of  the  vestibule,  and  doubt- 
less  served  as  supports  for  the  movable  operculum. 

^  The  almost  universal  practice  has  been  to  accept  the  presence  of  tubulär  zooecia  as  fully 
demonstrating  the  Cyclostoniatous  affinities  of  the  species  producing  tliem.  luvestigations,  how- 
ever, show  that  the  mere  form  of  the  zofficium  cannot  be  relied  upon  as  a  subordinal  cliai-acter  any 
more  than  is  the  presence  of  tabulae  in  a  tubulär  organism  a  certain  indication  of  an  Anthozoan. 


340 


MOLLUSCOIDEA— BRYOZOA 


PHYLUM  V 


Family  1.      Phylloporinidae    Ulrich. 

Zoaria  branching,  celluliferous  on  one  side  only,  the  other  side  striated ;  hranches 
free  or  anastomosing.  Zocßcia  more  or  less  tubulär,  often  with  diaphragms.  Hemisepfä 
wanting.'     Ordovician  to  Goal  Measures. 


a,  h,  Chasinatopora  suhlaxa  (Ulr.).    ö/j. 


Fio,  497. 
(',  d,  Traiisvers'e  aiid  longitudiiial  sections,  i^/^  (after  Ulrich). 


Ghasmatopora  Eicliwald  {Phylloporina  Ulr.)  (Fig.  497).  Brauches  irregularly 
anastomosing,  with  two  to  eight  ranges  of  zooecia  on  the  celluliferous  side.  Tabulated 
interstitial  spaces  generally  present,  closed  at  the  surface.     Ordovician  and  Silurian. 

Pseudohornera  Roemer  {Drymotrypa  Ulr.).  Ordovician  to  Devonian.  Chaino- 
dictyon  Foerste.     Goal  Measures. 


Family  2.     Fenestellidae    King. 

Zoaria  forming  reticulate  expansions,  celluliferous  on  one  side  only.  TJiey  are  com- 
posed  of  rigid  branches  united  by  regulär  non-poriferous  bars  (dissepiments) ;  or  may  be 
sinuous  and  anastomose  at  regulär  intervals  ;  or  may  remain  free.  Zocecia  enclosed  in 
a  calcareous  crust,  which  is  minutely  porous,  especially  on  the  non-celluliferous  side. 
Primitive  porlions  of  zocecia  oblong,  quadrate  or  hexagonal  in  outline.  Superior  hemi- 
septum  usually  present,  the  inferior  one  less  frequently.  Primary  orifice  anterior,  semi- 
elliptical,  truncated  behind.  External  apertures  rounded,  with  peristome,  and  covered, 
when  perfect,  by  centrally  perforated  closures.      Silurian  to  Permian. 

The  zoarial  characters  of  the  Fenestellidae  are  extremely  constaiit,  and  are  of  the  greatest 
systematic  importance.  The  zooecial  cavity  in  this  faniily  is  very  siniilar  to  that  of  the 
Ptilodictyonidae  and  Rhinidictyonidae  ;  and  the  same  is  also  true  of  both  tlie  primary  and 
external  orifices. 


Fic.  498. 

Fenestrlld  /r///u;-//(/s  Scliloth.     Permian  Dolomite  ;  Pcissniick,  Tlinrinj;ia.     .1,  Fra-inciiL  of/oarium,  natural  size. 

Ji,  Portion  Ol' external  surface,  sH^'htly  enlarged.     C,  Magnilied  iK)rtion  of  iiiterioi'  (teüuliferous  surface. 


ORDER  IV 


CRYPTOSTOMATA 


341 


Fenestella  Lonsd.  (Fenestrella  d'Orb.  ;  Actinostoma  Youiig)  (Fig.  498).  Zoaria 
Üabellate  or  fimnel-shaped,  poriferous  on  the  inner  side.  Branches  connected  at 
regulär  intervals  by  dissepiments.  Zooecia  in  two  rows,  separated  by  a  piain  or 
tuberculose  median  keel.     Silurian  to  Permian. 

Semicoscinium  Front  {Garinopora  Nich. ;  Cryptopora  ^ich.;  Gycloporina  Simpson). 
(Fig.  499,  e).  Zoaria  fimnel-shaped,  poriferous  on  the  outer  side.  Dissepiments 
Wide,  very  short,  the  branches  appearing  to  anastomose  on  the  non-poriferous  face, 
vvhere  the  fenestrules  are  sub-rhomboidal  or  rounded.  ZocEcia  in  two  ranges,  median 
keel  very  high  and  expanded  at  the  summit.      Silurian  and  Devonian. 

Fenestrapora  Hall.  Like  the  preceding,  except  that  the  reverse  of  the  zoarium 
and  the  expanded  summits  of  the  carinae  bear  large,  scattered  pores,  or  pits. 
Devonian. 


(i,  Archimedes  dlstans  Ulr. 
d,  Unitrypa  acaulis  Hall,     ö/ 


(afLer  Ulrich,  Hall,  and  Simpson). 


Fig.  499. 


l/l.     h,  Polypora  simulatrix  Ulr.     i/i  and  y/j. 
e,  Semicoscinium  interruptum  H.  and  S.     "/i. 


:,  Hemitrypa  proutana  Ulr.     S/j. 
/,  FenestraZia  compacta  Ulr.     ö/j 


Helicopora  Claypole  ;  Isotrypa,  Loculipora,  Unitrypa  Hall  (Fig.  499,  d).  Silurian 
and  Devonian. 

Hemünjpa  Phill.  (Fig.  499,  c).  Differs  from  Fenestella  in  having  a  reticulated 
superstructure,  wliose  meshes  correspond  in  position  and  number  with  the  zooecial 
apertures  in  the  branches  beneath.     Silurian  to  Lower  Carboniferous. 

Archimedes  Lesueur  (Fig.  499,  a).  Distinguished  from  Helicopora  by  its  solid 
central  axis.  As  a  rule,  the  fenestrated  expansion  is  broken  away,  leaving  only  the 
screw-like  axis.     Lower  Carboniferous. 

Lyropora  Hall.  Zoaria  flabellate,  the  fenestrated  portion  spread  between  the 
arms  of  a  non-celluliferous  U-  or  V-shaped  support ;  free  or  pedunculate  at  the  base. 
Zooecia  in  from  two  to  five  rows.     Lower  Carboniferous. 

Fenestralia  (Prout  F'ig.  499,  /).  Having  a  median  keel  as  in  Fenestella^  but  with 
four  ranges  of  zooecia  instead  of  two.     Lower  Carboniferous  (St.  Louis  Group). 

Polypora  M'Coy  {Protoretepora  Koninck)  (Fig.  499,  h).  Differs  from  Fenestella 
in  having  two  to  eight  rows  of  cells  on  a  brauch,  and  in  wanting  a  median  keel. 
The  latter  is  sometimes  represented  by  a  row  of  strong  tubercles.  Silurian  to 
Permian. 

Thamniscus  King.  Like  Polypora,  but  branches  bifurcating  more  freely,  and  with 
only  a  few  dissepiments  or  none.     Silurian  to  Permian. 

Phyllopora  King.     Zoaria  funnel-shaped,  celluliferous  on  the  outer  side,  and  con- 


l 


342  MOLLUSCOIDEA— BRYOZOA  phylüm  v 

sisting  of  anastomosing   branches,   which   form   a   regulär,   roimd-meshed   network. 
Zooccia  in  two  or  more  rows.     Devonian  to  Permian. 

Ptüoporella,  Ptüoporina  Hall.  Siliirian  and  Devonian.  Eeteporina  d'Orb. 
Devonian  and  Lower  Carboniferous.     Anastomopora  Simpson.     Devonian. 

Family  3.     Acanthocladiidae    Zittel. 

Zoaria  poriferous  on  one  side  only,  pinnate  or  forminy  fenestrated  expansions  ;  con- 
sisting  of  sträng,  central  stems  which  give  off  numerous,  smaller,  lateral  hranches  fr  am 
their  opposite  margins.  The  lateral  hranches  are  free  or  unite  with  those  of  the  next 
stem.  Non-poriferous  dissepiments  ahsent  Zooßcial  characters  mostly  as  in  the  Fene- 
stellidae.     Silurian  to  Permian. 

Pinnatopora  Vine.     {Glauconome  auct.,  non  Goldfuss)  (Fig.  500,  b,  c).       Zoaria 

small,  delicate,  with  short,  free,  lateral 

^                                        FSW^  branches  given  off  frequently  at  regulär 

Aji        '-.\  ,,                 ^A^*i^r  intervals.     Cells  in   two  rows,   one   on 

<^''^  M-'r  >'-,''-    Z  '                ^*^  ^^^^  ^^^^  ^^  ^  moderate   median  keel. 

pp'^  Silurian  to  Permian. 

/^^•|^p.....l  Septopora  Vroiit.     Zoaria  fenestrated, 

-i       ^(^lM  yr\  flabellate  or  leaf-like.    Primary  branches 

^  t>           \^^^  numerous,  increasiug  by  bifurcation  or 

j                           '  :^\^  j^.^  ^    f  Interpolation ;      the      lateral     branches 

^^^p^      ^   M/Q  uniting  with  those  of  adjacent    stems. 

^^^^             rj.'^m^  Reverse    usually  with    fine    Striae   and 

^                   %ti„-»r  scattered  dimorphic  pores.     Celluliferous 

Fig.  500.  side  with  two  rows  of  zooecia  arranged 

a,  Acanthociadia  fruticosa  uir.    i/i.   I&,  Pinnatopora  as  in  Pinnatopora.     Chester  Group  and 

tenuiramosa  Ulr.     V^.     c,  P.  vinei  Ulr.    i/i  and  9/i  (after    q^^^  Measures. 

Acanthociadia  King  (Fig.  500,  a). 
Like  Pinnatopora,  but  larger,  stronger,  and  with  three  or  more  ranges  of  cells.  Goal 
Measures  and  Permian. 

Synocladia  King.  Differs  from  Septopora  in  the  same  manner  as  the  preceding 
differs  from  Pinnatopora.     Permian. 

Ptilopora  M'Coy  {Dendricopora  Koninck).  Zoaria  pinnate,  the  central  brauch 
much  stronger  than  the  oblique  lateral  branches,  which  are  united  by  dissepiments. 
Zooecia  in  two  ranges.     Devonian  and  Lower  Carboniferous. 

Diploporaria  N.  and  B.  {Diplopora  Young).  Essentially  a  Pinnatopora  without 
lateral  branchlets.     Garboniferous. 

Family  4.     Arthrostylidae    Ulrich. 

Zoaria  articulated,  consisting  of  numerous  suh-cylindrical  segments  united  into  small 
pinnate  or  bushy  colonies,  or  of  continuous,  dichotomously  divided  hranches.  Zooecia  suh- 
tuhular,  more  or  less  oblique,  radially  arranged  ahout  a  central  axis,  and  opening  on  all 
sides  of  the  segments ;  or  one  side  may  he  non-celluliferous  and  longitudinally  striated. 
Ordovician  and  Silurian. 

Arthrostylus  Ulr.  (Fig.  501,  d,  e).  Zooecia  bushy,  dichotomously  branching,  the 
whole  consisting  of  numerous  exceedingly  slender,  equal,  subquadrate  segments, 
united  by  terminal  articulation.  Zooecia  usually  arranged  in  three  rows  between 
longitudinal  ridges  ;  the  fourth  face  with  lougitudinal  Striae  only.      Ordovician. 

Helopora  Hall  (Figs.  501,/;  502).  Like  the  precediug,  but  the  segments  are 
larger,  and  have  zooecial  apertures  on  all  sides.     Ordovician  and  Silurian. 


ORDER  IV 


CRYPTOSTOMATA 


343 


Sceptro^wra  Ulr.     Segments  short,  greatly  expanded  above,  celluliferous  all  aroimd. 
Ordovician  and  Silurian. 


U^ 


f.-  7\ 


m 


W-J 


a,  Arthroclema  bülingsi  Ulr.     2/3.     ^^ 


Fig.  501. 
A.  armatum  Ulr.    Segment,  12/j. 


c,  Nematojwra  conferta  Ulr.    6/^, 


d,  e,  Ärthrostylus  conjunctus  Ulr.    12/j.    /^  Helopora  harrisi  Ulr.     12/j  (after  Ulrich). 

Arthroclema  Bill.  (Fig.  501,  a,  b).  Segments  sub-cylindrical,  celluliferous  on  all 
sides,  arranged  pinnately.     Articulation  both  terminal  and  lateral.     Ordovician. 

Nematopora  Ulr.  (Fig.  501,  c).  Zoaria  very  slender, 
ramose,  continiious  above  the  pointed  basal  extremity.  Zooecia 
sub-tubular,  arranged  radially  about  one  or  two  minute  axial 
tubes.     Ordovician  and  Silurian. 

Glauconome  Goldf.  (Penniretepora  d'Orb.).  Zoarium  branch- 
ing  continuously  ;  reverse  side  non-celluliferous  ;  zooecia  as  in 
Nematopora.     Ordovician  and  Silurian. 

Family  5.     Rhabdomesontidae  Vine. 

Zoaria  ramose  or  simple,  not  articulated,  sometimes  with  a 
large  or  small  axial  tube,  and  generally  solid.  In  the  latter 
case  the  axial  region  is  occupied  by  thin-walled  primitive  tubes, 
with  or  without  diaphragms.  Hemisepta  usually  present,  but 
never  conspicuous.  External  zooßcial  apertures  oval  or  circular, 
regularly  arranged,  and  usually  at  the  bottom  of  a  rhombic  or 
hexagonal  sloping  area,  or  between  longitudinal  ridges.  Mesopores  absent.  Ordovician 
to  Permian. 

Rhombopora  Meek  (Fig.  503,  b).  Zoaria  slender,  ramose,  solid.  Zooccial  tubes 
witb  tbe  outer  or  vestibulär  region  thick-walled,  apertures  arranged  in  diagonal 
or  longitudinal  lines.  Strong  acanthopores  and  smaller  spines  generally  present. 
Ordovician  to  Permian. 

Bactropora  Hall.  Zoaria  simple  or  only  slightly  brancbed,  the  lower  extremity 
pointed.     Lower  Carboniferous-. 

Rhabdomeson  Young.  Differs  from  Rhombopora  only  in  having  a  slender  axial 
tube,  to  wbich  the  proximal  ends  of  the  zocEcia  are  attached.  Goal  Measures  and 
Permian. 

Goeloconus  Ulr.  (Fig.  503,  a).  Zoaria  simple,  hollow,  expanding  gradually  from 
the  striated  base ;  substance  thin.  Primitive  portion  of  zooecia  short,  with  well- 
developed  hemisepta.     Lower  Carboniferous. 


Fig.  502. 
Helopora   spiniformis   Ulr. 
Stones     River ;     Tennessee. 

A,  Vertical     section,     l^/i. 

B,  Segment,    l/i    and    l4/l 
(aft«r  Ulrich). 


344 


MOLLÜSCOIDEA— BEYOZOA 


PHYLUM  V 


Nemataxis  Hall. 

a 


Devoiiian.     Nematotrypa  Bassler.     Ordoviciaii.     Orthopora  Hall. 


f 


Fig.  603. 

a,  Coeloconus  rliomhicu»  Ulr.  Vi  and  surface  i^/i.     h,  Rhoinbopom  incrassata  Ulr.  i/^  and  ]«/i.    c,  StreUotrypa 
major  Ulr.  i/j  and  18/^.     d,  Acanthodema  conflucns  Ulr.  i/i  and  24/j  (after  Ulrich). 

Silurian   and   Devonian.     Hyphasmopora  Etlieridge.      Carboniteroiis.      Acanthodema 
Hall  (Fig.  503,  d).     Silurian  to  Lower  Carboniferous. 

Tropidopora  Hall.     Devonian.     Strehlotrypa  Ulricli  (Fig.  503,  c).     Devonian  and 
Lower  Carboniferous. 


Family  6.     Ptilodictyonidae  Ulrich. 

Zoaria  hifoliate,  composed  of  two  layers  of  zomcia  grown  together  back  to  back,  usualhj 
joined  at  hast  at  the  base,  and  forming  leaf-like  expansions,  or  compressed,  branching 
or  inosculating  stems.  Mesial  plates  ivühout  median  tubuli ;  hemisepta  usually  present. 
Inner  orifice  generally  semi-elliptical,  the  outer  more  rounded,  usually  ovate,  and 
surrounded  by  either  a  sloping  area  or  a  ring-like  peristome.  Vestibules  separated  by 
thick  walls.     Ordovician  to  Devonian. 

Ptilodictya  Lonsd.  (Heterodictya  Nich.).  Zoaria  lanceolate  or  falciform,  witli  a 
small  basal  expansion.  In  tlie  young  condition  the  zoariuni  consists  of  longitudinally 
arranged,  narrow,  oblong-quadrate  zocecia,  new  zooccia,  of  different  width  and  arrange- 


Fig.  504. 

a,  Esckaropora  angularis  Ulr.  Vi  and  surface  s/j.     h,  E.  subrecta  Ulr.  »/j.     c,  d,  Stirtoporella  cribrosa  Ulr.  Vi 
and  surface  i8/i.     Black  River  of  Minnesota  (after  Ulrich). 

ment,  being  added  subsequently  on  each  side.  In  the  vestibulär  or  outer  region  the 
walls  are  more  or  less  thickened,  solid,  and  with  a  double  row  of  exceedingly  minute 
dots.     Silurian  and  Devonian. 


ORDER  If 


CRYPTOSTOMATA 


'A  1 5 


Escharopora  Hall  (Nicholsonia  Waag.  and  Wentz)  (Fig.  504,  a,  h).  Like  Ptilodictya 
biit  apertiires  are  in  diagonally  intersecting  series.      Ordovician. 

Phaenopora  Hall.  Zoaria  as  in  Ptilodictya^  except  that  tliere  are  two  mesopores  in 
eacli  interspace  between  tlie  ends  of  tlie  zoa3cial  apertures.     Ordovician  and  Silurian. 

Ärthropora  Ulr.  Zoaria  bushy,  spreading  in  a  plane,  composed  of  numeroiis 
equal  segments.  Zooecial  apertures  elliptical,  surrounded  by  a  delicate  peristome. 
Interspaces  witb  one  or  more  threadlike  ridges,  varioiisly  disposed,  and  with  a  row  of 
minute  papillae.     Ordovician  and  Silurian. 

Graptodictya  Ulr.  Ordovician.  Clathropora  Hall.  Silurian.  Stictoporina  Hall. 
Devonian. 

Family  7.     Stictoporellidae  Nickles  and  Bassler. 

This  family  differs  froni  tlie  Ptilodictyonidae  mainly  in  that  tlie  zoarium  is  not 
articulated,  but  grows  upward  from,  and  is  continuous  with,  a  spreading  base. 

Stictoporella  Ulr.  (Fig.  504,  c,  d).  Zoaria  variously  formed,  wdth  elliptical 
apertures  placed  at  the  bottom  of  a  sloping  area.  Thick-walled  intabulated  mesopores 
occur  between  the  zocEcial  a])ertures  and  line  the  zoarial  margins.  Ordovician  and 
Silurian. 

Stictopora  Hall.  Ordovician.  Ptilotrypa  Ulrich.  Silurian.  Intrapora  Hall. 
Devonian  and  Lovver  Carboniferous.  Coscinella  Hall.  Devonian.  Taeniodictya  Ulrich. 
Devonian  and  Lower  Carboniferous.     Heliotrypa  Ulrich.     Lower  Carboniferous. 


Family 


Rhinidictyonidae  Ulrich. 


Zoaria  bifoliate,  continuous  or  jointed,  forming  compressed  hranches  or  leaf-like 
expansions;  occasionally  trifoliate.  Primitive  celU  sub-quadrate,  arranged  longitudinally. 
Both  primitive  and  superficial  apertures  elliptical  or  sub-circular,  sometimes  a  little 
truncated  posteriorly.  Inferior  hemiseptum  and  lunarium  ivanting.  Median  tubuli 
present  between  the  median  laminae,  and  between  the  longitudinal  rows  of  zooecial  tubes. 
Mesopores  absent,  but  vesicular  tissue  often  present.     Chiefly  Ordovician. 

Rhinidictya  Ulr.  {Stictopora  Ulr.,  non  Hall)  (Fig.  505,  et,  c).     Zoaria  composed  of 


Fig.  505. 

a-c,  Rhinidictya  mutaUlis  Ulr.  i/i  »nfi  surface  9/i.     c,  Several  zooecia  »5/j.    d,  c,  Cystalictya  gübcrti  Meek. 

Surface  l8/i  and  tangential  section  i8/j  (after  Ulrich). 

narrow,  compressed,  dichotomously  dividing,  straight-edged  branches,  attached  to 
foreign  bodies  by  a  continuous  expanded  base.     Ordovician  and  Silurian. 

Eurydictya,  Dicranopora,  Goniotrypa  Ulr.      Ordovician  and  Silurian. 

Euspilopora  Ulr.  Small,  irregularly  divided  branches,  with  serrated  or  wavy 
edges.     Devonian. 


346 


MOLLUSCOIDEA— BRYOZÖA 


PHYLUM  V 


Phyllodictya    Ulr.       Zoa3cial    tubes    long,    with    complete    diaphragms,    biit   no 
hemisepta.     Ordovician. 
W^ß^Jl^'^J.  PcLchydidya  (Fig.  506),  Trigonodictya  Ulr.     Ordovician  and 


Siliirian. 


Family  9.     Oystodictyonidae  Ulrich. 


Fig.  506. 
Pachydictya  foliata 


Zoaria  consisting  of  two  or  three  layers  of  cells  grown  together 
hack  to  hack,  forming  hranching,  perforated  or  entire  leaf-like  ex- 
pansions,  or  triangulär  hranches.  Primitive  cells  semi-cordate  or 
ohovate-acuminate  in  outline,  arranged  longitudinally.  Primitive 
aperture  suh-circular,  hut  hecoming  draivn  out  into  a  tuhular 
vestihule  as  growth  proceeds.  Superficial  aperture  ivith  peristome, 
and  more   or   less  ivell-developed    lunarium.      Interzooecial  Spaces 

^esota  ^'^^  n^entiai^ec'   ^^^^P'^*^^  ^V  vesicular  tissue,  often  filled  with  a  calcareous  deposit 

tion,  i4/i  (after  Ulrich),     near  the  surface.     Silurian  to  Permian. 

Cystodictya  Ulr.  {Arcanopora  Vine ;  Stictocella  Simpson)  (Fig.  505,  d,  e).  Zoaria 
ramose,  branches  sharply  elliptical,  with  siib-parallel,  non-poriferoiis  margins.  Inter- 
apertural  space  finely  striated,  granulöse  or  smooth ;  pits  and  cells  showing  only  in 
a  worn  condition.     Silurian  to  Permian. 

Coscinium  Keyserling  (Goscinotrypa  Hall) ;  Dichotrypa  Ulr.     Silurian  to  Permian. 

Taeniopora  Nich.  {Pteropora  Hall ;  Stictoporidra  Simpson).  Distinguished  from 
Cystodictya  by  having  a  longitudinal  ridge  or  keel,  which  divides  each  face  into  two 
equal  parts.     Devonian. 

Thamnotrypa,  Semiopora,  Äcrogenia,  Geramella,  Phractopora,  Prismopora,  Scalaripora 
Hall ;  Goniocladia  Etheridge  ;  Ptilocella  Simpson.    Devonian  and  Lower  Carboniferous. 

Evactinopora  Meek  and  Worth.  (Fig.  507,  &,  c).  Zoaria  free,  consisting  of  four  or 
more  vertical  leaves  arranged  in  a  stellate  or  cruciform  fashion.     Lower  Carboniferous. 


Fig.  507. 

a,  Glyptopora  sagenella-lata  Ulr.  i/^.     b,  Evactinopora  quinque  radiata  Ulr.  i/j.    c,  d,  E.  radiata 
Meek  and  Worthen  i/i  (after  Ulrich). 

Glyptopora  Ulr.  (Fig.  507,  a).  Zoaria  consisting  of  thin  expansions  traversed  on 
both  surfaces  by  salient  ridges,  or  of  uni-laminate  bases  on  which  the  coalescing  ridges 
of  the  Upper  surface  are  greatly  developed  and  form  large  leaves.     These  ridges  or 


ORDER  V  CHEILOSTOMATA  347 

leaves  are  coniposed  of  two  layers  of  cells  growing  in  opposite  directions  froin  a  niesial 
laniina.     Upper  surface  with  solid  maculae  or  "diinjdes."     Lower  Carboniferous. 

Family  10.     Rhinoporidae  Ulrich. 

Zocecia  simple,  oblong  or  rhomboidal,  prone  along  the  basal  membrane ;  vestibules 
direct,  hemisepta  ivanting ;  front  of  zocecia  below  vestibule  usually  strengthened  with  solid 
or  vesicular  tissue.     Silurian. 

Rhinopora  Hall.  Zoarium  of  imdulating,  bifoliate  expansions  ;  surface  smooth 
and  traversed  by  slender  bifurcating  ridges.     Silurian. 

Lichenalia  Hall.     Like  Rhinopora  but  unilaminar.      Silurian. 
Diamesopora  Hall ;  Stictotrypa  Ulrich.     Silurian. 

Family  11.     Oycloporidae  (provisional). 

The  following  genera,  all  from  the  Lower  Carboniferous,  and  of  doubtfiil  affinities, 
are  placed  in  this  family  :  Cyclopora  Prout ;  Cycloporella  Ulr.  ;  Proutella  Ulr. ; 
Worthenopora  Ulr. 

Order  5.     CHEILOSTOMATA   Busk. 

(Bryozoaires  cellulines,  d'Orbigny). 

Zocecia  oval,  turbinate,  urceolate,  quadrate  or  hexagonal,  arranged  usually  side  by 
side.  Orißce  more  or  less  anterior,  of  smaller  diameter  than  the  zocecium,  closed  by  a 
movable  cover.  Ova  commonly  matured  in  external  marsupia.  Appendicular  organs 
frequently  present. 

The  earliest  Cheilostomata  appear  sparsely  in  the  Jura  of  Normandy,  but  their 
progenitors  are  undoubtedly  to  be  looked  for  in  the  Paleozoic  Cryptostomata.  They 
attain  an  astonishing  development  in  the  Upper  Cretaceous,  and  in  the  Tertiaries  and 
existing  seas  they  greatly  surpass  the  Cyclostomata  in  number  and  variety  of  species. 

Not  all  of  the  Cheilostomata  have  a  completely  calcified  zoarium,  some  being 
corneous  and  flexible  (Flustridae),  and  others  having  the  front  wall  of  the  zocecia 
more  or  less  membraneous  and  the  rest  calcareous  (Membraniporidae).  Consequently, 
in  fossil  examples  of  the  latter,  the  zocecia  are  entirely  open  on  the  upper  or  front 
side  (Fig.  477).  Avicularia  and  vibracula  are  very  commonly  present,  and  are 
indicated  in  fossils  by  the  "  special  pores "  in  which  they  were  lodged.  External 
ovicells  are  more  commonly  developed  than  in  the  Cyclostomata,  and  usually  occur  as 
rounded,  blister-like  cavities  in  front  of  the  zocecial  apertures.  Reproduction  by 
gemmation  takes  place  at  the  growing  edge  of  the  colony,  the  young  cells  arising 
from  the  anterior  end  or  from  either  side  of  the  parent  cell ;  and  repeated  gemmation 
almost  always  results  in  a  more  or  less  regulär  arrangement  in  series.  Direct 
communication  between  adjoining  zooecia  is  effected  by  means  of  small  perforated 
plates  (communication  plates,  Rosettenplatten),  set  in  corresponding  positions  in  the 
side  walls  of  each  zocecium. 

In  the  Classification  of  the  Cheilostomata,  the  presence  or  absence  of  the  compensa- 
tion  sac  is  of  great  importance.  This  is  a  thin-walled  sac  opening  outward  through 
a  pore,  the  ascopore,  and  provided  with  muscles  whose  contraction  distends  the  sac 
with  the  result  that  the  polypide  is  extended. 

Although  much  work  has  been  done  in  recent  years  upon  the  morphological  and 
systematic  study  of  the  Cheilostomata,  their  Classification,  particularly  the  genera  of 
the  fossil  forms,  is  still  in  an  unsettled  condition.  The  older  Systems  of  d'Orbigny 
and  Busk  were  highly  artificial,  undue  promincnce  having  lieen  given  to  zoarial 
modifications ;   but   through   the  labours  of  Smitt,  Hincks  and  Waters,  who  have 


348 


MOLLUSCOIDEA— BRYOZOA 


PHYLUM  V 


demoiistrated  tlie  inucli  greater  importance  of  zocccial  cliaracters,  a  decided  advance 
was  made,  Levinsen's  stiidies  lipon  tlie  recent  Clieilostoiiiata  liave  resiüted  in  a 
splendid,  detailed  Classification  which  nnfortunately  depends  upon  cliaracters  making 
it  difRcult  of  application  to  the  fossil  forms.  Only  brief  descriptions  of  tlie  more 
iinportant  genera,  or  those  liaving  niimerous  fossil  representatives,  can  be  introduced 
liere. 

Suborder  A.     ANASCA   Levinsen. 

Gompensation  sac  wanting ;  frontal  löall  membraneous  or  calcareoiis,  d&pressed  and 
surrounded  by  raised  margins ;  opercular  and  subopercular  areas  not  separated  by  a 
calcareous  bar. 

Family  1.     Aeteidae    Hincks. 

Zoarium  miilinear,  adnate ;  zooßcia  partially  erect^  with  membraneous  apertures. 
Aetea  Lam.     Tertiary  and  Recent ;  Europe. 


Family  2.     Eucrateidae    Hincks. 

Zoaria    branching,    erect  and  free,    or    recumbent.       Zooecia    uniserial    or  biserial, 
pyriform,    with    a    sub-terminal    and    usually    oblique    aperture.       Avicularian    and 

vibracular  appendages  ivanting.  Cre- 
taceous  to  Recent. 

Eucratea     Lamx.     (Fig.     508). 

Zoaria  entirely  deciimbent,  or  com- 

posed  of  a  creeping  adlierent  base 

and  erect  braiicliing  slioots.    Zooecia 

calcareous  or  siib-calcareoiis,  rising 

oiie   from    anotlier  so   as    to    form 

Single   series.     Brauches   springing 

froin  tlie  front  of  a  zooeciiim  Ijelow 

Fig.  508.  the  aperture.    Cretaceoiis  to  Recent. 

Eucratea  lahmta  (Novak).      Cenomanian  ;    Velim,   Bohemia.  Gemellaria    Savigliy  ;     Notamia 

A,  Zoarium,   i/^.     B,   Zooecia,   tliree  of  them  with  fractured    -^^^        •  m     x-  i   -d  + 

waiis,  highiy  magnified  (after  Novak).  Fleming,     lei'tiary  aiid  Recent. 


Family  3.     Scrupocellariidae    Biisk. 

Zoarium  erect,  usually  jointed,  dichotomously  branching,  phytoid.  Zooecia  in  two 
or  more  series,  closely  united  and  arranged  in  the  same  plane.  Sessile  avicularia  and 
vibracula  generally  present.      Tertiary  and  Recent. 

Menipea,  Caberea  Lamx.  ;  Scrupocellaria  Van  Beiied.      Eocene  and  Recent. 


Family  4.     Oellulariidae    Levinsen.     {Salicornariadae    Biisk). 

Zoarium  erect,  sub-cylindrical,  dichotomously  branching,  usually  jointed.  Zooicia 
rhomboidal  or  hexagonal,  each  corresponding  to  an  area,  and  disposed  in  series  about  an 
imaginary  axis.  Front  depressed,  usually  concave.  Orifice  crescentic  or  semicircular, 
situated  slightly  above  the  centre  of  the  cell.  Ocecia  inconspicuous,  opening  at  or  near 
the  summit  of  the  area  above  the  orifice.  Avicularia  usually  present.  Cretaceoiis  to 
Recent. 


Gellularia  Pallas  {Cellaria  Lam,;  Salicornaria  Cuv.)  (Fig.  509).     Zoarium  jointed. 


ORDER  V 


CHEILOSTOMATA 


349 


tlie    Segments    sul)-cylindrical     and    coinicctcd    l)y    (Icxilde,    lioiny    tiil)c<.       Z^dvia 
inimerscd,  siiii-omidcd    hy  a  laiscd   Ix.fder,  di.^po^c'd  in  (juincLinx. 

Aviciilaiia  iriegu- 
larly  distiilnited, 
sitiiated  above  a  cell, 
or  occiipying  tlie 
place  of  one. 


Fio.  509. 

Cellularia  rhombiferu 
(Goldfuss).  Oligocene ; 
Kanfiingen,  near  Cassel. 
Enlarged  (after  Reuss). 


Encnisting  zoarium  of  Memtranipora,  with 
non-calcifled  zocecial  walls.     Magnified. 


Fig.  511. 

Memhranipora  plebeia 
(G.  and  H.).  Cretaceous ; 
N.  J.  Several  cells  highly 
magnified  (after  Gabb  and 
Hörn). 


Family  5.     Membraniporidae    Busk. 

Zoarium  calcareous  or  membrano-calcareous,  encrusting  or  erect,  in  the  latter  case 
bifoUate,  or  suh-cylindrical.  Zocecia  placed  side  hy  side,  and  forming  an  irregulär 
continuous  exjpansion,  or  in  linear  series.  Margins  raised,  the  depressed  front  more  or 
less  memhranous. 

Memhranipora  Blainv.  (?  Marginaria  Roemer ;  (?)  Dermatopora  Hagw.)  (Figs. 
510-511).  Zoaria  encrusting,  calcareous  or  sub-calcareous.  Zooecia  arranged 
irregularly  or  in  rows,  without  a  calcareous  lamina  on  the  front,  or  only  partially 
covered  by  one,  leaving  a  variously  sliaped  aperture.     Jurassic  to  Recent. 

Tremopora  Ortmann.  Like  Memhranipora,  but  has  a  large  avicularium  and 
bifurcated  spine  on  tlie  border.     Tertiary  to  Recent. 

Hagenoiüinella  Canu.      Cretaceous. 

Family  6.     Selenariidae    Busk. 

Zoaria  circular  or  irregulär  in  outline^  the  celluliferous  side  convex,  the  lower  concave 
or  ßat,  prohahly  free   in    the  mature  condition.      Upper   surface   areolated,    the  zooecia 


Fig.  512. 


ll;i-w. 


l'l'l' 


CrctacH'ous 
I',  ciilargt'd. 


Ijünt'lutru;. 


350 


MOLLUSCOIDEA— BRYOZOA 


PHYLUM  V 


immersed,  their  horders  elevated.  Orifice  rounded  or  semi-elli'ptical^  situated  more  or  less 
in  advance  of  the  depressed  front.  Small  vihracular  cells  usually  present.  Cretaceoiis 
to  Becent. 

LunuUtes  Lamx.  (Fig.  512).  Zooecia  arranged  in  series  radiating  from  the 
centre  and  bifiircating  as  they  advance  toward  tlie  border.  Vibracular  cells  usually 
elongate,  lying  in  linear  series  between  the  rows  of  zooecia.  Very  abundant  in  the 
Upper  Cretaceoiis  and  Tertiary ;  also  Recent. 

Vibracular  cells  wanting.  Zoojcia  equal, 
hexagonal,  not  arranged  in  radiating  series. 
Cretaceous. 

Selenaria  Busk.     Cretaceous  to  Recent. 


Stichopora    Hagw.    emend.    Busk. 


Fig.  513. 
Memhraniporella 
ahbotti  (G,  and  H.). 
Cretaceous ;  N.J. 
Zooecia  highly  mag- 
nified  (after  Gabb 
and  Hörn). 


Fig.  514. 


Cribrilina  heermanni 
(G.  and  H.).  Post-Plio- 
cene ;  Santa  Barbara 
Co.,Cal.  Zooecia  highly 
magnifled  (after  Gabb 
and  Hern). 


Family  7.     Oribrilinidae    Hincks. 

Zoaria  encrusting  or  erect.  Zooecia  having 
the  front  wall  more  or  less  fissured,  or  traversed 
by  radiating  furrows.     Cretaceous  to  Recent. 


Memhraniporella  Smitt  (Fig.  513).  Zoaria 
encrusting  or  rising  into  free  foliaceous  ex- 
pansions,  sometimes  consisting  of  superim- 
posed  layers.  Zocecia  closed  in  front  by  a 
number  of  flattened  calcareous  ribs  more  or  less  Consolidated  centrally.  Cretaceous 
to  Recent. 

Grihrilina  Gray  (Fig.  514).  Zoaria  usually  encrusting.  Zooecia  having  the 
front  more  or  less  occupied  by  radiating  or  transverse  rows  of  punctures,  each  row  in 
a  furrow  ;  orifice  semicircular  or  sub-orbicular,      Cretaceous  to  Recent. 


Family  8.     Onyohocellidae   JuUien  (emend.). 

Zoaria  encrusting  or  erect,  ramose,  continuous,  the  hranches  more  or  less  compressed 
and  hilaminar ;  surface  areolated.  Zooecia  usually  hexagonal,  their  margins  raised, 
the  front  not  entirely  calci- 
fied.  Opesial  aperture  of 
moderate  size,  generally  semi- 
elliptical,  sometimes  spread- 
ing  helow,  in  other  cases  suh- 
circular.  Oral  opening 
small,  usually  crescentic  or 
semicircular.  Ooecia  in- 
conspicuous ;  intercalated 
vicarious  avicularia  gener- 
ally present;  special  pores 
wanting.  Jurassic  to  Re- 
cent ;  chiefly  Cretaceous. 


Fig.  515, 


Onychocella  angu- 
Zosa(Reuss).  Upper 
Eocene  ;  Northern 
Italy.  Surface,  20/^ 
(after  Waters). 


Fig.  516. 

Vincularia  virgo  Hagw.  Upper  Cretaceous  ; 
Rügen.  a,  Portion  of  zoarium,  i/^.  h,  Cross- 
section.    c,  Vertical  section,  enlarged. 


Onychocella  JuUien  {Es- 
chara,  Flustrellaria,  p.p., 
d'Orb. ;  Cellepora,  Mem- 
hranipora,  Vincularia,  etc. 
auct.)  (Figs.  515,  516).  Zoaria  encrusting  or  erect.  Oral  opening  semicircular  or 
crescentic.  Avicularian  openings  simple,  oval ;  the  area  in  which  they  are  situated 
drawn  out  above.     Jura  of  Normandy,  and  Cretaceous  to  Recent. 


ORDER  V 


CHEILOSTOMATA 


351 


Vibracella  Waters  (Flustrellaria^  p.p.,  d'Orb.).  Difters  from  Onychocella  in  liaving 
a  larger  apeiture,  wliich  is  often  somewhat  expanded  below,  and  liaving  vibracular 
cells  instead  of  avicularia.     Cretaceons  and  Tertiary. 

(?)  CumuUpora  Münst.  (Fig.  517).     Zoaria  irregularly  massive.     Zocecia  partly 


CumuUpora  angulata  Münst,     Oligocene  ;  Doberg,  near  Bünde.    A,  Zoarium,  natural  size.     B,  Upper 
surface,  enlarged.     C,  Vertical  section,  enlarged  (after  Reuss). 

recumbent,  partly  erect,  and  placed  one  above  tbe  other,  so  tliat  tliey  appear  to  form 
tabulated  tubes.     Tertiary. 

Floridina  Jullien.  Like  Onychocella  but  opesium  trifoliate.  Cretaceoiis  to 
Recent. 

SmitUpora  Jullien  ;  Euritina  Cann.     Cretaceous  to  Recent. 


Family  9.     Microporidae    Smitt. 

Zooßcia  liaving  the  front  wall    entirely  calcareous ;    usually   with  sharply  elevated 
margins,  fissures  or  perforations.     Cretaceous  to  Recent. 

Micropora  Gray  (Fig.  518).  Zoaria  encrusting.  Zooecia  witli 
prominent  raised  margins :  the  front  depressed,  witli  a  Perforation 
at  each  upper  angle  below  the  semicircular  or  rounded  orifice. 
Cretaceous  to  Recent. 

Steganoporella  Smitt ;  Setosella  Hincks ;  Rhagasostoma  Kos- 
chinski  ;  Gupularia  Lam. ;  Gargantua  Jullien.     Tertiary  to  Recent. 

Suborder  B.     ASOOPHORA     Levinsen. 


■  '-^^ 

Fig.  518. 
Micropora  disparilis 

Compensation  sac  present,  opening  most  often  on  the  proximal  side  ^jo^g'jfg  ;^anta^ari 

of   the  operculum,  more  rarely  further  bara  Co.,'cai.  Zocecia 

back  through  a  median  pore  (ascopore).  (af^J  ^  Gabb"'and 

A    calcified  transverse  har    hetween   the  Hörn). 
opercular  and  suh-opercular  areas. 

Family  10.     Microporellidae  Hincks. 

Zoaria  encrusting  or  erect^  foliated  or  dendroid. 
Zooecial  orifice  more  or  less  semicircular^  with  the  lower 
margin  entire ;  a  crescentic  or  circular  pore  on  the  front 
wall  usually  just  beneath  the  orifice.    Cretaceous  to  Recent. 

Microporella  Hincks  (Fig.  519).  Zoarium  encrusting 
or    erect,    bilaminar.      Margin    of   zooecia    not    elevated. 


Fig.  519. 
Microporella  rudis  (Reuss). 


Oli- 


SgJi.^''^'"°'"-   ^l^P^^^"^f""«'    Orifice  with  a  straight,  entire  lower  border,  frequently 


352 


MOLLUSCOIDEA— BRYOZOA 


PHYLÜM  V 


with    oral    spiiies,      Usually  one  seini-lunate   or    circular   pore    beneatli   tlie   orifice, 
occasionally  two  or  tliree.      Tertiary  and  Recent. 

Family  11.     Porinidae    d'Orbigny. 

Zoaria  encrusting,  or  erect  and  ramified.  Zooßcia  with  a  raised  tubulär  or  sub-tubular 
orifice,  and  frequently  with  a  special  pore  on  the  front  wall.     Cretaceous  to  Recent. 

Porina  d'Orb.  Zoaria  consisting  of  flattened  or  snb-cylindrical  branclies,  celluli- 
ferous  on  botli  sides,  or  encrusting.  Witli  age  tlie  sj)aces  between  the  raised  apertures 
becoine  filled  with  a  porous  calcareous  deposit.  Avicularia  and  oa3cia  occasionally 
distinguishable.     Cretaceous  to  Recent. 

Family  12.     Smittinidae    Levinsen. 

For  this  and  the  next  foUowing  family  only  provisional  diagnoses  can  be  given  at 
the  present  time,  and  for  that  reason  none  is  attempted  here. 

Smittina  Norman  (ßmittia  Hincks).  Zoaria  encrusting,  or  erect  and  foliaceous. 
Primary  orifice  of  zooecia  sub-orbicular,  the  lower  margin  with  an  internal  median 
denticle.  Secondary  orifice  canaliculate  below  ;  generally  a  small  avicularium  either 
within  or  just  beneath  the  sinus.     Cretaceous  to  Recent. 

Mucronella  Hincks  (Fig.  520).  Similar  to  Smittina,  but  with  simpler  orifice, 
and  the  lower  part  of  the  peristome  elevated  into  a  more  or 
less  prominent  mucro.      Cretaceous  to  Recent. 

Porella  Gray.     Zoaria  encrusting  or  erect.     Zocecia  with  a 


Fig.  520. 

Mticronella  coccinea 
Abildg.  Miocene ;  Eisen- 
stadt, Hungary.  Anuiii- 
ber  of  zooecia  enlarged 
(after  Renss).  The  aper- 
tures are  denticulated, 
and  each  zooecium  has  a 
pair  of  avicularia.  o, 
Ovicell. 


Fig.  521. 

Lepralia  pallasiana  Moll. 
Recent ;  England.  Zocecia 
highly  magnitied  (after 
Hincks). 


Fi(}.  522. 

Schizoporella  cornuta 
(G.  and  H.).  Post- 
Pliocene ;  Santa  Bar- 
bara Co.,  Cal.  Zooecia 
highly  magnified 

(after      Gabb       and 
Hörn). 


semicircular  primary  orifice;  the  secondary  (adult)  orifice  elongate,  inversely  sub- 
triangular,  or  horseshoe-shaped,  and  enclosing  an  avicularium  with  a  rounded  or 
sub-triangular  mandible.      Cretaceous  to  Recent. 


Family  13.     Lepraliidae    Smitt. 

This  family,  like  the  preceding  one,  can  be  only  provisionally  defined  at  present. 

Lepralia  Johnson  (Fig.  521).  Zoaria  encrusting  or  rising  into  simple  or  branching 
expansions,  composed  of  one  or  two  layers  of  cells.  Zooecia  usually  ovate,  the  orifice 
with  a  thin  peristome  and  entire  lower  margin.  Rare  in  Cretaceous,  more  abundant 
in  Tertiary  and  Recent. 

Hippoporina  Neviani.  Like  Lepralia  but  aperture  constricted  ])y  two  lateral 
teeth.     Tertiary. 

Schizoporella  Hincks  (Fig.   522).     Zoaria  variable  :  zooccial  oiifice  varying  from 


ORDER  V 


CHEILOSTOMATA 


353 


semicircular  to  sub-orlncular,  the  loAver  margin  witli  a  distiiict  siniis.     Cretaceoiis  to 
Recent. 

Family  14.     Meniscoporidae    Caiiu. 

This  family  is  characterised  by  the  occurrence  of  three  kinds  of  zooecia  :  (1) 
typical  zocecia,  (2)  genesies  or  zooscia  bearing  internal  oa3cia,  and  (3)  aviciilaria. 
Abundant  in  Tertiary. 

Meniscopora  Gregory.     Aperture  constricted  as  in  Hippoporina. 

Schizostoma  Canu.     Like  Schizoporella  biit  with  genesies. 

Poristoma,  Poricella,  Smittistoma  and  Galvetina  Canii  ;  Lohopora  Levinsen. 

Family  15.     Reteporidae    Smitt. 

Retepora  Imperato  {Phidolophora  Gabb  and  Hörn)  (Fig.  523).  Zoaria  consisting 
usually  of  inosculating  brancbes  whicb  spring  from  an  encrusting  base.  Zooecia 
disposed  on  one  face  of  tlie  brancbes  only,  in  most  cases  immersed.     Primary  orifice 


Retepora  celhdosa  Linn.     Cra^ 
Suffolk,  England. 


Fig.  524. 

Myriozoum  jninctatum  (Phill.).  Miocene  ;  Ortenburg,  Bavaria.  A, 
Zoarium,  i/i-  B,  Upper  surface,  enlarged.  In  the  forward  portion  the 
apertures  are  open  ;  in  the  rear,  covered  over  by  a  calcareous  deposit. 
C,  Gross  section  of  a  branch. 


rounded  or  semi-elliptical  with  entire  border.  Afterwards  the  peristome  becomes 
miicli  raised  and  multiform  ;  usually  there  is  a  fissure  below,  or  there  may  be  a 
prominent  rostrum  bearing  an  avicularium.     Tertiary  and  Recent. 

Family  16.     Myriozoidae    Smitt. 

Myriozoum  Donati  {Myriopora  Blainv. ;  Vaginopora  Reuss)  (Fig.  524).  Zoaria 
consisting  of  thick,  dichotomously  dividing  branches,  obtuse  at  their  growing  ex- 
tremities,  and  rising  from  an  attached  basal  expansion.  Zooecia  disposed  about  an 
imaginary  axis,  even  at  the  surface,  their  boundaries  scarcely  distinguishable.  Entire 
surface  and  also  the  inner  walls  minutely  porous.  Orifice  above  the  centre  of  the 
zooecium,  sub-orbicular,  notched  or  canaliculate  below.  As  a  rule,  the  openings  are 
closed  on  the  lower  parts  of  tlie  branches  by  a  calcareous  pellicle.  Tertiary  and 
Recent  ;  perhaps  also  Cretaceous. 


Family  17.     Celleporidae    Busk. 

Zocecia  urceolate,  more  or  less  erect,  and  irregularly  crowded  together  ;  often  forming 
several  or  many  superimposed  layers. 

Gellepora    Fabricius,    emend.   Busk    (Spongites    Oken ;    Celleporaria    Lnmx.)  (Fig. 
525).     Zoarium  multiform,  encrusting,  or  erect  and  ramose.     Zocucia  in    the  oldcr 
VOL.  I  2  A 


354 


MOLLUSCOIDEA— BRYOZOA 


PHYLUM  V 


portions :  iiiore  or  less  erect  and  very  irregiüaiiy  disposed.      Orifice  terminal,  entire 
or  sinuated,  witli  or  wifhoiit  internal  denticles  ;  in  connection  witli  it  are  usually  one 

or  more  rostra  bearing  avicularia.  Inter- 
calated  avicularia  generally  present  also.  The 
surface  of  weatliered  specimens  dotted  by 
the  unequal  apertnres  of  vesicle-like  cells. 
Tertiary  and  Recent. 


Subclass  2.     PHYLAOTOLAEMATA 
AUman. 

The  Bryozoa  referred  to  this  subclass 
are  soft  -  bodied,  and  therefore  cannot  be 
expected  to  be  found  fossil  except  under 
unusual  conditions  of  preservation.  The 
fresh- water  Cenomanian  beds  of  Bohemia 
have  yielded  an  organism  incrusting  a  Unio, 
resembling  the  Recent  genus  Plumatella. 
Although  the  structure  is  too  iniperfectly  preserved  for  certain  Identification,  this 
specinien  {Plumatellites  proliferus  Fric)  may  well  be  a  fossil  representative  of  the 
Phylactolaemata. 


Fig.  525. 

Cellepora  conglomerata  Goldfuss.  Oligocene 
Astrupp,  near  Osnabrück.  A,  Zoarium,  i/i 
B,  Upper  surface,  enlarged. 


Range  and  Distribution  of  the  Bryozoa. 

The  class  Bryozoa  begins  in  the  earliest  OidaYifiianj  and  is  represented  con- 
tinuously  up  to  the  present  time.  The  older  Paleozoic  forms  belong  chiefly  to  two 
Orders — the  Cyclostomata  and  Trepostomata. 

A  considerable  nuinber  of  Cyclostomatous  genera  are  present  in  the  Ordovician, 
niost  of  them  being  closely  related  with  Mesozoic  and  Recent  types  ;  but  throughout 
the  remainder  of  the  Paleozoic,  and  in  the  Trias  also,  the  order  is  very  sparingly 
represented  (except  for  the  Ceramoporidae  and  Fistuliporidae),  and  in  some  parts  quite 
absent.  In  the  Jura  and  Cretaceous,  however,  a  reniarkable  increase  took  place, 
hundreds  of  species  being  known  from  these  forniations.  During  the  Tertiary  their 
strength  was  again  materially  reduced,  and  the  living  Cyclostomata  barely  exceed 
100  species  in  number. 

The  Trepostomata  appear  suddenly  and  in  great  variety  in  the  Ordovician,  from 
which  over  400  species  are  known,  but  entered  almost  immediately  upon  a  period  of 
decline.  From  the  Trenton  and  Cincinnati  groups  alone  more  species  have  been 
described  than  from  all  of  the  later  Paleozoic  formations  put  together.  There  is  at 
present  no  evidence  to  show  that  the  group  survived  later  than  the  Paleozoic  era,  but 
it  is  not  unlikely  that  their  descendants  may  be  found  among  certain  Mesozoic 
families,  such  as  the  Ceidae,  which  are  provisionally  assigned  to  the  Cyclostomata. 

The  Cryptostomata  are  likewise  confined  to  rocks  of  Paleozoic  age,  but,  as  has 
been  remarked  above,  may  be  very  confidently  regarded  as  the  forerunners  of  the 
Cheilostomata,  True  members  of  tlie  latter  group  are  first  met  with  in  the  Jura,  but 
they  develop  rapidly,  and  from  the  Cretaceous  onward  remain  the  dominant  type. 

The  Triassic  and  Liassic  Bryozoans  belong  chiefly  to  the  Cerioporidae.  This 
family,  together  with  the  Diastoporidae,  Fascigeridae,  and  other  members  of  the 
Cyclostomata,  is  abundantly  represented  in  the  Middle  Jura  of  Lorraine,  Southern 
Germany,  England  and  Normandy.  The  Upper  Jura,  on  the  contrary,  yields  com- 
paratively  few  Bryozoan  fossils. 

The  Cyclostomata  still  predominate  in  the  Neocomian  and   Gault,  but  in  the 


CLASS  II  BEACHIOPODA  355 

Cenomanian  a  niimber  of  Clieilostomatous  genera  make  their  appearance.  The  fauna 
is  especially  well  developed  in  tlie  vicinity  of  Le  Mans,  Havre  and  Essen,  and  in 
Saxony,  Northern  Germany  and  Bohemia. 

Bryozoans  are  surprisingly  abundant  in  the  Upper  Cretaceous,  particularly  in  the 
Upper  Pläner  of  Northern  Germany,  Saxony  and  Bohemia,  in  the  White  Chalk,  and 
the  facies  of  Aix-la-Chapelle  and  Maestricht.  D'Orbigny  alone  has  described  not  less 
than  547  species  of  Upper  Cretaceous  Cyclostomata,  and  about  300  Cheilostomata  ; 
many  of  these,  however,  are  Synonyms  or  unrecognisable. 

The  Cheilostomata  retain  their  siipremacy  throughout  the  Tertiary  period.  The 
Eocene  and  Oligocene  deposits  of  the  northern  and  southern  slopes  of  the  Alps  are 
remarkable  for  the  abundance  of  their  Bryozoan  remains ;  some  of  the  most  noted 
Eocene  localities  being  Kressenberg,  Hammer  and  Neiibeuern  in  Upper  Bavaria  ; 
Mossano,  Crosara  and  Priabona,  near  Vicenza ;  and  Oberburg  in  Styria.  The 
Oligocene  of  Northern  Germany,  and  the  Miocene  of  Touraine,  the  Rhone  Valley, 
Upper  Swabia,  and  the  Vienna  Basin,  are  also  remarkably  rieh  in  Bryozoan  remains. 
The  Pliocene  fauna  of  Italy,  Rhodes,  Cyprus  and  England  (notably  the  Coralline 
Crag)  is  made  up  almost  entirely  of  existing  genera,  and  in  many  cases  of  existing 
species. 

[The  revision  of  the  preceding  chapter  on  Bryozoa  has  been  prepared  for  the  present 
edition  by  Dr.  R.  S.  Bassler,  of  the  United  States  National  Museum  at  Washington,  D.C. — 
Editor.  ] 

Olass  2.    BRAOHIOPODA  Dumeril.^ 

(Revised  by  Charles  Schuchert.) 

Bivalved  Molluscoidea  with  inequivalved,  equilateral  shells  attached  to  extraneous 
objects  by  a  posterior  Prolongation  of  the  body,  or  pedicle,  throughout  life  or  during 

^  Literature :  A.  Anatomy  and  Embryology. — Hancocky  A.,  On  the  Organisation  of  Brachio- 
poda.  Phil.  Trans.,  1858,  vol.  cxlviii. —  Morse,  E.  S.,  On  the  Early  Stages  of  Terebratulina 
septentrionalis.  Mem.  Boston  Soc.  Nat.  Hist.,  1873,  vol.  ii. — On  the  Systeniatic  Position  of  the 
Brachiopoda.  Proc.  Boston  Soc.  Nat.  Hist.,  1873,  vol.  xv. — KovalevsM,  A.  0.,  Observation  on  the 
Development  of  Brachiopoda.  Proc.  Inip.  Soc.  Amateur  Nat.  Moscow,  1874,  vol.  xiv. — Brooks, 
W.  K.,  The  Development  of  Lingula  and  the  Systematic  Position  of  the  Brachiopoda.  Sei.  Results 
Chesapeake  Zool.  Lab.  1878. — ShipLey,  A.  J£.,  On  the  Structure  and  Development  of  Argiope. 
Mittheil.  Zool.  Station  Neapel,  1883,  vol.  iv. — Oehlert  in  Fischers  Manuel  de  Conchyliologie. 
Paris,  1887. — Beecher,  C.  E.,  and  Clarke,  J.  M.,  The  Development  of  some  Silurian  Brachiopoda. 
Mem.  New  York  State  Museum,  1889,  vol.  i. — Beecher,  0.  E.,  Development  of  the  Brachiopoda. 
Amer.  Journ.  Sei.,  1891-92,  vols.  xli.,  xliv. — Revision  of  the  Families  of  Loop-bearing  Brachiopoda. 
Trans.  Conn.  Acad.,  1893,  vol.  ix. — Beecher,  C.  E.,  and  Schuchert,  C,  Development  of  the  Shell 
and  the  Brachial  Supports  in  Dielasma  and  Zygospira.  Proc.  Biol.  Soc.  Washington,  1893, 
vol.  viii. — Biickman,  S.  S.,  Homoeomorphy  among  Jurassic  Brachiopoda.  Proc.  Cotteswold  Nat. 
Field  Club,  1901,  vol.  xiii. — Brachiopod  Homoeomorphy :  Pygope,  Antinomia,  Pygites.  Quart.  Journ. 
Geol.  Soc.  London,  1906,  vol.  Ixii. — Brachiopod  Homoeomorphy  :  "  Spirifer  glaber."  Ibid.,  1908, 
vol.  Ixiv. — Blochmann,  F.,  Untersuchungen  über  den  Bau  der  Brachiopoden.     Jena,  1892,  1900. 

B.  Distribution  of  Recent  Forms. — Schuchert,  C,  Paleogeographic  and  Geologie  Signiticance  of 
Recent  Brachiopoda.     Bull.  Geol.  Soc.  America,  1911,  vol.  xxii. 

C.  Bibliography. — Dali,  W.  H.,  Index  to  the  Names  which  have  been  applied  to  the  Sub- 
divisions  of  the  Class  Brachiopoda.  Bull.  U.S.  Nat.  Museum,  No.  8,  1877.— Davidson,  T.,  and 
Dalton,  W.  H.,  Bibliography  of  the  Brachiopoda.  Palaeont.  Soc,  1S86.— Schuchert,  C,  Synopsis 
of  American  Fossil  Brachiopoda.     Bull.  U.S.  Geol.  Surv.,  1896,  No.  87. 

D.  Systematic  Workü.  —  Walcott,  C.  D.,  Cambrian  Brachiopoda.  Mon.  51,  U.S.  Geol.  Surv., 
1912. — Davidsoll,  T.,  Monograph  of  British  Fossil  Brachiopoda.  Palaeontographical  Society, 
1851-86,  vols.  i.-v. — Idem,  A  Monograph  of  Recent  Brachiopoda.  Trans.  Linn.  Soc,  1886-88, 
vol.  iy.  — Waagen,  W.,  Salt  Range  Fossils.  Palaeont.  Indica,  ser.  13,  1882-85,  vol.  i.—Bittner,  A., 
Brachiopoda  der  Alpinen  Trias.  Abhandl.  k.k.  geol.  Reichs-Anst.,  Wien,  1891-92,  vols.  xvi.,  xvii.— 
Hall,  J.,  and  Glarke,  J.  M.,  Introduction  to  the  Study  of  Palaeozoic  Brachiopoda.  Palaeont.  New 
York,  1892-95,  vol.  viii.,  parts  1,  2.— Au  Introduction  to  the  Study  of  the  Brachiopoda.  Rept. 
New   York  State  Geologist,   1892-93,  parts   1,   2.— Schuchert,    C,   Synopsis,    etc..   see  above.— 


356  MOLLUSCOIDEA  phylum  v 

only  a  portion  of  their  existence,  or  cemented  ventrally.      Valves  ventral  and  dorsal. 

In  composition,  phosphatic  or  calcareous  or  hoth.     Animal  enveloped  ly  two  pallial 

memhranes  intimately  related  to  the  shell.      Within  the  mantle  cavity  at  the  sides  of  the 

mouth  are  inserted  the  two,  more  or  less  long,  oral,  usually  sinrally  enrolled,  cirrated 

hrachia,  which  are  variously  modified,  and  are  supported  in  the  Terehratulacea  and 

Spiriferacea  by  an  internal  calcareous  skeleton,  or  hrachidium,  attached  to  the  dorsal 

valve.     Anus  present  or  absent.     Central  nervous  System  consisting  of  an  oesophageal 

\  ring  with  weakly  developed  hrain  and  infra-oesophageal  ganglionic  swellings.     Blood- 

S    vascular  System  probaUy  present  with  the  sinuses  developed  into  vascular  dilatations 

\    at  the  hack  of  the  stomach  and  elsewhere.     Sexes  separate.     Exclusively  marine. 

The  class  begins  well  represented  in  the  Lower  Cambrian,  attains  its 
maximum  development  in  the  Silurian  and  Devonian,  and  is  represented  by 
about  158  living  species.  Probably  upwards  of  7000  fossil  and  recent  species 
have  been  described  ;  these  are  distributed  in  450  genera,  grouped  in  42 
families,  14  superfamilies,  and  4  Orders. 

Cuvier  (1792  and  1802)  was  the  first  to  distinguish  the  Brachiopods  from 
the  Acephala,  and  created  for  them  a  fourth  family  in  his  class  of  Molluscs. 
To  Dum^ril  (1806)  we  owe  the  now  generally  accepted  class  name  Brachio- 
poda,  or  arm-footed  animals.  Since  the  arms,  or  brachia,  are  not  homologous 
with  the  foot  of  Molluscs,  Gray  (1821)  changed  the  name  to  Spirobranchiopoda ; 
BlsLinYiWe  (1824:)  to  Falliobranchiata  ;  Risso  (1826)  to  Branchiopoda ;  Broderip 
(1839)  to  Brachiopodidae ',  Agassiz  (1847)  to  Branchionopoda ;  Bronn  (1862)  to 
Brachionocephala ;  Paetel  (1875)  to  Branchionobranchia ;  and  Haeckel  to  Spiro- 
hranchia.  None  of  these  has  displaced  Dumöril's  term,  though  the  latter  is 
founded  on  a  false  physiological  Interpretation  of  the  brachia. 

Bxternal  Characters  :  Form. — The  shells  of  Brachiopods  are  very 
variable  in  form.  Usually  both  valves  are  convex,  but  they  may  be  nearly 
flat,  with  the  interior  cavity  extremely  shallow,  or  the  dorsal  valve  may  be 
concave  and  follow  closely  the  curvature  of  the  convex  ventral  valve.  The 
ventral  valve  may  be  cone-shaped,  with  the  dorsal  operculiform,  or  the 
former  may  be  so  modified  by  cementation  as  to  assume  the  appearance  of  a 
Cyathophylloid  coral.  The  shell  is  commonly  rostrate,  with  the  ventral  beak, 
or  apex,  more  or  less  incurved  over  that  of  the  dorsal  valve,  or  the  valves 
may  be  very  greatly  extended  transversely.  In  fact,  the  form  of  the  shell  of 
Brachiopods  is  so  variable  that,  as  a  rule,  no  greater  value  than  specific  can 
be  attached  to  this  feature. 

Fixation. — The  animal  is  generally  attached  to  extraneous  objects  by  a 
muscular  pedicle  which  projects  either  from  between  the  contracted  posterior 
margin  of  the  two  valves  (Fig.  536,  A),  through  an  opening  in  or  under  the 
beak  (Fig.  535,  B),  or  through  the  ventral  valve  (Fig.  556,  A).  With 
increasing  age,  however,  the  pedicle  opening  frequently  becomes  closed,  and 
the  pedicle  itself  atrophied.     The  animal  may  then  be  anchored  by  spines 

Schellwien,  E.,  Die  Fauna  der  Trogkofelschicliten.  Abhandl.  d.  k.k.  geol.  Reichs- Aiist.,  1900, 
vol.  xvi.,  pt.  1. — Skupin,  H.,  Die  Spiriferen  Deutschlands.  Geol. -pal.  Abhandl.,  1901,  vol.  viii.— 
Tscher nyschew,  T. ,  Die  obercarbonischen  Brachiopoden  d.  Ural  und  d.  Timan.  Mein.  Comite  Geol. , 
1902,  vol.  xvi.,  No.  2. — Girty,  G.  H.,  The  Guadalupian  Fauna.  Profess.  Paper  58,  U.S.  Geol.  Surv., 
1908. — Buckman,  S.  S.,  Brachiopod  Nomenclature.  Ann.  Mag.  Nat.  Hist.  (7),  1906,  vol.  xviii. 
— The  Genotype  of  Terebratula.  Ibid.,  1907,  vol.  xix. — Brachiopod  Morphology  :  Cincta,  Eudesia, 
and  the  Development  of  Ribs.  Quart.  Journ.  Geol.  Soc.  London,  1907,  vol.  Ixiii. —  Weiler,  S., 
Internal  Characters  of  some  Mississippian  Rhynchonelliform  Shells,  Bull.  Geol.  Soc.  America, 
1910,  vol.  xxi. — Genera  of  Mississippian  Loop-Bearing  Brachiopoda.     Journ.  Geol.,  1911,  vol.  xix. 


CLASS  II  BRACHIOPODA  357 

(Chonetes,  Produäus)  or  be  cemented  by  the  whole  or  a  part  of  the  surface  of 
the  ventral  valve  (Crania,  Davidsonia,  Thecidea,  Streptorhynchus).  In  some  cases 
(Glottidia  and  Lingula)  Brachiopods  live  throughout  life  partially  buried  in  the 
sand  or  mud  of  the  sea-bottom. 

Ornamentation. — The  external  form  and  ornamentation  of  the  shell  afford 
important  characters  for  determining  the  species.  The  anterior  margin  of 
one  valve  is  frequently  indented  by  a  median  sinus,  and  the  other  usually 
exhibits  a  corresponding /oZc?,  or  elevation. 

In  the  earliest  shell  growth  stages  Brachiopod  shells  are  invariably  smooth, 
and  may  remain  so  throughout  life,  but  the  greater  number  develop  radial 
Striae,  ribs  or  undulations,  and  these  are  usually  crossed  by  concentric  growth 
lines,  or  lamellae,  which  are  sometimes  of  great  width,  or  may  be  extended  into 
spines.  There  may  be  more  or  less  long  tubulär  spines  scattered  over  one  or 
both  valves,  or  sometimes  restricted  to  a  single  row  along  the  cardinal  line. 
Under  the  term  Loricatae,  Leopold  von  Buch  included  all  Brachiopods  in  which 
the  radial  folds,  or  costae,  are  arranged  in  regulär  succession  in  such  manner 
that  elevated  ridges  at  the  anterior  margin  of  one  valve  coincide  with  the 
indentations  of  the  other.  In  the  Biplicatae,  a  median  fold  or  sinus  is 
bordered  on  either  side  by  a  broad  fold.  In  the  Cindae,  the  plications  of  the 
two  valves  meet  at  the  anterior  margin  in  such  manner  as  to  form  a  straight 
instead  of  a  crenulated  line,  as  in  the  Biplicatae.  In  young  specimens  the 
ribs  and  folds  are  less  prominent  and  numerous  than  at  maturity.  In  very  old 
or  senile  individuals  the  shell  is  usually  thickened  and  obese,  and  the  growth 
lines  are  much  crowded  anteriorly.  At  this  stage  inherited  specific  characters 
are  seen  to  disappear,  and  at  the  same  time  new  ones  may  be  introduced. 

Shell  Strudure. — The  test  of  Brachiopods  is  composed  of  laminae  of  various 
structure  and  composition,  but  difFers  considerably  from  that  of  Molluscs. 
The  shell  may  be  wholly  calcareous  or  alternately  calcareous  and  corneous. 
When  entirely  calcareous  the  laminae  are  never  more 
than  three  in  number :  an  inner  thick  prismatic  layer, 
an  intermediate  laminar  layer,  and  an  outer  epidermal 
film.  The  inner  layer  is  made  up  of  flattened  prisms  of 
calcite  arranged  parallel  to  one  another  with  great  regu- 
larity,  and  forming  an  acute  angle  with  the  surface  of  the 
shell  (Fig.  526).  In  the  Thecidiidae  these  fibrous  prisms 
are  so  intimately  united  with  one  another  that  the  shell 
substance  appears  almost  homogeneous.  Very  often  the 
fibrous  layer  is  perforated  by  a  series  of  minute  canals 
which  pass  from  one  surface  of  the  valve  to  the  other 
in  a  more  or   less  vertical  direction,  and  are  somewhat  p^^  ^26 

dilated  externally.    These  canals  contain  tubuli,  or  certain      prismatic  fibrous  struc- 
prolongations  derived  from   the  mantle,  but  never  com-  (S[Aj?SÄto^^ 
municate  with  the  exterior,  owing  to  the  fact  that  the  (after  Carpenter). 
laminar  layer   of    the    shell   is    always    covered    with    a 
chitinous  epidermis  (periostracum).     With  the  aid  of  a  magnifier  the  openings 
of  these  canals  are  visible  in  fossil  forms,  and  they  may  be  also  seen  in  recent 
specimens  after  the  epidermis  has  been  removed  by  an  application  of  caustic 
potash  (Fig.  527).     According  to  the  presence  or  absence  of  tubuli,  Brachiopods 
are  distinguished  as  pundate  or  impundate. 

The  Craniidae  have  thick  shells  composed  of  concentric  layers  of  carbonate 


358 


MOLLUSCOIDEA 


PHYLÜM  V 


of  lime.     In  Crania  the  shell  substance  is  homogeneous,  and  punctured  by 
distally  branching  canals.     In  the  Lingulidae  and  Obolidae  the  shell  consists 

of  alternating  layers  of  phosphate  of 

lime,   admixed   with   lime   carbonate, 

and  a  lustrous  horny  substance  known 

as  ceratin.     The  calcareous  layers  are 

prismatic,  and  are  traversed  by  fine 

tubuli  (Fig.  528).     It 

is    believed    that   the 

function  of  the  punc- 

tae  is  for  respiration, 

but  the  fact  that  these 

extensions    of    the 

mantle    are    not    ex- 

verticai     section  posed    to    the    water 

of   a  Lingula  shell 


Fig.  527. 


A,  Punctate  exterior  of  a  Terebratuloid  shell, 
slightly  enlarged.  B,  Vertical  section  of  shell  of 
Magellania  flavescens,  showing  distally  enlarged  tubules, 
Joo/j.  c,  Inner  surface  of  Magellania  shell,  showing 
ends  of  tubules  and  oblique  calcareous  prisms,  loo/^ 
(after  Carpenter). 


sLrvinT    anernate    Hiay    not    aCCOrd    with 

corneous    («)    and  this  explanation. 

calcareous  (ö)  layers.  tt-  f  -r. 

Strongly    magnified  VolveS. BrachlO- 

(after  Gratiolet).  t  i    t      i    i 

pods  are  delicately 
constituted  animals,  covered  by  two  very  vascular  mantle  lobes  which  secrete 
the  calcareous  or  corneo- calcareous  valves,  of  which  one  is  dorsal  and  the 
other  ventral  in  position.  The  valves  are  often  thin  and  of  unequal  size,  but 
the  inequality  is  rarely  of  such  a  nature  as  to  disturb  the  bilateral  symmetry 
of  the  shell. 

During  life  the  ventral  valve,  which  is  commonly  the  larger  of  the  two,  occu- 
pies  typically  a  superior  position,  and  the  dorsal  is  down.  But  in  describing 
the  shell,  it  is  always  so  oriented  that  the  posterior  margin,  or  hinge-line,  is 
placed  above,  and  the  anterior  one  below.  A  line  drawn  from  the  beak  to  the 
anterior  margin  describes  the  length ;  and  one  at  right  angles  to  the  same,  in 
the  direction  of  right  and  left,  the  width ;  a  third  line  drawn  perpendicularly 
to  the  other  two,  and  passing  through  the  centres  of  the  valves,  measures  the 
thicJcness.  In  the  Protremata  and  Telotremata  the  ventral  valve  is  convex,  and 
curved  in  such  manner  at  the  posterior  margin  as  to  form  a  heak  The  beak 
may  be  pointed,  or  it  may  be  perforated  by  a  round  opening,  or  foramen,  for 
the  Protrusion  of  the  pedicle.  In  many  cases,  however,  the  pedicle  opening 
lies  underneath  the  apex  of  the  beak,  and  sometimes  encroaches  upon  a 
portion  of  the  dorsal  valve.  In  the  Atremata  the  pedicle  emerges  from 
between  the  two  valves ;  in  the  Neotremata  the  posterior  margin  of  the 
ventral  valve  is  notched,  or  there  may  be  a  small,  circular,  eccentric  Per- 
foration, or  a  more  or  less  long,  narrow  slit.  In  the  Telotremata  the  pedicle 
opening,  or  delthyrium,  which  is  originally  triangulär  in  form,  becomes  either 
wholly  or  partially  closed  by  the  growth  of  deltidial  plates.  In  the  Protremata 
the  delthyrium  is  closed  by  a  true  deltidium,  while  in  the  Neotremata  and 
Atremata  a  similar  looking  plate  may  be  present,  but  as  it  is  of  a  difFerent 
origin,  being  secreted  by  the  mantle,  it  is  called  the  homceodeltidium. 

The  Cardinal  area  is  a  term  applied  to  the  flattened  or  curved  triangulär  area 
which  is  frequently  observable  between  the  hinge-line  and  the  beak  (Fig.  529).  It 
is  more  highly  developed  in  the  ventral  than  in  the  dorsal  valve,  and  is  bisected 
medially  by  the  triangulär  delthyrium.  A  true  cardinal  area  is  absent  in  the 
Atremata  and  Neotremata  ;  but  when  a  small  area  is  present  in  these  Orders,  it  is 


CLASS  II 


BRACHIOPODA 


359 


Fio,  529. 
Cyrtina  heteroclyta 


called  a  false  cardinal  area  (Fig.  546,  B,  G).     A  split  tubulär  structure,  or  syrinxy 

whicli  partially  encloses  tlie  pedicle,  is  developed  in  the  delthyrium  of  some  spire- 

beariiig  forms. 

The  deltidium  has   its  origiu    in  the   Cephalula  stage  of  Protremata  {Thecidea 

mediterranea)  contemporaneously  with  the  rudiments  of  the  dorsal 

and  ventral  valves,  while  the  embryo  is  still  in  the  free  swimming 

condition.     The  dorsal  valve  and  incipient  deltidium  appear  first, 

being  secreted  by  the  rudimentary  dorsal  mantle  and  the  dorsal  sur- 

face  of  the  body,  the  latter  subsequently  becoming  the  pedicle.      The 

ventral  valve  is  formed  last,  but  is  widely  separated  from  the  dorsal. 

Between  the  two  valves  is  placed  the  short  and  thick,  but  as  yet 

unattached  pedicle,  on  the  dorsal  surface  of  which  the  third  plate, 

known  as  the  prodeltidium,  still  remains.     Shortly  before  the  animal 

becomes  fixed  by  the  pedicle,  the  prodeltidium  fuses  with  the  posterior   (Defr.).    High  car- 
-.1  iimi  TT.  ,.  ^  ,       dinal  arpa  of  ventral 

margin  ot  the  ventral  valve.  The  pedicle  is  at  this  stage  entirely  valve  showing  dei- 
surrounded  by  shell,  being  enclosed  on  one  side  by  the  ventral  valve,  fuged'"  deiTidia^ 
and  on  the  other  by  the  deltidium.  The  latter  plate  then  continues  piates,  or  i)seudo- 
to  grow  as  one  piece,  extending  from  the  apex  in  an  anterior  direction, 
and  is  secreted  entirely  by  the  pedicle  (Fig.  541).  The  deltidium  is  never  punctate 
in  structure,  but  it  may  l)ear  spines  (Äulosteges),  and  sometimes  exhibits  a  round  er 
pedicle  Perforation  {Glitambonites).  The  deltidium  is  characteristic  of  the  Protremata, 
while  a  similar  plate,  the  homoeodeltidnim,  is  developed  in  some  of  the  Neotremata 
and  Atremata.  This  covering  of  the  delthyrium  is  always  present  in  the  young  of  the 
Protremata,  but  is  absent  in  the  Telotremata.  In  many  of  the  Protremata  (Orthidae, 
etc.)  the  deltidium  is  only  present  in  nepionic  stages  of  the  individual,  being 
resorbed  at  maturity ;  but  in  the  great  majority  of  these  forms  it  remains  persistent 
throughout  life. 

Deltidial  -piates  occur  only  in  the  order  Telotremata,  and  consist  of  two  pieces 
which  begin  as  narrow,  linear,  calcareous  piates,  growing  medially  from  the  walls  of 
the  delthyrium,  They  gradually  increase  in  size,  and  usually  come  in  contact 
medially  with  one  another,  either  below  or  above  the  pedicle  foramen,  and  are 
secreted  by  an  extension  of  the  ventral  mantle  lobe.  Thus  in  respect  to  their  origin 
they  differ  from  the  deltidium  of  the  Protremata,  which  is  secreted  by  the  pedicle, 
and  not  by  the  mantle.  The  deltidial  piates  are  never  present  in  the  earliest  growth 
stages  of  the  shell,  the  delthyrium  being  then  an  open  triangulär  fissure  through 
which  the  pedicle  is  protruded.  In  the  adult  stage  the  deltidial  piates  may  remain 
as  narrow,  linear  discrete  piates  (Fig.  530,  B) ;  may  meet  beneath  the  pedicle  foramen 


Fig.  530. 

A,  Cyclothyris  vespertilio  (Brocchi),  with  united  deltidial  piates.  B,  Terebratella  dorsata  (Lam.),  with 
discrete  deltidial  piates.  C,  Young  specimen  of  Stringoce2yhalus  bnrtoni  (Defr.),  with  the  deltidial  piates  united 
above  the  foramen. 


(Fig.  535,  B) ;  or  they  may  wholly  enclose  the  pedicle  (Fig.  530,  A).  The  deltidial 
piates  frequently  unite  l)y  fusion,  when  they  closely  resemble  a  true  deltidium,  and 
are  known  as  a  pseudodeltidium  {Gyrtia,  Cyrtina,  Fig.  529). 

The  chüidium  is  a  convex  plate  which  often  covers  the  cardinal  process  of  the 


360 


MOLLUSCOIDEA 


PHYLUM  V 


dorsal  valve  in  the  Protremata.  It  is  particularly  well  developed  in  the  families 
Clitambonitidae  and  Stropliomenidae  (Fig.  585,  B).  The  chilidium  is  not  to  be  homo- 
logised  with  the  deltidium,  since  it  never  appears  earlier  than  the  adolescent  stage, 
and  is  apj)arently  a  secretion  of  the  dorsal  mantle  lobe.  Both  its  origin  and  phyletic 
significance  are  therefore  very  difterent  from  those  of  the  deltidium. 

The  listrium  is  a  plate  closing  the  progressive  track  of  the  pedicle  opening  or 
pedicle  cleft,  in  some  Neotremata,  posterior  to  the  apex  of  the  ventral  valve. 

Internal  Characters  of  the  Shell :  Articulation. — The  two  valves  are 
held  in  apposition  either  by  muscles  only  (Atremata  and  Neotremata),  or  they 
are  united  by  articulation  (Protremata  and  Telotremata).  In  the  latter  case 
there  are  to  be  seen  in  the  ventral  valve  a  pair  of  cuneate  or  tooth-shaped 
projections,  one  on  either  side  of  the  delthyrium,  called  the  hinge-teeth  (Fig. 
535,  B),  which  fit  into  the  so-called  dental  sockets  of  the  dorsal  valve.  Articu- 
lation is  also  aided  by  the  cardinal  process,  which  is  a  more  or  less  well- 
developed  apophysis  of  the  dorsal  valve,  and  is  received  between  the  teeth  of 
the  ventral  valve.  By  the  contraction  of  the  muscles  attached  to  the 
cardinal  process,  the  valves  are  opened  along  the  anterior  and  lateral 
margins;  but  when  shut,  the  test  entirely  encloses  the  soft  parts  of  the 
animal. 

The  dental  sockets  are  bounded  on  the  inside  by  hinge-plates  (Fig.  535,  A), 
which  are  often  supported  by  vertical  or  inclined  septal  plates  extending  to 


Fig.  531. 

,«,V^'^1n  willTfpnHlÄI'lf  ^-  •^'  ^^''^^^rH '  fl^^^y  ^™«  supported  by  two  simply  curved  crura.  B,  Theco- 
Th  f  nnl  nf  L?ni-i^^^^^'r  P/.""'!'  ^'^  .T""^^'^-  ^'  ^^^^ieospim ;  and  D,  Cyrtina  ;  outwardly  coiled  spiralia. 
E.H,  Loops  of  Brachiopods.    E,  Centronella ;  F,  Dielasma ;  G,  Terebratella  ;  H,  Megathyris. 

the  bottom  of  the  shell.  The  teeth  of  the  ventral  valve  are  sometimes 
supported  by  lamellae  known  as  the  dental  plates.  In  addition  to  the  dental 
plates,  which  frequently  attain  considerable  size,  there  may  be  a  median 
septum  of  variable  proportions.  This  may  begin  beneath  the  beak  of  the 
valve,  and  may  sometimes  extend  as  far  as  the  anterior  margin  (Fig.  535,  A). 
Some  forms  are  also  provided  with  lateral  septa  (Thecidiidae). 


CLASs  II  BRACHIOPODA  361 

Brachial  supports. — Of  special  systematic  importance  are  the  brachidia,  or 
internal  skeleton  of  the  fleshy  arms  (Fig.  531),  which  occur  in  the  Spiriferacea 
and  Terebratulacea.  The  brachidia  are,  as  a  rule,  prolonged  basally  from  the 
crura,  and  are  extremely  variable  in  form.  They  usually  pass  through  a 
more  or  less  complex  series  of  metamorphoses  during  the  growth  of  the 
individual,  and  do  not  attain  their  complete  development  until  the  animal  has 
reached  maturity. 

The  simplest  form  of  brachial  supports  is  found  in  the  Rhynchonellacea  and 
Pentameracea,  where  it  consists  of  two  short,  or  only  moderately  long,  curved 
processes  called  the  crura  when  discrete,  and  cruralium  when  the  plates  are 
united.  The  crura  are  attached  to  the  hinge-plates.  The  cruralium  is 
formed  by  the  union  ;of  the  crural  plates  in  the  Pentameracea.  It  serves 
for  the  attachment  of  muscles,  and  may  either  rest  upon  the  bottom  of  the 
valve,  or  may  be  supported  by  a  median  septum.  When  the  crura  remain 
separate,  and  are  therefore  not  for  muscular  insertion,  they  are  homologous 
with  and  the  equivalent  of  the  crura  in  the  Rhynchonellidae. 

In  the  Spiriferacea,  two  thin,  spirally  coiled  ribbons,  or  spiralia,  are 
given  off  from  the  crura ;  the  coils  exhibiting  great  diversity  in  form,  in  the 
number  of  volutions,  and  in  the  direction  of  the  hollow  cones  (Fig.  531, 
B,  C,  D).  The  spiralia  are  usually  joined  by  a  transverse  band  or  jugum 
(Fig.  531,  D).  When  the  latter  is  discontinuous,  the  parts  are  called  the 
jugal  processes.  The  bifurcations  of  the  jugum  may  enter  between  the  con- 
volutions  of  the  spiralia,  and  may  be  continuous  with  them  to  their  outer 
ends,  forming  what  is  termed  a  double  spiral  or  diplospire  (Fig.  531,  5).  In 
the  Terebratulidae,  the  brachia  are  also  extensions  of  the  crura,  and  form  free, 
shorter,  or  longer  loops,  which  depend  toward  the  anterior  margin  (Fig.  531, 
E,  F).  The  two  descending  hranches  may  either  unite  directly  or  may  be 
joined  by  a  transverse  band ;  or  the  descending  branches  may  recurve,  continue 
upward  as  ascending  branches,  and  be  connected  posteriorly  by  a  transverse 
band.  In  the  Terebratellidae,  during  all  or  some  portion  of  the  animal's 
existence,  the  loops  are  attached  to  a  median  septum  by  outgrowths  from  the 
descending  lamellae  (Fig.  531,  6^).  In  the  Stringocephalidae  and  Megathyrinae 
(Fig.  531,  H)  the  descending  branches  are  parallel  to  the  lateral  margins  of 
the  Shell,  and  unite  along  the  median  line ;  but  in  some  degenerate  species 
a  remnant  of  the  loop  is  represented  by  a  transverse  band  situated  centrally 
on  the  median  septum.  The  entire  form  of  the  brachidia  is  manifestly 
dependent  upon  the  character  of  the  convolutions  of  the  fleshy  arms.  In 
recent  Hemithyris  (Fig.  531,  A)  the  brachia  form  hollow  spiral  cones,  and  if 
we  imagine  these  as  supported  by  a  calcareous  framework,  the  result  will  be 
a  form  of  support  like  that  seen  in  the  Atrypidae.  The  fleshy  arms  of  the 
Terebratellidae  are  continuous  with,  and  have  at  first  the  form  of  the  loop, 
but  later  develop  a  coiled  median  arm.  Here  the  loops  only  have  calcareous 
supports ;  but  in  the  Spiriferacea  the  entire  brachia  are  provided  with  an 
internal  calcareous  skeleton. 

The  changes  in  the  form  of  the  brachidia  in  the  Telotremata  during  the 
ontogenetic  stages  of  the  individual  furnish  very  important  data  in  regard 
to  the  relationships  existing  between  the  different  groups.  In  the  Spiri- 
feracea, not  only  does  the  number  of  convolutions  of  the  spirals  increase  with 
age,  but  the  brachidia  begin  with  Centronella-  and  Dielasma-\\\Q  loops,  from 
the  outer  ends  of  which  the  spires  are  developed.     Still  more  striking  are 


362  MOLLUSCOIDEA  phylum  v 

the  metamorphoses  which  the  loops  of  the  Terebratulacea  undergo.  According 
to  G^hlert  and  Beecher,  the  loop  of  the  living  austral  genus  Magellania  passes 
through  stages  which  correspond  successively  to  those  of  Gwynia,  Argyrotheca, 
Boitchardia,  Magas,  Magasella,  Terebratella  and  Magellania;  and  Friele  has 
shown  that  the  metamorphoses  of  the  loop  in  the  boreal  form  Macandrevia 
cranium  correspond  in  succession  to  the  genera  Platidia,  Ismenia,  Miiehlfeldtia, 
Terebratalia  and  Macandrevia. 

A  knowledge  of  the  character  of  the  brachidia  in  the  Spiriferacea  and 
Terebratulacea  is  almost  always  requisite  for  critical  generic  determinations. 
But  an  examination  of  the  interior  of  the  shell  in  fossil  Brachiopods  often 
involves  great  difficulties,  owing  to  the  infiltration  of  calcite,  or  the  filling  up 
of  the  shell  cavity  with  sediment.  Not  infrequently  the  shell  and  the 
brachidia  are  secondarily  replaced  by  silica ;  and  if  the  interior  filling  matter 
be  dissolved  away  by  dilute  hydrochloric  acid,  exquisite  preparations  may  be 
obtained,  often  revealing  the  minutest  details.  Sometimes  hollow  shells  are 
found,  in  which  the  brachidia  are  well  preserved,  but  these  structures 
generally  are  more  or  less  encrusted.  It  is  often  necessary  to  remove  the 
ventral  valve,  when  the  infiltrated  material  can  be  cut  away  by  the  use  of 
proper  tools.  Success  in  manipulations  of  this  kind  requires  not  only  con- 
siderable  dexterity,  but  the  conditions  of  preservation  must  have  been  very 
favourable.  The  brachidia  must  be  perfectly  preserved,  and  the  surround- 
ing  matrix  must  admit  of  being  removed  with  out  injury  to  the  specimen. 
When  other  expedients  fail,  recourse  can  still  be  had  to  polishing,  the  shell 
being  gradually  ground  down  by  abrasion  with  emery  powder  on  a  glass 
plate.  The  beaks  are  first  ground  away,  until  the  first  traces  of  the  crura 
appear;  the  surface  is  then  cleaned  and  kept  moistened  while  a  careful 
drawing  is  made.  Grinding  is  resumed  for  a  short  interval,  when  the 
surface  is  again  cleansed  and  drawn.  This  process  is  repeated  until  the 
sections  include  the  entire  brachial  support.  From  the  series  of  transverse 
sections  thus  obtained,  the  brachidium  can  be  ideally  reconstructed. 

The  spondylium  is  an  internal  ventral  plate  traversing  the  posterior 
portion  of  the  valve  (Fig.  585,  0).  On  the  superior  surface  of  the  plate  are 
inserted  the  adductors,  diductors  and  the  ventral  pedicle  muscles.  Beneath 
the  spondylium,  which  may  be  supported  by  a  median  septum,  are  situated 
the  reproductive  organs.  The  plate  is  homologous  with  the  solid  or  excavated 
platform  of  the  Atremata  (Trimerellidae  and  Lingulasmatidae). 

Soft  Parts  :  ManÜe. — Lining  the  entire  inner  surface  of  the  shell  is  a 
thin,  transparent  membrane,  which  appears  in  the  embryonic  condition  as 
two  distinct  lobes  of  the  thoracic  segment  in  the  Cephalula  stage.  This  is 
the  mantle  or  pallium,  which  is  primarily  concerned  in  the  secretion  of  the 
shell.  In  Crania  it  consists  of  three  layers  :  a  middle  cartilaginous,  an  inner 
ciliated  one,  and  an  outer  layer  of  cells.  The  layer  lying  against  the  surface 
of  the  shell  is  often  studded  with  minute  caeca  or  blind  tubes,  which  enter 
the  perforations  of  the  test.  The  mantle  (or  certain  of  its  layers)  is  folded 
upon  itself  at  various  points,  enclosing  cavities  or  pallial  sinuses,  which  contain 
the  circulating  fluids,  and  frequently  portions  of  the  genital  organs.  Distinct 
impressions  of  these  sinuses  are  often  observable  in  the  valves  of  both  recent 
and  fossil  specimens  (Fig.  532).  In  all  the  greater  sinuses  of  the  mantle,  in 
the  peri visceral  cavity,  and  in  the  cavernous  brachia  and  cirri,  occur  calcareous 
spicules  of  various  shapes.     These  are  especially  abundant  in  the  Thecidiidae, 


CLASS  II  BRACHIOPODA  363 

and  form  an  irregulär  mass  or  network.  They  appear  to  be  absent  in 
Magellania,  Terebratella  and  Lingula.  The  outer  margins  of  the  mantle  are 
thickened  and  set  with  numerous  chitinous,  simple 
or  barbed  setae,  sometimes  of  great  length. 

The  shell  cavity  is  divided  by  a  vertical  mem- 
branous  wall,  which  is  an  extension  of  the  mantle, 
into  two  regions  :  a  posterior,  or  visceral  cavity,  and 
an  anterior,  or  brachial-  cavity.  The  posterior  cavity 
contains  the  principal  viscera,  the  alimentary,  cir- 
culatory,  nervous  and  muscular  Systems.  The  an- 
terior Chamber  is  occupied  by  the  arms. 

Organs  of  the   Visceral  Cavity. — The  membranous  fig.  532. 

partition  is  pierced  centrally  by  the  oval  or  slit-like  camarophoHa  humUetonensis 
mouth,  from  which  the  digestive  tuhe  extends  back-  Enjand.  internal  mouXshowing 
wards  as  a  simple  or  bent  canal.  In  inarticulate  JXr  üSsonX  ^*"'*^  ^'""^^^ 
species,    the    alimentary  canal  is   very   long,  makes 

several  convolutions,  and  terminates  in  a  well-defined  anus,  situated  on  one 
side  of  the  animal.  In  the  Protremata  and  Telotremata  the  digestive  tube 
is  shorter  and  much  simpler  than  in  the  Atrernata  and  Neotremata.  The 
intestine  makes  a  single  convolution  and  terminates  blindly  in  the  living 
representatives  of  these  Orders,  being  surrounded  by  large  hepatic  lobes. 
In  many  Paleozoic  species  it  probably  did  not  terminate  blindly,  since  the 
intestine  passed  through  the  hinge-plate  by  a  central  foramen.  There  is  no 
heart,  circulation  being  apparently  maintained  by  the  cilia  lining  the  vas- 
cular  sinuses.  These  sinuses  pass  into  the  perivisceral  Chambers,  and  are 
developed  into  vascular  dilations  at  the  back  of  the  stomach  and  elsewhere. 
These  bodies  are  not  contractile,  and  their  function  is  unknown.  Two 
numerously  branched  vascular  trunks  diverge  from  the  anterior  portion  of 
the  perivisceral  Chambers,  traversing  the  mantle  in  either  valve  to  its 
margins,  and  several  others  pass  over  the  fleshy  brachia  for  their  entire 
length.  The  nervous  System  consists  of  a  circum-oesophageal  ring  on  which 
two  supra-oesophageal  ganglia  are  inserted.  From  the  swellings  of  the 
oesophageal  ring  (notably  from  that  on  the  lower  side),  nerve  fibres  are 
given  off  to  the  brachia,  muscles,  pedicle  and  the  two  lobes  of  the  mantle. 
In  adult  Brachiopods  sense  organs  are  not  known  with  certainty ;  but  in 
the  embryos  such  are  believed  to  be  present.  So  far  as  is  known  the 
sexes  are  always  separate.  The  sexual  organs  in  both  male  and  female 
are  located  essentially  alike,  and  have  a  paired  arrangement.  Generally 
they  occupy  the  main  trunks  ^of  the  vascular  sinuses,  but  may  extend  into 
the  visceral  Chamber,  or,  in  some  of  the  inarticulate  forms,  may  be  restricted 
to  the  latter. 

The  Brachial  Cavity. — The  greater  part  of  the  anterior  or  brachial  cavity 
is  occupied  by  the  spirally  enrolled  labial  appendages,  the  so-called  arms,  or 
brachia.  These  are  two  in  number,  one  at  each  side  of  the  mouth,  and  are 
of  extremely  delicate  Constitution  (Figs.  533,  534,  and  531,  ^).  The  tissue 
of  which  they  are  composed  is  essentially  cartilaginous,  and  is  traversed  by 
several  circulatory  canals  as  well  as  by  a  groove.  The'  outer  edges  of  the 
brachia  are  fringed  with  long  and  movable  cirri  or  tentacles,  by  means  of  which 
currents  are  set  up  that  conduct  small  food  particles  to  the  mouth.  The 
arms   are   frequently   supported   by   a   slender    calcareous  framework   called 


364 


MOLLUSCOIDEA 


PHYLUM  V 


the  brachial  supports,  or   hrachidia,  described  above.     There  are  no  special 
respiratory  organs,  the  blood  being  oxygenated  in  the  inner  surface  of  the 

mantle  and  in  the  spiral 
arms,  where  it  is 
brought  into  close  os- 
motic  relation  with  the 
water. 

Muscular  System. — 
By  means  of  muscles 
Brachiopods  are  en- 
abled  to  open  and  close 
their  valves,  and  to  a 
Median  verticai   limited  cxtcnt  can  pro- 


FiG.  533. 

Liothyrina  vitrea 
(Liunaeus).  Recent. 
Fleshy  brachia  simply 
recurved. 


Magellania  fla 


section,  slightly  enlarged.     d,  Spiral  brachia ;  li,  fm-^p     onri     rpfrnpt     fVip 

Fringed  brachial  marlin  ;  pr,  Cardinal  process ;  ^^^^®     ^^^    retract     tne 

^,  Alimentary  canal ;  v,  Mouth  ;  ss,  Septum  ;  a,  pediclc.       In    the  articu- 

Adductors ;  c,  c'  Diductors  (after  Davidson).  T    ,        c  /-r,      j 

late  lorms  (rrotremata 
and  Telotremata)  there  are  three  sets  of  muscles — namely,  the  diductors, 
which  by  contraction  open  the  valves ;  the  adduäors,  which  by  contraction 
close  the  valves  ;  and  the  pedide  muscles,  or  adjustors,  which  also  by  contrac- 
tion withdraw  the  pedicle.  The  points  of  attachment  of  these  muscles  leave 
more  or  less  distinct  impressions  in  the  valves  of  both  recent  and  fossil 
Brachiopoda,  and  the  subject  is  therefore  worthy  of  careful  examination. 


The  adductors,  or  closing  muscles,  are  attached  on  either  side  of  the  median  line 
in  the  dorsal  valve,  and  leave  two  elongate  scars  lying  immediately  to  the  right  and 
left  of  the  median  line,  enclosed  between  the  diductors  (Fig.  535,  B,  a).  These 
muscles  extend  almost 
directly  from  one  valve 
to  the  other,  and  as  eaeh 
muscular  band  is  once 
divided,  their  insertions 
on  the  dorsal  valve  are 
quadruple.  Their  im- 
pressions on  this  valve  are 
known  as  the  anterior  and 
posterior  adductors  (Fig. 
535,  A,  B,  a,  a). 

The  principal  diduc- 
tors, or  opening  muscles, 
originate  on  the  ventral 
valve  at  the  anterior  edge 
of   the  visceral  area,  and  ^^^'-  ^s^- 

.,■■  .1  r.      ,-1  Magellania  flavescens  (Val.).     Recent;  Australia  (after  Davidson).     A, 

on      eitner      Siae  OI      tue  Dorsal  valve.     B,  Ventral  valve.     D,  Deltidial  plates.     F,  Foramen.     S, 

median  line  •    the  scars    of  l^ooP«    P^>  Cardinal  process  ;  x,  Hinge-plate  ;    z,  Hinge-teeth  ;  a,   a',  Im- 

-  1     'i     •  11  pressions  of  adductors  ;  d,  rf',  Diductors  ;  jj,  p',  Pedicle  muscles. 

these  muscles  bemg  usually 

the  largest  and  deepest  of  any  in  the  animal.  They  taper  rapidly  in  crossing  the 
interior  cavity,  and  their  small  extremities  are  attached  to  the  anterior  portion  of 
the  cardinal  process  of  the  dorsal  valve,  There  are  also  inserted  on  the  cardinal 
process,  behind  the  principal  diductors,  two  mucli  smaller  muscular  bands,  which 
are  called  the  accessory  diductors.  Their  attachment  on  the  ventral  valve  is  repre- 
sented  by  two  feeble  scars  in  the  posterior  part  of  the  muscular  region,  but  these  are 
rarely  observable  in  fossil  specimens  (Fig.  535,  A,  B,  d). 


CLARS  II 


BRACHIOPODA 


365 


Wlien  a  fimctional  pedicle  is  present,  there  are  foimd,  in  addition  to  the  valvulär 
muscles,  two  pairs  (one  to  each  valve),  and  a  single  impaired  muscle ;  these  are 
attaclied  to  tlie  pedicle,  and  are  called  the  pedicle  muscles  (Fig.  535,  -B,^,  'p').  The  pair 
in  the  ventral  valve  originates  immediately  outside  of  and  posterior  to  the  adductors 
and  diductors  ;  the  pair  in  the  dorsal  valve  is  attaclied  behind  the  posterior  adductors  ; 
and  the  unpaired  muscle  lies  at  the  base  of  the  pedicle  in  the  ventral  valve.  Only 
the  latter  unpaired  band,  as  a  rule,  leaves  a  perceptible  scar  in  fossil  specimens. 

The  entire  muscular  System  in  the  Protremata  and  Telotremata  works  with  the 
utmost  precision.  The  cardinal  process  is  received 
between  the  teeth  of  the  ventral  valve  in  such  a 
manner  as  to  allow  the  dorsal  valve  to  swing  freely 
in  the  median  vertical  plane  as  on  hinges,  and  at 
the  same  time  prevents  motion  in  a  lateral  direc- 
tion,  The  diductors,  being  attached  to  the  cardinal 
process,  act  upon  a  lever  arm  when  they  contract, 
thus  opening  the  valves,  while  the  contraction  of 
the  adductors  serves  to  close  them  (Fig.  534). 

In  the  Atremata  and  Neotremata  the  muscles 
are  arranged  differently,  and  are  often  more  conipli- 
cated  and  numerous,  as  articulation  is  almost  never 
present  in  these  Orders.  The  greatest  complexity  is 
attained  in  Lingula  (Fig.  536),  because  these  animals, 
in  addition  to  the  absence  of  articulation,  slide  their 
valves  laterally. 

Ontogeny. — The  development  of    Brachio- 
pods  from  the  egg  to  maturity  may  be  divided 
into  two  periods:  {a)  stages  of  development  from 
the  egg  to  that  condition  in  which  the  animal  is  sheirwrth'^'pedicie,  Srai^'size.'   b\ 
recognisable  as  possessing  some  distinctive  class  JlTLfpre^SjT^^^ 

Characters  ;     and    {h)    from    the    first   Shelled    COn-    Protractors ;  p,  Retractors ;  o,  Pedicle 

dition,  or  protegulum,  to  maturity  and  old  age. 


Fig.  536. 


Our  knowledge  of  the  earliest  embryonic  conditions  is  restricted  to  Terehratulina^ 
Liothyrina,  Ärgyrotheca  and  Thecidea.  After  fertilisation  the  larvae  may  remain 
attached,  and  pass  their  early  stages  within  the  parent ;  or  they  may  develop  cilia 
before  segmentation,  and  be  set  free  in  the  pallial  Chamber  or  in  the  sea-water.  The 
free  larvae  swim  by  the  aid  of  cilia  with  a  twirling  motion.  There  are  five  well- 
marked  stages  of  development  before  the 
larvae  can  be  definitely  recognised  as 
Brachiopods.  These  are :  (1)  The  prot- 
emhryo,  which  includes  the  ovum  and  its 
segmented  stages  preceding  the  formation 
of  a  blastula,  or  primary  internal  cavity 


Fig.  538. 
Ärgyrotheca    neapolitana   (Schacchi).     A, 


Neo- 


Argyrotheca  iimpoUtana  (Schacchi).  Recent. 
A,  Protembryo;  iinsegmented  ovum.  B,  Prot- 
embryo;  ovum  composed  of  two  spheres.  C, 
Mesenibryo  ;  blastosphere.  7),  Metembryo  ;  gast- 
rula  (after  Shipley,  from  Reecher). 


embryo;  embryoof  twosegments.  ii,  Xeoembryo ; 
cephahila,  ventral  side,  showing  cephalic,  thoracic 
and  caudal  segments,  eye-spots,  and  bundles  of 
setae.  C,  Neoembryo ;  hiteral  view  of  completed 
cephalula  stage,  sliowing  extent  of  dorsal  (rf)  and 
ventral  (c)  mantle  lobes,  and  umbrella-like 
cephalic  segment.  {A  and  B  after  Kovalevski,  G 
after  Shipley;  all  reproduced  from  drawings  by 
Reecher.) 


366 


MOLLUSCOIDEA 


PHYLUM  V 


(Fig.  537,  Ä,  B) ;  (2)  the  mesemhryo,  or  blastosphere,  a  multi-segmented  larva  with  an 
internal  cavity  (Fig.  537,  G);  (3)  the  metembryo,  or  gastrula  stage  (Fig.  537,  D);  (4) 
the  neoembryo,  or  the  ciliated  Cephalula  stage,  which  consists  atjfirst  of  a  cephalic  lobe, 
bearing  eyes  in  Ärgyrotheca,  and  a  caudal  lobe,  to  which  is  added  later  a  thoracic 
Segment  carrying  four  biindles  of  setae,  while  at  the  same  time  the  dorsal  and  ventral 
sides  of  the  latter  segment  become  extended  over  the  caudal  lobe,  and  are  progres- 
sively  defined  as  two  lobes  (Fig.  538) ;  (5)  the  typemhryo,  or  larval  stage,  in  which 
the  dorsal  and  ventral  thoracic  lobes,  or  mantle,  fold  over  and  enclose  the  cephalic 
lobe  (Fig.  539,  B).  Upon  the  mantle  lobes,  either 
before  or  after  turning,  there  is  a  corneous  integument 
which  develops  into  the  protegulum  before  the  for- 
mation  of  the  true  shelL  The  caudal  segment  be- 
comes  the  pedicle,  and  may  in  this  stage  serve  to 
attach   the  larvae   to  foreign  objects,   or  the  pedicle 


Ärgyrotheca  neapolitana  (Schacchi).  A,  Neoembryo ;  completed 
cephalula  stage.  B,  Typembryo ;  transformed  larva  resulting  from 
folding  upwards  of  mantle  lobes  over  cephalic  segment ;  ad,  Muscles 
from  bundles  of  setae  to  sides  of  body  cavity  ;  di,  Muscles  from  dorsal 
to  Central  sides  of  body  ;  vp,  Muscles  from  ventral  side  of  body  to 
caudal  segment  or  pedicle  (after  Kovalevski,  from  Beecher). 


Fig.  540. 

ArgyrothecaneapoUtana(ßchsiCch.i). 
A,  Phylembryo  ;  Brachiopod  show- 
ing  Shell  (protegulum),  beginning  of 
tentacles  of  lophophore  (/),  obsoles- 
cence  of  eye-spots,  and  formation 
of  Oesophagus  ;  t,  Hinge-teeth  ;  vp, 
Ventral  pedicle  muscles.  B,  Nepio- 
nic  Brachiopod,  showing  distinct 
tentacles  of  lophophore,  mouth  and 
stomach,  and  transformation  of 
muscleg  from  typembryo ;  ad,  Ad- 
ductors ;  di,  Divaricators ;  vjj, 
Ventral  pedicle  muscles  (after 
Kovalevski,  from  Beecher). 


may  remain  undeveloped  for  a  time.  A  rudimentary  digestive  tract  is  present,  and 
also  four  pairs  of  muscles,  which  later  become  the  adductor,  diductor  and  ventral 
pedicle  muscles. 

In  the  phylembryo,  orsixth  stage  ofdevelopment,  the  embryonic  shell,  ov  protegulum, 

is  completed;  the  tentacular  lobes  of 
the  lophophore,  or  brachia,  appear ;  the 
four  bundles  of  setae  are  dehisced ;  ob- 
solescence  of  the  eyes  occurs,  as  well  as  the 
agreement  of  the  muscular  system  with 
that  in  adult  forms  (Fig.  540). 

The  protegulum  has  been  observed  by 


Fig.  541. 


Thecidea  (Lacazeiia)  mediterranea  (Risso).     Recent.  Beecher    in    many  genera     representiuff 

A,  Dorso- ventral    longitudinal    section  of  cephalula;  ..r,r,T.Ur    oll    fl,^    l^o^-  -p       -t  a    ^-i 

h,   Head;  d,   Dorsal   mantle  lobe;  v,   Ventral  mantle  ^l^^rly    all    the    leadmg    families     of    the 

lobe;  ds,  Beginning  of  dorsal  ya.ive;  dei,  Shell  piate  class,   and  therefore   it  may  be  inferred 

formmg  on  dorsal  side  of  body;  p,  Pedicle.    B,  Dorso-  4.1,    +    +t.  ,  .         *^  xni-ciicu 

ventral  longitudinal  section  of  typembryo ;  vs.  Ventral  '^"-^^    tue    protegulum    IS    common    tO    all 

valve;  hl,  Hinge-line  of  dorsal  valve.     C,  Adult  speci-  BmchioDods        Tt   1=1  <iPminh^nM'\or>  ^1.  o^rr.; 

men  seen  from  the  dorsal  side,  showing  ventral  area  and  -^^f  ^^^lopo^S.       It  IS  SemiCllCUlar  or  semi- 

deltidium.    (^  and  iJ  after  Kovalevski;  C  after  Beecher.)  elliptical   in    Outline,   with   a    straight    or 

arcuate  hinge-line,  and  no  cardinal  area. 

The   prototype  preserving  throughout    its  development   the    main   features    of  the 


CLASS  II       •  BRACHIOPODA  367 

protegulum,  and  showing  no  separate  or  distinct  stages  of  growtli,  is  represented  by 
tlie  genus  Paterina  (Fig.  543). 

So  far  as  observed,  the  protegulum,  or  Paterina  stage,  in  tlie  Atremata  and 
Telotremata  is  followed  by  tlie  Obolella  stage  of  nearly  circular  outline.  After  this 
stage,  specific  cliaracters  appear,  and  in  tlie  open  delthyrium  of  tlie  Telotremata  there 
are  usually  developed  the  first  rudiments  of  tbe  deltidial  plates.  In  the  Protremata, 
the  Paterina  stage  is  not  followed  by  the  Obolella  stage,  but  the  wide  delthyrium  of  the 
protegulum  is  at  once  affected  and  modified,  and  develops  into  the  deltidium.  In  the 
Acrotretacea,  belonging  to  the  Neotremata,  there  is  often  developed  a  homoeodeltidium, 
resulting  from  secretion  by  the  mantle,  and  therefore  of  different  origin  from  the  true 
deltidium  occurring  in  the  Protremata,  which  is  deposited  by  the  pedicle.  In  the 
Discinacea,  belonging  to  the  Neotremata,  the  pedicle  opening  is  an  open  notch  in  the 
posterior  margin  of  the  ventral  valve.  In  derived  forms  this  is  progressively  closed 
posteriorly ;  geologically  in  the  phylum,  and  ontogenetically  in  the  latest  derived 
genera  and  species. 

Habitat  and  Distribution.  —  Brachiopods  are  usually  gregarious  in 
habit,  often  growing  in  Clusters  attached  to  one  another.  This  is  not  only 
true  of  Recent  species,  but  of  Paleozoic  forms  as  well.  Brachiopods  are 
found  in  all  latitudes  and  at  all  depths,  but  are  largely  shallow-water  animals, 
for  of  the  living  species  71  per  cent  occur  between  the  strand-line  and  100 
fathoms.  Liothyrino,  wyvillii  was  dredged  from  the  enormous  depth  of  2945 
fathoms.  Terebratulina  caput-serpentis  ranges  from  a  few  fathoms  to  a  depth 
of  1170  fathoms. 

Brachiopods  are  most  abundant  in  warmer  seas,  the  Japanese  province  having 
twenty-nine  species.  As  a  rule,  those  occurring  in  cold  waters  are  not  found 
in  warm  waters.  Lingulids  and  Discinids  are  almost  restricted  to  the  strand- 
lines  in  warmer  waters  less  than  60  feet  deep.  Of  the  thirty-three  living 
genera,  at  least  60  per  cent  have  fossil  representatives.  Lingula  and  Crania 
have  lived  since  the  Ordovician  ;  since  the  Jurassic,  six  genera  have  continued, 
since  the  Miocene  one,  since  the  Pliocene  seven,  and  since  the  Pleistocene  three. 
Of  the  158  living  species  only  16  per  cent  occur  fossil,  and  but  five  are  as  old 
as  the  Eocene  and  Miocene.  Three  genera  are  confined  to  the  deep  sea,  and 
all  of  the  abyssal  forms  are  usually  thin-shelled,  brittle  and  translucent. 

Migration  of  Brachiopods  is  possible  only  during  the  early  larval  stages, 
and  then  to  a  very  limited  extent  among  the  articulate  forms.  Morse  observed 
that  Terebratulina  became  attached  in  a  few  days,  but  Müller  kept  Discinisca 
in  confinement  nearly  a  month  before  any  became  sessile. 

Colour. — The  shells  of  most  living  species  are  of  light  or  neutral  tints, 
white  or  horn-colour.  A  deep  orange-red  in  radiating  bands  or  in  solid  tints 
colours  some  species  (Terebratulina,  Kraussina,  etc.) ;  light  yellows,  deep  and 
light  shades  of  green  (Lingula),  black  in  bands  (Crania),  or  masses  (Rhynchonella) 
embellish  these  shells.  Even  among  the  fossil  species  traces  of  faded  colour- 
marks  are  occasionally  observed ;  Deslongchamps  has  described  them  among 
Jurassic  species,  Davidson  among  the  Carboniferous,  and  Kayser  has  found  a 
colour-marked  Rhynchonella  in  the  Devonian.  The  large  highly  ornamented 
species  of  Paleozoic  times,  with  their  external  sculpture  heightened  by  a 
brilliant  colouring,  must  have  been  objects  of  exquisite  beauty  (Hall  and 
Clarke). 

Classification. — The  Brachiopoda,  since  1858,  have  been  divided  by 
nearly  all  systematists  into  two  Orders,  based  on  the  presence  or  absence  of 


368  MOLLUSCOIDEA  phylum  v 

articulating  processes.  These  divisions,  "  Articules  and  Libres,"  were  recog- 
nised  by  Deshayes  as  early  as  1835,  but  not  until  twenty-three  years  later 
were  the  names  Lyopomata  and  Arthropomata  given  them  by  Owen.  These 
terms  have  been  generally  adopted  by  writers,  though  some  prefer  Inarticulata 
and  Articulata  Huxley,  or  Bronn's  Ecardines  and  Testicardines.  Bronn  (1862) 
and  King  (1873),  while  retaining  these  divisions,  considered  the  presence  or 
absence  of  an  anal  opening  more  important  than  articulating  processes,  and 
accordingly  proposed  the  terms  Pleuropygia  and  Apygia,  and  Tretenterata  and 
CUstenterata  respectively.  In  many  Paleozoic  rostrate  genera  of  Clistenterata, 
it  has  been  shown  that  an  anal  opening  was  also  present,  and  therefore  the 
absence  or  presence  of  this  organ  is  not  of  ordinal  value. 

The  first  attempt  to  construct  a  Classification  of  the  Brachiopods  was  that 
of  Leopold  von  Buch,  who  topk  for  his  principal  differential  characters  the 
conformation  of  the  umbonal  region,  the  presence  or  absence  of  a  pedicle,  the 
nature  of  the  deltidium,  and  the  external  form  and  ornamentation  of  the  shell. 
While  his  Classification  does  not  reflect  a  perfect  understanding  of  the  features 
in  question,  it  is  remarkable  that  von  Buch,  nearly  eighty  years  ago,  and 
Deslongchamps,  twenty-eight  years  later,  recognised  some  of  the  principles 
upon  which  the  Classification  of  the  Brachiopoda  is  now  established,  as,  for 
example,  the  nature  of  the  pedicle  opening. 

Up  to  1846  the  general  external  characters  of  the  Brachiopods  served 
the  majority  of  authors  as  the  essential  basis  for  generic  differentiation.  In 
that  year,  however,  King  pointed  out  that  more  fundamental  and  constant 
characters  exist  in  the  interior  of  the  shell,  a  fact  which  soon  came  to  be 
generally  recognised,  mainly  through  the  voluminous  and  admirable  contribu- 
tions  of  Thomas  Davidson. 

Waagen  in  1883  found  it  "absolutely  necessary  "  to  divide  Owen's  two 
Orders  into  seven  suborders.  The  basis  for  these  suborders  rests  on  no 
underlying  principle  of  general  application,  and  yet  five  of  these  divisions  are 
of  permanent  value,  for  each  contains  an  assemblage  of  characters  not  common 
to  the  others. 

No  Classification  can  be  natural  and  permanent  unless  based  on  the  history 
of  the  class  (chronogenesis)  and  the  ontogeny  of  the  individual.  However,  as 
long  as  the  structure  of  the  early  Paleozoic  genera  remained  practically  un- 
known,  and  the  ontogeny  wholly  unrevealed,  nothing  of  a  permanent  nature 
could  be  attempted.  In  the  excellent  volume  by  Hall  and  Clarke  (Palaeontology 
of  New  York,  vol.  viii.,  1892-95),  the  great  majority  of  the  Paleozoic  genera 
are  clearly  defined.  The  ontogenetic  study  of  the  Paleozoic  species  was 
initiated  in  1891  by  Beecher  and  Clarke,  followed  by  Beechßr,  and  more 
recently  by  Schuchert ;  and  their  results  combined  with  those  derived  from 
the  study  of  the  development  of  some  living  species,  such  as  have  been 
published  by  Kovalevski,  Morse,  Shipley,  Brooks,  (Ehlert,  Beecher  and 
others,  confirm  the  conclusion  reached  through  chronogenesis.  Moreover,  the 
application  by  Beecher  of  the  law  of  morphogenesis,  as  defined  by  Hyatt, 
and  the  recognition  and  establishment  of  certain  primary  characters  have 
resulted  in  the  discovery  of  a  fundamental  structure  of  general  application  for 
the  Classification  of  these  organisms.  It  has  for  its  foundation  the  nature  of 
the  pedicle  opening  and  the  stages  of  shell  development.  On  this  basis 
Beecher  (1891)  has  divided  the  class  into  four  Orders:  the  Atremata,  Neo- 
trematay  Protremata  and  Telotreiaata. 


CLASS  II  BRACHIOPODA  369 

,  The  nature  of  the  pedicle  opening  being  employed  for  ordinal  divisions, 
persistent  internal  characters  of  the  shell  are,  as  a  rule,  used  for  superfamily 
purposes.  Such  are  the  presence  or  absence  of  a  spondylium,  brachial  supports, 
etc.  Family  divisions  are  based  upon  a  combination  of  external  and  internal 
generic  characters,  such  as  the  outer  form,  nature  and  position  of  muscles, 
internal  plates,  etc. 

No  division,  however,  has  any  value  unless  the  group  contains  forms  of 
but  one  phylum,  since  a  phylum  or  line  of  descent  cannot  originate  twice. 
However,  it  happens  that  the  same  or  nearly  the  same  combination  of  mature 
characters  is  developed  along  different  lines  (homoeomorphy) ;  and  when  this 
occurs  the  ontogeny  will  show  it.  It  is  therefore  not  correct  to  group  different 
Stocks  under  one  and  the  same  genus.  For  instance,  the  family  Terebratellidae 
probably  divided  during  early  Mesozoic  times,  one  stock  drifting  into  boreal 
and  another  into  austral  regions.  These  two  Stocks  agree  structurally  in  the 
earliest  shelled  condition  and  also  at  maturity ;  but  between  these  two  stages 
of  development,  the  austral  group  (Magellaniinae)  passes  through  a  different 
series  of  loop  metamorphoses  from  the  boreal  one  (Dallininae).. 

It  was  by  the  application  of  the  above-mentioned  principles  that  Schuchert, 
in  1893,  arranged  all  the  genera  of  Brachiopoda  under  the  four  Orders 
instituted  by  Beecher.  Further  attention  has  since  been  given  to  this  subject 
by  the  same  writer,  and  the  arrangement  now  offered  combines  the  brilliant 
results  obtained  by  Charles  D.  Walcott  in  his  studies  of  the  Cambrian  forms 
of  all  lands,  and  the  important  work  of  S.  S. '  Buckman,  relating  to  the 
Brachiopods  of  Great  Britain. 

Order  1.     ATRBMATA  Beecher. 

This  Order  includes  primitive  inarticulate,  corneous  or  calcareophosphatic 
Brachiopoda,  with  the  pedicle  usually  emerging  freely  between  the  two  valves. 
Growth  takes  place  mainly  around  the  anterior  and  lateral  margins. 
Delthyrium  or  pedicle  aperture  originally  unmodified,  in  later  genera  modified 
by  homoeodeltidia  and  pseudochilidia,  or  by  thickened,  striated  and  more  or 
less  furrowed  or  even  cleft  vertical  cardinal  margins,  the  ventral  cleft  in  most 
specialised  forms  tending  to  enclose  the  pedicle  and  finally  to  restrict  it  to 
the  ventral  valve ;  when  completely  restricted  the  genera  are  referred  to  the 
Order  Neotremata.  Specialised  forms  tend  to  develop  rudimentary  articula- 
tion  or  muscle  platforms.  The  three  other  Orders  of  Brachiopods  have 
arisen  from  the  Atremata. 

Superfamily  1.     RUSTELLACEA  Walcott. 

Primitive,  thicJc-shelled,  corneous  or  calcareo-phosphatic  Atremata,  developing  more 
or  less  of  homoeodeltidia  and  pseudochilidia.  Muscle  scars  and  vascular  sinuses  as  a 
rule  not  well  defiiied  in  the  shell.  Out  of  this  stock  arose  the  Oholacea  and  Kutor- 
ginacea.     Cambrian  and  Ordovician. 

Family  1.     Rustellidae  Walcott. 

Primitive  Rustellacea  with  the  pedicle  aperture  of  hoth  valves  small,  more  or  less 
open,  and  not  much  modified  by  homoeodeltidia  or  pseudochilidia.  Muscle  scars  and 
vascular^ sinuses  not  well  defined  in  the  shell.     Lower  Cambrian. 

VOL.  I  2  B 


370 


MOLLUSCOIDEA 


THYLUM  V 


liustella    Walcott    (Fig.    542).     The   most    primitive   known   Brachiopod. 
Lower  Cambrian  ;  Vermont. 

Family  2.     Paterinidae  Schuchert. 

Progressive    Rustellacea    with    the  pedide    aperture   more   or    less    closed    hj 
homoeodeltidia  and  pseudochilidia.     Cambrian. 

Paterina     Beecher     (Fig.     543).       Surface     concentrically      ornamented. 


Fig.  542. 

Rustella  edsoni  Walcott.  Lower  Cam- 
brian ;  Vermont.  A,  Ventral  valve  sliow- 
ing  pedicle  furrow  (j))-  B,  Cardinal 
View  showing  tlie  open  and  unmodified 
pedicle  opening.     i/i  (after  Walcott). 


>^-^, 


U 

9 


Fig.  ,543. 

Paterina  superha  Walcott.  Middle  Cambrian  ;  Vermont. 
A-C,  Views  of  the  ventral  valve  showing  the  large  convex 
homoeodeltidium.  D,  Exterior  of  dorsal  valve.  '■^/.^  (after 
Walcott). 


Subgenera  :  Micromitra  Meek;  and  Iphidella  Walcott  (Iphidea  Billings  1872,  non 
Baly  1865).  Shell  in  the  former  more  or  less  ornamented  by  crenulated 
concentric  lines,  while  the  latter  has  diagonally  intersecting  rows  of  pits. 
Lower  and  Middle  Cambrian ;  North  America. 

Volhorthia  von  Möller.  A  globose  form  of  Paterina,  with  well-developed 
pseudodeltidia.     Ordovician ;  Esthonia. 

Mickwitzia  Schmidt.  Very  large  round  forms  with  more  or  less  ornate 
exteriors.  Lower  Cambrian ;  Esthonia,  Sweden,  America.  Causea  Wiman 
is  regarded  by  Walcott  as  probably  identical  with  Mickwitzia,  Lower 
Cambrian ;  Sw^eden. 


Superfamily  2.     KÜTORGINACEA  Walcott  and  Schuchert. 

Progressive,  thick-sheUed,  almost  calcareous  atrematous-like  shells,  tending  to  he 
transverse  and  developing  rudimentary  articulation,  more  or  less  rudimentary  cardinal 
areas,  homoeodeltidia  and  muscle  scars  prophetic  of  the  Protremata.  Derived  out  of 
Rustellacea.     Cambrian. 


Family  1.     Schuchertinidae  Walcott. 

Primitive  round  Kutorginacea  with  small  cardinal  areas.  Externally  like  Obolus, 
with  an  open  subtriangular  delthyrium  which  apparently  is  without  a  homoeodeltidium. 
Muscle  scars  and  vascular  markings  prophetic  of  the  Billingsellidae  of  the  Protremata, 
Cambrian. 

Schuchertina  Walcott  (Fig.  544).     Middle  Cambrian  ;  Montana. 


Family  2.     Kutorginidae    Schuchert. 
Progressive    transverse   Kutorginacea   with   rudimentary   cardinal   areas,    great 


CLAss  II  BRACHIOPODA  37 1 

delthyrial  opening,  rudimentary  articulation  and  immature  homoeodeltidia.     Muscle 
scars  prophetic  of  the  Strophomenacea  of  the  Protremata.     Cambrian. 

A  B 


l'Ki. '.J44. 


Fig.  545. 


^,  ,     ,     ,.             ,    .    w  ,     ..    ,r-,j,    ^  Kutonßna  cAngulatuBm.    Lo wer  Cambrian  ;  Vermont. 

bckuchertina  amhna  Walcott.  Middle  Cambrian  ;  A,  Interior  of  ventral  valve.     B,  Siele  view  of  conjoined 

near  Neihart,  Montana.  ^,  Interior  of  ventral  valve.  valves.     C,   Interior  of  dorsal  valve;  h,   Central  scars- 

L,  Interior  of  dorsal  valve  (after  Walcott).  j,  Anterior  lateral  scar ;  s,  Median  septum  (after  Walcott). 

Kutorgina  Billings  (Fig.  545).  Lower  Cambrian;  North  America  and 
Sardinia. 

Superfamily  3.     OBOLACEA  Schuchert. 

Derived  in  Eustellacea.  Progressive,  thick-shelled,  calcareo-phosphatic  or  corneous 
Atremata  without  homoeodeltidia  or  pseudochilidia. .  Bounded  or  linguloid  in  outline, 
more  or  less  lens-shaped,  and  fixed  hy  a  short  pedicle  throughout  life  to  extraneous 
objeds.     Cambrian  to  Silurian. 

Family  1.     Ourticiidae  Walcott  and  Scbuchert. 

Primitive  Obolacea  with  well-deßned  pedicle  aperture  common  to  both  valves. 
Interior  characters  mucli  as  in  Obolidae.     Middle  Cambrian. 

Curticia  Walcott.     Middle  Cambrian  ;  Wisconsin  and  Minnesota. 

Family  2.     Obolidae  King. 

Derived,  progressive  Obolacea  with  thicJcened,  striated,  vertical  cardinal  areas 
traversed  by  pedicle  grooves.  Muscles  and  vascular  trunks  strongly  impressed  in  the 
valves.     Cambrian  and  Ordovician. 

Subfamily  A.     Obolinae;  Dali. 

Primitive  Obolidae  with  the  pedicle  grooves  more  or  less  shallow  oi'  deeply  rounded, 
but  never  tending  to  form  a  sheath  or  to  restrict  the  pedicle  opening  entirely  to  the 
ventral  valve.  The  most  abundant  Brachiopods  of  the  Cambrian,  vanishing 
with  the  Ordovician. 

Obolus  Eidhwald  ( Ungula  Pander  ;  Ungulites  Bronn ;  Euobolus  Mickwitz) 
(Fig.  546).  More  or  less  rounded  Obolids.  Widely  distributed  in  Europe 
and  America.  The  following  subgenera  are  recognised  by  Walcott :  Broeggeria 
Walcott,  Upper  Cambrian,  England;  Mickwitzella  Walcott  (Thysanotus  Mickwitz, 
non  Alt.  1860),  Ordovician,  Esthonia;  Acritis  Volborth  (Aulonotreta  Kutorga 
1848,  errdre  1847),  Ordovician,  Esthonia;  Schmidtia  Volborth,  Ordovician, 
Esthonia  ;  Palaeobolus  Matthew,  Cambrian,  eastern  Canada ;  Fordinia  Walcott, 
Middle  Cambrian,  Utah ;  Lingulobolus  Matthew  {Sphaerobolus  Matthew), 
Upper  Cambrian,  eastern  Canada ;  Westonia  Walcott  (has  transversa  parallel 
ornamentation),  Middle  Cambrian,  Wyoming,  Utah  and  Idaho. 


372 


MOLLUSCOIDEA 


PHYLÜM  V 


Helmersenia    Paiider.      Yery  small    Obolids    with   a    pustulose    or    spiny 
surface.     Lower  Ordovician  ;  Esthonia. 

Lingulella  Salter  (Eooholus  Matthew)  (Fig.  547).  More  or  less  elongate 
Obolids.  Widely  distributed  throughout  the  world.  The  following  are 
subgenera:  Leptemholon  Mickwitz,  a.nd  Lingulepis 
Hall  (decidedly  elongate  Obolids).  '"^Jk  P 

j 

„ . -,  . . . ;_-_. .  p"^ 

c 


Fig.  546. 

O&oZtts  ma^MiaZis  Hall.  Middle  Cambrian  ;  Minnesota.  J,  Ex- 
terior  of  ventral  valve.  B,  Interior  of  saine.  C,  Interior  of 
dorsal  valve ;  a,  Filling  of  pedicle  furrow ;  c,  Areaof  outside  lateral 
scars  ;  Ä,  Central  scars  ;  i,  Transmedian  lateral  scars  ;  j,  Anterior 
lateral  scars  ;  ps,  Parietal  band ;  v,  Area  of  visceral  cavity  ;  vs, 
Vascular  sinus  with  outside  and  inside  vascular  branches  (after 
Walcott). 


Fig.  547. 

Lingulella  acutangulus  (Roemer). 
Upper  Cambrian  ;  Texas.  A,  Interior  of 
ventral  valve.  />',  Interior  of  dorsal 
valve  ;  g,  Umbonal  scar  ;  h,  Central  scar ; 
i,  Transmedian  lateral  scar ;  j,  Anterior 
lateral  scars ;  l,  Outside  lateral  scars  ;  p, 
Pedicle  furrow  ;  ps,  Parietal  band  ;  pvs, 
Vascular  branches  ;  s,  Median  septum ; 
X,  Cordiform  cavity;  z,  Vascular 
branches  (after  Walcott). 


Delgadella  Walcott.  Has  thickened  internal  margins.  Lower  Cambrian 
of  Portugal. 

Leptoholus  Hall.  Yery  small  Lingulellids  of  the  Ordovician  of  North 
America,  in  which  the  interiors  are  marked  by  two  or  three  diverging, 
slightly  elevated  septa,  which  occasionally  are  somewhat  bifurcated  terminally. 

Paterula  Barrande  (Cydus  Barrande,  non  de  Koninck  1841).  Closely  related 
to  Leptoholus,  but  the  inner  margins  of  the  valves  are  thickened.  Ordovician ; 
Bohemia  and  North  America. 

(?)  Spondylobolus  M'Coy.  Generic  characters  not  well  known.  Ordovician  ; 
Ireland. 


Subfamily  B.     Neobolinae  Walcott  and  Schuchert. 

Progressive  OboUdae  with  posterior  platforms,  to  which  were  prohably  attached  the 
central,  outside  and  middle  lateral  muscles.  Seems  to  have  arisen  in  thick-shelled 
Middle  Camhrian  Obolus,  and  is  transitional  to  the  platform-bearing  Trimerellids. 
Middle  Cambrian. 

Neobolus  Waagen  {Lakhmina  (Ehlert,  and  Davidsonella  Waagen,  non  Mun.- 
Chalmas  1880).     Middle  Cambrian  of  India. 


Fk; 


Elkania  desiderata  (Bill.).  Upper 
Cambrian;  Quebec.  J^,  Interior  of  ven- 
tral valve.  B,  Interior  of  dorsal  valve  ; 
Ji,  Central  scars  ;  i,  Transmedian  lateral 
scars ;  j,  Anterior  lateral  scars  ;  v,  Pos- 
terior lateral  scars  ;  p,  Platform  with 
muscle  scars ;  x,  Vascular  areas  in  front 
of  platform  (after  Walcott). 


Subfamily  C.     Elkaniinae  Walcott  and  Schuchert. 

Divergent  OboUdae  with  posterior  or  marginal 
platforms,  to  which  were  attached  the  central,  outside 
and  middle  lateral  muscles.  Not  in  lineof  develop- 
ment  to  Trimerellids.     Cambrian. 

Elkania  Ford  {Billingsia  Ford  1886,  non  de 
Koninck  1876)  (Fig.  548).  Cambrian;  North 
America. 


CLASft  II  BRACHIOPODA  373 

Subfamily  D.     Biciinae  Walcott  and  Schuchert. 

Progressive  Obolidae  with  the  pedicle  restrided  to  the  ventral  valve  and  more  or 
less  endosed  by  a  pedide  tuhe.  Articulation  rudimentary.  Out  of  ihis  stock  have 
arisen  the  Oholellidae  of  the  Neotremata.     Cambrian. 

Bida  Walcott.  Lower  Cambrian  of  Quebec  and  New  York.  Dicellomus 
Hall.     Middle  Cambrian  of  North  America. 


Family  3.     Trimerellidae  Davidson  and  King. 

Large,  thick-shelled,  inequivalved  Obolacea,  with  the  ventral  cardinal  area  usually 
very  prominent,  triangulär  and  transversely  striated.  Adjnstor  and  anterior  addudor 
musdes  elevated  upon  solid  or  excavated  platforms.     Ordovician  and  Silurian. 

Dinobolus  Hall  (Conradia  Hall ;  Obolellina  Billings).  Cardinal  area  not  so 
prominent  as  in  the  other  genera  of  this  family.  Platform  small,  with  abruptly 
conical  vaults.  Ordovician  and  Silurian ;  North  America,  Great  Britain, 
Bohemia,  Gotland  and  Esthonia. 

Monomerella  Billings.  Similar  to  Trimerella,  with  well-developed  platforms 
in  both  valves ;  that  of  the  dorsal  valve,  however,  but  slightly  excavated. 
Silurian ;  North  America,  Gotland  and  Livonia. 

Trimerella  Billings  (Gotlandia  Dali)  (Fig.  549).     Platforms  long,  narrow. 


Fio.  549. 
TriTnerella  Undstroemi  (Dali).     Silurian  ;  Gotland,  1/2-     ^.  Shell  seen  from  the  dorsal  side.    B,  C,  Interior 
of  dorsal  and  ventral  valves  respectively.    D,  Internal  mould.    (A  and  B  after  Davidson ;  C  and  D  after 

Lind  ström,) 

well  developed  and   doubly   vaulted.     Dorsal  beak   often   thickened  into  a 
prominent  apophysis  extending  against  the  cardinal  slope  of  the  ventral  valve. 
Silurian ;  North  America,  Gotland  and  Faröe. 
Bhinobolus  Hall.     Silurian ;  North  America. 

Superfamily  4.     LINGULACEA  Waagen. 

Elongate,  thin-shelled,  corneous,  burrowing  Atremata,  derived  out  of  Obolinue, 
with  a  more  or  less  long,  worm-like,  tubulär,  flexible  pedide.     Ordovician  to  Recent. 

Family  1.     Lingulidae  Gray. 

Attenuate,  sub-quadrate  or  spatulate,  almost  equivalved  Lingulacea,  with  a  more 
or  less  long,  tubulär,  flexible  pedide.     Musdes  highly  differentiated  and  consisting  of 


374 


MOLLUSCOIDEA 


PHYLUM  V 


six  pairs,  two  of  addudors,   and  four  of  sliders   or  adjustors.     Ordovician    to 
Recent.     Maximum  development  in  Ordovician,  declining  after  Devonian  time. 

Pseudolingula  Mickwitz.     Has   a   ventral    pedicle   groove   and   a    pair   of 
umbonal  muscles.     Ordovician  and  Silurian ;  Europe  and  America. 

Lingula  Bruguiere  (PAare^ra  Bolton ;  Lingularius  Dumeril);  (subgen.  (r/ossma 

Phill.)  (Figs.  550,  551).  Shell  thin,  usually 
compressed,  glistening,  generally  smooth,  or 
with  fine,  concentric,  more  rarely  with  both 
concentric  and  radial  Striae ;  broad  over  the 
pallial  region,  tapering  more  or  less  toward  the 
beaks.  Ordovician  to  Recent.  Maximum 
development  in  Silurian  and  Devonian. 

Glottidia   Dali.     Like    the    preceding,  but 

interior  of  ventral  valve  with  two  septal  ridges 

diverging  from  the  beaks.     Dorsal  valve  with 

a  Single  median  ridge.    Recent;  American  seas. 

Dignomia  Hall.     Both  valves  with  median 

septal    ridges ;    that    of    the 

dorsal    valve     stronger,     and 

flanked    by    two   submarginal 

diverging    ridges,   which    cor- 

respond  in  position  to  grooves 

in  the  ventral  valve.     Middle 

Devonian  ;  North  America. 

Barroisella  Hall  andClarke. 

Silurian   and    Devonian ;    North 


Lingula  anatina  Brug.    Recent.    A,  Shell 
with  pedicle.     B,  Interior  of  ventral  valve. 


551. 


Lingula  lewisii  Sow. 
Sihman  ;  Gotland. 


Lingulids   with   rudimentary   articulation. 
America ;  (?)  Bohemia. 

Thomasina  Hall  and  Clarke.  Lingulids  with  the  posterior  margin  of  the 
ventral  valve  notched,  and  with  two  conspicuous  articulating  processes. 
Silurian ;  France. 

Lingulipora  Girty.  Lingulids  with  a  punctate  shell.  Devonian  and 
Lower  Carboniferous  ;  North  America. 


Family  2.     Lingulasmatidae  Winchell  and  Schuchert. 

Platform-hearing  Lingulacea  derived  through  Lingulidae.  Ordovician  and 
Silurian. 

Lingulops  Hall.  Small  Lingulids  with  narrow,  depressed,  not  excavated 
platforms.     Ordovician  and  Silurian  ;  North  and  South  America. 

Lingulasma  Ulrich  (Lingulelasma  Miller).  Large  thick-shelled  Lingulids 
with  very  prominent,  slightly  excavated  platforms.  Ordovician  ;  North 
America ;  (?)  England. 


Order  2.     NEOTREMATA  Beecher. 

Derived  and  specialised  inarticulate  Brachiopoda,  probably  developed 
through  Biciinae  of  the  Atremata.  Shells  as  a  rule  more  corneous  than 
calcareous,  more  or  less  cone-shaped,  with  the  pedicle  emerging  through  a 
Perforation  or  sheath  in  the  ventral  valve,  or  through  a  triangulär  more  or 


CLASö  II  BRACHIOPODA  375 

less  open  cleft  during  life,  or  only  so  in  the  youngest  shelled  stages,  after 
which  the  ventral  valve  may  become  cemented  to  foreign  objects.  Pedicle  in 
geologically  younger  forms  often  modified  by  a  listrium.  Homoeodeltidia  and 
pseudochilidia  as  a  rule  not  well  developed. 

Superfamily  1.     SIPHONOTRETACEA  Walcott  and  Schuchert. 

Primitive,  thicJc-shelled,  calcareous  or  corneous,  obolid-like  Neotremata,  with  the 
pedicle  passing  through  a  ventral  sheath,  the  aperture  of  which  may  remain  apical 
and  circular  in  outline  and  posterior  to  the  protegulum,  or  may  become  elongate 
through  resorption  by  passing  anteriorly  through  the  'protegulum  and  umbo  of  the 
shell.  Ä  listrium  is  not  developed.  Dorsal  protegulum  marginal.  Cambrian  to 
Silurian. 

Family  1.     Obolellidae  Walcott  and  Schuchert. 

Primitive  Siphonotretacea  with  the  pedicle  emerging  through  a  small  circular 
Perforation  in  the  apex  of  the  ventral  valve  posterior  to  the  protegulum.  Derived  out 
of  atrematous  Biciinae.     Cambrian. 

Obolella  Billings  (Fig.  552).  Small,  oval  or  round,  thick  shells  resembling 
Obolids  but  with  a  pedicle  tube  instead  of  an  open  furrow.  Lower  Cambrian 
of  North  America  and  Sweden.  The  subgenus  Glyptias  Walcott,  has  trans- 
verse  parallel  surface  sculpturing.     Lower  Cambrian  ;  Sweden. 


i  '^> :  A- 


Fig.  552. 

Obolella    atlantica    Walcott.      Lower 
Cambrian ;  Canada.      A,   Ventral  valve        ^ 
showing  vascular  sinuses  and  fiUiug  of  „       re« 

pedicle   foramen  (/)).     B,   Side   view  of  *  '"•  ^"'*- 

same.     (',   Dorsal  interior  showing  the  A-C,  Sijihonotreta  verrucosa  Vern.     Middle  Ordovician ; 

striated  cardinal  area(a)and  moulds  of  Esthonia.     D,  S.  ungtdculataEichw.,  showing  the  internal 

the  lateral  scars  (i)  (after  Walcott).  opening  of  the  pedicle  aperture  (after  Walcott). 

Botsfordia  Matthew  (Mobergia  Redlich).  Like  Obolella  but  with  a  highly 
Ornate  papillose  surface.     Cambrian  ;  North  America. 

Schizopholis  Waagen.  Middle  Cambrian  of  India.  (?)  Quebecia  Walcott. 
Lower  Cambrian  of  eastern  Canada. 

Family  2.     Siphonotretidae  Kiitorga. 

Progressive  Siphonotretacea  with  the  circular  or  elongate  pedicle  opening  at  the 
apex  or  passing  by  resorption  anteriorly  through  the  protegulum  aiul  umbo  of  the 
shell.     Cambrian. 

Siphonotreta  de  Verneuil  (Fig.  553).  Large  and  elongate  forms  in.  which 
the  pedicle  sheath  is  long  and  well  developed,  external  aperture  small  and 
circular.  External  surface  with  hollow  spines,  though  rarely  preserved ; 
shell  substance  punctured  by  radiating  and  branching  tubules.  Ordovician 
und  Silurian  ;  Europe  and  (?)  North  America. 


376 


MOLLUSCOIDEA 


PHYLÜM  V 


Schizambon  Walcott  (Schizamhonia  Q^hlert).  Small  spiniferous  Siphono- 
tretids  with  much  of  the  pedicle  sheath  open  as  a  cleft  on  the  outside. 
Upper  Cambrian  and  Ordovician ;  America  and  Russia. 

Trematobolus  Matthew  {ProtosipJion  Matthew).  With  rudimentary  articu- 
lation  and  lamellose  exterior.  Lower  and  Middle  Cambrian  ;  California  and 
New  Brunswick. 

Yorkia  Walcott.  The  oldest  form  of  the  family.  Concentrically  striated 
exterior.  Lower  Cambrian  of  eastern  North  America.  Dearhornia  Walcott. 
Middle  Cambrian ;  Montana. 

Keyserlingia  Pander.  Thick-shelled  form  with  decided  muscular  impres- 
sions  and  median  septa  in  both  valves.     Lower  Ordovician ;  Esthonia. 


Superfamily  2.     ACROTRETACEA   Schuchert. 

Progressive  Neotremata  with  corneous  or  calcareo-corneous  shells  that  are  more  or 
less  circular  in  outline  and  from  highly  conical  to  depressed  in  form.  The  pedicle 
opening  is  a  simple,  circular,  more  or  less  conspicuous  Perforation  through  the  apex 
of  the  ventral  valve,  and  is  situated  posterior  to  the  protegulum.  A  listrium  is  not 
developed.  A  false  cardinal  area  is  often  present.  Dorsal  protegulum  7tiarginal. 
Cambrian  to  Silurian. 


Family  1.     Acrotretidae    Schuchert. 

Same  characters  as  superfamily.  The  large  and  depressed  forms  are  of  the 
suhfamily  Acrothelinae,  white  the  small  forms  with  more  or  less  high  ventral  valves 
are  of  the  Acrotretinae.     Cambrian  to  Silurian. 


Suhfamily  A.     Acrothelinae  Walcott  and  Schuchert. 


Acrothele  Linnarsson  (Fig.  554). 
cl 


Cambrian ;  North  America  and  Europe. 
Subgenus  :  Redlichella  Walcott. 
>  Middle  Cambrian  ;  Sweden. 

Discinolepis  Waagen.  Middle 
Cambrian  ;  India. 


Fig.  554. 


Acrothele  {Redlichella)  granulata  (Linnarsson).  Middle  Cam- 
brian ;  Sweden.  A,  Ventral  valve  with  its  minute  pedicle  foramen. 
B,  Dorsal  exterior.  C,  Acrothele  matthewi  (Hartt),  showing  vas- 
cular  Sinus  (vs).  Middle  Cambrian  ;  New  Brunswick  (after 
Walcott). 

A 


Suhfamily  B.     Acrotretinae 
Matthew. 


B 

V5. 


3  ^•f\^§ 


A  false  cardinal  area  often 
present. 

Acrotreta  Kutorga  (Linnars- 
sonia  C.  D.  Walcott)  (Fig.  555). 
Widely  distributed  throughout 
the  Cambrian  and  rarely  in 
the  Ordovician  of  Europe  and 
North  America. 

Acrothyra  Matthew.     Ven- 
tral   valve    often    excessively 
high  and  oblique  or  elongate  in  outline.     Middle  Cambrian  ;  New  Brunswick. 
Conotreta  Walcott.     Highly  conical  shells  with  the  ventral  interior  marked 
by  a  number  of  radiating  ridges.      Ordovician  and  Silurian  ;  North  America. 


Fig.  555. 

A-C,  Acrotreta  schmalensii  Walcott.  Middle  Cambrian ; 
Sweden.  A,  Three  views  of  the  ventral  exterior,  B,  Ventral 
interior  with  vascular  sinus  (vs).  C,  Dorsal  interior.  D,  E, 
Acrotreta  subconica  Kutorga.  Ordovician ;  Esthonia.  Cardinal 
view  and  dorsal  valve  (after  Walcott). 


CLASs  11  BRACHIOPODA  377 

Linnarssonella  Walcott.     Middle  Cambrian  ;  North  America. 

Discinopsis  Matthew.  Has  marked  ventral  vascular  sinuses.  Middle 
Cambrian ;  New  Brunswick. 

(?)  Mesotreta  Kutorga.  Ventral  valve  spinöse.  Basal  Ordovician ; 
Esthonia. 

Superfamily  3.     DISCINACEA   Waagen. 

Specialised  Neotremata  with  phosphatic  shells^  a  listrium  modifying  the  pedicle 
slit,  and  without  pseudodeltidia  and  false  cardinal  areas.  Dorsal  protegulum 
usually  subcentral.     Ordovician  to  Recent. 

Family  1.     Trematidae    Schiichert. 

Primitive  Discinacea,  in  which  the  posterior  margin  of  the  ventral  valve  has  a 
triangulär  pedicle  notch  throughout  life.  A  listrium  is  usually  present.  Ordovician 
to  Coal  Measures. 

Trematis  Sharpe  {Orhicella  d'Orb.  1847,  non  Dana  1846).  Ventral  valve 
unevenly  convex,  more  or  less  depressed  over  the  posterior  region.  Pedicle 
fissure  large,  extending  from  the  apex  to  the  posterior  margin.  Dorsal  valve 
evenly  convex,  and  sometimes  with  incurved  beak ;  posterior  margin  much 
thickened,  and  broadly  grooved  for  the  passage  of  the  pedicle.  Surface  of 
both  valves  covered  with  punctures  or  small  pittings  arranged  either  in 
quincunx  or  in  radiating  rows.  Ordovician  and  (?)  Silurian ;  North  America 
and  (?)  Europe. 

Eunoa  Clarke.  Very  large,  depressed,  thin  shells,  with  fine  concentric 
lines.     Pedicle  notch  very  large.     Ordovician  ;  New  York. 

Schizocrania  Hall  and  Whitfield.  Ventral  valve  flat  or  concave,  smaller 
than  the  dorsal,  and  bearing  a  deep  and  very  broad  triangulär  pedicle  notch, 
which  extends  from  just  behind  the  beak  to  the  posterior  margin.  Apex  of 
notch  occupied  by  a  triangulär  plate  or  listrium.  Surface  marked  by 
concentric  growth  lines ;  no  muscular  impressions  visible  on  the  interior. 
Dorsal  valve  more  or  less  convex,  with  beak  marginal.  External  surface 
radially  striated.  On  the  interior,  a  low  median  ridge  extends  from  the  apex 
to  beyond  the  centre  of  the  valve ;  posterior  adductor  muscles  strong ;  the 
anterior  ones  faint.     Ordovician  to  Devonian ;  North  America. 

Lingulodiscina  Whitfield  (Oehlertella  Hall  and  Clarke).  Much  like  Schizo- 
crania^ but  the  ventral  valve  has  concentric  growth  lines,  and  no  radiating 
Striae.  Ventral  pedicle  area  greatly  elevated  and  transected  by  a  narrow 
open  fissure.     Devonian  to  Lower  Carboniferous  ;  North  America. 

Schizobolus  Ulrich.  Devonian;  North  America.  (?)  Monoholina  Salter. 
May  be  an  Obolid. 

Family  2.     Discinidae  Gray. 

Derived  Discinacea  with  an  open  pedicle  notch,  in  early  life,  in  the  posterior 
margin  of  the  ventral  valve,  which  is  closed  posteriorly  during  neanic  growth,  leaving 
a  more  or  less  long,  narrow  slit,  partially  closed  by  the  listrium.  Ordovician  to 
Recent. 

Orbiculoidea  d'Orbigny  (Fig.  556).  Shells  inequivalved,  sub-circular  or 
sub-elliptical  in  outline.     Apices  eccentric.      Ventral  valve  deperssed,  convex 


378 


MOLLUSCOIDEA 


PHYLUM  V 


Fig.  556. 

A,  OrUculoidca  circe  Bill.  Ordovician;  Belle' 
ville,  Canada.  Ventral  valve,  Vi  (after  Billings). 
B,  0.  nitida  Phill      "  - 

souri 


or  flattened.     Dorsal  valve  larger,  usually  depressed  conical.     Pedicle  furrow 
B  originating    behind    the    apex,    extending 

over  a  greater  or  lesser  portion  of  the 
radius  of  the  valve,  and  prodiiced  at  the 
distal  end  into  a  short  tubulär  sipho,  emerg- 
ing  on  the  interior  surface  near  the  posterior 
margiii.  Surface  with  fine,  crowded  or  dis- 
tant,  rarely  lamellose,  concentric  lines, 
occasionally  crossed  by  radiating  lines. 
Ordovician  to  Cretaceous;  North  and  South 
America,  Europe,  and  probably  elsewhere. 
Discina  Lamarck.  Very  much  like 
Do™-'  2/,^vertra?vXM/r' '  ^'''   Ofbiculoidea,  but  the  pedicle  emerges  through 

the  ventral  valve  antero-posteriorly,  im- 
mediately  beneath  the  beak,  instead  of  through  a  sipho  postero-anteriorly  as 
in  that  genus.     Recent. 

Until  recently  Discina  embraced  all  fossil  Discinoid  shells,  but  at  present 
this  genus  seems  to  be  restricted  to  a  single  species, 
D.  striata,  living  off  Cape  Palmas,  West  Africa. 

Discinisca  Dali  (Fig.  557).  Like  Orbiculoidea, 
but  with  a  small  septum,  as  in  Discina,  behind 
which  is  an  impressed  area,  externally  concave  and 
internally  elevated.  This  is  perforated  by  a  longi- 
tudinal  fissure,  extending  from  a  short  distance 
behind  the  septum  nearly  to  the  posterior  margin.  ^.^l^;,^^ 
Tertiary  to  Recent ;  North  America  and  Europe. 

Pelagodiscus  Dali.     Like   Discinisca,  but   the  brachia  are  without  spirals 
Recent ;  deep  oceans. 

Schizotreta  Kutorga.     Ordovician  and  Silurian  ;  Russia  and  North  America 
Lindstroemella  and  Boemerella  Hall  and  Clarke,  are  genera  related  to  Orhi 
culoidea.     Devonian  ;  North  America. 


Fig.  557. 

Discinisca  lamellosa  (Brod.).  Recent ; 
A,  Side-view.  B,  Interior  of 
valve.     C,  Exterior  of  same. 


Superfamily  4.     CRANIACEA  Waagen. 

Specialised,  cemented  calcareous  Neotremata  without  pedicle  or  anal  openings  at 
maturity.  Pedicle  functional  probably  only  during  nepionic  growtli.  Ordovician 
to  Recent. 


Family  1.     Oraniidae  King. 

Crania  Retzius.  Shell  inequivalve,  sub-circular  in  outline.  The  interior 
of  both  valves  shows  two  pairs  of  large  adductor  scars,  the  posterior 
of  vi^hich  are  widely  separated  and  often  strongly  elevated  on  a  central 
callosity.  Impressions  of  the  pallial  genital  canals  coarsely  digitate.  Ordo- 
vician to  Recent ;  maximum  development  in  Ordovician  and  Cretaceous. 

Pseudometoptoma  von  Huene.  Very  large  thick-shelled  forms  with  high 
dorsal  valves.     Ordovician  ;  Esthonia. 

Philhedra  Koken.     Ordovician  ;  Europe  and  America. 

Petrocrania  Raymond  (Craniella  Gi^hlert  1888,  no?i  Schmidt  1870).  Large 
Craniids  with  S-shaped  vascular  impressions.  (?)  Ordovician  and  Devonian  ; 
North  America  and  Europe. 


CLASS  II 


BRACHIOPODA 


379 


Eleutlierocrania   von    Huene.     Biconvex  Craniids    related    to   Petrocrania. 
Ordovician ;  Esthonia. 

A  B  V 


Fig.  558. 

Craniscus  velatus  (Quenst. ). 
Upper  Jura;  Oerlinger 
Thal,  Würteniberg.  Interior 
of  ventral  valve,  Vi  (after 
Quenstedt). 


Fig.  559. 

Ancistr<}crania  parisiensis  (Defr.).  Upper  Cretaceous ;  France. 
A,  Prottle  of  dorsal  valve.  B,  Interior  of  same.  C,  Interior  of  ven- 
tral valve,  i/j. 


Craniscus  Dali  (Fig.  558).     Ventral  interior  divided  by  septa  into  three 
cavities.     Jurassic ;  Europe. 

Ancistrocrania  Dali  (Fig.   559).     Dorsal  valve  with  two  muscular  fulcra. 


Fig.  560. 

Isocrania  igfiabergensis  (Retzius).    Uppermost  Cretaceous  ;  Ignaberga,  Scania.     A,  Profile  and  dorsal  aspect 
of  Shell,  i/j.     B,  C,  Interior  of  ventral  valve.     D,  Interior  of  dorsal  valve,  enlarged. 

Cretaceous ;  Europe.  Isocrania  Jaekel  (Fig.  560).  Exterior  plicate. 
Cretaceous ;  Europe. 

Fholidops  Hall  (Craniops  Hall).  Biconvex  and  but  slightly  attached 
Craniids.     Ordovician  to  Carboniferous  ;  North  America,  England,  Gotland. 

Fseudocrania  M'Coy  (Palaeocrania  Quenstedt).  Radially  striated  shells 
much  lik'e  Fholidops.     Ordovician  ;  Europe. 

Cardinocrania  Waagen.     Permian  of  India. 

Order  3.     PROTRBMATA    Beecher. 

Specialised  (through  atrematous  Kutorginacea),  articulate,  calcareous 
Brachiopoda,  with  well-developed  cardinal  areas.  Exterior  surface  nearly 
always  either  plicate,  striate  or  spinous,  and  but  rarely  smooth.  Pedicle 
aperture  restricted  to  the  ventral  valve  throughout  life  and  more  or  less 
closed  by  a  deltidium  ;  in  some  forms  the  pedicle  is  functional  only  in  early 
life  and  later  the  animals  cement  the  ventral  valve  to  foreign  bodies.  Chilidium, 
spondylium  and  cruralium  often  present.  Brachia  unsupported  by  a  calcareous 
skeleton  other  than  short  crura. 


Superfamily  1.     ORTHACEA  Walcott  and  Schuchert. 

Progressive  Frotreinata.  The  older  gener a  have  immature  spondylia  that  are 
rarely  freely  suspended  but  are  conimonly  cemented  directly  to  the  valves  (  =  pseudo- 
spondylia).     In  the  great  majority  of  the  later  gener a  all  traces  of  spondylia  are  lost. 


380  MOLLUSCOIDEA  phylum  v 

In  earlyforms  thepedide  aperture  is  usually  covered  hy  deltidia  and  chilidia,  but  in  most 
later  fonns  these  plates  are  lost.  Fedicle  always  fundional  and  in  the  great  majority 
of  forms  emerges  freely  out  of  the  delthyrium.  Cardinal  process  more  or  less  well 
developed  except  in  the  most  primitive  genera.  Ä  prolific  stock  of  Brachiopods. 
Throughout  Paleozoic. 

Family  1.     Billingsellidae  Scliucliert. 

Primitive  Orthacea  with  a  more  or  less  dosed,  or  an  open  delthyrium.  A 
Cardinal  process  arises  in  this  family  and  is  therefore  either  absent,  rudimentary  or 
well  developed.  Ä  spondylium  is  usually  developed  and  to  its  upper  surface  are 
attached  the  muscles  of  the  ventral  valve.  Cruralia  rudimentary.  Shell  strudure 
dense,  granulär,  lamellar,  rarely  fibrous,  apparently  irregularly  pundate  in  some 
forms.     Cambrian. 

Siibfamily  A.     Nisusiinae  Walcott  and  Scliiichert. 

Primitive  Billingsellidae  with  more  or  less  well -developed  deltidia  and  with  or 
without  rudimentary  chilidia.  Spondylia  and  cruralia  rudimentary  or  small,  not 
supported  by  septa.     Cardinal  process  generally  absent,  but  rudimentary  when  present. 

Nisusia  Walcott,  and  subgenus  Jamesella  Walcott.  Distinctly  plicate 
Billingsellidae  without  cardinal  process.  Deltidium  well  developed  with  an 
apical  pedicle  foramen.  The  genus  has  a  spiniferous  exterior  while  the  sub- 
genus is  devoid  of  spines.  Lower  and  Middle  Cambrian  of  America  and 
Europe. 

Protorthis  Hall  and  Clarke.  Has  a  spondylium,  but  the  deltidium  is  widely 
open  for  the  protrusion  of  the  pedicle.  Shell  substance  apparently  punctate. 
Middle  and  Upper  Cambrian  of  America  and  Sweden.  The  subgenus  Loperia 
Walcott,  difFers  in  having  the  ventral  umbo  high  and  convex  while  the  rest 
of  the  Shell  is  concave.     Middle  Cambrian ;  Cape  Breton,  Nova  Scotia. 

Subfamily  B.     Billingsellinae  Walcott  and  Schucliert. 

Primitive  Billingsellidae  very  much  like  the  Nisusiinae,  but  without  true  spondylia 
(i.e.  pseudospondylia  are  often  present)  and  cruralia.     There  is  a  more  or  less  well- 
simple cardinal  process  except  in  Lower  Cambrian  forms. 

Billingsella  Hall  and  Clarke  (Fig.  561).     Shells  essentially  orthoid,  plicate, 

biconvex  or  planoconvex,  and  prob- 
ably  punctate.  Deltidia  well  de- 
veloped, but  chilidia  only  partially 
so;  the  pedicle  may  emerge  be- 
tween  these  plates  or  pass  apically 
through  the  deltidium.  Common 
and  widely  distributed  throughout 
the  Cambrian  of  America,  Europe 

Billingsella  coloradoensis  (Shumard).     Middle  Cambrian ;  i  pti  •  ,  i                          i  •               ,     • 

Texas.    A,  Ventral  exterior.    B,  Ventral  interior.    C,  Dorsal  ^-UQ  Uniua  ;  tnc   gCnUS    Qies    OUt    in 

interior.     c,  Crural  bases ;  d,  Deltidium;  j,  Cardinal  pro-  fV,p  T.n-«7-pr  OrrlnviVinn         TVip    emh- 

cess ;«,  Teeth  ;  vs,  Vascular  sinuses  (after  Walcott).  tne  l^OWer  UrüOVlCian.        lue    SUD 

genus  Otusia  Walcott,  has  small 
eared  forms  without  deltidia  and  with  a  well- developed  cardinal  process. 
Upper  Cambrian  ;  North  America. 


Fin.  561. 


CLASS  II 


BRACHIOPODA 


381 


Wimanella  AValcott.  Like  Billingsella  but  more  primitive  in  that  the 
exterior  is  smooth.  Lower  Cambrian ;  North  America.  Wynnia  Walcott. 
Middle  Cambrian ;  India. 

Siibfamily  C.     Eoorthinae  Walcott. 

Derived  Billingsellidae  in  which  the  delthyria  are  nearly  always  vndely  open  as 
in  Orthids ;  deltidia  and  chilidia  sometimes  retained  throughout  life,  hut  more  often 
only  in  the  younger  growth  stages.  Spondylia  ahsent.  Cardinal  process  well 
developed.  Differ  from  the  Orthidae  mainly  in  that  the  shell  structure  is  dense, 
granulär,  and  with  irregularly  pundate  lamellae. 

Eoorthis  Walcott.  Very  much  like  Pledorthis,  but  the  shell  is  thinner 
and  its  structure  not  fibrous.  Middle  Cambrian  and  Lower  Ordovician,  but 
essentially  of  Upper  Cambrian  time ;  North  America,  China,  Argentina  and 
north  Europe.  .  Subgenus  Orusia  Walcott,  typified  by  Orthis  lenticularis 
Wahlenberg.  Upper  Cambrian  of  north-western  Europe  and  New  Brunswick. 
Subgenus  Fhikelnhurgia  Walcott,  has  thick  shells  with  strongly-marked  ventral 
vascular  trunks.     Upper  Cambrian  ;  North  America. 

Family  2.     Orthidae  Wood  ward. 

Progressive,  divergent  and  terminal  Orthacea,  derived  out  of  the  Eoorthinae, 
nearly  always  with  large  open  delthyria.  Cardinal  process  well  developed.  Shell 
structure  fibrous,  impunctate  or  punctate.  Ventral  muscle  area  small,  obovate  or 
obcordate  ;  adductors  extending  to  anterior  margin  of  area.    Ordovician  to  Permian. 


Subfamily  A.     Orthinae  Waagen  (emend,). 
Orthidae  with  the  shell  impunctate. 

Orthis  Dalman  (s.  str.)  (Orthambonites  Pander).  Typified  by  0.  callactis 
Dalman,  or  0.  tricenaria  Conrad.  Shells  plano-convex ;  costae  strong,  few, 
generally  sharp  and  but  rarely  bifurcating.  Cardinal  process  a  thin  vertical 
plate.  There  may  be  a  flat  apical  deltidium.  Plications  often  with  large 
oblique  tubules  penetrating  the  external  layers.  Ordovician  and  Silurian ; 
Europe,  North  America,  etc. 

Plectorthis  Hall  and  Clarke.  Valves  subequally  convex.  Ventral  cardinal 
area  low.  Plications  strong,  simple  or  duplicate.  Ordovician  and  Silurian ; 
North  America  and  Europe.  a  b 

The  following  are  Ordo- 
vician subgenera  :  Austin- 
ella, Eridorthis,  and  Encu- 
clodema  Foerste  (Cyclocoelia 
Foerste,  non  Duj.). 

Platystrophia  King  (Fig. 
562).  Contour  spiriferoid ; 
hinge-line  long  with  dorsal 
and  ventral  cardinal  areas 
equally  developed.  Strong,  sharp  plications  with  the  exterior  surface  finely 
granulöse.     Ordovician  and  Silurian  ;  Europe  and  America. 

Hebertella  Hall  and   Clarke.     Shells  with   convexity  of   valves   reversed. 


Platystrophia  lynx  (Eichw.). 


Fio.  562. 
Ordovician  ;  Cinciunati,  Ohio.    i/i. 


382  MOLLUSGOIDEA  phylum  v 

Exterior  finely  plicate,  crossed  by  lamellose  growth  lines.  Ventral  muscular 
area  short,  obcordate.  Cardinal  process  well  developed,  often  crenulate. 
Ordovician ;  America  and  Europe. 

Orthostrophia  Hall.  Exterior  like  Hehertella.  Muscular  area  of  both 
valves  short,  deeply  excavate,  with  the  vascular  and  ovarian  markings 
conspicuous.      Silurian   and    Lower    Devonian ;  North   America.      Subgenus  : 

Schizoramma  Foerste  (Schizonema  Foerste,  non  Agardh.). 

Silurian ;  North  America. 


Subfamily  B.     Dalmanelltnae,  novum. 
Orthidae  with  the  shell  ahundantly  pundate. 
^^•'•^^^-  Dalmanella  Hall  and  Clarke  (Fig.   563).     Widely 

Silurian ;  Gotiand.   i/i-        distributed  in  the  ürdovician  and  öilurian,  but  persist- 

ing  to  the  end  of  the  Devonian. 
Thiemella  Williams.     Upper  Devonian  ;  North  America. 

Family  3.     RhipidomelÜdae,  novum. 

Progressive,  divergent  and  terminal  Orihacea  with  the  external  charaders  of  the 
Orthidae,  Shell  strudure  fibrous,  impundate  or  pundate.  Ventral  muscular  area 
large,  hilohed  or  elliptical ;  addudors  relatively  small,  and  more  or  less  completely 
enclosed  anteriorly  by  the  flabellafe  didudors.     Ordovician  to  Upper  Carbonif erous. 

Subfamily  A.     Plaesiomiinae,  novum. 
Rhipidomellidae  with  the  shell  ii 


Plaesiomys  Hall  and  Clarke.  Relative  convexity  of  valves  reversed. 
Surface  finely  plicate  and  sometimes  tubulose.  Cardinal  process  thickened 
and  crenulate.  Ventral  muscular  scars  large  and  often  bilobed.  Ordovician  ; 
America  and  Europe.  Subgenus  :  Dinorthis  Hall  and  Clarke.  Surface  strongly 
plicate ;  there  may  be  a  small  deltidium.  Ordovician ;  North  America. 
Subgenus :  Valcourea  Raymond.  Near  Plaesiomys  but  strophomenoid  in  external 
expression.     Lower  Ordovician ;  North  America. 

Pionodema  Foerste  (Bathycoelia  Foerste,  non  Am.  Serv.).  Biconvex  Orthids, 
finely  striate,  some  of  them  tubulose.  Resemble  small  Schizophoria  but  are 
impunctate.     Lower  Ordovician  ;  North  America. 

Subfamily  B.     Khipidomellinae,  novum. 
Rhipidomellidae  with  the  shell  abundantly  pundate  and  finely  striate. 

Heterorthis  Hall  and  Clarke.  Contour  strophomenoid  with  the  ventral 
diductor  scars  very  large.     Ordovician ;  North  America         ^^  ^ 

and  Europe. 

Rhipidomella  QEhlert  (Rhipidomys  QEhlert,  non 
Wagner).  Biconvex,  sub-circular  shells  with  short 
hinge-lines.  Striae  generally  hollow  and  open  on  the 
surface  into  (1)  short  tubulär  spines.      Late  Ordovician  p^,,  r,Q^^ 

into  Pennsvlvanian  ;  widely  distributed  throughout  the     BiiohUesbaobus(jjum.).  siiu- 

,,  -^  ^  ./  o  ^j^^.    Qotiand.     A,   Shell,   i/i- 

World.  B,  Interior  of  dorsal  valve,  -^/j. 


CLASS  II 


BRACHIOPODA 


383 


BiloUtes  Linn.  (Dicoelosia  King)  (Fig.  564).  Silurian  and  Lower  Devonian  ; 
Europe  and  North  America. 

Schizophoria  King  (Fig.  565).  Relative  convexity  of  valves  reversed. 
Large,  very  finely  striate,  with   the  Striae    hollow  and   spinöse!      Cardinal 


Fk;.  565. 
A-C,  Schizophoria  striatula  (Schloth.)-      Devonian  ;   Gerolstein,  Eifel.     A,  Dorsal  aspect.     B,  Interior  of 
dorsal  valve.      C,  Interior  of  ventral  valve.      D,  S.  vulvaria  (Schloth.).      Spiriferensandstein  (Lata  Lower 
Devonian) ;    Niederlahnstein,  Nassau.     Internal  mould.     (All  tigures  of  the  natural  size.) 

process  in  mature  shells  with  accessory  ridges  making  it  multilobate.  Dorsal 
interior  marked  by  4  to  6  deep  pallial  sinuses.  Silurian  to  Goal  Measures ; 
widely  distributed  throughovit  the  world.  Subgenus :  Orthotichia  Hall  and 
Clarke.  Like  Schizophoria  externally,  but  in  the  ventral  valve  the  dental 
lamellae  and  a  median  septum  are  highly  developed.  Goal  Measures ;  Brazil 
and  India. 

Subfamily  C.     Enteletinae   Waagen. 

Rhipidomellidae  with  decidedly  convex  valves  and  a  few  hroad  plications  super- 
added  to  the  very  fine  radial  Striae.     Developed  out  of  Orthotichia. 

Enteletes  Fischer  {Syntrielasma  Meek  and  Worthen).  Dorsal  valve  more 
convex  than  ventral.  Hinge-line  short  with  a  high  ventral  cardinal  area.  In 
the  ventral  valve  the  dental  lamellae  are  high  and  convergent,  and  between 
them  is  a  marked  median  septum  ;  the  crural  septa  of  the  dorsal  valve  are 
also  well  developed.  Goal  Measures  and  Permian  ;  North  and  South  America, 
Europe  and  Asia. 

Enteletoides  Stuckenberg.     Upper  Garboniferous  ;  Russia. 


Superfamily   2.    STROPHOMENACEA   Schuchert. 

Progressive,  terminal  Protremata,  derived  out  of  Orthacea  (Billingsellidae),  with- 
out  spondylia  and  cruralia.  Deltidia  and  chilidia  nearly  always  present  throughout 
life  ;  cardinal  process  always  well  developed.  Pedicle  nearly  always  small,  emerging 
through  the  apex  of  the  valve,  or  lost  when  the  shells  cement  toforeign  objects  or  anchoi' 
by  means  of  ventral  spines.    A  prolific  stock  of  Brachiopods.    Ordovician  to  Recent. 

Family  1.     Strophomenidae  King. 

Primitive  Strophomenacea  with  well -developed  deltidia  and  chilidia.  Shells 
usually  ßat  or  concavo-convex  and  but  rarely  biconDex.  Pedicle  usually  functional 
but  tending  to  be  thin  and  weak,  and  often  lost  when  the  shells  cement  to  foreign 
objects  or  are  otherwise  held  to  the  substratum  {usually  by  spines).  Ordovician  to 
Permian. 


384 


MOLLUSCOIDEA 


PHYLUM  V 


Subfamily  A.     Eafinesquininae  Sclmchert. 

Strophomenids  that  as  a  rule  throughout  life  have  the  ventral  valve  convex  and 
the  dorsal  cbncave.  The  relative  form  of  the  valves  is  the  reverse  of  that  in  the 
Orthotetinae. 

Eostrophomena  Walcott.  Primitive,  small  forms  with  the  cardinal  process 
Alling  most  of  the  dorsal  delthyrium.  Teeth  inconspicuous,  with  the  muscular 
scars  almost  absent.  Surface  finely  striate  with  alternating  bundles  of  fine 
lines  between  single  coarser  ones.  Basal  Ordovician  ;  Sweden  and  North 
America. 

Primitive  Pledamlonites.  Upper  Cambrian 
and  Lower  Ordovician ;  North  America 
and  England. 

Plectella  Lamansky.  Intermediate 
between  Leptella  and  Plectambonites. 
Ordovician ;  Esthonia. 

(?)  Lamanshja  Moberg  and  Seger- 
berg.    Ordovician ;  Sweden. 

Pledamhonites      Pander       (Leptaena 

Davidson  and  auct.)  (Fig.  566).     Ordo- 

^,.,    .        vician    and    Silurian :    North    America 


Leptella  Hall  and  Clarke. 


Fig.  566. 


Plectambonites    transversalis   (Dalm.).      ^jinman ,  ,   -y-, 

Gotland.    ^,  Dorsal  aspect,  i/i-    -B,  Interior  of  dorsal    and  Europe. 

Svar'icfeors'' """''''  ""'""'  '^'   ^'  ''^''"'''" '  ""'  Leptaena  Dalman  (Leptagonia  M'Coy) 

(Fig.  567).  Shells  having  the  characters 
of  Bafinesquina,  but  the  flatter  portions  of  the  valves  with  corrugations  and 
wrinkles.  Where  these  cease, 
the  Shells  are  more  or  less 
abruptly  and  often  rect- 
angularly  deflected.  Ordovi- 
cian to  Lower  Carboniferous. 
Bafinesquina  Hall  and 
Clarke  (Fig.  568).  Shells 
normally  concavo  -  convex 
dorso-ventrally.  Striae  al- 
ternating in  size,  and  crossed 
by    finer    concentric    growth 

A 


Fig.  567. 

Leptaena  rliomboldalis  (Wahlenh.).    Silurian  ;  Gotland.     A,  B, 
Dorsal  aspect  and  profile.     C,  Interior  of  dorsal  valve. 


Fi(i.    568. 

A,  Bafinesquina  aüernata  (Conrad).     Ordovician;  Cincinnati,  Ohio,     i/l-     B,  E.  exxwmsa  (Sowerhy). 

Interior  of  ventral  valve,  showinc;  muscular  and  vascular  impressions. 


CLASS  II  BRACHIOPODA  385 

lines.  Muscular  area  of  ventral  valve  consisting  of  two  broad  flabellate 
diductor  scars  enclosing  an  elongate  adductor.  In  the  dorsal  valve,  the 
bilobed  cardinal  process  is  low  ;  the  posterior  arborescent  adductor  scars  well 
defined.  Vascular  and  ovarian  markings  often  well  indicated.  Ordovician 
and  basal  Silurian ;  North  America  and  Europe. 

Stropheodo7ita  Hall.  Shells  very  much  like  Eafinesquina,  but  with  the 
cardinal  margins  finely  denticulate  and  the  deltidium  flat  or  not  discernible. 
Silurian  and  Devonian  ;  North  America  and  Europe. 

Leptostrophia  Hall  and  Clarke  ;  Douvillina  CEhlert ;  and  Brachyprion  Shaler 
are  subgenera  of  Stropheodonta.     Silurian  and  Devonian. 

Pholidostrophia  Hall  and  Clarke.  Smooth  or  squamose,  nacreous  small 
Stropheodontas.     Devonian  ;  North  America  and  Europe. 

Strophonella  Hall  (Amphistrophia  Hall  and  Clarke).  Eesupinate  Stropheo- 
dontas.     Silurian  and  Devonian  ;  North  America  and  Europe. 

Gaspesia  Clarke.  Aberrant  Strophomenid  recalling  coarsely  plicate  Orthids. 
May,  however,  be  a  Pelecypod.     Lower  Devonian ;  Gaspe,  Canada. 

Subfamily  B.     Tropidoleptinae  Schuchert. 

Aberrant  Strophomenidae  with  two  very  long  slender  crura  that  unite  vnth  a  high 
vertical  dorsal  septum.  The  family  is  sometimes  regarded  as  better  placed  among  the 
Terebratellids  of  the  Terebratulacea. 

Tropidoleptus  Hall.  Plano-convex,  plicated  shells  with  a  long,  straight  and 
narrow  cardinal  area.  Teeth  and  dental  sockets  corrugated  on  their  outer 
surfaces.     Devonian  ;  America,  Europe  and  South  Africa. 


Subfamily  C.     Davidsoniinae  King. 

Small  specialised  Strophomenids,  derived  out  of  Eafinesquininae  and  devoid  of  a 
being  cemented  by  the  ventral  valve  to  foreign  objeds. 


Christiania  Hall  and  Clarke.  DifFers  from  Leptaenisca  in  having  prominent 
longitudinal  ridges  instead  of  spiral  markings  on  the  dorsal  interior.  Ordo- 
vician ;  North  America,  England  and  Eussia. 

Leptaenisca  Beecher.  Ventrally  cemented  shells  having 
some  of  the  characters  of  Plectambonites.  Markings  of 
the  fleshy  arms  are  retained  on  the  dorsal  shell.  Silurian 
and  Lower  Devonian  ;  North  America. 

Davidsonia  Bouchard  (Fig.  569).    Thick  Leptaenisca-Mke  ^^^  ^^^ 

Shells,  with  Spiral  markings  of  the  fleshy  arms  strongly       ^^^,,,,„,,;,   ,;^,,,,. 
impressed  on  both  valves.     Devonian;  England,  Belgium   iana d.-^ Kon.  Devonian ; 

^  .  cj  ^  Eifel.    Ventral  valve  witli 

and  KuSSia.  spiral  markings,  2/j. 

Subfamily  D.     Orthotetinae  Waagen. 

Strophomenids  with  the  ventral  valve  convex  during  early  growth,  becoming  sub- 
sequently  concave,  or  the  reverse  of  the  order  in  the  Eafinesquininae.  In  the  later 
forms  both  valves  tend  to  be  convex. 

(?)  Orthidium  Hall  and  Clarke.     Basal  Ordovician  ;  North  America. 
VOL.  I  2  c 


386 


MOLLUSCOIDEA 


PHYLUM  V 


Strophomena  Blainville.     Shells  like  Bafinesquina,  but  with  the  relative  con- 
vexity  of  valves  reversed,  and  the  ventral  muscular  area  sharply  limited  by 

an   elevated   margin.     Ordovician ;  America 
and  Europe. 

Schuchertella  Girty  (Fig.  570).  Much  like 
Strophomena.  Shell  piano -convex,  concavo- 
convex  or  biconvex.  Surface  covered  with 
radiating  Striae,  which  are  convoluted  by 
sharp  concentric  lines.  Cardinal  area  of 
ventral  valve  prominently  developed  and  not 
attached  by  cementation  ;  dorsal  area  narrow. 
Dental  plates  rudimentary.  Cardinal  process 
united  to  crural  plates,  the  whole  forming 
a  vertical  subcrescentic  process.  Muscular 
impressions  flabelliform.  Silurian  to  Upper 
Carboniferous ;  North  and  South  America, 
Europe  and  India. 
Like  Schuchertella,  but  with  the  muscular  areas 
Lower  Devonian  ;  North  America. 


Fig.  570. 

Schuchertella  umhraculum  (Schloth.). 
Devonian  ;  Gerolstein,  Eifel.     Natural  size. 


Hipparionyx  Vanuxem. 
much  larger  and  no  dorsal  cardinal  area. 

Schellwienella  Thomas  (Orthothetes  Waagen,  non  Orthotetes  Fischer)  (Fig.  571). 


Fig.  571. 

Schellwienella  crenistria  (Phill.).  Lower  Carboniferous;  Wexford.  A,  Muscular  portion  of  vential  valve. 
B,  Interior  of  dorsal  valve.  A,  A',  Adductors ;  R,  Diductors ;  j,  Cardinal  process;  d,  Uental  sockets  (after 
Davidson). 

Near  Schuchertella,  but  with  short  diverging  dental  plates  and  the  cardinal  area 
either  rudimentary  or  absent,     Lower  Carboniferous  ;  Europe. 

Kayserella  Hall  and  Clarke.  Small  Schuchertella-like  shells,  with  a  very 
high  dorsal  median  septum.     Devonian  ;  Germany. 

Orthotetes  Fischer.  Like  Schuchertella,  but  in  the  ventral  valve  there  is  a 
small  triangulär  umbonal  Chamber  formed  by  the  uniting  of  the  dental  plates, 
in  front  of  which  is  a  well-developed  median  septum.  Ventral  cardinal  area 
usually  attached  by  cementation.  Upper  Carboniferous  and  Permian ;  North 
and  South  America,  Europe,  India  and  Russia. 

Derlya  Waagen.  Like  Orthotetes,  but  without  the  umbonal  Chamber. 
Lower  and  Upper  Carboniferous;  North  and  South  America,  Europe  and 
India, 

Omionia  Caneva.  Related  to  Orthotetes  as  Geyerella  is  to  Meekella.  Permian  ; 
Italy. 


CLASs  II  BRACHIOPODA  387 

Scacchinella  Gemmellaro.  Near  to  Derbya,  but  with  excessively  high 
ventral  cardinal  areas.  Ventral  beak  cemented  ?  Shells  resemble  Michiho- 
fehia,  but  have  originated  in  some  Orthotetinae  and  not  in  the  Productinae. 
Permian  ;  Sicily  and  Austria. 

Aräitreta  Whitfield.  Imperfectly  known,  but  seemingly  a  member  of  the 
Orthotetinae.     Upper  Carboniferous  ;  Arctic  America. 

Streptorhynchus  King.  Very  much  like  Schuchertella.  Ventral  area  high, 
Short,  twisted  and  probably  cemented.  Carboniferous  and  Permian  ;  America, 
Europe  and  India. 

Meekella  White  and  St.  John.  Very  biconvex  shells,  with  the  teeth  of  the 
ventral  valve  supported  by  very  long  dental  plates  which  are  nearly  parallel 
and  reach  to  the  bottom  of  the  umbonal  cavity  ;  no  median  septum.  Surface 
of  valves  with  coarse  costae  and  fine,  radiating,  often  plumose  Striae.  Upper 
Carboniferous ;  North  America,  Eussia,  India  and  China.  Subgenus  :  Ortho- 
thetina  Schellwien.  Like  Meekella,  but  without  costae.  Late  Upper  Carboni- 
ferous and  Permian ;  Europe. 

Geyerella  Schellwien.  Near  to  Meekella,  but  with  very  high  ventral  areas ; 
very  long  dental  septa  converging  and  uniting  in  a  median  septum.  Ventral 
beak  cemented.     Upper  Carboniferous  and  Permian ;  Europe. 

Subfamily  E.     Tripleciinae,  novum. 
Biconvex  Strophomenids  with  markedfold  and  sinus. 

Triplecia  Hall  (Dicraniscus  Hall).  Trilobate,  unequally  biconvex,  short- 
hinged  shells.  Cardinal  process  long,  erect  and  bifurcate.  Surface  smooth. 
Ordovician  and  Silurian ;  North  America,  England  and  Bohemia. 

Cliftonia  Foerste.  Striated  Triplecia.  Ordovician  and  Silurian  of  America 
and  Europe. 

Mimidus  Barrande.  Like  Triplecia,  but  with  the  median  fold  on  the 
ventral  valve.  No  external  evidence  of  a  deltidium.  Silurian  ;  Bohemia  and 
North  America. 

Streptis  Davidson.  Like  Triplecia,  but  biconvex  and  bilaterally  unsym- 
metrical.  Exterior  with  lamellar  concentric  shell  expansions.  Silurian; 
Europe  and  North  America. 

Family  2.     Thecidiidae  Gray. 

Cemented  StropKomenacea,  in  which  the  interior  of  the  shell  is  impressed  with 
variously  indented  brachial  furrows.     Carboniferous  to  Eecent. 

This  family  was  formerly  associated  with  the  Terebratulidae.  Beecher  has  shown, 
however,  that  brachial  Supports  are  wanting,  and  that  a  true  deltidium  is  present. 

Subfamily  A.     Leptodinae,  novum. 
Thecidiidae  with  the  brachial  markings  common  to  both  valves. 

Keyserlingina  Tscherny.  An  early  form  of  Leptodus,  with  few  brachial 
ridges.     Upper  Carboniferous  ;  European  Russia  and  Austria. 

Leptodus  Kayser  {Lyttonia  Waagen ;  Waagenopora  Noetling).  Very  large, 
highly  inequivalved,  irregulär  shells,  frequently  with  broad  lateral  expansions. 


388 


MOLLUSCOIDEA 


PHYIÜM  Y 


Numerous,  laterally  directed,  brachial  ridges  in  the  ventral  valve,  with  corre- 

sponding  divergent  grooves  in 
the  median  region  of  the  dorsal 
valve.    Permian;  China  and  India. 

Oldhamia  Waagen  (Fig.  572). 
Differs  from  Lejotodus  in  that  the 
ventral  valve  is  sub-hemispherical 
with  the  incurved  apex  covered 
by  a  callosity,  as  in  Bellerophon. 
Permian ;  India  and  China. 

Loczyella  Frech.     Said  to  be 

like    Leptodus,    but    without    the 

^, ,.     .    ,  .  .      r^    ^^"^  t  .    .     ^.  r.      brachial  rideres.     May  not  be   a 

Oldhamm  decipiens  Waagen.     Productus  Limestone ;  Salt    t,        ^  •  i  tt  /~i      ^ 

Range,  East  India.     A,  B,   Interior  of  ventral  and  dorsal    brachlOpod.  Upper        UarDOni- 

ferous  ;  Nanking,  China. 


valves,  respectively  (after  Waagen). 


Subfamily  B.     Thecidiinae  Dali. 
Thecidiidae  with  the  brachial  markings  restricted  to  the  dorsal  valves. 

Thecidea  Defrance  (Thecidium  Sowerby)  (Fig.  573).  Dorsal  brachial  im- 
pressions  with  three  pairs  of  symmetrical  lobes,  radially  directed.     Cretaceous. 

Thecidea  and  the  following  genera  of  the  subfamily  Thecidiinae  comprise  for  the 
most  part  small,  sometimes  extremely  minute  forms,  represented  from  the  Trias  to 
the  present  day ;  the  climax  of  diversity  occurred  in  the  Cretaceous. 

Lacazella  Munier-Chalmas  (Figs.  574,  575).     Dorsal  brachial  impressions 


Fig.  573. 

Thecidea  papillata  Schloth.  Upper 
Cretaceous  ;  Ciply,  Belgium.  A,  B,  In- 
terior of  ventral  and  dorsal  valves,  re- 
spectively, 2/j  (after  Woodward). 


Fig.  574. 

Lacazella  vertnicularis 
(Schloth.).  Upper  Cretaceous ; 
Maestricht.  Dorsal  valve,  2/j 
(after  Suess). 


Fig.  575. 

Lacazella  tnediter- 
ranea  (Risso).  Re- 
cent.  Interior  of 
dorsal  valve  showing 
brachia,  ^/i  (after 
Woodwaid). 


The  two  large,  dorsal,  brachial 


with   two   or  three  unequal  pairs  of  lobes,  medially   directed.     Jurassic  to 
Eecent;  Europe. 

Thecidiopsis  Munier-Chalmas  (Fig.  576). 
impressions  each  have  four  pairs  of  lobes 
laterally  and  medially  directed.     Creta- 
ceous ;  Europe. 

Thecidella  Munier-Chalmas.  Dorsal 
brachial  impressions  simple,  anteriorly 
directed.     Jurassic ;  Europe. 

Eudesella    Munier-Chalmas.      Trans- 
verse Shells  in  which  the  dorsal  brachial 
impressions  have  three  pairs  of  simple  lobes  antero-laterally  directed.  Jurassic; 
Europe. 


Fig.  576. 
Thecidiopsis  digitata(ßo\äii.).  Greensand  ;  Essen 
on  the  Rhine.    A,  Dorsal  aspect.    B,  C,  Interior 
of  ventral  and  dorsal  valves,  respectively,  l/j. 


CLASS  II 


BRACHIOPODA 


389 


Fterophloios  Gümbel  (Badrynium  Emmrich)   (Fig.   577).     Dorsal  brachial 
impressions  with  about  ten  laterally  directed  lobations.     Alpine  Rhaetic. 

Davidsonella  Munier-Chalmas.  Elongate  shells  with 
the  long,  narrow,  dorsal,  brachial  impressions  simple 
and  antero-laterally  directed.     Jurassic  ;  Europe. 

(?)  Cadomella  Munier-Chalmas.     Lias  ;  Europe. 


Family  3.     Productidae  Gray. 

Strophomenacea   with   hollow   anclioring   spines. 
Ordovician  to  Permian. 


Late 


Fio.  577. 

Pterophloios  emmrichi  Güm- 
bel. Ehaetic ;  Kössen,  Tyrol. 
Interior  of  dorsal  valve,  i/i. 


Subfamily  A.     Chonetinae  Waagen. 

Froductids  with  the  few  anchoring  spines  restrided  to  the  ventral  cardinal  margin. 

Chonetes  Fischer  (Fig.  578).  Shell  transversely  elongate,  semicircular  in 
outline,  typically  concavo-convex,  sometimes  plano-convex.  Upper  margin  of 
cardinal  area  in  ventral  valve  bearing  a  single  row  of  hollow  spines ;  these  are 
prolongations  of  tubes  which  penetrate  obliquely  the  substance  of  the  shell 
along  the  hinge-line.  Teeth  strong.  Cardinal  process  of  dorsal  valve  divided 
by  a  narrow  median  and  two  broader  lateral  grooves.  Brachial  impressions 
more  or  less  distinct.  External  surface  usually  covered  with  radiating  Striae, 
rarely  smooth  or  concentrically  rugose,  Late  Ordovician  to  Permian.  Sub- 
genus  :  Eodevonaria  Breger.  Chonetids  with  denticulate  hinge-lines.  Lower 
Devonian  ;  America  and  Europe. 

Anoplia  Hall  and  Clarke.  Smooth  or  squamose  shells  like  Chonetes,  sup- 
posed  to  be  without  cardinal  spines.     Lower  Devonian ;  North  America. 

Chonostrophia  Hall  and  Clarke.     Like  Chonetes,  but  with  the  shell  reversed 
Lower  and  Middle  Devonian  ;  North  and  South  America. 

Chonetella  Waagen.  Upper 
Carboniferous  ;  India.  Chonetina 
Krotow.     Permian ;  Russia. 

(?)  Daviesiella  Waagen.  Shell 
productoid,  but  without  spines 
and  well-developed  cardinal  area 
and  teeth.  Upper  Carboniferous ; 
England. 

(?)  Aulacorhynchus  Dittmar  {Iso- 
gramma  Meek  and  Worthen).  Very 
large,  transverse,  thin  shells  with  a 
ventral  platform.  Exterior  surface 
with  numerous,  regulär,  continuous, 
concentric  ridges.  Upper  Car- 
boniferous ;  Europe  and  North 
America. 


or  concavo-convex. 


Fin.  578. 

A,  Chonetes  striatelhis  (Dalm.).  Silurian  ;  Gotland.  i/i- 
B,  Interior  of  dorsal  valve  (after  Davidson).  C,  C.  sar- 
cinulatus  de  Kon.     Devonian  ;  Coblenz.    i/j. 


Subfamily  B.     Prodüctinae  Waagen. 

Produdids  with  the  anchoring  spines  more  or  less  ahundant  over  the  entire  ventral 
and  sometimes  also  over  the  dorsal  valve. 

Produdella  Hall.     Shells  small,  productoid,  with  narrow  cardinal  areas  in 


390 


MOLLUSCOIDEA 


PHYLUM  V 


both  valves.     Ventral  valve  with  small  teeth ;  dorsal  valve  with  sockets  and 

crural  plates.    Brachial  impressions  distinct.    Devonian  ;  America  and  Europe. 

Produäus  Sowerby  (Pyxis  Chemnitz ;  Arhusculifes  Murray  ;  Protonia  Linck ; 

Producta  Sow.)  (Figs.  579,  580).     Shell  without  functional  pedicle,  anchored 


Fig.  579. 

A,  Productus  semiretimlatus  (Martm).  Lower  Carboniferous ;  Vise,  Belgium.  Vi-  B,  P.igiganteus(M.a.rtm). 
Same  horizon  ;  England.  Interior  of  dorsal  valve  (after  Woodward).  C,  D,  P.  horridus  Sow.  Permian ;  Prussia 
and  England,  i/i-  C,  Interior  of  dorsal  valve.  D,  Internal  mould  of  ventral  valve.  A,  Adductors  ;  R,  Diductors  ; 
pr,  Cardinal  process ;  h,  Hinge-line  ;  v,  Brachial  impressions. 

by  the  ventral  spines ;  concavo-convex,  valves  usually  produced  anteriorly  ; 

outlines    semicircular,    sometimes    transversely    elongate.     External    surface 

spinöse,  usually  with  more  or  less  prominent  radiating 

ribs,  which  are  crossed  by  concentric  lines  or  wrinkles ; 

rarely  smooth  or  finely  striated.     Cardinal  areas,  teeth, 

sockets    and    crural    plates    absent    or    rudimentary. 

Ventral  valve    convex,   sometimes    geniculated;    often 

Fig.  580.  with  median  sinus.     Muscular  impressions  consisting  of 

Productus  horridus  sowerhy.  two  deudritic  adductors  and  a  pair  of  broadly  flabel- 

Permian ;  Gera,  Germany.  1/4-1  •  t -1  /-i       t       i  i 

late,  striate  diductors.  Cardinal  process  strong,  curved 
or  erect,  extending  far  above  the  hinge-line.  Brachial  ridges  well  defined  ; 
traces  of  spiral  or  brachial  cavities  occasionally  present  in  the  pallial  region. 
Extraordinarily  abundant  in  Carboniferous  and  Permian.  Distribution 
general. 

P.  giganteus  is  the  largest  Brachiopod  known,  sometimes  attaining  a  width  of  nearly 
one  foot. 

Subgenera :  Diaphragmus  Girty.  Productus  with  an  internal  plate  in  dorsal  valve. 
Upper  Carboniferous  ;  North  America.  Marginifera  Waagen.  Has  thickened  internal 
submarginal  ridges.     Upper  Carboniferous  ;  North  America,  India. 

Tschernyschewia  Stoyanow.  Typified  by  Productus  humholdti  d'Orb.  Upper 
Carboniferous;  India,  Russia. 


CLÄSS  II 


BRACHIOPODA 


391 


Proboscidella  (Ehlert.  Valves  very  unequal;  dorsal  valve  small,  concave, 
operculiform ;  ventral  valve  larger,  convex,  furnished  with  two  lateral  expan- 
sions  which  bend  downward  to  meet  the  margins  of  the  dorsal  valve,  and  an 
anterior  expansion,  which  is  produced  forward  into  one,  or  occasionally  two, 
long  cylindrical  tubes.     Carboniferous ;  Europe  and  North  America. 


Subfamily  C.     Strophalosiinae,  noviim. 
Produdids  anchored  to  foreign  objeds  hy  the  spines  or  hy  most  of  the  ventral  shell. 

Chonopedus  Hall  and  Clarke.  Chonetes-like  shells,  but  cemented  ventrally 
to  extraneous  objects.  External  surface  reticulated  by  a  double,  oblique 
series  of  concentric  lines  and  fine  radiating  Striae.  Lower  Carboniferous ; 
North  America. 

Strophalosia  King  (Orthothrix  Geinitz ;  Leptaenalosia  King)  (Fig.  581). 
Shell   productoid  in  general 


form,  cemented  by  the  ven- 
tral umbo.  Both  valves 
with  well-defined  area,  del- 
tidium  and  chilidium.  Ven- 
tral valve  with  two  pro- 
minent teeth  unsupported 
by  dental  plates.  Muscular 
impressions  small ;  brachial 
ridges  distinct.  Surface  of 
ventral  valve  covered  with 
spines ;    that   of    the   dorsal 


\ 


\ 


Fig.  581. 
Strophalosia  goldfussi  (Münst.).     Permian ;  Gera,  Germany.     A, 
Dorsal  aspect.     B,  Profile.     C,  Interior  of  dorsal  valve  with  brachial 
impressions.     Natural  size. 


Middle  Devonian  to  Permian ; 


valve  either  spinous,   lamellose  or   smooth. 

Europe,  India,  North  and  South  America. 

Aulosteges  Helmersen.     Much  like  Strophalosia,  but  not  cemented  by  the 

ventral  umbo ;  deltidium  covered  with  small  spinules  and  the  surface  of  both 

valves  thickly  set  with  spines.     Permian  ;  Russia  and  India. 

Etheridgina   (Ehlert.      Shell  very   small,   nearly  as    broad   as   long,   and 

attached  to  foreign  bodies,  notably  crinoid  stems,  by  the  spines  of  the  ventral 
valve.  Dorsal  valve  with  a  small  beak  ;  surface  ornamented 
by  concentric  flexuous  plications  bearing  a  few  scattered 
spines.     Carboniferous ;  Scotland. 


Family  4      Richthofeniidae  Waagen. 

Strophomenacea  developed  out  of  the  Produdidae,  and 
remarkably  modified  by  ventral  cementation.  The  form  is  that 
of  cyathophylloid  corals  with  an  operculiform  dorsal  valve. 
Shell  strudure  cystose.     Upper  Carboniferous  and  Permian. 

Tegulifera  Schellwien.  A  youthful  expression  of  the 
highly  modified  Eichthofenia,  in  which  the  productoid 
characters  are  still  recognisable.  Upper  Carboniferous; 
Au  Stria. 

Eichthofenia  Kayser  (Fig.  582).    These  most  remarkably 


Fio.  582. 

Richthofenia  lawrenci- 
a«a  Waagen.  Permo-Car- 
boniferons ;  Salt  Range. 
Vertical  section  of  ven- 
tral valve  (after  Waagen). 


392 


MOLLUSCOIDEA 


PHYLUM  V 


modified  Brachiopods  are  found  in  the  Permian  of  China,  India,  Sicily  and 
Texas. 

Gemmellaroia  Cossman  (Megarhynchus  Gem.,  non  Lap.).     Permian ;  Sicily. 


Superfamily  3.     PENTAMERACEA  Schuchert. 

Protremata  developed  out  of  Nisusiinae  among  the  Orthacea,  with  well- 
supported  or  free  spondytia,  and,  as  a  rule,  cruralia.  Deltidia  and  chilidia 
present  in  the  more  primitive  forms  and  generally  absent  in  the  last  developed  f amilies. 
The  least  prolific  stock  of  the  Protremata.     Cambrian  to  Permian. 


.     Family  1.     Syntrophiidae  Schuchert. 

Primitive  transverse  Pentaiaerids,  derived  out  of  Nisusiinae,  having  as  a  rule  long, 
straight  cardinal  areas  that  usually  are  devoid  of  deltidia  and  chilidia.  Spondylia 
and  cruralia  free  or  supported  by  septa.     Cambrian  and  Ordovician. 

(?)  Swantonia  Walcott  (Fig.  583).  Rostrate,  plicate,  small  and  rare  shells, 
with  a  free  but  small  spondylium.  Lower  Cam- 
brian :  North  America. 


ml 


Fig.  Ö83. 

Stvantonia  antiquata  (Bill.). 
Lower  Cambrian  ;  Vermont.  A, 
Ventral  exterior.  B,  Side  view 
of  same  showing  spondylium 
(after  Walcott). 


Fig.  584. 

SyntropMa  lateralis  (Whitfield).  Ordovician  ;  Fort  Cassin, 
Vermont.  A,  C,  D,  E,  Views  of  ventral  valve  showing  cardinal 
area  and  spondylium.  B,  Dorsal  valve.  F,  Cardinal  view  of 
both  valves  ground  away  to  sliow  section  of  spondylium  and 
cruralium  (after  Hall  and  Clarke). 


Syntrophia  Hall  and  Clarke  (Fig.  584).  Transverse,  straight-hinged, 
primitive  Pentamerids  with  open  delthyria  in  both  valves.  Spondylia  well 
developed  and  supported  by  an  incipient  septum  ;  cruralia  small  and  supported 
by  a  septum.  Middle  Cambrian  to  Lower  Ordovician ;  North  America. 
Subgenus :  Huenella  Walcott.  Has  a  plicate  surface.  Middle  and  Upper 
Cambrian ;  North  America,  China  and  Australia. 

Clarkella  Walcott.  Like  Syntrophia,  but  the  spondylium  is  supported  by 
three  septa.     Lower  Ordovician  ;  Montana. 


Family  2.     Olitambonitidae  Winchell  and  Schuchert. 

Divergent  transverse  Pentamerids,  derived  out  of  Syntrophiidae,  with  well- 
cardinal  areas,  deltidia,  chilidia  and  spondylia.     Cruralia  not  developed.     Essenti- 
ally  Ordovician  but  ränge  sparingly  into  Devonian. 

Clitambonites  Pander  (Orthisina  d'Orb. ;  Pronites  and  Gonambonites  Pander) 
(Fig.  585).     Valves  convex  or  sub-pyramidal.     Hinge-line  straight,  forming 


I 


CLASS  II 


BRACHIOPODA 


393 


the  greatest  diameter  of  the  shell.     Cardinal  area  of  the  ventral  valve  high ; 

delthyrium  broad,  and  covered  by  a  perforate  deltidium ;  that  of  the  dorsal 

valve  covered  by  a 

chilidium.       Dental 

lamellae  of  ventral 

valve  very  strongly 

developed,    uniting 

to  form   a   concave 

spatulate    plate    or 

spondylium.      This 

plate  serves  for  the 

attachment        of 

muscles,  and  is  sup- 

ported  by  a  median 

septum      extending 

for  about  one-half  the  length  of  the  valve.     External  surface  radially  striated 

and  often  lamellose.     Shell  substance  impunctate.     Ordovician  ;  North  Europe 

and  North  America. 

Subgenus  :   Hemi^nonites  Pander.     Biconvex  Orthid-like  forms  with  fine  non-lamellose 
Striae.     Ordovician  ;  Esthonia. 

Polytoechia  Hall  and  Clarke.  Like  Clitambonites  but  with  the  spondylia 
supported  by  three  septa,  thus  dividing  the  umbonal  cavity  of  the  ventral 
valve  into  five  Chambers.     Ordovician  ;  North  America. 

Scenidium  Hall  (Mystrophora  Kayser).  Small  orthisinoid  shells  with  the 
delthyrium  partially  closed  by  a  concave  imperforate  deltidium.  Cardinal 
process  extending  as  a  median  septum  throughout  the  length  of  the  shell. 
The  septum  is  sometimes  greatly  elevated  anteriorly  in  Devonian  species. 
Ordovician  to  Devonian  ;  North  America,  Europe  and  the  Urals. 


Fifi.  585. 

A,  Clitambonites  adscendens  (Fand.).  Ordovician  ;  Pawlowsk,  near  St.  Peters- 
burg, i/j.  B,  ü,  C.  squamatus  (Pahlen).  Ordovician ;  Kuckers,  Esthonia.  B, 
Interior  of  dorsal  valve,  showing  edge  of  the  chilidium.  C,  Interior  of  ventral 
valve,  showing  spondylium,  septum  and  deltidium  (after  Pahlen). 


Family  3.     Porambonitidae    Davidson. 

Derived  {out  of  Syntrophiidae),  progressive,  semi-rostrate  Pentamerids,  with  the 
deltidia  and  chilidia  vanishing  more  and  more  in  time.  Spondylia  and  cruralia 
present,  but  the  former  tends  to  thicken  and  unite  with  the  ventral  valve.  Ordovician 
to  Lower  Devonian. 


Subfamily  A.     Porambonitinae    Gill. 
Non-plicated  Porambonitidae,  with  the  shells  ezternally  pitted.    'Ordovician. 
Porambonites   Pander    (Isorhynchus  King)    (Fig.   586).     Shells    similar 

A  B  C  D  E  F 


to 


Fig.  380. 

Porambonites  aequirostris  (Schloth.).  Ordovician  (VaginatenRalk) ;  St.  Petersburg.  A-C,  Anterior,  lateral 
and  posterior  aspects  of  shell,  Vi.  D,  Punctate  surface,  magnified.  E,  F,  Interior  of  ventral  and  dorsal  valves, 
respectively. 

Parastrophia  in  form,   but  without  plications,  and  with   obtusely  triangulär 


394 


MOLLUSCOIDEA 


PHYLUM  V 


areas  in  both  valves.     Shells  thick,  variously  pitted  externally.     Ordovician ; 
Eussia. 

Noetlingia  Hall  and  Clarke.  Exterior  like  Porambonites,  but  with  long, 
straight  hinge-line,  prominent  cardinal  areas,  andperforate  beaks.  Ordovician; 
Russia. 

Subfamily  B.      Parastrophiinae,  novum. 

PUcated  Poramhonitidae.     Ordovician  to  Lower  Devonian. 

Camarella  Billings.  Small,  smooth  shells  with  a  few  low  plications  and 
without  cardinal  areas.  Dorsal  valve  at  maturity  most  convex.  Spondylium 
well  defined.  Cruralium  very  small,  supported  by  a  long  septum.  Ordovician  ; 
North  America  and  (?)  England. 

Parastrophia  Hall  and  Clarke.  Much  like  Camarella,  but  with  a  moderately 
long,  straight  cardinal  line,  and  no  cardinal  area.  Dorsal  umbo  conspicuous, 
projecting  beyond  that  of  the  ventral  valve.  Ordovician  and  Silurian  ;  North 
America  and  England. 

Änastrophia  Hall  {Brachymerus  Shaler,  non  Dej.).  Much  like  Parastrophia, 
but  with  the  dorsal  umbo  more  prominent  and  the  valves  with  numerous 
sharp  plications  extending  to  the  beaks.  Silurian  and  Lower  Devonian; 
North  America,  England  and  Gotland. 

(?)  Lycophoria  Lahusen.     Russia  and  Scandinavia. 


;  Family  4.     Pentameridae    M'Coy. 

Terminal,  usually  rostrate  Pentamerids,  developed  out  of  Poramhonitidae. 
Spondylia  and  cruralia  well  developed.  Sometimes  there  is  a  concave  plate  in  the 
ventral  delthyrium  that  is  interpreted  as  the  "deltidium  ;  if  so,  it  is  a  special  develop- 
ment  due  to  the  highly  incurved  beaks  of  both  valves  in  the  decidedly  convex  species. 
Silurian  to  Permian. 

Conchidium  Linn.  {Gypidia  Dalman ;  Antirhynchonella  Quenstedt ;  Zdimir 
Barrande)  (Figs.  587 ;  588,  D).     Shell  strongly  inequivalve,  biconvex,  with 


Fig.  587. 
Conchidium  Uloculare  Linn.     Silurian  ;  Gotland.     A,  Shell  of  the  natural  size.    B,  Beak  showing  concave 
deltidium.     C,  D,  Interior  of  dorsal  and  ventral  valves,  respectively.     x,  Spondylium ;  S,  Median  septum  of 
ventral  valve,  Fig.  D  ;  b,  Dental  lamellae  ;  c,  Crura  ;  S,  Septum-like  supports,  Fig.  Ü. 

n 

highly  arched  ventral  valve.  Surface  numerously  plicated.  Spondylium  narrow 
and  deep,  and  supported  by  a  high  vertical  septum  of  variable  length.  A 
small  cardinal  process  present.     Silurian  and  Devonian ;  distribution  general. 


CLASS  II 


BRACHIOPODA 


395 


Stricklandinia  Billings.  Similar  to  Conchidium,  but  with  a  straight  hinge- 
line  and  no  prominei*t  arched  ventral  beak.  Spondylium  small  and  short, 
supported  by  a  short  median  septum.  Silurian ;  North  America,  England 
and  Gotland. 

Pentamerus  Sowerby  (PentasÜre  Blainville).  Like  Conchidium,  but  with 
smooth  Shells,  or  sometimes  with  a  few  broad  and  obscure  radiating  undula- 
tions.     Silurian  ;  distribution  probably  general. 

Orthotropia  Hall  and  Clarke.  Similar  to  small  Pentamerus,  but  with  a 
short  hinge-line.     Differs  also  internally.     Silurian  ;  Wisconsin. 

Holorhynchus  Kiär.  Transverse  Pentamerus,  with  incipient  plications. 
Spondylium  not  supported  by  septum.     Silurian ;  Norway. 

Cajpellinia  Hall  and  Clarke.  Like  Pentamerus,  but  with  the  relative  con- 
vexity  of  the  valves  reversed.     Silurian  ;  North  America. 

Clorinda  Barrande  {Barrandella  Hall  and  Clarke).  Small  Gijpidula-\ikQ 
Pentamerids  usually  with  smooth  shells,  rarely  plicate.  Spondylium  with- 
out  a  supporting  septum.     Silurian  ;  North  America  and  Europe. 

Pentamerella  Hall.  Much  like  Clorinda,  but  with  strong  plications  and  a 
narrow  cardinal  area.     Devonian  ;  North  America. 

Sieberella  CEhlert ;  and  Gypidula  Hall.      (Fig.  588.)     Galeatiform  Penta- 


FiG.  588. 

Ä-Ct  Gypidula  galeata  (Dalm.).  Devonian  ;  Gerolstein,  Eifel.  A,  Dorsal  aspect,  i/i.  B,  Anterior  aspect. 
C,  Transverse  section  below  the  hinge-line.  (Lettering  the  same  as  in  Fig.  587,  C,  D.)  D,  Conchidium  knightii 
(Sow.).     Silurian ;  England.     1/2. 

merids,with  the  median  sinus  on  the  dorsal,  and  the  fold  on  the  ventral  valve. 
In  Sieberella  there  is  no  cardinal  area,  but  in  typical  Gypidula  there  is  a  well- 
defined,  cross-striated,  cardinal  area. 
Surface  smooth  or  plicate.  Silurian  and 
Devonian;  North  America  and  Europe. 

Branconia  Gagel.  Like  Gypidula, 
but  with  sharp  and  few  plications,  as 
in  Pugnax  of  the  Rhynchonellids.  Sil- 
urian ;  Glacial  drift  of  Germany. 

Seminula  M'Coy  {non  auct.).  Ac- 
cording  to  Buckman  the  genotype  is 
Terebratida  penta'edra  Phillips.  Shells 
rhynchonelliform  with  the  surface 
more  or  less  strongly  plicated.     Spon-  ^,^-7 1 iV^iil^^t  in^^^^^^^^^^ 

dvlium    SUDÜOrted    bv    a    long    median    of  shell,  enlarged.     pr,  Cardinal  process ;  c,  Crtira ; 
•^   ,  T^  •        i.     -n  •         T? .«     ^,  Spondylium;   g,   Dental   plates   of  dorsal  valve; 

septum.  Devonian  to  Permian ;  Europe,  ,,;  g'^  Median  septa. 

India  and  North  America.     Subgenus 

Camarophoria  King  (Fig.  589)  may,  according  to  Buckman,  be  used  for  the 

more  transverse,  fully  plicate  shells. 


Fig.  589. 


396  MOLLUSCOIDEA  phylüm  v 

■  Camarophorella  Hall  and  Clarke;       Biconvex,  sub-circular   Camarophoriae, 
biit  without  sinus,  f old  and  plications.     Lower  Carboniferous ;  North  America. 

Strophomenacea  of  unknown  relationships. 

Family  1.     Eichwaldiidae    Schucliert. 

Primitive  or  aberrant,  rostrate  Strophomenacea,  with  narrow  lateral  grooves  and 
ridges  for  articulation.  Delthyrium  closed  hy  a  concave  plate  {?  deltidium).  Pedicle 
emerging  through  the  ventral  umhone  and  moving  with  growth  anteriorly  hy  resorption 
through  the  shell,  as  in  Siphonotretidae.     Ordovician  and  Silurian. 

Eichwaldia  Billings.  The  single  species  of  this  genus  has  a  smooth 
exterior.     Ordovician  ;  North  America. 

Dictyonella  Hall  {Eichwaldia  auct.).  Exterior  surface  of  valves  pitted  in 
quincunx,  resembling  Trematis.  Silurian ;  North  America,  England,  Bohemia 
and  Gotland. 

Order  4.     TBLOTRBMATA  Beecher. 

Specialised  (through  Atremata,  ?  Obolacea),  articulate,  calcareous  Brachio- 
poda,  with  the  pedicle  opening  shared  hy  both  valves  in  earliest  shell  ed 
stages,  usually  confined  to  one  valve  in  later  stages,  and  becoming  more  or  less 
modified  by  deltidial  plates  in  advanced  growth  stages.  Brachia  supported  by 
calcareous  crura,  loops  or  spiralia. 

Superfamily  1.     RHYNCHONELLACEA   Schuchert. 

Rostrate,  primitive  Telotremata,  with  or  without  crura  for  the  support  of  the 
hrachidia.  Pedicle  foram^n  nearly  always  heneath  the  heak  and  hut  rarely  through 
a  truncate  ventral  apex.     Shells  almost  always  impunctate.     Ordovician  to  Recent. 

Family  1.     Protorhynchidae    Schuchert. 

Primitive  Rhynchonellacea  without  deltidial  plates  or  crura.     Ordovician. 

Protorhyncha  Hall  and  Clarke.  Biconvex  Rhynchonellae  with  the  fold 
and  sinus  ill-defined.  No  cardinal  process  or  dorsal  median  septum.  Surface 
with  low  radial  plications.     Ordovician  ;  North  America. 

Family  2.     Rhynchonellidae    Gray. 

Rhynchonellacea  with  crura  of  greater  or  lesser  length.  Shells  usually  plicate, 
rarely  smooth  or  spinöse.     Ordovician  to  Recent. 

Subfamily  A.     Rhynchotreminae,  novum. 

Rhynchonellids  with  a  cardinal  process.     Ordovician  to  Devonian. 

Orthorhynchula  Hall  and  Clarke.  Rhynchonellae  with  short,  straight  hinge- 
line  and  cardinal  areas  in  both  valves,  bisected  mesially  by  open  delthyria. 
Teeth  unsupported  by  dental  lamellae.  A  linear  cardinal  process  present. 
Ordovician ;  North  America. 

Rhynchotrema  Hall  (Stenochisma  Conraid,  1839;  and  Hall,  1867)  (Fig.  590). 


CLASS  II  BRACHIOPODA  397 

Thick-shelled,   often    gibbous    Rhynchomllae    with   prominent,  thick,  concave 
deltidial  plates.     Dorsal  valve  with  a  thick  median  septum,  upon  which  rests 

B 


A 


C 


Fio.  590. 
Rhynchotrema  capax  (Conrad).     Ordovician  ;    Wisconsin.      A,  Interior  of  ventral  valve  sliowing  concave 
deltidial  plates  {dp)  and  teeth  (0-    B,   Dorsal  view.     C,  Dorsal  interior  showing  cardinal  process  (j),  crural 
processes  (c)  and  dorsal  sockets  (h).    (After  Hall  and  Clarke.) 

a  linear  cardinal  process.  Crural  plates  very  broad  and  stout.  Ordovician ; 
North  America. 

Stegerhynchus  Foerste.  Exterior  as  in  Camarotoechia^  but  with  a  thin 
vertical  cardinal  process  as  in  Rhynchotrema.  Silurian ;  North  America  and 
Europe. 

Rhynchotreta  Hall.  Trihedral  Rhynchonellae  with  the  ventral  beak  acu- 
minate,  produced  and  truncate.  Pedicle  foramen  apical,  the  delthyrium 
being  completely  closed  by  the  deltidial  plates.  Dental  lamellae  and  car- 
dinal process  present.  The  prominent  dorsal  median  septum  separates 
posteriorly,  each  brauch  supporting  one  process  of  the  divided  hinge-plate. 
Silurian ;  North  America  and  Europe. 

Eatonia  Hall.  Rhynchonellae  with  large,  flabellate,  deeply  excavated 
muscular  scars  in  the  ventral  valve.  No  dental  lamellae.  Cardinal  process 
large,  resting  upon  a  short  median  septum,  and  bifurcate  at  its  summit. 
Devonian ;  North  America. 

Uncinulus  Bayle.  Like  fVilsonia,  but  with  the  hinge-plate  undivided,  and 
with  a  well-developed  cardinal  process.  Devonian ;  North  America  and 
Europe. 

(?)  Cyclorhina  Hall  and  Clarke.  May  be  of  the  Athyridae  rather  than  of 
the  Rhynchonellidae.     Devonian  ;  North  America. 

Subfamily  B.     Rhynchonellinab    Gill. 

Rhynchonellids  without  a  cardinal  process.     Silurian  to  Recent. 

Camarotoechia  Hall  and  Clarke  (Fig.  591).  Sharply  plicate  Rhynchonellae 
with  the  dorsal  median 

septum       bearing      pos-  >**.    ^  B         ,hD       ^' 

teriorly    a    short    crural 

cavity.    Cardinal  process    ^^/jl^^^^        <^|^|^4^-     ,^||||||Q^J^v 
absent ;    dental  lamellae 
present.         Silurian      to 
Lower       Carboniferous ;  p^^.  ^^^^ 

North         America  and  CamarotoecUa  congregata  {Conv&A).   Devonian  ;  New  York.    ^.Dorsal 

Für  one  aspect.     B,  C,  Dorsal  interiors  showing  hinge-plate  (hp),  rostral  Chamber 

o-iui  upc.  ^^^^  crural  processes  and  dental  sockets  (h).    (After  Hall  and  Clarke.) 

Plethorhyncha        Hall 
and  Clarke.     Large,  ponderous  Rhynchonellae,  with  almost  no  dental  lamellae 
and  110  crural  cavity.     Lower  Devonian  ;  North  America  and  Europe. 


398  MOLLUSCOIDEA  phtlüm  v 

Rhynchotetra  Weller.  Elongate,  coarsely  plicate  shells  nearest  to 
Camarotoechia.  Dental  lamellae  uniting  iiito  a  spondylium,  which  is  supported 
by  a  median  septum.     Lower  Carboniferous ;  North  America. 

Tetracamera  Weller.  Like  Camarotoechia,  but  with  rostral  dorsal  cavity 
divided  into  four  Chambers  by  the  crural  plates  and  a  median  septum.  A 
spondylium  present,  but  practically  without  septal  support.  Lower 
Carboniferous ;  North  America. 

Paraphorhynchus  Weller.  Coarsely  plicate  Rhynchonellae  with  fine 
additional  Striae.  Interior  much  as  in  Camarotoechia.  Lower  Carboniferous  ; 
North  America. 

Leiorhynchus  Hall.  Internally  like  Camarotoechia,  but  with  the  plications 
on  the  lateral  slopes  usually  faint  or  obsolete.  Devonian  to  Carboniferous. 
^ubgenus  :  Moorefieldella  Girty.  Differs  in  having  a  finely  plicate  surface. 
Lower  Carboniferous  ;  North  America. 

Wilsonia  Kayser  {Uncinulina  Bayle).  Sub-cuboidal  or  sub-pentahedral 
Rhynchonellae  with  the  low  plications  marked  anteriorly  by  fine  median  lines. 
Internally  as  in  Camarotoechia.  Silurian  to  Lower  Carboniferous.  North 
America  and  Europe. 

Hemiplethorhynchus  von  Peetz.  Very  similar  to  Camarotoechia.  Crural 
cavity  with  a  posterior  triangulär  opening.  Upper  Carboniferous ;  Altai, 
Kussia. 

Hypothyridina  Buckman  {Hypothyris  King,  non  Hubner  1822).  Sub- 
cuboidal  Rhynchonellae  with  a  very  rudimentary  dorsal  median  septum. 
Plications  as  in  Wilsonia.  Vascular  sinus  frequently  strongly  impressed  in 
the  ventral  valve.     Devonian  ;  North  America  and  Europe. 

Pugnax  Hall  and  Clarke.  Rhynchonellae  with  a  deep  dorsal  and  shallow 
ventral  valve,  and  very  prominent  fold  and  sinus.  Dental  lamellae  short ; 
no  median  septa.  Devonian  to  Carboniferous ;  North  America  and  Europe. 
Subgenus :  Ällorhynchus  Weller.  Has  decided  angular  plications  as  in 
Camarotoechia.     Lower  Carboniferous ;  North  America. 

Fugnoides  Weller.  Exterior  like  Pugnax,  with  the  internal  characters  of 
Camarotoechia.     Lower  Carboniferous  ;  North  A.merica. 

Shumardella  Weller.  Much  like  Pugnax,  but  with  a  short  dorsal  median 
septum  that  is  not  connected  with  the  hinge-plate.  Lower  Carboniferous ; 
North  America. 

Rhynchopora  King  (Rhynchoporina  QEhlert).  Plicate  Rhynchonellae  with 
the  shell  substance  punctate.  A  crural  cavity  as  in  Camarotoechia,  but  roofed 
over  by  the  hinge-plate.  Dental  lamellae  well  developed.  Eange  from 
Lower  Carboniferous  to  Permian ;  Europe  and  North  America. 

(?)  Torynifer  Hall  and  Clarke.  May  be  Rhynchonellae  with  the  crural  plates 
united  into  a  hinge-plate.  Genus  not  yet  defined.  Lower  Carboniferous ; 
North  America. 

Terebratuloidea  Waagen.  Rhynchonellae  with  very  large  apical  truncate 
foramen,  but  without  dental  plates  or  median  septa.  Carboniferous  to 
Permian ;  India. 

Rhynchonella  Fischer  (as  restricted  by  Hall  and  Clarke)  (Fig.  592,  A). 
Sub-pyramidal  pauciplicate  shells  with  the  pedicle  opening  as  in  Cyclothyris. 
Dental  lamellae  and  a  dorsal  median  septum  present.  Jurassic  and 
Cretaceous. 

Cyclothyris  M'Coy   (as    redefined  by  Buckman    in   1906)    (Figs.   592,  B, 


CLASS  II  BRACHIOPODA  399 

;ind  593).     Multiplicate  Bhynchonellae  with  the    pedicle    opening  below  the 


A,  Rhynchonella  loxia  Fisch.  Upper  Jura  ;  Moscow.  a,  b,  Profile 
and  dorsal  view,  i/j ;  c,  Internal  mould ;  d,  Anterior  view.  B, 
Cyclothyris  quadriplicata  (Quenst.).  Middle  Jura;  Bopflngen,  Wür- 
temberg. 


Fig.  593. 

A,  Cyclothyris  vespertilio 
(Brocchi).  Upper  Cretaceous ; 
Villedieu,  Touraine.  Vi-  -ß.  C. 
lacunosa  (Schloth.).  Upper  Jura  ; 
Engelhardsberg,  Franconia.  In- 
terior  of  dorsal  valve. 


ventral  beak.     Embraces  the  bulk  of  Mesozoic  Rhynchonellids.     Genotype 
Terebratula  latissima  Sowerby.     Distribution  general  in  Mesozoic  time. 

Upwards  of  700  species  of  Brachiopods  have  been  described  under  the  name  of 
Rhynchonella,  niost  of  wliich  are  found  in  Mesozoic  strata  and  are  now  to  be  referred  to  the 
genus  Cyclothyris.  But  few  Rhynchonellids  agree  with  the  genotype,  which  is  Rhynchonella 
loxia  Fischer  (Fig.  592)  from  the  Upper  Jura  of  Russia.  It  is  probable  that  there  are  no 
Rhynchonellas  in  the  Paleozoic.  Hall  and  Ciarke  and  Weller  have  shown  that  most  of  the 
American  Paleozoic  species  belong  to  other  genera.  Bittner  has  also  removed  from 
Rhynchonella  many  Triassic  species. 

Halorella  Bittner.  Sharply  plicated  Bhynchonellae  with  a  median  sinus 
on  both  valves.     Alpine  Trias. 

Austriella  Bittner.  Small  triangulär,  usually  smooth-shelled  Bhynchonellae 
without  prominent  fold  and  sinus.     Alpine  Trias. 

Norella  Bittner.  Like  Austriella,  but  with  prominent  anterior  fold  and 
sinus.     Alpine  Trias. 

Bhymhonellina  Gemmellaro.  Transverse  Bhynchonellae  with  fine  radial 
Striae.  Cardinal  margin  nearly  straight,  with  a  low  concave  ventral  area. 
Crura  very  long,  ventrally  curved.  Median  septum  of  dorsal  valve  faint. 
Jura  ;  Sicily  and  the  Alps. 

Dimerella  Zittel.  Small  plicate  shells  with  a  high  umbo  and  a  straight 
hinge-line.  Delthyrium  large,  with  linear  deltidial  plates.  Dorsal  valve  with 
a  high  median  septum  extending  to  the  ventral 
valve.     Alpine  Trias. 

Peregrinella  (Ehlert.  Large,  strongly  plicate 
Bhynchonellae  without  fold  or  sinus.  Cardinal 
area  well  developed.     Cretaceous  ;  Europe. 

Hemithyris  d'Orb.  (Fig.  594).  Smooth  or 
faintly  plicate  Bhynchonellae  with  a  high  ventral 
beak  and  open  delthyrium.     No  dental  plates.  .       Fif=-  5^^. 

_-,  j.  ./  Jlemi thyris  pstttacea  (Chem.).    Recent 

Kecent.  Mediterranean.     Vi. 


400  MOLLUSCOIDEA  phylüm  v 

Basiliola   Dali.       Deep-sea   forms    resembling    Hemithyris,    but    with    the 
deltidial  plates  united  into  a  spondylium-like  plate.     Eecent. 

Frieleia  Dali.     Resembling  Heynithyris,  but  with  a  small  dorsal  spondylium. 
Recent ;  American  Pacific. 

Atretia  Jeffreys  (Cryptopora  Jeffreys  1869,  non  Cryptoporus  Motoch  1858; 
Neatretia  CEhlert).  Small,  smooth  sbells  with  an  acute  and 
prominent  open  ventral  beak.  Dental  plates  and  a  high, 
mesially  situated,  dorsal  septum  present.     Recent. 


Subfamily  C.      Acanthothyrinae,  novum. 

Ehynchonellids  with  a  spinöse  surface. 

Acanthothyris  d'Orb.  (Fig.  595).  In  general  like  Hemi- 
(Schioth.).  Middie  tfiyns,  Dut  witü  well-developed  dental  plates.  Jurassic  to 
pSifate'^'"^'^^^''   Recent ;  Europe  and  Japanese  sea. 


Fio.  595. 
Acanthothyris  spinosa 


Superfamily  2.     TEREBRATULAOEA  Waagen. 

Specialised  Telotremata  with  the  brachia  supported  hy  calcareous,  primitive  or 
metamorphosed  loops.     Shell  strudure  always  pundate.     Devonian  to  Recent. 

Division  A.     Terebratuloids. 

Terebratulacea  with  the  loops  unsupported  hy  a  median  dorsal  septum  at  any  stage 
of  growth.     Brachial  cirri  directed  outwards  in  larval  stages. 

Family  1.     Centronellidae  Hall  and  Clarke. 

Primitive  Terebratuloids  with  short  loops  developing  dired  and  composed  of  two 
descending  lamellae,  uniting  in  the  median  line  and  forming  a  broad  arched  plate. 
Shells  smooth,  faintly  striate  or  rarely  plicate.     Devonian  to  Triassic. 

This  family  comprises  the  simplest  of  all  Terebratuloids,  and  from  it  are  probably 
descended  the  other  loop-bearing  f amilies. 

Centronella  Billings    (Fig.  596).     Commonly  small,  smooth,  plano-convex 

or  concavo-convex  shells,  with  the  descend- 
ing branches  of  the  loop  broadening 
rapidly  anteriorly,  and  uniting  in  a  tri- 
angulär, mesially  ridged  plate.  Hinge- 
plate  perf orate.  Devonian ;  North  America, 
Amphigenia  Hall  (Enantiosphen  Whid- 
borne).  Elongate-ovate,  high-shouldered 
Shells  without  median  fold  or  sinus. 
Fig.  596.  *'  Surface    with    concentric   growth    varices 

Centronella  glansfagea  (Hall).    Devonian  ;  Brie    and  f aint  radial  Striae.       Dorsal  Valve  with 
County,  N.Y.    ^,  £,  Profile  and  dorsal  aspect,  ^/..         ^  ■,  i      .      i  •  i    j_  j-        j_     ^ 

c,  Loop,  eniarged.  a  large  sub-quadrate  ninge-plate  periorated 

by  the  visceral  foramen  and  without  a 
cruralium.  Middie  Devonian;  North  and  South  America,  France  and 
Germany. 

Eensselaeria  Hall.  Ovate  or  elongate-ovate  striate  Terebratuloids.  The 
descending  branches  of  the  loop  diverging  for  a  short  distance,  thence  acutely 


CLASS  II  BRACHIOPODA  401 

beut,  converging,  and  uniting  in  an  elongate  triangulär  plate,  which  on  the 
posterior  margin  gives  off  a  small,  posteriorly  directed,  rod-like  process. 
Hinge-plate  large  and  often  much  thickened.  Thick  dental  plates  present. 
Lower  Devonian ;  North  America  and  Germany. 

Lissopleura  Whitfield.  Strongly  plicate  Bensselaeriae,  with  the  dental 
plates  uniting  to  form  a  short  rostral  cavity.  Lower  Devonian  ;  North 
America. 

Beachia  Hall  and  Clarke.  Lentiform,  finely  striated  Bensselaeriae  with  the 
lateral  margins  of  the  valves  inflected,  the  anterior  plate  of  the  brachidium 
broader,  and  the  rod-like  process  longer.     Lower  Devonian  ;  North  America. 

Newberria  Hall  (Bensselandia  Hall).  Resembling  Bensselaeria  externally, 
but  without  the  striate  surface.  Interior  strongly  marked  by  muscular  scars 
and  vascular  sinuses.     Devonian  ;  North  America  and  Europe. 

Chascothyris  and  Deiikmannia  Holzapfel.     Devonian  ;  Germany. 

OrisJcania  Hall  and  Clarke.  Large  Centronellae  with  a  continuous  hinge- 
plate  bearing  a  thin  vertical  spur  or  cardinal  process.  Lower  Devonian ; 
North  America. 

Selenella  Hall  and  Clarke.  Comprises  biconvex  terebratuliform  shells 
with  a  Centronella-like  loop,  but  the  triangulär  plate  not  mesially  thickened. 
Devonian ;  North  America. 

Bomingerina  Hall  and  Clarke.  Small  biconvex  Centronellae  with  the 
median  ridge  on  the  anterior  plate  of  the  loop  elevated  into  a  high  vertical 
lamella  almost  touching  the  ventral  valve  and  extended  both  anteriorly 
and  posteriorly.     Devonian  to  Lower  Carboniferous  ;  North  America. 

Trigeria  (Bayle)  Hall  and  Clarke.  Plicated,  plano-convex  Centronellae. 
Devonian ;  France,  Brazil  and  North  America. 

(?)  ScaphioGoelia  Whitfield.  Very  large,  plicate,  piano-  or  concavo-convex, 
Cenironella-\ike  shells  exteriorly.  Loop  unknown.  Shell  substance  fibrous, 
impunctate.     (?)  Devonian  ;  South  America. 

Juvavella  Bittner.  Small,  smooth,  biconvex  shells,  with  a  very  short 
Centronella-\\kQ  loop.     Alpine  Trias. 

Juvavellina  and  Dinarella  Bittner.  Alpine  Trias.  Aspidothyris  Diener. 
Trias  of  India. 

Nucleatula  Bittner.  Like  Juvavella^  but  having  a  longer  loop  with  a  well- 
developed  and  fimbriated  vertical  median  plate.     Alpine  Trias. 

Family  2.     Stringocephalidae  King. 

Specialised  Devonian  Terebratuloids  with  a  long  loop,  follomng  the  margin  of  the 
dorsal  valve,  and  not  recurved  in  front.  Development  direct.  Prohahly  no  median 
coiled  arm.     Shells  smooth.     Devonian. 

Stringocephalus  Defr.  (Fig.  597).  This,  the  solitary  genus  of  the  family,  is 
limited  to  the  Devonian  of  Europe  and  North  America. 

Family  3.     Terebratulidae  Gray. 

Terebratuloids  developing  originally  a  Centronella-like  loop,  and  thence  by  a  short 
series  of  metamorphoses  resulting  at  maturity  in  a  free  loop  of  varying  form 
Devonian  to  Recent. 

VOL.  I  2  D 


402 


MOLLUSCOIDEA 


PHYLUM   V 


Subfamily  A.     Megalanterinae  Waagen. 

Faleozoic  Terebratulidae  with  a  longlloop  giving  off  ascending  hranches. 
smooth.     Devonian  to  Carboniferous. 


Shell 


Fig.  597. 
Stringocephalus  burtini  Defr.     Devonian  ;  Paffrath,  near  Cologne.    A,  Side-view,  2/3  natural  size.     B,  Greatly 
reduced  diagram  showing  brachidium  and  median  septa.     C,  Young  speclmen  with  large  delthyriurn  and  deltidial 
plates.    D,  Interior  of  dorsal  valve,  natural  size,  partly  restored.    a,  Adductors  ;  c,  Crura  ;  d,  Dental  sockets  ; 
l,  Loop  ;  pr,  Cardinal  process  ;  s,  Median  septum. 

Megalanteris  (Ehlert  (Meganteris  Suess).  Large,  smooth,  equally  biconvex, 
sub-oval  Shells,  with  the  long  convergent  jugal  processes  of  the  loop  extending 
beyond  the  connecting  band  of  the  ascending  branches.  Devonian ;  Europe 
and  North  America. 

Cryptonella  Hall.  Elongate  oval  shells  with  short  jugal  processes. 
Devonian  to  Lower  Carboniferous ;  North  America,  England  and  Bohemia. 

Harttina  Hall  and  Clarke.  Centronella-like  shells  with  a  high  dorsal 
median  septum  and  the  descending  branches  of  the  loop  laterally  fringed  with 
irregulär ly  set  spinules.     Carboniferous  ;  North  America  and  Brazil. 

(?)  CryptacantUa  White  and  St.  John. 
Upper  Carboniferous  ;  North  America. 

Subfamily  B.     Dielasmatinae,  novum. 


Berived  Faleozoic  Terebratulidae  with 
short  loops.  Often  there  are  cruralia  present. 
Shells  smooth  or  coarsely  plicate.  Devonian 
to  Permian. 

Eunella  Hall  and  Clarke.  Like  Dielasma 
but  without  a  cruralium.  Devonian ;  North 
America. 

Dielasma  King  (Epithyris  King,  non 
Phillips)  (Fig.  598).  Dental  lamellae 
strong.  „To  the  divergent  crural  plates  is  attached  a  shallow,  often  quite  long, 
free  or  sessile  cruralium.     Devonian  to  Permian  ;  Europe,  India  and  America. 


Dielasma elongatum  (Schloth.).  Permian;  Hum 
bleton,  England.  A,  Dorsal  and  anterior  views 
1/1.  B,  Interior  of  conjoined  valves,  greatly  en 
larged  (after  Davidson). 


CLASS  TT 


BRACHIOPODA 


403 


Girtyella  Weller.  Like  Dielasma,  but  the  cruralium  is  supported  by  a 
septum.     Lower  Carboniferous  ;  North  America. 

Dielasmoides  Weller.  Like  Girtyella,  but  with  septal  plates  instead  of 
crural  lamellae.     Lower  Carboniferous  ;  North  America. 

Cranaeiui  Hall  and  Clarke.  Dental  lamellae  strong.  Socket  plates 
uniting  into  a  hinge-plate  which  is  posteriorly  perf orate ;  no  cruralium. 
Devonian  and  Lower  Carboniferous.  Subgenera  :  Hamburgia  and  Dielasmella 
Weller.     Lower  Carboniferous,  North  America. 

Dielasmina  Waagen.     Plicated  Dielasmids.     Carboniferous  ;  India. 

Beecheria  Hall  and  Clarke.  Like  Dielasma,  but  without  dental  lamellae ; 
cruralium  completely  sessile.     Carboniferous  ;  North  America  and  India. 

Bowleyella  Weller.     Both  valves  with  median  septa.     Lower  Carboniferous  ; 


North  America. 

Heterelasma  Girty. 


Smooth  Dielasmids  with  a  ventral  fold  and  a  dorsal 


smus. 
Texas. 


Median  septa  in  both  valves.     Hinge-plate  rudimentary.     Permian  ; 


Hemiptychina  Waagen.  Plicated  Dielasmids  without  dental  plates.  Carboni- 
ferous to  Permian ;  India. 

Notothjris  Waagen  (Eostranteris  Gemmellaro).  Coarsely  plicate  biconvex 
Shells  with  a  perforate  hinge-plate  as  in  Centronella.     Permian ;  India. 


Subfamily  C.     Terebratülinae  Dali. 


A  median  unpaired  coiled  arm 


Post-Paleozoic  TerehratuUdae  with  a  short  loop. 
exists  in  Recent  genera.     Triassic  to  Recent. 

Terehratula   Müller    1776   (as    redefined  by  Buckman    1907)   (Fig.   599). 
Genotype    Anomia    terehra- 
tula Linn.    Pliocene.    Large 
biplicate  shells  of  the  Ter- 
tiary  of  Europe. 

Musculus  Quenstedt. 
Buckman  states  that  this 
term  will  be  useful  for  the 
Cretaceous  biplicate  species. 
Genotype  Terehratula  acuta 
Quenst.     Europe. 

Epithyris  Phillips,  non 
King.  Buckman  uses  this 
genus  for  a  small  group 
of  Jurassic  biplicate  forms. 
Genotype  Terehratula  maxil- 
lata  Sowerby.     Europe. 

Ehaetina  and  Zugmeyeria  Waagen.  These  genera  comprise  biplicate 
forms.     Trias ;  Europe. 

Pygope  Link  (Diphyites  Schröter)  (Fig.  600);  Antinomia  Catullo ;  and 
Pygites  de  Haan  (as  redefined  by  Buckman  1906).  Three  independent  genera, 
according  to  Buckman,  with  the  shells  originally  bilobed,  the  two  lobes  often 
uniting  anteriorly  in  adult  specimens,  but  leaving  posteriorly  a  median 
hollow  Space  passing  through  both  valves.  Developed  out  of  a  Glossothyrid- 
like  form.     Jurassic  ;  Europe. 


Fig.  599. 

Terehratula  phillipsi 
Morris.  Middle  Jura ;  Egg, 
near  Aarau,  Switzerland.  i/i. 


Pygope  diphya  (Colonna).  Tithonian  ; 
Trent,  Tyrol.     l/l- 


404 


MOLLUSCOIDEA 


THYLUM  V 


Fropygope  Bittner.     Triassic  ;  Europe. 

Didyothyris  Douvillö  (Fig.  601);  Glossotky r is  IdoviYiWii  (Fig.  602);  Pseudo- 
glossothyris  Buckman ;  (?)  DiscuUna  Deslong.     All  from  the  European  Jura. 
Liothyrina  Q^hlert  (Liothyris  Douville)  (Fig.  603).     Tertiary  to  Recent. 
Terebratulina  d'Orb.  (Fig.  604).     Jurassic  to  Recent ;  distribution  general. 
Chlidonophora  Dali.     Deep-sea  Terebratulinae.     Recent. 


Subfamily  D.      Dyscoliinae  Beecher. 

Post-Paleozoic   Terebratulidae  with  the  loop  short  and  no  coiled  median  arm. 
(?)  Cretaceous,  Recent. 

B  C 


Fig.  602. 

Glossotliyris  nucleata  (Schloth.). 
Upper  Jura ;  Bngelhardsberg, 
Franconia.     i/j. 


Didyothyris  coarctata  (Park.).     Great  Oolite  ;  Bath,  England.     A-C,  Tliree 
Views  of  the  natural  size.    D,  Portion  of  outer  surface,  enlarged. 


Fig.  603. 
Liothyrina  vitrea  (Linn.).    Recent ;  Mediterranean.    i/^. 


Fig.  604. 

Terebratulina  suh- 
striata  (Schloth,). 
Upper  Jura  ;  Nat- 
theim,  Würtem- 
berg.    Vi- 


Dyscolia  and  Eucalathis  Fischer  and  (Ehlert.     Recent. 
(?)  Ägulhasia  King.     Small  TerehratuUna-like  shells  with  the  ventral  beak 
greatly  elevated  and  a  triangulär  false  cardinal  area.     Cretaceous  to  Recent. 


Division  B.     Terebratelloids. 

Terebraiulacea  with  the  loop  supported  hy  a 


dorsal  septum  throughout 
life,  or  only  in  the  younger  stages.     Brachial  cirri  direded  inwards  during  larml 
This  section  has  two  phyla  having  a  common  origin,  now  geographically 
'  in  two  provinces,  one  austrat,  the  other  horeal. 


Family  1.     Terebratellidae  King  (emend.  Beecher). 

Terebratelloids  with  the  loop  in  the  higher  genera  composed  of  two  primary  and 
two  secondary  lamellae,  passing  through  a  series  of  distind  metamorphoses  white 
attached  to  a  dorsal  septum.     Devonian  to  Recent. 


I 


BRACHIOPODA 
Subfamily  A.      Megathyrinae  Dali  (emend.  Beecher). 


405 


Terehratellidae  in  luhich  the  loop  is  composed  of  descending  hranches  only,  passing 
in  the  highest  genus  through  stages  correlative  with  Gwynia,  Argyrotheca  and 
Megathyris.  The  lower  genera  do  not  complete  the  series,  The  original  stock  for  the 
two  following  suhf amilies.     Jurassic  to  Recent. 

Gwynia  King.     Minute,  elongate-oval,  smooth  shells  with  a  short,  nearly 
straight    hinge-line.       Neither    septa 
nor  loop.     Brachia  primitive,  consist- 
ing  of  a  circlet  of  cirri.     Eecent. 

Zellania  Moore.  Minute  shells 
without  a  loop,  but  with  a  median 
septum  in  each  valve.    Lias  ;  Europe. 

Argyrotheca  Dali  (Cistella  Gray) 
(Fig.  605).  Externally  like  Mega- 
thyris, but  without  lateral  septa. 
Cretaceous  to  Recent ;  Europe. 

Megathyris    d'Orb.    {Argiope    Des- 
long.)    (Fig.    606).      Transversely    elongate,    plicate    shells    with    long    and 
straight   hinge-line.     Dorsal    valve  with    three    or    five   septa,   causing    the 
brachidium  to  have  four  lobes.     Jura  to  Recent ;  Europe. 


Fio.  605. 

Argyrotheca  bilo- 

cularis       (Desl.). 

Cfinomanian  ;    La 

Manche,     i/i. 


Megathyris  (lecollata  (Chem.). 
Cent;    Mediterranean.     Interior  of 
dorsal  valve.    4/j  (after  Davidson). 


Subfamily  B.     Dallininae  Beecher. 

Terehratellidae  with  the  loop  composed  of  descending  and  ascending  lamellae, 
passing  in  the  highest  genera  through  metamorphoses  comparable  to  the  adult  structure 
of  Platidia,  Ismenia,  Muehlfeldtia,  Terebratalia,  and  Dallina.  The  lower  genera^ 
therefore,  do  not  progress  to  the  final  stages.  Jura  to  Recent.  Recent  genera 
restricted  to  boreal  seas. 

Platidia  Costa  {Morrisia  Davidson).  Small,  smooth,  biconvex  shells  with 
a  large  pedicle  opening  common  to  both  valves.     In  the  dorsal  valve  there 

is  a  high  vertical 
plate  to  which  are 
attached  the  de- 
scending branches; 
ascending  branches 
not  represented. 
Recent. 

Ismenia  King. 
Coarsely  plicate 
Shells  with  the  loop 
consisting  of  fim- 
briate  descending 
branches  and 
simple  ascending 
branches.     Jura. 


Fin.  607. 


Trigonellma  pectuncula  (Schloth.)-  Upper 
Jura ;  Engelhardsberg,  Franconia.  A-C\ 
Shell  of  the  natural  size.  D,  E,  Two.views 
of  loop,  enlarged. 


Fio.  608. 

Mvehlfeldtia  truncata  (Gemni.). 
Recent ;  Mediterranean.  Interior 
of  dorsal  valve.  c,  Crura;(Z,  Dental 
socketa  ;  e,  Jugum  ;  /,  l,  Ascending 
and  descending  branches  of  loop ; 
p,  Process  attached  to  median  sep- 
tum ;  pr,  Cardinal  process ;  S, 
Median  septum. 


Trigonellina  Buckman  (Fig.  607).     Jurassic  ;  Europe. 
Muehlfeldtia  Bayle  (Megerlea  King)  (Fig.  608).     Jura  to  Recent. 


406 


MOLLUSCOIDEA 


PHYLÜM  V 


Frenulina  Dali.     Subgenus  of  Muehlfeldtia.     Recent. 

Terebratalia  Beecher.  Shell  when  adult  like  Terebratella,  but  passing 
through  a  quite  different  series  of  metamorphoses.     E-ecent. 

Dallina  Beecher.  Elongate  Terehrataliae  with  a  small  cardinal  process  and 
a  ventral  median  sinus.     Tertiary  to  Recent. 

Macandrevia  King.  Elongate  Terehrataliae  with  dental  plates  and  no 
cardinal  process.     Recent.     A  subgenus  of  Budesia,  according  to  Dali. 

Laqueus  Dali  (Frenula  Dali).  Like  Terebratalia,  but  the  loop  has  two 
lateral  processes  connecting  the  ascending  and  descending  branches.     Recent. 


Fig.  609. 
A,  B,  Kingeim  lima  (Defr.).  Cretaceous  ;  England.  Lateral  and  frontal  aspect  of  loop,  enlarged  (after 
Davidson).  C,  Specimen  froni  the  Galeritenpläner  of  Salzgitter,  i/^.  D,  Bxternal  surface,  enlarged.  E,  F, 
Kingena  friesensis  (Schriifer).  Upper  Jura  ;  Gruibingen,  Würtemberg.  i/i.  c,  Crnra  ;  d,  Dental  sockets  ; 
e,  Jugum ;  /,  l,  Ascending  and  descending  branches  of  loop  ;  j,  Cardinal  process  ;  r,  Point  of  recurvatiire  of 
loop  ;  S,  Median  septum. 

Kingena  Davidson  (Kingia  Schloenbach)  (Fig.  609).     Cretaceous ;  Europe 
and  North  America. 

PseudoJcingena  Böse  and  Schlosser.     Cretaceous  ;  Europe. 

Lyra  Cumberland  (Terebrirostra  d'Orb.)  (Fig.  610).     Cretaceous;  Europe. 


Fio.  610. 

Lyra  neocumiensis  (d'Orb.). 
Lower  Cretaceous ;  Morteau, 
Doubs.     Natural  size. 


Fig.  611. 


A,  Trigonosemus  elegans  Koenig.  White  Chalk  ; 
England.  Interior  of  dorsal  valve,  enlarged  (after 
Davidson).  B,  T.  palissyi  Woodw.  Upper  Cretace- 
ous ;  Ciply,  Belgium.     i/i. 


Trigonosemus  Koenig  (Fissurirostra,  Fissirostra  d'Orb. ;  Delthyridea  King) 
(Fig.  611).     Cretaceous;  Europe. 

ificro^^m  Deslongchamps  (Fig.  612);  Orw^Mk  Deslongchamps  ;  Zeilleria 
Bayle.     Jurassic  genera  ;  Europe. 

Äulacothy ris  DovcviW^  (¥ig.  613).  Trias  to  Cretaceous;  Europe.  Eudesia 
King ;  Orthotoma  and  Trigonella  Quenst. ;  Flabellothyris  Deslong.    Jura  ;  Europe. 


!LäSR  II 


BRACHIOPODA 


407 


Fimbriothyris  and  Epicyrta  Deslong.     Jura.     Camerothyris  Bittner.     Trias. 

Cincta  Quenstedt.  Jura.  Antiptychina 
Zittel.  Jura.  Plesiothyris  Douvillö.  Jura. 
These  are  all  European  genera. 

l\^^  //  ^  Jf     \\         1  Hynniphoria  ^uess;  ICruratula  Bittner; 

I  ^  ^  '  *  /\  \\  *    1  Orthoidea  Friren. 


Fio.  612. 

Microthyrls  lagenalls  (Schloth.).     Cornbrash 
Rushden,  England.     Vi  (after  Davidson). 


Fic.  613. 

Aulacothyris  resupinata  (Sow.).     Middle  Lias  ;  Ilminster, 
England  (after  Deslongchamps). 


Siibfamily  C.     Magellaniinae  Beecher. 

Terebratellidae  with  the  loop  composed  of  descending  and  ascending  branches, 
passing  in  the  higher  genera  through  metamorphoses  comparable  to  the  adult  structure 


Fig.  614. 

Mayas  pumilus  Sow.  White 
Chalk  ;  Menden,  near  Paris.  A,B, 
Shell,  i/i.  Ü,  Vectical  section.  D, 
Interior  of  dorsal  valve. 


Fio.  615. 
Coenothyris  vulgaris  (Scliloth.).     Muschelkalk ;   Wiirzbnrg.     A, 
Dorsal  and  anterior  views,  i/i-     -ß>  Loop  enlarged  and  restored 
from  sections  treated  with  acid  (parfcly  after  Koschinsky). 


of  Bouchardia,  Magas,  Magasella,  Terebratella  and  Magellania.  The  lower  genera 
become  adult  before  reaching  the  terminal  stages.  Jura  to  Recent.  Recent  genera 
restricted  to  austral  seas. 

Bouchardia  Davidson  (Fachyrhynchus  King).     Recent ;  South  Atlantic. 

Magas  Sowerby  (Fig.  614).  Cretaceous ;  Europe.  Pachymagas  von 
Ihering.  Tertiary ;  Patagonia.  Magasella  Dali.  Recent.  Coenothyris 
Douville  (Fig.  615).     Trias;  Europe. 


408 


MOLLUSCOIDEA 


PHYLÜM  V 


Magellania  Bayle  {Wa 


Terehratella  d'Orb.   {Delthyris  Menke ;   Ismenia  King ;   Waltonia  Davidson) 
(Fig.  616).     Jura  to  Recent. 

King;  Neothyris  Douville)  (Figs.  534,  535, 

617).     Jura  to  Recent. 

Bhynchorma  (Ehlert.  Cre- 
taceous.  Megerlina  Deslong- 
champs.  Recent.  Kraussina 
Davidson  (Kraussia  Davidson, 
non  Dana  1852).  Recent. 
Mannia  Dewalque.  Miocene. 
(?)  Bhynchora  Dalman.  Cretace- 
ous. 


Superfamily  3. 
SPIRIFERACEA  Waagen. 

Telotremata    with    the    adult 
j^^    brachia    supported   hy   calcareous 


Fig.  616. 

Terehratella       dorsata 
(Lam.).     Recent;  Chili. 

lA. 


Fig.  61^ 


Magellania  flavescens  (Val.).      ^.„  .  .      7 .  r^ 

Cent  ;■  Australia.     Interior  of  dorsal    Spiral    lamellae    OT    Spiralia.       Or- 
valve,  somewhat  enlarsed.  j       •    •         j.      t 

dovician  to  Jurassic. 

The  Spiriferacea  are  abundantly  represented  from  the  Silurian  tö  the  Carboni- 
ferous,  during  which  time  the  jugum  undergoes  many  and  often  rapid  changes.  The 
brach idia  in  Zygospira  are  known  to  begin  with  a  Gentronella-like  loop,  as  in  the 
primitive  Terebratulacea. 


Family  1.     Atrypidae  Gill. 

Divergent  Spiriferacea  with  the  crura  directly  continuous  with  the  primary 
lamellae,  which  diverge  widely  and  have  the  spiral  cones  hetween  them.  Jugum 
simple,  complete,  or  incomplete.     Ordovician  to  Devonian. 


Subfamily  A.     Zygospirinae  Waagen. 

Primitive  Atrypidae  with  a  simple  jugum,  either  posteriorly  or  anteriorly 
directed.  Spiralia  with  apices  directed  tovjard  the  median  dorsal  region.  Ordovician 
to  Devonian. 


Zygospira  Hall  (Anazyga  Davidson ;  Orthonomaea 
and  Schuchert ;  Protozyga  Hall  and  Clarke)  (Fig. 
618).  Like  Atrypa,  but  small,  and  the  spirals 
composed  of  fewer  coils.  Jugum  a  simple  con- 
necting  band,  situated  rather  anteriorly.  Sur- 
face  sharply  plicate,  never  lamellose.  Ordovician 
and  Silurian  ;  North  America. 

Catazyga  Hall  and  Clarke.  More  rotund  and 
finely  striated  than  Zygospira,  with  the  complete 
jugum  decidedly  posterior  in  position.  Ordo- 
vician and  Silurian  ;  North  America. 

Atrypina  Hall  and  Clarke.  Primitive  Atrypae 
with  few  plications,  and  but  three  or  four 
volutions  in  each  spiral.     Jugum  as  in  Atrypa, 


Hall :   Hallina  Winchell 


Fig.  618. 


Zygospira  modeffta  Hall.     Ordovician 
Cincinnati,  Ohio.    «Vi  (after  Hall). 


CLASS  II 


BRACHIOPODA 


409 


but    contiriuous.       Late    Ordovician    to    Devonian ;     North    America    and 
Euroj^e. 

Glassia  Davidson  (Fig.  619).     Small,  smooth  shells,  with  the  apices  of  the 
laterally  compressed   spirals  situated  at   the  centre   of 
the  brachial  cavity.     Jugum  similar  to  that  of  Atrypina. 
Ordovician  to  Devonian  ;  Europe  and  America. 

Subfamily  B.     Atrypinae  Waagen. 

Terminal  Atrypidae  with  the  jugum  situated  extremely 
posteriorly,  complete  in  young  stages,  but  at  maturity  dis- 
continuous.  Spiralia  dorso-medially  directed,  Late  Ordo- 
vician to  Devonian. 

Atrypa    Dalman    {Spirigerina    d'Orb.)     (Fig.    620).  sifuS";  WeÄÄS: 
Shell  radially  plicated,  usually  with  lamellar  expansions  J"^'^"'g  of  dorsal  vaive.   s/^ 
or  hollow  spines.     Spirals    introverted,  dorso-medially 
directed.      Jugum   extremely  posterior  in   position,  and  complete  in    young 


Fio,  619. 


Fig.  620. 

Atrypa  reticularis  (Linn.).  Middle  Devonian;  Gerolstein.  Eifel.  ^,  Umbonal  aspect  of  adultspecimen.  B, 
Ventral  aspect  and  profile  of  young  shell.  C,  Interior  of  dorsal  valve,  showing  spiralia,  crnra,  and  jugum. 
D,  Ventral  valve,  showing  muscular  and  vascular  impressions.  a,  Adductors  ;  c,  Diductors  ;  d,  Deltidial  plates  ; 
o,  Ovaries  ;  p,  Pedicle  muscle. 

stages ;  but  mesially  absorbed  at  maturity.  Widely  distributed  in  the  late 
Ordovician,  Silurian  and  Devonian. 

Grueneivaldtia  Tschernyschew.  Atrypa-like  shells,  but  with  the  relative 
convexity  of  the  valves  reversed.     Devonian  ;  .Russia. 

(?)  Karpinshya  Tschernyschew.  Elongate,  Atrypa-like  shells,  with  a  median 
dorsal  septum.     Devonian  ;  Russia. 

(?)  Glintonella  Hall  and  Clarke.     Silurian  ;  North  America. 


Fio.  621. 

Daiiianavicitla (ßow.).    Silurian;  Lud- 
low,  Shropshire.     s/o  (after  Davidson). 


Subfamily  C.     Dayiinae  Waagen. 

Derived  Atrypidae  with  the  jugum  drawn  out 
posteriorly  into  a  simple  short  process.  Spiralia 
laterally  directed. 

Dayia  Davidson  (Fig.  621).  Small  smooth 
shells,  with  the  jugum  situated  anteriorly,  and 
drawn  out  posteriorly  into  a  simple  short  process. 
Spiralia  laterally  directed.     Silurian  ;  Europe. 


410  MOLLUSCOIDEA  phylüm  v 

Family  2.      Oyclospiridae,  noviim. 

Primitive  Spiriferacea  with  the  crura  directly  continuous  with  the  hases  of  the 
primary  lamellae,  which  are  closely  set  and  nearhj  parallel.  Spiralia  very  dightly 
introverted  and  of  hut  three  or  less  volutions  ;  no  jugum  present.     Middle  Ordovician. 

Cyclospira  Hall  and  Clarke.  Small,  smooth,  rostrate  shells,  with  a  deep 
ventral  and  a  shallow  dorsal  valve.  Dorsal  hinge-plate  supported  by  a  median 
septum.     Middle  Ordovician  ;  North  America. 

Family  3.     Spiriferidae  King. 

Derived  Spiriferacea  with  the  crura  directly  continuous  with'  the  hases  of  the 
primary  lamellae,  which  are  situated  hetween  the  laterally  directed  spiralia.  Jugum 
simple,  complete,  or  incomplete.     Silurian  to  Jurassic. 

Subfamily  A.      Spiriferinae,  novum. 

Spiriferidae  with  the  jugum  discontinuoiis  at  maturity,  represented  by  two  short 
jugal  processes,  one  attached  to  each  primary  lamella.  Shell  structure  with  scattering 
perforations,  hut  never  regularly  punctate.     Silurian  to  Permian. 

Spirif er  Bowerhy.  This  name  has  been  made  to  cover  a  vast  number  of 
Paleozoic  Brachiopods  having  a  more  or  less  alate  form,  a  multiplicate  surface, 
and  terminally  directed  spiralia.  Yarious  attempts  have  been  made  to  group 
the  species  into  phyletic  series,  but  as  there  is  present  more  or  less  of  homoeo- 
morphic  development  a  completely  satisfactory  arrangement  is  not  yet  at 
band.     The  following  scheme  is  of  tentative  character. 

Spirifer  Sowerby  sensu  stricto  {Fusella  M'Coy)  (Fig.  622,  A).  Transverse, 
usually  alate  Spirifers  with  the  entire  shells  more  or  less  closely  plicate ; 
plications  simple  or  dichotomous.  Short  dental  plates  developed,  but  no  high 
median  septa  in  either  valve.  Genotype  Anomites  striatus  Martin.  Section 
Aperturati  Hall  and  Clarke.     Devonian  to  Permian  ;  distribution  general. 

Section  Spiriferella  Tschernyschew.  ,  A  group  of  subquadrate  Spirifers 
suggesting  S.  cameratus,  but  with  the  surface  finely  papillose.  Ventral  shells 
very  thick,  with  strong  dental  plates.  Upper  Carboniferous ;  Urals,  Alaska 
and  North  America. 

Section  Trigonotreta  Koenig.  Early,  coarsely  plicate  Spirifers  in  which 
the  plications  are  simple  and  not  dichotomous.  Genotype  S.  aperturatus 
Schlotheim.     Devonian  ;  Europe  and  America. 

Section  Choristites  Fischer  (Fig.  622,  D).  Quadrate  Spirifers  that  are 
decidedly  multiplicate  and  have  long  dental  plates.  Genotype  S.  mosquensis 
Vern.     Carboniferous  ;  Europe  and  America. 

Section  Dzieduszychia  Siemiradz.  Large  short-hinged  Spirifers  with  a 
plicate  sinus  in  either  valve.  Genotype  Terehr.  hielcensis  Roemer.  Middle 
Devonian;  Europe. 

Section  Brachythyris  M'Coy.  Rounded,  tumid,  short-hinged  Spirifers,  with 
broad  and  depressed  plications  tending  to  be  absent  on  fold  and  sinus. 
Genotype  S.  ovalis  Phillips.     Carboniferous  ;  Europe  and  America. 

Subgenus  Adolfia  Gürich  (Fig.  622,  B,  G).  Quadrate  to  alate,  multiplicate 
but  not  dichotomously  plicate  Spirifers,  that  have  no  plications  on  fold  or 
sinus '  (rarely,  the  fold  is  bilobed  and  then  there  may  be  a  plication  in  the 
sinus).  Surface  pustulose  or  finely  pustulo-striate.  Dental  plates  short ;  no 
ventral    median    septum.      Genotype    aS^.    deflexus   Roemer.     Section    Ostiolati 


HP 

^Hlärs  II 


BEACHIOPODA 


411 


Hall  and  Clarke.     Essentially  Devonian  but  persisting  into  Carboniferous ; 
distribution  general. 

Subgenus  Syringothjris  Wiiichell  (Syringopleura  Schachert).  Like  Adolfia^ 
'but  usually  Avith  large  and  erect  ventral  cardinal  areas,  and  always  with  an 
internal  tube  or  syrinx,  situated  in  the  delthyrium.  Upper  Devonian  and 
Lower  Carboniferous  ;  widely  distributed. 


Fig.  622. 

A,  Spirifer  striatus  (Martin).  Lower  Carboniferous ;  Ireland.  Portion  of  dorsal  valve  removed,  showing 
spiralia,  3/^  (after  Davidson).  B,  S.  (Adolfia  ?)  speciosus  (Schlotli.).  Devonian  ;  Eifel.  Vi-  f'.  S.  (Adolfia  ?) 
macropterus  (Goldf.).  Devonian  ;  Coblenz.  Mould,  i/].  D,  S.  (Choristites)  mosqnensis  Veni.  Middle  Carboni- 
ferous ;  Moscow.     E,  Same,  interior  of  ventral  valve,  i/i.    2'.  Pseudodeltidium  ;  x,  Dental  plates. 

Subgenus  Syringospira  Kindle.  Like  Syringothyris,  but  with  a  striate  fold 
and  sinus.     Upper  Devonian  ;  New  Mexico. 

Subgenus  DeUhyris  Dalman.  Small  early  Spirifers  that  are  coarsely  plicate 
except  on  the  fold  and  sinus.  Surface  lamellose ;  the  imbricating  lamellae 
marked  with  very  fine  radiating  Striae  which  do  not  terminate  in  spines. 
Short  dental  lamellae  present  along  with  a  more  or  less  high  ventral  median 
septum.  '  Resemble  Spiriferina,  but  the  shell  structure  is  not  finely  and 
regularly  punctate.  Genotype  D.  elevata  Dalman.  Section  Lamellosi-Septaii 
Hall  and  Clarke.     Silurian  and  Devonian ;  distribution  general. 

Subgenus  Uospirifer,  novum.  Quadrate  or  alate  early  Spirifers  that  are 
either  smooth,  radially  undulate,  or  plicate,  but  without  plications  on  fold  and 
sinus.  Surface  with  additional  fine,  filiform,  radiating  Striae  which  may  be 
minutely  crenulate  or  granulöse.  Dental  lamellae  present.  Genotype  Bpirifer 
radiatus  Sowerby.  Section  Radiati  Hall  and  Clarke.  Essentially  Silurian 
but  persisting  into  Lower  Devonian ;  distribution  general. 


412  MOLLUSCOIDEA  phylum  v 


Dalman  (Fig.    623).      Distinguished    from   Spirifer   by   having   an 
unusually  high  ventral  area,  with  its  narrow  delthyrium  closed  by  a  perforated 
pseudodeltidium,   resulting  from  fused  deltidial  plates. 
Silurian  to  Devonian ;  Europe  and  North  America. 

Siibfamily  B,     Reticüläriinae  Waagen. 

Spiriferidae  with  a  spinöse  surface.     Spiralia  prdbahly 
as  in  Triqonotretinae.     Late  Silurian  to  Permian. 


Cyrtia   exporreda  (Walil- 

Naturai  size!"^^ '     °  ^"' "  Beticularia  M'Coy.     Spirifers  without  alations,  and 

generally  without  radial  undulations.  Surface  with 
imbricating  lamellae  that  terminate  in  spines.  Dental  plates  present. 
Genotype  B.  reticulata  M'Coy.  Section  Fimbriati  {pars)  Hall  and  Clarke. 
Devonian  to  Lower  Carboniferous ;  widely  distributed. 

Subgenus  Prosserella  Grabau.     Small  early  Eeticulariae  with  well-developed 
parallel  and  closely  set  dental  lamellae.     Late  Silurian ;  North  America. 

Subgenus  Sguamularia  Gemmellaro.     Like  Beticularia^  but  without  dental 
er  septal  plates.     Carboniferous  and  Permian  ;  widely  distributed. 


Siibfamily  C.     Martiniinae  Waagen. 

Spiriferidae  with  a  smooth  surface.  Spiralia  prohally  as  in  the  Trigonotretinae. 
Devonian  to  Permian. 

Amhocoelia  Hall.  Small,  concave,  or  plano-convex,  usually  smooth  Spirifer- 
like  Shells.  Four  well-defined  adductor  scars  near  the  anterior  margin  in  the 
dorsal  shell.     Devonian  to  Carboniferous  ;  North  America  and  Europe. 

Martinia  M'Coy.  Short-hinged  Spirifers  that  in  general  have  smooth  or 
concentrically  marked  exteriors,  and  rarely  may  be  somewhat  radially  un- 
dulate.  No  dental  plates  or  median  septa.  Genotype  Aiiomites  glaher  Martin. 
Section  Glahrati-Äseptati  Hall  and  Clarke.  Lower  Carboniferous  to  Permian  ; 
distribution  general. 

Subgenus  Martiniopsis  Waagen.  Like  Martinia,  but  with  well-developed 
diverging  dental  and  septal  plates.     Permian  ;  India. 

Subgenus  Mentzelia  Quenstedt.  Like  Martinia,  but  with  a  prominent 
ventral  median  septum.     Triassic ;  Europe. 

Metaplasia  Hall  and  Clarke.  Smooth  Spirifer-\\kQ  shells,  with  a  median 
fold  on  the  ventral  valve  and  a  sinus  on  the  dorsal  valve.  Lower  Devonian ; 
North  America. 

Verneuilia  Hall  and  Clarke.  Small,  smooth  Spirifers,  with  a  deep  median 
sinus  and  two  pronounced  angular  divergent  ridges  on  each  valve.  Devonian 
to  Carboniferous  ;  Europe. 


Family  4.     Suessiidae  Waagen. 

Spiriferacea  with  the  crura  directly  continuous  with  the  hases  of  the  primary 
Spiralia  laterally  directed.     Jugum  continuous  and  more  or  less  V-shaped. 
Shell  structure  highly  punctate.     Silurian  to  Jurassic. 

Cyrtina  Davidson  (Fig.  624).     Cydm-like  shells,  with  the  dental  lamellae 


CLASS  II 


BRACHIOPODA 


413 


converging  and  united  with  the  median  septum.  Silurian  to  Lower  Carboni- 
ferous.     Distribution  general. 

(?)  Cyrtinopsis  Scupin.  Like  Cyrtina,  but  shell  structure  is  not  punctate. 
Devonian ;  Germany. 

Thecocyrtella  Bittner.  Very  small,  ventrally  cemented,  smooth-shelled 
Cyrtinae.     Alpine  Trias.     Cyrtotheca  Bittner.     Alpine  Trias. 

BiUnerula  Hall  and  Clarke.     Like  Thecocyrtella^  but  with  the  abbreviated 


A,  Cyrtina  hcteroclyta(DefT.).    Devonian  ;  Eifel.    i/j.    £,  Shell  with  _ 

dorsal  valv«  mostly  removed,  showing  spiralia,  s/g  (after  Davidson).  *^^'*  ^^^' 

C,  Cyrtina  carhonaria  M'Coy.    Lower  Carboniferous  ;  Kendal,  Ireland.  Spiriferina     rostrata     (Sowerby). 

i/i.    Interior  of  ventral  valve.     The  pseudodeltidium  is  removed  to  Middle    Lias ;    Ilminster.     i/i  (after 

show  the  dental  plates  and  median  septum.  Davidson), 

dental  plates  uniting  with  the  very  high  median  septum,  forming  a  transverse 
platform  beneath  the  united  deltidial  plates.     Alpine  Trias. 

Spiriferina  d'Orb.  (Fig.  625).  Like  Spirifer,  but  with  the  shell  substance 
punctate,  and  a  prominent  ventral  median  septum.  Loop  simple,  complete. 
Carboniferous  to  Jura. 

Suessia  Deslongchamps.  Similar  to  Spiriferina,  but  the  dental  plates  not 
extending  to  the  bottom  of  the  valve.  Jugum  with  a  median  process.  Jura ; 
Europe. 

Family  5.     Uncitidae  Waagen. 

Spiriferacea  with  the  crura  directly  continuous  with  the  bases  of  the  primary 
lamellae.     Spiralia  laterally  directed.     Jugum  as  in  Suessiidae.     Just  within  the 
posterior  margin  of  the  dorsal  valve  are  concave  pouch-like  plates. 
united    and    deeply   concave.      Shell    structure   impunctate, 
Family  anomalous.     Devonian  and  Permian. 

Uncites  Defrance  (Fig.  626).  Shells  rostrate,  striate, 
with  the  ventral  beak  long,  frequently  distorted  and 
arched.  No  cardinal  area.  Deltidial  plates  united, 
forming  a  concave  plate.  Pouch-like  plates  just  within 
the  margins  of  the  dorsal  valve.  Devonian ;  Germany. 
Uncinella  Waagen.     Permian  ;  India. 

Family  6.     Rhynohospiridae  Hall  and  Clarke. 

Derived  Spiriferacea  with  the  bases  of  the  primary 
lamellae  situated  between  the  spiralia  and  sharply  recurved 
dorsally  at  their  junction  with  the  crura.  Spiralia  laterally 
directed. 


Deltidial  plates 


Fio.  626. 


Uncites  gryphus  (Schloth.). 

Jugum    usually   with   a   Single  process   that   is  ?oSf 'i/f"'^''^'   "'*' 


414 


MOLLUSCOIDEA 


PHYLUM  V 


Fig.  027. 


A,  B,  Ptychospira  ferita  (von  Buch).     Devonian ;    Gerolstein,  Eifel.     i/j. 
D,  RhyncJiospira  scdteri  (David.).     Silurian  ;  Wenlock,  Shropshire.     C,  In- 


commonly  recurved,  but  is  sometimes  bifurcated.     Shells  plicate  and  their  structure 
abundantly  punctate.     Silurian  to  Permian. 

Bhynchospira  Hall  (Fig.  627,  C,  D).  Rostrate,  radially  plicate  shells  with 
a   short   curved   hinge-line ;    apex   truncated  by  a   circular   pedicle  opening. 

Dorsal  hinge-plate  like 
that  of  Trematospira. 
Spirals  with  from  six 
to  nine  volutions. 
Jugum  V-shaped,  ex- 
panding  apically  and 
terminating  pos- 
teriorly  in  an  oblique 
edge.  Shell  structure 
punctate.  Devonian 
and  Lower  Carboni- 
ferous;  North  America 

terior  ofdorsa'l  valve.     D,  Median  vertical  section  through  both  valves,  3/^     g^nd  EurODe 
(after  Davidson).  ^   '   . 

Homoeospira  Hall 
and  Clarke.  Like  the  last,  but  dilFers  in  having  a  linear  cardinal  process 
separating  the  crural  plates.  Jugum  not  apically  expanded,  but  terminating 
in  an  acute  stem.     Silurian  ;  North  America. 

Ptychospira  Hall  and  Clarke  (Fig.  627,  A,  B).  Like  Bhynchospira,  but  with 
a  few  angular  plications.  The  jugum  has  a  long,  simple  process  passing 
outward  between  the  coils  to  near  the  inner  surface  of  the  ventral  valve. 
Devonian  to  Lower  Carboniferous ;  North  America  and  Germany. 

Betzia  King  (Trigeria  Bayle).  Resembling  Bhynchospira  externally.  The 
ventral  umbonal  cavity  has  a  split  tube.  The  single  process  of  the  jugum 
terminally  forked.  This  genus  formerly  contained  all  shells  having  a  retzioid 
exterior.  At  present,  however,  but  a  single  species  is  admitted.  Devonian  ; 
Europe.  ^ 

Hustedia  Hall  and  Clarke.  Externally  like  Eumetria, 
but  with  coarse  plications,  and  internally  with  a  split 
tube,  as  in  Betzia.  Spirals  and  jugum  similar  to  those 
of  EuwMria,  but  with  fimbria  and  spinules  respectively. 
Upper  Carboniferous  and  Permian;  America,  Europe, 
India  and  China. 

Trematospira  Hall.  Transverse  Bhynchospirae.  Silu- 
rian and  Devonian ;  North  America. 

ParazygaHsÄlai.ndClsi.Yke  (Fig.  628).  Like  Trematospira, 
but  with  the  fine,  simple  ribs  covered  with  very  delicate, 
short,  hair-like  spines.     Devonian  ;  North  America. 

Eumetria  Hall.  Elongate  terebratuliform  shells  with 
numerous  fine  radiating  Striae.  Hinge  -  line  short. 
Dorsal  hinge-plate  very  complicated.  Jugum  similar 
to  that  of  Betzia,  but  the  terminally  bifurcated  process 
is  extended  back  ward  at  an  abrupt  angle,  and  termi-  Pamzyga  Ursuta  (Haii). 
nates  just  in  front  of  the  apices  of  the  primary  lamellae.  tud?y!^T,  shei°i"me natural 
Shell  structure  punctate.     Lower  Carboniferous;  North    '^"*'-    ^''«^"^e  with  dorsal 


Fig.  628. 


America  and  Europe. 
Acambona  White. 


Carboniferous  :  North  America. 


valve  partly  broken  open, 
shovving  spiralia.  C,  hinge- 
line  of  ventral  valve,  enlarged 
after  Hall). 


BKACHIOPODA 


415 


^^^RiASS  II 

^B  Family  7.     Meristellidae  Hall  and  Clarke. 

Derived  Spiriferacea,  with  the  bases  of  the  primary  lamellae  situated  between  the 
spiralia  and  sharply  recurved  dorsally  at  their  junction  with  the  crura.  Spiralia 
laterally  direded.  The  jugum  has  a  Single  process  that  may  remain  simple  or  may 
bifurcate ;  the  bifurcations,  however,  do  not  enter  between  the  lamellae  of  the  spiralia^ 
but  recurve  and  join  the  jugal  process  near  their  origin.  Shell  usuülly  smooth,  but 
sometimes  finely  hirsute,  and  the  structure  impundate.  Late  Ordovician  to 
Devonian. 

Siibfainily  A.     Hindellinae  Schuchert. 

Primitive  Meristellidae  in  which  the  jugum  has  a  single  process  that  is  usuwUy 
simple  and  rarely  is  sharply  recurved  terminally. 

Hindella  Davidson.  Ovate  or  elongate,  sub-equally  convex,  smooth, 
meristelloid  shells.  The  V-shaped  jugum  has  a  short,  acute  process.  A 
dorsal  median  septum  present.  Late  Ordovician ;  North  America.  Sub- 
genus  Greenfieldia  Grabau.  Has  no  median  dorsal  septum.  Late  Silurian ; 
North  America. 

Whitfieldia  Hall  and  Clarke.  Externally  sometimes  like  Hindella,  but 
usually  the  shells  have  a  fold  and  sinus, 
the  spirals  have  more  volutions,  and  the 
jugal  process  is  longer  and  curved. 
Genotype  W.  nitida  H.  and  C.  Silurian 
and  Lower  Devonian  ;  North  America 
and  Europe. 

Hyattidina,  nom.  nov.  (Hyattella  Hall 
and  Clarke,  non  Fer.  1821).  Similar 
to  Hindella,  but  compactly  sub-penta- 
hedral,  and  without  the  dorsal  median 
septum.  Late  Ordovician  and  early  England 
Silurian  ;  North  America. 

Nucleospira  Hall  (Fig.  629).  Sub-circular,  biconvex  shells  with  numerous 
fine,  short  spinules.  Jugum  with  a  long,  straight,  simple  process.  Silurian 
to  Lower  Carboniferous ;  North  America  and  Europe. 


Fig.  629. 
Nucleospira  pisum  (Sow.).     Silurian  ;  Wenlock, 
Interior  of  dorsal  valve,    B,  Vertical 
section  through  both  valves,  s/g  (after  Davidson). 


Subfamily  B.     Meristellinae  Waagen. 

Specialised  Meristellidae,  in  which  the  jugal  process  bifurcates  and  may  remain 

so  or  may  continue  to  grow,  forming  two  loops  as  in  the  handles  of  scissors. 

Meristina  Hall  {Whitfieldia  Davidson)  (Fig.  630).  Biconvex,  smooth- 
shelled.  Jugal  stem  with  a  short  bifurcation.  Silurian;  North  America 
and  Europe. 

Glassina  Hall  and  Clarke.  Like  Meristina^  but  with  the  bifurcations  of 
the  jugum  originating  directly  from  its  apex.     Silurian ;  England. 

Meristella  Hall.  Externally  like  Merista,  but  without  spondylia.  Apex 
of  jugum  with  two  annular  processes.  Devonian ;  North  and  South  America 
and  Europe. 

MeristoSpira  Grabau.  Like  Meristella,  but  with  strong  dental  lamellae. 
Hinge-plate  perforated  by  a  visceral  foramen  and  the  dorsal  septum  not  united 
with  the  hinge-plate.     Late  Silurian ;  North  America. 


416 


MOLLUSCOIDEA 


PHYLÜM   V 


Charionella  Billings.       Similar  to  the  last,  but  with  a   greatly  modified 
hinge-plate.     Devonian  ;  North  America. 

Pentagonia  Cozzens  (Goniocoelia  Hall).  Meristellids  with  a  broad,  angular, 

Ä  B                                                 G 


Fig.  630. 

Meristina  tumida  (Dalra.).     Silurian  ;  Gotland.     A,  Shell  of  the  natural  size.     B,  Interior  of  ventral  valve. 
C,  Hinge-line  and  median  septum  of  dorsal  valve. 

sharply  limited,  ventral  sinus  and  abrupt  lateral  slopes.  Dorsal  valve  with 
a  wide,  rounded  fold,  divided  by  a  narrow  sinus  and  umbo-laterally  with  two 
short  flanges.     Devonian  ;  North  America. 

Merista  Suess  (Camarium  Hall)  (Fig.   631).     Like  Meristella,  but  with  a 
spondylium.     Silurian  (?)  and  Devonian  ;  Europe  and  North  America. 


Fig.  631. 

Merista  hercuUa  (Barrande).  Devonian  (F-^);  Konieprus,  Bohemia.  A,  External  aspect  of  ventral  valve, 
broken  away  near  the  apex  so  as  to  show  the  "shoe-lifter  jirocess,"  i/i-  B,  Fractured  shcll  showing  median 
septum ;  spiralia  destroyed  (after  Barrande).  C,  D,  Frontal  and  lateral  views  of  spiralia,  slightly  enlarged 
(after  Davidson). 

Dicamara  Hall  and  Clarke.  Meristellids  with  a  spondylium  ("  shoe-lifter 
process  ")  and  brachidium.     Devonian  ;  Europe. 

Dioristella  Bittner.     Similar  to  Meristella.     Alpine  Trias. 

öamarospira  Hall  and  Clarke.  Like  Meristella,  but  with  a  small  spon- 
dylium supported  by  a  median  septum,  to  which  is  attached  only  the  pedicle 
muscle.     Devonian  ;  North  America. 


Family  8.     Ooelospiridae  Hall  and  Clarke. 

Specialised  Spiriferacea,  with  the  primary  lamellae  as  in  the  Meristellidae ;  the 
jugum  has  a  single  process  which  may  remain  simple  and  free,  or  articulate  in  a 
ventral  septal  socket.  Shells  plicate,  often  lamellose,  and  the  structure  impuncfafe. 
Silurian  and  Devonian. 

Änoplotheca  Sandb.  {Bifida  Davidson).     Concavo-convex  small  shells  with 


3S  II 


BRACHIOPODA 


417 


few  plications,  crossed  by  fine,  often  imbricating  growth  lines.  Jugum 
originating  iiear  the  mid-length  of  the  primary  lamellae,  uniting  and  forming 
a  simple  upright  stem  articulating  in  a  cavity  in  the  ventral  valve.  Dorsal 
valve  with  a  high  median  septum.     Devonian ;  Germany  and  France. 

Coelospira  Hall.  Shells  externally  much  like  Atrypina,  but  with  laterally 
directed  spirals.  Jugum  similar  to  that  of  Anoplotheca.  Silurian  and 
Devonian  ;  America  and  Europe.  Subgenus  :  Leptocoelia  Hall.  Larger  shells 
with  coarser  plications.     Silurian  and  Devonian  ;  widely  distributed. 

Anabaia  Clarke.  Similar  to  Coelospira^  but  with  a  highly  convex  dorsal 
valve.     Silurian  ;  Brazil  and  North  America. 

Vitulina  Hall.  Like  Coelospira,  but  with  few  plications  and  a  long 
hinge-line.  Plications  covered  with  fine  radiating  lines  or  rows  of  pustules. 
Devonian  ;  America  and  South  Africa. 


Family  9.     Athyridae  Phillips. 

Specialised  Spiriferacea,  with  the  hases  of  the  primary  lamellae  situated  between 
the  spiralia  and  sharply  recurved  dorsally  at  their  jundion  with  the  crura.  Spiralia 
laterally  directed.  Jugum  complete,  F-shaped,  with  the  apex  drawn  out  into  a  simple 
process  which  hifurcates  ;  this  elongates  and  enters  more  or  less  extensively  between  the 
lamellae  of  the  spiralia.  Shells  smooth,  lamellose^  or  spinöse  ;  structure  impunäate. 
Devonian  to  Triassic. 


Subfamily  A,     Athyrinae  Waagen. 

Primitive  Athyridae,  in  which  the  single  process  of  the  jugum  bifurcates.  The 
branches  usually  terminale  between  the  first  and  second  volutions  of  tJie  spiralia. 
Shells  lamellose  or  spinöse. 

A  li  c 


Fio.  632. 

Athyris  concentrica  (von  Buch).     A,  Shell  with  dorsal  valve  partly  removed. 
i/i.     C,  D,  Frontal  and  lateral  aspect  of  spiralia  (after  Davidson). 


Ji,  Interior  of  dorsal  valve, 


Athyris  M'Coy  (Cleiothyris  Phillips,  7ion  King ;  Spirigera  d'Orb. ;  Euthyris 
Quenstedt)  (Fig.  632). 

Sub-equally  biconvex  shells  with  concentric  growth  lines  extended  into 
lamellae.  Ventral  umbo  not  prominent,  incurved,  usually  concealing  the 
pedicle  opening  and  deltidial  plates.  Teeth  supported  by  dental  lamellae. 
Hinge-plate  of  the  dorsal  valve  perforated  by  a  "visceral  foramen."  The 
peculiar  jugum  of  this  genus  is  illustrated  in  Fig.  632,  C,  D.  Devonian  and 
Carbonif  erous  ;  distribution  general. 

Anathyris  von  Peetz.  Athyrids  with  straight  hinge-lines  and  a  hidden 
ventral  area.     Devonian  ;  Europe. 


VOL.  I 


2  E 


418  MOLLUSCOIDEA  phylum  v 

Actinoconchus  M'Coy.  Athyrids  with  very  wide,  radially  striate,  concentric 
lamellae.     Carboniferous ;  Europe. 

Cleiothyridina  Buckmaii  (Cleiothyris  King,  non  Phillips).  Athyrids  with  con- 
centric rows  of  flat  spinules.  Carboniferous  and  Permian ;  distribution 
general. 

Composita  Bronn  (Seminula  Hall  and  Clarke,  non  M'Coy).  Genotype  Spirifer 
amhiguus  Sowerby.  Smooth-shelled  Athyrids.  Dorsal  hinge-plate  very  pro- 
minent.    Carboniferous ;  distribution  general. 

Comelicania  Frech.  Large,  decidedly  alate  Athyrids  with  arigulated  sinuses 
in  both  valves.     Alpine  Upper  Permian. 

Janiceps  Frech.  Small,  sharply  triangulär  Athyrids  with  angulated  sinuses 
in  both  valves.     Alpine  Upper  Permian. 

Spirigerella  Waagen.     Permian  ;  South  America  and  India. 

Amphitomella  Bittner.  Smoot'h  -  shelied 
Athyrids  with  a  double  cardinal  process  and 
median  septa  in  each  valve.     Alpine  Trias. 

Tetraäinella     Bittner     (Plicigera    Bittner) 
(Fig.  633).      Athyrids  with  four  correspond- 
ing  ribs  on  each  valve.     Alpine  Trias.     Sub- 
genus  :  Stolzenhurgiella  Bittner.     Alpine  Trias. 
^ ,     .   „     .„.„,,,.  X  Pentadinella  Bittner.     Athyrids  with  five 

Tetractmella  tmgoiulla  (ßc\\\ot\\Gim).  ,.  .,  ,  ~  ^ 

Muschelkalk;  Recoaro,  italy..  i/i-        corrcspoudmg  ribs  on  each  valvc.      Uccurs  in 

the  Alpine  Trias. 
Anomactinella  Bittner.     Athyrids  with  a  number  of  angular  alternating 
ribs  towards  the  anterior  margins.     Alpine  Trias. 

Pomatospirella  Bittner.  Small  smooth  shells  having  the  contour  of  Dayia 
or  Cyclospira.     Alpine  Trias. 


Subfamily  B.     Diplospirellinae  Schuchert. 

Specialised  Athyridae  {out  of  the  Athyrinae),  with  the  jugal  bifurcations  very 
long,  lying  hetween  the  volutions  of  the  spiralia,  and  continuing  with  these  to  their 
outer  ends.  Sometimes  there  is  an  additional  jugal  process  which  articulates  with  the 
ventral  valve,  or  recurves  and  joins  the  jugum.     Devonian  to  Triassic. 

Kayseria  Davidson.  Lenticular,  plicated  shells  with  a  median  plicated 
sinus  on  both  valves.  Jugum  with  a  ventral  articulating  process  and  the 
bifurcations  continued  between  the  spiral  ribbons  to  their  outer  ends. 
Devonian ;  Germany.  * 

Diplospirella  Bittner.  Athyrids  with  the  jugal  processes  coextensive 
with  the  principal  spiral  coils.     Alpine  Trias. 

Pexidella  Bittner.  Athyrids  difFering  from  Diplospirella  in  that  the 
jugum  is  much  reduced  and  situatedj^in  the  umbonal  region.  Valves  much 
thickened  in  the  apical  region.     Alpine  Trias. 

Euractinella  Bittner.  Diplospirellids  with  short  corresponding  ribs. 
Alpine  Trias.     Didymospira.     Salomon.     Alpine  Trias. 

Anisactinella  Bittner.  Diplospirellids  with  alternating  ribs,  The 
secondary  spiral  coils  give  off  a  process  which  returns  and  joins  the  jugum. 
Alpine  Trias. 


I  CLÄSS  II 

m 


BKACHIOPODA 


419 


Su1)family  C.     Koninckininae  Waagen. 

Highly  specialised  Athyridae  with  jugum  and  spiralia  essentially  as  in  Diplo- 
spirellinae.  The  spiralia,  however,  are  not  laterally  direäed  as  in  the  former  group, 
hut  point  ventrally,  this  being  due  to  the  concave  form  of  the  dorsal  valve.  Triassic 
and  Jurassic. 

KonimUna  Suess  (Fig.  634).  Shell  sub-orbicula^r,  concavo-convex,  smooth, 
with  a  straight  hirige-line,  or  strophomenoid  in  external  appearance.  Car- 
dinal  area  obsolete  at  maturity.     The   accessory   spirals   take  their  origin 


Fig.-  634. 

Koninckiiia  leonhardi  (Wissm.).  Upper 
T*rias  ;  St.  Cassian,  Tyrol.  A,  Shell  show- 
ing  spiralia,  enlarged.  B,  Ventral  and 
dorsal  aspects,  Vi- 


Fig.  635. 

AmpMclinafVfith  re- 
stored  brachidia  (after 
Bittner). 


Fig.  636. 

Thecospira  haiditigeri  (Suess). 
Rhaetic ;  Starhemberg,  Austria. 
A,  Ventral  valve,  Vi-  B,  C, 
Brachidia,  enlarged  (after  Zug- 
meyer). ' 


from  the  upper  surface  of  the  jugum,  and  are  coextensive  with  the  primary 
spirals.     Trias ;  Europe. 

Amphidina  Laube  (Fig.  635).  Like  Koninckina,  but  sub-trigonal  in  out- 
line, and  with  well-developed  cardinal  area  and  deltidial  plates.  Trias  and 
Jura ;  Europe. 

Koninckella  Munier -Chalmas.  Similar  to  Amphidina,  but  with  well- 
developed  cardinal  process.     Trias  and  Jura ;  Europe. 

Amphidinodonta  Bittner.  Like  Amphidina,  but  with  interlocking  denti- 
culate  ridges  and  tubercles  within  the  margins  of  the  valves.     Alpine  Trias. 

Koninckodonta  Bittner.  Like  Koninckina,  but  with  prominent  cardinal 
areas  and  a  row  of  sub-marginal  thickened  tubercles  on  the  interior  of  the 
ventral  valve,  which  interlock  with  similar  callosities  on  the  dorsal  valve. 
Alpine  Trias. 

Thecospira  Zugmeyer  (Fig.  636).  Ventrally  cemented  Koninckininae  with 
well-developed  cardinal  area  and  cardinal  process.     Alpine  Trias. 

Range  and  Distribution  of  the  Braohiopoda. 

Owing  to  their  great  abundance,  world-wide  distribution  and  remote 
antiquity,  as  well  as  their  excellent  state  of  preservation,  Brachiopods  occupy 
a  very  conspicuous  rank  among  extinct  Invertebrates,  and  furnish  us  besides 
with  a  large  number  of  important  stratigraphic  index  fossils.  The  composi- 
tion  of  their  shells,  usually  of  calcite,  enables  them  to  resist  the  destructive 
action  of  the  fossilisation  process  more  successfully  than  the  shells  of  Mollusks, 
many  of  which  are  composed  wholly  or  in  part  of  aragonite.  Their  value 
as  index  fossils,  however,  is  somewhat  lessened  owing  to  the  difficulty  of 
identifying  numerous  genera,  without  a  knowledge  of  their  internal  structure, 
and  this  is  often  difficult  to  ascertain. 


420  MOLLUSCOIDEA  phylum  v 

Three  of  the  four  Orders  into  which  the  class  is  divided  are  represented  in 
the  lowest  Cambrian,  or  Olenellus  zone,  indicating  that  Brachiopods  had  their 
origin  in  pre-Cambrian  times.  In  the  Lower  and  Middle  Cambrian,  the 
Atremata  and  Neotremata  predominate ;  and  although  the  Protremata  are  known 
in  the  Lower  Cambrian  by  very  typical  species,  it  is  not  until  the  Upper 
Cambrian  that  the  order  becomes  conspicuous.  They  are  particularly  char- 
acteristic  of  the  Paleozoic.  The  Telotremata  do  not  appear  until  the  Middle 
Ordovician  and  since  Silurian  times  have  always  been  prolific,  but  are 
especially  characteristic  since  early  Mesozoic  times. 

In  the  Lower  Cambrian  (Olenellus  beds),  22  genera  of  Brachiopods  are 
represented,  occurring  both  in  North  America  and  in  Europe.  A  marked 
increase  is  apparent  in  the  Middle  Cambrian,  for  here  Walcott  records  37 
genera,  and  in  the  Ordovician  and  Silurian,  where  the  climax  of  their  diversity 
is  reached,  upwards  of  3000  species  are  known.  These  are  distributed  chiefly 
in  North  America  and  in  Europe  (Great  Britain,  Scandinavia,  Bohemia, 
Russia  and  Portugal) ;  but  numerous  forms  are  also  found  in  South  America, 
Australia,  China  and  eastern  Siberia. 

In  the  Devonian,  Brachiopods  are  scarcely  less  plentiful  than  in  the  Silurian, 
although  a  considerable  number  of  genera,  especially  those  belonging  to  the 
Atremata  and  Neotremata,  have  now  disappeared.  The  most  noted  European 
localities  where  Brachiopods  abound  are  the  Eifel,  Rhineland,  Westphalia,  the 
Hartz,  Belgium,  Devonshire,  Boulogne-sur-Mer,  Cabrieres  in  the  Cevennes, 
the  Asturias  and  the  Urals.  North  America  also  yields  great  quantities  of 
Devonian  Brachiopods. 

The  Carboniferous  of  North  America  and  its  equivalent  horizons  in  Europe 
and  Eastern  Asia,  together  with  the  Permian  of  the  Mediterranean  countries, 
India  and  Armenia,  are  very  rieh  in  Brachiopod  remains,  especially  those 
belonging  to  the  Produdidae,  Strophomenidae,  Spiriferidae  and  Rhynclionellidae. 

In  the  North  European  Permian,  the  number  of  species  of  Brachiopods  is 
reduced  to  about  30,  but  in  the  Salt  Range  of  India  far  greater  numbers 
occur.  In  the  Alpine  Trias,  the  Terehratulidae,  Rhynchonellidae  and  Koninck- 
ininae  attain  a  great  development. 

The  Jurassic  and  Cretaceous  Brachiopods  belong  almost  exclusively  to 
the  Terehratulidae,  Rhynchonellidae  and  Thecidiidae ;  the  first  two  families  in 
particular  being  represented  by  an  astonishing  number  of  species.  The 
Spiriferacea  become  extinct  in  the  Lias. 

With  the  beginning  of  the  Cenozoic  era,  Brachiopods  are  no  longer  a  con- 
spicuous group  of  fossils.  The  species  occurring  in  the  Tertiary  are  almost 
without  exception  generically  identical  with  those  now  living,  and  scarcely 
exceed  them  in  number.  On  this  account  they  are  devoid  of  practical  interest 
or  importance  to  the  geologist. 


Phylum  VI.    MOLLUSCA.' 

(Malacozoa  Blainville ;  Saccata  Hyatt.) 

The  Mollusca  form  a  well-characterised,  and,  on  the  whole,  remarkably 
homogeneous  group  of  Invertebrates,  which  have  existed  since  the  earliest 
recognised  advent  of  life  upon  the  globe.  Their  progressive  modifications 
afFord  us  a  most  important  guide  to  the  successive  stages  of  the  evolution  of 
organic  life  as  preserved  in  the  various  geological  horizons. 

The  Mollusca  are  characterised  as  a  group  by  passing  through  a  Trocho- 

^  Literature  :  Adams,  H.  and  A.,  The  Genera  of  Recent  Mollusca,  2  voLs.  London,  1853-58. — 
Philippi,  R.  A.,  Handbuch  der  Conchyliologie,  Halle,  1853. — Keferstein,  W.,  Die  Malacozoa. 
Bronn's  Classen  und  Ordnungen  des  Thierreichs,  vol.  iii.,  1862-66. — Tryon,  O.  W.,  and  Pilsbry, 
H.  A.,  Manual  of  Conchology,  16  vols.  Philadelphia,  1879-96. — Fischer,  P.,  Manuel  de  Con- 
chyliologie et  de  Paleontologie  conchyliologique,  1880-87. —  Woodward,  S.  P.,  Manual  of  the 
Mollusca.  4th  Edition,  with  Appendix  by  R.  Täte,  1880. — Tryon,  G.  W.,  Stnictural  and  Syste- 
matic  Conchology,  3  vols.  Philadelphia,  1882-84. — Ihering,  H.  von,  Le  Systeme  naturel  des 
Mollusques.  Bull.  Sei.  France,  1891,  vol.  xxiii. — Pelseneer,  P.,  Introduction  ä  l'etude  des 
Mollusques.     Brüssels,  1894. 

Soioerhy,  J.,  Mineral  Conchology  of  Great  Britain,  7  vols.  London,  1812-30. — Brocchi,  G.  B., 
Conchiologia  fossile  subappenina,  2  vols.  Milan,  1814. — Deshayes,  G.  P.,  Coquilles  fossiles  des 
environs  de  Paris,  3  vols.,  1824-37. — Goldfuss,  A.,  Petrefacta  Germaniae,  1826-40. — Conrad,  T.  A., 
Fossil  Shells  of  the  Tertiary  Formations  of  North  America  (1832-33)  ;  and  Fossils  of  the  Medial 
Tertiary  of  the  United  States  (1838-61).  Reprints  by  G.  D.  Harris,  \^^Z.— Morton,  S.  G.,  Synopsis 
of  the  Organic  Remains  of  the  Cretaceous  Group  of  the  United  States,  1834. — Philippi,  R.  A., 
Enumeratio  Molluscorum  Siciliae,  2  vols.,  l^^Q-ü.—Grateloup,  J.  P.  S.,  Catalogue  zoologique  du 
Bassin  de  Gironde.  Bordeaux,  1838-40. — Hall,  J.,  Palaeontology  of  New  York,  vols.  i.-viii. 
Albany,  1847-95.  —  Wood,  S.,  Monograph  of  the  Crag  Mollusca.  Palaeont.  Soc,  1848-56,  vols.  1., 
ii.^ — Sandherger,  G.  and  F.,  Die  Versteinerungen  des  rheinischen  Schichtensystems  in  Nassau, 
1850-56. — Morris  and  Lycett,  Monograph  of  the  Mollusca  of  the  Great  Oolite.  Palaeont.  Soc, 
1850-63. — M^Coy,  F.,  British  Palaeozoic  Fossils.  London,  1851-55. — Pictet,  F.  J.,  and  Campiche, 
G.,  Description  des  fossiles  du  terrain  cretace  de  Sainte-Croix.  Paleont.  Suisse,  ser.  5,  vols.  i.-iv., 
1858-72. — Quenstedt,  F.  A.,  Der  Jura.  Tübingen,  1858. — Sandherger,  F.,  Die  Conchylien  des 
Mainzer  Beckens.  Wiesbaden,  1860-63. — Deshayes,  G.  P.,  Description  des  animaux  sans  vertebres 
decouverts  dans  le  Bassin  de  Paris,  5  vols.  Paris,  1860-66. — Loriol,  P.  de,  Monographs  of  the 
Fauna  of  the  Upper  Jura  of  Switzerland,  Haute-Marne,  Yonne,  Boulogne-sur-Mer,  Valßn,  Tonnerre  ; 
of  the  Neocomian  of  Mt.  Saleve  ;  the  Urgonian  of  Landeron  ;  the  Gault  of  Cosne,  etc.,  1861-75. — 
Cossmann,  M.,  Essais  de  paleoconchologie  comparee.  Paris,  1895. — Gabb,  W.  M.,  Palaeontology  of 
California,  vols.  i.  and  ii.,  1864,  1869.— Idem,  Topography  and  Geology  of  Santo  Domingo.  Trans. 
Am.  Phil.  Soc,  1873,  vol.  xv.—  Geinitz,  IL  B.,  Die  Dyas.  Leipzic,  1864. — Ktminck,  L.  G.  de, 
Faune  du  calcaire  carbonifere  de  la  Belgique.  Ann.  Mus.  d'Hist.  Nat.  Belg.,  1886,  vol.  vi. — M'Coy, 
F.,  Synopsis  of  the  Characters  of  the  Carboniferous  Limestone  Fossils  of  Ireland,  1862. — Meek, 
F.  JB.,  Report  on  the  Invertebrate  Cretaceous  and  Tertiary  Fossils  of  the  Upper  Missouri  Country. 
U.S.  Geol.  Surv.  Terr.,  1876,  vol.  ix.  —  Waagen,  W.,  Salt  Range  Fossils.  Mem.  Geol.  Surv.  India. 
Palaeont.  Indica,  ser.  13,  \880-9>7 .  —  White,  C.  A.,  Non-marine  fossil  Mollusca  of  North  America. 
3rd  Ann.  Rept.  U.S.  Geol.  Survey,  1883.— Walcott,  C.  D.,  Fauna  of  the  Lower  Cambriau  or 
Olenellus  Zone  lOth  Ann.  Rept.  U.S.  Geol.  Surv.,  1890.  — Whidhorne,  G.  F.,  Monograph  of  the 
Devonian  Fauna  of  the  South  of  England.  Palaeontogr.  Soc,  1889-1907.— J/ee^,  F.  B.,  and 
Worthen,  A.  H.,  Palaeontology  of  Illinois,  1866-75,  vols.  i.-vi. 

421 


422  MOLLUSCA  phylum  vi 

sphere  and  a  Veliger  larval  stage ;  by  possessing  bilaterally  symmetrical, 
unsegmented  bodies ;  a  larval  shell  gland,  from  which  a  Härder  exoskeleton 
or  shell  is  secreted,  though  not  always  permanently  retained ;  a  mouth, 
intestinal  canal  and  anus ;  a  closed,  but  partly  lacunary  circulation,  assisted 
by  a  heart  with  one  or  more  auricles,  and  containing  a  usually  colourless 
body  fluid  or  haemolymph ;  a  nervous  System  with  at  least  three  pairs  of 
ganglia  connected  by  commissures ;  sexual  reproduction  by  ova  and  sper- 
matozoa  ;  audition  and  equilibration  provided  for  by  otocysts ;  respiration 
by  ctenidial  or  secondary  gills,  or  by  the  tegumentary  surface,  which  may  be 
invaginated  to  form  a  pulmonary  sac ;  locomotion  by  a  muscular  organ  called 
the  foot,  or  by  special  parapodial  structures,  or  by  swimming;  the  organs 
typically  paired,  and  protected  by  a  sac-like  integument  called  the  mantle ; 
and  the  visceral  sac  having  a  tendency  toward  torsion,  so  as  to  become  usually 
asymmetrical.  Sexually  Mollusks  are  usually  dioecious ;  or,  if  monoecious, 
are  incapable  of  self-fertilisation. 

Owing  to  the  homogeneity  of  the  group,  its  division  into  classes  has  been 
attended  with  some  differences  of  opinion,  depending  upon  the  point  of  view, 
the  anatomist  laying  more  stress  upon  certain  groups  of  characters,  and  the 
morphologist  upon  others.  From  a  general  Standpoint,  the  Mollusca  are 
readily  divisible  into  five  classes,  as  follows :  Pelecypods,  Scaphopods, 
Amphineura,  Gastropods  and  Cephalopods.  The  first  of  these  is  well  marked 
ofF  from  the  rest  by  the  presence  of  a  bivalved  shell  and  the  absence  of  a 
distinct  head  and  of  a  radula,  and  the  two  groups  have  been  contrasted  as 
Aglossa  (or  Lipocephala)  and  Glossophora  (or  Cephalophora). 


'    Olassl.    PELECYPODA  Goldfuss.^ 

(Lamellibranchiata  Blainville  ;  Conchifera  Lamarck ;  Bimlvia  (Bonanni)  Linn6  ; 

Lipocephala  Lankester.) 

Aquatic,   bilaterally  symmetrical,  acephalous  Mollusks,  protected  hy  a  pair  of 
shelly  valves,  which  are  secreted  by  the  lateral  portions  of  the  mantle,  connected  by  an 

1  Literature :  Neumayr,  M.,  Zur  Morphologie  des  Bivalvenschlosses.  Sitzungsber.  Akad. 
Wiss.  Wien,  1883,  vol.  Ixxxiii,,  and  Denkschr.  1891,  vol.  Iviii,— üeber  die  Herkunft  der  Unioniden. 
Sitzungsber.  Akad.  Wiss.  1889,  vol.  xcviii. — Beiträge  zu  einer  morphologischen  Eintheihmg  der 
Bivalven  ;  mit  Vorwort  von  E.  Suess.  Denkschr.  Akad.  Wiss.  Wien,  1891,  vol.  Iviii.  —  White, 
CA.,  Review  of  the  fossil  Ostreidae  of  North  America,  4th  Ann.  Report  U.S.  Geol.  Survey 
(1883),  1S8A.— Jackson,  R.  T.,  Phylogeny  of  the  Pelecypoda.  The  Aviculidae  and  their  Allies. 
Mem.  Boston  Soc.  Nat.  Hist.,  1890,  vol.  iv.  no.  8. — Minegaux,  A.,  Recherches  sur  la  circulation 
des  Lamellibranches  marines,  1890. — Hyatt,  A.,  Remarks  on  the  Pinnidae,  Proc.  Boston  Soc. 
Nat.  Hist.,  1892,  vol.  xxv. — Moynier  de  Vülepoix,  R.,  Recherches  sur  la  formation  et  l'accroisse- 
ment  de  la  coquille  des  mollusques,  1893.— ^erwar^,  F.,  Serie  de  notes  sur  le  developpement  et  la 
'morphologie  de  la  coquille  chez  les  Lamellibranches.  Bull.  Soc.  Geol.  France  [3],  1895-97,  vols. 
xxiii. -XXV.— Dali,  W.  ff.,  Anew  Classification  of  the  Pelecypoda.  Trans.  Wagner  Inst.  Sei.  Phila- 
delphia, 1895,  vol.  iii.  pt.  3.  Also  Proc.  U.S.  Nat.  Mus.,  1895,  vol.  xvii.  no.  1Q^2.— Hyatt,  A. 
Terminology  proposed  for  the  Description  of  the  Shell  in  Pelecypoda.  Proc.  Am.  Assoc.  Adv. 
Sei.,  1895,  vol.  xliv.— Fischer,  ff.,  Resume  des  travaux  de  M.  F.  .Bernard  sur  le  developpement 
de  la  coquille  des  Pelecypodes.  Journ.  de  Conch.,  1897,  vol.  xlv.,  no.  A.—March,  M.  C,  General 
Classification  of  the  Pelecypoda.     Ann.  Mag.  Nat.  Hist.,  [8]  1912,  vol.  x. 

A.  On  Paleozoic  Forms  :  Barrande,  J.,  Systeme  Silurien  du  centre  de  la  Boheme.  Acephales, 
i.-iv.,  1882.— ßee«ie,  /.  W.,  Carboniferous  Invertebrates.  Kansas  Univ.  Geol.  Surv.,  1900,  vol.  vi. 
—Clarke  J.  M.,  Naples  Fauna  in  western  New  York.  Mem.  N.Y.  State  Mus.,  vi.,  1900.— //aZ^,  J., 
Geol.  Surv.  New  York.  Palaeont.,  vol.  v.,  1884-85.— /rZew,  Whitfield,  R.  P.,  Meek,  F.  B.,  and 
Ulrich,  E.  0.,  Description  of  Palaeozoic  Fossils.  Palaeont.  Ohio,  1873-75,  vols.  i.,  ii.,  and  Geol. 
Ohio,   1893,   vol.  \\\.~ffind,    W.,   Monograph  of  the  British   Carboniferous    Lamellibranchiata. 


CLASS  I  PELECYPODA  423 

elastic  Wjament,  and  closed  hy  the  contradion  of  musdes  attadied  to  the  inner  faces  of 
the  valves  ;  feeding  hy  ciliary  adion  and  destitute  of  a  radula  or  jaw  ;  breathing  hy 
lateral  gills  ;  im'perfedly  sensible  to  light  and  rarely  provided  with  peripheral  Visual 
Organs  ;  possessing  olfadory  organs  (osphradia)^  auditory  and  equilibrating  organs 
(otocysts),  tadile  papillae,  and  a  nervous  system  composed  of  ganglia  united  hy  nerves^ 
but  without  a  pedovisceral  commissure ;  provided  with  an  extensile,  tadile  or  loco- 
motor  organ  (foot) ;  a  circulatory  system  containing  haemolymph,  and  operated  hy  a 
Single  or  paired  cardial  ventricle  and  two  aurides  ;  a  more  or  less  convoluted  intestinal 
ca7ial,  with  its  oral  and  anal  extremities  at  opposite  ends  of  the  hody  ;  a  stomach  ; 
paired  nephridia,  conneded  with  the  pericardium,  and  discharging  independently  of 
the  redum  ;  reproducing  without  copulation,  hy  ova  and  spermatozoa  ;  monoecious  or 
dioecious ;  development  external  to  the  ovary ;  the  post-larval  stage  proteded  hy  a 
prodissoconch,  and  sometimes  exhihiting  special  nepionic  stages. 

External  Charaoters.     The  Shell. — The  embryonic  Pelecypod  is  provided 

Palaeoiit,  Soc,  1896-1905. — Ulrich,  E.  0.,  Lower  Silurian  Lauiellibranchiata  of  Minnesota.  Rept. 
Geol.  Surv.  Minn.,  1897,  vol.  iii. 

B.  On  Mesozoic  Forms  :  Benecke,  E.  W.,  Die  Versteinerungen  der  Eisenerzformation  von 
Deutsch  -  Lothringen  und  Luxemburg.  Abh.  Geol.  Spezialkarte  Elsass  -  Lothring.,  1905,  n.s., 
vol.  V. — Bittner,  A.,  Revision  der  Lamellibranchiaten  von  St.  Cassian,  Abh.  Geol.  Reichsanst. 
Wien,  1895,  vol.  xviii. — Böhm,  O.,  Die  Bivalven  der  Stramberger  Schichten.  Paläont.  Mittheil. 
Mus.  Bayer.  Staates,  1883,  vol.  ii. — Borrissyak,  A.,  Die  Pelecypoden  der  Jura- Ablagerungen  im 
europaischen  Russland.  Mem.  du  cours  geol.,  nouv.  ser.,  1904-9. — Broili,  F.,  Die  Fauna  der 
Pachycardientuffe  der  Seiser  Alp.  Palaeontogr.,  1903-7,  vols.  1.,  liv. — Coquand,  W.,  Monographie 
du  genre  Ostrea  des  terrains  cretaces,  1869. — Healey,  31.,  The  Fauna  of  the  Napening  beds 
(Rhaetic)  of  Upper  Burma.  Palaeont.  Indica,  1908,  n.s.,  vol.  ii.,  no.  4. — Holzapfel,  E.,  Die 
Mollusken  der  Aachener  Kreide.  Palaeontogr.,  1887,  vol.  xxxiv. — Kitchin,  F.  L.,  The  Jurassic 
Fauna  of  Cutch.  Lamellibranchiata.  Palaeont.  Indica,  1903,  ser.  ix.,  vol.  iii.,  pt.  2. — Lavhe,  O., 
Die  Fauna  von  St.  Cassian.  Denkschr.  Akad.  Wiss.  Wien,  1866,  vol.  xxv. — Pavloto,  A.,  Enchaine- 
ments  des  Aucelles  et  Aucellines  du  Cretace  Russe.  Nouv.  Mem.  Soc.  Imper.  Nat.  Moscou,  1009, 
vol.  xvii. — Pompeckj,  J.  F.,  Über  Aucellen  und  Aucellen  -  ähnliche  Formen.  Neues  Jahrb.  f. 
Min.,  1901,  Supplem.  vol.  xiv. — Qiiaas,  A.,  Beitrag  zur  Kenntniss  der  Fauna  der  obersten 
Kreidebildung  in  der  Lybischen  Wüste.  Palaeontogr.,  1902,  vol.  xxx.  pt.  2 — Stoliczka,  F., 
Cretaceous  Fauna  of  Southern  India!  The  Pelecypoda.  Mem.  Geol.  Surv.  East  India,  1871,  vol. 
iii. — Waagen,  L.,  Die  Lamellibranchiaten  der  Pachycardientuffe  der  Seiser  Alp.  Abh.  Geol. 
Reichsaust.  Wien,  1907,  vol.  xviii.  pt.  2.  —  Wood,  H.,  Monograph  of  the  Cretaceous  Lamelli- 
branchiata of  England.  Palaeont.  Soc,  1899,  vol.  \m.~Zittel,  K.  A.  von,  Die  Bivalven  der 
Gosaugebilde.      Denkschr.  Akad.  Wiss.  Wien,  1865-66,  vol.  xxv. 

C.  On  Tertiary  Forms  :  Androussov,  JV.,  Fossile  und  lebende  Dreissensidae  Eurasiens.  Trav. 
Soc.  Imp.  Sei.  Nat.  St-Petersb.,  sect.  geol.,  1897,  1903,  vols.  xx.,  xxix. — Arnold,  R.,  The 
Tertiary  and  Quaternary  Pectens  of  California.  U.S.  Geol.  Surv.  Profess.  Papers,  no.  47,  1906. — 
Bellardi,  L.,  and  Sacco,  F.,  1  Molluschi  terziari  del  Piemonte  e  della  Liguria.  Torino,  1872-1901. — 
Cossvumn,  M. ,  Catalogue  illustre  des  coquilles  fossiles  de  l'Eocene  des  environs  de  Paris.  Fase. 
Ann.  Soc.  Malacol.  de  Belgique,  1888-89,  vols,  xxiii.,  xxiv.—Idem,  and  Pissaro, ^  G.,  Iconographie 
complete  des  coquilles  fossiles  de  l'^^ocene  des  environs  de  Paris.  Fase.  1,  Pelecypodes,  1904. — 
Dali,  W.  H.,  Contributions  to  the  Tertiary  Fauna  of  Florida,  i.-vi.  Trans.  Wagner  Inst.  Sei., 
1890-1903,  vol.  in.— Deperet,  G.,  and  Roman,  F.,  Monographie  des  Pectinides  neogenesde  l'Europe 
et  des  regions  voisiues.  Mem.  Soc.  Geol.  France,  1902,  vol.  x. — Fontannes,  F.,  Les  Mollusques 
pliocenes  de  la  Vallee  de  Rhone  et  du  Roussillon.  Lyons,  1879-83.— G^regrorto,  A.,  Monographie 
de  la  faune  eoci'nique  de  l'Alabama.  Palermo,  1890.  — Ä^ams,  G.  D.,  Bull.  Amer.  Palaeont.,- 
1895-97,  vols.  i.-iv. — Hoernes,  M.,  Die  fossilen  Mollusken  des  Tertiärbeckens  von  Wien.  Abhandl. 
Geol.  Reichsanst.  Wien,  1870,  vol.  iv.—Koenen,  A.  von.  Das  norddeutsche  Unter-Oligocän  und 
seine  Mollusken-Fauna.  Abhandl.  Geol.  Spezialkarte  Preussen,  1889-93,  vol.  x.—Oppen}wim, 
P.,  Zur  Kenntnis  alttertiärer  Faunen  in  Ägypten.  Palaeontogr.,  1903-6,  vol.  xxx.  pt.  3. — 
Ortmann,  A.  E.,  Families  and  Genera  of  the  Najades.  Ann.  Carnegie  Mus.,  1912,  vol.  viii.  no. 
x.  — Sandherger,  F.,  Die  ■  Conchylien  des  Mainzer  Beckens,  1860-63.— /rfm.  Die  Land-  und 
Siisswasser  -  Conchylien  der  Vorwelt.  Wiesbaden,  \9>n.  —  Schaff  er,  F.  X.,  Die  Bivalven  der 
Miocänbildungen  von  Eggenburg.  Abh.  Geol.  Reichsanst.  Wien,  1910,  vol.  xxW.— Simpson,  C.  J., 
Synopsis  of  the  Naiades  or  Pearly  Fresh-water  Musseis.  Proc.  U.S.  Nat.  Mus.,  1900,  vol.  xxii.,  no. 
1205.  — Ugolini,  R.,  Monografia  dei  Pettinidi  neogenici  della  Sardegna.  Palaeont.  Ital.  1906-7, 
vols.  xii.,  xnl— Wood,  S.,  Monograph  of  the  Eocene  Bivalves  of  England.  Palaeontogr.  Soc, 
1861-71. 


424 


MOLLUSCA 


PHYLÜM  VI 


with  a  saddle-shaped,  single  shell  gland,  which  secretes  a  pellicle  of  the  same 
form,  lipon  which,  at  two  points  corresponding  to  the  valves,  calcification  sets 
j  j^  in    independently.       These   rudiments    remain    con- 

nected across  the  dorsum  for  a  time,  by  the  uncal- 
cified  portion  of  the  original  pellicle,  which  develops 
into  the  ligament  of  the  adult.  The  paired  em- 
bryonic  shell,  corresponding  to  the  protoconch  of 
Cephalopods,  has  been  named  by  Jackson  the  pro- 
dissoconch  (Figs.  637,  638).  In  general  these  valves 
are  very  uniform  in  character,  as  seen  on  the  tips 
Compieted  of  the  uneroded  valves  in  the  adult.  They  are 
usually  rounded  or  slightly  pointed  at  the  umbonal 


Fio.  637. 


Ostrea  virginiana 
prodissocouch  stage,  viewed  from 
the  anterior    end  (A),  and    from 
the    right   upper    aide    (B). 
(after  Jackson). 


**^/i  end,  and  have  in  their  earliest  stages  a  straight, 
rather  long  hinge  line.  In  Solemya  the  prodissoconch 
is  elongate,  rounded  at  the  ends,  with  the  ventral  and  dorsal  margins  nearly 
parallel,  much  as  in  the  adult  shell.  In  Pinna  the  prodissoconch  is  globular, 
as  in  most  bivalves.     In   Z7mo,  Anodon  and  Philohrya,  a  second  or  nepionic 


Fig.  038. 

A,  Avicula  sterna.  Young  specinien,  viewed  from  tlie  left  (a)  and  right  (b)  sides,  the  latter  showing  byssal 
sinus.  i9/i.  B,  Area  pexata.  Very  young,  showing  prodissoconch  (2>),  succeeded  by  early  dissoconch  growth. 
"i^/i  (after  Jackson), 

stage  is  traceable,  owing  to  a  semi-parasitic  habit  of  the  young,  which  leave 
the  mother  and  become  encysted  on  the  fins  or  gills  of  fishes ;  during  this 
period  the  shell  remains  stationary,  though  some  development  of  the  contained 
soft  parts  is  in  progress. 

The  bivalve  shell  reduced  to  its  lowest  terms  comprises  two  convex  pieces 
(the  valves),  attached  to  one  another  dorsally  (1)  by  an  elastic  ligament  usually 
external  to  the  cavity  of  the  two  valves;  and  (2)  by  muscles  and  connective 
tissues  which  pass  from  the  inner  surface  of  one  valve  to  the  inner  surface  of 
the  opposite  valve.  The  contraction  of  the  muscles  brings  the  margins  of  the 
valves  into  close  contact,  thereby  forming  a  hollow  receptacle  in  which  the 
soft  parts  of  the  animal  are  enclosed,  and  from  which  all  obnoxious  foreign 
matters  may  be  excluded.  The  elasticity  of  the  ligament,  acting  on  the 
principle  of  the  C-spring,  tends  to  separate  the  valves  when  the  tension  of 
the  internal  adductor  muscles  is  relaxed.  The  extension  of  the  substance 
of  the  valve  is  secreted  by  marginal  glands  around  the  edge  of  the  investing 
tissue  or  mantle,  and  is  subsequently  reinforced  by  material  supplied  by 
secretion  from  the  general  surface  of  the  mantle.  As  the  animal  grows  and 
the  original  prodissoconch  becomes  too  small  to  cover  the  soft  parts,  the  valves 
are  enlarged  around  the  margins,  so  that  each  of  them  represents,  fundament- 
ally,  a  hollow  cone.  Since  growth  progresses  more  rapidly  along  some 
portions  of  the  mantle  than  at  others,  the  cones  necessarily  become  oblique, 


CLÄSS  I  PELECYPODA  425 

arched  or  cycloidally  curved.  The  apex  of  the  cone  is  formed  by  the  beak 
or  umho  of  the  valve,  the  base  is  the  entire  margin  of  the  valve. 

The  shell  of  most  Pelecypods  is  composed  of  several  layers  of  distinct 
structure.  The  external  layer  is  usually  thin,  flexible  and  dark-coloured, 
chiefly  composed  of  a  horny  substance  termed  conchiolin.  This  layer  is 
known  as  the  epidermis,  or  more  properly  the  periostracum ;  it  is  not  easily 
corroded,  and  hence  serves  as  a  protection  to  the  underlying  calcareous 
layers.  The  outer  calcareous  layer  is  composed  of  prisms  of  calcite  arranged 
more  or  less  perpendicular  to  the  external  surface ;  the  inner  layer  is  made 
up  of  thin,  more  or  less  parallel  lamellae  of  porcellanous  or  pearly  texture, 
disposed  at  right  angles  to  the  general  direction  of  the  prismatic  layer, 
and  exhibiting  the  mineralogical  characters  of  aragonite  (Fig.  639).  Besides 
the  lamellar  or  prismatic 
structure,  many  forms  show 
under  the  microscope 
minute,  sometimesbranched 
tubulation. 

The  variations  in  shell 
substance  are  somewhat 
characteristic  of  diff'erent 
groups.     The  prisms  difFer  p^^.  239 

greatly    in    size,    the    larger  Vertical  section  of  the  shell  of  Unio.    e,  b,  a,  a',  the  oiiter  pris- 

nppnrriTirr  in    hinnm-nmiiQ  ':^n(\     «latic  layer,  showing  successive  increments  of  shell  growth  ;   c,  c', 
OCCUrring  m  inoceramus  ana    ^.j^^  1^^^^  lamellar  strata.     Highly  magnified  (after  Carpenter). 

Pinna,   the  smaller  in   the 

Anatinidae  and  Myacidae.  The  prismatic  layer  is  wholly  absent  in  the 
Chamidae  and  many  other  Teleodesmacea ;  in  the  Pectinidae  and  Limidae 
the  prismatic  layer  is  feebly  developed  and  often  recognisable  only  in  young 
Shells.  In  the  Rudistae  the  prisms  run  nearly  parallel  with  the  outer  surface. 
As  aragonite  is  more  soluble  than  calcite,  it  frequently  happens  in  fossil 
Shells  that  the  layers  composed  of  the  former  mineral  have  entirely  dis- 
appeared,  leaving  only  the  calcitic  layers.  Pearls  are  merely  loose  portions 
of  the  inner  layer  secreted  by  the  mantle  surface,  usually  around  foreign 
bodies  which  have  reached  the  interior  of  the  shell  and  set  up  Irritation  there. 

In  the  majority  of  Pelecypods  the  valves  form  a  nearly  complete  defence ; 
in  borers,  burrowers  and  a  few  degenerate  types,  the  valves  cover  less  and 
less  surface  in  proportion  to  that  which  is  bare ;  in  a  few  the  mantle  is  re- 
flected  so  as  to  envelop  more  or  less  of  the  outer  surface  of  the  valves ;  and 
finally,  in  Chlamydoconcha,  the  valves  are  permanently  internal,  separately 
encysted,  with  the  ligament  isolated  and  encysted  between  them.  No 
example  is  known  of  a  Pelecypod  absolutely  destitute  of  valves  in  the  adult 
State. 

The  valves  of  the  shell  are  in  general  substantially  equal ;  but  sometimes 
they  are  unequal,  especially  in  sessile  or  sedentary  forms  ;  and  rarely  they 
are  spirally  twisted,  as  in  Stavelia  and  Spirodomus.  The  hinge  or  articulus 
comprises  the  whole  articulating  apparatus — hinge  plate,  teeth,  ligament,  etc. ; 
the  primitive  hinge,  which  is  coextensive  with  the  ligament,  is  distinguished 
by  Hyatt  as  the  cardo.  The  cardinal  axis,  or  right  line  forming  the  axis  of 
revolution  of  the  hinge,  is  parallel  with  the  antero-posterior  axis  of  the 
animal  (as  determined  by  a  line  drawn  through  the  mouth  and  posterior 
adductor)  in  the  ordinary  Teleodesmacea ;  but  in  the  winged  Prionodesmacea, 


426  MOLLUSCA  phylum  vi 

such  as  Ostrea^  Pedalion,  etc.,  the  two  axes  are  at  a  considerable  angle  with  each 
other. 

The  dental  armature  is  usually  situated  on  the  dorsal  margin,  which  for 
this  reason  is  called  the  cardinaL  margin.  It  comprises  the  teeth,  or  project- 
ing  processes  and  sockets,  usually  alternating  in  the  single  valve,  and  opposite 
with  respect  to  both  valves.  In  the  more  modern  and  perfected  types,  the 
Cardinal  margin  is  reinforced  by  a  vertical  deposit  of  shell  in  the  form  of  a 
lamina  called  the  hinge  plate,  upon  which  the  teeth  are  set.  Above  the  hinge 
plate  in  each  valve  rise  the  beaks  or  umbones,  which  are  usually  curved 
toward  the  anterior  end  of  the  shell  (prosogyrate),  but  are  sometimes  directed 
back  ward  (opisthogyrate)  or  outward  (spirogyrate). 

According  to  the  ordinary  terminology,  the  height  of  a  Pelecypod  is 
measured  on  a  vertical  line  from  the  beaks  to  the  ventral  margin ;  the  length 
corresponds  to  the  greatest  distance  between  the  margins  parallel  with  the 
antero-posterior  axis  above  defined  ;  and  the  thickness,  or  diameter,  is  measured 
by  a  line  at  right  angles  to  the  vertical  plane  descending  from  the  cardinal 
axis  (Fig.  641).  When  the  shell  is  placed  with  the  oral  end  anterior,  the 
valves  are  termed  right  and  left  respectively,  as  viewed  from  above  the 
articulus.  The  portion  of  the  shell  anterior  to  the  beaks  is  usually  shorter 
than  that  behind  them,  except  in  such  forms  as  Donax  or  Nucula. 

Viewed  laterally,  most  Pelecypod  valves  may  be  divided  into  regions, 
corresponding  in  the  main  to  the  Disposition  of  the  internal  organs.  The  oral 
area  extends  from  the  anterior  end  of  the  cardinal  line  to  the  anterior  side  of 
the  pedal  area.  The  latter  is  often  marked  by  a  swelling  of  the  valves,  and 
sometimes  by  a  sinus  (Pholas) ;  it  extends  backward  to  a  point  where  the 
branchial  crest,  radiating  from  the  beaks,  forms  the  anterior  boundary  of  the 
siphonal  area.  The  dorsal  or  posterior  limit  of  the  siphonal  area  is  marked  by 
an  angle  in  the  incremental  lines ;  and  above  this,  extending  to  the  posterior 
end  of  the  cardinal  line,  is  the  intestinal  area.  In  the  alate  forms,  like  Fteria, 
the  wings  usually  called  anterior  and  posterior  are  really,  with  reference  to 
the  antero-posterior  axis  of  the  animal,  dorsal  and  ventral. 

In  certain  borers,  the  siphons  are  greatly  produced  beyond  the  valves,  and 
a  calcareous  tube  is  secreted,  lining  the  burrow  ;  the  valves,  situated  at  the 
anterior  end  of  the  boring,  either  lie  free,  or  are  partially  or  wholly  fused 
with  the  tube.  In  the  Pholadidae  the  naked  portions  of  the  animal  between 
the  edges  of  the  valves  are  often  protected  by  additional  shelly  pieces,  which 
are  organically  separate  from  the  valves ;  and  some  burrowers  have  the  free 
ends  of  the  siphons  protected  by  leathery  or  calcareous  shields.  In  the 
Teredinidae  these  shields  are  specially  modified  to  protect  the  entrance  of  the 
burrow,  and  are  called  "  pallets." 

Ornamentation. — The  external  ornamentation  of  the  valves  is  always  a 
conspicuous  character.  It  comprises  (beside  the  concentric  or  incremental 
lines  which  indicate  the  successive  additions  to  the  shell  margin,  and  are 
believed  to  coincide  with  resting  stages  during  the  process  of  growth)  radial 
or  concentric  Striae,  ridges,  ribs,  folds,  nodes,  spines  or  foliaceous  processes. 
These  are  supposed  to  arise  from  temporary  or  permanent  modifications  of 
the  mantle  margins,  such  as  papillae,  minute  tentacular  or  proliferate 
processes. 

Above  the  hinge  line,  in  archaic  types,  is  an  area  often  set  off  by  an 
impressed  line  and  called  the  cardinal  area.     In  the  more  perfected  modern 


OLASS  I  PELECYPODA  427 

forms  this  area  is  commonly  divided ;  a  heart-shaped  space  in  front  of  the 
beaks,  and  bounded  by  a  ridge  or  groove,  being  known  as  the  lunule;  and  a 
more  elongated  space  extending  backward  from  the  beaks  being  designated  the 
escutcheon.  Both  areas  often  have  a  special  sculpture,  differing  from  that  of 
the  remainder  of  the  shell. 

Another  form  of  ornamentation  is  sometimes  found  on  the  opposed  inner 
margins  of  the  valves,  away  from  the  hinge  line,  as  in  Digitaria  (Fig.  756), 
or  Transennella ;  it  probably  aids  in  preventing  a  lateral  displacement  of  the 
valves.  In  general,  all  ornamentation  may  be  confidently  ascribed  to  a 
dynamic  origin. 

Internal  Characters.  Soft  Parts. — The  Pelecypod  body  is  enclosed 
within  two  thin,  partly  fleshy  mantle  lobes,  which  are  united  or  continuous 
below  the  cardinal  margin,  and  open  or  partially  united  at  other  points  on 
their  periphery.  Within  the  mantle  lobes  are  the  visceral  mass  including 
the  internal  organs,  the  gills  or  denidia,  the  foot  and  the  palpi.  When  the 
mantle  edges  are  united  so  as  to  form  tubes  for  the  entrance  and  discharge  of 
water,  such  tubes  are  called  siphons.  These  organs,  all  of  which  have  been 
utilised  in  Classification,  will  be  considered  separately. 

The  mantle  is  closely  applied  to  the  surface  of  the  valves,  and  is  usually 
attached  to  them  along  a  line  near  its  periphery.  This  line  is  indicated  by  a 
continuous  scar  or  Impression  upon  the  inner  surface  of  the  valves,  termed 
the  pallial  line.  Outside  the  pallial  line  a  portion  of  the  margin  is  free  and 
usually  thickened.  In  it  are  contained  the  glands  which  secrete  the  shell, 
and  also  pigment  glands ;  it  is  ornamented  by  papillae,  tentacular  processes, 
etc.,  and  is  sometimes  furnished  with  visual  organs  of  a  primitive  sort. 
Certain  archaic  forms  had  no  distinct  pallial  line,  the  mantle  being  organi- 
cally  attached  over  a  more  or  less  irregulär  area.  The  ends  of  the  pallial 
line  are  commonly  continuous  with  the  scars  of  the  adductor  muscles. 

The  majority  of  Pelecypods  have  two  adductor  muscles,  and  are  distinguished 
accordingly  as  Dimyarian,  or  Homomyarian ;  in  some  the  anterior  muscle  is 
absent  or  degenerate  (Monomyaria) ;  and  in  others  an  intermediate  condition 
obtains  (Heteromyaria  or  Anisomyaria).  The  number  and  position  of  the 
adductors  was  f ormerly  accepted  as  a  fundamental  feature  in  Classification, 
although  many  difficulties  were  presented  by  exceptional  cases.  Eecent 
researches  have  shown  that  an  absolute  foundation  for  Classification  cannot 
be  afForded  by  the  number  of  adductors ;  but  still,  if  allowance  be  made  for 
degeneration  caused  by  inequilaterality,  torsion  and  other  causes,  the  general 
myarian  types  harmonise  fairly  well  with  the  larger  divisions  based  on  the 
totality  of  characters. 

The  visceral  mass,  as  a  rule,  occupies  the  Upper  portion  of  the  shell, 
and  contains  the  heart,  intestinal  canal,  generative  organs,  renal  and  other 
glands.  The  rectum  usually  lies  above  the  posterior  adductor,  and  dis- 
charges  into  the  anal  siphon,  when  present.  The  mouth  is  placed  at  the 
forward  end  of  the  visceral  mass  below  the  anterior  adductor,  and  is  commonly 
furnished  on  each  side  with  a  pair  of  leaf-like  expansions  of  the  integument 
called  ]i)<^lph  which  are  ciliate  internally,  and  serve  to  conduct  alimentary 
matter  from  the  gills  to  the  mouth.  Palpi  are  seldom  wanting,  and  their 
form  and  character  remains  fairly  constant  throughout  a  number  of  groups. 
The  mouth  itself  is  unarmed,  and  the  alimentary  canal  is  more  or  less  bent, 
usually  exhibiting  a  dilation  which  is  regarded  as  the  stomach. 


428  MOLLUSCA  phylum  vi 

The  Foot. — From  the  ventral  surface  of  the  visceral  mass  projects  an 
extensile  muscular  organ,  known  as  the  foot,  which  is  capable  of  being  pro- 
truded  beyond  the  margins  of  the  valves,  or  entirely  retracted  within  the 
mantle  lobes.  The  muscles  serving  to  move  this  organ  are  inserted  upon  the 
Shell  near  the  adductor  scars,  leaving  small  accessory  impressions.  In  a 
large  majority  of  bivalves,  the  foot  has  the  familiär  hatchet-shape  from  which 
the  class  name  is  derived,  but  as  an  organ  of  locomotion,  tactile  use,  and 
possibly  prehension,  it  is  modified  for  special  uses  in  many  forms.  A  few 
Pelecypods,  such  as  Osfrea,  have  the  foot  altogether  aborted,  though  remnants  of 
its  retractor  muscles  exist  and  are  attached  to  the  valves ;  and  in  some  cases 
{Pholadomya,  Halicardia)  an  accessory  foot-like  organ,  or  "  opisthopodium," 
is  developed  at  the  posterior  end  of  the  visceral  mass. 

In  many  Pelecypods  the  foot  is  provided  with  a  gland  secreting  horny 
matter  which  solidifies  in  threads  after  extrusion,  forming  a  fixative  tuft  or 
cable  called  the  byssus,  by  which  the  animal  adheres  to  extraneous  objects. 
Some  sessile  genera  have  the  byssus  more  or  less  calcified,  when  it  forms  a 
shelly  plug  closing  a  sinus  or  foramen  in  one  of  the  valves  through  which  it 
passes.  Many  of  the  Pectinidae  have  a  comb-like  series  of  denticles  (denolium) 
on  the  edge  of  the  byssal  sinus,  in  which  the  byssal  threads  rest.  In  perma- 
nently  sessile  forms,  the  byssus  is  usually  absent. 

Gills. — On  either  side  of  the  visceral  mass  above  the  foot  and  usually 
extending  from  the  palpi  to  the  posterior  adductors  are  the  gills  or  denidia. 
In  a  general  way  the  ctenidium  is  composed  of  a  stem  carrying  a  nerve  and 
blood-vessel,  from  which  on  each  side  leaflets  or  slender  filaments  are  given 
out  laterally.  In  the  more  archaic  types  (Nucula,  Yoldia,  Solemya)  these  gills 
are  plate-like,  not  organically  united  except  by  the  stem,  though  in  some 
cases  attaining  a  solidarity  as  a  mass,  by  the  interlocking  of  very  large  cilia, 
distributed  in  bands  or  patches  on  the  opposed  surfaces  of  individual  plates. 

These  plate-like  gills  are  termed  foliobranchiate  or  protobranchiate. 
According  to  their  structure,  other  types  of  gills  are  intermediate  between 
these  and  the  so-called  "  filibranchiate,"  in  which  the  plates  are  elongated  and 
strap-like,  and  the  "  reticulate,"  in  which  the  filaments  are  united  by  cross 
conduits  in  a  net-like  manner.  Attempts  have  been  made  to  employ  the 
various  types  of  gills  as  fundamental  characters  in  Classification,  but  experience 
has  shown  that  they  cannot  be  depended  upon  as  the  exclusive  basis  of  any 
systematic  arrangement. 

Siphons. — When  the  mantle  lobes  are  united,  two  posterior  openings,  more 

or  less  tubulär,  are  always  present 
(Fig.  640).  The  dorsal  tube,  called 
the  dorsal  or  anal  siphon,  serves  for 
the  discharge  of  water  which  has 
j,  been  inhaled  through  the  ventral 
Fifi.  640.  or  branchial  siphon,  carried  to  the 

Saxicava   arctim    Lam.     Animal    with    closed   mantle    gÜls,    dcprivcd    of     itS    OXygeU    and 

ges,  showing  foot  (p),  protruding  from  the  pedal  open-       j-i,i  j.-   ^  j    j.i,  n    j 

mg,  and  anal  (s)  and  branchial  (s')  sTphons.    Natural  siL        edlble    particles,  and  then  expelled. 

The  anal  siphon  also  carries  efFete 
matters  from  the  rectum,  and  sometimes  ova  are  discharged  in  the  same 
way.  The  tubes  are  sometimes  adherent  or  enclosed  in  the  same  envelope, 
and  sometimes  separate  to  their  base ;  in  general,  however,  a  septum  or 
partition  exists  between  the  two  passages,  thus  avoiding  the  mixture  of  the 


CLASS I 


PELECYPODA 


429 


two  currents.  The  siphonal  septum  is  frequently  carried  forward  internally, 
or  supplemented  by  a  junction  of  the  gills  in  such  manner  as  to  form  a 
practically  continuous  partition  between  the  anal  and  branchial  regions 
within  the  mantle.  The  siphons  are  always  contractile,  and,  except  in 
sedentary  burrowers,  usually  retractile  within  the  shell. 

The  siphons,  being  a  local  modification  of  the  mantle  margin,  receive  their 
musculation  from  the  same  source.  In  general,  the  muscles  have  spread 
inward,  pari  passu  with  the  increase  in  length  of  the  organ  to  be  retracted, 
and  their  Insertion  on  the  valve  leaves  an  angular  scar  called  the  pallial  sinus, 
which  is  an  important  aid  in  Classification  of  the  minor  groups.  It  has  some- 
times  been  assumed  that  the  absence  of  this  sinus  was  evidence  of  the 
asiphonate  character  of  the  species,  but  the  example  of  Lucina,  Cuspidaria, 
and  several  other  siphonate  forms  which  have  no  pallial  sinus  show  that  this 
is  not  necessarily  true.     Formerly,  when  the  character  of  the  pallial  line  was 


Lutraria  elUptica  Roissy.  Interior  of  left  valve  show- 
ing  i>allial  line  (p) ;  pallial  sinus  (s)  ;  anterior  (a)  and  pos- 
terior (o/)  adductor  scars  ;  and  resiliifer  (l).  hv,  Length  ; 
ui,  Heiglit  of  the  shell.     '■^/^  natural  size. 


Fio.  642. 


Crassatell  ites  plumbeus  (Chem.).  Interior  of  left 
valve  showing  entire  pallial  line  (m) ;  anterior  (a) 
and  posterior  («')  adductor  scars ;  and  resiliifer 
(0.    2/g  natural  size. 


regarded  as  of  prime  importance,  the  Pelecypods  with  a  sinus  were  called 
Sinupalliata  (Fig.  641),  and  those  without,  Integripalliata  (Fig.  642). 

The  Hinge. — The  origin  both  of  the  hinge  structure  and  the  ornamentation 
of  the  shell  can  be  perhaps  best  understood  by  a  consideration  of  what  is 
known  regarding  the  archetype  of  the  class,  and  by  noticing  the  changes  that 
have  since  been  introduced.  The  original  protopelecypod  was  small,  thin, 
symmetrical,  sub-circular  or  oval,  with  a  short  external  ligament  equally  dis- 
posed  on  each  side  of  the  beak  along  the  hinge  line.  The  mantle  was  not 
uniformly  attached  to  the  shell  along  a  pallial  line,  as  in  modern  Pelecypods, 
but  adhered  more  or  less  irregularly  and  was  not  provided  with  extrusile 
siphonal  tubes.  The  adductor  muscles  were  sub-equal,  symmetrical,  and 
situated  high  up  in  the  valves.  The  surface  of  the  valves  was  smooth,  or 
(probably  in  connection  with  the  development  of  tactile  papillae  on  the  mantle 
edge)  radiately  ribbed.  These  conclusions  are  justified  not  only  by  inference 
and  by  recent  investigations  on  the  morphology  of  the  prodissoconch,  but  by 
the  characters  of  the  most  archaic  Pelecypods,  summarised  by  Neumayr  under 
the  name  of  Palaeoconcha. 

Since  the  general  form  of  the  Pelecypod  depends  upon  its  principal 
anatomical  characters  (the  size,  number  and  position  of  the  muscles,  the 
presence,  size  and  character  of  siphons,  byssus,  etc.),  then,  to  a  certain 
limited  extent,  especially  in  the  modification  of  the  primitive  simple  Palaeo- 


430  MOLLUSCA  phylum  vi 

conchs,  it  is  piain  that  the  differences  of  form  would  tnarch  with  the  respective 
anatomical  differences.  For  example,  those  forms  which  retained  the  simple 
open  mantle  and  sub-equal  adductors  would  continue  to  be  of  a  rounded  and 
symmetrical  shape ;  while  those  which  tended  to  produce  elongate  siphons,  or 
in  which  marked  inequality  of  the  adductors  was  developed,  would  probably 
present  more  elongate  or  triangulär  outlines.  The  differences  of  form  would 
necessarily  react  upon  the  developing  hinge,  from  the  inevitable  Operation  of 
physical  laws,  and  thus  tend  to  produce  in  connection  with  particular  lines  of 
evolution  of  form,  particular  types  of  hinge. 

The  recent  researches  of  Bernard  and  Simroth  have  developed  the  fact 
that  in  some  Pelecypoda  the  ctenidium  originates  as  a  lateral  plate,  which 
becomes  transversely  folded,  and  in  which  the  reticulate  form  results  from 
subsequent  perforations  between  the  folds,  and  not  from  the  concrescence  of 
originally  separate  filaments,  as  has  been  hitherto  supposed  to  be  the  invari- 
able mode. 

Neumayr  has  shown  that,  among  the  Palaeoconcha,  ribbing  existed  in 
various  species  along  the  dorsal  as  well  as  the  other  margin,  and  that  it  pro- 
duced  denticulations  there  ;  and  that  when  these  denticulations  had  become 
a  fixed  specific  character,  the  ribbing  disappeared  from  the  area  above  the 
hinge  margin. 

In  this  way  (as  analogically  in  the  Recent  Crenella,  etc.)  the  Initiation  of 
the  processes  called  hinge  teeth  began.  Such  projections,  interlocking  at  a 
time  when  the  serrations  of  the  other  margin  of  the  open  valves  could  be  of 
little  assistance  in  securing  rigidity,  offered  a  means  of  defence  of  the  greatest 
importance  when  fully  developed  by  natural  selection,  one  which  would  be 
useful  at  every  stage  of  development,  but  would  increase  in  usefulness  with 
increase  in  size.  In  fact,  this  was  just  such  a  feature  as  would  lend  itself  to 
the  füllest  Operation  of  natural  selection.  Once  well  initiated,  its  progress 
was  inevitable,  and  its  variety  and  complexity  only  a  question  of  time. 

From  recent  studies  by  Bernard  of  the  development  of  hinge  teeth  in 
nepionic  Pelecypods  of  many  groups,  it  appears  that  in  most  if  not  all  Priono- 
desmacea  and  some  Teleodesmacea  there  is  first  developed  on  each  side  of  the 
ligament  (or  behind  it  in  Ostrea)  a  series  of  transverse  denticulations  or 
minute  taxodont  teeth,  f orming  what  has  been  called  a  provinculum  or  primi- 
tive hinge,  independent  (so  far  as  yet  observed)  of  the  permanent  dentition. 
The  latter  begins  subsequently  by  the  development  of  distinct  laminae  on 
the  hinge  plate.  In  the  Teleodesmacea,  toward  the  ends  of  the  hinge  plate 
the  primitive  lamellae  originate  below  the  provinculum  or  in  its  absence,  and 
grow  proximally.  The  inner  ends  of  the  anterior  lamellae  become  hooked, 
and  these  hooks  separate  from  the  distal  portions  which  remain  to  form  the 
anterior  laterals,  while  the  hooks  develop  into  the  cardinals,  and  the  posterior 
lamellae  into  the  posterior  lateral  teeth.  The  facts  point,  of  course,  to  the 
provinculum  as  representative  of  the  primitive  hinge  as  observed  in  many 
Palaeoconchs ;  but  the  gap  between  the  provinculum  and  the  beginnings  of 
the  permanent  dentition,  indicates  a  suppression  of  certain  developmental 
stages  which  only  further  researches  can  supply. 

The  dynamical  origin  of  the  shelly  processes  of  the  hinge,  which  we  call 
teeth,  has  only  recently  attracted  attention.  In  this  work  Neumayr  led  the 
way,  and  his  contributions  have  been  most  valuable ;  yet,  as  often  happens 
with  pioneer  work,  he  failed  to  grasp  fully  all  the  details  of  the  subject,  and 


CLASS  I 


PELECYPODA 


431 


the  nomenclature  he  proposed  has  required  revision.  Several  groups  or 
kinds  of  teeth  can  easily  be  distinguished.  These  are  not  iiecessaiily  funda- 
mental, since  the  teeth,  being  largely  moulded  by  the  dynamics  of  their 
Situation,  change  with  the  influences  to  which  their  form  is  due,  and  in  course 
of  time  may  become  obsolete  froin  disuse  (Anodon),  or  modified  so  as  to 
simulate  the  teeth  of  groups  with  widely  different  pedigree  (Nucula,  Mutela, 
Plicattda,  Trigonia).  In  general,  however,  at  any  given  time,  the  types  of 
teeth  are  good  evidence  of  the  relationship  of  forms  to  which  they  are 
common,  especially  if  the  development  from  the  younger  stages  of  the  species 
under  comparison  proceeds  along  similar  lines. 

The  modifications  of  the  hinge  now  generally  recognised  are  as  follows : — 

In  the  Taxodonta  the  hinge  is  composed  of  alternating  teeth  and  sockets, 

mostly  similar,  and  frequently  forming  a  long  series,  as  in  Area  (Fig.  643,  A) 


Taxodont  liinges. 


Fio.  G43. 
A,  Area,  with  external  ligament. 
with  internal  resilium. 


B,  Leda, 


Fio.  C44. 

Schizodont  hinge. 
Trigonia  pectinata 
Lam.  Recent ;  Aus- 
tralia. 


or  Leda  (Fig.  643,  B).  The  Schizodonta  have  heavy,  amorphous,  variable 
teeth,  often  obscurely  divided  into  sub-umbonal  (pseudocardinal)  and  lateral 
(posterior)  elements,  as  in  Trigonia  (Fig.  644),  Unio  (Fig.  645),  and  Schizodus. 

In  the  Isodonta  the  original  taxodont 
provinculum  is  often  replaced  in  the  adult 
by  a  hinge  structure  derived  from  tM^o 
ridges  (the  "auricular  crura")  originally 
diverging  below  the  beaks.  This  becomes, 
in  the  most  specialised  forms,  an  elaborate 
interlocking  arrangement  of  two  concentric  ^\ 
pairs  of  teeth  and  sockets,  which  cannot 
be  separated  without  fracture,  as  in  Spon- 
dylus  (Fig.  718).     In  less  specialised  forms, 

such    as    Peden,    the    provinculum     becomes         schizodont  hinge  of  Unio  stachei  Neumayr, 
,       ,    ,  ,    ,,  ^  1  „j.*   ii„    J^     ahowing    pseudocardinal    and    lateral    teeth. 

obsolete,  and  the  crura  only  partially  de-  pnocene ;  siavonia. 
velop. 

The  Di/sodonta  of  Neumayr  was  originally  a  heterogeneous  group,  and  the 
term  is  now  restricted  to  that  division  having  a  feeble  hinge  structure,  whose 
origin  is  more  or  less  palpably  derived  from  external  sculpture  impinging 
upon  the  hinge  line,  as  in  MijoconcJia  (Fig.  646),  Pachymytiliis  (Fig.  647),  and 
Crenella. 

The  preceding  groups,  together  with  the  edentulous  Solemyacea,  constitute 
the  Order  Prionodesmacea,  which  is  knit  together  by  Community  of  descent 
still  traceable  in  their  anatomy. 


Fio.  645. 


432 


MOLLUSCA 


PHYLÜM  VI 


Fig.  646. 

Dysodont  hinge  of 
Myoeoncha  striatula 
Goldf.  LowerOolite; 
Bayeux,     Calvados. 

Vi- 


d'Orb. 

France. 


The  Fantodonta  are  a  small  group  of  Paleozoic  forms  whose  dentition 
partakes  of   the  syiithetic  character  of   the  more  archaic  forms,   wliile   fore- 

shadowing  the  f uture  teleo- 
dont  types.  In  this  group 
the  laterals  may  exceed  a 
pair  in  a  single  group,  which 
is  never  the  case  in  the 
modern  types.  Orthodontiscus 
and  AUodesma  are  examples. 
The  Diogenodonta  are  the 
modern  and  perfected  forms 
in  which  there  are  difFeren- 
tiated  lateral  and  true  car- 
dinal  teeth  upon  a  hinge 
plate,  the  former  never  ex- 
ceeding  two,  nor  the  latter 
three  in  any  one  group. 
Ästarte  (Fig.   754),  Crassatel- 

Dy,odont  hinge  ot'pachymytilus  petasus    UteS  (Fig.   642)  and    CorUcula 
Coral  Rag;    Ooulange-sur-Yonne,    (^jg,   761)  are  examples. 

The  Cydodonta  exhibit 
extreme  torsion  in  their  dentition,  which  cijrves  out  from  under  the  beaks 
and  is  not  set  upon  a  flat  hinge  plate.  Isocardia  (Fig.  806),  Tridacna  and 
Cardium  (Fig.  801)  are  examples. 

In  the  Teleodonta  are  found  the  most  highly  perfected  types  of  hinge. 
The  characters  of  the  less  specialised  forms  hardly  difFer  from  those  of  the 
Diogenodonta,  but  they  are  placed  here  on  account  of  their  obvious  affinities 
as  shown  by  other  characters.  The  most  specialised  forms  add  to  the  ordinary 
Cardinal  series  of  the  Teleodesmacea  (10101  )  either  a  roughened  area,  as  in 
Venus;  a  series  of  extra  cardinals,  as  in  Tivela;  or  accessory  lamellae,  as  in 
Madra,  making  the  hinge  more  complicated  or  efficient.  Cytherea  (Fig.  809), 
Mactra  (Fig.  824),  Venus  mercenaria  and  Tivela  are  examples. 

Several  of  these  forms  were  included  by  Neumayr  in  a  group  called  Des- 
modonta,  which  he  founded  on  such  types  as  Madra  under  a  misapprehension 
as  to  the  character  of  the  hinge ;  almost  all  of  the  others  were  included  in 
his  Heterodonta,  which,  construed  strictly,  would  take  in  all  dentiferous 
Pelecypods,  since  the  alternation  forming  its  essential  character  is  inseparable 
from  the  possession  of  functional  teeth. 

The  Asthenodonta  comprise  borers  and  burrowers  in  which  the  teeth  have 
become  obsolete  from  disuse.  Corhula  (Fig.  828),  Mya  (Fig.  827)  and  Fholas 
(Fig.  833)  are  illustrative  types.  In  the  last-named  a  remarkable  develop- 
ment  of  the  sub-umbonal  attachment  of  the  mantle  has  produced  a  myophore 
which  is  sometimes  wrongly  interpreted  as  a  tooth.  The  exceptional  develop- 
ment  of  this  f eature  is  explained  by  the  dynamics  of  Pholad  existence. 

The  above  groups  form  the  orderTeleodesmacea,  and  dentally  are  intimately 
related.     Recent  studies  by  Bernard  ^  as  to  the  genesis  of  individual  teeth 

^  Bernard,  F.,  Sur  le  developpement  et  la  morpliologie  de  la  coquille  chez  les  lamellibranclies. 
Bull.  Soc.  Geol.  France  [3],  1895-97,  vols.  xxiii.,  xxiv.  —  Vest,  W.  von,  Über  die  Bildung  und 
Entwicklung  des  Bivalvenschlosses.  Verh.  Siebenb.  Vereins  Naturw.,  1895-96,  vol.  xlviii. — 
Dali,  W.  II.,  On  the  hinge  of  the  Pelecypods  and  its  development.  Amer.  Journ.  Sei,,  1889  [3],  vol. 
xxxviii. — Reis,  0.,  Das  Ligament  der  Bivalven.   Jahresh.  Ver,  Vaterl.  Naturk.  Württ.,  1902,  vol.  Iviii. 


CLASs  I  PELECYPODA  433 

among  mcmbers  of  this  order  show  great  uniformity  in  the  early  stages. 
But  inasmuch  as  these  observations  are  dependent  upoii  the  mode  of  growth 
in  highly  specialised  Pelecypods,  in  which  the  development  of  teeth  is  largely 
secondary,  care  must  be  taken  not  to  confound  these  processes  with  those  by 
which  hinge  teeth  were  originally  initiated  in  edentulous  Protopelecypods. 

Finally,  in  the  Anomalodesmacea  we  have  a  tribe  of  burrowers  which  have 
preserved  to  the  present  day  some  of  the  features  which  characterised  the 
edentulous  Protopelecypods  of  ancient  geological  time.  The  small  teeth  of 
the  neaily  edentulous  hinge  may  sometimes  be  associated  with  the  submersion 
of  the  resilium  and  the  development  of  a  chondrophore,  but  in  other  cases 
they  may  be  the  remnants  of  hinge  teeth  acquired  in  the  ordinary  way  early 
in  the  geological  history  of  the  group. 

Dental  Formulae. — For  the  purpose  of  recording  compactly  the  number 
and  character  of  the  teeth  in  adult  Pelecypods,  a  formula  has  been  suggested 
by  Steinmann,  which,  somewhat  amplified,  is  as  follows  : — 

Let  L  represent  the  left  and  E  the  right  valve,  and  the  teeth  be  repre- 
sented  by  units ;  the  sockets  into  which  teeth  of  the  opposite  valve  fit  by 
zeros ;  the  resilium  or  chondrophore  by  C ;  the  laterals  by  1 ;  the  clasping 
laminae  which  receive  the  laterals  by  m,  if  single  ;  if  double,  by  m2.  Where 
two  taxodont  rows  meet  on  one  hinge  margin  and  are  not  separated  by  a 
resilium,  as  in  Glycimeris,  let  their  junction  be  marked  by  a  period.  Obsolete 
or  feeble  teeth  may  be  represented  by  the  italicised  symbol  for  normal  teeth. 
For  amorphous,  interlocking  masses,  which  cannot  be  classified  as  teeth,  and 
are  of  varied  origin,  the  symbol  x  is  adopted.  The  enumeration  begins  at  the 
posterior  end,  and  the  right-hand  end  of  the  formula  is  always  anterior. 

Thus,  types    of    teleodont  dentition  may  be  represented  as   follows : — 

Astarte  horealis,  ^  ■,  ,^,^^r-  ;  Crassatellites  antillarum,  ^  .  ^,7^  :  Fenus  mercenaria, 
Rxioioi  ^^^  ^^^^  ^^^^  ^  represents  the  rough  area  below  the  ligament). 

In  investigating  the  genesis  of  the  individual  hinge  teeth  in  various 
genera  of  the  Teleodesmacea,  Munier-Chalmas  and  Bernard  have  adopted  the 
following  formula,  which  expresses  at  once  the  origin  and  position  on  the 
hinge  of  the  several  teeth.  In  the  majority  of  cases  the  teeth  appear  to  be 
derived  from  two  primitive  pairs  of  lamellae  in  each  valve,  one  pair  anterior 
and  one  posterior.  Each  adult  tooth  is  designated  by  an  Arabic  numeral 
corresponding  to  the  primitive  lamella  from  which  it  is  derived,  with  a  for 
the  anterior  and  b  for  the  posterior  tooth  when  a  single  primitive  lamella 
gives  rise  to  two  teeth.  The  laterals  are  counted  from  below  upward  in 
Koman  numerals,  the  odd  numbers  belonging  in  every  case  to  the  right,  and 
the  even  numbers  to  the  left  valve.  If  it  is  necessary  to  name  a  socket  it 
receives  the  designation  of  the  tooth  which  occupies  it,  supplemented  by  an 
accent  (').  A  and  P  stand  for  anterior  and  posterior,  L  for  lateral,  and  CA 
for  Cardinal  teeth.  Finally,  if  a  tooth  disappears,  its  place  is  indicated  by 
a  zero  with  an  index  showing  which  particular  tooth  it  was.  The  numeration 
of  the  cardinals  always  begins  with  the  right  median  cardinal  tooth.  Thus, 
CAl  =  median  cardinal  of  the  right  valve,  CA2b  =  left  median  cardinal  derived 
from  the  posterior  part  of  primitive  lamella  number  two;  LA  I  =  ventral 
anterior  lateral,  LP  III  --=  dorsal  posterior  lateral,  etc. 

Ligament. — The  ligament  which  unites  the  two  valves,  as  stated  above,  is 
primitively  continuous  with  them  as  the  uncalcified  part  of  the  primitive 
VOL.  I  2  F 


434  MOLLUSCA  phylum  vi 

pellicle  secreted  by  the  original  shell  gland ;  it  is  therefore  neither  external 
nor  internal.  With  its  subsequent  differentiation,  and  the  thickening  of  the 
valves  by  calcification  deposited  about  it,  it  occupies  a  depression  in  the 
Cardinal  margin  which  Bernard  has  regarded  as  internal.  In  a  sense  it  is 
internal,  but  its  position  at  this  stage  is  not  significant,  and  there  is  no 
fundamental  difference  between  the  cases.  The  differentiation  in  function 
and  structure  which  we  find  in  the  adnlt  between  the  ligament,  properly 
so-called,  and  the  "  internal  ligament "  or  resilium,  is  a  later  development. 

The  ligament  may  be  regarded  as  a  fundamental  character  of  Pelecypods, 
and  is  universally  present,  though  in  some  cases  as  a  mere  degraded  rudiment 
(Pholadacea) ;  it  may  be  separated  from  the  valves  and  functionless  {Chlamydo- 
concha),  or  present  only  in  the  young  stages  and  lost  through  specialisation 
due  to  the  sessile  habit  (Rudistids). 

As  the  most  important  factor  in  the  mechanism  of  the  valves,  the  liga- 
ment has  undoubtedly  developed  with  the  evolution  of  the  class,  and  its 
chief  modifications  date  from  the  earliest  period  in  the  life-history  of  the 
group.  The  function  of  the  original  ligament  was  that  of  an  external  link 
between  the  valves  having  the  essential  nature  of  a  C-spring.  That  is,  the 
insertion  of  the  ligament  edges  on  the  cardinal  margins,  or,  at  a  later  period, 
on  thickened  ridges  or  nymphae  by  which  these  margins  are  reinforced  to  bear 
strains,  resulted  in  the  following  conditions  : — The  valves  being  held  together 
and,  in  closing,  approximated  by  the  contraction  of  the  adductor  muscles,  the 
preservation  of  their  precise  apposition,  marginally,  is  due  to  a  rotary  motion, 
exerted  along  the  axis  of  the  ligament,  which  pulls  the  attached  edges  of  the 
ligament  nearer  to  each  other  and  exerts  a  strain  on  its  cylindrical  exterior. 
This  Operation,  with  a  thin  ligament,  involves  a  tensile  strain  on  the  whole 
cylinder;  with  a  thick  ligament  the  external  layers  are  strained  and  the 
internal  layers  compressed,  so  that  to  the  tensile  elasticity  of  the  external 
layers  is  added  the  compressional  elasticity  of  the  internal  portion.  The 
result  of  the  differing  strains  to  which  the  several  layers  of  the  ligament  are 
subjected  brings  about  a  diiference  of  structure,  and,  whenever  the  ligament 
becomes  deep-seated,  there  is  a  tendency  for  the  respective  parts  to  separate 
along  the  line  where  the  two  sets  of  strains  approximate.  We  then  have  two 
elastic  bodies,  operating  reciprocally  in  opposite  directions,  the  outer  or  liga- 
ment proper  tending  to  pull  the  valves  open  to  a  certain  distance  correspond- 
ing  to  its  ränge  of  tensional  elasticity ;  and  the  other  or  resilium  (for  which 
the  objectionable  terms  "  cartilage  "  and  "  internal  ligament "  have  been  used) 
tending  to  push  them  open  to  an  extent  corresponding  to  its  ränge  of  expansion. 

The  ligament  proper  is  of  a  more  or  less  corneous  nature,  tough  and  semi- 
translucent  beneath  its  external  surface.  When  dry  it  has  a  vitreous  fracture, 
and  often  shows  hardly  any  fibrous  texture. 

The  resilium  is  distinctly  lamellar  or  composed  of  horny  fibres,  which  are 
apt  to  give  a  pearly  sheen  to  its  broken  surface.  There  is  often  a  more  or 
less  extensive  intermixture  of  lime  in  its  substance,  which  may  be  diffused,  or 
may  be  especially  concentrated  along  the  median  plane.  As  may  be  seen  by 
examining  the  unbroken  resilium  (as  in  Madra),  this  organ  in  such  cases  has 
something  of  an  hour-glass  shape ;  the  ends  which  fit  into  the  "  cartilage  pits  " 
or  resiliifers  being  more  expanded  than  the  centre  between  them.  The  deposit 
of  lime  in  the  form  of  an  accessory  shelly  piece,  usually  termed  the  ossiculum 
or  lithodesmaj  serves  for  the  reinforcement  of  the  resilium. 


CLASs  I  PELECYPODA  435 

For  the  type  of  ligament  which  extends  on  both  sides  of  the  beaks, 
Neumayr  adopts  the  designation  amphidetic ;  and  for  the  more  perfected  type 
which  has  been  withdrawn  wholly  behind  the  beaks,  he  employs  the  term 
opisthodetic  (Fig.  648).  Glycimeris  offers  a  conspicuous  type  of  the  amphidetic 
ligament ;  Teilina  and  Venus  ex- 
emplify  the  opisthodetic  arrange- 
ment.  In  many  bivalves  a 
lozenge-shaped  cardinal  area  ex- 
tends amphidetically  between  the 
beaks,  while  the  ligament  is  wholly 
posterior,  being  visible  as  an 
oblique  triangulär  space,  with  its 
apex  at  the  umbonal  point  and 
its  base  at  the  hinge  line,  as  in 
Pteria.  Nearly  every  stage  in 
the  recession  of  the  ligament  can 

,  ,  1     <•  ^1  .       1   i  Homomya  calciformis  Ag.     Lower  Oolite ;  near  Bayeux. 

be  ODServed,  irom  truly  central  tO       WltU  well-preserved  extemal,  opisthodetic  Ugament.     2/3. 

posterior,  in  Lima  and  its  allies. 

The  most  perfected  type  of  ligament  is  that  which  may  be  compared  to  a 
cylinder  split  on  one  side,  and  attached  by  the  severed  edges,  one  edge  to 
each  valve.  This  type  is  known  as  parivincular  (Tellina,  Cardium) ;  its  long 
axis  corresponds  with  the  axis  of  motion  or  vertical  plane  between  the  valves, 
and  in  position  it  is  usually  opisthodetic.  Another  form  is  like  a  more  or 
less  flattened  cord  extending  from  one  umbo  to  the  other  {SpondyluSj  Liina), 
with  its  long  axis  transverse  to  the  plane  of  the  valve  margins  and  the  axis 
of  motion.  This  is  called  alivincular ;  it  may  be  central  or  posterior  to  the 
beaks,  but,  unless  very  short,  is  usually  associated  with  an  amphidetic  area. 
Lastly,  a  third  form  must  be  noted  which  consists  of  a  reduplication  of  the 
alivincular  type  at  intervals  upon  the  area  (Perna,  Area,  Fossula),  either 
amphidetically  or  upon  the  posterior  limb  of  the  cardinal  margin.  This  is 
designated  as  multivincular,  and  is  developed  out  of  the  alivincular  type. 

In  some  forms  with  a  rigid  hinge  and  internal  resilium,  the  ligament  may 
degenerate  into  its  archaic  epidermic  character,  as  in  some  species  of  Spondylus. 
It  is  impossible  to  draw  a  sharp  line  between  these  and  similar  forms  in  which 
the  ligament  is  not  quite  reduced  to  the  State  of  epidermis,  as  in  some  species 
of  Ostrea.  The  cardinal  area  above  referred  to  is  in  part  the  morphological 
equivalent  of  the  lunule  of  teleodont  Pelecypods.  In  general,  when  the 
ligament  has  become  opisthodetic,  the  remnant  of  the  area  in  front  of  the 
beaks  forms  the  lunule  and  may  be  called  prosodetic.  The  amphidetic  area 
is  an  archaic  feature  which  has  been  lost  by  the  more  specialised  types  of 
modern  bivalves,  and  its  gradual  disappearance  may  be  traced  in  various 
Prionodont  genera. 

The  Separation  of  the  ligament  and  resilium  has  been  described  as  due  to 
mechanical  causes.  In  those  cases  where  the  resilium  becomes  submerged 
between  the  valves,  the  area  of  attachment  of  its  ends  in  thin-shelled  forms  is 
more  or  less  thickened  and  assumes  a  spoon-like  form  projecting  from  the 
hinge-plate,  termed  the  chondrophore  or  resiliifer ;  this  is  often  reinforced  by  a 
special  prop  or  buttress  called  the  clavicle.  It  has  been  suggested  by  Neumayr 
that  part  of  the  armature  of  the  hinge,  in  the  shape  of  teeth,  is  due  to  deposits 
made  parallel  to  or  induced  by  the  presence  of  the  chondrophore  and  resilium. 


436  MOLLUSCA  phylum  vi 

There  is  some  reason  to  think  that  the  presence  of  the  resilium  in  Pecten 
and  Spondylus  may  be  connected  with  those  changes  of  the  auricular  crura 
which  lead  to  the  assumption  of  dental  functions  by  the  latter.  But  it  is  well 
known  that  submergence  of  the  resilium  occurs  independently  in  many  unre- 
lated  groups  of  bivalves ;  and  it  is  probable  most  of  them  were  previously 
dentiferous  and  still  retain  their  teeth,  although  more  or  less  modified  or 
displaced,  while  the  edentulous  gen  era  seldom  show  any  teeth  which  appear 
to  owe  their  existence  solely  to  the  presence  of  a  chondrophore.  The  nearest 
approach  to  a  hinge  composed  of  dental  laminae  of  such  an  origin  is  found  in 
Placuna,  Placenta  and  Placunanomia,  together  with  the  Spondylidae  already 
mentioned. 

Classification. — The  class  Pelecypoda,  which  comprises  about  5000  recent 
and  twice  as  many  fossil  species,  appears  to  be  divisible  into  three  ordinal 
groups :  Prionodesmacea,  Anomalodesmacea  and  Teleodesmacea ;  of  which  the 
third  represents  the  most  perfected  and  developed  (though  not  always  the 
most  specialised)  modern  type  of  bivalve.  There  seems  little  reason  to  doubt 
that  all  these  Orders  are  descended  frora  a  Prionodesmatic  radical  or  prototype, 
and  that  for  various  reasons  the  first  and  second  retain  more  evident  traces  of 
this  origin  than  the  third. 

For  convenience  of  comparison,  the  characteristics  of  these  Orders  will  be 
stated  here. 

Prionodesmacea. — Pelecypods  having  the  lobes  of  the  mantle  generally  separated,  or, 
when  caught  together,  with  imperfectly  developed  siphons ;  the  soft  parts  in  general 
diversely  specialised  for  particular  environments  ;  the  shell  strueture  nacreous  and  prismatic, 
rarely  porcellanous  ;  the  dorsal  area  amphidetic  or  obscure,  rarely  divided  into  lunule  and 
escutcheon,  and  when  so  divided,  having  an  amphidetic  liganient ;  ligament  variable,  rarely 
opisthodetic  ;  nepionic  stage  usually  Avith  a  taxodont  provinculum  ;  permanent  armature  of 
the  hinge  characterised  by  a  repetition  of  similar  teeth  upon  the  hinge  line,  or  by  amorphous 
schizodont  dentition  ;  habits  active,  sessile  or  nestling,  not  burrowing ;  monoecious  or 
dioecious. 

This  group,  originating  with  the  earliest  forms,  has  retained  many  archaic 
features  through  immense  periods  of  geological  time,  although  occasionally  developing 
remarkable  and  persistent  specialisations.  Notwithstanding  most  of  its  subdivisions 
have  arrived  at  a  notable  degree  of  distinctiveness,  intermediate  forms  of  ancient  date 
connect  them  all,  more  or  less  effectively,  with  the  parent  stem. 

Anomalodesmacea. — Pelecypods  having  the  mantle  lobes  more  or  less  completely  united, 
leaving  two  siphonal,  a  pedal,  and  sometimes  a  fourth  opening  between  them  ;  siphons  well 
developed,  always  at  the  posterior  end  of  the  body  ;  two  subequal  adductor  muscles  ;  the 
shell  strueture  nacreous  and  cellulo  -  crystalline,  rarely  with  a  prismatic  layer  ;  the  area 
amphidetic  or  obscure,  rarely  distinctly  divided  ;  the  ligament  usually  opisthodetic,  generally 
associated  with  a  separate  resilium,  chondrophores  and  lithodesma  ;  valves  generally  un- 
equal,  the  dorsal  margin  without  a  distinct  hinge  plate,  armature  of  the  hinge  feeble,  often 
obsolete  or  absent  ;  rarely  with  lateral  laminae  "orwell-developed  dental  processes  ;  usually 
burrowing,  hermaphrodite,  and  marine. 

This  group  is  intimately  related  to  many  of  the  Palaeoconcha,  except  as  regards 
the  presence  of  a  pallial  sinus.  It  retains  many  archaic  features,  and  includes  several 
of  the  most  specialised  modern  forms.  Through  the  Anatinacea  it  approximates  the 
Myacean  Teleodesmacea.  It  is  peculiar  in  the  possession  of  a  lithodesma,  and  in  the 
strueture  of  its  gills  and  hinge.  The  forms  with  a  reticulate  gill  have  it  of  a  different 
type  from  the  reticulate  gills  of  the  other  Orders ;  those  which  retain  a  modified 
foliobranch  gill  have  it  different  from  the  foliobranch  gill  of  Prion odesmacean  groups. 
There  are  no  forms  with  a  filibranchiate  gill,  or  with  a  typically  fully  developed 
reticulate  gill. 


CLASs  I  PELECYPODA  437 

Teleodesmacea.  — Pelecypods  witlj  reticulate  gills,  the  vontricle  of  the  heart  embracing 
tlic  rectum  ;  having  the  maiitle  lobes  more  or  less  connected  and  u.sually  possessing  dcveloped 
siplions  ;  the  adductors  practicaily  e(|ual ;  the  shell  structure  cellulo-crystalline  (porcellanous) 
or  obscurely  prismatic,  never  nacreous  ;  the  dorsal  area,  when  present,  always  prosodetic  or 
divided  into  lunule  and  escutcheon ;  ligament  opisthodetic,  with  or  without  separate 
resilium  ;  without'  a  lithodesraa,  rarely  with  externa!  accessory  shelly  pieces  ;  nepionic  stage 
usually  without  a  taxodont  provinculum  ;  permanent  armature  of  the  hinge  characterised  by 
tlie  Separation  of  the  hinge  teeth  into  distinct  cardinals  and  laterals  ;  the  posterior  laterals, 
when  present,  placed  behind  the  ligament ;  the  animals  active  or  nestling,  sometimes  sessile, 
but  rarely  sedentary  burrowers,  rarely  inequivalve,  usually  possessing  a  hinge  plate  and  a 
pallial  sinus  ;  sexes  usually  separate. 

It  is  doubtfiü  if  this  groiip  is  represented  in  tlie  Paleozoic  rocks,  especially  below 
the  Carboniferous,  thoiigli  genera  beloiiging  to  it  are  foresliadowed  by  some  of  the 
Palaeoconclis.  Altbough  most  of  the  Teleodonts  live  embedded  in  the  surface  of  the 
sea-bottom,  they  retain  their  ability  to  migrate,  and  only  a  few  extremely  specialised 
forms  inhabit  permanent  burrows  of  their  own  constriiction.  They  are  sometimes 
commensal  in  the  burrows  of  other  animals.  Similarly,  few  of  them  fix  themselves 
permanently  by  a  byssus,  although  often  byssiferous,  especially  when  young.  With 
the  exception  of  a  few  specialised  forms  they  possess  a  pair  of  direct  and  reflected 
branchial  laminae  on  each  side  of  the  body,  frequently  united  behind  the  foot,  forming 
an  anal  Chamber  ;  the  two  sets  on  one  side  usually  of  unequal  size,  and  of  the  reticulate 
type.  None  are  known  with  typically  foliobranch  or  filibranch  gills,  although  some 
abyssal  forms  have  archaic  sub-foliobranchiate  etenidia. 

There  remains  a  small  group  of  fossils,  difficult  to  refer  to  a  place  in  the  System, 
yet  characterised  by  several  features  in  common ;  these  have  been  named  by  Neumayr 
Palaeoconcha,  and  are  defined  by  him  as  follows  : — 

Palaeoconcha.— Prototypic  Pelecypods,  with  thin  shells,  a  simple  or  obscure  pallial  line, 
sub-equal  adductor  scars  placed  high  in  the  valves  ;  dorsal  area  absent  or  amphidetie  ;  liga- 
ment external,  variable;  hinge  margin  edentulous  or  with  polymorphous  teeth  form«d  by 
modifications  of  the  margin  and  not  set  upon  a  hinge  plate. 

While  the  forms  included  here  are  not  always  actually  the  most  ancient,  yet  in 
their  modifications  they  indicate  clearly  the  origin  of  many  subsequently  developed 
structures  found  in  Pelecypods  of  a  more  modern  type  ;  and  owing  to  their  undifferen- 
tiated  polymorphic  character  are  difiicult  to  assign  a  place  in  any  Classification  based 
on  more  highly  developed  forms.  There  is  little  doubt  that  some  of  these  show  taxo- 
dont affinities,  and  others  recall  PJioladomya  ;  but  the  final  discussion  of  these  puzzling 
forms  awaits  greater  knowledge  of  them  and  other  early  bivalves.  It  is  to  be  under- 
stood  that  the  places  assigned  them  in  the  present  systematic  arrangement  must  be 
more  or  less  provisional.      Neumayr  included  in  this  group  the  following  families  : — 

Vlastidae.  Praecardiidae.  Solenopsidae. 

CardioUdae.  Silurinidae.  Grammysiidae. 

Antipleuridae.  Protomyidae  (including  possibly  Posidonomyidae. 

Lunulicardndae.  the  Recent  Solemya).  Daonellidae. 

The  pelagic  Planktomya  henseni,  recently  described  by  Simroth,  presents  many  of 
the  characteristics  of  the  Palaeoconchs.  The  posterior  cardinal  margin  is  denticulate, 
the  ligament  internal,  and  the  gills  are  represented  by  a  single  lateral  plate  parallel 
with  the  longer  axis  of  the  shell  on  each  side  ;  a  type  elsewhere  only  known  in  con- 
nection  with  the  younger  stages  of  Scioheretia. 


438  MOLLUSCA  phylüm  vi 

Order  1.     PRIONODBSMACEA  DalL 

Section  A.     Palaeoconcha  p.p.  Neumayr.i 
Family  1.     Solemyacidae. 

Shell  soleniform,  equivalve,  low-heaJced,  edentulous,  gaping,  with  the  anterior  end 
longer  and  the  epidermis  conspicuous,  exceeding  the  valves  ;  area  obscure  or  none ;  Ligament 
amphidetic,  parivincular,  usually  internal  posteriorly ;  mantle  lohes  united  ventrally, 
attached  in  front  to  the  periostracum  and  valves  hy  a  hroad  surface,  leaving  no  distinct 
pallial  line ;  a  single  posterior  siphonal  and  anterior  pedal  foramen  in  the  mantle ; 
adductors  sub-equal,  with  a  thickened  ray  in  front  of  the  posterior  scar ;  animal  dioecious, 
marine,  hurrowing.     Devonian  to  Recent. 

Solemya  Lam.  Carboniferoiis  to  Recent,  rare  in  all  horizoiis.  Janeia  King, 
shorter  and  less  inequivalve,  may  include  most  of  the  Paleozoic  species  hitherto 
referred  to  Solemya.  Glinopistha  Meek  and  Worthen,  from  the  Carboniferous,  is  also 
allied,  and  Dystactella  Hall,  is  nnited  with  it  by  Zittel.  Phthonia  Hall,  from  the 
Devonian,  is  placed  here  by  Ulrich.  Ächarax  Dali,  Mesozoic  to  Recent,  has  a  purely 
external  ligament  and  no  clavicle. 

Family  2.     Solenopsidae  Neumayr. 

Shell  thin,  elongate,  equivalve,  with  very  anterior  heaks  ;  the  hinge  edentulous,  ligament 
parivincular,  external ;  pallial  line  not  sinuated ;  a  ridge  or  groove  radiating  from  the 
beak  to  the  lower  posterior  angle  of  the  valves.      Marine.     Devonian  to  Trias. 

Sanguinolites  M'Coy.      Elongate,  obliquely  truncate  behind ;    beaks  low,  sculp- 

ture  of  concentric  or  broken  lines,  an- 
terior adductor  scar  buttressed  by  a 
ridge.     Carboniferous. 

Promacrus     and     Prothyris     Meek. 
Pj,.  649  Carboniferous, 

Solenopsis  pelagica  Goldf.     Devonian  ;  Bifel  District.  Ärcomyopsis      Sandb.  Somewhat 

curved,  with  prominent  beaks ;  obliquely 
truncate  behind;  posterior  area  radially,  the  rest  of  the  surface  concentrically 
sculptured.     Devonian. 

Solenopsis  M'Coy  (Fig.  649).  Very  long,  scabbard-shaped,  smooth  ;  anteriorly 
Short  and  rounded,  gaping  behind.      Devonian  to  Trias. 

Family  3.     Vlastidae  Neumayr. 

Shell  thin,  very  inequivalve,  beaks  elevated,  hinge  line  edentulous,  arehed,  meeting  at  an 
obtuse  angle  beneath  the  beaks,  leaving  a  dorsal  opening  ;  surface  smooth  or  concentrically 
striate. 

The  two  genera  Vlasta  and  Dux  (Vevoda)  Barrande,  from  the  Silurian  of  Bohemia 
(Etage  E  2),  constitute  this  family. 

Family  4.     Grammysiidae  Fischer. 

Shell  thin,  equivalve,  oval  or  elongate,  with  the  beaks  sub-central  to  anterior ;  hinge 
edentulous,  sometimes  thickened.  Ligament  parivincular,  external;  imllial  line  not 
sinuate  ;  surface  smooth  or  concentrically  sculptured.     Silurian  to  Carboniferous. 

^  [The  terms  Palaeoconcha,  Taxodonta,  Schizodonta,  etc.,  preceded  by  Roman  numei-als,  are 
retained  here  merely  as  convenient  descriptive  ai)pellations,  and  are  in  nowise  to  be  regarded  as 
possessing  systematic  values.j 


CLASS  I 


PELECYPODA 


439 


Grammysia  Vern.  (Sphenoynya  Hall)  (Fig.  650).  Shell  elongate-ovate,  concen- 
trically  sculptured,  witli  a  deej)  luniüe  ;  cardinal  niargin  thickened,  edentulous ; 
siirface  with  several  radial 
grooves.  Silurian  and  De- 
voiiian.  Protomya  Hall  ih! 
similar  l)ut  without  the 
grooves. 

Leptodomus  M'Coy,  Sil- 
urian ;  Elymella,  Glossites^ 
Euthydesma,  Paleanatina 

and       (?)    Tellinopsis       Hall  ; 
Devonian. 

Gardiomorpha      Koninck.  "  ^'■"  '''''^" 

C^^Tn^      iiiflaforl      hoaVc    olrv^r^cf    Grmnmysia  hamükmeni<is  Vem.     Spirifer  Sandstone  (Lower  Devonian) ; 
UVai,^  mnatea,    OeaKS    almost  Lahnstein,  Nassau  (after  Sandberger). 

anterior,      cons2:)icuous,      ad- 

jacent,  prosogyrous ;  hinge  line  thin,  arched.     Silurian  and  Carboniferous. 

Isoculia  M'Coy.  Like  the  preceding,  but  with  coarse  concentric  sculpture, 
Carboniferous. 

Other  Carboniferous  genera  are  Broeckia  Koninck  ;  Ghaenomya  Meek  ;  Sedgwickia 
M'Coy ;  and  Edmondia  Koninck.  The  last  is  like  Gardiomorpha  but  gapes  in  front, 
with  a  narrow  ridge  below  the  beaks. 

The  Cambrian  FordiUa  Barrande,  earliest  of  bivalves  if  a  Mollusc,  very  likely  belongs 
to  the  bivalved  Crustaceans  near  Estheria.  It  is  minute,  oval,  somewhat  arcuate,  and  eon- 
centrically  striated.     Lower  Cambrian  ;  New  York  and  Massachusetts. 

Another  bivalved  shell,  regarded  by  some  authors  as  a  Pelecypod,  Modioloides  priscus 
Walcott,  from  the  Lower  Cambrian  of  eastern  New  York,  is  probably  also  of  Crustacean 
affinities.  Pizzaroa,  Tunaria  and  Bistramia  Hoek,  from' the  Silurian  of  Bolivia,  are  probably 
byssal  bivalves. 

Family  5.     Cardiolidae  Neumayr. 

Shell  equivalve,  inflated,  ohliquely  ovate,  with  prominent  heaks,  and  edentulous  hinge  ; 
sculpture  offen  radial,  or  sometiraes  of  concentric  ridges  lohich  may  he  confined  to  the 
beaks.     Silurian  and  Devonian. 

Gardiola  Brod.  (Fig.  651);  Gloria  Barrande;  Eopteria 
(?  Euchasma)  Billings  ;  from  the  Ordovician,  may  also  belong  here. 

Family  6,     Antipleuridae  Neumayr. 

Shell  very  inequivalve  without  gape  below  the  beaks ;  hinge 
obscurely  taxodont,  with  an  amphidetic  area  and  predominantly 
radial  sculpture.     Silurian. 

Äntipleura,  Dualina  and  Dalila  of  Barrande. 

Fig.  651. 

Cardiola  cornucopiae 
Goldf.  Devonian ;  Ebers- 
reuth,  Fichtelgebirge,  i/^. 


Family  7.     Praecardiidae  Neumayr. 

Shell   equivalve  with    taxodont    dentition  and   usually  strong 
radial  sculpture.     Silurian  and  Devonian. 

This  family  contains  the  following  genera  of  Barrande  from  the  Silurian  of 
Bohemia :  Praecardium,  Paracardium,  Puella,  Pentata,  Buchiola  {Glyptocardia  Hall), 
Praelucina,  Regina,  Praelima  ;  to  which  Neumayr  adds  Pleurodonta  Conrath,  and 
Pararca  Hall.  It  is  possible  that  Silurina  Barrande,  regarded  by  Neumayr  as  the 
type  of  a  distinct  family,  may  also  be  included.  It  is  distinguished  by  its  feebler 
structure  and  a  dorsal  radial  groove  near  the  cardinal  border. 


440 


MOLLUSCA 


PHYLUM  VI 


Section  B.     Taxodonta  Neiimayr  (emeiid.). 
Superfamily  1.     NUCULACEA. 

Shell  of  variable  form,  closed  ventrally,  equivalve,  with  a  smooth  epidermis  ;  nacreous 
or  porcellanous  with  tuhuliferous  external  prismatic  layer ;  area  ohscure,  or  none,  when 
present  divided  into  lunule  and  escutcheon ;  ligament  variable,  amphidetic ;  gills  folio- 
branchiate;     both    adductors    present    and    sub-equal ;   foot    grooved    and    reptary,   not 


erous ;  marine. 


Family  8.     Otenodontidae  Dali. 

Shell  nuculiform,  with  the  teeth  in  a  continuous  arched  series ;  no  area ;  ligament 
external,  alivincular,  without  an  external  resilium ;  pallial  line  simple.  Ordovician 
and  Siluriaii. 

Gtenodonta  Salter  {Tellinomya  Hall  p.p.)  (Fig.  652).  Oval,  smooth  or  con- 
centrically  striate,  in  the  later  horizons  sometimes  with  Leda-like 
ornamentation.     Ordovician  and  Siluriaii. 

Gucullella  (M'Coy)  Fischer.     Ovate,  thin-shelled,  with  a  straighter 
hinge  line  and  a  radial  buttress  to  the  anterior  addnctor.     Silurian. 

p^^^  g^2  Family  9.     Nuculidae  Adams.i 

ctenodontapectun-  Shell  Compact,  closed,  with  the  teeth  in  two  series  meetinq  below  the 

culoidesHall.  Ordo-  ,  ,77777  ,777 

vician ;  Cincinnati,    umbones,  separated  by  a  chondrophore ;  area  represented  by  an  obscure 

^^^^^^   lunule  and  escutcheon;  no  ligament,  but  a  wholly  internal,  amphidetic, 

alivincular  resilium ;    internal  layer  of  shell  nacreous ;  mantle   lobes 

free,  without  siphons ;  pallial  line  simple.     Silurian  to  Recent. 

Nucula  Lam.  {Nuculana  Link)  (Fig.  653).  Oval  or  triangulär,  concentrically  or 
reticulately  sculptured.      Silurian  to  Recent.      Re-  a 

presented  by  over  200  fossil  and  half  as  many  Recent 
species. 

Acila  Adams.   With  divaricate  sculpture.    Lower 
Cretaceous  to  Recent. 


Ohio.       2/j 
Hall). 


Family  10,      Ledidae  Adams.i 

Shell  as  in  the  Nuculidae,  but  elongated  with  the 
ligament  variable,  the  resilium  sometimes  external  or 
absent,  the  internal  shell  layer  sub-nacreous  or  por- 
cellanous, the  ends  of   the  shell  partly  gaping ;    the 

mantle  lobes  more  or  less  united 

elongate  siphons 

to  Recent. 


Fi(i.  053. 
A,    Nucula    strigilata    Goldf.      Upper 
Trias;    St.    Cassian,    Tyrol.     i/i-    B,    N. 
nucleus  Linii.  Miocene ;  Grussbach,  near 
Vionna.     i/j. 

ivith  complete,  sometimes 
pallial  line  usually  sinuated.     Ordovician 


Gleidophorus  Hall  {Adranaria  Mun.-Chalm.)  (Fig. 
654).  Shell  rostrate,  the  anterior  side  sh orter,  with  an 
internal  radial  buttress.     Ordovician  and  Devonian. 

Gytherodon  Hall.  Silurian  and  Devonian.  (?)  Redonia 
Rouault ;  Gadomia  Tromelin  ;  Palaeoneilo  Hall ;  Anuscula 
Barr. ;  and  Myoplusia  Neiimayr.      Silurian. 


Fio.  654. 

CkidopTiorus  cuUratus  Sandb. 
Internal  monld  from  Lower  Devon- 
ian ;  Niederlahnstein,  Nassau,  i/j. 

1   Verrül,  A.  E.,  and  Bush,  K.  ./.,  Revision  of  the  genera  of  Ledidae  and  Nuculidae. 
Joura.  Sei.  [4],  1897,  vol.  iii. 


Am  er. 


CLASS  I 


PELECYPODA 


441 


Leda  Scliuiu.  (Figs.  655,  656).     Shell  rostrate,  elongate,  often  keeled,  conceiitri- 
cally  Stria te  ;  liiiige  as  in  Nucida  ;  pallial  siiius  siiiall.     Siluriaii  to  Receiit. 


•  Fio.  655. 

Leda  rostrata 
(Lam.).  Middle  Jura; 
Milhaud,    Aveyron. 

Vi. 


Fio.  650. 

Leda  desJiayesiana  Duch. 
Oligocene ;  Rupelmonde, 
Belgium.     i/j. 


Yoldia  arctica  Gray. 
Pleistocene ;  Bohus- 
län,  Sweden.    i/i- 


Fig.  658. 

NucuUna  ovalis 
(Wood).  Miocene; 
Forchtciiau,  near 
Vienna. 


Yoldia  Moller  (Fig.  657).  •  Sliell  tliin,  wide,  and  niore  or  less  gaping  beliind, 
hinge  as  in  Nucula.     Cretaceous  to  Recent. 

Nuc'idina  ^^Ov\).  (Fig.  658).  Nuculiform,  hinge  teethfew  and  discrepant ;  with 
large  lateral  tootli  and  external  ligament.      Tertiary  and  Recent. 

Malletia  Desm.  and  Tindaria  Bell.  Yoldiform  and  nnculiforni  respectively,  but 
without  internal  chondrophore.     Tertiary  and  Recent. 


Superfamily  2.     ARCACEA  Deshayes. 

Shell  of  varied  form,  usually  with  a  pilose  epidermis,  porcellanous,  with  tiihiiliferous 
non-prismatic  external  layer ;  area  typically  amphidetic,  ligament  external,  ali-  or 
multivincular ;  gills  filibranchiate,  with  the  filaments  usually  reflected ;  mantle  lohes 
free,  without  siphons,  the  pallial  line  simple;  foot  variable,  deeply  grooved,  hyssogenous ; 
marine  or  fluviatile. 

Family  11.     Parallelodontidae  Dali. 

Shell  arciform,  with  the  posterior  hinge  teeth  elongated,  tending  to  he  parallel  to  the 
hinge  margin ;  ligament  multivincular.     Carhoniferous  to  Recent. 

The  ancient  forms  of  this  group  appear  to  connect 
with  the  Pteriacea  through  Fterinea,  and  with  Area 
through  Cucullaea.  The  Recent  forms,  which  froni 
their  shell  characters  have  been  referred  to  Maerodon, 
are  all  small  and  probahly  should  be  referred  to  the 
Arcidae.  The  relationship  of  this  family  to  the 
Arcidae  is  very  iutimate  but  not  exclusive. 

Parallelodon  Meek  {Maerodon  Lycett)  (Fig. 
659).  Shell  elongate,  snl)-qnadrate,  with  ani- 
phidetic  area,  and 
prominent,  rather 
anterior  beaks. 
Anterior  teeth 
transverse  or  flex- 
uous,  posterior  long 
and  parallel  to  the 
hinge  line.  Devon- 
ian  to  Tertiary ; 
maximum  in  Goal 
Measures. 

Grammatodon 


Parallelodon  hirsonensi.i  Morris  and 
Lyc.  Great  Oolite ;  Minchinlianii)ton, 
England.     Vi- 


Fio.  6ö0. 
CmnUaea  hersilüi  d'Orb.     Oxford ian 
St.  Reniy,  Ardennes.     Vi- 


Vieil 


442  MOLLUSCA  phylüm  vi 

Meek  and  Worthen,  and  Nemodon  Conrad,  are  allied.  Garhonarca  Meek  and  Wortlien. 
Beaks  inflated,  curved,  angiüar  beliind ;  hinge  margin  curved,  witli  two  oblique 
teetli.     Carboniferous, 

Gucullaea  Lani.  (Fig.  660).  Sliell  inflated,  trapezoidal ;  liinge  teetli  in  tlie  centre 
of  tlie  hinge  short,  transverse  or  oblique,  the  terminal  teeth  on  each  side  longer,  sub- 
parallel to  the  hinge  line  ;  posterior  adductor  usually  supported  by  a  radial  elevated 
lamina  or  buttress.     Jura  to  Recent  ;  maximum  in  Mesozoic. 

Gucullaria  Desh.,  of  the  Eocene,  and  Idonearca  Conrad,  are  closely  allied. 

Family  12.     Oyrtodontidae  Ulrich. 

Shell  equivalve,  short,  usually  heavy,  convex  and  earthy,  without  persistent  epidermis, 
area  small,  ligament  parivincular  (.?) ;  hinge  teeth  transitional  between  the  Parallelodon 
and  Dysodont  type;  adductor  scars  suh-equal,  the  posterior  larger  hut  less  impressed. 
Ordovician  and  Silurian. 

These  forms  are  evidentlj"  intermediate  in  character.  They  recall  Limopsis  among  later 
types,  are  nearly  related  to  the  Parallelodontidae,  but  have  not  the  multivincular  ligament  ; 
the  hinge  has  Dysodont  elements,  but  the  ditference  of  texture  and  epiderniis  stand  in  the 
way  of  assimilating  them  with  Mytilacea. 

Gyrtodonta  Bill.  (Gypricardites  p.p.  Conrad ;  Palearca  Hall).  Shell  rounded, 
moderately  ventricose,  with  rather  tumid,  incurved,  anterior  beaks  ;  area  narrow  and 
obscure  ;  cardinal  teeth  two  to  four,  obliquely  curved  or  horizontal ;  lateral  teetli  near 
the  posterior  eiid  of  the  hinge  elongate,  strong,  curved  or  oblique  ;  pallial  line  simple. 
Anterior  adductor  set  on  the  wall  of  the  valve.     Ordovician  and  Silurian. 

Vanuxemia  Bill.  Beaks  more  nearly  terminal,  anterior  adductor  scar  excavated 
out  of  the  hinge  plate.      Ordovician. 

Whitella  and  Tschyrodonta  Ulrich  ;  Matheria  Billings.      Ordovician  and  Silurian. 

Family  13.     Limopsidae  Dali. 

Shell  pectunculoid,  equivalve  or  nearly  so;  the  ligament  alivincular,  partly 
immer sed,  its  socket  approaching  a  chondrophore  ;  area  small ;  foot  long,  narrow,  grooved, 
byssiferous  ;  otherwise  as  in  Ärcidae.      Trias  to  Recent. 

These  forms  precede  the  typical  Area  and  have  a  special  facies  of  their  own.  The  two 
dental  series  of  the  hinge  are  often  discrepant  in  character  or  direction,  recalling  the 
Parallelodontidae. 

Limopsis  Sasso  (Fig.  661).     Small,  rounded  or  oval,  recalling  Glycimeris,  except 
for  the  alivincular  ligament.      Trias  to  Recent. 

Trinacria  Mayer  {Trigonocoelia  Nyst).  Like  Limopsis,  but  tri- 
angulär, with  the  posterior  slope  keeled.  Eocene.  Gnisma  Mayer, 
from  the  Eocene,  appears  to  be  related. 

Family  14.     Arcidae  Dali. 

Shell  trapezoidal  or  rounded,  with  the  posterior  side  longer;   ligament 

Fig.  661.  usually  multivincular ;  hinge  typically  taxodont,  with  the  teeth  in  two 

Limopsis  aurita   ^'^'^'^^o^i'  series,  meeting  helow  the   heaks,  and   approximately  vertical  to 

pL^Sza^^iT^"^'    ^^^  inargin  of   the  valve;  foot    stout,  short,  deeply  grooved.     Jura    to 

Recent. 

Most  of  the  Paleozoic  ^rca-like  forms  are  probably  Parallelodontidae,  and  the  typical 
Areas  are  preceded  by  Pectunculoid  forms.  The  convergence  of  the  types  of  Arcacea  as  \ve 
recede  in  geological  time  is  very  marked,  and  their  relations  to  the  Nueulacea  are  evident  in 
spite  of  the  later  developed  ditferences. 


CLASS  I 


PELECYPODA 


443 


Area  Lani.  (type  A.  noae  Liiin.).  Shell  trapezoid,  eqiiivalve,  with  a  wide  amphi- 
detic  area,  distant  conspiciioiis  Ijeaks,  and  radial  sciilpture  ;  a  wide  l)yssal  gape  ;  a 
long,  straiglit,  transversely  dentale  hinge  line,  with  niany  sniall  siniilar  teeth. 
Tertiary  and  Recent.  Used  in  the  wider  sense  to  include  all  the  groups  of  Arcidae, 
there  are  some  200  living  and  300  to  400  fossil  speeies. 

Subgenera :    Barhatia   Gray  (Fig.   662)  ;    Scapharca,   Noetia,    Anadara   (Fig.    663)  and 
Argina  Gray  ;  Scaphula  Benson  (fresh-water),  etc. 

Isoarca  Münst.  (Fig.  664).  Shell  smooth,  inflated  ;  beaks  füll,  incurved  ;  hinge 
line  with  rather  aniorphous  dentition.      Upper  Jura  and  Lower  Cretaceous.     • 


Fig.  662. 

Area  (Barhatia)  harhata  Linn.    Miocene  ; 
Grund,  iiear  Vienna.     i/j. 


Fig.  603. 

Area  {Anadara)  diluvii  Lam. 
Pliocene  ;  Siena. 


Pio.  664. 

Area  (Isoarca)  cordi- 
formis  Ziet.  Upper  Jura ; 
Nattheim,  Würtemberg. 

V,. 


Glycimeris  Da  Costa  {Pectunculus  Lam. ;  Axinea  Poli)  (Fig.  665).     Rounded  and 
almost  symmetrical.     Basal  margin  dentate ;  area  as  in  Area,  but  shorter  ;  ligament 


Fig.  665. 
Glycimeris  dbovatus  (Lam.).     Oligocene  ;  Weinheim,  near  Alzey,  Hesse.     Vi- 

multivincular ;  teeth  oblique,  in  an  arched  series,  interrupted  during  growth  by  the 
subsidence  of  the  areal  margin.      Cretaceous  to  Recent ;  maximum  in  Miocene. 


Section  C.     Schizodonta  Steinmann  (emend.). 

Superfamily  3.     PTERIACEA  Dali. 

Shells  of  varied  form,  frequently  alate,  with  a  nacreous  or  suh-nacreous  inner  and 
prismatic  outer  layer ;  the  epidermis  seldom  conspieuous ;  area  amphidetic ;  ligament 
variable,  usually  not  parivincular ;  gills  filihranchiate  or  reticulate,  usually  reßected ; 
mantle  lobes  free,  without  siphons ;  pallial  line  simple;  the  anterior  adductor  smaller. 


444 


MOLLUSCA 


PHYLUM  VI 


or  frequently  obsolete  in  the  adult,  thoiujh  iiresent  in  the  young ;  generally  hyssiferous ; 
hinge  schizodont  or  edentulous.  The  young  sometimes  showing  a  distinct  nepionic  stage. 
Marine. 


Family  15.     Pterineidae  Dali. 

Shell  pteriiform,  Malaie,  dirayarian,  the  anterior  adductor  smaller ;  inequivalve,  very 
inequilateral ;  dentition  ohscure ;  ligament  amphidetic,  external,  multivincular  (?) ;  the 
hyssus  passing  through  a  notch  in  the  smaller  valve.     Ordovician  to  Devonian. 

In  Pterinea  and  its  allies  we  have  the  first  indications  of  divergence  of  what  ultimately 
becanie  taxodont  and  schizodont  dentition.  From  this  assemblage,  as  indicated  by  Jackson, 
a  large  proportion  of  the  Prionodesmacea  have  diverged  in  various  directions.  It  is  probable 
that  from  tliis  source  the  filibranchiate  Taxodonts  have  sprung,  rather  than  directly  from  the 
foliobranchs. 

Rhomhopteria  Jackson  (Fig.  666).     Posterior  wiiig  separated  from  tlie  body  of  the 

A  B 


Fio.  666. 

Rh(ynibopteria  mira 
(Barr.).  Silurian  (E) ; 
Prague,  Bohemia(after 
Jackson). 


Fio.  667. 

A,  Pterinea  laevis  Goldf.     Devonian  ;  Niederlahnstein,  Nassau.     Interior  of  left 

valve,  Vi-     -B,  P-  Uneata  Goldf.    Same  locality  ;  external  view. 


valve  by  a  shallow  sinus  ;  anterior  wing  short ;  teeth  obscure,  the  posterior  elongated. 
Silurian. 

Pterinea  Goldf.  (Fig.  667).  Left  valve  convex,  riglit  valve  flat ;  hinge  plate  long, 
broad,  auriculate  before  and  behind ;  area  amphidetic,  grooved  ;  ligament  parivin- 
cular  (?) ;  anterior  teeth  obscure,  transverse  ;  the  posterior  elongate,  nearly  parallel  to 
the  Cardinal  margin,  depressed  behind.  Posterior  adductor  scar  large,  the  anterior 
small  but  strong,  inserted  below  the  anterior  wing.  Ordovician  to  Carboniferous ; 
particularly  abundant  in  the  Devonian  of  Europe  and  America. 

Äctinodesma  Sandb.  {Glijptodesma,  Ectenodesma  Hall;  Dolichopteron  Maurer). 
Like  Pterinea,  but  with  the  wings  elongated  and  pointed.     Devonian. 

Leptodesma  Hall ;  Kochia  Frech  {Onychia  Sandb.;  Loxopteria  Frech).    Devonian. 


Family  16.     Lunulicardiidae  Fischer. 


Usually  equivalve,  triangulär  shells  with  terminal  healcs,  from  which  a  sharp  ridge 
runs  toward  the  lower  margin,  hounding  a  flattened  area.  Hinge  margin  straight,  long. 
Internal  characters  unknown.     Silurian  and  Devonian. 

Lunulicardium  Münst.  Anterior  side  with  a  byssal  sinus.  Silurian  and 
Devonian.     L.  semistriatum  Münst. 

Patrocardium  Fischer  {Hemicardium  Barr.,  non  Cuvier).  Without  byssal  sinus. 
Silurian. 

Additional  genera  :  Amita  {Spanila,  TetinJca),  Mila,  Tenha,  Bahinha  {Matercula) 
Barrande.     Silurian. 


CLASS  I 


PELECYPODA 


445 


Family  17.     Ambonychiidae  Miller. 

Shell  mytiliform,  with  no  anterior  wing,  the  anterior  adductor  obsolete;  equivalve, 
very  inequilateral ;  dentition  obsolete  or  schizo- 
dont ;  licjament  external,^  multivincular  (?) ; 
byssus  passing  through  a  narrow  gape  hetween 
the  valves  which  are  otherwise  closed.  Ordo- 
vician  to  Devonian. 

The  typical  Amhonychia,  according  to  Ulrich, 
is  edentulous  ;  the  fornis  ordinarily  i)assing  under 
that  name  being  now  referred  to  Byssonychia,  In 
this  group  the  byssus  does  not  pass  through  a 
notch  in  one  of  the  valves. 

The  Ambonychiidae  include  the  typical  meni- 
bers  of  Amhonychia,  JByssopteria  and  Amphicoelia 
Hall  ;  Opisthoptera  {Megaptera)  Meek  ;  Anomalo- 

dontamm^v,  Byssonychia  and  AUonychia  UMch,         a,  Byssonychia  sp.    Cincinnati    Group;  Cin- 
and  their  allies.  cinnati,  Ohio.     Interior  of  right  valve.     V,  (after 

Miller).    B,  B.  radiata  (Hall).     Same  locality. 

Byssonychia    Ulrich    {big.     668).     Hinge 
with  several  small  cardinal  and  two  or  three  slender  lateral  teeth ;   area  striated  ; 
byssal    opening  present    in  tlie   upper  half  of    the   anterior  face ;    otherwise   as    in 
Ämbonychia. 

Silurian.     Mytilarca  and  Plethomytilus  Hall.     Devonian. 
{Cyrtodontopsis    Frech.).      Thicker    shelled,  with   heavier   and 
Devonian. 
Edentulous,  concentrically  sculptured.     Ordovician. 


Paleocardia  Hall. 
Gosseletia    Barrois 
more  numerous  teeth. 
Glionychia  Ulrich. 


Pinna  pyramidalis  Münst. 
Quader  Sandstein ;  Schan- 
dau,  near  Dresden.     1/3. 


Fig.  670. 

Pinnigena  scehachi  Böhm.     Upper  Jura  ;  Kelheim,  Bavaria. 
External  and  internal  views,  1/3  natural  size. 


446 


MOLLUSCA 


PHYLUM  VI 


Family  18.     Pinnidae  Meek. 

Shell  mytüiform^  not  alate,  dimijarian,  the  anterior  adductor  smaller ;  equivalve, 
truncate  and  wholly  open  behind ;  edentulous ;  area  linear ;  ligament  parivincular^ 
internal ;    shell    structure   coarsely   prismatic,  with    a   thin,  partial,  nacreous    lininfj ; 

ferous.     Devonian  to  Eecent. 


Palaeopinna  Hall.     Devonian  ;  North  America. 

Aviculopinna  Meek.  A  very  small  wing  in  front  of  the  beaks.  Carboniferous 
and  Permian. 

Pinna  Linn.  (Fig.  669).  Shell  thin,  with  a  long  hinge  line  and  emarginate 
nacreous  layer;  valves  carinate,  the  carina  sulcate,  section  triangulär.  Jura  to 
Recent.  • 

Pinnigena  Sauss.  (Trichites  Plott)  (Fig.  670).  Muscular  imj)ression  very  large ; 
prismatic  layer  extremely  thick  ;  sculpture  divaricate.     Jura  and  Cretaceous. 

Atrina  Gray.  Shell  with  broad  adductor  scars  ;  short  hinge  line,  no  sulcus  or 
carina,  the  nacreous  layer  entire.     Carboniferous  to  Recent. 

Gyrtopinna  Mörch.     Jura  to  Recent. 


Family  19.     Oonocardiidae  Neumayr. 

Shell  sub-trigonal,  anteriorly  truncate  and  gaping,  the  margins  of  the  gape  frequently 
produced  into  a  tuhe-like  rostrum  and  sharply  serrate  helow,  the  posterior  end  usually 

alate,  the  wing  divided  internally  hy  a  longitudinal  ridge; 
dimyarian,  the  anterior  adductor  scars  smaller  ;  equivalve 
more  or  less  gaping  behind;  schizodont,  with  a  single 
anterior  lateral,  and  an  obscure  or  obsolete  cardinal 
tubercle ;  area  ill-defined,  amphidetic ;  ligament  external, 
parivincular ;  shell  structure  cancellate,  or  built  up  of 
hollow  prisms  resembling  those  of  Pinna,  but  not  solid ; 
valves  thick,  internally  marginate  ;  byssifeous  {?)  ;  marine, 
conocardium  almforme  Sowerby.    Ordovician  to  Carboniferous. 

Lower  Carboniferous  ;  Tournay,  Bel- 

gium.    i/i-  This  group  inchides  Conocardium  Bronn  {Pleurorhynchus 

Phill.)  (Fig.  671),  and  Mhipidocardium  Fischer.  It  is  ex- 
tremely isolated,  and  comprises  some  fifty  species.  These  remarkable  shells  have  been 
referred  by  most  paleontologists  to  the  Cardiacea,  with  which  they  liave  no  conncction  what- 
ever  except  analogy  of  form  with  a  few  aberrant  Cardiidae. 

Family  20.     Pernidae  Zittel. 
Shell  sub-mytiliform,  with  a  broad  posterior  wing;  monomyarian,  the  anterior  adductor 


Fig.  671. 


Fio.  672. 
Ä,  Gervülia  aviculoides  Sow.     Oxfordian  ;  Dives,  Calvados.     B,  G.  linearis  Bouvignier.     Hinge. 

absent  in  the  adult ;  inequivalve,  teeth  irregulär  or  absent,  with  a  serial  multivincular 
ligament ;  byssiferous,  with  a  moderate  gape,  or  none.      Permian  to  Recent. 


CLASS  I 


PELECYPODA 


447 


This  family  differs  from  the  Pteriidae  chiefly  by  its  multivinciilar  ligament  in  tlie  adult 
State.     It  linds  its  niaximum  development  in  the  Jura  and  Cretaceous. 

Bahewellia  King.      Small,  obliqiiely  eloii-^Mlud,  alate  Ijehind,  tliree  to  four  den- 
ticulations  iinder  the  beaks.      Pernnan. 

Gervülia  Defr.   (Fig.    672).     Posterior   wing    obscure,   hinge    plate    thick,   beaks 
terminal,  pointed,  with  obscure  dental  ridges  siib-parallel 
to  the  long  axis  of  the  valve.     Trias  to  Eocene, 

Subgenus  Hoernesia  Laube  (Fig.  673).  With  a  streng  tooth 
under  the  beak  and  subtaxodont  denticulations  on  the  pos- 
terior Cardinal  border.     Trias. 


Fig.  G73. 


Odontoperna    Frech.      Quadrate    with    two    to    three 
oblique  dental  folds  below  the  beaks.     Trias. 

Pedalion   Solander  (Jsognomon  Klein  ;    Perna  Brug.  ; 
Mulletia    Fisch.)    (Fig.    674).      Equi valve,    subquadrate, 
with  terminal  beaks,  an  anterior  byssal  notch,  edentulous    Muschelkalk  ^"würzburg,  Bavaria. 
hinge,  and  numerous  ligamentary  grooves.   Trias  to  Recent. 

Alpine  Trias.      Pernostrea  Munier- Chalmas.     Jura. 

Inoceramus  Sowerby  (Gatillus 
Brong.  ;  Haploscapha  Conr.  ;  Neo- 
catülus  Fisch.)  (Fig.  675).    Rounded 


Fio.  674. 


Pedalion  soldanii  (Desh.).     Oligocene  ;  Waldböckelheim, 
near  Kreuznach,  Prussia.     1/2. 


hwceramus  cHpsi  Mant.  Upper  Cretaceous 
Gosau,  Austria.     1/2  natural  size. 


with  concentric  sculpture  ;  prominent,  rather  anterior  beaks, 
and  edentulous  hinge  bearing  numerous  small  ligamentary  pits. 
Jura,  and  especially  the  upper  and  middle  Cretaceous. 

Subgenera ;  Actinoceramus  Meek  (Fig.  676),  with  radial  sculp- 
ture.;  Volviceramus  Stol.  ;  Anopaea  Eichw.  ;  Haenleinia  Böhm. 

Grenatula  Lam.     Thin-shelled,  elongate,  smooth.     Jura  (?), 

Pliocene  and  Recent. 

Family  21.     Pteriidae  Meek. 

Shell  aviculoid,  Malaie,  monomyarian,  inequivalve,  with  an 
alivincular  ligament ;  the  hjssus  issuing  hy  a  notch  in  the  smaller 
valve ;  the  yonng  dimyarian,  the  anterior  adductor  disappearing 
with  age.     Silurian  to  Recent. 

Pteria  Scopol!  (Avicula  Brug.)  (Fig.  677).  Cardinal 
border  in  the  young  with  pseudocardinal  and  lateral  teeth,  becoming  more  or  less 
obscure  with  growth  ;  shell  thin,  oblique.      Devonian  to  Recent. 


A  et  inoceramus  sulcatus 
Park.  Gault;  Perte  du 
Rhone,  Ain.     i/j. 


448 


MOLLUSCA 


PHYLÜM  VI 


Sub^^enera:  Adinopteria,  Leiopteria,  VertiLmnia  Hall.  Devonian.  Pteronites  WQoy. 
Devonian  and  Carboniferous.  ?  Rittotia  de  Kon.  Carboniferous.  Oxytoma  Meek  (Fig.  6/8). 
Trias  to  Cretaceous.     Mcleagrina  Lam.     Jura  to  Recent. 

Limoptera  Hall  (Monopteria   Meek  ;    Myalinodonta,  Parops 
wing  reduced,  posterior  large.     Devonian  and  Carboniferous. 


ffililert).     Anterior 


Fig.  677. 
Pteria  contorta 
(Porti.).      Rhae- 
tic;    Kössen, 
Tyrol. 


Fici.  678. 

Pteria  (Oxytoma)  costata  Sow.     Great  Oolite 
Luc,  Calvados. 


Fig.  679. 


Pseudomonotis  ecliinata  Sow.     Cornbrash 
(Oolite) ;  Button,  England. 


Pteroperna  Morris  and  Lycett.     Middle  Jura. 

Pseudomonotis  Beyr.  {Eumicrotis  Meek)  (Fig.  679).      Left  valve  fiat,  anterior  wing 
not  developed  or  minute.     Devonian  to  Cretaceous, 

Gassianella  Beyr.  (Fig.  680).      Left  valve  inflated  with  prominent  incurved  beak  ; 


Fig.  680. 

Gassianella  gryphaeata  (Münst.).     Upper  Trias 
St,  Cassian,  Tyrol. 


Fig.  681. 
Monotis     salinaria     (Schloth.).      Red 


Alpenkalk      (Norian) ; 
Bavaria.     -j^. 


Berchtesgaden, 


the  right  Hat  or  concave,  witliout  byssal  sinus ;  teeth  small  as  in  Pteria,  but  more 
numerous  ;  area  ampliidetic,  wide.     Trias. 

Monotis  Bronn  (Fig.  681).  Equivalve,  compressed,  radially  striate,  witli  low,  sub- 
central beaks ;  anterior  wing  indistinct,  rounded  ;  posterior  wing  short,  truncate  or 
oblique.     Trias. 

Halohia    Bronn  {Daonella    Mojs.)  (Fig.  682).     Equivalve  like  Monotis,  but  the 


Halohia  {Daonella)  lommeli  Wissm.      Lower  Keuper  (Norian) ; 
Wen  gen,  South  Tyrol. 


Fig.  683. 

Posidonomya  hecheri  Bronn.    Culm  Measures : 
Herborn,  Nassau,    i/^. 


anterior  wing  only  represented  by  a  smooth  non-projecting  area  (Halohia),  or  botli 
wings  absent  (Daonella).     Abundant  in  the  Trias. 


CLASS  T 


PELECYPODA 


449 


Posldiniininjd  V>v(nn\  {Ahlacomnja  Stciiini.)  (Fig.  683).  EciuivaTve,  lliiii,  (•(Mii]ir<->('d, 
coiicentiically  wavcd  ;  liiiigc  inargiii  sti;iigli1,  cdciilulous  ;  valves  not  auriculate  ;  beaks 
sub-ceiitral,  not  conspicuous.  Sihuian  lo  Jul■a^i<i(•.  Ovcr  fifty  species  are  known  ; 
very  jjrofiise  in  tlie  Jura-Trias,  sometinies  forniing  massive  beds. 

Malleus  Lam. ;  (?)  Pltilohrya  Carpenter  ;  (?)  Hochstetteria  Velain.     Recent. 


heaks 


Aucella  mosqucnsis  Keys.     Upper 
Jura ;  Moscow,  Russia. 


Family  22.     Myalinidae    Frech. 

Shell  obliquely  ovate,  widened  hehind,  sometinies  lüith  a  small  anterior  ear 
anterior   or   terminal  ;    hinge   edentulous,  straight ;    area 
amphidetic,    longitudinally    grooved ;     ligament    parivin- 
cular  (?)     Adductor  scars  suh-equal ;  hyssal  notch  distinct. 
Silurian  to  Jura. 

Myalina  de  Kon.  Shell  thick,  ol)lique,  with  deep 
adductor  scars  anteriorly  under  the  terminal  beaks. 
Silurian  and  Devonian. 

Hoplomytilus  Sandb.;  Myalinoptera  Frech ;  Ptycho- 
desma,  Mytilops  and  Modiella  Hall.  Devonian.  Leio- 
myalina  Frech  ;  Aphanaia,  Posidoniella  de  Kon.  ;  Liebea 
Waagen  ;  Atomodesma  Beyr.     Carboniferous. 

Pergamidea    Bitt.       Thick-shelled,  equivalve,  inflated  ;  anterior  auricle    distinct, 
sharply  truncated  ;  hinge  margin  notch ed  below  the  beak.     Trias  of  Asia  Minor. 

Mysidia  Bitt.     Anterior  ear  reduced.      Trias. 

Aucella    Keys.    (Fig.    684).     Tliin,    inequivalve,    inflated,    small,    concentrically 
waved,    sometinies    with    radial  Striae.     Left  valve  larger,  arcuate,  witli  very  small 
anterior    ear ;    riglit   valve   flatter    and   smaller.     Area    short, 
striated,  with  a  ligamental  sulcus  below  the  beak.     Upper  Jura 
and  Cretaceous  ;  distribution  world  wide. 

Family  23.     Vulsellidae    Adams. ^ 

Shell  Ostreiform,  not  alate,  monomyarian,  edentulous,  inequi- 
valve, with  an  alivincular  ligament ;  hyssus  wanting ;  otherwise 
as  in  the  Pteriidae.  Tertiary  to  Recent.  A  degraded  type 
which  has  become  specialised  through  commensalism  with 
Sponges. 

Vulsella  Lam.  (Fig.  685).  Shell  vertically  produced, 
irregulär,  edentulous,  with  a  triangulär  chondrophore  for  the 
Eocene  to  Recent. 

Vulsellina  de  Raine.     Eocene.     (?)  Ghalmasia  Stol.     Creta- 

s.      (?  suh  Ostreidae.) 


Superfamily   4.     OSTRACEA   Goldfuss. 

Shell    degenerate,    sessile,    inequivalve,    generally    edentulous, 

wings  obsolete;   with  a  sub-nacreous  or  porcellanous  inner  and 

,■    2tt    prismatic  outer  layer ;  epidermis  inconspicuous  ;  area  amphidetic, 

Miiiich',    ligament  alivincular ;   foot  and    byssus  ahsent ;    valves  usually 

close-fitting ;  mantle  lobes  free,  without  siphons. 


ligament 


Fin.   685. 

Vllhrll,,      r,,;/hni 

E!,'ypt.     -'/o. 


Family  24.     Ostreidae    Lamank. 
Shell   distorted    by    early  adherence    to    other  objects ;    monomyarian,    the    anterior 


l)nvrill,\  //..   Ktudes  sur  Irs  Vulsc'llidc's.      Ami.  Fiilroiit..  1907,  vol.  ii. 


VOL.   1 


2  G 


450 


MOLLUSCA 


PHYLUM  YI 


adductor  ahsent ;  edentulous,    or    luith  ohscure  schizodont    dentition ;    dimijarian    when 
young  ;  the  foot  obsolete  or  ahsent  in  the  adidt.     Carboniferous  to  Recent. 

Ostrea  Linn.  (Fig.   686).     Shell  irregulär,  iiiequivalve,  and  witli  terminal  beaks, 


Fio.  686. 
Ostrea  digitalina  Dubois.     Miocene  ;  Vienna  Basin. 


Fio.  687. 

Alectryonia  (jregaria 
(Sow.).  Oxfordian  ; 
Dives,  Calvados. 


witb  radial  or  foliaceous  sculpture,  usually  discrepant  on  the  two  valves.  Some  species 
(0.  virginica^  titan,  gigantea,  etc.)  attain  a  very  large  size.     Carboniferous  to  Recent. 

Alectryonia  Fischer  (Dendrostrea  Swains  ;  Adinostreon  Bayle)  (Fig.  687).  Left 
valve  attached  to  roots  or  branches  by  clasping  shelly  processes  ;  botli  valves  with 
strong,  often  divaricate  folds  and  undulate  margins.  Trias  to  Recent ;  maximuni  in 
Jura  and  Cretaceous. 

Gryphaea  Lam.  {Pycnodonta  Fisch.;   Gryjjhaeostrea  Conr.)  (Figs.  688,  689).     Left 


Fig.  688. 

Gryphaea  arcuata  Lam. 
Lower  Lias ;  Pf  obren,  near 
Donfiuescbingen,  Baden. 


Fig.  689. 

Gryphaea  vesicularis  Lam.     Wlxite  Clialk 
Isle  of  Rügen. 


valve  strongly  arched,  with  incurved  beak,  sessile  when  young,  later  free  ;  right  valve 
flat  and  opercular.     Lias  to  Tertiary  ;  chiefly  Mesozoic. 

Exogyra  Say  {Amphidonta  Fischer  ;  Geratostreon,  Aetostreon^  Ehynchostreon  Bayle) 
(Figä.  690,  691).  Resembliug  Gryphaea,  but  the  valves  more  equal,  hinge  with  an 
obscure  tooth,  beaks  of  both  valves  niore  or  less  spiral,  the  pit  for  the  ligament  narrow. 
Upper  Jura  and  Cretaceous. 


CLASR  I 


PELECYPODA 


451 


Terquemia  Täte  {Garpenteria  DesL).     Shell  witli  a   marginal  ridge,  f 
right  valve  ;  left  valve  fiatter,  free.     Trias  and  Lias. 


sessile  by  the 


Fig.  690. 

Exogyra  columha  Lam.     Greensand  (Ceno- 
manian) ;  Regensburg,  Bavaria. 


Fig.  691. 


Exogyra  flahelkitoi  (Goldfuss).     Cenomanian 
Saint  Paul  Cloister,  Egypt. 


Family  25.     Eligmidae    Gill. 

Shell  thick,  suh-equivalve,  free  lohen  adult,  resemhling  Chalmasia  in  form,  anteriorly 
with  an  irregulär  pedal  gape  ;  edentulous,  monomyarian,  tüith  the  adductor  seated  on  the 
free  extremity  of  a  myophore  projecting  from  the  umhonal  cavity,  otherwise  like  the 
Ostreidae.     Upper  Jura. 

Eligmus  Desl.  If  the  cliaracters  of  this  genus  liave  been  correctly  interpreted,  it 
can  hardly  be  retained  in  tlie  Ostreidae.  Fiirther  investigation  of  tlie  genns  is 
desirable. 

Superfamily  5.     NAIADACEA  Menke. 

Shell  of  varied  form,  normally  equivalve  and  dimyarian ;  rarely  alate ;  shell 
suhstance  nacreous  and  prismatic,  loith  a  conspicuous  epidermis ;  area  ohsßure  er 
amphidetic ;  ligament  parivincular,  usually  opisthodetic  and  external ;  pallial  lobes 
usually  free,  except  for  an  anal  siphon,  the  pallial  line  simple;  foot  normally  long, 
compressed,  heeled ;  hyssus  obsolete  ;  young  usually  with  a  distinct  nepionic  stage  ;  Station 
usually  fluviatile  or  lacustrine. 

Family  26.     Oardiniidae    Zittel. 

Shell  equivalve,  closed,  with  feehle  concentric  sculpture  or  smooth  ;  dentition  schizodont 
or  ohscure ;  ligament  opisthodetic,  external ;  dimyarian,  adductor  scars  suh-equal,  pedal 
scar  feehle  or  invisihle  ;  Station  marine  or  hrackish  water.     Devonian  to  Trias. 

Ämnigenia  Hall.     Devonian  (Catskill)  of  North  America,  and  Rhenish  Priissia. 

Garhonicola  M'Coy  {Anthracosia  King)  (Fig.  692).  Shell  thin,  oblong  ;  hinge 
with  a  blimt  elongated  cardinal,  and  a  feeble  posterior  lateral  tooth  upon  a  thickened 
hinge  plate.  Common  in  the  Goal  Measures  and  estuarine  Permian  of  Rnssia,  also 
America  and  Africa. 

Naiadites  Dawson  {Anthracoptera  Salter).  Shell  modioliform,  obliquely  triangulär, 
Avitli  almost  terminal  beaks,  straight  hinge-line,  striated  hinge-plate,  and  superficially 
marked  with  flat  concentric  lamellae.     Goal  Measures ;  North  Amei-ica  and  Europe. 


452 


MOLLUSCA 


PHYLUM  VI 


Anthracomya  Salter ;  Asthenodonta  Whiteaves.  Goal  MeaBures.  Palaeomutela 
(Ohligodon)  and  Palaeanodonta  Anializky.     Brackisli  Perniiaii  marls  of  Europe, 

Anoplophora  Sandb.,  emend.  von  Koenen  (Uniona  Poldig)  (Fig.  693).  Eiglit  valve 
with  a  blunt  tliick  cardinal  tootli  fitting  into  a  .socket  in  tlie  opposite  valve.  Left 
valve  beside  tlie  socket  has  a  long  posterior  lateral  tootb.  Trias  (Lettenkoble).  A. 
donacina  Scblotli. ;  A.  leitica  (Quenst.). 


Anoplophora  lettica  (Quenstedt). 
Trias ;  Friedrichshall  (after  Al- 
berti). 

A 


Fig.  692. 


A,  Carhonicöla  carbonaria  (Goldfuss). 
Permian  ;  Niederstaufenbach,  near  Kusel, 
Rhenish  Bavaria.  B,  C.  Uttneri  (Ludw.). 
Goal  Measures  ;  Hannibalzeche,  near 
Bochiim,  Westphalia  (after  Ludwig). 


Fig.  694. 

Trigonodus  sandhergeri  Alberti. 
Trias  (Lettenkohle);  Zimmern, 
Würtemberg.  A,  Hinge,  from  a 
gutta-percha  cast  taken  from  a 
natural  mould.    7i,  Natural  mould. 

Vi- 


Trigonodus  Sandb.  (Fig.  694).  Cardinal  tootli  strong,  triangulär,  sometimes 
divided,  short,  oblique,  anterior ;  two  elongate  laterals  in  the  left  valve,  and  one 
lateral  in  the  right  valve.  Trias  ;  especially  common  in  the  Lettenkoble  dolomite 
and  the  Eaibl  beds. 

Heminajas  Neumayr.     Trias.     H.  (Myophoria)  fissidentata  Wöhrmann. 

Pachycardia  Hauer.  Oblong  or  trigonal,  concentrically  striate  or  smooth  ;  beaks 
nearly  terminal,  curved,  adjacent,  with  a  lumule ;  anterior  end  inflated,  blunt; 
posterior  compressed  ;  two  strong  divergent  cardinal  teetli  in  each  valve,  the  anterior 
on  the  right  being  weaker  and  nearly  marginal ;  each  valve  has  also  a  long  posterior 
lateral  tooth.     Alpine  Trias. 

Gardinia  Agassiz  {Tlialassites  Quenst.)  (Fig.  695).     Oblong,  thick,  short  anteriorly, 


Fig.  695. 
Lower  Lias  ;  Ohrsleben,  near  Halberstadt,  Saxony. 


Cardinia  hyhrida  Sow. 

rounded.     Cardinal  teeth  weak  or  obsolete,  posterior  lateral  strong.     Lower  Lias,  and 
reported  also  from  the  Dogger. 

{TjNyassa  Hall.     Devonian.     (i)  Guerangeria  {Davousti)  (Ehl&ci.     Lower  Devonian. 


CLA.SS  I 


PELECYPODA 
Family  27.     Megalodontidae  Zittcl.' 


453 


>  Shells  equivalve,  sah-mytüiform,  closed,  witli  feehle  concentric  sculpture  or  none  ;  di- 

myarma,  with  amphidetic  area,  and  external  opisthodetic  ligament,  frequently  supported 
hy  nijmphae;  cardinal  teeth  strong,  usually  two  or  three,  ivith  a  posterior  lateral,  all 


Fig.  696. 
MigiiJniliiii  (Eumcijalodon)  cucullatus  Goldf. 
near  Cologne.     i/^. 


Devonian  ;  Pattrath, 


tri'iurti  i{\\'uUtiu).  lutenial 
niould.  Trias  dolomite ; 
Bleiberg,  Carinthia. 


Fio.  698. 
Megalodon  (Neomeij'ilniltiii)  fiilmheli  Stoppani.     Rhaetic  ;  Elbigenalp,  Tyrol  (after  Gümbel). 

heavy  and  amorphous ;  anterior  adductor  scars  distinct,  with  a  ivell-marked  myophoric 
ridfje  and  pedal  scar,  the  posterior  adductor  scars  frequently  hordered  hy  an  elevated 
crest.     Marine.     Silurian  to  Upper  Jura. 

These  Shells,  which  are  ofteii  very  ponderous,  sometimes  bear  a  remarkable  resemblance 
to  some  Recent  American  Uniones.  The  myophoric  ridge  is  common  to  very  distinct  bivalves 
of  many  unrelated  groups.  The  true  position  of  these  forms  cannot  be  regarded  as  positively 
üxed  as  yet.  Pachyrisma  is  thought  by  Böhm  to  be  genetically  related  to  Cardium,  and  the 
genus  Mcgalodon  niay  have  been  ancestral  to  primitive  Chamacea. 

Megalodon  Sow.  {Tauroceras  amd  Lycodes  Schafli.  ;  Conchodon  Stopp.)  (Figs.  696-698). 

^  Gümhel,  C.  W.,  Die  Dachsteinbivalven.  Sitzuiigsber.  Akad.  Wiss.  Wien,  1862,  vol.  xlv. — 
ITocnu's,  R.,  Materialen  zu  einer  Monographie  der  Gattung  Megalodus.  Denkschr.  Akad.  Wiss. 
Wien,  1880,  vol.  xl.  —  Böhm,  G.  Megalodon,  Pachyrisma  und  Diceras.  JSer.  Naturforsch. 
Gesellsch.  Freiburg,  1891,  vol.  vi. 


454 


MOLLUSCA 


PflYLUM  V 


Beaks  prosogyrous  ;  hinge  plate  veiy  broad  and  massive,  without  laterals  ;  tlie  two 
cardinal  teetli  separated  by  a  deep  socket ;  anterior  adductor  scar  small,  seniilunar, 
in  front  of  the  anterior  cardinal ;  posterior  scar  longer,  less  distinct,  sitiiated  on  an 
elevated  or  thickened  radial  ridge.  The  oldest  Devonian  species  (M.  cucullatus  Goldf.) 
has  amorphous  cardinals  and  a  sniooth  rounded  shell  (ßumegalodon).  The  Triassic 
species  sometimes  attain  a  large  size,  have  a  radial  posterior  ridge,  smooth  teeth,  and 
divided  right  posterior  cardinal  teeth  {Neomegalodon  Gümb.).  They  are  extraordinarily 
abundant  in  the  Dachstein  limestone  and  Hauptdolomite  of  the  Northern  Alps,  and 
are  also  plentiful  in  the  Raibl  and  Rhaetic  beds  of  the  Southern  Alps.^ 

Pachyrisma  Morr.  and  Lyc.  {Pachymegalodon  Gümb.).  Like  MegalodoUy  but  with 
a  larger  anterior  adductor  scar,  a  rounded  anterior  tooth  before  the  cardinals,  and  a 
strong  posterior  lateral.     Trias  to  Upper  Jura. 

Durga  Böhm.  ■  Like  Pachyrisma,  but  without  an  elevated  area  at  the  posterior 
adductor.     Lias. 

Protodiceras  Böhm.     Lias.     Dicerocardium  Stoppani.     Rhaetic. 

Megalomus  Hall.     Silurian  ;  North  America. 


Family  28.     Unionidae  Fleming. 

Shell  equivalve,  dimyarian,  typically  schizodont,  ivith  pseudocardinals  and  laterals 
if  dentiferous  ;  conspicuously  nacreous ;  beaks  usually  sculptured  ;  ligament  opisthodetic, 
external ;  lohes  of  the  mantle  generally  united  to  form  an  anal  siphon,  hut  the  functional 
hranchial  siphon  always  incomplete  helow ;  foot  compressed,  keeled,  large,  rarely  with  a 
feehle  hyssus ;  usually  dioecious ;  the  young  having  a  specialised  prodissoconch 
{glochidium)  and  a  distinct  nepionic  stage.     Fluviatile.     Trias  to  Recent. 

Typical  Uniones  make  their  appearance  in  the  Trias  of  Texas,  but  are  not  abundant  until 
the  Cretaceous  and  Tertiary.  The  origin  of  the  family  has  been  sought  in  the  Trigoniidae,^ 
which  have  a  very  similar  ontogeny  as  a  group  ;  in  Trigonodus  ^  and  related  forms  ;  and  by 
Pohlig  in  the  Triassic  Uniona.  An  older  view  recognises  the  Carboniferous  Anthracosia  and 
other  Cardiniidae  as  probable  ancestors.  The  weight  of  evidence  is  in  favour  of  the  latter, 
thougli  there  is  much  probability  that  each  of  these  groups  bears  a  certain  amount  of  relation- 
ship  to  the  present  family,  which  will  be  better  realised  when  niore  evidence  is  obtainable. 

Recent  studies  by  Simpson  and  Ortmann  of  the  anatomy  of  living  genera  of  Unionidae 
have  sliown  that  considerable  ditFerences  exist  as  regards  the  soft  parts,  more  especially  the 


Fig.  699. 
Unio  stachei  Neumayr.    Pliocene  (Congerian  stage) ;  Sibinj,  Sla venia,    p,  Adductor  ;  x,  Pedal  scar. 

marsupial  apparatus  (that  part  of  the  gills  which  contains  the  glochidia)  and  the  shape  of 
the  glochidia.  These  differences  permit  of  an  improved  System  of  Classification  for  the 
modern  forms,  but  as  the  shape  of  the  shell  is  not  at  all  correlated  with  the  natural  divisions 
indicated  by  the  structure  of  the  soft  parts,  it  is  impossible  to  apply  tliis  System  with 
certainty  to  fossil  Unionidae. 

Unio  Retzius  (Fig.  699).     This,  the  typical  genus,  originally  included  also  the  pearl 

^  Tausch,  L.  vo)i,_tJheT  Conchodus,  etc.     Abhandl.  geol.  Keichsanstalt,  1892,  vol.  xvi. 
2  JSTeumayr,  M.,  Über  die  Herkunft  der  Unioniden.     Sitzber.  Akad.  Wiss.  Wien,  1889,  xeviii. 
•^   Wöhrmann,  S.  von,  Über  die  systematische  Stellung  der  Trigoniden  und  die  Abstammung 
der  Nayaden.     Jahrb.  geol.  Reichsanst.,  1893,  vol.  xliii. 


CLASS  I  PELECYPODA  455 

müsse]  {My(c  tnargaritifera  Liiiii.),  in  which  tlie  posterior  luiiiiiiac  of  the  liinge  are 
obsolete.  It  sliows  in  the  niajority  of  species  aniorplious,  heavy,  radial,  pseudocardinal 
and  lateral  teetli  on  the  hinge  ;  the  sliell  is  variable  in  form  and  ornamentation,  some 
species  having  strongly  marked  sexual  difterences  in  the  shell.  Most  of  the  species 
are  peaiiy,  with  a  conspicuous  brown  or  greenish  periostracum  ;  the  anterior  adductor 
scars  are  high,  and  the  pedal  scars  conspicuous. 

Änodonta  Cuv.  Valves  thin,  and  armature  of  the  hinge  obsolete  ;  lives  in  still, 
muddy  water.     Tertiary  and  Recent. 

Margaritana  Schum.  The  pearl  mussei,  formerly  associated  with  Mya  and  Unio^  is 
anatomically  intermediate  Ijetween  the  Unionidae  and  Mutelidae.    Tertiary  and  Eecent. 

Family  29.     Mutelidae  Gray. 

Shell  resemhling  that  of  the  Unionidae,  without  pseudocardinals  and  laterals ; 
having,  when  dentiferous,  an  irregularly  taxodont  hinge  armature;  heahs  unsculptured ; 
mantle  lohes  generally  partly  closed ;  siphons  more  complete.  Nepionic  stage  {Jcnovm 
only  in  a  fev)  South  American  forms)  said  to  he  represented  by  a  Lasidium.  Cretaceous 
to  Recent. 

Spatha  Lea.  Elongated,  inequilateral,  with  a  short  edentulous  hinge.  Living  in 
Africa,  and  doubtfully  present  also  in  the  Upper  Cretaceous  of  Provence. 

Anodontites  Bruguiere  (Glaharis  Gray) ;  Leila  Gray  ;  Monocondylaea  and  Mycetopoda 
d'Orl).;  Mutela  Scopoli  {Iridina  Lam.);  and  Pleiodon  Conrad.  Recent.  Two 
subfamilies,  Mutelinae  and  Hyriinae,  are  recognised  by  Ortmann  on  the  basis  of 
structural  differences  in  the  soft  parts. 

Family  30.     Etheriidae  Lamarck. 

Shell  sessile,  irregularly  modified  by  adherence  to  other  bodies,  nacreous,  with  a 
tendency  to  cellularity  of  structure ;  edentulous;  ligament  amphidetic,  parivinculary 
deeply  sunken,  with  a  large  internal  resilium,  modified  by  the  distortion  of  the  valves  ; 
young  regulär,  equivalve,  dimyarian ;  the  adult  irregulär,  inequivalve,  and  either  (1) 
monomyarian,  or  (2)  with  a  very  degenerate  anterior  adductor,  or  (3)  with  sub-equal 
adductors.  Mantle  lobes  united  only  for  the  anal  siphon  ;  foot  degenerate  or  absent  in 
the  adult ;  young  hyssiferous ;  Station  ßuviatile.      Pleistocene  and  Recent. 

The  young  shell  of  Bartlätia  has  well-niarked  nymphae  and  internal  resilium.  The 
relationship  of  the  Naiadacea  to  Pteria  renders  the  remarkable  resemblance  of  the  adult 
Muelleria  to  Ostrea  less  surprising,  siiice  Ostrca  is  now  known  also  to  be  derived  from  the 
Pteriidae. 

Etheria  Lam.  Ostreiform,  attached  to  rocks  in  African  rivers.  Also  Pleistocene 
of  West  Africa. 

Muelleria  Ferussac  ;  Bartlettia  Adams.     Recent ;  South  American  rivers. 

Superfamily   6.     TRIGONIACEA   Bronn. 

Shell  equivalve,  inequilateral,  closed,  dimyarian,  not  alate ;  shell  suhstance  nacreous 
and  prismatic  ;  hinge  teeth  few,  sub-umbonal,  typically  schizodont ;  area  obscure  or  none  ; 
ligament  parivincular,  opisthodetic,  external ;  gills  filibranchiate ;  mantle  lobes  usually 
free,  but  modified  on  the  posterior  edges  to  form  functional  siphons  without  conjunctive 
partitions ;  pallial  line  usually  simple;  non-byssiferous,  though  possessing  an  obsolete 
byssal  apparatus ;  young  without  a  distinct  nepionic  stage  ;  dioecious  ;  marine. 

Family  31.     Lyrodesmidae  Ulrich. 

Shell  with  the  hinge  armature  radiating  fan-like  from  below  the  umbones  ;  teeth  five 
to  nine;  pallial  line  feebly  sinuate  or  simple.     Ordovician  and  Silurian. 

LyrodesmM  Conr.  {1  Actinodonta  Phil.).  Shell  oval,  cardinal  boixler  narrow,  wiili- 
out  ligamentary  area.      Ordovician  and  Silurian  ;  America  and  Europe. 


456 


MOLLUSCA 


PHYLÜM  VI 


,,  siuootli  ;  lateral  teetli  not  fliited 
Abiiiidaiit  111  the  Periniaii. 


Family  32.     Trigoniidae  Lamarck. 

Shell  with  few  hinge  teeth  (|),  the  mantle  lohes  lüholly  free,  hut  so  applied  to  each 
other  in  life  as  to  form  functional  siphons ;  pallial  line  simple.     Devoiiiaii  to  Receiit. 

Schizodus  King  (Fig.  700).     Ovate  or  quadrate, 
anterior  adductor  scar  witli  a  sniall  radial  buttress. 

MyophoriaBi-oiiii{Neoschizodus  ^^                             Gieb.)    (Figs.    701,    702). 

Smooth    or    radially    sculptured,  \^^        ^J         usually     with     a     strong 

radial   ridge  extending  from    the  ^^^^!^^^           uinbones     back  ward     and 

down  ward   to   the  basal  margin  ;  ^^^r                   the  sciüpture  on  the  areas 
AB 


Fig.  700. 

Schizod7is  obscürus  Sow.  Zeclistcdn;  Nieder- 
rodenbach,  near  Hanau.  A,  Internal  niould, 
Vi.     B,  Hinge,  i/i  (after  King). 


Myophoria  lasvigata 
(Alberti).  Schaumkalk ; 
Rüdersdorf,  near  B(!r- 
lin.     Vi- 


M  yitpliAyrUt      decustiata     Münst. 
Upper  Trias  ;  St.  Cassian,  Tyrol. 

A,  Bxterior  of  riglit  valve,   Vi' 

B,  Enlarged  vlew  of  hinge. 


Trigonia  navis  Lam.     Lower  Brown  Jura  ; 
Gundershofen,  Alsace.     Vi- 


Trigonia  dandala  Park.     Middle  Crcitaceous 
(Hervien) ;  Meule  de  Bracquegnies,  Belgium.  i/i. 


Fig.  705. 

Trigonia     costata     Sow, 
Middle  Jura ;  Würteißterg. 


Fig.  706. 
Trigonia  cf.  aliformis  Park.     Senoni; 
Vaels,  near  Aix-la-Chapelle.     i/i- 


Fig.  707. 

Trigonia  pectinaia 
Lamarck.  Recent;Aus- 
tralia.     Hinge,  l/i. 


CLASS  1 


PELECYPODA 


457 


thus  Heparated  usiially  discrepaiit.  Beaks  inesogyrate,  lateral  teetli  fluted,  inuscular 
scars  biittressed  by  feel)le  ridges.     Abuiidaiit  in  the  Trias. 

Siil)genus  :  Myoijhorio'psis  Wüliriii.  {Astartopsis  Wölir.).      Trias. 

Trigonia  Brug.  (Figs.  703-707).  Surface  sculptured  witli  iiodulose  ribs  or  rows  of 
pustiiles,  tlie  2>osterior  dorsal  area  usiially  discrepaiit  witli  tlie  rest.  Beaks  opistho- 
gyrous,  nearly  teriuinal ;  teetli  striated  ;  addiictor  scars  stroiig,  with  biittressiiig  ridges. 
Lias  to  Recent ;  abuiidant  in  Jura  and  Cretaceous,  very  sparse  in  later  horizons. 


Section  D.     Isodonta  Fischer. 


Superfamily  7.     PECTINACEA  Reeve. 


Shell  usually  inequivalve,  ßabelliform,  more  or  less  auriculate,  and  monomyarian ; 
shell  structure  sub-nacreous,  corrugated,  and  rarely  prismatic^  occasionally  tahular ;  area, 
when  present,  amphidetic ;  ligament  amphidetic,  alivincular  ;  gills  filibranchiate,  free,  the 
filaments  loith  or  withoiU  a  reßected  limb ;  mantle  lobes  free,  without  siphons,  usually  with 
ocelli,  papillae,  or  other  tactile  prominences  along  the  margin,  and  with  an  inner  pro- 
jecting  lamina  (curtain)  near  the  margin,  at  right  angles  to  the  plane  of  the  valves  ;  pallial 
line  simple ;  foot  small,  usually  sub-cylindrical,  grooved,  and  byssiferous ;  usually  mon- 
oecious  :  marine. 


Family  33.     Pectinidae  Lamarck. 

Shell  inequivalve,   inequilateral,  auriculate,  usually   closed, 
free;  area  amphidetic  or  obscure ;  ligam.ent  obsolete  extern- 
ally,  the  immersed  portion  forming  an  internal  resilium, 
provinculum  taxodont  in  the  very  young,  obsolete  later,  the 
crural  teeth  feeble  or  not  developed.     Silurian  to  Recent. 

Aviculopecten  M'Coy  (Fig.  708).  Shell  pectiniforni, 
radially  sculptured.  Hinge  margin  long,  feebly  auriculate; 
ligament  in  numerous  shallow  grooves  radiating  to  the 
amphidetic  margin  of  the  area.    Silurian  to  Carboniferous. 

Subgeiiera :    Ficrineo2)ecten  Hall 
2)ecten  Hall).     Devonian. 


monomyarian,   us 


ually 


Orhipecten  Frech  {Lyrio- 


Fio.  708. 


Ä  viculopecten 
Goal  Measures 
phalia. 


]Hipyraccus  Sow. 
Werden,    West- 


Grenipecten  Hall  (Pernopecten  Winch.).  Like  Aviculo- 
pecten, but  with  a  taxodont  hinge.      Carboniferous. 

The  preceding  genera  lead  up  to  the  prototypes  of  Pteriidae 
as  a  radical  for  the  present  family. 

Pecten  Müller  {Vola  Mörch  ;  Janira  Schum. ;  Neithea 
Drouet)  (Fig.  709).  Shell  nearly  equikteral,  very  inequi- 
valve, sub-symmetrical,  with  well -developed,  sub-equal 
ears ;  one  valve  (usually  the  right)  more  convex  than  the 
other ;  interior  of  the  valves  not  lirate ;  hinge  with  a 
strong  medial  internal  resilium,  on  each  side  of  which 
interlocking  crural  ridges  and  grooves  radiate  in  the 
adult ;  Ijyssal  notcli  inconspicuous.     Cretaceous  to  Recent. 

The  above  diagnosis  is  of  the  subgenus  Pecten  s.  s.  In  a 
Wide  sense  all  the  species  of  Pecten  are  free  and  auriculate,  and 
without  internal  lirae.  Thoy  have  been  divided  into  an  ex- 
cessive  number  of  sections  aecording  to  the  superficial  shell  characters,  but  these  rarely 
niarch  with  anatomical  differences,  and  cannot  properly  be  regarded  as  of  generic  value.  The 
most  familiär  of  the  groups  thus  named  are  as  follows  : — 

Chlamys  Holten  {Pallium  Schum.;  Decadopedcn  Rüpp.)  (Figs.  710,  711).     Shell  radially 


l'ecten  quinquecostata  Sow.    Ceno- 
manian ;  Rouen.     i/i- 


458 


MOLLUSCA 


PHYLÜM  VI 


sculptured,  nearly  equivalve,  with  small,   iinequal  ears,  and  deep  byssal  notch  with  well- 
developed  ctenolium.     Trias  to  Recent. 

CamjJtonectes  Ag.    (Fig.    712).      Shell  small,   tliin,    nearly  smootli,    with  fine  divergent 
striation  radiating  from  a  median  line.     Jura  to  Recent. 


Fio.  710. 

Peden  (Clüamys)  suUextorius 
Goldf.  Coral-Rag ;  Nattheim. 


Fio.  711. 

Peden  (Chlamys)  varius  Linn. 
Pliocene ;  Rhodes. 


Fk;.  712. 


Fig.  713. 

Peden  (Ento- 

liwrn)  cornutus 

Peden  {Camptonedes)  Uns    Qnenst.  Upper 

Sovv.     Middle  Jura  ;  Baiin,    Jura  ;    Hohen- 

near  Cracow.     i/^.  zolleni.     i/i. 


Entoliutn  Meek  (Fig.  713).  Smooth,  thin,  with  sub-equal  ears  diverging  at  a  sharp  angle 
above  the  beaks  ;  byssal  notch  obsolete.     Carboniferous  to  Cretaceous. 

Pseudamusium  Adams.  Shell  small,  thin,  glassy ;  the  posterior  ear  obsolete,  byssal  notch 
distinct.     Cretaceous  to.  Recent.     Syncyclonema  Meek  is  scarcely  different. 

Amusium  Bollen  (Fig.   714).     Shell  with  raised  radial  riblets  interiially ;    ex- 


FiG.  714. 
Ämuslwin  cristatus  (Bronn).     Miocene    Baden,  near  Vienna.    l/i. 


Fig.  715. 

Hinnites  ahjcdus  (Phill.). 
Middle  Jura ;  Baiin,  near 
Cracow.     i/i. 


ternally  smootb.  or  delicately  sculptured  ;  valves  large,  flattish,  with  sub-equal  ears  ; 
byssal  notch  inconspicuous  or  absent.     Lias  to  Eecent. 

Subgenus  :  Propeamusium  Greg.  Small,  thin,  abyssal^,  often  with  relatively  conspicuous 
sculpture,  usually  discrepant  on  the  valves.     Tertiary  and  Recent. 

Hinnites  Defr.  (Fig.  715).  Shell  free  and  Pectiniform  when  young,  later  adherent 
to  other  objects  and  more  or  less  distorted.     Trias  to  Eecent. 

Pedum  Brug.  Shell  with  an  alivincular  ligament  in  an  oj)en  groove  and  area  like 
that  of  Spondylus  in  the  adult ;  the  young  like  Ghlamys.     Eecent ;  sessile  on  corals. 


Family  34.     Spondylidae  Fleming. 

Shell  inequivalve,  nearly  equilateral,  closed,  'pectiniform,  obscurely  auriculate,  mono- 
myarian;  sessile;  area  amphidetic,7nuch  larger  on  the  attached  valve;  ligament  alivincular^ 
rmlium  more  or  less  suhmerged ;  byssus  obsolete;  hinge  with  a  taxodont  provinculum, 


CLASS  I 


PELECYPODA 


459 


hecoming  obsolete  in  the  adiUt  and  re-placed  hy  the  tyjncally  isodont  develo^ment  of  the 

crura  ;  otherivise  as  in  the  Pectinidae.  Trias  to  Recent. 

Plicatula  Lam.  {Harpax  Park.)  (Fig.  716).  Shell 
conipressed,  with  coarse  radial,  often  divaricate 
ribbiiig,  a  small  area,  and  long  shallow  crenulate 
crural  teeth,  diverging  at  a  sharp  angle.  Trias  to 
Recent ;  inaximum  in  Jura  and  Cretaceous. 

Spondijlus  Linn.  (Figs.  717,  718).  Sliell  inflated, 
with   radial,   often    spiny  or    foliaceous  sculpture ; 


Fio,  716. 

Plicatula  2)ectinoides  Lara.     Middle  Lias  ; 
Nancy,  France. 


Fio.  717. 

Spondylus  spinosus  (Sow.).     Plänerkalk  ; 
Strehlen,  near  Dresden.    2/3. 


Fio.  718. 

Sptondylus  tenuisplna  Sandb.    Oligocene  ;  Waldböckelheim,  near 
Kreuznach,  Prussia.    1/1. 


Jura 


attached  valve  with  a  conspicuous  area  ;  crural  teeth  heavy,  short,  smooth. 
to  Recent  ;  maximuin  from  the  Tertiary  onward. 

(?)  Pachijpteria  de  Koninck.     Carboniferous.     P.  nobilissima  (de  Koninck).      Pro- 
spondylus  Zinimerin.     Pennian  and  Trias.     Philippiella  Waagen.     Alpine  Trias. 


Family  35.     Dimyidae  Dali. 

Shell  inequivalve,  irregulär,  closed,  auricles  not  differentiated,  Ostreiform,  dimyarian, 
shell  suhstance  suh-nacreous  and 


fihrous ;  area  amphidetic,  ohscure  ;  liga- 
ment  obsolete,  resilium  alivincular,  in- 
ternal; hinge  armature  taxodont,  obsolete; 
crural  development  feeble;  gills  fili- 
branchiate,  the  direct  filaments  not 
reflected;  foot  and  byssus  absent ;  an- 
terior adductor  distinct,  small ;  posterior 
duplex,  larger.     Trias  to  Recent. 

Dimya    Rouault  {Dimyodon    Mun.- 
Chalni.)  (Fig.  719).     The  Recent  forms  inhabit  deep  water. 


Fio.  719, 


Dimya  deshayesiana  Rouanlt.     Eocene  ;  Pyrenees.     Inner 
and  outer  views  of  right  valve,  3/2  (alter  Rouault). 


Family  36.     Limidae    d'Orbigny. 

Shell  equivalve,  auriculate,  gaping,  Pectiniform,  monomyarian ;  shell  substance 
fibrous,  with  minute  tubules,  not  nacreous  or  prismatic  ;  hinge  edentulous,  or  with  traces 
of  taxodont  armature;   area  amphidetic,  eqiial  in  both  valves ;    ligament  alivincular, 


460 


MOLLUSCA 


PHYLÜM  VI 


luaximiim    m 


resilium  suh-internal ;  gills  filibranchiate  ivith  cUrect  and  reßected  li7iibs ;  foot  small 
digitiform,  usually  hyssiferous,  the  byssus  passing  through  the  gctpe  of  the  valves. 
Carboniferoiis  to  Receiit. 

Lima  Bi'ug.      Shell  inflated,  with  radial  sculpturc  ;  beaks  pointed,  and  separated 
by    a    lozenge  -  shaped    area  ;    edentuloiis. 
Carboniferoiis    to    Recent 
Mesozoic  (over  300  species). 

Subgenera  :     Lima    s.    s.     {lladula 
aiict,  71071  Gray)  (Fig.  720).     Shell  wil 
strong  radial  ribs. 


Fio.  722. 

Lima  (Limatula) 
it  ihbosa  S o w. 
ijower  Oolite ; 
üayeux,  Calvados. 


Fio.  720. 

Lima  peetinoides  Sow. 
Lower  Lias ;  Balingen, 
Würteinberg.     i/j. 


Fig.  721. 

Lima  {Flagiostoma)  gigantea  Sow.     Lower  Lias  : 
Göppingen,  Würtemberg.    2/.^. 


Fig.  723. 
Limaea       dupli- 
cata  Goldf.     Great 
Oolite ;  Lan grüne, 

Xoi-iiiaiidy. 


Fig.  724. 
Ctenostreon  proboscidea  Sow.     Oxfordian  ;  Dives,  Calvados. 

Flagiostoma  Sow.  (Fig.  721).     Sniooth  or  finely  striated. 

Limatula  Wood  (Fig.  722).     Medially  ribbed,  laterally  smooth,  valves  not  gaping. 

Limaea  Bronn  (Fig.  723).  Small,  with  taxodont  armatiire  at  the  angles  of  the 
hinge.     Lias  and  Recent. 

Ctenostreon  Eichw.  (Fig.  724).  Compressed,  irregulär,  thick-shclled,  with  coarse 
radial  ribs.     Upper  Jura.     Badiotella  Bittner.     Alpine  Trias. 


CLARS  I 


PELECYPODA 
Superfamily  8.     ANOMIACEA   Herrmannsen. 


4G1 


Shell  monomyarian,  not  alate ;  edentulous  or  isodont,  usually  sessile ;  shell  substance 
nacreous,  tuhidiferous,  ivith  traces  of  a  prismatic  layer ;  area  ohscure,  usually  small, 
amphidetic  ;  ligament  ohscure,  ivith  an  alivincular  internal  resilium ;  (jills  filibranchiate, 
mantle  lohes  free ;  foot  small,  grooved,  digitiform  ;  dioecious ;  marine. 


Family  37.    Anomiidae  Gray. 

Shell  variable,  irregulär  and  inequivalve  when  sessile,  byssiferous  vjhen  young  ;  in 
most  genera  the  hyssus  becomes  modified  to  a  calcißed  or  horny  flug  ^Kissing  through 
a  foramen  in  the  right  valve,  and  fastened  to  other  ohjects,  a  condition  which  may  he 
permanent  or  transient ;  area  small,  amphidetic ;  ligament  amphidetic,  more  or  less 
internal,  supplemented  by  an  internal  resilium,  for  which  the  crura  serve  as  chondrophores, 
ali-  or  multivincular ;  hinge  usually  edentulous,  rarely  rugose,  with  amorphous  inter- 
loching  rugosities  ;  posterior  adductor  small,  sub-central,  in  the  sessile  forms  reinforced  by 
the  pedo-byssal  muscles,  which  are  modified  for  Service  as  adductors.  (?)  Devonian.  Jura 
to  Kecent. 

Anomia  Müll.  Shell  thin,  sessile  by  tlie  calcified  byssus  passing  through  a  siiiiis 
or  Perforation  in  the  right  valve,  conforming  to  the  subjacent  surfece ;  the  left  valve 
more  convex,  with  four  miiscular  scars  on 
a  central  area ;  a  chondrophore  in  the 
lower  valve.     Jura  to  Eecent. 

(?)  Limanomia  Bouch.  Devonian. 
Hypotrema  d'Orb.  Jura  and  Cretaceous. 
Placunanomia  Brod.     Miocene  to  Recent. 

Garolia  Cantraine.  (Fig.  725).  Shell 
orbicular,  compressed,  radially  striated ; 
right  valve  with  a  byssal  foramen  nearly 
closed  in  the  adult ;  resilium  much  as  in 
Anomia  ;  adductor  scar  single.  Eocene  ; 
Egypt. 

Subgenus :  Wakullina  Dali.  Smooth  ; 
byssal  foramen  obsolete  ;  the  resilium  received 
on  diverging  crura  on  the  upper  valve.  Oligo- 
cene  ;  Florida. 

Placenta  Retzius  {Placuna  Brug. ; 
Placunema  Stob;  Pseudoplacuna  Mayer). 
Shell  free,  orbicular,  thin,  very  compressed ; 
the  resilium  with  long,  unequal  crura. 
Tertiary  and  Recent. 

Ephippium    Bolten.       Like    Placenta, 
but  the  Shell  radially  waved  ;  young  with  a  small  byssal  Perforation,  which  becomes 
closed  and  obsolete  in  the  adult.     Tertiary  and  Recent. 

Placunopsis  Morr.  and  Lyc.     Shell  rounded,  imperforate,  free,  or  sessile.     Jura. 

Hemiplicatula  Desh.  {Semiplicatula  Fisch.) ;  Saintia  Raine.  Eocene.  Paranomia 
Conrad.      Ripley  Group.     Monia  Gray.     Miocene  to  Recent ;  California. 

Section  E.     Dysodonta  Neumayr  (emend.). 
Superfamily  9.     MYTILACEA   Färussac. 

Shell  anisomyarian,  usually  equivalve,  not  alate  or  notched  for  a  hyssus,  edentulous  or 
dysodont ;  shell  substance  sub-nacreous,  rarely  more  or  less  prismatic,  with  a  rom^icuons 


Fic.  725. 

Carolia  placunoides  Cantr.     Eocene  ;  Wadi  el  Tih,  near 

Cairo,  Egypt.     Interior  of  both  valves,  2/3. 


462 


MOLLUSCA 


PHYLUM  VI 


epidermis ;  area  amphidetic  or  ohscure ;  ligament  parivincular,  usually  opisthodetic  and 
external ;  gills  usually  ßlibranchiate ;  mantle  lobes  without  ocelli,  iiiore  or  less  free^ 
generally  with  the  anal  siphon  complete  and  the  hranchial  incomplete  ;  foot  small,  digiti- 
form,  gi'ooved,  hyssiferous  ;  monoecious  ;  mostly  marine. 

Family  38.     Modiolopsidae    Fisclier  (emend.). 

Shell  modioliform,  usually  eqidvalve,  ß'ee,  thioi,  with  suh-equal  adductor  scars ; 
ligament  deep-seated  ;  hinge  edentulous  or  dysodont  ;  sometimes  hyssiferous.  Ordovician 
to  Cretaceous. 


The  lieavier  fornis  show  an  obtuse  ridge  or  two  extending  from  the  beaks  toward  the  basal 
margin.     The  pedal  scars  are  separate  from  and  behind  the  anterior  adductors.     The  forms 

included  here  aj)pear  to  be 
the  prototypes  of  the  Myti- 
lidae,  from  which  they  difFer 
chiefly  in  those  characters 
that  are  common  to  most  of 
the  ancient  types,  such  as  the 
sub-equality  of  the  adductor 
scars  and  their  more  dorsal 
Situation.  The  recent  Idas  is 
very  similar. 

Modiolopsis  Hall  (Fig. 
726).  Valves  elongate- 
oval,  closed,  with  iiearly 
terminal  beaks,  narrow 
hinge  plate,  and  edentulous 
hinge,  Ordovician  and 
Silurian. 

Modiomorpha  Hall. 

Similar,  but  with  a  wider 
hinge  plate,  and  Single, 
oblique,  elongate,  posterior 
ridge  -  like  tooth.  De- 
vonian. 

Myoconcha    Sow.    (Fig. 

727).     Hinge  usually  with  an  elongate  cardinal,  and  a  long,  weak,   lateral  tooth  in 

the  right  valve  ;  otherwise  resembling  Modiolopsis.    Carboni- 

ferous  to  Cretaeeous. 

(?)  Hippopodium  Sow.     Thick,  infiated  ovate,  concentric- 

ally  waved.     Hinge  with  a   long,  blunt,  oblique,  cardinal 

tooth,  or  edentulous  ;  adductor  scars  strong.     Jura. 

Modiolodon,  Whiteavesia,  Eurymya,  Aristerella,  and  Prolo- 
hella   Ulrich;    Ordovician;    North    America.      Goniophora 

Phillips.     Silurian  and  ]3evonian.     Orthonota  Conrad.     De- 

vonian.     Orthodesma  Hall  and  Whitf.     Ordovician;   North 

America. 

Family  39.     Mytilidae    Fleming. 

Shell  equivalve,  very  inequilateral^  heteromyarian,  slightly 
gaping,  typically  dysodont ;  area  amphidetic  or  noite  ;  ligament 
usually  external^  deep-seated;  rarely  with  an  alivincular 
internal  resilium ;  pallial  line  simple;  mantle  lohes  united 
helow  the  anal  siphon,  otherwise  free;  generally  hyssiferous. 
Devonian  to  Kecent. 


Pio.  726, 


Modiolopsis  modiolaris 
(Conrad).  Ordovician ;  Cin- 
cinnati,  Ohio.    i/i. 


Fig.  727. 
Myoconclia  striatula  Goldf. 


Lower  Oolite ; 
Bayeux,  Calvados,     i/i- 


Fig.  728. 

Mytilus  suhlaevis  Sow.  Great 
Oolite ;  Minchinhampton,  Eng- 
land,    i/i- 


CLASS  T 


PELECYPODA 


463 


Mytilus  Liim.  (Fig.  728).  Shell  elongated,  thiii,  witli  terminal  pointed  beaks ; 
valves  wider  and  rounded  beliind,  gaping  a  little  for  tlie  byssus,  smooth  or  radially 
sculptured,  witli  sniootli  niargins,  conspiciious  epiderinis,  and  a  thin  nacreous  layer  ; 
hinge  with  a  few  small  teeth  iinder  tlie  beaks,  or  edentulous.      Trias  to  Recent. 

Pachymytilus  Zitt.  (Fig.  729).      Shell  thick,  trigonal ;   the    front  margin   deeply 

impressed.     Upper  Jura. 

Modiolus  Lam.  (Figs.  730,  731).    Like  Mytilus, 


Pacliy mytilus  petasus  d'Orb.     Coral-Rag  ; 
Coulaiige-.sur-Yonne.     2/3. 


Fi(!.  730. 

Modiolus    OS-  ^^'^-  "^l- 

per  US      Sow.  Modiolus     imhri- 

Great     Oolite ;  cahis  Sow.     Middle 

Langrune,  Cal-  Jura ;    Baiin,   near 

vados.     i/x-  CracoWjAn.stria.i/i- 


Fio.  732. 

Lithopliagus  inclusus (Ph\l\.). 
Qreat  Oolite  ;  Minchinhamp- 
ton,  England.  A,  B,  Shell, 
1/1.     ü,  Mould  of  the  burrow. 


but  the  beaks  not  terminal,  edentate,  anteriorly  rounded  and  wider.  Devonian  to  Recent. 

Subgenera  :  Modiolaria  Loven.  Small,  radially  sculptured  toward  the  ends,  usually 
smooth  toward  the  middle,  modioliform.  Tertiary  and  Recent.  Creiiella  Brown.  Small, 
rounded,  radially  sculptured  all  over.'    Tertiary  and  Recent. 

Stavelia  Gray.     Recent.     Valves  spirally  twisted. 

Litliophagus  Meg.  {Lithodomus  Cuv.)  (Fig.  732).  Sub-cylindrical,  with  rounded 
ends  ;  perforating  coral,  limestone  and  other  substances,  in  wliieli  the  animal  forms 
flask-shaped  excavations ;  moulds  of  the  latter  are  often  found  in  the  fossil  State. 
Carboniferous  to  Recent. 


Family  40.     Dreissensiidae    Gray. 

Shell  mytiliform,  equivalve,  of  prevailingly  prismatic  suhstance  ;  area  linear ,  amphi- 
detic ;  ligament  sub-internal ;  anterior  adductor  and  pedal  protractors  inserted  on  a 
myophoric  septum ;  mantle  lohes  united  to  form  anal  and  hranchial  siphons,  and  also 
ventrally  with  a  pedal  opening  ;  pallial  line  usually  simple  ;  gills  reticulate ;  otherwise 
as  in  Mytilus.     Tertiary  to  Recent.     The  relations  of  this  family  are  in  question. 

Dreissensia  Van  Ben.  {Tichogonia  Rossm.)  (Fig.  733).     Smooth,  without  a  pearly 
layer,  with  a  Single  apical  septum  ;  fluviatile  and  estuarine.     Eocene 
to  Recent ;  Europe. 

Mytilopsis  Conr.  Mytiliform,  small,  thin ;  myophore  for  the 
pedal  protractor  distinct  from  that  which  supports  the  anterior 
adductor.      Tertiary  and  Recent ;  America. 

Gongeria  Partsch  (Fig.  734).  Sub-quadrate,.  heavy,  large ; 
myophores  as  in  Mytilopsis.  Very  profuse  in  the  Neocene  of  Eastern 
Europe  (Congeria  beds). 

IJreissensiomya  Fuchs.  Notalgie  for  being  the  only  example  of  the 
Mytilacea  with  a  distinct  pallial  sinus.     Miocene  ;  Eastern  Europe. 

Septifer  Recluz.     Valves   wuth   strong    radial   or  divaricate   sculpture. 
Tertiary  and  Recent. 


Fig.  733. 

Dreissensia  brardi 
Faujas.  Miocene ; 
Weissenau,  near 
Mayence.     Vi- 


Marine 


464  MOLLUSCA  phylum  vi 

The  Eeceiit  families,  Juliidae  and  Modiolarcidae,  if  their  validity  be  confirmed, 


Pi(i.  734. 
Congeria  suhglohosa  (Partscli).     Upper  Mioceiie  ;  Inzersdorf,  near  Vienna. 

may  find  a  place  in  tliis  vicinity.     Julia  Gould  {Prasina  Desh.),  and  Berthelinia  are 
reported  from  the  Tertiary,  the  former  in  the  Oligocene  of  Florida. 

Order  2.     ANOMALODBSMACEA    DalL 

Superfamily  1.     ANATINACEA   Dali. 

Anomalodesmacea  with  \/-shaped  reticulate  gills  not  secreting  a  calcareous  tuhe  exterior 
to  the  shell. 

This  group  is  divisible  into  sections  as  follows : — (a)  Eusiphonia,  with  long  siphons,  and 
the  lithodesma,  when  present,  at  the  anterior  end  of  the  internal  resilium,  and  external  to 
the  mass  of  the  resilium  ;  and  (&)  Adelosiphonia,  with  short  siphons,  the  lithodesma  dividing 
the  mass  of  the  resilium  mesially. 


Section  A.     Eusiphonia. 

Family  1.     Pleuromyacidae    Zittel. 

Shell  slightly  inequivalve,  hinge  with  an  ohscure  protection  or  edentulouSj  the  cardinal 
horder  of  one  valve  covering  that  of  the  other  valve,  ivhich  is  supplemented  hy  a  sort  of 

laminar  nymph,  the  ligament  suh-internal  hetween 
them ;  area  inconstant  or  ohscure;  pallial  sinus 
present ;  ralves  closed  or  slightly  gaping.  Trias  to 
Lower  Cretaceous. 

Pleuromya  Ag.  {Myacites  auct.)  (Figs.  735,  736). 
Posterior  side  longer,  somewliat  gaping,  hinge 
margin  with  a  thin  horizontal  lamina  in  eacli 
valve,  the  left  inferior,  the  margin  wdtli  a  feeble 
notcli  behind  the  lamina ;  ligament  parivincular. 
Trias  to  Lower  Cretaceous ;  almndant,  but  seldom 
.well  jjreserved. 

Fkj.  735.  Gresslya  Ag.  (Fig.  737).      Like  Pleuromija,   but 

Pleuromya  peregrinaA'Ovh.  Upper  Jnra ;   the  right   hinge   margin   proi'ectinff   over   the   left, 

Chorostköw,   near  Moscow.     A,    Internal  ,      •  ^^         ^       ^         •  ^  ^•  .  •    •         -, 

mouid,  i/i-    li,  Hinge.  anterior   side   snort,  Wide  ;    ligament  parivincular, 

almost  internal,  attached  to  an  internal  nympli- 
like  callosity  in  the  right  valve,  which  appears  as  a  groove  on  internal  moulds. 
Abundant  in  the  Jura,  especially  in  the  Lias. 


CLASS  I 


Geromya   Ag.  (Fig.    738). 


A-.     .Middle  Juni,  Zii 
jaczki,  Poland.     i/i- 


PELECYPODA 

Cordalc,    iiillal 


Fki.  737. 

Crrss/i/,,,  htfirnsin, 
Ai^-.  Lowcr  Oülite 
Tainiie,  öartlie.     i/i- 


465 

],  witli  i'atlici'  aiilcrior,  |iI(i.-(il;\  rous 
--;  hiii^v  iiiai\^iii  u\  ilic  ri^lit  valve 
ri(»r,    (■(Iciiluious,    Ijiil    willi    a    blunt 


Fir;.  738. 

Ceromija  cf.  aalcnsls  Queiist.     Middle  Jura  ; 

Kneuttingeu,  Lonaine.     Hinge,  1/2' 


elongated  process  in  front  of  an  internal  callosity.    Chiefly  occnrring  as  moulds.    Jura. 


Family  2.      Pholadellidae    Miller  (eniend.). 

Shells  obovate,  usually  attenuated  hehind  and  slightly  gaping,  hinge  margin  thin, 
edentulous,  ligament  parivincular,  external ;  posterior  adductor  scar  large.     Paleozoic. 

Allorisma  King.  E longa te,  arcuate,  tlie  pallial  line  sinuated,  anterior  side 
sliorter,  sometimes  witli  a  liinule  ;  sciüpture  strengest  mesially.  Carboniferous  and 
Permian. 

Ehytimya     Ulricli,     Elongate,    sub-quadrate,    concentrically    waved,    tbe    waves 
stronger  anteriorly  ;  sculptnred  on  the  posterior  half  witli 
radiating  series  of  grannies  ;  lunnle  very  narrow.     Silurian. 
Pholadella   and    Gimitaria    Hall.      Devonian ;    North 
America. 

Family  3.      Pholadomyacidae  Gray. 
Shell   suhstance    nacreous   and   cellulo  -  crystalline ;    gills 


Pliolniloiin/ii.  vnnrh:.«!,,;  S( 
MiddltNJui-a;  l'iezclinow,  l-olai 
Vi. 


completely  united,  hehind,  forming  a  septurii  heloiv  the  anal  chamher ;  foot  small,  with  an 

opisthopodium ;  siphons  long,  united  to  their  tips,  not  wholly  retradile,  naked ;  ventral 

commissure  of  the  mantle  ivith  a  pedal  and  an  opisthopodial  foramen.     Shell  thin,  equi- 

VOL.  I  '  2  H 


466 


MOLLUSCA 


PHYLUM  VI 


valve,  (japing,  edentulous,  or  loith  an  ohscure  subumbonal  tuhercle ;  ligament^  and 
resilium  external,  opisthodetic,  seated  on  nymphae ;  area  obsolete  or  obscure,  not  amphi- 
detic  ;  beahs  entire  ;  pallial  sinus  well  marked  ;  marine.      Trias  to  Recent. 

Pholadomya  Sow.  (Figs.  739-741).  Shell  thin,  sub-ovate,  with.  radial  and  coii- 
centric  sculpture,  inflated,  and  with  rather  prominent  beaks  ;  hinge  edentulous,  or 
with   an   obscure   thickening ;  scars   feeble,  pallial   sinus   moderately   deep.      In   the 


Fia  742. 

Goniomya  duhoisi  Ag.  Inferior  Oolite ;  Bayeux, 
Calvados.  A,  Shell,  i/j.  B,  Surface  showing  puncta. 
tions,  magnified. 


Hmnomya  (Arcomya)  calceiformis  Ag.     Inferior  Oolite  ; 
Les  Moutieux,  near  Bayeux,  Calvados.    2/3. 


posterior  dorsal  region  the  radial  sculpture  is  usually  feeble  or  absent.  Lower  Lias  to 
Recent ;  formerly  very  abundant,  but  now  represented  by  a  single  species  from  the 
Antilles,  P.  Candida  Ag.,  and  another  from  Japan. 

Procardia  Meek.      Includes  those  forms  with  an  escutcheon.     Jura. 

Goniomya  Ag.  (Fig.  742).  With  V-shaped  sculpture.  Lias  to  Cretaceous ;  very 
plentiful  in  Middle  and  Upper  Jura. 

Homomya  Ag.  {Arcomya,  Myopsis  Ag.  p.p.)  (Fig.  743).  Distinguished  from  the 
typical  Pholadomyas  by  its  smooth  or  very  finely  sculptured  shell,  without  ribs. 
Trias  to  Cretaceous. 

(?)  Machomya,  Plectomya  Loriol ;  Mactromya  Ag.     Jura  and  Cretaceous. 


Family  4.     Anatinidae  Dal]. 

Soft  parts  like  Pholadomya,  the  foot  small  and  grooved,  ventral  foramina  small,  and 
the  siphons  with  a  horny  integument,  not  entirely  retractile.     Shell  sub-equivalve,  truncate, 

or  gaping  behind,  edentulous,  the  resilium  internal  between 
two  spoon-like  chondrophores  vertically  directed  and  often 
supported  by  buttresses ;  ligament  obsolete  or  absent ;  area 
obsolete;  beahs  transversely  fissured ;  pallial  sinus  well 
marked  ;  monoecious  ;  marine.     Jura  to  Recent. 

Anatina  Lam.  {Platymya,  Cercomya  Ag. ;  Plicomya 
Stol.)  (Fig.    744).     Shell  thin,  nearly  equivalve,  con- 
centrically  but  feebly  sculptured,  posterior  side  shorter 
than  the  anterior.     Jura  to  Recent.     Laternula  Bolten,  is  a  prior  name. 
Periplomya  and  Anatimya  Conrad  ;  Rhynchomya  Agassiz.      Cretaceous. 


Fio.  744. 

Anatina  producta  Zittel.     Upper 
Cretaceous ;  Gosau  Valley,  Austria 


Family  5.     Periplomatidae  Dali. 

Shell  sub-nacreous,  conspicuqusly  inequivalve,  nearly  closed,  edentulous ;  the  resilium 
internal,  between  two  anteriorly  or  vertically  directed  chondrophores,  often  buttressed,  the 
lithodesma  rarely  ivanting ;  ligament  and  area  absent ;  beaks  fissured ;  pallial  sinus 
broad  and  shallow  ;  siphons  separated  to  their  bases,  naked  and  wholly  retractile ;  mono- 
ecious; marine.     Tertiary  and  Recent. 


CLASS  I  PELECYPODA  467 

Periploma  Schiiin.  Shell  oval  ov  rounded,  siiiootli  or  witli  faiiit  coucentric  Striae  ; 
lithodesnia  preseiit.     Tertiaiy  and  Eecent. 

Gochlodesma  Couth.  Buttress  of  the  chondrophore  posteriorly  directed  ;  no  litlio- 
desiiia.      Pliocene  and  Recent. 

Bontaea  Leach  {Ligula  p.p.  Mont.) ;   Tyleria  Adams.     Kecent, 

Family  6.     Thraciidae  Dali. 

Shell  earthy  and  cellulo-crystalline,  not  nacreous  ;  inequivcdve,  thin,  edentulous,  often 
with  a  granulär  surface ;  licjament  and  resilium 
chiefly  external,  opisthodeticj  parivincular,  seated 
on  posteriorly  directed  nymphae ;  area  absent, 
heaJcs  usually  entire ;  valves  nearly  closed,  with 
pallial  sinus ;  mantle  openings  small ;  siphons 
long,  separated  to  their  tips,  nahed ;  monoecious ; 
marine.     Jura  to  Recent. 

Thracia  Leach  {Gorimya  Ag.)  (Fig.  745). 
Shell  smooth  or  concentrically  striated,  with 
granulär  surface,  usually  more  or  less  rostrate. 
Trias  to  Recent. 

Gyathodonta  Conr.      Shell  with  oblique   or  ■^^^'  '^'^^• 

angular  waves  of  sculpture,  otherwise  like  the    ^'"««^  ^«<^ß»-^  Ag.^^Upper  Jum 
preceding.     Tertiary  and  Recent. 

Bushia  Dali ;  Asthenothaerus  Carpenter.     Recent. 


Family  7.     Myochamidae  Dali. 

Shell  very  inequivalve,  free  or  sessile,  solid,  suh-nacreous,  edentulous,  the  dorsal 
margins  of  one  valve  overlapping  those  of  the  other,  which  fit  into  corresponding  depres- 
sions  in  the  shell  wall;  ligament  amphidetic,  external  or  ahsent ;  resilium  internal, 
alivincular ;  area  amphidetic  or  obsolete,  a  false  area  formed  on  each  side  of  the  beaks  by 
the  flattened  cardinal  margin  of  the  valves ;  shell  closed  ;  pallial  sinus  small.  Tertiary 
and  Recent. 

The  gills  and  siphons  of  Myochama  Stutchbury,  which  lives  sessile  on  shells,  are 
more  like  those  of  Thracia  than  of  the  Pandoridae,  with  which  it  lias  usually  been 
associated.  The  anatomy  of  Myodora  is  unknown.  Its  minute  area  curiously  recalls 
that  of  Spondylus,  and  it  is  free. 

Section  B.     Adelosiphonia. 
Family  8.     Pandoridae  Gray. 

Shell  compressed,  inequivalve,  free,  solid,  with  nacreous  and  prismatic  layers ;  the 
dorsal  edges  of  the  valves  overlapping^  but  not  socheted,  with  dentiform  crural  ridges  on 
either  side  of  the  resilium,  but  no  true  teeth ;  ligament  amphidetic,  external,  obsolete; 
resilium  internal,  opisthodetic,  usually  reinforced  on  its  anterior  surface  by  a  mesial 
elongate  lithodesma  ;  area  none ;  valves  closed,  beaks  entire,  pallial  line  simple ;  marine. 
Cretaceous  to  Recent. 

Pandora  Brug.  Diverging  crura  without  connecting  lamellae ;  buttress  and 
lithodesma  absent.     The  subgenus  Kennerleya  has  a  lithodesma.     Tertiary  and  Recent. 

Goelodon  Carp.  Crura  of  the  left  valve  united  by  a  transverse  lamella.  Glidio- 
phora  Carp.  has  the  hinge  plate  buttressed  and  a  lithodesma.     Tertiary  and  Recent. 


468  MOLLUSCA  phylum  vi 

Family  9.      Lyonsiidae  Dali. 

Shell  inequivalve,  thin,  sub-nacreous,  edentulous ;  ligament  obsolete,  the  resilium 
internal^  uniting  the  edges  of  a  long,  mesial  lithodesma  to  a  narrow  chondrophoric  sub- 
marginal ridge  on  each  valve ;  beaks  entire,  valves  nearly  closed,  pallial  sinus  distinct ; 
marine.     Tertiary  and  Kecent. 

Lyonsia  Turton.  Small,  thin,  posteriorly  elongate  with  delicate  radiating  sculp- 
ture.     Tertiary  and  Eecent. 

Entodesma  Pliilippi,      Kecent.     Actinomya  Mayer.      Eocene  ;  North  America, 

Family  10.     Lyonsiellidae    Dali. 

Shell  nearly  equivalve,  sub-nacfeous,  with  a  more  or  less  distinct  tubercle  in  front  of 
the  resilium  on  the  dorsal  margin ;  ligament  obsolete,  cartilage  internal  with  a,  large 
lithodesma ;  area  obscure  or  absent ;  beaks  entire ;  valves  almost  closed ;  pallial  sinus 
obsolete.     Tertiary  and  Recent. 

Halicardia  Dali  ;  Lyonsiella  Sars.     Chiefly  Recent. 

Superfamily  2.     ENSIPHONACEA  DaU. 

Differing  from  Anatinacea  by  the  formation  of  a  calcareous  tube,  which  may  include 
one  or  both  of  the  valves,  and  is  usually  furnished  with  a  perforated  anterior 
disk  surrounded  by  a  more  or  less  complete  f ringe  of  small  calcareous  tubules. 

Family  11.     Clavagellidae  d'Orbigny  (emend.). 

Shell  degenerate,  extremely  specialised  for  a  burrowing  life;  valves 
nacreous,  free  when  young  ;  when  adult,  one  or  both  merged  in  a  calcareous 
tube  anteriorly  discoid  and  fringed,  with  a  narroio  pedal  foramen  in  the 
middle  of  the  disk  ;  free  valves  edentulous,  the  ligament  external,  opisthodetic, 
supported  by  nymphs ;  pallial  line  sinuate  ;  tube  frequently  encrusted  with 
extraneous  material ;  marine.     Cretaceous  to  Recent. 

Glavagella  Lam.  (Bryopa  Gray ;  Stirpulina  Hol.)  (Fig.  746).  One 
of  the  valves  not  attached  to  the  tube  and  adductor  muscles  persistent. 
Cretaceous  to  Recent. 

Brechites  Guett.  {Äspergillum  Lam.).  Both  valves  merged  in  the 
tube,  anterior  adductor  reduced,  and  the  posterior  obsolete.  Pliocene 
„     ^,.        and  Recent. 

Fig.  746. 
Glavagella 

caüiati  Desh.  Superfaiüily  3.     POROMYACEA  DaU. 

Eocene;  Grig- 

Desiiayes)*    ^  Anomalodesmacea  having  modified  foliobranch  or  lamellar  gills,  slightly 

or  not  at  all  reticulated,  and  frequently  degenerate  or  even  absent;  valves 
free,  without  a  calcareous  tube  external  to  them ;  mantle  lobes  united,  with  siphons  and 
a  pedal,  but  no  opisthopodial  foramen  ;  the  cartilage  reinforced  below  by  a  lithodesma. 

Family  12.     Euciroidae  Dali. 

Shell  sub-equivalve,  nacreous  and  cellulo-crystalline,  externally  granulöse;  hinge 
with  a  strong  tubercle  in  the  right  valve  before  the  resilium,  and  the  dorsal  margins 
modified  to  overlie  and  underlie  each  other ;  ligament  obsolete;  resilium  opisthodetic, 
internal,  with  a  strong  lithodesma  ventrally ;  area  obscure  or  absent ;  a  depressed  false 


CLASS  I 


PELECYPODA 


469 


lumde  hefore  the  hcaks ;    valves  closed,  imllial  sinus   shalloiv,  nhscure ;    siphons  short, 
separate  ;  marine.      Tertiary  to  Receiit. 

Pecchiolia  Menegli.     Sliell  heavy  ;   beaks  spirogyrate,  distant  ;   sciilptiire  radial. 
Eocene  ;  Alabama.      Mioceiie  ;  Europe. 
Euciroa  Dali.      Recent,  abyssal. 

The  genera  Verticordia  Wood  ;  Trigonulina  d'Orb.  ;  Haiiris  Dali ;  and  (?)  Allo- 
pagus Stol.  {Hippagus  Desli.,  non  Lea)  are  included  linder  the  faniily  Verticordiidae. 
Tertiary  and  Recent. 


Family  13.     Poromyacidae  Dali. 

Shell  rounded,  nacreous  and  cellulo-crijstalline,  granulär  or  smooth  externally  ;  hinge 
with^  obscure  tuberdes  in  front  of  the  resilium ;  ligament  external,  opisthodetic  ;  resilium 
sub-internal  below  the  ligament,  with  a  small  lithodesma ;  area  obscure  or  absent ;  a 
depressed  false  lunule  in  front  of  the  beaks;  valves  nearly  or  entirely  closed;  pallial 
sinus  small  or  obsolete  ;  marine.     Cretaceous  to  Recent. 

Liopistha  Meek  {Gymella,  Psilomya  Meek)  (Fig.  747).  Eqiiivalve,  oval,  thin,  in- 
flated,  concentrically  or 
radially  striated,  gapiiig 
and  compressed  behind  ; 
beaks  prominent,  in- 
curved ;  hinge  with  a 
nymph  and  projecting 
process  on  eacli  side ; 
ligament  siinken,  partly 
external.      Cretaceous. 

(?)   Basterotia     Mayer 
{Eucharis      Recliiz,     non 
Peron).     Valves  sub-equal,  closed,  with  a  strong  tooth  in  the  right  and  two  in  the 
left ;  surface  granulär  ;  form  trapezoid.      Miocene  and  Recent. 

Poromija  Forbes  {Embla  Loven).  Ovate,  plump,  surface  granulär  ;  pallial  line 
irregularly  widened,  not  sinuate.     Eocene  and  Recent. 

Dermatomya  Dali.  Surface  smooth,  with  a  conspicuous  periostracum ;  pallial 
line  sinuate.     Recent,  abyssal. 

Cetomya,  Getoconcha  Dali  (ßilenia  Smith).     Recent,  abyssal. 


Fi(i,  747. 
Liopistha  frequens  Zitt.     Upper  Cretaceous  ;  Gosau,  Austria.     Vi^ 


Family  14.     Cuspidariidae  Dali. 

Shell  sub-equivalve,  rostrate,  earthy  or  cellulo-crystalline,  rarely  with  surface  granula- 
tions ;  hinge  edentulous  or  with  sub-umbonal  tubercula- 
tion,  sometimes  buttressed  ;  ligament  sub-internal,  anterior 
to  the  beaks  or  obsolete;  resilium  internal,  with  a  mesial 
or  ventral  lithodesma ;  area  amphidetic  or  obscure ;  valves 
closed  except  at  the  tip  of  the  rostrum  ;  pallial  line  simple  ; 
siphons  united  ;  marine.     Jura  to  Recent. 

Guspidaria  Nardo  {Neaera  Gray ;  Ryderia  Wilton) 
(Fig.  748).  Shell  concentrically  sculptured ;  hinge 
with  a  small  posteriorly  inclined  chondrophore  in  each 

valve,  and  an  elongated  ridge  behind  it ;    ligament  always  anterior  to  the   bciks 

when  present.     Jura  to  Recent. 

Subgenera  :   Cardiomya  Adams  ;  Avith  radial  sculpture  and  a  posterior  lateral  tooth  in 
the  right  valve.     Lciomya  Adams  ;   smooth,  with  an  anterior  cardinal  in  each  valve,  and 


Fi(i.  748. 

Cusindaria  cuspidata  Olivi. 
Miocene  ;  Baden,  near  Vienna. 


470  ■  MOLLUSCA  phylum  vi 

anterior  and  posterior  laterals  in  the  right  valve  only.  Plectodon  Carp.  ;  surface  granulated. 
Rhinoclama  D.  and  S. ;  like  Plectodon,  but  without  cardinal  teeth.  J'ropidomya  D.  and 
S.  ;  hinge  witli  a  buttress,  one  anterior  cardinal,  but  no  lateral  in  either  valve.  Halonymplia 
D.  and  S.  ;  right  valve  with  a  single  cardinal,  no  other  teeth  in  either  valve,  a  conspicuous 
posterior  laminar  buttress  in  each  valve.     Luzonia  Dali.     Tertiary  and  Recent. 

Myonera  Dali  and  Smith.     Shell  thin  with  concentric  waves  and  sparse  radial 
ribs  ;  hinge  edentulous  ;  rostrum  short,  rounded.     Recent,  abyssal. 

(?)  Gorhurella  Lycett.     Middle  Jura.     Spheniopsis  Sandberger.      Tertiary. 


Order  3.     TELBODBSMACEA  DaU. 

A.  Pantodonta. 
Laterals  exceeding  tivo  in  any  one  group. 

Family  1.     Allodesmidae  Dali  {Gycloconchidae  Ulrich). 

Shell  rounded;  valves  equal,  free,  closed,  with  feehle  concentric  sculpture ;  area 
linear,  amphidetic ;  ligament  suh-external,  parivincular,  opisthodetic ;  adductor  scars 
suh-equal,  pedal  scars  ahove  and  distinct  from  the  adductors  ;  pallial  line  entire  ;  hinge 
with  one  or  two  lateral  laminae  on  each  side  of  the  beaJc,  the  posterior  helow  the  ligament, 
received  into  corresponding  grooves  on  the  right  valve;  cardinal  teeth  radially  grooved ; 
one  or  two  in  each  valve,  those  in  the  right  valve  stronger.     Ordovician  and  Silurian. 

This  family,  as  suggested  by  Neumayr,  probably  exemplifies  the  first  step  in  the  develop- 
naent  of  the  Teleodesmacean  hinge.  But  it  must  be  adraitted  that  its  amphidetic  though 
linear  area,  the  occasional  multiplication  to  three  of  the  lateral  laminae,  and  the  sub-ligament- 
ary  localion  of  the  hinder  laminae,  are  very  reminiscent  of  the  prevalent  Silurian  Schizodont 
type,  and  the  family  can  be  adraitted  to  the  Teleodesmacea  only  as  a  probable  ancestor,  rather 
than  a  perfectly  developed  type  of  the  modern  assemblage. 

Orthodontiscus  Meek  {Cycloconcha  Miller ;  (?)  Anodontopsis  M'Coy).  Ordovician 
and  Silurian. 

Ällodesma  Ulrich.  Like  Orthodontiscus,  but  more  elongate,  the  beaks  more 
anterior,  the  anterior  adductor  scar  buttressed  by  a  radial  ridge,  and  the  anterior 
lateral  teeth  short  or  absent.     Ordovician 

B.    DiOGENODONTA. 

Laterals  normally  one  or  two,  and  cardinals  three  or  less,  in  any  one  group. 

Superfamily  1.     CYPEICARDIACEA  Dali. 

Lobes  of  the  mantle  partly  closed  ventrally ;  anterior  lateral  laminae  absent,  or 
grouped  with  the  cardinal  teeth,  short  and  obscure. 

Family  2.     Pleurophoridae  DalLi 

Shell  substance  cellulo-cry stalline  ;  valves  equal,free,  closed  ;  adductor  scars  sub-equal, 
free  from  the  pedal  scars ;  pallial  line  entire,  or  feebly  sinuated ;  area  obscure ;  liga- 
ment external  or  seated  in  a  groove,  parivincular ;  margins  of  the  valves  usually  piain ; 
hinge  with  one  left  and  two  right  posterior  laminae,  the  anterior  laminae  absent  or  con- 
fused  with  the  cardinals ;  two  or  three  cardinal  teeth  in  each  valve,  of  which  the  posterior 
in  both  valves  is  sub-parallel  to  the  dorsal  shell  margin,  and  in  the  right  valve  is  usually 
bifid.  Mantle  with  a  moderate  pedal  and  two  siphonal  openings,  the  latter  usually  not 
produced  into  tubes.     Devonian  to  Recent. 

1  Cyprinidae  p.p.  of  authors,  but  this  name  cannot  be  used. 


CLARS  I 


PELECYP0DA 


471 


This  family,  so  well  known  under  the  preoccupied  nanie  Cyprinidae,  probably  shared  the 
same  origin  as  the  Astartidae,  and  tlie  two  do  not  definitely  separate  until  the  Jura.  The 
Position  of  the  Paleozoic  ancestors  is  neeessarily  doubtful,  and  they  are  placed  ditferently 
by  different  authors.  The  group  i.s  divided  into  two  subfaniilies,  Pleurophorinae  and 
Vetiiellinae. 

.Pleurophorus  King  (Fig.  749).  Elongated,  siib-rectangular  ;  beaks  sub-terminal  ; 
surface  smootli  or  witli  radial  sculpture  ;  hinge  with  two  cardinal  teeth  in  each  valve  ; 


Pleurophorns  costatu!^  King.  Per- 
mian ;  Byers  Quarry,  England.  A, 
Shell,  Vi  Gifter  King),  ß,  Internal 
mould  Ironi  Gera,  Tlniringia  (after 
Geinitz). 


Anisrimrdia  elegans  Mun.-Chalra.     Kimmeridgian 
Cap  de  la  Heve,  near  Havre     i/i> 


anterior  adductor  scars    deep,  with   a  buttress-like  ridge  behind   it.     Devonian    to 
Trias  ;  especially  abimdant  in  the  Permian, 

Cypricardella    Hall   {Microdon    Hall);    Mecynodon   Keferst.;    Gypricardinia   Hall. 
Devonian.     Astartella  Hall.     Carboniferous. 


Änisocardia  Mun.-Chalni.  (Fig.   750). 


Rounded  or  trapezoid,  plump,  smooth  or 
radially  striate  ;  posterior  slope  some- 
tinies  keeled ;  hinge  with  a  strong 
sometinies  bifid  right  cardinal  behind, 
and  an  anteriorly  directed  front  cardinal; 


Venilicardia  cordiformis,  d'Orb. 
Gault ;  Seignelay,  Yonne. 


Fi(i.  753. 
Veniella  tumida  Nyst.   Crag ;  Antwerp. 


left  valve  with  a  forwardly  directed  anterior  and  a  posterior  cardinal  tooth.     Jura  to 
Tertiary. 

Boudairia  Munier-Chalm.     Like  Trapeziim,  but  with  a  sharp  keel  and  smooth 
area  behind,  anteriorly  with  concentric  ridges  ;  right  posterior  cardinal  bifid.     Upper 

Cretaceous. 


472  MOLLUSCA  phylüm  vi 

Trapezium  Huiniili.  emend.  Megerle  {Lihitina  Schiiin  .  ;  Gypricardia  Laiii.),  Shell 
elongate,  traj^ezoidal,  coiicentrically,  or  luore  rarely  radially  sculptured,  often  with  a 
posterior  keel ;  three  cardiiial  teetli  in  each  valve,  tlie  posterior  in  tlie  right  valve 
often  bifid.     Jura  to  Eecent. 

Plesiocyprina  Munier-Chalm.  Jura.  Gicatrea  Stol.  Cretaceous.  Goralliophaga 
Blainv.     Tertiary  and  Recent. 

Ärctica  Schum.  (Gyclas  Brug.  ;  Gyprina  Lam.)  (Fig.  751).  Oval  or  rounded,  in- 
flated,  concentrically  striated  ;  beaks  prominent,  curved,  cardinals  three  in  each  valve, 
the  left  posterior  often  bifid,  the  middle  left  cardinal  largest,  and  tlie  posterior  ridge-like. 
Abundant  in  the  Jura  and  Cretaceous,  and  represented  by  one  or  two  living  species. 

Venilicardia  Stol.  (Fig.  752).     Cretaceous.      Pygocardia  Mun.-Chalm.      Tertiary. 

Veniella  Stol.  {Venilia  Morton;  (?)  Goniosowa  Conr.)  (Fig.  753).  Left  valve  with 
the  anterior  cardinal  strong,  sub-triangular.      Cretaceous  and  Tertiary. 


Superfamily  2.     ASTARTACEA  Dali. 

Lohes  of  the  mantle  free  ventrally ;  lateral  laminae  ohscure,  wlicn  present  distant 
from  the  cardinals. 

Family  3.     Curtonotidae  Dali. 

Shell  short  and  heavy,  with  suh-terminal  heaJcs ;  valves  free,  eqnal,  closed ;  area 
ohscure ;  ligament  as  in  the  Astartidae ;  adductor  scars,  especially  the  anterior,  deep ; 
pallial  line  simple ;    hinge  plate  hroad,  vnthout  lateral  laminae ;    the  formula  of  the 

cardinals  ^ttt-i^j  or  uTttt-     Devonian  and  Carboniferous. 

This  group  is  inserted  conformably  with  the  opinion  of  Neumayr,  wlio  regards  it  as  the 
radical  of  the  Astartidae. 

Gurtonotns  Salter.  Oval,  cardinal  border  thick,  with  one  very  strong  tooth  in  the 
left,  and  a  strong  anterior  and  thin  posterior  tooth  in  the  right  valve.  Scars  of  the 
adductors  strong,  especially  the  anterior.      Devonian  ;  England. 

Prosocoelus  Keferst.     Devonian.     Protoschizodus  de  Kon.     Carboniferous. 


Family  4.     Astartidae  d'Orbigny  (emend.). 

Shell  suhstance  cellulo-crystalline,  with  a  pronounced  epidermis ;  shell  rounded  or 

suh-triangular,  usually  with  concentric  or  not  radial  sculpture  ;  valves  equal  or  suh-eqnal, 

free,  closed ;  area  distinct ;  ligament  and.  resilium  external,  parivincular,  opisthodetic ; 

heaks  prosocoelous  ;  adductor  scars  sub-equal,  with  a  distinct  anterior  pedal  scar  ;  pallial 

line  simple;    hinge  plate   distinct,   hinge  with  anterior   and  posterior 

lateral  teeth  and  their  respective  sockets,  usually  more  or  less  obsolete; 

cardinal   teeth  not  bifid  at  the  summit,  the  terminal  teeth  frequently 

obsolete.     Lobes  of  the  mantle  free  ventrally,  not  produced  into  siphons. 

Pio.  754.  Trias  to  Recent., 

Middle  Jura;  Gun'-  Astarte  Sow.  (Grassina  Lam.)  (Fig.  754).      Roundly  triangulär  or 

dershofen,  Aisace.    oval,  rather  compressed,  thick  ;  smooth  or  concentrically  sculptured  ; 
l^mule  impressed  ;  right  anterior  cardinal  strong. 

A  nmnber  of  genera  have  been  associated  with  Astarte  which  probably  belong  elsewhere. 
The  following  subgenera,  however,  are  Avorthy  of  recognition  ;  Coelastarte  Böhm,  Freconia 
Stol.  ;  Crassinella  Bayle,  non  Gnppy  (Fig.  755);  rroroMa  Biilini.  Jura.  Eriphyla  Gabb. 
Cretaceous.  Grotriania  Speyer  ;  Goodallia  Turton  (Yhj,.  1()1)  ;  Uhcdocyvm  Dali  ;  Diqitaria 
Wood  (Fig.  756).     Tertiary  and  Recent. 


SS  I  PELECYPODA  473 

02ns  Defr.  (Fig.  758).      Trigoiial,  cordate,  sinootli  or  coiMcutricnlly  sliialc;   beaks 


Fig.  757. 

Astarte  (Goodallia) 
milinris  Defr.  Eocene  ; 
Grignon,  near  Paris 
(after  Desliayes). 


Fig.  755. 

Astartc  ohllqua  Desh.     Inferior 
Ooiite ;  Bayeux,  Calvados. 


Fig.  756. 

Digitari  profunda  Desh. 
(as  Woodia).  Eocene ;  Aizy, 
near  Laon.  A,  Hinge,  en- 
larged.     B,  Shell. 


2)ronii]ieiit,  prosocoelous ;  limule  very  deep,  bordered   by  a  keel ; 
cardinal  teetli  long,  iiarrow  (2  :  1).     Trias  to  Cretaceous. 


Fig.  758. 


Opis    goldfussiana 

Opisoma  Stol.     Jura.     Seehachia  Neiiniayr.     Cretaceous.  theim*.    Würtemberg.^ 


Family  5.     Crassatellitidae  Dali. 

Shell  as  in   thr,  Ädartidae,  hut  the   valves  always  somewhat  unequal,  and  nsualhj 
Diore  or  less  radrufi',   fhe  heaks  compressed,  erect  or  opisthocoelous ;   liyanient  infernal, 


CrassatelUtcs  plumlmi  (Chem.). 


Fig.  750. 
Eocene  (Calcaire  Grossier) ;  Damery,  near  Epernay.    2/3. 


more  or  less  obsolete,  resilium  large,  wholly  internal,  attached  at  each  end  to  a  chondro- 
phoric  pit  in  the  hinge  plate  behind  the  cardinal  teeth ;  lateral  teeth  and  sockets  usually 
alternated  in  the  valves,  the  hinge  plate  heavy,  flat ;  the  posterior  cardinal  in  the  right 
valve  very  small  or  obsolete,  lüith  no  distinct  socket  in  the  opposite  valve  ;  füll  cardinal 


formula 


L  1010 
RIOIUI' 


Lower  Cretaceous  to  Kecent. 


Tlie  earlicr  foriiis  of  tliis  fiiniily  liave  a  sniall  resilium  close  to  the  nearly  ni.iVL^iiial  ülj.-i- 
ment.  Witli  iimc.  Liter  oin's  show  ;i  gradual  descent  of  tliese  organs,  until  in  sninc  of  \\\v 
niorc  spoeialiscd  iiioilcni  n|ii('sriitati\-es  tliere  is  no  approciable  liganient  rciiiainiiiLr.  and   tlie 


474 


MOLLUSCA 


PHYLUM  TI 


resilium  has  become  large  and  deeply  immersed.  The  parallelism  between  this  group  and 
the  Mactridae,  in  the  gradual  inimersion  of  the  ligament,  could  hardly  be 
niore  complete. 

Grassatellites  Kruger  {Grassatella  Lam.  1819,  non  Lam.  1799) 
(Figs.  759,  760).  Cretaceous  to  Kecent ;  represeiited  by  about  seventy 
fossil  and  forty  living  species. 

Triodonta  Koenen.  Oligocene.  Scamhula  Conrad ;  Bemondia 
Gabb  {Stearnsia  White) ;  Änthonyia  Gabb ;  Grassatellina  Meek. 
Cretaceous. 

(?)  Ptychomya  Ag.  Like  Grassatellites,  but  witli  radial  sculpture 
and  three  cardinals  in  each  valve.     Cretaceous. 

Grassinella    Guppy,    non    Bayle    {Gouldia    auct.,    non    Adams ; 


Fk 

Grassatellites 
hronni        Merian. 


Oligocene;    Wein-   Pseuderiphyla  Fisch.).     Small,   sub -triangulär,  very  compressed,  con- 
Vi.  centrically  ribbed.     Tertiary  and  Kecent. 


Superfamily  3.     CYRENACEA  Tryon. 

Gypricardians  which  have  become  specialised  for  fresh  or  brackish  water  conditions, 
and,  as  usual  in  such  cases,  have  developed  great  variability  of  character ;  usually  vivi- 
parous. 


Family  6.     Oyrenidae  Gray. 

Shell  porcellanous,  with  a  conspicuous  epidermis,  usually  with  concentric  sculpture ; 
valves  equal,  free,  closed,  usually  with  piain  margins ;  area  obscure  or  none ;  ligament 
and  resilium  external,  parivincular,  opisthodetic ;  adductor  scars  sub -equal,  separate 
from  the  pedal ;  pallial  line  simple  or  ivith  a  small  sinus ;  hinge  with  anterior  and 
posterior  laterals  usually  double  in  the  right,  single  in  the  left  valve,  distinctly  separated 
from  the  cardinals ;  cardinal  teeth  bifid.  at  the  summit,  three  in  each  valve  when  none 
are  obsolete.  Mantle  open  ventrally,  the  siphons  distinctly  developed,  short,  more  or  less 
united.     Lias  to  Recent. 

Many  of  these  forms  merge  with  one  another  as'we  recede  in  time.  The  Recent  American 
forms  and  many  fossils  show  a  pallial  sinus  ;  oriental  species  are  generali y  without  it.  In 
some  fossils  the  laterals  oF  the  right  valve  are  not  double, 

Gyrena  Lam.     Rounded,  sub-equilateral,  plump,  concentrically  sculptured,  with 
smooth  margins  ;  cardinals  three,  the  laterals  smooth.      Lias  to  Recent  (300  species) ; 
maximum     in    the    Cre- 
taceous and  onwards. 

Subgenera :  Corbicula 
Megerle  (Figs.  761,  762). 
Smaller  than  Gyrena,  and 
the  laterals  sharply  cross- 
striated.  Egeta  Adams. 
Compressed,  elongated, 

thin ;        almost       rostrate. 
Recent :  marine. 


Fig.  761 


CorMcula  fluminalis 
(Müll.).      Pleistocene ; 
Like    Teutschenthal,       near 
.  Halle,  Saxony. 

right 


Fir..  762. 

Corbicula  semistriata  Desli.     Oligocene 
(Gyrena  marls) ;  Flonheim,  near  Alzey.     i/^. 


Batissa    Gray. 
Gyrena,    but     the 

anterior  and  left  posterior  cardinals  feeble  or  obsolete ;  anterior  laterals  very  short, 
posterior  ones  elongated.  Upper  Cretaceous  of  Oregon,  and  living  in  Indo-Pacific 
region.  < 

^  Veloritina,  Leptesthes  Meek.  Laramie  Group.  Villorita  Gray  {Velorita  Gray,  1 847). 
Oligocene  to  Recent.  The  relations  of  the  Recent  Egeria  Roissy,  and  Profischeria  Dali 
{Galatea  Brug.,  non  Fabr.  ;  Fischeria  Bernardi,  non  Desv.)  are  not  positively  fixed. 


CLASS  I 


PELECYPODA 


475 


Family  7.     Sphaeriidae  Dali, 

Shell  as  in  the  Gyrenidae,  but  small,  with  a  feehle,  short  ligament,  a  simple  pallial 
line,  and  no  hinge  plate ;  cardinal  teeth  usiially  two  in  each  valve,  variable,  very  thin, 
often  nearly  parallel  to  the  hinge  margin  or  defective  in  pari  of  the  series  ;  laterals  as  in 
the  Gyrenidae,  distinct.     Upper  Cretaceous  to  Recent, 

Sphaerium  Scop,  {Gyclas  Lam.,  non  Bnig,).  Brancliial  siphon  complete  ;  shell 
equilateral,  inflated,  rounded.     Upper  Cretaceous  to  Recent. 

Subgenus  Eupera  Bgt.    Shell  compressed,  trapezoid.    Tertiary  and  Recent ;  sub-tropical. 

Gorneocydas  Ferussac  {Pisidium  Pfeitf.).  i  Shell  ineqiiilateral ;  branchial  siphon 
merged  with  the  pedal  opening.     Eocene  to  Recent. 


Superfamily  4.     CARDITACEA  Menke. 

This  group  appears  to  have  branched  off  from  the  Ästartoid  radical  in  the  early 
Mesozoic,  forming  in  one  sense  a  sort  of  parallel  series  with  the  Ästartidae,  with  ivhich  it 
is  contrasted  most  obviously  by  its  prevailing  radial  sculpture  and  prolonged  posterior 
cardinal  tooth. 

Family  8.     Oarditidae  Gill. 

Shell  as  in  the  Ästartidae,  but  usually  with  radial  sculpture,  the  pedal  adjacent  to 
the  anterior  adductor  scar  ;  ligament  external,  parivincular  ;  re'silium  usually  included 
in  the  ligament,  rarely  internal;  hinge  fully  developed,  with  the  laminae  as  in  the 
Ästartidae,  and  usually  obsolete;  the  anterior  cardinal  often  obsolete,  the  posterior  pro- 
longed parallel  with  the  dorsal  margin  even  below  the  ligament.     Füll  cardinal  formula 

p  •     Marine;  dioecious,  frequently  viviparous.     Trias  to  Recent. 

The  earlier  forms  approaeh  the  Ästartidae  and  Pleurophoridae  so  closely  that  they  can 
hardly  be  discriminated. 

Gardita  Brng.     Elongate,  quadrate,  with  prominent,  very  anterior  beaks  ;  sculp- 


m 


Fio.  7G3. 

Palacocardita  crenata 
(Münst.),  Upper 
Trias ;  St.  Cassian, 
Tyrol. 


Fi(i.  764. 
Venericanlia  imbricata  Lam.     Eocene  ;  Grignon,  near  Paris. 


tiire  radial  and  usually  imbricated,  commonly  with  a  lunule  ;  inner  margins  dentate  ; 
cardinals  long  and  oblique.     Trias  to  Recent. 

Palacocardita  Conr.  (Fig.  763).  Like  Gardita,  but  with  a  posterior  lateral 
tooth.     Trias  and  Cretaceous. 

Venericardia  Lam.  (Fig.  764).  Rounded  or  cordate ;  lateral  teeth  absent  or 
obsolete.     Cretaceous  to  Recent. 


476 


MOLLUSCA 


PHYLUM  VI 


Garditamera  Conr.  Elongated,  sub-mytiliform.  Pleuromeris  Conrad.  Small, 
eqiiilateral,  trigonal.  Cahjidogena  Dali.  Ovoid,  smootli  extenially.  Garditella 
Sinitli.  Siuall,  witli  internal  ligament.  All  Tertiary  and  Kecent.  Thecalia  Adams  ; 
Milneria  Dali.     Females  with  a  slielly  marsupium.     Eecent. 

Superfamily  5.     CHAMACEA  Geinitz. 

Garditian  forms  specialised  for  a  sessile  habit,  usually  with  exceptionally  spiral 
growth,  and  very  unegual  valves.     Marine. 


Family  9.     Diceratidae  Dall.^ 

Resemhling  Ghama,  but  with  the  adductors  usually  borne  on  myophoric  laminae,  or 
projections  which  o.re  prolonged  into  the  umbonal  cavity  below  the  hinge  plate ;  valves 
grotesquely  distorted,  sub-equal,  with  prolonged  and  twisted  umbones,  or  the  free  valve  is 
reduced  to  an  opercular  form,  spiral,  and  even  concave  ;  the  teeth  often  reversed  relatively 
to  their  Situation  in  Ghama.     Jura  and  Cretaceous. 

This  family  lias  possibly  been  derived  from  the  Megalodontidae  of  the  Paleozoic  and  early 
Mesozoic,  and  in  .tuvii  has  given  rise  to  a  branch  that  has  siu'vived  to  the  present  day 


Fig.  765. 

Diceras  arietinum  Lam.     Coral-Rag ; 
St.  Mihiel,  Meuse.    2u 


Fio.  766. 

A,  Diceras  arietmum  Lam.  Coral-Rag;  St.  Mihiel,  Meuse. 
Fixed  left  valve,  2/3.  B,  D.  zitteli,  Mun.  -  Chalm.  Tithonian ; 
Stramberg.  Right  valve,  2/3.  a,  a',  Anterior  and  posterior 
adductor  sears ;  c,  Major  cardinal ;  d,  Socket  for  left  anterior 
Cardinal ;  l,  Ligamentary  groove ;  s,  Buttress  ridge  before 
posterior  adductor  scar. 


(Chamidae),  as  well  as  to  others  that  became  extinct  at  the  close  of  the  Mesozoic.     In  all  cases 
the  forms  in  which  the  umbo  of  the  free  valve  is  coiled  have  preceded  more  specialised  forms 

^  For  the  Ghamacea  and  Rudistae,  Neumayr  proposed  the  term  Pachydonta.  For  special  litera- 
ture  see:  Zittel,  K.  A.  von,J)\Q  Bivalven  der  Gosaugebilde.  Denkschr.  Akad.  Wiss.  Wien, 
1864,  vol.  xxiv.—Gemmellaro,  O.  G.,  Caprinellidi  della  Ciaca  dei  dintorni  di  Palermo,  1865.— 
Munier- Ohalmas,  K,  Prodrome  d'une  Classification  des  Rudistes.  Journ.  deConchyl.,  1873,  vol.  xxi. 
—  White,  O.  A.,  Bull.  U.S.  Geol.  Surv.,  No.  4,  1884  ;  No.  22, 1885. —Bouville,  IL.  Several  papers  in 
Bull.  Soc.  Geol.  France  [3],  xiv.  p..  389  ;  xv.  p.  756  ;  xvi.  p.  699  ;  xvii.  p.  627  ;  xviii.  p.  324  ; 
1886-90. — di  Stefano,  G.,  Studii  stratigrafici  e  paleontologici  sul  systema  cretaceo  di  Sicilia. 
T.  Gli  Strati  con  Caprotina.  Palermo,  1888.  II.  Calcari  con  Polyconites  di  Termini-Imerese. 
Palaeont.  Ital.,  1898,  vol.  iv.  — Futterer,  K.,  Die  Oberen  Kreidebildungen  der  Umgebung  des  Lago 
di  Santa  Croce.  Palaeont.  Abb.,  1892,  n.s.  vol.  ii.—Böhvi,  G.,  Beiträge  zur  Kenntnis  der  Kreide  in 
den  Sitdalpen.  Palaeontogr.,  1894,  vol.  x\i.—Douville,  H.,  Etudes  sur  les  Rudistes.  Mem.  Soc. 
Geol.  France.  Paleontologie,  i.  iii.,  1890-96.— /^arowa,  G.  F.,  Sopra  alcune  Rudiste  Senoniane 
deir  Appenino  meridionale.  Mem.  Accad.  Torino,  1900,  ser.  2,  vol.  I.—Paquier,  F.,  Les  Rudistes 
urgoniens.  Mem.  Soc.  Geol.  France,  Paleont.,  1903,  vol.  xi.—Toucas,  B.,  fetudes  sur  la  Classifica- 
tion et  l'evohition  des  Hippurites.     tom.  cit.,  1903,  and  vol.  xxi.  p.  506,  1891. 


CLASS  I  PELECYPODA  477 

with  an  oiierculiforni  free  valve.     The  higlily  modified  Hippuritidae  evidently  indicate  the 
last  stage  of  the  evolutioiiary  series. 

Diceras  Lam.  {Heterodiceras,  Plesiodiceras  Mun.-Chalm. ;  Pseudodiceras  Gemm.) 
(Figs.  765,  766).  Shell  smooth,  inequivalve,  with  botli  valves  convex,  the  attached 
valve  larger,  dentition  normal  or  inverse  ;  beaks  prominent,  j^rosocoelous ;  ligament  as 
in  Chama,  supported  on  nympliae ;  right  valve  with  a  small  anterior  and  large 
elongated  curved  posterior  tootli  almost  parallel  with  the  hinge  margin ;  left  valve 


A,  Rcquicnia  ammonia  (Goldf.).     Urgonian  ;  Orgon,  Bouches-du-Rli6ne.     1/3.     B,  C,  Small  individual  of 
R.  {Toueasia)  lonsdalei  (Sow.),  from  same  locality.    B,  Left ;  C,  Right  valve,  Vi- 

with  a  Single,  large,  ear-shaped  tooth  in  front  of  the  elongated  socket  for  the  principal 
tooth  of  the  right  valve  ;  posterior  adductor  scar  on  a  projecting  buttress.    Upper  Jura. 

Apricardia  Gueranger.     Cenomanian  and  Turonian.     A.  carinata  Guer. 

Requienia  Matheron  (Fig.  767,  A).  Smooth,  very  inequivalve,  attached  by  the 
spirally  twisted  beak  of  the  left  valve  ;  right  valve  opercular,  spiral,  flat ;  teeth 
feeble  ;  posterior  adductor  scar  buttressed.  Lower  Cretaceous,  especially  the  Urgonian 
of  Southern  Europe,  the  Alps  and  Texas. 

Subgenus  Toueasia  Mun.-Chalm.  (Fig.  767,  B,  C).  Differs  from  Rcquicnia  in  having 
both  valves  keeled.     Urgonian  and  Cenomanian. 

Matheronia  Mun.-Chalm.     Urgonian  and  Cenomanian.     M.  vircjinae  (Gras.). 

Family  10.     Ohamidae  Lamarck. 

Bhell  suhstance  threefold,  the  inner  layers  porcellanoiis  and  tubulär,  the  middle 
obscurely  prismatic,  the  external  cellulo-crystalline  with  reticulated  tuhules  and  an  incon- 
spicuous  epidermis ;  valves  unequal,  irregulär,  one  of  them  sessile ;  closed,  usually 
rounded  in  form  with  conspicuous  sculpture,  often  differing  in  the  opposite  valves ; 
adductor  scars  suh-equal,  elongate,  pedal  scars  minute,  distant ;  ligament  and  resilium 
external  in  a  deep  groove,  parivincular,  opisthodetic ;  area  distinct,  prosodetic ;  beaks 
more  or  less  spiral,  prosogyrous ;  pallial  line  simple ;  hinge  plate  heavy,  arcuate ;  hinge 
frequently  with  a  minute  or  obsolete  posterior  lamina,  chießy  in  the  fixed  valve; 
cardinals  one  or  two  in  the  free  valve,  two  with  an  intermediate  socket  in  the  ßxed  valve  ; 
the  anterior  cardinal  broad,  usually  deeply  grooved  or  multißd,  the  posterior  simple,  long 
and  curved  parallel  with  the  dorsal  border ;  siphonal  orifices  not  produced  into  tubes ; 
adductors  each  composed  of  tivo  Clements.     Cretaceous  to  Receiit. 

Either  of  the  valves  of  Chama  may  be  the  attached  one,  but  the  teeth  in  the  fixed  valve, 
whether  right  or  left,  are  ahvays  the  same,  and  similarly  with  the  free  valve.  The  fixation 
is  generally  by  the  left  valve. 

Chama  lAnw.  (Fig.  768).  Nepionic  shell  rounded.  Ligament  sometimes  continued 
to  the  point  of  the  beaks,  as  in  otlier  bivalves  with  g}^rate  umbones ;  form  rounded, 


478 


MOLLUSCA 


PHYLUM   VI 


attached  valve  deeper  and  larger,  tlie  free  valve  flatter  ;  margiiis  usually  cross-striated, 
surface  lamellar  or  spinöse  ;  adductor  scars  large,  not  elevated.  Cretaceous  to  Recent; 
maximum  in  Eocene. 


Fig.  768. 
Chama  squamosä  Lam.     Eocene  ;  Hampshire,     i/j. 

Echinochama  Fiscli.  Nepionic  shell  elongated,  liaving  the  form,  liinge  and  otlier 
cliaracters  of  Gardita ;  attaclied  when  adolescent,  free  in  the  yoiing  and  adult  stages. 
Valves  sub-equal  and  similar;  surface  vermiculate,  spinöse,  witli  radial  ribs.  Oligocene 
and  Recent. 

Family  II.     Monopleuridae  Fischer. 


Shell  suhstance  loiihout  canals ;  shell  sessile,  closed,  very  inequivalve ;  free  valve  ivith 
the  cardinal  formula  101,  operculiform  or  slightly  spiral ;  fixed  valve  with  the  formula 
010,  conical,  unrolled  or  spiral;  area  wanting ;  ligament  external,  parivincular, 
opisthodetic.     Cretaceous. 

Monopleura  Math.  (?  Dipilidia  Math.)  (Figs,  769,  770).  Very  inequivalve,  smooth 
or  ribbed  ;  dentition  always  inverse  ;  attached  by  the  right  valve,  v^^hich  may  be  either 


Fig.  769. 


Fig.  770. 


Monopleura    trüobita    d"Orb.      Neocomian    (Schrattenkalk);    Orgon,  Monopleura    varians    Math.     Ur- 

Bouches-du-ßhone.    i/i.    A,  B,  Anterior  and  posterior  views.    C,  Interior       gonian  ;    Orgon,   Bouches-du-Rhone. 
attached  valve.  Interior  of  both  valves.     i/^. 

twisted  or  coniform  ;    left  valve  conical  or  flat ;    ligament  as   in  Chama ;    posterior 
adductor  scar  buttressed.      Lower  Cretaceous  ;  Southern  Europe  and  Texas. 

Valletia    Mun.-Chalm.       Neocomian.       Gyropleura    Douville.       Cenomanian    to 
Senonian.     Bayleia  Miin.-Chalm.     Turonian.     B.  pouechi  Mun.-Chalm. 


Family  12.     Caprinidae  d'Orbigny. 

Shell  suhstance  internally  furnished  with  large  parallel  canals,  the  external  layer 
valves  heavy,  irregulär,  unequal,  closed  ;  free  valve  spiral,  cardinal  formula 


PELECYPODA 


479 


101,  with  a  iiosterior  myophoric  crest  for  the  adductor ;  fixed  valve  conical  or  spiralj 
Cardinal  formula  010;  ligament  in  a  dcej)  groove,  almost  internal,  parivincular, 
opisthodetic.     Cretaceous. 

Gaprina  d'Orb.  {Gemmellaria  Mun.-Chalm. ;  Gornucaprina  Fiitt.)  (Figs.  771,  772). 


Fio.  771. 

Longitudinal  section  of 
the  lixed  valve  of  Caprina 
adversa,  shovving  cavities  in 
the  inner  .shell  layer. 


Fig.  772. 

Cross-section 
of  the  free  valve 
of  Capritui  mm- 
inunis  Gemmeh, 
showing  parallel 
canals  in  the 
middle  layer. 


Fig.  773. 

Flagioptychus  aguüloni  d'Orb.     Upper  Cretaceous  ; 
Gosau,  Austria.    s/^j. 


Very  inequivalve,  attaclied  by  tlie  apex  of  the  coniform  right  valve.  Left  valve  large, 
spirally  twisted  ;  inner  layer  of  lower  valve  made  up  of  concentric  lamellae  between 
wliich  cavities  are  sometimes  left.  The  middle  layer  of  the  free  valve  traversed  by 
numerous  simple,  wide,  parallel  canals,  extending  from  the  margin  to  the  apex;  tooth 
of  the  attached  valve  well  developed,  a  series  of  depressions  between  the  posterior 
adductor  scar  and  the  margin.  Cenomanian.  The  typical  species,  G.  adversa  d'Orb., 
is  of  large  size. 

Schiosia  Böhm.  Like  Gaprina,  but  the  fixed  valve  somewhat  gyrate  and  the 
canal  syatem  present  in  both  valves.     Cenomanian  ;  Upper  Italy. 

Flagioptychus    Math.    {Sphaerocaprina    Gemm. ;    Orthoptychus    Futt.)    (Figs.    773, 

A  B 


Flagioptychus  aguüloni  (d'Orb.)  (P.  paradoxus  Math.).  Upper  Cretaceous  (Hippurltes  Liniestone);  Le 
Beausset,  Var,  France.  A,  Right.  B,  Left  valve  of  the  same  individual,  seen  from  within,  2/3.  «,  Anterior; 
a'  Posterior  adductor  scar ;  l,  Ligamentary  groove ;  c,  Anterior  tooth  ;  c'.  Posterior  tooth  of  left  valve ; 
d!  Socket ;  s,  Buttress.  .  C,  Section  of  the  small  valve  near  the  margin,  showing  canals  (y)  of  tlie  middle  layer. 
Magnified. 

774).     Right  valve  conical  or  twisted,   attached  ;  left  valve  convex,  with  inciirved 


480 


MOLLUSCA 


PHYLUM  VI 


beak  ;  ligament  as  in  Ghama.  Shell  structiire  like  Gaprina,  biit  tlie  free  valve  with 
canals  in  the  luiddle  layer  ;  tlie  walls  of  the  canals  bifurcate  outwarcl,  forming  in 
section  a  fringe  of  periplieral  minor  cliannels  (Fig.  774,  (7).  Cenomanian  and  Turonian  ; 
Europe. 

Caprinula  d'Orb.  (Chaperia  Mun.-Chalni.)  (Figs.  775,  776).     Right  valve  elongated, 

A  attaclied,  conical  or  incurved  ; 

left  snialler,  gyrate  ;  botli  with 
caiial  System,  the  periplieral 
canals  smaller ;  hinge  as  in 
Gaprina.  Cenomanian  and 
Turonian,  especially  in  Portu- 
gal, Sicily  and  Texas. 

Ichthyosarcolithus  Des- 
marest      {Gaprinella      d'Orb.). 


Fig. '775. 

Caprinula  haylei  Geinm. 
Upper  Cretaceous ;  Ad- 
dauran,  near  Palermo.  1/2 
(after  Gemmellaro). 


Fig.  776. 

Caprinula  boissyi  d'Orb.  Cross- 
section  of  the  lower(^)and  upper 
{B)  valves.  c,  Teeth ;  s,  Septum  ; 
u,  Body  cavity;  x,  Sockets.  2/3 
(after  Wood  ward). 


Fig.  777. 

Mass  consisting  of  Caprotina 
semistriata  and  C.  striata 
d'Orb.,  and  a  smooth  Spliaeru- 
litcs.  Greensand  ;  Le  Mans, 
Sarthe  (after  d'Orbigny). 


Cretaceous.     Gaprotina  d'Orb.  (Fig.  777).      Canals  obsolete,  replaced  in  some  species 
by  cavities.     Neocomian  to  Turonian. 

Goralliochama  White.  Right  valve  conical,  elongated,  attaclied  ;  left  smaller,  with 
incurved  beak ;  anterior  cardinal  tooth  buttressed,  strong  ;  posterior  cardinal  weak  ; 
canals  as  in  Plagioptychus,  bounded  within  by  a  coarsely  cellular  layer  ;  lower  valve 
with  a  prismatic  outer  and  laminar  inner  layer,  separated  by  an  intermediate  cellular 
Stratum.     Cretaceous ;  California. 


Superfamily  6.     RUDISTACAE   (Rudistae,  Lamarck). 

Ghamacea  in  which  the  spirality  of  the  valves  has  been  lost,  the  area  and  ligament 
vertically  suhmerged,  and  the  dorsal  margins  recurved  over  them  so  as  to  bring  the  ligament 
into  a  sub-central  position  above  the  teeth  but  far  beloio  the  dorsal  margin,  where  itfinally 
becomes  obsolete.  The  teeth,  no  longer  forming  a  hinge  but  rather  a  clithrum,  specially 
modißedfor  the  vertical  motion  of  the  operculiform,  left  valve,  in  which  rotation  isprevented 
by  the  protection  of  the  modißed  teeth  into  deey  sockets  in  thefixed  valve ;  the  latter  conical, 
thich ;  pallial  line  simple,  enclosing  the  whole  cavity  ;  shell  structure  specialised  in  two 
very  different  layers ;  sessile,  marine. 

The  prisms  of  the  outer  shell  layer  are  parallel  to  the  long  axis  of  the  valve,  and  are  out 
at  right  angles  by  numerous  tahulae,  which,  together  with  the  upper  margin,  often  hear 
impressions  of  radial  vessels.  The  laminae  of  which  the  inner  layer  is  composed  are  often 
separated  by  cavities  which  recall  the  septa  of  Cyathophylloid  Corals,  or  those  cavities  found 
in  some  oyster  shell s.  In  Hippurites  the  outer  layer  is  traversed  by  a  complex  of  canals. 
The  Rudistacae  are  the  most  peculiarly  modified  of  all  Pelecypods.  Their  relationship  to 
the  Chaniidae  through  Monopleura  and  Caprotina  was  first  recognised  by  C^uenstedt,  and 
afterwards  confirmed  by  Wood  ward,  Bayle,  Zittel,  Munier-Chalmas,  Douville  and  others. 


CLASiS  I 


PELECYPODA 


481 


Formeily  the  groiip  was  referred  to  tlie  most  diverse  connections,  such  as  Biachiomds,  Corals 
Cirripedes,  etc.,  or  placed  in  a  special  class  by  itself.  ' 

The  luajority  of  Rudislids  occur  gregariously  in  hirge  nuuibers,  sometinies  filling  entire 
beds  ;  they  are  often  found  m  their  natural  position,  standing  vertically  on  the  apex  of  the 
attached  valve.  Notwithstanding  their  abundance,  it  is  extremely  difficult  and  often  irapos- 
sible  to  separate  the  two  valves  and  expose  the  interior,  hence  the  hinge  of  many  species  is 
still  only  inij>erfectly  known. 


Family  13.     Radiolitidae  Gray  (emend.). 

Shell  sabstance  wüh  the  external  layer  thick,  prismatic ;  the  internal  thin,  cellulo- 
crystalline  (frequently  destroyed  in  fossilisation) ;  valves  very  unequal,  the  ligamentary 
sitbsidence  usually  marhed ;  free  valves  wüh  two  projections  and  two  somewhat  irregulär 
myophores ;  fixed  valve  with  one  myophore  and  two  sockets ;  summit  of  the  valves  suh- 
marginal  in  the  young,  subcentral  in  the  adult.      Cretaceous. 


a,  h,  RadioUtcs  {IHradiolites)  cornu-pasturis  d'Orb.  Middle  Cre- 
taceous  (Oarentonian) ;  Pyles,  near  Perigeux.  a,  Shell  with  closed 
valves.  B,  C,  The  two  more  tinely  ribbed  vertical  bands.  h,  Interior 
of  larger  valve,  viewed  from  above.  a,  a',  Adductor  scars  ;  m,  Pallial 
line  ;  n,  Space  occupied  by  soft  jmrts  ;  x,  Empty  space  botween  the 
sockets.  1/2  (after  Bayle).  c,  Opercular  valve  of  Ä.  bournoni  (\)esn\.). 
Upper  Cretaceous  (Dordonian) ;  St.  Mametz,  Dordogne.  a,  Anterior ; 
a',  Posterior  myophore  ;  c,  c',  Anterior  and  posterior  processes  of 
clithrum.     1/3  (after  Bayle). 


Fi(i.  779. 


Ujtper 
Shell 


Spliaerulites  angeiodes  Lam 
Cretaceous ;  Gosau,  Austria. 
with  closed  valves,  Vi-  ^.  Opercular 
valve,  1/1.  A,  Sinus  of  hinge;  a,  a', 
Myophores ;  c,  c',  Processes  of  clithnim. 


Radiolites  (Lani.)  Bayle  (Biradiolites  d'Orb.)  (Fig.  778).  Lower  valve  conical, 
erect,  elongated,  vertically  ribbed,  or  made  iip  of  siiccessive  layers  ;  usually  with  two 
somewliat  smooth  bands  exteiiding  from  the  apex  to  the  upper  margin,  which  are 
supposed  by  Douville  to  indicate  the  position  of  siphonal  orifices ;  outer  layer  very 
thick,  composed  of  large  polygonal  cells  or  liollow  prisms  (Fig.  780).  Upper  valve 
operculate,  flat  or  conical,  with  central  or  eccentric  umbo.  The  clithrum  is  formed  by 
two  vertically  projectiiig  striated  processes  (Fig.  778,  c,  c)  fitting  into  sockets  near 
the  outer  wall  of  the  fixed  valve;  next  to  and  outside  of  the  sockets  are  two  large, 


VOL.  I 


2  I 


482 


MOLLUSCA 


PHYLUM  VI 


uneqiial,  slightly  excavated  adductor  scars,  corresi^oiiding  to  two  broad  myophores  in 


the  Upper  valve.     Middle  and  Upper  Cretace- 
ous  ;  Europe  and  Texas. 

Subgenera :  Lapeirousia  Bayle.  The  smootli 
bands  correspond  internally  to  tAvo  prominent 
tubercles.  Synodontües  Pirona.  Has  the  two 
teeth  of  the  upper  valve  fused. 

Sphaerulites  Delam.  {RadioUtes,  Birostrites 
Lam. ;  Jodamia  Defr. ;  Dipilidia.  ?  Agria 
Math.)  (Figs.  779- 
781).  Externally 
like  Radiolites,  but 
without  the  two 
bands;  valves  with 
a  re-entrant  sinus 
between  the  teeth, 
which.  fit  into  sepa- 
rate pits  {dj  d'), 
usually  joined  by  a 
ridge      with      the 


Fio.  781. 


Fig.  780. 


Sphaerulites  foliaceus  Lam.  Carentonian  ;  Ile 
d'Aix,  Charente.  A,  Sinus  of  the  hinge,  a,  a', 
Portion  of  the  outer  shell  layer  Anterior  and  posterior  adductor  scars  ;  d,  d', 
Anterior  and  posterior  grooved  sockets  for  tlie 
processes  of  the  upper  valve  ;  x,  x',  Empty  spaces 
of  the  ligament  pits  ;  y,  Cavity  at  the  inner  end 
of  the  Sinus.     2/3  (after  Goldfuss). 


of  the  lower  valve  of  a  Sphaeru 

Utes  or  Radiolites  showing  the 
hin^Pr  marfrin  of  ^^^8®  hollow  prisnis.  Cretace- 
mner     margin     01   ^^^ .  jj^^^.^  Gargano,  itaiy.    Vi- 

the  sinus  ;  the  two 

depressions  (Fig.  781,  x,  x)  next  the  sinus  were  shown  by  Pethö  to  have  been  the 
seat  of  a  ligamentary  connection  between  the  valves  ;  the  adductor  scars  {a,  a)  resemble 
those  of  Radiolites.     Widely  distributed  in  the  Middle  and  Upper  Cretaceous. 

The  supposed  genera  Diinlidia,  Birostrites  and  Jodamia  are  based  on  internal 
moLilds  of  Radiolites.  The  visible  submersion  of  the  ligament  in  some  Radiolites 
enables  us  to  understand  how  the  stages  shown  by  Hippurites  have  arisen. 


Family  14.     Hippuritidae  Gray. 

Shell  suhstance  of  two  layers,  the  external  porous,  grooved  and  punctate ;  the  inner 
lacunary  and  prismatic ;  exterior  with  sutures  corresponding  to  an  "  anal "  and 
''  hranchial "  inßection,  and  sometimes  with  a  ligamentary  suture ;  clithrum  formed  of 
two  processes  in  the  free  valve,  the  adductors  attached  to  myophores  ;  fixed  valve  with  one 
thin  laminar  process ;  the  adductor  scars  excavated,  the  anterior  adductor  duplex,  forming 
distinct  scars.     Cretaceous. 


Hippurites  Lam.  (Figs.  782-786).  Lower  valve  cylindro-conic,  sometimes  a  metre 
in  length,  attached  by  the  apex,  smooth  or  longitudinally  ribbed,  wdth  three  furrows 
bounding  two  "  columns,"  or  columnar  areas,  extending  from  the  apex  to  the  upper 
margin  {A,  B,  C).  Upper  valve  depressed,  conic,  with  siib-central  umbo,  usually  with 
two  round  or  oval  foramina  ;  outer  surface  showing  pores,  the  apertures  of  short  canals 
which  join  larger  canals  radiating  from  the  beak.  The  thick  outer  layer  of  the  lower 
valve  is  usually  brown-coloured  and  made  up  of  thin  horizontal  strata,  which  are  in 
turn  composed  of  small  vertical  prisms.  The  white  inner  layer  is  porcellanous,  and 
sometimes  contains  vacant  spaces  in  the  lower  part  of  the  shell.  Three  prominent 
folds  are  present,  on  the  inner  side  of  the  shell,  formed  by  the  inbending  of  both 
layers  of  shell,  and  corresponding  to  the  external  grooves  {A,  B,  G).  Of  these  the 
anterior  {A)  is  longer  and  thinner  than  the  others,  which  are  thickened  at  the  internal 
end  and  carry  a  small  tubercle  above.  In  the  two  subgenera,  Orhignyia  Woodward 
{H.  biloculus  Lam.),  and  Batolites  Montfort  (H.  organisans  Laj).),  the  anterior  sinus 
disappears  entirely.  In  Pironaea  Menegh.,  a  number  of  accessory  folds  appear  behind 
the  two  columns.      According  to  Douville,  the  two  posterior  columns  are  homologous 


CLASS  I 


PELECYPODA 


483 


with    tlie    smooth   band«    of   Radiolites,   and    indieate   the   position   of  the   siphons. 
Woodward  supposes  that  tlie  pit  (x)  contaiiied    the  internal  ligarnent  ;    but  so  far, 


'ö\nilUi:|| 


Hippurites  gosaviensis 
Douv.  Upper  Cretace- 
ous ;  Gosau  Valley, 
Austria.     1/2- 


Fio.  783. 

Hipjmrites  oppeli  Douville.  Nefgraben,  near  Russ- 
bach, Salzburg.  A,  B,  C,  Iinpressed  lines  bounding 
convex  vertical  areas  (columns)  corresponding  to  the 
region  of  the  hinge.    1/2. 


Fig.  784. 

Hippurites  organisans 
Montf.  Vertical  section 
of  a  valve  below  the 
living  Chamber,  show- 
ing  the  septa  and  inter- 
septal   cavities  of  the 


middle  layer. 


Vi. 


remains  of  the  ligainent  have  only  been  found  in  the  bottom  of  the  outer  anterior 
sulciis,  where  it  seemed  to  form  a  vertical  band.  The  second  adductor  scar  is  small, 
and  located  between  the  sulciis  and  the  anterior  column  (B).     The  clithruni  of  the 


Hippurites  radiosus  Desm.  Upper  Cretaceous  (Dordonian) ;  Royan,  Charente.  a,  Upper  valve  (^1,  Sinus  of 
the  hinge  •  B  C  Grooves  corresponding  to  anterior  and  posterior  coluinns  of  the  lower  valve  ;  c,  Anterior,  and 
c'  c"  Posterior  processes  of  the  clithrum).  h,  Interior  of  lower  valve  seen  from  above  (^1,  Sinus  ;  B,  C,  Posi- 
tion of  anterior  and  posterior  columns  ;  a,  a',  Adductor  scars ;  d,  Socket  of  anterior,  and  d',  d",  of  posterior 
processes  of  clithrum  ;  u,  Body  Chamber  of  shell ;  x,  Vacant  cavity  near  the  sinus).    2/3  (after  Bayle). 

Upper  valve  is  extremely  difficult  to  prepare,  and  is  known  in  only  a  few  species. 
The  anterior  process  shows  near  its  base  two  tubercles  (a,  «')>  wliich  correspond  to 


484 


MOLLUSCA 


PHYLUM  VI 


the  divided  addiictor  scar 


of  the  lower  valve.  Behind  tlie  anterior  tliere  are  two 
supplemental  processes,  wliich  are  received  into  the 
sockets  d'  and  d"  of  the  lower  valve.  The  species  are 
abimdant  in  the  Middle  and  Upper  Cretaceous,  and  occur 
chiefly  in  littoral  shallow  water  deposits.  The  most 
noted  localities  are  the  Alps  and  Pyrenees,  Provence, 
Charente,  Istria,  Dalmatia,  Greece,  Sicily,  Asia  Minor, 
Persia  and  Algiers. 

Barrettia     Woodvvard.        Cretaceous  ;     Jamaica     and 
Guatemala. 

Superfamily  7.     LUCINACEA  Anton  (emend.). 
„  ,  ,„  Shell    tvith   the   anterior    adductor  scar  narrower,  pro- 

Htppurites  cornu-vacctnum  Goldi.  .  7    7  77  •    7 

UpperCretaceons;Gosau,Austria.    duced   ventrally ;   posterior   scar  shorter,  rounded ;    palhai 
vaTv£'ko:fngVJ"ÄcW,?g   l^ne  simple;  foot  elongate,  suh-clavate ;   hinge  feehle,  teeth 

clithruni  and  relation  of  the  sliell-    radial,  often  obsolete. 
layers.    1/2 


Family  15.     Tancrediidae  Fischer. 

Shell  donaciform,  equivalve,  ivith  an  external  ligament ;  the  margin  of  the  valves 
entire ;  hinge  with  posterior 
and  anterior  laterals,  the  latter 
inconstant ;  cardinals  one  in 
the  left  and  two  in  the  right 
valve,  or  two  in  each  valve. 
Trias  to  Cretaceous,  (?)  Eecent. 

Tancredia  Lycett  {Het- 
tangia  Terq.;  Palaeomya  Zitt. 
and  Goub.)  (Figs.  787,  788). 
Shell  sub-arcuate,  attenuated 
before  the  beaks,  wider  and 
shorter  behind  them ;  obli- 
quely  truncate  and  somewhat 
gaping  posteriorly  ;  a  cardinal  tooth  on  each  side,  and  also  an  elongated  posterior 
lateral.     Trias  to  Cretaceous  ;  niaximum  in  Lias. 

(?)  Meekia  Gabb.     Cretaceous  ;  California.      (?)  Hemidonax  Mörch  {Donacicardium 
Vest),     Recent. 

Family  16.     Unicardiidae  Fischer. 

Shell  cordiform,  equivalve,  closed,  concentrically  striated ;  adductor  scars  elliptical, 
the  anterior  longer;  pallial  line  simple;  margin  of  the 
valve  smooth ;  ligament  external,  parivincular,  seated  in  a 
groove ;  with  a  grooved  hinge-plate  bearing  a  single  obsolete 
cardinal  in  each  valve,  or  none.  Carbon  iferous  to  Cre- 
taceous. 


Fig.  787. 

TaTwredia  securifonnis  (Dunker).    Lower  Lias  ; 
Hettingen,  Lorraine,    i/i  (after  Terqnern). 


Fio.  788. 


Tancredia  (Falaeo- 
viya)  corallina  'Zitt. 
and  Goub.  Coral- 
Rag ;  Glos,  Calvados. 


Rounded,    inflated. 


Fki.  789. 
Unicardium  cxcentricum  d'Orb. 
Kimmeridgian  ;  Cap  de  la  Heve, 
near  Havre.    i/i. 


Unicardium    d'Orb.    (Fig.    789). 
with  incurved  beaks ;    hinge   margin   thin,    with   a  weak 
cardinal  tooth  ;  ligament  deep  seated.     Trias  to  Cretaceous. 

Sealdia  Ryckholt.      Carboniferous. 

Pseudedmondia  Fischer.     Ligament  comjjletely  external. 
Carboniferous. 


CLASS 


PELECYPODA 


485 


Family  17.     Lucinidae  Fleming. 

SheU   substance  porcellanous    or    chalky,   usually  with  inconspicuous    or    dehiscent 
epidermisy  rounded,  variably  sculptured ;  valves  equal^free,  closedy  with  low,  prosocoelous 


Fig.  790. 
Lucina  (  Miltha)  gigantea  üesh.     Eocene  (Calcaire  Grossier) ;  Grignon,  near  Paris.     2/3. 

heahs  ;  adductor  and  pedal  scars  adjacent  or  distinct,  the  lauer  small ;  anterior  adductor 
elongated,  largehj  within  the  pallial  line,  which  is  not  sinuate  ;  area  within  the  pallial 
line  often  granulär  or  punctate  ;  cardinal  area  small,  often  deeply  impressed ;  ligament 
and  resilium  suh-internal,  set  in  a  deep  groove,  but  usually  more  or  less  visible  externally ; 
hinge-plate  distinct ;  lateral  laminae  distant  from  the  cardinals,  anterior  and  posterior 
in  the  right,  vjith  corresponding  sockets  in  the  left  valve ;  cardinal  teeth  radial,  formula 
LlOlO 
ROlOl' 


the  posterior  tooth  larger  and  often  bifid,  but  any  or  all  of  the  teeth  may  be  obsolete 


or  absent.     Silurian  to  Eecent. 

Paracyclas  Hall.    Eounded,  thin-shelled,  concentrically  striated  ;  no  luniile  ;  hinge 
miknown.      Devonian. 

Lucina   Briig.   (Figs.   790-793).     Koimded,  convex  or  lenticular,  usually  with  a 


Fia.  791. 

Lucina  {Myrteä)  columbella  Lani.    Miocene ; 
Steinabrunn,  near  Vienna. 


Lucina  (Proltunna)  prisca  His.    Silurian  ;  Gotlanil. 
Internal  nioiild  (after  Roemer). 


lunule  ;  with  delicate,  concentric,  or  more  rarely  radial  sculpture ;  dentition  usually 
normal,  the  laterals  developed.  Represented  by  upwai-ds  of  300  fossil  and  100  recent 
species.     (?)  Silurian,  Trias  to  Kecent. 


486 


MOLLUSCA 


PHYLUM  VI 


Subgenera  :  Lucina  s.s.  Lam.  1799  {Loripes  auct.)-     Shell  smootli.     Adult  with  the  teetli 

and  posterior  radial  plication  of  the  valves  obsolete. 
Tertiary  and  Receut. 

Prolucina  Dali  (Fig.  792).  Compressed,  arcnate, 
almost  rostrate  ;  the  anterior  side  larger.     Silurian. 

Myrtea  Turton  (Fig.  791).  Rounded,  sub-equi- 
latei'al ;  teeth  and  posterior  fold  present.  Tertiary 
and  Recent. 

CodaJcia  Scopoli.  Compressed,  reticulately  sculp- 
tured.     Tertiär}'  and  Recent. 

Miltha  Adams  (Fig.  790).  Compressed,  nearly 
smooth  ;  laterals  absent,  cardinals  long,  feeble  (3  :  2). 
Tertiary  and  Recent. 

Divariceila  Martens.      Rounded,   inflated,   valves 
ornameiited  with  angular  divergent  grooving.     Ter- 
tiary and  Recent. 
Tertiary  and  Recent. 


Pkacoides  pulchra  (Zitt.  and  Goiib.). 
.  Coral-Rag ;  Glos,  Calvados.    2/,. 


Phacoides  Blainville  (Fig.  793). 

Family  18.     Oorbidae  Dali. 

Shell  differing  from  the  Lucinidae  in  heing  transversely  oval,  thicJc,  with  a  heavy 
hinge  plate,  and  usually  luell-developed  laterals ;   two  or  three  strong  cardinals  in  each 


Pio.  794. 
Gonodun  mellingi  Hauer.     Upper  Trias  ;  Sarize  am  Predil,  iiear  Raibl,  Tyrol.     Vi- 

valve;  the  margin  of  the  valves  denticulate,  and  the  exterior  strongly  sculptured 
external,  the  adductor  scars  oval,  and  not  projecting  into  the  pallial  area. 
Recent. 

This  family  is  an  ofFshoot  of  the  Lucinidae,  with  which  it  is  commonly  united. 
Gonodon  Scliafh.  (Gorhis  p.  p.  auct.)  (Fig.   794).     Rounded,  plump,  concentrically 


ligament 
Trias  to 


striated.      Cardinals 


LlOl 
ROlO 


sometimes    a    weak 


posterior  lateral  present.     Trias  and  Jura. 

Gorhis  Cuv.  {Fimhria  Megerle,  non  Boh.)  (Fig. 
795).  Thick-shelled,  oval,  inflated,  reticulately 
sculptured ;  each  valve  witli  two  short  cardinals, 
and  anterior  and  posterior  laterals  ;  adductor  scars 
similar,  sub^equal.     Jura  to  Recent. 


Corhis  lamellosa  Lam.     Eocene  (Calcaire 
Grossier) ;  Grignon,  near  Paris,    i/j. 


Fio.  79(5. 
Mutiella  coarctata  Zitt.     Tnronian  ;  Gosau,  Austria.     Vi- 


CLASS  I 


PELECYPODA 


487 


Sphaera  Sow.  (Palaeocorhis  Conr.).      Lower  Civl;i(((.us.      Sjihaeriola  Stol.      Trias 

to  Cretaceoiis.     Fimhriella  Stol.  Chalk  of  Britaiii.      Gorbicella  Mor.  and  Lyc.     Jura. 

M'utiella    Stol.    (Fig.    796).  Anterior    cardinal    border    corriigated,    uptiirned ; 

posterior  rectilinear,  horizontal,  witli  a  feeljlc  lalcial  tootli.      Upper  CretrOceous. 


Family  19.     Diplodontidae  Dali. 

Shell  sub-circular  in  outline,  rarely  nestling  and  irregulär  ;  hinge  with  the  laterals 
obscure  or  absent,  and  the  valve  margins  piain  ;  the  adductor  scars  continuous  peripher- 
ally  with  the  pallial  line  ;  soft  parts  like  the  Lucinidae,  but  with  the  external  limb  of  the 
gills  developed,  and  the  anal  foramen  not  tubulär.      (?)  Jura,  Cretaceous  to  Recent. 

Diplodonta  Bronn  (Fig.  797).  Thin-shelled,  orbicular,  convex,  concentrically 
striate  or  pustulose  ;  cardinals  2  :  2,  tlie  left  anterior  and  riglit  posterior  l)iM  ; 
laterals  obscure  or  absent.     Tertiary  and  Recent. 

Ungulina  Daudin.  Nestling  and  often  ir- 
regulär. Felania  Recluz.  Shell  conipressed ; 
feeble  laterals  present.  Axinopsis  Sars  ;  Sphae- 
rella  and  Tenea  Conrad.      Cretaceous  to  Recent. 


Family  20.      Oyrenellidae  Fischer. 


Diplodonta  dilatata  Phill.     Plioceiie  ; 
Hhodes.     Vi- 


Shell    as    in    Diplodonta,    but    loith    a    con- 
spicuous  epidermis ;  pallial  area  smooth ;  pallial 
line  not   sinuate ;    hinge  without   lateral  laminae ;    the  cardinals   like  Diplodonta,   or 
with  two  cardinals  in  each  valve  soldered  to  each   other    dorsally ;    cardinal  formula 

RTmmn'  ^'^^  anterior  left  cardinal  usually  obsolete.      Pliocene  to  Recent,  in  fresh  and 

brackish  water. 

Cyrenoida  Joannis  (Gyrenella  Desh.).      Pliocene  of  Florida,  Recent  in  the  Antilles 
and  West  Africa. 

Joannisiella  Dali.     Hinge  as  in  Diplodonta,  resilium  immersed,  the  larger  cardinal 


)ifid,  the  teeth  not  soldered  above.       Cardinal  formula 


LlOlO 

Roior 


Recent ;  Philippines. 


Family  21.     Thyasiridae  Dali. 

Shell  substance  earthy,  ivith  inconspicuous  epidermis  and  prosocoelous  beaks ;  valves 
equal,  free,  closed,  ivith  piain  margins,  smooth,  or  with  feeble 
concentric  Striae,  and  usually  with  a  radial  posterior  ßexure ; 
adductors  Lucinoid,  pallial  area  often  punctate  ;  ligament  and 
resilium  parivincular,  opisthodetic,  sub  -  external,  seated  in  a 
groove ;  area  impressed ;  hinge  feeble  without  lateral  laminae, 
edentulous,  or  with  an  obsolete  cardinal  tooth  in  the  right  valve. 
Cretaceous  to  Recent. 

Thyasira  Leach  (Gryptodon  Turton  ;  Axinus  Sow.;  Con- 
chocele  Gabb)  (Fig.  798).  Smooth,  thin-shelled,  living  in 
deep  water.     Cretaceous  to  Recent. 

Philis  Fisch,  Lunule  deeply  indented,  projecting  sj^oon- 
like  into  the  cavity  of  the  valves.     Recent. 


Fio.  79S. 

A,  Thyasira  sinuosa  (Don.). 
Miocene ;  Grund,  near  Vienna. 
Vi-  B,  T.  unicarinata  Nyst. 
Oligocene  (Septaria  -  clay) ; 
Freien  wal<le,  near  Berlin. 


Superfamily  8.     LEPTONACEA  Dali. 

37te  incurrent  and  excurrent  openings  between  the  mantle  lohx  "/ 
body,  the  former  anterior. 


'l'l'" 


mh  nl     Ihr 


488 


MOLLUSCA 


PHYLUM  VI 


This  gi'oup  contains  a  great  many  comniensal,  nestling  or  parasitic  forms  ;  if  indepen- 
dent  usually  very  active,  crawling  like  Gastropods  on  a  sub-reptary  foot,  and  witli  the  mantle 
edges  more  or  less  reflected  over  the  valves. 


Family  22.     Leptonidae  Gray. 

Shell  cellulo-crystalline  with  a  periostmcum ;  valves  equal,  free,  smooth-edged,  often 
gaping,  variahly  sculptured ;  adductor  scars  peripheral,  suh-equal ;  pallial  line  simple  ; 
area  ohscure  or  none ;  ligament  parivincular,  opisthodetic,  exter- 
nal,  often  ohsolete ;  resilium  usually  internal,  suh-umhonal  or 
oblique ;  hinge-plate  narrow,  channelled  to  receive  the  resilium ; 
hinge  variable,  typically  consisting  of  one  or  two  radiating 
cardinals  and  a  pair  of  lateral  laminae  in  each  valve,  the 
anterior  laminae  often  ahsent,  and  the  posterior  frequently 
closely  adjacent  to  the  resilium,  simulating  cardinals.  One 
Cretaceoiis,  and  a  niimber  of  Tertiary  and  Recent  species. 


Fio.  799. 


A,  Erycina  pellucida  Lam. 
Calcaire  Grossier ;  Parnes.  B, 
Hinge  of  E.  foucardi  Desh. 
Lower  Bocene ;  Herouval. 
Greatly  enlarged  (after  De- 
shayes). 


Erycina  (Lam.)  Fischer  (Fig.  799)  ;  Kellia  Turton ; 
Pythina  Hinds ;  Lasaea  Leach  ;  Lepton  Turton  ;  Erycinella 
Conrad  ;  Spaniodon  Reuss ;  Fahella  Conrad,  etc.  Tertiary 
and  Recent. 


Family  23.     Galeommatidae  Gray. 


Shell  without  a  perceptihle  epidermis ;  valves  equal,  free,  widely  gaping  ventrally, 
smooth  or  variahly  sculptured ;  adductor  scars  distant,  oval,  reduced ;  pallial  line 
simple ;  ligament  usually  ohsolete,  resilium  internal,  suh-umhonal  or  oblique,  attached 
to  an  excavated  chondrophore  in  each  valve ;  hinge-plate  hardly 
developed ;  laterals  ohscure  or  ahsent ;  one  or  two  cardinal  teeth  in 
each  valve  or  none.     Tertiary  and  Recent. 

Scintilla  Desli.  (Fig.  800)  ;  Galeomma  Turton  ;  Passyia  and 
Sportella  Desh. ;  Hindsiella  Stol. ;  Ephippodonta  Täte  ;  Solecardia 
Conrad,  etc.     Tertiary  and  Recent. 


Family  24.     Ohlamydoconchidae  Dali.  scintuia    paHsiensis 

Desli.  Upper  Eocene ; 
Shell  cellulo-crystalline  without  an  epidermis,  comprising  the  ^f^^TieshaYes)^^'  ^^^ 
prodissoconch  with  narrow,  long,  laminar  accretions,  very  small ; 
valves  wholly  internal,  not  connected,  contained  in  laterodorsal  separate  capsules,  without 
hinge  or  hinge-plate,  not  attached  to  muscles  or  ligament ;  ligament  ahsent,  resilium 
separately  encapsuled  hetween  the  ohsolete  valves,  functionless.     Recent ;  California. 

The  genus  Chlamydoconcha  Dali  is  evidently  the  last  term  in  a  series  beginn ing 
with  forms  like  Lepton,  and  continned  l)y  Galeomma  and  Eyhippodonta,  but  the 
specialisation  has  been  carried  so  far  tliat  it  may  well  be  regarded  as  the  type  of 
a  distinct  family. 

Family  25.     Kelliellidae  Fischer. 

Shell  with  a  periostracum ;  valves  equal,  free,  closed,  smooth  externally  with  piain 
m,argins ;  pallial  line  simple  ;  area  ohscure  or  none  ;  ligament  external,  parivincular ; 
resilium  external  or  slightly  sunken ;  hinge  plate  narrow,  entire,  with  one  or  tioo 
cardinals,  and  a  single  anterior  lateral  placed  ahove  the  anterior  cardinal  teeth.  Tertiary 
and  Recent. 


CLASS  I 


PELECYPODA 


489 


Kelliella  Sars  ;   Lutetia  Desli. ;  (?)  Ällopagus  Stol. ;   Turtonia  Alder. 
Receiit. 

C  Cyclodonta. 


Eocene  to 


Teeth  arched,  sprmging  from  helow  the  hinge  margin,  with  the  hinge-plate  ohscure  or 
absent. 

Superfamily  9.     CARDIACEA  Lamarck. 

Lobes  of  the  mantle  free  behind  the  siphons,  foot  elongate,  geniculate ;  sculpture  of 
the  shell  chiefly  radial ;  cardinal  teeth  conical,  the  lateral  laminae  short,  distant  from  the 
cardinals. 

Family  26.     Cardiidae  Fischer. 

Shell  substance  cellulo-crystalline,  with  the  external  layer  more  or  less  tubulär  ;  valves 
equal,  free,  gaping  slightly  behind,  the  beahs  prosocoelous,  the  margins  usually  serrate  or 
radially  striated ;  adductor  scars  sub-equal,  the  pedal  distinct  and  usually  distant; 
ligament  and  resilium  parivincular,  external,  short,  set  in  a  groove  ;  area  obscure ;  com- 
plete  hinge  armature  consisting  of  an  anterior  and  posterior  lateral  in  the  left,  and  two 

B 


Fio.  801. 
Cardium  %irodiLctum  Sow.     Turonian  ;  St.  Gilgen,  Salzburg,     i/i- 

anterior  and  one  posterior  lateral  in  the  right  valve,  any  or  all  of  which  may  be  absent ; 
cardinal  formula  üöfQi  >  ^^^^  ^ß^^^^  simple,  smooth,  never  bifid,  one  cardinal  in  each  valve 
usually  persistent,  the  others  inconstant.     Trias  to  Recent. 

Cardium  Linii.  (Figs.  801-803).     Cordate,  iiiflated,  radiately  ribhed  or  .striated, 


Fio.  802. 

Protocardia  hifrons 
Reuss.  Turonian; 
Strobl- Weissenbach  am 
Wolfgangsee,    Austria. 

Vi- 


Fio.  803. 

Cardium  (Discors)  discrejxins  Bast.     Miocene 
Dax,  ne.'ir  Bordeaux,     '/i. 


490 


MOLLUSCA 


PHYLUM  VI 


with  prominent  beaks.      Represented  l)y  aboiit  200  recent  and  over  100  fossil  species. . 
Trias  to  Recent. 

A  very  large  nuniber  of  subgenera  aiid  sections  have  been  proposed,  based  chiefly  pn  the 
external  sculpture.     Some  of  the  more  conspicuous  groups  are  the  following  : — 

Protocardia  Beyr.  (Fig.  802).  Cretaceous.  Discors  Desh.  (Fig.  803)  ;  Laevicardium 
Swains.  ;  Serripes  Beck ;  Fragum  Bolten  ;  Papyridea  Swains.  Tertiary  and  Recent. 
Didacna  Eichwald,  estuarine,  leads  toward  the  next  family. 


Family  27.     Limnocardiidae  Stoliczka. 

Like  the   Gardiidae,  biit  thin-shelled,  with    long  nnited  siphons,  a  short  compressed 

foot,  a  pallial  sinus  and  obsolete 
hinge  armature,  living  in 
bracMsh  or  fresh  water.  Ter- 
tiary and  Recent. 


ii 


Fi(i.   804. 


Limnocardiuin  conjungens  Partsch.     Pliocene  (Congeria  Stage) ; 
Brunn,  near  Vienna.     i/i. 


Adacna      Eicbw.        Shell 

elongate  oval,  truncate  behind, 

gaping    at    both    extremities ; 

Siphons     very     long,     pallial 

sinus    deep.       Miocene,     and 

Recent  in  Caspian  Sea. 

Limnocardium  Stol.  (Fig.  804).     Cardinais  weak,  laterals  strong,  distant,  pallial 

sinus   moderate,  shell  closed   anteriorly.      In   brackish  Miocene   beds,  especially  the 

Sarmatic  and  Pontic  horizons  of  Eastern  Europe,  and  in  estuaries  of  the  Aral,  Black 

and  Caspian  Seas. 

Subgenera  :  Prosodacna  Tourn.  (Psüodon  Cob.)  ;  Monodacna  Eicliw.  ;  Ilhiocardimn  Capell. ; 
Arcicardium  Fischer. 

Superfamily  10.     TRIDACNACEA  Menke. 

Soft  parts  rotated  forward  nearly  90°  loith  relation  to  the  valves  as  compared  with 
typical  dimyarian  Pelecypods,  the  anterior  adductor  wanting,  and  the  posterior  nearly 
central  in  the  shell ;  cardinal  teeth  lamellar,  oblique. 


Family  28.     Tridacnidae  Cuvier. 

Shell  very  densely  porcellanous,  with  no  visible  epidermis ;  valves  equal,  free,  with 
a  byssal  gape,  radially  sculptured,  with  serrate  margins  and  prosocoelous  beaks  ;  ligament 
and  resilium  as  in  the  Cardiidae ;  hinge  with  a  single  oblique  cardinal  in  each  valve,  a 
Single  posterior  lateral  in  the  left,  and  two  in  the  right  valve.     Eocene  to  Recent. 

Byssocardium  Mun.-Chalm.  and  Lithocardium  Woodw.,  of  the  Eocene,  are 
perhaps  precursors  of  the  Recent  Tridacna  Brug.  and  Hippopus  Lamarck. 


Superfamily  11.     ISOOARDIAOEA  Dali. 

Lobes  of  the  mantle  closed,  except  for  the  pedal  and  siphonal  openings,  smooth,  double- 
edged  ;  foot  short,  compressed ; .  sculpture  of  the  shell  faint  or  concentric ;  cardinal  teeth 
lamellar,  parallel  with  the  hinge  margin. 


Family  29.     Isocardiidae  Gray. 

Shell  substance  cellulo-crystalline,  the  external   layer   not   tubulate,  with  a  marhed 
epidermis ;  valves  equal,  free,  rotund,  completely   closed,  with  piain  margins  and  pro- 


CLA8S  I 


PELECYPODA 


491 


minent  prosogyrous  heaJcs ;  adductor  scars  sub-equal ;  pedal  scar  adjacent ;  area  not  dis- 
tinctly  limited ;  ligament  and  resilium  external,  parivincular,  set  in  a  deep  groove,  con- 
tiniious  to  the  heaks ;  complete  armature  of  the  hinge  with  an  inconstant  posterior  lateral 
in  each  valve,  and  rarely,  an  anterior  lateral  dose  to  the  cardinals ;  cardinal  formula 

pqYqT)  ihe  teeth  lamelliform,  and  very  variable  in  details  of  form.     Jura  to  Receiit, 

Many  species  have  been  referred  to  this  group  solely  on  account  of  their  having  gyrate 
beaks.  Tlie  Paleozoic  and  many  Mesozoic  species  so  referred  must  be  separated  from 
Isocardia. 

Isocardia  Lam.  (Figs.  805,  806).  Inflated,  smootli  or  concentrically  striated ; 
beaks  distant,  iniich  produced,  prosogyrate.     Jura  to  Receiit 

B 


B'k;.  8UÖ. 
Isocardia  striata  d'Orb.     Portlandian  ;  Cirey,  Haute-Marne  (after  Loriol). 

Meiocardia  Adams.     Keeled,  concentrically  ribbed.     Tertiary  and  Recent. 
?  Glisocolus  Gabb.      Cretaceous  ;  North  America. 


Fio.  806. 
Hinge  of  Isocardia  lunulata  Nyst.     Crag  ;  Antwerp. 

Family  30.     Vesicomyacidae  Dali. 

Shell  as  in  the  Isocardiidae,  hut  with  low  and  inconspicuous  heaks,  the  valves  more 
elongated,  and  the  lunule  delimited  hy  a  sharp  groove;  cardinal  formula  piqiq^q' 
Tertiary  and  Recent. 

Callogonia  Dali.  Pallial  line  deeply  sinuated,  and  a  distinct  anterior  lateral  close 
to  tlie  cardinal  teetli,      Recent ;  abyssal. 

Vesicomya  Dali.  {Gallocardia  auct.,  non  Adams).  Rounded  or  Tapetiform,  com- 
pressed,  or  not  infiated,  witli  low,  inconspicuous,  non -gyrate  beaks.     Eocene  and  Recent. 


D.  Teleodonta. 

The  most  perfected  type  of  modern  teeth,  to  which,  in  addition  to  the  typical  (10101) 
cardinal  series  of  the  ordinary  Teleodesmacea,  there  is  added  in  the  most  specialised  types 
(Veneridae,  Mactridae)  either  a  roughened  area  (Veiius),  a  series  of  extra  cardinals 
(Tivela),  or  accessory  lamellae  (Mactra),  rendering  the  hinge  rnorr  <  ifinent,  or  covvphcdfrd. 


492 


MOLLUSCA 


PHYLUM  VI 


The  hinge  characters  of  the  less  specialised  forms  hardly  differ  from  the  Diogenodonta, 
but  they  are  grouped  here  on  account  of  their  ohvious  aßnities,  as  shown  hy  other 
characters. 

Superfamily  12.     VENERACEA  Menke. 

Teleodonts  with  normal  gills  united  to  form  a  complete  anal  Chamber,  the  mantle 
lobes  free  behind  the  siphonal  region,  sub-equal  adductors,  an  external  parivincular  liga- 
ment  seated  in  a  groove,  and  the  shell  substance  densely  cellulo-cry stalline  with  incon- 

spicuous  epidermis.     Complete  hinge  formula  r^wr — —f. — q-.^-./-. 0^,  of  which  a  large 

part  is  usually  deßcient. 


Family  31.     Veneridae    Leach. 

Valves  equal,  free,  closed,  with  prosogyrous  beaks,  variably  sculptured,  with  the 
margins  more  or  less  dentate,  except  in  the  smooth  species ;  adductor  scars  peripheral, 
pedal  distant ;  pallial  sinus  more  or  less  sinuated,  area  very  distinct ;  resilium  usually 
external,  embraced  by  the  ligament ;  hinge-plate    developed ;  formula  of  the  cardinals 

KÖToToT'  '^'^^^  ^  Single    obsolete    lateral  in  one   valve ;   the  cardinals  frequently  bifid, 
usually  radially 


and  sub-equal  in  size,  except  the  posterior  left  one,  which  is  often 
obsolete  or  obscure ;  supplementary  cardinals  or 
rugosities  are  present  in  specialised  forms.  Jura 
to  Recent ;  maxinuim  in  Tertiary  and  later. 

The  faniily  must  be  divided  into  at  least  four 
subfamilies,  as  follows  : — 

a.  Venerinae :  typical,  with  produced  siphons, 
not  byssiferous,  the  yoimg  not  retained  within  the 
mather  after  leaving  the  egg. 

h.  Circinae  :  with  separate  short  siplions,  cor- 
relative  nearly  simple  pallial  line,  sub  -  internal, 
partially  amphidetie  resilium,  and  compressed  beaks. 

c.  Tapetinae :  with  long  but  partly  separated 
siphons,  a  byssus  present  at  least  in  the  young ; 
hinge  with  no  lateral  teeth,  otherwise  like  the 
Venerinae. 

d.  Gemminae  :  minute  Shells,  with  more  or  less 
separated  siphons,  no  byssus,  obsolete  lateral  laminae, 
and  sheltering  the  nepionic  young  within  the  cavity 
of  the  mother. 

a.  Pronoella   Fisch.  (Pronoe    Ag.,  non  Guer. 

Men.).     Compressed,  pallial  sinus  very  shallow  ; 

a  posterior  lateral  and  tliree  cardinals  in  eacli 

valve.     Jura. 

Like  the  preceding,  but  the  riglit  valve  wdth  only 

two  cardinals,  the  hinder  one  bifid  ;  pallial  sinus  very  shallow.     Cretaceous. 

Dosinia  Scop.  {Artemis  auct.).  Orbicular,  lentiform,  concentrically  sculptured, 
with  a  deep,  well-marked  lunule :  cardinals  3:3;  pallial  sinus  deep,  ascending, 
pointed.     Cretaceous  to  Recent. 

Eocyclina  Dali.  (Cyclina  Desh.).  Cretaceous  to  Recent.  Sunetta  Link  {Meroe 
Sclium.) ;  Grateloupia  Desm.  Tertiary  and  Recent.  dementia  Gray.  Oligocene  to 
Recent. 

Venus  Linn.  (Fig.  808).  Oval  or  rounded,  plump,  cordate,  thick  ;  concentrically 
or  radially  sculptured,  with  denticulate  margins  ;  hinge-plate  broad,  with  tliree 
cardinals  in  each  valve  and  no  lateral  teeth ;  pallial  sinus  short,  angular.     Jura  to 


Fig.  807. 
Cyprimeria  discus  (Math.).     Upper 
Cretaceous  ;  Gosau  Valley,  Austria. 

Cyprimeria  Conr.  (Fig.  807). 


CLASÖ  I 


PELECYPODA 


493 


Recent  ;  represented  by  about  200  fossil  and  as  many  recent  species.     Very  numerous 
siib-divisions  have  been  proposed  ;    Venus  s.s.  is  typified  by  V.  mercenaria  Lam. 


Venus  cinda  Eichw, 


Fig.  808. 
Miocene  ;  Gainfahrn,  near  Vienna. 


Fig.  809. 

Meretrix  semisulcata  Lam. 
Bocene ;  Grignon,  near  Paris, 


Meretrix    Lam.    {Gytherea   aiict.)    (Figs.    809,    810).     Hinge  with  lateral  teeth. 
Macrocallista  Meek  ;  Callocardia  Adams  ;  Saxidomus  Conrad.     Tertiary  and  Recent. 


Meretrix  inciussata  Sow, 


Weinheim,  near  Alzey. 


Fig.  Sil. 

Circe  exiviia 
Hoernes.  Miocene  ; 
Bnzesfeld,  near 

Vienna. 


Tivela  Link.     Hinge  with  supplementary  cardinals.     Miocene  to  Recent. 
h.  Girce  Schiim.  (Fig.  811).     Gafrarium  Bolten.     Umbones  compressed,  sculpture 
often  divaricate,  ligament  immersed.    Tertiary  and  Recent. 

Subgenus  Gouldia  Adams.     Sniall,  concentrically  striated. 
Eocene  to  Recent. 

Ptychomya  Agassiz. 
Cretaceous. 

c.  Paphia  Bolten 
(Tapes  Megerle ;  Pul- 
lastra  Sow.)  (Figs.  812- 
814).  More  or  less 
elongate,  oval,  with 
narrow  hinge  -  plate, 
divergent  and  often 
bifid  cardinals,  no  la- 
terals,  and  deep  pallial 
sinus.  Cretaceous  to 
Recent ;  about  150 
living  species. 


Flu.  Sl-J. 


Paphia  gregaria  Partsch. 
Sarmatian  Stage ;  Wiesen,  near 
Vienna. 


Fig.  813. 

Paphia  (Baroda)  fragilis  (d'Orb.). 
Upper  Cretaceous  ;  Gosau,  Austria. 


494  MOLLUSCA  phylüm  vi 

Of  tlie  nunierous  subgeiiera,  Baroda  (Fig.   813)  and  Iscanotia  (Fig.   814)  Stol.,   from  the 

Cretaceous,  are  remarkable  tbr  their  elonga- 
tioii  and  tlie  ridge-like  form  of  tho  posterior 
Cardinal. 

Onco'phora  Rzehak.    Differs  from  Ta2?es 

in  having  a  very  sliort  pallial  sinus,  and 

the  anterior  addiictor  scar  bounded  by  a 

ridge.      Miocene  brackish-water  beds. 

Fio-  814.  Venempis   Lam.      Cardinal  teeth   2  : 

'  Paphia  (Iscanotia)  impar  Zitt.    Upper  Cretaceous ;       2-3,  stronff  ;  a  borer  or  nestler,  often  de- 

Gosau.  /.im.  T   1-, 

formed.      Tertiary  and  Kecent. 

d.  Gemma  Desli.  ;  Parastarte  Conr.  ;  Psephidia  Dali.  Minute  Shells.  Eocene 
to  Recent. 

Family  32.     Petricolidae  d'Orbigny. 

Valves,  when  not  distorted,  equal,  free,  somewhat  gaping  hehind,  radiately  sculptured 
with  piain  margins  and  inconspicuous  heaks ;  posterior  adductor  scar  larger  tkan  the 
anterior,  pedal  narrow,  elongated,  distinct ;  ligament  and  resilium  external ;  area 
ohscure  or  not  defined  ;  hinge  without  lateral  laminae,  with  two  or  three  small,  usually 
bifid,  radial  cardinal  teeth  in  each  valve.      Cretaceous  to  Recent. 

Petricola  Lam.  (Choristodon  Jonas  ;  Naranaio  Gray)  ;  Petricolaria  Stol. 

The  family  Glaucomyacidäe,  of  estuarine  or  fluviatile  habit,  appears  to  be  related 
to  Petricola,  and  includes  the  Recent  Glaucomya  (Bronn)  Woodward,  and  Tanysiphon 
Benson. 

Superfamily  13.     TELLINACEA  Blainville. 

Siphons  distinct  to  their  hases,  usually  long  ;  ^aZ^m?  line  sinuate  ;  ligament  external, 
seated  on  nymphs ;  hinge  typically  with  an  anterior  and  posterior  lateral  in  each  valve, 
two  radial  cardinals,  of  which  the  anterior  is  commonly  hifid  and  somewhat  pedunculated, 
and  the  posterior,  as  well  as  the  laterals,  often  obsolete. 

Family  33.     Tellinidae   Deshayes. 

Shell  substance  cellulo-crystalline,  with  an  inconspicuous  epidermis ;  valves  slightly 
unequal,  free,  rounded  in  front,  more  or  less  rostrate,  oblique,  and  gaping  behind,  com- 
pressed,  usually  loith  smooth  margins,  low  beaks,  and  variable,  chießy  concentric  sculpture ; 
anterior  adductor  scar  larger,  frequently  irregulär ;  pedal  distinct ;  resilium  embraced  in 
the  ligament,  sub-external ;  area  narrow,  small,  covered  with  a  dark  ejndermis,  or 
frequently  obsolete ;  hinge-plate  narrow,  anterior  laterals  approximate,  posterior  more 
distant  from  the  cardinals,  when  present  ;  cardinal  teeth  small  ;  pallial  sinus  deep, 
discrepant  in  the  opposite  valves.     Jura  to  Recent. 

Tellina  Linn.  Elongated,  the  rostrum  more  or  less  twisted  ;  two  lateral  teeth  in 
each  valve  ;  shell  porcellanous.     Jura  to  Recent. 

Subgenera:  Teilina  s.s.  (Figs.  815,  816);  Tellidora  Mörch  ;  Strigilla  Turton ;  Lincaria 
Conrad  (Areopagia  d'Orb.)  (Fig.  817),  etc. 

Macoma  Leach.  Anal  siphon  long,  branchial  very  short,  hinge  without  laterals  ; 
shell  smooth,  earthy,  less  elongated  than  in  Tellina.     Tertiary  and  Recent. 

Gastrana  Schum.  {Fragilia  Desh.).      Miocene  and  Recent. 

Quenstedtia  Mor.  and  Lyc.  Long,  oval,  obliquely  truncate  behind  ;  beaks  low, 
pallial  sinus  shallow,  only  a  single  cardinal  tooth  present.     Jura. 


CLASS  I 


PELECYPODA 


4Ü5 


Fig.  810. 

Tcllina  rostralina  Desh.     Eocene  ;  Damery, 
near  Epernay. 


Tellina  plaiiata  Lam.     Miocene 
near  Vienna. 


Pötzleinsdorf, 


Fig.  817. 

Tellina  (Linearia)  biradiata  Zittel.     Upper 

Cretaceous  ;  Gosau,  Austria. 


Family  34.     Semelidae  Dali. 


Resembling  the  Tellinidae,  but  with  the  resilium  internal,  often  on  a  distinct  chondro- 
phore,  and  lüith  the  laterals,  when  present,  stronger  and  less  distant.     Tertiary  to  Kecent. 

Semele  Schiim.  (Ämphidesma  Lam.).     Shells  large,  rounded,  thick,  often  conspicu- 
ously  sculptiired ;     100    species.      Tertiary  and 
Kecent. 

Cumingia  Sow.  Small,  tliin,  with  a  spoon- 
like  chondrophore  ;  habit  nestling.  Tertiary 
and  Recent. 


m-^^ 


Fig.  818. 


Ahra  apelina  (Ren.).     Miocene  ;  Grund, 
near  Vienna. 


Scrohicularia  Schum.      Differs  froni  Semele  in 
having  no  lateral  teeth.     Tertiary  and  Recent. 

Ahra  Leach  (Syndosmya  Recluz)  (Fig.  818). 
Smooth,  small,  thin  ;  cardinals  2:2,  an  anterior  and  posterior  lateral  present  ; 
chondrophore  narrow,  oblique,  not  separated  from  the  hinge  line.  Tertiary  and 
Recent  ;  chiefly  in  deep  water. 

Family  35.     Psammobiidae    Dali. 

Shell  as  in  the  Tellinidae,  hut  usually  more 
equivalve  and  less  twisted,  with  more  conspicuous 
epidermis  and  nymphs,  hroader  hinge-plate,  and 
a  wider  posterior  gape ;    lateral  laminae  on  the 


Fig.  819. 

Psammobia  effiisa  Desh.     Eocene  (Calcaire 
Grossier) ;  Farnes, 


•  Fig.  820. 

Psammosolen  (Macha)  deshayesii  (Desm. ).  Calcaire 
Grossier ;  Grignon,  near  Paris,    i/j. 


496 


MOLLUSCA  PHYLUM  VI 


hinge  ivantiiKj^  and  the  cardinals  sometimes  three  in  one  valve ;  li(jament  external  and 
conspicuous  ;  no  defined  area.     Tertiary  and  Recent. 

Psammohia  Lainarck  {Gari  Sclium.)  (Fig.  819).  (?)  Cretaceoiis.  Tertiary  and 
Recent. 

Pliorhytis  Conrad  ;  Asaphis  Modeer  ;  Sanguinolaria  Lam.  ;  Tagelus  Gray  ;  Nova- 
culina  Beiison  ;  Ämphichaena  Phil. ;  Psammosolen  Risso,  witli  subgenus  Macha  Oken 
(Fig.  820) ;  Azor  Leach  ;  and  Heterodonax  Mörcli.     Cretaceons  to  Recent. 

Family  36.  Donacidae  Desliayes. 
Valves  equal,free,  siib-trigonal,  usually  closed,  solid  ;  outer  surface  and  inner  margins 
smooth  or  radially  sculptured,  the  posterior  end  usually  shorter  and  obliquely  sub-truncate  ; 
2Jallial  sinus  similar  in  both  valves ;  resilium  sub-internal,  sometimes  amphidetic ; 
ligament  short,  external,  seated  in  a  deep  groove,  episthodetic ;  hinge-plate  moderately 
developed,  usually  with  a  posterior  and  anterior  lateral  in  the  right,  and  corresponding 

sockets  in  the  opposite  valve;  cardinal  formula  t.q-,qY'  ^^'^  strongest  cardinal  tooth  often 
bifid.     Lias  to  Recent. 

The  resilium  is  chiefly  opisthodetic  and  sub-internal,  but  some  of  the  large  species  have  a 

sniall  Segment  of  the  resilium  separate  from  the  rest, 
wholly  internal,  and  in  front  of  the  beaks. 

Isodonta  Buv.  {Soiverbya  d'Orlj.)      Snb-syniniet- 
rical,  convex,  laterals  strong,  pallial  sinus  deep.  Jura. 
Donax  Linn.  (Fig.  821).      Anterior  side  longer, 
laterals  weak.      Upper  Eocene  and  Recent ;  about 
Piti.  821.  lOÖ  species.     Subgenus  Iphigenia  Schuni.     Recent. 

Donax  lucÄda  Eichw.     Miocene  (Sarmatian  Egeria  Lea.       Lower  Eocene. 

stage);  Wiesen,  near  Vieiina.  ^2)  Hemidonax  Morch  {Donacicardium  Vest). 

Superfamily  14.     SOLENACEA  Lamarck  (emend.). 
Dwellers  in  soft  sea-bottom,  narrow,  elongated,  modified  for  burrowing,  gaping  at 
both   ends ;   foot   elongated,    distally   modified   to  serve  as  a  piston  or   stilt  within  the 
burrow ;  siphons  short ;  hinge  without  lateral  laminae. 

Family  37.     Solenidae  Leach. 

Shell  substance  as  in  Tellina,  but  the  external  layer  showing  its  cellular  structure 
more  clearly  ;  with  a  pronounced  epidermis ;  valves  equal,  free,  usually  truncoAe  at  both 
ends,  and  more  or  less  ineqidlateral,  with  low  beahs,  smooth  margins,  not  rostrate,  smooth 
or  feebly  sculptured ;  adductor  scars  narrow,  elongate,  dorsally  distributed,  pedal  distinct ; 
pallial  sinus  small  in  species  with  anterior  umbones,  and  vice  versa  ;  ligament  and  re- 
silium external,  parivincular,  seated  on  nymphs ;  area  obscure  or  none ;  hinge-plate 
hardly  developed  ;  hinge  often  with  a  thickened  ray  crossing  the  valves  and  serving  as  a 
buttress ;  cardinals  varying  from  one  to  four  in  each  valve,  usually  a  single  slender 
radial  laminar  cardinal  in  the  right,  and  tioo  in  the  left  valve,  with  or  without  one  or 
two  placed  parallel  with  the  hinge  margin,  simulating  laterals;  radial  teeth  usually 
more  or  less  pedunculated,  rarely  bifid.     Devonian  to  Recent. 

The  Silurian  forms  heretofore  referred  to  this  family  do  not  seem  to  belong  to  it,  but 
Palaeosolen  Hall  is  scarcely  distinguishable  externally  from  some  modern  forms  ;  its  hinge, 
however,  is  unknown.  The  species  of  this  family  are  mostly  much  modified  for  a  special 
mode  of  life,  hence  the  variability  in  certain  features,  such  as  the  siphons,  foot  and  ferma- 
ture  of  the  mantle  lobes. 

Solen  Linn.  (Fig.  822),  Scabbard-shaped,  straight,  with  terminal  beaks.  Among 
the  numerous  subgenera  are :  Ensis  Schum. ;  Pharella  Gray ;  Geratisolen  Forbes ; 
Siliqua  Megerle ;  Gultellus  Schum.  (Fig.  823).     Tertiary  and  Recent. 


CLASS  I  PELECYPODA 

Palaeosolen  Hall.      Devoiiian.     Leptosolen  Conrad,      Cretaceous. 


497 


Solen  suhfragilis  Eichw.     Miocene  (Sarma- 
tian  Stage) ;  Pullendorf,  Hungary. 


Fio.  823. 

Cultdlus  gngnonensis  Desh.     Calcaire 
Grossier ;  Grignon,  near  Paris. 


Superfamily  15.     MACTRACEA  Gray. 

Resilium  internal,  seated  on  chondrophores,  left  cardinal  tooth  hifid,  fitting  below  the 
hüo  right  cardinals,  which  are  more  or  less  joined  together  dorsally.  Inner  ivall  of  the 
mantle  hehind  the  siphons  exhibiting  a  laminar  sense  organ. 


Family  38.     Mactridae  Gray. 

Shell  porcellanous,  loith  an  ohvious  epidermis,  usually  rounded-triangular,  with 
smooth  or  concentrically  sculptured  surface,  smooth  margins,  and  prominent  prosogyrous 
heahs ;  valves  eqtial,  'free,  usually  with  a  slight  posterior  gape ;  area  not  limited;  liga- 
ment  variahly  external  or  internal;  resilium  connecting  sub-triangular  chondrophores 
usually  excavated  out  of  the  hinge-plate,  rarely  with  a  prop  or  buttress ;  hinge-plate  well 
developed,  with  tijpically  an  anterior  and  posterior  lateral  in  the  left,  received  into  sochets 
or  paired  laminae  in  the  right  valve,  or  obsolete  ;  cardinals  in  the  right  valve  two,  with 
their  dorsal  edges  usually  soldered  together,  and  one  bifid  or  deltoid  cardinal  in  the 
left,  fitting  beloiv  the  former,  a  delicate  accessory  lamella  often  present  in  either  valve,  or 
all  may  be  more  or  less  obsolete;  siphons  well  developed,  united,  and  usually  with  an 
epidermal  tunic ;  adductors  peripheral,  sub-equal.     Cretaceous  to  Eecent. 

This  group  is  so  large  and  its  extre;nes  so  variable,  that 
it  is  best  divided  into  subfamilies,  as  follows  :  ^  Mactrinae, 
Pteropsidinae,  Lutrariinae,  Zenatiinae  and  ?  Anatinellinae. 


Mactra  Linn.  (Fig.    824). 
separated  by  a  shelly  septum. 


Ligament  and   resilium 
Tertiary  and  Recent 


Subgenera :     Mactra    s.S.,     Coelomactra,     Mactroderma, 
Mactrotoma  Dali  ;  Mactrella  Gray. 


Fk;.  S24. 

Mactra  podolica  Eichw.  Miocene 
(Sarmatian  Stage) ;  Wiesen,  near 
Vienna. 


Fi(i.  825. 
lAUraria  elliptica  Roissy.     Pliocene  ;  Rhodes.     2/3 


Spisula  Gray.     Ligament  and    resilium  not  separated,  the  former  more  or  less 
external.     Cretaceous  to  Recent. 

^  Dcdl,    W.  ff.,  Synopsis  of  a  Review  of  the  Genera  of  Recent  and  Teitiary  Mactridae   and 
Mesodesmatidae.     Proc.  Mal.  Soc.,  1895,  vol.  i. 

VOL.  I  2  K 


498 


MOLLUSCA 


PHYLUM  VI 


Subgenera  :  Hemimactra  Swains. ;  Leptospisula  Dali ;  Cymbophora  Gabb ;  Schizodesma  Gray. 

Mulinia  Gray.  Ligament  and  resilium  immersed  in  the  same  socket.  Miocene 
and  Recent. 

Rangia  Desni.  (Gnathodon  Gray,  non  Goldfuss).  Like  Mulinia,  but  with 
elongated  laterals,  and  the  anterior  lateral  liooked  at  the  umbonal  end.     Estnarine. 

Pteropsis  Conrad.     Eocene.     Xak'om  (Schmidt)  Möller.     Miocene  and  Recent. 

Lutraria  Lam.  (Fig.  825).     Soleniform,  hinge  Mactroid.     Tertiary  and  Recent. 

Schizothaerus  Conr.  {Tresus  Gray) ;  Eastonia  Gray  ;  Heterocardia  Desli.  Tertiary 
and  Recent.     Zenatia  Gray ;  Änatinella  Sow.     Recent. 


Family  39.     Oardiliidae  Dali. 

Shell  cordiform,  with  prominent  prosogyrous  heahs,  small,  thin,  radially  scu^Jtured  ; 

^rior  adductor  scar  impressed  upon  a  radial  myophoric  lamina,  the  anterior  scar 
elongated,  pallial  line  not  sinuated ;  ligament  external,  seated  on  nymphs ;  resilium 
internal  connecting  projeding  chondrophores ;  hinge  without  laterals,  hut  the  cardinal 
teeth  as  in  Mactra.     Tertiary  to  Recent. 

Gardilia  Deshayes.     Eocene  and  Recent. 


Family  40. 


Fig.  826. 

Ervilia  podolica  Eichw.    Miocene  (Sar- 

matian  Stage) ;  Wiesen,  near  Vienna.  Vi- 


Mesodesmatidae  Deshayes. 

Shell  solid  and  heavy,  usually  Donaciform,  with 
erect  or  opisthogyrate  heahs,  otherwise  as  in  the  Mactridae; 
Siphons  naked,  not  united.      Tertiary  to  Recent. 

Mesodesma  Desh.  Tertiary  and  Recent.  Mac- 
tropsis  Conr.  Eocene.  Ätactodea  Dali  (Paphia 
Lam. ;  Eryx  Swains.)  ;  Davila  Gray ;  Anapella  Dali. 
Recent.  Ervilia  Turton  (Fig.  826).  Tertiary  and 
Recent.     Gaecella  Gray.     Recent,  fluviatile. 


E.    ASTHENODONTA. 

often  essehtially  Mactroid,  hut  usually  degenerate  or  ohsolete,  owing  to  modi- 
fications  induced  hy  the  hurroiving  hahit. 


Superfamily  16.     MYACEA  Menke  (emend.). 

Burrowing,  long  siphoned,  frequently  inequivalve  Pelecypods,  usually  with  the  mantle 
lohes  largely  united  helow,  more  or  less  united  siphons,  and  degenerate  hinge  apparatus. 


Family  41.     Myacidae  Wood  ward. 

Shell  suhstance  cellulo-crystalline,  earthy,  with  a  conspicuous  epidermis ;  valves  un 
equal,  more  or  less  elongate,  rounded  in  front 
and  gaping  hehind ;  adductor  scars  suh- 
equal ;  pallial  line  sinuated;  shell  margins 
piain ;  area  ohsolete  or  none ;  ligament  and 
resilium  internal,  opisthodetic,  attached  in 
the  left  valve  to  a  projeding  chondrophore 
merging  with  the  dorsal  margin  hehind,  and 
in  the  right  valve  to  an  inconspicuous, 
usually  suh-umhonal  chondrophore;  hinge 
edentulous ;  siphons  united,  with  a  horny 
tunic,  not  wholly  retradile.  Tertiary  and 
Recent. 


Fig.  827. 


Mya  arenaria  Linn.     Pleistocene  (Glacial  Deposits) 
Bohuslän,  Sweden. 


CLASS  I  PELECYPODA  499 

Mya  Liiiii.  (Fig.  827).     Smooth  externally.     Tertiary  and  Recent. 

Siibgenera  :  Platyodon  Conrad.  Surface  dccussated,  siphou  with  horny  appendages. 
Cryptomya  Conrad.  Small,  the  pallial  line  discrepant  in  the  two  valves.  Sphenia  Turton. 
Minute,  byssiferous,  nestling.     Tugonia  Gray.     Tertiary  and  Recent. 


Family  42.     Oorbulidae  Fleming. 

Shell  small,  much  as  in  Mya,  hut  the  pallial  line  feeble  or  obsolete,  the  ligament 
usually  suh-external,  separated  from  the  resilium,  which  is  internal,  alivincular  and 
amphidetic ;  the  chondrophore 
is  received  into  a  socket  of  the 
opposite  valve,  not  merged  with 
the  valve  margin ;  hinge  lüith 
one  or  two  sub-umhonal  pro- 
jecting  teeth,  and  rarely  ohscure 
traces  of  laterals  ;  the  posterior 
gape  inconspicuous ;  siphons 
short,  united,  naked,  wholly 
retractile.     Trias  to  Recent. 


Fio.  828. 


Corbukt  (Bicorbula)  gallica  La  in. 
Calcaire  Giossier;  Damery,  near 
Epernay,  France.     Hinge,  i/i. 


Fio.  829. 

A,  Corbula  carinata  Duj. 
Miocene;  Pötzleinsdorf,  oear 
Vienna.  B,  C.  angjisUUa  Sow. 
Upper  Cretaceous ;  Gosau. 


Corbula  Lam.  (Figs.  828, 
829).     Small,  ovate,  rostrate,  very  inequivalve,  the  riglit  valve  convex,  larger,  with  a 
prominent  tooth   in   front  of  the   pit  for  the  resilium,  left  valve  with  a  flattened 
chondrophore,  and  usually  a  posterior  tooth.     Trias  to  Recent. 

Subgenera  :  Erodona  Daudin  {Azara  d'Orb.  ;  Potamomya  Sow. ).  Pallial  sinus  obsolete, 
fluviatile.  Pleistocene  and  Recent.  Bothrocorbula  Gabb.  With  a  lunule  deeply  indented 
into  tlie  cavity  of  the  valves.     Tertiary  and  Recent.     Corhulamella  Meek.     With  an  anterior 

myophore.     Cretaceous.     Aniso- 
Ä  thyris   Conr.    (Pachydon  Gabb). 

Pliocene.  Paramya  Conr. ;  Cor- 
hulomya  Nyst.  Tertiary  and 
Recent. 

Family  43.     Saxicavidae 

Gray. 

Shell  substance  as  in  Mya  ; 
epidermis  conspicuous ;  valves 
equal,  free,  rüde  and  often 
irregulär,  more  or  less  elon- 
gated  and  gaping,  not  fully 
covering  the  animal ;  adductor 
scars  often  irregulär,  the  pallial 
line  discontinuous  or  irregulär, 
the  sinus  distinct ;  shell  mar- 
gins  smooth;  area  obsolete; 
ligament  and  resilium  external, 
parivincular,  seated  on  strong 
nymphs,  sometimes  widely  ex- 
tended  ;  hinge  without  laterals^ 
with  few  feeble  or  obsolete  sub- 
umbonal  cardinals.  Creta- 
ceous to  Recent. 

Saxicava    Fleuriau    (Glycimeris    Schum.  ;    Hiatella    Daudin ;    Byssomya    Cuvier ; 
Agina  Turton).     Hinge  edentulous  in  the  adult,  with  one  or  two  caitlinals  in  the 


Panope  msnardi  Desh 
of  valves.     B,  Internal  mould 


Miocene;  Vienna  Basin.     A,  Dorsal  view 
C,  Hinge-plate  seen  from  above,  V2' 


500 


MOLLUSCA 


PHYLUM  VI 


yoiing,  boriiig  in  the  softer  rocks.  Tertiary  and  Recent.  Subgenus  Panomya  Gray 
{Chaenopea  Mayer). 

Panope  Menard  ^  {Glycimeris  Lam.  1799,  non  Da  Costa)  (Fig.  830).  Large,  gaping 
widely  behind  and  sliglitly  in  front ;  siirface  concentrically,  or  feebly  sculptured  ;  an 
obscnre  tootli  in  eacli  valve.     Cretaceous  to  Recent. 

Gyrtodaria  Daudin  (Glycimeris  Lam.  1801,  non.  Schum.).  Solenoid  witli  strong 
epidermis.     Pliocene  and  Recent. 


Family  44.     Gastrochaenidae  Gray. 

Shell  suhstance  as  in  Saxicava ;  valves  equal,  widely  gaping  in  front ;  adductor  scars 
unequal,  the  anterior  smaller  ;  pallial  sinus  deep,  margins  simple ;  area  none ;  ligament 
and  resiliurn  external,  parivincular ;    hinge  with  a  single  obsolete  cardinal  or  wholly 

edentulous ;  animal  frequently  forming 
an  external  protective  tuhe  to  Supplement 
its  hurrow,  hut  to  which  it  is  in  no  way 
attached.     (?)  Permian.     Trias  to  Recent. 

This  group  Stands  between  the  Myacea 

and  Adesmacea,  verging  on  the  latter.    Many 

of  its  characters  are  adaptive,   and  are  re- 

peated  in  the  Ensiphonacea,    but  niorpho- 

c»^™=e.    mS   l°gi'=='"y   it«   ■■•'l'^ttons   to   the   Saxicavidae 

-  -  seem  close. 


Fio.  832. 
Gastrochaena      deslong- 


Fio.  831. 


Gastrochaena  angusta  Desh 
Eocene  (Sables  moyens) 
Valmandois,  near  Paris. 


Jura;  Baiin,  near  Cracow 
Internal  mould  of  burrow 
including  one  of  the 
valves,  i/j. 


Gastrochaena        Spengler        ( Ghaena 

Retzius  ;  Rocellaria  Blainv.)  (Figs.   831, 

832).    Bores  cylindrical  or  pear-shaped  cavities  in  rock,  sliell,  or  coral.    Trias  to  Recent, 

Fistulana  Brug.     Secretes  calcareous  tiibes  wliich  stand  upriglit  in  the  sand  or 

mud.     Recent. 


Superfamily  17.     ADESMACEA  Blainville. 

Gills  with  direct  and  reßected  laminae,  long,  united,  extended  into  the  hranchial 
siphon ;  posterior  adductor  usually  in  front  of  the  visceral  ganglion,  anterior  adductor 
external  to  the  cavity  of  the  valves,  exerted  in  a  contrary  sense  to  the  posterior  muscle ; 
hinge  margin  reflected,  edentulous ;  ligament  obsolete ;  a  myophoric  process  extending 
freely  into  the  valve  from  the  sub-umbonal  cavity. 


Family  45.     Pholadidae  Fischer. 

Shell  cellulo-crystalline,  with  a  thin  epidermis ;  valves  more  or  less  gaping  in  front 
and  behind,  with  inconspicuous  beahs   and   reticulate,  often  spinöse   sculpture ;    in  the 


Fig.  833. 
Fholas  levesquei  Watelet.     Eocene  ;  Ciiise  de  la  Mothc 


adult  supplemented  by  accessory  shelly  pieces,  always  attached  to  the  valves,  but  rarely  by 
an  exterior  shelly  tube  like  that  of  the  Gastrochaenidae  ;  the  antero-dorsal  margins  more 
or  less  extensively  reßected,  the  postero-ventral  approximated ;  pallial  line  sinuated,  area 

^  Erroneously  written  Panopea  by  many  authors. 


CLASS  I 


PELECYPODA 


501 


none ;  liijament  and  resilium  usually  ahsent,  an  obsolete  remnant  of  the  redlium  and 
chondrophore  sometimes  present  in  the  left  valve.     (?)  Carbon it'eroiis,  Jura  to  ßecent. 

Pholas  Linn.  (Fig.  833).  Surface  divided  by  grooves  iiito  areas  which  ofteii  have 
diverse  sculpture  ;  the  adult  ofteii  provided  with  accessory  shelly  plates,  eacli  of  which 
when  seated  in  front  of  the  beaks  has  been  named 
a  "  protoplax  "  ;  when  above  the  beaks,  "  mesoplax"  ; 
when  behind  the  beaks  between  the  valves,  "  nieta- 
plax " ;  and  when  between  the  valves  ventrally 
(Martesia),  "  hypoplax."  A  calcareous  septum, 
secreted  after  the  conipletion  of  the  burrow,  and 
occupying  the  pedal  gape  of  the  valves,  is  called 
the  "callum."  The  addition  of  these  plates  and 
appendages  dnring  growth  so  changes  the  appear- 
ance  of  the  shell  that  old  and  yoiing  stages  have 
frequently  been  described  as  specifically  or  even 
generically  distinct.  Typical  Pholads  date  from 
the  Jura.     Many  subgenera  have  been  named. 

Turnus  Gabb  (Fig.  834).  Cretaceous.  Martesia  Leach  (Fig.  835).  Carboniferous 
to  Eecent.  Jouannetia  Desni.  Tertiary  and  Recent.  Teredina  Lani.  Valves  in  the 
adult  stage  soldered  together  and  to  a  thick  adventive  calcareous  tube.     Eocene. 


Fig.  834. 

Turnus  (Xylopha- 
gella)  ehgantulus 
Meek.  Upper  Cre- 
taceous ;  Idalio. 
Enlarged  (after 
Meek). 


Martesia  conokka 
Deshayes.  Eocene ; 
Auvers,  near  Paris. 

Vi. 


Shell 


Family  46.     Teredinidae  Scacclii. 

reduced,  equivalve,  auriculate,  widely  gaping,  the  valves  apposited 
ventrally  only  on  the  surface  of  a  parietal  tubercle ;  adductor 
scars  unequal,  thd  anterior  marginal  very  small ;  pallial 
line  coincident  with  the  valve  margins ;  a  styloid  myophore 
projecting  from  the  cavity  of  the  beaks ;  mantle  secreting  a 
calcareous  lining  to  the  burrow;  pallets  variable  in  form,  the 
valves  without  attached  accessory  shelly  plates ;  area  none ; 
hinge  margin  reflected,  edentulous ;  ligament  absent  or 
obsolete;  anterior  adductor  degenerate^  attached  on  the 
anterior  edges  of  the  valves^  and  covered  only  by  the  mantle ; 
animal  boring,  chießy  in  wood.  Carboniferous  (?) ;  Jura  to 
Recent. 


Pallets  simple,  spatuli- 
Pallets    articulated, 


Fir,.  836. 

A,  Valves  of  the  recent  Teredu 
norvegica  Spengl ;  inner  and  outer 
Views.  B,  Fallet  of  Xylotrya  sp. 
C,  Fallet  of  Teredo  sp.  D,  Gasts 
of  borings  of  Teredo  tounmU  Leym. 
Eocene ;  Kressenberg,  Bavaria. 


Teredo  Linn.  (Fig.  836,  A,  G). 
form.     Jura  to  Recent. 

Xylotrya   Leach   (Fig.    836,    B). 
bipinnate.     Tertiary  and  Recent. 

The  name  Teredolites  Leymerie,  has  been  proposed  for 
the  casts  of  borings  of  fossil  Teredos  (Fig.  836,  D).  The 
problematical  genus  Polorthus  Gabb,  from  the  American 
Cretaceous,  has  been  referred  to  this  family.  The 
Paleozoic  species  are  known  only  by  burrows,  which  are 
of  somewhat  doubtful  origin. 


Vertical  Range  of  the  Pelecypoda. 

Two  sniall  forms  of  bi valve  shells,  Fordilla  and  Modioloides,  occurring  in  the 
Lower  Canibrian  of  New  York  State,  have  been  doubtfully  referred  to  Pelecypods, 
but  are  more  probably  to  be  regarded  as  Brauch iopod  Crustaceans.  Aside  from  these 
fossils,  whose  molluscan  affinities  must  be  considered  as  highly  problematical,  Pelecypods 


502  MOLLUSCA  phylum  vi 

are  unknown  from  strata  geologically  older  than  the  St.  Peter  sandstone,  whicli  is  of 
early  Ordovician  age.  Here  appear  suddenly  several  genera  of  the  Modiolopsidae,  and 
this  family,  together  with  the  Anibonychiidae,  Cyrtodontidae,  and  Ctenodontidae, 
attain  the  acme  of  their  development  during  the  Middle  and  Upper  Ordovician.  In 
the  Silurian  a  considerable  number  of  bivalves  is  observable,  as  many  as  eighty 
species  having  been  distinguished  in  the  fauna  of  the  small  island  of  Gotland  alone. 

A  very  marked  difference  in  geological  ränge  is  perceptible  among  the  three  Orders 
into  which  the  class  is  divided.  The  Prionodesmacea,  including  most  of  Neumayr's 
Palaeoconcha,  are  pre-eminently  characteristic  of  the  Paleozoic  faunas.  Of  the  forty- 
two  families  referred  to  this  order,  no  less  than  seven  occur  in  the  Ordovician,  and 
eighteen  in  the  Silurian,  to  which  seven  are  added  during  the  Devonian,  only  three  in 
the  Carboniferous,  and  one  in  the  Permian.  From  these  ancient  Stocks  only  seven 
Prionodesmacean  families  are  evolved  during  the  whole  of  the  Mesozoic,  and  but  two 
in  the  Tertiary,  while  three  are  Eecent. 

The  Order  Änomalodesmacea  is  represented  in  the  Paleozoic  solely  by  its  radical, 
the  Pholadellidae  ;  eight  of  its  sixteen  families  originate  in  the  Mesozoic  and  Tertiary, 
and,  with  the  exception  of  the  Pholadellidae  and  Pleuromyacidae,  all  have  endured 
until  the  present  time.     Only  one  family  appears  to  be  exclusively  Eecent. 

The  Teleodesmacea  are  distinctively  modern,  although  foreshadowed  in  the  Paleo- 
zoic by  Cypricardian,  Lucinoid  and  Allodesmid  radicals  (the  Solenoid  radical  is  still 
questionable).  Of  forty -seven  families  thirty  can  be  first  definitely  recognised  in  the 
Mesozoic,  twelve  originate  in  the  Tertiary,  two  are  exclusively  recent,  and  only  a  single 
one  can  be  traced  continuously  from  the  Paleozoic  to  the  recent  fauna. 

Of  the  Prionodesmacean  families,  lO'ö  per  cent  survive  ;  of  the  Teleodesmacean  71 
per  cent ;  and  of  the  Anomalodesmacean  88  per  cent.  If  it  were  not  for  the  mortality 
among  the  Chamacea  and  Rudistacae,  the  ratio  of  survival  among  the  Teleodesmacean 
families  would  be  95  per  cent.  Of  105  families  which  have  been  discriminated  during 
the  whole  history  of  the  class,  76,  or  about  72*3  per  cent,  are  represented  in  the 
existing  fauna.  Families  have  originated  in  the  various  geological  epochs  as  follows : 
Ordovician  9,  Silurian  11,  Devonian  9,  Carboniferous  3,  Permian  1,  Trias  13,  Jura  14, 
Cretaceous  18,  Eocene  15,  Miocene  and  Pliocene  3,  Pleistocene  and  Recent  6.  From 
this  it  appears  that  the  development  of  the  group,  judged  by  the  increase  of  families, 
was  most  intense  during  the  Silurian,  thereafter  rapidly  decreasing  until  the  Trias, 
then  gradually  increasing  until  the  Cretaceous,  after  which  the  rate  of  differentiation 
again  rapidly  declined.  It  is  noted  that  in  the  Paleozoic  the  Pelecypods  form  about 
one-quarter  of  all  the  moUusks  known  from  this  era ;  in  the  Jura  and  Cretaceous 
about  one-half,  and  in  the  Tertiary  about  one-third  of  this  number. 

The  Ordovician  and  Silurian  are  especially  characterised  by  the  presence  of 
Taxodont,  Palaeoconch,  and  the  older  forms  of  Schizodont  Pelecypods.  The  Cardio- 
lidae,  Pterineidae,  Ambonychiidae  and  Modiolopsidae  are  common  to  both  the  Silurian 
and  the  Devonian. 

The  Devonian  has  no  families  solely  characteristic,  but  the  brackish-water  Car- 
diniidae,  the  Megalodontidae,  Trigoniidae,  Pinnidae,  Pectinidae  and  Mytilidae  first 
take  rise  in  this  period,  and  the  sinupalliate  Ällorisma  is  the  first  Pelecypod  showing 
clear  evidence  of  retractile  siphons. 

The  Carboniferous  is  marked  by  the  appearance  of  Parallelodon  and  its  allies, 
the  Limidae  and  Ostreidae,  and  some  precursors  of  the  Lucinacea  and  Pholadacea. 
The  Pernidae  and  Gastrochaenidae  make  their  advent  in  the  Permian ;  but,  on  the 
whole,  the  Carboniferous  fauna  persists  throughout  this  period.  In  the  Trias,  however, 
important  changes  take  place ;  many  old  genera  disappear,  and  such  forms  as  the  Limop- 
sidae,  the  true  Uniones,  Spondylus,  Dimya,  the  Pleuromyacidae,  Pholadomyacidae, 
Astartidae,  Lucinacea,  Cardiidae  and  Corbulidae  enter  upon  the  scene. 

During  the  Jura,  genuine  Arcidae,  Änomia,  Eligmus,  various  Anatinacea,  Cyrena^ 
Diceras,  Isocardia,  and  the  Teleodont  Veneridae,  Tellinidae,  Donacidae  and  Pholadacea 


CLASS  I  PELECYPODA  503 

arc  initiated.  The  cliaracter  of  the  Cretaceous  is  strongly  influenced  ]jy  tlie  aberrant 
and  sliort-livcd  Chamacea  and  Rudistids.  The  Mutelidae,  Pandoridae,  Clavagellidae, 
Poromyacidae,  Crassatellitidae,  Cryptodontidae,  Petricolidae,  true  Solens,  the  Mac- 
tridae  and  Saxicavidae,  also  take  their  origin  during  this  period. 

With  the  beginning  of  the  Tertiary  a  gradual  approxiniation  to  present  conditions 
takes  place.  The  Rudistae  have  disappeared,  the  Dysodonts  are  on  the  decline,  and 
the  Teleodesniacean  types  on  the  increase.  Nunierous  Anatinacea,  Leptonacea,  Tridac- 
nidae,  Callocardiidae,  Senielidae,  Mesodesmatidae  and  Myacidae  appear.  At  the  close 
of  the  Eocene,  the  wide  distribution  of  many  types  now  characteristic  of  warm- 
ternperate,  or  tropical  waters  begins  to  be  restricted  ;  and  during  the  Miocene  the 
faunal  boundaries  of  mollusks  depending*  upon  temperature  conditions  are  laid  down 
nearly  on  existing  lines. 

The  following  table  indicates  more  ejcactly  the  geological  ränge  of  the  families  of 
Pelecypods  according  to  oiir  present  information  : — 


[Tabl: 


504 


MOLLUSCA 


PHYLUM  VI 


Families. 

1 

i 

i 
1 

1 

!   d 

CS 

i 

1-5 

1 

i 

6 

1 

Order  1.  Prionodesmacea 

A.  Palaeoconcha 

1.  Soleniyacidae . 

2.  Solenopsidae  . 

3.  Vlastidae 

4.  Grammysiidae 

5.  Cardiolidae      . 

6.  Antipleuridae 

7.  Praecardiidae . 

B.  Taxodonta 
Superfamily  1.  Nuculacca 

8.  Ctenodontidae 

9.  Nuculidae 

10.  Ledidae  . 

Superfamily  2.  Arcacca 

11.  Parallelodontidae    . 

12.  Cyrtodontidae 

13.  Limopsidae     . 

14.  Arcidae  . 

C.  SCHIZODONTA 

Superfamily  3.  Pteriacea 

15.  Pterineidae     . 

16.  Lunulicardiidae 

17.  Ambonycliiidae 

18.  Pinnidae 

19.  Conocardiidae 

20.  Pernidae 

21.  Pteriidae 

22.  Myalinidae      . 

23.  Vnlsellidae     . 

Superfamily  4.   Ostraeea 

24.  Ostreidae 

25.  Eligmidae 

Superfamily  5.  Naiadacea 

26.  Cardiniidae     . 

27.  Megalodontidae 

28.  Unionidae 

29.  Mutelidae 

30.  Etheriidae       . 

Superfamily  6.    Trigoniacea 

31.  Lyrodesmidae 

1 
i 

^""^ 

- 

1 

!   _ 



i 

! 
i 

i 
'■"' 

1 

! 

■ 



[ 

' 

— 

.. 

— 

1      1 

■ 

~ 

32.  Trigoniidae     . 

1 

1 

!i 

i      1 

CLASS  I 


RANGE  OF  THE  PELECYPODA 


505 


Families. 


s 

O     I     Ä 


D.  ISODONTA 

Superfamily  7.  Pectiih 

33.  Pectinidae 

34.  Spondylidae 

35.  Dimyidae 

36.  Limidae . 
Superfamily  8.  Anomiacea 

37.  Anoraiidae 

E.  Dysodonta 
Superfamily  9.  Mytüacea 

38.  Modiolopsidae 

39.  Mytilidae 

40.  Dreissensiidae 


Order  2.  Anomalodesmacea 
Superfamily  1.  Anatinacea 

A.  Eusiphonia 

1.  Pleuromyacidae 

2.  Pholadellidae . 

3.  Pholadomyacidae 

4.  Anatinidae 

5.  Periplomatidae 

6.  Thraciidae 

7.  Myochamidae . 

B.  Adelosiphonia 

8.  Pandoridae 

9.  Lyonsiidae 

10.  Lyonsiellidae . 
Superfamily  2.  Ensiphonacea 

11.  Clavagcllidae  . 

12.  Euciroidae 
Superfamily  3.  Poromyacea 

13.  Poromyacidae 

14.  Cuspidariidae 


506 


MOLLUSCA 


PHYLUM  VI 


Families, 


Order  3.  Teleodesmacea 

A,  Fantodonta 

1.  Allodesmidae . 

B.  DiOGENODONTA 

Superfamily  1.  Cypricardiaeea 

2.  Pleurophoridae 
Superfamily  2.  Astartacea 

3.  Curtonotidae  . 

4.  Astartidae 

5.  Crassatellitidae 
Superfamily  3.   Cyrenacca 

6.  Cyrenidae 

7.  Sphaeriidae     .  , 
Superfamily  4.   Gardüacea 

8.  Carditidae 

Superfamily  5.  Chamacca 

9.  Diceratidae      . 

10.  Chamidae 

11.  Monopleuridae 

12.  Caprinidae 

Superfamily  6.  liudistacea 

13.  Radiolitidae    . 

14.  Hippuritidae  . 
Superfamily  7.  Lucinacea 

15.  Tancrediidae  . 

16.  Unicardiidae  . 

17.  Lucinidae 

18.  Corbidae 

19.  Diplodontidae 

20.  Cyrenellidae   . 

21.  Thyasiridae    . 

Superfamily  8.  Leptonacea 

22.  Leptoiiidae     . 

23.  Galeommatidae 

24.  Chlamydoconchidae 

25.  Kelliellidae     . 
C.  Cyclodonta 

Superfamily  9.   Gardiacea 

26.  Cardiidae 

27.  Limnocardiidae 

Superfamily  10.    Tridacnacea 

28.  Tridacnidae     . 


CLASS  I 


RANGE  OF  THE  PELECYPODA 


507 


Families. 

1 

o 

a 
.2 

Devonian. 
Carboniferous. 

1 

i 

i 

9 

i 
1 

i 
i 

1 

Superfamily  11.  Isocardiacea 

29.  Isocardiidae    . 

30.  Vesicomyaciidae 

D.  Teleodonta 
Superfamily  12.    Veneracea 

31.  Veneridae 

32.  Petricolidae    . 
Superfamily  13.   Telliimcea 

33.  Tellinidae 

34.  Senielidae 

35.  Psammobiidae 

36.  Donacidae 
Superfamily  14.  Solenacea 

37.  Solenidae 
Superfamily  15.  Mactracea 

38.  Mactridae 

39.  Cardiliidae      . 

40.  Mesodesmatidae 

E.  ASTHENODONTA 

Superfamily  16.  Myacea 

41.  Myacidae 

42.  Corbulidae 

43.  Saxica-vidae     . 

44.  Gastrochaenidae      . 

Superfamily  17.  Adesmacea 

45.  Pholadidae      . 

46.  Teredinidae     . 

? 

— 

- 

^__^ 

_ 

_ 

?.. 

1 

?.. 

^^^ 

■■■" 

— 

?.. 

[The  text  for  the  preceding  chapter  on  Pelecypods  was  revised  for  the  first  edition  of  this 
work  by  Dr.  William  H.  Dali,  of  the  United  States  National  Museum,  and  is  here  reproduced 
with  comparatively  few  changes  proposed  by  himself  and  Dr.  R.  S.  Bassler. — Editok.] 


508  MOLLUSCA  phylum  vi 

Class  2.    SCAPHOPODA  Bronn.i 

(Cirrhohranchiata  Blainville  ;  Solenoconchia  Lacaze-Duthiers ; 
Prosopocephala  Stoliczka.) 

Aquatic,  marine^  hilaterally  sijmmetrical  moUusks,  profeded  hy  an  external, 
tubulär,  somewhat  curved  and  fapering  shell,  open  at  both  ends,  the  concave  side 
of  which  is  dorsal ;  the  shell  secreted  by  a  mantle  of  the  same  shape,  the  larger, 
anterior  opening  of  which  is  provided  with  a-  circidar  muscidar  thicJcening,  the  smaller 
opening  serving  as  outlet  for  organic  waste  and  genital  products.  Mouth  furnished 
with  a  radula,  borne  on  a  cylindrical  snout,  and  surrounded  by  a  rosette  of  leaf-like 
appendages  ;  a  düster  of  numerous  exsertile  filaments  (captacula)  sprhiging  from  its 
base.  Otocysts  present,  but  no  eyes  or  tentacles.  Foot  rather  long,  conical,  with 
lateral  lobes,  and  adjacent  to  the  snout  ventrally. 

GUIs  are  wanting,  the  gener al  surface  assuming  respiratory  fundions.  Liver 
large,  bilateral;  intestine  strongly  folded,  the  anus  ventral  and  rather  anterior, 
genital  and  kidney  orifices  adjacent  to  it.  Heart  rudimentary,  with  a  single  Chamber. 
Nervous  System  with  well-developed  ganglia  united  by  commissures.  Reprodudion 
without  copulation,  the  sexual  products  voided  through  the  right  kidney. 

Scaphopods  are  without  exception  marine,  and  for  the  most  part  inhabit 
deep  water.  There  are  few  littoral  species.  They  live  embedded  in  mud  or 
sand,  with  only  the  smaller  end  of  the  shell  projecting  above  the  surface. 
Their  food  consists  chiefly  of  Foraminifera  and  similar  organisms,  captured 
by  the  filamentary  captacula. 

The  tubulär,  curved  shell,  open  at  both  ends,  is  characteristic  of  the  class, 

the  tubulär  shells  of  certain  Gastropods  and  Cephalopods  being  invariably 

closed  at  the  smaller  end.     Some  tubicolous  worms  (Serpulidae)  form  a  similar 

shell,  but  it  is  composed  of  two  layers  only,  instead  of  three  as  in  Scaphopods, 

the  growth  is  more  irregulär,  and  its  microscopic  structure  very  different. 

The  shell  of  Scaphopods  increases  by  successive  increments  at  the  larger 

end,  and  at  the  same  time  loses  by  wear  and  absorption  at  the 

smaller  end.     The  posterior  slits  or  notches  occurring  in  some 

species   are   therefore  formed  by  resorption  of   the  previously 

solid  shell  wall,  and  have  a  genesis  whoUy  different   from   the 

slits  or  fissures  of  Pleurotomaria,  Fissurella,  and  other  Gastropods. 

Various    genera  described   as   Scaphopods  have  since  been 

found  to  belong  to  the  Serpulidae.     Such  are  Pyrgopolon  Montf. 

(Fig.   837),  from   the   Maestricht   of   Belgium,    also   known   as 

/g\  Entalium  Defr.,  and  Pharetrium  König ;  and  Hamulus  Morton 

\>J^  {Falcula  Conrad),  of  the  American  Cretaceous.     The  Cambrian 

Fig.  837.         geuus  Spirodentolium  Walcott,   in   which    the    shell    has    spiral 

Pyrgopolon mosat  Striae,  is  at  present  too  imperfectlv  known  to  lustify  its  refer- 

Montf.  UppsrCre-  i.j.i.cii  ^  iT»«-n 

taceous;  Belgium.   ence  to  the  bcaphopods,  or  even  to  the  Mollusca. 

1  Literature  (see  also,  .linder  the  head  of  Mollusca,  antea) :  Deshayes,  G.  1\,  Anatomie  et 
monographie  du  genre  Dentale.  Mem.  Soc.  Hist.  Nat.  Paris,  1825,  vol.  in.— Lacaze-Duthiers,  H.  de, 
Histoire  de  l'organisation  et  du  doveloppement  du  Dentale.  Ann.  des  Sei.  Nat.,  1856-57,  ser.  4,  vols. 
vi.,  wm.—Sars,  M.,  Om  Siphonodentalium  vitreiim,  en  ny  Slaegt  af  Dentalidernes  Familie. 
Universitets-Prograra,  Christiania,  1861. —Stoliczka,  F.,  Palaeontologia  Indica.  Cretaceous  Fauna 
of  Southern  India,  vol.  ii.,  18Q7-Q8.— Gardner,  J.  S.,  Ou  the  ^Cretaceous  Dentaliidae.  Quar. 
Journ.  Geol.  Soc.  London,  1878,  vol.  xxxiv.  —  Kovalevsky,  A.,  I^tude  sur  rembryogenie,  etc.,  dn 
Dentale.     Ann.    Mus.  Hist.  Nat.   Marseille,  1882-83.      Zoologie,   Mem.   No.    I.—Plate,  L.,  Über 


CLASS  ir 


SCAPHOPODA 


509 


Family  1.     Dentaliidae  Gray. 

Scaphopoda  havimj  a  conical  foot  ivith  an  encircling  sheath  expanded  laterally  and 
interrupted  dorsally.  Shell  tubulär,  curved,  regularly  tapering  throughout,  not  contracted 
anteriorly,  sculptured  or  smooth.     Ordovician  to  Eecent. 

DentaUum  Linn.  (Figs.  838,  839).     Characters  those  of  tlie  family.     Beginning 
with  a  few  species  in  the  Ordovician,  the  number  increases  slowly  until  the  Cretaceous. 
A  great    acceleration    then  ensues,  wliich  continues   to   the  present. 
About  275  fossil  and  150  recent  species  known.    Various  autliors  liave         * 
attempted  to  subdivide  tlie  genus  upon  cliaracters  of  tlie  posterior  slit 
of  the  Shell,  but  this  has  proved  to  vary  widely  even  aniong  individuals. 
The  following  siibgenera  based   upon  the    system  of   sculpture    and 
shape  of  the  tube  appear  more  stable  : — 

DentaUum  s.  str.  (Fig.  839).    Shell  with  streng  longitudinal  ribs,  apical 
notch  Short  or  wanting.     Eocene  to  Recent. 

Antalis  Adams  {Entalis,  Gray  non  Sovvb,  ; 
Entaliopsis  Newton  and  Harris)  (Fig.  838, 
A).  Shell  with  longitudinal  riblets  or  Striae 
at  least  in  the  young  ;  apex  with  a  short 
ventral  slit  and  a  sheath.  Cretaceous  to 
Recent. 

HeteroscMsma  Simr.  With  longitudinal 
riblets  and  a  dorsal  slit.     Recent. 

Fissidentaliuvi  Fischer.  Large  and  solid, 
with  many  longitudinal  ribs  or  Striae  ;  a  long 
ventral  slit  usually  present.  Eocene  to  Re- 
cent. Schizodentalium  Sowb.,  in  which  the 
slit  is  interrupted  into  a  series  of  holes,  is 
probably  a  modificatiou  of  this  group. 

Gra-ptacme  Pils,  and  Sharp.  Surface  with 
close,  fine  longitudinal  Striae  near  apex  only, 
or  throughout.     Tertiary  and  Recent. 

La^videntalium  Cossni.  Arcuate,  smooth, 
with  growth-lines  only,  circular  in  section, 
apex  simple  or  notched.    Silurian  ?  to  Recent. 

Rhahdus  Pils,  and  Sharp.  Smooth,  thin, 
glossy,  nearly  straight,  sub  -  circular  in 
section,  apex  entire.     Recent. 

Upisiphon  Pils,  and  Sharp.     Small  and  very  slender,  smooth,  thin,  the  apex  generally 
with  an  inserted  tube.     Oligocene  to  Recent. 

Compressidcns  Pils,  and  Sharp.     Small,  much  tapering,  vertically  compressed,  smooth. 
Eocene  to  Recent. 

Lohantale  Cossm.     Shell  compressed,  with  two  internal  longitudinal  ribs.     Eocene. 

Fustiaria  Stol.  (Fig.  838,  B,  C).     Shell  with  a  very  long  and  linear  ventral  cleft  posteriorly. 
Cretaceous  to  Recent. 

Plagioglypta  Pils,  and  Sharp.     Surface  with  extremely  oblique,  sinuous,  encircling  Striae 
{D.  undulatum  Münst.).     Carboniferous  to  Trias. 


A,  D.  (Antalis)  kickxi  Nyst.  Oli- 
gocene ;  Weinheim,  near  Alzey.  B, 
D.  {Fustiaria)  lucida  Desh.  Eocene  ; 
Cuise  la  Mothe.  i/i-  6',  Posterior 
portion  of  same  enlarged,  showing 
slit. 


Fio.  839. 

DentaUum  sex- 
angulare  Lam. 
Pliocene ;  Asti, 
Italy. 


Family  2.     Siphonodentaliidae  Simroth. 

Scaphopoda  having  the  foot  either  expanded  distally  in  a  symmetrical  disk  with 
crenate  continuous  edge,  or  simple  and  vermiform,  without  developed  lateral  processes. 
Shell  small  and  generally  smooth,  often  contracted  towards  the  mouth.  Cretaceous  to 
Recent. 


den  Boa  und  die  Verwandtschaftsbeziehungen  der  Solenoconchen.  Zool.  Jahrb.,  Abteil,  für  Anat. 
und  Ontog.,  1892,  vol.  v.  [Biltliography,  pp.  38i-dS6.]— Simroth,  H.,  Mollusca,  in  Bronn's 
Classen  und  Ordnungen  des  Tierreichs,  vol.  iii.,  1893-95. — Pilsbry,  H.  A.,  and  Sharp,  B.,  Scapho- 
poda, in  Tryon  and  Pilsbry's  Manual  of  Conchology,  1897-98,  vol.  xvii. — Bellini,  li.,  Revisione 
delle  Dentaliidae  dei  terreni  terziari  e  quaternari  d'  Italia.      Palaeont.  Ital.,  1909,  vol.  xv. 


510  MOLLUSCA  phylum  vi 

Althougli  tliis  family  is  usually  cliaracterised  by  a  sinall  smootli  sliell,  tlie  essential 
difference  from  tlie  Dentaliidae  is  in  the  form  of  tlie  foot.      Typical  forms  of  Gadulus 

appear   in   the  Cretaceous ;   the  remaining 

A  B  c  D     genera  are  Tertiary  and  Recent. 

^|(-v  f  /  Entalina  Monts.     Shell  Dentalium-WkQf 

J|j||/S  Ml     largest  at  the  apertnre,  thence  tapering  to 

/nlj^         fl      ^C\        %S       ff       *^^  ^"^^^ '  ^^^^^g^y  ribbed,  and  angular  in 

iM  I  ■  Im       ^        tf      section  near  tlie  apex.     Miocene  to  Recent. 

^         /l  ^(^       hi  Siphonodentalium  Sars  (Pulsellitm  Stol. ; 

^^  SipJionentalis    Sars).       Shell    an     arcuate, 

Fig.  840.  sliglitly  taperiiig    tube,  circular  in  section 

A,  Cadulus  (Polyschides)  denticulatus  Desh.    Cal-    qj.  nearly  SO,  and  smooth  externallv.     Apex 

caire  Grossier ;  Damery,  near  Epernay.    B,  Cadulus  ''  ^       •     ^^        ^•^    •    ^      ^^  f    ^ 

{DiscUdßs)    hifissuratus    Desh.      Calcaire    Grossier;    rather    large,    typicaliy   sllt    mto    lobes,    but 

?oSN"oTteS,o.'''ASr.S™c.   Tor.-   sometime-s  simple.     Pliocene  to  Recent. 

tonian ;  Monte  Gibbio,  near  Sassuolo,  Italy.  Cadulus     Phil.     {Gadus     Desh.  ;      Gadüa 

Gray;  Heionyx  Stimp.)  (Fig.  840,  G,  D). 
Shell  tubulär,  circular  or  oval  in  section,  swollen  near  the  middle  or  anteriorly,  con- 
tracting toward  the  apertnre.     Cretaceous  to  Recent. 

Typical  forms  with  simple  anal  orifice  appear  first  in  the  Cretaceous,  Dischides, 
Jeffr.  (Fig.  840,  B),  with  two  lateral  slits,  and  Polyschides  Pils.  (Fig.  840,  Ä),  with 
several  notches,  appear  in  the  Eocene.     All  continue  to  the  present  time. 

Olass  3.    AMPHINEURA  von  Ihering.i 

Aquatic,  marine^  hilaterally  symmetrical  moUusks,  with  the  head  partially  or  not 
differentiated ;  in  form  worm-like  with  a  ventral  groove  or  none,  or  oval,  flatternd, 
with  a  foot  adapted  for  creeping.  Nervous  System  consisting  of  an  oesophageal  ring 
with  ganglia  and  four  longitudinal  cords,  two  ventral  and  two  lateral ;  no  cephalic 
eyes,  tentacles,  or  otocysts.  Gillspaired  or  many,  posterior  or  lateral ;  mouth  anterior, 
usually  with  a  radula  ;  anus  posterior,  median.  External  surface  with  a  series  of 
eight  shelly  plates,  or  stiffened  tvith  calcareous  spicules. 

Order  1.     APLACOPHORA  von  Ihering. 

Body  vermiform,  with  a  ventral  groove,  the  skin  elsewhere  heset  with  calcareous 
spicules  ;  no  dorsal  shelly  plates  in  the  adult. 

This  is  a  degenei|ate  group,  represented  in  the  Eecent  fauna  by  about  a 
dozen  genera  belonging  to  two  families — Chaetodermatidae  and  Neomeniidae. 
Fossil  remains  are  unknown. 

Order  2.     POLYPLACOPHORA  Blainville.     Chitons. 

Amphineura  protected  by  a  dorsal  series  of  eight  shelly  valves  and  an  encircling 
girdle  ;  with  differentiated  head,  and  a  ventral  sole  or  foot  adapted  to  creeping  ;  gills 

^  Literature  :  Ihering,  H.  v. ,  Vergleichende  Anatomie  des  Nervensystems  und  Phylogenie  der 
Mollusken,  1877.— Dali,  W.  H.,  On  the  Genera  of  Chitons.  Proc.  U.S.  Nat.  Museum,  1881,  vol. 
iv. — Hubrecht,  A.  A.  W.,  A  Contribution  to  the  Morphology  of  the  Amphineura.  Quar.  Journ. 
Microscop.  Soc,  1882,  vol.  xxii.  [Bibliography,  pp.  226,  227 .}— Hochebrune,  A.  T.  de,  Mono- 
graphie des  especes  fossiles  appartenant  ä  la  classe  des  Polyplaxiphores.  Ann.  Sei.  Geol.  1883,  vol. 
xiv. — Pruvot,  Q.,  Sur  l'organisation  de  quelques  Neomeniens  des  cotes  de  France.  Arch.  Zool. 
Exper.  et  Gener.  [2],  1891,  vol.  ix.  [Bibliography,  pp.  702,  703.]— PiMry,  H.  A.,  Monograph  of 
the  Polyplacophora.  In  Tryon  and  Pilsbry's  Manual  of  Conchology,  vols.  xiv.  and  xv.,  1892-93. 
— Broili,  F.,  Die  Fauna  der  Pachycardientuffe  der  Seiser  Alp.  II.  Scaphopoden  und  Gastropoden. 
Palaeoutogr.,  1907,  vol.  liv. 


cLAss  III  AMPHINEURA  511 

numerous,  occupying  the  groove  hetween  foot  and  girdle  ;  radula  present,  heterodont  ; 
sexes  separate. 

The  exteriial  covering  in  the  Polyplacophora,  or  Chitons,  consists  of  eight 
valves  bound  together  by  an  encircling  flexible  band  called  the  girdle.  The 
anterior  or  head-plate  (Fig.  841,  A,  below)  is  invariably  semicircular,  with  the 
apex  or  mucro  at  the  middle  of  the  straight  margin ;  the  six  succeeding  plates 
are  generally  Square  (Fig.  842,  below),  with  the  apex  posterior  on  the  median 
line  ;  and  the  posterior  or  tail-valve  (Fig.  841,  B)  is  semicircular  or  subcircular, 
with  apex  varying  in  position  from  in  front  of  the  middle  to  the  hind  margin. 
All  of  the  plates  are  composed  of  two  layers — an  outer  porous  layer,  the 
tegmentum,  and  an  inner  porcellanous  one,  the  articulamentum.  In  most  of  the 
lower  Chitons  these  layers  are  coextensive  and  have  smooth  edges;  but  in 
the  higher  forms  the  articulamentum  projects  beyond  the  outer  layer  into  the 
substance  of  the  girdle,  in  which  it  is  firmly  inserted.  These  projections  at 
the  outer  or  peripheral  margin  are  termed  Insertion  plates.  They  are  generally 
slit  or  notched  into  so-called  "  teeth,"  which  may  be  either  smooth  and  sharp 
along  the  edge,  or  crenulated  (pectinated).  Insertion  plates  serve  the  function 
of  binding  the  valves  firmly  to  the  girdle. 

The  anterior  margin  of  each  valve  except  the  first  one  invariably  shows 
two  projections  of  the  articulamentum  called  sutural  laminae  (Figs.  841,  B, 
842),  which  pass  under  the  rear  margin  of  the  next  anterior  valve,  thus  pre- 
venting  vertical  displacement  of  the  series.  The  tegmentum  is  traversed  by 
a  multitude  of  fine  canals  which  terminate  at  the  surface  in  minute  sense 
Organs.  The  cavities  of  the  latter  in  dry  or  fossil  valves  are  visible  as  fine 
quincuncial  punctations.  In  the  highest  Chitons  a  certain  number  of  these 
sense  organs  have  become  enlarged  and  modified  into  eyes,  easily  recognised 
as  pigmented  dots  in  recent,  and  small  pits  in  fossil  specimens. 

Polyplacophora  make  their  appearance  as  early  as  the  Ordovician  ]  they  are 
rare  in  the  >  Silurian  and  Devonian,  but  somewhat  more  abundant  in  the 
Carboniferous.  None  of  the  Paleozoic  genera  is  known  to  continue  into  the 
Mesozoic,  but  the  Eoplacophora  are  replaced  by  types  more  related  to  modern 
Chitons  (^Mesoplacophora).  Members  of  the  most  specialised  suborder,  Teleo- 
placophora,  first  appear  in  the  Eocene,  although  they  doubtless  arose  earlier. 
About  twenty  Paleozoic,  five  or  six  Mesozoic,  and  fifty  Tertiary  species  have 
been  described.  Recent  forms  number  several  hundreds.  A  good  many 
species  supposed  to  be  Chitons  have  been  based  upon  barnacle  valves,  fish 
scales,  and  other  fragments.  The  recently  described  Duslia  insignis  Jahn  is 
apparently  a  Crustacean ;  certainly  not  a  member  of  the  Polyplacophora. 

Three  suborders  are  recognised,  according  as  the  insertion  plates  are 
absent,  or  if  present,  unslit  (Eoplacophora) ;  developed,  smooth,  and  slit  into 
teeth  (Mesoplacophora) ;  or  both  slit  and  pectinated  (Teleoplacophora). 

Suborder  A.     EOPLACOPHORA  Pilsbry. 

Polyplacophora  with  the  tegmentum  coextensive  with  the  articulamentum^  or  with  the 
latter  projecting  in  smooth,  unslit  insertion  plates ;  gills  posterior. 

Family  1.  Gryphochitonidae  Pilsbry. 

Insertion  plates  ahsent,  sutural  laminae  small ;  one  or  both  end-valves  with  the 
terminal  margins  elevated  ;  form  elongated  and  narrow.     Paleozoic. 


512 


MOLLUSCA 


PHYLUM  VI 


Helminthochiton   Salter.      Valves    tliin,    mucro   subcentral,    low;    end-valves   not 
elevated  terniinally.     Silurian. 

Priscochiton  Billings.      Similar  in  the  non-sinnous  liead-valve,  biit  beaks  of  tlie 
valves  greatly  produced  backwards.     Ordovician. 

Gryphochiton  Gray  (Fig.  841).     Elongated,  with  small  beaks  and  very  small  sntural 
laminae ;    terminal  margins   of   end-valves  strongly  elevated  ;    tail-valve    witli  low, 
decurved  mucro  behind  the  middle,      Carboniferous. 

Pterochiton  Carp.  (Änthracochiton  Rochebr,).  Elon- 
gated, the  valves  strongly  beaked  and  laterally  excavated  ; 
tail-valve  with  depressed  post- median  mucro  and  no 
posterior  sinus,  anterior  valve  with  the  front  margin 
elevated,  sutural  laminae  large.      Carboniferous. 

Gymatochiton  Dali  (Protalochiton  Rochebr.).  Oval, 
elevated  and  granulär,  the  valves  short  and  wide,  with 
small,  low  sutural  laminae  and  distinct  lateral  areas ; 
mucro  of  posterior  valve  post-median,  elevated.  Permian. 
Proholaeum  Carp.  Elongated,  elevated  ;  valves  very 
strongly  beaked,  the  pleura  projecting  beyond  the  jugal 
tract ;  anterior  valve  sinuate  in  front,  posterior  valve 
unknown.      Devonian. 

Ghonechiton  Carp.     Median  valves  as  in  Gryphochiton  ; 


Fig.  841. 


Gryphochiton  priscus  (Münst.). 
Carboniferous ;  Tournay,  Belgium. 
J,  Anterior  and  threeintermediate    posterior     valve    with      the     mucro 
valves.    B,  Posterior  valve,  ventral    ^  ,  •       y^        ,      7 

and  dorsal  aspects.    Vi-  thrown  backward,  as  m  Cryptoptax. 

Carboniferous. 

Loricites    Carp.      Somewhat  like  the   Recent   Lorica,  Init 

without  Insertion  plates.     Carboniferous. 

Family  2.     Lepidopleuridae  Pilsbry. 


Fig.  842. 


Lepidopleurus 
(Sandb.).  Miocene ;  Wald- 
böckelheim,  near  Creuz- 
nach,  Germany.  A  median 
and  a  posterior  valve.     '-^/i. 


Insertion  plates  ahsent,  or  present  and  unslit ;  end-valves 
with  the  terminal  margins  never  elevated;  form  oval  or  oblong. 
Tertiary  and  Recent. 

Lepidopleurus  Risso  {Leptochiton  Gray)  (Fig.  842).  Small,  oval ;  Insertion  plates 
entirely  absent,  sutural  laminae  small ;  girdle  minutely  scaly  or  chaffy.  Eocene  to 
Recent. 

Hanleyia  Gray.  Like  the  last,  except  that  the  anterior  valve  has  an  unslit  Insertion 
plate,  and  the  girdle  is  spiculose.     Champlain  to  Recent. 

Hemiarthrum  Carp.  Both  anterior  and  posterior  valves  with  smooth  unslit 
Insertion  plates,  the  others  lacking  them  ;  girdle  downy,  with  small  sutural  pores. 
Rec^int. 

Ghoriplax  Pils.  Valves  partly  immersed  in  the  minutely  granulöse  girdle,  all  with 
thin,  smooth  Insertion  plates.     Recent. 


Suborder  B.     MESOPLACOPHORA  Pilsbry. 

Insertion  plates  developed,  slit,  not  vertically  grooved  or  pectinated  outside. 


Family  1.     Ischnochitonidae  Pilsbry. 

Valves  having  the  inner  layer  well  covered  hy  the  outer.  Surface  of  intermediate 
valves  divided  into  lateral  and  central  areas  hy  a  diagonal  rib  (pften  indistinct),  extending 
from  the  beah  to  each  anterior  outer  angle  of  tegmentum ;  or  when  this  is  not  clearly  the 
case,  the  posterior  valve  has  a  crescentic  series  of  well-developed  teeth ;  all  valves  with 
slits.     Eocene  to  Recent. 


CLASs  III  AMPHINEURA  513 

Two  subdivisions  of  this  family  are  recognised,  according  as  tlie  anterior  and  side 
slits  correspond  in  position  witli  ribs  on  the  extenial  surface  or  not.  Among  the 
genera  included  under  tlie  first  section  {Callistoplacinae)  may  be  mentioned  the  follow- 
ing  : — CallistocJiiton,  Nuttalina,  and  Callistoplax  Carpenter  ;  Graspedochiton  Shuttle- 
worth  ;  and  Geratozona  Dali.  Representatives  of  the  second  subfamily  {Ischnochitoninae) 
are  as  foUows  : — Schizoplax  Dali ;  Tonicella,  Trachydermon,  and  Dinoplax  Carpenter  ; 
Gallochiton  and  Ischnochiton  Gray  ;  Ghaetopleura  Shuttleworth. 


Family  2.     Mopaliidae  Pilsbry. 

Valves  externally  divided  tijpically  into  central  and  lateral  areas,  the  posterior  valve 
with  a  sinus  hehind,  one  or  two  slits  pn  each  side  of  it  or  none ;  intermediate  valves  each 
with  a  Single  slit ;  teeth  smooth,  sharp,  often  with  thickened  edges  on  the  outside ;  girdle 
more  or  less  hairy.     Pleistocene  and  Recent. 


This  family  comprises  the  following  genera  : — Mopalia  and   Plaxiyhora  Gray 
Placiphorella  Carpenter  ;  and  Placophoropsis  Pilsbry. 


Family  3.     Acanthochitidae  Pilsbry. 

Valves  more  or  less  immersed  in  the  smooth  or  hairy  girdle,  the  tegmentum  therefore 
much  smaller  than  the  articulamentum ;  the  exposed  surface  divided  into  a  narrow  dorsal 
and  wide  latero-pleural  areas,  the  latter  formed  hy  the  union  of  the  lateral  and  pleural 
areas  of  typical  Ghitons.  Insertion  teeth  sharp,  rarely  smooth;  posterior  valve  either 
slit  like  the  head-valve,  or  having  a  posterior  sinus ;  head^valve  usually  with  five  slits, 
intermediate  valves  singly  slit     Body  never  vermiform.     Pliocene  to  Recent. 

The  following  representatives  are  to  be  cited  : — Acanthochites  Risso  ;  Spongiochiton 
Carpenter ;  Katharina  and  Amicula  Gray ;  Gryptochiton  Midd.  and  Gray. 

Family  4.     Oryptoplacidae  DalL 

Elongated  or  vermiform  Ghitons  with  small  valves;  insertion  and  sutural  plates 
strongly  drawn  forward,  sharp  and  smooth ;  the  anterior  valve  with  three  to  flve  slits,  the 
others  with  one  slit  on  each  side,  or  none;  tail-valve  having  the  mucro  far  posterior, 
insertion  plate  continuous  hehind ;  girdle  very  thick  and  wide. 

This  is  a  highly  specialised  branch  of  a  low  groiip  of  Chitons,  unknown  in  the 
fossil  State.  Gryptoplax  Blainville  {Ghitonellus  Lam.),  and  Ghoneplax  Carpenter,  are 
examples. 

Suborder  C.     TELEOPLACOPHORA  Pilsbry. 

All  valves,  or  the  first  seven,  with  insertion  plates  cut  into  teeth  hy  slits ;  the  teeth 
sharply  sculptured  (^ectinated)  outside  hy  fine  vertical  grooves. 

Family  1.     Ohitonidae  Pilsbry. 
Gharacters  those  of  the  suhorder.     Tertiary  and  Recent. 

The  family  is  illustrated  by  the  following  genera,  of  which  only  the  first  two  occur  in 
the  fossil  condition  : — Ghiton  Linne  ;  Trachyodon  Dali ;  Eudoxochiton  Shuttleworth  ; 
Tonicia,  Schizochiton,  Enoplochiton  and  Onithochiton  Gray  ;  Acanthopleura  Guilding  ; 
Lorica  Adams  ;  Loricella  and  Liolophura  Pilsbry. 

VOL.  I  2  L 


514  MOLLUSCA  phylum  vi 


Olass  4.    GASTROPODA.    Snails/ 

MoUusks  with  distind  head,  soled  or  more  rarely  fin-like  foot,  and  undivided 
mantle,  which  latter  usually  secretes  a  univalve,  spirally  wound,  or  saucer-shaped  shell 

Gastropods  difFer  from  Pelecypods  in  having  a  more  or  less  distinctly 
marked  head,  which  usually  bears  tentacles,  eyes,  and  ears,  and  contains  a 
large  cerebral  ganglion.  The  ventral  aspect  of  the  creature  is  commonly 
formed  by  a  broad  foot ;  but  in  the  Heteropoda  this  is  modified  into  a  vertical, 
laterally  compressed  fin ;  and  in  the  Pteropoda  it  is  represented  by  two  wing- 
like  swimming  membranes  near  the  head.     The  base  of  the  foot  is  sometimes 

^  Literature  (see  also  under  head  of  Mollusca,  antea) :  Ihering,  H.  v.,  Vergleichende  Anatomie 
des  Nervensystems  und  Phylogenie  der  Mollusken.  Leipsic,  1877. — Koken,  K,  Über  die  Ent- 
wickehmg  der  Gastropoden  vom  Kambrium  bis  zur  Trias.  Neues  Jahrb.  f.  Mineral.,  1889,  supplem. 
vol.  vi. — Quenstedt,  F.  A.,  Petrefaktenkunde  Deutschlands.  Gastropoden,  vol.  vi.,  1881. — Simroth, 
H.,  Gastropoda,  in  Bronn's  Klassen  und  Ordnungen  des  Tierreichs,  1896. — Troschel,  H.,  Das 
Gebiss  der  Schnecken,  zur  Begründung  einer  natürlichen  Classification,  vols.  i.,  ii.  Berlin,  1856-78. 

A.  On  Paleozoic  Forms. — Billings,  E.,  Palaeozoic  Fossils.  Geol.  Surv.  Canada,  1865-74,  vols.  i., 
ii. — JaTcowlew,  F.,  Die  Fauna  einiger  oberpaläozoischer  Ablagerungen  Russlands.  Mem.  Comite 
Geol.,  1899,  vol.  xv.,  No.  3. — Koken,  E.,  Die  Gastropoden  des  baltischen  Untersilurs.  Bull.  Acad. 
Imp.  Sei.  St.  Petersb.,  1897,  vol.  vii.,  No.  2. — Koninck,  L.  G.  de,  Faune  du  calcaire  carbonifere 
de  la  Belgique.  Ann.  Mus.  d'Hist.  Nat.  Belg.,  1882-85,  vol.  vi. — LindstrUvi,  G.,  On  the  Silurian 
Gastropoda  and  Pteropoda  of  Gotland.  K.  Svensk.  Vetensk.  Akad.  Handl.,  1884,  vol.  xix. 
— Ferner,  J.,  Gasteropodes,  in  Barrande's  Systeme  silurien  du  centre  de  la  Boheme,  vol.  iv. 
Prague,  1903-7. — Salter,  J.  W.,  Catalogue  of  the  collection  of  Cambrian  and  Silurian  fossils  in 
the  Museum  of  Cambridge,  1873. — Spitz,  Ä.,  Die  Gastropoden  des  karnischen  Unterdevon.  Beiträge 
Pal.  und  Geol.  Österr.-Ung.,  etc.,  1907,  vol.  xx. — Ulrich,  E.  0.,  and  Scoßeld,  W.,  The  Lower 
Silurian  Gastropods  of  Minnesota.     Rept.  Geol.  and  Nat.  Hist.  Surv.  Minn.,  1897,  vol.  iii.,  pt.  2. 

B.  On  Mesozoic  Forms. — Ahlburg,  J.,  Die  Trias  im  s.  Oberschlesien.  Abhandl.  Preuss.  Geol. 
Landesanst.  u.  Bergakad.,  1906,  n.s.,  Heft  50. — Böhm,  J.,  Die  Gastropoden  des  Marmolatakalkes. 
Paläontogr.,  1895,  vol.  xlii. — BrUsamlen,  R.,  Beitrag  zur  Kenntnis  der  Gastropoden  des  schwäbischen 
Jura.  Paläontogr.,  1909,  vol.  Ivi. — Deninger,  K.,  Die  Gastropoden  der  sächsischen  Kreideformation. 
Beiträge  Pal.  und  Geol.  Österr.-Ung.,  etc.,  1905,  vol.  xviii. — Haberle,  D.,  Paläontologische  Unter- 
suchungen triadischer  Gastropoden  aus  dem  Gebiet  von  Predazzo.  Verhandl.  Naturh.  Med.  Vereins. 
Heidelberg,  1908,  n.s.,  vol.  ix. — Hudleston,  W.  H.,  A  Monograph  of  the  British  Jurassic  Gasteropoda. 
Paläontogr.  Soc,  1887-94. — Kaunhoven,  F.,  Die  Gastropoden  der  Mästricher  Kreide.  Paläont. 
Abhandl.,  1897,  n.s.,  vol.  iv.  (viii.). — Koken,  E.,  Die  Gastropoden  der  Trias  um  Hallstadt.  Jahrb. 
Geol.  Reichs- Anst.  Wien,  1897,  vol.  xlvi.,  and  Abhandl.,  vol.  xvii. — Morris,  J.,  and  Lycett,  J., 
Mollusca  from  the  Great  Oolite  :  Univalves.  Palaeontogr.  Soc,  1850. — d'Orhlgny,  A.,  Paleontologie 
fran9aise.  Terrains  jurassiques  ii.  et  iii.,  1850-82.  Terrains  cretaces  ii.,  1842-3. — IHcard,  E., 
Beitrag  zur  Kenntnis  der  Glossophoren  der  mitteldeutschen  Trias.  Jahrb.  Preuss.  Landesanst., 
1901,  vol.  XXV. — Stoliczka,  F.,  Cretaceous  Fauna  of  Southern  India.  Gastropoda,  vol.  ii.  Mem. 
Geol.  Surv.  East  India,  1868. — Zittel,  K.  A.,  Die  Gastropoden  der  Stramberger  Schichten.  Mitt. 
Mus.  Bayer.  Staates,  1873,  vol.  ii.,  pt.  iii. 

C.  On  Tertiary  Forms. — Beyrich,  E.,  Die  Conchylien  des  norddeutschen  Tertiärgebirges. 
Zeitschr.  Deutsch.  Geol.  Ges.,  1853-6,  vols.  v.,  vi.,  viii. — Gossmann,  M.,  Mollusques  eoceniques 
de  la  Loire-Inferieure,  i.  and  ii.  Bull.  Soc.  Sei.  Nat.  Ouest  Nantes,  vols.  vii.-ix.,  1895-1901. 
Contribution  ä  la  paleontologie  fran9aise  des  terrains  jurassiques.  Mem.  Soc.  Gool.  France,  1895, 
1898,  Mem.  Nos.  14  and  19.  Essais  de  paleontologie  comparee,  i.-iv.  Paris,  1895-1904. — Gossmann, 
M.,  and  Pissarro,  G.,  Faune  eocenique  du  Cotentin.  Bull.  Soc.  Geol.  Normandie,  1900-2,  vols.  xix.- 
xxi. — Dali,  W.  H.,  Contributions  to  the  Tertiary  Fauna  of  Florida.  Trans.  Wagner  Free  Inst.  Sei., 
1895-97,  vols.  iii.,  v. — Harris,  G.  F.,  The  Australasian  Tertiary  Mollusca.  Cat.  Tert.  Mollusca 
Brit.  Mus.,  pt.  i.,  1897. — Hoernes,  R.,  and  Auinger,  M.,  Die  Gastropoden  der  Meeresablagerungen 
der  ersten  und  zweiten  Mediterranstufe.  Vienna,  1879-91. — Martin,  K.,  Die  Fossilien  von  Java. 
Samml.  Geol.  Reichsmus.  Leiden,  1895-99,  n.s.,  vol.  i.,  pts.  2-10. — Newton,  R.  B.,  Systematic  List 
of  British  Oligocene  and  Eocene  Mollusca,  1891. — Philippi,  R.  A.,  Die  tertiären  und  quartiären 
Versteinerungen  Chiles.  LeipsiQ,  1887.  —  Sandberger,  F.,  Land-  und  Süsswasserconchylien  der 
Vorwelt.  Wiesbaden,  1870. —  Vinassa  de  Regny,  P.  E.,  Synopsis  dei  molluschi  terziari  delle  Alpe 
venete.  Palaeontogr.  Italica,  1896-97,  vols.  i.,  ii.  —  Wood,  E.,  The  Phylogeny  of  certain  Cerithiidae. 
Ann.  N.Y.  Acad,  Sei.,  1910,  vol.  xx. — Grabau,  A.  W.,  Studies  of  Gastropoda.  Amer.  Nat., 
1902-3,  vols.  xxxvi.,  xxxvii.— Phylogeny  of  Fusus.     Smiths.  Mise.  Coli.,  1904. 


CLASs  IV      '  GASTKOPODA  ,  515 

of  considerable  size,  and  in  some  forms  (Strombidae)  the  animal  is  enabled  to 
spring  quite  a  distance  by  contracting  the  foot.  The  mantle  lobe  is  elevated 
along  the  back  like  a  hood,  extending  as  far  as  the  head,  and  usually  secretes 
a  shell  from  its  outer  surface.  The  shell  (which  may  be  wanting  or  obsoles- 
cent  in  the  adult)  Covers  the  intestinal  sac  and  lung-cavity,  and  usually  permits 
of  retraction  into  it  of  the  entire  body  of  the  animal.  Body  and  shell  are 
united  by  muscular  attachment ;  in  spiral  shells  the  muscle  is  fastened  to  the 
columella,  but  in  bowl-shaped  forms  to  the  inner  surface  of  the  shell. 

The  nervous  System  consists  of  two  cerebral  ganglia,  the  paired  pedal  and 
visceral  ganglia,  and  two  or  three  additional  pairs,  all  of  which  are  united  by 
commissures.  A  complete  crossing  of  the  commissures  of  the  visceral  ganglia 
sometimes  takes  place  (Chiastoneura),  but  in  other  forms  they  run  parallel 
(Orthoneura). 

The  peculiar  armature  of  the  mouth,  although  developed  in  all  classes  of 
Mollusks  except  Pelecypods,  is  especially  characteristic  of  Gastropods.  This 
consists  of  one  or  more  horny  plates  on  the  anterior  upper  margin  of  the 
Oesophagus,  opposed  to  which  is  a  chitinous  grating,  strap  or  radula,  resting 
upon  the  tongue  or  odontophore.  The  tongue  itself  is  merely  a  swelling  at 
the  bottom  of  the  buccal  cavity.  The  radula  is  usually  quite  long,  and  is 
beset  with  innumerable  small  teeth  or  hooks,  placed  in  transverse  and 
longitudinal  rows,  and  exceedingly  constant  in  form  throughout  the  several 
groups.  The  characters  of  the  radula  among  the  difFerent  groups  were 
therefore  advantageously  employed  by  Lov^n  and  Troschel  as  a  basis  of 
Classification. 

The  Oesophagus  conducts  into  a  long,  coiled,  intestinal  canal,  which  is 
surrounded  by  a  large  liver,  the  kidneys,  and  numerous  glands.  The  intestine 
ends  in  an  anal  opening  placed  anteriorly.  The  heart,  as  a  rule,  has  one 
auricle  (Montocardia),  more  rarely  two  (Diotocardia),  and  serves  as  a  central 
organ  for  the  supply  of  a  much  branched  System  of  blood-vessels.  When  the 
gills  or  lungs  are  placed  in  front  of  the  heart  (Prosobranchia,  Pulmonata),  the 
auricles  are  anterior  to  the  ventricle ;  but  when  placed  behind  the  heart 
(Opisthobranchia,  Fteropoda)  the  auricle  is  posterior. 

Only  a  few  Gastropods  breathe  through  the  general  surface  of  the  body, 
and  are  without  distinct  organs  of  respiration ;  the  vast  majority  possess  gills 
or  lungs.  The  gills  are  lamellar  or  tuft-like,  sometimes  branched  or  feathered 
lobes  of  the  integument,  and  are  usually  placed  in  the  gill-cavity  below  the 
mantle  ;  more  rarely  they  project  freely  on  the  back  or  at  the  sides.  Only 
exceptionally  are  they  present  in  large  numbers  and  symmetrically  developed  ; 
and  when  so  disposed  they  are  always  secondary  structures  not  homologous 
with  the  normal  ctenidia.  Typically  there  are  two  gills,  but  the  left  usually 
becomes  completely  atrophied,  and  the  right  takes  up  a  median  position,  con- 
sequent  upon  the  torsion  of  the  body,  or  even  migrates  over  to  the  left  side. 
Air-breathing  snails  have  the  gills  replaced  by  a  sac-like  cavity,  the  lung 
occupying  the  place  of  the  gill-cavity.  The  walls  of  this  respiratory  cavity 
are  covered  with  a  finely  branched  network  of  blood-vessels.  The  Arnpul- 
lariidae  and  Siphonariidae  possess  both  gills  and  lungs.  The  opening  of  the 
respiratory  cavity  ns  reduced  to  a  round  or  crescentic  aperture,  called  the 
breathing  pore.  The  sides  of  this  pore,  in  operculated  snails,  are  often  pro- 
duced  outwards,  so  as  to  form  a  closed  or  cleft  tube,  corresponding  with  which 
there  is  frequently  a  canal-like  process  of  the  shell. 


516  .  MOLLUSCA  '  phylum  vi 

Gastropods  are  remarkable  for  the  extreme  differentiation  of  their  repro- 
ductive  Organs.  The  sexes  are  distinct  in  the  Prosobranchia  and  Heteropoda, 
but  united  in  the  Opisthohranchiata,  Pteropoda  and  Pulmonata.  The  ovarian 
and  seminal  ducts  of  hermaphrodites  sometimes  open  into  a  common  cloaca, 
or  they  may  terminate  in  separate  openings. 

The  shell,  as  has  already  been  remarked,  is  secreted  by  the  mantle,  and  is 
limited  in  form  and  size  by  the  configuration  of  the  intestinal  sac.  It  is 
composed  of  a  chitinous  substance  {conchioUn)  infiltrated  with  lime  carbonate, 
or  exceptionally  with  sulphate  of  lime  in  small  quantities.  Shell  characters 
are  of  great  importance  in  distinguishing  genera  and  species,  but  their  value 
in  classifying  larger  groups  is  comparatively  slight,  owing  to  the  fact  that 
very  similar  shells  are  often  developed  among  forms  which  difFer  widely  in 
their  general  Organisation.  Two  forms  of  shell-habit  occur,  the  symmetrical 
and  the  spiral.  The  first  are  flat,  conical  or  saucer-shaped,  and  characterise 
only  a  few  groups  (Cyclobranchia,  Aspidohranchia,  Pulmonata).  Transition 
forms  between  the  symmetrical  and  spiral  are  to  be  observed  in  conical  shells 
with  slightly  inrolled  beaks.  Exceptional  forms  of  the  spiral  shell  are  seen 
in  Vermetus,  which  is  irregularly  coiled,  and  in  Planorhis,  Bellerophon  and 
Atlanta,  coiled  in  one  plane  (discoidal).  Usually  the  shell  forms  a  screw-like 
spiral,  and  rests  upon  the  back  of  the  creature  in  such  a  way  that  the  apex  is 
directed  upward  and  backward,  the  aperture  f orward  and  downward.  Holding 
the  shell  upright  so  that  the  apex  is  above,  and  the  aperture  below,  facing 
the  observer,  it  is  said  to  be  right-handed  or  dextral  when  the  opening  is  on 
the  right  side,  and  left-handed  or  sinistral  when  on  the  left  side.  By  far  the 
larger  number  of  Gastropods  are  dextral ;  but  a  few  (Clausilia,  Physa,  Spirialis) 
are  normally  sinistral.  Right-handed  individuals  of  normally  left-handed 
genera,  as  well  as  pathologic  sinistral  individuals  of  normally  right-handed 
forms,  are  occasionally  met  with. 

In  drawing  and  describing  Gastropod  shells,  the  apex  is  ordinarily  directed 
upward,  so  that  the  right-  or  left-handedness  may  be  seen  at  a  glance.  It  is 
also  customary  to  employ  the  terms  above  and  below  in  the  same  sense  as 
posterior  and  anterior.  The  height  or  length  of  the  shell  is  measured  by  a 
line  drawn  from  the  apex  to  the  lower  margin  of  the  aperture. 

The  shell  is  to  be  considered  as  a  more  or  less  rapidly  wädening  cone, 
which  is  wound  either  around  an  axial  pillar,  called  the  columella,  or  about  a 
central  tubulär  cavity.  Each  coil  of  the  tube  is  termed  a  whorl,  and  all  the 
whorls  except  the  last  one  form  together  the  spire.  The  last  or  body  whorl 
is  often  very  much  larger  than  the  preceding ;  its  lower,  sometimes  flattened 
surface  is  called  the  hase.  As  a  rulö,  the  whorls  are  in  contact  with  each 
other,  each  in  succession  either  partly  or  entirely  covering  the  preceding ;  but 
in  rare  cases  they  form  a  loose  spiral,  in  which  the  whorls  are  separated  from 
one  another.  The  spire  is  said  to  be  convolute  when  the  later  whorls 
entirely  conceal  the  earlier  ones,  as  in  Cypraea.  The  line  between  two  con- 
tiguous  whorls  is  known  as  the  suture.  According  to  the  manner  of  inrolling, 
various  shell  contours  are  produced,  requiring  numerous  descriptive  names, 
such  as  conical,  auriform,  turbinate,  fusiform,  cylindrical,  spherical,  oval, 
pyramidal,  etc. 

When  the  inner  parts  of  the  whorls  coalesce  to  form  a  columella,  the  shell 
is  said  to  be  imperforate ;  it  is  perforate  when  they  do  not  so  coalesce,  but 
leave  a  central  tubulär  cavity  instead.     The  opening  of  this  Perforation  below, 


CLASS  IV 


GASTROPODA 


517 


Apex 


Siiture 


in  the  centre  of  the  base,  is  designated  the  umbilicus.  A  true  ümbilicus 
reaches  to  the  apex  of  the  shell ;  when  confined  to  the  last  whorl  only,  it  is 
called  a  false  umbilicus.  An  umbilical  fissure  is  sometimes  produced  through 
a  partial  covering  of  the  umbilicus  by  the  reflected  inner  lip,  er  by  a  shelly 
growth  termed  the  callus. 

The  aperture  is  variable  in  form,  being  most  commonly  oval,  rounded, 
crescentic  or  half-round,  but  is  sometimes  contracted  or  even  fissure-like.  Its 
margin  is  called  the  peristome,  the  outer  partof  which  forms  the  outer  lip,  and 
the  part  next  the  columella  the  inner  lip.  Some  shells  have  a  continuous, 
uninterrupted  peristome,  but  as  a  rule  the  inner  and  outer  lips  are  discon- 
nected.  The  aperture  is  said  to  be  entire  when 
rounded  anteriorly  (inferiorly),  as  in  the  Holosto- 
mata  \  it  is  channelled  when  a  basal  notch  or 
canal,  caused  by  an  inbending  of  the  margin 
next  the  base  of  the  columella,  is  developed. 
This  anterior  canal  serves  for  the  lodgment  of 
the  siphon,  as  the  tube  is  called  which  conducts 
water  to  the  gills ;  it  may  be  either  straight  or 
recurved,  and  in  the  Siphonostomata  it  is  greatly 
produced,  sometimes  even  exceeding  the  aper- 
ture in  length.  The  outer  lip  may  be  entire  or 
incised,  thin  and  sharp  or  thickened,  curved 
outward  (reflected)  or  inward  (inflected),  even 
or  crenulated,  or  it  may  be  produced  into  alar 
or  finger-like  processes.  It  is  sometimes  chan- 
nelled by  a  canal  at  the  posterior  border,  in 
which  the  anal  or  excurrent  canal  is  placed. 
The  Upper  or  posterior  portion  of  the  inner 
margin  is  commonly  designated  as  the  parietal 
wall,  in  contradistinction  from  the  lower  or 
columellar  portion.  The  inner  lip  is  formed 
either  by  the  wall  of  the  penultimate  whorl,  or 
by  a  calcareous  callus ;  like  the  outer  lip  and 
columella,  it  may  bear  spiral  folds,  which  in 
some  cases  extend  backward  as  far  as  the 
apex  (Fig.  843),  but  sometimes  are  progres- 
sively  absorbed  internally. 

The  external  ornamentation  usually  consists  of  impressed  lines  or  grooves, 
or  of  elevated  ridges,  ribs,  folds,  nodes,  spines  and  the  like.  The  markings 
are  called  spiral  when  they  run  parallel  with  the  suture,  and  axial  or 
longitudinal  when  they  meet  the  suture  at  right  angles  or  obliquely.  Many 
Gastropods  are  brilliantly  coloured ;  some  have  a  smooth  or  rough,  and  others 
a  velvety  or  hairy  epidermis.  The  fossilisation  process  is  usually  destructive 
not  only  of  the  epidermis,  but  of  the  coloration  as  well. 

The  essential  constituent  of  univalve  shells  is  aragonite,  which  usually 
forms  a  homogeneous,  porcelain-like  layer.  Many  families  have  in  addition 
to  this  an  inner  nacreous  layer,  which  is  made  up  of  alternating  strata  of 
conchiolin  and  calcium  carbonate,  running  parallel  with  the  inner  surface  of 
the  shell.  The  porcellanous  material  is  composed  of  three  distinct  layers, 
each  of  which  is  made  up  of  thin  laminae,  and  the  laminae  in  turn  of  very 


Canal 


Fio.  843. 


Mitra  episcojmlis  Linn.  View  of  shell 
sawed  through  longitudinally,  showing 
columella  with  folds. 


518  MOLLUSCA  phylüm  vi 

small  oblique  prisms.     The  laminae  of  the  middle  layer  are  disposed  at  right 
angles  to  those  of  the  adjacent  layers. 

Many  Gastropods  have  a  calcareous  or  horny  plate,  called  the  oj)erculum, 
attached  to  the  posterior  part  of  the  foot,  and  serving  to  close  the  aperture 
more  or  less  completely  when  the  animal  withdraws  into  its  shell.  Being 
most  commonly  of  corneous  nature,  it  is  seldom  preserved  fossil ;  sometimes, 
however,  it  is  calcareous,  and  may  attain  considerable  size  and  thickness.  On 
the  outer  surface  it  may  be  smooth,  furrowed,  granulated  or  covered  with 
excrescences.  The  nucleus  or  initial  point  of  growth  is  sometimes  central,  or 
may  be  eccentric  or  even  marginal  in  position ;  it  may  be  surrounded  by  con- 
centric  markings,  or  form  the  origin  of  a  spiral  consisting  of  few  (paucispiral) 
or  many  (multispiral)  whorls.  Certain  Solariidae  have  a  conical  operculum, 
which  is  covered  externally  with  numerous  spiral  lamellae. 

The  embryonic  stages  of  Gastropods  are  usually  completed  in  the  egg- 
capsule.  Early  in  its  development  the  embryo  forms  a  small  shell,  the  proto- 
conchf  which  consists  sometimes  of  several  whorls,  and  not  infrequently  difFers 
in  form  from  the  shell  of  the  adult.  The  protoconch  remains  attached 
to  the  apex  for  a  time,  in  the  form  of  a  small  glistening  knob,  or  a  short 
smooth  spire,  which  occasionally  Stands  at  an  angle  to  the  rest  of  the  shell,  or 
is  even  twisted  in  a  contrary  direction  (heterostrophic).  Should  the  protoconch 
become  decollated,  a  small  calcareous  plate  closes  over  the  apex  of  the  spire. 

All  branchiate  Gastropods  are  aqueous  in  habitat,  but  there  are  some 
forms  having  a  lung-cavity  which  live  permanently  in  fresh  water  (Lymnaeidae), 
and  others  which  are  exclusively  marine  (Siphonariidae).  The  greater  number 
of  Gastropods,  especially  the  large  and  solid  forms,  frequent  the  coast-line, 
and  inhabit  comparatively  shallow  water.  Some  become  attached  to  rocks 
and  plants,  others  burrow  in  sand  or  mud.  A  great  reduction  in  the  Gastropod 
fauna  is  noticed  at  a  depth  of  between  70  and  100  metres,  but  many  genera 
(Pleurotoma,  Fusus,  Natica,  Odostomia,  Eulima,  Scissurella,  Turbo,  Cylichna, 
Tornaüna,  Adaeon,  etc.)  persist  into  the  greatest  depths  yet  explored.  Most 
marine  Gastropods  are  killed  by  removal  into  fresh  water ;  a  few  genera, 
however,  are  able  to  maintain  their  existence  in  brackish  or  in  fresh  water 
(Cerithium,  Littorina,  Rissoa,  Trochus,  Purpura,  etc.).  On  the  other  band,  many 
fresh-water  forms  (Melania,  Melanopsis,  Neritina,  AmpuUaria,  Lymnaea,  Planorhis) 
can  survive  in  brackish  or  even  strong  salt  water.  There  are  also  large 
numbers  of  terrestrial  Gastropods,  especially  in  tropical  regions. 

Most  Gastropods  are  herbivorous,  but  a  few  subsist  upon  living  or  decom- 
posed  animal  food.  Many  genera  (Natica,  Buccinum,  Murex)  perforate  the 
Shells  of  other  MoUusks  with  their  radula,  and  extract  the  contents. 

Classification. — Ordinal  divisions  have  been  based  since  the  time  of  Cuvier 
and  Milne  Edwards  upon  the  respiratory  organs,  and  the  structure  of  the  foot 
(whether  adapted  for  swimming  or  crawling).  The  reproductive  organs,  and 
the  structure  of  the  heart  and  nervous  System,  are  also  of  prime  importance. 
For  separating  smaller  groups,  shell  characters  and  the  radula  are  largely 
employed.  Gastropods  may  be  divided  into  two  subclasses :  Stre^itoneura, 
with  the  Orders  Ctenohranchiata  and  Aspidohranchia ;  and  Euthyneura,  with 
the  Orders  Opisthohranchia  and  Pulmonata. 


CLASS  IV  GASTROPODA  519 

Subclass  1.     STREPTONEURA  Spengel. 

{Prosohranchia  Cuvier;  Cochlides  von  Ihering.) 

Gastropods  in  which  the  visceral  commissures  are  crossed,  producing  an  S-shaped 
loop ;  sesces  separate  ;  heart  behind  the  gilt ;  a  shell  almost  always  developed,  and 
with  few  exceptions  provided  with  an  operculum. 

The  Streptoneura,  or  Prosobranchiates  as  they  are  often  called,  constitute  by 
far  the  largest  group  of  Gastropods,  and  comprise  at  least  20,000  living  and 
fossil  species.  The  shell  is  usually  spiral,  more  rarely  symmetrical,  saucer- 
shaped  or  conical.  The  intestinal  sac  is  twisted  from  left  to  right,  so  that 
the  anal  opening  is  placed  on  the  right  side  near  the  head,  and  the  organs 
normally  belonging  to  the  right  side  (kidneys  and  gills)  migrate  over  to  the 
left.  As  a  rule,  one  only  (the  right)  of  the  lamellar  gills  is  fully  developed, 
but  in  some  cases  the  two  are  of  equal  size.  The  gill  veins  enter  anteriorly 
into  the  single  or  double-auricled  heart. 

The  large  number  of  Prosobranchiates  have  been  variously  classified. 
Cuvier,  Milne  Edwards,  and  most  of  the  older  zoologists  laid  emphasis  upon 
the  number  and  formation  of  the  gills ;  Troschel  and  Loven  upon  the  char- 
acters  of  the  radula ;  von  Ihering  upon  the  nervous  system  ;  Mörch  and  more 
recently  Perrier  and  Bouvier  upon  the  structure  of  the  heart.  As  none  of 
these  characters  leave  a  marked  impress  upon  the  shell,  they  are  without 
practical  value  in  Paleontology.  Nevertheless,  the  two  Orders  Aspidobranchia 
and  Ctenobranchia  form  natural  groups,  and  are  recognised,  albeit  under 
difFerent  names,  in  all  classificatory  Systems. 

Order  1.     ASPIDOBRANCHIA  Schweigger. 

{Gyclohranchia  and  Scutihranchia  Cuvier.) 

Nervous  system  not  much  concentrated  anteriorly  ;  a  penis  generally  ahsent ;  radula 
multiserial. 

This  group  includes  most  Paleozoic  Gastropods,  and  is  regarded  as  the  most 
primitive  expression  of  the  class.  The  nervous  system  and  radula  are  of  low,  decidedly 
generalised  type,  and  in  some  families  two  symmetrical  ctenidia  or  gills  are  developed, 
as  in  Pelecypods. 

Suborder  A.     DOCOGLOSSA  Troschel.     Limpets. 
{Gyclohranchia  pars  Cuvier  ;  Heterocardia  Perrier.) 

Symmetricalj  with  conic  or  howl-shaped  non-spiral  shells,  or  with  spiral  shells  coiled 
in  the  same  plane ;  operculum  wanting.  Organs  of  respiration  rqnesented  either  hy  a 
ring  of  laminae  {secondary  or  pallial  gills)  heneath  the  mantle  margin,  or  by  a  comh- 
shaped  true  gill  in  front^  anterior  to  the  heart,  or  by  hoth  true  and  secondary  gills. 
Tongue  set  with  peculiar  modified  teeth.  Heart  with  one  auricle.  Marine.  Cambrian 
to  Recent. 

The  impression  of  the  adductor  muscle  in  the  shell  cavity  is  horseslioe-shaped, 
open  in  front.  In  the  family  Tryblidiidae,  the  horse-shoe  is  broken  into  numerous 
separate  impressions.  The  three  families  Patellidae,  Acmaeidae  and  Lepetidae  have 
the  impression  uninterrupted,  and  are  distinguished  by  the  structure  of  the  gills.    The 


520  MOLLUSCA  phtlüm  vi 

Shells  themselves  exhibit  little  Variation  in  form,  and  hence  tlieir  generic  and  even 
family  affinities  are  almost  always  doubtful  in  tlie  fossil  state.  About  400  Eecent 
species  of  limpets  are  known  ;  these  are  almost  exclusively  shallow  water  inhabitants, 
and  subsist  on  algae.     Fossil  forms  are  uncommon. 

In  tlris  very  primitive  groiip  two  divisions  have  been  proposed  by  Ulrich  and 
Scofield  :  (1)  the  Patellacea,  which  embraces  the  first  tliree  families  noted  below ;  and 
(2)  the  Bellerophontacea,  including  the  remaining  five  families.  The  latter  group  by 
Meek  was  regarded  as  involute  Fissureil idae,  a  view  which  is  not  withoiit  plausibility. 

Family  1.     Patellidae  Carpenter. 

Patella  Linn.  Cup-shaped,  round  or  oval,  depressed  conical,  with  sub-central  or 
eccentric  apex.     Surface  usually  with  radiating  ribs  or  Striae.     Silurian  to  Eecent. 

Helcion  Montf.  Differs  in  having  the  beak  strongly  recurved  anteriorly.  Eocene 
to  Eecent. 

Helcioniscus  Dali ;  Nacella  Schum.     Eecent. 

Family  2.     Acmaeidae  Dali. 

Acmaea  Eschscholtz  {Tectura  auct.)  (Fig.  844,  B).  Like  Patella,  but  shell  having 
generally  a  differentiated  marginal  band  inside ;  externally  smooth,  finely  Stria ted,  or 
radially  ribbed.  Beak  anterior  to  the  middle.  Silurian  to  Eecent.  Lottia  Gray  is 
closely  allied. 

Scuiria  Gray  (Fig.  844,  G).  High  conical,  smooth,  with  sub-central  beak.  Jura 
to  Eecent. 

A  B  C  D 


844. 


A,  Archinacella  cingulata  Vir.  Ordovician  ;  Kentucky.  B,  Acmaea  raincourti  Deah.  Eocene;  Auvers,  near 
Paris.  C,  Scurria  nitida  Deslongcli.  Upper  Jura ;  Langrune,  Calvados,  l/i.  D,  Helcionopsis  striata  Ulr. 
Ordovician  ;  Kentucky. 

Metoptoma  Phil.  Depressed  conical  with  sub-central  beak.  Posterior  side  exca- 
vated.     Silurian  to  Carboniferous. 

Lepetopsis  Whitf.     Silurian  to  Carboniferous. 

The  genera,  Palaeacmaea  Hall;  Archinacella  Ulrich  and  Scofield  (Fig.  844,^);  and 
Scenella  Billings  are  the  oldest  representatives  of  the  Docoglossa.  They  are  small, 
smooth  or  radially  ornamented,  and  scarcely  to  be  distinguished  from  Acmaea. 
Lepeta  Gray  and  Lepetella  Verrill  are  small  simple  limpets  of  the  Eecent  and  late 
Tertiary,  with  degenerate,  aborted  gills.     They  form  the  family  Lepetidae.  * 

Helcionopsis  Ulr.  and  Scof.  (Fig.  844,  i>),  and  Gonchopeltis  Walcott,  from  the 
Ordovician  of  North  America,  are  doubtfully  referred  to  this  vicinity. 

Family  3.     Tryblidiidae   Pilsbry. 
Limpets  with  the  muscle  scar  broken  into  numerous  separate  impressions.     Silurian. 


CLASS  IV 


GASTROPODA 


Tryhlidium  Lindströni  (Fig.  845).  Shell  depressed,  very  thick,  oval,  with  anterior 
beak  ;  ornamented  externally  with  eoiicentric  lamellae.  Six  pairs  of  miiscle  scars 
arranged  in  tlie  form  of  a  horse-shoe.     Ordovician  anid  Silurian. 


Family  4.     Cyrtolitidae  Ulrich  and 
Scofield. 

Symmetrical,  involute  shells  with  two  or 
three  volutions,  barely  in  contact,  sharply 
angular  dorsally ;  aperture  not  expanded,  the 
sinus  V-shaped,  never  deep,  sometimes  want- 
ing ;  slit  absent ;  surface  reticulate.  Ordo- 
vician and  Silurian. 

Cyrtolites  Conrad  (Fig.  846,  Ä,  B).  Shell 
carinated  on  the  back  and  often  on .  the 
sides,  giving  a  sub-quadrate  cross  section  ;  no 
slit  band. 

Gyrtolitina  Ulrich.  Small  thin  shells 
with  a  slit  band. 

Microceras  Hall. 


Fig.  845. 

Tryhlidiuvi  reticulatum  Lindström.  Silurian ; 
Gotland.  A,  Internal,  and  B,  external  aspect 
(after  Lindström). 


Fig.  846. 

A,  B,  Cyrtolites  oniatus  Conrad.     Ordovician  of  Boonville,  New  York,  and  Cincinnati,  Ohio.     C-E,  Sinuites 
cancellatus  (Hall).    Ordovician  of  Minnesota. 

Family  5.     Sinuitidae,  novum.     {Protowarthiidae  Ulr.  and  Scof.). 

Symmetrical,  involute  shells  with  aperture  not  dhrwptly  expanded;    outer  lip  and 
of  growth  with  a  broad  or  narrow  dorsal  sinus  ;  slit  and  band  wanting. 

Sinuites  Koken  {Protowarthia  U.  and  S.)  (Fig.  846,  G-E).     Aperture  large  with 
outer  lip  bilobate  ;  dorsum  convex  ;  umbilicus  closed.     Ordovician  to  Devonian. 
Bucanella  Meek.     Dorsum  of  shell  trilobate  ;  umbilicus  large.     Silurian. 
Owenella  Ulr.  and  Scof.      Cambrian. 


Family  6.     Bucaniidae  Ulrich  and  Scofield. 

Symmetrical,  involute  shells  with  rather  numerous  whorls  merely  in  contact  or 
embracing  slightly,  all  visible  in  the  umbilicus  ;  aperture  often  expanded  abriiptly  ;  dorsal 
slit  band  distinct  with  the  slit  long  and  narrow;  surface  with  transverse  lamellae  or 
lines  usually  crossed  by  short  ribs.     Ordovician  to  Devonian. 

Bucania  Hall  (Fig.  847,  A,  B).  Shell  of  three  to  five  depressed  volutions  coiled 
in  a  plane,  generally  with  a  wide  umbilicus  and  with  aperture  never  abruptly 
expanded.     Ordovician  and  Silurian. 

Salpingostoma  Eoemer  (Fig.  847,  G).  Aperture  abruptly  expanded,  trumpet-like  ; 
outer  half  of  last  whorl  with  a  long,  narrow  slit  closed  some  distance  behind  the 
apertural  expansion.      Ordovician  and  Silurian. 

Trematonotus  Hall.  Like  Salpingostoma  except  that  the  slit  band  is  replaced  by 
a  row  of  perforations.     Silurian  and  Devonian. 


522 


MOLLUSCA 


PHYLUM  VI 


Gonradella  U.  and  S.  (PhragmoUtes  Conrad)   (Fig.   847,  D,  E).     Ordovician  and 
Silurian. 

A  1!  C 


Fig.  847. 

A,  B,  Bucania  haüi  Ulr.  and  Scof.     Ordovician  ;  Minnesota.     C.  Salpingostoma  hudli  (Whitf.).     Ordovician  ; 
Illinois.     D,  E,  Conradella  fimbriata  Ulr.  and  Scof.     Ordovician  ;  Minnesota. 

Tetranota  U.  and  S.  Like  Bucania,  but  witli  four  dorsal  ridges.  Ordovician 
and  Silurian. 

Kohenia  U.  and  S.  Ordovician.  Megalomphala  Ulr. ;  Oxydiscus  Koken. 
Ordovician  to  Devonian. 


Family  7.     Bellerophontidae  M'Coy. 

Symmeti'ical,  involute  shells  with  rapidly  enlarging  wJiorls,  mouth  expanded 
laterally  and  ventrally  hut  not  dorsally  ;  umhüicus  small  or  closed  ;  inner  lip  thickened, 
outer  ivith  a  short  slit ;  slit  band  always  present ;  surface  with  lines  of  growth  only  or 
cancellated.     Cambrian  to  Triassic. 

The  Bellerophontidae  were  classed  by  Montfort  with  the  Cephalopoda  ;  by  Deshayes, 
on  accoimt  of  their  resemblance  to  Atlanta,  with  the  Heteropoda  ;  and  by  de  Koninck 

with  the  Aspidobranchiates.  The 
thick  Shells  sometimes  retain  traces 
of  their  original  pigmentation.  At 
least  300  Paleozoic  species  have 
been  described.' 

Bellerophon  Montfort  (Fig.  848). 
Distinguished  by :  (1),  the  absence 
of  sculpture  save  the  lines  of 
growth ;  (2)  the  small  or  entirely 
closed  umbilicus ;  (3)  the  moderate 
expanse  of  the  aperture ;  (4)  the 
callosity  on  the  inner  lip,  and  (5) 
a  well  developed  slit  band  terminat- 
ing  in  a  slit  in  the  outer  lip.     Or- 


Fio.  848. 

BelleropJion  bicarenus  Leveille.     Lower  Carboniferous  ; 
Tournay,  Belgium. 

dovician  to  Permian,  maximum  in  Carboniferous, 


Patellostium  Waagen.     Like  Bellerophon,  but  aperture  greatly  expanded.     Devonian 
and  Carboniferous. 


3LASS  IV 


GASTROPODA 


23 


Euphemus  M'Coy  (Fig.  849).     Differs  from  Bellerophon  in  tlie  revolving  folds  of 
the  inner  lip.      Carboniferous. 

Bucanopsis  Ulricli.      Ordovician  to  Permian. 

Warthia,  Mogulia,  and  Stachella  Waagen.     Carboniferons. 


Fig.  849. 

Euphemus  nrii  Fleming.    Lower 
Carboniferous ;  EdinburKh. 


Fig.  850. 

Carinarojms  cymhula  Hall. 
Ordovician ;  Kentucky. 


Family  8.     Carinaropsidae  Ulrich  and  Scofield. 

Symmetrical,  almost  patelliform  shells  of  not  more  than  two  volutions  with  greatly 
expanded  aperture  within  which  is  a  hroad  concave  septum. 

Garinaropsis  Hall  (Phragmostoma  Hall,  non  Waagen)  (Fig.  850).    Dorsum  carinate  ; 
slit  band  occasionally  distingiüshable.     Ordovician  and  Silurian. 


Suborder  B.     RHIPIDOGLOSSA  Troschel. 

{Scutihranchiata  Ciivier ;  Zygohranchia  and  Diotocardia  von  Ihering.) 

Symmetrical  and  limpet-like  or  with  spiral  shells.  GUIs  pliime-Uke,  two  and  sym- 
metricalf  or  single.  Radula  with  several  large  plates  or  teeth  in  the  median  portion,  and 
excessively  numerouSj  crowded,  narrow,  hooh-shaped  teeth.      Operculum  often  present. 

The  Rhipidoglossa  comprise  both  air-breathing  and  aquatic  forms,  and  are  divisible 
into  two  series  :  Zygohranchia,  in  which  two  gills  are  developed,  and  the  shell  is 
generally  perforated  at  the  apex  or  has  a  slit  in  the  outer  lip ;  and  Anisohranchia, 
with  a  Single  gill  and  generally  unslit  shell. 


Family  1.     Haliotidae  Fleming. 

Shell  flattened,  auriform,  with  wide  aperture,  and  no  operculum.     Interior  nacreous, 
with  a  row  of  perforations  on  the  left  outer  margin.     Marine.     Cretaceous  to  Recent. 

Haliotis  Linn.     This,  the  solitary  genus,  occurs  very  rarely  fossil  except  in  the 
Quaternary. 

Family  2.     Pleurotomariidae  d'Orbigny. 

Shell  spiral,  sub-spherical,  turhinate,  conic,  turreted  or  Planorhoid,  nacreous  inter- 

li 


Fio.  851. 
/  "-  {Raphistomdia)  nulians  Wissm.    Keuper ;  St.  Cassian,  Tyrol.     B,  Pleurotomaria 
(Cryptaenia)  imlita  Goklf.     Lower  Lias  ;  Göppingen,  Würteniberg. 


524 


MOLLUSCA 


PHYLÜM  VI 


nally.  OiUer  lip  ivith  a  sUt,  from  which  a  slit-hand  {the  anal  fasciole)  extends  hackward, 
traversing  all  the  whorls.  The  slit  sometimes  replaced  by  one  or  more  perforations. 
Operculum  horny.     Cambrian  to  Kecent. 

Pleurotomaria  Sowb.  (Figs.  851-853).  Shell  broadly  conical  or  turbinate  ;  spire 
sometimes  high,  in  other  cases  depressed  ;  umbilicus  present  or  absent.  Guter  lip 
with  slit ;  growth-lines  strongly  recurved,  meeting  ■  in  the  slit-band.  Silurian  to 
Recent.  Foiir  living  and  several  hundred  fossil  species  known.  Rare  in  the  late 
Tertiary. 

Subgenera :     Ptychomphalus    Agassiz  ;     Mourlonia,    Worthenia,    Agnesia    de    Koninck ; 
Gosseletina,  Ivania  {Baylea  de  Kon.)  Bayle  ;  Raphistoinella  (Fig.  851,  A),  Zygites,  Laubella, 


Fig.  852. 

A,  PZetwoiomaria  iyifor^uato  Deslongchanips.     Middle  Lias  ;  May,  Calvados.     B,  P.  suhscalaris 
Deslongchamps.     Lower  Oolite  ;  Bayeux,  Calvados.     1/2- 


Fig.  853. 
Pleurotomaria  {Leptoinaria)  mojcrompTialla  Zittel. 


Tithonian ;  Stramberg,  Moravia. 


Stuorella,  ScMzodiscus  Kittl  ;  Brüonella  Kayser  ;   Hesperiella  Holzapfel ;  Cryptaenia  (Fig. 
851,  B),  Leptomaria  Deslongchamps  (Fig.  853),  etc. 

Porcellia  Leveille  (Leveüleia  Newton)  (Fig.  854).  Shell 
discoidal,  flat,  widely  iimbilicate,  nearly  symmetrical,  and 
all  but  the  first  few  whorls  coiled  in  the  same  plane.  Outer 
lip  Sharp,  with  long  slit.  Slit-band  prominent,  traversing 
the  central  portion  of  the  whorls.  Devonian  and  Carboni- 
ferous. 

Kohenella  Kittl.      Very  flat,  discoidal,  and  only  slightly 
asymmetrical,  with  a   broad  slit-band.      Trias.      K, 
(Hoernes). 


Fig.  854. 


Car- 


Porcellia  puzosi  Leveille.    ^ 

boniferous ;  Tournay,  Belgium 


CLASS  IV 


GASTROPODA 


525 


Pohjtremaria  de  Kon.     Shell  turbinate,  with  band  replaced  l)y  a  row  of  perfora- 
tions,  of  which  the  posterior  ones  are  siiccessively  closed.     Carboniferoiis. 

Düremaria  d'Orb.  (Fig.  855).     Two   oval  pefforations   connected    by   a  slit  are 
present  beliind  the  outer  lip  ;  base  with  an  umbilical  callus.     Jura. 

Trochotoma  Deslongch.    Shell  turbin-  a  b  c 

ate,  with  conical  base.  A  slit  closed  at 
either  end  is  present  behind  the  outer 
lip,  and  corresponding  to  it  is  a  slit-band. 
Trias  and  Jura. 


Fig.  855. 

Ditremaria  granulifera  Zittel.    Upper  Tithonian 
Stramberg,  Moravia. 


Fig.  856. 

A,  MurcMsonia  Mlincata  d'Arch.  and  Vern. 
Devonian ;  Paflfrath,  near  Cologne.  B,  M.  hlumi 
Klipstein.  Trias ;  St.  Cassian,  Tyrol.  C,  M. 
siibsulcata  de  Kon.  Lower  Carboniferous ;  Tour- 
nay,  Belgium.     Last  two  whorls,  2/j. 


Schizogonium  Koken  ;  l'emnotropis  Laube  ;  Gantantostoma  Sandb.     Devonian. 

MurcMsonia  d'Arch  and  Vern.  (Fig.  856).  Shell  turreted,  with  numerous  smooth 
or  ornamented  whorls  Outer  lip  with  a  slit,  and  corresponding  to  it  a  slit-band. 
Cambrian  to  Trias.     Maximum  distribution  in  Devonian  and  Carboniferous. 

Lophospira  Whitf.  (Fig.  857,  Ä,  ß).  Shell  with  more  or  less  elevated  spire  ; 
whorls  angular  on  the  periphery  and  bearing  from  one  to  five  distinct  carinae. 
Ordovician  to  Devonian. 

Hormotoma  Salter  (Fig.  857,  D).  Elongate,  beaded,  practically  imperforate  ;  outer 
lip  with  broad,  deep  notch.     Ordovician  and  Silurian. 

Liospira  Ulr.  and  Scof.  Shell  lenticular  with  aperture  deeply  notched  and 
band  scarcely  distinguishable.     Ordovician  and  Silurian. 

Schizolopha  and  Turritoma  Ulrich.     Oidovician  and  Silurian.     Seelya,' Plethospira 

A  B  CD 


Fi(i.  857. 

A,  B,  Lopliospira  sumnereiisis  (Safford).     Ordovician  ;  Tennessee.     C,  Trepospira  spheriüata  (Conrad).     Goal 
Measures  ;  Illinois.     D,  Hormotoma  salteri  Ulrich.     Ordovician  ;  Kentucky. 

and  Euconia  Ulrich.  Ordovician.  Goelocaulus  (Ehlert  ;•  Clathrospira  Ulr.  and  Scof. ; 
Ectomaria  Koken  {Solenospira  Ulr.  and  Scof.).  Ordovician  and  Silurian.  Bemhexia 
(Ehlert ;  Trepospira  Ulr.  and  Scof.  (Fig.  857,  G).     Devonian  and  Carboniferous. 


Family  3.     Fissurellidae  Risso. 

Shell  symmetricaly  cap-  or  limpet-shaped,  non-nacreous^  without  operculum.  Apex 
erect  or  pointing  hackward,  often  recurved,  perforated.  Anterior  margin  often  with  a 
fissure  ;  yoimg  shell  with  a  spiral  protoconch.  Marine  ;  shore  forms.  Carboniferous  to 
Recent. 


526 


MOLLUSCA 


PHYLUM  VI 


Of  tlie  three  subfamilies  iiito  wliicli  tliis  group  is  divided,  the  Fissurellinae  are 
known   only  in  tlie  recent  fauna.     Fissurellidinae  occur   in   the  Pliocene ;    all  tlie 
eai'lier  forms  are  Emarginulinae. 

Fissurella  Brug.  Sliell  conical,  oval,  witli  an  oval  apical  orifice 
bounded  inside  by  an  entire  calliis.  Recent.  The  niimerous  fossil 
species  referred  to  this  genus  belong  to  Fissuridea. 

Fissurellidea  d'Orb.  ;  Pupillaea  Gray  ;  Megatehennus  and  Luca- 
pinella  Pilsbry  ;  Macroschisma  Swains.  These  are  all  Recent  genera, 
witli  the  apical  orifice  very  large. 

Lucapina  Gray.  Like  Fissurella,  but  with  large  apical  orifice 
and  finely  crenate  periphery.     Pliocene  and  Recent. 

Fissuridea   Swains.  {Glyphis   Carp. ;  Fissurella  auct.)  (Fig.  858). 
Sliell    conical,  oval,  with    apex  in    advance    of   the  middle,  giving 
place  to  a  Perforation  which    is    bounded  inside    by  a   posteriorly 
truncate  callus.     Carboniferous  (?)  to  Recent ;  very  abundant  in  the  Tertiary. 

Puncturella  Lowe.     Shell  conical,  with  a  perforation  at  or  in  front  of  the  post- 
niedian  apex,  behind  which  there  is  a  shelf  within  the  cavity.     Eocene  to  Recent. 
Emarginula  Lam.  (Figs,  859,  860).     Conical  or  cap-shaped,  with  persistent  post- 

c 

AB 


858. 


Fissuridea  italica 
Defr.  Miocene ; 

Grund,  Hnngary. 


Fig.  859. 

Emarginula  schlotheimi 
Bronn.  Oligocene;  Wein- 
heim, near  Alzey,  Baden. 


Emarginula  muensteri  Pictet. 
Kei;per ;  St.  Cassian,  Tyrol. 
A,  B,  Natural  size.     C,  Enlarged. 


Fig.  861. 

Tdmula  goldfnssi  (Roem). 
Coral-Rag ;  Holieneggelsen, 
Hanover.  A,  Natural  size. 
B,  Enlarged. 


median  apex,  and  a  slit  in  the  front  margin  of  the  shell.  Surface  cancellated. 
Carboniferous  to  Recent. 

Bimula  Defr.  (Fig.  861).  Like  the  last,  but  slit  replaced  by  a  closed  hole  on  the 
anterior  slope.     Lias  to  Recent. 

Suhemarginula  Blainv.  Like  Emarginula,  but  slit  sliort  or  wanting,  and  no  slit- 
band.     Eocene  to  Recent. 

Scutus  Montf.  {Parmophorus  Blainv.).  Shell  depressed,  oblong,  without  fissure, 
slit,  or  slit-band ;  muscle  Impression  near  the  edge.     Eocene  to  Recent. 

The  families  Phenacolepadidae,  with  the  single  genus  Phenacolepas  Pils.  (Scutellina 
Gray),  Cocculinidae  and  Addisoniidae  are  recent  groups  allied  to  the  Fissurellida e. 


Family  4.     Euomphalidae  de  Koninck. 

Shell  depressed  conical  to  discoidal,  spirally  coiled,  more  or  less  deeply  and  widely 
umUlicate.  Whorls  sometimes  in  a  loose  spiral,  smooth  or  angular ;  the  earlier  whorls 
frequently  separated  of  hy  partitions.  Outer  lip  usually  with  a  shallow  indentation. 
Operculum  calcareous.     Cambrian  to  Cretaceous. 

The  Euomphalidae  belong  primarily  to  the  Paleozoic  era.  They  have  been 
variously  associated  with  the  Trochidae,  Turbinidae,  Littorinidae  and  Solariidae.'  The 
Shells  bear  a  strong  resemblance  to  those  of  the  last-named  group,  but  in  Solarium  the 
embryonic  apex  is  sinistral,  whereas  in  the  Euomphalidae  it  is  dextral.  Opercula  are 
known  with  certainty  in  only  a  few  genera,  such  as  Maclurea.  De  Koninck  surmised 
that  the  deeply  excavated,  slipper-shaped  opercula  from  the  Carboniferous,  described 
originally  as  Galceola  dumontiana,  are  referable  to  Euomphalus. 


CLASS  IV 


GASTROPODA 


527 


Btraiiarollina  Billings.      Canil)ri;ni.      OpUleta  Vanuxem.     Cambrian  to  Siluriaii. 
Maclurea  Lesciieur  ;  Maclurina  Ulr.  and  Scof.      Ordovician  and  Silurian. 

Platyschisma  M'Coy.  Thin  -  shelled,  (l.]ii<>s('d 
conical,  smootli.  Unibilicus  relatively  narruw ;  outer 
lip  witli  broad  sinus.  Silurian  to  Carboniferous.  P. 
helicoides  Sowb.     Carboniferous. 

Straparollus  Montf.  (Fig.  862).  Turbinate  to 
discoidal,  with  broad  unibilicus.  Whorls  smooth  or 
witli  fine  transverse  Striae.  Silurian  to  Jura  ;  especially 
abundant  in  Devonian  and  Carboniferous. 

Phanerotinus  Sowb.  Like  tlie  last,  except  tliat  tlie 
wliorls  form  an  open  spiral.      Carboniferous. 

Euomphalus  Sowb.  {Pleuronotus  Hall;  Schizostoma 
Bronn)  (Fig.  863).  Depressed  conical  to  discoidal,  witli  wide  umbilicus.  Spire 
flattened  or  eveii  concave  superiorly  ;  whorls  angular,  tlie  edges  sometimes  set  witli 
nodes  {Phymatifer  de  Kon.).  Outer  lip  with  emargination  at  the  upper  angle.  Silu- 
rian to  Trias  ;  maximum  in  Carboniferous. 

A  B 


Fig.  862. 

Straparollus  dionysii  Montf. 
Carboniferous ;  Vise,  Belgiuni. 


Euomphalus  catülus  (Sowb.).     Carboniferous  ;  Kildare,  Ireland. 
A,  Superior,  and  B,  Inferior  aspect. 


Fio.  864. 

DiscoJielix  orMs  Reuss.     Middle  Lias 
Hinter-Schafberg,  Austria. 


Subgenera :  Omphalocirrus  de  Ryckholt.  Devonian  and  Carboniferous.  Coelocentrus 
Zittel.     Trias. 

Discohelix  Dunk.  (Fig.  864).  Fiat,  discoidal ;  upper  side  flat  or  slightly  concave, 
the  lower  widely  umbilicate.  Whorls  rectangular,  with  sharp  edges.  Trias  to 
Oligocene. 

Eccyliomphalus  Portlock  ;  Eccyliopterus  Remele ;  Helicotoma  Salter.  Ordovician 
and  Silurian. 

Family  5.     Raphistomidae  Ulrich  and  Scofield. 

Gomprising  shells  intermediate  hetioeen  the  Euomphalidae  and  Pleurotomarudae^  and 
regarded  as  ancestral  to  these  f amilies  and  the  Trochidae. 

Eaphistoma  Hall.  Shell  depressed  or  completely  flattened  ;  whorls  angular  above  ; 
umbilicus  moderately  broad  ;  outer  lip  with  short  notch  on  the  keel.  Ordovician 
and  Silurian. 

Euomphalopterus  Roemer.  Distinguished  by  its  more  rounded  volutions  and 
excessively  developed  carinae.     Silurian. 

Scalites  Emmons,  non  Conrad.  Turbinate,  spire  only  moderately  high  and 
acuminate;  whorls  flattened  superiorly,  risiut^  sie]. like  one  above  the  otlier,  sharply 
angular  at  the  periphery,  produced  below.     Bods   w  liorl  very  large,  smooth;  aperture 


528 


MOLLUSCA 


PHYLUM  VI 


ßub-triangular,  faintly  notched  ;  no  umbilicus.      Ordoviciaii  (Chazy),  and  according  to 
Laube,  also  Triassic.     Type,  S.  angulatus  Emmons. 
Raphistomina  Ulr.  and  Scof.     Ordovician. 

Family  6.     Stomatiidae  Gray. 

Shell  depressed,  composed  of  a  few  very  rapidly  widening  whorls ;  nacreous  internally ; 
o,perture  large. 

Witli  tlie  exception  of  Stomatia  Helb.  and  Stomatella  Lamarck,  a  few  rare  repre- 
sentatives  of  wliicli  are  known  as  early  as  tlie  Cretaceous  (perliaps  also  Jurassic),  tliis 
family  belongs  to  tlie  Recent  period. 


Fig.  SC5. 

Omphalotrochus  discus  Sowb.     Silurian  ; 
Dudley,  England,     i/j  (after  Nicholson). 


866. 


Family  7.     Turbinidae  Adams. 

Shell  turhinate,  discoidal  or  turreted,  nacreous  internally.  Aperture  rounded  or 
oval;  inner  lip  smooth  or  with  callus,  the  outer  lip  never  reßecied.  Operculum  cal- 
careous,  very  thick,  convex  externally.      Ordovician  to  Recent. 

The   extremely  abiindant   Recent   Turbinidae    are  distinguished   principally  by 

cliaracters  of  tlie  operculum  ; 
but  inasmuch  as  tbis  is 
known  in  but  few  of  tlie 
fossil  forms,  tlie  precise  deter- 
mination  of  tlie  latter  is 
usually  uncertain.  It  is 
customary,  therefore,  to  group 
under  the  general  head  of 
Turbo  such  fossil  turbinate 
Shells  with  a  sub  -  circular 
Omphalotrochus  gioiosus   aperture  as  are  not  speciallv 

(Schloth.).    Silurian; Got-     ,.  ^.  •  i     n   i  , 

nd.      Operculum  pre-   aistinguished  by  some  otlier 

served    in    place    (after    pItj,  rnptpr« 

Lindströin).  cuaracters. 

Omphalotrochus  Meek 

(Polytropis  de  Kon. ; 
Oriostoma  Liiidström, 
non  Munier  -  Chalm.) 
(Figs.  865,  866).  Dis- 
coidal or  depressed 
conical,  widely  umbi- 
licate.  Whorls  round, 
ornamented  with 

raised       longitudinal 

keels.     Operculum  extremely  thick,  fiat  internally,  conical   externally,   multispiral. 

Ordovician  to  Carboniferous ;  especially  abundant  in  Silurian. 

Astralium  Link  (Figs.  867,  868).     Turbinate;  whorls  rough,  often  spinöse,  and 

usually  keeled.     Aperture  depressed,  witli  disconnected  margin.     Base  more  or  less 

flattened  ;   operculum  calcareous,  thick,  flat  internally,  spirally  coiled,  and  with  very 

eccentric  protoconch.     Trias  to  Recent. 

Subgenera:  Bolma  Risso  (Fig.  867);  Pachypoma,  Lithopoma,  Uvanilla  (Fig.  868),   Guil- 
fordia  Gray  ;  Calcar  Montfort,  etc. 

Turho  Linn.  (Fig.  869).  Turbinate  to  concial ;  aperture  nearly  circular.  Oper- 
culum calcareous,  thick,  flat  internally,  externally  convex,  multispiral,  with  sub-central 
nucleus.     Silurian  (?)  to  Recent. 


Fig.  867 


Astralium  (Bolma)  rugosum  Linn.     Pliocene  : 
Pienza,  Tuscany.     Shell  and  operculum. 


Astralium  (Uvanilla)  damon  Laube. 
Keuper ;  St.  Cassian,Tyrol. 


CLASS  IV 


GASTROPODA 


529 


Snhgenom -.Sarmaticus,   Ninella  (Fig.    869),   Modelia,   aud    Callopoma   Gray  ;  Henectus 
Humphr. ;  Batillus  ^c\\\\m.  ^  die.  "^ 

Gollonia  Gray  (Fig.  870).     Like  Turho,  but  operciilum  witli  a  thin  calcareous  layer 
disposed  in  a  spiral  rib.     Eoceiie  to  Recent. 


Family  8.     Phasianellidae  Trosc.liel. 

Shell  elongated,  oval,  thin,  smooth,  lustrous,  ijorcellanous,  not 
nacreous  internally, 

loithout  umhilicus.  Body 
lühorl  large,  with  oval 
aperture.  Opercuhim 

calcareous,  convex  exter- 
nally.  Devonian  to 
Recent. 

Phasianella  Lam. 
(Phasianns  Montf.)  (Fig. 
871).  With  the.jchar- 
acters  of  tlie  family. 
Cretaceous  to  Recent ; 
pcrhaps  also  Paleozoic. 


Fig.  869. 

Turho  (Ninella)  parlcitisoni 
Bast.  Oligocene  ;  Dax,  near 
Bordeaux. 


Fig.  870. 

Collonia- modcda 
Fuchs.  Oligocene ; 
Monte  Gninii,  near 
Castel  Goniberto, 
Italy. 


Fig.  871. 

Phasianella  gosauica 
Zekeli.  Turonian;Qosau, 
Austria. 


Family  9.     Delphinulidae  Fischer. 

Shell  turbinate  er  discoidal,  usually  thich,  nacreous  internally,  and  ornamented 
externally  ivith  spines,  rihs  or  folds.  Aperture  circular,  peristome  entire ;  outer  lip 
usually  expanded  or  thichened.  OperciUum  horny,  often  strengthened  by  a  thin  calcareous 
outer  layer.     Silurian  to  Recent. 

Graspedostoma  Lindström.  Globose,  narrowly  umbilicate,  with  short  spire,  and 
large  transversely  striated  or  cancellated  body  whorl.  Inner  lip  with  an  alar  process 
at  tlie  end  of  the  columella.     Silurian.     G.  elegantulum  Lindström. 

Grossostoma   Morr.  and   Lyc.   (Fig.   872).     Depressed   turbinate,   smooth,  without 


Fig.  872. 

Crossostoina  reflexi- 
läbrum  (d'Orb.). 
Middle  Lias ;  May, 
Calvados. 


Fig.  873. 

Liotia  ffervillei 
(Desliayes).  Calcaire 
Grossier ;  Haute- 
ville,  near  Valogne, 
F'rance. 


Fig.  874. 

Delphinula  segregata 
Heb.  et  Desl.  Callo- 
vian  ;  Montreuil  -  Bel- 
lay,  Maine-et-Loire. 


Fig.  875. 

Delphinula  scobina 
(Brongniart).  Oligocene  ; 
Gaas,  near  Dax,  France. 


urabilicus.     Spire  short,  aperture  round,  narrowed  by  a  callus.     Outer  lip  somewhat 
reflexed.     Trias  and  Jura. 

Liotia  Gray  (Fig.  873).  Depressed  turbinate,  with  transversa  swellings.  Aperture 
thickened  by  a  callous  rim.     Jura  to  Recent. 

Delphinula  Lam.  (Angaria  Bolt.)  (Figs.  874,  875).  Depressed  turbinate,  um- 
bilicate. Whorls  scaly,  spinous  or  spirally  ornamented.  Aperture  circular,  lip 
without  thickening.     Trias  to  Recent. 

VOL.  I  2  M 


530 


MOLLUSCA 


PHYLUM  VI 


Family  10.     Trochonematidae  Zittel. 

Shell  pyramidal,  turhinate  or  discoidal,  dextral  or  sinistral,  with  internal  nacreons 
layer.  JVhorls  convex,  with  one  or  more  longitudinal  Jceels,  and  slightly  undulating 
transversa  Striae  or  ribs.  Aperture  rounded,  sometimes  with  faint  notch.  Operculum 
unknown,  presumahly  horny.     Marine.     Cambrian  to  Cretaceous. 

This  extinct  group  is  very  abundant  in  tlie  Paleozoic,  and  notably  so  in  Jurassic 
rocks.  The  shells,  as  a  rule,  are  highly  ornamented,  and  have  been  associated  by  some 
with  the  Littorinidae,  by  others  with  the  Turbinidae  or  Purpurinidae.  They  form 
a  distinct  family,  which  is  best  placed  in  the  neighbourhood  of  the  Turbinidae  and 
Trochidae. 

Trochonema  Salter.  Pyramidal  to  turbinate,  deeply  umbilicate,  longitudinally 
keeled  and  transversely  striated.  Aperture  round  ;  the  umbilicus  surrounded  by  a 
keel.     Cambrian  to  Silurian. 

Eunema  Salter  (Fig.  876).  Pyramidal,  with  acute,  elongate  spire,  and  no  umbilicus. 
Whorls  with  two  or  more  spiral  keels,  and  strong  transverse  Striae.  Aperture  oval, 
slightly  notched  anteriorly.     Ordovician  to  Devonian. 


Fig.  876. 

Eunema  strigilata  Sal- 
ter. Ordovician ;  Pau- 
quette  Falls,  Canada. 


Fig.  877. 

Cydonema  bilix  Conrad. 
Ordovician ;  Cincinnati, 
Ohio. 


Ambcrleya  capitanea 
Münst.  Upper  Lias  ;  La 
Verpilliere,  near  Lyons, 
France. 


Cydonema  Hall  (Fig.  877).  Turbinate,  whorls  infiated  and  ornamented  with  fine 
Spiral  Striae ;  aperture  rounded,  peristome  discontinuous.     Ordovician  to  Devonian. 

Strophostylus  and  Holopea  Hall ;  Gyronema  Ulrich.  Ordovician  and  Silurian. 
Dyeria  Ulrich.     Ordovician.     Bucanospira  Ulrich.     Silurian. 

Amberleya    Morr.    and    Lyc.    (Eucyclus    Deslongch.)    (Fig.    878).       Turbinate    to 


Fig.  879. 

Platyacra  impressa 
(Schafhautl).  Lower 
Lias ;  Hoclifellen, 
ßavaria.  Cirrus  nodosus  Sowb. 

pyramidal,  with  deep  sutures,  and  no  umbilicus, 


Fio,  880. 
Lower  Oolite 


Yeovil,  England. 

Spiral  keels  usually  nodose  or  spiny. 


CLASS  IV 


GASTROPODA 


531 


and  crossed  by  strong  transverse  Striae,  which  are  more  numerous  in  the  lower  portion 
of  the  whorls  tlian  in  tlie  upper.  Aperture  rounded,  sometimes  witli  a  shallow  notch. 
Trias  to  Cretaceous  ;  common  in  all  divisions  of  the  Jura. 

Oncospira  Zitt.  Pyramidal,  spirally  ribbed,  with  one  or  two  transverse  swellings 
on  each  whorl,  disposed  continuously  along  the  spire.     Jura. 

Harausina  Gemni.  Sinistral,  with  nodose  longitudinal  keels,  and  no  umbilicus. 
Lias. 

Platyacra  v.  Amnion  (Fig.  879).  Like  the  last,  but  with  flattened  apex,  and  the 
earlier  whorls  discoidal.     Lias. 

Cirrus  Sowb.  (Scaevola  Gemm.)  (Fig.  880).  Sinistral,  turbinate  shells,  deeply 
and  widely  umbilicate.  Spire  acuminate  ;  whorls  spirally  keeled  and  striated,  and 
with  strong  transverse  ribs.     Trias  to  Middle  Jura. 

Family  11.     Trochidae  Adams. 

Shell  conical,  turhinate  or  pyramidalj  nacreous  internally.  Aperture  trapezoidal  or 
sub-circular,  peristome  disconnected,  inner  lip  often  hearing  a  tooth.  Base  more  or  less 
flattened  ;  operculum  thin,  horny.     Ordovician  to  Recent. 

Precise  determination  of  the  numerous  fossil  Trochidae  is  not  less  difficult  than 
that  of  the  Turbinidae.  Paleozoic  and  Mesozoic  forms  in  many  cases  do  not  harmonise 
with  recent  genera,  but  represent  rather  col- 
lective  types,  in  which  characters  now  distri- 
buted  amongst  several  genera  or  even  families 
are  united.  Shells  incapable  of  more  accurate 
determination  liave  been  commonly  assigned  to 
the  genus  Trochus.  Among  the  more  ancient 
true  Trochidae  may  be  mentioned  the  following : 
the  Trochus  species  described  by  Lindström 
from  the  Silurian  of  Gotland  ;  also  Flemingia 
and  Glyptohasis  de  Koninck,  and  Microdoma 
Meek  and  Worthen,  from  the  Carboniferous  ; 
Turhina  (Fig.  881)  and  Turhonellina  de 
Koninck,  ranging  from  the  Carboniferous  to 
the  Trias. 

Trochus  Linn.  (Fig.  882).  Shell  conical  or  pyramidal ;  whorls  slightly  convex  or 
flat ;  base  angular  at  the  periphery.  Inner  lip  often  truncated  anteriorly,  thickened 
or  with  teeth.     Silurian  to  Recent. 

Subgenera :   Tectus  Montf.  (Fig.  882) ;  Folydonta  Schum.  ;  Clanculus  Montf.,  etc. 

Monodonta  Lam.  (Figs.  883,  884).     Turbinate,  with  nearly  round  aperture,  the 


Turhina  spirulis 
Münst.  Keuper ;  St. 
Cassian,  Tyrol. 


Trochus  {Tectus)  luca- 
sanus  Brongt.  Oligo- 
cene ;  Castel  Gomberto 
near  Vicenza. 


Fig.  883. 

Monodonta  nodosa  Münst. 
Keuper  ;  St.  Cassian,  Tyrol. 


Fkj.  884. 


Monodonta  (Oxystele)  patukt 
Brocchi.  Miocene ;  Steina- 
brunn,  near  Vienna. 


Fi(i.  885. 


Gibhula  picta 
Eichwald.  Mio- 
cene; Wiesen, 
near  Vienna. 


Fir,.  886. 


Gihhula  brocchii 
Mayer.  Pliocene  ; 

Montopoli,  Tuscany. 


columella  ending  below  in  a  tooth. 
Phil.,  the  tooth  is  wanting. 


Trias  to  Recent.     In  the  subgenera  Osilinus  and 


.32 


MOLLUSCA 


THYLUM  VI 


Gihbula  Eisso  (Figs,  885,  886).     Turbinate  or  low  conical,  iinibilicate,  and  witli 
roiinded  apertiire.     Tertiary  and  Recent. 


Fig.  887. 

Calliostoma  semi- 
putictatum  Münst. 
Keuper ;  St.  Cas- 
sian,  Tyrol.    2/^. 


Calliostoma  aequalis 
Buv.  Coral-Rag ;  St. 
Mihiel;  Meuse. 


Fig.  889. 

Leimsiella  conica  (d'Orb.). 
Middle  Lias  ;  May,  Cal- 
vados. 


Fig.  890. 

Solariella  peregrina 
(Libassi).  Pliocene ;  Or- 
ciaiio,  Tuscaiiy. 


Fig.  891. 

Margaritcs  margaritula 
Mer.  Oligocene ;  Weinlieim, 
near  Alzey,  Baden. 


GalUostoma  Swains.  {Ziziphinus  Gray)  (Figs.  887,  888).     Conical,  with  peripheral 
keel  and  flattened  base.     Trias  to  Recent. 

Otlier  genera  are  Cantharidus  Montfort ;  Leivisiella 
Stol.  (Fig.  889);  Tegula  Lesson;  Solariella  Wood 
(Fig.  890) ;  Margarites  Leach  (Fig.  891)  ;  Danilia  Brus. 
(Fig.  892) ;  Gamitia  Gray,  and  many  others.  Most  of 
these  liave  a  more  or  less  extensive  Tertiary  liistory. 


Family  12.     Umtaoniidae  Adams. 


Fig.  892. 


Danilia  cZaiTiraia  (Etall.).    Coral-Rag 
Valfin,  Ain.    2/^. 


Shell  small,  usually  depressed  discoidal,  s7nooth  and 
lustrous,  or  ivith  fine  spiral  Striae,  and  without  nacreous 
layer.      Outer  lip  sharp,  peristome  discontinuous.      Um- 
bilicus  often  concealed  hy  a  callus ;  operculum  liorny.      Silurian  to  Recent. 

Allied    to   the   Recent  genera    Umbonium   Link  (Rotella   Lam.),    Tsanda   Adams, 


Fig.  893. 

^,         ,  Fig.  894. 

Chrysostoma 

acmon(d'Orh.).  Teinostoma    rotellae- 

Middle    Jura ;  formis  Desh.     Calcaire 

Baiin,        near  Grossier ;        Grignon, 

Cracow.  near  Paris. 


Helicocryptus  pusillus  (Roem.).    Coral- 
Rag  ;  Lindener  Berg,  near  Hannover. 


iFiG.  896. 

Adeorbis        tr 
Desh.      Middle 
(Auversien) ; 
Seine-et-Oise. 


icostatus 
Eocene 
Auvers, 


etc.,  are  a  nnmber  of  fossil  forms,  such  as  Pycnomphalus  Lindström,  from  the 
Silurian  and  Devonian  ;  Änomphalus  Meek  and  Worthen,  and  Rotellina  de  Koninck, 
from  the  Carboniferous  ;  Ghrysostoma  Swainson  (Fig.  893),  from  the  Jura,  and  others, 
which  are  probably  the  ancestors  of  the  Umboniidae. 

Whether  the  genera  Teinostoma  (Fig.  894)  and  Vitrinella  Adams,  together  with 
their  fossil  allies  from  the  Carboniferous  onward,  are  rightly  assigned  to  this  group,  is 
doubtful.  Helicocryptus  d'Orb.  (Fig.  895),  from  the  Jura  and  Cretaceous,  is  similar  to 
Vitrinella.  Gyclostrema  Marryat,  comprising  small,  lustrous  shells,  and  the  spirally 
Stria ted  ones  known  as  Adeorbis  S.  Woodw.  (Fig.  896),  present  some  resemblances  to 
the  Umboniidae ;  but,  according  to  Fischer,  they  form  separate  families.  All  of  these 
genera  have  fossil  representatives  in  the  Tertiary. 


CLA8S  IV 


GASTROPODA 


533 


Family  13.     Neritopsidae  Fischer. 

Shell  oval  to  semi-glohose,  with  short,  sometimes  laterally  twisted  spire,  and  without 
umbilicus  or  nacreous  layer.  Body  whorl  very  large ;  aperture  oval  or  semicircular, 
Inner  lip  calloas,  curved  and  occasionally  notched.  Operculum  calca- 
reous,  not  spiral,  with  suh-central  nucleus,  and  internally  lüith  callous 
colr.mellar  margin,  which  forms  a  hroad,  angular  or  rounded  process  in 
the  middle.      Devonian  to  Recent. 

The  Neritopsidae  are  distiiiguished  from  the  closely  related 
Neritidae,  principally  by  the  totally  ditferent,  non-spiral  operculum, 
and  by  the  fact  that  the  internal  partitions  are  not  resorbed,  as  in 
the  latter  family.  Detached  operciila  have  been  described  under  the 
nanies  of  Peltairon,  Scaphanidia,  Cyclidia  and  Rhynchidia. 

Naticopsis  M'Coy  {Neritomopsis  Waagen)  (Figs.  897-899).     Shell  oval  to  globose, 
sraooth    or    transversely  striated.      Aperture    oval ;    inner    lip    flattened,    somewhat 

A  B 


% 


Fio.  S97. 


Naticopsis  mandel- 
slohi  (Klipstein). 
Keuper ;  St.  Cas- 
sian,  Tyrol. 


A,  Naticopsis  ampliata  Phil.  Carboniferous  ;  Vise,  Belgium. 
B,  Operculum  of  N.  planispira  Phil.,  from  sarae  locality  (after  de 
Koninck). 


Naticopsis  lemniscata  Hoernes.  Trias  ; 
Esino,  Lombardy.  Original  coloration 
preserved. 


callous,  curved  and  sometimes  transversely  striated.  Sparse  in  Devonian,  but  very 
common  in  Carboniferous  and  Trias. 

Hologyra  Koken.  Semi-globose,  smooth,  with  faintly  impressed  sutures.  Spire 
short,  laterally  situated,  not  resorbed  internally.  Inner  lip  flattened,  callous,  covering 
the  umbilicus,  and  with  sharp  margin.  Abundant  in  the  Trias.  Some  species,  such 
as  H.  neritacea  (Münst.),  have  the  original  colouring  admirably  preserved. 

Marmolatella  Kittl.  Auriform  to  cap-shaped,  with  very  short,  incurved  and 
almost  marginal  spire.  Last  whorl  much  distended ;  inner  lip  callous,  broad, 
arched.     Trias.     M.  stomatia  (Stopp.),  M.  telleri  (Kittl). 

Natiria  de  Koninck.  Silurian  to  Carboniferous.  Palaeonarica  Kittl  (Pseudo- 
fossarus  Koken).  • 

Naticella  Münst.  (Fig.  900).  Thin-shelled,  depressed,  with  straight  spire,  and 
large,  transversely  ribbed  body  whorl.     Trias. 


Fio.  900. 
Naticella    costata    Münster. 
Upper  Trias;   Wengen,  Soutli- 
eru  Tyrol. 


Fio.  901. 


A,  Neritopsis  monillfoi-mis  Grat. 
Miocene  ;  Lapugy,  Transylvania.  B, 
N.  spinosa  Heb.  et  Deslong.  Callovian  ; 
Montnniil-Bellay,  Maine-et-Loire. 


Fio.  902. 


Operculum  of  Nerito]ms  raJiihi. 
Recent;  New Caledonia.  Bxternal 
and  int«'rnal  aspects  (aft«'r  Citisse). 


534 


MOLLUSCA 


PHYLÜM  V 


Platychilina  Koken  {Fossariopsis  Laube).  Spire  depressed,  straight ;  last  wliorl 
large,  surface  rough,  tuberciilose.  Inner  lip  even,  witli  simple  margin.  Trias.  P. 
pustulosus  (Münst.). 

Delphinulopsis  Laube.  Like  the  last,  but  spire  composed  of  loosely  connected 
whorls.  Sutures  deep.  Body  wborl  witli  nodose  longitudinal  keels.  Inner  lip  even, 
with  Sharp  margin.     Trias.     D.  hinodosa  (Münst.). 

Neritopsis  Grat.  (Figs.  901,  902).  Spire  depressed,  body  wliorl  very  large. 
Surface  witli  spiral  and  transverse  ribs  or  nodes,  often  cancellated.  Inner  lip 
tliickened,  witli  broad,  angular  emargination  in  the  middle.     Trias  to  Kecent. 


Family  14,     Neritidae  Lamarck. 

Shell  semi-glohose,  without  umhilicus  or  nacreous  layer.  Spire  very  short,  somewhat 
lateral;  whorls  rapidly  hroadening,  the  last  very  large,  and  earlier  ones  resorbed 
internally.  Aperture  semicircular  ;  margin  of  the  ßattened  or  calloused  inner  lip  often 
with  teeth.  Operculum  calcareous,  with  a  lateral  spiral  nucleus,  and  a  process  for 
muscle  attachment  on  the  inner  side.     Trias  to  Recent. 

The  Neritidae  are  partly  marine,  and  partly  fresh-water  inhabitants.  The  former 
live  usually  in  the  vicinity  of  the  coast,  the  latter  often  in  brackish  water.  Since  the 
earlier  whorls  are  internally  resorbed,  moulds  of  the  interior  reveal  no  trace  of  the  spire. 
This  character,  together  with  the  form  of  the  operculum,  serves  to  distinguish  the 
family  from  the  Naticopsidae,  from  wliich  both  it  and  the  terrestrial  Helicinidae 
are  probably  descended.  Fossil  forms  not  infrequently  retain  traces  of  tlieir  former 
coloration. 

Neritaria-  Koken  {Protonerita  Kittl).  Spire  acuminate,  suture  deej),  surface 
smootli.  Outer  lip  sharp  ;  inner  lip  callous,  flattened.  Resorption  of  the  inner  walls 
incomplete.     Trias. 

Nerita  Linn.  (Fig.  903).  Thick,  ovoid  or  semi-globose,  imperforate.  Surface 
smooth  or  with  spiral  ribs.  Inner  lip  callous,  flattened,  with  a  straight,  often 
denticulate  border.     Operculum  sub-spiral.     Trias  (?)  to  Recent. 

(?)  Oncochilus  Pethö  (Fig.  904).  Smooth  ;  inner  lip  arched,  callous,  bearing  two  or 
three  teeth  on  the  margin  or  smooth  ;  outer  lip  sharp.     Trias  and  Jura. 

Lissochilus  Pethö  (Fig.  905) ;  Neritodomus  Morr.  and  Lyc. ;  Neritoma  Morris. 
Jura.     Otostoma  d'Arch. ;  Dejanira  Stol.     Cretaceous. 

Velates  Montf.  (Fig.  906).  Depressed  conical,  only  the  curved  apex  of  the  spire 
Abc 


Fig.  903. 

A,  Nerita  laffoni  Merian.  Citharella  Limestone  ;  Bpfen- 
hofen,  near  Schaffliavisen,  Switzerland.  B,  N.  granulosa 
Desh.  Eocene  (Sables  Moyens);  Auvers,  near  Paris.  C, 
Operculum  of  a  recent  Nerita. 


Oncochilus  chromaticus  Zittel.     Upper 
Tithonian ;  Stramberg,  Moravia. 


visible.    Last  whorl  very  large.    Inner  lip  convex  or  straight,  with  denticulate  margin. 
Abundant  in  the  European  Eocene  ;  sometimes  attaining  a  size  of  10  or  12  cm. 

Neritina  Lam.  (Fig.  907).  Sniall,  semi-globose,  lustrous,  smooth  or  spiny,  mostly 
brilliantly  coloured.  Inner  lip  flattened,  with  sharp  or  fiiiely  toothed  margin  ;  outer 
lip  Sharp.  Inhabits  brackish  or  fresh  water.  Abundant  in  Tertiary  and  Recent.  The 
supposed  Mesozoic  forms  belong  principally  to  Nerita. 


CLASS  IV  GASTROPODA 

Püeolus  Sowb.  (Fig.  908).     Snicall,  cup-shaped  to 


Fig.  905. 


535 

conical,  ovoid  or  round. 


Lissochilus  sigaretinus  Buv. 
Coral-Rag ;  Hoheneggelsen,  Han- 
nover. 


Neritina  (iratelonpana  Fer. 
Mioceue ;  Häufelburg,  near  Günz- 
burg. 


Fig.  908. 
Püeolus  jilicatus  Sowb.    Bathon- 
ian  ;  Langrune,  Calvados,     ^/i- 


Fig.  906. 

Velates  schmidelianus  Cham.     Lower  Eocene 
(Londinien) ;  Cuise-Lamothe,  Oise. 


Apex  sliglitly  cvirved  backwards  ;  only  the  last  wliorl  visible.     Aperture  semicircular ; 
inner  lip  broad,  callous.     Jura  to  Eocene. 

Order  2.     CTBNOBRANCHIATA  Schweigger. 

{Pectinihranchia  Cuvier ;  Azygohranchia  von  Ihering ;  Monotocardia  Bouvier.) 

Right  cervical  gill  jJectinate,  very  large,  and  usually  transposed  to  the  left  side,  owing 
to  torsion  of  the  hody ;  the  left  gill  atrophied.  Heart  with  hut  one  auricle.  Radula 
smally  variously  constructed,  hut  usually  armed  with  fevj  teeth  in  a  transverse  series. 
Shell  coiled  in  a  more  or  less  elevated  spiral,  rarely  cup-  or  cap-shaped. 

The  Ctenobrancliiata  constitute  the  largest  group  of  the  Streptoneura.  They  are 
for  the  most  part  marine,  but  some  are  terrestrial,  and  some  inhabit  fresh  water. 
Beginning  in  the  Sikirian,  they  attain  their  maximum  distribution  in  the  Mesozoic, 
Tertiary  and  Recent  periods,  A  division  into  two  groups — Holostomata  and  Siphono- 
stomata — according  to  the  nature  of  the  aperture,  has  been  attempted  ;  but  this  is 
unnatural,  since  it  emphasises  a  shell  character  whicli  is  unaccompanied  by  any 
anatomical  differences.  Classifications  based  upon  the  structure  of  the  radula,  such  as 
have  been  proposed  by  Troschel,  and  more  recently  by  Bouvier,  are  valueless  in 
Paleontology.  Here  it  will  be  sufficient  to  recognise  two  suborders  primarily : 
Platypoda,  in  which  the  foot  is  typically  developed  ;  and  Heteropoda^  in  which  it  is 
modified  into  a  fin. 


Suborder  A.     HETEROPODA  Lamarck. 

{Nucleohranchiata  Blainville.) 

To  the  Heteropoda  belong  naked   or  shell-covered,   free-swimming  and   pelagic 
marine  MoUusks,  with  distinct  liead  and  highly  developed  sense  organs.     Heart,  gills, 


536 


MOLLUSCA 


PHYLÜM  VI 


reproductive  organs  and  nervous  System  agree  with  tlie  correspondiiig  organs  of  the 
Ctenobranchiates ;  tlie  radula  resembles  that  of  tlie  Taenioglossa.  Tliey  differ  con- 
siderably,  however,  from  the  Prosobrancliiates,  since  the  foot  is  modified  into  a  sort  of 
vertical  fin,  and  imparts  to  them  a  peciüiar  appearaiice.  They 
rise  usually  toward  evening  in  great  swarms  to  the  surface  of 
the  ocean,  where  they  hover  about  with  a  very  rapid  motion, 
swimming  in  an  inverted  position,  with  the  dorsal  side  down, 
and  the  foot  uppermost.  They  are  exceedingly  delicate,  often 
transparent  organisms,  The  body  may  be  either  entirely 
naked  or  provided  with  a  very  thin,  light  shell. 

Two  Recent  genera  have  been  found  also  in  early  Tertiary 
deposits.  Of  these  Garinaria  Lamarck,  has  a  keeled,  cap-shaped, 
glassy  shell ;  while  in  Atlanta  Lesson  (Fig.  909),  the  delicate 
shell  is  coiled  spirally  in  a  single  plane,  and  the  apertiire  is  provided  with  a  slit. 
Owing  to  a  similarity  in  coiling  of  Atlanta  and  Oxygyrus  to  that  of  the  Paleozoic 
Bellerophontidae,  a  relationship  between  the  two  has  been  suggested.  The  latter 
forms  are  distinguished  by  their  heavier,  thicker  shells,  but  are  very  pi'obably  related 
to  Emarginula  and  its  allies. 


Fio.  909. 

Atlanta  peronii  Lesueur. 
Recent ;  Atlantic  Ocean. 


Suborder  B.     PLATYPODA  Lamarck. 


Fig.  910. 


Superfamily  1.     GYMNOGLOSSA  Gray. 

Mostly  Jiolostomate  forms,  in  which  the  radula  is  usually  unarmed  through  degenera- 
tion.      The  smaller  forms  frequently  parasitic  or  commensal. 

Family  1.     Eulimidae  Fischer. 

Small,  polished,  elongate-conic  shells,  with  ovate  aper- 
tures ;  the  axis  often  ddstorted,  protoconch  dextral.  Trias 
to  Recent. 

Eulima  Risso  {Melanella  Bowdich)  (Fig.  910).  Tur- 
reted,  smooth,  lustrous,  without  umbilicus.  Trias  to 
Recent. 

Niso  Risso  (Fig.  911).  Like  the  last,  but  with  deep 
umbilicus  reaching  to  the  apex.     Trias  to  Recent. 

A,  Eulima  suh 
ulata  Don.    Plio 

Family  2.     Pyramidellidae  Gray.  cene ;  Coroncina 

Tuscany.     B,  E. 

Shell    turreted    to    elongate-oval.      Aperture    oval,    an-  poiita     (Linn.), 
teriorly  rounded,  or  angular ;  outer  lip  sharp.      Operculum   leis,  Moravin. 
horny,  spiral.     Marine.     Cambrian  to  Recent. 

The  protoconch  consists  of  several  whorls,  and  in  Paleozoic  and  Mesozoic  forms  is 
coiled  in  the  same  direction  as  the  remainder  of  the  shell.  But  in  the  younger  and 
more  typical  genera  it  is  heterostrophic,  distinctly  separated  from  the  rest  of  the 
shell,  and  often  Stands  at  an  angle  with  the  adult  spire.  It  is  questionable  whether 
forms  older  than  the  Cenozoic  can  be  retained  in  this  family ;  Fischer  places  most  of 
thent  in  a  new  family,  entitled  Pseudomelaniidae. 

Macrocheilus  Phil.  {Macrochilina  Bayle  ;  Strohaeus  de  Kon.)  (Fig.  9 1 2).  Elongate- 
oval,  without  umbilicus,  smooth  or  with  slightly  curved  growth-lines.  Spire  acuminate, 
only  moderately  high ;  last  whorl  large.  Aperture  angular  posteriorly,  sometimes 
also  in  front.     Inner  lip  with  weak  anterior  folds.      Silurian  to  Trias. 

(?)  Ptychostoma  Laube  ;  (?)  Undularia  Koken.     Trias. 

Loxonema  Phil.     Turreted,  whorls  arched,  with  S-shaped  growth-lines.     Sutures 


Fig.  911. 

Niso  eburnea 
Risso.  Plio- 
cene ;  Monte 
Mario,  near 
Rome. 


CLASS  IV 


GASTKOPODA 


537 


Silnrian  to  Trias  ;  paiticiilarly 


deep ;  aperture  higlier  tlian  wide,  with  shallow  canal. 
abundaiit  in  tlie  Carboniferoiis. 

Zygopleura    Koken.      Like    the    last,    but   whorls    with    sharp,    sliglitly    curved 
transverse  ribs,  or  transverse  nodose  keel.     Devonian  to  Lower  Cretaceoiis. 

Bourgetia  Deshayes  {Pithodea  de  Kon.).  Lai-ge, 
elongate-oval  to  turreted,  with  large,  inflated  body 
whorl.  Snrface  marked  with  spiral  Striae  or  furrows. 
Carboniferous  and  Upper  Jura. 

Pseudomelania  Pictet  {Chemnitzia  p.p.  d'Orbigny) 
(Fig.  913).  Turreted,  with 
numerous,  ahnost  flat  whorls, 
and  slightly  impressed  sutures. 
Snrface  smooth,  or  marked  by 
fine  growth-lines ;  aperture 
rounded  anterioiiy,  or  with 
faint  canal.  Unibilicus  want- 
ing;  rarely  an  umbilical  fissure 
present.  Very  abundant  in  the 
Trias  and  Jura,  less  so  in 
Cretaceous  and  Eocene  ;  prob- 
ably  present  also  in  the  Car- 
boniferous. 


Siibgenera :  Oonia,  Microschiza 
Geram. ;  Hypsipleura,  Anoptychia 
Koken.  Trias  and  Jura.  Coe- 
lostylina,  Eiistylus,  Spirostylus 
Kittl.  Trias.  Bayania  Munier- 
Chalm.  (Fig.  914).    Eocene. 


Fio.  912. 
Macroclieilus      arculatus 
(Schloth.).      Middle     De- 
vonian ;      Paffrath,     near 
Cologne. 


Fio.  913. 

Pseudomelania 
heddingtonensis 
(Sowb.).  Oxford- 
ian ;  France.  Bands 
of  original  colora- 
tion  still  showing. 


Fig.  914. 

Pseudomelania 
(Bayania)  lactea 
Lam.  sp.  Cal- 
caire  Grossier ; 
Grignon,  near 
Paris. 


Pustularia    Koken,  non   Swains.     Turreted,  with  groove-like  sutures.     WhorLs 
flat,  with  three  or  more  spiral  rows  of  nodes.      Trias. 

Gatosira  Koken.       Whorls  flat,  with  transverse  ridges.       Aperture  canaliculate ; 

base  with  spiral  grooves.     Trias  and  Jura. 

Biastoma  Desh.  (Fig.  915).  Like  the  last, 
but  aperture  separated  from  the  body  whorl. 
Whorls  with  transverse  folds  and  spiral  Striae. 
Cretaceous  to  Recent. 

Mathilda  Semper  {Promathilda  Andreae). 
Turreted ;  whorls  transversely  and  spirally 
striated  or  ribbed.  Aperture  with  canaL  Proto- 
conch  heterostrophic.     Jura  to  Recent. 

Keilostoma  Desh.  {Paryphostoma  Bayan)  (Fig. 
916).  Turreted,  spirally  striated.  Outer  lip 
with  externally  thickened  margin.     Eocene. 

Turbonilla  Risso  {Chemnitzia  p.p.  d'Orb.)  (Fig. 
917).  Small,  turreted,  with  heterostrophic  proto- 
conch.  Whorls  transversely  ribbed  or  smooth. 
Inner  lip  straight,  or  occasionally  with  folds. 
Tertiary  and  Recent. 

Odostomia  Fleming  (Fig.  918);    Pyramidella 

Lamarck     (Fig.     919).      Cretaceous     to     Recent. 

Tertiary  and  Recent.    Palaeoniso  Gemm.     Trias 


Fig.  915. 

Diastema  costcllata 
(Lam.).  Calcaire 
Grossior ;  Daniery, 
near  Bpernay. 


Syrnola  Adams 
and  Jura. 

The  genera 


Fig.  916. 

Keilostoma  turricula 
Brug.  sp,  (Melania 
margiimta  Lamarck). 
Calcaire  Grossier ; 
Grignon,  near  Paris. 

Eidimella  Fischer. 


Suhulites  Conrad  (?  Pohjphemopsis  Portlock),  from  the  Cambrian  t^ 


538  MOLLUSCA  phylum  vi 

Carboniferous ;     Fusispira    Hall,    Ordovician  ;    and    Soleniscus    Meek   and    Wortlien, 


Fio.  917. 

Turbonüla  rufa 
Phil.  Crag;  Sutton, 
England. 


Fig.  918. 
Odostomia  pli- 
cata (Montf.). 
Upijer  Oligocene ; 
Nieder-Kaufungen, 
near  Cassel. 


Fig.  919. 

Pyramidella  pli- 
cosa  Bronn.  Mio- 
cene ;  Niederleis, 
Moravia. 


Fig.  920. 

Euchrysalis  fusi- 
formis  (Münster). 
Kenper ;  St.  Cas- 
sian,  Tyrol. 


Carboniferous,  are  cliaracterised  by  narrow,  anteriorly  elongated  and  canaliculate  aper- 
tures.  They  probably  form  a  separate  family,  in  which  also  sliould  be  placed  the 
Triassic  Euchrysalis  Laube  (Fig.  920). 

Superfamily  2.     PTENOGLOSSA  Gray. 

Teeth  of  the  radula  suhulate,  numerous  and  similar  in  each  transverse  row. 


Family  1.     Epitoniidae,  novum  (Scalariidae  Broderip). 

Shell  turreted,  usually  narrowly  umhilicate.  Whorls  convex,  transversely  rihbed  or 
striated.  Aperture  round,  with  entire  peristome.  Operculum  horny,  paucispiral. 
Marine.     Sikirian  to  Recent. 

Holopella  M'Coy  {Aclisina  de  Kon.).  Slender,  turreted  ;  whorls  witli  fine  trans- 
verse Striae,  sometimes  cancellated.     Silurian  to  Carboniferous. 

Gallonema  Hall  {Isonema  Meek  and  Worth.).  Turreted,  oval  to 
globose ;  whorls  covered  with  lamellate  transverse  ribs ;  aperture 
circular.     Silurian  and  Devonian. 

Scoliostoma  Braun.  Devonian.  Chilocyclus  Bronn  {Gochlearia 
Braun) ;   Ventricaria  and  Batycles  Koken.     Trias. 

Epitonium  Bolten  {Scalaria  Lam. ;  Scala  Klein ;  Cirsotrema 
Mörch)  (Fig.  921).  Turreted;  whorls  strongly  arched,  with  trans- 
verse ribs,  and  often  also  spirally  striated.  Aperture  round,  outer 
lip  sometimes  thickened.     Trias  to  Recent.     Many  subgenera. 

Family  2.     Solariidae  Chenu. 

Fk;.  921. 

Scalaria  lamellosa  Shell    depressed    conical,    deeply    and   hroadly   umhilicate,   without 

Brocchi.  Miocene ;  nacreous     lauer,       Whorls 

Baden,  near  Vienna.  ,  '^       ,  , 

anguiar  ;  operculum  horny 

or    calcareous    spiral.       The  protoconch    is 

heterostrophic.      Marine.      Cretaceous      to 

Recent. 

The  Solariidae  exhibit  some  resem- 
blance  to  the  Euomphalidae,  from  which 
they  are  distinguished  principally  by  the 
heterostrophic  protoconch.  ^^^^.^^^  ^.^^^^^^ 

Solarium  Lam.  {Architectonica  Bolten)    Bronn.      Miocene; 
(Figs.  922,  923).     Aperture  quadrilateral ;    Niederleis, Moravia. 
operculum  horny  ;  umbilical  angle  notched  or  sharp.     Jura  to  Recent.     A  number 
of  Mesozoic  forms  confused  with  this  genus  probably  belong  to  Euomphalus. 

Torinia  Gray.     Tertiary  and  Recent.     Bifrontia  Desh.  {Omalaxis  Desh.).     Eocene. 


Fig.  923. 

Solarium  leymeriei  Ryckholt. 
Tourtia  (Cenomanian) ;  Tour- 
nay,  Belgium. 


CLA8R  TV 


GASTROPODA 


539 


Superfamily  3.     TAENIOGLOSSA  Bouvier. 

Teeth  of  the  radula  seven  in  each  transverse  roiv.     Mainly  holostomate  forms,  hat 
some  (jenem  have  deeply  notched  apertures,  as  in  the  higher  divisions. 

Family  1.     Purpurinidae  Zittel. 

Thick-shelled,  oval,  with  platform-like  spire,  and  with- 
out  pearly  layer.  TVJiorls  flattened  heneath  the  suture  and 
angular,  the  angles  often  heset  with  nodes.  Body  whorl 
large ;  aperture  oval,  with  anterior  emargination,  and 
discontinuous  peristome.  Operculum  unknown.  Carboni- 
feroiis  to  Cretaceous. 

Trachydomia  Meek  and  Worth.  {Trachynerita  Kittl). 
Goal  Measures  ;  North  America  and  Europe.  Pseudoscalites 
Kittl ;   Tretospira  Koken.      Trias  ;  Europe. 

Purpurina  d'Orb.  Elongate-oval.  Whorls  angiilar 
superiorly,  sj)irally  ribbed,  with  transverse  folds  or  costae, 
highly  ornamented,  often  with  umbilical  fissure.  Aperture 
oval,  anteriorly  notched.     Rhaetic  and  Jura.  Furpuroidm    noduiata   (Young 

n  -TT         j.i.  /ny-      r\  n  A  \       c<    •  •  J.^  •         and  Bird).    Great  Oolite ;  Minchin- 

Furpuroidea  Lycett  (Fig.  924).     Spire  with  successive  hampton,  England. 
Steps  or  platforms,  the  flattened  surface  beneath  the  suture 

bounded  by  a  row  of  nodes.     Last  whorl  inflated,  smooth.     Aperture  anteriorly  with 
canal-like  notch  ;  outer  lip  thin.     Jura  and  Gretaceous. 

Brachytrema  Morris  and  Lycett ;  Tomocheilus  Gemm.     Jura. 


Fig.  924. 


Family  2.     Littorinidae  Gray. 

Shell  turhinate,  usually  smooth  or  spirally  ornamented,  without  nacreous  layer. 
Aperture  rounded ;  outer  lip  sharp.  Operculum  horny,  paucispiral.  Marine. 
Ordovician  to  Recent. 

Fossil  Shells  of  this  family  are  distinguished  solely  from  those  of  the  Turbinidae 

and  Trochidae  by  the  absence  of  a  pearly  layer.     The  animal, 

however,  differs  radically.     The  heart  has  but  one  auricle  in 

the  Littorinidae,  two  in  the  Turbinidae  and  Trochidae.     The 

radula    in  the  last-named  groups  is  rhipidoglossate ;    in  the 

present  family  it  is  taenioglossate.     The  differences.in  essen tial 

structure    are   thus  seen  to  be   considerable ;    yet   the  sliells 

when  fossilised  are  so  similar,  it  can  scarcely  be  doubted  tliat 

the  so-called  Paleozoic  Littorinidae  are  in  many  cases  very 

closely    related    to    genera  referred    to    the    Turbinidae    and 

Trochidae.     The  limits  of   these  families  are  therefore  very 

Ym,  925.  uncertain,  so  far  as  Paleozoic  forras  are  concemed.     Among 

Turhoniteiia      subcostafa   the  extinct  genera  which  exhibit  great  similarity  to  Littorina, 

(^"i^^f;)-    Middie  üevonian ;   j^^^;  are  often  assigned  to  the  above-named  families,   may  be 

Paffrath,  near  Cologne.  ,        ,         „°,       .  „  ,  xx  n  r\   j       •   •  ^ 

mentioned  the  followmg :  Holopea  Hall.  Ordovician  to 
Devonian.  Turhoniteiia  de  Koninck  (Fig.  925).  Devonian  and  Carbonil'.ioii>. 
Portlockia,  Turhinilopsis  and  Rhahdopleura  de  Koninck.  Lower  Carboniferous. 
Lacunina  Kittl.     Tiias. 

Littorina  Fer.  (Fig.  926).  Thick-shelled,  turbinate  to  globose,  smooth  or  s])ii-al]y 
striated,  without  umbilicus.     Aperture  oval.     Jura  to  Recent. 


540 


MOLLUSCA 


PHYLUM  VI 


Lacuna  Tiirton  (Fig.  927).     Like  the  last,  biit  thiii,  small,  with  an  excavated  pillar. 
Tertiary  and  Recent. 


Fi(f.  926. 

Littorina  litorea  (Linn.). 
Post-Pleistocene ;  Isle  of 
Skaptö. 


Fig.  927. 

Lacuna  (?)  basterotina 
Bronn.  Miocene ;  Stein- 
abrunn,  near  Vienna. 


Fig.  92 


Fossarus  costatus  Brocchi.     Pliocene  : 
Limite,  Tuscany. 


Lacunella  Desli.  Eocene.  Litiopa  Rang  ;  Planaxis  Lam. ;  Quoijia  Desh.  Tertiary 
and  Recent.     The  families  Litiopidae  and  Planaxidae  are  usually  recognised. 

The  genns  Fossarus  Phil.  (Fig.  928)  forins,  according  to  Fischer,  a  separate  family, 
Fossaridae.     It  occiirs  in  the  late  Tertiary  and  Recent. 


Family  3.     Cyclostomatidae  Menke. 

Shell  extremely  variable  in  form,  turhinate  to  discoidal,  sometimes  turreted,  covered 
with  epidermis.  Äperture  circular,  with  usually  entire  peristome.  Operculum  horny  or 
calcareous,  spiral.     Terrestrial.     Cretaceous  to  Recent. 

Like  the  pulmonate  snails,  the  animal  possesses  a  respiratory  cavity,  But  in 
other  respects  they  apjDroach  the  Littorinidae  very  closely,  which  latter  forms  also 
have  the  gill  much  reduced.  The  shell  habit  is  excessively  variable.  Tliere  are  more 
than  600  Recent  species  distributed  throughout  all  parts  of  the  globe,  but  the  majority 


Fig.  929. 

Cydostoma  hi- 
sulcatum  Zieten. 
Miocene ;  Ermin- 
gen,  near  Ulm, 
Würtemberg. 


Fig.  930. 

Pomatias  labellum 
(Thoraas).  Helix 
Beds  (Upper  Oligo- 
cene);  Hochheim, 
near  Wiesbaden. 


Fig.  931. 

Cydotus  exaratus  Sandb. 
Upper  Eocene ;  Pugnello, 
Italy.  Shell  and  operculum 
(after  Sandberger). 


Fig.  932. 

Strophostoma  anom- 
phala  Capellini.  Oligo- 
cene ;  Arnegg,  near 
Ulm,  Würtemberg. 


of  tliese  are  tropica!  Fossil  forms  are  found  in  fresh-water  deposits  as  old  as  the 
Middle  Cretaceous. 

Gyclostomus  Montf.  (Fig.  929).  Turbinate,  with  calcareous  spiral  operculum. 
Tertiary  and  Recent. 

Otopoma,  Tudora  Gray.     Tertiary  and  Recent. 

Megalomastoma  Guild.  Turbinate  to  chrysalis-shaped,  usually  smooth.  Peristome 
with  thick  margins ;  outer  lip  reflected.  Operculum  horny.  Cretaceous  to  Recent. 
M.  mumia  (Lamarck). 

Pomatias  Studer  (Fig.  930).  Turreted,  transversely  striated,  with  reflected 
margins  and  calcareous  operculum.     Tertiary  to  Recent ;  palearctic. 

Leptopoma  Pfeiff.;  Gijclophorus  Montf.;  Graspedopoma  Pfeift'.;  Gyclotus  Guilding 
(Fig.  931),  etc.  Upper  Cretaceous.  These  genera  are  considered  to  form  a  distinct 
family,  Gyclophoridae.     Strophostoma  Desh.  (Fig.  932).      Upper  Cretaceous  to  Miocene. 


CLASS  IV 


GASTßOPODA 


541 


Family  4.     Oapulidae  Cuvier. 

Shell  cu2J-f  ca])-shai)ed  or  oval,  irregulär^  with  spirally  twisted  apex ;  in  some  cases 
the  shell  is  comjwsed  of  several  depressed  whorls.  Body  whorl  very  large  ;  aperture  wide  ; 
operculum  absent.     Marine.     Cambrian  to  Receiit. 

Various  genera  beloiiging  liere  are  stationary,  remaining  througliout  nearly  the 
wliole  of  tlieir  existence  attached  to  some  foreign  body,  to 
wliich  tliey  gradually  become  accommodated  in  form. 

Stenotheca  Salter.  Shell  small,  cap-shaped,  concentrically 
striated  or  fiirrowed,  with  slightly  incurved  apex,  whicli 
latter  is  distantly  situated  posteriorly.     Lower  Cambrian. 


Capulus  hungaricus  (Linii.). 
Pliocene ;  Tuscany. 


Fig.  934. 

Capulus  rugosus  (Sowb.). 
Great  Oolite ;  Langrune, 
Calvados,     i  'i 


Fig.  935. 

OrthonycMa  elegans  Barr. 
Silurian  (Etage  E) ;  Lochkow, 
Bohemia. 


Capulus  Montf.  (Pileopsis  Lam.;  Brocchia  Bronn)  (Figs.  933,  934).  Irregularly 
conical  or  cap-shaped  ;  apex  greatly  displaced  backward,  more  or  less  spirally  inroUed. 
Aperture  wide,  rounded  or  irregulär  ;  internally  with  a  horseshoe-shaped  muscular 
Impression.  Exceedingly  abundant  from  the  Cambrian  to  Carboniferous,  but  rather 
sparse  from  the  Trias  onward. 

Orthonychia  Hall  {Igoceras  Hall)  (Fig.  935).  Shell  conical,  straight  or  slightly 
curved,  often  plicated.     Apex  but  faintly  spiral.     Silurian  to  Carboniferous. 

Platyceras  Conrad  {Acroculia  Phil.)  (Fig.  936).     Apex  bent  and  spirally  inroUed. 


Platyceras  neritoides   Phil. 
Carboniferous  ;  Vis6,  Belgium, 


Diaphorostoma 
Hall.  Silurian ; 
Indiana. 


:.  93^. 

Horiostoma  harrandci  Mun.-Chalm. 
Lower  Devonian ;  Gahard,  lUe-et- 
Vilaine  (after  Munier -Chalmas). 


Surface  smooth,  striated,  plicated  or  covered  with  small  spines.  Young  shell  coiled 
as  in  Diaphorostowa,  late  stages  non-coiling,  often  spinous.  Commensal  on  Echinoids. 
Silurian  to  Coal  Measures. 

Diaphorostoma  Fisher  {Platyostoma  Conrad)  (Fig.  937).  Shell  composed  of  numerous 
rapidly  widening  whorls.  Spire  low,  body  whorl  very  large.  Inner  lip  reflected  and 
somewhat  thickened.     Aperture  round,  of  large  size.     Silurian  to  Carboniferous. 

Horiostoma  Munier-Chalm.  (Fig.  938).  Shell  ihick,  spirally  ribbed,  with  short 
lateral  spire,  and  wide  umbilicus.     Devonian. 

Tuhina  Barr.     Silurian.     Rothpletzia  Simonelli.     Tertiary. 


542 


MOLLUSCA 


PHYLÜM  VI 


Hipponix  Defr.  (Gochlolepas  Klein)  (Fig.  939).  Shell  tliick,  obliquely  conical  to 
cup-shaped.  Beak  straiglit,  rarely  spiral,  greatly  removed  pos- 
teriorly.  Aperture  oval  or  rounded,  internally  with  a  horseslioe- 
shaped  miiscular  imj)ression.  The  foot  often  secretes  a  thick, 
operculiform  calcareoiis  disk.     Cretaceous  to  Kecent. 


Hipponix  cornucopiae  (Lamarck.)  Calcaire 
Grossier;  Liancourt,  near  Paris.  A,  Shell. 
B,  Foot-plate. 


Fig.  940. 

Calyptraea  (Trochita)  trocJiiformis  Lam.    Calcaire  Grossier ; 
Damery,  near  Epernay. 


Calyptraea  Lam.  {Galerus  Gray)  (Fig.  940).  Shell  thin,  conical,  with  central 
Spiral  apex.  AVhorls  flattened,  often  spinöse.  Base  horizontal : 
aperture  wide,  depressed.     Cretaceous  to  Eecent. 

Grepidula  Lam.  (Fig.  941).  Slipper -shaped,  elongate-oval,  flat 
or  arched.  Beak  at  the  posterior  end,  almost  marginal,  somewhat 
curved.  Aperture  greatly  elongated,  wide ;  inner  lip  formed  by  a 
thin  horizontal  lamella.     Cretaceous  to  Eecent. 

Crucihulum  Schum.     Tertiary  and  Recent. 


Family  5.     Naticidae  Forbes. 

Fig.  941.  Shell  with  short  spire  and  large  hody  whorl.     Aperture  semicircular 

Crepiduia  ungui-  to  oval,  angular  posteriorly,  hroadly  rounded   anteriorly.      Operculum 
ceneT  Tu^cany.  ^°"   calcareous  or  horny,  paucispiral.     Marine.     Trias  to  Recent. 

The  distinction  of  fossil  Naticidae  from  Naticopsis,  Nerita  and  Ämpullaria  is 
attended  with  some  difßculty,  since  they  frequently  possess  nearly  identical  characters 
in  common,  differing  mainly  in  the  operculum,  whicli  is  not  preserved  fossil. 

Sinum   Bolten   {Sigaretus  Lam.)  (Fig.   942).      Shell  depressed,  auriform,  spirally 


Fig.  942. 

Sinum  haliotoideum 
(Linn.).  Miocene ;  Grund, 
Hungary. 


Fig.  943. 

A,  Natica  millepunctatu  Lam, 
Pliocene ;  Monte  Mario,  near  Roma. 
-B,  Operculum  of  N.  multipunctata 
S.  Woodvv.     Crag  ;  Sutton. 


Fig.  944. 

Natica  (Ampullina)  patula 
Lam.  Calcaire  Grossier ; 
Damery,  near  Epernay. 


striated  or  furrowed.     Spire  very  low,  with  rapidly  widening  whorls.     Aperture  greatly 
distended  ;  operculum  horny.     Tertiary  and  Recent. 

Natica  Scopoli  (Figs.  943-946).     Globose,  semi-globose,  ovate  or  pyramidal,  smooth 
and   lustrous,   rarely   spirally    striated,    umbilicate    or    not.     The    umbilicus,    when 


GASTROPODA 


543 


jiresent,  often  iiartially  or  entirely  filled  witli  calliis.     Aperture  semicircular  or  oval. 
Outer  lip  sliaip  ;  inner  lip  thickened  by  a  callus.     Excessively  abundant  from  the 

Trias  onward. 

Subgenera  :  Ampullina  Lam.  (Fig.  944)  ; 
Amaurojysis  Mörch.  (Figs.  945,  946)  ;  Polinices 
Montfort ;  Euspira  Agassiz  ;  Lunatia,  Cernina 
Gray  ;  Neverita  Risso,  etc. 

(?)  Deshayesia  Raul. 
(Fig.  947).  Like  Natica, 
but  inner  lip  witb  a 
thick  callus  and  den- 
ticulated.  Miocene  and 
Pliocene. 


Family  6. 

Xenophoridae 

Deshayes. 

Shell  turbinate^  with- 
out  nacreous  layer ; 
whorls  flat,  often  covered  with  agglutinated  foreign  hodies.  Base  concave  or  flat,  with 
a  peripheral  keel.  Aperture  ohliquely  quadrilateral.  Operculum  horny.  Silurian  to 
Recent. 


Fig.  945. 


Natiai  {Ampullina) 
loülemetl  Lam.  Cal- 
caire  Grossier;  Da- 
mery,  near  Epernay. 


Fig.  946 


Natica  (Amauropsis) 
biilbiformis Sowh.  Upper 
Cretaceous ;  St.  Gilgen 
on  Wolfgangsee,  Austria. 


Deslutyesia  cochUaria 
(Brongniart).  Oligocene ; 
Monte  Grumi,  near 
Vicenza. 


The  Xenophoridae  are  an  ancient  family,  the  modern  representatives  of  which 
have  acquired  a  high  differentiation.  The  radula  is  like  that  of  the  Capulidae, 
Littorinidae  and  Strombidae,  not  like  that  of  the  Trochidae.  The  earlier  forms, 
encountered  in  the  Silurian,  present  a  great  superficial  resemblance  to  the  Paleozoic 
Trochus  species, 

Eotrochus  Whitfield  (Fig.  948).  Thin-shelled,  turbinate,  widely  umbilicate. 
Whorls  flat,  rarely  with  aggluti- 
nated foreign  particles.  Base  con- 
cave, its  periphery  formed  by  a 
compressed  lamellar  belt.  Silurian 
to  Recent. 

Omphalopterus  Roemer.  De- 
pressed  turbinate,  widely  umbili- 
cate. The  wide  peripheral  margin 
at  the  base  composed  of  two  lamellae, 
separated  by  a  slit.     Silurian. 

Glisospira  Billings ;  Autodetus 
Lindström.      Silurian. 

Xenophora  Fischer  {Phorus 
Montf.)  (Fig.  949).     Low  trochiform,  narrowiy  umbilicate. 


Fig.  949. 


Eotrochus  heliacus 
(d'Orb.).  Upper  Lias ;  La 
Verpilliere,  near  Lyons. 


Xenopliora  agglutinans  (Lam.). 
Calcaire  Grossier  ;  Damery,  near 
Epernay, 

Whorls  usuallv  covered 


above  with  agglutinated  extraneous  objeots.     Cretaceous  to  Recent. 


Family  7.     Ampullariidae  Gray. 

This  family  inhabits  fresh  or  brackish  water,  and  is  found  in  Africa,  Asia  and 
tropical  America.  Some  of  their  shells  are  hardly  to  be  distinguished  from  Ampul- 
lina. The  animal  possesses  a  lung  cavity  above  the  riglit  gill.  Fossil  forms  occur  in 
fresh -water  deposits  of  Cretaceous  age  at  Rognac,  near  Marseilles,  and  also  in  the  early 
Tertiary. 


544 


MOLLUSCA 


PHYLUM  VI 


Family  8.     Valvatidae  Gray. 

Shell  composcd  of  few  ^vhorls,  conical  or  discoidal,  umhilicate.  Ajjerture  round,  with 
continuous  'peristome.  Opercuhim  horny,  circular,  multisjjiral. 
Upper  Jura  to  Kecent. 

The  genus  Valvata  Müll.  (Fig.  950)  is  small,   and  varies 

froiu  turbinate  to   discoidal.     It  comprises  about  twenty-five 

Fio.  950.  Eecent    species,  inliabiting  tlie  fresh   waters    of   Eiirope    and 

Valvata  piscinaiis  Müll.    Nortli  America,     It  is  initiated  in  tlie  Purbeck,  biit  does  not 

?ransVivanr''''    ^^'^^''   become  at  all  abundant  until  tlie  Tertiary. 


Family  9,     Viviparidae  Gill. 

Shell  conical  or  ttirhinate,  with  thick  epidermis ;  imjyerforate  or  with  narrow 
umhilicus.  Whorls  smooth,  tubulär  or  angular.  Äpertiire  rounded,  oval,  suh-angular 
posteriorly,  with  continuous  peristome.  Operculum  horny,  concentrically  striated,  with 
eccentric  nucleus.     Jura  to  Eecent. 


Tliis,   tlie    principal  genus,   is 
G  D 


Vivipara    Montf.   [Paludina    Lam.)   (Fig.    951). 
abundant  in  fresh  water  a  b 

of  all  parts  of  the  globe, 
with  the  exception  of 
tropical  and  South 
America.  Several  other 
genera  and  subgenera 
are .  recognised,  such  as 
Gampeloma  Kaf.  (Me- 
lantho  auct.)  of  North 
America,  comprising 
mostly  smooth,  thick- 
shelled  species,  with 
thickened  inner  lip ; 
Tulotoma  Haldem.,  including  forms  with  angular  whorls,  North  America  ;  Margarya 
Nev.,  China  ;  Lioplax  Troschel ;  Laguncula  Benson  ;  Tylopoma,  Boshovicia  Brusina,  etc. 

Typical  species  of  this  genus  are  found  in  the  Wealden  clays.  Vast  numbers  of 
Vivipara  occur  in  the  Pliocene  of  southern  Hungary,  Croatia,  Slavonia,  Eouniaiiia 
and  the  Island  of  Cos,  where  they  are  remarkable  for  their  extreme  variability. 
Neiimayr  has  described  a  number  of  mutation  series  from  this  horizon,  wliich  begin 
with  smooth  Vivipara  species,  and  terminate  with  angular  Tulotoma-like  forms. 


Fig.  951. 


A,  B,  Vivipara  hrusinae  Neumayr,  C,  V.  (Tulotoma)  forbesi  Neumayr. 
Pliocene  ;  Isle  of  Cos.  D,  V.  {Tulotoma)  hoerneri  Neumayr.  Pliocene :  Novska, 
Slavonia. 


Family  10.     Hydrobiidae  Fischer  {Ämnicolidae  Tryon). 

Shell  turbinate  to  turreted,  small,  usually  thin,  and  either  smooth,  longitudinally 
ribbed  or  spirally  keeled.  Äperture  ovate ;  operculum  horny  or  calcareous,  spiral  or 
concentric.     Cretaceous  to  Eecent. 

These  are  fresh  or  brackish  water  inhabitants,  some  of  which,  however,  are  able  to 
survive  for  a  considerable  period  on  land.  It  is  difficult  to  distinguish  the  different 
genera  belonging  to  this  family  by  means  of  shell  characters  alone.  All  the  forms 
are  diminutive. 

Bithinia  Gray  (Fig.  952).  Thin-shelled,  turbinate,  with  umbilical  fissure. 
Peristome  continuous,  outer  lip  sharp.  Operculum  calcareous,  concentric.  Wealden 
to  Eecent. 


CLASR  IV 


GASTROPODA 


545 


Staliola    Brusina.     Outer    lip   thickened ;    operculum  calcareous.     Cretaceoiis   to 

Miocene. 
.1  ('  Fosmrulus  Neuinayr.      Like   tlie   last,  but  vvitli   Bpiral    ribs. 

Upper  Miocene. 
HWL  z*^  Nematura    Benson    {Stenothyra    Benson)    (Fig.    953).      Like 

Bithinia^  but  aperture  contracted.     Operculum  calcareous,  spiral. 

Tertiary  and  Recent. 


Fig.  952. 


A ,  Bithinia  tentaculata 
(Linn.).  Upper  Mionene; 
Miocic,  Dalmatia.  B, 
Operculum  of  same.  C, 
B.  gracilis  Sandb.  Fresh- 
water  Molasse ;  Ober- 
kirchberg, near  Ulm. 


Fio.  953. 

Nematura  ptipa  (Nyst). 
Oligocene ;  Hackenheim, 
near  Alzey. 


Fio.  954. 

Nystia  chastelii 
(Nyst).  Middle  Oligo- 
cene ;  Klein-Spouwen, 
Belgium. 


Fm.  955. 

Hydrohia  acuta  A. 
Braun.  Miocene ; 
Weissenau,  near 
Mayence. 


Nystia  Tourn.  {Forbesia  Nyst)  (Fig.  954).  Outer  lip  reflected ;  operculum 
calcareous,  spiral.     Tertiary  and  Recent. 

Assiminea  Leach.     Tertiary  and  Recent. 

Hydrohia  Hartm.  {Littorinella  Braun  ;  ToiLrnoueria  Brusina)  (Fig.  955).  Conical 
to  turreted,  acuminate,  smootli,  Aperture  oval ;  operculum  homy,  paucisj)iral. 
Cretaceous  to  Recent.  The  Indusia  Limestone  (Lower  Miocene)  of  Auvergne  is 
almost  exclusively  composed  of  the  shells  of  H.  duhuissoni  Bouill.  Similarly,  the 
Littorinella  Limestone  of  tlie  Mayence  Basin,  wliich  is  of  equivalent  age,  is  made 
up  of  the  Shells  of  H.  acuta  Braun.  Strata  in  the  fresh-water  limestone  of  Nördlingen 
are  charged  with  H.  trochulus  Sandb. ;  and  the  Upper  Eocene  marl  of  St.  Ouen  is 
filled  with  the  remains  of  H.  fusilla  (Prev.). 

Other  genera  and  subgenera  closely  related  to  the  foregoing  are  Bythinella  Moq.  ; 
Amnicola    Gould  ;     Belgrandia    and  ^  ^  ^ 

Lartetia    Bourguignat ;    Lappare^itia 
Berthelin. 

Pyrgula  Christofori  and  Jan. 
(Fig.  956,  Ä).  Turreted,  whorls 
spirally  keeled  or  ribbed.  Peristome 
continuous.     Tertiary  and  Recent. 

Genera    allied    to    the    last    are 

Micromelania    Brus.    (Fig.    956,    5) :         ,     „ 

.       rx     1      /-r-.  r,      Jy.  ^»    Py^gula    eugeiiiae    Neumayr. 

Mohrensternia     ötol.     (Fig.     956,     C);    Upper   Miocene;  Arpatak,  Transyl- 

Pyrgidium   Tournouer  ;    Prososthenia   SSi  (N»ima"r' Uppi?  mS"! 

Neumayr.       Tertiary.  Miocic,  Dalmatia.     C,  Mohrensternia 

T -±1      1      i,  ry-      1       /■x^•         nc^7\      m^«ta  Andfzewsky.  Congerien  Stage 

Llthoghjphus     Ziegl.      (Fig.     957).    (Miocene) ;  Inzensdorf,  near  Vienna. 

Globose  or  ovate,  with  short  spire  ; 

rather  thick  and  aolid.  Aperture  large,  obliquely  oval ;  inner  lip  thickened. 
Tertiary  and  Recent ;  Europe.  Similar  forms,  Somatogyrus  Gill,  and  Flumincola 
Stimpson,  occur  in  North  America.  There  are  other  related  genera  in  south-eastern 
Asia  and  South  America. 


Fio.  956. 


Fio.  957. 

Lithoglyphus  fusciis 
Ziegler.  Upper  Mio- 
cene ;  Malino,  West 
Slavonia. 


Family  11.     Rissoidae  Troschel. 

Shell  small,  thick,  turhinate  to  turreted,  usually  ribbed  or  spirally  striated,  rarely 
smooth.  Aperture  oval,  angular  posteriorly,  often  with  anterior  canal.  Operculum 
homy,  paucispiral.     Jura  to  Recent. 


Eissoina  d'Orb.  (Fig.  958). 
VOL.  I 


Turreted,  transversely  ribbed,  rarely  smooth  :  outer 

2  N 


546 


MOLLUSCA 


phylü!m  vi 


lip  arcuate,  generally  tliickened 


aperture  somewliat  iiotclied  or  effuse  at  tlie  base. 
Dogger  to  Recent ;  mainly 
Tertiary. 

Rissoa  Frem.  (Fig.  959). 
Turreted,  transversely  ribbed 
or  cancellated,  aperture  eutire 
below.     Jura  to  Recent. 


FiCx.  958. 
A,  Rlssoina  amoena  Zitt.  Tithon- 
ian ;   Stramberg,   Moravia.     B,   B. 
(Ifcussata  Montf.    Miocene;  Steina- 
brunn,  near  Vienna. 


Fio.  959. 

A,  Risfioa  turbinata  (Laiii.). 
Oligocene;  Weinheim,  near 
Alzey.  B,  R.  (Alvania)  mon- 
tagui  Payr,  Miocene  ;  Steina- 
brunn,  near  Vienna. 


Family  12.     Turritellidae 
Gray. 


Shell  turreted,  with  high 
acuminate  spire.  TFhorls  numerous,  iisually  spirally  rihhed  or  striated.  Aperture  oval, 
round  or  quadrangular,  sometimes  with  faint  anterior  canal.  Outer  lip  thin,  peristome 
discontinuous.      Operculum  horny,  multispiral     Marine.     Trias  to  Recent. 

Turritella  Lam.  (Figs.  960,  961).  Spire  very  high;  aperture  oval  or  rounded 
quadrilateral ;  outer  lip  thin,  excavated  behind,  and 
slightly  produced  in  front.  Trias  to  Recent ;  maximum 
in  Tertiary.  The  older  Mesozoic  species  are  usually 
small. 

961).       Like    the    last, 


Subgenera :  Mesalia  Gray  (Fig, 
but  aperture  with  shallow  canal, 
Tertiary  to  Recent. 

Protoyna  Baird 
{Proto  p.p.  Defr.). 
Aperture  oval,  an- 
teriorly  with  canal- 
like  contraction, 

which  is  surrounded 
externally  by  a  thick 
swelling.  Tertiary 
and  Recent.  P. 
cathedralis  Brgt. 

Glauconia   Gie- 
bel      (Omphalia 

Zekeli ;        Gassiope 

Coq.)    (Fig.     962). 

Thick-shelled,  coni- 

cal      or      turreted, 

narrowly      umbili- 

cate.  Whorls 

spirally  ribbed,  rarely  smooth.      Aperture    oval,  with  faint   canal 
anterior  and  median  emargination.     Abundant  in  the  Cretaceous. 


and    twisted    inner    lip. 


Fig.  960. 

A,  Turritella  turris  Bast.  (T. 
ir<'e?(raZiet.  nonLinn.).  Miocene 
Moljisse  ;  Eriningen,  near  Ulm. 
B,  T.  imhricataria  Lam.  Cal- 
caire  Grossier ;  Grignon,  near 
Paris. 


Turritella  (Mesalia) 
multisulcata  Lam. 
Eocene ;  Calcaire 
Grossier  ;  Grignon, 
near  Paris. 


Fig.  962. 

Glauconia  kefersteini 
Goldf.  Middle  Cre- 
taceous ;  Dreistätten, 
near  Wiener-Neust. 


outer  lip  with 


Family  13.     Vermiculariidae,  novum.     {Vermetidae  Adams). 

Shell  tubulär,  the  earlier  whorls  spiral,  the  later  ones  irregularly  twisted,  free  or 
attached.  Aperture  round;  operculum  horny,  sometimes  ivanting.  Carboniferous  to 
Recent. 

Some  fossil  Vermetidae  are  liable  to  be  mistaken  for  Serpulidae,  but  differ  from 
them  nevertheless  in  the  structure  of  the  shell  and  spiral  protoconcli.  The  determina- 
tion  of  the  few  Paleozoic  and  Mesozoic  forms  is  uncertain. 

Vermicularia  Lam.  {Vermetus  Daudin)  (Figs.  963,  964).  Shell  usually  attached, 
irregularly  tubulär,  internally  vitreous,  and  often  with  septa.  Carl)oniferous  (?)  to 
Recent.     Abundant  in  the  Tertiary. 


CLASS  IV 


GASTROPODA 


.47 


Subgenera  :    Thylaeodes  Guettard  (Fig.  963) ;  Petaloconchus  Lea  (Fig.  964).     Tertiary  and 
Recent. 

Siliquaria  Brug.  (Fig.  965).  Shell 
free,  coiled  in  a  loose  spiral.  Aperture 
lateral,  and  with  a  slit  whicli  continues 
as  a  fine  cleft  or  row  of  pores  tlirougli- 
out  the  entire  length  of  tlie  shell. 
Cretaceous  to  Recent. 


Fig.  963. 

Vermicularia  {Th  ylacodes)  arenaria 
Linn.  Miocene ;  Grund,  near  Vienna. 

V2. 


V.  (Petaloconchus)  intorta  Lam. 
Pliocene ;  Montespertoli,  near 
Florence.  Some  of  the  tubes  are 
fractured  i  and  show  the  internal 
lamellae. 


Fig.  965. 

Siliquaria  striata 

Desh.  Calcaire  Grossier ; 
Chaussy,  near  Paris. 


Family  14.     Oaecidae  Adams. 

Shell  small,  discoidal  in  early  stages,  later  becoming  tubulär.     TJie  decollated  yroto- 
conch  replaced  by  a  septum.     Operculum  round,  horny.     Tertiary  and 
Recent. 

Gaecum  Flem.     Abont  one  hundred  Recent  and  twenty  Tertiary 
species  are  known. 


Family  15.     Melaniidae  (Lamarck)  Gray. 

Shell  turreted  to  oval,  with  thick,  dark-coloured  epidermis.  Apex 
usually  truncated  and  corroded.  Aperture  oval,  sometimes  canali- 
culate.     Operculum  horny,  spiral.     Jura  to  Recent. 

Living  species  inhabit  fresh,  or  more  rarely  brackisli,  waters  of 
Southern  Europe  and  the  warmer  zones  of  Africa,  Asia  and  America. 

Melania  Lam.  {Thiara  Bolten)  (Fig.  966).  Shell  smooth  or 
spirally  striated,  or  with  transverse  ribs  or  nodes.  Aperture  oval, 
anteriorly  rounded.     Upper  Jura  to  Recent. 

Stomatopsis  Stäche.     Whorls  platform-like,  with   strong  trans- 
verse ribs  ;  aperture  rounded,   with  entire,  thickened  and  reflected   uim!^  ^  ^^^ 
margins.     Lowermost  Eocene  (Cosina  Beds)  ;  Istria  and  Dalmatia. 

Pyrgulifera  Meek  (Hautkenia  Munier-Chalm.)  (Fig.  967).     Shell  thick,  elongate- 
oval,  with  platform-like,  transversely  ribbed,  and  spirally  striated  whorls.     Aperture 


Fio.  966. 
Melania        eseheri 


Brongt. 


Miocene ; 
near 


548 


MOLLUSCA 


THYLUM  VI 


oval,  sometimes  with  very  faint  canal.  Upper  Cretaceous  of  Europe  and  North 
America, 

Paramelania  Sniitli.     Resembles  tlie  preceding,     Living  in  Lake  Tanganyika. 

Fascinella  Stäche ;  Goptostylus  Sandb.  ;  Faunus  Montf. ;  Hemisinus  Swainson. 
Upper  Cretaceous,  Eocene  and  Recent. 

Melanopsis  Fer.  (Figs.  968-970).     Shell  oval  to  turreted,  smooth  or  ornamented. 


Fig.  967. 

PyrguUfera  pich- 
leri  (Hoernes). 
Upper  Creta- 
ceous; Ajka, 
Hungary. 


Fig.  968. 

MeloMopsis  gdllo-pro- 
vincialisMsLth.  Upper- 
most  Cretaceous ;  Mar- 
tigues,  near  Marseilles. 


Melanopsis  mar- 
tiniana  Fer.  Mio- 
cene ;  Nussdorf, 
near  Vienna. 


Fig.  970. 

Melanopsis  {Can- 
thidomus)  acanthica 
Neumayr.  Upper 
Miocene;  Miocic, 
Dalmatia. 


Fig.  971. 

Pleurocera  stfomhi- 
formis  (Schloth). 
Wealden ;  Oster- 
wald,  Hannover. 


Upper 


Base  of  columella  trimcated  ;  aperture  with  short  canal ;   inner  lip  callous. 
Cretaceous  to  Recent.     Remarkably  abundant  in  the  Miocene  and  Pliocene. 

Pleurocera  Raf.  (Fig.   971).     Like  Melania,  but  aperture  with  faint  canal,  and 
outer  lip  sinuous.     Cretaceous  to  Recent ;  occurs  only  in  North  America. 

Goniohasis  Lea ;    Änculosa   Say  {Leptoxis  Raf.) ;  Ptychostylus   Sandb.     Wealden. 
The  first  two  occur  Tertiary  and  Recent  in  North  America  only. 


Family  16.     Nerineidae  Zittel. 
Shell  turreted,  pyramidal  or  ovate,  perforate  or  imperforate.     Aperture  anteriorly 

A  B  C  D 


Fio.  97: 


Trochalia  consohrina  Zitt. 
Tithonian ;  Stramberg,  Mor- 
avia.     Longitudinal  section. 


Fig.  973. 

A,  Nerinea  defrancei  d'Orb.  Coral-Rag ;  Coulanges  sur  Yonne.  B,  N. 
(Hkitata  d'Orb.  Coral-Rag ;  Oyonnax,  Ain.  C-E,  N.  hoheneqgrri  Peters. 
Tithonian  ;  Stramberg,  Moravia.     (',  2/,,.     j),  Vi-     E,  Longitudinal  section. 


CLASS  IV 


GASTROPODA 


.49 


loith  short  canal  or  shallow  notch.  Golumella  and  Ups  with  strong  folds,  contimious 
throughoid  the  eniire  length  of  the  spire.  Outer  lip  thin,  posteriorly  luith  ßssure-like 
incision,  which  leaves  a  small  slit-hand  immediately  heneath  the  suture  on  all  the  whorls. 
Marine.     Trias  to  Cretaceous. 

Aptyxiella  Fisch.  (Äptyxis  Zittel,  non  Troschel).  Turreted,  very  slender,  im- 
perforate.  Aperture  qiiadrangular ;  inner  and  oiiter  Ups  witliout  folds ;  columella 
somewhat  thickened.     Trias  to  Upper  Jura. 

Trochalia  Sharpe  {Gryptoplocus  Pict.  and  Camp.)  (Fig.  972).  Turreted  to 
pyramidal,  usually  smooth  and  imperforate.  The  inner  lip  only  has  a  strong,  simple 
ibid.     Jura  and  Cretaceous. 

Nerinella  Sharpe  (Pseudonerinea  Loriol).  Turreted,  imperforate.  Outer  lip  and 
sometimes  also  the  columella  with  a  simple  fold.     Jura. 

Nerinea  Defr.  (Fig.  973).  Turreted  or  pyramidal,  usually  imperforate.  Columella 
invariably,  and  inner  and  outer  lips  generally,  with  simple  folds.  Jura  and  Cretaceous  ; 
maximum  in  the  Coral-Rag  (Upper  Jura). 

Ptygmatis  Sharpe  (Fig.  974).     Like  the  last,  except  that  the  folds  on  both  lips 
and  the  columella  are  complicated  by  second- 
ary  constrictions  and  branchings.     Jura  and 
Cretaceous. 

Itieria  Math.  (Fig.  975).  Elongate-oval, 
usually  umbilicate.  Spire  short,  sometimes 
insunken,  Body  whorl  very  large,  more  or 
less  enveloping  the  preceding.  Columella 
and  both  lips  with  folds.  Jura  and  Cre- 
taceous. 


Family   17.     Cerithiidae  Menke. 

Shell  turreted;  aperture  elongated  oval,  or 
quadrilateral,  anteriorly  with  short  canal. 
Outer  lip  often  thickened  and  reflected,  or  thin 
and  sharp.  Columella  sometimes  with  one 
or  tivo  folds.  Operculum  horny,  spiral. 
Marine  and  hrackish  water.     Trias  to  Recent. 


Fio.  974. 

Ptygmatis  pseudo- 
bruntrutana  Gem- 
mellaro.  Tithonian; 
Inwald,  Carpathia. 
Vertical  section. 


Fig.  975. 

Itieria  staszycii  Zeuschner. 
Tithonian ;  Inwald,  Car- 
pathia. 


More  than  1000  living,  and  about  500 
fossil  species  are  known,  the  latter  being  most  numerous  in  the  Eocene.     The  earliest 
forms  are  usually  of  small  size,  and  have  a  nearly  entire  peristome. 

Gerithinella  Gemm.  (Fig.  976).     Shell  turreted,  slender.     Whorls  numerous,  flat, 

ornamented  with  spiral  ribs  or  rows  of  small  nodes. 
Aperture  quadrilateral,  with  very  faint  canal. 
Jura. 

Cryptaulax  Täte  (Pseudocerithium  Cossmann). 
Small,  turreted.  Whorls  with  spiral  ribs  or  rows 
of  nodes  and  transverse  folds.  These  last  usually 
run  continuously  in  a  somewhat  oblique  direction 
from  one  whorl  to  the  next.  Aperture  oval  or 
quadrilateral,  with  scarcely  perceptible  canal. 
Trias  and  Jura. 

Ceritella    Morris  and  Lyc.   (Fig.   977).     Trias 
and  Jura.      Fibula    Piette   (Fig.   978).      Trias    to 
Cretaceous.     Pseudalaria  Huddlest. ;  Ditretus  Piette.     Jura. 

Exelissa  Piette  (Fig.  979).     Very  small,  turreted  ;  whorls  with  strong,  continuous 


Fi(!.  976. 

Cerithinella  aiinata 
Goldf.  Torulosus 
Beds  (Middle  Jura) ; 
Pretzfeld,  Franconia. 


Fig.  977. 

Ceritella  conica 
Morris  and  Lyc. 
Great  Oolite  ;  Min- 
chinhamptoii,  Eng- 
land. 


550 


MOLLUSCA 


PHYLUM  VI 


transverse  ribs  and  spiral  Striae.     Aperture  contracted,  rounded,  without  canal,  some- 
times  slightly  separated  off,  and  with  continuous  peristome.     Abundant  in  the  Jura. 
Bittium  Leacli  (Fig.  980).     Turreted,  with  granulated  spiral  ribs, 
and  numerous  transverse  costae.     Aperture  with  short,  straight  canal ; 
outer  lip  sharp.     Jura  to  Kecent.     Abundant  in  the  Tertiary. 
Triforis  Deshayes  ;  Gerithiopsis  Forbes.     Tertiary  and  Recent. 

Eustoma  Piette.  Aperture  with 
long  canal,  which  is  often  closed, 
however,  by  margins  of  the  inner 
and  outer  lip.  Inner  lip  callous 
and  strongly  dilated  ;  outer  lip 
expanded.     Jura. 

Gerithium  Brug.  (Figs.  981, 
982).  Turreted,  imperforate,  with- 
out  epidermis.  Aperture  oblong, 
ovate,  with  backwardly  curved 
canal ;  outer  lip  often  soinewhat 
reflected.  Columella  concave,  fre- 
quently  with  one  or  two  folds. 
Certain  Tertiary  species  attain  a  length  of  half  a  metre  (C.  giganteum).  Jura  to 
Recent ;  maxinium  in  Eocene. 

Subgenera  :  Vicarya  d'Arch.  ;  Glava  Martyn  (Fig.  982)  ;  Bellardia  Mayer,  etc. 

Potamides  Brongt.  (Figs.  983,  984).  Turreted,  with  epidermis;  aperture  with 
emargination  or  faint  canal.  Inhabits  only  brackish  water  or 
estuaries.     Cretaceous  to  Recent. 


Fig.  978. 

Fibula  undulosa 
Piette.  Bathon- 
ian ;  Bparcy, 
Aisne. 


Fig.  979. 

Exelissa  strangu- 
lata  (d'Arch.). 
Bathonian  ; 
Eparcy,  Aisne. 


Fig.  980. 

Bittium  plicatum 
Brug.  Oligocene; 
Ormoy,  near  Etampes, 
France, 


Fig.  981. 

Gerithium  serratum 
Brug.  Calcaire  Gros- 
sier ;  Damery,  near 
Epernay. 


Fig.  982. 

Cerithium  {Glava) 
nudum  Lam.  Eocene ; 
Chaumont,  near  Paris. 


Potamides  (Tympano- 
tomus)  margaritaceum 
Brocchi.  Oligocene  ; 

Hackenheim,  near  Alzey. 


Subgenera :   Tympanotomus  Adaras  (Fig.  983)  ;  Pyrazus,  Telescapium  Montf. 
Swains. ;  Lampania  (Fig.  984)  and  Pyrenella  Gray  ;  Sandbergeria  Bosq. 


Fig.  984. 
Potamides  (Lampania) 
pleurotomides  Desh. 
Middle  Meeressand ; 
Mortetbntaine,  8eine-et- 
Oise. 

Cerühidea 


Family  18.     Aporrhaidae  Philippi. 

Shell  fusiform,  turreted  or  conical  ovate.  Aperture  produced  anteriorly  in  a  canal. 
Outer  lip  expanded  in  a  wing-like  or  digitiform  fashion^  or  thickened.  Operculum  horny. 
Marine.     Jura  to  Recent ;  maximum  in  Jura  and  Cretaceous. 

Älaria  Morris  and  Lyc.  (Figs.  985-988).  Shell  turreted  ;  aperture  with  long  or 
Short  canal.     Outer  lip  not  overriding  the  last  whorl,  digitated  or  winged.     Spire 


CLASS  IV 


GASTROPODA 


551 


and  body  whorl  often  retaining  tiaces  of  apertures  at  earlier  stages.     Veiy  abimdant 
in  Jura  and  Cretaceons. 


Subgenera  :    Dicroloma  Gabb ;    Anchura    Conrad    (Fig.    987). 
Cretaceous.     Diempterus  Piette.     Jura. 


Jura    and 


Fig.  985, 


Alaria  myurus  Deslongch. 
Lower  Oolite ;  Bayeux,  Cal- 


FiG.  987. 


Fig. 

Alaria  armata  Morris 

and  Lyc.    Great  Oolite;  Alaria  (Anchura)  cari- 

Minchinhanipton,    Eng-  nata      Mant.        Gault ; 

land.     .  Folkestone,  England. 


Fig.  988. 

Spinigera  semicarinata 
(Goldfuss).  Callovian ; 
Montreuil  -  Bellay, 
Maine-et-Loire. 


Spinigera  d'Orb.  (Fig, 
rows  of  spines.     Jura. 

Aporrhais  Da  Costa  {Ghenopus  Phil.)  (Figs. 
989-991).  Like  Alaria,  but  niargins  of  aperture 
elongated  posteriorly  in  a  canal,  which  remains 
either  attached  to  tbe  spire,  or  extends  free  froiu 
the  sanie.  Outer  lip  expanded,  digitated  or  lobed. 
Jura  to  Recent. 


Wliorls  keeled  and  ornamented  with  two  opposite 


Subgenera  :  AUpes  Conrad  ;  ArrJioges,  Tessarolax^ 
Helicaulax  Gabb  ;  Ceratosi'phon  Gill ;  Cuphoselenus, 
Malaptera  Piette  ;  Pterocerella  Meek  ;  Dimorphosoma 
St.  Gardner  (Fig.  990)  ;  Lispodesthes  White  (Fig. 
991).     Jura  and  Cretaceous. 


Fi(i.  989. 

Aporrhais  tridaciylus  A.  Braun.  Oligo- 
cene  ;  Hackenheim,  near  Creuznacli. 


Fk;.  990, 

Aporrhais  (Dimor- 
phosoma) calcarata 
Sowb.  Upper 
Greensand ;  Black - 
down,  England. 


Fig.  991. 

Aporrhais  (Lispodesthes)  rettssi  Geinitz 
var.  viegaloptera  Reuss.  Pläner ;  Postelberg, 
Boheinia. 


Family  19.     Strombidae  d'Orbigny. 

Shell  conical,  turreted  or  fitsiform,  with  acuminate  spire.  Aperture  canaliculate ; 
outer  lip  often  expanded,  anteriorly  with  an  emargination.  Operculum  horny.  Jura 
to  Recent. 

Although  the  shells  of  this  family  are  excessively  variable,  the  soft  parts  of  the 
animals  exhibit  great  uniformity  of  structure. 


552 


MOLLUSCA 


PHYLUM  VI 


Harpagodes  Gill   (Fig.  992).     Sj^ire  sliort,  body  wliorl  very  large.      Canal  long, 
reflected.       Outer  niargin  produced  in  a  nuniber  of  tubulär  spinous   processes,  the 
posteriormost  of  wliicli  rests  against  the  spire  and  extends 
nearly  to  the  apex.     Jura  and  Cretaceous. 


Fig.  992, 

Harpagodes  oceani  Brongt. 
Kimmeridgian ;  Lindner  Berg, 
near  Hannover. 


Sirombus  crassüahrum  Zitt.     Gosaii- 
Cretaceous  ;  St.  Gilgen,  Austria. 

Pterocera  Lam.  {Hepta- 
dactylus     Klein).         Spire 
sliort ;  canal  beut  sideways. 
Outer   margin   wing  -  like, 
with  tubulär  spinous  pro- 
cesses,   beneath    the    niost 
anterior  of  which  is  a  deep 
notch.     Kecent. 
Pterodonta  d'Orb.  ;   Thersitea  Goq.  ;  Pereiraea  Crosse.     Miocene. 
Stromhus  Linn.  (Oncoma  Mayer)  (Fig.  993).      Shell  ovoid,  tuberculose  or  spinöse, 
solid  ;  spire  with  several  whorls  ;  body  whorl  very  large.     Aperture 
elongate,  obliquely  truncated  and  channelled  anteriorly,  canaliculate 
posteriorly.     Outer  margin   dilated  in  wing -like   fashion,   usually 
thick,  often   produced   behind,   sinuate  and   sometimes  channelled 
in  front.      Columellar    border    simple,   enamelled.      Cretaceous    to 
Recent. 

Pugnellus  Conrad.  Cretaceous.  Struthiolaria  Lam.  Tertiary 
and  Recent. 

Seraphs  Montf.  (Terebellum  Lam.)  (Fig.  994).  Shell  elongate, 
sub-cylindrical ;  spire  short,  summit  obtuse.  Body  whorl  very 
large,  smooth  or  striated.  Aperture  longitudinal,  narrow  pos- 
teriorly, and  slightly  dilated  anteriorly ;  canal  short.  Outer 
margin  thin,  simple,  obliquely  truncated  anteriorly,  sometimes  pro- 
longed  in  the  spire  posteriorly  by  a  callosity.  Columellar  border 
smooth,  straight.     Tertiary  and  Recent. 

Rostellaria  Lam.  Spire  high,  whorls  smooth.  Aperture  pro- 
Seraiihs  sopituin  ^^^^^  anteriorly  in  a  beak-like  canal,  and  continued  posteriorly 
(Brander).  Caicaire  as  a  narrow  Channel  resting  on  the  spire.  Outer  margin  with 
near  Pari's.  '    denticulate  processes,  notched  anteriorly.     Late  Tertiary  and  Recent. 

Hippochrenes  Montf.  {Gyclomops  Gabb)  (Fig.  995).  Like  the  last, 
but  outer  margin  expanded  in  wing-like  fashion,  and  destitute  of  processes.  Upper 
Crataceous  and  Eocene. 


CLASS  IV 


GASTROPODA 


553 


Bimella   Agassiz   {Isopleura   Meek)  (Fig.   996).      Surface  cancellated.      Outer  lip 
with     tliickened     inargin,     entire     or 
creniüated.     Upper  Cretaceous  to  Re- 
cent. 

Orthaulax  Gabb.  Spire  wholly 
iiivolute  and  hidden.  Oligocene ; 
Antilles. 


Family  20. 
Oolumbellariidae 

Fischer, 


Fig.  996. 


A,  liimella  fismrella  (Lam.). 
Calcaire  Grossier ;  Damery, 
near  Epernay.  B,  lt.  hartonensis 
(Sowb.).  Calcaire  Grossier; 
Griguon,  near  Paris. 


Shell  thick,  elongated 
oval,  with  short  conical 
spire,  and  large,  spirally 
ribbed,  frequently  cancel- 
lated body  lohorl.  Äper- 
ture  narrow,  anteriorly  with  short  canal,  and  pos- 
teriorly  with  a  canal  directed  obliquely  outwar ds. 
Inner  lip  callous,  outer  lip  often  thickened,  denti- 
culated  or  somewhat  reflected  outwardly.  Jura  and 
Cretaceous. 


HijipoiJiKiif^  iii}ii(hisoni  Dc^h.     Calcaire 
Grossier  ;  Damery,  neai  Epernay. 


Fi(!.  997. 

^  ,      ^  „     .           ,  Fig.  998.                        Fig.  999. 

Columbellaria  coral- 

lina       (Quenst.).  Zittclia  crasslsaima        Fetersia        costata 

Ooral-Rag;      Nat-  (Zitt.).      Tithonian;  Gemm.     Tithonian ; 

theim.  Stramberg.  Palermo. 


Columbellaria  Rolle  (Fig.  997).  Surface  covered  with  nuraerous  spiral  ribs, 
sometimes  cancellated.  Aperture  long  and  narrow,  broadening  somewhat  anteriorly. 
Outer  lip  denticulated  internally,  not  thickened,  somewhat  reflected.  Anterior  and 
posterior  canals  short.      Upper  Jura. 

Zittelia  Gemm.  (Fig.  998).     Like  the  last,  but  aperture  very  narrow  or  cleft-like. 
Outer  lip  much  thickened  in  the  middle.     Tithonian. 

Golumbellina   d'Orb.      Cretaceous.      Petersia   Gemm.    (Fig.    999). 
Tithonian. 

Family  21.     Oypraeidae  Gray.     Cowries. 

Shell  ovate,  convolute.  Spire  short,  nearly  or  completely  covered.  in 
the  adult  by  the  very  large  body  ivhorl.  Aperture  of  equal  length  ivith 
the  shell,  narroio,  anteriorly  and  posteriorly  produced  in  a  usually  short 
canal.  Outer  lip  inflected.  Operculum  wanting.  Upper  Jura  to 
Recent. 

Recent    Cypraeidae    of    which    about    210    species    are    known, 
inhabit  principally  the  warmer  seas.      They  are  often  remarkable  for 
their  beautiful  coloration,  and  sometimes  attain  considerable  size.     Jurassic  species  are 
sparse  ;  Tertiary  ones  rather  more  abundant. 

Cypraea    Linn.    (Fig.    1000).      Ovoid,   ventricose,    enamelled,    smooth,    lirate    or 


I  !iprn,,f     Silin, r,s 

A.  Jirauii.  Uligc 
cene ;  Weinliein 
near  Alzey. 


554 


MOLLUSCA 


PHYLUM  VI 


tuberculate ;  spire   exposed   or   enveloped.      Aperture   narrow,    exteiiding   the   whole 
length  of  the  shell,  and  canaliciilate  at  each  extremity.      Inner  lip  and  the  inroUed 

oiiter    lip    generally   crennlate.      Jura    ((7.    titonica 
Stefan i)  to  Kecent. 

Trivia  Gray  (Fig.  1001).  Like  the  preceding, 
but  smaller,  and  sculptured  with  raised  transverse 
riblets.  Anterior  Channel  not  prolonged,  wide  and 
slightly  reverted.     Tertiary  and  Eecent. 

Erato  Kisso  (Fig.  1002).     Sniall,  ovoid  or  pyri- 
form,  with  short  conical  si)ire.     Aperture  narrow. 
Inner   lip   smooth,   except   for   anterior   columellar 
Canal  notch-like,  broad.     Cretaceous  to  Recent. 


^ 


Fig.  1001. 

Trivia  affinis  (Duj.), 
Miocene ;  Pont 
levoy,  Touraine. 


Fig.  1002. 

Erato  laevis  Don. 
Miocene ;  Nieder- 
leis,  Austria. 


folds  ;  outer  lip  denticulate. 


Family  22.     Ovulidae  Fleming. 

Like   the    Gypraeidae^    except  that   the  spire   is   convolute   instead   of  produced   and 
covered,  and  the  marginal  teeth 
of   the   radula    are    peculiarly 
modified.    Tertiary  and  Recent. 

Ovula  Brug.  Shell  ovate 
or  fusiform,  the  spire  completely 
enveloped.  Aperture  produced 
anteriorly  and  posteriorly  as  a 
canal.  Inner  lip  smooth  ;  the 
outer  reflected,  smooth  or 
denticulated.  Tertiary  and 
Recent, 

Gisortia  Jousseaume  (Fig. 
1003).  Large,  thick  -  shelled, 
ovate,  with  short  convolute 
spire.  Surface  typically  keeled 
or  coarsely  tuberculate.  Body 
whorl    with    a    blunt    ridge ; 

aperture    anteriorly  and    posteriorly   with    a   short    canal. 
gigantea  (Goldf.). 

Pedicularia  Swainson.      Sessile  on  corals.     Miocene  to  Recent. 


Fig.  1003. 

Gisortia  tuberculosa  Duclos.     Lower  Eocene  (Londinion) ; 
Ciiise  Lamotlie. 


Eocene.      G.  (Strornbus) 


Family  23.     Cassididae  Adams. 

Shell  thick,  inßated,  glohularly  ovate,  sometimes  varicose ;  spire  short,  hody   whorl 

very  large.  Aperture  narrow,  elongate,  anteriorly 
with  short  canal.  Inner  lip  resting  on  an  exten- 
sive callus,  sometimes  granulated  or  wrinkled. 
Outer  lip  more  or  less  thickened.  Operculum  horny, 
with  marginal  nucleus.  Marine.  Upper  Creta- 
ceous to  Recent. 

Galeodea  Link  {Morio  Montf.  ;  Gassidaria 
Lam.)  (Fig.  1004).  Shell  ventricose,  not  varicose. 
Canal  long,  twisted,  reverted  or  bent  sidewise. 
Inner  lip  greatly  expanded,  outer  lip  reflected, 
often  crenulate.  Columellar  border  jDÜcate. 
Upper  Cretaceous  to  Recent ;  maximum  in 
Eocene. 


Fig.  1004. 
Galeodea     carinata 
Lam.      Calcaire  Gros- 
sier ;     Grignon,     near 
Paris. 


Fig.  100.- 


Galeodea  (Sconsia) 
amhigua  (Solander). 
Oligocene  ;  Lattorf, 
near  Bernburg. 


CLÄSS  IV 


GASTROPODA 


555 


Subgenus  :  Sconsia  Gray  (Fig.  1005).     Last  wliorl  with  varix  ;  canal  sliort  and  straight. 
Upper  Cretaceous  to  Recent. 

Gassis  Lam.  (Fig.  1006).  Shell  ovoid,  ventricose,  having 
irregulär  varices.  Spire  sliort,  apertiire  elongate.  Oiiter 
lip  thickened,  refiected,  nsually  denticiüate  in  the  iiiterior. 
Inner  lip  callous,  expanded,  denticulate,  wrinkled  or  granu- 
late.  Canal  very  sliort,  broad,  sharply  recurved,  directed 
upward  posteriorly.     Tertiary  and  Recent. 


Fig.  1006. 

Cassis  sahuron  Lam.    Miocene ; 
Gainfahrn,  near  Vienna. 


Cretaceous    to 


Family  24.     Doliidae  Adams. 

Shell   thin,   inflated.     Spire   very   short,  hody   whorl  very 
large,  longüudinally  ribhed   or   cancellated.      Apertur e  wide, 
oval ;  canal  straight  or  curved.     Oper- 
culum  ahsent.     Cretaceous  to  Recent. 

Tonna   Brünnicli  {Bolium  Lam.). 
Spirally  ribbed.      Outer   lip  notched 
internally ;    canal    short,    obliquely    directed. 
Recent. 

Pyrula  Lam.  {Ficula  Swainson)  (Fig.  1007).  Spirally 
ribbed,  grooved  or  cancellated.  Aperture  very  wide  ;  outer  lip 
sharp  ;  canal  long,  broad,  straight.  Lower  Cretaceous  to 
Recent ;  maximum  in  Tertiary. 

Family  25.     Nyctilochidae  Dali. 

Fig.  1007.  Shell     thicJc,    ovate    to     fusiform,     with     epidermis.      Spire 

Pyrula  reticuiata  (Lam.).  moderately  high,  lühorls  varicose,  aperture  ivith  thickened  outer 
Vienna,  '  '  ^  ^Wi  ^^^  open,  straight  or  slightly  hent  canal.     Operculum  horny, 

with  marginal  nucleus.     Cretaceous  to  Recent. 

Nyctilochus  Gistel  {Tritonium  Link ; 
Triton,  Lotorium  Montf.).  Spire  elon- 
gated.  The  varices  do  not  run  con- 
tinuously  over  more  than  a  few  whorls. 
Columella  and  inner  lip  callous  or 
granulated.  Outer  lip  thickened  inter- 
nally and  notched.  Cretaceous  to 
Recent ;  abundant  in  the  Tertiary. 

Eugyrina  Dali  (Fig.  1008).  Oligo- 
cene  to  Recent. 

Distortrix  Link  {Persona  Montf.). 
Tertiary  and  Recent. 

Bursa  Bolten  {Ranella  Lam.)  (Fig. 
1009).  Like  Nyctilochus,  but  with  two 
opposite  varices,  whicli  are  continuous 
over  all  the  whorls.  Tertiary  and 
Recent. 


Fig.  1008. 

Eugyrina  flandrica  de,  IUiih 

Kon.     Oligocene ;  Wein-  Brocclii. 

heim,  near  Alzey.  Vienna. 


Fig.  1009. 


(Aspa)      marijin'ita 
Miocene ;  Grund,  near 


Superfamily  4.     RACHIGLOSSA  Gray. 

Radida  reduced  to  three  teeth  or  to  one  tooth  in  a  transverse  series. 

These  are  carnivorous  marine  fornis,  which  have  their  Initiation  in  the  Mesozoic, 
become  somewhat  numerous  in  the  Cretaceous,  and  form  an  important  element  of  the 
Tertiary  and  Recent  faunas. 


556 


MOLLUSCA  ■  PHYLUM  VI 

Family  1.     Columbellidae  Tioscliel. 

Shell  small,  ovate  to  fusiform,  covered  with  epidermis,  im2)erforate.  Äperture  narrow, 
canal  short.  Outer  Up  denticulated  internally,  thickened  in  the  middle. 
Tertiary  and  Eecent. 

The  typical  genus,  Golumhella  Lamarck  (Fig.  1010),  attains  its 
niaximum  distribution  in  the  Tertiary  and  Eecent  seas.  It  is  divided 
into  a  number  of  subgenera. 


Fig.  1010. 

Columbella  curia 
Duj.       Miocene ; 


Family  2.     Buccinidae  Troschel. 


Lapugy,  Transyl 
i^ania. 


Shell  elongate-oval,  covered  with  epidermis.  Äperture  ivide,  with 
short  canal.  Outer  Up  sharp  or  thickened.  Operculum  horny.  Cretaceons 
to  Recent. 

Buccinum  Linn,  Infiated,  smooth  or  transversely  ribbed.  Spire  moderately 
high  ;  äperture  wide  ;  canal  short,  wide,  open.  Outer  lip  sharp  and  thin,  inner  lip 
somewhat  callous.  Distributed  principally  in  waters  of  the  niore 
northerly  zones  {B.  undatum  Linn.).  Fossil  in  the  Crag  and 
Pleistocene. 

Cominella  Gray  (Fig.  1011).  Usually  spirally  ribbed.  The  last 
whorl  somewhat  depressed  beneath  the  suture,  so  that  the  äperture 
forms  a  small  groove  posteriorly.  Outer  lip  sharp  or  crenate  inter- 
nally.    Upper  Cretaceous  to  Recent. 

Pseudoliva   Swains,  (Fig.   1012).     Like  the   last,  but  outer  lip 

with    a    small    basal    tooth  or    notch  which     ^     .    „ 

,  1       1      T         1       T       Commella  casstaaria 

corresponds  to  a  groove  on  the  body  whorl.   a.  Braun,  oiigocene; 
Upper  Cretaceous  to  Recent. 

Bivona    {Pisanella    v. 


Fig.  1011. 


Hackenheim, 

Alzey. 


Koenen  ; 
Taurinia  Bellardi).  Elon- 
gate-ovoid,  spire  moder- 
ately high.  Whorls 
smooth  or  spirally 
striated.  Outer  margin 
thickened,  notched  inter- 
nally. Tertiary  and  Re- 
cent. 

Gantharus         Bolten 
(Pollia  Gray  ;  Tritonidea 

Fig.  1012.  Fig.  1013.  Fig.  1014.  SwaillS.)       (Fig.        1013). 

Pseudoliva   zitteli  Petliö.  Gantharus  sublavatus  Ehurna       caronis  Oval,  inilated  ;    spire  and 

Upper  Cretaceous ;  Fniska  (Bast.).  Miocene;  Enz-  (Brongt.).     Eocene ;  aperture    of    about    equal 

Gora,  Hungary.  esfeld,  neartVienna.  Ronca,  nearVicenza.  ,         ^t                 p                    ■,^ 

length ;  suriace  usually 
spirally  ribbed  and  transversely  folded.  Columella  often  with  weak  transverse  folds  ; 
outer  margin  thickened,  crenate  internally.  Aperture  posteriorly  with  a  short  canal. 
Tertiary  and  Recent. 

Phos  Montf.  Shell  elongate,  bucciniform,  turriculate ;  spire  sharp,  elevated, 
whorls  ornameiited  with  prominent  longitudinal  costae,  and  less  salient  spiral  threads 
and  sulci,  often  varicose.  Aperture  oblong ;  outer  margin  lirate  within.  Columella 
excavated,  plicate  in  front ;  canal  short,  slightly  twisted.     Tertiary  and  Recent. 

Ehurna  Lam.  {Dipsaccus  Klein)  (Fig.  1014).  Resembling  Nassa,  but  smooth, 
perforate,  and  with  deeply  incised  sutures  ;  outer  margin  sharp.      Tertiary  and  Recent. 

Nassa  Lam.  {Älectrion  Montf.)  (Fig.  1015).  Ovate,  inflated.  Aperture  with  short, 
reverted  canal ;  inner  lip  callous,  expanded ;  outer  margin  usually  crenate  internally. 


CLASS  IV 


GASTROPODA 


Sparse  in  Upper  Cretaceous  and  Eocene,  abundant  in  Miocene  and  Pliocene  ;   living 
species  exceediiig  200  in  number,  and  distiibuted  in  numerous  suljgenera.  . 

Gyclonassa  Agassiz  ;  Gyllene  Gray  ;  Truncaria  Adams ;  Buccinopsis  Conrad. 
Tertiary  and  Recent. 

Ghrysodomus  Swains.  {Neptunea  p.p.  Bolten).  Elongate-ovoid,  inflated,  sometimes 
sinistral,  witb  rather  short  and  moderately  bent  canal.  Cretaceous  to  Recent.  C. 
contrarius  Lam.     Crag. 

Siphonalia,  Zemira,  Metula  Adams ;  Euthria  Gray ;  Hemifusus  Swainson  (Fig. 
1016).  Tertiary  and  Recent.  Mitraefusus  and  Genea  Bellardi.  Neocene. 
Melongena  Schum.  {Pyrula 
Lam.  p.p.;  Myristica  Swains.)  (Fig. 
1017).  Pyritbrm,  inflated,  with 
short  spire.  Body  wliorl  large, 
longitudinally  striated  and  beset 
with  nodes  or  rows  of  spines.    Inner 


Fig.  1015. 

Nassa  clathrata  Brocchi, 
Pliocene ;  Larniano,  Tus 
eany. 


Fig.  1016. 
Hemifusus  subcarinrüus 
(Lam.).      Eocene  (Sables 
moyens) ;    Senlis,    Seine- 
et-Oise. 


Fig.  1017. 
Melongena  cornuta  Agassiz,     Miocene  ;  Bordeaux. 


Fio.  1019. 

Strepsidura  ficulnea 
(Lam.).  CalcaireGrossier; 
Damery,  near  Epernay. 


lip  smooth;  aperture  gradually  becoming  merged  into  the  short  and  wide  canal. 
Tertiary  and  Recent. 

Bu^con  Bolten  {Fulgur  Montfort).     Tertiary  and  Recent. 

Tudicla  Bolten  (Fig.  1018).  Resembles  FuUjur  but  has  a  straight  and  very  long 
canal  ;  inner  lip  with  a  fold.     Cretaceous  to  Recent. 

Strepsidura  Swains.  (Fig.  1019).  Spire  short ;  body  whorl  inflated,  tmnsversely 
ribbed  :  canal  curved.     Eocene  and  Miocene. 


Family  3.     Muricidae  Tryon. 
Shell  thick     Spire  moderately  high ;  whorls  with  transverse  swellings,  ribs  or  folia, 
and  frequently    spinöse. 


Aperture  rounded  or  oval;    canal  more   or   less   elongateJ^ 


558 


MOLLUSCA 


PHYLUM   VI 


ivholly  or  partially  covered  hy  margins  of  the  inner  and  outer  Ups.     Operculum  horny. 
Cretaceous  to  Eeceiit. 

Murex  Linn.  (Figs.  1020-1022).     Shell  roimded,  spire  prominent.     Surface  with  at 
least  three,  often  more  than  tliree  varices  or  transverse  rows  of  spines  or  nodes  on  each 

whorl.  Apertiire  ovate  ;  inner  lip  smooth,  outer  lip 
thickened.  Canal  much  prolonged,  partially  closed, 
usually  spinöse.     Cretaceons  to  Kecent. 


Fig.  1020. 

Murex  (Phyllonotus)  sedgwicki  Micht. 
Miocene  ;  Gainfahrn,  near  Vienna. 


Fig.  1021 
Murex  spinicosta  Bronn, 


Fig.  1022. 

Murex       (Purpura) 
tricarinatus  Lam.  Eo- 


FiG.  1023. 

Typhis      tubifer 
Montf.       Calcaire 


Miocene  ; 
Vienna. 


Baden      near    cene ;    Damery,    near    Grossier;  Grignon, 


Epernay. 


near  Paris. 


Subgenera  :  Haustellum  Klein  ;  Rhinacantha  Adams  ;  Chicoreus,  Phyllonotus  (Fig.  1020) 
Montfort ;  Purpura  Martyn  {Pteronotus  Swainson)  (Fig.  1022)  ;  Tritonalia  Fleming  {Oeinehra 
Leacli),  etc. 

Typhis  Montf.  (Fig.   1023).     Like  Murex,  but  with  hollow  spines.     Canal  short, 

completely  closed.     Upper  Cretaceous  to  Ee- 
cent. 

Trophon  Montf.  Spire  high.  Longitu- 
dinal  ribs  replaced  by  thin  lamellae.  Canal 
open,  somewhat  curved.    Tertiary  and  Eecent. 

Family  4.     Thaisidae  Dali. 

Shell  thick,  usually  ovoid ;  spire  short, 
hody  whorl  large.  Aperture  ivide,  inner  lip 
and  columella  more  or  less  flattened ;  canal 
short.  Operculum  horny.  Cretaceous  to  Ee- 
cent. 

Fir   1024  ^^    ' 

Fig.  1025.  Thais  Bolten  (Purpura  Brug.)  (Fig.  1024). 

Raijana  laxecarinata  Micht.    Imperforate ;    body    whorl    with    transverse 
OUgocene;    Santa    Giustina,    ^ibs  or  nodes.     Aperture  oval,  columella  flat- 
tened, smooth.     Tertiary  and  Eecent. 
Bapana  Schum.  (Fig.  1025).     Like  the  preceding,  but  perforate.     Inner  lip  callous, 
expanded.     Cretaceous  to  Eecent. 

Lysis  Gabb  ;  Stenomphalus  Sandberger.      Cretaceous  and  Tertiary. 
Bistrum  Montf.  {Ricinula   Lam.) ;    Äcanthina   Fischer  de  Waldheim   {Monoceros 
Lam.) ;  Goncholepas  Lam. ;  Gymia  Mörch,  etc.     Tertiary  and  Eecent. 


Thais  exilis 
Partsch.  Mio- 
cene ;  Möllers- 
dorf, near  Vienna. 


ÖASTROPODA 


559 


Family  5.     Fusidae  Tryon. 

Shell  turreted,  fusiform  or  ovoid,  generally  loithout  varices.  Canal  more  or  less 
elongated.  Inner  lip  smooth,  or  with  weak  columellar  folds  ;  outer  margin  thin.  Oper- 
culum  horny.     Jura  to  Recent. 

These  sliells  are  sparse  in  tlie  Upper  Jura  and  Cretaceous,  but  abundant  in  tlie 


Fig.  1026. 

Fususlongirostris  Fio.  1027.                                      Fio.  1028. 

Brocchi.  Miocene ;  Clavella  longaevus  ham.        Sycumbulbiformis (Lanu),  C&l-                      Fig.  1029. 

Baden,         near  Eocene  ;    Damery,    near    caire  Grossier ;    Grignon,   near      Fasdolaria  tarbelliana  Grat. 

Vieniia.  Epernay.                                Paris.                                                Miocene ;  Grund,  near  Vienna. 

Tertiary  and  Recent.     The  animal  difFers  somewhat  from  that  of  the  Buccinidae  and 
Muricidae. 

Fusus  Lam.  {Fusiniis  Raf. ;  Colus  Humph.)  (Fig.  1026).  Shell  narrow,  elongate  ; 
spire  acuminate.  Aperture  ovate ;  canal  very  long,  straight,  open.  Outer  niargin 
thin,  sometimes  crenulate,  and  often  striate  within ;  columella  smooth.  Rare  in 
Upper  Jura  and  Cretaceous,  very  profuse  in  Tertiary  and  Recent. 

Glavella  Svvains.  (Cyrtulus  Hinds)  (Fig.   1027).     Thick-shelled,  smooth  or  with 
fine  Spiral  Striae.   Body  wliorl  suddenly  contracted  anteriorly.   Canal 
very  long,  straight.  Common  in  Eocene ;  rare  in  Neocene  and  Recent. 

Sycum  Bayle  {Leiostoma  Swains.)  (Fig.  1028).  Spire  short ; 
body  wliorl  inflated,  smooth,  somewhat  flattened  below  the  suture. 
Inner  lip  smooth  ;  canal  straight.  Common  in  the  Eocene ;  rare 
in  Miocene. 

Fasdolaria  Lam.  (Fig.  1029).  Like  Fusus,  but  distinguished 
in  general  by  having  a  sliorter  spire,  more  inflated  body  whorl,  a 
wider  and  more  sinuous  or  flexuous  canal,  and  in  that  the  anterior 
portion  of  the  columella  has  two  or  three  oblique  plications. 
Cretaceous  to  Recent.  Fio.  loso. 

Latirus  Montf.  (Fig.  1030).  Shell  fusiform,  turreted  ;  spire  Latirus  craticulatus 
Costa te.     Aperture  oblong,  outer  margiu  relatively  thin,  crenulate;   Lapngy.Transyivania.' 


560 


MOLLUSCA 


PHYLÜM  VI 


columellar  border  sliglitly  twisted,  witli  two  or  tliree  small  oblique  plaits  anteriorly  ; 
sometimes  umbilicate.      Cretaceous  to  Receiit. 

Pisanella  v.  Koenen.  Oligocene.  Peristernia  Möreli ;  Leucozonia  Gray.  Tertiary 
and  Eecent. 

Family  6.     Vasidae  Adams.     {Turhinellidae  auct.). 

Shell  similar  to  those  of  the  preceding  family,  but  with  strong,  horizontal  columellar 
folds.     Tertiary  and  Recent. 

Xancus  Bolt.  {Tmhinella  Lam. ;  Mazza  Adams  ;  Mazzalina  Conrad).  Tliick- 
shelled,  ovate  - conical,  smooth ;  spire  sliort  and  blunt,  body  wliorl  large ;  canal 
straiglit,  elongated.     Eocene  to  Recent. 

Vasum  Link  {Gynodonta  Schum.).  Shell  lieavy,  strongly  scnlptured,  often  spinöse, 
witli  short  canal.     Tertiary  and  Recent, 


Family  7.     Volutidae  Gray. 

Shell  thicJc,  ovate  to  fusiform,  dull  or  lustrous.  Spire  short  or  long,  hody  whorl  large. 
Aperture  elongated,  with  a  short  canal  or  notch ;  inner  lip  with  columellar  folds.  Oper- 
culum  usually  ahsent     Cretaceous  to  Recent. 

This  family,  as  liere  defined,  contains  genera  distributed  by  malacologists  amongst 

several  families  —  Marginellidae,  Mitridae  and 
Volutidae — all  of  whicli  are  cliaracterised  by  tlie 
strong  development  of  columellar  folds;  but  it  is 
likely  tliat  this  structure  originated  independently 
in  several  phyla  at  intervals  remote  from  one 
another.  The  Initiation  of  well-marked  genera 
with  Volutoid  plaits  occurred  in  the  Cretaceous. 
Subsequently  their  number  increased,  and  a  great 
many  generic  types  became  dift'erentiated.  The 
phylogeny  of  Tertiary  and  Recent  forms  has  been 
ably  worked  out  by  DalL^ 

Marginella  Lam.  (Fig.  1031).  Shell  oval  or 
oblong,  smooth,  glistening.  Spire  short ;  aperture 
narrow,  slightly  canaliculate  anteriorly.'  Columella 
with  three  or  four  oblique  folds  of  about  equal 
size ;  outer  margin  frequently  thickened  and  dentate. 
Tertiary  and  Recent. 

Mitra  Lam.  (Fig.  1032),  Fusiform  to  elongate- 
oval,  solid  ;  spire  high,  acuminate  ;  aperture  narrow, 
channelled  anteriorly.  Columella  with  numerous 
oblique  folds,  the  posterior  plaits 

being  often  the  strongest.     Outer  margin  commonly  thickened,  and 

smooth  internally.     Abundant  in  the  Tertiary  and  Recent. 

Turricula  Adams.    Like  the  last,  but  shell  transversely  ribbed. 

Cretaceous  to  Recent, 

Strigatella  Swains.  (Fig.  1033) ;  Gylindromitra  Fischer  {Cylindra 

Schum.) ;  Imhricaria  Schum, ;   Volutomitra  Gray  ;  Perplicaria  Dali, 

Tertiary  and  Recent, 

Lyria   Gray   (Fig,   1034).     Elongate  -  oval,    transversely  ribbed. 

Aperture  narrow.     Columella  anteriorly  with  two  much  compressed 


Fig.  1031. 

Marginella  crassula 
Desh.  Calcaire  Gros- 
sier;  Chaumont,  near 
Paris.     2/j. 


Fig.  1032. 

Mitra  fusiforniis 
Brocchi.  Plio- 

cene ;  Rhodes. 


1  Bull.    Museum    Comp.    Zoology,   vol.    xviii.,    1889  ;    Proc.    U.S.    Nat. 
Museum,  vol.  xii.,  1890,  Trans.  Wagner  Free  lust.  Sei.  Pliilad.,  vol.  iii,,  1890. 


Strigatella  lahratula 
(Lam.).  Eocene; 
Grignon,  near  Paris, 


CLASS  IV 


OASTUOPODA 


561 


and  veiy  large  i)licatio]is,  ]»eliiiid  (above)  wliicli  are  imintTou.s  weaker  oiics.  Outcr 
iiiargiii  tliickeiied.      Tertia ry  and  Recent. 

Ämpulla  Bolten  {Halia  Risso  ;  Priamus  Beck).  No  columellar  folds.  Pliocene  and 
Recent. 

VohUilühes  Swains.  (Figs.  1035-36).  Shell  fvisiform,  spire  elongate-conical;  proto- 
concli  small,  rising  to  a  more  or  less  acute  apex.  Whorls  costate,  typically  spinöse. 
Aperture  anteriorly  with  short  broad  canal ;  columellar  folds  variable,  several  in 
number,  tliose  toward  the  anterior  being  generally  the  niost  pronounced.  Abundant 
in  the  Cretaceous,  Eocene  and  Oligocene. 

Allied  genera  :  Gosavia  Stol.;  Leioderma  and  Rostellites  Conrad  ;  Liopeplum  Dali ; 
Volutoderma  (Fig.  103V)  and  Volutomorpha  Gabb.     Cretaceous. 

Äthleta  Conrad.      Spire   short,   body   whorl   inflated,  posteriorly  with   a   row   of 


Fig.  1034. 

Lyria  modesta 
A.Braun.  Oligo- 
cene ;  Weinheiin. 


Fig.  1035. 

Volutüithes  bicorona 
(Lam.).  Eocene;  Cour- 
tagnon,  near  Epernay. 


Fig.  1036. 

Volutilithes  muricinua  Jjam. 
Calcaire  Grossier ;  Damery, 
near  Epernay. 


Fig.  1037. 

Volutoderma  elon- 
(jaia  d'Orb.  Gosau- 
Cretaceous ;  St.  Gil- 
gen, Austria. 


spinous  nodes.  Inner  lip  callous,  inuch  expanded  ;  columella  anteriorly  with  three 
strong  transverse  folds,  behind  (above)  which  follow  a  few  weaker  ones.  Outer 
margin  thickened.     Miocene  and  Pliocene. 

Scaphella  Swains.  Shell  in  this  genus  is  elongate-oval  or  fusiform,  solid,  broad,  and 
with  elevated,  turbinate,  smooth  protoconch.  Spire  short,  longitudinally  plicate,  the 
folds  being  elevated  into  obtuse  tubercles  on  the  base  of  the  whorls.  Aperture  narrow, 
canaliculate  behind  and  broad  in  front ;  inner  margin  often  covered  by  a  thin  callus. 
Columella  carrying  many  plaits,  four  or  five  of  which  are  prominent,  the  remainder 
much  smaller.     Tertiary  and  Recent. 

Subgenera  :    Fulgoraria  Schuin.  ;    Scapha   Gray;   Zidona  Adams;   {Volutella  d'Orb.); 
Äuriiiia  Adams  (FoluHfusus  Conrad) ;  Caricella  Conrad ;  Adclomelon  and  Eucymha  Dali,  etc. 

Voluta  Linn.     Spire  short,  protoconch  small.    Aperture  narrow,  inner  lip  callous, 
with  numerous  transverse  folds ;  outer  margin  thickened.     Tertiary  and  Recent. 
Melo  Humphr.     {Gymbium  pars,  Bolten).     Recent. 


Family  8.     Harpidae  TroschcL 

hody  whorl  inflated^  with  sharp,  uniformly  spaced  transverse  ribs. 
Aperture  wide,  with  short  broad  canal.  Inner  lip  callous.  Operculum  absent.  Tertiary 
and  Recent. 

VOL.  I  2  0 


562 


MOLLUSCA 


PHYLÜM  VI 


The  typical  genus  Harpa  Lam.  {Silia  Mayer)  (Fig.  1038),  ranges  from  tlie  Eocene 

to  the  present  time. 

Gryptochorda  Mörcli  (?  Harpopsis  Mayer) 
(Fig.  1039).  Elongate-oval ;  spire  short, 
body  wliorl  large,  smooth,  lustrous.  Aperture 
with  Short  recurved  canal  ;  inner  lip  callous. 
Common  in  the  Eocene. 

Family  9.     Olividae    d'Orbigny. 


Fig.  1038. 

Harpa  mutica  Lam. 
CalcaireGrossier;  Grig- 
noii,  near  Paris. 


Fig.  1039. 

Gryptochorda  ström- 
boides  (Lam.).  Calcaire 
Grossier ;  Damery,  near 
Epernay. 


Shell  elongate-oval  to  suhcylindrical,  solid, 
smooth  and  glistening.  Spire  short ;  body 
whorl  very  large.  Aperture  narrow ;  outer 
lip  sharp  ;  columella  anteriorly  with  an  out- 
wardly  reflected  callus.  Canal  very  short. 
Cretaceous  to  Kecent. 


Oliva  Martyn  (Fig.  1040).     Shell  suhcylindrical ;  suture  line  marked  by  a  deep 
groove.     Columellar  callus  obliquely  folded.  .  Cre- 
taceous to  Recent. 

Olivella  Swainson.  Small,  with  acute  en- 
amelled  spire.     Tertiary  and  Recent. 

Ancilla  Lam.  (Äncillaria  Lam.)  (Fig.  1041). 
Shell  oblong,  occasionally  acuminate.  Suture 
usually  covered  over  by  a  lustrous  enamel-like 
callus.  Aperture  somewhat  broadened  anteriorly  ; 
columellar  callus  slightly  twisted.  Cretaceous  to 
Recent. 


Superfamily  5.     TOXOGLOSSA   TroscheL 


Fig.  1040. 

Oliva  clavula.  Lam. 
Miocene  ;  Dax,  near 
Bordeaux. 


Fig.  1041. 

Ancilla  ijlandi- 
formis  Lam.  Mio- 
cene ;  Steinabrunn. 


Radula  typically   with   only  two  arrow 
teeth  in  each  transverse  row,  although  occasionally  as  many  as  five  teeth  are  developed- 
Shell  similar  to  that  of  the  Rachiglossa. 

This  group  is  most  closely  allied  to  the  Rachi- 
glossa, from  which  it  probably  became  differentiated 
in  the  Cretaceous.  The  Tertiary  and  Recent  species  are 
excessively  profuse.     All  are  carnivorous  and  marine. 

Family  1.     Oancellariidae    Adams. 

Shell  oval  to  turreted.  Spire  acuminate;  hody 
whorl  inßated  ;  surface  transversely  ribhed  and  in  most 
cases  cancellated.  Aperture  with  short  canal  or  notch ; 
columella  with  several  strong  oblique  folds,  outer  lip 
grooved  internally.     Upper  Cretaceous  to  Recent. 

The  typical  genus  Gancellaria  Lam.  (Fig.  1042) 
attains  a  maximum  distribution  in  the  late  Tertiary  and  Recent. 


Fig.  1042. 

Gancellaria  can- 
cellata (Linn.).  Mio 
cene ;  Gainfahrn, 
near  Vienna. 


Family  2.     Terebridae    Adams. 

Shell  turreted,  slender,  acuminate,  with  small  body  whorl.  Aperture 
oval  or  quadrilateral ;  canal  short,  curved ;  outer  lip  sharp.  Oper- 
culum  horny.     Tertiary  and  Recent. 

Of  the  two  leading  genera,  Terebra  Lam.  (Fig.  1043)  and  Hastula  Adams,  the  first 


Fig.  1043. 

Terchra  acuminata 
Borson.  Miocene ; 
Baden,  near  Vienna. 


CLASS  IV 


GASTROPODA 


r)63 


is  characterised  by  a  line  running  parallel  witli   the  sutiue,  and  creating  a  narrow 
suture  band.     Duplicaria  Dali  lias  the  sutiire  channelled. 


Family  3.     Turritidae    Adams  (Pleuratomidae  Stoliczka). 

Shell  fusiform,  with  moderately  high  spire.  Äperture  elongated,  produced  anteriorly 
in  a  longer  or  shorter  canal.  Outer  lip  with  a  slit  or  notch  below  the  suture.  Operculum 
horny,  sometimes  ahsent.     Cretaceous  to  Recent. 

Upwards  of  700  recent  and  1000  fossil  species  have  been  described,  of  which  28 
are  Cretaceous. 

Turris  Bolten  {Pleurotoma  Lam.)  (Figs.  1044-1047).     Shell  turriciüated,  spire  long. 
A  B  c  A  B 


Fig.  1044. 
A,  Turris  notata  (Brocchi)  var.  (=r.  monilis 
Hoernes).  Miocene  ;  Baden,  near  Vienna.  B,  T.  (Sur- 
cula)  lamarcki  Bell.  Miocene  ;  Baden,  near  Vienna. 
C,  T.  (Surcula)  hclgica  Nyst.  Oligocene  ;  Weiuheim, 
near  Alzey. 

Body  whorl  of  nearly  equal  length  with  the  spire 
margin  smooth.  Outer  mar- 
gin of  the  äperture  with  a 
narrow,  deep  sinus,  situated 
at  or  some  distance  below  the 
suture.  Operculum  pointed 
ovate,  with  apical  nucleus. 
Cretaceous  to  Recent. 

Subgenera :  Surcula  (Fig. 
1044,  B,  G)  ;  Genota  Adams 
(Fig.  1045,  A)  ;  Bathytoma 
Harris  (Fig.  1046)  ;  Oligotoma, 
Rouaultia  Bellardi  ;  Crypto- 
conus  V.  Koenen  (Fig.  1045,  B) ; 
Drillia  (Fig.  1047)  ;  Bela  Gray  ; 
Lachesis  Risso,  etc. 

Ölavatula  Lamarck  (Fig.  ^^^^  j^^g^ 

1048).      Differs  from   Turris      ^.^^^^  '(Bathytoma) 
proper  in  that  the  outer  margin   cataphmcta   Brocchi. 

f     ^     ,  ,     ,,         .    .  T         Miocene ;  Baden,  near 

is  cut  by  a  shallow  triangulär   vienna. 

notch,  and  the  nucleus  of  the 

operculum  is  situated  in  the  middle  of  the  anterior  margin. 

Subgenera  :  Pseudotoma,  Glinura  Bellardi. 


Fig.  1045. 

A,  Tnrris  (Genota)  ramosa  Bast. 
Miocene ;  Grund,  Hungary.  B, 
T.  (Cryptocojius)  filosa  (L&m.).  Cal- 
caire  Grossier;  Grignon,  near  Paris. 


canal  long  and  straight ;  columeUar 


Fig.  1047. 
Turris   (Drillia) 
incrassata  Diij.    Mio- 
cene ;      Steinabmnn, 
near  Vienna.    -/j. 


Fig.  1048. 
Clavatula  asfiendata 
Lamarck,     Miocene ; 
Gnind,  Hnngary. 


Cretaceous  to  Recent 


564 


MOLLUSCA 


PHYLÜM  VI 


Borsonia  Bellardi  (Fig.  1049).  Outer  margiii  witli  a  sliallow  notch  ;  canal  long 
aud  straight ;  columella  with  one  or  two  folds ;  operculum  iinknown.  Eocene  to 
Recent. 

Mangilia  Risso  (Fig.  1050).  Shell  small,  fusiform,  imperforate  and  typically, 
with    longitudinal  costae    or  swellings.     Aperture  commonly  narrow,    with  a  short, 


Fig.  1049. 

Borsonia  delucii 
Nyst.  Lower  Oligo- 
cene  ;  Lattdorff,  near 
Bern  bürg. 


Fig.  1050. 

Mangilia  angusta 
Jan.  Plioeene  ; 
Occiano,  near  Pisa. 


Fig.  1051. 

A,  Clathurella  strom- 
hilla  Duj.  Miocene  ; 
Kienberg,  near  Vienna. 
B,  Bellardiella  reticu- 
lata  (Brocchi).  Plio- 
eene ;  Sassuola,  near 
Modena. 


Fig.  1052. 

Daphnella  (RapJd- 
toma)  vnlpecula 
Brocchi.  Plioeene  ; 
Sassuola,  near 
Modena. 


trimcated  canal ;  no  operculum  ;  sinus  near  the  suture.     Outer  margin  usually  acute, 
not  dentate  posteriorly  with  shallow  notch.     Tertiary  and  Recent. 

Allied  genera  are  the  following  :   Clathurella  Carp.  (Fig.  1051,  Ä) ;   Bellardiella 

Fischer  (Fig.  1051,  B) ;  Atoma  Bellardi;  Glypho- 
stoma  Gabb ;  Daphnella  Hinds,  with  subgenus  Raphi- 
toma  Bellardi  (Fig.  1052) ;  Eucythara  Fischer,  etc. 


Family  4.     Oonidae    Adams. 

Shell  convolute,  turhinate  or  suhcylindrical, 
generally  smooth.  Spire  short,  conical  or  ßattened. 
Aperture  long,  narrow,  anteriorly  notched.  Outer  lip 
sharp,  sometimes  with  an  anal  sinus  helow  the  suture. 
Golumella  smooth.  Operculum  horny.  Cretaceous  to 
Recent. 

This  family  is  now  enjoying  its  acme  of 
development,  having  entered  upon  its  ascendency 
during  the  Tertiary.  The  typical  genus,  Conus 
Linn.  (Fig.  1053),  is  divided  by  malacologists  into 
Ä,  Conus ponderosus  Brocchi.  Miocene;  numerous  subgenera,  connected  with  one  another 
Lapugy,  Transyivania.    B,  c.  parisiensis   by    intermediate    fomis.      It    is    initiated    in    the 

Desh.     Calcaire  Grossier;    Grignon,  near    r^     , 

Paris.  Cretaceous. 

Gonorhis  Swains.  Characterised  by  a  high 
spire,  and  a  curved,  outer  lip,  which  is  deeply  notched  posteriorly.  Eocene  and 
Oligocene. 


Fig.  1053. 


Subclass  2.     EUTHYNEURA  Spengel. 

Gastropods  in  which  the  visceral  nerve  commissures  are  not  crossed,  hut  form  a  simple 
loop ;  the  sexes  are  united  (hermaphroditic)  ;  and  the  heart  is  often  in  front  of  the  gill. 
Shell  Spiral  or  saucer-shaped,  frequently  vestigial  or  absent ;  operculum  generally  wanting. 
Radula  generally  multiserial. 


CLASS  IV  GASTROPODA 


Order  1.     OPISTHOBRANCHIA   Milne    Edwards. 

Marine,  ivater-hreathing  forms,  either  naked  or  shell-covered,  in  which  the  gills  are 
placed  behind  the  heart  and  lie  free  on  the  back  or  side ;  or  true  gills  may  be  absent, 
being  replaced  by  secondary  or  false  gills.     Heart  with  a  single  auricle. 

The  Opistliobranchiates,  imlike  the  Streptoneura  (Prosobranchiates),  send  the  blood 
into  the  heart  from  behind,  instead  of  from  the  anterior  side.  The  gills,  in  the  form 
of  a  more  or  less  branched  plume,  lie  on  the  right  side,  or  are  replaced  by  false  gills 
not  homologous  with  the  ctenidium,  arranged  either  in  two  rows  on  the  back,  or 
wreath-like  aroiind  the  anus.  The  gills  are  often  covered  by  the  mantle,  and  some- 
times  become  completely  atrophied.  The  radula  generally  resembles  that  of  the 
Pulmonates.     The  body  and  nervous  System  usually  exhibit  bilateral  symmetry. 

Three  suborders  are  recognised  in  the  recent  fauna  :  (1)  Nudihranchiata,  in  which 
a  Shell  is  absent,  except  diuing  the  larval  stage,  and  the  ctenidium  is  replaced  by  false 
gills  ;  abundantly  distributed  in  all  seas  at  present,  but  owing  to  their  perishable 
nature  are  unknown  as  fossils ;  (2)  the  Tectibranchiata,  in  which  a  mantle,  shell  and 
ctenidium  or  true  gill  is  developed ;  and  (3)  the  Pteropoda,  dating  from  the  Cambrian, 
and  from  which  the  second  suborder  is  perhaps  derived.  A  provisional  fourth  sub- 
order,  the  Gonularida,  contains  Paleozoic  forms  of  doubtful  affinities,  of  which  part 
are  probably  not  Mollusca. 

Suborder  B.    TECTIBRANCHIATA.^ 

This  group,  briefly  defined  above,  has  fossil  representatives  as  early  as  the 
Paleozoic.  During  the  Mesozoic,  a  few  genera  now  extinct  were  very  profuse.  Most 
of  the  Tertiary  species  belong  to  existing  genera. 

Family  I.     Acteonidae   d'Orbigny. 

Shell  ovate,  with  exposed  spire,  the  surface  usually  grooved  and  punctured,  sometimes 
smooth.  Apertur e  long,  rounded  below ;  columella  generally  twisted,  or  with  folds. 
Operculum  paucispiral.     Carboniferous  to  Recent. 

Solidula  Fischer  von  Waldheim  {Buccinulus  Adams ;  Dactylus  Schum.).  Ovate  or 
oblong,  compact,  solid,  with  a  short  conic  spire.  Columella  bearing  two  plications,  the 
anterior  prominent  and  bifid,  the  posterior  comparatively  inconspicuous  when  the 
Shell  is  entire  ;  between  them  the  columella  is  spirally  excavated. 
A  few  ill-defined  species  from  the  French  Eocene  and  Miocene,  one 
from  the  Australian  Pliocene,  and  numerous  Recent  tropical  species 
are  known. 

Tornatellaea    Conrad    (Fig.    1054).      Differs .  from    Solidula    and 
Acteon    in    the    more    anterior    disposition    of    the    two    columellar 
plications,  in  the  marked  depression  on  the  anterior  portion  of  the         pio.  1054. 
aperture,  and  in  the  greater  thickness  of  the  shell  near  the  outer     Tornatellaea  Hm- 
border  of  the  aperture,  which  is  frequently  crenulated.     Base  of  Jura  ^'eTef  Lattdofr; 
to  Miocene  ;  widely  distributed.     Type,  T.  bella  Conrad.     Subgenus  :  near  Bemburg. 
Triploca  Täte.     Eocene  ;  Australia. 

Acteon  Montf.  {Tornatella  Lam.  ;  Speo  Risso ;  Kanilla  Silvert.).  Oval,  spirally 
punctate-striate,  with  conic  spire.     Protoconch  not  very  prominent ;  nucleus  sinistral. 

^  Literature  (see  also  preceding  bibliographies) :  Cossmann,  M.,  Essais  de  paleoconchologie 
comparee,  i.,  1S95. —Püshn/,  IL  A.,  Monograph  of  Recent  Tectibranchiata,  in  Manual  of  Conch- 
ology,  vols.  XV.,  xvi.,  1894-95. 


566 


MOLLUSCA 


PHYLUM  VI 


Columella  thick,  witli  one  strong,  spiral,  sliglitly  oblique,  plication.      Upper  Cretaceous 

to  Recent. 

Ädelactaeon  Cossm.  {Myonia  Adams).  Sliell  witli  siiiistral  protoconcli,  tlie  latter 
not  very  large.  Wliorls  decussated  by  fine  Striae,  growtb-lines 
inconspiciious.  Columella  sliglitly  excavated,  and  carrying  a 
small  but  well-marked  plication.  Miocene  of  France  and  Ger- 
many,  and  Recent. 

■((II 


Fio.  1056. 

Actaeonina  myosotis 
Buv.  Coral-Rag;  St. 
Miliiel,  Meuse.  2/j 
(after  Buvignier). 


Fig.  1055. 

Actaeonina  do'nnoisiana 
d'Orb.  Coral-Rag;  Val- 
fln,  Ain. 


Cylindrites  acutus 
(Sowerby).  Great 
Oolite;  Minchin- 
hanipton,  England. 


Actaeonella  gigantea  Sowb.     Turonian 
Grünbach,  Lower  Austria. 


Actaeonina  d'Orb.  {Orthostoma  Desb.)  (Figs.  1055,  1056).     Shell  ovoid  to  fusiform. 
usually    smootb,    rarely    spirally    striated.      Spire  conical,    body    whorl    very    large, 
narrowing  toward  the  base.      Columella  straigbt,  witliout  folds. 
Outer  lip  sharp.     Carboniferous  to  Recent. 

Subgenera  :    jEuconactaeon,    Conactaeon    Meek. 
Lias.     Douvilleia  Bayle.    Tertiary. 


Fio.  1059. 

Actaeonella  voluta 
Goldf.  Turonian; 
Garns,  Styria. 


Fitt.  1060. 

Actaeonella     (Volvu- 


Fdr.  (Fig.  1057).  Cylindrical- 
ovoid  with  short  spire.  Columella  witli  an 
anterior  fold.     Trias  to  Cretaceous. 

Bullina  Fer.  Jura  to  Recent.  Gylindro- 
hullina  v.  Amnion,  Trias  and  Lias.  Etallonia 
Desh.  Jura  and  Tertiary.  Bullinula  Beck. 
Jura  to  Recent. 

Actaeonella  d'Orb.  (Figs.  1058  -  1060). 
Thick  -  shelled,  inflated,  smooth.  Spire  short; 
columella  thickened  anteriorly,  with  three 
Sharp  folds.     Very  profuse  in  the  Middle  and 


Hna)  laevis   Sowb.    Upper  Cretaceous ;  maximum  distribution   in 

the  Hippurite  Limestone  of  the  Alps. 

Subgenus  :  Volvulina  Stol.  (Fig.  1060).     Like  the  preceding,  but  with  insunken  spire. 
Cretaceous. 

Volvaria  Lam.      Cylindrical,  with  involute,    concealed    spire.      Surface    usually 
spirally  striated  ;  aperture  narrow  ;  columella  with  four  anterior  plications.     Eocene. 
Ovulactaeon  Dali.     Similar  in  form  to  Gypraea,  but  witliout  plications.      Recent. 


CLASS  IV 


GASTROPODA 


567 


^  Family  2.     Ringiculidae  Meek. 

Inoperculate  forms  resemhling  the  Actaeonidae  in  having  columellar  folds.  Creta- 
ceoiis  to  Receiit. 

Ginulia  Gray  (Fig.  1061).  Globose,  inflated,  spirally  grooved  or  pimctate.  Spire 
Short ;  aperture  crescentic  ;  oiiter  lip  reflected  and  thickened.  Columella  and  inner  lip 
with  numerous  transversa  folds.     Cretaceous. 

Subgenera  :  Avellana,  Ringinella  d'Orb.  ;  Eriptycha  Meek  ;  Fortisia  Bayan.     Eocene. 

Ringicula  Desh.  (Fig.  1062).  Small,  ovoid  to  globose,  thick-shelled,  with  mammil- 
lated  protoconch.      Spire  sbort ;  Iwdy  whorl  large,  usnally  smooth.     Aperture  canal- 

-1  /;  (' 


Fifi.  1061. 

A,  Cinulia  (Avellarm)  incrassata  (Mant.).  Gault ;  Perte  du 
Rhone.  B,  C.  (Ringinella)  lachryma  Mich.  Gault ;  P'olkestone, 
England.  C,  ('.  {Eriptycha)  demrtata  Zekeli.  Turonian  ;  Gosau, 
Austria. 


## 


Fl(i.  10G2. 

Ringicula  hoernesi 
Seguenza.  Miocene; 
Steinabrunn,  near 
Vienna. 


iculate  posteriorly,  excavated  anteriorly.  Columellar  border  tliick  and  callous  ;  the 
columella  arched,  and  furnished  with  from  two  to  four  plications.  Outer  margin 
usually  very  thick,  reflected,  and  occasionally  denticulated  within  Cretaceous  to 
Recent. 

Pugnns  Hedley.     Cylindrical,  with  sunkeii  spire.     Recent. 


Family  3.     Akeratidae  Pilsbry. 

Shell  oval  or  cylindrical,  thin  and  fragile,  the  spire  low  or  concealed. 
Recent. 


Tertiary  and 


Äkera  Müller  (Fig.  1063).     Thin-shelled,  flexible,  with  exposed,  truncated  spire. 
Whorls  separated  from  one  another  by  deep  sutures.     Sutures 
deep   and    prominent  ;    outer  lip  separated   from   the  spire. 
Eocene  to  Recent. 

Haminea    Leach.      Oval,  thin-shelled,  brittle ;    the  spire 
concealed.     Tertiary  and  Recent. 


Family  4.     Hydatinidae  Pilsbry. 

Glohose  or  oval,  with  exposed,  nearly  level  spire  and  tilted 
protoconch.     Jura  to  Recent. 


Fia.  1063. 

Akera  striate.lla  Lam. 
Oligocene ;  Castel  Gomberto, 
near  Vicenza. 


Hydatina    Schumacher. 
Pilsbry.     Recent. 


Jura    to    Recent.     Aplustrum  Schumacher;    Micromelo 


Family  5.     Bullariida^  Pilsbry  (emeud.). 

Shell  oval  or  suh-globose,  involute,  smooth.     Spire  sunken  and  concealed.     Aperture 
long,  rounded  anteriorly  ;  outer  lip  sharp.     Marine.    Jura  to  Recent 

Bullaria  Raf.  {Bulla  Linn.)  (Fig.  1064).     Oval,  inflated,  with  sunken  spire  and 
perforated  apex.      Aperture  rounded  posteriorly  and  anteriorly.     Jura  (?)  to  Recent. 


568 


MOLLUSCA 


PHYLÜM  VI 


Family  6.     Acteocinidae,  novum  {Tornatinidae  Fischer). 

Radula  unarmed.     Tertiary  and  Eecent. 

Äcteocina  Gray  {Tornatina  Adams)  (Fig.  1065).  Cylindrical,  witli  projecting 
spire,  and  sinistral,  tilted  protoconcli.  Columella  bearing  a  single 
fold.      Tertiary  and  Eecent. 

Retusa  Brown.      Shell  resembling  Gylichna.      Tertiary  and 
Recent. 

Volvula  Adams  (Volvulella  Newton). 
Fiisiform,  the  body  whorl  forming  a  point 
above  the  sjiire.     Eocene  to  Eecent. 


Fig.  1064. 

Bullaria  ampulla 
(Linn.).  Pliocene ;  Asti, 
Italy. 


Fig.  1065. 

Äcteocina  exerta 
(Desh.).  Oligocene ; 
Jeurres,  near  Btampes 
(after  Deshayes). 


Family  7.     Scaphandridae  Fischer. 

Spire  concealed  ;  radula  with  few  teeth  in  a 
row.     Trias  to  Eecent. 


Scaphander 


Montf.  (Fig.  1066).  Shell  sub-cylindrical,  with  epidermis,  usnally 
spirally  striated.  Body  whorl  of  enormous  capacity,  much  dilated 
anteriorly.  Columella  spiral,  leaving  a  false  nmbilicus.  Creta- 
ceous  to  Eecent. 

Atys  Montf.     Cretaceous  to  Eecent.     Diaphana  Brown.     Ter- 
tiary and  Eecent.     Smaragdinella  Adams.     Eecent. 

Gylichna  Loven  {Bullinella  Newton)  (Fig.  1067).  Small, 
cylindrical,  solid ;  spire  deeply  perforated  at 
the  summit ;  body  whorl  covering  all  the 
others.  Aperture  very  narrow,  outer  margin 
lower  than  the  axis  of  the  shell.  Columella 
thickened  anteriorly  ayd  bearing  a  small  plica- 
tion  ;  often  umbilicated.      Trias  to  Eecent. 


Fig.  1066. 


Scaphander  conic^is 
Desh.  Eocene ;  Brack- 
lesham,  England. 


Family  8.     Philinidae  Fischer. 


Fig.  1067. 
Cylielina      conoidea 


Similar  to  Scaphandridae,  hut  shell  internal,    wdnheim,  near^Tizey.' 


loosely  coiled,  punctate.     Cretaceous  to  Eecent. 
Philine  Ascan.  (Bullaea  Lam.)  (Fig.  1068).     Cretaceous  to  Eecent. 


Family  9.     Umbraculidae  Pilsbry. 

Shell  limpet-shaped,  ivith  low  suh-central  apex,  and  sharp,  thin  edges.  Tertiary  and 
Eecent. 

Umhraculum  Schum.  {Umhrella  Lam.).  Shell  orbicular,  broad, 
patelliform,  ornamented  exteriorly  with  concentric  lines  of  growth ; 
internal  surface  with  concentrically  undulating  Striae.  Eocene  to 
Eecent. 

Other  families  of  Tectibranchiata,  such  as  Aplysiidae,  Pleuro- 
hranchidae,  etc.,  are  represented  in  the  Eecent  fauna,  but  tlieir  thin, 
often  membranous  shells  have  not  been  found  fossil.  The  supposed 
Aplysias  reported  from  the  Pliocene  by  Philippi  are  flakes  from  the 
interior  of  Pelecypod  valves. 


Fig.  1068. 

Philine  excavata 
Deshayes.  Eocene. 
Calcaire  Grossier ; 
Grignon,  near  Paris. 


CLAss  IV  GASTROPODA  569 

Suborder  C.     PTEROPODA  Cuvier.i 

Nahed  or  shell-covered,  hermaphroditic,  pelagic  Mollusca,  without  distinct  head.  Eyes 
riidimentary,  and  foot  modified  so  as  to  forra  tvjo  lateral,  wing-like  fins,  situated  on  the 
anterior  end  of  the  hody.     The  gills  are  placed  hehind  the  heart. 

The  body  of  these  free-swimming  Mollusca  is  sometinies  elongated,  sometimes  coiled 
posterioiiy  in  a  si>iral.  In  some  instances  it  is  covered  by  a  thin  transparent  sliell 
{Thecosomata),  biit  oftener  it  is  naked  (Gymnosomata).  The  creatures  associate  in  vast 
swarms  in  the  open  sea,  and  rise  to  the  surface  toward  nightfall.  Their  shells  often 
accumulate  in  prodigioiis  quantities  on  the  sea-bottom,  forming  calcareous  deposits  of 
considerable  magnitude. 

C 11  vier  recognised  the  Pteropods  as  an  independent  class  of  Mollusca,  having  equal 
rank  with  the  Gastropods.  Modern  researches,  however,  have  approximated  theni 
niore  closely  to  the  latter  througli  the  swimming  Opisthobranchs.  If  \ve  regard  it  as 
probable  that  invertebrate  life  began  in  the  sea,  it  almost  certainly  follows  that 
Pteropods  are  among  the  earliest  Mollusca.  Also,  granting  that  the  conditions  of 
their  existence  have  undergone  no  appreciable  change  since  the  ocean  becanie  capable 
of  sustaining  such  pelagic  life,  there  is  no  obvious  reason  why  the  members  of  the 
group  should  have  since  experienced  any  radical  modification, 

The  earlier  paleontologists,  d'Archiac,  de  Verneuil,  Sandberger,  Barrande  and 
others,  recognised  the  true  relations  of  the  Paleozoic  Pteropods,  though  uniting  with 
them  some  forms  of  similar  appearance,  which  probably  are  not  of  niolluscan  nature, 
such  as  Conularia,  and  perhaps  Tentaculites. 

Neumayer  and  Pelseneer,  led  by  preconceived  theories,  have  objected  to  the  union 
of  Paleozoic  forms  like  Hyolithes  with  the  Pteropods,  though  proposing  no  satisfactory 
alternative  ;  and  by  a  curious  reversal  of  paleontologic  succession,  have  wished  to 
derive  the  Pteropoda  from  the  more  modern  Opisthobranchs.  Since  the  anatomy  of 
the  Cambrian  forms  seemed  inaccessible,  the  uncertainty  bade  fair  to  remain  permanent, 
when,  by  the  discovery  of  the  wonderful  Middle  Cambrian  deposits  of  the  Canadian 
Rocky  Mountains,  among  the  otlier  fossils  showing  traces  of  the  soft  parte,  were  found 
several  specimens  of  Hyolithes  carinatus  Matthew,  with  distinct  and  clear  impressions 
of  the  pteropodia.  These,  judging  from  the  sharpness  of  their  anterior  margins,  seeni 
to  have  had  there  some  kind  of  a  chitinous  support,  perhaps  like  the  chitinous  rods 
supporting  the  gill-lamellae  of  some  Nuculidae.^  This  wholly  unexpected  confirmation 
of  the  earlier  view  as  to  the  relations  of  these  fossils,  falls  in  with  the  views  generally 
held  by  malacologists  as  to  the  derivation  of  the  swimming  Opisthobranchs  from  the 

^  Literature  (see  also  preceding  bibliograpliies)  :  Sandherger,  O.,  Die  Flossenfüsser  oder  Ptero- 
poda. Neues  Jahrb.  für  Mineral.,  pp.  8-25,  1847. — Barrande,  J.,  Piigiunculus,  ein  fossiles 
Pteropoden-Geschlecht.  Neues  Jahrb.  für  Mineral.,  pp.  554-558,  1847.— Systeme  Sibirien  du  centre 
de  la  Bolieme,  vol.  iii.  Pteropodes,  1867. — Salter,  J.  W.,  Menioirs  of  the  Geological  Survey  of 
Great  Britain,  vols.  ii.,  iii.,  1848,  ISQQ.—Seguenza,  G.,  Paleontologia  raalacologica  dei  terreni  terziarii 
del  distretto  di  Messina.  Pteropodi  ed  Eteropodi.  Mem.  Soc.  Ital,  Sei.  Nat.  Milano,  vol.  ii.,  1867. 
— Karpinsky,  A.,  Die  fossilen  Pteropoden  am  Ost- Abhang  des  Ural.  Mem.  Acad.  St.  Petersbourg, 
ser.  7,  vol.  xxxii.  pp.  1-20,  18Si.—Doll/us,  Q.  and  Ramond,  G.,  Liste  des  Pteropodes  du  terraiu 
tertiaire  parisien.  Mem.  Soc.  Malacol.  de  Belgique,  vol.  xx.,  \9>8b.  —  Walcott,  C.  D.,  Contribution 
to  Studies  on  tlie  Cambrian  Faunas  of  North  America.  Bull.  U.  S.  Geolog.  Survey,  vol.  iv.  No.  30, 
pp.  125-146,  1866.— The  Fauna  of  the  Lower  Cambrian  or  Olenellus  Zone.  Tenth  Ann.  Rept. 
U.S.  Geol.  Survey,  18^0.— Pelseneer,  P.,  Report  on  the  Pteropoda.  Report  Challenger  Expedition, 
Zoology,  vol.  xxiii.,  1888.— /«ie?/i,  Bull.  Soc.  Beige  de  Geol.  Palaeont.  et  Hydrol.,  vol.  iii.,  1889.— 
Blanckenhorn,  M.,  Pteropodenreste  aus  der  oberen  Kreide  Nord-Syriens  und  aus  dem  hessischen 
Oligocän.  Zeitschr.  Deutsch.  Geol.  Ges.,  vol.  xli.,  1889.— iVb^'(i^^  0.,  Revision  der  paläozoischen 
Hyolithiden  Böhmens.  Abhandl.  Böhm.  Ges.  Wiss.  [7]  vol.  iv.,  1891.— //oZm,  G.,  Sveriges  Kam- 
brisk-Siluriska  Hyolithidae  och  Conularidae.  Afhandl.  Sver.  geol.  Undersök.,  Ser.  C,  No.  112, 
1893.— AS^^a^er,  /.,  Monograph  of  British  Conulariae.  Palaeont.  Soc,  1^01  .  —  Walcott,  C.  D.,  Cam- 
brian Geology  and  Paleontology.     Smiths.  Mise.  Coli.,  1912,  vol.  Ivii.,  No.  5. 

-  A  figure  of  this  fossil  is  given  by  Walcott  in  Smithson  Mise.  Coli.,  1912,  vol.  Ivii.,  No.  5. 


570 


MOLLUSCA 


PHYLUM  VI 


same  stem  as  tlie  Pteropoda,  and  their  natural  association  with  the  latter  in  a  single 
large  group. 

Family  1.     Limacinidae  Gray. 

Shell  thin,  spiral,  sinistral,  with  vüreous,  paucispiral  operculum.  Tertiary  and 
Recent. 

The  genus  Limacina  Lam.  (Spirialis  Eyd.  and  Soul.  ;  Embolus  Jeffreys),  is  of 
sporadic  occurrence  in  the  Tertiary  (Eocene  and  Pliocene).  Valvatina  Watelet, 
includes  flat  sinistral  shells  from  the  Calcaire  Grossier  of  Paris,  and  Planorhella  Gabb 
comprises  similar  forms  from  the  Oligocene  of  San  Domingo. 


Family  2.     Oavoliniidae  Fischer. 

Shell  symmetrical,  thin,  vüreous,  ventricose,  pyramidal,  or  conically  tubiform,  but  not 
Spiral.     Cretaceous  to  Recent. 

GavoUna  Abildgaard  {Hyalaea  Lam. ;    Gamopleura  Bellardi)  (Fig.   1069).     Shell 

globose,  laterally  keeled  and  slit,  acuminate  pos- 
teriorly  ;  composed  of  two  unequally  arched  pieces, 
one  of  wliich  projects  helmet-like  above  the  otlier. 
Recent,  and  fossil  in  the  Italian  Miocene  and 
Pliocene. 

Glio  Linnaeus  (Gleodora  Peron  and  Lesueur ; 
Balantium  Benson  ;  Flabellum,  Poculina  Bellardi) 
(Fig.  1070,  A,  B).  Shell  somewhat  angular,  com- 
pressed  dorso-ventrally,  with  lateral  keels,  A  crest 
or  rib  generally  extends  longitudinally  along  the 
back,  and  usually  projects.  Upper  Cretaceous  to 
Recent.  A  common  fossil  in  the  Pliocene  of  Monte  Mario,  near  Rome,  and  in  the 
vicmity  of  Messina  and  Turin ;  also  in  the  Oligocene  of  the  Mayence  Basin,  and  in 
the  English  Crag. 


Fig.  1069. 
A,  Cavolina  (Hyalaea)  tridentata  Forsk. 
Recent.     B,  C,  C.  (Gamopleura)  taurinensis 
Sism.     Miocene  ;  Turin,  Italy. 


Fig.  1070. 

A,  Clio  (nieodora't   mimmhintn    t  ,•«„      -dt  ^'    ^"""^s^^s    recta    Lesueur.      Recent    (after 

MonteMaroSrRomrR  %/?«•;    ^ '^^^"6  ;  A^lams).    B,  Styliola  striatulaNova\^.    Devonian 

cnr.L  A  idam?  ge^ent.   i^iSÄhellTaV;;  (f  ^'^f  H) ;  Hlubocep,  Boheniia.    3/,.     C,  Crese^s 

Adams).       C,    Vngindla    depr^.Ta  h^^^  '''''"'^;''   ^^"v,  ?«^?nian   (Etage  H) ;    Hostin, 

strang^latam.lrS    Mioceni'rSx^nJar  BoEx  TtlSent  "''i/r''     "'""'  -dividuals  on 

buTflthtiv  ^ntl  ITl?  T  ff  »t^y  «triated  ;  dorsal  groove  not  parallel  to  axis  of  the  shell 
1  ne  enSonrnnrT  n  °  /  •  ^''  ^''^■''''\  «^t^'e»^ity  (wlnch  ends  in  a  rostrum)  in  the  median 
line     embryonic  portion  ends  in  a  pomted  apex.     Tertiary  and  Recent. 

apeSlh-cuSr"'  ^     ^'  ^'^-     ^'"^''^'  '''^^  ^^"^^°"^  protoconch,   no  dorsal  groove, 


CLASS  IV 


GASTROPODA 


571 


In  the  Devonian  of  Bohemia,  Nassau,  Ural  and  North  America,  great  niimbers  of  smooth, 
circular,  longitudinally  striated  tubes  are  occasionally  met  witli,  the  posterior  end  of  whichis 
intlated  into  a  sniall  bulb.  Similar  tubos  have  also  been  described  by  Blankenhorn  froni  the 
Cretaceous  of  Syria.     None  of  these  differ  externally  to  any  great  extent  froni  Clio  or  Styliola. 


Vaginella  Daudiii  (Fig 
slightly  canaliculated  and 
Cretaceous  to  Recent. 

Guvierina     Boas ;     Triptera 
O.  Meyer).     Tertiary  and  Re(;ent 
Fisclier.     Eocene. 


1070,  C).      Shell  long, 
compressed   laterally 


ventricose,  depressed  ;  aj)erture 
Cross-section    elliptical.       Upper 
AB  c 


Qiioy    {Tihiella 
Euchilotheca 


Fig.  1072. 
,  A,  B,  Hyolithes  elegans  Barr. 


Family  3.     Hyolithidae  Nicholson. 

Shell  symmetrical,  conical  or  pyramidal, 
straight  or  sharply  hent ;  cross-section  triangulär, 
elliptical  or  lenticular ;  one  side  often  ßattened, 
and  the  other  arched  or  with  a  Munt  median  keel. 
Surface  smooth  or  ivith  fine  transverse  Striae,  rarely 
longitudinally  striated  or  ribhed.  Aperture  com- 
pletely  closed  by  an  operculum,  the  latter  being 
semicircular,  triangulär  or  lentiform,  with  lateral 
nucleus,  and   concentrically  striated ;    fteropodia, 

with  a   chitinous    support    to    the    anterior    edge.   f^^g  ^^''  1^°^«'"««'  B«^«"^^* 
Cambrian  to  Permian. 

According  to  Holm  the  typical  genus, 
Hyolithes  Eichwald  {Tlieca  Sowb. ;  Pugiunculus 
Barr.)  (Fig.  1072),  is  divisible  into  two  subgenera.  One  of  these,  Orthotheca  Noväk, 
contains  forms  with  an  abruptly  truncated  anterior  end  ;  and  in  the  other,  Hyolithes 
s.  Str.,  the  margin  of  the  flattened  side  projects  somewhat  above  the  opposite  wall. 
ABC  The  forms  known  as  Gleidotheca,  Gentrotheca  Salter, 
Gamerotheca,  Diplotheca  Matthew,  Pharetrella  Hall, 
Geratotheca  and  Bactrotheca  Noväk,  fall  within  the 
synonymy  of  Hyolithes.  TJiis  genus  is  abundantly 
distributed  in  the  Cambrian,  Ordovician  and  Silurian 
of  North  America,  Great  Britain,  Sweden,  Russia  and 
Bohemia ;  it  occurs  sparingly  also  in  the  Devonian, 
Carboniferous  and  Permian. 

Pterotheca  Salter  ;  Phragmotheca  Barrande.    Silu- 
rian ;  Europe.     Matthewia  Walcott.     Cambrian. 


Ordovician  ; 
Slightly  re- 
C,  H.  tnctximas  Barr.  Caiiibrian 
(Etage  C) ;  Mleschitz,  Bohemia.  Anterior 
portion  restored,  with  operculum,  and  viewed 
from  the  side.  1/2.  D,  Operculum  (after  Bar- 
rande). 


Fig.  1073. 

A,  TentacuUtes  scalarif 
Schloth.  Erratic  block  of 
Ordovician  age  ;  Berlin.  B, 
T.  orwitiis  Sowb.  Silurian  ; 
Dudley,  England.  C,  T. 
rtrudritfs  Rieht.  Silurian  con- 
cretion  ;  Thuringia.  A 
smaller  individual  contained 
within  the  larger  (after 
Xovak).  « 


Suborder  D.    CONULARIIDA  Miller  and  Gurley. 

Paleozoic  forms  of  doubtful  systematic  position, 
resembling  some  Recent  Pteropoda,  but  probably  to  be 
regarded  as  a  parallel  rath^r  than  as  an  identical 
group. 


Family  1.     Tentaculitidae  Walcott. 

Thick  -  walled,  ,  tapering,  elongate,  conical  tubes, 
having  a  circular  cross-section,  and  terminating  posteriorly  either  acutely  or  in  an 
embryonal  bulb.  Surface  ornamented  with  parallel  raised  transverse  rings.  TJie  apicaJ 
portion  of  the  shell  often  filled  with  calcareous  matter,  or  divided  off  by  transversr  a<  fiia. 
Ordovician  to  Devonian. 


572 


MOLLUSCA 


PHYLÜM  VI 


Tentaculites  Schloth.  (Fig.  1073).  This,  the  solitary  genus,  is  prodigiously 
abuiidaiit  in  the  Siluriaii  and  Devon ian,  the  strata  being  sometimes  fairly  charged 
with  their  remains.  The  shell  is  composed  of  a  compact  outer  layer,  and  an  inner 
layer  made  up  of  thin  lainellae  running  parallel  with  the  external  surface. 
The  supposed  Tentaculites  described  from  the  Oligocene  by  Ludwig  and  Blankenhorn 
are  thin-shelled,  transversely  ribbed,  conical  tubes,  wliich  probably  belong  in  the 
neighbourhood  of  Styliola  or  Euchilotheca. 

Family  2.     Torellellidae  Holm. 

Thich  -  ivalled,  smooth,  transversely  or  longitudinally  striated,  straight  or  bent  tuhes, 
acutely  terminated  posteriorly,  and  without  opercula.     Cambrian  to  Silurian. 

Torellella  Holm.  Tubes  strongly  compressed,  flattened  at  both  ends,  elliptical  in 
cross-section,  and  with  fine  transverse  Striae  ;  composed  of  brownish-coloured  calcium 
phosphate.     Cambrian  to  Silurian  ;  Sweden. 

Hyolithellus  and  Salterella  Billings  ;  Coleolus  Hall ;  and  Goleoloides  Walcott,  from 
the  Lower  Cambrian  of  North  America,  probably  also  belong  here. 


Family  3.     Conulariidae  Walcott. 

Shell  rectüinear,  elongate- conical,  rectangular  to  rhomhic  in  cross-section,  with 
usually  sharp  edges,  acute  or  truncated  posteriorly.  Each  of  the  transversely  striated  or 
ribhed  lateral  faces  divided  into  longitudinal  halves  by  a  superficial  groove,  corresponding 
internally  to  a  median  ridge.  Posterior  portion  of  the  shell  divided  off  by  septa. 
Aperture  constricted  by  four  triangulär  or  linguiform  incurved 
lobes  of  the  anterior  margin.     Ordovician  to  Jura. 

Öonularia  Mill.  (Figs.  1074,  1075).  This,  the  solitary 
genus,  sometimes  attains  a  length  of  20  cm.,  and  is  represented 
by  about  100  species.  Its  maximum  distribution  occurs  in  the 
Ordovician  and  Silurian  of  Bohemia,  Normandy,  England, 
Sweden  and  North  America,  and  in  the  Devonian  of  North 
America  and  Bolivia.  It  is  rare  in  the  Carboniferous  and 
Permian,  and  the  last  surviving  species  occurs 
in  the  Trias  and  Lias. 


Order  2.     PULMONATA  Cuvier. 
Air-breathing  Snails.^ 

Euthyneura  in  which  the  gill  cavity  is 
transformed  into  a  lung  for  breathing  free 
air.     Mainly  terrestrial  or  fresh-water  forms. 

A  few  Pulmonates  have  reverted  to  ex- 

clusively  aquatic  habits,  and   have  the  lung 

filled  with  water ;    and  in  a  few,  secondary 

iTpper  Carboniferous  gills  are    developed    in    the    cavity.      These, 

Limestone;  Glasgow,     i,^,,,^,,^^      „_      J_      .^„_^;.„.         rvi. .„^ 


Fig.  1075. 

Conularia     quad- 


risulcata 


5owb. 


Fio.  1074. 


Conularia  anginala  Barr, 
Ordovician  (Etage  D) 
Drabov,  Bohemia. 


Scotiand.     showing   however,    are    rare    exceptions.      The    great 
weii-preseryed  aper-   majority  of  forms  breathe  air  by  means  of  a 

tural  margms  (after         .         i         n    n       i  ■,  '^■,  ^i 

Etheridge).  network    Ol   blooQ  -  vessels»  spread    upon    the 

inner  surface    of   the    lung.      The    ordinary 
aquatic  forms  come  to  the  surface  of  the  water  at  intervals  to  renew  their  supply  of 

^  Sandherger,  F.,  Land-  und  Siisswasser-Conchylien  der  Vorwelt.  1870-75.  — TFMe  CA., 
Review  öf  American  non-marine  Mollusca.  3rd  Ann.  Rep.  U.S.  Geol.  Surv.,  1881-82.— Tryow, 
O.  W.  and  Pilshry,  H.  A.,  Manual  of  Conchology,  Puhmnata. 


CLASS  IV 


GASTROPODA 


573 


air.  The  Pulmonates  have,  witli  few  exceptions,  no  operculiim,  and  the  sliell  is  often 
vestigial  or  absent. 

Next  to  the  Prosobranchs  the  Pulmonates  are  the  largest  group  of  Gastropods, 
there  being  upwards  of  6000  living  and  700  fossil  species  known.  The  most 
important  and  highly  diversified  genera  {Helix,  Bulimus,  Ölausilia)  are  terrestrial  in 
habit ;  certain  others  {Planorhis,  Lymnaea,  Physa)  are  confined  to  fresh  water.  The 
oldest  Piilmonates  are  of  rare  occurrence  in  the  Devonian  and  Carboniferous  ;  they 
are  found  sparingly  in  the  Jura  and  Cretaceous,  are  of  greater  abundance  in  the 
Tertiary,  but  do  not  attain  their  maximum  distribution  until  the  present  geological 
period. 

The  Thalassophila  and  Auriculidae  are  restricted  to  marine  deposits ;  the  re- 
maining  Pulmonates  are  rarely  found  except  in  fresh-water  strata,  and  are  commonly 
associated  with  other  organisms  that  have  been  swept  by  rainfall  or  running  water 
into  swamps  or  estuaries. 


Suborder  A.     THALASSOPHILA  Gray. 

Shell  either  spiral  and  operculate,  or  bowl-shaped  to  depressed  conical,  ivithout  spire, 
and  somewhat  unsymmetrical.  Animal  usually  provided  with  a  single  gill  in  addition 
to  the  lung  cavity.     Tentacles  fused  with  the  discoidal  head.     Eyes  sessile. 

The  Thalassophila  inhabit  the  littoral  zone  of  the  ocean  and  brackish  estuaries. 
Fossil  remains  occur  from 
the  Devonian  onward. 
Three  families  are  recog- 
nised — Siphonariidae,  Gadi- 
niidae  and  Amphibolidae, 
but  these  are  not  readily 
distinguishable  by  shell 
characters  alone. 

Siphonaria  Blainville 
(Fig.  1076).  Shell  usually 
radially  ribbed.  Apex 
directed  backwards  or  to- 
ward  the  left  side ;  inter- 
nally  with  two  unequal  muscular  impressions,  which  are  interrupted  on  the  right 
side  in  front  by  a  broad  groove.     Tertiary  and  Recent. 

Hercynella  Kayser  (Fig.  1077).  Devonian.  Anisomyon  Meek  and  Hayden.  Jura 
and  Cretaceous. 

Valenciennesia  Rousseau.  Shell  very  thin,  broadly  bowl-shaped,  concentrically 
ribbed.  Apex  situated  near  the  posterior  margin.  Right  side  bearing  a  broad 
plication  for  the  respiratory  tube.  Found  in  brackish  water,  Congerian  Stage  (Pliocene) 
of  Hungary,  Roumania  and  South  Russia. 

Williamia  Monts. ;  Gadinia  Gray.     Recent  and  Pliocene. 

Amphihola  Schum.  Shell  spirally  globose,  thick,  rugose  and  operculate.  Recent. 
This  is  placed  in  a  separate  family,  the  Amphibolidae. 


Fig.  1077. 


Siphonaria  crassicosfata  Desh. 
Eocene  ;  Anvers,  near  Paris. 


Herc^jnella  bohemica  Barr.    Devonian 
(Etage  F) ;  Lochkow,  Bhemia. 


Suborder  B.     BASOMMATOPHORA  A.  Schmidt. 

Shell  invariably  present.     Eyes  situated  at  the  base  of  a  pair  of  tentacles. 
or  living  in  the  vicinity  of  water. 


AquatiCj 


Family  1.     Auriculidae  Blainville. 

Shell  thick,  ovate.     Spire  short,  body  whorl  very  large.     Inner  lip  or  columella  bear- 
ing plications.     Shore  forms  or  inhabitants  of  sali  marshes.     Jura  to  Recent. 


574 


MOLLUSCA 


PHYLLTM  VI 


Äuricula  Lani. 
roimded  anteriorly 
times  denticulated. 

Gassidula  Fer,  : 
(Fig.  1080) ;  Melampus  Montf. 

Garychium    Müller    (Fig.   1081), 


(Fig.    1078).     Elongate-oval,  with  epidermis.      Aperture  narrow, 
Inner  lip  bearing  two  or  tliree  folds  ;  outer  lip  thickened,  sonie- 
Jura  to  Kecent. 
Plecotrema  Adams ;  Alexia  Leach   (Fig.  1079);  Pythio'psis  Sandb. 


Shell   small,  smooth    and    glossy.      Inner    lip 


Fig.  1079. 


Fig.  107 

Äuricula  dutemplei 

Deshayes.       Lower  Alexia  pisoliim  Desli. 

Eocene ;     Sainceixx  Miocene ;    Pontlevoy, 

(after  Deshayes).  Touraine.    ^/i. 


Fi(i.  lOSl. 

Pythiopsis     la-  Carychium  antiquum 

marcki      (Desh.).  A.  Braun.     Miocene; 

Eocene ;       Houdan  Hochheini,  near  May- 

(after  Deshayes).  euce.     Enlarged. 


bearing  one  or  two  folds ;  outer  margin  thickened,  sometimes  with  a  tooth.     Jura  to 
Kecent.     Terrestrial. 

Scarahus  Montf.   (Polyodonta   Fischer   von  Waldh.) ;   Leuconia  Gray ;   Blauneria 
Shuttlewortb,  etc.     Tertiary  and  Eecent. 


Family  2.     Chilinidae  Dali. 

Shell  oval,  auriculate,  with  large  aperture,  the  columellar  marcjin 
provided  with  spiral  folds ;  surface  coloured  in  various  patterns. 
Tertiary  and  Recent. 

Ghilina  Gray.  This  is  said  to  be  Streptoneurous.  The 
dentition  resembles  that  of  Physa.  Miocene  and  Recent ;  South 
America. 

Family  3.     Physidae  Dali. 

Shell  sinistral,  oval,  glossy,  unicoloured.  Aperture  large;  colu- 
mella  twisted  or  simple.     Jura  to  Recent. 

Physa  Drap.  (Fig.  1082).  Shell  brilliantly  polished,  thin, 
sinistral.     Upper  Jura  to  Recent. 


Fig.  1082. 

Physa  gigantea 
Michaud.  Lower 
Eocene ;  Rilly,  near 
Rheims. 


Family  4.     Lymnaeidae 
Keferstein. 

Shell  thin,  turreted.  or  dis- 
coidal.  Fresh-water  inhahitants. 
Lias  to  Recent ;  especially  abun  - 
dant  in  the  Tertiary. 

Lymnaea  Lam.  {Limnaeus 
auct.)  (Fig.  1083).  Shell  very 
thin  and  corneous.  Body  whorl 
very  large ;  spire  acute,  and 
moderately  high.  Aperture  wide,  oval 
to  Recent ;  maximum  in  Tertiary. 

Planorhis  Guettard  (Figs.   1084,  1085), 


Fig.  1083. 

Lymnaea  pachygaster 
Fresh  -  water 
Miocene ;     Mörsingen, 
near  Ulm. 


Thom. 


JlFiG.  1084. 

Planorhis  cornu  Brongt.  var.  mantelli 
Dnnker.  Upper  Miocene;  Mundingen, 
Wiirtemberg. 


outer  margin  sharp.      Upper  Jura  (Purbeck) 
Discoidal  (exceptionally  turreted),  with 


CLASs  IV  GASTROPODA  575 

many    whorls.     Aperture    oval    to    crescent-shaped ;    outer   margin    sharp.     Lias    to 
Recent ;    very  profuse  in   the  Tertiary.      P.  multiformis  (Bronn),  from   the   Middle 


^^ 


Fig.  1065. 

Planorbis   multiformis   (Bronn).      Upper  Miocene    fresh-water  limestone;   Steinheim,  near    Heidenheim, 
Würt«mberg.     A,  var.  suprema.    B,  var.  trochifonnis.     C,  var.  elegans.    D,  var,  steinheimensis. 

Miocene  of  Steinheim  in  Würtemberg,  is  particularly  interesting  on  account  of  its 
extraordinary  variability.  The  different  mutations  of  the  species  are  usually  found 
at  different  liorizons  of  the  fresh-water  limestone  occurring  there,  and  constitute, 
according  to  Hilgendorf  and  Hyatt,  a  remarkable  genealogical  sequence. 

Isidora  Ehr.     Shell  siniilar  to  that  of  Physa.     Recent ;  tropical  countries. 

Family  5.     Ancylidae  Dali. 

Shell  liiiqiet-shaped,  conical^  not  spiral,  or  with  the  apex  recurved.  Tertiary  and 
Recent. 

Ancylus  Geoftrey  (Fig.  1086).  Shell  simply  conical  or  with  the  apex  slightly 
incurved.     Tertiary  and  Recent. 

Gundlachia  Pfeiff.     A  partial  septum  is  developed  at  the  end  of 
the  first  season's  growth.     Tertiary  of  Mayence  Basin  and  Recent. 

Suborder  C.     TELETREMATA  Pilsbry. 

Shell  ahsent ;  mantle  covering  the  whole  upper  surface  of  the  body. 
Male  and  female   orißces  widely  separated ;    lung  orifice  and    anus  ^^^'  ^^^^- 

ventral  and  near  the  tau.  DelÄcfiS:? 

Several  families   of   this  suborder  are  recognised  {Vaginulidae,   ^^^^ "    oursau  . 
Rathouisiidae,  Onchidiidae),  but  owing  to  the  absence  of  a  shell,  their  remains  are 
not  preservable  in  the  fossil  State. 

Suborder  D.     STYLOMMATOPHORA  A.  Schmidt.     Land  Snails. 

Eyes  hörne  on  the  extremüies  of  two  peduncleSy  which  are  capahle  of  invagination  ; 
a  pair  of  short  tentacles,  rarely  obsolete,  are  placed  in  front  of  them.  Male  and  female 
genital  orißces  contiguous,  or  uniting  in  a  common  vestibule,  situated  at  the  right  or 
left  side  of  the  head.  Buccal  retractors  present ;  lung  foram^n  and  anus  anterior  to  the 
end  of  the  foot,  not  ventral. 

This  suborder  comprises  most  recent  and  all  fossil  land  snails,  and  is  divisible 
into  series  or  superfamily  groups.  The  families  proper  are  based  almost  wholly  upon 
characters  of  the  soft  anatomy,  which  are  herein  largely  omitted  or  abridged. 

Superfamily  1.     HOLOPODA  Pilsbry. 

No  longitudinal  grooves  above  the  margins  of  the  foot ;  jaw  present,  teeth  quadrate. 

Family  1.     Helicidae  Keferstein.     Helices. 
Shell  depressed,  globose  or  oval  and  elevated.     Tertiary  and  Recent 

This  comprises  an  enormous  assemblage  in  the  Recent  fauna,  but  most  of  the  genera 
have  not  as  yet  been  found  fossil.     All  the  typical  forms  will  probably  in  time  be 


576 


MOLLUSCA 


PHYLUM  VI 


traced  back  to  tlie  Eocene.     Subfamily  and  generic  characters  are  based  largely  upon 
the  genital  System,  and  hence  are  of  little  practical  importance  to  the  paleontologist. 


Polygyra    Say.      Globose    or    depressed, 
Oligocene  to  Eecent ;  North  America. 

Sagda   Beck.      Glossy,  with   many   close 


Fig.  1087. 

A,  Ilelix  (DniiorplioptycMa)  arnouldi  Michaud.  Lower 
Eocene  ;  Rilly,  near  Rheims.  B,  Helix  (Campylaea)  inflexa 
Klein.  Upper  Miocene  ;  Mörsingen.  C,  Helicodonta  osculum 
Thoni.     Lower-  Miocene  ;  Hochheim,  near  Wiesbaden. 


with    the    lip    reflected,    often    toothed. 

whorls,  the  last  usually  with  internal 
laminae  and  a  sharp  lip.  Oligocene  to 
Eecent ;  Antilles. 

Pleurodonta  Fischer  von  Wald. 
Solid,  large,  depressed  and  generally 
keeled  ;  aperture  often  toothed.  Oligo- 
cene to  Eecent ;  Antilles,  Florida. 

Helix  Linn.  (Fig.  1087,  Ä,  B). 
Shell  semi-globose,  conical  to  discoidal, 
manifesting  great  variability  of  form. 
Aperture  oblique,  crescentic  or  rounded, 
with  disconnected  margin  s.  Very  pro- 
fuse in  the  Tertiary  and  Eecent  of  Europe  and  adjacent  regions  of  Asia  and  Africa. 

Helicodonta    Fer.    (Fig.    1087,    G).     Similar    to    Helix,   but   with    thickened    or 
denticulated  lip.      Oligocene  to  Eecent ;  Europe. 

Other  allied  genera  occur  in  European  Tertiary  deposits. 
Eecent  Helicidae  reproducing  by  extraordinarily  large  eggs  are 
the  foUowing :  Helicophanta  of  Madagascar,  Acavus  of  Ceylon, 
Panda  of  Australia,  and  Strophocheilus  of  South  America. 


Family  2.     Bulimulidae  Fischer. 

Shell  elongated,  ovate,  with  narroio  umhilicus  or  none.     Ter- 
tiary and  Eecent. 

Bulimulus  Leach.     Oligocene  to  Eecent ;  America.     Amphi- 
dromus  Alb.     Tertiary  ;  Europe  and  Asia. 


Family  3.     Pupidae  Albers. 

Shell  small,  cylindrical  or  oval,  with  narroio  whorls.    Tertiary 
and  Eecent ;  also  in  the  Carboniferous. 

Glausilia    Drap.    (Fig.    1088).     Shell    turreted    to 
Aperture  pyriform,  with  usually  continuous  peristome. 


lOSS. 

A,  Glausilia  hulimoides 
A.  Braun.  Lower  Miocene ; 
Eckingen,  near  Ulm.  B,  C. 
antiqua  Schübler.  Same 
locality. 


fusiform,  slender,  sinistral. 
Inner  lip  bearing  two  folds  ; 
outer  margin  somewhat  reflected  ;  the  aper- 
ture usually  closed  by  a  movable  calcareous 
plate.  Occurs  sparingly  fossil  from  the 
Eocene  onward,  and  represented  by  about 
400  Eecent  species. 

Pupa  Lam.  (Fig.  1089,  B).  Shell  small, 
cylindrical- ovate.  Aperture  semicircular, 
usually  constricted  by  teeth  on  the  colu- 
mella  and  inner  and  outer  lips.  The  outer 
margin  reflected.     Tertiary  and  Eecent. 

Dendropupa    Dawson    (Fig.    1089,    Ä). 
Like  the  last,  but  aperture  without  teeth. 
Upper  Carboniferous  ;  Nova  Scotia. 
Vertigo  Müller.     Tertiary  and  Eecent. 
Buliminus  Ehrb.  (Fig.  1090).     High  conical,  solid,  turreted.     Eocene  to  Eecent. 


Fig.  1089. 


vetusta 


A,  Dendropupa 
Dawson.  Goal  Measures ; 
Nova  Scotia  (after  Dawson). 
B,  Pupa  diversidens  Sandb. 
Miocene ;  Sansan,  Gers  (after 
Sand  berger). 


Fig.  1090. 

'Buliminus  (Petraeus) 
complanatus  Reuss. 
Lower  Miocene; 
Thalflngen,  near  Ulm. 


ci'Ass  IV  GASTROPODA  577 

Family  4.     Achatinidae  Pilsbry. 

Ovate  or  elongate,  imperforate  shells,  luüh  the  coluraella  generally  truncated  at  the 
hase.     Upper  Cretaceoiis  to  Receiit. 

Achatina  Lam.     Recent ;  tropical  Africa. 

Stenofjyra  Sliuttlew. ;  Rumina  Risso ;  Opeas  Alb.;  Rhodea 
Adams.      These  are  all  small  menibers  of  tlie  group,  mainly  Recent. 

Megaspira  Lea  (Fig.  1091).  Tiirreted,  sleiider,  very  long; 
columella  witli  transverse  folds.      Upper  Cretaceoiis  to  Recent. 

Gochlicopa  Fer.  ;  Äzeca  Leacli ;  Gaecilianella  Boiirg.,  etc. 
Tertiary  and  Recent. 

Superfamily  2.     AGNATHA  Mörch.  „  ^'"'  ^^^^- 

Megaspira    exarata 

Garnivorous  snails,  usually  with  no  jaiv,  thorn-shaped  teeth,  and   Eocene;  Riiiy°nelr 
without  furrows  above  the  f 00t 


Fig.  1093. 


Rheims. 


Family  1.     Testacellidae  Gray. 

Shell  Spiral,  of  very  small  size,  and  situated  near  the  tail  of  the 
^  vermiform  animal.     Tertiary  and  Recent. 

!^M  Testacella  Cuvier  (Fig.  1092).      Shell  auri- 

^^  form,  borne  on  the  posterior  end  of  the  animal. 

Fig.  1092  Tertiary  and  Recent. 

Testacella  zelUi  Klein.  ParmacelUna  Sandberger.     Eocene.     Daude- 

Miocene ;  Andeifingen  bardia      Hartm.        (Helicophanta      Fer.     xy.vX 

(after  Sandberger).  <^      ,  i   -r.  ,  i  i  y 

Quaternary  and  Recent. 

Family  2.     Glandinidae  Albers. 

Shell  oval  or  oblong^  capable  of  containing  the  entire  animal. 
Cretaceoiis  to  Recent. 

Glandina  Schum.  (Fig.  1093).  Shell  elongate-oval,  with  high 
spire.  Aperture  notched  in  front ;  columella  truncated.  Upper 
Cretaceous  to  Recent.      Other  Recent  allied  genera  inhabit   the   Reitl^'''uuZine'\ 

American  tropics.  Richelberg,  near  Ulm.' 

Superfamily  3.     AULACOPODA  Pilsbry. 

Foot  with  longitudinal  grooves  above  and  parallel  with  its  lateral  margins. 

Family   1.     Zonitidae  Pfeiffer. 

Aulacopoda  with  a  spiral,  conical  or  helicoid  shell,  sometimes  partially  uncoiledj 
usually  smooth  and  loith  simple  lip ;  marginal  teeth  of  the  radula  thorn-like ;  foot 
margin  wide ;  jaiv  rather  smooth.     Carboniferous  (?)  to  Recent. 

Vitrina  Drap.  Shell  small,  translucent,  with  short  spire,  and  very  large  body 
whorl.     Tertiary  and  Recent. 

Archaeozonites  Sandb.  (Fig.  1094).  Thick-shelled,  globose,  with  rather  high  spire, 
deeply  umbilicate  ;  outer  margin  sharp.  Oligocene  and  Miocene.  Here  also  should 
be  placed,  perhaps,  the  archaic  üTßZiic-shaped  snails  from  the  Goal  Measures  of  Nova 
Scotia. 

VOL.  I  2  V 


5 78  MOLLUSCA  phylüm  vi 

Zonites  Montf.     Like   the   last,  biit  with  thinner  shell,   graniilatecl   above,   and 
smooth  below.     Tertiary  and  Recent. 


Fig.  1095.  Fig.  1096. 

Archaeozonites    subverticillui!  HyaUnia     denudata  Lychnus     matheroni      Requien. 

Sandb,       Lower    Miocene;  (Reuss).         Miocene ;  Upper  Cretaceous    (Gariimnian) ; 

Bckingen,  near  Ulm.  Tuchoritz,  Bohemia.  Rognac,  Provence. 

Hyalinia  Fer.  (Fig.  1095)  ;  Omphalosagda  Sandb. ;  Ariophanta  Desm.  ;  Trocho- 
morpha  Albers.      Tertiary  and  Recent. 

Lychnus  Montf.  (Fig.  1096).  Body  wliorl  large,  bent  upward  at  first,  and  later 
decurved,  so  tbat  the  margins  of  tbe  aperture  lie  in  the  basal  plane.  Upper 
Cretaceous  of  Provence  and  Spain. 

Family  2.     Limacidae  Lamarck. 

NaJced  slugs  having  a  small  vestigial  shell,  ßat  and  non-spiral,  concealed  within  the 
mantle,  which  latter  forms  a  small  oval  shield  on  the  forepart  of  the  hody.  Foot  margin 
narrow ;  dentition  and  jaw  as  in  the  Zonitidae.     Tertiary  and  Recent. 

The  principal  genera  are  Limax  Linn.,  in  which  the  intestine  has  four  longi- 
tudinal  folds,  and  the  back  is  keeled  at  the  tail  only ;  and  Amalia  Moq.-Tand.,  with 
Spiral  gut  and  strongly  keeled  back.  Their  small  scale-like  shells  have  been  found 
in  the  Tertiary  and  Pleistocene  ;  present  distribution  nearly  world-wide. 

Family  3.     Endodontidae  Pilsbry. 

Shell  Spiral  and  external,  varying  from  cylindric  to  helicoid  and  planorhoid,  usually 
rih-sculptured  and  with  opaque  colouring ;  lip  thin,  unex2)anded.  Jaiv  of  separate  or 
united  imbricating  plates,  or  solid  and  striated ;  marginal  teeth  squarish ;  genitalia 
without  accessory  organs.     Carboniferous  to  Recent. 

Punctinae.  Jaw  of  numerous  separate  plates ;  shell  minute.  Includes  the 
Holarctic  genera  Punctum  Morse  and  Sphyradium,  Charp.,  also  the  New  Zealand 
genus  Laoma  Gray.     Recent. 

Endodontinae.  Jaw-plates  united  more  or  less  completely.  Genera  :  Fyramidula 
Fitz.  Discoidal  or  low  conical,  with  tubulär  ribbed  whorls  and  open  umbilicus. 
Carboniferous  to  Recent.  This  is  one  of  the  most  ancient  land  Mollusks  known,  and 
is  the  oldest  Helicoid  form.  Phasis,  Ämphidoxa,  Flammulina  and  Endodonta  Alb. 
are  similar  austral  forms,  but  are  only  known  Recent. 

Family  4.     Arionidae  Gray. 

Slugs  having  the  shell  rediiced  to  a  ßat  plate  or  a  few  granules,  nearly  or  entirely 
concealed,  or  ahsent.  Mantle  in  the  form  of  a  shield  on  anterior  part  of  the  hody ;  teeth 
of  the  quadrate  type.     Recent. 

This  family  is  probably  derived  from  the  Endodontidae  by  degeneration  of  the 
shell.  Ärion  Fer.,  and  Änadenus  Heyn,  are  leading  genera  of  Europe  and  Asia  ; 
Ariolimax  Mörch,  and  Prophysaon  Bland  occur  abundantly  in  North  America. 


CLA>ss  IV  GASTROPODA  579 

Family  5.     Philomycidae  Gray. 

Slugs  someiühat  similar  to  Arionidae,  hut  the  mantle  Covers  the  entire  U2)per  surface 
of  the  body.      Ä  shell  is  completely  ahsent ;  hence  no  fossil  forms  are  hnown. 

Superfamily  4.     ELASMOGNATHA  Mörch. 

Jaio  vnth  a  strong  squarish  process  of  attachment  ahove. 


Family  1.     Succineidae  Albers. 
Shell  thin,  ovate^  consisting  of  few  whorls. 


Fig.  1097. 


Succinea  Pfeiffer  (Fig.  1097).  Shell  thin,  ovate,  amber-coloured,  SiuTinea  peregHna 
transluceiit,  witli  short  spire  and  large  body  whorl.  Outer  margin  cene;'  Tuchoritz, 
of  apertiue  sharp.     Tertiary  and  Recent ;  abundant  in  the  Loess,         Bohemia. 

Range  and  Distribution  of  the   Gastropoda. 

Of  all  classes  of  Mollusks,  the  Gastropods  exhibit  the  most  manifold 
variety.  Beginning  in  the  Cambrian,  they  acquire  a  very  gradual  increase 
and  distribution,  and  are  at  present  enjoying  their  maximum  vigour.  There 
exist  probably  over  20,000  Recent  species,  about  thtee-fifths  of  which  have 
gills,  the  remainder  being  air-breathers. 

At  the  base  of  the  Cambrian  (Olenellus  zone)  are  found  such  archaic 
genera  as  Scenella,  Stenotheca,  Platyceras,  Bhaphistoma,  Pleurotomaria ;  a  number 
of  Pteropods  with  some  doubtful  forms  {Hyolithes,  Hyolithellus,  SaltereUa,  Torel- 
lella, etc.),  which  evince  the  great  antiquity  of  the  Aspidobranchs ;  and  forms 
resembling  the  Capulidae.  In  the  later  Cambrian  the  Rhipidoglossa  (represented 
by  the  Plemvtomariidae,  Euomphalidae  and  B eller ophontidae)  predominate ;  and 
associated  with  these  are  certain  Pteropod  remains,  members  of  the  Capulidae, 
and  a  few  genera  probably  referable  to  the  Turhinidae.  A  notable  genus 
occurring  here  is  Subulites,  which  bears  some  resemblance  to  the  Pyramidellidae, 
and  exhibits  a  distinct  channelling  at  the  base  of  the  columella. 

Unfortunately  the  poorly  preserved  remains  of  Cambrian  Gastropods  afFord 
but  scanty  information  regarding  the  disposition  of  the  soft  parts  ;  neverthe- 
less  there  are  good,  although  purely  theoretical  reasons  for  supposing  that 
the  Rhipidoglossa  and  Ctenobranchs  were  formerly  not  so  widely  separated  as 
at  present. 

During  the  Ordovician  and  Silurian,  Gastropods  increased  perceptibly  in 
the  number  of  species,  and  a  few  new  families  were  initiated  (Epitoniidae, 
Purpurinidae,  Trochidae,  Xenophoridae) ;  but  the  faunal  aspect  remained  on 
the  whole  much  the  same  as  in  the  Cambrian,  and  no  essential  changes  were 
introduced  during  the  remainder  of  the  Paleozoic.  Accordingly,  the  Paleo- 
zoic  Gastropod  fauna  may  be  said  to  be  characterised  by  its  general  simplicity, 
being  made  up  principally  of  Pteropods,  Rhipidoglossa,  -a  few  Docoglossa 
and  Opisth'obranchs,  and  also  a  scattering  representation  of  Ctenobranchs 
(Capulidae,  Pyramidellidae,  Littorinidae). 

During  the  Jura-Trias,  the  large,  thick-shelled  varieties  of  Pteropod-like 
Mollusks  became  extinct.  But,  on  the  other  hand,  various  families  of  the 
Rhipidoglossa  reached  the  acme  of  their  development  {Pleurotomariidae,  Tur- 
hinidae, Nerilopsidae,  Neritidae);    and  among  the   Ctenobranchs,  the  families 


580  MOLLUSCA  phylum  vi 

TABLE  SHOWING  THE  VERTICAL  EANGE  OF  THE  GASTROPODA. 


Fainilies. 

c 
Xt 

'> 
o 

1 

i 

i 
1 

Ä 

1 

1 

d 
^ 

o 

4i 

1.  Streptoneura 

Order  1.  Aspidobranchia 

A.  Docoglossa  . 

B.  RMpidoglossa 

1.  Haliotidae 

2.  Pleurotomariidae     . 

3.  Fissurellidae  . 

4.  Euomphalidae 

5.  Raphistomidae 

6.  Stomatiidae    . 

7.  Turbinidae 

8.  Phasianellidae 

9.  Delphinulidae 

10.  Trochonematidae    . 

11.  Trochidae       \ 

12.  Umboniidae    . 

13.  Neritopsidae  . 

14.  Neritidae 

Order  2.  Ctenobranchia 

A.  Heteropoda. 

B.  Platypoda 

1.  Eulimidae 

2.  Pyramidellidae 

3.  Epitoniidae    . 

4.  Solariidae 

5.  Purpurinidae  . 

6.  Littorinidae    . 

7.  Cyclostomidae 

8.  Capulidae 

9.  Naticidae 

10.  Xenophoridae 

11.  Ampullariidae 

12.  Valvatidae      . 

13.  Viviparidae    . 

14.  Hydrobiidae   . 

15.  Rissoidae 

16.  Turritellidae  . 

17.  Vermiculariidae 

18.  Caecidae 

19.  Melaniidae      . 

20.  Nerineidae      . 

21.  Cerithiidae      . 

22.  Aporrhaidae    . 

23.  Strombidae     . 

24.  Columbellariidae     . 

— 







^^^ 







— 

..? .. 





1 

..  ? .. 





^^^ 

— 

— 









1 

^—^ 











— 

: 







— . 

' 









! 1 

1 

j 



___^ 



— 



1 
i 

— 

i 

— 

1 

( 

i 



CLASS  IV 


RANGE  OF  THE  GASTROPODA 


581 


Families. 

ä 

aS 

1 

ä 
.2 

i 
1 

CO 

i 

1 

s 
.SS 

1 

i 

1  ^ 

•-» 

1 
1 

■i 

'i 

25.  Cypraeidae 

26.  Ovulidae 

27.  Cassididae 

28.  Doliidae 

29.  Nyctilochidae 

30.  Columbellidae 

31.  Buccinidae 

32.  Muricidae 

33.  Thaisidae 

34.  Fusidae  . 

35.  Vasidae  . 

36.  Volutidae 

37.  Harpidae 

38.  Olividae 

39.  Cancellariidae 

40.  Terebridae      . 

41.  Turritidae       . 

42.  Conidae  . 

2.  Euthyneura 
Order  1.  Opisthobranchia 

B.  Tectihranchiata 

1.  Acteonidae 

2.  Ringiculidae  , 

3.  Akeratidae 

4.  Hydatinidae  . 

5.  Bullariidae     . 

6.  Acteocinidae  . 

7.  Scaphandridäe 

8.  Philinidae       . 

9.  Umbraculidae 

C.  Bteropoda 

1.  Limacinidae    . 

2.  Cavoliniidae  . 

3.  Hyolithidae    . 

D.  Conulariida 

1.  Tentaculitidae 

2.  Torellellidae  . 

3.  Conulariidae  . 

Order  2.  Pulmonata 

A.  Thalassophila     . 

B.  Basominatophora 

1.  Auriculidae     . 

2.  Chilinidae       . 

3.  Physidae 

4.  Lymnaeidae    . 

5.  Ancylidae 

C.  Teletrcmata 

D.  Stylommatophora 

1 

! 

1 

1 

i 

1 

• 

1 

i 

i 



1 

1 





— 

— 



— 

■  — 

^ 



— 

1 

1 
1 

~~i 



^— 

"" 



— 

— 



1 



— 

— 

— 

— 





1 

1 

1 



— 

1 

— 

1 

1 

i 

582  '  MOLLUSCA  phylum  vi 

Pyramidellidae  Nerineidae,  Purpurinidae,  TurriteUidae  and  Aporrhaidae  multi- 
plied  in  a  great  variety  of  forms. 

The  Cretaceous  witnessed  a  decided  increase  among  the  siphonostomous 
Ctenobranchs,  and  in  the  Tertiary  this  branch  asserted  itself  as  the  dominant 
type  of  Gastropods,  surpassing  all  other  families  in  point  of  numbers,  and 
gradually  acquiring  the  aspect  of  living  genera  and  species.  The  Nerineidae, 
Pyramidellidae  and  Aporrhaidae,  which  played  such  a  prominent  role  along 
with  the  Rhipidiglossa  during  the  Mesozoic  era,  became  in  part  extinct  in  the 
Tertiary,  and  the  remainder  entered  upon  their  decline.  The  great  majority 
of  Eocene  and  Oligocene  genera  are  still  living,  but  the  species  have  with 
very  few  exceptions  become  extinct.  During  the  Miocene,  more  species  made 
their  appearance  which  are  still  in  existence,  and  of  the  Pliocene  species, 
between  80  and  90  per  cent  are  represented  in  the  Recent  fauna. 

The  geological  history  of  the  Pulmonata  is  remarkable.  Thalassophilous 
Siphonariidae  are  first  met  with  in  the  Devonian,  where  they  are  very  sparse. 
Land  snails  (Archaeozonites,  Pyramidula,  Dendropupa)  were  initiated  in  still 
smaller  numbers  during  the  Carbon iferous;  but  not  until  the  boundary  between 
the  Jura  and  Cretaceous  is  reached  do  we  find  any  traces  of  fresh-water  snails. 
We  meet  them  first  in  the  Purbeck.  In  the  Wealden,  and  Cretaceous  gener- 
ally,  both  land  and  fresh-water  Gastropods  are  quite  abundant ;  they  became 
highly  developed  and  widely  distributed  during  the  Tertiary,  attaining,  in  fact, 
a  differentiation  nearly  equal  to  that  exhibited  by  the  corresponding  Recent 
forms. 

The  successive  approximations  to  present  conditions  among  Gastropod 
faunas  have  not  been  confined  to  the  production  of  forms  simulating  more  and 
more  those  now  living ;  they  include  also  the  gradual  demarcation  of  existing 
geographical  provinces.  Mesozoic  Gastropods  are  too  dissimilar  in  their 
general  characters  to  admit  of  a  close  comparison  with  modern  faunas  ;  but  as 
early  as  the  Eocene  resemblances  to  modern  forms  are  observable,  and  a  certain 
correspondence  is  to  be  noted  with  Gastropods  now  inhabiting  somewhat 
warmer  zones. 

The  Eocene  faunas  of  Europe,  North  America,  Asia  and  Northern  Africa 
share  a  great  many  genera  in  common,  and  have  numerous  others  which  are 
vicarious.  A  very  difFerent  aspect  is  presented  by  the  Eocene  fauna  of 
Australia,  New  Zealand  and  South  America,  where  we  find  the  evident  fore- 
runners  of  forms  now  inhabiting  the  southern  portions  of  the  Atlantic  and 
Pacific  Oceans. 

Still  more  intimate  is  the  relationship  existing  between  the  fossil  land  and 
fresh-water  Gastropods  and  their  descendants  on  the  several  continents.  It 
has  been  observed  that  Miocene  faunas  bear  a  decidedly  tropical  stamp.  On 
this  account  European  and  American  forms  from  the  inland  Miocene  deposits 
bear  some  resemblance  to  the  Recent  faunas  of  the  Azores  and  the  West 
Indies,  as  well  as  to  the  land  and  fresh-water  Gastropods  inhabiting  the  colder 
latitudes  of  Europe  and  Asia.  Only  as  recently  as  the  Pliocene  did  each 
geographical  province  come  to  assume  its  present  distinctive  features. 

In  general,  the  stratigraphic  sequence  of  Gastropod  groups  corresponds 
closely  with  the  zoological  order,  the  most  generalised  forms  appearing  first, 
the  more  specialised  later.  Beginning  with  the  two-gilled  Rhipidoglossa  and 
the  Docoglossa,  f ollowed  by  the  single-gilled  Rhipidoglossa,  Opisthobranchs  and 
taenioglossate  Ctenobranchs,  the  series  leads  to  the  Rachiglossa  in  later  Mesozoic, 


CLASS  V  CEPHALOPODA  583 

and  culminates  in  the  great  increase  of  rachiglossate  and  toxoglossate  families 
in  Tertiary  and  Recent  times.     (See  tables,  pp.  580,  581.) 

[The  text  for  the  preceding  chapter  on  Gastropoda  was  revised  for  the  first  edition  of 
this  work  by  Professor  Henry  A.  Pilsbry,  of  the  Philadelphia  Academy  of  Natural  Sciences, 
and  is  reprinted  here  with  some  slight  changes  at  the  hands  of  Drs.  W.  H.  Dali  and 
R.  S.  Bassler. — Editor,  1 


Olassö.    0EPHALOPODA.1 

Head  sharphj  defined  in  Recent  forms,  except  Nautilus.     Foot  transformed  into  a 

^  Literature  :  Angelin,  N.  P.,  Fragmenta  Silurica,  edited  by  G.  Lindströin.  Stockholm,  1880. 
— A7ithula,  J.,iiJhev  die  Kreidefossilien  des  Kaukasus.  Beitr.  Pal.  Österreich  -  Ungarns,  etc., 
1899-1900,  vol.  xii. — Arthaber,  G.  von,  Die  Cephalopodenfauna  der  Reifliuger  Kalke.  Beitr. 
Paläont.  Geol.  Österreich  -  Ungarns,  etc.,  1896,  vol.  x. — Idem,  Das  Jüngere  Paläozoicum  aus.  der 
Araxes-Enge  bei  Djulfa.  Beitr.  Pal.  Geol.  Österreich -Ungarns,  1900,  vol.  xii. — Idem,  Die  Trias 
von  Albanien.  Ibid.,  1911,  vol.  xxiv.  —Barrande,  «/.,  Systeme  Sibirien  de  la  Boheme,  vol.  ii.,  Cepha- 
lopodes.  Prague,  1867-77. — Bayle,  E.,  and  Zeiller,  R.,  Explication  de  la  carte  geologique  de  France, 
vol.  iv.,  Atlas.  Paris,  1878. — Beecher,  C.  JE.  Ou  the  Development  of  the  Shell  in  Tornoceras. 
Amer,  Journ.  Sei.  [3],  vol.  xl.,  1890. — Benecke,  E.  W.,  Lebensweise  des  Ammoniten.  Abhandl. 
Spezialkarte  von  Elsass-Lothringen,  N.F.,  1905,  Heft  vi. — Bülings,  E.,  Palaeozoic  Fossils.  Geol. 
Surv.  Canada,  1865. — Blake,  J.  F.,  Monograph  of  the  British  Fossil  Cephalopoda,  pt.  i.  London, 
1882.  —  Böhm,  G.,  Beiträge  zur  Geologie  von  Niederländisch  -  Indien.  Palaeontogr.,  1904-7, 
Supplem.  vol.  iv. — Bonarelli'G.,  Osservazioni  sul  Toarciano  d' Aleniano.  Boll.  Soc.  Geol.  Italiana, 
vol.  xii,,  1893. — Boule,  M.,  Lemoine  P.,  and  Thevenin,  A.,  Cephalopodes  cretaces  des  environs  de 
Diego-Suarez.  Ann.  de  Paleontol.,  1906-7,  vol.  i, — Branco,  W.,  Beiträge  zur  Entwickelungsge- 
schichte  der  fossilen  Cephalopoden.  Palaeontogr.,  Bd.  xxvi.,  xxvii.,  1880-81. — Brown,  A.  P.,  On 
the  Young  of  Baculites  compressus.  Proc.  Acad.  Nat.  Sei.  Philad.,  1891-92. — Buch,  L.  von. 
Über  Goniatiten,  Clymenien,  Ceratiten,  etc.  Abhandl.  Berlin.  Akad.  1830, 1838,  1848. — Buckman, 
S.  S.,  Monograph  of  the  Inferior  Oolite  Ammonites.  Palaeont.  Soc,  1887-1900. — Burckhardt,  C, 
Beitr.  zur  Kennt.  Jura  und  Kreideformation  der  Kordilleren.  Palaeontogr.,  1903,  vol.  1. — Idem, 
La  Faune  jurassique  de  Mazapil.    Boletin  de  l'Inst.  geol.  de  Mexique.     No.  23,  1906. 

Canavari,  M. ,  Sui  fossili  del  Lias  inferiore  nell'  Appenino  centrale.  Atti  Soc.  Toscano,  vol.  iv., 
1879. — La  Fauna  degli  strati  con  Aspidoceras  acanthicum  di  Monte  Serra.  Palaeont.  Italica,  vol.  ii., 
1897. — öhoffat,  P.,  Recueil  d'etudes  paleontologiques  sur  la  faune  cretacique  du  Portugal.  Travaux 
geol.  du  Portugal,  1886-1902. — Dacciue,  E.,  Beiträge  zur  Geol,  des  Somalilandes  II.  Ob.  Jura. 
Beitr.  Pal.  Geol.  Österreich-Ungarns,  etc.,  1905,  vol.  xvii.  Dogger  und  Malm  aus  Ostafrika.  Ibid., 
1910,  vol.  xxiii. — Clarke,  J.  M.,  The  Protoconch of  Orthoceras.  Amer.  Geol.,  vol.  xii.,  1893. — Nanno, 
a  new  Cephalopodan  type.  Ibid.  xiv.,  1894. — The  Lower  Silurian  Cephalopoda  of  Minnesota. 
Geol.  Minn.,  vol.  iii.  pt.  ii.,  Palaeont.,  1897. — Conrad,  T.  A.,  Observations  on  the  Silurian  and 
Devonian  Systems,  etc.  Journ.  Acad.  Nat.  Sei.  Philad.,  vol.  viii.,  1839-42. — Observations  on 
Recent  and  Fossil  Shells.  Amer.  Journ.  Couch.,  vol.  ii.,  1866. — Deslongchamps,  E.,  Memoire  sur 
les  Teudopsides.  Mem.  Soc.  Linn.  Normandie,  vol.  v.,  1835. — Diener,  C,  Triadische  Cephalopoden- 
faunen  der  ostsibirischen  Küstenprovinz.  Mem.  Com.  Geol.  St.  Petersb.,  vol.  xiv.  No.  3,  1895. 
— Diener,  C,  Palaeont.  Indica,  Himalayan  Fossils.  The  Cephalopoda  of  the  Muschelkalk,  1895. 
—The  Cephalopoda  of  the  Lower  Trias,  1897.— The  Fauna  of  the  Himalayan  Muschelkalk,  1907. 
— Ladinic,  Carnic,  and  Noric  Faunae  of  Spiti,  1908. — Fauna  of  the  Tropites. — Limestone  of 
Byans,  1906. — Upper  Triassic  and  Liassic  Faunae  of  the  Exotic  Blocks  of  Malla-Johar,  etc.,  1908. 
— Diener,  C,  and  Kraft,  A.  v.,  Palaeontol.  Indica,  Lower  Triassic  Cephalopoda  from  Spiti,  Malla- 
Johar  and  Byans.  Ibid.,  1909,  vol.  vi. — Douville,  IL,  Sur  quelques  fossiles  de  la  zone  ä  Ammonites 
sowerbyi.  Bull.  Soc.  Geol.  France  [3],  vol.  xiii.,  1884-85.— Sur  la  Classification  des  Ceratites  de 
la  Craie.  Ibid.,  1890,  vol.  xviii.— Etüde  sur  les  ammonites  oxfordiennes  de  Villers-sur-mer. 
Mem.  Soc.  Geol.  France,  1912.— Dwight,  W.  JB.,  Recent  Explorations  in  the  Wappinger  Valley 
Limestone.  Amer.  Journ.  Sei.  [3],  1884,  vol.  xxvii.— Favre,  F.,  Die  Ammonitiden  der  unt.  Kreide 
Patagoniens.     N.  Jahrb.  f.  Min.,  1908,  Supplem.  vol.  xxv. 

Foord,  A.  H.,  Catalogue  of  the  Fossil  Cephalopoda  in  the  British  Museum,  pt.  i.,  1888  ;  ii., 
1891  ;  iii.  (Foord  and  Crick),  1%%!.— Frech,  F.,  Lethaea  Geognostica,  I.  Teil.  Lethaea  Palaeozoica, 
Bd.  ii.  Lief.  1.  Stuttgart,  1897.— Über  devonische  Ammoneen.  Beitr.  Pal.  und  Geol.  Österreich- 
Ungarns,  etc.,  1902,  vol.  xiv.— Neue  Cephaloi)oden  aus  den  Buchensteiner,  Wengener,  und  Raibler 
Schichten  des  südlichen  Bakony.  Res.  Wiss.  Erf.  Balatonsees,  1903,  vol.  i.—Fncini,  A.,  La  Fauna 
del  Lias  medio  del  Monte  Calvi.  Palaeont.  Italica,  vol.  ii.,  1897.— Ammoniti  del  Lias  medio 
deir  Appenino  centrale.  Pal.  Ital.,  1899,  vol.  v.  — Cephalopodi  liassici  del  Monte  di  Cetona.  /6w/., 
1901,  vol.  vü.—Gabb,  W.  M.,  and  Meek,  F.  B.,  Geol.  Surv.  California.  Palaeontology,  vols.  i.,  ii., 
l^Qi-Q'd.—Gemmellaro,  G.  G.,  La  Fauna  dei  calcari  con  Fusulina,     Palermo,  1887-89.— I  Cefalopodi 


584  MOLLUSCA  phylum  vi 

funnel-shaped  muscular  swimming-organ ;    mouth  provided  with  jaws  and  radula. 

del  Trias  superiore  della  regione  occidentale  della  Sicilia.  Giorn.  Soc.  Sei.  Nat.  Palermo,  1904, 
vol.  xxiv. — Grandjean,  F.,  Le  Siphon  des  Aramonites  et  des  Beleinnites.  Bull.  Soc.  Geol.  France, 
1910,  vol.  x.—Griesbach,  C.  L.,  Palaeontological  Notes  on  the  Lower  Trias  of  the  Himalayas. 
Records  Geol.  Surv.  India,  vols.  xiii.,  xiv.,  1880-81. — Orossouore,  A.,  Les  Animonites  de  la  Craie 
superieure  de  la  France.  Explic,  Carte  Geol.  France,  1893. — Gümbel,  C.  W.,  Ueber  die  baierisclien 
Alpen.  Verhandl.  Geol.  Reichsanst.  Wien,  Bd.  xii.,  1861-62. — Revision  der  Goniatiten  des 
Fichtelgebirges,  Neues  Jahrb.,  1862. — Ueber  Clymenien  in  den  Uebergangsgebilden  des  Fichtel- 
gebirges. Palaeontogr.,  Bd.  xi.,  1863-64. — Hall,  J.,  Palaeontology  of  New  York,  vols.  i.-iii.,  v., 
Albany,  1847-79. — Rauer,  F,  v..  Die  Cephalopoden  des  Salzkammergutes  und  des  Muschelmarmors. 
Wien,  1846. — Neue  Cephalopoden  von  Hallstadt  und  Aussee.  Haidinger's  Wissen.  Abhandl., 
vols.  i.-iii.,  1847-50. — Beiträge  zur  Kenntniss  der  Cephalopodeufauna  der  Hallstädter  Schichten. 
Denkschr.  Akad.  Wiss.  Wien,  Bd.  ix.,  1855. — Nachträge,  Sitzungsber.,  Bd.  xli.,  1860. — Choristo- 
ceras,  etc.  Jbid.  Bd.  lii.,  1866. — Die  Cephalopoden  des  bosnischen  Muschelkalkes.  Denkschr. 
Akad.  Wiss.  Wien,  vols.  liv.,  lix.,  1888-92. — Hang,  F.,  Beiträge  zu  einer  Monographie  der 
Ammoniten-Gattung  Harpoceras.  Neues  Jahrb.  Beilage  Bd.  iii.,  1885.— Über  die  Polymorphidae, 
etc.  Ibid.  Bd.  ii.,  1887. — Hoernes,  R.,  Zur  Ontogenie  und  Phylogenie  der  Cephalopoden.  Jahrb. 
Geol.  Reichsanst.,  1903,  vol.  liii. — Holm,  G.,  Ueber  die  innere  Organisation  einiger  silurischer 
Cephalopoden.  Palaeont.  Abhandl.  Bd.  iii.,  1885. — Tvenne  Gyroceras -formigt  böjda  Endoceras- 
Arter.  Geol.  Foren.  Stockholm  Förhandl.,  Bd.  xiv.  Hefte  2,  3,  1892. — Om  de  endosifonala 
bildningarna  hos  familien  Endoceratidae.  Ibid.  xvii.  Heft  6, 1895. — Om  apikaläuden  hos  Endoceras. 
Ibid.  vols.  xviii.,  xix.,  1896-97. — Holzapfel,  F.,  Die  Cephalopoden-führenden  Kalke  des  unteren 
Carbon.  Palaeont.  Abhandl.  Bd.  v.  Heft  1,  1889. — Die  Cephalopoden  des  Domanik.  Mnm.  Com. 
Geol.  St.  Petersbourg,  1899,  vol.  xii. — Huxley,  T.  IL,  Structure  of  Belemnites.  Mem.  Geol.  Surv. 
United  Kingdom,  Monogr.  ii.,  1864. — Hyatt,  A.,  The  Fossil  Cephalopods  of  the  Museum  of  Com- 
parative  Zoology.  Bull.  M.  C.  Z.,  vol.  i.,  1868. — Remarks  on  Agassiceras  and  Oxynoticeras. 
Proc.  Boston  Soc.  Nat.  Hist.,  vol.  xvii.,  1875. — The  Jurassic  and  Cretaceous  Ammonites  collected 
in  South  America.  Ibid.  xvii.,  1875. — Genera  of  Fossil  Cephalopods.  Ibid.  xxii.,  1884. — The 
Genesis  of  the  Arietidae.  Smithson.  Miscell.  Collect.,  No.  673,  and  Memoirs  M.  C.  Z.,  vol.  xvi., 
1889. — Carboniferous  Cephalopoda.  I.,  2nd  Ann.  Rep.  Geol.  Surv.  Texas,  1890;  II.  4th  Ann, 
Rep.,  1892. — Pliylogeny  of  an  Acquired  Characteristic.  Proc.  Amer.  Philos.  Soc.  vol.  xxxii.  No. 
143,  1894. — Remarks  on  the  Genus  Nanno.  Amer.  Geol.,  vol.  xvi.,  1895. — Pseudoceratites  of  the 
Cretaceous.  Mon.  xliv.,  U.S.  Geol.  Survey,  1903. — Hyatt,  ^.,  and  Smith,  J.  P.,  Triassic  Cephalopod 
Genera  of  America.  Prof.  Papers,  No.  xl.,  U.S.  Geol.  Survey,  1905. — Karakasch,  N.  J.,  Le  Cretace 
Inferieure  de  la  Crimen  et  sa  faune.     Trav.  Soc.  Imper.  Nat.,  St.  Petersburg,  1907,  vol.  xxxii. 

Karpinsky,  A.,  Über  die  Ammoneen  der  Artinsk  -  Stufe,  etc.  Mem,  Acad.  Sei.  Imp.  St. 
Petersb.  [7],  vol.  xxxvii.,  No.  2,  1889. — Kilian,  W.,  Sur  quelques  fossiles  du  Cretace  inferieur  de 
la  Provence.  Bull.  Soc.  Geol.  France,  vol.  xiii.,  1888.— Äi7<Z,  F.,  Die  Cephalopoden  der  oberen 
Werfenerschichten  von  Mu(5  in  Dalmatien,  etc,  Abhandl.  Geol.  Reichsanst.  Wien,  1903,  vol.  xx. 
— Koenen,  A.  v..  Die  Ammonitiden  des  Norddeutschen  Neokom,  Abhandl.  Preuss.  Geol.  Landesan- 
stalt, 1902,  Heft  24. — Ko7iinch,  L.  G.  de,  Faune  du  calcaire  carbonifere  de  la  Belgique,  pt.  ii., 
Cephalopodes.  Ann.  Mus.  Nat.  Hist.  Bruxelles,  vol.  v.,  1880. — Kossmat,  F.,  Untersuchungen 
über  die  südindische  Kreideformation.  Beitr.  Österreich- Ungarns  und  Orients,  vol.  ix.,  1895.— 
Laube,  G.  (J.,  and  Bruder,  G.,  Ammoniten  der  böhmischen  Kreide.  Palaeontogr.,  Bd.  xxxiii., 
1887. — Lindstrim,  G.,  Ascoceratidae  and  Lituitidae  of  the  Upper  Silurian  Formation  of  Gotland. 
K.  Svensk.  Vetensk.  Akad.  Handling.,  Bd.  xxiii.,  1889.  Philos.  Trans.  1848,  \^h^.~Martelli,  A., 
Cefalopodi  triasici-di  Boljevici  (Montenegro).  Pal.  Ital.,  1907,  vol.  x. — Matheron,  P.,  Recherches 
paleontologiques  dans  le  midi  de  la  France.  Marseille,  1879-81. — Meek,  F.  B.,  Report  on  the 
Invertebrate  Cretaceous  and  Tertiary  Fossils  of  the  Upper  Missouri  Country.  U.S.  Geol.  Surv. 
Territ.,  vol.  ix.,  1876. — Palaeontology,  U.S,  Geol.  Exploration  40th  Parallel  Surv.,  vol.  iv.pt.  i. 
(with  notes  on  Ammonites  by  A.  Hyatt),  1877. — Meek,  F.  B.,  and  Hayden,  F.  F.,  Palaeontology 
of  the  Upper  Missouri.  Smithsonian  Contrib.  Knowl.  vol.  xiv.,  1866.— Meneghini,  G.,  Monographie 
des  fossiles  du  calcaire  rouge  ammonitique  (Lias  superieur)  de  Lombardie.  Paleont.  Lombardie. 
Milan,  1867-81. — Mojsisovics,  F.  v.,  Das  Gebirge  um  Hallstadt.  Abhandl.  Geol.  Reichsanst. 
Wien,  Bd.  vi.,  1873-75,  suppl.  Heft,  1902  ;  pt.  iL,  ibid.,  1893.— Die  Cephalopoden  der  mediter- 
ranen Triasprovinz.  Ibid.  Bd.  x.,  1882. — Über  einige  arktische  Trias  Ammoniten  des  nördlichen 
Sibirien.  Mem,  Acad.  Imp.  Sei.  St.  Petersb.  (7),  vol.  xxxvi.  no.  5,  1888. — Beiträge  zur  Kenntniss 
der  obertriadischen  Cephalopoden-Faunen  des  Himalaya.  Denkschr.  Akad.  Wiss.  Wien,  Bd.  Ixiii., 
1896. — Münster,  G.  von,  Beiträge  zur  Petrefactenkunde,  i.-viii.,  1839-46. — Ueber  die  Clymenien  und 
Goniatiten  im  Uebergangskalk  des  Fichtelgebirges.     Bayreuth,  1843. 

Neumayr,  M.,  Jurastudien.  Jahrl).  Geol.  Reichsanst.  Wien,  Bd,  xxi.,  1871.— Die  Cephalo- 
poden-Fauna  der  Oolithe  von  Baiin  bei  Krakau.  Abh.  Geol.  Reichsanst.  Wien,  Bd,  v.,  1871-73. 
— Die  Fauna  der  Schichten  mit  Aspidoceras  acanthicum,  etc.  Verhandl.  Geol.  Reichsanst,  Wien, 
1874. — Ueber  Kreideammoniten.  Sitzungsber.  Akad.  Wiss.  Wien,  Bd.  Ixxi.,  1875  ;  also  in  Zeitschr. 
Deutsch.   Geol.  Ges.,   Bd.   xxvii.,  1875. — Ueber  unvermittelt  auftreteufle  Cephalopodentypen  im 


CLAss  V  CEPHALOPODA  585 

Sexes  separate.     Sensory  organs  highly  developed.     A  circle  of  fleshy  arms  or  ten- 


Jura  Mittel-Europa's.  Jalirb.  Geol.  Reichsanst.  Wien,  Bd.  xxviii.,  1878. — Zur  Kenntniss  der 
Fauna  des  untersten  Lias  in  den  Nordalpen.  Abhandl.  Geol.  Reichsanst.  Wien,  B<1.  vii.  Heft  5, 
1874-82. — Newnayr^  M.,  and  Uklig,  F.,  Ueber  Ammonitiden  aus  den  Hilsbildungen  Nord- 
deutschlands. Palaeontogr.,  Bd.  xxvii.,  1881. — Nickles,  R.,  Contributions  ä  la  paleontologie  du 
Sud-Est  de  l'Espagne.  Mem.  Soc.  Geol.  France,  No.  4,  1890. — Niküin,  S.  N.,  Der  Jura  der 
Umgegend  von  Elatma,  Nouv.  Mem.  Soc.  Imp.  Moscou,  vols.  xiv.,  xv.,  1879-89. — Allgemeine 
geologische  Karte  von  Russland,  Blatt  56.  Mem.  Com.  Geol.  St.  Petersb.,  vol.  i.,  No.  2,  1884. 
— Die  Cephalopodenfauua  der  Jurabildungen  des  Gouvernements  Kostroma.  Verhandl.  Russ. 
Mineral.  Gesellsch,  [2],  vol.  xx.  1885. — Noelling,  F.,  Cambrische  und  silurische  Geschiebe  Ost- 
und  West  -  Preussens.  Jahrb.  preuss.  geol.  Landesanst.  und  Bergsakad.,  1882, — Beitrag  zur 
Kenntniss  der  Cephalopoden  des  Provinz  Ost-Preussens.  Ibid.  1883;  also  Zeitschr.  Deutsch.  Geol. 
Gesellsch.,  Bd.  xxxiv.,  1882.  —  Fauna  of  Neocomian  Belemnite  Beds.  Palaeont.  Indica,  Ser. 
xvi.,  i.,  pts.  2,  3,  1897. — Untersuchungen  über  den  Bau  der  Lobenlinie  von  Fseudosayeceras  rmclti- 
lobatum  Noetling.  Palaeontographica,  1905,  vol.  li. — Oppel,  A.,  Palaeontologische  Mittheilungen 
aus  dem  Museum  des  baierischen  Staates.  Stuttgart,  1860-65. — d'Orbigny,  A.,  Paleontologie 
fraufaise,  terrain  cretace.  I.  Cephalopodes,  1840 ;  Terrain  jurassique,  Cephalopodes,  1852. 
— Prodrome  de  Paleontologie  Stratigraphique.  Paris,  1850-53. — Parona,  C.  F.,  Nuove  osser- 
vazioni  sopra  la  fauna  con  Posidonomya  alpina,  etc.  Palaeontogr.  Italica,  vol.  i.,  1896. — Fossili 
albiani  d'  Escragnolles,  del  Nizzardo,  etc.  Ibid.  ii.,  1897. — Paulke,  W.,  Die  Cephalopoden  der  ob. 
Kreide  Südpatagoniens.  Ber.  Naturforsch.  Gesell.  Freiburg,  1905,  vol.  xv. — Pervinquiere,  L. ,  Etudes 
de  paleontologie  Tunisienne,  I.  Cephalopodes  des  terrains  secondaires.  Carte  geol.  de  la  Tunisie, 
1907. — Philipjri,  E.,  Die  Ceratiten  des  oberen  deutschen  Muschelkalkes.  Pal.  Abhandl.  N.F.,  1901, 
vol.  iv. — Phillips,  J.,  Illustrations  of  the  Geology  of  Yorkshire,  pt.  ii.  London,  1836. — Figures  and 
Descriptions  of  the  Palaeozoic  Fossils  of  Cornwall,  Devon,  etc.  London,  1841. — Pictet,  F.  J., 
and  Campiche,  G.,  Description  des  fossiles  du  terrain  cretace  des  environs  de  Ste.  Croix.  Geneva, 
1858-72. — Pompeckj,  J.  F.,  Beiträge  zu  einer  Revision  der  Ammoniten  des  schwäbischen  Jura,  Lief, 
i.,  ii.  Stuttgart,  1893-96. — Über  Animonoideen  mit  "anormaler"  Wohnkammer.  Jahreshefte 
Vaterl.  Naturk.  Wilrttemb.,  1894. — Ammoniten  des  Rhät.     Neues  Jahrb.,  Bd.  ii.,  1895. 

Quenstedt,  F.  A.,  Ueber  die  vorzüglichsten  Kennzeichnen  der  Nautileen.  Neues  Jahrb., 
1840. — Petrefactenkunde  Deutschlands,  I.  Cephalopoden.  Tübingen,  1849. — Der  Jura.  Tübingen, 
1858. — Die  Ammoniten  des  schwäbischen  Jura,  Bd.  i.-iii.  Stuttgart,  1885-88. — Remele,  A., 
Zur  Gattung  Palaeonautilus.  Zeitschr.  Deutsch.  Geol.  Gesellsch.,  Bd.  xxiii.,  1881. — Renz,  C, 
Die  mesozoischen  Faunen  Griechenlands.  I.  Die  triadischen  Faunen  der  Argolis.  Palaeontogr., 
1911,  vol.  Iviii. — Reynes,  P.,  Monographie  des  Ammonites.  (Text  incomplete),  1879. — Roemer, 
F.  V.,  Lethaea  Geognostica.  I.  Lethaea  Palaeontologica.  Stuttgart,  1880-83. — Das  rheinische 
Uebergangsgebirge.  Hannover,  1844. — Riidemann,  R.,  Structure  of  some  primitive  Cephalopods. 
Report  N.Y.  State  Paleontologist,  1904. — Sandberger,  G.,  Beobachtungen  über  die  Organisation 
der  Goniatiten.  Jahrb.  Ver.  NatUrk.  Nassau,  Bd.  vii.  p.  292,  1851. — Sandberger,  G.  and  F.,  Die 
Versteinerungen  des  rheinischen  Schichtensystems  in  Nassau.  Wiesbaden,  1850-55. — Schlüter, 
(!.,  Cephalopoden  der  oberen  deutschen  Kreide.  Palaeontogr.,  Bd.  xxi.,  xxiv.,  1872-77. — Schröder, 
II.,  Untersuchungen  über  silurische  Cephalopoden.  Palaeont.  Abhandl.,  Bd.  v.  Heft  4,  1891. — 
Siemiradzki,  J.,  Monograph.  Beschreib,  der  Ammonitengattung  Perisphinctes.  Palaeontogr.,  1899, 
vol.  xliv. — Smith,  J.  F.,  Comparative  Study  of  Palaeontology  and  Phylogeny.  Journ.  Geol., 
vol.  V.  No.  5,  1897. — Marine  Fossils  of  the  Coal  Measures  of  Arkansas.  Proc.  Amer.  Philos.  Soc. 
vol.  xxxv.,  1897. — The  Development  of  Glyphioceras,  etc.  Proc.  Calif.  Acad.  Sei.  [3],  vol.  i., 
1897. — Tlie  Carboniferous  Ammonoids  of  America.  Mon.  xlii.,  U.S.  Geol.  Survey,  1903. — Siein- 
maun,  G.,  Ueber  Tithon  und  Kreide  in  den  peruanischen  Anden.  Neues  Jahrb.,  Bd.  ii.,  1881. 
—Stauton,  T.  W.,  The  Colorado  Formation.  Bull.  U.S.  Geol.  Surv.  No.  106,  \%^Z.—Stoliczka, 
F.,  and  Blanford,  H.  F.,  Fossil  Cephalopoda  of  the  Cretaceous  Rocks  of  Southern  India. — Mem. 
Geol.  Surv.  India,  Palaeont.. Indica,  1861-66.— Äwe^s,  F.,  Ueber  Ammoniten.  Sitzungsber.  Akad. 
Wiss.  Wien,  Bd.  lii.,  Ixi.,  1866-70.— TtY^,  A.,  Die  fossilen  Cephalopodengebisse.  Jahrb.  Geol. 
Reichsanst.  Wien,  1907,  vol.  liv. — Tornquist,  A.,  Die  degenerierten  Perisphinctiden  des  Kimmeridge 
von  Le  Havre.  Abhandl.  Schweizer.  Pal.  Gesellsch.,  Bd.  xxiii.,  1896.— Tot^a,  F.,  Eine  Muschelkalk- 
fauna  am  Golfe  von  Ismid  in  Kleinasien.  Beitr.  Paläont.  Geol.  Österreich -Ungarns  u.  Orients, 
Bd.  X.,  1896. —  Uhlig,  F.,  Die  Cephalopodenfauua  der  Wernsdörfer  Schichten.  Denkschr.  Akad. 
Wiss.  Wien,  Bd.  xlvi.,  and  Sitzungsl)er.  Bd.  Ixxxvi.,  1883. — Über  die  Cephalopodenfauua  der 
Teschener  und  Grodischter  Schichten.  Denkschr.  Akad.  Wiss.  Wien,  1901,  vol.  Ixxii.— The 
Fauna  of  the  SpUi  shales.  Pal.  Indica,  ser.  xv.,  1910,  vol.  iv.  —  Waageii,  TF.,  The  Jurassic  Fauna 
of  Kutch,  vol.  i.  Cephalopoda.  Palaeont.  Indica,  ser.  ix.,  1873-76.— Salt  Range  Fossils.  I. 
Productus  Limestone  Fossils  ;  Cephalopoda.  Ibid.  ser.  xiii.,  1879-88.  II.  Fossils  froni  the 
Ceratite  Formation.  Ibid.  ser.  xiii.,  1895.— Wähner,  F.,  Beiträge  zur  Kenntniss  der  tieferen 
Zonen  des  unteren  Lias  der  nordöstlichen  Alpen.  Beitr.  Paläont.  Geol.  Österreich-Ungarns  u. 
Orients,  Bd.  ii.,  ix.,  1882-95.  — Wag^ier,  A.,  Fossile  Überreste  von  nackten  Tintenfischen.  Abh. 
Bayer.    Akad.    Wiss.,    Bd.   viii.,   1856-60. —  Wedekind,  R.,   Die  Cephalopotlenfauna  des  höheren 


586  MOLLUSCA  phylum  vi 

tades  Surround  the  moufh,  and  serve  as  prehensile  and  locomotive  organs ;  in  the 
Dibranchiates  tliey  are  armed  with  hooJcs  and  sucker s.^ 

The  Cephalopods  are  the  most  highly  organised,  and  include  the  largest- 
sized  of  all  known  Mollusca.  They  breathe  by  gills,  and  are  exclusively  marine. 
Their  nervous,  circulatory,  digestiye  and  reproductive  Systems,  their  muscula- 
ture  and  sense  organs  all  exhibit  remarkable  differentiation  as  compared  with 
those  of  other  Mollusks.  A  fleshy  mantle,  which  is  open  above,  encloses  the 
cavity  which  is  occupied  by  the  respiratory  organs  (the  gills)  and  it  also 
serves  as  a  covering  for  the  reproductive,  alimentary  and  secretory  Systems, 
the  heart  and  the  principal  blood-vessels.  A  large  ganglionic  mass  (cerebral 
ganglion)  and  sub-oesophageal  ganglion  connected  by  commissures  are  placed 
around  the  Oesophagus,  and  are  surrounded  by  a  cartilaginous  enclosure  in  the 
Dibranchiates,  but  in  Nautilus  this  protects  only  the  sub-oesophageal  nerve  mass. 

Eecent  Cephalopods  were  divided  by  Owen  into  two  groups — Tetrahranchiata 
and  Dibranchiata.  The  former  is  represented  in  the  present  fauna  by  the  soli- 
tary  genus  Nautilus,  but  the  latter  still  comprises  a  very  considerable  series  of 
forms.  A  host  of  fossil  Cephalopods  abounded  in  the  Paleozoic  and  Mesozoic 
seas.  Among  these  the  two  largest  groups,  the  Ammonoidea  and  Belemnoidea,  do 
not  afford  any  certain  information  regarding  the  number  of  gills,  but  the  shells 
of  the  former  agree  essentially  with  those  of  Nautili,  while  those  of  Belemnites, 
on  the  other  band,  are  more  like  those  of  certain  Dibranchiates ;  hence  it  is 
advisable  to  associate  these  fossil  groups  with  the  corresponding  sub-classes 
established  for  Eecent  forms. 

Subclass  1.  TETRABRANCHIATA  Owen.' 

Cephalopods  with  four  plumose  gillSj  and  external  chambered  shells.      Amhula- 

Oberdevon  am  Enkeberg.  Neues  Jahrb.  f.  Min.  etc.,  1908,  Supplem.  vol.  xxvi.  —  White,  C.  A., 
Mesozoic  Fossils.  Bull.  U.S.  Geol.  Surv.  No.  4,  ISSA.—Whüeaves,  J.  F.,  Mesozoic  Fossils, 
vol.  i.  Geol.  Surv.  Canada,  1876-79. — Palaeozoic  Fossils,  vol.  iii.,  ibid.  1884-97. — Contributions 
to  Canadian  Palaeontology,  vol.  i.,  1885-89. — Descriptions  of  Fossils  from  the  Devonian  of  Manitoba. 
Trans.  Roy.  Soc.  Canada,  vol.  viii.  sec.  4,  1890.  —  Whitßeld,  R.  P.,  Several  papers  in  Bull.  Amer. 
Mus.  Nat.  Hist.,  1886-97.— Eepublication  of  Hall's  Fossils,  etc.  Ibid.  vol.  i.,  pt.  ii.,  1895. 
Wright,  T.,  Monograph  on  the  Lias  Ammouites.  Palaeont.  Soc,  1878-86. —  Würtenberger,  R., 
Studien  über  die  Stammgeschichte  der  Ammoniten.  Darwinistische  Schriften,  No.  5.  Leipzic, 
1880.  —  Vabe,  H.,  Cretaceous  Cephalopoda  from  the  Hokkaido.  Journ.  Coli.  Sei.  Iniper.  Univ. 
Tokyo,  Japan,  1904,  vols.  xix.,  xx. — Zittel,  K.  A.,  Cephalopoden  der  Stramberger  Schichten. 
Palaeont.  Mittheil.  Museum  Bayer.  Staates,  Bd.  ii.,  1868. — Die  Fauna  der  älteren  Tithonbildungen. 
Ibid.  Bd.  iii.,  1870.— Handbuch  der  Paläontologie,  Bd.  iL,  1881-85. 

^  A.  E.  Verrill  has  furnished  the  following  note  regarding  the  arms  of  Cephalopods  :  "  The 
arms,  together  with  the  siphon  (ambulatory  funnel)  of  Cephalopods,  must  be  considered  as 
homologous  with  the  foot  of  other  Mollusca.  The  large  nerves  supplying  these  organs  arise  from 
the  pedal  ganglia.  In  the  early  larval  stages  the  arms  arise  as  bud-like,  paired  lateral  outgrowths 
at  the  base  of  the  large  yolk-sac,  while  the  rudiments  of  the  siphon  (fxmnel)  arise  as  two  oblique 
pairs  of  folds  situated  farther  back.  The  anterior  pair  of  these  folds  eventnally  unite  and  form 
the  central  or  tubulär  part  of  the  siphon,  and  the  more  posterior  folds  form  the  lateral  or  valvulär 
portions  of  the  same  organ.  The  rudimentary  arms  arise  posterior  to  the  mouth  on  the  ventral 
and  lateral  sides  of  the  yolk-sac,  and  only  Surround  the  buccal  region  at  a  later  stage.  The 
yolk-sac  occupies  the  same  relative  position,  behind  the  mouth,  as  the  central  part  of  the  foot- 
area  of  ordinary  Gastropod  larvae  in  the  early  veliger  stages.  Therefore  the  arms  are  muscular, 
lateral  outgrowths  of  this  same  foot-area.  The  two  lateral  rows  of  rudimentary  arms  are  widely 
separated  at  first  by  the  yolk,  but  during  the  absorption  of  this,  they  rapidly  approach  each  other 
and  converge  around  the  mouth." 

2  Owen,  R.,  Memoir  on  the  Pearly  Nautilus.  London,  1832,  —  Kerr,  J.  O.,  Anatomy  of 
Nautilus  pompilius.  Proc.  Zool.  Soc,  London,  1895. — Griffin,  L.  E. ,  Anatomy  of  Nautilus 
pompilius.     Mem,  Nat.  Acad.  Sei.,  1900,  vol.  viii. 


CLASS  V 


CEPHALOPODA 


.87 


tory  funnel  divided  ;  ink-lag  ahsent ;  arms  represented  in  existing  Nauüli  by  lobes 
and  numerous  tentades,  which  are  without  hooks  and  suckers.  Cambrian  to 
Recent. 


Fig.  1098. 


Nautilus  2^ompilius  Linn. 


Our  knowledge  of  the  soft  parts  of  the  Tetrabranchiates  is  based  entirely 
upon  the  single  existing  genus  Nautilus  (Fig.  1098).  The  soft  parts  are  con- 
tained  in  the  outer- 
most  compartment 
(living  Chamber)  of 
the  Shell,  the  ventral 
portions  being  on 
the  external  side. 
The  body  is  short 
and  thick,  and  the 
head  separated  from 
the  remaining  por- 
tion.  Around  the 
mouth  are  about 
ninety  external  fili- 
form tentacles, 
placed  upon  the 
edges  of  lobes,  and 
their  basal  parts 
when  contracted  are 
lodged  in  fleshy 
sockets  or  sheaths. 
The  pair  of  tentacles 
on  the  inner  or 
dorsal  side  are  fused  so  as  to  form  a  thicker  muscular  lobe  or  hood,  which 
serves  to  close  the  aperture  of  the  shell  when  the  animal  is  withdrawn  into 
the  living  chamber.  On  the  ventral  side  of  the  head  and  tentacles,  but 
separated  from  them,  is  a  very  thick  muscular  leaf,  having  the  free  edges 
external  and  rolled  in  upon  themselves  (Fig.  1098,  d).  This  is  the  so-called 
ambulatory  funnel  of  authors  generally  (hyponome  of  Hyatt),  and  its  cavity 
is  contracted  anteriorly  and  dilated  posteriorly,  where  it  opens  into  the 
branchial  chamber.  It  serves  to  conduct  water  which  is  taken  by  suction 
into,  and  then  violently  expelled  from  the  gill  cavity  of  the  mantle,  thus 
driving  the  creature  backward  by  the  force  of  reaction.  Kerr  suggests  that  the 
structure  of  the  infolding  edges  of  the  hyponome  and  the  muscular  character 
of  this  Organ  would  enable  the  animal  to  unroU  and  flatten  it  out  so  as  to  be 
available  for  crawling.  It  is  supposed  to  be  homologous  with  the  foot  of 
Gastropods,  and  this  Suggestion,  if  true,  would  show  that  it  had  not  entirely 
lost  its  normal  functions  in  primitive  forms  of  Cephalopoda. 

On  either  side  of  the  head,  near  the  pair  of  lateral  tentacles,  is  placed  a 
large  eye  of,  primitive  structure,  which  is  supported  on  a  short  peduncle. 
The  mouth  is  in  the  centre  of  the  lobes  and  grouj^s  of  tentacles,  the  tongue  is 
fleshy,  and  the  radula  armed  with  numerous  rows  of  plates  and  hooks.  The 
reraarkably  powerful  jaws  (Figs.  1099,  1100)  are  largely  composed  of  a  dark 
horny  substance,  only  their  points  being  calcified.  Similar  calcified  beaks  are 
not    uncommon    in    Mesozoic    terranes,  being    found    either  associated   with 


Recent ;  Indian  Ocean.  Shell  with  contained  soft 
parts  Seen  from  the  left  side,  the  shell  being  cut  through  along  the  median 
line.  a,  Mantle ;  b,  Dorsal  lobe  of  the  mantle ;  c,  Hood  ;  d,  Hyponome,  or 
"  ambulatory  funnel "  ;  e,  Nidamental  gland  ;  h,  Muscle  for  attachment;  o,  Eye  ; 
s,  Siphuncle  ;  t,  Tentacles  ;  x,  Septal  Chamber  (after  R.  Owen). 


588 


MOLLUSCA 


PHYLUM  VI 


Nautiloid  shells  or  detached.     The  jaws  belonging  to  Nautilus  hidorsatus  from 
the    Trias    were   originally  described    under    the    name    of   BhynchoUtes   and 


Fig.  1099. 

Upper  jaw  of  Nautilus  pompilius. 
A,  Side  view ;  B,  Inferior  aspect.  i/i. 


Fig.  1100. 

Lower  jaw' of  Nautilus 
pompilius.  Side  view.  i/^. 


Temnocheilus  hidorsatus  Schloth.  (  =  lihyn- 
chnlithes  hirundo  Faure-Biguet).  Muscliel- 
kalk  ;  Laineck,  near  Bayreuth.  A,  Upper 
jaw,  viewed  from  above  ;  B,  from  the  side  ; 
C,  from  below. 


Conchorhynchus  (Figs.  1101,  1102);  the  common  Jurassic  and  Cretaceous 
forms  are  known  as  llkynchoteuthis  (Fig.  1103)  and  Palaeoteuthis  d'Orbigny. 
The  long  feather-like  gills  are  disposed  in  two  pairs  at  the  base  of  the 
hyponome,  and  between  them  is  the  anus,  closely  behind  which  is  placed  the 

A  Single  or  double  orifice 

of   the    generative    Or- 
gans.     In    the   female 
there  is  found   at  the 
base  of  the  gill  cavity 
a     long,     tri- 
partite,    nida- 
mental  gland, 
which      fuses 
ex  t  er  nally 
wi  th       the 
mantle. 

The  body 

s  h  o  r  t, 

sack  -  shaped, 

rounded   pos- 

teriorly,  and  enveloped  by  the  mantle.  The  base  of  the  latter  is  prolonged 
at  a  certain  point  into  a  fleshy,  hollow  cord  or  tube  (the  siphon),  which  passes 
through  a  rounded  aperture  in  each  of  the  septa,  and  extends  as  far  as  the 
inner  side  of  the  apex  in  the  initial  Chamber.  The  fastening  of  the  animal 
within  the  living  Chamber  is  accomplished  by  two  oval  muscles  situated  on 
either  side  near  the  base  of  the  mantle.  These  muscles  are  attached  to  the 
inner  wall  of  the  living  Chamber,  and  have  corresponding  but  very  shallow 
impressions.  They  are  connected  both  dorsally  and  ventrally  by  a  band  of 
fibres,  the  annulus,  which  also  leaves  its  impression  upon  the  shell.  The  form 
and  Position  of  the  muscles  for  attachment  and  the  annulus  are  sometimes 
discernible  on  the  internal  moulds  of  fossil  shells. 

The  shells  of  existing  Nautili  are  coiled  in  one  plane,  and  composed  of 
several  volutions,  the  outermost  of  which  either  envelops  all  the  earlier  ones 
{Nautilus  pompilius),    or   leaves    the   umbilicus  partly  open  (N  umbilicatus). 


Fig.  1102. 

Temnocheilus  hidorsatus  Schlotheim 
{=  Conchorhynchus  avirostris  .Blainville). 
Muschelkalk ;  Laineck,  neap  Bayreuth. 
Lower  jaw  viewed  from  above. 


Ehynchotcuthis  sahaudianus  Pict.  and   Lor. 
Neocomian ;     Voirons,     France.      vi,    Dorsal    ; 
aspect,  showing  in  part  the  chitinous  lateral 
expansions.      B,  The    calcareous    beak    seen 
from  below. 


CLASS  V  CEPHALOPODA  589 

With  the  exceptio!!  of  the  last  half  of  the  outer  volution,  which  is  occupied 
by  the  animal  as  a  living  Chamber,  the  shell  is  divided  up  into  numerous 
cavities  or  Chambers  by  parallel  partitions  called  septa^  the  mesal  parts  of  which 
are  concave  toward  the  aperture ;  and  they  are  disposed  at  regulär  intervals. 
The  compartments  thus  formed  are  said  by  different  authors  to  be  filled 
with  air,  gaseous  or  even  fluid  matter,  and  all  are  traversed  by  the  siphon.^ 

The  siphon  has  dense  walls  and  is  probably  not  capable  of  any  extended 
movements  inside  of  the  surrounding  calcareous  parts  which  form  the  siph- 
uncle.  The  relation  of  the  siphuncle  to  the  septal  Chambers  in  Nautilus  has 
not  been  sufficiently  investigated  to  enable  one  to  State  distinctly  what  its 
functions  may  be.  The  whole  exterior  of  the  mantle  and  siphon  is  encased 
in  a  cuticle  of  horny  matter,  the  remains  of  which  are  often  found  in  the 
living  Chambers  and  siphuncles  of  fossil  forms  as  well.  The  shell  itself  is 
composed  of  two  layers,  an  internal  and  an  external.  The  outer  layer  is 
composed  of  imbricated  laminae,  is  porcellanous,  light-coloured  and  super- 
ficially  ornamented  with  red  or  brown  transverse  bands ;  the  inner  layer  is 
nacreous,  and  composed  of  thin,  parallel  laminae,  which  are  crossed  by  fine 
rectangular  lines.  The  septa  likewise  consist  of  a  pearly  layer,  but  are 
covered  over  like  the  inner  walls  of  the  Chambers  with  a  very  thin,  opaque, 
calcareous  film.  A  large  number  of  fossil  shells  have  a  structure  similar  to 
the  recent  Nautilus.  These  are  divided  into  several  groups,  characterised  by 
peculiarities  of  the  initial  Chamber,  and  by  differences  in  the  suture  lines, 
siphuncles,  sculpturing  and  form  of  the  aperture. 

Our  knowledge  of  the  life-history  of  the  Nautilus  is  very  limited. 
Although  empty  shells  are  cast  ashore  in  great  quantities  in  the  Pacific  and 
Indian  Oceans,  the  animal  is  rarely  found  alive.  According  to  Kumpf,  the 
creature  swims  by  ejecting  water  through  the  hyponome,  and  at  the  same  time 
holds  the  tentacles  expanded  horizontally,  and  the  head  protruded  as  far  as 
possible ;  but  when  creeping,  probably  the  head  and  tentacles  are  directed 
downward.^  The  shell  is  essentially  alike  in  both  cases.  However,  in 
Nautilus  pompiliuSf  Willey  has  found  that  the  f emales  differ  in  having  flatter 
and  more  convergent  sides,  the  males  being  stouter  and  more  gibbous,  which 
is  exactly  contrary  to  the  prevalent  notions  with  regard  to  sex  among  shell- 
bearing  Cephalopods.  The  shell  is  supposed  to  serve  as  a  hydrostatic  apparatus, 
sinking  when  the  animal  withdraws  into  the  living  chamber,  but  sufficiently 
buoyant  to  float  itself  and  the  animal  when  the  head  and  tentacles  are 
protruded  in  the  act  of  swimming.     Moseley  ^  confirms  the  observations  of 

^  These  conditions  are  described  by  Professor  Verrill  in  tlie  following  note  :  ' '  The  pericardium 
of  NmUüus  ponipüms  comniunicates  directly  with  the  gill  cavity  by  special  pores,  which  are  close 
to  the  orifices  of  the  nephridia,  but  do  not  iinite  directly  with  latter,  as  in  most  Mollusca.  Water 
can,  therefore,  pass  directly  into  the  pericardium  and  other  coelomic  cavities.  The  cavity  of  the 
siphuncle  appears  to  communicate  directly  with  the  pericardium,  and  hence  with  the  gill  cavity  by 
means  of  the  special  pores.  Thus  sea-water  can  readily  pass  into  or  out  from  the  Chambers  of  the 
shell,  to  equalise  pressure  at  varying  depths,  as  in  most  marine  Mollusca.  These  Chambers  are 
unquestionably  filled  with  fluid  under  normal  conditions.  But  living  as  the  animal  does  under 
pressure  at  considerable  depths,  the  fluid  in  the  Chambers  is  saturated  with  the  gases  in  Solution. 
When  the  JVautüüs  is  rapidly  brought  to  the  surface,  some  of  the  gas  is  liberated  in  consequence  of 
diminished  pressure,  and  must  occupy  part  of  the  space  within  the  chaml>ers  by  forcing  out  some  of 
the  fluid.  Hence  the  sliell  will  float  until  the  free  gases  within  the  Chambers  are  absorbed  or 
otherwise  eliminated.  There  is  no  evidence  that  free  gases  are  ever  naturally  present  in  the  living 
Chambers  during  life," 

2  Rumphius,  G.  j&. ,  Amboinische  Rariteitkamer,  p.  59.     Amsterdam,  1705. 

3  Moseley  IL  iV.,  Narrative  of  the  Voyage  of  the  Challenger,  vol.  l— Fischer,  P.,  Manuel  de 


590  MOLLUSCA  phylum  vi 

Eumphius,  but  the  animal  he  studied  was  drawn  up  by  a  dredge  which  had 
been  dragged  on  the  bottom  at  a  depth  of  300  fathoms.  This  individual 
swam  in  the  manner  described,  but  was  not  able  to  sink ;  and  this  was 
accounted  for  on  the  supposition  that  in  rising  from  the  bottom  the  sudden 
expansion  and  rarefication  of  the  contents  of  the  air-chambers  had  interfered 
with  the  action  of  the  hydrostatic  apparatus. 

Nothing  has  yet  been  ascertained  regarding  the  mode  of  reproduction 
and  development  of  the  animal  in  Nautilus.  The  construction  of  the  shell 
in  this  genus,  however,  renders  it  probable  that  in  the  youngest  stage  a 
perishable  embryonal  shell  was  formed,  the  presence  of  which  is  indicated  by 
a  scar  or  cicatrix  on  the  apex  of  the  initial  Chamber.  Hyatt  describes  and 
figures  a  more  or  less  wrinkled  lump  on  the  apex  of  several  species  of  the 
Orthoceratidae,  which  he  regards  as  an  embryonal  shell  or  protoconch ;  and 
Clarke  also  figures  one  having  a  nearly  perfect  form.  The  former  explains 
the  absence  of  the  protoconch  in  fossil  genera  and  in  the  Recent  Nautilus  by 
supposing  it  was  usually  membranous  or  imperfectly  calcified,  and  hence 
easily  destroyed. 

As  the  animal  continued  to  grow,  it  advanced  forward  by  building  out 
the  edges  of  the  aperture  and  secreted  new  septa  at  regulär  intervals,  each 
one  probably  corresponding  to  a  period  of  repose.  A  tubulär  Prolongation  of 
the  base  of  the  mantle  was  formed  at  each  period  of  progress,  and  this 
remained  behind  in  the  first  septal  chamber  and  excreted  the  calcareous 
matter  that  built  the  last  segment  of  the  siphuncle.  Each  septum  bends 
apically  into  a  funnel  around  the  origin  of  the  siphon  at  the  base  of  the 
mantle,  and  this  is  continuous  with  a  calcareous  but  more  loosely  constructed 
and  very  porous  wall  that  prolongs  the  tube  begun  by  the  funnel.  This 
porous  wall  or  sheath  coats  the  funnel  on  its  external  surface  in  the  air- 
chambers,  but  it  continues  alone  apically  beyond  the  funnel,  and  is  inserted 
into  the  spreading  trumpet-like  opening  of  the  next  preceding  funnel.  The 
siphuncle  is  therefore  a  segmented,  calcareous  tube  surrounding  the  siphon, 
each  segment  crossing  only  one  septal  chamber  and  consisting  of  a  funnel  and 
its  connecting  sheath.^ 

In  Nautilus  the  margin  of  the  external  opening  or  aperture  is  sinuous,  the 
concavities  being  the  sinuses,  the  outward  convexities  the  crests  ;  and  the 
Single  median  concave  bend  on  the  venter  is  named  the  hyponomic  sinus, 
because  it  indicates  the  position  of  the  hyponome.  In  some  fossil  genera 
(Orthoceras)  the  aperture  is  often  straight  or  simple  (Fig.  1111);  in  others 
the  lateral  margins  are  produced  in  the  form  of  ear-like  crests  or  lappets 
(Lituites,  Ophidioceras) ;  and  in  some  forms  they  approximate  more  or  less, 
forming  contracted  apertures. 

The  closure  of  the  aperture  is  never  complete,  and  may  take  place  through 
the  inward  growth  of  the  lateral  margins,  as  in  Phragmoceras  (Fig.  1136), 
forming  a  direct  dorso-ventral  slit,  or  from  the  venter  and  the  sides,  as  in 
Mandeloceras  (Fig.  1133),  producing  a  T-shaped  opening;  or,  as  in  Hercoceras 
(Fig.  1120),  it  may  occur  principally  from  the  dorsum  and  venter,  resulting  in 

Conchyliologie,  1880-87.-^*7%,  A.,  In  the  Home  of  the  Nautilus.  Natural  Science,  1895, 
vol.  vi. 

1  Brooks,  H.,  On  the  Structure  of  the  Siphon  and  Funpel  in  Nautilus  pompilius.  Proc.  Boston 
Soc.  Nat.  Hist.,  1888,  vol.  xxiii. — AppelUf,  A.,  Die  Schalen  von  Sepia,  Spirula und  Nautilus.  Kön. 
Svensk.  Vetensk.  Akad.  Handling.,  1895,  vol.  xxv.  No.  7. — Grandjean,  F.,  Le  Siphon  des  Ammonites 
et  des  Belemnites.       Bull.  Soc.  Geol.  France,  1910,  vol.  x. 


CLAss  V  CEPHALOPODA  591 

a  transverse  aperture.  The  dorsal  side  of  the  aperture  is,  as  a  rule,  occupied 
by  a  crest,  known  as  the  dorsal  crest  (Figs.  1115,  1121,  1138).  The  position 
of  the  hyponome  is  indicated  by  the  large  single  opening  and  sinus  at  the 
termination  of  the  longer  median  slit  of  the  aperture  in  shells  with  contracted 
openings  that  obviously  had  this  organ  (Phragmoceras,  Gomphoceras,  etc.) ;  but 
in  others  like  Hercoceras,  which  have  no  ventral  sinus  in  the  aperture,  the 
hyponome  was  probably  absent  or  non-functional.  The  sinus  in  the  lines  of 
growth,  however  (Fig.  1120),  show  that  this  organ  was  present  in  the  pre- 
ceding  stages  of  development  before  the  contracted  apertures  were  formed. 

Pompeckj  states  that  contracted  apertures  occur  only  in  senile  stages  of 
growth,  and  small  shells  having  this  peculiarity  must  be  regarded  as  dwarfs. 
This  is  certainly  true  of  many  species,  and  is  probably  also  the  case  with 
Hercoceras  and  the  like.  T-shaped  apertures  often  show  several  accessory 
sinuses  and  crests  (Fig.  1134),  which  probably  indicate  the  number  of  their 
protrusible  arms  or  tentacles.  Most  curved  forms  have  the  ventral  sinus  on 
the  arched  external  side  (exogastric  shells),  but  some  have  it  on  the  concave 
internal  side,  as  in  Phragmoceras,  and  these  are  called  endogastric  shells.  The 
interior  wall  of  the  living  Chamber,  and  volutions  in  recent  and  fossil 
Nautiloids  (Fig.  1122),  are  typically  marked  with  fine  transverse  and  longi- 
tudinal  lines.  In  the  recent  Nautilus  a  black  superficial  layer,  composed  in 
part  of  organic  matter,  is  deposited  by  the  hood  immediately  in  front  of  the 
aperture  on  the  dorsum. 

The  internal  partitions  or  septa,  which  divide  the  volutions  into  Chambers, 
Vary  exceedingly  in  number  among  different  species  and  also  at  diiferent  ages 
of  the  same  individual ;  but  they  are  tolerably  constant  as  a  rule,  within  the 
limits  of  one  and  the  same  species,  if  specimens  of  the  same  age  are  compared. 
They  follow  one  another  in  regulär  succession,  but  as  observed  by  Hyatt,  the 
intervals  are  relatively  greater  in  the  young,  more  constant  in  the  adult,  and 
then  markedly  decrease  in  the  oldest  stages  of  development.  Each  septal 
Chamber  (camera  of  Hyatt)  was  part  of  the  living  Chamber  until  it  was  cut  off 
by  a  septum  and  left  empty  as  the  animal  moved  forward.  Perfectly  pre- 
served  shells  may  have  the  living  Chamber  alone  filled  up  with  stony  matrix, 
since  the  sediment  could  only  pass  into  the  preceding  Chambers  through  the 
siphuncle,  or  as  a  result  of  injury  to  the  walls  of  the  camerae.  Nevertheless, 
these  last  are  seldom  entirely  empty,  their  interiors  being  frequently  lined 
with  crystals  of  infiltrated  calcite,  quartz,  celestine,  baryte,  pyrite,  or  with 
organic  secretions.  Double  septa  occur  in  some  forms  (Actinoceras),  and  in 
others  the  camerae  are  sometimes  secondarily  partitioned  ofF  by  intermediate 
walls  or  pseudo-septa,  which  may  either  run  parallel  with  the  septa  proper,  or 
at  an  angle  with  them,  and  are  composed  of  two  readily  separable  calcareous 
lamellae.  The  origin  of  these  pseudo-septa  has  been  attributed  to  the 
calcification  of  regularly  arched  membranes  at  the  posterior  end  of  the  body. 

The  line  of  junction  between  the  septa  and  inner  wall  of  the  shell  is  called 
the  suture,  This  is  invisible  externally,  except  when  the  shell-substance  has 
been  broken  or  worn,  or  dissolved  away,  and  it  is  seen  most  clearly  on  natural 
moulds.  The  sutures  of  Nautiloid  shells  follow,  as  a  rule,  simple,  straight  or 
slightly  undulating  lines.  These  undulations,  when  convex  toward  the  apex, 
are  termed  lohes,  and  the  reversed  or  forward  curves  are  the  saddles.  They  are 
called  lateral  lohes  when  occurring  on  the  sides,  and  when  on  the  venter  or 
dorsum  are  termed  ventral  or  dorsal  lohes  and  saddles.     The  annular  lohe  is  a 


592  MOLLUSCA  phylum  vi 

small  median  dorsal  lobe,  usually  pointed  and  occupying  the  centre  of  the 
main  dorsal  lobe.  It  is  supposed  to  have  had  some  relation  to  the  correspond- 
ing  inflection  or  point  of  the  annular  muscle  among  the  Nautiloidea.  In  more 
specialised  shells  it  is  associated  with  a  conical  inflection  of  the  septum  itself. 
The  curves  are  undulatory  as  a  rule,  but  in  some  genera  may  be  more  or  less 
angular. 

The  Position  of  the  siphuncle  does  not  enable  one  to  determine  which  is 
the  ventral  and  which  the  dorsal  side  in  most  genera,  but  the  hyponomic  sinus 
in  the  aperture  and  the  curved  lines  of  growth  are  an  almost  unfailing  index 
of  the  ventral  side.  The  siphuncle  is  apt  to  change  its  position  in  the  same 
individual  at  diff'erent  stages  of  development,  but  in  shells  of  the  same  age 
it  is  approximately  constant,  and  is  available  for  diagnostic  purposes  in  a 
number  of  genera. 

The  siphuncle  differs  in  its  form  and  characteristics  among  Paleozoic 
genera,  being  tubulär  in  some  (Fig.  1110),  or  inflated  in  the  interseptal  Spaces 
in  others,  in  such  manner  as  to  resemble  a  string  of  beads,  or  swollen  discs 
which  are  separated  by  narrow  constrictions  (Fig.  1126).  When  of  consider- 
able  width,  its  cavity  is  partly  filled  up  with  thin  calcareous  lamellae  (Fig. 
1137),  partly  with  the  calcareous  cones  immediately  to  be  described  (Fig. 
1105),  or  it  is  notably  reduced  by  excretions  around  the  interior  of  the 
funnels  forming  peculiar  annular  swellings  known  as  rings,  and  which  are 
generally  composed  of  calcareous  matter.  The  centre  of  the  siphuncle  in 
these  forms  is  usually  kept  open  more  or  less  perfectly  by  an  axial  tube 
termed  by  Zittel  the  prosiphon  (endosiphunde  of  Hyatt),  which  will  be  con- 
sidered  more  fully  in  the  descriptions  of  Endoceras  and  Adinoceras.  In 
Diphragmoceras  the  siphuncle  is  septate  like  the  shell.  The  upper  parts  of 
these  large  siphuncles  were  more  or  less  unobstructed  near  the  living  Chamber, 
and  this  part  (the  endoconal  or  siphuncular  diamher  of  Hyatt)  was  doubtless 
occupied  by  an  extension  of  the  mantle  cavity,  probably  containing  portions 
of  the  viscera. 

The  funnel  of  the  siphuncle  as  described  above  is  simple  in  structure,  and 
is  plainly  directed  towards  the  apex  in  all  Nautiloids,  with  the  exception  of 
Nothoceras  and  its  allies,  the  funnels  (?)  of  which  are  turned  in  the  opposite 
direction.  The  funnels,  as  a  rule,  are  short  and  incomplete,  although  in 
the  early  stages  of  development  of  many  shells,  and  in  the  adult  stage  of 
primitive  forms  they  may  be  complete,  extending  from  one  septum  to  the  next 
following  (Fig.  1105),  or  even  to  the  second  preceding  this  (Fig.  1104,  C). 
When  the  funnels  are  complete  they  are  always  contracted  apically,  and 
inserted  one  within  the  other.  The  siphuncle  in  most  Nautiloids,  as  in  the 
existing  Nautilus  (Fig.  1123),  is  apt  to  be  more  or  less  dilated  in  the  younger 
stages,  especially  in  the  second  and  first  air-chambers,  and  it  is  closed  at  the 
end  within  the  first  air-chamber  by  what  is  termed  the  caecum.  The  external 
shell  is  perforated  by  an  elongated  scar  or  cicatrix  (Fig.  1122),  closed  by  a 
plate,  against  some  part  of  which  the  bottom  of  the  caecum  iropinges  in  the 
interior.  The  presence  of  the  cicatrix,  as  already  stated,  leads  to  the  inference 
that  a  deciduous  embryonal  shell  or  protoconch  must  have  been  present.  The 
shell  on  the  apex  is  so  much  thinner  than  at  later  stages,  and  is  so  easily 
abraded  or  destroyed,  and  the  cicatrix  itself  in  consequence  so  slightly  marked 
even  in  perfect  shells,  that  good  examples  are  rarely  found,  and  when  met 
with  require  careful  preparation  and  close  Observation. 


CLASS  V  CEPHALOPODA  593 

In  some  Paleozoic  Nautiloids  with  large  siphuncles  (Endoceras,  Aäinoceras), 
the  apical  end  of  the  siphuncle  is  solid  and  dilated  to  form  the  nepionic  bulb 
(Hyatt),  and  this  sometimes  practically  fiUs  the  camerae,  and  besides  being 
very  large  in  a  number  of  succeeding  Chambers.  The  endosiphuncle  expands 
near  the  apex  in  these  genera,  and  forms  a  good-sized  conical  Perforation  er 
cicatrix,  which  is  obviously  open  at  its  termination  (Adinoceras,  Nanno). 

Closely  coiled  shells  have  the  apical  part  bent  so  as  to  enclose  a  vacant 
Space  (the  umhilical  Perforation)  in  the  centre  of  the  whorls  (Fig.  1119). 
This  is  present  in  all  the  Nautiloidea  having  this  mode  of  growth,  although  in 
some  genera  it  is  very  minute.  The  Nautiloid  shell  is  invariably  cone-shaped, 
but  this  may  be  straight  or  curved,  or  coiled  in  open  or  closed  spirals,  but  in 
rare  instances  it  is  even  screw-like,  or  similar  to  a  Gastropod  shell.  Along 
with  perfectly  smooth  shells,  or  those  marked  only  with  fine  growth-lines, 
which  in  some  rare  cases  may  retain  traces  of  their  original  coloration,  there 
are  others  with  external  transverse  ridges,  keels,  rows  of  tubercles  or  laminae ; 
but  this  ornamentation  is  of  a  simple  kind,  and  never  attains  the  degree  of 
complexity  observed  among  the  more  highly  ornamented  forms  of  Ammonoids. 

Classification. — Great  importance  has  always  been  attributed  to  the  external 
configuration  and  curvature  of  the  shell  in  distinguishing  genera,  and  the 
principal  groups  usually  named  Orthoceras,  Cyrtoceras,  Gyroceras,  Nautilus,  etc., 
have  been  founded  upon  such  characters.  Barrande  emphasised  in  addition 
the  shape  of  the  aperture,  direction  of  the  funnels,  and  structure  of  the 
siphuncle,  but  considered  these  subordinate  in  most  cases  to  the  general 
form,  and  the  majority  of  writers  have  followed  his  example.  Hyatt, 
however,  regarded  the  general  form  and  involution  of  the  shell  as  relatively 
minor  characters,  and  depended  upon  coincidence  of  structure,  outlines  of  the 
aperture,  and  especially  resemblances  in  developmental  stages,  as  surer  guides 
to  the  affinities  of  the  species  and  characteristics  of  the  genera. 

Terminology. — For  sake  of  convenience,  it  is  preferable  always  to  speak  of 
the  embryonal  shell  as  the  protoconch,  and  the  later  or  epembryonic  stages  of 
the  shell  as  the  conch,  the  term  "  shell "  being  really  applicable  to  the  entire 
external  skeleton  inclusive  of  the  protoconch.  The  history  of  the  individual 
and  its  shell  can  be  divided  into  the  following  stages  and  substages  :  The 
emhryo  or  protoconch ;  the  nepionic  stage  or  infancy,  represented  by  the  apical 
part  of  the  conch ;  neanic  stage  or  adolescent  part  of  the  more  mature  cone ; 
ephebic  or  adult  stage  of  the  same ;  and  gerontic  or  senile  stage  with  which  it 
terminates  in  a  complete  example. 

All  of  these  stages  differ  materially  from  each  other  as  a  rule,  and  it  is 
often  convenient  to  divide  them  into  substages,  connoted  by  the  prefixes  ana-, 
meta-,  snid  para-.  Thus  the  nepionic  can  be  separated  into  ananepionic,  meta- 
nepionic  and  paranepionic,  and  it  is  often  essential  to  treat  the  neanic  and 
gerontic  stages  in  the  same  manner.  ^ 

The  many  different  forms  of  Nautiloid  shells  may  be  grouped  into  a  few 
leading  types,  as  foUows  :  An  orthocone  is  the  young  of  the  straight  as  well  as 
of  many  of  the  coiled  forms.  In  this,  although  straight,  the  bands  of  growth 
are  broader  on  the  venter  than  on  the  dorsum,  and  there  is  no  hyponomic 
sinus.  A  cyrtocone  is  the  similar  stage  which  replaces  or,  as  is  oftener  the 
case,  succeeds  this  and  is  curved.     Both  of  these  may  have  crests  in  the  bands 

1  For  a  more  extended  discussion  of  terminology  that  can  be  advantageously  used  in  descriptions 
of  sliells  of  this  class  See  Hyatt,  A.,  Phylogeny  of  au  Acquired  Characteristic,  1894,  p.  422  et  seq. 
VOL.  I  ^  ^ 


594  MOLLUSCA  phylum  vi 

of  growth,  on  both  the  dorsum  and  venter,  thus  indicating  that  the  young 
animal  did  not  possess  a  large  hyponome.  An  orthoceracone  is  the  older  stage 
of  a  straight  form,  and  is  nearly  or  quite  straight  on  both  venter  and  dorsum ; 
the  bands  of  growth  are  approximately  equal,  but  there  is  usually  a  hyponomic 
sinus.  Cyrtoceracones  are  shells  curved  like  Cyrtoceras  on  both  venter  and  dorsum. 
Gyroceracones  are  curved  in  a  loose  spiral  like  Gyroceras,  the  volutions  being 
sometimes  in  contact,  but  there  is  no  impressed  zone,  i.e.  the  venter  is  not 
involved  by  the  overgrowth  of  the  dorsum  belonging  to  the  next  outer  whorL 

The  impressed  zone  in  its  primitive  form  is  the  longitudinal  impression 
formed  in  the  dorsum  by  the  contact  of  the  whorls.  This  is  divisible  into 
two  kinds — the  contact  furrow,  arising  and  lasting  only  when  the  whorls  are 
in  contact ;  and  the  dorsal  furrow,  arising  through  inheritance  in  the  young 
before  the  whorls  come  in  contact.  There  is  also  a  third  modification,  which 
for  the  present  may  be  called  the  persistent  dorsal  furrow.  This  occurs  in  the 
free  senile  whorls  of  some  shells,  and  is  a  remnant  of  the  impressed  zone. 
Finally,  there  is  a  furrow  arising  only  from  contact  in  the  old  age  of  some 
distorted  Ammonoids,  and  hence  may  be  called  the  gerontic  contact  furrow. 
Cyrtoceracones  and  gyroceracones  do  not  usually  have  impressed  zones,  but 
an  exception  is  furnished  by  Cyrtoceras  depressum. 

Nautilicones  are  closely  coiled  shells  having  an  impressed  zone.  This  may 
be  only  a  very  slight  contact  furrow,  or  a  hereditary  dorsal  furrow  deepening 
by  growth  and  Involution,  as  in  Nautilus.  Torticones  are  asymmetrical  spirals 
like  those  of  a  Gastropod,  either  loosely  or  closely  coiled.  These  may  or 
may  not  have  impressed  zones.  Among  Nautiloids  they  may  be  distinguished 
as  trochoceracones,  etc.,  according  to  their  form,  and  among  Ammonoids  as 
turriliticones,  etc.,  when  more  precise  descriptive  terms  are  required.  A  special 
nomenclature  is  employed  in  describing  the  position  of  the  siphuncle,  which 
is  of  convenience  in  technical  treatises,  but  may  be  omitted  here.  The  septal 
Chambers  have  been  termed  camerae  in  the  sequel,  because  this  avoids  any 
assertion  with  regard  to  their  contents,  such  as  is  implied  by  "  air-chambers  " 
and  the  like.  The  less  appropriate  term  "loculus  "  has  been  used  with  the  same 
meaning  by  Holm. 

Order  1.     NAUTILOIDEA    ZitteL 

The  conchs  are  camerated  orthocones  and  cyrtocones  in  the  young  of  primitive 
forms,  hecoming  cyrtoceracones  like  the  adults  of  these  same  ancestral  shells  in  the  young  of 
more  specialised  and  coiled  shells.  Äpertures  have,  as  a  rule,  ventral  or  hyponomic 
sinuses,  and  crests  on  the  dorsum.  Septa  are  concave  along  the  mesal  plane  toioards  the 
apex.  Sutures  straight  or  undulated,  rarely  with  sub-angular  lobes  and  saddles,  and  these 
are  prohahly  never  acutely  angular,  as  in  the  Ämmonoidea.  Each  segment  of  the  siph- 
uncle is  composed  of  a  funnel  and  sheath  as  among  primitive  Ammonoids,  hut  the  funnel 
persists  throughout  life  in  the  ontogeny  of  all  forms  (except  perha]}S  Nothoceras).  Gollars 
around  the  oral  openings  of  the  funnel  are  present  in  the  later  stages  of  Ascoceras  {and 
Nothoceras  ?).  Apex  cup-  or  saucer-shaped,  and  marked  hy  a  circular  or  elongated  cavity 
or  cicatrix,  tühich  is  more  or  less  compressed  elliptical,  never  transversely  elliptical  or 
and  is  sometimes  hidden  hy  the  protoconch  or  its  shrunken  remnants. 


The  Order  may  be  subdivided  according  to  the  general  external  features  of 
the  Shell  and  structure  of  the  siphuncle  into  five  sub-orders,  as  follows,  named  with 
reference  to  peculiarities  of  the  funnels  : — Holochoanites,  Mixochoanites,  Schistochoanites, 


CLASS  V 


CEPHALOPODA 


595 


Orthochoanites  and  Cyrtochoanites.    The  characters  of  these  different  groups  are  defined 
under  tlieir  proper  headings. 


Suborder  A.     HOLOCHOANITES  Hyatt. 

Funnels  of  siphuncular  segments  reaching  from  the  septum  of  origination  to  the  plane 
of  the  next  septum  apicad  or  heyond  this,  or  in  some  geyiera  even  to  the  plane  of  the  second 
septum. 

I.  DiPHRAGMiDA  Hyatt. 

This  groiip  contains  biit  one  family,  Diphragmidae,  having  the  same  characters  as 
the  following  uniqiie  genus  : — 

Diphragmoceras  Hyatt.  Orthoceracones  and  cyrtoceracones  having  simple  septa 
and  sutures  as  in  Endoceratida,  but  siphnncle  divided  by  tabnlae  alternating  with  the 
septa  of  the  camerated  shell.  Chambers  of  siphuncle  empty,  as  are  also  the  camerae. 
Quebec  group. 

II.  Endoceratida  Hyatt, 

Orthoceracones,  cyrtoceracones,  gyroceracones  and  nautilicones  having  siphuncles  of 
variable  diameter,  but  as  a  rule  large  in  proportion  to  the  width  of  the  shell.  They  may  he 
empty  or  filled  ivith  internal  organic  deposits,  but  are  invariably  tubulär,  and  the  funnels 
completely  shut  off  the  interior  from  the  interiors  of  the  camerae.  The  latter  are  without 
organic  deposits. 

Family  1.     Endoceratidae  Hyatt. 

Smooth  or  annulated  orthoceracones.  Siphuncle  alivays  more  or  less  filled  with 
organic  deposits. 

A  B  C 


Fio.  1104. 
A,  Vaghiocems  duplex  (Wahlenberg).  Ordovician ;  Kinneknlle, 
Sweden.  Mach  reduced.  B,  V.  commune  (Wahlb.),  Ordovician  ; 
Oranienbaum,  Russia.  The  anterior  endocone  of  the  siphuncle is 
filled  up  with  niatrix  so  as  to  form  a  dart  ("  Spiess  ").  1/2-  ^',  !>>«- 
gramniatic  longitiulinal  section  of  the  last,  showing  siphonal 
funnels.  D,  Detached  caraera  of  Vcußnoceras  with  long  siphonal 
funnel.    (Figs.  C  and  D  after  Dewitz.) 


Fig.  1105. 

Endoceras  proteiforme  Hall.  Ordovi- 
cian ;  New  York.  Longitudinal  section 
showing  funnels  and  endocones. 


Vaginoceras  Hyatt  (Fig.    1104).     Ordovician.     Cameroceras  Conrad  {Sannionites 
Fischer  von  Waldheim  ;  Suecoceras  Holm).     Ordovician  and  Silurian. 

Endoceras   Hall   {Golpoceras  Hall;    Diploceras  Conrad)   (Fig.   1105).     Smooth  or 


596  MOLLUSCA  phylum  vi 

annulated  orthoceracones.  Funnels  reach  from  septum  of  origination  to  tlie  next 
apicad  of  this,  but  no  farther.  Septa  pass  entirely  arountl  the  sipliuncle.  Organic 
deposits  in  tlie  form  of  endocones,  and  taper  off  at  tha  centre  into  a  spire  that  is 
ßometimes  tubulär  and  hollow,  or  again  flattened  and  elliptical.  This  is  tbe  endo- 
siphuncle.     Ordovician  and  Silurian. 

Narthecoceras  Hyatt.  Long,  cylindrical,  staff-like  ortlioceracones.  Siphuncle 
large  and  filled  witli  organic  deposits  having  a  radiating  fibrous  structure  like  the 
guard  of  a  Belemnite.  Endocones  and  an  endosiphuncle  developed.  Septa  continuous 
around  the  siphuncle.     Ordovician. 

Nanno  Clarke.  Similar  to  the  preceding,  but  endosiphuncle  present  only  at  the 
apieal  end.  Siphuncle  close  to  the  shell,  so  that  sutures  appear  to  bend  apically  into 
a  lobe  passing  around  the  siphuncle.     Trenton  Limestone. 

Family  2.     Piloceratidae  Hyatt. 

Shorter  and  stouter  orthoceracones  and  cyrtoceracones  ivith  relatively  larger  siphuncles 
than  in  Endoceratidae,  and  more  variable  in  their  internal  deposits.  Septa  are  more 
concave  and  sutures  more  sinuous.      Gamerae  empty  and  funnels  similar. 

Piloceras  Salter.  Breviconic  cyrtoceracones  with  very  large  siphuncle  and  well- 
defined  endocones.     Ordovician. 

Family  3.     Oyrtendoceratidae  Hyatt. 

Gyroceracones  and  nautilicones  having  large  siphuncles  filled  with  organic  deposits  or 
empty,  hut  with  endocones  ohscure  or  ahsent,  and  no  endosiphuncles. 

Gyrtendoceras  Remele.  Gyroceracones  with  siphuncle  near  the  dorsum  and  filled 
with  calcareous  deposits.     Ordovician. 


Suborder  B.     MIXOCHOANITES  Hyatt. 

Orthoceracones  and  cyrtoceracones  having  expanded  living  Chambers  with  contracted 
apertures  in  the  gerontic  stage  of  specialised  genera.  The  oldest  septa  are  beut  sharply 
orad,  forming  a  series  of  dorsal  saddles,  and  the  siphuncle  hecomes  highly  modified. 
Primitive  genera  have  the  septa  deeply  concave  or  approximately  sub-conical,  the  siphuncle 
small  and  empty,  and  the  septa  sometimes  more  or  less  imperfect  on  the  ventral  side  in  the 
gerontic  stage.  Specialised  forms  have  siphuncles  with  short,  straight  funnels  in  the 
young,  and  in  the  ephebic  stage  collars  are  built  around  the  oral  openings,  thus  becoming 
parallel  to  some forms  of  Goniatitidae  that  have  similar  composite  funnels. 

Family  L     Ascoceratidae  Barrande. 

Cyrtoceracones,  smooth  or  annulated.  Siphuncle  with  long  funnels  only  in  the  young 
and  later  stages  of  primitive  genera,  but  collars  are  added  in  later  stages  of  specialised 
forms,  and  segments  become  nummuloidal  in  the  gerontic  stage.  Septa  often  more  or  less 
imperfect  around  the  siphuncle  and  on  the  ventral  side. 

Ghoanoceras  Lindstr.  Sections  dej^ressed  elliptical.  Gerontic  stages  have  no 
saddles,  and  living  Chamber  uncontracted.     Ordovician  and  Silurian. 

Aphragmites  Barr.  Only  gerontic  living  Chambers  known ;  these  are  similar  to 
those  of  Ascoceras,  but  have  no  internal  sigmqidal  dorsal  saddles.      Silurian. 

Ascoceras  Barr.  (Figs.  11 06,  1 107).  Gerontic  living  Chambers  internally  contracted 
by   the  formation    of   large  sigmoidal   saddles,   and  septa   more  or  less  incomplete 


CLASS  V 


CEPHALOPODA 


597 


ventrally.     Siphuiicle  with  fuimels  only  in  the  young,  the  collars  in  ephebic  stages 
becoming  nummuloidal  and  often  inconijjlete  in  old  age.     Aperture  open.     Silurian. 
Glossoceras   Barr.      Known   only  by  gerontic   living   Chambers, 
whicli  are  like  those  of  Ascoceras,  except  that  the  aperture  has  dorsal 
and  lateral  crests.     Silurian. 

Volborthella  Schmidt.  *  Minute  orthoceracones  with  conical 
septa,  small  siphuncle,  perfectly  piain  upon  the  surface  of  the  septa. 
Living  Chamber  flaring  and  uncontracted.  Lower  Cambrian ; 
Finland,  Esthonia.     St.  John  Group  ;  Nova  Scotia. 

Family  2.     Mesoceratidae  Hyatt. 

Depressed  elliptical  cyrtoceracones,  known  only  hy  their  gerontic 
living  chamherSy  and  aßnities  therefore  uncertain.  They  are  globular 
at  this  stage,  and  have  highly  contracted^  transversely  elongated,  and 
approximately  dumh-hell  shaped  apertures. 


Wv 


Fio.  1106. 

Äscoceras  mamchrium 
Lindström.  Silurian  ; 
Gotland.  1/2.  (Re- 
stored  after  Lindström.) 


Fig.  1107. 

Äscoceras  bohcmicuvi  Barr.  iSilurian  (Etage  E) ;  Kozorz,  Bohemia.  A, 
Specimeu  with  shell  partially  preserved.  B,  Mould  of  living  Chamber  detached 
from  preceding  portion.  C,  Longitudinal  section.  7t',  Living  Chamber;  c  1-4, 
Camerae  ;  l  1-4,  Saddles  contracting  the  living  Chamber,    i/j  (after  Barrande). 


Mesoceras  Barr.  Aperture  with  very  sliallow  hyponomic  sinus.  No  internal 
gerontic  sigmoidal  septa.     Silurian. 

Billingsites  Hyatt.  Aperture  without  hyponomic  sinus.  Gerontic  living  Chamber 
partly  fiUed  by  dorsal  sigmoidal  saddles  as  in  Äscoceras,  but  septa  complete  on  the 
ventral  side.     Silurian. 


Suborder  C.     SCHISTOCHOANITES  Hyatt. 


Funnels  usually  more  or  less  imperfecta  present  on  the  internal  side,  and  ahscnt  or 
split  on  the  outer  side. 

The  typical  form  of  the  suborder  is  Conoceras  Bronn. 

Gyrtocerina  Billiugs.  Breviconic  cyrtoceracones.  Siphuncle  large,  on  the  concave 
side  and  empty,  but  having  internal  ridges  alternating  with  septa  of  the  camerae. 
These  ridges  appear  to  indicate  affinity  with  Conoceras.     Ordovician. 

Conoceras   Bronn  {Bathmoceras    Barr.)   (Fig.    1108).       Breviconic    orthoceracones, 


598 


MOLLUSCA 


PHYLUM  VI 


known  only  in  their  later  stages  of  development.  Sipliuncle  of  moderate  size,  sub- 
ventran.  Funnels  reaching  lialf-way  across  each  camera,  steeply  inclined  orad,  and 
split  on  tlie  outer  side.  Closure  of  the  walls  effected  by  a 
plate  extending  from  the  apical  opening  of  each  funnel  through 
the  funnel  itself  orad  to  the  apical  opening  of  the  next 
beyond,  and  projecting  into  the  interior  as  a  flattened  fold, 
which  is  incomplete  or  open  along  the  central  axis.  These 
internal  coUars  or  flat  semiconical  rings  have  been  described 
as  complete  cones  (Dwight).     Ordovician. 

Suborder  D.     ORTHOCHOANITES  Hyatt. 

'  Gerontic  stages  have  uncontracted  volutions  and  open  aper- 

tures,  except  in  a  few  uncoiled  phylogerontic  genera.      Siphun- 
Fio,  1108.  cular  Segments  may  he  slightly  nummuloidal,  fusiform  or  tubulär, 

Conoceras  pracpost^rum  hut  are  never  marJcedly  nummuloidal,  nor  are  the  funnels  hent 
D)rVosä^^Bohemia^fafter  ^harply  outwards  as  in  Gyrtochoanites.  Deposits  formed  only  in 
Barrande).  the  siphuncles  of  Orthoceratidae   and  Kionoceras,  and  in   them 

they  are  irregulär  and  no  endosiphuncles  occur ;  other  genera 
have  empty  siphuncles.  Funnels,  as  a  rule,  hoth  longer  and  straighter  than  in  Gyrto- 
choanites, and  in  Aturia  almost  equal  to  those  of  Holochoanites. 

This  group  includes  the  greater  number  of  Nautiloid  forms,  passing  from  the 
smoothest  to  the  most  highly  ornamented  of  Paleozoic  shells,  continuing  in  the  Trias 
as  nautilicones  of  complex  ornamentation,  and  terminating  with  smooth  shells  that 
ränge  from  the  Jura  to  the  present  time.  The  sutures  become  more  sinuous  and  com- 
plex in  one  of  the  subdivisions  than  in  all  other  Nautiloids.  The  increase  in  number 
of  lobes  and  saddles  begins  in  the  Trias  with  Glymenonautilus,  and  ends  with  Aturia 
in  the  Tertiary. 


I.  Orthoceratida  Hyatt. 

Orthoceracones  and  cyrtoceracones  with  smooth  or  ornamented  shells,  and  not  as  a 
rule  contracted  in  gerontic  stage ;  apertures  open  throughout  life.  Although  often  short, 
none  are  hrevicones,  strictly  speahing.  Section  circular  or  elliptical,  very  rarely  oval. 
Siphuncle  with  slightly  nummuloidal,  fusiform  or  tubulär  segments,  and  generally  near 
the  centre. 


Family  1.     Orthoceratidae  M'Coy. 


Section  circular  or  compressed,  living  chamher  uncontracted  or  only  slightly  so, 
and  aperture  always  open.  Surface  smooth  or  with  only  transverse  bands,  rarely 
longitudinal  Striae,  never  longitudinal  ridges.  Siphuncle  small  (except  in  Baltoceras), 
Segments  fusiform  or  cylindrical,  never  nummuloidal.  Deposits  when  present  irregulär, 
and  gathered  about  the  funnels  as  in  the  Gyrtochoanites  ;  no  definite  endosiphuncles  ever 
formed. 

Baltoceras  Holm.  Siphuncle  large,  but  with  short,  straight  funnels,  and  sheatlis 
as  in  Orthoceras.     Ordovician. 

Orthoceras  Breyn  (Figs.  1109,  1110).  Long  tapering  orthoceracones  and  cyrto- 
ceracones, smooth,  or  with  only  transverse  Striae  and  growth  bands.  Siphuncle 
generally  larger  than  in  Geisonoceras,  centren  or  slightly  dorsad  of  centre.  Deposits 
when  present  gathered  about  the  funnels  as  in  the  Annulosiphonata.    Silurian  to  Trias. 

Geisonoceras  Hyatt  (Fig.  1111).  Similar  to  the  last,  but  sides  spreading  more 
rapidly,  and  siphuncle  empty,  centren  or  slightly  ventrad  of  centre.  Ordovician  to 
Carboniferous. 


CLAss  V  CEPHALOPOJ)A  599 

Protobactrites    Hyatt.       Long   i)encil-shaped    orthoceracones    and    cyrtoceracones, 


Fio.  1100. 

Orthocerasinter medium  Marklin.  Siluriaii ; 
Gottland.  Longitudinal  section  showing 
siplmncle,  septa  and  pseudosepta  ;  camerae 
lilled  up  witli  calcite. 


Fig.  1110. 

Orihoceras  michelini 
Barr.  Silurian ;  Kozorz, 
Boheniia.  Longitudinal 
section  showing  sliort 
sii)honal  funnels. 


circiilar,  or  compressed  elliptical  in  section,  ornamented  with 
transverse  and  sometiines  longitudinal  Striae.  Siphuncle 
tubulär,  centren  or  near  the  centre.  Truncation  occurs  in  soiiie 
species,  and  others  are  more  or  less  transitional  to  Bactrites 
among  the  Ammonoids.  Type  P.  {Oriho- 
ceras) styloideum  (Barr.).  Silurian  to  Car- 
boniferous. 

Family  2.     Oycloceratidae  Hyatt. 


Fio,  1111. 

Geisonoccras  timidum 
(Barr.).  Silurian ;  Loch- 
kow,  Bohemia. 


Orthoceracones  and  cyrtoceracones  having  annuli  with  transverse 
Striae  or  bands  of  growth  at  all  stages  ;  longitudinal  ridges^  when 
jjresent,  more  or  less  discontinuous.  The  earliest  forms  often  have 
large  siphuncles,  and  are  apparently  more  directly  connected  with 
primitive  Endoceratida  than  with  the  Orthoceratidae. 

Protocycloceras  Hyatt.  Annulated  orthoceracones  and  cyrto- 
ceracones without  longitudinal  ridges.  Siphuncle  large.  Type 
P.  {Orihoceras)  lamarcki  (Bill.).      Ordovician. 

Cycloceras  M'Coy  {Dictyoceras,  Heloceras  Eichw.).  Annulated 
orthoceracones  and  cyrtoceracones  with  discontinuous  longitudinal 
ridges.  Siphuncle  generally  tubulär  or  with  fusiform  segments ; 
deposits  when  present  irregulär  as  in  Orihoceras.  Annuli  often 
become  obsolete  in  paragerontic  stages.     Ordovician  to  Perniian. 

Daiüsonoceras  Hyatt  (Fig.  1112).  Siniilar  to  Cycloceras,  but 
having  prominent  frilled  bands  of  growth  between  and  on  the 
annulations,  the  frills  sometimes  forming  more  or  less  discon- 
tinuous longitudinal  ridges.     Silurian  and  Devonian. 

Gtenoceras  Noetling.  Cyrtoceracones  like  Dawsonoceras  dulce 
(Barrande),  but  with  fine  longitudinal  ridges  between  the  annuli, 
and  living  chamber  with  three  internal  folds  or  processes — one 
median  dorsan,  and  a  pair  on  the  venter.  SiiJhuncle  dorsad  of 
centre.     Ordovician. 

Family  3.     Kionoceratidae  Hyatt. 
Orthoceracones  and  cyrtoceracones  with  more  or  less  well-marked  continuous  longi- 


FiG.  1112. 

Dawsonoceras  annula- 
tum  (Sowb.).  Silurian 
(Etage  E) ;  Viscocilka, 
Bohemia.  Terminalpor- 
tion showing  Shell  of 
living  Chamber  and 
sectioned  camerae (after 
Barrande). 


600 


MOLLUSCA 


PHYLUM  VI 


tudinal  ridges,  and  either  with  or  ivithout  annulations.  Spinous  ])rocesses  or  tuhercles 
often  appear  at  the  intersections  of  the  longitudinal  and  transverse  hands  of  growth. 
Siphuncle  with  faintly  iiummuloidal,  fusiform  or  tubulär 
Segments. 

Kionoceras  Hyatt.  Longitudinal  ridges  present  as  a  rule 
only  in  the  earlier  stages,  after  wliich  inconspicuous  annuli 
appear,  but  with  some  few  exceptions  become  obsolete  before 
the  ephebic  stage.     Silurian  to  Carboniferous. 

Spyroceras  Hyatt.  Very  long,  slender,  annulated  shells, 
with  more  or  less  prominent  longitudinal  ridges  in  the  ephebic 
stage.      Ordovician  to  Carboniferous. 

Thoracoceras  Eichw.  {Melia  Eichw.)  (Fig.  1113).  Like  the 
last,  but  with  more  or  less  spinous  longitudinal  ridges.  Silu- 
rian to  Carboniferous. 


IL  Plectoceratida  Hyatt. 

Orthoceracones,  gyroceracones,  and  very  discoidal  nantilicones 

with  comparatively  slight  impressed  zone.      Volutions  of  gerontic 

stage    often    have    a    centrifugal    tendency,    becoming    sometimes 

straight  and  even  bending  slightly  in  the  opposite  or  ventral  direction. 

p  ^.  Shells  annulated  or  costated,  and  often  ivith  longitudinal  Striae  or 

Thoracoceras  corbulatum  -^^^  ridges,  especially  in  the  young,  but  these  generally  disappear 

(Barr.).      Silurian   (Etage    before   the   ephebic   stage.      Siphuncular   Segments  slightly   num- 

E);  Dvoretz.Bohemia (after  i    -j    i    x      -x  ±    i     i 

Barrande).  muloidal,  fusiform  or  tubulär. 


Family  4.     Tarphyceratidae  Hyatt. 

Orthoceracones,  cyrtoceracones,  gyroceracones  and  nautilicones,  compressed  oval  in 
section,  venter  narrower  than  the  dorsum.  Shell  smooth  or  Sometimes  with  primitive  fold- 
like  costae.     Siphuncle  empty,  tubulär  and  ventrad  of  centre. 

Aphetoceras,  Deltoceras,  Barrandeoceras,  Tarphyceras  Hyatt ;  Planctoceras,  Eury- 
stomites  Schröder ;  Falcilituites  Eemele.  Ordovician.  (For  descriptions  see  Hyatt's 
Phylogeny,  1894.)  Eurystomites  and  Tarphyceras  are  whoUy  nautilicones,  the  remain- 
ing  genera  are  either  cyrtoceracones  or  gyroceracones. 


Family  5.     Trocholitidae  Hyatt 

Nautilicones  resembling  those  of  the  preceding  family,  and  not  easily  distinguished 
from  them  in  the  young.  As  a  rule  they  have  excessively  broad  volutions  with  reniform 
section  and  an  impressed  zone  at  a  very  early  age ;  the  siphuncle  is  then  ventrad  of  the 
centre,  but  in  the  ephebic  stage  it  is  tubulär  and  dorsad  of  centre. 

Schroederoceras,  Litoceras,  Trocholitoceras  Hyatt;  Trocholites  Conrad  {Palaeo- 
nautilus,  Palaeoclymenia  Remele).  Ordovician.  Discoceras  Barrande.  Ordovician 
and  Silurian. 


Family  6.     Plectoceratidae  Hyatt. 

Gyroceracones,  nautilicones  and  torticones  having  annular  costae  from  the  neanic 
stage  until  late  in  life,  and  in  some  genera,  more  or  less  prominent  longitudinal  ridges, 
which  usually  disappear  in^  the  ephebic  stage.     Siphuncle  ventrad  of  centre. 


CEPHALOPODA 


601 


Pledoceras  Hyatt.     Ordovician  and  Silurian.     Sphyradoceras  Hyatt  {Peismoceras, 

Systrophoceras     Hyatt)     (Fig.  _ 

1114).  Silurian       and 

Devonian.  The  first  is  gyro- 
ceraconic,  with  some  discoidal 
nautilicones,  and  the  second  is 
almost  exclusively  torticonic 
of  tlie  trochoceran  type. 


Family  7.     Ophidio- 
oeratidae  Hyatt. 

Discoidal  nautilicones^ 
costated  from  the  neanic  stage 
onward.  Volutions  of  the 
young  small  and  numerous. 
Section  during  the  ephebic  stage 
generally  compressed,  venter 
narrower  than  the  dorsum. 
Siphuncle  tubulär,  small. 


Fi«.  1114. 

Sphymdoceras  optaUim  (Barrande).     Silurian 
(Etage  E) ;  Lochkow,  Bohemia  (after  Barrande), 


the  young. 


Ophidioceras    Barr.    (Fig. 
1115).       Nautilicones    with 
straight    lateral    costae    and 
raised  bands  on   the  venter, 
and    longitudinal    ridges    in 
Siphuncle  dorsad  or  ventrad  of  centre  during  ephebic 
stage,  biit  ventrad  during  the  nepionic. 
Gerontic  apertures  with  prominent  dorsal 
and  lateral  crests,  and  very  deep  hypo- 
nomic  sinus.     Silurian. 

Homaloceras  Whiteaves.  Cyrtocera- 
cönes  with  section  similar  to  that  of  Ophi- 
dioceras, venter  narrow  and  channelled, 
bordered  by  crenulated  ridges ;  the  dorsum 
gibbous  and  rounded.  Siphuncle  near 
the  venter.     Devonian. 


Family  8.     Lituitidae  Noetling. 


Ophidioceras  simpUx  Barr, 
Silurian  (Etage  B);  Lochkow, 
Bohemia.     i/i  (after  Barrande). 


Excepting  the  supposed  ancestral, 
primitive  genus,  Gyclolituites,  this  is  a 
series  of  phylogerontic  uncoiled  forms  with 
an  extreme  modification  in  the  almost 
completely  uncoiled  Rhynchorthoceras. 
Apertures  quite  distinct  from  those  of  the  preceding  family  ;  hyponomic 
sinus  shallower,  there  are  narroio  ventro-lateral  crests,  and  small  lateral 
sinuses  and  crests,  some  forms  having  altogether  as  many  as  five  sinuses 
and  five  crests.     Biphuncle  tubulär  and  usually  largc. 


Fio.  1116. 

Lituites   lituus 
Montf.     Ordovician 
drift ;  East  Prussia. 
1/2  (after  Noetling). 
Gyclolituites  Remele  ;  Lituites  Breyn  {Fig.  1116);  Angelinoceras, 

Holmiceras  Hyatt.      Ordovician.      Ancistroceras  Boll,  and  Rhynchorthoceras  Remele. 

Ordovician  and  Silurian.     (For  re-descriptions  see  Hyatt's  Phylogeny,  1894.) 


602 


MOLLUSCA 


PHYLÜM  VI 


II I.  Pleuronautilida  Hyatt. 

Gomparatively  smooth  naufAlicones,  the  primitive  genera  discoidal  hut  leading  up  to 
some  highly  involute  shells  in  the  Trias.  The  later  Mesozoic  and  Tertiary  shells  nearly 
all  deeply  involute.  Some  of  the  Triassic  Glydonautilidae  have  more  sinuous  sutures 
and  a  greater  number  of  lobes  and  saddles  than  any  other  Nautiloids,  and  this 
complexity  persists,  although  to  a  lesser  degree,  among  the  Jurassic,  Gretaceous  and 
Tertiary  forms.  Siphuncle  tubulär  and  small,  with  mostly  short  funnels  except  in 
Äturia,  where  they  are  very  long. 

Family  9.     Grypoceratidae  Hyatt. 

Primitive  forms  have  discoidal  volutions  ivith  very  simple  sutures^  but  are  succeeded 
hy  involute  shells  having  more  complete  sutures.  The  latter  have  promAnent  ventral 
saddles  sometimes  divided  by  a  lobe,  and,  large  lateral  and  dorsal  lobes.  All  genera 
save  one  known  to  have  annular  lobes.  Shells  less  highly  ornamented  than  in  preceding 
family,  and  sutures  simpler  than  in  the  next  following. 

Syringoceras  Hyatt.  Discoidal  with  primitive,  approximately  tubulär,  or  sliglitly 
compressed  volutions.  Surface  marked  by  lougitudinal  ridges,  sometimes  intersecting 
the  transverse  lines  so  as  to  produce  a  cancellated  surface.  Sutures  with  faint  ventral 
saddles,  slight  lateral  and  dorsal,  and  minute  annular  lobes.  Siphuncle  very  small 
and  near  the  venter.      Trias. 

Grypoceras  Hyatt.  Volutions  more  or  less  deeply  involved,  but  umbilicus  open, 
the  venter  narrow  and  often  channelled.  Sutures  with  narrow,  sometimes  deep  ventral 
lobe,  broad,  sweeping  lateral  lobes,  and  deep  dorsal  with  annular  lobes.  Siphuncle 
dorsad  of  centre.     Trias. 


Family  10.     Glydonautilidae  Hyatt. 

Shells  have  folds  in  some  species,  and  all  are  deeply  involute  except  the  primitive  genus 

Glymenonautilus.  Lateral  lobes  of  sutures  more 
or  less  deep  and  often  sub-angular,  suggestive  of 
the  Glymenidae  among  Ammonoids.  Some  highly 
specialised  and  involute  species  have  the  umbilical 
lobes  exposed  on  the  sides,  and  an  additional 
pair  of  laterals  developed  near  the  venter,  thus 
making  three  pairs  of  lobes  on  each  side.  The 
compressed  volutions,  narrow  venter,  and  aspect 
of  the  young  and  primitive  forms  seem  to  in- 
dicate  dose  affinity  with  the  Grypoceratidae,  but 
only  a  few  species  of  late  Mesozoic  time  are 
known  to  have  annular  lobes. 

Glymenonautilus  Hyatt.  Smooth,  discoidal 
Shells  with  more  or  less  compressed  volutions, 
and  narrow  convex  venter.  Sutures  with  pro- 
minent ventral  saddles,  one  pair  of  deep  lateral 
lobes,  and  large  marginal  saddles.  Siphuncle 
supposed  to  be  near  the  venter.  Type  G. 
{Nautilus)  ehrlichi  (Mojs.).  Trias. 
Fin.  1117.  Glydonautilus      Mojs.        Deeply     involved 

Herc<^lossaf^n«n^a(0^^)^j„^rj.ra ;     „autilicones  with  compressed  volutions,  narrow 

concave  venter,  and  umbilicus  small  or  closed. 
Sutures  with  prominent  ventral  saddles  undivided  by  ventral  lobes  in  adults  hells.  Trias 


CLASS  V  CEPHALOPODA  603 

Hercofjlossa  Conrad  {Enclimatoceras  Hyatt)  (Fig.    111'7).      Deeply  involute,  with 
sutures  like  those  in  Glyphioceratidae,  Ijut  the  ventral  saddle  not  divided  by  even  the 
shallow  lobe  nsually  found  in  tliat  faniily.    Annular  lobes  present 
only  in  some  species.    Siplumcle  small,  centren  or  dorsad  of  centre. 
Trias  to  Tertiary. 

Pseudonautüus  Meek.  Similar  to  Hercoglossa,  but  with  lobes 
on  the  venter,  and  two  saddles  on  either  side.  Large  annular 
lobes  present.     Jura. 

Äturia,  Bronn  (Fig.  1118).  Similar  to  Hercoglossa,  but  with 
large  siphuncle  close  to  the  dorsuni  from  an  early  stage  onward, 
and  funnels  very  long  and  larger  than  in  any  genus  of  Mesozoic 
or  Tertiary  Nautiloids.     Eocene  and  Miocene. 


IV.  Ryticeratida  Hyatt. 
Cyrtoceracones,    gyroceracones    and   naütüicones    having   shells  ^^^'"  ■'^^.^" 

covered  with  more  or  less  projecting  hands  of  groivth  which  often  Mioce^ef Bordeaux'. 

hecome  sinuous  or  develop  into  spout-like  spinöse,  or  nodose  pronii-  ^^^^'^   broken  open   to 

r      .1  '    T     1     1    n     .1  ,    ,     7  /.       ,  Show  siphonal  funnels. 

nences.     In  the  more  speciahsed  shells  these  are  apt  to  he  confined 

to  the  venter.      The  frills  in  the  hands  often  form  coarse  longitudinal  ridges.     Siphuncle 
tubulär  or  slightly  nummuloidal,  and  commonly  ventrad  of  centre. 

Family  11.     Halloceratidae  Hyatt. 

Orthoceracones  and  cyrfoceracones  having  depressed  elliptical  or  suh-trigonal  sections, 
venter  hroader  than  the  dorsum,  Shell  with  closely  set  and  frilled  projecting  hands  of 
growth,  having  large  ring-like  hands  at  intervals  that  sometimes  expand  so  as  to  form 
wide  collars.  The  highly  specialised  nautilicones  may  have  a  row  of  large  nodes  on 
either  side  springing  from  the  hases  of  large  spout-like  spines.  Siphuncle  tubulär ^  small, 
and  near  the  venter. 

Zitteloceras  Hyatt.  Cyrtoceracones  of  depressed  elliptical  section,  the  venter 
narrower  and  more  gibbous  than  the  dorsum.  The  layers  finely  frilled  and  closely 
set  in  the  intervals  between  more  prominent  annular  bands.     Ordovician  to  Devonian. 

Halloceras  Hyatt.  Gyroceracones  of  sub-trigonal  section,  the  venter  broad  and 
dorsum  sub-angular,  with  one  row  of  large  nodes  at  each  of  the  ventro-lateral  angles. 
Devonian. 

Family  12.     Ryticeratidae  Hyatt. 

Cyrtoceracones  and  gyroceracones  resemhling  Halloceratidae,  but  much  larger,  with 
coarser  crenulated  bands,  and  often  with  rows  of  spout-like  spinous  processes  which  some- 
times form  coarse  longitudinal  ridges.  Siphuncle  more  or  less  nummuloidal,  and  larger 
than  in  the  Halloceratidae. 

Ryticeras  Hyatt  {Rutoceras  Hyatt),  Cophinoceras,  Strophiceras  Hyatt.     Devonian. 

V.  Khadinoceratida  Hyatt. 

Cyrtoceracones,  gyroceracones  and  nautilicones  having  smooth  or  spinous  longitudinal 
ridges  in  the  young,  which  hecome  large  and  ßuted  in  some  genera,  hut  disappear  in 
others.  Ridges  more  or  less  sporadically  comhined  with  fold-like  annulations,  thus 
suggesting  direct  descent  from  the  Kionoceratidae. 

Family  13.     Rhadinoceratidae  Hyatt. 

Primitive  discoidal  gyroceracones  and  nautilicones  ivith  stout  volutions,  circular  or 
depressed  elliptical  in  section,  but  hecoming  reniform  in   later  stages  of  nautilicones. 


604 


MOLLUSCA 


PHYLUM  VI 


Shells  with  longitudinal  ridcjes  and  sometimes  annular  folds  in  the  young,  hut  often 
smooth  in  the  ephehic  stage.  Sutures  ivith  ventral,  lateral  ^and  dorsal  lohes,  or  almost 
straight  Siphuncle  nummuloidal  and  often  dorsad  of  centre.  Annular  lohes  knoimi  to 
he  present  in  specialised  forms. 

Rhadinoceras,  Nephriticeras  Hyatt.     Devonian. 

Family  14.     Trigonoceratidae  Hyatt. 

Gyroceracones  and  nautilicones  having  at  some  stage  or  throughout  life  trigonal 
volutions,  a  more  or  less  concave  venter,  and  generally  fluted  shelL  Sutures  with  ventral 
saddles  in  the  young,  hecoming  divided  hy  shallow  lohes  in  later  stages,  and  in  some  genera 
the  dorsal  lohes  of  the  young  hecome  divided  suhsequently  hy  dorsal  saddles.  Gerontic 
living  chamher  occasionally  free  near  the  aperture.  Annular  lohes  ohserved  in  only  one 
species  (Apheleceras  disciforme).  Young  have  longitudinal  ridges  roughened  hy  transverse 
hands  as  in  Thoracoceras.     Siphuncle  small,  ventrad  of  centre. 

Trigonoceras    M'Coy ;    Goelonautilus    Foord    {Trematodiscus    Meek ;    Trematoceras 

Hyatt) ;  Suhclymenia  d'Orb.  ;  Strohoceras, 
Apheleceras,  Diorugoceras,  Ephippioceras 
Hyatt.  Carboniferous.  All  nautilicones 
but  the  first,  which  is  gyroceraconic. 

Family  15.     Triboloceratidae  Hyatt. 

Gyroceracones  and  nautilicones  similar 
to  Trigonoceratidae,  and  with  concave 
venter  at  an  early  stage  or  until  late  in 
life.  The  venter  afterwards  hecomes  more 
or  less  elevated,  and  in  most  species  convex. 
Sutures  also  similar,  hut  annular  lohes 
are  present  in  all  the  nautilicones  save 
Coloceras. 


Fig.  1119. 

Vestinautütis  konincki  (d'Orb. ).  Lower  Carboniferous  ; 
Tournay,  Belgium.  Oral  and  lateral  aspects  of  young 
individual,  with  umbilical  Perforation. 


Triholoceras  Hyatt;  Vestinautilus  Ryckh.  (Fig.  1119);  Planetoceras,  Stearoceras, 
Goloceras  Hyatt.     Carboniferous. 

Family  16.     Rhineceratidae  Hyatt. 

Gyroceracones  and  nautilicones  like  Thoracoceras  in  nepionic  stage,  hut  suhsequently 
hecoming  Uangular  in  section,  and  generally  developing  solid,  more  or  less  tetragonal, 
volutions.  Longitudinal  ridges  and  flutes  also  developed,  hut  are  more  uniform  in  size 
than  in  the  preceding  family,  and  venter  is  always  convex.  Annular  lohes  present  in 
all  nautilicones  so  far  as  Jcnown. 

Ehineceras,  Lispoceras,  Thrincoceras,  Phloioceras,  Discitoceras  {Discites  M'Coy), 
Leuroceras,  Phacoceras  Hyatt.     Carboniferous. 


.  VI.  Hercoceratida  Hyatt. 

^  Primitive  shells  have  projecting  hands  of  groivth  and  processes  similar  to  those  of 
primitive  Ryticeratida,  hut  less  numerous,  heing  present  in  only  one  row,  and  evolving 
more  rapidly  into  nodose  or  symmetrical,  spout-like,  spinous  processes:  More  specialised 
forms  are  tuherculated  as  in  Ryticeratida,  hut  there  are  never  more  than  three  rows  of 
nodes  on  either  side,  and  these  are  regiUarly  distrihuted — one  on  the  umhilical  Shoulder, 
another   on   the   ventro -lateral  angle,  and  the   third  dose  to   the  median  ventral  line. 


CLASS  V 


CEPHALOPODA 


60/ 


Ännular  lohes  ahsent  except  in  a  feto  Triassic  forms.     Siphuncle  generally  more  or  less 
nummuloidal. 

Family  17.     Hercoceratidae  Hyatt. 

Gyrtoceracones,  gyroceracones,  nautilicones  and  torticones  having  depressed  elliptical 
suh-quadrate  or  trapezoidal  sections.     Aperture  has  two  deep  sinuses  with  projecting  edges 


Fig.  1120. 

Hercoceras  mirum  Barr.     Devonian  (Etage  G) ;  Hlubocep,  Bohemla 
(after  ßarraiide). 


Ptenoceras  (Gyr.)  cdatum 
(Barr.).  Silurian  (F)  ; 
Konieprus,  Bohemia.  i/i 
(after  Barrande). 


at  the  ventro-lateral  angles,  and  these  are  usually  persistent,  forming  two  lines  of  more  or 
less  spout-like  processes.  Sutures  with  ventral,  lateral  and  dorsal  lohes.  Siphuncle 
ventrad  of  centre. 

Hercoceras  Barr.  (Fig.  1120),  Trochoceras  Barr.;  Ptyssoceras,  Ptenoceras  (Fig.  1121), 
Anomaloceras  Hyatt.     Devonian. 


Family  18.     Tainoceratidae  Hyatt. 

Discoidal  nautilicones  with  more  or  less  massive  volutions  which  at  some  stage  or 
throughout  life  are  trapezoidal  in  section,  tuherculated,  and  without  well-deßned  lateral 
and  umhilical  zones.  Sutures  have  ventral,  lateral  and  dorsal,  hut  no  annular  lohes. 
Spinous  processes  are  complete,  never  spout-like.     Siphuncle  bmall,  tubulär. 

Temnocheilus  M'Coy  {Endolohus  Meek  and  Wortli ;  Gryptoceras  d'Orb.).  Section 
trapezoidal  throughout  life,  and  one  row  of  persistent  spines  and  nodes  on  either 
side  at  the  ventro-lateral  angles.     Devonian  to  Carboniferous. 

Foordiceras  Hyatt.  Permian.  Metacoceras  and  Coelogasteroceras  Hyatt.  Carboni- 
ferous.    Diadiploceras  Hyatt.     Devonian.  '  Tainoceras  Hyatt.     Carboniferous. 


Family  19.     Oentroceratidae  Hyatt. 

Gyroceracones  and  nautilicones  with  young  similar  to  early  stages  of  Temnocheilus 
htfore  the  impressed  zone  is  formed.  Shell  suhsequently  hecoming  tetragonal  in  section, 
the  venter  is  flattened  or  concave,  and  dorsum  remaining  convex  until  a  late  stage. 
Nautilicones  have  a  persistent  convex  centran  area  in  the  impressed  zone.  No  annular 
known.  '  , 


606  MOLLUSCA  phylum  vi 

Gentroceras  Hyatt.  Devonian  to  Carboniferous.  Tetragonoceras  Whiteaves. 
Devonian. 

Family  20.     Pleuronautilidae  Hyatt. 

Mo.re  or  less  discoidal  nautilicones  with  stout  volutions  and  large  umhilical  perfora- 
tions ;  the  young,  especially  in  primitive  species,  remaining  cyrtoceracones  until  a  late 
stage.  More  specialised  shells  are  costated  and  tuherculated  on  the  sides.  Sutures  have 
annular  lobes  except  in  Pselioceras.  Siphuncle  ventrad  of  centre  in  the  young,  hut 
hecoming  dorsad  in  later  stages. 

Pselioceras  Hyatt.  Permian.  Pleuronautilus  Mojs.  ;  Encoiloceras,  Enoploceras, 
Änoploceras  Hyatt.     Trias. 

VII.    KONINCKIOCERATIDA  Hyatt. 

Nautilicones  with  hiangular  sections  at  an  early  stage  of  growth,  developing  later 
into  modißed  trapezoidal  outlines  as  in  many  of  the  Hercoceratida,  hut  shells  are  smooth, 
and  the  trapezoidal  form  as  a  rule  evolves  during  the  phylogeny  into  quadrangular,  and 
finally  into  involute  coils  with  compressed  sections,  or  may  become  simply  more  or  less 
trigonal  through  elevation  of  the  venter.  Annular  lohes  present  in  most  genera. 
Aperture  constantly  open,  and  in  some  forms  remarJcahle  lateral  projections  are  developed 
during  the  gerontic 


Family  21.     Koninckioceratidae  Hyatt. 

Shells  of  primitive  forms  similar  to  Temnocheilus,  hut  leading  into  those  with 
tetragonal  sections,  and  finally  into  highly  compressed  volutions.  All  are  smooth  and 
have  marked  umhilical  saddles.  Volutions  vnth  hroad  umhilical  zones  which  hecome 
lateral  in  the  more  involute  species.     Siphuncle  ventrad  of  centre. 

KonincMoceras,  Domatoceras  Hyatt.  Carboniferous.  Potoceras  Hyatt.  Devonian  (?). 
Stenopoceras,  Peripetoceras  Hyatt.     Permian. 

Family  22.     Solenocheilidae  Hyatt. 

Compressed  elliptical  in  section  during  early  stages,  hut  full-grown  of  primitive  forms 
and  young  of  specialised  derivatives  have  a  more  or  less  trigonal  section  in  neanic  stage. 
Later  this  stock  evolves  shells  with  volutions  having  depressed  elliptical  or  hroadly  hemi- 
spherical  outlines.  Sutures  generally  have  large  ventral  saddles,  and  saddles  on  the 
umhilical  Shoulders.  Umhilical  zone  very  hroad,  the  increase  hy  growth  of  the  dorsum 
heing  remarkahly  rapid.  Shells  smooth,  hut  the  aperture  in  the  gerontic  stage  may  develop 
peculiar  lateral  projections,  especially  at  the  umhilical  Shoulders,  which  are  usually  very 
prominent.     Siphuncle  suh-ventran. 

Aipoceras,  Oncodoceras  Hyatt ;  Asymptoceras  Ryckholt ;  Solenocheilus  Meek. 
Carboniferous.     Pteronautilus  Meek.     Permian. 

Acanthonautilus  Foord.  Nautilicones  with  sub-hemispherical  volutions,  the  dorsum 
flattened  or  concave.  Aperture  developing  laterally  into  two  projecting  spines  at  the 
umhilical  Shoulders.     Carboniferous. 

VIII.  DiGONiocE RATIDA  Hyatt. 

Primitive  forms  constantly  retain  depressed  volutions  having  a  more  or  less  hiangular 
or  suh-trigonal  section  ;  specialised  shells  repeat  these  stages  in  the  young,  hut  suhsequently 
hecome  more  involute,  and  the  sections  change  to  reniform,  suh-quadrangular  or  suh- 
elliptical.  Shells  smooth  except  in  the  single  genus  Gymatoceras.  Aperture  simple  and 
open  at  all  stages ;  gerontic  living  chamher  only  slightly  contracted. 


CLASS  V 


CEPHALOPODA 


607 


Family  23.     Estonioceratidae  Hyatt. 

Gyroceracones  and  discoidal  nautüicones  having  sUghtly  depressed,  hroad,  rapidly 
increasing  hiangular  sections  in  the  young,  tut  hecoming  depressed  oval  or  depressed 
suh-trigonal  in  later  stages.     Siphuncle  variable  in  position. 

Estonioceras  Noetl.  Ordovician.  Edaphoceras,  Remeleoceras,  Lophoceras  Hyatt ; 
Diodoceras  Hyatt.  Type  D.  (Endolohus)  avonense  (Dawson).  Carbon  iferous.  Digonio- 
ceras  Hyatt.     Jura. 


Family  24.     Nautilidae  Owen. 

Nautilicones  wiih  more  or  less  involved  volutions,  the  siphuncle  slightly  nummuloidal 
and  variable  in  position,  but  never  near  either  the  dorsiim  or  venter  except  in  the  young, 
when  it  is  frequently  either  near  the  dorsum  or  is  centren.  Biangular  stage  much 
abbreviated  or  absent,  the  trigonal  stage  present  in 
most  Shells  for  a  more  or  less  prolonged  period,  but 
developing  invariably  by  spreading  of  the  venter  into 


FifJ.  1122. 

Nautilus  pompilius  Linn. 
Recent.  Portion  ofconch  showing 
linear  cicatrix  at  apical  end  (after 
Hyatt). 


Fio.  1123. 

Apical  Chamber  and  first 
volution  of  N.  pompilius, 
sectioned  longitudinally. 
s,  Siphuncle;  c,  Blind 
origin  of  caecum;  x,  Euipty 
Space  or  uuibilical  Perfora- 
tion (after  Branco). 


Fi«.  1124. 

Nautilus  intermedius  Sowb.     Middle 
Lias :  Hinterweiler,  Würtemberg. 


tetragonal,  reniform  or  hemispherical  outlines.  Never  decidedly  dis- 
coidal, although  the  umbilicus  is  often  open.  More  specialised  forms 
have  a  minute  umbilicus,  and  in  some  cases  it  is  completely  hidden 
during  the  ephebic  stage,  although  invariably  open  in  the  young. 
Zone  of  impression  present  on  the  dorsum  before  the  lohorls  are  in 
contact.  Annular  lobes  often  developed  at  an  early  stage,  but  liable 
to  disappear  in  the  adult ;  absent  in  some  Tertiary  species. 

Genoceras  Hyatt.  Jura.  Gymatoceras  Hyatt.  Cretaceous. 
Eutrephoceras  Hyatt.     Cretaceous  and  Tertiary. 

Nautilus  Linn.  (Figs.  1122-1125).  The  young  resembling 
adults  of  Digonioceras  until  a  late  stage,  and  adults  of  primitive 
species  (like  N.  umbilicatus)  similar  to  Genoceras.  Sutures  slightly 
inflected,  with  faint  ventral  lobes ;  annular  lobes  present.  Volu- 
tions sub-globose,  and  umbilical  Perforation  comparatively  large. 
Siphuncle  centren  in  the  apical  camera,  but  later  becoming  ventrad 
of  centre,     Tertiary  (?)  to  Recent. 


Fio.  1125. 

NmUilns  gcinitzi 
Pictet.  Tithonian  ; 
Stramberg,  Moravia. 


608  MOLLUSCA  phylüm  vi 

Suborder  E.     CYRTOCHOANITES  Hyatt. 

Shells  varying  from  orthoceracones  to  nautilicones,  none  of  them  highly  ornamented, 
although  some  are  annulated  or  costated,  and  in  rare  cases  slightly  nodose.  Sutures  as  a 
rule  simpler  than  in  the  Orthochoanites.  Siphuncle  varies  exceedingly,  passing  from  tubulär 
in  the  young,  and  even  in  the  full-grown  of  primitive  forms,  to  highly  nummuloidal  in  the 
adults  of  specialised  genera,  or  again  in  some  groups  retaining  constantly  its  primitive 
character.  The  funnels,  however,  are  as  a  rule  hent  outward  or  crumpled,  and  generally 
short. 

I.  Annulosiphonata  Hyatt. 

Mostly  orthoceracones  and  cyrtoceracones,  with  a  few  gyroceracones  and  very  rarely 
nautiliconeSj  the  last-named  heing  invariably  discoidal.  Apertures  constantly  open. 
Siphuncle  may  he  empty,  hut  organic  deposits  when  present  always  gathered  about  or 
encrusting  the  funnels  as  hollow  or  solid  internal  rings.  Deposits  sometimes  sujfflcient  to 
form  more  or  less  annulated  endosiphuncles,  the  rings  heing  opposite  the  camerae,  alter- 
nating  with  the  septa,  and  extending  outwardly. 

Family  1.     Loxoceratidae  Hyatt. 

Smooth  orthoceracones  and  cyrtoceracones  similar  to  the  Orthoceratidae^  hut  siphuncle 
distinctly  nummuloidal,  and  funnels  very  short  and  crumpled.  Deposits  not  uncommon, 
hut  irregulär,  and  only  irregulär  endosiphuncles  occasionally  formed. 

Loxoceras  M'Coy  {Sactoceras  Hyatt).  Mostly  orthoceracones,  circiilar  or  elliptical 
in  section.  Siphuncle  supposed  to  be  tubulär  in  the  young,  but  highly  nummuloidal 
in  later  stages,  centren  or  near  the  centre.  Septa  invariably  single,  and  camerae 
empty.     Ordovician  to  Carboniferous. 

Campyloceras  M'Coy  {Aploceras  d'Orb.).  Breviconic  cyrtoceracones  or  orthocera- 
cones with  smooth  or  finely  ridged  shells,  circular  or  depressed  elliptical  in  section. 
Siphuncle  centren  or  ventrad  of  centre.      Carboniferous. 

Family  2.     Uranoceratidae  Hyatt. 

Cyrtoceracones,  gyroceracones  and  nautilicones,  with  stout  volutions.  Siphuncle  in 
primitive  forms  highly  nummuloidal,  hut  invariably  empty ;  in  nautilicones  it  has  less 
nummuloidal  segments,  and  is  uniformly  ventrad  of  centre,  hut  not  near  the  venter. 
Sutures  with  ventral  saddles,  lateral  lohes,  and  also  dorsal  saddles  in  primitive  forms  as 
well  as  the  young  of  all  shells.  Ventral  and  dorsal  lobes  arise  suhsequently  in  the 
ontogeny  of  nautilicones. 

Uranoceras  Hyatt.  Stout,  more  or  less  breviconic  cyrtoceracones,  compressed 
elliptical  or  sub-quadrangular  in  section.  Sutures  with  broad  ventral  saddles,  lateral 
and  dorsal  lobes.  Siphuncle  large,  nummuloidal,  centren  or  ventrad  of  centre. 
Devonian  and  Carboniferous. 

Gigantoceras  Hyatt.  Gyroceracones  similar  to  the  preceding,  but  having  longer 
living  Chambers  and  more  compressed  volutions.  Includes  the  largest  known  Nauti- 
loid  Shells.      Type  G.  (Gyroceras)  inelegans  (Meek).     Silurian. 

Family  3.     Actinoceratidae  Saemann. 

Orthoceracones  and  cyrtoceracones  with  siphuncle  more  or  less  ßlled  hy  rings  of 
organic  deposits,  and  having  an  endosiphuncle  in  the  central  axis.  Camerae  may  he 
empty  or  filled  to  various  degrees  with  organic  deposits,  even  to  the  extent  of  solidifying 
the  entire  shell  previous  to  the  gerontic  stage.  Shells  smooth  or  annulated,  but  not  longi- 
tudinally  ridged,  at  least  in  the  latter  stages. 


CLASS  V 


CEPHALOPODA 


609 


Actinoceras  Bronn.  (Figs.  1126-1127).  Ortlioceracones  and  cyrtoceracones  of  usually 
depressed  elliptical  section,  with  large,  excessively  nummuloidal  siphuncle.  Funnels 
very  short  and  crumpled,  slieath  almost  globular.  In- 
ternal deposits  contracting  tbe  central  axis  into  an 
annulated  endosi])lnincle  with  tubuli  radiating  from  the 
annuli,      Septa  often  double,  with  an  interspace  between 

the  two  layei's  near  the 

siphuncle,  but  solid  near 

the    shell.       Ordovician 

to  Carboniferous. 

Subgenera :       Ormo- 

ceras  Stokes  (Fig.  1128). 


Fig.  1126. 

Actinoceras  cochleatum  (Schloth.)- 
Silurian  ;  Gotland.  Abraded  frag- 
inent  showing  Single  septa  and  tliick 
annulated  endosiphuncle.     1/2. 


Fig.  1127. 

Actinoceras  vertehratum  Hall. 
Silurian  ;  Lockport,  New  York. 
Longitudinal  section  showing 
organic  dei)osits  of  siphuncle 
(after  Barrande). 


Fin.  1128. 

Actinoceras  (Onnoceras)  hayfieldi 
Stokes.  Ordovician ;  Longitudinal 
section  showing  organic  deposits 
of  siphuncle  partly  dissolved  away 
(after  Stokes). 


Ordovician  to  Carboniferous.  Paractinoceras  Hyatt  (Fig.  1129).  Shells  longer  and 
more  slender  tlian  in  the  preceding,  large  siphuncular  segments  confined  to  early 
stages,  and  very  long  living  Chamber.  Type  P.  (Sactoceras) 
canadense  (Whiteaves).     Silurian. 

Gyrtactinoceras  Hyatt.  Type  C.  (Cyrtoceras)  rebelle  (Barr.). 
Deiroceras  Hyatt;  Huronia  Stokes  (Fig.  1130);  Discosorus 
and  Gonioceras  Hall.     Silurian. 

(?)  Tretoceras  Salter.  Orthocera- 
cones  having  a  centren  nummuloidal 
siphuncle,  similar  to  that  of  Acti- 
noceras but  smaller,  and  with  a 
superficial  tulnilar  siphuncle  (so- 
called),  having  very  long  but  not 
Holocho.anoidal  funnels.  Sheath  not 
yet  shown  to  be  present.  It  is  pos- 
sible  that  the  structure  referred  to 
is  a  peripheral  pseudo  -  siphuncle 
formed  by  abnormal  condition  of  the 
septa.     Silurian. 


Fi(i.  1J2; 


Actinoceras  (Faractinoceras) 
docens  (Barr.)  Silurian  (B); 
Dvoretz,  Bohemia.  Vertical 
section  showing  senile  stage 
without  organic  deposits, 
prcceded  by  adult  stage  with 
siphuncular  rosettes  (after 
Barrande). 


Fig.  1130. 

Huronia  vertebralis 
Stokes.  Ordovician;  Isle 
Drummond,  Lake  Hui"on. 
Siphuncle. 


II.  AcTiNOSiPHONATA  Hyatt. 


OrthoceraconeSy         cyrtoceracones^ 

gyroceraconeSj    and    a   few    discoidal 

nautilicones.     Shells  frequently  hreviconic,  in  which  case  the  gerontic  living  Chambers  and 

apertures  are  more  highly  contractecl  than  in  all  other  Nautiloids.     Siphuncle  sometimes 

empty ;  organic  deposits,  ivhen  present 

VOL.  I 


the  form  of  laminae  radiating  from  the  sheath 

2  R 


610 


MOLLUSCA 


PHYLUM  VI 


0/  each  Segment  towards  the  interior.  These  internal  calcareous  septa  are  united  only  in 
their  peripheral  parts,  not  meeting  at  the  central  axis  so  far  as  known,  and  also  liahle 
to  he  more  or  less  interrupted  in  the  transverse  plane  of  each  funnel.  The  interior  is 
consequently  an  actiniform  endosiphuncle  with  rays  extending  outivardly  hetween  the 
laminae  of  the  deposits. 

Family  4,     Jovellanidae  Hyatt. 

Orthoceracones  and  cyrtoceracones  ivith  slightly  compressed  oval,  or  depressed  and 
more  or  less  sub-trigonal  sections.  Shells  smooth  or  partially  annulated.  Siphuncle  large, 
with  well-developed  actiniform  lamellae,  and  distinct  endosiphuncles.  Apertur e  open  and 
living  Chamber  uncontracted  in  the  gerontic  stage. 

Includes  Jovellania  Bayle ;  and  Tripleuroceras  Hyatt.  Silurian  and  Devonian. 
Mixosiphonoceras  Hyatt.  Type  M.  (Oyrtoceras)  desolatum  (Barr.).  Silurian  and 
Devonian.     Projovellania  Hyatt.     Type  P.  {Gyrtoceras)  athleta  (Barr.).      Silurian. 


Family  5.     Rizoceratidae  Hyatt. 

Orthoceracones  and  cyrtoceracones  expanding  regularly  hy  growth  throughout  life,  the 
living  chamher  very  slightly  or  not  sensihly  contracted  in  the  gerontic  stage.  Aperture  con- 
stantly  open,  and  with  slight  dorsal  as  well  as  somewhat  deeper  and 
hroader  hyponomic  sinuses.  Siphuncle  generally  small  and  empty, 
hut  actiniform  lamellae  and  an  endosiphuncle  sometimes  occur. 
Shells  as  a  rule  smooth  or  with  transverse  hands  only,  hut  longitu- 
dinal  Striae  are  often  present  in  earlier  stages. 

Rizoceras  Hyatt  (Fig.  1131).  Orthoceracones  and  exo-  or 
endogastric  cyrtoceracones  liaving  circular  or  elliptical  sections. 
Living  Chamber  extraordinarily  large  and  long  as  compared  with 
camerated  part.     Silurian  to  Carboniferous. 

Gyrtorizoceras  Hyatt.  Sections  more  com- 
pressed than  in  Rizoceras,  living  Chamber 
shorter  and  apt  to  be  more  or  less  laterally 
compressed  in  gerontic  stage,  but  the  dorso- 
ventral  diameters  only  very  slightly  so  or  not 
at  all.  Sutures  more  sinuous,  and  with  decided 
ventral  and  dorsal  saddles.  Type  G.  (Gyrtoceras) 
minneapolis  (Clarke).  Ordovician  and  Silu- 
rian. 


Rizoceras  robustum 
(Barr.).  Silurian  (E) ; 
Bntowitz,  Bohemia. 
Aperture  open.     1/2. 


Family  6.     Ooceratidae  Hyatt. 

Orthoceracones   and    gyroceracones    with   closely    set   septa  and  j,^if,_  1x32. 

large  nummuloidal  siphuncle  in  later  stages  of  the  ontogeny,  hut  ooceras      (Gyrtoceras) 

tuhular  in  the  young.     Actiniform.  deposits  oftener  present  than  in  bayhi  (Barr.).    Silurian 

,-„.             ^•7        7,        j.                T       ry           1                      .77                 .  (E) ;  Lochkow,  Bohemia 

the  Rizoceratidae,  out  not  general.     Jiunnels  very  variable,  sometimes  (after  Barrande). 

minutely  plicated  or  hooh-like  in  section,  confined  to  dorsal  side  of 
tuhe,  or  sometimes  ahsent  altogether.      Living  chamher  short   and  lihe  that    of  Gyrto- 
rizoceras;  aperture  not  infrequently  sub-trigonal  in  outline,  hut  alivays  open. 

Ooceras  Hyatt  (Oonoceras  Hyatt)  (Fig.  1132),  Cyrtoceracones  more  elongated 
and  usually  more  compressed  than  in  Gyrtorizoceras,  but  otherwise  similar  except  in 
structure  of  the  siphuncle.  Septa  rise  rapidly  on  ventral  side,  and  may  bend  sharply 
orad,  forming  a  funnel   ridge   or    Shoulder    on  that    side,  but    disappearing  on   the 


CLASS  V  CEPH ALOPOD A  6 1 1 

opposite  side  of  tlie  saiiie  funiiel.     When  the  funnel  itself  is  absent,  the  ridges  look 
like  reversed  funnels  or  collars.     Silurian. 

Gyrtoceras  Goldf.  Large  exogastric,  breviconic  cyrtoceracones  ;  sections  depressed 
elliptical  or  approximating  to  trigonal,  the  dorsum  more  or  less  flat,  and  venter 
elevated.  Apertiire  contracted  in  gerontic  stage  to  a  T-shaped  opening,  and  placed  at 
an  acute  angle  witli  the  central  axis,  so  that  the  dorsal  side  is  very  miicli  shorter  than 
the  ventral.  Siphuncle  large,  nummuloidal,  with  well-developed  actiniform  lamellae, 
and  with  an  endosiphuncle  in  later  stages  of  ontogeny.     Devonian. 

Family  7.     Oncoceratidae  Hyatt. 

Ä  phylogerontic  group  of  breviconic  orthoceracones  and  cyrtoceracones  similar  to 
Cyrtorizoceras,  but  shells  much  shorter  and  living  Chamber  usually  contracted,  especially 
in  their  transverse  diameters  during  the  gerontic  stage.  Siphuncle  tubulär  or  highly 
nummuloidal,  without  deposits. 

Eremoceras  Hyatt.  Cyrtoceracones  similar  to  Gyrtorizoceras,  but  living  Chambers 
longer,  and  aperture  more  or  less  flaring  and  open.  Siphuncle  more  or  less  nummu- 
loidal.    Type  E.  (Gyrtoceras)  syphax  (Bill.).     Ordovician. 

Gyclostomiceras  Hyatt.  Slender,  short,  exogastric  orthoceracones  and  cyrtocera- 
cones, circular  or  compressed  in  section.  Living  Chamber  as  compared  with  camerated 
part  longer  and  larger  than  in  most  forms,  less  contracted,  and  with  open  aperture  in 
gerontic  stage.     Type  G.  {Gomphoceras)  cassinense  (Whitf.).     Ordovician  to  Devonian. 

Oncoceras  Hall.  Compressed  exogastric  cyrtoceracones  with  sections  like  Gyrtori- 
zoceras, but  Shells  as  a  rule  much  shorter  and  smaller,  and  siphuncle  more  distinctly 
nummuloidal.  Living  Chamber  also  more  flattened  laterally,  the  aperture  elongated 
and  often  sub-trigonal,  but  typically  open.     Ordovician. 

Subgenus :  Meloceras  {Melonoceras)  Hyatt.  Similar  to  the  last,  but  lateral  edges 
of  the  gerontic  aperture  grow  inwards,  and  form  pear-shaped  outlines.     Silurian. 

Family  8.     Poterioceratidae  Foord. 

Smooth,  breviconic  orthoceracones  and  cyrtoceracones  having  circular  or  depressed 
elliptical  sections.  Gerontic  aperture,  except  in  primitive  forms,  is  contracted  and  apt  to 
issume  a  sub-trigonal  outline;  it  is  laterally  narrowed  and  approximates  those  of  the 
lext  family  only  in  Streptoceras.  Outlines  of  aperture  entire ;  sutures  straight  or  only 
kightly  sinuous.  Siphuncle  in  this  and  remaining  families,  so  far  as  knoum,  slightly 
mmmuloidal  and  empty  in  the  young,  but  becomes  larger ;  in  specialised  forms  it  is  apt 
be  more  or  less  filled  with  radiating  lamellae,  and  in  late  stages  has  an  endosiphuncle. 

Glinoceras  Mascke.     Ordovician  to  Devonian.     Sycoceras  Pictet.     Devonian. 

Poterioceras  M'Coy  (Apioceras  Fischer  ;  Äcleistoceras  Hyatt).     Orthoceracones  and 

exogastric  cyrtoceracones,  short  and  stout,  with  sub-trigonal  gerontic  aperture.     Brachial 

krea  not  decidedly  differentiated  from  the  hyponomic  sinus,  and  contraction  may  take 

)lace  in  all  diameters  or  more  extensively  in  the  lateral.     Ordovician  to  Carboniferous. 

Streptoceras  Bill.  Like  the  last  but  more  arcuate,  with  laterally  contracted 
iperture,  and  a  short  hyponomic  sinus  distinct  from  the  brachial  area.     Silurian. 

Family  9.     Trimeroceratidae  Hyatt. 

Smooth  breviconic  orthoceracones  and  cyrtoceracones  similar  to  Poterioceras  in  aspect 
md    sutures,  but    more  slender,  eqjecially  in  the  young,  and  aperture  very  distinct  in 
imitive  forms.     Even  the  latter  usually  have  the  brachial  distinctly  marked  of  from 
fhyponomic  area  by  ingrowth  of  sides  of  the  aperture,  and  in  all  specialised  shells  the 


612 


MOLLUSCA 


PHYLÜM  VI 


hyponomic  sinus  and  special  inflections  known  as  "  brachial  sinuses  "  are  formed  by  bases 
of  the  arms  on  edges  of  the  brachial  area.  Finally,  the  aperture  becomes  reduced  to  a  more 
or  less  Y-  or  T-sha])ed  figure,  with  an  open  semicircular  sinus  at  the  end  of  the  hyponomic 
slit  or  area,  and  similar  sinuses  in  the  edges  of  the  brachial  slit,  corresponding  to  the 
number  of  arms.     Silurian. 

Mandaloceras  Hyatt  (Dimorion  Barr.)  (Fig.  1133).  DifFers  from  Poterioceras  in 
the  gerontic  aperture,  wliich  is  laterally  contracted,  and  has  hyponomic  and  brachial 
areas  distinctly  differentiated  in  all  but  the  most  primitive  species.  More  specialised 
forms  have  these  areas  narrowed  down,  but  special  sinuses  are  not  formed. 

Trimeroceras  Hyatt  (Trimorion,  Trimeres  Barr.) ;  Pentameroceras,  Septameroceras 
Hyatt.  Silurian.  Aperture  in  the  first  has  a  median  and 
two  brachial ;  in  the  second  a  median  and  four  brachial ; 
and  in  the  last  a  median  and  six  brachial  sinuses. 


Mandaloceras  (Gomphoceras)  bohemicum  (Barr.).     Silurian  (Etage  E) ; 
Dvoretz,  Bohemia.     A,  Side  view  of  conch.     B,  Aperture. 


Fig.  1134. 

Tetrameroceras  panderi 
(Barr.).  Silurian  (E) ;  Dvoretz, 
Boliemia.     i/j  (after  Barrande). 


Hemiphragmoceras  Hyatt.  Compressed  endogastric  cyrtoceracones  having  a 
narrowed  hyponomic  area  like  Phragmoceras,  but  with  brachial  areas  as  in  Dimeroceras. 
Type  H.  (Phragmoceras)  pusillum  (Barr.). 

Tetrameroceras  Hyatt  {Tetramorion,  Tetrameres  Barr.)  (Fig.  1134).  Like  the  last, 
but  with  more  highly  contracted  aperture  and  four  lateral  sinuses. 

Hexameroceras  Hyatt.  Brachial  area  with  six  lateral  sinuses.  Octameroceras 
Hyatt.     Brachial  area  with  eight  lateral  sinuses.     Type  0.  {Phragm.)  callistoma  (Barr.). 


Family  10.     Phragmoceratidae  Hyatt. 

Smooth  breviconic  cyrtoceracones  and  gyroceracones  rapidly  expanding  by  growth  in 
their  dorso-ventral  diameters,  and  having  open  apertures  only  in  primitive  types  or  the 
young  and  ephebic  stages  of  more  specialised  forms.  In  the  latter  gerontic  apertures  are 
laterally  contracted  and  have  a  very  long  hyponomic  area  terminated  by  a  large 
hyponomic  sinus.  The  brachial  area  may  be  more  or  less  open  and  ellijjtical,  or 
narrowed  and  transversely  elongated,  but  always  has  an  entire  outline.  Siphuncle 
generally  large,  nummuloidal,  and  often  has  actiniform  lamellae  and  endosiphuncles  in 
later  stages.     Shells  mostly  endogastric. 

Godoceras  Hyatt.  Excessively  short  and  rapidly  expanding  cyrtoceracones  like 
some  species  of  Rizoceras,  but  with  large  living  Chambers,  narrow  venter,  and  large 
siphuncle  just  ventrad  of  centre.  Aperture  constantly  open.  Type  G.  (Gyrtoceras) 
domitum  (Barr.).     Silurian. 

Protophragmoceras  Hyatt  (Fig.  1135).     Similar  to  the  last,  but  form  more  com- 


CLASS  V 


CEPHALOPODA 


613 


l)ressed,  and    sipliuiicle   iiear   the   venter    (internal).     Ditfers   from   Phragmoceras   in 
having  aperture  open  throughout  life.     Type  P.  {Cyrtoceras) 
murchisoni  (Barr.).     Silurian. 

Gomphoceras  Sowb.  Stout  short  orthoceracones  and 
cyrtoceracones  similar  to  some  species  of  Phragmoceras,  but 
straighter,  stouter  and  less  conipressed  in  form,  and  gerontic 
aperture  less  contracted  laterally.  Hyponomic  siniis 
sh orter,  and  curvature  exogastric.     Ordovician  and  Silurian. 

Phragmoceras  Sowb.  (Figs.  1136,  1137).  Compressed 
endogastric  cyrtoceracones  and  gyroceracones,  oval  in 
section,  and  venter  narrowly  roiinded.  Siphuncle  large 
and  near  the  venter  (internal).  Gerontic  aperture  much 
contracted  laterally,  the  hyponomic  area  very  long  and 
narrow.     Silurian. 


Incertae  Sedis. 


Fifi.  1135. 


Nothoceras  Barr.  Represented  by  the  single  species  N.  rrotc/pliragmoceras  murchisoni 
hohemicum  Barrande,  in  which  the  septum  turns  orad,  SSJ^kL,  bSL.  ^^Vr**  ^^ ' 
forming   an   inverted   funnel.       This   funnel  connects   with 

a  more  or  less  inflated  sheath  that  closed  the  siphuncle,  and  connected  it  with  the 
distal  opening  of  the  next  succeeding  septum,  thus  completely  reversing  the  relative 
positions  of  funnels  and  sheaths  in  other  forms.      The  appearances  as  described  by 


^r^ 


Fig.  1130. 

Phragmoceras  hroderipi  Barr.     Silurian  (^tage  E)  ;  Lochkow,  Bohemia. 

1/2  (after  Barrande). 


Fio.  1137. 

Phragmoceras  loreni 
Barr.  Silurian  (E) ;  Loch- 
kow, Bohemia.  Section 
showing  laniellar  organic 
deposits  (ait«r  Barrande). 


Barrande  are  not  deemed  suflficient  to  prove  the  truth  of  this  statement,  and  it  is 
unsafe  to  accept  it  absolutely  until  the  development  has  been  studied.  The  cavity  is 
divided  by  radiating  lamellae  running  longitudinally  as  in  the  Actinosii)honata. 


614  MOLLUSCA  phylüm  vi 


Range   and   Distribution   of  the   Nautiloidea. 

Fossil  Nautiloidea  have  been  recorded  by  Billings  as  occurring  in  Canada  earlier 
than  tlie  Quebec  Group,  but  bis  statement  lacks  confirmation.  An  abundant  Ceplialo- 
podan  fauna  makes  its  appearance  in  tlie  earliest  Quebec  or  Calciferous,  and  is  quite 
distinct  from  other  later  assemblages,  JJiphragmoceras  and  otber  ortboceracones  and 
cyrtoceracones  with  very  peculiar  sipbuncles  occur  here,  but  gyroceracones  and  nautili- 
cones  are  absent.  However,  the  information  we  have  at  present  of  this  fauna  is 
limited,  and  but  few  positive  conclusions  can  be  drawn. 

All  the  suborders  of  Nautiloidea  are  initiated  in  the  Ordovician,  and  one  of  them, 
^chistochoanites,  is  confined  to  this  period.  Holochoanites  and  Mixochoanites  become 
extinct  in  the  Silurian,  and  only  Orthochoanites  survive  the  Paleozoic.  The  sub- 
orders that  disappear  at  this  early  date  are  remarkable  for  their  complicated  siphun- 
cular  structure,  and  peculiar  sigmoidal  septa  observed  in  the  gerontic  living  Chambers 
of  certain  forms  (Äscoceras,  Gonioceras),  while  their  prevailing  habit  is  gyroceraconic. 
The  sigmoidal  septa  do  not  become  complicated  in  correlation  with  closer  coiling  of  the 
Shell,  but  occur  in  cyrtoceracones  correlating  with  highly  compressed  cones,  and  in 
ortboceracones  correlating  with  strongly  depressed  cones. 

The  older  classifications  recognised  the  straight  ortboceracones,  curved  cyrtocera- 
cones, loosely  coiled  gyroceracones,  and  more  closely  coiled  nautilicones  as  distinct 
natural  divisions.  Although  it  is  possible  to  employ  the  habit  of  curvature  in  con- 
junction  with  family  groups  as  a  convenient  means  for  tracing  laws  of  distribution  and 
the  like,  yet  for  more  accurate  data  the  genera  must  be  considered  independently. 
For  instance,  some  families  made  up  largely  of  gyroceracones  and  nautilicones  also 
contain  a  few  ortboceracones  and  cyrtoceracones,  and  these  have  to  be  neglected  in 
estimating  the  relative  proportions  of  straight  and  coiled  conchs.  Other  sources  of 
error  are  presented  by  sporadic  uncoiled  or  gerontic  forms  whicli  occur  in  families 
having  coiled  shells.  In  a  general  way,  however,  it  is  possible  to  state  the  morphic 
succession  as  follows  : — 

Ortboceracones,  together  with  their  almost  invariably  associated  cyrtoceracones 
exceed  gyroceracones  in  the  Quebec  in  the  proportion  of  three  families  to  one,  and  this 
horizon  contains  but  one  family  of  closely  coiled  nautilicones,  and  one  of  the  uncoiled 
or  gerontic  type.  In  the  Ordovician  are  found  no  less  than  fourteen  families  having 
straight  or  approximately  straight  shells,  as  against  seven  families  of  gyroceracones  and 
nautilicones.  Thereafter  until  toward  the  close  of  the  Paleozoic,  the  proportions  of 
straight  and  coiled  forms  remain  approximately  equal.  The  Permian  has  but  one 
surviving  family  of  ortboceracones,  and  four  of  the  coiled  groups  ;  in  the  Trias  the 
ratio  is  one  to  six,  and  in  the  Jura  coiled  forms  alone  persist.  Thus,  a  slowly  working 
tendency  is  apparent,  leading  to  the  production  of  more  and  more  closely  coiled  cones, 
and  the  elimination  of  straight  and  slightly  curved  forms.  Gyroceracones  disappear 
with  the  Carboniferous,  and  the  more  discoidal  nautilicones  with  the  Trias. 

Some  Gurions  features  are  presented  by  the  phylogerontic  or  uncoiled  shells.  Only 
one  family,  the  Silurian  Lituitidae,  have  all  the  genera  uncoiled  save  the  probable 
ancestral  close-coiled  type.  Other  families  have  isolated  genera  or  species  exhibiting 
similar  tendencies,  and  becoming  partially  uncoiled  during  their  later  stages,  although 
close-coiled  in  the  young.  Such  forms  occur  throughout  the  Devonian,  but  none  have 
yet  been  found  in  the  Carboniferous,  where  uncoiling  of  the  volutions,  when  it 
occurred,  took  place  earlier  than  the  gerontic  stage.  From  the  Mesozoic  and  later 
horizons,  no  species  is  known  in  which  the  gerontic  stage  is  to  the  slightest  degree 
uncoiled. 

Torticones  are  more  aberrant  than  any  other  conchs,  and  may  be  best  classified  as 
phylogerontic  forms,  since  tendencies  toward  unsymmetrical  development  of  the 
volutions  occur  in  the  gerontic  stage,  and  are  genetic  in  but  a  few  genera,  where  they 


CLAss  V  CEPHALOPODA  615 

r 

appear  during  tlie  early  stages  and  are  preceded  so  far  as  known  by  a  symmetrical 
volutioii.  The  first  manifestation  of  torticones  is  in  the  Ordovician,  and  tlieir  acme  is 
attained  during  tlie  Silurian.  As  regards  ornanientation,  annnlated  shells  appear  in 
the  Calciferous,  and  those  with  longitudinal  ridges  later  in  the  Ordovician,  together 
with  tiiberciilated  and  costated  gyroceracones  and  nantilicone.s.  The  last-named,  how- 
ever,  are  nuich  more  abimdant  in  the  Devonian  and  Carbon iferous,  after  which  they 
disappear.  Very  higlily  ornaniented  shells  exist  in  the  Trias,  but  following  this 
period  the  conchs  are  smootli. 

Very  striking  is  the  marvelloiisly  sudden  rise  of  the  Nautiloidea  as  a  gi'oup, 
reaching  its  maximiim  in  the  Silurian,  and  followed  by  a  decline  extending  from  the 
Devonian  to  the  Trias.  Then  the  forces  acting  unfavourably  upon  their  existence 
were  arrested,  or  their  violence  lessened,  and  the  group  has  been  affected  by  only  very 
sliglit  changes,  and  an  exceedingly  slow  process  of  retrogression  until  the  present  time. 
The  acme  of  siphuncular  differentiation  occurred  in  the  Ordovician,  of  general  morphic 
diversity  in  the  Silurian,  of  ornamentation  in  the  Devonian,  and  of  sutures  in  the 
Trias. 

Geographically  considered,  some  facts  of  distribution  are  of  general  interest.  The 
fauna  of  the  Quebec  or  Calciferous,  which  in  Newfoundland,  Canada,  Vermont,  and 
the  vicinity  of  Poughkeepsie,  New  York,  is  rieh  in  fossil  remains,  is  represented  by 
a  few  camerated  conchs  in  the  Durness  Limestone  of  Scotland.  Holochoanites  and 
Schistochoanites  'are  most  plentifully  represented  in  the  American  faunas,  but  Mixo- 
choanites  very  sparsely  so,  at  least  as  compared  with  the  Oi-dovician  and  Silurian  of 
Bohemia.  The  same  is  true  of  the  Lituitidae,  Ophidioceratidae  and  Hercoceratidae 
among  Orthochoanites,  and  of  the  Jovellanidae,  Trimeroceratidae,  and  kindred  families 
among  the  Cyrtochoanites.  The  Devonian  and  Carboniferous  faunas  of  America 
and  Europe  are  nearly  on  a  par,  but  the  Permian  of  the  western  hemisphere  is 
very  deficient  in  Nautiloid  remains.  The  Jurassic  faunas  of  America  have  so  far 
yielded  but  one  specimen  of  a  Nautiloid,  but  they  were  probably  present  to  some 
extent,  since  they  are  represented  in  the  Cretaceous  of  this  country.  During  the 
Cretaceous  and  Tertiary  the  principal  distribution  of  the  Nautilidae  was  in  the 
eastern  hemisphere,  and  the  last  surviving  species  of  Nautilus  are  now  restricted  to 
oriental  waters.  The  following  table  shows  the  ränge  of  the  leading  Nautiloid 
families. 

[The  systeniatic  portion  of  the  foregoing  chapter  on  Nautiloidea  was  revised  for  the  first 
edition  of  this  work  by  tlie  late  Professor  Alpheus  Hyatt.  In  the  earlier  edition  some  nine- 
teen  new  genera  of  fossil  Nautiloids  were  proposed  by  Professor  Hyatt,  as  well  as  many  new 
genera  of  Ammonoids.  The  type  species  of  these  new  genera  were  designated,  but  tlie  author's 
intention  to  publish  suitable  generic  diagnoses  has  remained  for  the  most  part  unfulfilled. 
—Editor.] 


[Tablk 


616  MOLLUSCA 

* 

Table  showtng  Vertical  Range  of  the  Nautiloidea. 


PHYLÜM  VI 


Families. 

c 
.2 

o 

.g 

CO 

CS 

2 
Vi 

1 
1 

.2 
1 

CS 

i  s 

2 

1-5 

i 
1 

1 

1 

A.  HOLOCHOANITES 

1.  Dipliragmidae  . 

2.  Endoceratidae  . 

3.  Cyrtendoceratidae     . 

B.  MiXOCHOANITES 

1.  Ascoceratidae   . 

2.  Mesoceratidae  . 

C.  SCHISTOCHOANITES 

D.  Orthochoanites 
1.  Orthoceratidae . 

— 

— 

— 



2.  Cycloceratidae  . 

3.  Kionoceratidae 

4.  Tarphyceratidae 

5.  Trocholitidae    . 

6.  Plectoceratidae 

7.  Ophidioceratidae 

8.  Lituitidae 

9.  Grypoceratidae 

10.  Clydonautilidae 

11.  Halloceratidae  . 

12.  Ryticeratidae    . 

13.  Rhadinoceratidae 

14.  Trigonoceratidae 

15.  Triboloceratidae 

16.  Rhineceratidae 

17.  Hercoceratidae  . 

18.  Tainoceratidae . 

19.  Centroceratidae 

20.  Pleuronautilidae 

21.  Koninckioceratidae 

22.  Solenocheilidae 

23.  Estonioceratidae 

24.  Nautilidae 

! 

i 



— 



— 

_^^ 

„^^ 

_^_ 



— 





^ 

i 



E.  Cyktochoanites 
1.  Loxoceratidae   . 

,. 

2.  Uranoceratidae 

3.  Actinoceratidae 

4.  Jovellanidae      . 

5.  Rizoceratidae    . 

6.  Ooceratidae 

7.  Oncoceratidae   . 

8.  Poterioceratidae 

9.  Trimeroceratidae 

10.   Phragmoceratidae      . 

• 

— 

__. 

.__ 

1. 

1 

— 

! 

ii 

!     1 

CLAss  V  .   GEPHALOPODA  617 


Order  2.     AMMONOIDEA  Zittel.i 

Shells  similar  io  ihose  of  the  Nautiloidea  in  some  primitive  Paleozoic  groups,  hut 
these  give  rise  to  others  with  mwe  highly  ornamenied  shells,  the  apertures  of  which 
have  ventral  rostra  instead  of  hyponomic  sinuses.  Sutures,  as  a  rule,  have  ventral 
lobes  in  the  later  stages  of  ontogeny  ;  the  inßedions  become  more  numerous  than  in 
Nautiloids  even  in  Paleozoic  genera,  and  their  outlines  during  the  Mesozoic  are 
cxtremely  complex.  Siphuncle  invariahly  small,  and  (except  in  the  Clymeniidae) 
situated  near  the  venfer.  Funnels  short,  retrosiphonate  in  primitive  forms,  hut 
becoming  sometimes  pirosiphonate  during  the  Paleozoic,  and  as  a  rule,  prosiphonate 
during  the  Mesozoic. 


The  ontogeny  begins  with  a  calcareous  protoconch,  the  apical  stage  of  the 
conch  being  an  open  neck  built  in  continuation  of  the  permanent  aperture  of 
the  protoconch.  The  first  septum  is  concave  as  in  Nautiloids,  and  sutures  are 
straight  or  have  more  or  less  of  a  saddle  on  the  venter.  Young  stages  of 
Mesozoic  shells  recapitulate  the  primitive  adult  characters  of  Paleozoic  forms. 
The  aperture  was  closed  when  the  animal  was  retracted  by  a  single  horny  plate 
(anaptychus)  or  a  pair  of  calcareous  plates  (aptychis),  probably  secreted  by 
muscular  lobes  homologous  with  the  hood  in  Nautilus. 

Shell  Characters. — There  are  apparently  no  characters,  not  even  the  presence 
of  a  calcareous  protoconch,  which  can  be  relied  upon  to  separate  Bactrites  from 
the  orthoceraconic  Nautiloids.  Nevertheless,  the  position  of  the  siphuncle  and 
its  peculiar  funnels  are  features  which  seem  to  place  this  form  with  true 
Paleozoic  Ammonoids.  There  is  but  one  series  of  straight  shells  among 
Ammonoids,  and  these  are  obviously  not  the  same  as  orthoceracones,  but  are 
more  properly  called  bactriticones  (Fig.  1169).  Similarly,  the  loosely  coiled 
Mimoceras  shells  (Fig.  1170)  are  not  gyroceracones,  but  only  their  morphic 
equivalents  in  a  different  genetic  stock  ;  hence  the  term  mimoceracone  should 
be  substituted  for  gyroceracone.  In  the  same  sense  the  closely  coiled  sym- 
metrica! Shells,  comparable  in  external  aspect  and  intimate  structure  with 
nautilicones,  should  be  described  among  Ammonoids  as  ammoniticones.  The 
term  torticone,  however,  can  be  conveniently  applied  to  both  groups,  since  it 
does  not  connote  any  special  structures,  but  is  a  general  name  for  all  asym- 
metrical  spirals. 

Ammoniticones  in  some  Paleozoic  forms  are  mimoceracones  during 
nepionic  stages,  and  consequently  in  later  stages  a  Perforation  is  present 
passing  through  the  umbilicus  as  in  Nautiloids.  However,  in  most  Paleozoic 
and    all  later  ammoniticones,  the  coiling  is  so  close  even  at  the  beginning 

^  Besides  the  works  cited  the  followhig  nmy  be  coiisulted  : — Buckman,  S.  S.,  Divisions  of  so- 
caUed  Jurassic  Time.  Quar.  Jonrn.  Geol.  Soc,  1898,  vol.  Uw—Clarke,  J.  M.,  The  Naples  Fauna. 
16th  Ann.  Rep.  N.Y.  State  Geologist,  1898.— CVicyfc,  G.  C,  Muscular  Attachment  of  the  Animal 
to  its  Shell  in  Animonoidea.  Trans.  Linn.  Soc,  1898,  ser.  2,  vol.  vü.—Haug,  £.,  Etudes  sur  les 
Goniatites.  Mem.  Soc.  Gt'ol.  Frunce,  Paleont.,  1898,  vol.  \n.—Levi,  ('.,  Fossili  degli  strati  a 
Terebratula  aspasia.  Boll.  Soc.  Geol.  Italia,  1895,  vol.  xv.—Parona,  C.  F.,  and  Bonarelli,  O., 
Faune  du  Callovien  inferieur  (Chanazien)  de  Savoie.  Mem.  Acad.  Savoie,  1897,  vol.  vi.— Semenoff,  B., 
Anwendung  der  statistischen  Methode  zum  Studium  der  Vertheilung  der  Ammoniten.  Ann.  Geol. 
Mineral.  Russie,  1897,  vol.  il— Smith,  J.  F.,  Development  of  Lytocerasand  Pliylloceras.  Proc.  Calif. 
Acad.  Sei.,  1898,  vol.  \.~-Choffat,  P.,  Les  Ammonees  du  Bellasien,  des  Conches  a  Neolobites  Vibra- 
yeanus,  du  Turonien  et  du  Senonien.  Faune  cret.  du  Portugal,  1898,  ser.  2,  vol.  n.—Jackson,  lt.  T., 
Localised  Stages  of  Development  in  Plauts  and  Animals.  Mem.  Boston  Soc.  Nat.  Hist.,  1899,  vol.  v. 
— Novak,  J.,  Untersuchungen  über  die  Cephalopoden  der  oberen  Kreide  in  Polen.  II.  Die  Scaphiten. 
Bull.  Acad.  Sei.  Cracovie,  ser.  B,  1911. 


618 


MOLLUSCA 


PHYLUM  VI 


of  the  conch,  that  the  protoconch  is  closely  enwrapped  by  the  first  volution, 
and  no  Perforation  is  visible  even  under  a  magnifier.  There  are  two  pits, 
however,  one  on  either  side  of  the  apical  end  of  the  conch,  which  remain  as 
remnants  of  this  Perforation,  and  are  present  in  all  ammoniticones  (except 
perhaps  certain  Clymeniidae).  The  bactriticone  obviously  represents  the 
primitive  or  primary  radical  of  the  Ammonoidea,  and  the  mimoceracone  the 
next  or  secondary  radical  of  this  Order. 

Ammoniticones  of  the  Nautilinidae  introduce  a  peculiar  form  of  volution, 
the  anarcestean  (Fig.  1171),  which  is  depressed  and  crescentic  in  section,  and 
may  be  regarded  as  an  ancestral  radical.  These  f  orms  evolve  a  series  becoming 
more  involute  and  compressed  (Fig.  1172),  and  some  with  elevated  or  narrow 
venters  and  well-defined  lateral  zones  (Fig.  1173),  but  still  retaining  in  the 
young  more  or  less  of  the  anarcestean  aspect.  The  Clymeniidae  have  a  few 
radical  forms  of  similar  aspect  and  with  somewhat  similar  sutures  (Fig.  1165) ; 
they  then  produce  a  series  of  compressed  discoidal  shells  having  cordiform  or 
quadrate  sections  (Figs.  1166-1168),  and  these  also  develop  involute  forms 
among  specialised  species.  The  Gephyroceratidae  and  Beloceratinae  have  a 
similar  history,  but  in  the  Glyphioceratidae  coronate  or  gastrioceran  forms  with 
trapezoidal  section  and  broad  venter  become  common  in  the  ephebic  stages 
(Fig.  1196).  In  the  more  specialised  groups,  the  anarcestean  character  re- 
appears  only  during  the  young  stages. 

Phylogeronetic  series  (Bhabdoceras,  Cochloceras)  make  their  appearance  in  the 
Upper  Trias,  become  more  abundant  in  the  Jura,  and  still  more  important 
during  the  Cretaceous.  They  have  their  own  peculiar  radicals,  sometimes 
found  among  discoidal  and  again  among  more  involute  shells,  but  for  the 
most  part  they  do  not  originate  from  smooth  shells. 

The  same  descriptive  terms  are  used  for  shell  characters  among 
Ammonoids  as  among  Nautiloids.     Obviously  the  first   stage  of  the  conch 


Fig.  1138. 

Asellate  protoconch  of  Gephyroceras  calculi- 
forme  (Beyr.).  Upper  Devon ian ;  Büdesheim, 
Bifel.  A,  viewed  from  in  front.  B,  From  the 
side  (after  Branco). 


Fig.  1139. 

Latisellate  stage  of  Ärcestes  cymhiformis  (Wulfen). 
Trias  ;  Anssee,  Austria.  A,  Viewed  from  in  front. 
B,  From  the  side  (after  Branco). 


was  that  of  a  living  Chamber,  the  protoconch  being  without  internal  septa 
or  siphuncle  (Fig.  1150).  Then,  after  building  out  the  usually  flattened 
neck  or  apical  part  of  the  conch,  the  animal  rested,  and  the  first  septum  as 
well  as  the  caecum  (or  incipient  stage  of  the  siphuncle)  was  secreted.  The  first 
septum  closed  the  aperture  of  the  protoconch,  and  the  caecum  projected  into 
its  interior.  The  caecum  is  connected  with  the  internal  surface  of  the  proto- 
conch by  bands  (Figs.  1150,  1151);  or  semiconical  prolongations,  described 
by  Munier-Chalmas  as  the  prosiphon.  But  these  bands  are  of  various  shapes, 
are  not  connected  with  the  interior  of  the  caecum,  and  appear  to  be  merely 


CLASS  V 


CEPHALOPODA 


619 


Fig.  1140. 

Angustisellate  stage  of  Phyllocercwi 
heteropJiyllum  (Sowb.).     Lias. 


calcareous    supports  for   the   bottom   of  the  caecum.     The   earliest  sutures, 

desci'ibed  in  a  masterly  way  by  Branco,  are  divided  by  him  into  thiee  classes : 

asellate,    latisellate    and    angusfisellate    (Figs. 

1138-11 40).    The  asellate  cross  the  venter  as 

a  straight  line  or  very  slight  saddle,  and  are 

present  only  in  the  ephebic  stages  of  Cyrto- 

chjmeniaCl)  and  in  the  young  mimoceran  stage 

of  the  Nautilinidae.     In  all  except  primitive 

forms   it   is    confined  (as   are   most    of    the 

purely  nautiloidean  characters)  to  the  first 

septum.     The  latisellate  stage  is  character- 

ised    by    a    decided    broad    saddle    on    the 

venter,  with  corresponding    deeper    and    broader    lobes    on  the  sides.      The 

angustisellate    stage    has    prominent,    sometimes    almost    sub- acute    ventral 

saddles  with  corresponding  deep  lateral  lobes,  accompanied  by  definite  saddles 

at  the  umbilical  depressions. 

The  last  two  stages  are  progressive  modifications  confined  to  the  larvae  of 
Ammonoids,  and  are  not  present  in  the  ephebic  stages  of  any  known  species. 
The  asellate  condition  of  the  first  septum  is  found  in  the  ananepionic  stage  of 
one  species  of  the  Clymeniidae,  according  to  Branco,  but  his  figure  shows  a 
saddle  on  the  venter.  The  Nautilinidae  and  Gephyroceratidae  are  asellate,  and 
the  Glyphioceratidae  also  in  some  primitive  Devonian  genera,  but  latisellate  in 
others,  and  angustisellate  in  the  Trias.  The  Triassic  Lobitidae  and  Arcestidae 
are  latisellate,  while  the  Cladiscitidae  and  the  Phylloceratidae  are  angustisellate 
^  ji  c  throughout.       The 

embryosof  theCera- 
tidae  are  very  little 
known,  but  are  sup- 
posed  to  be  latisel- 
late, while  the 
highly  specialised 
Pinacoceratidae  are 
angustisellate.  The 
remaining  system- 
atic  groups  are 
wholly  Jurassic  and 
Cretaceous,  and  so 
far  as  known,  the 
first  septa  are  an- 
gustisellate. 

Sutures} — The  second  septum  (Fig.  1141)  in  all  but  the  most  primitive 
forms  becomes  divided  by  an  entire  azygous  lobe  on  the  venter,  often  termed 
the  "  siphonal  lobe,"  but  herein after  feferred  to  as  the  ventral  lohe,  and  by  a 

^  The  terminology  comnionly  in  vogue  designates  the  sutural  inflectioiis  as  follows  : — The  ventral 
or  external  lobe  is  bounded  on  eitlier  side  of  the  mesal  plane  by  the  \a.vge  ßrst  or  mpeincn'-lateral 
saddle.  This  is  followed  by  the  first  or  superior-lateral  lobe,  and  then  come  the  second  or  inferior- 
lateral  saddle  and  lobe  in  tlie  order  nanied.  All  additional  inflections  occurring  ])etween  the  second 
lateral  lobe  and  the  line  of  Involution  are  termed  auxüiaries,  and  are  nntnbered  in  replar  order. 
The  antisiplional  is  also  known  as  the  internal,  dorsal  or  coiiwiellar  lobe.  By  "lobes"  are  always 
nnderstood  the  angulated  or  digitated  portions  of  the  snture  which  are  directed  backicards,  away 
froni  the  niouth  of  the  shell ;  "  saddles  "  are  the  elevations  between  them,  which  point  tmcards  the 
aperture  of  the  shell. 


^^WxATN 


A,  Development  of  sntures  in  a  latisellate  Qoniatite,  Gastrioceroft  dioxlrma 
(Goldf.).  Lower  Carboniferous ;  Choquier,  Belgiiini.  B,  Same  in  a  latisellate 
Ammonite  {Tropites  suhhuUatiis  Hauer).  G,  Same  in  an  angustisellate  Ammonite 
(all  after  Branco).  Sutures  of  the  first  volution  are  lettered  consecutively  from 
<i  toi;  those  of  the  second  from  m  to  s. 


620 


MOLLUSCA 


PHYLÜM  VI 


smaller  azygous  lobe  (shown  to  the  left  in  Fig.  1141,  A-C)  on  the  dorsum, 
usually  termed   the 


LSm 


Suture  -  line  of  Cyrto 
clymenkt  laevigata  Münst 
Devonian. 


Suture-line  of  Anarcestes  subnautülnus 
(Schloth.)-     Devonian. 


L       EL 

Fig.  1144. 

Suture-line  of  Aganides  sulcatus 
(Münst.).     Devonian. 


oZ2  aZl 


Left  half  of  suture-line  of  Ceratites  nodosus 
de  Haan.     Trias. 


f/.  This  imdivided  ventral  lobe  (Figs.  1143, 
1144,  EL)  persists 
throughout  the  Nau- 
tilinidae  so  far  as 
knovvn,  and  is  obliter- 
ated  by  a  secondary 
ventral  saddle  only 
in  the  Clymeniidae. 
It  is  present  throughout  the  ontogeny  of  the  simplest  or  radical  forms  of 
Glyphioceratidae,  Beloceratinae  and  Arcestidae.  But  in  the  Devonian  Gephyro- 
ceratidae  and 
in  the  Triassic 
Ceratidae,  shells 
having  imdivided 
ventral  lobes  have 
notbeenrecorded; 
in  the  Tirolitinae 
but      one      such 

species  has  been  doubtfully  described.     This  class  of  radicals  is  replaced  in 
these  groups  by  those  having  the  ventral  lobe  divided  by   a   small  saddle 

usually  called  the  ventral  or 
siphonal  saddle  (Fig.  1146,  m). 
The  class  of  radicals  having 
entire  ventral  lobes  disappears 
before  the  close  of  the  Trias. 

The  entire  antisiphonal  lobe 
has  a  more  extensive  distribution 
than  the  entire  ventral  lobe,  being 
present  throughout  the  ontogeny 
of  Nautilinidae,  Clymeniidae  and, 

Siphonal  saddle;  n,  Line  of  inrolution.     EL,  Ventral  (also  p  „„ViTTT^/^«QT.r,f  I^^orv  IV/Tz-wcf    r^f    fVio 

called  siphonal  or  external)  lobe,  traversed  by  the  siphuncle.  Vrepnyroceratmae.         IViOSL    Ol    tne 

L  First  or  superior-laterallobe ;?,  Second  or  i^  Glyphioceratidae    have    this     lobe 
lobe.     ES,  LS^,  LS^,  First  second,  and  third  lateral  saddles.  .         ,  .     ,  i  •r>  t    • 

IS,  Dorsal  saddle.    IL,   Antisiphonal  lobe,    i,   First  dorsal  entire,  but  it  beCOmeS  bind  ID  ths 

lobe  lying  on  line  of  Involution.  i    ,  ,  j.  •    ^'       i    £ 

later  stages  oi  specialised  lorms. 
The  radicals  of  Beloceratinae  have  it  entire,  but  in  specialised  genera  it  becomes 
bifid  or  even  trifid.  It  is  known  to  be  entire  in  only  a  few  of  the  Lecanitinae, 
and  is  bifid  in  most  of  the  Ceratitidae  and  Arcestidae,  besides  having  for  the 
most  part  entire  sides.  It  is  also  entire  in  some  phylogerontic  species  of  the 
Trias.  In  the  Desmoceratidae  and  Ly  toceratidae  it  is  generally  bifid,  but  may 
be  trifid  or  irregulär  in  some  species,  and  is  accompanied  by  an  extraordinary 
growth  of  two  of  the  branches  inwards  in  a  large  number  of  forms.  In 
Jurassic  and  Cretaceous  Ammonoids,  it  is  as  a  rule  more  or  less  complicated 
by  the  development  of  secondary  inflections  on  the  sides,  termed  marginals. 

Paired  or  zygous  lobes  and  saddles  (Fig.  1141)  appear  between  the  two 
azygous  lobes  and  belong  to  two  series,  the  laterals  or  externals,  and  the 
dorsals.  The  first  broad  external  lateral  inflections,  called  the  "  first  pair  of 
lateral  saddles,"  are  formed  by  the  ventral  lobe  and  the  corresponding  first 
pair  of  dorsals  by  the  formation  of  the  antisiphonal  lobe ;  and  between  these 
there  appears  a  broad  lobe,   either  wholly  or   the   most  part  external  (Fig. 


FiCx.  1146. 
Kight  suture-line  of  Coroniceras  bisulcatum  Brug.    Lius. 


CLASS  V 


CEPHALOPODA 


621 


1141,  J).  This  is  the  stage  marked  by  four  lobes  and  saddles — two  azygous 
and  two  zygous  lobes,  and  four  zygous  saddles.  The  wide  lateral  lobes  in  the 
next  stage  (Fig.  1141,  Ck)  are  divided  by  saddles  that  arise  on  or  near  the  lines 
of  Involution.  These  divide  the  two  lobes  into  four,  one  pair  being  in  part  or 
wholly  dorsal,  and  becoming  eventually  the  first  pair  of  dorsal  lobes  ;  the 
others  develop  into  the  "first  pair  of  lateral  lobes."  There  are  accordingly 
six  lobes  and  six  saddles  at  this  stage.  In  the  next  stage  (Fig.  1141,  A,  Bm, 
Gm)  the  saddles  bridging  the  lines  of  involution  become  divided  by  lobes 
arising  on  or  near  the  lines  of  involution,  and  the  inner  arms  of  the  saddle  so 
formed  thus  become  the  second  dorsal  saddle,  while  the  outer  form  the  second 
lateral  saddles ;  but  in  some  forms  they  may  both  pass  into  the  lateral  series. 
This  stage,  therefore,  has  eight  lobes  and  eight  saddles — three  paired  lobes 
and  four  saddles  on  either  side  of  the  mesal  plane,  and  two  azygous  lobes. 

Additional  inflections  arise  in  like  manner  along  or  near  the  line  of 
involution  during  succeeding  stages.  But  there  is  considerable  irregularity  in 
their  advent  even  in  the  eight-lobed  stage,  and  still  more  so  at  later  periods ; 
hence  the  above  description  must  be  regarded  as  a  very  general  one,  although 
serving  to  indicate  a  few  primitive  lobes  and  saddles  that  are  generated  during 
the  younger  stages,  and  are  usually  recognisable  in  the  adult. 

In  subsequent  stages  additional  inflections  arising  on  or  near  the  lines  of 
involution  pass  outward  as  the  sides  of  the  shell  broaden  by  growth ;  and  the 


Fio.  1147, 


Pinacoceras  tnctternwhi  (Hauer).  Keuper ;  Someraukogel,  near  Hallstadt,  Äustria.  Left  suture-line,  much 
reduced,  showing  auxiliary  (inner)  and  adventitious  (oiiter)  inflections.  The  three  longest  lobes  in  the  niiddle 
are  the  flrst,  second,  and  third  laterals  (after  Hauer). 

same  law  holds  true  for  the  dorsum,  but  of  course  here  the  inflections  pass 
inward  toward  the  mesal  plane.  The  number  of  inflections  on  the  dorsum  is 
more  limited  in  all  forms  than  the  laterals,  and  they  have  simpler  outlines. 
The  inflections  added  to  the  sides  after  the  first  two  or  three  saddles  and  lobes 
appear  are  usually  called  the  aiixiliaries  (Figs.  1145,  al;  1147),  but  the  current 
use  of  this  term  is  not  consistent  with  the  development  of  the  inflections,  and 
the  distinctions  are  based  for  the  most  part  on  the  contrast  in  size  between 
the  saddles  and  lobes  as  they  appear  in  the  adult  of  different  types.  When 
the  ontogeny  is  known,  however,  the  auxiliary  inflections  can  be  properly 
discriminated  and  described,  but  otherwise  are  liable  to  confuse  the  nomen- 
clature.  Adventitious  inflections  (Fig.  1147)  arise  between  the  first  pair 
of  laterals  and  the  median  line  of  the  venter,  either  by  the  growth  of 
marginals  in  the  arms  of  the  ventral  lobe,  or  by  division  of  the  outer  parts  of 
the  first  lateral  saddles,   or  by  division  of  the  inner  parts  of  the  siphonal 

saddle. 

The  reo-ions  of  greatest  metabolism  or  growth-changes  in  each  genetic 
series  are  near  the  lines  of  involution,  and  it  is  here  that  new  inflections  are 
usually  formed.     The  later  formed  lobes  and  saddles  in  these  regions  repeat 


622  MOLLUSCA  phylüm  vi 

in  their  own  development  the  ontogenetic  stages  of  modification  through 
which  the  older  ones  have  already  passed.  It  follows  also  from  this  that  the 
lobes  and  saddles  nearest  the  umbilical  lines  of  In- 
volution are  simple  and  often  entire,  and  are  parts 
of  a  series  that  become  progressively  more  compli- 
cated  outwards  to  the  lines  or  columns  of  the  oldest 
class — the  first  lateral  lobes  and  saddles.  When 
there  are  adventitious  lobes,  this  series  is  reversed 
on  the  ventral  side  of  the  first  pair  of  saddles.  The 
inversion  is  sometimes  quite  complete,  as  in  some  of 
the  Beloceratinae,  thus  indicating  unusual  metabolism 
on  the  venter  like  that  of  the  regions  of  Involution. 
Jackson's  law  of  the  localised  recapitulation  of  onto- 
MMffiSfwiuSiLS^'TSl  genetic  stages  is  well  exemplified  by  the  history  of 
FeXarfoS;  V^AntSlphonai  sutures  amoug  Ammonoids  as  already  shown  by  him 

lobe  ;    L,   Superior'  lateral   lobe  ;    in  Placeuticeras. 

l,  Inferior  lateral  lobe;    ES,  Ex-  ™,  ,  .1.     i       r    j      •  j.-  j.i       i    i  i 

ternai  saddie ;  LS,  Is,  First  and  i  he  above  method  of  desiguatiug  the  lobes  and 

second  lateral  saddles.  saddles  as  paired  in  the  external  aspect  and  on  the 

dorsum  on  either  side  of  the  mesal  plane  disregards,  for  sake  of  convenience, 
an  important  fact  that  should  be  noted ;  namely,  that  the  azygoüs  ventral  and 
dorsal  lobes  are  in  reality  paired  with  each  other  in  the  mesal  plane ;  also 
that  the  primitive  dorsals  and  external  lateral  inflections  correspond  in  the 
same  sense  to  one  another,  and  are  also  more  or  less  united  across  the  septa 
in  some  forms. 

The  outlines  of  the  paired  lobes  and  saddles  first  become  complicated  in 
the  Carboniferous  Glyphioceratidae.  "Minor  or  marginal  inflections  are  intro- 
duced,  and  what  are  termed  bifid  or  trifid  lobes  occur  in  the  arms  of  the  ventral 
lobe  (Fig.  1182) ;  they  then  affect  the  primitive  first  lateral  lobes  and  saddles, 
and  extend  thence  toward  the  line  of  Involution  (Fig.  1187).  These  marginal 
inflections  increase  greatly  in  niimber  and  complexity  during  the  Permian, 
become  preponderant  in  the  Trias,  and  universal  in  the  Jura  and  Cretaceous. 
Duiing  the  Carboniferous  it  is  the  lobes  only,  as  a  rule,  that  are  thus  modified; 
but  in  the  Permian  the  saddles  too  are  often  aff'ected.  *  The  modifications 
in  outline  proceed  from  the  lobes  to  their  sides,  and  thence  to  the  saddie  bases, 
except  in  certain  cases  when  direct  division  of  the  saddles  takes  place  by  the 
outgrowth  of  secondary  median  lobes  that  divide  their  bases.  All  these 
secondary  lobes  and  saddles  are  termed  marginals. 

Siphuncle. — The  caecal  condition  of  the  siphuncle  is  apparently  confined  to 
the  ananepionic  stage  or  first  septum,  but  J.  P.  Smith  has  shown  that  some 
species  of  Lytoceras  and  Phylloceras  have  a  bulbous  enlargement  of  this  organ, 
which  may  persist  in  several  nepionic  camerae.  This  is  apparently  a  persistent 
remnant  of  the  caecal  enlargement.  The  siphuncle  of  all  Ammonoids  is  larger 
in  Proportion  to  the  volution,  and  apt  to  be  nearer  the  centre  (Figs.  1149,  1150) 
during  the  young  than  at  later  stages,  and  is  also  retrosiphonate,  as  in  Nauti- 
loids.  It  remains  retrosiphonate  in  the  Clymeniidae,  Nautilinidae,  and  most 
Gephyroceratidae,as  well  as  primitive  forms  of  Glyphioceratidae;  but  it  becomes 
transitional  (having  both  funnels  and  fofwardly  directed  collars)  in  more 
specialised  Carboniferous  Glyphioceratidae,  and  finally  prosiphonate  (funnels 
lost  collars  alone  remaining)  in  Permian  genera.  Most  Triassic  and  all  Jurassic 
and  Cretaceous  genera  have  the  siphuncle  chloiochoanitic.     The  above  stages 


I 


CLASS  V 


CEPHALOPODA 


623 


are  repeated  in  regulär  succession  during  the  ontogeny  of  chloiochoanitic  forms 
(Fig.    1149)  except  when  accelerated  development   (tachygenesis)  occurs,  and 


Fio.  1149. 

Tropites  cf.  phoebus  Dittm.  Trias.  Bn- 
larged  section  in  the  median  plane  of  the 
young,  showing  retro.siphonate  funnels  in 
the  nepionic  stage,  then  transitional,  and 
later  prosiphonate  funnels.  a,  Position  of 
protoconch  (after  Branco). 


Amaltheus  spinatus  Brug.  Lias. 
Section  parallel  to  median  plane,  show- 
ing Position  of  the  siphuncle.  a,  Pro- 
toconch ;  c,  Caeciim  (after  Branco). 


then  the  monochoanitic  stage  may  disappear.  The  reduction  in  size  of  the 
siphuncle  among  Ammonoids  is  obviously  correlated  with  loss  of  functional 
importance,  as  is  also  the  case  among  more  specialised  Nautiloids ;  and  con- 
sequently  organic  deposits  are  not  found  in  the  caraerae  of  these  shells. 

Living  Chamber. — This  varies  greatly  in 
all  of  its  dimensions,  thus  indicating  difFer- 
ences  in  the  size  and  proportions  of  the 
animal,  since  its  body  parts  were  probably 
wholly  contained  within  this  cavity.  The 
lines  of  growth  and  the  few  apertures  known 
among  Nautilinidae  and  Clymeniidae  show 
that  they  had  hyponomic  sinuses  on  the 
venter,  and  were  swimmers  like  Nautiloids. 
The  same  was  probably  true  of  the  Gephyro- 
ceratidae,  except  during  the  gerontic  stage  of 
some  species  when  a  ventral  crest  arises,  as  Fig.  1151. 

demonstrated    by    Clarke.        In    the    Glyphio-        ParUnsonia  parkinsoni  (Sowerhy).    Middle 

ceratidae  and  Beloceratidae  many  species  that  wShuib^lTenirrglTenUcrprlsip^^^ 
retain    the   so-called    goniatitic    form    have  «ndposition  of  protoconch  (a)  ^^^^^ 
hyponomic    sinuses,    but    occasionally    short 

ventral  crests  appear,  and  later  these  become  general.  Only  radical 
Paleozoic  forms  of  the-Arcestidae  have  retained  the  hyponomic  sinus ;  short 
obtuse  crests  appear  in  the  Trias,  and  continue  thereafter.  Jurassic  and 
Cretaceous  Ammonoids  have  as  a  rule  more  pointed  rostra  than  those  of  the 
Trias,  and  frequently  develop  lateral  crests  and  lappets  (Figs.  1152,  1156). 

Very  decided  decrease  in  the  dimensions  of  the  living  chamber  during  the 
senile  stage  does  not  occur  as  a  rule  among  Paleozoic  forms ;  but  this  con- 
dition  appears  among  the  Triassic  Haloi'itinae  and  Tropitidae  with  a  corre- 
sponding  contraction  of  the  aperture.  The  Arcestidae  (Fig.  1222)  and  some 
species  of  the  Ceratitidae  also  often  have  very  narrow  openings  during  the 


624 


MOLLUSCA 


PHYLUM  VI 


paragerontic  substage,  biit  the  condition  is  in  no  sense  phylogerontic  except 

LoUtes,  and  the  like  (Figs.  1217,  1218). 

Pompeckj,  in  an  important  essay,  asserts  that  contracted  living  Chambers 
are  invariably  developed  in  old  age,  and  that 
small  Shells  possessing  them  are  consequently  not 
immature  individuals,  but  dwarfs  (Fig.  1156). 
It  is  probable  that  large  numbers  of  shells  are 
indeed  dwarfs,  but  it  is  also  a  fact  that  contrac- 
tion  of  the  living  Chamber  and  volutions  occurs 
in  some  forms  during  comparatively  early  stages ; 
and  sometimes  in  such  a  way  as  to  affect  the 
ephebic  stages  of  the  ontogeny,  when  the  forms 
become  truly  phylogerontic.  This  latter  term  is 
used  to  designate  shells  in  which  the  ontogeny 
has  become  permanently  modified  by  the  assump- 
tion  of  retrogressive  characters  that  were  intro- 
duced  first  in  the  senile  stages  of  allied  pro- 
gressive species.  Whether  these  peculiar  forms 
SchioenbacUa  cristata  (Deiuc).   have  contracted  apertures  in  their  earlier  stages, 

äXum.  ^P""*"""  ""^"^  '''''^'■^'   and  then  resorb  them  before  building  further,  or 

whether  they  never  add   lateral    lappets,    rostra, 

etc.,  as  claimed  by  Pompeckj,  until  the  last  resting  stage  of  the  ontogeny 

(Fig.  1156),  it  is  obvious  that  they  are  permanently  affected  by  phylogerontic 


Fig.  1152. 


Fig.  1153. 

Sphaeroceras  hrong- 
niarti  (Sowb.).  Oolite. 
Aperture  with  broad, 
contracted  ventral  ros- 
trum. 


1154. 


Normannites  braiken- 
rulfji  (Sowb.).  Oolite. 
Aperture  with  lateral 
lappets. 


Fig.  1155. 

Oppelia      nimbaia 
(Oppel).  Jura. 

Lateral  lappets. 


Fig.  1156. 

Oecoptychius  re- 
fractus  (de  Haan). 
Jura.  Living  Chamber 
contracted,  with  ros- 
trum  and  lappets. 


characters.  These  forms  are  comparatively  rare  in  the  Trias  {LoUtes, 
Cochloceras),  but  their  number  is  sensibly  increased  in  the  Jura,  although 
usually  confined  to  special  localities.  During  the  Cretaceous  they  become 
more  numerous  and  more  widely  distributed  (Figs.  1261,  1262).  In  their 
extreme  modifications  they  become  more  or  less  uncoiled  and  finally  per- 
fectly  straight. 

Crick  and  Waagen  maintain  that  Ammonoids  had  an  annular  band  as  well 
as  shell  muscles,  and  that  these  served  both  to  hold  the  anirnal  in  the  living 
Chamber,  and  also  formed  an  air-tight  band  around  the  face  of  the  mantle, 
fastening  the  latter  to  the  shell  (Fig.  1157).  Such  was,  however,  probably 
not  the  only  means  of  attaching  the  animal  to  the  shell.  The  steady  pro- 
gressive complication  of  sutures,  affecting  both  lobes  and  saddles  as  well  as 


CL.VSS  V 


CEPHALOPODA 


625 


Fio.  1157. 

Oppelia  steraspis  (Oppel). 
Upper  Jura ;  Solenhofen.  Com- 
pressed  shell  with  aptychus  (a) 
preserved  in  living  Chamber  and 
distinct  impression  of  sliell 
rauscles  (h)  (after  Waagen). 


their  marginal  inflections,  is  directly  correlated  with  the  outgrowth  of  rostra. 

The   presence  of   a  rostrum  indicates   the  disuse   and   disappearance  of   the 

swimming  organ  {hyponome),  which  in  Nautilus  causes 

the  formation  of  the  hyponomic  sinus  in  the  aperture, 

and  flexed  growth-lines  on  the  venter.     These  facts 

and  the  gregarious  littoral  habits  of  Ammonoids  show 

that  they  probably  crawled   along  the   bottom  with 

their  shells  carried  above  them,  very  rarely  swimming. 

Their  shells  are  also  less  bulky  in    proportion  than 

those  of  Nautiloids,  and  correspondingly  less  buoyant. 

All  these  observations  justify  the  hypothesis  that  the 

progressive  complication  of  Ammonoid   sutures  took 

place  because  of  their  Utility  in  helping  to  carry  and 

balance  the  shell  above  the  extruded  parts  when  the 

animal  was   crawling.      The  greater  complication  of 

the    marginals    in    Jurassic    Ammonoids,    where    the 

number  of  auxiliary  lobes  and  saddles  is  often  reduced 

(Fig.    1253),  and  the  multiplication  of  the  principal 

inflections  in  Fseudoceratites  of  the  Cretaceous  in  com- 

pensation  for  the  suppression  of  marginals  (Fig.  1309),  are  all  accounted  for 

by  this  theory.     The  phylogerontic  forms,  in  which  the  lobes  and  saddles  are 

sometimes  reduced  in  number,  and  the 
marginals  are  also  less  complex — together 
with  the  Position,  form  and  mode  of  growth 
of  the  last  volution,  and  the  short  rostra 
— suggest  that  these  creatures  could  not 
have  been  active  crawlers  during  the 
greater  part  of  their  ontogeny. 

The  occurrence  of  broods  of  young 
Shells  in  the  living  Chamber  may  be  taken 
as  suggesting  that  some  Ammonoids  were 
viviparous,  but  the  examples  of  this  are 
too  rare  to  be  relied  upon  for  making  a 
general  Statement. 

Opercula. — Plates  have  been  found  in 
situ  closing  the  aperture  and  correspond- 
ing  in  position  to  the  hood  of  Nautilus  in 
a  number  of  Ammonoid  shells  (Fig.  1158). 
This  positive  fact,  and  the  obvious  fitness 
of  such  plates  to  serve  as  opercula,  lead 
to  the  inference  that  they  were  for  med  by 
an  organ  similar  to  the  hood  of  Nautilus, 
and  protected  the  animal  when  it  was  re- 

tracted  into  the  living  chamber.     When  composed  of  a  single  piece,  the  plate 

is  called  an  anaptychus ;  in  such  cases  it  is  invariably  carbonaceous,  and  was 

doubtless  horny  in  the  living  animal  (Fig.  1160).     The  anaptychus  is  rare  in 

the  Paleozoic,  and  has  not  yet  been  found  in  the  Trias,  but  occurs  among  the 

Arietidae  and  Amaltheidae  of  the  Lower  Jura.     The  operculum,  when  formed 

of  two  plates,  is  termed  an  aptychus,  and  is  always  of  calcareous  composition. 

It  is  noteworthy  that  these  plates  occur  uniformly  in  the  same  position  among 
VOL.  I  2  s 


1158. 


Oppelia  subradiata 
(Sowb.).  Inferior 
Oolite;  Dundry. 
Aptychus  in  place, 
closing  aperture 
(after  Owen). 


Aptychus  Ja  mcllonns 
preserved  as  in  Fig.  1157. 
Upper  Jura;  Solen- 
hofen, Bavaria. 


626 


MOLLUSCA 


PHYLÜM  VI 


some  species  from  certain  localities,  inside  the  living  Chamber  and  close  to  the 
^  j^         venter    (Figs.    1159,    1161),    a    circumstance    that    led 

Waagen  to  suppose  they  served  to  protect  the  nida- 
mental  gland  of  female  shells.  As  shown  by  Michael 
in  Oppelia,  even  the  embryonic  shells  were  furnished 
with  aptychi.^ 

Aptychi  are  composed  of  three  layers,  of  which  the 

middle  one  is  the  thickest  and  exhibits  a  cellular  struc- 

ture,  whereas  the  two  outer  layers   are  comparatively 

(Fig.     1164).      Detached    aptychi     have    been 


Fig.  1160. 


Anaptychi.    A,  Amaltheus    Clense 
nnatus    Brug. 
B,  Goniatites  uchtensis  Keys 


.spiruttus  Bvng.ua.8.yy   classificd    by  Zittel    into    several  groups    according    to 


their  structure.  Cellulosi  (Fig.  1163)  are  smooth,  thick 
plates,  with  punctate  external  surface ;  Imhricati  (Fig.  1159)  have  ^  the 
surface  traversed 
by  oblique  folds 
or  costae;  Pundati 
(Fig.  1164,  C) 
have  rows  of 
punctae  and  over- 
lapping  folds; 
Granulosi  include 
thin  plates  having 
the  external  sur- 
face covered  with 
concentric  folds  or 
rows  of  tubercles 
or  spinules ;  Bugosi 
are  thick  plates 
with  irregularly 
arranged  granules 
or  rows  of  nodes  on  the  outer  surface 


Fig.  1161. 

Harpoceras  lythense  (Sowb.).  Upper  Lias  ; 
Boll,  Würtemberg.  Aptychus  in  the  living 
Chamber. 


Fig.  1162. 


Scaphites  spiniger  Schlüter. 
Upper  Cretaceous  ;  Coesfeld, 
Westphalia.  Detached 

aptychus. 


and  Cretaceous. 


Nigrescentes  (Fig.  1161)  are  covered 
with  a  thin  carbonaceous  coat- 
ing;  and  Coalescentes  (Fig.  1162) 
have  the  two  thin  plates  fused 
along  a  median  depression.  This 
last  is  a  phylogerontic  condition 
of  the  aptychus  occurring  in 
Scaphites. 

Classification. — Leopold  von 
Buch  prepared  the  way  for  a 
general  Classification  of  the 
Ammonoidea  by  pointing  out 
three  grand  divisions  which  he 
called  "genera."  These  were 
the  Paleozoic  Goniatites,  Ceratites, 
from  the  Trias  and  Cretaceous, 
and  Ammonites,  from  the  Jura 
Von  Buch's  chief  distinctions  were  based  on  the  outlines  of 


Fi(i.  1163. 

Aptychus  laevis  v.  Meyer.     Litliographic  Stone  ;  Solenhofeii 
Bavaria.     A,  External  aspect;  B,  Internal,  i/i. 


1  Michael,  R.,  Zeitschr.  deutsch,  geol.  Ges.,  1894,  vol.  x\\\.—Retowski,  0.. 
1891,  vol.  ii. — Blackmore,  IL  P.,  Geol.  Mag.,  1896,  dec.  4,  vol.  iii. 


Neues  Jahrb. 


Min.J 


CLA.SR  V 


CEPHALOPODA  G27 

the  lobes  and  saddles,  and  were  as  natural  and  well-founded  as  the  knowledge 


Fio,  1164. 

Vertical  sections  of  ai)tychi  belonging  to  A,  CellvXosi  {Ammonites  zonatus  Stopp.) ;  B,  Imhricati  (Ammonite's 
profundiis  Voltz);  and  C,  Punctati  {A.  imnctatus  Voltz).    3/j  (after  Meneghini  and  Bornemann). 

of  the  time  permitted.  D'Orbigny,  Quenstedt,  Sandberger  and  Barrande 
greatly  increased  our  knowledge  of  structure  and  Variation,  and  defined  a 
number  of  new  genera. 

The  next  marked  epoch  dates  from  the  publication  of  Mojsisovics's  great 
works  on  the  Trias,  which  made  known  a  fauna  as  rieh  and  complex  as  that 
of  the  Jura.  Suess,  Neumayr,  Branco,  Waagen,  Buckman,  Grossouvre,  Haug, 
Diener,  Douvillö,  Kilian,  Zittel,  Karpinsky,  Hyatt  and  others  made  advances 
of  essential  importance  along  difFerent  lines.  All  of  these  authors  attempted 
to  trace  phylogenetic  histories  which  of  necessity  crossed  the  lines  of  the 
older  classifications  at  right  angles,  and  sometimes  bridged  over  the  divisions 
of  geologic  time. 

Suborder  A.     INTRASIPHONATA  Zittel. 

Family  1.     Olymeniidae  Gümbel, 

Conchs  varying  from  forms  like  Anarcestes  to  those  that  are  more  or  less  compressed  in 
section,  and  from  completely  discoidal  to  compressed  and  highly  involute  shells,  the  surface 
heing  either  smooth  or  ivith  large  spines.  The  characteristic  ventral  saddles  are  almost 
imperceptible  in  some  primitive  species,  and  although  entire  and  large  as  a  rule,  are 
in  some  genera  divided  by  entire  ventral  lobes.  Septa  concave  along  the  mesal  plane. 
Siphuncle  dorsally  situated.  Living  Chamber  occupying  about  three-fourths  of  a  volution  ; 
aperture  with  hyponomic  sinus. 

The  ventral  saddles  are  developed  by  the  obliteration  of  primitive  ventral  lobes 
and  fusion  of  the  first  pair  of  saddles  (Branco).  It  is  at  present  questionable  whether 
the  ventral  lobes  of  some  genera  are  secondary  modifications  or  retentions  of  the 
primitive  ventrals,  and  also  whether  these  can  be  regarded  as  divided  ventrals  even  in 
Gymaclymenia.  The  antisiphonal  lobe  is  large  and  long,  and  often  fused  with  the 
siphuncular  funnels.  The  dorsal  sutures,  so  far  as  known,  are  very  peculiar,  having 
only  a  pair  of  large  saddles  confluent  with  the  last  pair  of  external  saddles ;  or  one 
pair  of  zygous  saddles,  and  one  pair  of  zygous  lobes,  the  second  pair  of  zygous  saddles 
being  confluent  with  the  innermost  external  pair. 

The  Perforation  tliroiigh  the  umbilicus,  so  constant  in  Nautiloids,  is  abeent,  and  so 
too  are  the  umbilical  depressions  on  either  side  of  the  neck  of  the  protoconch,  common 
in  other  Ammonoids.  The  forms  are  nevertheless  ammoniticones,  having  the  proto- 
conch and  other  characters  of  the  order.  The  first  septum  is  described  as  asellate 
(Branco),  but  is  tigured  as  having  a  broad  saddle  on  the  venter. 

Primitive  forms  similar  to  Anarcestes,  but  dift'ering  in  that  tlie  sutures  have  broad 
entire  ventral  saddles  and  broad  rounded  lobes ;  or  if  the  latter  are  angulated,  they 


628 


MOLLUSCA 


PHYLUM  VI 


are  incoraplete  internally,  rising  to  saddles  at  the  lines  of  Involution.     Siphuncle 
tubulär  and  small,  and  funnels  comparatively  sliort  (Gümbel). 

1.   Gyrtoclymenia  (Fig.  1165),  Oxyclymenia  (Fig.  1167)  Gümbel;  Platyclymenia 

Hyatt.     Devonian. 

Fio.  1166. 


§2. 


Conchs  similar  to  tliose 
of  preceding  genera,  but  sutures 
liave  two  pairs  of  lateral  saddles, 
and  tliere  is  a  ventral  lobe  witli 
'  a  median  saddle. 

Cymuclymenia  (Fig.  1166),  Sellaclymenia  Gümbel.     Devonian. 
§  3.  Conchs  difFer  from  preceding  genera  in  that  the  sutures  have  deep  undivided 


Fig.  1165. 

Suture-line  of  Gyrtocly- 
menia laevigata  (Münst.). 


Butnre-line  of  Cymadymenüi 
striata  (Münst.). 


Fig.  1167. 

Oxyclymenia  undulata  (Münster). 
Upper  Devonian;  Elbersreuth, 
Fichtelgebirge. 


Fig.  1168. 

Gonioclymenia  speciosa  (Münst).     Upper  Devonian 
Schübelhammer,  Fichtelgebirge,     i/o. 


ventral  lobes,  and  sometimes  two  pairs  of  lateral  saddles  are  present.     These  last  may 
be  either  in  part  or  wholly  divided  by  marginals. 

Gonioclymenia  (Fig.  1168),  Gycloclymenia,  Discoclymenia  Gümbel;  Gryptoclymenia 
Hyatt ;  Äcanthoclymenia  Hyatt.    Type  Ä.  (Glymenia)  neapolitana  (Clarke).    Devonian. 

Suborder  B.     EXTRASIPHONATA  Zittel. 

The  Extrasiphonata  include  straight,  open-coiled  and  close-coiled  forms,  embracing 
the  old  groups  of  Goniatites,  Ammonites  and  Geratites,  between  which  there  are  no 
sharp  lines. 

The  Goniatites  are  the  oldest  and  most  primitive  Ammonoids,  chiefly  confined  to 
the  Devonian  and  Carboniferous.  They  are  mostly  small  in  size,  distinguished  from 
the  Clymeniidae  by  their  external  siphuncle,  and  from  the  rest  of  the  Ammonoidea  by 
their  simple  septa.  The  older  Goniatites  are  retrosiphonate,  and  the  aperture  usually 
has  a  ventral  sinus.  They  grade  over  into  Ceratites  and  Ammonites,  the  septa 
becoming  serrated  or  digitate,  usually  with  an  increase  in  the  number  of  lobes,  and 
with  the  development  of  the  forward-pointing  siphonal  coUars. 

Family  1.     Bactritidae  Hyatt. 

Bactriticonesi  and  cyrtoceracones,  usually  compressed  ellipitical  in  section,  and  c 
necting  through  Protohactrites  ivith  the  Nautiloidea. 


CLASS  V 


CEPHALOPODA 


629 


Bactrites   Sandb.   (Fig.    1169).       In   this,  the   only  genus,  the  shell   is  straight, 
gradually  tapermg,  and  round  or  compressed  elliptical  in  section.     Devonian. 


Family  2.     Nautilinidae  Hyatt  {NauUUni  Beyrich,  'pars). 


Mimoceracones  and 
ammoniticones,  rounded 
in  section.  Body- 
chamber  long.  Sutures 
have  narrow  saddles  on 
either  side  of  the  un- 
divided  ventral  lohe, 
and  hroad  lateral  lohes 
with  saddles  at  the  lines 
of  involution  or  on  the 
umbilical  zones,  tvhen 
the  latter  are  differen- 
tiated.  Antisiphonal 
lobe  absent.  Dorsiim 
with  a  hroad  azygous 
saddle.  Aperture  with 
a  deep  and  narrow 
hyponomic  sinus,  crests 
on  the  ventro  -  lateral 
angles,and  hroad  lateral 
sinuses  on  either  side. 

Mimoceras     Hyatt       „   .  •. 

,„.       ,  ,  _^s        >  Bactrites        eleyans 

{rig.  1170);  Anarcestes    Sandb.     Upper  De- 
Moi'?    ('Fi  CT«     1171     anrl     vonian ;    Büdesheim, 

Mojs.  (^rigs.   ii/i   ana    ^j^^j    .4,  Conch,  i/.- 
111^);  ProlobitesKdiV^.    b,    Suture- 


ß 


Fig.  1169. 


Fig.  1170. 
Mimoceras    comp^ressum    (Beyr.).      Lower    Devonian  : 
Wissenbach,  Nassau.      A,  B,  Natural  moulds,  Vi-      C 
^epionic  individual  enlarged.  ' 


Devonian. 


line, 
(after  Sandberger). 


Fig.  1171. 

Anarcestes  pleb^us  (Barr.).     Lower  Devonian  (^tage  G) ; 

Hlubocep,  Bohemia  (after  Barrande). 


Family  3.     Aphyllitidae  Frech. 

Ammoniticones  with  truncated  venters,  compressed  whorls  and  short  body -Chambers. 


Fig.  1172. 

Anarcestes    subnautilinu: 
(Schloth.).       Middle    Devonian 
Wissenbach,  Nassau. 


Fio.  1173. 

AgoniatUes  orcultus  (Barr.).    Lower  Devonian  (Etage  G) ; 
Hlubocep,  near  Prague,  Bohemia  (after  Barrande). 


Sutures  similar  to  those  of  the  Nautilinidae,  except  that  a  dorsal  azygous  lobe  is  sometimes 
present. 


630 


MOLLUSCA 


PHYLUM  VI 


Meek  (Äphißlites  Mojs.)  (Fig.  1173);  Palaeogoniatites  Hyatt.     Type 
P.  (Goniatites)  lituum  (Barrande).     Devonian. 

Paraphyllites  Hyatt.  Type  P.  {Goniatites)  tahuloides  (Barr.).  Dorsiim  of  this 
involute  form  is  entirely  occupied  by  a  large  azygous  lobe  terminating  in  a  minute 
annular  lobe  and  partial  cone  similar  to  that  observed  in  Nautiloids  and  in  Pinacites. 
The  inner  extension  or  cone  is  not  present  elsewhere  among  Ammonoids  so  far  as 
known.     Devonian. 

Pinacites  Mojs.  Highly  involute,  compressed  ammoniticones  with  acute  venters. 
Septa  biconcave,  owing  to  a  division  of  the  lateral  lobes  by  narrow  saddles  which 
are  connected  by  ridges  with  corresponding  saddles  on  the  dorsum.  There  are  also 
saddles  at  the  unibilical  angles  and  on  either  side  of  the  ventral 
lobes.  The  azygous  dorsal  lobe  is  large.  Dorsum  vi^ith  one  pair 
of  narrow  zygous  saddles  and  one  pair  of  broad  zygous  lobes, 
giving  a  formula  of  eight  lobes  and  eight  saddles.  European 
Devonian. 

Family  4.     Tornoceratidae  Gürich. 

Involute  forms,  luith  ventral  sinus,  simple  septa  lihe  those  of 
Fig.  1174,  ^^^  AphylUtidae,  and  relatively  short  hody-chamhers. 

Tornoceras  simpiex  (v.  Tomoceras  Hyatt  (Fig.  1174),  Maeneceras  Hyatt  (Fig.  1176). 

Buch).  Upper  Devonian;    t^  •  J  \      ö  /»  j  \      b  j 

Büdesheim,  Eifel.  Devonian.  , 


Family  5.     Cheiloceratidae  Frech. 
Ammoniticones  varying  from  discoidal  and  Änarcestes-like  to  highly  involute,  com- 


'a^wvv^' 


Fig.  1175. 

Suture-line  of  Sporadoceras 
münsteri  (v.  Buch). 


Fig.  1176. 

Suture-line  of  Maeneceras 
terebratus  (Sandb.). 


Fig.  1177. 

Suture  -  line  of  Aganides 
sulcatus  (Münster).  Upper 
Devonian ;  Fichtelgebirge. 


Fig.  1178. 

Aganides  rotatorius  (de  Koninck).     Lower  Carboniferous  ; 
Tournay,  Belgium. 


pressed  shells  with  narrow  venters.     Shells  smooth,  hut  with  frequent  labial  constrictions. 
Body  chamler  long.     Aperture  without  hyponomic  sinus. 

In  this  family  the  septa  are  concave  along  the  mesal  plane  as  in  Nantiloids, 
becoming  convex  only  internally  and  laterally,  following  the  broad  internal  saddles  in 
the  zone  of  Involution.     Lobes  and  saddles  entire.     Primitive  forms  may  have  only 


CEPHALOPODA 


631 


two  broad  saddles  on  either  side,  but  more  specialised  sliells  may  have  two  pairs  of 
principal  saddles  fornied  by  division  of  the  primitive  first  laterals.  There  is  a  corre- 
sponding  development  of  narrow  saddles  and  lobes  on  the  dorsum,  but  primitive  forma 
liave  only  two  broad  saddles  here  as  in  Änarcestes.  Antisiplional  lobe  narrow,  entire, 
pointed.  From  this  family  sprang  tbe  Glyphioceratidae  of  the  Carboniferous,  and 
through  them  came  the  Tropitidae  and  Arcestidae  of  the  Triassic. 

Gheiloceras  Frech  {Parodoceras  Hyatt);  Sporadoceras  (Fig.  1175);  Aganides  Montfort 
(Figs.  1177,  1178).     Devonian  and  Carboniferous. 


Family  6.     Gephyroceratidae  Hang. 

Evolute  to  involute  forms^  mostly  laterally  compressed,  with  short  body-chamhers^  deep 
ventral  hyponomic  sinus,  and  without  labial  constric-  a 

tions.  This  group  includes  forms  with  simple 
goniatitic  septa,  forms  with  ceratitic  septa,  and  forms 
with  exceedingly  complex  ammonitic  septa. 

The  external  sutures  in  primitive  forms  some- 
times  approximate  to  those  of  Änarcestes,  but  the 
dorsals  have  only  one  large  azygous  lobe,  the  saddle 
being  confluent  at  the  line  of  Involution  with  the 
second  external  pair.  In  more  involute  forms  the 
antisiphonal  lobe  is  large,  entire  and  pointed  ;  there 
is  one  pair  of  dorsal  saddles,  and  one  of  broad 
dorsal  lobes ;  the  second  pair  of  saddles,  when 
present,  is  confluent  with  the  second  pair  of  lateral 
saddles, 

Subfamily  A.     Primordialinae  Hyatt 
(Primordiales  Beyrich). 

Distinguished  from  Änarcestes  by  the  divided 
ventral  lobes,  large  siphonal  saddles,  and  especially 
the  first  lateral  saddles,  which  are  very  prominent 
on  the  sides.     Adventitious  lobes  and  saddles  are      />„^fc„.„.,.„.,,„/„™<,„..^,/R„„,  %  TTr^r^or 

Gephyroceras  intumescens(iiejT.).  Upper 

formed  by  division  of  the  first  lateral  saddles.  Septa  Devonian ;  Nassau.  A,  Conch,  i/i-  -B. 
in  the   young  are  concave  and  similar  to  those  of     "  ^^^'  '°^" 

Änarcestes,  but  in  later  stages  become  convex  along  the  mesal  plane  as  in  typical 
Ammonoids.  Siphuncle  small,  subventran,  without  calcareous  sheath  ;  funnels  retro- 
siphonate  and  short,  except  in  Manticoceras,  where  they  are  prosiphonate. 

Gephyroceras  (Figs.  1138,  1179),  ikTavifzcoceras  Hyatt;  iVo6e/oceras  Clarke ;  Timanites 
Mojs.  Devonian.  Nomismoceras  Hyatt.  Gonioloboceras  Hyatt.  Type  G.  (Goniatites) 
goniolobus  (Meek).  Carboniferous.  •  Koenenites  Wedekind.  Devonian.  (This  and 
related  genera  are  described  by  Wedekind  in  Sitzher.  Ges.  Naturf.  Freunde  Berlin,  1913). 

From  the  Gephyroceratidae  probably  sprang  the  Meekoceratidae  of  the  Permian 
and  the  Lower  Trias,  and  through  them  came  the  Ceratitidae. 


Fio.  1179. 


Subfamily  B.     Beloceratinae  Fi-ech. 

Form  compressed,  discoidal,  involute,  with  high  whorls  and  narrow  acute  venters. 
Lobes  and  saddles  lanceolate,  with  numerous  adventitious  and  auxiliary  lobes. 

Includes  the  genus  Beloceras  Hyatt  (Fig.  1 1 80),  of  the  Upper  Devonian.  From 
the  Beloceratinae  probably  came  the  Sageceratinae,  the  Hedenstroeminae,  and  the 
Carnitinae,  and  possibly  the  Pinacoceratidae.  Beloceras  was  probably  derived  from 
Timanites  with  Probeloceras  as  a  connecting  link. 


632 


MOLLUSCA 


I'HYLUM  VI 


Family  7.     Prolecanitidae  Hyatt. 


The  youny  Uve  «  long  undivided  ventral  lobe.  Pnm^t^ve  forms  are  compreesed, 
discoidJ,aJmore  epecialised  gmera  become  invoUte  and  as^ume  a  ^od^fied ^^rcesjean 
a^pect.  Saddles  aremtire  in  the  former,  but  thefirst  latcraU  become  very  large  and  are 
Jbdivided  by  simple  marginal  lohes.  Lateral  lobes  entrre  m  pr^m^t^ve  genera  and 
become  bijid  or  trifid  in  specialised  forms,  but  rarely  have  more  nnmerous  d^g^taUons. 
Antüiphonal  lobe  entire  or  pointed.  Siplmnele  withont  ealcareous  sheath ;  funnels  pro- 
siphonate  so  far  as  hnown. 


yVVW^\ 


•^vAllnjUR/UK 


Fig.  1180. 

Belocerus  muüüobatum  (Beyrich).     Upper 
Devoiiian ;  Adorf,  Westphalia. 


Fig.  1181. 
Proleeanites  lunulicosta  (Sandb.). 
Upper    Devonian  ;    Nassau    (after 
Sandberger). 


Subfaiiiily  A.     Prolecanitinäe  Frech. 

Shells  discoidal  or  evolute,  coiupressed  or  siibquadrate  in  section.  Primitive  forms 
with  undivided  ventral  lobes,  and  rounded  saddles  and  lobes  of  the  lecanitean  type. 
More  specialised  shells  have  entire  hastate  lobes  and  saddles,  and  similar  but  divided 
ventral  lobes.  Aperture  with  well-marked  hyponomic  sinus.  Shells  smooth  or 
Costated,  and  often  with  longitudinal  ridges. 

Phenacoceras  Frech  ;  Proleeanites  Mojs.  (Fig.  1181).      Devonian  to  Garl)oniferous. 


Subfamily  B.     Noritinae  Karpinsky. 

Similar  to  Prolecanitinäe,  but  the  ventral  lobe  instead  of  becoming  divided  in  the 
usual  way,  retains  the  larval  trifid  stage  throughout  life  in  primitive  species.  In 
specialised  forms  the  larval  siphonal  saddles  enlarge  in  the  neanic  stage,  thus  building 
up  a  Single  siphonal  saddle  with  a  comparatively  large  siphonal  lobe.  First  lateral 
lobes  may  be  bifid,  trifid  or  completely  serrated  in  specialised  shells,  and  the  second 
and  other  lateral  lobes  also  may  become  ceratitic.  The  saddles,  however,  retain  more 
or  less  of  their  primitive  outlines,  and  their  bases  are  entire.    Sutures  with  adventitious 


CLASS  V 


CEPHALOPODA 


633 


inflections.     Apertures  have  crests  at  the  veiitro-lateral  angles  ;  straight  or  with  faint 
sutures  at  the  venter. 

Pronorites  Mo^s.  (Figs.  1182,  1183);  Triainoceras  Hyatt  (Fig.  1185);  Farapronorites 


Fic.  1184. 

öepta  of  Gordlllerites  angulatus  Hyatt  aud  Smith. 
Lower  Trias  ;  Idaho. 


Fi(i.  HS 


l'ronorUet>cydolohus(P\nU.). 
Lower  Carbonlferous  ;  Grass- 
iugtoii,  York.shire  (after 
Phillips). 


Fig.  1188. 

Septa  of  l'ronorites  urkannasensL- 
Öinith.  LowerCarboiiiferous;  Arkansas. 
i/-'  (alter  J.  P.  Smith). 


Fig.  1185. 

Suture-line  of  Triainocaras 
tuherculoso-costatum  (Sandb. ).  Upper 
Devonian. 


^^IWI*^ 


Fk;.  118(5. 

Suture-line  of  Nuritea 
gomlola  Mojs.  Muschelkalk  ; 
Schreyer  Alp,  near  Hallstadt, 
Anstria. 


Gemm. ;  Cordülerites  lüyatt  und  Smith  (Fig.  1184);  (1)  Amb^tes^Y'da,gen  ;  iVoWies  Mojs. 
(Fig.  1186);  Daraelites  Genim.     Devonian  to  Trias. 


Subfamily  C.     Medlicottiinae  Karpinsky. 

Shells  compressed,  discoidal  and  involute,  with  sinooth  or  costated 
often  costated  or  tuberculated  and  channelled  venter. 
Ventral  lobe  entire  in  primitive  species,  and  trifid  or 
dividedas  amoiig  the  primitive Noritinae  inmorespecialised 
forms.  First  lateral  saddles  simple  but  divided  in  primi- 
tive genera,  and  acquire  in  Medlicottia  through  hyper- 
trophy  and  the  development  of  marginals  extraordinary 
serrated  outlines.     Aperture  as  in  the  Noritinae. 

Sicanites  Gemm.;  Promedlicottia  Karp.;  Propina- 
coceras  Gemm. ;  Episageceras  Noetling ;  Medlicottia 
Waagen  (Figs.  1187,  1188).      Permian  to  Lower  Trias. 


sides,  and 


Fig.  1187. 
Suture-line  of  Medlwottia  primas  Waagen.     Pernio- 
Carbonlferous  ;  Salt  liange,  India  (afler  Waagen). 


Medlicottia  trautsrholdi  Gemm. 
Pernio -Carbonlferous  ;  Sosio, 
Sicily  (after  Genimellaro). 


634 


MOLLUSCA 


PHYLUM  VI 


Family  8.     Pinaooceratidae  Mojsisovics. 

Forms  with  involute,  compressed,  high  whorls,  with  narrow  and  often  acute  venters. 
Body -Chamber  short.  Septa  goniatitic  to  ceratitic^  to  digitale^  hut  always  with  adventitious 
and  auxiliary  lobes  in  addition  to  the  regulär  series. 

The  group  is  probably  derived  from  the  Beloceratinae,  at  least  in  so  far  as  it  is 
a  Unit.  This  is  almost  certainly  true  of  the  Sageceratinae  and  the  Hedenstroeminae ; 
the  Carnitiiiae  are  probable  derivatives  of  the  Hedenstroeminae,  and  the  Pinaco- 
ceratinae  apparently  are  derivatives  from  the  Sageceratinae. 


Subfamily  A.     Hedenstroemiinae  Waagen. 

Principal  lobes  and  saddles  with   ceratitic  outlines,  but  adventitious  lobes  and 

___...._._,,.,— „^       saddles  have  Sageceras -like  outlines. 

HHHHH|^^^^^^^^^^^^^^^^H       Antisiphonal  lobe  very  long. 

^^^^^^^^^^^^^^^^^^^^^^^^H       Dorsal  more  complex  than 

1 1  RH^^HI^^^^^^^^^^^^^^^^H       in  preceding  families.    Aperture  with 

^    I     ^m    ^^^^r       ^^^^^^^^^H  Hedenstroemia    Waagen    {Glypites 

■    I     rW    jHf        ^^^^^^^H  ^^aagen)    (Fig.     1189);    Prodromites 

Tjm}         ^^    ^^aS^B  ^"^^*^     ^^^     Weller     (Fig.     1190); 

'f^m  Äspenites   H.  and   S. ;    Longohardites 

"^W  Mojs.     Carboniferous  to  Trias. 


Fig.  1189. 
Hedenstroemia  kossimUi  H.  and  S. 


Lower  Trias  ;  Idaho. 


Fig.  1190. 
Prodromites  gorbyi  Miller.     Lower  Carboni- 
ferous ;  Missouri.     1/2  (after  J.  P.  Smith). 


Subfamily  B.     Sageceratinae  Hyatt. 

Similar  to  the  last,  but  lateral  lobes  bifid,  and  saddles  acutely  spade-shaped. 
Adventitious  and  auxiliary  lobes  numerous.  Antisiphonal  lobe  bifid.  Aperture  has 
smuous  lateral  outlines  with  crests  at  the  ventro-lateral  ridges. 

Iseudosageceras  Diener  (Fig.  1191);  Sageceras  Mojs.  (Fig.  1192).  Permian  and 
i  rias. 


CLASS  V  CEPHALOPODA  635 

Subfamily  C.     Carnitinae  Arthaber. 

Form  and  sculpture  like  that  of  the  Sageceratinae,  except  that  in  the  Carnitinae 
there  is  a  tendency  towards  the  development  of  ribs  and  knots.     The  septa  are  no 


Fig.  1191. 

Pseudosageceras  intermontanum  H.  and  S. 
Lower  Trias  ;  Idaho,     x  3/^. 


Fig.  1192. 

Sagcceras  haidingeri  (Hauer).     Upper  Trias  ; 
Hallstadt,  Austria. 

Fig.  1193. 

Septa  of  Arthaberites  alexandrae  Diener.     Middle 
Trias  ;  Alps  (after  von  Arthaber). 


longer  lanceolate,  but  ceratitic  or  even  largely  digitate. 
lobes  is  Short,  but  usually  highly  complex.     This 
groiip  probably  serves  as  a  connecting  link  be- 
tween  the  Sageceratinae  and  the  Pinacoceratinae. 

Garnites  Mojs. ;  Procarnites  Art.;  Arthaberites 
Diener  (Fig.  1193);  LanceoUtes  Hyatt  and  Smith; 
Hauerites and  Bamhanagües  Mojs. ;  Bosnites  Hauer; 
Tihetites  Mojs.      Trias. 

Subfamily  D.     Pinacoceratinae  Mojsisovics. 
Forms  thin,  compressed,  with  acute  venters. 


The  adventitious  series  of 


Lobes  and  saddles  all  finely  digitate.    Adventitious 
and  auxiliary  lobes  numerous. 

The  Pinacoceratinae  reach  the  highest  degree 
of  complication  of  the  septa  found  in  any  group 
of  Ammonites.  The  general  plan  of  their  septa 
suggests  a  derivation  from  the  Carnitinae,  and 
through  them  from  either  Hedenstroeminae  or 
Sageceratinae.      It  is  also  possible  that  the  sub- 


Pinacoceras  layeri  (Hauer).     Upper  Trias  ; 
Rötheistein,  near  Aussee,  Austria. 


636 


MOLLUSCA 


PHYLUM  VI 


gi-oups  imder  tlie  Pinacoceratidae  may  have  no  near  kinship  with  each  other  but 
niay  ratlier  be  inofely  phylogerontic  developments  in  different  Stocks. 
Pinacoceras  Mois.  (Figs.  1194,  1195);  Placites  Mojs. 

AtlL  EL 


Pinacoceras  metternichi  (Hauer).     Keuper  ;  Someraukogel,  near  Hallstadt,  Austria. 
Suture-line  reduced  (after  Hauer). 

Family  9.     Glyphioceratidae  Hyatt. 

Form  robust  and  involute,  or  evolute  and  trapezoidal  in  section.  Body-chamher  long. 
Labial  constrictions  always  present.  Spiral  ridges  often  present,  especially  on  the  venter. 
External  septa  someivhat  like  those  of  the  Primordialinae,  but  the  dorsal  or  internal  septa 
have  narrow  saddles  and  an  interior  lateral  lobe  on  either  side  of  the  pointed  anti- 
siphonal  lobe. 

Siphuncle  sniall,  and  funnels  generally  prosiplionate.  Aperture  iisually  with 
hyponomic  siniis,  but  some  species  liave  ventral  crests  diiring  ephebic  stages.  Shells 
smootli,  tuberculated  or  costated,  but  costae  do  not  cross  the  venter  as  a  rule.  Venter 
sonietimes  with  well-niarked  longitudinal  ridges. 

This  group  is  proba})ly  descended  from  the  Cheiloceratidae,  and  is  the  ancestral 

stock  of  the  Tropitidae  and  the  Arcestidae, 
possibly  also  of  the  Ptychitidae.  Muenstero- 
ceras,   Gastrioceras  (Figs.  1196,   1197),  Glyphio- 


Fiti.  1196. 

Gastrioceras  jossae  (M.  V.  K.).     Permo- 
Carboniferous  ;  Artinsk,  Ural. 


Fig.  1197. 

Ga'itrioceras  (Ziade?>ui(Qoldf.). 
Lower  Carbon iferous  Lime- 
stone ;  Choquier,  near  Liege, 
Belgium. 


Fig.  1198. 

GlypMoccras  sphaericum 

(Qoldf.).  Lower  Carboniferous 
Liniestone  ;  Suttrop,  West- 
phalia. 


Fig.  1199. 

Paralegoceras  newsovii 
Smith.         Goal      Measures  ; 


Arkansas. 
Smith). 


X  1/2  (after  J.  P. 


ceras  (Fig.    1198),  Paralegoceras  (Fig.    1199),   Schistoceras   Hyatt;    Pericyclus  Mojs.; 
Pronanmtes  Hang.  ;  Praeglyphioceras  Wedekind.     Devonian  and  Carboniferous. 


Family  10.     Thalassoceratidae  Hyatt. 
Forms  robust,  involute,  laterally  compressed.     Septa  from  yoniatitic  to  ceratitic  to 


CLARS  V 


CEPHALOPODA 


6?/ 


complex  digitale,  hut  always  with  few  lobes  and  saddles ;  auxiliary  series,  if  present, 
short ;  adventitious  series  consisting  of  not  more  than  one  lobe. 


Fio.  1201. 


Septa  of  Thalaasoceras 
phillip.n  Gemmel.  Permiaii ; 
Sicily  (after  Geminellaro). 


Fio.  1202. 

Septa  of  Ussuria  waageni  Hyatt  and  Smitli. 
Lower  Trias  ;  Idaho. 


of   tlie    Devonian  and  Lower 


Fig.  1200. 

Dimorphoceras  texanum  Smith.     Goal 
Measures  ;  Texas,    x  i/i  (after  J.  P.  Smith). 

This  familj  is  probably  derived  from 
Carboniferous.  There  is  a 
general  resemblance  to  the 
development  of  the  Canii- 
tinae,  in  tlie  formation  of 
adventitious  lobes,  but 
there  is  probably  no  kinship 
with  that  group, 

Dimorphoceras  Hyatt 
(Fig.  1200).  Carboniferous. 
Thalassoceras  Genim.  (Fig. 
1201).  Permian.  Ussuria 
Diener  (Fig.  1202).  Lower 
Trias.  Sturia  Mojs.  Alpine 
Trias. 


Family  11.    Ptychitidae 
Mojsisovics. 

Similar  in  aspect  to 
the  more  robust  forms  of 
Meelcoceratidae,  but  having 
subacute  venters,  more  com-  Fio- 1203. 

vlex  SUtureS    and  the  auxil-    Ptychifes  flexuosiis'M.oisi.  (  =  Ammo)iites  studeri  ümifr  it.-p.).     Muschelkalk; 
■^  •       '       •  7  .  Schreyer  Alp,  Salzburg,  Austria. 

lary  series  straighter. 

Ptychites  (Fig.  1203),  Japonites  and  Nannites  Mojs.;  Parannites  Hyatt  and  Smith. 

Owenites  Hyatt  and  Smith.     Trias. 


638 


MOLLUSCA 


PHYLÜM  VI 


Family  12.     Tropitidae  Mojsisovics. 


Forms  usualhj  robust,  hut  ranging  from  compressed-discoidal  to  keg-shaped.  Body- 
chamher  long.  Surface  usually  highly  ornamented  with  rihs  and  Jcnots.  Septa  are 
goniatitic  in  some  reversionary  genera,  ceratitic  in  the  most  primitive  forms  known,  hut 
mostly  slightly  digitate.  There  are  no  adventitious  lohes,  and  not  more  than  one 
auxiliary  lohe. 

The  Tropitidae  are  derived  from  tlie  gastrioceran  branch  of  tlie  Glypliioceratidae, 
willi  such  forms  as  Protropites  and  Columhites  as  connecting  links. 


Siibfamily  A.     Tropitinae  Mojsisovics. 
Similar  to  the  Anarcestidae  in  the  ephebic  stage,  but  the  young  frequently  ha^ 


volutions  with  highly  trapezoidal  sections. 
section  of  a  System  of  longitudinal 
ridges  and  transverse  costae.  Sutures 
have  deep,  narrow  ventral  lobes  divided 
by  siphonal  saddles  with  peculiar  trun- 
cated  bases,  which  are  often  retained  in 
later  stages.  Sutures  in  ephebic  stages 
of  some  forms  are  similar  to  those  of 
Haloritinae ;  the  young  have  a  more  or 
less   prolonged  coronate   stage,  and   are 


Sliells  higlily  ornamented  by  the  inter- 

www* 


Fig.  1204. 

Margarites  jokelyi  (Hauer). 
Upper  Trias  ;  Sandling,  near 
Aussee,  Austria. 


Fio.  1205. 


Tropites  .iihlmllaiHs  (ILiuer).     Upper  Trias 
AussiM',  Auslvia.     l/j. 


Fig.  1206. 

Discotropites  sandlingensis  (Hauer).     Upper  Trias 

California  (after  Hyatt  and  Smith). 


trJfTt'^  ^^^■.  'l°S'  n-'^'"'  '^^'^  ""'  ^;  1149;  1205),  Paratropües  [Micro- 
(ropites),  BarrandeHe.,  Szih/lhtes  Mojs.;  Discotropite,  H.  and  S.  (Fig.  1206).     Trias. 


CLASS  V 


CEPHALOPODA 


639 


Subfamily  B.      Haloritinae  Mojsisovics. 

Shells  more  globose  and  more  involute  in  tlie  young  than  in  tlie  Tropitidae,  and 
usually  keelless,  but  having 
similar  volutions  in  a  niimber 
of  species  diiring  later  stages. 
Ornament  as  a  rule  simpler 
than  in  Tropitidae.  Aper- 
ture  usually  with  ventral 
crests,  but  these  are  primitive 
in  outline,  broad,  and  in  some 
species  scarcely  indicated  by 
the  lines  of  growth. 

Halorites   {Homerites), 


W^-> 


Fic.  1207. 

Juvavites  subinterruptus  Mojs. 
Upper  Trias  ;  California  (after  Hyatt 
and  Smith). 


Fig.  1208. 

Sagenites  herbichi  Mojs.     Upper  Trias  ;  California 
(after  Hyatt  and  Smith). 


JoviteSj  Parajuvavites,  Juvavites  (Fig.  1207),  {Anatomites,  Grieshachites,  Dimorphites), 

Miltites,  Metasibirites, 
Sagenites  {Trachy  sagenites) 
Mojsisovics  (Figs.  1208, 
1209).     Trias. 


l 


Fig.  1209. 

Septa  of  Sagenites  herbichi  Mojs.     Upper  Trias  ;  California 
(after  Hyatt  and  Smith). 


^^Wi 


Fio.  1210. 
Septa    of    Acrochordiceras    hyatti 
Meek.     Middle  Trias  ;  Nevada  (after 
Hyatt  and  Smith). 


Subfamily  C.     Sibiritinae  Mojsisovics. 
Forms  robust  and  highly  ornamented,  with  strong  lateral  ribs  and  knots.     Septa 


640 


MOLLUSCA 


PHYLUM  VI 


ranRing  from  ceratitic  U>  moderately  digitale.     This  group  is  probably  the  connecting 
link  between  the  Glypliioceratidae  and  the  Haloritmae. 

J^oXrtor«  Hyatt  (Fig.  1210) ;  HtepUnite.  Waagen  ;  S^hntes  Mojs.     Tnas. 

Subfamily  D.     Celtitinae  Mojsisovics. 

Forms  discoidal,  evolute  and  slender  in  most  gene.a.      In  primitive   forms  with 

stron»  umbüical  rite,  frequent  constrictions  and  low  whorls  resembhng  teemce,«. 

'^  Septa  always  consistiiig  ot    lew  iobes 

I  and   saddles,  ranging  from  goniatitic, 

;  through  ceratitic,  to  slightly  digitate. 

___^       ^te  Paraceltües       Gemm.       Permian. 

IHiiP^'V        W  Geltites  and  Tropiceltites  Mojs. ;   Golum- 

^^      'i        Wir  hites  Hyatt  and  Smith   (Fig.   1211); 

Proteusites   Hauer  ;    Margarites    Mojs. 
,  — -    ^>^  Trias. 

/ ' '^V  V^  V^~V^^  This  group  is  the  connecting  link 

/».     '"'  ■  '  \    "  «^  between  Gastrioceras  of  the  Paleozoic 

and  the  Tropitinae  of  the  Middle  and 
Upper  Trias. 


I 


/■■ymk-^ 


,^' 


qpirrr 


Fig.  1211. 


Columhites  parisianus  Hyatt  and  Smith.     Lower  Trias 
,    Idaho  (after  Hyatt  and  Smith). 


Fig.  1212. 

Agathiceras  ciscoense  Smith.     Goal 
Measures  ;  Texas  (after  J.  P.  Smith). 


Family  13.     Arcestidae  Mojsisovics. 

Forms  smooth,  involute,  rohust,  with  frequent  labial  constrictions.  Body-chamher 
long.  Septa  ranging  from  goniatitic,  to  complex  digitate,  hut  alvjays  with  a  tendency 
towards  the  multiplication  of  the  lateral  lohes,  hoth  external  and  internal.  This  family 
is  undouhtedly  derived  from  the  gastrioceran  hranch  of  the  Glyphioceratidae,  hut  may 
he  polyphyletic,  inasmuch  as  hoth  Agathiceras  and  Schistoceras  may  he  radicals  of 
suhgroups. 

Subfamily  A.     Pop anoce  ratin ae  Hyatt. 

Forms  very  robust  and  involute.  Septa  relatively  simple,  ranging  from  goniatitic 
(Agathiceras),  though  slightly  serrated  (Stacheoceras),  but  never  becoming  completely 
digitate.  This  is  the  oldest  and  the  most  primitive  group  of  the  Arcestidae,  and  pro- 
bably branched  out  from  Schistoceras,  with  Stacheoceras  as  the  connecting  link. 


CEPHALOPODA 


C41 


Agathiceras  Gemin.  (Fig.  1212).     Carboniferoiis.     Stacheoceras  Gemm.  (Fig.  1213). 
Carboniferous  and  Permian.     Popanoceras  Hyatt  (Fig.  1214).     Permian,     Parapopano- 


iuff»w'f"fTff  1  ^ 


Fio.  1213. 

Septa  of  Stacheoceras  ganti  Smith.     Goal 
Measures  ;  Texas  (after  .T.  P.  Smith). 


fff^ffwwlf 


Fig.  1214. 

Popanoceras  multistriatum  Gemm. 
Permo  -  Carboniferous  ;  Sosio,  Sicily. 
^/s  (after  Gemmellaro). 


Fio.  1215. 

A,  Megaphyllites  insectus 
Mojs.  Upper  Trias  ;  Sand- 
ling,  near  Aussee,  Austria. 
jB,  Suture-line  of  M.  jarlias 
(Münster). 


Fig.  1216. 

Septa  of  Megaphyllites  haugi  Hyatt  and  Smith.     Middh^ 
Trias  ;  California. 


Fig.  1217. 
LoUtes     delphinocephalus     (Hauer).      Upper 
Trias  ;  Sandling,  near  Aussee,  Austria.     A,  B, 
External    aspect.       ü,    Median    section.      1), 
Suture-line,  i/i. 


Fig.  1218. 

Lobites  pisum  (Münster). 
Keuper  (Carniolan)  ;  St. 
Cassian,  Tyrol. 


ceras  Hang  ;  Megaphyllites  Mojs.  (Figs.  1215,  1216).     Trias  ;  Enrope.     (?)  Lobites  Mojs 
(Figs.  1217,  1218).      Trias;  Enrope. 

VOL.  I  2  T 


642 


MOLLUSCA 


PHYLUM  VI 


Subfamily  B.     Cyclolobinae  Zittel. 

Forms  as  a  rule  mucli  larger  and  witli  more  complex  septa  than  in  the  Popano- 
ceratinae.  There  is  a  distinct  tendency  towards  a 
phylloid  development  of  the  saddles.  This  subfamily 
probably  came  from  the  Popanoceratinae,  although  the 
most  primitive  and  oldest  genus  assigned  to  the  groiip, 
Shumardites,  almost  certainly  is  descended  directly  from 
Schistoceras. 

Shwnardites  Smith  (Fig.  1219).  Carboniferous.  Gyclo- 
lohus  Waagen  (Fig.  1220);  Waagenoceras  Gemm.  (Fig. 
1221).     Permian. 


Fio.  1219. 


Septa  of  Shumardites  simon(lM 
Smith.    Goal  Measures  ;  Texas. 


Subfamily  C.     Arcestinae 
Mojsisovics. 


This  comprises  smooth,  globose, 
deeply  involute  anarcestean  forms, 
discoidal  only  in  primitive  genera. 
Gerontic  living  Chamber  usually  more 
or  less  contracted  laterally,  becoming 
sometimes  subacute  at  the  venter  ;  in 
extreme  age  depressed,  and  truncated 
or  concave  at  the  aperture.  The 
latter  has  typically  in  the  ephebic 
stage  a  low  broad  ventral  crest,  but 
loses  this  in  the  paragerontic  sub- 
stage,  and  acquires  a  ventral  sinus 
simulating  that  of  Paleozoic  and  more 
primitive  forms,  Saddles  and  lobes 
completely  divided  by  more  or  less 
complex  marginals,  the  monophyllic 
outline  being  completely  obscured 
except  in  the  young,  and  in  dorsal 
sutures  of  some  species.  Siphonal 
saddles  long,  and  not  very  deeply 
incised  by  marginal  lobes.  Antisi- 
phonal  lobe  bifid  or  trifid,  and  com- 
plex in  specialised  forms.  Other 
dorsals  may  also  become  quite  com- 
plex, and  as  a  rule  are  completely 
divided,  although  of  course  simpler 
,  .     ^,  than    the    external    sutures.      Dorsal 

in  epheWc  sta  e^''''''^  '''''^^^'  ^^""'^  °^  ^^'  Popanoceratinae.     Funnels  prosiphonate 

Sphingites     Arcestes  JFigs.    1139,    1222),    Stenarcestes,    Proarcestes,    Pa.'arcestes, 
Ptycharcestes,  Joanmtes  (Fig.  1223),  Didymites  Mojs.  (Fig.  1224).      Trias. 


Fig.  1220. 


Cyclolöbus  stachei  Gemm.     Permo-Carboniferous  ; 
Sosio,  Sicily  (after  Gemmellaro). 


Fig.  1221. 


Septa  of  Waagenoceras  Ulli  Smith.    Permian  • 
Texas,     x  1/2  (after  J.  P.  Smith). 


Family  14.     Cladiscitidae  Mojsisovics. 


..Jr    Tli  '^1  '7^7f  ^'  ^^'^^  '^^^^Vtly  rounded  ventral  Shoulders  and  flattened 

nndTrJ,n^fr'     T  V    ^'  '^^''^^^^^on  of  the  aperture,  and  no  labial  constrictions. 
Bodychamher  long.     Surface  sp^rally  striated.     Lobes  and  saddles  numerous,  deeply  and 


CLASS  V 


CEPHALOPODA 


643 


Fio.  1222. 

Arcestes  intuslabiatus  Mojs.     Upper  Trias  ;  Steinbergkogel,  near  Hallstadt,  Austria. 
A,  B,  Externa!  aspect.     C,  Median  section.     D,  Suture-line. 


Fig.  1223. 

Joannites  cymhiformis  Wulfen.  Upper  Trias  ;  Raschberg, 
near  Aiissee,  Austria.  Natural  mciild  showing  the  living 
Chamber  (after  Mojsisovics). 


finely  divided,  arranged  serially. 
The  stems  of  the  saddles  are  long 
and  narroiv,  divided  anteriorly  into 
two  or  four  branches. 

The  shape  and  ornamentation 
of  the  Shell  suggest  a  derivation 
from  Agathiceras  of  the  Carboni- 
ferous  and  Permian,  biit  no  con- 
necting  links  are  known. 

Gladiscites  Mojs.  (Hypocladiscites 
Mojs.)  (Fig.  1225).     Trias. 

Family  15.     Meekoceratidae 
Waagen. 

Gompressed    discoidal    and    in- 

Fio.  1224. 

Suture-line  of  Didymites  suhglohus 
Mojs.  Upper  Trias  ;  Someraukogel, 
near  Hallstadt  (after  Mojsisovics). 


volute  forms.  Surface  nearly  smooth,  radial  folds  heing  often  present,  but  constrictions 
and  spines  always  absent.  Body-chamber  short  Septa  simple  goniatitic  in  primitive 
forms,  becoming  ceratitic  in  most  genera^  but  rarely  reaching  a  digitate  stage  of  com- 
plexity  in  even  the  most  specialised  groups.      The  ventral  lobe  is  divided  in  all  forms ; 


644 


MOLLUSCA 


the  dorsal  (antisiphonal)  lohe  'is  undivided  in  the  most  primitive 

B 


PHYLUM  VI 

forms,  and  hifid  in  the 
more  syedalised  groups. 

The  entire  family 
is  supposed  to  have 
beeil  derived  from 
Lecanites,  and  tlirough 
tliat  geiius  to  liave  been 
connected  witli  Nomis- 
moceras  of  tlie  Carboni- 
ferous,  and  Gephyroceras 
of  the  Devonian. 


Fig.  1225. 

Cladiftcitrs  tornatus  (Bronn).     Upper  Trias  ;  Steinbergkogel,  near  Hallstadt,  Austria. 
A,  B,  Lateral  and  anterior  views.     (',  Suture-line. 


Subfamily  A.     Lecanitinae  Hyatt, 

Primitive  discoidal  Shells  like  those  of  the  Prolecanitidae,  with  short  rounded  entire 
saddles  and  lobes  like  those  of  Prolecanites,  but  ventral  lobes  divided  by  short  coin- 
paratively  broad  and  entire  siphonal  saddles.     There  are  all 
stages  in   the  development  of   these  saddles,  so    that  their 
aspect  is    rather'  variable.      There    are    as  a    rule  but  two 
principal  lateral  saddles  and  lobes,  with  one  auxiliary  saddle 
and  shallow  lobe  on  either  side  in  primitive  species,  but  in 
others  the  number  of  auxiliaries  may  be  considerably  iii- 
creased.     Antisiphonal  lobe  entire,  and  often 
long  and  acute.     The  zygous  dorsal  lobes  are 
very  sliglit   so  far  as    known,   and    entire ; 
merely  marginals  in  the  dorsal  saddles. 

Paralecanites  Diener  (Fig.   1226).     Per- 

iiiian  and  Triassic.     Lecanites  Mojs. ;  Kyma- 

tites,      Parakymatites     Waagen ;      Proavites 

eryx   Arthaber;  Badiotites  Mojsisovics  (Fig.  122V). 

Trias. 


Fig.  1226. 


Fig.  1227. 


H. 


Paraleamites     arnoldi 
and  S.     Lower  Trias  ;  Idaho 
(after  Hyatt  and  Smith). 


Badiotites 
(Münst.).    Keui)er 
St.  Cassian,  Tyrol. 


Subfamily  B.     Meekoceratinae  Waagen. 

Shells  smooth,  compressed,  discoidal  and  involute,  and  as  a  rule  with  narrow  and 
more  or  less  flattened  venter.  Sutures  in  many  forms  have  a  tendency  to  extend  the 
inner  lateral  saddles  or  lobes,  and  to  develop  a  corresponding  series  of  auxiliaries  -, 
and  this  is  carried  to  an  excessive  extent  among  some  highly  involute  shells.  The 
ventral  lobes,  however,  are  apt  to  remain  broad  and  shallow;  their  arms  become 
highly  denticulated  except  in  the  Lecanitinae  where  they  are  narrow  and  rounded. 
Saddles  entire  and  generally  somewhat  elongate  and  linguiform,  but  plainly  of  the 
Lecanites  type.     Antisiphonal  lobe,  so  far  as  known,  long,  narrow  and  bifid.     Ex- 


CLASS  V 


CEPHALOPODA 


645 


tremities  or  dorsal  sutures  piodiiced  and  corresponding  witli  the  inner  parts  of  the 
external  sutures. 

Meekoceras  }iyaitt  (Fig.  1228);  Nicomedites  Tou\a  (KonincMtes) ;  Clypeoceras  nom. 
nov.  (Aspidites  Waagen),  of  whicli  the  type  is  A^idites 
süperb  US  Waagen  ^  ;  Proptychües  Waagen.     Triassic. 

Family  16.     Gymnitidae  Waagen. 


Smooth,  compressed,  discoidal  shells  with  rounded 
venter  in  primitive  forms,  hecoming  involute  with  acute 
venter  in  specialised  species.  Septa  not  reaching  ahove 
the  ceratitic  steige  of  development  in  most  genera,  hut  nof 
remaining  in  the  goniatitic  steige  in  any  known  genera. 
Sutures  in  specialised  groups  similar  in  convexity  and 
general  aspect  to  those  of  the  Pinacoceratidae,  hvJ 
having  peculiar,  highly  inclined  auxiliaries  which  ar- 
developed  apparently  from  marginals  on  the  umhilical 
sides  of  the  saddles ;  no  corresponding  adventitious 
inflections.  Siphonal  saddle  similar  to  that  of  Meeko- 
ceratidae,  and  arms  of  the  ventral  lohe  narrow.  First 
lateral  saddles  are  dependent  on,  or  attached  to  the 
large  siphonal  saddles,  and  often  simulate  adventitious 
saddles. 

Gymnites  Mojs.   (Fig.    1229);    Buddhaites   Diener; 
Anagymnites  Hyatt.      Type  A.  {Gymnites)  lamarcki  (Diener), 
Type  P.  (Plac.)  sakuntala  (Mojs.).     Trias. 

Xenodiscus  and  Xenaspis  Waagen.      Permian  and  Trias.     Ophiceras  Griesbach  (Fig. 
1230).     Trias.     Flemingites  Waagen  (Fig.  1231). 
Trias.    Japonites  Mojs.    Trias.    Europe  and  Asia. 

The  Gymnitidae  are  commonly  regarded  as  a 
subfamily  under  the  Ptychitidae,  but  they  are 


Meekoceras 
Lower   Trias ; 
Hyatt  and  Smith). 


Fig.  1228. 

muslibachanum,    White. 
Idaho.      X  1/2   (after 


Paragymnites  Hyatt. 


Fig.  1229. 

Gymnites  palmai  Mojs.     Muschelkalk 
Schreyer  Alp,  near  Oosau,  Austria. 


Ophiceras  jacksoni  H.  and  S.     I.ower  Trias 
Idaho  (after  Hyatt  and  Smith). 


more    probably    an    offshoot    from    the   Lecanitinae,    and    through    them    from    the 
Gephyroceratidae. 
1  The  nairie  Aspidites  was  preoccupied  when  Waagen  usecl  it,  and  a  new  one  becomes  necessary. 


646 


MOLLUSCA 


PHYLUM  VI 


Family  17.     Hungaritidae  Diener. 
Form  involute,  laterally  compressed,  with  keeled  venter.     Surface  often  ornamented 


Idaho  1/2  (after  Hyatt  and  Smith), 


\> 


Fig.  1232. 

Inyoites  oweni  H.  and  S.     Lower  Trias  ;  California 
(after  Hyatt  and  Smith). 


with  folds,  rihs  or  hnots.  Body 
Chamber  short.  Septa  usually  cera- 
titic,  not  reaching  the  digitate  stage 
in  any  genera,  hut  persisting  in  the 
goniatitic  stage  in  Beneckeia. 

This  group  is  not  regarded  as 
a  side  branch  from  the  Meekoce- 
ratidae,  but  as  an  old  and  persistent 
stock,  Coming  down  with  little  modification  from  the  Gephyroceratidae,  probably 
from  the  keeled  form  Timanites.  The  Hungaritidae  have  been  confused  with  the 
group  of  keeled  Geratites,  and  also  with  compressed  members  of  the  Tropitidae,  but 
the  resemblance  is  one  of  convergence,  and  bespeaks  no  near  relationship. 

Hungarites  Mojs. ;  Otoceras  Griesbach.  Permian  and  Trias.  Beneckeia  Mojs. ; 
Inyoites  Hyatt  and  Smith  (Fig.  1232);  Dalmatites  Kittl.  Permian  and  Trias. 
Eutomoceras  Hyatt  {Halilucites  Diener).     Trias. 


Family  18.     Ceratitidae  Mojsisovics. 


Forms  evolute  to  involute^  laterally  compressed  to  robust  and  rounded.  Surface 
usually  ornamented  with  folds,  ribs,  knots,  spines  or  tubercles.  Venter  in  some  genera 
provided  with  a  keel,  in  others  with  a  median  furrow  ;  and  occasionally  biangidar.  Body 
Chamber  rather  short.  Septa  ranging  from  the  goniatitic  stage  in  some  arrested  or  re- 
versionary  forms,  through  the  typical  ceratitic  stage,  to  complex  digitation. 

This  family  may  be,  and  probably  is,  polyphyletic,  but  a  large  part  of  it,  including 
the  typical  Geratites,  seems  to  have  been  derived  from  Meekoceras  or  from  some  member 
of  that  group.  Only  the  more  primitive  members  of  Geratites  show  a  youthful  stage 
similar  to  Meekoceras,  but  there  seems  to  be  a  perfect  intergradation  between  the  more 
complex  species  of  Meekoceras  and  the  more  primitive  species  of  Geratites. 

Subfamily  A.     Ceratitinae  Mojsisovics. 

Primitive  forms  are  discoidal  or  involute,  but  stout-whorled  and  keelless,  becoming 
more  compressed,  and  having  a  broad,  slightly  elevated  median  ventral  ridge  in  more 
specialised  genera.     Sides  have  at  least  one  line  of  nodes  in  primitive  forms,  and  are  more 


CLASS  V 


CEPHALOPODA 


647 


Ol"  less  conii)letely  costated  witli  several  lines  of  tabercles  in  specialised  shells.  Sutures 
in  thc  young  and  in  primitive  genera  liave  a  magnosellarian  aspect,  but  when  the  broad 
internal  saddles  beconie  divided,  the  internal  inflections  resemble  those  of  Lecanitinae. 


Fio.  1233. 

Cemtitesnodomsdenmn.  Muschelkalk;  Wurzburg,  Bavaria.  yl,  7?,  Conch,  Vi-  a  Lcfthalf  of  suture-line. 
D,  First  and  second  lateral  saddles  and  auxiliaries  to  left  of  line  of  Involution  (n);  half  of  dorsal  suture-lina  to 
right.     (äL,  Antisiphonal  lobe  ;  other  lettering  as  in  Figs.  1145,  1146.) 


In  primitive  forms  (OleniMtes)  the  saddles  are  broad  and  very  shallow ;  lobes  entire, 
and  ventral  lobe  divided  by  a  larviform  siphonal  saddle,  which  is  sometimes  entire. 

The  large  nodes  and  stout  volutions  of  primitive 
forms  indicate  parallelism  with  Stephanites.  Saddles 
and  lobes  have  the  typical  ceratitic  outlines,  as  a  rule, 
but  in  some  forms  the  auxiliary  line  may  be  extended  as 
in  the  Meekoceratinae.  Occasionally,  also,  costae  may  cross 
the  venter  as  in  Sibiritinae. 

Geratites  de  Haan  (Figs.  1233,  1234) ;  Danuhites  and 
Balatonites  Mojs. ;  Reiflincßtes  Arthab.  Gymnotoceras  and 
Olenikites  Hyatt.  Type  0.  {Bin.)  sjnniplicatus  (Mojs.). 
Keyserlingites  Hyatt.  Type  K.  (Geratites)  subrobustus 
Mojs.  Beyrichites  Waagen.  Siibgenera :  Hollandites  and 
Phülippites  Diener.      Trias. 


Subfamily  B.     Tirolitinae  Mojsisovics  (pars). 


Fig.  1234. 

Cemtitrs  (rinodosus  Hauer.     Mus- 

Compressed,  discoidal  or  involute   shells  reseml)ling   chelkalk;  Bakony,  Hungary  (after 

Dinaritinae    in  thoir  sutures  and   having   entire  saddles   '  «J^'^omcs). 

and  slightly  denticulated  lobes.      Ventral  lobe  may  remain  entire  until  a  late  stage 

in  some  forms,  but  as  a  rule  it  is  divided,  and  the  siphonal  saddle  is  small  and  often 


648  MOLLUSCA  thylüm  vi 

entire.     Shells  have  a  line  of  nodes  on  the  ventro-lateral  angles,  and  the  venter  is 

invariably  smooth  and  convex. 

Includes  Tirolües  (Fig.  1235)  and  MetatiroUtes  Mojs.,  froni  tlie  Alpine  Trias  and 
froiii  Idaho.  The  siibfamily  of  Clydonitinae  has  siitnres 
similar  to  Tirolües,  biit  costae  interriipted  on  the  venter, 
which  is  often  channelled.  Includes  Gkjdonites  and  Eremites 
Hauer  ;  and  Ectolcites  Mojs.     Trias. 

Subfamily  C.     Dinaritinae  Mojsisovics  ^pars). 

Sutures  resembling  Tirolües  in  having  only  two  broad 
saddles,  one  pair  of  first  lateral  lobes,  and  inconiplete  lobes 
at  the  umbilicus.  Shells  smooth,  or  with  coarse  folds 
most  prominent  at  the  umbilical  Shoulders  ;  sides  more  or 
less  flattened  or  planoconvex,  and  venter  rounded. 

Dinarites  Mojs. ;  Cuccoceras  Diener.     Trias. 

Subfamily  D.     Buchitinae  Hyatt. 

Primitive  forms    similar    to  Celtitinae,  with    smooth 
elevated  venter  ;  more  specialised  shells  with  slight  keel  on 
Tirolües   cassianus   (Quenst.)   the  narrow  venter,  and  simple  costae  or  folds  on  the  sides. 
Lower  Trias ;  Grones-Hof,  near   Sutures  have  entire  outlines,  or  lobes  but  slightly  denti- 

st  Cassian  Tvrol.  o       ./ 

culated ;    and   when   the   saddles    are    completely  divided 
their  marginals  are  small.     Sutures  otherwise  similar  to  those  of  Dinaritinae,  and  the 
young  have  a  Dinarites  stage.     Antisiphonal  lobe  entire  and  bifid  in  some  forms. 
Buchües,  Helictites,  Phormedites,  Parathishites  and  Glyphidites  Mojs.     Trias. 


Fig.  1235. 


Subfamily  E.     Arpaditinae  Hyatt. 

Differs  from  the  Buchitinae  in  the  tendency  to  form  channelled  venters  bordered 
by  two  ridges,  which  may  be  either  tuberculose  or  smooth. 

Ärpadües  (Fig.  1236),  Klipsteinia,  Dütmarites,  Muensterües,  Steinmannües,  Dafli- 
nües,    Dionites,    Brepanües,    Heraclües,    Guemhelües, 
Cyrtopleurües  and  Acanthinites  Mojs.     Trias. 


Subfamily  F.     Trachyceratinae  Hyatt. 


Discoidal  and  involute  shells  with  well-defined  and 
often  profusely  tuberculated  costations  which  are 
interrupted  on  the  ventral  aspect  by  a  smooth  zone 
or  Channel.  This  may  in  some  specialised  forms 
becorae  a  d  istin  et  Channel  bordered  by  tuberculated 
ridges.  Lobes  and  saddles  completely  divided  by 
marginals,  but  these  do  not  become  very  long  nor 
complex. 

Distichites,  Trachyceras  (Fig.  1237),  Protrachyceras  (Fig.  1238),  AnolcÜes,  Sand- 
hngites,  Siremtes,  Anasirenites,  DiplosirenÜes  and  Glionües  Mois.  (Figs  1239,  1240). 
Trias.     (?)  Hesperites  Pompeckj.     Rhaetic. 

Subfamily  G.     Choristoceratinae  Hyatt. 
Discoidal  ammoniticones  in  primitive  forms,  becoming  uncoiled  phylogerons,  and 
finally  even  complete  baculiticones  in    the  most  specialised   species.      Sutures  also 


Arpadites  cinensis  Mojs.     Keuper 
Esino,  Lombardy. 


CLASS  V 


CEPHALOPODA 


649 


phylogerontic,   liaviiig   oiily  six   entire  or  vciy  faintly  denticulated    lobes,  and    six 
entire  saddles.      Ventral  lobe  divided,  and  tlie  antisiphonal  either  entire  or  bifid  at 


Fig.  1237. 

Trachycerasaustriacum  Mojs.    Upper  Trias  ; 
Rötheistein,  near  Aiis.see,  Austria. 


Fig.  1238. 


Protrachyceras  archelaus  Laube.     Upper  Trias  (Norian) ; 
Bakony,  Hungary  (after  Mqjsisovics).     1/2- 


Fig.  1239. 

(Jlionites  fairhanksi  H.  and  S.     Upper  Trias  ; 

California  (after  Hyatt  and  Smith). 


Fig.  1240. 
Septa  of  Clionites  fairbanlcsi  H.  and  S.     x  1/2- 


./Vr^y- 


Fig.  1241. 

Polycydus  nastur- 
tium  (Dittmar). 
Keuper ;  Sandling, 
near  Aussee. 


FiO.  1242. 

Choristoceras  marshi 
Hauer.  Rhaetic ;  Kendel- 
engraben  am  Osterhorn, 
near  Salzburg. 


its   extremity.       Dorsal    lobes    and    saddles    otherwise    entire.       Connected    through 
Polycydus  with  Buchites,  according  to  Mojsisovics. 

Polycydus  (Fig.  1241),  Peripleurites  Mojs.;  Choristoceras  (Fig.  1242),  Rhahdoceras 
Hauer  (Fig.  1243).     Trias. 


650 


MOLLUSCA 


PHYLUM  VI 


/iW^K 


Siibfamily  H.     Cochloceratinae  Hyatt. 

Turriliticones  vvith  costae  similar  to  those  of  the  preceding  groiip,  but  more  or  less 

asymmetrical  in  conseqiience  of  the  asymmetry 
of  the  spires.  Lobes  reduced  to  foiir  in  niimber, 
and  there  are  other  phylogerontic  suppressions, 
Funnels  monochoanitic,  collars  absent. 

Gochloceras  Hauer  (Fig.  1244) ;  Paracochloceras 
Mojs.     Trias. 

Family  19.     Phylloceratidae  Zittel. 


Fig.  1243. 

RhaJ)doceras  suessi 
Hauer.  Keuper  ; 
Sandling,  near 
Aussee  (after 
Hauer). 


Shells  smooth,  wiih  radial  Striae  or  weak  folds. 
Form    compressed,   with    rounded    venters.      Body 
,,  "  ,     -  ,,.   Chamber  tahing  up  one-half  to  three-fourths  of  the 


Hauer.  Sandling,  last  volution.  Aperture  simple,  with  short  ventral 
Hauer)."^'"'^^  ^^  crest.  Lohes  and  saddles  numerous,  decreasing  in 
size  towards  the  umhilicus.  In  primitive  genera  the 
have  monophyllic  bases  resembling  those  of  the  Popanoceratinae,  but  in  the  more 
specialised  groups  only  the  marginal  saddles  retain  the  rounded  outline,  the  others 
becoming  deeply  divided,  although  always  remaining  phylloid  in  termination. 

Monophyllites    is    the   oldest   and    most    primitive  of   the   Phylloceratidae,    and 


fffP 


V^-; 


Fic.  1:^45. 

Mouüphyliitcs  dmonyi  (Hauer).     Upper  Trias 

Rötheistein,  near  Aussee,  Austria. 


Fig.  1246. 

Monophyllites  hillingsicmns  Gabb. 
Middle  Trias  ;  Nevada  (after  Hyatt 
and  Smith). 


probably  connects  the  family  with  Nomismoceras  or  some  other  derivative  of  the 
Gephyroceratidae.  The  resemblance  of  Phylloceras  to  the  Permian  Arcestidae  is 
purely  one  of  convergence,  for  neither  the  young  of  Phylloceras  nor  the  adiilts  of 
Monophyllites  resemble  any  genera  of  the  Arcestidae.  But  the  young  of  Phylloceras  are 
like  adult  Monophyllites,  and  the  young  of  Discophyllites  are  at  first  like  Nomismoceras, 
and  the  adolescent  stages  like  Monophyllites.  The  developnient  of  Monophyllites 
itself  has  not  yet  been  studied. 


CLASS  V 


CEPHALOPODA 


651 


The  fainily  of  tlie  Phylloceratidae  is  tlie  most  persistent  and  the  longest-lived 
aniong  the  Amnionoids,  being  continuoiis  from  the  Permian  to  the  Upper  Cretaceous. 

Subfaniily  A.     Monophyllitinae  Smith. 

Sliells  compressed,  discoidal,  evolute.  Septa  with  primitive  monopliyllic  saddles, 
and  more  regulär  in  the  relative  size  of  the  lobes  and  saddles  than  the  succeeding 
group.  Antisiphonal  lobe  bifid,  but  otherwise  entire.  MonophylUtes  Mojs.  (Figs 
1245,  1246)  {Mojsvarites  Pompeckj);  Discophijllites  Hyatt  (type  Lytoceras  patens  Mojs.). 
Triassic.  Discophyllites  forms  a  connecting  link  with  the  Phylloceratinae,  and  might 
with  eqiial  propriety  have  been  classed  with  that  group. 


Subfamily  B.     Phylloceratinae  Zittel. 
Form  usually  involute.     Septa  very  complex,  with  the  saddles  deeply  digitate, 


Fio.  1248, 


l'hylloceras  heterophyllum  (Sowb.).     Upper 
Lias ;  Whitby,  Yorksliire. 


Fhyüoceras  ptychoicum  (Quenstedt).    Tithonian  ;  Stranibei^, 
Moravia.     AL,  Antisiphonal  lobe. 


652 


MOLLUSCA 


PHYLUM  VI 


but  retaining  the  phylloid  ending,  and  witli  the  marginal  saddles  retaining  the 
monophyllic  outlines.  Antisiplional  lobe  with  entire  sides,  or  with  only  one  pair  of 
lateral  branclies,  and  extremities  bifid. 

Rhacophyllites  Zittel  (Fig.  1247);   EitphylUtes  Wähner  ;  Phylloceras  Suess  (Figs. 


ifi  a5  «•*  a3    a2     ai  l 

Fio,  1250. 

Suture-line  of  Phylloceras  nüssoni  (Heb.), 
Upper  Lias. 
SL,  Ventral  or  slphonal  lobe  ;  L,  First,  and  l,  Second  lateral  lobes 


Fig.  1251. 


l    Li  AL 


Sutiire-line  of  Sowerhiceras  tortisulcatum  (d'Orb.) 
(after  Quenstedt). 

^     ^  ai  -  6,  Inner  or  .so-called  auxiliary  lobes  ; 

ri^Line  of'involution  ;  Li,' Second  dorsal  lobe  ;  AL,  Antisiphonal  lobe. 

1140,  1248-1250) ;  Sowerhiceras  Paroni  and  Bon.  (Fig.  1251) ;  Dasijceras  Hyatt.  Type 
D.  (Phylloceras)  rakosense  (Herbicb).  Schistophylloceras  Hyatt.  Type  S.  (Phylloceras) 
aulonotum  (Herbich).  Geyeroceras  Hyatt.  Type  G.  (Phyll.)  cylindricum  (Geyer). 
Trarjophylloceras  Hyatt.  Type  T.  (Phylloceras)  heterophyllus-numismalis  (Qiienst.). 
Meneghiniceras  Hyatt.     Type  M.  (Phylloceras)  lariense  (Menegh.).     Trias  to  Cretaceous. 


Family  20.     Lytoceratidae  Neumayr. 

Shell  widely  umhilicate,  sometimes  forming  a  hose  or  snail-like  spiral,  sometimes 
even  hook-shaped.  Body  chamher  two-thirds  to  three-fourths  of  the  last  volution.  Aperture 
rounded,  whorls  little  emhracing.  Surface  often  ornamented  ivith  simple  rihs  or  rows 
of  knots.  Septa  deeply  divided,  with  usually  tvjo  lateral  lohes  and  an  auxiliary.  The 
first  and  often  the  second  lateral  lohes  and  saddles  are  deeply  hifid. 

In  all  probability  the  family  Lytoceratidae  is  not  monophyletic,  some  of  the 
Scaphites  and  other  degenerate  groups  Coming  from  different  Stocks.  The  Lytoceratinae, 
however,  appear  to  be  monophyletic,  and  to  liave  been  derived  from  Monophyllites. 


Subfamily  A.     Lytoceratinae  Mojsisovics  (pars). 

Incliides  only  closely  coiled,  discoidal  and  involute  shells  with  somewhat  prominent, 
often  crenulated,  transverse  bands  of  growth.  Antisiphonal 
lobe  with  two  long  internal  branches  bending  inwards  and 
attached  to  surfaces  of  the  septa.  Siphonal  lobe  short 
like  that  of  Phylloceras,  and  siphonal  saddles  narrow.  The 
first  lateral  saddles  small  and  short,  the  first  lateral  lobes 
much  longer  than  the  ventral.  Eeduction  of  lobes  along 
the  line  of  Involution  is  such  that  there  are  commonly 
only  six  to  eight  in  fuU-grown  shells. 

Lytoceras    Suess    (Thysanoceras    Hyatt)     (Figs.     1252, 
1253).      Jura  and  Cretaceous.      Älocolytoceras  Hyatt  (Fig. 
1254).     Type  Ä.  (Amm.)  germainei  (d'Orb.).    Pleurolytoceras 
Lytocera.^fimbriaium{Sovfh.).     Hyatt.       Type    P.    (Amm.)    hircinum    (Schloth.).       Jura. 

Middle    Lias  ;    Würtemberg.       m,  u     xr  j.      n       i  ^ 

Cross-section  (cf.  Fig.  1148).        ^  eiragonites  Kossmat ;  Gaudryceras  Grossouvre.     Cretaceous. 


Subfamily  B.     Macro8Caphitinae  Hyatt. 
Symmetrical,  closely  coiled,  discoidal    ammoniticones  during  \oimg  stages  (and 
persistently  so  in  primitive  forms),  but  becoming  uncoiled  in  gerontic  stages  or  earlier 


CEPHALOPODA 


653 


1253. 


Lytoceras  liebicji  (Oppel).     Tithonian 
Straraberg,  Moravia. 


in  tlie  ontogeny  of  phylogerontic  forms, 
and  fmally  straight  in  some  genera. 
Antisiphonal  lobe  sliort,  and  in  some 
genera  trifid.  Shells  have  constrictions 
and  large  costae  at  intervals,  but  no 
tubercles  at  any  stage. 

Macroscaphites  Meek  (Fig.  1255)  ; 
Leptoceras,  Costidiscus  Ulilig  ;  Tropaeiim 
Sowb. ;  Hamites  Parkinson  (Fig.  1256); 
Ptyclwceras  d'Orb.  (Fig.   1257);   Di-pty- 


i^tin 


Fig.  1254. 

Alocolytoceras  germainei  (d'Orb.). 
Upper     Lias  ;      Pinperdu,      near 
Salins,  Jura 


Fic.  12Ö5. 

Macroscaphites  ivanii  (d'Orb.). 
Upper  Neocomian  ;  Malleuewitz, 
Carpathia. 


Fio.  1256. 

Hamites  rotundatus  (Sowb.). 

Gault ;  Folkestone. 


Fic.  1257. 

Ptychoceras  puzo- 
sianum  (d'Orb.). 
Barremian ;  Vergons, 
Basses  Alpes. 


654 


MOLLUSCA 


PHYLUM  VI 


choceras  Gabb 


Fig.  1258. 

A,  Baculites  anceps  Lam.    B,  B.  faujasi 
Lam.    Upper  Cretaceous  ;  Maestricht.  t 


Fig.  1259. 

Suture-line  of  Diplomoceras  cylindraceum 
Defr.  Uppermost  Cretaceous  ;  Tresville, 
Manche. 


Oyrtochilus  Meek  {Scipionoceras  Hyatt) ;  Baculites  Lam.  (Fig.  1258). 

Diplomoceras      Hyatt      (Fig. 

1259).    Type  D.  (Harn.)  cylin- 

ß  draceum,  (d'Orb.).     Hamulina 

d'Orb.  (Fig.  1260,  A).  Cre- 
taceous. Baculina  d'Orb. 
Juras. 


Subfamily  C.     Turrilitinae 
Hyatt  {pars). 

A  heterogeneous  group 
of  turret-shaped  cones,  with 
Shells  highly  ornamented 
witb  ribs  and  tubercles.  In 
Turrilites  the  spire  is  sym- 
metrical  and  close-coiled  ;  in 
most  other  forms  it  is  un- 
symmetrical,  and  niore  or  less 
open.  The  relationship  of 
this  group  to  the  Lytocera- 
tidae  is  extremely  problema- 
tical. 

Turrilites  Lamarck.  (Fig. 
1261);  Heteroceras  d'Orb. 
(Fig.  1262);  Emperoceras 
Hyatt ;  Helicoceras  d'Orb. 
Cretaceous. 


Fig.  1260. 

A,  Hamulina  subcylin- 
drica  (d'Orb.).  B,  Suture- 
line  of  A.  lorioli  (Uhlig). 
Neocomian ;  Angles,  Basses 
Alpes  (after  Uhlig). 


Family  21.     Aegoceratidae  Neumayr. 

Form  discoidal,  mostly  widely  umbilicate.  Whorls 
smooth,  or  with  straight  radial  rihs  that  occasionally 
hifurcate  at  the  venter.  Aper- 
ture  without  lateral  ears. 
Venter  with  keel,  or  with  for- 
ward  pointing  crest.  Body 
Chamber  comprising  from 
three-fourths  to  more  thart,  a 
complete  revolution.  Suture 
line  not  deeply  digitale ; 
usually  with  only  two  lateral 
lobes  and  an  auxiliary. 

Subfamily  A.     Psilocera- 
TiNAE  Zittel. 

Widely  umbilicate, 
whorls  laterally  compressed, 
smooth  or  with  simple  ribs 
whicli    do     not     cross     tlie  fig.  1261. 

rounded  keelless  venter. 

The    Psiloceratinae     are 


Fig.  1262. 


GlnU^viiZJV''''''^'''    "^'P""^-        Heteroceras polyplomim  (Roemer). 
d'Orbigny).  '  """  ^  Upper  Cretaceouf ;  Haldem,  West- 


CLASS  V 


CEPHALOPODA 


6^ 


commonly  supposed    to  have  beeii  tlie   progenitors    of   all  the  other  Aegoceratidae. 

It  is,  however,  just  as  likely  tliat  they  are  a  degenerate  groiip,  reversioiiary  towards 

the  ancestral   radical.      Tliey  have    a  certain    re- 

semblance  to  Monophyllites,  which    has   given   rise  h^f^^iS'^^ 

to  the  idea  that  they  may  be  an  offshoot  from  the  r\     ^  ^,.v— w    ; 

Phylloceratidae.     This  too  is   improbable,  the  re- 

semblance  being  most  likely  a  convergence  pheno- 

menon. 

Psiloceras     Hyatt    (Fig.     1263);      Tmaegoceras 
Hyatt.     Lias. 

Subfamily  B.     Arietitinae  Zittel. 

Veiiter  with  strong  keel.      Form  evolute,  volu- 

tions  of  discoidal   forms  more   quadrate    than    in 

j)recediiig  faniilies,    and   often   with   a   channelled 

venter.      Costae  more  strongly  developed  as  a  rule, 

and  with  prominent  ventro- lateral  angles,  which 

are    sometimes    tuberculated.      Sutural  inflections 

reduced   in  number  and   complexity  as    compared 

with  preceding  families,  and  phylliform  marginals 

replaced    by    saddles    of    more    irregulär    aspect. 

Ventral  lobe  long  and  narrow,  with  corresponding 

siphonal  saddle.      Usually  only  two  pairs  of  large  lateral  saddles,  the  second   often 

the  most  prominent.     First  pair  of  lateral  lobes  large,  second  and  third  pairs  snccessively 

smaller ;  third  and  fourtli  pairs  of  saddles  also  smaller,  the  last  often  partially  on 

the  line  of  Involution.  Antisiphonal  lobe 
bifid,  very  long,  and  sometimes  complex. 
One  pair  of  large  dorsal  saddles,  and  one  of 
short,  often  incomplete  lobes.  Anapytchus 
observed  in  several  species. 

There  are  two  types  of  young  in  the  Arieti- 
•  tinae,  which  afterwards  beconie  separated  in 
other  related  groups :  a  broad  depressed  or 
coronate  type  occurs  in  typical  Arietitcs  and 
some  others,  and  the  conipressed  Psiloceran 
type  in  Arnioceras,  etc.  Pseudotropites  shows 
that  Coeloceras  may  have  originated  from 
the  Arietinae  through  persistent  develop- 
ment  of  a  trapezoidal  form  of  young  with 
correlative  changes.  Arietites  Waagen  (Figs. 
1264,  1265). 

Subgenera  :   Vermiceras,  Corojiiceras  {Fig. 
^*'*         *  ^  IIAQ),  Arnioceras,  Discoceras,  Asterocei'as,  &Tid 

Arietites  bisnlcatus  Brug.    Lower  Lias  ;  COte  d'Or         Ovhioceras  Hvatt       Lias 
(after  d'Orbigny).  ^  J       •  ' 


Psiloceras  planorhis  (Sowb.)-  Infra- 
Lias ;  Bebenhausen,  Würtemberg.  Ana- 
ptychus  in  living  Chamber. 


Subfamily  C.     Aegoce ratin ae  Zittel. 

Form  widely  umbilicate.  Whorls  with  lateral  ribs  which  frequently  either  divided 
or  undivided  extend  across  the  keelless  venter.  Under  this  subfamily  are  two  groups 
of  genera,  the  first  being  that  of  Äegoceras  Waagen  which  Hyatt  has  called  the  "  Liparo- 
ceratidae."  In  this  the  volutions  remain  rounded  in  section  and  frequently  retain  a 
primitive  discoidal  aspect.  Costae  almost  entirely  disappear  on  the  venter  of  some 
forms,  but  form  very  large  continuous  folds  in  others.  Sutures  become  excessively 
complex,  saddles  narrow  and  deeply  cut  by  complex  marginals,  and  ventral  lobe  corre- 
sponds,  but  usually  of  about  equal  length  with  the  lateral  lobes.     Antisiphonal  bifid, 


656 


MOLLUSCA 


PHYLUM  VI 


and  resembles  (as  do  also  the  two  dorsal  saddles  and  small  dorsal  lobes)   tliose   of 
tlie  Arietitinae. 


7..S-1  7.,S'"  '"'      !■ 


IL 


Fior  1265. 

Arütites  Hsulcatus  Brug.     Lower  Lias  ;  Würtemburg.     A,  Suture  line  ;  B,  (\  Portion  of  volution  seen  froiu 

the  lateral  and  ventral  aspects. 

Äegoceras  Waagen  (Fig.  1266) 
Hyatt  has  proposed  tlie  following 
snbgenera :  Liparoceras,  Microdero- 
ceras  and  Ändrogynoceras.  Lower  and 
Middle  Lias. 

The  second  group  is  tliat  of  Schlo- 
theimia  Bayle,  called  by  Hyatt  the 
"  Angulatidae."  This  includes  more 
or  less  compressed  and  costated  shells, 
the  costae  sometimes  crossing  the 
venter  in  the  young  or  extreme  age, 
but  usually  interrupted  in  the  adult 
by  a  smooth  and  occasionally  sunken 
median  zone.  Sutures  inclined  apicad 
near  lines  of  involution,  more  com- 
plex  in  outline  than  in  typical  Ärie- 
tites,  and  with  phylliform  marginals 
Ventral  lobe  broader   and  shorter,  with  larger  siphonal 


Fig.  1266. 

•ö  mpricornus  (Schloth.).     Middle  Lias 
Gmünd,  Würteniberg. 


more  like  tliose  of  Psilocen 


CEPHALOPODA 


G57 


saddles  tlian  Arietües,  and  antisiphonal  lobe  bifid,  longer  and  more  coniplex.     First 
pair   of  doi-sal  saddles  large  and  long,  otlier 
dorsal  inflections  variable,  l)ut  generally  more 
niinierous  tlian  in  Arietües. 

Schlotheimia  Bayle  (Fig.  1267);  Waeh- 
neroceras  Hyatt.     Lower  Lias. 

Subfamily  D.     Polymorphinae  Hang. 

Shells  compressed  discoidal,  with  smooth 
young  like  tliose  of  Psüoceras.  Costae  apt 
to  be  inclined  or  slightly  signiöidal,  and 
continuous  across  the  venter.  Tliis  is  crenu- 
lated  in  primitive  forms,  biit  becomes  smooth, 
Channelled  or  keeled  in  specialised  shells. 
The  latter  have  sutures  similar  to  those  of 
Schlotheimia,  biit  less  complex. 

Agassiceras    Hyatt    {Paroniceras    Bonar.  ; 
Gymhites    Neumayr ;    Amm.   glohosum    Opp. ; 
Amm.  miserabile  Quenst.).     Liparoceras  Hyatt  {Ammonites  bechei  Sow.)  ;  Polymorphites 
Sutner  ;  Dumortieria  Hang  ;  Amphiceras  Gemm.     Lias. 


1267. 


Schlotheimia  angulata  (Schloth.).     Lower  Lias  ; 
Göppingen,  Würteniberg. 


Family  22.     Harpoceratidae  Neumayr. 

Discoidal  and  involute  shells,  with  sigmoidal  costae.  Venter  with  smooth  or  crenuloAed 
keel.  Ayerture  with  curved  sides  or  with  projecting  lateral  ears,  and  rounded  ventral 
crest.  Septa  simply  digitale,  ivith  the  lobes  and  saddles  arranged  in  a  straight  line,  and 
usually  with  several  auxiliary  lobes. 

This  family,  which  probably  originated  from  the  Arietitinae,  ranges  from  the 
Lias  to  the  Lower  Cretaceous. 


Subfamily  A.     Harpoce ratin ae  Zittel. 
Discoidal  involute  shells  with  sigmoidal  costae  separated  throughout  or  confluent 


Hildoceras  bifrons  (Brug.)-     Upper  Lias  ; 
Whitby,  Yorkshire. 


Lioceras  opalinnm  (Rein.).     Lower  Dogger  ; 
Teufelsloch,  near  BoU,  Wiirtemberg. 


on  the  median  lateral  line,  and  sometimes  bifurcated  externally.     Nodes  never  präsent, 
VOL.  I  2  U 


658 


MOLLUSCA 


PHYLUM  VI 


although  prominent  crescentic  ridges  may  arise  on  the  sides  tlirough  confluence  of 
costae.     The  latter  are  straiglit  in  i^rimitive  Catulloceras,  wliich  resenibles  Caloceras 

in  aspect.  Discoidal  forms  often  both 
keeled  and  channelled  on  the  venter,  and 
sometimes  have  broad  furrows  on  the 
sides.  Specialised  invohite  shells  have 
solid  keels,  bnt  iisually  no  Channels,  and 
lateral  zones  often  become  smootli.  Sutures 
comparatively  simple,  and  in  discoidal 
forms  are  similar  to  those  of  Ärnioceras, 
biit  more  complex  in  highly  involute 
forms, 

Harpoceras  Waagen,  and  subgenera : 
Hildoceras  (Fig.  1268),  Lioceras  (Fig. 
1269),  Grammoceras  Hyatt  (Fig.  1270); 
Gatulloceras  Gemm. ;  Arietieras  Seg. ; 
Hyperlioceras,  Graphoceras,  Brasilia  and 
Darellia  Buckman.  Upper  Lias  and  In- 
ferior Oolite. 

Poecilomorphus,      Huddlestonia^ 
Brodieia,  Gosmogyria,  Welschia  Buckman  ; 
Ludwigia  Bayle,     These  are  also  subgenera  from  the  Inferior  Oolite. 


Fio.  1270. 

Harpoceras  Grammoceras  thouarsensi  d'Orb.     Upper 
Lias ;  Heiningen,  Würtemberg. 


Subfamily  B.     Oppeliinae  Hang. 

Discoidal  and  highly  involute  shells  with  sutures,  form  and  markings  in  primitive 
species  that  show  affinity  with  Harpoceran  stock,  and  apparent  derivation  from  Poecilo- 
morphus through  typical  Oecotraustes.  Costae  highly  flexed  and  sometimes  fused,  but 
no  well-marked  lateral  Channels  as  in  hollow-keeled  groups.  Venter  often  truncated 
and  sides  flattened,  except  in  primitive  species.  The  keel 
may  become  very  prominent,  and  fiUed  with  shell  layers, 
but  never  hoUow.  It  disappears  on  the  body  Chamber. 
Aperture  with  ventral  crest.  The  sigmoidal  ribs  often  end 
in  marginal  knots.  Septa  finely  digitate.  This  subfamily 
ranges  from  the  Middle  Jura  to  the  Cretaceous,  its  maximum 
falling  in  the  Upper  Jura.  Typical  genera  are  Oppelia 
Waagen  (Figs.  1155,  1157,  and  1158),  and  Oecotraustes 
Waagen  (Fig.  1271).  A  revision  of  the  group  has  recently 
been  published  by  Douville  (1913).  p^^,  ^271. 

Oppelia  has  been  subdivided  into  a  large  number  of  oecotraustes  macrotelns 
groups,  or  transitional  series  ("  Formenreihe  "),  some  of  which  (^ppei).  Tithonian  ;  stram- 
might  even  take  rank  as  subfamilies,  but  most  of  them  ^^^' 
are  hardly  more  than  subgenera.  The  largest  group,  which  Hyatt  distinguished 
under  the  name  "  Glochiceratidae,"  includes  discoidal  and  involute 
Shells,  smooth  in  primitive  species,  but  acquiring  highly  inflected 
costations,  sometimes  with  two  rows  of  tubercles  on  the  sides,  and 
a  median  ventral  row  that  may  fuse  into  a  continuous  solid  keel. 
One  line  of  ventral  tubercles  may  also  arise  directly  from  folds  that 
appear  in  otherwise  unornamented  shells.  Aperture  sometimes 
with  long  lateral  lappets.  Sutures  similar  to  those  in  the  Haplo- 
ceratidae. 

Gadomoceras,  Creiiiceras,  Mun.-Chalm.  (Fig.  1272);  Phlycticeras 
{Lophoceras    Bonar.) ;    Ochetoceras    Hang    (Fig.    1273);    Gy  macer  as 
Quenst.  (emend.  Hyatt).     Type  G.  (Ammonites)  guemheli  (Opp.).     Strigoceras  Quenst. 


Fig.  1272. 
Creniceraa    renggcri 
(Oppel).      Oxford  i  an  ; 
Salins,  Jura. 


CLASS  V 


CEPHALOPODA 


659 


(Buckman);    StrehUtes    Hyatt    (Fig.    1274).       Type   S.    (Ämmonites)  iiidus-costatus 
(Quenst.).     Glochiceras  Hyatt.     Middle  and  Upper  Jura. 

Another  group,  which   Hyatt   called    "  Distichioceratidae,"  includes    the   genera 


1273. 


Ochetoceras  flexuosum  (v.  Buch).     Upper 
Jura  (jS) ;  Laufen,  Würtemberg. 


Fig.  1274. 

StreUites  tenuilöbatus  (Oppel).    Upper  Jura 

Pappenheim,  Bavaria. 


Horioceras  and  Distichoceras  Munier-Chalmas,  witli  septa  simpler  than  in  GlochiceraS) 
owing  to  arrested  development.  The  yoimg  of  Distichoceras  repeat  the  characteristic 
form  and  costae  of  Glochiceras^  with  smooth  venter  and  lateral  tubercles  and  then 
acqiiire  the  featiires  of  Horioceras  before  the 
median  continuoiis  keel  of  Distichoceras  arises. 


Family  23.     Amaltheidae  Fischer  (pars). 

Form  laterally  compressed,  usnally  involute, 
high  whorled.  Sides  with  gently  curved  ribs  or 
folds,  and  often  with  lateral  knots  or  spiral 
lines.  Venter  keeled,  and  the  keel  is  often 
crenulated  by  ribs  or  thickened  growth  lines. 
Aperture  simple,  or  with  narrow  ventral  crest. 
Sutures  deeply  digitate  with  several  auxiliary 
lobes. 

Subfamily  A.     Amaltheinäe  Hyatt. 

Discoidal  and  involute  shells,  the  young  of 
which  have  fold-like  costae  rising  into  heavy 
nodes  just  inside  the  lines  of  involution.  Costae 
became  prominent  and   sharp  at   the  umbilical 


Pio.  127 


AmaWieus    margaritatus    Montf.       Middle 
■Uli  1  j.        1    i.       1  1  j     4.  ^'*^ '  Würtemberg.     Living  Chamber  broken 

Shoulders  and  ventro- lateral  angles,  and  true  away  and  exposing  "  wrinkied  layer "  on 
tubercles  appear  in  some  groups.     Venter  keeled   IT^^^}  f"^^^?,"-,  V^^^Jl^  homoiogous  witii  the 

T        11  ,  11^  Till  olack  layer    of  Nautilus. 

and  sulcated  m  discoidal  forms,  the  keels  alone 

persisting  in  more  involute  species.  Keel  solid  and  crenulated  by  the  passage  of  costae 
or  folds  across  the  venter.  Anaptychus  present.  Nodes  prominent  in  the  young  of 
primitive  species ;  costae  with  only  one  row  of  tubercles  in  later  stages  or  none  ;  keel 
invariably  present  and  crenulated.  Amaltheus  Montf.  (Figs.  1 150  ;  1160,  ^  ;  1275) ; 
Paltopleuroceras  Buckm.  {Pleuroceras  Hyatt).     Middle  Lias. 


660 


MOLLUSCA 


PHYLÜM  VI 


In  another  group  of  tlie  Amaltlieinae,  tlie  yonng  usually  have  gibbous  volutions  witli 
a  Single  row  of  nodes,  wliich  eitlier  persist,  or  are  followed  by  a  bispinous  stage,  and 

inner  ends  of  tlie  sliort  costae  also  become 
tuberculated.  Venter  smootli  at  first,  and 
niay  remain  so  or  may  have  a  solid  keel. 
Costae  Single,  and  usually  bend  at  ventro- 
lateral  angles  toward  the  keel,  but  do  not 
cross  the  venter  except  in  late  stage  of 
Pseudotropites.  Haplopleuroceras  and 
Borsetensia  Buckm. ;  Pseudotropites 
Canav. ;  Ganavarites  Hyatt.  Type  C. 
(Ärietites)  discretum  (Canav.).  Lias  to 
Inferior  Oolite. 

The  Amaltheinae  are  usually  classed 
as  derivatives  from  the  Arietitinae,  but 
this  is  doubtful.  Oxynoticeras  Hyatt 
(Fig.  1276)  from  the  Lias,  is  classed  by 
most  writers  with  the  Amaltheidae, 
although  Hyatt  regarded  it  as  a  member 
of  the  Arietitinae.  In  this  genus  the 
Shells  are  compressed  and  more  involute  than  in  the  Arietidae,  with  narrower  and 
more  acute  keeled  venter,  but  no  ventral  Channels.  Sutures  have  extended  and 
highly  modified  auxiliary  inflections  ;  keel  hollow  in  adult  of  some  species.    Lower  Lias. 


Fio.  1276. 

OxynoHce.ras  oxynotum  (Quenst.). 
(ß) ;  Würtemberg. 


Lower  Lias. 


Subfamily  B.     Hammatoceratinae  Buckman. 

Discoidal  forms  with  Single  or  bifurcated  costae,  keeled  and  often  channelled 
Young  similar  to  those  of  the  Harpo- 
ceratinae    in  compressed   forms.     Keel 
hollow. 

Cycloceras  and  Hammatoceras  Hyatt ; 
Lillia  Bayle ;  Haugia^  Polyplectus,  Chart- 
ronia,  Benchmannia  Buckm. ;  Zurcheria 
Douville. 

Upper  Lias  and  Inferior  Oolite. 

The  Hammatoceratinae  have  usually 
been  classed  as  near  relatives  of  the 
Arietitinae  but  their  systematic  position 
should  probably  be  in  the  Amaltheidae, 
with  which  they  sliow  near  affinities  in 
form  and  septation. 

Buckman  placed  two  genera  or  sub- 
genera  of  this  subfamily  in  a  separate 
group  "  Sonniniinae."  Sonninia  includes 
discoidal  forms  with  a  keeled  but  not 
Channelled  venter,  and  sides  with  coarse 
bifurcated*  costae  diverging  from  a  row 
of  nodes  along  the  median  line  of  the 
rounded  sides  and  continued  internally 
by  Single  costae.  WitchelUa  has  nodes 
only  in  the  young,  and  costae  become 
Single  or  only  slightly  confluent.  Sonninia  Bayle  {Waagenia  Bayle)  (Fig, 
WitchelUa  Buckman.     Inferior  Oolite. 


venters. 


1277. 


Sonninia  sowerhyi  (Miller).    Middle  Dogger 
(after  Steinmann  and  Döderlein). 


Lorraine 


1277); 


CLASS  V 


CEPHALOPODA 


661 


Family  24.     Haploceratidae  Zittel. 

Shell  smooth,  with  fine  fjrowth  lines,  ivühout  constrictions.      Venter  rounded,  vnthout 
Jceel.     Apertures  with  lateral  ears  or  lappets.     Septa  deeply  digitale. 

This  family  is  supposed  to  be  an  off-shoot  from  the  Harpoceratidae,  and  nearly 
related  to  Oppelia. 

Haploceras  Zittel 
(Lissoceras  Bayle)  (Fig. 
1278).  From  Middle  Jura 
to  Lower  Cretaceous. 


Family  25.     Stephano- 
ceratidae  Neiimayr. 

Forms  usually  robust 
and  inclined  to  be  coronate, 
at  least  in  youth.  Surface 
with  bifurcating  ribs  that 
extend  across  the  rounded 
venter.  Aperture  with 
lateral  ears  or  lappets^ 
and  usually  constricted. 
Septa  deeply  digitate,  with 
tivo  lateral  lobes  and  two 
or  three  auxiliaries.  Keel 
present  in  some  genera. 

The  Stephanocera- 
tidae  were  derived  from  the 


Fi(i.  127!t. 

.1,  Coelm-eran  suharinalum  (Youiig). 
Whitby,  Yorkshir«.  B,  Suture-liiie  of 
Coeloceras  pettos  Quenst.     Middle  Lias. 


Fig.  1278. 
Haploceras  eUmatum  (Oppel).    Tithonian  ;  Strainberg,  Moravia. 

Aegoceratidae  of  the  Lias,  and  in  turn  gave  rise  to 
most  of  the  Ammonite  families  of  the  later  Jurassic 
and  Cretaceous,  so  much  so  that  it  might  be  well  to 
include  these  and  their  descendants  in  a  superfamily, 
or  suborder  Stephanoceratoidea. 

The  group  has  been  subdivided  into  numerous  so- 
called  families,  most  of  which,  in  so  far  as  they  are 
deserving  of  recognition  at  all,  are  here  treated  as 
subfamilies,  for  the  sake  of  uniformity  in  Classifica- 
tion. It  is  not  meant  to  imply  by  this  that  they 
all  have  equal  taxonomic  rank. 

Subfamily  A.     Dactylioceratinae  Hyatt. 

Discoidal  forms  with  costae  bifurcated  and  always 
Crossing  the  venter.  Sutures  with  very  complex 
outlines,  but  only  three  or  four  pairs  of  lateral  lobes 
and  saddles.  Dorsal  sutures  have  two  pairs  of  saddles 
and  one  pair  of  zygous  lobes, 

This  series  is  usually  termed  the  Plaiiulati  of  the 
Lias,  but  althoiigh  an  ofFslioot  of  the  sarae  common  stock, 
it  is  quite  distinct  from  its  supjiosed  congeners  of  the 
Middle  and  Upper  Jura.  Sutures  are  straight,  not  in- 
clined apicad  as  in  Perisphiuctinae.  The  subfamily  com- 
prises  a  complete  cycle  of  forms  varying  from  the  broad 
trapezoidal,  tuberciilated  volutions  of  Coeloceras  through 
Ariuatoid  species  to  Dactylioceras,  in  which  the  costae 
are  smooth  and  sometimes  even  single. 


662 


MOLLUSCA 


PHYLÜM  VI 


Goeloceras  (Deroceras  Hyatt)  (Fig.  1279),  Dadylioceras  (Fig.  1280)  and  Peronoceras 

Hyatt ;  Pimelites  and  Diafliorites  Fucini ; 
(?)  Praesphaeroceras  Levi ;  (?)  Gollina  Buckm. 
Middle  and  Upper  Lias. 


Subfamily  B.     Stephanoceratinae 
Steinmann. 


Fi(i.  1280. 

Dactylioceras  commune  (Sovvb.).     Upper  Lias 
England. 


Primitive  radicals,  highly  coronate,  dis- 
coidal,  giving  rise  ai)parently  to  involute  and 
partially  comjiressed  forms  that  in  Macro- 
cephalites  and  some  otliers  are  without  tubercles, 
Venter  always  rounded,  costae  bifnrcating  on 
the  sides  and  continuous  acroßs  tlie  venter. 
Only  one  line  of  nodes  or  tubercles  at  tlie 
umbilical  Shoulders,  and  the  division  of  costae 


Fig.  1281. 

SpJuxerocerasbrongniarti  (Sowb.).     Inferior 
Oolite ;  Bayeux,  Calvados. 


Fk;.  1282. 

Normannitcs  braikenridgei  (Sowb.).     In- 
ferior Oolite  ;  Bayeux,  Calvados,    i/i. 


takes  place  along  these  lines  in  most  forms.     Sutures  of  the  same  type  as  in  Dacty- 


Fic.  V2S3. 


Af«r»e„A„«,»  M^r„o,p„a,u.  (Scl.lotl,.,.     Upp»  Doggor  (Callovian) ;  Ehninge,,,  Würtcmbsrg. 

lioidmae,  l.ut  nnich  more  complex,  with  usually  „lore  iniiections,  and  lote  and  saddle. 


J 


CLAS8  V 


CEPHALOPODA 


663 


iiiore  nearly  equal.      Doi-sal  sutures  generally  have  three  pairs  of  zygoiis  saddles  and 

two  pairs  of  lobes  in  tlie  coronate  discoidal 

forms. 

Stefhanoceras  Neiim.  (Fig.  1285);  Gado- 
mites  Mim.-Chalnis.  ;  S2)haeroceras  Bayle  (Fig. 
1281);  Emiida  Buckman ;  Normannites 
Miin.-Clialmas  (Fig.  1282);  Macrocephalites 
Sutner  (Fig.  1283);  Sutnerm  Zittel  (Fig.  1284). 
Inferior  Oolite. 


Sutneria  platynota  (Rein.).  Upper 
Jura  (Tenuilobatus  Beds) ;  Balingen, 
Wärtern  barg. 


Fig.  1l>85. 

StepTiiiTUKeras  cor(ynati(s  (Brug.).     Callovian 

Dept.  Nievre,  France.    1/3- 


Subfamily  C.     Cadoceratinae  Hyatt. 

More  specialised,  comjDressed,  and  involute  forms  tend  to  evolve  shells  with 
crenulated  keels,  and  sometimes  Channels  also.  Costae  of  Gadoceras  divided  as  in 
Steplianoceratinae,  but  other  genera  usually  develop  two  lines  of  tubercles.  Young 
of  Neumayria  more  or  less  costated,  but  sides  and  keel  become  smooth,  and  in  some 
species  resemble  the  adult  of  Quenstedtoceras. 

Tills  group  is  remarkable  for  the  close  parallelism  of  some  of  its  genera  with  Amaltheidae, 
but  the  young  are  very  distinct.  Development  and  adul  t  stages  of  Gadoceras  with  its  discoidal 
and  much  depressed  volutions  plainly  show  derivation  from  Coeloceran  stock,  while  its  form 
and  sutures  also  show  relationsliip  with  Steplianoceratinae. 

Gadoceras  Fischer ;  Quenstedtoceras  Hyatt ;  Gardioceras  Neumayr  and  Uhlig ; 
Neumayria  Nikitin.     Kelloway. 


Subfamily  D.     Perisphinctinae  Steinmann.^ 

An  extensive  series  of  discoidal  genera  having  rounded  or  subquadrangular 
volutions,  and  costae  single  on  the  sides,  but  split  into  two,  three  or  more  on  the 
venter,  which  they  cross  uninterruptedly.  Splitting  does  not  begin  as  a  rule  at 
umbilical  Shoulders,  but  near  the  ventro-lateral  angles.  Inner  parts  of  sutures  steeply 
inclined  apicad,  and  dorsal  sutures  have  a  long  pair  of  first  dorsal  saddles,  usually  two 
additional  pairs  of  saddles,  and  two  pairs  of  lobes.  All  of  these  are  so  decidedly 
inclined  apicad  that  they  often  appear  as  a  single  pair  of  complex  saddles. 

These  genera  are  morphic  equivalents  of  the  Liassic  Dactylioidinae  and  are  derived  from 
the  same  common  stock.  Young  have  depressed  trapezoidal  volutions  and  often  minute 
tubercles  on  ventro-lateral  angles,  but  are  otherwise  smooth,  like  the  young  of  Gadoceras 
sublaeve.  They  become  compressed  in  the  neanic  stage  and  rapidly  assiime  the  discoidal 
Perisphinctean  form  and  costae  without  tubercles. 

Perisphinctes  Waagen    {Grossüuvria,   ProceriteSy  Ghoffatia  Siemirad.)  (Figs.   1286- 

^  Sieviiradzki,  ./.,  Monographische  Beschreibung  der  Gattung  Perisphinctes.  Palaeontogr.  1898, 
vol.  xlv.     See  also  R.  DouvilU's  recent  studies  of  Gardioceras,  etc.,  1913. 


664  MOLLUSCA 

1288) ;  Ätaxioceras  Font.;  FroplamiUtes  Teiss.;  Pidonia  Bayle  ; 
Lampl.     Inferior  Oolite  and  Cretaceous. 


PHYLUM  VI 


Pavl.  and 


FiCr.  1286, 

Suture  line  of  Perisphindes  colubrinus 

(Rein.). 


Fi(i.  1287. 

Perisphinctes polyplocus  (Rein.).    Upper 
Jura ;  Pappenheim,  Bavaria.    i/g. 


Perisphinctes  tiziani  (Oppel).     Upper  Jura  (Bimammatus  Beds) ; 
Hundsrück,  near  Streichen,  Würtemberg. 


Subfamily  E.     Morphoce  ratin ae  Hyatt. 

Globose  and  iisually  involute  fornis  witli  open  umbilici  showing  the  yoimg  to  be 
highly  coronate  imtil  a  late  stage.     Costae  on   iimbilical   zones  Single  and  widely 

separated,  but  divided  into 
very  broad  biindles  of  fine, 
closely  -  set,  ventro  -  lateral 
costae  diflering  from  those  of 
all  other  groups  except  sonie 
Perisphinctinae.  Only  one 
line  of  tubercles  or  nodes, 
whicli  usually  occiir  at  um- 
bilical  Shoulders.  External 
and  dorsal  sutures  resemble 
those  of  Perisphinctinae,  but 
not  so  imiformly  inclined 
apicad.  In  discoidal  coronate 
Shells  the  lobes  and  saddles 
are  of  equal  length,  and 
dorsum  has  two  pairs  of 
zygous  lobes  and  two  pairs  of 
saddles. 

Morphoceras  Douv. ; 
Garantiana  Siemirad.  ;  Olco- 
stephanus  Neuni.  {Holcostephanus  aiict.) ;  Folyptijchites,  SimhirsJdtes,  Ästieria,  and 
Virgatites  Pavl.  and  Lampl.      Upper  Jura  and  Cretaceous. 


Fi(i.  1289. 
ReinerJcia  hrancoia  (Steinm.).     Caracoles,  Boliva  (after  Steiiimann). 


CLASS  V 


CEPHALOPODA 


665 


Siibfaiiiily  F.     Reineckiinae  Hyatt. 

Discoidal  shells  with  costae  siiigle  on  the  lateral  zones  but  bifuicated  on  their 
outer  parts,  and 
with  one  or  two 
liiies  of  tubercles, 
the  first  being 
iiear  the  point  of 
bifurcatioii  of  the 
costae,  and  the 
other  near  their 
ventral  termini. 
Division  of  costae 
takes  place  along 
ventro -  lateral 
angles  and  not  on 
or  near  the  um- 
bilical  Shoulders. 
Costae  cross  the 
venter  only  in 
the  coronate 
young,  when  the 
section  is  trape- 
zoidal  as  in  Goeloceras.     Sutures  as  in  the  preceding  subfamily. 

Reineckia  (Fig.  1289),  Parkinsonia  Bayle  (Fig.  1290);  Oecoptychius  Neum.  (Fig. 
1291);  Äulacostephanus  Sutner  and  Pomp;  (?)  Waagenia  Neum.;  Strenoceras  Hyatt. 
Type  *S^.  (Ammonites)  niortense  (d'Orb.).     Middle  and  Upper  Jura. 


Fio.  1290. 

Farkinsonia  farkinsoni  (Sowb.).     Inferior  Oolite  ; 
Bayeux,  Calvados. 


Fig.  1291. 

Oecoptychius  refractus 
(de  Haan).  Callovian  ; 
Niort,  France  (after 
d'Orbigny). 


Family  26.     Aspidoceratidae  Zittel. 

Earlier  volutions  costate,  later  ones  with  one  or  two  rows  of  tubercles.      Venter  hroad, 
never  keeled.    Septa  resemhling  those  of  Dactylioidinae,  hut  saddles  omd  lohes  hroader^  and 


Fig.  1292. 

Aspidoceras  2iemrmatum  (Sowb.).    Oxfordian 

Dives,  Calvados.     V'2- 


Fi«;.  1293. 

Simocfnu^  volanense  (Oppel). 
Lower  Titlionian  ;  Monte  Catria, 
Central  Apennines. 


dorsal  sutures  loith  only  one  large  pair  of  inner  or  first  dorsal  lobes^  the  outer  or  second 
pair  being  incomplete  in  the  more  discoidal  species  as  in  the  Arietidae. 

Aspidoceras   Zittel  (Fig.    1292);    Peltoceras   Waagen   (Fig.    1294);    (?)  Aurigcrus 


PHYLUM  VI 


QQQ  MOLLUSCA 

Oprel;  (?)  Simoceras  Zittel  (Fig.  1293);  Siemiradzkia  Hyatt.       Type  S.  (Ämmonites) 


Fio.  1294. 


Peltoceras  athleta  (Phill.).     Upper  Callovian  ;  Vaches  noires, 
Normandy.     i/i. 


riiysodoceras  circum- 
spinosum  (Oppel).  Upper 
Jura ;  Swabian  Alps.    1/2. 


bakeriae  (d'Orb.)  [Terr.  Jurass.  PL  149,  Fig.  1,  non  PL   148].      Physodoceras  Hyatt 
(Fig.  1295).     Type  P.  (Ämmonites)  circumspinosum  (Oppel).     Upper  Jura. 


Family  27.     Desmoceratidae  ZitteL 


Discoidal  moderately  involute  forms,  with  simple  or  divided  rihs.  These  continue 
without  Interruption  across  the  rounded  keelless  venter.  Gonstrictions  or  varices  at 
regulär  intervals.     Septa  finely  digitate,  with  auxiliary  lohes  arranged  in  a  straight  row. 

The  Desmoceratidae  are  slightly  modified  descendants  of  the  Stephanoceratidae, 
and  preserve  in  youth  the  characters  of  the  ancestral  family. 


Subfamily  A.     Desmoceratinae  Zittel  (pars). 

Mostly  involute  shells,  smooth,  or  with  constrictions  and  fold-like  costae  without 

tubercles  that  commonly  follow  the 
lines  of  growth  across  the  rounded 
venter  uninterruptedly.  Spines 
sometimes  present  as  in  preceding 
family.  Sutures  have  blunt 
siphonal  saddles,  never  pointed. 
First  lateral  lobes  shallower  than 
Fio.  1296.  "^    ^^^    Lytoceratidae,     the    first 

lateral  saddles  broader,  and  less 
deeply  cut  by  marginals.  Anti- 
siphonal  lobe  long,   straight,  and 

trifid.     Lateral  zygous  inflections  more  numerous,  and  there  are  often  three  or  more 

zygous  dorsal  saddles. 


Suture-line  of  Desmoceras  latidorsatum  Mich.    Gault : 
Parte  du  Rhone. 


CLASS  V 


CEPHALOPODA 


667 


Eurynoticeras  Canavari. 


Jura.  Desmoceras  Zittel  (Figs.  1296,  1297);  Puzosia 
Bayle ;  Gleonoceras  Paroiii  and 
Bon.  ;  Schlueteria,  Hauericeras 
Grossouvre.     Cretaceous. 


Subfamüy  B.     Silesitinae 
Hyatt. 

Similar  to  the  Desmoceratinae, 
but  costae  more  strongly  de- 
veloped,  and  sometimes  spinous. 


Fio.  1297. 

Desmoceras  inayorianum  (d'Orb.).     Gault ;  Perte  du  Rhone 
(after  d'Orbigiiy). 


Fio.  15 
Fachydiscus  feramplus  (Mantell).     Lower  Chalk  ;  England. 


Fig.  1299. 

Pcichydiscus  wittekindi  (Schlüter). 
Upper  Cretaceous  ;  Haldem,  West- 
phalia.    1/3. 


Süesites,  Holcodiscus  Uhlig ;  Fachydiscus  Zittel  (Figs.   1298,   1299);  Parapachy- 
discus  Hyatt.     Type  P.  {Ammonites)  gollevülensis  (d'Orb.).     Cretaceous. 


Family  28.     Oosmoceratidae  Zittel. 

Shells  richly  ornamented  with  ribs  that  are  divided,  or  broken  wp  into  rows  of  hnots. 
Usually  with  rows  of  umbilical  and  marginal  hnots  on  the  ribs.  Sculpture  interrupted 
by  a  furrow  on  the  venter.  Aperture  often  with  lateral  ears  or  lappets.  ?  Septa  deeply 
digitate.      One  or  two  auxiliary  lobes  present. 


668 


MOLLUSCA 


PHYLÜM  Vll 


The  Cosmoceratidae  are    probably   a    polyphyletic    group,  derived    from  severalj 
branclies  of  tlie  Steplianoceratidae. 


Subfamily  A.     Cosmocbratinae  Hyatt. 

Discoidal  and  involute  forms  having  at  a  comparatively  early  stage  or  throughout 

life  two  or  tbree  rows  of  large  tubercles 
■■^^  nf^7J?j)»«a  Qj^  gg^(3i-^  gi(je^  and  costae  interrupted  on 

the  venter  by  a  sniooth  median  zone  or 
Channel. 

Gosmoceras      Waagen      (Fig.      1300). 
Middle  Lias  to  Oxfordian. 


Subfamily  B.     Hoplitinae  Hyatt. 

Discoidal    and    involute    forms    with 
costae  bifurcated  on  the  sides  at  umbilical 


Fio.  1300. 

Gosmoceras  ornatum  (Sowb.).     Callovian  (Ornaten 
thon) ;  Gamiuelsliausen,  Würteniberg. 


Fit;.  1301 


Hoplites  tuberculatus  (Sowb.). 
Gault ;  Folkestone,  England 
Siphuncle  broken  away  f 


Fig.  1302. 

Uoplites  noricus  (Sowb.).     i  =  Ho2Mtes  amUygonius  Neum,).     Neocoraian  ; 

Achim,  near  Börsuni,  Prussia. 


Shoulders ;  prominent  tubercles  at  their  forks,  and  also  at  or  near  their  ventral 
termini,  these  last  being  separated  by  a  median  zone  or  deep  Channel.  Young  of 
some  species  have  costae  continuous  across  the  venter,  and  resemble  those  of  Sonneratia. 
Parallelism  with  Cosmoceratinae  very  close.  Sutures  resemble  those  of  Mammites, 
but  more  complex.  Lateral  saddles  narrower  and  more  deeply  cut,  and  first  lateral 
saddles  often  trifid  in  late  stages.  Dorsal  series  with  two  pairs  of  complex  zygous 
lobes  and  saddles  on  either  side  of  a  long,  narrow,  complex,  antisiphonal  lobe. 

Hoplites  Neum.  (Figs.    1301,    1302);   Genomanites  Hang    {Discoceras   Kossmat) ; 
Sonneratia  Bayle  ;  Neocomites  Uhlig.      Cretaceous. 


CLASS  V 


CEPHALOPODA 


669 


Subfamily  C.     Acanthoceratinae  Hyatt. 

Robust    and    nioderately  evolute  forma.     Surface  highly  ornamented  witli   ribs 
either  simple  or  bifurcating.     Rows  of  tubercles  usiially  present  on  ribs,  and  often  a 


Fi(i.  1303. 
Acanthoceras  rhototnagense  (Defr.).     Cenomanian  ;  Rouen,  France  (after  Quenstedt). 


Fio.  1304. 
Douvilleweras  mamiUarc  (Schloth.).     Gault ;  Macherom^nil,  Ardennes. 

median  row,  sometimes  uniting  in  a  keel.     Septa  deeply  digitale,  the  first  lateral 
saddle  being  bifid. 

Acanthoceras  Neiimayr  (Fig.  1303);  Douvüleiceras  Gross.  (Fig.  1304);  ITiur- 
mannia  Hyatt ;  Steueroceras  Cossmann  {Odontoceras  Steuer) ;  Mammites  Laube  and 
Bruder  :  Muniericeras  and  Barroisiceras  Gross.     Cretaceous. 


Subfamily  D.     Crioceratinae  Hyatt. 

A  heterogeneous  group  of  degenerate  forms,  probably  derived  from  several  different 
normal  groups.     Forms   higbly   ornamented  witli.  ribs  and   spines  or   knota.     The 


670 


MOLLUSCA 


PHYLUM  VI 


youtliful  whorls  are  coiled  spirally  in  a  plane ;  at  maturity  the  whorl  straightens  out 
temporarily,  often  bending  back  again  in  a  hook-sliaped  body -Chamber. 


Fig.  13G5. 


Spiroceras  bifurcatum  (Quenst.).  Upper  Dogger  (Cal- 
lovian) ;  Ehningen,  Würtemberg.  A,  Shell  with  protoconch 
broken  away,  i/j.    B,  Portion  of  venter.     (',  Suture-line. 


Fio.  1306. 


Ancyloceras  matheronianum  d'Orb.  Neocomian  ; 
Castellane,  Basses  Alpes.  A,  Concli.  U,  Suture- 
line. 


Spiroceras  Quenstedt  (Fig.   1305),  Lower   Oolite,   supposed    to    be  derived    from 
Parkinsonia.     Grioceras  Leveille  ;  ^.wc^Zoceras  d'Orb.  (Fig.  1306).     Cretaceous. 


Subfamily  E.     Scaphitinae  Meek. 

Whorl  close-coiled  in  youth,  opening  out  at 
maturity  into  a  hook- 
shaped  body  -  Chamber. 
Form  robust,  tliick-set, 
involute,  surface  highly 
ornamental  with  ribs 
and  knots.  Septa  finely 
digitate,  usually  with 
several  auxiliary  lobes. 

Scaphites    Parkinson 
(Figs.  1162, 1307,  1308); 
Fin.  1308.  Discoscaphites        Meek ; 

rfZnÄn,-"''^''''^'T,  ^°'^^-    Jahnites  Hyatt.      Greta- 

i^enonianian;     Ronen  ^ 

France,     l/i-  ceoUS. 


Fir„  1307. 

Scaphites  spiniger  Schlüter.     Upper  Greta 
ceous  (Senonian) ;  Coesfeld,  Westphalia. 


CLASS  V 


CEPHALOPODA 


671 


Subfamily  F.     Placentice ratin ae  Hyatt. 

Coiupressed,  involute,  higli-whorled  forms,  witli  venters  flat  coinijressed  or  concave 
in  youth,  becoming  somewhat  rounded  witli  age.  Surface  either  tuberculate  or 
smooth.  Septa  complex,  with 
irregulär  outlines,  and  narrow 
saddles. 

This  group  appears  to  be  little 
modified  from  the  ancestral  Cosmo- 
ceratinae,!  and  of  all  tlie  so-called 
Pseudoceratites  of  the  Cretaceous  it 
is  nearest  to  the  typical  form. 

FlacenHcerasM.Qek  ;  JDvplacomo- 
ceras  Hyatt ;  Forbesiceras  Kossmat. 
Cretaceous. 


Family  29. 


Bngonoceratidae 
Hyatt. 


Indoceras  ismaeli  (Zittel).     Upper  Seiionian  ;  Libyan 
Desert  west  of  Oasis  Dachsei. 


Shell  compressed,  patelliform, 
narrowly  uvihilicate,  high  lohorled. 
Venter  ßattened  or  rounded,  or 
acute.  Flanks  with  broad  low  folds 
which  often  end  in  marginal  keels, 
more    seldom    in     knots    or    spines. 

Septa  not  deeply  digitate,  lobes  usually  only  moderately  serrated,  saddles  often  rounded 
and  entire.  The  external  saddle  is  often  divided  into  several  secondary  lobes.  There 
are  several  auxiliary  lobes  in  most  genera. 

The   Engonoceratidae    were  probably  derived    from    the    Placenticeratinae,   and 

through  them  from  the  Cosmoceratinae. 

Engonoceras  Neumayr ;  Metengonoceras 
Hyatt ;  Hoplitoides  von  Koenen ;  Indoceras 
Noetling  (Fig.  1309);  Sphenodiscus  Meek. 
Cretaceous. 


Family  30.     Pulchelliidae  Douville. 

Form  involute  and  high  whorled.  Venter 
ßattened  or  rounded  or  acute.  Flanks  smooth, 
or  ornamented  loith  ribs  or  knots.  Septa  not 
digitate,  being  mostly  either  ceratitic  or  gonia- 
titic  in  character.  Lobes  and  saddles  shcdlow, 
löith  broad  saddles  and  narrow  lobes.  External 
saddle  divided  into  several  secondary  lobes. 
Auxiliary  lobes  two  to  three  in  number. 

The  Pulchelliidae  were  probably  derived 
from  the  Hojilitinae.  Pulchellia  Douville ; 
Metoicoceras  Hyatt ;  Knemiceras  J.  Boehm  ; 
Buchiceras  Hyatt ;  lloemeroceras  Hyatt ;  Tissotia 
Douville  (Fig.  1310).     Cretaceous. 


Vir..  1310. 

Tissotia  fourndi  Bayle.     Cenomanian  ;  Mzabel- 
M'sai,  Algiers  (after  Bayle). 


^  Smith,  J.  P.,  The  developmeiit  and   i)liylogeiiy  of  Placenticeras. 
Sei.,  3rd  ser.,  Geol.,  1900,  vol.  1.  No.  7. 


Proc.  California  Acad. 


672 


MOLLUSCA 


PHYLUM  VI 


In  this  familyi  probably  beloiig  several  geiiera  comnionly  classed  witli  Oxynoticeras 
or  Amaltheus,  as  follows  :— Garnieria  Sayii.  ;  Lenticeras  Gehr.  ;  Eulophoceras  Hyatt. 

Family  3L     Prionotropidae  Zittel. 
Form    evolute.    discoidal,    laterally    compressed.      Flanhs   with    strong,    simple   or 
dichotomous  ribs   that  form  one  or  more  rows  of  hnots  on  the  sides,  and  one  on   the 
ventral  Shoulders.      Venter  with  sträng  median  keel,  either  smooth  or  hrolen  up  mto  a 


Fi(!.  1311. 

Schloenbadda  varians  (Sowb,)-    Cenomanian 
Quedlinburg,  Saxony. 


Fig.  1312. 

SchloenbacMa  cristata  (Deluc), 
Lower  Cretaceous. 


roiv  of  hnots.  Septa  only  moderately  digitate.  External  and  first  lateral  saddle  hroad, 
lateral  lohes  hifid,  only  one  auxiliary  lohe  present. 

This  groiip  is  commonly  siipposed  to  have  been  derived  from  the  Amaltheidae, 
but  proofs  of  the  connection  are  lacking. 

SchloenbacMa  Neumayr  (Figs.  1311,  1312);  Hystatoceras  Hyatt;  Barroisiceras 
Gross. ;  Mortoniceras  Meek  ;  Peroniceras  Gross. ;  Prionotropis  Meek.     Cretaceous. 


Range   and   Distribution   of  the   Ammonoidea. 

The  Ammonoids  are  more  than  twice  as  rieh  in  forms  as  the  Nautiloids.  While 
of  the  latter  aboiit  2500  species  have  been  described,  the  number  of  Ammonoids  has 
reached  far  beyond  5000  species.  These  are  without  exception  extinct,  and  are 
especially  characteristic  of  the  Mesozoic  era. 

Although  Ammonites  are  unknown  later  than  the  Cretaceous  period,  nevertheless 
this  group  must  be  regarded  on  the  whole  as  the  younger  brauch  of  the  stock  of 
Tetrabranchiates.  After  the  Nautiloids  had  passed  their  culmination,  the  Goniatites 
and  Clymenias  appeared  as  the  oldest  representatives  of  the  Ammonoids.  The  time 
ränge  of  the  Clymenias  is  limited  to  a  short  epoch  in  the  Upper  Devonian  ;  the 
Goniatites  appeared  first  in  the  Upper  Silurian  (Kellerwald),  developed  a  great 
variety  of  forms  in  the  Devonian,  and  continue  until  the  close  of  the  Paleozoic  era. 

Until  a  few  years  ago  it  was  belle ved  that  only  Goniatites  and  Clymenias  occurred 
in  the  Paleozoic  deposits.  The  discovery  of  genuine  Ammonites  in  the  Permian  of 
the  Salt  Range  of  India,  in  the  Ural  Mountains,  in  Texas,  in  the  Fusulina  limestone 
of  Sicily,  etc.,  and  later  the  discovery  of  primitive  Ammonites  in  the  Goal  Measures 
of  Texas  and  in  the  Lower  Carboniferous  of  the  Mississippi  Valley,  piished  their  ränge 

^  DonvilU,  IL,  Evolution  et  Classification  des  Pulchellides.    Bull.  See.  Geol.  France,  1911,  vol.  xi. 


CLASS  V  RANGE  OF  THE  AMMONOIDEA  673 

consideraLly  furtlier  back  into  the  Caiboniferous  system.  These  Paleozoic  Aiunionoids 
stand  in  the  development  of  their  septa  between  the  Goniatites  and  the  more  highly 
ypecialised  Mesozoic  Ammonites. 

With  the  beginning  of  tlie  Mesozoic  era,  the  triie  Ammonites  developed  with 
great  rapidity.  In  the  middlo  European  Muschelkalk  only  the  genera  Ceratites, 
JienecJceia,  Hungarites,  Balatoni^es,  Arniotites^  Acrochordiceras  and  Ptychites  have  as 
yet  been  discovered.  On  the  oilier  hand,  in  the  Alps,  Spitzbergen,  the  Himalayas, 
in  western  North  America  and 'in  Siberia,  there  have  been  found  great  numbers  of 
Ammonites  in  rieh  faunas  of  the  Lower,  Middle  and  Upper  Triassic.  The  families 
of  Tropitidae,  Ceratitidae,  Ptychitidae,  Cladiscitidae  and  Pinacoceratidae  belong 
exclusively  to  the  Triassic ;  the  Arcestidae  begin  in  the  Goal  Measures,  but  reach 
their  greatest  development  in  the  Triassic. 

In  the  development  of  their  septa  the  Triassic  Ammonites  show  an  unexpected 
variety  of  form  and  complexity.  Certain  genera  {Sageceras,  Lecanites,  Lohites)  scarcely 
pass  the  goniatitic  stage  of  development ;  many  others  (MeeJcoceras,  etc.)  only  reach  the 
ceratitic  stage.  In  the  Arcestidae,  Tropitidae,  Cladiscitidae,  Ptychitidae  and  Phyllo- 
ceratidae  the  lobes  and  saddles  have  become  digitate.  Indeed,  in  Pinacoceras  is  found 
the  greatest  complexity  of  development  of  the  septa  that  has  been  observed  among  the 
Ammonites.  Along  with  the  typical  forms  the  Upper  Triassic  of  the  Alps  has  fur- 
nished  also  a  number  of  reversionary  types  or  aberrant  forms  (Gochloceras,  Rhabdoceras^ 
Ghoristoceras),  which  are  distinguislicd  by  reduction  of  the  septa  to  great  simplicity. 

With  the  Lias  a  fundamental  change  in  the  Ammonites  occurred.  Of  the 
numerous  Triassic  genera  and  families,  with  the  exception  of  the  Phylloceratidae,  all 
have  come  to  an  end  and  are  replaced  by  new  forms.  The  causes  that  made  the 
Cephalopods  so  rare  in  the  Ehaetic  are  unknown.  It  may  be  that  not  all  these 
groups  were  extinguished,  but  that  they  lived  on  in  other,  as  yet  unknown  regions, 
and  when  we  next  see  them  in  the  Jurassic  they  have  changed  beyond  recognition. 

In  the  Lower  Lias  the  Aegoceratidae  are  almost  the  only  forms ;  the  genera 
Psiloceras,  Arietites  and  Schlotheimia,  are  confined  to  this  stage.  In  the  Middle  Lias, 
along  with  the  Aegoceratidae,  are  represented  the  Harpoceratidae,  the  Amaltheidae 
(Oxynoticeras,  Amaltheiis),  the  Phylloceratidae  (Phylloceras),  the  Lytoceratidae 
(Lytoceras),  and  the  oldest  members  of  the  Stephanoceratidae  {Goeloceras,  Dactylioceras). 
It  is  noteworthy  that  in  the  Liassic  Ammonites  the  antisiphonal  lobe  is  frequently 
bifid  (as  in  the  Aegoceratidae  and  Amaltheidae). 

With  the  exception  of  the  Aegoceratidae  all  the  families  that  appeared  in  the 
Lias  lasted  into  the  Middle  and  Upper  Jurassic,  although  the  Harpoceratidae  are 
reduced  in  numbers,  and  perished  in  the  Malm  or  Upper  Jura.  The  only  new 
families  added  in  the  Middle  Jurassic  are  the  Haploceratidae  and  the  Cosmoceratidae. 
The  most  common  genera  in  the  Middle  Jurassic  are  :  Harpoceras,  Oppelia,  StephanoceraSj 
Sphaeroceras^  Morphoceras,  MacrocephaUtes,  Oecoptychius,  Reineckia,  Parkinsonia, 
Gosmoceras,  PerispMnctes,  Haploceras,  Phylloceras,  Lytoceras. 

In  the  Malm  are  found  nearly  all  those  genera  named  under  the  Middle  Jurassic, 
but  the  number  of  species  has  changed  greatly.  Thus  Harpoceras,  StephanoceraSj 
Reineckia,  Parkinsonia  and  Gosmoceras,  are  reduced,  while  Oppelia,  Haploceras, 
Olcostephanus,  and  especially  PerispMnctes  have  increased  greatly.  PerispMnctes  is 
decidedly  the  dominant  genus  in  the  Upper  Jurassic,  and  along  with  it  Asjndoceras, 
Simoceras  and  Peltoceras  show  a  large  number  of  species.  Aberrant  forms  are  rare 
in  the  Jurassic,  and  are  confined  to  a  few  species  of  Sjnroceras  and  Baculina. 

■  A  change  like  that  seen  at  the  beginning  of  the  Jurassic  takes  place  also  at  the 
end  of  this  period.  The  Ammonites  of  the  Creta,ceous  belong  largely  to  new  genera. 
Indeed  a  remarkable  metamorphosis  occurs  in  the  entire  habitus  of  the  Cephalopod 
fauna.  Only  the  oldest  Neocomian  beds  of  the  Alps  contain  a  few  species  that  had 
lived  in  the  Tithonian  epoch,  and  show  the  continuity  of  the  two  Systems.  The  least 
degree  of  change  is  shown  by  the  Phylloceratidae  and  the  Lytoceratidae.  In  place  of 
VOL.  I  2  X 


674 


MOLLUSCA 


Table  showing  Geological  Kange  of  Ammonoidea 


Families. 

i 

1 

i 

1 

1 

! 

1 

1  ^ 

i 

f3 
O 

1.  Clymeniidae 
Extrasiphonata 

1.  Bactritidae 

2.  Nautilinidae 

3.  Aphyllitidae 

4.  Tornoceratidae  . 

5.  Cheiloceratidae  . 

6.  Gephyroceratidae 

A.  Primordialinae  . 

B.  Beloceratinae     . 

7.  Prolecanitidae 

A.  Prolecanitinae    . 

B.  Noritinae  . 

C.  Medlicottiinae    . 

8.  Pinacoceratidae 

A.  Hedenstroemiinae 

B.  Sageceratinae 

C.  Carnitinae 

D.  Pinacoceratinae 

9.  Glyphioceratidae 

10.  Thalassoceratidae      . 

....  _ 

— 

11.  Ptychitidae 

12.  Tropitidae 

A.  Tropitinae 

B.  Haloritiuae 

C.  Sibiritinae 

D.  Celtitinae 

13.  Arcestidae 

A.  Popanoceratinae 

B.  Cyclolobinae 

C.  Arcestinae 

14.  Cladiscitidae     . 

1 

15.  Meekoceratidae 
A.  Lecanitinae 

B,  Meekoceratinae 

-—... 

16.  Gymnitidae 

17.  Hungaritidae     . 

... 

18.  Ceratitidae 

A.  Ceratitinae 

...  « 

B.  Tirolitinae 

— 

C.  Dinaritinae 

■     D.  Buchitinae 

— 

E.  Arpaditinae 

F.  Trachyceratinae 

G.  Choristoceratinae 

H.  Cochloceratinae 

1 

— 

1 

RANGE  OF  THE  AMMONOIDEA 


675 


Families, 

i 
1 

0 

1 

G 
O 
> 

£ 

1 
1 

Permian. 

• 

i 

i 

s 

•-9 

19.  Phylloceratidae 

A.  Monophyllitinae  . 

B.  Phylloceratinae   . 

20.  Lytoceratidae 

A.  Lytoceratinae 

B.  Macroscaphitinae 

C.  Turrilitinae 

21.  Aegoceratidae 

A.  Psiloceratinae 

B.  Arietitinae  . 

C.  Aegoceratinae 

D.  Polymorphinae    . 

22.  Harpoceratidae 

A.  Harpoceratinae    . 

B.  Oppeliinae  . 

23.  Amaltheidae 

A.  Amaltheinae 

B.  Hammatoceratinae 

24.  Haploceratidae    . 

25.  Stephanoceratidae 

A.  Dactylioceratinae 

B.  Steplianoceratinae 

C.  Cadoceratinae 

D.  Perispliinctinae    . 

E.  Morphoceratinae  . 

F.  Reineckiinae 

26.  Aspidoceratidae  . 

27.  Desmoceratidae 

A.  Desinoceratinae   . 

B.  Silesitinae    . 

28.  Cosmoceratidae 

A.  Cosmoceratinae    . 

B.  Hoplitinae   . 

C.  Acanthoceratinae 

D.  Crioceratinae 

E.  Scaphitinae 

F.  Placenticeratinae 

29.  Engonoceratidae 

30.  Pulchelliidae 

31.  Prioriotropidae     . 

i 

! 

1 



— 

— 

. 



— 

^ 







_ 

.. 



...» 



tlie  Harpoceratidae  we  find  the  Desmoceratidae,  of  which  the  genera  Desmoceras  and 
Silesites  especially  characterize  the  Neocomian  and  Gault,  and  Pachydiscus  the  liiglier 
stages  of  the  Cretaceous.  Of  the  Steplianoceratidae  the  genera  Perisphinctes  and 
Olcostephanus,  which  liad  survived  from  the  Jurassic,  are  extinguished  in  the  Lower 
Cretaceous.  In  the  i)lace  of  tlie  Jurassic  Cosmoceratidae  appear  HopliteSy  Douvilleiceras 
and  Acanthoceras.  A  peculiar  retrograde  development  of  the  septa,  a  reyersion  to  the 
ceratitic    stage,    is    seen    in     two    families    of   Cretaceous  Ammonites,   the    southern 


676 


MOLLUSCA 


PHYLÜM  VI 


Piilclielliidae  and  Eiigonoceratidae,  which  were  probably  connected  witli  tlie  younger 
Cosnioceratidac  (Hoplites).  The  Cretaceous  Ammonitic  fauna  derives  a  special 
character  from  tlie  great  development  of  aberrant  forms,  whicli  are  most  abundant  in 
the  Neocomian,  but  in  part  last  into  the  higher  stages  of  the  Cretaceous.  The  genera 
Macroscaphües,  Pictetia,  Hamües,  Anisoceras,  Turrilites,  BacuUtes,  Grioceras  and 
Scaphites  are  confined  exclusively  to  the  Cretaceous. 

The  sudden  extinction  of  the  Ammonites  at  the  end  of  the  Cretaceous  is  one  of 


Diagram  showing  the  Relationships  of  Paleozoic  and 
Early  Mesozoic  Ammonoids 


Tropitoidea 


Ptychiloidea    Lytoceratoidea 


Pinacoceratoidea 


3   ü 

II 


\> 


I 

I 

\ 

h 


i-rt  I 


£    I 

z  ; 
/ 


-O^x 


I 
I 
I 
I 
I 
I 
I 
I 
— i- 
I 
I 
I 
I 
s  I 
%    I 


\£    I 

I  I 


2    «  u    g 


/' 


# 


^      I 


i-l 


-e'   ^  > 


5:0-'- 


LOH 


^N 


the  most  reniarkable  phenomena  in  the  history  of  the  organic  world,  and  one  as  yet 
witliout  explanation.  Great  changes  in  conditions  of  life  must  have  taken  place  at 
the  border  between  Cretaceous  and  Tertiary  to  have  brought  about  the  extinction  of 
this  flourishing  and  highly  organised  group  of  animals  not  only  in  Europe,  but  also 
in  all  other  parts  of  the  world. 

The  System  of  nomenclature  now  commonly  in  vogue  has  placed  obstacles  in  the 
way  of  a  clear  view  of  the  general  characters  of  the  whole  group  of  Ammonoids. 
And  this  is  especially  unfortunate  because  in  more  recent  years  the  genera  and 
families  named  have  been  difficult  to  distinguish,  and  in  many  cases  have  received 
very  vague  definitions.  At  present  the  prevailing  tendency  is  to  subdivide  rather 
than  to  unite,  and  some  authors  are  in  a  fair  way  to  change  every  time-honoured 
species  into  a  special  genus  or  family. 

Few  divisions  of  the  animal  kingdom  have  left  such  a  perfect  record  of  their 


SUBCLASS  II 


DIBRANCHIATA 


677 


develojjmeiit,  and  sucli  a  great  mass  of  evidence  in  favour  of  the  theory  of  evolution 
as  liave  the  Amnionites,  Indeed,  in  this  group,  on  accoiint  of  tlie  nncommon  thinness 
of  tlie  shell,  internal  nioulds  are  of  as  mucli  importance  froni  tlie  standpoint  of  precise 
identification  as  those  specimens  whicli  have  the  shell  perfectly  preserved. 

Tlie  first  attempt  to  study  a  large  number  of  species  of  Ammonites  in  tlieir 
genetic  relationships  was  made  by  Waagen  in  the  series  of  Oppelia  supradiata. 
Similar  attempts  were  made  by  Neumayr  in  the  Phylloceratidae,  Perisphinctinae,  etc.  ; 
by  Hyatt  in  the  Arietitinae  ;  and  with  especial  minuteness  by  Leopold  Würtenberger 
in  the  Jurassic  groiips  Äspidocei-as,  Siinoceras,  Waagenia,  Peltoceras,  Periaphinctes  and 
Stephanoceras.  Also  Mojsisovics,  Uhlig,  Hang,  Douville,  Frech,  Diener,  Pompeckj  and 
others  have  paid  special  attention  to  the  genetic  relationships  of  the  various  groups  of 
Ammonites.  All  these  authors  come  to  the  conclusion  that  in  the  Ammonites  there 
are  numeroiis  genetic  series  of  which  the  development  may  be  followed  step  by  step  in 
the  species  that  occur  in  the  various  successive  strata. 

In  the  last  few  years  great  progress  has  been  made  in  the  study  of  the  Ammonite 
launas,  especially  of  the  later  Paleozoic  and  Triassic  horizons  ;  also  in  the  most  various 
divisions  of  the  many  branched  family  tree  of  the  Ammonites,  much  light  has  been 
thrown  upon  the  genetic  relationships  of  numerous  genera  and  families.  But  in 
spite  of  this  it  is  not  yet  possible  to  give  a  graphic  representation  of  the  development 
and  kinship  of  the  Ammonoidea  that  is  true  of  the  whole  group,  and  beyond  suspicion 
in  any  of  its  parts.  However,  in  the  above  diagram  a  tentative  effort  is  made  in  this 
direction,  and  in  this  scheme  the  probable  relationships  of  the  Paleozoic  to  the 
earlier  Mesozoic  genera  are  indicated  in  the  light  of  ^ 

the  present  Status  of  our  knowledge.    ' 

[The  foregoing  chapter  on  Ammonoidea  has  been  revised 
for  the  present  work  by  Professor  James  Perrin  Smith,  of 
Leland  Stanford  Junior  University,  California. — Editor.] 


Subclass  2.     DIBRANCHIATA  Owen. 


Cephalopods  with  only  two  arborescent  gills  in  the 
mantle-cavity  :  provided  round  the  mouth  with  eight 
or  ten  arms  hearing  suckers  or  hooks,  two  of  them 
(when  ten  in  all  are  present)  heing  often  developed 
into  long  tentacles.  Funnel  closed ;  ink-sac  usually 
present  Shell  internal,  or  if  external,  it  is  not 
chamhered ;  in  many  forms  entirely  wanting. 

The  body  of  the  Dibranchiates  or  Cuttle-fishes 
is  elongated,  cylindrical  or  sac-shaped,  and  fre- 
quently  provided  with  two  lateral  fin-like  append- 
ages.  The  anterior  cephalic  region  gives  ofF  a 
circlet  of  eight  or  ten  powerful,  muscular  arms, 
the  inner  sides  of  which  are  armed  with  suckers 
(acetahula),  or  a  double  row  of  hooks,  and  assist 
in  swimming  or  creeping,  and  also  serve  for  the 
capfcure  of  prey.  The  Sepioidea  have  two  of 
their  ten  arms  developed  into  very  long  tentacles 
which  bear  hooks  or  suckers  only  at  their 
thickened  extremities  (Fig.  1313).  The  lower  surface  of  the  suckers  is  disk- 
or  cup-shaped,  perforated  in  the  middle,  and  occupied  by  numerous  radially 


Fig.  1313. 

Enoploteuthisleptura.  Recent; 
Pacific  Ocean.  A,  Ventral  aspect. 
B,  Internal  shell  or  "pen." 


678  MOLLUSCA— CEPHALOPODA     .  phylum  vi 

arranged  muscle  fibres  ;  they  are  also  occasionally  furnished  with  horny  hooks 
or  Sharp  claws.  Each  siicker  is  able  to  create  a  partial  vacuum  by  pressiiig 
bhe  cartilaginous  rim  against  some  object  and  theri  contracting  the  inner 
folds,  and  hence  can  be  used  like  a  cupping-glass. 

The  jaws  resemble  those  of  Nautiloids  in  form,  but  are  never  calcified ; 
and  owing  to  their  perishable  nature,  usually  horny,  they  are  not  preserved  in 
the  fossil  State.  The  cartilage  of  the  head  forms  a  complete  ring  enclosing 
the  central  portion  of  the  nervous  system.  The  eyes  are  of  large  size, 
protected  by  a  capsule,  and  recall  those  of  vertebrates  in  structure. 

The  body  is  constricted  at  the  mantle  opening,  which  occurs  just  behind 
the  head,  and  at  this  point  on  the  ventral ,  surf ace  is  placed  the  respiratory 
orifice,  bounded  by  a  projecting  fold  of  the  mantle.  Here  also  terminates 
the  cylindrical  or  conical  funnel,  on  either  side  of  which  lie  the  dendriform 
gills ;  in  this  region  also  are  placed  the  anal  and  genital  openings. 

The  abdomen  is  sac-shaped,  and  contains  besides  the  viscera  and  circu- 
latory  Systems  a  rather  large  pyriform  vessel  called  the  ink-bag.  Its  reservoir 
is  filled  with  an  extremely  opaque  brownish-black  fluid,  which  can  be  voided 
at  will  through  an  excurrent  canal  terminating  near  the  anus.  Menaced  or 
alarmed,  the  creature  discharges  a  dense  cloud  of  ink,  which  serves  to 
conceal  its  retreat.  One  often  finds  within  the  body  of  fossil  Dibranchiates 
not  only  a  cast  or  mould  representing  the  ink-bag,  but  often  a  dark-coloured 
residuum  of  the  carbonaceous  particles  suspended  in  the  ink. 

The  abdomen  is  completely  covered  by  the  mantle,  which  is  a  thick  and 
frequently  brilliantly  coloured  muscular  envelope.  Traces  of  it  are  occasion- 
ally found  among  fossil  forms,  owing  to  a  slight  secretion  of  calcareous  matter 
within  it. 

Most  Dibranchiates  secrete  an  internal  shell  within  the  mantle.  Only 
among  the  Octopoda  is  a  shell  absent  entirely,  or  replaced  in  the  female  by  a 
thin,  simple,  unchambered  spiral ;  but  this  last  is  in  nowise  homologous  with 
the  usual  Dibranchiate  shell.  Spirula  has  a  spiral,  camerated  shell,  the  septa 
of  which  are  traversed  by  a  siphuncle,  and  the  coils  are  not  in  contacb.  It 
is  situated  in  the  hinder  portion  of  the  body  and  is  partially  enveloped  by  the 
mantle.  Among  extinct  Belemnites  the  internal  shell  consists  of  three  parts  : 
a  chambered  cone  (phragmacone),  which  is  prolonged  forwards  on  the  dorsal 
side  into  a  delicate  corneo  -  calcareous  proostracum,  and  is  inserted  at  the 
posterior  end  into  a  finger-like  calcareous  piece  called  the  guard  (sheath  or 
rostrum)  (Fig.  1314,  C). 

Some  living  Cuttle  -  fishes  have  a  horny,  elongated-oval,  feather-shaped 
proostracum  or  "pen"  (Fig.  1332),  which  is  situated  dorsally  in  a  closed  sac 
of  the  mantle.  It  is  sometimes  extremely  thin,  and  composed  of  conchyolin 
or  lime  carbonate.  The  sepion,  gladius,  or  "  cuttle-bone,"  as  the  shell  is  called 
when  calcified  in  some  genera,  exhibits  at  its  posterior  end  a  small  point  (the 
mucro)  corresponding  to  the  guard  in  Belemnites,  and  extends  in  front  as  a 
broad  shelly  plate,  like  a  proostracum.  This  forward  extension,  when  viewed 
from  the  front  side,  is  seen  to  be  covered  by  a  mass  of  thin  shelly  lamellae, 
which  correspond  to  the  septa  more  distinctly  observed  in  Belosepia. 

Many  living  Dibranchiates  are  gregarious,  and  swim  in  the  open  sea  in 
hordes ;  others  creep  on  the  bottom  or  lead  a  separate  existence  along  rocky 
shores.  They  are  extraordinarily  active,  voracious  animals,  and  prey  upon 
mollusks,  crustaceans  and  fishes.     A  few  species  are  esteemed  as  food  by  man. 


SüBCLAss  II  DIBRANCHIATA  679 

In  size  Dibranchiates  are  extremely  variable ;  some  forms  are  only  2  or  3  cm. 
long,  others  attain  gigantic  dimensions.  Architeuthis,  for  example,  reaches 
a  total  length  of  12  metres,  the  body  being  2*5  long,  and  over  2  metres  in 
circumference.  Its  arms  are  thick  as  a  man's  leg,  and  the  suckers  sometimes 
as  large  as  ordinary  coffee-cups. 

Dibranchiate  Cephalopods  are  divided  into  three  Orders,  as  follows  : — 
Belemnoidea,  Sepioidea  and  Octopoda. 

Order  1.     BELEMNOIDEA.     {Phragmophora  Fischer.)^ 

Shell  internal,  chambered,  and  the  septa  traversed  hy  a  siphuncle ;  conical  or  more 
rarely  spiral,  and  {with  the  exception  of  Spirula)  terminating  posteriorly  in  a  calcareous 
sheath  or  guard.     Arms  ten  in  numher,  provided  with  hooklets.     Trias  to  Recent. 

Save  for  tbe  genus  Spirula,  all  forms  belonging  to  this  suborder  are  extinct.  Their 
camerate  shells,  perforated  by  a  siphuncle,  betoken  a  kinship  with  Tetrabmnchiates,  but 
there  are  decided  differences  both  in  the  structure  and  function  of  the  shell.  Tetra- 
branchiates  have  the  shell  always  external,  enclosing  the  body,  but  in  Dibranchiates  it 
is  more  or  less  enveloped  by  soft  parts.  Genetic  connection  between  the  Belemnoidea 
and  Sepioidea  is  apparent,  and  although  their  shells  differ  in  form  and  structure,  yet 
a  rudimentary  phragmacone  persists  in  the  latter  at  the  posterior  end  of  the  skeleton. 
This  rudiment  is  much  more  perfectly  developed  in  Belosepia  of  the  Tertiary,  which  is 
a  connecting  link  between  Belemnoidea  and  Sepioidea.  It  is  possible  to  explain  the 
entire  internal  shell  of  Spirula  as  homologous  with  the  phragmacone  of  Belemnites. 
It  begins  as  a  globular  or  inflated  protoconch,  which  is  constricted  otf  from  the  first 
camera,  and  is  devoid  of  a  cicatrix.  The  siphuncle  originates  as  a  caecal  tube,  and  is 
continued  apicad  as  a  prosiphon,  the  same  as  in  Ammonoids. 

Family  1.      Belemnitidae  de  Blainville. 

Shell  composed  of  a  conical  camerate  phragmocone,  continued  on  the  dorsal  side  as  a 
proostracum,  and  an  elongated  solid  rostrum  or  guard.  Arms  ten  in  number,  of  equal 
length,  provided  with  hooklets,     Ink-bag  present.  ■  Trias  to  Eocene. 

This  family,  owing  to  its  great  morphological  diversity  and  geological  importance,  oecupies 
a  foremost  position  among  Belemnoidea.  The  shell  may  be  considered  as  the  prototype  of  that 
in  all  Dibranchiates,.  since  it  has  all  the  component  parts  fully  developed,  vvhereas  in  other 
groups  some  of  these  become  atrophied  or  wanting. 

The  shell  of  Belemnites  (Fig.  1314)  consists  of  three  fundamental  portions  :  (1)  A  solid 
calcareous  piece,  usually  much  elongated,  and  of  subcylindrical,  conoidal  or  fusiform  shape. 
This  is  called  the  guard  {rostrum,  osselet,  gaine,  Scheide),  and  is  excavated  at  its  anterior 

^  In  addition  to  the  literature  cited  nnder  the  head  of  Cephalopoda  {v.  antea)  see  the  following  : 
Angermann,  E.,  tjber  das  Genus  Acanthoteuthis  Münster,  etc.  Neues  Jahrb.  Miner.,  1902, 
supplem.  vol.  xv. — Blainville,  IL  D.  de,  Memoire  sur  les  Belemnites,  Paris,  1827. — Grick,  O.  C, 
On  Acanthoteuthis  and  Coccoteuthis.  Geol.  Mag.,  1896-97,  dec.  4,  vols  iii.,  iv. — [dem,  Notes  on 
Actinocamax.  Ibid.,  1904,  1907,  vols.  i.,  iv. — Idem,  On  the  Proostracum  of  a  Belemnite  from  the 
Upper  Lias  of  Alderton.  Proc.  Malacol.  Soc,  London,  1896,  vol.  ii.  pt.  3. — Idcm,  On  the  Arms  of 
the  Belemnite.  Ibid.,  1907,  vol.  vii.,  no.  5. — Idem,  Buccal  Membrane  of  Acanthoteuthis.  Ibid., 
1898,  vol.  iii.  pt.  I.—Idem,  On  Belemnocamax  bmoeri  from  the  Lower  Chalk.  Proc.  Geol.  Assoc, 
London,  1910,  vol.  xxi. — Danford,  ö.  G.,  Notes  on  the  Belemnites  of  the  Speeton  Clays.  Trans. 
Hüll  Geol,  Soc,  1906,  vol.  v. — Grossouvre,  A.  de,  Quelques  observations  sur  les  Bülemnitelles,  etc. 
Bull.  Soc.  Geol.  "France,  1899,  ser.  3,  vol.  xxvii. — Huxley  T.  II.,  On  the  Structure  of  Belemnitidae, 
etc.  Mem.  Geol.  Surv.  United  Kingdom,  1864,  Monogr.  ii. — Phillips,  J.,  Monograph  of  British 
Belemnitidae.  Palaeontogr.  Soc. ,  1865-70. — Suess,  A'.,  UeberdieCephalopoden-Sippe  Acanthoteuthis. 
Sitzber.  Akad.  Wiss.  Wien,  1865,  vol.  Ii.  —  Voltz,  P.  L.,  Observations  sur  les  Belemnites.  Paris, 
1827. — Idem,  Observations  sur  les  Belopeltis  ou  lames  dorsales  des  Belemnites.  Mem.  Soc.  d'Hist. 
Nat.  Strasbourg,  1840,  vol.  in.f—Appelöf,  A.,  Die  Schalen  von  Sepia,  Spirula  und  Nautilus. 
Kongl.  Svenska  Vetensk.  Handl.,  1893,  vol.  xxv. 


680 


MOLLUSCA— CEPHALOPODA 


PHYLUM  VI 


broad  extremity  into  a  conical  cavity  or  alveolus.  Within  the  alveolus  is  placed  (2)  the 
phragmaconc.  This  consists  of  a  conical  series  of  Chambers  (loculi),  the  septa  of  which  are 
piereed  at  the  ventral  niargin  Ibr  the  passage  of  the  siphuncle.  The  phragmaconc  begins  with 
a  globular  protoconch,  and  its  last  or  anterior  chamber  is  of  coniparatively  large  size.  It  is 
invested  with  a  thin  proper  wall  (conotheca),  which  is  prolonged  forwards  on  the  dorsal  side 
into  a  more  or  less  calcified  plate  called  (3)  the  proostracmn.  This  last  corresponds  to  the 
"  pen  "  of  living  cuttle-fishes.  There  is  evidence  that  its  anterior  margin  is  convex,  but  it  is 
so  extremely  thin  that  it  is  never  perfectly  preserved,  and  like  the  phragmaconc,  is  wanting 
in  by  far  the  greater  nnmber  of  specimens. 

Notwithstanding  the  fragmentary  condition  in  which  the  proostracum  invariably  occurs, 
it  is  possible  to  reconstruct  its  outlines  from  the  peculiar  conothecal  Striae,  or  markings  of  the 
membranous  substance  with  which  it  is  invested.  The  conotheca  is  made  up  of  three  very 
thin  superimposed  laminae,  the  outermost  of  which  usually  shows  the  markings  alluded  to 
most  distinctly  (Fig.  1314,  C).  The  conical  surface  of  the  phragmaconc  and  proostracum  is 
divided  by  Voltz  into  four  principal  regions  radiating  from  the"  apex  :  A  dorsal  area,  including 
all  the  Space  between  two  straight  lines  called  the  asymptotes,  which  extends  from  the  apex  of 
the  cone  as  far  as  the  apertiire.  This  area  occupies  about  one-fourth  of  the  circumference,  and 
is  marked  with  loop  lines  of  growth  convex  toward  the  front.  On  eitlier  side  of  the  dorsal 
area  and  separated  from  it  by  the  asymptotes  is  a  lateral  or 
hyperholic  area,  each  one  occupying  about  one-eighth  of  the 
circumference,  and  covered  with  very  obliquely  arched  lines 
in  a  hyperholic  form.  The  ventral  area  is  covered  with  numer- 
ous  transverse  Striae,  of  which  there  are  many  on  each  alveolar 
Chamber,  and  tliey  are  closer  together  the  nearer  they  are  to 
the  apex  of  the  phragmaconc.  The  Striae  of  the  dorsal  area 
are  less  numerous  than  those  of  the  rest  of  the  shell,  and 
usually  are  less  pronounced,  being  sometimes  imperceptible. 

"The  guard  oi Belemnites  consists  of  prismatic  calcareous 
fibres,  which  are  directed  perpendicularly  to  the  surface,  and 
radiate  in  all  directions  from  an  axial  line,  which  is  not 
strictly  central,  but  is  somewhat  nearer  the  ventral  than  the 
dorsal  side.  The  growth  of  the  guard  is  effected  by  the 
deposition  of  successive  conical  layers  or  sheaths,  which  are 
secreted  over  the  entire  surface,  but  are  thickest  behind,  and 
become  gradually  attenuated  in  front.  The  surface  of  the 
guard  is  sraooth  ;  or  may  be  wholly  or  partially  granulated 
or  wrinkled  ;  or,  again,  may  be  marked  with  branched  vascular 
impressions,  which  are  especially  conspicuous  on  the  ventral 
side.  In  many  cases  a  well-marked  groove — the  ventral  farrow 
— runs  from  the  edge  of  the  alveolus  backwards  on  the  ventral 
side,  exteiiding  for  a  short  distance  only,  or  reaching  to  the 
point  of  the  guard  (Fig.  1318,  C).  The  apical  portion  of  the 
guard  often  shqws  two  symmetrical  grooves  (the  dorso-lateral 
grooves)  which  diverge  slightly  and  become  shallower  as  they 
extend  forwards,  and  which  mark  the  dorsal  side  of  the  shell." 
(Nicholson). 

As  shown  by  vascular  impressions  on  the  rostrum,  the  shell 
of  Belemnoids  was  completely  enveloped  by  the  mantle.  Well 
preserved  impressions  of  the  animal  in  tlie  English  Lias  (Figs. 
1315,  .ß;  1327)  exhibit  an  elongated  form  of  body,  contracted 
anteriorly,  with  a  small  head  surrounded  by  ten  equal  arms. 
An  ink-sac  is  present,  and  the  arms  are  provided  with  hooks. 
The  maximum  size  attained  by  Belemnoids  is  between  2  and 
2-5  metres. 


Aulacoceras  Hauer    {Didyoconites   Mojs.)  (Fig.    1314). 
Guard  elongated,  clavate,  contracted  anteriorly,  tliickened 
^  in  the  posterior  third,  and  pointed  at  the  tip  ;  composed 

Upper  Trias ;  Rr)theistein7'riear  of  concentric,  loosely  superimposed  lameliae.  Each  side 
phragmacone"^.  ^]i,  Guard,  ^i/,*?  ^'^^^^^^  ^7  a  deep  broad  lateral  groove  reaching  from 
t^  ^°';V'°"  °iP^''"^''"'i'l""e  «ii^e'i  the  tip  as  far  as  the  anterior  alveolar  margin.     Phragma- 

10  Show   siphuncle  aml   siphonal  \  -i  .  o  ö 

funneis.  cone  at  least  twice  as  long  as  the  rostrum,  slowly  increas- 

.     ,  .  ^^o    11^    width    anteriorly,    ornamented    externally    with 

raised  longitudmal  lines,  which  are  crossed  on  the  dorsal  side  by  a  transverse  series 


Fig.  1314. 
Aulacoceras  reticulatum  Hauer, 
near 


Vlth    aj 

ries,  M 

m 


SUBCLASS  II 


DIBRANCHIATA 


681 


convex  toward  the  front ;  closely  resembling  Orthoceras.  Septa  rather  distantly 
spaced  ;  sipliuncle  marginal,  thin ;  proostraciim  unknown.  Guards  of  this  genuH 
are  rare,  biit  detached  phragmacones  are  not  unconunon.     Upper  Alpine  Trias. 

Atractitas  Gümbel.     Like  Äulacoceras,  but  guard  large,  smooth  and  witliout  lateral 
furrows.     Phragmacone  either  smooth,  or  with  fine  asymptotic  lines,  and  dorsal  area 

marked  with  extremely  fine 
growth  -  lines,  convex  toward 
the  front.  Guards  and  phrag- 
macones almost  always  occiir 
detached.  The  latter  were 
originally  mistaken  for  Ortho- 
ceratites,  but  are  distinguished 
by  their  marginal  siphuncle 
Hü-iiivGiaMMiu         -;      xeAruniiim.  ^^^b^xw^kh         ^nd    characteristic    conothecal 

Striae.  Upper  Trias  and  Lias 
of  the  Alps ;  also  Trias  of 
California. 


Fig.  1315. 

A,  Vertical  section  of  a  Belemnite,  the  proostracum  broken  away 
above  the  phragmacone.  li,  Belemnites  hrugierianuH  Miller.  Lower 
Lias  ;  Charmouth,  England.  Impression  of  complete  individnal.  Vs 
(after  Huxiey).     ö,  Restoration  of  a  Belemnite  shell. 

Abbreviations  :  R,  Rostrum  or  "guard";  l'h,  Phragmacone;  Po, 
Proostracum ;  a,  Apical  line  reaching  from  apex  of  guard  to  bottom  of 
alveolus  («) ;  h,  Impression  of  arms  ;  c,  Camerae  of  phragmacone  ;  i,  An- 
terior end  of  proostracum  ;  o,  Protoconch  ;  si,  Siphuncle  ;  x,  Ink-bag. 


Fig.  1316. 

Belemniteft  compressus.  Lias ; 
Gundershofen,  Alsace. 
Phragnuicoiie  with  well-pre- 
served  conotheca.  «,  Asymp- 
totic line  ;  h,  Hyperbolic 
area  ;  v,  Ventral  area. 


Xiphoteuthis  Huxiey.     Middle  Lias  ;  England.     X  elongata  Huxiey. 

Belemnites  Lister  (Figs.  1315-1319).  Name  first  applied  by  Agricola  in  1546. 
Guard  dactyliform,  subcylindrical  or  conoidal,  sometimes  short  and  tliick,  sometimes 
slender  and  much  elongated ;  retral  portion  tapering,  submucronate  or  obtusely 
rounded.  Owing  to  irregularity  in  secretion  of  calcite  layers  on  the  periphery  of  the 
guard  during  growth,  individuals  belonging  to  the  same  species  but  of  diflerent  ages 
frequently  dilfer  considerably  in  form.  Such  differences  are  well  illustrated  in  />. 
acuarius  Schloth.  The  young  are  sometimes  fusiform,  l)ut  grow  cylindiical  or 
conical  with  age.      About  350  species  are  known,  ranging  from  the  Lower  Lias  to 


MOLLUSCA— CEPHALOPODA 


PHYLUM  VI 

682 

Distribution  world-wide  ,  most  abimciant  ^i  ,  ^^  .^^^^  ^^^^.^  ^^  ^^^^  j^^^^ 

"*  a      a      ?>       and  Cretaceous,  this  genus 

®S)  »^      ig  scarcely  less  important 
than  the  Amnionites. 

Subgenera  :  Pachyteuthis 
Bayle  (Fig.  1318,  A).  Guard 
perfectly  smooth.  Confined 
to  tbe  Lower  Lias.  B.  acutus 
Mill. 

Megateuthis  Bayle  {Dac- 
fA/loteuthis  Bayle,  PaxiUosi) 
(Fig.  1318,  B).  Apex  of 
the  guard  with  two  or  tbree 


Fio.  1317. 
Belemnites  {Duvalia) 
dilatatus  Blv.  Neo- 
comian  ;  Justithal, 
Lake  of  Thuti,  Switzer- 
land. 


I 


Fig.  1318. 

A,  B.  (Pachyteuthis)  acutus  Miller.  Lower 
Lias ;  Lyme  Regis,  Dorsetshire.  B,  B.  {Mega- 
teuthis)  paoällosus  Schloth.  Middle  Lias ;  Metzin- 
gen, Würtemberg.  C,  B.  {Pseudohelus)  bipartitus 
Blv.  Lower  Cretaceous  ;  Castellane,  Basses 
Alpes,  a,  h,  c,  Dorsal  and  ventral  aspects  and 
cross-section,  l/j.  D,  B.  {Belemnopsis)  canalica- 
latus  Schloth.  Inferior  Oolite  ;  Würtemberg. 
E,  B.  (Belemnojms)  hastatus  Blv.  Oxfordian  ; 
Dives,  Calvados. 


Fig.  1319. 
Belemnites  {Actinocamax)  qnad- 
ratus  (Blv,).  Upper  Creta- 
ceous ;  Germany.  A,  Dorsal 
View  of  guard  with  defonned 
phragmacone  projecting  from 
alveolus.  B,  Ventral  aspect  of 
guard.  C,  Alveolus  from  above 
(after  Schlüter). 


usually  Short  grooves.     Middle  Lias  to  Lower  Cretaceous.     B.  paxülosus  and  B.  giganteus 
Schloth.  ;  B.  elongatus  Mill. ;  B.  subquadratus  Roem.,  etc. 

Belemnopsis  Bayle  (Hibolühcs  Montf. ,  Gastrocoeli,  Canaliculati,  Hastati)  (Fig.  1318,  D,  E). 
Guard  with  deep  and  usually  long  ventral  furrow  extending  from  alveolar  niargin  toward  the 
apex,  with  or  without  dorso-lateral  lines.  Middle  Jura  to  Middle  Cretaceous.  B.  canaliculatus 
Schloth. ;  B.  absolutus  Fisch. ;  B.  unicanaliculatus  Zeit. ;  B.  minimus  Lister. 

Pseiulobelus  Montf.  (Bipartiti)  (Fig.  1318,  C).  Guard  thin,  slender,  with  deep  dorso- 
lateral  grooves,  with  or  without  ventral  furrows.  Upper  Lias  to  Lower  Cretaceous.  B.  exilis 
d'Orb.  ;  B.  bipartitus  Blainv. 

^  Actinocamax  Miller  {Gonioteuthis  Bayle)  (Fig.  1319).     Guard  cylindrical,  submucronate, 
with  Short  but  very  deep  ventral  furrow  ;  anterior  end  foliaceous,  and  very  liable  to  dissolu- 


SUBCLASS  II 


DIBRANCHIATA 


683 


Fig.  1321. 
Diploconus  belem- 


nitoidea    Zittel, 
thoiiian 


Ti- 

Straraber" 


tion.  Phraginacone  only  very  slightly  inserted  in  the  guard,  the  two  portioiis  usually 
separated  by  an  mterval.  Middle  and  Upper  Cretaceous.  B.  suhvcntricosus  Wahlb. ;  B. 
quadratus  lilainv. 

BelemnitcUa  d'Orb.  (Fig. 
1320).  Guard  cylindrical,  with 
sliort,  deep  ventral  furroAV  fall- 
ing  short  of  the  alveolar  margin, 
Pliragniacone  inserted  in  guard. 
Vascular  impressions  often 
beautifully  preserved.  Upper 
Cretaceous. 

Diploconus  Zitt.  (Fig. 
1321).  Guard  short,  obtusely^ 
conical,  and  liaving  a  coii- 
centric  lamellar  structure,  not 
radial  and  fibrous.  Phragma- 
cone  reaching  nearly  to  the 
posterior  end  of  the  giiaid. 
Tithonian. 

Bayanoteuthis  Mun.- 
Chalm.  Guard  long,  cylind- 
rical, mucronate,  with  shallow 
lateral  grooves.  Dorsal  area 
rougheried.  Pliragmacone  very 
slender  and  long,  oval  in 
section.  Eocene  ;  Paris  Basin 
and  Ronca,  Italy.  B.  rugifer 
Schloenb. 

Vasseuria  Mun.  -  Chalm. 
Guard  slender,  elongated- 
conical,  with  a  nuniber  of 
longitudinal  grooves  extending 

from  the  apex.  Pliragmacone  more  than  one-half  as  long  as  the  guard.  Septa 
oblique,  their  necks  extending  from  one  septum  to  the  next.  Very  rare  in  the  Eocene 
of  Brittany. 

Belemnosis  Milne  Edw.  Very  rare  in  the  English  Eocene.  Styracoteuthis  Crick. 
Intermediate  between  Belemnitella  and  Bayanoteuthis.     Eocene  ;  Arabia. 

Beloptera  Blainv.  (Fig.  1322).  Guard  short  and  somewhat  s wollen  at  its  forwaixi 
end,  which  makes  a  slight  angle  with  the  pliragmacone  ;  on  either  side  it  is  expanded 
into  a  conical  projection.      Eocene. 

Belopterina  Mun.-Chalm.  Like  Beloptera,  but  without  the  lateral  wing-like 
expansions.     Eocene. 


Fig.  1320. 

Belemnitcs  (Belemnitella)  mucronatus 
Schloth.  Upper  Cretaceous  ;  Drenstein- 
furth,  Westphalia.  A,  B,  C,  Ventral,  dorsal 
and  lateral  aspects.    2/3, 


Fig.  1322. 

Beloptera  belem- 
nitoidea  Blv.  Calcaire 
Grossier ;  Paris  Basin. 
Ventral  aspect. 


Family  2.     Belemnoteuthidae   Zittel. 

Shell  composed  of  a  conical  phragmocone  and  proostracum,  the  guard  being  reduced 
to  a  thin  calcareous  or  horny  Investment  of  the  phragmacone.  Ten  arms  of  nearly  equal 
length,  each  heset  with  a  double  row  of  hooJcs.     Ink-sac  present.     Trias  and  Jura. 

Acanthoteuthis  Wagner  and  Münst.  {Belemnites  Quenst.  p.p. ;  Ostracoteiithis  Zitt.) 
(Figs.  1323-1325).  Phragmacone  with  numerous  septa,  and  siphuncle  having  short 
siphonal  funnels ;  enveloped  externally  in  a  thin  granulär  calcareous  layer  represent- 
ing  the  guard.  Surface  of  proostracum  divisible  into  a  broad  dorsal,  and  two  narrow 
lateral  areas  which  are  longitudinally  striated  and  taper  toward  the  front.  Dorsal 
area  ornamented  witli  fine  parabolic  and  also  straight  longitudinal  liiies  ;  anterior 


684  MOLLUSCA— CEPHALOPODA  phtldm  vi 

margin  rounded.     An  iniprÄssion  of  the  animal  found    in  the  Lithographie  Stone 


■X\ 


(f'  f  ^ 


Fio.  1324. 

Acanthoteuthis  speciosa 
Münst.  Lithographie 
Stone;  Bichstiidt.  A, 
Impression  of  shell,  the 
proostracum  accident- 
ally  bent  sidevvays.  Jl, 
rrnoslracuni  showing 
septa  and  siphonal 
funnels,    2/3. 


-Ä*-Ä 


VA  it5 


bw" 


Fl(i.  132: 


A  canthotruthü  speciosa 
Münst.  Lithographie, 
Stone ;  Solenhofen.  Pro- 
ostracum.   2/„^ 


Fig.  1323. 
AcantlwteutMs    speciosa     Münst.       Lithographie 
Stone  ;  Eichstädt,   Bavaria.      Impression  of  arms 
and  body.     1/2. 

shows  an  ink-bag  and  ten  powerful  arnis  about  the  liead, 
which  are  beset  witb  two  rows  of  opposite,  liorny,  falciforni 
liooklets.     Upper  Jura. 

Phragmoteuthis  Mojs.  (Fig.  1326).  Proostracum  twice 
as  long  as  the  conical  phragmacone,  with  dorsal  area 
bounded  by  asymptotic  lines,  and  two  shorter  lateral  areas  ; 
anterior  margin  of  all  areas  rounded.  Phragmacone  invested 
by  a  brownish  horny  layer  representing  the  guard.  Trias 
(Raibl  Beds). 

Belemnoteuthis  Pearce  {Gonoteuthis  d'Orb.)  (Figs.  1327- 
1328).  Like  Acanthoteuthis  but  with  smaller  and  curved 
pliragmacone,  which  is  not  produced  into  a  long  proostracum. 
Upper  Callovian  and  Lower  Cretaceöus. 


Family  3.     Spirulidae  Zittel. 

Shell  reduced  to  a  chamhered  phragmacone  coiled  into  a  flat 
Spiral,  the  coils  not  in  contact ;  situated  in  posterior  pari  of 
the  hody,  and  the  greater  portion  contained  within  the  mantle.  In 


SÜBCLASS  II 


DIBRANCHIATA 


685 


addition  to  the  cight  arins,  hvo  long  tentacles  vnthout  hooJcs  arc  ijlaced  between  the  third 
and  foitrth  pairs.     Oligocene  to  Recent. 


^  ,#. 


¥>} 

Fig.  1326. 

.(,  PhragmoteutMs  bisintiMta 
(Bronn).  Trias ;  Raibl,  Car- 
inthia.  Ph,  Phragmacone  ;  l'o, 
ProostracTim  ;  L,  Lateral  area 
of  proostracuin  ;  d,  Ink-bag. 
B,  Hooklets  of  arnis,  i/i  (after 
Suess). 


Fio.  1327. 

Bclcinnoteuthis  antiqua 
Pearce.  Oxford  Clay ;  Chris- 
tian Malford,  Wilts.  A,  Partly 
restored  specimen,  i/.j.  oc, 
Eyes  ;  m,  Mantle.  "  Other 
letters  as  in  Fig.  132(i.  B, 
Hooklet,  -^/i  (after  Mantell). 


Fio.  1328, 


Bdemnoteuthis  sp.  Oxford  Clay  ;  Gam- 
melshausen, Würtemberg.  A,  ü,  Dorsal 
and  ventral  aspects.  B,  Septum  and 
siphuncle. 


Fig.  1329. 

SpiruUrosim  bellardü  (Mich.).  Mio- 
cene  ;  Superga,  near  Turin,  Italy.  A, 
Side  View.  B,  Longitudinal  section.  R, 
Guard  ;  Ph,  Phragmacone.  i/j  (after 
Munier-Chalmas). 


SpiruUrostra  d'Orb.  (Fig.  1329).  Shell  composed  of  a 
short  triangulär  pointed  guard,  which  is  excavated  anteriorly 
for  the  reception  of  the  chambered  phragmacone.  The  latter 
begins  as  a  spiral,  but  speedily  becomes  straight,  and  has 
sejita  pierced  on  the  concave  ventral  side  by  the  marginal 
siphuncle.  Only  one  species.  Oligocene  of  Westphalia  and 
Upper  Miocene  of  Turin. 

SpiruUrostrina  Canavari.  Like  the  preceding,  but  guard 
reduced  to  two  small,  lateral  wing-like  appendages.  Neocene 
of  Sardinia. 

SpiriUa   Lain.  (Fig.    1330).      Shell   thin,   guard   wanting. 
Chambered    phragmacone    enrolled    with    the    ventral    side 
concave,  the  coils  not  in  contact,  composed  of  nacreous  sub- 
stance ;     septa     concave  ;     protoconch     globular 
ventral  and   marginal  in  position,  the  septal  necks  directed   "lencement  of  siphuncle; 

ö  A  T-,        .    1  -r.  ?'>  Prosiphon  ;  .<!,  Sii)huncle 

backwards  between   the  septa.      Prosiphon   present.     Recent  ;  (after  Munier-Chaimas). 


Fig.  1330. 

Spinila     peronii     Lara. 
Recent  ;    Pacific.       Longi- 
c,-    -r         1       tiidinal  section,  i/i.    a,  Pro- 
biphuncle    toconch  ;    c,    Caecal    com- 


686 


MOLLUSCA-CEPHALOPODA 


PHYLUM  VI 


•   loHf-   troi.icil  scas       For   description   of  the  animal   see  Keport  on   Spirula    by 
t^^^ti^:^r,  in  Appendfx   to    Ghallenoer  Reports,  Zoology,  part    Ixxxm., 

1895. 

Order  2.     SEPIOIDEA.     (Sqiüds  and  Cuttle-fishes). 
Shell  internal,  without  differentiated  phragmacone  and  guard,  hui  consisting  essenti- 
allZthTirroostracurn  or  ^^pen,^'  which  is  either  oval  or  narrow  and  elongated.     Arms 
tenin  numher,  provided  with  sucJcers  or  hooks.     Inh-hag  present. 


I 


Family  1.     Sepiophoridae  Fischer. 

sepion''  a  calcareous,  elongated-oval  plate,  terminating  posteriorly  in  a 


and  encloses  a  conical  cavity. 


Shell  or 
thickened  mucro  which  represents  a  rudimentary 

Siphuncle  loanting. 

The  thickened  posterior  mucro  is  a  rudimentary  stmcture  probably  corresponding 
^  to  the  guard  of  Belemnoids,  and 

its  conical  cavity  to  the  alveolus. 
Belosepia  retains  a  vestigial  cham- 
bering  but  no  siphuncle,  and  in 
Sepia  a  recognisable  phragmacone 
is  wholly  wanting.  These  forms 
are  undoubtedly  descended  froni 
Belemnoids  like  Beloptera. 

Belosepia    Voltz    (Fig.    1331). 
As  a  rule  only  the  posterior  portion 
of  the  proostracum  is   preserved. 
This  ends  in  a  bent  spine,  which 
is  thickened  anteriorly,  laterally 
expanded,  and  contains  near  the 
apejc    a     conical    alveolus.       The 
latter    shows   on  the   dorsal    side 
incomplete  traces  of  septa,  and  a 
wide       funnel  -  like       depression 
occupies  the  place  of  a  siphuncle. 
Eocene  ;   not  uneommon  in  Paris 
Basin  and  the  London  Clay.    Rare 
in  Claibornian  sands  of  Alabama. 
Sepia  Lam.  (Fig.  1332).    Shell 
or  "pen"  of   equal    length   with 
the        mantle,       elongated  -  oval, 
rounded      anteriorly,      thickened 
posteriorly  and  terminating  in  a 
short  mucro.      The  latter  contains 
a    conical   alveolus.      Dorsal  and 
ventral  walls  of  the  pen  consisting  of  two  brittle  calcareous  laminae,  separated  by  a 
horny  layer.     Internally  with  a  mass  of  extremely  fine  parallel  calcareous  lamellae, 
increasing    in    thickness    anteriorly ;    the    lamellae   separated  from   one   another  by 
minute  vertical  rods,  thus  producing  a  spongy  texture.     The  familiär  cuttle-bone  of 
commerce,  or  ossa  Sepiae,  is  the  pen  of  Sepia  oßcinalis  Linn.,  and  is  found  in  great 
quantities  along  the  coasts  of  certain  countries.     Several  Tertiary  species  known. 

(?)  Gampylosepia  Picard.     Muschelkalk  ;   Thuringia.     Belosepiella   De  Alessandri. 
Eocene  :  Paris  Basin. 


Fi(i.  1331. 
Belosepi/t  hlainvillei  Desh. 
Eocene  ;  Auvers,  near  Paris. 
A,  Posterior  end  of  Shell, 
ventral  aspect.  B,  Same  from 
the  sich;  (after  Deshayes). 


Fio.  1332. 


.S'qria  officinalis  Linn.  Recent. 
Ventral  view  of  shell.  a,  Cal- 
careous shelly  plates  represent- 
ing  vestigial  septation.  b,  Posi- 
tion of  rudimentary  phragma- 
cone in  front  of  mucro,  '^1^ 


SUBOLASS  II 


DIBRANCHIATA 


687 


Family  2.     Ohondrophoridae  Fischer. 

Internal  shell  in  the  form  of  a  much  elongated  thin  plate  or  jproostracum,  divided 
lenrjthwise  into  three  areas,  composed  of  conchiolin  or  of  alternating  layers  of  calcareous 
and  horny  matter,  thickened  posteriorly,  and  ivith  very  little  trace  of  any  chambered 
portion  or  phragmacone.     Jura  to  Recent. 

The  ineinbers  of  this  faiuily  show  a  further  reduction  of  the  guard  and  phragmacone 
than  occurs  in  the  stage  represented  by  Belemnotenthis,  and  their  horny,  non-septate 


Coccoteuthis  Jiastiformis  (Rüpp.). 
Lithographie  Stone ;  Eichstädt, 
Bavaria. 


Fi(i.  1334. 

Geoteuthis  bollensit,  Zieten. 
Upper  Lias ;  Holzmaden,  Wiirtem- 
berg.  Shows  ink-bag  and  cono- 
thecal  Striae.    1/3. 


Fig.  1335. 

Beloteuthis  schuebleri  Qnenst. 
Upper  Lias ;  Holzmaden,  Wür- 
teniberg.     1/2  (after  Quenstedt). 


Shells  shoiüd  be  compared  with  the  pen  of  the  common  squid  or  calamary,  Loligo 
vulgaris  Lam. 

Coccoteuthis  Owen  {Trachyteuthis  v.  Meyer)  (Fig.  1333).  Proostracum  elongated- 
oval,  composed  of  calcareous  and  horny  laminae,  rounded  posteriorly  or  with  but 
slightly  prqjecting  mucro ;  external  surface  roughly  granulated,  and  marked  by  lines 
diverging  from  the  apex.  These  lines  limit  the  boundaries  of  two  wing-like 
expansions  projecting  from  the  sides  of  the  elongated  median  j^ortion.  Impressions  of 
the  body  and  arms  are  occasionally  found  in  the  Lithographie  Stone  of  Bavaria. 
Upper  Jura. 

Leptoteuthis  v.  Meyer.  Proostracum  very  large,  thin,  narrowing  posterioriy  and 
composed  of  several  layers  of  calcareous  and  horny  layers.  Median  area  ornamented 
with  fine  undulating  transverse  Striae,  convex  toward  the  front,  and  separated  from  the 
lateral  areas  by  longitudinal  lines  diverging  from  the  apex.  Lateral  areas  marked 
with  oblique  inwardly  directed  lines,  and  bordered  by  lateral  expansions  which  are 
widest  posteriorly.     Upper  Jura  of  Southern  Germany.     L.  gigas  v.  Meyer. 

Geoteuthis  Münst.  (Fig.  1334).     Proostracum  composed  of  thin  alternating  horny 


688 


MOLLUSCA— CEPHALOPODA 


PHYLUM  VI 


\>\ 


v(M-s,  widest  in  front,  rounded  posteriorly, 

^niudinal    line,  and  boimded   on  either  side 

hyperbolic    Striae.       Ink-bag    frequently   preserved, 
Contents  transformed  into  a  jet-like    substance. 


Median  area  divided  into 

by  lateral  areas   with 

,   the 

It   is 


possible  to  dissolve  the  carbonaceous  particles  so  as  to 
prepare  a  wash  resembling  India  ink.  Upper  Lias  of 
Gennany,  France  and  England. 

Beloteuthis  Münst.  (Fig.  1335).  Proostracum  very 
tliin,  elongated,  feather  -  shaped,  broadly  rounded  pos- 
teriorly, pointed  in  front,  traversed  by"  a  median 
longitudinal  keel.     Upper  Lias  of  Würtemberg. 

Teuthopsis  Desl.  Lias.  Kelaeno  Münst.  Upper 
Jura.  Phylloteuthis  Meek  and  Hayden ;  Äctinosepia 
Wliiteaves,     Cretaceous  ;  Cana,da. 

Plesioteuthis  Wagner  (Dorateuthis  Crick)  (Fig.  1336). 
Proostracum  very  tliin,  long,  narrow,  lanceolate,  pointed 
posteriorly,  rounded  in  front,  with  a  median  longi- 
tudinal keel  and  a  raised  line  along  each  of  the  lateral 
edges.  Very  abundant  in  the  Lithographie  Stone,  and 
impressions  of  the  body  and  head  not  uncommon.  Also 
found  in  the  Cretaceous  of  Maestricht  and  Syria. 

Order  3.     OCTOPODA  Leach. 

Body  without  internal  shell,  and  only  the  female  of 
Argonauta  secreting  a  single- Chamber ed  external  shell. 
The  two  tentacles  are  not  present,  and  the  eight  arms 
bear  sessile  suckers  without  horny  rims.  Eye  relatively 
small,  without  sphincter-lihe  lid.  Body  short  and  rounded^ 
usually  without  fin-like  appendages, 

The  majority  of  genera  belonging  here  are  naked 
and  therefore  without  fossil  representatives.  The  small 
male  of  Argonauta  Linn.  is  without  a  shell,  but  the 
large  female  bears  a  delicate,  boat- shaped,  spiral  shell 
which  is  secreted  partly  by  the  mantle,  and  partly  by 
two  fin-like  ex^rnnsions  of  the  dorsal  arms.  Outer  surface 
of  Shell  ornamented  by  folds  and  tubercles,  and  two 
nodose  ventral  keels  are  present.  Late  Tertiary  (Pied- 
mont)  and  Recent. 

Galais  J.  de  C.  Sowb.  Body  short  and  round, 
provided  with  triangulär  lateral  fins,  not  united  behind. 
I;ili\ely  stout  tentacular  arms,  these  being  of  nearly  uniform 
length  and  .size,  and  each  bearing  a  single  row  of  suckers.  This  is  the  earliest  known 
üctopod  genua     Upper  Cretaceous ;  Mt.  Lebanon,  Syria 


Fig.  133(;. 

Plesioteuthis  prism 
Lithograpliic  Stone  ; 
A,  Impression  of  aini 
arms  and  iiik-hjt.L;.     /;, 


(liupi 


). 

list:MlL 
liowin^- 


Head 


Sil 


\v\\ 


Vertical  Range  of  the  Dibranchiata. 


A.    .•onipaml    Mith   Totraliranchiates,  the  Dibranchiata  are  of  minor  geological 
'"•■'""••      '  l".ir  ontuv  Organisation  renders  them  less  well  adapted  for  preserva- 


I   111    t 
»ruAini 


lir   n 


:.''■'.  '^'."^  ■"■^■"nliiigly  WC  shall  never  be  able  to  form  even  an 
,,„,,,,,„,,•.  ,  f  ;'"""■. ""l"^'tance  m  their  contemporaneous  faunae.  The  earliest 
.op.cu.Ulu.   of  l>el..nn.o,dea  appears  in  the  Trias  (Aulacoceras),  ^nd  the  Sepioidea 


suBCLASS  II  DIBRANCHIATA  689 

are  initiated  in  tlie  Lias.  From  wliat  grouj)  Dibranchiates  are  descended,  whether 
from  tlie  Tetrabranchiates  or  from  primitive  naked  ancestors,  \ve  bave  at  present  no 
certain  iiieaiis  for  deterniining.  They  appear  suddenly  in  a  liigh  state  of  develop- 
ment  ;  biit  a  still  more  remai'kable  fact  is  the  swift  culmination  and  decline  of  the 
group  of  Belemnoids.  In  contrast  to  the  small  number  of  forms  met  witli  in  the  Trias, 
we  find  even  in  the  Lias,  as  well  as  other  divisions  of  the  Jura  and  Lower  Cretaceoiis, 
a  rieh  and  varied  Belemnite  fauna.  At  the  close  of  the  Cretaceous  only  two  genera, 
Belemnitella  and  Äctinocamax,  persist  in  relatively  large  niimbers,  and  althoiigh  a 
few  antiquated  relics  of  the  same  stock  continue  into  the  Eocene,  their  rarity 
demonstrates  waning  vitality.  The  sola  living  representative  of  Belemnoids  is  the 
genus  Spirula. 

In  all  probability  the  Sepioidea  are  descended  from  Belemnoids.  Belosepia  of  the 
Tertiary  has  tolerably  distinct  indications  of  a  phragmacone,  but  in  Sepia  proper  the 
septation  has  become  vestigial.  Jurassic  Chondrophoridae  approximate  closely  to 
Recent  squids  and  cnttle-fishes.  All  the  evidenee  at  our  disposal  jiistifies  the  conclusion 
that  Mesozoic  Sej^ioids  possessed  an  essentially  similar  Organisation  to  that  of  Recent 
forms, 

[For  certain  changes  introduced  in  the  present  treatment  of  Dibranchiate  Cephalopods, 
as  compared  witli  the  original  German  edition,  the  Editor  alone  is  responsible,] 


VOL.  1  2  Y 


Phylum  VII.    ARTHROPOD A.    (Articulates.) 

Heteronomously  segmented  animals  with,  typically,  a  pair  of  appendages  to  each 
somite  of  the  hody  ;  the  whole  enclosed  in  a  chitinous  segmented  exoskeleton,  the  joint- 
ing  of  which  extends  to  the  appendages. 

In  the  Arthropoda  the  segments  are  unequally  developed,  and  the 
appendages,  primitively  locomotor  in  function,  may  be  modified  on  one  or 
more  somites  to  subserve  special  functions,  such  as  the  seizure  and  comminu- 
tion  of  food,  respiration,  Sensation,  copulation,  oviposition,  fixation,  etc. 
These  modifications  of  the  appendages  and  the  more  or  less  complete  union 
of  the  Segments  into  groups  may  result  in  the  difFerentiation  of  three  distinct 
regions :  head,  thorax  and  abdomen.  Of  these  regions  the  head  is  concerned 
largely  in  Sensation  and  feeding,  the  thorax  is  chiefiy  locomotor  in  function, 
and  the  abdomen  frequently  defensive. 

The  brain  lies  above  and  in  front  of  the  Oesophagus,  and  consists  of  a 
fusion  of  several  pairs  of  ganglia.  The  rest  of  the  central  nervous  System  con- 
sists of  a  chain  of  ganglia  lying  in  pairs  on  the  ventral  surface,  with  typically 
a  pair  in  each  somite.  Not  infrequently  there  is  a  more  or  less  extensive  con- 
centration  or  fusion  of  these  ventral  ganglia.  The  eyes  may  be  simple, 
aggregate  or  conipound,  with  in  some  cases  an  inversion  of  the  retinal  layer. 

■  Respiration  in  the  smaller  forms  is  by  the  general  surface  of  the  body, 
whereas  in  the  larger  certain  regions  become  specialised  for  this  purpose. 
When  respiratory  outgrowths  protrude  from  the  body  wall  they  are  known 
as  gills  or  hranchiae;  when  invaginated  they  are  termed  lungs  if  they  be 
lamellar  in  arrangement,  or  tracheae  if  they  consist  of  fine  tubes  ramifying 
through  the  tissues. 

Excretion  is  effected  either  by  "segmental  organs "  (true  nephridia) 
which  open  at  the  inner  end  into  the  true  body  cavity  (coelom)  and  at  the 
other  to  the  exterior,  or  by  diverticula  developed  at  the  hinder  end  of  the 
ahmentary  canal  The  nephridia  when  present  occur  in  only  a  few  segments 
of  the  body.  The  diverticula  of  the  alimentary  canal  (Malpighian  tubes)  are 
of  two  kinds-one  developed  from  the  mesenteron,  the  other  from  the  procto- 
(lacum.  In  all  Arthropods  the  ducts  of  the  reproductive  organs  are  apparently 
modified  nephridia,  and  the  organs  themselves  consist  of  gonads  developed 
rom  the  coelomic  walls  The  circulation  depends  upon  a  dorsal  heart  enclosed 
na  vascular  pericardial  sac,  and  metameric  blood  -  vessels  terminating  in 
lacunar     spaces.  ° 

Arthropods  are  divisible  into  three  groups  or  subphyla,  distinguished 
.c,„Ml,„.  ,„  the  natura  of  the  respiratory  organs,  segmentation  of  the  body, 

690 


cLAss  I  CRUSTACEA  691 

and  structure  of  the  appendages  as  follows :  Branchiata,  Myriapoda  and 
Insecta.  These  are  in  turn  divided  into  several  classes,  all  of  whicli  have 
fossil  representatives.  As  to  the  origin  of  the  Phylum,  Paleontology  afFords 
no  certain  evidence.  The  entire  Organisation  of  Arthropods  indicates  a  close 
relationship  with  Vermes,  and  especially  with  the  group  of  Annelid  Worms ; 
nevertheless,  the  differentiation  of  the  Arthropod  type  must  have  antedated 
the  Cambrian,  since  several  Orders  of  Crustacea  are  encountered  in  the  oldest 
fossiliferous  rocks  which  are  almost  as  widely  divergent  from  the  supposed 
ancestral  stock  as  many  Recent  forms.  The  relatively  late  appearance  of 
Myriapods,  which  are  the  most  worm-like  of  all  Articulates,  may  be  accounted 
for  by  their  terrestrial  habitat  and  the  destructibility  of  their  body  parts. 

SuBPHYLUM  A.    Branchiata. 

Arthropods  breathing  hy  means  of  gills  {or  Imigs  or  tracheae  modified  from  gills) 
developed  always  in  connedion  with  the  appendages.  Head  and  thorax  rarely  distinct, 
hut  usually  more  or  less  completely  united  in  a  cephalothorax.  The  genital  duäs 
open  to  the  exterior  near  the  middle  of  the  hody,  and  true  nephridia  usually  occur. 
Malpighian  tuhes,  when  present,  are  derived  from  the  mesenteron.  Anterior  append- 
ages all  multiarticulate,  the  basal  joints  of  one  or  more  pairs  serving  as  organs  of 
manducation. 

The  branchiate  Arthropods  include  two  classes :  Crustacea  and  Arachnida. 

Olass  1.    CRUSTACEA.^ 

Arthropods  of  usually  aquatic  habitat,  and  breathing  by  gills  (exceptionally 
through  the  general  body  surface) ;  with  one  or  two  pairs  of  appendages  (antennae)  in 
front  of  the  mouth,  the  first  of  which  is  purely  sensory,  and  several  pairs  of  post-oral 
appendages,  some  of  which  are  modified  into  organs  of  mastication.  Appendages  with 
typically  a  basal  Joint  (protopodite)  giving  rise  to  two  or  three  branches. 

The  segmentation  of  the  body  is  distinct  in  all  except  certain  parasitic 
forms,  where  it  is  lost  in  the  adult  stage  through  degeneration.  Usually  the 
demarcation  between  head  and  thorax  is  obscure,  and  the  anterior  region  of 
the  body  consists  of  a  cephalothorax,  the  number  of  whose  segments  varies 
within  wide  limits ;  this  being  in  sharp  contrast  to  the  Arachnids,  where  the 
Segments  are  constantly  six  in  number.  The  cephalothorax  is  frequently 
covered  by  a  chitinous  shell  or  carapace,  developed  from  the  dorsal  portion  of 
the  second  and  third  segments,  and  is  frequently  strengthened  by  deposits  of 
carbonate  and  phosphate  of  lime.     Although  the  carapace  is  usually  a  single 

1  Literature  :  Brongniart,  A.,  and  Bemarest,  Ä.  O,  Histoire  naturelle  des  Cnistaces  fossiles 
sous  les  rapports  zoologiques  et  geologiques.  Paris,  1822. — Müne  Jidioards,  IL,  Histoire  naturelle 
des  Crustaces,  3  vols.  Paris,  1834-40. —  Woodward,  H.,  and  Salter,  J.  W.,  Catalogue  and  Chart  of 
Fossil  Crustacea.  London,  1865. — Woodxoard,  H.,  A  Catalogue  of  British  Fossil  Crustacea. 
London,  1877. — Oerstaecker,  A.,  Crustacea,  in  vol.  v.  of  Bronn's  Classen  und  Ordnungen  des 
Thierreichs.  Part  1  (Cirripedia,  Copepoda,  Branchiopoda,  Poecilopoda,  Trilobita),  Leipsic,  1866- 
79  ;  part  2  (Isopoda  to  Decapoda),  1881-94.  —  Vogdes,  A.  W.,  A  Catalogue  of  North  American 
Palaeozoic  Crustacea  confined  to  the  non-trilobitic  Genera  and  Species.  Ann.  N.Y.  Acad.  Sei., 
1889,  vol.  V. — Grohhen,  K.,  Genealogy  and  Classification  of  the  Crustacea.  Sitzungsber.  Akad. 
Wiss.  Wien,  1892,  vol.  ci.  Translated  in  Ann.  and  Mag.  Nat.  Hist.  [6J,  vol.  xi. — Kingsley,  J.  S., 
The  Classification  of  the  Arthropoda.  Amer.  Nat.,  1894,  vol.  xxviii.  Reprinted  in  Tufts  College 
Studies,  No.  1,  1894,  with  bibliography. 


ß92  ARTHROPODA  phylüm  vii 

piece,  yet  in  some  forms  (Estheriiform  Branchiopods  and  Ostracods)  it  may 
consi^t  of  two  lateral  valves,  which  enclose  the  body  like  a  Pelecypod  shell ; 
or  of  four  parts,  as  in  certain  Phyllocarida  ;  or  again  (CuTipedia)  of  a  number 
of  calcareous  plates.  The  abdomen  is  usually  well  developed  and  its  Seg- 
ments are  free,  but  occasionally  it  becomes  greatly  reduced,  as   in    certain 

Entomostraca.  .  .  ,  .        -j     t    -^     •     4.1, 

The  total  number  of  body  somites  varies  within  wide  limits  m  the 
Entomostraca  and  Trilobita,  but  in  the  Malacostraca  they  are  almost  constantly 
twenty-one,  ranging  slightly  higher  in  the  Phyllocarida,  and  falling  shorter  in 
the  parasitic  Laemodipoda.  ^  i  1        i    • 

In  all  living  Crustacea  there  are  two  pairs  of  antennae,  although  m  some 
forms  (Apus,  Oniscids)  one  or  the  other  pair  may  become  greatly  reduced. 
In  the  Trilobites,  on  the  other  band,  but  a  single  pair  has  been  discovered. 
The  appendages  are  exceedingly  variable  in  form,  according  as  they  serve 
for  Sensation,  comminution  of  food  ("  mouth  parts  "),  locomotion,  respiration, 
capture  of  prey  or  copulation.  The  primitive  form  was  a  lamellar  appendage 
like  those  found  in  the  thoracic  region  of  Branchiopods,  but  the  typical  leg  is 
usually  stated  to  consist  of  a  basal  portion  (protopodite)  of  one  or  two  joints, 
and  a  distal  portion  made  up  of  an  inner  (endopodite)  and  a  lateral  brauch 
{exopodite).  In  many  cases  the  exopodite  becomes  greatly  modified  or  even 
entirely  atrophied  in  the  adult. 

Most  of  the  lower  Crustacea  escape  from  the  egg  in  a  larval  condition 
known  as  the  nauplius  stage.  In  the  nauplius  the  body  is  unsegmented,  there 
is  but  a  Single  median  eye,  and  but  three  pairs  of  appendages,  correspond- 
ing  to  the  two  pairs  of  antennae  and  mandibles  of  the  adult.  The  nauplius 
gradually  becomes  metamorphosed  into  the  adult  Crustacean,  the  changes  being 
accomplished  by  several  moults  of  the  external  chitinous  crust.  In  the  higher 
Crustacea  this  free-swimming  nauplius  stage  is  omitted,  the  animal  already 
having  the  form  of  the  adult  as  it  escapes  from  the  egg.  The  Decapods  have 
a  larval  stage  known  as  the  zoea,  in  which  seven  pairs  of  appendages  and  a 
segmented  abdomen  are  present.  These  larval  stages  are  of  great  value  in 
determining  relationships,  but  most  modern  authorities  regard  them  as  adaptive 
rather  than  ancestral;  or,  in  other  words,  it  is  not  believed  that  existing 
Crustacea  are  descended  from  an  ancestral  form  resembling  the  nauplius. 

Two  subclasses  are  recognised  :  Trilobita  and  Eucrustacea.  The  term 
Entomostraca  is  here  used  in  a  collective  sense  to  distinguish  the  lower  orders 
of  Eucrustacea  from  the  highest,  or  Malacostraca. 

Subclass  A.     TRILOBITA  Walch.     Trilobites.^ 

Marine  Crustacea,  with  a  variable  number  of  metameres  ;  body  covered  with  a 
hard  dorsal  shield  or  crust,  longitudinally  trilobate  into  the  defined  axis  and  pleura  ; 

^  Literature :  A.  General  y^ox\i%.—Brongniart,  A . ,  Histoire  naturelle  des  Crustaces  fossiles.  1 822. 
—Dcdmcm,  J.  W.,  Ueber  die  Palaeaden  oder  die  sogenannten  Trilobiten.  1828.  —  (?reew,  J., 
Monograph  of  the  Trilobites  of  North  America,  with  coloured  modeis  of  the  species.  1832.— 
Bnrnmster,  H  V^xii  Organisation  der  Trilobiten.  \UZ.  —  Beyrich,  E.,  Über  einige  böhmische 
Trilobiten,  Berlin,  1845-46. -Cor^a,  /.  C,  and  Haide,  J.,  Prodrom  einer  Monographie  der 
böhmischen  Trilobiten.  Prag  1847.-^/^,  /.,  Palaeontology  of  New  York,  vols.  i.-iii.,  1847-59.- 
ßarmmk  J.,  Systeme  Silurien  du  ceutre  de  la  Boheme,  vol.  i.,  1852  ;  Supplement,  1S7 2.— A7igelm, 
A.  i  . ,  Palaeontologia  Scandiuavica.  Part  i.  Crustacea  formationis  transitionis,  1854.  —Neiszkoivsld, 
^„Versuch  einer  Monographie  der  in  den  silurischen  Schichten  der  Ostseeprovinzen  vorkommenden 
irilobiten,  im.—Jloßmnn,  K,  Sämmtliche  bis  jetzt  bekannte  Trilobiten  Russlands.     Vcrhandl. 


3nden^ 
andl.9 


süBCLASs  I  TRILOBITA  693 

cephalon,  thorax  and  ahdomen  distind.  Cephalon  covered  with  a  shield  composed  of 
a  primitivehj  pentamerous  middle  piece,  the  cranidium,  and  two  side  pieces,  or  free 

Mineral.  Gesellsch.  St.  Petersburg,  1857-58. — Salter,  J.  W.,  A  Monograph  of  British  Trilobites. 
Palaeontographical  Society,  1864. — Idem  and  Woodward,  H.,  Ibid.,  1867-84. — Schmidt,  F., 
Revision  der  ostbaltischen  silurischen  Trilobiten.  Mem.  Acad.  Inip.  St.  Petersbourg,  1882-1907, 
ser.  7,  vol.  XXX.,  and  ser.  8,  vol.  xii, — Brögger,  W.  C,  Die  silurischen  Etagen  2  und  3  in  Kristiana- 
gebiet  und  auf  Eker,  1882. — Holm,  O.,  De  Svenske  Arterna  af  Trilobitslägtet  Illaenus.  Bihang 
Svensk.  Vetensk.  Akad.  Handl.,  1882,  vol.  vii.,  no.  3. — Matthew,  G.  F.,  Illustrations  of  the 
Fauna  of  the  St.  John's  Group,  1882-93.  —  Woodioard,  H.,  Monograph  of  the  British  Carboniferous 
Trilobites.  Palaeontogr.  Soc,  1883. — Hall,  J.,  and  Clarke,  J.  M.,  Palaeontology  of  New  York, 
1888,  vol.  vii.  —  Walcott,  C.  D.,  The  Fauna  of  the  Lower  Cambrian  or  Olenellus  Zone.  lOth  Ann. 
Rept.  U.S.  Geol.  Surv.,  1890. — Jaekel,  0.,  Über  die  Organisation  der  Trilobiten.  Zeitschr.  Deutsch. 
Geol.  Ges.,  1901,  vol.  liii. — Lake,  P.,  Monograph  of  British  Carabrian  Trilobites.  Palaeontogr. 
Soc,  1906-1913. — Lorenz,  T.,  Beiträge  zur  Geologie  und  Paläontologie  von  Ostasien,  der  Provinz 
Schantung,  etc.  Zeitschr.  Deutsch.  Geol.  Ges.,  1906,  vol.  Iviii. — Monk,  H.,  Beiträge  zur  Geologie 
von  Schantimg.  Jahrb.  Preuss.  Geol.  Landesanst.  Bergakad.,  1905,  vol.  xxiii. — Moberg,  J.  C,  and 
Segerberg,  C.  0.,  Bidrag  tili  Kannedomen  om  Ceratopygeregionen  med  Särskild  Hänsyn  tili  dess 
Utveckling  i  Fogelsangstrakten.  Acta  Universitatis  Lundensis,  1906. — Olin,  E.,  Om  de  Chasmops- 
kalken  och  Trinucleusskiffern  Motsvarande  Bildningarne  i  Skäne.  Acta  Universitatis  Lundensis, 
1906. — Raymond,  P.  E.,  The  Trilobites  of  the  Chazy  Limestone.  Annais  Carnegie  Mus.,  1905, 
1910,  vols.  iii.,  vii. — Idem,  and  Narraway,  J.  E.,  Notes  on  Ordovician  Trilobites.  Ibid.,  1906, 
1910,  vols.  iv. ,  vii. — Reed,  F.R.  C,  Lower  Palaeozoic  Trilobites  of  the  Girvan  District.  Palaeontogr. 
Soc,  1903-1906. — Idem,  The  Lower  Palaeozoic  Fossils  of  the  Northern  Shan  States.  Burma. 
Palaeont.  Indica,  1906. — Idem,  The  Cambrian  Fossils  of  Spiti.  Palaeont.  Indica,  1910. — Walcott, 
G.  D.,  The  Cambrian  Faunas  of  China.  Proc.  U.S.  Nat.  Mus.,  1906,  and  Smithson.  Mise  Coli., 
vol.  xxix.,  1911. — Idem,  Cambrian  Trilobites.  Geology  and  Paleontology.  Smithson.  Mise  Coli., 
1908-11,  vols.  liii.,  iv.  —  Weller,  S.,  Paleontology  of  the  Niagaran  Limestone  in  the  Chicago  Area. 
Bull.  Chicago  Acad.  Sei.,  1907,  no.  4. 

B.  Structure  and  Appendages  :  Burmeister,  II.,  vide  supra,  1843. — Billings,  E.,  Notes  on 
some  Specimens  of  Lower  Silurian  Trilobites.  Quar.  Journ.  Geol.  Soc,  1870,  vol.  xxvi.  —  Woodxoard, 
H.,  Note  on  the  Palpus  and  other  Appendages  of  Asaphus  from  the  Trenton  Limestone  in  the 
British  Museum.  Quar.  Journ.  Geol.  Soc,  1870,  vol.  xxvi. — Walcott,  G.  D.,  Preliminary  Notice 
of  the  Discovery  of  the  Natatory  and  Branchial  Appendages  of  Trilobites.  28th  Rept.  N.Y.  State 
Mus.  Nat.  Hist.,  1875. — The  Trilobite  ;  New  and  Old  Evidence  relatiug  to  its  Organization.  Bull. 
Mus.  Comp.  Zoology,  1881,  vol.  viii. — Novdk,  0.,  Studien  an  Hypostomen  böhmischen  Trilobiten. 
Sitzungsber.  Böhm.  Ges.  Wiss.,  Jahrg.  1879,  1886. — Glarke,  J.M.,  The  Structure  and  Development 
of  the  Visual  Area  in  the  Trilobite  Phacops  rana  Green.  Journ.  Morph ology,  1888,  vol.  ii. — 
Matthew,  W.  D.,  On  Autennae  and  other  Appendages  of  Triarthrus  beckii.  Amer.  Journ.  Sei.,  1893, 
(3),  vol.  xlvi. — Beecher,  G.  E.,  On  the  Thoracic  Legs  of  Triarthrus,  ibid.,  1893. — On  the  Mode 
of  Occurrence,  and  the  Structure  and  Development  of  Triarthrus  becki.  American  Geologist,  1894, 
vol.  xiii. — The  Appendages  of  the  Pygidium  of  Triarthrus.  Amer.  Journ.  Sei.  1894  (3),  vol.  xlvii. 
— Further  Observation«  on  the  Ventral  Structure  of  Triarthrus.  Amer.  Geologist,  1895,  vol.  xv. — 
The  Morphology  of  Triarthrus.  Amer.  Journ.  Sei.,  1896  (4),  vol.  i. — Structure  and  Appendages 
of  Trinucleus,  ibid.,  1895. — Studies  in  Evolution,  New  York,  1901. — The  ventral  integument  of 
Tribolites,  Amer.  Journ.  Sei.,  1902  (4),  vol.  xiii. — Lindström,  G.  Researches  on  the  Visual  Organs 
of  Trilobites.     Svensk.  Vet.  Akad.  Handl.,  1902,  vol.  xxxiv. 

C.  Ontogeny  :  Barrande,  J.,  vide  supra,  1852. — Beecher,  G.  E.,  The  Larval  Stages  of  Trilobites. 
Amer.  Geologist,  1895,  vol.  xvi. — MattJiew,  G.  F.,  Sur  le  developpement  des  premiers  Trilobites. 
Ann.  Soc.  Roy.  Mal.  de  Belgique,  1889,  vol.  xxiii. — vide  ante,  1882-93. 

D.  Systematic  Position :  Zittel,  K.  A.,  Handbuch  der  Palaeontologie,  1881-85,  vol.  iii. — Grundzüge 
der  Paläontologie,  1895. — Lang,  A.,  Text-book  of  Comparative  Anatomy.  English  Translation  by 
H.  M.  and  M.  Bernard.  1891. — Kingsley,  J.  S.,  Tlie  Classification  of  the  Arthropoda,  Amer. 
Nat.,  1894,  vol.  xxviii. — Bernard,  H.  M.,  The  Systematic  Position  of  the  Trilobites.  Quar.  Journ. 
Geol.  Soc,  1894-95,  vols.  1.,  li. — The  Zoological  Position  of  the  Trilobites.  Science  Progress, 
1895,  vol.  iv. — Woodioard,  H.,  Some  Points  in  the  Life-History  of  the  Crustacea  in  Early  Palaeozoic 
Times.  Quar.  Journ.  Geol.  Soc,  1895,  vol.  li. — Haeckel,  E.,  Systematische  Phylogenie  der 
wirbellosen  Tiere  (Invertebrata),  1896. — Beecher,  G.  E.,  Outline  of  a  Natural  Classification  of  the 
Trilobites.     Amer.  Journ.  Sei.,  1897  (4),  vol.  iii. 

E.  Classification:  Barrande,  J.,  vide  suj)ra,  1852. — Beecher,  G.  E.,  ante,  1897. — Brongniart, 
A.,  ante,  1822. — Biirmeister,  H.,  ante,  1843. — Gmda,  A.  J.  G.,  and  Hawle,  J.,  ante,  1847. — 
Haeckel,  E.,  ante,  1896. — IJalman,  J.  W.,  Oiu  Palaeaderna  eller  de  sä  kailade  Trilobiterna 
Stockholm,  1826. — Milne  Edwards,  IL,  Histoire  naturelle  des  Crustact's,  1834-40. — Quenstedt, 
F.  A.,  Beiträge  zur  Kenntniss  der  Trilobiten.  Wiegmann's  Archiv  für  Naturgesch.,  1837,  vol.  iii. 
— Emmrich,  H.  F.,  De  Trilobitis.  Dissertation,  1839. — Zur  Naturgeschichte  der  Trilobiten,  1844. — 


ßg_^  ARTHEOPODA  phylum  vii 

cheeks  which  may  he  separate  or  united  in  front,  and  carry  the  Compound  sessile 
eyes  when  present ;  cephalk  appendages  pediform,  consisting  of  five  pairs  of  hmbs, 
all  hiramous  and  fumtioning  as  ambulatory  and  oral  organs,  except  the  simple 
aiitemmles,  ivhich  arepurely  sensory.  Upper  lipforming  a  well-developed  hypostoma  ; 
umler  lip  p-esent.  Sornites  of  the  thorax  movable  upon  one  another,  varymg  m 
numherfrom  two  to  fwenty-nine.  Abdominal  segments  variable  in  number,  andfused 
toform  a  caudal  shield.  All  segments,  thoracic  and  abdominal,  carry  a  pair  of 
jointed  hiramous  limhs.  All  limbs  have  their  coxal  Clements  forming  gnathobases, 
which  hecome  organs  of  manducation  on  the  head.  Respiration  integumental  and  by 
branchial  fringes  on  the  exopodites.  Development  proceeding  from  a  protonauplius 
form,  the  protaspis,  by  the  progressive  addition  of  segments  at  successive  moults. 

The  Trilobites  constitute  a  group  of  extinct  marine  animals,  and  are 
related  to  the  stock  of  the  higher  modern  Crustacea ;  they  are  therefore  to  be 
considered  as  very  primitive  Crustaceans.  The  subclass  had  its  origin  in  pre- 
Cambrian  times.  Trilobite  remains  are  very  abundant  in  the  oldest  known 
fossiliferous  strata,  the  Cambrian,  where  they  exceed  in  number  and  diversity 
all  other  forms  of  animal  life.  They  continue  to  be  very  plentiful  during  the 
Ordovician  and  Silurian,  but  decline  in  the  Devonian,  and  the  few  last  sur- 
vivors  are  found  in  the  Carboniferous  and  Permian.  Probably  there  have 
been  more  than  two  thousand  species  described,  distributed  among  nearly  two 
hundred  genera.  These  numbers  give  an  idea  of  the  amount  of  difFerentiation 
and  specialisation  attained  by  Trilobites  during  Paleozoic  times. 

Carapace. — Trilobites  were  covered  or  protected  on  the  dorsal  side  by  a 
hard  crust  or  shield,  which  is  the  only  portion  commonly  preserved.  Their 
remains,  even  when  fragmentary,  are  recognisable  by  the  form  and  structure  of 
this  shield.  It  is  divided  longitudinally  by  two  dorsal  furrows,  or  grooves, 
into  three  portions  or  regions,  and  on  this  account  the  name  Trilobite  was 
first  given.  The  central  part  formed  the  axis  of  the  animal,  and  contained  the 
principal  organs,  as  the  viscera,  heart  and  chain  of  ganglia.  Transversely  the 
shield  is  divided  into  (1)  a  head  portion  called  the  cephalon ;  (2)  a  series  of 
joints  or  segments,  forming  the  thorax;  and  (3)  a  tail-piece  or  pygidium, 
forming  the  abdomen. 

The  test  seldom  exceeds  one  millimetre  in  thickness,  and  consists  of  thin 
laminae  of  carbonaceous  and  phosphatic  Compounds  of  calcium,  some  of  which 
were  originally  chitinous  substances.     The  laminae  are  frequently  traversed 

Goldfuss,  A.,  Systematische  Übersicht  der  Trilobiten  und  Beschreibung  einiger  neuen  Arten 
derselben.  Neues  Jahrb.  für  Mineral,  1843.— Jf'Coy,  F.,  On  the  Classification  of  some  British 
Fossil  Crustacea,  with  Notices  of  new  Forms  in  the  University  Collection  at  Cambridge.  Ann. 
Mag.  Nat.  Hist.,  1849  (2),  vol.  \\.—Chapman,  E.  J.,  Some  Remarks  on  the  Classification  of  the 
Trilobites  as  mtluenced  by  Stratigraphic  Relations  :  with  Outlines  of  a  new  Grouping  of  these 
Forms.  Trans.  Roy  Soe.  Canada,  1889,  vol.  xii.—Oürich,  G.,  Versuch  einer  Neueinteilung  der 
Irilobiten  Centralbl  Mineral.  Geol.  Pal.,  im .-Jaekel,  0.,  Über  die  Agnostiden.  Zeitschr. 
Deutsch.  Geol.  Ges.,  1909,  vol.  \xl~Pompeckj,  /.  F.,  Über  Calymmene,  Brongniart.  Neues  Jahrb., 
1898,  vol  1  — Äaymonti,  P.  E.,  Notes  on  Parallelism  among  the  Asaphidae.  Trans.  Roy.  Soc. 
Canada  1912  (3)  vol.  v.-7^eerf,  F  R.  0.,  Notes  on  the  Evolution  of  the  genus  Cheirurus. 
Geol.  Mag  1896  (4)  vol.  iy--Idem,  Blind  Trilobites.  Ibid.,  1898,  vol.  y.-Idem,  On  the  British 
spec.es  of  Conocoryphe.  lUd.,  1900,  vol.  vii.-7.^m,  On  some  Wenlock  species  of  Lichas.  IMd„ 
inl  /i  //''"  vV^'  ??^'  ^''^-  ^^— ^'^^"^'  The  Classification  of  the  Phacopidae.  Ibid.,  1905, 
vo  1  v.~Idm,  .Notes  on  he  genus  Lichas.  Quart.  Journ.  Geol.  Soc,  1902,  vol.  lviii.-/^m,  On 
1  .^..nns  hunu.!..ns  .eol.  Ma,^,  1912  (5),  vol.  ix.-Wedekind,  R.,  Klassifikation  der  Phaco- 
\n'U-u.   ^/rii.,-l,r.   |)..ut^cli.  (Icl.  (ies.,  1911,  vol.  Ixiii. 

rv   ',"  '"'!'''"f.'V'''?  ■  ,''T-^*''!\  ^'"    !'•'  ^  ^^'l-'i'^'^««^  '-^Hd  Annotated  Bibliography   of  the  Palaeozoic 
i-.ru>lac..,,.     (Hl.  Acad.  Sc,,  o.cas.  Papers,  iv.,  1893.     Supplement  in  Proc.  Cal.  Acad.,  1895,  vol.iv. 


SÜBCLAS8  I 


TKILOBITA 


695 


by  minute  poies,  which  give  a  punctate  appearance  to  the  test,  and  which  are 
sometimes  large,  as  in  Homalonotus  and  related  forms. 

The  carapace  is  somewhat  arched  or  convex,  generally  elongate-oval  in 
form,  and  usually  rounded  at  both  ends.  The  length  is  almost  invariably 
greater  than  the  width.  Yery  often  the  same  species  shows  a  broad  form, 
as  well  as  a  relatively  larger,  narrower  one.  The  former  was  considerediby 
Barrande  as  representing  the  female,  and  the  latter  the  male  individual.  The 
carapace  is  often  ornamented  with  spines,  teeth  and  knobs.  These  may  be  of 
the  nature  of  surface  Ornaments,  or  in  the  case  of  spines,  may  be  produced  by 
growths  from  the  genal  angles,  the  ends  of  the  segments  of  the  thorax  and 
pygidium,  or  the  spiniform  extension  of  the  pygidial  termination. 

The  carapace  does  not  often  terminate  at  the  margin  as  a  simple  lamellar 
plate,  but  is  turned  under,  and  forms  a  reflexed  margin,  or  douhlure,  which  is 
parallel  to  the  outer  edge,  but  is  separated  from  the  upper  surface  by  a  narrow, 
partially  included  space.  This  produces  the  hollow  spines  from  the  ends  of 
the  Segments,  from  the  genal  angles  and  from  the  pygidium.  In  rare  instances, 
the  spines  are  solid. 

The  axial  lohe,  or  middle  part,  is  defined  by  two  longitudinal  dorsal  furrows 
extending  the  whole  length  of  the  thorax,  and  also  over  more  or  less  ot  the 
cephalon  and  pygidium. 

The  pleura  are  the  two  lateral  areas  on  each  side  of  the  axis.  Thus,  there 
are  pleural  cephalic,  thoracic  and  pygidial  regions.  The  name  pleuron  (in 
the  Singular),  or  pleura,  is  especially  applied  to  the  extensions  from  the  axial 
portion  of  each  free  segment. 

The  Cephalon. — The  cephalon,  or  cephalic  shield  (Fig.  1337),  includes  all 
that  part  of  the  carapace  in  front  of  the  thorax.  It  comprises  the  hypostoma, 
epistoma,  the  free  cheeks  bearing 
the  eyes,  the  fixed  cheeks,  and  the 
glabella  ;  it  is  generally  semicircular 
in  form,  and  is  joined  along  its 
posterior  margin  to  the  thorax. 
The  postero  -  lateral  margins,  or 
genal  angles,  are  frequently  drawn 
out  into  spines.  Usually  there  is 
an  occipital  furrow  extending  across 
the  cephalon  parallel  to  the  posterior 
margin,  and  defining  the  occipital 
ring  or  segment. 

The  glabella  is  the  axial  portion 
of  the  cephalon,  and  is  defined  by 
the  primary  dorsal  furrows  (Fig. 
1337).  It  shows  typically  three 
oblique  or  transverse  furrows  in 
addition  to  the  occipital  ring,  mark- 

ing  the  limits  of  the  original  five  Consolidated  segments,  and  corresponding  to 
the  paired  appendages  of  the  ventral  side.  Sometimes  the  positions  of  the 
muscular  fulcra  are  also  indicated  on  the  dorsal  surface,  by  short  furrows,  or  by 
shallow  pits.  The  glabella  may  constitute  nearly  the  whole  of  the  cephalon, 
as  in  Deiphon  or  Aeglina,  or  it  may  be  narrow,  as  in  Earpes  and  Eurycare.  In 
some  cases  it  does  not  extend  over  half  the  length  of  the  cephalon,  as  in  Harpes 


Cf',plialon  of  DalTnanites  Jiaiu?vtanni 
(Brongt.).  Devonian  ;  Bohemia.  l, 
Limb  or  border;  fnn,  Marginal  furrow, 
a,  Genal  snines  ;  ql,  Glabella ;  If, 
Frontal  lobe  ;  U-ß,  Side  lobes  ;  l-S, 
Side  furrows  of  glabella  ;  so,  Neck 
furrow  ;  A,  Neck  ring  ;  @,  Facial 
suture  ;  oc,  Visual  surface  of  the  eyes  ; 
p,  Palpebral  lobe. 


696 


ARTHROPODA 


PHYLUM  VII 


The   hypostoma,^  or   labrum, 
Crustaceans,   and   consists   of   a 


Fig.  1338. 


Hypostomas. 


1^, 


A,  Corydocephalus  palviatus 
C,  Encrinurus  intercostatus,  side  and  front  views 
fafter  Noväk).  BB,  Anterior  edge ;  M,  Middle 
furrow  ;  E,  Posterior  furrow  of  the  middle  por- 
tion ;  /',  Posterior  edge ;  L,  Lateral  edge ;  y,  Pos- 
terior wing. 


and  Anlacopleura,  but  it  may  extend  to  the  frontal  border  as  in  Placopana  ov 
Ceraurus,  or  even  beyond,  as  in  Phacops,  Ämpyx  and  Conoliclms  The  entire 
Portion  of  the  glabella  which  lies  in  front  of  the  anterior  lateral  furrows,  and 
which  is  often  somewhat  enlarged  laterally,  is  called  the  frontal  lobe.  Some- 
times  the  limitation  between  the  glabella  and  fixed  cheeks  is  scarcely  defined, 
as  in  Illaenus  and  Dipleura.  Most  frequently,  however,  three  pairs  of  grooves 
can  be  distinguished  in  front  of  the  neck  furrow,  marking  the  pentamerous 
division  of  the  glabella  and  the  five  pairs  of  appendages  attached  to  the 
cephalon.  Sometimes  the  lateral  furrows  are  continuous  across  the  glabella, 
or  again,  they  may  be  directed  obliquely  (Triarthms),  or  even  form  longi- 

tudinal  grooves  (ConoUchas). 

is  homologous    to  the  upper   lip   of    other 
separate  plate  attached  by  an  articulating 
surface  or  line  to  the  reflexed  border  of 
the  cephalic  shield  (Fig.  1338). 

In  front  of  the  hypostoma  is  a  rostral 
area  sometimes  partly  occupied  by  a 
separate  plate,  the  epistoma  (Illaenus, 
Calymene). 

The  fixed  cheeJcs  are  lateral  extensions 
from  the  glabella,  to  which  they  are 
firmly  joined,  forming  the  central  portion 
of  the  cephalon.  They  may  occupy  more 
than  two-thirds  of  the  cephalon,  as  in 
Conocoryphe,  or  may  become  greatly  reduced,  as  in  Lichas  and  Froetus.  The 
cranidium  consists  of  the  glabella  and  the  fixed  cheeks. 

The  free  cheeks  carry  the  Compound  eyes,  and  are  separated  from  the 
cranidium  by  a  suture.  They  may  form  (a)  a  continuous  ventral  plate,  as  in 
Harpes,  Agnostus,  Crypiolithus,  etc. ;  they  may  include  (b)  a  greater  or  lesser 
portion  of  the  dorsal  surface,  being  either  entirely  separated  by  the  cranidium, 
or  (c)  meeting,  and  (d)  sometimes  coalescing  in  front.  They  are  widely 
separated  in  Ftychoparia,  in  juxtaposition  in  Asaphus,  and  continuous  in 
Dalmanites. 

The  geml  angles  are  the  posterior  lateral  angles  of  the  cephalon.  They 
may  be  rounded,  aS  in  Illaenus,  angular,  as  in  Goldius,  or  spiniform,  as  in 
Crypiolithus  and  Dalmanites.  They  belong  either  to  the  fixed  cheeks,  as  in 
Dalmanites,  or  to  the  free  cheeks,  as  in  Illaenus,  Goldius  and  Proetus. 

The  character  of  the  cheeks  is  especially  influenced  by  the  facial  sutures 
separating  the  free  cheeks  from  the  rest  of  the  cephalon.  They  appear 
as  sharply  defined  lines  beginning  either  at  the  posterior  margin,  or 
near  the  genal  angles,  or  on  the  lateral  margins,  and  extend  to  the  eyes, 
thence  around  the  inner  margin  of  the  visual  areas,  then  turn  anteriorly,  and 
either  unite  in  passing  around  the  front  of  the  glabella  or  remain  separate,  in 
which  case  the  sutures  terminate  in  the  anterior  margin.  The  position  of  the 
facial  sutures  thus  determines  the  relative  size  of  the  fixed  and  free  cheeks. 
After  the  death  of  the  animal,  or  after  moulting,  the  cephalic  shield  frequently 
teil  mto  pieces,  dividing  along  these  sutures. 

In  most  Trilobites,  the  existence  of  eyes  has  been  demonstrated,  though 

BihlnfÄ^k?\EÄ  ^^^  einigen  skandinavischen  Asaplnden. 


suBCLASs  I  TRILOBITA  697 

they  appear  absent  altogether  in  some  genera  (Conocoryphe,  Agnostus),  and  aje 
so  imperfectly  shown  in  others  that  for  a  long  time  they  remained  unrecognised 
(Agraulos,  Sao,  Ellipsocephalus,  etc.).  The  eyes  are  Compound,  and  are  elevated 
above  the  free  cheeks.  The  adjoining  area  of  the  fixed  cheeks  is  also  drawn 
upwards,  thus  forming  the  palpebral  lobe.  The  visual  areas  of  the  eyes  are 
borne  by  the  free  cheeks.  The  shape  of  this  area  is  extremely  variable,  but 
together  with  the  palpebral  lobe  it  generally  forms  a  truncated,  conical  or 
semilunar  elevation,  of  which  the  laterally  directed,  convex  side  is  occupied 
by  the  visual  surface  (Phacops,  Asaphus).  It  may  likewise  have  a  circular  or  oval 
form,  and  very  little  convexity  above  the  general  surface.  The  eyes  may  be 
quite  small,  as  in  Encrinurus  and  Trimerocephalus ;  large  and  prominent,  as  in 
Phacops,  Dalmanites  and  Proetus ;  or  very  large,  as  in  Aeglina,  in  some  species 
of  which  nearly  the  entire  area  of  the  free  cheeks  is  faceted,  and  the  visual 
surface  extends  around  the  entire  outer  borders  of  the  cephalon.  In  many  of 
the  primitive  genera  the  eyes  are  situated  at  the  distal  ends  of  raised  lines,  or 
eye  Ums,  extending  outward  from  near  the  forward  end  of  the  glabella. 

As  regards  their  structure,  the  Compound  eyes  of  Trilobites  are  recognised 
as  of  two  kinds.  In  the  first,  the  holochroal,  the  visual  area  is  covered  with  a 
continuous  horny  integument,  or  Cornea,  which  is  either  smooth  and  externally 
gives  no  idea  of  its  Compound  nature,  or  granulär,  on  account  of  the  facets 
beneath.  The  lenses  of  the  ommatidia  are  often  visible  by  translucence.  The 
second  type  of  structure,  the  schizochroal,  is  confined  to  the  single  family 
Phacopidae.  In  this,  the  visual  area  is  made  up  of  small,  round  or  polygonal 
openings  for  the  separate  facets  of  the  Cornea,  between  which  is  an  interstitial 
test  or  sclera.  The  size  of  the  facets  varies  from  more  than  0*5  mm.  in  some 
of  the  Phacopidae,  to  from  6-14  facets  in  the  width  of  1  mm.  in  other  Trilobites. 
The  number  and  arrangement  of  the  facets  also  vary  greatly  according  to  the 
genus.  Trimerocephalus  volborthi  shows  only  14  facets,  while  species  of  Phacops 
may  possess  from  200-300,  and  Dalmanites  hausmanni  has  600.  Among  the 
holochroal  eyes,  the  number  of  facets  is  much  greater ;  in  Goldius  palifer  it  is 
estimated  at  4000,  in  Ogygites  nobilis  at  12,000,  and  in  Caphyra  radians  as  high  as 
15,000.  Usually  the  facets  are  arranged  in  regulär,  alternating,  vertical  rows, 
or  quincuncially. 

Certain  genera  show  visual  organs  of  an  entirely  difFerent  type,  which  can 
be  best  regarded  as  simple  eyes,  and  correlated  with  the  ocelli  of  many  Crus- 
taceans.  Thus,  the  genera  Harpes  and  Tretaspis  present  from  one  to  three 
simple  elevations  or  granules  on  the  fixed  cheeks,  at  the  ends  of  eye-lines, 
while  the  ordinary  Compound  eyes  on  the  free  cheeks  are  absent. 

The  Thorax. — In  contrast  to  the  undivided  cranidium,  the  thorax  consists 
of  a  series  of  short,  transverse,  articulating  segments,  which  differ  in  number 
with  the  genus  and  species.  Every  thoracic  segment  is  divided  by  the  dorsal 
furrows  into  a  middle  portion  {axis,  tergum)  and  two  lateral  divisions  {pleura, 
epimera).  The  axial  portions  are  firmly  anchylosed  with  the  pleura,  and  are 
generally  strongly  convex,  with  the  posterior  margin  incurved.  Anteriorly 
they  bear  an  extension  below  the  general  surface,  and  separated  by  a  furrow. 
This  forms  a  surface  of  articulation  along  which  the  segments  are  movable,  and 
is  covered  by  the  edge  of  the  segment  immediately  in  front,  so  that  it  is  chiefly 
visible  in  coiled  or  disarticulated  specimens.  Barrande  distinguished  two 
types  of  pleura  :  (1)  furrowed  pleura  (püvre  ä  sillon),  which  have  a  diagonal 
furrow  on  the  upper  surface,  running  posteriorly  from  the  anterior  edge  near 


ARTHROPODA  phylum  vii 

698 


theaxis.  and  towards  the  free  ^^^^^^  ^SetZcÄ^;    || 

^^V;.r  It^tlVoTÄ^^^^^^^^^^^^^  0.  inner  poHion      The 

Ivtte^  exende  rom  the  axis  to  the  fulcrum  or  bend  i...  to  a  p  ace  where  the 
nleu  a  bend  more  or  less  abruptly  downward,  and  aUo  genera  y  toward  the 
^ear  The  dktal  portion,  beginning  at  the  Merum,  may  continue  o£  equal 
Ihkknel  and  be  rounded  or  obtuse  at  the  extremity,  or  it  may  decrease  :n 

^'"xt  nrl:ro;"thri:  seg^ents  dürers  exceedingly  among  different 
genera  Z  smallest  number,  two,  occurs  in  Agnostus  The  largest  number 
fo  £ar  observed,  twenty-nine,  is  found  in  some  spemes  of  Harpes.  A  Variation 
L  ^  bfnoted  even  anfong  the  .pecies  of  a  single  genu.  hence  this  ehar^cter 
is  not  of  general  application  for  purposes  of  Classification.     For  example, 


Fig.  1339.  Fi«-  l^*^- 

PvL'idium  of  Onygiocaris  huchi  (Brongt.).  Pygidium  of  Goldüis  umhellißr  (Beyr.). 

Ordovician,  Wales.  Devonian  ;  Boliemia. 

there  are  species  of  Ampyx  and  Aeglina  with  five  to  six  thoracic  segments, 
Fhillipsia  with  nine  to  fifteen,  Cheimrus  with  ten  to  twelve,  Cyphaspis  with  ten 
to  seventeen,  Ellipsoceplialus  with  ten  to  f ourteen,  and  Paradoxides  with  sixteen 
to  twenty.  In  general,  there  seems  to  be  a  sort  of  mutual  relationship 
between  the  number  of  thoracic  segments  and  the  size  of  the  pygidium. 
When  the  latter  is  large,  the  thoracic  segments  are  usually  few ;  but  if  small, 
the  number  of  thoracic  segments  is  large. 

The  Pygidium. — The  abdomen  of  Trilobites  is  commonly  known  as  the 
pygidium  (Fig.  1339),  though  sometimes  styled  the  caudal  shield  or  plate.  It 
consists  of  a  single  piece,  with  an  arched  upper  surface,  upon  which  may  be 
distinguished  regularly  a  median  axis  and  two  lateral  parts,  or  pleural  lobes, 
marked  more  or  less  distinctly  by  transverse  furrows.  Sometimes  it  bears 
considerable  resemblance  to  the  cephalic  shield  {Agnostus,  Eodiscus).  The 
pygidium  evidently  originated  from  the  anchylosis  of  a  number  of  similar 
segments.  The  potential  segmentation  is  often  so  strongly  marked  that  it  is 
very  difficult  to  recognise  the  dividing  line  between  the  thorax  and  pygidium, 
except  in  disarticulated  specimens.  Sometimes  the  evidences  of  segmentation 
disappear  entirely  or  are  but  faintly  indicated  on  the  lower  side.  When 
segmentation  along  the  axial  and  lateral  lobes  is  weak,  the  pygidium  differs 
considerably  in  appearance  from  the  thorax. 

The  axiü  may  extend  as  far  as  the  posterior  end  of  the  pygidium,  or  to 


süBCLASS  I  TRILOBITA  699 

any  part  of  the  length,  but  is  sometimes  reduced  to  a  short  rudiment  {Goldius, 
Fig.  1340),  or  it  may  be  even  eritirely  obscured  (Nileus).  The  number  of 
axial  Segments  normally  correspoiids  to  the  number  of  pygidial,  and  varies 
between  two  and  twenty-eight.  On  the  lateral  lobes,  all  or  at  least  a  part  of 
the  pleura  may  also  be  seen,  being  continued  from  the  axis  as  ribs  separated 
by  furrows.  In  these  cases,  the  furrowed  and  the  ribbed  pleura  can  usually  be 
distinguished,  but  not  infrequently  they  have  entirely  disappeared  as  surface 
features.  Many  of  the  Cambrian  Trilobites  are  conspicuous  for  their  small 
pygidium  and  elongated  thorax. 

The  outline  of  the  pygidium  is  most  frequently  semicircular,  parabolic  or 
elliptical ;  more  rarely  it  is  triangulär  or  trapezoidal.  The  margin  is  entire, 
less  commonly  dentate  or  spiny.  The  border,  as  in  the  case  of  the  cephalon 
and  the  pleura  of  the  segments,  has  a  reflexed  margin,  or  doublure,  which  in 
some  genera  attains  considerable  width. 

The  Ventral  Side. — The  ventral  side  of  Trilobites  is  commonly  inaccessible 
for  purposes  of  Observation,  since,  as  a  rule,  it  is  so  firmly  attaehed  to  the 
rock  that  the  organs,  even  though  present,  cannot  be  exposed  by  the  ordinary 
methods.  Furthermore  the  appendages  and  ventral  structures  are  so  thin 
and  delicate  that  the  most  favourable  conditions  are  necessary  for  their  pre- 
servation.  For  this  reason,  great  uncertainty  has  prevailed  regarding  the 
presence  and  character  of  the  legs  and  various  appendages.  After  a  careful 
preparation  of  their  inferior  side,  by  far  the  larger  number  of  Trilobites  show 
only  the  vacant  hollow  space  beneath  the  dorsal  shell,  and  the  hypostoma 
attaehed  to  the  reflexed  margin  of  the  cephalic  shield.  This  common  condition 
of  the  fossils  led  Burmeister,  in  1843,  to  the  assumption  that  all  organs  on 
the  lower  side,  as  in  Phyllopods,  were  originally  soft  and  fleshy.  Previous 
to  this,  however,  Linnaeus,  in  1759,  described  what  appeared  to  be  antennae, 
and  Eichwald,  in  1825,  announced  both  antennae  and  legs.  Altogether  the 
early  literature  down  to  1870  contains  quite  a  number  of  claimants  for  this 
discovery.  Most  of  the  evidence  is  manifestly  ^'erroneous,  and  the  two  or 
three  cases  which  bear  some  semblance  of  validity  are  too  obscure  to  be  of 
any  scientific  value. 

Billings,  in  1870,  published  the  description  and  figure  of  an  unusually 
well-preserved  Isotelus  gigas  from  the  Trenton  Limestone  of  Ottawa,  Canada. 
The  ventral  side  of  the  specimen  showed  eight  pairs  of  jointed  legs  on  each 
side  of  a  median  furrow.  Soon  after.  Woodward  described  an  antenna  or 
pediform  cephalic  appendage,  lying  beside  the  hypostoma  of  another  individual 
of  the  same  species.  Through  the  investigations  of  Walcott  (1875-94)  on 
Ceraurus  and  Calymene,  by  means  of  transverse  and  longitudinal  sections 
of  enroUed  specimens,  a  number  of  problems  have  been  settled  as  to  the 
characters    of    the    ventral 

side.       It    is     now    known    c  .^^^^^^.^^^^  i 

that     Trilobites     possessed     f         ,  --.^..^i*"^'''^^''**''^'^^*^ -"^^ 

a    thin,     external,     ventral    I  \    m.  ^ "^^^^^^^^^v 

membrane   attaehed  to  the    ^^^^  „     ,„,, 

,  ^^^^  Fig.  1841. 

renexea        margm  OI        tne  Median  vertical  section  of  Ceraurus  plpurexantliemus  Green,      c, 

cephalon     thoracic  SeßrmentS  Coplialon  witli  hypostoma  below  ;  tu,  Moiith  ;  Vy  Ventral  membrane  ; 

"             .'  °  ;,  Intestinal  canal  ;;<(/,  Pygidium  (after  Walcott). 

and  pygidium.     it  was  sup- 

ported  by  transverse  processes  which   became   thickened  with    age,  and    to 

these  the  legs  were  attaehed. 


^^Q  ARTHROPODA  phylüm  vii 

^tudwitrÄr^^^^^  to  its  termination  in  the  anal  open.ng  at  the 

^•^'Z;  :fth1  :tÄ— 'l^Sowledge  of  Mobite  s«.  have 
con.e  ffom  the  study  o£  numerous  very  perfectly  preserved  specimens  of 


Triarthrus  becki  Green. 


Fio.  1342. 

Utica  Sliale  (Ordovician) ;  (Rome,  New  York. 
2/1  (after  Beecher). 


A,  Dorsal,  and  B,  Ventral  aspect, 


Triarthrus  hecki  Green,  from  the  Utica  Shale  (Ordovician),  near  Rome,  New 
York.  Undoubted  antennae  in  this  form  were  discovered  by  Valiant,  and  first 
announced  by  Matthew  in  1893.  Subsequently  a  series  of  papers  was 
published  by  Beecher  on  the  detailed  structure  of  this  Trilobite,  which  is  now 
the  best  known  of  any  species,  and  necessarily  forms  the  basis  of  much  of  the 
following  summary  of  ventral  organs. 

In  the  median  line  anteriorly,  there  is  first  the  hypostoma  or  upper  lip,  at 
the  end  of  which,  and  opening  obliquely  back  ward,  is  the  mouth  (Walcott,  in 
Calymene).  In  Triarthrus  the  lower  lip,  or  metastoma,  is  a  convex  arcuate 
plate,  just  posterior  to  the  extremity  of  the  hypostoma.  At  the  angles  on 
either  side  are  two  small  elevations,  or  läppe ts. 


SUBCLASS  I 


TRILOBITA 


701 


Pairecl  Appendages, — All  segments  of  the  cranidium,  thorax  and  pygidium, 
except  the  anal  segment,  carry  appendages,  all  of  which  are  l)iramous  save  the 
anterior  pair.  The  anterior 
antennae,  or  antennules,  are 
attached  at  the  sides  of  the 
hypostoma,  and  consist  of  a 
simple,  many-jointed  flagel- 
lum  (Fig.  1342).  The 
caudal  rami  of  the  Cambrian 
genus  Neolenus  (Fig.  1343) 
are  long,  slender,  jointed 
and  attached  to  the  last 
segment  of  the  pygidium. 

The  typical  Trilobite 
leg  has  two  branches  arising 
from  a  basal  Joint,  or  coxo- 
podite,  which  is  prolonged 
into     a     gnathobase.       The  ^^^  i343 

inner  brancn,  or  endOpOdlte^  NeoUnus  serratuß  Romlnger.  Middle  Canibiiaii  ;  Burgess  Pass, 
has      typically      Six       jointS.    g-C.^  Microphotograph  showing  elongate  x  */i 

The    outer   brauch,   or  exo- 

podite,  has  a  long  proximal  Joint,  with  a  distal  multiarticulate  portion,  or 
the  proximal  Joint  may  be  flat  and  elongate,  forming  the  entire  exopodite, 
as  in  Neolenus  (Fig.  1343).  Long  setae  extend  posteriorly,  and  on  the  distal 
portion  they  are  so  crowded  as  to  make  a  conspicuous  fringe,  imparting  a 
characteristic  appearance  to  the  leg. 

Besides  the  antennules,  the  cephalon  bears  four  pairs  of  pediform  biramous 
appendages,  with  large  gnathobases  functioning  as  manducatory  organs.     Of 


Fig.  1344. 


Triarthriis  hrr]:i  r;tcen.  a,  Restored  thoracic  limbs  in  transvpisi 
soction  of  tlic  .uiimal  ;  }>,  Section  across  anterior  portion  of  pygidium 
c,  Section  across  ])(jslt'rior  portion  of  pygidium  (aftcr  Eeoclier). 


Fio.  134Ö. 

Triarthrus  becki  Green. 
Dorsal  view  of  second  thoracic 
leg,  with  and  withoxit  setae  and 
without  gnathobase.  e7i,  Endo- 
l)odite  ;  ex,  Exoi)odite  (after 
Beccher). 


these  the  first  may  be  correlated  with  the  posterior  antennae  of  higher  Crustacea. 
In  structure  and  function  they  are  true  mouth  appendages,  like  the  second 
pair  of  nauplius  limbs.  The  second  pair,  corresponding  to  the  mandibles  of 
higher  forms,  and  the  third  and  fourth,  corresponding  to  maxillae,  have  the 
same  structure  as  the  first,  with  large  gnathobases  and  fringed  exopodites. 
The  thoracic  and  abdominal  limbs  are  of  the  same  biramous  type.     The  endo- 


702 


ARTHROPODA 


PHYLUM  VII 


podites  are  jointed,  crawling  legs ;  posteriorly,  especially  on  the  pygidium, 
the  joiiits  become  flattened  and  leaf-like,  carrying  tufts  of  setae,  and  being 
adapted  for  swimming.  . 

The  exopodites  are  fringed  along  their  posterior  edges  with  narrow, 
oblique  lamellar  elements  becoming  filiform  at  the  ends,  thus  Converting  the 
limb  into  a  swimming  organ,  and  probably  also  serving  respiratory  functions 

(Figs.  1343,  1346).  ^  .    .     i.^     -,.  . 

Hahits.—\n  the  absence  of  any  closely  allied  recent  forms,  it  is  difficult  to 
reach  definite  conclusions  respecting  the  manner  of  life  of  Trilobites,  except 


Fig.  1346. 

Cryptolithus  tessellatus  Green.  Utica  Shale  (Ordovician) ;  Rome,  New  York.  A,  Left  half  of  pygidium  and 
three  thoracic  segments,  with  test  removed,  and  showing  fringes  of  the  exopodites.  B,  Ventral  aspect  of  same. 
tt,  Endopodite  ;  b,  Exopodite.    lo/i  (after  Beecher). 

such  as  are  based  upon  their  Organisation  and  mode  of  occurrence.  They  were 
undoubted  marine  animals,  since  their  remains  are  found  only  in  salt-water 
deposits,  associated  with  brachiopods,  cephalopods,  crinoids,  and  other  typical 
oceanic  forms.  Some  species  are  plentiful  in  calcareous  or  argillo-calcareous 
deposits,  with  thick-shelled  brachiopods,  gastropods  and  reef-building  corals, 
which  evidently  did  not  live  at  any  considerable  depth.  Other  forms  appear 
to  have  been  bottom  crawlers,  frequenting  either  muddy  or  sandy  bottoms ; 
and  again,  others  like  Cryptolithus,  lived  partly  buried  in  the  soft  mud.  On 
the  other  band,  many  species  indicate,  from  the  absence  of  visual  organs,  a 
comparatively  deep-water  habitat.  The  structure  of  the  appendages  of  many 
was  probably  such  as  to  permit  of  both  swimming  and 
crawling,  as  in  a  number  of  families  of  modern  Crustacea, 
and  they  were  therefore  restricted  neither  to  the  shore 
nor  to  the  bottom.  This  doubtless  explains  the  occur- 
rence of  the  same  species  in  very  different  Sediments. 

Power  of  Enrollment.— The  bodies  of  most  Trilobites 

were  capable  of  being  roUed  up  completely  like  many 

Fia  1.347.  ^^  ^he  Isopods  (Fig.  1347).     In  the  enrolled  condition 

caiyimne    mseH    Foerste.  ^^^  m^rgin  of  the  pygidium  is  closclv  applied  to  the 

SSXlSr"'^'''^''''^-   doublure  of  the  cephalon,  thus  entirely  concealing  the 

ventral  side  of  the  body.     The  thoracic  segments  over- 

lap,  and  admit  of  more  or  less  motion  upon  one  another.     The  pleura  also 


SÜBCLASS  I 


TRILOBITA 


703 


imbricate,  and  their  fulcra  are  provided  with  facets  upon  which  the  fulcra  of 
adjacent  segments  impinge.  The  ends  of  the  pleura  thus  protect  the  ventral 
surface  along  the  sides,  when  the  animal  is  enrolled.  Some  forms  appear  to 
have  possessed  the  power  only  to  a  limited  degree.  In  these,  the  creature  is 
usually  found  extended,  and  the  facets  on  the  fulcra  are  either  rudimentary 
or  absent. 

Ontogeny. — Minute  spherical  or  ovoid  fossils  associated  with  Trilobites 
have  been  described  as  possible  Trilobite  eggs,  but  nothing  is  known,  of 
course,  of  the  embryonic  stages  of  the  animals  themselves.  The  smallest  and 
most  primitive  organisms  which  have  been  detected,  and  traced  by  means  of  a 
series  of  specimens  through  successive  changes  into  adult  Trilobites,  are  little 
discoid  or  ovate  bodies  not  more  than  1  mm.  in  length.  This  first  larval  form 
has  been  named  the  protaspis,  and  has  been  found  to  be  the  typical  larval  form 
characteristic  of  all  Trilobites.  It  is  believed  to  approximate  the  protonauplius 
form,  or  the  theoretical,  primitive,  ancestral,  larval  form  of  the  Crustacea. 

The  simple  characters  possessed  by  the  protaspis  are  the  following,  as 
drawn  from  the  study  of  this  stage  in  all  the  principal  groups  of  Trilobites  : — 
Dorsal  shield  minute,  not  more  than  0*4  to  1  mm.  in  length ;  circular  or  ovate  in 
form  ;  axis  disti7ict,  more  or  less  strongly  annulated,  limited  by  longitudinal  grooves  ; 
head  portion  predominating ;  axis  of  cranidium  with  five  annulations ;  abdominal 
portion  usually  less  than  one-third  the  length  of  the  shield ;  axis  with  from  one  to 
several  annulations  ;  pleural  portion  smooth  or  grooved  ;  eyes,  when  present,  anterior, 
marginal  or  submarginal ;  free  cheeks,  when  visible,  narrow  and  marginal. 

The  changes  taking  place  during  the  growth  of  an  individual  are  chiefly 
the  following  : — Elongation  of  the  body  through  the  gradual  addition  of  the 
free  thoracic  segments ;  development  of  the  pygidium  ;  translation  of  the 
eyes,  when  present ;  modifications  in  the  glabella ;  growth  of  the  free  cheeks  ; 
and  final  assumption  of  the  mature  specific  characters  of  pygidium  and 
ornamentation. 

In  a  Classification  of  the  stages  of  development,  the  protaspis  has  the  rank 
of  a  phylembryo,  and  corresponds  in  value  to  the  protoconch  of  cephalopods, 
the  prodissoconch  of  pelecypods,  and  the  protegulum  of  brachiopods.  In  its 
geological  history  and  the  metamorphoses  it  undergoes  to  produce  the  perfect 
Trilobite,  accurate  information  can  be  gained  as  to  what  the  primitive  char- 
acters are,  and  the  relative  values  of  other  features  acquired  during  the  long 
existence  of  the  class. 

Of  the  developmental  stages  after  the  protaspis,  the  nepionic  may  be  con- 


Fio.  1348. 

Ptychoparia  Jdngi  Moek. 
Cambriaii.  A,  Protaspis  en- 
lar^Rfl.     B,  Adult  reduced. 


Fia.  1349. 

Sao  hirsuta  Barr.  Cambrian. 
^,  Protaspis  enlarged.  ü,  Adult 
reduced. 


Fio.  1350. 

Triarthrus  becki  Green. 
Ordovician.  A,  Protaspis  en- 
larged.     B,  Adult  reduced. 


sidered  as  including  the  animal  when  the  cephalon  and  pygidium  are  distinct, 
and  the  thorax  incomplete.  There  would  thus  be  as  many  nepionic  stages  as 
there  are  thoracic  segments.  The  neanic  stages  would  be  represented  by  the 
animal  with  all  parts  complete,  but  with  the   average  growth   incomplete. 


704 


ARTHROPODA 


PHYLUM  VII 


Final  pro^^ressive  growth  and  development  of  the  individual  would  fall  under 
the'epheblc  stage.  Lastly,  general  evidences  of  senility  would  be  interpreted 
as  belonging  to  the  gerontic  stage. 

Morphogeny. During  the  protaspis  stage,  several  moults  take  place  before 


Fig.  1351. 

Proetus  jxirviuscuhis  Hall. 
Ordovician.  A,  Protaspis 
mnch  enlarged.  B,  Adult 
slightly  enlarged. 


Fio.  1352. 

Acidaspis  tuberculata 

Conrad.       Devonian.       A, 

Protaspis     enlarged.        B, 

Adult  reduced. 


Fig.  1353. 

Dahnanitina  socialis  (Barr.). 
Ordovician.  A,  Protaspis  en- 
larged. B,  Adult  reduced. 
(Figs.  1348-1353  after  Beecher.) 


the  complete  Separation  of  the  pygidium  or  the  introduetion  of  thoracic  Seg- 
ments. These  bring  about  various  changes,  namely,  the  stronger  annulation 
of  the  axis,  the  appearance  of  the  free  cheeks  on  the  dorsal  side,  and  develop- 
ment of  the  pygidium  by  the  introduetion  of  new  appendages  and  segments, 
as  indicated  by  the  additional  grooves  on  the  axis  and  limb.  In  the  earliest, 
or  Cambrian  genera,  the  protaspis  stage  is  by  far  the  simplest  expression  of 
this  period  to  be  found.  In  the  higher  and  later  genera,  the  process  of 
acceleration  or  earlier  inheritance  has  pushed  forward  certain  characters  until 
they  appear  in  the  protaspis,  thus  making  it  more  and  more  complex. 

Taking  the  early  protaspis  stages  in  Solenopleura,  Liostracus  or  Ptychoparia, 
it  is  found  that  they  agree  exactly  with  the  foregoing  diagnosis  in  its  most 

elementary    sense.      Since    they    are    the 

characters  shared  in  common  by  all  larvae 

^T?\  I  MJ  1!^^         ^^  ^^^^  stage,  they  are  taken  as  primitive, 

Wjl  'yW  ^r  ^^^   accorded    that  value   in    dealing  with 

I  0  *^  adult  forms  possessing  homologous  features. 

^  Therefore,  any  Trilobite  with  a  large  elon- 

gate  cephalon,  eyes  rudimentary  or  absent, 

free  cheeks  ventral  or  marginal,  and  glabella 

long,  cylindrical,  and  with  five  annulations, 

would  naturally  be  placed  near  the  begin- 

ning  of  any  genetic  series,  or  as  belonging 

to  a  very  primitive  stock. 

Next  must  be  considered  the  progressive 
addition  of  characters  during  the  geological 
history  of  the  protaspis,  and  the  ontogeny 
of   the  individual   during  its  growth  from 
.,        .  ,       condition.      It   has  been   shown   by   Beecher    that 

there  is  an  exact  correlation  to  be  made  between  the  geological  and  zoological 

nrofTi'if?.^  important  structures  not  especially  noticeable  in  all  stages  of  the 
o    m  anvn  l""      ?^'  \^''^  ^^^""^  ^^^^^^«^  themselves  in  the  meta- 

Visual  areas  of  the  eyes,  when  such  are  present,  their  appearance  on  the  dorsal 


Fio.  1354. 

Sfto  hirmta  Barrande.  Cambrian  ;  Skrey 
Bohemia.  A,  Protaspis.  B-F,  Nepionic  stages 
of  development  (after  Barrande). 

the  larval  to  its  mature 


SUBCLASS  I 


TRILOBITA 


705 


shield  is  practically  simultarieous  with  these  organs,  and  before  the  eyes  have 
travelled  over  the  margin,  the  free  cheeks  must  be  wholly  ventral  in  position. 
When  first  discernible,  they  are  very  narrow,  and  in  Ptychoparia  and  Sao, 
include  the  genal  angles.  In  Dalmanites  and  Cheirurus,  however,  the  genal 
angles  are  borne  on  the  fixed  cheeks. 

Since  the  free  cheeks  are  ventral  in  the  earliest  larval  stages  of  all  but  the 
highest  Trilobites,  and  as  this  is  an  adult  feature  among  a  number  of  genera, 
which  on  other  grounds  are  very  primitive,  this  is  taken  as  generally  indicative 
of  a  very  low  rank.  The  genera  Harpes,  Agnostus,  Cryptolithus  and  their  allies 
agree  in  this  respect,  and  constitute  the  Hypoparia. 

The  remaining  genera  of  Trilobites  present  two  distinct  types  of  head 
structure,  dependent  upon  the  extent  and  character  of  the  free  cheeks.  In 
both,  the  free  cheeks  make  up  an  essential  part  of  the  dorsal  crust  of  the 
cephalon,  being  continued  on  the  ventral  side  only  as  a  doublure  or  infolding 
of  the  edge,  similar  to  that  of  the  free  edge  of  the  cranidium,  the  ends  of  the 
thoracic  pleura,  and  the  margin  of  the  pygidium.  They  may  be  separated 
only  by  the  cranidium,  as  in  Ptychoparia;  by  the   cranidium  and  separate 

AB  CD 


Fig.  1355. 

Ontogeny  of  Sao  Mrsuta  Barr.    (Opisthoparia)  A,  Protaspis.    B,  Cephalon  of  nepionic  individual.     C,  Cephalon  of 
later  nepionic  individual  having  eight  free  segments.     D,  Cephalon  of  adult  (froni  Beecher,  after  Barrande). 

epistomal  and  rostral  plate,  as  in  Illaenus  and  Homalonotus ;  or  they  may  be 
united  and  continuous  in  front,  as  in  Aeglina  and  Dalmanites.  One  type  of 
structure  is  distinguished  by  having  the  free  cheeks  include  the  genal  angles, 
thus  cutting  ofF  more  or  less  of  the  pleura  of  the  occipital  segment.  The 
genera  belonging  to  this  group  constitute  the  second  order — the  Opisthoparia. 

The  third  and  last  type  of  structure  includes  forms  in  which  the  pleura  of  the 
occipital  segment  extend  the  füll  width  of  the  base  of  the  cephalon,  embracing 
the  genal  angles.  The  free  cheeks  are  therefore  separated  from  the  cranidium 
by  sutures  cutting  the  lateral  margins  of  the  cephalon  in  front  of  the  genal 
angles.     Genera  having  this  structure  are  here  placed  in  the  order  Proparia. 

The  characters  still  to  be  noticed  have  chiefly  family  and  generic  values, 


Fig.  135G. 

Onlogeny  of  Dalmanitina  socialis  (Barr.).    (Proparia)  A,  Protaspis.     B,  Cephalon  of  individual  of  three  free 
Segments.     C,  Cephalon  of  one  with  seven  free  segments.    D,  Cephalon  of  adult  (from  Beecher,  after  Barrande). 

and  are  of  great  assistance  both  in  determining  the  place  of  a  family  in  an 
Order  and  the  rank  and  genetic  position  of  a  genus  in  a  family. 

There  is  very  satisfactory  evidence  that  the  eyes  have  migrated  from  the 
ventral  side,  first  forward  toward  the  margin,  and  then  backward  over  the 
cephalon  to  their  adult  position.     The  most  primitive  larvae  should  therefore 
VOL.  I  2  z 


706 


ARTHROPODA  phylüm  vii 


present  no  evidence  of  eyes  on  the  dorsal  shield.  Just  such  conditions  are 
fulfilled  in  the  youngest  larvae  of  Ptychoparia,  Solenopleura  and  Liostracus. 
The  eye-line  is  present  in  the  later  larval  and  adolescent  stages  of  these  genera, 
and  persists  to  the  adult  condition.  In  Sao  it  has  been  pushed  forward  to  the 
earliest  protaspis,  and  is  also  found  in  the  two  known  larval  stages  of  Triar- 
thrus.  Sao  retains  the  eye-line  throughout  life,  but  in  Triarthrus  the  adult  has 
no  trace  of  it.  A  study  of  the  genera  of  Trilobites  shows  that  this  is  a  very 
archaic  feature,  chiefly  characteristic  of  Cambrian  genera,  and  only  appearing 
in  the  primitive  genera  of  higher  and  later  groups.  It  first  develops  in  the 
later  larval  stages  of  certain  genera  (Ptychoparia,  etc.) ;  next  in  the  early  larval 
stages  (Sao) ;  then  disappears  from  the  adult  stages  (Triarthrus) ;  and  finally 
is  pushed  out  of  the  ontogeny  (Dalmanites). 

In  Ptychoparia,  Solenopleura,  Liostracus,  Sao  and  Triarthrus,  the  eyes  are 
first  visible  on  the  margin  of  the  dorsal  shield  after  the  protaspis  stages  have 
been  passed  through,  and  later  than  the  appearance  of  the  eye-lines ;  but  in 
Proetus,  Acidaspis,  Ceratarges  and  Dalmanites,  through  acceleration,  they  are 
present  in  all  the  protaspis  stages,  and  persist  to  the  mature  or  ephebic  condi- 
tion, moving  in  from  the  margin  to  near  the  sides  of  the  glabella.  Progression 
in  these  characters  may  be  expressed,  and  in  so  far  taken  for  general  applica- 
tion  among  adult  forms  to  indicate  rank,  as  follows  : — (1)  Absence  of  eyes; 
(2)  eye-lines ;  (3)  eye-lines  and  marginal  eyes ;  (4)  marginal  eyes ;  (5)  sub- 
marginal eyes ;  (6)  eyes  near  the  pleura  of  the  neck  segment. 

The  changes  in  the  glabella  are  equally  important  and  interesting. 
Throughout  the  larval  stages  the  axis  of  the  cranidium  shows  distinctly  by 
the  annulations  that  it  is  composed  of  five  fused  segments,  indicating  the 
presence  of  as  many  paired  appendages  on  the  ventral  side.  In  its  simplest 
and  most  primitive  state  it  expands  in  front,  joining  and  forming  the  anterior 
margin  of  the  head  (larval  Ptychoparia  and  Sao).  During  later  growth  it 
becomes  rounded  in  front,  and  terminates  within  the  margin.  In  higher 
genera,  through  acceleration,  it  is  rounded  and  well  defined  in  front,  even  in 
the  earliest  larval  stages,  and  often  ends  within  the  margin  (larval  Triarthrus 
and  Acidaspis),  From  these  few  simple  types  of  pentamerous  glabellae,  all 
the  diverse  forms  among  species  of  various  genera  have  been  derived,  through 
changes  affecting  any  or  all  of  the  lobes.  The  modifications  usually  consist  in 
the  progressive  obsolescence  of  the  anterior  annulations,  finally  producing  a 
smooth  glabella,  as  in  Illaenus  and  Niohe.  The  neck  segment  is  the  most  per- 
sistent of  all,  and  is  rarely  obscured.  The  third  or  mandibular  segment  is 
frequently  marked  by  two  entirely  separate  lateral  lobes,  as  in  Acidaspis,  Cono- 
lichas,  Chasmops,  etc.  Likewise,  the  fourth  annulation  carrying  the  first  pair 
of  maxillae  is  often  similarly  modified  in  the  same  genera,  also  in  all  the 
I'roetidae,^  and  in  Cheirurus,  Orotalocephalus,  Sphaerexochus,  Ampyx,  Harpes,  etc. 
Here  agam,  among  adult  forms,  the  stages  of  progressive  differentiation  may 
be  taken  as  indicating  the  relative  rank  of  the  genera 

The  comparative  areal  growth  of  the  free  cheeks  is  expressed  by  the 
gradual  «moving  of  the  facial  suture  toward  the  axis.  As  the  free  cheeks 
become  larger  the  fixed  cheeks  become  smaller.  In  the  most  primitive  pro- 
nJJ'ir^'''  Til  '"  ^"''^r.'  ^^^'^'^  ^"^  Cryptoliihus,  the  dorsal  Lface  of  the 
Zttl'"  ^  ^  ^  TT''^  \  '^'  "^^^  ^^^  fi^^d  «^^eks,  while  in  the  higher 
S  11  r'  f  ^"  ^^'^  '^''^'  ^^^^^^^  r^d^^^d  undl,  as  in  Styginalnd 
Phühpsia,  they  form  a   mere  border  to  the  glabella.     Therefore   the  ratio 


ä 


suBCLAss  I  TRILOBITA  707 

between  the  fixed  and  free  cheeks  furnishes  another  means  of  assisting  in  the 
determination  of  rank. 

The  pleura  from  the  Segments  of  the  glabella  are  occasionally  visible,  as 
in  the  young  of  Elliptocephala,  biit  usually  the  pleura  of  the  neck  segments  are 
the  first  and  only  ones  to  be  distingiiished  on  the  cephalon,  the  others  being 
so  completely  coalesced  as  to  lose  all  traces  of  their  individuality.  The  pleura 
of  the  pygidium  appear  soon  after  the  earliest  protaspis  stage,  and  in  some 
genera  {Sao,  Dalmanües)  are  even  more  strongly  marked  than  in  the  adult 
State,  and  much  resemble  separate  segments.  The  growth  of  the  pygidium  is 
very  considerable  through  the  protaspis  stage.  At  first  it  is  less  than  one- 
third  the  length  of  the  dorsal  shield,  but  by  successive  addition  of  segments  it 
soon  becomes  nearly  one-half  as  long.  In  some  genera  it  is  completed  before 
the  appearance  of  the  free  thoracic  segments,  all  of  which  are  added  during  the 
nepionic  stages.  An  Interpretation  of  these  facts,  to  apply  in  valuing  adult 
characters,  would  indicate  that  a  very  few  segments,  both  in  the  thorax  and 
pygidium,  may  be  evidence  of  arrested  development  or  suppression.  On  the 
other  band,  the  apparently  unlimited  multiplication  of  thoracic  and  especially  of 
abdominal  segments  in  some  genera  is  also  to  be  considered  as  a  primitive  char- 
acter  expressive  of  an  annelidan  style  of  growth.  Genera  like  Asaphus,  Phacops, 
etc.,  having  a  constant  number  of  thoracic  segments  accompanied  by  other  char- 
acters of  a  high  Order,  undoubtedly  represent  the  typical  Trilobite  structure. 

These  analyses  and  correlations  clearly  show  that  there  are  characters 
appearing  in  the  adults  of  higher  and  later  genera,  which  successively  make 
their  appearance  in  the  protaspis  stage,  sometimes  to  the  exclusion  or  modifica- 
tion  of  structures  present  in  the  more  primitive  larvae.  Thus  the  larvae  of 
Dalmanites  or  Proetus,  with  their  prominent  eyes  and  glabella  distinctly 
terminated  and  rounded  in  front,  have  characters  which  do  not  appear  in  the 
larval  stages  of  ancient  genera,  but  which  may  appear  in  their  adult  stages. 
Evidently  such  modifications  have  been  acquired  by  the  action  of  the  law  of 
earlier  inheritance  or  tachygenesis,  as  it  was  called  by  Hyatt. 

Position  in  the  Zoological  System. — Since  Trilobites  have  been  made  the  sub- 
ject  of  special  study,  they  have  been  commonly  classed  with  the  Crustacea,  and 
placed  near  the  Phyllopods  by  most  observers.  Quite  a  number  of  naturalists, 
however,  still  divorce  the  Trilobites  and  Limuloids  from  the  Crustacea,  and 
ally  them  with  the  Arachnids.  Leaving  aside  the  question  of  the  homologies 
of  Limulus,  it  is  a  fact  that  Trilobites  show  the  clearest  evidence  of  primitive 
Crustacean  affinities,  in  their  protonauplius  larval  form,  their  hypostoma  and 
metastoma,  the  five  pairs  of  cephalic  appendages,  the  slender  jointed  antennules, 
the  biramous  character  of  all  the  other  limbs,  and  their  original  phyllopodiform 
structure.  They  differ  from  Limulus,  not  only  in  most  of  these  respects,  but 
also  in  not  having  an  operculum.  From  Limulus  and  all  other  Arthropods 
they  are  distinguished  by  having  Compound  eyes  on  free  cheek-pieces,  which 
apparently  represent  the  pleura  of  a  head  segment  that  is  otherwise  lost, 
except  possibly  in  some  forms  of  stalked  eyes  and  in  the  cephalic  neuromeres 
of  later  forms.  The  most  recent  discussions  as  to  the  affinities  of  Trilobites 
are  to  be  found  in  the  papers  by  Bernard,  Kingsley,  Woodward  and  Beecher, 
where,  from  the  facts  presented,  the  relationships  of  these  animals  with  the 
Crustacea  follow  as  a  necessary  corollary. 

As  to  the  rank  of  the  Trilobites  in  a  classificatory  scheme,  there  is  also 
much  diversity  of  opinion.     They  have  been  long  regarded  as  an  order  of 


708  ARTHROPODA  phylum  vii 

Crustaceniis,  but  any  attempt  to  include  them  in  this  way  under  higher  groups, 
such  as  the  Entomostraca,  Malacostraca  or  Merostomata,  results  in  such  broad 
generalities  and  looseness  of  definition  as  to  render  these  divisions  of  little 
value.  The  present  state  of  knowledge  of  Trilobite  structure  and  develop- 
ment  is  in  favour  of  assigning  them  nothing  short  of  the  rank  of  a  subclass. 

In  nearly  every  particular,  the  Trilobite  is  very  primitive,  and  closely 
aerrees  with  a  theoretical  Crustacean  ancestor.  Its  afiinities  are  with  the 
known  subclasses  of  the  group,  especially  their  lower  Orders,  but  its  position 
is  not  intermediate.  The  more  primitive  characters  may  be  summarised  as 
follows  : — (1)  They  are  all  free  marine  animals ;  (2)  they  have  a  definite  con- 
figuration ;  (3)  the  larva  is  a  protonauplius-like  form ;  (4)  the  body  and 
abdomen  are  richly  segmented,  and  the  number  of  segments  is  variable ;  (5) 
the  head  is  typically  pentamerous ;  (6)  the  thorax  and  abdomen  are  always 
distinct,  the  number  of  segments  in  each  being  variable;  (7)  all  segments 
except  the  anal  bear  paired  appendages ;  (8)  all  appendages  except  antennules 
are  biramous ;  and  (10)  the  coxal  elements  of  all  limbs  form  gnathobases, 
which  become  organs  of  manducation  on  the  head.  Walcott  has  recently 
discovered  (1912)  the  appendages  of  the  Cambrian  trilobitic  genus  Neolenus 
and  those  of  other  Crustaceans,  which  indicate  that  the  Trilobite  is  a 
Crustacean  intermediate  in  structural  Organisation  between  the  Branchiopoda 
and  the  Merostomata. 

Classification. — Barrande  gives  a  complete  räsumö  of  the  classifications 
applied  to  Trilobites  down  to  1850,  and  shows  in  a  very  satisfactory  manner 
the  weak  points  of  each,  furnishing  strong  reasons  as  to  why  they  are  un- 
natural and  therefore  untenable.  The  underlying  principles  *of  these  early 
attempts  at  a  Classification  are  here  briefly  summarised.  (1)  The  first  Classifi- 
cation of  Trilobites  was  advanced  by  Brongniart  in  1822,  in  which  all  the 
forms  previously  known  as  Entomolithus  paradoxus  were  shown  to  belong  to  five 
distinct  genera.  (2)  Dalman,  1826,  made  two  groups,  based  upon  the  presence 
or  absence  of  eyes.  (3)  Quenstedt,  1837,  recognised  the  number  of  thoracic 
segments  and  the  structure  of  the  eyes  as  of  the  greatest  importance.  (4) 
/^N  n  r,,  ''  ■^^^^'  ^onsidered  the  power  of  enrollment  as  of  prime  value. 
(D)  Ixoldfuss,  1843,  established  three  groups  depending  on  the  presence  or 
absence  of  eyes  and  their  structure.  (6)  Burmeister,  1843,  accepted  the  two 
divisions  of  Milne  Edwards,  and  laid  stress  on  the  nature  of  the  pleura  and  the 
size  of  the  pygidium.  (7)  Emmrich's  first  scheme,  1839,  was  founded  on  the 
süape  ot  the  pleura,_the  presence  or  absence  of  eyes  and  their  structure.  (8) 
wtfW  fl.  T'f'^*'''''  ""^  ^^'  ''^"  ^^^^^^'  P^blished  in  1844,  depended  on 
d^vi^ion.  w!     t""^?  Z^l  '""^P"''^  "^  ^^^^^  ^^  ^''^  segments,  and  the  minor 

Dvlidial  Ir  '  ^ tf.^  all  Trilobites  in  two  groups,  one  having  an  entire 
M'C^^f  1  m^T'r ..  ^'  ''^'^  ^^'^  '^'  P^S^^^™  l^b^d  «r  denticSate.  (10) 
divtio;al  ch^^^^^^^^^  the  presence  or  absence  of  a  facet  on  the  pleura  for  a 
tTtTtLes  not  Hiff  this  IS  an  indication  of  the  relative  power  of  enrol- 
Burme  ster      7it\p  ""'''•'""{  ^'"^  '^'  ^^^^^^«  ^^  ^^1^^  Edwards  and 

the Tchem  s  of  m  '  ^"^  '  Review  brought  down  to  1885,  includes  in  addition 
the  bfsis  of  itilJi '"'"^'i  '''''  .'"^  (1')  ^^1^^^'  1864,  and  remarks  that 
has   ne   her  ^   j^fjf  ^Seneral  grouping,  namely,  the  structure  of  the  pleura, 

BarrrnlandSa^?.r.f^'''^'^^  "  morphological  significance.  Both 
i3arrande  and  balter  recognise  nearly  the  same  fan^ilL  w,-fi.^.i,-.i..  a;^^ . 


nearly  the  same  families,  with  slight  difFerences, 


SUBCLASS  I 


TRILOBITA 


709 


aiid  the  latter  adopts  a  division  into  two  lines,  based  on  the  number  of  body 
rings  and  size  of  the  pygidium.  These  include  and  are  themselves  included 
in  four  groiips,  foundcd  on  the  presence  and  form  of  the  facial  suture  and  the 
structure  of  the  eyes.  (13)  Chapman,  in  1889,  proposed  four  suborders  or 
primary  groups  based  purely  upon  arbitrary  features  of  general  structure  and 
configuration,  especially  the  form  of  the  glabella,  whether  wide,  conical  or 
enlarged.  (14)  Haeckel,  in  1896,  divided  the  Trilobites  into  two  Orders 
based  upon  the  presence  or  absence  of  a  functional  pygidium. 

The  Classification  here  followed  is  essentially  that  prepared  by  Beecher  for 
the  first  edition  of  this  treatise,  but  with  some  amplification  and  modification, 
made  possible  by  the  recent  work  of  Reed,  Clarke,  Jaekel,  Walcott  and  others. 
Beecher's  Classification,  although  not  universally  accepted,  has  proved  superior 
to  any  previously  proposed,  and  forms  the  basis  for  most  of  the  modern 
investigation  of  the  group. 


Order  1.     HYPOPARIA  Beecher. 

Free  cheeks  forming  a  continuous  marginal  ventral  plate  of  the  cephalon,  and  in 
sonie  forms  also  extending  over  the  dorsal  side  at  the  genal  angles.  Suture  ventral, 
marginal  or  submarginal.  Compound  paired  eyes  ahsent ;  simple  eyes  may  occur  on  each 
fixed  cheeJc,  singly  or  in  pairs. 

Even  in  the  higher  genera  of  this  order,  the  suture  is  frequently  unnoticed,  but  cau 
be  Seen  in  all  well-preserved  specimens.  In  Gryptolithus  and  Harpes  it  follows  the  edge 
of  the  cephalon,  and  separates  the  dorsal  from  the  ventral  plate  of  the  pitted  brim. 
Since  eye-spots  occur  on  the  fixed  cheeks  in  the  young  of  Gryptolithus  and  adult 
Harpes,  it  is  probable  that  this  character  is  a  primitive  one  in  the  order,  and  has 
been  lost  in  Agnostus,  Eodiscus,  Ampyx  and  Dionide. 

The  ontogeny  of  higher  genera  shows  that  the  true  eyes  and  free  cheeks  are  first 
developed  ventrally,  appearing  later  at  the  marginal,  and  then  on  the  dorsal  side  of 

this  respect,  a  very  primitive  head  structure,  characteristic  of  the  early  larval  forms 

of  higher  families.     Other  secondary  features  show  that  this  order,  though  the  most 

primitive  in  many  respects,  is  more  specialised  than  either  of  the  others,  except  in 

their  highest  genera.     The  characters  referred  to  are  the  glabella  and  pygidium.    Very 

few  species  show  the  primitive  segmentation  of  the  glabella,  it  being  usually  smooth 

and   inüated  and   resembling  in  its    specialisation   such    higher    genera  as  Proetus, 

W^Asaphus  and   Lichas.      The  pygidium   often   fails   to  indicate    its   true    number  of 

^■Segments.     Many  species  of  Agnostus  and  Eodiscus  show  no  segments  either  on  the 

Haxial  or  pleural  lobes  of  the  pygidium.     Gryptolithus  and  others  may  have  a  numerously 

^annulated  axis  and  fewer  grooves  on  the  pleural  portions.    The  number  of  appendages 

correspoiids  to  the  axial  divisions.     The  multiplication  of  segments  in  the  pygidium, 

and  their  consequent  crowding,  make  them  quite  rudimentary. 


Cei)hala  of  Ilypoparia.     A , 


Fio.  1357. 
Agnostun.     B,  Eodiscus.     C,  Harpes. 


D,  Cryptolithus.     E,  Ampyx  (after  Beecher). 


710 


ARTHROPODA 


PHYLUM  VTI 


Family  1.     Agnostidae  M'Coy. 

Hypoparia  with  head  and  ahdomen  shields  similar ;  free  cheeks  not  visihle  from  the 
dorsal  side.     Thorax  with  two  segments.     Cambrian  and  Ordovician. 

Subfamily  A.     Condylopyginae  Raymond. 

Agnostidae  with  many-lohed  shields,  long  glabella  which  expands  toward  the  front, 
and  long  and  hroad  axial  lohe  on  pygidium. 

Gondylopyge  Corda.  Anterior  lobe  of  glabella  broad.  Pygidium 
with  three  pairs  of  middle  -  lobes,  and  a  broad  end-lobe.  Middle 
Cambrian  ;  Europe  and  North  America. 

Pleurodenium  Corda  (Fig.  1358).  Similar  to  Gondylopyge,  but 
with  anterior  lobe  of  glabella  flattened,  and  crossed  by  radiating 
grooves.     Cambrian ;  Europe. 

Diplagnostus  Jaekel.  Anterior  middle-lobe  divided.  Axial  lobe 
of  pygidium  pointed  behind.     Cambrian  ;  Europe, 

Peronopsis  Corda.  Anterior  middle  lobe  of  glabella  simple,  not 
wider  than  the  part  behind.  Accessory  lobes  present  at  base  of 
granuiatum  (Barr.),   glabella.     Middle  Cambrian  ;  Europe  and  North  America. 

Cambrian  ;  Skrey, 
Bohemia.  ß/j  (after 
Barrande). 

Subfamily  B.     Arthrorachinae  Raymond. 

Agnostidae  with  middle   lohe  of  glahella   short   and   simple;  small   accessory  lohes 
present  at  läse  of  glahella. 

Arthrorachis  Corda.     Ordovician  ;  Europe  and  North  America. 
Hypagnostus  Jaekel.     Axial  lobe  of  pygidium  narrow,  pointed  behind. 


Fig.  1358. 
Pleurocteniw) 


Subfamily  C.     Agnostinae  Jaekel. 

Agnostidae  with  hoth  shields  sculptured.     Middle  lohe  of  cephalon   long,  narroived 
toward  the  front.     Accessory  lohes  always  present. 

Agnostus  Brongniart  (Figs.  1357,  A  ;  1359).  Surface 
smooth ;  accessory  lobes  simple.  Cambrian ;  Europe  and 
North  America. 

Ptychagnostus  Jaekel.  Surface  wrinkled  or  otherwise 
ornamented.  Accessory  lobes  double.  Cambrian ;  Europe 
and  North  America.  Fig.  1350. 

Agnostus   pisiformis  (Linn.). 
Cambrian  ;  Andrarum,  Svveden. 

Sabfamüy  D.     Phalacrominae  Corda.  ^S^ofur^'^S^ltZkAZ^i 

A  i-j  -,7     T  .  •■ ,  cephala  and  pygidia. 

Agnostidae  with  shields  scarcely  lohed. 

OrdSan'  Eiiro^;      ^'^'^^'    ^""^^   ""^   ''^^'^^''''    ^''^    pygidium    barely    indicated- 

Phalacrorm   Corda.      Cephalon    and  pygidium   without  lobes.       Cambrian   and 
üi-dovician  ;  Europe  and  North  America. 


Family  2.     Eodiscidae  Raymond. 

seameZ^ZllT^^  "T^  ^J'' f.'''^'  ''''  visihle  from  the  dorsal  ^de  ;  thorax  of  three 
Segments ,  pygidium  annulated.     Cambrian. 


SUBCLASS  I 


TEILOBITA ' 


711 


Eodiscus  Matthew  (Microdiscus  Salter  non  Emmons)  (Fig.  1357,  B).  Glabella  sliort, 
occipital  ring  spined.     Lower  and  Middle  Cambrian  ;  Europe  and  North  America. 

Goniodüc'us  Eaymond.  Glabella  long,  occipital  ring  obtusely  pointed.  Type, 
Microdiscus  lobatus  Hall.     Lower  Cambrian  ;  North  America. 


Family  3.     Shumardiidae  Lake,    ' 

Hypoparia  similar  to  the  Ägnostidae  in  size  and  in  structure  of  the  cephalon,  hut 
with  small,  strongly  segmented  pygidium,  and  six  segments  in  the  thorax. 

Shumardia  Billings.     Glabella  prominent,  expanding  toward  the  fi-ont.     Lower 
Ordovician  ;  Europe  and  North  America. 


Family  4.     Harpedidae  Corda. 

Hypoparia  with  very  large  head  shield  and  small  pygidium.  Free  cheeJcs  ventral, 
suture  marginal.  Thorax  with  numerous  segments  {seventeen  to  twenty-nine).  Cephalon 
loith  hroad  pitted  hrim.     Ordovician  to  Devonian. 

The  broad  hippocrepian  pitted  brim  of  the  Harpedidae  has  its  counterpart  in 
Cryptolithus  and  Dionide,  although  less  well  developed  in  those 
genera.  The  head  is  also  relatively  longer  and  larger,  both 
features  being  decidedly  larval.  The  functional  visual  spots  or 
ocelli,  situated  on  the  fixed  cheeks,  are  found  only  in  this 
family  and  in  Tretaspis  and  in  the  young  of  Cryptolithus.  The 
great  number  of  thoi'acic  segments  is  another  primitive 
character,  and  the  cephalon  is  larger  than  the  thorax  and 
pygidium. 

Harpes  Goldfuss  (Fig.  1357,  C).  Hypostoma  somewhat 
pentagonal,  angular  in  outline.  Silurian  and  Devonian  ; 
Europe  and  North  America. 

Eoharpes  Kaymond  (Harpina  Novak)  (Fig.  1360).  Hypostoma 
oval  in  outline.     Ordovician  ;  Europe  and  North  America. 


Flu.  1360. 


Koharpes  ungula  (Stern- 
berg). Ordovician  ; 
Bohemia.  l/i  (after  Bar- 
tande). 


Family  5.     Trinucleidae  Emmrich  (Cryptolithidae  Angelin). 

Hypoparia  with  large  cephalon  and  small  pygidium.  Free 
cheeks  ventral,  carrying  the  genal  spines.  Cephalon  with  a  pitted, 
brim.     Thoracic  segments  few  (ßve  or  six).     Ordovician. 

Cryptolithus  Green  {Trinucleiis  Murch.  pars)  (Figs.  1346, 1357, 
D;  1361).  Central  portion  of  cephalon  divided  by  the  dorsal 
furrows  into  three  prominent  portions.  No  ocelli  in  adult. 
Ordovician  ;  Europe  and  North  America. 

Trinucleus  Murch.  (restr.).     Glabella  obovate,  with  two  pairs 

of  weak  glabellar  furrows.      Pits  on  brim  set  in  deep  radiating 

furrows  ;  no  ocelli  or  eye-lines.     Ordovician  ;  Europe  and  North 

America.      Type  T.  fimhriatus  Murch. 

Glabella  spherical  in  front,  conical  behind,  with  two  pairs  of 

iye-lines   present.       Ordovician ;    Europe    and 


Fig.  1361. 
Cryptolithus        gohlfus.'^i 
(Barr.).  Ordovician  (Etage 
D) ;      Wesela,     Boliemia. 
xVi. 

Tretaspis  M'Coy. 
strong  glabellar   furrows  ;  ocelli   and 
North  America. 

Dionide  Barrande.     Similar  to  Cryptolithus,  but  with  an  irregularly  pitted  border 
and  a  large  pygidium.      Ordovician  ;  Europe. 


712 


K;imi 


ly6. 


ARTHROPODA 
Raphiophoridae  Angel 


PHYLUM  VII 


Fifi.  1362. 

Ampyx  nasutus 

(Dalmän).       Or- 

dovician ;      Pul- 

kowa,       Russia. 


Ampyx  portlocki  Barraiide. 
Ordovician  (Etage  D)  ;  Leiskow 
Bohemia.     x  Vi  (after  Bamuide). 


.  I.    7  u.'lnh,r1  cP,,halon  without  hrim,  small,  loide  pygidium,  and 

Hypoparia  wüh  Urgc  tnlohed  '^'V^^''^' T  ^^^^^^-^   ;^^,,,,,.      Small  free   cheeics 

visihle  on  the  dorsal  surface.  Glahella 
produced  in  front  of  the  cephalon  as  a  spme. 
Ordovician  and  Silurian. 

Raphiophorus  Angelin.  Glabella  obo- 
vate,  witli  an  abrupt  apical  spine.  Five 
thoracic  Segments.     Europe. 

Ampyx  Bsilm!xn{Yig>^.  1357,  i?;  1362, 
1363).  Glabella  oval,  terniinating  in  a 
round     spine.      Six     thoracic     Segments. 

^  Duu^iw.«.    ^   ,1V -     Europe  and  North  America. 

Lonchodomm  Angelin.  Glabellar  spine  long  and  prismatic  in  section.  Europe  and 
North  America. 

Order  2.     OPISTHOPARIA  Beecher. 

Free  cheeks  generally  separate,  always  hearing  the  geml  angles.  Fadal  sutnres 
e.tendingforwardfror.t}u  posterior  part  of  the  cephalon  ,mtMn  the  f-f»;f2bem 
cutting  m  anterior  margin  separately,  or  more  rarey  nmtmg  m  front  of  thegM^em, 
Compound  paired  holochroal  eyes  on  free  cheeks,  and  well  developed  rn  all  hnt  the  most 
primitive  family. 

The  families  which  are  here  placed  under  this  order  lend  themselves  quite  readily 
to  an  arrangement  based  upon  the  characters  successively  appearing  m  the  ontogeny  ot 
any  of  the  higher  forms.     Thus  Sao,  Ptychoparia  and  other  genera  of  the  Olenidae 


Fig.  1304. 

Cephala  of  the  Opisthojxiria.    A,  Atops.    B,  Conocwyphe.    C,  Ptychoparia.    D,  Olemis.     E,  Asa2-)hus. 

F,  lUaenus.    G,  Prwtus.    H,  Goldius.    I,  Lichas.    J,  Acidaspis  (after  Beecher). 

have  first  a  protaspis  8tage  only  comparable  in  the  structure  of  the  cephalon  with  the 
genera  of  the  preceding  order.  Therefore  this  stage  does  not  enter  into  consideration 
in  an  arrangement  of  the  families  of  the  Opisthoparia.  In  the  later  stages,  however, 
there  is  a  direct  agreement  of  structure  with  the  lower  genera  of  this  order.  The 
nepionic  Sao,  with  two  thoracic  Segments  (Fig.  1355,  B\  lias  a  liead  structure  agreeing 
in  essential  features  with  that  in  Atops  or  Gonocoryphe  (Figs.  1364,  A,  B).  A  later 
nepionic  stage,  with  eight  thoracic  Segments  (Fig.  1355,  G)  agrees  closely  with  the 
adult  Ptychoparia  or  Olenus  (Fig.  1364,  0,  D).  These  facts  clearly  indicate  that  the 
family  Conocoryphidae  should  be  put  at  the  base  of  this  extensive  order,  Moreover, 
as  Ptychoparia  Q.ndi  Olenus  are  more  primitive  and  simpler  genera  than  Sao,  they,  as 


SUBCLASS  I 


TRILOBITA 


713 


typifying  tlie  faniily  Oleiiidae,  govern  its  position,  which  accordiiigly  woiild  be  after 
the  Coiiocoryijliidae. 

Ditferences  in  tlie  position  of  the  eyes,  the  relative  size  of  the  free  and  fixed  cheeks, 
and  the  degree  of  specialisation  of  the  glabella  have  a  definite  order  in  the  ontogeny  of 
any  Trilobite,  and  furnish  characters  of  taxonomic  value  in  arranging  the  families 
placed  nnder  the  Opisthoparia  (see  Fig.  1364). 


Family  1.     Oonocoryphidae  Angelin. 

Opisthoparia  with  free  cheeks  very  narrow,  forming  the  lateral  margins  of  the 
cephalon,  and  hearing  the  genal  spines.  Eye-lines  are  present,  hut  neither  ocelli  nor 
Compound  eyes.  Thorax  ivith  from  fourteen  to  seventeen  segments.  Pygidium  small. 
Cambrian. 

The  genera  comprised  under  this  family  present  a  number  of  very  primitive 
characters,  such  as  are  displayed  only  in  the  larval  stages  of  higher  forms,  The  free 
cheeks  are  narrow  and  marginal,  and  may  be  compared  with  those  in  the  nepionic 
stages  of  Sao  and  Ptychoparia.  Eyes  have  not  been  detected,  but  the  presence  of  an 
eye-line  suggests  their  possible  existence.  The  variations  in  the  glabella  are  very 
marked,  and  are  as  great  as  those  which  in  higher  forms  attain  some  importance  as 
family  characteristics. 

So  far  as  known,  all  the  larval  forms  in  the  other  families  of  the  Opisthoparia 
agree  in  having  the  narrow  marginal  free 
cheeks,  bearing  the  genal  angles,  The 
eye-line  is  present  in  most  of  the  adult 
Olenidae,  and  in  the  early  stages  of  all  so 
far  as  known,  so  that  the  general  average 
of  characters  in  the  Oonocoryphidae  re- 
presents  the  main  larval  features  through- 
out  the  other  families. 

Conocoryphe  Oorda  (Figs.  1364,  B; 
1365,  1366).  The  glabella  is  convex, 
tapering  toward  the  front.  Anterior 
border  of  cephalon  marked  by  a  broad 
and  deep  furrow.  Oambrian  ;  Europe  and 
North  America. 

Ctenocephalus  Oorda.  Similar  to  Cono- 
coryphe, but  with  a  lobe  in  front  of  the 
glabella.  Oambrian ;  Europe  and  North 
America. 


Fio.  1365. 


Fig.  1367. 


Conocoryphe  sulzeri  Schloth. 
Without  the  free  cheeks.    Cam-  Cephalon  of>l /ojjs 

-,««.       ^       Toö^TN     t>rian      (Etage     C)  ;      Ginetz,        trilineatus  Em- 
Ätops  tjmmojis  (bigs.  13QA,  A;    13b 7).    Bohemia.    Vi-  "^o"«- 

Glabella  long,  and  does  not  taper.     Thorax 
of  seventeen  segments.     Pygidium  small.     Lower  Oambrian  ;  North  America. 


Family  2.     Mesonacidae  Walcott  {OlenelHdae  Moberg). 

Opisthoparia  with  large  cephalon  and  small,  simple  pygidium.  Facial  sutures  in 
a  State  of  Symphysis  and  usually  not  to  he  distinguished.  '  Eyes  large,  the  palpebral  lobes 
extending  to  the  glabella.  Glabella  narrow,  sometimes  tapering  toward  the  front. 
Thorax  of  numerous  segments  {thirteen  to  twenty-seven).     Lower  Cambrian. 

This  family  is  considered  by  "Walcott  to  have  developed  in  pre-Cambrian  time  from  sonie 
annelid-like  ancestor  by  the  gradual  combination  of  segments  to  form  the  ceplialon  and 
pygidium.  A  compact,  stroiig  pygidium,  made  up  of  raany  segments,  does  not  occur  in  this 
family,  nor  among  any  of  tlie  simplest  forms  of  Lower  Cambrian  Trilobites.     The  Middle 


714 


ARTHROPODA 


PHYLUM  YII 


Cambrian  Paradoxides  is  thought  to  have  been  descended  from  Callavia,  through  Ilolmia 
and  Wanneria. 

Mesonacis  Walcott.     Thorax  long  and  tapering,  tlie  tliird  segment  enlarged,  and 
tlie  pleura  extended  as  long  spines.     The  fifteenth  segment  has  a  large  spine  on  the 

axial  lobe.     Ten  segments  behind  the  great  spine. 
Europe  and  North  America. 

Elliptocephala  Emmons.  Like  Mesonacis,  but 
without  the  enlarged  third  segment,  and  with  long 
spines  on  the  axial  lobes  of  the  last  live  segments. 
Eastern  North  America.     E.  asaphoides  Emmons. 

Paedeumias  Walcott.  Like  Mesonacis,  but 
with  rudimentary  thoracic  segments  and  pygidium 
posterior  to  the  fifteenth  segment.  North  America. 
Olenellus  Hall.  Like  Mesonacis,  but  without 
segments  back  of  the  fifteenth,  the  great  spine  of 
which  is  iisually  considered  as  a  pygidium, 
Europe  and  North  America. 

Olenelloides  Peach.  Adult  is  essentially  like  a 
larval  form  of  Olenellus,  as  indicated  by  the  large 
cephalon  and  narrow  thorax.     Europe. 

Holmia  Matthew  (Fig.  1368).  Thorax  with 
sixteen  segments,  the  pleura  of  which  end  in 
rounded  spines.     Europe  and  America. 

_ ^ ^  Wanneria  Walcott.      Similar  to  Holmia,  but 

Ringsaker.Norway.    Lefriikif  öf  gTabeiia   with  broader  spines  on  the  pleura  of  the  thoracic 

romoved,  exposing  hypostoma  beneath.    3/.        j        -.t,  •  ^^        no,         ,i 

(after  Holm).      ^   '"■  ■   '^   Segments,  and  with  a  spme  on  the  fifteenth  seg- 

ment.    North  America. 
Callavia    Matthew.       Similar    to    Holmia,    but 
with   narrower  glabella,  and   broader  spines  on  the 
pleura     of    the    thoracic    segments.       Europe    and 
North  America. 

Peachella  Walcott.  Cephalon  with  blunt,  tumid 
genal  spines;  elongate,  narrow  glabella;  small  eyes 
and  marked  convexity.     Eastern  Nevada. 

Family  3.     Paradoxidae  Emmrich. 

Opisthoparia  with  large  cephalon,  small  free  cheeJcs, 
long  narrow  eyes,  the  palpehral  lohes  not  reaching 
the  glabella  in  the  adult.  Thorax  long,  with  numer- 
ous  segments  {seventeen  to  twenty- 
three).  Pygidium  small  and 
simple.     Cambrian. 

Paradoxides  Brongniart  (Figs. 
1369,  1370).  Glabella  enlarging 
toward  the  front.  Middle  Cam- 
brian ;  Europe,  Eastern  North 
America  and  Australia. 


Fig.  1368. 
Holmia  kjerulfi  Linnarson. 


Carabrian 


Fio.  1369. 
l'anuloxides   l)ohemi(yus    Barr.     Cam- 
bnan  (Etage  C);  Ginetz,  Bohen.ia.    i^,. 


Family  4.    Olenidae  Burmeister. 

Opisthoparia    with    short    and 
Wide    cephalon,    small    pygidium, 


Fig.  1370. 

Paradoxides  (cf. 
yoiing  of  P.  inßatns 
Cor  da)  =  Hydro- 
ccpludus  carens  Barr. 
Cambrian ;  Bohemia. 


SUBCLASR  I 


TRILOBITA 


71i 


small  free  cheeks,  and  narrovj  glahella.     Eye-lines  present,  eyes  small.      Thorax  of  from 
twelve  to  twentij-two  segments.     Cambrian  and  Ordovician, 

Olenus  Dalman  (Figs.  1364,  1) ;  1371).  Glabclla  only  inoderately  convex,  roimded 
in  front.      Upper  Cambrian  and  Ordovician  ;  Europe. 

Eurycare  Angelin  (Fig.  1372).  Cephalon  very  sbort  and  wide,  eyes  far  apart. 
Genal  spines  long  and  incurved.     Cambrian  ;  Europe, 


Fig.  1374. 

F^«-  13'1.  Fig.  1372.  Fio.  1373.  AulacopUuraTc<»vincU 

Olennstruncatus  Brunn.  Eurycare  brevicatida  Ang.  Sao  hirsuta  (Barr).  Barr.  Silurian  (Etage 
Cambrian  ;  Andrarum,  Cambrian  ;  Andrarum,  Sweden  Cambrian  (Etage  C)  ;  D) ;  Kuchelberg,  near 
Sweden  (after  Angelin).         (after  Angelin).  Skrey,  Bohemia.  Prague.     Bohemia. 


Peltura  Milne  Edwards.  Glabella  wide,  extending  neaiiy  to  tlie  'front  of  the 
cephalon.  Eyes  small,  close  to  tbe  front  of  tbe  glabella.  Pygidium  small,  witb  short 
spines.     Upper  Cambrian  ;  Europe  and  North  America. 

Ptychoparia  Corda  (Figs.  1348,  1364,  C).  Glabella  convex  and  narrow,  short, 
furrowed.     Pygidium  large.     Cambrian  ;  Europe,  Asia  and  North  America. 

Sao  Barrande  (Figs.  1349,  1354,  1355,  1373). 
Glabella  strongly  convex.  Thorax  of  seventeen  Seg- 
ments. Pygidium  very  small.  Surface  granulöse. 
Cambrian  ;  Bohemia. 

Euloma  Angelin.  Glabella  convex,  short,  with 
prominent  side  lobes,  similar  to  those  of  Calymene. 
Pygidium  short  and  wide.     Ordovician  ;  Europe. 

Aulacopleura  Corda  {Arethusina  Barrande)  (Fig. 
1374).  Glabella  short,  small,  with  basal  lobes.  Thorax 
öf  twenty-two  segments.  Pygidium  small.  Silurian ; 
Bohemia. 

Triarthrus  Green  (Figs.  1342,  1344-1345,  1350, 
1375).  Lacks  eye-lines.  Glabella  low  and  broad.  The 
facial  sutures  cut  the  genal  angles.  This  genus  is  note- 
wortliy  on  account  of  the  wealth  of  Information  that  has 
been  gained  concerning  the  appendages,  antennae  and 
other  parts  in  wonderfully  preserved  remains.  Ordovi- 
cian ;  Europe  and  America. 

Bathynotus  Hall.  Eyes  long  and  narrow.  Axial 
lobe  wide.  Thorax  of  thirteen  segments.  Lower  Cam- 
brian ;  America. 


Family  5. 


Fig.  1375. 

Triarthrus  becki  Green.  Ordo- 
vician ;  Rome,  New  York.  Specimen 
showing  antennae  and  ]>'<'<.  -''^ 
(after  Beecher). 


Solenopleuridae  Angelin. 

Opisthoparia    with    free    cheeks    small    and    widely 
separated    in    front,    glahella    short,    convex,    tapering    toivard    the    front,    eyes   small. 
Pygidium  short,  offeiv  segments.     Cambrian  and  Ordovician. 


716 


ARTHROPODA 


PHYLUM  VII 


Solenopl..a  Angelin.     Eyo-lincs  present.     Cambrian  ;  Europe,  Asia,  and  North 
^'" /Sri»,-«  EayB»nd,     Eye-line.  al«eut.     Onlovician  ;  North  America. 


Fig.  1376. 
Neolenus  serratAt.,  (Rominger).    Burgess  shale  (Middle  Cambrian) ;  Burgess  Pass  British  Columbia.    Posterior 
portion  of  an  individual  showing  thoracic  legs  and  caudal  rami.     x  ^/i  (after  Walcott). 

Family  6.     Oryctocephalidae 

Beeclier. 

Opisthoparia  with  large  cephalon 
and  smaller  pygidium,  palpehral  lohes 
long  and  connected  with  the  glahella. 
Pygidium  of  six  to  nine  Segments, 
which  end  in  spines.     Cambrian. 

Oryctocephalus  Walcott.  Glabellar 
furrows  represented  by  deep  pits  which 
are  connected  across  the  top  of  the 
glabella  by  shallow  furrows.  Middle 
Cambrian  ;  North  America  and  Asia. 

Zacanthoides  Walcott.  Glabellar 
furrows  not  deep,  intergenal  spines 
present,  thorax  spinöse.  Middle 
Cambrian  ;  North  America. 

Olenoides  Meek.  Pygidium  larger 
and  with  shorter  spines,  and  eyes 
smaller  than  in  Zacanthoides.  Cam- 
brian ;  America. 

Neolenus  Matthew  (Figs.  1343, 
1376,  1377).  Like  Olenoides,  bnt 
the  furrow  on   each   pleuron  of  the 

brian);  British  Columbia      Group  of  thoracic  and  abdominal    tliorax    is   diagonal    instead    of    being 
Iftirs.  showiiit?  basal  mint  or  r.nxonoditft.  and  siv.in  r,fo,i  i,.r,  o       ^      ^^'^'  ^^  O 


Fio.  13Y7. 
Neolenus  serratits  (Rominger).     Burgess  shale  (Middle  Cam- 


legs,  showing  basal  Joint  or  coxopodite,  and  six-iointod  1 
with  three  terminal  claws.     x  Vi  (alter  Walcott>! 


straight.      Cambrian ;  America. 


SUBCLASS  I 


TRILOBITA 


717 


Fig.  1378. 

Alhertella  helenae  Walcott.     Lower  Cambrian 
Powell  County,  Montana  (after  Walcott). 


Family  7.     Ceratopygidae  Raymond. 

Ojnsthoparia  ivüh  suh-equal  cephalon  and  pygidium,  long,  nearly  smooth  glahella. 
Pygidium  with  long  spines  at  the  sides.     Caiuljrian  and  Ordovician. 

Geratopyge  Corda.  Glabella  long,  narrow,  with  basal  lobes.  Pygidium  with  long 
spines  springing  from  the  pleural  lobes  at  the  second  annulation.  Basal  Ordovician ; 
Euro2)e  and  North  America. 

Alhertella  Walcott  (Fig.  1378).  Eyes  long,  glabella  with 
three  pairs  of  furrows.  Pleura  of  third  segraent  of  thorax 
extended  into  spines.     Cambrian  ;  North  America  and  Asia. 


Family  8.     Ellipsoce- 
phalidae    Matthew. 

Ojjisthoparia  with 
narrow  free  cheeJcs,  small 
eyes,  smooth,  imfurroioed 
glahella,  twelve  to  sixteen 
thoracic  Segments,  and  small 
pygidium.     Cambrian. 

Ellipsocephal'us  Zenker 
(Fig.  1379).  Dorsal  fur- 
rows of  the  cephalon  deep, 
cheeks  are  very  narrow. 
Cephalon  with  a  narrow, 
raised  border.  Cambrian  ; 
Europe  and  North 
America. 

Agraulos  Corda. 
Glabella  faintly  outlined, 
cephalon  without  concave 
or  rimmed  border.  Cam- 
brian; Europe  and 
America. 

Strenuella  Matthew.     Similar  to  Agraulos,  but  with  a  narrow 
cephalon.     Lower  Cambrian  ;  America. 


Fig.  1379. 

Ellipsoceplialus  hoffi 
Schloth.  Cambrian 
(Etage  C)  ;  Ginetz, 
Bohemia. 


Fig.  1380. 

Caphyra radians 
Barr.  Ordovician 
(Etage  D) ;  Königshof, 
Bohemia.  i/i  (after 
Barrande). 

riin  around  the 


Family  9.     Remopleuridae    Corda. 

Opisthoparia  with  large,  faintly  furrowed  glahella,  ivhich  has  a  tongue-like  anterior 
ptrojection.  Eyes  very  large,  extending  nearly  around  the  glahella.  Thorax  of  eleven  to 
thirteen  segments.     Pygidium  small.     Ordovician. 

Remopleurides  Portlock,  Pygidium  wider  than  long,  with  two  pairs  of  short 
spines.      Ordovician  ;  Europe  and  America. 

Gaphijra  Barrande  (Fig.  1380).  Pygidium  long  and  flat.  Genal  spines  and 
pleura  of  thorax  flattened.     Ordovician  ;  Europe  and  North  America. 


Family  10.     Bathyuridae    Walcott. 

Opisthoparia  with  cephalon  and  pygidium  usually  nearly  eqiial  in  size.  Glahella 
long,  cylindrical,  reaching  nearly  to  the  anterior  margin.  Eyes  large  and  dose  to  the 
glahella.  Tliorax  of  nine  segments.  Pygidium  more  or  less  strongly  rihhed.  Middle 
Cambrian  to  Ordovician. 


18 


ARTHROPODA 


PHYLUM  VII 


Bathyurus  Billings  (Fig.   1381). 


Fkj.  1381. 

Ikithyunis  longispinus  Walcott. 
(Oi(iovician)  ;    Newport,  N.Y. 
Raymond). 


Black  River 
X    Vx  (after 


Glabellar  fiirrows  faint  or  absent.  Pygidium 
witli  four  pairs  of  smootli  ribs,  and  a  long^  pro- 
minent axial  lobe.  Ordovician  ;  North  America, 
including  Beekmantown  beds  of  Newfoundland. 

Petigurus  Raymond.  Cephalon  like  Bath- 
yurus. Pygidium  witli  nodose  ribs  and  strongly 
annulated  axial  lobe,  Ordovician  ;  Canada  and 
Ireland. 

Bathyuriscus  Meek.  Glabellar  furrows 
deeper,  eyes  further  forward,  and  pygidium 
larger  than  in  Bathyurus.  Middle  Cambrian  ; 
North  America  and  Asia. 

Bathyurellus  Billings.  Glabella  low,  smooth, 
pointed  in  front.  Cephalon  and  pygidium 
witli  broad  concave  borders.  Ordovician  ;  North 
America. 

Family  11.     Asaphidae    Burmeister.         ■ 

Opisthoparia  with  large,  suh-cqual  head  and 
ahdomen  shields,  prominent  eyes,  eight  segments  in 
the  thorax,  and  with  a  median  vertical  suture  in 
the  doublure  of  the  cephalon.  Middle  Cambrian 
to  Ordovician. 


Subfamily  A.     Ogygiocarinae  Raymond. 

Asaphidae  with  hypostoma  rounded  or  pointed  hehind. 

Ogygiocaris  Angelin  {Ogygia  auct.  non  Brong.)  (Fig.  1339).     Pygidium  with  flat, 
furrowed  ribs.     Axial  lobe  very  narrow.     Facial  suture 
marginal  in  front  of 
glabella.  Ordovician  ; 
Europe, 

Ogygopsis  Wal- 
cott (Fig.  1382). 
Similar  to  Ogygio- 
caris, but  with  eye- 
lines,  and  eyes  small 
and  far  apart.  Middle 
Cambrian  ;  British 
Columbia. 

,  Megalaspis  Ange- 
lin (Fig.  1383). 
Glabella  short, 
cephalon  and  pygi- 
dium nearly  smooth 
and  sometimes 
pointed.  The  facial 
sutures  meet  in  a 
point  far  forward  of 
the  glabella.  Ordovi- 
cian ;  Europe,  Asia, 
and  rarely  North 
America. 


Fig.  1382 


Fig.  1383. 

Megalaspis  extenuata  Ang.  Ordo- 
vician ;  Eäst  Gotland,  Sweden. 
Vi  (after  Angelin). 


SUBCLASS  I 


TRILOBITA 


719 


Äsaphellus  Callaway.  Similar  to  Megalaspis,  but  with  loiiger  and  flatter  glabella, 
and  shorter  sbields.      Treniadoc ;  Europe.      Lower  Ordovician  ;  Nortli  America. 

Hemigyraspis  Eaymond.  Similar  to  Äsaphellus^  but  witli  facial  sutiire  marginal 
in  front.     Tremadoc  ;  Eiiroi^e.     Lower  Ordovician  ;  North  America. 

Symphysurus  Goldfuss.  Cephalon  and  pygidium  short,  sub-hemisplierical,  without 
concave  border.     Axial  lobe  narrow.     Lower  Ordovician  ;  Europe  and  America. 

Nileus  Dalman.  Similar  to  Symphysurus,  but  with  broad  axial  lobe  and  very 
large  eyes.     Ordovician  ;  Europe  and  North  America. 


Subfamily  B.     Asaphinae    Raymond. 
Asaphidae  with  hypostoma  bifurcated. 
Äsaphus  Brongniart  (Figs.  1364,  E ;  1384).     Cephalon  and  pygidium  short  and 


Fig.  1384. 
Asaphus  expansus  (Linn.).    Ordovician  ;  Pulkowa,  near  St.  Petersburg,  Russia.    i/i  (after  Salter). 

wide,  glabella  prominent,  expanding  forward,  and  reaching 
the  anterior  margin,  which  is  without  concave  border. 
Axial  lobe  of  pygidium  ringed,  pleural  lobes  smooth. 
Ordovician  ;  Europe  and  Asia. 

Onchometopus  Schmidt.  Similar  to  Asaphus^  but  the 
glabella  only  obscurely  defined,  axial  lobe  rather  wide,  and 
pygidium  smooth.    Ordovician ;  Europe  and  North  America. 

Basüicus  Salter.  Pygidium  strongly  ribbed,  glabella 
convex,  prominent,  facial  suture  marginal  in  front.  Ordo- 
vician ;  Europe  and  North  America. 

Ogygites  Tromelin  and  Lebesconte  {Ogygia  Brongniart) 
(Fig.  1385).  Similar  to  Basüicus,  but  glabella  less  pro- 
minent, and  sutures  meeting  in  a  point  in  front  of  glabella. 
Ordovician  ;  Europe  and  North  America. 

Ptychopyge  Angelin.  Glabella  short,  facial  sutures  well 
inside  the  margin,  pygidium  not  ribbed,  concave  borders 
wide,  and  doublure  very  broad.     Ordovician  ;  Europe. 

Isotelus  Dekay.  Cephalon  and  pygidium  smooth,  with 
wide  depressed  borders.  Axial  lobe  of  thorax  wide.  Ordo- 
vician ;  rare  in  Europe,  abundant  in  North  America. 

Family  12.     lUaenidae    Corda. 

Opisthoparia  with  large,  convex  cephalic  and  abdominal 
shields  which  are  nearly  smooth  and  without  concave  border. 
Epistomal  plate  large,  hypostoma  convex,  ovoid.  Thorax  of 
eight  to  ten  segmeiits,  with  smooth  pleura.     Pygidium  smooth,  Fcc  13S5. 

with  short  axial  lobe.     Ordovician  and  Silurian.  Ogypitcs    guettanU    (Hrong.). 

Ordovician  ;     An^«'rs,     France. 

Illaenus  Dalman  (Figs.   1364,  F ;  1386).      Axial  lobe   SrJÄBroSrt).  ""'" 


720 


ARTHROPODA 


PHYLUM  VII 


aboiit  one-tliird  tlie  total  widtli.      Ordovician  and  Silurian  ;  Europe,  Asia  and  North 
America. 

A  n  r 


Fk;.  13.S(i. 

A,  lJ!'"'ny'<  'Iii'itiifniYolh.  Ordovician;  Pull<:owa,  near 
St.  PctiTsbur-,  liussiu.  B,  C,  I.  crassicauda  Dalman. 
Ordovician  ;  J)alck;uiieii,  Sweden  (after  Holm). 


Bumastus  Murcliison.    Axial  lobe  very  wide ;  ceplialon 


and  j^ygidiiim  smooth. 
and  North  America. 
Thaleofs  Conrad, 
small  and  elevated. 
America. 


Ordovician  and  Silurian ;  Europe 


Glabella  rather  well  defined 


Fig.  13b7. 

•j  Dikelocephalus    minnesotensis 

Ordovician  and  Silurian  ;  North  Owen.  Upper  Cambrian ;  Wiscon- 
sin. A,  Cranidiuni,  B,  Pygidiuni 
(after  Hall). 


Family  13.     Dikelocephalidae    Miller. 

Opisthoparia  with  large  cephalon  and  pygidium,  glahella  marked  by  faint  furrows 
which  extend  across  it.  Eyes  large.  Pygidium  with  short  axial  lohe,  and  usually  a 
pair  offlat  spines.     Upper  Cambrian  and  Lower  Ordovician. 

Dikelocephalus  Owen  (Fig.  1387).  Spines  on  pygidium  far  apart,  short  and 
broad.  Complete  specimens  are  known  of  D.  Mensis  and  D.  crassimarginatus. 
Upper  Öambrian  ;  North  America. 

Dikelocephalina  Brögger.  Spines  close  together  at  the  posterior  end  of  pygidium. 
Lower  Ordovician ;  Europe. 


Family  14.     Goldiidae  Raymond  {Bronteidae  Angelini). 

Opisthoparia    with  eyes  close  to  the  glahella  and   to   the  posterior  margin  of  the 
cephalon.     Glahella    much    expanded    toward    the   front.      Thorax    with    ten    segments 
Pygidium  larger  than  the  cephalon,  with  short  axial  lohe.     Ordovician  to  Devonian. 
Goldius  de  Koninck  {Brontes  Goldfuss)  (Figs.  1340,  1364,  H ;   1388).     Pygidiuni 

with  radiating  ribs  extending  from  the  end 
of  the  axial  lobe  to  the  margin.  Ordovician 
to  Devonian;  Europe  and  America. 

Thysanopeltis  Corda.  Like  Goldius,  but 
with  small  spines  along  the  posterior  margin 
of  the  pygidium.  Devonian;  Europe  and 
North  America. 

Bronteopsis  Nicholson  and  Etheridge. 
Cephalon     like     Goldius;      pygidium     with 

tudinal  ridge.      The  ribs  on  the  r^uJTfl  ^""f ^  ^''^''  ^^^'""^  "^^'^'^  ^'  ^  ^^^^S^" 
li".li..s  tl.at  tl,o  latter  appellatto'n  wasprroccupreS  =*'"*"*"ä  '"  ^••~'«  "'  t^e  Same  author  „„ 


Fig.  1388. 

'/"  (13eyr).    Cephalon.    Devonian 

U't.  i-,,  Konieprus,  Bohemia  (after  Banande). 


SUBCLASS  I 


TRILOBITA 


21 


Fig.  1389. 
Froetus  hohemicus  Corda. 


Pic.  1390. 

Philli'pina  gemimdifera 
Phill.    Lower  Carboni- 


Family  15.     Proetidae    Corda. 

Small  Opisthoparia  ivith  cephalon  and  pygidium  nearly  equal,  free  cheeJcs  large,  eyes 
long,  and  dose  to  the  glahella.  Thorax  with  eight  to  ten  segments.  Ordovician  to 
Permian. 

Proetus  Steiiiinger  (Figs.  1351,   1364,  G;   1389).     Glabella  witliout  deep  lateral 
furrows.    Pygidium  smaller  tlian  cephalon. 
Ordovician     to     Carboniferous ;     Europe, 
Asia  and  America. 

Gyphaspü  Burmeister.  Similar  to 
Proetus,  biit  with  a  strongly  elevated 
ridge  which  surrounds  the  glabella  out- 
side  the  dorsal  furrows.  Glabella  with 
prominent  basal  lobes.  Ordovician  to 
Devonian  ;  Europe  and  America. 

Haploconus  Raymond.  Similar  to 
Gyphaspis,  but  without  the  basal  lobes  on 
the  glabella.  Type,  Bathyurus  smithi 
Billings.     Ordovician  ;  North  America. 

PhilUpsia      Portlock      (Fig.      1390). 
Similar  to  Proetus,  but  with  large  pygi- 
dium,  and  tosal  lobes  on  glabella.     This   KÄt?r*ÄXr'      fS" '  ■""""■   '"^ 
genus    survived  all    other   trilobites,   but 

became    extinct    with    the    close    of    the    Permian.      Carboniferous    and    Permian ; 
Europe  and  America. 

Family  16.     Aeglinidae  Pictet. 

Opüthoparia  with  large  glahella  and  eyes  which  occupy  nearly  the  whole  area  of  the 
free  cheeks. 

This  genus  has  the  glabella  strongly  convex, 
prominent,  smooth  ;  fixed  cheeks  suppressed  ; 
eyes  very  large  ;  thoracic  segments  five  or  six  ; 
pleura  grooved  ;  pygidium  large,  with  short  axis, 
Ordovician  ;  Europe. 

Family  17.     Lichadidae    Corda. 

Opisthoparia  with  large  cephalon  and  pygi- 
dium, the  glahella  greatly  modified  hy  the  peculiar 
development  of  the  lateral  furrows.  Thorax  with 
nine  or  ten  segments.  Pygidium  with  short 
axial  lohe,  and  the  pleural  lobes  modified  in 
various  ivays.     Oixlovician  to  Devonian. 

Lichas  Dalman  (Figs.  1364,  7;  1392). 
The  glabella  is  broad,  with  axial  furrows  which 
do  not  reach  the  neck  furrow.  Occipital  lobes  are  present.  Pygidium  flat,  with 
the  pleural  lobes  divided  by  furrows  into  two  pairs  of  lobes  with  short  free  ends,  and 
a  median  flattened  lobe.     Ordovician  and  Silurian  ;  Europe  and  America. 

Amphilichas  Raymond  {Platymetopus  Schmidt).  Glabella  large,  divided  longi- 
tudinally  into  three  lobes  by  a  pair  of  axial  furrows  which  jom  the  neck  ring. 
Ordovician  ;  Europe  and  America.  r  .,   i  , 

Gorydocephalus  Corda  {¥i^.  1338,^  ;  1393).    GlabeUa  with  three  pairs  of  side  lobes, 

VOL.  I  ^  ^ 


Äeglina  Barrande  (Fig.    1391). 

A  n  0 


Fio,  1391. 
Aefilitia  prisca  Barr.     Ordovician  (Etage  D)  ; 


Vosek,  Bohemia 
(after  Barrande), 


A,  Nat.  size.     7.',  ü,  enlarged 


722 


ARTHROPODA 


PHYLÜM  VII 


tlie  central  lobe  narrow. 


Fia.  1392. 

Lii-Iins  laciniatus 
Siluriaii ;  Sweden 
Angeliii). 


Wahlb. 
(after 


13!  »3. 


Corydocephul  us  pti/onurufi 
Hall  and  Clarke.  Silurian  ; 
New  York. 


Pygidium  small,  tlie  pleural  lobes  crossed  by  two  narrow, 
prominent  ribs  which  end  in  spines. 
Ordovician  and  Silurian ;  Europe 
and  Nortli  America. 

Hoplolichas  Dames  (Fig.  1394). 
Ceplialon  trilobed,  the  central  lobe 
produced  in  front,  and  not  depressed 
at  the  back  as  in  GonoUchas.  Occipital 
lobes  present.  Ordovician  to  De- 
vonian  ;  Europe. 

Geratarges  Gürich  (Fig.  1395). 
Glabella  witli  two  curved  spines  in 
front,  and  pygidium  with  numerous 
spines.     Devonian ;  Europe. 

Geratolichas  Hall  and  Clarke 
(Fig.  1396).  Ceplialon  with  two 
pairs  of  long,  curved  spines  on  the 
axial  portion.  Devonian ;  North 
America. 

Terataspis  Hall.  Glabella  bulbous, 
strongly pustulose.  Devonian;  North 
America. 


Fig.  1395. 

Ceratarges  armatus 
(Goldfuss).  Devonian  ; 
Germany  (after  Beyrich). 


Fio,  1394, 


Hoplolichas  schmidti  Dames. 
Ordovician ;  Germany  (after 
Dames). 


Fig.  1396. 

Geratolichas  gryps  Hall 
and  Clarke.  Devonian ;  New 
York  (after  Hall  and  Clarke). 


Family  18.     Odontopleuridae 
Burmeister. 


twelve  Segments.      Pygidium  small. 
Ordovician  to  Devonian. 


Opisthoparia      lüith      large     free 
cheeks,  small  eyes.      Thorax  of  eight  to 
All  parts  of  the  crust  are  usually  very  spinöse. 


In  this  family,  as  well  as  in  the  Lichadidae,  is  to 
be  found  the  highest  expression  of  difFerentiation  and 
specialisation  among  the  Opisthoparia.  The  primitive 
pentamerous  lobation  of  the  axis  of  the  cranidium  is 
entirely  obscured,  and  is  only  clearly  seen  in  the  pro- 
taspis  and  early  nepionic  stages.  These  two  families 
are  very  closely  related,  the  chief  differences  being 
noted  m  the  size  and  character  of  the  pygidium,  and 
the  ribbed  or  grooved  pleura.  The  Lichades  are 
generally  much  larger  and  flatter,  but  the  smaller  and 
spmose  forms  of  Geratarges  and  Geratolichas  approach 
quite  near  some  of  the  Acidaspidae. 

^  Odontopleura  Emmrich.  Occipital  ring  smooth  or 
with  a  median  tubercle.  Ordovician  and  Silurian- 
Europe  and  America.  ' 

Ascidaspis  Murchison  (Figs.  1352  1364  j) 
Occipital  ring  with  a  Single  median  spine.'  Ordovician 
and  Silurian  ;  Europe  and  America. 

Geratocephala  Warder  (Fig.  1397).  Occipital  ring 
with  two  long  nearly  straight,  divergent  spines 
Ordovician  and  Silurian  ;  Europe  and  North  America 


Fig.  1397. 

Geratocephala  dufrenoyi  (Barr. ).  Sil- 
urian (Etage  E) ;  St.  Ivan,  Bohemia 
(after  Barrande). 


I 


SÜBCLASS  I 


TRILOBITA 


723 


r 

K  Äncryopyge  Clarke.     Margin  of  pygidium  with  twelve  very  long,  slender,  curved 

B:  spines.     Devonian  ;  North  America. 

H  Selenopeltis  Corda.     Thorax  with  very  long  spines  extending  from  the  pleura  ; 

B  pygidium  aspinose.      Ordovician ;  Europe. 

B  Glaphurus  Raymond.     Thorax  witli  twelve  Segments.     Pygidium  very  small  and 

B  aspinose.     Ordovician  ;  North  America. 

Order  3.     PROPARIA  Beecher. 

Free  cheehs  not  hearing  the  genal  angles.  Facial  sutures  extending  from  the  lateral 
margins  of  the  cephalon  in  front  of  the  genal  angles,  inward  and  forward,  cutting  the 
anterior  margin  separately,  or  uniting  in  front  of  the  glahella.  Compound  paired  eyes 
scarcely  developed  or  sometimes  ahsent  in  the  most  primitive  family ;  ivell  developed  and 
schizochroal  in  the  highest  family. 

This  is  the  only  order  of  Trilobites  which  apparently  begins  during  the  known 
Paleozoic,  and  unlike  the  other  Orders,  had  no  pre-Cambrian  existence.     The  earliest 


Pio.  1398. 

Cephala  of  the  Proparia.     A,  Placopai'ia.     B,  Encrinurus.     C,  Calymene.    D,  Dipleura.    E,  Cheirurus. 
F,  Dahnanitina.     G,  Dalmanites.    H,  Chasmops,    I,  Phacopidella.    J,  Phacops  (after  Beecher). 

forms  of  Proparia  were  initiated  at  the  close  of  the  Cambrian  and  dawn  of  the 
Ordovician.  The  greatest  generic  differentiation  of  the  group  was  early  attained  ; 
during  the  Silurian  and  Devonian  a  rapid  decline  ensued,  and  only  one  or  two 
genera  survived  into  the  beginning  of  the  Carboniferous. 

Among  the  Opisthoparia,  it  seems  clear  that  the  Conocoryphidae  formed  the 
natural  base  or  most  primitive  family  in  the  order,  and  is  distinguished  by  the 
narrow  marginal  free  cheeks  and  absence  of  well-developed  eyes.  It  is  of  great 
interest  and  importance  to  be  able  to  note  that  und  er  the  Proparia  there  is  a  similar 
primitive  family  having  characters  in  common  with  the  other,  but  still  clearly 
belonging  to  the  higher  order.  Placoparia,  Areia  and  Dindymene  constitute  a  group 
of  apparently  blind  Trilobites  with  narrow  marginal  free  cheeks,  and  present  in 
general  the  appearance  of  Atops,  Gonocoryphe,  Gtenocephalus,  and  other  members  of  the 
Conocoryphidae. 

Family  1.     Encrinuridae  Angelin. 

Proparia  with  narrow  free  cheeks ;  either  blind^  or  ivith  small  eyes.  Pygidium 
composed  of  many  segments,  the  pleural  ribs  usually  less  in  numher  than  the  rings  on  the 
axial  lohe,  and  usually  ending  in  spines.     Ordovician  and  Silurian. 

Encrinurus  Emmrich  {Oromus  Barrande)  (Figs.  1338,  B,  G ;  1398,  B  ;  1399,  1400). 
Cephalon  tuberculated,  glabella  prominent,  free  cheeks  separated  in  front  by  a  small 


ARTHROPODA 


PHYLUM  VII 

fl  K'  I    1-1  ri.i  ;  r  \  /  i^xi. 

724 

,     1  .  .    cn.n    elevated   on    conical  promineiices ;    tlioracic  segmentB 

epistomal  plate ;    eyes   small,  «levatedj^^^  _  ^^^.^.F^^^  ^^^^^^^^^^  triangulär.     Ordo- 

viciaii  and  Silurian  ;  Europe,  Asia,  and  America. 

Gyhele  Loven.     Similar  to  Encnnurus,  but 

with  the  ribs   of  the   pygidium   turning  back 

sliarply,  parallel  to  the  axis.     Ordovician  and 

,,     ,,,,  Silurian ;  Europe  and  America.  J 

Fi(i.  1400.  "M 

Fio.  13l»li.  Encrinurns  hohemicus  ^ 

Encrinurus   punc     (liarrande).   Silurian     p     ii„  £.     Calymenidae    Miliie  Edwards, 

taiTEmmrich.'^Sil-       (Etege  E) ;  Lochkow.       i^amiiy  ^.  y  ,      ,,        , 

urian ;  Qotiand.  Bohemia.  Proparia  wüh    tUrteen    Segments,  the   hypo- 

aoma  notched  bekind,  and  attached   to  an  ^AümM  plate.      Free  cheeks  narro^,  the 
facial    sutures    cutting    the 
margin    almost    exactly-\in 
the  genal  angles.    Oi^dovician 
to  Devonian. 

Galymene  Brongniart 
(Figs.  1398,  0;  1401). 
Glabella  prominent,  strongly 
lobed,  with  two  or  three 
pairs  of  lateral  furrows. 
Ordovician  to  Devonian ; 
Europe,  Asia  and  America. 

Pharostoma  Corda. 
Glabella  prominent,  very  narrow  at  the  front,  with 

two  pairs  of  glabellar  furrows.     Long  genal  spines 

present.     Ordovician;  Europe. 

Homalonotus  Koenig.    Axial  lobe  wide,  cephalon 

Short  and  trilobate  in  front,  cheeks  forming  high 

mounds  crowned  by  the  eyes.      Silurian;    Europe 

and  Nova  Scotia. 

Trimerus  Green  (Fig.   1402).     Cephalon  longer 

than  in  the  preceding,  not  trilobate  in  front,  free 

cheeks  narrow.     Silurian  and  Devonian  ;  world-wide 

distribution. 

Dipleura  Green  (Fig.  1 3  9  8,  D).     Axial  lobe  wide. 

Pygidium  smooth.    Devonian  ;  Europe  and  America. 

Family  3.     Cheiruridae  Salter.  Fig.  1402. 

Trimerus  delphinocephalus  Green. 
Propana  with  small  free  cheeks,  whose  anterior  ends  ■         Silurian ;  Lockport,  New  York. 

are  separated  hy  the  glabella.     Pygidium  small  with 

pleura  ending  in  spines.     Thorax  with  nine  to  eighteen  Segments.     Ordovician  to  Devonian. 


Fig.  1401. 

Galymene    meeU     Foerste. 
Ordovician ;  Cincinnati,  Ohio. 

X  Vi- 


Subfamily  A.     Cheirurinae   Raymond. 

Cheiruridae  with  eleven  segments  in  the  thorax  {rarely  nine  to  thirteen),  and  four 
Segments  in  the  pygidium. 

Gheirurus  Beyrich  (Figs.  1398,  E  ;  1403).  Glabella  smooth,  more  than  one-third 
the  total  width  of  the  cephalon  ;  pygidium  with  six  or  seven  sub-equal  spines. 
Ordovician  and  Silurian ;  Europe,  Australia  and  America. 

Geraurus  Green  (Fig.  1341).  Glabella  pustulose,  one-third  or  less  the  total  width 
of  the  cephalon  ;  pygidium  very  small,  with  the  first  pair  of  spines  very  long,  the 
others  short  or  absent.     Ordovician  ;  Europe,  Asia,  and  America. 


SUBCLASS  I 


TRILOBITA 


725 


Grotaloceplialus    Salter.      Siinilar    to    Gheirurus  but  witli  furrows  extending   all 
across  the  glabella.     Silurian  and  Devonian  ;  Europe. 

Sphaerexochus  Beyrich.  (Fig.  1404).     Glabella  globular,  cheeks  small.     Ordovician 

and  Silurian  ;  Europe  and  America. 
Pseudosphaerexochus  Schmidt. 
Glabella  tumid,  tapering  forward. 
Pygidium  with  subequal  spines. 
Ordovician  ;    Europe  and  America. 

Nieszkowshia  Schmidt.  Glabella 
tumid  or  prolonged  into  a  spine 
behind.  Pygidium  with  two  pairs  of 
spines.  Ordovician  ;  Europe  and 
America. 


Fig.  1403. 

Cheirurus  insignis  Beyr.  Sil- 
urian (Etage  E);  Kozolup,  Bo- 
hemia.     i/i  (after  Bairande). 


Fig.  1404. 

Sphaerexochus  mirus 
Beyrich.  Silurian; 
Listice,  Bohemia.  x  Vi 
(after  Barrande). 


Fig.  1405. 

Cephalon  of  Pliomera  fischeri 
(Eichwald).  Ordovician  ;  Pulkowa, 
Russia. 


Subfamily  B.     Pliomerinae  Raymond. 

Gheiruridae  with  fifteen  to  nineteen  segments  in  the  thorax ;  pygidium  hemispheric, 
with  five  ßat  segments. 

Pliomera  Angelin  (Ämphion  Pander)  (Fig.  1405).  Glabella  expanding  forward, 
with  two  small  median  lobes  on  the  front.  Border  of  the  cephalon  denticulate. 
Ordovician  ;  Europe. 

Pliomerops  Raymond.  Similar  to  Pliomera^  but  the  glabella  has  parallel  sides, 
and  lacks  the  two  small  lobes  at  the  front.     Oi-dovician  ;  Europe  and  America. 

Placoparia  Corda  (Fig.  1398,  A).  Free  cheeks  are  narrow ;  eyes  absent. 
Ordovician  ;  Europe. 

Subfamily  C.     Deiphoninae  Raymond. 

Gheiruridae  with  a  part  of  the  glabella  bulbous. 

Beiphon  Barrande.  (Fig.  1406).  Glabella  globular, 
without  lateral  furrows.  Free  cheeks  minute.  Silurian  ; 
Europe  and  North  America. 

Staurocephalus  Barrande.  Glabella  with  two  pairs 
of  glabellar  lobes  behind  the  bulbous  portion.  Cephalon 
with  a  denticulate  border,  and  pygidium  similar  to  that 
of  Pliomera.     Silurian  ;  Europe  and  North  America. 

Sphaerocoryphe  Angelin.  Glabella  with  one  pair  of 
lobes  behind  the  bulbous  portion.  Ordovician  and 
Silurian  ;  Europe  and  North  America. 


Deiphon  forhesi 
(Etage  E)  ;  St. 
(after  Barrande). 


Silurian 
Bohemia 


with  large  facets,  schizochroal. 


Family  4.     Phacopidae  Corda. 

Proparia    ivifh    rather    large  free    cheeks,  eyes  large. 
Thorax  with  eleven  segments.     Ordovician  to  Devonian. 


726 


ARTHROPODA 


PHYLUM  VII 


Subfamily  A.     Dalmanitinae  Reed. 

Phacopidae  with  more  or  less  modified  pentamerous  segmentation  of  the  glahella,  and 

usually  lüith  large  cranidia  and  pygidia. 

Dalmanitina  Reed  (Figs.  1353;  1356; 
1398,  i'^;  1407).  Pentamerism  of  head  well 
marked,  lobes  of  glabella  distinct ;  genal  angles 
rounded  or  with  short  spines.  Pygidiiim 
with  few  Segments,  rarely  more  thaii  ten. 
Ordovician  and 
Silurian  ;  Europe. 

Dalmanües  Bar- 
raude  (Figs.  1337  ; 
1398,  G-,  1408). 
Frontal  lobe  of  gla- 
bella detached.  Pygi- 
dium  strongly  mucro- 
nate,  with  twelve  to 
Devonian ;    Europe    and 


Dalmanitina  socialis  (Barr.).     Ordovici? 
D);  Wesela,  near  Prague,  Bohemia.    Cephalon, 


Silurian    and 


sixteen    segments. 
America. 

Asteropyge  Corda  {Cryphaeus  Green).  Pygidium  with  five 
pairs  of  marginal  spines,  and  sometimes  a  terminal  spine. 
Devonian  ;  Europe  and  America. 

Proholium  (Ehlert.  Cephalon  with  a  snout-like  anterior 
Prolongation.     Devonian  ;  Europe  and  America. 


Subfamily  B.     Phacopinae  Reed. 

Phacopidae  with  glahellar  furrows  nearly  or  quite  o 
and  pygidium  small  and  rounded. 


Fig.  1408. 

Dalmanües  limulurus 
(Green).  Silurian ;  Lockport, 
New  York  (after  Hall). 


Phacopidella  Reed  (Acaste  Goldfuss)  (Figs.  1398, 1;   1409). 
Glabella  with    three    pairs  of  ^.^^^^^^         faintly     defined     lateral      furrows. 

Ordovician      and       Silurian ;       J^W^^^      Europe. 

Phacops    Emmrich     (Figs.     ijjflfg^^ 
furrows,     except     occasionally   P  J^j^^gpl  the    last    pair,    obsolete.      Silurian 
and    Devonian  ;     world  -  wide  fe'^  wkgmM^M  distribution. 


Fio.  1409, 

Phacopidella  dovmingiae 
(Murch.).  Silurian  ;  Lud- 
low,  England  (after  Salter). 


Fig.  1410., 

Phacops  latifrons 
Bronn.  Devonian  ; 

Gerolstein,       Eifel 
üistrict,  Germany, 


Fig.  1411. 

Phacops  sternbergi  Barr. 
Devonian  (Etage  G)  ;  Hostin. 
Bohemia  (after  Barrande). 


Trimerocephalus  M'Coy.     Eyes  small  and  far  forward.     Devonian  ;  Europe. 


^fplg. 


süBCLASs  I  TRILOBITA  V27 

Subfamily  C.     Ptp^rygometopinae  Reed. 

Rather  small  Phacopidae,    the  cephalon   with  more   or    less  modißed  ijentamerous 
lohation,  and  the  pygidium  less  triangulär  and  with  fewer  Seg- 
ments than  in  most  of  the  Dalmanitinae. 

Pterygometopus  Schmidt  (Fig.  1412).  Glabella  with  three 
pairs  of  lateral  furrows,  Ordovician ;  Europe  and  North 
America. 

Chasmops  M'Coy  (Fig.  1398,  H).     Second  pair  of  glabellar  ^'''-  ^^^^• 

lobes  absent,  or  represented  by  tubercles.     Ordovician  ;  Europe.   (DS.r'''oJ^i'ovfSrrf  • 

MonoraJcos  Schmidt.  Second  and  third  pairs  of  glabellar  iswos,  Esthonia  (after 
furrows  represented  by  pits.     Ordovician  ;  Europe.  ^  ™' 

Geological  Range  and  Distribution  of  Trilobites. 

Trilobites  are  the  only  large  division  of  the  Arthropoda  which  has  become  extinct. 
Even  in  the  earliest  Cambrian  they  bear  evidence  of  great  antiquity, — in  their 
diversified  form,  larval  modifications,  polymerous  head  and  caudal  shields.  These 
features  show  that  Trilobite  phylogeny  must  extend  far  back  into  pre-Cambrian 
times,  and  it  is  probable  that  primitive  Branchiopods,  of  a  type  corresponding  to  the 
modern  Äpus,  were  developed  even  earlier.  The  views  of  Bernard  and  Walcott 
regarding  the  origin  of  Trilobites  and  higher  Crustacea  from  a  primitive  Apus-like 
ancestral  stock  are  mentioned  a  few  pages  farther  on  under  the  head  of  Branchiopoda. 

Concerning  the  habits  of  Cambrian  Trilobites  Dr.  Walcott  has  suggested  that  the 
adult  animals  probably  crawled  about  the  sea-bottom  and  did  not  swim  freely  in  the 
water  to  the  extent  that  it  would  be  necessaiy  to  see  the  bottom.  Their  habits  must 
have  been  very  much  like  those  of  Limnlus  when  in  search  of  food.  That  the 
creatures  burrowed  and  pushed  their  way  through  the  mud  and  soft  sands  is  proven 
by  the  trails  and  burrows  made  by  them,  some  of  which  we  now  designate  as 
Protichnites. 

The  maximum  development  of  Trilobites  occurred  in  the  Cambrian  and  Ordovician, 
after  which  they  steadily  waned  both  in  numbers  and  variety.  The  genera  of  the 
Conocoryphidae,  Eodiscidae,  Mesonacidae,  Paradoxidae,  Oryctocephalidae  and  Ellipso- 
cephalidae,  are  wholly  restricted  to  the  Cambrian,  and  here  also  are  found  nearly  all 
the  Olenidae  and  Agnostidae,  only  scattering  representatives  of  which  survive  into 
the  Ordovician.  The  Asaphidae  are  more  characteristic  of  the  Ordovician,  and  the 
Cryptolithidae,  Shumardiidae,  Remopleuridae,  Bathyuridae  and  Aeglinidae  are 
restricted  to  it.  The  Raphiophoridae,  Goldiidae,  Harpedidae,  Encrinuridae,  and 
Illaenidae  flourished  in  the  Ordovician  and  Silurian,  while  the  Proetidae,  Lichadidae, 
Odontopleuridae  and  Phacopidae  attained  their  greatest  development  in  the  Silurian 
and  Lower  and  Middle  Devonian. 

The  later  Devonian  witnesses  a  decline  in  the  number  of  families  present,  and  with 
the  close  of  this  era,  the  class  practically  became  extinct,  since  only  five  genera  of 
one  family,  the  Proetidae,  are  met  with  in  the  Carboniferous,  and  the  single  genus 
Phillipsia  alone  persists  as  late  as  the  Permian. 

As  regards  their  geographica!  distribution,  some  genera  are  of  cosmopolitan  occur- 
rence :  such  as  Ägnostus,  Conocoryphe,  Ptychoparia,  Paradoxides,  Gryptolithus,  Illaenus, 
Proetus,  Phillipsia,  Äcidaspis,  Lichas,  Calymene,  Homalonotus,  Cheirurus,  Phacops, 
Dalmanites,  and  others.  The  majority  of  forms,  however,  are  extremely  limited  in 
distribution,  so  that  a  large  number  of  genera  found  in  Sweden,  Bohemia,  England 
and  North  America  are  unknown  outside  of  cerUiin  very  restricted  areas  ;  and  the 
total  number  of  species  common  to  both  sides  of  the  Atlantic  is  very  small. 

A  remarkable  contrast  is  observable  between  the  older  Paleozoic  Trilobites  of  the 


728 


ARTHROPODA 


PHYLÜM  VII 


northern  parts  of  Europe,  and  tliose  of  tlie  middle  and  soutliern  portions.  Wliile  the 
niajority  of  northern  genera  and  si^ecies  are  common  to  Great  Britain,  Scandinavia 
and  Russia,  the  forms  of  the  central  European  provinces  (Bohemia,  Thuringia,  Fichtel- 
berg, the  Hartz,  Belgium,  Brittany,  Northern  Spain,  Portugal,  the  Pyrenees;  the  Alps 
and  Sardinia)  are  so  dissimilar  as  to  stand  in  closer  relationships  with  the  North 
American  than  with  the  first-named  Trilobite  fauna.  Of  the  350  species  found  in 
Norway  and  Sweden,  and  of  the  275  species  in  Bohemia,  only  six  are  common  to 
hoth  provinces,  and  it  is  doubtful  if  these  are  really  identical. 

The  first  of  the  accompanying  tables  shows  the  ränge  and  relative  development  of 
the  Orders  and  the  subclass ;  the  second  represents  the  vertical  ränge  of  the  several 
families  of  Trilobites. 

TABLE   I 

Diagram  Constructed  by  Beecher  showing  Relative  Development 
OF  THE  Orders  of  Trilobites 


[Table 


SUBCLASS  I 


TRILOBITA 


729 


Table  showing  Vertical  Range  of  Trilobites 


Orders  and  Families. 


?  C   i  -O  t: 


Order  1.  Hypoparia 

Family  1.  Agnostidae  . 

2.  Eodiscidae  . 

3.  Shumardiidae 

4.  Harpedidae 

5.  Trinucleidae 

6.  Raphiophcrridae 

Order  2.  Opisthoparia 

Family  1.  Conocoryphidae 

2.  Mesonacidae 

3.  Paradoxidae 

4.  Olenidae 

5.  Solenopleuridae 

6.  Oryctocephalidae 

7.  Ceratopygidae 

8.  Ellipsocephalidae 

9.  Remopleuridae 

10.  Bathyuridae 

11.  Asapliidae    . 

12.  lUaenidae     . 

13.  Dikelocephalidae 

14.  Goldiidae     . 

15.  Proetidae     . 

16.  Aeglinidae  . 

17.  Lichadidae  . 

18.  Odontopleuridae 

Order  3.  Proparia 

Family  1.  Encrinuridae 

2.  Calymenidae 

3.  Cheiruridae 

4.  Phacopidae  . 


Total  Number  of  Famili 


8    il  22      11 


3    '    1 


[The  foregoing  cliapter  oii  Trilobites  has  been  revised  by  Dr.  Percy  E.  Raymond,  of  the 
Museum  of  Comj)arativc  Zoology  at  Cambridge,  Mass.  Some  notes  on  Cambrian  genera, 
togetlier  witli  two  or  three  figures  illustrating  the  same,  have  been  contributed  by  Dr.  C.  D. 
Walcott.  —Editor.  ] 


730 


ARTHROPODA 


PHYLUM  VII 


Subclass  B.    EUCRUSTACEA  Kingsley/     (Crustacea  proper.) 

Crustacea  having  typically  two  pairs  of  antenniform  preoral  appendages  and  at 
hast  three  pairs  of  postoral  appendages  acting  as  jaws. 

In  the  Crustacea  proper  the  appendages  of  the  head-region  are  as  follows : 
the  first  and  second  pairs  are  preoral  and  are  known  respectively  as  antennules 
and  antennae ;  the  third  pair,  placed  on  either  side  of  the  mouth,  are  the 
mandibles;  the  fourth  pair,  maxillulae,  and  fifth  pair,  maxillae  (the  two  pairs 
sometimes  known  as  first  and  second  maxillae),  are  secondary  jaws.  The 
appendages  behind  these  vary  in  character,  some  being  Walking  or  swimming 
feet,  while  from  one  to  three  pairs  may  be  subsidiary  to  the  maxillae  in 
feeding,  in  which  case  they  are  called  maxillipeds. 

Regarding  the  evolution  of  the  subclass,  Bernard  has  reached  the  conclusion 


I 


1 


Strabops   ■ 


Sidneyia  •  • 


Agiaspis 
Mobria 


Emeraldella'-  . 
Habelia 


y 


NathorsUa 


•Mauella 


Bidentia 


-Hymenocaris 


,  Opabin 


Beltina^ 


Theoeetical  Evolution  of  Cambrian  Crustacea  from  the  Branchiopoda 
(accordmg  to  Walcott  2). 

ilT'firü^Z""*'"^  are  descended  from  a  browdng  carnivorous  annelid  with 

md!  n  L  "ir;"^  ?  PÜ-T'"*  ^°'  P"^*^'"«  f°°d  into  its  mouth.  The 
Be.trd  TZf'^'r  .i'^'^'^^'P'''''^*'"^'  crustacean-annelid,  according  to 
fauna  otß  itÄ,„    W    ^'   ^"«ess  shale   (Middle   Oambriän)    crustalan 

whTh  have  the  L  Hh  \T'  "'"*'"  *"'"^"<^^'  ^^'  ^''»«^  W«^«  Walcott, 
Wh  ch  have  the  head  bent  down  so  that  the  mouth  faces  posteriorly,  and  in 

Literature:  Öerstoec^-er,  yi.  and  Ortoj«««   a    v   n      ^  ■    ^        , 

des  Thierreichs,  vol.  v.,  1866-1901  — rl/T  w/  m'  ^^^«^^^ea,  in  Bronn's  Klassen  und  Ordnungen 
pt.  vii.,  fasc.  3,  1909.  '     ^""'^^»  '^-  ^^  Crustacea,  in  Lankester's  Treatise  on  Zoology, 

Smithson!  mL^oU.',  1912!'voLTvi[!^no.^r'^'''^°'^^'  ^^^^«««t^^««'  Trilobita,  and  Merostomata. 


J 


süBCLASs  II  EUCRUSTACEA— BRANCHIOPODA  731 

the  opiiiioii  of  bheir  describer  may  have  been  derived  from  the  same  general 
type  of  animal  as  the  accompanying  crustaceans. 

The  preceding  diagram,  which  is  taken  from  Walcott,  illustrates  that 
author's  views  as  to  the  relations  of  Cambrian  crustaceans  to  a  theoretical 
ancestral  stock  which  for  convenience  is  correlated  with  ^^'ws-like  forms. 
From  this  primitive  stock  it  is  assumed  that  the  Branchiopoda  were  derived, 
and  from  them  three  distinct  branches  were  developed  prior  to,  or  diiring, 
Cambrian  time.  According  to  this  view  Trilobita  are  direct  descendants  of 
Branchiopoda,  and  in  turn  gave  rise  to  the  line  leading  through  the  Orders 
Aglaspina,  Limulava  and  Eurypterida  to  the  Xiphosura.  The  structure  and 
probable  habits  of  Trilobites  lead  Walcott  to  the  opinion  that  these  w^re 
mud-burrowing  animals  more  or  less  allied  to  Limulus.  The  Phyllocarida 
and  Ostracoda  are  assumed  by  the  same  author  to  have  been  derived  from 
the  Branchiopoda,  but  on  different  lines  of  descent  from  that  of  the  Trilobites 
and  the  Orders  grouped  under  the  Merostomata. 

The  Eucrustacea  are  frequently  divided  into  Entomostraca  and  Malacostraca^ 
but  the  first  of  these  groups  is  not  a  homogeneous  assemblage ;  it  is  rather  a 
repository  in  which  have  been  placed  all  forms  not  members  of  the  Malacostraca. 
The  Eucrustacea  are  here  divided  into  the  superorders  Branchiopoda,  Ostracoda^ 
Copepoda,  Cirripedia  and  Malacostraca. 

Superorder  1.    BRANCHIOPODA  Latreille.i 

Eucrustacea  in  which  the  carapace  may  form  a  dorsal  shield  or  a  bivalve  shell  or 
may  he  entirely  ahsent ;  the  number  of  body  segments  and  appendages  varies  greatly  ; 
the  appendages  of  the  body  are  rarely  pediform,  generally  foliaceous  and  lobed. 

Under  the  Branchiopods  are  embraced  very  differently  formed  Crustaceans 
of  large  and  small  size,  living  mostly  in  fresh  water  or  salt  lakes,  and 
possessing  little  eise  in  common  than  the  leaf-like  form  of  leg.  The 
segmentation  of  the  body  in  the  larger  forms  is  very  distinct,  but  in.  the 
water  fleas  (Cladocera)  it  is  usually  quite  incomplete.  The  number  of  body- 
segments  varies  considerably  among  different  genera.  In  the  strongly 
segmented  forms  the  body  is  elongated  and  protected  in  front  by  a  flat  or 
shield-shaped  dorsal  carapace  (Apus),  or  it  is  naked  (Branchipus),  In  the 
Cladocera  and  Estheriidae,  which  are  enclosed  in  a  bivalve  shell,  the  body  is 

^  Literat ure  :  A.  Recent  Forms. — Grube  E..,  Bemerkungen  über  die  Phyllopoden,  etc.  Wieg- 
mann's  Archiv  für  Naturgesch.,  1853-1865,  vols.  xix.,  xxi. — Claus,  C,  Papers  ou  Branchipus 
and  Apus,  in  Abhandl.  Gesellsch.  Wiss,  Göttingen,  1873,  vol.  xviii.,  and  Arbeit.  Zool.  Inst,  Wien, 
1886,  vol.  vi.  —  Weismann,  F.  L.  A.,  Zur  Naturgeschichte  der  Daphniden.  Zeitschr.  Wissensch. 
Zool.,  1876-80,  vols.  xxvii.,  xxxiii. — Lankester,  JE.  R.,  Several  papers  on  Limulus,  Apus,  etc., 
in  Quart.  Journ.  Microsc.  Soc,  1881,  vol.  xxi. — Packard,  A.  S.,  Monograph  of  the  Phyllopod 
Crustacea  of  North  America,  12th  Ann.  Rept.  U.S.  Geogr.  and  Geol.  Surv.  Terr.,  1883.— Äirs,  G.  0., 
Fauna  Norvegiae.  I.  Phyllocarida  and  Phyllopoda,  1896. — Bernard,  H.  M.,  The  Apodidae.  Nature 
series,  London,  1892. 

B.  Fossil  Forms. — Jones,  T.  R.,  On  Fossil  Estheriae  and  their  distribution.  Quar.  Journ. 
Geol.  Soc,  1863,  vol.  xix.— Monograph  of  the  Fossil  Estheriae.  Palaeontogr.  Soc,  1862.— 5th 
and  7th  Repts.  Comm.  British  Assoc  Adv.  Sei.  on  Fossil  Phyllopoda,  1887-89.— Geol.  Mag., 
Sept.  1890,  Feb.  1891,  Dec  1893,  July  1894.— Trans.  Geol.  Soc.  Glasgow,  1890,  vol.  ix.— 
Glarke,  J,  M.,  New  Devonian  Phyllopods.  Amer.  Journ.  Sei.,  1882,  vol.  xxiii. — Hall,  J.,  and 
Glarke,  J.  M.,  Palaeontology  of  New  York,  1888,  vol.  viu—Bemard,  IL  M.,  Fossil  Apodidae. 
Nat.  Sei.,  1897,  vol.  xx.—Schuchert,  C.,  On  the  fossil  Phyllopod  genera  Dipeltis  and  Protocaris. 
Proc.  U.S.  Nat.  Mus.,  1897,  vol.  xix.—Clarke,  J.  M.,  Estheria  in  Devonian  of  New  York  and 
Carboniferous  of  Ohio.  Rept,  N.Y.  State  Paleontologist,  1900.— 7</eH(,  Notes  on  Paleozoic  Crus- 
taceans. 54th  Ann.  Rept.  N.Y.  State  Mus.,  1902,  vol.  \.— Walcott,  C.  D.,  Middle  Cambrian 
Branchiopoda,  Malacostraca,  etc.     Smithson  Mise.  Coli.,  1912,  vol.  Ivii.,  no.  6. 


732 


ARTHKOPODA 


PHYLUM  VII 


laterally  compressed,  shortened,  and  often  indistinctly  segmented.  The  head 
is  sharply  demarcated  from  the  rest  of  the  body,  and  is  usually  provided  with 
two  large  eyes  sometimes  coalesced,  in  addition  to  which  there  is  often  a 
a  small  unpaired  eye.  The  Upper  lip  is  very  large,  the  mandibles  have  no 
palps,  and  the  maxillae  are  reduced  or  absent. 

The  body-limbs  are  usually  foliaceous  and  lobed  on  the  outer  and  inner 
margins.  They  vary  in  number  from  four  to  more  than  sixty  pairs,  and 
usually  all  carry  gill-plates.  The  posterior  part  of  the  body  is  without 
limbs  and  usually  ends  in  a  caudal  furca,  the  rami  of  which  may  be  filiform, 
flattened  or  claw-like.  All  Branchiopods  have  the  sexes  ^distinct.  The 
males  are  often  much  less  numerous  than  the  females,  and  the  latter 
reproduce  largely  by  parthenogenesis. 

The  Classification  of  the  Branchiopoda  here  given  diff'ers  from  that 
commonly  adopted,  in  that  the  term  Fhyllopoda  (Latreille,  1802)  is  not 
employed  for  an  ordinal  division  including  several  groups  which  are  dis- 
tinguished  from  the  Cladocera  chiefly  by  the  greater  number  of  somites  and 
appendages  and  by  the  prevalence  of  metamorphosis  in  development.  Tnstead, 
these  groups  of  the  old  division  Phyllopoda  are  more  properly  assigned  the 
rank  of  independent  Orders,  all  three  being  sharply  contrasted  from  one 
another  as  well  as  from  a  fourth  order,  Cladocera.  Phyllopods  in  the  old 
sense,  therefore,  are  equivalent  to  the  Orders  Anostraca,  Notostraca  and 
Conchostraca,  as  here  recognised.  The  Substitution  of  the  term  Phyllopoda 
for  Branchiopoda,  in  the  usage  of  Claus  and  some  writers  following  him  is 
contrary  to  the  rule.^ 

Order  1.     ANOSTRACA  Sars. 

Head    distinct,   carapace  ahsent,  paired   eyes  pedunculate ;    thorax  with   eleven   to 
nineteen  pairs  of  trunJc-Umhs,  none  post  -  genital ;  furcal   rami_ 
unsegmented,  rod-lihe  or  flattened. 

Branchipodites  Woodward.  Similar  to  the  Recent  BrancU- 
pus.  Oligocene  of  Bembridge,  Isle  of  Wight.  B.  vectensis 
Woodw. 

Opahinia^  Leanchoilia,  Yohoia  (Fig.  1413),  Bidentia  Walcott. 
Middle  Cambrian  ;  British  Columbia. 

Order  2.     NOTOSTRACA  Sars. 

Carapace  forming  a  dorsal  shield  ex- 
tending  over  the  anterior  segments  ;  paired 
eyes  sessile ;  antennae  vestigial ;  trunk- 
limhs  forty  to  sixty-three  pairs,  of  ivhich 
twenty-nine  to  fifty-two  are  post-genital  ; 
furcal  rami  multiarticulate. 

Protocans  Walcott  (Fig.  1414).     This 
is  the  oldest  representative  of  the  Apus- 
type,  and  exhibits  a  remaikable  similarity 
to  Apus  in  its  univalve  carapace,  multi- 
,  segmented   abdomen,  and   sinj^le  pair  of 

caudal  spmes.     Lower  Cambrian  ;  Vermont. 

Mlopoda,  applj.n,  11,,.  1.  tte      o  the  superorder  and  the  former  to  one  of  its  divisions,  but  this 
1'}  priority  or  by  universal  custom. 


Pio.  1413. 
Yohoia   tenuis   Walcott 
Middle  Cambriaii  ;  I5i  itisl 
Columbia.      Dorsal    viiw 
X2/i. 


use  is  not  sanctioned  citli 


Fig.  1414. 

Frotocaris  marshi 
Lower  Cambrian  ; 
Vermont,    x  2/3. 


^ 


SUBCLASS  II 


EUCEUSTACEA— BRANCHIOPODA 


'33 


Riheiria  Sliarpe  ;  Ribeirella  Shubert  and  Waagen.  These  names  have  been  applied 
to  arched,  univalved  bodies  with  strong  beaks,  muscular  scars  and  sub-cardinal  ridge. 
They  occur  in  tlie  eaiiy  Ordovician  of  Europe  and  America,  and  are  doubtfully 
assigned  to  a  position  among  tlie  Apodidae. 

Apus  Latreille.  Trias  to  Recent.  Lepidurus  Leach.  Recent.  These  genera, 
incliided  in  the  family  Apodidae,  comprise  the  largest  known  forms  of  Branchiopods, 
some  species  of  Apus  having  a  length  of  70  mm.  The  under-mentioned  Cambrian 
Notostracans  are  placed  in  separate  families  by  Walcott. 

Naraoia  (Fig.  1415),  Burgessia  and  JVaptia  Walcott  (Fig.  1416).  Middle 
Cambrian  ;  British  Columbia. 

Änomalocaris    Whiteaves.     This    name    has    been    applied    to    bodies    from    the 


Fig.  1415. 

Narctoia  compacta  Walcott.     Middle  Cambrian  ; 
British  Columbia.     Dorsal  view,  x  2/,. 


Fio.  1416. 

Waptia  fieldensis  Wal- 
cott. Middle  Cambrian ; 
British  Columbia.  Dorsal 
view  of  flattened  specimen, 
X  Vi- 


Cambrian  of  British  Columbia  which  have  been  compared  to  the  segmented  abdomen 
of  a  Branchiopod,  each  segment  bearing  a  pair  of  lamellate  appendages.  Although 
the  objects  abound  where  found,  nothing  is  known  of  the  carapace,  nor  is  there  any 
evidence  of  the  surface  markings  which  characterise  most  Crustacean  shields.  Their 
affin ities  are  doubtful. 

Euchasma,  Eopteria  and  Ischyrina  Billings ;  Technophorus  Miller.  These  names 
have  been  applied  to  remains  from  the  Ordovician  of  North  America,  regarded  by 
their  describers  as  Pelecypods,  but  undoubtedly  of  Crustacean  nature.  Their  reference 
to  the  Notostraca  is  uncertain. 


Orders.     CONCHOSTRACA  Sars. 

Carapace  hivalved,  enclodng  the  whole  hody ;  antennae  well  developed,  hiramous^ 
natatory ;  paired  eyes  sessile,  coalescent  Body-limbs  ten  to  twenty-seven  pairs,  of  which 
none  to  sixteen  are  post-genital,  and  thefirst  one  or  two  in  the  male  form  clasping  organs. 
Furcal  rami  claw-like. 


734 


ARTHROPODA 


PHYLUM  VII 


Family  1.     Limnadiidae  Baird. 
Family  characters  the  same  as  ahove  given  for  the  order. 

Estheria  Riippel  (Figs.  1417,  1418).     Shell  composed  of  two  tliin  rounded  valves, 
united  by  a  straiglit   tootliless  margin.     External  surface  concentrically  ridged  or 


FlG 


Estheria  minuta  Alberti.  Lettenkohle  Dolo- 
mite ;  Sinsheim,  Baden.  A,  Vi-  -B»  ^/i-  <?> 
Portion  of  the  exterior,  50/j. 


Fig.  141S. 

Estheria  sp.  indet.  Lower  barren 
Goal  Measures  ;  CarroUton,  Ohio. 
Umbonal  portion  showing  muscular 
or  nuclear  node,  13/^. 


striated,  and  between  the  ridges  are  more  or  less  regularly  interlacing  or  branching 
Striae.  The  latter  character  serves  to  distingiiish  this  geniis  from  Posidonomya  among 
Pelecypods.  The  beaks  are  not  sharply  defined,  and  the  primitive  portions  sometimes 
bear  a  strong  ocular  or  muscular  node. 

The  genus  Estheria  has  numerous  fossil  representatives,  being  first  met  with  in  the 
Devonian,  and  occurring  mostly  in  brackish  and  shore  deposits.  It  abounds  in  the 
productive  Goal  Measures,  in  the  Permian,  Trias  (Lettenkohlen mergel)  and  Wealden, 
and  has  been  found  in  the  Pleistocene  clays  of  Canada. 

Leaia   Jones    (Fig.    1419).     Carapace   marked    by  one  or    two    diagonal    ridges 


Fig.  1419. 
A,  Leaixi  leidyi  Jones.   Goal  Measures ;  Pottsville, 
Pennsylvania.    B,  Uaia  Inentschiana  Geinitz.    Goai 
Measures;  Neunkirchen,  near  Saarbrücken  (after 
Golden  berg). 


Fig.  1420. 

Schizodiscus  capsa  Glarke. 
Hamilton  ;  Centerfield,  New 
York.     2/j. 


whicb  ran  from  the  anterior  end  of  the  dorsal  margin  toward  the  lower  margin. 
Carboniferous  ;  Europe  and  North  America. 

Estheriella  Weiss.      Carapace  as  in  Estheria,  but  with   radial  riblets  crossing  the 
concentric  Striae.     Permian  ;  Russia.     Buntersandstein  ;  Saxony 
_    _  Schizodiscus  Clarke  (Fig.  1420).     Carapace  peltate,  with  a  straiglit  hinge  which 
18  in  the  major  axis  of  the  shield.     Fach  valve  nearly  a  semicircle  ;  surface  marked 
with  concentric  ridges.     Middle  Devonian  ;  New  York. 

Lepeditta  Matthew.     Cambrian  ;  North  America. 


SÜBCLASS  II 


EUCRUSTACEA— OSTRACODA 


735 


Family  2.     Bradoriidae  Matthew. 

Garapace  bivalved,  memhranaceous^  calcareo-corneus  in  composüio^i,  not  completely 
separated  hut  prohahly  often  fused  aloncj  the  cardinal  edge ;  free  margins  of  valves 
slightly  gaping ;  main  muscle  spot  dose  to  antero-cardinal  angle  just  hehind  and  beneath 
the  ocular  tuhercle. 

The  niembers  of  this  family  have  hitherto  been  considered  as  Cambrian  Ostracoda,  but 
recent  studies  have  shown  them  to  be  Branchiopoda.  The  genera  listed  below  embrace 
several  distinct  types  of  structure,  and  will  in  part  be  referred  to  other  families  in  the  course 
of  study. 

Beyrichona  Matthew  (Fig.  1421,  A,  B).  Valves  subtriangiilar  with  a  broad 
undefined  depression  in  the  dorsal  slope,  limited  in  front  by  a  short  node-like  ridge. 


Fig.  1421. 

A,  Beyrichona  tinea  Jfatthew.  x  Vi-  -ß' 
Beyrichona  papilio  Matthew.  x  ■^/i.  Middle 
Cambrian  of  New  Brunswick. 


Fig.  1422. 

A,    Hipponicharion   clavatum   Matthew. 

X  4/i-     -B,   ^luta   enyo  (Walcott).      x  8/j. 

Middle  Cambrian  of  New  Brunswick  and 

China. 


Hipponicharion    Matthew    (Fig.     1422,    A).      Valves    semi-elliptical    with    two 
prominent  marginal  ridges  and  an  inconspicuous  central  ridge  near  hinge  line. 

Polyphyma  Groom.     Valves  semicircular  with  numerous  rather  variable  tubercules. 
Bradoria^  Escasona,  Aluta  Matthew  (Fig.  1422,  B).     (?)  Isoxys  Walcott. 


Order  4.     CLADOCERA  Müne  Edwards. 

Garapace  hivalved,  generally  enclosing  hody  hut  leaving  headfree  ;  paired  eyes  sessile, 
coalesced  ;  antennae  large,  forming  swimming  organs ;  four  to  six  pairs  of  body-limhs ; 
furcal  rami  claw-like. 

The  egg-cases  (ephippia)  of  Cladocera  have  been  recognised  in  Glacial  deposits  in 
Germany.  Lynceites  ornatus  Goldenberg,  from  the  Carboniferous,  is  a  very  doubtful 
representative  of  this  order. 

Superorder  2.     COPEPODA  Milne  Edwards. 

Eucrustacea  without  a  distinct  carapace,  but  with  one  or  two  of  the  anterior 
somites  coalesced  with  the  head.  Paired  eyes  usually  ahsent.  Antennules  anU 
antennae  usually  well  developed ;  typicalhj  six  pairs  of  biramons  body-limhs.  Caudal 
furca  present. 

The  Copepoda  are  without  knovvn  representatives  in  the  fossil  State. 


Superorder  3.     OSTRACODA  Latreille.i 

Small,  indistinctly  segmented  Crustacea  completely  enclosed  in  a  horuy  or  calcareoiis 
bivalve  shell.     Not  more  than  seven  pairs  of  appendages  present — two  of  antennae, 

^  Literature  :    Bosquet,   J.,   Description  des  Eutoniostraces  fossiles  de  la  craie  de  Maestrich t. 


736  ARTHKOPODA  phylum  vii 

one  of  mandibles,  two  of  maxillae,  and  two  pairs  of  feet.  Abdomen  short  and 
riLdimentary. 

As  a  ruie  only  the  bivalved  shell  of  the.Ostracoda  is  found  fossil,  and  since 
the  Classification  is  based  principally  upon  characters  presented  by  the 
appendages,  the  relations  of  recent  to  fossil  forms  cannot  be  made  out  with 
certainty,  especially  as  the  form  and  ornamentation  of  the  shell  are  largely 
independent  of  the  internal  Organisation. 

The  valves  are  closed  by  a  subcentral  adductor  muscle,  the  attachment  of 
which  is  marked  on  their  inner  sides  by  a  tubercle,  pit,  or  a  number  of  small 
spots.  The  shell  is  compact  in  structure,  commonly  from  0*5  mm.  to  4  mm. 
in  length,  although  sometimes  exceeding  20  mm.  The  outer  surface  may  be 
smooth  and  glossy,  or  granulöse,  pitted,  reticulose,  striate,  hirsute,  or  other- 
wise  marked,  the  effect  being  often  quite  ornamental.  The  two  valves  may 
be  of  equal  size  (Beyrichia),  or  more  or  less  unequal,  with  either  the  right  or 
left  valve  overlapping  at  the  ventral  border  only  (Leperditia),  or  at  the  dorsal 
border  as  well  (Bairdia),  or  in  some  cases  overlapping  all  round  (Cytherella). 

Most  commonly  the  outline  is  ovate  or  reniform ;  in  many  cases,  however, 
one  or  both  ends  may  be  pointed  or  drawn  out  in  the  form  of  a  beak ;  and 
when  the  dorsum  is  straight,  the  ends  may  join  it  angularly.  Although 
usually  convex,  the  ventral  margin  is  sometimes  straight  or  gently  concave. 
It  is  sometimes  impossible  to  distinguish  between  anterior  and  posterior 
extremities,  but  as  a  rule  the  posterior  half  is  somewhat  thicker  than  the 
anterior,  even  though  of  equal  or  of  less  height.  The  hinge -line  may  be 
straight  or  arcuate,  the  hinge  itself  being  generally  simple,  although  among 
the  Cytheridae  hinge  teeth  and  corresponding  sockets  are  often  developed. 
There  are  commonly  a  small  median  and  two  larger  lateral  eyes  ;  the  position 

Mem.  Soc.  Roy.  Sei.  Liege,  1847,  vol.  iv. — Description  des  Entomostraces  fossiles  des  terrains 
tertiaires  de  la  France  et  de  la  Belgique.  Mem.  Couronn.  Acad.  Roy.  Belg.,  1850,  vol.  xxiv. — 
Monographie  des  crustaces  fossiles  du  terrain  cretace  du  Duche  de  Limburg.  Mem.  Commiss.  Carte 
geol.  Nederlande.  Haarlem,  185i. —Reuss,  A.  E.,  Die  fossilen  Entomostracen  des  österreichischen 
Tertiärbeckens.  Haid.  naturw.  Abhandl.,  1850,  vol.  iii.,  pt.  1.— Die  Foramiiiiferen  und  Entomo- 
stracen des  Kreidemergels  von  Lemberg.  JMd.  iv.,  pt.  1,  lS61.~Jones,  T.  R.,  A  Monograph  of 
the  Entomostraca  of  the  Cretaceous  Formation  of  England.  Palaeont.  Soc,  1849.— Idem,  and 
Hinde,  G.  J.,  A  Supplemental  Monograph  of  the  Cretaceous  Entomostraca  of  England  and  Ireland. 
Ibid.,  1890.— Jones,  T.  R.,  A  Monograph  of  the  Tertiary  Entomostraca  of  England.  Ibid.,  1857. 
—Idem,  and  Sherborne,  C.  I).,  A  Supplemental  Monograph  of  the  Tertiary  Entomostraca  of 
England  Ibid.,  1889.— Jones,  T.  R.,  and  Kirkby,  J.  W.,  Notes  on  Palaeozoic  bivalved  Entomostraca, 
Nos.  1-32.  Ann.  Mag.  Nat.  Hist.,  1855-95.— Ä'^rprer,  ().,  Die  Ostracoden  der  Miocänschichten  bei 
Ortenburg  Neues  Jahrb.,  1858. -^Sjpeyer,  0.  W.  C,  Die  fossilen  Ostracoden  aus  den  Casseler 
Tertiarbddimgen.  Cassel  Jahresber.,  1863,  vol.  xiil-Brady,  G.  S.,  Crosskey,  H.  W.,  and 
Robertson,  D.,k  Monogi-aph  of  the  Post-Tertiary  Entomostraca  of  Scotland.  Palaeont.  Soc,  1874. 
-Jones,  T.  R  Kirkby,  J.  W^nd  Brady,  G.  S.,  A  Monograph  of  the  British  Fossil  bivalved 
Entomostraca  from  the  Carboniferous  Formations.  Ibid.,  1874,  \884..-Jones,  T.  A.,  and  Holl, 
H.  B  Notes  on  Palaeozoic  bivalved  Entomostraca.  Ann.  Mag.  Nat.  Hist.,  1869,  ser.  4,  vol.  iii.- 
^Zf^'  Ä^;  ;'•  *"^^^'!i«f'  ■^-  ^-^  A  Monograph  of  the  marine  and  fresh-water  Ostracoda  of  the 
Monn^tnW  i''  o  /  ,'''  T^"""'  i^^^"  ^"^^^"^  ^"^^  ^889-96,  vols.  iv.,  V . - Lienenklaus,  K, 
Monographie  der  Ostracoden  des  nord westdeutschen  Tertiärs.     Zeitschr.  Deutsch.  Geol.  Ges.,  1894, 

Trans  R;TSin\f'i«S«  ^T^^^'  ^^^  ,'^"  ^"  Carboniferous  Ostracoda  from  Ireland:  Sei. 
Geol  M^nn"  pLl  plf  '  1  "'  ""'l'  'o  To^^''^'  ^'  ^^  ^^e  Lower  Silurian  Ostracoda  of  Minnesota. 
Sat  Sd  1897  vo?  v'  ^1--  "'•^?*-  ^'  IP^—^herborn,  C.  D.,  The  literature  of  fossil  Ostracods. 
Zeitschr  Dent^;rV^;rr''''^^^^^^^  ^^.^'^  Tertiär-Ostrakoden  des  mittleren  Norddeutschlands. 
Ber  tnckenber^Nt  rp?'F  l^?'  'A^r^'^''''^  ^'^  Ostrakoden  des  Mainzer  Tertiärbeckens. 
R^ckfirCaDe  Brefon ■  r  'nfr^  ^'^'  .l^OÖ-J/a^^Äe..,  G.  F.,  Ostracoda  of  the  basal  Cambrian 
^f  Phvlloeari<fa  Proo  P^^^^  T'  ^>^^.^^^  "°^-  ^^^-Ohapman,  F.,  Son.e  Silurian  Ostracoda 
Ä  /  ^TneHean  Palen^^^^  fw"  ^^f"""'  ^^^4' "•  «'  ^^^'  ^^n.-Ulrich,  E.  0.,  and  Bassler, 
Ä.  *3.,  jNew  American  Paleozoic  Ostracoda,  pts.  ii.  and  iii  Proo  TT  q  NnV  M,i«  lonfiiQOS 
vol,.  XXX.,  xxxv.-Miocene  Ostracoda.     Maryland  Geol.  Surv,    Siocte  Vot  1904  -  '  ' 


SUBCLASS  II  EÜCRUSTACEA— OSTRACODA  737 

of  the  latter  being  often  indicated  on  the  exterior  of  the  valves  by  a  small 
"  eye  tubercle,"  or  ocular  spot. 

Save  for  one  or  two  families  (Cypridae)  Ostracods  are  almost  wholly 
restricted  to  marine  or  brackish  water.  They  are  gregarious,  and  occur  in 
vast  hordes  swimming  near  the  surface  or  creeping  over  the  bottom,  preferring 
usually  shallow  depths.  Their  remains  abound  in  nearly  all  the  principal 
formations,  and  they  are  often  important  rock-builders.  The  identification  of 
fossil  Ostracods  is  very  difficult  on  account  of  their  similarity  of  form  and 
ornamentation,  and  usually  minute  size ;  and  they  cannot  be  well  intercalated 
among  the  recent  series  for  reasons  already  given.  Sars  has  arranged  the 
living  forms  into  four  divisions,  Podocopa,  Platycopa,  Myodocopa  and  Cladocopa, 
but  assembling  the  families  into  higher  groups  is  not  attempted  here,  and 
only  the  more  representative  genera  can  be  noticed. 


Family  1.     Leperditiidae  Jones. 

Thick-shelled  Ostracoda,  mostly  of  considerahle  size.  Valves  smooth  and  glossy,  of 
very  compact  structure,  and  in  general  regularly  convex ;  hinge-line  straight ;  anterior 
and  posterior  ends  ohliquely  truncated  or  rounded,  and  neither  gaping  nor  excised. 

Leperditia   Rouault   (Fig.    1423).      Shell  sub-oblong  with  an  oblique  backward 
Swing,  from  2  mm.  to  22  mm.  long;  dorsal  edge  straight,  generally  angular  at  the 
extremities  ;    ventral  outline  rounded.     Valves  unequal,  the  right  larger  and  over- 
lapping  ventral  edge  of 
the  left.     Surface  often 
corneous  in  appearance, 
smooth,  and  eye  tubercle 
generally     present     on 
the        antero-dorsal 

quarter.        A     large  

rounded      sub  -  central  p     ,^23  ^^°'  ^^^^' 

1  •  •     .  ■         ■  Inochilina  gigantea  Roemer. 

muSCUiar    impnnt    pre-       Leperditia  Usingen  Schmidt.     Silurian ;  Silurian    erratic  ;    Lyck,   East 

sent  on  interior.     Ordo-  Wisby",  Gotland.     i/i-  Prussia.  •  2/3  (after  F.  Roemer). 

vician  to  Carboniferous. 

Leperditella  Ulrich.  Similar  to  above,  but  the  left  instead  of  right  valve  is  the 
larger,  and  has  a  groove  within  its  ventral  border  for  receiving  the  simple  edge  of 
the  right  valve.     Eye  tubercle  wanting.     Length  1  mm.  to  3  mm.     Ordovician. 

Isochilina  Jones  (Fig.  1424).  Like  Leperditia  except  that  the  valves  do  not  over- 
lap  but  are  equal  in  every  respect.     Ordovician  and  Silurian. 

Äparchites  Jones.  Shell  not  over  3  mm.  in  length,  equivalve,  sub-ovate  or 
oblong ;  ventral  edge  thickened,  often  bevelled.     Ordovician  and  Silurian. 

Schmidtella  Ulrich.  Ordovician.  Paraparchites  Ulrich  and  Bassler.  Carboni- 
ferous :  North  America. 


Hfefe^l^B  H^^^p 


Family  2.     Beyrichiidae  Jones. 

Small  equivalve  Ostracoda  with  a  long  straight  hinge.  Shells  vertically  sulcated  and 
more  or  less  lohate,  varying  from  forms  having  a  simple  median  depression  to  oihers  in 
ivhich  the  surface  of  the  valves  is  raised  into  numerous  low  lohes^  ridges  or  nodes. 

Primitiella  Ulr.  (Fig.  1425,  a).  Valves  with  a  broad,  undefined  mesial  depression 
in  the  dorsal  slope.     Ordovician  to  Devonian. 

VOL.  I  3  B 


^38  ARTHROPODA  phylüm  vii 

Primitia  Jones  and  Holl  (Fig.  1425,  h).  Has  well  -  marked  subcentral  pit  or 
sulcus  with  furrow  extending  to  the  hinge  line.     Ordovician  to  Permian. 

mcZella  Ulr.  (Fig.  1425,  d).  Like  Prirrntia  but  has  horn-hke  process  on  one 
or  both  sides  of  the  sulcus.     Ordovician.  ,       -,   ,  •     ^      x.        vi 

Ichmina  J.  and  H.  (Fig.  1425,  c).  Sulcus  is  replaced  by  a  smgle,  horn-like 
process.     Ordovician  to  Mississippian. 

Ulrichia  Jones.  Ordovician  to  Mississippian.  Synaphe,  BeyncUops%s,  Beynchiella 
Jones  and  Kirkby.     Carboniferous.  .    .  .     ,  .    -,  •  -a  a 

Eurychilina  Ulr.  (Fig.  1425,  g).  Like  Pn'mi^a  but  ventral  margm  provided 
with  a  Wide,  friU-like  border.     Ordovician  and  Silunan. 

/ones^i^«  Ulr.  (Fig.  1425,  f).  Valves  subovate  with  a  curved  ridge  on  the 
posterior  two-thirds.     Ordovician  and  Silurian. 


Fig.  1425. 

Paleozoic  Ostracoda.  a,  Primitiella  unicornis  Ulr.  x  i4/i.  b,  Friniitia  ci-ricinnatiensis  Miller,  x  i^/i.  c, 
.4ecfcmiTio  margitiata  Ulr.  x  i4/j.  d,  Dicranella  hicornis  Ulr.  x  lo/i.  e,  Ctenobolbina  ciliata  Emmons,  x  ^/i- 
f,  Jomsdla  crepidiformis  Ulr.  x  ^2/^.  g^  Eurychilina  reticulata  Ulr.  x  lO/j.  h,  Halliella  labrosa  Ulr.  x  ^4/^, 
i,  Kloedenia  centricornis  Ulr.  and  Bass.  x  i^/^.  j,  Tetradella  quadrilirata  H.  and  W.  x  i3/j.  fc,  Ceratopsis 
ckambersi  Miller,  x  i2/j.  i^  Kloedenella  turgüki  Ulr.  and  Bass. 
n,  Beyrichia  clavata  Kai.     x  i^/j.    o,  Drepanella  crasdnoda  Ulr. 


l4/i,    m,  Kirkhya  subquadrata  Ulr.     X  ^^/j. 
X  lO/j.    Pj  Dilohella  typa  Ulr.     x  l^/j. 


Bollia  Jones  and  Holl.  Valves  with  a  central  looped  or  horseshoe-shaped  ridge. 
Ordovician  to  Mississippian. 

Tetradella  Ulr.  (Fig.  1425,  j).  Valves  marked  by  four  more  or  less  curved 
vertical  ridges  united  ventrally.     Ordovician  and  Silurian. 

Geratopsis  Ulr.  (Fig.  1425,  Je).  Has  a  horn-like  process  arising  from  the  ex- 
tremity  of  the  posterior  ridge.     Ordovician  and  Silurian. 

Gtenoholbina  (Fig.  1425,  e),  Drepanella  (Fig.  1425,  o),  Halliella  Ulr.  (Fig.  1425, 
h).     Ordovician  to  Devonian. 

Beyrichia  M'Coy  (Fig.  1425,  n).  Valve  has  three  lobes  or  nodes  with  the  central 
one  the  smallest.     Ordovician  to  Devonian. 

Kloedenia  Jones  and  Holl  (Fig.  1425,  i) ;  Kloedenella  Ulr.  and  Bass.  (Fig. 
1425,  i).  Silurian  and  Devonian.  Dilohella  Vir.  (Fig.  14:25,  p).  Ordovician.  Hollina, 
Jonesina,  Treposella  Ulr.  and  Bass.     Devonian  to  Carboniferous. 

The  following  genera,  doubtfully  referred  here,  should  perhaps  be  regarded  as 
Paleozoic  Cytheridae  : 

Kirkhya  Jones  (Fig.  1425,  w).  Devonian  to  Permian.  Moorea  J.  and  K. 
Ordovician  to  Permian.  Strepula  J.  and  H.  Silurian  and  Devonian.  Macronotella 
Ulr.     Ordovician. 


SÜBCLASS  II 


EUCRUSTACEA— OSTRACODA 


739 


Family  3.     Cytheridae  Zenker. 

Minute  shells  of  generally  elongate-oval,  reniform  or  suh-quadrate  outline,  and  of 
dense  structure.     Surface  smooth,  punctate,  nodulose,  striate  or  spinöse;  hinge  generally 
denticulated,    the    right    valve    with 
two  teeth  in  most  cases,  and  the  left 
with  corresponding  pits. 


Fossil  species  of  this  family  are 
very  numerous  in  the  marine  deposits 
of  the  Cretaceous  and  Tertiary.  The 
resemblance  between  Cythere  and  the 
Devonian  genus  Strepula  is  so  decided 
as  to  indicate  relationship. 

Cythere  Müller  (Fig.  1426,  a). 
Shell  reniform  or  subquadrate, 
usually  widest  in  front ;  surface 
variously  ornamented  ;  hinge  teeth 
strong,  placed  one  at  each  end  of 
a  horizontal  bar  which  fits  into  a  corresponding  furrow  and  sockets  of  the  left  valve. 
Permian  to  Recent. 

Gythereis  Jones  (Fig.    1427).     Like  Cyther 
wanting.     Cretaceous  to  Recent. 

Gytheridea  Bosq.  (Fig.  1426,  c).     Differs  from  Cythere  in  having  hinge  beset  with 


Fig.  1426. 

Valves  of  fossil  Ostracoda.     a,  Cythere  hassleri  Ulr.     x  l^/j. 

h,  Cytheropterorv  nochsum  Ulr.  and  Bass.     x  17/].     c,  Cytheridea 

2)erarcuata  Ulr.      x  ^%.     d,  Pachydomella  tumida  Ulr.     x  l4/j. 

e,  Xestoleberismuelleriana(ha.m.).     X  30/j.    f,  Octonaria  Stigmata 

X  18/i. 


but  connecting  bar  of  the  hinge  is 


Ulr. 


Fio.  1427. 
Gythereis  quadrilatera  Roeraer.     Gault ;  Folkestone,  England,     x  25/j  (after  T.  Rupert  Jones). 

row  of  small  teeth  in  right  valve,  often  interrupted  in  the  middle,  and  with  corre- 
sponding pits  in  the  left  valve.     Jurassic  to  Recent. 

Cytherideis  Jones.  Shell  more  or  less  triangulär ;  hinge  simple.  Cretaceous  to 
Recent. 

Carbonia  Jones.  Carboniferous.  Cytheropteron  (Fig.  1426,  h),  Xestoleberis  (Fig. 
1426,  e)  and  Pseudocythere  Sars.     Tertiary  to  Recent. 


Family  4.     Thlipsuridae    Jones. 

Reniform  or  ovate  inequivalve  shells^  less  than  2  mm.  in  length,  the  margin  of  one 
valve  overlapping  that  of  the  other  more  or  less  completely ;  dorsal  margin  arcuate, 
ventral  sometimes  straight  or  slightly  sinuate.     Surface  with  two  or  more  deßnite  pits. 

Thlipsura  Jones  and  Holl.  Valve  generally  with  three  pits,  one  posterior  and  two 
in  the  anterior  half.     No  ornament.     Silurian  and  Devonian. 

Octonaria  Jones  (Fig.  1426,  /).  Differs  from  the  last  in  having  the  surface  of 
valves  raised  into  a  thin  spiral  or  annular  ridge  which  in  the  more  typical  forms  is 
8-shaped.     Silurian  and  Devonian. 

Phreatura  J.  and  K.  Posterior  end  of  shell  strongly  compressed  and  marked  by 
a  shallow  semicircular  pit ;  a  similar  but  smaller  pit  is  present  at  the  anterior 
extremity.     Carboniferous. 


740 


ARTHROPODA 


PHYLÜM  VII 


Family  5.     Oypridae  Zenker. 

Minute,  mostly  reniform  or  elongate-ovate,  corneous  or  corneo-calcareous  shells,  with 
thin,  somewhat  unequal  valves,  one  overlapping  the  other  either  ventrally  or  dorsally  or 
both. 

Recent  Cypridae  are  chiefly  fresh-water  inhabitants,  biit  this  is  true  in  a  lesser 
degree  of  the  fossil  forras.  All  the  Paleozoic  representatives  are  marine,  excepting 
perhaps  certain  Carboniferoiis  species.  Fossil  remains  are  extraordinarily  profuse  in 
certain  deposits,  and  the  family  is  an  important  rock-builder. 

Palaeocypris  Brongt.  Shell  0*5  mm.  long,  sub-ovate,  smaller  posteriorly  than  in 
front ;  surface  granulöse  and  finely  hirsute  in  dorsal  region.     Carboniferous. 

Cypris  Müller  (Fig.   1428).     Shell  reniform  or  oval,  thin,  translucent,  smooth  or 
A  hirsute,  often    punctate ;    hinge  edentulous,  somewhat 

thickened  ;  ventral  margin  often  sinuate.     Tertiary  to 
Q  Recent. 


Fio.  1428. 

Cypris  faha  Desm.      Miocene; 
Oeningen,  Switzerland.  A,  Dorsal,  and 

B,  Lateral  view.     i5/j  (after  Bosquet). 

C,  Valves  composing  fresh-water  lime- 
stone at  Nördlingen. 


Fig.  1429. 

Cypridea  rvaldensis 
Sowb.  Wealden  ;  Ober- 
kirchen, Hanover.     i5/j. 


Fig.  1430. 

Bo.irdia  curla  M'Coy. 
Low  er  Carboniferous  ; 
Ireland.  15/,  (after 
Kirkby). 


Cypridea  Bosq.  (Fig.  1429).  Like  Cypris,  but  with  a  small  hook-like  projection 
at  the  antero-ventral  angle.     Purbeck  and  Wealden. 

Bairdia  M'Coy  (Fig.  1430).  Shell  sub- triangulär  or  rhomboidal,  with  the 
greatest  height  near  the  middle,  generally  smooth,  both  extremities  narrowly  rounded 
or  pointed.  Dorsal  margin  more  or  less  strongly  convex  ;  hinge  formed  by  over- 
lapping edge  of  left  valve.     Ordovician  to  Recent ;  maxiraum  in  Carboniferous. 

Bythocypris  Brady.  Shell  smooth,  reniform,  ovate  or  elliptical  ;  left  valve  over- 
lappmg  the  smaller  right  valve  usually  on  both  dorsal  and  ventral  margins. 
lypically  Recent,  but  a  number  of  Paleozoic  forms  have  also  been  assigned  to  this 
genus.  ° 

Macrocypris  Brady.  Similar  to  the  last,  but  generally  more  elongate,  posteriorly 
more  acuminate,  and  the  right  valve  larger  than  the  left.  Ordovician  and  Silurian  ; 
also  Jurassic  to  Recent. 

Pontocypris  Sars.  Like  Bythocypris,  except  that  the  shell  is  very  delicate,  and 
the  hinge  is  simple  without  overlap.     Silurian,  Carboniferous,  Pleistocene  and  Recent. 

Family  6.     Cytherellidae  Sars. 


Fio.  1481. 

Cytherdln  mmpressa 
(Münst.).  Oligocene  ; 
Rflppelnionde,  Belginm. 
22/,  (after  Bosquet): 


_      Fmiily  characters  chiefly  displayed  by  soft  parts.      Shell  minute, 
mequivalve,  thick,  calcareous,  not  notched  anteriorly. 

Cytherella  Jones  (Fig.  1431).  Shell  oblong  or  sub-ovate, 
compressed  m  front ;  surface  generally  smooth,  but  sometimes 
undulatmg  and  marked  with  pits  and  granules.  Contact  margin 
Ol  the  larger  right  valve  grooved  for  reception  of  fiange-like 
edge  ofsma  1er  left  valve.     Ordovician  to  Recent. 

mr^If7  T^J^'T   ^""^    ^"^^-       ^il^ri^^-      (?)  Pachydomella 
Ulrich  (Flg.  1426,  d)  ■  Bosquetia  Brady.      Recent. 


SUBCLASS  II 


EUCRUSTACEA— OSTRACODA 


741 


Family  7.     Bntomidae  Jones. 

Shells  relatively  short,  strongly  convex,  reniformj  ovate  or  rounded  quadrate,  suh- 
equivalve,  with  a  more  or  less  well-marked  depression  near  the  middle  of  dorsal  region. 
Surface  sculpture  concentric  or  radiale. 

Entomis  Jones  (Figs.  1432,  1433).  Shell  sub-ovate  or  fabiform  ;  valves  with  a 
slightly  curved  sub -median  vertical 
furrow  extending  to  the  hinge  line  ; 
in  front  of  furrow  occasionally  a 
rounded  tubercle.  Surface  marked 
generally  with  raised,  concentric, 
transverse  or  longitudinal  lines. 
Ordovician  to  Carbon  iferous ;  very 
profuse  in  Devonian. 

Entomidella  Jones.  Like  En- 
tomis, but  with  furrow  extending 
entirely  across  the  valves  to  ventral 
edge.      Ordovician  and  Silurian. 

Elpe  Barr.      Shell    reniform,   3 
mm.  to  7  mm.  long,  with  depres- 
sion just  behind  the  middle  of  the 
dorsal  slope  ;  posterior  half  sometimes  strongly  inflated 
Ordovician  and  Silurian. 


Fio.  1432. 

Entomis  pelagica  Barr. 
Lower  Devonian  (F) ; 
Konieprus,  Bohemia. 


Fig.  1433. 

Entomis  serrato-striata  (Sandb.). 
Upper  Devonian  ;  Weilburg, 
Nassau.  Ä,  Fragment  of  matrix, 
i/i.  B,  Ventral  and  lateral  aspects. 
5/i.     C,  Impression  of  valve,  9/i. 

Delicate  radial  ornament. 


Family  8.     Oypridinidae  Sars. 

Shells  equivalve  sub-elliptical  to  oblong^  convex,  smooth  or  punctate,  and  sometimes 
ribhed,  especially  in  posterior  half.     Anterior  end  with  a  notch  and  hook-like  hood  over- 
an  opening  left   between  edges  of  valves  for  protrusion  of  the  lower  antennae  ; 
ior  extremity  frequently  acuminate. 

Milne  Edw.  (Fig.   1434).      Shell  generally  acuminate,  oviform,  rarely 


Fig.  1434. 

Cypridina  primaeva^de 
Kon.).  Goal  Measures ;  Braid- 
wood,  England.  «/^  (after 
Jones,  Kirkby  and  Brady). 


Fig.  1435. 

Cypridella  wrightii  J.  K.  and  B.  Lower 
Carboniferous  ;{  Cork,  Ireland.  **/i  (after 
Jones,  Kirkby  and  Brady). 


Fig.  1436. 

Cyprella  chrysalidea((le 
Kon.).  Lower  Carboni- 
ferous ;  Cork,  Ireland. 
4/i  (after  Jones,  Kirkby 
and  Brady). 


oblong ;  antero-dorsal  edge  projecting  beak-like  over  the  strongly  defined  notch  ; 
muscle  spot  large,  sub-central,  often  visible  on  exterior.     Ordovician  to  Recent. 

Gypridinella  J.  K.  and  B.  Like  Cypridina,  but  having  the  antero- ventral  region 
projecting  somewhat  prow-like  and  generally  beyond  the  hook.     Carboniferous. 

Gypridellina  J.  K.  and  B.  Differs  from  the  last  in  having  a  tubercle  or  lump 
above  the  centre  of  the  valve.     Carboniferous. 

Cypridella  de  Kon.  (Fig.  1435).  Like  Cypridellina,  except  that  it  has  a  curved 
sulcus  behind  the  tubercle.     Carboniferous. 

Cyprella  de  Koninck  (Fig.  1436).  Shell  much  as  in  the  last,  but  annulate. 
Carboniferous. 

Sulcuna,  Rhombina  J.  K.  and  B.  ;  Cypresis,  Cyprosina  Jones.     Paleozoic. 


^42  ARTHROPODA  phylum  vii 

Fainily  9..    Entomoconchidae. 
Shell  suh-cjlobose,  more  or  less  inequivalve  ;  anterior  edge  truncate  and  with  central 
Portion  of  nmrgin  inturned  so  as  to  leave  a  simple  or  sinuate  sht.     Beah  not  developed. 
Entomoconchus  M'Coy  ;  Offa  Jones,  Kirkby  and  Brady.     Carboniferous. 

Geological  Range  of  the  Ostracoda. 

Numerous  supposed  Ostracoda  {Bradoria,  Beyrichona,  etc.)  liave  been  described 
from  the  Cambrian,  biit  all  of  these  now  prove  to  be  Brancliiopods.  The  earliest 
undoubted  Ostracoda  are  indicated  by  a  few  species  of  Leperditia  found  m  the 
Beekmantown  beds  (Lower  Ordovician)  of  Tennessee.  Diiring  the  Middle  and 
Upper  Ordovician  these  Crustaceans  flourished  greatly,  and  form  excellent  horizon 
markers.  The  prevailing  Ordovician  and  Sihirian  types  belong  to  the  Leperditiidae 
and  Beyrichiidae,  although  toward  the  close  of  the  Silurian  numerous  Cypridae  make 
their  appearance. 

Devonian  Ostracoda  are  less  numerous,  but  manifest  essentially  the  same  types  as 
in  the  earlier  periods.  Here,  however,  the  larger  Leperditiidae  are  entirely  wanting. 
Although  many  small  species  of  archaic  genera  persist  in  the  Carboniferous,  the  aspect 
of  the  fauna  is  changed  by  the  strong  development  of  Cypridinidae.  Thereafter 
Ostracods  are  but  sparsely  represented  until  the  Cretaceous,  when  certain  genera, 
especially  Gythere,  develop  a  surprising  variety  of  species,  Little  difference  can  be 
detected  between  Tertiary  Ostracods  and  their  modern  descendants,  although  on 
account  of  the  facilities  for  studying  the  anatomy  of  the  soft  parts  it  has  been  possible 
to  distingiiish  many  more  genera  among  the  living  forms. 

[The  above  revision  of  the  groups  Branchiopoda  and  Ostracoda  has  been  prepared  by 
Dr.  R.  S.  Bassler.— Editor.] 

Superorder  4.    OIRRIPEDIA  Bur  meist  er.    Barnacles.^ 

Sessile,  mostly  hermaphroditic  animals,  endosed  in  a  memhranous  mantle  which 
is  often  covered  with  calcareous  plates.    Body  attached  by  the  anterior  extremity  of  the 

^  Literature  :  A.     Recent  Forms : — Thompson,  J.  V.,  Zoological  Researches  and  Illustrations. 

1.  Cork,  1830. — Discovery  of  the  Metamorphosis  in  the  Lepades,  etc.     Phil.  Trans.  Roy.  Soc,  pt. 

2,  1835. — Burmeister,  H.,  Beiträge  zur  Naturgeschichte  der  Rankenfüssler.  Berlin,  1834. — Martin- 
Saint-Ange,  G.  J.,  Memoire  sur  l'organisation  des  Cirripedes.  Mem.  Savans  Strang.,  Acad.  Sei., 
Paris,  1835,  vol.  y\.— Darwin,  C,  A  Monograph  of  the  Sub-Class  Clrripedia.  Ray  Soc,  1851-54, 
vols.  i.,  \i.—Hoek,  P.  P.  C,  Report  on  the  Cirripedia.  Rept.  Challenger  Exped.,  ZooL,  viii.,  x., 
lS8Z-8i.—AtiHvülius,  0.  W.  S.,  Studien  über  Cirripeden.  Svensk'.  Vetensk.  Akad.  Handl.,  1893, 
vol  xxvi.,  no.  I.—Oroom,  T.  T.,  On  the  Early  Development  of  the  Cirripedia.  Phil.  Trans.  Roy. 
Soc,  1894,  vol.  c]xxxv.— Hansen,  H.  /.,  Phyllopoda  and  Cirripedia.  Plankton  Expedition,  1895. 
—Oruvel,  A.,  Monographie  des  Cirrhipedes.     Paris,  1905. 

B.  Fossil  Forms.— Sowerby,  J.,  and  /.  de  C,  The  Mineral  Couchology  of  Great  Britain. 
London,  1812-30.  — Roemer,  F.  A.  Die  Versteinerungen  des  norddeutschen  Kreidegehirges.  Hanover, 
1840-41.— Z>amm,  C,  A  Monograph  of  the  Fossil  Lepadidae  of  Great  Britain.  Palaeont.  Soc, 
1851.— A  Monograph  of  the  Fossil  Balanidae  and  Verrucidae  of  Great  Britain.  Ibid.,  1855.— 
Bosquet,  J.,  Monographie  des  Crustaces  fossiles  du  terrain  cretace  du  Duche  de  Limbourg.  Mem. 
Commiss.  Carte  geol.  Nederlande,  1854.— Notice  sur  quelques  Cirripedes  recemment  decouverts 
dans  les  terraius  cretaces  du  Duche  de  Limbourg.  Haarlem,  1857.— Reuss,  A.  E.,  Ueber  fossile 
Lepadiden.  Sitzungsber.  Akad.  Wiss.  Wien,  1864,  vol.  x\\x.—Wood%oard,  IL,  On  Turrilepas,  etc. 
Quar.  Journ.  Geol.  Soc,  1865,  vol.  xxi.— Barrande,  J.,  Systeme  Silurien  du  centre  de  la  Boheme, 
I.  Siippl.,  lS72.—Seguenza,  G.,  Ricerche  palaeontologiche  intorno  di  Cirripedi  terziarii  della  Provincia 
dl  Messma,  Pts.  i.,  ii.,  Naples,  1873-76.  Marsson,  J.,  Die  Cirripeden  und  Ostracoden  der  weissen 
Schreibkreide  der  Insel  iRügen.  Mittheil,  naturw.  Ver.  Neu- Vorpommern  und  Rügen,  1880,  vol. 
xn.~Zütel,  K.  A.,  Bemerkungen  über  einige  fossilen  Lepaditen  aus  dem  lithographischen  Schiefer 
und  der  oberen  Kriede.  Sitzungsber.  Bayer.  Akad.  Wiss.,  1884,  vol.  xiv.— Faber,  ö.  L.,  Remarks 


süBCLASs  II  EUCRÜSTACEA— CIRRIPEDIA  743 

head ;  obscurely,  and  at  times  not  at  all  segmented  ;  posterior'  portion  with  at  most 
six  pairs  of  himmous  legs  or  cirri,  which^  howevei\  may  he  fewer  in  numher  or 
altogether  absent. 

The  typictal  and  best  known  Ciiripedes  {Balanidae,  Lepadidae)  differ  so 
widely  from  all  other  Crustacea  in  their  external  form,  solid  calcareous  shells, 
slightly  developed  respiratory  and  sensory  organs,  and  especially  in  their 
hermaphroditic  sexual  apparatus,  that  until  1830  they  were  commonly  classed 
with  the  Mollusca.  About  this  time  J.  V.  Thompson  and  Burmeister  showed 
that  these  Cirripedes  pass  through  a  nauplius  stage,  and  that  directly  before 
attachment  both  Baianus  and  Lepas  undergo  a  C?/p7S-stage,  thus  showing  very 
clearly  their  relation  to  the  Eucrustacea. 

All  Cirripedes  are  marine  animals.  Those  with  calcareous  shells  attach 
themselves  to  stones,  wood,  mollusks,  crabs,  corals  and  sea  plants,  and  often 
Cover  rocky  coasts  in  myriad  numbers.  Some  genera  {Coronula,  Chelonohia) 
attach  themselves  to  whales  and  turtles ;  some  {Pyrgoma,  Palaeocreusia) 
become  embedded  in  corals,  and  others  bore  into  shells  of  mollusks  or 
lead  a  parasitic  existence  on  Decapods  or  within  the  shells  of  other  Cirripedes. 
Most  Barnacles  inhabit  shallow  water,  but  certain  genera  occur  at  great 
depths,  from  1900  to  2000  fathoms  (Scalpellum,  Verruca).  Many  of  the 
living  families  are  naked,  and  naturally  only  those  possessing  shells 
(Thoracica)  have  left  fossil  remains,  although  some  of  the  tubulär  cavities  in 
molluscan  shells  may  have  been  perforated  by  naked  Cirripedes.  Fossil 
forms  occur  sparingly  in  the  older  strata,  and  do  not  become  abundant  until 
near  the  close  of  the  Tertiary. 

Order  1.     THORACICA  Darwin. 

Body  indistinctly  segmented,  and  enclosed  in  a  membranous  mantle  in  which  calcare- 
ous plates  are  usually  developed.  Six  pairs  of  cirri  present.  Mostly  hermaphroditic, 
sometimes  with  complemental  males. 

The  relations  of  the  first  two  of  the  foUowing  families  to  the  other  members  of 
the  Order  are  conjectural. 

Family  1.     Lepidocoleidae  Clarke. 

Body  covered  with  two  vertical  coliimns  of  overlapping  plates,  those  of  one  series 
alternating  with  those  of  the  other.  Terminal  or  caudal  plate  axial.  Basal  or  cephalic 
portion  of  the  body  with  a  ventral  curvature.  Apices  of  the  plates  on  the  dorsal  margin. 
No  accessory  plates. 

Lepidocoleus  Faber  (Fig.  1437).  Elongate,  blade-shaped  ;  dorsal  edge  the  thicker, 
ventral  edge  sharper  and  linear.     The  two  series  of  plates  niake  a  complete  enclosure, 

on  some  Fossils  of  the  Cincinnati  Group.  Journ.  Cincin.  Soc.  Nat.  Sei.,  1887,  vol.  ii. — Hall,  J., 
and  Clarke,  J.  M.,  Palaeontology  of  New  York,  1888,  vol.  y\\.— Clarke.,  J.  M.,  Notes  on  certain 
.Fossil  Barnacles.  Amer.  Geol.,  1896,  vol.  xwiu— Matthew,  G.  F.,  On  occurrence  of  Cirripedes  in  the 
Cambrian.  Trans.  N.  Y.  Acad.  Sei.,  1896,  vol.  xw.—Logan,  W.  N.,  Cirripeds  from  Cretaceous  of 
Kansas.  Kansas  Univ.  Quar.  1897,  vol.  \\.  — Woodward,  H.,  Cirripedes  from  the  Trimmingham 
Chalk  in  Norfolk.  Geol.  Mag.  1906,  dee.  5,  vol.  \n.~Idem,  on  the  genus  Laricula.  Ibid.,  1908, 
vol.  v.—De  Alessandri,  G.,  Studi  monografici  sui  Cirripedi  fossili  d'  Italia.      Palaeontogr.  Ital., 

1906,  vol.   xii. Idem,  Osservazioni  sopra  aleuni  Cirripedi  fossili  della  Francia.     Atti  Soc.  Ital. 

Nat.,'  Milano,  1907,  vol.  \\x.-~Reed,  F.  R.  C,  Structiire  of  Turrilepas  and  its  allies.  Roy.  Soc. 
Edinb.,  1909,  vol.  xM.  —  Withers,  T.  H.,  The  Cirripede  genus  Scalpelhim.  Geol.  Mag.  1910, 
dee.  5    vol.  vii.—Idem,  The  Cirripede  Brachylepas  cretacea  H.  Woodward.     Ibid.,  1912,  vol.  ix. 


744 


ARTHROPODA 


PHTLUM  VII 


iilerlocked  on  the  dorsal  edge,  biit  are  only  in  apposition  on  tlie  ventral 
edge,  wliere  tliey  were  undoubtedly  capable  of  dehiscence  for 
the  Protrusion  of  the  appendages.  This  is  tlie  most  primitive 
geniis  of  the  group.     Ordovician  to  Devonian. 

Family  2.     Turrilepadidae  Clarke. 

Body  with  four  to  six  vertical  columns  of  triangulär  plates, 
two  of  the  columns  heing  small,  accessory  and  sometim.es  much 
modified  in  shape.      Gaudal  plate  patelliform,  axial. 

Fid.  1437.  Turrilepas     Woodw,     {Plumulites 

Lepidocoieus  mriei  Clarke.    Barr.)  (Fig.    1438).      Body  elongate- 

ventral  views.  large    triangulär    overlapping    scales, 

some  of  which  are  keeled  in  the 
middle.  Besides  having  concentric  Striae,  the  surface  may  be 
radially  lined  or  punctated.  Cambrian  (?)  to  Upper  Devonian. 
Strohilepis  Clarke.  Composed  of  four  columns  of  over- 
lapping plates,  two  of  which  are  of  large  and  equal  size. 
Of  the  other  two  intervening  columns,  one  consists  of  a 
few  very  small  plates,  and  the  other  is  modified  into  a  series 
of  grooved  spines  which  appear  to  overlap  one  another  at 
their  bases,  and  to  lie  opposite  the  column  of  small  plates. 


Fig.  1438. 


Caudal    extremity   terminated    by  a   circular 
plate,  against  the  sides  of 
column.     Middle  Devonian 


Turrilepas  ivrightianus   de 

.     ,  .   ^     Koninck.     Silurian ;  Dudley, 

COnical,    axial    England.     A,  Complete  indi- 


plate,  against_  the  rides  of  which  lies  the  first  plate  in  each   Ä  entrged^a'fter' Wo" 


ward). 


Family  3.     Lepadidae  Darwin.     (Goose  Barnacles). 

Shell  pedunculated,  composed  mainly  of  the  paired  terga  and  scuta,  the  unpaired 
canna,  and  a  variable  numher  of  small  calcareous  plates,  some  of  which  Cover  the 
flexible  peduncle;  others  take  part  in  the  capitulum.      The  calcareous  plates  are  never 

Archaeolepas  Zittel  (Fig.    1439).      Peduncle  flattened,  the  two  principal  surfaces 


Fio.  143'.». 
Archaeoiejjax  rei/lru- 
hu;heri  (Opp.).  Litliu- 
graphic  Stone  ;  Kel- 
heiin,  Bavaria.  Vi-  C', 
Carina  ;  R,  Rostrum  ; 
'S,  Scutum  ;  T,  Terguni. 


Fig.  1440. 
A,  Loricula  laevissima  Zitt 
Senonian  ;     Dülmen,    West- 
phaha.    Vi.     B,  C,  Lorimla 
•'j.VnocaDames.  Cenomanian 
Lifibanon. 


Fig.  1441. 

Scalpellum  gallicum 
Hebert.  Upper  Cretaee- 
ous  ;  Meudon,  near  Paris. 
'^/i  (after  Hebert). 


Vi  aiKi  2/j. 
andaLnut:^.:3Xe"ClX::^^ä:ior^  unpai./ea.„a, 


I 


SUBCLASS  II 


EUCRUSTACEA— CIRRIPEDIA 


745 


Pollicipes  Leacli  (Polylepas  Blainv.).       Capitulimi  coinposed  of  numerous  (eighteen 
to  one  hundred)  plates,  anioiig  wliicli  the  scuta,  terga,  rostrum  and  carina  are  dis- 

A 


Capitulum  of  Scalpellum  fossulum  Darwin. 
Upper  Cretaceous ;  Norwich,  England.  2/j. 
C,  Carina ;  L,  Laterale  superius  (upper  latus) ; 
R,  Rostrum  ;  S,  Scutum  ;  T,  Tergum  ;  cl, 
Carino  -.latus  ;  il,  Infra  •  median  latus  ;  rl, 
Rostral  latus  ;  sc,  Sub-carina  ;  sr,  Sub-rostrum 
(after  Darwin). 


Fig.  1443. 

Scalpellum  fossulum  Darwin. 
Upper  Cretaceous ;  England. 
Carina  much  enlarged  (after 
Darwin). 


Fkj.  1444. 

Lepas  anatifera  Linn. 
Recent ;  Mediterranean.  C, 
Carina  ;  P,  Peduncle  ;  S, 
Scutum ;  T,  Tergum. 


tinguishable  by  their  size.  Lateralia  generally  in  two  columns.  Peduncle  mem- 
branous  with  minute  scales.  Upper  Jura  to  Recent.  Doubtfully  recorded  from 
the  Silurian. 

Squama,  Stramentum  Logan.      Upper  Cretaceous  (Niobrara) ;  Kansas. 

Scalpellum  Leacli  (Figs.  1441-1443).  Capitulum  with  twelve  to  fifteen  pieces. 
Terga  and  scuta  much  larger  than  in  Pollicipes  and  of 
very  characteristic  form.  Carina  narrow,  long,  with 
arched  surface.  Peduncle  covered  with  fine  scales, 
rarely  naked.  Cretaceous  to  Recent,  and  doubtfully 
recorded  from  the  Silurian. 

Le2}as  Linn.  (Fig.  1444).  Peduncle  naked. 
Capitulum  consisting  of  only  two  very  large  tri- 
angulär scuta,  two  small  terga,  and  a  single  carina. 
Pliocene  and  Recent. 

Poecilasma    Darwin.       Capitulum     consisting     of 
three,  five  or  seven  pieces.      Carina  extending  only  to 
base    of    the    terga,    the 
Scuta  sub-oval.     Tertiary  and  Recent. 


Fig.  1445. 
BrachyUpas   naissanti   (Hubert)  (  = 


latter    sometimes    wanting.    P^M^^s^lo,vissim^Lsqx^en^t.)._  Upper 


Rostrum  ;  s,  Scutum ; 
l,  upper  latus ;  t,  tergum ;  c,  carina ;  i.s., 
imbricating  plates.    Vi  (after  Withers). 


Family  4.     Brachylepadidae  H.  Woodward. 

Shell  sessile,  with  a  large  numher  of  plates,  the  arrangement  of  which  indicates  a 
transition  from  the  Lepadidae  towards  the  Balanidae. 

The  Single  known  genus  Brachylepas  H.  Wood  ward  (Fig.  1445)  occurs  in  the 
Upper  Senonian  of  England  and  the  continent  of  Europe. 


746 


AETHROPODA 


PHYLUM  VII 


Family  5.     Verrucidae  Darwin. 
Shells  sessile  and  composed  of  six  pieces.      Of  the  scuta  and  terga  only  those  of  one 


side  are  free  the  others  heing  fused  with  the  rostrum  or  canna. 

The  solitary  genus  Verruca  Sclium.,  ranges  from  tlie  Cretaceoiis  to  Recent. 


Family  6.     Balanidae  Darwin.     (Acorn  Barnacles). 

Shell  ohtusely  conical,  cireular  or  oval  in  cross  section,  with  hroad,  offen  calcareous 
and  cellular  hase ;  composed  of  four  to  ten  ''  compartments"  more  or  less  completely  fused 

at  their  sides,  and  two  pairs  of  free  terga  and  scuta 
which  dose  the  upper  aperture  like  an  operculum. 

Of  tlie  lateral  plates  whicli  compose  the  crown- 
shaped  immovable  test,  two  are  designated  as  carina 
AB  c 


Fig.  1446. 

Diagram  of  the  sliell  of  Baianus.  B, 
Basis  ;  C,  Carina  ;  CL,  Carino  -  lateral 
compartment ;  L,  Lateral  compartinent ; 
R,  Rostrum  ;  RL,  Rostro-lateral  com- 
partment. Each  valve  or  "compart- 
ment" consists  of  a  central  "paries"  (p) 
flanked  by  "alae"  (a)  or  "radii  "  (r). 


Fig.  1447. 

Scutum  and  tergum  of  Baianus.  A,  External  aspect  of  tergum, 
sliowing  "spur"  below  and  "beak"  above.  B,  Internal  view  of 
scutum,  showing  muscular  scar  (x).  C,  Internal  view  of  tergum 
(after  Darwin). 


and  rostrum,  the  pieces  lying  between  and  occurring  in  pairs  being  called  lateralia.     If 
^  ;.  additional     plates    are     inserted 

among  the  lateralia,  they  are 
termed  according  to  their  position 
rostro-  or  carino  -  lateralia.  The 
scuta  and  terga  lie  free  oii  the 
back  of  the  aniinal,  and  in  fossil 
forms  are  generally  lost.  They 
have  a  very  characteristic  form, 
and  hence  are  of  great  systematic 
importance.  Since  among  fossil 
species,  however,  only  the  mar- 
ginal plates  are  for  the  most  part 
preserved,  the  determination  of 
their  structural  characters  is  often 
quite  uncertain. 

Baianus    Lister   (Figs.    1446- 
,.  j  .    ,  i    p   .  1449),       Shell    low,    conical    or 

cyhndncal,  composed  of  six  pieces.     Opercular  plates  sub-triangiüar  ;  base  membranous 

or  calcareous.     Eocene  to  Recent. 

Protohalanus  Whitf.     Affinities  doubtful.     Composed  of  twelve  plates,  of  which 

bas^"^  MWdL  dIvoS      ''''*'''"'  ''^^^^'  ^""^''^^'^  '"^  ^^^  ^^^^  ^'''^^  ^^^^  ^'^'  *^' 

Pn^.f-''''^^^'''"^'     ^V^l,^^^^P°«^d  of  «ix  solid  pieces.     Base  calcareous,  cup-shaped  ; 
epizoic  on  Sponges  and  Alcyonarians.     Pliocene  and  Recent. 


Fig.  1448. 
Balanw  concamis  Bronn.    Crag;  Sutton,  England.     .4,  Shell. 
Vi  (after  Darwin). 


B,  Tergum.     C,  Scutum. 


suBCLASs  II  EUCRUSTACEA— CIRRIPEDIA  747 

Pyrgoma  Leacli  (Creusia  Blainv.).  Shell  formed  of  a  single  piece.  Base  cup- 
sliaped  or  sub-cylindrical ;  epizoic  on  Corals.  Lower  Devoniaii  (?).  Tertiary  and 
Recent. 

Palaeocreusia  Clarke  (Fig.  1450).  Affinities  doubtful.  Sliell  in  one  piece,  with 
a  deep  cylindrical  base ;  epizoic  on  corals.     Lower  Devonian. 

Coronula  Lam.     Composed  of  six  lateralia,  with  thin,  deeply  folded  walls  dividing 


Fio.  1450. 

Palaeocreusia      devonica      Clarke. 
j^   j^j,j  Embedded  in  Favosites.     Middle  De- 

vonian   (Onondaga    limestone)  ;    Le 
Baianus  jyictus  Münst.     Miocene  ;  Dischingen,  Würtemberg.  Koy,  New  York. 

the  interior  space  into  Chambers  which  open  at  the  lower  side  of  the  shell.  Base 
niembranous  ;  epizoic  on  whales.      Pliocene  to  Recent, 

Ghthamahis  Ranz.  (Euraphia  Conrad).  Shell  depressed,  composed  of  six  pieces. 
Base  membranous.      Cretaceous,  Miocene  and  Recent. 

Pachylasma  Darwin.  Shell  in  the  young  with  eight  pieces,  which  afterwards  become 
six,  or  by  coalescence  of  the  lateralia  are  apparently  reduced  to  four.  Base  calcareous. 
Pliocene  to  Recent. 


Superorder  5.     MALACOSTRACA  Latreille. 

Eucrustacea  having,  in  Recent  forms,  typically  fourteen  {rarely  fifteen)  hody- 
somites  hesides  the  telson.  All  the  somites  {except  the  fifteenth)  bear  appendages 
which  are  differentiated  into  two  groups,  a  thoracic  of  eight  and  an  abdominal  of 
six  pairs. 

The  Classification  of  the  Malacostraca  has  undergone  considerable  modifi- 
cations  at  the  hands  of  zoologists  within  recent  years,  and  further  research  is 
necessary  before  some  of  the  fossil  forms  can  be  assigned  to  their  proper 
places  in  the  newer  arrangements. 

The  basis  of  the  new  Classification  is  the  recognition  of  the  fact  that  what 
has  been  called  the  "  caridoid  facies "  is  a  common  inheritance  from  the 
primitive  stock  of  the  Malacostraca  (possibly  excepting  the  Phyllocarida), 
and  does  not  imply  close  affinity  between  the  various  groups  presenting  it. 
The  Chief  characters  that  go  to  make  up  this  facies  are  the  stalked  eyes,  the 
scale-like  exopodite  of  the  antenna,  the  thoracic  carapace,  the  natatory 
exopodites  of  the  thoracic  limbs,  the  large  and  ventrally  flexed  abdomen, 
and  the  "  tail-fan  "  formed  by  the  uropods  and  telson.  The  group  "  Schizo- 
poda "  has  long  served  as  a  receptacle  for  primitive  forms  possessing  these 
characters,  and  its  dismemberment  into  the  three  orders,  Anaspidacea, 
Mysidacea  and  Euphausiacea,  is  attended  by  the  inconvenience  that  the 
characters  distinguishing  these  Orders  are  but  rarely  to  be  discovered  in 
fossils. 


n 


ARTHKOPODA  p^ylüm  vii 

748 

Following  is  the  scheme  of  Classification  here  adopted  :- 

Series  I.  Leptostraca. 

Division  A.  Phyllocarida. 
Order  Nebaliacea. 
Series  IL  Eumalacostraca. 

Division  A.  Syncarida. 
Order  Anaspidacea. 

Division  B.  Peracarida. 

Order  1.  Mysidacea. 

„  2.  Cumacea. 

„  3.  Tanaidacea. 

„  4.  Isopoda. 

,,  5.  Amphipoda 

Division  C.  Eucarida. 

Order  1.  Euphausiacea. 
„       2.  Decapoda. 

Division  D.  Hoplocarida. 
Order  Stomatopoda. 

Series  I.    LEPTOSTRACA  Claus. 
Division  A.    PHYLLOCARIDA  Packard/ 

Order  1.  NEBALIACEA  Calman. 

Abdomen  of  seven  somites  (in  the  Becent  forms),  the  last  of  which  is  without 
appendages,  and  a  telson  bearing  a  pair  of  movaUe  furcal  raini.     Carapace  present, 

1  Literature :  Salter,  J.  W. ,  On  some  new  Fossil  Crustacea,  etc.  Quar.  Journ.  Geol.  Soc,  1856-62, 
vols.  xii.,  xix. — On  New  Sihirian  Crustacea.  Ami.  Mag.  Nat.  Hist.,  1860,  vol.  v. — Hall,  J., 
Palaeontology  of  New  York,  1859,  vol.  iii.— 16tli  Ann.  Rept.  N.  Y.  State  Cabinet  Nat.  Hist.,  1863. 
—Woodward,  IL,  On  a  new  Genus  of  Phyllopodous  Crustacea.  Quar.  Journ.  Geol.  Soc,  1866, 
vol.  xxii.— Geol.  Mag.,  1872,  1882,  1SS5.— Claus,  G.,  Ueber  den  Bau  und  die  systematische 
Stellung  von  Nebalia.  Zeitschr.  wissensch.  Zool.,  1872,  vol.  xxii. — Über  den  Organismus  der 
Nebaliden.  Arb.  zool.  Inst.  Wien,  1888,  vol.  viil—Baro'ande,  J.,  Systeme  Silurien  du  centre  de 
la  Boheme,  I.  Suppl.,  1872. — Etheridge,  R.,  On  Ditliyrocaris  andAnthrapalaemon  in  Scotland.  Quart, 
Journ.  Geol.  Soc,  1879,  vol.  xxxw.  —  Whitßeld,  R.  P.,  Notice  of  new  Forms  of  Fossil  Crustacea, 
etc  Amer.  Journ.  Sei.,  1880,  vol.  x\x.—Glarke,  J.  M.,  New  Phyllopod  Crustacea  from  the 
Devonian.  Amer.  Journ.  Sei.,  1882,  vol.  xxiii. — New  Discoveiies  in  Devonian  Crustacea.  Ihid.,  1883, 
vol.  XXV. — Ueber  deutsche  oberdevonische  Crustaceen.  Neues  Jahrb.,  1884,  vol.  i. — On  the 
Structure  of  the  Carapace  in  Rhinocaris,  etc  Amer.  Nat.,  1893,  vol.  xxvii. — 14th  Rept.  State 
Geol.  N.  Y.  I.,  1898.— ^eec/ier,  ö.  E.,  Ceratiocarida,  from  the  Upper  Devonian  Measures.  2nd  Geol. 
Surv.  Penn.  Rept.  PPP,  \^%\.—Idevi,  Revision  of  the  Phyllocarida  from  the  Chemung  andWaverly 
Groups  of  Pennsylvania.  Quar.  Journ.  Geol.  Soc,  1902,  vol.  \\\\\.— Jones,  T.  R.,  and  Woodward, 
H.,  Various  Papers  in  Geol.  Mag.,  1884-94,  and  Reports  1-12  of  Comm.  on  Fossil  Phyllopoda,  Brit. 
Assoc.  Adv.  Sei.,  1883-95. — Novdk,   0.,  Remarques  sur  le  genre  Aristozoe.     Sitzungsber.  bohm. 


süBCLAss  II  EUCKUSTACEA— PHYLLOCARIDA  -    749 

with  a  movahly  articulated  rostral  plate.  Eyes  pedunculate  ;  thoracic  limbs  foliaceous  y 
no  brood-plafes  (oostegites) ;  first  four  pairs  of  abdominal  limbs  biramous,  last  two 
pairs  reduced. 

This  definition  is  based  on  the  characters  of  the  Recent-  genus  Nebalia 
(Fig.  1452)  and  its  allies,  which  Packard  first  grouped  together  under  the 
name  Phyllocarida  with  the  fossils  described  below.  Many  of  the  fossils^ 
however,  show  important  difFerences  from  the  Recent  genera  {e,g.  in  the 
number  of  abdominal  somites)  which  may  eventually  require  the  establishment 
of  new  Orders  if  they  are  to  be  retained  within  the  division  of  Phyllocarida. 

Cephalic  appendages  have  not  been  satisfactorily  determined  in  any  fossil 
species,  although  traces  of  them  have  been  noticed  in  a  few  genera  (Cryptozoe, 
Ceratiocaris,  Bhinocaris).  In  the  absence  of  contrary  evidence  there  is  reason 
to  suppose  that  the  appendages  of  the  head,  thorax  and  abdomen  were 
after  the  type  of  Nebalia,  since  there  is  close  correspondence  in  the  form  of 
carapace,  rostrum  and  abdomen.  Owing  to  the  non-preservation  of  limbs, 
distinctions  within  the  group  are  based  principally  on  differences  in  the 
structure  of  the  carapace,  and  in  number  of  body  -  segments.  Several 
fossil  genera  (Echiriocaris,  Bhinocaris,  Mesothyra)  bear 
a  distinct  optic  node  or  pit,  suggesting  a  sessile 
simple  eye  in  contradistinction  to  the  stalked  facetted 
eye  of  Nebalia.  In  these  genera,  also,  large  cuspidate 
masticatory  organs  (Fig.  1451)  have  been  found, 
which  were  apparently  attached  only  by  means  of 
muscles ;  these  are  compared  by  H.  Woodward  with 
the  gastric  teeth  of  the  lobster.  From  the  Middle 
Cambrian  of  British  Columbia  Walcott  has  described 
wonderfully  preserved  specimens  of  Phyllocarida 
(new  species    of  Hymenocaris,  etc.)  showing   append-  fig.  i45i. 

ages,     which    will    probably    repay    more    detailed      Gastric  teeth  of  EcUnocaHs 

.°'.,.  ^  "^  ^    "^  punctata    Hall.       Hamilton  ; 

investlgatlOn.  Pratt's  Falls,  New  York,    i/i- 


Suborder  A.     NEBALIINA  Clarke. 

Carapace  folded,  univalved  and  rostrate. 

Family  1.     Nebaliidae  Baird. 

Cephalic  appendages  five,  thoracic  eight,  abdominal  eight,  terminating  in  two  caudal 
spines.     No  metamorphosis ;  development  direct. 

Nebalia   Leach   (Fig.    1452).     Represented  by  a  few   marine   species  inhabiting 
shallow  waters.     Paranebalia  and  Nebaliopsis  are  also  Recent  and  marine. 

Akad.  Wissens.,  1885. Ibid.,  1886. — On  Occurrence  of  a  New  Form  of  Discinocaris  inBohemia. 

Geol.  Mag.,  1892,  dec,  3,  vol.  ix. — Sars,  O.  0.,  Report  on  the  Phyllocarida  (Leptostraca).  Rept. 
Challenger 'Expedition,  1887,  vol.  ^ix.—Hall,  J.  and  Clarke,  J.  M.,  Palaeontology  of  New  York, 

1888,  vol.  vii. Whitjleld,  R.  F.,  New  Genus  of  Phyllocaridae.     Bull.   Ainer.  Mus.   Nat.  Hist., 

1896^  vol.  \\\(.— Jones,  T.  R.,  and  Woodward,  IL,  Mouograph  of  the  British  Palaeozoic  Phyllopoda 
(Phyllocarida,  Packard),  Part  iii.  Palaeontogr.  Soc,  1898.— C/a?7.r,  /.  M.,  Some  Devonic  and 
Siluric  Phyllocarida  from  New  York.  54th  Ann.  Rept.  N.Y.  State  Mus.,  1900  {1902).  — WaJcott, 
C.  D.  Middle  Cambrian  Branchiopoda,  Malacostraca,  Trilobita  and  Merostomata.  Smithson, 
Mise.  Coli.  1912,  vol.  Ivii.  No.  6. 


750 


ARTHROPODA  phylum  vii 

Suborder  B.     HYMENOCARINA  Clarke. 

Nebalia-like  forms  with  folded  univalved  carapace ;  rostrum  loanting  {T). 

Family  1.     Hymenocaridae  Salter. 

Body  with  eight  to  nine  thoracic  and  abdominal  segments,  and  six  caudal  spines  in 
three  pairs. 

Hymenocaris  Salter  (Fig.  1453).  Carapace  narrow  in  front,  very  broad  posteriorly, 
convcx  ;  >nrface  smooth  or  faintly  lined.     Cambrian  ;  Wales  and  British  Columbia. 


Fig.  1452. 
Nebalia  geoffroyi  M.  Edw.    Recent ;  Mediterraneaii.    s/j. 


Fig.  1453, 


Hymenocaris  vermicauda  Salter. 
Upper  Cambriau  ;  Dolgelly,  Wales. 
Vi  (after  Salter). 


Several  peciüiar  genera  described  by  Walcott  under  the  names  of  Hurdia,  Tuzoia, 
Odaraittj  Fieldia  and  Garnarvonia,  from  the  Middle  Cambrian  of  British  Columbia, 
are  doubtfiilly  referred  to  this  family. 

Suborder  C.     CERATIOCARINA  Clarke. 

Carapace  hivalved,  with  a  median  Symphysis  and  a  free  rostrum. 


Family  1.     Oeratiocaridae  Salter. 
Carapace  pod-shaped,  smooth  and  without  eye-nodes. 

Ceratiocaris  M'Coy  {Entomocaris  Whitf.)  (Fig.  1454).     Valves  of  carapace  elongate, 
^^^^^^s^^^^^^^^^-^s^r^'^'-^^  sub-ovate  or  sub-quadrate, 

narrow  in  front,  sub- 
truncate,  but  not  in- 
■^  curved  iDehind.  Surface 
without  nodes  or  carinae. 
Antennae  (?)  obscure;  sup- 
posed  gastric  teeth  large, 
cuspidate.  Rostrum 
lanceolate.  Body  Seg- 
ments fourteen  or  more, 
four  to  seven  extending 

-  ■         '   ot     them    with     obscure 


Fig.  1454. 


n.an.lil.les  ;    ,,   Rostral  plate.      lA^gfter 


branchial      appendages 


SUßCLASS  II 


EUCRUSTACEA— PHYLLOCARIDA 


751 


Cardiolites  Nich.     Supposed  tracks  of  Geratiocaris  (?).     Silurian  ;  Scotland. 

Garyocaris  Salter.  Carapace  smooth,  narrow,  sub-acute  in  front,  thick.  Abdomen 
unknown  ;  caudal  plate  with  three  spines.     Cambrian  ;  Wales. 

Physocaris  Salter.  Carapace  bladder-sliaped,  pointed  in  front,  bivalved  (?),  smooth. 
Abdomen  smooth  ;  telson  longer  than  the  cercopods.     Silurian. 

Lingulocaris,  Saccocaris  Salter.  Very  imperfect  remains  of  Crustacean  bodies. 
Lingula  Flags ;  Wales. 

Acanthocaris  Peacli.  Carapace  small,  with  a  blunt  snoiit  in  front ;  surface  smooth. 
Body  Segments  numerous,  seven  exposed  beyond  the  carapace.  Telson  long  ;  cercopods 
short  or  rudimentarj.     Lower  Carboniferous  ;  Scotland. 

Xiphidiocaris  Jones  and  Woodw.  (emend.).  Known  only  by  its  long  curved  blade- 
like  telson.     Silurian  (Ludlow) ;  England.     (X.  ensis  Salter.) 

Gryptozoe  Packard.  Carapace  smooth,  broadly  rounded  in  front ;  imperfectly 
known.  Coal  Measures  ;  Illinois,  (C.  problematicus  Packard).  Probably  congeneric 
with  the  Carboniferous  species  named  Geratiocaris  oretonensis  and  G.  truncata  Woodw., 
in  which  traces  of  four  cephalic  appendages  liave  been  found. 

Golpocaris  Meek.  Carapace  smooth,  with  deep  anterior  marginal  sinus  and  sharp 
extremity.     Caudal  plate  with  three  spines.     Lower  Carboniferous  ;  Kentucky. 

Strigocaris  Vogdes    (Solenocaris    Meek).       Carapace  narrow    and    elongate,    with 
longitudinally    striated    surface ;    very    imperfectly    known. 
Lower  Carboniferous  ;  Kentucky. 

Nothozoe  Barrande.  Doubtfully  assigned  here.  Ordovi- 
cian ;  Bohemia. 

Phasganocaris  Novak.  Known  only  from  the  abdomen 
and  telson.  Last  segment  long,  cylindrical,  with  strong 
articulation.  Telson  articulated  to  the  cercopods  by  deep 
sockets ;  edges  spinöse.  Surface  scaly.  Lower  Devonian  ; 
Bohemia. 

Macrocaris  Miller.  Carapace  valves  very  narrow  in 
front,  broad  behind,  strongly  lineate.  Body  segments 
numerous.      Lower  Carboniferous  ;  Kentucky. 

Family  2.     Echinocaridae  Clarke. 

Garapace  elongate  or  oval,  with  nodes  (muscular  or  seg- 
mental) in  the  cephalic  region,  one  of  ivhich  in  each  valve 
may  he  ocular  hut   hears  no  optic  pit ;    one  or  more  lateral 

carinae     usually    present. 

A   free  rostrum  has  been 

ohserved  in  some  genera. 

Echinocaris  Whitf. 
(Figs.  1451, 1455).  Hinge 
short,   carapace  sub-oval,  Fig.  1455. 

broad  in  front,  not  in-  EcUnocaHs  punctata  (Hall), 
curved  behind  nonn^tprn  Hamilton  Group ;  Pratt's  Falls, 
curveu  uenma,  no  postero-    ^^^^  york.    %  (after  Beecher). 

lateral  spinules  ;    a  single 

sigmoid  carina  on  each  valve,  sometimes  a  small 
accessory  ridge  near  the  hinge.  Surface  punctate 
and  pustulose,  no  longitudinal  striations.  Of  the 
body  Segments,  six  are  exposed  and  bear  small 
spines  on  their  surface  and  posterior  margins. 
Pephricarishorriinlata  ci&rk^.  Cheiiiung   Telson   and   cercopods  are  spines  of  unequal  size. 

Group;    Alfred,    New    York       Vi    (after    ■.-r-jji  i   tt  ^  •  -..-r       ,      .     ^    . 

Clarke).  Middle  and  Upper  Devonian  ;  North  America. 


Fig.  1456. 


762 


ARTHROPODA  phylum  vii 


Pephricaris  Clarke  (Fig.  1456).  Carapace  as  in  the  last,  but  without  the  lateral 
carinae.  Margins  provided  with  a  single  row  of  long  recurving  spines.  Three  or 
four  abdominal  segments  protrude  beyond  the  carapace,  the  last  two  having  a  single 
pair  of  long  spines.     Upper  Devonian  ;  New  York. 

Aristozoe  Barr.  (Bactropus  Barr.).  Carapace  with  cephalic  node  well  developed, 
but  without  lateral  carinae.  But  one  abdominal  segment  known,  and  this  is  very 
long,  cylindrical,  with  an  intricate  hinge  at  the  articulation  with  the  caudal  spines. 
Telson  a  long  spine  with  a  row  of  spinules  on  each  lateral  edge.  Noväk  has  shown 
that  of  Barrande's  three  species,  Aristozoe  regina,  Bactropus  longipes  and  Geratiocaris 
deUlis,  the  first  represents  the  carapace,  the  second  the  last  abdominal  segment,  and 
the  third  the  telson  of  one  form,  A.  regina.  Devonian  ;  Bohemia.  Species  referred 
to  the  same  genus  have  been  described  from  the  Cambrian  of  North  America  and 
Devonian  of  Germany  and  Russia. 

Orozoe  and  Callizoe  Barrande  are  presumably  allied  to  Aristozoe.  Silurian ; 
Bohemia.     Zonozoe  Barr,  and  Solenocaris  Young  are  not  Crustaceans. 

Eleutherocaris  Clarke.  Carapace  elongate-subquadrate,  truncate  in  front,  incurved 
behind ;  rostrate  (?).  Broad,  obscure  nodes  in  the  cephalic  region  ;  lateral  carinae 
Single,  anterior  and  very  short.  Body  segments  unknown ;  caudal  plate  with  a 
slender  telson  and  cercopods  of  equal  length.  Surface  pf  all  known  parts  more  or  less 
ßtrongly  tuberculated.     Upper  Devonian  ;  New  York. 

Ptychocaris  Noväk.  Valves  elongate-subquadrate,  posterior  margin  sloping  or 
slightly  incurved.  Cephalic  region  with  a  Cluster  of  small  nodes  in  front,  and  two 
larger  nodes  behind.  Lateral  region  with  a  single  long  sigmoid  carina.  Surface 
striated  with  raised  longitudinal  lines.  Abdomen  and  tail  unknown.  Lower 
Devonian ;  Bohemia. 

Elymocaris  Beecher.  Surface  of  carapace  evenly  convex,  smooth,  without  lateral 
carina ;  hinge  line  long ;  posterior  margin  convex ;  cephalic 
nodes  obscure  ;  rostrum  not  observed.  Abdomen  with  two  ex- 
posed  segments ;  caudal  plate  short,  with  broad  convex,  rapidly 
tapering  telson  and  two  cercopods,  setigerous  on  their  inner 
margins.  Middle  Devonian;  New  York.  Upper  Devonian; 
Pennsylvania. 

Tropidocaris  Beecher  (Fig.  1457).  Carapace  with  truncate 
posterior  margins;  ocular  node  well  defined,  other  cephalic 
nodes  obscure;  rostrum  narrow  and  ridged ;  surface  of  valves 
Tropiöocaris  ,üuriru.ta  ^IT"^^  '^T^  longitudinal  carinae.  Abdomen  with  two 
Beecher.  Chemung  exposed  Segments,  which  are  sub- cylindrical  and  without 
ÄLandToTtrum'""/;   'Pf^^'^'      ^P?^^  Devonian  and  Lower  Carboniferous ;    Penn- 

(after  Hall  and  Clarke).        Sylvania. 

,  ..V  ^.  .  ^'^'^'^^^oe  Jones  and  Woodw.  Valves  of  carapace  elongate, 
narrow,  and  with  distinct  ocular  node;  other  cephalic  nodes  wanting.  Surface  tith 
fine  longitudinal  raised  Striae.     Abdomen  unknown.     Silurian. 

Suborder  D.     RHINOCARINA  Clarke. 

Family  1.     Rhinocaridae  Clarke. 

rosierior  margin  of  carapace  concave  and  spined. 


SUBCLASS  II 


EUCRUSTACEA— PHYLLOCARIDA 


753 


Rhinocaris  Clarke  (Fig.  1458).  Carapace  smooth,  with  fiiie  raised  longitudinal 
Striae ;  divergent,  branchiiig  furrows  radiating  backward  from  the  eyes.  Lateral 
cariiia  very  faint.  Abdomen  with  two  or  three  free  segments,  the  last  much  longer 
than  the  others ;    all  diagonally  striated  or  chevroned.     Caudal  plate  with  a  broad 


Fig.  1458. 

Rhinocaris  coluvibina  Clarke.  Ham- 
ilton Group ;  Canandaigua  Lake,  New 
York.  A,  E,  Dorsal  and  lateral  views  of 
animal.  B,  D,  Same  of  rostrum,  en- 
larged.     C,  Median  plate,  enlarged. 


Fig.  1459  bis. 

Mesothyra  oceani  Hall.  Portage  Group 
(Upper  Devonian) ;  Ithaca,  New  York.  A, 
Eye.    B,  Hinge  of  right  valve.    i/i. 


Fig.  1459. 

Mesothyra  oceani  Hall.  Upper  Devonian ;  New 
York.  Reconstruction  of  carapace  and  abdonien. 
1/2  (after  Hall  and  Clarke). 


telson  and   two  long  and  slender  cercopods  fimbriated   on   their   margins.     Middle 
Devonian ;  New  York. 

Mesothyra  Hall  and  Clarke  (Fig.  1459).  Carapace  large,  valves  distinctly  inter- 
locking  at  point  of  contact.  Lateral  carinae  strong,  crenulated  at  the  summit. 
Abdomen  with  two  broad,  exposed  Segments.  Telson  shorter  than  the  cercopods, 
the  latter  setigerous.     Upper  Devonian  ;  New  York. 


Dithyrocaris  Scouler  {Ar gas  Scouler).  Very  similar  in  aspect  to  Mesothyra^ 
with  the  junction  line  of  the  valves  overlapped  by  a  (free  ?)  rugose  ridge  or  narrow 
interstitial  plate.  Rostrum  not  observed.  Devonian  and  Carboniferous ;  Scotland. 
Rachura  Scudder,  known  only  from  the  abdomen  and  telson,  is  probably  allied  to 
Dithyrocaris.     Carboniferous ;  Illinois. 

Ghaenocaris  Jones  and  W.  Carapace  valves  with  a  very  strong  lateral  ridge  and 
without  posterior  spine.      Carboniferous  ;  Scotland  and  Belgium. 


VOL.  I 


3c 


754 


ARTHROPODA 


PHYLUM  VII 


Suborder  E.     DISCINOCARINA  Clarke. 


Sub-circular  or  oval  shields  with  a  triangulär  rostrum  filling  an  anterior  notch. 
Sarface  ornamented  loith  raised  concentric  lines.     Suhstance  chitinous. 

Family  1.     Discinocaridae  Woodward. 


Test  convex,  sometimes  mesially  ridyed ;  m  a  smgle  piece. 

Discinocaris  AVoodw.  Shield  sub-circular,  rostral  notch  and  rostrum  angulai. 
Abdominal  segments  and  caudal  spines  have  been  referred  to  this 
genus  by  Jones  and  Woodward.  Silurian ;  Great  Britain, 
Bohemia. 

Aspidocaris  Reuss.  Similar  to  Discinocaris,  Raibl  Bedt^ 
(Upper  Trias) ;  Hallstadt. 

Dipterocaris  Clarke  (Fig.  1460).  Shield  with  a  deep  posterior 
notch,  shorter  than  the  anterior  or  rostral  notch.  Sides  of  shield 
sloping.     Silurian  ;  Scotland.      Upper  Devonian  ;  New  York. 


Fig.  1460. 

Dipterocaris  rctustm 
d'Arch.  and  Vern.  De- 
vonian ;  Bifel.     Vi- 


Family  2.     Peltocaridae  Salter. 

Shields  mesially  sutured. 

Peltocaris  Salter.     Circular   shields   with    a  rounded    rostral    notch    and    plate. 
Abdomen  unknown.     Ordovician  ;  Great  Britain. 

Aptychopsis  Barr.  (Fig.  1461).     Like  Peltocaris,  but  with  the 
rostral  notch  angular.     Silurian  ;  Bohemia  and  Great  Britain. 

Pinnocaris  Etheridge.     Similar  to  Dipterocaris,  but  bivalved. 
Ordovician  ;  Scotland.      (P.  lapworfhi  Etheridge  jun.) 


Addendum. 


Fi<i.  1461. 

Aptychopsis  primus 
Barr.  Ordovician  (D) ; 
Branik,    Bohemia.      i/i 

A  iiumber  of  generic  names,  such  as  Gardiocaris  (Fig.  1462), 

Ellipsocaris,    Pholadocaris   Wood  ward,    and    Spathiocaris    Clarke, 

have  been  applied  to  Devonian  fossils  which  closely  resemble  the 

Silurian  Discinocaris,  of  whose  Crustacean  nature  there  seems  to 

be  no  doubt.     Some  of  these  bodies,  however  (Gardiocaris),  have 

been  found  in  the  living  Chamber  of  Goniatites  (G.  intumescens), 

and  have  undoubtedly  served    as  opercula  or  aptychi   of   these 

Cephalopods;    of   others    the    nature    is    not    fully  understood. 

Lisgocaris  Clarke  is  not  a  Crustacean;    Gryptocaris  Barrande  is 

Fio.  1462.  probably   the  operculum    of   a    Hyolithoid  ;    Myocaris    Salter    is 

(■urdioturis  (Anapty-  stated    to   be  a    Pelecypod ;    Proricaris    Baily    was    founded    on 

tvvlv'^i'^y'^ni^n]  P*^^«   of  Geratiocaris ;    Grescentilla   and   Pterocaris  Barrande   are 

Bttdeslieini,  Eitel.    Vi-    doubtfully  Crustacean. 

Series  II.    EUMALAOOSTRAOA  Grobben. 

Abdomen  of  six  somites,  all  of  which  may  hear  appendages,  and  a  telson  which 
never  bears  movable  furcal  rami  Thoracic  limbs  rarely  all  similar,  typically 
pediform.  ^  ^    jr       j 

The  remains  of  Crustacea  presenting  the  primitive  "caridoid  facies,"  as 
described  above  occur  in  the  Carboniferous,  and  it  may  be  that  the  Eumala- 
costraca   had   their   origin  in   that  epocli.     If    certain   Devonian  fossils   are 


SUBCLASS  II 


EUCRUSTACEA— SYNCAKIDA 


•765 


correctly  assigned  to  the   Isopoda,  however,  the  origin   of    the  series  must 
have  been  considerably  earlier, 

Division  A.     SYNCARIDA  Packard.^ 


VIII 


Order.     ANASPIDACEA  Calman. 

Carapace  absent.     First  thoracic  somite  fused  with  the  headj  or  defined  therefrom 
hy    a    groove.      Eyes    pedunculate    or 
sessile.      Thoracic   legs   typically    with 
exopodites  ;  no  oostegites.  ,  Uropods  and 
telson  forming  a  tail-fan. 

The  name  Syn- 
carida  was  applied 
hy  Packard  to  a 
group  of  Carboni- 
ferous  and  Per- 
mian  Crustacea  of 
which  the  affinities 
long  remained  ob- 
scure.      The    dis- 


covery,      in 


Anaspides  tasmaniae  Thomson. 


Fig.  1463. 
Recent ;  Tasmania. 


groove    ;  ii,  viii,  Second  and  eighth  thoracic  somites 
dominal  somites  (after  Calman). 


Male, 

;  1,  6, 


>/i.    c.gr,  "Cervical 
First  and  sixth  ab- 


the 
fresh  waters  of 
Tasmania  and 
Australia,  of  living  forms  with  similar  characters  has  thrown  a  new  light  on 

Ä  .  B 


Fig.  14Ö4 


l'alueocaris  typua  Meek  and  Worthen.     Goal  Measures  ;  Illinois.     A,  Restoration  of  body,  omitting  eyes,  4/^. 
B,  Telson  and  uropods,  6/^  (after  Packard). 

the  subject,  and  reinvestigation  of  some  of  the  fossils  has  only  emphasised 
their  close  agreement  with  the  Recent  Anaspides  (Fig.  1463)  and  its  allies. 
Of    the   fossil   genera,    Palaeocaris    Meek   and    Worthen    (Fraeanaspides 

1  Literature :  Jordan,  H. ,  and  Meyer,  H.  von,  Crustaceen  der  Steinkohlenformation  von 
Saarbrücken.  Palaeontogr. ,  1854,  vol.  iv. — Brocchi,  P.,  Note  sur  un  Crustace,  etc.  Bnll.  See. 
Geol.  France,  1880,  ser.  3,  vol.  viii. — Fackard,  A.  S.,  On  the  Syncarida,  etc.  Mem.  Nat.  Acad. 
Sei.  Washington,  1886,  vol.  iii. — Thomson,  G.  M.,  On  a  fresh  water  Schizopod  from  Tasmania. 
Trans.  Linn.  Soc.  London  (2)  Zool.,  vi.,  1894. — Calman,  W.  T.,  On  the  Genus  Anaspides,  etc. 
Trans.  Koy.  Soc.  Edinburgh,  1896,  vol.  xxxviii.,  pt.  iv. — On  Pleurocaris,  etc.  Geol.  Mag., 
1911,  dec.  5,  vol.  viii. — Fritsch,  A.,  Fauna  der  Gaskohle,  1901,  vol.  iv.,  Heft  3,  Crustacea,  etc. 
—  Woodward,  H.,  Some  Coal-measure  Crustaceans,  etc.  Geol.  Mag.,  1908,  dec.  5,  vol.  v. — 
Sayce,  0.  A.,  On  Koonunga  cursor,  etc.  Trans.  Linn.  Soc.  London  (2)  Zool.,  xi.,  1908. — 
Smith,  G.,  On  the  Anaspidacea,  living  and  fossil.     Quart.  Journ.  Microsc.  Sei.,  1909,  vol.  liii. 


756 


ARTHROPODA 


PHYLÜM  VII 


Woodward)  (Fig.  1464),  froni  the  Goal  Measures  of  England  and  North 
America,  is  now  the  most  completely  known.  It  resembles  Anaspides  in 
general  form,  in  the  segmentation  of  the  body,  the  pedunculated  eyes,  the 
characters  of  antenniiles,  antennae,  and  even  of  the  minute  mouth-parts^  the 
exopodites  of  the  thoracic  legs,  and  the  form  of  the  tail-fan.  The  only 
important  difFerence  between  the  two,  apart  from  the  delicate  lamellar  gills 
which  could  hardly  be  looked  for  in  a  fossil,  is  the  presence  in  Falaeocaris  of 
a  wedge-shaped  first  thoracic  somite,  which,  in  Anaspides,  is  fused  with  the 

head. 

Uronectes  Bronn  (Gampsonyx  Jordan  and  v.  Meyer)  (Fig.  1465),  from  the 
Lower   Permian    of    Saarbrücken,   resembles   Falaeocaris, 
but  has  one  of  the  anterior  pairs  of   legs  enlarged  and 
armed     with     spines.        Acanthotelson 
Meek    and    Worthen,    and    Pleurocaris 
Calman,   from    the   Goal   Measures    of 
Illinois   and  of    England   respectively, 
have    the  first    thoracic    somite  fused 
with  the  head  and  may  perhaps  have 
no    thoracic    exopodites.     These    exo- 
podites are  also  stated  to  be  absent  in 
Gasocaris   Fritsch,    from    the    Permian 
Gaskohle    of  Bohemia.      Palaeorchestia 
Zittel     (Fig.  .  1466)     and     Neäotelson 
(FSr''''coarMeai"  ^^occhi,    are  less    completely   known, 
-es ;  Lisek,  near  Beraun,  and   are    doubtfullv   included    in  this 

ohemia.      i/^   (after 


Fio.  1465. 


Fig.  1466. 


Uronectes  fimbriatus 
(Jordan).  Rothlie- 
gendes ;  Lebach,  Saxony. 
V,. 


ures ; 
Bc 


Fritsch). 


group. 


Division  B.     PERACARIDA  Calman. 

Carapace,  when  present,  leaving  at  hast  four  of  the  thoracic  somites  distinct  ; 
first  thoracic  somite  always  fused  with  the  head.  Eyes  pedunculate  or  sessile. 
Oostegites  attached  to  some  or  all  of  the  thoracic  limbs  in  the  female,  forming  a  hrood- 
pouch. 

Of  the  Orders  included  in  this  division,  two,  the  Cumacea  and  Tanaidacea 
are  unrepresented  in  the  fossil  state. 


Order  1.     MYSIDACBA  Boas.i 


I 


The  caridoid  fades  is  retained.  The  carapace  extends  over  the  greater  part  of 
the  thoracic  regton,  but  does  not  coalesce  dorsally  with  more  than  three  of  the  thoracic 
somites. 

Among  the  caridoid  forms  known  from  Carboniferous  rocks,  PygocephaUs 
Huxley,   from   the   Engl.sh   Goal   Measures,   has   recently  been   shown   by 

gSi 'so      1861  7of  iSi      «,;■    /*''''/™„''''°*^''  ''■'""  B""«''  Goal  Meas„re.s.     Q,,art.  Journ 
Sand    '  /^ISs  K  vnx5ÄJ«;„°TTTh°^^  '"  Carloniferous  „f 

A,ner.  Journ.  Sei.,  1897,  ser.  4,  vö  .  iv -S,trrö'/?    0^^!t™*°  P°„""""  °f  ^''«S"*^.  '^■ 
Mer,,  1907  ,lec   S  vol  iv  —P„irhn\r    L""*""™;  "■'  On  the  genus  Pygocepludm,  etc.     Geol. 

of  l^oUand.     Men;.te„i:-S^^!t;eatB*kta° "fSs''  °"  ''*'■'''  °™^*»"^^°f  Carboniferous  Rocks 


I 


SÜBCLASS  II 


EUCRUSTACEA— PERACAEIDA 


757 


Fig.  1467. 


H.    Woodwtird    to   possess   a  brood-pouch   formed   of   overlapping  oostegites, 

and    may    therefore    be    referred,    with    little    doubt,    to    the    Mysidacea. 

Crangopsis  Salter,  from  the  Lower  Carboniferous 

of    Scotland   and    the    base    of    the    VVaverly    in 

Kentucky  is    placed    here    by   Ortmann,  since  it 

has  the  posterior  thoracic  somites  distinct  beneath 

the  carapace.     Anthrapalaemon  Salter  (Fig.  1467), 

Pseudogalathea,  Tealliocaris,  and  Palaemysis  Peach, 

all  from  the  Carboniferous,  have  also  been  referred 

to  this  Order. 

Order  4.     ISOPODA  Latreille.i 

Body  usually  hroad  and  dep-essed.  Carapace 
absent ;  first  thoracic  somite,  rarely  also  the  second, 
fused  with  the  head.  Abdomen  short,  the  last  somite 
almost  always  coalesced  with  the  telson.  Eyes  sessile. 
Thoracic  limbs  without  exopodites.  Abdominal  limbs 
lamellar,  branchial.  ,  ,,      ,  •,.  ,c     ^w 

'  Anthrapalaemon  gracilis  M.  and  W. 

Of  the  earlier  fossils  that  have  been  referred  ?£.  .ATXr»ieä"a°ntwor*™r' 
to   this   Order,    Oxyuropoda  Carpenter   and   Swain 

(Fig.  1468),  from  the  Devonian  of  Ireland, 
has  the  strongest  claim  to  be  regarded 
as    an    Isopod.      Its    appearance    earlier 

^  Literature :  A.  On  Recent  Forms.  —  Beddard, 
F.  E. ,  Report  on  the  Isopoda.  Sei.  Resiilts  Challenger 
Exped.,  Zool.,  xL,  \^Sh.— Hansen,  H.  /.,  Isopoden, 
Cumaceen  und  Stomatopoden  der  Plankton-Expedition. 
Ergebn.  Plankton- Exped.,  ii.,  1895.— /^ew,  On  the 
Family  Sphaeromidae.  Quart.  Journ.  Microsc.  Sei., 
1905,  n.s.  vol.  xlix. — Miers,  E.  /.,  Revision  of  the 
Idoteidae.  Journ.  Linn.  Soc.  London,  1883,  vol.  xvi. 
— Richardson,  H. ,  Monograph  on  the  Isopods  of  North 
America.  Bull.  U.S.  Nat.  Mus.,  1905,  vol.  liv.— 
Sars,  G.  0.,  An  aecount  of  the  Crustacea  of  Norway, 
vol.  ii.     Isopoda.     Bergen,  1896-99. 

B.  On  Fossil  Forms. — Ammon,  L.  von,  Beitrag  zur 
Kenntniss  der  fossilen  Asseln.  Sitzungsber.  Bayer. 
Akad.  Wiss.,  1?>%2.—Andree,  K.,  Zur  Kenntniss  der 
Crustaeeen-Gattung  Arthropleura  Jordan.  Palaeontogr., 
1910,  vol.  Ivii.— Carter,  /.,  On  fossil  Isopods.  Geol. 
Mag.,  1889,  dec.  3,  vol.  vi. — Edwards,  H.  Milne,  Sur 
deux  crustaces  fossiles.  Ann.  Sei.  Nat.  Zool.,  1843, 
ser.  2,  vol.  xx. — Idem,  On  Archaeouiscus.  Ann.  Mag. 
Nat.  Hist.,  1844,  ser.  2,  vol.  xm.—Kunth,  A., 
Crustaceen  von  Solenhofen.  Zeitschr.  Deutsch.  Geol. 
Ges.,  1870,  vol.  xx\\.— Meyer,  H.  von,  Ueber  Palaeo- 
niscus  obtusus.  Palaeontogr.,  1858,  vol.  v. — Racovitza, 
E.  G.,  and  Sevastos,  R.,  Proidotea  haugi,  n.g.,  n.sp., 
etc.  Arch.  Zool.  Exper.  Paris,  1910,  ser.  5,  vol.  vi.— 
Reines,  M.,  tJber  Palaeosphaeroma  tihligi,  etc.  Beitr. 
Paläont.  Geol.  Österr.  -  Ungarn,  1903,  vol.  xv.— 
Woodward,  H.,  Several  papers  in  Trans.  Woolhope 
Field  Club,  1870  ;  Geol.  Mag.,  1870,  dec.  1,  vol.  vii.  ; 
1890,  dec.  3,  vol.  vii.  ;  1898,  dec.  4,  vol.  \.—Idem, 
On  Squilla,  etc.  Quart.  Journ.  Geol.  Soc,  1879,  vol. 
XXXV. — Carpenter  G.  H.,  and  Sioain,  /.,  A  Devonian 
Isopod.     Proc.  Roy.  Irish  Acad.,  1908,  vol.  xxvii. 


Fio.  1468. 

Oxyuropoda  ligioüles  Carp.  and  Swain.  Upper 
Cid  Red  Sand.stone  ;  Kiltorcan,  Ireland.  a, 
Portion  of  antenna ;  c,  Chela  (?) ;  o,  Eye  ;  p, 
Segment  of  body-limb  ;  u,  Uropod  ;  1-7, 
Thoracic  segments  ;  i.-vi.,  Abdominal  segments. 
Vi  (after  Carpenter  and  Swain). 


758 


ARTHROPODA 


PHYLÜM  VII 


than  the  primitive  caridoid  forms  may,  however,  justify  some  suspicion  as 
to  it-s  affinities.  Fraearcturus  Woodward,  from  the  Old  Red  Sandstone  of 
Herefordshire,  has  very  slender  claims  to  be  admitted  into 
this  Order,  and  the  same  may  be  said  of  Amphipeltis  Salter 
(Devonian  of  Nova  Scotia),  and  Arthropleura  Jordan  (Goal 
Measures). 

Undoubted  Isopods  appear  in  Secondary  rocks.  Urda 
Münster  (Fig.  1469),  from  the  Kimmeridgian  of  Solenhofen, 
has  some  very  peculiar  characters  in  which  it  approaches 
the  males  of  the  Recent  Gnathia,  differing,  however,  in  the 
large  size  of  the  eyes.  Cyclo sphaeroma  Woodward,  from  the 
Great  Oolite  and  Purbeck,  resembles  in  general  form  some 
Recent  members  of  the  family  Sphaeromidae,  as  do  also 
Archaeoniscus  Milne  Edwards  (Fig.  1470),  from  the  English 
Purbeck  and  JEosphaeroma  Wood  ward  (Fig.  1471),  from  the 
Eocene  and  Miocene.  Palaega  Woodward  (Fig.  1472), 
Cenomanian  and  Oligocene,  has  a  general  resemblance  to 
the  Recent  Aega  and  allied  genera.     Proidotea  Racovitza  and  Sevastos,  from 


Fig.  1469. 

Urda  rostrata  Miüist. 
Lithogiaphic  Stone  ; 
Solenhofen,  Bavaria, 
Vi  (after  Kunth). 


Fro.  1470. 

A ,  Archaeoniscus  brodei 
M.  Edw.  Purbeck  ;  Vale 
of  Wardour,  Wiltshire.  3/ 
(after  Wootlward).  ß,  Frag- 
ment of  inatrix.  i/,  (after 
Quenstedt). 


Fig.  1471. 

A,  Eosphaeroma  hrongniarti 
M.  Edw.  Middle  Oligocene  ; 
Butte  de  Chaumont,  near 
Paris.  3/1  (after  Woodward). 
B  Fragment  of  matrix.  i/i 
(after  Quenstedt). 


Fig.  1472. 

Palaega  scrobiculata  (v. 
Ammon).  Lower  Oligo- 
cene ;  Haring,  Tyrol.  an, 
Antennae  ;  0,  Eyes  ;  jß, 
Uropod ;  I-Vll,  Thoracic 
Segments ;  1-6,  Abdominal 
Segments. 


Se^VaTvifera"'  Eoumania,  is  closely  allied  to  the  Recent  Mesidotea  in  th. 

Order  5.     AMPHIPODA  Latreille.i 

Body  usualhj  compre.sed  latendly.     Carapacs  absent ;  first  thoracic  somüe,  more 

•     •,  «  .italogue  of  the  Amplupoda  in  the  British  Museum,  1862. 


4 


suBCLASS  II  EUCRUSTACEA— EUCARIDA  759 

rarely  also  the  seconcl,  fused  with  the  head.  Abdomen  shorf,  ventrally  flexed,  the 
last  somite  usually  distinct.  Eyes  sessile.  Thoracic  limhs  ivithout  exopodites,  the 
basal  Segments  usually  lameUar,  carrying  gills.  Abdominal 
appendages  divided  into  two  sets,  the  last  three  pairs  directed 
backwards,  sfyliform. 

Although  various  Paleozoic  fossils  from  the  Silurian  ^     _, 

^  Fio   1473 

{Necrogammarus  Woodward)  and  later  rocks  have  been  Gammarus  oeningensis 
referred  to  this  order,  it  is  only  in  the  Tertiary  that  Heer.  Miocpiie ;  Oenin- 
undoubted  Amphipods  appear.  Some  of  these,  from  the  "  '  '  ^' 
Miocene,  are  referred  to  the  Recent  genus  Gammarus  Fabricius  (Fig.  1473), 
from  which  Palaeogammarus  Zaddach,  foiind  in  Baltic  amber,  is  doubtfully 
distinct. 

Division  C.     EUCARIDA  Oalman. 

Carapace  coalesced  dorsally  vnth  all  the  thoracic  somites.  Eyes  pediinculate, 
No  oostegites. 

Order  1.     EUPHAUSIACEA  Boas.i 

Caridoid  forms  in  which  none  of  the  thoracic  appendages  are  specialised  as 
maxillipeds  and  the  gills  are  in  a  Single  series  attached  to  the  bases  of  the  thoracic 
limbs. 

Anthracophausia  from  the  Calciferoiis  Sandstone  of  Scotland  is  described 
by  Peach  as  belonging  to  this  group,  but  the  points  of  resemblance  are  very 
slight. 

Order  2.     DBCAPODA  Latreille.^ 

The  caridoid  fades  may  be  retained  or  may  be  very  greatly  modified.  The  first 
three  pairs  of  thoracic  limbs  are  specialised  as  maxillipeds  and  one  or  more  of  the 

G.  0.,  An  account  of  the  Crustacea  of  Norway,  vol.  i,,  Amphipoda,  Christiana,  1890-95. — Stebbing, 
T.  R.  R.,  Report  on  the  Amphipoda,  Scient.  Resalts  Challenger  Exped.,  Zool.,  1888,  vol.  xxix. 
— Idem,  Gammaridea,  in  Das  Tierreich,  1906,  vol.  xxi. — Zaddach,  (7.,  Ein  Aniphipod  im  Bernstein. 
Schriften  physik. -Ökonom.  Ges.  Königsberg,  1864,  vol.  v, 

^  For  literature  references  see  under  the  head  of  Mysidacea. 

'^  Literature  :  A.  On  Recent  Forms. — Älcock,  A.,  Materials  for  a  carcinological  fauna  of  India, 
nos.  1-6.  Journ.  Asiatic  Soc.  Bengal,  1895-1900,  vols.  Ixiv.,  Ixv.,  Ixvii. -Ixix. — Idem,  Catalogues 
of  Calcutta  Museum,  1899-1910. — Bäte,  C.  S.  Report  on  the  Crustacea  Macrura.  Scient.  Results 
Challenger  Exped.,  Zool.,  1888,  vol.  xxiv. — Boas,  J.  E.  V.,  Studier  over  Decapodernes  Slaegtskabs- 
forhold.  Dansk.  Vidensk.  Selsk.  Skr.,  1880,  ser.  6,  vol.  i. — Borradaüe,  L.  A.,  Classification  of 
Decapod  Crustaceans.  Ann.  Mag..Nat.  Hist,,  1907,  ser.  7,  vol.  xix. — Bouvier,  E.  L.,  Sur  l'origine 
homarienne  des  Grabes.  Bull.  Soc.  I'hiloniath.,  Paris,  1896,  ser.  8,  vol.  viii. — Faxon,  W.,  Revision 
of  the  Astacidae.  Mem.  Mus.  Comp.  Zool.,  Cambridge,  188.5,  vol.  x. — Idem,  Stalk-eyed  Crustacea. 
Albatross  Reports,  xv.  Op.  dt.,  1895,  vol.  xviii, — Henderson,  J.  R.,  Report  on  the  Anomura. 
Scient.  Results  Challenger  Exped.,  Zool.,  1888,  vol.  xxvii. — Herrick,  F.  H.,  The  American  Lobster. 
Bull.  U.S.  Fish  Comm.,  1895,  and  Bull.  Bureau  Fisheries,  1911,  vol.  xxix.—Huxley,  T.  IL,  On  the 
Classification  and  Distribution  of  the  Craytishes.  Proc.  Zool.  Soc,  London,  1878. — Ortmann, 
A.  E.,  Die  Decapoden-Krebse  des  Strassburger  Museums.  Zool.  Jahrb.  Abth.  Syst.,  1890-94, 
vols.  v.-vii. — Idem,  Das  System  der  Decapoden-Krebse.  Op.  cü.,  1896,  vol.  xi. — Miers,  E.  J., 
Report  011  the  Brachyura.     Sei.  Results  Challenger  Exped.,  1886,  vol.  xvii. 

B.  On  Fossil  Forms. — Bell,  T.,  Monograph  of  the  fossil  Malacostracous  Crustacea  of  Great 
Britain.  Paleontogr.  Soc,  1857-62. — Bittner,  A.,  Brachyuren  des  vicentischen  Tertiärgebirges. 
Denkschr.  Akad.  Wiss.,  Wien,  1877-83,  vols.  xxxiv.,  xlvi.  —  Carter,  J.,  On  Orithopsis  honneyi. 
Geol.  Mag.,  1872,  dec  1,  vol.  ix. — Idem,  Contribution  to  the  palaeontology  of  the  Decapod  Crustacea 
of  England.  Quart.  Journ.  Geol.  Soc,  1898,  vol.  liv. — Cushman,  J.  A.,  Fossil  Crabs  of  the  Gay 
Head  Miocene.      Amer.   Nat.,  1905,  vol.   xxxix. — Etallon,  A.,  Description  des  crustaces  fossiles. 


ARTHROPODA  ^hylum  vii 

77 .  .h^inU      The  Ollis  are  typically  in  several  series  attached 

'^\^cl.^^CZ,lf^^^  forerunners  of  this  lavge  and  va.ied  order. 
Suborder  A.     NATANTIA  Boas. 

aMoul  Z2ch  Jdler  tLn  the  others.      Leg.  shnder,  someH^es  mlh  «opodtcs 
ttyoTe  oT'hTfirst  three  fain  r.ay  U  enUrged.     AMominal  affendages  ^ell  deveU^ed,^ 
used  for  swimming.     .  4 

bf  tlie  three  tribes  which  compose  this  suborder,  the  Penaeidea  ^näStenopidea' 
a»ree  in  having  the  fl..t  three  pairs  of  legs  chelate  (with  a  few  exoeptions  m  the 
P„««-«,a,/the  side-plates  „f  the  second  aHonunal  —  ^not  expand^d  ;  ^he. 

legs  is  mucli  larger  than  the 
first  in  the  Stenopidea,  but  not 
in  the  Penaeidea.  The  Caridea 
never  have  the  third  pair  of 
legs  chelate,  and  have  the 
side-plates  of  the  second  ab- 
dominal somite  expanded  to 
^  overlap  those  of  the  somites 

Fio.  1474.  in  front  and  behind. 

Peuaeus  meyeri  Oppel.    Upper  Jura  (Lithographie  Stone)  ;  The    Penaeidea   are   SOme- 

Solenhofen.    1/2.  ^j^^^   doubtfully  represented 

in  the  Trias,  but  a  long  series  of  fossils  from  the  Solenhofen  Lithographie  Stone  can 
be  referred  with  certainty  to  this  tribe.  Some  of  these  are  inchided  in  the  Kecent 
genus  Penaeus  Fabricius  (Fig.  1474),  while  Äcanthochirus  Oppel,  Bylgia,  Drohna  an^ 
Dusa  Münster  are  extinct  genera. 

The  Stenopidea   comprise  a  small  number  of  Recent  forms  which   show  some 

Bull.  Soc.  Geol.  France,  1859,  ser.  2,  vol.  xvu—Früsch,  Ä.,  Über  die  Caliaiiassen  der  böhmischen 
Kreide.    Abhandl.  Böhm.  Ges.  Wiss.,  1868,  vd.  \iy.— Knebel,  W.  von.  Die  Eryoniden  des  oberen 
Weissen  Jura  von  Süddeutschland.     Arch.  Biontol.,  1907,  vol.  ii. — Lörenthey,  K,  Über  die  Brachy- 
uren  der  paläont.  Sammlung  des  Bayer.  Staates  Termeszet  Füzetek,  Budapest,  1898,  vol.  xxi. — 
Idem,  Beiträge  zur  Decapodenfauna  des  ungarischen  Tfertiärs.       Math.-naturw.  Ber.   aus  Ungarn, 
1898,  1903,  vols.  xiv.,  xviii. — Idem,  Paläontol.  Studien  über  tertiären  Decapoden.     Op.  cit.,  1907, 
vol.  xxi. — Idem,  Beiträge  zur  tertiären  Decapodenfauna  Sardiniens  und  Ägyptens.      Op.  cit.,  1908, 
1909,  vols.   xxiv.,  XXV. — Mark,  W.  von  der,  Fossile  Fische,  Krebse  und  Pflanzen  aus  der  Kreide. 
Palaeontogr.,  1863,  vol.  xi. — Idem,  and  Schlüter,  C,  Neue  Fische  und  Krebse  aus  der  Kreide  von 
Westphalen.     Op.ciL,  1868,  vol.  xv. — Meyer,  H.  von,  Neue  Gattungen  fossiler  Krebse.    Stuttgart, 
1840. — Moericke,  W.,  Die  Crustaceen  der  Stramberger  Schichten.     Palaeontogr.,  1897,  Supplem. 
vol.  ii. — Oppel,  A.,  Ueber  jurassische  Crustaceen.     Palaeont.  Mittheil.  Mus.  Bayer.  Staates,  1862, 
vol.  ii. — Ortmann,  A.  E.,  On  Limiparus  in  the  Upper  Cretaceous  of  Dakota.     Anier.  Journ.  Sei., 
1897,  ser.  4,  vol.  iv. — Pilshry,  H.  A.,  Crustacea  of  the  Cretaceous   formation    of   New  Jersey. 
Proc.  Acad.  Nat.  Sei.  Philad.,  1901,  vol.  in.— Rathhun,  M.  J.,  Descriptions  of  fossil  crabs  from 
California.      Proc.    U.S.    Nat.   Mus.,   1908,   vol.  xxxv. — Schlüter,    C,    Die    Macruren-Decapoden 
Westphalens.     Zeitschr.  Deutsch.  Geol.  Ges.,  1862,  vol.  xiv.— Idem,  Kreide-  und  Tertiär-Krebse  des 
nördlichen     Deutschlands.     Op.     cit.,     1879,     vol.     xxxi. — Idem,    Podocrates     im     Senon     von 
Braunschweig.      Op.  cit.,   1899,  vol.  W.—Stimpson,     W.,   Fossil   Crab  from  Gay  Head.     Journ. 
Boston  Soc.   Nat.  Hist.,  1863,    vol.    vii. — Tribolet,  M.,  Descriptions    des    crustacees    du    terrain 
neocomien.     Bull.  Soc.  Geol.  France,  1874-75,  ser.  3,  vols.  ii.,  in.  —  Whitfield,  R.  F.,  American 
species  of /yo2?Zq/?aria.     Bull.  Anier.  Mus.  Nat.  Hist.,  1907,  vol.  xxiii.  — H^mÄ;Zer,  T.  C,  Etudes  sur 
les  genres  Pemphix,    Glyphaea,  etc.    Arch.  Mus.  Teyler,  1883,  ser.   2,  vol.  i.~Woodward,  H., 
Macrurous  Crustacea,  etc.     Quart.  Journ.  Geol.  Soc,  1872-76,  vols.  xxix.,  xxxii. 


SUBCLASS  II 


EÜCRUSTACEA— EUCARIDA 


761 


affinities  vvitli  the  Reptantia.  The  extinct  genus  Aeyer  (Fig.  1475),  whicli  has 
representatives  in  tlie  Trias  and  also  in  tlie  Solenliofen  Lithograjjliic  Stone,  agrees 
w'ith  the  Recent  genera  in  having  the  third  pair  of  legs  chelate  and  much  larger 
than  the  first.      It  is,  in  all  probability,  a  primitive  member  of  this  tribe. 

Representatives  of  the  Caridea  are  not  known  with  certainty  earlier  than  the 
Kinimeridgian,  though  some  Carboniferous  fossils  have  been  described  as  having  the 
enlarged  side-plates  of  the  second  abdominal  somite,  which  are  characteristic  of  this 
tribe.  In  the  Solenliofen  Stone  numerous  genera  occur,  some  of  which,  such  as  Udora 
Münster,  and  Udorella  Oppel,  have  exopodites  on  the  thoracic  legs,  a  primitive 
character  suggesting  affinity  with  the  Recent  family  Acanthephyridae.  Other 
Solenhofen  genera,  in  which  these  exopodites  appear    to   be  wanting,  are  Blaculla^ 


Fig.  1475. 
Aeger  tijndariiis  (Schloth.).     Upper  Jura  (Lithographie  Stone)  ;  Eichstädt,  Bavaria.     2/3. 

Hefriga  and  Eider  Münster.  The  Recent  deep-sea  genus  Oplophorus  Milne  Edwards 
(Acanthephyridae)  has  been  identified,  with  considerable  probability,  in  the  Upper 
Cretaceous  of  Westphalia.  Some  Caridea  are  found  in  fresh-water  Tertiary  deposits, 
as  for  example  Homelys  von  Meyer,  from  the  Miocene  of  Oeningen ;  but  it  is 
impossible  to  say  what  relation  they  bear  to  the  groups  of  Recent  Caridea  that  have  a 
fresh-water  habitat. 


Suborder  B.     REPTANTIA  Boas. 

Body  often  depressed,  rostrum  often  ahsent^  small  and  depressed  if  present.  First 
somite  qf  abdomen  distinctly  smaller  than  the  others.  Legs  stout,  without  exopodites, 
the  first  pair  usually  much  larger  than  the  others.  First  five  pairs  of  abdominal 
appendages  commonly  small,  not  used  for  swimming. 


§  1.  Palinura. 

This  section  consists  of  lobster-like  forms  with  the  rostrum  very  small  or  often 
absent,  with  the  carapace  fused  at  the  sides  with  the  epistome,  and  the  exopodite  of 
the  uropods  not  divided  by  a  distinct  suture.  It  includes  two  tribes  (1)  the  Eryonidea 
and  (2)  the  Scyllaridea  (or  Loricata). 

The  Eryonidea  comprise,  among  living  forms,  only  a  small  number  of  genera 
such  as  Polycheles  Heller,  and  Willemoesia  Grote,  which  have  chelae  on  the  first  four  or 


762 


ARTHROPOBA 


PHYLUM  VII 


■        f  u^      AU  are  blind  aud  inhabit  only  the  deep  sea      The  fossil 
on  all  live  pairs  of    e^.   /;"  *'^;   ^.^^  j,,  ^^allow  water  and  probably  poBsessed 


Fio.  1476. 
/w.von.  rrojdn'iuus  (Schlotli.)-     Lithographie  Stone  ;  Solenliofen ,  Bavaria.     I/o. 

Desmarest  (Fig.  1476),  of  whicli  finely  preserved  specimens  are  foimd  in  tlie  Upper 

Jurassic  Solenhofen  Stone,  ranges  from  tlie  Lias  (perliaps  the  Trias)  to  tlie  Neocomian. 

The  Scyllaridea,  which  are  distingiüshed,  among  other  characters,  by  liavmg  the 


Fic.  1477. 
Mecochiras  lojuiivMum  (tichloüi.).     Lithographie  Stone  ;  Eiehstädt,  Bavaria.     1/2- 

tirst  pair  of  legs  imperfectly  chelate,  include  the  Spiny  Lobsters  {Falinuridae) 
and  their  allies,  The  earlier  forms  should  probably  all  be  referred  to  the 
extinct  family  Glyphaeidae,  of  which,  the  first  representatives  occur  in  the  Trias. 
Pemphix  von  Meyer  (Fig.  1478)  occurs  in  the  Muschelkalk.  Lithogaster  and 
Glyphnea  von  Meyer  (Fig.   1479)  ränge  froni  Trias   to  Cretaceous.      Pseudoglyphaea 


SÜBCLASS  II 


EUCRUSTACEA— EUCARIDA 


763 


Oppel  is  Jurassic.      Scajjheus  and  Preatya  Woodward  are  Liassic.     Mecochirus  Kef. 

(Fig.    1477)  is   foimd  in  the   Middle  and  Upper  Jura,  and  Meyeria  M'Coy,  in  tlie 

Neocomian.  All  of  these  have  a  more  or  less 
distinct  rostruni  and  the  antennae  moderately 
developed. 

Palinurina  Münster,  froni  the  Lower  Lias  and 
Solenhofen  Stone,  appears  to  be  a  member  of  the 
Palinuridae,  a  family  which  has  the  rostriim  sup- 
pressed  and  the  antennae  very  stout.  Podocrates 
Geinitz,  from  Upper  Cretaceous  and  Eocene  is 
hardly  to  be  distinguished  from  the  Recent  Linu- 
parus  Gray.  Gancrinus  Münster,  from  Solenhofen, 
which  has  the  antennae  short  and  very  broad, 
perhaps  leads  toward  the  Scyllaridae,  in  which  the 
antennae  form  broad  flattened  plates.     Scyllaridia 


Fig.  1478. 

Pf.mphix  .t)imrii  Desm.     Muschelkalk  ;  Crailsheim, 
Würtemberg.     i/i. 


Fig.  1479. 
Glyphaea  tenuis  Oppel.  Lithographie  Stone  ; 
Eichstädt,  Bavaria.  A,  Side-view,  i/i-  ß,  Rostral 
region  enlarged.  a,  a",  First  and  second  pairs  of 
antennae ;  o,  Eye ;  s,  Antennal  scale ;  f<t,  Base  of 
second  pair  of  antennae. 


Bell  is  foLind  in  the  Gault  and  London  Clay,  while  the  Recent  Scyllarus  Fabr.  first 
appears  in  the  Chalk. 


§  2.  AsTACURA.     Lobsters  and  Crayfishes. 

This  section  comprises  only  the  tribe  Nephropsidea  (Astacidea)  including  the  true 
Lobsters  and  Crayfishes.  In  these,  the  rostrum  is  of  moderate  size,  the  carapace  is 
free  from  the  epistome,  and  the  exopodite  of  the  uropods  is  divided  by  a  suture. 
The  first  three  pairs  of  legs  are  chelate  and  the  first  pair  is  greatly  enlarged. 

The  earliest  member  of  this  groiip  is  Eryma  v.  Meyer  (Fig.  1480),  found  in  the 
Lias,  and  also  occurring,  together  with  Pseudoastacus,  Stenochirus  and  Etallonia  Oppel, 
in  the  Solenhofen  limestone.  Isolated  chelae  of  Magila  (Fig.  1481)  are  abundant 
throiighout  the  Jura.    Enoploclytia  M'Coy;  Nijmphaeops  Schlüter;  Oncoparia  Bosquet; 


ARTHROPODA 


PHYLÜM  VII 

-,  rr    7        •    M^nr^^r  nppnrin  tlieUDPei'Cretaceousof  Westplialia, 
Palaeastacus  Bell ;  and  H<^,lopar«,  M<.oy  omr  in  the  L  pp  ^    ^^  ^^^^^ 

lioliemia  and  England,  the  last-named  genus  also  ''-''''"^uUinDy,      the      Eecent 

geiiera  which    include   the 

Lübster/    the    Crayfish    of 

Eiirope,  and    the    Norway 

Fio.  1481.  Lobster  {Nephroms  of  Leach), 

Magih,  "  suwajurensis  have  beeil  stated  to   occiir 

(Quenstedt).  Upper  Jura;    ^^  e^rlv  as   the  Upper  Cre- 
Söflingen,      Würteinberg.  -^ 


d 


Chela. 


taceoiis. 


Fk;.  1482. 

Callianaffsa  arcUaci  M.  Edw.     Tnronian  ;  Montdragon, 

Var  (after  Milne  Edwards). 


Fia.  1480. 

Eryma  leptoiiactyliTia  (Germ.).  Litho- 
graphie Stone ;  Solenhofen,  Bavaria.  i/i 
(after  Oppel). 


Callimiassa  antiqua  Otto.     Turonian  ;  Turnau,  Bohemia. 
Eight  chela. 


§  3.  Anomura. 

This  section  includes  forms  which  have  the  abdomen  generally  soft  or  bent  upoii 
itself,  with  reduced  side-plates  and  tail-fan.  They  are  rare  as  fossils.  The  tribe 
Galatheidea  is  represented  only  by  chelae  from  the  Upper  Cretaceous  of  Denmark, 
referred  to  the  Recent  Galathea  Fabr.  Of  the  tribe  Thalassinidea,  the  Recent 
geniis  Gallianassa  Leach  (Figs.  1482,  1483)  is  known  from  the  Kimmeridgian,  as 
well  as  from  the  Cretaceous  and  Tertiary.  Thalassina  Latreille  is  Tertiary  and 
Recent.  The  tribe  Paguridea,  including  the  Hermit-crabs  and  their  allies,  is  very 
doubtfully  represented  in  the  Eocene  of  Hungary  by  chelae  referred  to  the  Recent 
Pagurus  Fabr.     The  Hippidea  are  unknown  in  the  fossil  state. 


§  4.  Brachyüra.     True  Crabs. 

The  true  Crabs  have  the  abdomen  small,  bent  under  the  thorax,  and  without  a 
tail-fan  ;  the  carapace  fused  with  the  epistome  at  the  sides  and  nearly  always  in  the 
middle  line  in  front ;  the  third  maxillipeds  more  or  less  broad  and  flattened,  covering 
the  other  mouth-parts. 

1  The  generic  name  Homarus  Milne  Edw.  is  most  commonly  used  for  the  Lobster,  and  Astacus 
Fabr.  for  the  Crayfish.  Some  writers,  however,  employ  Astacus  Fabr.  for  the  Lobster,  and 
PotainoUm  Leach  for  the  European  Crayfish.  The  questions  of  nomenclature  involved  cannot  suit- 
ably  be  discussed  here,  but  reference  may  be  made  to  a  recent  ruling  (1910)  of  the  International 
Commission  on  Zoological  Nomenclature. 


SUBCLASS  II 


EÜCßUSTACEA— EUCARIDA 


765 


The  Dromiacea  take  the  lowest  place  among  the  tribes  composing  this  section, 
differing  from  the  more  specialised  Brachyura  in  retainiiig  iiiany  primitive  characters. 
Thus,  the  last  somite  of  the  abdomen  often  retains  vestiges  of  uropods,  the  first 
abdominal  somite  of  the  female  has  a  pair  of  appendages,  the  fossettes  for  the  reception 
of  the  antennules  are  less  cleaiiy  defined,  and  the  gills  are  more  numeroiis. 

Among  the  Recent  Dromiacea,  again,  the  family  Homolodromiidae  is  the  most 
primitive,  its  members,  which  inhabit  the  deep  sea,  presenting  many  features  which 


C^^} 


Fig.  1484. 

A,  Prosopon  marginatum  v.  Meyer.  Upper  Jura  (e);  Oerlinger  Valley, 
near  Ulm.  s/g.  B,  P.  personatum.  Upper  Jura  (y) ;  Weissingen,  Würtem- 
berg.  Rostrum  enlarged.  C,  P.  amleatum  v.  Meyer.  Same  locality  as  A. 
D,  P,  pnstulaium  Quenst.     Same  locality  as  A. 


Fig.  1485. 

Dromiopsis  rugosa 
(Schloth.).  Uppermost  Cre- 
taceous ;  Faxoe,  Denmark, 


l^l  ' 


link  them  with  the  Lobsters  of  the  tribe  Nephropsidea.  It  is  therefore  of  special 
interest  to  find,  as  Bouvier  has  shown,  that  the  earliest  fossil  Brachyura,  forming  the 
extinct  family  Prosoponidae,  are  allied,  by  the  form  of  the  carapace  and  the  disposition 
of  the  grooves  upon  it,  to  the  existing  Homolodromiidae.  In  the  majority  of  cases 
the  carapace  alone  is  preserved,  but  portions  of  the  abdomen  and  limbs  are  known  in 
Protocarcinus  (Palaeinachus)  Woodward,  from  the  Forest  Marble  (Bathonian)  of 
England.  The  genus  Prosopon  von  Meyer  (Fig.  1484)  is  of  even  earlier  date, 
appearing  in  the  Bajocian  and  persisting  to  the  Neocomian.  Later  forms  approach 
more  specialised  Recent  types,  such  as  Homolopsis  Bell  from  the  Gault,  leading  towards 
the  Homolidae;  and  Dromiopsis  Reuss  (Fig.  1485),  leading  towards  the  Dromiidae. 
The  Tertiary  Dromilites  Milne  Edwards,  is  scarcely  different  from  the  Recent  Dromia. 
The  tribe  Oxystomata  is  characterised  by  the  form  of  the  mouth-frame,  which  is 
triangulär  and  produced  to  the  front  of  the  head  between  the  eyes.  The  earliest 
example  of  the  tribe  is  Mithracites  Gould, 
from  the  Lower  Greensand.  Palaeocorystes 
Bell  (Fig.  1486),  ranges  from  the  Gault 
to  the  Eocene.  Eucorystes  and  Necrocar- 
cinus  Bell  (Fig.  1487),  are  found  in  the 
Gault  and  Upper  Greensand.  The  precise 
relations  of  these  to  modern  families  are 
doubtful.  The  Recent  Calappa  and 
Matuta  Fabr.,  however,  are  known  from  yw.  i486. 

Eocene  and  later  deposits.  Palaeocorystes  stokesi 

The    remarkable    family    Raninidae,   Jf^eeisand ;  ^Cam^ 
distinguished  by  the  unusual  form  of  the   bridge,  England, 
chelae    and    by    the    elongate    carapace, 

which  is  broader  in  front  than  behind,  is  known  as  early  as  the  Cenomanian  chalk, 
and  its  representatives  are  not  rare  in  the  Tertiary.  Raniella  and  Raninoides 
Milne  Edwards,  are  Cretaceous  genera.  Of  the  few  Recent  genera,  Ranina  Lamarck 
(Fig.  1488)  is  known  from  the  Eocene. 

The  tribe  Brachygnatha,  in  which  the  mouth-frame  is  quadrate,  includes  the  great 
majority  of  the  Brachyura.  It  is  divided  into  two  subtribes,  the  Oxyrhyncha  and. 
Brachyrhyncha. 


Fio.  1487. 

Necrocarcinus'  tricarinatus 
Bell.  Greensand  ;  Cam- 
bridge, England  (after  Bell). 


766 


ARTHROPODA 


PHYLUM  VII 


The  Oxyrhyncka  have  the  carapace  narrowed  in  front  and  produced  into  a  more 
distinct     rostrum.      Fossil    forms    are    few  and    generally    rather    small. 


A,  B,  Ilanina  marestiana  König  (=ß.  helli  Schafli.).     Bocene  ;  Kressenbeig,  Bavaria.     Ventral  and 
dorsal  views.     C,  Chela  of  R.  bouükana  M.  Edw.     Eocene  ;  Biarritz,  France.     1/2- 


Micromaia    Bittner 


Fig.  1489. 

Micromaia  tuherculata 
Bittner.  Eocene  ;  San 
Giovanni  lUarione,  Italy. 
(After  Bittner.) 


lateral.      Since,  however,  it 
they  are  not  separated  in 
the  more  recent  Systems  of 
Classification. 

The  Catometopous 
families  -are  not  well  repre- 
sented  among  fossils.  Litho- 
phylax  Milne  Edwards, 
from  the  Upper  Cretaceous, 
is  an  early  and  somewhat 
doubtful  form.  Galenopsis 
and  Coeloma  Milne  Edwards 
(Fig.  1490) ;  Litoricola 
Woodward ;  and  Palaeo- 
grapsus  Bittner,  are  known 
from  the  Eocene  and  Oligo- 
ce^e.     The    Recent    Gecar- 


and  Microthorax  Noetling,  are  Eocene  and 
Miocene  forms  respectively. 
The  Recent  Lamhrus  Leach 
is  known  from  the  Eocene, 
and  Maia  Lamarck  from 
the  Pliocene. 

The  subtribe  Brachy- 
rhyncha  includes  a  large 
number  of  families  which 
are  often  divided  into  two 
gronps  :  ( 1 )  the  Cyclome- 
topa,  with  the  carapace 
broad  and  arcuate  in 
front ;  and  (2)  the  Gatome- 
topa,  in  which  the  carapace 
is  more  or  less  quadri- 
impossible    to  distinguish   the   two  groups  sharply. 


Fig.  1490. 

Coeloma  vigil  M.  Edw.     Eocene 
Laverda,  Italy. 


Lobocarcinus  pauUno  vjuertemhergicus  v.  Meyer.     Eocene  ' 
Mokkatam,  near  Cairo,  Egypt.     Male. 


SUBCLASS  IT 


EUCRUSTACEA— EUCARIDA 


■67 


cinus   Leach,  is  stated   to  occur  in  the  fresh -water    Miocene  deposits    of  Oeningen. 
Archaeoplax  Stimpson  is  found  in  the  Miocene  of  Gay  Head,  Massachusetts. 

The  Cyclometopoiis  faniilies  have  niany  representatives  in  the  Tertiary  and  a  few 
in  the  Cretaceous.     The  earliest  are  of  Ccnomanian  age,  inchiding  Etyus  Mantell  and, 


Xanthopsiti  kre.->'sniberg(msis  v.  Meyer. 


Fio.  1492. 
Eoceiie  ;  Kressenberg,  Bavaria.     Male, 


?ntral  aiul  dorsal  aspects,  1/2. 


doubtfully,  the  Recent  Xantho  Leach.  Titanocarcinus  and  Palaeocarpüius  Milne 
Edwards,  appear  in  the  Upper  Cretaceous.  The  Recent  Panopeus  Milne  Edwards,  is 
Said  to  date  back  to  the  Cretaceous.  In  the  Eocene  are  found  Harpactocarcinus  Milne 
Edwards  ;  Lohocarcinus  Reuss  (Fig.  1491)  ;  Xanthopsis  M'Coy  (Figs.  1492,  1493)  ;  and 
Neptocarcinus  and  Carcinocarcinus  Lorenthey.  The  Recent  genera  Cancer  Linn. ; 
Ätergatis  de  Haan  ;  and  Etisus  Milne  Edwards,  are  recorded  from  the  Upper  Eocene, 


Ficj.  1493. 

Xonthopsiiihruckraanniv.  Meyer.     Eocene;  Sonthofen, 
Bavaria.     Ventral  view  of  female,  Vi- 


Fig.  1494. 

l'mmmoair cinus  hericarti  (Desni.).  Middle  Meeressanci 
(Miocene) ;  Le  Giie-ä-Tresraes,  France  (after»  A.  Milne 
Edwards). 


although  the  demonstration  of  their  precise  identity  with  Recent  forms  is  not  in  all 
cases  satisfactory. 

The  easily  recognised  Swimming-crabs  of  the  family  Portunidae  are  certainly 
represented  as  early  as  the  Eocene  by  such  forius  as  Psammocarcinus  Milne  Edwards 
(Fig.  1494);  Portunites  Bell ;  and  the  B.ecent  Neptunus  de  Haan.  The  River-crabs 
{Potamonidae)  are  said  to  be  represented  in  the  fresh-water  Miocene  of  Oeningen  by 
the  Recent  genus  Potamon  Savigny  {Thelphusa  Latreille). 


768 


ARTHROPODA 


PHYLUM  VII 


Division  D.     HOPLOCARIDA  Calman. 
Order  1.     STOMATOPODA  Latreille.i 

Carapace  small,  leaving  at  hast  four  of  the  thoracic  somües  dM  and  mv 
covered  with  a  movable  rostral  plate  anteriorly.  Eyes  pedunculate  Eyes  ard 
Znnules  hörne  on  raovahle  segments  of  the  head.  First  fivepans  of  thoracu  hmls 
^b.chelaie,  the  second  pair  very  large.  Abdomen  largeand  depressed,  endmg  ^n  a 
taü-fan.     First  five  pairs  of  abdominal  appendages  carrymg  tufted  güls. 

The  existing  Stomatopods  form  a  very  homogeneous  group,  within  which 
onlv  one  family  (Squillidae)  can  be  recognised,  while  many  of  the  genera  are 
separated  by  comparatively  slight  differences.  Representative  forms  are 
Squüla  Y^hr  ■  LysiosquiUa  ^nd  PseudüsquillaB^nii ;  Gonodactylus  L^treiWe  ; ^nd 
Coronida  Brooks.     Modern  Stomatopods  are  exclusively  marine,  the  adults 

generally  inhabitmg  burrows 
in  the  sand  or  mud  of  the  sea- 
bottom  in  shallow  water,  chiefly 
in  the  tropics,  but  extend- 
ing  also  50  degrees  on  either 
side  of  the  equator.  Many 
species  seem  never  to  wander 
far  from  their  burrows,  into 
which  they  retreat  with  great 
rapidity  when  alarmed.  The 
larval  stages,  on  the  other 
band,  are  exclusively  pelagic, 
of  glass-like  transparen cy,  and 
occur  in  great  numbers  in  the 
plankton  of  the  warmer  seas. 
All  the  Stomatopods  appear 
to  be  of  active,  predatory 
habits.  They  ränge  in  size 
approximately  from  38  to 
340  mm. 

The  existence  of  Stoma- 
topods in  Paleozoic  times  is 
still  doubtful.  Necroscilla 
Woodward,  from  the  English  Goal  Measures,  is  based  on  a  fragment  of  the 
abdomen  and  telson.  Perimecturus  Peach,  from  the  Carboniferous  of 
Scotland,  shows  several  features,  such  as  the  massiveness  of  the  abdomen  and 
the  movable  rostral  plate,  that  suggest  an  affinity  with  this  Order.  In  the 
Kimmeridgian  of  Solenhofen  undoubted  Stomatopods  occur,  some  of  which 
are    even    referred    to    the    Recent    genus    Squilla   Fabr.   (also    known   from 

^  Literatiire:  Münster,  G.  Graf  zu,  Beitrage  zur  Petrefaktenkunde.  Parts  iii.  and  v.,  1840- 
1842. — Mark,  W.  von  der,  and  Schlüter,  0.,  Neiie  Fische  und  Krebse  aus  der  Kreide  von  Westplialen. 
Palaeontogr.,  1868,  vol.  xv.—Kunth,  A.,  Über  wenig  bekannte  Crustaceen  von  Solenhofen. 
Zeitschr.  Deutsch.  Geol,  Ges.,  1870,  vol.  :kx\\.— Woodward,  II.,  Contribntions  to  the  knowledge  of 
fossil  Crustacea.  Quart.  Journ.  Geol.  Soc,  1879,  vol.  xxxv.— Brooks,  W.  A",  Report  on  the 
Stomatopoda.  Scient.  Results  Challenger  Exped.,  Zool.,  1886,  vol.  xyl—Miers,  E.  J.  On  the 
Squillidae.     Ann.  Mag.  Nat.  Hist.,  1880,  ser.  5,  vol.  v. 


Fig.  1495. 

ScuMa  pennata  Münst.  Upper  Jura ;  Bavaria.  A,  B,  Dorsal 
views,  i/i  and  3/j.  c,  Ventral  aspect,  3/^.  a,  e,  First  and  second 
pairs  of  antennae  (aft«r  Kunth). 


I 


CLASS  II  ARACHNIDA  769 

Cretaceous  and  Tertiary  deposits).  Sculda  Münster  {Eeckur  Münst. ;  Buria 
Giebel)  (Fig.  1495),  also  from  the  Solenhofen  beds,  differs  considerably  from 
Recent  forms.  It  is  of  infcerest  to  note  that  larvae  of  Stomatopods  belonging 
to  what  is  known  as  the  JErichthus  type  have  been  recognised  in  the  Cretaceous 
of  the  Lebanon. 

[With  the  undernoted  exceptions  this  revision  of  the  Eucrustacea  has  been  prepared  for  the 
present  treatise  by  Dr.  W.  T.  Calman,  of  the  British  Museum  of  Natural  History.  The 
systeniatic  accouiit  of  tlie  Branchiopoda  and  Ostracoda  has  been  revised  by  Dr.  R.  S.  Bassler, 
of  the  United  States  National  Museum,  and  that  of  the  Phyllocarida  by  Dr.  John  M.  Clarke, 
State  Geologist  and  Director  of  the  New  York  State  Museum  at  Albany. — Editoe.] 


Olass  2.    ARACHNIDA. 

Arthropods  in  which  the  branchial  folds  function  as  gills  or  as  lungs,  or  hecome 
metamorphosed  into  air-tubes  (tracheae).  penetrating  the  hody.  The  hody  is  divided 
into  two  regions,  cephalothorax  and  abdomen,  the  line  between  the  two  passing  behind 
the  sixth  pair  of  appendages.  Cephalothoracic  segments  usually  coalesced,  those  of 
the  abdomen  either  free  or  fused.  Frequently  a  post-anal  spine  is  present.  Antennae 
lacking  ;  genital  openings  upon  the  first  abdominal  somite  ;  midgut  long  ;  spermatozoa 
motile  ;  development  without  nauplius  or  zoea 


The  affinities  of  the  Recent  Limulus  and  its  extinct  Xiphosurous  allies 
with  the  group  represented  by  Scorpions,  Spiders,  etc.,  was  pointed  out  by 
Straus-Dürckheim  as  long  ago  as  1829,  and  additional  reasons  for  removing 
the  Merostomes  from  association  with  Crustacea  were  brought  forward  at  a 
later  period  by  various  writers,  among  whom  may  be  mentioned  Henri  and 
Alphonse  Milne- Edwards,  Dohrn,  Lankester,  van  Beneden,  Kingsley,  Laurie, 
Clarke  and  Ruedemann.  Kingsley,  in  discussing  the  relations  between 
Limulus  and  the  Crustacea  on  the  one  band,  and  the  Arachnida  on  the  other, 
has  indicated  the  following  points  of  agreement :  (1)  a  branchial  respiration ; 
(2)  absence  of  malpighian  tubes ;  (3)  absence  of  salivary  glands ;  (4)  absence 
of  embryonic  envelopes ;  and  (5)  presence  of  Compound  eyes.  He  has  also 
shown  28  points  in  which  Limulus  and  the  Arachnids  agree,  and  in  which 
both  difFer  from  the  other  "  Tracheates  "  (Myriapoda  and  Insecta). 

The  following  points  of  likeness  are  considered  as  of  special  importance 
for  justifying  the  association  of  Merostomata  with  the  Arachnida : 

(1)  The  numerical  homologies  of  segments  and  appendages;  (2)  the  exact 
homologies  existing  in  the  respiratory  organs  ;  (3)  the  fact  that  the  cephalo- 
thoracic appendages  are  pediform,  the  basal  joints  serving  as  jaws ;  (4)  the 
presence  of  true  nephridia  opening  in  the  base  of  the  third  or  fifth  pair  of 
appendages  or  in  both ;  (5)  genital  openings  in  the  seventh  (or  more  probably 
eighth)  Segment  of  the  body ;  (6)  extreme  length  of  the  midgut;  (7)  presence 
of  an  internal  structure,  the  entosternite ;  (8)  inclusion  of  the  ventral  nerve 
cord  and  its  nerves  in  the  external  artery  and  its  branches ;  (9)  the  close 
similarities  in  the  central  nervous  System. 

The  Arachnida  form  a  more  diverse  class  than  the  Insecta,  and  display 
nearly  as  much  differentiation  among  themselves  in  structure,  size  and  habit 
as  do  the  Crustacea.  The  larger  and  more  complex  forms  have  a  fixed  and 
constant  number  of  segments,  and  in  all  Arachnida,  as  in  Insecta  and  the 
higher  Crustacea,  it  is  possible  to  analyse  the  body  into  twenty-one 
VOL.  I  '  3  D 


770 


ARTHROPODA 


THYLUM  VII 


•fo«^      Some  of  these,  however,  may  be  suppressed  during 
:rorgi;;nTÄ  är  Absang  t«  *«  adult  «tage,  0.  el.e  be_g 

fused  in  v.irious  ways.  r,   •/!„  ^„a  crrmmpd  to^ether  in  hi2;her  aggregates 

The  body  Segments  o^^Anjchmd   ar   g^rou^^^^^^^^^^^^^  g^^^^  ^  ^^ 


hanJ 


L.ätera1  eyes 
,■  'Median  e/es 


esosoma 


S  fern  am 

qenital 

•^  operculut 


T 


•I 


■A/ers 


Fig.  1496. 

Duthus  uccitanus  Amoreux,  a  typical  Old-World  Scorpion,     A,  Dorsal,  and  B,  ventral  view. 

1/3  (after  Kraepelin). 

metasoma  (another  name  for  the  "  postabdomen  "  or  "  tail  "  of  earlier  writers, 
Fig.  1496).  The  first  of  these  regions  includes  all  of  the  segments  in  front 
of  the  genital  pore,  usually  six  in  number.  The  second,  or  mesosoma,  begms 
with  the  somite  bearing  the  genital  pore,  and  ends  with  the  last  somite  which 
bears  free  appendages,  typically  six  segments  in  all.  The  third  region,  or 
metasoma,  consists  usually  of  six  segments,  none  of  which  bear  appendages, 
excepting  that  the  terminal  one  often  has  attached  to  it  a  postanal  "  telson, 
which  may  be  considered  as  in  the  nature  of  an  appendage.  The  latter  takes 
in  Scorpions  the  form  of  the  sting,  in  Xiphosures  and  Eurypterids  that  of  the 
spine.  Among  Merostomes,  where  the  body  is  sometimes  sharply  divided 
functionally  into    two    regions    only  ("  cephalothorax "  and    "abdomen"   as 


CLAss  ir  ARACHNIDA  771 

they  are  then  commonly  called),  the  metasoma  together  with  the  mesosoma 
make  up  the  abdomeii.  The  abdominal  segments,  although  usually  distinct, 
are  sometiraes  coalesced  or  fused. 

Arachnids  have  the  sexes  distinct,  and  do  not  reproduce  asexually  or, 
so  far  as  known,  parthenogenetically.  As  a  rule  there  is  little  external 
difFerence  between  male  and  female,  except  for  a  very  frequent  disparity 
in  size  and  an  occasional  modification  of  some  of  the  appendages.  In  several 
genera  of  Eurypterids  two  forms  of  opercular  appendages  of  sexual  significance 
have  been  recognised,  and,  by  analogy  with  Limidus,  the  more  primitive  of 
these  is  assigned  to  the  male,  the  more  elaborate  to  the  female.  From  this 
it  appears  that,  in  Eurypterus  at  least,  the  adult  males  are  smaller  than  the 
females,  as  is  true  of  Limulus  also.  Mites,  Scorpions  and  Pedipalps  are 
viviparous,  but  all  other  members  of  the  class  lay  eggs. 

Primitive  Arachnids  appear  to  have  been  altogether  marine,  and  to  have 
breathed  by  gill-books  borne  on  appendages.  During  or  after  Silurian  times, 
when  their  descendants  acquired  a  terrestrial  habitat  and  changed  from 
water-breathing  to  air-breathing,  the  gill-books  sank  into  the  body  and 
became  lung-books  or  were  replaced  by  tracheae.  Reference  may  be  had  to 
the  recently  published  works  by  Gaskell  on  The  Origiii  of  the  Vertebrates  (1908), 
and  Patten  on  The  Evolution  of  the  Vertebrates  and  their  Kin  (1912),  for  an 
extended  discussion  of  the  so-called  Arachnid  theory  of  the  origin  of 
vertebrates. 

The  Arachnida  are  divided  into  two  subclasses,  Merostomata  and  Embolo- 
branchiata.  The  chief  distinguishing  character  of  the  former  of  these  groups 
is  that  the  gills  are  patent  and  exposed,  and  (in  living  representatives) 
malpighian  tubules  are  absent.  It  is  to  be  noted  that  both  these  features 
are  associated  with  aquatic  life. 

Subclass  A.      MEROSTOMATA  Dana  (emend.  Woodward).i 

(Syn.  Gigantostraca  Haeckel ;  Delobranchiata  Lankester.) 

Six  pairs  of  ambulatory  limbs  about  the  mouth,  the  foremost  of  which  terminales 
in  chelicerae.  The  rest  serve  as  organs  of  locomotion,  and  their  coxal  joints  for 
prehension  and  maslication.  Behind  the  mouth  is  a  single  or  paired  metastoma. 
Prosoma  (^'  cephalothorax")  depressed,  with  usually  a  pair  each  of  median  ocelli  and 
laterally  placed  kidney-shaped  Compound  eyes.  Respiration  by  means  of  lamellar 
branchiae  borne  on  the  appendages  of  all,  or  all  but  one  of  the  first  six  post-cephalic 
Segments,  which  collectively  form  the  mesosoma.  In  Limulus  there  are  no  salivary 
glands,  no  malpighian  tubules,  and  no  embryonic  membranes  (^'  amnion'')  are  found 
in 


Concerning  the  origin  of  the  subclass,  it  is  to  be  noted  that  the  early 
appearance  and  later  atrophy  of  the  abdominal  appendages  is  clearly  a 
feature  that  points  to  a  common  ancestor  for  the  Scorpion  and  Merostomes 

^  The  best  bibliographies  of  Merostomata,  including  also  historical  reviews  of  the  group,  are  to 
be  found  in  the  following  menioirs  : — Woodward,  IL,  A  Monograph  of  the  British  Fossil  Crustacea 
of  the  Order  Merostomata.  Palaeont.  Soc,  1866-78,  pp.  2l-Z().—Pachird,  A.  S.,  On  the  Car- 
boniferous  Xiphosurous  Fauna  of  North  America.  Mem.  Nat.  Aead.  Sei.,  1885,  vol.  iii.  pp.  153-6. 
— Clarke,  J.  M.,  and  Ruedemann,  It,,  The  Eurypterida  of  New  York.  Mem.  14,  N.Y.  State 
Museum,  1912,  p.  438. 


772 


ARTHROPODA  phylum  vii 


having  such  appendages.  Also  it  is  to  be  inferred  that  the  cephalothorax 
in  the  embryo  of  the  Scorpion  retains  ancestral  features,  from  the  facts  that 
its  length  corresponds  to  about  six  abdominal  segments  and  it  equals  the 
latter  in  width. 

A  comparison  of  the  larvae  of  all  three,  Eurypterids,  Limulus  and  the 
Scorpion,  shovvs  that  the  two  last-named  have  lost  the  primitive  form  of  the 
abdomen  by  acceleration ;  that  of  Limulus  being  much  broadened,  that  of 
the  Scorpion  abruptly  contracted  to  the  tail  or  postabdomen,  while  the 
Eurypterids  have  best  preserved  the  original  gradual  and  uniform  contraction. 
The  carapaces  of  Eurypterids  and  the  Scorpion  have  most  nearly  retained 
the  original  proportions  and  form  of  the  common  ancestor.  Of  the  cephalo- 
thoracic  appendages  the  chelicerae  are  alike  in  all  three  groups  and  obviously 
ancestral  in  their  form ;  the  remaining  legs  have  taken  quite  dilFerent  courses 
of  adaptation,  the  Scorpions  having  developed  the  powerful  chelate  pedipalps, 
the  Eurypterids  the  swimming  legs,  while  those  of  Limulus  have  remained 
relatively  undifferentiated. 

These  and  other  facts  tend  to  support  the  inference  that  neither  Limulus 
nor  the  Scorpions  are  derivable  from  Eurypterids,  but  that  all  three,  while 
related,  have  early  separated ;  and  that  the  Eurypterids  are  still  nearest  in 
their  general  aspect  to  the  early  common  ancestor.  The  appearance  of 
Eurypterids  in  the  Cambrian  with  the  essential  characters  of  the  group  is 
in  accordance  with  their  larval  aspect,  while  the  early  Separation  of  Scorpions 
from  the  primitive  stock  is  evinced  by  the  occurrence  of  typical  Scorpions  in 
the  Silurian,  and  by  the  fact  that  in  the  Carboniferous  they  show  a  greater 
diversity  of  form  than  they  do  to-day.  On  the  other  band  the  similarity  of 
the  ancient  Palaeophonus  nuntius  to  Recent  forms  is  conclusive  evidence  that 
the  Scorpions  have  been  very  "persistent  types "  and  had  developed  their 
typical  characters  much  earlier  than  the  Silurian.  There  is  no  reason  to 
doubt  that,  as  there  are  Eurypterids  in  the  Cambrian,  the  Scorpions  also 
reach  back  to  that  era,  and  the  diversion  from  the  common  ancestor  ro.ust 
have  already  been  inaugurated  in  early  Cambrian  time. 

^  As^  to  what  this  common  ancestor  was  we  have  no  clue.  Surely  the 
Trilobites,  which  are  true  primitive  Crustacea,  are  not  ancestrally  or  other- 
wise  closely  related  to  Merostomes,  and  the  latter  even  in  the  Cambrian  are 
far  removed  from  any  possible  synthetic  ancestors,  as  is  shown  by  their  very 
definite  number  of  segments  and  the  arrangement  of  their  appendages.  We 
must  search,  therefore,  for  still  more  primitive  Arthropods  than  the  Crustacea 
as  ancestors  of  Merostomes  and  Arachnids  generally.  In  support  of  this  view 
Clarke  and  Ruedemann  point  to  the  absence  of  anything  in  the  ontogeny  of 
the  Eurypterids  that  would  suggest  a  crustacean  nauplius  stage,  the  admitted 
absence  of  all  crustacean  characters  in  the  adult  forms,  and  the  equal  absence 
of  all  crustacean  features  in  the  ontogenies  of  Limulus  and  the  Scorpion. 

Order  1.     XIPHOSURA  Gronovius.i 

Body  inmature  types,  disti^dly  trilohed  longitudinally.  Cephalothorax  large, 
sermarcular,  the  Compound  eyes,  when  present,  laterally  situated,  and  ocelli  near  the 

l^y\^T8B8-MZTe;^  ''-J'^VZ'  ^''l''f^''  «^^  ^'^stoire  naturelle  et  l'anatomie  des  Limnles. 


CLASS  II  ARACHNIDA— XIPHOSURA  773 

centre  in  front.  First  pair  of  appendages  chelicerate.  Metastoma  with  two  small 
accessori/  plates.  Abdomen  with  seven  to  ten  segments,  which  are  dorsally  free  er 
coalesced  ;  the  six  anterior  ones  provided  with  lamellar  appendages  on  the  under  side. 
Telson  long,  ensiform,  movahle. 

Family  1.     Cyclidae  Packard. 

Cephalothorax   small,    orhicular,    discoidal   or   convex,    calcareous   or   chitinous, 
hounded  hy  a  distinct  border.     Cephalic  appendages  nearly  as  in  embryonic  Limulus. 

Cyclus  de  Kon.  (Fig.  1497).  Known  almost  solely  by  the  orbicular 
cephalothorax  with  its  imperfectly  preserved  appendages,  which  seem  to  be 
simple  swimming  legs.  Their  enlarged  joints  cover  the 
ventral  surface  of  the  carapace  everywhere  except  in  J^^^^^^W^ 

the  centre,  which  is  occupied  by  a  V-shaped  plate, 
towards  the  pointed  extremity  of  which  all  the  basal 
joints  of  the  limbs  converge.  Goal  Measures ;  Great 
Britain,  Illinois  and  Missouri. 


Family  2.     Belinuridae  Packard 


Fig.  \m 


Cyclus      americanus      Pack. 
Goal  Measures  ;  Mazon  Creek, 


Body  limuloid  in  general  aspect.  Cephalothorax 
rounded,  with  long,  slender  genal  spines ;  its  a'ppendages  as 
in  Idrval  Limulus.      Abdomen  with  the  segments  in  part  piinois.   cephalothorax  show- 

,^  -^  ingtracesoflegsandahmentary 

or  almost  wholly  Consolidated  ;  telson  of  variable  length.  canai.   Vi. 

Belinurus  König  (Fig.  1498).  Gephalothorax  hippocrepiform,  its  central 
portion  surrounded  by  a  broad,  flat  marginal  area,  which  at  the  genal  angles 
is  produced  into  a  long,  slender  spine.  Abdomen  with  eight  segments, 
besides  the  much-elongated,  slender  telson ;  seventh  and  eighth  segments  are 
Consolidated.  Upper  Old  Red  Sandstone  and  Goal  Measures  of  Great  Britain 
and  northern  France  (B.  bellulus  König;  B.  reginae  Baily).  Also  in  Goal 
Measures  of  Illinois  {B.  lacoei  Packard). 

—Baily,  W.  II.,  Explanation  of  Sheet  137  of  the  Maps  of  the  Geol.  Surv.  Scotland,  1859.— 
Eemarks  ou  Belinurus.  Ann.  Mag.  Nat.  Hist,  1863,  ser.  3,  vol.  xl— Giebel,  O.  G.,  Limulus 
Decheni.  Zeitschr.  gesammt.  Naturw.,  1863,  vol.  xxi, — Meek,  F.  B.,  and  Worthen,  A.  H.,  Rept. 
Geol.  Surv.  111.,  1868,  vol.  iii.  —  Woodward,  H.,  Notes  on  Neolinmlus,  Cyclus,  Merostomata,  etc. 
Geol.  Mag.,  1869-94,  dec.  1,  vol.  v.  ;  dec.  3,  vols.  vii,,  ix.  ;  dec.  4,  vol.  i. — Dohrn,  A.,  Embryologie 
und  Morphologie  des  Limulus.  Jeuaische  Zeitschr.,  1871,  vol.  vi. — Packard,  A.  S.,  Development 
of  Limulus.  Mem.  Boston  Soc.  Nat.  Hist.,  1872,  vol.  i. — Idem,  Anatomy,  Histology  and 
Embryology  of  Limulus.  Anniv.  Mem.  Boston  Soc.  Nat.  Hist.,  1880. — Ideyn,  Carboniferous 
Xiphosurous  Fauna  of  North  America.  Mem.  Nat.  Acad.  Sei.,  1885,  vol.  iii.  —  Van  Beneden, 
M.  E.,  Systematic  Position  of  King  Crabs  and  Trilobites.  Ann.  Mag.  Nat.  Hist.,  1872,  ser.  4, 
vol.  ix. — Milne-Edioards,  A.,  Recherches  sur  Tanatomie  des  Limules.  Ann.  Sei.  Nat.,  1873, 
ser.  5,  vol.  xvii. — Lankester,  E.  R.,  Limulus  an  Arachnid.  Quart.  Journ.  Microsc.  Sei.,  1881, 
vol.  xxi. — Peach,  B.  N.,  Further  Researches  among  Crustacea  and  Arachnida.  Trans.  Roy.  Soc. 
Edinb.,  1882,  vol.  xxx. —  Williams,  II.  S.,  New  Limuloid  Crustacean  from  the  Devonian.  Amer. 
Journ.  Sei.,  1885,  ser.  3,  vol.  xxx.— Hall,  J.,  and  Clarke,  J.  M.,  Palaeontology  of  N.Y.,  1888, 
vol.  vii. — Kishenouye,  K.,  Development  of  Limulus.  Journ.  Coli.  Sei.  Tokyo,  1891,  vol.  v. — 
Kinrjdey,  J.  >S.,  Embryology  of  Limulus.  Journ.  Morphol.,  1892-93,  vols.  vii.,  viii. — Fritsch, 
A.,  Fauna  der  Gaskohle.  Prague,  1901,  vol.  \\.— Clarke,  J.  M.,  Pseudoniscus  in  the  Eurypterus 
Beds  of  New  York.  Rept.  N.Y.  State  Palaeont.  for  1900.  (54th  Ann.  Rept.  N.Y.  State  Mus.), 
1902. — Rogers,  A,  F.,  Some  new  American  Species  of  Cyclus  from  the  Cqal  Measures.  Kansas 
Univ.  Sei.  Bull.,  1902,  vol.  i.,  No.  10. — Stromer  von  Reichenbach,  E.,  Über  Molukkenkrebse. 
Zeitschr.  Deutsch.  Geol.  Ges.  Monatsber.,  1907,  vol.  \ix.  —  Gaskell,  W.  II.,  Origin  of  the 
Vertebrates,  London,  1908. — Patten,   W.,  Evolution  of  the  Vertebrates  and  their  Kin,  1912. 


774 


ARTHROPODA 


PHYLÜM  VII 


PrestwicUa  Woodw.  {Euproöps  Meek ;  Jnthracopeltis  Boulay)  (Fig.  1499). 
Differs  from  Belinurus  in  having  seven  coalesced  abdominal  segments,  besides 

a  shortand  obtuse  caudal 
spine.  Outline  of  ab- 
domen  subsemicircular, 
central  axis  of  body 
Segments  narrow.  Goal 
Measures;  England, 
northern  France,  Russia 
and  Illinois.  Type,  F. 
anthrax  (Prestw.). 

Protolimulus  Pack. 
Cephalothorax  relatively 
large,  subsemicircular, 
with  small  appendages ; 
its  genal  angles  less  pro- 
duced  than  in  the  two 
preceding  genera.  Abdomen  with  six  segments  besides  a  large,  thick  caudal 
spine.  Upper  Devonian  (Chemung  Group);  Pennsylvania.  Type,  Prot, 
eriensis  (Williams). 

Prolimulus  Fritsch.  Cephalothorax  ellipsoidal,  broader  than  long,  without 
genal  angles,  and  with  relatfively  long  appendages.  Abdomen  rounded, 
shorter  than  the  cephalothorax,  with  lamellar  appendages.  Telson  slender 
equalling  one-half  the  total  body  length.  Permian ;  Bohemia.  Type,  P. 
woodwardi  Fritsch. 


Fio.  1408. 

Belinurus  reqinae  Baily. 
Goal  Measures  ;  Queen's 
Couiity,  Ireland.  Vi  (aft«r 
Woof]  ward). 


Fia,  1499. 


Goal  Meas- 


Prestwichia  danae  (Meek). 
nres;  MazoiiCreek,Grundy  County,  Illinois. 
2/3  (after  Packard). 


Family  3.     Limulidae  Zittel  (King  or  Horseslioe  Crabs). 
(Syn.  Xiphosuridae  Pocock.) 

Body  lov.ger  than  hroad ;  cephalothorax  arched  dorsally,  the  central  portion 
separated  from  the  sides  hy  longitudinal  grooves ;  marginal  area  large  and  flat. 
Abdomen  composed  of  six  Consolidated  segments  forming  a  simple  sub-triangular 
shield,  and  a  long  slender  telson.  Six  pairs  of  abdominal  limbs,  five  of  them  having 
over  a  hundred  pairs  of  gill-leaves. 

imwZws  Müller,  restricted  by  Fabricius  (Fig.  1500).  Living  species  belong- 
ing  to  this,  the  solitary  genus  of  the  family,  occur  on  the  eastern  shores  of  North 
and  Central  America  and  Asia.  According  to  Pocock's  Classification  {Jnn. 
Mag.  Nat.  Hist.,  1902,  ser.  7,  vol.  ix.),  the  four  Asiatic  species  are  referable 
to  two  genera  distinct  from  Limulus  s.s.  In  all  forms  the  four  cephalothoracic 
feet  are  chelate,  the  sixth  pair  is  furnished  with  a  whorl  of  plates  used  in 
pushing  the  animal  through  the  mud.  Gills  are  borne  upon  the  five  posterior 
pairs  of  abdominal  appendages,  the  anterior  pair  being  without  gills,  but 
havmg  the  genital  opening  upon  the  posterior  face. 

ohJJt^  males  are  smaller  than  the  females,  aud  are  further  distinguished  by  the  hooked,  not 
Ron  n-r!'  ^^^"^'"^^^«^  of  the  second,  or  second  and  third  appendages,  a  cliaracter  which  they 
«n?np  l.^  ^  *•  "^f  "^jty-  The  young  embryo  of  Limulus  is  without  an  elongated  caudal 
eSo^  C",,,lTT'/r'^^  ^y  ?^.^'\^  ^^  '^^  abdominal  appendages.  With  its  mSrked  lateral 
Svp^"  f^  abdonien  and  body  divided  into  median  and  lateral  regions  by  longitudinal 
grooves,  it  presents  considerable  reseinblance  to  a  Trilobite,  and  the  stage  has  in  ttct  been 


ARACHNIDA— XIPHOSURA 


775 


called  the  Trilobite  stage  (Fig.  1500,  B).  After  the  first  moult  the  caudal  spine  begins  to 
elongate,  and  at  this  stage,  while  the  abdomen  retains  its  segmented  larval  character,  a  true 
affinity  with  tlie  Paleozoic  Prestwichia  and  Beiinurus  is  clearly  revealed.  The  prevailing 
modern  view  is  that  in  Lirmihis  we  have  a  meniber  of  the  Arachnida  which  retains  its  water- 
breathing  liabit,  and,  in  the  features  of  the  abdominal  appendages,  some  traces  of  the 
characteristic  structure  of  the  primitive  crustacean  stock  from  which  the  Arachnida  originally 
sprang. 

The  genus  first  makes  its  appearance  in  the  Trias,  one  small  species  being  known  from 
tlie  Buntersandstein  of  the  Vosges,  and  another,   L.  vicensis  Bleicher,  from  the  Keuper  of 


B,  Embryo  ot Limulus, 
in  the  so-ctiUed  "Trilo- 
bite stage."  Lateral 
eyes  faintly  shown. 
(After  Dohrn.) 


C,  Limulus  priscus 
Münst.  Muschelkalk  ; 
Laineck,  near  Bay- 
reuth,    i/i- 


Fui.  1500. 


A,  Liimilus  walchi  Desm.  Lithographie  Stone  ;  Solenhofen,  Bavaria.  Dorsal  and  ventral  aspeets,  the 
latter  showing  several  pairs  of  imperfectly  preserved  ambulatory  limbs.  On  the.carapace,  covering  the  prosoma, 
are  seen  impressions  of  the  lateral  eyes. 

Lorraine.  L.  walchi  in  abundant  in  the  Lithographie  Stone  of  Bavaria  ;  L.  natkorsH  and 
L.  woodivardi  are  Jurassic  species  from  Sweden  and  England  respectively  ;  L.  syriacus 
occurs  in  the  Cretaceous  of  the  Lebanon  ;  and  L.  decheni  occurs  in  the  Oligocene  brown  coal 
of  Teuchern,  near  Merseburg.^ 


Order  2.     SYNXIPHOSURA  Packard. 

Body  elongated  ;  cephalothorax  semicircular  with  more  or  less  distindly  defined 
median  axis,  and  no  facial  sntures.     Compound  eyes  generally  present,  ocelli  not 


^  Böhm,  J.,    Über   Limidus   decheni  Zincken.     Jahrb.  Preuss.    Landesanst.    Bergakad.,  1905, 
xxvi.     Oiie  of  these  specimens  described  by  Böhm  represents  doubtless  the  largest  known 


vol 
Limidus 


Fig.  1501. 


7.g  ARTHROPODA  phylum  vii 

ohserved  except  in  Neolimulus.     Abdomen  trüohed,  its  segments  free,  the  pleura  flat 
and  extended,  and  usualUj  terminating  in  lateral  projeäions  or  spmes. 

With  the  exception  of  the  Caml.rian  Aglaspis  (Fig.  1501),  all  the  genera  belonging  to  this 
Order  are  of  Silurian  age,  and  are  too  imperfectly  known  as  yet  to  permit  a  satisfactory 
grouping  into  farailies,  although  several  such  have  been  proposed  by  Packard.  Zittel  united 
theni,  together  witli  certain  genera  of  Xiphosura,  in  the  family  Henuaspidae,  which  term  is 
retained,  but  employed  in  a  restricted  sense. 

Suborder  A.     AGLASPINA  Walcott. 

Body  elongate,  transversely  trilobed,  more  or  less  sharply  divided  into  two  regions 
only.     Cephalothorax  with  or  without  sessile  eyes ;    on  the  ventral  side  it  has  an 
epistoma  and  five  pairs  of  movahle   appendages.     Abdominal 
Segments   all  free,    varying  from   seven   (Aglaspis)    to   twelve 
{Emeraldella)  in  addition  to  the  caudal  spine. 

Family  1.     Aglaspidae  Clarke. 

Cephalothorax  moderately   large,  trilobed ;    abdominal    Seg- 
ments with  distinct  axis  and  pleurae  ;  telson  long  and  spiniform. 

Aglaspis  Hall  (Fig.    1501).      Cephalothorax  relatively 

large,  its  trilobed  central  portion  short  and  conate,  in  front 

Agias^pu  eatoni  whitf.   of  which  are  two  approximate  Compound  eyes ;  bounded 

Ä^ns^r^^/r '  ^'"^''   ^"  ^^^  ^^^^^  ^y  ^  distinct  border.      Abdominal  segments 

described  as    seven    in    number,  flat    and    blade-like,   not 

grooved  on  the  pleura  ;  telson  a  long  and  somewhat  obtuse  spine.     Cambrian; 

Wisconsin. 

Under  this  family  also  are  included  three  genera  from  the  Burgess  shale 
member  of  the  Stephen  formation  (Middle  Cambrian)  of  British  Columbia, 
described  by  Walcott  under  the  names  of  Molaria,  Habelia  and  Emeraldella. 
They  are  remarkable  for  displaying  well-preserved  abdominal  appendages. 

Suborder  B.     BUNODOMORPHA,  nomen  novum. 

This  group  contains  only  the  family  Hemiaspidae,  as  at  present  constituted. 
It  is  a  somewhat  heterogeneous  assemblage,  but  recognised  as  separated  from 
the  Aglaspidae  by  more  than  family  differences. 

Family  1.     Hemiaspidae  Zittel. 

This  family,  in  its  restricted  sense,  may  be  provisionally  maintained 
pending  further  investigation  of  the  rare  and  in  some  respects  obscure  forms 
embraced  by  it.  The  original  definition  of  this  family  is  no  longer  applicable, 
Its  limits  having  become  narrowed  by  the  removal  of  various  genera  to 
other  groups. 

Neolimulus  Woodw.  Cephalothorax  short  and  broad,  crescentic,  elevated 
mesially,  and  bearing  one  or  two  pairs  of  ocelli.  Compound  eyes  lateral  and 
connected  with  the  genal  angles  by  a  suture.  Abdomen  very  broad  anteriorly, 
not  distinctly  divided  into  two  regions,  all  of  its  segments  free,  trilobed  and 


ARACHNIDA— SYNXIPHOSÜRA 


.p.e. 


at  least  nine  in  number;    the  telson  not  observed  in  any  specimen  thus  far 

discovered.      Axial    portion    of    abdomen    diminishing   rapidly   from    before 

backwards.     This  geniis  has  been  understood 

as  connecting  the  Xiphosura  with  the  Synxi- 

phosura.    Silurian  ;  Scotland.    Ty^Q,  N.falcatus 

Woodw. 

Bunodes  Eichw.  (Exapmurus  Nieszk.)  (Fig. 
1502).  Cephalothorax  semicirciilar,  convex, 
with  radial  furrows  from  the  median  portion. 
Facial  sutures  obscure,  converging  from  the 
posterior  to  the  anterior  margin.  According  to 
Patten's  interpretation,  a  median  ("parietal") 
and  a  pair  of  lateral  eyes  are  present,  but  no 
genal  spines.  Abdomen  divided  into  an  an- 
terior portion  (mesosoma  or  "thorax")  consist- 
ing  of  six  trilobite-like  segments  having  a  broad 
median  axis  and  lamellar  pleura  with  diagonal 
pleural  lines ;  and  a  posterior  portion  (meta- 
soma  or  "  postabdomen ")  of  four  narrow  seg- 
ments, besides  a  long  and  acuminate  telson, 
External  surface  of  carapace  and  somites  pus- 
tulose.     Silurian ;  Oesel. 

Hejniaspis  Woodw.  (Limuloides  Salter)  (Fig. 
1503).     General  form  similar  to  that  of  Bunodes. 

Cephalothorax     one-half 

as   long    as   broad,    with 

several      genal      spines ; 

central  portion  well   de- 

fined.     Postcephalic  Seg- 
ments   nine   in   number, 

besides     the     acuminate 

telson,  more  or  less  dis- 

tinctly  divided  into  two 


Fig.  1502. 


Fig.  1503. 
Hemiaspis  limuloides  Woodw. 


Bunodes   lunula,    var.   schrenki,    Niesz. 
Silurian ;    Rootziküll,    Oesel.       Drawing 
made  from  a  plaster  model,  as  restored  by 
re^ions     (mesosoma     and    hatten,  2/1.     Pros,  Prosoma ;    Ms,   Meso- 
"  \         1       •  1         soma,  füllowing  wh ich  are  the  four  narrow 

metaSOma),  SUbtriangUlar  somites  and  telson  constltuting  the  meta- 
in  mifli'nP  nnrl  witli  n  ^°"^*  '  ^^'  I^'i^eral  eye;  pe,  Parietal  eye. 
in     outline,    ana     Wltn    a   (Supposed  antennae  omitted.) 

broad  median  axis  which 

tapers  gradually  from  before  backwards.  Pleura  flat 
and  Short,  the  lateral  margins  of  the  sixth  divided  into 
two  lobes,  as  if  Compound.  Segments  seven  to  nine 
are    narröwer    and    longer    than    the    preceding,   their 


knd"^"Äo:?te^^^^^  combined    length    equalling    that    of    the    tail-spine. 

Silurian ;  Scotland. 

Bunodella  Matthew.  Prosoma  small,  postcephalic  segments  seven  in  number, 
tapering  posteriorly.  Axial  portion  of  the  body  elevated  ;  telson  not  observed. 
Silurian ;  New  Brunswick. 

Pseiidoniscus  Nieszk.  (Fig.  1504).  Prosoma  relatively  large,  convex, 
hippocrepiform,  probably  eyeless  and  without  facial  sutures ;  genal  angles 
extended  into  short  spines ;  surface  obscurely  marked  with  radial  furrows. 
Postcephalic  portion  ("abdomen")  strongly  trilobed  and  trilobitiform,  with 


778 


ARTHROPODA 


PHYLUM  VII 


aradiiallv  tapering  median  axis.  Segments  nine  in  number,  besides  a  short 
Sd  tekon,  all  with  smooth  surfaces.  The  first  five  Segments  w.  h 
i^"  obliquely  grooved  pleura ;  sixth  and  seventh 

partly  conjoined  on  the  pleura,  and  corre- 
sponding  axial  parts  of  the  segments  narrow ; 
eighth  and  ninth  segments  narrow,  lanceolate, 
and  with  increasing  retral  curvature.  Average 
total  length  of  animal  2-5  cm.  Silurian ; 
Oesel  and  New  York  State  (Salina  Group). 

Order  3.     BURYPTBRIDA  Burmeister.  ^ 

Body  elongated,  luith  a  thin  chitinous  epi- 
dermal campace  ornamented  hy  fine  scale-like 
■markings.  Prosoma  with  two  large,  sometimes 
facetted  lateral  eyes  and  a  pair  of  median  ocelli ; 
on  the  ventral  side  with  six  pairs  of  appendages, 
the  foremost  of  which  is  preoral  and  chelicerate. 
Mouth  hordered  posteriorly  hy  a  metastoma. 
"Abdomen"  consisting  of  thirteen  free  segments, 
of  which  the  anterior  six  helong  to  the  mesosoma 
q.nd  hear  ventrally  five  pairs  of  hroad,  foliaceous 
appendages,  corresponding  or  comparahle  to  the 
operculum  and  hranchial  appendages  of  Limulus. 
The  metasoma  consists  of  six  free,  annular  seg- 
ments without  appendages,  together  with  a  long 
or  spatulate  telson. 

This    Order,  which  is  restricted  wholly  to  the   Paleozoic,  embraces   the  largest 
Arthropods  known,  some  of  them  {Pterygotus,  Stylonurus)  having  attained  a  length 

'  Literature :  Dekay,  J.  £.,  On  a  Fossil  Crustaceous  Animal.  Ann.  N.Y.  Lyc.  Nat.  Hist., 
1825,  vol.  l—M'Coy,  F.,  Some  British  Fossil  Crustacea.  Ann.  Mag.  Nat.  Hist.,  1849,  ser.  2,  vol. 
iv. — Roemer,  F.,  Ueber  ein  Exemplar  von  Eurypterus.  Palaeontogr. ,  1851,  vol.  i. — Huxley,  T.  IL, 
On  Himantopterus.  Quar.  Journ.  Geol.  Soc,  1856,  vol.  xii. — Idem,  and  Scdter,  J.  W.,  On  Ptery- 
gotus. Mem.  Geol.  Surv.  United  Kingd.,  1859,  vol.  I—Page,  D.,  Advanced  ^ext-Book  of  Geology, 
1856  and  1S59. —NieskowsM,  J.,  De  Euryptero  remipede.  Dorpat,  1858. — Hall,  J.,  Palaeon- 
tology  of  New  York,  1859,  vol.  iii. — Salier,  J.  W.,  Some  Fossil  Crustacea,  etc.  Quar.  Journ.  Geol. 
Soc,  1862-63,  vols.  xviii.,  xix.  —  Woodward,  H.,  Numerous  papers  in  Geol.  Mag.,  ser.  1,  dec.  1, 
vols.  i.,  ix.,  and  Quar.  Journ.  Geol.  Soc,  vols.  xxi.,  xxiii.,  xxiv.,  xxvii.,  xxviii.,  etc.,  1864-72. 
— Idem,  Monograph  of  British  Fossil  Crustacea,  Order  Merostoniata.  Palaeontogr.  Soc,  1866-78. 
—Orote,  A.  R.,  and  Pitt,  W.  H.,  New  Crustaceans  from  Water- Lime  Group  (Eusarcus,  Ptery- 
gotus, etc.).  Bull.  Buffalo  Soc  Nat.  Sei.,  1875,  vol.  in.— Pohlman,  J.,  Fossils  of  the  Water-Lime 
Group.  Ibid.,  1881-84,  vols.  iv.,  v. — Peach,  B.  N.,  Further  Researches  among  Crustacea  and 
Arachnida.  Trans.  Roy.  Soc.  "Edinb.,  1882,  vol.  xxx.— Schmidt,  F.,  Miscellanea  Silurica.  Mem. 
Acad.  Imp.  Sei.  St-Petersb.,  1883,  ser.  7,  vol.  xxxi.—IIaü,  J.,  Note  on  Eurypteridae.  2nd  Geol. 
Survey  Penn.,  Rept.  PPP.,  lS8i.— /dem,  and  Clarke,  J.  M.,  Palaeontology  of  New  York  State, 
1888,  vol.  \\\.—Whiteaves,  J.  F.,  Palaeozoic  Fossils  of  Canada,  1884,  vol.  iii. — Fraipont,  J., 
Eurypterides  nouveaux  du  Devonien.  Ann.  Soc.  Belg.  Geol.,  1889,  vol.  xvn.—Claypole,  E.  W., 
On  Eurysoma,  Carcinosoma,  etc.  Amel-.  Geol.,  1890-94,  vols.  vi.,  xiii. — Laurie,  M.,  Eurypterid 
Remains  from  Pentland  Hills.  Trans.  Roy.  Soc.  Edinb.,  1892,  vol.  xxxvii.— Idem,  On  Eurypterida. 
Nat.  Sei.,  1893,  vol.  m.—Idem,  Anatomy  and  Relations  of  the  Eurypteridae.  Ibid.,  1893,  vol. 
xxxvii.,  and  Nat.  Sei.,  1893,  vol.  m.—Holm,  Q.,  Über  Eurypterus  Fischeri.  Bull.  Acad.  Imp. 
Sei.  St-Petersb.,  1896,  ser.  5,  vol.  iv.  ;  also  Memoires,  1898,  ser.  8,  vol.  vüi.,  and  Geol.  För.  i 
Stockholm  För.,  1899,  vol.  xxx.—Semper,  M.,  Gigantostraken  des  böhmischen  Paläozoicum.  Beitr. 
Pal.  u.  Geol.  Osterr.-Ung.,  1898,  vol.  n.—Beecher,  C.  F.,  Restoration  of  Stylonurus.  Amer. 
Journ.  Sei,,  1900,  vol.  x.—Idem,  Eurypterid  Remains  from  Missouri.  Ibid.,  1900,  vol.  xii.,  and 
Geol.  Mag.  1900,  dec.  4,  vol.  yin.—Sarle,  C.  /.,  Eurypterid  Fauna  from  the  Salina  Rept.   N.Y. 


Fio.  1504. 

Pseudoniscus  roosevelti  Clarke.  Complete 
indivldual.  Silurian  (Salina  Group) ;  Monroe 
County,  New  York,     '^/i  (after  Clarke). 


CLASS  II 


ARACHNIDA— EUEYPTERIDA 


779 


of  nearly  tliree  metres.      The  presence  of  gills  lipon  the  brancliial  appendages  shows 

that  tlie  Eurypterids  were  aqiiatic,  and  the  structure  of  their  appendages  indicates 

that  they  were  for  the  most  pait  luud-crawlers,  though  sonie  were  good  swinimers. 

They  are  found  associated 

with  cephalopods  and  tri- 

lobites    in    the   Canibrian 

and  Ordovician  of  North 

America  ;     with     cejjhalo- 

pods  and  marine  arthropods 

(Phyllocarids     and    Ostra- 

cods)  in  the  Silurian  ;  with 

Ostra(3ophores  and  Arthro- 

dires  in  the  Devonian ;  and 

with  land  plants,scorpions, 

insects,    fishes,  and    fresh- 

water   amphibians  in   the 

productive  Goal  Measures. 

It   is  apparent,  therefore, 

that  from  being  originally 

marine  forms,  they  became 

gradually    adapted    to 

brackish,  and  possibly  even 

fresh-water  conditions. 

The  Eurypterids  and 
Xiphosures  present  a  num- 
ber  of  points  of  common 
resemblance.  Both  groups 
have  a  prosoma  composed 
of  at  least  six  fused  Seg- 
ments, and  bearing  two 
pairs  of  eyes,  one  pair 
simple,  the  other  Com- 
pound, on  the  dorsal  sur- 
face  of  the  carapace.  The 
number  and  position  of 
the  appendages  of  the 
prosoma  in  Eurypterids 
are  the  same  as  in  Limulus, 
and  the  chelicerae  are 
similarly     constructed     in 

both  cases.  The  basal  joints  of  all  five  pairs  of  legs  in  Eurypterids  are  toothed  and 
function  in  mastication  ;  similarly  in  Limulus  all  are  spiny  except  the  coxae  of  the 
last  pair  of  legs.  In  both  groups  a  similar  process  called  the  epicoxite  is  borne  upon 
the  coxae.  On  the  raesosoma  the  genital  operculum  and  plate-like  appendages  with 
brancliial  lamellae  are  similar  in  both  groups.  A  striking  difFerence  between  them, 
however,  is  seen  in  the  segments  of  the  mesosoma  and  metasoma,  the  somites  being  all 
free  in  Eurypterids,  but  in  Limulus  fused  together.  The  resemblance  between  Euryp- 
terids and  Scorpions  is  none  the  less  striking,  both  groups  showing  the  same  number 


Earypterus 
County,    N.Y. 
Ruedemann). 


Fig.  1505. 

'emipes   Dekay.      Bertie    Waterlime   (Silurian) ;    Herkimer 
Restoration   of   dorsal    aspect.      1/2  (after   Clarke  and 


State  Palaeont.,  1903. — Schmidt,  F.,  Über  Stylouurus  von  Ösel.  Bull.  Acad.  Imp.  Sei.  St-Petersb., 
1904,  ser.  5,  vol.  xx. — Seemann,  F.,  Zur  Gigantostrakenfauna  Böhmens.  Beitr.  Pal.  u.  Geol. 
Österr.-Ung.,  1906,  vol.  x'w.  —  I'iurost,  1\,  Crustaees  du  nord  de  la  France.  Ann.  See.  Geol. 
Nord,  1911,  vol.  xl. — Clarhr,  J.  i/.,  and  Ruedemann,  R.,  Eurypterida  of  New  York.  Mem. 
N.Y.  State  Mus.  110.  xiv.,  1912. 


PHYLÜM  VII 


•80 


ARTHKOPODA 
three  regions  of  tlie  body,  and  the  appendages  of  the  prosoma 


of  Segments  in  the 

iff  identical  in  nui ^  ., 

Tl  e  gcneral  fonn  of  tl.e  boly  in  Euryptends 

„f  a  Scorpiou,  Imt  ia  relativoly  broader  and  shorter. 


beingidentical  in_numteandl.«<iUon.^^^^^^^^.^^^  ^^.^    ^^^^^  .^  somewliat  like  tliat 


■t# 


-^&^^' 


Tlie  prosoma  or  cephalotliorax 
consists    of    six    fiised    Seg- 
ments covered  by  a  quadrate 
carapace     witli     its     front 
angles  rounded.    This  bears 
on  its  dorsal    surface  two 
pairs  of  eyes— large  kidney- 
^^haped     lateral    eyes,    and 
median   ocelli.      Tlie   Com- 
pound    lateral     eyes     are 
smootb  in  theEnrypteridae, 
facetted  in  thePterygotidae. 
As   sliovvn   by  Clarke  and 
Rnedemann,  tbese  facetted 
eyes  are  identical  in  struc- 
ture  with  tbose  of  Limulus. 
On  tlie  ventral  surface 
of  tlie  prosoma  (Fig.  1506) 
are  seen  six  pairs  of  appen- 
dages, of  wliicb  tbe  first  pair 
(the  chelicerae)  are  preoral 
in  Position,  and  the  remain- 
ing  five  pairs  are  found  at 
the    sides   of   the  elongate 
mouth,  and  are  developed 
as  legs.     These  legs  consist 
typically  of   a  basal  Joint 
{coxa),    the    inner    margin 
of    which     (gnathohase)    is 
provided    with    teeth    and 
able  to  function   in  masti- 
cation,  much  as  in  Limulus 
or  Ä23US,  whilst  the  distal 
part    of    each     appendage 
served  as  an  organ  of  loco- 
motion.      The   ambulatory 
part  of  the  appendages  is 
usually  six-jointed,  and  is 
attached    to    a  small,  oval 
"epicoxite"  at  its  anterior  angle  exactly  in' the  same  fashion  as  in  Limulus.     The 
fifth  pair  of  legs    is  spineless  and  slender,   probably  serving   as  balancing  organs. 
The  sixth  pair  is  characterised  in  all  members  of  the  order  by  its  greater  size  and 
usually  somewhat  flattened  form,  as  well  as  by  its  termination  in  an  oval  plate  or 
claw.     This  last  pair  is  commonly  termed  the  palette  or  paddle,  and  seems  to  have 
had  a  swimming  function,  although    it    is  probable  that  the  animal  used  it  also 
for  anchoring  or  burying  itself  in  the  mud. 

Behind  the  prosoma  are  twelve  free  Segments,  plus  the  tail-spine,  of  which  the 
fii-st  six  form  the  mesosoma,  and  the  remainder  the  metasoma.  On  the  ventral 
surface  the  Segments  of  the  mesosoma  bear  pairs  of  plate-like  appendages,  each  of 
which  slightly  overrides  the  next  succeeding  one.  These  appendages  bear  on  their 
inner  (posterior)  surfaces  the    lamellar  branchiae,  which  are   oval  in  outline   (Fig. 


Fig.  1506. 

Eurypterus  fischeri  Eicliw.      Silurian ;    Island   of   Oesel. 
individual,  1/2  (from  Holm). 


Female 


CLASS  II 


AEACHNIDA— EURYPTERIDA 


781 


1509),  and  in  a  general  way  are  comparable  to  the  leaf-like  external  gills  of  Limulus. 
Tlie  first  and  second  Segments  of  the  mesosoma  are  covered  on  the  ventral  surface 
by  tlie  genital  operculum,  wliich  consists  of  a  pair  of  plates  meeting  in  the  middle 
line  and  liaving  a  median  lobe  attached  to  them.  Tlie  latter,  frora  analogy  with 
Limulus,  is  undoubtedly  genital  in  function,  and  varies  in  form  in  the  same  species, 
correlating  with  sex. 


Family  1.     Eurypteridae  Burmeister. 

Body  elongate,  narrow  in  form  to  hroadly  expanded  in  the  mesosomatic  re 
Prosoma  suhquadrate  to  suhtriangidar  in  outline,  with  rounded  front  angles  ;  telson 
spiniform.  Compound ey es smooth, 
not  facetted,  gener ally  near  the 
middle  of  the  cephalic  shield  ;  no 
epistoma;  chelicerae  not  extending 
heyond  the  frontal  margin  of  the 
carapace.  Sixth  paif  of  legs 
adapted  for  either  smmming  or 
crawling.  Femade  genital  append- 
age  composed  of  several  lohes. 

Certain  genera  which  are  here 
included  in  this  family  {Eusarcus, 
Stylonurus,  etc.)  present  rather 
Wide  departures  from  the  type,  and 
in  the  recent  Classification  proposed 
by  Lankester  (Encyclop.  Brit., 
12th  ed.,  article  on  Arachnida) 
theyare  placedin  sejmrate  families. 
Concerning  geneticrelations,  much 
new  light  has  been  gained  through 
study  of  the  stages  of  development 
of  the  principal  genera,  and  by 
comparison  of  them  with  the 
primitive  and  much  generalised 
Strabops  from  the  Cambrian. 
This  genus  is  one  of  the  earliest 
known  Eurypterids,  and  is  re- 
garded  by  Clarke  and  Ruedemann 

as    an    actual    progenitor    of    most    ^''^^'^(^^opsthacheri  Beecher.    Fotosi  limestone  (Upper  Cambrian) ; 
CM      •  X-  *  -,.  ^^-   Fran(;ois  County,   Mo.      Restoration  of  dorsal  aspect.      2/„ 

bllurian     iorms.         Accordmg     to    (after  Clarke  and  Ruedemann). 

the  authors  just  named  the  Euryp- 
terids studied  by  them  pass  through  a  so-called  Strahops-stage  during  the  course  of 
their  nepionic  development.      It  has  also  been  shown  by  them  that  the  ontogeny  of 
Eurypterids   fully  corresponds   to   that  of  Limulus  in  lacking  any  indication  of  a 
nauplius  or  zoea  stage. 

Strahops  Beecher  (Fig.  1507).  Prosoma  small,  comparatively  wider  than 
in  Eurypterus,  but  the  eyes  further  back,  small,  and  very  far  apart ;  body 
somites  not  distinctly  differentiated  into  two  regions  (mesosoma  and 
metasoma),  twelve  in  number  besides  the  short  and  blunt  tail-spine.  In  view 
of  its  generalised   characters   this   genus   is   eminently  fitted  to   serve   as   a 


Fig.  1507. 


782 


ARTHROPODA 


PHYLUM  VII 


prototype  from  which  later  Eurypterids  are  descended.     Cambrian  (Potosi 
limestone) ;  Missouri. 

Eurypterus  Dekay  (Lepidoderma  Reuss ;  (?)  Campylocephalus  Eichw.)  (Figs. 
1505,  1506,  1508).  Body  elongate,  narrow,  attaining  sometimes  a  length  of 
1  m.  Prosoma  contained  five  or  six  times  in  total  length  of  the  body,  depressed 
convex,  subquadrate,  with  rounded  anterior  angles.  Anterior  margin  nearly 
straight,  posterior  slightly  concave.  Eyes  reniform,  somewhat  in  front  of  the 
middle ;  between  them  and  close  to  the  axial  line  are  two  ocelli.  The  entire 
prosoma  bordered  by  a  narrow  marginal  furrow,  and  the  margin  broadly 
enfolded  on  the  ventral  side.  In  the  middle  of  the  lower  side  is  the  cleft- 
shaped  mouth,  which  is  bordered  laterally  by  the  basal  segments  of  the  fifth 
pair  of  legs,  and  posteriorly  by  the  large  oval  metastoma.  Ordovician 
(Normanskill  shale)  to  Permian ;  Europe  and  North  America. 

The  first  pair  of  appendages  was  regarded  by  Woodward  and  Schmidt  as  filiform  and 
tactile.  Laurie,  Holm,  Clarke  and  Ruedemann,  and  others,  however,  have  shown  that  tliey 
are  chelicerate,  and  thus  in  accord  with  homologous  structures  in  other  niembers  of  the 
faniily.  The  three  succeeding  appendages  are  six-  or  eight-jointed  and  covered  with  fine 
spines.  The  fifth  pair  is  eight-jointed,  and  longer  than  those  in  front  of  it.  The  posterior 
pair  is  a  powerful  swimming-organ  ;  its  great  subquadrate  basal  joints  enclose  the  metastoma, 
and  together  with  this,  cover  nearly  one-half  of  the  ventral  side  of  the  prosoma. 

All  of  the  body  segments  are  free.  The  first  six  form  the  mesosoma,  and  together 
collectively  occupy  about  one-fourth  of  the  body-length.  They  are  short  and  broad,  and 
nearly  uniform  in  shape  ;  but  the  second  segment  has  lost  its  hard  skeleton  on  the  ventral 
surface,  and  the  tirst  Covers  the  greater  part  of  the  genital  operculum.     This  first  segment 

joins  the  posterior  margin  of  the  prosoma 
and  consists  of  two  lateral  portions  and 
a  median  process.  All  six  segments  of 
the  mesosoma  are  moderately  overlap- 
ping  on  the  ventral  side,  and  each  is 
divided  by  a  median  suture  or  cleft  into 
two  parts.  After  these  follow  the  six 
ring-like  segments  of  the  metasoma, 
which  diminish  gradually  in  Avidth  pos- 
teriorly, and  the  body  is  terminated  by 
a  long,  slender  telson.  The  latter  is 
properly  to  be  regarded  as  an  appendage 
of  the  twelfth  segment,  as  indicated  by 
the  Position  of  the  anus  in  relation  to  it. 
Larval  stages  have  the  telson  short, 
thickand  four-sided,  with  dorsal,  ventral 
and  two  lateral  edges,  corresponding  in 
form  to  that  of  the  primitive  Strahops. 

About  twenty-five  species  of  Eury^-)- 
terus  are  known,  the  largest  being  about 
1  m.  long.  They  are  found  for  the  most 
part  in  argillaceous  or  sandy  deposits 
in  transition  strata  between  the  Silurian 
and  Devonian  of  England,  Gotland, 
Oesel,  Podolia,  and  in  the  Water-lime 
Group  (Silurian)  of  New  York.  They 
are  rare  in  the  Devonian,  but  occur 
again  more  frequently  in  the  Goal 
Measures  of  Scotland,  Silesia,  Bohemia, 
Saarbrücken,  and  Pennsylvania.  The 
last  survivor  is  from  the  Permian  of 
«««iation  with  land  plants  ( /Fafc/a«,  Äy««^fe™)    "Typ";  i "«ISe.  tZy  "  "™''  '" 

leg  Sbnedln*;!"'"'  "'  ,?^-'i<'--"-     Terminal  claw  (with  Joint)  of  sixth 


Fio.  1508. 
^yer«.rmipe.  Dekay.     Bertie  Waterlinie  (Silurian); 


TnHinn.,       T  i^      r;-!'--"^^  «p^ie ;  nitn  pair  undiffen 

inaiand.      iype,  Luryptems  kokomoensis  Miller  and  Gurley. 


CLxVSS  II 


ARACHNIDA— EUKYPTERIDA 


783 


Tyloptcriis  Clurke  and  Ruedemann.  Thick  calcareo-chitinous  integument, 
witli  median  divided  knobs  on  tergites.  Silurian  ;  Canada.  Type,  Eurypterus 
hoylei  Whiteaves. 

Echinognathns  Walcott.  Imperfectly  known.  Cephalothoracic  appendages 
with  numerous  curved  spines,  indicating  an  animal  of  large  size.  Ordovician ; 
New  York. 

Megalograptus  Miller.  Richmond  beds  (Lowermost  Silurian)  ;  Ohio. 
Known  only  by  fragmentary  remains. 

Dolichoptenis  Hall.     Sixth  prosomatic  appendage  has  the  terminal  claw 
developed  into  an  elliptical  oar-plate.     Waterlime  (Upper- 
most  Silurian) ;  New  York.     Silurian  ;  Oesel. 

Eusarcus  Grote  and  Pitt  (Eurysoma  and  Carcinosoma 
Claypole).  Eurypterids  with  the  six  mesosomatic  Seg- 
ments greatly  expanded,  the  next  following  of  the 
metasoma  being  abruptly  contracted.  Prosoma  subtri- 
angular,  Compound  eyes  at  apex  in  front ;  metastoma 
subtriangular.  Second  pair  of  legs  the  longest.  Terminal 
Joint  of  the  sixth  prosomatic  appendage  not  expanded. 
General  aspect  of  body  scorpion-like.  Ordovician  and 
Silurian ;  New  York,  Indiana,  and  Pentland  Hills,  Scot- 
land. 

Anthraconedes  Meek  and  Worthen.  Like  Eurypterus^ 
but  with  spines  on  the  falcate  posterior  angles  of  the 
abdominal  segments.  Goal  Measures ;  Illinois  and 
Pennsylvania. 

Adelophthalmus  Jordan  and  von  Meyer.  Comprises 
eyeless  Eurypterids.     Goal  Measures ;  Saarbrücken. 

?  Eurypterella  Matthew.  Probably  not  a  Eurypterid. 
Devonian ;  New  Brunswick. 

?  Beitina  Walcott.  Probably  not  a  Eurypterid. 
Algonkian ;  Montana. 

Slimonia  Page  (Himantopterus  Salter)  (Fig.  1509). 
Body  attaining  a  length  of  60  cm.,  and  width  of  15  cm. 
Prosoma  subquadrate,  with  anterior  marginal  eyes  and 
median  ocelli.  Preoral  appendages  in  the  form  of  small  shlrr"scoSid"'Rts"toia- 
stout  pincers,  much  like  chelicerae  in  Limulus.  Of  the  tion '  of  ventral  aspect, 
five  pairs  of  postoral  appendages,  the  first  is  modified  to  Le^msoma^i?— vl^ViS- 

tal  operculum  VII.— VIII., 

Segments  of  the  mesosonia 

The  first  two  sternites  vii- -  xii        metasoma 

.  .  XIII.— XVIII.,  and  telson 

are    represented    by  the   genital  plate  and  its  posterior  xix.    Dotted  areas  of  the 

j.    .    •  i.t,         J.I,        ü  j'  ^'  1    j.        1  •  mesosoma     are     branchial 

divisions ;   the  other  nve  are  discontinuous  plates  bearing  lameiiae  .showhig  tiirough 
branchial    lameiiae    on    their    inner    surface.      The    five  f)^%£'Srier'"'^^^^°'' 
posterior    segments    are    long,    narrow,    and    cylindrical. 
Telson  like  that  of  Pterygotus,  but  produced  into  a  longer  spine.     Only  one 
species  known.      Old  Red  Sandstone  ;  Scotland. 

Stylonurus  Pa,ge  (Fig.  1510).  Body  similar  in  general  proportions  to 
Pterygotus,  and  often  exceeding  1  m.  in  length.  Prosoma  quadrate  or  sub- 
pentagonal,  its  margins  bent  under.  Eyes  large,  approximate,  sometimes 
supported  by  strong  orbital  ridges ;  ocelli  on  the  slope  of  a  median  ridge. 
Preoral    appendages    chelicerate.       The    five    pairs    of    postoral   appendages 


Fig.  1509. 
Slimonia     acuminata 


form  tactile  organs.      The  first  seven   postcephalic  seg-  äinnent8"of"the^ 
ments  much  wider  than  the  rest. 


784 


ARTHKOPODA 


PHYLUM  VII 


increase  in  len-th  from  the  first  backward,  the  last  pair  enormously  elongated, 

heincr  nine-jointed,  extending  almost  to  the  end  of  the  telson,  and  termmating 

^  •'  in  a  Sharp  claw.      The  first  two 

pairs  of  legs  frequently  bear 
paired  leaf-life  spines.  Telson 
long  and  slender.  Silurian  and 
Devonian  ;  Scotland,  Russia,  New 
York,  and  Pennsylvania. 

Subgenus :  Ctenopterus  Clarke 
and  Ruedemann.  First  three 
pairs  of  legs  with  numerous  paired 
spines  to  each  segment. 

Tarsopterus  Clarke  and  Ruede- 
mann.      Silurian  ;  New  York. 

Drepanopterus  Laurie.  Body 
as  in  Stylonurus,  but  the  pos- 
terior legs  much.  less  elongated. 
Silurian  ;  Scotland  and  Indiana. 

Family  2.     Pterygotidae 
Lankester. 

Body   elongate,    narrow.      Pro- 
soma semielliptical  to  subquadrate  in 
outline;  telson  spiniform  in  Hugh- 
spatulate     and     hilohed 
te  in  all  other  genera.     Com- 
eyes    facetted,     marginal ; 
epistoma  present ;    chelicerae    some- 
times  greatly  extended.     Last  pair 
of  legs  always  adapted  to  swimming. 
Female  genital  appendage  simple. 

P ier ygotus  Agassiz  (Figs.  1511-1512).  Eurypterids  sometimes  of  gigantic 
size,  attaining  a  length  of  over  2  m.  Prosoma  semi-ovate,  with  anterior 
marginal  facetted  eyes  and  median  ocelli.  The  metastoma  is  a  heart-shaped 
plate  attached  along  the  middle  line  to  the  ventral  wall  of  the  prosoma, 
between  the  bases  of  the  last  pair  of  legs,  and  extending  outwards  and 
forwards  so  as  to  enclose  the  jaws  in  a  kind  of  Chamber.  Epistoma  a  thin 
plate,  occupying  the  same  position  as  the  hypostoma  in  trilobites,  and  having 
the  preoral  appendages  attached  close  to  its  posterior  border.  The  latter  are 
large  pincers,  probably  prehensile  in  function;  by  Schmidt  and  Woodward 
they  are  represented  as  many-jointed,  but  it  is  now  known  that  they  consist 
of  but  three  long  joints.  Behind  the  mouth  are  four  pairs  of  slender  Walking 
legs,  followed  by  the  large  "  swimming  feet,"  which  are  similar  to  those  in 
Eurypterus,  except  that  they  are  less  broadly  expanded  at  the  tips.  Telson 
an  oval  plate,  terminating  in  a  slight  projection.  The  species  first  referred 
to  this  genus  (P.  proUematicus  Ag.)  is  imperfectly  understood,  and  P.  anglims 
Ag.,  which  is  well  known,  is  generally  accepted  as  the  typical  form  of  the 
genus.  Ordovician ;  New  York.  Silurian ;  Wales,  Scotland,  Sweden,  Oesel, 
Russia,  New  York,  and  Australia.     Old  Red  Sandstone ;  Scotland. 


Fig.  1510. 

Stylonurus  excelsior  Hall.  Chemung-Catskill  Group  (Upper 
Devonian) ;  Pennsylvania.  Restoration  of  dorsal  aspect. 
1/20  (after  Clarke  and  Ruedeniann). 


ARACHNIDA— EURYPTERIDA 


785 


Erettoptems   Huxley   and    Salter.     Like    Pterygotus,   but    with   a    bilobed 
telson.     Siluriari ;  Lanarkshire. 

Hughmilleria  Sarle.     Small  animals  with  carapace  as  in  Pterygotus,  chelate 


Fig.  1511. 

Pterygotus  buffaloensis  (Pohlman).     Bertie  Waterlime  (Silurian) ;  BufFalo,  New  York, 
A,  dorsal,  and  B,  ventral  aspect.     1/30  (after  Clarke  and  Ruedemann). 


Restoration  of 


appendages  on  short  legs,  and  telson  as  in  Eurypterus.     Epistoma  lyre-shaped, 
flanked  by  lateral  shields.     Ordovician  and  Silurian  ;  New  York. 

Glyptoscorpius  Peach.  Body 
attaining  a  length  of  30  cm. 
Surface  covered  with  highly 
developed  scale-markings.  The 
animal  is  provided  with  a  pair 
of  comb-like  structures  supposed 
to  resemble  the  pectines  of 
scorpions,  and  the  legs  end  in  a 
double  claw.  Lower  Carboni- 
ferous ;  Scotland. 

Hastimima  White.     Large  forms  having 
impressed  median  ventral  plate. 
Devonian  of  South  Africa. 


Fig.  1512. 

Pterygotus  buffaloensis  (Pohlman).     Bertie  Waterlime  (Silurian) ; 
Buffalo,  New  York.     The  toothed  anterior  chela.     1/2. 

i  pterygotoid  hastate  telson  with 
Carboniferous ;  Brazil,  Nova  Scotia  (?)  and 


Order  4.     LIMULAVA  Walcott. 

Body  elongated.  Frosoma  with  lateral  or  marginal  eyes ;  on  the  ventral  side 
with  five  pairs  of  appendages,  some  of  which  are  hiramous.  Fostcephalic  portion 
of  hody  {mesosoma  and  metasoma)  consisting  of  twelve  segments,  the  anterior  nine  of 

VOL.  I  3  E 


786  ARTHROPODA  phylüm  vii 

which  bear  gills ;  the  last  has  a  central  spatulate  process  that,  comhined  with 
swimmerets,  forms  a  strong  caudal  fin. 

It  is  doubtful  whether  this  group,  which  in  the  biramous  jointed  legs  and 
Compound  telson  possesses  crustacean  features,  belongs  to  the  merostomes  or 
connects  the  latter  with  the  crustaceans. 

Walcott,  from  his  discovery  of  jointed  body  appendages  in  Sidneyia,  is 
inclined  to  the  view  that  this  genus  is  transitional  between  trilobites  and 
Eurypterids.  One  family  is  recognised,  the  original  diagnosis  of  which  is 
given  as  follows  : 

Family  1.     Sidneyidae  Walcott. 

Cephalothorax  small,  without  lohes,  eyes  marginal;  ventral  side  with  large 
epistoma,  five  pairs  of  movahle  appendages,  the  gnathohases  of  the  three  posterior 
pairs  forming  organs  of  manducation.  Abdomen  twelve-jointed,  the  three  posterior 
Segments  annular  and  narrow,  the  terminal  one  forming,  with  lateral  swimmerets,  a 
fan-like  tail ;  nine  anterior  segments  with  a  pair  of  branchial  appendages  on  each  ; 
the  three  posterior  segments  without  ventral  appendages.  Surface  smooth,  or 
ornamented  by  narrow,  irregulär,  fine  imbricating  ridges. 

In  this  family  are  placed  two  genera,  Sidneyia  and  Amiella  Walcott,  from 
the  Ogygopsis  shale  of  the  Stephen  formation  (Middle  Cambrian),  near  Field, 
in  British  Columbia,  Canada.  They  are  described  and  figured  in  Smithson. 
Mise.  Coli.,  1911-12,  vol.  Ivii.,  nos.  2  and  6.  Sidneyia  inexpectans  Walcott, 
the  type  species,  which  attains  a  length  of  about  17  cm.,  is  represented  by 
very  fine  material.  The  accompanying  genus  Amiella  is  less  satisfactorily 
preserved,  and  there  are  indications  of  its  occurrence  also  in  the  Cambrian  of 
Yunnan,  in  Indo-China. 

[The  foregoing  «chapter  on  the  Merostomata  has  been  revised  for  the  present  edition  by 
Dr.  John  M.  Clarke,  New  York  State  Geologist,  and  drawings  for  several  new  figures  of 
Eurypterids  have  been  kindly  furnished  by  hini  and  Dr.  R,  Ruedemann,  ofAlbany.— Editor.] 

Subclass  B.     EMBOLOBRANCHIATA  Lankester.' 

Arthropods  with  at  hast  three  preoral  segments  in  the  adult  steige,  ivith  one  pair  of 
preoral  appendages  called  chelicerae,  and  five  postoral  pairs,  the  anteriormost  of  ivhich 
are  the  pedipalpi.  Chelicerae  two-  or  three-jointed,  retrovert  or  chelate.  Pedipalpi 
pediform,  chelate  or  retrovert,  typically  six-jointed,  legs  typically  seven-jointed.  Uead 
fused  with  at  hast  one  thoracic  segment,  usually  with  the  entire  thorax,  forming  a 
cephalothorax  or  prosoma.  Genital  opening  on  the  first  somite  of  the  mesosoma. 
Nephridia  modified  as  coxal  glands.     Abdomen  typically  composed  of  twelve  segments, 

^  Literature  :  Gomstock,  J.  H.,  The  Spider  Book.  New  York,  m2.—Fritsch,  A.,  Paläozoische 
Arachuiden.  Prague  1904.-ÄWi,  C.  L.,  and  Berendt,  J.  C,  Die  im  Bernstein  befindlichen 
Crustaceen,  Myriapoden,  Arachniden  und  Apteren  der  Vorwelt.  Berlin,  l^U.—Lankester,  E.  R., 
Ar  icles  on  Arachuida  and  Arthropoda  in  Encycl.  Brit.,  IQll.-Laurie,  M.,  Gn  a  Silnrian  Scorpion 

tl^^ff  ""^^^''^'^'/^f^^^^ozoic  Arachnida  of  North  America.  Trans.  Conn.  Aead.  Sei.  (In 
KTainTn  Q  im'i  ^^"«g^^P^^  of  the  terrestrial  Carboniferous  Arachnida  of  Great  Britain. 
/./ r  3;  r'-'  ^l^h~n''f'''  ^-  ^^•'  ^''''^  «Pi^^^«-  H^r^^rd  Univ.  Bull.,  1882,  vol.  ii.- 
His  '  «QO  V  r-'  r?"  ^f^,°"^f«^of  Arachnida  of  North  America.  Mem.  Boston  Soc.  Nat. 
fr^l  ArSids  'r;;^  tT^  P  V^c.*^'"  ^r^"''  ^^''^^  ^'''^'^'  °f  ^^^  World,  including  Myriapods 
branchLta  in   Pnn  1     1  ^-S-  ^«0  •   Surv.  No.   71,   ISn.- Warhurton,    C,   Chapter  on   Embolo- 

r^i   le  Siluria^    'n^^  A  "'"'"^   ^S^^^F'     ^""^^"^'   ^^OQ.-Whüßek,   k  P.     Fossil    Scorpion 

trom  the  Silunan  rocks  of  America.     Bull.  Amer.  Mus.  Nat.  Hist.,  1885   vol  i 


SÜBCLASS  II 


EMBOLOBRANCHIATA 


787 


even  when  external  segmentation  is  subsequently  lost.      Anus  on  last  abdominal  segment. 
Eyes,  when  present,  simple,  variable  in  number.     Respiration  by  lung-books  or  tracheae. 

Tlie  subclass  of  Embolobraiicliiata  incliides  spiders,  scorj)ions,  niites,  ticks,  etc., 
and  comprises  in  all  thirteen  orders.  Of  these  four  are  eiitirely  extinct,  and  of 
tliose  still  living  six  liave  continued  to  exist  since  tlie  Paleozoic,  and  only  one  is  not 
known  to  have  fossil  representatives.  So  far  as  tlie  evidence  of  extinct  forms  goes, 
tlie  older  menibers  of  tlie  various  Orders  seem  to  have  resembled  to  a  remarkable 
degree  tliose  existing  at  tlie  present  day,  and  serve  to  illiistrate  the  extreme  antiquity 
of  living  types  of  invertebrate  animals.  Tlie  majority  of  fossil  species  is  known  from 
remains  preserved  in  amber  of  Lower  Oligoceiie  age  in  eastern  Prussia.  The  most 
delicate  parts,  including  the  finest  hairs  and  sjDiders'  webs  are  to  be  fonnd  practically 
iinaltered  within  this  transparent  fossil  resinoiis  siibstance  which  exiided  from  ancient 
Cüiiiferous  trees. 

The  Order  Scorpionlda   (Scorpiones)  is   the  oldest  among  the  Embolobranchiata 


Fia.  1513. 


Upper  Silurian  pninitive  Scorpions,  l'alaeopTionus.  A,  P.  nuntiils  Thor,  and  Lindst.  Ludlow  series 
(Clunian);  Gotland.  Hcstoration  of  dorsal  aspect.  ^/s  (after  Pocock).  B,  F.  caleilonicus  Peach.  Ludlow 
series  (Clunian) ;  Lanarkshire.  Reconstruction  of  ventral  aspect,  in  which  the  space  for  a  genital  operculuni, 
the  pair  of  pectens,  and  the  absence  of  any  evidence  of  pulmonary  Stigmata  are  noticeable  features.  »/o  (after 
Pocock). 

and  bears  witness  to  a  common  origin  witli  the  Eurypterida.  Scorpions  are 
characterised  by  having  three-jointed  chelate  chelicerae  and  six-jointed  chelate 
pedipalpi ;  the  head  is  fused  witli  the  thorax  ;  the  abdomen  is  composed  of  twelve 
Segments,  the  last  five  of  which  are  annular  and  form  the  so-called  postabdomen  or 
tail.  At  the  end  of  this  latter  is  a  telson  modified  as  a  poison  gland  witli  sting. 
On  the  ventral  surface  is  foiind  a  characteristic  pair  of  appendages,  the  "comb." 
Lung-books  are  present  in  four  pairs. 

Silurian  Scorpions  ai'e  grouped  together  uiider  the  suborder  Apoxypoda,  which 
contains  a  single  fainily  represented  by  the  genera  Palaeophonus  Thorell  (Fig.  1513) 


788 


ARTHROPODA 


PHYLUM  VII 


and  Proscorpius  Whitfield.  The  former  of  these  comprises  three  species  occiirring  in 
the  Upper  Silurian  (Clunian)  of  Gotland  and  Lanarkshire,  and  tlie  latter  a  Single 
one  froni  the  Bertie  Waterlime  of  New  York.  Pocock  has  suggested  that  the 
supposed  mesosomatic  "  sternites "  of  Palaeophonus  are  really  broadly  laminate 
gill-bearing  appendages,  as  they  have  been  shown  to  be  in  Eiirypterus.  Similar 
appendages  occiir  also  in  Eohuthus,  and  it  is  inferred  that  respiratory  lamellae  lay 
beneatli  tlieni  as  they  do  in  Limulus.  Thus,  the  breathing  organs  in  primitive 
Scorpions  were  gills,  and  the  animals  are  thought  to  have  been  aquatic,  possibly 
even  marine.  But  in  Carboniferous  genera  an  important  change  has  taken  place, 
in  that  the  covering  plates  have  closed  over  the  lamellae  of  the  gills,  leaving  only 
slit-like  openings  called  Stigmata.  Breathing  in  these  forms  took  place  by  the 
admission  of  air  through  the  Stigmata  to  lung-books.     P.  nuntius  was  blind. 

Eoscorpius  Meek  and  Worthen  (Fig.  1514) ;  Isohuthus  Fritsch  ;  and  Cyclophthalmus 
Corda,  are  exaraples  of  Carboniferous  Scorpions.  Eoscorpius  does  not  differ  in  any 
important  respect  from  living  forms,  and  appears  to  have  been  quite  as  liiglily 
organised.  According  to  Fritsch  the  order  Scorj^ionida  attained  its  acme  during  the 
Carboniferous  and  snbsequently  declined.  Imperfect  remains  have  been  found  in  the 
Trias  of  Warwickshire,  and  a  species  of  Tityus  Koch  occurs  in  Oligocene  amber. 

The  Order  Pedipalpida  (Whip-scorpions,  etc.)  has  two-jointed  retrovert  chelicerae, 
and  six-jointed,  retrovert  or  chelate,  raptorial  pedipalpi.     The  first  pair  of  legs  is 


Fig.  1514. 
Eoscorpius  carhonarius  Meek  and  Worth.     Goal  Measiires  • 
Mazon  Creek,  Illinois.    A,  Dorsal  aspect  of  sonia,  i/i-    B,  Pecten 
or  "  comb, '  enlarged. 


Fig.  1515. 

Geralinura  bohemica  (Kusta). 
Goal  Measures ;  Rakonitz,  Bohemia. 
Vi  (after  Kusta). 


yery  long  and  modified  as  tactile  organs.  Coxae  of  second  pair  of  legs  placed  behind 
those  of  the  pedipalpi,  while  the  small  coxae  of  the  first  pair  are  widely  separate 
and  situated  above  and  external  to  the  former.  Abdomen  segmented,  movably  jointed 
to  the  cephalothorax  ;  last  two  or  three  Segments  small,  annular,  either  with  or  with- 
outa  segmented  whip.  To  this  order  belong  Geralinura  (Fig.  1515)  and  Graeophonus 
Scudder,  from  the  Carboniferous  ;  Stenarthron  Haase,  from  the  Upper  Jurassic  Litbo- 
giaplnc  Stone  of  Bavaria  ;  and  Phrynus  Latreille,  which  occurs  Tertiarv  and  Recent. 

found  m  Southern  Italy,  Sicily,  and  Texas.     It  has  no  fossil  representatives. 

The  extmct  order  Kustarachnida  is  represented  by  a  Single  family,  comprising 


SUBCLASS  II 


EMBOLOBRANCHIATA 


789 


Fig.  1516. 

Kustarachne  tenuipes 
Scudder.  CoalMeasures; 
Mazon  Creek,  Illinois. 
3/2  (after  Petrunkevitch). 


Fig.  1517. 

Protosolpuga  carbonaria  Pet- 
runk.  Goal  Measures ;  Mazon 
Creek,  Illinois.  1/1  (after  Pet- 
runkevitch), 


the  solitary  geiiiis  Kustarachne  Scudder  (Fig.    1516),  of  wliicli  iliree  Carbon iferous 
species   have   been   described.       Chelicerae    not    observed  ;    pedipalpi    chelate,   tlieir 
coxae   fused    solidly   together ;  ,ab- 
domen    segmented,    pediciüate,   the 
terminal  segment  annuliforni  ;  legs 
long  and  slender; 

The  Order  Solpugida  (Solifugae) 
has  the  head  fused  with  the  first 
thoracic  segment,  all  the  remaining 
thoracic  segments  being  free.  Cheli- 
cerae chelate  :  pedipalpi  pediform  ; 
abdomen  segmented  ;  resj)iration  by 
means  of  tracheae  ;  trochanters  two- 
jointed ;  coxae  and  trochanters  of 
the  fourth  pair  of  legs  with  a  row 
of  characteristic  "  maleoli,"  Proto- 
solpuga Petrunk.  (Fig.  1517)  is 
known  from  the  Carboniferous. 
Modern  forms  are  subtropical. 

The  Order  Ricinulei  or  Podo- 
gonida,  is  represented  in  the  modern  fauna  by  two  tropical  genera,  and  includes  also 
a  few  Carboniferous  forms.  Head  and  thorax  fused,  forming  a  cephalothorax,  in 
front  of  which  is  a  movable  plate  called  the  "  cucuUus."  Abdomen  composed  of 
nine  segments,  but  so  united  with  the  cephalothorax  that  the  first  and  second 
abdominal  segments  are  not  visible.     The  three  hindmost  segments  are  small,  annular, 

forming  a  short  "  tail." 
Chelicerae  are  two- 
jointed,  chelate;  pedi- 
palpi chelate ;  tro- 
chanter  of  first  and 
second  pairs  of  legs 
two-jointed ;  the  third 
pair  of  legs  in  the 
male  is  modified  as  a 
copulatory  apparatus  ; 
eyes  absent  in  both 
sexes.  Polyochera 
Scudder  (Fig.  1518); 
and       Curculioides 


J'olyochera  pviiitulafa  ISciul.    Goal  Measures  ; 


Mazon  Creek, 
vitch). 


JUiuois.      a/2  (after    Petrunke- 


FiG.  1519. 
Chclifer  liemprichi  Menge. 


Oiigocene;  Baitic  amber.  9/i.  Buckland  are  Carboni- 
ferous examples. 

The  Order  Pseudoscorpionida  also  known  as  Chernetidea  or  Chelonetni  (False 
Scorpions),  is  chiefly  Recent,  with  no  fossil  representatives  older  than  the  Tertiary. 
In  this  group  the  head  is  fused  with  the  thorax,  the  abdomen  is  segmented  and 
broadly  joined  to  the  cephalothorax.  Chelicerae  chelate,  with  openings  on  the 
movable  finger  for  the  ducts  of  the  spinning  glands ;  pedipalpi  chelate.  The  Recent 
genus  Chelifer  Geoffr.  (Fig.  1519)  occurs  also  fossil  in  Baitic  amber. 

The  Order  Araneida  or  Araiieae  (Spiders)  has  numerous  fossil  representatives, 
the  earliest  of  which  appear  in  the  Carboniferous.  Head  and  thorax  fused  ; 
chelicerae  two-jointed,  retrovert ;  pedipalpi  pediform,  tlieir  terminal  Joint  in  the 
male  modified  as  a  copulatory  organ  ;  abdomen  segmented  only  in  the  most  primitive 
suborder,  anteriorly  constricted  and  movably  united  with  tlie  cephalothorax  ;  usually 
six  spinnerets  present  on  the  abdomen,  but   their  number   may  vary  between  two 


ARTHROPODA 


PHYLUM  VII 


790 

and  eight.  Arthrohjcosa  Harger  (Fig.  1520),  and  Protolycosa  Roemer  (Fig.  1521),  are 
CurboiiiftTon^;  examples,  but  tlie  majority  of  forms  are  known  from  Oligocene  amber 
fouii.l  Oll  llic  slu.ivs  of  the  Baltic  in  Fast  Prussia.     Mizalia  Koch  (Fig.  1522)  is  an 


Fig.  1520. 

Arthrolycosa   antiqua    Harger.      Goal   Measures 
Mazon  Creek,  Illinois,    i/i  (after  Petrunkevitch). 


Fig.  1521. 

Protolycosa  anthra- 
cophila  Roemer. 
Goal  Measures ; 
Myslowitz,  Silesia. 
(after  F.  Roemer). 


Fig.  1522. 

Mizalia  rostrata  Koch  and 
Berendt.  Oligocene ;  Baltic 
amber.    3/,. 


Fig.  1523. 

A  ttoides  eresiformis  Brongt. 
Oligocene ;  Aix  in  Provence. 
lO/x  (after  Brongniart). 


Fig.  1524. 

Thomisns  oeningensis 
Heer.  Fresh water  Mio- 
cene ;  Oeningen,  Baden. 
'•2/1  (after  Heer). 


example  from  the  latter  locality ;  Attoides  Brongt.  (Fig.  1523)  occurs  in  the  fresh - 
water  Oligocene  marls  of  Aix  in  Provence,  and  Thomisus  Walck.  (Fig.  1524)  in 
similar  deposits  of  Miocene  age  at  Oeningen,  Baden.     The  Upper  Oligocene  lignites 

of  Rott,  near  Bonn,  Ger- 
many,  and  the  Miocene  fresh- 
water  strata  of  Florissant, 
Colorado,  have  also  yielded 
remains  of  this  order.  Among 
Eocene  localities,  from  which 
fossil  Spiders  have  been  ob- 
tained,  should  be  mentioned 
the  Green  River  beds  of 
Wyoming,  and  the  strata  at 
Quesnel,  British  Columbia. 
The  known  species  of  fossil 
Spiders  aggregate  about  250. 
The  Order  Anthraco- 
marti  is  confined  to  the 
Paleozoic,  and  is  perhaps 
ancestral  to  the  Pedipalps 
and  Opiliones,  being  in  some 
Its  distinguishing  characters  are  as  follows  : 


Fio.  ] 


•'^  M.'as.uvs;  Xeu- 

ity.n-,  .>i.>-m;i.     Dorsal  aspoct. 
Vi  (after  Karsch). 


FlO.    VyOi 


Goal   M.,i 
land.      I) 


•  V'<-tncd  (Buckland). 
^  ,  <  <).ill)iookdale,  Eng- 
'   ■■i^l'i'ft,    shovving    ten 

i?'?\.    •'""'*^"^^  of  the  hind-bodv. 

Vi  (aftei  \Vood\\ard\ 


Kl\vc(.ai   them. 


J 


suBPHYLUM  II  MYEIAPODA  791 

head  fiised  with  the  thorax  ;  abdomen  segmented,  apparently  broadly  joined  to  the 
cephalothorax ;  between  the  tergites  and  steniites  one  or  two  rows  of  pleural 
sclerites ;  anus  witli  an  operculiim  wliicli  represents  the  tergite  of  the  eleventh 
Segment ;  chelicerae  not  known  ;  pedipalpi  short,  pediform  ;  legs  seven-jointed  with 
niovable  coxae  apparently  articulated  to  a  sternum.  Änthracomartus  Kartsch  (Fig. 
1525);  Brachypyge  and  Eophrynus  Wood  ward  (Fig.  1526)  ;  Maiocercus  and  Trigono- 
tarhus  Pocock  ;  and  Kreischeria  Geinitz  are  Carboniferous  genera. 

The  Order  Haptopoda  is  also  confined  to  the  Paleozoic.  Head  fused  with  the 
thorax  ;  abdomen  segmented,  broadly  joined  to  the  cephalothorax  ;  pedipalpi  short, 
pediform  ;  pleura  soft,  withont  sclerites ;  tarsus  of  the  first  pair  of  legs  seven-jointed. 
Plesiosiro  Pocock,  from  the  Carboniferous  of  England,  is  the  solitary  known  genus. 

The  Order  Phalangiotarbi,  like  the  two  preceding  Orders,  is  Paleozoic.  Head 
fused  with  the  thorax  ;  al)domen  broadly  joined  to  the  cephalothorax,  segmented, 
with  soft  pleura  devoid  of  sclerites  ; 
several  anterior  tergites  very  short,  wdth  a 
thickened  posterior  edge ;  anus  with  an 
operculum,  representing  the  tergite  of  the 
twelfth  Segment ;  chelicerae  not  observed  ; 
pedipalpi  short,  pediform.  Phalangiotarbus 
Haase ;  Geratarbus  Scudder  ;  and  Archi- 
tarhus{=  Geraphrynus)  Scudder  (Fig.  1527); 
Opiliotarhus  Pocock;  Discotarhus ^Vetruiik., 
etc.,  are  Carboniferous. 

The  Order  Phalangida  or  Opiliones 
(Harvest -Spiders)  has  many  fossil  repre- 
sentatives,  most  of  which  are  preserved  in 

Oligocene    amber.     Head   fused   with    the  -^  •  ^^ 

thorax  ;  abdomen  broadly  joined  with  the  Fig.  152Y. 

cephalothorax,  segmented,  the  anal  oper-  ArcUtarhus  rotundatus  Scudder  (=Geraphrynus 
pnlnm  ro-nrpcjpnf in»  fliP  tprcrifp  nf  tTiP  tpnfli  carbonaHus  Scudder).  Goal  Measures  ;  Mazon  Creek, 
culum  representing  tue  tergite  ol  tue  tentn    ^^^^^^^^^    un^er  surface.    i/i  (after  Petrunkevitch). 

Segment.     Chelicerae  three-jointed,  chelate; 

pedipalpi  pediform  ;  coxae  of  the  first,  often  also  of  the  second  and  tliird  pairs  of  legs 
with  maxillary  lobes  ;  one  pair  of  tracheae.  Nemastomoides  Thevenin ;  Dinopilio 
Fritscli ;  and  Protopilio  Petrunk,,  all  from  the  Carboniferous,  are  referred  to  this 
Order.  The  first-named  of  these,  however  {Nemastomoides  claveris  Thevenin),  may 
possibly  belong  to  the  Anthracomarti. 

The  Order  Acarina,  Äcari,  or  Rhynchostomi  (Mites,  Ticks,  etc.)  comprises  degenerate 
Arachnids  in  which  the  abdomen  is  usually  not  segmented  and  is  either  broadly 
joined  to  the  cephalothorax  or  completely  fused  with  it.  Coxae  of  pedipalpi  fused 
together ;  coxae  of  legs  widely  separate,  without  maxillary  lobes.  Numerous  fossil 
representatives  are  known  from  Oligocene  amber  and  Tertiary  freshwater  deposits, 
the  majority  of  species  being  referable  to  Recent  genera.  Through  the  Opiliones  this 
Order  appears  to  be  connected  with  the  Spiders. 


SuBPHYLUM  B.    Myriapoda  Latreille/ 

Tracheate    Arthropods    with    distinctly    separat ed    head    bearing    a    single   pair    of 
antennae,  and  a  soma  composed  of  numerous  {at  least  twelve)  fairly  similar  segments 

^  Literature  :  Fritsch,  A.,  Fauna  der  Gaskohle,  vol.  iv.  Prague,  1899-1901. — Orinnell,  F., 
Quateniary  Myriapods  and  Insects  of  California.  Univ.  of  Cal.  Publ.,  Dept.  Geol.,  1908,  vol.  v. — 
Koch,  0.  L.,  Die  Myriapodeu.  Regensburg,  1847. — Koch,  G.  L.,  and  Berendt,  J.  C,  Die  im 
Bernstein  bettndliclien  Crustaceen,  Myriapoden,  Arachniden  und  Apteren  der  Vorwelt.     Berlin, 


792  /  ARTHROPODA  phylum  vii 

which  are'ne/er  divided  into  tagmata  ;  there  are  two  or  three  pairs  of  mouth  appendages, 
and  num^röus  pairs  of  legs. 

The  time-honoured  division  of  Myriapods  into  the  Orders  commonly  known 
as  Centipedes  and  Millipedes  {Ghüopoda  and  Diplopoda),  plus  the  inore  recently 
established  groups  of  Pauropoda  and  Symphyla,  which  latter  have  no  fossil  repre- 
sentatives,  has  of  late  years  been  abandoned.  The  prevailing  modern  view  is  to 
regard  the  above-mentioned  groups  of  tracheate  Arthropods  as  independent  classes  of 
the  phylum  ;  and  the  reason  for  this  is  found  in  the  recognition  of  closer  affinities 
between  the  Chilopoda  (Centipedes)  and  the  Hexapoda  (Insects),  on  the  one  band,  than 
between  the  Chilopoda  and  Diplopoda  on  the  other.  According  to  the  modern  System 
the  older  fossil  Millipedes,  which  are  embraced  in  the  extinct  orders  Protosyngnatha 
and  Archipolypoda  of  Scudder,  fall  within  the  liniits  of  the  class  Diplopoda. 

For  practical  purposes,  however,  it  will  be  convenient  to  retain  the  designation 
Myriapoda  in  a  general  sense,  it  being  a  familiär  term,  and  the  number  of  fossil 
forms  with  which  the  paleontologist  has  to  deal  being  comparatively  limited.  The 
groups  of  which  Centipedes  and  Millipedes  are  the  most  important  members  are  here 
treated  as  classes,  conformably  to  the  view  which  assigns  them  equal  rank  with  the 
exclusively  Recent  Pauropoda  and  Symphyla.  Among  the  latter,  certain  genera 
agree  exactly  in  the  numerical  segmentation  of  the  body  with  an  isopod,  a  thysanuran, 
and  a  primitive  arachnid.  This  would  lead  to  the  inference,  as  pointed  out  by 
G.  H.  Carpenter,  that  "  all  the  Arthropodan  classes  must  be  derived  from  ancestors 
with  a  definite  number  of  segments,  and  the  development  of  a  large  number  of 
somites  in  such  forms  as  Julus,  Geophüus,  and  Äpus  must  be  regarded  as  a  secondary 
condition." 

Olass  1.     DIPLOPODA  Gervais  (Chilognatha  Latreille).     (Millipedes). 

Trunk  homonomously  segmented,  segments  usually  numerous  and  not  ßattened,  of  a 
variable  numher  {from  12  to  150),  and  the  majorüy  of  them  fused  pairivise,  each  tergite 
hearing  two  pairs  of  legs.  Read  with  one  pair  of  short,  seven-jointed  antennae,  one  pair 
of  mandihles,  and  one  or  two  pairs  of  maxillae.  No  Compound  eyes,  hut  numerous  ocelli 
usually  present. 

The  anterior  three  or  four  segments  of  the  soma  are  free,  with  a  single  pair  of 
legs  to  each  segraent.  The  anterior  pair,  or  both  pairs  of  legs  corresponding  to  the 
seventh  tergite  are  usually  modified  as  copulatory  organs 
(gonopods),  but  in  one  order  (Oniscomorpha)  it  is  the 
posterior  pair  of  legs  that  is  thus  modified.  A  pair  of 
genital  openings  is  present  at  the  base  of  the  legs  of  the 
second  segment.  Respiration  takes  place  by  means  of  either 
tufted  or  tube-like  tracheae  with  spiracles  at  the  base  of 
the  legs. 

Recent  Diplopoda  are  divided  into  eight  Orders.     At 
Fig.  1528.  least  five  of  the  modern  families  have  Tertiary  representa- 

0ÄnTl?S7tVE  t^'''  '^P'^^'^^y  '''  ^^^^^-  ^^^^«i^g  Tertiary  examples  may 
Bonn,  Germany.  i/j.  be  mentioned  the  foUowing :  Julus  Linn.  (Fig.  1528); 
_^^Gmspedmoma  Leach  ;  Euzonus  Menge  ;  Polyxenus  Latreille i 

Sof  kTi^rlsgg  Toi  ^;.f"^y^«^  Myriapods  from  the  Palaeozoic  rocks  of  ScTtlaml.  Proc.  Phys. 
iTu-t^dder    S^^^^^^^^^^  ^.,  Articles  on  Centipedes  and  Millipedes  in  Encycl.  Brit, 

loKu^iT       inn'/n^^^^^^  ^''^'-  ^^^^on  Soc.  Nat.  Hist.,   1873-90 

nanies  ba.sed  on  American  Insect7;;n7Araclmfd.  f~  .t''f '  J'  ^'  '^•'  ^"^'^'^^^^  "^"  ^^'  ^''''''' 
type  species.     Bull.  Amer.  U^Cmllm^^^  "^■'^'-  ^''''  ^"''^^'^°"^  ''  '^^ 


I 


SUBPHYLUM  II 


MYRIAPODA  \    \  793 


of   Julud   (tA 


and  Phryssonotus  Sciidder  {Lophonotus  Menge).  A  species  of  Julm  (JV  telluster 
Scudder)  occurs  ki  tlie  Green  River  Eocene  of  Wyoming,  and  another  in  the  Miocene 
freshwater  beds  of  Florissant,  Colorado. 

The  older  fossil  forms  are  referable  to  the  two  extinct  Orders  of  Scudder,  Proto- 
syngnatba  and  Arcbipolypoda.  The  former  of  these  approaches  closely  to  the  Recent 
Order  Pencillata,  and  is  represented  by  the  Carboniferous  genus  Palaeocampa  Meek 
and  Worthen.  The  second  of  these  Orders  comprises  three  families,  of  which  the 
Arcliidesmidae  resembles  the  Recent  Polydesmidae.     Ärchidesmus  Peach  (Fig.  1529); 


Fig.  1529.  Fio.  1530. 

Ärchidesmus  macnicoli  Peach.    Lower  Old  Red  Sand-  Euphoberia  armigera  Meek  and  Worth.    Goal 

stone  ;  Forfarshire,  Scotland.    i/i  (after  Peach).  Measiires  ;  Mazon  Creek,  Illinois,     i/i- 

and  Kampecaris  Page,  from  the  Old  Red  Sandstone  of  Scotland,  are  examples,  The 
family  Euphoberiidae  shows  sonie  resemblance  to  the  Julidae  of  the  present  fauna, 
but  the  dorsal  scuta  are  more  or  less  distinctly  divided  into  two  portions  corresponding 
with  the  pairs  of  legs.  Among  Carboniferous  genera  belonging  to  this  family  may 
be  mentioned  the  following  :  Äcantherpestes  and  Euphoberia  Meek  and  Worthen 
(Fig.  1530);  Ämijnilispes  and  Eileticus  Scudder.  Äcantherpestes  is  regarded  by 
Scudder  as  probably  amphibious,  and  attains  the  relatively  enormous  length  of 
20  cm.  {A.  giganteus  Baldwin).  The  family  Archiulidae  is  represented  in  the 
Carboniferous  by  Trichiulus  and  Archiulus  Scudder,  and  Xylohius  Dawson.  One 
Mesozoic  species,  Julopsis  cretacea  Heer,  from  the  supposed  Cretaceous  of  Greenland, 
is  of  doubtful  ordinal  position,  but  may  belong  to  the  Arcbipolypoda. 

Olass  2.     OHILOPODA  Latreille.     (Centipedes). 

Body  more  or  less  ßattened  dorso-ventrally,  composed  of  a  variable  number  of 
Segments  {from  18  to  176),  with  a  single  pair  of  legs  to  each  segment.  One  pair  of 
segmented  antennae,  the  joints  being  at  least  fourteen  in  number,  one  pair  of  mandibles 
and  tum  pairs  of  maxillae.  First  pair  of  somatic  appendages  modified  as  powerful 
maxillipeds  with  poison  glands  emerging  on  the  terminal  claw  (toxognaths).  Last  pair 
of  appendages  (those  borne  by  the  antepenultimate  segment)  modified  as  copulatory  organs. 
Unpaired  genital  aperture  on  the  penultimate  segment.  Eyes  variable  in  number,  simple 
or  Compound  (Scutigera),  often  wanting.  Respiration  by  means  of  tracheae  with  either 
p)aired  spiracles  in  the  pleural  membranes  or  single  spiracles  in  the  median  dorsal  line. 

Recent  Chilopoda  are  divided  into  five  Orders,  three  of  which  have  Tertiary 
representatives,  esjDecially  in  amber,  and  in  the  freshwater  deposits  of  Aix  in  Provence. 
The  following  true  Chilopod  genera  are  known  from  the  Tertiary  :  Cermatia  Rossi  ; 
Scolopendra  Linn.  ;  Lithobius  and  Geophilus  Leach.  The  older  fossil  remains  cannot  be 
positively  referred  to  any  of  the  five  existing  Orders.  By  Scudder  they  were  assigned 
to  two  extinct  families,  named  by  him  Gerascutigeridae  and  Eoscolopendridae. 
The  former  of  these  includes  the  genus  Latzelia  Scudder,  and  the  latter  the  genera 
Palenarthrus  and  Ilyodes  Scudder,  all  from  the  Coal  Measures  of  Illinois. 

[The  text  for  the  preceding  chapters  on  Embolobranchiata  and  Myriapoda  has  been  revised 
by  Dr.  Alexander  Petrunkevitch,  of  Yale  Uiiiversity. — Editok.] 


794 


ARTHEOPODA  phylüm  vii 


/BüBPHYLUM  C.     Insecta  (Hexapoda).     In'sects.^ 

Tracheate,  Arthropods  with  hodtj  at  maturity  consisting  of  a  distind  head,  thorax 
and  abdorrten.  Head  provided  with  one  pair  of  antennae,  one  of  mandibles,  and  two  of 
maxillae.  Thorax  composed  of  three  segments,  each  supplied  with  a  pair  of  legs,  and  the 
second  and  third  segments  also  usually  carrying  a  pair  of  wings  on  fheir  dorsal  surfaces 
in  the  adult  state.  Abdomen  composed  of  several  (commonly  ten)  distinct  segments,  and 
usually  without  leg-like  appendages.     Development  usually  through  metamorphic  stages. 

No  undovibted  remains  of  Insecta  are  known  from  strata  older  than  tlie 
Cai'boniferoiis,  but  in  the  Goal  Measiires  and  Perniian  a  considerable  variety  of 
winged  forms  has  been  detected,  in  both  Europe  and  North  America.  These  earlier 
Insects  appear  to  be  more  generalised  than  are  the  post-Paleozoic  forms,  and  the 
majority  are  referred  by  Handlirsch  to  Orders  distinct  from  those  occurring  in  Mesozoic 
and  later  formations.  But  one  order,  the  Blattoidea,  seems  to  have  survived  from 
Paleozoic  times  onward  to  our  own  day.  The  primitive  extinct  order  Palaeodictyop- 
tera  is  regarded  as  the  ancestral  stock  which  gave  rise  to  the  other  Paleozoic  Orders, 
and  from  the  latter  in  turn  have  originated  the  modern  Insect  groups. 

Although  it  is  clear  that  strangely  differentiated  forms  occurred  among  the 
different  Insect  groups  as  early  as  the  Carboniferous,  yet  it  has  been  conclusively 
shown  that  this  differentiation  had  little  depth,  and  that  it  is  only  through  Mesozoic 
and  later  descendants  that  we  have  any  clue  to  a  wide  Separation  of  the  original 
Paleozoic  forms.  Among  the  latter,  the  neuration  of  the  wings,  though  diversified, 
had  yet  a  far  greater  homogeneity  than  is  found  now,  or  than  existed  during  Mesozoic 
time,  from  the  Trias  onward.  The  fore  wings  of  wh'atever  type  were  as  diaphanous  as 
the  hind,  and  could  never  (as  in  most  of  their  descendants)  properly  be  called  tegmina. 
The  wings  of  the  Protodonata  of  Brongniart  had  indeed  a  superficial  resemblance 
to  those  of  living  Odonata  in  shape,  reticulation,  and  sweep  of  the  veins.  But  in 
fundamental  neuration  they  were  altogether  different,  and  no  trace  is  to  be  discovered 
of  those  characteristic  features  of  the  Odonata,  such  as  the  nodus,  triangle  and 
pterostigma,  which  appear  fully  elaborated  in  the  Mesozoic  species. 

"The  wings,  broadly  speaking,  may  be  said  to  be  three-margined.  The  margin 
that  IS  anterior  when  the  wings  are  extended  is  called  the  costa,  and  the  edge  tliat  is 
then  most  distant  from  the  body  is  the  outer  margin,  while  the  limit  that  lies  along 
the  body  when  the  wings  are  closed  is  the  inner  margin. 

"The  only  great  order  of  insects  provided  with  a  single  pair  of  wings  is  the  Diptera, 
and  in  these  the  metathorax  possesses,  instead  of  wings,  a  pair  of  little  capitate 
bodies  called  halteres  or  poisers.  In  the  great  order  Coleoptera,  or  beetles,  the 
anterior  wmgs  are  replaced  by  a  pair  of  horny  sheaths  that  close  together  over  the 
back  ot  the  insect,  concealing  the  hind  wings,  so  that  the  beetle  looks  like  a  wingless 
insect ;  in  other  four-winged  insects  it  is  usually  the  front  wings  that  are  most  useful 
in   night.     In  the   Orthoptera   the  front   wings  also  differ  in  consistence  fmm  the 

rnZriTi^T  TJ^  .  *^'^^^'  in  repose,  and  are  called   the  tegmina."      (Sharp, 
Cambridge  Natural  History,  vol.  v.)  b  \         i^, 

lusL^l^TH''tlS£r''Z^     '"  *'i  V'7''S  ™"^'^  -ell-known  publications  on  fossil 
1906-8.     See  IL  nZd^Ch^.  ^  Ta  ^^•^-  ^^''<^^i^'<^^   Die  fossilen  Insekten,  Leipzig, 

•■'■'••  H..]in„     Brues    Bufr    ?W1       ll     ^^^^tribuüons  one  shonld  consult  the  writings  of  Agnns 

TlH-  n„w,  Z^^  S^'^lf^^'^'  Ulmer,  Wickham,  and  oth( 


lers. 


/^rj!/'.\'/7'/''' p"V''  \^'^  '"'"''*  '''''"'''  °^  Commentry  are  contained  in  the  follow- 
«tc.  Saint-  |.:t  ienne, '  1893  ^ ~-^Mry\'n-lr  i^""  m  """  ''T''' ''  ^'^i^^^ire  des  insectes  des  temps  primaires, 
l-ilh.rde<^..n.ntry(Ailier).Tn;a^y,~:l;;^^^^^^^^^^^  '^^'^'^^  ^"  '^''^'^ 


I 


\ 


SüBPHYLüM  III  INSECTA  \         ^  795 

\ 

Among  the  Orthopterons  Insects  of  the  British  series  of  Carboniferl^us  rocks  are 
a  niim])ei'  of  forms  allied  to  cockroaclies,  and  nodiiles  of  the  same  age  contain  wings  of 
Palaeodictyoi3terous  and  allied  Insects,  some  of  them  showing  colour  bands  (Brodjea). 
At  Comnientry  (Allier),  France,  is  found  the  riebest  deposit  of  Carboniferous"' Insects 
in  the  world,  and  this  faiina  has  been  ably  investigated  by  Charles  Brongniart 
(1893)  and  later  writers.  Very  numerous  fossil  remains  are  known  from  diiferent 
Mesozoic  and  Cenozoic  horizons.  The  Insects  found  in  the  English  and  German 
Lias  are  for  the  most  part  small  and  insignificant,  bat  there  are  known  a  moderate- 
sized  dragonfly,  and  also  a  few  Coleoptera.  Various  remains  occur  also  in  the  Stones- 
field  Slate,  Purbeck,  Wealden,  Bagshot  Beds  (Upper  Eocene),  and  Bembridge  Beds 
(Oligocene)  of  England.  Insects  are  well  represented  in  the  Lithographie  Stone 
(Kimmeridgian)  of  Bavaria ;  in  fresh water  Oligocene  deposits  of  Aix  in  Provence, 
and  especially  in  Baltic  amber  of  the  same  age  from  East  Prussia ;  in  the  Miocene 
brown  coal  of  Rott  near  Bonn ;  in  the  Miocene  lacustrine  deposits  of  Oeningen, 
Baden,  on  Lake  Constance ;  and  in  similar  deposits  of  Florissant,  Colorado,  also 
of  Miocene  age.  Many  Insects  also  come  from  the  Miocene  deposits  of  Radoboj 
in  Croatia,  and  from  the  Indusial  limestone  of  Lower  Miocene  age  from  Offenbach. 
There  is  considerable  reason  to  suppose  that  Insects  were  more  numerous  in  species 
during  Tertiary  times  than  they  are  at  the  present  day. 

In  the  System  here  adopted  the  winged  or  wingless  condition  is  made  the  basis 
for  dividing  Insects  into  two  classes,  Pterygogenea  and  Äpterygogenea.  The  former 
of  these  comprises  forty  Orders,  thirteen  of  which  are  entirely  extinct.  The  lowly 
organised  class  of  apterous  Insects  comprises  four  Orders,  three  of  which  have  Tertiary 
representatives  as  well  as  Recent,  and  the  remaining  order  is  without  known  fossil 
representatives. 

If  the  opinion  of  Lankester  and  Börner,.that  the  primitive  Insects  have  a  special 
afhnity  with  the  Isopoda,  be  accepted,  the  discovery  of  Oxyuropoda  in  the  Devonian 
of  County  Kilkenny,  Ireland,  becomes  of  particular  interest  (see  ante,  p.  757).  In 
the  view  of  G.  H.  Carpenter,  a  more  general  relationship  between  Insects  and 
Crustacea  seems  probable,  so  that  this  Devonian  Isopod  genus  and  the  lowly  organised 
Pterygote  order  of  Palaeodictyoptera  must  be  regarded  as  having  each  advanced  along 
different  lines  of  specialisation  from  their  common  ancestors.  The  common  stock 
from  which  both  Crustacea  and  Insecta  are  descended  must  surely  have  been  Arthro- 
pods with  undifferentiated  trunk-segments,  yet  on  the  whole,  resembling  primitive 
Crustaceans  in  structure,  and  possibly  not  very  remote  from  Trilobites. 

Olass   1.     PTERYGOGENEA  Brauer. 

Insects  normally  winged  in  the  adult,  or  secondarily  wingless,  with  faceted  eyes,  and 
ahdomen  usually  with  nine  or  ten  distinct  Segments. 


t  Order  1.     PALAEODICTYOPTERA  Goldenberg. 

Head  moderately  large,  rounded,  ivith  siw/ple  antennae,  mouth  parts  adapted  for 
biting,  and  well-developed  jaws.  Two  pairs  of  wings,  suhequal  in  size,  of  similar  form 
and  primitive  venation,  incapable  of  heing  folded  hacJcward  over  the  ahdomen  ;  sometimes 
a  rudimentary  third  pair  present  on  the  first  thoracic  segment  Ahdomen  consisting  of 
ten  nearly  homonomous  segments  which  often  exhihit  pleural  lohes.  Terminal  segment 
often  with  much  elongated  cerci.      Thoracic  legs  similar. 

In   this   Order   the  wing  structure  is  very  primitive  (Fig.    1531),  corresponding 

t  Tills  sigu  is  iised  tliroiigliout  tlie  following  pages  to  indicate  that  the  ßystematic  group  referred 
to  is  extiuct. 


796 


ARTHROPODA 


PHYLUM  VII 


viTV  iH'.'irly  1( 
less  irro'nilar  : 


llie  hypothetical  type, 
tlie  anal  lobe  Is  not 


Tlie  cross-veins  are  numerous  and  more  or 
by  a  fold  ;  the  anal  veins  are  always 
well  developed,  more  or  less  branclied, 
and  curved  regularly  backward  to  tlie 
posterior  margin ;  and  there  is  no 
anal  fold  nor  fan  -  like  plaitings. 
Larvae  are  similar  to  the  imago. 

The  Palaeodictyoptera  are  best 
regarded  as  a  generalised  group  of 
very  primitive  Organisation,  and  as 
.  the  probable  progenitors  of  all  winged 
Insects.  They  are  restricted  to  the 
Paleozoic,  and  occiir  in  various 
European  and  North  American 
localities.  There  are  about  120 
known  species,  the  majority  of  which 
are  European,  and  about  one-fourth  of  this  nuniber  being  found  in  the  Carboniferous 
of  the  United  States  and  Canada.  Six  species  are  known  from  the  Pottsville,  ten 
from  the  Kanawha  and  Little  River  groups,  eleven  from  the  Allegheny,  one  from  the 
Conemaugh,  and  the  remainder  of  American  forms  from  the  Productive  Goal  Measures, 
Many  of  these  Insects  attain  considerable  size.  The  foUowing  named  families  liave 
been  distinguished  : 

Dictyoneuridae,  of  which  the  genus  Stenodictya  Brongn.  (Fig.  1532)  is  an  example. 


Fig.  1531. 
Diagram  of  the  neuration  of  a  primitive  insect  wing,  one 
of  the  Palaeodictyoptera.  The  principal  longitudinal  veins 
are  connected  by  a  network  of  cross  -  veins.  c,  Costa ;  sc, 
Subcosta ;  r,  Radius ;  rs,  Radial  sector ;  m,  Media ;  cu, 
Cubitus  ;  a,  Anal  veins  or  nervures  (after  Handlirsch). 


Fig.  1532. 

rJUa^^r^"  ^^f"-  ßfong»-  Stephanian  (Upper  Carboni- 
ferous) ;  Commentry,  Allier,  France.  The  antennae  ocelli  and 
tarsi  are  reconstructed.    2/3  (after  Handlirsch).  '  ^ 


Fig.  1533. 
Eublephis  danielsi  Handl.   Goal  Measures  ; 
Mazon  Creek,  Illinois.    The  antennae.  ocelli 
and    tarsi    are    reconstructed.      2/^ '  (after 
Handlirsch). 


L  thoZ  tl  '  /^Wtüidae,  HypermegetMdae,  Mecy>opteridae,  Syntonopteridae, 
Fouaul  r;..^^"T?^''^  Homoipteridae,  Homothetidae,  Heolidae,  Broyeriidae 
f~nted  ,':Ä""'f%«P''^Pt«"dae,  Lamproptüidae,  Polycreagrida;,  Eubleptida 


t  Order  2.     MIXOTERMITOIDEA  Handlirsch. 


I 


SUBPHYLUM  III 


INSECTA 


797 


Tliia  Order  is  probably  an  early  aberrant  offshoot  of  the  preceding  group,  and  is 
known  from  two  genera.    Mixotermes  Sterzel  (Fig.  1534)  occurs  in  tbe  Coal  Measures  of 


\ 


Mixotermes  lugauensis  Sterzel.  Coal  Measures  ; 
Lugau,  Saxony.  Fore  wing.  2/j  (after  Hand- 
lirscli). 


Fig.  1535. 

Recula  parva  Schlechten.  Coal 
Measures  ;  Wettin,  Saxony.  Fore 
wing.    ^/i  (after  Handlirsch). 


Saxony,  and  Geroneura  Matthew  in  tlie  Little  Eiver  group  (approxiiiiately  eqnivalent 
to  tlie  Kanawha  series)  of  New  Brunswick. 

t  Order  3.     RECULOIDEA  Handlirsch. 

An  early  aberrant  offshoot  of  the  Palaeodictyoptera,  with  peculiarly  specialised  wing 
neuration,  and  approaching  in  some  respects  to  the  Protorthoptera  and  Protohlattoidea. 

Tliis  Order  was  proposed  in  a  provisional  sense  to  incliide  the  single  genus  Recula 
Handlirsch  (Fig.  1535),  from  the  Coal  Measures  of  Saxony. 

t  Order  4.     PROTORTHOPTERA  Handlirsch. 

Wing  pairs  of  unequal  size,  capahle  of  being  folded  backward  over  the  abdomen,  and 
with  more  complicated  venation  than  in  the  preceding  types,  approaching  in  some  respects 


Fio.  1536. 

Spaniodera  amhnlans  Handl.  Coal 
Measures ;  Mazon  Creek,  Illinois,  i/j 
(after  Handlirsch). 


Fio.  1537. 

Oedischia  williamsoni  Brongn.  Stephanian ; 
Comnientry,  France.  A  forerunner  of  true  Locus- 
toids,  with  long  antennae  and  hind  legs  adapted 
for  springing.     '■^/■^  (reconstructed  by  Handlirsch). 


that  of  the  modern  Locustidae.  Hind  wings  similar  to  the  front  pair,  but  with  larger  anal 
area^  marJced  off  by  a  fold.  Antennae  long  and  slender ;  mouth  parte  strong,  adapted 
for  biting.     Prothorax  often  elongated  or  saddle-shaped^  legs  similar  in  form,  the  third 


798  ARTHROPODA  phylum  vii 

pair  sometimes  elongated  and  adapted  for  springing ;  cerci  short  or  of  moderate  size ; 
abdominal  segments  without  lateral  lohes.  Females  of  some  species  with  a  well-developed 
ovipositor. 

This  Palet)zoic  group  is  apparently  intermediate  in  position  between  the  Palaeo- 
dictyoptera  and  Orthoptera  proper.  There  are  iipwards  of  ninety  known  species, 
about  twenty  of  wliich  occur  in  the  Goal  Measures  of  North  America,  and  forty  in 
the  Permian  of  Kansas.     The  following  named  families  have  been  distinguished  : 

Spanioderidae,  of  which  the  genus  Spaniodera  Handl.  (Fig.  1536)  is  an  example, 
Isclmoneuridae,  Cnemidolestidae,  Prototettigidae,  Homalophlebidae,  Protokollariidae, 
Schuchertiellidae,  Pachytylopsidae,  Caloneuridae,  Stenaropodidae,  Oedischiidae  (with 
well-developed  jumping  legs  as  shown  in  Oedischia  Brongn.)  (Fig.  1537),  Omalidae, 
Geraridae,  Sthenaroceridae,  Apithanidae,  Cacurgidae,  and  Narkemidae. 


Order  5.     ORTHOPTERA  Olivier. 

Mouth  parts  well  developed,  mandihulate}  Wings  unequal,  capahle  of  heing  folded 
backwards  over  the  abdomen.  Fore  wings  coriaceous^  with  numerous  cross-veins,  and  the 
principal  longitudinal  veins,  with  most  of  their  branches,  directed  towards  the  outer 
margin.  Bind  wings  thinner,  delicately  veined,  with  a  large,  plicated  anal  area. 
Prothorax  saddle-shaped  ;  hind  legs  generally  saltatorial. 

The  Orthoptera  are  Insects  of  comparatively  large  size.  The  largest  of  existing 
Insects  are  included  within  this  order,  and  none  of  its  members  is  so  small  as  are 
many  minute  representatives  of  other  Orders.  Modern  forms  include  grasshoppers, 
locusts,  green  grasshoppers,  katydids,  and  crickets. 

Suborder  A.     LOCUSTOIDEA  Leach.     (Locusts  and  Crickets). 

_  Cubital  area  in  the  fore  wings  of  the  male  (in  most  modern  forms)  modified  into 
stndulating  organs ;  anterior  tibiae  with  auditory  organ  ;  tarsi  three-  or  four-jointed ; 

antennae  long  and  slender,  consisting  of 
more  than  thirty  segments;  female  almost 
always  with  well  developed  ovipositor. 

The  earliest  known  members  of  this 
suborder  are  found  in  the  Lias  of 
Europe,  and  belong  to  the  extinct 
families  of  Locustopsidae  and  Elcanidae 
(the  latter  typified  by  the  genus  Elcana 
^'"•1538.  Giebel)    (Fig.    1538).      Apparently    no 

MeÄr'l\?uTLoclsYXÄ^  stridulating  organs  were  developed,  but 

oceiii  partiy  restored.    10/3  (after  Handiirsch).  ^   the    Elcanidae    lamellar   appendages 

tibiap  bv  mpoT,«  r.f     X.-  1  ^i^     •  ^^^^    ^^^^    observed    on    the    posterior 

Ä  wateTo.  li  .  ;  ^ects  were  probably  able  to  ambulate  on  the  surface 
Wae  The  T  T^  "^''V^'  "^^^^"^^  °^  ''^'  l^^-g  Tridactylidae  and 
hoS  and  Crvlbd.  '  P  VTs  ^'''j''^^'^  -«^«  true  Locustidae  (Gieen  Grass- 
SÄeand^^v^o^^^^  ""l'^    stridulating   organs,   and  the   families  Tri- 

aactyhdae  and  Giyllotalpidae  make  their  appearance  in  the  early  Tertiary.     Remains 

.na^ilfaClr  5,  rS^^Vi^iiircthüt'  IT'' •  ^^  TT*  ^^^^  ^"  ^^^^^^  «^  --^^^^-'  ^ 
that  some  of  the  mouth  Parts  are  0   a  tul  u^^^^^^^^  ^"""'^"'^     ^^  '  ^^''^^  *^'  ^"'"^  '""^^^^^^  ^"^P^^^'^ 

or  protects,  a  more  minuitdlel^^SCIp^^^^^^^^^^  '"  '  ^^°'^"^^'  "^'^^^  '''''''' 


SUBPHYLÜM  III 


INSECTA 


^99 


of  crickets  are  known  froni  the  Green  Eiver  Ecoene  of  Wyoming,  and 
are  found  also,  witli  locusts,  in  the  Miocene  lacustrine  beds  of 
Florissant,  Colorado.  Various  European  species  are  known  of  J)ry- 
madusa  Stein.  (Fig.  1539),  and  Gr ij II tis  lAiui.  (Fig.  1540).  _ 


Fig.  1539. 
Dryiriadusa  sjteciosa  (Heer).     Miocene  ;  Oeiiingen,  Baden,     -/i 


Suborder  B.     ACRIDIOIDEA  Handlirsch. 


Fig.  1540. 

Gryllus  macrocercus 
Germar.  Lower  Oli- 
gocene;  Baltic 
amber.  s/g  (after 
Germar). 


(Grasslioppers). 

Stridulating  organs  situated  in  the  hind  femora  and  a  modified  longitudinal  vein  of 
the  fore  wings.  Äuditory  organ  on  the  side  of  the  ßrst  abdominal  segment.  Antennae 
short,  composed  of  less  than  thirty  Segments.  Tarsi  short,  three-jointed.  No  exserted 
ovipo'sitor  in  the  female. 


Fig.  1541.  * 

Tyrbula  russelli  Seudder.  Miocene  lake 
beds ;  Florissant,  Colorado,  s/g  (after 
Seudder). 

Tills  is  a  group  of  com- 
paratively  late  origin,  and  is 
derived  in  all  probability  from 
the  Locnstopsidae  or  siniilar 
lociistoid  ancestors.  Grass- 
hüp})crs  are  known  from  the 
Green  Kiver  Eocene  of  Wyom- 
ing, and  from  the  freshwater 
Miocene  of  Florissant,  Colorado, 
and  elsewliere.  Tyrhula  (Fig. 
1541)  and  Nanthacia  Seudder, 
etc.,  are  examples. 


Fig.  1542. 

Chresmoda  obscura  Germar.     Tjithographic  Stone  (Upper  Jura) ; 
Solenhofen,  Bavaria.     -i/g  (after  Handlirsch). 


Order  6.     PHASMOIDEA  Leach.     (Walking-sticks,  Leaf  Insects,  etc.) 

Body  usually  long  and  slender,  mouth  parts  orthopteroid,  fore  wings  rarely  well 
developed,  loithout  stridulating  organ,  and  without  visihle  demarcation  hetween  the 
cubital  and  anal  areas.  Hind  wings  loith  large,  folded  anal  lohe;  hind  legs  not 
saltatorial,  usually  long  and  elender  like  the  other  pairs.  Gerd  short,  genital  appendages 
of  the  female  not  prominent,  tarsi  five-jointed. 

Here  is  placed  the  Upper  Jurassic  genus  Chresmoda  Germar  (Fig.  1542),  which, 


800 


ARTHROPODA 


PHYLÜI*  VII 


a<  ina.rated  by  tlie  stnictnre  of  its  legs,  probably  lived  on  tbe  snrface  of  the  water 
as  do  luodern  Gerridae.  True  terrestrial  Phasmoidea  occiir  rarely  in  Baltic  amber 
and  in  the  Miocene  lake  beds  of  Florissant,  Colorado.  An  example  from  tlie  latter 
locality  is  Agathemera  rechisa  Scudder. 


Order  7.     DERMAPTBRA  De  Geer.     (Ear-wigs,  etc.) 

Flat-hodied  running  Inseds  with  prognathous,  orthopteroid  mouth  parts ;  antennae 
simple,  consisting  of  from  ten  to  thirty  segments.     Fore  wings,  when  present,  very  feebly 

developed,  and  forming  sJiort,  coriaceous  tegmina. 
Hind  wings  longitudinally  and  transversely  plicated  in 
a  complex  fashion,  consisting  ahmst  ivliolly  of  the 
highly  specialised  anal  lohe.  Legs  similar,  with  three- 
jointed  tarsi ;  cerci  chelate. 

This  is  a  specialised  order,  wliicli  makes  its  first 
appearance  in  tbe  Tertiary  of  Europe  and  Nortli 
America.  Lahiduromma  Scudder  (Fig.  1543)  is  repre- 
sented  in  the  freshwater  Miocene  of  Florissant,  Colo- 
rado, by  about  a  dozen  species.  Forficula  Linn. 
ranges  from  the  Eocene  to  Recent. 


Fig.  1543. 

Lahiduromnia  exsulatum  Scudder. 
Miocene  lake  beds ;  Florissant,  Colo- 
rado,   a/j  (after  Scudder). 


Order  8.     DIPLOGLOSSATA  de  Saussure. 

Includes  the  apterous,  parasitical  family  Hemime- 
ridae,  living  in  Africa,  nnknown  in  the  fossil  state. 


Order  9.     THYSANOPTERA  Haliday.      (Physopoda  auct.). 

Small  terrestrial  Inseds  with  asymmetrical,  hypognathous,  suctorial  mouth  parts, 
short  antennae,  slender  wings  which  are  fringed  ivhen  present,  but  are  often  rudimentary 
or  wanting.     Legs  similar,  tarsi  with  one  or  two  joints,  termi-  j 

natedhy  avesicularstrudure;  cerci  reduced ;  genital  appendages  ^"t^"^ 

oj  the  female  forming  a  terehra.  ^fJ 

Several  genera   occur  in   the  Oligocene   and   Miocene  of 
Europe,  and  three  in  the  Green  River  beds  (Middle  Eocene)      .^ 
along  the  White  River  in  western  Colorado.     Thrips  Linn. ;    ^^ 
and  Palaeothrips  Scudder  (Fig.  1544)  are  examples. 

Fig.  1544. 

t  Order  10.     PROTOBLATTOIDEA  Handlirsch       i'aiaeothripsfossuis  smdder. 

Green  River  beds  (Eocene); 

Insects  usually  attaining  considerahle  size.  Read  not  con-  ^''"-  '''1^  ^^'''' ^''''^^''^■ 
cealed  heneath  the  prothorax,  with  orthopteroid  mouth  parts,  and  simple,  numerously 
jomted  antennae.  Fore  wings  usually  with  multifurcate  principal  veins  and  numerous 
cross-vetns;  suhcosta  well  marhed ;  anal  area  distinctly  limited  by  a  furrow,  anal  veins 
mostly  recurved.  Hind  wings  with  a  distinct,  enlarged,  and  folded  anal  lobe.  Wings 
capable  of  bemg  folded  over  the  abdomen,  and  the  forward  pair  overlapping  the  hinder. 
Legs  non-saltatonal,  the  first  pair  som,etimes  robust  and  raptorial.  Abdomen  rarely 
slender  generally  more  or  less  flattened ;  cerci  distinct ;  female  sometimes  with  a  short 
ovipositor. 


This   is  an   exclusively   Paleozoic   order,    intermediate   in   position   between   the 


I 


SUBPHYLUM  III 


INSECTA 


801 


Palaeodictyoptera  and  the  true  cockroaclies  and  soothsayers  (Blattoidea  and  Mantoidea) 
of  later  date.  The  less  specialised  members  of  this  order  are  very  similar  to  those  of 
the  parallel  group  Protorthop tera. 

The  Protoblattoidea  are  well  represented  in  the  Carboniferous  and  Permian  of 
Eiirope  and  North  America  by  the  following  named  families  : 

Stenoneuridae,  Protophasmidae  (typified  by  the  genus  Protophasma  Brongn.) 
(Fig.  1545),  Eoblattidae,  Oryctoblattinidae,  Aetophlebidae,  Cheliphlebidae,  Eucaenidae 


Fig.  1545. 

Protophasma  dumasi  Brongn.  Stephanian ; 
Commentry,  France.  Antennae,  ocelli,  tarsi  and 
cerci  restored  from  analogy.  4/g  (after  Hand- 
lirsch). 


Fig.  1546. 

Eucaenus  ovalis  Scudder.  Goal  Measures  ;  Mazon 
Creek,  Illinois.  Antennae,  ocelli  and  tarsi  recon- 
structed.    •i/g  (after  Handlirsch). 


(typified  by  the  genus  Eucaenus  Scudder)  (Fig.  1546),  Gerapompidae,  Adiphlebidae, 
Anthracothremmidae,  and  (?)  Cnemidolestidae. 


Order  11.     BLATTOIDEA  Handlirsch.     (Cockroachesi). 

Head  deßexed,  often  entirely  concealed  from  ahove  hy  the  large  shield-like  pronotum ; 
with  orthopteroid  mouth  parts  and  long,  numerously  jointed  antennae.  Legs  similar, 
luith  five-jointed  tarsi  and  long  coxae.  Fore  wings  or  tegmina  more  coriaceous  than  the 
hinder  pair,  and  more  frequently  preserved ;  they  are  capahle  of  overlapping  ahove  the 
ahdomen ;  their  suhcostae  are  more  or  less  reduced,  and  the  anal  area  is  distinctly 
separated  hy  a  curved  furrow.  Hind  wings  with  an  enlarged,  folded  anal  lohe. 
Ahdomen  short  and  hroad,  provided  with  cerci,  hut  without  visihle  female  genital 
appendages. 

This  order  includes  the  majority  of  Paleozoic  Insects,  upwards  of  300  species 
being  known  from  North  American  strata,  a  still  larger  number  from  European  rocks 
and  a  few  from  the  Carljoniferous  of  India.  About  80  Jurassic  species  have  been 
described,  half  as  many  Tertiary,  and  we  are  acquainted  with  about  1200  Recent 
species.  In  the  most  primitive  family,  the  Archimylacridae,  which  includes  more 
than  one-third  of  the  American  Paleozoic  species,  the  neuration  still  resembles  in  the 
main  the  Palaeodictyopteroid  type.  Highly  characteristic  of  this  family  is  the 
condition  of  the  long  subcosta  or  mediastinal  vein  of  the  tegmina,  which  sends  off  a 
large  number  of  branches  to  the  costal  margin,  either  pectinate  or  arranged  in  groups, 
but  never  issuing  ray-like  from  the  base  of  the  wing. 

1  Scudder,  S.  H.,  Revision  of  the  American  fossil  Cockroaches.     Bull.  U.S.  Geol.  Surv.,  no.  124, 
1895. — Schlechtendal,  D.  von,  Über  die  Karbon-Insekten  und  Spinnen  von  Wettin.    Leipzic,  1913. 
VOL.  I  3  F 


802 


ARTHROPODA 


PHYLÜM  VII 


beeil    derived   a   iiumber   of   more 


MediaslinaL 

Scapidar 

fjrterriomedicai 

i 


Anal  Veins 
Internomedian 


Froiu   this  generalised   stock    liave   proLably  -^     -,     ,.       n     i   Ar 

specialised  faniiL,  also  limited  to  tlie  Paleozoic  (Upper  Productive  Goal  Measures 
A  and   Permian),   among   which   may 

be  mentioned  tlie  followiiig  : 

Spiloblattiiiidae,  with  smootli 
fenestrated  Spaces  between  the  bor- 
dered  loiigitudiiial  veins  of  the 
tegmina  ;  Mylacridae,  with  the  sub- 
costal  branches  giveii  off  from  a 
common  point  of  origin  at  the  base 
(Fig.  1548,  C);  Poroblattinidae 
and  Neorthroblattinidae,  with  a 
very  short  siibcosta ;  Mesoblatti- 
nidae,  with  the  subcosta  forming 
only  a  calloiis  at  the  base  of  the 
anterior  border  ;  Pseiidomylacridae, 
Dictyomylacridae,  Neomylacridae, 
Pteridomylacridae,  Idiomylacridae, 
Diechoblattinidae,  and  Protere- 
midae. 

Tertiary  cockroaches  are  all 
referable  to  modern  families,  and 
are  probably  descended,  at  least  for 
the  greater  part,  from  the  Mesoblattinidae,  a  family  which  is  abundantly  represented 
in  Jurassic  rocks.     Many  larval  forms  and  even  ^^^'g  packets  of  cockroaches  are  foiiiid 


Fig.  1547. 
Neuration  of  one  of  the  tegmina  of  a  Paleozoic  Cockroach 
Asemoblatta  mazona  (Scud.),  from  the  Coal  Measures  of  Illinois. 
Tlie  veins  are  named  at  the  base  of  the  tegmen,  and  the  areas 
are  marked  along  the  margin.    2/j  (after  Scudder). 


Fi(i.  1548. 


specialised 


'''''""  'Äimiyfcrid  "''cTiLwf  ^ ?''•   ^t  ^^'  ^"'"*"^''  Archimylacrid.     B,  More  highly 
Arclumlyacrid.     L,  Mylacns,  typifying  the  Mylacridae.     Nervures  are  marked  as  in  Fig.  15 

fossil.     Specific  determinations  are  often  difficiüt,  no  two  individii^ls  being  exactly 
MvidTd.        ''''''"'      ''''  '""''^"'^  ^'^''''''   ^^''  ''^^^  ^^^  left  wings  of  the  same 


SUBPHYLUM  III 


INSECTA 


803 


Illustrations  of  the  tegiiiina  of  typical  Paleozoic  cockroaches  are  showii  in 
Figs.  1547  and  1548.  Aniong  North  American  examples  may  be  mentioned 
Adelohlafta  (Fig.  1549)  and  Äsemoblatta  (Fig.  1547)  Hand- 
lirscli,  botli  froni  the  Goal  Measnres  of  Illinois  ;  Phylohlatta 
and  Bradyblatta  Handlirsch,  from  the  Perinian  of  West 
Virginia  ;  Etoblattina  and  Spiloblattina  Scudder,  from  the 
Carboniferous  and  Permian  respectively. 

Order  12.    MANTOIDEA  Handlirsch. 

(Soothsayers  or  Praying  Insects). 


Head  exserted  but  deßexed,  not  covered  by  the  j^fothorax, 

which   is  elonyate  and  variously  formed,  but  never  disk-lihe. 

Mouth  parts  and  antennae  as  in  the  Blattoidea.     First  jpair 

of   legs   largely  developed,  raptorial,   the  coxae    elongate    and 

free;  second  and  third  pair  of  legs  simple  and  similar ;  the 

tarsi  five-jointedj  without  a  päd  between  the  claws ;  a  pair  of 

jointed  cerci  near  the   extremity  of  the  body.      Tegmina    less 

highly  specialised  than   in   the   Blattoidea,   subcosta   well   de-  pio.  1549. 

veloped,  anal  area  not  so  distinct.  Adeloblatta  columbiana 

(Scud.).  Goal  Measures ;  Mazon 
The   earliest    members    of   this   Order    are    the    extinct   Creek,    Illinois,      ^k    (after 

Palaeomantidae  from  the  Upper  Permian  of  Russia,    Higher 

types,  such  as  tlie  extinct  Haglidae  and  Geinitziidae,  appear  in  the  Lower  and  Upper 

Lias  respectively,  of  England  and  Germany.      The  latter  family  contains  the  single 

genus  Geinitzia  Handlirsch  (Fig.  1550),  represented  by  three 

species.      Comparatively  few  Tertiary  forms  are  known,  but 

in  the  modern  fauna  the  Mantidae  are  an  extensive  family, 

showing  extreme  variety   in   the  shape  of   the    body,   and 

characterised  by  the  very  remarkable  front  legs. 


CUy 


Fig.  1550. 


Geinitzia  schlieffeni  (Gein.).     Upper  Lias  ;  Dobbertin  in 
Mecklenburg.     5/2  (after  Handlirsch). 


Fig.  1551. 

Parotermes  inslgnis  Scudder 
Miocene  lake  beds ;  Florissant, 
Colorado,     -^/i. 


Order  13.     ISOPTBRA  BruUö.     (Termites  or  White  Ants). 

Social  terrestrial  Insects.  Head  not  concealed,  ivith  orthopteroid  mouth  parts,  and 
simple  antennae  consisting  of  from  nine  to  thirty-one  joints.  Wing  pairs  elongate  and 
similar,  anal  area  reduced,  and,  owing  to  a  sutiire  nmr  the  base  of  the  wings,  the 
'latter  are  deciduous.  Legs  similar,  the  body  terminated  by  a  pair  of  short  cerci, 
ovipositor  concealed.  JFingless  individuals  {worJcers,  or  sexually  reduced  males  and 
females)  are  polymorphous. 

True  Termites  or  White  Ants  appear  first  in  the  Eocene,  and  are  represented  in 
Tertiary  formations  by  about  forty  species.     In  the  modern  fauna  upwards  of  350 


804 


ARTHROPODA 


PHYLUM  VII 


species  are  known.     Parotermes  Scudder  (Fig.  1551) ;  Eutermes  Heer ;  and  Hodotermes 
Hagen  occur  in  the  Miocene  lake  beds  of  Florissant,  Colorado. 


Order  14. 


CORRODBNTIA  Burmeister  ^  (Copeognatha  Enderlein). 
(Book  Lice). 


Minute  terrestrial  Inseds  with  specialised  orthopteroid  mouth  parts,  filiform  or  hair- 

like  antennae,  and  two  pairs  of  wiequal  memhranous  wings  which  are  capaUe  of  heing 

folded  bachvard,  loüh  reduced  cross-veins.     Hind  wings  smaller, 

\  /    without  folded    anal   lohe;    neuration    highly    specialised.      Legs 

homonomous,  with  two-  or  three-jointed  tarsi.     Prothorax  small ; 

cerci  reduced,  ovipositor  not  prominent. 


A  number  of  species  belonging  in  part  to  extinct  and  in 
part  to  still  living  genera  is  known  from  Baltic  amber  (Lower 
Oligocene  of  East  Prussia),  and  from  Sicilian  amber  of  Upper 
Miocene  age.  A  very  remarkable  form  with  hard,  cbitinous 
wings,  and  interesting  from  a  phylogenetic  standpoint,  is 
Sphaeropsocus  Hagen  (Fig.  1552),  preserved  in  Baltic  amber. 

The  fifteenth  order  Mallophaga  Nitsche,  including  parasitic 
Bird  Lice  or  Biting  Lice,  witli  reduced  mouth  parts,  and  the 
sixteenth  order  Siphunculata  Meinert  ( =  Änoplura  Enderlein),  which  is  allied  to  the 
Mallophaga  but  has  suctorial  mouth  parts,  comprise  modern  ectoparasitical  Insects, 
and  are  not  known  to  be  represented  in  the  fossil  state. 


Fio.  1552. 

Spkaeropsocxis  kuenovii 
Hagen. '  Oligocene  amber ; 
East  Prussia.  i^/^  (after 
Hagen). 


Order  17.     COLEOPTERA  Linnaeus.     (Beetles). 

Terrestrial  or  aquatic  Insects  with  orthopteroid  hiting  mouth  parts  and  generally 
multiarticulate  antennae.  Four  wings  are  present ;  the  upper  pair  shell-lihe  in  con- 
sistency,  and  forming  cases  (elytra)  which  meet 
together  along  the  median  dorsal  line,  so  as  to 
sheathe  completely  the  delicate  memhranous  hind 
pair.  Legs  generally  homonomous  or  the  third 
pair  modified  for  swimming  or  leaping.  Ahdo- 
men  sessile,  without  cerci  or  prominent  ovipositor  '; 
the  number  of  visible  Segments  more  or  less  re- 
duced. 


Over  350  species  of  rather  primitive  Cole- 
optera  have  been  found  in  Mesozoic  strata,  the 
largest  number  being  from  the  Upper  Jura. 
The  majority  of  these  cannot  be  positively 
assigned  to  Recent  families,  although  it  is 
certain  that  many  of  these  were  represented  as 
early  as   the    Mesozoic.      On    the    other   hand,  Fio.  1553. 

most  of  the  Tertiary  Coleoptera  belong  to  exist-      ^'«wedo«,  homi  Handl.     Lithographie  Stone 

ing  families,  and  comprise  nearly  2300  species.  ^^^^'' '^'"''•'^ '  ^^^'^^^^-^  %  (after  Handiirsch.) 
This,  however,  is  a  small  number  in  comparison  to  something  like  200,000  described 
species  of  Recent  beetles. 

The  principal  families  which  are  represented  in  the  fossil  state  are  the  Carabidae, 
to  which  belongs  the  cursorial  beetle   Tauredon   Handl.   (Fig.    1553);    Elateridae ; 
Buprestidae;  Dytiscidae,  ete.     The  Strepsiptera  of  Kirby  may  be  considered  as  a 
1  £nderlein,  G.,  Die  fossilen  Copeoguatheu  und  ihre  Phylogenie.     Palaeontogr.,  1911.  vol.  Iviii. 


SüBPHYLUM  III 


INSECTA 


805 


liighly  specialised  parasitical  group  of  Coleoptera. 

the   Rhyncliopliora  is   represented   in  the  Cretaceous  of   Greenland    by  tvvo  genera 

{Archiorhynchus  Heer  and  GurcuUopsis  HandL),  and  much  more  abundantly  in  the 


Ku;.  1/ 


Fin.  1555. 


Cyphon    vetustus 
Giebel.    Purbeck ; 
Vale   of  Wardonr, 
England.  6/^  (after     England 
Brodie).  Brodle). 


Cerylonopsis  striata 
(Brodie).  Purbeck ; 
Vale     of     Wardour, 

*^/i  (after     Scudder.     Miocene  lake  beds  ; 
Florissant,  Colorado.    5/i. 


Fig.  1556. 
Paltorhynchus        redirostris 


Fio.  1557. 

Apion  refrenatum  Scudder. 
Miocene  lake  beds ;  Floris- 
sant, Colorado.     i2/j. 


freshwater  Miocene  of  Florissant,  Colorado.  The  divisions  Heteromera,  Phytophaga, 
Lamellicornia,  Serricornia,  Clavicornia  and  Adephaga  are  also  fairly  well  represented 
at  the  latter  locality.  Two  English  and  two  American  species  are  shown  in  Figs. 
1554-1557. 


Order  18.     HYMENOPTERA  Linnaeus.^     (Ants,  Bees,  Wasps,  etc.). 


Terrestrial  Insects  ivith  a  free  head  having  ivell-developed  mandihles ;  the  first  and 
second  maxillae  are  often  elongated,  and  form  in  the  higher  groups  a  tubulär  proboscis 
adapted  for  sucJcing.  Antennae  generally  long  and  multiarticulate.  Thorax  and  first 
abdominal  Segments  fused,  the  rest  of  the  abdomen  generally  well  separated  by  a  con- 
striction.     Legs  usually  homonomous,  with  five-^ointed  tarsi ;  cerci.not  distinct ;  genital 


Atocus    defessus    Scudder.      Miocene    lake 
beds  ;  Florissant,  Colorado.     2/^. 


Fig.  1559 


Pseudosirex  schroeteri  Genn.  Litho- 
graphie Stone ;  Soienhofen,  Bavaria.  i/i 
(after  Oppenheim). 


appendages  of  the  female  forming  either  a  more  or  less  pronounced  terebra  or  a  sting. 
Four  wings  of  membranous  consistency  and  a  reduced  number  of  veins ;  the  front  pair 
larger  than  the  hind^  which  are  always  smaller  and  rarely  fold  up  in  repose.  TFingless 
forms  frequent. 

The  earliest  members  of  this  order  are  of  Jiirassic  age,  and  it  is  probable  that  some 


1  Mai/r,  G.,  Die  Ameisen  des  baltisclien  Bernsteins, 
berg,  1868. — Idem,  Studien  über  die  Radoboj-Formiciden. 
vol.  xvii.  —  Wheeler,  W.  M.,  Ants.     New  York,  1910. 


Schriften  der  phys.-ökon.  Ges.  Königs- 
Jahrb.  geol.  Reiclisaust.  Wien,  1868, 


806 


ARTHROPODA 


PHYLUM  VII 


primitive  types  of  tlie  suborder  Symphyta  were  already  in  existence  during  the  Mesozoic, 
although  the  most  primitive  saw-fiies  (Lydidae  or  Pamphilidae)  are  not  known  from 
rocks  older  than  tlie  Tertiary.  About  2900  Recent  species  of  saw-flies  are  known, 
several  are  preserved  in  Baltic  amber,  and  fifty  or  more  have  been  described  from 
Tertiary  strata  in  Europe  and  North  America.  Of  this  number  thirty-three  occur 
exclusively  in  the  Miocene  lake  beds  of  Florissant.  Here  belong 
the  genera  Dineura  and  Taxonus  Dahlb.;  Tenthredo  Linn.;  and 
Atocus  Scudder  (Fig.  1558).  Agroup  of  more  highly  specialised 
Siricid-like  Insects,  constituting  the  extinct  family  Pseudo- 
siricidae  {Pseudosirex  Weyenb.)  (Fig.  1559)  is  rather  abundant  in 
Jurassic  formations  of  Europe,  being  accompanied  by  forerimners 
of  the  next  higher  suborder,  Apocrita.  A  great  expansion  of 
the  Order  took  place  during  tlie  Cretaceous,  contemporaneously 
with  the  rise  of  Angiosperms. 

Nearly  all  of  the  principal  modern  families  are  represented 
in  the  Mid-Tertiary  formations,  as  for  instance  true  saw-flies  of 
the  family  Tenthredinidae  ;  Siricidae ;  various  subfamilies  of  the 
parasitic  Ichneumonidae  ;  small  Cynipidae  or  gall-flies;  Sphecidae; 
May^JL^weroiigo^enel  Vespidae  or  wasps ;  Formicidae  or  ants  (Fig.  1560);  and  Apidae 
Baitic  amber.  2/j  (after  Qp  j^g^g  Ants  are  exceedingly  abundant  in  the  Miocene  lake 
beds  of  Florissant,  Colorado,  thousands  of  individuals  having  been 
obtained,  and  true  wasps  and  bees  are  also  present  in  large  numbers.  About 
5000  species  and  sub-species  of  ants  belonging  to  the  modern  fauna  have  been 
described,  as  compared  with  about  only  300  Tertiary  species. 


Fio.  15(30. 
Prionomynnex  longipes 


t  Order  19.     HADENTOMOIDBA  Handlirsch. 

This  Order,  comprising  a  single  family  and  genus,  is  evidently  derived  from  the 
Palaeodictyoptera,  and  shows  specialisation  in  the  reduced  venation  of  the  homonomous 
wings.^  The  small  Carboniferous  genus  Hadentomum  Handl.  (Fig.  1561)  is  perhaps 
transitional  to  the  next  following  order. 


Order  20.     EMBIOIDEA  Kusnezow 

(Oligoneura  Börner). 

Terrestnal  Insects  with  prognathous  orthopteroid 
mouth  parts,  homonomous  free  thoracic  Segments, 
apterous  or  with  homonomous  wings  showing  re- 
duced venation.  Antennae  multiarticulate ;  cerci 
present ;  first  pair  of  legs  with  a  spinning  apparatus. 

Modern  Embiidae  are  one  of  the  smallest 
famüies  of  Insects,  not  more  than  sixty  species 
being  known  from  all  parts  of  the  world,  and 
the  group  being  an  obscure  one.  They  are  small 
and  leeble  Insects,  and,  as  indicated  by  their 
Wide  distribution,  are  to  be  looked  upon  as  the 
mnnants  of  a  once  flourishing  stock.  A  few 
fossil  remains  have  been  found  in  Baltic  amber  and 
in  the  Miocene  lake  beds  of  Florissant,  Colorado 


Fl(i.  15H1. 

Hadentomum  aviericannm  Handl,     Goal 
Measnres  ;  Illinois,    a/g  (after  Handlirsch). 


SüBPHYLUM  III 


INSECTA 


807 


t  Order  21.     SYPHAROPTEROIDBA  Handlirsch. 

Body  slender,  of  small  size,  with  homonomous  segments  and  two  pairs  of  homonomous 
lüings  in  ivhüh  the  medial  and  cuhital  veins  are  greatly  reduced. 

Tliis  Order,  erected  to  contain  the  single  geniis  Sypharoptera  Handl.  (Fig.  1562), 


Fig.  1562. 
Sypharoptera  pneuma  Handl.     Goal  Mcasures  ;  Mazon  Creek,  Illinois,     -i/i  (after  Handlirsch). 

is  probably  to  be  regarded  as  a  bigbly  specialised  lateral  aberrant  ofFshoot  of  the 
Palaeodictyoptera.      It  is  confined  to  the  Upper  Carbon iferous. 


t  Order  22.     HAPALOPTEROIDBA  Handlirsch. 

Like  the  last,  this  order   is   probably  a  specialised  derivative  from  the  Palaeo- 
dictyoptera, and  appears  to  be  related  to  primitive  types  of  the  next  succeeding  order. 


'  cu' 


Fi(i.  15(53. 
Hapaloptera  gracUis  Handl.     Goal  Jleasures  ;  Tremont,  Penna.     •'»/i  (after  Handlirsch). 


In   the   Carboniferoiis  geniis  Hapaloptera   Handl.  (Fig.   1563),  the  wings  have   the 
media  and  cul)itus  reduced,  and  the  sector  radii  well  developed. 


808 


ARTHROPODA 


PHYLUM  VII 


Order  23.     PBRLARIA  Handlirsch  {Flecoptera  Burmeister). 

Amphibioiis  Inseds  with  procjnathous  ortJiopteroid  mouth  parts  and  long  multi- 
articulate  antennae.  Body  segments  very  nearly  Jwmonomous,  legs  fairly  similar,  and 
wings  with  a  rather  specialised  venation,  generally  showing 
a  few  cross-veins.  Hind  wings  often  with  a  conspicuons 
foldedanal  lohe;  cerci  usually  well-developed ;  tarsi  three- 
jointed ;  fem,ales  without  a  prominent  terehra. 

Fi.i,  1564.  From  tlie    Permian   of    Russia  and  North  America" 

l^idra  gracilis  Pictet.  Lower  are  known  a  number  of  Insect  remains  wliicli  appear  to 
PiSr^'^''^*'''^'"^''"  '^^  ^'''^^''"  l^eloiig  to  this  Order,  but  whose  precise  relations  are 
difficult  to  determine.  A  few  undoubted  representatives 
of  tlie  Order,  such  as  Mesonemura,  Mesoleuctra  and  Platyperla  Brauer,  occur  in  the 
Middle  Jura  of  Siberia,  and  several  genera,  including  Perla  Geoft'r.,  and  Leuctra 
Steph.  (Fig.  1564)  are  preserved  in  Baltic  amber. 


t  Order  24.     PROTEPHBMEROIDEA  Handlirsch. 

Ämphibious  Inseds  of  Palaeodidyopteran  asped.  Wings  homonomous,  with  a  very 
primitive  venation  and  numerous  cross-veins,  hut  also  showing  intercalary  veins  extending 
longitudinally.  Thorax  and  ahdomen  with  very 
nearly  homonomous  segments;  legs  similar;  cerci 
long. 

Here  is  placed  the  solitary  genus  Triplosoha 
Handl.  {  =  Blanchardia  Brongn.)  (Fig.  1565)  from 
the  Upper  Goal  Measures  (Stephanian)  of  Com- 
mentry,  France.  It  is  regarded  as  a  connecting 
link  between  the  Palaeodictyoptera  and  true 
Ephemeridae  or  may-flies  belonging  to  the  next 
Order. 

Order  25.     PLECTOPTERA  Packard 

{Agnatha  auct.).     (May-flies). 

Delicate  ämphibious  Insects  with  atrophied  ortho- 
pteroid  mouth  parts,  short  antennae,  and  four  membranous  wings  having  both  intercalary 
and  cross-veining ;  the  hinder  pair  in  all  Recent  and  many  fossil 
species  more  or  less  reduced  and  sometimes  wanting.  Antennae 
Short,  with  two  basal  joints  and  an  apical  needle-like  segment 
Ocular  Organs  large,  often  divided.  Prothorax  small,  legs  slender, 
the  first  pair  elongated,  antenniform ;  tarsi  more  or  less  reduced ; 
cerci  slender,  very  elongate ;  last  segment  often  filiform.  Larvae 
loith  respiratory  abdominal  legs. 

This  Order  is  well  represented  in  the  Permian,  Jurassic, 
and  Tertiary  deposits  of  Europe  and  North  America.  The 
older  forms  differ  from  existing  Ephemerids  in  having  the  hind 
wings  equal  in  size  to  the  front  pair,  and  in  having  more  com- 
(Pictot)  fower"or""  }^^^^*^^  /^'^^a^ion.  Later  and  more  highly  specialised  forms 
cene -Baltic  amber. '^3°;  [^^^^  leduced  venation.  Nearly  300  species  of  may-flies  are 
known  in  the  modern  fauna,  but  these  probably  represent,  as 


Fig.  1565. 

Triplosoha  pulchella  (Brongn.).  Stephan- 
ian ;  Commentry,  France.  Vi  (after 
Brongniart). 


Fio,  1566. 
Cronicus    anomalus 


(after  Pictet). 


SUBPHYLUM  III 


INSECTA 


809 


Scudder  suggested,  the  lingering  fragments  of  an  expiring  groiip.  The  genera 
Cronicus  Eaton  (Fig.  1566) ;  Palingenia  Burm. ;  Baetis  Leach  ;  and  Ephemer a  Linn. 
occur  in  Baltic  aniber,  and  the  last-nained  is  found  also  in  the  Miocene  lake  beds  of 
Florissant,  Colorado. 


t  Order  26.     PROTODONATA  Brongniart. 

Mostly  very  large  Insects  ivith  large  eyes  and  heavy  jaws ;  segments  of  the  thorax 
unequal ;  legs  stout,  homonomous.      Wings  suhequal,  horizontally  expanded  and  with  a 


Meganeura  monyi  Brongn. 


Fig.  1567. 

Stephanian  (Upper  Productive  Goal  Measures) ;  Commentry  (Allier),  France. 
i/g  (after  Brongniart). 


finely  reticulated  venation ;  the  hinder  pair  somewhat  dilated  towards  the  hase,  without 
folds.  Nodus,  pterostigma,  wing  triangle,  quadrangle,  reduction  of  the  anal  vein,  and 
other  characteristic  wing  structures  of  the  true  Odonata  are  not  developed  in  this  order. 
Sector  radii  and  media  prohahly  not  crossed.     Abdomen  slender. 


This  group  is  of  traiisitional  character  between  the  Palaeodictyoptera  and  the  true 
Odonata  or  diagon-flies.  Its  geological  ränge  is  from  the  Goal  Measures  to  the  Trias, 
and  the  several  genera  belonging  to  it  are  grouped  under  the  families  Protagrionidae, 
Meganeuridae  and  Paralogidae.  In  all,  less  than  a  dozen  species  are  known,  only 
three  of  which  are  North  American.  These  last  are  referred  to  the  genera  Paralogus 
Scudder,  typified  by  F.  aeschnoides  from  the  Goal  Measures  of  Ehode  Island  ;  Palaeo- 
therates  Handlirsch,  from  the  corresponding  horizon  in  Pennsylvania ;  and  Tupus 
Sellards,  from  the  Permian  of  Kansas.  The  gigantic  Meganeura  Brongn.  (Fig.  1567), 
from  the  Upper  Goal  Measures  (Stephanian)  of  Gommentry,  France,  measured  over 
75  cm.  across  the  extended  wings. 


810 


ARTHROPODA 


PHYLUM  VII 


are  elonyate, 

reticulated,  with  a  nodus,  pterostigma, 


Order  27.     ODONATA  Fabricius.i     (Dragon-flies). 

te  Insects  with  very  mohile  head  and  large  eyes,  highly  specialised  orthopteroid 

mouth  parte  and  small,  inconspicuous   antennae   terminating   in  a    hnstle        Thorax 

Z  y  ^eciaUsed;  legs  Mar,  all  placed  more  anteriorly  than  the  ^v^ngs.      The  u.ngs 

equal  or  suhequal  in  size  and   similar  m    texture,   membranous,  finely 

more   or   less  developed  triangulär  areas,  and 

especially    characterised     hy 

y      ^  ^     r  the  Crossing  of  the  anterior 

hranches  of  the  medial  vein 
hy  the  radial  sector.  Abdo- 
men slender  and  elongate, 
consisting  of  ten  segments 
and  a  pair  of  terminal 
caliper-like  processes  (cerci) ; 
females  sometimes  with  a 
terebra.  The  earlier  stages 
of  life  are  aquatic ;  the 
mouth  of  the  nymph  develops 
a  peculiar  structure  called 
the  "  masJc." 

True  Odonata  appear 
first  in  the  Lower  Lias,  and 
are  present  throughout  the 
Mesozoic  and  Tertiary. 
Most  of  the  Jurassic  types 
belong  to  the  siiborder 
Anisozygoptera,  which  is 
represented  in  the  modern 
fauna  by  but  a  single 
species.  The  more  advanced 
suborders,  Zygoptera  and 
Anisoptera,  became  domi- 
nant durin g   the  Tertiary, 


o 

Fia.  1568. 
Vl'arsophM)ia  eximia   Hagen.      Lithographie    Stone    (Kimmeridgian) ; 
Eichstädt,  Bavaria.    An  Upper  Jurassic  dragon-fly  with  long,  forwardly 
directed  legs.    5/;j  (after  Handlirsch). 


and  comprise  at  the  present  day  iipwards  of  1000  and  1300  species  respectively. 

In  the  Anisozygoptera  the  wings  are  subequal  and  the  nodal  region  resembles  that 
of  the  next  succeeding  suborder,  but  triangles  are  not  formed  by  the  cubitus  and 
cross-veins.  Here  belong  the  extinct  families  Diasatommidae  ;  Heterophlebiidae  ; 
Tarsophlebiidae  (typified  by  the  genus  Tarsophlebia  Hagen,  Fig.  1568);  Steno- 
phlebiidae  and  Isophlebiidae. 

In  the  Anisoptera  the  hind  wings  are  considerably  broader  than  the  front  pair, 
the  nodal  region  is  generally  situated  in  the  middle  of  the  costal  margin  and  the 
triangle  formed  by  the  cubitus  and  two  cross-veins  is  well  developed.  A  single 
species  belonging  to  the  genus  Gomphoides  Selys  is  known  from  the  English  Lias,  and 
a  number  of  allied  genera,  such  as  Nannogomphus  and  Mesuropetala  Handl.  ; 
Protolindenia  and  Gymatophlebia  (Fig.  1569)  Deichmüller;  Aeschnidium  Westwood, 
etc.,  occur  in  the  Upper  Jura.  In  Tertiary  strata  the  families  Gomphidae,  Aeschnidae 
aud  Libellulidae  are  represented  by  about  sixty  species.  As  an  example  of  Tertiary 
Anisoptera  luay  be  mentioned  Stenogomphus  carletoni  Scudder,  from  the  Eocene  strata 
of  Roan  Mountain,  Colorado. 

^  Kirby,  W.  F.,  Syiionymic  Catalogxie  of  Neuroptera  Odonata,  with  an  appendix  of  fossil 
species.  London,  lS90.—ÄfuttkoiosH,  R.  A.,  Catalogne  of  the  Odonata  of  North  America.  Bull. 
Puhlic  Museum  of  Milvvaukee,  1910,  vol.  i. 


SUBPHYLÜM  III 


INSECTA 


811 


In  tlie  suborder  Zygoptera  tlie  wings  are  eqiial,  no  triangle  is  formed  by  the 
cubitus  and  cross-veins,  and  tlie  nodal  region  is  situated  very  near  tlie  base  of  the 
wings.  Half  a  dozen  species  are  known  from  tlie  Upper  Jura,  and  a  considerably 
larger  number,  mostly  belonging  to  the  faiiüly  Agrionidae,  occur  in  the  Oligocene  and 
Miocene  of  Europe  and  North  America.  Dysagrion  Scndder  is  represented  by  a  few 
species  in  the  Green  River  Eocene  of  Wyoming,  and  several  species  closely  related 


Fig.  1569. 

Cymaiophlebia  longialata  (Germar), 
Lithographie  Stone ;  yolenhofen, 
Bavaria.     ^/s- 

Argia  aliena  (Scudder).     Miocene  lake  beds  ;  Florissant, 
Colorado,     '^/i- 

to  living  forms  are  known  from  the  Miocene  lake  beds  of  Florissant,  Colorado. 
Here  also  occurs  Ärgia  aliena  (Send.)  (Fig.  1570),  together  with  representatives  of 
several  related  forms,  such  as  Melanagrion  Cock. ;  Lithagrion  Send. ;  and  Hesperagrion 
Calvert.  The  most  interesting  dragon-fly  from  this  locality,  however,  is  Phenacolestes 
Cockerell,  which  has  been  raade  the  subject  of  special  investigation  by  R  P.  Calvert 
{Proc.  Acad.  Nat.  Sei.  Philad.,  May  1913). 

Order  28.     MEGALOPTBRA  Latreille.     (Alder-flies). 

Head  with  prognathous  orthopteroid  mouth  parts  and  multiarticulate  antennae. 
Four  membranous  wings  of  moderate  size,  meeting  in  repose  over  the  hack  at  an 
angle ;  the  hinder  pair  slightly  the  smaller ;  anal  area  plicate.  Venation  of  a  some- 
what  archaic  type,  the  nervures  and  transverse  veinlets  heing  moderately  numerous, 
and  forming  irregularly  disposed  cells.  Segments  of  the  thorax  nearly  equal,  legs 
homo7iomous,  with  five  -  jointed  tarsi ;  cerci  usually 
reduced,  ovipositor  not  prominent.  Larvae  of  aquatic 
hahits,  possessed  of  hranchiae  and  legs,  hut  no  spiracles, 
and  with  mandibles  formed  for  hiting,  armed  with  strong 
teeth. 

Fi(».  1Ö71. 

This  group  has  a  long  geological  history,  extending  (,^„„^.,^,,  j^^^m  Pictet.  Lower 
from  the  Jjower  Trias  onward  to  the  present  day,  and  is  oligocene ;  Baltic  amber.  ■*/.!  (after 
probably  descended  from  Palaeodictyopteroid  ancestors.    ^^^^^^)- 

The  genera  Ghauliodites  Heer,  and  Triadosialis  Handlirsch  occur  in  the  Lower  Trias 
(Bunter)  of  Germauy,  and  an  undoubted  larval  form,  Mormolucoides  articulatiis 
Hitchcock,  is  not  uncommon  in  the  Upper  Trias  of  Turner's  Falls,  Massachusetts. 
In  this  latter  a  head,  or  thorax,  of  tliree  segments,  and  an  abdomen  of  nine  segmeiits 


812 


ARTHROPODA 


are  recognisable.     Chauliodes  Latreille  (Fig.  1571),  an  interesting  form, 
in  lialtic  ainber  of  Lower  Oligocene  age. 


PHYLUM  VII 


preserved 


Order  29.     RAPHIDIOIDEA  Handlirsch.     (Snake-flies). 

Terrestrial  Insects  with  prognathous  orthopteroid  mouth  parts  and  long,  multi- 
articulate  antennae.  Head  large,  ahdomen  slender,  prothorax  greatly  prolonged  and 
very  mobile.  Wings  similar,  memhranous,  of  nearly  equal  size ;  venation  more  highly 
specialised  than  in  the  Megaloptera,  with  a  prominent  pterostigma ;  anal  veins  forming 
several  irregulär  cells,  of  moderate  size,  and  never  fan-shaped  in  arrangement.  Legs 
similar,  with  five-jointed  tarsi ;  no  cerci ;  females  with  an  elongate  exserted  ovipositor. 
Larvae  of  terrestrial  hahits,  without  abdominal  legs  and  furnished  with  mouth  parts 
adapted  for  biting. 

Only  two  Recent  genera  are  known,  Eaphidia  Burm.,  and  Inocellia  Schneid., 
comprising  in  the  aggregate  about  forty  species.  The  former  of  these  occurs  fossil  in 
Baltic  amber  of  Lower  Oligocene  age,  and  both  genera  are  represented  in  the  Miocene 
lake  beds  of  Florissant,  Colorado,  by  a  few  species,  Megaraphidia  elegans  Cock.  also 
occurs  at  the  last-named  locality.  It  is  to  be  inferred,  however,  that  the  group  is 
of  pre-Tertiary  origin,  inasmuch  as  the  modern  genera  are  peculiar  to  the  Palearctic 
and  Nearctic  regions. 


Order  30.     NBUROPTBRA  Linnaeus.     (Lacewing-flies,  Ant-lions,  etc.). 

Usually  slender,  often  very  small  Insects  of  terrestrial  habits,  with  orthopteroid 
mouth  parts  and  generally  long  and  multiarticulate  antennae.  Wings  membranous, 
subequal  in  size,  with  much  reticidation,  and  longitudinal  veins  giving  off  numerous 
branches  towards  the  margin,  some  of  them  distally  forked  ;  anal  area  not  defined,  with 
few  irregulär  veins;  pterostigma  seldom  developed.  Legs  similar,  lüith  five-jointed 
tarsi,  front  pair  sometimes  raptorial ;  abdomen  without  cerci  or  terebra.  Larvae  either 
aquatic  and  provided  with  respiratory  abdominal  legs,  or  terrestrial ;  in  both  cases  with 
mandibles  and  maxillae  co-adapted  toform  spear-lihe  organs  that  are  suctorial  in  function. 

In  the  emended  sense  this  order  includes  only  a  limited  number  of  species,  of 
which  about  1300  are  Recent,  less  than  30  are  Cenozoic,  and  a  small  number  are 


Fio.  1572. 
Iirodromus    Handl. 


Prohn,.,:  _         ,  _ 

pobb(;rUu    in    M.'cklenbiirK 
Handlirsch) 


Upper    Lias ; 
Vi  (reconstructed  by 


Fig.  1573. 

Brongniartiella  inconditissima  Handl. 
Lithographie  Stone  ;  Solenhofen,  Bavaria. 
2/3  (after  Handlirsch). 


andT;rt.  Lw  t     ^  '  r':1  ^f""  Palaeodictyopteroid  ancestors.     The  oldest 
.»est  pnm>tive  fa.ndy,  that  of  the  Prohemerobiidae,  is  represented  in  the  Lias 


I 


SUBPHYLUM  III 


INSECTA 


813 


and  Upper  Jura  by  twenty-two  species,  some  of  which  attain  considerable  size.  The 
genera  Prohemerobius  (Fig.  1572)  and  Archegetes  Handl. ;  and  Brongniartiella  Meunier 
(Fig.  1573)  are  examples. 

Otlier  families  of  Neiiropterous  Insects  which  are  restricted  to  the  Mesozoic,  such 
as  the  Epigambridae,  Solenoptilidae,  Nymphitidae,  Kalligrammidae  and  Mesochryso- 
pidae,  show  a  certain  approximation  to  Tertiary  and  modern  forms.  Members  of  the 
now  flourishing  Osniylidae,  Sisyridae,  Nymphidae,  Hemerobiidae,  Coniopterygidae, 
Chrysopidae,  Nemopteridae  and  Myrmeleonidae  have  been  recorded  from  Tertiary 
rocks.     The  genera  Osmylus  Latr.  ;   Osmy- 

lidia    Cockerell ;     Bothromicromus,    Tribo-     ^,^^^^^^__  /  \/\ 

chrysa  and  Palaeochrysa  Scudder  are  <^^^^^^^^^s^M^^ 
represented  in  the  North  American  Mio- 
cene.  The  last-named  genus  is  represented 
by  four  species  at  the  Florissant  locality, 
and  Tribochrysa  by  one.  A  single  species 
each  of  Polystoechotes  Burm.,  and  Halter 
Eambur,  has  also  been  described  from  the 
same  locality. 

t  Order  31.     MBGASBCOPTERA 
Brongniart. 

Insects  lüith  slender  body,  the  segments 
of  which  are  very  siviilar,  long  antennae 
and  cerci,  and  homonomous  legs.  Wing 
pairs  equal,  horizontally  expanded,  venation 
specialised  in  that  there  is  a  reduced  numher 
of  branches  and  cross-veins. 

This  is  an  exclusively  Paleozoic  group, 

derived  from  the   Palaeodictyoptera,  and 

probably  the  progenitor  of  the  next  suc-  Fig.  1574. 

ceeding  order.  Here  belong  the  families  Mischoptera  woodtmrdi  Brongn.  Stephanian  (Upper 
-rv-      1,  +     -1  /-^        ;i    1    'j-i  n^^      Goal    Measures) ;    Commentry,    France.     Ocelli   and 

Diaphonopteridae,    Corydaloididae,    Cam-   tarsi  restored.    v,  (after  Handiirsch). 

pylopteridae,  Mischopteridae  (typified  by 

the  genus  Mischoptera  Brongn.)  (Fig.  1574),  Raphidiopsidae  and  Prochoropteridae. 


Order  32.     PANORPATAB  Brauer  (Mecaptera  auct.).     (Scorpion-flies). 

Terrestrial  Insects  with  orthopteroid  mouth  parts  and  long,  multiarticulate  antennae. 
Prothorax  smaller  than  the  remaining  segments;  legs  similar^  lüith  five-jointed  tarsi ; 

abdomen  slender,  with  short    cerci   and 

r „„ ^^^ .r== :       large    genital    appendages  in   the  male. 

Wings  equal,  membranous,  without  en- 
larged    anal   lobe,    and   with   a   limited 
number  of  secondary  branches  and  cross- 
veins. 
CH 


This  Order,  which  is  now  in  a  state 
of  decline,  is  abundantly  represented 
in  the  Lias  and  Upper  Jura  of  Europe. 
Most  of  the  fossil  species  belong  to  the 
family  Orthophlebiidae,  of  which  the  genera  Orthophlebia  Westw.,  and  Neorthophlebia 
Handl.     (Fig.   1575)  are  examples.     True  Panorpidae  and   Bittacidae  occur  in  the 


Fia.  1575. 

Neorthophlebia  maculipennis  Handl.  Upper  Lias  ;  Dob- 
bertin  in  Mecklenburg.    5/j  (after  Handlirsch). 


814 


ARTHßOPODA 


PHi'LUM  VII 


Tertiary  of  Europe  and  North  America.  Representatives  of  tlie  families  Meropidae 
and  t  Eobanksiidae,  the  latter  typified  by  Eohanksia  Cockerell,  are  also  known  from 
the  Florissant  lake  beds.     About  100  Recent  species  of  Scorpion-flies  are  known. 

Order  33.     TRICHOPTERA  Kirby  {Phryganoidea  Stephens). 

Moderate-sized,  water-frequenting  Inseds  with  long,  multiarticulate  antennae  and 
reduced  or  obsolete  mandibles,  but  ivell-developed  maxülae.  Wings  memhranous,  unequal, 
more  or  less  clothed  with  hair,  nervures  dividing  at  very  acute  angles  ;  the  front  pair 
ivith  longüudinal  veins  moderately  branched,  very  few  cross-veins,  specialised  anal  area, 

and  often  a  pterostigma  ;  the  hind  pair  generally 
with  an  enlarged  and  plicated  anal  lobe.  Pro- 
thorax small,  legs  similar,  with  five-jointed  tarsi 
and  prominent  spiirs ;  cerci  reduced,  terebra 
loanting.  Larvae  aquatic,  with  well  -  developed 
mandibles,  and  as  a  rule  providing  themselves  with 
cases  or  tubes  formed  of  extraneous  matter. 

Fig.  1576.  Sonie   half  -  dozen   genera   coniprising    fifteen 

Necrotaulius  inte-nnedhis  Handi.    Upper   gpecies  of  primitive  Caddis-flies  are  known  from 

Lias;  Dobbeitin  in  Mecklenburg,    »/i  (alter      \  .        ^  -       r    ^i  v  i  •  ..       ^v 

Handlirsch).  Mesozoic  rocks,  most  Ol   them   belongmg  to   the 

extinct  family  Necrotauliidae.  Necrotaulius 
Handl.  (Fig.  1576);  and  Trichopteridium  Geinitz  are  examples  from  the  Upper  Lias 
of  Germany.  About  1400  Recent  and  200  Tertiary  species  have  been  recorded, 
of  which  24  occur  in  the  Miocene  lake  beds  of  Florissant,  Colorado.  At  this 
locality  remains  in  the  imago  State  are  extremely  abundant,  and  many  such  remains 
have  been  found  in  Europe.  On  the  other  band,  the  so-called  indusial  limestone 
of  Auvergne,  which  is  from  two  to  three  metres  thick  over  a  wide  area,  is  largely 
composed  of  the  cases  of  Phryganoid  larvae.  Similar  masses  of  tubes  occur  also  in 
the  Green  River  Eocene  of  Wyoming. 


Order  34.     LBPIDOPTERA  Linnaeus.     (Butterflies  and  Moths). 

Terrestrial  Insects  with  suctorial  mouth  parts,  in  which  the  mandibles  are  ahmst 
invariably  reduced  and  the  first  maxillae  are  either  small  -or,  in  higher  forms,  frolonged 
in  a  spirally  coiled  proboscis ;  antennae  multi- 
articulate  and  of  various  shapes.  Fore  and  hind 
itnngs  unequal  in  size,  membranous  and  densely 
covered  with  scales  ;  the  hind  -pair  shorter  and 
usually  without  enlarged  anal  area.  Longitu- 
dinal  veins  giving  off  but  a  limited  number  of 
straight  branches,  and  with  very  few  cross-veins. 


Fid.  1577. 

J ■knvj, ad', edles  dornest  Öppenli.     Middle  Jura 

öiberia.    -^/s  (after  Oppenheim). 


Fig. 

Eocicada  lameeri  Handl.  Lithographie 
8tone  (Upper  Jura)  ;  öoleuhofen,  Bavaria. 
Au  Upper  Jurassic  Lepidopterid,  the  antennae 
and  ocelli  restored.  .  4/y  (after  Handlirseh).    -  - 


SUBPHYLUM   III 


INSECTA 


15 


Thorax  much  abbreviated,  legs  similar,  ivith  spiirs ;  no  cerci  or  terebra. 
mandibles,  thoracic  and  abdominal  legs. 


Larvae  with 


The  earliest  uiidoubted  traces  of  Lepidoptera  aie  fouiid  in  Jurassic  strata  of 
England,  Spain,  Bavaria  and  Siberia,  and  comprise  a  nnniber  of  genera  belonging  to 
tlie  faniily  Palaeontinidae.  Phragmatoe- 
cites  (Fig.  1577),  Eocicada  (Fig.  1578),  and 
Prolystra  Oppenheim  are  exaniples,  these 
forms  being  somewhat  distantly  allied  to 
the  non-suctorial  Limacodidäe  of  our  own 
day.  Several  modern  families  make  their 
appearance  in  the  Tertiary,  bnt  are  repre- 
sented  by  relatively  few  species.  The 
total  nnmber  of  Tertiary  species  is  not 
over  85,  as  against  some  60,000  Eecent 
butterflies  and  nioths.  Among  North 
American  exaniples  may  be  mentioned  the 
foUowing  from  the  Miocene  lake  beds  of 
Florissant,  Colorado,  all  described  by 
Scudder  :  Prodryas  persephone  (Fig.  1579), 
Barbarothea  ßorissanti  (Fig.  1580),  Jwpiteria  charon,  Lithodryas  styx,  Nymphalites 
obscurus,  Prolibythea  vagabunda,  Psecadia  mortuella,  and  Stolopsyche  libytheoides. 
From  the  same  locality  Gockerell  has  described  Ghlorippe  wilmattae  and  some  other 
species,  including  a  well-preserved  larval  form  known  as  Phylledestes  vorax. 


Fig.  1579. 

Prodryas  persephone  Scudder.     Miocene  lake  beds  ; 
Florissant,  Colorado,     i/j  (after  Scudder). 


Order  35.     DIPTERA  Linnaeus.     (Flies). 

Terrestrial  or  amphibious  Insects  with  highly  specialised  suctorial  mouth  parts. 
Antennae  either  long  and  multiarticulate,  or  consisting  of  a  limited  number  of  similar 
or  dissimilar  joints.     Only  the  fore  wings  are  prominent ;  these  are  usually  well  developed, 

membranous,  highly  specialised,  narroiv,  with 

/  ^  few    cross  -  veins,     and     longitudinal    veins 

1^^  sparingly    branched.       Hind    wings    always 

^^^^Mp^^^^^E  reduced   to   clubbed  ßlaments,    the   so-called 


Fig.  1580. 

Bdi-barothea  florismnti  Scudder. 
Miocene  lake  beds;  Florissant,  Colo- 
rado.    Vi  (after  Scudder). 


oTCU 


Fio.  1581. 

Architipula  seehachiana  Handl.  Upper 
Lias  ;  Dobbertin  in  Mecklenburg.  6/j  (after 
Ilandlirsch). 


"  halteres."     Thorax  much  abbreviated,  legs  generally  homonomous,  with  five-jointed  tarsi ; 
abdomen  without  terebra  or  visible  cerci. 

Upwards  of  44,000  Recent  and  1550  Tertiary  species  are  known,  125  of  the 
latter  being  North  American.  The  earliest  Flies  are  found  in  the  Upper  Lias,  and 
comprise  about  30  species,  nearly  all  of  which  belong  to  the  suborder  Orthorrapha 
of  Brauer.  They  are  grouped  in  the  following  named  families :  Protorhyphidae, 
Mycetophylidae,  Bibionidae,  Psychodidae,  Eoptychopteridae,  Architipulidae  (typified 
by  the  genus  Architipula  Handl.)  (Fig.  1581),  Tipulidae  and  RhypÖidae.  .     In  the 


816 


ARTHROPODA 


PHYLÜM  VII 


Tertiarv  of  Nortli  America  tlie  same  suborder  is  abundantly  represented,  especially 
in  tho  Miocene  lakc  beds  of  Colorado,  wliere  thousands  of  individuals  and  hundreds 
of  species  have  been  found.     The  suborder  Cyclorrapha  is  likewise  well  represented 


I 


i 


Funthetria  falcatula  Handl.     Oligocene  ; 
Britisli  Columbia,     ^/i- 


Fig.  1582. 


Necromyza  pedata  Scudder.    Miocene  ;  Oeiiingen, 
Baden,    i^/j  (after  Scudder). 


Fig.  1585. 

Chironomus  meyeri  Heer.     Miocene  ;  Oeningen, 
Baden.     6/i  (after  Heer). 


Bibw  sticheli  Handl.     9  Miocene  ;  Gotschee,  Carlnthia 
ö/i  (after  Handlirsch). 


Fig.  1586. 

Falemholus  florigerus  Scudder. 
Miocene  lake  beds  ;  Florissant, 
Colorado.     2/^  (after  Scudder). 


in  the  Miocene  of  Colorado,  wliere  numerous  species  occur,  also  in  British  Columbia, 
and  in  the  Green  River  Eocene  of  Wyoming.  In  the  European  Tertiary  nearly  all 
of  the  modern  families  are  represented,  a  few  examples  of  which  are  shown  in  the 
accompanyiii,!^  Fius.  1582-86.  The  most  interesting  genus  from  the  Florissant  locality 
18  Glossina,  üi^  t^ctse  tly,  two  species  of  which  occur  here  but  not  elsewhere  in  the 
Western  woiid.  ^ 


/• 


4 


SUHPHYLUM  III 


INSECTA 


817 


Order  36.     SUCTORIA  De  Geer  (Siphonaptera,  Äphaniptem  auct.).     (Fleas). 

Small^  wingless,  semijmrasüic  Insects  with  slender  body^  suctorial  mouth  parts,  short, 
cluhbed    antennae,    and    legs    adapted    for 
spriuging ;  tarsi  ßve-jointed.  \, 


Tlie  sole  representative  of  tliis  order  in 
the  fossil  State  is  a  species  of  Palaeopsylla 
Wagn.  (Fig.  1587)  preserved  in  Baltic 
amber  of  Lower  Oligocene  age.  It  is 
interesting  to  note  tliat  Recent  species  of 
this  genus  are  restricted  to  central  Eiirope, 
and  still  inhabit  the  sanie  region  as  in 
mid-Tertiary  tiraes. 


t  Order  37.     PROTOHBMIPTBRA 
Handlirsch. 


Fig.  1587. 

Palaeopsylla  klebsiana  Dampf.     Lower  Oligocene  ; 
lialtic  amber.     36/j  (after  Dampf.), 

Head    small    with    projecting    suctorial 

mouth  parts  differing  from  the  heak  of  true  Hemiptera  only  in  that  the  palpi  of  the 

second  maxilla  are  not  fused  in  the  middle  line.     Body  stout,  with  a  broad  pronotum, 

Wings    horizontally  expanded,  the   venation  primitive,  resembling  that  of  the  Palaeo- 

dictyoptera,  and  ivith  numerous  cross-veins ;  the  anal  area  not  separated  off  by  an  anal 

.  furrow  so   as   to  form  a   distinct   region   or  "  clavus."      Front 

N^.        ^    A     legs  long  and  probably  raptorial. 

The  sole  representative  of  this  group  so  far  as 
known  is  Eugereon  Dohrn  (Fig.  1588),  the  genotype 
of  which  is  the  highly  interesting  E.  boeckingi 
Dohrn  from  the  Lower  Permian  of  Oldenburg. 
It  is  a  generalised  form,  and  may  be  regarded  as 
a  connecting  link  between  the  Palaeodictyop- 
tera  on  the  one  band,  and  the  Homoptera  and 
Hemiptera  on  the  other. 


Fio.  15S8. 

Eiujcreon  boeckingi  Dohrn.     Permian  ;  Birkenfeld  in  Oldenburg. 
3/4  (after  Dohrn). 


t  Order  38. 

PALAEOHBMIPTBRA 

Handlirsch. 

Ä  provisional  group,  estab- 
lished  for  the  reception  of  cer- 
tain  fragmentary  remains, 
mostly  wings,  which  combine 
in  themselves  the  characters  of 
the  Homoptera  and  Hemiptera. 
The  "  clavus "  or  anal  region 
is  separated  by  a  straight  ridge, 
the  corium  and  membrane  are 
not  distinctly  separated. 


Here  are  placed   the  families  Prosbolidae  (typified  by  the  genus  Prosbole  Handl.) 
VOL.  I  3  G 


818 


ARTHROPODA 


THYLUM  VII 


(Ki,  ,589),  and  Scytinoptcidae,  .oü.  .stncted  ^  ^^^'^  ^^'''-^''- 

Order  39.  HEMIPTBRA 
Linnaeus  (Heferoptera 
auct.).     (Bugs). 

Terrestrial  or  aquatic  Insects 
with  sudorial  mouth  parts  con- 
sisting  of  a  mobile  prognathous 
heak  {the  fused  palpi  of  the 
second  maxiUae)  which  contains 
the  setiform  mandihles  and  first 
maxiUae.  Äntennae  never  multi- 
articidate  and  exhibiting  a  variety  of  form,  often  concealed  in  aquatic  forms.  Fore 
wings  covering  the  ahdomen,  their  apical  areas  mostly  memhranous  and  overlapping,^ 
their  basal  moieties  generally  coriaceous,  luith  a  definitely  limited  anal  area  or  "  clavus." 
Hind  wings  concealed  and  loith  a  somewhat  reduced  venation. 
and     depressed ;      prothorax 


Fig.  1589. 

Proshole  hirsuta  Handl.    Upper  Permian  ;  Tichagori,  Russia. 

2/i  (after  Handlirsch). 


J^^^. 


Body  m,ore  or  less  siout 


large ;  legs  similar,  with  few 
tarsal  joints,  and  variously 
adapted  as  for  raptorial, 
saltatorial,  fossorial,  or 
natatory  functions ;  cerci 
wanting. 

Two  main  divisiojis  are 
recognised,  Gymnocerata  or 
terrestrial  Bugs,  and  Crypto- 
cerata  or  aquatic  Bugs. 
Both  groups  are  represented 
in  the  Mesozoic,  but  many 
of  tliese  ancient  types  cannot 
be  included  within  the  limits 
usually  assigned  to  modern 
families.  During  the'  Ter- 
tiary,  on  the  other  hand,  no  forms  existed  which  differ  markedly  from  Recent  types, 
and  nearly  all  of  the  modern  families  are  here  represented.  The  following  named 
families  are  among  the  most  important  of  those  occurring  in  the  Mesozoic : 
t  Archegocimicidae  (typified  by  Archegocimex)  (Fig.  1590),  f  Progonociniicidae, 
t  Eocimicidae,  f  Eonabidae,  f  Hadrocoridae,  f  Cuneocoridae,  Proboscanionidae, 
t  Apopnidae,  f  Pachymeridiidae,  f  Prötocoridae,  f  Sisyrocoridae,  f  Diatillidae, 
Coreidae,  Nepidae,  Belostomidae  (typified  by  the  genus  Mesobelostomum  Haase)  (Fig. 
1591),  Naucoridae,  Notonectidae,  and  Corisidae. 


Fig.  1590. 

Archegocimex  geinitzi 
Handl.  Upper  Lias  ;  Dob- 
bertin  in  Mecklenburg. 
6/i  (after  Handlirsch). 


Fig.  1591. 


Mesobelostomum       deperditum 
Upper    Jura ;    Solenhofen 
(after  Deichmüller). 


Germar. 
Bavaria.       '^/-^ 


Order  40.     HOMOPTERA  Leach.     (Plant-lice,  Wax-bugs, 
Harvest-flies,  etc.). 

Exclusively  terrestrial  Insects  with  hypognathous  suctorial  mouth  parts  having  the 
mme  conformation  as  in  the  Hemiptera.  Äntennae  usually  with  heteronomous  segments, 
often  Short  and  bristle-like.  Wings  as  a  rule  not  overlapping  and  disposed  in  a  more 
tectiform  attitude,  rarely  coriaceous ;  "  clavus  "  in  most  forms  distinctly  bounded.  Hind 
wings  generally  smaller  than  the  forward  pair,  sometimes  with  an  enlarged  anal  lobe. 


SUBPHYLUM  III 


INSECTA 


819 


Prothorax  relatively   large ;    legs  simüar,   or    the   third  imir   adapted  for   springing ; 
ahdomen  without  cerci ;  females  often  with  a  terebra. 

This  group  is  divided  iiito  five  siiborders,  tlie  most  primitive  of  wliicli  is  tlie 
Auchenorliyncha,  ranging  froni  the  Lias  onward.  It  is  represented  in  Mesozoic  rocks 
by  50  species,  in  the  Teitiaiy  by  about  200,  and  in  the  modern  fauna  by  upwards 
of  10,000.  Most  of  the  Jurassic  species  belong  to  the  families  Fulgoridae  (typified 
by  Fulgoridium.  Handl.)  (Fig.  1592) ;  f  Procercopidae  (typified  by  Procercopis  Handl.) 


Fig.  1592 


Fidijoridium  pallidum  Handl.  Upper 
Lias ;  Dobbertln  in  Mecklenburg,  ö/j 
(after  Handlirscli). 


Fig.  1593. 

Prooercopis  alutacea  Handl.     Upper  Lias  ;  Dobbertin  in 

Mecklenburg,    ^/j  (after  Handlirscli). 


(Fig.  1593);  and  Jassidae.  One  species  of  Cicadidae  is  reported  from  the  Cretaceous, 
and  a  dozen  froiii  Tertiary  strata.  The  Fulgoridae,  Cercopidae  and  Jassidae  are 
represented  by  numerous  species  in  the  Tertiary,  and  are  now  fiourishing  families. 
The  suborders  Psylloidea  and  Aphidoidea  have  a  continiious  ränge  from  the  Jura 
onward,  and  the  division  of  Aleurodoidea  is  Tertiary  and  Kecent,  but  is  represented 
by  relatively  few  species.  Plant-lice  (Aphididae)  and  Harvest-flies  (Cercopidae  and 
Cicadidae)  occur  frequently  in  the  Tertiaries  of  Utah,  Wyoming,  Colorado  and  British 
Columbia. 


Olass  2.    APTERYGOGENEA  Brauer  (Apiera  Linnaeus).i 

Piirely  wingless  Insects.     Ahdomen  with  from   six  to  twelve   segments.     No  meta- 
morphosis. 


Order  1.     THYSANURA  LatreiUe. 

Small  Apterygote  Insects  with  orthopteroid,  free  mouth  parts  and  simple  midtiarticu- 
late  antennae.  Compound  eyes  present ;  head  with  hroad  basis  joined  to  thorax^  which 
consists  of  three  divisions ;  tergite  usually  well  developed,  pleurite  and  sternite  small; 
prothorax  as  large  as,  or  larger  than  the  mesothorax.  Abdomen  consisting  of  ten  well- 
developed  segments  and  bearing  distinct  cerci,  a  ter- 
minal filum,  and  reduced  styliform  abdominal  legs  on 
most  of  the  segments. 

The  families  belonging  to  this  group,  Machilidae  Fig.  1594. 

and  Lepismidae,  are  ectotrophous — that  is,  the  mouth      MachjHs  seticornis  (Koch  and 

^  i-i-iiii  ^    •        Berendt).      Lower    Oligocene ;    Baltic 

parts  are  not  buried  111  the  head,  bat  are  arranged  m    amber.    a/j  (after  Koch  and  Berendt). 

the  fashion  usual  among  mandibulate  Insects.      Both 

families  are  represented  in  Baltic  amber  of  Lower  Oligocene  age,  the  genus  Machilis 

Latr.  (Fig.  1594)  being  specially  abundant.     Lepisma  Linn.  is  represented  by  several 

European  and  one  North  American  species  in  the  Oligocene. 

^  Ol/ers,   W.  M.,  Die  Ur-Insekten  (Thysanura  inid  Collenibola  im  Bernstein).     Scliriften  der 
physikal.-ökou.  Ges.  Königsberg,  1907,  vol.  xlviii. ' 


820 


ARTHROPODA  phylum  vii 


Order  2.     CAMPODBOIDEA  Handlirsch  {Archinseda  Haeckel). 

Siiudl  Ajilerinii'ir  i  nfnlvitphovs  hisects  {mouih  parts  or  trophi  reduced  and  huried  in 
fite  had)  vith  f>'elilij~(h'n  loi^'d  njrt;  and  long,  simple,  midtiarticulate  antennae.  Bodtj 
Segments  very  nearly  eqttal ;  ten  well-developed  abdominal  segments,  most  of  them  with 
reduced  styliform  legs ;  cerci  elongate  or  chelate. 

The  so-called  abdominal  legs  in  tliis  gronp  and  in  the  Thysanura  are  appendages 
^vlli(•ll  help  to  support  tlie  abdoraen,  and  serve  also  as  tactile  organs.  They  are 
ciillcil  by  Grassi  false  legs  or  ''  Pseiidoza7npe"  The  Recent  genus  Campodea  Westwood 
occurs  also  in  Baltic  aniber  of  LoAver  Oligocene  age. 

Order  3.     COLLEMBOLA  Lubbock.     (Spring-tails). 

Trophi  reduced  and  huried  in  the  head,  eyes  feehly  developed,  antennae  sometimes 
unequally  segmented.  Thorax  with  very  unequal  segments  hut  with  homonomous  legs. 
Abdomen  consisting  of  not  more  than  six  segments,  the  first  of  ivhich  is  furnished  with  a 
ventral  tuhe  or  papilla,  and  modified  legs  forming  a  springing  apparatus  being  present 
posteriorly. 

About  450  Recent  species  of  Spring-tails  are  known,  and  70  have  been  recorded 
fi'oni  Baltic  amber  of  Lower  Oligocene  age.  The  crustacean  characters  which  we 
find  to-day  in  the  CoUembola,  the  Thysanura,  and  tlie  Ephemerida,  are,  as  pointed 
out  by  G.  H,  Carpenter,  without  doubt  inherited  survivals,  indicating  a  true  relation- 
ship  between  the  two  subphyla  of  Branchiata  and  Insecta. 

Order  4.     PROTURA  Silvestri  (Myrientoma  Berlese). 
Minute  subterraneous  Insects  without  antennae  and  eyes. 
This  Order  is  without  known  representatives  in  the  fossil  State. 

Geological  Range  and  Distribution  of  Insecta. 

It  is  estimated  that  about  1000  Paleozoic,  as  many  Mesozoic,  and  upwards  of 
8000  Cenozoic  Insects  have  been  described  by  different  authors.  The  total  is, 
however,  a  mere  fragment  of  the  insect  fauna  of  past  periods,  and  very  small  in 
comparison  with  the  half  million  species  now  in  existence. 

The  earliest  fossil  Insects  which  have  been  definitely  recognised  are  members  of 
the  Palaeodictyoptera.  Their  first  appearance  in  Europe  is  at  the  base  of  the  Upper 
Productive  Goal  Measures  (Ouralien  or  Stephanien  superienre  of  Commentry,  France, 
and  the  corresponding  'umteres  Obercarbon"  of  German  geologists).  From  the 
Upper  Goal  Measures  of  France,  Germany,  Belgium,  Bohemia,  and  other  localities  in 
l^urope,  and  Irom  the  Lower  Productive  Goal  Measures  (Kanawha  and  Alleglieny 
ormations)  of  Pennsylvania,  Illinois  and  elsewhere  in  the  United  States  and  Canada 
has  been  obtamed  a  large  number  of  highly  interesting  types.i     Other-  representatives 

renilinrwil^fnf  ""'1^'''''^  ""!  ^^-  '^°^"'  ^^^-  B^^ii^wick,  which  has  yielded  a  number  of  insect 
PaeobotaiTv  tnn?rT^  regarded  as  of  Devonian  age,  but  is  now  assigned  on  the  evidence  of 
(livisbro7t  ./pn^^^  ^"^^  ^'"^^^^^'  corresponding  to  the  Kanawha  Group  (upper 

pZZI  .^.It  f  '^/n^P^^'^^^  ''''''^  '''''S,  described  by  Moberg  under  the  !>ame  of 
Anot  r^oub  ful  f;  "^  the  Graptohte  beds  of  Sweden  is  probably  not  of  Arthropod  nature. 
M^^Surit  ofr.,^^^^^^^^  '\'  '°-'""^^  ^'^^^^oUattina  douvül J  of  Brongniartf  from  the 
S  f^e    l^^^^^^  T  Hl  erpreted  by  Agnus  as  part  of  the   pleural  lobe  of  a  Trilobite. 

irMiiS^sTlns..?.  ,  .  '\\"'^n'  ?«^""ianrocksof  the  south-east  of  Ireland,  but  no  indubitable 

fouu.l  .t    Fnrnl.v    r-  i'.'"',  <-=irboniferous  have  been  as  yet  forthcoming.     Tlie  insect  remains 

f-i,.  th..  Fkr  ia.it  1  p'l  ',"■'  ""'"^  ^^'°"^^*  *"  ^''  ^f  ^''"^'^''  ^««tead  of  Triassic  age.  Those 
fonue.lv  '^'  ^'''  "°''  ^■^*"^"-«*^  to  the  Miocene,   instead  of  to  the  Oligocene,   "" 


11  e,  f^s^^M 

4 


suBPHYLüM  III  INSECTA  821 

of  various  primitive  groiips  are  known  froni  tlie  Perniiaii  of  Riissia,  Germany,  West 
Virginia,  Kansas  and  Colorado,  so  that  on  tlie  wliole  we  are  fairly  well  acquainted 
with  these  heterometabolic  ancestors  of  modern  Orders.  Unfortunately,  liowever,  very 
little  evidence  is  fortlicoming  from  the  Trias,  during  whicli  era  the  transition  from 
tlie  lieterometabolic  to  the  holometabolic  stage  probably  took  place.  Nevertheless, 
a  few  fossil  remains  are  known  from  tlie  Trias  of  Sweden,  Germany,  Austria, 
Switzerland  and  China.  Niimerous  tracks  of  supposed  Insects,  and  also  what  are 
believed  to  be  the  aquatic  larvae  of  an  alder-fly  {Mormolucoides  articulatus  Hitchcock), 
occiir  in  the  dark  shales  of  the  Connecticnt  Valley  Trias. 

A  fairly  rieh  insect  fauna  has  Ijeen  discovered  in  the  Lias  of  Schambelen  in 
Aargau,  Switzerland,  Dobbertin  in  Mecklenburg,  Brunswick,  Weyer  in  Austria,  and 
several  localities  in  Somerset,  Gloucestershire  and  Yorkshire,  England.  A  few 
remains  are  preserved  in  the  Stonesfield  Slate  near  Oxford,  England,  and  in  strata 
of  the  same  age  in  Siberia  ;  and  a  considerable  number  of  species  occurs  in  the  Purbeck 
of  the  southwestern  counties  of  England.  Eichest  of  all,  however,  is  the  Upper 
Jurassic  insect  fauna,  especially  that  which  is  found  in  the  Lithographie  Stoiie 
(Kimmeridgian)  of  Bavaria.  Contrariwise,  the  ^Cretacegus  is  markedly  deficient  in 
Information  respecting  this  group  of  invertebrates. 

Tertiary  Sediments  have  yielded  an  enormous  quantity  of  well-preserved  insect 
remains.  Aniong  the  more  important  localities  that  have  furnished  material  of  this 
nature,  mostly  of  mid-Tertiary  age,  may  be  mentioned  the  freshwater  deposits  of 
Florissant,  Colorado,  Aix-en- Provence,  Oeningen  on  Lake  Constance  in  Baden,  Radoboj 
in  Croatia,  Eott  (Upper  Oligocene  lignite)  near  Bonn  on  the  Rhine,  Brunnstatt  in 
Alsace,  Sieblos  in  Bavaria,  Bilin  in  Bohemia  and  Gabbro  in  Tuscany ;  also  the 
Oligocene  strata  at  Quesnel  in  British  Columbia,  and  the  Green  River  Eocene  of 
Wyoming,  western  Colorado  and  eastern  Utah.  But  by  far  the  largest  and  itiost 
varied  assemblage  of  Tertiary  insect  remains  is  obtained  from  Oligocene  amber  in 
East  Prussia. 

Finally,  in  the  Pleistocene,  the  interglacial  clays  of  Switzerland,  Germany  and 
Ontario,  the  peats  of  northern  France  and  England,  the  ozokerite  of  Galicia,  and  the 
lignites  of  Hösbach  in  Bavaria,  deserve  mention  as  localities  which  .have  furnished 
fossil  insect  remains.  In  the  accompanyiiig  table  is  indicated  the  geological  ränge  of 
the  different  orders  of  Insects. 

[The  preceding  chapter  on  Insecta  has  been  prepared  especially  for  the  present  work  by 
Professor  Anton  Handlirscli,  of  the  Imperial  Museum  of  Natural  History  at  Vienna.  A 
few  minor  eniendations  have  been  suggested  by  Dr.  W.  J.  Holland,  Director  of  the  Carnegie 
Museum  at  Pittsburgh,  and  otliers  by  Professor  T.  D.  A.  Cockerell,  of  the  University  of 
Colorado. — Editor,] 


822 


ARTHROPODA 


PHYLUM  VII 


Taiu.k  showing  THE  Vertical  Range  op  Fossil  Insects. 


Orders. 


Class  I.  Pterygogenea 

1.  Palaeodictyoptera 

2.  Mixotermitoidea 

3.  Reculoidea 


4.  Protortlioptera 

5.  Orthoptera 

6.  Phasmoidea 

7.  Dermaptera 

8.  Diploglossata 

9.  Thysanoptera 

10.  Protoblattoidea 

11.  Blattoidea 

12.  Mantoidea 

13.  Isoptera  . 

14.  Corrodentia 

15.  Mallopliaga 

16.  Siphunciüata 

17.  Coleoptera 

18.  Hymenoptera 

19.  Hadentomoidea 

20.  Embioidea 


21.  Sypliaropteroidea 

22.  Hapalopteroidea 

23.  Perlaria   . 

24.  Protepliemeroidea 

25.  Plectoptera 

26.  Protodonata     . 

27.  Odonata  . 

28.  Megaloptera     . 

29.  Raphidioidea  . 

30.  Neuroptera 


31.  Megasecoptera 

32.  Panorpatae 

33.  Trichoptera 

34.  Lepidoptera 

35.  Diptera    . 

36.  Suctoria  . 


37.  Protohemii)tera 

38.  Palaeoheniiptera 

39.  Heniiptera 

40.  Homoptera 


Class  II.  Apterygogenea  (Aptera) 

1.  Tliysanura 

2.  Canipodeoidoa  . 

3.  CoUcmbola 

4.  Protura    .... 


^S 


I 


INDEX 


[Names  of  genera  and  subgenera  regarded  as  synonyms  are  priuted  in  italics,  all  otliers  in  Roman.  ] 


Abacocrinus,  194 
Ähatus,  296 
Ablacomya,  449 
Abra,  495 
Abracrinus,  194 
Ahrotocrinns,  222 
Acacocrinus,  194 
Acambona,  414 
Acanthactinella,  62 
Acantherpestes,  793 
Acanthina,  558 
Acanthinites,  648 
Acanthocaris,  751 
Acanthoceras,  669 
Acanthocites,  513 
Acanthoclaclia,  342 
Acanthoclema,  344 
Acanthoclymenia,  628 
Acanthocrinus,  188 
Acanthocyathus,  95 
Acanthocystites,  150 
Acanthodictya,  61 
Acantholithus,  112 
Acanthonaiitilus,  606 
Acanthopleura,  513 
Acanthospongia,  62 
Acanthotelson,  756 
Acanthoteiithis,  683 
Acanthothyris,  400 
Acasta,  746 
Acaste,  726 
Acavvis,  576 
Acentrotremites,  172 
Acervularia,  86 
Aceste,  297 
Acestra,  62 
Acharax,  438 
Achradocrinns,  219 
Achradocystites,  151 
Achrochordociinus,  232 
Acila,  440 
Acdeistoceras,  611 
Aclisina,  538 
Acloeodictya,  61 
Acmaea,  520 
Acritis,  371    f 
Acrochordiceras,  640 
Acrocrinus,  201 
Acroculia,  541 
Acrogenia,  346 
Acroidaris,  275 
Aoropora,  107 
Acrosalenia,  279 
Acrothele,  376 
Acrothyra,  376 
Acrotreta,  376 
Acrura,  256 
Actaeonella,  566 
Actaeoriina,  566 
Acteocine,  568 
Acteon,  565 
Actinacis,  107 
Actinocamax,  682 


Actinoceramus,  447 
Actinoceras,  609 
Actinoconchus,  418 
Actinocrinus,  197 
Actinodesina,  444 
Actinodiclya,  61 
Actinodonta,  455 
Äctinomya,  468 
Actinopora,  322 
Actinopteria,  448 
Actinosepia,  688 
Actinostonia,  341 
Actinostreon,  450 
Actinostroma,  122 
Actinotaxia,  326 
Adacna,  490 
Adelactaeon,  566 
Adehtstrea,  101 
Adeloblatta,  803 
Adelopthalmus,  783 
Adeonella,  339 
Adolfia,  410 
Adranaria,  440 
Aechmina,  738 
Aeger,  761 
Aegiope  405 
Aeglina,  721 
Aegoceras,  656 
Aeolopneustes,  282 
Aeropsis,  297 
Aeschnidium,  810 
Aesiocrinus,  225 
Aesiocystis,  159 
Aetea,  348 
Aethocystis,  157 
Aetostreon,  450 
Aganides,  631 
Agaricia,  103 
Agaricocrinus,  196 
Agassiceras,  657 
Agassizia,  296 
Agassizocriniis,  224 
Agathelia,  95 
Agathemera,  800 
Agabhiceras,  641 
Agelacrinus,  159,  156 
Agina,  499 
Aglaspis,  776 
Aglithodictya,  61 
Agnesia,  524 
Agnostus,  710 
Agoniabites,  630 
Agrawlos,  717 
Agria,  482 
Agriocrinus,  199 
Agrion,  811 
Aguthasia,  404 
Aipoceras,  606 
Akera,  567 
Alarla,  550 
Albertella,  717 
Alecto,  319 
Alectrion,  556 


Alectryonia,  450 
Alexia,  574 
Alipes,  551 
AUagecrinus,  209 
Allionia,  237 
Allocrinus,  191 
Allocystites,  155 
AUodesma,  470 
AUomorphina,  29 
AUonema,  318 
AUonychia,  445 
Allopagus,  469,  489 
AUoprosallocrinus,  195 
Allorhynchus,  398 
AUorisma,  465 
Alocolytoceras,  652 
Aluta,  735 
Alveolina,  39 
Alveolites,  114 
Alveopora,  107 
Amaltheus,  659 
Amauropsis,  543 
Ainbites,  633 
Amblypneustes,  282 
Amblypygus,  289 
Amblysiphonella,  71 
Ambocoelia,  412 
Ambonycliia,  445 
Amiella,  786 
Amicula,  513 
Amiskwia,  135 
Amita,  444 
Ammobaculites,  26 
Ammodiscus,  25 
Ammolagena,  25 
Amnicola,  545 
Amnigenia,  451 
Aviorphocystis,  152 
Amperleya,  530 
Ampheristocrinus,  218 
Amphiastraea,  98 
Amphibola,  573 
Amphiceras,  657 
Amphichaena,  495 
Amphiclina,  419 
Amphiciinodonta,  419 
Amphicoelia,  445 
Aniphicrinus,  205 
Amphidesma,  495 
Amphidonta,  450 
Amphidromus,  576 
Aiiiphigenia,  400 
Amphilichas,  721 
Amphion,  725 
Amphipeltis,  758 
Amphipora,  124 
Amphispongia,  62 
Amphistegina,  34 
Amphistrophia,  385 
Amphithelion,  59 
Amphitomella,  418 
Amphiura,  256 
Amphora,  197 


Amphoracrinus,  197 
Amplexopora,  336 
Amplexus,  83 
Ampulla,  561 
Ampullina,  543 
Ampyx,  712 
Amusium,  458 
Amygdalocystites,  151 
Amynilispes,  793 
Anabacia,  103 
Anabaia,  417 
Anadara,  443 
Anagyrnnites,  645 
Ananchytes,  292 
Anapella,  498 
Anaphragma,  339 
Anarcestes,  629 
Anasirenites,  648 
Anaspides,  755 
Anastomopora,  342 
Anasbrophia,  394 
Anathyris,  417 
Anatimya,  466 
Anatina,  466 
Anabinella,  498 
Anatomites,  639 
Anazyga,  408 
Anchura,  551 
Ancilla,  562 
Ancillaria,  562 
Ancistroceras,  601 
Ancistrocrania,  379 
Ancryopyge,  723 
Anculosa,  548 
Ancyloceras,  670 
Ancylus,  575 
Androgynoceras,  656 
Angaria,  529 
Angelinoceras,  601 
Anisactinella,  418 
Anisocardia,  471 
Anisocrinus,  203 
Anisophyllum,  84 
Anisothyris,  499 
Anisotrypa,  335 
Anodonta,  455 
Anodontites,  455 
Anodontopsiif,  470 
Anolcites,  648 
Anolotichia,  328 
Anomactinella,  418 
Anomalanthus,  286 
Anomalina,  33 
Anomalocaris,  733 
Anomaloceras,  605 
Anomalocrinus,  213 
Anomalocystites,  150 
Anomalodonta,  445 
AnomahmUs,  72 
Anonialospongia,  72 
Anomia,  461 
Anonioclonella,  56 
Anomplialus,  532 


824 


Aiini-ara,  .117 
Aniipli.'i.  ■■'•>'■> 
Aiinpldcnas,  f>06 
Aiioploplioia,  452 
AiioplotlH'Ca,  41() 
Anuptvcliia,  537 
Antalis,  50i» 
Antedon,  236 
Aiitheinocrinufi,  189 
Anthocrinns,  216 
Aiithocystis,  153 
Anthoiiyia,  474 
Anthracochiton,  512 
Anthracomartus,  791 
Anthracomya,  452 
Anthraconectes,  783 
Anthnu-opeltis,  774 
Anthnicophausia,  759 
Anthmcoptera,  451 
AnthriKX^sia,  451 
Aiithrapalaenion,  757 
Antinomia,  403 
Aiitil)leura.  439 
Antiptychia,  407 
Antirhynclwndla,  394 
Antocyrtis,  44 
Anuscula,  440 
Aorocrinus,  19G 
Aparchites,  737 
Apasmophyllum,  ^4 
Aphanaia,  449 
Apheleceras,  604 
Aphetoceras,  600 
Aphragmites,  596 
Aphrostroma,  124 
Aphyllites,  630 
Apioceras,  611 
Apiocrinus,  230 
Apiücystites,  154 
Apion,  805 
Apioceras,  608 
Ai)orrhais,  551 
Apricardia,  477 
Apsendesia,  321 
Aptychopsis,  754 
Aptyxiella,  549 
Aptyxis,  549 
Apus,  733 
Arachnocrinus,  219 
Arachnocystites,  152 
Arachnoides,  288 
Araeacis,  96 
Arbacia,  281 
Arbusculües,  390 
Area,  443 
Arcanopora,  346 
Arcestes,  642 
Archaediscus,  34 
Archaeocidaris,  300 
Archaeocrinus,  188 
Archaeocyathus,  105 
Archaeolepas,  744  • 
Archaeoniscus,  758 
Archaeoplax,  767 
Arcliaeoscyphia,  53 
Archaeosphaerina,  37 
Arcliarenicola,  139 
Archastwins,  248 
Archegetes,  813 
Archegoci-nim:,  818 
Archegocystis,  155 
Archidesmus,  793 
Archimedes,  341 
Archinacella,  520 
Archiorhynchus,  805 
Architarbus,  791 
Architectonica,  538 
Architipnla,  815 
Archiulus,  793 
Arcomya,  466 
Arcoiuyopsis,  438 
Arcnjmgia,  494 
Arctitrota,  387 
Arenicola,  141 
Areünunna,  715 
Argas,  753 


TEXT -BOOK  OF  PALEONTOLOGY 


Ar(i(ixter,  248 
Argia,  811 
Argina,  443 
Argonauta,  688 
Argopa tagus,  297 
Argyrothea,  365 
Argyrotheca,  405 
Aricardium,  490 
Arieticeras,  658 
Arietites,  655 
Aristerella,  462 
Aristocystites,  150 
Aristozoe,  752 
Arnioceras,  655 
Arpadites,  648 
Arrhoges,  551 
Artemis,  492 
Arthaberites,  635 
Arthracantha,  200 
Arthraster,  251 
Arthroclema,  343 
Arthrolycosa,  790 
Arthropliycus,  141 
Arthropleura,  758 
Arthropora,  345 
Arthroracliis,  710 
Arthrostylus,  342 
Arystidicta,  61 
AsaphelluH,  719 
Asaphis,  495 
Asaphus,  719 
Ascidaspis,  722 
Ascoceras,  596 
Ascocystites,  160 
Ascodictyon,  318 
Asemoblatta,  803 
Aspenites,  634 
Aspergillum,  468 
Aspidiscus,  99 
Aspidites,  645 
Aspidocaris,  754 
Aspidoceras,  665 
Aspidodiadema,  276 
Aspidophyllum,  86 
Aspidopora,  333 
Aspidosoma,  249 
Aspidothyris,  401 
Aspidura,  256 
Assilina,  36 
Assiminea,  545 
Astacus,  764 
Astarte,  472 
Astartopsis,  457 
Asteractinella,  62,  63 
Asterias,  247,  252 
Asteriatites,  237 
Asterina,  251 
Asteroblastus,  167 
Asteroceras,  655 
Asterocrinus,  201 
Asteroderma,  57 
Asteropyge,  726 
Asthenodonta,  452 
Asthenosoma,  278 
Asthenothaerus,  467 
Astieria,  664 
Astraemorpha,  104 
Astraeospongia,  62 
Astraliuni,  528 
Astrangia,  98 
Astreopora,  108 
Astrhelia,  95 
Astrocladia,  55 
Astrocnida,  255 
Astrocoenia,  101 
Astrocoma,  237 
Astroconia,  62 
Astrocrinus,  172,  190 
Astrocystites,  160 
Astroides,  76,  106 
Astropecten,  247,  249 
Astropkyton,  255 
Astropyga,  278 
Astrorhiza,  24 
A.t!ih,rn,n,.,-22\ 
Ashihnnn.nun,  56 


;  Astylospongia,  55 
I  Asyniptoceras,  6Lü 

Atactodea,  498 
j  Atactopora,  338 
[  Atactoporella,  331 
'■  Ataxaster,  248 
j  Ataxioceras,  664 

Ataxocrinus,  213 
I  Ateleocystites,  150 
i  Atelestocrinus,  218 

Atergatis,  767 

Athleta,  561 

Athyris,  417 

Atikakania,  105 

Atlanta,  536 

Atocus,  806 

Atoma,  564 

Atomodesma,  449 

Atops,  713 

Atractites,  681 

Atretia,  400 

Atrina,  446 

Atrypa,  409 

Atrypina,  408 

Attoides,  790 

Aturia,  603 

Atys,  568 

Aucella,  449 

Aulacoceras,  680 

Aulacophyllum,  83 

Aulacopleura,  715 

Aulacorhynchus,  389 

Aulacostephanus,  665 

Anlacotliyris,  406 

Aulocopium,  53 

Aulocrinus,  224 

Aulonotreta,  371 

Aulophyllum,  86 

Aulopora,  116 

Aulosteges,  891 

Anricula,  574 

Aurigerus,  665 

Aurina,  561 

Austinella,  381 

Austinocrinus,  233 

Austriella,  399 

Autodetus,  543 

Avellana,  567 

Avimola,  447 

Aviculopecten,  457 

Aviculopinna,  446 

Axinopsis,  487 

Axinus,  487 

Axosmilia,  100 

Aysheaia,  136 

Azara,  499 

Azor,  495 

Babinka,  444 
Bactrites,  629 
Bactrocrinus,  218 
Bactropora,  343 
Bactropiis,  752 
Bactrotheca,  571 
Bactryninm,  389 
Baculina,  654 
Baculites,  654 
Baculocystites,  150 
Badiotella,  460 
Badiotites,  644 
Baerocrinus,  211 
Baetis,  809 
Bairdia,  740 
Bakewellia,  447 
Balanocrinus,  233 
Balanocystites,  151 
Balanophyllia,  105 
Balantionella,  64 
JUüamtium,  570 
Baianus,  746 
Balatonites,  647 
Baltoceras,  598 
Banibaganites,  635 
Banffla,  141 
Barbarothea,  815 
Barbatia,  443 


Baroda,  494 

Barrandeites,  638 

Barnmdella,  395 

Barrandeoceras,  600 

Barrandeocrinus,  195 

Barrettia,  484 

Barroisella,  374 

Barroi  sia,  71 

Barroisiceras,  669,  67^ 

Bartlettia,  455 

Barycrinus,  218 

Baryphyllia,  99 

Baryphyllum,  82 

Barysmilla,  101 

Basilicus,  719 

Basiliola,  400 

Basterotia,  469 

Bathmoceras,  597 

Bathybius,  17 

Bathycoelia,  382 

Bathycrinus,  230 

Bathycyathus,  95 

Batbynotus,  715 

Bathysiphon,  24 

Bathytoma,  563 

Bathyurellus,  718 

Bathyuriscus,  718 

Bathyurus,  718 

Batillus,  529 

Batissa,  474 

Batocrinus,  195 

Batolites,  482 

Batostoma,  338 

Batostomella,  335 

Battersbyia,  87 

Bayania,  537 

Bayanoteutliis,  683 

Baylea,  524 

Bayleia,  478 

Bdellacoma,  251 

Beacbia,  401 

Becksia,  67 

Beecheria,  403 

Bela,  563 

Belemnitella,  683 

Belemnites,  681,  683 

Belemnocrinus,  215 

Belemnocystis,  151 

Belemnoijsis,  682 

Belenmosis,  683 

Bolemnoteuthis,  684 

Belgrandia,  545 

Belinurus,  773 

Bellardia,  550 

Bellard iella,  564 
Belleroplion,  522 
Beloceras,  631 
Beloptera,  683 
Belopterina,  683 
Belosepia,  686 
Belosepiella,  686 
Beloteuthis,  688 
Beitina,  783 
Bembexia,  525 
Beneckeia,  646 
Berenicea,  819 
Berthelinia,  464 
Beyrichia,  738 
Beyrichiella,  738 
Beyrichiopsis,  738 
Beyricliites,  647 
Beyrichocrinus,  195 
Beyrichona,  735 
Bicavea,  323 
Bicia,  373 
Bicrisina,  320 
Bidentia,  732 
Bidiastopora,  320 
Bifida,  416 
Biflabellaria,  326 
Bifrontia,  538 
Bigenerina,  29 
Billingsella,  380 
Billinqsia,  372 
Billingsites,  597 
Bilobites,  383 


INDEX 


825 


J3iloculina,  38 
BiradioliUs,  481 
Birüstrites,  482 
Bisidmonea,  H20 
Bitliinia,  544 
Bittium,  550 
Bittnerula,  413 
Bitubigera,  820 
Bldirocrinus,  197 
Blanchardm,  808 
Blastoidocrinus,  167 
Blauneria,  574 
Boliemura,  254 
Boletia,  282 
Bolivina,  28 
Bollia,  738 
Bolma,  528 
Boutaea,  4ö7 
Borelis,  39 
Borsonia,  564 
Boskovicia,  544 
Bosnites,  635 
Bosquetia,  740 
Bothriocidaris,  270 
Bothrocorbula,  499 
Bothromicromus,  813 
Büthryocanipe,  44 
Botriopygus,  290 
Botryllopora,  330 
Botryocrinus,  221 
Botryodictya,  60 
Botsfordia,  375 
Bouchardia,  407 
Bourgetia,  537 
Bourgueticrinus,  229 
Brachiocrinus,  212 

Brachiospongia,  62 

Brachylepas,  745 

Brachymerus,  394 

Brachyprion,  385 

Brachypyge,  791 

Brachythyris,  410 

Brachytrema,  539 

Bradoria,  735 

Bradyblatta,  803 

Bralimacrinus,  200 

Branchipodites,  732 

Branconia,  395 

Brasilia,  658     , 

Brechites,  468 

Breynia,  297 

Briarocrinus,  191 

Brilonella,  524 

BHssomorpha,  297 

Brissopatagus,  297 

Brissopsis,  297 

Brissus,  297 

Brocchia,  541 

Brodieia,  658 

Broeckia,  439 

Broeggeria,  371 

Brongniartiella,  813 

Broiitftopsis,  720 

Brontes,  720 

Bronteus,  720 

Bryopa,  468 

Bucanella,  521 

Bucaiiia,  521 

Bucanopsis,  523 

Bucanospira,  530 

Buccinopsis,  557 

Buccimdus,  565 

Buccinum,  556 

Bücliiceras,  671 

Buchiola,  439 

Buchites,  648 

Buddliaites,  645 

Bubiniiia,  29 

Biiliiimlus,  576 

Bulla,  567 

l'.nUaca,  568 

Hulliiiia,  567 

BiiUiiia,  566 

Bullimlla,  568 

Bullinula,  566 

Bumastus,  720 


Bundenbachia,  254 
Bunodella,  777 
Bunodes,  777 
Burgessia,  733 
Buria,  769 
Bursa,  555 
Bursacriims,  225 
Bushia,  467 
Buskopora,  330 
Busycon,  557 
Buthus,  770 
Byssocardiuin,  490 
Byssomya,  499 
Byssonychia,  445 
Byssopteria,  445 
Bythinella,  545 
Bythocrinus,  229 
Bythocypris,  740 
Bythopora,  335 
Bythotrypa,  328 

Cacabocrinus,  191 
Cactocrinus,  197 
Cadoceras,  663 
Cadomella,  389 

Cadomia,  440 

Cadomites,  663 

Cadomoceras,  658 

Cadulus,  510 

Caecella,  498 

Caecum,  547 

Cainocrinus,  233 

Calais,  688 

Calamocrinns,  238 

Calamophyllia,  99 

Calamopora,  113 

Calapoecia,  114 

Calappa,  765 

C(xlathocrinus,  225 

Calathospongia,  61 

Calcarina,  33 

Calceocrinus,  213 

Calceola,  88 

Caleidocrinus,  206 

Callavia,  714 

Callianassa,  764 

Callicrinus,  192 

Calliderma,  250 

Calliostoina,  532 

Callistochiton,  513 

Callistoplax,  513 

Callizoe,  752 

Callocardia,  491,  493 

Callochiton,  513 

Callocystites,  153 

Callogonia,  491 

Callonema,  538 

Callopegma,  53 

Callopoma,  529 

Callopora,  337 

Calloporella,  337 

Calloporina,  337 

Callotrypa,  335 

Calostylis,  105 

CalpiocrinuH,  203 

Calvetina,  353 

Calycanthocrinus,  208 

Calymene,  724 

Calyiune,  294 

Calyptogena,  476 

Calyptraea,  542 

Camarella,  394 

Camarium,  416 

Cainarocrinus,  160,  190 

Caniarophorella,  396 

Camarophoria,  395 

Catuarospira,  416 

Cameroceras,  595 

Cainerospongia,  68 
j  Cainerotheca,  571 
I  Camerothyris,  407 
I  Camitia,  532 
i  Campodea,  820 
;  Campophylluni,  84 
j  Catuptocrinus,  201 
I  Camptonectes,  458 


( 'am]iyl(irej)halus,  782 

Cainpyloccras,  608 

Campylosepia,  686 

Canadia,  136 

Canadocystis,  151 

Canavarites,  660 

Cancellaria,  562 

Cancer,  767 

Cancrinus,  763 

Caninia,  83 

Canistrocrinus,  189 

Cantantostoma,  525 

Cantharidus,  532 

Cantharus,  556 

Capellinia,  395 

Caphyra,  717 

Caprina,  479 

Caprinella,  480 

Caprinula,  480 

Capulus,  541 

Carabocrinus,  217 

Caratomus,  289 

Carbonarca,  442 

Carbonia,  739 

Carbonicola,  451 

Carcinocarcinns,  767 

Carcinosoma,  783 

Cardiaster,  294 

Cardilia,  498 

Cardinia,  452 

Cardinocrania,  379 

Cardiocaris,  754 

Cardioceras,  663 

Cardiocystis,  160 

Cardiola,  439 

Cardiolites,  751 

Cardiomorpha,  439 

Cardiomya,  469 
Cardita,  475 
Carditamera,  476 
Carditella,  476  , 

Cardium,  489 
Carduocrinus,  221 
Caricella,  561 
Carinaria,  536 
Carinaropsis,  523 
Carinifer,  326 
Carinopora,  341 
Carnarvonia,  750 
Carnites,  635 
Carolia,  461 
Carolicrinus,  194 
Carosyphaera,  42 
Carpenteria,  33,  451 
Carpenteroblastus,  172 
Carpenterocrinus,  232 
Carpocrinus,  194 
Carpocystis,  156 
Carpomanon,  56 
Carpospongia,  56 
Carterella,  57 
Carterina,  124 
Carychium,  574 
Caryocaris,  751 
Caryocrinus,  153 
Caryocystites,  152 
Caryomanon,  56 
Caryophyllia,  95 
Caryophyllites,  239 
Caryospongia,  56 
Casearia,  65 
Cassianella,  448 
Cassianocrinus,  225 
Cassidaria,  554 
Cassidula,  574 
Cassidulina,  29 
Cassidulus,  290 
Ikissiope,  546 
Cassis,  555 
Vastanocrinus,  190 
Castocrinus,  213 
Catazyga,  408 
(\itenipora,  117 
Catillocrinus,  214 
Vatillus,  447 
Catopygus,  290 


Catosira,  537 
Catulloceras,  658 
Caunopora,  123 
Cavaria,  324 
Caveii,  324 
Cavolina,  570 
Cea,  323 
Cellaria,  348 
Cellepora,  350,  353 
Celleporia,  353 
Cellularia,  348 
Cellulipora,  320 
Celtites,  640 
Cenoceras,  607 
Cenocrinus,  233 
Cenomanites,  668 
Cenosphaera,  42 
Centrechinus,  277 
Centriocrinus,  191 
Centroceras,  606 
Centrocrinus,  199 
Centronella,  400 
Centrotheca,  571 
Cephalograptus,  130 
Cephaloraphidites,  51 
Ceramella,  346 
Ceraviocrinus,  219 
Ceramophylla,  328 
Ceramopora,  327 
Ceramoporella,  327 
Ceratarges,  722 
Ceratiocaris,  750 
Ceratisolen,  496 
Ceratites»  647 
Ceratocephala,  722 
Ceratocystis,  151 
Ceratodictya,  60 
Ceratolichas,  722 
Ceratopsis,  738 
Ceratopyge,  717 
Ceratosiphon,  551 
Ceratostreon,  450 
Ceratotheca,  571 

Ceratotrochus,  94 

Ceratozona,  513 

Ceraurus,  724 

Cercomya,  466 

Ceriocava,  326 

Ceriocrinus,  225,  231 

Cerionites,  72 

Ceriopora,  326 

Ceritella,  549 

Cerithidea,  550 

Cerithinella,  549 

Cerithiopsis,  550 

Cerithium,  550 

Cermatia,  793 

Cernina,  543 

Ceromya,  465 

Cerylonopsis,  S05 

Cetoconcha,  469 

Cetomya,  469 

Chaena,  500 

Chaenocaris,  753 

Chaenomya,  439 

Chaenopea,  500 

Chaetetes,  117 

Chaetopleura,  513 

Chalnodictyon,  340 

Chalmasia,  449 

Chama,  477 

Chaperüi,  480 

Charionella,  416 

Chartronia,  660 

Chascothyris,  401 

Chasmatopora,  340 

Chasmops,  727 

Chauliodes,  812 

Chauliodites,  811 

Clieiloceras,  631 

Cheirocrinus,  154,  213 

Cheiropteraster,  251 

Cheimrus,  724 

Chelifer,  789 

Chelocriniis,  225 

Chevmitzia,  537 


826 


TEXT -BOOK  OF  PALEONTOLOGY 


Cheiiendopora,  59 
Chemypus,  551 
Chicagocrlnus,  193 
Chicoreus,  558 
Chilina,  574 
Chilocyclus,  53S 
Cliilopora,  326 
Chiloporella,  328 
Chilostomella,  29 
Cliilotrypa,  330 
Chiridota,  313 
Chiton,  513 
ChiUmellus,  513 
ChlaclocHnus,  232 
Chlamydoconcha,  448 
Chlamys,  457' 
Chlidoiiophora,  404 
Choanoceras,  596 
Vhoffatia,  663 
CholDcrinus,  203 
Chonaxis,  85 
Chondrostroma,  124 
Chonediitoii,  512 
Choneplax,  513 
Clionetella,  389 
Chonetes,  389 
Chonetina,  389 
Chonop«ctus,  391 
Choiiopliyllum,  85 
Chonostegites,  116 
Chonostrophia,  389 
Chorlplax,  512 
Choristites,  410 
Choristoceras,  6i9 
Choristixion,  494 
Chresmoda,  799 
Christania,  385 
Chrysodomus,  557 
Chrysomelon,  278 
Chrysostoma,  532 
Chthamalus,  747 
Cibolocrinus,  225 
Cicatrea,  472 
Cidaris,  372 
Cülaroblastiis,  171 
Cigara,  151 
Ciniitaria,  465 
Ciiicta,  407 
Cinulia,  567 
Circe,  493 
Circopora,  124 
Cirrus,  531 
Cirsotrema,  538 
Cistella,  405 
Citrocystis,  152 
Cladangia,  98 
Cladiscites,  643 
Cladochonus,  116 
Cladocora,  97 
Clwiocrinus,  206 
Cladopora,  114 
Clanculus,  531 
Clarkella,  392 
Clathrcxlictyon,  123 
Clathropora,  345 
Clathrospira,  b'lb 
Clathrospongia,  60 
Clathurella,  564 
Clausa,  324 
Clausilia,  576 
Clava,  550 
CUmiehhishis,  170 
Clavagella,  468 
Clavatula,  563 
Clav»!lla,  559 
Claviclausa,  324 
Clavisparsa,  320 
Clavulina,  29 
Cleidophorus,  440 
Cleidotheea,  571 
Ck'iocrimis,  186 
Cleiotliyridina,  418 
VhiothyrU,  417,  418 
Cli!ist<!cliiinis,  2>)7 
ClevuitiKrinus,  199 
dementia,  492 


Cleodictya,  61 

Clmlora,  570 

Cleonoceras,  667 

Clesydrospongia,  61 

Clidiopliora,  467 

Clidochirus,  204 

Cliftonia,  387 

Climacammina,  29 

Climacograptus,  130 

Climactichnites,  142 

Clinoceras,  611 

Clinopistha,  438 

Clinopora,  321 

Clintonella,  409 

Clinura,  563 

Clio,  570 

Clionites,'648 

Clionychia,  445 

Clisiophyllum,  85 

Clisocolus,  491 

Clisospira,  543 

Clitambonites,  392 

Clonocrinus,  190,  190 

Clonopora,  321 

Clorinda,  395 

Closterocrinus,  218 

Clydonautilus,  (i02 

Clydonites,  648 

Clymenia,  628 

Clymenonautilus,  602 

Clypeaster,  285 

Clypeina,  321 

Clypeoceras,  645 

Clypeus,  290 

Clypites,  634 

Cnemidiastrum,  57 

Cnemidium,  57 

Cnisma,  442 

Coccocrinus,  199 

Coccophyllum,  101 

Coccoseris,  112 

Coccoteuthis,  687 

Cochlearia,  538 

Cochloceras,  650 

Cochlodesma,  467 

Cochlolepas,  542 

Codakin,  486 

Codaster,  168 

Codechinus,  278 

Codiacrinus,  221 

Codiacystis,  155 

Codiopsis,  277 

Codoceras,  612 

CodoTiaster,  168 

Codonites,  169 

Coelastarte,  472 

Coeliocrinus,  223 

Coelocentrus,  527 

Coeloceras,  662 

Coeloclema,  328 

Coeloconus,  343 

Coelocorypha,  59 

Coelocrinus,  187,  196 

Coelocystis,  154 

Coelodon,  467 

Coeloeanlus,  525 

Coelogasteroceras,  605 

Coeloraa,  766 

Coelomactra,  497 

Coelonautilus,  604 

Coelopleurus,  281 

Coeloptychium,  67 

Coelosmilia,  100 

Coelospira,  417 

Coelostylina,  537 

Coenagrion,  811 

Coenites,  114 

Coenocyathus,  95 

Coenocystis,  157 

Voenograptus,  130 

Coenothyris,  407 

Coleoloides,  572 

Coleolus,  572 
j  CoUina,  662 
1  Collonia,  529 
I  Collyrites,  292 


Colobocentrotus,  283 
Coloceras,  604 
Colospongia,  71 
Colpocaris,  751 
Colpoceras,  595 
Columbella,  556 
Columbellaria,  553 
Collumbellina,  553 
Columbites,  640 
Columnaria,  87 
Columnastraea,  101 
Columnopora,  114 
Colus,  559 
Colymmatina,  55 
Connarocystites,  151 
Comastrocrinus,  234 
Comatulina,  237 
Comatulithes,  237 
Comaturella,  237 
Combophyllura,  82 
Comelicania,  418 
Cominella,  556 
Comoseris,  104 
Composita,  418 
Composocrinus,  194 
Compressidens,  509 
Compsoinetra,  237 
Coniptonia,  250 
Conactaeon,  566 
Conchicolites,  139 
Conchidium,  394 
Conchocele,  487 
Gonchodon,  453 
Concbolepas,  558 
Conchopeltis,  520 
Condylocrinus,  189 
Condylopyge,  710 
Confiisastrea,  101 
Congeria,  463 
Conocardium,  446 
Conoceras,  597 
Conoclypeus,  284 
Conocoryphe,  713 
Conocrinus,  229 
Conolampas,  291 
Conorbis,  564 
Conoteuthis,  684 
Cönotreta,  376 
Conotuligera,  321 
Conradella,  522 
Conradia,  373 
Constellaria,  334 
Conularia,  572 
Conulus,  284 
Convexastrea,  101 
Cophinoceras,  603 
Coptostyllus,  548 
Coralliochama,  480 
Coralliophaga,  472 
Coralliuin,  76,  110 
Coraster,  296 
Corbicella,  487 
Corbicula,  474 
Corbis,  486,  486 
Corbnla,  499 
Corbulamella,  499 
Corbnloniya,  499 
Corburella,  470 
Cordillerites,  633 
Cordylocrinus,  199 
Corimya,  467 
Coineöcyclas,  475  ' 
Cormicaprina,  479 
Cornulites,  139 
Comuspira,  37 
Coroniceras,  655 
Coronida,  768 
Coronocrinus,  191 
Coronula,  747 
Corydocephalus,  721 
Corylocrinus,  153 
Corymhocrinus,  190 
Corymbopora,  321 
Corynella,  70 
Corynotrypa,  319 
Coscinella,  345 


Coscinium,  346 
Coscinopora,  64 
Coscinotrypa,  346 
Cosmiolithes,  112 
Cosmoceras,  668 
Cosmocrinus,  221 
Cosmogyria,  658 
Costidiscus,  653 
Cottaldia,  277 
Cotylecrinus,  241 
Cotyiederma,  241 
Cotyledonocrinus,  201 
Cranaena,  403 
Crangopsis,  757 
Crania,  378 
Craniella,  378 
Craniops,  379 
Craniscus,  379 
Craspedites,  664 
Craspedochiton,  513 
Craspedophyllum,  85 
Craspedopoma,  540 
Craspedosoma,  792 
Craspedostoma,  529 
Crassatella,  474 
Crassatellina,  474 
Crassatellites,  474 
Crassina,  472 
Crassinella,  472,  474 
Craterella,  54 
Craterina,  150 
Craticularia,  63 
Cremacrinus,  213 
Crenatula,  447 
Crenella,  468 
Creniceras,  658 
Crenipecten,  457 
Crepidophyllum,  85 
Crepidula,  542 
Crepipora,  328 
Crescentilla,  754 
Crescis,  326 
Creseis,  570 
Creusia,  747 
Cribrilina,  350 
Cribroblastus,  171 
Cribrostomum,  29 
Cricopora,  820 
Crinocystis,  160 
Crioceras,  670 
Crisia,  318,  570 
Crisidia,  318 
Crisina,  320 
Cristellaria,  30 
Cromus,  723 
Cromyocrimis,  224 
Cronicns,  809 
Crossopodia,  141 
Crossostoma,  529 
Crotalocephalus,  724 
Crotalocrinus,  216 
Crucibulum,  542 
Cruratula,  407 
Cryphaeus,  726 
Cryptabacia,  102 
Cryptacanthia,  402 
Cryptaenia,  524 
Cryptangia,  98 
Cryptaulax,  549 
Cryptaxis,  108 
Cryptoblastus,  172 
Cryptocaris,  754 
Cryptoceras,  605 
Cryptochiton,  513 
Cryptochorda,  562 
Cryptoclymenia,  628 
Cryptocoelia,  71 
Cryptocoenia,  101 
Cryptoconus,  563 
Cryptocrinus,  157 
Cryptodictya,  61 
Cryptodon,"  487 
Cryptoglena,  825 
Cryptolithus,  711 
Cryptomya,  499 
Cryptonella,  402 


INDEX 


827 


Cryptoplax,  512,  513 
Cryptoplocus,  549 
Cryptopora,  4(X> 
Cryptoporus,  400 
Cryptoschisma,  169 
Cryptozoe,  751 
Crystallocystis,  152 
Crytopora,  341 
Ctenobolbina,  738 
Ctenocephalus,  713 
Ctenoceras,  599 
Ctcnocrinns,  190 
Cteuodonta,  440 
Ctenopterus,  784 
Ctenostreon,  460 
Cuccoceras,  648 
Cucullaea,  442 
Cucullaria,  442 
Cucullella,  440 
Culicocrinus,  199 
Cultellus,  496 
Cumingia,  495 
Cuinulipora,  351 
Cnpellaecrinus,  199 
Cuphoselenus,  551 
Cupressocrinus,  210 
Cupularia,  351 
Cupulocrinus,  215 
Curculioides,  789 
Cuixuliopsis,  805 
Curticia,  371 
Curtonotus,  472 
Cuspidaria,  469 
Cuvieriiia,  571 
Cyatliaxonia,  81 
Cyatliidium,  241 
Cyathocrinus,  220,  221 
Cyathocystis,  159 
Cyathodonta,  467 
Cyathophora,  101 
Cyathophycus,  61 
Cyathophyllum,  84 
Cyathoseris,  102 
Cybele,  724 
Cyclas,  472,  475 
Cyclaster,  297 
Cyclidia,  533 
Cydina,  492 
Cycloceras,  599,  660 
Cycloclymenia,  628 
Cydocoelia,  381 
Cycloconcha,  470 
Cyclocrinus,  72,  160,  232 
Cyclocystoides,  159 
Cyclolites,  103 
Cyclolituites,  601 
Cyclolobus,  642 
Cydomops,  552 
Cyclonema,  530 
Cyclonssa,  557 
Cyclophorus,  540 
Cyclophthalanius,  788 
Cyclophyllum,  86 
Cyclopora,  347 
Cycloporella,  347 
Cycloporidiiim,  121 
Cydojiorina,  341 
Cyclorhina,  397 
Cyclospliaei'onia,  758 
Cyclospira,  410 
Cyclostoina,  540 
Cyclostomiceras,  611 
Cyclostreina,  532 
Cyclotliyris,  398 
Cyclotrypa,  329 
Cyclotus,  540 
Cydus,  372,  773 
Cylichna,  568 
Cylicocrinus,  195 
Cylindra,  560 
Cyliiidrites,  566 
Cylindrobullina,  560 
Cylindromitra,  560 
Cylindrophyma,  56 
Cyllene,  557 
Cymaceras,  658 


Cymaclyinenia,  628 
Cyniatoceras,  607 
Cymatocliiton,  512 
Cymatophlebia,  810 
Cymbites,  657 
Cymbiutn,  561 
Cymbopliora,  498 
Cyviella,  469 
Cymia,  558 
Cynodonta,  560 
Cypellia,  64 
Cypellocrinus,  199 
Cyphaspis,  721 
Cyphocrinus,  187 
Cyphon,  805 
Cyphosoiiia,  280 
Cyphotrypa,  334 
Cypraea,  553 
Cyprella,  741 
Cypresis,  741 
Cypricardia,  472 
Cypricardinia,  471 
Cypricardites,  442 
Cypridea,  740 
Cypridella,  741 
Cypridellina,  741 
Cypridina,  741 
Cypridinella,  741 
Cyprimeria,  492 
Cyprina,  472 
Cypris,  740 
Cyprosina,  741 
Cyrena,  474 
Cyrenella,  487 
Cyreuoida,  487 
Cyricardella,  471 
Cyrtactinoceras,  609 
Cyrtendoceras,  596 
Cyrtia,  412 
Cyrtidocrinus,  203 
Cyrtina,  412 
Cyrtocalpis,  44 
Cyrtoceras,  611 
Cyrtocerina,  597 
Cyrtochilus,  654 
Cyrtoclymenia,  628 
Cyrtocrinus,  240 
Cyrtodonta,  442 
Cyrtodontopsis,  445 
Cyrtolites,  521 
Cyrtolitina,  521 
Cyrtopinna,  446 
Cyrtopleurites,  648 
Cyrtopora,  322 
Cyrtorizoceras,  610 
Cyrtotheca,  413 
Cyrtulus,  559 
Cystaster,  159 
Cystechinus,  294 
Cystiphyllum,  87 
Cystispongia,  68 
Cystocidaris,  299 
Cystodictya,  346 
Cythere,  739 
CytJierea,  493 
Cythereis,  739 
Cytherella,  740 
Cytherellina,  740 
Cytheridea,  739 
Cytherideis,  739 
Cytherodon,  440 
Cytheropteron,  739 
Cytinopsis,  413 
Cytis,  323 
Cytocrimis,  190 
Cytodaria,  500 
Cytograptus,  132 

Dactylioceras,  662 
Dactylocrinus,  205 
nadylorystin,  156 
DadyloU'.utMs,  682 
Dadyhis,  565 
Dadocrimis,  232 
Daedalus,  141 
Dalila,  439 


Dallina,  406 

Dabnanella,  382 

Dalnianites,  726 

Dalmanitina,  726 

Dalmatites,  64« 

Danilia,  532 

Danubites,  647 

Daonella,  448 

Daphnella,  564 

Daphnites,  648 

Daraelites,  633 

Darellia,  658 

Dasyceras,  652 

Davidaonella,  372,  389 

Davidsonia,  385 

Daviesiella,  389 

Davila,  498 

Davousti,  452 

Dawsonoceras,  599 

Dayia,  409 

Dazieduszyclia,  410 

Deacanemos,  237 

Dearbornia,  376 

Decadocrinus,  223 

Decadopeden,  457 

Defranciopora,  326 

Deiphon,  725 

Deiroceras,  609 

Dejanira,  534 

Dekayella,  333 

Dekayia,  333 

Delgadella,  372 

Delphinula,  529 

Delphinulopsis,  534 

Deltacrinus,  213 

Delthyridea,  406 

Delthyris,  408 

Delthyris,  411 

Deltoceras,  600 

Deltocyathus,  95 

Democrinus,  229 

Denckmannia,  660 

Dendracis,  108 

Dendraster,  288 

Dendricopora,  342 

Dendrocrinus,  215 

Dendrocystites,  151 

Dendrograptus,  128 

Dendrophyllia,  106 

Dendropupa,  576 

Dendrostrea,  450 

Denkmannia,  401 

Dentalina,  30 

Dentalium,  509 

Deocrinus,  188 

Derbya,  386 

Derniatomya,  469 

Dertnatopora,  349 

Deroceras,  662 

Deshayesia,  543 

Desmidocrinus,  194 

Desmoceras,  667 

Desmograptns,  128 

Desoria,  296 

Detocrinus,  225 

Deutocystites,  150 

Diabolocrinus,  188 
i  J)ia(ievui,  277 

Diadiploceras,  605 

Diamenocrinus,  189 
!  Diamesopora,  347 

Diannlites,  335 
[  Diaphana,  568 

Diaphorites,  662 

Diaphorostoma,  541 

Diaphragnms,  390 

Diapora,  123 

Diastema,  537 

Diastopora,  319,  319,  320 

Diastoporina,  320 

Dicaniara,  416 

Dicollogi-aptiis,  130 

Diceras,  477 

Dicerocardium,  454 

Dichocrinus,  201 

Dichograptus  129 


Dicliotrypa,  346 
Dicoelosia,  383 
Dicranella,  738 
Dicraniscus,  387 
DicranograptuH,  130 
Dicranopora,  345 
Dicranurus,  722 
Dicroloma,  551 
Dictyoceras,  599 
Dictyoconites,  680 
Didyocrinites,  72 
Dictyocrinus,  72,  160 
Dictyograptus,  128 
Dictyomitra,  44 
Dictyonella,  396 
Dictyonenia,  128 
Dictyopleurus,  282 
Dictyospongia,  60 
Dictyothyris,  404 
Didacna,  490 
Didynntes,  642 
Didymograptus,  129 
Didymopora,  329 
Dielasma,  402 
Dielasmina,  403 
Dielasmoides,  403 
Diempterus,  551 
Digitari,  472 
Dignomia,  374 
Digonioceras,  607 
Dikelocephalina,  720 
Dikelocephalus,  720 
Dilobella,  738 
Dimerella,  399 
Dimerocrinus,  187,  205 
Dimorion,  612 
Dimorpharaea,  103 
Dimorphastrea,  104 
Dimorphina,  31 
Dimorphites,  639 
Dimorphoceras,  637 
Dimorphocrinus,  169 
Dimorphograptus,  132 
Dimorphosoma,  551 
Dimya,  459 
Dimyodon,  459 
Dinarella,  401 
Dinarites,  648 
Dineura,  806 
Dinobilus,  373 
Dinocystis,  159 
Dinopilio,  791 
Dinoplax,  513 
Dinorthis,  382 
Diodoceras,  607 
Dionide,  711 
Dionites,  648 
Dioristella,  416 
Diorugoceras,  604 
Diphragmoceras,  595 
Diphyites,  403 
Diphyphyllum,  84 
Dipilidia,  478,  482 
Diplacomoceras,  671 
Diplagnostus,  710 
Dipleura,  724 
Diplocenis,  595 
Diplocidaris,  274 
Diploclema,  321 
Diploconus,  683 
Diplocraterion,  141 
Diplocrinus,  233 
Diplocteninm,  100 
Diplodonia,  487 
Diploepora,  112 
Diplograptus,  130 
Diplomoceras,  654 
Diplopodia,  277 
THplopKwa,  342 
Diploporaria,  342 
Diploria,  99 
Diplosirenites,  648 
Diplospirelhi,  418 
üiplostoina,  71 
Diplotheca,  571 
Diplotrypa,  338 


828 


TEXT -BOOK  OF  PALE0NT0L0C4Y 


Dipterocuris,  754 
Diptvcliocci-as,  (yh'.i 
Disciiidi's,  rüO 
Disciiia,  ;i7S 
Disciiiiscii,  378 
Disciiiocaris,  754 
Discinolepis,  376 
Discinopsis,  377 
Ducites,  604 
Discitocems,  604 
Discocavea,  325 
Discoceras,  600,  655, 
Discoclynienia,  628 
Discocyathus,  95 
Discocystis,  159 
Discocytis,  323 
DisccKlermia,  55 
Di.scofacigera,  321 
Discohelix,  527 
Discoidea,  283 
Discophyllites,  651 
Discorbina,  32 
Discors,  490 
Discoscapliites,  670 
Discosuinis,  609 
Discosparsa,  319 
Discotarbus,  791 
Discotrochus,  94 
Discotropites,  638 
Discotypa,  337 
Disculiiia,  404 
I)isjectx)pora,  124 
Distichites,  648 
Distichoceras,  659 
Distortrix,  555 
Ditaxia,  325 
Dithyrocaris,  753 
Ditremaria,  525 
Ditretus,  549 
Dittniarites,  648 
Dittopora,  339 
Di  Varicella,  486 
Dizygocrinns,  196 
Dochinostoma,  290 
Dolatocrinus,  191 
Dolichocrinus,  229 
Dolichopteron,  444 
Dolichopterus,  783 
Dolium,  555 
Domatoceras,  606 
Donacicardium,  484,  ■ 
Donax,  496 
Dorateuthis,  688 
Dorsetensia,  660 
Dorycrinus,  196 
Dorydenna,  57 
Dosinia,  492 
Douvilleia,  566 
Douvilleiceras,  669 
Douvillina,  385 
Dreissenia,  463 
Dreissensiomya,  463 
Drepaiiella,  738 
Drepanites,  648 
Drepanopterus,  784 
Urillia,  563 
Droinia,  765 
Dryinadusa,  799 
DryvMtryjKi,  340 
üualina,  439 
Dumortieria,  657 
Duiicanella,  82 
Durga,  454 
Dux,  438 
Dylmvskielld,  329 
TJyeria,  530 
Dysagrion,  811 
Uysaster,  292 
Dyscolia,  404 
Dystack'lla,  438 

Eastonia,  498 
Eatonia,  397 
Kburna,  556 
Eccylioiiiphalus,  527 


Eccyliopterus,  527 
Echiiiarachnius,  2SS 
Bcliinaster,  252 
Ecliinasterella,  251 
Kchinohrissus,  289 
Echinocardium,  297 
Echinocaris,  751 
Echinochama,  478 
Echinocorys,  292 
Ecliinocrei)is,  298 
Echinocyamus,  286 
Echinocyphns,  282 
Echinocystites,  157,  299 
Echinodiscus,  288 
Echinoencrinus,  154 
Echinognathus,  783 
Echinolampas,  291 
Echinometra,  283 
Echinoneus,  289 
Echinopsis,  276 
Kchinospatagus,  294 
Echinosphaerites,  152 
Echinostrephus,  282 
Echinothuria,  278 
Echinus,  281 
Ectenocrinus,  212 
Ectenodesvm,  444 
Ectolcites,  648 
Ectomaria,  525 
Edaplioceras,  C07 
Edeiitula,  447 
Edmondia,  439 
Edrioaster,  159 
Edriocrinus.  206 
Edwardsocrinus,  199 
Egeria,  496. 
Egeta,  474 
Ehrenbergina,  29 
Eichwaldia,  396,  396 
Eileticus,  793 
Elaeacrinus,  171 
Elasmostoma,  71 
Elcana,  798 
Eider,  761 
Eldonia,  313 
Elea,  324 

Eleutherocaris,  752 
Eleutherocrania,  379 
Eleutherocrinus,  170 
Eligmus,  451 
Elkania,  372 
Ellipsactinia,  120 
Ellipsocaris,  754 
BUipsocephalus,  717 
Ellipsoidina,  29 
Elliptocephala,  714 
Elpe,  741 
Elymella,  439 
Elymocaris,  752 
Emarginula,  526 
Embla,  469 
Embolus,  570 
Emeraldella,  776 
Emileia,  663 
Emmelezoe,  752 
Emmonsia,  114 
Emperoceras,  654 
Enallhelia,  95 
Enallocrinus,  216 
Enantiosphen,  400 
Enclimatoceras,  603 
Encoiloceras,  606 
Encope,  288 
Encrinurus,  723 
Encrinus,  225,  233 
Endoceras,  595 
Kndolohus,  605 
Endothyra,  33 
Bndoxocrinus,  233 
Engonoceras,  671 
Enicliaster,  294 
Ennalaster,  294 
Ennmcystis,  153 
Enopleura,  150 
Enoplocera.s,  606 
Enoplochiton,  513 


Enoploclytia,  763 
Eiisis,  496 
Entalina,  510 
Entdliopsis,  509 
Entalis,  509 
Entalium,  508 
Entalophora,  230 
Enteletes,  383 
Enteletoides,  383 
Entodesma,  468 
Entolium,  458 
Bntomidella,  741 
Entomis,  741 
EntoMocaris,  7ö0 
Eiitomoconchus,  742 
Eobuthus,  788 
Eocicada,  815 
Eocidaris,  300 
Eocyclina,  492 
Eocystites,  151 
Bodiadenia,  276 
Eodiscus,  711 
Eoharpes,  711 
Eoluidia,  255 
Eooholus,  372 
Boorthis,  381 
Eophrynus,  791 
Eophyton,  134 
Eopteria,  439,  733 
Eoscorpius,  788 
Eosphaeroma,  758 
Eospirifer,  411 
Eostrophomena,  384 
Botrochus,  543 
Eotrophonia,  137 
Bozoon,  37 
Epactocrinus,  219 
Ephemera,  809 
Ephippioceras,  604 
Ephippium,  461 
Ephippodonta,  488 
Epiaster,  294 
Epicyrta,  4Ü7 
Episageceras,  633 
Episiphon,  509 
Epismilia,  97 
Epithyris,  402,  403 
Epitonium,  538 
Erato,  554 
Eremites,  648 
Eremoceras,  611 
Eretmocrinus,  195 
Erettopterus,  785 
Erichthus,  769 
Eridophyllum,  84 
Eridorthis,  381 
Eridotrypa,  329,  335 
Ennocystis,  155 
Eriphyla,  472 
Eriptycha,  567 
Brisocrinus,  225 
Erodona,  499 
Brvilia,  498 
Erycina,  488 
Erycinella,  488 
Eryma,  763 
Eryon,  762 
Eryx,  498 
Esoasona,  735 
Eschara,  350 
Esclmrites,  324 
Escharopora,  345 
Estheria,  734 
Estheriella,  734 
Esthoniopora,  336 
Estonioceras,  607 
Etallonia,  566,  703 
Etheria,  455 
Etheridgaster,  251 
Etheridgia,  68 
Etheridgina,  391 
Ethviophyllum,  105 
Etisus,  767 
Etyns,  767 
Bubleptus,  796 
Eucaenus,  801 


I  Bucalathis,  404 
Eucalytocrinus,  192 
Eucluirii^,  469 
Eucluisma,  439,  733 
Euchilotheca,  571 
Eiichirocrinns,  213 
Euclirysalis,  538 
Euciroa,  469 
Eucladia,  255 
Eiicladocrinus,  200 
Euconactaeon,  566 
Euconia,  525 
Eucorystes,  765 
Eucratea,  348 
Encrinus,  187 
Eucuclodema,  381 
Eucydus,  530 
Eucymba,  561 
Eucyiditium,  44 
Encystis,  155 
Eiicythara,  564 
Eudea,  69 
Budesella,  388 
Budesia,  406 
Budesicrinus,  241 
Eudoxocliiton,  513 
Bugeniacrinus,  239 
Eugereon,  817 
Bugyrina,  55 
Bulielia,  95 
Bulimella,  537 
Euloma,  715 
Eulophoceras,  672 
Eumegalodon,  454 
Eumetria,  414 
Eumicrotis,  448 
Eunella,  402 
Eunema,  530 
Bunicites,  139 
Bunoa,  377 
Euubolus,  871 
Euomphalopterus,  527 
Buomphalus,  527 
Bupachycrinus,  224 
Eupatagus,  297 
Eupera,  475 
Buplienius,  523 
Euphoberia,  798 
Buphyllites,  652 
Euproöps,  774 
Eupsaininia,  105 
Euractinella,  418 
Euraphia,  747 
Burhodia,  290 
Euryale,  255 
Burycare,  715 
Eurychilina,  738 
Burydictya,  345 
Burymya,  462 
Burynoticeras,  667 
Buryocrinus,  205 
Burypneustes,  282 
Burypterella,  783 
Eurypterus,  782 
Eurysoma,  783 
Burystomites,  600 
Busarcus,  783 
Eusiphonella,  70 
Euspilopora,  345 
Buspira,  543 
Buspirocrinus,  218 
Eustoma,  550 
Bustylus,  537 
Eutaxocrinus,  205 
Eutermes,  804 
Buthemon,  255 
Buthria,  557 
Eutliydesma,  439 
Exdhyris,  417 
Eutonioceras,  646 
Eutrephoceras,  607 
Butiocbocrinus,  196 
Euzonus,  792 
Evactinopora,  346 
Exapinurus,  777 
Exelissa,  549 


INDEX 


829 


Exogyra,  450 
Kxtnwrinus,  232 

Fcabella,  488 
Fabulariu,  3!' 
Falcilituites,  60(» 
Ftihmla,  r»08 
Faorina,  2ltO 
Fasciciilipora,  321 
Fascinella,  543 
Fasciolaria,  559 
Fascipora,  321 
Fasciporina,  821 
Faunus,  548 
Favia,  98 
Favicella,  330 
Favistella,  87 
Favositella,  328 
Favosites,  113 
Felania,  487 
Fenestella,  341 
Fenestralia,  341 
Feiiestrapora,  341 
Fenestrella,  341 
Fergensia,  320 
Fibula,  549 
Fibularia,  287 
Ficula,  555 
Fieldia,  750 
Filicea,  323 
Filier  isla,  318 
Filicrisina,  320 
Filifascigera,  322 
Filisparsa,  319 
Fiinbria,  486 
Fimbriella,  487 
Fimbriothyris,  407 
Finkelnburgia,  381 
Fincherid,  474 
Fissidentaliuin,  509 
Fissirostra,  406 
Fissurella,  526,  526 
Fissurellidea,  526 
Fissuridea,  526 
Fissur  irostra,  406 
Fistulana,  500 
Fistulipora,  329 
Flahi'Uocrinus,  225 
Flahfllothvris,  406 

Flabellum,  94,  570 

Fleniingia,  531 

Flemingites,  645 

Foordiceras,  005 

Floridina,  351 

Fl.ustrelluria,  350,  351 

Forbesia,  545 

Forbesiceras,  671 

Forbesioerinus,    204, 
205 

Fordilla,  439 

Fordinia,  371 

Forficula,  800 

Foricula,  324 

Fortisia,  567 

FoRsariofsis,  534 

Fossarulus,  545 

Fossarns,  540 

Fragilia,  494 

Fragum,  490 

Frenuhi,  406 

Frenulina,  406 

Frieleia,  400 

Froiidi(nilaria,  30 

Fulgoraria,  5(51 

Fulgoridmm,  819 

Fulgur,  557 

Fungia,  102 

Fungocystites,  156 

Fuselia,  410 

Fusinus,  559 

Fusisi)ira,  538 

Fustiaria,  509 

Fusulina,  34 

Fusus,  559 

Gadila,  510 


Gadinia,  573 
dadns,  510 
Gafrariuni,  493 
Gtüaten,  474 
Galathea,  7<'i4 
Galaxea,  100 
Galenopsis,  766 
Galeoda,  554 
Galeonnna,  488 
Galerites,  284 
Galeropygus,  285 
Galerus,  542 
Gainmarocrinus,  240 
Gainmarus,  759 
Gamophura,  570 
Gampsonyx,  756 
Ganymeda,  237 
Garantiana,  664 
Gargantua,  351 
Garnieria,  672 
Gasocaris,  756 
Gaspesi,  385 
Gasterocoma,  219 
Gastrana,  494 
Gastrioceras,  636 
Gastrochaena,  500 
Gastrocrinus,  221 
Gaiidryceras,  652 
Gaudryina,  29     • 
Gazacrinus,  187 
Gecarcinus,  767 
Geinitzella,  335 
Geinitzia,  803 
Geisonoceras,  598 
Geniellaria,  348 
Genuna,  494 
(jemviellana,  479 
Gemniellaroia,  392 
Gemmipora,  108 
Genabacia,  103 
Genea,  557 
Genicopatagus,  297 
Gennaeacrinus,  195 
Genota,  563 
Geocoma,  237,.  256 
Geocrinus,  194 
Geophilus,  793,  139 
Geoteuthis,  687 
Gephyroceras,  631 
Gephyrocrinus,  238 
Geralinura,  788 
Geraphrynus,  791 
Geratarbus,  791 
Geroneura,  797 
Gervillia,  447 

Geyerella,  387 

Geyero(;eras,  652 

Gibbula,  532 

Gigantoceras,  608 

Gilbertsocrinus,  188 

Girtyella,  403 

Gisortia,  554 

Gissocrinus,  220 

Glaharis,  455 

Gladiograptus,  132 

Glandulina,  30 

Glaphurus,  723 

Glaphyrocystis,  155 

Glassia,  409 

Glassina,  415 

Glaucomya,  494 

Glauconiyacidae,  494 

Glauconia,  546 

Glaueonome,  342,  343 

Glenotremites,  237 

Globigerina,  31 

Glohoblastus,  171 

Gloria,  439 

Glossina,  374 

Glossites,  439 

Glossoceras,  597 

Glossograptus,  130 

Glossothyris,  404 

Glossotrypa,  330 

Glottidia,  374 

Glycimeris,  443,  499,  500 


Glyphaea,  762 
Glyphidites,  648 
Glyphioceras,  636 
Glyphis,  526 
Glyphocypluis,  282 
Glyphostonia,  564 
Glyptaster,  187 
Glyptechinus,  282 
Glypticus,  276 
Glyptobasis,  531 
Glyptocardia,  439 
Glyptocidaris,  280 
Glyptocrinus,  189 
Glyptocystites,  154 
Glyptodesma,  444 
Glyptograptus,  130 
Glyptopora,  346 
Glyptosceptron,  110 
Glyptoscorpius,  785 
Glyptosphaerites,  156 
Gnathia,  758 
Gnathodon,  498 
Gnoriinocrinus,  205 
Goldius,  720 
Gomphoceras,  613 
Gomphocystites,  156 
Gomphoides,  810 
Gonambonites,  392 
Gongylospongia,  60 
Goniacrinus,  218 
Goniasteroidocrinus,  188 
Goniastrea,  99 
Goniobasis,  548 
Gonioceras,  609 
Goniocidaris,  273 
Goniocladia,  346 
Gonioclymenia,  628 
Goniocoelia,  416 
Goniocora,  97 
Goniodiscus,  711 
Gonioloboceras,  631 
Goniomya,  466 
Goniophora,  462 

Gouiophorus,  279 

Goniophylluni,  87 

Goniopygus,  276 

Goniosoma,  472 

Gonioteuthis,  682 

Goniotrypa,  345 

Gonocrinites,  154 

Gonodactylus,  768 

Gonodon,  486 

Goodallia,  472 

Gorgonella,  110 

Gorgonia,  110 

Gorgonoceplmlus,  255 

Gosavia,  561 

Gosseletia,  445 

Gosseletina,  524 

Gothocrinus,  215 

Gothograptus,  132 

Gotlandia,  373 

Gouldia,  474,  493 

Graeophonus,  788 

Grammatodon,  441 

Grammoceras,  658 

Grammysia,  439 

Granatocrinus,  171 

G-raphiocrinus,  222,  225 

Graphoceras,  658 

Graphularia,  110 

Graptacnie,  509 

Graptodictya,  345 

Grasia,  292 

Grateloupia,  492 

Greenfieldia,  415 

Gresslya,  464 

Griesbachites,  639 

Gripliodictya,  61 

Grossouvria,  663 

Grotriania,  472 

Gruenewaldtia,  409 

Gryllus,  799 

Gryphaea,  450 

Gryphaeostrfa,  450 

Gryphochiton,  512 


Grypoceras,  602 
Gualtieria,  297 
Guembelites,  648 
Guerangeria,  452 
Guettardia,  64 
Guettardicrinus,  232 
Guilfordia,  528 
Gundlacliia,  575  • 
Gwynia,  405 
Gymnites,  645 
Gynniocrinus,  240 
Gyninotoceras,  647 
Gypidia,  394 
Gypidula,  395 
Gyronema,  530 
Gyropleura,  478 

Habelia,  776 
Habrocrinus,  194 
Hadentomum,  806 
Hadrocrinus,  191 
Hadrophylluui,  82 
Haenleinia,  447 
Hagenowinella,  349 
Halia,  561 
Halicardia,  468 
Halilucites,  646 
Haliotis,  523 
Haiiris,  469 
Hallicystis,  154 
Halliella,  738 
Hallina,  408 
Hallirhoa,  54 
Halloceras,  603 
Hallodictya,  61 
Hallopora,  337 
Halloporina,  337 
Halobia,  448 
Halomitra,  102 
Halonynipha,  470 
Halorella,  399 
Halorites,  639 
Halysiocrinus,  214 
Halysites,  117 
Haniinea,  567 
Hamites,  653 
Hammatoceras,  660 
Hamulina,  654 
Hamulus,  508 
Hamusina,  531 
Hanleya,  512 
Hapalocrinus,  199 
Hapaloptera,  807 
Haplaraea,  105 
Haploceras,  661 
Haplocorius,  721 
Haplocrinus,  208 
Haplocystis,  159 
Haplohelia,  95 
Haplooecia,  321,  324 
Haplo-phragmium,  26 
Haplopleuroceras,  660 
Haploscapha,  447 
Haplosmilia,  101 
Haplostiche,  26 
Harmocrinus,  189 
Harpa,  562 

Harpactocarcinus,  767 
Harpagodes,  552 
Harpax,  459 
Harpeä,  711 
Harpina,  711 
Harpopsis,  562 
Harpoceras,  658 
Harttina,  402 
Hastlniinia,  785 
Hastula,  562 
Hauericeras,  667, 
Hauerina,  38 
Hauerites,  635 
Haugia,  060 
Haustellum,  558 
Hautkenia,  547 
Hebertella,  381 
Hedenstroeniia,  634 
Hederella,  320 


830 

iiriviu'.i,  vtn 

HrU-lnll,  :VJO 
Helcioiiiscus,  '>-H) 
Helcionopsis,  5'20 
HelianthasttT,  'Jöl 
Heliasttn-,  251 
Helicanlax,  551 
Helicoceras,  (554 
Helicodictya,  GO 
Helicodonta,  576 
Helicophanta,  576 
Helicopora,  341 
Helicoryptus,  532 
Helicotonia,  527 
Helictites,  648 
Heliocrinus,  152 
Heliolites,  112 
Heliophyllum,  84 
Heliopora,  111 
Heliotrypa,  345 
Helix,  576 
Helmersenia,  372 
Helminthochiton,  512 
Heloceras,  599 
Heionyx,  510 
Helopora,  342 
Hemiarthrum,  512 
Hemiaspis,  777 
Hemiaster,  295 
Hemicardium,  444 
Hemicellaria,  324 
Hemicidaris,  275 
Heniicosmites,  152 
Hemicrinus,  240 
Hemicystites,  159 
Hemidiaderaa,  275 
Hemidonax,  484,  496 
Hemifusus,  557 
Hemigyraspis,  719 
Hemimactra,  498 
Heminajas,  452 
Hemipatagus.  294 
Heniipedina,  277 
Heinlphragma,  338 
Hemiphragmoceras,  612 
Hemiplethorhynchus,  39 
Hemiplicatula,  461 
Hemipneustes,  293 
Hemipronites,  393 
Heraiptychina,  403 
Heraisinus,  548 
Hemithyris,  399 
Hemitrypa,  341 
Hejikulactylus,  552 
Heptastyiis,  106 
Heraclites,  648 
Hercoceras,  605 
Hercocrinus,  188 
Hercoglossa,  603 
Hercynella,  573 
Hermatostroma,  123 
Hernodia,  320 
Herpetocrinus,  212 
Herpetolitha,  102 
Hertha,  237 
Hesperagrion,  811 
Hesperiella,  524 
Hesperites,  648 
Heteraster,  294 
Heterastridiuin,  2,  121 
Heterelasma,  403 
Heteroblastus,  172 
Heterocanlia,  498 
Heterocentrotus,  283 
Hetcroceras,"  654 
Heterocrinus,  212,  212 
Heterocystites,  153 
Heterodiadema,  277 
Heterwlicerds,  477 
Heterodictya,  344 
Heterodoiiax,  495 
Heteroncnia,  318 
Heterophyllia,  87 
Heteropora,  326 
Hoterosalt'iia,  21\> 
Heteroschisiiia,  168,  509 


TEXT -BOOK  OF  PALEONTOLOGY 


TIcterostegina,  35 
Heterotypa,  333 
Hdtangia,  484 
Hexacrinus,  200 
Hexagonella,  330 
Hexalwcystis,  152 
Hexameroceras,  612 
Hiatella,  499 
Hibemula,  237 
Hibolithes,  682 
Hildoceras,  658 
Himantopterus,  783 
Hindella,  415 
Hilldia,  56 
Hindsiella,  488 
Hinnites,  458. 
Hippagus,  469 
Hipparionyx,  386 
Hippochrenes,  552 
Hipponichariou,  735 
Hippoiüx,  542 
Hippopodium,  462 
Hippoporina,  352 
Hippopus,  490 
Hippurites,  482 
Histioderma,  141 
Histricrinus,  200 
Hochstetteria,  449 
Hodotermes,  804 
Hoemesia,  447 
Holaster,  293 
Holasterella,  62 
Holcodiscus,  667 
Holcospongia,  71 
Holcostephamis,  664 
Holectypus,  284 
HoUandites,  647 
Hollina,  738 
Holmia,  714 
Holmiceras,  601 
Holocrinus,  232 
Holocystis,  101, 150 
Hologyra,  533 
Holopea,  530,  539 
Holopella,  538 
Holopneustes,  282 
Holopus,  241 
Holorhynchus,  395 
Holothuria,  313 
Homaloceras,  601 
Homalocrinus,  203 
Homalonotus,  724 
Homarus,  764   . 
Homelys,  761    ; 
HoDierites,  639 
Homocrinus,  217 
Homocystites,  154 
Homoeosolen,  323 
Homoeospira,  414 
Homolampas,  297 
Homomya,  466 
Homotrypa,  332 
Homotrypella,  332 
Hoplites,  668 
Hoplitoides,  671 
Hoplocrinus,  211 
Hoplolichas,  722 
Hoploinytilus,  449 
Hoploparia,  764 
Horioceras,  659 
Horiostoina,  541 
Hormotoma,  525 
Hornera,  324 
Huddlestonia,  658 
Huenella,  392 
Hiighmillcria,  785 
Hiui;4antcs,  MG 
Hurdia,  750 
Huronia,  609 
Hustedia,  414 
Hyalaea,  570 
Hyalostelia,  62 
Hyalotragos,  58 
Hyattechiiius,  301 
llyatfclht,  415 
Uyattidiiia,  415 


Hyboclypeus,  292 
Hybocrinus,  211 
Hybocystis,  211 
Hybocystites,  154 
Hyboechinus,  306 
Hydatina,  567 
Hydnoceras,  60 
Hydractinia,  120   . 
Hydreiouocrinns,  223 
Hydriocrinus,  222 
Hydriodictya,  60 
Hydrobia,  545 
Hymenocarls,  750 
Hymenocydus,  36 
Hyiuenophyllia,  99 
Hynniphoria,  407 
Hyocrinus,  238 
Hyolithellus,  572 
Hyolithes,  571 
Hypagnostus,  710 
Hypalocrinus,  234 
Hypanthocrinus,  192 
Hypecliinus,  282 
Hyperammina,  25 
Hyperlioceras,  658 
Hyperocrinus,  196 
Hyphautaenia,  61 
Hyphasmopora,  344 
Hypocladiscifes,  643 
Hypocrinus,  157,  219 
Hypodiadeina,  275 
Hyponome,  160 
Hypothyridina,  398 
Hypothyris,  398 
Hypotrema,  461 
Hypsipleura,  537 
Hyptiocrinus,  187 
Hysocrinus,  208 
Hystatoceras,  672 
Hystricurus,  716 

Ichthyocrinus,  204 

Ichthyosarcolites,  480 

Idalina,  39 

Idiocrinus,  187 

Idiostroma,  124 

Idiotrypa,  335 

Idmonea,  320 

Idonearea,  442 

Jgoceros,  541 

Ilariona,  290 

Illaenus,  719 

Illycrinus,  230 

Ilyodes,  793 

Imbricaria,  560 

Indoceras,  671 

Infraclyi^eus,  292 

Infulast(!r,  294 

Inocellia,  812 

Inoceranius,  447 

Fntrapora,  345 

Inversaria,  324 

Inyoites,  646 

[ocrinus,  212 

Iphidea,  370 

Iphidella,  370 

Iphigenia,  496 

Iridina,  455 

Iridometra,  237 

Isanda,  532 

Isaster,  294 

Isastrea,  98 

Iscanotia,  494 

Ischadites,  72 

Ischnochiton,  513 

Iscliyrina,  733 

Ischyrodonta,  442 

Isidora,  575 

Isis,  233 

Ismenia,  405,  408 

Isoarca,  443 

Lsobuthus,  788 
I  Isoeardia,  491 
I  Lsocliilina,  737 

Isocrania,  379 
I  Isocrimis,  206,  233 


Isoculia,  439 
Isodonta,  496 
Isogonomon,  447 
Isogramma,  389 
Isonema,  538 
Isopleiira,  553 
Isorhaphinia,  57 
Isorhynchus,  393 
Isoteius,  719 
Isotrypa,  341 
Isoxys,  735 
Itieria,  549 
Ivania,  524 

Jaculella,  25 
Jaekelocystis,  154 
Jahnites,  670 
Janeia,  438 
Janiceps,  418 
Janira,  457' 
Japonites,  637,  645 
Jerea,  54 
Jereica,  58 
Joannisella,  487 
Joannites,  642 
Jodamia,  482,  482 
Jonesella,  738 
Jonesina,  738 
Jouannetia,  501 
Jovellania,  610' 
Jovites,  639 
Juglandocrinus,  153 
Julopsis,  793 
Julia,  464 
Julus,  792 
Jupiteria,  815 
Juvavella,  401 
Juvavellina,  401 
Juvavites,  639 

Kampecaris,  793 
Kanilla,  565 
Kanopliyllum,  82 
Karpinskya,  409 
Katharina,  513 
Kayserella,  386 
Kayseria,  418 
Keilostoma,  537 
Kelaeno,  688 
Kellia,  488 
Kelliella,  489 
Keramosphaera,  40 
Keyserlingia,  376 
Keyserlingina,  387 
Keyserlingites,  647 
Kingena,  406 
Kingia,  406 
Kionoceras,  600 
Kirkbya,  738 
Klipsteinia,  648 
Kloedenella,  738 
Kloedenia,  738 
Knemiceras,  671 
Kochia,  444 
Koenenites,  631 
Kokenella,  524 
Kokenia,  522 
Koninckella,  419 
Koninckia,  107 
Koninckina,  419 
Koninckites,  645 
Koninckoceras,  606 
Koninckocidaris,  301 
Koninckodonta,  419 
Koninckophyllum,  85 
Kraussia,  408 
Kraussina,  408 
Kreischeria,  791 
Kustarachne,  789 
Kutorgina,  371 
Kymatites,  644 

Labechia,  124 
Labiduromma,  800 
Labiosa,  498 
Lacazella,  366 


I 


INDEX 


831 


Lacazella,  388 
Laatzind,  38 
Lachesis,  5G3 

-5  Lacuna,  540 

f  Lacuiiella,  540 

Lacuiiina,  539 
Laevicardiuni,  490 
Laevidentaliuni,  509 
Lagauum,  286 

r;  Lagena,  29 

I  lAujeniocrinus,  209 

Laguncula,  544 
Lahuseniocrinus,  189 
Lakhmirux,  372 
Lamanskya,  384 
Lambi-QS,  766 
Lampania,  550 
Lampterocrinus,  187 
Lanceolites,  635 
Lanieria,  284 
Lapeirousia,  482 
Lapillocystites,  150 
Lapparentia,  545 
Lapworthura,  255 
Ijaqueus,  406 
Lartetia,  545 
La.saea,  488 
Lasiograptus,  131 
Laternula,  466 
Laterocava,  320 
Laterocea,  323 
Latirus,  559 
Latomeandra,  98 
Latusastrea,  97 
Latzelia,  793 
Laubella,  524 
Leaia,  734 
Leanchoilia,  732 
Lebedictya,  60 
Lecanites,  644 
Lecanocrinus,  203  • 
Lecanocrinus,  205 
Lecythiocrinus,  221 
Lecythocrinus,  221 
Leda,  441 
Leila,  455 
Leiochonia,  59 
Leiocidaris,  273 
Leioderma,  561 
Leiomya,  469 
Leioniyalina,  449 
Leiopedina,  278 
Leiopteria,  448 
Leiorhynchus,  398 
Leiostoma,  559 
Leiostracosia,  67 
Lejopyge,  710 
Lenita,  288 
Lenticeras,  672 
Lenticulites,  35 
Lepadocrinus,  154 
Lepadocystis,  154 
Lepas,  745 
Lepeditta,  734 
Leperditella,  737 
Leperditia,  737 
Lepeta,  520 
Lepetella,  520 
Lepetopsis,  520 
Lepidaster,  251 
Lepidechiuus,  306 
Lepidesthes,  306 
Lepidocentrus,  301 
Lepidocidaris,  300 
Lepidocoleus,  743 
Lepidoderma,  782 
Lepidodistis,  159 
Lepidopleurus,  612 
Lepidolites,  72 
Lepidospongia,  67 
Lepidurus,  733 
Lepisma,  819 
Lepocrinus,  154 
Lepralia,  352 
Leptaster,  250 
Leptaena,  384 


Leptaenalosin,  391 

Leptaenisia,  385 

Leptagonia,  384 

Jjeptastraea,  98 

Leptella,  384 

Leptembolon,  372 

Leptesthes,  474 

Leptobolus,  372 

Leptoceias,  653 

Leptochiton,  512 

Leptocoelia,  417 

Leptocrinus,  194 

Leptodesma,  444 

Leptodomus,  439 

Leptodus,  387 

Leptograptus,  130 

Leptomaria,  524 

Lepton,  488 

Leptophragma,  64 

Leptophyllia,  103 

Leptopoina,  540 

Leptoria,  99 

Leptosolen,  496 

Leptospisula,  498 

Leptostrophia,  385 

Leptoteuthis,  687 

Leptotrypa,  334 

Leptoxis,  548 

Leskia,  297 

Leuconia,  574 

Leucozonia,  560 

Leuctra,  808 

Leuroceras,  604 

LeveiUeia,  524 

Lewisiella,  532 

Libiiina,  472 

Lichas,  721 

Licheiialia,  347     " 

Lichenocrinus,  160 

Lichenocystis,  157 

Lichenoides,  157 

Lichenopora,  325 

Licheuotrypa,  330 

Liebea,  449 

Ligula,  467 

Lillia,  660 

Lima,  460 

Limacine,  570 

Limaea,  460 

Limanomia,  461 

Limatula,  460 
Limnaeus,  574 
Limnocardium,  490 
Liraopsis,  442 
Limoptera,  448 

Limuloides,  777 
Liimilus,  774 
Linearia,  494 
Lindstroemaster,  248 
Lindstroemella,  378 
Lingula,  374 
Lingularius,  374 
Lingulasma,  374 
Lingulelasma,  374 
Lingnlella,  372 
Lingulina,  30 
Lingulipora,  374 
Lingulobolus,  371 
Lingulficaris,  751 
Lingulodiscina,  377 
Lingulops,  374 
Linnarssonella,  377 
Linnarssonia,  376 
Linthia,  296 
Linuparus,  763 
Lioceras,  658 
Lioclema,  336 
Lioclemella,  336 
Liolophura,  513 
Liopeplum,  561 
Liopistlia,  469 
Lioplax,  544 
Liospira,  525 
Liothyrina,  365,  404 
Liothyrift,  404 
Liotia,  529 


Liparoceras,  656,  657 
Lisgocaris,  754 
Lispoceras,  604 
Lispodesthes,  551 
Lissoceras,  661 
Lissochilus,  534 
Lissopleura,  401 
Lithactiiiia,  102 
Lithagrion,  811 
Litharaea,  106 
Lithobius,  793 
Lithocampe,  42 
Lithocardium,  490 
Lithocrinus,  204 
Lithodendron,  99 
Lithodomus,  463 
Lithodryas,  815 
Lithogaster,  762 
Lithoglyphus,  545 
Lithophagus,  463 
Lithophylax,  766 
Lithopoma,  528 
Lithostrotion,  86 
Litiopa,  540 
Litoceras,  600 
Litoricola,  766 
Littorina,  539 
Littorinella,  545 
Lituites,  601 
Lobantale,  509  • 

Lobites,  641 
Lobocarcinus,  767 
Lohocrinus,  196 
Lobolühus,  160,  190 
Lobopora,  353 
Lobopsammia,  106 
Locularia,  322 
Loculipora,  341 
Loczyella,  388 
Lodanella,  150 
Loftusia,  120 
Louchodonias,  712 
Longobardites,  634 
Lonsdaleia,  86 
Lophoblastus,  172 
Lophoceras,  607,  658 
Lophocrinus,  221 
Lopholepis,  322 
Lophonotus,  793 
Lophophyllum,  84 
Lophoseris,  103 
Lophosmilia,  100 
Lophospira,  525 
Lorica,  513 
Loricella,  513 
Loricites,  512 
Loricula,  744 
Loriolaster,  251 
Loripes,  486 
Lotorium,  555 
Lovenechinus,  303 
Lovenia,  297 
Loxoceras,  608 
Loxonema,  536 
Loxopteria,  444 
Lucapina,  526 
Lucapiiiella,  526 
Luciua,  485,  486 
Ludwigia,  658 
Lumbricaria,  139 
Lunihricites,  139 
Lunatia,  543 
Lunulicardium,  444 
Lunulites,  350 
Lutetia,  489 
Lutraria,  498 
Luzouia,  470 
Lychnocanium,  44 
Lycodes,  453 
Lycophoria,  394 
Lycophrys,  36 
Lymnaea,  574 
Lynceites,  735 
Lyonsia,  468 
Lyonsieila,  4G8 
Lyia,  406,  560 


Lyriocrinus,  189 
Lyriopecten,  457 
Lyrodesnia,  455 
Ijyropora,  341 
Lysactinella,  60 
Lysiosquilla,  768 
Lysis,  558 
Lysocystites,  157 
Lytoceras,  652 
Lyttonia,  387 

Macamlrevia,  406 
Macarobrinus,  194 
Maccoya,  303 
Maeha,  495 
Machilis,  819 
Machomya,  466 
Mackenzia,  118 
Maclurea,  527 
Maclurina,  527 
Macoina,  494 
Macraster,  294 
Macrocallista,  493 
Macrocaris,  751 
Macrocephalites,  663 
Macrocheilus,  536 
MacrocMlina,  536 
Macrocrinus,  195 
Macrocypris,  740 
Macrocystella,  157 
Macrodon,  441 
Macronotella,  738 
Macropneustes,  297 
Macroscaphites,  653 
Macroschisma,  526 
Maciostylocrinus,  191 
Mactra,  497 
Mactrella,  497 
Mactroderma,  497 
Mactromya,  466 
Mactropsis,  498 
Mactrotoma,  497 
Madrepora,  107 
Maeneceras,  630 
Magalompliala,  522 
Magas,  407 
Magasella,  407 
Magellania,  408 
Magila,  763 
Magnesia,  277 
Mala,  766 
Maiocercus,  791 
Malacostronia,  124 
Malaptera,  551 
Malletia,  441 
Malleus,  449 
Malocystis,  151 
Mammites,  669 
Mandaloceras,  612 
Mangilia,  564 
Mannia,  408 
Manticoceras,  631 
Maragnicrinus,  222 
Maretia,  297 

Margarites,  532,  638,  640 
Margarya,  544 
Marginaria,  349 
Marginella,  560 
Marginifera,  390 
Marginulina,  30 
Mariacrinus,  190 
Marmolatella,  533 
Marsipella,  24 
Marsipocrinus,  199 
Marsupiocr-inus,  189,  199 
Marsupites,  235 
Martesia,  501 
Marti  nia,  412 
Martiniopsis,  412 
Mastigocrinus,  220 
Matercula,  444 
Matheria,  442 
Matheronia,  477 
Mathilda,  537 
Matthewia,  571 
Matuta,  765 


832 

Mazza,  560 
MiizziUirui,  560 
Mecochirus,  763 
Mecynoflon,  471 
M«-(llicottia,  633 
Mcdusaster,  251 
Meekechiims,  307 
Meekella,  387 
Meekoceras,  645 
Meekocytis,  154 
Meekopora,  330 
Medusites,  134      ^ 
Megacystites,  150 
Megalanteris,  402 
Megalaspis,  718 
Megalithista,  57 
Megjilodon,  453 
Megalograptus,  783 
Megalomastoma,  540 
Megalomus,  454 
Meganeura,  809 
Meyanteris,  402 
Megaphyllites,  641 
Megapodagrion,  811 
Megaptera,  445 
Megaraphidia,  812 
Megarhiza,  59 
Megarhynchus,  392 
Megatebennus,  526 
Megateuthis,  682 
Megathyris,  405 
Megerlea,  405 
Megerlina,  408 
Megistocrinus,  195 
Meiocardia,  491 
Melanipus,  574 
Melanagrion,  811 
Melania,  547 
Melanopsis,  548 
Meleagrina,  448 
Melia,  600 
Meliceritites,  324 
Meilita,  288 
Melo,  561 
Meloceras,  611 
Melocrinus,  190 
Melonechinus,  304 
Melonella,  56 
Melongena,  557 
Melanites,  304 
Melonoceras,  611 
Membranipora,  349,  350 
Membraniporella,  350 
Meneghiniceras,  652 
Menipea,  348 
Meniscopora,  353 
Menophyllum,  84 
Mentzelia,  412 
Meoma,  297 
Meretrix,  493 
Merista,  516 
Meristella,  415' 
Meristina,  415 
Meristocrinus,  204 
Meristospira,  415 
Meiocrinus,  215 
Mero'e,  492 
Mesalia,  546 
Mesenterijmra,  319 
Mesidotea,  758 
Mesite.%  156 
Mesoblastus,  172 
Mesoceras,  597 
Mesocrinus,  229 
Mesocystis,  156 
Mesodesma,  498 
Mesograptus,  130 
Mesoleuctra,  808 
Mesonacis,  714 
Mesoneniura,  808 
Mesothyra,  753 
Mesotreüi,  377 
«Mesotryf);i,  333 
Mospilocrinus,  203,  232 
Mesuropetala,  810 
Metablastus,  170 


TEXT-BOOK  OF  PALEON  TOLOGY 


Metacoceras,  605 
Metacrinus,  234 
Metalia,  297 
Metaplasia,  412 
Metaporliinus,  202 
Metasibirites,  639 
Metatirolites,  648 
Metengonoceras,  671 
Metichthyocrinus,  205 
Metoiceras,  671 
Metopaster,  250 
Metoptoma,  520 
Metriophylliun,  84 
Metiila,  557 
Michelinia,  115 
Mickwitzella,  371 
Mickwitzia,  370 
Micrabacia,  103 
Micraster,  296 
Microblastidium,  67 
Microceras,  521 
Microconchus,  138 
Microcrinus,  237 
Microcylus,  82 
Microcyphus,  282 
Microderoceras,  656 
Microdiscus,  711 
Microdoma,  531 
Microdon,  471 
MicrOinaia,  766 
Micromelania,  545 
Micromitra,  370 
Micropedina,  278' 
Micropocrinus,  241 
Micropora,  351 
Microporella,  351 
Micropsis,  280 
Microschiza,  537 
Microseris,  102 
Microsolena,  104 
Microthorax,  766 
Microthyris,  406 
Microtropites,  638 
Mila,  444 
Miliola,  38 
Miliolina,  38 
Millepora,  119 
Millericrinus,  231 
Milneria,  476 
Miltha,  486 
Miltites,  639 
Miiuoceras,  629 
Mimocystites,  157 
Mimulus,  387 
Miocidaris,  272 
Mischoptera,  813 
Miskoia,  136 
Missouricrinus,  215 
Mithracites,  765 
Mitoclema,  321 
Mitra,  560 
Mitraefusus,  557 
Mitraster,  250 
Mitrocystella,  150 
Mitrocystites,  150 
Mixosiphonoceras,  610 
Mixotermes,  797 
Mizalia,  790 
Mohergia,  375 
Modelia,  529 
Modiella,  449 
Modiola,  463 
Modiolaria,  463 
Modiolodon,  462 
Modioloides,  439 
Modiolopsis,  462 
Modiomorpha,  462 
Mogulia,  523 
Mohrensternia,  545 
Moira,  296 
Mojsvarites,  651 
Molaria,  776 
Moltkia,  110 
Monachocrinus,  230 
Monia,  461 
Monmorella,  373 


Monobolina,  377 

Monoceros,  558 

Monocondylaea,  455 

Monodacna,  490 

Monodonta,  531 

Mouograptus,  132 

Monoi^hyllites,  650,  651 

Monopleura,  478 

Monoprion,  132 

Monopteria,  448 

Monorakos,  727 

Monotls,  448 

Monotrypa,  339 

Monotrypella,  336 

Monticulipora,  381 

Montlivaltia,  96 

Moorea,  738 

Moorefieldella,  398 

Mopalia,  513 

Morio,  554 

Mormolucoides,  811 

Morphoceras,  664 

Mo7-risia,  405 

Morfeoii  iceras,  672 
Mourlonia,  524 
Mucronella,  352 
Muehlfeldtia,  405 
Muelleria,  455 
Muensterites,  648 
Muensteroceras,  636 
Mulinia,  498 
Mulletia,  447 
Multicavea,  326 
Multitubigera,  322 
Multizonopora,  326 
Muniericeras,  669 
Murchisonia,  525 
Murex,  558 
Musculus,  403 
Mutela,  455 
Mutiella,  487 
Mya,  499 
Myacites,  464 
Myalina,  449 
Myalinodonta,  448 
Myalinoptera,  449 
Mycetopoda,  455 
Mycocrinus,  214 
Myelodactylus,  212 
Myocaris,  754 
Myochama,  467 
Myoconcha,  402 
Myodora,  467 
Myonera,  470 
Myonia,  566 
Myophoria,  456 
Myophoriopsis,  457 
Myoplusia,  440 
Myopsis,  466 
Myrianites,  141 
Myriopora,  353 
Myriozoum,  353 
Myristica,  557 
Myrtea,  486 
MyrtillocrinuH,  210 
Mysidia,  449 
Mystrophora,  393 
Mytilarca,  445 
Mytilops,  449 
Mytilopsis,  463 
Mytilus,  463 

Nacella,  520 
Naiadites,  451 
Naites,  141 
Nannites,  637 
Nanno,  596 
Nannogouiphus,  810 
Nanocrinus,  219 
Nanthacia,  799 
Naranaio,  494 
Naraoia,  733 
Narthecoceras,  596 
Nassa,  556 
Natica,  542 
Naticella,  533 


Naticopsis,  533 
Natiria,  533 
Naumacliocrinus,  230 
Nautilus,  607 
Neaera,  469 
Neatretia,  400 
Nebalia,  749 
Necrocarcinus,  765 
Necrogammarus,  759 
Necroscilla,  768 
Necrotaulius,  814 
Nectotelson,  756 
Neithea,  Abi 
Nemagraptus,  130 
Nemapodia,  141 
Nemastomoides,  791 
Nemataxis,  344 
Nematocrinus,  214 
Neinatopöra,  343 
Nematotrypa,  344 
Nematura,  545 
Nemertites,  141 
Nemodon,  442 
Neobolus,  372 
Neocatillus,  447 
Neocatopygus,  290 
Neocomites,  668 
Neocrinus,  233 
Neocystites,  160 
Neohindia,  56 
Neolampas,  291 
Neolenus,  716 
Neoliuiulus,  776 
Neomegalodon,  454 
Neorthophlebia,  813 
Neoschizodus,  456 
Neothyris,  408 
Nephriticeras,  604 
Nephrops,  764 
Neptocarcinus,  767 
Neptnnea,  557 
Neptunus,  767 
Nereites,  141 
Nerinea,  549 
Neriuella,  549 
Nerita,  534 
Neritaria,  534 
Neritina,  534 
Neritodomus,  534 
Neritoma,  534 
Neritomopsis,  533 
Neritopsis,  534 
Neumayria,  603 
Neusina,  26 
Neverita,  543 
Nevvberria,  401 
Nicliolsonella,  334 
Nicholsonia,  112,  345 
Nicomedites,  645 
Nieszkowskia,  725 
Nileus,  719 
Ninella,  529 
Nipterclla,  57 
Nipterocrinus,  204 
Nisusia,  380 
Nodelea,  324 
Nadicrescis,  326 
Nodosaria,  30 
Noetia,  443 
Noetlingia,  394 
Nomismoceras,  631 
Norella,  399 
Norites,  633 
Normann  ites,  663 
Nothoceras,  613 
Nothozoe,  751 
Notothyris,  403 
Novaculina,  495 
Nubecularia,  37 
Nucleatula,  401 
Nucleocrinus,  171 
Nucleolites,  289 
Nucleospira,  415 
Nucula,  440 
Nuculana,  440 
Nuculina,  441 


INDEX 


833 


NiirahinUna,  36 
NummuUtes,  35 
Nuttaliua,  513 
Nyassa,  452 
Nyctilochus,  555 
Nyctopora,  114 
Nymphaeoblastus,  172 
Nymphaeops,  703 
Nyniphalites,  815 
Xympliaster,  250 
Xystia,  545 

OliliqodDi,  452 
Obolella,  875 
Oholellhm,  373 
Obolus,  371 
Ochetoceras,  G5S 
Ücinehrn,  55S 
Octoiiaria,  730 
Octotremacis,  111 
Oeulina,  95 
Oculospongia,  71 
Odaraia,  750 
Odontocems,  6(59 
Odontoperna,  447 
Odontopleura,  722 
OdontotTjipa,  330 
Odostomia,  537 
Oecoptycliiiis,  665 
Oecotraustes,  658 
Oedisclila,  798 
OchlerteUa,  377 
Oesia,  141 
Offa,  742 
Offaster,  203 
Oiiygid,  718,  719 
Ogygiocaiis,  718 
Ogygites,  710 
Ogygopsis,  718 
Ohiociinus,  212 
Olcostephanus,  664 
Oldhaniia,  388 
Olenelloides,  714 
Olenellus,  714 
Olenikites,  647 
Olenoides,  716 
01«ims,  715 
OUcjiicrinus,  206 
Oligoponis,  304 
Oligotoina,  563 
Oliva,  562 
Oliv(Hiite'<,  171 
Olivella,  562 
Ollucriiius,  188 
Onuilaxis,  538 
Ombonia,  38(; 
Ompholia,  546 
Omphalocirrns,  527 
Omplialophyllia,  10:? 
Omphalopteru.s,  543 
Oniplialotroclnis,  528 
Ompliyiiia,  85 
ünchoiiietüpus,  710 
Oncliotrocluis,  04 
Oncoceras,  611 
Oucocliilus,  534 
Oncocnnus,  203 
Oncodoceras,  606 
Oiicomo,  552 
Oucopaiia,  7t'i3 
Oncophora,  404 
Oncospira,  531 
Onithochitou,  513 
Onycliastor,  255 
Onychia,  444 
Onychocella,  350 
Onychocrinus,  20*! 
Onychopterus,  782 
Ooceras,  610 
Oonia,  537 
Oonoceras,  610 
Opabinia,  732 
Opevculina,  35 
Ophiceras,  (J45 
Ophidioceras,  (iOl 
Ophileta,  527 

VOL.   I 


Opliioceras,  655 
Ophiücoma,  256 
Ophiocrinus,  180 
Ophiocnnus,  212,  221 
I  Ophiocten,  256 

Ophioderma,  256 
j  Ophiolepis,  256 

Ophiomusium,  256 
I  Ophlrapliidites,  51 
Ophiurella,  256 
Ophiurites,  237 
I  Ophlura,  256 
I  Opthalmidiimi,  38 

Opiliotarbus,  791 
I  Opis,  473 
j  Opisoiiia,  473 
i  Opisthoptera,  445 
I  Oplophorus,  761 

Oppelia,  658 
I  Oppelismilia,  07 

Orbiceila,  08 
!  OrhiceUa,  377 
j  Orbiculina,  30 
I  Orbicnloidea,  377 
j  Orbignyella,  331 
I  Orbignyia,  482 
\  Orbipecten,  457 
'  Orbipora,  336 
I  Orbitoides,  36 
Orbitolina,  27 
Orbitolites,  30 
Orbitremites,  171 
Orbulina,  31 
Oreaster,  251 
OHoi^foma,  528 
Oriskania,  401 
Ormoceras,  609 
Ornithaster,  296 
Ornithella,  406 
Orocystites,  152 
Oropliocrinus,  169 
Orozoe,  752 
OrtJuiinhonites,  381 
Orthaulax,  553 
Ortliidium,  385 
Orthis,  381 
Orthiffina,  392 
Ortlioceras,  598 
Orthocidaris,  274 
Orthocriuus,  187 
Orthodesnia,  462 
Orthodontiscus,  470 
Orthograptus,  130 
Orthoidea,  407 
Orthonoimiea,  408 
Orthonota,  462 
Ortlionychia,  541 
Orthophlebia,  813 
Orthopora,  344 
Orthopsis,  276 
Orthoptf/chus,  479 
Orthorhynchula,  396 
Orthostoma,  566 
Orthostropliia,  382 
Orthotetes,  386 
Orthotheca,  571 
Oiihothete.%  386 
Orthothetina,  387 
Orthothrix,  391 
Orthotichia,  383 
Orthotoiua,  406 
Orthotropia,  305 
Ortonia,  139 
Orusia,  381 
Oryctocephahis, 
Osculipora,  322 
Osiliiius,  531 
Osniyliis,  813 
Ostracotenthis,  683 
Ostrea,  450 
Otoceras,  646 
OtopoTiia,  540 
Otostoma,  534 
Ottawacrimis,  215 
Ottoia,  141 
Otusia,  380 


•16 


Ovula,  554 
Ovulactaeon,  566 
Owenella,  521 
Owenites,  637 
Oxyclymenia,  628 
Oxydiscus,  522 
Oxygyrus,  536 
Oxynoticeras,  660 
Oxystele,  531 
j  Oxytoina,  448 
Oxyuropoda,  757 

Pachastrella,  51 
Pachinion,  59 
'  Pachycardia,  452 
Pachyclypeus,  285 
Pachydictya,  346 
i  Pachydiscus,  667 
I  Pachydomella,  740 
1  Fachydon,  499 
i  Pachygyra,  101 
;  Pachylasnia,  747 
Pachylocrinus,  222 
Pachymagas,  407 
I  Pachymegalodon,  454 
'  Pachymytilus,  463 
i  Pachyphyllum,  86 
!  Pachypouia,  528 
Pacliypora,  114 
Pachypteria,  459 
1  Pachyrhynchus,  407 
I  Pachyrisma,  454 
Pachystroma,  123 
'  Pachyteichisma,  65 
j  Pachyteuthis,  682 

Pachytylodia,  71 
I  Paedeumias,  714 
Pagurus,  764 
Palaeacis,  106 
Palaeacmaea,  520 
Palaeamutela,  452 
Palaeanodonta,  452 
Palaeastacus,  764 
Palaeaster,  248 
Palaeechinus,  303 
Palaega,  758 
Palaeinachus,  765 
Palaemysis,  757 
I  Palaeoblattina,  820 
'  Palaeobolus,  371 
Palaeobrissus,  297 
Palaeocaiupa,  793 
;  Palaeocardita,  475 
Palaeocaris,  755 
Palaeocarpilius,  767 
,  Palaeochrysa,  813 

Palaeoclymenia,  600 
!  Palaeocöma,  251 
!  Palaeocorbis,  487 
Palaeocorystes,  765 
Palaeocrania,  379 
Palaeocreiisia,  747 
I  Palaeocrinus,  217 
Palaeocyclus,  82 
Palaeocypris,  740 
Palaeocystites,  152 
Palaeodiscus,  290 
j  Palaeogainmarus,  759 
Palaeogoiiiatites,  630 
i  Palaeograpsus,  766 
'  Palaeolampas,  291 
!  Palaeonianon,  56 
I  Palaeomya,  484 
'  Palaeouarica,  533 
'  Palaeonautüus,  600 
'  Palaeonectria,  249 
I  Palaeoneilo,  440 
Palaeonisa,  537 
Palaeophiura,  254 
Palaf'ophoiius,  787 
Palaeopinna,  446 
Palaeopneustes,  295 
Palaeoporites,  112 
Palaeopsylla,  817 
I  Palaeorchestia,  756 
:  Palaeosaccus,  61 


Palaeosceptron,  110 
Palaeosolen,  496 
Palaeostella,  249 
Palaeostonia,  297 
Palaeothrip.s,  800 
Palaeotropus,  297 
Palasterina,  251 
Palasteriscus,  251 
Paleanatina,  438 
Palearca,  442 
Palenarthrus,  793 
Paleocardia,  445 
Paliiigenia,  809 
Palinurina,  763 
Pallium,  457 
Palmocystis,  155 
Paltodus,  140 
Paltopleuroceras,  659 
Paltorhynchus,  805 
Pahidiim,  544 
Panda,  576 
Pandora,  467 
Panomya,  500 
Panope,  500 
Panopea,  500 
Panopeus,  767 
Papliia,  493,  498 
Papyridea,  490 
Paracardium,  439 
Paraceltites,  640 
Paracochloceras,  650 
Paractinoceras,  609 
Paracyathus,  95 
Paracyclas,  485 
Paradoxechiniis,  282 
Paradoxides.  714 
Paragyninites,  645 
Parajurvavites,  629 
Parakymatites,  644 
Parala'nipas,  290 
Paralecanites,  644 
Paralegoceras,  636 
Parallelodon,  441 
Parambonites,  393 
Paramelania,  548 
Paramya,  499 
Parannites,  637 
Paranomia,  461 
Parapachydiscus,  667 
Paraparchites,  737 
Paraphorhvnchus,  39S 
Paraphyllites,  630 
Parapopanoceras,  641 
Parapronorites,  633 
Pararca,  439 
Pararcestes,  642 
Parastarte,  494 
Parastropliia,  394 
Parathisbites,  648 
Paratropites,  638 
Parazyga,  414 
Parichthyocrinus,  206 
Parisoerinus,  218 
Parkeria,  120 
Parkinsonia,  665 
Parmophorus,  526 
Parodoceras,  631 
Paroniceras,  657 
Paropsis,  448 
Parotermes,  804 
Paryphostoma,  537 
Pasceolus,  72,  160 
Passyia,  488 
Patella,  520 
Patellina,  33 
Patelliocrinus,  191 
Patellostiuni,  522 
Pateiiaria,  322 
Pateriiia,  370 
Paterula,  372 
Patrocardiiun,  444 
Pattersonia,  62 
Paronaria,  110 
ParotuMijera,  322 
Paxillosi,  682 
i  Peachella,  714 

3  H 


TEXT-BOOK  OF  PALEONTOLOGY 


Peccliiolia,  469 
Pecten,  457 
Pediilum,  447 
Pedicularia,  554 
Pedina,  278 
Pedinopsis,  277 
Peduiii,  458 
/Vt,N;/iot'cm,s,  üOl 
J'fUuiia,  323 
Polagodiscus,  378 
Pelagothuria,  313 
Pelanechinus,  278 
Peltairon,  533 
Peltastes,  279 
Peltocaris,  754 
Peltoceras,  (565 
Peltura,  715 
Peniphix,  762 
Peiieroplis,  39 
Pennutulites,  110 
Pemiii-ftepora,  343 
Pentaceros,  251 
Pentacrinus,  232,  233 
Pentactinella,  418 
Pentadid,  224 
Pentagoiiaster,  249 
Peiitagonia,  416 
Pentainerella,  395 
Pe.ritame.rocenis,  612 
Pentamenis,  395 
Pentaphylluin,  84 
Pentastere,  8!>5 
Peiitata,  439 
Pentephyllum,  172 
Pentremites,  169 
Pentremltidea,  169 
Pephricaris,  752 
Peregrinella,  399 
Peieiraea,  552 
Perganiidea,  449 
Pergensella,  320 

Pericosimis,  296 

Pericyclus,  636 

Periechocrinus,  194 

Periglyptocrimis,  190 

P«Timecturu.s,  768 
Perijietoceras,  606 

Peripleurites,  649 

Periploina,  467 

Periplomya,  466 

Peripneiistes,  297 

Peripora,  321 

Perischocidaris,  306 

Perischodomus,  306 

Perispliinctes,  663 

Peri  Stern  ia,  560 

Perla,  808 

Periia,  447 

Pernoiieeten,  457 

Peniostrea,  447 

Pernnella,  69 

Peroniceras,  672 

Peronidella,  69 

Peronoceras,  6(>2 

Peroiiopora,  332 

Peronopsis,  710 

Pwplicaria,  560 

Persona,  bbb 

Petalfixis,  86 

Petaloconchus,  547 

Petalocrinus,  217 

Petalograptus,  130 

Petalopora,  324 

Petalospyris,  44 

Petalotrypa,  337 

Petersia,  553 

Petigopora,  333 

Petigiinis,  718 

Potraia,  72 

Petrosfer,  248 

Petricola,  494 

Petricolaria,  494 

Petrocraiiia,  378 

Pexidella,  418 

Phacites,  35 

l'hacoceras,  604 


Phacoides,  486 
Phacopidella,  726 
Phacops,  726 
Pliaenopora,  345 
Pliaenoschisiiia,  168 
Plialacroma,  710 
Phalangella,  320 
Phalaugiotarbus,  791 
Phanerotinus,  527 
Pharella,  496 
Pharetra,  374 
Pharetrella,  571 
Pliaretriuin,  508 
Pharostoma,  724 
Phasganocaris,  751 
Phasianella,  529 
Phasiamis,  529 
Phenacoceras,  632 
Phenacolepas,  526 
Phenacolestes,  811 
Phialocrinux,  225 
Phidolophora,  353 
Philhedra,  378 
Philine,  568 
Philippiella,  459 
Piiilis,  487 
Phillippites,  647 
Phillipsastrea,  87 
Phillipsia,  721 
Phillipsocrinus,  197 
Philobrya,  449 
Philocrinus,  223 
Phimocrinus,  209 
Phloioceras,  604 
Phoenicocrinus,  194 
Pholadella,  465 
Pholadocaris,  754 
Pholadoinya,  466 
Pholas,  501 
Pholidechinus,  302 
Pholidocidaris,  300 
Pholidophylluni,  84 
Pholidops,  379 
Pliolidostropia,  385 
Plionnedites,  648 
Phormopora,  324 
Phormosella,  60 
Phorniosoma,  278 
Phorus,  543 
Plios,  556 
Phractopora,  346 
Phragmatoecites,  815 
Pliragnioceras,  613 
Phragmodictya,  61 
Phragmolites,  522 
Phragmosfoma,  523 
Phragmoteutliis,  684 
Phragniotlieca,  571 
Phreatura,  739 
Phrynocrinus,  230 
Phryniis,  788 
Phryssonotus,  793 
Phthonia,  438 
Phycticeras,  658 
Phyllacanthus,  273 
Phyllangia,  98 
Phyllobrissus,  290 
Phylloceras,  652 
Phyllocoenia,  101 
Phyllocrinus,  240 
Phyllodictya,  346 
Pliyllodocites,  141 
Phyllofrancia,  322 
Phyllograptus,  129 
Pliyllonotus,  558 
Phyllopoi-a,  341 
l'hyUa)K)ri7ia,  340 
Phyllosmilia,  100 
Phylloteuthis,  688 
Phyloblatta,  803 
Phyniatella,  54 
l'hymatifer,  527 
Pliyniechiiins,  277 
Pliysa,  574 
Pliysetocrinus,  197 
Pliysocaris,  751 


Pliysodoceras,  666 
Physospoiigia,  Gl 
Phlltocrinuis,  2H7 
Phytogyra,  102 
Pictetocrlnus,  233 
Pictonia,  664 
Pikaia,  137,  141 
Pileolus,  535 
Pileopsis,  541 
Püeotrypa,  329 
Pileus,  285 
Piloceras,  596 
Pilocystites,  150 
Pimentes,  662 
Pinacites,  630 
Pinacoceras,  636 
Pinacophyllum,  101 
Pinacotrypa,  330 
Pinna,  446 
Pinnatopora,  342 
Pinnigena,  446 
Pinnocaris,  754 
Pionocrinus,  194 
Pionodema,  382 
Pironaea,  482 
Pisanella,  556,  560 
Pisania,  556 
Pisidiuiii,  475 
Pisocrinus,  208 
Pithodea,  537 
Placenta,  461 
Placenticeras,  671 
Placiphorella,  513 
Placites,  636 
Placocoenia,  101 
Placocystites,  151 
Placoparia,  725 
Placophoro])sis,  513 
Placophyllia,  100 
Placopsilina,  26 
Placosmilia,  100 
Placima,  461 
Placunanoinia,  461 
Plaeunema,  461 
Placunopsis,  461 
Plaesioniys,  382 
Plagioglypta,  509     . 
Plagioptychus,  479 
Plagiostoma,  460 
Planaxis,  540 
Planctoceras,  600 
Planetoceras,  604 
Planolites,  141 
Planorbella,  570 
Planorbis,  574 
Planorbulina,  32 
Planulina,  33 
Plasmopora,  112 
Plasmoporella,  112 
Platidia,  405 
Platyacra,  531 
Platybrissus,  295 
Platyceras,  541 
Platychilina,  534 
Platychonia,  58 
Platyclymenia,  628 
Platycrinus,  199 
Platycystis,  150 
Platynietopus,  721 
Platymya,  466 
Platyodon,  499 
Platyostonia,  541) 
Platyperla,  808 
Platyschisnia,  527 
Platystrophia,  381 
Plaxiphora,  513 
Plecotrema,  574 
Plectaiiibonites,  384 
Plectella,  384 
Plectoceras,  601 
Plectoderma,  61 
Plectodermatium,  67 
Plectodon,  470 
Plectomya,  466 
Plectorthis,  381 
Pleiodon,  455 


I  Plesiastraea,  98 
j  Plesiocyprina,  472 
J'lesiüdicenis,  477 
Ple.siolampas,  291 
Plesiosira,  791 
Plesioteuthis,  688 
Plesiothyiis,  407 
Plethoniytiliis,  445 
;  Plethopora,  326 
j  Plethorhyncha,  397 
!  Plethospira,  525 
!  Pleurocaris,  756 
i  Pleurocera,  548 

Pleuroceras,  548,  659 
j  Pleurocora,  97 

Pleurucrinus,  199 
i  Pleurocteniuni,  710 
i  Pleurocystites,  154 
'  Pleuiodiadema,  277 
!  Pleurodictyum,  114 
Pleuiodonta,  439,  576 
Pleuiolytoceras,  652 
Pleuioineris,  476 
Pleuroniya,  464 
Pleuronautilus,  606 
Pleuronotus,  527 
Pleiirophorus,  471 
Pleurorhynchus,  446 
Pleurostonia,  64 
Pleurotoma,  563 
Pleurotomaria,  524 
Plicatocrinus,  238 
Plicatula,  459 
PI  killen  t,  418 
J'lii'omyd,  466 
Plintliosella,  55 
Pliomera,  725 
Pliomerops,  725 
Pliorhytis,  495 
Plocophyllia,  101 
Plocoscvphia,  67 
Pluniatella,  354 
PlumafeUites,  354 
PJumuIifes,  744 
Plychophyllum,  85 
Plychospira,  414 
Poeillopora,  9ö 
Poculina,  570 
Podagrion,  811 
Podocidaris,  281 
PodoCTates,  763 
Podocyrtis,  44 
Poecilasma,  745 
Poecilomorphus,  658 
Poliniees,  543 
Pollia,  Ö56 
Pollicipes,  745 
Pollingeria,  187,  142 
Polorthus,  501 
Polyblastidiuni,  66 
PoJycerus,  232 
Polyclieles,  761 
Polycidaris,  274 
Polycoelid,  69,  82 
Polycyclus,  649 
Polycyphus,  278 
Polydonta,  531 
Polygnathus,  140 
Polygono.sphaerite.s,  72 
Polygyra,  576 
PoIy.ierea,  55 
PulyUpas,  745 
Polymarai)hinina,  54 
Polymorphina,  31 
Polymorphites,  657 
I  Polyochera,  789 
I  Polyodontd,  574 
j  Polyosepia,  64 
!  J'olypeltes,  190 
I  Polypliemoiisis,  537 
j  Polyphyllia,  102 
j  Polyphynia,  735 
j  Polyi)lectu.s,  660 
I  Polypoi-a,  341 

Polyptchite.s,  664 
I  Polyschide.s,  510 


ä 


INDEX 


835 


Polysolenia,  111 
Polystomella,  34 
Polytaxia,  325 
Polytoechia,  393 
Polytrerna,  326 
Polytremacis,  111 
Polytremaria,  525 
Polytropis,  528 
Polyxenus,  792 
Pomatias,  540 
Pomatocrinus,  231 
Pamatograptus,  132 
Pomatospirella,  418 
Pomocystis,  155 
Pontocypris,  740 
Popanoceras,  641 
Porcellia,  524 
Porella,  352 
Poricella,  353 
Porina,  352 
Poristoma,  353 
Porites,  107 
Porocidaris,  273 
Porocrinus,  160,  217,  225 
Poromya,  469 
Porosphaera,  121 
Porospongia,  65 
Portlockia,  539 
Portunites,  767 
Posidoniella,  449 
Posidonomypa,  449 
Potamides,  550 
Potamobius,  764 
Potainomya,  499 
Potamon,  767 
Poterioceras,  611 
Poteriocrinus,  222 
Potoceras,  606 
Pourtalesia,  298 
Praeanaspüles,  755 
Praearcturus,  758 
Praecardium,  439 
Praeglyphloceras,  636 
Praelima,  439 
Praelucina,  439 
Praesphaeroceras,  662 
Prasina,  464 
Prasopora,  332 
Preatya,  763 

Preconia,  472 

Prenaster,  296 

Prestwichia,  774 

Priamus,  561 

Primitia,  738 

Primitiella,  737 

Priinnoa,  110 

Prionastrea,  98 

Prioniodus,  140 

Prionomyrmex,  806 

Prionotropis,  672 

Priscochiton,  512 

Prismodictya,  60 

Prismopora,  346 

Pristiograptiis,  132 

Proarcetes,  642 

Proavites,  644 

Probeloceras,  631 

Probolaenm,  512 

Probolium,  726 

Proboscidella,  391 

Proboscina,  319 

Procardia,  466 

Procarnites,  635 

Procercopis,  819 

Procerites,  663 

ProcliiKicrinus,  213 

Prodromites,  634 

Prodryas,  815 

Producta,  390 

Productella,  389 

Productus,  390 

Proetus,  721 

Proflscheria,  474 

PrographuJarifi,  110 

Prohemerobius,  813 

Proidotea,  758 

VOL.   I 


Proisocrinus,  232 
Projovellania,  610 
Proleanites,  632 
Prolibyhea,  815 
Prolimulus,  774 
Prolobella,  462 
Prolobites,  629 
Prolucina,  486 
Prolystra,  815 
Promacnis,  438 
Promathilda,  537 
Promedlicottia,  633 
Promelocrinus,  190 
Pronannites,  636 
Pronites,  392 
Pronoe,  492 
Pronoella,  492 
Pronorites,  633 
Propeamusium,  458 
Propinacoceras,  633 
Proplanulites,  664 
Proptychites,  645 
Propygope,  404 
Proricaris,  754 
Prorokia,  472 
Proscorpius,  788 
Prosocoelus,  472 
Prosodacna,  490 
Prosopon,  765 
Prosostheiiia,  545 
Prospondylus,  469 
Prosserella,  412 
Protalochiton,  512 
Protaraea,  112 
Protaster,  254 
Protasteracanthion,  249 
Protaxocrinus,  205 
Proteocystites,  156 
Proteroblastus,  156 
Proterocidaris,  306 
Protetraclis,  53 

Prot/cusites,  640 
Protholoturia,  313 
Prothyris,  438 
Protichnites,  142 
Proto,  546 
Protobactrites,  599 
Protobalaims,  746 
Protocardia,  490 

Protocaris,  732 
Protocidaris,  306 

Protocimex,  820 

Protocrinites,  156 

Protocrisina,  320 

Protocycloceras,  599 

Protocystis,  151 

Protodiceras,  454 

Protolimulus,  774 

Protolindenia,  810 

Protolycosa,  790 

Protoma,  546 

Protomya,  439 

Protonerita,  534 

Protonia,  390 

Protopalaeaster,  248 

Protopharetra,  105 

Protophasma,  801 

Protophragmoceras,  612 

Protopilio,  791 

Protoretepora,  341 

Protorhynclia,  396 

Protorthis,  380 

Protoschizodus,  472 

Protoscolex,  137 

Protosiphon,  376 

Protosolpuga,  789 

Protospongia,  60 

Protosycon,  71 

Protowarthia,  521 

Protozyga,  408 

Protrachyceras,  648 

Proutella,  347 

Pruiiocystis,  155 

Psammhelia,  95 

Psamniobia,  495 

Psammocarcinus,  767 


Psammosolen,  495 
Psecadia,  815 
Pselioceras,  606 
Psephidia,  494 
Pseiulalaria,  549 
Pseudamusium,  458 
Pseudedmondia,  484 
Psetbderiphyla,  474 
Pseudoastacus,  763 
Pseudobelus,  682 
Pseudocerithium,  549 
Pseudochaetets,  118 
Pseudocidaris,  275 
Pseudocrania,  379 
Pseudocrintes,  153 
Pseudocythere,  739 
Pseudodiadema,  277 
Pseudodiceras,  477 
Pseudofossarus,  533 
Pseudogalathea,  757 
Pseudoglossothyris,  404 
Pseudoglyphaea,  762 
Pseudohornera,  340 
Pseudokingena,  406 
Pseudolingula,  374 
Pseudoliva,  556< 
Psexxdomelania,  537 
Pseudometoptoma,  378 
Pseudomonotis,  448 
Pseudonautilus,  603 
Pseudonerinea,  549 
Pseudoniscus,  777 
Pseudopedina,  278 
Pseudoplacuna,  461 
Pseudoplocoscyphia,  54 
Pseudosageceras,  634 
Pseudoscalites,  539 
Pseudosirex,  806 
Pseudosphaerexochus,  725 
Pseudosquilla,  768 
Pseudostichopus,  313 
Pseudotoma,  563 
Pseudotropites,  660 

Pseudozampe,  820 

Psiloceras,  655 

Psilodon,  490 

Psilomya,  469 

Ptenoceras,  605 

Pteria,  447 

Pt^riiicopecten,  457 

Pterinea,  444 

Pterocaris,  754 

Pterocera,  552 

Pterocerella,  551 

Pterochiton,  512 

Pterocodon,  44 

Pterocoma,  237 

Pterocrinus,  230 

Pterodonta,  552 

Pteronautilus,  606 

Pteronites,  448 

Pteronotus,  558 

Pteroperna,  448 

Pterophloios,  389 

Pteropora,  346 

Pteropsis,  498 

Pterotheca,  571 

Pterotocrinus,  201 

Pterygometopus,  727 

Pterygotus,  784 

Ptilocella,  346 

Ptilocrinus,  238 

Ptilodictya,  344 

Ptilograptus,  128 

Ptilopora,  342 

Ptiloporella,  342 

Ptiloporina,  342 

Ptilotrypa,  345 

Ptychagnostus,  710 

Ptycharcestes,  642 

Ptychites,  637 

Ptychocaris,  752 

Ptychoceras,  653 

Ptychocladia,  318 

Ptychocrinus,  187 

Ptychodesma,  449 


Ptychomphalus,  524 
Ptychomya,  474,  493 
Ptychonema,  339 
Ptychoparia,  715 
Ptychoijyge,  719 
Ptychostoma,  536 
Ptychostylus,  548 
Ptygmatis,  549 
Ptyssoceras,  605 
Puella,  439 
Pugiunculus,  571 
Pugnax,  398 
Pugnellus,  552 
Pugnoides,  398 
Pugnus,  567 
Pulchellia,  671 
Pullastra,  493 
Pulsellum,  510 
Pulvinulina,  33 
Puncturella,  526 
Pupa,  576 
Pupillaea,  526 
Purpura,  558,  558 
Purpurina,  539 
Purpuroidea,  539 
Pustularia,  537 
Pustulopora,  320 
Puzosia,  667 
Pycinaster,  250 
Pycnocrinus,  189 
Pycnodonta,  450 
Pycnolithus,  112 
Pycnomphalus,  532 
Pycnopegma,  56 
Pyciiophyllum,  84 
Pycnosaccus,  203 
Pygaster,  285 
Pygaulus,  289 
Pygites,  403 
Pygocardia,  472 
Pygocephalus,  756 
Pygope,  403 
Pygorhynchus,  290 
Pygurus,  291 
Pyramidella,  537 
Pyrazus,  550 
Pyrenella,  550 
Pyrgia,  116 
Pyrgidium,  545 
Pyrgoma,  747 
Pyrgula,  545 
Pyrgulifer,  547 
Pyrgulifera,  547 
Pyricavea,  326 
Pyrina,  289 
Pyritonema,  62 
Pyrocystites,  150 
Pyrogopolon,  508 
Pyrula,  555^  557 
Pythina,  488 
Pythiopsis,  574 
Pyxidocrinus,  194 
Pyxis,  390 

Quebecia,  375 
Quenstedtia,  116,  494 
Quenstedtoceras,  663 
Quinqueloculina,  38 
Quoyia,  540 

Radiocavea,  326 
Radiofascigera,  323 
Radiolites,  481,  482 
Radiopora,  326 
Radula,  460 
Rafinesquina,  384 
Ramulina,  31 
Ranella,  555 
Rangia,  498 
Raniella,  765 
Raiiina,  765 
Raninoides,  765 
Rapaiia,  558 
Raphidia,  812 
Raphiojjhorus,  712 
Raphistoma,  527 

3  H  2 


836 


TEXT-BOOK  OF  PALEONTOLOGY 


3LM 


Rajilii.st(>i 
Kai-liistoinina,  iVJ» 
liiiphitoma,  i>Oi 
Rastrites,  132 
Receptaculites,  72 
Jieckur,  769 
Recula,  797 
Redlichella,  376 
Redonia.  440 
Regina,  '431) 
ReifliiiKi1>'s.  t)4T 
Reiiieckia,  665 
Remeleoceras,  607 
Remondia,  474 
Remopleurides,  717 
Rensselaeria,  400 
liensselandia,  401 
Reo])]iax,  25 
Rci.taria,  :5-20 
R.'l.t.'l.'a,  824 
Reptuciivea,  324 
Reptocea,  323,  326 
Reptoceritites,  324 
Rpptofascigera,  320 
Rt'ptoiiuilticava,  326 
Rf])r()inultielausa,  325 
Reptomulti.sparsa,  320 
Requienia,  477 
Retecava,  320 
Jietelm,  325 
Retenoa,  322 
Reteocrinus,  186 
Retepora,  353 
Reteporina,  342 
Reticularia,  412 
Reticiilipora,  325 
Retiograptus,  131 
Retiolites,  132 
Retusa,  568 
Retzia,  414 
Rhabdammina,  24 
Rhabdoceras,  649 
Rhabdocidaris,  273 
Rhabdomeson,  343 
Hhabdophyllia,  99 
Rhabdopleura,  539 
Rliabdosispongia,  60 
Rhabdus,  509 
Rliacodiscula,  55 
Rhacophyllites,  652 
Rhadinoceras,  604 
Rhadinocrinus,  221 
Rhaetina,  403 
Rhagadinia,  55 
Rhagasostoma,  351 
Rhaphanocrinus,  187 
Rhaphidonema,  71 
Rhectocyma,  472 
Rhinacantha,  568 
Rhinecei-as,  604 
Rhinidictya,  345 
Rhinobolus,  373 
Rhinobrissus,  297 
Rhinocaris,  753 
Rhinoclama,  470 
Rhinopora,  347 
Rhipidocardium,  446 
Rhipidocrinus,  189 
Rhipidocystis,  150 
Rhijndogorgia,  110 
Rhipidogyra,  102 
Rhipidomella,  382 
Rliipiodomys,  382 
RhipidoiK>ra,  321 
Rhizammina,  24 
Rliizangia,  97 
Rhizocriims,  229 
Rhizophyllum,  88 
Rhizoporidium,  121 
Rliizopoterion,  66 
Rhizostomites,  134 
Rhodaraea,  106 
Rliodocrimis,  188 
Rhodopliyllum,  86 
Rhoechinus,  806 
Rhombifera,  207 


Rhonibina,  741 
Rhombopora,  343 
Rhombopteria,  444 
Rhombotrypa,  337 
Rhopalocoma,  251 
Rliopalocriiius,  206 
Rhopalonaria,  317 
Rhynchidia,  533 
Rhvnchomya,  466 
RliVHclionella,  398 
Rhvnchonellina,  399 
Kliynchopora,  398 
lihynchojmrina,  398 
Rhynchora,  408 
Rhynchorina,  408 
Rhynchorthoceras,  601 
Rhynchospira,  414 
Rhynchostreon,  450 
Rhynchotetra,  398 
Rhynchotrema,  396 
Rhyncliotreta,  397 
Rhyiieopygus,  290 
Rhytimya,  465 
Ribeirella,  732 
Ribeiria,  732 
Riclithofenia,  391 
Ricinula,  558 
Rimella,  553 
Rimula,  526 
Ringicula,  567 
Ringinella,  567 
Rissoa,  546 
Rissoina,  545 
Rizoceras,  610 
Rocellaria,  500 
Roemeraster,  251 
Roemerella,  378 
Roemerispongia,  61 
Roemeroceras,  671 
Romingeria,  116 
Romingerina,  401 
Rostellaria,  552 
Rostellites,  561 
Rostranteris,  403 
Rotalia,  33 
Rotella,  532 
Rotellina,  532 
Rotlipletzia,  541 
Rotula,  288 
Rouaiiltia,  563 
Roudairia,  471 
Rowleyelli,  403 
Rima,  287 
Rupertia,  33 
Rustella,  370 
Rutoceras,  603 
Rutotia,  448 
Ryderia,  469 
Ryticeras,  603 

Saccammina,  25 
Saccohlastus,  170 
Saccocaris,  751 
Saccocoma,  239 
Saccocrinus,  194 
Saccorhiza,  25 
Saccospongia,  57 
Sactoceras,  608 
Sagda,  576 
Sageceras,  634 
Sagenites,  639 
Sagenina,  25 
Sagenocrinus,  204 
Sagitta,  135 
Saintia,  461 
Salenia,  279 
Salicornaria,  348 
Salmacis,  282 
Salpingostoma,  521 
Saiteraster,  249 
Salterella,  572 
Saniiisonocrinus,  197 
Sandbergeria,  550 
Sandlingites,  648 
Sanguinolaria,  495 
Sanguinolites,  438 


Sannionites,  595 
Sao,  715 
Sarmaticus,  529 
Saxicava,  499 
Saxidomus,  493 
Scaccliinella,  387 
Scaevola,  531 
Scalaria,  538 
Scalaripora,  346 
Sealdia,  484 
Scalites,  527 
Scalpellum,  745 
Scambula,  474 
Scapha,  561 
Scapliander,  568 
Scaplianidia,  533 
Scapharca,  443 
Scaphella,  561 
Scaplieus,  763 
Scaphiocoelia,  401 
ScapMocrinus,   222,  225 
Scaphites,  670 
Scaphula,  443 
Scarabus,  574 
Scenella,  520 
Scenellopora,  328 
Scenidium,  393 
Sceptropora,  343 
Scliellwienella,  386 
Schiosia,  479 
Schistoceras,  636 
Schistoi)hyllocera.s,  652 
Schizambou,  376 
Schizamhonia,  376 
Schizaster,  296 
Schizoblastus,  171 
Schizobolus,  377 
Schizochiton,  513 
Schizocrania,  377 
Schizocrinus,  189 
Schizocystis,  155 
Schizodentalium,  509 
Schizodesma,  498 
Schizodiscus,  524,  735 
Schizodus,  456 
Schizogonium,  525 
Schizolopha,  525 
Schizonema,  382 
Schizopholis,  375 
Sehizoplioria,  383 
Schizoplax,  513 
Schizoporella,  352 
Schizoramma,  382 
Schizorhabdus,  66 
Schizostoma,  353,  527 
Schizothaerus,  498 
Schizotreta,  378 
Schloenbachia,  672 
Schlotheimia,  657 
Schlueteria,  667 
Schmidtella,  737 
Schmidtia,  371 
Schroederoceras,  600 
Schuchertella,  386 
Schuchertina,  370 
Schultzicrinus,  219 
Schwagerina,  33 
Sclntilla,  488 
Scipionoceras,  654 
Sclerocrinus,  240 
Scolecoderma,  141 
Scoliocystis,  155 
Scoliostoma,  538 
Scolithus,  141 
Scolocystis,  157 
Scolopendra,  793 
Sconsia,  555 
Scrobicularia,  495 
Scrupocellaria,  348 
Sculda,  769 
Scurria,  520 
Scutella,  287 
Scutellina,  287,  526 
Scutus,  526 
Scyllaridia,  763 
Scyphocrinus,  160, 190,  215 


Scytalia,  59 
Scytalocrinus,  224 
Sebargasia,  71 
Sedgwickia,  439 
Seebachia,  473 
Seeleya,  525 
Selenaria,  350 
Selenella,  401 
Selenopeltis,  723 
Selenopora,  330 
Seliscothon,  59 
Selkirkia,  136 
Sellaclymenia,  628 
Semele,  495 
Semicava,  326 
Semicea,  323 
Seniiclausa,  320 
Semicoscinium,  341 
Semielea,  324 
Seniifascipora,  321 
Semimulticavea,  326 
Seminula,  395,  418 
Semiopora,  346 
Semiplicatula,  461 
Senectus,  529 
Sepia,  686 
Septameroceras,  612 
Septifer,  463 
Septopora,  342 
Seraphs,  552 
Seriatopora,  96 
Serietubigera,  321 
Serpula,  137 
Serpulites,  139 
Serripes,  490 
Sestromostella,  71 
Setosella,  351 
Shumardella,  398 
Shumardia,  711 
Shumardites,  642 
Sibirites,  640 
Sicanites,  633 
Sicyocrinus,  221 
Siderastrea,  103 
Sidneyia,  786 
Sieberella,  395 
Siemiradzkia,  666 
Sigaretus,  542 
Sigmacystis,  151 
Silbyllites,  638 
Silenia,  469 
Silesites,  667 
Silia,  562 
Siliqua,  496 
Siliquaria,  547 
Siluraster,  249 
Silurina,  439 
Simbirskites,  664 
Simoceras,  666 
Sinuites,  521 
Sinum,  542 
Siphodictyum,  324 
Siphonalia,  557 
Siphonaria,  573 
Siphonentalis,  510 
Siphonia,  54 
Siphonocoelia,  69 
Siphonocrinus,  187 
Siphonodentalium,  510 
Siphonotreta,  375 
Siphoniotyphlus,  321 
Sirenites,  648 
Sismondia,  287 
Sistrum,  558 
Slimonia,  783 
Smaragdinella,  568 
Smilotrochus,  94 
Smittia,  352 
Smittina,  352 
Smittipora,  351 
Smittistoma,  353 
Solanocrinus,  237 
Solariella,  532 
Solarium,  538 
Solecardia,  488 
Solemya,  438 


INDEX 


837 


Solen,  496 
Solenastrea,  98 
Soleniscus,  538 
Solenocaris,  751 
Solenocheilus,  606 
Solenopleura,  716 
Solenopsis,  438 
Solenospira,  525 
Solidula,  565 
Sollasella,  54 
Sollasia,  71 
Sonneratia,  668 
Sonuinia,  660 
Sowerbiceras,  652 
Sowerbya,  496 
Spanila,  444 
Spaniodera,  798 
Spaniodon,  488 
Sparsicavea,  324 
Sparäicytis,  326 
Spatagocystis,  298 
Spatangopsis,  134 
Spatangus,  297 
Spatha,  455 
Spathiocaris,  754 
Spatiopora,  329 
Speo,  565 
Sphaenia,  499 
Sphaera,  487 
Sphaeraetinia,  120 
Sphaerechinus,  282 
Sphaerella,  487 
Sphaerexochus,  725 
Sphaeriola,  487 
Sphaerium,  475 
Sphaerobolus,  371 
Sphaerocaprina,  479 
Sphaeroceras,  663 
Sphaerocoelia,  71 
Si^haerocoryphe,  725 
Sphaerocriuus,  196,  218 
Sphaerocystites,  154 
Sphaeroldina,  31 
Sphaeronites,  155 
Sphaeropsocus,  804 
Sphaerulites,  482 
Sphenaulax,  64 
Spheniopsis,  470 
Sphenodiscus,  671 
Sjihenomya,  439 
Sphenopoterium,  106 
Sphenotrochus,  94 
Sphingites,  642 
Sphyradoceras,  601 
Spiloblattina,  803 
Spinigera,  551 
Spiractinella,  62 
Spirialis,  570 
Spirifer,  410 
Spiriferella,  410 
Spiriferina,  413 
Spirigera,  417 
Spirigerella,  418 
Spirigerina,  409 
Spirillina,  32 
Spiroceras,  670 
Spiroclausa,  325 
Spirocolex,  141 
Sjnrocyathus,  105 
Spirodentalium,  508 
Spiroloculina,  38 
Spirophyton,  141 
Spiroplecta,  27 
Spiropora,  320 
Spirorbis,  138 
Spirostylus,  537 
Spirula,  685 
Spirulirostra,  685 
Spirulirostrina,  685 
Spisula,  497 
Spondylobolus,  372 
Spondylus,  459 
Spongilla,  51 
Spongiochiton,  513 
Spoiigiomorpha,  106 
Spongiostroma,  124 


SpoTigites,  353 
Spongophyllum,  86 
Sporadoceras,  631 
Sporadopyle,  64 
Sporadosciuia,  66 
Sportella,  488 
Spyridiocrinus,  191 
Spyroceras,  600 
Squama,  745 
Squamularia,  412 
Squilla,  768 
Stachella,  523 
Stacheoceras,  641 
Stachyodes,  124 
Stachyspongia,  59 
Staliola,  545 
Stauranderaster,  251 
Stauria,  87 
Staurocephalus,  725 
Staurocystis,  154 
Stauroderma,  65 
Staurolonche,  42 
Staurosoma,  158 
Stavelia,  463 
Stearnsia,  474 
Stearoceras,  604 
Steganoblastus,  160 
Steganocrinus,  197 
Steganoporella,  351 
Stegerhynchus,  397 
Steinmannites,  648 
Stelidiocrinus,  189 
Stellipora,  334 
StelUporella,  112 
Stellispongia,  70 
Stellocavea,  326 
Stelloria,  99 
Stemmatocrinus,  225 
Stenarcestes,  642 
Stenarthron,  788 
Stenaster,  249 
Stenochirus,  763 
StenocJiisma,  396 
Stenocrinus,  212 
Stenodictya,  796 
Stenogomphus,  810 
Steuoraphalus,  558 
Stenonia,  294 
Stenopoceras,  606 
Stenopora,  335 
Stenosmilia,  101 
Stenotheca,  541 
Stenothyra,  545 
Stephanites,  640 
Stephanoceras,  663 
Stephanocidaris,  273 
Stephanocoenia,  101 
Stephanocrinus,  207 
Stephanophyllia,  105 
Stereocrinus,  191 
Stereopsamniia,  106 
Steueroceras,  669 
Stiboria,  99 
Stichocystis,  152 
Sticliopora,  350 
Stictocella,  346 
Stictopora,  345,  346 
Stictoporella,  345 
Stictoporidra,  346 
Stictoporina,  345 
Stictotrypa,  347 
Stigraatopygus,  290 
Stirechinus,  282 
Stirjmlina,  468 
Stoliczkaria,  121 
Stolleya,  51 
Stolopsyche,  815 
Stolzen  burgiella,  418 
Stomatella,  528 
Stomatia,  528 
Stomatopora,  319,  319 
Stomatopsis,  547 
Stomechinus,  278 
Stonionopneustes,  281 
Stortingoeriiius,  209 
Strabops,  781 


Stramentum,  745 
Straparollina,  527 
StraparoUus,  527 
Strebljtes,  659 
Streblotrypa,  344 
Strenoceras,  665 
Strenuella,  717 
Strephodes,  87 
Strepsidura,  557 
Streptaster,  159 
Streptelasma,  82 
Streptis,  387 
Streptoceras,  611 
Streptocrinus,  221 
Streptorhynchus,  387 
Strepula,  738 
Striatopora,  114 
Stribalocystis,  153 
Stricklandinia,  395 
Strigatella,  560 
Strigilla,  494 
Strigocaris,  751 
Strigoceras,  658 
Stringocephalus,  401 
Strohaeus,  536 
Strobilepsis,  744 
Strobilocystites,  154 
Strobüospongia,  62 
Stroboceras,  604 
Stromatocystis,  159 
Stromatomorpha,  106 
Stromatopora,  123 
Stromatoporella,  124 
Stromatotrypa,  339 
Strombodes,  86 
Strombus,  552 
Strongylocentrotus,  282 
Strophalosia,  391 
Stropheodonta,  385 
Strophiceras,  603 
Strophocheilus,  576 
Strophocrinus,  217 
Strophomena,  386 
Strophonella,  385 
Strophostoma,  540 
Strophostylus,  530 
Strotocrinus,  198 
Strotopora,  330 
Struthiolaria,  552 
Studeria,  290 
Stuorella,  524 
Sturia,  637 
Stylaraea,  112 
Stylaster,  120 
Stylastraea,  98 
Stylaxis,  86 
Stylina,  100 
Styliola,  570 
Stylocoenia,  101 
Stylocora,  97 
Stylocrinus,  209 
Stylodictyon,  124 
Stylohelia,  96 
Stylonurus,  783 
Stylopliora,  96 
Stylophyllopsis,  97 
Stylophyllum,  97 
Stylotrochus,  94 
Styracoteuthis,  683 
Subclymenia,  604 
Subemarginula,  526 
Subulites,  537 
Suecoceras,  595 
Suessia,  413 
Sulcocava,  320 
Sulcuna,  741 
Sunetta,  492 
Supercytis,  323 
Surcula,  563 
Sutneria,  663 
Swantonia,  392 
Sycoceras,  611 
Sycocystites,  154 
Sycum,  559 
Symbathocrinus,  209 
Symphyllia,  99 


Symphysurus,  719 
Symphytocrinus,  239 
Sympterura,  255 
Synaphe,  738 
Synapta,  313 
Syncyclonema,  458 
Syndosmya,  495 
Synerocrinus,  205 
Synhelia,  95 
Synocladia,  342 
Synodontites,  482 
Synopella,  71 
Syntrielasma,  383 
Syntrophia,  392 
Sypharoptera,  807 
Syringoceras,  602 
Syringocrinus,  151 
Syringolites,  114 
Syringopleura,  411 
Syringopora,  116 
Syringosphaeria,  121 
Syringospira,  411 
Syringostroma,  124 
Syringothyris  411 
Syrnola,  537 
Systrophoceras,  601 

Taeniaster,  249 
Taeniodictya,  345 
Taeniopora,  346 
Tagelus,  495 
Tainoceras,  605 
Talarocrinus,  201 
Tanaocrinus,  193 
Tancredia,  484 
Tanysiphon,  494 
Taonurus,  141 
Tapes,  493 
Tarphyceras,  600 
Tarsophlebia,  810 
Tarsopterus,  784 
Tauredon,  804 
Taurinia,  556 
Tauroceras,  453 
Taxocrinus,  205,  206, 
Taxonus,  806 
Tealliocaris,  757 
Technocrinus,  191 
Technophorus,  733 
Tecticavea,  325 
Tectura,  520 
Tectus,  531 
Tegula,  532 
Tegulifera,  391 
Teinostoma,  532 
Telescopium,  550 
Teliocrinus,  197 
Tellidora,  494 
Tellina,  494 
Tellinomya,  440 
Tellinopsis,  439 
Temnechinus,  282 
Temnocheilus,  605 
Temnocidaris,  274 
Temnocrinus,  204 
Temnopleurus,  282 
Temnotropsis,  525 
Tenea,  487 
Tenka,  444 
Tentaculites,  572 
Tenthre<lo,  806 
Terataspsis,  722 
Terebella,  138 
Terebellaria,  325 
Terebellum,  552 
Terebra,  562 
Terebratalia,  406 
Tere-bratella,  408 
Terebratula,  403 
Terebratullna,  404 
Terebratuloidea,  398 
Terebripora,  317 
Terebrirostra,  406 
Teredina,  501 
Teredo,  501 
Teredolltes,  501 


838 

Terquemia,  451 
Tessarolax,  551 
Tethyopsis,  51 
Tetinka,  444 
Tetracamera,  398 
Tetrachela,  762 
Tetracidaris,  274 
Tetnicrinus,  540 
Tetractinella,  418 
Tetracystis,  154 
Tetradella,  738 
Tetragonites,  652 
Tetragonoceras,  606 
Tetragraptus,  129 
Tetrameres,  612 
Tetrameroceras,  612 
Tetramorion,  612 
Tetranota,  522 
Tetrapygus,  281 
Tetraster,  248 
Tetrataxis,  29 
Teiithopsis,  688 
Textularia,  27 
Thais,  558 
Thalamopora,  33,  71 
Thalas.sina,  764 
ThwLdbSsites,  452 
Tlialassoceras,  637 
Thalassocrinus,  238 
Thaleops,  720 
Th'ülocrinus,  199 
Thamnasteria,  103 
Thamnastrea,  103 
Thamniscus,  341 
Thamnodictya,  61 
Thamnophyllum,  84 
Tliamnotrypa,  346 
Thaumastocoelia,  71 
Theca,  571 
Thecidea,  365,  388 
Thecidella,  388 
Thecidiopsis,  388 
Thecidium,  388 
Thecocyathus,  95 
Thecocyrtella,  413 
Thecocystis,  159 
Thecosiphonia,  55 
Thecosrailia,  99 
Thecospira,  419 
Thecostegites,  117 
Theiphusa,  767 
Thenarocrinus,  215 
Theoiioa,  322 
Thetsitea,  552 
Thiara,  547 
Thiemella,  382 
Thiolliericrinus,  234 
Thlipsura,  739 
Tholiasterella,  62,  63 
Tholopora,  326 
Thomasina,  374 
Thomisus,  790 
Thoracoceras,  600 
Thracia,  467 
Thrinoceras  604 
Thrips,  800 
Thurammina,  25 
Thurmannia,  669 
Thyasira,  487 
Thylacocrinus,  189 
TliylaccKles,  547 
Thysanocenis,  652 
Thymnocrinus,  187 
Tliysanodictya,  61 
Thysanopeltis,  720 
Tkysanotus,  371 
Tiaiticrinus,  158 
Tiarechinus,  298 
Tibetites,  635 
Tibtelta,  571 
Ticfiogonia,  463 
Tilesia,  322 
Timanites,  631 
Tindaria,  441 
Tinoporus,  33 
Tirolites,  648 


TEXT -BOOK  OF  PALEONTOLOGY 


Tissotia,  671 
Titanocarcinus,  767 
Tityus,  788 
Tivela,  493 
Tmaegoceras,  655    ' 
Tolypammina,  25 
Tomocheilus,  539 
Tonicella,  513 
Tonicia,  513 
Tonna,  555 
Torellella,  572 
Torinia,  538 
Tormocrinus,  241 
Tornatella,  565 
Tornatellea,  565 
Tornatina,  568 
Tornoceras,  630 
Torynifer,  398 
Torynocriniis,  240 
Toucasia,  477 
Tournoueria,  545 
Toxaster,  294 
Toxometra,  237 
Toxopneustes,  282 
Trachyceras,  648 
Traehydermon,  513 
Trachydomia,  539 
Trcwhynerita,  539 
Tiachyodon,  513 
Trachypora,  114 
Trachysagenites,  639 
Trachyteuthis,  687 
Tragophylloceras,  652 
Trapezium,  472 
Trauvmtocrinus,  225 
Tremabolites,  68 
Tremadictyon,  63 
Trematella,  335 
Trematis,  377 
Trematobolus,  376 
Trematoceras,  604 
Trematocystis,  155 
Treinatodiscus,  604 
Trematonotus,  521 
Trematopora,  339 
Trematopygus,  290 
Trematospira,  414 
Tremopora,  349 
Treposella,  738 
Trepospira,  525 
Tresus,  498 
Tretaspis,  711 
Tretoceras,  609 
Tretospira,  539 
Triacrinus,  208 
Triadosialis,  811 
Triainoceras,  633 
Triarthrus,  715 
Tribachiocrinus,  224 
Tribliocrinus,  191 
Triboloceras,  604 
Trichasteropsis,  249 
Trichites,  446 
Trichiulus,  793 
Trichopteridium,  814 
Tricoelocrinus,  170 
Tridacna,  490 
Triforis,  550 
Trigeria,  401,  414 
Trigondictya,  346 
Trigonella,  406 
Trigonellina,  405 
Trigonia,  467 
Trigonoceras.  604 
Trigonocoelia,  442 
Trigonocrinus,  241 
Trigonocystis,  150 
Trigonodus,  452 
Trigonosemus,  406 
Trigonotarbus,  791 
Trigonotreta,  410 
Trigonulina,  409 
Triloculina,  38 
Trimerella,  373 
Trimeres,  612 
Trimerocephalus,  726 


Trimeroceras,  612 
Trimerocystis,  154 
Trimerus,  724 
Trimorion,  612 
Trinacria,  442 
Trineynacystis,  152 
Trinucleus,  711,  711 
Triodonta,  474 
Triplecia,  387 
Tripleuroceras,  610 
Triplosoba,  808 
Tripneustes,  282 
Triptera,  571 
Tripylus,  296 
Triton,  555 
Tritonalia,  558 
Tritonidea,  556 
Tritoniuvi,  555 
Trivia,  554 
Trochalia,  548 
Trochammina,  26 
Trochamminoides,  26 
Trochiliopora,  326 
Trochiscolithus,  112 
Trochoceras,  605 
Trochocrinus,  194 
Trochocyathus,  94 
Trochocystites,  150 
Trochoderma,  313 
Trocholites,  600 
Trocholitoceras,  600 
Trochonema,  530 
Trochoseris,  102 
Trochosmilia,  99 
Trochotoma,  525 
Trochus,  531 
Troostocrinus,  170 
Tropaeum,  653 
Trophon,  558 
Tropiceltites,  640 
Tropidocaris,  752 
Tropidoleptus,  385 
Tropidomya,  470 
Tropidopora,  344 
Tropites,  638 
Truncaria,  557 
Truncatula,  323 
Truiicatulina,  33 
Tryblidium,  521 
Tschernyschewia,  390 
Tubina,  541 
Tugonia,  499 
Tulotoma,  544 
Turbina,  531 
Turbinaria,  108 
Turbinella,  560 
Turbinilopsis,  539 
TurUnocrinus,  190 
Turbinolia,  94 
Turbo,  528 
Turbonellina,  531 
Turbonilla,  537 
Turbonitella,  539 
Turnus,  501 
Turonia,  55 
Turricula,  560 
Turrilepas,  744 
Turrilites,  654 
Turris,  563 
Turritella,  546 
Turritoma,  525 
Turtonia,  488 
Tuzoia,  750 
Tyleria,  467 
Tylocrinus,  195 
Tylopoma,  544 
Tylopterus,  783 
Tympanotoma,  550 
Typhis,  558 
Tyrbula,  799 


Udora,  761 
Udorella,  761 
Uintacrinus,  236 
Ulangia,  98 


Ulocrinus,  224 
Ulrichia,  738 
Umbonium,  532 
Umbraculum,  568 
Umbrella,  568 
Umbrellina,  321 
Uncinella,  413 
Uncinulina,  398 
Uncinulus,  397 
Uncites,  413 
Undularia,  536 
Ungula,  371 
Ungulina,  487 
Ungulites,  371 
Unicardiuni,  484 
Unicrisia,  318 
Unicytis,  323 
Unio,  454 
Uniocardium,  490 
Unionia,  452 
Unitrypa,  341 
Uperocrinus,  196 
U'phantaenia,  61 
Uranoceras,  608 
Urda,  758 
Urechinus,  294 
Uronectes,  756 
Ussuria,  637 
Uvanilla,  528 
Uvigerina,  31 


Vaginella,  571 
Vaginoceras,  595 
Vaginopora,  353' 
Vaginulina,  30 
Valenciennesia,  573 
Valletia,  478 
Valvata,  544 
Valvatina,  570 
Valvulina,  29 
Vanuxemia,  442 
Vasocrinus,  218 
Vasseuria,  683 
Vasum,  560 
Velates,  534 
Velorita,  474 
Veloritina,  474 
Venericardia,  475 
Venerupis,  494 
Veniella,  472 
Venilicardia,  472 
Ventriculites,  65,  71 
Venus,  492 
Vermetus,  546,  546 
Vermiceras,  655 
Vermicularia,  546 
Verneuilia,  412 
Verruca,  746 
Verrucocoelia,  64 
Verruculina,  |59 
Vertebralina,  39 
Verticordia,  469 
Vertigo,  576 
Vertumnia,  448 
Vesicomya,  491 
Vestinautilus,  604 
Vevoda,  438 
Vexillum,  141 
Vibracella,  351 
Vicarya,  550 
Villorita,  474 
Vincularia,  350 
Vinella,  317 
Virgatites,  664 
Virgularia,  110 
Vitrinella,  532 
Vitulina,  417 
Viviparus,  544 
Vlasta,  438 
Vola,  457 
Volborthella,  597 
Volborthia,  370 
Voluta,  561 
Volutella,  561 
Volutifusus,  561 


INDEX 


839 


Volutilithes,  561 
Volutodernia,  561 
Volutomitra,  500 
Volutomorplia,  561 
Volvai^ia,  566 
Volviceranius,  447 
Volvula,  56S 
VolruUUa,  568 
Vulsella,  449 
Vulsellina,  449 

Waagetiia,  660,  t565 
Waagenoceras,  642 
Waagenupora,  387 
Waclismiithicrinus,  205 
Waehneroceras,  657 
Wakiillina,  461 
Waldheiiaia,  408 
Waltonia,  408 
Waniieria,  714 


Wai)tia,  733 
Watthia,  523 
Welscliia,  658 
Wf'slonia,  .'iTl 
Whiteavesia,  462 
Wliitella,  442 
Wliitfleldia,  415,  416 
Willemoesia,  761 
Williamia,  573 
Wilsoiiia,  398 
Wimanella,  381 
Witcliellia,  660 
Wiwaxia,  137 
Wooclücrimis,  223 
Woitheiiella,  137 
Worthenia,  524 
Wortlieiiopora,  347 

Xantlio,  767 
Xaiithopsis,  767 


Xeiiaspis,  645 
Xenmter,  248 
Xenoeidaris,  274 
Xenocrinus,  193 
Xenodiscus,  645 
Xeiiophora,  543 
Xestoleberis,  739 
Xiphidiocaris,  751 
Xiplioteutliis,  681 
Xylobius,  793 
Xylotrya,  501 

Yolioia,  732 
Yoldia,  441 
Yorkia,  376 

Zacantlioides,  716 
Zaphreiitis,  83 
Zeaerinus,  223 
Zeilleria,  406 


Zellania,  405 
Zemira,  557 
Zenatia,  498 
Zenkericrinus,  190 
Zeuglopleiirus,  282 
Zidona,  561 
Zittelia,  553 
Zittelisiwngia,  68 
Zitteloceras,  603 
Ziziphiniis,  532 
Zonatiila,  326 
Zonopora,  325 
Zoopilu.s,  102 
Zophocrimis,  158 
Zugmeyeria,  403 
Zurcheria,  660 
Zygites,  524 
Zygocriims,  172 
Zygopleura,  537 
i  Zygospira,  408 


END   OF   VOL.    I 


Printed  by  R.  c^  R.  Clark,  Limited,  Edinburgh. 


^ 


J(I195'85 


RETURN  TO  the  circulation  desk  of  any 
University  of  California  Library 
or  to  the 
NORTHERN  REGIONAL  LIBRARY  FACIUTY 
BIdg.  400,  Richmond  Field  Station 
University  of  California 
Richmond,  CA  94804-4698 

ALL  BOOKS  MAY  BE  RECALLED  AFTER  7  DAYS 

•  2-month  loans  may  be  renewed  by  calling 
(510)642-6753 

•  1-year  loans  may  be  recharged  by  bringing 
books  to  NRLF 

•  Renewals  and  recharges  may  be  made  4 
days  prior  to  due  date. 

DUE  AS  STAMPED  BELOW 


:ebi2Z00i 


12,000(11/95) 


Y\\%  00830 


9117 


PHYSICAI 
SCIENCES 
\»BRARY 


-^ 


UNIVERSITY  FARM  LIBRARY 


|:|i|^;:,; 


l^'-^UlV'-