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Full text of "A history of infusorial animalcules, living and fossil .."

D^ 











FORTHE PEOPLE 

FOR. EDVCATION 

FOR SCIENCE 






LIBRARY 

OF 

THE AMERICAN MUSEUM 

OF 

NATURAL HISTORY 





HISTORY 



INFUSORIAL 



ANIMALCULES, 



LIVING AND FOSSIL 



ILLU3TBATED BY 



SEVERAL HUNDRED MAGNIFIED REPRESENTATIONS. 



BY ANDREW PRITCHARD, M.R.I., 

Author of the " Microscopic lllustratious," &c. 



A NEW EDITION, ENLARGED. 



LONDON: 
WIIITTAKER AND CO., 

AVE MARIA LANE. 



1862. 



LIBRARY 

OF THE 

AMSRICAN MUSEUM 

OF 
NATURAL HISTORY 



S. Stkakeu. Printer, 80, Bishopsgatc Street Withiu, Loudon. 



28C83 

OCT 9 '62 



PREFACE. 



In presenting to the public a third volnmc on the 
History of Infusorial Animalcules, I venture to express 
a confident hope that it will prove as acceptable as the 
Editions of 1834 and 1841. 

This Edition has been jointly prepared by J. T. Arltdge, 
M.B. and myself. In it the classification used by Ehrenberg 
in his great Work of 1838, has been retained; whilst 
abstracts of the systems proposed by other naturalists have 
been added and explained. 

The great number of new genera and species (both 
living and fossil) here introduced, necessarily increased the 
•/ bulk of the volume, which has been further augmented by 

doubling the number of Engravings — Graphic Illustrations 
being indispensable to a clear comprehension of the subject. 
These additions, however, have been made without increase 
of cost to the subscribers who have honoured me by their 
confidence. 

I have freely availed myself of the elaborate Avorks of 
Ehrenberg, — the splendid monographs of Kiitzing and Ralfs, 
as well as the valuable researches of Professors Bailey, 
Siebold, Dujardin, Dr. Stein, Mr. Brightwcll, and others. 



iv. PREFACE. 

The original papers in the Annals of Natural History have 
also largely yielded materials. In all cases I have been 
careful to insert the authorities ; and I hope that those 
who may hereafter quote from this volume will be 
equally just. 

The aim has been to form as complete a manual as the 
present state of knowledge will admit ; and I believe that 
it will be found useful, both to the Natiu'alist and to the 
Microscopic Observer. 



Canonbury Lane, 

LONDON, 

24a June, 1852. 



CONTENTS. 



PART I. 

An Introductoky IIistoiiy of Infusorial Animalcules. 

PAcr. 
Section 1 . Localities and appearance of Infusoria in masses , 7 

2. General external forms, coverings, organs and members of 

Infusoria 11 

3. On the eye specks, or visual organs of Infusoria 17 

4. Distinction between Infusoria and other minute Animals and 

Plants 18 

5. Effects of temperature on Infusoria 22 

6. Effects of Air, Chemical Mixtures, and Poisons, on Infusoria 23 

7. Effects of Electricity, Galvanism, and Magnetism, on Infusoria ... 25 

8. On the resuscitation of Infusoria 25 

9 . On the supposed method of manufactui'ing Infusoria 27 

10. On the evolution of light by Infusoria 28 

11. Classification of Infusoria into Polygastrica, Rotatoria, &c 29 

12. On the Polygastrica as a class ; and of their habitats and 

movements 31 

13. On the digestive system of the Polygastrica 34 

14. On the vascular and respiratory systems, and of the secretions 

of Polygastrica 44 

15. On Organs of Sensation in the Polygastrica 46 

16. Reproduction of Polygastrica 48 

17. Of the affinities and classification of Polygastrica 56 

18. Geographical disti'ibution of Polygastrica, their relative abxmd- 

ance, &c 62 

19. Of the Rotatoria as a class ; and of their habitats and movements 65 

20. Of the external coverings, muscular system, and organs of 

locomotion, of Rotatoria 68 

21. Of the digestive system of the Rotatoria 73 

22. Of the vascular and respiratory systems of the Rotatoria 77 

23. Of the organs of sensation and nervous system of Rotatoria. .... 81 

24. Of the reproductive organs, and the reproduction of Rotatoria... 82 

25. Of the affinities and classification of the Rotatoria 86 

26. On showers of Infusorial Animalcules.,. 89 



VI. CONTENTS. 



PART II. 



Ox THE COLLECTING AND PREPARING InTI'SORIAL AnIMALCVLES TOR 

Microscopic examination. 

Page 
Section 1. On the methods of capturing, selecting and placing Infusoria for 

examination under the microscope 93 

2. On microscopes for examining Infusoria 99 

3. On micrometers and the method of measuring Infusoria 1 05 

4. On glass tubes, &c., for taking Infusoria from the water, and 

placing them in the apparatus for examination 106 

5. On the Compressor or Crush Box 106 

6. On viewing Infusoria by polarized light 107 

7. On the method of feeding Infusoria with coloured substances... 108 

8. On the mode of diying and preser-\dng Infusoria 108 

9. On Infusoria contained in flints and semi-opals 110 

10. To prepare fossil Infusoria for the microscope 110 

1 1 . On mounting Infusoria permanently in fluids Ill 

12. To mount Infusoria as opaque objects 113 

PART III. 

Classification and description of Infusorial Animalcules. 

Class 1. Polygastrica 115 

2. Rotatoria GOl 

3. Tardigrada 681 

List of papers on Infusoria, in the Magazine of Natural History 686 

Description of the Engi-avings, plates 1 to 24 688 

Index to the Families and Genera of Infusoria 701 

Abbreviations used in Fart III. 

Agh. for Professor Agardh, of Sweden. 

B. for Professor Bailey, of New York 

Bre for M. de Brebesson, of Falaise, Normandy. 

Duj. for M. Dujardin, a French natui-aUst. 

E. or (Ehr.) for Professor Ehrcnberg, of Berlin. 

Kiitz. or K. for Professor Kiitzing, author of several elaborate works. 

M. for F. 0. Mullcr, the author of the first systematic Ilistory of Animalcules. 

R. for Mr. Ralfs, author of an elaborate monograph on DcsmidiciE. 



NAMES OF SUBSCHIBETIS 

TO THE PRESENT EDITION. 



Rev. R. J. Gould, Windsor. 

C. "Weeks, Esq., Torquay. 

S. Smith, Esq., Wisbcach. 

W. Law, Esq. 

G. Bird, Esq., York. 

W. PengiUy, Es(i., F.G.S., Torquay. 

F. Perkins, Esq. 

J. Ainslic, Esq., Ulverston. 

— Gunton, Esq. 

Rev. R. C. Douglas, Stafford. 

W. H. Dikes, Esq., Wakefield. 

W. C. Bassctt, Esq., Suffolk. 

T. Brightwell, Esq., Norwich. 

W. Brooke, Esq., I^orwich. 

F. Ransome, Esq., Ipswich. 

T. Prothero, Esq. 

J. Aubin, Esq., Jersey. 

Sir Edward Pine Coffin, Bath. 

Mr. Topping. 

R. Wingham, Esq., Norwich. 

Messrs. Longman, & Co. 

Capt. Jones, R.N., M.P., ilimagh. 

E. 0. Spooner, Esq., Dorsetshire. 
Mr. John Gale, Rutlandshire. 
W. Knight, Esq., Demarara. 
Dr. Hamilton. 

London Institution. 

T. Scully, Esq., Clonmel. 

F. C. S. Roper, Esq., F.G.S. 
Edwin Brown Esq., Burton-on-Trent. 
Mr. J. Bond. 

G. H. Kingsley, Esq., M.D,, Cambridge. 
H. U. Janson, Esq., Exeter. 

R. PhiUips, Esfp 

Jas. S. Cobb, Esq., Gt. Yarmouth. 

A. Vincent, Esq., Somerset. 

N. Stowers, Esq. 

A. M'Cann, Esq. 

Rev. W. Read. 

Dr Thos. Wright, Cheshire, 

W. Thompson, Esq. 

Saml. C. Whitbread, Esq. 

Alex. Miu-ray, Esq., L.R.C.S., Barnct. 

John Watson, Escp 

Richard Maysmor, Esq., Devizes. 



NAMES OF SUBSCEIBERS' 



Jonncr, Es(|^., Edinburgh. 

B. Hooke, Esq. 

C. De Castro, Esq., Torquay. 
H. Ludlum, Esq. 

J. B. W. Potts, Esq., M. D., Dorset. 

E. Smallwood, Esq,, York. 
Mr. Highley. 

J. T. Hillier, Esq., Ramsgatc. 

R. Gausby, Esq., Kent. 

Rev. H. Gr. Watkins, Barnct. 

Alfred Burleigh, Esq., Bristol. 

Dr. Ansell. 

R. Mcstayer, Esq. 

Mr. Fairservice. 

Rev. R. Anstice, Hertfordshire. 

Mr. Barnet. 

James Penny, Esq., Dorset. 

Allen Dalzell, Esq., Edinburgh. 

WiUiam Bird Herapath, Esq., M.D., London, M.R.C.S.. Bristol. 

William Lomax, Esq., Bolton-le-moors. 

Rev. J. B. Turner, Hertfordshire. 

Rev. R. Thomas. 

Thomas Pearson, Esq., Yorkshire. 

James Forster, Esq., Dorsetshire, 

Hugh Robert Stump, Esq., Norfolk. 

Antonio Brady, Esq. 

J, Hughes Hemming, Esq., Huntingdonshire. 

W. W. Williams, Esq., Gloucestershire. 

Mr. J. H. Beilby, Birmingham. 

James T. Bell, Esq. 

J. W. Leng, Esq., Yorkshire, 

Messrs. Phillip and Son, Liverpool. 

Jolm Lister, Esq., M.R.C.S., Doncaster. 

Dr. E. W. Pritchard, M.D., M.R.G.S., &c. &c., Yorkshii'o. 

Fitzmaurice Okedeu, Esq., Haverford, West. 

Thomas Spencer Cobbold, Esq., M.D , Edinburgh. 

G. B. Knowles, Esq., F.R.C.S., L.S., &c., Bii-mingham. 

Jolm Wiblire, Esq., Southampton. 

F. Bossey, Esq. 

Rev. W. T, Collins, M.A., F.L.S., and G.S., Somcrsot. 

G. W, Dando, Esq., Liverpool. 

W. H. Griffiths, Esq., M.D., F.L.S. 
W. R. Milner, Esq., Yorkshire. 
Nathaniel Holmes, Esq., Yorkshire, 
(ieorge Frederick Taylor, Esq. 
George (Jolcs, Esq. 
M. A. Holden, Esq. Exeter. 
T. Beauclianqi, Esq., Norfolk. 
Messrs. 1). Willie aud_Sons, Aberdeen, 
J. H. Gibbons, Esq. 
Spcncc Bate, Esq., Swansea. 



PART I. 



AN INTRODUCTORY HISTORY 



OF 



INFUSORIAL ANIMALCULES, 



Among tlie arguments deduciblc from the natural world, in support 
of the existence and superintending providence of an Almighty 
Intelligence, none can carry a stronger conviction home to a reason- 
ing and philosophic mind, than those drawn from that portion of it 
which falls under consideration in the present treatise. Distributed 
everywhere throughout this world, designed and formed by an all- 
wise and gi'acious Creator, serving, were it no other purpose, that of 
evidencing his all-pervading power, exists a race of beiags so dimi- 
nutive, as to have provoked man's utmost ingenuity to bring them 
within the range of his peixjeptivc powers. 

"In the clearest waters, and also in the troubled, strongly acid, 
and salt fluids of the various zones of the earth ; in springs, rivers, 
lakes, and seas ; in the internal moisturo of li\ing plants and 
animal bodies, and, at times, carried about in the vapour and dust 
of the whole atmosphere of the earth, exists a world, by the 



£• QENEBAL niSTOKY OK 

common senses of mankind unpcrccivcd, of very minute living^ 
beings, which have been called, for the last seventy years, Infusokia. 
In the ordinary piu'suits of life, this mysterious and infinite kingdom 
of living creatui'ca is piis&ed by without our knowledge of, or in- 
terest in, its wonders. But, to the quiet observer, how astonishing 
do these become, when he brings to his aid those optical contrivances 
by which his faculty of vision is so much strengthened. In every 
drop of stagnant water, we are generally, if not always, able to 
perceive, by means of the microscope, moving bodies, of from 
l-1150th to 1-25, 000th of an inch in diameter; and which often 
live packed together so closely, that the space between each indivi- 
dual scarcely equals that of their diameter." 

The wisdom and goodness of providence have endowed these 
living creatures with all that can be needed for their happy exist- 
ence. A reference to the drawings, generally, will afford some idea 
of their beautiful and varied forms. "What, for instance, can be 
more admirable in structure than the Infusoria of the family 
Vohocina ? (Sec Plate 1- figs. 34 to 57.) In what class of animals 
are its members so curiously and so sj-mmetrically associated toge- 
ther ? In the Volvocina, innumerable beings are colonized within a 
simple, delicate, crystal-like shell, whose form, sometimes spherical, 
at others quadrangular, presents us with examples of perfect sym- 
metry and proportion. Who can behold these hollow living globes, 
revolving and disporting themselves in their native element, with as 
much liberty and pleasure as the mightiest monster of the deep : — 
and, to carry our views a step further, to speak in detail of series 
of globes, one within another, alike inhabited, and their occupants 
alike participating in the same enjoyment — who can behold such 
evidences of creative wisdom., and not exclaim with the Psalmist, 
" How wonderful arc thy works, Lord, sought out of all them that 
\\dcwc pleasure therein /" 

Again, take an example fi'om the most minute of li\dng beings to 
which our knowledge at present extends, such as the Manas crepu- 
seulum (sec Part III-), and compute the number which could occupy 
the bulk of a single grain of mustard seed, the diameter of which 
does not exceed the tenth of an inch : it is hardly conceivable that 
within that narrow space eight millions of active lining creatures can 



INPUSOniAL ANIMALCULES. -3 

exist, all richly endowed with the organs and faculties (as hereinafter 
fully described) of animal life ! Such, however, is the astonishing 
fact. Again, to take au exaiuple from those families of Infusoria, 
which possess the power of chmying tJieir fonns at pleasure, and yet 
to confine it to the drawings of the first plate (although the second 
would furnish protean phenomena of a more extraordinary character), 
take the figures of the family Astasiaa (groups 68 to 82), and you 
have creatures capable of assuming all the various forms there 
depicted, in the short interval of a few seconds, and that under the 
observer's eye. In the beautiful little creatures of the genus 
Euglena, you maj^ also perceive a distinct vmwl organ, by which they 
can steer their coiu'se with unerring rectitude. Many of the In- 
fusoria do not possess this organ. But, mark the all- wise dispensation 
of Providence in this respect! — those which have it live, for the 
most part, near the surface of the water, whilst those which have it 
not, as the Baeillaria, locate near the bottom This circumstance iu 
their economy has not hitherto been noticed. 

Lastly, — still restricting our observations to the drawings of the 
first plate, look at the graceful forms of the Closterina {fg.63to group 
67), which have long rivetted the attention of the most eminent 
naturalists of modern times, and which long defied all their powers 
of investigation, aided by all the refined and searching means which 
human ingenuity could supply, to determine whether they are 
animals or plants ! 

In short, there is not one species, out of the many hundred 
described in the third part of this work, but offers ample scope for 
the exercise of oux deepest reflection, at the same time that it 
afi'ords an admirable proof of the adaptation and design of Creative 
Wisdom. 

The plan of this work wiU comprehend a description of those 
creatures which arc generally to be found in animal or vegetable 
infusions, and such as agree with them in their general structure 
and habits. Special descriptions of each will be found in Part III. 

In Die Bifusionsthierschen, the author has occasionally introduced 
animals which have been classed imder other divisions of the animal 
kingdom. As examples, we may take the family Dynobryonia, the 
members of which are classed as zoophites by other naturalists. 

B 2 



4 GEKEP.AL HISTOIiT OF 

Again, in the gemif! Bodo, some of the ppociee arc proper Entozoa. 
and, tlicrcfore, ought to be exchided. Having, however, taken that 
work as the basis of my arrangement, all the species described 
therein will be found here. 

With regard to the Spermatozoa of animals, our laiowledgo of 
them is but scanty and confused, arising principally from their 
extreme minuteness, which, even ■s\'ith the assistance of our most 
perfect microscopes, places them at the very limit of our vision. 
The great importance of this subject, especially to the medical pro- 
fessor, has obtained for it, from several distinguished naturalists, 
long and laborious researches ; but, on the whole, the results have 
been conti'adictorj- (see section XTII.) It will be sufficient, therefore, 
to say, that since the time of their disco veiy (1676), up to the 
present period, all that we know of the true Spermatozoa of animals, 
is, that they are not distinguishable from Cercaria, found in the livtr 
of snails, the animal organization of which has been made out by 
Bauer, AYagner, and Elu-cnbcrg. 

The recent discoveries of Dr. Enger on the Spermatozoa of plants 
is a subject of such deep interest, and so little known in this 
country, that I have introduced a description of them under the 
genus Spirillmn ; while original di^awings of them will be found in 
Plate XII. 

It has been said that the line of demarcation between many 
species of animals and plants — the transition from the one kingdom 
to the other — is not easily defined. Indeed, so close is the connec- 
tion between them, that some members of the families Clostei-ina, 
Vibrionia, and Bacillaiia, which are considered by Ehrcnberg to bo 
animals, are, by many eminent botanists, set down as belonging to 
the vegetable kingdom, and classed with the minute aquatic alga; of 
the genera Oscillatoria, Spyrogj-ra, &.c. The true species of the 
two genera just named, it must be admitted, are not of animal 
structure ; and Dr. Ehrcnberg has given us the following reasons 
■why they are not included with the lafusoria : — 1 . They have no 
oral apertm-e. 2. They never propagate by direct self-di\-ision, but 
by the mere dissolution of the gemmrc. 3. They increase in size 
only by the growth of the gemmae. 4. They have both the external 
and internal rigidity of vcgetablo organization. 5. The impregna- 



IKTUSORIAL A:^IMALCriES. <* 

tion of the SpjTogyra resembles that of some of the species of 
rimgi. 6. They derelope acicnlar crystals A\'ilhin themselves, like 
some well-known plants. 7. Their motion is not perceptibly volun- 
tary. (See section IV.) 

For the convenience of reference, it is proposed to divide this part 
into sections; and, although the subjects treated of may not, as 
respects some of them, have received all that careful investigation 
v.hich they deserve, yet it is presumed that sufficient has been done 
to lead the minds of the more curious inquirer to a further research. 
Previous to which, I present the reader with Professor Ehrcnbcrg's 
summary' of the suhject : — 

1. All the Infusoria arc organized, and the greater part of them 
(probably all) ai-e highly organized bodies. 

2. Tlio Infusoria constitute two very natural classes of animals, 
according to their structiu'c, v>'liich classes admit of subdivision, 
npon the same principle. 

3. The existence of the Infusoria in the four quarters of the 
globe, and the Bca, is proved ; as also that of indi\'idual9 of the 
same species in the most opposite ends of the worid. 

4. The geographical distribution of the Infusoria upon the earth 
follows the laws observed regulatbig that of other natural bodies. 

5. Most of the Infusoria are invisible to the nalccd ej-c ; many 
arc visible as moving points ; and the size of the body does not 
exceed, in any case, the l-12th of an inch. 

6. The minute invisible Infusoria, in consequence of tlieir im- 
mense and swarming numbers, colour large tracts of water with 
very remarkable hues. 

7. They give rise to one kind of phosphorescence of the sea, 
though in themselves invisible. 

8. They compose (though singly invisible) a sort of mould, 
tlrrough living m dense and crowded masses. 

9. In a cubic iach of this mould, more than 41,000 millions of 
single animals exist, and constitute, most likely, the chief proportion 
of living bodies upon the face of the earth. 

10. The Infusoria are the most reproductive of organized bodies. 

1 1 . Prom one of the kuo-wu propagative modes of the Infusoria — 
that is, self-division — a continual destruclion, beyond all idea, of the 



6 GENEHAL HISTOET OF 

individual, and a similar interminable preservation and extension of 
it, in air and water, ensues, which, poetically, borders upon eternal 
life and growth. 

12. The copulation of gemmae, which perhaps includes the hitherto 
unsolved poly-embryonate riddle of the seeds of all plants and 
vegetable formations, is solved in the family Clostcrina. 

13. The Infusoria, in consequence of their siliceous shells, form 
indestructible earths, stone, and rocky masses. 

14. With lime and soda we can prepare glass, and swimming 
bricks, out of invisible animalcules ; use them as flints ; probably 
prepare iron from them ; and use the m&untain meal, composed of 
them, as food in hunger. 

15. The invisible Infusoria are sometimes hurtful, by causing the 
death offish in ponds, deterioration of clear water, and bogg}^ smells; 
but not, as has been supposed, in giving rise to malaria, plague, and 
other maladies. 

IG. The Infusoria appear to be (as far as is yet known) sleepless. 

17. The Infusoria partly break up (zcrfliesscn) by egg laying, 
[ind thereby undergo, passively, various changes of form. 

18. The Infusoria form invisible intestinal worms in many animals, 
and in man, even if the Spermatozoa are excluded from amongst 
them. 

19. The microscopic Infusoria have, also, themselves, internal and 
external parasites. 

20. The Infusoria possess a comparatively long life. 

21. As the pollen of the Pine falls yearly from the clouds, in the 
fonn of sulphur-rain, so do the much smaller animalcules appear 
(from being passively elevated with the watery vapour) floating in a 
live state in the atmosphere, and sometimes, perhaps, mixed with 
the dust. 

22. In general, the Infusoria maintain themselves pretty uniformly 
against all external influences, as do larger organized bodies. It is 
true that they sometimes consume strong poisons \sdthout immediate 
injury, but not without an after effect. 

23. The weight of the invisible Infusoria, light as it is, is yet 
calculable, and the most gentle current of air or diaught can pluy 
with their bodies as with the vapour of water. 



INFTTSOniAL ANIMALCULES. 7 

24. The c-vidcnt and preat quickness of the motion of Infnsoria, is 
reducible as follows: ITijdatina scnta, moves l-12tli of an inch in 
four seconds; 3Ionas punctum, the same in forty-eight seconds ; while 
Navicida gracilis, takes six-minutes twenty-four seconds to progress 
the same distance. 

25. Linneus said, omnis calx e vermihus : — either to maintain or 
deny omnis silex omne ferrumve vermihis, would be, at the present 
moment, imjust. 

26. The direct observations, as yet kno-mi, upon the theory of 
generatio primitiva, are wanting in necessary strictness. Those 
observers, who profess to have seen the sudden origin of the minutest 
Infusoria from elementary substances, have quite overlooked the 
compound structure of these organic bodies. 

27. The frequent wonderful changes of form of many Infusoria 
arc yet to have their limits, and the laws governing them defined. 

28. The power of infusorial organization is instinctively shown by 
the strong chewing apparatus, with teeth, which they possess, and 
their exhibition, likewise, of a complete mental activity. 

29. The study of the Infusoria has led to a more distinct and con- 
clusive notion of animal organization generally, and the limits which 
circumscribe the animal form ; from which all plants and minerals, 
that want the animal organic system, are strongly and distinctly 
separated. 

30. Finally, — it results from these inquiries, that experience 
shows an unfathomableness of organic creations, when attention is 
directed to the smallest space, as it docs of stars, when reverting to 
the most immense. 

Section I. — Localities and Appearance of Infusoria in Masses. — In 
investigating most branches of practical science, especially those 
relating to Natural History, the subjects to which our observations 
are to be directed are generally difficult of attainment, and the 
inquiry cannot be prosecuted without considerable inconvenience. 
Tliis, however, is not the case Avith respect to the Infusorial Animal- 
cules. We can examine them in our chamber, at any leisure moment, 
and at any time or season , and Ave can procure them, at least the 
ordinary kinds, such as the Paramecium, Iiolpoda, kc, with the 
utmost lacilitv, — for thcv abound in muist waters wherein the stalks 



3 GEyEEAL niSTOET OF 

of flowers have boon a few days steeped — wliilst many of the morc- 
bcaiitiful kindS; such, as the Vohocina, Astasiaa, Uydatincca, &.c., arc- 
to be found in pools of clear standing water. 

Many remai'kable species, and some of the most elegant I have 
ever examined, have been taken in meadow-trenches, in the slowly 
rimniug water, after a summer shower, and especially about the 
pei'iod that the first crop of hay was mown. Among healthy water 
I)lonts, such as the Chara, Ceratophyllum, Confervto, Lemna, &c., 
the various kinds of Vorticellina and Rotatoria, may bo sought for 
with success. The stems of aquatic plants, particidarly those of the 
description just mentioned, have often the appearance, to the naked 
eyo, of being encased with mouldiness or miicor, wliich, on being 
examined under the microscope, proves to be an extensive colony of 
arborescent animalcules. AVhenever this appearance is of a blueish 
milky hue, the species will mostly be those of the Vorticella or 
Ji!pisti/lts. (See the Engravings.) If you observe little dark bristle- 
like bodies standing out among the stems, you may expect them to 
be the Melicerta ; and the little ycUow gelatinous balls upon the 
Ceratophyllum are, probably, the McgalatrocTxa. In clear shallow 
pools, the Volvox glohator (Jig. 55) may be met with in vast numbers 
in the spring of the year ; and, when these are found amongst 
Lemna, by examining them under a deep magnifying power, you 
may often discover, ■uithin theu- hollow spheres, the Notommata 
parasita, like so many white specks. The dust-like stratum we fre- 
quently notice on the surface of stagnant ponds, is often composed 
almost entirely of species of the most bcautilul colours, such as the 
Muglena, Chlorogonimn, Pandorina, Gonium, and Bursaria. The thin 
shining film, which sometimes covers plants in pools of water, 
assuming the varied hues of red, brown, yellow, green, and blue, is 
also made up of Infusorial Animalcules. For example — those 
objects, which under water appear to be coated with a thick green 
matter, aboimd with the different species of tho Euadra and 
Closterium, or with the Artkrodesmus quadricaudatus and A.2)cetinatus, 
the Stcntor polgmorphus, and Vorticella cJiIorostigma ; and those 
objects which have a bright orange-coloured coating, derive it from 
the presence of the Stentor aureus. 

The abode of animalculea is not, however, confined to the clear 



INFL'SOBIAL ANIMALCULES. V 

fresh water of Lakes, rivers, pools, springs, and trenches, bnt extends 
even to tlic briny ocean, to strong acids, tannin, and the fluids con- 
tained in the animal and vegetable creation. In moist earth, the 
species of Bacillaria and other shelled animalcules may also be 
found ; and even the very air wo breath o may teem mth them and 
their germs, whilst the gentlest breeze will bo sufficient to waft 
them in myriads over the distant waters, and to diffuse these living 
atoms over the face of jSTatui-e. So that, in short, whether wo 
descend into the deepest mines, where darkness ever reigns, or climb 
the loftiest mountains, whoso summits glow with almost perpetual 
simshine, there shall wo find them located alike. 

Although the colouring of water is sometimes derived from the 
oxides of iron and other mineral or earthy substances, over which it 
flows, or from the Oseillatoria and other minute Algoo which it con- 
tains, an intensity of colouring will also be given it by the presence 
of Infusorial Animalcules. Thus the Astasia imparts a blood-red 
coloTU", as also the Euglena rtiber ; the Gallionella, Navicicla, and 
Gomphonema, impart an ochreous hue. Blue proceeds from the 
Stentor ceruleus. Masses of water assume an intense green from 
Monas hicolor, TTvella hodo, Glenomonwi tingens, Phacelovionas pulviscuhcs, 
Cryptomonas glauca, Cryptoglcna conica, Pandorina morum, Gonium 
pcctorahj Chlamidomonas pulvismlus, Volvox glohator, Astasia and 
Euglena sanguinea, when young ; Euglena viridis, Chlorogonium 
euchlorum, and Ophrydium versatile; yellow from the Astasia 
jlavicans ; a milky tint from the Polytoma uvella, and Ophryoglena 
atra, when they are numerous. 

The rapid and mysterious transition of colour, occasionally ob- 
servable in lakes, and which has often created an alarm in the timid 
minds of the superstitious inhabitants on their borders, the micros- 
cope has shewn to arise from certain changes in the condition of 
Infusoiia. Thus, a lake of clear transparent water will assume a 
green colour in the course of a day ; nay, more, it will become 
coloured and turbid in the middle of the day, when the sun brings 
these creatures to the surface, and rapidly devolopos them, or causes 
their dead bodies to ascend, whilst in the morning and evening, it 
will a "lain be clear. 



10 GENEEAL HISTORY OF 

The phosphorescence of the sea appears to be occasioned, in many 
instances, by the presence of animalcules, which, although indi- 
vidually imperceptible, often render luminous many miles of water 
by the immensity of their numbers. 

In the same manner, large arborescent figures, resembling Fuel 
and Alg«, are formed by the Micromcga ; and masses of great 
extent by Ejnstylis and Schizonema. 

The Bacillaria or their shell-like siliceous coverings, (loricaj) are 
largely concerned in the formation of the earth's crust, entering 
extensively, sometimes, almost exclusively, into the structure of 
large sections of the earth's strata, especially those of the tertiary 
period. The character of the rock so constituted, will vary accor- 
ding to the nature of the associated earths, whether argillaceous, 
siliceous, or calcareous. Thus, we have evidence of the existence of 
Infusorial life in the earliest eras of the globe ; and what is still 
more curious, we find species existing at those remote epochs, still 
represented in the existing fauna. Nor are instances of such enor- 
mous accumulations of these minute beings, as to build up land 
from the sea-bottom, wanting, even at the present day. For in- 
stance, we learn from Sm J. Ross, and other explorers of the 
Antarctic Ocean, that the water between the parallels of 60° and 80° 
south latitude, is of a pale ochrous brown colour from the cnoiinous 
number of microscopic Liatomacea, and that the death and decompo- 
sition of these same beings produce a submarine deposit or bank of 
vast dimensions, occupying an area of 400 miles long by 120 Vvdde, 
and flanking the whole length of Victoria Barrier. — (Dr. J. D. 
Hooker, Report British Association, 1847.) 

Among other almost unlooked for localities of Infusoria are 
meteoric dust, and other similar substances, precipitated from the 
atmosphere. In such matters, Ehrenberg has discovered siliceous 
loricaj chiefly belonging to the family Bacillaria (Section XXVI.) 
together with the calcareous shells of the Phytolitharia. Volcanic 
ashes even furnish specimens of Infusoria, and the same great 
microscopist has also intei-prcted the nature of the mai-veUous blood- 
like spots, wliich, much to the horror of the ignorant and supersti- 
tious, have occasionally ax)peared suddenly on bread and other 



INFUSOEIAI ANIMALCULES. 11 

farinaceous substances ; he having sliown that such stains arc due to 
the astonishingly rapid development of a monad, therefore called the 
Monas procUgiosa. — (See Berlin Transactions for 1847). 

We should not omit to mention a very common mistake with 
respect to seeking after Infusoria. Some persons imagine that if 
they procure a portion of fetid ditch water, or take a few flowers, 
and immerse them in a flower glass full of water, they will be fur- 
nished in a few days with aU the varieties they may desire ; the 
fact, however, is very different from this. It is true, that in such 
cases, Infusoria will be found, but they Avill be only of the most 
ordinary kinds. Those of high interest, either as regards their 
structure, form, or colour, Uke all the other master- works of Nature 
and of Natui-e's God, are not so easily attained. Some degree of 
skill must be exercised for the purpose. But as we shall fully 
explain this matter in the section on the method of procuring and 
selecting Infusoria, we need not proceed further with the subject 
here. 

Section. II. — General External Forms, Coverings, Organs, and 
Members of Infusoria. — Before entering on the classification of Infu- 
sorial Animalcules, as determined by their internal structure, it will 
be well to make a few remarks upon their general appearance and 
external characters, as exhibited by the microscope. The forms and 
members of large animals may be said, in one respect, to differ but 
Httle from each other ; the comparative anatomist being enabled to 
trace, by easy gradations, one common type throughout the whole, 
the varieties being occasioned by a greater development of certain 
parts, and the suppression of others. Such, however, is not the 
case with Infusoria. The general forms of Infusoria will be best 
conceived by a reference to the drawings, inasmuch as words would 
be found insufficient to convey an idea of the vast varieties which 
they assume. Some are egg-shaped ; others resemble spheres ; 
others, again, different kinds of fruit, eels, serpents, and many 
orders of the invertebrated animals, funnels, tops, cylinders, pitchers, 
wheels, flasks, Sec, &c. 

The covering, or outer tunic, of Infusoria, is of two kinds; the 
one soft and apparently membranous, yielding to the slightest 
pressure, and accommodating itsulf to the state of repletion or other- 



12 OENEBAL HISTORY OF 

wise of tlio animalcule, and thus resembling tlic hmic of the naked 
Mollusca and Annelida, as elugs, Iceclies, Ike. ; the other, stiff, rigid, 
and hard, ha\Tng the appearance of a shell, though, from its flexi- 
bility and transparent natiu-e, it is more like horn. The creatures 
possessing the former of these arc tei-mcd the naked, shell-loss, or 
illoricated Infusoria, whilst those invested with the latter constitute 
the Im^icated. I shall, therefore, adopt the terms loricated and Uhri- 
cated in this work, because they appeal' to be the least objectionable; 
for, although, in etymological strictness, lorica simply means a shell, 
yet, as we commonly attach the idea of a certain composition to the 
word shell, it may be as well to avoid the use of it. 

In the doubtful organisms which form the large family Bacinaria, 
the botanist employs the terms frustide, froud, and valve for the outer 
coveiiug of those they consider vegetables. The reader will, there- 
fore, bear in mind these several words, and is referred to the general 
remarks on that family and its sections given tn cxtcnso in Part III. 

The Lorica differs greatly as to its composition ia different genera. 
In some cases it is composed entirely of silica ; in others, of lime, 
combined with carbonic acid as a carbonate, with a portion of the 
oxide of ii'on. In some, it is destructible by heat, in others, not so. 
There is a difference also as to the proportion of the creature enclosed 
within the lorica. Some Infusoria are entirely encased, as in a box 
or pitcher; whilst others are only so in part, having merely a shield 
or carapace over them. "Wliere the lorica encloses the animal, save 
its head and tail, as does the covering of the tortoise, it is called a 
testa or testula ; when it covers the back only, a sadclUmn or shield, 
as in Euplotcs, Aspidisca, Sec. The term JJrceolus applies to a gelati- 
nous membranous or more firm external investment, having a bell- 
glass, cyliudrical or conical figure closed at the posterior, but open at 
the opposite exti'cmity, whence the animal may protrude itself. This 
variety of lorica is met with in the genera Bijjlugia, Binolryon, Vagi- 
nicola, and Floscularia. The appellation Laccrna, or mantle, is applied 
generally to the gelatinous external membrane of the bodies of In- 
fusoria, iacre^iBing with their increase ia size. Within this tunic the 
animal may reproduce itself, and, for a certain time, the parent and 
offspring possess it in common, but id'tcr a time the mantle ruptures 
and the yoxmg escape- Thu?, at a certain period, the ] 



TNrrSOEIAL ANIMALCULES. 13 

individual existence, and is traneformcd into a simple cnpsiilc. Thi3 
organization is met with only in tho rolygastrica and more particu- 
larly in tlie genera Vohox, Eudorina, Pandorina, and Gonium. 

"Where a lorica exists it may be made up of two or more separable 
segments, called valves, when of two, it is said to be bivalved ; when 
of more multivalved. The valvular form of lorica is chiefly met with 
in the gi-eat family Bacillaria, and it is such lorica that more particu- 
larly present a seidptiu-cd surface, and have been employed by 
microscopists as tests (sec family BaciUaria, Part III). Some lorica 
are also furnished with appendages, or processes, projecting in the 
foiTu of si)ines or knobs from theu' surface. 

As, in verj' minute genera, it is often difficult to ascertain, by mere 
inspection, whether they arc enclosed within a lorica or not, it will 
not be deemed uninteresting to point out the manner in which this 
may be determined. Having obtained some specimens of the Infu- 
soria, we will suppose of the family Cryptomonas {fgs. 21 to 33), 
place a di'op of water containing them in an aquatic live-box, com- 
pressor, or crush-box, mixing a httle colouring matter with the water, 
according to the directions given in the section " On feeding Animal- 
cules with coloured Materials,^'' when, if loricated, a clear transparent 
ring will be observed, encircling the animalcules, and keeping them 
separate from the fluid in which they are immersed. Should this 
test, however, bo deemed imsatisfactory, press down the cover of the 
aquatic live-box, so as to crush the specimens, when the colom^ed 
fluid will enter and suiTound their bodies, and by a proper manage- 
ment of the illumination of the microscope, the broken edges of the 
lorica wiU be \'isible, as seen mfig. 33, which is a representation of 
the Trachclomonas volvocina, similarly circumstanced. 

Until recently, many of the genera of tho smaller kinds of ani- 
malcules were supposed to be devoid of any external organs whatever; 
but the feeding on coloured substances, and the introduction of 
achromatic glasses, have proved the incorrectness of this conclusion, 
even as respects the Monads. The simplest external member, observ- 
able in the Infusoria, is a single, delicate, hair-like filament, differing 
much in length, situate near tho oral orifice or mouth, whence it has 
been designated the 2>i'ohoscis. When tliis member is of an imiforni 



14 GENERAL niSTOEV OF 

appearance, it is said to be filiform, or thread-like; but, when it 
tapers toward the extremity, like an eye-lash, or cilium, it is called 
flafjelliform. This organ is used by the animalcule both for locomotive 
and purveying pxu'poscs. When the creature is in rapid motion 
through the water, this instrument is seen to act as an oar or paddle, 
in facilitating a progressive movement, whilst, at the same time, a 
current is created in the direction of its mouth, providing for the 
prehension of food. This member is not easily seen, inasmuch as 
considerable skill in the use of the microscope is requu'cd to show it, 
nor will even that, in all cases, suffice. The emplojoncnt of finely- 
divided indigo or carmine, and the use of stops or diaphrag-ms imder 
the object in the microscope, afford the surest proof of its existence. 
When, by these means, its action has been detected, allow the water 
to evaporate, and you may notice a streak or mark, as it diics, left 
upon the glass, thus giving conclusive evidence of the presence of 
this organ. Sometimes the mouth is furnished with two of these 
proboscidcs, or cilia, nearly of eq^ual length with_^the bodj', as in the 
genus Chhrogonmm. 

When these cilia are disposed in clusters, as with some of the 
larger polygastric animalcules, their structure may be more correctly 
ascertained. In the family Oxytrichina (see Engraving), the different 
modifications of these filiform organs constitute excellent character- 
istics of the genera. 

Cilia may be described as hairs seated apparently upon a bulb. 
They perform a rapid vibratory motion, the point of each describing 
a comparatively large circle, whilst the base merely turns round upon 
its articulating surface, or part of the bulb to which it is affixed. 
Ehrenberg is of opinion that there are two kinds of cilia, viz. Cilia 
continua, in which the bulb is a continuation, or merely enlarged 
termination of each cilium ; and Cilia a/rticulata, in which there is a 
joint or articulation of the cilium to the bulb. Examples of the 
former may be observed in the Stylonycliia mytiliis ; and of the latter 
in the Paramecium aurelia {fig. 330). Cilia in tlieii' arrangement are 
either separate and independent, or combined, forming in the latter 
case the rotary organ of the Rotatoria. In the first or simple form 
which exists in Polygastrica, the ciHa are usually set round the mouth, 



INFUSOIilAL AJJIMALCULES. 15 

or spread over the body generally, in which case they arc often dis- 
posed in regular rows, as in Paramecmm, Opliryorjlena, and Urohptus, 
{vide figs. 329-334). 

It may be remarked here, that naturalists have been greatly 
di^dded in opinion with respect to the functions performed by the 
cilia, more especially those belonging to the Rotatoria. It has been 
contended hy some, that these organs form the chief instrument for 
respiration ; nor is it at all improbable that such is the case, as we 
find that similar ones are placed round the gills or beard of the oyster, 
muscle, &c., to produce currents in the water, and bring a fresh 
supply to the creatui-es. The disposition of the bimdles or clusters 
of cilia in the Rotatoria, and theii- appearance when in motion, may 
be considered as one of the most interesting and curious spectacles in 
the animal creation. Their strong resemblance to toothed-Avheels, 
and their seeming continual revolution, have been most fertile sub- 
jects for the exercise of the imagination ; indeed, there are few, if 
any other phenomena, which can excite more astonishment in the 
beholder. Let the reader turn to the various plates representing the 
Rotatoria, and mark the great variety'' of design, and exquisite beauty 
of execution, there displayed in the forms and disposition of these 
wheel-like organs, and his mind can hardly be restrained from revert- 
ing, in the profoundest admiration, to that Divine Intelligence by 
which such wonders could alone have been called into existence. 

Setcc, or bristles, are a kind of rigid hairs or cilia, used as organs 
for the support of the body, and for climbing, but without having 
the power of vibrating like real cilia. These organs are sometimes 
devoid of the thickened base or articulation, as in the genus 
Actino^ihrys {fig. 266) ; whilst others possess a true articulation, as 
exemplified in the posterior three of the Stylonychia mytilm. Some 
are (awl-shaped) suhulate ; others have a knob at the extremity, and 
hence termed capitate. 

Styles are tliick straight seta3, usually seated on the under side of 
the body, projecting backwards like the tail feathers of birds. These 
never vibrate ; neither have they a bulbous base, nor are their ex- 
tremities bent or hooked. They are used for the support of the 
body, and for climbing, and are capable of more extended motion 
than setce. 



16 GENERAL HISTOET OF 

Uncini arc curved hook-like processes, like thick short hair?. 
They emanate from the imcler siirface of the body, and in office 
resemble the feet of larger animals. These organs do not vibrate, 
have neither bulb nor articulation, but sometimes possess considerable 
latitude of motion, not serving however for locomotion, but only for 
prehension. 

Tarialle processes are another description of external members, 
which perform the function of locomotion ia a very complete manner. 
In the family Amoehaea, the animalcule appears to have the power 
of protruding, at pleasure, any portion of its body, to form these 
processes; a property which has not inaptly obtained for it the 
designation of protean. In the loricated family Ai'cclKna, the variable 
processes are definite, the protrusion being restricted to those parts of 
the body which are situated about the opening in the shell, designed 
for that purpose. These processes, like the protean ones, are soft or 
membranous, and resemble, though on a email scale, those of the 
Mollusca, of which the horns of the common snail are a familiar 
example. The Infusoria, however, have a greater command than the 
snails, &c., over these processes, and a more extended action, in pro- 
portion to their size. 

In the Infusoria of higher organization, such as the Rotatoria, 
there are definite processes, of a toe or claw-like description, which 
are mainly used as organs of attachment. ,Thesc are generally at 
the extremity of a certain prolongation of the body, which may be 
designated a foot-like member. To the inexperienced observer, this 
process has generally been supposed to be the tail ; but, not being 
placed dorsaUy, with respect to the discharging orifice, it must be 
considered as occupjTng the position of the foot. In these creatures, 
there is a large development also of those parts of the body to which 
the rotatory organs are attached ; and, in the case were two only of 
these organs are seen, a projection may be noticed on each side of the 
anterior portion of the animalcule, which has been termed an eur : 
For example, sec Jig. 41 G. 

Other appendages of Rotatoria, imconnectcd with locomotion, are 
Horns fCorniculaJ Cirrhi and spines fCalcares.J The first occur as 
elongated, fleshy, and rather firm projecting points, covering either 
the entire body, as in Philodina aculcata, or only some portion of it, 



INFUSOEIAL ANIMALCULES. 17 

as the so-called tail iu the genera Rotifer, actinunis, &c. The secoud 
variety of processes are longer and stronger than bristles fsetcejy 
rather resembling the tentacles of Entomostraca. Ehrenbcrg has 
only instanced such in the genera Triarthra. The spur presents the 
form of a short reti'actile stjde projecting from the neck. The 
existence of sucking discs (patella), at the end of the tails or foot- 
like organs of some Infusoria, as at the extremity of the stalks of 
vorticelkB, and also on the tails of some Rotatoria, has been observed 
by Ehi'enberg. 

Sectiox III. — Of the Eye Species, or Visual Organs of Infusoria. — 
Oui' knowledge of the existence of these organs is whoUy attributable 
to the invention of the achi'omatic microscope. In F. 0. Miiller's 
work, which contains drawings of the larger number of the animal- 
cules, lately figured by Ehrenberg, and several of them made with 
much exactness, though on a very small scale, there is not one of the 
Polygasti'ica represented as possessing a visual organ, and but one 
species of the Rotatoria, in which he considered the existence of it 
established. By referring to the engravings, however, it will be 
seen that nearly all the Rotatoria have eye-specks, and that many of 
the genera of the Polygastrica are also furnished with them. If no 
other proof than this could be obtained, therefore, of the existence 
of a nervous system in these animated atoms, this might still be 
taken as a sufficient evidence of the fact. 

One of the smallest, and appai-ently the simplest of the genera of 
Infusoria, in which the eye is perceived, is Ilicroglena, in which, as 
in the greater number of cases, the coloiu' or j)igment is red. 

By taking a glance at the tabular distribution of the genera of 
each family, as given after the general remarks on each, in Part III., 
in this work. The reader wiU notice, at once, that nimibers of the 
genera of the Polygastrica are furnished with one eye-speck ; and, 
in some cases, which however are more rare, with two. (See 
Section XY.) 

In the Rotatoria, the number and position of these organs may be 
regarded as excellent characteristics of the genera. In the gi'eater 
proportion of these, the animalcules have two, and, in some instances, 
three eyes ; whilst, in one genus, Theortis, as many as seven or eight 
have been distinctly recog-nized on each side of the head. "When the 

c 



18 GENEEAL HISTORY OF 

eye-specks are situated in front of the oesophageal bulb, to wliich 
the teeth are attached, they are termed frontal eyes ; and when 
behind this bulb, cervical eyes. They are sometimes disposed in a 
line, side by side, as in Triopthalmm ; at others aiTangcd triangularly, 
as in Eosphora ; in Cycloglena they foiTQ a cii'cle, and in Theorus a 
cluster on each side. 

Ehi'enberg ha\Tng discovered the existence of eyes under the form 
of red specks in Rotaioria, argued from analogy the visual character 
of the similarly colonized specks in the Polygastrica. Recent accui'ate 
observations made on the eye-specks of Rotatoria (see section XXIII), 
prove that they are distinctly defined, have an investing capsule, and, 
in the words of M. Yalenciennes, (Sur les embranchments inferieui's 
des Annehdos, Ann. des Sciences Nat. 1850), have a crystal! i tie lens, 
and, consequently, the essential attributes of visual organs. On the 
contrary, owing to the extreme minuteness of the Polygastric Ani- 
malcules, all appearance of definite outline is wanting in the red 
specks of Polygastrica, and resemblances of them being foimd in the 
reproductive germs of Algae, many observers do not admit the visual 
nature of these red specks. 

Section IV. — Distinction letween Infusoria and other Minute Animals 
and Plants. — In our present state of knowledge, "with respect to 
organic bodies, there are many diificiilties in the way of determining 
on such boundaries as may reduce them to weU defined groups. Even 
the line of demarcation between animals and plants, which, at first 
sight, might be supposed to be so veiy broad and distinct, upon a 
more minute consideration, is not easily settled. Nor is this sm'- 
prising, for if we turn to inorganic nature, we find the chemist is 
equally at a loss to separate the two grand classes into which he 
divides those bodies : namely, — ^metals and non-metallic substances. 
"While, at starting, they offer no resemblance, yet, by slight gradations, 
the bodies of each division approach the other where characters are 
still wanting to distinguish them. As examples, we may take the 
metal Silicium, which is sometimes regarded as a non-metallic body; 
while, on the other side. Iodine and Bromine resemble metals. In 
the organic world, no difiiculty is found in separating the mammals, 
birds, and fishes, from forest trees and floweiing plants ; but, as we 
descend in each kingdom, the Unes of demarcation become less strong 



INFTJSOBIAI ANIMALCULES. 19- 

and decisive, until at length no single chai-acter is sufficient to dis- 
tinguish them. Thus, motion, digestive structiu-e, composition, the 
products evolved, &c., taken singly, are of little avail in separating 
an animal from a vegetable organism. Eecent reseai'ches have rather . 
increased these difficulties. The fashion of the present day is to 
magnify the argoments in favour of vegetable life and physical- 
motions, while those on the side of an animal existence, are slm'ed 
over. It is, therefore, desirable to pause before offering an opinion, 
especially when every distinction hitherto proposed, is seen to vanish 
if rigorously tested. The organisms of a doubtful animal nature, are 
principally found in the families Ilonaditia, Vibrionia, and Jiacillaria, 
which are fully described in Part III. 

1 . Motion. Tliis is an excellent animal character, where its volimtary 
and spontaneous nature can be clearly perceived, but in microscopic . 
bodies, vision being obtained by one eye only, and that imder unusual, 
conditions, difficulties present themselves which do not occur in 
common ^dsion. Again, the germs, or spores of minute Algae, and 
other vegetable organisms, swim about in water until they find a 
proper place for attachment, when they grow as a plant ; hence some 
natiu'alists have supposed that animal Life is ti'ansformed iato vegeta- 
ble, as the name zoospores implies. (See Vibrionia). The mollecular 
motions of Dr. R. Browne — namely, those seen imder a deep magnifier 
in a drop of water, in which fiaely divided gamboge or other organic 
substances have been triturated ; these motions have been compared 
with the spermazoa of animals and plants, which are now considered 
as physical motions only. The circulation or cyclosis in plants, so 
well exhibited in the Chara, have been compared with the motions in 
the Closterina and Bacillaria (see Part III), and hence they are only 
allowed a vegetable Ufe. (See M. Thuret on the Zoospores of Algae, 
Ann. des Sciences Nat. Sieme series Tom XIV., 1850.) 

2. Cilia. The presence of these organs for locomotion, is a strong 
argument in favour of the animal nature of an organism, but alone 
are insufficient, as the minute spores of some Algae possess them. 

3. Digestive Organs. The presence of a stomach would strongly 
tend to the establishment of an animal, but plants have been dis- 
covered which possess a cavity for admitting water, and thus re- 
sembling a digestive sac in its simplest form. While if imbibition 

c 2 



20 GENERAL HISTORY OF 

by the cuticle be admitted, the cells of plants approximate very 
closely to animals. The difRculties, however, are greatest in the 
Besmidiacea and JDiamomacea, to which the reader is referred to for 
particulars. 

4. Composition. Tertiary compounds are claimed for the vegetable, 
but the Chlamidomonas, whose animal nature is undoubted, is only a 
tertiaiy compoimd. The presence of nitrogen was, sometime since, 
excluded from the vegetable, but it is now known that several plants 
contain azote. 

5. Starch. The existence of the organic proximate element, 
Starch, has been much insisted upon as detennining this question, 
i:ideed its almost constant presence in plants, renders it a desirable 
test ; but, in the doubtful animal organism, their minuteness and 
the nature of their coverings, render it difficult of application ; 
indeed, in those cases where it is most needed, as the Desmidiece (which 
see) it too often gives equivalent results. 

6. Hie evolution of Carhonic Acid hj Animals and of Oxygen hj 
Plants, has been proposed for detennining tliis point, but the Euglena 
mridis, whose animal nature is admitted exhales oxygen, as do some 
of the doubtful family BacUlaria and the Yolvox globator, the latter, 
however, has lately been claimed by the botanist. 

7. Visual Organs. The existence of eyes would prove, beyond doubt, 
the animal nature of an organism ; but the red points considered as 
eyes, which exist in many of the Polygastric Infusoria, are, by some 
naturalists, not admitted as eyes, similar red spots being observed in 
the spores of Alg?e, are adduced as confirmatory of this position. 

8. Contractihility has been proposed as a test. It applies only to 
the soft bodied forms, but M. Thuret says it is not peculiar to animals, 
but partaken also by the zoospores of Algae. 

9. Multiplication hj s2)ontaneous division or fission. This method of 
increase has been adduced by Elirenberg, as evidence of the animal 
nature of the Bacillaria and other Infusoria, but, it is admitted, that 
the fissiparous division of vegetable cells is of a similar nature. 
(See Section XVI.) 

10. The non-occurrence of development by conjugation, has been 
latterly insisted ujion as scparatmg animals from plants, but this 
distinction is now questioned. (See Desmedca, Part III.) 



INFUSORIAL ANIMALCULES. 21 

The action of acetic, acid and of electricity, on these minute 
organisms, have been proposed as tests, but hitherto the results have 
been unsatisfactory. 

This imcertairity in distinguishing plants from animals, coupled 
with the observation of some peculiiu" phenomena in the production 
of spores in the lower Alga?, led those distinguished naturalists, 
linger and Kiitzing, and others, to believe iu the transition of some 
foims, from an animal to a vegetable existence, or vice versa. It 
seemed to Kiitziag, that there are beings in which animal and 
vegetable life ai-e so iutimatcly blended, that the kind of exist- 
ence manifested, will depend on the predominance of one or of 
the other, and this too, without a necessaiy change of form. 
Uuger goes fiu'ther in liis belief in the transformations of Algae 
into animals, and the reverse; but, Siebold declares "such an 
opinion is unphilosophical ; for, be the natiu'e of any being what 
it may, vegetable or animal, A^'e must consider it fixed and un- 
changeable. Moreover, the apjiearances on which Unger's views 
rested, ai'e easily understood when we recognize the presence of 
cilia in both animals and plants, a fact, that natiu'alists overlooked. 
(Dissertatio de fiaiibus inter reguum animale et vegetabile constitu- 
endis, Erlangse 1844.") 

M. Thm'et says the error of belicAdng in the metamorphosis of 
Alg£e, has arisen from the confbim.ding together aggregations of 
globules of similar appearance, but of very different natiu-e, — as, 
Infusoria, Zoospores of Algfe, Spores of Mosses, Gonidia of Lichens, 
«&;c. ; a confusion which has led some to suppose that an Algte can 
produce not only another of a species or even germs different to 
itself; but also give origin to a Moss, Hepatica, or Lichen, according 
to the circimistanccs luider which the germ was placed. " For my 
part, I never was witness of any such marvellous transformations. I 
have never seen a Binclmis produce an Algae, nor an Algae a true 
Diselmis. On the contrai'y, whenever I have had the opportvmity of 
following, for a sufficiently long time, the germination of a zoospore, 
I have seen produced, not an Algae of another species, still less a Moss 
or a Linchen, but an individual evidently belonging to the same 
species as the parent plant." 



22 



GENKRAt HISTORY OF 



At another place he wiites, " the germination or extension of the 
zoospore into a tissue similar to that of the parent plant, appears to 
me a good character to distinguish those bodies from Infusoria. Still 
one cannot discover in this phenomenon the basis of a division 
between the lower forms of the two kingdoms ; for vegetables occu- 
pj-ing the lowest grade in the scries of Algae — ex. the ISTostoclimeae, 
Palmelleae, &c., seem to have no other mode of reproduction than 
spontaneous division analagous to that of the most simple animals." 

Section V. Effects of Tcmperatiire on Infusoria. — As \itality in 
these creatures is not destroyed by the ordinary cold of winter, most 
of the common Polygastrica may be found at that season in ponds 
under the ice. The Vorticella microstoma will live after being ex- 
posed to 8° of Fah., and the ice gradually thawed ; although the 
munber in this case may not exceed one in a hundred. Below this 
temperatm-e they A\dll not survive. The same may be said of the 
Monas termo and M. spirillum, the Paramecium aurelia, Cyclidixim 
glaucoma, Glaucoma scintillans, and Kol/poda cucullus. "When Inftisoria 
are destroyed by the cold, no rupture or injuiy will be apparent on 
their bodies, excepting with the Chilodon cucullus, and some few 
others, which, under these circumstances, will often become dissi- 
pated. The Stcntor polymorphus and Mullcri will not live many 
hours in a temperature of 9*^ Fah. ; and arborescent Vorticella, when 
subjected to that degree of cold, fall from the stalks and die. 

The Rotatorial animalcules cannot endure such low temperatures 
as those above named. 

When a small quantity of water, having animalcules in it, becomes 
frozen, and is placed under a microscope, in a cold situation, 
Ehrenberg states that if the ice be clear, each animalcule or group 
will evidently be surroimded by an exceedingly small portion of 
water, which that naturalist supposes to be occasioned by the superior 
temperature or animal heat of the creatures preventing congelation ; 
and he is of opinion, that in all cases where this portion of the water 
freezes, the animalcule necessarily dies. 

If the water containing polygastric Infusoria be gradually raised 
to a temperature of even 125* of Fah., these creatures -wt-U Mve ; 
and Dr. E. obsei-ves, that some of the Chlamidomonas pulvisculus 



INFUSORIAL ANIMALCULES. 23 

existed, on one occasion, in ^\'ater at 200*^ of Fall. If the increase 
of temperature be sudden, the animalcules die at 140'^, notwith- 
standing it be kept up for only half a minute. 

Some animalcules, however, discover an appropriate habital in hot 
springs, and to such, consequently, we may suppose a high tempera- 
tiu'e necessary. 

M. Doyere, by numerous experiments made with Rotatoria, Tardi- 
grada, and AnguiUulce, has proved that those animals when put into 
hot water at 212" Fah. were killed outright, but they retained the 
power of re^-ival, when the water was at llS'^to 118°. When dried, 
individuals were subjected to a heat of 216'', 252°, and even 261°, 
some were found which were capable of being revived. 

Some Vilriones, which Focke discovered in milk, when frozen and 
again thawed, continued to live, and even when they had been dried 
for three weeks, revived on being moistened. 

Focke has mentioned that Pandorina morum, and other probosci- 
dated monads, appear to change very much in colour according to 
temperature and season. (See Reports Zoology : Ray Society, 1841). 

Section VI. — Effects of Air, Chemical Mixtures, and Poisons on 
Infusoria. — That animalcules, Uke eveiy other part of the animal 
creation, continually require fresh supplies of atmospheric au- for 
their support, may be deduced from a variety of experiments. If a 
thin pellicle of oil be spread over the sirfface of the water in which 
they are contained, they very soon die from exhaustion ; and, indeed, 
it must have often hajipened to those who are in the habit of col- 
lecting Infusoria, that when the cork has been left, by accident, too 
long in a phial full of water, they have experienced tliis mishap. 
This is especially the case with respect to the large Rotatoria : 
whenever experiments have been made with these creatures under 
an exhausted receiver, the result has invariably been that vitality 
ceases soon after the air has been expelled. Ehrenberg states, that 
they exist much longer in an atmosphere of nitrogen than in carbonic 
acid or hydi'ogcn. The vapoiu' of sulphur soon puts a period to their 
existence. 

Poisons, which only mix mechanically with water, do not appear 
to affect them materially, but those which are soluble, or combine 
chemically with it, speedily destroy their lives. Many of the Infa- 



24 



GENERAL HISTORY OF 



soria can accommodate themselves to different fluids, provided that 
the transition be not too sudden. Thns, similar species may be 
found in rivers, at their soiu'ce, where the water is perfectly fresh, 
and at theii* very mouths, or junction with the salt water of the 
ocean. Hydatinea have been fed upon powdered rhubarb without 
being sensibly affected by it ; nor does calomel or corrosive sublimate 
kill them ; at least they live some time after these have been mixed 
with the water. Strychnia causes instant death. 

Mr. Addison states that liquor potassse, produces on the smaller 
forms of the Polygastric animals, "the same effect as it does on the 
colourless blood and pus-corpuscles of mammalia ; it peneti'ates the 
transparent integument of the animalcule by imbibition, and causes 
it to burst open and discharge its contents, which have the same 
appearance as the molecules and granides, from the colourless blood 
and pus-corpuscles. 

In the larger forms of the polygastric animalcules, the large 
vesicles or cells (called stomachs) veiy visible in their interior, are 
all discharged fr'om the bodies of the creatiu'es in the same way, 
when submitted to the action of liquor potassae. Thepc so-called 
stomachs may be seen enlarging in the interior of the animalcule, 
prior to the rupture of the external integument ; and when they are 
discharged from the body of the animalcule, numerous minute mole- 
cules may be noticed within them. 

If the Paramecium aurelia be subjected to the action of a dilute 
solution of the alkali, in the proportion of half a drachm (Brandish's 
solution) to an ounce and a half or two oimces of water, it imme- 
diately commences a labom-ed rotatory wriggling motion thi'ough the 
liquid, and in many of the individuals, two remai'kablc vesicles will 
be seen tensely distended in the interior of the animalcule, very 
frequently accompanied with three, four, or five, perfectly ti'anspa- 
rent large cii-cular globules, projecting from the body of the creature. 
After a short period the contents of the body may ])e seen dischai'ging 
themselves into one or more of these transparent projections, while 
the body itself, or rather the integument of the body, may be seen 
to sluivel up, the motionless cilia fi-inging its circumference remain- 
ing very visible." (On the sacculi of the Polygastrica, Annals of 
Natural Histoiy, vol. 12, 1843, p. 101.) . 



INFUSORIAL ANIMALCULES. 25 

These facts have been urged against the animal nature of the poly- 
gastric Infusoria, but, in fairness, it amounts to verj- little, as it is 
well laiown that some species of Acari will live in strong acetic 
acid, and spiders have fed upon sulphate of zinc, therefore, if the 
argument is worth anything, spiders and acari are plants, which 
is absui-d. 

Inferences di'awn fi'om the habits of the higher animals should be 
made with great caution, as the diiferenees between them and 
microscopic organisms are so great. 

SECTioif VII. — Effects of Electricity, Galmnism, and Magnetism, on 
Infusoria. — All the experiments on record, ^hich have been made 
upon animalcules with these powerful agents, appear to me to have 
been conducted without a due regard ha^dng been paid to their dimi- 
nutive size ; and hence, as might be expected, the results have 
proved fatal to their existence. We have, therefore, yet to learn 
what effects might be produced under proj^er modifications. To 
render this proposition more intelligible, suppose, for instance, that 
we wished to ascertain the temperature in which fish would live, 
we should not expect to arrive at the desii-ed information by plimgiug 
them suddenly into boiling water. Dr. E. has remarked that a 
shock from a ley den jar, charged with twenty sparks from an Elec- 
troi)horus, having a resiaous plate seven and a half inches square, 
and a collector five and a half inches, suddenly killed the Volvox 
glolator, Stentor niger and S. aureus, Ampileptus moniliger, Chalimido- 
monas and Euglena viridis. The bodies of the Ophryoglena atra and 
Stentor polymorplms were entirely dissipated by it, and also those of 
the Eyistylis ftavicans, after having been first thrown from their stalks. 
It generally rcquii-cd two such shocks to kill the Paramecium aurelia. 
"When the electrical ciu-rent passes near, and not thi'ough them, 
their movements appear to be unsteady, in the same manner as when 
the mental faculties ia the larger animals are disturbed. Electricity, 
slowly produced, has a more powerful effect than when it is accom- 
panied with rapid sparks. If water, containing animalcules, be 
placed between the poles of a galvanic battery, so as to be decomposed, 
of course, the creatures die ; and a like termination will be occasioned 
by magnetic ciurents. 

Section YIII. — On the Resuscitation of Infusoria. — In almost all 



26 GENEHAL HISTORY OF 

ages of the world there has been evinced a restless desire within us 
to pry into the nature or principle of life, and the precise conditions 
on which it is retained ; and, notAvithstanding that our bodies, its 
present abiding place, are confessedly frail and perishable, the un- 
ravelling of an invisible and immaterial agent has been sought for by 
a reference to them. Hence, each succeeding generation has occupied 
itself in proving the fallacy of preceding theories on this mysterious 
subject, and in forming new ones of its own. Even in modem 
times we have been told that dead matter, under certain circum- 
stances, becomes spontaneously alive, as, for instance, horse-hair 
under water, &c. Too true it is, however, that, let our researches be 
what they may, unless our views are directed upwards to a higher 
|)rinciple than anything that we can argue upon, in what we see 
around us, our laboiirs must end in nought but " vanity and vexa- 
tion of spirit." 

What, perhaps, has tended to awaken owe inquisitiveness on this 
subject, more than anything else, has been that death-like condition 
of torpor, or siispended animation, in which human beings and other 
animals have been known to remain for a great length of time, 
dm'ing which the body is motionless, and apparently unsustained by 
any nourishment whatever. In 1701, Leiiwenhoek observed this 
phenomenon in the Rotatorial Infusoria ; and to such an extent did 
his observations lead him, that he declares they were capable of 
being removed from their native element, dried and preserved in this 
condition for months, and even years, and then resuscitated on being 
again moistened with water. That Rotatoria will revive, after re- 
maining a day or two, apparently in a dry state, I have particidarly 
mentioned in the Natural History of Animalcules. The distinguished 
author of Die Infusionstierchen, after many illustrations and com- 
parisons made "wath reference to this subject, affirms, that wherever 
these creatures are completely dessicated, life can never again be 
restored. In this respect, they exactly correspond with animals of a 
larger kind ; like them, for a time, they may continue in a lethargic 
and motionless condition, but, as it is well known, there wiU be 
going on, within them, a consumption, or wasting away of the body, 
equivalent to so much outward nouiishmcnt as would be needed for 
the sustcntation of life. 



INFUSORIAL ANIMALCULES. 27 

In some recent experiments, Ehronberg has observed, that living 
siliceous Infusoria form a sort of moist earth, (humus) and need a 
very small quantity of water to sustain life ; and that even when 
such humus was let diy fifteen days, a great number still remained 
alive, and became very active on being inti'oduced into a drop of 
water. If the earth was perfectly dried, they died outright, becoming 
incapable of revivification. 

According to M. Doyere's experiments (Ray Society, 1841) Rota- 
toria may be completely dried in pure sand, in the open air, in dry 
air, and in a vacuum, without losing the capability of being revived 
by moistiu'e. 

Section IX. — On the Siqyposed Metliod of Manufacturing Infusoria. 
— "Within the last few years an idea has been prevalent, and many 
persons have occupied themselves in endeavouring to realize so extra- 
ordinary a discovery, that animal life may be produced by means of 
galvanism. The creatures said to have been thus brought into exist- 
ence, that have come under my observation, were neither the most 
minute, nor the most simple, in organization ; and evidently 
belonged to the class Acari. That many scientific men should be 
more than sceptical upon this point, cannot be wondered at ; and 
were it not that the notion originated with, and the experiments 
have been conducted by, one who holds a most honourable position 
amongst us, it would not have been entertained for a moment. That 
some mistake exists with respect to communicatiag vitality to matter, 
by this means, there cannot be a doubt. 

It is not surprising that Linneus, with the imjierfect microscopes 
of his day, should mistake Infusorial Animalcules for minute drops 
of oil in the water; but that Dutrochet, so late as 1833, should 
publish to the world that aU the globular and elliptical Infusoria 
were vesicles set in motion by streams of electricity, and therefore 
could be artificially produced, is but another exemplification of the 
fact, that men of the most distinguished talents in one department 
of science may form very eiToneous notions on others, especially 
where long contiimed observations, and very acciu-ate perceptions, 
are indispensable for arriving at right conclusions respecting them. 

In 1834, Cagniard Latour made a public declaration, that he had 
manufactured animalcules by the aid of carburetted hydrogen. This 



28 GENERAL HISTORY OF 

assertion led to an examination, subsequently, of the creatures, by 
M. Audouin, who ascertained them to be a species of the Entomostraca, 
and who did not hesitate to pronounce the method, by which they 
were said to have been produced, to be fallacious. 

The most ingenious experiment on the imaginary production of 
Infusoria, is that of Professor Bonsdorff, which he communicated to 
the German JSTatiu^alists' Association in 1834. The following is 
Ehi'enberg's account of it : — " If a solution of chloride of aluminimi 
be ch'opped into a solution of potassa, by the attenuate precipitation 
and solution of the alimiinum in the excess of alkali, an appeai-ance 
will be given to the di'op of aluminated matter, by the chemical 
changes and reactions which take place, as if the Amoeba diffluens 
(see description. Part III.) were actually present, both as to its form 
and evolutions, and it ^vill seem to be alive. Such appearance is 
considered, by its able discoverer, as bearing the same relationshiii to 
the real animalcule, as a doU or a figiu'e, moved by mechanism, does to 
a living cliild." 

Section X. — On the Evolution of Lujlit hj Infusoria. — Several small 
animals are known to emit light, apparently j^hosphorescent, as the 
female glow-worm, and some species of the Myriapoda, which I have 
frequently noticed in the gravel walks of a garden, on a dark 
autumnal evening. This emission of light, whether in the above- 
named animals, or in Infusoria, is evidently the result of a vital 
process. In the latter class of creatures, it seems like a single spark, 
of a moment's duration, but capable of being repeated at short 
intervals. That this light is electi-ical, analogy would lead us to 
infer ; as experiments made upon larger creatures have proved it to 
be such with them. 

The phosphorescence of the sea is not unfrequently due, in a great 
measure, to Infusoria, chiefly belonging to the family Cyclidina ; and 
when we take into consideration the minuteness of these creatures, 
the largest not exceeding the 100th part of an inch, whilst some of 
them are scarcely one-twelfth of that size, our ideas of computation 
are too limited to foi-m any just notion of the number which some- 
times illuminates many miles in extent of the ocean's surface. 

Ehrenberg found, at Wismar on the Baltic, that the Peridinium 
tripos and P. fnscus belonged to the phosphorescent Infusoria, and 



INFUSORIAL ANIMALCULES. 29 

further, that the emission of light was restricted to some only of 
these. Those indi^-icll^als which were not phosphorescent were quite 
clear, whilst those which emitted light were filled with yellowish 
brown matter, which he considered to be developed ovaries, so that 
here also the development of light would appear connected with that 
of the ova. 

In his paper on the Infusoria of the Chalk, (1840), that observer 
also stated that one of the most remarkable facts elicited in the course 
of his examination of the sea water, whilst in a state of phosjiho- 
rescencc, was, the presence of several species of two genera, the 
members of which have siliceous loricse, which are abimdant, not 
only in the chalk marls of Caltanisetta, Sicily, Oran, Zante, and 
Greece, but are those forms which, fi'om the incalculable number of 
their very minute lorica?, compose the chief portion of the marls, 
which depend for their origin on the remains of species of Infusoria ; 
and fiu'ther, that they belong to genera, species of which had not 
then been seen in the living state. 

Section XI. — Classiftcation of Infusoria. — Among the various 
an-angements proposed for the distribution of animalcules by dif- 
ferent natiu-alists — and we have not a few, as the minuteness of 
these creatures, and the imperfections of oiu* microscopes, until 
lately, allowed ample field for the imagination to run wild — two 
appear to me to merit particular notice, and these, it is worthy of 
remark, are the productions of men who have laboiu-ed for years in 
making actual observations on them. The fii'st is by 0. F. Midler, 
whose posthumous work, entitled Animalcula Infusoria Fluviatilia et 
Marina, appeared in the year 1786. On tliis arrangement is founded 
my Natural History of Animalcules, prepared in 1832; between 
these two periods the additions to this branch of natural history, 
fi'om actual observation, was not veiy gi-eat ; indeed, until the latter 
work appeared, this subject could not be said to have assumed a 
definite character, and was lui known to the English reader. 

The laborious and long-continued observations of Prof. Ehrenberg, 
in Germany, have enabled him, after several revisions and amend- 
ments, to present us with a classification, which, in my opinion, will 
remain as long oiu" standard, on this subject, as that of Midler has 
been. It is ciu-ious, however, to observe, that in all the publica- 



3(> GENEEAL HISTOBY OF 

tions, up to the present day (in England at least), professing to give 
on account of Dr. E.'s classification, his older, and I may say, 
abandoned systems, have alone been presented. 

Ehrenberg, in his great work entitled Die Infusionsthierchen, has 
not devoted much space in defining the Infusoria, or in. giving a 
general view of the subject ; but he commences almost immediately 
with their systematic arrangement; hence the Third Part of this 
work will give the reader some idea of the general character of that 
splendid volume ; though the design of the two differing, namely, the 
latter being a work of reference, this a manual, many alterations, 
omissions, and additions have been made, especially in the present 
edition ; hence it will be alike unjust to that distinguished natu- 
ralist, as to myself, to consider the one a mere abstract of the other. 

Should the reader possess a copy of my first distinct work on this 
subject — the NftturallTtsiori/ of Aninialciiles, and will make a general 
comparison between the system adopted in that work, and that in 
the present, he cannot fail to observe that, although the principles 
of classification of Mviller and Ehrenberg are widely different, yet 
many of the groups occupy similar positions in the two systems. 
This coincidence is especially striking in the case of the Vibrio of 
Miiller and the BacUlaria of Ehrenberg, and also between the com- 
mencing and concluding genera in each arrangement. 

To proceed : Professor Ehrenberg di^ddes the Infusoria into two 
gi-and classes — the Polygastrica and the Rotatoria : the fonner so- 
called by reason of the fimetion of digestion, being carried on by 
numerous globular vesicles, or stomachs, whilst the latter, like most 
higher animals, have only one stomach. 

Each class is again subdi\"ided into families and genera, which are 
presented ia a tabular form; and further details concerning the 
grouping of the Pohjgastrica, by Ehrenberg, are given in the section 
devoted to the consideration of theh* classification. 

Based as the system of Ehrenberg is, on a particiilar hypothesis of 
the organization of Infusoria, of coiu-se it can be accepted only by 
those who subscribe to that hj-pothesis. Hence Siebold, Dujardin, 
and others, who cannot accept the polygastric sti'ucture as a fact, 
seek for some arrangement in accordance with their own ^iews of 
animalcular organization (see Section XIII.) 



INFUSORIAL ANIMALCULES. 31 

One great change agreed upon by those who dissent from the 
Berlin Professor, is the cxchision of the DesimidiecG and JDiatomece 
from the true animalcules, and the elevation of the Rotatoria to a 
position in the animal scale much higher than the so-called Polygas- 
trica, with which their elaborate organization forbids theii' associa- 
tion imdcr the common name of Infusoria. 

In the classification appended, proposed by Siebold (Section XVII.) 
it will be seen that the term Infusoria is restricted to animals 
evidently moved by cilia, whereby not only the Bacillaria, but also 
those animalcules moving by variable processes under the title of 
Rhizopodes, ai-e separated from Infusoria. In Dujardin's system, the 
Rhizopoda are, however, classed -wdth Infusoria. 

Section XII. — Of the Polygastrica, as a class, and of their hahitats 
emd movetnmts. — Though some portions of the system of classification 
devised by Ehrenberg are certainly objectionable, I still feel that an 
arrangement is yet to be discovered that Tvill supersede it. 

In the opinion of the great Berlin naturalist, the Polygastrica con- 
stitute a natm'al group of animals, and are as satisfactorily distinguished 
as any other class. In this \dew, no other naturalist entirely coin- 
cides : almost all exclude the Bacillaria and Closterina (f. e. the 
BiatomecB and Besmidiem) from the Polygastrica ; many go still 
fui'ther, and declare this class to be a collection of heterogeneous 
beings, many of which do not even belong to the animal kingdom. 
Thus, M. Agassiz says (Annals of Xatiu-al History, vol vi, 1850, p. 
156), ''Eecent investigations, upon the so-called Anentera, have 
satisfactorily shown, in my opinion and in that of most competent 
obseiwers, that this tj-pe of Ehrenberg' s Polygastrica, without gastric 
cavities, and without an alimentary tube, are really plants belonging 
to the order of Algae in the widest extension of this group ; whUe 
most of the monad tribe are merely moveable germs of various kinds 

of other Algae. As for the Enter odela most of them, far from 

being perfect animals, are only germs in an early stage of development. 
The family of Vorticella exhibits so close a relation with the Bryozoa 
(cilio brachiate polj-jies), and especially with the genus PedicelUna, 
that I have no doubt that wherever Bryozoa should be placed, Vorti- 
cella should follow, and be ranked in the same division with them. 

The last group of Infusoria, Bursaria, Paramecium, and the like, 



32 GENERAL HISTOEY OF 

are, as I have satisfied myself by direct investigation, germs of fresh 
water worms, some of which I have seen hatched from eggs of 
Planaria laid under my eyes." Mr. Girard coincides with Agassiz 
in these statements, and adds that the Kolpoda cucullus is one of the 
embryonic stages of a species of freshwater Planaria. (Proceedings 
of American Association, 1848, p. 402). 

jN'one of the Pohjgastrica exceed in dimensions the 12th of an 
inch, and some of the smaller species, as those of Monas, Bodo, Bac- 
terium, and Vibrio, even when full grown, are bnt the 1 -2000th part 
of that measiu'e ; indeed, so minnte must be many of the yoimg of 
these Inftisoria, that they cannot be recognized by our microscopes. 
The genera Stentor and Spirostotmmi on the other hand, contain 
species as large as the gi'eater wheel animalcules (Rotatoria), and are 
easily detected by the naked eye. Again, others, individually so 
small as to be almost in^-isible, fonn, when aggregated, green, red, 
yellow, blue, brown, and black-coloured masses of great extent. 
Thus, the clusters of some species in the families Vorticella and 
Bacillaria increase to such an extent that they attain a size of several 
inches, resembling Pol3'pi. 

The greater number of animalcules belonging to this class are 
found in fresh water ; numbers inhabit the salt water of the ocean ; 
and some live in astringent solutions, even those containing much 
tannin. They also exist in fluids produced by animal secretions ; 
moist earth, too, is another situation in which some are to be foimd. 
As an instance of the later habitat, there has been recently found 
some earth near jS'ewcastle almost entirely composed of living 
species of the genus Bacillaria, and other loricated Infusoria. 
Various kinds reside in the vapoiu- of the atmosphere, in which, 
fi'om then- light weight, they rise in coimtless multitudes, and are 
blown about by the wind in invisible cloud-like masses. 

The degree of motion possessed by the several genera of Pohjgas- 
trica, varies greatly, whilst the sort of movement is as various. In 
soA'cral instances these peculiarities in locomotion are useful in 
characterizing genera ; such will be found particularly indicated in 
the third or systematic part of this work. Some genera are attached, 
and still enjoy some extent of relative movement, such are Vorticella, 
Zooihamnium, and Syncdra. Most of those miattachcd arc, more or 



INFFSORTAt ANIMAtCTTtES. 33 

less locomotive ; but, especially in the family Bacilhria, there are 
manj' motionless genera. In Volvox we see a rolling motion, often 
very lively ; in Bodo and Colcjjs a leaping movement, very active ; 
in Amceha and Bifflncjia, a crawling, most nearly resembling that of 
snails ; in Styhnychia, Euplotes, and Rimantophorm, a creeping, by 
means of uncini, or bristle-like cilia, like that of insects ; whilst in 
very many there is a eimple gliding or swimming motion, in some, 
accompanied by rotation on their axis, and in others, of greater 
relative length, by writhing or serpentine movements ; these last 
varieties are illustrated in Paramecium, Uroleptus, Trachelocerca, La- 
crymaria. Lencophrys, Stentor, Spirostomum, &c. In very minute 
forms, as the Vihrionia, their movements are visible, as scintillations 
in the containing fluid. 

Generally speaking, in all the Polyyastrica, with the exception of 
i^& Pseudopoda, — those with soft * variable processes,^ and the Closterina 
and BacilJaria {Destnidiece and Biatome<e), the property of movement 
is conferred by cilia, or by varieties of them called proboscides, or by 
stiff processes — uncini, &c (see Section II.) but in none ai'e found 
ti'ue jointed locomotive members. 

Prof. Owen remarks, in his Lectures on the Comparative Anatomy 
and Physiology of the Invertebrated Animals, 1843, p. 19, " If you 
watch the motions of the Polygastric Infusoria, you will perceive 
that they avoid obstacles to their progress; rarely jostle one another; 
yet it is difficult to detect any definite cause or object of their move- 
ments." Further on, he wi'ites : " The motions of the Polygastrica 
have appeai'ed to me, long watching them for indications of volition, 
to be in general of the natiu'e of respiratory acts, rather than attempts 
to obtain food or avoid danger. Very seldom can they be construed 
as voluntary, btit seem rather to be automatic ; governed by the 
influence of stimuli -within or without the body, not felt, but re- 
flected upon the contractile fibre ; and, therefore, are motions which 
never tire. We may thus explain the fact which Ehrenberg relates 
— not without an expression of surprise — namely, that at whatever 
period of the night he examined the living Infusoria, he invariably 
found them moving as actively as in the day time ; in short, it seemed 
to him that these little beings never slept." 

The power of locomotion may be for a time possessed by Infusoria,. 



31 GENERAL HISTOET OF 

which, as a rule, are attached ; for example, Stentor and VorticeUa, 
as also many of the doubtfal Infusoria — the Bacillaria, which, 
becoming free, enjoy a slow swimming movement. Perhaps the 
moat interesting example of movement by contractility, is that seen 
in the stalk or pedicle of the genus VorticeUa, in which its activity 
is so great, and its character so peculiar, that it leaves no doubt of 
the presence of muscular fibre and muscular irritability. 

The circular arrangement of very distinct cilia about the upper 
end — head and mouth, in VorticeUa, Stentm', &c., and the whirling, 
wheel -like motion of those ciUa, would seem, as Prof. Owen remarks, 
" to indicate the passage to the higher or rotiferous group." 

Sectioi^' XIII. On the Digestive System of the Pohjgastrica. — The 
microscopic observer, having procured a number of animalcules, will 
not fail to observe within the interior of many a number of cii'cular 
spots ; these are often very large in proportion to the size of the 
creature, and if the water is clear, they appear more transparent 
than the other parts of the animalcule. These vesicles the reader 
may readily distinguish iu many of the drawings contained in the 
first six plates, and part of the seventh, which represent animals of 
the class Pohjgastrica. Like any other division of natural bodies, 
some of the members composing it, exhibit the essential characteristics 
of the class more prominently than others, — thus the genera 
Kolpoda and Paramecium contain the largest forms in which these 
vesicles exist. The reader will do well to refer to the di-awings of 
these genera, which he can readily do by means of the List of 
figures at the end of the volume. 

The older naturalists considered these vesicles as the ova ; and 
Baron Gleichen made many experiments to endeavour to see their 
expulsion, but without success. This idea of the Baron's, respecting^ 
the nature of these bodies is the more remarkable, as it is to him we 
owe the original expeiiments of feeding animalcules with coloured 
food ; and the fact of these parts becoming immediately coloured, 
while the surrounding portions remain transjjarent, could scai'cely 
have escaped his notice. 

From the observations of Dr. E., these globidar vesicles appear 
to be distinct stomachs, of which a single animalcule belonging to 
this class possesses many, as noticed in another place. When one of 



iNFrSOniAT, ANIMALCTTT.tiS. S-T 

these stomach-cells, or eacs, has been filled with coloured food, and 
its situation carefully noted, in a short time the coloiu-ed spot will 
have changed its locality, and hence some naturalists will not admit 
of sei^arate and distinct sacs or cavities, but maintain that the in- 
terior of the creatiu-e is one large digestive cavity, and that the 
globular mass of coloiu-ed particles has merely changed its position. 
To this objection. Dr. E. remarks, that he has distinctly observed a 
Bac to fill, and then the particles to pass singly into another, and so 
on, until the nutritive portions having been imbibed by each cell in 
succession, the refuse is expelled by the animalcule. That few 
observers have noticed this process, is not remarkable, as it requires 
stedfast and incessant observation of a particular animalcule for some 
time, while a contraction of them, or a turning upon their axis, may 
mislead, or even a slight pressui-e or other injury loosening these 
cells, may occasion a volxintary change of place. Another objection 
to their being sepai'ate sacs or cells for the purpose of digestion is, 
that observers have not seen the canal or tube connecting them toge- 
ther ; this Dr. E. admits is the case in many species, owing to its 
extreme tenuity. Also, that from its peculiar office, namely, the 
transmission of the food from one cell to another only, like the 
oesophagus in large animals, the tube possesses a contractile action, 
60 that the difficulty of detection is augmented. Dr. E. affirms he 
has distinctly seen theii' canals while the food has been passing from 
one stomach cell to another ; and in all his works, except Die 
InfmionthiercJien, has presented us with drawings of them, and the 
manner in which they connect all the cells together. Eor observa- 
tions of this kind, it wiU be advisable to select a large specimen of 
either of the following species: — Chilodon cucullus, Trachelius Ovum, 
Vorticella chlorostigma, or V. convallaria, Opercularia articulata, or 
Stylonyckia Mytilus. 

Again, the position of the discharging orifice has favoui'ed the 
erroneous supposition of the excluded substance being ova, for this 
orifice is not situated in any certain relation to the mouth ; for 
sometimes one orifice is common to both purposes, as in the fresh 
water Polj-pe, and some other large creatures. In other Polygastricaf 
it is either situated anteriorly, posteriorly, or laterally, and this again 
may be either on the superior or inferior side. On this charactet^ 

3) 2 



36 GENERAL HISTORY OF 

Dr. E. has foiindcd the subdivision of the class into families, as given 
in Part III. of this work. 

Anxious to lay before the reader an impartial statement of this 
question, I shall, before proceeding with any general remarks on the 
Polygastrica, introduce here translations of the observations of a most 
distinguished German botanist, and likewise those of a celebrated 
French natiu^alist, wliile those of other naturalists relating to par- 
ticular families, are inserted under those divisions. 

Prof. P. J. Meyen writes : — " All naturalists are aware that 
Gleichen, in 1781, tried to make certain Infusoria eat carmine, and 
observed next day that they had several large red granules in the 
interior of their bodies. He thence concluded that they had swallowed 
the colouring matter. He likewise noticed that these coloured 
granules afterwards made their escape by another opening. Gleichen 
has figured these red granules very accurately ; each of them is in 
the centre of a particular circle, the nature of which he does not 
explain. At a later period, M. Ehi-enberg made the same remark, 
and he thence concludes that the Infusoria have several stomachs, 
which, in one section, are destitute of an intestinal canal, while in 
others they not only possess canals, by which they commiinicate with 
each other, but lateral appendages, which besides terminate in a 
coceum. In consequence of these discoveries, these Infusoria were 
designated by the name of Polygastric animals. M Ehi-enberg be- 
lieves that he has proved that their stomachs are filled one after 
another, and he has figured, more or less completely, the intestines 
which fonn the commvmication between the different stomachs. 

" Many observers have abeady questioned these assertions of 
M. Ehi'cnberg (see the memoir of M. Dujardin, on this subject, in 
the tenth volume of the Annates des Sciences Naturelles). For my 
o-RTi part, I never admitted them, because, in the first place, I never 
could see the intestines which form the communication between the 
stomachs, and likewise because I have observed, many years since, 
that these supposed stomachs were moving in the interior of the 
body of many species with great rapidity, in the same manner as 
the granules which circulate in the joints of the Chara. I have 
often seen Vorticella with nine or ten large globules of indigo in the 
belly, which always moved round a centre, and thus showed, in the 



TNPrsORTAL AlflMAICTTLES. 37 

most evident manner, that they could not have a communicating 
canal between the stomachs, pro\ided with an oral orifice and an 
exti-emity directed to the mouth. 

"But it will be asked, what are these vesicles and balls of the 
same diameter existing in the bodies of the Infusoria, and which 
have been taken for stomachs ? This question I have continued to 
ask myself, till an attentive and long-continued investigation has 
enlightened me as to their origin. 

" The true Infusoria are vesicular beings, whose interior are filled 
■with a mucous substance ; the thickness of the membrane forming 
the vesicle, can easily be ascertained in some of these animals ; and 
in many species I have noticed in this membrane an obvious spiral 
structure, which establishes a complete analogy between it and 
cellular vegetables. In the large Infusoria, a cylindrical canal (the 
oesoj)hagus) obliquely traverses the membrane which forms the 
animal. The lower extremity of this canal dilates, more or less, 
when the animal has taken food, even till it attains the dimensions 
of the balls, which are found in the interior of these same Infusoria. 

" The inner siu'face of this part of the intestinal canal is provided 
with cilia, which turn round, not only the alimentary substances, 
but also foreign bodies, till they have acquu-ed a spherical form. 
During the formation of this ball, the stomach (for it is evident we 
must distinguish this organ by that name) has a free commimication 
with the oesophagus, and by means of the ciliaiy apparatus found at 
the exterior, new alimentary substances are introduced into this 
canal, and pushed as far as the stomach, but I could not satisfy myself 
whether the oesophagus was likcAvise beset with cilia in the part 
Avhich separates the stomach from the buccal orifice. When the ball 
has acquired the size of the stomach, it is expelled by its other 
extremity, and pushed into the cavity of the animal. It then forms 
a new ball, if any solid substances exist in the surrounding liquid. 
This second ball is itself pushed into the interior of the cavity of 
the animal, and drives before it the fu-st ball along with the muco- 
sities between the two ; the successive formation of similar balls, by 
the matter received into the animal, continues in the same manner, 
without interruption. It is the simultaneous existence of many of 
these balls that made M. Ehi'enbei'g believe that these animals were 



38 GENERAL HISTORY OF 

Pohjgastric. If solid substances do not exist in the siiironnding 
liquid, then the balls are less solid, and they appear in the forms 
which they present in the Infusoria plunged in colourless liquids. 
In this case, the balls are composed of a small number of particles, 
and princi])ally of a considerable mucous mass, which ujiites them. 
Sometimes two balls of this kind are so pressed against each other 
by the contractions of the animal, that they at last unite. 

" If you wish to follow the formation of these balls, it is necessary 
to commence these observations at the moment when the Infusoria 
are plunged into the coloured liquid. The deglutition of the 
coloui-ed particles takes place very quickly, often in about half a 
minute, and the coloured balls issue one after another from the 
stomach, and are pushed downwards along the internal wall of the 
cavity of the animal. In the genera Paramecium, Kerona, and Vor- 
ticella, the new ball pushes the preceding before it, along with the 
mucosities between them, in such a manner that the fii'st rises along 
the opposite wall, rotiu-ns to the other extremity of the ca'ST.ty, and is 
jjushed downwards on the other side. The balls thus accumulate in 
succession, till they are expelled, one after the other, by the anus. 
The number of these balls is often so considerable, as to fill the 
whole cavity of the animals, and so close together, that they form a 
large mass, which turns slowly xq^on itself, as among the Vorticelh. 

" This rotation is the result of the force with which the newly- 
formed ball is pushed from the stomach into the cavity, and moves 
along the under side of the preceding ball. In other cases, where 
there are not yet many balls, we likewise remark the cii'cular rota- 
tion alluded to, but I cannot, in this instance, say what is the cause 
of it. 

" Thus, in the true Infusoria, the substances which they absorb 
are introduced into the abdominal caAdty in the form of balls, and 
from these the stomach extracts the nutritive substances. The 
residue remains in these same balls, the mucosities interposed are re- 
absorbed, and even in the anterior of the stomach the particles of 
the baU are disintegrated, although this happens but seldom, 

" What is the nature of those vesicular cavities, of such gi-eat 
numbers, and so variable in size, which appear in the interior of tho 
Infusoria ? They are not stomachs, they possess nothing in conimon 



INrrSOBIAL ANIMALCTTLES. 39 

\rith the balls of which Ave have spoken, although the latter may get 
into them singly, but this can only be considered as accidental. 

" We may trace the formation of these cavities, and perceive their 
sudden and complete disappearance, with as much ease as the forma- 
tion of the balls. Nay, more, it is sometimes possible to see how 
one of these cavities moulds itself over a ball, and speedily after- 
wards disappears. The microscope shows that these cavities are not 
lined with a particular membrane, but are mere excavations of the 
pulpy substance. They likewise often appear very near the inner 
surface of the mem])rane which forms the skin of the animal, and 
some of them increase to such a size that their diameter is equal to 
the thii'd or the half of that of the entire cavity of the Infusoria. 
The slight refraction which the rays of light undergo at their cir- 
cumference, proves that these cavities ai'e not filled with air, but by a 
liquid; and in the large Infusoria, it is easy to satisfy ourselves that 
they do not open on the exterior. Similar cavities are formed in the 
mucus of true cellular plants, pai'ticularly in certain aquatic Cryp- 
togamia. 

" My botanical labours prevent me from carrying these re- 
searches farther, but enough has been said to induce the naturalist 
to pursue them. They require a great degree of perseverance, 
for it is not easy to establish these facts in all Infusoria, but they 
are of high importance, since the order Polygastrica has already 
been admitted into many modern ti'eatises on Zoology." — I]d. Fhil. 
J. vol. xxviii. 

We may add the resume given by M. Dujardin, of the views 
entertained by him, regarding the organization of Infusoria. " The 
Infusoria (leaving out of the question the SystoUdes or Rotatoria, 
which are much more elevated in the scale of animals, and the 
Bacillaria, which, along with the Closteria, are more nearly related 
to the vegetable kingdom) have theii' origin, for the most part, from 
unknown germs, in artificial and natural infusions, stagnant water, 
and rivers, or such portions as rest over vegetable remains — no other 
mode of propagation, except self-division, being well ascertained. 
The fleshy substance of their bodies is dilatable and contractile, like 
the muscular flesh of the superior animals, but present no absolute 
trace of fibres or membrane, appearing, on the contrary, homogenous 



40 GENEEAL HISTOKT OF 

and diaphanous, save in the cases where the surface appears reticu- 
lated fi'om contraction. 

" The fleshy substance of the Infusoria, isolated by tearing, or by 
the death of the animalcule, appears in the li(;[md as lenticular discs 
or globules, which refract light but slightly, and are capable of form- 
ing spontaneously, in their substance, spherical cavities, analagous, 
in appearance, to the vesicles of the interior. 

The vesicles formed in the interior of the Infusoria are destitute 
of a proper membrane, and can contract even to so gi'eat an extent as 
to disappear, or, several may coalesce or unite together. Some are 
produced at the base of a sort of mouth, and are destined to contain 
the water swallowed with the aliments ; they then pursue a certain 
course, in the interior, and conti^act, and leave nothing in the middle 
of the fleshy substance except those particles not digested, or they 
can evacuate their contents externally, by a fortuitous opening, 
which may be reproduced several times, although not as the identical, 
yet towards the same point, and which may load to the belief of the 
presence of an anus. 

" The vesicles containing the aliments are independent, and 
neither communicate with an intestine nor Avith each other, save in 
those cases where two vesicles incorporate together. 

" The other vesicles, which contain nothing but water, are formed 
much nearer the sm-face, and appear to be able to receive and expel 
their contents through the meshes of the tegument. "We may, with 
Spallanzani, consider them as respiratoiy organs, or, at least, as 
intended to multiply the points of contact of the interior substance 
and the surrounding fluids. 

" The external organs of motion are flagelliform filaments, or 
vibratile ciHa, or cirrhi, of more or less size, or fleshy prolongations; 
which, according, as they are more or less consistent, appear formed 
of the same living substance, and are conti'actile themselves, through- 
out the whole of their extent. None are dermoid or comeaceous, 
or secreted by a bulb. Except some contractile integuments, the 
pedicle of Vcrticellae, and the bundles of homy spicula, which invest 
the mouth of certain species; all the li-ving portions of the Infusoria 
decompose almost immediately in water, after the death of the animal. 

*' The eggs of the Infusoria, thcii- generative organs, their organs 



INFUSORIAL ANIMALCULES. 4l 

of sense, their nerves and vessels, cannot be exactly determined, and 
everything inclines one to believe that these animalcules, although 
endowed with a degree of organization, in accordance with their 
mode of life, cannot possess the same systems of organs as do the 
superior animals." 

" The coloured points, for example, commonly red, wlaich have 
been regarded as eyes, cannot, "nith the least certainty, receive that 
appellation." (Ann. des Sciences, 1840.) 

The recent opinions of Siebold are opposed to those arrived at by 
the observations of Ehrenberg. 

Siebold does not regard the vesicles or sacs, as digestive organs ; 
and the existence of an intercommunicating intestine between them, 
is altogether denied. The Astoma (mouthless animalcules) are 
described as noiuished only by a general absorption from the surface. 
In the Stomatoda, with evident mouths, Siebold represents the mouth 
as continued into the interior by a sort of oesophagus, wide, differing 
in length, and straight, ciu'ved, or even spiral, terminating abruptly 
in the general loose parenchyma of the body. When food is sought, 
it is drawn towards the mouth by the action of the siuTounding cilia, 
and having been received into the mouth, enters the cesojihagus, and 
is thence pushed onward by a contraction of the part, in the form of 
a rounded globule, and enters the loose interior parenchyma. The 
food, so introduced, appears mostly like a minute drop of water, it 
may be holding some solid particles in suspension, after a longer or 
shorter sojoui-n in the interior, and a greater or less cii'cuit, it is in 
most Stomatoda ejected thi'ough a distinct and fixed anal outlet, and 
not as Dujardin states, from any portion of the sui'face indifferently. 
The anus is generally situated at the opposite extremity of the body 
to the mouth, and on the luider surface, when this orifice is wanting, 
the nutriment matter is both received and expelled by the mouth, as 
in Polype. (See Microscopic Cabinet, Plate VII.) 

The possession of distinct walls by the vesicles is also not admitted 
by Siebold, since coalescence is sometimes seen to occiu- between 
them. That there is no connecting intestinal tube, is, to the same 
observer, proved by the great mobility of these globules in the 
parenchjona, as well as by the fact, that the nutritious particles, fii'st 
and last swallowed, become mingled confusedly together ; and lastly, 



42 GENERAL HISTORY OF 

by the obsei"vation of an occasional circulation within the animal 
of the vesicles (similar to that of the contents of the cells of Chara, 
&c.), in Vaginicola, Vorticella, and in Loxodes hirsaria. 

This account of the digestive appai'atus, by Siebold, agTees gene- 
rally, "with that given by Professor Boeck, of Sweden, (Oken. Isis for 
1848). Again Focke states (Reports Eay Society, 1845) " that in 
Loxodes, Bursaria, Paramecium aurelia, and in Polygastrica, he saw 
the cavities filled with pigment, intersecting each other in varied 
series, and concluded from this, that the digestive apparatus is not 
separated from the parenchyma, but that the parenchyma of these 
animals, consisting of cells, encloses the fluid nouiishment, received 
from without in narrow spaces, which may be compared with the 
intercellular passages of plants. The same observer also states, that 
on colouiing the fluid containing various proboscidated monads, some 
individuals remained quite colourless, whilst others were saturated 
■s\dth the pigment." 

In none of the families included by Ehrenberg under the general 
denomination of Infusoria, is less indication of a polygastric structure 
to be met "with than in the Closterina and Bacillaria — the Desmidiece 
and Biatomacece, of other authors. It is true that that reno"wned 
micrographer speaks in various places of the detection of stomach 
sacs in several genera of the Bacillaria, but the appearances so 
interpreted, resemble those met "ndth in the vegetable cells of acknow- 
ledged Algae and of other plants, and to which no one has ever 
thought of assigning a digestive function. These globules, or so- 
called sacs, are stated to perform an intercellular rotation in the 
Desmidiece, resembling that of the contents of the cells of Chara, 
Valisneria, 8cc. (See Section on Bacillaria). 

But if Ehrenberg has encountered many opponents to his poly- 
gastric hypothesis, he has had a few come to his support, and among 
the rest, M. Eckhard, once a pupil. The latter speaking of the 
digestive function, observes, "in such forms as are not too minute, 
we can distinctly see how the nutriment, artificially supplied, con- 
stantly takes a definite course in the body ; in some instances, the 
first portion of the alimentary tube can, when not in action, be 
observed, as in Epidylis grandis ; it is then frequently seen to be 
covered on the inner sm-face with cilia, which, in the Oi)ercularia, 



INFUSORIAL ANIMALCULES. 43 

may even be counted. But that this alimentary canal does not, after 
a short course, terminate abruptly in the body, can also be proved in 
the Epistylis grandt's." 

" In this animalcule, a portion of coloiu-ing matter swallowed, is 
seen to course along an intestine, and enter a ceU. I also once atten- 
tively observed, what appeared to be the extremity of the intestinal 
canal, to ascertain what the further coui'se of the coloiu-ed particles 
would be. At this time the animal had not filled any of the cells in 
its inside ; suddenly two lateral cells became filled, although I did 
not perceive any nutriment pass along the common tube. This 
clearly points out that the two cells must be in connexion with the 
common cavity, from which they had become fiUed, and when, after 
the animal has fed for a considerable time, we see that similar filled 
cells are diffused thi'oughout the body, this phenomena affords a 
groimd for the supposition that the intestinal cavity is of greater 
length than we should at first sight imagine." (Wiegmann's 
Ai'cliives, 1846, translated in Annals v. xviii, p. 433). 

Since the above was written, we have met with the opinions of 
Professors "Wagner and Yan der Hoeven, as expressed in their recent 
works: (Wagner's " Zootomie," 1848, Sect. Infusoria; and Van der 
Hoeven's "Lehbuch der Zoologie," 1850). Wagner aflirms that, 
" by an examination, however close, no one can convince himself of 
the actual existence of such an organization as Ehrenberg affiiTns." 
Like Siebold, he describes the derivation or formation of the vacuolse 
(stomach-sacs, SJ7i.) from without, but differs from that observer in 
not regarding their production as a consequence of the primary in- 
troduction of water. 

"With Van der Hoeven, all coincide in denying the existence of an 
enclosing wall to the vesicles, and of an intercommunicating tube 
between them ; and aU assert the ever-varpng number and disposi- 
tion, as well as the movements (even rotatory) of these supposed 
stomachs. In the course of argument, "Wagner says, that " in many 
Infusoria, where larger bodies, such as I^Taviculae or joints of Algae, 
have been swallowed, no surrounding vesicle or sac is \-isible ;" and 
these large bodies will sometimes occupy the entire length or breadth 
of an animalcule. Where no mouth is visible, nutrition is carried on 
by the general siu'face. 



41 GENERAL HISTOEY OF 

From the preceding conflicting opinions and observations, no satis- 
factory deduction can be made ; Ehrenberg's opinions, however, are 
entitled to great respect, although the theory of a polygastric structure 
may not admit of demonstration. 

The annoimcement of Ehrenberg of the discovery of a dental 
apparatus, must find place in this section. This apparatus occui's in 
the foiin of a cylinder of long bristly teeth, placed behind the oval 
aperture, and is readily seen in Ckihdon, Nccssula, Chlamidodon, and 
Prorodon teres. See fig. 283. 

Section XIV. — Of the Vascular and Respiratory Systems, and of 
the Secretions of Polygastrica. — In no creature of this class can a 
vascular system be satisfactorily demonstrated : — that thought to 
have been such in Paramecium aurelia, was merely clusters of ova. 

The above statement follows from the researches of Ehrenberg ; 
but Siebold, "Wiegmami, and others, would trace the first outHne of 
a circulatory apparatus in the existence of the conti'actile vesicle, 
found in all those with evident mouths f StomatodaJ, as well as in a 
few without such orifice (Astoma), as mentioned in the section on 
the reproduction of Polygastrica. Ehrenberg assigned a very different 
purpose to the contractile vesicles, regarding them as spermatic sacs, 
the nucleus being the secreting testis. 

The Berlin natui'alist mainly based this h}-[)othesis on the simi- 
larity of the contractile vesicles to those in Rotatoria, which he 
frilly believed to foi-m a part of the male generative apparatus. But 
since modern researches have overtmiicd the supposition of the 
monoecious natiu^e of Rotiferce, and the exposition, consequently, of 
their generative apparatus, as given by Ehrenberg, all analogies 
resting on the latter, fall to the groimd. Indeed, the argument from 
analogy would now be the other way ; for as such vesicles in the 
Rotatoria have no generative character, it might be assumed that 
their analogies in the Polygastrica, are alike devoid of it. 

The contractile vesicles in question, appear like clear hollow spaces 
in the parenchyma of the Infusoi'ia, the contraction (systole) of 
which, according to Ehi-enberg and his pupil Eckhard, (Wiegmann's 
Arcliives, 1846, and Annals Nat. Hist. vol. xviii. p. 433), may be 
regular or iiTcgular, but is defined by Siebold as rhj-thmical. 

In most genera, but one vesicle exists, in others two, and in a few 



INFUSORIAL ANIMArCULES. 45 

examples, even more ; but, in the latter case, the animalcule is 
usually in the act of self-division. When more than one vesicle is 
present, there seems no necessary correspondence between the systole 
and diastole of each. 

With respect to the number of these sacs, in particular species, 
there is much difference of opinion (only to be reconciled bj- the 
observations of others, and by accurate deiinitions) between Ehrenberg 
with his disciple Eckhard, and Siebold. The last-named wiiter 
affirms that the dctcnuination of these vesicles, by Ehrenberg, is 
altogether arbitrary, one or two being called sperm sacs, and others, 
just like them, stomachs, as, for instance, in Amphileptus Meleagris, 
and in a A. LonglcolUs. Ehrenberg's views are, however, supported 
by Eckhard, who finds some dilFerence in the character of the con- 
tractions in the different sacs, and affirms that he is unable to verify 
the existence of the lateral abdominal contractile vesicles in Stentor in 
the elongated one in Spirostomum mnhiguum, described by Siebold. 
Yerglcichenden Anatomic der Wirbellosen Thiere Vol. I. In Para- 
mecium, the conti-actile vesicle is large, and has from 6 to 8 radiating 
prolongations, which are filled when the central reservoir empties 
itself, and become invisible, when its diastole occurs. 

Erom this, and other like phenomena, presented by these contractile 
vesicles, Siebold, and others, attribute a cardiac nature to them, sup- 
posing that upon their diastole, they become filled with nutritious 
fluid, derived from the parenchyma, thi'ough the insterstices of which 
it is again forced, on the occurrence of the systole, and stagnation, 
thus avoided. 

The hypothesis of their generative ftmction, Siebold declares per- 
fectly gratuitous; that an incessant projection of seminal fluid from these 
vesicles, involves, in itself, a supposition opposed to all analogy ; and 
further, that the purpose of the nucleus as a testes, and even the ex- 
istence of recipient ova in the parenchyma, are more than doubtful. 

A process of respiration, — a renovation of the fluid in the paren- 
chyma, and around the animalcule, is no doubt canied on by the 
external surface, especially by means of the cUia ; and, very probably, 
also by the series of contractile spaces, often seen immediately sub- 
jacent to the integument, as well as by the constantly recurring 
contraction of the supposed cardiac vesicles. The spaces met with 



46 GENEUAL HISTORY OF 

just beneath the surface, are supposed (by Siebold,) to communicate 
with the surrounding liquid. 

That a process similar to that of respiraton is required, is evidenced 
by the necessity of a supply of air to the existence of Infusoria, 
small though that sujDply need be. The more lively animalcules 
require a more complete aeration of the fluid they inhabit, than do 
the plant-like Bacillaria. 

That the faculty of secretion exists, and in an active form, is 
proved by the production of the more or less hardened Lorica ; 
keeping even the Bacillaria out of sight, the hardened cases, as of 
Vaginicola, Cothurnia, Arcella, &c., or the glutinous investment of 
Ophrydina, &c., bespeak its activity. 

Section XY. — Of organs of Sensation in the Polygastrica. — The 
existence of any special organs of sensation in this class is but 
hypothetical, but no doubt can be entertained that the Polygastrica 
have a general sense of contact or of touch. Ehrenberg, however, 
assumes that the coloured specs, seen in many, have a visual function, 
and he consequently gives them the name of eyes, or eye-specks. 
Thus he says, "In forty-eight species, included under the families 
Monadina, Cryi^tomonadina, Vohocina, Astasicea, Binolryina, Peri- 
dinaea, and Kolpodea, eyes are observable, and the colour of the 
pigment is red in aU cases, except one, f OphryoglenaJ in which it ia 
almost black. In connection with the visual organs of Amhlyophis 
and Euglena, nervous ganglia have been seen, which constitute the 
only traces of the evidence of a nervous system." 

The subjects of this section are thus referred to by M. Dujardin. 
" The sense of sight would partake more of the character of reality, 
if the colour of a speck without appreciable organization, without a 
constant form or a precise contour, sufficed to prove the existence of 
an eye. But, for instance, in the Euglena, which are particularly 
cited as characterized by such an organ, the red spot so regarded is 
excessively variable, sometimes multiple, at other times made up of 
irregularly aggregated granules." ^ 

"Analogy, too, is inadequate to the solution of the question ; for, 
on descending the animal scries, to detennine the nature of the 
coloured speck, we have to leap from the Daphnioe (members of the 
Entomostraca,) with a moveable eye, repeating in its composition 



llfFrSCBTAI. ANIMAI.CXTLES. 47 

that of Insects and Crustaceans, to animals presenting nothing but 
difPiised coloured specks. 

" Such spots, whether in number or position, have so little 
physiological importance in the Planaria?, and in certain Annelides, 
that they are often not even to be employed as an absolute specific 
character. In the Rotatoria, the analogy with which is more 
especially insisted on, these pigment spots are, in some species, 
known to disappear from age, and in others to become more evident, 
in proportion to size or development of individuals : so that the 
learned micrographer of Berlin, in his attempt to base the generic 
characters of these animals on the presence and number of the eyes, 
has been led to place in different genera, species very closely allied, 
if not identical. Indeed, that a black or red colour is in general an 
attribute of the pigment of eyes, cannot be a reason for concluding 
an eye to exist wherever there is a red colour ; if so, indeed, we 
must accord them to some intestinal worms, such as the Scolex 
polymorphus, which has two red spots on the neck ; to the actiniae, 
which are often strewed with such specks , and also to some bivalved 
mollusks." 

"If the ability of the Infusoria to direct their course through the 
liquid, and to pui'sue their prey, be appealed to ia evidence, it is 
certainly, in the fii'st place, necessary to verify the reality of this 
faculty, which I think equally fabulous with all related concerning 
the iustiucts of these animals. Indeed, it would not even prove the 
red specks to be eyes, since the greatest number of Infusoria 
supposed to be endowed with such a faculty, are in want of them ; 
and those which do possess them, do not exhibit that power ia a 
higher degree of development." 

M. Ehi'enberg, following up his line of reasoning, after having 
assumed the signification of the red points, has recourse to thi» 
assumption, to demonstrate the ti'ue nature of certain white sj)ecks, 
more or less distinct, which he supposes to represent nervous- 
ganglions, — " These specks are the only parts of a nervous system 
spoken of as seen, the rest is altogether furnished by analogy." 

Siebold, "Wagner, and others, concur with M. Dujardin in denying 
the visual character of the coloui-ed spots of Infusoria, as weU as the 
presence of nerve matter in an isolated form. 



43 GENERAL HISTORY OP 

Siebold remarks, that Ehrenberg insists much on the red colour as 
a distinctive indication of a visual organ, but erroneously so, since 
other colours prevail in the unquestionable eyes of Insects and 
Crustacea, such as blue, and sometimes violet or green. 

Moreover, the admission that Infusoria possessing eye-specks have 
a general sensation of Hght, does not prove the optical nature of 
those specks, because forms, destitute of them, exhibit a like sensi- 
bility of the presence of light, and fiu'ther, as Siebold observes, if 
sight be limited to the simple discrimination of light from darkness, 
this faculty might be secured, without any optical apparatus, by the 
entii'e sensitive surface of the body. 

According to Morren, the red pigment spots of Lagenella, Crypto- 
glena, and Trachehmonas, cannot be eyes, as in the last, the colouring 
matter may be distributed over the whole body, when the animal, 
on this supposition, would be changed, in toto, into an eye. 

The very recent and extended researches of M. Thuret (Sur les 
Zoospores, in " Annales des Sciences jSTaturelles," vol. xiv. Z^^ series, 
1850,) on the reprodxictive gems, or Zoospores of Algae, prove these 
bodies to possess red eye-like specks, resembling to those seen in the 
Polygastrica, but which disappear when the Zoospores attach them- 
selves, and germination proceeds. These bodies, moreover, direct 
themselves, in general, towards the light, and thus exhibit the same 
fonn of sensation of its presence, as do the Polygastrica themselves. 

The general sense of contact possessed by the bodies of the 
Polygastrica, would oftentimes seem to exist in a higher degree in 
their cilia, proboscides, and other processes, just as in the tentacula 
or feelers of insects ; and so far such processes are special organs of 
sensation. But even the cilia, and the proboscides of the flagelliform 
variety, are not peculiar to the animal Polygastrica, for they are also 
found as processes of Zoospores in many Algae. 

Section- XVI. — Pcproduction of Polygastrica. — Monas vivipara is, 
according to Ehrenberg, the only species of this class that is 
viviparous, though some moAdng granules observed amongst the 
Bacillaria, have been supposed by him to extend this condition. 
"With this exception, they may be termed o^iparoixs, though besides 
the formation of eggs, which is a very fertile mode of increase, they 
also propogate, by means of a self-di^■ision of the body of the 



INFUSORTAT, ANTMALPULEg. 49 

Rnimalciile, into two or more individuals ; also, by tlio growth of 
gemmules, or buds, upon the parent. These various modes of propa- 
gation account for their almost incomprehensible increase of number 
in a very short space of time, and which has often astonished 
observers. 

In the genus Chsterimn, the curious formation of double gems has 
been observed by Ehrenberg, and is figured in plate 1. fig- 67. That 
obser^^er remarks, " The increase by spontaneous di\ision, is the 
character which separates animals from plants. It is true that the 
gemmation in plants, especially, in very simple cells, is at times very 
similar to the di^vision in animals ; but this relates to the form, not 
the formation. A vegetable cell, apparently capable of self-division, 
produces one, or contemporaneously many exterior buds f gemma- J, 
without any change in its interior. An animal which is capable of 
diAT-sion, first doubles the inner organs, and subsequently decreases 
exteriorly in size. Self-diA-ision proceeds from the interior towards 
the exterior, firom the centre to the periphery; gemmation, which 
also occurs in animals, proceeds from the exterior towards the 
interior, and forms first a wart, which then gradually becomes 
organized." — {Annals Nat. Hist. v. ii.) 

The importance of this power, so forcibly exhibited in the various 
tribes of animalcules, is well shcAvn by the fact, that a creature, 
iuA^sible to the naked eye, can, in the space of four days, give origin 
to no less than 140 billions of beings; and as, fr-om the size, &c., of 
the bodies, we can easily calculate that 40,000 millions of individuals 
exist in a cubic inch of the polishing slate of Bilin, so 70 billions 
must be necessary to form a cubic foot of the same staaicture. 

This difference in nature between self-division in vegetable cells, 
and in the cell-like bodies of Pohjgastrica, above insisted upon by 
Ehrenberg, is opi^osed to the result of some recent researches. Thus 
Mohl and Henfrey state, that when a plant cell is about to undergo 
fission, the inner mucilaginous layer of its wall — the primordial xdride 
manifests a constriction in the future line of separation, which 
presently evidences itself in the outer cell- wall, and progresses until 
the di^dsion is complete. (See observations on self-division in the 
Bacillaria, imder the sections Desmidiacea and Diatomacea in part III. 

In the Vorticellina, M. Dujardin recognizes the existence of repro- 

E 



50 GENERAL HI3T0BV OF 

duction by gemmation ; but regards the vi\'iparity of Ilonas vivipara 
as extremely doubtful, and tlio formation of ova in any Infusoria 
and their disposition, as far from established. He would, moreover, 
look upon the appearances observed and considered by Ehrenberg as 
indicative of opposition, merely as instances of the phenomenon of 
diffluence, or of the breaking up of the gelatinous substance {corcode) 
of the animal into spherical atoms, from want of moisture. 

Siebold agrees with Dujardin, in thus limiting the process of repro- 
duction to the two forms of gemmation and of spontaneous fission, 
and from this hypothesis of the non-production of oA^a by Inftisoria, 
argues the absence of true generative organs. The appearances 
interpreted by Ehrenberg as evidences of the presence of ovaries, 
testes, and vesiculoe seminales, afford, according to Siebold, no ground 
for the assumption of such functions. 

The body, presumed by Ehrenberg to be the testis of Polygastrica, 
is generally found occupying nearly the centre of the animalcule, 
and is readily distinguished from the surrounding loose parenchj-ma, 
by its more solid granular character, its clear outline, and generally 
by its dull yellowish coloiir. 

Although the office of this body in secreting a spermatic fluid may 
be justly called in question, direct observation being contrary to it, 
yet this so-called testis, or, perhaps, more correcth^, this nucleus, 
certainly plays a most important part in the well-observed mode of 
propagation by spontiineous fission; for whenever fission, whether 
longitudinal or transverse, is about to occur in an animalcule, the 
first change observed is a progressive constriction of the nucleus, 
succeeded by that of the body generally. This constriction goes on 
till division is complete, each segment of the body being consequently 
provided with a nucleus. The di-vision of the nucleus, as an essential 
element iu the process of spontaneous fission, may be well observed 
in the transverse division of Parameeium, Bursaria, or Chihdon. 

Sometimes, two, or even more nuclei, are met with in animalcules, 
as in AmpTiUeptus anser and A. fasciola (figure 314), in StylonycMa 
Mytilus, in Stentor coeruletfs, &c. 

The nucleus, from the circumstance of being the last part to suffer 
death, remaining unchanged when the destruction of the surrounding 
parenchyma is rapidly advanciiig, may be supposed to partake of a 
higher dcgi'ce of vitality. 



INFUSORIAL ANIMALCULES. 51 

Professor Owen, in his recent learned and able Essay on Par- 
thenogenesis, refers to the initiative, assumed by the nucleus of 
Infusoria, in their reproduction by spontaneous fission, between 
which and the essential contact of the spermatozoon with the germ 
cell, as a preliminary to the primary process of self-diWsion of the 
latter, in the course of the development of more perfect animals, he 
indicates an analogy ; and, after ha^ong completed the comparison of 
the results in the two cases, goes on to say, " this is certain, that 
the analogy between these phenomena in the multiplication of the 
parts of the germ-mass, and those of the nucleus in the multiplication 
of monads, is so close, that one cannot reasonably suppose that the 
nature and properties of the nucleus of the impregnated germ-cell, 
and that of the monad can be different. 

" Therefore, I infer, that the nucleus of the Polygastric animalcules 
is the seat of the spermatic force ; it can only be called testes, figur- 
atively, it is the essence of the testis. It is the force which governs 
the act of propagation by spontaneous fission : and, if Ehrenberg be 
correct, in viewing the interstitial coipuscles as germ-cells (to which 
opinion Professor Owen inclines), these essential parts of ova may 
receive the essential matter of the sperm from the nucleus, which is 
discharged along with them in the breaking up of the monad, which 
Ehrenberg regards as equivalent to an act of oviposition ; and im- 
pregnated germ-ceUs may thus be prepared to difiiise through space, 
and carry the species of Polygastric animalcules to a distance from 
the scene of life of the parent." (p. 67, Ed. 1849.) 

Professor AVeisse, of St. Petersburg}!, has detailed some observations 
(In the " Transactions of the Petersbui-gh Academy," and in 
Wiegmann's "Archives fiir Faturgeschichte" for 1846,) on the 
Chlorogonium eucMorum, which he considers decisive of the occur- 
rence of reproduction by ova, and, also, as demonstrative of some 
genera of Ehrenberg, being but different stages of development of 
the same being. Thus, he describes the contained green matter of 
the Chlorogonium to develope, by spontaneous fission of itself, nu- 
merous young animalcules, at their first escape, resembling ZfvelJa 
Bodo, and in further stages, Chlorogonium euchlorum and Glenomorunt 
ting ens. The young beings escape by a transverse rupture of the 
parent, wliich, by this form of oviposition, is itself sacrificed, dis- 
appearing as a shrivelled broken sac. 

E 2 



52 



GENERAL HISTOBY OF 



But the doubt may arise, whether the being Weisse observed "vras 
the true animal CMorogonmn, or only a thecaspore or zoospore of 
an Algae (see Thuret's Essay, before quoted), a production so similar 
to the green-coloured Infusoria, that we have really no means of 
distinguishing bet^yeen tlie two, and, what is more, a production 
which is known to develop e by the fission of its endochrome or gi-een 
contents. 

Not only did Ehrenberg discover a testis in the nucleus of Poly- 
gmtrica, but conjectured the pulsating sacs and their prolongations, 
existing in all those with a mouth, and in some others, to represent 
a spennatic sac with vas-deferens and vesiculoe seminales. But the 
majority of obser\-ers would rather consider them as the fii'st 
rudiments of a circulatory system ; and we shall defer any further 
mention of them till that system is considered in a following section. 

Before dismissing the subject of the propagation of Infusoria, it is 
right to notice some recent researches of M. Pineau (Annales des 
Sciences NatureUes, vol. III. 3rd series, 1845, and vol. IX., 1848), 
in which he endeavours to prove the transformation of organic 
matter into definite organic beings, and that there is a perfect 
analogy between the production of cells in general, and that of 
animalcules, and of microscopic infiisory plants. Moreover, he would 
extend the phenomenon of transformation to the organised beings 
when developed. 

Thus he states, that in an infusion of different plants, the first 
index of the progress of organization was a granular mass, sub- 
dividing into granular globules. Of these, some of the more 
advanced presented diverging, but motionless processes; in others 
more isolated, those appendages exhibited an oscillatory movement, 
and in them he identified a species of Actinophrys. At first, the 
radiating expansions were all alike, but in the progress of develop- 
ment, one was observed to affix itself to a neighbouring body, and to 
outgi'ow the rest. In this form he recognized the Actinophrys 
pedicellata (Dujardin). 

He next describes the appearance of a pjTifonn animalcule seated 
on a non-contractile stalk, with the trace of a circular orifice, which 
he believed might be assigned to the genus Amieta, whilst the 
succeeding phase of evolution exhibited perfect Vorticella. 



IKFtrSOKIAL ANIMALCULES. 53 

M. Pineau, in a second communication in 1848, gave the further 
course of development, affii-ming that, at a certain period of their 
existence, the Vorticclla undergo metamoiiihoses analagous to those 
of insects ; that after having passed through a chiysalis-Hke state, 
they give birth to an animalcule completely different from their 
primitive form. (See family Vorticellina, Part III.) 

Without detailing all the changes recorded by Pineau, it may 
suffice to state, he saw the Vorticellce lose then- pedicles, assume the 
form of an egg-shaped globule, and eventually, he believes, become 
converted into Oxytrichce. 

Doubting much, M. Pineau's hypothesis of the transformation of 
formless organic particles into definite organic beings, we wovdd, 
however, receive his statements concerning the metamorphoses of 
animalcules with more readiness, inasmuch as many observers have 
been led to believe in the reality of such ti-ansactions ; and we may 
caU to mind that, according to Professor Baer, and his followers, 
Lcuckhart and Rcichenbach, the Infusoria, as a class, have no 
existence, but are merely embryonic forms of higher animals. 

That skilful English observer, Mr. BrightweU, of Norwich, also 
believes that he has detected a cycle of changes in the Zoothamnium 
arhuscuU, illustrative of Steenstrup's hypothesis of " alternation of 
generations;" or of that of a 'spermatic force,' according to the 
more philosophic inteipretation of such phenomena by Professor 
Owen. (See Zoothamnium, Part III.) 

Most of the preceding account, of the reproduction of Infusoria, 
applies especially to those of an undoubtedly animal nature, and 
but partially to the doubtful organisms of Ehrenberg's families 
Closterina and Bacillaria. The latter, besides propagating in common 
with true animalcules by spontaneous fission, also do so by what is 
called conjugation, a process peculiar to themselves. However, we 
shall defer gi'S'ing an account of this interesting phenomenon, until 
we especially consider the characters of those families exhibiting it. 

"We can now state that Wagner, " Zootomie" sect. Infusoria, 1848, 
and Van der Hoeven, " Handbuch der Zoologie, 1850," agree with 
Siebold and Dujardin in restricting the reproduction of Pohjgastrica 
to fission and gemmation, that by ova being denied. All those named, 
coincide, likewise, in opposing Ehrenberg's views of the contractile 



54 GENERAL HISTORY OF 

vesicles and nucleus (testis), and would assign to the former, a cardiac 
or circulatory function. 

S])ontancous Generation. — The Infusoria were, veiy generally, con- 
sidered to have a yeneratio primitiva, or, in other words, to be 
produced by some fortuitous combination of circumstances from in- 
organic matter. That such a statement is untenable, most persona 
will be inclined to admit, who have perused the descriptions con- 
tained in the Third Part of this work. All the obsen'ations that can 
be depended upon, tend to show that infusions of vegetable or 
animal matters, whether natiu-al or artificial, only offer food for the 
nourishment of these living atoms, whose germs are almost eveiy- 
where present, but are only developed in situations congenial to 
their natm-es. It is now well ascertained that the old notions of 
certain vegetable infusions producing a definite species of Infusoria, 
is an eiTor ; that, in general, we have, in all artificial infusions, only 
common species, and that these invariably making theii' appearance, 
we may fairly presume their eggs are more generally dispersed, and 
more readily developed. On the other hand, the llotatoria, and 
more beautiful species of Polygmtrica, ai'e confined to localities more 
open to the fi'esh air. Ehi'enberg, for man)' years, has experimented 
with simple spring water, with distilled water, and rain water, and 
these, both boiled and cold, as also with and without vegetable 
matter ; that in open vessels, after a longer or shorter time, depend- 
ing upon temperatui-e and other cii'cumstances, he invariably found 
tlie Infusoria ; while, in closed vessels, they were rarely to be met 
with ; so that it seems, we may consider getieratio aquivoea, even in 
Infusoria, as an unphilosophical hypothesis ; and that the same fixed 
laws of Creative Wisdom, which regulate and govern the smallest 
satellite and the largest stany world through boundless space, has 
established the same law for the development of a living atom, as is 
manifested to us in the largest animal that inhabits this planet. 

On this subject we may refer the reader to the often quoted ex- 
periment of M. Schultz, ■\\'ho contrived an apparatus to prevent the 
introduction of any living germs, by the atmosphere, in a portion of 
water experimented on. This experiment has generally been viewed 
as decisive against the doctrine of spontaneous generation. It is 
thus recorded: — "1 filled, (says Schultz) a glass flask, half full of 



INFTJSORIAL ANIMALCULES. 55 

distilled Avatev, in which I mixed various auinial and vegetable sub- 
stances : I then closed it with a good cork, tlii'ough which I passed 
two glass tubes, bent at right angles ; the whole being air tight. It 
was next placed in a sand bath, and heated until the water boiled 
violentlj', and thus all parts had i-cachcd a temperature of 212°. 
^Vliile the watery vapour was escaping by the glass tubes, I fastened 
at each end an apparatus, which chemists employ for collecting car- 
bonic acid ; that to the left was filled with concentrated sulphuric 
acid, and the other with a solution of potash. By means of the 
boiling heat, everything living, and all germs in the flask, or in the 
tubes, were desti'oyed, and all access was cut off by the sulphmic 
acid on the one side, and by the potash on the other. I placed this 
apparatus before my window, where it was exposed to the action of 
light, and also, as I perfoi-med my experiments during the summer, 
to that of heat. At the same time I placed near it an open vessel 
with the same substances that had been introduced into the flask, 
and also after ha'^dng subjected them to a boiling temperatiu'C. In 
order now to renew constantly the air within the flask, I sucked 
with my mouth, several times a day, the open end of the apparatus, 
filled with solution of potash ; b}' which process the air entered my 
mouth from the flask through the caustic liquid, and the atmospheric 
ah' from without, entered the flask through the sulphuric acid. The 
air was of course not at all altered in its composition by passing 
through the sulphuric acid, but if sufiicicnt time was allowed for 
the passage, all the portions of living matter, or of matter capable of 
becoming animated, were taken up by the sulphuric acid and 
destroyed. From the 28th of May, till the beginning of August, I 
continued, uninterruptedly, the renewal of the air in the flask, 
without being able, by the aid of the microscope, to perceive any 
li^-ing animal or vegetable substance, although, during the whole of 
the time, I made my observations on the edge of the liquid; and 
when, at last, I separated the different parts of the apparatus, I 
could not find in the whole liquid, the slightest trace of Infusoria, of 
conferva, or of mould. But all the three presented themselves in 
great abundance, a few days after I had left the flask standing open. 
The vessel which I placed near the apparatus, contained, the follow- 
ing day, Vibriones and Monads, to which were soon added larger 



56 



GENERAL HISTOEY OF 



Polj'-gastric Infusoria, and afterwards JRotataria." (Ed. Phil. Jour. 
V. 23.) 

Sectiox XVII. — Of the affiyiities and classification of Polygastrie 
Animalcules. — Our next business is to detenninc the affinities existing 
between the Pohjgastrica and other animals and plants. 

Commencing- with the simplest ; life is seen so obscurely manifested, 
that in many cases, we know not -SA'hether to esteem it vegetable or 
animal, and the organisms of both kingdoms, in theii- earliest phase, 
are, to common observation, identical. In such, there is no other 
indiAddualization of organs than is necessaiy to form a centre of 
generative or spermatic force — i. e. a nucleus, in which an energy, 
originating, each half of the dividing nucleus becomes a centre of 
assimilative force, and complete fission of the entire being is brought 
about. Examples in Monodina, and in the vegetable Palmellea. 

The next stage in advance, shows so much of the special modifi- 
cation of the general mass, as is necessary to the pi'oduction of cilia, 
or of one or more filiform processes or proboscides. Many of the 
monads aflbrd examples of this degree of development, which is yet 
so rudimentary and ill defined, that there are no certain means of 
distinguishing -n'hat arc specific, distinct animal existences, and what 
but germs of plants, or the early stages of existence of other animals, 
or of plants. Here again, therefore, aifinities are so close, as scarcely, 
or not at all, to be separated from identities. 

This ciliated monadiform existence belongs to the spores of many 
plants, and to embryonic conditions of most invertebrata, and, for 
convenience, is spoken of by Professor Owen, (Op. cit.) as the 
" Leueophiycan tj-jie." This type is witnessed in the developing 
ova of the sponges, and of the Annelida; and there are sufficient 
grounds for supposing its occurrence, in an early stage of existence, 
of many of the more highly organized Infusoria. 

However, there is one caution to be borne in mind, in seeking for 
the analogy between specific forms and embryonic phases, viz., not 
to cjnfound general resemblance with specific idcntit3^ If it be not 
discernible, we must assume (from what we know of the course of 
development of higher animals) that there is something wanting in 
th(! image, to render it an exact counterpart of the original. 

Uut we have to deal, not only with single monads, but with such 



INFUSOKIAL ANIMALCULES. 67 

beings congi-egated in masses, when a general analogy" may be traced 
between them and the polypes, grouped together, in the structure of 
the sponges. Associated groups of monads are met with in the 
family Volvocina, where each individual contributes to the growth of 
the whole mass, as in the sponge. 

Since writing the above, we have met with the excellent essay of 
M. Thuret, (Op. cit.) in which he discusses the aflfinity of the Zoos- 
pores of Algae with Infusoria (Pohjgadrica.) He whites : " Their 
organization presents great analogy with that of Infusoria. The 
disposition of the cilia is the same in Pheosplwrce (a division of the 
Algae) as in Ccrcomonas and At/qjliimonas, of Dujardin. But it is 
between the reproductive bodies of Conferva3, and certain Infuso- 
ria, coloured green, that the greatest resemblance subsists. I allude 
to the Diselmis viridis, (Duj.,) the Chlamidomonas puhisculus, of 
Elu-enberg. In the form of the body, in that of the flabcUi- 
foiTU cilia, and in the disposition of those cilia, as also in the contents 
of the body, the resemblance is complete. The movements of 
Diselmis are like those of Zoospores, and, like them, they tend to the 
light. In one distinct species, or rather, in a particular state of the 
same species, a very clear red spot is discernible, and a central globule, 
very Hke, in appearance, to the amylaceous graniiles, so fi'equcnt iu 
the cells of green Algoe. These Infusoria appear to act on the 
atmospheric air, like Algae, and the green parts of other plants, dis- 
engaging a gas (oxygen?) imder the influence of light. They ex- 
hale an evident spermatic odour. Their reproduction occiu's by 
spontaneous division; 2-43'oung ones being formed within the common 
integument. I have observed the same mode of reproduction in the 
Eiiglence, which act on the air, and turn to the light, like Diselmis, 
but have an extremely contractile body, changing its figure every 
moment, which will not admit their being confounded with Zoospores, 
and leaves no doubt of their animality. This binary or quaternary 
division is met with also in the various species of Tetraspora, which, 
though ranged with the Algae, appear to me of very doubtful 
vegetable nature. In Tetrasjjora gelatinosa, I have recognised green 
globules, disposed in fours, and each furnished with two cilia of 
extreme length, wliich are lost in the gelatinous mucus, of which 
the frond of this supposed plant is constituted. AU these produc- 



58 GENERAL HISTORY OF 

tions, as A\'ell as Gon'mm, Pandorina, T'olvox, Frotococcus nivalis, &c., 
j)reseut, in U13- oi)imon, characters of animality, too decided, and too 
permanent for it to bo possible to refer tliem to tlie vegetable king- 
dom ; and I think it Avonld prove more convenient to unite them, 
with all the other Infusoria, fPolygastricaJ coloured green, in one 
and the same group, which might be called Chlorozoidefe,''^ (Sec. IV.) 
We have before (Sec. XII.) introduced the sweeping statement of 
!M. Agassiz, and his opinion, that all the mouthless Infusoria are 
nothing but various forms, and phases of development of Alga?. To 
avoid repetition, we will also now refer to the same section for that 
naturalist's views of the affinities of the other groups of Pohjgastrica. 

M. Braun would refer the Vohocina, (see remarks on that family, 
Part III.) to the vegetable kingdom, believing them to be of the 
same tj^e with certain Zoospores, which become composite by 
fissiparous multiplication ; whilst Dr. Burnett, of New York, would 
associate the Vihrionia (see that familj^) with such Algse as the 
T'orula. 

Before proceeding with the affinities of the various Infusoria pos- 
sessing mouths, we may seek those of the peculiar beings included in 
Ehrenberg's families Amahcea and Arcellina, and known to many 
naturalists as Pseudopoda and Rhizopoda. Their muco-gelatinous 
substance is either naked or defended by a lorica. The fonner bear 
the nearest resemblance to minute sponges, but differ, in representing 
but a single individual, and not a complex aggregation, as do the 
latter. However, these singular simple numerous masses, when 
enclosed by a lorica, assume an affinity to a set of beings, often of 
very elaborate external organization, known as PoJythalamia or 
Foraminifera. This affinity is so close, that writers are not yet agreed 
as to which class the Infusoria, or the Foraminifera, several genera, 
ou<'ht to be referred. Thus, Trinema, Fuglyjyha, Rotalia, Vorticialis, 
Cristellaria, kc, genera of Ehizopodes, according to M. Dujardin, 
are included by M. D'Orbigny, among his Foraminifera. This 
diversity of opinion must last until the essential characteristics, and 
peculiar structure of Foraminifera are better kno-WTi. Ehi-enberg 
designates them Polythalamia, and would employ, as a distinction 
between them and his families, Arcellina, Difflugia, &c., the fact of 
the calcareous composition of their shells, stating those of the latter 



INFXTS0R1A.L ANIMALCULES. 59 

to be siliceous, uot calcareous, — but tliis dili'erence, it would seem, 
is questionable. 

Mr. Carter, of Boinl)ay, in an able paper on the fresbwater 
sponges, (Transactions of the Medical and Physical Society of 
Bombay, 1847, Appendix.) points out the close resemblance between 
the separated indi^n duals, or Proteans, to the members of the genus 
Amoeba of Ehrenberg, and concludes \\'ith the remark : — " Thus 
does every step toAvards the ultimate stnictm-e of the freshwater 
sponge, every form that is taken bj- the living matter of which it is 
composed, appear still more nearly to approximate it to the nature 
of the genera of Ehrenberg's Pseudopoda.''' 

The next group in advance is characterized by its members ha-ving 
mouths, and which are known to Siebold as Stomatoda. The affini- 
ties of these animals vary in the case of different families. For 
although the Polygastrica, by their general peculiarities, are separable 
from all other classes of animals, yet their several families have — 
setting aside their disputed polygastric stinicture, hardly any features 
in common, save their smallness, their habitat, and theii' simple 
organization, with, what is important, their propagation by spon- 
taneous fission, and, in almost every case, their want of sjTnmetry. 
Their general conformation, as seen by the plates, is most varied, as 
also is their manifestation of life. Some, as the Vorticellina, are 
fixed by a stem to a foreign object, and in many points resemble 
Polypes, with which indeed they have been classed ; and their 
resemblance is the greater, where the stem is branched and rigid, to 
Sertularian Polypes. 

In its mode of progression, the Colejjs recalls that of the Daphmce, 
but all similarity of organization is wanting. The Euplotes monostylm 
presents several characters belonging to the Rotatoria, but is asym- 
metrical, has no such alimentary canal as the latter, and propagates 
by fission. 

Some anomalous forms, such as Bicti/ocTia, although, by reason of 
their siliceous composition, and peculiar conformation, reckoned among 
the Polyga.striea by Ehrenberg, would appear to approximate nearer 
to the Phytolitharia than to any other class. The siliceous shelled 
Polygastrica have an affinity also with a class of animals newly dis- 
covered and brought together by the indefatigable Prof. Ehrenberg, 



60 GENERAL HISTOBY OF 

wliicli he has named Polycystinea. Several genera of an anomalous 
form, which he at first classed "ndth Bacillaria, he has since united 
M'ith others subsequently discovered under the above-named appella- 
tion. As, however, the internal organization of the Pohjcystine^ is 
unknown, Elu-cnbcrg contents himself by pointing out their agree- 
ment with Pohjgastrica in their siliceous coating (ha-ving chiefly in 
view the doubtful Bacillaria) and microscopic magnitude, whilst he 
indicates, as a distinctive character, the existence of transverse arti- 
culations in the Polycystinem. 

It would be but an exercise of the imagination to seek after 
resemblances between the majority of the Infusoria and higher 
animals, the resemblance could be but fenciful, existing only in 
external form. In studj-ing the Infusoria, the mind should be un- 
biassed by a knowledge of the organization of higher animals ; we 
ought not to set out with the assumption that such living atoms must 
be furnished with the organs of superior existences, and then indulge 
the imagination, by accommodating appearances, observed to our pre- 
conceived notions ; but we should rather endeavour to learn under 
what simple conditions and contrivances, animal life can be manifested 
and continued. 

The so-called class of Polygastrica must still be looked upon as an 
heterogeneous collection of organic beings, which requires the careful 
and persevering industry of observers to exclude aU forms not truly 
animal, as well as those not having a specific identity, i. e., which 
are but transitional embryonic forms. Numerous have been the bodies 
removed from the lists of Infusoria of the older microscopists, by the 
advance of microscopic knowledge, and by the improvement of the 
microscope ; and we may yet look for equally great modifications of 
the existing systems, from the genius and ai'dour of modern research, 
especially on the subject of embryology. 

Since few doubt the expediency of separatiag the Closterina, and 
many advocate that of removing the Bacillaria fi'om the animal 
Infusoria, we shall defer considering the affinities of those families 
(which lean rather to the vegetable than to the animal kingdom) to 
the section especially devoted to them. 

As some remarks occm-red, in the fii-st edition of this work, relative 
to the nature of spermatozoa, it may be right to state that the 



iNFTTsoniAt, antmat,otjt,t;s. C>1 

recent extended and careful inquiries of "Wagner, Leuckhart, and 
Kolliker, (Cyclopaedia Anatomy Art. " Semen"), have satisfactorily 
proved to those wi'iters the non-aiiimalcular character of those 
organic particles. They have explained their peculiar development, 
and the essential part they play in the propagation of animals, aa 
low in the scale as the Rotatoria. 

The discovery of the peculiar spiral and moveable fibres in the 
antheridia of mosses, by Unger, and called spermatozoa, having 
kindled much interest, induced me to introduce a description and 
drawing of them in the first edition (which is retained in the present) 
under the genus Spirillum. The experiments and observations of 
Fritsche and others, have exploded the idea (in the opinion of 
naturalists generally) of those bodies being spermatozoa, or of their 
possessing an animal nature. 

In accordance with Ehrenberg's views of the digestive system, he 
divides the Polygastrica into P. anentera and P. enterodela ; the 
former destitute of an intestine comiecting the several stomach sacs, 
each of which opens dii'cctly into the mouth ; the latter possessing 
one, which, from the various ways it is arranged, gives rise to a 
further division into cycloccBla, orthocwla, and campylocoela. In the 
first of these, the intestine is so ciu:ved upon itself, that its two 
extremities unite at the oral opening — ex. in Yorticellina, and in 
Ophiydina ; in the second, it passes straight through the axis of the 
body — ex. in Enchelia and Colepina ; in the third, it is more or less 
contorted— ex. in Leucophiys, Trachelina, &c. 

But the consideration of the relative position of the oral and anal 
openings, led Ehrenberg to devise yet another arrangement of the 
Polygastrica, calling those forms anopisthia, where, as in Cycloccda, 
the two apertures are united at the fore extremity ; enantiotreta, in 
which, whether in orthocoela or campylocoela, the apertui-es are at 
opposite ends of the animal ; allotreta, where one is terminal, the 
other lateral ; and, lastly, catotrcta, where the two orifices are 
lateral. 

As for the anentera, he divided them into three sections ; the first, 
comprising those without feet or appendages, Gymnica ; the second, 
with variable appendages or processes, Pseudopoda; and the thii'd, 
with cilia, Epitricha. (see Tables, Part III.) 



62 GKNET?AL HISTORY OF 

Professor Siebold not only rojocts the class Polygastrica, but uses 
the temi Infusoria in a veiy limited signification, intending by it 
only those animalcules moved by cilia. To express the beings 
known by Ehrcaiberg as Pohjgastrica, except the Bacillaria and 
Closterina, he has devised the word Protozoa; and he thus arranges 
them : — 
I. Class. — Ixfttsoeia, Animals moving by cilia. 

Order I. — Astoma, Infusoria without a mouth. 

Family 1. — AstasioBa — Genera, Amhlyophis, Euglena, 

Chlorogonium. 
Family 2. — Peridinoea — Genera, Peridinium, Glenodinium. 
Family 3. — Opalincea — Genus Opalina. 
Order II. — Stomatoda, Infusoria with a mouth. 
Family 1 . — Vorticellina — Genera, Stentor, Trichodina, 

Vorticella, Epistylis, Carchesium. 
Family 2. — Ophrj'dina — Genera, VaginicoJa, Cothurnia. 
Family 3. — Enchelia — Genera, Actinophrys, Leucophrys, 

Prorodon. 
Family 4. — Trachelina — Genera, Glaucoma, Spirostomnm, 
Trachelius, Loxodes, Chilodon, Phialina, 
Bursaria, Kassida. 
Family 5. — Kolpodea — Genera, Kolpoda, Paramecium^ 

AmphiJeptus. 
Family 6. — Oxytrichina — Genera, Oxytricha, Stylonychia. 
Family 7. — Euplota — Genera, Euplotes, Mimantophorus, 
Chlamidodon. 
II. Class. — Rhizopoda, Animals mo^^ng by variable processes. 
Order I. — Jlonosomatia. 
Family 1 . — Amcebcea — Genus A7noeha. 
Family 2. — Arcellina — Genera, Arcella, Difflugia, Gromia, 
Miliola, Euglypha, Trinema. 
Order II. — Polysomatia — Genera, Vorticialis, Geoponus, 
Nonionina. 
REcnoN XYIII. — Geographical Distribution of Polygastrica, their 
relative ahundance, ^c. — The Polygastrica, as understood by Ehrcnberg, 
are the most widely diffused of all organized beings. From the icy 
region of Spitzbcrgen, near the North Pole, to the utmost limit 



INFI'SORIAL ANIMALCULES. 63 

attained at the South Pole, in the enth-e cireumferenee of the globe, 
are these organisms found. 

Their distribution in space is co-extensive with that in time ; for, 
as in the present condition of oiu- planet, no portion of its surface 
seems destitute of Infusorial life, so, it Avould appear, from the pi'ose- 
cution of microscopic ix-scarch in connexion with geological facts, 
that, under this simplest, this primary- form, organic life made ita 
fii'st appearance on the globe. Thus, siliceous microscopic beings are 
discoverable in the oldest rocks above the igneous, and, in many 
instances, such beings woxild seem to have played a most important 
part in the building up of strata. Much of the silica of flint 
originates from the siliceous cases of extinct Bacilhria, and even 
porphyritic rock, raised by volcanic or ig-neoua agency, is not devoid 
of examples of such beings. 

Thus, through the many epochs of this world's history, during 
which its surface has undergone the mightiest changes, Infusorial 
life has been sustained ; and so surprisingly so, that forms which now 
exist, had their specific or their generic types at the very dawn of 
organization. This implies the extraordinai-y capability of the 
Infusoria to preserve life, as also their no less wondei'fiil power of 
multiplication. Yet, notwithstanding the conservative and repro- 
ductive power of microscopic life, and its consequent capacity for 
almost unlimited diffusion, some definite law is manifest in many 
cases of geographical distribution. 

The untiring industiy of Professor Ehrenberg, in examining recent 
and fossil specimens, sent to him from almost every known region of 
the globe, has disclosed the fact, that although some species are 
cosmopolitan, not a few may be taken as characteristic of certain 
geographical areas. To give an example, we may quote from a 
recent paper, read by that great microscopist, before the Berlin 
Academy, on a very extensive layer of siHceous Polygastrica in 
Oregon : — "The chain of rocky mountains traversing the continent 
of North America, forms, -with reference to the distribution of 
Infusoria, a stronger barrier between California and Oregon, and the 
rest of the continent, than does the Pacific Ocean, with China, 
between the Western Plains of North America, and the Region of 
Siberia. Thus, the United States, with Mexico, never present any of 



64 GENTlnAL HISTORY OF 

the forms characteristic of Oregon and California; whilst, on the 
other hand, the peculiar forms of these latter countries are met with 
in Siberia. All this is remarkably confinned in this, that the gold 
region of the Sacramento, in the extent and abimdance of its 
Infusorial products, finds its parallel only in Siberia." (Monatsbericht, 
Berlin Acad. Feb. 1849.) 

Most of the preceding remarks apply with greater force to those 
siliceous shelled microscopic organisms included in the great family 
Bacillaria. It is these beings which at previous eras have built up 
rocks, raising land from the sea bottom, and which now, by their 
indestructibility, admit the extensive review of their distribution in 
time and space made by Ehrenberg. "Whereas the illoricated, soft, 
and evidently animal Infusoria, have, by their destructibility, been 
removed from the sphere of our investigations into their diffusion 
in past time. Yet sufficient has been made out to indicate the pre- 
valence of a law of distribution in space even in their case. 

The determination of species characteristic of certain climes, has 
enabled Ehi-enberg to arrive, in many cases, at the probable source 
of those meteoric showers of dust which occasionally occur. For 
instance, those which fall in the Atlantic about the Cape de Verd 
Islands, and as far eastward as Genoa, Malta, and other districts of 
Southern Europe, are found to be made up from l-3rd to l-6th of 
organic matters, chiefly of Polygastrica ; and although most of the 
species alike occur in the most widely separated places mentioned, 
and are of fresh water habit, yet there are others of limited and 
special distribution. Thus the Sirocco dust, which fell in Genoa in 
May, 1846, contained Synedra Entomon, a characteristic South 
American form, along with African species ; the latter, however, 
being in no greater quantity than in other dusts falling within the 
limits above spoken of. Erom this, Ehrenberg surmises that there 
is a curi'ent of air uniting Africa and America, in the region of the 
trade-winds, and occasionally directed towards Europe. 

In the various kinds of meteoric dust, Ehrenberg has determined 
no less than 320 specific fonns of Polygastrica, Phytolifharia, Poly- 
tJialamia, and the soft parts of plants. The predominating genera of 
Polygastrica (marine and freshwater,) are Coscinodiscus, Biploneis, 
Goniothecium, Grammatophora, and Biddulphia. In Ehi'enberg's 



IKFUSOEIAL ANIMALCULES. 65 

elaborate paper entitled " Passatstaub und Blutregen," (folio, 1849, 
Berlin,) is presented a complete history of the showers of meteoric 
dust, &c., which are on record, and the microscopic analysis of the 
various specimens which he has procured. 

It happens with the Polygastrica, as with all other classes of 
organized beings, that some families and genera are much more 
widely diffused, and of more common occurrence than others. Every- 
where, where there is decomposing organic matter in water, Vibriom'a, 
Monadina, and Lemophrys, will be found. Examples of the genera 
Vorticella, Vblvox, Paramecmm, Kolj)oda, Oxytriclm, and Euplotes, &e., 
are common in ponds and strcams at all parts of the world, and often 
in great numbers. Equally widely diffused are the two sections of 
the family Bacillaria — Besmidiem and Diatomacece, the latter is pro- 
minently cosmopolitan, and, in the abundance of its members, unsur- 
passed. (See Part III.) Of the last section, the richest genera are 
Eunotia, Navicula, Stirirella, Pinnularia, Gomphonema, Cocconeis, 
Stauroneis, Actinoeyelus, Gallmiella, Bictyocha, Synedra, Coscinodiscus, 
and Schizonema. 

We have several times alluded to the abundance of fossil Diatomacea, 
which sometimes constitute the almost sole ingredient of masses of 
rock or earth ; as, in the mountain meal {Berg-mehl) ; in various 
polishing powders ; in the piire siliceous sand employed in the manu- 
facture of porcelain, &c. And, inasmuch as any particular fossil 
deposit, generally, possesses some peculiar species, or a particular 
collection of species, it has happened that the antiquaiian has been 
able to determine, that various ancient articles of pottery have been 
made from the particular layer of clay in their vicinity, or, other- 
wise, have been brought from a distance. 

Section XIX. — Of the Rotatoria as a class, and of their habits 
and movements. — This tribe of beings possesses so complete an organi- 
zation, that in a correct arrangement of the animal kingdom, it 
would take its station far above many others, whose members are of 
much larger magnitude. 

The comparatively large size of the Rotatoria, and the transparency 
of their integument, have enabled the microscopic observer to ascer- 
tain with certainty, in many cases, every part of their internal 



f56 GENERAL HISTOET OF 

Btnicture. As a tribe, it is evidently more natural than that of 
the Polygmtrica ; at least there are no such doubtful families as wc 
find in the latter, namely, the Closterina, BaciUaria, &c. Indeed, 
the only exception, that can probably be taken, is the genus Btvphano- 
ceros, which some naturalists class along with the Zoophytes. 

The Rotatoria (sometimes spoken of also as Rotifera) are symme- 
trical beings, and derive their name from the apparent whirling, 
wheel (rotayVikB motion of their rotatory apparatus, when set in 
action; but since, in some instances, the apparatus is so modified 
that a wheel-like motion is wanting, another appellation has been 
contrived — viz., SystoUdes, to designate these animals. It is from 
the very contractile character of their bodies that Dujardin so terms 
them ; and, indeed, some other name than Rotatoria is requisite, if 
this naturalist be followed in introducing in the class various 
animals, furnished with rudimentary hmbs, in pairs, but wanting a 
rotatory apparatus, and, generally, so modified in structure, as to be 
fitted for a parasitic existence within the bodies of other animals — 
such are the members of the family Tardigrada, (DuJ.) 

In such an aiTangement, Mr. Adam White seems disposed to agree 
with the French naturalist, for he has stated it as his opinion, 
"that the so-called Acarus folliculorum, and, probably, also Tardi- 
grada, are parasitic Rotatoria, vnth legs or leg-like appendages 
adapted to their peculiar habits ; and that their retractile antenna- 
like, sub-telescopic appendages, may have eyes passing through them 
as in snails, and may also be the equivalents of the rotce {rotary lobes), 
but from the limited, or rather the absolutely restricted power of 
motion of these animals, have neither the ciliary processes, nor the 
movements and economical uses of the appendages so characteristic 
of most of the Rotatoria^ (Read before the Linn»an Society, June 
1851. See Ann. Nat. Hist., vol. vii. p. 424.) 

The Rotatoria are microscopic objects, although many of them are 
visible to the naked eye as floating specks. They are specially in- 
habitants of pure water, not occurring in infusions, unless of very 
recent plants, in which decomposition has not begun. For instance 
, sagt^-lcavcs, clover, or chopped haj^, are often put to macerate in 
water, in order to prociu'e specimens of Rotatoria ; the appearance of 



INFtrSCEIAL ANIMAICTJLES. 67 

which, under such circumstances, we may consider due to the exist- 
ence of their eggs, upon, or about such vegetable matters, or to the 
presence of the animals themselves in a dried state. 

The Rotatoria especially delight to live in still water, among 
growing aquatic plants, such as Conferva, Letmia, Ccratophyllum, 
Hottonia, «&c., to which they frequently adhere. They inhabit both 
fresh and salt water, but are more numerous in the former. 

Immersion in water is, however, not necessary to their existence; 
for they are to be found also in damp or moist earth, as in the 
earthy deposit from the rain-water spouts of houses, in the detritus 
of walls, roofs, &c., upon mosses and Lichens, such as the tufts of 
Bryum, and about the mosses groT\dng on the roots of trees, such as 
the Hypnum. From such plants as mentioned, they may be sepa- 
rated, by washing with a little water. 

It is a curious fact, however, that they sometimes establish their 
residence within the cells of mosses and Algae, where they are apt 
to be made prisoners in the progress of growth of the plants. 

Their capability of being completely dessicated, and of being sub- 
sequently revived, has been previously spoken of in Section VIII. 
Ehrenberg has seen, in the Hydatina, life prolonged eighteen to 
twenty days; but its duration will greatly depend on the circum- 
stances of temperature, &c., imder which the Rotatoria are placed. 
By far, the majority of Rotatoria have the power of locomotion, but 
several genera form exceptions, their members mostly being fixed 
by means of a conti'actile pedicle. 

These attached forms are enveloped by an outer tubular case, 
within which, they can entirely withdraw themselves by means of 
their pedicles, or, from which, they can extrude the greater part of 
their body, when in search of food ; they thus enjoy a certain lati- 
tude of motion, suitable to their peculiar condition. 

The locomotive Rotatoria, on the other hand, exhibit great activity 
and variety in their movements. The greater number swim along 
in a uniform manner, by means of the ciliated rotary organ ex. Bra- 
chionus ; others, in addition, crawl like leeches, by alternately 
advancing, and using as fixed points, the head and the suctorial 
extremity of the tail, ex. Rotifer ; whilst a few skip or leap after 

F 2 



68 GENEKAL HISTORY OF 

the manner of the Daphnia or water-fleas, by the action of bristle- 
like appendages, ex. Triarthra. 

On these varieties of the movements of Rotatoria it is, that 
M. Dujardin bases his primary divisions of the class. 

Section XX. — Of the External Coverings, of the Muscular System, 
and of the Organs of Locomotion of Rotatoria. — The external surface 
of Rotatoria is made up of a smooth and firm integument, more 
delicate at the anterior extremity or head of the animals, where it 
becomes ciliated. Its contractions coincide with those of the sub- 
jacent parenchyma, whence it is not drawn into folds. In many 
instances the integument presents transverse or circular markings, 
indicating the division of the body into segments, as in the Crustacea. 
The usual smooth condition of the integument is departed from in 
the genus Choetonotus, (figs. 357-358) and in Philodina aculeata, (figs. 
487-489) the surface is strewed with stiff bristles and styles — ^whilst 
that of Noteus (figs. 491-494) and of some Anurwa, is roughened by 
granular eminences. 

The caudal extremity exhibits the transverse wrinkles most 
strongly, and in many cases is clearly divided into segments, as in 
Conochilus, (figs. 365-370) Megalotrocha, (figs. 374-375) Lacinula/ria, 
Noteus, &c. In various species of Hydatina, Rotifer, Eosphora, 
Philodina, &,x., not only the caudal portion, but the rest of the body, 
is also divided into segments, which will slide upon one another Like 
the tubes of a telescope. 

A rigid horny shield, resembling, in structure, that of Daphniae, 
is met with in Brachionus, Anuroea, Noteus, &c. Within the outer, 
firmer tunic, Mr. Gosse describes an inner, softer one, into which the 
muscular cords are inserted. (See those families.) 

Some Rotatoria possess, besides the integument immediately in- 
vesting them, another external to it, and surrounding it in the form 
of a sheath, to the bottom of which they are fastened. This sheath 
(urceolus) varies in kind as well as in form ; thus, in Lacinularia (fig. 
378) it is gelatinous, and the animal imbedded in it; in Melicerta, 
(figs. 386-387) the animal can move freely within its gelatinous 
case, which is here strengthened by adherent foreign particles, the 
same, in a less degree, obtains in Oecistes (fig. 362) ; and in Zinmiaa, 



INFTTSORIAL ANIMAT.CTTtES. 69 

(fig. 388) ; whilst the caf;cs of Flosmla/ria, (fig. 384) Tulicola/ria, (fig. 
379) and Stephanoceros, (fig. 383) are loose and hyaline. 

These outer gelatinous and tubular sheaths, are clearly, products 
from the animal, which secretes them, as the coral-animals do their 
cells, or the mollusca their shells. (See Mclicerta and Tlate XXIII.) 

In the genus Clmtonotus^ Dujardin even denies the existence of a 
proper integument, and ranks it with the Polygastrica. (For a 
summary of the external processes of Rotatoria, see Section II.) 

In this class, a muscular system, subservient to the functions of 
locomotion, nutrition, &c., is well developed, and the integuments 
being transparent, its sti'ucture and disposition are distinctly visible 
imder the microscope, without dissection. The principle muscular 
member is a foot-like non- articulated process, situated on the ventral 
surface of the posterior part of the body. This member is usually 
called the tail ; but being situated anteriorly to the discharging orifice, 
is not properly such. It has usually the faculty of being able to 
slide one part within another, and recalls to the observer the move- 
ment of the sliding tubes of an opera-glass, or telescope. Its 
extremity is often so formed, that the creature can cause itself to 
adhere to any substance, by probably producing an exhausted cavity 
within the disc-like extremity, as do the leech and some parasitic 
acari found on beetles. Sometimes the termination of this false foot 
has two or more toe-like processes. By the construction of this 
member, the creature is enabled to attach itself, while the anterior 
part is moving about in search of provender, and likewise to employ 
it as an instrument of progression, by alternately contracting and 
elongating it, and fixing itself by it and the mouth, after the manner 
of a leech. Muscles for moving the body, and the rotatoiy organs, 
are mostly visible ; they are known by their thickening during con- 
ti'action, and by dilating when elongated. 

"With reference to their arrangement, the muscles form two sets — 
the one, annular, encompassing the body; the other, longitudinal. 
The former are separated from each other by considerable intervals, 
and give to the body the appearance of being divided into several 
transverse segments. The longitudinal muscles arise from the in- 
tegument, and proceed forward to be attached to the oesophageal bulb, 
or to the rotaiy apparatus, or else backwards to the tail, with its 



70 6ENEBAI HI8T0EY OF 

several eliding segmonts. Very fine muscular threads ore likewise 
employed to keep the viscera ia their places; and some transverse 
ones crossing the general ca\'ity of the body, have, in some instances, 
been seen. (Plate XXIII, fig. 5.) 

Mr. Gosse says: "AU the cuticular insertions (of the muscles) 
are in a skin separable from the outer integument. . . . The coronet 
of thickened masses that surround the head is probably muscular, 
bearing the cilia. Just below this (in Asplancha priodontn) there is a 
series of five or six annular threads, set in the inner skin, which are 
probably muscular, and aid in the complex movements of the head. 
The reniform cushion that bears the jaws, is, doubtless, composed of 
powerful muscles ; and the delicate stomach with its tube, the great 
crop and the ovisac, are covered with a muscular network." 

The muscles of the Rotatoria have a clear, distinct outline, but 
are not transversely striated, and belong to the imstriated muscular 
tissue of anatomists. 

Dujardin (Histoire des Infusoires, p. 557) is the only recent 
writer w© have met with, who denies the existence of distinct 
muscles in this class. He would attribute the movements witnessed, 
to the operation of a soft, diaphanotis, diffluent substance, subjacent 
to the integument, which he further supposes to possess an inherent 
property of contractility. This same author excludes the genus 
ChcBtonotus from the Rotatoria, under the impression that it does not 
present the characteristic contractility of the class, and, above aU, 
that it has no true rotary organ. 

The most singular and interesting organ in these creatures, if not 
the most remarkable structure in the animal kingdom, is the so-called 
rotary or rotatory organ ; it consists essentially of a whorl of cilia, 
seated on a contractile base, forming the head of the animals. It 
constitutes the piincipal means of locomotion, the tail process being, 
in most cases, less concerned. Even where the animal, by the alter- 
nate fixing of its mouth and tail, can progress like a leech, it can, 
also, more rapidly advance by the propulsion of its ciliated wheel 
apparatus. 

The rotary movement of this apparatus was, at one time, looked 
upon as a reality, but is now regarded as only ajiparent. Dutrochet 
attributed the phenomenon to the undulation of a delicate membrane 



INFUSORIAL ANTMALCULES. '71 

fringing the head of the Rotatoria. Ftiraday explains it by sup- 
posing the distinct cilia to become visible by slowly returning to 
an erect state, after having been suddenly bent pre vioiisly. Ehrenberg 
again assumed the existence of four muscles at the base of each 
cilium, each acting upon it in its own direction, and so producing a 
revolution around the fixed point of attachment or base of the 
cilium. In this way each cilium would be alternately nearer to, or 
more remote from the eye, and, consequently, more or less visible. 

Another explanation has been offered by Dujardin. He says, 
" The vibratile cilia being arranged parallel, and at equal distances, 
will equally refract or intercept the light, and none will be more 
visible than the rest, but if, by a movement propagated along the 
row of cilia, some, momentarily inclined, are brought into juxta- 
position with adjoining cUia, the light will be more intercepted, and 
a band, more or less dark, will be the result. It can be imagined, 
therefore, that if the cilia come to be inclined one after another, a 
series of juxta-positions, or of apparent intersections, will be pro- 
duced, and this, in the direction of the general movement. Further, 
if each of the intersections preserves the same form as if produced 
by a number of equal lines, and are equally inclined to each other, 
an appearance of a solid body of a definite form, like the tooth of a 
saw or the spokes of a wheel, moving uniformly, presents itself to 
the eye." 

The situation, number, and disposition of the rotatory organs, are 
employed in the grouping of the Rotatoria into families and genera. 

The rotary apparatus is single, double, or made up of several 
portions. Its wheel-like motion is most evident where the rotary 
apparatus forms an unbroken circle, as in Conochilus, (figs. 365-370) 
Philodina, (figs. 487-490) and Actinurus, (figs. 481-484.) Where 
the apparatus is interrupted by a notch, and is made up of two or 
more smaller distinct wheels, the delusion of complete revolutions is 
removed, as in Hydatina, (fig. 394) Notommata, (figs. 418-420) 
Diglena, (figs. 403-405), &c. Exceptional forms are exhibited in 
Floscularia and Stephanoceros. 

The action of the rotary apparatus may be arrested at the will of 
the animal, or the entire organ be retracted within the body. 

In addition to the rotary organ, the head is sometimes crowned by 



72 GENEBAt HI8T0ET OF 

several styliform processes, moveable, but not ciKated ; examples of 
siich organs are to be found in Salpina, (figs. 447-453) Monostyla, 
(figs. 434-437) and Brachionm, (figs. 499-501.) In Floscularia (figs. 
384-385) indeed, five to six lobes, with long radiating cilia, consti- 
tute tbe so-called rotary organ of that animal ; whilst Stephanocerm 
(fig. 383) ofiers a still wider departure from the normal form, in 
having five long ciliated arms proceeding from its head, and no true 
rotary apparatus existing, thus establishing a great affinity, in external 
form, with the Bryozoa, or CUiobrachiate Polypes. 

Although the true Rotatoria are destitute of locomotive members 
on their under surface, yet an approach to such organs is indicated 
in the toes, or pincer-like processes of the tail, before alluded to, as 
attached to its extremity, and sometimes, in addition, to one or more 
of its segments. If the Tardigrada (see end Part III.) of Dujardin, 
be admitted among the Rotatoria, then the latter will comprehend 
animals with distinct, rudimentary legs or feet, by means of whicli 
they can crawl. 

Besides the rotary organ, and the tail with its appendages, other 
special instruments are met with in the stiff-bristles, (cirrhi) of Poly- 
arthra (figs. 401-425) and Triarthra (figs. 406-408), in the former, 
fixed on each side of the neck, and moved after the manner of oars ; 
in the latter, articulated on the under surface of the body, and giving 
the animal a very active leaping movement, Hke that of a flea. 

The true telescopic tail is wanting in several genera and species, 
as Anuraa; others have a short pincer-like process, as Clvxtonotus, 
(figs. 357-358) Eosphora, (fig. 415) Cycloglma, (figs. 425-426), &c. ; 
others, two long styliform processes, as Notommata longiseta, (fig. 421) 
N. Felis, &c., whUst others again have a single style of greater or 
less length, as Rattulus, (fig. 409) Monocerca, (fig. 399-417) Mo- 
nostyla, (figs. 434-437) and Mastigocerca, (fig. 438-440.) 

But besides the locomotive Rotatoria, there are fixed forms, many 
of which have a posterior prolongation, rather deserving the term 
pedicle or stem, than that of tail or foot-like process. This pedicle 
is contractile throughout, or only in part, corrugating itself, and 
having no sliding segments ; examples are seen in Tuhicolaria, (figs. 
370-382) Stephanoceros, (fig. 383) Limnias, (fig. 388-392) and Meli- 
certa, (fig. 386-387.) The contractility of the foot enables these 



INFUSOniAl ANIMAICTTIES, 73 

fixed Rotatoria to withdraw themselves within the investing sheath, 
or tube, within which they live, after having previously extended 
themselves beyond it. 

Dr. Dobie, in his account of the species of Flosculwria, describes 
their " ciHa as of two kinds ; one of the usual short vibratile kind, 
covering the interior of the alimentary tube ; the other, extremely 
long and filiform, of uniform thickness and not vibratile under ordi- 
nary circumstances. They are slowly moved, and spread out by the 
contractile substance of the lobes of the rotatory organ." He adds, 
" when a solution of caustic potash is brought in contact with the 
filiform cilia, a most violent vibratile action immediately commences) 
and continues till the whole bundle is completely disorganized. 
Violent mechanical stimulation seems to have a similar efiect, though 
in a less degree." 

The form of cilia, described by Dr. Dobie, on the rotary apparatus 
of Floseularia is exceptional, the general kind, imparting the sur- 
prising locomotive power of the organ, being short and actively 
vibratile. (See Wood Engraving, Part III.) 

Dr. Dobie found "immediately below the integument of Floscu- 
laria cornuta, groups and lines of very small granules, continually in 
a state of rapid molecular motion, in appearance, exactly resembling 
the molecules in the cusps of Clostermm. Besides the molecular, 
they are subject to another motion, for occasionally they move from 
one part of the surface to another, in currents not very distinct or 
persistent, and in no definite direction. He has seen them running 
in lines down the tail, and collecting in groups. This flowing move- 
ment occurs chiefly during the contractions and relaxations of the 
entire animal. He thinks it probable that these granules are con- 
nected with the nutrition of the animal, and analogous to the free 
floating corpuscles of the Tardigrada, described by M. Doyere." 
(Ann. Nat. Hist. 1848, p. 233.) 

Section XXI. — Of the Digestive System of Rotatoria. — The 
Rotatoria possess a distinct and undoubted alimentary canal, evident 
as a tube traversing their interior, from the mouth to the posterior 
outlet, having a certain definite position, and absent in only a few 
instances. 

Food is drawn into the mouth, by means of the vortex, occasioned 



74 OENEBAL HTSTOBY OF 

by the action of the curious rotary organ, (described in the last 
section) wbicb surrounds that opening. It, first of all, enters a short 
cavity, known as ' the crop,' and is then submitted to the action of 
homy jaws, mostly armed with teeth, and enclosed in a powerful 
muscular apparatus, forming what is called the oesophageal head, 
or bulb Separate drawings of this bulb, with the different arrange- 
ment of the teeth, are shewn in figures 377, 382, 383, 396, 420, 
424, 433, 437, 444, 455, and 456. It next passes thi'ough a canal, 
the oesophagus, into a dilated space, termed the stomach, and, after 
due digestion, is propelled thence, through an intestine, to the 
outlet. 

The whole course of the alimentary canal is mostly straight, but, 
in some Rotatoria, for instance, in Tubicolaria and Melicerta, it 
presents a slight coil. The canal is Hned by vibratile cilia, which 
assist in the introduction and propulsion of food. 

The portion of the alimentary tube, immediately posterior to the 
mouth, is funnel-shaped, and hence, called by Dr. Dobie, the infun- 
dihulum, having its edge frequently divided into lobes, (see fig. .) 
This space is separated by a rim, armed by non- vibratile cOia, from 
the next portion, called, by M. Dujardin, \hQ vestibule ; and which 
leads into a very dilatable cavity, called the crop, a fissured partition, 
or diaphragm, intervening between the two. The crop ends below, 
in, or in some measure, contains the oesophageal bulb, with its usual 
armature of teeth, supported on horny jaws, and separable by 
pressure. 

This manducatory, or chewing apparatus, has been compared to 
the gizzard of birds, which it resembles in function, but is, otherwise, 
more like the crushing toothed apparatus, in the stomach of crabs, 
lobsters, &c. The number, form, and arrangement of the teeth, 
afford excellent characters for the systematist ; and will be found 
figured, in the case of many genera, as referred to above. 

In most instances, the oesophageal bulb, although enjoying con- 
siderable latitude of motion within the body, does not project from 
it; but, in some single-toothed forms, ox-JBrachiontis, with the 
rotary organ divided, this bulb protrudes beyond the mouth, and 
thus becomes a prehensile organ, using its teeth like claws or 
pincers. 



INFUSORIAL ANIMALCULES. 75 

Tho jaws supporting the teeth, arc of a homy consistence, and arc 
mostly furnished with two bent geniculate processes, one anterior, 
the other posterior, in position. These processes serve for fixing the 
jaws more firmly in situ, and, in addition, furnish powerftQ leverage 
for the muscles working them. The jaws are further complicated 
in some many-toothed Rotatoria — such as Philodina, Lacinulwria, 
Melicerta, by the development of arches to support the teeth. 

The rubbing together of the opposed surfaces of the horny jaws, 
may be readily observed, and a sort of peristaltic contraction, nearly 
incessant, is also noticeable in the oesophageal bulb, which surrounds 
the jaws as a muscular investment. The peristaltic contractions of 
the bulb, led the older observers to entertain the idea that it was a 
heart — the contractions representing its pulsations. 

The oesophageal bulb and teeth are the first perceptible organs iu 
the embryonic Rotatoria ; and a backward and forward, or peristaltic 
motion, may be noticed in the bulb, even before the escape of the 
young animal from the e^^. 

In Chatonottis, this characteristic manducatory organ of the 
Rotatoria is not distinguishable, and, most likely wanting : — for this 
reason, as well as others, elsewhere named, Dujardin excludes this 
genus from the order. 

Beneath the oesophageal bulb, 'the digestive tube undergoes another 
enlargement, constituting a stomach — the connecting narrower por- 
tion interposed between the two, being generally known as the 
oesophagus. Mr. Goss, unfortunately, however, applies the term 
oesophagus, to the first portion of the alimentary canal, between the 
mouth and crop ; but the preceding application is more usual. (Des- 
cription of Asplanchna, — Ann. Nat. Hist. 1850.) 

The oesophagus varies much in length, in difi'erent Rotatoria; 
and very great difi'erencea are observable in the degree of develop- 
ment of the stomach ; for, in some genera, the digestive tube con- 
tinues as a simple, funnel-like tube, into its termination, in which 
case, consequently, a stomach cannot be rightly said to exist, whilst, 
in others, on the contrary, the stomach is a considerable cavity, and 
not unfrequently sacculated. 

The canal narrows again below the stomach, forming an intestine, 
the rectum varpng in length in diifcrent species, and ending by a 



76 GENERAL HI9T0EY OF 

very dilatable portion, opening externally, and which, from serving, 
also, as a conduit for the eggs (in the female,) is analogous to the 
cloaca of birds. It always opens at the base of the footlike tail. 

Every portion of the alimentary tube, except the muscidar bound 
oesophageal bulb, is capable of great distension ; and this is particularly 
noticeable in the crop, stomach, and cloaca, in the last, during the pro- 
cess of oviposition, the eggs of Rotatoria being of very large size. 

A very curious exception to the general rule, of a digestive inlet 
and outlet in Rotatoria, has been observed by Mr. Gosse, in the 
genus Asplanchna, for it has "no anal orifice, nor any intestine 
below the stomach ; the remains of the food, when digested, are 
regurgitated by the contraction of the viscera, and discharged 
through the mouth," as ia Polypes. 

Special organs of secretion exhibit themselves in this class, under 
their simplest form, as sac's, or cells containing coloured fluid, and 
opening into the alimentary canal. Attached to the oesophagus, or 
to the upper part of the stomach, is a pair of glands, usually of an 
oval form, but sometimes, though rarely, cylindrical or forked, and 
considered by Ehrenberg, to represent the pancreas. Besides these, 
coloured sacs, with yellowish brown, or greenish granular contents, 
are often to be seen external to the stomach and intestine, into which 
they pour their secretion by gall-ducts — as Ehrenberg thinks is 
evident in Enteroplea — the secreting cells themselves being the liver, 
on biliary glands. Siebold states that the pancreatic glands are absent 
in the Idhydina; whilst in some species, as Notommata clavulafa, 
Biglena lacustris, (fig. 403,) and MegalotrocJia albo-favicans, (figs. 
374-376), they are complicated by additional sacs or tubes. 

In Asplanchna, Mr. Gosse describes " several yellow glandular (?) 
spots, varying in number," on the top of the cushion of the oesopha- 
geal bulb. In Floscularia campanulata, Dr. Dobie observed large 
fixed granules distributed here and there, throughout the body and 
tail, most nearly resembling globules of oil. 

The glandular bodies concerned in the process of reproduction are 
described in the section devoted to the consideration of that process. 

The preceding account of the digestive system of Rotatoria, 
applies, in the main, to the females only ; the recent discovery of the 
male Rotatoria, has also shewn an organization, peculiar to them- 



INFTTSOETAl ANIMAICUIES. 77 

selves, but far inferior in type, to that of the females, in every 
structure, save that devoted to the continuation of the species. 

The discoverer (Mr. Brightwell) of the male beings, could distia- 
guish no jaws, gullet, stomach, nor hepatic organs, and, indeed, no 
appearance of extraneous matter being received into the body. Mr. 
Gosse, in describing the male Asplanchna, says : — " the place of the 
stomach was occupied by a long sac, having a slender neck, origina- 
ting from the fi'ont part of the head mass, and, at the bottom, 
broadly attached to the sperm-bag." (Plate XV, fig. 65, 66, and 
Plate XXIII, fig. 7, 8.) 

Section XXII. — Of the Vascular and Respiratory system of the 
Rotatoria. — The vascular system in these animals, according to 
Siebold, is most probably one circulating only water, and which, by 
its organization and character, must be also considered to serve a 
respiratory purpose. There exists, for instance, in most Rotatoria, 
on each side, a small band-like organ, through which an apparent 
vascular canal winds. At the anterior extremity, these two side 
bands, with their contained vessels, become connected with other 
short lateral vessels, which open directly into the abdominal cavity, 
having their orifices fornished with fi-eely oscillating or vibratile 
flaps. The number of vibratile orifices varies in different species, 
and, it would appear, even in different individuals of the same 
species. Usually, two or three are met with on one side, and from 
five to eight on the other ; but, in not a few, a much greater number 
exists, as in Notommata clavulata, and JS". myrmeleo, while in the 
genus Flosmlaria, Dr. Dobie states the tremulous giU-hke organs to 
be absent. (Plate XXIII, fig. 6, 9.) 

At the posterior part of the body, the two side bands approach 
and unite in a common thin- walled trunk or contractile sac, which 
by its active contractions, forces out its fluid contents through the 
cloaca! opening. 

In the neck of most Rototaria, is also placed a projecting tubular 
process, sometimes two, through which, in aU probability, the water 
enters the interior of the body, and passes into the water-circulating 
system just described. Admitting the tube to have the office 
assigned it, it may be justly called the respiratory tube. Mr. Gosse 
is led to regai'd tubes or processes of this character rather to be 



,78 GENEEAL HISTORY OF 

rudimentary antennae ; and that observer consequently appears to 
agree with M. Dujardin, in questioning their tubular structure. 

The excellent description by Mr. Dalrymple of a new genus 
of Motatoria — Asplanclma BrightweUii, Gosse — (Phil. Trans. 1849, 
p. 334), affords us a very clear account of the circulatory appa- 
ratus, diffeiing in some points from that which we have borrowed 
from Siebold. He says, " This peculiar organ consists in a double 
series of transparent filaments (for there is no proof of their being 
tubes or vessels), arranged, from above downwards, in curved or 
semicircular form; symmetrical, when viewed in front. These 
filaments, above and below, are interlaced, loop-like ; while another 
fine filament passes in a straight line, like the chord of an arc, 
uniting the two looped extremities. To this delicate filament are 
attached little tags, or appendices, whose free extremities are directed 
towards the interior of the animal, and are afiected by a tremulous, 
apparently spiral motion, like the threads of a screw. This is 
undoubtedly duo to cilia arranged round these minute appendices. 
The tags are from eight to twelve, or even twenty, in number, 
varying in different specimens. (Plate XXIII, fig. 6a.) 

"I beKeve the organ in question to be a peculiar circulatory 
system. The body of the animal is filled with fluid, most probably 
analagous to blood, while the ciliated tags, in perpetual motion, must 
produce currents in this fluid, and probably in an imiform and 
determinate direction. In this way the nutrient plasma will be 
brought regularly in contact vrith all parts of the body, and the 
process of nutrition go on as in insects, without the intervention of 
tubular vesssels, the dorsal heai't, in them, serving only to give 
direction and circulation to the blood. I am the more impressed 
with this belief, since these filamentous organs are in close approxi- 
mation with the large contractile sac, which probably performs a 
respiratory function." 

Por it win be seen, from the following extract, that Mr. Dah-ymple 
does not believe in any communication between the sac and the 
apparatus furnished with the ciliated tags, as Siebold supposes ; on 
the conti'ary, the former vsniter makes the sac to communicate 
directly with the exterior. He writes, " This sae, spherical when 
distended, is placed just above the ovisac, and communicates ij\dth 



INFTTSOEIAI ANIMALCULES. 79 

the vaginal canal. It is exceedingly delicate, and may be seen to 
conti'act, by the action of muscular fibres, with great rapidity, in 
which act it is thrown into numerous regular folds or pouches, and 
in that condition appears not very dissimilai' to the large cellular 

lungs of Batrachia The explanation which I ventui-e to 

give, is, that this sac draws in water and expels it again by the 
vaginal orifi.ce ; and it is by bringing the blood, by means of the 
ciliary movements of the tags, into intermediate contact — (the 
delicate membranous wall of the sac intervening) with the air of 
the water, that aeration or respiration is performed. An analogous 
contractile sac may be seen in Rotifer vulgaris y 

Elirenberg described the several organs discussed, assuming the 
existence of a respiratorj^ apparatus, evidenced in the tremulous tags, 
and which ho designated gill-like organs, or gills. His views are 
represented by the following abstract : " Oval tremulous bodies are in 
some species, observed attached to a free filament-Hke tube, generally 
placed longitudinally within the body, (fig. 416) ; in some instances, 
they are attached to the two sexual glands, as in Hydatina. Their func- 
tion is respii'atory, and they are analagous to gills ; the tremulous 
motion observable, being that of the lamina composing them. The 
reception of water within the body, for these organs to act upon, is 
provided for, by one or more openings at the anterior part of the 
body, furnished, in some species, by spur-like processes, or tubes," 

The aimular cords, producing the semblance of articulations in the 
body of many Rotatoria, were surmised by Ehrenberg to be vessels, 
but, as before stated, the general opinion is that they are muscular. 
In some examples, he also described the vessels to form a net- work, 
more or less distinct, below the margin of the mouth, and connected 
by free longitudinal cords to the interior sxxrface of the body. (pi. 
ix. fig. 419). 

No naturalist has yet confirmed such a vascular network, as is thus 
figured and described ; but various delicate muscular threads are 
known to cross one another, about the neck of these animals, as they 
pass to theii' insertions in the muscular cushions forming the rotary 
apparatus. Thus, Mr. Gosse says : " thi-eads with biftu-cate extreme- 
ties go from the centre of the head to each cone-top (of the rotary 
organ), each lateral eye, and each antenna." Dr. Dobie also speaks 



80 OENEBAt HISTOEY OF 

of muscular bands in the same position, passing to the centre of the 
depressions between the lobes of the head of Floscularia campanulata, 
and of lines of a fainter description, running up the centre of each 
lobe, to near its apex. 

We are enabled to give an independent description of the gill-like 
apparatus in the neck, from Mr. Gosse's admirable account of the 
Asplanchna priodonta. He writes : "On the upper side of the 
oviduct sits a contractile bladder, which, when full, is perfectly- 
globular and small; being scarcely, if at all, larger than the two 
pancreatic glands put together. Round this, attached at or near its 
base, passes on each side, a tortuous thread, apparently glandular, 
which goes up along each side of the ventral region, and is attached 
to the head-mass behind the jaw-cushion. The middle part of each 
thread is wrinkled into a large plexus of four or five pairs of doublings, 
laid with some regularity ; on this plexus are placed four tremulous 
tags, directed inwards ; making eight in aU. None are visible on 
any other part of the threads. The presence of these organs, as well 
as of the contractile bladder, in the female, shows that these are not 
connected with impregnation. Close to each plexus there is a minute 
orifice in the skin, set around with short setae, and a similar one is 
placed on each side of the back, but a little higher up. From each 
of these four apertures, a thread, floating freely in the cavity of the 
body, goes towards the head, having, at its contact with the aperture, 
a thickened club-shaped ganglion or gland." 

"We have assumed that this description applies to the gill-like, or 
respiratory apparatus, of Ehrenberg, or the * water circulating system' 
of Siebold; for to no other structures can the 'tremulous tags,' and 
their accompanying * tortuous threads' of Gosse, in our opinion, refer. 
Hence, if our assumption be correct, Mr. Gosse appears to believe in 
the glandular nature, at least of the tortuous threads, of those organs, 
and thus, in some degree, to countenance the first hypothesis of 
Ehrenberg, respecting their glandular ofiice; the latter, however, 
supposed them spermatic glands, or vesiculae seminales ; but as Mr. 
Gosse remarks, they are evidently not connected with impregnation. 
The contractile sac which Ehrenberg surmised to be spermatic, Mr. 
Dakymple says he is convinced, from repeated observation, has no 
relation to the generative function ; and, as we have seen, attributes 



INFTT80KIAL ANIMALCULES. 81 

to it a respiratory office. He adda, " The supposed vascular ramifi- 
cations upon it, are neither more nor less than the muscular fibriUae 
by which the contractions are effected." 

Section XXIII. — Of the Organs of Sensation and Nervous System 
of Rotatoria. — The Rotatoria arc not considered to possess a true ner- 
vous system, but ia many of the species, having eyes, there appears 
one or two masses attached to them, which Ehrenberg thinks are 
similar to nervous ganglia and nervous fibrillse. The eyes vary in 
number ; they are usually of a red colour ; in some they are placed 
upon a ganglion, and are freely moveable beneath the transparent 
superficial envelope of the body. 

The visual organs are of small size, but always sharply defined, 
and, it would appear, invested with a homy capsule in some cases. 
The firm capsule is observable in ConocJiilus, Rotifer^ and Philodina. 
Dujardin opposes the opinion of the visual character of these red 
specks in Rotatoria, chiefly on account of their not uncommon dis- 
appearance in the adult state. But as Siebold remarks, an objection 
raised on this circumstance is not valid, since a similar phenomenon 
is known to take place in the adult condition of parasitic Crustacea, 
the visual character of whose eye- specks or ocelli is not questioned. 
Moreover the coloured specks in Rotatoria are sharply defined, and 
in some cases at least, furnished with capsules, thus differing totally 
from the non-capsular, ill-defined pigment masses of Foli/gastrica, 
called eyes. 

It is doubtftd, however, Siebold remarks, whether the dispro- 
portionately large specks, described as eyes by Ehrenberg, in Notom- 
mata forcipata, Synchcct-a haltica, in Cycloglen<i and Eosphoi'a, are other 
than loose aggregations of coloured particles. 

The same author says " there is, in Rotatoria^ a constant group of 
ganglions in the neck, regarded as the central organ of the nervous 
system, from which, nerve-cords radiate on all sides." Over this cere- 
bral centre, the organs of vision are seated, and receive fi-om it their 
special nerve fibres. 

The variable relative position of the eyes is detennined by that of 
the ganglions. The position of the former may be on the neck,- — i. e. 
posterior to the base of the rotaiy organs, or on the fore-part of the 
head, or even in advance of the rotary apparatus. 

(» 



82 GENERAL HISTOEY OF 

In the immature and young state of Eudorina, of Melicerta ringm», 
and of MegalotrocTia alba, &c., distinct eyes are present, wliicli, how- 
ever, disappear vnih. advancing age. 

The sense of touch diffused generally over the body, is especially 
concentrated in the rotary organ, and in the styliform processes or 
comua, so frequently produced from it, which may be deemed analo- 
gous to the feelers {aniennce) of insects. We may presume also that 
the toe-like processes of the foot or tail are more largely endowed 
with sensibility. 

Mr. Gosse describing the AsplancJina priodonta, writes : " Each of 
the three eyes rests on a mass that appears ganglionic ; the clubbed 
masses at the lateral apertures are probably of the same character ; 
and the interior of the body contains a number of very delicate 
threads, floating fi-eely in the contained fluid, which have thickened 
knobs here and there, especially where they anastomose (see fig .") 

Section XXIV. — Of ihe reproductive organs, and the reproduction 
of Rotatoria. — The only method of propagation of Rotatoria is by 
ova, of which they deposit only a few at a time. The size of the 
egg is about l-36th that of the parent, and the young of those in 
which incubation is completed before expulsion is sometimes two-thii'ds. 

Although the Eotatorial Infusoria are not endowed with the 
various faculties of reproduction possessed by the Polygastrica, yet 
their vast increase by eggs only, would astonish most persons who 
have not considered this subject. Ehrenberg informs us that he in- 
sulated a single specimen of Uydatina senta, and kept it in a separate 
vessel for eighteen days, that during this interval it laid four eggs 
per day, and that these yoimg, at two days old, lay a Uke number, so 
that, when circumstances are favoui'able, one million indi^-iduals are 
obtained from one specimen in ten days ; that, on the eleventh day, 
this brood will amount to four millions, and on the twelfth day to 
sixteen millions. Although the fecundity of this Rotatoria is the 
greatest that has been tested by direct experiment, yet (says 
Ehrenberg) in the large Polygastrica, as the Paramecium aurelia, a 
single specimen in one day increases to eight, by simple transverse 
division of the body only ; so that, if we take into this account the 
other modes of the increase of this creatui'c, namely, by eggs, often 
in masses like the spa\vn of fish, and again by buds growing from 



INFUSORIAL ANIJTAICULES. 83 

the sides of the body, it is clear, in a very few days, all attempt at 
an expression of their number must fail. 

The Rotatoria have generally been assumed to be hermaphrodite — 
i. e., that each individual possesses a perfect male and female repro- 
ductive apparatus, by which ova ai'e formed and fructified, without 
the presence or contact of any other individual. Now, in these 
animals, there has never been any difficulty as to the female repro- 
ductive organs, which are very clear, well defined, and can be accu- 
rately described, but, as to the male apparatus, the greatest diversity 
of opinion has existed. 

Dujardin attempts no explanation, whilst Siebold candidly affirms, 
that, with the absence of any precise knowledge as to the male 
organs, it is stiU impossible to say whether the Rotatoria are herma- 
phrodite, or have the sexes separate ; at the same time, he regards 
the hypothesis of Ehrenberg on the subject, as untenable, and opposed 
to probability. 

The clearing up of this questio vexata is, however, due to our 
coimtryman. Mr. Brightwell, of Norwich, from whose discoveries 
it is rendered highly probable, indeed, in part, certain, that the 
sexes in Rotatoria are separate and distinct — existing in distinct 
individuals. This careful observer met with a Eotatorial animal, 
destitute of the internal organization of those heretofore described, but 
having a very evident gland, communicating by an outlet with the 
exterior of the body, the latter, moreover, was produced in some 
measnre as a process perforated by the discharging tube. This 
cuiious animal, of a smaller size than other Rotatoria, Mr. Brightwell 
was at first disposed to consider another species, but subsequent 
examinations, and the observation of occasional attachments with 
the larger and undoubtedly female animals, convinced him, that he 
had discovered a distinct male animal. Subsequent attention to the 
subject has confirmed the fact of the dioecious nature of Rotatoria ; 
and other observers, besides the discoverer, have witnessed the same 
phenomenon. 

No objection can be raised ft-om the fact of the small size and im- 
perfect organization of the newly discovered male animal, for similar 
peculiarities are met with among other tribes of lower animals, such 
as Annelida. 

G 2 



84 OENEEAL HISTOET OF 

This minute male being destitute of organs adapted to continue 
its own existence, is developed solely for the purpose of impregnating 
the lai'ger and more highly organized female animal, of which, 
indeed, it is in part a parasite. 

The female reproductive organs consist of a single or double ovary, 
an ovi-sac, oviduct, and vaginal orifice. The ovary, varies in size, 
having tubes conducting from it to the cloacal outlet, through which 
the ova escape. The ovary is situated at the hinder part of the 
animal, along side the intestine. It is mostly seen to contain ova 
in diiferent stages of development. The mature ova are invested by 
a clear, but firm granular shell, mostly coloured, and containing a 
colourless yolk, with a clear germinal spot. The development of the 
embryo in the egg, proceeds as ia Invertebrata generally, the yoLk 
Bubdividing by spontaneous fission, and, at length, evolving the em- 
bryonic cell. The fully developed embryo is furnished with a 
rotary organ, eye-spots, an oesophageal head, with its masticatory 
apparatus, and, in fact, -with the entire characteristic organization of 
the full grown animal. 

Mr. Gosse, in his paper on AsjjIancJma, says: "In no specimen 
have I seen the ovary horned or band- shaped, but roundish and 
very small." 

The ova, after impregnation, pass from the ovary into the ovisac, 
and there go through various phases of development, like the 
embryo of higher animals in the uterus. When sufficiently advanced, 
the young being escapes into the oviduct, which conducts it through 
the vaginal orifice into the cloaca, whence, after a variable time, it 
IB expelled. 

During the residence of the embryo within the ovisac, it mostly 
becomes enveloped in a sheU, of considerable strength and toughness, 
which preserves it after extrusion from injury. To accommodate 
the increasing size of the contained ovum, or ova, the ovisac is 
capable of great distension, so much indeed, that it sometimes occu- 
pies the larger portion of the interior of the animal. The cloacal 
outlet, also, is very extensible, to allow the temporary retention and 
subsequent passage of the very large matured eggs. In many Hota- 
toria, the ova are not at once set free on their exclusion, but remain 
adherent about the cloaca, as happens in many Entomostraca. 



IJfFUSOEIAL ANIMALCULES. 85 

Again it happens in some species, that the egg shell is dispensed 
with, the embryo being completely developed, so to be able to imme- 
diately commence an independent existence on its escape from its 
parent — in other words, such forms are viviparous : examples ai'e 
met with in Philodina, Rotifer, &c. 

Mr. Gosse writes, of the Asplanchna, that, " the ovum produces 
the li\T.ng young in the ovisac, which, when matiu'ed, occupies the 
whole lower part of the parent .... At length it escapes through 
the o\'iduct and vaginal aperture, and immediately swims freely 
away." 

"The egg of the Hydatina,'" says Dr. Carpenter, "is extruded 
fi'om the cloaca within a few hours after the first rudiment of it is 
visible ; and within twelve hours more the shell bursts, and the 
young animal comes forth .... In general, it would seem that, 
whether the rupture of the egg-membrane takes place before or after 
the egg has left the body, the germinal mass within it, is developed 
at once into the form of the young animal, which represents that 
of its parent; no preliminary metamorphosis being gone through, 
nor any parts developed which are not to be permanent." (Principles 
of Physiology, p. 362.) 

The first male discovered, was that of Asplanchna Brightwellii, 
then a supposed species of Notommata, and is thus described by 
Mr. Brightwell. (Ann. JS'at. Hist. 1848, p. 155.) It is " about half 
the size of the female, and differs from it in form, being much 
shorter and of a rude triangular shape. It is more difficult to detect 
than the female, being exceedingly transparent, and, from the empti- 
ness of the body, appearing little more than a transparent ciliated 
bubble. It is very active, and occasionally puifs out the sides of its 
body, so as entirely to alter its form, and remains thus distended 
some time." There was no indication of any digestive apparatus, 
or of matters in course of digestion. 

" At the bottom of the body on one side, is a conspicuous round 
sperm vessel or testis, in which, under a high power, spermatozoa, 
in active vibratile motion, may be seen ; and, at its external side a 
duct, closed by distinct lateral muscles. Connected with the testis, 
is a well defined intromittent organ, and a conspicuous passage or 
opening for its extension from the body of the animal. In the 



86 GENERAL HISTORY OF 

opposite lower angle are three small, irregularis^ formed, kidney-shaped 
bodies, connected with an angular lobe or muscle IjTJig beneath them. 
The male is also fui'nished with the delicate membranous plicated 
bag, and rudiments of the curled tubular structure foimd in the 
female." 

Besides determining the dioecious character of this Rotatoria, 
Mr. Brightwell was also enabled to repeatedly verify the occurrence 
of an actual coitus occurring between the sexes, and enduring the 
greater part of a minute. 

"We append, to this account of the male, some further particulars, 
derived from Mr. Gosse's paper. On the Asj)lanchna prtodo}ifa (Ann. 
Nat. Hist. 1850.) "The principal muscles agreed with those of the 
female. The tortuous threads and their plexuses (Section XXII.) 
were represented by two thickened glandular bodies, extending from 
the head mass to the foliaceous substance suaTounding the sperm 
bag .... The three eyes were present, situated as in the female, 
but no trace of jaws was discernible, even on pressure, nor any crop, 
nor true stomach. These animals were very active, swimming 
rapidly about, and scarcely stiU an instant. On one or two occa- 
sions, I observed one of the males, with a slender process, protruded 
a considerable length from the sexual orifice, and adhering to the 
glass by its tip; moving round on it as on a pivot." 

Mr. Gosse had the good fortime to witness the development of the 
males from the ovum. He writes : "I saw the developing young in 
a pregnant female, that seemed diiferent from the ordinary embryos; 
and in hope that this might be a male, I isolated the parent; " and 
Mr. Gosse, at length, had the satisfaction of seeing two males bom 
from this female, of similar outline to the latter, but instead of being 
1-48 — 1-42 of an inch, were only 1-110 of an inch. 

Section XXV. — Of the Affinities and Classification of the Rota- 
toria. — That the Eotatorial Animalcules, by their high degree of 
organization, should be elevated in the animal scale far above the 
Polygastrica, and that they cannot be rightly comprehended with the 
latter under the general appellation of Infusoria, is now generally 
admitted, although, as hereafter stated, resemblances do exist. The 
particular affinities of the Rotatoria have not been generally agi'eed 
upon, hence, these animals have bee^ differently placed by different v 



INPtTSOBlAT, ANIMAICTTLES. 87 

authors in their proposed classifications of Invertebrata. Thua, 
Burmeistcr has classed them with Omsfacea ; Wiegmann, Milno 
Edwards, Wagner, Siebold and others, with Vermes. To which of 
these two classes of Articulata, preference is to be given, Siebold 
observes, is not verj* questionable, for their affinities, with the 
Crustacea, are but remote, since not only is there an absence of a 
distinct abdominal membrane, and of sti'iped muscular fibre in Rota' 
toria, but they present, both on their outer and inner surfaces, organs 
of respiration. Again, the Rotatoria emerge from the egg with their 
form perfect, and without any limbs in pairs ; whilst the Crustacea, 
after their bii*th, undergo metamorphoses, and are furnished with 
several pairs of extreaiiities. On the other hand, the Rotatoria 
approach the Vermes (which include the Helminthx, Turhellara, and 
Annelida) by their means of locomotion, their deficiency of limbs, 
and the lining abdominal membrane, 

Mr. Gosse, from his observations of the internal structure of 
Rotatoria, and especially owing to the presence of mandibles, maxillae^ 
and maxillary palpi, afiu'ms that they have no connexion wdth the 
Radiata. In this, he coLacides with all, or, almost, all naturalists, 
who wordd place these animals among the Articulata, though with 
which division of this class is, as we have seen, still a matter of 
dispute. 

M. Doyere at first concurred with M. Dujardin in recognizing an 
affinity so close with the Rotatoria as to class with them the Tardi- 
grada ; but his subsequent researches have induced M. Doyere to 
surrender this view, and, whilst admitting an affinity, to keep those 
two tribes of animals distinct. 

Dujardin has remarked, " The Tardigrada constitute a passage 
between the Systolides {Rotatoria) and the Jlelminthidcs on one side, 
and the Annelida and Arachnidu, on the other." 

We have before had occasion to indicate the affinity between 
Vorticellina and Rotatoria m. the wreath of cilia about the head ; as 
also to state Dujardin's objections to receiving Chlostonotus in the 
latter class ; these circumstances, consequently, prove the alliance of 
the Rotatoria and Polygastrica. In some general features, likewise, 
the two classes approach ; as, for iastance, iu the transparent sheath 
enclosing the animal of Vaginicola, analogous to that in Floscularia 



88 GENERAL HI8T0ET OF 

and Stephanoceros ; in the grouping in gelatinous masses of the indi- 
viduals of Ophrydium as compared with that of Conochilus. Again, 
in the tubular sheath of Melicerta, with its adherent foreign matter, 
a resemblance to some Annelida is manifested ; in the homy partially 
investing lorica of Noteus, Brachionus, and other Rotatoria, a like- 
ness to the Entomostraca is to be found ; and, as pointed out already, 
the long-ciliated arms of Stephanoceros find their analogy among the 
Cihohrachiate Polypes. 

In the classification of the Rotatoria, Ehrenberg was chiefly 
guided by the character of the rotary apparatus — according as it 
formed a continuous circle or wheel, when he termed it MonotrocJia, 
or was divided into two or more segments, which he named it Soro- 
trocJia. Proceeding on the same plan, he subdivided each of these 
primary divisions into two sections ; the first, into HolotrocJia and 
Schizotrocha ; the second, into PolytrocJia and Zygotroclia. (See 
Part III., class Rotatoria.) 

Siebold and others adopt this arrangement, but, at the same time, 
declare it defective and artificial. Mr. Gosse has employed it as the 
most convenient yet published, but, as we are glad to see, promises 
an arrangement more according to the organization and the natural 
affinities of its members." (Ann. Nat. Hist. v. viii. p. 197.) 

In the further distribution into families, Ehrenberg has recourse 
to the character of the surface, whether this be loricated, or illori- 
cated. But the use of these terms, after this manner, in the case of 
the Rotatoria, \& objectionable; for, as M. Dujardin remarks, "all 
the Rotatoria are clothed by a resistant integument," and hence 
" Ehrenberg is compelled, sometimes, to call a thicker and harder 
portion of the common integument, the lorica ; at other times, to 
apply the word to a diaphanous tube, or to the mucilaginous secre- 
tion enveloping in part the Lacinularia, or to the sheath of Melicerta, 
which is evidently a secretion with agglutinated foreign particles." 

In the construction of genera, Ehrenberg has been guided chiefly 
by the variations in the number and disposition of the eyes. To 
this, Dujardin also objects, for, says he, " since the eyes may dis- 
appear, from circumstances of age, or of development, the employment 
of this character, will place in different genera Rotatoria, which ai'e 
but varieties of the same species." 



INFUSORIAL ANIMALCULES. W 

Siebold adopts the genera, but not the families of Ehronberg, and 
Bujardin devises a temporaiy distribution of Rotatoria, according to 
theii- varieties of locomotion ; and, including the Tardigrada, thus 
makes fom- di^dsions : — 1 . Those which live fixed by their posterior 
extremity. 2. Those having but one mode of locomotion by means 
of their nbratiie cilia, and which are all swimmers {nageurs.) 
3. Those which have two sorts of movement, one of crawling 
{rampants) after the manner of leeches, the other of s^^'imming, like 
the preWous forms. 4. Those destitute of vibratile cilia, but provided 
with aculei or claws (ouglcs) and which are true creepers {marcheurs). 

The last di%'ision {marcheurs) has but one family viz. Tardigrada ; 
the third but one also, viz. — Rotifera ; the first two families, the 
Floscuhriens and Melicertiens ; whilst the second is separable into 
two sections, Brachioniens and Furciihn'ens, each i-epresenting nume- 
rous genera. 

Owing to the absence of silica or lime in the integument of Rota- 
toria, and its consequently perishable nature, these animals do not 
occur in a fossil state. 

The Rotatoria are distributed over every part of the world ; the 
special or Kmited geographical distribution of genera, we have, at 
present, no data to determine. 

Section XXYI. — On Shoivers of Infusorial Animalcules. — In 
ancient and modern times, storms or showei'S of solid bodies ha"\'e 
occasionally been observed. The dust which falls upon the earth, 
when of a red colour, has been compared to blood ; and in Egypt, 
where little or no rain falls, the superstitious inhabitants have been 
much alarmed when such an event has happened. Professor Ehrcnberg, 
in a work now before me, entitled Passat- Staub und Blut-Regen, 
referi'ed to at page 65, has, with the characteristic energy and per- 
severance of his countiy, investigated this subject veiy minutely, 
and I propose here, to give some of the results of his research. 

The memoir occupies 192 folio pages besides tables, and is accom- 
panied by six large plates. 

The quantity of actual solid matter that has fallen fi'om the atmo- 
sphere by showers, is far more considerable than might be imagined, 
for though it falls in a divided dust-like mass, the extent of surface 
which it covers is large. Comparing it with Meteorilites, Ehrenberg 

H 



90 GENERAL HISTORY OF 

observes, that from 1790 to 1819, there fell of the latter, stones 
whose weight amounted to 600 cwt., while in a single dust shower at 
Lyons in 1846, the material weighed full 7200 cwt. Other storms 
of dust in Italy, at Cape Verd, and other places, have even exceeded 
that at Lyons, in the amount of solid matter which fell on the earth, 
and Ehrenberg asks, how many millions of tons weight of micro- 
scopic organisms have reached the earth since the time of Homer. 
He adds, " I cannot longer doubt, that there are relations according 
to which living organisms may develope theniselves in the air." 

He supposes the atmospheric dust cloud region is of vast extent, 
and at a height of more than 14000 feet. Ehrenberg considers these 
phenomena cannot be traced to mineral substances from the earth, nor 
to revolving masses of dust material in space, nor simply to atmo- 
spherical currents, but to some general law connected with the 
earth's atmosphere, according to which, there is a self-development 
within it of li\-ing organisms. 

The following, are selected from the showers of Infusorial organ- 
isms recorded ; — 

1. In the Atlantic, latitude ll"" 43' K. and longitude 26* W. 
about 500 miles from the coast of Africa, the dust, as it fell, wa» 
eoUected by Mr. Darwin, fixim the deck of the ship. The wind at 
the time being from the coast. It resembled ashes. On examina- 
tion, one-sixth of it consisted of the silicious fresh water Infusoria 
and Phytolites — 18 species of each. Most of them were European, 
and none exclusively African. Also a South American species, 
Surirella Peruviana, and the Himantidium papilio. The inference 
formed by Ehrenberg is, that this shower came from the upjier 
regions of the air from South America, othermse those species are 
yet to be discovered in otlwi^r countries. 

2. Dust from other showers in the Atlantic were collected by the 
same naturalist, between the years 1834 and 1838. These collec- 
tions contain 30 additional forms of Infusoria, also the two species 
above named. Three of the species of Eunotia have only been met 
with in Senegambia and Guiana, also the South American AmpM- 
fiiscus obtusus. No species- peculiarly African was foimd in any of 
the dust. 

S. Dust from Malta, which fell on May 15, 1830, contained 43 



INFUSORIAL ANIMALCrLES. 91 

species of organisms, of whieli 15 were Infusorial. Some of these 
species occur in Africa, yet none peculiar to that country. This is 
remarkable, as those showers with the hot winds, which accompany 
them, are said to come from the Sahara Desert, which must be 
erroneous. Among the species were a Chili one, Synedra entomon. 

4. Sirocco dust from Genoa, May 16, 1846, contained 22 species 
of Polygastric Infusoria, 21 of Phytolitharia, and three fragments of 
plants. The colour is yellowish from oxide of iron, not grey like 
African dust, and one-sixth to one-third of its weight was organic. 
Ehrenberg remarks that these results show that the showers of dust 
from the Atlantic, Malta, and Genoa, are alike, and also exhibit an 
absence of true African forms. 

5. Sirocco dust fr'om Lyons, October 17, 1846, contains 39 species 
of Polygastrica, 25 Phytolitharia, and 3 Polythalmia. The organic 
matter forms one-eighth of the mass, and is mostly fr'om inhabitants 
of fresh water. 

Nine showers of dust from the above localities, gives in the 
whole, 57 species of Polygastrica; 46 Phytolitharia, and 8 Poly- 
thalmia. Besides 7 kinds of plants and fragments of an insect. 
Of marine species there are 17. Fresh water 102. There is no 
evidence of volcanic origin. 

6. May 16, 1846. A second shower, on the same day at Genoa, 
gave nearly the same species. 

7. Storm of red snow in Puster Valley, in the Tyrol, March 31, 
1847, contained 22 species of Infusoria and an insect, besides 30 
species of other organisms. Ehrenberg remarks the uniformity of 
character of the dust over regions so widely separate, yet in nearly 
a common latitude or zone, and in so many distinct examples 
through a number of years is most surprising. 

8. In dust which fell in Italy 1803, and in Calabria in 1813, the 
first contained 49 species, the latter 64. In both, all the species are 
of fresh water habit, and one-fourth of them similar. The most 
abundant were Eunotia amphioxys, four species of GalUonella, viz.^ 
gramdata, crenata, distans, and procera. In both also were four South 
American forms; Coscinodiscus Jiavicans from Peru and St. Domingo 5 
Navicula undosa from Sm-inam; Stauroneis linearis from Chili aa4 

s 2 



92 GENERAL HISTORY OF INFUSOETAL ANIMALCTTIE8. 

North America; Synedra entomon from Chili. The last occurs in 
Africa and Asia, but none were peculiar to Africa. 

Other facts of storms of dust are recorded by Elii-enberg. Eed 
haU was observed by Humboldt in Paramo, between Bogota and 
Papayan, at a height of 14,700 feet. 

On October 14, 1755, at LacarnQ, near Lago Maggiora. At 10 
IMfy o'clock in the morning a red mist filled the air, and at 4 o'clock in 
the afternoon there was a blood-rain, which left a red deposit cover- 
ing 40 square German miles. At the same time a reddish snow fell 
upon the Alps. It is calculated that each English square mile 
received a deposit of 2700 cubic feet. 

In 1623 blood-rain fell at Strasburgh, and in 1222 a similar event 
happened at Rome. Ehrenberg records 340 showers of blood-rain 
and dust-rain — 8 1 before Christ, commencing with the time of Moses 
in Egypt, and 259 after. (See Edin. Phil. Joui\ 1852.) 



NoTici. — The reader is refeiTcd to the appendix, for Professor 
Ehrenberg' s reply to the observations of natui-alists opposed to his 
views, of the animal natui'e of the doubtful Infusoria, 



End of Part I. 



PART II. 

OX THE COLLECTING AND PllEPARING 

INFUSOIUAL ANIMALCULES 

FOE 

Section I. — On the Method of Capturing, Selecting, and Placing 
Infusoria for Examination under the 3Iicroscope. — To procupe specimens 
of Infusoria for examination and study, no expensive apparatus is 
necessar}^, a few common wide-mouthed pliials are sufficient — those 
containing about four ounces a piece will be found most suitable — let 
them be fitted Avith proper corks, and not with glass stoppers. Some 
persons insert a piece of quil into the cork to give the creatures air. 
I have not found this necessary, but always remove the cork when I 
arrive at home. If it be requii'ed to have all the tackle neatly 
arranged, they may be put into a small tin case, expressly con- 
structed for the purpose, and each bottle separately marked. In 
place of phials, however, cylindrical glass vessels, from three to five 
inches long, may be substituted, as they will lay better in the case, 
which need not exceed the dimensions of a common sandwich-box. 
A good walking-stick, "with a hook at the end of it, and a piece of 
twine, should always foiTQ part of the equipment. As the margin 
of small ponds is sometimes difficult of near approach, I have con- 
tiived a spring-hook, which is attached to a moveable ferule, and 
made to fasten to the end of the walking-stick. Tins lays hold of 
the phial, and enables you to charge it from the surface of the 
water, in the immediate viciaity of the stalks of water-plants, a 
situation generally abounding with Infusoria. 

Various ingenious contrivances have been invented for the same 
purpose since the above was published, but, as most persons would 
be induced to adopt such a plan as would best suit themselves, it will 
be unnecessary to describe these contrivances in detail. I may only 



94 COLLECTING ANIMALCULES 

observe that those persons whom I have found the most successful in 
these matters, always employ the cheapest and simplest con- 
trivances. 

Por the larger kinds of Infusoria, and especially those Hving upon 
aquatic plants floating on the surface of the water, a small net is 
very nseful. I have for many years used one made as follows : 
Take a piece of common iron wire about 2 J feet long and |th thick, 
bend one end into a round hoop about three or four inches in 
diameter, and turn the other end into a small loop for the handle. 
Take a piece of fine Irish liaen and make it into a bag, either 
pointed at the end Hke that shown at page 51 of the "Microscopic 
Jllustrations," or roimded. This bag, when sewed on to the iron 
hoop, forms the most convenient appliance I have met with, and 
may be carried about in the coat pocket. Another appUance which 
I find of great use, is a small white saucer for the purpose of 
skimming the water. By this means, numerous kinds of Infusoria, 
which attach themselves to floating plants, may be captm^ed readily, 
}ind then transferred to a phial. 

Take with you, also, a pocket magnifier, of shallow power. This 
may be mounted in various ways ; but the one I prefer is a triple 
one, having the lenses arranged in the same plane ; the convenience 
of which is, that you will have three different powers always ready 
for use, without the necessity of moving them ; and that, the mount- 
ing being flat, it will be very suitable for the waistcoat pocket. 
Sling this, with a piece of ribbon, about the neck, and there will be 
jio danger of losing it. The magnifying powers usually selected, are 
those from flve to fifty diameters (2 inches to ^ an inch focus) ; the 
first, or largest, serving to distinguish the masses ; the intermediate, 
to show the general movements, so as to determine pretty nearly 
whether the water you have collected is worth retaining or not ; and 
the smallest, or most powerful, for examining the contents with more 
minuteness. This latter power will not so frequently be called into 
use abroad aa at home ; because, with a little practice, the middle 
&nd shallow powers will be found to answer every purpose. 

The grooved sphere (see Treatise on Optical Instruments, 1828,) 
now called the < Coddington lens,' is, when moimtcd, a very ex- 
cellent magnifier for these purposes, as in every position the rays 
traverse the axis ; but by far the best for definition, is an inverted 



FOR THE MICKOSCOPR. 95 

Huyghean eye piece of short focus, tliut is, having lenses of | and 
4 of an inch focus. 

Again a white saucer offers the best means of examining the water 
in a cursory manner, to ascertain whether the pool contains the 
animalcules you desire. 

Being equij^ped with the needful appliances — a few phials, a small 
cloth net, a white saucer, a white cambric pocket handkerchief, on 
which to place water plants to drain, and a magnifier. The sportsman 
should provide himself with a stout pair of boots, for I can assure 
him, if he enters heartily into his sport, he will sometimes find 
himself ancle dc^p in water iji beating about for choice specimens. 
Proceed to the nearest ponds of water in the neighbourhood, and 
should there be healthy Lomnse on their surface, or Conferva), or 
other aquatic plimts, you will be almost certain to meet with animal- 
cules. If there be any drains, however, communicating with them, 
the chances are that they contain only the common species, which 
will, by a little practice, be readily distinguished by their motion, 
general appearance, and colour. The indications of the presence of 
Infusoria are specks moving about in the water, or an apparent 
mouldiness around the stalks of the Lemnae, &c. Should these 
appearances not be discerned under the middle power of yoiu' 
magnifier, throw away the water, and repair- to some more favoiu'ed 
pool. Be careful to take only a small portion of the vegetable matter 
in your vessel, as its decay, and the consequent evolution of gas, 
may soon kiU all your animalcules. This must be constantly borne 
in mind. Clear pools of water, in the spring of the year, are the 
favourite places of resort for the Volvox glohator ; clear water, slowly 
running in clay or chalky soUs, for the Bacillaria and Arcellina. 
House gutters, and tubes placed to receive the rain water, often contain 
a rich supply of the Rotifer. In the winter, jom may search for ani- 
malcules in water among dead leaves, reeds, &c., which may betaken 
out, and their contents shaken off into clear water ; while the species 
which attach themselves fii-mly to these objects may be examined 
without theii" being removed fi-om them. On approaching- a pond, 
always obsei-ve the direction of the wind. On the leeward side you 
will find floating aquatic plants congregate>d, as also a scum of 
organic matter, this will furnish an abundant "take" of Infusoria; 
while, to the windward side, you may obtain clifTercut kinds and less 



96 



COLLECTING ANIMALCULES 



numerous. Dr. Ehrenberg states that lie has met with good success 
in the winter under bridges, around the piers and outworks, and 
even in frozen ditches beneath the ice. When you have filled your 
vessels, cork them carefrdly, so as to exclude the air, for the shaking 
in the caniage, when a quantity of air is left in the vessels, will 
often destroy them before you anive at your place of destination. 
In this respect, my mode of proceeding differs, from that of Dr. 
Elirenberg, who always leaves a small proportion of air in the 
vessel ; judging, therefore, from my own experience, I should con- 
clude that he is more careful than myself as to their conveyance. 
The only inconvenience I have experienced from keejiiag the vessels 
entirely filled with water, during the short time of transporting 
them home, has arisen from those creatures which appear to live on 
the surface, as Euglena, &c., attaching themselves to the cork, and 
remainiag so when required to be taken out. Remove the corks as 
soon as you get home, and place the vessels upright ; for which a 
mahogany stand, famished with a number of holes adajited for the 
vessels, will be very convenient. A gauze covering, fitted to the 
fi'amc, will keep out the dust and blacks, without obstruetirig the 
fr'ec ingress of air. 

We now proceed to the mode of investigating these minute 
creatures xuider the microscope. If the kind to be examined are 
those which swim freely, and are visible to the naked eye, as the 
Volvox, Bursaria, and other large Polygastrica, and also the free 
Rotatoria, take a sin;dl open glass tube, such as is described m the 
Microscopic Cabinet, p. 236, (edition 1832) and select 
the specimens with it in the manner there recom- ^^:iii»* 
mended. The figure of the tube I here insert fr-om "^ *^" - 
that work. The diameters of these tubes may vary 
fr-om one- eighth to one-twelfth of an inch, and their 
length fr'om four to eight inches. It may be useftd 
occasionally to di'aw out and slightly bend the ex- 
tremities which are to be immersed in the water. 

When the creatures are more minute than those 
above mentioned, pour a little water fr-om the vessel 
containing them into a watch glass, and place it upon H 
a piece of cardboard, coloured half hlach and half 
white. The white groimd will make the dark specimens apparent, 




FOR THE MICROSCOPE. 97 

and vice versd ; thus, tlie required specimens may be taken out 
singly with one of the tubes, and phiced in the aquatic live-box 
for --observation. The observer will derive much assistance in this 
operation li'om the use of the pocket-magnifier before mentioned, or 
fi*om a watchmaker's eye-glass and stand. 

When the Infusoria are extremely minute, they usiially congregate 
at the edge of the water over the white portion of the cardboard, 
and may be removed from thence with the point of a quill, or of a 
small wedgcd-shaped pencil. If a quantity of the Chara, or other 
aquatic plants, be put into a glass jar -nath the Infusoria, in the 
course of a few days, more or less depending upon the temperature 
of the season, the surface wiU be covered with a thin pellicle, formed 
by the decomposition and extrication of gas, causing the small 
detached pieces of vegetable matter to float upon the water, and 
with them the Infusoria. Let a small portion of this film be taken 
fi-om the siu-facc, by means of the feeding pin, drawn in the 
margm, and examined under the microscope, and you will 
hardly fail of being highly gratified. Among the most 
interesting genera collected fi-om the surface of these infu- 
sions, in the manner just stated, are those belonging to the 
families Vorticellina, Arcellina, and Astasicea. After the 
film has remained some days upon the water, many of the 
above-mentioned genera disappear, and are succeeded by 
those of the family Vihrionia, especially the Bacterium. 
These, however, may be easily overlooked ; for they merely 
resemble, even under a power of 250 diameters, siiitillations, 
or the vibrations of cUia, among the vegetable matter. But 
when carefully examined rmder a higher power, they will appear 
like so many small short jointed rods, each rod, or chain, having a 
distinct movement of its own. 

When it is desu'able to keep li\'ing Infusoria, it is necessary to 
examine the vessels in which they are, every day or two, to ascer- 
tain whether they contain any Entomostracea, or larvse of insects, as 
they feed upon the animalcules, and thus your choice specimens will 
be desti'oyed. From time to time, as these appear, remove them. 
It may happen that, at first, the water may not contain them, but 
only their eggs, which, in a few days, may be hatched, and the young 



COLLECTING ANIMALCULES. 



destroy all youi' Infusoria. It is also advisable to keep in the vessel 
a small (^antity of the aquatic vegetation, from among Avhich, you 
have obtained your specimens. Be careful not to have much, and 
keep it in a healthy condition. Mr. Vai'ley recommends keeping a 
small flat water snail in the water, wliich, he states, feeds upon 
confervae and keeps the water sweet. 

It is usual to give a list of places where Infusoria may be found, 
but, as some kind or other may be met with in nearly every locality, 
it is almost useless to insert one, while those ponds possessing certain 
species, in a few years change, and are no longer to be found in the 
same places. To Olustrate this, I may mention that some years ago, 
when preparing for my Natural History of Animalcules, I found the 
most prolific locality' around London, was Hampstead ; and, accord- 
ingly, in the summer of 1833, I took a cottage there, to be near the 
ponds. In some I found beautiful species of the Eiiglena and allied 
genera, in great abundance, for some years they gradually decreased, 
and last summer the same ponds I found destitute of that genus. 

The beautiful organisms known under the name of Desmidiece, 
which form one of the sections of the family Bacillaria, and repre- 
sented, magnified, in Plates II and XIII, are rarely collected in 
streams, being unattached. In clear shallow j)ools, on moors and in 
boggy places, they are generally abundant in summer. They are 
rarely found in shady woods or deep ditches. To search for them in 
turbid waters is useless. M. de Brebisson states that, in the calca- 
reous districts around him (Falaise, l^ormandy) in which the Xavi- 
culacea abound, Besmidiece are rare. In the water the filamentous 
species resemble the Zygnema, but their green colour is paler and 
more opaque. When they occui- ia large numbers, they may be 
taken up ia the hollow of the hand ; but, when diffused, Mr. Ealfs 
takes a piece of linen about the size of a pocket handkerchief, 
lays it on the ground in the form of a bag, and then, by the 
aid of a tin box, scoops up the water and strains it through 
the bag. The larger species of Euastrum, Micrasterias, Closterium, 
&c., are generally at the bottom of the pool, either spread 
out as a thin gelatinous stratum, or collected into finger-Hke 
tufts. If the finger be gently passed between them, they wiU rise 
to the smi'ace in Uttlc masses, and, with care, can be remo-ved and 



MICROSCOPES FOB INFrSOEIA. 99 

strained. At first, nothing appears on the linen except a mere stain, 
but, by repeating the operation, a considerable quantity will be 
obtained. If not very gelatinous, the Avater passes fi-ecly through 
the linen, from which the specimens can be scraped with a knife ; if 
otlierwise, the water must be poiu'ed dii-ectly into tht^ collecting 
bottle, as force would destroy them. Some species of Staurastrum, 
Pediastrum, &c., form a greenish dii-tj^ cloud upon the stems and 
leaves of aquatic plants — to collect these, requii'e much care ; the 
slightest touch will often break up and disperse them. To secui'e 
them, let the hand be passed into the water and beneath the cloud, 
the palm upwards and the fingers apart, so that the leaves or stems of 
the invested plant may lie between them, and as near the palm as 
possible ; then close the fingers, and keeping the hand in the same 
position, but concave, di'aw it cautiously towai'ds the sui-face, when, 
if the plant has been allowed to slip easily, and with an equable 
movement thi'ough the fingers, the BesmidiecB, in this way, bi-ush 
off, and will be found hdng in the palm. The greatest difficult)^ is 
in withdra^-ing the hand from the surface of the water, and, probably, 
but little will be retained at fii'st ; practice, however, will soon render 
the operation easy and su.ccessful. 

The reproductive bodies, or Sporangia of Besmidiece, are collected 
more frequently by the last than the preceding methods. When your 
bottles are carried home, they will, apparently, contain only foul water, 
but, if it remain undistiu'bed for a few hours, the Desmidiece will sink 
to the bottom, and most of the water may then be poui-ed off. If a 
little fresh water be added occasionally to replace that which has been 
drawn off, and the bottle be exposed to the light of the sun, the 
Desmidiece will remain unaltered for a long time. Mr. Ralfs mentions 
he has, in this way, kept specimens of Euastrum insigne in good 
order for five months. (Abridged from Mr. Kalfs' introduction to 
British Desmidiea?, p. 37.) 

Special instructions where necessary for collecting certain families 
of Infusoria, -will be found in the general remarks prefixed to them 
in Part III. 

Section II. — On Microscopes for Examinining Infusoria. — A good 
microscope cannot be fully appreciated imtil it is brought to the 
examination of HAing Infusoria. It is true, that we may make use 



loo MTCKOSCOPES FOR 

of the scales of insects uud otlier similar objects as teds — nay, even 
certain shells of BaciUaria, the most difficult of test objects (Plates 
XIX, XX.) — we may see with wonder the different markings on the 
siu'face of these dust-like atoms, but our admii-ation will be carried 
still higher, by the development of those brilliant coloui's and delicate 
tints which are discoverable in many sj)ecies of the minute Infusoria. 
The criterion of a good microscope, then, will be, that not only the 
fonns of these little creatiu-es, their curious structures, organization, 
and digestive apparatus, are exhibited with perfect clearness, but that 
there is also shown the deep and brilliant colouring of their visual 
organs, and the delicate tints of their variable, reti'actile, and loco- 
motive processes. 

The various methods of managing the microscope, and the different 
apparatus subsidiary to it, have been so fiiUy expatiated upon by the 
late Dr. Goring, my much esteemed colleague, and myself, in our 
joint works, Microscopic Illustrations, Microscopic Cabinet, Micro- 
graphia, 8fc., that it will only be necessary here to notice, briefly, a 
few particulars, wliich more especially relate to the subject before 
us, and to refer the reader to those works for fui'ther infonnation. 
As the expense of instruments, in the commencement of oiu' studies, 
is often an important consideration, a few words on this head maj- not 
he considered inappropriate, on this occasion. Dr. Ehi-cnberg infonns 
us, that he began his observations with a common microscope, and, 
although by his superior talent and imwearicd laboiu", he ^vas enabled 
to make some important discoveries, yet he delayed, for some years, 
the publication of them, imtil he could verify them with better 
instruments. 

At the period when our fii-st publication was announced (1827) an 
interest in microscopic science had to be created, to which I may add, 
that the achi-omatic microscope was then in its infancy. Dr. Goring 
having only a short time previous (1824) discovered the conditions on 
which their efficacy depended, namely, large angular aperture free from 
aberration. That publication aroused the attention of sjieutilic men 
to the subject, but instruments, even such as those then made, were 
veiy difficult to procui-e. To obviate this difficulty. Dr. Goiing and 
myself determined on presenting the public with detailed methods of 
constructing and testing achi'omatic microscopes. I fui'ther dii'ccted 



lKfU90niAl ANIMALCt?T,Bg. 101 

the attention of my workmen to the suhjcct, and gave them, fi'om 
time to time, such iiiibnnation, as, with tlieir skill and perseverance, 
might advance them in tliis branch of art, and I believe, up to the 
present time, the only successful artists in this coimtry are those who 
have been in my employ. 

In cases where an achi'omatic microscope camiot be prociired, 
recourse should be had to single lenses or doublets, for the ordinary 
compound, however well constructed, cannot be depended upon. 

With respect to the cost of an effective microscope, with a mode- 
rate equipment of apparatus, such for example as the one described 
in the 6th chapter of the Microscopic Illustrations, with its recent 
improvements, the price would now be from 20 to 50 guineas. Aft 
there are a great many persons who require only a plain, soimd 
instrument, of more moderate cost, I have deemed it expedient to 
take this also into consideration, and, after much application and 
repeated experiments, have at length produced one, in eveiy way 
suitable to the case. Such is my "miniature aclrromatic microscope.' 
It may be stated that nine-tenths of the observations recorded in thia 
work may be repeated and tested by this microscope. On comparing 
the above instruments with that used by Elu'enberg, there is no doubt 
that, in point of mechanical eonsti'uction, they are greatly superior, 
whilst the optical part is equal to any ■n'ith wliich his researches have 
been made. 

My experience induces me to recommend to all who wish to study 
this subject, two microscopes — the one a small vertical one with a 
little achi-omatic body. The construction which I prefer, is similar 
to that drawn and described in the Microscojjic Cabinet, page 243, 
The stage is cuxailar and the body is about four inches long, it is 
usually known as the "Miniatiu'e Aclu'omatic Microscope," its piece,, 
with an object glass of one-seventh of an inch focus, is five guineas. 
This instrument I find preferable, in the first examination of an 
object, to a larger and more expensive microscope, while in travelling, 
its portability is a strong recommendation. Its defects are, that you 
cannot use a low magnifier with the achromatic body, but this is of 
little moment, as a few single or doublet magnifiers will always com- 
pensate for it. As many persons may think such an instrument a 
mere toy, I can assiu'e them, that with the addition of a powerful 



102 MICROSCOPES FOR 

object-glass, and placing the miiTor on one side so as to obtain obliqtte 
light, I have seen, on a clear day, and without any trouble or any 
complex apparatus, most of the diflBcult lines and dots on the shells 
of the Navicula, such as those represented in Plates XIX and XX. 

I am fully aware that a microscope may be too small for real work, 
but the opposite extreme, too often exists now, and where an obserrer 
can have recourse to two microscopes, he will always find it pre- 
ferable to making one do all the work. 

Whether the examination of Infusoria be for the purpose of amuse- 
ment or investigation, the proper illumination of them is of much 
importance ; in the first place, improper illumination not only pre- 
vents an agreeable view to be obtained, but greatly fatigues and 
injures the eye ; while, for the investigation of the true structure of 
an organism, the proper illumination is of vast moment. The different 
methods of illimiinations may be enumerated as foRows : 1st. Direct 
light — either simple, or condensed and unrestricted, or restricted by 
diaphragms or stops. 2nd. Ohliqtie illumination — either simple or 
condensed. 3rd. Hie hlach ground iVumination. 

Black groimd illumination. The original account of this plan wiU 
be foimd in the Micrographia published in 1834. Since then it has 
been variously adapted. The simplest plan is to place the mirror out 
of the axis, and to direct the Hght from the min-or so as to illumi- 
nate the field of view, and by gently turning it (while looking 
through the microscope) until the object only is bright. In this 
simple way many animalcules are seen to advantage. I have before 
me some specimens of the Volvox glolator, prepared in 1841, which 
are sho^vn in this way to great advantage. 

The muscular fibres of the Rotatoria, and the markings on the 
lorica of the Bacillaria, &c., are brought out in a most remarkable 
manner by this mode of illumination. For an accoimt of the method 
of examining objects in this way, see the Kev. Mr. Eeade's paper in 
the Micrographia. 

Some obsen-ers disapprove of the use of candle or lamp light, on 
accoimt of its colour, and consider clear day Hght can alone show an 
object properly. As, however, artificial hght is sometimes imavoid' 
able, it has been proposed to obtain white light, by passing the yellow 
rays from a candle through blue glass, or such media as "will 



INFrSORT.VL ANIMALCrLES. 103 

neuti-alize the yellow. To obtain the correct tint of blue for this 
pui'pose, it has been proposed to select a crystal, which, by polarized 
light, gave the exact yellow tint of the candle, and then, by turning 
the polarizer a quarter round, you have the crystal of the exact blue 
required. 

This method of sifting the light, leaves for use only so much from 
the candle as is imperfectly monochromatic, which, I am inclined to 
think, is too feeble. Obscrvci-s should bear in mind the results of 
the observations in the Microscopic Ilhistrations, on this subject, 
namely, that a piu'c intense light is far more important than quantity. 
In viewing live animalcides, it will be well to be provided with 
diaphi'agms or stops to place imder yoiu" object. By the employ- 
ment of these, you ^oll the more readily be able to detect cilia, alsa 
their an'angement and the civrrents in the water produced by cilia. 
In viewing the striae on the lorica of the BaciUaria, stops or diaphragms 
must not be used. In general, oblique light is best to demonstrate 
their existence. When Dr. Goring and myself were fii'st engaged 
upon test objects, it was laid down by us as an axiom, that all lined 
objects required oblique light. Subsequent improvements made in 
consequence of our pointing out the value of angidar apertui'e- 
(imknown until Dr. Goring discovered it) enabled microscopic ob- 
servers to see the lined tests of those days with direct light. This- 
induced some observers to deride the idea that oblique light was- 
at all necessary. The recent discovery of more difficult tests, viz., 
the minute shells of certain Kaviculfs, has shown that, even with our 
most improved achromatic microscopes, it is necessary, nay, so 
ticklish a thing is the illumination, that I am informed that those- 
who make the structui'e of these shells a special study, require 40 or 
50 minutes manipulation ■with a first rate instniment, and all the 
modei'n ingenious appliances for obtaining intense oblique light, before 
they can show certain stria; or dots on a well-known specimen. 

While treating of oblique illumination, I may mention that, if 
artists can produce object-glasses of increased angular aperture, it is 
probable we may commence another cycle in om* modes of observa- 
tion, and then view all the present difficult tests with centi'al light. 
Mr. Johnson, of New York, states that such has been done by Mr. 
Spencer, who has produced an object glass of one-twelfth of an inch 
focils and 147° of clear aperture. However, so long as oblique light 



I0:t MICKOSCOPF.S FOB 

is neoessar}*, I Trould recommend obseiTcrs, when requiring it of great 
intensity, to employ reflection for condensation, and not obtain their 
condensation by refraction. On this account I prefer the ingenious 
paraboKc reflector of Mr. "Wenham (see Micrograplm, p. 88. fig. 8)^ 
or the same in solid glass as contrived by ls\x. Shadbold. The beautiful 
oblique prism of M. Natchet, has many useful properties, still on 
principle all condensation by refraction should be avoided. "When 
the construction of the microscope will admit of a "wax taper to 
be placed close behind the object, which those described in the 
" Microscopic Illustrations" do, very pure vision is obtained. 

Another point of some imj)ortancc in the examination and verifica- 
tion of striated objects is the power of making them revolve in the 
axis of the optical part of the microscope. This is efi'ected both in 
Dr. Gorings Engiscope and in mine. To obtain this pm'pose, it is 
necessary that the moveable stage be attached to a fix;ed ring, so that 
the motions, however eccentric they may place the slides, shall 
always keej) the object in the centre of revolution. 

For viewing animalcules in phials or glass tubes, there is no method 
so good as that of placing the phial itself in the spiiag pliial holder, 
having fii'st tiuTied the microscope on its side, as shown in the 
Micromopie inustrations, figure 21. A microscope that has not the 
necessaiy motion for this purpose, cannot do its work effectually, 
therefore all large instruments should possess it. 

In a large microscope, which is a great luxury always to have at 
hand, I find it ad\T.sable to have it eqmpped with two ackromatic 
bodies — a large body for shallow magnifying powers, and a small one 
for high powers. 

The magnifying powers of a complete microscope for perfectly 
examining all kinds of Infusoria should range fi'om 50 to 1000 
diameters; and as this cannot be obtained with first-rate glasses, 
without rccoiu'se being had to several sets, such an instrument would 
be necessarily expensive. The microscope first mentioned has two or 
thi'ee sets of glasses, varpng fi'om 35 to 800 ; and the second, one 
set, from 100 to 250 diameters ; so that, as before stated, all the 
most intei'csting observations on Infusoria may be conducted with 
either of these iusti-uments, whilst additional sets may be obtained 
as occasion requu'cs. 

It is important to notice, that in all cases where the magnifying 



TN^rrRORIAT. ANIMALrtTLES. 



105 



powers of microscopes are spoken of, the standard of siglit used in 
computing them should be Imo-mi, otherwise veiy eri'oneous ideas will 
be formed. In all my publications, fi-om 1827 up to the present time, 
reference has been had to a ten inch standard, and the enumeration of 
powers has been in diameters, or what are sometimes termed linear ; 
thus, what I compute at 100 is often spoken of as 10,000, that being 
the superficial measurement , ample reasons for the adoption of linear 
measure, and of that standard, are given in my works on this 
subject. 

In demonsti-ating minute portions of the structiu'es of Infusoria, a 
power of 800 diameters will sometimes be requisite, unless the sight 
be exceedingly good. I have invariably observed that aged persons 
require greater assistance, in this respect, than young ones. Not- 
withstanding this, it will be impossible to anive at an accurate 
knowledge of the creature you may be studying, even mth a power 
of 800, unless it has been previously examined under a lower one, so 
that the relations of its several parts may be first clearly understood. 
"Whenever the object in view is merely that of instructive amusement, 
a power of 250 diameters will be amply sufficient ; that power can be 
managed with ease, and does not fatigue the observer. The greater 
number of Ehrenberg's discoveries were effected under a power of 380. 
I am not aware whether he has mentioned in any of his works the 
sidereal focal length of his object-glasses, or the standard of sight. 
The set which Dr. E. speaks most in praise of is similar to one which 
I employ, and which has a focus of l-7th of an inch. He considers 
that with " a good achromatic microscope and a lamp, our observa- 
tions maybe carried on at night as well as in the day, which, by some, 
may be esteemed an additional recommendation." (For further in- 
fonnation on the illumination of Infusoria, see Part III, Bacillaria.) 
Section III. — On Micrometers, and the Method of Measuring In- 
fusoria. — The late Dr. Goring, in the Microgra/phia, has described the 
method by which, in various ways, a correct admeasurement may be 
taken of these minute creatui-es, as also Mr. Bauer, in a paper in the 
same publication. I cannot do better than refer the reader to these 
authorities, for the fullest infonnation attainable on this subject. A 
few words, however, may be said on the mode of proceeding, which 
I have myself adopted, and which, after much practice, has been 



106 MTCKOSCOPES FOE 

productive of very aeciu'ate results. It is as follows : — Having set 
up the microscope and screwed in or adapted the glasses which are 
intended to be used, take a glass micrometer, and place it on the 
stage in the same manner as if it were an object to be viewed, then 
carefully adjust the focus of your instrument, so that the lines on the 
micrometer may appear quite sharp and distinct. Next, take a 
common ruler, or a slip of cai'd-board with equal divisions of some 
known measurement drawn upon it, every tenth division being longer 
than the rest, and fix it 20 inches from the eye, whilst looking through 
the microscope ; then, whilst one eye is directed to the rule or cai-d- 
board, and the other to the lines of the micrometer, seen in the 
microscope, ascertain how many on the card are equal to a given 
number on the micrometer. If the divisions on the latter be 1 -100th 
of an inch, and one of them be equal to ten on the card, it is clear 
that every division on the card will represent 1-lOOOth of an inch. 
Thus, when the micrometer shall be removed, and an animalcule be 
put into its place, if the creature subtend five divisions on the card, 
its size in linear measure will be 5-lOOOth of an inch. Note — The 
glasses must not be changed diuing the cxpeiiment, nor their dis- 
tances apart ; neither must the distance between the card and the 
eye be in any way altered. 

Sectiox IV. — On Glass Tiibes, ^c, for iahing Infusoria from the 
Water, and placing them in the Apparatus for examination. — As these 
useful little contrivances, (which have been before alluded to in page 
96) are drawn and described by me in the Microscopic Caiinet in 
1832, it wiU be necessary merely to mention that little or no im- 
provement has been made uj)on them since that period, excepting 
perhaps that a, finer description is found to answer the purpose better 
than when the larger ones are drawn out at their extremities in the 
manner there proposed. The reader will find figui-es and descrip- 
tions of several useful little contrivances in a work entitled 
'■'■Microscopic Objects — animal, vegetalle, and mineral.'" 

Section" V. — On the Compressor, or Crush Box. — The last i-emark 
is equally applicable to the Aquatic-live-boxes, which were described 
in the Illustrations, 1828, and subsequently their different modifica- 
tions. In order to form an idea of a compressor, or crush-box, you 
must sujiposc that the cover of the live-box is so adapted to its box 



INFtrsORIAL ANTMALCUtES, 107 

by a screw, or some other convenient means, as that a small body 
placed \mder it may receive a certain degree of pressure without its 
parts being dislocated. In my original live-boxes, this was effected 
by a screw being attached to the cover ; but, in the ordinary way, 
the cover is made to revolve. In some, I have substituted a guide- 
piece for the screw, so that the pressure is obtained without the glass- 
plates sliding one upon the other. The German opticians attach the 
cover or upper plate to a jointed lever, at the longest end of which 
a screw is applied, which brings the upper plate connected with the 
short-arm, in contact with the lower plate. The use of the cnish- 
box is to protrude certain parts of the animalcule for examination by 
pressing do^vn upon the creature. In tliis manner, the teeth of the 
Rotatoria become distinct. Other uses of this apparatus are given 
when speaking of the muiute loricated Pohjgastrka. 

I have lately employed with very great advantage, in place of the 
Aquatic Uve-box, an apparatus which is peculiarly siiited for viewing 
living Infusoria. It combines the use of a live-box and compressor, 
and may not inappropriately be called a7i Aquatic plate. It is com- 
posed of a stout plate of glass, the size of a common slide. Over 
this, is a moveable plate of brass, with a spring fixed to it, and a thin 
disc of glass in the centi'e, to cover the object. The two plates are 
connected by two screws — one to hold them together, the other for 
adjustment of distance. I am indebted to Mr. Wenham for the 
original idea which I^have improved upon. 

Section VI. — On Vieiviyig Infusoria hj Polarised Light. — Having, 
in the last edition of the Microscopic Illustrations, given a full 
description of the Polarising Microscope, and the apparatus necessary 
for using any microscope for polarising purposes, a very few remarks 
on the effects produced by viewing Infusoria under this light will be 
sufficient here. 

The sihceous covering of Infusoria is but slightly affected by 
polarised light : that the effect is ojily feeble, is attributable to the 
extreme tenuity of their shells, for could we but contrive the means 
of magnifjong the effect, I feel convinced that some very important 
results would be obtained. The ribs or striae on the Navicula, assume 
a slight tinge of colouring when the polariser and analyser are 
parallel to each other ; but when they are crossed, owing to the few 

I 2 



108 MICKOSCOPES FOK 

rays whicli are transmitted, I •\^'as unable to perceive it. Isthnia are 
elightly iniluenced by polarised light. The larger Infusoria I have 
not examined, nor am I aware that any infonnation is recorded on 
this subject. 

Section VII. — On the Method of Feeding Infusoria with Coloured 
Sulstances. — Select for this purpose such coloured substances as are 
entu-ely fi'ee from metallic oxides, and not chemically soluble in 
water. They must, however, be capable of a veiy minute mechanical 
division. The substances generally used are cannine, indigo, and 
sap-green, the &st being preferable. This material should be as 
piu'e as possible. Take a piece or cake of it, and rub the corner 
once or twice on the stage-glass, or what perhaps is better, the lower 
plate of an aquatic live-box, having first moistened it -svith a drop of 
water. The coloiu' requisite for the purpose is very small — only just 
suiScient to render it ajjpreciable to the naked eye — for if there be 
too much, the probability is, that the particles will be too large for 
the creatures to imbibe. Having thus prepared the coloured food, 
place a di'op of it beside a drop of the water containing the animal- 
cules, but not so that they may come into contact ; then put on gently 
the cover of the live-box, and lower it sufiiciently to flatten the two 
drops of fluid, but not to force them to unite. Now place the live- 
box under the microscope, and examine the animalcules as closely as 
you can, and especially so as to ascertain that then- stomachs ai'e 
coloui-less ; then press down the cover imtil the di-ops of fluid inter- 
mix, which may be done under the microscope, and you wt.!! immedi- 
ately perceive the creatiu'es ia great activity, and readilj- distinguish 
the ciha and i)roboscides of those which possess them, while in a few 
seconds their stomachs will be filled with the coloured substance. 
Some animalcules, however, take a considerable time to efi^ect this, 
but such is an exception to the general rule. 

Section VIII. — On the Mode of Drying and Preserving Infusoria. 
— Although such exceedingly small creatures as animalcules, when 
dead, lose many of their- characteristic leatiu'es, especially the soft- 
bodied ones, yet, for the verification of some parts of their structure, 
such as the mandicatory organs, muscular system, and visual points, 
it is absolutely necessary to obsei-ve them in a quiescent state ; and 
hence, a method of efi'cctuaUy di-ying and preserving them must be 



INFTTSORTAL ANIMAT.CItLKS. 109 

considered esseiitial. Txu-Hhria, in this condition, have often been 
preserved by botanists, in collections of minute Alg'a3, and with very 
little management ; but other families will require more care. 
Having selected the creature you wish to preserve, remove it with a 
fine pointed quill, and put it on a slip of glass, or other convenient 
receptacle. By this means there will be but a small portion of water 
surrounding it, which may be removed by some pointed pieces of 
ragged blotting paper. When you have withdraviTi as much of the 
water as possible from the specimen, the remaining moisture may be 
readily e^'aporated, by placing the glass on the palm of the hand. 
The Hydatinea may be best presei'ved when destroyed with strychnia, 
and then rapidly dried. By what mode soever life may be taken 
away, it is absolutely expedient that they should be speedily and 
cai-efiilly dried, otherwise their bodies will be decomposed, gases 
evolved, and the object will fail. 

I have seen a fine collection of dried specimens of Rotatoria, pre- 
served by Ehrenberg between small discs of mica. These are very 
portable and may be carried about in a pocket book. Each specimen 
worthy of observation, had a ling of paper gummed to the mica. The 
discs of mica were about three-eights of an inch in diameter. Several 
of these discs were arranged in a row, and attached to a slip of mica 
three inches long and one-eighth of an inch wide. 

Another way of mounting for the microscope dried Infusoria, is on 
slips of plate glass, having a polished circular cavity, in which to 
deposit the creatures. These may be numbered, or otherwise marked, 
with a writing diamond, and a large collection of them arranged in a 
very compact case. 

Possil Infusoria are best preserved in Canada balsam, under thin 
slips of glass. (See Section X.) 

Infusoria, when simply dried, may be relaxed again by moisture, 
and some of them will bear this o]ieration several times — the soft- 
boflicd ones, however, only once. The general colour of Infusoria is 
retained for a considerable time after they have been dried, but the 
pigment of the eye is soon lost. It may be Avell to obsei've, that 
when the preserved specimens are intended to illustrate the nutritive 
system, they should be previously fed with coloming matter ; but for 
observation on other organs, this is not advisable. 



110 MICEOSCOPES FOE 

Section IX. — On Infusoria contained in Flints and Semi- Opals. — 
It is hardly possible to take up and examine a dozen flints without 
discoveiing species of Infosoria inclosed within them. These may 
be best seen imder the microscope, when very thin sections are made, 
like those of fossil woods, teeth, coal, &c. : when these are polished 
and cemented on glass slides, they form permanent objects. Small 
splinters of flint, broken ofi", may be used for investigation by the 
microscope, but such experiments are attended with veiy consider- 
able danger to the object-glass of the instrument, by its being brought 
accidentally into contact with their sharp edges, which oftentimes 
cut and injure it without your being immediately aware of the fact. 

Section X. — To prepare Fossil Infusoria for the Microscope. — 
Among various earths, marls, and chalk, will often be found the 
siHceous shells of Bacillaria. Sometimes the whole mass consists of 
them ; in the latter case it will be sufficient to place upon the slides 
a little of the powder, add a drop of water, and cover it with a thin 
plate of glass when your object is ready for the microscope. This, 
however, will be only a temporary preparation. "When requii'ed to 
be permanent, Canada balsam, varnish, or gum, must be substituted 
for the water. By far the majority of specimens of shells of In- 
fusoria are met with among foreign matters, from which it is neces- 
eary to separate them as in the case of Guano, &c. 

"When the earth can be separated by washing in water, this plan 
may be adopted. In some cases it requires boiling in nitric acid, 
which dissolves the foreign matter and allows the shells to be sepa- 
rated. In this way some care is required, otherwise the shells will 
burst asunder, and you will only obtain fragments. Another objec- 
tion to the use of acids, is that the shells will attract moisture when 
required to be mounted dry. 

Another method of separating Fossil Infusoria fi'om the earths, is 
similar to that employed by D'Orbigny in separating the beautiful mi- 
croscopic shells of the Foraminifera, and has been successfully adopted 
by Professor Bailey of New York, in detecting the shells of Bacillaria 
in sedimentary deposits. It is as follows : Take the sediment or 
earth in which Infusiora are supposed to exist, and gradually, 
but completely dry it ; then take a glass full of cold water and 
strew the powder upon the siuface of the water, when in a few 



INFUSORIAL ANIMAT.CITLES. Ill 

niinutes the earth and sand will sink to the bottom of the glass, and 
the shells being filled with uir, will float upon the surlace, and may 
be removed b)^ gently introducing a slip of glass under them. 

Section XI. — On moimtiuci Infmoria permanently in fluids. — By far 
the greater number of Infusoria are entii'cly destroyed when dried, 
some, however, of the larger kinds, may be preserved in gum water, 
which, when diy and indm^ated, wiU last a long time, if kept from 
mildew. Canada balsam will preserve some few, but tliis latter plan 
is specially applicable to the loricated class. 

In moimting objects in Canada balsam, it is requisite to have it, 
as also yoiu' glass slides, kept warm. The slide, vnih. objects on it, 
shoidd be held over a small flame, and a di'op of the balsam allowed 
to fall upon it. Wlien this is sufficiently heated, the whole should 
be covered with a thin plate of glass, and placed in a warm situation 
until it becomes hard. 

As many organisms cannot be preserved in gum or balsam, and 
alter and change theii- forms when diy, it becomes essential to theii- 
due preservation to mount them (as it is technically termed,) in a 
fluid. To effect this piu-pose effectively, two particulars are ne- 
cessary to be observed — fu'st, the selection of the fluid ; and second, 
the mechanical contrivance for permanently enclosing it with the 
specimen. 

The requisite qualities in a preser\'ing fluid are — fb'st, that its 
refractive power shall be such that it wiU permit the outline or 
boundary of the specimen to be distinctly seen. This cannot be, if 
its refractive index is the same as the object enclosed. When the 
object is surrounded by a mucus-like envelope, this consideration is 
important. Second, that it wiU not change the colour of the speci- 
men, or decompose any of its delicate parts. In the Bacillaria, the 
green matter, called by botanists endochrome, and which is so beau- 
tiful a character in the Besmidiem, is soon injured by corrosive fluids. 
Third, the fluid must not facilitate or permit the growth of minute 
fungi, or the development of any organic filaments, as the germs or 
spores of these minute beings are almost eveiywhere present, and, 
indeed, it is hopeless to procure specimens free from them. 

The iii'st two conditions are best complied with by the use of dis- 



112 MICEOSCOI'ES FOR 

tilled water, but tLe tlikd is fatal to its employment in a pui'e state, 
hence various formulae have been proposed, of which the following 
are the chief : — 1. Biine, that is, a solution of common salt in water. 
2. Alum dissolved in water. 3. Corrosive subhmate (bichloratc of 
merciu-y) in water. 4. Sulphate of the peroxide of hon dissolved in 
water. 5. Sulphate of zinc dissolved in water. 6. Sal ammoniac 
(hydi'ochlorate of ammonia) in water. One or other of these solu- 
tions are recommended by different naturaHsts, while those who 
recommend the same, differ, in the degi-ee of concentration necessary. 
In all cases it is advisable to use distilled water, and to filter the 
solution tlu'ough bibious paper. 

Aqueous compound solutions are also employed, but these vaiy 
greatly. 1 . Dr. Goadby used the following as a preserving fluid, 
and has had great experience : bay salt 4 oz. ; alimi 2 oz. ; corrosive 
sublimate 4 grains ; and boiling water 2 quarts. These are to be well 
mixed and filtered. 2. Bay salt 3| lbs. ; con-osive sublimate 7 grains ; 
and water 6 quarts. 3. Arseuious acid 2 di'achms; bay salt 3 lbs. ; 
and water 6 quarts. 4. Another fluid is composed of alum 3 parts ; 
common salt 1 part, and water 24 parts. 

Alcohol, creosote, chromic acid, sugar, and glycerine, have each 
been employed as preserving fluids. The fii'st two require large 
additions of water to prevent them from corrugating the specimens. 
Thus five parts of water is used with one of alcohol. Mr. Thwaite"s 
fluid, which is very excellent, is composed as folloAvs : distdled water 
16 parts, rectified spuits of mne 1 part, saturated with a few drops 
of creosote. To this mixtiu-e he adds a little prepared chalk, filters, 
end adds an equal mcasm'e of camphor water. 

In some cases Canada balsam mixed Avith castor oil has been used, 
while gum water, when slowly diied with the specimens, and after- 
wards surroimded by a varnish, often answers very well. 

The mechanical contrivances for secui-iug the specimens and fluid, 
are as various as the fluids. 

The size of the glass shdcs should be miiform, the usual length 
generally adopted, is that given ia my little work entitled a List of 
2000 Microscopic Objects, namely, tluee inches : the width will vtuy 
to suit the prepaiations, but one inch is that most usual. Having 



INFtrSOEIAl ANIMALCULES. 113 

procured a munber of these glass slides, which may have their edges 
ground and polished. Procure some thin glass either in slips or discs 
for covers. 

Next provide yourself with suitable cement or thick varnish to 
connect the two. Some preparers use the painters white lead to form 
a shallow cell, which holds the specimen with a drop of preservation 
fluid. Others use " gold size," which they thicken with lamp black, 
or litherage. When deeper cells are required, but which are rare for 
Infusoria, thin slices of glass tube, or rings of gutta percha, cemented 
to the shdes with Canada balsam, or varnish are used. In any case 
the operator will, by the use of his judgment, and a little ex- 
perience, soon find a method to suit his piu-pose. It is, therefore, un- 
necessary to enter into minutise. The desirata is a substance which, 
when indurated, is sti'ong and not brittle, and second, the filling the 
cell so that no air be left in it. 

In all cases where Canada balsam, or any other substance that 
indurates can be xiscd forpresenong objects, cells of fi.uid should not 
be employed. That tliis remark is connect, may be infeiTed from the 
very general use of Canada balsam, a substance which I Gist pro- 
posed for that pui^jose, and gave to the public after many previous 
ti'ials with giun and varnishes. 

For fiu'ther particulars on this subject, see " Microscopic Cabinet" 
and "Microscopic Objects." 

Section XII. — To mount Infusoria as Ojmque Bodies. — Tliis method 
of mounting appHes principally to the siliceous shells of the Bacillaria. 
It consists of fixing by gum or vamish, to a black disc or cylinder, 
the specimens to be examined. '^VTiere this plan can be adopted, it 
is always desu-able, as it affords a more con-ect \'iew of the structui-e 
of the siu-face, indeed it is the best verification that can be obtained. 
In some cases fragments of the earths containing Navicidce, Campih- 
disca, &c., may be mounted without separation ; in other cases, the 
shells may be separated by solution of the lime and foreign matter, 
and only the washed shells mounted. 



P A E T III. 



classificatiojst and description 



INFUSORIAL ANIMALCULES. 



Class I. POLYGASTRICA. 



Note. — The Abbreviations used herein, are explained at the end of the 
Contents. 



This class of animalcules is denominated Polygasti'ic from possessing 
a digestive apparatus composed of many globular vesicles, which 
perform the functions of stomachs. They have no perceptible nervous 
cords or pulsation. They are hermaphi-odite, and increase by self- 
division, or by the growth of genimulcs, or of little buds, xipon their 
bodies ; hence their external foims appear to vary. Their locomo- 
tive organs consist of processes (often vibratory), but they are 
destitute of true articulated feet. 

The Polygastric animalcules, according to Ehrenberg, comprehend 
the following families, whose relations to each other may be seen in 
the table on the next i)age. 



116 



RELATIONS OF THE POLYGASTRICA 



f self-division f 'llo^icated or shell-less Mouadina 
complete ( loHcated or shelled 



Body 

destitute 

of upiiendaires. 

(No foot-like 

jjrocesscs). 

Gymnica. 



Foot-like pro- 

cesses 

variable. 

Pieudopoda. 



Hairy 
Epitricha. 



One receiving 

and discharging 

orifice only for 

nutrition. 

Anopisthia. 

Two orifices 

one at 

each extremity'. 

JEnantiotreta. 



Form of 

body 
constant 



Oyptomonadina 
f illoricated Hydromorina. 



self-divison 
incomplete 

hence 

formed in 

clusters 



self-dividing on all 
sides (globular 



self-dividing 
unilaterally 

, (filiform) 



Volvocina. 
illoricated Vibrionia. 



. kiricated Closterlna. 



Form of r 

body < 

. variable ( 



Form of ( illoricated Astasiaea. 

loricated Diuobryina. 

' illoricated Amoebaea. 



loricated 



f compound foot-like process from one ) Aycpllina 
' aperture j Arceuina. 

simple foot-like process from one or It. •,, • 
from each aperture | aacuiaria. 

illoricated Cyclidina. 

loricated Peridinaea. 

illoricated Vorticellina. 

loricated Ophrydina. 

illoricated Enchelia. 

loricated Colepina. 



Orifices situated iHoricated 



obliquely 
Allotreta. 



Orifices 
abdominal. 
Catoireta. 



mouth furnished with proboscis, tail ) t,.„„u„,- „ 
absent ] nacneiina. 



mouth, anterior, tail present Ophryocercina. 

Lloricated Aspidiscina. 

f ( locomotive organs cilia Kolpodea. 

I illoricated ' 

various Oxytrichina. 



(.loricated Euplota. 



Pamilt— MONADINA. 

The animalcules of the family Monadina are the most minute hving 
creatures which have been discovered by man. They are destitute 
of an alimentary canal ; are illoricated or shell-less, and have an 
uniform body without any appendages issuing from it, cilia not being 
considered as such. They increase either by a simple and complete 
self-division of the body into two, four, or more individuals. The 
uniformity or unvarying appearance in their external forms may be 
considered as one of the principal characteristics of this family ; for 



3fo)iach'>in.'\ 



INFUSOEIAL ANIMALCULKS. 



117 



no 3fonndina can voluntarily alter tlio shape of its body, whether 
into a filiform, knotty, or globular figure, nor can it extend any 
portion of it, and then contract it again. It is quite evident that 
they all jjossess organs of locomotion, nutrition, and propagation, 
which latter are of the hermaphrodite character. Some of them 
have a rudimentaiy eye, but it has never been discerned that they 
are furnished with a vascular or circulating system, which, however, 
is not surprising, when we reflect that should they possess it (a sup- 
position by no means to be rejected), the diameters of the tubes of 
this system would necessarily be of such extreme minuteness as to 
defy investigation. 

The groups and figures in Plate I., numbered I to 20, convey a 
very fair idea of the appearance of the Monadina. None but mi- 
croscopes of high magnifying powers can develope theii- sti-uctures ; 
indeed, they cannot be observed accui'ately with a less amplification 
than 500 diameters, together with considerable penetration and a 
good definition. 

The family is distributed by Ehrenbcrg among nine genera, as 
follow ; — 

f single Hlonas. 

Eye wanting < 

L Aggregate Uvella. 



Swimming < 



Eye present < 



r Proboscis \ Mic-o^iena 
one or two ) Micro^iena. 



Single < 



Proboscides not i 
more than four I 



Proboscides 
many 



Chloraster. 



Phacelomonas. 



Aggregate Glenomorum. 

Rolling Doxococcus. 

Lips present Chilomonas. 

Tail present Bodo. 

Eeference to the classification proposed at (page 62), will show 
that the genera comprehended by Ehrenberg, in this family Monadina, 
as well as in Ch-yptonionadina, Volvocina and Vibrionia, are not re- 
cognized as Infusoria, by Siebold. For so extensive an exclusion of 
genera from the List of Infusoria, Siebold offers no distinct and clear 
explanation, but fi-om his remarks, we may gather that the excluded 



118 DESCRIPTION OF 

organisms are in his opinion of vegetable origin, and more especially 
embrj^onic forms, sucb as spores of various Confei"V8e, of Vaucberia, 
&c. That eminent comparative anatomist states, (Anatomie der 
Wirbellosen Thiere, Book 1st., p. 8. Berlin, 1848), that "ciliated 
organs occur in the vegetable kingdom, in the form of ciliated 
epithelium in the spores of Vaucberia, and in the shape of long 
filiform isolated fibres, in the spores and early stages of existence of 
several species of Confervae ; many of which organisms indeed, 
Ehrenberg has described as belonging to the families Monadina, 
Vohocina, «S:c." 

The active movements of the Vohocina are identified with those of 
plants, and, to Siebold's mind, distinguished from those of true animal 
Infusoria, such as the Kolpoda, by entirely wanting a voluntaiy 
character. 

Another distinction, separating such genera ft'om the animal 
series, the same naturaKst finds in the unalterability or fijdty of 
their general outline, all animals having the power of varpng their 
outline, by the contraction or expansion of their substance. 

M. Dujardin, although admitting generally the animal nature of 
the families in question, differs very materially from Ehrenberg, in 
his views respecting their organization. 

The third order in the classification of this naturalist which in- 
cludes the Monadina, Vohocina, Dinohryina, TJiecamonadina, Euglena 
and Peridinia, has for its common characteristic the existence of one 
or of several flagelliform filaments, serving as locomotive organs. But, 
Dujar din's definition of the family of Monads difi'ers widely fi'om 
that of Professor Ehrenberg, in assigning no mouth or digestive sacs, 
and in attributing to them a form generally variable, and a capa- 
bility of contracting adhesions to one another, owing to their soft 
gelatinous bodies being unprotected by any epidermis. Dujardin, 
moreover, cannot admit the red specks to be eyes. 

The apparent sacs he terms vacuoles (vacuolse), and considers 
them to be spontaneously hollowed out in the body of the animal, 
and when, as usual, near the surface, to open externally, and on again 
contracting, to enclose any foreign particles which may have intro- 
duced themselves. According to the French micrographer, therefore, the 
Monadina are nourished only by absorption, effected by their external 
surface, and, in some measure, by the spontaneously formed vacuolae. 



INFUSORIAL ANIMALCULES. 



119 



Diijardin also states that lie has been unable to recognize all the 
genera of Ehrenberg, and believes that the Microglena, Phacelomonas, 
Glenom(yrum and Doxococcus appertain to another family, that the 
distinction between the genera Polytoma and Uvella, is erroneously 
deduced from the supposed fission of Polytoma in two opposite di- 
rections, and the periodical grouping of JJvella. He thus reduces 
the genera of Ehrenberg, to four in number, viz Manas, Ifvella, 
Chilomonas and Bodo, the last comprehending in part his Sexamita, 
Am2)himonas, and Cercomonas. The subjoined table represents the 
distribution by Dujardin, of the 



MO^^ADINA. 



f Moveable in its entire 



A Single 

Flagclliform •< 

Filaraeut. 



Proceeding from the anterior I ^l^"^"! Monas. 



Isolated 



Aggregate 



„„» ;,„ ^ Thickened, and move- 

'^^^'^^"'y- ] able only toward.s 

L the e.xtremity Cyclidium. 

Proceeding: obliquely from behind an anterior pro- 
longation Chilomonas, 

' A second filament or lateral appendage Amphimonas. 

A second filament, or posterior appendage Cercomonas. 

Two equal filaments, terminating the rounded angles 

of the anterior extremity Trepomonas. 

Four equal filaments in front, two thicker behind. . . Hexamita. 

A second filament proceeding from the same point 
as the flagelliform filament, but thicker trailing and 
retractile Heteromita. 

A filament and vibratile cilia Trichomonas, 

Groups always free and whirling Uvella. 

Groups fixed to the extremity of a branching polypdom Anthophya. 



Several 
Filaments 



As to the mode of propagation of the Monadina, Dujardin states 
that he has never witnessed the spontaneous fission described by 
Ehrenberg, but thinks it more probable that their multiplication 
takes place by the separation of a lobe, or of the termination of an 
expansion. 

"We may gather, from the following summing up given by 
Dugardin, after his general indications of the genera of Monadina, 
what value he assigns, in the present state of knowledge, to any 
attempted classification of such minute creatures. He remarks, 
" But these generic distinctions are entirely artificial, and simply 
intended to facilitate the naming of Infusoria one may have met 
with, in such and such an infusion, and which better known, may 
prove in some instances but varieties of a single species." (Hist. 
Infus. p. 273.) 



120 



DKSCRIPTTON OF 



A recent paper, published by M. Agassiz, makes us acquainted 
with the views of that eminent natiiralist on the questio vexata of the 
relations of the Infusoria to other organized beings. He observes, 
*■' Recent investigations upon the so-called Anentera have satisfac- 
toiily shewn, in my opinion, and in that of most competent observers, 
that this ty^e of Ebrenberg's Pohjgo.strica without gastric cavities, 
and without alimentary tube, are really plants belonging to the order 
of Algae in the widest extension of this group, wliile most of the 
Monas tribe are merely moveable germs of various kinds of other 
Algae." (Ann. Nat. Hist. 1850. p. 156.) 

The above \T.ews opposed to the animal natiu'e of the Mbnadt'na 
are given m extenso, but the candid observer will find, if he examines 
these organisms, that the balance is in favour of theh' being animal. 
The extreme minuteness of these animalcules renders it difficult for 
the mind to comprehend them or compare them with large animals, 
but difference of magnitude, however great, is no actual bar to -sdtal 
power, while the cilia of the animalcule connects man himself with 
it, the fia'st moving instrument in the human embrj-o being a cilium, 
which is retained to the end of life. 

Genus Monas. — TJie Monads. — The animalcules of this genus — the 
true Monads — are described (see Table) as being deficient of the eye, 
projecting lip and tail, and always swimming in the direction of the 
longitudinal axis of the body, their mouth being situated at the 
anterior part. It is another distinguishing character of the true 
Monad that it is never seen to cluster with others of its genus, so as 
to form a berry-Hke mass, and hence it is designated single, in con- 
tradistinction to aggregate. At present, there are twenty- six species 
of this gemis known — two green, two yellowish, three inclining to 
red, and the remainder coloiu'less ; but it should be mentioned, that 
although there be colour, it must not be regarded as a characteristic 
to be entirely relied upon. Monads may often be present in water, 
under inspection, ^dthout being seen, tlxrough the want of a 
competent magnifying power. They will be sought for in vain 
with a power of less than 300 diameters, and even this, in some 
cases, will be found insufficient. They are besides, as a genus, 
difficult to be accurately determined, not only on account of their 
exceeding minuteness, but because the young of animalcules of 



MonadinaJ] infusorial animalcules. 121 

other genera are bo likely to be mistaken for them ; for instance, 
the young of the Bacterium, Vibrio, Uvella, Pohjtoma, Pandorina, 
Gonium, &c., when they have separated from their clusters, or 
issued from their common envelopes. And this difficulty in discri- 
minating them wiU be more likely to happen when they are not 
observed, whilst undergoing the process of self-division, or when 
seen in water containing but a small number of them; in which 
cases, however anxious we may be to ascertain their name, we must 
often rest contented with an approximation to the truth. When 
the water swarms with the creatures, the decision will be far easier, 
and more to be relied upon, as the characters are then more easily 
discoverable from the numerous vital relationships presented to us. 
The obser^'er may, however, be guided to a certain extent by the 
following rule : — Suppose that in a drop of water containing species 
of the genus Vibrio, Bacterium, Uvella, or Polytoma (easily distin- 
guished by their clustering forms), separate Monad-like bodies 
were to be observed ; the probability is that they would be either 
single forms, or the yoimg of these clustering animalcules, and if 
there were no great difference in the size of the separate individuals 
and those forming the clusters, this conclusion would be generally 
correct ; and this rule applies equally to those green Monad-like 
creatures found amongst Pandorina and Gonia. The young of the 
CMamidomonas puhisculus is very deceptive, and may often be mis- 
taken for an illoricated and eye-less green Monad. 

The onl)- locomotive organ which has been discovered in the 
Monad genus is the single filiform proboscis issuing from near the 
mouth. The numerous cilia sometimes apparent thereabouts are 
nothing more than this proboscis in a state of vibratory or rotatory 
motion. This organ, Ehrenberg observes, has a twofold office to 
perform, the one being locomotive, and the other to provide the 
creature with food ; hence I have called it a purveying organ. 

The nutritive apparatus is readily seen in some of the species in 
its natural state (instance the M. guttula and M. vivipara), without 
the aid of coloured food ; in others {M. termo, M. guttula and M. 
gocialis), it may be demonstrated by the latter means. It consists of 
several distinct or separate cells (from eight to twenty) which are 
not all filled at the same time, and which are, for the most part, 

k: 



122 DESCRii'TxoN Of \^Poli/(jastrica. 

invisible wlien empty, but when distended mth a limpid fluid, 
appear like so many lucid resides within the creatures. 

The propagative ajjparatus has been particularly noticed in the 
species M. guttuJa and M. viviimra. It consists of a vast number of 
granules formed into a net-like mass, and dispersed generally 
throughout the creature, and of a comparatively large spherical 
glandular body, which separates by the process of self-division. 

Monads propagate also by another method, namely, by a self- 
diyision of the creature, either transversely, as with the Monas 
gidtula, M. hi/aUna, M. gliscens, M. Okenii, and 31. soeialis ; or longi- 
tudinally, as with the II. punctum (see fig. 2) ; both methods have 
been observed in M. tivipara. The formation of gemmules has not 
been perceived in this genus. 

Ehrenberg supposes that they are endowed with the faculty of 
sensation, and that this is shewn by the alternate vibration and 
quiescence of the proboscis, when the creatm-e is in a place abun- 
dantly supplied with food. In some of the species an eye-like organ 
has been discerned, but as the species of each genus shoiild be 
reduced to the rule of a special organ, characterizing a particular 
genus, these are not considered as true Monads, but form distinct 
genera, as Microglena, &c. 

As the Infusoria of this genus are chiefly curious on account of 
their extreme minuteness, and in no other respect, the species are 
not deemed of sufficient interest to be expatiated upon at any great 
length ; only their leading chai'acters and size, are therefore given. 
And we may I'emark, generally, that most of them ai-e inhabitants 
of water in which organic matter is undergoing decomposition. 

The Monads are arranged imder tAVo divisions, according to their 
external forms. The fiLrst division contains all those of a globular 
or oval shape (globular Monads) ; second those of a lengthened fonn, 
more than twice as long as broad (elongated Monads). 

A. — Globulae Monads. 

{a). True Glohilar or Sphero- Monads — colourless or whitish. 

MoKAS crepusculum — The twilight Monad. — The animalcules of this 
species are the smallest of all living creatm-es. They are of a spheroidal 
fonn and hyaline, although, when seen in masses, with the naked eye, 



Mon'tdina.'] infusoria ANisiAT.rrr.Es. 123 

they appear of a whitish hue. They are active, and feed on animal 
as well as fungoid substances. They are found in water wherein 
ajiimal matter is held in solution, but as the decomposition of the 
animal matter proceeds, the animalcules die, and their bodies may 
be seen rising to the surface of the Avater, and forming a thick and 
colourless gelatinous stratum. Group 1, in the engraving is magnified 
800 diameters. They rarely attain to I- 12,00th of an inch in 
diameter, and never exceed it. 

MoxAS termo (M). Tlie end or limit Monad, so named from its 
having been supposed to be the limit of animal organization. Active, 
herbivorous, found in stagnant water, and increases rapidly where 
there is an abundance of vegetable matter undergoing decomposition. 
Size 1 -6000th, although some are not one half or even a third of 
that measui'ement. 

M. guttula (M). The drop Monad. — Inactive. May be preserved 
by drying. Twelve stomach-cells may be seen by the aid of indigo 
or carmine. Surface appears granulated. Found in vessels of water 
containing jilauts or flowers. Size 1 -2300th, or less. 

M. fivipara. The riviparous Monad. — Inactive. Found in stag- 
nant water (**), coloured. Size, I -620th, or less. 

M. grandis. — The great Monad is of a greenish colour except near 
the mouth. Proboscis short, l-3rd or l-4th the length of the body. 
It is sluggish. Found in marsh water, very rare. Size 1 -430th. 

M. hicolor. The Two-coloured Monad. — Colourless, excepting one 
or two green spots -wdthin it ; attenuated anteriorly. Motion vacil- 
lating. Size l-1440th. 

M. ochracea. The ochre-eolonred Monas. — Yellow-ochre colour. 
Found in water-eoui-scs. Size 1 -6000th at most. 

M, erubescens. The pale-red Monad. — Rose-coloured, and with a 
slow but continual motion. Found in salt water. Size 1-1 728th. 

M. vinosa. The wine Monad. — Colour of red wine. Tremulous 
motion. Eejeets coloured food. Found in vegetable infusions- 
Size from l-12,000th to l-6000th. 

{h). 0ml or Egg-sha2)ed Monads — all colourless. 

M. kolpoda. — Vacillating motion. Discovered in water in the silver 
mines of Siberia, Size 1- 7200th. 

K 2 



124 DESCRIPTION OF [PoTygastrica. 

MowAS enchehjs. The flash-shaped Blonad. — Contiatious bIow 
motion. Found in marsh water. Size l-1200tli to l-960tli. 

M. nmlra. The shadow Monad. — Rapid motion. Fotind among 
fresli conferva?. Size 1 -2400th. 

M. hijalina. The diaphanous Monad. — Active, and seems to leap 
or jump. Found in stale water in glass vessels. Size 1 -6000th to 
l-2880th. 

M. gliscens. The gliding Monad — Gliding motion. Foimd in 
■watery infasions of the stinging nettle. Size l-4500th. 

M. oralis. The little Egg-shaped Monad. — Tremulous motion. 
Found in water of the Anodonta Mollusca. Size 1 -9600th. 

M. mica. The glittering Monad. — Eotatory and vacillatiag motion. 
Inhabits clear fresh water. Size l-1440th to l-1200th. 

M. punctum. The point egg-shaped Monad. — Revolves on the 
longitudinal axis of its body. (See engi'aving, group 2 ; the lower 
figure exliibits one imdergoing longitudinal division.) Found in 
water with tannin. Size 1-11 50th. 

B. — ^Elongated Mojs^ads. — {a). True Elongated Monads. 

M. cylindrica. The cylinder-shaped Monad. — Solitary, colourless, 
revolves as it progresses. Found in salt water. Size 1-11 50th. 

M. Okenii. Okens elongated Monad. — Red, revolving, vibratory 
motion, social. Found in rimuing water. Size l-2300th. 

(J)). Conical. 

M. deses. The lazy Monad. — Green, solitary. Found in water 
from laills. Size l-1200th. 

M. socialis. The social Monad. Colourless, social. Found in 
water-butts. Size 1 -700th. 

((?). Top-shaped. 

M. flavirans. The yellow Monad. — Social, gliding motion. Found 
in ditch-water. Size 1-1 720th. 

{d). Hpindle-shaped (*), colourless. 

M. simplex. The simple spindle Monad. — Gliding and rotary motion. 
Found in water of the ISile, and at Berlin. Size 1-1 720th. 

M. inanis. The empty spindle Monad. Vacillating motion. Found 
in stagnant and foul water. Size l-3G00th. 



Monadina.^ infu3orial animalcules. 125 

MoNAs scintillana. The sparkling spindle Monad. — Very active. 
Vacillating motion. Found amongst fresh water confervae, &c. Size 
l-eOOOth to l-4600tli. 

M. Lumalii. — Of a deep red colour : they occur in vast numbers 
in the saltmarsh-Tvater of the Mediterranean, to which they give a 
deep blood colour. Discovered by M. Joly. 

M. prodigiosa. — A very minute red Monad, so named by Ehrenberg, 
from its siu-prisingly rapid development. It is this animalcule 
which has produced the blood-like spots occasionally appearing 
mysteriously on bread and other farinaceous substances, and which 
have ever been a cause of terror to the supcrstitioiis. 

Being desu'ous of making this manual as complete as possible, the 
following species, described by M. Dujardin, are inserted ; but it may 
be that some of them refer to monads ah'eady characterized, but 
differently named. 

M. lens. — Figiu'e rounded or discoid ; sm-face in appearance tuber- 
cular. Size 1 -5200th to 3-5 200th. Tliis species, one of the most 
frequent in animal or vegetable infusions, has been recognised by 
most of the ancient micrographers. It sends out obliquely a flagel- 
liform filament, three, four, or even five times as long as the body, 
and mobile in all its length. 

M. concava. — Body circular, concave on one side, thin in the 
centre, margin tumid. Filament long, moveable throughout. Found 
in marsh water, Toulouse, 1 -2080th. 

M. glohdosus. — Body globular ; fonn mostly constant; compressed 
at origin of filament ; more globular than M. lens, and its surface 
smooth. Found in sea water at Cette, France. Size 1 -2000th. 

M. elongata. — Body elongate ; nodular, flexible, of variable form. 
Length l-1200th. Found in marsh water. 

M. (dtenuata. — Body ovoid, tapering at each extremity, nodular, 
vaculse large and distinct, as is also its filament. Size l-1660th. 

M. ohlonga. — Body ovoid, oblong, unequal, tubercular, hollowed 
by vacuolae. Size 1 -3600th. Found in vegetable infusions. 

M. nodosa. — Body oblong, irregular, nodose, tapering behind, 
truncate in front, filament arising from centre of truncate extremity. 
Size 1-21 70th. Found in sea water at Cette, France. 

M. gihhosa. — Body oblong, angular, irregularlv distended and 



126 DESCRIPTION OF \_Polygaitrica. 

gibbose, filament springing mostly from an anterior constriction. 
Length l-2000tb. Found in infusions of gelatine. 

MoNAS varians. — Body oblong, narrower in front, very soft, and 
variable in form. Length l-650th to l-700th. 

M. intestinalis. — Body very elongated, foiTa constantly changing, 
or one end rounded, the other tapering, to terminate in a long fila- 
ment, motion undulatory. Length 1 -1600th. Found in the excre- 
ment of a newt {Triton pahni2)es). " I think this is one of the 
species of Bodo, described by Ehrenberg as met with in the intes- 
tines of frogs." (Duj.) 

M. fluida. — Body soft, semi-fluid, fonn variable, iiTCgularly ovoid, 
sometimes constricted posteriorly, hollowed by large vacuoles. Size 
l-2600th. 

M. comtricta. — Body elongated, four or five times longer than 
broad; constricted, often much so at the centre. Length l-1300th. 

Genus TJvella. The grape Monads. — The species of this genus are 
very well characterised by their aggregating together occasionally, 
so as to form a grape or mulberry-like mass, and by their generally 
possessing two (?) hair-like proboscides at the mouth. Like the 
beings forming the genus Manas, they are deficient of the projecting 
lips, visual organ, and tail, and have the mouth situated at the 
anterior extremity. They progress also in the direction of the 
longest axis of their body, and are capable of complete self-division. 
There are six species — two green, and the remainder colourless. 

This genus belongs to the aggregate Monadina of Dujardin, and is 
thus defined by him, " animals globular or ovoid, having a single 
flagelliform filament, and living aggregated iu spherical masses, 
freely moving about in the liquid." He further observes that 
isolated individuals are not at all distinguishable from simple Monads, 
that there is no good reason to suppose the UveUa to live alternately 
isolated, and in masses, and hence that the absence of this circum- 
stance cannot be employed to separate them from Polytoma, or its 
existence to characterize the latter. 

Dujardin describes only two species, viz., U. virescens, and U. 
ro8acea=^U. glaucoma. (Ehi'.) 

U. virescens. {Folvox ma, M.) — Body ovate, and of the colour 
that gives rise to its specific name. Found in serrated groups 



Monadina.'} ixTTso-RTa. aktat xt.cft.-es. 127 

amongst confervaj and lomna. Size l-2000tl) ; diameter of cluster 
l-280th. 

TJvELLA chamaemopim. — Smaller than the preceding one. Found 
in water-butts. Size 1 -2880th ; diameter of cluster 1-5 70th. 

U. tiva. — Has indistinct vesicles, and is vciy small. Found in 
stagnant water. Size l-4800th; diameter of cluster l-960th. 

U. atomus. {JTotias atomus, M. lens et Volvox socialis, M.) — 
Voracious, with large vesicles. Size 1 -6900th to 1 -3406th; diameter 
of cluster l-1150th. 

U. glaucoma. ( Vohox socialis, M.) — Form oval, but inclining to 
conical, with the posterior extremity attenuated as it advances in 
age. Hyaline, with large vesicles, and two evident filiform probos- 
cides: individuals loosely aggregated. In 1831, Ehrenberg first 
observed a vibration at its anterior part, and. its reception of coloured 
food. In 1835, he discovered within the body of this minute 
creatui'e some gi'een Monads which it had eaten, and by which it 
was proved to subsist by prey. When fed on indigo, as many as 
twelve stomachs were filled, and it has been sometimes seen to void 
little blue particles, like undigested matter, from its mouth. With 
a power of 800 diameters, a great number of small colourless 
granules, having the appearance and form of ova, may be discerned 
lying between the nuti'itive sacs. It increases both by transverse 
and by longitudinal fission. Engi-aving, group 3, represents a 
cluster of these creatures ; figiu'es 4 and 5, separate young ones ; 
and 6, an old one. They are magnified about 350 diameters. The 
indi\'iduals, when full grown, are elongated. Found in water-butts. 
Size l-2300th to l-2350th; diameter of cluster l-430th. 

U. hodo. — Fore part of the body rounded ; posterior attenuated. 
It is of a beautiful gi-een colour ; found in stagnant water. Size 
l-4030th to l-3450th; diameter of cluster l-2350th. 

Genus Miceoglena. — TJie eye Monads. — This genus is essen- 
tially characterized by all its species having a minute red eye-like 
speck situated at the anterior part of the body. In other respects 
they resemble time Monads, being deficient of the projecting lips 
and tail, and swimming in the direction of the long axis of the body. 
They possess a very delicate flagelliform proboscis, of simple sti-ueture. 



128 DE9CRIPTIOX ot [Poli/ffasfrica^ 

They multiply by a complete self-(ii\T.sion of the hody. Two species 
only are known, the one yellow, and the other green. 

We now approach the description of living creatures, whose or- 
ganization, on account of their magnitude, is rendered more apparent 
to us. The red eye-like speck, the distinguishing feature of this 
genus, Ehrenberg assumed to be a rudimentary visual organ, al- 
though nervous ganglia subservient to it have not been perceived, 
as in the still larger Infusiora, the Rotatoria, and in the single-eyed 
genus of Entomostraceans, the Bothnia. This organ, together with 
the proboscis, — its locomotive and purveying instrument, the beau- 
tiful green homogenous granules (seen in M. monadina, which, by 
their shape and situation in the body, leave no reasonable doubt of 
theii' being ova,) and the grey rolled band-like seminal gland, de- 
monstrate that these living atoms are endowed with an organization 
(a sensitive one two) as comfortable to their particular uses, and aa 
well adapted to supply the wants of the creatures, as those even in 
the largest fish. Still are we left to conjectm^e "with respect to their 
possessing a vascular system or not ; it has never been perceived, and 
we can only argue, as we have done already, that if there be one, the 
vessels in being so minute must necessarily be of such delicate 
structure, that we may not as yet have foiind out the means of 
making ourselves acquainted with them. 

MiCE0GLEXAj9«<?«c^?/f?'« {Enchelys pimctifera M.) — Colour yellowish, 
form oval, or almost conical ; terminated acutely at the posterior ex- 
tremity. Eye, red with a blackish central spot, as if a secondary visual 
appendage. Eound among slimy water plants. Size 1 -620th. 

M. monadina. — Beautiful green-colour ; form ovate, rounded 
equally at both extremities ; a distinct single red eye, proboscis 
nearly as long as its body ; motion vibrating, rotatory on its long axis. 
Figures 12, 13, and 14, represent three animalcules magnified, the 
first 800 diameters, exhibiting all the internal organization noted 
above. Found among slimy water-plants (Hampstead and Finchley). 
Size l-2300th to l-720th. 

Genus Chloeastee. — Solitaiy, without tail: mouth terminal : 
with a frontal ocellus, central portion of body with radiating rows 
of raised points fveruccce.J It is allied to the genera Glenomorum. 



Monadina-I iNFrsoRTAi. axtmalcx^t-fs. 129^ 

and Phacelomonas ; but differs from tlie former in being solitary — 
not clusteiing, and by the greater number of proboscides ; whilst the 
last are fewer than in Phacelomonas. This is a new genus es- 
tablished by Ehrenberg. 

Chlorastek gyrans. — Green ; central part of body fusiform ; both 
extremities acute ; central rays in a whorl of four. Proboscides 4-5. 
Size 1632-a. 

Genus Phacelomonas. The fan Monads. — The distinguishing cha- 
racters of this genus are the numeroixs proboscides placed roimd the 
mouth of the creature, forming as it were a wreath of cilia, and 
from 8 to 10 in number. In other respects it resembles Microglena: 
it has the small red eye, the truncated mouth at the anterior ex- 
tremity, and is deficient of the tail. It swims in the direction of the 
longitudinal axis, and its self-division is simple and complete, but 
not constant in occurrence. Many stomach-cells have been observed 
within the body, but they have not been seen to admit coloiu'ed food . 
This genus has not been illustrated by Ehi-enberg. 

M. puJviscuhis {Jlonas pidvisculus, M.) — Form oblong or slightly 
conical, attenuated posteriorly, and of a beautiful green colour. 
Just previous to self di-vision, its body becomes cyliadrical, then con- 
tracts at the centre ; but when djing it changes to a globular shape. 
In swimming, it turns quickly upon its longitudinal axis, without 
any vibration. This animalcule demonstrates the fact, that pro- 
boscides and cilia are organs not materially different from each other. 
Found in green puddles. Size 1-11 52nd. 

Genus Glen-qmokum. The bride Monads. — This genus is especially 
indicated by its possessing a single red eye, a truncated mouth, and 
double filiform proboscis ; by its being destitute of a tail, by the 
individuals moving on the long axis of the body, by their self-divi- 
ding simply and completely into two, or not dividing at all ; and by 
their volunta/rily clustering, as occasion may require, so as to give 
themselves the resemblance of a bunch of gi'apes. 

In this enumeration of the characters belonging to this genus, we 
are presented with an excellent illustration of the table (and one that 
exceedingly well explains its use), under which all the genera of the 
family Monadina are arranged, so as to exemplify in what respects 
they are alike, and in what they differ from each other. (For ex- 



130 DKSCRTPTTON OF [Poli/ffasfrtca. 

ample, see Table, p. 117.) The Glenomonim closely resembles the 
Vvella, but differs from that genus by the superaddition of the red 
eye ; it differs from Monm and lEcrocjlena in occasionally aggregating 
from Chilomonas, in being deficient of the projecting lips ; from Bodo, 
in not having the tail ; fi'om Phacelomonas, by the double proboscis ; 
from BoxococcuH, by swimming, instead of rolling over or revolving 
in the water ; and from Polytoma, by never appearing in clusters 
whilst undergoing self-division. 

Glenemoetjm tingens. — Body fusiform, of a beautiful gi'een colour, 
and three or four times longer than it is broad. Its double proboscis is 
exceedingly delicate, and about half the length of its body; within it 
may be seen some small whitish vesicles, the stomach-cells, and also 
some minute granules, which give rise to the green colour, and may be 
considered ova. About the centre of the body is a large transparent 
colourless organ, which Ehrenbcrg supposes to be of a male sexual 
nature. The beautiful red eye is fijs^ed internally, about one-thu'd 
from the anterior extremity of the body. These animalcules con- 
stitute a great portion of the green matter commonly seen on stagnant 
water, and discovered by Priestley. They appear to be nearly allied 
to Cercaria viridis, differing from this only in magnitude, and in the 
unalterable form of their bodies. Figure 15 represents two clusters ; 
16, single ones, magnified 250 times; 17, another magnified about 
450 diameters. Found plentiful at Hampstead. Size 1 -3600th to 
1-1 700th. 

Genus Doxococctrs. Tlie revolving Monads. — The individuals of this 
genus differ from those of the whole family Monadina by the singularity 
of theii- motion, which may be defined to be neither that of swim- 
ming nor of rotation, but a sort of rolling over and over. In other 
particulars they are like the Monads. They have the same imvary- 
ing form, and are destitute of the eye, projecting lips, and tail. Their 
self-division is simple and complete, or they do not divide at all, in 
which ease they increase by ova. These character are sufficient to 
distinguish them from all other Infusoria, and to justify their being 
placed in the family Monadina. Four species are known. 

D. glohdm ( Volvox globulus, M.y Form subglobose or ovate ; fran- 
sparent as water ; easily known by its tedious rolling motion ; mouth 
not discerned. Found in salt water. Size 1 -860th. 



Monadina ] infusorial ANiMALcrtEs. 131 

Doxococcus ruber. — Form globular ; coloured brick red, opaque. 
Ebreuberg appears to doubt whether this animalcule holds its proper 
situation here, or whether it should be placed with the gen is Trache- 
lomonas, though its motion is veiy pecidiar ; and he has not been able 
to satisfy himself of the existence of a lorica, or shell, enveloping the 
creature. Group 18 represents three magnified individuals. Found 
amongst confervae, &c. Size 1-1 720th. 

D. pulvisculus. — Form perfectly (?) globular ; colour gi'een, but 
opaque. Found amongst confervse. Size not exceeding l-1280th. 

D. tnequalis. Form irregularly globular ; transparent, and covered 
with green spots. Found amongst confervse. Size 1 -2400th. 

Genus Chilomonas. T/te hp-monads constitute but a small genus. 
They are characterized by the oblique position of the mouth, with 
respect to the longitudinal axis of their bodies, which occasions an 
overhanging or projecting form above the mouth, of a lip-like 
appearance. All the species propel themselves in the direction of the 
long axis of the body. Their form is invariable, and they are devoid 
both of the eye and tail. Wliethcr the projecting lip is furnished 
with cilia, or with a double flagelliform proboscis, Ehrenberg has not 
satisfactorily determined. He states, however, that two proboscides 
are to be distinctly seen on the C. Paramecium, whilst on the C. des- 
truens there is a number of cilia, which are not quite so apparent. 
Their self-division is either simple and complete, or they do not 
divide. 

Dujardin's characters of this genus are, ''Animal with an ovoid 
oblong body, obliquely notched in front, with a very slender filament 
proceeding from the bottom of the notch. Movement from before, 
backwards on its centre. It is with doubt that I refer the Infusoria 
I thus name to the genus Chtlomonas of Ehrenberg. The mode of 
insertion of the filament behind a projecting lip-like portion, ap- 
proaches the animals to the Euglena and to certain Theca monadina,- 
but I cannot discover any trace of an integument, either contractile 
or resistant." 

C. volvox. — Form ovate ; attenuated and trimcated anteriorly ; 
transparent and colourless ; projecting lip long ; they will feed on 
indigo. Found in stagnant water. Size 1-1 440th. 

C. po/ramecium. — Form oblong, keeled longitudinally, colour re- 



132 DESCRIPTION OF [Polygustrica, 

sembling dirty water. This animalcule is easily distingxiished by its 
shape and peculiar lip-like process. With a power of about 240, 
numerous digestive cells are visible ; and with 380, the two probos- 
cides, which are half the length of the body, may be perceived. It 
moves in the direction of its long axis, but in a fluctuating or 
wavering manner. It sometimes clusters. Group 19 represents two 
of these creatiu'es magnified 380 times, and six others less magnified. 
Three are clustered. Found in water wherein wheaten bread has 
been steeped. Size 1-1 020th. 

Chilomonas destruens. — Form oblong, but variable, on account of 
its softness. Faint yellow, nearly colourless. Found in salt and fresh 
water, and in the bodies of dead Rotatoria, for instance, Anuraa 
JoUacea, and Monocerca rattus. Size 1 -860th. 

C. granulosa (Duj.) — Body colourless, oblong, larger anteriorly 
than posteriorly, of almost invariable form, although of gelatinous 
consistence, filled with granules which seem to project from its sur- 
face. Filament flagelliform, very fine, arising from an oblique notch. 
Length l-940th to l-850th. 

C. ohiiqua. — Body ovoid, or pyrifonn, nodular of variable form, 
with its filament arising laterally. Length 1 -2600th. 

Genus BoDO. The tailed Monads. The caudal appendage at the 
posterior extremity of these animalcules is a decisive character of 
the genus. In other respects, the species may be described as being 
eyeless, and ha%-ing the terminal mouth furnished with a single (?) 
filiform proboscis, and as undergoing self- division, simply and com- 
pletely into two, or not dividing at all. These creatures never con- 
stitute true or perfect clusters, like some of the family Monadina, 
although, like the UveJIa, they occasionally enter into social compact. 
In B. grandis, several digestive sacs have been observed, and (as also 
in the B. intestinalis) a simple (perhaps double ?) proboscis. The 
B. didymus has been known to divide transversely. Only one of the 
species of this genus ha^^ng fallen under my own investigation, the 
account of them here given is entirely abstracted from Die Infusions- 
thicrchen. 

This genus Bodo partly comprehends the genera Kexamita, A^npM- 
tnonas, and Cercomonas, of Dujardin, which are with others introduced 
S5 addenda to this family Monadina. 



Monadina.l iNFrsoHiAL animalcules. 133 

BoDO intestinal is. — Fonn almost conical, tail of equal length with 
the body, transparent and colourless. Found in several living animals, 
such as frogs, toads, &c. In the grey and edible frogs, amongst the 
watery mucus of the alimentary canal, Ehrenberg has observed great 
numbers of these creatures, and remarks that the Cercaria gijrinus of 
Miiller (a different auimalciile) uiiglit pass as a representation of 
this species, and that it was confounded by its discoverer with the 
spermatic animalcules. G^roup 20 represents them magnified about 
300 diameters. Size 1-1 720th. 

B. rananim. — Body turgid, ventricles indistinct. Found in live 
fi'ogs, with the preceding species, and with the Burs aria rananim. 
Size 1-1 440th. 

B. viridis. — Form neai'ly globular, tail very short, colour green. 
Found amongst eonfervae. Size l-2400th. 

B. socialis. [Monas lens, M.)— Form ovate or subglobose; tail 
often longer than the body ; transparent and colourless. Clusters 
into a mulberry shape. Single forms are sometimes observed hop- 
ping. Common in stagnant water. Size 1 -2970th. 

B. vorticellaris. The bell-shaped Bodo. — Body tlu-ee times as 
long as it is broad ; tail very short. Found in fr-esh water. Size 
l-11200th. 

B. didipnm. The douhle-tailed Bodo. — Body generally constricted 
about midway, tail short. Size l-9600lh. 

'Q. saltans. — Very small ; body with ample ventricles; tail short. 
This creature, most probably ft^om its small size, has been mistaken 
for Miiller' s Monas termo, but its brisk leaping movement wiU suffi- 
ciently distinguish it. Size 1-1 200th. 

B. grandis. — Form oblong, vesicles ample, tail rigid setaceous, 
affixed to the abdomen. Found in stagnant water. Size l-864th. 

B. oystea. — Body globular; the anterior three-fourths occupied 
with vesicles, the rest hyaline ; length of tail four times the diameter 
of body. This active creatiu-e I discovered in the liquor of an 
oyster, swimming freely among the ova (Sept. 1834.) Diameter 
1 -2000th. 

The following genera named and described by Dujardin, are intro- 
duced into his family Monadvna. 

Genus Cycliditjm, (D.) — Body discoid, compressed, or lameUiform, 



134 DESCRIPTION OF {^Polygaitrica. 

scarcely variable, with a filament, having a thicker and more flexible 
base, than that of 3Ionas, the free extremity only being moved. 

This genus is as yet but artificial, and provisional indeed, true 
monads perfectly developed, may possess a filament, with a thicker 
base ; and again, the constant outline of the body, may be the con- 
sequence of the presence of an integument, in which case the ani- 
malcules in question would be referable to the family 2'hecamonadina. 
Movement slow and unifonn. 

It is to be regi'etted, that Dujardin uses this generic name, as 
Ehrenberg previously employed it to designate certain ciliated ani- 
malcules, which correspond but partially with those of Dujardin, 
under this title. To render this work complete, they are introduced, 
and, we hope the reader will not be confused. Dujardin observes, 
that ''the genus Cychjdmm (Ehr.), contains monads also, and very 
probably some of those to which I have applied the same ' generic' 
name." 

CrcLiDKTM noduiositm. (Duj.) — Body flattened, discoid, with rows 
of nodules and vacuolse, movement extremely slow, Length 1 -5200th. 
Found in water from the Seine. 

C. abscissum. (Duj.) — Body membranous, lamelHform, truncated 
posteriorly, filament rigid, movement slow, regular. (P. 21. f. 15.) 
Length 1-1 040th. 

C. crassum. (Duj.) — Body oval, thick and rounded, filament 
thickened at its base, and rather sinerous ; movements more active, 
zigzag. Length 1 -1090th. Length of filament 1 -600th. 

C. distortrum. (Duj.) — ^Body oval, flat, nodular, irrcgulai'ly bent 
wdth a tumid border. Length l-1800th to l-800th. (P. 21. 
f. 14.) 

" This species is perhaps but one phase of develoj)ment of 
Ilonas lens, it was found in Seine water, kept during three months. 
"When young it has the form of a disc, with a tumid and nodular 
margin; when, however, it has grown larger, it becomes twisted 
upon itself, and its movement irregular. Some individuals offered a 
certain affinity with the Trepomonads, which favoui-s the opinion 
already advanced, that the majority of the Monad ina, are but modi- 
fications of one or of several types." 

Genus Ceecomonas, (D.) — Body rounded or discoid, tubercidar, 



Monadina.'] infusorial animalcules. 135 

"with a posterior variable process in the form of a tail, of greater 
or less length and fineness. 

The Cercomonads differ from the Monads in the postei'ior pro- 
longation, serving by the adhesion of its extremity as a point of 
support, and which is either elongated as a very fine thread, or con- 
tracted into a small tubercle. It is sometimes nearly as fine at the 
anterior filament, and susceptible of an undulatory motion. 'I have 
not unfrequently witnessed the transition of monads to the condition 
of Cercomonads. 

"We may conclude that many of the animalcules described in the 
genus £o(h, (Ehr.), are examples of this genus Cerconionas, Duj., 
although sufficiently marked characters are wanting, in order to dis- 
cover special identity. 

Cycliditjm detracta. — Body discoid, or oblong, granular, with a 
thick tail. Length 1 -7000th., 1 -2300th. 

C. crassicanda. — Body elongated, nodular, flexible or variable form, 
more or less contracted posteriorly into a tail. Length l-3400Lh, 
1 -2600th. 

C. viridis. — Body ovoid, oblong, tubercular, green, prolonged pos- 
teriorly into a tail of vai'j'ing tenuity, or into a rounded lobe, or 
spatidate expansion. Length l-1500th. 

C. lacryma. — Body globular, uneqxial, elongated posteriorly, as a 
long, flexuose tail. Length of body l-5200th., l-3000th. Length 
of tail l-2600th. Length of filament 1 -750th. 

C. accuminata. — Body globular or ovoid, contracted posteriorly 
into a short tail, terminating by a veiy fine filament. Length 
l-2600th., l-1900th. 

C. glohiiJosus. — Body globular, with a filament at each exti-emity 
doiible its length, the anterior one, more actively moved. Length 
1 -2600th. Found in marsh water. 

C. longicmida. — Body fusiform, flexible, terminated posteriorly by 
a long and very slender filament, also flexuose. Length of tail 
l-1800th. 

C. fusiformis. — Body dilated at centre, constricted in front, and 
prolonged behind into a long delicate tail. Length of body 
] -1900th. 

C. cyUndricm — Body cylindrical, elongated constricted posteriorly, 



136 DESCRIPTION OF {Tolygastnca. 

terminated by a long straight, and A-ery thin tail. Length of body 
1-2600. Length of tail the same. 

Cyclidiu-m: truncata. — Body contracted posteriorly, ti'uncate in 
front, and having a filament springing fr-om each of the truncated 
angles, the other angle being extended more or less into a lobe. 
Length l-3000th, l-1900th. 

C. lobata. Body variable in form, tubercular, sending out a flageUi- 
form filament from the end of an anterior lobe, and emittiag also one 
or two other lobes. Length 1-3250, 2-3250. 

Before proceeding with the next genus it is right to mention that 
Dujardin has noted the occurrence of several of the above Cerco- 
monads, in organic infusions in conjunction, particularly with Monas 
lens, and that he inclines to the idea of these differently named 
Infusoria, being but different conditions of the same animalcule. 

Genus AiiPHiMONAS. (Duj.) — Animal of variable uregular form, 
having at least two filaments, of which one is either in front, and 
the other on one side, arising from a consti'iction of the body, or 
both are lateral, and accompanied or not with a caudiform prolonga- 
tion. The leajiing movements of these creatures offer a good character. 

A. dispar. Body oblong, of veiy vaiiable form, one or other of 
its ends constricted, or prolonged laterally into two filaments, or ex- 
hibiting them approximated at the anterior extremity. Length 
1 -3500th to 1 -2900th. Movement active, jerking. 

A. caudata. — Body of very variable form, mostly depressed, tuber- 
cular, convex on one side, angular on the other, with a filament 
proceeding from the summit of each angle. Length 1-21 80th to 
1- 1300th. 

" This species seems to me (says Dujardin) to be allied to the Bodo 
saltans of Ehrenberg. In every example I saw two flagelliform 
filaments, one fi-om the anterior, the other fi-om the lateral angle ; a 
caudiform prolongation obtuse, or drawn out as a third filament, 
often adhered to the slide." 

A. hrachiata. — Under tliis name is indicated an animalcule of the 
family Ilonadina, which Dujardin only once met with, of an ovoid 
or pjiifonn shape, filled with granules, and giving off from its 
narrower anterior end, a simple flexuous filament, together with a 
variable dilated lobe, emitting two other filaments having an undu- 



Monadina.] infusorial animalcules. 137 

latory motion. The animal progressed by leaps, revolving at the 
same time. 

Genus Teepomonas, (D.) — Animals with a compressed body, thicker 
and more rounded posteriorly ; with two anterior ciu-ved narrow lobes, 
each terminated by a flagelliform filament, producing an active 
whii'ling and jerking movement. 

The examples of this genus are very common in aU collections of 
marsh water containing decomposing plants, but are most difficult to 
determine, owing to the ii'regularity of their form and the rapidity 
of their movements. I have rather glimpsed than certainly detected 
their flagelliform filaments, and have in vain attempted accurately 
to delineate them. 

T. affilis. — Body granular, imequal. Length, 1-1 300th. 

Genus Hexamita, (D.) — Animals with an oblong body rounded in 
front ; constricted and bifid or notched behind. Two to four filaments 
extend from the anterior border, and the two posterior lobes are pro- 
longed as two flexuous filaments. 

This genus, characterized by the number of its motor filaments, 
appears sufiiciently distinct from the preceding. Its species occur 
in decomposing marsh water, or in the intestine of Batrachians ; but 
not in artificial infusions. 

H. nodulosa. — Body oblong, with three or four longitudinal rows 
of nodules, the two lateral of which are extended into tapering 
slender lobes, each terminated by a filament. Movement vacillating. 
Length l-1300th to l-1500th. (P. 21. f. 1.) 

H. injlata. — Body oval oblong, rendered almost quadrangular by 
the processes, giving origin to the filaments. Length 1 -600th — 
l-1300th. 

H. intestinalis. — Body fusiform, prolonged into a bifid tail, very 
common in the abdominal cavity of the Batrachia (Frogs and Newts)- 
It moves in a straight line, oscillating from side to side. 

Genus Hetekomita, (D.) — Animals having globular, ovoid, or oblong 
bodies, with two filaments extending from the same point in front, 
one slender undulating, and producing an onward movement, the 
other thicker, stretching posteriorly, free, or contracting adhesion 
with the glass slide, so as to cause a sudden movement backwards. 

The several sections of the Monadina, together with the Thecamo- 

L 



138 DBSCEIPTION OF \^Polygastrica. 

nodina and the Euglenia, contain Infusoria possessing two -filaments, 
by one of whicli they progress, by the other adhere for support to 
any solid body, and produce a sudden movement backwards by its 
contraction. To prevent confounding specimens of these several 
families the same distinctions which mark the Monadina generally, 
must be found in order to constitute the Heteromita members of that^ 
family ; such as the absence of integument, the gelatinous appear- 
ance of the entire mass admitting of agglutination to other objects, 
and the drawing out of its substance into filamentous processes, 
together with the existence of certain corpuscles, which can only 
have penetrated the interior as a consequence of the formation of 
vacuolse at the sm-face. 

Heteromita ovata. — Body ovate, narrower anteriorly, containing 
vacuolae, granules and navicula). Length l-1050th to l-1150th. 
(P. 21. f. 5.) 

This is probably the Bodo grandis of Ehrenberg. His other Soda's 
are not Heteromita, but imperfectly observed Cercomonads or Amphi- 
monads. 

H. gramdmn. — Body globular, surface granular. Length l-2600tli. 
Pound in rather putrid sea water. 

H. angusta. — Body narrow, lanceolate, slightly bent, tapering at 
each end, with a flagelliform and another filament from the same 
point anteriorly, erect at the base, but floating freely the rest of its 
length. Length 1-1 050th 

This is a doubtful species. It is of the shape of a lanceolate leaf, 
with a mid-rib or longitudinal fold. 

Genus Teichomonas, (D.) — Body ovoid or globular, capable of being 
drawn out when adherent, and in this way presenting sometimes a 
caudal prolongation, the anterior flagelliform filament is accompanied 
with a group of vibratile cilia. 

T. vaginalis. — Body gelatinous, nodular, unequal, hollowed by 
vacuola), often adhering to other bodies; movement oscillating. 
Length 1 -2600th. 

T. Limacis. — Body ovoid, smooth pointed at each end and termi- 
nating in front by a flagellifonn filament, from the base of which a row 
of vibratile cUia is directed backwards. Progressive movement active, 
the animalcule at the same time turning on its axis. Length 
1-1 730th. Found in the intestine oi Limax agrestis. 



Hydromorina.'] infusorial ANiMArcuLES. 139 

Genus Anthophtsa, (D.) — Animals ovoid or pynfonn furnislied 
with a single flagclliform filament, and collected at the extremities 
of a branching stem, or polypidom, secreted by them. Groups when 
free resembling those of Uvella. 

The ti'ee-like poly^jary is brown at the base, but clearer and even 
diaphanous at the termination of the branches which appear nodular. 
The groups of animalcules are easily detached from the stem, and 
then commence a rotatoiy movement by the action of the filaments 
of each individual in the group. Detached solitary animalcules move 
like the common monads ^ ith a single filament. 

The branching support at fij'st soft and gelatinous, becomes by 
degrees more consistent, brown, and of a horny character, appearing 
to partake no longer the vitality of the animalcules. 

Only one species is at present known and which is ranged by 
Ehrenberg under the genus Ejpistylis, along with Vorticellina. 

A. MiUleri = Epistilis? vegetans, (P. 21. f. 2. Ehi\) 

We conclude this family with two new genera, named by Werneck, 
(Monatsbericht der Berlin Akad. 1841. p. 377.) and thus briefly 
described. 

Genus AjfCTEnm = Enterodeloiis Bodos, {i.e. according to the no- 
menclature of Ehrenberg. Bodo's furnished with an intestinal tube, ) 
with a moveable setacious foot. 

The existence of an alimentary tube (so supposed), removes the 
Bodo grandis and the six allied species {i.e. the genus Aneyrium,) 
far above the Monadina, of Ehrenberg, whilst the possession of the 
setacious foot also indicates a higher oi'ganization. 

Genus Eketes. — Rudder Monadn ; Loncated Phacelomonads. 

Family.— HYDROMORINA. 

Cha/racters. Anenterous Polygastrica without appendages ; body 
uniform, like that of the Monads ; but by reason of the spontaneous 
fission being imperfect, foiining a moniliform mass or polypary, 
lorica absent. Individuals are at periods set free, which commence the 
same cycle of compound development as the parent being to which 
they originally belonged. 

The genera belonging to this family, ai'e, Folytoma and Spondylo- 

L 2 



140 DESCRIPTION OF {Tolygaslrica. 

mornm. Pohjtoma was described by Ehrenberg in the family Mona- 
dina, but the subsequent discovery of the genus Spandylonomm, 
having the same general characters, and diifering like it from the 
other monads, led him to create this new family Sydomorina to 
embrace the two. 

Genus Polttoma. The Partile Monads. — Mouth truncated, fur- 
nished with a double flagelliform proboscis, situated, as with Monas 
and Uvella, at the anterior extremity of the body ; eye and tail 
wanting. As the young increase in size, the parent body assumes a 
decussated or wrinkled appearance, like a miilberry, thus giving 
signs of its approaching self-division into many sections (as the name 
Pohjtoma denotes), or numerous individuals. It will not imbibe 
colouring matter; but its internal organization bears the usual 
evidences of the Polygastric nutritive system. Its only organ of 
locomotion is the double proboscis. A large contractile vesicle, 
sometimes observable within the creature, Ehrenberg conceives to 
belong to the male propagative apparatus. It increases by spon- 
taneous self-division of its body, both transversely and longitudinally, 
thus dissolving, as it were, its berry-like cluster into many indi- 
viduals. It was known to MiiUer and "Wrisberg. One species has 
been recognized. 

P. uvella. {Monas uva, M.) — Colourless, of an oval or oblong 
form, equally obtuse at both extremities. It is often abundant 
in water, where animal matters are in solution, upon which it 
appears to be nourished. It is generally in company with species 
of Vibrio and Spirillum, and sometimes with Uvella uva, and 
U. atomus, in water-butts. 

Figures 8 and 9 represent two individuals; figure 10, another 
about to divide longitudinally ; a cluster of eight is seen at fig. 7 ; 
and a matured one on the point of separating at figure 1 1 . Pigui'e 
9 is magnified 800 diameters, showing the double proboscis very 
distinctly ; and its body seems enveloped in an outer tunic (probably 
induced by the peculiar contraction), which disappears when the 
division is completed. Size from 1 -200th to 1 -900th. Diameter of 
clusters 1 -380th. 

Genus Spondylomoettm. — The members of this genus are furnished 
with adorsal ocellus ; are destitute of a tail, and in consequence o^ 



Cryptomonadina.'] infusokial animalcules. 141 

their imperfect peculiar self -division, form a compovmd body 
{polypary, ) resembling a whorl, or cluster of berries. 

S. quaternarium. — Animalcides alternating in a group of four, of 
which the terminal one is the most slender ; coloiu- green ; probos- 
cides 4 to 5. Length of polj^)ary 1- 570th; of each animalcule 
1-1 728th. 

Family.— CRYPTOMONADINA. 

The family Cryjotomonadina exhibits aU the characteristics of the 
Monadina, (and no certain or definite ones of any other family,) they 
ai-e besides furnished with a distinct gelatinous, membranous, or 
hard induvium, or shell-like substance, termed a lorica, in which 
they are more or less enclosed. Considering them as a family, their 
organization has been determined as completely as that of the Mona- 
dina, or even of the larger Pohjgastrica ; although something more 
is yet to be learnt of the species indi-vidually. The lorica, or integu- 
ment covering these creatiu'es, is of different forms ; sometimes 
having the figure of an open shield fscutellumj, at others of a closed 
box or a pitcher furceolusj. Locomotive organs are clearly percep- 
tible in aU the genera, excepting, perhaps, the genus Lagenella, and 
even in this. Dr. Werneck is of opinion that he has discerned them. 
They consist of two delicate, filiform, and generally reti'actile pro- 
cesses, issuing ii-om the margin of the mouth, and capable of being 
put into very powerful rotatory motion. We shall designate them, 
as with the Monads, proboscides. The nutritive apparatus of these 
creatures has not yet been demonstrated by the application of coloured 
artificial food ; but with six or seven species (nearly one-half the 
family) internal cells have been discovered. In two genera, a sen- 
sitive system may be presiuned to exist, from a coloured spot or eye- 
like appearance being present at the fore part of the body. From 
the position of this organ of vision, the dorsal line may be readily 
conceived, so as to indicate a right and left side of the creature. 
The individuals either self-divide simply and completely, or they do 
not divide at aU. " It is possible," says Ehrenberg, " that the fossil 
animalcules discovered in the flint of chalk and porphyritic forma- 
tions, and named bj- me Pyxidicula (see Plate 12, upper figures) 
belong to the genus Trachelomonas. 



142 DEscBiFTioN OF iPolygastvica. 

The genera liold the following relations : 

fForm short, self-tlivision ) r-T—t^-,--,,. 

Lorica obtuse J longitudinal or wanting ) t-rypiomonas 

and < 

J smooth Form long and toi'tuous ) rv„i,;,i„„, ™„» 

Eye absent i L Self-division transverse ] Opl^idomonas 

Lorica pointed anteriorly Prorocentrum. 

I 

'Lorica with a neck and narrow orifice Lagenella. 

Lorica an open shield ^ Orvnto^lena 
(SfHii'lliinA LTyptogiena. 



Eye present 



Lorica with the orifice | (Scutellum) 

but no neck. 



I Lorica a closed box or ) ^ i, i „ 

I pitcher (tVc.o?«*) j Trachelomonas. 



" Of these genera," says Dujardin, "we accept but two, in 
bringing together the Cryptoglena and Lagenella as subgenera of 
Cryptomonas. Prorocentrum may be the same thing as our Oxyrrhis; 
and we, moreover, unite with Trachelomonas, the genera Chcetotyphla 
and Chcetoglena, placed by Ehi'enberg amongst the Peridinma. "With 
respect to the genus Plxacus, it has been introduced among the 
Euglena by this author, notwithstanding the difference existing in 
the non-contractility of its integument. Lastly, oiu* genus JJiselmis 
corresponds in part to the Chlamidomonas of the same writer." 

Since there is a general correspondence between the family Crypto- 
monadina, of Ehrenberg, and that of Thecamonadina of Dujardin, we 
may append the account of the general characters given by the latter 
author of Thecamonadina. 

The species of this family are readily recognized by the stiffness 
or inflexibility they display while swimming, or when brought into 
contact with other bodies. The lorica of the Prorocentrum and 
Lagenella is at once perceived to be a distinct covei-ing. When any 
doubt, however, exists upon this point, a slight degree of pressure 
in the aquatic live-box, or between two slips of polished glass, will 
easily determine it. The lorica of the Trachelomonas is siliceous, 
and indestructible by fire. 

Genus Ceyptomonas. The loricated Monads. — This genus is essen- 
tially characterized (see the Table) by the species being destitute of 
the visual organ, and having a lorica obtuse, or not attenuated 
anteriorly. Body short, but not filiform ; self-division, if any, longi- 
tudinal ; flagelliform filament very fine. 

Dujardin writes " In this genus Cryptomonas, I comprise all 



Cri/ptomonadina.'\ infusokial axtmalcttles. 143 

Tliceamonadma with a single filament, and with a lorica neither hard 
nor brittle, and whose body is not depressed like that of Phacus or of 
Crumenula, and I moreover do not doubt that when these Infusoria 
are better known, other genera may be distinguished by their more 
or less globular form, by the consistence of theii- envelope, and espe- 
cially by their mode of existence. I already indicate as subgenera, 
Lagenella with an elongated lorica, and Tetrabcena, which live in 
groups of four, without, however, being imited vdthin a common 
envelope. As to the character supplied by the existence of a red 
speck in some indiAdduals, assumed by Ehrenberg to be an eye, I 
cannot discover in it a generic distinction, nor am I able to recognize 
a lorica open on one side (below) like a shield. On the contrary, I 
have always observed the lorica to be closed and entire, though 
sometimes compressed on one side, adapting itself to the Kving mass 
enclosed. The covering in every case is e\'idently larger than the 
contained mass, a diaphanous space intervening between the two 
aj^pearing Kke a ring." 

Crtptomonas curvata. — Porm compressed, slightly bent like the 
letter S, and twice as long as it is broad; coloiu' green. Found 
amongst ConfervsB. Size 1 -570th. 

C. ovata {Enchelys viridis, M.) Form depressed, oval, and twice 
as long as broad ; colour green. Motion slow, vacillating, and 
rotating on the longitudinal axis : but when obstructed, the creature 
is seen to leap. Lorica paper-like, not hard, and the numerous in- 
ternal transparent vesicles perceived amongst the green ova are the 
alimentary sacs. In the middle of the creature there are two or 
three egg-shaped bodies, supposed to be seminal glands, and at the 
posterior part a single variable vesicle of a sexual nature ; self- 
division not observed. Figures 21 and 22 represent two full grown 
creatures (side and back view), magnified 300 diameters ; and fig. 23, 
a young one. Foimd amongst confervas. Size 1-5 70th. 

C. erosa. Body depressed oval, colour green, anterior part hyaline. 
Found in clean water, among confervae. Size 1 -960th. 

C. cylind/rica {JEnchelys viridis, M.) Body elongated, sub-cylindrical, 
three times as long as broad. Found amongst confervas. Size 
almost 1-lOOOth. 

Ceypxomoxas (?) glauca. Form oval, twice as long as broad, an- 



144 DESCEIPTION OF \^Polygastrica 

terior portion truncated with a double flagelliform proboscis. Body 
turgid, and of a blueish green colour. Found with the Chlamido- 
monas pulvisculus. Size 1- 864th. 

Cktptomonas (?) fusca. — Oval, turgid, and of a brown-colour. 
Found amongst confervae. Size l-1500th. 

C. lenticularis. — Form orbicular, resembling a lens ; colour green ; 
lorica thick. Size 1-1 729th. 

" The C. curvata!'' — says Dujardin, " is so compressed that it is 
properly referable to our genus Crumenula,''^ The C. glauca and 
C. fusca, the same observer regards as doubtful species. The two 
foUowing species are described, and named by Dujardin. 

C. globulus. — Body globular, green, often with folds (stripes), 
nearly as large as the diaphanous envelope. Length 1 -2600th., 
1 -2250th. 

C. incequalis, — Body ovoid, gi'een, of less thickness than breadth, 
with a longitudinal depression, and one or two unequal notches in 
the coloiu'ed portion, which is always narrower than the envelope. 
Length 1 -2600th. Found in stagnant sea water, imparting to it a 
green colour. 

C. (Lagexella) inflata. — Body ovoid, enlarged posteriorly ; con- 
tracted anteriorly ; envelope transparent, thicker about the anterior 
neck-like portion ; fiUed with a green substance, having a centi-al 
red speck. Motion zig-zag. Length 1-1 180th. Found in a vase 
of marsh water, with lemna. 

Ehrenberg has described under the name of Lagenella eiicMora, 
an Infusorian of the same size, differing from om's by its more 
elongated form, and especially by the green contents, more com- 
pletely occupying the anterior neck-like portion, whereas in ours 
but a narrow streak is visible. 

C. (Tetkab^na) socialis. Body ovoid, regular, green, with a cen- 
tral red poiat, enveloped by a thick lorica, which is diaphanous, and 
often exhibits a commencing self-division. Animfils living, collected 
in regular groups of four individuals, simply agglutinated, and 
having their filaments directed all to the same side. Length 
1-1 700th, l-1300th. Found in a water-butt, in the King's 
garden, Paris. 

** I should have taken the specimens at first for Gonia, if a trace 



Cryptomonadina.] infusobial animalcules. 145 

of a common enclosing envelope, had been found ; yet I cannot 
doubt, but that they have the closest analogy ^^vith true Gonia, and 
with what Ehi-enbcrg has called Syncrypta in his family Volvocina^ 
One may suppose that the commencing self-fission observed in some 
individuals would give rise to such groups, upon the destruction of 
the lorica (integument) in these diiFcrent genera. This mode of 
propagation occurs, undoubtedly, in most of those ha^'ing a soft gela- 
tinous integ-ument, but in animals like Trachelomonas, whose lorica is 
hard and brittle, we cannot imderstand how multiplication does 
take place." 

In the addenda to his treatise, Dujardin has this remark, "I am 
convinced that my Cryptomonas {Tetralmia), belongs rightly to 
Gonium." 

Genus Ophedomonas. Tlie serpent Monads. The distinguishing 
chai-acters of this genus are its filiform body, absence of the eye, its 
smooth and obtuse lorica, and its transverse but complete self-division. 
It was discovered by Ehrenberg in September, 1836. It is fui-- 
nished with a filiform proboscis, as its organ of locomotion, which, 
together with the tubular lorica, and the numerous digestive sacs, 
form the whole of the organii^ation that has hitherto been de- 
monstrated. Its extremely small ti-ansverse diameter is the gi'eat 
impediment to a better acquaintance with this creature. A\Tiether 
its brown colour is derived or not from the ova within it has not 
been determined. (It has not been figured.) 

0. Jenesis. — Form very thin, cm'ved spii-ally, and equally obtuse 
at both extremities ; colour oKve-brown ; motion brisk. Found only 
at Jena, in well water. Size 1-5 70th. 

0. sanguinea. — ^Yery slender the interspaces between the stomach — 
sacs filled with a red colour. Size 1-5 76th. inch. Found near 
Cilonium, in brackish water. 

Genus Peognocejttetjm. The pointed-shell Monads. — The ani- 
malcules of this genus are destitute of the eye, and have a smooth 
lorica, resembling a little box {urceolus), pointed at the anterior ex- 
tremity. They have a fiUfonn proboscis, and numerous large digestive 
cells in the anterior of the body. Self-division has not been observed. 
" It is worthy of remai'k," says Dr. Ehrenberg, " that the only spec' s 
of this genus with which we are acquainted {^i.e. in 1838), belongs to 



146 DESCRIPTION OF [Polygostrica. 

the luminous creatures of the sea, which, perhaps from some peculiar 
organic relation or condition, yet unknown to us, are instrumental in. 
producing that curious'and certainly vital phenomenon usually termed 
phosphorescent sea." It may he further noticed, that all the luminous 
Infusoria of the sea, hitherto discovered, are characterized as being 
of the same yellowish waxy colour as the species of this genus ; and 
it is probable that this condition is immediately connected with the 
interesting phenomenon in. question. 

Peoeocentetjm micans. — Form oval and compressed, attenuated at 
the posterior part, but dilated and pointed anteriorly; colour of 
yellow-wax. Found in sea water. Figures 24 and 25 exhibit two 
animalcules magnified 300 diameters ; the first is a side view, the 
latter aback view. The proboscis in figure 24 indicates the position 
of the mouth. Size 1 -430th. 

P. viridis. — Figure ovate, suborbicular, turgid ; posterior end 
rounded; anterior shortly pointed; colour green. Size 1-llOOth. 
Found in the Baltic sea. 

Genus Lagenella. — The flash-shaped Monad is distinguished from 
the other loricated Monads by its closed shell being so extended 
anteriorly, as to give it a neck-shaped appearance, like that of a 
bottle or flask. This shell or lorica is perfectly distinct, and as clear 
as crystal. The only part of the organization of the creatui'e at pre- 
sent known is the eye, or bright red speck, which is always to be 
seen in this genus, and the green granules within the body of the 
animalcule, which Ehrenberg supposes to be ova. 

T. eiicMora. — Form oval, neck short and truncated ; lorica crys- 
talline; colour of the body or eggs gi'een. Figui'es 26, 27, and 28, 
are representations of this creature magnified. I'ound amongst con- 
ferva. Size l-1200th. 

Genus Ceyptoglena. The loricated Monads ivith an eye. — This 
genus is distinctly characterized by the species having an open lorica. 
of the form of a shield {scutellum), but folded or rolled inwardly at 
the sides, and without the projecting neck. The eye is perfectly evi- 
dent, and the small digestive cells appear to be covered with gi-een 
egg-like granules. In the species C. conica, traces are seen in the 
centre of the body of a male generative apparatus, in the form of 
two oval glandular masses, of a greyish colour ; in this species also a 



Cr-yptomonadina.'] infusorial animalcules. 147 

double filiform proboscis is seen. Sell'-clivision has not been observed 
in any of the species, which are all of a green coloui'. 

Ckxptoglena conica. — Foiin conical, anteriorly dilated and trun- 
cated, and furnished with two filiform proboscides, half the length of the 
body; posterior acutely attenuated. Colour a blueish green. Group 29 
is a magnified representation of three creatures. They are found in 
great numbers in butts of river water, in company with the Crypto- 
nionas glauca, from which they are readily distingidshed by their 
foi-m, larger size, and red eye. They move briskly in the direction 
of the longitudinal axis of their bodies, but when obstructed, they 
spring or leap out of their coui'se. Size 1- 1100th. 

C. pigra. — Form oval, approaching to globular, and emarginate 
anteriorly ; colour a beautiful green ; movement slow. Foimd in 
water, when covered with ice. Size 1 -3000th. 

C. cmrulescens. — Form depressed, elliptical and emarginate ante- 
riorly ; colour blueish-gi-een ; motion qiuck. Found amongst con- 
fei-vae. Size 1 -6000th 

Genus Teachelomonas. The Monads ivith the trunk. — This genus 
comprehends those loricated animalcules of the family Cryptomo- 
nadina which are possessed of the visual organ, and of a closed box- 
like elongated or spherical lorica, but without the projecting neck. 
They are fui-nished with a single long filifonn proboscis or seta, for 
the purposes heretofore described, and in two species, T. nigricans, 
and T. volvocina, very minute transparent vesicles have been dis- 
cerned, which are most probably theii- digestive sacs. In the species 
T. cylind/rica, egg-like granules are visible. Two species are green, 
and one blackish-brown. It is most pi'obable that those highly in- 
teresting animalcules which enter so abundantly into the silicified 
substances in certain chalk formations belongs to this genus. 

T. nigricans. — Form oval, approaching to globular ; colour rarely 
green, mostly of a reddish or blackish-brown. Eye brown. Size 
l-1700th. 

T. volvocina. — Form sperical ; colour mostly green, sometimes of a 
brownish hue, but easily distinguished by a red ring on the cii'cum- 
ference of the body ; vesicles may be observed internally, which are 
most probably the digestive sacs, between which a very fine granulated 



148 DESCRIPTION OF {Tolygastrica. 

substance is situated, producing the colour of the body. It is fur- 
nished with a delicate flagellifomi proboscis. The red circle, so re- 
markable a featui-e in this species, always appears to abide in the 
same horizontal pobition, how quickly soever the creatiu-e may be 
revolving on its longitudinal axis. Figm^e 30 represents this crea- 
ture with its proboscis extended; figure 31, another with it retracted ; 
figiu-e 32 is a very young specimen ; and 33, a full grown one, that 
has been pressed between two plates of grass, so as to exhibit the 
lorica broken without destroying any part, except the red circle 
above noticed. Found amongst confervse. Size l-860th. 

Teachxlomon^as cylindrica. Form oblong, approaching to cylin- 
drical; proboscis almost as long as the body. Colour a beautiful 
green; eye red ; ring purple. Size 1 -1000th. 

T. arceolata. Form of lorica globose, surface areolated. 
T. aspera. Figure of lorica similar to preceding, but its surface 
covered with rough points. 

T. granulata. Similar, but its surface very minutely granulated. 
T. loivis. Lorica also globose, with its surface smooth. 
T. pyrwn. Lorica oblong or pear shaped (pyriform) smooth. 
Dujardin, in his family Thecamonadina, includes some genera of 
animalcules not described by Elu'enberg, or otherwise, described 
under different names and a diverse arrangement. They are appended 
here as best agreeing with the Oryptomonadina. 

Genus Phacus. (D.) Body flattened and leaf-like, mostly green, 
and displaying a red speck in front, together with a flagelliform 
filament, and a resistant membranous integument prolonged pos- 
teriorly in the form of a tail. 

This genus comprehends some animalcules, referred by Ehrenberg 
to his genus Euglena, on account of similarity in colour. The differ- 
ence between the two genera is, however, considerable, for in Euglena 
the integument is contractile, and peiTuits of a frequent change ot 
form, whilst in Phacus, on the contrary, the integument appears 
quite wanting in contractility, and the animal invariable in form. 

The enclosing integument of Phacus persists after the death of the 
animal ; after the destruction of the contained green mass, and also 
after the action of various chemical agents, becoming, in the latter 



Cryptomonadina.'] iNFrsoRiAt ANTMAirrLKS. 149 

cases, quite transparent. The motor filament, however, disappears 
with the livdng contents ; but globules of the latter, indeed, remain 
after death. 

The optical character of tlie red speck in the individuals of this 
genus is denied by Dujardin, as also the existence of a mouth, 
stomach sacs, and sexual glands, supposed by Ehrenberg, who has 
described three out of the foiu- species of Phacus, adduced by the 
French naturalist, as specimens of Eucjhna. 

Thus, 1. Pliacus pleuronectes = E.phuronectes. 2. P. longicauda = JE. 
hngicauda. and 3. P. triquetra = E. triquetra. (See Euglena.) 
The new species of which the characters are given is : — 
Phacus tripteris. Body oblong with three longitudiaal plaits meet- 
ing along the axis, rather twisted on the mid rib, with a red speck in 
front and a diaphanous caudiform prolongation behind. Length 
1 -420th, 1-3 12th. 

Genus Ceumentjla. (D.) Body oval, compressed, clothed with a 
resistant integument (testa) obliquely situated, and, as it would seem, 
reticulated, sending out obliquely from a notch in the anterior 
border, a long flagelliform filament. Motion slow. There is no tail 
like prolongation as in Pliams. 

C. texta. Envelope resistant, reticular, filled with a green matter, 
together with vacuolee or hyaline globules, and having a large 
anterior red globule. Length l-520th. Testa persistent after death. 
(P. 21.f. 6.) 

The anterior notch is produced by a sort of overhanging lip. The 
filament is three times longer than the body. 

Genus Diselmis. (D.) Body ovoid or globular, covered by an 
integument, of almost a gelatinous consistence, but not conti'actile, 
and provided with two equal locomotive filaments. 

This genus nearly corresponds to the Chlamidomonas of Ehrenberg, 
placed by him in the family Vohocina, by reason of its apparent self 
division, into two or foiir segments within the testa. Dujardin, on 
the other hand, admits none as Fblvocma which do not exhibit an 
aggregation of perfect individuals within a common envelope. 

The integument of Diselmis is non-resistant, diaphanous, breaking 
up after death, it is sometimes filled with a green substance, ac- 
cording to Ehrenberg, coloured ova, an improbable supposition in 



150 DE9CBIPTI0N OF \Folygastrica. 

Dujardin's opinion, seeing that these beings are sensitive of light 
and, like plants, fix themselves to the lightest part of the containing 
vessel, and disengage gas (oxygen) when exposed to the sun's rays. 
In the green substance are seen granular masses, a disc with en- 
larged border and a red speck. The motor filaments proceed from the 
same opening of the integument, and often form a diaphanous lobe 
projecting from the opening. The red colour seen oftentimes in the 
water of the Mediteranean appears due to Infusoria of this genus. 

DisELMis, vvridis = chlamidomonas puhisculus, (Ehr.) 

D. marina. — Body nearly globular, obtuse, and rounded in front, 
granular within. Length l-1050th. 

This species is larger than D. viridis, more globular, and appa- 
rently deficient of the red speck. Found in stagnant sea water of a 
gi'een colour. 

D. Angusta. — Body pyriform, oblong, appearing to be plaited, and 
tubercular inside, sometimes with an indistinct red speck. Length 
1- 2600th to 1-1 850th. 

D. Dunalii. — Body oval or oblong, often constiicted about the 
middle; colourless when very young, then green, afterwards red, 
two flagelKform filaments longer than the body, seated on a pro- 
jecting and retractile anterior lobe. Interior occupied by coloured 
globules. Discovered by M. Joly, to be the chief cause of the red 
colour of the water of the Mediterranean Sea. 

Genus Anisoi^ema. — Body colourless, oblong, more or less com- 
pressed, having a resistant envelope, giving exit by an opening to 
two filaments, one directed forwards flagelliform, the other trailing 
backwai'ds and retractile ; movement slow. 

In other genera, as in Heteromita, two similarly characterized 
filaments exist, but the present genus is known by its non- contractile 
resistant integument, which is often met with empty and transparent. 
It may be that the Bodo grandis (Ehr.) is allied to this genus as 
well as to Heteromita. 

A. acinus. — Body oblong, depressed, rounded posteriorly narrower 
in front, like the seed of an apple, with an opening close to the apex ; 
movement in a straight line forwards. Length 1-1 300th to 1 -850th. 
In pond water. 

A. sulcata. — Body oval, depressed, with 4-5 longitudinal fuiTOws, 



Volvocina.'] iNFUsoRrAi animalcules. 151 

and au oblique notch in front, from wliich the two filaments proceed ; 
movement vacillating, circular. Length 1-1 300th. The projecting 
filament is three times, and the floating one about twice as long as 
the body. (P. 21. f. 8.) 

Genus Plceotia, (D.) — Body diaphanous, having several ribs or 
longitudinal ridges at the middle, and a circular translucent margin, 
giving the whole a navicular form ; two locomotive filaments proceed 
from one end. 

This distinct form of Infusoria might be mistaken for one of the 
BaciMaria, were not the filaments clearly visible. The characters 
of the filaments are similar to those of Anisonema, one extending 
forwards with an undulatory movement, the other trailing and 
capable of suddenly arresting the movement of the body by its 
adhesion and j»ower of retraction. 

P. vitrea. — Body hyaline, with 3-4 longitudinal salient Hnes at 
the centre, and some granules. Length 1-1 30th; movement slow. 
Found in sea water, kept for two months. (P. 21. f. 10. a.h.) 

Genus Oxyrrhis, (D.) — Body ovoid, oblong, obliquely notched in 
front, and prolonged into a point, several flagelliform filaments pro- 
ceed laterally from the bottom of the fissure. 

The name indicates its elongated apex ; one species only is de- 
scribed ; these Infusoria being but imperfectly known. 

0. marina. — Body colourless ; sub-cylindrical rugose, rounded 
posteriorly. Length 1 -520th. (P. 21. f. 9. a. b.) Found in the 
Mediterranean. 

Family.— VOLVOCIN"A. 

This family derives its name from the rolling motion with which 
the extraordinary creatures belonging to it make their way through 
theii- natural element — the water. The mode in which they self- 
divide, whilst pent up within their loricated vestment, is a curious 
characteristic of the family, and such as would almost warrant the 
supposition that they hold some very near relationship to those re- 
markable creatures termed Zoophytes. They resemble the Monads in 
most particulars relating to their organization. The body is unvarying, 
and except cilia, destitute of appendages. They have several digestive 
sacs, but no true alimentary canal. Whilst propagation by self-division 



152 DK9CEIPTI0N OF [^Poli/gastrica. 

is proceeding, and the young are increasing in size, the siirrotmding 
induvium, which is a distinct lorica, is observed to expand in a cor- 
responding degree, but continues entire until its numerous occupants 
have come to maturity, when it is seen to biu'st, and set them at 
liberty. The animalcules thus set free multiply in the same manner, 
and also by means of ova — in which case the expansive property of 
the lorica comes equally into operation. 

All the genera (excepting, perhaps, Gyges), are provided with 
organs of locomotion, which consist, as with the Monads and Crypto- 
monads, of a single or double flagelliform very delicate proboscis ; and 
hence it is that, when they are in clusters, the entire group appears to 
be ciliated, or beset with hairs. Transparent digestive cells are visible 
in the Volvox glohator and Gonitim pectorale, but in most of the species 
the green ova liide them from our sight. The propagative apparatus 
is evident in all the genera, with the exception of the JJroglena, under 
the form of ova grains, one or two round glands, and a contractile 
bladder. 

The family is disposed into ten genera : five are fui'nished with 
the visual organ, situated at the anterior part of the body, and five 
are without it. In the former, a sensitive system is consequently 
presumed. 

The following is an analysis of the family : — 

f r vibrating j g 

f I proboscis absent ( .» & • 

Lorica box-like< 



•s < 



- . . , I vibratiner 

^ Lonca 8»ngle<; | ^^„,,„^,,i« nrp 

absent 



^^jj ^ i.unca ».ugie^ L proboscis present 



j clusters tabulated or in plates Gonium. 

Lorica double Sj-ncrypta. 

Tail present Synura, 



C f tail present tJroglena. 

Self-division both 

equal and perfect < ( proboscis single Eudorina. 

(no internal globes) tail absent. . \ 

{_ \ proboscis double Cblamidomonas, 

„,,,... , r proboscis single Spheerosira, 

Self-division unequal I ' ° 

(forming internal < 

globes) I proboscis double Volvox. 

There is a tendency in recent observers to refer many, or even all 
of the Volvocina to the vegetable kingdom. Tor instance, Dr. Car- 
penter says, " It is not by any means certain that the Volvocina are 



P4 



Volvocina.] lyrrsoHiAL animalcfles. 153 

not to be transferred to the vegetable kingdom. Their green colour 
leads to the suspicion that they decompose cai'bonic acid, and the 
stomachs described b}^ Ehreuberg in the component Monads, are not 
more distinct than the stomachs which he has represented as existing 
in several other beings, whose vegetable nature is now generally 
admitted. It is considered by Braim, who has paid much attention 
to the development of inferior Alga?, that the Vlovocina are of the 
same type with certain Zoospores, which become composite by fissi- 
parous multiplication." — Principles of Physiology, p. 251. 

Dr. Carpenter's reviewer, in Tlie British and Foreign Medico- Chi- 
rurgical Review, OciobQX, 1851, writes, ''"We have recently seen a 
series of preparations by Mr. Williamson, of Manchester, who has 
paid much attention to the development of the Volvox, which leave 
not the slightest doubt in our minds that the entire hollow sphere is 
oi"iginally composed of cells formed by the multiplication of a single 
one ; and that these cells are of the same essential character with 
those of the inferior Algae generally ; it being a part of their nature 
to secrete a great thickness of pellucid mucilaginous matter around 
the primardial utricle, [The delicate living membrane of the walls of 
cells is so called by Moehl, and is considered of special importance in 
cell-formation.] And thus the green utricles (cells), which are 
originally in close approximation, become separated from each other 
by its intervention, stiU remaining connected, however, by certain 
thread-like prolongations, which Ehrenberg has erroneously described 
as vessels." 

WTiile it is a duty due to the reader to insert the above opinions 
on the Volvocina, my obsei-vations, for more than twenty-five years, 
on these creatures, induce me firmly to believe in their animal 
nature. 

Dujardin, whilst admitting the Volvocina among true animal Infu- 
soria, would effect a difterent distribution of the genera proposed by 
Ehi-enberg. Gyges and Chlamidomonas, would transfer to the Theca- 
monadina, Cryptomonadina, (Ehi-.), inasmuch as they do not present 
an aggregation of individuals enclosed by a common envelope. 
Further, since the visual character of the red specks is not admitted 
by the French naturalist, Eudorina and Pandorina must be combined, 
as also Synura and Uroglena, whilst the genus Sijncrypta is ren- 



154 DEscEiPTioN OF [Polycfasfrica. 

tiered doubtful, and, probably Sphaerosira should be united with the 
Pandorina. 

Genus Gyges. The ring Animalcule. — This genus is characterized 
by being deficient of the eye, tail, and vibrating filiform proboscis. 
The lorica is of a simple box-like form (wrceolm). We know but 
little of the organization, as not even the nuti'itive apparatus has 
been observed ; and were it not that some slight spontaneous motion 
of the body is perceptible, when it is surrounded with a coloured 
fluid, it would seem that all the certain characteristics of an animal 
were wanting. Two species are mentioned by Ehrenberg, both of a 
green coloiu\ and enclosed in a transparent lorica. 

G. gramdum f Volvox gramdmn, 'M..J — Form oval, approaching to 
globular. Body contains a heap of granules within it, of a darkish- 
green coloiu'. Found amongst Lemna and Conferva. A magnified 
representation is given at figiu-e 34. Size l-1150th. 

G. iipartitus. — This species has a body of a ciystaUine gelatinous 
substance, and of nearly a spherical form ; the superficies colourless, 
but its contents yellowish-green. Its body is sometimes divided 
into two, and at others it is a simple sphere. The contents are com- 
posed of numerous homogenous granules, which if the creature be 
an animal, may be considered as the ova, Foimd amongst Conferva. 
Size 1 -480th. 

G. sanguineus. — Body oval, colour red, inclining to crimson, sur- 
rounded by a broad coloiuless ring, representing an enveloping lorica. 
This is a new species discovered by Mr. Shuttleworth in the red 
snow, which fell at the Grimsel, in August, 1839; its motion is 
lively. In Plate 12., group 527, shows several higlily magnified. 
Found with Astasia nivalis and Monas gliscens, among the globules of 
Protococcus nivalis. (See Ml. Phil. Jour, v., xxix., also Dr. Ctihn's 
elaborate Essay.) Length l-1200th to l-300th. 

M. Vogt has described the reproduction of this being as very 
singular. He says, " it gives off from several parts of its body small 
ti-ansparent buds, apparently vesiciilar, and, for the most pai-t, filled 
with granular matter. As they enlarge they become gradually de- 
tached ; sometimes two of equal size, of which one is red and loricated, 
the other colourless, adhere by a very narrow point of attachment, 
which subsequently gives way, and the bud appears as an Infusory 



Volvocina.'\ infusorial animalcules. 155 

animal, like wliat Mr. Sluittloworth has represented in his 7th and 
8th figures, and which approaches Fandorina hijalitm. (Ehr.)" 

M. Vogt adds, that Gyges sanguineus ought not only to be looked 
upon as the type of a new genus, but even of a new family, on 
account of its very peculiar mode of reproduction. 

He foi'ther describes a new Infusorium, as a species of Gyges : — 

Gtges Vogtii. — It occurs as a globular organism, containing in its 
interior from 2 to 5 individuals, enveloped by an apparently siliceous 
lorica. The colour is dark red ; the globules are frequently found 
adherent, and arranged in the form of a cross ; they are also often 
separate. " The small individuals, probably the young, were of a 
clear yellow hue. I could not observe the slightest motion in them." 
On the Animalcules of the Eed ^now. —Bihliotlicque Univers de 
Geneve, May 1841. 

Genus Pandorina. The herry-lihe globe Animalcules. — The cha- 
racteristics of this genus are, its being destitute of eye and tail, but 
provided with the box -like lorica, of a globular shape, and with a 
filiform proboscis. During the process of self-division the internal 
development gives the creatiu-e the appearance of a mulberry. A 
simple proboscis is present in all the species (at least in all the 
European) as the organ of locomotion, &c., and ti'ansparent vesicles, 
seemingly the nuti'itive apparatus, may be observed. There are two 
species only, one green, and the other colourlesss ; the latter, how- 
ever, is a doubtful Fandorina. 

The following characteristics as given by Dujardin, appear more 
clear than those of Ehi-enberg. 

The Fandorina consist of very small green animals, grouped into 
globules imbedded in the interior of a gelatinous mass, diaphanous, 
and ovoid, or globular, in figure. 

Unlike Vohox, iu which the individual animalcules occupy the 
surface, those of the Fandorina are surrounded by a transparent 
sphere, and the mode of the propagation being also different, no 
fonnation of internal globes, and their ultimate escape by rupture of 
the enclosing parent, is seen to occur. 

Fandorina elegans — Endorina elegans. (Ehr.) Dujardin esteeming 
the presence of the red speck (supposed eye) to be insufficient to 
characterize a genus. 

M 2 



156 DBSCEIPTTON OF \ Polygastrica. 

Paniwrtna morum ( Vokox morum, M.) Eody simple or multipartite, 
enclosed within a simple lorica. Colour green ; proboscis twice as 
long as the body. Figure 37 represents a cluster; 36, a single 
animalcule ; and 35, one in which self-division has just commenced. 
Found in water with Lemna and Conferva. Size of individual, 
1-11 50th; ditto cluster, 1-1 20th. Individuals broken from the 
cluster by Ehrenberg have not been above one-third the former 
measurement. 

P, hyalina. Form globular. Found in the Nile with conferva. 
Size 1-5760. 

Genius Gonium. The tablet Animalcules. — The members of this 
genus are especially characterized by being deficient both of eye and 
tail, by having a simple lorica, and by develoj)ing themselves in the 
process of self-division in clusters, of a regular four-cornered tablet 
or plate. The lorica of each individual (as is noticed after separa- 
tion) is nearly round, and resembles a mantle (laeerna), which the 
creature is empowered to cast off, and form anew. In one of the 
species (G. pectorale) two filiform and vibratory proboscides are 
placed at the mouth, as organs of locomotion, &c. ; in the other 
species, these have not been observed. Vesicles are seen within G. 
pectorale, notwithstanding the creatui'e abstains from coloured food ; 
and a red speck (produced probably by inflected light) at the base of 
the proboscides has been perceived by Ehrenberg, which he conceives 
to be the mouth. 

G. pectorale (M). — The form of this animalcule, or more cor- 
rectly, cluster of animalcules, is shown at figs. 38, 40, and 41. It 
consists of sixteen spherical bodies, enclosed -^^-ithin a transparent 
lorica or sheU, and disposed regularly in a quadrangular form, like 
the jewels in the breast- plate of the Jewish High Priest. They are 
all arranged in the same plane. The four centre ones are generally 
larger than those which surround them, and the combined diameters 
of the three smaller balls, are about equal to the two larger centre 
ones to which they are attached ; the external comers are conse- 
quently vacant. As these animalcules swim and revolve in the water, 
they occasionally present a side view to the observer, when the cir- 
cumference of the larger central globules may be seen projecting 
beyond the others. Sometimes the clusters appear irregular ; this 



Volvocina.] iNFrsoRiAL animalcules. 157 

happcnB when tlie larger animalcules have arrived at maturity, and 
some of them have separated from the cluster. When they are all of 
equal diameters, the group divides across the middle, hoth vertically 
and horizontally, and separates into four clusters, each consisting of 
foiu' animalcules. As soon as a cluster has separated, the respective 
animalcules increase in size, and in a short time their surfaces appear 
decussated, and they severally begin to form into regular clusters, 
like the original one to which they belonged. They are of a beau- 
tiful transparent green colour, and in swimming, the globules often 
appear of an ellipsoidal figiLre (see fig. 40) ; their forms, when 
viewed imder the microscope in the usual way, are so simple, and so 
different from animated beings cognizable to unaided vision, that it 
would be difficult to bring our reason to admit of their vitality, were 
not their spontaneous motion clearly ascertained ; and when examined 
under a high magnifying power, with proper illumination and 
management, their structure rendered apparent. Figure 39 shows 
a single free animalcule, with its two proboscides, and figure 42, a 
highly magnified view of another, invested with the lorica. In this 
figure is seen the disposition of the six cords or tubes which connect 
it with the surrounding ones ; also numerous corpuscles within the 
body. A combination of sixteen animalcviles (never more, but some- 
times less) generally forms the square tablet or plate. 

In order to observe the structure of this highly curious and beau- 
tiful creature, considerable adroitness is necessary in the management 
of the microscope, while, a Little indigo, conveyed into the water with 
the point of a camel's hair pencil, will be required to see the whorls 
and currents set in motion around it. It is almost incredible what 
power, comparatively speaking, these minute beings possess, notwith- 
standing the speck they appear to occupy in the scale of creation. 
The cuiTents are produced by the proboscides, two of which, as 
stated above, are situated at the mouth of each individual, so that in 
a tablet or plate, thii-ty-two, in aU — twenty-four placed at the edges, 
and eight standing out fr'om the centre — are brought into action. 

The single animalcules (fig. 39) swim like the Monads, in the 
dii'ection of the longitudinal axis of their bodies, with the mouth 
foremost, but the plates have a variety of movements ; sometimes 



^58 DESCBiPTiox OF \^Polygastrica. 

tliey move quite horizontally, at others vertically, and then again on 
theii- edges, revolving Hke a wheel. A magnifying power of 200 
diameters is siiffieient for general examination ; but to exhibit all the 
structui'es showna in the engTa\ings, four times that power will be 
requii-ed. Foxmd in clear water, salt and fresh, near the surface. 
Discovered by Miiller, in clear water, at Copenhagen, 1 773. Size of 
animalcule from 1 -460th to 1-11 50th ; ditto of tablet, not exceeding 
l-280th. 

Goisixm punctatum. Body composed of green corpuscles, spotted with 
black, and enclosed within a ciystalline lorica. Found amongst con- 
ferva. Size of animalcule 1 -4600th; a tablet of 16, 1-5 70th in 
breadth. 

G. tranquiUum. Body composed of green corpuscles within a crys- 
talline lorica, as shown at figiu-e 43. Size 1 -2880th; a ditto tablet 
of 16, from l-140th to 1 -220th in breadth. Tablet sometimes twice 
as broad as long. 

G. hyaUnmn. Body composed of transparent corpuscles within a 
crystalline shell. Found in stagnant water. Size 1 -300th; ditto 
tablet of 20 to 25, l-6000th in breadth. 

G. ghucum. Body composed of blueish-green corpuscles within a 
crystalline shell. The tablets vary in the number of animalcules — 
namely, from four- to sixty-four. Found in sea Avater. Size 1 -5000th; 
ditto tablet, 1 -500th in diameter. 

Genus Synchypta. The double Iwicatecl globe Animalmles. — This 
genus of the family Yohocina is mainly characterized by its secreting 
or hiding itself (as the name implies) within a second envelope or 
shell. The individuals of the genus are each of them pro\-ided with 
a special lorica of their own, of the fonn of a little shield {smtellum), 
but being of a social character, they have besides a common envelope 
o:- gelatinous mantle (lacerm) into which they retreat or aggregate, 
as occasion may require. They are deficient of both eye and tail, 
but they have a large filiform proboscis, which vibrates, for the pur- 
poses of locomotion, &c. When the animalcules are in a cluster, 
these proboscides give it an appearance of being siurounded with 
hairs. The digestive sacs have not yet been perceived. Self-division 
takes place in a longitudinal direction. 

With this genus Dujardin would identify his Cryptomoms {Tetra-2 
hcena) p. 144. 



Volvorina.] infusokial animalcules. 159 

Synceypta voIvox. Body of an oval form and green colour, with 
whitish rays in the centre. Found generally in water drained 
jEi'om Conferva. Size 1 -2880th; ditto of a clustered globule in its 
crystalline tunic, hardlj^ exceeding l-570th. 

This berry-like cluster of animalcules, when rolling through the 
water, is a beautiful object for the microscope, and, with the aid of a 
little indigo, the numerous currents it creates are readily perceived. 
The usual appearance of the clusters, as viewed under the microscope, 
and amplified 260 diameters, is given at fig. 45. Fig. 44 represents a 
cluster magnified 400 times, and fig. 46 a cluster as viewed by 
Ehrenberg, in its simplest state, wlien about to sever into four. 

Genus Syntjka. TJie ray globe Animalcules are characterized by 
being destitute of the eye, but pro\'idcd with a filiform tail, which is 
attached either to the base of its own lorica, or to the centre of the 
cluster to which it belongs. The general envelope is a gelatinous 
substance of a spherical form, and fitted up into as many compart- 
ments, or cells, as there are individuals in its little community. From 
out of these cells they can severally stretch themselves a considerable 
<iistance, whilst they continue fastened, in the manner before described, 
by the extremely delicate and extensible tail. 

S. uvella. Composed of oblong corpuscles, of a yellow colour ; 
capable of being stretched forth fi-om their cells to three times their 
natural length, by means of the extensible tail. The cluster has the 
form of a mulbeny, and its motion is a rolling one, like that of the 
Volvox glohator. Figiu'e 50 exliibits a cluster magnified, and figure 
51a portion of a cluster, to show the manner in which the tails of 
the animalcules are inserted in the common envelope. This species, 
along with Syncrypta and Uroglena volvox, may often have been con- 
founded with Uvella virescens. Length of body, exclusive of tail, 
1 -700th; diameter of cluster, from l-190th to l-280th. 

Genus TJkoglena. Tlie globe Animalcules, with ray and eye. — This is 
the first genus of the family Volvocina, wliich is distinguished by the 
possession of both the eye and tail. It is also a sort of compound 
animalcule, living in clusters under a common covering or mantle 
(laeerna), which is apportioned into cells for the accommodation of 
the several individuals. Self-division takes place simply and equally 
in these individuals, whilst remaining in their clustering condition. 
Within the mantle they are placed at uniform distances from each 



160 DESCRIPTION OF [Pol^cfastrica. 

otlier, with their tails radiating from the centre, and by means of 
which each animalcule is fixed to the base of its own special en- 
velope. Each one is furnished with a filiform proboscis, which gives 
to the entire group the appearance of being covered with hairs. 
When the creatui'es divide, the mantle or lacema, only enlarges, 
without becoming separated itself. The visual organ is a red speck 
iu the fore part of the body ; the tail is fiiliform, resembling that of 
Vorticella mid Bodo. 

The internal structure of these compound animalcules can be ve- 
rified only with instruments of superior quality, and require con- 
siderable skill in the management of them. This latter qualification 
is so indispensable, that notwithstanding many persons in this 
country possess better microscopes than those employed by Ehren- 
bcrg, the curious organization of these little creatures has hitherto 
eluded their observation. 

Ueoglena vokox. — Body composed of yellow corpuscles of an ob- 
long fonn. Tail extensible from three to six times the length of the 
body, and even more. Cluster mulberry-shaped. There is little 
doubt but that single animalcules of this genus, seen in company 
with the clusters, have often been taken for creatures of a different 
family. Ehrenberg states that he has observed iadividuals with two 
or three eyes, which he conceives to have been a symptom of ap- 
proaching self- division. Eig. 54 gives a magnified representation of 
a globular cluster of these animalcules, and fig. 53 a single one, in 
which the red eye is distinctly visible. Found in turf water. 
Diameter of cluster. l-90th. 

Genus Eudoeina. The globe Animalcule with an eye. — The cha- 
racteristics of this genus are its absence of tail, but possession of the 
eye, which may be distinctly seen, and a simple filifonn vibratory 
proboscis, situated at the mouth, as its organ of locomotion, &c. 
SeU'-di\dsion is also undergone by the individuals simply and equally, 
whilst retaining their dusted position. These little creatures are 
endowed with the power of periodically casting off their globular 
lorica or mantle {lacema) which envelopes the cluster, and exuding 
a new one, like certain animals of the class Annelida. To observe 
the eye a power of 300 diameters must be skilfully employed. 

E. eleyans. — Composed of green corpuscles, of a globular shape, 



Volvocina.] infusoeial aniaialcttles. 161 

never protruding out of their cells from the common envelope. Ej^e 
sparkling red. The clusters which are of an oval or globular form, 
contain generally from 30 to 50 individuals, and never less than 15. 
Motion rotating. Figure 47 is a cluster magnified; it exhibits the 
proboscides extended, and the bodies of the animalcules within the 
lorica. Clusters of these beautiful animalcules ai'e often seen in such 
amazing numbers, along with the Folvox (ilohator and Chlamidomonas 
puktsculus, as to render the water (otherwise colouiiess) of a decided 
green colour, especially towards its edges. They are exceedingly 
delicate, so much so, that it is difficult to preserve them alive for more 
than a day or two : whenever it is attempted to retain them in large 
quantities, the second day will generally exhibit a thick mass of dead 
ones at the bottom of the vessels. "VVTien a few only remain alive, 
if the water be poiu-ed away, and the creatures removed into a vessel 
of clear water, they will live for weeks. Found at Hackney and 
Hampstead ; most abundant in the spring of the year. Diameter of 
cluster 1-1 80th. 

Genus Chlamidomonas. The cuiras Monad Animalcules are cha- 
racterized by being deficient of the tail, but provided with a beau- 
tiful red eye, indicating a sensitive system, and with a double 
fiagelliform proboscis, for the purpose of locomotion, &c. The shell- 
like envelope, which bears the form of a little box (wceolus) encloses 
the creature up to the mouth, and when the young have attained to 
maturity and self-division is to be completed, it bursts, to set 
them at liberty. The lorica is with difficulty perceived upon the 
young ones. 

C. pulmsctdus {Monas pulvisculus, M.) — Body composed of green 
corpuscles, of an oval form, and included within a box-like shell. 
Eye brilliant red, and proboscis double. The clusters are globular, 
and made up of only tliree or four, or at most eight ? Group 52 re- 
presents a single one ; also a cluster about to separate into five 
the latter enclosed in a common envelope. See Diselmis vmdis 
(Duj.) 

These creatures form the larger portion of the green matter which 
colours the water contained in water-butts, ponds, and puddles, in the 
summer and autumn, and especially after a storm. It could hardly 



162 DESCRIPTION OF [Tvli/gastiica. 

fail to have been observed so soon as any of this green water was 
examined under the microscope. 

Wherever these creatures exist in great quantities, multitudes of 
them die ; their bodies, and the envelopes cast off by the living ones, 
are decomposed, gaseous matter is generated, which adhering, causes 
them to rise to the sui'face of the water, forming a green stratum 
upon it. Although the animalcules, and their coverings, when in 
this state, somewhat resemble Uhacece, yet are they easily distin- 
guishable from them by the red speck or eye, wliich is retained for 
a considerable time after death, and the new bodies may be seen 
connected together by means of an intervening membrane, formed 
of dead colourless Infusoria, and the remains of loricae. Size l-550th. 

Genus Spha^ieosiiia. The rudder Animalcules. — The distinguishing 
features of this genus arc its being deficient of the tail, but possessing 
the eye, and a simple filiform rudder-like proboscis. Its method 
of self-di\dding is difterent from that of any of the preceding genera, 
inasmuch as it occiu^s imequally within the envelope, when young- 
clusters are formed at once fi'om the parent ones. This genus differs, 
then, from Pandorina, in having the eye ; from Eudorina, by its un- 
equal mode of self-di-vdsion ; and, from Volvox, by its simple pro- 
boscis. Self-di\ision in these creatures takes place in the longitudinal 
■direction, commenciug in parallel jjlanes, so that lamina are produced 
as with the Gonium. Since, according to Dujardin, but one filament 
exists in Volvox, tliis genus should be set aside as indistinguishable 
from the latter. 

S. volvox, — Body composed of pale green corpuscles, of nearly a 
globular shape, enveloped in a lorica of the mantle form. Eye bright 
red. The cluster resembles a great ball of animalcules, containing 
small compressed clusters within it. Fig. 49 represents a portion of 
the tunic or lorica, highly magnified, so as to shew the difierent forms 
of the creatures located within it ; thus, three single animalcules, 
one mulberry- shaped cluster, and one oblong group may be observed 
within that portion of lorica. Figure 48 represents a large spherical 
cluster. Found in considerable numbers in company with the Volvox 
(jlohator, and often attains its size. Sometimes foimd by itself. 

Genus Volvox. The ylohe Animalcules. — The genus Volvox, which 



Volvocina.'] infusorial animalcules. 103 

is the type of the family Volrochia, was instituted by Linneiis, 
and in-omulgatcd to the world in 1758, in the tenth edition of his 
Systema Naturae. This genus, as fii-st described by him, compre- 
hended the entire race of Infiisona, excepting only eleven of the 
tiibe VorticelJa, which were separated from them, imdcr the deno- 
mination of Hydra, the two species V. glohator and V. chaos con- 
taining all the rest. In his twelfth edition (1766) of the same work, 
he distributes the Infusoria into four genera, \'iz., Vorticella, Volvox, 
Hydra, and Chaos. 

Volvox is characterized by the members aggregating under a trans- 
parent shell-like lorica, of the form of a hollow globe, the creatures 
being distributed over the internal siu'face of it. Each animalcule 
possesses the red eye and a double filiform proboscis, which latter 
protrudes beyond the surface of the lorica, so as to give it the ap- 
pearance (where gi'eat numbers of these creatures are assembled 
to form the globe) of being covered with cilia. The different modes 
of increasing by self-division are especially characteristic of the 
genus. 

Formerly the whole globular mass was regarded as a single warty 
or ciliated animalcule, and the bursting of the globe, whereby a few 
inner globes, which had come to maturity and previously left their 
positions in the lorica, were liberated, was considered as the birth of 
the single animalcule. This theory Ehrenberg clearly proves to 
have been erroneous, and shows that a somewhat deeper research 
is necessary in order to determine the organic relations of the crea- 
ture. The individual animalcules are the little green wart-like 
bodies or specks which are to be seen on the surface of the globe, and 
singly resemble Monads. They have the same relation to their 
globe as the individuals of Gonium pedorale hold to their tabular 
clusters. Each sphere or globe is a hollow cluster, if we may so 
term it, of many hundreds, or even thousands of these living occu- 
pants, and often contain vtithin it other hoUow spheres, similar in 
nature to itself. 

The individuals are protected by a gelatinous lorica or mantle 
(Jacerna), of the form of a bell, which ihej are enabled to leave, 
when full grown. They are connected with their neighbours by 
from three to six filiform cords or tubes. The mouth is situated at 



164 DESCRIPTION OF \_Poli/gast> ica. 

the base of the double proboscis, before mentioned, and indicated by 
a bright spot. The eye, which is placed near the mouth, implies the 
existence of a sensitive system. Dujardin has been unable to detect 
the double proboscis, and the connecting cords as described by 
Ehrenberg, and consequently admits the existence of only one flagelli- 
form filament. 

VoLvox glolator (M). The globe Anmalcules. — The creatures which 
form these clusters are extremely minute. Each cluster is of neai'ly 
a spherical form, and Tvill often contain within its younger clusters, 
of a green colour, and smooth or even surface. ^Tien blue or red 
colouring matter is mixed with the water, strong cuiTcnts may be 
observed under the microscope ai'ound each globe, which, when in 
motion, always proceeds with the same part foremost. 

Eig. 55 represents a large globe with eight smaller ones (termed by 
Ehrenberg, sisters) within it ; each of them has a bright spot, which is 
considered as an opening for the admission of water into the interior. 

Eig. 56 represents a section or piece of a globe, magnified 500 
diameters ; it exhibits five single animalcules and a small cluster of 
six young ones. They are attached to the lorica, and connected 
together by five thread-like bands. Each creatui-e has a double pro- 
boscis and the red eye. 

Eig. 57 represents a single animalcule, separated from its lorica, 
and magnified 2000 diameters. Eound in shallow pools of clear 
water, in spring and summer, at Ilampstead. 

The largest globes measure l-30th of an inch in diameter; the 
smallest free swimming ones l-360th to 1 -240th. Size of a single 
animalcule, 1 -3500th. 

M. Lam'ent describes two kinds of contained reproductive bodies 
in this species, the one green and provided with vibratile cilia, the 
other smaller, consisting of a transparent envelope (shell) which con- 
tains a thick and red globular substance. The fonner he considers to 
be gemmules, the latter oviform bodies, or ova ; which, however, he 
has not yet seen imdergo development. (Institutes de la societe 
PhUomatique, de Paris, 1848.) 

Ehrenberg notified the peculiar occurrence of living Rotatoria 
within the globes of the Vokox glolator. Mr. John Williams has 



Volvorina.] ISTV^OUZXt ANIMALCULES. 165 

commimicated (Trans. Microscopic Soc vol. iii., 1851), an interesting 
observation, confii-ming Ehrcnberg's account. 

"Within the cavity of a large specimen of this species, evidencing 
its nsual vitality, and the ciliary movements on its surface, he 
noticed a very active Rotifer, ■which he believes to have been the 
Notommata parasitica, and which was subsequently accompanied by 
another of the same species, but smaller. He adds, " by the most 
careful examination, no opening could be perceived by which they 
could have been introduced, neither did there appear to have been 
any viscera by which their motions might be impeded, as they swam 
about as freely as fish in a glass-globe, to which, indeed, they bore 
no faint resemblance." 

YoLvox aureus. — Is of a green colour, and nearly globular. The 
large clusters are in the form of a sphere, and the smaller ones 
■nithin them of a golden colour, and smooth surface. Found in rain 
water standing on turf. Diameter of globe l-36th. 

V. stellatus. — Is small, of an angular foitn, and green colour. 
The clusters are subglobose, sometimes oblong, and contain other 
globes within them, of a green colour, and having their surfaces 
tuberculated or stellated. Diameter of globe l-30th. 

Ehrenberg communicated a paper by Werneck, on the Infusoria, 
to the Eoyal Academy of Berlin, and an abstract appeared in the 
monthly report of that society, in which very brief characters of 
several new genera, both of Polygastrica, and of Rotatoria are given — 
two of which ai'e to be inserted in this family Vohocina, as allied to 
the Pandorina. — The first genus is called 

Calia. — Monads imbedded in a gelatinous mass, affixed to plants, 
and not swimming freely ^about. Two species are known, the (cha- 
racters not given.) 

The second genus bears the name of Stephanoma. — Panim'ina with 
a single circular series of animalcules, indi\T.dual corpuscles dividing 
after the manner of Gonium. One species obsei-ved — a genus of a 
peculiar form exhibiting a circlet of spherules, connected as a wreath. 
(Monatsbericht der Konigl Preuss. Akademie der "Wissens. Chaften 
Zu Berlin. November 1841, p. 377.) 



166 DESCRIPTION OF [Polycfastrica. 



Family.— VIBRIONIA. 

The animalcules of this family are distinctly or apparently poly- 
gastric, but without a true alimentary canal, and, like the Monadina, 
are incapable of changing the form of their body. They have neither 
appendages or shell-like covering. They are associated or linked 
together in thi-ead-like chains, fonned by their imperfect transverse 
self-division. Considering how much we know of the organization 
of the family Monadina, we are comparatively far behind in in- 
formation respecting the Vibrmiia, and were it not that the cause of 
our ignorance is manifestly attributable to the exceeding minuteness 
of the individual animalcules, we might be justified in imagining 
their stiaicture to be more simple than in all probability it really is. 
The filiform and very delicate threads in which they occur, are not, as 
we have said, scpai-ate animalcules, but chain-like clusters, whose 
almost imperceptible links are themselves (at fii'st) single creatures. 
The reasons to be assigned for arriving at tliis conclusion, are, that 
the clusters or chains have never any detonninate length, or number 
of members forming them, and that they are sometimes so short as to 
be made up of not more than two or three individuals, and only dis- 
tinguishable from Monas termo and M. crepusculum by their mode of 
union, and peculiar, though not easily characterized movements. 
Hence all their organic relationships are to be sought for in these 
minute portions of the chain. To discover these is a task not to be 
fully accomplished, even "with the greatest assiduity, coupled with the 
most effective optical means which we at present possess. The 
traces of organization in the members of this family are so few, and 
those so indefinite, that a question might ai'ise whether or not they 
are to be considered as belonging to the animal portion of the creation. 
The answer to this is, that they possess a very powerful writhing, 
and evidently voluntary form of locomotion ; and in one genus 
{Bacterium), a single vibratory proboscis is present as the organ of 
motion. In it the individual forms are strung more slightly together, 
the filiform cluster not being able to exert the writhing movement 
peen in the true Vibriones, a direct movement in swimming being alone 



llhrioniii'] iXFUsoRiii. axtmalcules. 167 

practicable. In Spirillum the constrictions or ai-ticulations are 
oblique, so that increase in length by di\'ision engenders a spiral 
chain . 

The animals of this family "ai'e (says Dujardin,) the first Infusoria 
wliich present themselves in all infusions, and those which from 
their extreme smaUness and the imperfection of our means of obser- 
vation must be considered the most simple ; .... and it is only 
their more or less active movements which lead to their being 
regarded as animals. I have been sometimes induced to believe that 
a flagelliform filament, analagous to that of Monads, or rather a spiral 
undulating one, exists ; causing the peculiar mode of locomotion. Is 
the Bacterium ^/77o<;«fore, described by Elu'enberg as having a proboscis 
a ti'ue Vibrio ? 

AU that can be Avith certainty predicated respecting their organi- 
zation is that they are contractile, and propagate by spontaneous 
fission, often imperfect, and hence giving rise to a greater or less 
increase in length. 

The Vihrionia are developed with extreme rapidity in all liquids 
containing changed or decomposed organic substances. 

Wagner and Leuckliart, speaking of the sort of motion in cyHn- 
diical-shaped spermatozoa, make this general remark, " They are 
principally limited to a bow-shaped curvatiu^e, similar to the motion 
of the Vihrionia which, like the Ilonadina, belong to the vegetable 
kingdom, and may undergo a fiu'ther development into fibrous fungi. 
( Cyclopcedia Anatomy Art. Semen, p. 503. y 

Dr. Burnett, of JSTew York, has written a paper to prove that the 
Vihrionia are plants. He says the only assignable reason for con- 
sidering them animals is their supposed voluntary motion ; a suppo- 
sition to which he is opposed. As evidence of their plant-nature, 
he adduces the fact of their branching, like Algae ; an occurrence 
particularly observable in Sjjirillum. He believes the smaller are 
only the younger forms of the larger species ; and that they propa- 
gate by gemmation, and not by fission only, as Ehrenberg states. 

Concerning the so-caUed voluntary motion of the Vihrionia, Dr. 
Burnett remarks : " It is because the motions have a kind of directive 
character that they have been called vohintary ; a condition neces- 
sarily implying a dii'ect act of perception on the part of the form 



IQQ DESCRIPTION OF [Polj/gastrica. 

moved, and one wliich at once sti-ikes ub as untenable. Such motions 
ac^ain Ire partaken in by spei-matozoa and vegetable cells, and cannot 
be adduced as signs of animaUty. I know nothing more confirmatory 
of this than the behavioui' of these forms when subjected to certain 
re-ao-cnts" Dr. B. then assumes that beings endowed "with aiii- 
mahty, or a sepai-ate individual entity, yield more or less to the 
influence of electrical and other agents, which appear to act without 
any disorganizing process." He next states that he found '' electnca 
shocks sufficient to kill small animals, had no effect on theii' ( Vibnoma) 
movements. But the application of acids, or other agents acting on 
the cell-structui^e, soon caused them to cease." Viewing them as 
Algeous plants throws light on several common phenomena. One m 
particular is. that the Vihrionia should ahnost invariably be found 
in infusions and liquids that contain other alg^, and especiaUy the 
common Forula. For I do not remember ever to have seen the 
Fonda without Vibrioniar -{Proceedings of the American AsmiaUon 
for the Advancement of Science, 1850.; 

This famHy is distributed by Ehi^enberg as follows :— 

f T u -u^r. ... Bacterium. 

Articulated threads (cluster.). I Mexible 

Straight, the divisions being <. 

rectangular and transverse ^ flexible, like a snake Vibrio. 

Flexible Spirochoeta. 

Articulated threads spirally twisted 
(like a bell-spring or coik-screNv j the 
transverse divisions being oblique 



Inflexible < 



•with a cvlindrlcally , 

extended \ Spirillum, 

spiral form ) 

with a disc-like i 
compressed spiral / SpirocUscus. 
form ' 



On this subdivirion of the famUy nin...™ into genera and BpecMS, 
Dr. Bm-nctt has the following observations: "when we come to 
organisms as mirmte as these, the distinguishing eharactensties of 
genera and speeies beeonie too obseui-e and equivoeal to have niueh 
valne. and the best niieroseopists have arrived at the eonelnsion that 
Lh distinctions are too refined, and will not bear the test of ex- 

^"' The genns TOm-the simplest, I regard as the first appearance 
of the young Alpe. existing then as the smallest cells, arranged m 
linear series. The genera S^r^lm and BacUrnm, composed of 



Vihrionia.l infusoeial ANiMALcrLES. 1(J9 

larger forms, and of a more fine and solid structure, represent the 
more advanced fonns, and us all Algae, as they advance in size, tend 
to consolidate into mycodermous forms, losing much of their primi- 
tive cell-structure, so these two genera appear to have lost their old 
beaded type. As for the two remaining genera, Spirochoeta and 
Spirodiscus, but little is positively known. They scarcely appear to 
belong to the other forms of this family, and as Ehrenberg liimself 
has expressed a doubt upon the subject, one may as well omit a 
further notice. Therefore, in a structural point of view, the species 
of this family seem to be only Algoe at diifei-ent stages of growth." 

Genus BACXEEnrM. The j'omted-wand Animalctdes are distinguished 
by being connected together in a thread-like chain, of an inflexible 
nature, and by propagating by transverse self-division. 

The three species known to us are colourless, and extremely 
minute. Ehrenberg remarks, " that only one of the species has been 
satisfactorily determined, and that their organic relations are alto- 
gether so occult, that our judgment respecting them must unavoidably 
be left in a fluctuating state." In B. triloculare, organization is dis- 
coverable to the extent of a vibratory proboscis, a granulated mass 
within the body of the creature, and a faculty of spontaneous 
division. The only animal endowment common to all the species is 
an active and voluntary power of locomotion. 

A magnifying power below 500 times linear will not exhibit the 
divisions or transverse lines displaying the individuals or links of 
■which the wand-like cluster is composed. I have generally met with 
Bacterium around decomposed vegetable matter, on the surface of 
water containing chara, &c. 

B. triloculare. Chain consists of from two to five animalcules, of 
an oval form, developed in short cylinders, generally about thi'ce 
times as long as their diameter, and marked with transverse lines. 
Ehrenberg has observed not more than five links together nor less 
than two, a single animalcule never having faUen under his notice. 
By throwing a little colouring matter into the water, an evident 
vibration may be perceived in it, near the anterior portion of the 
animalcule; and upon a very close inspection, a simple filiform, 
though short proboscis, is seen, which, in the larger specimens, is 
one-third the length of the bodj', and in the smaller, one half. The 

N 



IjQ DESCEitTiON OF \^Polijgustrica 

motion of this creature is tremulous, or slowly revolving upon its 
longitudinal axis. Found in the water of bogs. Length of cluster, 
l-4800th to l-2304th ; ditto of link, or single animalcule, 1-1 1520th. 
Group 58 represents several of them ; two towards the right are 
magnified 1000, the others 290 diameters. 

Bactemum enehelys. Chain composed of somewhat indistinct animal- 
cules, of an oval form, developed in smaller cylinders than the pre- 
ceding, transverse lines faintly marked, colourless. Found in river 
water. Length of cluster, 1-2 8 80th. 

B. punctum. Chain composed of indistinct animalcules colourless, 
approaching to a globular form, much smaUer than the preceding 
species, and developed in cylinders, transverse lines faintly marked. 
Found in water wherein bread has been steeped. Length of cluster, 

1-4032. 

The following species is added by Dujardin : 
B. catemU. (D.) Filiform, cylindrical. Length of individuals, 
l-8600th to l-6500th, 3, 4, or 5 axe united together, forming a chain 
l-1300th in length. 

Genus Yibkio. The tremUing Ammaleules. -Thi^ genus is charac- 
terisedby the animalcules being connected together in filifoi-m chams, 
of a flexible nature, resembling the body of a snake. These chams, 
^s akeady remarked, are produced thi'ough incomplete self-division. 
The difficulty of ascertaining the internal organization of this genus 
has not, as yet, been surmoimted, although it is fair to presume that 
there is notHng of a tubular character, or intestinal canal, running 
alono- ^thin their fihform bodies, similar to that of the vinegar 
eels^r it would most probably have been demonstrated by the 
aid of coloiu-ed food; for aline is much more easily distinguished 
than a point. Fhrenberg supposes, that each link in the cham 
is a closed, round. Monad-like body, having a nutritive apparalnis 
of a polygastric description. v i • i 

V lineola {Bacterium termo, I)uj.)-Qlu^i^r, a minute cyhndiical 
and sli-htly flexible wand, rounded at both ends, and made up of 
bodies Somewhat indistinct, but of nearly globular form, and coloui- 
less Commonly foimd in vegetable infusions, especially roimd the 
stalks of flowers in glasses Length of wand, from l-3600th to 
l-200th. Thickness 1 -3600th. 



Vibrionia.'} INFUSORIAI ANIMALCUrES. 171 

ViBETO tremnlans. Wand short ; stouter, yet more flexible, than the 
preceding ; articulations of an oblong form, but not distinct, . Found 
in water emitting a disagreeable odoiu-. Length of wand, 1 -3600th. 

V. suitilis. AYand slender and elongated ; colom-lcss ; articulations 
distinct ; motion slightlj^ vibrating, ^^'ithout varying the direct posi- 
tion of the articulations. Length 1 -450th. Thickness 1 -24000th. 

V. rupda ( Vibrio rcffula, M.) Wand elongated, and stouter than 
the preceding ; articulations distinct, and colourless ; motion brisk 
and serpentine ; common in infusions. Length 1 -580th. Thickness 
1 -12000th. 

V. prolifer. Wand short, stout, and coloiu'less ; articulations dis- 
tinct. Motion slow and tortuous. Foimd in infusions where mildew 
is present. Length 1 -1100th. 

V. lacillus, (M.) Wand stout, elongated, and transparent ; articu- 
lations sometimes distinct, at others, only so when taken from the 
water and diied ; motion serpentine ; form sti-aight when quiescent. 
Group 59, represents thi-ee wand-like clusters. Found in vegetable 
infusions in fetid water. Length 1 -200th. Thickness 1-1 7200th. 

V. synxanthus. Wands (Bacilli) very fine and short, rather flexuose, 
rarely, if more than five segments (individuals) yellow and minute. 
Size of each animalcule 1-70, 000th to 1 -52000th. Found in decom- 
posing cow's-milk producing a yellow tint. 

V. syncyanus. Wands very slender and short, somewhat flexuose, 
of seldom more than five segments, very small, and of a blue colour. 
Size l-78,000th to l-52,000th. Also found in cow's-milk, and pro- 
ducing a decided blue shade. 

The following species are fi-om Dujardin's work : — 

V. serjmis (M.) Body very long, fUiform, undulating, generally 
pursuing a rectilinear coiu'se, with fi'om ten to fifteen bends in its 
length. Length 1 -1050th. 

V. amliguus. Under this name, Dujardin describes a vibrio with 
stiff filiform joints like those of V. hacilhis, but much larger. Four 
or five, or even more, were articulated together ; owing to the large 
dimensions, each joint could be seen composed of a resistant tube, in 
which a glutinous substance was collected more or less closely. More- 
over, a bifui'cation at the exti'emity of a joint was sometimes seen to 
occur, giving rise to two series, more or less extended. 

N 2 



172 DESCRIPTION OF IPoIt/c^astrtca. 

Such obsei'vations tend to render the aniinality, not only of thiii 
vibrio doubtful, but also of the similar but smaller V. Bacillus a 
matter of uncertainty. 

Genus SriEOCHOETA. The twisting Animalcules. — This genus is 
characterized by its members being developed in filiform and flexible 
chains, of a spiral description, lengthening by the imperfect or in- 
complete mode of self- division. The details of then' organization 
are at present unknown to us. Dujardin does not admit this as a 
genus distinguishable from Spirillum. 

S. plicatilis (V. serpens, M.) Chain constituted of very delicate 
bodies, of nearly globular shape, connected together in a long filiform 
spiral, having numerous and closely aiTanged coils; colourless. Group 
62 shows three clusters. Found at Tilbury Fort. Length of chain 
l-170th to l-440th. Thickness l-12000th. 

Genus SpiEiLLtrM. The cylinder spiral Animalcules. — This genus is 
characterized by its members developing themselves in tortuous 
chains, or inflexible and cylindrical spu-als. These are elongated in 
the same manner as before described, by the iucomplete self-division 
of the creatures, which takes place in an oblique direction. Their 
brisk, energetic, and voluntary motion, and the increase of the chain 
by division, are the only animal properties which have been hitherto 
observed as characteri2dng the creatures. 

S. tenue. Spiral consists of three or four coils, constituted of very 
slender, slightly bent, and colourless fibres ; articulations distinct. 
Found in vegetable infusions. Length about 1 -900th. Thickness 
1 -1200th. 

S. undula (V. undula M.) Spiral consists of one and half turns; 
fibres short, stout, and much bent ; articulations distinct ; colourless ; 
when dry, the articulations are more distinct. Ehrenberg remarks, 
that the fonn of this species is like a bow; and Miiller, that it 
resembles the letter V. Fig. 61 represents a group magnified 800 
diameters ; the dotted lines indicates the impression left on the 
eye when the creature is in motion. Found in stagnant water 
having a mildew scent. Length about 1-1 500th. Thickness 
l-20,000th. 

S. volutans {Vihrio spirillum, M.) Consists of three, four, or more 
coils ; fibres verj' tortuous, long, and stoixt ; articulations distinct ; 



1'iiriofiia] infusorial animalcules. 173 

colourless. Found in vegetable infusions. Length of spii-al l-2200tli 
to 1 -500th. Thickness 1- 14400th. 

This creature strongly resembles the minute Algoe discovered by- 
Mr. Thompson, as producing the various colours wliich the Ballydi'ian 
Lake assiunes, and which he has described under the name of 
Anahaina spiralis, in vol. v. of the Ann. Nat. Hist. ; his figures 
resemble group 61. The genus is characterized as consisting of an 
extremely minute moniliform thread, of a rich green colour, and 
regularly spii-al, like a corkscrew; globules of equal size throughout." 
In decomposing, it is at first blue and then ferruginous ; each glo- 
bule ajipeared to consist of a number of granules enveloped in a 
hyaline membrane. Length of a single coil about 1 -200th 

S. Iryozoon. CoUs consist of a thick body, with a delicate wavy 
hair-like proboscis. These creatures, found in the reproductive 
organs of plants, are called by their discoverer. Dr. TJnger, of Gratz, 
spermatic animalcules. That distinguished botanist has described 
them in detail in the Regensburger Botan. Fidung. Flora. 1 834 ; and 
also in the 18th vol. of the Nova Acta NaturcB cur Bonn, 1838. As 
a condensed view of this subject is given by Dr. Meyen in the 
Jakresbericht (a work, the like of which England does not possess), 
for 1838, I shall here insert the ti'anslation I have had made, with 
the dra^viIlgs Dr. linger kindly sent me for this work. 

"The spermatic animalcules in Sphagnum consist, according to 
the earlier observations of Unger, of a thick body, and a thin filiform 
tail ; in motion, this tail being anterior, he holds it analogous to the 
proboscis of many of the Infusoria. No tnie active motion of the 
body itself has been observed by Unger ; but he distinguishes be- 
tween the mere locomotive and the rotatory movements of the whole 
animalcule. The simplest motion takes place in a spiral direction ; 
and, if the proboscis is contracted, the movement is simply rotatory. 
During locomotion of the creature, which proceeds in a spiral 
manner, Unger saw from one to three revolutions of the body in a 
second ; and during rotation, he noticed the point of the proboscis to 
be in a continual state of tremor. Unger endeavours to show that 
the sjjermatie animalcules of the mosses arc analogous to the spermatic 
animalcules of animal organisms, although we find certain things in 
the former not seen in the latter, and which may somewhat embarrass 



174 DESCEirxiON OF {^Polygastrica. 

their classification, tlic chief of which are the steadiness of the 
spu-al direction of the proboscis, and their manner of movement. 
Lately, Unger has found spermatic animalcules in the anthcridia of 
Polytrichum j'uniperinum, P. commune, P. urnigerum, and P. alpestre, as 
well as in Funaria hygrometrica, Bryum mspidatum, and B. punc- 
tatum, &c., &c. In Polytrichum commune, the animalcules are found 
in very small hexahedral cells -with rounded comers. Generally, 
whilst in the cells they are motionless ; in some, however, a tremu- 
lous motion of the thin proboscis, and in others, again, a rotatory 
motion, interrupted at inteiTals, was seen. The diameter of the deK- 
cate proboscis is 0.004th of an inch. In a few animalcules, isolated 
from their cells, a trembling oscillating motion of the proboscis was 
seen." 

To these particidars, I may add a remark of Dr. linger, quoted in 
the Ann. des Sciences Nat., which induced me to introduce the 
species: — 

"The doubts," says linger, "which remain concerning some of 
the organs of the animalcules of mosses, further increase the incer- 
titude as to their situation in the scale of beings. From all circimi- 
stances, I am incHncd to place them in the genus Spirillum of 
Ehrenberg, and to describe them under the name of Sjnrillum 
hryozoon." 

On mentioning these pai-ticulars to Mr. Yarlcy, he refeiTed me to 
his article on Chara, in the 50th vol. Trans. Soc. Arts, from which is 
extracted the following : — 

"Prom these cells" (in the globule in the axil of the Chara) 
" grow out numerous clusters of long vessels, possessing the most 
extraordinary features yet observed. "When these are first protruded 
from the globiile, if not quite mature enough, theii' appearance is 
like dense or strongly-marked ringed vessels, the divisions of which, 
or their contents, soon begin to appear irregular. * * * After a wliile, 
these ciuis \vithin the divisions become agitated ; some shake, or 
vibrate about; others revolve in their confined places, and many 
come out, tlnxs showing that they are spirals of two or three curls; 
these with an agitated motion swim about * * * Now the field of 
view appetu's filled with life ; great numbers of these spirals are 
st'cu agitated and moving in all directions ; they all have u diicctile 



Vibrionia.'] infusorial aisttmalcules. 1.75 

force, one end going foremost, and never the other ; raanj^ stray a 
great way out of the field : these, by getting clear of each other, are 
the best to observe ; they do not quite keep their foi-m as a stiff 
spiral, but their foremost end seems to lash about, and to many are 
seen attached almost invisible but very long fibres. These fibres 
were in quick undulations, Avhich ran in waves from the spiral to 
their farthest end. It appears that these fibres cause many of the 
spirals to entangle together, and thus bring them sooner to a state of 
rest; thcivfore, the separate ones were best to observe." 

The most recent observations on these creatures, found in the 
anthers of the C/mra vulgaris and hhjnda, are by M. Thuret, given 
to the Annal. des Sciences, a valuable translation of which will be 
foimd in the Annals of Natural History, vol. vii., from which I 
exti-act the following : — 

" The portion of their body most apparent, appeared like a spirally- 
rolled thread, of thi'ee to five curves. They were slightly tinged 
with green, similar to the nuclei ; and like them, turned brown 
with iodine, their two extremities becoming more or less coloured 
(according to the quantity of iodine employed) than the rest of the 
body, thus indicating a difference of nature in these portions. At 
a little distance behind one extremity proceed two bristles, or ten- 
tacula, of excessive tenuity, which the animalcule incessantly agitates 
with great rapidity. These are probably organs of locomotion, 
similar to the filiform prolongation, found in the Infusoria without 
cilia. Indeed, the part thus furnished with tentacula moves fore- 
most, drawing after it the rest of the body, which turns about in the 
water, but always preserves its turriculate form. The incessant agi- 
tation of these tentacula, and their extreme tenuity, rendered it im- 
possible to obsei-ve them in the Living animal ; recourse was therefore 
had to the evaporation of the water, or to the application of a slight 
tincture of iodine, when the animalcules ceased, their motions 
became contracted, and their spiral unroUed, when the tentacula 
were rendered very distinct, from their brown colour. These 
tentacula were frequently observed to be soldered together, fi'om 
one-half to one-thii'd of theii- length upwards, but others were also 
noticed to be cntirelj^ separated down to their bases. A swelling 



176 DESCRIPTION OF [Poli/ffastrica. 

similar to that in the flexm-e of the body was perceived in their 
cui'ves. 

" Ammonia arrested their motions, and contracted the body gra- 
dually into a small oval mass, but did not produce the phenomenon 
of decomposition by solution fdijffluencej, so remarkable in the Infu- 
soria. A very weak solution of hydrochloric acid in water violently 
contracted them into a shapeless mass." 

In Plate XII., fig. 519, 520, and 521, represent the spermatozoa 
found in Pohjtrichum commune, the first figure exhibiting them 
enclosed in the cellules, and the others swimming freely. Figures 
522 to 524, are taken from Marcliantia polymorpJia. Figure 525 is 
from Sphagnum eapilUfolium. All the above are represented mag- 
nified 1000 diameters. Figures 526 to 528 are from the Cha/ra 
vulgaris, and figures 529 to 531 from. Jungerman7tia pinguis, as figured 
in Meyen's work, entitled JVeues System der Ffiamen. 

On this subject of vegetable spermatozoa, Schleiden, in his recent 
work on the " Principles of Botany," remarks, " The doctrine of 
vegetable spermatozoa is now I hope gradually dying away. The 
granules (generally starch), taken fi-om spermatozoa, have indeed 
lost their life in Fi-itsche's tincture of iodine, since their evidently, 
purely, physical, molecular movement remained undestroyed. 

" .... Fritsche has completely settled the matter, and every 
unprejudiced observer may convince himself with ease, of the com- 
pletely untenable nature of the wonders formerly spun out, especially 
by Meyen. The confirmatory observations of Nageli on this point 
are also of great value." 

Again, he says, "as to the mechanism of the motion, we know just 
as little as we do of that of the moving cilia ; of the cause of motion, 
of the motive power, just as much as that of the contraction of the 
primitive muscular fibre, of the motion of animal spermatic filaments, 
and of the vibratile cilia on animal and vegetable cells ; that is to 
say, absolutely nothing." 

Further, in reference to the motion of the so-called spermatozoa, 
Schleiden observes — " There can be no question as to its not being a 
vital phenomenon, because the motions continue even in the alcohoKc 
tincture of iodine (an absolute poison for all vegetable and animal 



Vibrionia ] infusorial ANlMALcriES. 177 

life), of wliicli one may readily convince himself, and wliicli Tritschc 
has, with his well knuwn accuracy, shown to be the case in a great 
number of plants." (Sec Dr. Lancaster's translation, p. 99 and 359.) 
This assertion of Schleiden, that tincture of iodine is an absolute 
poison for aU animal and vegetable life, must be received with re- 
serve, since animalcular life has been knoAvn to exist in agents, such 
as strong acids, and mineral poisons, which, a fHori would appear 
quite as inimical to it as tincture of iodine ; and even m i n ute animals 

the acari, of far higher organization than the polygastrica, have 

been stated to preserve life in strong acetic acid. 

Before dismissing this subject, it may be useful to append some 
observations made by "Wagner and Leuckhart, in their elaborate and 
original article before quoted. 

Having remarked that up to the most recent period, the so-named 
spermatozoa of animals have been considered as independent animal 
organisms, or parasitical animals, and classified among the Infusoria, 
the authors proceed to say that such assumption is perfectly irrecon- 
cileable with our present knowledge of these bodies, based as it is, 
principally upon the discoveries of E. Wagner, Von Siebold and 
KoUiker. With our present means of scientific diagnosis it can be 
proved that the formations in. qiiestion are mere elementary consti- 
tuents of the animal organization like the ova ; constituents equally 
as necessary for the spermatic fluid as the blood globules are for the 
blood. The remarkable phenomena of the life of spermatozoa are 
quite analagous to those phenomena of motion, observable not only in 
animal formations, but also in vegetable structiu'es, as, for instance, 
in the spores of algae, and of the lower species of fungi, in the so- 
termed vibrmies which grow out into the fibres of the conferva called 
Hygrocrocis.''^ 

Again, " an unprejudiced observation will prove that the sperma- 
tozoa are every where void of a special organization, and consist of 
an uniform homogenous substance, which exhibits, when examined 
by the microscope, a yellow amber-like glitter. The opinion of an 
internal organization of the developed animal elements was not a 
little supported by the various remarkable phenomena of motion 
which were frequently perceived in them. In former times, when 
people had no idea of the existence and extent of the so-called auto- 



178 DESCEiPTioN OF {Folygastnca. 

matic phenomena of motions which take place'without the intervention 
or influence of the nervous system, when nothing was known of the 
motion, very similar to a vohmtary one which exists even in plants j 
this movement was certainly calculated to place the independent 
animal nature of the spermatozoa beyond a doubt. But it is different 
now. We know that motion is not an exclusive attribute of animals, 
and that an inference respecting the animal nature of the formations 
in question, however similar the motion observed in them may be 
to that of animal organizations, is a very unsafe and venturesome one. 

We know that certain elementary constituents, animal as well as 
vegetable, possess a power of movement, and that they retain it for 
some time after having been separated from the organisms to which 
they belonged. We only need here remind our readers of the so- 
caUed ciliated epitheUum, the several ceUs of which swim about in 
the fluid surrotmding them, and which, when in this state, have not 
imfrequently, and that even qiiite recently, been considered as inde- 
pendent animals ; how, further, the spores of the algae possess motion 
by the aid of a ciliated investment, or of a single or manifold 
long whip-like fibre, until they eventually become fixed and develope 
themselves into a new plant. Such spores as these may be found 
described and illustrated in the well known magnificent work of 
Ehrenberg, classified as Infusoria, under the groups of Monadina, 
Volvocina, &c. 

Under such circumstances we may consider ourselves perfectly 
justified in declaring every attempt to prove the parasitic nature of 
the spermatozoa by the characteristic of their peculiar motion, as 
futile and inadmissable." 

Genus Spieodisctts. — The dish-spiral Animalcules are characterized 
by developing themselves, through an imperfect self-division taking 
place in an oblique direction, in elongated chains, or into inflexible 
spirals, of a disc-like figure. Its organization is so little known that 
Elu-enberg considers the genus as by no means satisfactorily deter- 
mined. 

S. fulvus. — A lenticular spiral, of a yellowish brown colour. Arti- 
culation indistinct. Group 62 represents three spirals, magnified 
200 diameters. Found amongst conferva. Ereadth of spirall- 1200th. 



Closterina.'] infusceial animalcules. 179 



Family— CLOSTERINA. 

The animalcules of this family arc polygastric, or to all appear- 
ances 80, and destitute of an alimentary canal. Then- bodies are 
unvarjdng in form, and without any appendages. Like the Crypto- 
monadina, they are enclosed witMn loricated envelopes, which simul- 
taneously with theii" bodies, undergo incomplete self-division, so as 
to form polypi-shaped clusters, of a wand, thread, or fusiform figure. 
Each individual is fm-nished with a papilla, or sort of nipple, wliich 
protrudes, but very slightly, through an aperture in the shell, and 
serves as an organ of locomotion. 

The envelope, or lorica, investing these creatures, is of the form of 
a little pitcher (urceolm), and either of a yellowish colom", or coloui-- 
less. In many of the species it is open at both ends. The animalcule 
itself is a very delicate mucous body, clear as crystal, and often con- 
tains -nithin it vesicles and green granules, which latter are most 
probably ova. The locomotive organs appear to be veiy short, 
slender, and conical-shaped papilloe or nipples, of a transparent hue, 
placed just within the opening of the lorica, and but very slightly 
protuding from it. The small vesicles observable among the green ova 
are, according to Ehi'enberg, belong to the polygastric apparatus. 

As several eminent botanists have considered the various species 
included in this family, and the family Bacillaria, as belonging to 
the vegetable, and not to the animal kingdom, I have transferred the 
generic and specific descrij^tions to Section 1 of the family Bacillaria. 

It should be borne in mind, in treating of this matter, that the 
descriptive characters of the Closterina, and the illustrative drawings 
of them, will not be in the least reduced in value or interest, whether 
these organisms are considered as forming a portion of the animal or 
vegetable creation. 

To the microscopist the members of this family possess much in- 
terest, arising from the cu'culation of the particles within the shell 
neai' the ends, and also along the sides. For these observations an 



180 DESCEiPTlON OF [Pol^/ffastricu. 

am2)lifying power of 400 diameters, is required ; but even a single 
lens of that power will shew it. 

I may remark here that many observers with the microscope, and 
even acute naturalists, have been unable to see the circulation in 
these creatures, and I have for many years past received queries on 
this subject ; even Mr. Ralfs, in his beautiful work on British Desmi- 
diece, had not seen it until shewn by Mr. Brawerbank. This is 
the more remarkable, as a good single equi convex lens ■will exhibit 
it. The difficulty appears to me to arise from the want of proper 
adjustment of the focus. The best method is carefully to adjust the 
focus of the microscope for a distinct vision of the outer shell, then to 
bring the object a little within the focus and the circulation, will be 
seen ; the vision of the shell being indistinct. For observations on 
the cii'culation, stops or diaphi'agms, under the stage, may often be em- 
ployed with advantage ; a large angle of apertui-e not being essential. 
The circulation in the Closterina resembles the diffused circulation in the 
aquatic lavae of insects, or that seen at the joints of the legs of spiders . 

This phenomenon is sometimes compared with the cyclosis in the 
Char a and other plants. 

Elu'enberg gives the following reasons for placing the Closterina in 
the animal kingdom : — First, they exert a voluntary motion, as 
shewn fii-st by Corti. Secondly, they have apertures at their extre- 
mities, as noticed by himself. Thirdly, they have projecting organs 
near these apertures, perpetually in motion. Foui'thly, they increase 
and multiply by a transverse self-division, as observed by Miiller. 
These four endowments Ehrenberg considers as being abundantly 
sufficient to detennine the real nature of the Closterina, inasmuch as 
whereevcr voluntaiy motion, an aperture or mouth (feet), and spon- 
taneous division exist, you may conclude at once, ivithout ivaiting to 
Me the creature eat, that the supposed plant is indeed an animal. 

Since the above was written, some interesting obsen'ations have 
appeared in !N^o. xxxiii. of the Annals of Natural History, by Mr. 
Dakymple, from which I select the following ; my intention in this 
work being not to confine it to my own views, but also to record 
those of others, belics-ing that, by so doing, I shall best serve the 
public, and advance this science. 

Mi'. D. describes the Closteriiim as consisting of " a green gelatinous 



CJosterina.'] INPUSOP.IAL animalcules. ISl 

and granular body, infosted by a highly elastic and conh"actilc 
membrane, which is attached by variable points to a hard siliceons 
shell." This lorica, Mr. C. Varley states, will resist even the action 
of boiling nitric acid. " The form of Closterium is spindle-shaped or 
crescentic, the shell consisting of two horns, tapering off more or 
less to the extremities, and united at the central ti'ansverse line, 
constituting a perfectly syramctrical exterior. At the extremit)^ of 
each horn is an opening in the shell, which, however, is closed "wdthin 
by the membranous envelope — wanting, however, in some specimens. 
Within the shell, and at the extremity of the green body is a trans- 
parent chamber, containing a variable number of active molecules, 
measuring from the 20,000th to the 40,000th of an inch ; these mole- 
cules, or transparent spheroids, occasionally escape from this chamber, 
and cii'culate vaguely and iiTcgularly between the periphery of the 
gelatinous body and the shell. Further, the parieties of this 
chamber have a contractile power." The author denied the 
existence of any papillae or proboscides at this part, as well 
as the supposition of Ehrenberg, that these moving molecules con- 
stitute the bases of such papillae. He also denied the statement of 
the same distinguished observer, that if colouring matter was mixed 
with the water in which the Chsterium resides, any motion waa 
communicated to the particles of such colouring matter by the sup- 
posed papillae, or by the active molecules within the terminal cells. 
A circulation of the fluids within the shell was observed, independent 
of the vague movements of the active molecules ; this was regular, 
passing in two opposite currents, one along the side of the shell, and 
the other along the periphery of the gelatinous body. When the 
shell and body of the Chsterium was broken by pressure, the green 
gelatinous matter was forcibly ejected by the contraction of the 
membranous envelope. 

" The action of the iodine upon the specimens was very remarkable : 
1st, it did not, as reported by Meyen, stain the green body violet or 
purple, but orange brown : 2nd, it produced violent contraction of 
the investing membrane of the body, whereby the green matter was 
often forcibly expelled from the shell at the transverse division ; it 
instantly annihilated the motion of the molecules in the terminal 
sacs, and the sacs themselves became so distended with fluid as to 



182 DEscBiPTiox OF [Poli/gastrica. 

hurst, and allow the molecules to escape". — The following arc Mr. 
D.'s reasons for classing the Closterina with animals : — 

" 1st. That while Closterkmi has a circulation of molecules greatly 
resembling that of plants, it has also a definite organ, unknown in 
the vegetable world, in which the active molecules appear to enjoy 
an uadepcndcnt motion, and the parieties of which appear capable of 
contracting upon its contents. 

" 2ndly. That the green gelatinous body is contained in a mem- 
branous envelope, which, while it is elastic, contracts also upon the 
action of certain re-agents, whose effects cannot be considered purely 
chemical. 

" 3rdly. The comparison of the supposed ova with the cytoblasts 
and cells of plants precludes the possibility of our considering them 
as the latter, while the appearance of a vitelline nucleus, transparent 
but molecular fluid, a chorion or shell, deteiTnines them as animal 
ova. It was shown to be impossible that these eggs had been de- 
posited ia the empty shell by other infusoria, or that they were the 
produce of some entozoon. 

"4thly. That while it was impossible to determine whether the 
vague motions of Closterium were voluntarj^ or not, yet the idea the 
author had fonned of a suctorial apparatus forbad his classing them 
with plants. 

" Lastly, in no instance had the action of iodine produced its 
ordinary effects upon starch or vegetable matter, hy coloiu'ing it violet 
or blue, although Meyen asserts it did in his trials." 

The author therefore concluded that Closterium must still be 
retained as an iniusory animal, although it is more than doubtful 
whether it ought to rank with the polygastric families. 



Family.— ASTASIAEA. 

This family is characterized by its members being polygastric, and 
deficient of the true alimentary canal, appendages, and lorica. They 
are furnished with a single aperture, and often with a tail, and have 
the power of changing their form at pleasure. They afford as beau- 
tiful living bjects for the microscope as any that have ever fallen 



Astasiaea.] iNFTTSOEiAt animalcttles. 183 

under my observation. Tlie tail may be coneiflered as an organ of 
locomotion, and the single proboscis of throe of the geneva, and the 
double proboscis of one other genus, have a like otfice. It is pro- 
bable that proboscides exist also in the genus Colaeium, although 
they have not been determined; but in the JDistigma there is hardly 
a doubt of their absence. The vcsicidar cells have been supposed to 
form a portion of the nutritive apparatus, although it is not satis- 
factorily demonsti'ated by the application of colom-ed food. Ehren- 
berg has, nevertheless, noticed some manifestations of an artificial 
action having been produced, as he observed green and red cells in 
the Euglena viridis. Three genera in this family exhibit signs of 
the hermaphrodite condition, whilst the other three. Astasia, Bis- 
tigma, and Colaeium, have only one form of reproductive apparatus, 
namely ova. In the Euglena there may be seen, in addition to the 
green ova and seminal glands, a contractile vesicle of a seminal 
description, and the large red visual points in five of the genera affords 
e\'ident tokens of a system of sensation. What, however, may be 
deemed most worthy of remark in this family is, that in the species, 
Euglena longicauda and amllyophis we have the first indications of 
the presence of nervous matter that is to be found in the polygastric 
Infusoria, in the form of a white glandular knot, situated below 
the eye. 

The following table is descriptive of the genera of this family: — 

Eye wanting Astasia. 

r witli one ( tail wanting Amblyophis. 

C proboscis | 

' With one free ■I { tail present Euglena. 

eye J 

] L with two proboscides Chlorogonium. 

Eyes present < 

L attached by a pedicle Colaeium. 

, With two eyes Distigma. 

The family Euglence {Eugleniens) of Dujardin, in a great measure 
corresponds with that of Astasicea, of Ehrenberg, the first named 
naturalist prefening the term Euglenece, on account of the resem- 
blance of Ehrenberg' s name to that of a family of Crustaceans, 
viz., the Astacice. 

Dujardin looks upon the so called eyes as insufficient to afford 



184 DESCEIPTION OF Poly gastric a."] 

generic characters, -^'hioh he would donve from the nature or appa- 
rent structure of the integumeut, and the number or mode of insertion 
of the filaments. He thus forms a genus Polyselmis, characterized by 
its many filaments ; two genera Zygoselmis and Keteronema, by a pair 
of filaments, in the foraier of equal, in the latter of unequal size. 
The remaining Euglenea have hut a single filament, and can be but 
uncertainly defined ; such are the Eugleneoi mostly coloured, and 
having a red eye speck, and with a tail ; the Astasia without colour 
and tail, but with a filament flexible throughout, and springing 
abruptly from a notch in the anterior estremitj' ; and the Peranema 
differing from the Astasia, only in having a filament rigid at the 
base, and apparently but a continuation of the tapering anterior 
extremity of the animalcule. The two last genera, are, however 
but provisional. 

Dujardin difiers entirely from Ehrenberg, in his interpretation of 
the internal organization of the Astasia or Eiiglenians ; neither 
stomachs, sexual system, ova, or nerve matter are recognized by 
the former. 

The members of this family mostly inhabit stagnant ponds. 
I have always foxind them at the surface. They sometimes tinge 
the water with their own colovir. "When swimming they present an 
elongated form, but when fixed, often appear as round globules. 
They seem capable of progressing, by alternately fixing and ad- 
vancing the head and tail after the manner of a leech; Dujardin 
doubts the oblique fission of Chlorogonium. 

It is with certain members of this family that M. Thuret finds so close 
an afiixity — even an apparent identity, to exist with the reproductive 
spores — Zoospore of the Algae. "This affuiity," he says, is exhibited in 
colour, form, number and character of the ciliaiy filaments, in the 
contents, not excepting the coloured eye-speck, in the mode of self- 
fission, and also in the power of locomotion. "What is still more, 
both Zoospores and Astasicca tend to the light, disengage a gas, most 
probably oxygen, and emit a peculiar spermatic odour. However, 
by continued watchiag the Zoospores are seen to affix themselves 
to some body, surrender theii' seeming animal hfe, and proceed to 
germinate, developing a tissue similar to that of the plant which 
gave them bu'th. On the other hand, the true Astasicea, if they 



Astasiaea.] infusorial animalcules. 185 

attacli themselves, it'is but for a time, and no appearance of germi- 
nation ensues. The closest similarity exists in the case of the 
Chlamidomonas pulnsc/dus, (Bisehm viridis Duj.), and in a less 
degi'ee in the Euglence. (See Part I., page 46.) 

Genus Astasia. — The members of this genus are characterized by 
their being free (not attached by a pedicle), and being furnished 
with a long or short tail, but no eyes. A. pusilla is the only 
species in which digestive cells have been clearly seen. Ova are 
perceptible in A. haematodes, and probably exist in the three other 
species ; a locomotive organ in the form of a thread-Hke proboscis 
exists in A. 2nmlla. 

The immense numbers in wliich these Infusoria are developed in a 
few days, and the blood red-colour they impart, have not unfre- 
quently been the cause of considerable alarm and anxiety to persons 
residing in the vicinity of the waters wherein they are found. 

A. haem(dodi'-s. The llood-lilce Astami. — Body fusiform, or spindle- 
shaped, when extended ; tail \Grj short, body green at first, after- 
wards of a blood-red colour. Group 68 rei)resents one creature 
extended, and another contracted. (Hampstead). Length l-380th. 

A. flavicans. — Body extensible, cone-shaped, approaching cylin- 
drical, and rounded at the foremost extremity. Tail very short and 
blunt ; ovai'ia of a ycUo-svdsh coloui\ Found in yeUow ditch water. 
Length about 1 -430th. 

A. pusilla. — Body extensible, cone-shaped, swelling out, and 
rounded at the fore extremity ; tail very short and pointed, colour- 
less. Group 69 represents two of them magnified. 

Ehi'enberg remarks, they are often so abundant, that thousands, 
perhaps millions, of these creatures are sometimes contained in the 
hollow of a Avatch-glass, and that they rise up and form a stratum 
on the surface of the water. They might be mistaken for the young 
of the A. flavicans , but that the vesicles within them, which appear 
to be digestive cells, are larger than those in that species, which is 
moreover ■ndthout proboscis. As soon as a little colouring matter 
was thrown into the water, an evident current was observed near the 
fore part of the creature; and by this means, in 1833, the thread- 
like proboscis, which is about half the length of the body, was first 
perceived. Sometimes the entii'e creature appeared to glisten. 
Should this species, upon closer inspection, be found to be ciliated, 





186 DEScniPTiON OF XFolygastrica. 

it "woTold be rightly placed in Peridinea. Length l-1440th to 
1 -840th. 

Astasia (?) vwidis. Body extensible, and of an ovate-oblong form, 
distended a little at the middle ; tail very short and pointed ; green. 
Found amongst Conferva. Length l-1200th to l-900th. 

A. nivalis. — Form oval, extremities rounded, rarely pear-shaped, 
colour deep reddish-brown, motion rapid. Found with Protococcus 
nehulostcs in snow (Switzerland). (P. 12, Group 526.) Length 
l-1500th. 

M. Vogt in his account of the Astasia nivalis, describes it as 
invested with a carapace (lorica), open only at the anterior extremity. 
This opening is furnished with numerous small cilia, and here, doubt- 
less, the mouth is situated, the indication of which is given by an 
orange-coloured tint, which is clearer than that of the rest of the 
animal. " The presence of the lorica together with the cilia, are 
characters which do not allow this animalcule to be placed with 
Astasia, as Shuttleworth has done : on the contrary, it ought to be 
placed in the family Peridinia (Ehr.) ; or otherwise be regarded as the 
type of a new genus, distingtiished by the absence of a grove in the 
lorica, and by the stiff hairs of Peridinia being replaced by soft cilia." 
(On the Animalcules of the Red Snow. — Bibliotheque TJnivers de 
Geneve.) 

A. aeus. — Body hyaline, of a long fusiform figure, acute at each 
end, filament the length of the body. Length 1 -650th. Berlin, 

Dujardin's genus Astasia, is defined as colourless, obtuse, or 
rounded posteriorly, whilst those described by Ehrenberg, are mostly 
green or red, and provided with a longer or shorter caudal pro- 
longation. 

The following species are from Dujardiu. 

A. contorta — Body colourless, semi-transparent, containing pale 
yellow granules, cylindroid, enlarged at the middle, obtuse at each 
end, and marked with oblique striae, giving rise to a twisted appear- 
ance. Length 1 -450th. Found in sea water. 

A. injlata. — Body semi-transparent, diaphanous, contractile, ovoid, 
obliquely, but regularly plaited or striated. Length 1 -560th. In 
sea water. 

A. limpida. — ^Body diaphanous, smooth, very variable fusiform, 
more or less obtuse at each end, cleft anteriorly, and often obliquely 



Astasiaea.'] infusorial animalcules. 187 

doubled on itself or twisted. Length l-650th. to l-520th. In 
ditch water. 

Genus Ambltophis. The tail-less eye Asfasiaa. — The charac- 
teristics of this genus are, that it is free, possesses an eye and single 
thi'ead-like proboscis, but is tail-less. The proboscis serves as an 
organ of locomotion, and is situated at the creature's foremost ex- 
tremity, which, says Ehrcnberg, is cleft, so as to represent a two- 
lipped mouth ; the upper lip bearing the proboscis, being very readily 
distinguished. The colour of the animalcule is derived from the 
closely compressed mass of green granules, which nearly fills the 
body, and may be regarded as ova. There may be seen also, near the 
middle of the creature, a large bright globular body, and five wand- 
like bodies, two of which are situated before, and three behind, the 
first mentioned one. The whole of these are supposed to be male 
generative organs. No contractile spennatic vesicle has been ob- 
served. Self-division is imknown in these creatures. The sensitive 
system is more beautifully and clearly developed in this genus than 
in any other of the Polygastric Infusoria. Towards the anterior 
part of the body, and just behind the proboscis, where the mass of 
ova commences, there is a bright red and somewhat lengthened spot 
(resembling, as to situation and colour, the eye of the wheel Ani- 
malcules and Entomasti'aca), beneath which, in the clear space 
below, is a mass of matter of a very peculiar description, of a globular 
fonn, having the appearance of nervous ganglia, and being most 
probably connected with the organ of vision. 

A. viridis. — Body large, elongated, cylindrical, distended or com- 
pressed, and abruptly rounded at the posterior extremity ; green ; 
head colourless ; eye large, bright red. The motion of this creature 
is duU and serpentine, and by its evolutions might easily be mistaken 
for the JEiiglena spirogyra, were that creature, like this, tail-less- 
Group 70 represents three specimens, one full grown, and the others 
young. Found with Euglena, chiefly in the spring. Length l-210th 
to 1-1 40th. 

Genus Euglena. TJie eye Animalcule. — This beautiful genus of 
the family Astasiaea is characterized by its members being furnished 
with an eye, a single thread-like proboscis, and tail, and by their 
being free, that is, not attached by a pedicle. The locomotive pro- 

2 



188 DESCRIPTION OF [Poh/gasfriccf. 

boscis belongs to nine species out of the eleven, and a double appear- 
ance of this organ has been observed in the E. sanguinea, ascribable, 
no doubt, to the preparatoiy condition of the animalcule for self- 
division. 

In Euglena hyalina, E. plcuronedes, and E. longicauda, nutritive 
cells are generally visible, but in the other species they are obscured 
by the masses of green ova, which colour their bodies. Certain in- 
ternal appearances have been recognized, which Ehrenberg supposes 
to be of a male generative nature. Longitudinal self-division has 
been observed in E. acus, and the preparation for it in E. sanguinea, 
as before mentioned. The red visual point indicates the existence of 
the sensitive system in this genus, and a nervous ganglion is visible 
in E. longicauda, as in E. amhlyophis. 

The genus Euglena of Ehrenberg, says Dujardin, contains some 
species of a compressed leaf-like form, and quite deficient of con- 
tractility, and ought to be placed in the genus Phams of the family 
Thecamonadina. 

Respecting the so-called red eye, the French naturalist also remarks 
that it is far fi'om being a tme eye, appearing as it does often like an 
irregular collection of two, thi'ee, or even four granules, sometimes 
with considerable intervals between them, but tliis appearance I have 
observed in several JEntoinostracea when the magnifying power of the 
microscope is not sufficient. 

The Euglena are undoubtedly animals, yet their composition is 
binary, and they evolve oxygen, two characteristics of plants. But 
on the other side, certain mushrooms and other cryplogamous plants, 
are tertiary in composition, having that usual animal element, 
nitrogen ; and they evolve carbonic acid, both characters of animals. 

In the 'Miniature Achromatic Microscope' with a magnifying 
power of 150 diameters, most of the species may be well observed. 

E. sanguinea {Cercaria viridis, M.) Body extensible, of an oblong 
cylindrical or spindle-shaped form, with the head gi'eatly rounded ; 
the tail is short, conical, and somewhat pointed. Proboscis longer 
than the body in its extended condition. "When young, they are 
green, but when full grown, are of a blood red colour. The motion 
of this multifonn animalcule is generally slow, and it sometimes 
revolves upon its longitudinal axis in swimming. Its coloiu' is not 



Astasiaea.] infusorial animalcules. 189 

of a fixed chfiractcT, sometimes beiug green, at others, a mixture of 
red and green. This arises, acicording toElirenberg, from the different 
condition of the ova at different times ; the ova conceal beneath 
them numerous round granular bodies, supposed to be digestive cells. 
The thread-like proboscis, which is a prolongation of the upper lip, 
and rather longer than the body, is so delicate, as to require con- 
siderable care in investigating it, and being retractile, will often 
elude observation. A little coloming matter in the water will 
exhibit this organ in active operation, and it may be distinctly seen 
in a single animalcule, in a di'ied state, upon a plate of clear glass. 
The double appearance of the organ in this species has been before 
noticed. Ehrenberg conjectures that the mii-acle in Egypt, recorded 
by the great lawgiver of the Jews, of turning the water into blood, 
might have been effected by the agency of these creatures, or by the 
Astasia h(ematodes. Figures 71, 72, and 73, represent the creature 
in different states. In the fii'st, it appears elongated, and currents 
in the water are shown near the mouth. In the others, the cilia- 
formed thi'ead-like proboscis is seen. Found in stagnant water, 
often in great abundance, on the surface of ponds. Length 1 -300th 
to 1 -240th. 

i-' EuGLENA hyalina. Body extensible in a spindle-shaped manner, with 
the head attenuated, blunted at the extremity, and two-lipped ; tail 
short, and somewhat pointed ; colour transparent and whitish, rare. 
Length l-280th. 

E. deses (^Enchehjsdeses, M.) Body extensible, cylindrical, abruptly 
rounded at the head, and slightly bi-lipped. Tail very short and 
pointed ; colour green ; motion a winding and sluggish creeping, 
never swimming. Found amongst Lemna. Length 1 -240th to 
1- 760th. 

E. viridis (^Cercaria viridis, M.) Body extensible in a spindle- 
shaped manner, with the head attenuated and sliort. Tail short, and 
cone-shaped, not cleft; colour green, excepting the two extremities, 
which are colourless. The double pointed tail, supposed to have been 
seen by Leeuwenhoek, Ingenhousz Midler, Schrank, and Nitzsch, 
does not exist. The colour of the eye is often pale red, when the 
creature is young, so that it may be easily mistaken for the Astasia 
viridis or Jlouas deses. When diied on glass, the eye seldom retains 



190 DESCEiPTiON OF [^Folygastrica. 

its colour more than a week, but the proboscis may be well examined, 
and preserved in that state. Length 1-240 th. Found on the surface 
of ponds at Hampstead. 

EuGLENA spirogyra. Body extensible and cylinder- shaped, very 
finely striated and granulated. The head is a Httle truncated, and 
the hinder part attenuated into a short pointed tail ; colour a 
brownish-green; motion like E. deses. Found amongst Conferva 
and Bacillaria. Length 1 -240th to 1- 120th. 

E. pyrum. Body obliquely fluted ; when distended oval or pear- 
shaped. The tail generally about the length of the body and 
pointed ; colour green. Group 74 represents two of these creatures 
magnified 400 diameters. Rarely found with any other species. I 
have taken them at Hampstead, but not so frequently as the other 
species. Length 1-1 152nd to l-864th. 

'E. pkuronectes {Cerearia pleuronectes, M.) Body compressed, ovato- 
orbicular, or in the form of an obovate leaf; striated longitudinally; 
colour green ; tail pointed one-third or one-fourth part the length of 
the body, and colourless. Found in stagnant water. Length 1-1 152nd 
to l-480th. 

E. longicauda. Body mostly stiff, compressed, elliptical, and leaf- 
like ; colour green ; tail the length of the body, awl-shaped, sub- 
ulate, and colourless. "Within this creature may often be seen a 
yellowish-green mass of granules or ova. The very delicate vibrating 
thread-like proboscis represented in figs. 75 and 76 has its origin 
from the more projecting side of an indentation on the anterior edge 
of the body, and is about two-thii-ds its length. This creature has 
the power of twisting its body into a spiral form, as seen in fig. 75, 
but not of contracting it. It swims freely, and mostly with a vibra- 
tory motion, occasioned by the action of the proboscis. Found in 
fresh water amongst Conferva and with the Bacillaria. Length 
1 -480th to 1-1 20th. 

E. triquetra. Body leaf-shaped, three-sided, oval keeled; colour 
green; tail shorter than the body, and colourless. See fig. 77. 
Found amongst Lemna. Length 1 -580th. 

E. acui ( Vibrio acus, M.) Body slender, spindle-shaped, and 
straightened in the form of a bodkin ; head attenuated, and a little 
truncated ; taU very pointed , body green in the middle, and colour- 



Astasiaea.] infusoeial animalcules. 191 

less at the extremities. This is one of the most beautiful animalculea 
I have seen under the microscope ; its graceful form when swimming, 
its bright red eye, the curious forms it assumes when stationary, and 
its remai'kable appearance when undergoing self- division, aU com- 
bine to render it worthy of observation. Group 78 shows the normal 
form of this creature ; the figure to the right, the same bent and 
contracted; and the lower, another undergoing longitudinal self- 
division. Found both in fresh and brackish water. Length 1-5 70th 
to l-210th. 

EuGLENA rostrata. Body elongated and conical, vrith the hinder part 
gradually attenuated into the tail, which is very short. Head slightly 
bent, like a beak ; colour green. Found amongst Oscillatoria and 
Bacillaria. Length about 1 -500th. 

E. ovum. — Body ovate green, with a very short hyaline caudal 
prolongation; and a large double circular gland. Size 1 -1560th. 
Found at BerLui. 

E. geniculata. (D.) — Body green elongated, cylindrical, flexible, 
but not very contractile, movement slow, taU tapering, and at an 
angle with the body, hence the name. Length l-208th to 1-I75th. 

This large Exujlena is remarkable by its elongated form, by its 
diameter being nearly equal to its length, without the bulging of E. 
viriclis, and by its articulated tail. 

E. ohscura, (D.) — Body thick, oblong, distended and obtuse poste- 
riorly ; of very variable form, clearer, and of a red tint anteriorly, 
eye-speck reddish black ; filament half as long again as the body. 
Length 1 -870th. 

Genus CHLOEOGOisrnr&r. The Astasia with a double proboscis. — 
This genus comprises those members of the family Astasiaea which 
are provided with an eye, tail, and double thread-like proboscis ; 
thek motion in swimming is free, the creature not being attached by 
means of a pedicle or foot-stalk. The only known species is of a 
very beautiful green colour, and has numerous transparent vesicles 
within it, which are apparently subservient to the purpose of nutri- 
tion, although this fact has not been determined by the imbibition of 
coloured food. A faint, clear, glandular body (the male generative 
system) is perceptible in the centre of the animalcule, the female 
being represented by the mass of green ova, which confers the colour 



192 DESCBIPTION OF {^Polygasfrica. 

on the creature. The double xoroboscis is used as an organ of hico- 
motion, and the bright red eye affords the usual evidence of the 
existence of a system of sensation. Self-division in the transverse 
direction, somewhat modified, has been observed to take place. 

CnxoEOGONiuM euchlorum. — Body spindle-shaped, very pointed at 
both extremities ; tail short; coloiu' sparkling green. The eye of this 
animalcule, although distinctly marked, is, nevertheless, so delicate, 
that it may be easily overlooked ; but when the creature is dried upon 
a plate of very clear glass, both the eye and the double proboscis are 
readily seen, and may be weU preserved as a permanent microscopic 
object. Group 79 represents six creatures in one cluster, each with its 
double proboscis ; above them is one about to divide into tlii'ee ; and 
on the right of this are three young animalcules. Found in water- 
butts, &c. : on ponds it forms the green matter of Priestley. Length 
1-llOth to l-280th, exclusive of the tail. 

It was in this species that M. Weisse thought he had discovered a 
fonn of propagation analagous to that by ova. He observed the 
contained green matter, with its scattered vesicles, contract in some 
measure upon itself, exhibit a constriction, indicating a line of di\'i- 
sion, subsequently followed by the appeai'ance of other constrictions, 
until the entire contents assumed a nodular form, resembling a bimch 
of grapes. This grape-bunch mass possessed a certain degree of 
movement within the enclosing integument, and as the process of 
development further proceeded, its separate particles or granules 
also displayed a movement among themselves, increasing in vigour 
until the outer envelope burst and gave them exit as so many distinct 
independent beings, moving freely about in the surrounding water. 

These young forms so produced, especially in their aggregate state 
before discharge, resemble JJvella Bodo, and M. Weisse thinks Chlo- 
rogonium euchlorum, and Glenornorum tingem, but other stages of their 
development. From the above observation, that naturahst is led to 
the conclusion that Pohjgastrica do reproduce, in some sort, by ova, 
and that some forms described by Ehrenberg as indej^cndent genera, 
are but different phases of development of the same being. 

Genus CoLAcruM. The friends ? of the Water Flea. — This genus is 
characteiizcd by the creatures belonging to it being endowed with a 
BJugU) eye, and attaching themselves to other bodies by means of a 



Asiasiaea.] infusorial animalcules. 193 

pedicle or foot-stalk, which is single, or ramified by the process of 
self-division. The usual locomotive proboscis has not been detected 
in this genus, although, as Ehrcnberg remarks, there can be no 
doubt of its existence, from the currents which are visible in coloured 
water near the forepart of the body. But these being rather feeble, 
render it probable that the organ is a single filiform proboscis. The 
red visual point is indicative of a system of sensation, and the nume- 
rous transparent vesicles within the body denote one of nutrition. 
The creatures are parasitical upon Entomostraca and Rotatoria. 

Chxokogonium (?) vesiculosum. — Body of a spindle-shaped oval form, 
but variable, with the pedicle very short, and seldom ramified ; colour, 
sparkling green, with distinct internal vesicles. Elirenberg says, 
" I have agaia sought in vain for the red eye (May 23, 1835), but 
cannot be satisfied of its non-existence, as it is undoubtedly present 
in the other species, and investigation is sometimes unproductive, on 
account of subordinate circumstances. I have likewise failed in 
seeing very satisfactorily the vibratory organ, notwithstanding its 
action is evident enough." Plate 2. f. 80, represents a portion of the 
back shield of the Cyclops quadricornis (see IIicrosco2)ic Calinet, P. 9), 
with six of these creatiu'es attached to it ; one appears double, longi- 
tudinal self-division having just taken place. Found upon Entomos- 
traceans. Length l-860th. 

C. stentorinum. — Body expansible and vaiiable, somewhat cj'lin- 
drical in form ; its fore part expanded into a cone or funnel-shape 
process ; colour, a beautiful green ; vesicles indistinct, pedicle often 
ramified. Found upon Entomostraceans and Pohjarthra trigla. 
Length 1-11 50th. 

Genus Distigma. The doiible-eyed Astasia. — The characteristics 
of this genus, are, the possession of two eyes, and a fi'eedom of motion. 
Locomotive organs have not been hitherto discovered, and the pre- 
sumption is, that they do not exist, as none of the species either 
swim or produce perceptible currents in coloured water. They have 
a sort of creeping or crawling movement, much like eels, and can 
change their forms, after the manner of the Proteus ; they approxi- 
mate the Amosha in other respects, besides the deficiency of the pro- 
boscis. At the fore part of the body may be seen two very delicate 



194 DESCRIPTION OF Polygastnca.'] 

blackish- coloured spots, analagous to the eyes in the species of other 
tribes. The Distigma are sometimes confounded with Proteus diffluens 
of Miiller. All the species are exquisite objects for a deep powered 
microscope, for instance, one magnifying 460 diameters. 

Distigma tenax {Proteus, M.) — Body larger than in either of the other 
species, proteus-like, at times greatly distended, then as much con- 
stricted : eyes rather indistinct ; colour transparent yellow. Found 
about Lemna. Length 1 -240th. 

D. proteus {Proteus, M.) — Body smaller than the preceding, pro- 
teus-like, sometimes greatly distended, at others constricted, blunted at 
both extremities; eyes distinct. Group 81 represents these crea- 
tures highly magnified. Found amongst conferva. Length 1 -580th. 
to l-400th. 

D. viride. — Body smaller than in either of the other species; 
proteus-like, sometimes greatly distended, at others constricted; 
filled with green granules ; eyes distinct. Length not exceeding 
l-570th. 

D. planaria. — Body small, linear, proteus-like, but less distended 
or constricted than the preceding, pointed at both extremities ; 
colourless ; eyes distract. Found by Ehrenberg amongst Conferva 
in the Nile. Length 1 -240th. 

The following genera and species, are included by Dujardin in 
this family. 

Genus Peranema. — Body of variable form, sometimes almost glo- 
bular, at others distended posteriorly, and drawn out in front, or 
prolonged into a long tapering filament. Movement forwards, slow, 
uniform. 

The Peransma are colourless, but contain in their diaphanous sub- 
stance, granules and vacuolae. The lobes they send out in their 
frequent and remarkable changes of form, are, luilike those of 
the Amceba, covered with an integument. They are found in stag- 
nant marsh water, chiefly on the surface of dead plants. 

I suspect Ehrenberg has described a species fP. protractaj of this 
genus, under the name of Trachelius trichophorus. 

P. protrada. — Body oblong, soft, dilated posteriorly, much ex- 
tended anteriorly. Length l-838th. to l-370th. 



Astasiaea.'] infusorial animalcules. 195 

Peeanema glohulosa. — Body nearly globular, more or less extended 
anteriorly, with oblique plaits on its surface. In the Seine. Length 
l-1625thto l-1300th. (P. 21. f. 13.) 

P. virescens. — The animalcule so named, occurred in the water of 
the Seine, was green, semi-fluid, and changed fonn most rapidly, 
like an Amoeba. Length 1 -860th. to 1-5 20th. Eeqiiires further 
examination. 

Genus Zygoselmis. — Animal of variable form, swimming by 
means of two equal flagelliform filaments, constantly in agitation. 

Zygoselmis is distinguished fi-om Diselmis, by its contractility, 
and its variability of form. 

Z. nehulosa. — Body colourless, sometimes globular, at others, top 
or pear-shaped, with numerous contained granules. Length 1-1 300th, 
with two filaments of equal size and length. (P. 21. f. 12. a. b.) 

Genus Heteeonema. — Body of variable form, oblong, irregularly 
dilated posteriorly, having a fine flagelliform filament, and a second 
thicker trailing one, acting as a retractor. 

This genus, by possessing the two filaments, of different characters 
and office, approaches the Ueteromita (137) and Amsonema (150) ; 
from which, however, it is distinguished by its contractile, obliquely 
striated integument. 

H. marina. — Body oblong, irregularly dilated behind, narrower in 
front, obliquely and closely striated. Length 1 -434th. Foimd in 
sea water. (P. 21. f. 11.) 

Genus Polxselmis. — Animal oblong, of variable form, swimming 
by means of several flagellifonn filaments, arising fi-om its anterior 
extremity. 

The single Infusorium (says Dujardin) bearing these characters, 
resembled an oblong Euglena, rounded at each end with an anterior 
longer moveable iilament, suiTounded by three or four very fine 
shorter ones. 

P. viridis. — Body elongated, rounded at each end, more or less 
dilated, and folded at the middle ; green, with a red eye-speck. 
Length 1 -650th. Found in a glass of marsh water, containing 
Lemna, and which had been kept several months. (P. 21. f. 7.) 



196 DE8CBIPTI0N OF \_PoJy(jastrica. 



Fajiily.— DINOBRYINA. 

The animalcules of this family are distinctly, or to all appearances, 
polygastric, and furnished with only one aperture to the body; 
hence, like polypes, they can have no true alimentary canal. They 
are possessed of a lorica or shell, and have the power at will, of 
changing their form, but are \Wthout appendages. In one species of 
the genus Dinohryon a simple filiform proboscis is present ; and in 
the same genus, a delicate red sjjot, at the anterior portion of the 
body, indicates the organ of vision. The nutritive apparatus is 
obscure and undefined. The lorica is of the form of a Kttle pitcher 
(urceolus), at the bottom of which the very contractile Euglena-Hke 
creature is attached. Two genera only are known. 

Genus Epiptxis. The Pedestal Animalcule. — The characteristics 
of this genus are mostly of the negative kind ; it wants the eye and 
is attached. The most evident animal character possessed by the 
species is the funnel-shaped orifice at its foremost extremity. The 
soft or pulpy body is lodged within a delicate membranous (not 
siliceous) lorica, wliich is usually afiixed by a pedicle, or foot, to a 
piece of Conferva. 

E. utricidus. — Body of a conical pitcher-like form, small, and 
filled with yellowish granides ; attached by a pedicle. Group 82 
represents several of these creatures attached to a portion of conferva. 
Length 1 -640th. 

Genus Dinobeyon. — This genus is distinguished from the pre- 
ceding one by possessing an eye, and cnjoj-ing a freedom of motion. 
The lorica also is more free from the body of the creature than in 
Epipyxis. Eeproduction takes place by gemma or buds, which do not 
separate from the parent ; hence a shrubby, forked, and Monad-like 
cluster is produced. 

D. sertularia. Body large, invested with a lorica, slightly excised, 
and dilated at the mouth, but constricted near the base. Developing 
in the form of a shrub. (See group 83 and tig. 84.) This animalcule 



AmoBbaea.] infusortai- antmat,cui,f,s. 107 

is not readily soon, hj reason of its crystalline lorica, and colourless 
body : by a patient investigation, however, the little shrubby 
colony may be perceived rolling along, and advancing in the field 
of view. Within each lorica a pale yellow animalcule may be 
noticed, in form somewhat resembling the young of the CJdorogonium 
or Etiglena riridis. This creature has the power of stretching itself 
out in a spindle-shaped manner, so as not to protude, however, 
beyond the mouth of the lorica, and also of contracting itself into a 
globular form. The red point is observable at the anterior part of 
the body, and a single thread-like proboscis is thrust forth from out 
of the shell. Cluster 83 represents a shrubby cluster, containing 
eight animalcules, and the shells of three which have died. The 
vibrating proboscides act like so many paddles in the water, and 
propel the moving mass. Found in bog-water. Length of single 
animalcule l-570th; ditto of cluster 1-1 20th. 

DiNOBRYON (?) sociale. — Body small, enveloped in a shell of a simple 
conical shape, truncated at the mouth. Developed in the form of a 
shrub. Found in fresh water. Length 1 -860th; ditto of cluster 
l-280th. 

D. gracile. — Less branching ffruticosej, lorica slightly constricted 
at the middle, apertiure truncated. Size of single animalcule 
1 -2080th, 



Family— AMOEBAEA. 

The animalcules of this family are polygastric, with one aperture 
only to the body, and no alimentary canal or lorica. No other 
organs of motion are observable than certain appendages or ramifica- 
tions, consisting of variable pediform processes, which they have the 
power of putting forth from every part of their gelatinous and contrac- 
tile bodies, and by which they move from place to place. The organs 
of nuti-ition are composed of numerous digestive cells, which are visible 
in all the species, either in their natural state, or by the introduction of 
coloured substances into them. Self-di\dsion has been seen in Amcela 
diffluens. No indications of a sensitive system are discoverable in 
any species. As only one genus is known, its characteristics are 
represented by those of the family. 



198 DESCRIPTION OF [Polj/cfastrica. 

This family, along with the ArcelUna, form a very natural group 
of Infusorial beings, especially, characterized by their pulpy con- 
sistence, and variable expansions, serving the purposes of locomotion, 
and probably of prehension. This group has pretty generally re- 
ceived the appellation of Rhizopodes ; a term derived from their root- 
like processes or feet. The extent of signification however, of the 
name, has, unfortunately, not hitherto been sufiiciently determined 
ujion : thus, Siebold (Lehrbuch der Vergleichenden, Anatomic, der 
"Wii-bellosen, Thiere. Von. c. Th. N. Siebold. Berlin, 1848. p. 11.) 
uses it for aU the beings in the families, Amwboea and Arcellma ; 
whilst Dujardin restricts its use to the genera, included in the family 
ArcelUna, (Ehr.) with some others, but excludes the Amoeha. 

The term Rhizopoda is useful to define the entire group, which 
may indeed be called a class. (See Page 58.) 

Speaking of these pecuKar animalcules, Siebold observes, that 
little is known of their internal structure, but they appear allied to 
the Infusoria. Their bodies may be compared to a simple cell, 
containing in their Parenchyma, a firm nucleous body, analagous to 
that of the Infusoria, no special organs can be distinguished unlike 
the true Infusoria. The Rhizopoda have no fixed form, no ciliated 
surfaces, but are moved slowly onwards by ramifying processes, 
protruded at various parts of the body, and continuous in substance 
with it. 

Some of the Rhizopoda of Dujardin, are considered by Ehrenberg, 
to belong, not to the Infusoria, but rather to another order of beings, 
called by him Polythalamia, and by M. A. D'Orbigny, Foraminifera. 
The main difference, separating the Rhizopoda from the Polythalamia, 
is, according to Ehrenberg, the calcareous composition of the shells 
of the latter, and the siliceous constitution of the Foraminifera. 
Another general distinction between the two classes is, that whereas 
in Polythalamia the variable and gelatinous processes protrude through 
numerous regularly disposed holes, (foramina) in the shell, those of 
the Rhizopoda, on the contrary, escape from a single opening of 
greater dimensions. 

The following account of the habits and appearance of the Amoiba, 
given by Dujardin, convey a clear notion of those animalcules. 

We may, in the first instance, perceive, on the glass slide, (under 



Amoebaea'] infusorial ANiMALCutEs. 199 

the microscope) small rounded masses, semi-transparent or nebular, 
and motionless, but presently an expansion or rounded lobe, quite 
transparent, may be seen to proceed fi'om the circiimferencc of one or 
other of these masses ; this expansion insensibly glides along the 
surface of the glass slide like a drop of oil, and then fixing itself at 
some point, slowly draws onward the remaining bulk. 

In this mode the vitaHtj^ of the Amceha is manifested, the expan- 
sions constantly varying in form, arrangement, and number, even in 
the self-same being. Some constancy in the foi-m and proportionate 
size of the processes is however, met with in the diflerent Amosbee, 
and is employed in the discrimination of species. 

Young Amcelce are perfectly transparent, but in proportion as they 
increase in size, they lose their transparency by the accretion or 
imbibition of numerous corpuscles or granules, which have been 
looked upon as ova or the materials of nutrition. Amongst such 
particles, various matters, derived from without, are found thus 
imbibed or swallowed, such as starch granules, Naviculae, vegetable 
debris, &c. Their mode of introduction is accounted for by the way 
in which the Amcehce move along, their bodies being closely adherent 
to the surface to which they are afiixed, and also so pressed as to 
take up any particles in contact, which by successive expansions 
and contractions become at length imbedded. Before admitting this 
interpretation of the phenomenon, Dujardin's assumption of the 
absence of an integument must be admitted. 

But, further, the gelatine-form bodies of the Amcelxs are capable of 
having vacuolae spontaneously formed, either at, or near the surface, 
which may ultimately collapse and disappear. By such means, 
foreign bodies may likewise become introduced within the organism. 
" It is, however, difficult of belief, that these included particles, 
by reason of the consistence and imalterability of many of them, 
can serve to nouiish the Amceha;, but still, whilst admitting that the 
AmoehiB are noui'ished by absorption, I do not deny that they may 
find means of still more readily absorbing elements of nutrition, by 
swallowing various foreign bodies, and of thus increasing their ab- 
sorbent surface. If it must in aU cases be supposed that these 
foreign particles enter by a mouth, and are lodged in stomachs. It 
must also be allowed, that this mouth is produced at any spot, and 



200 DESCEiPTioN OF [PoJi/ffash'Ica. 

at the pleasure of the Arnceha ; to be presently re-closed, and to dis- 
appear, whilst that the stomachs themselves, devoid of any proper 
membrane, are hollowed out indifferently here and there, according 
to the requirements of the animal, to disappear after the same 
fashion ; in this case only the words employed would differ, the 
explanation of the phenomena would remain as I have given it." 

" Of other corpuscles or granules contained in the substance of 
the Amoebm, some, of extreme tenuity, and irregular, appear to differ 
from the general gelatinous substance only in density, and I am in- 
duced to consider them a product of secretion rather than ova. They 
move about and appear to flow along with the glutinous mass in the 
expansions pushed out by the animalcule ; they, in this way, aid 
the observer in detecting the very slow movements of the Amoehce. 
The remaining sort of granules which, on account of their unifoiTQity, 
ought, with better reason, to be looked upon as ova, are chiefly 
observed in the large Amosbm, in which they are seen to move hither 
and thither, according to the position of the expansions thrust out, 
into which, indeed, they advance to a greater or less extent. But 
these ovoid bodies appear to me too consistent and too homogenous to 
be ova, they refract light, indeed, as strongly as starch granules." In 
fine — " I am disposed to regard most of the internal granid.es of 
Amcehcc as foreign to theii' organization." 

"The Amccha, once developed, may doubtless multiply by spon- 
taneous fission, or by the tlirowing off of a lobe which immediately 
commences an independent existence. The only experiment I have 
tried on this point in a large Amoeba, has convinced me that, by the 
tearing or section of the mass, no escape of the internal glutinous matter, 
or of the contained granides occurs, but that each segment contracts on 
itself, and continues to live. In this may be found evidence of the 
non-existence of an integument." 

" Ehrenb erg attributes to the Amcehce a resistant, contractile, and 
very clastic integument, and he explains the production of the 
variable expansions on the supposition that the integument becoming 
relaxed at some one part of its surface, at the will of the animal, 
there results therefrom at such spot, a sort of hernia, all the rest of 
the integument, by virtue of its contractility, compressing the viscera 
and internal organs into the dilated portion of the integument." 



AvtmhaPcU^ tNFrSORTAL ANTMALCULESi ^*- 

The oxtenial affinity of the Amoeha with sponges is very close ; 
they may indeed be called microscopic sponges. The resemblances 
are well conveyed by Mr. Carter, in the following interesting descrip- 
tion of a fresh water sponge. " A ragged portion torn ofi" with a 
needle, will be seen gradually to assume a spheroidal form ; and if 
there be a spiculum, it will embrace it within its substance, it may 
even be seen to approach it, and it may bear away the spiciaunl> 
having, as it were, spit itself upon it. On its circumference, will be 
observed little papillae, which gradually vary their form, extending 
and retracting themselves, until one of them may be seen to detach 
itself from the parent-mass and go off to another object. This 
little animal, one of the group which it has left, may remain 
stationary on the second object, or descend to the watch-glass, 
assuming in its progress all forms that can be imagined, spheroidal 
or polygonal ; whilst every point of its body appears capable of ex- 
tending itself into a tubular attenuated prolongation .... These 
transparent little sacs (the gemmules of Grant and Hogg) are some- 
times flUed with green matter. They appear to be able to adapt 
themselves to any form that may be convenient for them to assume, 
and when forcibly separated from each other (by tearing to pieces a 
minute portion of the sponge under water in a watch-glass), the 
isolated individuals may be seen to approach each other, and to apply 
themselves together in twos and thi'ees, &c., and so on, imtil, from a 
particle, only discernible by the microscope, they assume the form of 
an aggregate mass, visible to the naked eye, and such a portion, 
growing and multipljnng, might ultimately reach the size of the 
largest masses adhering to the sides of the tanks at Bombay. They 
appear to belong to the genus Amoeba of Ehrenberg." 

These changeable globules, Mr. Carter, in the subsequent part of 
his paper, designates Proteans ; and states that they commonly 
resemble the Proteus dijjiuens, Mliller. (Notes of the species, &c., of 
the Freshwater Sponges of Bombay. " Trans. Med. andPhys. Society, 
Bombay, 1847. Appendix.) 

Genus Amceba. 

A. princeps {Proteus diff. M.) — Body of a pale yellow colour, 
furnished with numerous variable processes, somewhat cylindrical in 

p 



202 DEscEiPTioN OF \^Pohirjastrica. 

form, with the tenninations thick and rounded. This curious crea- 
ture, from its slow motion and yellowish colour, is a desirable object 
for the microscope ; its singular changes of form, and its internal 
organization, may be viewed with considerable pleasure, under very 
high magnifying powers. Its normal shape, if such it can be said 
to possess, is globular, but it can relax any portion of its body, and 
contract the rest, so as to force the internal part down into this 
relaxed portion, which thus becomes so to speak, a hernial tumour ; 
ten or twelve processes may sometimes be seen extended at one time. 
Figures 85, 86, and 87, represent three animalcules highly magnified ; 
the first has only two processes extended; in the last there are 
several. Foimd amongst Naviculco. Size 1- 140th to 1 -70th. 

Amceba verrucosa. — Body less than that of the last species, and 
coloTirless ; globular or ovoid processes, very short and blunted, re- 
sembling warts; motion sluggish. Size never exceeding 1 -240th. 

A. diffiuens ( Vohox sphoerula, M.) Body expansible and colourless; 
processes longer than the last, strong and more pointed. This species 
is a very interesting object for the microscopic observer ; its body 
resembles sometimes a transparent, at others a turbid lump of 
jelly, slowly expanding and stretching itself out, and here and there 
exhibiting its pointed processes, which again disappear as it advances. 
Its motions may be compared to those of a many-footed animal tied 
up in a sack. Found in Hackney Marsh, amongst Lemna. Usual 
size about 1 -300th. 

A. radiosa. — Body colourless, and less than that of the preceding 
species ; its processes, which are numerous, are long and slender, 
pointed at the ends, and apparently radiating. This animalcule, 
when in a contracted state, is not distinguishable from the A. diffluens, 
but when fully expanded may be likened to a porcupine. It 
readily imbibes colouring matter. Fig. 88 resembles one of these 
creatures in a contracted state, and 88* the same with the processes 
thrust forth. Found in bog- water. Size 1 -240th. 

A. longipes. — Very small ; processes very long ; a single one, often 
four times longer than the body, acute, hyaline. Body 1 -2500th. 
In North Sea, at Cuxhaven. 

A. Roeselii (Duj.) — Diaphanous, expansions numeroiis, some very 



Amnphnetl.] INFrSORTAL ANIMALCUmS. 203 

obtuse, others digitate, and others also pointed or jagged. Size 
1- 130th. Large vacuolte were noticed about the middle of the body 
looking like large globules. 

Amcebjl marina, (D.) Ameeba, filled with granules at the centre, 
and differing from the A. dtffiuens only in its dimensions and habit, 
i. e., the sea. Length 1 -260th. 

A. Gleichenii, (D.) — Changing from a round globular to a very 
long oval figure, and dividing into two or three lobes at one ex- 
tremity ; it often exhibits vacuolse, and nearly opaque nebular bodies 
at the centre Length 3-2600th to 7-2600th. 

A. muUiloha, (D.) — This may be but a variation of A. Gleichenii, 
but deserves pointing out as much from the circumstances of its 
appearance as from its form. Length 1-1 300th. It seems softer 
than other species, and moves actively, emitting from its border in 
various directions ten or twelve rounded lobes, assuming thus a most 
irregular figure. It was found in an infusion of meal which had 
been kept nearly two months. 

A. Umax, (D.) — Body diaphanous, rounded at each end but slightly 
lobed, gliding along in a nearly straight line, containing very distinct 
granules, and a very clearly marked vacuola. Was found in the 
water of the Seine, kept for eight months. It may be but a more 
advanced degree of development of the preceding, or of the follow- 
ing species, its greater transparency, however, and its semi-fluid 
consistence, seem sufficiently distinctive. Length 1 -260th to 1 -800th. 

A. guttula. (D.) — Diaphanous, orbicular or oval, gliding in a 
straight course, and containing very distinct granules. This is one 
of the most common species, but may easily escape notice on account 
of its great transparency, the simplicity of its form, and the slow- 
ness of its movements. Found in river or marsh water, kept for some 
time, and containing plants. Length 1 -520th to 1 -890th. 

A. lacerata, (D.) — Body symmetrical, rugose, plaited, and granular, 
rather diaphanous, with broad expansions, as though membranous at 
the base, and terminated by several tapering torn points ; one or 
more evident vacuolte. Length l-2800th to l-890th. In pond 
water. 

A. hrachiata, (D.) — Body globular; semi-transparent, porous and 
tubercular, with four to six very thin, long, and cylindrical expan- 

p 2 



204 DESCHiPTiON OF \^Pol ijfjcuirica. 

sions, straight or flexiiose, sometimes bifid or branching. In animal 
infusions. Length 1- 190th. 

Amceba crassa, (D.) — More or less rounded, thick, containing nu- 
merous granules, expansions circular, numerous, not very prominent, 
Length 1 -880th to 1 -520th. In the water of the MediteiTanean. 

A. ramosa, (D.) — Body globular or ovoid, containing a great 
quantity of granules, and emitting numerous expansions of nearly 
equal size, rounded at their extremities, and of the same length as 
the body, and mostly branched. 

Other varieties of these peculiar beings are refen-ed to, but not 
specially described by Dujardin, to one, however, he proposes the 
name of Amoeba injiata. 

Dujardin appends the following obscrv^ations : — 

"It is impossible to establish Zoological species in the case of 
animalcules, having no determined form, without appreciable organi- 
zation ; the mode of origin and of reproduction of which, are alike 
imknown, and upon which we may suppose the nature of the liquid 
produces very great changes. For, from what precedes we may con- 
clude, that most of the Aniceha described, are developed in saline 
solutions, more or less saturated, and often also in liquids, having 
their fluidity diminished by organic matter held in solution." 



Famixy.— AECELLINA. 

This family contains polygastxic animalcules, which possess an 
alimentary canal, a single opening of the body, are provided with a 
loriea, and can change their figure by means of variable pediform 
processes. The loriea, which is univalved, is pitcher or dish-shaped, 
and the possession of it is the chief feature, distinguishing this 
family from the Amcehaea. The body is soft and gelatinous, and in 
some cases appears to flow, as it were, from the opening of the loriea. 
The organs of locomotion are soft variable processes, situated at the 
anterior part of the body ; they are sometimes withdrawn, at others 
protruded ; sometimes they appear simple, at other times branched. 
In five species, numerous digestive vesicles are seen. No traces of 
a sensitive system have been discovered. The reproductive system 



Arcelliiia.] infusorial animalcules. 205 

is imknoAyn, neither has increase by self- division, by the formation 
of gemmae, or otherwise, been recognized. 

The shell or loriea of the Arcellina or Rhhopodes, varies much in 
figure, and especially in the condition of its siu'face, which may be 
smooth, or variously, and oftentimes beautifully sculptured, or beset 
with spires or other prominences. The Rhizopoda have a close 
affinity to the Pohjthahmia or Foraminifera ; indeed, some authors, 
as Dujardin and Schlumberger, describe as ^Azko/?oic;s, several genera 
placed by others — Ehrenbcrg, D'Orbigny, &c., among the Pohj- 
thalamia. These doubtful genera include beings with more complex 
loricse, than those strictly of an Infusorial character. 

In determining the various species of Arcellina, the dimensions, 
figiu-e, and other circumstances pertaining to the opening (mouth) 
of the loriea, are of gi'eat importance. The loricae may often be 
foimd empty, they may be frequently seen tinted orange-yellow, or 
brown ; theu- consistence also varies, fi'om a flexible parchment-like 
material, to a brittle siliceous (calcareous) substance. Some of 
the Rhizopoda attain such dimensions, as to nearly fall within the 
compass of unaided vision. 

Some are marine ; others as the Bifflugia, live in fresh water. 
Concerning their habit, we may quote Dujardin's account, who 
says ; " The Rhizopodes being deprived of the power of swimming, 
and compelled to merely crawd (glide), when not fixed to the surface 
of bodies, are consequeutly to be met with only upon aquatic 
plants, between the leaves, which afford them shelter, or in the 
stratum of debris, about the base of such plants, or between the 
asperities of the shells of marine mollusks. They are not met 
with in infusions, although they Avill live a long time in bottles con- 
taining any plants, which may serve them for an abode, and in such 
cases they will very soon be found crawling on the surface of the 
glass, and be easily observed." 

Speaking of the afiinities of the Foraminifera, D'Orbigny remarks, 
" From what precedes concerning the characters of the Foraminifera, 
it is. evident they cannot be arranged under any known class of 

animals Their place in the animal kingdom is, as au 

altogether independent class between the Echinodermata and Polypes ;^^ 
(Foramiuiferes fossiles du Bassin, Tertiare de Vienne, p. 17, 1846.) 



206 DESCRIPTION OF {JPolyfjastrica. 

M. Agassiz, on the contrary, would elevate them among the Gm- 
teropoda. (Annal Nat. Hist., 1850, p. 156.) 

The genera are related to each other as follows : — 



Changeable processes / Lorica spherical or tun-like Difflxipia. 

radiant, < Lorica a flat spiral Spiriilina. 



! 



generally numerous ( Dish or shield-shaped Arcella. 

Changeable processes broad and undivided Cyphidium. 

Dujardin divides the Rhizopodes into two sections, According to 
the form of the variable expansions, " The first section corresponds 
to the family Arcellina of Ehrenberg, and comprehends those species 
provided with short thick expansions, rounded at the extremity. 
Such are the Bifflugice, possessing a flexible membi-anous lorica, 
without visible texture, mostly of globular form, whence radiate 
the expansions : such too, are the Arcellce, having a discoid lorica, 
flattened on the side, along which it moves (the plane of reptation), 
where is a central round opening, from which the expansions proceed, 
the latter lying thus between the shell and the surface, along which 
it glides. The lorica is, moreover, brittle, often reticulated, or 
areolated, and indications of a spiral ; not a symmetrical arrange- 
ment present. The second section much larger, comprises all th 
varieties of form, presented by filiform expansions, very fine at the 
extremity. Of these varieties I make three tribes ; the first dis- 
tinguished from the Difflugim only by the slender character of the 
expansions ; however, in one genus of this tribe Trinema, the opening 
is lateral ; and certain species, forming the genus Euglypha, have a 
lorica beset with tubercles, or areolae, disposed spirally ; whilst the 
third genus Gromia, has a spherical membranous shell, and very long 
and branching expansions." 

The remainder of the Rhhopodes, as described by Dujardin, are 
located by other authors with the Polythalamia, they are marine 
animals, having a calcareous shell, mostly very delicate and elegant, 
and presenting a miniature, as it were, of the Nmitili and Ammonites, 
but always divided into many cells (chambers.) Out of these 
beings, Dujardin constitutes two other tiibes of his so-called Shi%o- 
podes : one represented by the single genus Miliola, which, like 
Gromia, and the other examples of the first tribe, has but a single 



Arcellina.j infusorial animalcules. 207 

large opening in its lorica for the escape of the expansions ; the other, 
by numerous genera, in all which numerous filiform expansions 
emerge fi-om many distinct pores (foramina) ; hence the name 
applied to them by D'Orbiguy, of Foraminifera, and by Ehrenberg, 
of the Greek equivalent, Folythalamia. 

Of these porous animalcules, Dujardin cites but the subse- 
quently named genera, viz , Vorticialis, Cristelh/ria, Rosalina, and 
Planorbulina. 

Kcfcrcnce to the system advanced by Siebold, page 62 will show 
that this naturalist in forming his class Rhizopoda, has included in his 
family ArcelUna, the genera constituting the first and second tribes 
of Dujardin, and has created an order, Polysomatia, for the undoubted 
Polythalamial genera, Vorticialis, Geoponus and Nonionina. 

In the ensuing descriptions of the species Arcellina, we shall 
confine ourselves to the beings embraced in the Arcellina of Ehren- 
berg, and in the two fii-st tribes of the second section of the plan of 
M. Dujardin. For an account of the Palythalamia or Foraminifera, 
we may refer to the splendid work of D'Orbiguy, before named, and 
to the various papers of that author, and of Professor Ehrenberg. 

Genus Ditflugia. The diffluent Animalcules. — This genus is cha- 
racteiized by the creatures having the variable processes, -which issue 
only from the fore part of the body, numerous, or each one cleft 
into several parts, so as to give it the appearance of being many. 
The body is enveloped in a horny pitcher-like lorica, sometimes glo- 
bular, at other times oblong or spiral in form, and either smooth or 
sculptured. The lorica of this genus being opaque, except in 
D. enchelys, little of the internal organization of these creatures is 
known ; in B. enchelys, numerous digestive cells have been seen. In 
D. proteiformis and B. acuminata, the lorica is covered with grains 
of sand, similar to that of the caddis- worm. In D. oUonga and 
D. enchelys, the shell is smooth. 

D. proteiformis. — Lorica ovate and subglobose, as represented in 
figs. 89, 90, and 91 : it is roughly coated with minute grains of 
sand, and is either of a blackish or greenish colour. The transparent 
processes vary in number from one to ten. In fig. 89, six are pro- 
truded. M. Lc Clerc describes this species as having spu'al coixu- 



208 DESCRIPTION OF {^Polygastrica. 

gatious on the lorica, which Ehrenberg does not appear to have 
seen. Found among Oscillatoria, &c. Size 1 -240th. 

DrFFLUGiA oblonga. — Shell oblong, rounded, smooth, and of a 
bro-v\Tiish colour. The transparent processes fewer and stouter than 
those of the preceding species. Found among Oscillatoria, &c. 
Length 1 -200th. 

D. actmiinata. — Shell oblong and rough, being covered with mi- 
nute grains of sand ; posteriorly pointed ; processes transparent. 
Length l-70th. 

D. enchelys. — Shell oval ; coloiu'less ; transparent and smooth, 
rounded on the back ; processes transparent, slender and small ; 
aperture lateral. This is the smallest species of the genus. Size 
l-550th. Foxind in stagnant water. 

D. ampulla. — Lorica oblong, club-shaped, elegantly marked by an 
oblique series of dots fpunctaj : hyaline, with an ovate opening. 
Size 1 -680th. Foimd by Dr. Werneck at Salzburg. 

D. spiralis, (Bailey). — Lorica sub-globose, minutely granulated : 
upper surface unequal, with a spiral suture of two or three turns. 
Pseudopodia, (variable processes) long, numerous, constantly changing 
positions, hyaline. Size 1-6 80th. Found at Berlin, and common in 
the United States. 

D. acanthophora. — Lorica ovate, oblong, areolated, loosely foramen 
dentated, armed posteriorly with three or four spines (^aculeij. 

D. a/reolata. — Lorica and foi'amen, as in the preceding, but the 
spines deficient. 

D. denticulata. — Lorica ovate, oblong, smooth, foramen (mouth or 
ostiola) with twelve dentations, 

D. lacjcna. — Lorica clavate, of the form of a bottle, smooth, with- 
out reticulations, margin of opening entire. 

p. laevigata. — Lorica ovate, oblong, smooth, foramen with eight 
dentations, approaches D. denticulata. 

1). striolata. — Lorica ovate, oblong, dehcately striated longitudi- 
nally ; foramen with a dentated border. 

D. hruderi. — Lorica ovate, surface rugose, the end presenting the 
aperture rather attenuate but truncate ; margin of apertirre entii'e. 
Length I'iO^Oth. Found on moss. 

1), c'«/<a'?7(?^«.— -Lorica oblong, obtuse ; siuiacc beset with imper- 



Arccllina.] iNFUSoiiiAL animalcules. 209 

fectly roimdcd cells, 5 — 6 iu l-2500tli; upcrtiu'e narrow, entire. 
Length l-lOiOth. Found on moss. 

DiFFLUGiA ciliatu. — Lorica ovate, surface areolar ; each posterior 
areola fiu-nislied with a eilium or cirrhus; constricted towards the fora- 
meu which has 10 to 16 dcnticulations. Length 1 -936th. Common in 
Hcrcynia. 

D. seminulum. — Lorica shorter, ovate, brown, surface mth narrow 
and small ai'eolse, aperture wide, very finely denticulated or entii'e. 
Length l-2500th to l-1250th. On moss and stones. 

D. colJaris. — Lorica formed like a neck behind the aperture ; 
straight, attenuate, pyriform or sub-clavate ; smlace irregularly 
cellular, the cells small, but of equal size, except about the neck, 
where they are smaller; aperture entire. Length 1 -840th. About 
roots of trees. 

D. dryas. — Lorica ovate, with longitudinal linear rows of ovate 
cells ; apertui-e entii-e, truncate. The size of cells decreases poste- 
riorly. Length 1-11 70th. On roots of trees. 

D. oligodon. — Smooth, oblong, sub-cylindrical, apertiu-e with eight 
strong dcnticulations. Length 1-lOOOth. This species and the two 
following found in Kurdistan. 

D. reticulata. — Lorica ovate, surface broader, marked by a net- 
work of minute cells ; apertiu-e simple, large. In its interior are 
nvmierous particles like aggregated buds ; or the margin of the fora- 
men may be furnished with dentations. Length 1 -880th. 

D. squamata. — Lorica ovate, Avith large loose areolae looking like 
scales (squama) ; aperture with dcnticulations, truncate contracted. 
Length 1- 1450th. 

The next species, is from Dujardin, those following from Sclum- 
berger. [Annales des Sciences Nat. 2,mo. Series, vol- iii. 1845, 
p. 254.) 

D. glohulosa. — Lorica brown, globular, or ovoid, smooth. Length 
l-260th to l-105th. Found netir Paris. 

D. d&pressa.—LoviQ.ai diaphanous, ovoid, depressed, resistant; its 
surface divided by slight fissures (lines) into numerous small and 
irregular polygonal sections. Length 1 -220th. Apertui'c with au 
uneven margin. Found in springs, Vosges. 

D. (jigaatm. — Lorica, greyish, brown, rough as if screwed with 



210 DESCBIPTION OF \_Polji/gastric(u, 

particles of sand, ovoid, elongated, and contracted anteriorly. Length 
1 -325th to 3-325th. It approaches D. proteiformis, but differs in 
its more elongated form, in being contracted anteriorly and almost 
pyi'iform, in being sometimes depressed, and lastly in its greater 
size : margin of aperture uneven. 

Genus SpiEiLLnsrA. — Lorica tubular, siliceous, rolled in a spiral 
manner, resembling the shell of a Planorhis. It is allied to Dijfluyia, 
Avith a siliceous lorica — acids exert no action on the shell. This genus 
probably agrees with the SpiruUna of Bory St. Vincent, but the 
latter name has been otherwise used by Ehrenberg to designate a 
genus of Polythalamia. 

S. vivipara. — Shell porous, convoluted as a circular, spiral, hori- 
zontal tube, hyaline and smooth. Young lorica3 may often be foimd 
connected with it. (P. 14. f. 37.) Found living in the sea — Vera 
Cruz, Mexico. 

The form of this species recalls that of many undoubted Polytha- 
lamia, whilst it has no fellow among the Infusoria. Ehrenberg has 
lilfewise represented apparent dots or pores on its surface, like those 
tlu'ough which the filiform processes of Polythalamia are proti'uded ; 
and the only reason implied in Ehi'enberg's account of this organism, to 
reckon it among the Pohjgastrica, is, its siliceous shell. It will be 
noted that Elirenberg is inclined to believe it viviparous. 

Genus Aucella. — The capmle Animalcules possess numerous 
variable processes, or single processes, cleft into many, and spread 
abroad, and is furnished with a flattened shield-hke lorica. The 
structure of the lorica, as to details, is very different in the various 
species. For instance, in A. vulgaris it exhibits regular and delicate 
facets; in A. dentata, the facets are large and crystaUine; in A. 
aculeata, it is beset with spicula , and in A. hyalina, it is homo- 
geneous and clear. The organs of locomotion are extensile and 
retractile processes, radiant and variable. The digestive cells are 
readily filled with colom-ed vegetable substances. In A. vulgaris, 
a contractile vesicle has been perceived. 

"The Arcellce (says Dujardin,) seem to differ among themselves 
by the intimate structure of their lorica, which sometimes appear 
membranous, at others finely striated, reticular, or with granules dis- 
posed in spiral lines. Some Arcellce have also spinous prolongations 



Arcellina.'] infusoeial ANTMALcrLES. 211 

from the border of their h^rica. Pressure fractures their lorica like a 
brittle substance. By the cracks so formed, the contained substance 
escapes, extending iu the form of contractile expansions, as in the 
Amoeba. I have seen one larger lobe almost separated, as if about 
to become an independent being. M. Peltier has observed contact 
to take place between the expansions of neighbonring Arcella without 
any imion being effected, while the processes of the same Arcella 
will unite and become blended together. 

The lorica in young Arcella is extremely diaphanous, and gra- 
nulations or striae are to be seen only in those of lai-ger size, hence it 
may happen with respect to some species that they represent but dif- 
ferent stages of existence of the same animal." 

A. vulgaris. — Lorica, round and bell-shaped, with a hemispherical 
or turgid back ; smooth, and composed of rows of minute granules ; 
colour yellow or reddish brown. Found abundantly amongst lemna 
and aquatic plants. Size 1-5 70th to 1 -240th. 

A. aculeata. — Lorica hemispherical, though often mis-shapen and 
spinous at the margin. It is formed of short spicula, and is of a 
yellowish colour. The spines sometimes issue from only one-half of 
the margin of the shell, or shield-like lorica ; the shell is not readily 
desti'oyed by heat. Fig. 92 represents one of these creatures with 
the projecting spines, and the large round opening in the lorica. 
Fig. 93 represents another creatui-e with three spines projecting from 
its lorica, and a single variable process issuing from the under side ; 
the digestive cells may also be seen. Fig. 94 shews an empty de- 
formed lorica. Diameter of lorica 1-2 10th. 

A. dentata. — Lorica membranous and homogeneous ; of an hemis- 
pherical or polygonal form, having the margin dentated ; colour 
yellowish or greenish. Foimd amongst conferva. Size 1 -570th to 
1 -240th. 

A. (?) hyalina. — Lorica membranous, smooth, and approaching to 
globular, smaller than the preceding ; colourless. Foimd in matter 
deposited by water, along with Cyphidium awreolum, &c. Size 
1-1 150th to 1-5 70th. 

A. Americana. — oblong ; aperture small, round, not in the median 
line. 

A. constricta. — Lorica ovate ; sHghtly contracted about the foramen, 
\\'hieli is very large and to one side. 



212 DESCRIPTION OF {Polt/gasiHca. 

Akcella disphcera. — Oblong ; almost divided into two by a central 
constriction ; one-half nearly occupied by tlie large foramen. 

A. econiis. — large ; hemispherical, not areolar ; aperture roimd, 
large, placed to one side, entire. 

A. limata. — Lorica sub-globose, large ; Avith a large semi-lunar 
opening, seated to one side. 

A. Nidus-pendulus. — ovate ; oblong, hyaline, loosely areolated ; 
aperture in front, oblong, margin entire. 

A. pileus. — Lorica hemispherical, depressed, reddish, minutely and 
elegantly areolar ; apcrtui'c centi'al, circular. 

A. ? glolulus. — Sub-globose ; with loosely reticular lines, appearing 
granular; aperture large, simple. Diameter l-730th. Found on 
moss at Berlin, Potsdam, &c. 

A. granulata. — Oblong; hyaline. Has the habit and size of A. 
hyalina with a granular instead of a smooth surface. Length 1 -940th. 
On moss in Hercynia, &c. 

A. caudicola. — Lorica ovate, oblong, rounded at each end, hyaline, 
very delicately hispid, not areolar ; aperture anterior, round, large. 
Length 1 -840th. 'K-eihit oi A. Nidus peridulus. Foimd in Venezuela, 
on roots of plants, such as ferns, &c. 

Genus Cyphidium. — This genus is distinguished by the creatures 
having only one dilated variable ]3rocess, and a lorica of the form of a 
pitcher, with protuberances issuing from it. It forms a connecting 
group between Arcella and Bacillaria, by reason of the sijuple loco- 
motive organ (like a snail's foot), and approaches very closely to the 
group Desynidiece. The lorica is something like a little die or stamp, 
mounted upon a short stem. It is very irregularly formed, having 
protuberances so as to make it appear four-comered ; it is combustible. 
The oi'gan of locomotion is a broad, gelatinous, variable process, with 
smooth edges, resembling in appearance the body of Amceba verrucosa. 
Neither digestive cells or apertures in the lorica have yet been ob- 
served, nor organs of sensation, or of propagation. 

C. aureolum. — Lorica of a cubical form, with protuberances ; process 
colourless. In March, 1835, says Ehi^enberg, "I first observed 
hundreds of these crcatm-es in a glass of water, which had stood 
throughout the winter, in company with some specimens of the 
Micrasterias. I'reviously to discovering tliese, the Amoeba verrucosa 



Atcellina.'] INFrSORTAT. ANIMALCrLHS. - 213^ 

had been abundantlj' generated ; and, after their discovery, ArcdJa 
hyalina. The creatures were inactive, although, with attentive ob- 
serv^ation, they might be seen to change their phiees." Ehrenberg 
only once perceived the locomotive organ of the animalcule, situated 
tmder one corner, upon which it appeared to rest, and that so firmly, 
that six out of the eight protuberances of the die-like loriea were 
visible at the same time. Figs. 95, 96, and 97, represent these 
creatures in different positions. In the second, the gelatinous 
variable process is seen projecting from beneath the loriea ; in the 
other two figures, the loriea only is \'isible. Fig. 98 is a young- 
specimen. Size 1 -570th to l-430th. 

The first four of the ensuing appended genera are from Dujardin, 
the others from Schlumbergcr. (An. des Sciences, Zoologie, 1845.) 

Genus Tkinema. — Shell membranous, but resistant, diaphanous, 
ovoid elongated, narrower in front, with a large oblique orifice 
placed laterally ; expansions filiform, as long as the shell, very thin, 
and but two or three in number, entirely retracted when expansions 
are to be pushed out from another side, and moving the animal 
onward by their contraction. 

T. acinus. = Bifflugia Enchelys. (Ehr.) 

Genus Euglypha. — Shell diaphanous, membranous, resistant, of 
an elongated ovoid form, roimded at one end, terminated at the 
other by a very large truncated orifice, with a dentated margin ; its 
surface marked by eminences or depressions, in regular oblique series ; 
expansions filiform, numerous, simple. 

E. tulerculata. — Loriea striated with rounded tubercles. The ter- 
mination of its expansions are extremely delicate. Length 1 -295th. 
Found in stagnant ponds. 

E. alveolata. — Loriea with regular polygonal depressions in regular 
oblique (spiral) series. Length 1 -290th. 

Genus Gkomia. — Loriea smooth, yellowish brown, membranous 
soft, globular, with a small round opening, from which the very long 
branching expansions proceed, tapering to very fine extremities. 
Found in both salt and fresh water. 

G. oviformis. — Globular, smooth, aperture surrounded by a short 



214 DESCRIPTION OF \JPolyf)astr\ca. 

neck, expansions branching, but slightly anastomotic. Size of shell 
1 -26th to l-13th. Length of expansions one-half. 

Ghomia fluviatilis. — Globular, or ovoid, -without a neck ; expan- 
sions palmate and anastomotic. Diameter 1 -290th to 1 -104th. 

G. hyalma, (Sehlumberger). — Lorica globular or rather ovoid, 
smooth, soft, diaphanous, colourless ; foramen round, with a very 
short neck, formed by a reflection of the lorica ; expansions filiform, 
numerous, very fine, branching and anastomotic. Diameter l-865th 
to 1 -520th. In rivulets. 

"Notwithstanding the absence of colour in the shell, (saysDujar- 
din), I arrange this species in the genus Gromia. In size it also 
differs from the other two species. The lorica being transparent, 
admits to view, some blueish globules, and a large hyaline glandular 
ovoid body, like that in the interior of other diaphanous RMzopodes." 

Genus MiLiOLA. — Lorica calcareous, ovoid, or depressed, having 
but a single opening, consisting of several cells variously disposed. 
Expansions filiform, radiating from the single orifice, which is bifid, 
by the projection into it, on its inner side of a tongue-like process. 

The lorica is compact without pores, and either smooth, or vari- 
ously marked by ribs or striae. Expansions very fine. 

Examples of this genus are very numerous in a fossil state with 
other PolytJialamia, often constituting the chief components of large 
masses of earth. Many of them are also visible to the naked eye. 

Genus Lecqtjeretjsia, (Sehlumberger). — Shell ovo-globular, or 
retort-shaped, rather depressed, membranous, but resistant ; with a 
wide short neck, and circular terminal aperture, giving passage to 
cylindrical, tliick and obtuse expansions. 

This genus approaches Difflugia, (Duj.) in the character of its 
expansions, but the very different form of the shell, and the position 
of the aperture, sufficiently mark the distinction between the two. 

L. Jurassica. — Shell resistant, diaphanous, grey, of a globular 
figure, but rather depressed with a short wide neck. Length about 
1 -250th. Breadth 1-31 5th. 

This beautiful species is met with on aquatic, or other dead plants, 
in many of the lakes of the Jura chain about Nefuchatel. Its 
diaphanous lorica allows its interior soft hyaline and granular body, 
strewn with brown specks, to be seen. 



Acellina.'] inffsokiat, ANiMAtCFLKS. 215 

Genus Ctptioderia. — Lorica membranous, resistant, ovoid elon- 
gated anteriorly, where it is ciu'ved, and constricted in the form of a 
neck ; surface marked by prominent points in oblique rows ; aperture 
circular, obliqiie, expansions very long, filiform, very fine at the 
extremity, and simple or branching. 

The oblique disposition of the rows of points, the obliquity of the 
aperture, and the character of the expansions, bring this genus into 
affinity with Trinema (Duj.); but the interior constriction, forming 
a neck, seems sufficiently distinctive between the two. 

C. margaritacea. — Lorica yellow; the translucent points looking 
like rows of pearls. Processes attain twice the length of the shell. 
Length l-395th. Breadth l-840th to l-408th. Common in the 
water of the Vosgcs with vegetable debris. The fonn of the lorica 
varies ; at one time the neck may be but rudimentaiy ; at another 
the posterior end, instead of being wide and roimdcd, is conti'acted 
suddenly to a truncated apex. 

Genus PsEUDO-DiFFLiTGiA. — Shell membranous, ovoid, or ovo- 
globular, smooth or striped spirally, with a wide round opening, 
whence proceed numerous long, slender expansions, either simple or 
branching. 

This genus is allied to Bifflugia by the form and character of its 
shell, but differs from it in the nature of the expansions. 

P. gracilis. — Shell blueish brown, brittle ; surface, as if beset with 
minute grains of sand, of a more or less elongated ovoid figure, ex- 
pansions filiform, very long. Length 1- 740th to l-465th. Breadth 
1 -890th to 1 -740th. Found near Mulhouse. 

Genus Sphenodeeia. — Shell diaphanous, coloiirless, resistant glo- 
bular, with a flattened wedge-shaped neck, surface marked by 
polygonal depressions, disposed in regular oblique rows ; aperture 
terminal, compressed, almost linear. Expansions filiform, very long 
and attenuated. 

The form of the aperiiu'e and of the neck separate this genus from 
Trinema and Eiiglypha, to which it is allied by the sti-ucture of its 
lorica. 

S. lenta. — Lorica as above described, expansions few, veiy long, 
slender, and simple, or branching. Length 1 -650th to 1 -520th. 
" Of aU the Rhizopodes (says Dujardin) this is the slowest in its 



21(5 t»T'sci!TPTTON Of [Poh/flasfrlM^ 

movements, and its expansions the most difficult to discover. I have 
found it on tufts of moss in marshy rivulets." 

In the internal soft substance, are seen near the posterior end, a 
glandular body and hyaline globules. In moving, the position of 
the shell may be perpendicular, or oblique to the surface of reptation. 
the hexagonal depression are indistinct but large. The shell fracturea 
along the lines of junction between the hexagons. 



Pamilt— BACILLAEIA. 

In re-writing the accoimt of this very extensive and important 
family it will be advisable to retain much of the original text, and to 
present most of the more recently obtained particulars together with 
the various views entertained by authors, as an introduction to each 
section, namely, the 'Desmidiacea and Naviculacea, into which the 
Baeillaria are divided. 

The fii'st observers of this family considered its members animals j 
but the greater number of modem naturalists regai'd them as plants, 
and place them among the minute alga) ; hence it is, that we stand 
indebted to the botanist for much of oiu' loiowledge of their forms 
and localities. Again, some of the genera arc considered by philo- 
sophers to be the connecting links between the animal and vegetable 
kingdoms. 

Although, as before observed, there does not exist any distinct line 
of demarcation to separate animals from plants, similar to that which 
exists between organic and inorganic bodies, yet, with respect to the 
animal or vegetable nature of the Baeillaria, after careful examination 
of the proofs oifered on both sides of the question, it appears to me 
that their position among organized beings, stands at present as 
follows : — 

Vcgrtable Algse. 

Desmidieae. 



Baeillaria. 

Na\'iculacea. 



! 



Animal , Polygastrica. 

Professor Bailey, of New York, in his recent valuable "Microsco- 
pical Observations made in South Carolina, Georgia and Florida," 



SucUlaria.] infusorial animalcules. 217 

appends to one of his tables of fossil organisms discovered by him, the 
following excellent remarks : — 

" I have separated the Besmidiem and Dintomaeeee, (Naviculacea), 
from the Infusoria, and I have done so, because many distinguished 
observers now consider these groups as decidedly belonging to the 
vegetable kingdom. A\Tiile I believe that no accurate line of sepa- 
ration can be di-awn between vegetables and animals, I am yet dis- 
posed to consider the Desmidiea^ from the sum of all their characters 
as most ueaiiy allied to the admitted vegetables, while the Biato- 
macea, notwithstanding Thwaite's interesting observations on their 
conjugation, still seem to me, as they have always done, to be true 
animals. There is such apparent volition in their movements, such 
an abundance of nitrogen in the composition of their soft parts, and 
such resemblances between the stipitate Gomphoncmatce, and some of 
the Vorticelldii, that I should still be disposed to class them as ani- 
mals, even if Ehxenberg's observations of the retractile threads and 
snail-like feet of some of the Navicxdce should not be confirmed." 

Ehrenberg, (whose skill and practice in the use of the microscope 
has been very great,) affu'ms that all the members of the family 
BaciUaria are decidedly animal, and characterizes them as compre- 
hending all animalcules, distinctly or apparently polygastric, destitute 
of alimentary canal ; the body furnished with variable undivided 
processes, and covered by a lorica or shell. While undergoing self- 
division they appear connected together, as it were, by a percuiTcnt 
thread, so that they form chain-like or tabular groups. The lorica 
of each animalcule has one or more openings, and at the places where 
these creatures are connected together, the union is effected by means 
of soft processes protruding thi-ough these openings. Excepting 
Naticula, and one or two other genera, they never separate spon- 
taneously into single individuals, but always adhere, forming polypi- 
like concatenated masses of greater or less extent ; hence it is that 
the term imperfect self-division has been appKed to their mode of 
propagation. 

This family is of vast importance in. a geological point of view, 
and the valuable obser\^ations of Professor Bailey, on the fossil forms 
of America, are of deep interest; indeed, the laboiu^s of that eminent 

a 



218 DKSCRIPTTOW OF \ Poh/rffifff'rif'a. 

naturalist in this department has far sui'passed those of any european 
observer, if we except Ehrenberg, (See section Navkulaceci). 

The composition of the lorica or shell in this family is various, 
and may be separated into tAvo kinds ; the fii-st containing silica, 
either pure or in combination with the oxide of iron ; forming a 
silicate of iron ; the second, those in which silica is entirely absent, 
when the lorica has a membranous or parchment-like (structure) 
texture. It is remarkable that in no case has lime been foimd to 
enter into their composition. In some genera the lorica is surrounded 
by a soft gelatinous variously-fonned envelope or induvium. The 
shape of the lorica is various, but such as entu'ely to inclose the in- 
ternal organic portion, except the parts where it is united with 
others ; hence it is termed urceolate. The lorica is composed of two 
or more shells, or pieces, termed valves, which are usually dish or 
cup-shaped, and often fluted (striated) or grooved. Those in which 
silica enters iuto the composition have usually a round or a prismatic 
four- sided figure, while, in the non- siliceous, they are generally flat, 
with three to five sides. 

Of the internal organization of these creatures little is known, owing 
to their opacity, and the structiu'e of the enveloping lorica. In many, 
however, lai'ge ti'ansparent variable vesicles are seen among the mass 
of coloured granules which occupy the greater part of the lorica. 
These vesicles are considered by Ehrenberg to be digestive cells, and 
the coloiu'ed mass (the ehlorophyl of botanists,) ova. In some 
species, as soon as the coloured ova are protruded, the parent dies ; 
in others, the ova form a Monad-like mass, fi'om which when ma- 
tiu'ed the parent separates ; hence, says Ehrenberg, has arisen the 
opinion of the transition of animals into plants. In Micrasterias, 
Anthrodesmus, and one or two other genera, says Ehrenberg, male 
reproductive structiu-es are visible, but no trace of a sensitive system 
has been discovered. 

From the clustering nature of this sluggish family, and the rigidity 
of thcu' coveiings, they resemble the confervoid Alga?, and other 
minute vegetable fonns, and are hence confounded with them ; but 
in their mode of propagation a distinction may be recognized. In 
the Bacillaria, the self- division is always longitudinal, so that the 



Bacillaiia.} infttsoeial animalcules. 219 

conferva-like forms are not composed of long slender and filiform 
bodies, like plants, but of short and broad filiform portions Some- 
times tlie self-division is from back to front, or from side to side ; the 
single creatures are then band-like, or half-moon-shaped. 

In Navicida, Ehrenberg has described a locomotive organ possessing 
the power of moving in any direction, and accommodating itself to 
any form, similar to that cnrious muscular organ, the tongue, in 
animals, or to the foot-like process of snails. 

The shells of these creatui'es are often sculptured with deep 
flutings ; where this occurs, the inside of the shell is not always 
smooth, but follows the form of the exterior : thus the strength is 
gi'eatly increased, while the quantity of solid material employed in 
their construction is not augmented. The flutings (striae) in the 
living specimens being filled with coloured matter, are discerned 
with difficulty, and hence they are almost unknown. In the fossil 
state, the shells are empty, and then the flutings and other indenta- 
tions become distinctly Adsible. I have, therefore, in the engravings 
illustrating this family, selected dra-ndngs of several in both states, 
so that the reader may form a clear conception of their true characters, 
while the interest attached to the family generally is so great, and 
we possess so few drawings of its various species, that I have been 
induced to extend the number of illustrations considerably. The 
order of their arrangement differs from that given in the plates of Die 
Infusionsthierchen ; in that work the species and genera are placed in 
plates indiscriminately, and no regular aiTangement is observed. As 
some fossil specimens have been discovered since Ehrenberg' s great 
work appeared, I have had drawings of the finest I could procure, 
made for me ; some of them are the last productions of my fiiend, 
the late E. Bauer, Esq. ; so that the numerous illustrations of this 
family, whether the members be considered as animal or vegetable, 
will, I believe, be highly acceptable both to the botanist and 
zoologist. 

The remarks in the last paragraph refer to the engravings of the 
first edition, all of which are retained in the present one, while 
most of the mimerous figures in Plates 13 to 20, are additional illus- 
trations of the Bacillaria. 

In this family we are not only presented with the simplest foiTns 

a 2 



220 DESCETPTioTf OF \^Po7'i/gasfrica. 

of organic matter, but, fi-om their numbers and the indestructibility 
of their shells, they have led to many important discoveries. The 
large masses of meteoric paper which fell in 1686 have recently 
been shown to consist mainly of their coverings, while several hun- 
di'ed square feet of a flannel-like substance, lately foimd near Sabor, 
in Silesia, after an inundation, was composed of Flagilaria, Navicula, 
Crypfomonas, and Chsterina, interwoven with Conferva livularis. 

As microscopic objects, the markings of the fossil species are 
highly interesting ; and when mounted as opaque objects, a verifi- 
cation of the structure of their shell is clearly demonstrated. 

Ehrenberg's primary division of this family is into single and 
double-loricated animalcules ; the genera comprised in the first being 
again separated into those which are attached, by a pedicle or stalk, 
and those which are destitute of siich appendage, or free. 



SacUlayia.l 



INFUSORI.VL ANIMALCULES. 



221 



The fm-tlicT distribution of the genera, by Ehi-enberg, will be seen in 
the fbUowing table ; — 



One 

valved. 
{Desiiii- 
diacea). 



prism 



globulai 



smooth . 



flat 



Two or 

more 

valved. < 

Navicii- 

lacea. 



. prismatic < 



r three-sided Desmidium. 

four-sided Staurastnim. 

five-sided Pentasterias. 

clusters moniliform Tessararthra. 

do. herry-like Sphaerastrum. 

spinous Xanthidium. 

/ compressed or lying to- 
band-like I ^•5*^^'' Arthrodcsmus. 

' united by serritures Odoutella. 

f many in each plate or disc. . Micrasteiias. 

plate or disc-like. ... •^ two ditto Euastrum. 

Lsing-le and disc-like Microthcca. 

r spherical, simple Pyxidicula. 

I 1 -celled, articulated filiform Gallionella. 

( many celled, concentrically Actiuocyclus. 

six openings to lorica . . Navicula. 

four ditto Eunotia. 

one ditto Coeconeis. 

^ waud-like Bacillaria. 



forming coral-like 
clusters 



self-division complete 
never band-like 



division incomplete, 

forming-band-like < 

clusters 



joiuted 



( plate-like Tessella. 






jointless f ^™'^® straight . . Fragilaria. 

(fragilej (bands spiral Meridion. 

single individuals broader than long , Isthmia. 

formed as a wand (prism-shaped) Syuedra. 

formed as a wedge Podosphenia. 



^1 

O J3 



stalkless, 
sessile 



stalked ■< 



Covered with an amorphous 
mass of gelatine 



'°< 



Covered with membranous or J 
gelatinous tubes \ 



1 dichotomous by long. div. . Gomphonema. 

wedge-shaped ' 

( whorled or radiating by do. Echinella. 

lance-shaped, attachment dii-ect , Cocconema. 

banner-like ( ^ central opeiiiiig Achnauthes, 

attachment oblique ) ' . , • ^.^ • . ,, 

L ^ ^ no central opening Stnatclla. 

scattered FrustuUa. 

connected in a ring-like manner Syncyclia. 

rspiculi straight Nauuema. 

C tubes simply branched-< 



ditto aRgrcsatcd, 
bundJe-like 



, ditto crooked Gloconeina. 

f slit like a bimch .Schizoncma. 

Ibranched like a tree Micromcga. 



222 DEscEiFTioN OF {Tolygastrica. 

The riews of Ehrenberg on the Bacilla/ria, have, from their first 
promulgation, had many objectors, whose arguments were well 
brought together by Dr. Meyen, and are as follows : — 

" Professor Ehrenberg has described and represented, in his great 
work upon the Infusoria, a very considerable number of organized 
bodies, looked upon by botanists as belonging to the vegetable 
kingdom. In these representations, naturalists have been able to 
attaia what has been long desh-able ; for, although in respect to the 
more highly developed and complete vegetable beings, the truest deli- 
neations are indispensably necessary at the present day ; it is much 
more requisite that every one of these lower and microscopic organisms 
should be laid before us in the same tangible manner. To the syste- 
matist, it is of no import whether these beings are represented as 
I)lants or animals, for one thing is certain — they will always remain 
ivhat they are. In this work, Ehi-enberg has not only given syste- 
matic descriptions of these questionable animals or plants, but his 
own observations, coupled with those of his predecessors, upon the 
nature of these bodies, are found copiously detailed. This, however, 
is apparent ; all the facts known upon the subject are interpreted in 
a manner as if these creations were undoubtedly animals, whilst the 
same facts would indicate quite a diiferent signification if we pro- 
coeltd upon the supposition that they were nothing but plants. It 
now becomes a question as to which view is right, or whether we are 
able to prove positively cither one or the other. The subject, how- 
ever, is one of high importance, and we shall say a few words upon 
it, bringing forward those genera as illustrations of the subject, 
which, according to my own opinion, are decidedly composed of plants. 
The first little plant we find described and represented in Ehi'en- 
berg's work is Goniwn (?) tranquillum (E.) This I discovered in 
1828, gave a representation of it, and afterwards named it Merismo- 
pedia imnctata. Ehrenberg himself has observed nothing animal with 
respect to this j^lant, which belongs to the Ulvaceae, and distinguishes 
itself remarkably by its continual regular self-di\dsion. The mem- 
bei's of the genus Closterium belong just as decidedly to the vegetable 
kingdom as does the Gonium ; but the following reasons are adduced 
by Ehrenberg as proofs of their animal organization. They possess 
voluntary motion ; they have openings at the extremity ; they possess 



Ji'icilhvia.'] TNFrsoin\L animalcules. 223 

continually moving cAen protruding organs immediately behind the 
openings, and they are endowed with transverse self-division. Eut 
all plants, says EluTnberg, which are endowed with vohmtary 
motion, open oiificcs, feet, and self-division, we may look upon as 
animals, without waiting to see them eat. That this last resolution 
is correct, no doubt all botanists will accede to ; but the follomng 
considerations are those which incline to the opinion of the vegetable 
nature of the Clostcrina. The sti-uctiu-e of the Closterina is evi- 
dently that of the Conferva, as well as the formation of their spores 
or seeds, and the development of them. The existence of amylum 
(starch) within the Closterina is a stiiking proof of their vegetable 
nature. They are likewise destitute of feet, for what Ehrenberg 
took for these appendages are self-moveable molecules, as are seen in 
CHosterium trahecula, to the number of 500 or 600, or more, and 
filling a canal rimning along the whole length of the plant. The 
fiinction of these bodies it is very difficult to determine ; but they 
are to be found in very many Conferva, and are perhaps to be likened 
to the spermatic animalcules of plants. 

" Under the great family BaciJlaria, Elircnberg has brought 
thirty-five to tliirty-six genera ; but which may be more properly 
divided into two separate families — the family of the true BacUlaria, 
and that of the Besmidiaeea. This last family has already been firmly 
settled by Menegheni, and includes those irvie Algae, concerning whose 
nature there can be no doubt. To the ti'ue Algae belong the fol- 
lowing genera of Ehrenberg' s BacUlaria : — Besmidium Ag. ; Sfauras- 
tnun, Mey. ; Pentasterias, Ehr. ; Sphaerastrum, Mey. ; Xanthidium, 
Ehr. ; Scenedesmus, Mey. ; Odontella, Ag. ; Pediastrum, Mey. {Mi- 
crasterias, Ag.) ; and EtMstrmn, Ehr. In all these genera, nothing 
has yet been observed which can be adduced as evidences of their 
animal nature. Actual motion, arising from internal causes, I saw 
only in Sphaerastrum ; and the slight movement, supposed to have 
been observed in some of the genera, is certainly of the same 
description as that of some Conferva, which sometimes vegetate far 
below, at other times upon, the surface of water ; but this elevation 
from the deep is generally connected Avith visible evolution of gaseous 
matter. The increa,se by self-division occurs in all these genera ; 
this process is looked upon Ity Ehrenberg as one of the strongest and 



224 DESCRIPTION OF [Poly gastric a. 

most decisive characters of animal natxu'e ; but I have elsewhere 
proved, in the most satisfactory manner, that self-division is very- 
common, both in the lowest plants as well as in the elementary 
organs of the more highly developed ones. The little vesicles 
endowed with molecular motion, seen in the genus Euastrum are 
completely identical with those observed in Closterium and the Con- 
ferva, and. I see no good reason why Closterium should not be placed 
near JEuastrum. The green corpuscles observed withia the cells of 
most of the Desmidiacea are similar to the green corj^uscles found in 
the cells of the Conferva ; and though Ehrenberg may consider them 
as ova, I have observed their develojjment in spores, and in several 
genera have distiactly seen that they contained amylum, and some- 
times that they were even entirely composed of it. 

" The second section of the BaciUaria includes the true BaciUaria, 
and are indicated by the term Kaviculacea ; here are to be found 
those numerous forms, which, from their occuiTence in a fossil state, 
have lately given rise to such a great degree of interest, and which 
Ehrenberg, and many other naturalists, regard as undoubtedly 
belonging to the animal kingdom. 

'* The reasons adduced for such belief, however, are so weak, that 
the conclusions deduced from them are yet, for the most pai't, very 
doubtful. 

"The movement of the BaciUaria, however free it may be, is by 
no means so free and active as that of the spores of the AJgae and the 
spennatic animalcules, which are plants, or at least parts of plants, 
and the motion is no very positive ground for the behef of their animal 
condition. The common mode of propagation, seen in BaciUaria, is 
that of self-division, which is also proper to the cells of the higher 
plants ; the increase by spores or ova ensues but rarely. The fonn, 
structure, and especially the habitus of the BaciUaria are evidently 
of that kind to lead one to consider them as plants ; but the following 
circumstance, which is of very considerable interest, militates against 
it. In many Nmiculm, it is observed that the molecules, such as of 
indigo or carmine, &c., in the same solution, that may come into 
contact with the surface of the body of the creature, are immediately 
set in motion, and often run along with considerable rapidity by the 
side of the body, and even turn and run in an opposite direction. 



Bac'illar'ia.'\ iKFrsoniAL animalci^les. 225 

This remarkable appearance has its cause, perhaps, in the existence 
of numerous delicate cilia, which are present over the surface of the 
creature, and giving rise to the motion. 

"With om' present instruments we cannot take cognizance of 
these organs ; but when making use of a very high power, a sort 
of transparent narrow zone is observed around the bodies of the 
Bacilhria. 

"Lastly, Ehrenberg adduces another observation as satisfactorily 
proving the animal nature of the Bacillaria. They sometimes 
receive colouring matter, which fills the vesicles looked upon by him 
as stomachs. This last statement appears at least very striking, 
but the way in which the case stands seems to be somewhat different. 
In the first place, I can see no stomach sacs in the Navicidce, and 
never observed in the living and moving Bacillaria the colouring 
matter received at one extremity and carried towards the centre, 
where these stomach sacs should lie, whilst in the Infusoria such 
observations are easy ; on the other hand, it is not rarely found, 
especially T\ith the larger living animalcules, that the molecules of 
the coloui'ing matter employed, lie upon the middle of the broad 
ventral surface, from wliich it appears as if the colouiing material 
was really existing internally ; but if a glass plate is placed upon it, 
and then properly removed, the globule of colom'ing matter may be 
taken away. The imprejudiced reader must then see that much 
obsen-ation is yet wanting ere we can hope satisfactorily to determine 
that the Bacillaria are truly animals ; and how closely plants and 
animals border upon each other is recognizable in the spermatic 
animalcules of the lower plants, and the spermatic animalcules of 
animals." (Jahresbericht, Berlin, 1839.) 

Since the date of Dr. Meyen's paper, much has been done to 
augment our knowledge of the Bacillaria , and, in the opinion of 
most natui'alists, also to indicate yet more their affinity with plants. 

The phenemenon of conjugation, so admirably investigated and 
illustrated by IMr. Thwaites, is regarded as particularly indicative of 
the vegetable nature of Bacillaria. In the Desmicliacea, the mode of 
conjugation is the counterpart of that in the Zygnemeoi, (a tribe of 
AlgceJ, producing a characteristic sporangium, but in the Diatomacea, 



226 DESCRIPTION OF [^Poli/gastnca. 

though the conjugation simi^ly is analogous, yet the produced (spo- 
rangia have no proper characteristics, as they resemble the fronds 
producing them, save in their larger dimensions. This variation, 
M. Thuret contends, renders the phenomena of conjugation inde- 
cisive of the vegetable character of the Diatomea, " for it is clearly 
not here a mode of reproduction, — it is only a second mode of multi- 
plication of fiiisttJes, veiy cmious, and very abnormal." 

But a still more decisive objection to considering conjugation a 
proof of vegetable organization, is to be found in the recent disco- 
very of Siebold, that that process is met T\dth in the animal Idngdom, 
and that he has witnessed it in Diplozoon paradoxum, and in Actino- 
fhrys Sol : the former an JEnfozoon, previously regarded as a single 
animal, but in fact a conjugated state of a Parasite, known as the 
Diporpa ; the latter one of the Infusoria. 

A tliii'd objection to the argument that conjugation is favoiu'able to 
these organisms being Algce, is that the higher kinds of AlgcR do 
not conjugate. It would therefore follow if we consider them as AlgcB, 
that the lower tribes of these plants require a renewal of the siDennatic 
force, while the higher ones do not, which would be contrary to all 
our ideas of physiological laws. 

The notion in'opounded by Ehrenberg, that the granules in the 
interior of Bacillaria — including the Chsterina, are ova, has not met 
with support from the observations of other naturalists. In Clos- 
terium a circulation of the granidar contents, involving also many 
of the stomach sacs of Ehrenberg, has been witnessed by most 
microscopists : and in one of the Biatomece, supposed to be a species 
of Navicula, Niigeli says, " I observed a pretty rapid cu'culation of 
the granular contents, the granules passing jfrom the nucleus out- 
wards along the edges, and back again to the former." (Ray Society, 
1845. p. 221.) 

The occurrence of this phenomena is adverse to the opinions of 
the internal animal organization, supposed by Ehrenberg ; whilst it 
at the same time favours the hyi)othesis of the vegetable nature of 
these organisms, the circulation being similar to that so common in 
vegetable ceUs, and the cii'culating gTanules and vesicles, resembling 
those of various confervas, and minute Alcjm. (See Introduction to 
Desmidiacea and Naviculacea.J 



Bacillaria.'] infusorial animalcules, 227 

The primaiy divisiou of Bacillaria, adopted by Ehrenborg, uud 
based on the circumstance of the presence or absence of a gelatinous 
indu-sdum about or upon the true lorica) or frastules is faidty, inas- 
much as this gelatinous envelope is met wdth in various Besmidiacea 
and Namculacea in the adidt state, and generally in all forms during 
the process of conjugation, as a temporaiy production. "Where, 
however, the gelatinous mass plays a more important part, forms a 
nidus (matrix) for very numerous frustules, and is built up in a cer- 
tain, defixdte manner, producing a chai'acteristic thallus — expanded 
frond, it waiTants the separation of such compound organisms from 
solitary, or merely concatenated forms, and their grouping together 
as a subsection. 

The distribution of those Bacillaria, having a ' simple loriea,' into 
three groups, as made by Ehrenberg (see table page) is not generally 
followed : for most naturalists are indisposed to assign so high a 
distinctive value to the fact of the attachment of the loricee, as is 
done by Ehrenberg, in the construction of the group Echinellea. 
Indeed the attachment of a frustule, or chain of fi-ustules, appears 
inconstant, and several of the genera enumerated by Ehrenberg as 
free, subsequent obsei-vations have proved to occxu- also attached. 

The prevailing plan is to make two sections, or families : viz., 
1. Besmidiacea or Besmidiecs. 2. NavicuJacea; the latter including 
the EcliimUea, and the organisms with a double * loriea' the Bacernata 
of Ehrenberg. 

The Naviculacea are sometimes called, Biatomacea, Biatomece, and 
CymheUece. 

Mr. Harvey, in his Manual of British Marine Algoe, considers the 
Biatomacea and Besmidiacea as well marked sub-orders, or proper 
orders of a common alliance — the Chlorospermece, or green Algae. 
Mr. Ralfs considers that the Besmtdiece can no longer be united with 
the Biatomece in one family — and gives the follomng distinctions : 
" The cell in the Besmidiece consists of two valves united by a central 
suture, and, during division, the new formed portions are interposed 
between these valves. The Besmidiece are membranous, or should a 
few species contain silica, it is not present in sufficient quantity to 
interfere with their flexibility. They rarely have acute angles, and 
are seldom (if ever) rectangular. They are often deeply incised or 



228 DESCRIPTION OF \_Poli/ffastrica. 

lobcd, warted or spinous. The internal matter is of a herbaceous 
green coloui-, and starch vesicles abound in the mature cell. They 
couple and form either orbicular or quadrate seed-like bodies, and are 
remarkable for the resistance which they oppose to decomposition. 

*' In all these respects they diifcr from Diatomacca. In the latter, 
each fnistule consists of thi-ee pieces, one central and ring-like, or 
continuous all round ; and the others lateral. The division is com- 
pleted by the fonnation of new portions within the enlai'ged central 
piece, which then falls off, or else by a new septum arising at the 
centre ; but I believe that, in every case, the separation commences 
internally before it extends to the covering. Their coverings, with 
very few exceptions, are siliceous, withstand the actions of fire and 
acids, and may be broken but not bent ; the frustules arc often 
rectangular in form, are never warted, and scarcely ever spinous. 
Their internal matter is usually brown when recent ; and, although 
some species are greenish, or become green after they are gathered, 
none are of a truly herbaceous colour. Their vesicles bear some 
resemblance to those in the Besmidieee, but they are of a yellower 
colour, and no starch has been detected in them. Some of them 
have been seen to conjugate, but their sporangia are elongated and in 
pairs, and the internal matter is similar to that of the frustules." 
(British Desmidiese, page 20.) 

In the following pages we have so far departed from Ehrenberg's 
aiTangement as to include the Closterina with the Desmidiece, in 
accordance mth the now universally received views of their affini- 
ties. Moreover, we have excluded the appended and doubtful group, 
Acineta, according to the opinion of Ehrenberg liimself, as expressed 
subsequently to the publication of his systematic work. 

The particular details of the organization of the Desmidiaeea and 
Navicuhcea, are entered into at the commencement of each of those 
sections ; those relating to the Ecliinellea, presenting nothing special, 
are represented in the account of the Navicidacea. Indeed, in our 
opinion, the section EcMnelha should be merged, as is generally done 
in that of the Naviculacea, but, as we profess generally to foUow the 
system of Ehrenberg, we have thought it right to retain it. 



Desmidieic.'] inp'usorial animalcut.es. 229 



SeCTIOI^ I. DESJrrDIACEA. 

This is one of tlie sections into which Ehrenberg divides his girat 
family Bacillaria ; and it agi'ces mainly with the family Desmidiea 
of other authors. Elu'enberg elevates the Closteria to the rank of a 
family, — taking position between Vibrionia and Astasicc ; which, 
however, in the systems of natiu^alists, have only the value of a 
genus. The alliance set up by Ehrenberg for the Closteria, is now 
considered imtenable, whilst theu' affinity with BesmidiecB is as 
generally admitted. We feel ourselves therefore, wan-anted to 
dej^art so far fi'om following Ehrenberg' s arrangement, as to include 
Closterkon among the genera of Besmidiece. ; but have already given 
the characters of the family in its proper place. (See page 179.) 

Eecent researches, and more especially those of Mi-. Ralfs, have 
so much added to our knowledge of these most beautiful organisms — 
the Besmidiece, that much of Ehi-enberg's account of them has become 
obsolete, and cannot be put forward as a fair representation of the 
present state of science. This circumstance, coupled with that of 
the almost impossibility of engrafting the newly discovered genera 
and species into the system of Ehrenberg, — so greatly influenced as 
that is by his views of the animal organization of the Besmidiece, has 
induced us to employ the systematic an-angement of those beings, as 
given by Mr. Ealfs, in his recent admirable Monograph on the 
" British Desmidicae" it suppljdng, evei-y thing to be desired in pre- 
senting a concise view of this interesting group. We have freely 
employed the generic and specific descriptions of that able naturalist. 
To attempt an independent account, would imply a more intimate 
and perfect acquaintance with the Besmidiece, than that possessed by 
one who has so successfully made them a sjDecial study. The present 
section may be consequently regarded as containing an epitome of 
Mr. Ealfs Monograph, although the researches of other naturalists 
are incorporated, and some new genera and species added. 

Those who would acquire a complete knowledge of the Besmidiece, 



230 DESCRIPTION OF [Pof^fjctsfrica. 

and who would work at them independently, should obtain Mr. 
Ealfs' book, in which cvcrj^ British species is described and figured, 
its special localities named, and many further details given, such as 
can be admitted only in a Monagraj^h. 

Before entering upon the Demnidiacea, the reader M-ill do well to 
examine the different drawings, illustrative of them given in Plate 1 . 
f. 63 to 67; P. 2. f. 99 to 123; P. 13. f. 1 to 44; P. 18. f. 10 
to 19. 

" The Desmidiem are of an herbaceous green coloui" ; a few only of 
the Closteria have the rigid integument coloui-ed, but in all, the 
internal matter is green. They inliabit fresh water. 

Their most distinctive character is that " Each cell or joint, con- 
sists of two sjTumetrical valves or segments, and the sutm^c or line 
of junction is in general well marked ; in a few instances, however, 
as in Scenedesmus, it is determined principally by analogy. In 
Pediastrum, its situation is shewm by a more or less evident notch 
on the outer side, but no separation has been noticed. In the other 
genera the suture eventually opens and allows the escape of the con- 
tents, and it is indicated by either a ti'ansverse line or a pale band, 
and usually also by a constriction." An uninterrupted gradation 
may be traced from species in which these characters are incon- 
spicuous to those in which they are fully developed : — from Clos- 
terium, in which there is no constriction to Bpltarozomia, Micras- 
terias, and other genera, where the constriction is so deep that the 
segments appear like distinct cells, connected by a mere cord. By 
Ehrenberg, indeed, such forms were regarded as binate cells, but 
Ml'. Ralfs for several reasons, concludes that each bipartite frond is a 
distinct, simple cell, merely constiicted. 

The Besmideoi multiplying by repeated tranverse division ; the 
nature of which is well seen in the compressed and deeply constricted 
cells of Eumtrum. Here, as the connecting portion is so small, and 
necessarily produces the new segments, which cannot arise from a 
broader base than its opening, these are at first very minute. 
" The segments are separated by the elongation of the connecting 
tube, which is converted into two roundish hyahne lobules. These 
lobides increase in size, acquu'e colour, and gradually put on the 
appearance of the old portions. Of course, as they increase, the 



Desm'lihcfP.'] INFrSORT.VL ANTMALrri.F.S. 231. 

original segments are piished fiirtlier asunder, and at length are 
disconnected, each taking with it a new segment, to sui)ply the place 
of that from which it has separated." 

"It is curious to trace the development of the new portions. 
At first they are devoid of colour, and have much the appearance of 
condensed gelatine, but as they increase in size, the internal fluid 
acquii-es a green tint, at first very faint, but soon becoming darker ; 
at length it assumes a granidar state. At the same time the new segments 
increase in size, and obtain their normal figuj'e ; the covering in some 
species shows the presence of puncta or granules ; and lastly, in 
Xanthidium and Staurastn'um, the spines and processes make their 
appearance, beginning as mere tubercles, and then lengthening until 
they attain their perfect form and size ; but complete separation often 
occurs before the whole procees is completed. This singular process 
is repeated again and again, so that the older segments are united 
successively, as it were, with many generations. In SjjJiarozosma the 
same changes take place, but the cells continue linked together, and 
a filament is formed, which elongates more and more rapidly as the 
joints increase in number. This continued multiplication has its 
limits ; the segments gradually enlarge whilst they divide, and at 
length the plant ceases to grow, the division of the cell is no longer 
repeated ; the internal matter changes its appearance, increases in 
density, and contains starch granules, which soon become numerous; 
the reproductive granules are perfected, and the individual perishes. 
In a filament the two oldest segments are found at its opposite 
extremities; for so long as the joints di'vo.de they are necessarily 
separated further and further from each other. Whilst this process 
is in progress the filament in Sjjharozosma, consists of segments of 
all sizes ; but after it has reached maturity there is little inequality 
between them, except in some of the last formed segments which 
are permanently smaller. The case is the same with those genera, 
in which the separation of the cells is complete. It is obvious that, 
from the beginning, the new segment must have the same breadth 
as the junction from which it springs ; and when consequently, the 
junction is as broad as the cell, — /. e. where the valves are united by 
their entire breadth, the new portion is of equal width, and so can 
be distinguished only by other means than their size." 



232 DESCRIPTION OP {TdhjcjasiAca, 

"Tlie spontaneous division of the frond is included by some 
writers amongst tlie modes of reproduction, but is rightly the manner 
only in which the indi^-idual plant grows, since all the cells arrive 
at maturity nearly at the same period, and terminate their existence 
about the same time." *' The Besmidieoi are most probably repro- 
duced only in two modes; one by the escape of the granvdar contents 
of the mature frond, and the other by the formation of sporangia, 
the result of the coupling of the cells." 

"^Tien the cells approach maturity, molecular movements may 
be at times noticed in their contents, precisely like that seen in the 
Confervse, and which has been aptly termed a sicarming. "When re- 
leased by the opening of the sutui'e, the granules still move, but 
more rapidly and to a greater distance. The subsequent histoiy of 
these granules is, I conclude, similar to what has been traced in 
other Algae. Compare with this the observations of M. Thuret, 
which we have appended to the account of Pediastrmn ; for in that 
genus M. Thui-et states that he witnessed the escape of minute new 
fr'onds from the cells of the parent fronds. 

On this supposed mode of propagation by Zoospores, we have the 
advantage of some recent remarks by the Rev. W. Smith : he writes, 
*' another mode of increase, analogous to the propagation by Zoos- 
pores in Hpliaroplea crispa and other Algae, has been assigned to the 
Bemiidiece, and it has been alleged that the endochrome escapes in 
the form of Zoospores, and becomes transformed into new fi-onds. 
M. Morren not only affirms this to be the case, but gives a figau'e 
illustrative of the conversion of these Zoosj)ores, or as he terms them 
^' propagules,'" into new fr'onds. Mr. Ealfs merely observes that the 
escape of the granular contents of the matui'e frond is prohahly one 
mode by which the Desmidiea; are increased. He, however, regards 
the " swarming of the granules" (which I am disposed to regard as 
a disturbance attendant upon the decay of the granular mass) as 
identical with the movement of the Zoospores ; and states that with 
the histoiy of these granules after their escape, he ^xas, altogether 
unacquainted. He afterwards gives a figui-e (British Desmidieae, P. 
27), upon the authority of Mr. Jenner, representing the bursting of 
the sporanguim and the growth of the young fronds from its con- 
tents in Chsterium acerosium, so closely resembling the figiu'e by 



DesmidiecBJ] infcsobial animalcules. 233 

M. MoiTcn (see P. 18, f. 15) of the convei'sion of the propagules of 
C. Ehrcnbergii into young fronds, that I cannot but believe a similar 
phenomeuon to have been noticed by both observers, and am inclined 
to accept the views of Mi-. Jcnner as the correct one, and to regard 
propagation by Zoospores or "propagules" as one nut yet satisfac- 
torily established in the Besmidiece.''^ (Ann. Nat. Hist. 1850, p. 4.) 

" The second mode of reproduction is by coupling {conjiigation), and 
the fonnation of sporangia. A communication is established between 
two cells, and a seed-like mass is formed in the same manner as in 
the Conjugated. (See P. 1 3, figs. 5, 6, and 15.) Tliis is green and granidai- 
at first, but soon becomes of a homogeneous appearance, and of a 
broAvn or even reddish colour. In the family Conjugates, the cells 
conjugate whilst still forming parts of a filament; but in the Besmidiem, 
the filamentous species almost invariably separate into single joints 
before their conjugation, and, in most of the species, the valves of the 
cells become detached after they are emptied of their contents. (See 
the account of Closterium.) In many genera the sporangia remain 
smooth and unaltered ; in others they become granulated, tubercu- 
lated, or spinous ; the spines being either simple or forked at the 
apex. The sporangia I consider capsules ; and this view seems to 
be confirmed by the experience of Mr. Jenner, who states that the 
covering of the sporangium swells ; and a mucus is secreted, in 
which minute fronds appear, and, by their increase, at length rupture 
the attenuated covering. The sporangia are most abundant in spiing 
before the pools dry up. 

" That the orbicular spinous bodies, so frequent in flint, are fossil 
sporangia, cannot be doubtful, when they are compared with figures 
of recent ones. Ehi-enberg describes them as fossil Xanthidia ; but 
the true Xanthidia have compressed, bipartite, and bivalved cells, 
whilst these fossils have globose and entire ones. In all the Desmi- 
diccB, but especially in Closterium and Micrasterias, small compact 
seed-like bodies of a blackish colour are at times met with. Their 
situation is uncertain, and their number varies from one to four. 
In their immediate neighbourhood, the endochrome is wanting, as 
if it had been required to form them, but in the rest of the fr'ond 
it retains its usual colour and appearance. I camiot satisfy my- 
self respectiag the nature of these bodies, but I believe them 

B 



231) DESCRIPTION ov \_Polygasirira, 

eitlier to arise from an unhealthy condition of the plant, or else to 
be parasitic. 

" All the Be&midiecb are gelatinous. In some the mucus is con- 
densed into a distinct and well defined hyaline sheath or covering, 
as in Bidymoprium GrevilUi, and Staurasfrum tumidum ; in others 
it is more attenuated, and the fact that it forms a covering, is dis- 
cerned only by its preventing the contact of the coloured cells. In 
general, its quantity is merely sufficient to hold the fronds together 
in a kind of filmy cloud, which is dispersed by the slightest touch. 
Wlien they are left exposed by the evaporation of the water, this 
mucus becomes denser, and is apparently secreted in larger quantities 
to protect them from the effects of drought. 

" Besides the movement of the granules spoken of, a circulation, 
or rather a rotation of the contents of the cells of Besmidiea may 
occasionally be seen under a careftil adjustment of the microscope," 
(See p. 180.) Mr. Ralfs has witnessed it in Clostermm Lunula, and 
in Penium Digitus. He says, " It seems, at least in the Closterium, 
to be restricted to the space between the mass of endochrome and the 
integument ; for neither Mr. Bowerbank nor myself could detect it 
in the internal parts of the endochrome. The movement, however, 
extends over the whole surface of the endochrome. The circulation 
being canied on between the integument, and the mass of endochrome, 
which is usually brought full into view by the observer, explains the 
difficult}^ experienced in detecting the circulation, except at the 
margins. The motion was very irregular : the fluid flowed at one 
time towards the extremities, and at another in the opposite direction, 
and the intervals between these changes were of uncertain duration. 
Streams,-^ also, though apparently not separated by any partitions, 
flowed side by side in contraiy directions. The currents evidently 
consisted of an homogeneous fluid ; but, from time to time, minute 
granules were detached from the internal mass of endochrome, and 
carried along in the streams for short periods, after which they either 
returned to the quiescent portion, or passed into other ciuTonts. It 
seems to deserve particular notice, that the circulation was not 
interrupted at the suture. The process in Penium Digitus was some- 
what different from that just described." 

Nageli believes in the presence of a nucleus in the Desmidiece, 



Desmidiei^.J infusorial animalcules. 235 

generally. He says, " Arthrodesnms possesses a small colourless 
corpuscle on the wall of the cell, which looks like a nucleolus. 
Etiastnim frequently exhibits, among the green contents, two 
obscure bodies resembling nuclei, always one in each half, when the 
division tlu'ough the middle takes place. These are not attached to 
the cell-membrane, but lie fii'ee in the midst of the cavity ; they 
appear to possess a dark centre (nucleolus ?) and a clear periphery 
(enveloping-layer ?).... In Closterium, a nucleus lies in the centre, 
which possesses a tliick whitish nucleolus within a clear enveloping 
layer. It is coloured bro^\Ti by iodine, and wholly resembles the 
nucleus in Spirogyra.'" Elircnbcrg, who previously noticed these 
nuclei considers them analogous to fecimdating glands. Both na- 
turalists agree as to their probable function, but each gives an 
explanation as they view them, either as plants or as animals. 

Eespecting the nature of the Desmidiem, Mr. Ealfs affirms that 
they have as strong a claim as the Conjugates or PalmellcB can have, 
to rank with the Algse. On the other hand, he considers the proper 
station of the DiatomactB very doubtful. 

Ehrenberg's reasons for placing the Desmidiea in the animal king- 
dom are the following : — That they exert a voluntary motion ; that 
they increase by transverse self- division ; and that the Closteria have 
at their extremities apertures, and protruding organs, continually in 
motion. Although two of these reasons apply only to the genus 
Closterium, Mr. Ealfs will admit that if the Closteria can be proved 
animals, the questions as to the other genera will be decided. As to 
the possession of voluntary motion, he protests against the use of the 
word voluntary as prejudging the question. That the Desmidiem 
move, must be admitted ; but, whilst making this admission, he 
maintains that in the lower tribes of organic Hfe, motion is not an 
indubitable sign of an animal nature. Indeed, Mr. Ealfs and Mr. 
Jenner, have both failed to perceive any actual movement : (see 
Closterina p. 179), and whatever may be the motive power of the 
DesmidiecB, according to those observers, they possess it only in 
common with acknowledged Algae, and in a less degree than either 
the DiatomecB, the Oscillatoria, the sporules of various AlgEe, or 
indeed their own sporules. Ehrenberg considers, that increase by 
voluntary division, is the character which separates animals fiom 

K 2 



236 DESCRIPTION OF [Polycfastrica. 

vegetables, and adduces no other reason for his deijial of the vege- 
table nature of some genera; but the bisection of cells is very 
frequent, if not universal, in the more simple Algse ; and Mr. Ralfs 
is of opinion that the process is identical mth that witnessed in the 
Desmidiece. 

'* I (says Mr. Ralfs) am not in a position either to deny, or to affirm, 
■with confidence, the presence of openings in the extremities of the 
Closteria. It appears to mc, indeed, that in Closterium, there is a 
slight notch, or more usually the rudiment of one, at the apex of the 
s( gments, — a mere indication in short of what is fully developed in 
Tetmemorm and Euastrum. In no instance, can any portion of the 
contents of the cell be forced out from the extremities. On this 
subject, the views of Ehrenberg, and Mr. Dalrymple, are given at 
page 180. Mr. Ralfs has the following remarks upon them. 

"I confess I am unable to refer to any example in other Algse of 
terminal globules, like those present in the Closteria, but neither can 
one be foimd amongst animals ; and if in some respects they have an 
analogy with organs belonging to the latter, in others they agree 
better with vegetable life. The contained granules seem to me to 
differ in no respect, except in position and uninterrupted motion, 
from other granules in the same frond, and, as I have already stated, 
I once saw the motion continue after their escape from the cell, pre- 
cisely as ill other zoospores. Meyen observes that the functions of 
these bodies are very difficult to detenniue, but they are to be foimd 
in very many Confervse, and are perhaps to be likened to the sper- 
matic animalcules of plants. 

"The contraction of the internal membrane of the Closteria, or the 
expulsion of their contents on the appKcation of iodine or other 
re-agents, cannot be relied upon as a satisfactory test for determining 
their nature, for the blandest fluids will, in some cases, occasion 
violent action. From the experiments of Mr. P. Grant, it seems 
that the re-action of a re-agent cannot be predicated with any cer- 
tainty, and that the molecular action is not affected by several strong 
poisons, whilst it yields to other substances less generally dele- 
terious. 

"With regard to the " supposed ova," I fully agree with Meyen, 
that tliey are similar to the green corpuscles found in the cells of 



DesmidieceJ] infusokial animalcules. 237 

Confervfe ; and tlie fact of their containing amylum (starcli) is decisive 
against the notion that they are eggs. 

"Although at first sight it seems to indicate the contrai-y, the 
swanning of the zoospores or granules really affords a strong con- 
firmation of the vegetable nature of the Desmidiece. The same 
phenomenon is very generally observed in the Algae, but no similar 
motion has ever been witnessed in the contents of an animal after 
their cscajje. 

" The presence of starch, first observed by Meyen, seems now gene- 
rally admitted. Mr. Dalrymple, who at first failed to detect it in 
Closteria, afterwards did so in Penium Digitus : and Dr. Bailey, of 
New York, has repeatedly proved its presence in Closterium Trahe- 
cida, as weU as in other species. Mr. Ralfs has repeatedly noted 
the efiiBcts of iodine on many of the Desmidiece ; but has found the 
presence of starch indicated only when granules (the ova of Ehren- 
berg) were present, as the fluid colouring matter always becomes 
brownish. Precisely similar results followed the application of 
iodine in Conjwjata in different stages of growth. In the young cell 
there is no starch, but after its first appearance it contiaues to in- 
crease, and is most plentiful in the sporangium. Of all the facts 
which indicate the vegetable nature of the Desmidiece, the presence 
of starch is tmdoubtedly the most important, since it is the most 
easily subjected to the test of expeiiment. 

" The conjugation of the fi'onds in this family suppKes an equally 
striking fact in proof that it belongs to the vegetable kingdom. 

" As in the Conjugata and other Algae, so in the Desmidiea, a bag or 
cell forms between two individuals, the entire contents of which pass 
out and unite together to form one reproductive body, which, be- 
coming detached, leaves the parent corpuscles altogether empty. (See 
P. 18. figs. 10 to 19.) Such an occiirrence is, I believe, not only un- 
known amongst animals, but is contrary to aU our notions of 
animal propagation. The Desmidiece, moreover, present the several 
variations of form of sporangia, mot with in different genera of 
Algae. 

" That the Desmidiea resist decomposition, exhale oxygen on ex- 
posure to the sun, preserve the purity of water containing them, and, 
when bui'ut, do not emit the peculiar odour so characteristic of 



238 DESCEiPTiON OF {Polygastrica. 

animal combustion, are other facts respecting this family, which, taken 
singly, might have less value, but in their combination furnish a 
most important support to the arguments already adduced. 

" The DesmidiecB I regard then as Algai, allied on the one side to 
Conjugated, by similarity of reproduction, and on the other to the 
PalmelUcB, by the usually complete transverse division, and by the 
presence of gelatine. Indeed, the relation to the latter is so intimate, 
that it is difficult to say to which family some genera belong ; — Some 
species of Scenedesmus may be allowed to have an almost equal claim 
to rank with either." 

An additional exemplification of the affinity of the Desmidiece with 
the Algae, has been recently afforded by detection by Mr. Jenner, 
confirmed by Mr. Ealfs, in a species of Tyndaridea, of evident, 
though faint, longitudinal striae, similar to those in many Closteria. 
Mr. Bowerbank has also pointed out the same appearance in 
Tiresias. 

Owing no doubt to the soft, or but slightly siliceous integument of 
the Desmidiece, hut few forms have been found in a fossU state, 
among such are some species of Closterium and Euastnim, and 
doubtful specimens of Xantkidium. 

In Ehrenberg's system the Desmidiece formed one division of his 
family Bacillaria, the characters of which, are given in the table, at 
page 221. 

The following genera have been established since this table ap- 
peared: namely — Lithodesmium, Eucampia, Asterodictyon, Monactinus, 
Gymno%yga, Dyalotheca, Polysolenia, and Zygoxanthium, The genus 
Hyalotheca is adopted by Mr. Ealfs ; of Eucampia and Lithodesmium 
we have figures ; but the other genera are known to us only by 
name, or by imperfect descriptions. 

Genus Hyalotheca, (Ehr.) — Filaments elongated, cylindrical, 
very gelatinous; joints having either a slight constriction, which 
produces a crenate appearance, or a grooved rim at one end which 
forms a bifid projection on each side. End view circular. 

The filaments are invested with a broad gelatinous sheath ; are 
very fragile in one species, but not so in the other. The cyhndrical 
filament distinguishes this genus from Desmidium and 8ph(tro%osma. 
It has no angular projections, is not twisted, and has always the 



Desmidiece.'] infusoeial animalcules. 23ft 

same apparent breadth, and consequently, in all these respects, differs 
from Did/ymoprium. 

Hyaxotheca dissiliens = Conferva dissiliens, (Smith.) — Filament 
fragile, crenate; a shallow groove round each joint, dividing the en- 
dochrome into two portions. The ti'ansverse view is circular, and 
shows a mucous border of the same form. In this aspect too, the 
endochrome is generally disposed in a stellate manner, with six or 
seven rays, and frequently has a colourless central spot. This plant is 
very fragile, breaking into single joints, each MT.th a perfect mucous 
covering. Conjugation takes place by tubes : sporangia, cii-cular. 
(P. 13. f. 32. 35. ; f. 32 a ti-ansverse view.) 

H. mucosa (Ehr.) — Filament scarcely fragile ; joints not constricted, 
but having at one of the ends a minute bidentate projection on each 
margin, the adjoining end of the next joint being similar. The 
filaments have a very broad mucous sheath. The joints seem to be 
in pairs ; a single one is consequently asymmetrical. 

H. dubia. (Kiitzing.) — Filament without a mucous tube ; joints 
rather broader than long, with two puncta near each margin. 

H. cylindrica. (Ehr.) = Besmidmm cylindricum, (Greville and 
de Brebisson, 1835.) See Did/ymoprium Grevillii. 

Genus Didymopeium. — Filaments elongated, gelatinous, fragile, 
regularly twisted cylindrical, with a bidentate process or angle on 
each side of the joints ; hence the margins of the filament are crenate. 
The twisting of the filament causes it to appear of unequal breadth, 
and the form of its joints to vary according as more or less of the 
angles is seen at the margin. In a transverse view the joints are 
cfrcular or broadly elKptic, with two minute opposite projections, 
formed by the angles. The endochrome is radiate ; its rays from 
foui' to seven. (P. 13. f. 38.) 

Bidymoprium differs from Desmidhim in having only two angles. 
In a transverse view, the latter presents a cell truly angular, irre- 
spective of the bidentate projections, and an endochrome divided into 
a number of rays corresponding with the number of angles ; neither 
of these circumstances occur in Didymoprium. 

The filaments of this genus increase in length, by the repeated 
division of the joints, exactly as in the other genera, the new portions 



240 DESCEIPTION OF \^Polygastrica» 

being formed between the ongiual segments, which in otlier respects 
remain unaltered. 

DiDTMOPEnm Grevillii.^IIyalot'heca eylindrica. (Ehr.) — Sheath dis- 
tinct; joints of the filament broader than long, with a thickened 
border at their junction ; transverse view broadly elliptic. The sheath 
is jointed as well as the filaments. 

In conjugating, it separates into single joints : the joints or cells 
become connected by a narrow process, often remarkable for its 
length, and the contents of one cell pass through it into the other, 
and a sporangium is formed in the same maimer as in many of the 
Conjugate. 

The transfer of the endochrome takes place in a mass. After the 
completion of the process, the empty cell is frequently detached, as 
also occurs in those Conjugates which bear the sporangiimi within 
the cell. 

In a front view, the sporangium is as orbicular as the quadrate 
form of the joint will permit. The mucous covering remains im- 
altered on the joints when they are coupled. 

D. Borreri. — Joints inflated, ban'el-shaped, longer than broad ; 
transverse view cfrcular. Filaments pale green, very slender, their 
mucous sheath wanting or indistinct ; angles of joints bi-crenate. 
On account of the length of the joints, the disposition of the endo- 
chrome in two portions is very distinct. The joints have not a 
thickened border as in B. GreveUii, and the filament separates with 
less facility into single joints. (P. 13, f. 38, 39 ; fig. 38 a transverse 
view). The sporangium is elliptic and lies between the cells which 
remain attached to it. 

Kiitzing suggests that this plant may be identical with the Gym- 
nozyga moniliformis, of Ehi'enberg. 

Genus DESMXDniM. — Filament fragile, elongated, triangular or 
quadrangular, regularly t\\isted ; joints bidentate at the angles. This 
organism is of a pale green colour and slightly opaque ; when dried, 
the British species usually acquire a yellowish appearance, and adhere 
to paper or talc less firmly than plants belonging to allied genera. The 
filaments are regularly twisted, but being triangular or quadrangular, 
two of the bidentate angles of each joint are always visible at the 



Desmldiece.^ infusorial animalcitle3. 241 

margins. The endochrome is divided into linear portions by a pale 
transverse line between the angles. Traces of a mucous sheath may- 
be detected. A transverse view shows that the endochrome has 
thick rays corresponding in niunber with the angles ; these rays are 
frequently cloven. 

Recent specimens are known from other genera by one or two 
dark waved lines passing down the filament, caused by the twisting 
of the angular filament. 

Desjiidium Swartzii. — Triangular, equal, with a single longitudinal, 
waved, dark Hne, formed by the thii'd angle; end view tiiangular, 
with the endochrome three-rayed. Filaments very fragile ; adhere but 
slightly to paper ; twisted. The joints are, in the front view, some- 
what quadi-angular, broader than long, and each angle has two 
minute, slightly angular teeth. The joints are connected by a 
thickened margin, which partly fills the notch formed between them 
b}' the projection of their angles, whence the chain has a pinnatifid 
appearance; transverse view, triangular; angles blunt, and sides 
slightly concave. The segments contain numerous minute granules. 
Length of joint I-2000th to l-1666th. Breadth of filament l-633rd. 

D. quadrangulatum, (Ralf.) — Quadrangular, varying in breadth 
from the twisting of the filament, and having two longitudinal waved 
Hues ; the end view quadi-angular, with the endochrome four-rayed. 
Being quadrilateral, the filament presents two longitudinal lines 
crossing each other obliquely. (P. 13, figs. 37 and 40; f. 40 a 
transverse view.) Length of joint l-1244th. 

D. undulatum . — Joints with four crenatxu'es at each margin. 

The constriction of the joints is marked by slight marginal 
notches, on each side of wliich are two broad crenatui'es; in this 
respect D. undulatum differs from D. Stvartzii. 

D. didymum (Corda.) — Ehrenberg and Meneghni unite D. didymum 
to D. hifidum (Ehr.) which the latter describes as a filamentous 
plant. In D. hifidum, says Corda, there ai'e but two simple projec- 
tions on each margin of a segment, but in D. didymum, the two 
projections themselves present each, two secondary ones. 

D. hifidum (Ehr.) = Staurastrum hifidum (Ralfs.) 

D. orhiculare (Ehr.) = Staurastrum orhiculare (Ralfs.) 

D. hexaccrob (Ehi-.) = Staurastrum tricorne (Ralfs.) 



242 DESCBIPTION OF {Tolycjastrica. 

DESMiDrtm aeuleatum (Ehr.) = Staunistrum aculeatum (Ealfs.) 
D. apiculosum (Ehx.) = Staurastrum muricatum (Ralfs.) 
In a paper published by Ehrenberg in 1840, we have found the 
following described as species of Lesmidium, but the characters 
detailed, lead us to the opinion that they really belong to Staurastrum. 
One of them, indeed, called Besmidium ramosum, has, we observe, 
been identified by Mr. E.alfs as equivalent to his Stav/rastrwn 
sjjongiosum. The others are : — 

D. divergens (Ehr.) — Angles of the sides aculeate, recurved on 
one side, corpuscles binate, divergent ; semilunar on the dorsum ; 
surface smooth. Diameter l-1150th. If a representative of anew 
genus ? 

D. tridens. — ^Angles on the sides acute, long, rostrate, tridentate at 
the apex ; fusiform dorsally ; the entire surface of the centre of the 
disc armed with spines. Diameter 1 -480th. Is allied to D. hexa- 
ceros (Ehr.) 

Genus Aptogonum (Ralfs.) — " Eilament elongated, triangular or 
plane ; joints bicrenate at the margins ; an oval foramen between 
the joints. Endochi-ome bipartite. — It is closely allied to Desmidmm, 
but the large oval foramen between the joints is so remarkable a 
character, that I must concur with Ehrenberg in placing it in a 
separate genus. As, however, Ehrenberg' s name, Odontella, had pre- 
viously been given by Agardh to some DiatomacecB, it became 
necessary to find another name. Elu-enberg included SpJuerotosma 
in his Odontella, but the present genus is essentially distinct from 
Splioerozosma ; the latter has the joints incised or sinuated, and 
gland-like processes at their junctions, and it is merely by the inter- 
position of these processes that the joints are now and then slightly 
separated ; in this genus, on the contrary, the joints have two pro- 
minent teeth at the margins or angles, and the foramen results from 
the excavation or concavity of the joint itself, and not from the 
presence of glands. 

A. Besmidium = Odontella Besmidium (Ehr.) — Joints in the front 
view quadrangular, broader than long; crenatures distinct. lS.o 
sheath. 

Var. (a.) — Filaments triangular, regularly twisted; crenatures 
rounded. 



DesmidiecB.'l infttsorial animalcules. 243 

Var. (b.) — Filaments plane ; crenaturcs shallower and sliglitly 
angular. (P. 2. f. 108.) 

ApTOGONim Baileyi. — Filament not crenated ; joints about equal 
in length and breadth. Filament triangidar ; angles, in end view, 
rounded. 

Genus Sph^eeozosma (Corda.) — Filament plane, fragile; joints 
closely united by means of glandular processes, and deeply divided on 
each side, thus forming two segments, and giving a pinnatilid 
appearance to the filament. Filaments pale green, gelatinous, pro- 
bably not twisted. Transverse view linear or oblong. This genus 
differs from Besmidium, Bidymoprium, and Hyalotheca, in its flat 
filaments (not t^dsted), in the deep division of the joints into seg- 
ments, and especially in the presence of the minute gland-like 
processes at the junction of the joints. On account of its deeply 
constricted joints, this genus forms a connecting link between the 
preceding and the following genera. 

S. vertehratum = ( Odotdella (?) unindentata, Ehr.) — Joints as broad 
as long, deeply divided into two segments by a narrow notch on each 
side ; junction glands oblique, soHtary at the centre of each margin. 
It is furnished with a broad, colourless, and veiy delicate mucous 
Bheath. (P. 2. f. 107.) Length l-1429th. 

S. excavatum. — Joints longer than broad, having a deep sinus on 
each side, and two sessile glands on each margin at their jimction. 
Filament minute, fragile. The sporangium is formed between the 
conjugating joints, and is elliptical in figure. 

S. lamelliferum (Corda.) — Filaments short; nearly uniform; joints 
divided by a transverse line to one-third of their depth, segments 
rounded. 

^.pulchrum (Bailey.) — Joints twice as broad as long, deeply incised 
on each side ; junction-margins sti'aight, connected by short bands. 
It is twdce as large as S. vertehratum. 

^.filiforme = OdonteUa {}) JiUformis and Tessarthra filiformis (Ehr.) 
— Joints bilobed, xmited by double slender processes, which enclose 
a quadrate foramen between each pair. 

S. serratiim (Bailey.) — Joints broader than long, deeply notched or 
divided into two transverse portions, with acute projecting ends, 



244 BESCEiPTiON OF \Tolygastrica. 

which give a serrated outline to the chain. Common in fresh water 
in South Carolina, Georgia, and Florida. 

Genus Miceasxerias (Ag.) — Frond simple, (binate only when 
dividing), deeply divided into two, lobed segments ; the lobes incise 
dentate, (rarely only bidentate), and generally radiant. 

In two species sporangia have been detected ; they are large, glo- 
bular, and furnished with short spines, which at first are simple, but 
subsequently branched at the apex. In the perfect state they are 
particularly interesting from their resemblance to the fossil " X.an- 
thidia,^'' of Elirenberg and others. 

The orbicular, plane, and deeply incised fronds will distinguish 
Micrasterias from all other genera in this family. In Euastrum, the 
only one with which it can be compounded, the fr-onds are oblong, 
and the lobes are not incised. 

This genus is not equivalent to the one so named by Ehi'enberg. 
(See the genus Pediastrum.) 

* Frond circular ; segments five-lohed ; lobes a/pproximate, the end 
lobe narrow. 

M.. denticulata.=Euastriirn Rota, (Ehr.) — Large, orbicular, smooth; 
lobes cuneate, dichotomously divided, the ultimate sub-divisions 
truncate-emarginate with rounded angles ; the end lobe, the narrowest, 
is simply emarginate. (P. 2 f. 121, 122, 123, and Sporangium, 
P. 13, f. 22.) 

The process of conjugation appears similar to what takes place in 
Staurastrum dejectum ; the contents of both fr-onds unite, and form a 
globular sporangium enclosed in a fine membrane, and its snrface 
gradually acquires scattered, stout, elongated spines, at first simple, 
with their apex obtuse, but afterwards forked or trifid ; and, 
finally, further branched, and frequently more or less re-curved. The 
sporangia are of considerable siije, — a necessary consequence of the 
union of the contents of both fronds. (P. 13, f. 22.) 

The truncate ends of the sub-divisions distinguish this species 
from M. rotata. Length 1-1 13th. 

M. rotata. — Orbicular, smooth ; lobes dichotomously incised, ulti- 
mate sub-di\dsions bidentate. It differs fr'om M. denticidata, in 
having the ultimate self-divisions dentate. Length 1-9 1th. Breadth 
1- 104th. 



Desmidie^l iNFrsoRiAt ANiMAtrrtE?. 245 

Mtckastehtas fimhriata. — Orbicular, smooth ; lobes dichotomously 
incised, ultimate sub-divisions obtusely emarginate, spinoso-miicro- 
nate. Length 1 -108th. Breadth 1-1 19th. 

M. radwsa= Mmstrmn Sol. (Ehr.) — Orbicular, smooth; lobes 
dichotomously divided; ultimate sub- divisions inflated, attenuated 
at the end, bidentate or mucronate. Differs fi'om M. rotata in its 
inflated sub-divisions. Length 1-1 38th. Breadth 1 -138th. 

M. papillifera. — Orbicular, with marginal gland-like teeth ; 
segments five-lobed ; lobes dichotomously incised ; the principal 
sinuses bordered by a row of minute granules. Sporangia similar 
to those of M. denticidata, but smaller. Endochrome brownish green. 
Length l-221th. to l-20,5th. Breadth l-238th. to l-211th. 

* * Frond suhcllipfie ; segments three or five-loled ; lobes radiant, 
the end one someuhat exserted and divergent. 

M.fureata. — Segments five-lobed ; lobes bifid; their divisions linear, 
divergent, and forked at the apex. Frond smaller than that of M. 
rota fa ; its outline broadly elliptic, sometimes almost circular. En* 
dochrome green. Length 1-1 35th. Breadth 1-1 56th. Very rare. 

M. crux-melitensis = Euastrum crux-meliiends. (Ehr.) — Frond 
rotundato elliptic ; segments sub-five-lobed ; lobes bifid, sub-divisions 
short, stout and bidentate at the apex. Size same as M. fureata, 
and similarly di\'ided. Empty fronds very delicately punctated. 
Length 1 -200th. Breadth l-221th. Very rare. (P. 2. f. 124.) 

M. americana. = Euastrum. Americanum. (Ehr.) — Angular ellip- 
tic; segments thrce-lobed, end lobe with bipartite angles; lateral 
lobes broad, margin concave, inciso-serrate. (P. 13. f. 44.) 

Var. («.) — Serratui'es distinct. 

Var. {b.) — Scrratures obscui-e. Length 1 -204th. Breadth 1 -254th. 
Rare. 

*** Fronds orbicular ; segments obscurely five-lobed ; the end one 
broadest. 

M. truncata. = Exiastrum Rota. (Ehr.) — Orbicular, segments 
with five-shallow lobes, the end one very broad, truncated ; lateral 
ones inciso-dentate. Length 1 -240th. Breadth 1 -250th. 

M. erenata diftcrs from M. truncata in the convex margin of its 
end lobes, and the absence of teeth on the lateral ones. Length 
l-244th. Breadth l-263rd. 



246 DESCRIPTION OF [Polt/c/astrica. 

* * * * Fronds ohlony. 

MicEASTEKiAs Jemieri. — Oblong, minutely granulated; segments 
five-lobed ; lobes closely approximate, cuneate ; lateral ones obscurely 
bipartite, sub-divisions emarginate. Transverse view fusiform. {A.) 
granules appearing like mere puncta ; (5) granules larger, giving a 
dentate appearance to the margin. 

This species seems to unite Micrasterias with Euastrum. It 
agrees with the latter genus in figiu-e, but the lobes have incon- 
spicuous incisions, which divide them into two portions, each slightly 
emargiaate. A transverse view shews the absence of the protuber- 
ances always found ia true species oi Euastrum. Length 1-1 47th. 
Breadth l-209th. 

* * * * * Loles horizontal, attenuated, hidentate. 

M. oscitans. — Smooth, with convex ends ; segments constricted ; 
lobes horizontal, conical, bidentate. Transverse view fusiform. 
Length l-156th. Breadth l-211th. (P. 13, f. 28, 29.) 
>• M. pinnatifida. — Minute, plane, its ends straight ; segments deeply 
constricted ; lobes horizontal, triangular, bidentate ; resembles If. 
oscitans in foim, but its surface is flatter, the end margin straight 
or slightly concave instead of convex, and the lobes more tapering. 
Length 1 -440th. Breadth 1 -392nd. 

M. apiciilata = Euastrum apiculatum, (Ehr.) — Orbicular, rough, 
"with scattered spines ; segments five-lobed, lobes incised and toothed, 
and lobe narrow. 

M. quadragies-cuspidata. — Has scattered hair-like spines ; end lobe 
the broadest. 

"M.. foUacea (BaUey). — Sub-quadrate; end lobes nan-ow, with 
emargiaate angles ; lateral lobes inciso - dentate, with a short, 
rounded tooth-like projection next the end lobe. 

M. Torreyi. (Bailey.) — Orbicular ; lateral lobes deeply incised ; 
inner sub-divisions acute ; external, bidentate at the apex ; all taper- 
ing. End lobe nan-ow and not exserted. 

M. muricata- — Segments divided by deep indentations into three 
transverse portions ; the basal with three, the others with two linear 
processes on each side. 

M. muricata differs remarkably from 31. furcata and eveiy other 
known species. The division into five lobes is indicated merely 



Desmidieiv ] iNFUsoRrAL animalcules. 217 

by the presence of processes, which, unlike those in the other species, 
do not diverge in the front view, but spread laterally, in such a manner, 
that the one nearest the eye, more or less conceals its companions. 

MicRASTEEiAS BaUeyi. — Granulated ; segment three-lobed ; lobes 
bipartite, end one much exserted ; all the sub-divisions bidentate at 
the apex. 

M. incisa = Euastrum crux-melitennis, (Ehr.) — Lobes horizontal, 
basal ones tinmcate, with a tooth at each angle ; end lobe convex, its 
angles acute. 

The following new species are foimd in the Southern States of 
America, and were discovered by Dr. Bailey of New York in 1850. 

M. arcuata, (B.) — Quadrangidar segments three-lobed, the basal 
lobes long and arcuate, subtended by the transverse projections 
from the ends of the slightly notched terminal lobes. An interesting 
and very distinct species, which can be confounded with no other 
except the following. Lakes in Florida. 

M. expansa, (B.) — Segments three-lobed, basal lobes long, sub- 
conical, acute ; terminal lobes slender, forked at the end, with the 
divisions much shorter than the basal lobes. This somewhat re- 
sembles the preceding species with which it occurs, but I have seen 
no intermediate forms, out of many hundreds of each, and the cha- 
racters above given appear sufficient to separate them. 

M. quadrata, (B.) — Large, quadrangular, 3-lobed, basal lobes 
elongated, slightly cmwed, bidentate ; terminal lobes with two slender 
transverse bidentate projections. Its larger size, and distinctly 
bidentate projections, sufficiently distingmsh it from the two preceding 
species. 

M. ringens, (B.) — Oblong, segments three-lobed, coarsely granulated 
near the edge ; basal lobes sub-divided by a deep notch into two, 
rather broad and obtuse, or slightly bidentate projections ; terminal 
lobes exserted, emarginate; extremities bidentate or obtuse. Re- 
sembles M. Baileyi, but is larger, divisions less slender, and with the 
granulations differently placed. 

Genus Euastrum. — Frond simple, compressed, deeply divided into 
two segments which are emarginate at their ends, lobed or sinuated, 
generally pyramidal and ftimished with circular inflations. 

In Euastrum, Ehrenberg includes Micrasteaias (Agardli.) not 
Micrasterias, (Ehr.) and Cosmariwn ; Euastrum agrees with Mtcras- 



248 DESCRIPTION OF [Poli/ffastnca. 

terias in having lobes and cmarginate ends, but the lobes are not 
incised, nor do thoy radiate from the centre, and the inflated projec- 
tions will distinguish it not only from Micrasterias, but from every 
other genus in the family. From Cosmarium it differs also in the 
lobed and emarginate segments. 

Ehrenberg's characters of this genus Euastrum, or star-dislced Ani- 
malcules are — members free, inclosed in a simple compressed lorica, 
composed of only one piece, and by their adhering in pairs, which 
are disposed in the form of a two-lobed disc or table. Whether a 
lobe can be regarded, separately from its companion, as a distinct 
organism, is not determined, but by cutting or destroying the 
one, the other empties itself at the same time, although the lorica 
appears detached in the middle. No openings have been seen in the 
ends, as in Micrasterias, but it is probable such exist in the middle, 
where they are connected. The lorica is membranous, firm, colour- 
less, and combustible ; it contains the hyaline and contractile 
body of the animalcule, filled with green granules. Its propa- 
gation by self-division is jjeculiar and highly interesting. (See 
f. 123.) The middle elongates, and fi'om it two new segments are 
formed, one uniting and forming the companion to one of the old 
ones, and the other producing the same with the remaining old 
one, when the newly-formed individuals separate, and two pairs 
are the result. From this method of self-division, specimens having 
unequal lobes, are produced by any accidental rupture, before 
the new ones in the middle are fully developed. All the species are 
found among conferva. 

Mr. Ralfs divides this genus into three sections. 
1 . Segments of the frond deeiily hied ; terminal lole cuneate, and partly 
included in a notch for med by the projection of the lateral lobes. 
EuASTRUJi verrucosum (Ehr.) — Frond rough with conic granules; 
segments three-lobed ; lobes broadly cuneate with a broad shallow 
notch. Transverse view oblong, with three inflations at each side, 
and a smaller one at each end. It is known by the conic granules 
giving a dentate appearance to the outline. Length 1 -267th. 
Breadth 1 -270th. (P. 2. f. 125.) 

U. oblongum = (E. pecten, Ehr.) — Smooth, oblong ; segments five- 
lobod ; lobes cuneate, emarginate, the terminal one partly included 
between the lateral ones. Empty fronds pimctate. Sporangia orbi- 



Ihsinidiea.'} infusorial akimalcules. 249 

ciilnv, with numerous conic tubercles. Length l-156th. Breadth 
l-282ncl. Transverse view three times longer than broad, with 
three rather distant inflations or lobes on each side, and one at each 
end. 

Euastkitm: crassum. — Smooth; segments three-lobed, subquadri- 
lateral ; terminal lobe cuneate, partly included in a notch formed by 
the lateral lobes. Transverse view with tlu'ee lobes on each side, 
and one at each end. Empty frond pimctate. 

Var. (5.) — Smaller, sides more concave; base more inflated ; and 
the angles including the terminal lobe more elongated. Length 
l-193rd to l-132nd. Breadth l-263rd. to l-260th. 

2. Segments sinuated ; terminal lobe exserted, and united with the basal 
portion by a distinct nccJc. 

E. pinnatum. — Five lobed; end lobe exserted, dilated; upper 
margin, of lobes horizontal. Basal lobes emarginate; the inter- 
mediate ones smaller and entire. Empty frond punctate. Length 
l-888th. Greatest breadth at basal lobes l-454th. 

E. humerosum. — Smooth, terminal lobes dilated ; emarginate; neck 
partly included between the elongated middle lobes, which resemble 
processes ; basal lobes emarginate. Empty frond minutely dotted. 
Transverse view has three lobes on each side, and one at each end ; 
whence it differs from E. affine. It is distinguished from all other 
species in this section by its included neck. Length 1 -225th. Breadth 
l-382rd. 

E. affine. — Three-lobed, with intermediate tubercles ; lobes emargi- 
nate, end one dilated, its notch linear. Transverse view with four 
lobes on each side. Empty frond punctate. 

E. ampullaceum is best recognized by its short segments, in which, 
and its broad inflated base, it diftcrs from E. affine ; whilst the dis- 
tinctly dilated terminal lobe separates it from E. didelta. Empty 
frond punctate. Length 1-2 74th. 

E. insigne. — End view cruciform. Empty frond pimctate. The 
transverse view differs from that of every other species in being con- 
tracted at the middle. The inflated base and slender neck, conjoined 
with its dilated end, are suflSciently characteristic. Length 1 -232nd. 

E. didelta. — Segments with inflated base, intermediate tubercles, 
and notched, and scarcely dilated end ; transverse view, four shallow 
lobes on each side, and one at each end. Segments pyramidal; 

B 



250 DESCRIPTION OF {^Polygastrica. 

neck broad. End \'icw bilobed. Empty frond punctate. Sporangia 
orbicular, with subulate spines. Length 1-1 85th. 

ExJASTKTJM ansatum (Ehr.) — Segments inflated at the base, and 
tapering upwards to the notched but not dilated extremity ; trans- 
verse view cruciform. The end view has two circular and entire 
lobes. Empty frond punctate. Length l-315th. 

E. circulare. — Segments three-lobed, mostly with five basal 
tubercles ; four of them usually disposed semi-cu'cularly about the 
fifth; end notched, scarcely dilated. Length 1- 320th. 

E. pectinatum. — Segments three-lobed; terminal lobe dilated, 
scarcely emarginate ; lateral lobes emarginate, horizontal ; end view 
two-lobed at each end, and two lobules on each side. Neck short 
and broad. (P. 13. f. 10.) Empty frond pimctate. It differs 
from aU the preceding, m the absence of a terminal notch, in the 
lobules of the end lobe, and in having the ends emarginate in the 
transverse view. Sporangia orbicular mth conical tubercles, or 
short obtuse spines. (P. 13. f. 30.) Length l-362nd. Boggy pools. 

E. gemmatum may be known from all in this section, except E. 
pectinatum, by the absence of a linear terminal notch ; and from that 
species by the smallness of the end lobe, and the outward direction of 
its angles, and by the miuute granulation of the projecting parts. 
Length 1 -442nd. 

3. Frond without a distinct terminal lohe, and frequently having a 
processor an acute angle at the corners of the terminal portion. 

E. rostratum, minute, oblong; ends protuberant, emarginate, and 
angular, with a horizontal spiue on each side ; neck, attaching the 
terminal lobe of each segment, short and broad. The angular and 
less prominent ends distinguish it from E. elegans. Sporangia 
spinous. Length 1 -649th to 1 -508th. 

E. elegans, very miuute, oblong ; ends emarginate, pouting and 
rounded. 

Var. fa. J — Segments slightly constricted beneath the end lobe, 
which has on each side a short horizontal spine. 

Var. fhj itierme ; segments sinuatcd rather than lobed, and without 
spines. 

Var. fc.J — Segments as in fh), but with two or more spines, 
directed obliquely outwards. Length l-421st to l-884th. 

E. hinale. — Segments concave, or truncate at the end ; not pro- 



T)psmulie(P.'] iNPusoniAL animat.cfles. 251 

jccting beyond the acute angles. Frond verj- minute. Terminal 
notch broad. 

Var. /^i.y— Quadilatcral form ; truncate ends, with a small but 
distinct notch at the centi-e. Length l-1968th to 1-1 106th. 

EtTASTRTm cuneatum. — Segments cuneate, not lobed ; terminal notch 
not lineal'. Frond larger than that of any other species in tliis 
section. Ends truncate. Length 1-20 8th. 

E. (?) sublobatum. — Segments sub-quadrate, somewhat conti'acted 
beneath the end ; end margin sKghtly concave. Sides and end of 
segments somewhat siuuated, and their base slightly inflated. This 
species has close affinities with Cosmarium. Length 1 -523rd. 

E. cormitum (Kiitz.) — Segments three-lobed; terminal lobe cuneate, 
included between two process-like projections of the basal portion. 

'E. pelta. (Corda.) — Segments quadrangular; end margin with a 
rounded protuberance at each comer ; lateral margins with a small 
protuberance at the basal end, and a larger one nearer the outer end. 

E. crenatum. (Kiitz.) maybe a variety of ^. elegans. 

E. crenulatum (Ehr.) — Small, corpuscles binate, elliptic, granular; 
mai'gin with 8 to 12 crenatures. Size 1-1 150th. 

E. hinale (Ehr.) = Hetorocarpella hinalis (Turpin.) — Corpuscles 
binate, sub-orbicular, distinctly tri-lobed on each side ; each of the 
terminal lobes truncate ; the middle contiguous lobes rounded. 
Diameter 1 -480th. Under the above name, both Ealfs and Ehren- 
berg have described the Heterocarpella hinalis of Tui'pin ; yet the 
descriptions would scarcely identify the same species, and the dif- 
ference in size, as stated by the two natui-alists, is very considerable. 
Ehrenberg's description is from a paper published in 1840. 

E. octohhim (Ehr.) — Corpuscles binate ; fi-ond oblong, plane, four 
lobed on each side, the intermediate contiguous lobes bidentate at 
the apex. Diameter 1-5 70th. 

E. (?) j3y^/rt«M?w = Frustulia cofecdformis. — Binate, very small, 
elliptic, smooth, quite entire, imbedded in a gelatinous substance 
with other specimens (social.) Diameter 1-1 750th. Maiine. 

Genus CosMARnrM:. — Corpuscles simple, constricted in the middle ; 
segments as broad as, or broader than long ; neither sinuated nor 
notched ; mostly Lnflato-compressed, but in some species orbicular, or 
cylindrical. Ehrenberg united plants belonging to this genus with 
others having lobed segments, in order to form his genus Euastrum 

s 2 



252 DESCEiPTioN OF [Poli/gastrica. 

Those species having cylmch-ical fronds, show an affinity with 
Penium ; but in that genus the constriction is either wanting or 
obscui'e, and the segments are longer than broad. Cosmarium is 
always constricted in the middle, and the starch vesicles are scat- 
tered. Tetmemorus differs in its elongated fronds and emarginate 
extremities. 

1 . Frond comjjressed, deeply constricted at the middle ; end view ellipti- 
cal. — Margin of segments entire. 

CosMAJRiUM quad/ratum. — Minute, smooth, deeply constricted ; seg- 
ments in front view quadrate, and on each side of the base slightly 
protuberant ; its ends less rounded than in C. cucumis. 

C. Cucumis = Euastrum integerrimum, Ehr. (?) — Smooth, deeply 
constricted ; segments as broad as long, rounded at the ends ; trans- 
verse view broadly elliptic ; smaller than C. JRalfsii, less orbicular, 
and transverse view different. 

CosMAiiiXTM Ralfsii. — Large, orbicidar, smooth ; deeply constricted ; 
transverse view fusiform. Differs from C. Cucumis by its larger size 
and disciform appearance. Length 1 -225th. 

C. pyramidatum. — Oval, with flattened ends, deeply constricted ; 
seg-ments punctate, entire. Frond about twice as long as broad, 
varying much in size. Sporangia orbicular, and tuberculated. Dis- 
tinguished by its puncta and depressed ends. 

C. tinctum. — Yery minute, smooth; constriction producing a 
linear notch on each side ; segments elliptic ; integument reddish ; 
sporangium naked, subquadrate, conjugating ft-onds persistent. Smaller 
than C. hioculatum , and its notches less gaping. 

C. hioculatum. — Very small ; smootli ; constriction producing a 
gaping notch on each side ; segments sub-elliptic, entii-e ; sporangium 
orbicular, spinous. Differs from C. pliai^eolus in its smaller size, and 
more elliptic segments, "svhich are not in apposition. 

C. deperessum (Bailey.) — Elliptical, binate, division in the plane of 
the longest axis. Segments entire, nearly twice as long as broad. 
Lakes in Florida. This species resembles C. hioculatum, (Brobisson.) 
But the segments arc much closer together, and are angular, not 
rounded at the basal extremities. 

C. granatum. — Constriction of fr-ond forming a linear notch on 
each side ; segments compressed, smooth, truncato-triangular. Larger 
than C. hioculatum and C. Meneghinii. Length 1-123 1th. 



Desmidiece.] INFUSOEIAL animalcules. 253 

Iff Margin of segments crenate ; surface not granulate. 

CosiTAiauir Jleneghinii. — Exceedingly minute ; smootli, deeply con- 
stricted ; segments sub-quadrate; sides and ends bier enate. Transverse 
view elliptic. (l-853rd.) 

G. crenatmi. — Punctate, deeply constricted; segments crenate, 
and flattened ; spines of orbicular sporangia very short. Smaller 
than C. margaritiferum ; end view elliptic. The depressed ends 
distinguish this species from the next. (l-474th.) 

C. unduhtum. — Deeply consti'icted ; segments semi-orbicidar, cre- 
nate; sporangia Avith elongated spines. Transverse view elliptic. 
(P. 13. f. 33. 34.) f. 34 shows the sporangium. 

t f t Frond ivith pearly granules, ivhich give a denticulate appearance 
to the margin. 

C. tetraophthalmum. — Compressed, deeply constricted ; segments 
semi-orbicidar, rough with pearly granules ; hence margin crenate. 
Lai'ger than C. margaritiferum. Transverse \-iew broadly elliptic. 
Spoi'angia large, -\Aith branched spines. 

C. ovale. = Euastrum carinatum (Ehr.) — Large elliptic ; deeply 
notched, linear; segments with a marginal band of pearly granules; 
disc punctate. Granules confined to the margin, in 3 to 6 rows, 
leaving the disc free. Length 1-1 39th. 

C. Botrytis. = Euastrum lofrytis and E. angulosuni (Ehr.) — Gra- 
nulate ; with a deep linear constiiction ; segments in fi'ont view, trun- 
cato-triangidar ; end view elliptic. Margin denticulate. Sporangia 
orbicular, spines elongated, and slightly divided at the apex. 
(l-460th.) 

C. margaritiferum. = Euastrum margo/ritiferum (Ehr.) — Rough, 
with rounded pearly granules ; segments semi-orbicidar, or reni- 
form ; end view elliptic ; notch linear. Sporangia orbicular, enclosed 
in a granulate cell, usually somewhat angular. 

The rough fi'ond distinguishes it from C. crenatum and C. undu- 
latum ; its rounded ends from C. botrytis, and its less angular shape 
from C. conspersum. Size variable. (P. 2. f. 126.) 

C. Brehissonii. — Compressed, rough with conic spines, or granules ; 
segments semi-orbicular ; end view elliptic. Larger than C. marga- 
ritiferum ; notch deep, Unear ; gi'anules or spines longer than broad. 
(1 -285th.) 



254" DESCBiPTiON OF {Polygostrica. 

CosMAEnnir conspersmn. — Rougli with depressed granules ; segments 
quadrilateral ; end view elliptical, larger than C. margaritiferum : 
notch on each side linear deep. Is peculiar in its quadrilateral 
figure, and linear disposition of its granules. (1 -260th.) 

C. amcenum. — Twice as long as broad, with parallel sides and 
rounded ends ; rough, with pearly granules ; smaller than C. marga- 
ritiferum ; notch linear and deep. In form, it resembles the cylin- 
drical rather than the compressed species. (l-560th.) 

2. Constriction, in the front view, forming a linear notch on each 
side ; end view with a lohe or protuherance wt each side. 
f Frond rough, xvitli pearly granules. 

C. hiretum. — Segments compressed, quadiilateral, broadest at the 
end; end margin convex. Frond larger than that of any other 
species in this section. The empty frond punctate rather than gra- 
nulate. End view slightly inflated at the middle. From all except 
C. Broomeii, this species is known by its quadrangular segments, the 
lateral margins of which are sloped and straight, not rounded. 
(l-330th.) 

C. Broomeii. — Segments compressed, minutely granxilate, quadri- 
lateral ; end view slightly inflated at the middle ; end margin 
straight. The inflation does not project at the margin in the front 
view as in C. ornatum ; the lateral margins are also less rounded, 
and the pearly granules smaller (l-500th.) 

C. ccelatwm. — Suborbicular ; segments crenate, rough with pearly 
granules; end view slightly inflated at the middle. (P. 13, f, 26 — 
shewing the process of self-division.) 

C. ornatum. — Segments twice as long as broad, rough with pearly 
granules, giving a dentate appearance to the margin ; inflation form- 
ing a truncate projection at the end ; end view cruciform. The frond 
is generally smaller than that of C. margaritiferum; notch linear. 
Sporangia spinous; spines elongated, slightly divided at the ex- 
tremity, and dilated at the base. 

C. commissurale. — Segments narrow, reniform, three times broader 
tlian long ; rough with pearly granules ; end view with a constriction 
between the central inflation and the extremities. Smaller than 
that of any other species in this section. Sporangia orbicular; 
spinous. 



Desmidiea.'} infusorial animalcules. 255 

CosMARiUM cristatiim. — Orbicular, deeply constricted, margined by 
papilla- like pearly granules ; end \'iew linear, ^yitb an inflation at 
tlie middle of each side. (1 -700th.) 

t f Frond Smooth. 

C. Plmscolus. — Segments smooth, reniform ; notch linear on each 
side; end view elliptic, Avith a slight projection at the middle of each 
side. Larger than C. hioculatum ; and its segments are reniform, 
and the notches linear, not gaping. (1 -687th.) 

C. Fapilio. — Segments smooth, ti-iangular, with rectangular apex ; 
end view linear with a lobe at the middle of each side. This species, 
named by Meneghini, is appended by Mr. Ralfs to those known to 
liimsclf, and appears to fall under this sub-section. 

3. Constriction not forming linear notches at the sides; end view 
circular. 

t Frond rough with pearly grunules, which give a denticulate a/ppea/r- 
ance to the outline. 

C. cylindricum. — Segments granidated, sub-quadrate in front view ; 
broadest at the extremity ; minute, cylindrical, about twice as long 
as broad. (l-588th.) 

C. orhiculatum. — Minute ; segments spherical, granules wanting on 
the neck-like contraction between the segments. Transverse view 
has a large central opening. 

1 1 Frond smooth. 

C. moniliforme = Tessarthra moniliformis, (Ehr.) — Segments sphe- 
rical, smooth. 

Var. fa. J — Segments united without the intervention of a neck. 

Var. fb.J — Segments united by a distinct neck. (P. 2, figs. 105, 
106.) 

C. connatum. — Segments punctate, each about two-thii-ds of a 
circle, uniting by their plane surfaces ; fronds slightly constricted at 
the middle. Very large (l-285th.) 

C. Cucurlita (?) = C. Palangula, (Breb.) — Minute, sub-cylindrical ; 
punctate, slightly constricted; rounded at the ends. (l-586th.) 

C. Thwaitesii. — Cylindrical ; constricted ; ends rounded ; puncta 
very indistinct, two or three times longer than broad. It diifers 
from (7, Cucurlita in its larger size and indistinct puncta ; from C. 



256 DESCEiPTiON OF [Poli/ffastrica ^ 

curtum, in its differently arranged endochrome ; and from t'. turgidum 
and C. attenuatiim, in its nearly parallel sides. (l-357th.) 

CosMAnruM curtum. — Minute, smooth; oblong; constricted; rounded 
at the ends ; cndochrome in longitudinal fillets. End view circular. 
(l-465th.) 

C. attemiafum. — Fusiform, three or four times longer than broad ; 
slightly constiicted ; ends obtuse. It is doubtful, says Mr. Ralfs, 
"whether this and C. turgidum ought not to be removed to Pe)iium. 

C. turgidum, — ^Large, turgid, oblong, punctate, constricted ends 
broadly rounded. It differs from the allied species in its much larger 
size. It is comparatively longer and more tapering than C cucurhita 
and C Thicaitesii, and its ends are more rounded than those of C. 
attmuatum. Length l-126th. 

C. lagenarimn, (Corda). — Segments triangular; all the angles 
broadly rounded. 

C- ventricoswn (Kiitz.) — Mr. Ralfs says, "I believe this to be a 
species of Cosmarium in a dividing state." 

Genus XANTHiniFM, (Ehr.) — Simple, constricted in the middle ; 
segments comj)ressed, entu-e, spinous, having a circular projection 
near the centre, which is usually tuberculated. Segments reniform, 
orbiculai-, or angular ; sj)ines scattered or arranged in two rows, one 
on each side of the marginal line. 

The resemblance of Xanthidium^ and Staurastrmn is more apparent 
than real, the cells of the latter are angular, UTespective of the pro- 
cesses. In Arthrodesmus, each segment has only two spines, one on 
each side, and there are no central projections. The connection with 
Cosmarium is far more intimate ; in fact, the sole distinctive character 
that can be relied iipon, is the presence of spines in this genus. 

Several plants referred by Ehrenberg to Xanthidium, are angular 
in the end view, and properly belong to Staurastrmn, thus : X hir- 
iutum = Staurastrmn hirsutum, (EaLfs.) 

Agassiz believes the Xanthidia, generally to be the sporangia of 
Algce; but he adduces but one instance in favour of this notion, 
■where he observed Xanthidia, growing as Sporangia, uj)on the 
branches of an Alga), surrounded with mucus. 

Ehrenberg' s chaxactcrs of the genus Xanthidium or double-bur 



Desmidiece.l infusorial ANiMALcuLEg. 257 

Animalcules, are theii' "being free (devoid of pedicle or stalk) and 
haviBg a simple univalvcd lorica, of a globidar form, surrounded with 
spines. They are found either single, in pairs, or groups of four. 
Ehrcnbcrg thinks they may sometimes be developed in the form of a 
chain. The lorica is cleai', like glass or parchment, covered with 
simple or branched bristle-like spines. No apertures have been dis- 
covered in the lorica, nor has any locomotive ox'gan been seen. The 
green mass of granules in the interior is considered as ova, and the 
glandular transparent globule observed in the centre of X aculeatum 
as a testes. The only character of the animal nature of this genus 
is its self-division" 

All the species (as understood by Ehrenberg, see p. 260), have 
been found in a fossil state in flints. In some sections, which I cut 
in 1834, they were very abundant, but until Elirenberg's obser- 
vations on them were known, they were not identified with recent 
species, and then considered as mere defects in the stone. 

XAKTHinruM diffonm, (Ehr.) := Ankistrodesmus falcatus, (Ralfs.) 
Mr. Kalfs has arranged this genus as follows: — 
* Spines divided at the apex. 

X. armatum. — Segments broadest at the base ; spines short, stout, 
terminated by three or more diverging points. Comparatively large ; 
a deep linear constriction on each side. The central protuberances 
are cylindrical, truncate, and bordered by pearly granules. Empty 
frond minutely pimctate. End view elliptic. Length 1 -180th. Not 
uncommon at the bottom of shallow pools. 
*■ Spines subulate. 

X. aculeatum (Ehi-.) — Spines subulate, more or less scattered, 
centi-al projections trimcate, obscurely dentate, with a border of 
pearly granules. (Fig. 109.) This species is distinguished from all 
the following, by having its spines more or less scattered. Length 
l-384th to l-377th. Breadth l-393rd to l-347th. 

X. Brebissonii = X. bisenarium (Ehr.) — Spines subulate, marginal, 
geminate ; central projection somewhat truncate, and margined with 
pearly granules. 

Var. {b) varians. — Segments broader and more irregular; spines 
somewhat irregular and unequal. The number of spines is variable 
Length l-4I6th. Breadth l-408th. 



258 DESCRIPTION OF \JPolygastrica. 

XAJfTHiDrtTM fascicidatum (Ehr.) — Segments with foiir to six pairs of 
subulate marginal spines; central projections minute, conical, not 
beaded. 

Var. {a.) — Each segment with four pairs of spines. 

Var. (J.) — Six pairs of spiues to each segment. Length 1 -454th. 
to l-350th. 

X. cristatmn. — Segments with a solitary spine on each side at the 
base; the other spiaes gemiuate, (P. 13. f. 18 and 23, the latter an 
end view.) 

Var. {a.) — Segments reniform ; spines scarcely curved. 

Var. {I.) — Segments truncate at the end; spiaes uncinate. Length 
l-357th. 

X. (?) octocorne (Ehr.) also = Arthrodesnms octocornis (Ehr.) — Seg- 
ments much compressed, without a central protuberance, trapezoid ; 
each angle terminated by one or two spines. Erond minute ; iuterval 
between the angles concave. 

Var. {a.) — One spine at each angle. 

Var. (1.) major. — Larger, two or more spines at each angle. 

The proper position (says Mr. Kalfs) of this plant, wantiug, as it 
does, the central protuberance, is very doubtful. Ehrenberg placed 
it first in Arthrodesynus, and afterwards in Xanthidium. Length 
l-1351stto l-1020th. Common. 

X. Artiscon (Ehr.) — Segments naiTowed at the base ; and margin 
with numerous elongated spiaes, which arc divided at the apex into 
three lobes. Figured by Dr. Bailey. 

It differs from X. armatum by its segments tapering at the base ; 
its spines also are much longer and are more restricted to the outer 
and rounded margin. Diameter 1-11 52nd to 1 -288th. 

'K. fHrcatum (Ehr.) — Corpuscles globose, green, single or binate, 
spinous; spines scattered, forked at the apex. Size 1-5 70th to 
l-280th (fig. 110.) 

This is probably a Staurasfrum. According to Ehrenberg the 
corpuscles sometimes occur in fours ; also some have but one spine, 
and some short and broad processes. The spines are usually half the 
length of the body. 

Under the name Xanthidium, Ehrenberg described various bodies, 
more or less branched and orbicular (P. 12. f. 511 to 515) found in 



DesmidiecB-l iNFrsoRiAL animalcules. 259 

sections of flints, and also fossil occasionally in earth. The reference 
of these fossil organic remains to this genus is not supported by any 
acciu-ate examination, and not even by outward characters ; their 
general characters are as those of spores of DesmidiecB and of other 
microscopic Algae. 

The number of these so-called fossil Xanthidia has been much 
added to by other observers; we append those given by Ehi'enberg. 
XANTHiDitrir (?) ramosum. — Lorica globose, spinous; spines trifid or 
branched at their extremities ; they vary in number from 6 to 20, and 
singly or in pau's (P. 12. f. 511 and 515.) Found in flint. Most 
probably sporangia. Ekrenberg thinks its true place is the genus 
Peridinium, as traces of a transverse groove have been observed. 
Diameter 1-11 50th to 1 -280th. 

X. crassipes. — Lorica globose ; large. There are two varieties ; in 
one the thick blunt spines appear distinct, in the other they appear 
as a fringe around the lorica. Found in flint. Diameter l-280th. 
X. penicillatiim. — Fossil in earth from the Jura. 
X. pilosum. — Fossil in earth from the Jura. 

X. (?) tuliferum. — Corpuscles globose, single and in pairs, aculeate ; 
spines in the form of tubes, dilated and dentate at the apex. Diameter 
l-400th. 

X. hulbosum. — Corpuscles globose, single or binate, aculeate ; 
aculei attenuate, forked at the apex, bulbous at the base. Diameter 
l-400th. 

Genus Aktheodesitcts. — Frond simple, compressed, constricted at 
the middle ; segments smooth, entire, with a single spine on each 
side. The sporangia spinous. Mr. Ralfs says : — " Where the plants 
should be placed, to the reception of which I have restricted this 
genus, has been left in much imcertainty. Ehrenberg, making no 
distinction between constiicted and binate cells, has associated them 
with others belonging to Scenedesmus, to form his Arthrodesmus. Mr 
Jenner considers them to belong to Stmirastnim; and he beKeves he 
has met with one species, some specimens of which were compressed, 
whilst others had three angles in an end view ; whilst it must be 
further allowed, that in the front view the resemblance to some 
species of Stcmrastrum is veiy close. 

Although Mr. Ealfs has employed the name Arthrodesmus to 



260 DESCEiPTioii OF \^Polygastrica. 

designate the present genus, it does not represent the beings which 
Ehrenberg so named. The A. conrergens, (Ehrcnberg), is the only- 
one retained in the genns by Mr. Ealfs; the A. truncatus (Ehi-.) is 
quoted as doubtful, and all the other members are variously distiibuted, 
one with Xanthidium, and others in Scenedesmus. 

Ehrenberg's characters of his genus Arthrodesmus, are animalcules, 
free (no pedicle being present) ; they have a simple univalved com- 
pressed lorica, and multiply by spontaneous seK-division, in the 
form of tables, or compressed and articulated ribbons, each animalcule 
being contiguous to its neighbour. Neither locomotion nor an opening 
to the lorica has been seen. The chief animal character is self-division, 
and their close alliance, through Micrasterias and Euastrum, to Navi- 
cula, rather than to any known plant. The internal green colouring 
matter of their parchment-like lorica consists of minute homogeneous 
gi'anules resembling ova ; each cell-like lorica containing from one to 
tliree bright bodies, analogous to fecundating glands, which are often 
accompanied with crystalline vesicles, like polygasti-ic stomachs. 

Aktheodesmus co«fe/yms, (Ehi\) — Segments elliptic; each having 
its spines curved towards those of the other. Erond smooth, deeply 
constricted at the middle ; the transversely ellijitic segments (cor- 
puscles, Ehr.) have on each side a curved spine which converges 
with the similar one of the other segment. The frond has a gela- 
tinous covering, sometimes distinctly seen, at other times impercep- 
tible. (P. 2, f. 112, 113.) A. comer gens difl'ers from A. Incus, by 
its larger size and elliptic segments. Length of ft-ond l-598th to 
l-539th. 

A. Incus. — Minute, smooth ; end margin truncate. 

Var. fa. J — Segments externally lunate ; spines diverging. 

Yar. fh.J — Segments gibbous on each side near the base ; spines 
of one segment parallel to, or converging with those of the other. 
Sporangia orbicular with subulate spines. 

A. minutus, (Kiitz.) — Erond minute ; spines diverging. 

A (?) truncatus, (Ehr.) — Corpuscles gi'een, slightly compressed, 
campanulate, geminate, externally truncate, spinous. Diameter 
with spines 1 -480th. It is probably a Xanthidium or a Siatcrastrum. 

The two following forms have been referred, by Ehrenberg, to 
Arthrodesnms, and though in this genus, as understood hj Mr. Ralfs, 



DesmidiecB.'] infusorial animalcules. 261 

they can have no place, the descriptions given are totally insufficient 
to discover theii- true generic affinity, and we arc consequently com- 
pelled, for facility of reference to Ehrenberg's descriptions, to intro- 
duce them in the present inappropriate place, or otherwise to insert 
them in an appendix. 

AnTHEODESMUS Tceuia. — "Wands narrow, ilexihle, nearly eight 
times longer than broad, and smooth. Has the habit of A. striatulus, 
but is more slender. 

A. striatulm fFragilaria striatulus, Lyngbye.y — Met with in long, 
soft, green, but not siliceous chains, resembling Fragilaria rhabdosoma. 
Width of chain 1-5 76th. 

Genus Staukasteum. — Frond simple ; constiicted at the middle ; 
end view angular, or circular with a lobato-radiate margin, or, rarely, 
compressed with a process at each extremity. Frond mostly minute; 
the segments generally broader than long, slightly twisted, and in 
many species elongated laterally into a process, so that the con- 
striction on each side is a roundish or angular sinus ; in other 
respects the front view shows the segments quite entire, The end 
view varies in form : in most of the species it is triangular or 
quadrangular, and the angles are either rounded or elongated into 
rays ; in some it is circidar, with five or more processes, forming 
marginal rays ; in a few species it is compressed, and the extremities 
tei-minate by a process. 

" Ehrenberg has distributed the Staurastra among different genera, 
according to the number of angles or processes seen in an end view. 
Thus he refers those with three angles to Besmidium, and those with 
foiu" to Staurastrum ; and he formed his genus Pentasterias for the 
reception of an organism with five rays. But this arrangement 
appears unnatural; not only because it separates nearly allied forms, 
but also because the number of rays is not constant even in the 
same species. I have generally found the Pentasterias ma/rgaritacea 
(Ehr.) with six rays, although not unfrequently with five, and occa- 
sionally with seven rays to a segment. Staurastrum contains more 
species than any other genus hi the family : their forms are in great 
variety, and but little affinity can be traced between many of them. 
Sjmrangia generally spinous. Staurastrum differs from Besmidium 
in never forming a filament; and from Arthrodesmus and Cosmarium, 
by its angular shape, or by having the ends elongated into processes. 



262 DESCRIPTION OF [Polygastrica. 

Some species bear a considerable resemblance to species of Xan- 
thidium, to which genus Ehi'enbcrg refers them; but in Xanthidium 
the frond, iiTespective of the spines, is not angular in the end view, 
and there is a projection at the centre of each segment in the front 
view." 

Ehrenberg's characters of his genus Staurastrum or the cross-star 
Animalcules, are their being free, and possessing a simple univalved 
foiu-'sided lorica. They are sometimes, perhaps, developed in a 
filiform chain. No locomotion has been observed ; indeed their only 
resemblance to an animal, even as stated by Ehrenberg, is their in- 
crease by self-division, though he thinks the green matter within 
them ova. 

(A.) Frond smooth, or rough ivith mimde puncta-lilce granules ; end 
riew with the lobes or angles inflated and mucronated or awned. 

f Frond smooth. 

STAtrRASTRTTM: dcjectum. — Segments lunate or elliptic ; constricted 
portion very short ; end view with inflated awned lobes. 

Var. fa. J — Segments externally lunate ; awns directed outwai'ds. 

Var. fh.j — Segments elliptic ; awns parallel. 

Yar. fc.) — Awns converging. 

The conjugated fronds are connected by the formation of a bag-like 
receptacle or cell, colourless and very thin ; into this sac the endo- 
chrome of the two fronds passes, forms an orbicular body which 
increases in density, becomes hairy and ultimately spinous, and con- 
stitutes a perfect sporangium. S. dejectmn is larger than S. ciispida- 
tum, its spines are shorter, and its segments are connected either 
without a band, or by a very short one. Length of frond 1 -833rd. 

S. cuspidatum. — Segments fusifonn, connected by a long narrow 
band ; awns parallel or converging, but straight ; end view with 
3 to 4 inflated awned lobes. Length 1 -883rd. Sporangia with fewer 
spines than those of S. dejectum. 

S. aristiferum. — Lobes in front view prolonged into mammiUate 
awned projections which are somewhat constricted at the base ; end 
view with 3 to 4 awned lobes. (1-65 7th.) 

S. Diekiei. — Differs from the three preceding species in its more 
turgid sub-elHptic segments, and in the short, ciu'vcd, converging spines. 
End view with three slight inflated mucronate lobes. (1 -855th.) 

S. hrevisjnna. — Segments turgid, elliptic, minutely mucronate; 



DesmidiecB.~\ iNFrsoRTAL AXTMALcrLES. 263 

end view tliree-lobed, each lobe terminated by a short miicro. Larger 
than S. dejectum. Length 1 -502nd. 

f f Frond rough, with minute granules. 

STArrRASTKinu lunatum. — Granides puncta-likc, segments externally 
lunate, -srith an awn at each angle ; end view with thi'ce inflated awned 
lobes. Its rough frond distinguishes it from all the preceding species, 
and the inflated awned lobes of its end view from the following ones. 
Length 1 -856th. 

(B.) — Frond smooth ; angles in end view hroadhj roxmded. 

S. muticum. — Segments elliptic, end view shewing slightly concave 
sides, and 3 to 5 rounded angles. It possesses a mucous covermg, 
frequently indistinct. It differs from S. orhiculare by its elliptic 
segments and numerous coverings. Length 1-6 74th. 

S. orhiculare = Desmtdium orhiculare, (Ehr.) — Segments semi-orbi- 
cular ; end view bluntly triangular. Sporangia orbicular, with 
subulate spines. Length 1-1 037th. 

S. tumidum. — Segments smooth, elliptic, or sub-orbicular ; end 
A'iew bluntly triangular, each angle terminated by a nipple-like pro- 
jection. Frond large, visible to the naked eye ; with a distinct 
gelatinous covering. In both views the margin appears striated. 
Empty fr'ond minutely punctate. Length 1 -200th. 

(C.) — Frond with simple spines, hairs, or (rarely) acute granules ; 
angles in end view hroadhj rounded and entire. 

S. muricatum = Besmidium apiculosum, (Ehr.) — Segments semi- 
orbicular, rough with conic granules ; end view triangular, with 
convex sides and broadly rounded angles. It is larger than S. 
hirsutum, and not hii'sute ; in the end view also, its sides are more 
convex. Length 1 -409th. 

S. hirsutum=Xanthidimn hirsutum, (Ehi".) — Semi-orbicular, rough, 
with numerous scattered hair-like spines ; end view with three 
rounded angles, and straight or slightly convex sides. Sporangia 
orbicular, spines short, and branched at the apex. Length 1 -676th 
to 1 -468th. (P. 12, f. 512.) 

S. teliferum. — Segments reniform, bristly ; end view ti'iangular 
with concave sides, and broadly rounded bristly angles; spines 
scattered. It differs from S. hirsutum in its longer spines, which 
are also fewer, stouter, and in the end view confined to the angles. 



284 DESCRIPTION or \^Polygastrica, 

It is larger than S. Hijstrim, its spines more nnmerons, and the end 
margins, in front view, convex. Length 1 -597th. 

STATJKA.STiirjr Hystrix. — Segments sub-quadrate, sijinous ; end 
view with 3 to 4 rounded angles, each furnished with a few subu- 
late spines. Frond smaller than that of any other species with 
simple spines. End view triangiilar or quadrangular, with concave 
sides and rounded angles. Length l-1075th to 1 -1020th. 

(D.) — £nd view of frond showing four or more toothed hies, which 
a/re either truncate or rounded, lut never elongated into rags. 

S. quadrangulare. — Smooth; segments quadrangular, with a few 
marginal spines or teeth ; end view quadrilateral, with truncate 
angles either emarginate or dentate. Length l-1157th. 

S. sexcostatum. — Large, rough with conic granules which give 
a dentate appearance ; segments in fi'ont view with a toothed angle 
at each side ; end view cii'cular, with 5 to 6 broad, short-toothed 
lobes. The transverse view has a large central opening, sur- 
rounded by a row of large granules. Length 1-66 1st. 

(E.) — Frond smooth ; end view acutely triangular ; with two accessory 
subulate spines to each angle. 

S. monticuhsum. — Eather large segments with a forked spine on 
each side, and at the end about four short, stout, acute projections ; 
end view acutely triangular, with a bifid appendage to each angle. 
Very rare. 

S. pungens. — Each end with about sis subulate spines, directed 
outwards ; each angle in the end view tapering into a spine, which 
has two smaller ones at its base. Its spines are more slender than 
those of S. monticuJosimi, and in the front view are all simple and 
directed outwards. Eare. 

(F.) — Frond smooth; front view witli diverging processes divided at 
the apex. 

S. Irachiatum. — Minute ; front view with thick diverging processes, 
deeply bifid or trifid at the apex ; end view with 3 to 4 rays. Frond 
scarcely constricted at the middle. Sporangia quadrate and spinous. 
Length 1-1 11 1th. 

S. Iceve. — Minute, smooth ; segments with short processes, foi'ked 
at the apex and directed outwards ; end view with 3 to 4 bipartite 
angles ; deeply constricted at the middle, thus difFeiing fr-om S. 



l^esmidiece.] Infusorial animalcules. 265 

hrachiatum. In end view S. Ivcve is unlike any other species. Lengtk 
1- 1220th. 

(G.) — Drond rottgh, with puncta^like granules. 

t ^nd view with entire, rounded or truncate angles or short rays, 

Staurastrum alternans. — Segments rough ; with pearly granules ; 
narrow, oblong, and, from their twisted position, unequal in the front 
view ; end view triangidar, with the angles of one segment entire, 
and alternating with those of the other. (P. 13, f. 16, 17.) 

S. alternans may be Icnown from S. dilatatum and S. punctulatum 
by its unequal segments in the fi'ont, and alternating angles in the 
end view. Sporangia orbicular, with spines forked at the apex. 
Length 1- 1037th. 

S. punctulatum. — Segments rough, with puncta-like granules, 
elhptic, equal; end view triangular, ■with broadly rounded angles 
and slightly concave sides. 

In S. rugidosum the pearly granules are larger and fewer, and at 
the angles appear like little spines. Length 1- 704th. 

S. dilatatum, (Ehr.) — Segments rough, fusiform, equal; end view 
quadrangular, with four short, broad, truncate and entire rays. 
Frond very minute ; deeply constricted at the middle ; the sinuses 
rounded. (P. 2, f. 100, 101.) It differs from S. alternans in not 
being twisted ; its rays also (in an end view) are more truncate. 
Length l-1201th. 

S. margaritaceum = Pentasterias ma/rgaritaeea, (Ehr.) — Eough, 
tapering at the constriction, and having short lateral processes ; end 
view with five or more short, narrow, obtuse rays. (P. 2, f. 104.) 
Length 1-1 176th. 

S. tricorne = Desmidiiim hexaceros, (Ehr.) — Rough, with puncta- 
Hke granules; tapering at each side into a short, blunt, mostly 
entire process ; end view with thi-ee to four blunt angles. 

Var. fb.J — Processes terminated by minute spines. (P. 2, f. 99.) 
It frequently bears a close resemblance to S. alternans from the twist- 
ing of its segments ; the tapering of the segments at their sides is 
its chief distinction. Sporangia orbicular, with spines divided at 
the apex. Length l-1275th to l-948th. 

f f Angles terminated by minute spines, or tapering into slender 



266 BEscRTPTio?! OF \_Poli/ffastriea. 

STAtrRASTRiJM poli/moiyhum. — lloTigli, with minute granules, having 
on each side a short process tipped yrith spines ; end view thix-e to 
six rayed. Much smaller than S. gracile, deeply constricted ; seg- 
ments irregular in form, but generally broader than long. Spo- 
rangia orbicular; their spines few and forked, (P. 13, figs. 20, 21, 
24, 25, 31.) 

The segments are very variable in form, and often resemble those 
of S. tricorne, and S. margaritaceiim, but in these species the processes 
are never spinous. S. polymorphum is smaller and less spinous than 
S. asperum. Length 1-lOOOth. 

S. gracile. — Rough, elongated on each side into a slender process, 
tenninated by minute spines ; end view, triradiate. Frond deeply 
constricted at the middle ; granules in transverse lines on the pro- 
cesses. It differs from S. tricorne in its elongated processes termi- 
nated by minute points. Length 1 -773rd to 1 -539th. 

S. Arachne. — Minute, rough, with minute granules, suborbicular, 
with elongated, slender, incurved processes ; end view with five 
linear rays. Eemarkable by its slender processes. Very rare. 
Length l-1026th. 

S. tatracerum = S. paradoxum (Ehr.) — Minute, rough; front view 
with four slender diverging processes, entire at the apex ; end view 
compressed, with a process at each extremity. Length 1 -2703rd. 
(P. 2. f. 102, 103.) 

S. paradoxum. — Veiy minute, rough ; front view with elongated 
diverging processes, which are minutely trifid at the apex ; end view 
quadi'angular, or sometimes triangular. 
Var. (5.) — End view triradiate. 

Frond generally much constricted ; ends tnmcate ; each segment 
has generally, four elongated processes diverging from those of the 
other segment. S. tetraceriim has but two processes to each segment, 
and these are also undivided, and more slender than those of S. para- 
do.mmi. Length 1-94 1th. 

(H.) Frond spinous or rough, with spine -lilce granules, which are 
incrassated, ema/rginate or divided, 

f Spines minute, inconspicuous, and granule-like. 
S. cyrtocerum. — Rough, with minute granules ; segments in front 
view somewhat triangular, with short incurved (converging) pro- 



Desmidiem.'] iNFrsoRTAt animalcules. 267 

cesses ; deeply constricterl at the middle. End view \^dtll three blunt 
angles. Length 1- 800th. 

Statteastkitm: aspenim. — Segments elliptic or somewhat cimeiform, 
with minute spines, which on the outer margin are usually dilated 
at the end, or forked. Sporangia orbicular; their spines twice 
branched. 

Var. {a.) — -Angles in end view rounded. 

Var. {h.) prohoscideuin (Breb.) — Angles in end view prolonged into 
short rays, terminated by minute spines. 

f f JSnd view acuteh/ triangular ; segments, in the front metv, with a 
forked spine on each side, othericise smooth. 

S. avicula. — Segments with a forked spine on each side; each 
angle, in end view, terminated by a mucro-like spine. Frond very 
minute ; scarcely rough ; the constriction producing wide triangular 
notches. The forked lateral spines of the front view mark the 
species. Length 1-907. Yery rare. 

t f f Lohes in end view broad, emarginate or bipartate. 

S. enorme. — Irregular or quadrate, spinous; end view three to four 
lobed; lobes broad, more or less emarginate or bifid, and terminated by 
spines, which are either simple or branched In the end view the 
broadly emarginate lobes, which, exclusive of the spines, are truncate, 
afford a good specific distinction between it and any other species. 
Length l-601th. 

f f f f Spines numerous, conspicuous ; angles in end view either 
rounded, acute, or extended into processes. 

S. spongiosum. = Besmidium ramosum (Ehr.) — Large, thickly 
covered with short forked spines ; segments semi-orbicnlar, having 
on each side one spine more conspicuous, and more forked than the 
rest. End view triangular, fringed with short notched spines ; 
the sides slightly convex, and the angles rounded. Length l-500th. 
to 1-41 8th. 

S. controversum. — Deeply constiicted, spinulose ; segments elliptic 
or fusiform, with a short process on each side, terminated by minute 
spines ; end view vnth three to four distorted rays. Perhaps a variety 
of S. aculeatum. Length 1-9 72nd. 

S. aculeatum. ^=Desmidium aculeatum (Ehr.) — Spinulose; constrictioiL 
deep, producing a broad triangular notch on each side ; segments 

1 2 



268 DESCRIPTION OF \^Poli/gastrica 

with a short process on each side, termiuatcd by miiuite sjwnes ; end 
"\dew with thi-ee to five straight rays, terminated by spines. Length 
1 -666th. 

Statjeasteum spinosum. — Constriction deep ; segments elliptic, fur- 
nished with a few bifid spines ; lateral spines solitary, larger and more 
forked ; end view triangular, with two to three spines on each side, 
and one terminating each angle. Sporangia orbicular, with nume- 
rous elongated spines, forked at the apex. M. Brebisson considers 
this identical A^vdth Xanthidium furcatum, (Ehr.) Length l-859th. 

S. vestitum. — Eough, with minute emarginate spines; segments 
fusiform ; end view tri-radiatc, each side having two spines, short, 
slender, and often accompanied by other smaller ones. 

Its most distinctive character is the presence of the pair of slender 
forked spines at the middle of each margin. Length l-625th. 



S. pygmmmx (Breb.) — Segments cuneiform ; end view triangular, 
with slightly rounded sides. It is smaller than S. alternans, its 
sides, in the end view, are more convex, and its angles less rounded. 
The sporangium is orbicular and spinous. 

S. ruguhsum (Breb.) — Segments elliptic, denticulate at theii' 
sides ; end view triangular, with the angles broadly rounded and 
denticulate. 

S. seahnim (Breb.) — Segments elliptic, scabrous ; end \'iew tri- 
angular, fiinged with minute emarginate spines. 

S. hacillare (Breb.) — Smooth ; processes capitate ; end view with 
three to five capitate rays or processes. Processes in front view 
stout ; divergent. 

S. capitulum (Breb.) — Segments quadrate, sinuated on each side, 
prominences rough ; end view triangular, with broadly rounded 
angles. Central constriction of frond shallow ; the prominences of 
segments arc rough, with minute granules, which give them a crenate 
appearance. End margin straight. 

S. pileolattim (Breb.) — Quadrilateral, twice as long as broad, 
slightly constricted at the middle ; segments quadrate, tenninated 
by three conical processes, rough, with minute granules. End view 
triangular, angles rounded. 



DesmidiecB.'] infusorial animalcules. 2<5D 

Staurastrum echinatam (Breb.) — "Appears, from. M. de Biebisson's 
drawings, to be closely allied to S. hirsutum, and S. teliferum.'" 

S. crenatum (Bailey) — Segments cnneate ; outer margins crenate ; 
end view with tlu-ee truncate and crenate angles. 

S. hifidum. = Desmidiiim hifidum (Ehr.) — Smooth ; end view with 
thi'ee cloven angles. 

S. eiistcj)Jianui>i. = Desmidiiim eustephanum (Ehi-.) — End view tri- 
angular, with six emarginate spines on the upper surface; each 
angle terminated by a short ray, tipped with spines. (P. 13. f. 3.) 

S. senarium. = Desmidium senarium (Ehi*.) — Ehreuberg's figure 
represents the end view as triangular, the angles terminating in short 
rays, tipped by minute spines ; on each side are two short forked 
spines, and six others on the upper surface. His figure agrees in 
some respects with S. spinosum. (P. 13. f. 7.) 

S. Ehrenbergii (Corda.) — Segments oval ; end view triangular, 
with six terminal and lateral processes, and two centi'al ones, which 
are short, colouiiess, and forked, with diverging apices. Corda's 
figure of the ffont view resembles S. spinosum. 

S. articulatum (Corda.) — Seg-ments oval, their ends furnished with 
a forked process, and laterally with two larger furcate appendices. 
The flat surface has two transverse protuberances, with forked spines. 

S. coronatum = Xanthidium coronatum (Ehi-.) — End view tri- 
angular, and terminating at each angle in three short, diverging 
arms, which are divided at the apex. 

S. (?) minus (Kiitzing.) — Smooth; end view with five slender 
acute rays. 

S. glabncm = Desmidium glahrum (Elu\) — Smooth; end view tri- 
angular, each angle terminated by a mucro-like spine. This species 
is probably identical with S. auricula. 

S. granulosum = Desmidium granulosum (Ehr.) — Known only by 
name to Mr. Ealfs. 

S. ghhuJatum. — Segments fusiform, capitate; end Adew globular, 
each angle terminated by a granulated knob. 

Genus Pesxasterias (Ehr.) — The five-rayed Desmidiecn. — Lorica 
simple, univalve, five-sided, with a central aperture ; free, but some- 
times developed in chains. 

This genus, instituted by Elu-enberg, contained, in 1838, but one 
species, called P. margaritacea, the Staurasirum tnargaritaceum (Ralfs), 



270 DESCEIPTION OF {Polygastrica. 

but subsequently (1840) two other species were added, which, from 
the given characters, we presume to be Staurastra, but shall describe 
them in Ehrcnberg's own words. 

PEJfTASTEEiAS oUusa. — Corpusclcs solitary, sub-orbicular, penta- 
gonal, green ; laterally, ovate oblong, smooth. Diameter 1-1 150th. 

P. radiata. — Corpuscles in pairs, with elongated rough rays 
equalling their diameter, rays connivent ; ovarium green, in five 
segments (quinquefid). Entii'e diameter l-860th. 

Genus DiDYMocLAnoif (Ealfs.) — Frond simple, constricted at the 
middle, angular, each angle having two processes, one lateral, and, 
in front view, nearly parallel to the adjacent one of the other seg- 
ment, the other superior and divergent. 

This genus is closely allied to Staurastrum, but differs by each 
angle of the segments giving rise to two processes, one beneath the 
other; whereas, in Staurastrum, the process, when present, is 
solitary. 

D. furcigerus. 

Frond comparatively large, rough, with pearly granules, which, 
being arranged on the processes in tranverse Irues, produce a crenate 
appearance on their margins. In the front -view, the processes are 
elongated, stout, tapering, bifid at the apex. Length, exclusive of 
processes, l-547th. Breadth l-555th. 

Var. («.) — End view triangular. 

Var. {b.) — End view quadi-angular. 




^^ '^W5^ 




Front view. End view. 

D. cerherm (Bailey). — Small, deeply constricted, segments three- 
lobed ; lobes with four teeth, two of which project. Lakes in 
Florida. 

D. longnpinum (J^qxIgj .) — Large, smooth, triangular, with two long 
ppines at each angle. Lakes in Florida. 

The two last species are not veiy nearly allied to each other, nor 



DesmidiecE.'] infusoeial animalcules. 271 

to the typical D. furcigerus, yet they agree better with the verbal 
characters of the genus than with those of any other known to 
Dr. Bailey ; therefore, he refers them here pro\'isionally. 

Genus Tetmemokus (Ralfs.)— Frond simple, elongated, straight, 
cylindi-ical, or fusiform, slightly constricted at the middle ; segments 
emarginate at the end, but otherwise quite entire. The frond is 
elongated, as in Penium, but differs in its emarginate ends; the 
same character and the elongated frond separates it fi'om Cosmarmm. 
From Eiiastrum, with which it agrees in the emarginate extremities, 
it differs in being cylintbical or nearly so, and in the segments beuig 
neither lobcd nor siiiuated ; the fronds are also free fr-om inflated 
protuberances. 

T. Bnhissonii. — In front view with parallel sides, but in lateral 
one fusiform ; ends without any projecting processes ; pimcta in 
longitudinal lines (P. 13. f, 12, 13.) 

Var. (J.) turgidus. — Larger; constriction greater ; segments some- 
what inflated. Frond four to six times longer than broad. The endo- 
chrome is dark green ; its large vesicles in a single central row. 

T. IcBvis. — Somewhat tapering in front view; ends truncate; 
lateral view fusiform ; puncta none or very indistinct ; four to six 
times longer than broad, constricted at the middle. Length 1-3 74th. 

The process of fo]-ming the sporangium is interesting, as it exhibits 
a striking similarity to the change during the formation of similar 
bodies in Staurocar2)us among the ConjugattB. In Staurocarpus, after 
conjugation, a subquadi-ate cell is formed, within which the endo- 
chrome is collected. The latter is at first of the same figure as the 
cell, but in at least one species, is at length condensed into a compact 
globidar body, and in every species the cell >vdth the contained 
sporangium, finally separates fi'om the filaments with which it is 
connected. In this separate state I can discover no character by 
which to distinguish the sporangium of Tetmemorus from one be- 
longing to a species of Staurocarpus. Length. 

T. granulatus. — Fusiform both in the front and lateral views, and 
ending in a colouiiess projecting lip-like process ; about six times 
longer than broad ; very slightly constricted. Empty frond with 
scattered puncta ; near the central constriction they form one or two 
tranverse lines in each segment. 



272 DESCRIPTION OF [Poli/gastrica 

It may be distinguished from the preceding species by the front 
and lateral views being similar. Length 1-1 33rd. 

Gemis PENrtJM (Breb.) — Frond simple, elongated, straight ; not, 
or but slightly, constricted ; segments entire ; the opposite margins 
similar ; and suture either indistinct or wanting. 

It differs from Clostermm by its straight fi'onds, with similar oppo- 
site margins ; from Tetmemorus by the absence of a terminal notch, 
and from Cosma/rium by its more elongated frond, and its less marked 
constriction at the junction of the segments ; yet the cylindrical 
species of Cosmarium closely approach to this genus, and C. turyidmn 
and C. attenuatum are, at least, as much elongated as Penium 
tnmcatum. 

Some species of Penium are smooth, and, like Closterium, 
have the endochrome arranged in longitudinal fillets, and at each 
extremity of it a globule containing mo\'ing granules. Other species 
have a granular surface, and there are two smooth and truncate, 
which some botanists have refeired to the Pahnellece. 

As in other instances, we follow Mr. Ralfs division of this genus. 

* Empty frond either striated or granulate, generally reddish. 

P. margaritaceum = Closterium margaritaceum (Ehr.) — Cylindiical, 
with rotundato truncate ends; pearly granules in longitudinal 
series. 

Var. {a.) — Fusiform, constricted at the middle ; gi-anules distinct, 
giving a denticulate appearance to the margin. 

Var. (l.) — Linear, scarcely constricted at the middle; denticulate 
on the margin, somewhat scattered near the suture. 

Var. {c.) punctatum. — Linear, neither constricted at the sutui'e, 
nor denticulate at the margin ; granules appearing like puncta. This 
last form agrees best with Ehrenberg's figure of Closterium margari- 
taceum, but it is not denticulate at the margin. 

Length of frond, in faj 1-1 56th; in fcj 1-1 69th (P. 13, f. 14.) 

The sporangia are orbicular. (P. 13, f. 15.) 

P. oylindrus = Closterium (}j cylindrus (Ehr.) — Cylindrical ; ends 
rounded truncate, rough, with pearly scattered granules. Length 
l-49:nd. 

* * Frond smooth, colourless. 

\ Sporangium situated between the deciduous cells. 



DesmidiecB.'] infusorial animalcules. 273 

Penitjm: digitus = Cloderium digitus, and Polysolenia Closteriiim. 
(Ehr.) — Smooth, elliptic-oblong, with rounded ends; fillets obscure, 
undulated, inteiTupted only by a transverse band at the suture. 
Terminal globules wanting, or very indistinct. Length 1-8 1st. 
Three to five times longer than broad. 

P. internqyttnn. — Smooth, cylindi-ical ; extremities conical, -^^th 
rounded apices; fillets three to foiu- strongly marked, interrupted by 
three transverse bands. Ends colourless ; each occupied by a large 
globule containing moving granules, as in Closteriiim. Length 1-11 6th. 
Foui' to six times longer than broad. 

P. closteroides. — Smooth, fusiform or lanceolate ; longitudinal fillets 
and terminal globules distinct. Ends obtuse ; vesicles in a single 
longitudinal row. Length l-92nd. Six to ten times longer than 
broad. 

P. truncatum. — ^^Veiy minute, smooth, cylindrical, with truncate 
ends ; sporangia orbicular, easily detached from the conjugated 
fronds. Two to three times longer than broad. Has a transverse 
pale band, but, when empty, exhibits no suture. Length 1 -969th 
to l-555th. 

P. Jenneri. — Smooth, cylindrical with rounded ends ; sporangium 
orbicular, situated between the conjugating fr-onds, which are 
deciduous. It agrees in size and form with P. Brelissonii, but differs 
in the form of its sporangia. The conjugating fronds do not open 
and gape at the sutui'e, as is usual in the Desmidiece, but couple by 
small and distinct cylindrical tubes, like many of the Conjugatce. 
Length 1-8 10th. Two to four times longer than broad. 

f t Sporangium permanenthj attached to the conjugated cells, at first 
quadrate, then orbicular ( Cylindrocystis.) 

P. BrShissonii. — Smooth, cylindrical, with rounded ends ; sporan- 
gium at first quadrate, but finally orbicular; conjugating fronds 
persistent. Minute, often congregated into a mucus stratum on wet 
mud. The transverse pale central band, which, in the Besmidiem, 
indicates the line of junction of the segments, is less conspicuous 
here than in any other species of the family. Length 1 -637th to 
l-404th. 

Genus Docidium (Brebisson.) — Frond simple, straight, much elon- 



274 DESCEIPTION OF \^Poli/gastrica. 

gated, linear ; consti'ictcd. at the middle ; tiamcate at the ends ; seg- 
ments usually inflated at the base. A suture is generally very dis- 
tinct, in a line "with the constriction. This genus, like Closterium, 
has terminal globules containing moving granules, and its vesicles 
are either scattered or an-anged in a single longitudinal row. It 
differs from Closterium in its straight fi-onds and constricted middle ; 
and from Penium, it may be known by having a distinct constriction 
at the middle, and more elongated fronds. 

DocrDiUM iiodulosiim. — Large, stout, segments foiu* to six times longer 
than broad, constricted at regular intervals, so as to produce undulated 
margins ; sutui'e projecting on each side. D. nodulosum difi'ers from 
D. constrictum and D. nodosum, in its more numerous but slighter 
constrictions. 

D. truncatum. — Large, stout ; sutiu^e projecting on each side. Its 
distinctive marks are, the more attenuated extremities and the soli- 
tary inflation at the base of each segment, so that its mai'gins are 
not imdulated. Length l-81st to l-72nd. 

D. cla/vatum. — Segments many times longer than broad, with a 
single inflation at the base ; ends clavate, but truncate ; suture not 
projecting. Vesicles small, few, and arranged in a single longitudinal 
line. Empty frond minutely punctate. Length l-65th (P. 13. f. 9.) 

D. Ehrenlergii ^= Closterium Trabecula (Ehr.) — Segments elon- 
gated, with two or three slight inflations at the base ; ends truncate, 
bordered by minute tubercles (P. 13. f. 8 and 11.) 

Var. (l.J — Erond rough, with minute granules. Frond as long 
as those of D. noduhsum and D. truncatum, but far more slender ; 
constricted at the middle; suture strongly marked but not projecting. 

D. haculum. — Segments very slender, having a solitaiy and con- 
spicuous inflation at the base, otherwise linear ; vesicles in a single 
series. Suture strongly marked, not projecting. Length 1-1 11th. 

D. minutum. — Small ; slender, slightly constricted at the middle ; 
segments lineax-, not inflated; vesicles iu a siagle series. Length 
l-212th. 

D. ? asperum. — Slender, twelve or more times longer than broad, 
cylindrical, rough ; Mr. Ralfs has seen neither vesicles nor terminal 
globules. Unlike all the true JJocidia, this has neither constriction 



DesmidiecB.'] inftjsoeial animalcules. 275 

nor suture : but it is not luilikc the separated joints of a species of 
Mougeotia, but the dilated truncate ends and roughness produced by 
minute granules distinguish it. Length l-97th to l-64th. 

Docn)ixT.M coronation. — Stout : segments inflated at the base, and 
bordered by tubercles at the end. 

Tliis species differs from D. nodulosim, which it otherwise re- 
sembles, by ha%'iug the ends bordered with minute but distinct 
tubercles. 

D. nodosum. — Stout; segments with four prominent nodes, sepa- 
rated by constrictions ; end view crenate. It is one of the largest 
species in the genus. 

D. constn'ctum. — Stout; segments with moderately deep constric- 
tions, which separate four equal, gently ciu-ving prominences ; end 
view entu'e. 

This species, says Dr. Bailey, is at once distinguished from D. no- 
dosum, by the cross section of the nodes being a simple circle instead 
of an indented one ; an end view of the latter proving each node to 
be not a simple swelling, but really a whorl of tubercles. 

D. verrucosum. — Segments with numerous whorls of small pro- 
minences, which give the margins an undulated appearance ; all the 
imdulations equal. 

D. verticillaUim. — Segments with numerous whorls of tooth-like 
projections; ends with three bidentate processes. 

These processes are so unlike what we find in other species of 
JDocidium, that Dr. Bailey is disposed to fonn a new genus for the 
reception of this species. 

D. crenulatuni = Closterium crenulatum (Ehr.) ; and is, according 
to Bailey, identical with Docidmm nodulosum. 

D. hirsutum (Bailey.) — Segments many times longer than broad, 
slightly inflated at base, surface hirsute. A small species resembling 
D. Hhrenbergii va. form, strongly hii'sute on its outer surface. Lakes 
in Florida, at Enterprise. 

D. xmdulatum (BaUey.) — Segments eight to ten times longer than 
broad, constricted six to eight times at regular intervals throughout 
their entire length, with the base and ends crenate. Smaller than 
D. nodulosum, with more frequent and deeper constrictions. The same 
characters distinguish it fr'om D. nodosum and D. constrictum. 



276 DEsCEiFTiON OF {^Pulygastrka. 

Genus CLOSTErvruM. — Frond simjjlc, elongated, lunutely curved or 
arcuate, entire; the junction of the segments marked by a pale 
transverse band, but no constriction. 

In the usual position, the opposite margins of the fusiform fronds 
are always more or less dissimilar, the upper one being convex, and 
the lower, inclusive of the ends, straight, or more commonly concave ; 
the lateral view is straight, and has both margins similar. As happens, 
in the allied genera, the frond is composed of two segments which 
finally separate, and allow the escape of the endochrome. The seg- 
ments are entire, without spines, processes, or inflated protuberances. 

The endochi'ome is green, with darker longitudinal bands or fillets, 
the number of which varies in different sjiecies. The diaphanous 
vesicles, conspicuous in most of the species, are either scattered, or 
arranged, with more or less regularity, in a single longitudinal series. 

At each extremity of the endochrome, even in its earliest state, 
there is a large hyaline, or straw-coloured globule, which contains 
minute granules in constant motion. This globule disappears in 
the dried specimen. 

A distinct circulation (rotation) has been noticed in several species. 
It is said to occur only in species obtained from water, and not in 
those taken from moist ground. The empty frond is striated in some 
species, and smooth in others. The colour' and firmness of the cover- 
ing differs in different species. Some are quite coloiu-less, flexible, 
collapsing when dried, and in general allowing the endochrome to 
escape by a merely partial separation of the segments. These species 
are never striated. In other species the fronds arc more or less straw- 
coloured, or even reddish. The deeper the colour, the fii'mer the 
fi'ond. The segments in such, separate entu-ely from each other. 
Some of the striated species, even when submitted to the action of 
nitric acid or fire, retain theu- form and markings. In the coloured 
species the extremities are generally darker than the rest of the 
frond." 

Even in the firmest species the frond becomes flattened in drjdng, 
its breadth at the centre increases, and the ends appear more 
attenuated than in the living state ; a fact to be borne in mind in 
describing or drawing a dried specimen. 

In Closterium the process of conjugation appears to be nearly the 



Desmidieoe.'] infusorial animalcules. 277 

same as in the Conjnriatce. Two fronds unite by means of pro- 
jections arising at the junction of the two segments, and then the 
newly fonned portion continues to enlarge until the original seg- 
ments ai'e separated by a coll of an ii-rcgular four-sided figure. The 
contents of the fronds, being collected in this cell, become a dense 
seed-like mass, wliich is sometimes globular, resembling the Spo- 
rangium of 3Iongcotla, and sometimes square, like that of Stauro- 
S2)ennnm. The ne^ly-formed cell is thinner, and generally paler 
than the segments of the frond ; in some species it looks like a pro- 
longation of the segments, and in others these are so loosely attached, 
that their coimection is scarcely perceptible. (P. 13. f. 5, 6.) 

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

The Rev. W. Smith has presented to naturalists an excellent ac- 
count, with a series of illustrative engravings, of the phenomena of 
conjugation in Closterium Ehrenhenjin, which he states differs from 
those in other Closteria generally, and indeed from those of any 
other of the Besmidiccs. (AnnalNat. Hist. vol. 5, 1850.) 

" The first phenomenon is an alteration in the granular condition of 
the endochrome. This, from a light yellowish green, passes to a 
much darker shade, and the larger granules, or " diaphanous vesicles" 
of Ealfs, which were originally few in number, and arranged in a 
somewhat irregular longitudinal series (P. 18, f. 10), become exceed- 
ingly numerous and pervade the entire frond. While this change is 
about taking place, the fronds approach in pairs, approximating by 
their concave surfaces, and finally coming into such close neighbour- 
hood that their inflated centres are in contact, and their extremities 
slightly overlapped. (P. 18, f. 11.) In a short time, probably in 
the course of twenty-four hours, a remarkable change takes place, 
both in the appearance and condition of the fronds ; a mass of 
delicate mucus is secreted around the approximated fronds ; these 
remove to a little distance from each other, undergo ' self-division ' 
and present altogether an irregular oval figure, the outline of which 
is formed by the periphery of the mucus, the four divisions of the 
fronds being placed in the middle in a somewhat quadrilateral 
manner. (P. 18, f. 12.) During the progress of cell-division, the 



278 DESCiiiPTioN OF \ Polygastrica. 

internal membrane of the cell- wall becomes enlarged at the suture or 
line of separation, and projects in tbe form of an iiTegular cone, with 
a blunt or rounded apex forming a beak, whose side view presents a 
triangular outline. This beak becomes filled with cndochrome, 
either by the dilatation or increase of the contents of the half-frond, 
and the divided frond assumes the appearance of one with two im- 
equal segments (f. 12.) being what M. Morren calls "a Closterium 
of two unequal cones." On these membranous expansions, at the 
concave surfaces of the fronds, and close to the original sutm'es, there 
appeal', almost simultaneously with the formation of the beaks, two 
circular projections, which, rupturing at their apices, give egi-ess to 
the delicate sacs which enclose the endochrome, and which, drawing 
with them their contents, and meeting with the endochrome sacs 
emitted through similar projections from the other half fronds, form, 
by their connection, irregular masses, which quickly consolidate and 
assume the appearance of perfectly, circular, smooth, dark-coloured 
balls, the sporangia of Ealfs and seminules of Mon-en. (P. 18, 
f. 13 and 14.) 

" The discharge of the endochrome and formation of the sporangia 
are accomplished with much rapidity, and may often be seen taking 
place in the field of the microscope, the whole operation not occupy- 
ing more than a few minutes. It -wall be seen from an inspection of 
the figures, that during the formation of the sporangia there appears 
to be a second development of mucus in the form of rings around the 
reproductive bodies ; this is probably only the efi'ect of the pressure 
produced by the growth of the sporangia on the mass of investing 
mucus. It will also be seen that the pale transverse band adopted 
by Ealfs as a characteristic of the genus Closterium, and which in 
figs. 10 and 11 occupies the centre of the undivided frond, is, upon 
self-division taking i)lacc, removed a little towards the extremities 
of the half fronds. The reason, as weU as the cause of this motion, I 
am unable to explain, but it seems to confirm the propriety of adopt- 
ing the band itself as a permanent and important character. 

" With regard to the subsequent changes which take place in the 
sporangia, the time which elapses before they produce young fronds, 
and the mode in which such evolution of a fresh race is accomplished, 
I have not been fortunate enough to ascertain with any certainty. . , . 



Dcsmidiece.'] infusortal animaicules. 279 

"M. Morron contoiuls that a sporang-iiim becomes converted into 
a single frond, and gives a scries of figures in illustration of the 
changes -which the sporangium undergoes until it becomes " a Clos- 
termm of two unequal cones." (P. 18, figs. IG, 17, 18, 19.) Now 
as this form is the result of the self-division of the ordinary frond, 
and invariably precedes conjugation, I am disposed to think M. 
Morren has mistaken fronds thus divided, and aftci-wards thrown out 
of their relative positions, for modified sporangia. 

Self- division, in the case before us, seems only to accompany con- 
jugation, and ^vill not, as in the other Desmidiem, accoimt for the 
existence at certain periods of vast multitudes of the fronds 

" I may remark, that in a generic arrangement, based upon the 
reproductive organs, Clostermn Ehrcnhergii will stand apart fi'om all 
the other Desmidiece. In it alone a pair of conjugating fronds pro- 
duce two sporangia. It is, however, allied to others of the present 
genus thi'ough C. lincatum, the sporangiimi of wliich, according to 
Mr. Ealfs, is binate, and shows a disjiosition to separate into two 
parts." 

"Another mode of increase, analagous to the propagation of 
Zoospores in Algag, has been assigned to the Besmidiem, and it has 
been alleged that the endochrome escapes in the form of zoospores, 
and becomes transferred into new fi'onds. M. Morren not only 
affirms this to be the case, but gives a figure illustrative of the 
conversion of these zoospores, or as he terms them ' propagules,' into 
new fronds." (P. 18, f. 15 ) 

Mr. Ealfs states, that " As there is no constriction in Closterium, 
the process of division is less evident. It is best seen in the striated 
species, in which the central suture is most distinct. The transverse 
line becomes double, and, by the iutermediate growth, the frond at 
length, consists of three portions, as the newly-formed central one 
continues to elongate, another transverse Kne becomes visible at its 
middle where a complete separation at length takes place. At first, 
however, the new segment is often merely a rounded protuberance, 
and the fi-ond is consequently unequal ; and when it is perfected, 
if the covering is a coloui'ed one, the newer segment can still be dis- 
tinguished by its greater paleness. 

" The striated species, besides the central suttu-e, frequently have 



280 DESCRIPTION OF \^Polygdsiriea. 

otlicr transverse lines that divide the segments themselves into two 
or more portions. (P. 13, f. 6.) 

" Cloderium may be distinguished from all the other genera of 
the BesmidiecB by its elongated, curved, entire, and attenuated 
fronds." 

The discussion as to the vegetable or animal nature of the Closteria, 
and Ehrenbcrg's views, are given at page 179, and in the inti'oduction 
to this section of the family Bacillaria. 

1 . — Sporangium orliculor, situated between the conjugating fronds and 
hut slightly connected with them ; fronds never rostrate fClosteriumJ. 

f Frond semilunate, or semildnceolate, tapering from the middle, the 
lower margin straight, (or nearly so), and inclined upioards at the end. 

C. lunula (M.) — Large, stout, smooth, semilunate; lower margin 
nearly straight, inclined upwards at the rounded ends ; vesicles nu- 
merous, small and scattered. Fillets several ; three more distinct 
than the rest. Empty frond colourless, without markings, and its 
suture indistinct. Length l-62nd. 

C. acerosum. — Linear-lanceolate, gradually tapering, ends conical ; 
fillets distinct ; vesicles in a single series j empty frond colouiiess ; 
striae none or indistinct (P. 1, f. 63, 64, 65.) 

Yar. fh.J — More elongated; strige more distinct. Length l-170th 
to l-48th. 

C. lanceolatum. — Semilanceolate, gradually tapering ; ends sub- 
acute ; fillets several ; vesicles in a single series ; empty frond colour- 
less. Length l-64th. 

C. turgidum. — Lower margin slightly concave, inclined upwards at 
the rounded ends ; upper margin with a depression near each ex- 
tremity ; empty frond coloiu-ed ; striae numerous, fine but distinct. 
Vesicles in a single row ; fillets three or more ; suture distinct. 
The curved and rounded ends are characteristic Length l-39th 
(P. 1. f. 66.) 

■f- f Frond smooth, crescent-shaped, rapidly tapering from the middle- 

C. Ehrenhergii = C lunula (Ehr.) — Smooth, stout, crescent-shaped ; 
when empty, colourless ; lower margin very concave ; inflated at the 
middle; ends rounded ; vesicles numerous, scattered. Length 1 -68th. 
(P. 8. f. 10.) 

C. moniliferum. — Smooth, crescent-shaped, when empty, colourless; 



DesTnulieee.'] infusohial animalcules. 'iSl 

lower margin inflated at the middle, very concave ; ends rounded ; 
vesicles large, in a single row ; fillets several ; suture absent. It 
may always be distinguished bj' the inflation at the middle of its 
lower margin ; its single row of vesicles separates it from C. Ehren- 
hergii. Length l-75th to l-60th, 

Closterhim Jenncri. — Small, crescent-shaped, generally sUghtly 
constricted at the suture; when empty, colouiiess; ra^ndly tapering; 
ends very obtuse ; vesicles in a single series. Length l-281th. 

C. Leibleinii. — Smooth, crescent-shaped ; extremities much attenu- 
ated and sub-acute at the apex ; lower margin slightly inflated at the 
middle ; vesicles in a single row, large. 

Var. (J.) — More slender, the central inflation less evident ; empty 
frond of a deeper colour, and its central suture distinct. Length 
l-291th. to l-165th. (P. 13. f. 1. and 5.) 

C. Biauce (Ehi*.) — Smooth, slender, crescent-shaped ; extremities 
tapering ; apex sub-acute ; lower margin not inflated ; vesicles in a 
single series. The empty frond of a pale straw colour, Avith a central 
transverse sutui-e. It is less curved than preceding. Length 
1-1 43rd. 

Iff Frond nearly straight, scarcely attenuated- ; ends truncate ; 
longitudinal stria none or indistinct. 

C. didymoticum. — I^early straight, broadly linear; extremity 
slightly tapering ; ends truncate ; reddish ; fillets obscure. 

Var. («.) — Empty frond divided by three transverse lines or 
sutures. Rare. 

Var. (i.) Baillyanum. — Smaller, with a sutm'e only at the middle. 

C. didymoticum may be kno-wn from all the preceding species, by 
its straight unstriated frond, combined -with truncate ends. Length 
of var. {h.) l-65th. 

f t t t Empty frond distinctly striated, mostly coloured. 

C. attenuatum (Ehr.) — Cmwcd, attenuated ; suddenly contracted 
at the end into a conical point ; empty frond reddish, faintly striated. 
Kather larger than C. striolatum. The sudden contraction of its 
extremities is characteristic. Length l-57th. 

C. costatum. — Stout, semilunate, tapering from the middle ; ends 
obtuse ; strife few and conspicuous ; suture solitary. Fillets obscure j 
vesicles in a single row. Empty frond reddish. Length l-75th. 

u 



282 DESCEiPTiON OF {Polygaslrica. 

Clostertitm striohtum (Ehr.) — Closely but distinctly striated, 
crescent-shaped, tapering from the middle ; sutures generally three, 
never more ; ends very obtuse ; lower margin never inclined upwards 
at the ends. Length l-80th to l-68th (P. 13, f. 2 and 6.) 

C. mtermedium. — Slender, sKghtly curved, tapering; strias dis- 
tinct, not crowded ; sutures usually more than three ; ends truncate. 
Its most remarkable feature is the number of its sutures, whicli 
exceeds that of any other species. Length l-77th to l-54th. 

C. angustatum. — Sublinear, curved, scarcely attenuated ; ends 
truncate ; strise few, very distinct and prominent ; sutures usually 
three. Vesicles in a single row ; fillets obscure. Length 1-60 th. 

C. juncidtim. — Very slender, linear, straight, except the extremi- 
ties, which are slightly attenuated and curved downwards. 

Var /'b.J — Stouter, and less elongated ; its colour, when empty, 
deeper, and its strise more conspicuous. Length of {'a J 1- 111th to 
l-69th. Length of ('bj l-144th. 

2. Frond striated, much elongated, gradually tapering, scarcely ros- 
trate ; sporangium hiloied, situated between the conjugated fronds. 

C. lineatum (Ehr.) — Stiiated, slender, long, curved, gradually 
tapering into the conico-rostrate extremities ; lower margin slightly 
inflated at its centre ; fillets three or more, frequently obscure ; vesi- 
cles in a single row ; one or more transverse lines at the centre ; 
longitudinal striae numerous. 

Var. (b.) — Longitudinal striae numerous. 

C. lineatum connects the rostrate with the other striated species, 
as in general aspect it agrees with some of the latter, and in its 
inflated centre and tapering extremities with the former. 

The fronds approach and couple in the usual manner ; but instead 
of the contents of both fronds uniting in the ordinary manner into 
a single body, a bilobed body is produced, not unlike a species of 
Cosmarium. Though called bilobed, Mr. Ralfs regards the sporan- 
gium as bitiate, being readily separable at the constricted line of 
junction, (page 279.) Length 1 -48th. 

3. Frond either rostrate or minute, colourless and acicular; sporan- 
gium cruciform. { Stauroceras, Kutzing.J 

I Frond striated, tapering at each end into a distinct beak. 

C. lialfsii. — Stout, striated, curved, rapidly attenuated into linear 



t>esmulie(P.'\ iivFrsoRiAL animalcules. 283 

beaks, -vrhicli are shorter than the ventricose body. Vesicles dis- 
posed rather ii-reguhirly in a single row ; fillets generally obscure ; 
empty frond reddish. Length l-79th. 

Closterifm rostratum (Ehi'.) — Closely striated, tapering at each 
end into a setaceous curved beak, which is about eipial in length to 
the ventricose body. Fillets obscure ; vesicles in a single row. 
Empty ft'ond coloiuicss or straw coloured. Length l-69th. 

C. setaceiim (Ehi*.) — Very slender, finely sti'iated, narrow lanceo- 
ate, tapering at each extremity into a very long setaceous beak, 
which alone is curved ; vesicles none or obscure. Fillets none. 
Sporangium quadi'ate or cruciform (P. 1. f. 67.) Length 1-1 16th. 

Ehrenberg discovered this species in May, 1832 ; and, in 1835, ob- 
served the process of copulation (conjugation.) On the issuing forth 
of the green matter separation took place into four instead of two 
portions, and the green matter formed itself into a flat eight-cornered 
body, with a bright spot in its centre, and granular contents. (See 
figau'e on right side of group 67, Plate 1.) 

f f Frond minute, tapeiing, not rostrate ; empty fi'ond colomioss 
and Avithout markings. 

C. cornu (Ehi-.) — Smooth, minute, curved, very slender; extremi- 
ties slightly attenuated ; ends obtuse ; vesicles none or indistinct ; 
sporangium quadrate. 

Var. fh.J — Frond more turgid. Length 1-1 40th. Length of 
var. fbj 1 -226th. 

C. acutum.. — Curved, gradually tapering at each extremitj^ ; ends 
more or less acute ; empty fi'oud colourless, without markings. 

Var. fa. J — Six to twelve times longer than broad; vesicles ob- 
scure ; fillets none ; ends sub- acute. 

Var. fb.J — Ten to twenty times longer than broad, tapering at each 
extremity into a very fine point. Length 1-1 77th. 

C. cuspidatum (Bailey.) — Smooth, crescent-shaped ; ends murro- 
nate. It differs from every other species of the genus in having 
each end tipped by a spine or mucro- 

C. cucumis (Ehr.) — Smooth, stout, semilunate ; ends broadly 
rounded. In form it resembles C lunula, but is stouter in proportion 
to its length, and has its ends more rounded. 

C. Tliurcti. — Smooth, crescent-shaped ; ends sub-acute ; margina 
unconnected at the suture ; vesicles in a single series 

c 2 



284 DEscKiPTiON OF {Tolygasirk'a. 

CtosTEnrcTM; arciiatum. — Smooth, slender, crescent-shaped, ends 
obtiise, scarcely notched. 

C. Venus (Kiitzing.) — Mr. Ealfs is unable to discover any characters 
sufficient to distinguish it from C. Diame. 

C. amhhjonema (Ehr.) — Stout, linear, slightly curved, twenty times 
longer than broad ; ends roiinded. 

C. uncinaticm. — Slender, finely and closely striated ; extremities 
tapering to a sub-acute point, and suddenly curved downwards. 

C. decussatum. — Stout, finely and closely striated, slightly curved, 
gradually tapering; extremities slender, but obtuse at the apex. 
It seems to diiFer from C. turgichim in its more tapering extremities. 

C. ttirgidulum. — Stout, curved; extremities slender, gradually 
tapering ; striee few, conspicuous. It differs from C. costatum in its 
more elongated extremities. 

C. oMiisangulum. — Crescent-shaped; four- sided ; angles rounded; 
ends rounded. Empty frond transparent, colourless, with a narrow 
central suture, 

C. incequale (Ehr.) — Miaute, semi-lunate ; extremities unequal, 
conical, ends acute ; striae prominent ; vesicles scattered. 

C. quadrangulare. — Long, thin, quadrangular, the angles acute ; 
endochrome deep gi-een ; sutures several, oblique ; ends rounded. 

C. gracile. — Slender, smooth, lanceolate, gradually tapering into 
short beaks, which are curved downwards. It diiFers from other 
rostrate species in its smooth frond. Its beaks are shorter than 
those of C. rostratum, and C. setacetim, and it is less inflated. 

C. tenerrimuni (Kiitz.) — Mr. Ralfs states he can perceive, in Prof. 
Kutzing's drawing, no character by which it can be separated from 
C. acufum- 

Genus Spirot.^nia (Brebisson.) — Frond simple, elongated, cylin- 
drical, or fusiform, straight, entire, not constricted at the middle ; 
ends rounded; endochrome spiral, as in i^^«(?»m; this circumstance 
distinguishes it from every other genus. It differs from Tefme- 
morus in the entire extremities, and absence of central constriction ; 
and, in the latter, likewise from Chsterium. The extremities are 
also without globules. It closely resembles Zygnema in its endo- 
chrome, but docs not form a filament, the ccUs dividing in the 
manner of the Des^nidiece, but obliquely as in Scenedesmus. In Spi- 
rotcenia complete division of the cell is prior to the division of the 



Desmidiece.'] infusorial animalcules. 285 

gelatinous covcriug, "whicli thus retains the two newly-partccl cells 
together for some time longer, a fact wliich convincingly proves that 
this genus belongs to the Desmidiece. 

SpiiioTiENiA eondcnsata. — Endochrome, a single, broad, closely 
spiral band. Frond bright yellow-green, cylindrical. Length 1-20 8th. 
(P. 13, f. 4.) 

S. ohscura. — Endochrome at first in several slender spiral threads, 
afterwards uniform. Frond dark green; extremities attenuated. 
Length 1 -247th. to 1 -226th. 

Genus Ankisteodesmus {Corda.) — CeUs elongated, attenuated, en- 
tire, fasciculated. Cells fusiform or crescent-shaped, with no con- 
etriction. They resemble Closterium, except in their aggregation. 

A. falcatus = X/mthidium (?) dijforme (Ehr.) — Cells very minute, 
slender, crescent- shaped, fasciculated in irregular bundles, the indi- 
viduals of which, having their convexity turned inwards, diverge at 
each exti-emity of the bundle. Length of cell 1 -549th. (P. 2. 
f. 3 ; and P. 12. f. 513. 514.); the two latter fossil specimens. 

A. fusiformis (Corda.) 

A. convolutus (Corda.) 

Genus Pediasteum (Meyen.) — Frond plane, circular, composed of 
several cells, which form by their union a flattened star, and are 
generally arranged either in a single cu'cle, or in two or more con- 
centric ones ; marginal cells bipartite. The cells are combined into 
a frond by a mucous matrix, which is generally colouiiess and con- 
stitutes hyaline interstices. 

" The flat star-like fronds of Pediastrum are sufficiently cha- 
racteristic. It is far more difficult to distinguish its species. 
Ehi-enberg relies chiefly on the number of the circles, but this 
character cannot always be depended on ; for it has been observed 
that the number of cells is in the same species liable to great 
variation; so also are the number of circles, and the number of 
cells in the inner circle. Though so uncertain, we must still, for the 
most, depend on the above characters in discriminating between 
nearly allied species. Ehi'enberg, having relied almost entirely on 
the number of circles, and the cells in each, has neglected the form 
of the cells, and, consequently, his species are intermixed- transition- 
states of some being referred to others." 



28G DESCRIPTION OF {Fohjgostrica. 

The process of division takes place at the notch, as in other 
BesmidiecB. 

M. Thuret has recently advanced the statement, founded on his 
personal observation, that the fronds of Pediastrwn elliptmim de- 
vclope vrithin their cells exact but miniite copies of themselves ; 
which, in course of time, assume the size and all the characters of 
the parent. He says, " all doubt was removed fi'om my mind, when 
I witnessed the escape of four young ones from the cells of an old 
frond : the cells opening and emitting by degrees, often by jerks, the 
young Pediastnmi, enveloped in its gelatinous mass." Cinn. des 
Sciences Nat. 1850.) 

The old cells are left empty and colourless. In fi'onds not very 
young, a clear nncleiis, refracting light strongly, was discernible ; in 
the very young, this is not visible, and in the old fronds very indis- 
tinct. M. Thuret believes it to be concerned in the formation of the 
cell, or the reproduction of the species. 

This method of development (M. Thuret remarks), rccals that of 
Vol/vox globator, and of other Infusoria ; and is probably without 
analogy among plants, (with which I reckon Pediastrum.) See 
observations of Weiss on Chlorogonium euchlorum, p. 192. 

Elu-enberg has named this genus Miorasterias, who characterizes 
it thus — by their members being free, by their having a simple 
compressed lorica, composed of one piece, and grouping themselves 
together in definite numbers, in the fonn of a flattened star. The 
latter generic character arises from incomplete self-division when 
they are young, like Gonium. Projection organs of locomotion 
have not been observed, though slow change of place has been 
noticed. Numerous vesicles, analogous to polygastric digestive cells, 
are seen in several species; ova-like green granules are abundant; 
and Ehi'cnberg states he has seen glandular bodies which periodically 
increase in size, and ai*e analogous to the seminal glands of other 
Infusoria. The dispersion of the ova has been seen by Tui-pin and 
Meyen, though it was regarded by them as that of the fecundating 
matter of plants. Dr. E. appends the following observations to the 
genus : — 

"1. The relations of number observed in Micrasterias appear to 
form a tii-m character of the species (as in Gonium pectoralc.) 



DesmiJiea.] infusokial animalcules. 287 

" 2. Tlio relations of size are not always in ratio witli those of 
number; for we find small size with a large number, and great size 
with a small number of parts. 

" 3. Fonns exhibiting equal relations of number to size, otherwise 
distinguish themselrea in secondary and less important points, as in 
a slender or thicker form of cell, long or short horns, &c., &c. ; con- 
ditions varjing in almost every individual. 

"4. Of the numerous forms seen by me, all were two-pointed, 
none had one-pointed bodies. (No Pediastrum simplex.) 

"5. llegularity of form is the character of integrity from ii-regu- 
larity; no distinct species can be formed." (P. 2. f. 114 to 117, 
121 to 123, and P. 13, figs. 22, 28, and 29, illustrate this genus.) 
Mr. Halts divides Pcdiadnmi into five sections. 

* Lobes of the outer cells emargmate or truncate. 

PjEDiASTKUir tetras = Micrasterias tetras, (Ehr.) — Cells four, se- 
parated by colourless interstices which form a cross ; lobes truncato- 
cmarginate. Frond extremely minute. Length of cell 1-294 1th. 
(P. 13. f. 27.) 

P. heptactis ^= Micrasterias heptactis (Ehr.) — Cells seven; six dis- 
posed in a circle around a central one ; cells bipartite, with emar- 
ginate lobes. Length of cell l-2906th. (P. 2. f. 114.) 

P. biradiatum = Micrasterias Rotula, (Ehi*.) Outer circle ge- 
nerally of eleven bipartite cells, with bifid or emarginate lobes. 

Var. (b.) — Lobes of outer cells ti'uncato-emarginate. 

The five-angular cells forming the inner circle are often quadri- 
lateral, and the exterior of each has a linear notch. Length of cell 
of outer circle 1 -2000th. 

* * Lobes of the segments entire. 
t Connecting substance coloured. 

P. Selenosa = Micrasterias Boryana (Ehr.) — Cells crescent- shaped, 
arranged in one or more circles, around one or two central ones ; 
connecting medium coloui-ed. Frond minute. 

1 1 Interstices of the frond hyaline. 

P. simplex. = Micrasterias coronula (Ehi-.) — Cells four, with or 
without one or two central ones; lobes of marginal cells ovate, 
tapering to a point. 

Var. {a.) — Marginal cells tnmcatc at the base and forming a circle, 
its centre vacant, or occupied by one or two cells. 



288 DESCEiPTiON OF [Poli/ffastrica. 

Var. (b.J cmciatum. — Cells angular at the base, connected in a 
crucifonn manner without a central space. 

Pediastkttm pertusum. = Micrasterias Boryana and M. trmjclia 
(Elu'.) — Inner cells leaving hyaline intervals resembling foramina; 
outer cells rectangular ; notch triangular, as broad as the cell. Frond of 
from one to three circles arranged round one or two central ones. 
The number of cells, as in P. Selenma and P. JBoryanum, generally 
consists of five in the first circle, ten in. the second, and fifteen in 
the third ; but Mr. Ralfs has seen fronds with four cells, forming a 
circle aroxmd two central ones. 

P. granulatum. — Cells granulated ; lobes of marginal cells tapering 
Frond of six cells arranged around two central sub-quadrate ones. 

P Jsapoleonis. ^^Micrasterias Napoleonis (Ehr.) — Six angoilar 
cell-;, foiming a circle around two central ones ; lobes of marginal 
cells arspidate ; notch wide. If not a variety of P. Boryanum ? 
(P. 2. f. 117, 118.) 

p. angulosum, = Micrasterias angnhsa (Ehi\) — Marginal cells with 
angular lobes, which are not extended into rays ; interstices hyaline. 
Frond minute, of one or more cu'cles around a single central one. 
The inner cells are angular, as in P. Boryana and P. eUipticum, but the 
marginal are less deeply notched, and the lobes nearly angular, not 
in the least extended into processes or rays. 

P. Boryanum. = Micrasterias Boryana (Elii'.) — Cells in one or more 
circles aroimd one or two central ones ; marginal cells gradually 
tapering into two long subulate points; notch narrow. (P. 2. 
f. 115, 116.) 

It differs from P. ellipticmn, in the gradually tapering acute lobes of 
the outer ccUs; from P. angidosKm in. itsloheshemg elongated as rays. 
P. cUi^iticmn = Micrasterias elliptica (Ehr.) — Cells variable in 
number and arrangement ; lobes of marginal ones suddenly con- 
tracted into short, cyhndrical, obtuse processes. Frond large. 
Yar. {h.) — Processes of the lobes truncato-emarginate. 
P. senaria (Ehr.) — Cells in two concentric circles around one in 
the centi'e ; twelve cells in the outer and six in the inner circle. 
External cells without appendages. 

The two folio-wing new genera by M. Corda, are here introduced, as 
they appear allied to Mr. Palfs genus Pediastrum. 

Cenus AsTEiiODiCTYON (Corda.) — Compound ; made up of many, but 



Desmidiece.'] ixfusobial animalcules. 289 

yet a definite number of corpuscles cells, forming a memhranoiis poly- 
pary (compound frond.) The frond is flat, stellate, multi-locvilar, and 
reticulate ; and each of its corpuscles has its margin extended into a 
tubular and pcr^'ious horn. Asterodidyon has a general resemblance 
to Monactinus and Pediastrum. 

AsTEEODicTTON- frianguhtm. — The smooth ti'iangular corpuscles are 
combined in triple series, and fomi a stellate disc. This compound 
star has its centi-e void, with an innermost row of five, a middle of 
ten, and a marginal of fifteen to sixteen cells. Diameter of each 
frustule l-1080th. ; of the entii-e star l-216th. JS'ear Berlin. 

A. ovatum. — Corpuscles granular, ovate, terminated by a long 
style, and ari'anged in two concentric circles, forming a star : three 
cells form the inner row, and ten the outer. Diameter of each 
l-780th., of the entire star 1 -312th. ; near Berlin. These forms, when 
sometimes irregular by monstrosity, very closely resemble the Monac- 
tinus simplex and M. acutangulus, of Corda. 

Genus Moj^Acri]ST:s. — Compound ; corpuscles numerous, connected 
so as to form a membranous polypary (frond) flat, stellate, multilo- 
cular, not reticulate, and having its cells in a single circle. Each 
cell tenninated by a solitary style (with a single aperture.) 

Pediastrum, which most nearly resembles it, differs in its forked 
or bidentate cells (and in its double aperture.) Ehi-enberg believing 
in the animal nature of the Desmidiece, the apertiu'es are important 
to his view. 

M. simplex (Corda.) 

MoxACTrNTJs acutangulus (Corda.) 

Genus ScEiTEDESjnjs (Ralfs.) — Frond composed of two to ten frisi- 
form or oblong cells, an'anged side by side in a single row, but after 
division in two alternating rows ; division obKque. Cells entire ; 
in some species the outer ones are lunate. There is no constriction or 
sutxu'e at the middle, and the endochrome is not divided into two 
portions by a transverse band. The division of the cells is oblique, 
and not ti'ansverse, as in most genera of the Desmidiece and as they 
all divide simultaneously, two rows are produced, which are held in 
opposition some time after division is complete, by the connecting 
hyaline matrix. 

The endochrome is, in general, very pale, and the starch granules 



290 DESCEIPTION OF [Pol^gasirica. 

are inconspicuous. Sccnedesmus differs from the preceding genera in 
the very different forra of its cells, but Fediastrum supplies a con- 
necting link between them. As in that genus, the fi-ond in Sccne- 
desmus is composed of several cells, but these are differently arranged ; 
and the division into two segments, which, although modified, is 
still met with in the outer cells of Fediastrum, is entirely absent in 
Scenedesmus. In the oblique manner in which its cells divide, it 
agrees with Sjpirotamia, which, however, has a different arrangement 
of the endochrome, and a frond consisting merely of a single cell. 

Scenedesmus quadricauda ^^ Arthrodestnus quadricaudatus (Ehr.) 
—Cells, generally four, oblong, rounded at their ends, disposed in a 
single row ; each extremity of the two external ones usually ter- 
minated by a bristle (P. 13, f. 19 and 36.) 

Var. fh.j — External cells with three bristles. 

Var. fcj ecornis = Arfhrodesmus ecornis (Ehr.) — All the cells 
similar and without bristles. Length of cell 1-1 12 1st. Breadth 
l-2631st. 

S. dimorjpJms := Arthrodesmus pectinatus (Ehr.) — Cells acute, four 
to eight placed evenly in a single row ; the inner cells fusiform, the 
outer externally lunate. Frond very minute. Length of cell l-1026th 
to l-906th. Breadth l-8160th. 

S. acutus = ArtJwodesmus acutus (Ehr.) — Cells two to eight, fusi- 
form, acuminate, arranged in a single, irregularly alternating scries. 
The two outer cells are frequently crescent-shaped. Length of cell 
1-1 063rd to l-1020th. 

S. oUiquus. — Cells eight, elliptic -fusiform ; after division arranged 
in two distinct, generally oblique series, the outermost cell of each 
not in contact with any of those in the other series. 

S. ohtusus. — Cells three to eight, ovate or oblong, and arrf Dgel in 
one row, or, after division, alternately in two rows. Frond minute. 
Endochrome very pale green. 

This species is rarely met with in a simple state, but, as the cells 
after division are retained in connection by the mucous matrix, two 
rows are usually present, the broader ends of one row lying between 
the cells of the other. The hyaline matrix is fr-equently their only 
bond of union, and in this state they seem to connect the Desmidiece 
with the TJlvacccn, through Merismopedia. 



Destnidiecs.} infusorial animalcules. 291 

ScENEDESMUS duplcx. — Cclls slciulci', fusiform, sigmoid, tapering at 
each end into a fine point ; after division, closely connected for 
about half their length. 

S. antemiatus. — Cells fusiform, somewhat ventricose at the middle; 
ends cuspidate, each terminated by a minute orbicular globule. 

The description of these genera, and some others since estabhshed 
by Ehrenberg, as also that author's characters of Odontella, wiU con- 
clude this section. 

Genus Sphaerasteitm. The round star Animalcules are characterized 
by theii" members being free, having a simple univalved smooth and 
turgid lorica, and by forming, during self- division, different shaped 
groups. A slight change of place or locomotion has been observed, 
but little or nothing of their organization is knoAvn, though Bory and 
Turpin have stated the existence of male seminal glands in S. 
quadrij\(ga. 

S. pidum has oval green corpuscles, passing into spherical clusters, 
of the form of a mulberry. Size of berry l-480tli; of single 
member l-1920th. Found with Micrasterias. 

S. qiiadrijugum has oblong green corpuscles, four being united into 
cubical mass, perforated at the middle. Size of berry l-570th; of 
single member 1-1 200th. Found with the former species. 

Genus Microtheca. The spinous disc Animalcules. It contains only 
one species, and is characterized by being free, and possessing a 
simple square compressed lorica, composed of one piece. In its 
organization it approaches that of GaUio?iella and Achnanthes. 

This genus is a very doubtful member of the Besmidiece. It 
presents no indication of the characteristic division into two valves ; 
and the golden colour of its only species, is a character of Diaiomece, 
and, consequently, an argtiment against its being one of the 
Desmidiece. 

M. octoceros has a square transparent lorica, with spines, 
(P. 2, f. 119, 120, the first a front, the latter a side view.) It is of a 
golden colom-, variegated ; change of place has not been observed. 
" I received," says Ehi-enberg, "in September, 1832, phosphores- 
cent sea-water, from the harbour of Kiel. On the 23rd of October 
I found therein this yeUow creature, which appeared very similar to 



292 DESCBIPTION OF {Polygastrica. 

a specimen of Anuraa, wliicli, together with yellow i)hopphore8cent 
species of Peridinea, were li\'ing in the same water ; but no direct 
evolution of light was observed from M. octoccros." Size l-280tLi 
without the spines ; with the spines 1-2 10th. 

Genus LiTHODESMruM. — Lorica simple, univalved, siliceous, and 
triangular in shape. Self-division imperfect, the creatures being 
clustered in the form of straight and rigid triangular-shaped wands ; 
cluster unattached. 

This genus was named and described by Elirenberg, in 1840, as 
belonging to the family Besmidiece ; however, this alliance would, 
from the illustration given, appear very doubtful. 

L. undulatiim. — Coi-puscles large, smooth, and pellucid; the angles 
obtuse. Two of the sides are undulated, the others doubly excised; 
openings and motion are not perceptible. The corpuscles are some- 
what longer than they are broad. Found alive, in sea- water, at 
Cuxhaven. Greatest length of corpuscle, l-480th. (P, 13. f. 
41, 42.) 

Genus Exjcampia. — Lorica univalved, wedge-shaped, and flat, 
excised in the middle of its lateral surfaces. Self-division being 
imperfect, the creatures are clustered in the form of flat articulated 
chains, having roimdish holes between adjoining segments, the 
cui'ved chains gradually becoming circvQar ; cluster unattached. This 
is another questionable genus of Desmtdiacea, described by Ehrenberg 
in 1840. 

E. zodiaca. — Lorica ciystalline, smooth, a little longer than it is 
broad ; ova of a light yellow colour. Locomotion not perceptible. 
Found alive in sea water, at Cuxhaven. Diameter 1-1 150th. 
(P. 13. f. 43.) 

Genus Odontella (Ehr.) — The tooth-cliainedAnitnalcuhs comprised 
in this small genus are unattached and free, having a simple uni- 
valved compressed lorica, and multiply by an incomplete spontaneous 
self-division, in the form of flat articulated ribbons or chains ; each 
link of such chain-like bodies is composed of a single pair united, 
which are connected with the next pair by two processes, a small 
space being left between them (see f. 108), and hence they difier 
from the genus Desmidium. The internal coloui'ed gi-anular matter is 



Besmdieie.] infusorial animalcitles. 293 

probably ova, and the three vesicles in 0. filiformis, stomach cells 
and fecundating glands. In 0. unidendata, the glandular body is 
very distinct from the digestive sacs. (See OdonteUa in next section.) 
Odontella desmidium. — Space between the processes of each pair 
distinct, (see f. 108.) Size l-1150th. to l-570th. (See page 242.) 
0. (?) filiformis. — The two slender processes connecting each pair 
leave a square space between them. (f. 107. See page 243.) 

0. unidentata. — Oval binary coi-puscles, often ii-rcgular ; they are 
connected by a single process in the middle. (See page 243.) 

Genus Gymxoztga (Ehr.) — Generic characters assigned to it by 
Ehrenberg, unknown. 

G. moniliformis. — Corpuscles ovate, concatenate, forming a filament, 
furnished with a median sulcus like that of GallioneJla, with a soft, 
not siliceous integument ; and, after the manner of the Conjugate, 
two corpuscles coalescing and producing another individual by their 
zygosis, or conjugation. Diameter 1-1 150th. Common in the marshes 
of Berlin. (\T.de DidymopriumBorreri.) 

Genus Poltsolenia (Ehr.) — Generic characters unknown. 
P. c/os^criK»«.— Corpuscles very largo, obtusely fusiform, straight 
or slightly lunate; thick, green, and smooth; at a later period 
hyaline cirrhose on every side. Length l-60th. to l-48th. Berlin. 

Has the habit of Closterium acerostim, whose structure it entii'ely 
resembles, except that, at certain periods, very many (to the number 
of fifty) cirrhi shoot out from as many apertures, not before visible, and 
seem to withdraw, in their exit, the internal green mass. 

This account appears like a misconception of some phenomenon, 
such as the germination of a spore, or the growth of mycelium on a 
Closterium, according to Mr. Ralfs it is = Penium digitus. 

Genus ZYsoxANTHruM (Ehr.) — Generic description wanting. 
Ehrenberg has most probably instituted Zggoxanthium as a sub-genus 
oi ^antliidium . 

Z. echinus "^ Xanthidium echinus, 1839. — Corpuscles (segments, 
Ralfs) globose, single and in pairs, aculeate, aculei thick, short, 
forked at the apex, or trifid ; and provided on the sides with two 
median tubules, having a stellate orifice : contents (ovaria Ehr.) 
green. Diameter of a single corpuscle 1 -480th. Internal granules 



294 DESCBIPTION OF [Polyfiastrica, 

often seem in motion. Two corpuscles unite by Zygosis {i. e. 
conjugate) and produce, between them, a smooth, globose young one. 
Genus TKirLOCEHAS (Bailey.) — Frond binate; segments straight, 
much elongated, with numerous whorls of knot-like projections ; 
ends of the segments threc-lobcd ; lobes bidentate. A genus closely 
allied to Bocidium, differing in the three-parted ends of the seg- 
ments. 

T. verticillatum (Bailey) = Bocidium verticillatimi (Ralfs.) 

T. Gracile (Bailey.) — Slender, with whorls of rounded projections. 



SECTIOIf II. — Navicflacea.. 

This section, together with the Echinellea, and the Lacernata of 
Ehrenberg, are equivalent to the Biatomacea, Biatomece, or CymieUece, 
of other authors. In the following observations on structure, habit, 
&c., it is proposed to comprehend all the forms of Bacillaria, exclusive 
of the Bcsmidiacea. 

The individuals of tlie Biatomea are variously spoken of as testules 
{tesfnld') or frnstiiles; and also, when forming members of a compound 
band, chain, or filament, or of other aggregated mass, as — segments, 
coi-puscles, and sometimes loricse. But the term lorica, though often 
used as equivalent with frustule, rightly expresses merely the 
exterior coat, or shell which determines the form of the individual, 
and is in this section always siliceous. 

This lorica, in its multiplied and often veiy beautiful forms, con- 
sist sof an outer clear or hyaline, colourless, siliceous coat, and of an 
inner more or less coloured one, considered to be of a softer and 
more organic constitution. Nagcli supposes a mucilaginous film to 
exist on the inside of this second coat : and Klitzing also speaks of 
a third element, displayed when recent frustules are dried, and 
especially after their having been heated to redness, as an opaque or 
brownish space, extending itself, not unfrequently, over a considerable 
portion of the lorica. To this material the name of cement is applied 
by Klitzing, as he supposes it to be the connecting material of the 
valves or portions of the lorica, and also of frustules when united. 



Naoiculacea.] infusorial animalcules. 205 

Its bro^\^l coloiu' he would attribute to the probable presence of 
iron in its chemical composition. 

Two views have been advanced relative to the origin of the ex- 
ternal siliceous lamina ; one, that the silex exists in intimate union 
with the cell, whose wall is believed to consist of cellulose pcneti-ated 
with silica ; the other, that the siliceous valves are deposited 
exterior to a cell-membrane. (Smith, Ann. Nat. Hist. 1851.) Nageli 
says, " This es outside the membrane, and must be regarded, from 
analogy to all other similar structures, as extra cellular substance 
excreted from the cell" (Eay Society, 1846, p. 220.) But apart fi'om 
analogy, Mr. Smith states he has direct evidence of the independence 
of the siliceous coat, having in his possession numerous specimens of 
A. Stauroneis (probably of S. asiyera, Kiitz.), in which the valves, 
after a slight maceration of the frustulcs in acid, have, in part or 
Avholly, become detached from the cell-membrane, leaving a scar on 
its walls, bearing the distinct impression of the numerous and pro- 
minent valvular marking of this beautiful species." StiU more 
recentlj'. Prof. Bailey, of New York, states, that if hydrofluoric 
acid is ajjplied to recent, or even sometimes to fossil JDiatomacea, the 
sheU soon dissolves, leaving distinct internal, flexible cell membranes, 
retaining the general foim of the shells. 

This second view of the separate existence of the inorganic sili- 
ceous tunic, and its origin fi'om the organic internal membrane, 
appears therefore the true one, from the preceding facts, and it is 
still further supported by the phenomena of self-di-s-ision of the 
fnistules; for in this process the lining cell-membrane takes the 
initiative, and is followed by the doubling of the external coat upon 
it, as an after production. 

Ehrenberg states the lorica to be composed of two or more pieces 
or valves; Mr. Ealfs saj's, "it consists of three pieces, one central 
and ring-like, or continuous all round, and the other lateral;" but 
the investigations of the Eev. W. Smith would go to prove, that, in 
not a few instances, the central ring-like segment is not an essential 
one, but only developed when self-division is proceeding. In some 
of the anomalous genera of Ehi-enberg, as jDictijocha, the individual 
would seem to be composed of several pieces, varying in number in 
various species. 



206 DESCRIPTION OF [Polygastrica, 

The siliceous external coat is often very beautifully sculptured; 
the markings being modelled on the living organic membrane. Much 
discussion has arisen as to the true nature of these markings, which 
assume the appearance of dots fpunctaj, ribs fcostce), stria?, pinnules 
(pinnae), furrows, or lines — whether the dots are actually pores, as 
generally surmised by Ehrenberg, and whether the ribs, stria3, or 
lines, are depressions or elevations of the surface, or even sometimes 
figures. The opinion seems to be gaining ground, that the lorica 
is entire without pores or fissures ; in favour of this opinion, are 
Balfs, Nageli, Dujardin, the Eev. W. Smith, and Schleiden. On the 
contrary, Klitzing supposes the gelatinous investment of many 
Diatomece to issue from pores in the lorica ; and Ehrenberg believes 
in the existence of both pores and fissures, supposing the former to 
give exit to organs of locomotion and the latter to ova, &c. (See 
genus Navicula, and plates 19 and 20.) In several genera, for 
example, SJiqjodiscus, Cemtaulus, Rhizoselenia, &c., the lorica produces 
more or less extended processes, simple or branched (ramose), which 
are generally known as cornua, sometimes as tuhuU (Ehr.) It often 
happens that the apparent lines, or bands, on the surface, are merely 
indications of internal partitions (septa), and which are either com- 
plete or perfect (/. e., entirely dividing the internal cavity of the 
lorica), or incomplete (imperfect.) To the partial septa, as ia Gram- 
matophora, Kiitzing has assigned the term viU(2. " The lines," 
says Niigeh, speaking of a form allied to GalUonella (Elu-.) "which 
would intimate a division of the shield into two or more pieces, are 
the septa by wliich the cell-division is effected." 

The puncta, costa), and other external markings, as also the 
processes of the lorica, are valuable in forming specific and generic 
characters. The presence or absence of a ccnti'al pore often forms a 
leading characteristic. Kiitzing, indeed, rests his great division of 
the BiatomecB into StomaticcB and AsfomaticcB, on this peculiarity. 

The distinctness of the various markings of the lorica is much 
interfered with by the presence of the lining membrane, which should 
therefore be destroyed by maceration in nitric acid, or by exposui-e to a 
strong heat. 

The cavity of the lorica, in the true Biatomacece, is now generally 
admitted to be single ; in other words, their frustules are uni-cellular. 



Kaviculacea.] infusobial animalcttles. 297 

In the Navicuke, Schlcidcn believes he has proved this by direct 
observation. Mr. Ralfs, indeed, states, that, in JVavicuIa and other 
genera of Biatomaceee, the frustnles are often truly binate, but wo 
question whether they are actually so, except when fission is pro- 
ceeding. Throughout his learned essay on the cell-nucleus and 
cell-formation, Niigeli treats of the Liatomacea as uni-ccllular 
organisms. 

Each frustule generally presents four sides, or planes, which, un- 
fortunately, have been variously designated. Ehrenbcrg has used the 
terms dorsum, venter, and lateral surfaces or sides, but which do not 
in all instances represent homologous surfaces. Oftentimes he has 
called a convex surface, simply on account of its convexity, the 
dorsum ; and a concave one, from its concavity merely, the venter, or 
ventral surface. 

Kiitzing has endeavoured to amend this nomenclature, by calling 
those sides which have no central opening, but through which self- 
division occurs, the primary sides ; and the other two, the secondary 
sides. These secondary sides are further distinguished into right and 
left, when the frustule lies on a primary side. The left is often 
concave, and the right convex, but mostly the two are alike. As a 
general inile, the primary sides con^cspond with the so-called lateral 
surfaces of Ehi-enberg, and the secondary sides, respectively, with the 
dorsum and venter of that author. 

The Kev. "W. Smith has the following remarks on this subject, 
which illustrate the usage of most English ^Titers: " Late wiitera 
have found, in the process of self-division, circumstances to fix the 
terminology applied to the Diatomaceous fr'ustules, and use the words 
'primary sides,' when speaking of those portions where the inter- 
position of the new haK-frustules occurs; the term secondary sides 
being applied to the general surface of the valves ; others employ the 
words front and lateral view in the corresponding senses. I shall 
adopt the latter terms as more generally applicable; the primary 
side, as employed by the writers alluded to, frequently including 
portions of the frustule which belong to the secondary surfaces, brought 

into view by the convexity of the valves With Mr. Ealfs, 

and other English writers, I would use the tQvm. front view to denote 
the aspect of the frustulcs, Avhen the connecting membrane and 

X 



298 DESCBIPTION OF {Polygcistrica 

valvular suture are turned towards the observer; the words lateral 
or side-view, when the general sui-facc of one of the valves is 
directed to the eye." 

When any two opposite surfaces approximate about the margin of 
a frastule, the other two sides are reduced to so narrow a band as to be 
vii'tually obliterated, and are then spoken of as obsolete. 

"Within the lorica is contained the living substance of the frustule, 
regarded by Ehrenberg as fonning definite animal organs, viz., 
stomachs, ovaries, and ova, semiaal glands and vesicles. But all such 
animal organs are ignored by other naturalists; and the contents 
generally are known as the endochrome, whilst the particular vesicles 
and granules are represented as similar to the like formations in the 
Confeiwae, and as constituted of chlorophyll, starch, and mucilage. 
The number and position of these vesicles vary in individuals of the 
same species ; sometimes, indeed, specimens occur with no vesicles 
(stomach-sacs of Ehrenberg) ; and further, a circulation or rotation of 
the contents of the cell has been observed by I^iigeli in a Gallionella, 
and by Rev. W. Smith in Surirella. Some of the clear vesicles, 
Kiitzing has concluded to be oil particles; and affirms, that he has 
occasionally seen two coalesce, proving the absence of proper walls. 
The entire endochrome that author also has designated the gonimic 
substance. 

The prevailing colour of the endochrome of DiatomecB is golden- 
yellow or brownish ; very rarely gi-ecn, except when the frustules 
arc ch'ied. 

According to the researches of Niigeli, the Diatomece present, gene- 
rally, among their other contents, a nuelem, which in some genera is 
free (isolated) within the general cavity, or parietal — affi-sed to the 
walls, as happens in GallioneTla. This special organ plays a veiy 
important part in the phenomena of cell growth, and, in the opinion 
of Schleiden, precedes and brings about the formation of the cell -wall 
enclosing it. Niigeli makes two sorts of nuclei, primarij and 
secondary, attributing to the former the same properties as does 
Schleiden in the original formation of the cell, and in its subsequent 
multiplication by self-division. In the latter process, the nucleus is 
supposed first to double itself, and then the septum to appear, which 
ultimately halves the frustules. 



Navtculacea,] infusorial animalcules. 299 

Kdgcli further describes the cell formation in BiatomacecB, as 
taking place around the whole contents of the parent cell: that 
" diii-ing the production of the septum, the secretion of gelatinous 
matter continues over the whole surface of the cell contents. The 
production of the septum itself may be thus explained : the contents 
separate into two parts, each becoming invested with a membrane, 
which appears as a thin wall between them, but is actually com- 
posed of two lamellae." 

Oiu' space, and the nature of the treatise, forbid entering more 
largely on this interesting but much vexed question of the nuclear 
development of cells. Those readers who desire to follow up the 
subject, cannot do better than study the learned disquisition by 
Niigeli on cell-formation, quoted in the preceding pages. 

The Rev. W. Smith has given the following succinct account of 
the process of fissiparous, or self-division: "At first, the siliceous 
valves (as seen in front view) are in close contact at their suture 
(P. 18, f. 20), but their adherence is speedily disturbed by the 
dividing process which these minute organisms are constantly under- 
going. The first step in this process is the gradual separation of the 
valves, an efiect apparently produced by the expansion of the internal 
membrane. Pari passu with the retrocession of the valves, the cell 
wall exposed between their edges is being covered with a deposit of 
silex, and the frustule now consists of two symmetrical valves, 
united by a plate of silex (P. 18, f. 23) which either forms a con- 
tinuous ring (P. 18, f. 22) or consists of two portions united at the 
extremities of the valves. This plate, with the underlying cell- wall, 
may, for the sake of distinctness and future reference, be termed the 
connecting membrane. 

" When the connecting-membrane has been fonned of sufficient 
width, the original cell, i)robably by the doubling in of its wall, 
becomes divided into two, and immediately secretes, at the line of 
division, two new siliceous valves, symmetrical with, and closely 
applied by their edges to the original halves, and thus the self- 
division is complete, and two perfect frustulcs have been the result, 
(P. 18, f. 20.) 

" In some cases, by the new or rather scrni-new frustulas imme- 
diately proceeding to repeat the process, the connecting-membrane is 
X 2 



300 DESCRIPTION OF \Vi)lijgasirica 

thrown off and disappears ; in othei's, it reuiaius for sonic time 
linking the frustulcs in pairs, as in Mdosira and Odontclla ; and 
sometimes it is only partially torn away or absorbed, and unites the 
fi'ustules successively formed in a zig-zag chain, by portions re- 
maining attached to their angles, examples of which we find in 
Biatoma, Isthnia, &c. (Ann. Nat. Hist. 1851 p. 4.) 

" There appears, however," says Mr. Thwaitcs, *' a limit to this 
mode of propagation of the finistule, except by the intcr-s-ention of 
another phenomenon — viz., conjugation, or a mixture of endo- 
chromcs; after which process, fissiparous division proceeds as before." 
(Ann. Nat. Hist. 1848, p. 161.) 

Moreover, self-division is an act only of muUvplicaUor>i physiologi- 
cally speaking, for all the fnistules so produced, are but parts of the 
original individual producing them, — of that one which derived its 
individuality from a sporangium, the result of conjugation, which 
is a process of actual propagation. 

The elucidation of this w^onderful phenomenon of conjugation in 
the Diatomacem, we owe* to Mr. Thwaites ; from whose papers we 
shall endeavour to give a condensed account of it. 

For the most part, conjugation in the Diatomacea, as in the 
Desmidiem, consists in the union of the endochrome of two approxi- 
mated fronds, this mixed endochrome developing around itself a 
proper membrane, and thus becoming converted into the sporangium. 
In a very early stage of the process, the conjugated frustules, as in 
JEunotia turgida, have their concave surfaces in nearly close apposi- 
tion (P. 14, f. 1) and from each of these surfaces two protuberances 
arise, which meet two similar ones in the opposite frnstule (P. 14, 
f. 3) ; these protuberances indicate the future channels of com- 
munication by which the endochrome of the two fnistules becomes 
united, as wx^ll as the spot where is subsequently developed the 
double sporangium, or rather the two sporangia. A front view of 
two frustules at the same period, shows each of these to have 
divided longitudinally into two halves (P. 14, f. 4.), which, though 
some distance apart, are still held together by a very delicate mem- 
brane ; that, however, soon disappears. 

The mixed endochrome occurs, at first, as two irregular masses 
between the connected frustules, but these masses shortly become 



Naviculacea.'] infusorial animalcules. 301 

covered, each with a smooth, cylindrical membrauc — the young 
sporangia, which gradually increase in length (P. 14, f. 5, 6) retain- 
ing nearly a cyKndrical form (P. 14, f. 7) until they far exceed in 
dimension the parent frustules, and, at length, when mature, become, 
like them, transversally striated upon the surface (P. 14, f. 8.) 
Around the whole structure a considerable quantity of mucus has, 
during this time, been developed, by which the empty frustules are 
held attached to the sporangia (P. 14, f. 5 to 8.) 

In the immature condition, it happens that the sporangia, in many 
species, resemble in general characters the mature frustules of 
another species, or even of an allied genus. Thus the sporangia of 
Gomphonema minutissimum, and of G. dichotomum, have a close re- 
semblance to frustules of Cocconema. On tjie other hand, in some 
genera, as in Cocconema, the sporangia take on at once the exact 
characters of the ordinary fi'ustules, from which they differ only in 
their exceeding that of the majority of the latter in dimensions. 

When a sporangium in a ti'ansitional condition is like the frustule 
of another genus, we are assisted in. distinguishing its true nature 
and affinity, oftentimes by the persistence of the mucus diffused 
around it ; or, by continued observation, we may witness its 
assumption ultimately of its true specific characters, including the 
development of its pedicle or stalk, where the possession of such an 
organ is a characteristic (as in Gomphonema.) The development of 
the sporangium being complete, it enters on an independent existence, 
which it displays by undergoing fissiparous division, as in common 
frustules. 

It is veiy probable that transitional forms have been described as 
particular species, or located in wrong genera. Thus, Mr. Thwaites 
thinks that Kiitzing's £pithemia Vertagas is the sporangium of 
Eunotia targkla. 

In different genera, slight variations are met with in the method 
of conjugation : thus, in some species of Gomphoyiema the sporangia 
lie in a du'cction parallel to the empty frustules, instead of across 
them, as described in Eunotia turgida. Again, there are examples (in 
Gomphonema minutissimum and Fragilaria pectinalis), where, instead of 
the conjugated frustules separating into two halves, only a slit 
appears at one end, to serve for the escape of the endochrome. 



302 DESCRIPTION OP [^foli/gastrica. 

Instead; also, of the pair of conjugated frastules producing between 
them two sporangia, they may develope but a single one, as happens 
in Fragilaria pedinalis. In this species, too, the sporangium, at first 
cylindi'ical, soon assumes a flattened, somewhat quadrangular form, 
and, in many cases, undergoes fissiparous division before it has put on 
the exact appearance of the fmstule of a Fragilaria. 

"The Ifeloseiree {Gallionella, Ehi\), and the Bid(lulphi<^, (Mr. 
Thwaites remarks), would seem, in their development of sporangia, to 
offer an exception to most BiatomacecB ; for in those genera no 
evident conjugation has been seen. However, something analogous 
to it must take place; for, excepting the mixture of endochromes of 
two cells, the phenomena are of precisely similar character. Thus, 
instead of the conjugation of two frustules, a change takes place in 
the endochrome of a single frustule, — that is, a disturbance of its 
previous arrangement, a mo\T.ng towards the centre of the frustule, 
and a rapid increase in its quantity : subsequently to this, it becomes 
a sporangium, and out of this are developed sporangial frustules, as 
in the other Biatomacece. In a single cell, therefore, a process, 
physiologically precisely similar to that occurring between two con- 
jugating cells, takes place ; and it is not difficult to believe, taking 
into view the secondary character of cell-membrane, that the two 
kinds of endochrome may be developed at the opposite ends of one 
frustule, as easily as in two contiguous frustules, and give rise to the 
same phenomena as ordinary conjugation." In the Zygnemece, 
adjoining cells in the same filament are found to conjugate. 

The process of conjugation has now been seen in most genera of the 
well-defined Diatomacem. Observed first in Eunotia, it was sub- 
sequently seen in Gomphonema, Cocconema, Fragilaria, Schizonema, 
and its modified character in Melosira and Biddulphia. 

Kiitzing, unacquainted, at the time his treatise was written, of 
propagation by conjugation, considered that the Biaiomem multiply 
in three ways: — 1. By development of their gonimic substance 
(endochrome) which, as he says, happens in the lower Algae, but in 
the Biatomea is uncertain. 2. By fission, complete, or incomplete, 
a ge.ieral mode; and 3. By gemma) or spores, the formation of 
which he has vv'itnessed in several si^ecics of Melosira, in Schizonema, 
and in Mivrome^a, 



Naoiculaeea.] infusorial animalcules. 303 

Ai'c the Diatomacea plants or animals? is still a questio vexata. 
The able discussion of this point by Meyen, in the case of the 
Bac'dlaria, generally, is given in the previous pages ; and here ia 
appended a summary, by Kiitzing, of th.e arguments urged on each 
side in the case of the Diatomem. 

" For their animal nature, Elircnberg presents the following 
arguments. 

1. The Diatomca exhibit, in part, a peculiar spontaneous move- 
ment, wliich is produced by certain locomotive organs. 

2. The greater part have in the middle of the lateral surface an 
opening, about which round corpuscles are situate, which become 
coloui'ed blue when placed in water containing indigo, like as do the 
stomach-cells of many Infusoria, and, consequently, they may also be 
regarded as stomachs. 

3. The shells of many Diatomacecs resemble, in structure and con- 
formation, the calcareous shells of Gasteropoda, and similar Mollusca. 

Of ihe first argument, it may be observed, that spontaneous motion 
is met with also in the lower plants, in which, moreover, it arises from 
special ciliary locomotive appendages. I would instance the obser- 
vations of TJnger on Vaucheria cla/vata of Flotow on Hernato- 

coccus pluvialis, and lastly my own (in the Phycologia c]eyieralis) on 
Ulothrix zonata, and other Algae ; all which shew that in these lower 
organisms evident movements occur, not to be distinguished from those 
of the Infusoria. 

Hence this argimient fails. 

As to the second position ; the colouring of the so-called stomach- 
cells by indigo, as I have before proved, is probably but a mechanical 
operation ; and affords no evidence of their stomach-like character, 
and especially as the vesicles are often wanting. 

Of the third argument. The shell has frequently, indeed, in 
stnicture, conformation, and markings, a similarity to that of 
MoUusca, but this is not invariably the case, and we find among the 
cells of higher plants, those which, in configuration, form, and other 
particulars, exhibit similar aj)pcarances. For instance, the numerous 
forms of pollen, with their angles, spines, orifices, &c. In this matter, 
relation of form, therefore, the DiatomecB stand as closely to vegetable 
as to animal structures. 



304 DESCEiPTiON OF \^Poly gastric a. 

Ou the other hand, the following facts are in favonr of their 
vegetable natiu-e : — 

1 . The great resemblance of compound forms to Algae, and their 
develoj^ment by fission. There are, indeed, compound Infusoiiaj as 
Monad-masses and Polypes, but the former are very questionable 
animals, and the latter have this essential distinction, that the indi- 
vidual animal lives without (external to) its habitation, and moves 
freely ; whereas such Naviculce as Encyonema, ScJiizonema, and Mi- 
cr omega, and similar genera, grow within the enclosing substance, 
building themselves up like the cells in the stem of a plant, so 
vegetating here only as cells. In like manner, the individuals of 
Fragilaria, Mehsira, Himantidium, &c., are steadily fixed, and 
tuiable to exhibit animal motion. 

2. The inner soft, organic parts, which I have designated gonimic 
substance, possess, as well in their chemical nature as in their 
development, peculiarities akin to those met with in the cell-contents 
of confer void Algae. 

This relation is most clearly seen in the genus Mehsira and its 
allied forms, which, not only in form, but also in the chemical com- 
ponents of their contained matter (since the presence of chlorophyll 
is common to all Diatomece), are closely allied to the confervoid Algae. 

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

4. The Biato^necG, and especially the free, moving Nwviculce, 
developej in the sun's rays, an appreciable quantity of oxygen, like all 
admitted plants. 

The evolution of oxygen, indeed, occurs in gi-een Monads and 
Euglena, but this affords no argument for the animality of the 
Diatomece, but renders the animal nature of those Infusoria themselves 
veiy doubtful ; and the more so, as recent observations conifirm the 
idea of the origin of the lower plants themselves, from Monads and 
Ewjhna, (page 18.) Wherefore, aU these comparisons serve to 
favour the belief in the vegetable nature of Diatomece, (Diekiesels- 
chaligen, Bacillarien odcr Diatomeae, Von Dr. F. T. Kiitzing, 
Nordhausen, 1844.) Some English writers have acceded to the 
opinion that tlie Diatomm arc vegetables, from the above views 



Naviculcieca.] INFrSOEIAL ANIMALCULES. 303 

expressed by Kiitzing, and, above all, from the plienomenon of con- 
jugation. This last, so much insisted on as a proof of their vegetable 
natui-e, has been already dwelt upon in this volume. 

M. Thuret, in his late essay, expresses himself to the effect that 
there is no more reason in the favour of the one view than of the 
other. Schleiden, after describing the siliceous lorica, adds : " Such 
an artificial and complicated structiu'e among plants has no explana- 
tion, and is entirely without signification. In all actual plants we 
find the silica present, in quite a different form, as little separate 
scales or drops, and distributed throughout the substance of the cell- 
wall." Professor Bailey's opinion is decidedly in favour of their 
being animals. (See page 217.) 

In a geological point of view, the members of this great section 
are the most important of organized beings ; for, although individu- 
ally invisible, they exist in such countless myriads, that they form 
strata of great extent, and play a far more important part in building 
up the earth's crust, than the gigantic Saurians of past ages. The 
town of Richmond, in the United States, is built upon a stratum 
twenty feet in thickness, composed almost entirely of the siliceous 
shells of the Naviculacea. This is not an isolated fact. In Bohemia, 
at Bilin and -lEgina, deposits of similar origin cover many miles of 
surface. In Sweden and other countries, shells of vai'ious genera 
abound. These organisms are found in the Pliocene, Miocene, 
Eocene, and chalk formations; indeed, even the Oolitic and older 
sti'ata are not without traces of them; hence, although occupying 
the lowest place in the animal series, they form an extended base of 
a triangle, on which man stands at the apex. (See geographical dis- 
tribution, Sec, page 62.) 

The study of these organisms in connexion with agriculture, has 
not been much attended to ; so much, however, has been ascertained, 
as to render its importance undoubted. In Guano manui-e, the 
presence of shells of Bacilla/ria is not thought to add to its fertilizing 
qualities, but Dr. Bailey has shown that the gTcat fertility of the 
rice fields of South Carolina is mainly due to them. 

Liatomacea arc very abundant, both in the sea and in brackish tmd 
fresh water ; some genera are essentially marine, others peculiarly of 
fresh water habit. 



306 DESCRIPTION OF [Puli/ffastrica 

In pure river or spring water these little beings are not found ; 
but on the banks of rivers and ditches, about the source of springs, 
and also in gutters and moist places generally, they are abundant. 

The fine fibrous Alga), marine and freshwater, are often richly 
clothed with them, sometimes indeed completely overgrown by them. 
They are common, too, in summer, in small ponds, and in the mud on 
the sides of ditches, and, when numerous, impart a brown colour. 
On warm summer days, they are often raised to the surface by the 
oxygen gas they generate, and which adheres to them, when they 
form thin, delicate films on the siu-face, and sometimes a layer of 
greater thickness, mucous and compact. Otherwise, they occur 
in aggregated, iatricate masses. The microscope shows the thin 
pollicle oftentimes made up of various species, mostly Naviculce, 
Oymlellm, Surirellce, or free Synedra, congregated together, and 
having a more or less lively motion. The mucous and larger masses, 
generally have but one prevailing species. 

The 3IehsircB {Gallionella, Ehr.) build brownish, conferva-like 
masses, which afiix themselves to plants, or stones, or other solid 
substances in the water; other forms, as Fragilaria, occur gene- 
rally on decaying wood or leaves, or amongst Conferva, mingled with 
Cymhellce, Synedra, &c. It seldom happens that one form is found 
alone. Larger specimens are mostly met with in aggregate, attached 
masses ; smaller when isolated, free and moving about. 

Brackish water, where a river discharges itself into the sea, or 
where the sea water rises with the tides and mixes -with the fresh 
water of the stream, are localities in which Naviculacea abound. 
Such water, on being passed through a filter, leaves aU its larger 
particles behind on the cloth, and these can be collected and prepared 
as may be required. AVhen we have to deal with a film on the 
surface, it may be removed with a spoon or spatula, and placed on 
paper ; where the frustules grow on Algse, the two may be removed 
together. 

In the case of fossil Diatomacea, which mostly occur mixed with 
various mineral particles, they may be separated for examination, 
as described in Part II. page 110. 

The following veiy ingenious plan of getting transverse or oblique 
sectiouB of the smaU lorica: of Xavuuh, and of other Diafomecc, is 



Naviculacca.'] infusouial animalcules. 307 

given by Schleiden, and is similar to the plan of making sections of 
hair for the microscope : " This may be done by taking some of the 
siliceous earth of Erbsdorff, and mixing it with mucilage, and, 
before it is perfectly hardened, cutting off delicate plates with a 
razor." (P. 18, f. 4) " exhibits a section of the upper part of a shield 
prepared iu this way." (Principles Botany, page 594.) 

Kiitzing offers the following arrangement of the Nmiculmea, or, 
as he calls them, Biatome(Z. He objects to the systems of other 
naturalists, stating "that they have all one leading error : viz., that 
of assuming as their basis characters extremely variable, and scarcely 
to be employed in the identification of individual species, — such as 
the presence or absence of a gelatinous indu\'ium, or of a stipes or 
pedicle ; or the occurrence of the frustules solitary or concatenated." 

On the other hand, the structure of the shells being constant, he 
has employed it in framing his an-angement, as follows : Tribe 1 . 
Striated BiatomecB ; lorica siliceous, and either quite smooth or 
transversely striated on the secondary side, but never vittate or 
areolate (cellular.) Tribe 2. vittate (striemigej ; lorica siliceous (on 
primary side) longitudinally (rarely transversely) vittate, smooth or 
transversely striated, but never areolate. Tribe 3. Areolate (^Zellige) 
Diatomea ; lorica siliceous, secondary side areolate or cellular. 



308 DESCBiPTioN OF [Po1ij(jastrica. 

The accompanying tabular view displays tlic further division into 
orders and families, by Kiitzing, of the Diatomea. 

* Transverse strife unbroken. 
Family 1. Eunotieoe 

2. MeridiesB 

3. Fragilarieaj 

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

e L 5. Surirellese 

a. MONOSTOMATIC-E j 

Family 6. Cocconeideae 
— — 7. AchnantheEB 

6. DiSTOMATICiB 



Order I, 

AstomaticaB 

Without a central < 
opening: on the 
secondary side. 



Order II. 
Stomatic£B 



Ilavins; a median aperture on only 
one of the two secondary surfaces. 



ri i 



With the central 
opening 



Order I. 

Astoniaticae 

Without median 
aperture on se- 
condary side. 

Order II. 

Stomatiene 

With a large dis- 
tinct one. 

Order I. 

Disciformes 



Order 

A])pcn(liculat;T?, -^ 
Appended and j 
doubtful forms. 



^ With a median aperture on each 
\ secondary surface. 



Family 8. Cymbellere 

9. Gomphoueraea; 

■ ■ 10. NaviculeuB 

1 1 . Liemophorea) 

■ 12. Striatellece 



13. TabcUaricaj 



{- 



— 14. Coscinodisccoe 

15. Angnliferas 

16. Tripodiscea) 

17. Biddulphicaj 

18. Angulatae 

19. ActiniscecB 



In a recent volume, entitled " Species Algarum," Kiitzing docs not 
give any tabular view of the Diatomea. 

The arrangement of the numerous genera which compose this 
section of the family Bacilluria, presents many difficulties. Althougli 
much has been done of late, yet much remains to be done before a 



JVaviculacea.] infusorial animalcules. 309 

permanent arrangement can be made according to their affinities. 
The improvements on the microscope have enabled us to discover 
markings on the shells previously considered smooth, hence new 
divisions are daily required. In the following pages the plan of the 
former edition will be continued, so far as to form them into three 
sub-sections, \iz., JS^aviculece, EchineUce and Lacernatm. In each of 
these the genera will be placed in. alphabetical order, but when a 
large genus has been divided, its members, or sub-genera, will be 
found with it. Eefcrcnce to the index will afford every facility 
required. (This section is illustrated by P. 2, 3, and 4, f. 127 to 208. 
P. 13, f. 45 to 50. P. 14 to 20 and 24, except a few figures in 
plates 14, 15 and 18.) 



Sub-section. — NAVICULE^ (Navicuiacea Liatomece.) — Lorica 
simple, unattached. 



Genus AcTiNocrcLrs. (Ehr.) — The rayed hox-lihe leings ; bivalve, 
disciform, or shortly cylindrical, cellular f reticulated j ; the cells 
interrupted by many smooth rays ; self-division imperfect, forming 
chains ; lorica Avith internal septa. Kiitzing, however, characterizes 
the members of the genus as solitary, and, moreover, as destitute of 
internal septa. 

Ehrenberg observes, that the cellular character of the lorica, dis- 
tinguishes Actinocyclus from Gallionella, although an approach to 
a like condition may be seen in Gallionella sulcata. 

Actinocyclus, Actinoptyclius, and Coscinodiscus, constitute Kvitzing's 
family Coscinodiscem. This family is most akin to Melosira f Gallionella, 
Ehr.) but differs by the cellular or reticulated surface of the discs. 
AH the genera are marine. 

A very large number of species of Actinocyclus have been created 
by Ehrenberg, the characteristics of which he derived from the 
number of rays, and where this failed, from the presence or ab- 
sence of septa. Of the latter plan, the distinction between 
A. bioctonarius and A. sedenarius is an example, the number of 
rays being alike in the two ; but the former is destitute of septa, 
which the latter possesses. More recently, Ehrenberg has created 



310 DESCRIPTION OF {Tolygastrico. 

the genus Actinoptychis, to contain all the species of Adinocychi, 
having internal septa: all such, therefore, should he excluded 
from the present genus. They are continued here on account of 
their having received their original appellation and position in this 
genus from Ehrenherg. It is therefore to he rememhered, that those 
species described as having internal septa, are now Actinoptychi, with 
the same specific names. 

AcTiNOCYCLTTs quatuordenarius, with fourteen rays, and as many in- 
ternal partitions, sub-dividing its area into distinct cells (loculi.) 
Diameter 1 -480th. Found in the North Sea. Cushaven. 

Of many remaining forms, it will suffice to indicate the number of 
radii, and the locality and dimensions. 

A. ternarius, with three rays. In chalk marl. 
A. quaternariiis, with four septa and rays. Same habit. Yirginia. 
Diameter 1 -552th. 

A. quinarius, with five rays ; same habit. Fossil in chalk marl 
of ^gina, &c. 

A. nonarius. — Septa absent; rays nine, finely punctated. Found 
both fossil and alive. The single discs of the fossil forms are 
generally without margin : they are sometimes quite perfect, but 
often in broken pieces. In the living creatures, the gi'anules 
are yellow; locomotion not observable. Diameter 1- 720th. to 
1 -650th. 

A. denarius. — With ten rays, fossil in the chalk marl of Oran ; 
and living in the waters of the Cattegat. 

A. U7ule}iarms. — Partitions not present, rays eleven, finely pimc- 
tated. Found alive and fossil. The discs of the fossil forms are 
destitute of margin, and are single, whilst those of the live creatures 
have a broad edge and are double. In those specimens in which the 
margin is absent, there exists as many roimd openings as there are 
punctated rays. Diam. 1 560th. to 1 -480th. 

A. hiscnan'us. — Septa absent, rays twelve, finely punctated. Found 
fossil and alive with the three preceding. The fossil fonns are 
sometimes smaller than those of the living, but mostly about equal. 
In the live condition, gi-anules are visible, as twenty-two greenish 
masses around the colourless spot in the ccnti'e of the body. NeitJior 
marginal openings nor locomotion have been satisfactorily seen. 



Naviculacea.'] infusorial animalcules. 311 

Diameter of fossil, as low as l-8G0th; of living, as high as 1 -580th. 
This species differs from A. duodenarius by the absence of septa. 

AcTiNOCTCLUS duodenariiis. — Disc divided internally, by partitions, 
into twelve cells, and having twelve finely punctated rays; six dark and 
six bright triangidar divisions are seen, in the centre of each of which 
rnns a narrow line, terminating at tlie margin in a little opening. 
The internal partitions appear to lie between every two of these 
narrow lines, so that as many as twenty-four rays may be counted, 
but there are only twelve openings visible. Diameter 1 -560th to 
1 -480th. 

A. quindenarms. — Partitions not present ; rays fifteen, finely 
punctated. Fossil and alive in the localities named. The discs 
of this species are more arched than those of any other of the pre- 
ceding ones. The fifteen rays terminate in fifteen marginal open- 
ings. The granules are distributed into forty-eight round, yellowish, 
brown-coloured masses, placed around the bright central spot of the 
body, or else appear united as one ball. Locomotion not perceptible. 
Diameter of fossil foniLS, 1 -560th; of living, 1 -560th to 1 -480th. 

A. sedenarius. — Divided by internal partitions into sixteen cells, 
and having sixteen finely punctated rays. The granules of a green 
colour, form, in some, separate concentric masses ; in others, a single 
ball-like mass, placed in the middle of the body. Locomotion not 
perceptible. Alive near Cuxhaven. Diameter 1 -290th. 

A. ododenarius. — Divided by internal partitions into eighteen cells, 
and having eighteen finely punctated rays. This species is very 
similar to the preceding, being only a little larger, and having 
eighteen septa and marginal openings. The granules in one specimen 
consisted of seven large yellowish green masses, placed concentrically 
around the bright central spot of the body, but which did not appear 
to be strictly confined to the divisions or cells, which, most jirobably, 
arises fi'om some optical deception. It was remarkable that, in this 
specimen, the openings were situated at the margin, in the centre of 
each division. The play of colour of these divisions depends upon 
some optical phenomena yet to be developed. In the centre of the 
disc of those species provided with these divisions, is a broad, bright, 
and polished umbilicus-like spot, which is invisible in those not pos- 



312 DESCRIPTION OF {^Polygastiica. 

sessing internal partitions. In sea water, along witli tlie preceding. 
Diameter l-240th. 

AcTiNOCYCLiJS senarius. — Discoid, cellular, with six rays and septa. 
Diameter l-llSOth to l-720tli. Possil in the Schist of Oran in 
Greek marl, and alive in the Baltic. 

(Group 132, Plate III., represents different views of this species.) 

A. hiternarius. — Like the preceding, hut without internal septa. 
Found fossil in chalk, and alive at Hamburgh. 

A. octonarius. — Discoid, cellular, with eight rays and septa. 
Diameter l-576th. Fossil in the chalk marl of Oran with A. senarius, 
but less common. 

A. septenarius. — Eays seven, punctate ; no septa. Diameter 
1-1 060th. to 1 -430th. Fossil in chalk marl, and alive in the Baltic. 

A. Sol. — Foimd by Ehrenberg at the mouth of the Elbe. Cha- 
racters unknown. 

A. undulatus, (Kiitz.) — Eays six; disc flexnose; cells minute. 
Fossil at Eichmond, Virginia. 

A. tredenarius. — I^o septa; thirteen rays. Diameter l-672nd. 
Baltic. 

A. hiseptenarius. — No sejita ; fourteen rays. Diameter 1 -720th. 
Fossil. 

A. quatuordena/rius, with fourteen rays, has also septa. 

A. bioctonarius, with sixteen rays, but differs from A. sedenarius, 
by wanting septa. Size 1 -480th. Island Tjum, Gothland, and 
Hamburg. 

A., septemdena/rius, with seventeen rays. 1- 468th. Bermuda. 

A. hinonarius, with eighteen rays. Chalk marl of -^gina and the 
Greek Islands. 

A. vicenarius. — No septa; twenty rays. Diameter 1 -480th- 
Island Tjorn. 

A. Lima. — No septa; twenty-one rays. Diameter 1 -480th. 
Same locahty. 

A. Ceres. — No septa; twenty- two rays. Diameter 1 -336th. 

A. Juno, with twenty-three rays. 

A. Jwpiter. — Larger; no septa; twenty-four rays. Diameter 
1 -432nd. Cuxliaven. 



N'aviciddcea.] infusorial animalcules. 313 

AcTiNocTCLUs MercuHm. — Large ; no septa ; twenty-six rays. 
Diameter l-432nd. Island Tjorn. 

A. Pallas, with twenty-seven rays. Diameter 1 -288th. Bermuda. 

A. /S'«^«;vms, with twenty-eight rays. No septa. Diameter 1 -432nd. 
Cuxhavcn. 

A. Terra, with twenty- nine rays. Mouth of the Scheldt. 

A. Venus, with thirty rays. Diameter l-216th. Bermuda. 

A. Vesta, with thirty-one rays. Diameter 1 -336th. Bermuda. 

A. Uranus. — No septa; thirty- two rays. Diameter 1 -360th. 
North Sea. 

A. Achar-nahr, mth thirty-three rays, alive. Hamburg. 

A. Aldeharan, with thirty-four rays, alive. Hamburg. 

A. Antares. — No septa; thirty-five rays. (l-288th.) North Sea. 

A. Aquila. — No septa; thirty-six, rays. Alive at Cuxhaven. 
1 -360th. 

A. Arcturus, with thirty-seven rays. Alive at Hamburg. 

A. Betegose, with thirty-eight rays; no septa. (l-360th.) 
Cuxhaven. 

A. Canopus, thirty-nine rays. (l-264th.) Bermuda. 

A. Capella, iovij vajs ; no septa. (1-2 88th.) Cuxhaven. 

A. Fomel-hot, forty-one rays. Alive at Hamburg. 

A. Lyra, forty-two rays. Alive at Hamburg. 

A. Regains, forty-four rays. Same locality. 

A. dives. — No (?) septa; rays fifty-two. (l-360th.) Fossil 
Greek marl. 

A. Opulentm. — Rays fifty-five. Found at Antwerp, &c. 

A. Crcesus. — Rays fifty-five. Alive at Hamburg. 

A. PanheJios. — Large ; no septa ; hundred-and-twenty very fine 
rays. (1-1 80th. ) Mouth Elbe. 

A. velatus. — Septa and rays six ; disc loosely cellular ; surface as 
if overspread by a delicate and finely dotted membrane ; resembles 
A. hiternarius. (l-372nd.) Virginia. 

Genus Actinogontum, (Elu-.) — -Prismatic, not in chains ; tcstules 
sub-orbicular, with seven, or many (?) angles. 

A. septenariiim. — With seven angles. Found fossil in earth from 
Barbadoes, along with numerous Polycystinea). 

Y 



314 DESCRIPTION OF {Poli/gastrica, 

Genus AcTiNOPTTCirtJs, (Ehr.) — Lorica bivalve, in the form of a 
circular disc, with coincident external rays and internal septa. Surface 
cellular. Individuals solitary. This genus differs from Gallmiellaj 
by its individuals being distinct, not concatenated ; from Actinocrjclus, 
by its lorica having both rays and septa ; for Aetinocyclus is destitute 
of internal partitions. 

Tliis genus, instituted by Ehrenberg since Actinocyclus, must 
embrace many species formerly numbered with the latter, — indeed, 
all those with internal septa; and there is no doubt, that those 
having like specific names in the two allied genera, are really 
identical. 

A. terna/rius. — Disc with three septa. Fossil in chalk marl. 

A. qmnarius. — Disc with five septa. Fossil. Richmond, Virginia. 

A. hexcopterus. — Conical, rays or internal septa six, solid ; border 
of disc thick, sinuose, dentate internally. Can it be a calcareous 
■pavHcle of anjEchinoderm, ComopeUa? Vera Cruz. Fossil (P. 14, f. 31.) 

A. nonarius. — Similar, with nine rays or septa. Peru and North 
America. 

A. denarius, with ten radiating septa. Richmond, U.S. 

A. vicenarius, with twenty radiating septa. 

A. Jupiter, with twenty -four radiating septa. Richmond, Virginia, 
(P. 14, f. 28.) 

Other forms are met with having seven, eight, twelve, and seven- 
teen septa, and might, on the same principles as the foregoing, be 
considered distinct species. 

A. qtiaternarius, has four radiating partitions, and consequently 
the same number of intermediate cells. Diameter 1 -552nd. Fossil 
in chalk marl. 

A. velatiis, has six rays, and a loosely cellular disc; its surface 
appearing as if veiled by a delicately spotted membrane. Diameter 
1-3 72nd. 

A. biternarius, is allied to the preceding species, and has the same 
number of septa ; but its surface is adorned with obliquely 
dotted lines. 

A. senarius. — Diff'ers from A. bifernarius only in the sculpturing 
of its sui-face ; fossil, .^gina. 



Naviculacea.^ iNFTJSoniAL animalcttles. 315 

AcTiNOPTYcmjs dives. — Found fossil at ^gina, with last species. 

A. Ceres. — Has twenty-two rays. Diameter 1 -336th.' Virginia. 

A. qxiatmrdeiiarius, fourteen septa and rays. Mouth of the Elbe 
and America. 

A. octonarius, eight partitions ; same habitation ; and in polishing 
powder of Or an. 

A. sedcnarius, sixteen septa. Diameter 1 -288th. Cuxhaven and 
Richmond, Virginia. 

A. octodenariifs, eighteen septa. Diameter 1 -240th, Cuxhaven. 

A. dmdcnarim, twelve rays and septa. Cuxhaven. 

Genus Amphipentas. — Unattached; lorica simple, bivalve, and 
pentagonal. 

This genus is not yet well established, it being open to question 
whether its supposed species may not be fragments of other 
organisms. 

A. alternans. — Pentagonal ; sides concave ; angles obtuse ; the 
angles of the external pentagon alternating with those of a smaller 
central one; the latter has also a cii'cular projection at its middle. 
Cuba. (P. 14, f. 32.) 

Is it a calcareous particle of an Echinoderm ? If Coniopelta ? 

A. Pentacrimis. — Pentagonal ; its dorsal surface presenting a 
striated ring. Diameter 1 -240th. Fossil in Greek marl. Fragments 
like Am/pTiitetras. 

Genus AMPmrLEURA, (Kiitz.) — Frustules solitary, navicular, 
prismatic, longitudinally furrowed ; without central aperture. 

This is one of the genera included in the family ITaviculea by 
Kiitziug, but one not well defined. 

A. pellmida. = Navicida? pellucida, (Ehr.) — Slender, elongated, 
liaear lanceolate, not transversely striated, apices obtuse. (P. 16, f. 1.) 
Length 1-2 76th. to 1 -204th. German Coast and Falaise. 

A. Lanica. — Short, lanceolate, truncate, not striated. (1 -390th.) 
Danish Coast. 

A. rigida. — Elongate, linear lanceolate, truncate ; on one aspect 
straight; on the other sigmoid. (l-168th. to l-144th.) Marine. 
(P. 16, f. 2.) 
y 2 



316 DESCRIPTION OF [ Polygastrica, 

Genus Amphipeoha. — It presents the general characters of Pinnu' 
laria ; but the terminal apertures, instead of occupying the margin^ 
are placed in the median line. Individuals solitary. 

A. constricta. — Smooth ; constricted laterally at the middle. In 
general form resembles Navicula alata. Cuba. (P. 15, f. 1.) 

A. navicidaris. — Oblong, transversely striated ; expanded 
(dilated J on the side, at the middle ; apices obtuse. Has the habit 
of a Pinnularia. Cuba and United States. 

A. alata, (Kiitz). = Entomoneis alata, (Ehr.) — (P. 16, f. 5, 6, 7.) 

A. puJchra, (Bailey.) — Large, deeply constiicted, ends rounded, 
sides compressed, carinate, distinctly striate, and near the margin 
punctate. Central portion narrow, sigmoid, with a few fine longi- 
tudinal lines. Often contorted, so as to bring one half into a plane 
at right angles to the other. Long Island, E[u.dson Piver, &c. 

A. ornata, (Bailey.) — " Small, deeply constricted, ends truncated 
and rounded, sides marked with a longitudinal row of undulations or 
pininilae, as in Surirella. Often contorted. The ruffle-like rows of 
pinnulse distinguish this species fi'om all others. It probably has 
minute striae also, but I did not have an oppor-timity to examine 
with high powers." 

A. quadrifasciata, (Bailey.) — Small, moderately constricted, ends 
truncate or slightly rounded ; sides compressed or Carinate, lanceolate, 
with the apices produced and rostellate. "VYhen living, each specimen 
was marked by four ti'ansverse yellow bands. A high power shows 
the surface to be veiy minutely striated. 

Genus Amphora. — Frustules solitary, with two central apertures,^ 
one on each side the median line, but without terminal ones. 

The double umbilicus is the distinguishing feature by which it 
differs from the sub-genera of JVavicula. It is a member of Kiitzing's 
fiimily JSfaviculece. 

A. amlis = Navicula (?) Amphora. — Tui^gid, oval, ends broadly 
rounded, truncate ; margin closely striated ; and very fine longitu- 
dinal median lines; striae very fine, nine in 1- 1200th; (1 -456th to 
1-1 20th.) Fresh water (P. 3, f. 153.) 

A. affmis. — Oblong, narro\ving gently towards the widely truncate 
ends ; margin longitudinally sti'iped, and very fine longitudinal 
lines traversing the centre. (l-9G0th to l-390th.) 



2^aviculacea.] infusokial animalcules. 317 

AMpnoRA lineolata = Navicula lineolata. — Elliptic-oblong ; turgid 
at the middle ; apices somewhat elongated, but truncate ; with strong 
longitudinal lines on the margin, and very fine ones in the centre 
portion. (1 -480th to 1 -140th.) Venice, Vera Cruz, Peru. 

A. Veneta. — Minute; in one aspect, elliptic-oblong ; in the other, 
semi-elliptic; apices truncate. (l-1200th to l-1080th.) Venice. 

A. elliptica. — Imbedded in amorphous mucus ; lanceolate-elliptic ; 
transversely striated on the margin ; apices rather attenuate, but 
obtuse and truncate, with a central single aperture. Baltic. 

A. afonina. — Lanceolate-elliptic, extremities produced; truncate, 
without longitudinal lines. (l-1080th to l-650th.) In hot springs. 

A. Coffeaformis = JSfavicula (?) quadricostata. — Lanceolate, apices 
produced, obtusely rounded; with four strong longitudinal lines on 
the margin, and some very fine ones in the centre. (l-1720tli to 
l-480th.) In mineral water, Carlsbad. 

A. hyalina. — Hyaline; elliptic-lanceolate, and more or less acute; 
traversed by a very few delicate longitudinal lines. (1 -600th to 
1 -432nd.) Baltic. 

A. acutiuscula. — Lanceolate, ends acuminate, and rather acute ; 
strong longitudinal marginal stripes. (l-576th.) Genoa. 

A. lorealis. — Very small ; oblong-lanceolate ; in some, ends more 
acute than in others. Length^l- 1200th. In rock streams, Heligoland 

A. (?) Atomus. — Very minute ; on one side elliptic, and ends 
rounded; on the other, linear and truncate. (1 -2640th.) 

A. gracilis. — Small, oblong, and having a delicate longitudinal band ; 
apices truncate ; margin transversely striated. Mexico. (P. 15, f. 26.) 

A. navicularis. — Small, boat-shaped (navicular) ; apices acute ; 
lorica transversely striped throughout. (P. 15, f. 37.) This may 
prove to be a CymheJla or a Cocconema (Kiitz.) 

A. (?) carinata. — Large, navicular ; plane on each side, extremities 
acute ; striae in four lateral fasciae. (1 -240th.) Island of Tjorn. 

A. crystalUna. — Smooth, convex dorsaUy ; concave ventrally ; 
broadly ti-uncate at each end. (l-432nd.) Tjorn. 

A. fasciata. — Dorsum convex in the middle ; venter plane ; with 
closely set and slender longitudinal rows of striae, about twelve in 
number; ends, widely truncate. (l-456th.) 



318 DESCEIPTION OF [Polygastrica. 

AnrnoRA Lyhica. — Dorsum convex its entire length ; venter con- 
cave; sides punctate; striate on their inner margin. (1-2 8 8th.) Found 
in the Oasis of Siva, Mexico, XJnited States, &c. (P. 15, f. 38.) 

A. rimosa. — Discovered and named by Ehrenberg, among other 
American Bacillwria. 

A. Fischeri. — Turgid at the middle, ends widely truncate ; thi'ee 
longitudinal marginal lines ; central lines obsolete. (1-5 76th.) Carls- 
bad. Probably a variety only of A. Coffeaformis. 

A. Amj^hioxys (Bailey.) — Ventral side rectangular, with slightly 
rounded ends, and two arcuate bands of stria?, which are broadest 
near the centre ; back convex, minutely striate ; sides convex above, 
minutely sti'iate ; concave below, strongly striate ; ends produced and 
rostellate. The side view of this species bears a striking resemblance 
to Eunotia amphioxxjs (Ehr.) 

Genus An ATJXirs. — Lorica simple, bivalve, compressed, subquadrate; 
spontaneous fission complete, hence no concatenation. This genus 
approaches BiddulpMa by the constrictions on its sides, but is without 
tubular processes, and lateral aperiures. 

A. scalaris. — Smooth, turgid in the young state ; but when full 
grown, very wide and much flattened, with foui', six, eight, fourteen 
lateral constrictions, which give it, when viewed on the side, a 
ladder-like (sealarifoiTti) appearance. Diameter 1 -480th to 1-1 80th. 
Antarctic Ocean, 

A. campy locUsmcs. — Quadi'angular ; each valve very much com- 
pressed, triangular, with obtuse angles ; with two slight constrictions 
laterally. It has the habit of an unequal-sided Triceratium, or of a 
Campylodisctis. Diameter 1-3 72nd. Bermuda. 

Genus Aeachnoidiscus (Dcane.) — Lorica circultu", discoid, bivalve, 
divided into cells (locuK) by incomplete septa ; centre of disc clear, 
occupied by a foramen, surrounded by denticles, equal in number to 
the rays, and ^\'ith an external contiguous circle of puncta (foramina.) 
Interspaces between the rays occupied by fine concentric or trans- 
verse lines ; also, at the periphery, by short projecting septa. 

The disc, in its markings, has been compared to a spider's web — 
hence the name. Its affinity is with Autinopfychus. Mr. Shadbolt 
has ijitijnatoly examined the structuie of the shell. He says — "It 



Navicalacea.'] infusorial animalcoles. 319 

is not strictly bivalve, although capable of being separated into two 
•corresponding portions ; but is more properly multivalve, as con- 
sisting of two discoid portions, and of two annular valves, exactly 
similar respectively to one another. Each discoid valve is further 
separable into an outer, very thin, somewhat flexible, and elastic 
membrane, on which are the characteristic spider's wcb-like mark- 
ings. (P. 24, f. 18) ; and a silioeous frame- work, resembling 
a circiilar gothic window. (P. 24, f. 19.) . . . It is indisputably 
evident, that a central opening is present, partially covered inter- 
nally by a delicate cup-like process (membrane), so as to form a 
species of valve. The two annular valves are situated between the 
two discoid ones ; and thus the whole shell, in its natural state, 
resembles a circular snuff box. These valves consist of a siliceous 
ring, within Avhich, (extending a slight distance towards the centre) 
is an annular membrane, and when in situ, the valves are placed so 
that the membranes of each valve are in contact ; and thus the 
space included between the two discoid valves is partially divided 
into two (not three) chambers." (Trans. Mic. Soc. V. 3, p. 49.) 
Mr. Deane has supposed the presence of a short siliceous pedicle ; 
but Mr. Shadbolt is satisfied there is none, but that all the shells 
are sessile. The latter thinks it probable, they may propagate by 
self-division ; yet they occur of all imaginable diameters, from 
4-lOOOth to 14-lOOOth of an inch, and the number of rays, in each 
individual, is by no means constant. 

It should be added, that this same observer is disposed to consider 
them animals, and that he supposes food to be taken in through the 
openings about the centre, not improbably by tentacula, arranged 
like those of Madrepores. (P. 24, figs. 18 to 21.) 

AEACHifoiDiscus Joponicus. — Specific characters unknoAvn. So 
named, because found on Algse, from Japan ; used as an article ol food. 

Mr. Shadbolt intimates the existence of other species, found in 
Ichaboe guano ; Algse from the Cape of Good Hope; from I^orth 
America, &c. 

Genus Asterodiscus (S. Johnson.) — Lorica simple, bivalve, siliceous, 
circular ; fi^om the side bi- convex, not forming chains. Umbilicus 
smooth, nearly circular ; divided from the margin by imperfect septa, 
of Avliich every two unite half way to centre ; the rest radiating 



320 DESCRIPTION OF l^Polygastrica. 

between the septa, umbilicus produced to margin by radii, which are 
smooth and flat — the one preceding between the two united septa, 
smaller than the other. Spaces between radii elegantly marked by 
dots, aiTangcd in eccentric cui'ves. It diiFers from Asterolampra, 
where all the divisions are symmetrical ; from Asteromphalus, the two 
umbilical septa are nearly parallel, and the corresponding marginal 
radius is wanting. Three si^ecics were found by A. S. Johnson, Esq., 
in Piscataway and E,ichmond, (N. A.) earths; fossil guano from the 
Chiacha Islands off the coast of Peru ; and in the Bermuda earth, 
along with specimens of Asterolampra 8eptenaria, and JSupodiscus ? 
Tripes, (Silliman's American Journal, 1852.) 

A. qidnarim. — Five marginal radii and umbilical divisions. 

A. senarius, with six radii and divisions. 

A. nonarius, with nine radii and dii-isions. 

Genus Asteholampea, (Ehi'.) — This genus is intermediate between 
Actinocyclus and Actinoptychus. Lorica simple, symmetrical, bivalve, 
and circular; divided by imperfect internal partitions (dissepiments,) 
alternating with the perfect radii visible on the surface. Form very 
elegant ; but fission being complete, it does not occur in chains. 

A. Maryland ica. — Pays eight, reaching the margin ; and as many 
alternating partitions, radiating also from the centre, but incomiilcte, 
Curved rows of puncta occupy the interspaces. Diameter l-192ud. 
(P. 14, f. 33.) 

Genus AsTEE.OMPHALTJS,(Ehr.) — Lorica simple, symmetrical, bivalve, 
and orbicular. Fission complete ; hence individuals not found in 
chains. Each disc marked by alternating rays, giving the appearance 
of a double star. Umbilical rays (imperfect partitions, septa) not 
attaining the margin, two parallel, the rest divergent. Marginal 
rays smooth, plane, and one of them, in aU species and individuals, 
wanting, or so obsolete, that two umbilical, one on either side of it, 
become parallel, 

The fossil American genus Asterolampra, approaches nearest to 
Asteromphalus, but differs from this by all its rays being perfect, and 
by their alternation and divergence being also perfect and symme- 
trical. 

A. Darwinii. — Umbilical rays, five ; flexuose, with four marginal 
rays, the fifth obsolete. Diameter 1 -960th. Antarctic Ocean. 



Naviculacea.] infusorial animalcules. 321 

Genus Asteromphaltjs, (Ehr.) Tfookem. — Six umbilical rays, 
straight; five marginal rays, the sixth obsolete. (1 -420th.) Antarctic 
Ocean. 

A. JRossii. — Six inflected umbilical rays ; five marginal, the sixth 
obsolete. (l-504th.) 

A. Buchii. — Seven straight umbilical rays ; six marginal, the 
seventh obsolete. (1 -504th.) 

A. Beaumontii. — Seven inflected umbilical rays ; six marginal, the 
seventh obsolete. Diameter l-648th. 

A. Humholdtii. — Eight straight umbilical, and seven marginal rays, 
the eighth marginal obsolete. Diameter l-372nd. (P. 14, f. 34.) 

A. Cwvierii. — Nine umbilical straight rays, and eight marginal, the 
ninth marginal wanting. Diameter 1 -392nd. Antarctic Sea. 

Genus Atjlacodiscus. — Lorica composed of two equal valves, 
orbicidai' and unilocular (one celled), with apertures on each valve 
near the margin ; very shortly tubular, and severally continued to 
the centre by a distinct furrow (sulcus.) 

Aulacodisci are Eupodisci, furnished, in the place of pediform 
tubules, with bands radiating fi-om the centre, and becoming con- 
nected with the tubercles seated just within the margin, and having 
the surface of their valves granular and not cellular. 

A. crux. — Testules rather convex ; margin finely radiated, forming 
a rim around the cellular, granular disc ; twelve pearl-like granules 
in l-1200th, and some rows of gi-anules radiating from the centre, 
with four series representing a crucial suture, stronger near the 
margin. Diameter 1-3 84th. Eichmond, Yii'ginia. 

Genus Auxiscus. — Lorica bivalve, cylindrical (or orbicular) mul- 
tiplying by perfect self- division; two large (not tubular) apertures 
on each surface of the disc laterally, which also is not curhose. 

This genus differs from Cerataulus, in wanting the cirrhose surface 
of the lateral discs, as also the tubular apertures. 

A. cylindricus. — Cylindrical, with a plane orbicular disc on each 
side, having a rim, and a central area figured by various radiating 
lines ; Avith two opposite apertures, opening obliquely on the margin. 
<l-576th to l-288th,) 

A. (?) gigas. — Margin of the sides tumid and perforated, sculp- 



322 BESCBiPTioN OF [Potygastrica 

tured by elegant rows of dotted, imperfectly radiant lines. (l-348th.) 
^gina. 

AuLiscTJS polystima = Coscinodiscus polystigma, of the Frisian Sea. 

Genus Bacillaeia, (Ehr.) — Lorica bivalve, or multivalve, in the 
form of a many-sided prism. Self-division complete ; but the fnistules 
do not entirely separate at their angles, and thus they form gaping 
or zig-zag chains (figs. 166 to 170); even when thus connected 
together they are motile. " The organs of locomotion," says 
Ehi'cnberg, " are soft peg-like processes, projecting from a longitu- 
dinal cleft ; in B. tabellaris, transparent polygastric vesicles have 
been seen. Two openings are visible at the end of the lorica ; 
hitherto the nutritive organs have not been demonstrated by artificial 
means. At one time it was supposed these animalcules had no mouth, 
but were nourished by absorption. Self-division always longitudinal 
and dorsal, so that the surfaces which hang together are those of the 
sides. A small deflection and locomotion of the chains is observable 
in the fresh water species, but is more remarkable in the marine 
varieties of B. paradoxa, which, when separated, move quickly, like 
Kavicula. The name Bacilla/ria was first given to them by G. Malin ; 
botanists gave them the names of Liatoma, Conferva, and Oscillator ia. 
They form part of the genus Vibrio of Midler." Nageli states, the 
individuals of this genus possess anucleus. See genus Biatorma (Kiitz.) 

B. paradoxa Vihrio paxillifer (M.) — Lorica straight, slender, stria- 
ted ; often fifteen times longer than broad. Nine striae occur 
in l-1200th. It is of a yellow ochre colour, and its locomotion is 
distinct. In consequence of incomplete self- division, the frustules 
adhere side by side, and the band-like clusters thus formed are either 
straight, wavy, or zig-zag, according as they slide one upon another. 
The individuals forming the chain, can detach themselves, and then 
move freely about like Nmicula. Group 167 is a polype-like cluster, 
and fig. 166 a front and side view of a single specimen. Found 
upon sea-weed. Length 1-1 150th to l-240th. 

B. vulgaris = Diatoma vulgar e (Kiitz.) — Straight ; three or four 
times longer than broad. It has thirteen transverse stria) in 
1-1 200th. Fig. 168 is the dorsal view of part of a group of foiu- 
specimens ; viewed sideways, they resemble a spindle. Found fossil 
and alive, both in fresh and salt water. In the Ehone, it covers over 
confer ca ghmcrata, in the form of a thick felt. 



Kavictilacea.'] infusoeial animalcules. 323 

Kiitzing says : " The connected band of frustules (lorieaj) is attached 
by an elongated, but inconspicuous stulli." Length 1 -570th to 
1 -430th. 

Bacill-Iria pect mail's = Liatoma temie (Ag.) — Slender, striated; 
often thi'ee to six times longer than broad ; of a brownish yellow 
colour; striae nine in l-1200th. Kiitzing aiflrms that the chain is 
affixed by an indistinct stalk. Length 1 -3240th to 1 -430th. In 
fresh and stdt water. 

B. elongata = Biatoma Ehrenbergii (Kiitz.) — Striated, slender, 
slightly contracted in the middle (P. 3, f. 169.) Striae twelve in 
l-1200th. Chain fixed by a very minute stalk (Kiitz.) Length 
1- 1150th to 1 -240th. In ponds, common. 

B. cuneata. — -"Wedge-shaped (cuneate), striated (fig. 170), margin 
with a few teeth ; length not double the width ; lateral view ventri- 
cosc, lanceolate. It approaches near Odontidium mesodon (Kiitz.) 
Length l-1150th to l-1200th. Fresh water. 

B. Cleopatra = Grammatophora tnarina (Kiitz.) — Oblong, destitute 
of striae ; colour golden yellow. "Was found by Ehrenberg near the 
ruins of the Baths of Cleopatra, in Egypt. Length 1-5 70th to 1 -480th. 

B. (?) tabellaris =^ Tahellaria flocculosa (Kiitz.) — Smooth, narrow, 
slightly enlarged at the middle ; frustules occuring in the form of 
square plates; granular contents yellowish. Length 1-1 150th to 
l-960th. In fresh water on Conferva. 

B. flocculosa. — Smooth, almost square, not enlarged at the middle. 
In ponds and streams. Length 1- 1440th. 

This, and the two following species, Kiitzing considers to be repre- 
sented by his Biatoma pectinale. The lateral \'iew he describes to be 
sharply lanceolate. 

B. seriata. — Slender, straight, eight to nine times longer than 
broad ; smooth ; the contained granules occur in four to five masses. 
Length 1 -360th. In slow streams and ponds on Conferva. 

B. Ptolomai. — Smooth, very small, length t"\vice or thrice the 
breadth. Colour pale. Found in Alexondi-ia. Length ] -3600th. 

As a member of this genus, Niigeli describes the following 
organism ; — 

Each cell or segment has the form of a column, the bases of 
which are cUipses. The axis is rather shorter than the long 



324 DESCRIPTION OF [Poli/(/astrica. 

diameter of the bases ; hence the cell appears almost square (P. 24, 
f. 28) on the broad side, on the narrow side a longish rectangle. On 
the bases are four ribs, parallel with the broad diameter of the ellipse 
The bases also present many slight indentations. The ribs are merely 
in the membrane, as may be ascertained by a side view. They 
extended, however, a short distance on both sides, over the lateral 
surface of the cylinder, and are gradually lost. The nature of the 
ribs is not to be made out in these plants, from analogy to the 
above-described (see genus GaUioneUa nov. sp.) It becomes probable 
that they are formed by secreted extra cellular substance. Sec 
description of Plate 24, figs. 26, 27, and 28. 

The cell-contents consists of a colourless transparent fluid, and a 
free nucleus-like heap of chlorophyl, mingled with mucilage In 
propagation, this green mass divides into two parts, between 
which the septa appears. 

: Among the Bacillaria figured by Ehrenberg, it exhibits the 
greatest affinity to B. cwieata, and is almost of the same size, viz- — 
l-1152nd to l-1200th. The latter, however, is distinguished. — 1. 
By the alternating broader lateral borders. 2. By the individual 
cells remaining attached together at one angle after division. 3. By 
the strife not being straight upon the dividing wall, and not parallel 
with the axis, but running at an oblique angle over the broad lateral 
surface ; and 4. By the additional existence, on both sides, of two 
striae on the lateral margin (on the narrow lateral surface.) 

Unlike the ordiuaiy members of the genus Bacillaria, the indivi- 
duals of the species in question only remain united together imme- 
diately after the division of the parent cell, subsequently they are 
completely separated, or, in other words, are free. (Bay Society, 
1844, p. 267.) 

Some of the preceding species of Bacillaria will be found again 
referred to, with additional matter, under the genus Biatoma. 

Genus Biblaihtjm. — Lorica tabular, made up of many lamina ; 
transverse in relation to the length ; central portion smooth, but the 
lateral segments, like the covers of a book, ornamented with trans- 
verse striae. The smooth central portion of each individual, is 
furnished with a large umbilicus at its middle. There are quadi'an- 
guLir, elliptical, and cylindrical varieties in this genus. 



Naviculacea.] iNFrsoRiAT, antmalcules. 325 

Bihlarium is intoitnediate betwcon Tessella and Tahellaria ; it 
approaclics Striatella, but differs from that genus by the absence of a 
pedicle. 

All the species hitherto met with are fossil. Ehrenberg siipposea 
them, fi-om their geological position and I'elations, to have been in- 
habitants of brackish water. 

The above characters are gathered from a report on a paper by 
Ehrenberg, read before the Berlin Academy. 

BiBLAEiTJM Glans = Navieula (?) Glans. — Laterally valves oblong, 
tumid at the centre, apices obtuse ; with loose parallel striae, seven ta 
eight in 1- 720th, or four to six in 1 -1440th. No suture visible. 
Length 1 -480th. Finland, Siberia, and Oregon. 

B. (?) gihhim. — Smooth, bacillar ; two, three, or foiu' concatenated; 
straight at the centre ; laterally, gibbous at the centre. No central 
aperture observable. Length 1-11 52nd. Kurdistan. 

B. compressum. — Laterally narrowly elliptic ; lanceolate, obtuse, 
with loose, transverse, parallel pinnae, interrupted by no median 
suture, and five to seven in 1-1 152nd. Length 1 -648th. Oregon. 

B. castelliim. — Ovate, obtuse ; with four marginal sinuses on each 
side. Lateral valves not observed. Length 1 -900th. Siberia. 

B. (?) Crux = Navieula crux. — Lateral valves quadrangular^ 
striated ; deeply and unequally angular, so as to resemble the figure 
of a cross; with transverse parallel striae, interrupted by a median 
suture; eighteen in 1-1 152nd. Length 1440th to l-864th. Fossil, 
Hesse Cassel; living and fossil in Siberia. 

B. ellipticiim. — Lateral valves elliptical, striated transversely; with- 
out a suture. Stiiae five to eight in 1-1 152nd. Length 1 -1080th. 
Siberia and Oregon. 

B. emarginatum. — Lateral valves quadrangular, unequally and 
deeply angular, assuming a crucial form, with two opposite (ventral) 
obtuse and emarginate rays ; transverse striae strong, but lax, seven 
in l-1152ud. No suture. Length 1 -864th. Siberia and Mexico. 
"I have seen nineteen leaflets concatenated, and two such collections 
(Kbelli) also connected" (Klitz.) 

B. (?) Follh, of North America = Navieula (?) FoVis of Europe ; 
but would perhaps be more rightly transferred to Tahellaria. — Lorica 
depressed, swelled at the middle, without longitudinal striae. It i 



326 DESCKIPTTON OF [Polygastriccl. 

deficient of the margin frimaj and suture of Navicuh, and the 
central aperture appears too small. Length 1 -2300th. Massachusetts. 
BiBLAEiUM Lamina. — Lateral valves widely linear, rounded at 
the ends, sliglitly constricted in the middle; suture absent; pinnules 
seven to eight in l-1152nd. Oregon. 

B. Lancea. — Lateral valves lanceolate ; apices subacute ; pinnules 
parallel, three to eight in 1-11 52nd. Sutui'e wanting. Length 
1 -336th. Oregon. Ehrcnberg has met with twenty-seven valves 
concatenated. 

B. lineare. — Lateral valves naiTowly linear, rounded at the ends or 
subacute; not contracted at the middle; striae lax, strong, four to 
eight in 1-1 152nd. No suture. Length 1 -552nd. Siberia and Oregon. 
B. Rhombus. — Lateral valves ovate, rhomboid, quadi'ate ; apices 
subacute ; median angles more obtuse ; stiise lax, six to eight in 
1-1 152nd. No suture. Le'ngth 1 -864th. Siberia and Oregon. Some 
examples are met with having more acute median angles. 

B. speciosum. — Lateral valves elongate, turgid at the centre and at 
each end; broader on the ventral surface ; one extremity frequently 
subacute, the other more obtuse ; pinnules sti^ong, but lax ; suture 
obsolete, not altogether absent. Striae four to eight in 1-1 152nd. 
Length 1 -336th. Oregon. 

B. Stella. — Lateral valves quadrangular, unequally sinuated, hence 
a crucial outline ; striated ; ends obtuse ; strite parallel, lax ; sutm-e 
absent. Length 1 -696th. Oregon, Siberia. 

Genus Campylodisctts. — Valves equidistant, (not concave) ; indi- 
viduals (frustules) solitary, or temporarily, during self-division, in 
pairs ; disciform ; tortuous or saddle-shaped ; elliptic, sub-orbicular ; 
striated, striae mostly radiate. 

Further views of this genus are enunciated in the description of 
C. ITorologium. 

Campylodlscm is a member of the family Surirellem, of Kutzing ; 
it api^roaehcs Jfe^sw-fls {Gallionelh, 'Ehx.), but differs in having an 
elliptic instead of a circular disc. 

"The species, (says theHev. ^Y. Smith) included under this genus, 
may all be recognized by the characteristic bend or contortion of 
their surfaces, which gives to the frustule, under certain aspects, the 
semblance of a miniature saddle. Kiitzing has indeed removed from 



Nuviculacsa.] iNFrsoniAL animalcules. 327 

CampT/lodiftnifi, and placed in Surirella, several species possessing this 
character, apparently for no other reasons than that the stria3 or 
costae are confined to the margins of the valves, and are parallel, not 
radiate. When we consider that the striae are often exceedingly 
difficult of detection, and that their direction, merely, cannot be 
regarded as necessarily implying an important difference in internal 
structure, the circumstances alluded to do not seem a sufficient ground 
of exclusion, and it -would perhaps be as well to allow Campyhdiscus 
to include all those species with equidistant valves, to which its 
very significant name can with propriety be applied." (Ami. Nat. 
Hist. V. 7, 1851.) 

Campylodisctjs radiosus. — Small ; its centre smooth, and sending off 
about seventy closely set and broad rays. Fossil. Vera Cruz, Mexico. 

C. (?) striatus. — Centre smooth as in preceding, with two series 
of thirteen parallel transverse striae on each side of a clear interval. 
Fossil. Vera Cruz, Mexico. 

C. Clypeus. = Cocconeis clypeus. — Sub-orbicular ; with the rays 
interrupted (broken) by a smooth band ; punctato-rcticulate at centre 
of disc. Diameter l-576th. to l-216th. Fossil in Franzensbad 
Bohemia. Original drawings of this elegant fossil are given in 
P. 12. f. 516, 518. 1 ' 

C. noricKs. — Sub-orbicular, with continuose (unbroken) rays, seven 
in l-1152nd. ; smooth at the centre. Diameter l-432nd. Alive at 
Saizberg. Fossil at San Fiore. 

C. Remora. — Sub-orbicular ; rays interrupted ; centre of disc- 
smooth. Diameter 1 -480th. Alive at Wismar, on the Baltic. 

C. EcJieneis. — Sub- orbicular, porous ; having continuous rows of 
pores extending from the smooth, solid, central area. Diameter 1-2 8 8th. 
"Wismar, Baltic. Alive. 

C. vulcanicus.—'Lax^e, sub -orbicular; centre smooth; margin wide,, 
with about foi^ty-two rays. Diameter 1 -480th. Peru. 

C. hihernicus. — Testules large, sub-orbicular, with continuous 
(unbroken), loosely disposed rays, four in 1-1 152nd. Rays rough; 
centre smooth. Ireland. 

The following species have been recently described by the Eev. 
"W. Smith. 

C. co-status. — Valves orbicular ; costte distinct, radiate, about forty- 



32S ijESCRiPTioN OP [Polygastncd. 

four ; centre of disc smooth or minutely punctate. Average diameter 
1 -230th. A fresh water species, living and fossil in Great Britain 
and Ireland. 

It aj^proaches C. radiosus, (Ehi\); but its cortas are more numerous 
and longer. 

It may possibly be identical with C. noricus, (Ehr.) 

Campylodiscus spiralis. = Surirella spiralis, (Kiitz.) — Valves 
elliptical ; frustules twisted so as to present a spiral outline ; costae 
distinct, about sixty, parallel or slightly radiate ; centre smooth or 
minutely punctate. Average length l-170th; breadth l-400th. 
In fresh water, Guildford, Surrey. 

C. crihrosus. — Valves orbicular; disc marked with radiating lines 
of minute perforations, crowded towards the margin. Diameter 
l-240th. This probably = C. JEcheneis, (Ehr.), but the description 
of the central area in that species as solid, i. e. unperforated, will 
not apply to the present ; the perforations extending over tlie entii'e 
surface, though, more distant, and somewbat scattered in the middle. 

C. parvulus, (Smith.) — Valves orbicular ; disc traversed by two 
parallel ridges ; striae about twelve, nearly parallel. Average 
diameter l-550th. Poole Bay, 1848. This species is readily dis- 
tinguished by its minute size;, and the ridges on its valves, which 
are very prominent in certain portions of the frustule. It does not 
appear to have been noticed, either by K tzing or Ehrenberg. 
(P. 24. f. 22, 23.) 

C. Horologium. — Disc orbicular, slightly saddle-shaped ; centre 
smooth ; margin radiated. Mr. Williamson, who describes this as a 
new species, dredged off the coast of Skye, states, the disc to be 
less curved than the Bohemian C. clypeus, and still less so than the 
C. zonalis of Mr. J. Phillips. Around the smooth disc is a circle of 
short elegant projecting radii, which extend nearly to the periphery, 
and give to the whole the general aspect of the face of a clock or 
watch, the radii representing the figures marking the houi's. 
Within this ring, and closely bordering tlie inner extremities 
of the rays, is a circle of very minute and slightly elongated 
tubercles, like those which surround the central siliceous umbo of the 
Arachnoidiscus Japonicus, but much smaller. There are usually 
four or five of these to each inters])acc, separating the rays. A 



Xaviculacea.'} iNFtrsoRi.vL animalcules. 329 

smaller circle, but with the tubercles rather more consj)icuous and 
elongated, comiects the outer extremities of the rays with the extreme 
margin of the disc. On the more elevated portions of the inflected 
disc, the rays appear to be rather stronger than elsewhere. Diameter 
l-145th. 

" My specimens consist of at least three layers, inclosing two 
iinicr cavities, which contain a green endochrome. In this it 
resembles many other allied forms. From what has appeared a 
single disc of Arachnoidiscus Japonicus, I have scpaiatcd as mrny 
as six siliceous layers. 

" This seiiaration into lamina, marking the existence of so many 
distinct frustules, reminds us of Melosira and its allies ; a resem- 
blance that becomes the more striking, when we consider, that, as in 
Melosira, the fii'st frustules of Arachnoidiscus, Cocconeis, and many 
others, are attached as parasites to some other body. In the analy- 
tical table of the Baeillaria, page 221, Ehrenberg includes many of 
these objects; classing Cocconeis, Actinocyclus, and what he calls 
Baeillaria, together in his group of Navicul<B, and characterizing 
them as free, in contra -distinction to his fixed forms, in which latter 
he includes Mhnia and other genera. It appears evident, however, 
that Cocconeis and Arachioidiscus arc las 'fixed' when found «i situ 
as any of the Diatomacece ; and probabl)^ many of these other allied 
genera will eventually be found to exhibit the same features when 
better known." 

Campylobiscus Argus (Baile3^) — Large, circular, and saddle- 
shaped, surface marked with rows of conspicuous dots ; margin 
smooth, with a row of pinnule, placed at a short distance from its 
edge. A fine, large, and very distinct species, which appears 
to be widely difiused in the estuaries of the United States. 

Genus Ceeatatjltjs, (Ehr.) — Lorica bivalve, sub-cylindrical, or 
sub-orbicular ; multiplied by perfect spontaneous fission ; hence 
not concatenate; with two tubular apertures, and as many cirrhi, 
alternate with them, on each surface of the lateral disc. 

This genus and Auliscus connect Zygoceros with Campylodiscus, 
and differ in the same manner as do Biddul/phia and DenticclJa which 
present concatenated, or imperfectly separated forms. Ccrataulus =^ 
non-conc^tenate Denticella. 
z 



330 DESCRIPTION OF \ Poli/gasfrifa. 

CEE-iTAiJLTJS turgidus. — Poi-es aggi'egated in a band on the margin 
of eacli valve of the testules. In foiin it is always tortuous. 
Piameter 1 -432nd. Found in the Baltic Sea. 

Dr. Bailey describes this species as foUows : — "Frustules globular, 
or slightly compressed, with two large rounded prominences at each 
end, cohering by alternate angles, forming zigzag chains. Between 
the two rounded processes, and in a plane at right angles to that 
containing them, are placed two long horn-like processes. Two 
frustules are often connected by an external decussately punctate 
ceU, as in Isthnia and Biddidphia.''^ 

Genus Cebatoneis. — Indi^dduals solitary ; lorica prismatic, quad- 
rangular, bivalve, and rostrate, with a central umbilicus, from which 
two longitudinal fiuTows may be traced into the prolonged horns 
(beaks.) Self-division complete ; hence indi^-iduals not chained, 
though sometimes fomid in pairs. 

The general figui'e of Ccratoneis is that of Kavicida, but with the 
apices much produced. In Klitziag's arrangement it is a member 
of the family Wmiculete. 

C. Closterium. — Setaceous and lunate in figure ; central portions 
linear lanceolate ; horns very long, twice the length of the body ; 
granular contents brownish giiecn, occupying only the central part, 
the horns being colourless ; lorica smooth ; in form it resembles 
Closterium setaceiim ; movements active and gliding. Abundant in 
the sea at Cuxhaven, &c. Length l-290th. to 1 -144th. Body 
without horns, 1-1 150th. (P. 15, f. 59.) 

C. fasciola. — Linear lanceolate ; horns shorter than the body, but 
curved in opposite directions, so that the lorica resembles the letter S. 
The body without the horns is like Navicxila gracilis. Locomolion 
distinct. Length l-430th. Cuxhaven. (P. 15, f. 60, 61.) 

C. Greta. — jSra\icular, smooth, rather constricted and flattened in 
the middle; apices acute, straight, not much produced. (l-576th.) 
Chalk marl, Sicily. 

C. laminaris. — Broadly lanceolate, transversely striated on the 
margin ; beak short. Mexico. 

C. arcus. = JSfavimiJa arms. — Narrow, linear, curved, smooth ; 
dorsxun convex, rather dilated in the centi'e of the ventral sui-face ; 



yai'iculacca.] iNFrsoRi.vL axtmalcules. 331 

apices elongated, tapering, rcciu'ved. Length l-o70th. Fresh 
water. (P. 3, f. 147.) 

Ceeatoxeis s/;/>«^/.'?, (Kiitz.) — ]!^arrowly lanceolate, the flat beaks 
sj)irally t\visted, and somewhat obtuse at the cuds. Length 1 -240th. 
On the sea coast. (P. 16, f. 9.) 

Genus CnjEiocEKOs. — Concatenated ; lorica of two equal turgid 
valves, with two apertiu'cs on each side, which, at the earliest period, arc 
very shortly tubular when the corpuscles are contiguous, but are 
afterwards produced as long cornua Avhen the corpuscles become 
remote. The cornua become transformed ultimately into very long, 
slender, and siliceous entangled threads. 

Tliese singular forms have a distant resemblance to Denticella ; and 
individual corj)uscles have the habit of Peridinia. The filament- 
like cornua, detached, may be mistaken for GaUionelloi. 

C. d'lchccta. — Each testule smooth ; the two horns of each side 
often flexuose, and in course of time very long and liKform. 
Diameter of each corpuscle, Avith the cornua, 1-11 o2ud. to 1- 720th. 
Antarctic Sea. 

C. tetrachata. — Smooth ; horns four on each side, becoming very 
long, and filiform. Diameter l-1152Tid. 

C. (?) Bacillaria. — ^Bacillar; breaath three to four times greater 
than depth ; tnmcate at each end, and fiuTiished Avith two long 
filiform cornua. Diameter 1 -864th. Bermuda. 

C. (?) Diploneis. — Constricted at the middle, rounded at each 
end, with the habit of Diploneis, but with two filiform cornua from 
each end. Diameter 1 -960th. Bermuda. 

The two preceding forms Avere fii'st observed and figm-el by 
Dr. Bailey. 

C. didymus. — Smooth, width double its heighth, Avith two semi- 
orbicular angular valves, almost of the character of Eiiastrum, Avith 
two decussating filiform cornua fi'om the middle of each side. 
Largest diameter 1-1 080th. Fossil in African Guano. Goniotheciimt 
Gastridiiim found along with the preceding, may belong to the same 
genus, but having, in its fossil state, its cornua broken off. 

Genus Coccoxeis. — The skield-Uke Navicida. Lorica bivalve, pris- 
matic, or someAvhat hemispherical, Avith two apertures, one in the 
z 2 



332 DESCRIPTION OF [Pul^ffagtriea. 

middle of each piece, but without terminal pores. Never developed 
in the form of a chain or cluster ; propagation by self- division, or 
gemmules, is doubtfnl ; mostly striated ; the transverse striae appear 
to be internal flutings like ribs. The lorica is composed of two lateral 
pieces, joined together at a central fiirrow, somewhat resembling the 
keel of a boat, the under surface being flat, the upper somewhat 
arched. A foot-like process has been seen projecting out of the 
central opening, on the under surface. The internal matter is green 
or yellow, and often appears to be fonned in two plate-like masses. 
Though actual motion has not been observed, change of place appears 
to ensue. 

Kiitzing makes Cocconeis the type of a family Cocconeidm, order 
Stomatic(B, (see page 308.) In defining the genus Cocconeis he is at 
variance with Ehrenberg, in stating that its members are ultimately 
adnata (attached) and sessile. 

Cocconeis bears the greatest resemblance to Exinotia (Ehr.) and 
Upitliemia, (Kiitz.) but is at once distinguished from them by 
having a central aperture, whilst it wants terminal openings. The 
central umbilicus is found only on one siu'face ; the idea of Ehrenberg, 
that a foot-like process can be protruded from this spot, is uncon- 
firmed; indeed, it is pretty weir^fecertained, that the supposed openings 
are not actually such, but either depressions or elevations, more 
probably the former, of the surface of the lorica. 

The development of Cocconeis by self-fission, considered doubtful 
by Ehrenberg, is spoken of as unquestionable by Kiitzing, who also 
describes the very smaR specimens as occurring together in great 
number, and enveloped in a gelatinous substance. Moreover, little 
doubt remains, from the researches of Mr. Thwaites and others, that 
Cocconeis, like its allied genera Cocconema and Eunotia, is propagated 
by the process of conjugation. The members of this genus are met 
with abundantly, both in fresh and salt water, floating about in an 
isolated manner, or more commonly still, parasitic on Algse, such as 
Cludoplwra, Callithamnium, = Polysiplionia, Conferva, &c. They 
occur also in the fossil state. The marine species are most beautifully 
sculptured, whilst the fresh water are smooth. 

Cocconeis scutellwn. — Elliptic, convex on one sui'faccj with trans- 



Mzviculacea.'} infusorial animalcules. 333 

verse, finely punctate, and cnrvecl strife; common on sea- weed, — as 
Ceramium. Fossil at Cassel, North America, &c. Length 1-11 50th. 
to l-240th. (fig. 162, 163.) 

CoccoNEis tmdulata. — Similar to the preceding, except in being 
sculptm-ed with very delicate, concentric, undulating lines, instead of 
transverse striaj. Length 1- 432nd. On sea- weed, Baltic. 

C. placentuh. — Plane, elliptic, smooth, Avith an abrupt margin. 
Length 1-1 440th. In fresh water, upon Yaucheria and Lemna. 

C. pcdiculus. — Small, elliptic or oval, convex and smooth ; the disc 
presenting a vciy fine longitudinal line, and the margin thi-ee lines. 
Length 1 -2200th. to 1 -960th. Common on fresh water Algae. 

C. (?) Finnka. — Ovate, oblong, slightly convex; smooth exter- 
nally, but stiiated within. Length l-570th. Fossil; Finland, 
Mexico, &c. 

Var. (Jb.) — Larger, very elliptic, elongate, three to foar times 
longer than broad. Length l-360th. Alive at the mouth of the 
Elbe, and Antwerp. (P. 15, f. 41.) 

C. Americ-ana Smooth, with the habit of C. Iicxicana, but striae 

obsolete. Mexico. 

C. borealis. — Smaller, much elongated and elliptic, transversely 
striated. = C. Islandica of Mexico. ^Iceland. 

C concentrica. — Small, broadly elliptic, ends widely rounded, and 
Avith four concentiic longitudinal lines on each side. Mexico. 

C. decussata. — Larger, broadly elliptic ; rough, decussated by 
rows of puncta, fapicuU ?J Cuba. 

C. elongata. — Smaller, smooth, ovate-elliptic, plane. Approaches 
C. Plauniida, but is smaller; it, however, may be but a variety. 
Massachusetts. 

C. fasciata. — Elliptic, larger, linear, with two longitudinal lines, 
and a smooth transverse band at its middle. Peru. 

C. Leptoceros. = Rhaphoneis Leptoceros. — Still larger ; has the 
habit of C. Ampldeeros, but its beaks much longer. 

C. longa. — Small, smooth, linear, rounded on each side. Iceland. 

C. Mexicana. — Rhomboid, punctate -striate, small ; ends obtuse, 
and rather prolonged. It is small and more obtuse than C. Rhomlus. 
Mexico. (P. 15, f. 48, «. b.) 



33-1 DESCRIPTION OF {I*oly(jastru-a. 

CoccoifEis prceiexta. — Small, elliptic, -with six longitudinal lines 
on each side of the centre ; and a dilated, smooth, areolar margin. 

C. punctata. — Veiy small, elliptic, with eight longitudinal lines 
each side of the median line. Mexico. 

C. (?) Crux. — Smooth, elHptic, slender, with a transverse linear 
umbilicus. Diameter l-1632nd Bermuda., 

C. rhomhea. — Of the form of a rhombus, with generally thi'ee 
longitudinal lines each side the centre. Length l-1200th. Alive 
at Niagara. It is very like C. Mexicana and C. Americana. 

C. AmpMceros — Eoughly striated ; navicular on the side ; each 
extremity suddenly attenuate and much prolonged (rostrate), 
narrowly linear on the back. Length 1-5 76th. Marine at the 
mouth of the Elbe. See Rhaplioneis Amjylnceros. 

C. //;«5«^«.— -Sub-orbicular, elliptic, with a porous wide margin ? 
disc with twelve longitudinal fine lines passing along its middle ; 
ends widely roimded. Length l-576th. Salzberg. 

C. (?) Navicida — Striated ; navicular on the sides ; narrowly 
linear on the back, with an indistinct central longitudinal J"sulcus 
(furrow.) Length l-864th. Marine. The Elbe; parasitic on 
Bacillaria paradoxa. 

C. Rliombus = Ehaplioneis Ull^^his. 

C. (?) margaritlfera. — Broadly ovate ; each end subacute, with 
transverse granular striae, like rows of pearls. It is closely allied to 
C. Mexicana, but rather larger and not curved. Bosphorus. 

C. scutum. — Found by Ehrenberg, in. earth from jSTew Holland. 

C. disciformis. — From the same locality. 

C. no/vicularis. — From the same locality. 

C. gemynata. — Found in the chalk marl of ^gina. 

C. occanica (Ehi'.) — Ellij)tic, suborbicular, convex, marked by 
simple curved and concentric lines ; not undulated ; transverse striae 
none. Length l-1150th. In sea water, Callao, Peru. (P. 15. f. 
42.) Kiitzing describes this species as roimded, with numerous 
very delicately punctate longitudinal lines. Length 1 -624th. Baltic, 
North Sea, Peru, &c. He considers it identical with Ehrenberg's 
species ; but it has curved and concenti'ic lines. 

C. pt/ffinwa (Kiitz.) — Minute, elliptic, very smooth, sun'ounded by 



Naoiculacea.] infusorial animalcules. 335. 

a creuulate border. Baltic and North Sea, ou Ceramicse. Length 
l-2640th. 

CoccoNEis molesta (Kiitz.) — Minute, elliptic-oblong, very closely 
ag-gregated, cxuite smooth, -without a border (linibus.) On Callitham- 
nion, Venice. Length 1-1 800th to 1-1 680th. 

C. salina. — Narrower than C. FeiUculus, punctated, and very deli- 
cately transversely striped near the margin. Probably is but a 
variet}-~of C. Pedicuhts. 

C. 2»(i'iila. — Minute, quite smooth, slightly curved, elliptic-oblong; 
the border ^^ithout any longitudinal Unes. Length l-1560th. 
Nordhauscn. 

C. depressa. — Minute, much depressed, elliptic ; near the margin 
punctate. Striate. Length 1-1 800th. On Cladophora. 

C. nigricans. — NiuTowly elliptic ; densely aggregated ; margin 
(limb) rather wide, entire, of a brownish-black colour, trans- 
versely striated; thirteen to foiu'teen striae in 1- 1200th. Length 
1- 1200th. On Conferva at Trieste. 

Var fh.J C. denudata. — Limb wanting, also the transverse dotted 
stri®. Length 1-1 320th. 

C. ohhmja. — Oblong-elliptic, apices rather acute, with longitudinal 
lines. Length 1 -320th. On Confer-"^. North Sea and Indian Ocean. 
C. consociata. — Broadly elliptic ; disc mostly "with radiating punc- 
tate stiise, thirteen on each side, with a central longitudinal hyaline 
line. Length 1-1 320th. On Conferva. Baltic. 

C. aggregata. — Oblong-elliptic, surrounded by a broad margin, 
which is lacerato-crenulate ; disc, near the margin, with finely- 
dotted rays ; and in the middle with dotted fine lines. Length 
1 - 1 440th. In Baltic and North Sea. 

C. nidulana. — Elliptic-oblong, very smooth; on the side oblong- 
rectangular. Length l-1320th. Coast of Normandy. 

C. striata. — Of middling size; elliptic-oblong, transversely striated. 
Cuba, Mexico, United States. 

C. pinnularia. — Rounded eUiptic, the margin and disc (save the 
crenate longitudinal medium line) transversely stiiated. Florida 
coast. 

C. marginata. — Elliptic ; margin punctate (in older specimens with 



336 DESCRIPTION OF \^Folycjaslrica. 

radiating striae), and with longitudinal central lines. Length 
l-840th. On Marine Algae. Adi-iatic. 

CoccoKEis Adriatica. — Large, elliptic, with granular striae, trans- 
verse on the disc ; radiating on the margin. Length 1 -696th to 
1-4 80th. Trieste. 

C. Ifediterranea. — Size variahle, elliptic or elliptic -oblong ; disc 
regularly dotted ; dots disposed both La transverse and in longitudinal 
lines. Length 1 -840th to 1 -552nd. I^aples, Genoa. 

C. Peruviana. — Elliptic ; disc regularly punctate, with large 
puncta in fours, disposed at greater distances. Length l-840th. 

Genus Coscinodiscxjs, (Ehi\) — Individuals solitary ; lorica bivalve, 
discoid ; surface of disc cellular, with or without a central spot or 
umbilicus ; without processes or defined margin. 

Coscinodiscus gives name to a family Coscinodiscece, see page 308, 
which, together with the genus named, comprises Adinocyclm and 
Actinoptychus ; it is a member of Ktitzing's tribe of areolate (cellular) 
DiatomecB ; so called from the cellular character of their valves. 

Coscinodiscus approaches GaJUonella (Melosira), but is distinguished 
by its cellular surface, and by not being concatenate. 

The members of this genus occur both in a living and fossil state, 
and are marine in their habitat. 

C. patina. — Large, with moderately-sized cells, disposed in con- 
centric circles. The cells decrease in size towards the circumference. 
Fossil in the chalk marl of Zante, and alive in sea water at 
Cuxhaven. The young and ^sdgorous specimens of live individuals 
are completely filled with yellow granules, whilst the older ones 
have an irregular yellow gTanular mass within them. Diameter 
l-8G0thto l-240th. 

C. radiatus. — Large, marked with moderately-sized cells, disposed 
in lines, radiating from the centre ; towards the margin the cells 
become smaller. A very abundant fossil in the chalk marl of Oran ; 
alive, in sea water, near Wismar and Cuxhaven. Diameter l-860th 
to 1 -240th. (P. 14, figs. 39, 40.) 

C. Argus. — Cellular ; cells larger at the centre than at the cir- 
cumference ; the order of the rays often interrupted. This is 



j^Kvicidacca.'] infcsoeial animaicules. 337 

probablj'^ only a variety of C. radiatas. Fossil in the clialk inaii of 
Caltanisetta and Oran, and living, in sea water near Cuxliaven. 
The cells of the discs, from Oran, vary very much in size. Tho 
granules are of a greenish coloiu- in the living forins, which are very 
rare. Diameter of fossil l-860th to l-290th ; living, l-580th. 

CosciNODiscus ecccntricus. — Cells small, disposed in eccentric curved 
lines Found fossil in the chalk marl of Oran, in wliich con- 
dition, however, it is rare ; but alive, it is met Avith abundantly 
in sea water near Cuxhaven and Yera Cruz. Locomotion not yet 
satisfactorily observed. Diameter 1 -860th to 1 -430th. 

C. lineatus. — Cells small, disposed in a series of straight and parel- 
lel lines. Fossil in the chalk marl of Caltanisetta ; alive at Cuxhaven. 
The cells in this species form parallel lines in whatever direction 
tliey may be viewed. In large and well-preserved fossil specimens 
as many as twent^'-five openings were seen near the circumference. 
AVithin the live forms, sometimes numerous yellow vesicles are seen, 
as in GalUonella. Diameter of fossil 1-11 oOth to 1 -480th; living, 
l-1150th to l-860th. 

C. minor. — Small ; cells small, scattered. Fossil in the chalk 
marl of Caltanisetta, Oran, and Zante ; and alive in sea water near 
Cuxhaven. Diameter 1 -11 50th. ^' 

C. Oculus-Iridis. — Cells rather large, radiant ; smaller near the 
centre and circumference. From five to nine large cells at the 
centre form a sort of star. Fossil in the chalk marl of Greece, and 
alive in sea water near Cuxhaven. This large species is curiously 
marked with coloured rings, which are apparently caused by the 
peculiar arrangement of the cells. This species differs from C. 
centralis in having larger cells ; and from C. asteromphalus by its 
surface being unveiled, and its cells rather smaller. Diameter 
1- 240th. 

C. limlatus. — Centre cells largest, not radiant ; margin with linear 
rays, forming a striated rim (limbus). Diameter l-576th. Fossil in 
Greek marl. The larger cells seven in 1-1 200th. 

C. concavus. — Each valve very concave ; cells large, of equal size ; 
four and a half in 1-1 200th ; not radiating. An African variety has 
seven to nine cells in 1- 1200th. Richmond, Vii-ginia. 



338 DESCEIPTION OF [Poli/gastnca. 

CoscmoDiscvs Jfdvicans. — Small, with very smaU nou-radiaut cells, 
yellow by transmitted, but white by reflected light. Peru and St. 
Domingo. 

C. gigas. — Veiy large ; cells hexagonal radiant ; central ones the 
smallest ; marginal very large ; rim striated. It is figured by Dr. 
Bailey. Cells five to six in 1 -1200th near the margin. Fossil, 
Yii-ginia. Alive at Ciixhaven. 

C. marginatus. — Cells of nearly uniform size, imperfectly radiant in 
curved lines ; the rim furnished with radiating lines of smaller cells. 
Cells nine to ten in l-1200th. Fossil in Vu-giuia. Alive at Cuxhaven. 

C. radiohtus. — Cells very small, equal, and radiant. Eighteen in 
1-1 200th. Peru, Cuba, and Yirginia. 

C. suit His. — Similar to the last, but "^ath twenty-four cells in 
1-1 200th; and of uniform size. 

C. apiculattis. — Cells slightly prominent and apiculate (pointed), 
rendering the surface rough : disposed in the manner of rays ; ten 
in 1-1 200th. Diameter 1 -324th. Vii'ginia. Has a general resem- 
blance to Fyxidimda gemmifera. 

C. aster omphalus. — Cells larger, seven to eight in l-1200th, 
rather prominent, and in rays, decreasing in size towards the 
margin ; a eenti-al stellate umbilj^^is ; surface appearing as if over- 
spread by a finely dotted membrane (veil.) Diameter 1 -324th. 
Yirginia. 

C. centralis. — Differs by its smaller, equal, and radiating cells, 
which are twelve in 1-1 200th; sui'face also not veiled. Has a 
similar central stellate umbilicus. Yirginia and Sicily. 

C. velatus. — Differs from the preceding by wanting the centi-al 
stellate umbilicus. Cells angular ; surface as if covered with a 
gi-anular veil. Diameter 1 -492nd. 

C fimbriatus. — Cells small, thirteen to foiu-teen in l-1200th; im- 
perfectly radiant and unequal ; near the margin occui-ring in lines, 
and of smaller size. Diameter 1 -324th. Caltanisetta, Sicily. 

C. perforatus. — Cells small, evidently radiant, thirteen in l-1200th; 
with a smooth central umbilicus, looking like a perforation ; margin 
finely rayed. Diameter 1 -348th. Yirgioia. Allied to C.7?wJr?^^ws, 
which, however, has not the smooth, central umbilicus. 



Navicuhtcea.'] infusorial animalcules. 339 

CoscniTODiscus punciafifs. — Cells very small, radiating ; tweuty-lbiir 
to twentj'-six in l-1200th ; loosely disposed at the centre, but dense 
towards the margin, which presents a broad, ^'cllo-wish-whitc rim. 
Diameter 1 -348th. Yiigiuia. 

C. clisciger. — Differs from C. perforatus by its ii-regnlarly circiilar, 
not smooth, and larger umbilicus ; cells very small, dotted, and very 
dense, indistinctly radiant; above thirty in l-1200th. Yii'ginia. 
Diameter 1 -480th. 

C. (?) pohjstigma. — Differs from C. radiolatus by its much larger 
radiant cells, fourteen in 1- 1200th ; rays converging, so as to form 
two indistinct whorls (zones), perforated, and disposed side by side. 
Diameter l-360th. If a species ofAtiliscus} (p. 321) In the North Sea. 

C. hetcro2)orus. — Cells hexangular, smaller at the margin, and ten 
in 1 -1200th; intermediate ones five to six in l-1200th. Diameter 
1 -360th. Bermuda. 

C. ompludantlm^. — Large, cells radiating, those of the margin 
smaller, seven to eight in l-1200th, whilst at the middle there are 
but six in l-1200th; centre occupied hj a rose-Hke stellate umbili- 
cus, formed by seven to eight larger oblong cells. Diameter 1.96th. 
Bermuda. 

C. Apollinis. — Surface covered w^ very dense pimctiform tubercles, 
seventeen in 1-1 200th, of equal size, and in rows radiating towards 
the margin. Diameter 1 -432nd. 

It differs from C. Lima, which it most nearly resembles, by the 
greater number and denseness of its raj's, and by its larger size. 

C. (?) acthiochilus. — Centi-e of the disc occupied by punctate 
tubercles, densely radiated with an umbilicus; margin (rim) wide; 
irregularly dotted radiating lines (costte) of the margin, smooth, and 
fifty-four in number. Diameter l-408th. Not unlikely constitutuig 
a genus by itself. 

C. cingulatus. — Disc with pimctate tubercles, twenty-six in l-1200th; 
dense, indistinctly radiant ; a small clear umbilicus ; margin with a 
strong annular band, capable of being detached. Diameter 1 -552nd. 
Stands between C. suUilis and C. gemmifer. 

C. (?) Gemmifer. — Disc with strong tubercles, loosely and elegantly 
radiant, ten in l-1200th; a clear umbilicus. Diameter l-456th. 



340 DESCRIPTION OF {Volygasirlca 

Yery like to Pyxidiciila gemmifer, of Virginia, but a larger and more 
depressed fomi. It also approaches C. cingulatus. 

Coscr^oDiscrs Luna. — Disc covered with dense, punctate tubercles, 
equal, radiant, but becoming, tov^ards the margin, loose and imequal. 
It is nearest to C. ApoUinis. 

C. granulatus. — Small ; cells very small, giving a gi'anular appear- 
ance to the disc ; dense, and disposed in rows ; eighteen to twenty- 
one in 1-1 152nd. Diameter l-552nd. Fossil, Yirginia. 

C. spinulosus Testule flattened, surface finely porous ; margins 

of pores spinous; spines and pores about t^velve in 1-1 152nd. 
Diameter l-576th. Fossil, Patagonia. 

C. mtmitus (Kiitz.)— Margin with dotted rays ; disc nearly smooth. 
Diameter 1-1 41 6th. 

C. minor. — Margin smooth ; disc irregularly and densely punctato- 
celhxlar. Diameter 1-1 150th to l-576th. Fossil in chalk marl, 
Greece, Sicily, Peru, &c. Alive, Cuxhaven, 

C. striatus (Kiitz.) — Margin striated with radiating linos; disc 
cellular; cells of centre without order. Diameter 1 -456th. Cuxhaven. 

C. cinctus. — The striae of the external rim radiating, but broken at 
their middle ; central cells closely aggregated, those around loosely 
so. Diameter 1 -324th. Alive, ^^haven. Fossil, Eichmond, Vir- 
ginia. 

C. cruciatus = Pi/xidicula cmciata and Pgxidicula Selhnica (Ehr.) 
— Cells hexagonal, arranged in straight, parallel lines, with a smooth 
annular rim. 

Genus Ceaspedodiscts.— Shell composed of two equal orbicular 
valves, not in chains ; surface cellular, cells having a radiating 
arrangement ; otherwise not radiated nor divided by septa, but with 
a sculptured tumid margin, of a different structure, and separable. 

Has the habit of Coscinodiscus, with an elegantly sculptured 
margin (rim.) It differs from Coscinodiscus liiiilatus and similar 
foi-ms, by its margin not becoming gradually lost in the disc, nor 
being a mere boundary to it of the same structure ; but, on the con- 
trary, separated from it by a distinct farrow, and having a different 
structure. This border is cither developed at the first, or the being 
exists primarily as a CcDiipylodiscas, the rim being a gradual 
production. 



Naviculacea.'] infusorial ANiMALcrLES. 3U 

Pijxidicula Coscinodiscus, of Virginia, -would seem to be a member 
of this genus. 

CKAsrEDODiscus elfigatis. — Disc large, central cells radiant, seven in 
l-1200th; five to six larger oblong ones constitute a centi'al umbilicus; 
margin tumid, l-llo2nd wide, with larger obliquely quadrate cells, 
six in l-1200th. Diameter l-132nd. Bermuda (P. 14, f. 38.) 

C. Coscinodiscus = Pijxidicula Coscinodiscus. — Central cells of the 
disc small, decreasing towards the centre, seventeen to eighteen in 
1-1 200th; no umbilical star; cells of the margin larger, unequal, 
hexagonal, about ten to eleven in 1-1 200th. Diameter l-39Gth. 
Richmond, Virginia. The rim of this species is wider than that of 
the preceding. 

Genus Cxclotella (Kiitz.) — Individuals solitaiy or binate, disci- 
form, orbicular ; the primary side distinct, forming a ring ; the 
secondarj'- plane. Lorica bivalve, valves plane, orbicular, conjoined 
by an interstitial ring. 

Sect. I. Individuals included in an amorphous gelatinous suhstance, 
(Discoplea, Ehr.) 

C. operculata = Discoplea Kutzingii (Ehr.) = Pyxidicula operculata. 
Secondary sides dotted on the margin. Diameter l-1020th. Common 
in fresh water. ■** 

C. Meneghiniana. — Secondary sides striated on the margin. 
Diameter l-1440th. Berlin. 

Sect. II. Individuals adnate (free.) 

C. Scotica. — Small, quite smooth. Diameter of the plane disc 
l-960th. On Conferva, Coast of Scotland (P. 17, f. 17.) 

C. ligustica. — Of middling size, quite smooth, adnate or free. 
Diameter of plane disc 1 -720th to 1 -51 6 th. On filiform AlgaB, Genoa. 

C. maxima. — Large, minutely pimctate, adnate. Diameter of the 
nearly plane disc l-300th to l-126th. On Polysiphonia, Coast of 
Peru, Chili. 

C. (?) mimitula. — Small, with radiating and flexuosc striae on the 
secondary side. Diameter 1-1 200th. Eossil in Lunebcrg. It may 
be but a separated segment of Melosira. 

C. (?) Rotula — Rather small; secondary side with radiating striae, 
and a dotted centi'e ; one side convex, the other concave. Diameter of 



312 DESCRIPTION OF '^JPolyrjasinca, 

disc l-480tli. Fossil in the Elbe deposits. Probably a segment of 
Mehsim arenaria. 

Cyclotella (t) Kutztnffiana (Tbwaites.) — Frustules (cells, on primary 
side sigmoid, flexnose ; on secondary side with radiating striae. The 
frustules of this species are short, and have an apparent sigmoid 
curvature, which is due to each of their striated, discifonn ends, 
having a prominence on one side of its centi'e, and a dej)ression on 
the other, and the opposite end of the frustule having a depression 
and prominence corresponding to these. The sporangia are developed 
much in the same way as in Melosira. This species is closely allied 
to C. (?) minutula (Kiitz.), but differs in the curvatures apparent 
in the ifrustulcs. Itoccui's in brackish water, near Bristol. (Ann. N. 
H. 1848, p. 169.) 

Genus Cymatopletjea (Smith). — Yalves undulated, margins not 
produced into alae. Frustules free, solitary, or, when undergoing 
self- division, in pairs. 

It has the habit of SurireJla, but the undulated siirface of the 
valves seems to indicate a peculiarity of structure sufiicient to con- 
stitute a generic difference, and the absence of ala3 and costse implies 
a further diversity in the internaL-haracter, which cannot be regarded 
as unimportant, (Ann. Nat. HisiT^p. 12. 1851.) 

C. solea = Surirelh lihrilis (Ehr. P. 18, f. 9, a lateral view.) 

C. elJiptica = Surirelh elJiptica (Kiitz.) — Frustules on front view 
oblong, linear ; on side view broadly elliptical, surface of the valves 
with about four imdulations, obsciu-ely striated. Length l-350tli 
to 1 •200th. Breadth about half the length. Fossil and alive in 
slow streams or ponds with OsciUatoriece (P. 18, f. 7, 8.) It is veiy 
variable in size, the fossil specimens being usually twice as large as 
the recent frustules. Both extremities of the valves are somewhat 
pointed. 

C. Hihernica. — Frustules on side view orbicular, with prominent, 
somewhat pointed extremities; surface of valve with about three 
undulations obscurely striated. Length l-370th to l-220th. Breadth 
two-thirds the length. Eiver Bann, Ireland. 

Genus Cymbella (Kiitz.) — Individuals solitary or geminate, free 
(neither adnato nor included), unequally curved ; one primary side, 



Naviculacca.'] infusorial ANiiiAi.cri.Es. 3 If? 

the internal and ventral, narrower than the other, the cxteiual or 
dorsal ; secondaiy sides eqnal, transversely striated, the median 
apertures of the margins approximate. 

This genus includes species distributed in the genera Syncyclia, 
Cocconema, Navicula, and Pinnularia, of Ehrenberg's system. 

Its free unattached forms have an affinity, some with Epithemia, 
others with Navimla and Ampliora, but differ from those genera by 
their median ventral aperture, and by their unequal dorsal aspect. 
Cymhella has also an affinity with the genera Gomphonema, Encyo' 
nema, and Schizoncma, fi'om which also it may be distinguished by 
the characters named. 

Cymbella Ehrenhergii r= N'aviada inequalis (Ehr.) — Large, un- 
equally and broadly lanceolate; apices rather produced, and somewhat 
obtuse; transverse striae pimctate, twelve in l-1200th (P. 3, f. 154.) 
Length 1-21 6th. Berlin. Fossil, San Eiore. 

C. heteropleuia = Pinnularia heteroplcura (Ehr.) 

C. cuqmlata. — Small, rather wide in proportion ; apices produced 
and slightly acute ; transverse striae fine, sixteen to eighteen in 
l-1200th. Length l-576th. Fossil, Luncberg, 

C. obtusiuscula. — Small, elliptic, lanceolate ; apices not produced, 
rather obtuse; transverse striae finef eighteen to twenty in l-1200th. 
Length 1 -600th. 

C. yastroides. — Large, sublimate, unequal, thickened at the middle, 
but tapering towards the obtuse ends ; transverse striae granular, 
eleven to twelve in 1-1200. Length l-288th to l-216th (P. 17, 
f. 18, 19, 20.) Fresh water, Germany. 

Yar. fh.j — Apices broadly truncate. 

C. maculata = Cocconema lunula (Ehr.) — Small, lunate, tapering 
at each end ; obtuse ; primary side elliptic, truncate ; transverse 
striae, twelve to thirteen in 1-1 200th. Fresh water, America. 

C. Helvetica. — Large, slender, elongate ; ventricose at the middle, 
but tapering towards the rather obtuse extremities ; oblong on the 
primary side, dilated at the middle, and tnincate at each end ; ti'ans- 
verse striae fine, very beautifully granular ; thirteen to fourteen in 
l-1200th. Length l-264th to l-240th. Thun, Switzerland (P. 17, 
f. 24 to 28.) 

C. gracilis = Cocconema gracile (Ehr.) — Small, slender, lunate ; 



31i DESCRIPTION OF {^PolygasincA- 

attenuated at eacli end, apices somewliat acute ; primary side larger, 
linear- oblong, and ends rounded, ti'uncate ; transverse strias very 
slender, seventeen in 1-1 200th. Length l-840tli to 1 -600th. AtThun. 

Cymbella Leptoceros = Cocconema Leptoceros (Ehi-.) — Minute ; 
acute at the ends ; inflated at the centre ; primary side large, oblong- 
elliptic, rounded at the ends; striie seventeen in 1-1 200th. Falaise and 
America. 

C. affinu = Cocconema Fmidium (Ehr.) — Minute, somewhat obtuse 
at each end ; dorsum more prominent, with large terminal apertures, 
primary side larger, oblong-elliptic ; transverse stria3 distinct ; nine- 
teen in 1-1 200th. Alive, Falaise, Schleswig. Fossil, America. 

C. ventricosa. — Minute, rather obtuse at each end, dorsum promi- 
nent, rounded; venter plane, terminal apertures distinct, large, 
hyaline; primaiy side oblong, truncate; striae indistinct. Length 
1-lOOOth. Fresh water. 

C. excisa. — Eather small, dorsum prominent, convex ; venter with 
a central notch ; apices produced, slightly recurved, obtuse ; trans- 
verse striae sixteen in l-1200th. Length l-840th. On Oscillatoria, 
Trieste. 

C. (?) Peclicidiis. — Very smoo^^. small, lunate; dorsum convex; 
venter rather concave; ends sc*liewhat acute. The other aspe-ct 
elliptic truncate. Common. Parasitic on Conferva. 

C. Q)flexella. — Small, smooth, secondary side elliptic, subsigmoid, 
apices rather produced,but obtuse ; on the other aspect curved, convex ; 
venter concave, notched (excised), ends truncate. Length 1 -650th. 
At Thun, Switzerland. This species probably corresponds to Navi- 
cula Semen, (Elir.) 

Genus DENTicELLA(Ehr.) — Generic characters unknown. 

This genus is not recognised by Kiitzing, who retains its species 
mostly in Odontella, with which they were originally classed by 
Agardh. Its affinities are with Idhmia, Biddulplna, and Zygoceros. 

D. aiirita. 
D. fragilaria. 

D. gracilis. — Finely striated transversely ; width greater than the 
length ; laterally constricted nearly to the central band ; chain 
1-1 152nd in width. The length of D. aurita exceeds the breadth, 
but both are compressed, and tridentate on the sides, with a dorsal 



JVavicidacea^] infusorial animalcules. 34S 

and ventral hook in the middle of the sides, and two apertures at 
the angles. 

Denticella (?) tumida. — Testules turgid (subglobose) without lobes 
or septa ; surface minutely dotted ; with two long exserted (projecting) 
tubules and seta) on each side. Diameter 1 -960th. Bermuda. 

D. lavis. — Has the habit of D. aurita, but with a smooth triden^ 
tate testa. Diameter 1-4 32nd. Antarctic Sea. 

D. Biddulphia. — Sculptured. In habit and surface resembles Bid^ 
diilphia piilcliella, but has long setae disposed midway between the 
contiguous halves. It has three cells, and two septa to each lateral 
segment. (P. 13, f. 48.) Cuba, Peru. 

D. Rhombus. — Surface, with very minutely dotted lines : resem- 
bles Zygoceros Rhomhus, but is provided on each side, at the middle, 
with a sharp hook. Diameter 1-3 12th. Petersburg, Virginia. 

The band (zone) on the dorsum, like as in Zygoceros, is not smooth, 
but adorned with rows of minute dots (puncta.) 

D. tridentata. — ^Has the habit of Biddulphia tridentata, but the 
di.z\\\.Gioi a. Denticella. Diameter l-480th. Yirginia and Maryland. 

D. (?) pohjmera. — Testules very broad, with ten to twelve septa 
and lobes ; siu-face granular ; six granules on the anterior surface of 
tht' central lobe, disposed in the for^^'/f a star ; spiny denticles on the 
sides, not in the median line ; tubules of the apertures projecting 
some distance. Length 1-1 32nd. Bermuda. 

Genus Denticula, (Kiitz.) — Free, solitary, or binate; linear- 
oblong on the primary side ; the secondaiy transversely striated 
or costate ; strire very distinct. 

This genus, named by Kiitzing, is placed in the family Fragila/riea, 
Its members known to Ehrenberg, were described by him, some 
among Fragilaria, others with Bacillaria, (Biatoma). Benticula 
approaches Surirella and Navicula. 

D. tenuis. — Narrowly linear, margin finely punctate ; secondary 
side minutely striated, narrowly lanceolate; transverse strite ten 
to eleven in l-1200th. Length l-1080th. Among Conferva at 
Nordhauscn. 

D. frigida. — Oblong, small, margin finely striated ; secondary side 
linear lanceolate; transverse striae eleven to twelve in l-1200tll/ 
Length 1-1 200th, Cold Alpine streams, Thun, Switzerland. 

A A 



316 DESCEIPTION OF {Tolygastrica. 

De>"ticella thermdis. — Oblong or subtrapczoid, margin beautifuQy 
dotted ; secondary side lanceolate ; transverse striae seven to eight in 
l-1200th. Length l-660th. Hot baths of Abano. 

D. elcgans.— Oblong, with obtuse angles, rather dilated at the 
centre ; naargin with minute prominences ; secondary side linear 
lanceolate; transverse striae six in l-1200th. Length 1 -660th. 
Nordhausen. (P. 16, f. 4.) 

D. ohtusa. — Oblong, large, margin striated ; secondary side lanceo- 
late; ends obtuse; transverse striae eleven in l-1200th. Length 
1 -336th. Sweden, Norway, Jutland. 

D. constrida = Navicula (?) constrida, (Ehr.) — Oblong, large, mar- 
gin dentate ; apices dilated, rounded ; secondary side transversely 
ribbed, oblong, equal ; each end rounded and truncate ; three to 
four costae in l-1200th. Length l-216th. Berlin. (P. 16, f. 3.) 

D. undulata = Navicula (?) undulata (Ehr.) — Yery large, oblong, 
rectangular ; margin dentate ; remarkable by a pair of dotted longi- 
tudinal flexuose lines ; secondary side elliptic, apices rounded ; 
transverse costae four in l-1200th. Length l-144th. Berlin. (P. 3. 
f. 149.) 

Genus LESMOGOxrcTM:, (Ehr.)— (Characters unknown. 
D. Guianense occurs fossil, a^^iin meteoric dust. From Ehrenberg's 
figures (P. 24. fig. 13), of this species, Besmogonium would seem 
to belong to the family Naviculece ; it appears, however, to possess 
no foramina. 

Genus DiADESMis, (Kiitz.) — Individuals navicula-shaped, conjoined 
so as to form elongated (biconvex) bands, with one median aperture 
and two terminal ones, distinct. It is a member of Klitzing's family 
Naviculece. Ehrenberg has described two of the species with 
Talellaria, and a third with Navicula. It closely resembles Fragil- 
laria, from which it differs in its fnistules having a median 
umbilicus. 

D. confervacea. — Smooth ; length of each individual frustule, i. e., 
the width, when conjoined in a filament, double that of its shorter 
diameter ; lateral jimction surfaces lanceolate and acuminate at each 
end. Length 1 -960th. Among Conferva, Trinidad. (P. 17. f.. 32, 33.) 
D. Icevis = Tabellaria Iccvis (Ehr.) — Smooth ; length three to four 
times the breadth. Chili. 



If'avicuiacea.] infusortai, animalcules. 347 

DiADESMis sculpta ^i:: TahcUaria sculpta (Ehr.) — Margin striated. 
ChiU. 

D. (?) Bacillmn = Kavicula BaciUum (Ehr.) — Segments striated, 
linear- oblong, rounded at each end, central aperture large, oblong. 
FossU. 

Genus Diatoma (Ag.) — Individuals linear, quadrangular, symme- 
trical ; at first conjoined iia bands, but ultimately separated to such 
an extent, that they are connected only by a more or less distinct, 
jelly-like link, (isthnusj extending between their angles, — generally 
the alternate ones. The filaments are flat or compressed. (Kiitz.) 

Biaioma differs from TaheUaria, (see that genus) Grammatophora^ 
and Bhaldonema, by its frustules wanting longitudiaal bands f stripes J ; 
and from the two first also, by the absence of a central aperture. 
From Fragilaria it is distinguished by the angular and zig-zag con- 
catenation of the finistulcs. Kiitzing says its filaments are often 
attached. He makes it a member of the family Frcujilariece. 

Ehrenberg describes the species of Biatoma, (Kiitz.) some with 
Fragilaria, others with Bacillaria. The latter is, however, nearly 
equivalent with Biatoma, (Ag. ) as understood hy Kiitzing; 
to convey his views, at the risk of repetition, the characters of 
Biatoma presented by that obsciwer^re given. It may be observed, 
that Kiitzing admits a genus BaciUarin, which is represented by one 
species, Bacillaria paradoxa ; he places it in his family Surirelleee. 
The reason he assigns for instituting this genus, is, that in Bacillaria, 
the striae (seen in an end view) are interrupted in the middle by a 
clear longitudinal band, which is not the case in Biatoma, 

The genus Biatoma of Mr. Ealfs, would appear to correspond with 
Bacillaria of Ehrenberg, and with the genera Biatoma and Ba- 
cillaria, of Kiitzing. Mr. Ealfs enumerates the following characters 
and marks of distinction between it and allied forms. Filaments flat or 
compressed, free frustules quadrangular, partially separating, and co- 
hering by the angles, generally by the alternate ones. This genus ia 
distinguished from Fxilaria, Striatella, Achnantkes, and Isthmia, by 
its unattached filaments ; from Biddulphia by the angles not being 
produced, and from Fragilaria by the connection of the frustules by 
their angles, in a zig-zag chain. 

Sect. I. Forms quite smooth, 

A A 2 



348 BESCEiPTioN OF [Poli/ffosirtca. 

DiATOMA j'^ff^/wrt!?^. — Segments laterally acutely lanceolate, accord- 
ing to Kiitzing it = Bacillaria seriata, B. Ftolomoei, and B. jlocculosa 
(Ehr.) Length l-720tli. 

D. vitreum. — Filaments attached by a very delicate stalk, and 
made up of few segments ; segments miuute, oblong, glass-like ; 
■ftath a longitudinal row of punctiform spaces. It is very closely 
allied to D. ininimum, Ralfs. Length 1 -1320th. On Algae in the 
Acb'iatic. 

D. hyalmum. — Segments larger, elongated, very slightly attenuate 
at each end ; peculiarly hyaline ; lateral aspect lanceolate, rather 
obtuse; with golden yellow interspaces. Length l-336th. Adriatic. 

Sect. II. Forms striated. 

D. mdgare. — Filaments long, attached by an almost invisible 
stalk ; segments rectangular, convex, striatedo n the margin ; punctate 
at each end ; three to four times longer than broad. It = Ba- 
cillaria jlocculosa and B. vulgaris (Ehr.) (P. 3, f. 168.) Length 
1 -420th. Pools and streams. Common. 

D. mesodon. — Segments oblong, with a few central dentations, 
laterally ventricose, lanceolate, with three to four transverse striae 
at the middle. 

Var. {h.) — Segments quadralS*!^ 

Var. {c.) cuneatum. — Segments cuneiform. It = Bacillaria cuneata 
(Ehr.) (P. 3, f. 170.) 

D. tenue. — Attached, stalk very indistinct; joints laterally 
lanceolate, with transverse strisD ; twelve in l-1200th. The form 
and size of the segments vary. 

Var. {a.) moniliforme. — Joints quadrate. 

Var. {b.) infer medium. — Diameter of joints twice the length. 

Var. (c.) cuneatum. — Segments cuneate. 

Var. {d.) normale. — Joints elongate, slender. 

Var. {e.) — Segments obliquely united. = Bacilla/ria pectinalis (Ehr.) 
Length 1 -660th. 

D. mesoleptum. — Attached, stalk obsolete ; segments rather con- 
tracted at the centre, laterally lanceolate ; transverse striae ten to 
eleven in l-1200th. Length l-650th. Freshwater. 

D. elongatum: — Attached, stalk obsolete ; segments very slender, 
rather narrower at the middle ; laterally linear, tumid, and capitate 



Naviculacea.'} infusoeial animalcules. 349 

at each end, cormected in a chain by a short fililbrm isthmus ; strioc 
seven in l-1200th. Freshwater. Length l-288th. This species is 
described by Mr. Ealfs, thus, — " Frustules plane, several times longer 
than broad; fi'ont suii'ace with the ends dilated." 

DiATOMA. Ehrenhergiu = Bacillaria elongata (Ehr.) — Attached, 
stalk minute ; segments strong, rather contracted at the centre ; 
laterally dilated at the middle, and contracted near the capitate 
ends; concatenated by a distinct isthmus. Length 1 -456th. 
Germany. (P. 3, f. 169.) 

D. stellaris (Bailey.) — Frustules rectangular, many (eight) times 
longer than broad, usually in groups of five or six individuals, 
cohering by the adjacent (not alternate) angles, so as to produce 
stellate groups of minute frustules. Common from Rhode Island 
to Florida. 

Genus Dicladia. — Lorica bivalve, not concatenated ; imilocular ; 
valves unequal, one simple and tui'gid, the other two horned ; the 
comua sometimes branching. 

In form this genus approaches Rhizoselenia. In respect to its 
position in the family Bacillaria, Ehrenberg appends a note of 
interrogation. 

D. Capreohis. — Smooth, bifurcc^ at one end. Diameter 1 -960th. 
Virginia. 

D. (?) chtJirata. — Smooth, with intersecting lines, (latticed); 
remarkable by its rounded outline, and two unequal frontal horns. 
Diameter 1 -960th. Vii'ginia. 

D. attenuata. — Smooth, with two simple horns at one end, with 
some parallel, long, acute, and jointed corniculi (setae) about then- 
base, resembling antennce : the other end unknown. Antarctic Sea. 

D. bulbosa. — One end with two simple horns, with corniculi diverging 
at the base, but converging at the apex ; bulbous in the central part 
and rather sulcate (furrowed) ; the other end unknown. Diameter 
of a fi-agment of the one valve l-782nd. Antai-ctic Ocean. 

Genus Dicxyolampka (Ehr.) — Bivalve ; orbicular, not concatenate ; 
disc not perforated ; internal septa absent ; valves equal, cellular 
only at the centre, their margin radiated, but otherwise smooth. 

From these chai'acters this genus would seem to be closely allied 
to Codciiiodisciis and Orusjjcdodiscus ; to differ from the former by the 



350 DEscEiPTioN OF \JBolygasirica. 

external portion or margin of the disc not being cellular, and from 
the latter by the absence of a distinct margiaal figured zone 
or rim. 

DiCTYOLAMFEA &tella. — Characters unknown. 
- Genus Diploneis. — Vide Pinmdaria. 

Genus Discoplea (Ehr.) — Characters unknown. 
This genus has a close affinity with Pyxidicula; it is in part 
equivalent to Ci/cloteUa (Kutz.), (p. 341,) one of the two sections of 
which, in this author's system, distinguished by being included 
in a gelatinous mass or nidus, has, indeed, the term Discoplea 
applied to it. 

D. (?) grceca. = Coscinodiscus (?) grcemts (Kiitz.) Disciform, on 
plane sides, interruptedly striated in a radiating manner. Diameter 
l-864th. In Greek marl. 

D. Kutzingii. — Smaller, disciform ; radiant strise present only 
along the margin of the plane sides. 

D. dendroclmra. — Small, tumid in front ; margin of disc, and also 
the centre, smooth ; the latter, however, with a minutely striated 
ring siu-rounding it. The rays of the central coronula (circlet) about 
ten in number. Diameter 1- 1920th. Found on the roots of plants 
from the moimtains of Venezuela "* Habit of D. compla. 

D.(:)A7ne)'ica>ia. — Turgid, with the habit of a compressed Gallionella 
or Pyxidicula ; the dorsum with thi^e ti'ansverse keels ; the lateral 
disc dotted in the middle. Diameter 1-6 60th. Yirginia, Maryland. 
D. (?) Actinocyclus = Pyxidicula (? ) Actinocydus. 
D. (?) astrcea. — Large, flat ; lateral margin densely rayed ; centre 
dotted. Diameter l-636th. Kurdistan. It has the habit and 
size of GaJUoneUa vUrians, with the peculiar central granules ; but 
not being met with in chains, seems nearer Disco2)lca. 

D. (?o/«^^^^— Slender, tumid in front; a crown of striae on the side 
near the margin ; and a remarkable central agglomeration of granules. 
Habit of D. Americana, but smaller. 

D. denticulata Surface beset with a pecuKar, straight, and parallel 

row of small cells or granules, ten La 1-1 152nd; margin dentated. 
Diameter 1-6 72nd. Bermuda. In the character of its margin it 
resembles Gallionella sxdcata, bat by the cells of its disc approaches 
Coscimdiscua Uneatm. 



Naviculacea.] infusoeial animalcules. 351 

DiscoPLEA (?) undata — Sui-facc covered by minute granules in 
radiating series ; margin undulate, with fifteen sinuosities. Diameter 
l-576th. Bermuda. 

D. (?) Penuina.—^\ixh.cG of disc rayed ; five fine rays reaching as 
far as the centre. The thickness of the bivalve testule equals half 
its width. Has the habit of D. astrcea, and of Oallionella varians. 
Diameter 1 -600th. Found in the pumice from Arcquipa and 
Santiago, Peru. 

D. (?) Eota — Disc large, surface unequally papillose ; central 
papillae largest ; margin with fifty-two equal rays not attaining the 
centre; their intervals occupied with scattered papillse. Diiameter 
1-1 92nd. It approaches Actimptyclim dives, to which, along with the 
ensuing species, it may be perhaps united in a new genus. A gela- 
tinous envelope is not apparent ; and true septa are wanting. 

D. (?) Rotula. — Disc smaller than the preceding, covered with 
small scattered and equal papillae ; margin with twenty equal rays 
not reaching the centre. Diameter l-696th. Southern Ocean. 

D. (?) dives = AdinoptycJius dices =^ Cyclotclla dives (Kiitz.) — Is re- 
markable by the rows of papillae in the intervals of the rays, and 
the smaller ones at the centre. Diameter l-812th. 

D. (?) Coseinodiseus. — Small ; ^>?c irregularly but densely and 
fiinely granular ; margin smooth. Habit of Coseinodiseus minor, 
rather turgid on the side. Diameter 1-1 728th. Fossil, New Hampshire. 
D. (?) physoplea. — Small ; disc and margin smooth j with a cir- 
ciunscribed centre to the disc, bearing twelve large, vesicular-looking 
granules; limb, broad and smooth. Diameter 1-1 152nd. Fossil, 
Virginia. 

D. mammilla. — Smooth, thick, nummiform (money-shaped), 
suture of the valves tumid ; centre of the disc of each valve raised as 
a boss (umbo) ; marginal ring vanishing ; suture dentated on the side 
of each valve. Diameter 1-86-lth. Fossil on the coast of Patagonia. 
D. (?) cingulata. — A fossil species from ^gina, so named by 
Ehrenberg. 

D. radiata. — Also a fossil species from the same locality. 
D. atinospherica. — Margin of disc plane, mth broad and equal 
radiations ; central portion rather turgid and granular, naiTower 
than the striated border ; the granules and the striae becoming con- 



352 DESCRIPTION OF \_Po7i/ffasirica 

fluent. Diameter l-1008tli. ; forty rays in discs 1-1 152nd, vride ; 
in a few instances the rays and granules have not run together. 
Found in dust wafted about in the air. (P. 24, f. 1, 2.) 

DiscoPLEA sinensis. — Margin of disc plane, with equally disposed 
rays ; central part rather tm-gid and granular, narrower than the 
Btriated border ; with the striae and granules always separate, and 
circumscribed by a rim. Diameter 1 -864th. ; ninety-two rays in 
discs 1-1 152nd. broad; the rays are smooth, not rough as in D. 
atmospherica. China. (P. 24, f. 4.) 

D. aUantica. — Smaller ; central part rather granular ; rays equally 
disposed, but not cu-cumscribed so as to represent a rim as in the 
preceding. (P. 24, f. 3.) 

Genus Endictya. — Lorica bivalve, not in chains, subglobose, no 
apertui'es on the surface ; valves equal, simply bordered, not con- 
tiguous nor dentate, but with an intermediate cellular portion. 
These forms are Coscinodisci, with the discs separated laterally by 
an intervening cellular structure ; or they may, otherwise, be con- 
Bidered Dictyopyxides, with the valves not contiguous, but disjoined 
by the peculiar cellular band named. 

E. oceanica. — Large, disc and sides elegantly but irregularly 
cellular ; the cells of disc, howe\d, are almost concentric in arrange- 
ment, and seven in 1-1 152nd. Diameter l-528th. Fossil in African 
Guano. 

Genus Entomoneis. — Simple, not in chains ; valves equal, quad- 
rangular, smooth, with a distinct round umbilicus; apertui'es terminal, 
placed not laterally but quite at the extremities of the truncate ends. 

Entomoncides are smooth Diploneides or JSTaviculae, constricted at 
■(he middle, and having true terminal apertures. It differs from 
A^nyjJiiprora, by the absence of striae. 

E. alata = Navicula alata. — Laterally na\'icular, obtiise ; dorsally 
deeply constricted at the middle, with wide, truncate extremities ; 
margin expanded or alate (winged), very transparent, central portion 
with longitudinal lines; movements active (P. 16, f. 5, 6, 7.) Length 
J-570thto l-430th. North and Baltic Seas. 

Genus Entopyla (?) Sect. Echinellcea. — Lorica prismatic, com- 
pressed, multivalve, free, or in chains. Valves straight, contiguous ^ 
in regular series like the leaves of a book, with a large central aper- 



Naviculacea.'] INFUSORIAL animalcules. 353 

ture traversing the interior ; the exterior lamiua dissimilar, marked 
by transverse lines; one external valve quite entire, the other Avith a 
large pore at each apex. 

This genus, in being curved, approaches Achnanthes, but, by its 
external and ' tabellar form, is still nearer Tessella ; its closest 
affinity is with Bihlarium, which it resembles in internal structure. 
It occurs in quadrangular tablets or boxes, made up of several 
lamina, like the leaves of a book, but firmly connected. The lamina 
or leaves are parallel with the narrow sides, and curved : the outer- 
most leaflet on each side is thicker, like the cover of a book, and 
marked with thirty-two horizontal striae. These two outer sculp- 
tured lamina do not resemble each other as in Bihlarium, for one is 
concave, and the other convex ; the concave one constitutes the 
ventral surface, and has two large, round apertures at its two ends ; 
whilst the other (cover or dorsum) possesses no opening. The in- 
cluding or intervening leaves have each a large opening in the centre, 
and, consequently, but a narrow margin is left; and the little tablets, 
or boxes, have a continuous cavit^^ in their interior, such as also 
occurs in Bihlarium. The sculptui'ed covers have a considerable 
resemblance to Surirella. 

EuTOPYLA Australis. — Linear, landed at each end, in adult con- 
dition with sixteen intermediate leaves, in young specimens often but 
six ; external leaves (covers) marked (in the full grown state) by forty 
Btriae (costse), bisected by a flexuous line, as in Siirirclla. Length 
1 -240th. In 1843 Ehrenberg described this species imder the name 
of Surirella (?) Australis. Found in Patagonian Guano. 

Genus Epithemja (Kiitz.) — Transverse section of lorica trapezoid, 
transverse strite strongly marked, granular or moniliform. Locomo- 
tion has not been observed. Both the upper and xmder surfaces are 
traversed by two longitudinal Knes, terminated at each apex by a 
pore. It belongs to the family Emiotioi, and differs from Navicula, 
Cocconeis, Amphora, and Cymhella, by wanting a central opening, 
and from Fragilaria, by its two sides being unlike, one being concave, 
the other convex. Habitat, sea- water, on marine Algoe. 

E. Sorex. — Minute, dorsimi very convex, apices prominent, acute ; 
striae onvergent, twelve in 1 1200111 ; figure on the primary side 



854 DESCBIPTIOK OF {^Polygastnca- 

elliptic, and apices, though prominent, are rather obtuse. Length 
l-960th. 

Epithemta Musctdiis. — Dorsum elevated, apices somewhat acute, 
strias convergent, ten to eleven in l-1200th; primary sides broadly 
elliptic, subrotund, apices slightly prominent. Length 1 -420th. 
Brackish water in the Baltic (P. 16, f. 18.) 

E. Westermanni = Eunotia Westermanni (Ehr.) — On secondary side 
dorsum convex, apices gradually tapering, rather obtuse, not pro- 
minent striae scarcely convergent in the centi'al portion, seven to eight 
in l-1200th; on primary side elliptic. Length l-360th. 

E. Zebra = Eunotia Zebra (Ehr.) — Dorsum convex, apices very 
obtuse ; transverse striae of the centre convergent, five to seven in 
l-1200th ; primary side oblong. Length l-360th. 

£. Zelrina = Eunotia Zebrina (Ehr.) 

E. turgida = Eunotia turgida (Ehr.) 

E. Porcellus. — Large ; on secondary side, dorsum convex ; apices 
truncate, reflected ; transverse striaj convergent, eleven in l-1200th ; 
primary side linear, seven times longer than broad. Length 1 -240th 
to l-216th. Eossil at San Eiore (P. 16, f. 12.) 

E. Alpestris. — Secondary side arcuate, narrow; apices rounded, 
verj' slightly recurved ; transverse striae four to five in l-1200tli; 
primaiy side unequal. Length two to three times greater than width. 
(l-600th to l-324th. P. 16, f. 8.) Spring water, Tliun, Switzerland. 

E. ocellata = Eunotia ocellata (Ehr.) 

E. Argus = Eunotia argus (Ehi-.) 

E. gihberula = Eunotia gibber ula (Ehr.) 

E. Textricula = Eunotia Textricula (Ehr.) 

E. Saxonica. — Small, on secondary side dorsum convex, under side 
concave, conti-acting gradually towards the ends, which are slightly 
obtuse, rounded but not recurved ; transverse striae subconvergent, 
six to seven in 1 -1 200th ; primary side oblong, rectangular. Length 
1 -840th. Saxony and Italy. 

E. proboscidea. — Small ; on secondary side dorsum expanded, 
rather concave below ; apices constricted, obtuse, remarkably re- 
curved; transverse striae convergent, five to six in 1-1 200th ; primary 
side oblong, rectangular, with obtuse angles. Length 1 -540th. Eossil, 
Luncbf'""" 



Naviculacea.'] infusoeial animalcules. 355 

Epithemia llbrile = Eunotia lihrik (Ehr.) 

E. gibba = Eunotia gibba (Ehr.) — Large, straight, on secondary 
sido, dorsum gibbous at its middle ; apices rounded, very obtuse ; 
transverse strife parallel and very close ; on primary side, inflated at 
both ends. Length 1-1 44th. 

E. ventricosa. — Straight ; on secondary side, dorsum gibbous at its 
centre ; apices very obtuse, rounded ; transverse sti'ia3 parallel, close, 
thirteen to fourteen in 1-1 200th ; on primary side ventricose at the 
middle. Length 1 -450th. Germany. 

E. gramdata = Eunotia granulata (Ehr.) — Large ; on secondary 
side slightly arcuate, dorsum convex, apices roimded, very obtuse, 
recurved, ti'ansverse strite moniliform, six in 1-1 200th, their inter- 
stices very finely punctate; on primary side, elongated, straight, 
linear. Length 1-1 44th. 

E. Faba = Eunotia Faba (Ehr.) — Large, on secondary side slightly 
arcuate, dorsum convex ; apices but very little recurved, obtuse ; 
striae moniliform, seven to eight in I- 1200th, their interstices very 
delicately punctate; primary side oblong, dilated at the middle 
Length 1-1 80th. Fossil. 

E. vertagus. — Large, on secondary side slightly arcuate ; dorsum 
convex, with rounded and reflexm apices ; striae transverse conver- 
gent, ten in 1-1 200th, their interstices punctate; on primary side 
oblong, rather dilated at the centre. Length 1-1 68th. Normandy. 

E. (?) cingulata = Eunotia cingulata (Ehr.) 

Genus ErrjrEEiDiON (Kiitz.) Cuneiform, prismatic, trapezoid, con- 
joined in a wand or convoluted band, at length stalked. Striae trans- 
verse, strong, unbroken. 

Kiitzing has created this genus in the belief that Meridion con- 
strictum (Ealfs) possesses characters not belonging to Meridon, and 
such as are sufficient to sepai'ate it. 

The bands developed, resemble, generally, in their convolution, 
those of Meridion, but Kiitzing states that the transverse section of 
the frustules is trapezoid, and that they are attached, like species of 
Sgnedra, by a short, thick, gelatinous pedicle. 

E. constrictum = Meridon constrictmn (E,alfs.) 

Genus Ettnotia. — Lorica prismatic, striated, composed of one, two, 
or more ineces or valves. Lower or ventral surface flat, or rather 



856 DESCEIPTION OF {Polygastrica. 

concave, dorsal convex, and often dentate, with two apertures at each 
apex; lateral sm-faces plane. Sell-division complete, and hence the 
frustules are always solitary, or in pairs, during the process of fission. 
Found both living and fossil. Habitat, freshwater, parasitic on 
Algae. 

Eiinotia is closely allied to Nmicula, but differs in the absence of 
a central opening (umbilicus.) The cross section of the lorica is 
trapezoid, and the transverse sti'ise ai'e uninterrupted, i. e. unbroken, 
" The frustules are simple or binate, quadrangular." 

Eunotia are mostly found attached, by their concave surface, to 
various fresh water Algas. 

" Some species," says Mr. Ealfs (Ann. Nat. Hist. 1844, p. 459), 
placed by Ehrenberg in this genus, have cymbiform frustules, and 
belong to Agardh's genus Cymhella. 

" In Eimotia the finistules resemble those of some species of Fragi- 
laria, but are not united into a filament. Viewed laterally the frus- 
tules are lunate. The convex dorsal surface is generally raised in 
transverse ridges (dentations, Ehr.) ; and the number of these ridges, 
as seen in a lateral view, when they appear like teeth, distinguishes 
the species. Prof. Bailey suspects that the number of these teeth is 
liable to variation, and that the'* number of species has, in conse- 
quence, been made too great." 

Besides multiplying by self-division, the Eunotim have been 
observed by Mr. Thwaites, and others, to propagate by conjugation. 
(P. 14, f. 1 to 8.) Frustules developed in the latter mode are larger 
than the parent beings producing them, and in their early stage are 
siu'rounded by mucus, and not striated. "Where the number of 
dentations is equal in two forms, and so cannot furnish a specific 
character, then the variations in the figure of the lorica generally, 
and particularly of its apices, are employed. 

Etjnotia turgida. ^= Epithemia turgida (Kutz.) — Lorica semi- 
lanceolate; ends truncate; striated; striae eight in 1-1 200th. 
Dorsum convex. A longitudinal furrow runs along the middle of each 
side ; scarcely visible in living specimens, owing to the colour of the 
body. (Group 157, P. 3, and f. 158, 159, 160, and 161, P- 14, 
f. 1 to 8.) Foimd upon Vauchcria and Conferva. Length 1-11 50th. 
to 1 -240th. 



N'avieulacea.l inffsorial animalcules. 357 

E0NOTIA Westermanni. = Epithemia Westermanni (Kiitz.) — Semi- 
lanceolate, oval, with ten striae in l-1200th. It is of arichochre colour. 
(In group 157.) Found witli the preceding. Length l-1150th. to 
l-480th. 

E. Zebra. = Epithemia Zehra (Kiitz.) — Striated, semi-lanceolate, 
oblong, with five transverse sti'iae in 1-1 200th. The strioe are seen 
with difficulty except when the lorica is empty, or fossil. Length 
1-1 840th. to l-570th. Found on fresh-water Algse, and fossil at 
San Fiore, &c. 

E. granulata = Epithemia granulata (Kiitz.) — Striated, semi-lan- 
ceolate ; elongate, slightly arcuate ; surface granular, beiug minutely 
dotted iu the interspaces of the moniliform strige. Striae five in 
1- 1200th. Length 1 -240th to 1-1 40th. Fossil in Germany, United 
States. (P. 3. f. 165.) 

E. Faba = Epithemia Faba (Kiitz.) — Striated, semi-oval, Lq the 
form of a bean j slightly arcuate ; apices obtuse, very little recurved, 
StrisB moniliform (dotted), nine in l-1200th. Length 1-1 150th to 
1 -570th. FossU. 

E. diodon. — Striated on the lateral surfaces, which are narrower 
than the plane central surface ; apices obtuse, rounded and tapering ; 
dorsum convex, obtusely bidentf^'e, with two obtuse ridges at its 
centre. Length 1-5 70th. Fossil. 

E. triodon difiers from E. diodon, in having three dentations. 
Length l-570th. Fossil. (P. 3. f. 164.) 

E. tetraodon. — Large ; dorsum very convex,and venter very concave; 
constricted near each end, which is roimded ; dorsum with four large 
rounded elevations; stria? strongly marked. Length 1-5 70th, 
Living, Falaise ; fossil in Finland. 

E. pentodon, similar to E. diodon. — but dorsum with five ridges ; 
ends attenuated, rounded. Fossil. 

E. Diadema. — Six dentations, ends rounded. Fossil. 

E. serr«.— Large, lunate, dorsum siuuose, with twelve to thirteen 
indentations. Length 1 -280th. Fossil in Sweden and North America. 

E. gibba = Navicula gibba (Ehr.)_Striatcd, dilated at the middle, 
and gibbous, oblong; ends dilated and rounded; striae nine ia l-1200th. 
Length 1 -430th to 1-1 20th.- Living, Gravesend; fossQ, Isle of 
France. (P. 15. f. 27.) 



35S' DESCBIPTION OF {Tolygasirica. 

EimoTiA Diana. — Striated, linear, rather broader than deep altus) ; 
dorsum convex ; venter concave ; apices arcuate and slightly rcfllexed. 
Strife thirteen in 1-1 200th. Length 1-2 16th. Brandenberg. 

E. fieptodon. — Striated, short and semilunar ; venter concave ; dor- 
sum convex, with seven obtuse dentations (teeth). (l-576th). In 
fossil meal, Sweden. 

E. ododon. — Like preceding in form and size ; eight dorsal denta- 
tions. (l-576th.) 

E. enncaodon. — Striated, straight, or curved; venter plane or 
concave ; dorsum with nine obtuse teeth. (l-432nd.) 

E. <?ec«of?ow.— Semilunar, venter concave, ten obtuse teeth. (1 -480th.) 
Eossil in Sweden and North America. 

E. Rendecmdon.—Cva~\Q(\., with eleven obtuse teeth. (l-450th.) 
Fossil. 

E. serrulata. — Linear, cu.rved ; dorsum convex, thirteen obtuse 
teeth. (l-432nd.) North America. 

E. prionotus. — Striated, almost straight and linear ; fourteen 
dentations. (1 -289th.) Sweden. 

E. hisoctonaria, — Striated, linear, slightly curved ; sixteen dorsal 
teeth. (1 -280th.) Fossil. 

E. ieosodon. — Twenty teeth. (l-i06th.) If more than twenty 
teeth, '^- polyodon. Fossil. 

E. nodosa. — Slightly arched ; expanded at the centre on both sides ; 
apices reflexed, obtuse. (1 -240th.) Fossil, Barbadoes and North 
America. 

E. cow^a— Small, curved, rounded at each end ; dorsum regularly 
convex; striae strong and granular. Length 1-1 152nd. In Greek 
marl. 

E. Hellenica. — Long, somewhat curved, apices rounded ; dorsum 
uniformly convex ; very delicate striae, intervening between the few 
but strong internal costaj. (l-480th) In Greek marl. Costse four 
in 1-1 200th. 

E. ocellata ■= JEpithemia ocellata (Kiitz.) — Small, oblong, curved ; 
ends rounded ; back regularly convex ; striae strong and close, seven 
in 1-1 200th. Length 1-1 152nd. In Greek marl and in Peru. The 
three preceding species approach E. Faha in form. 

E. amphioxys. — Narrowly linear, dorsums lightly convex, smooth ; 



Navieularca.'] INFirsORIAt ANIMAtCTTLES. 369 

venter slightly concave, minutely striated ; ends suddenly contracted 
and produced ; approaches E. Diarue. (l-480th.) 

EcTNOTiA Arr/us. — Striated, dorsally oblong, regulai-ly quadrangular, 
with a double row of pores (ocelli), approaching it to E. ocellata, 
■which however is constricted towards each extremity. Cuba, 
Mexico. (P. 24. f- 11.) 

E. biceps. — Striated, narrowly linear, curved, apices roxmded ; and 
a little revolute. North America and Falkland Islands. 

E. bidens — Striated, ; venter flat ; dorsum convex, wdth a central 
furrow, rendering it bidentate ; apices dilated, truncate. It resembles 
E. diodon, except in its truncate extremities. America. 

E. Camelus. — Small, striated ; dorsum with a double boss or hump ; 
extremities produced, slender, obtuse. Cayenne and Labrador, 

E. (?) cingulata = Epithemia cingulata (Kiitz.) — Smooth, small, 
dorsum convex ; margin of ventral surface tumid. It is divided by 
a longitudinal prominent band into two halves; approaches E. 
gibberula 

E. decUvis. — Wider, striated; venter flat; dorsum convex, with a 
moderate groove, making it bidcndatc ; the dentations continuoug 
with the acute apices by a straight descending line. 

E. de2)ressa. — Striated ; nail^wly linear, rectangular ; venter 
plane or slightly concave; dorsuna rather depressed, suddenly 
contracting towards the rounded apices. Length I-408th. Eossil, 
Ireland, and in tropical America. 

E. dki/ga. — Striated (?) wider; venter concave ; dorsum convex, 
with four dentations, approximating at the centre, Cayenne. 

E. JElephas. — Striated, very broad curved, apices broadly rounded ; 
back tridendate. Brazil. 

E. Formica. — Stiiated, Knear ; turgid on each side of the centre, 
apices also enlarged. It = E. nodosa, with ends not reflected, but 
enlarged and straight Central and North America. 

E. gibberula = Epithemia gibberula. (Kiitz.) — With dotted strife, 
smaU; dorsum widely expanded; apices constricted, recurved. 
Mexico, Connecticut. 

E. Lihrile = Epithemia Librile (Kiitz.) — Long and narrow, with 
dotted interspaces between the sti-ise ; venter concave ; dorsum at its 



860 l)EscEiPTioN OF [^Poli/gasiricat 

middle portion evenly convex, but decreasing suddenly towards the 
slightly revolute and obtuse ends. Mexico. (P. 15. f. 24, 25.) 

EiTNOTiA monodon. — Striated, elongate ; venter concave ; dorsum 
evenly convex; constricted slightly near the rather recurved 
ends. (P. 15. f. 27.) 

E. parallela. — Linear, strongly striated, curved, apices simply 
rounded. North America. 

E. pileus. — Small, striated, subquadrate, as seen on the sides ; the 
under surface is wider than the upper ; the latter slightly furrowed ; 
ends obtuse, rather prolonged. Siberia. Fossil. 

E. lofifficornis. — Large, elongated, dorsum continuously convex; 
extremities rather reflexcd ; venter concave ; surface marked laterally 
by many wide costae, alternating ^vith more or less rounded or quad- 
rate spaces, which are also striated. It is allied to E. Argus. (P. 24, 
figs. 6 to 9.) 

E. prcerujjta. — Striated, elongate, back curved evenly and continu- 
ously to its dilated and truncated extremities. 

E. quarternaria, — Small, narrowly linear, cui-ved; back four-toothed ; 
apices somewhat recurved. Liberia, Cayenne. 

E. quinan'a. — Small, narrow, linear ; dorsum but sKghtly convex, 
with five dentations ; ends rounci*,'^, Siberia, New York, Guano. 
(P. 15. f. 39.) 

E, Sella. — Striated, dilated ; dorsum, with a central groove^ 
bidentate ; continued as a regular ciuwe to the acute ends. 
Cayenne. 

E. septena. — Small, narrowly linear, with seven dorsal dentations. 
Labrador. 

E. Textricula = Epithemia Textricula (Kiitz.) Small, with paral- 
lel sides ; back evenly convex ; convexity prolonged to the round, 
not tapering extremities ; striee lateral, few and strong ; their inter- 
spaces ■with fine longitudinal lines. Fossil, Iceland and Mexico. 

E. Tridentula. — Small, narrowly linear, stiiated; dorsum triden- 
tate. Fossil, Iceland, Cayeime, and Connecticut. 

E. centralis. — Large, linear, striated, curved ; venter turgid in the 
middle ; dorsum even ; apices enlarged, rounded. North America- 



Narieularea.'] infttsortai, VNiMALcrtEs. ;^61 

EuifOTiA uncinafa. — Small, uarrow, linear, curved; apices muck 
constricted and capitate. North America. 

E. Zelrina = Epitheinia Zebrina (Kiitz.) — Striated, elongate; 
dorsum evenly convex ; the convexity extending gradually to the 
constricted but obtuse apices ; interspaces of striae dotted, " probably 
identical with E. zehra,'" Kiitzing. New York and Ehode Island. 

E. zijgodon. — Striated, linear, oblong ; back with a furrow, render- 
ing it bidentate, and its convex curve extending to the rounded 
apices. Guiana 

E. Creta. — Of Caltanisetta, Sicily = Cocconcma Crsf^. 

E. amphidieranoyi. — Striated, oblong, straight, quadrangular ; con- 
stricted on each side at the middle ; extremities emarginate, furcate, 
(l-864th.) Fossil, Oregon. 

E. crocodilus. — Elongate, sti'iated, gently curved ; back convex, 
depressed in centre ; venter concave, gibbous at its middle ; ends 
subacute, rcflexed. (1 -576th.) 

E. Lima. — Striated, linear, with a lunate curve ; dorsum evenly 
convex ; venter concave, gibbous at its centre ; ends simply obtuse. 
(l-372nd.) Fossil. 

E. Siind. — Striated, linear, more gradually curved ; dorsum rather 
convex ; venter concave ; ends -^^liquely subtruncate, and apices 
reflex. (1 -456th.) Fossil. 

The following new species were discovered by Ehrenberg, iu 
earth from New Holland : — 

E. caelafa, E. Amtrdis, E. cygnm, E. paradoxa. 

E. senaria and E. nonaria. — New species, discovered by Ehrenberg, 
in earth fi'om Siberia. 

E. Alpha (Kiitz.) — Binate, primary side linear ; rectangular on 
the other, dorsiim convex, apices obtuse, truncate, transverse stride 
very slender. (1 -960th to 1 -600th.) Bernese Oberland. 

E. monodon. (Ealfs.) — Lateral view concave on one margin, 
convex on the other ; constricted near the ends ; striae none or very 
obscure. Fresh water pools. 

" The frustules are very minute, but vary greatly in length, beino- 
in some specimens only twice as long as broad, and in others six or 
seven times longer than broad. The front view has its ends slightly 
rounded, and its pimcta very obscure. The absence of stri® may be 



36^ DESCEiPTioN OF IPoli/ffastriea. 

due to the minute size of the specimens under my notice, as I have 
occasionally observed veiy faint lateral striae. A fiaistule of this 
species, though veiy much smaller, has a great resemblance to a 
soKtaiy one of Fragilaria pectinalis ; but in this plant the concavity 
of one margin is generally gi'eater, and the constriction near the 
ends of the frustules more considerable ; the front view, too, is 
nan'ower in proportion to the lateral ; stiU it may eventually prove 
to be only the commencement of that plant." 

This is probably identical with E. monodon of Ehrenberg.. 

Genus Euronisctrs. — Lorica simple, valves equal, orbicular, not 
concatenated; unilocular, furnished with tubular processes, per- 
forated at the apex, projecting from near the margin. 

The number of tubules was at first employed by Ehrenberg as a 
generic characteristic, but he now assigns to it but a specific value. 

Eupodiscus is therefore equivalent to the previously-named genera, 
Tripodiscus, Tetrapodiscus, and Pentapodisciis. 

E. Germanicus. — Has three tubular processes, and eighteen cells 
in 1 -1200th. The lorica large, orbicular, and rather compressed; 
cells in radiating series ; processes short and hyaline. Colour green. 
Cuxhaven. (P. 14, f. 41, 42.) 

E. qiiaternarnis. — Foirr appendages. 

E. quinarius. — Five processes. 

E. momtruosus. — Pour processes on one side. Diameter 1 -240th. 

E. Roger sii. — Has six appendages round its periphery ; valves 
with four-and-a-half large cells in l-1200th., together with five 
radiating series of granules, ten in 1-1 200th. Diameter 1 -204th. 
Vu-ginia. 

'E. Baileyi. — Seven processes around its circumference. Virginia. 

E. radiatiis (Bailey.) — In form, size, and reticulation, resembling 
the Coscmodiscus radiatus of Ehrenberg, but having foiu" (or more) 
foot-like projections near the margin. A common form in the 
Southern States of America. 

Genus Feagilaria. — Lorica simple, bivalve or multivalve, prismatic, 
having a general resemblance to Nwvicula ; striated on the sides, 
leaving a central clear portion. In most species each extremity is 
furnished with two openings ; these being in the same plane, the 
surfaces upon which the chain rests may be considered lateral, and the 
self-division will then be dorsal. The whole chain sometimes rises 



Kaviculaeea,'] iNFrrsoniAL animalcules. 363 

in the water and turns upon itself ; detached frustules have a pro- 
gressive movement. The granular contents are green or yellowish 
when young, but reddish brown when old. The most evident manner 
of propagation is dorsal self-di\dsion. In many species growth con- 
tinues both diu'ing and after self-division, but in F. striatula increase 
of size ceases after division. 

In Hooker's British Flora, the characters thus stand, — " Frustula 
forming plane, pseudo -articulated, densely striated, fragile filaments, 
separating at the striae (not cohering at their angles.) Named from 
their fragile character." 

This genus gives name, and is the type of the family FragilaricB of 
Kiitziug, which also includes the genera Benticula, Odontidiwm, and 
Dkitoma. 

Mr. Ralfs observes, (Ann. [N'at. Hist., 1843.) "This genus is 
nearly allied to Biatoma ; the chief distinction between them is, that 
in Biatoma the frustules cohere at the angles, and in FragiUria do 
not. In one species of the latter this difference does not exist ; it 
seems therefore an intermediate form." 

" The puncta at the ends of the frustules, in this and other genera 
of the CymheUea;, I have never found any reason to believe to be 
openings, as many naturalists have-oupposed. Mr. Borrer informs me, 
that in Fragilaria pectmalis they are the terminations of slight 
grooves." 

Besides multiplying by fission, described by Ehrenberg, the fr'us- 
tules of Fragilaria also conjugate and produce new forms. 

The followuig strictures by Kiitzing, on some of the specific dis- 
tinctions of Ehrenberg, employed in this genus, occur in a note to 
the description of Fragilaria ca-pucina (Kiitz.) 

" It varies much in length and breadth, the single frustules as 
well as the bands. The contents also are subject to the same 
variations as those of other Biatotnece. Nevertheless, Ehrenberg has 
made use of these variations in the institution of several species. 
P. 1 7, f. 1 is a tolerably common variety, which always appears 
in very long bands. These bands are often twisted, and, owing to 
this, appear smaller at some parts than at others, seeming to be 
broader when lying flat, and smaller when at an acute angle. The 

BB 2 



364 DESCKIPTION OF \^Polygash-ica. 

shorter bands belong to Ehrenberg's Fragilaria rhabdosoma; p. 17, 
fig. 3 is F. hipunctata ; figs. 4 and 1 2 is F. diophthalma ; figs. 2 and 7 is 
F. Scalaris ; figs. 5 and 8 is F. mtdti2}uncfata ; fig. 9 is F. Jissa ; 
whilst figs. 10, 11, and 6, represent the F. tenuis of Agardh." 

Feagilakia grandis. — Striated, lanceolate ; laterally, ends obtuse. 
As many as thirty frustules often cluster in a single band. (P. 3, 
f. 171.); striae 11 in l-1200th. Length of single rods or frustules 
1-5 70th. to l-120th.; vide F.pectinalis (Ralfs.) 

F. Glans. = Navicula (? ) glans (Ehr.) — Short, striated, expanded 
in the centre, so as to recal the figure of an acorn ; ends constricted, 
obtuse. Stiia) two to three in 1-1 200th. Fossil. Length 1-1 150th. 
to 1 -570th. 

F. scalaris. Tlie ladder-lilce Fragilaria. — Smooth, seven to eight 
times longer than broad ; granules of a fallow hue. Breadth of 
band («. e. length of fnistule) l-860th. to l-570th. 

F. diopliiliahna. — Smooth, three to four times longer than broad ; 
granules (ova, Ehr.) of a golden yellow coloiu', disposed iu ten 
portions. Length 1 -960th. to 1-1 150th. 

F. pectinalis. — Striated, two to six times longer than broad ; 
dilated and lanceolate on the lateral surface ; striae eight in 
l-1200th, ; granules yellow. In^e living state the striae are very 
indistinct. (P. 3, group 1 76, a band, and the side view of a single 
ftaistule.) Common in ponds. Length l-2200th. to l-430th. 

F. rhabdosoma. — Smooth, slender, and fi'om five to twenty times 
longer than broad. The extremities of the unsti'iated lateral surfaces 
are needle-shaped. In some chains, the specimens are imited 
together firmly ; in others, the bands easily drop to pieces, the portions 
detached exhibiting locomotion, and may easily be mistaken for 
Synedra or NavicuJa ; but the number and position of the openings 
are the distinguishing marks, (figs. 173, 174.) They are pale 
brown when recent, when dried greyish. Living in fresh water, 
fossil at Cassel. Length 1-5 70th. to 1 -200th. 

F. twrgidula. — Striated, and from two to three times longer than 
broad, as seen in group 1 72 ; margin with many dentations ; striae 
six to nine in 1-1 200th.; on secondary side lanceolate and rather 
obtuse. Length l-720th. to l-570th. Berlin. 



Naviculacea.l infusobial animalcules. 365 

Fragilaria maltipumtata. — Smooth, sleuder, eight to sixteen 
times longer than broad; ova of a yellow golden coloiu', and 
midtipartite. Found amongst Conferva, Length l-570th. to 
l-280th. 

F. bipundata is probably identical with F. rhahdosoma; it is smooth, 
and four to five times longer than broad. The granules are of a 
golden-yellow colour, and contracted into the form of two rounded 
spots. Found near Mount Sinai. Length 1-1 200th to l-760th. 

F. angusta. — Smooth, and five to six times longer than broad. 
Length 1 -480th. to 1-5 70th. 

F. (?) anccps. — Small, linear ; laterally is loosely striated ; apices 
constricted, sub-capitate, obtuse ; allied to Goniphonema pupula. 
Korth America. 

F. hicsps. — Small, linear, smooth ; apices constricted, abruptly 
subacute. 

F. (?) Ihiodis. = Navicular b/nodis. — Quite smooth, small, narrow, 
panduriform (fiddle-shaped), constricted at the centre, and at each 
end; apices acuminate. Length 1 -900th. 

F. (?) constricta. — Linear, oblong, smooth ; central constriction 
slight ; apices suddenly acute. Falkland Islands and Mexico. 

F. Entohion. — Lincai", elougate'Jv.mooth, central constriction strong, 
apices rostrate. 

F. (?) glabra. — Linear, smooth ; aj)ices slender, but obtuse. May 
be avariety of F. J/«^s. Guiana. 

F. (?) l(evis. — Resembles F. amphiceros, but destitute of the dotted 
striae. Virginia. 

F. (?) Navicula. — Oblong, smooth ; dorsally four to five times 
longer than broad ; central constriction very slight. Peru. 

F. pinnata. — Testules three to six times longer than broad; 
linear, oblong, with sti'ong striae, fifteen iu 1-1200 th; apices simply 
rounded, allied to F. Syriaca- Mexico, Iceland. 

F. (?) striata. — Oblong, tiu-gid ; striae few but distinct. May be 
a variety of F. pinnata. Of the ten species just described, Ehren- 
berg makes the observation that he has not seen all of them con- 
catenated, but often only single segments ; consequently their genus 
is doubtful. 

F. leptoceros — Laterally rhomboid, linear, elongate, ends attenu- 



366 DESCRIPTION OF \^Polygastrica. 

ated, sti-aight, and acute ; margin very finely striated ; central space 
smooth. Diameter 1 -432nd. Eichmond, Virginia. 

Feagilaeia Amphiceros. — This species -was described in 1843, by 
Ehrenberg, as a doubtful Fragilaria, and as equal to a Cocconeis de- 
prived of its central foramen. His latest description is : Testule 
narrowly linear, rather turgid in the middle ; apices much attenuated, 
but truncate ; surface remarkable by its transverse strise throughout. 
It differs from EJiaphoneis by the want of a median longitudinal band. 

F. Bacillum. — Smooth, laterally linear, rounded at each end ; five 
to six times longer than broad. Length 1- 720th. Oran, Africa. 

F. striolata (1844) ;= F. pinnata. 

F. nodidma. — Linear, twelve times longer than broad ; striated 
transversely; stiiae eighteen in l-1200th; narrowly linear laterally, 
constricted below the apices, marked by narrow rows of nodules. 
Length l-648th. Kurdistan. Transverse striae (nodules) of the 
sides eighteen in 1-1 152nd. 

F. hirostris. — Very small, suddenly attenuated at the acute ex- 
tremities, laterally lanceolate. Has nearly the characters of a 
Staurosira (l-3120th.) 

F. granulata. — ^Habit of F. Amphiceros, but stouter, tapering to- 
wards the ends ; pirmules disposecf^i bundles, and granular. (l-720th.) 

F. pinnulata. — Bacillar, equal throughout, often five to six times 
longer than broad ; laterally rounded at each end, not attenuate ; 
pinnules twenty-five in l-1200th. (l-1152nd.) 

F. rotundata. — Bacillar, equal throughout j length often nine 
times greater than breadth ; laterally rounded, not contracted at the 
two extremities; twenty strong pinnule? i i l-1200th. Length l-480th. 

F. 2whjedra. — Oblong, angular (hexangular ?) bacillar ; length three 
times greater than width ; transverse striae (pinnules) delicate. 
Length 1 -900th. Fossil at Norwich. Connecticut. Allied to F. 
Bacillum. 

F. (?) mesotyla. — Bacillar, tiirgid at the centre, ends obtuse, ti'ans- 
versely striated, striae granular. Longth 1 -480th. Very like Staur- 
optera granulata, but wants the longitudinal band and crucial um- 
bilicus. 

F, (?) Stylus. — Fossil, discovered by Ehrenberg in marl from 
JEgina. 



Naviculacea.] infusorial animalcules. 367 

Fkagilama (?) Stjjlidiam. — Fossil, from the same locality. 

F. Seminulum (Eht.) — Fossil, in earth frqpi Siberia. 

F. Syriaca. — Tcstules eight times longer than broad, striae wide 
apart, ten in l-1200th. Length 1 -960th. Marine, Syria. 

F. mesodon. — Length not much greater than breadth (subquadrate), 
centre rather turgid on the lateral aspect, ends obtuse, constricted ; 
four strife, and teeth about the middle, only on the sides. Secondary 
side elliptic-lanceolate, dilated at the middle, -with two to four striae. 
Length 1- 1104th. Friburg, in Switzerland, among Conferva. 

F. Catena. — Smooth, length twice the breadth, ovate laterally. 
Length 1-1 152nd. Mexico. 

F. acuta. — Smooth, linear, length six times the breadth ; laterally 
cuneate, acute. Length l-576th. Among Conferva; Friburg, Switzer- 
land. 

F. Capucina (Kiitz.) — Filaments more or less elongated, segments 
linear, rectangular ; on secondary side acute and narrowly lanceolate. 
Common. This plant, according to Kiitzmg, represents the species 
named by Ehrenberg, respectively, Fragilaria rhabdosoma, multipunc- 
tata, bq)anctata, angusta, scalar is, diojjhtJialma, and fissa. 

F. corrugata. — Segments geminate, corrugated on each side ; on 
secondary side acutely lanceolate,^^ Length 1- 1440th. Fresh water, 
Nordhausen. 

Kiitzing adduces this species as synonymous with F. confervoides 
(Gre\Tlle), thus described (Hooker s British Flora, vol. ii, p. 407.) — 
Filaments elongated, attenuated, compressed, excessively fragile, the 
joints about as long as they are broad {i. e. considering the breadth 
of the frustules to be that of the chain.) Streams. Tufted, two to 
four inches in length. 

F. hj emails (Ann.- Nat. Hist., 1843, Lyngbye.) — Frustules broad, 
puncta at the ends very minute, lateral surfaces broad, elliptic-lan- 
ceolate, with well-marked striae, which terminate in distinct puncta 
along the margins. Foiuid in fresh-water pools and rivulets. 
Brownish when recent, whitish brown when dry ; filaments elongated, 
attenuated, very fragile, separating into single frustules almost imme- 
diately after being gathered. Mature frustules generally two or 
three (occasionally five or six) times longer than broad. 

In Hooker's British Flora, tlu-ee other species, named, respectively. 



368 DEscEiPTioN OF [Poli/gasirica, 

F. aurea, F. (liatoiiioiihn, and F. striatula, are described ; but beiiig 
all marine, contrary to tbe habitat of the time Fracjilaria, probably 
belong to another genus, which Kiitzing supposes to be Grammonema 
(Agardh.) 

Besides indicating F. virescens to be in part represented by F. pec- 
tinalis (E), Mr. Ralfs describes (Ann. Nat. Hist., vol. xii, 1843) a 
ep-'cies under the latter appellation, but differing in characters from 
the similarly named one of Ehrenberg. 

'E-b.x.giulKIA. pectinalis (Ralfs.) — Frustules broad, with two evident 
puncta at each end ; lateral surfaces striated, curved, constricted on 
one side near the end. 

Var. {h.) — ^Found near Barmouth. F. pectinalis is brown when 
recent, but when dried is of a pale greyish-green colour, with a 
glass-like lustre. The endochrome is commonly contracted into two 
irregular lines, which are not unfrequently united at the centre ; but 
often it is in four patches, apparently from the di^^.sion of these lines. 
The frustules sometimes have a central pellucid spot, which does not 
appear to be connected with the endochrome. I have, several times, 
met witli a remarkable state of this species, and have also received 
it from Mr. Jenner. "Within the frustules, there is, apparently, 
another siliceous frustule, the latei^i' margins of which are rounded, 
having sti'iae like the outer frustules. In the longer frmstules it is 
nearly elliptic ; but, in the shorter ones, appears as if truncated at 
the ends, and, in both, it occupies the whole interior of the frustules, 
except the corners, where the puncta at the ends are situated ; it is 
filled with a yellowish.green granular mass, mixed with numerous 
colourless vesicles. 

The lateral surfaces (of F. pectinalis) are very characteristic ; one 
margin is flat, or slightly concave, the other convex, and slopes off 
rather abruptly near the ends, where also it is slightly constricted. 
Besides these constrictions, indications of two others may often be 
observed on the convex margin ; but, in a specimen sent me by Mr. 
Slaney, these are so strongly marked, that if I had not seen inter- 
mediate forms, I should have supposed it a distinct species. I have 
made it var. {h) — F. undulata, which perfectly agrees with the usual 
state of the species, except in the lateral view, the convex margin of 
which has two indentations, giving it an undulated appearance ; the 



Navicidacea.'] infusorial animalcules. 3(59 

other margin is flat, with a projectiou iii the centre. In both fonns 
the lateral surfaces are marked with close transverse striae. Mr. Ralfs 
appears to regard fig. 171, as representing this variety. 

Feagilaria vireHccns (Ualfs.) — Frustules broad, with two evident 
puncta at each end ; lateral siu'faccs turgid, lanceolate, constricted 
near the ends ; striae none, or indistinct. Fresh water pools. Plant 
green, not much altered in drying. The frustules frequently separate 
and cohere by the angles in a zig-zag chain, from which circum- 
stance it is doubtful whether the plant is rightly placed in this genus. 
The frustules are often nearly square, but more frequently three to 
four, or sometimes five to six, times longer than broad. The endo- 
chrome is greenish, and consists of numerous small granules, either 
scattered or collected together in the centre of the frustules. 

When the frustules adhere together by their angles, this plant 
bears a considerable resemblance to young specimens of Diatoinavulgare, 
from which, however, it may be distinguished by its green colour 
when recent, by the form of the lateral surfaces, and by the apparent 
absence of striae under a moderate power of the microscope. 

Mr. Ralfs considers this sjiecies = F. pectinaUs (E.) ; Kiitzing 
tliirLks it = F. confervoides of Greville ; but the former says it is not, 
for F. confervoides (Grev.) he haS^iscertained to be F. hyemalis. 

Genus Gallionella (Ehr.) = Mehsira (Agardh.) — Lorica bivalve, 
cylindrical, globulai', or discoid, concatenated, chain free. The seg- 
ments (frustules) have each one or two oblique furrows, with several 
openings in them. The lorica, viewed end ways, is circular, re- 
sembling a coin. It is fragile and incombustible ; that of G. ferni- 
ginea (see description of this species and remarks) appears to be com- 
posed of silicate of iron. A coloured and divided mass of granules 
(ova, E.), clustered like grapes, is seen internaUj', as also colourless 
vesicles. Change of place has not been seen. lu their concatenated 
form, they closely resemble filamentous Algae. Nearly all the species 
are found both fossil and living ; the fossil forms, especially, are 
exquisite objects for the microscope, under a high power and proper 
illumination. Living forms occiu' both in fresh and in salt water. 

Kiitzing' s definition difters from that of Ehrenberg, mainly in de- 
scribing the filaments as adnate, or attached. Like Mr. Halt's, the 



370 DESCRIPTION or {Tolygastrica. 

first- named naturalist makes two sections of this genns, according as 
the segments are globular or elliptic, and keeled (The term keeled, 
carinatus, is ai:)plied by Kiitzing to the opposite sides of each seg- 
ment, which ai^pcar produced beyond the jB.rst or chief circle, or cut 
off by a segment of another circle from it), or cylindrical and not 
keeled ; calling the first Lysigonium, the second Gallionella. " This 
genus," says Mr. Ralfs {Jinn. Nat. Hist., vol. xii, p. 347), "in 
its cylindrical filaments, differs from the other Cyinhellm, and thus 
connects them with the Coufervte; but it agrees with them in being 
generally of a brown or yellowish colour when recent, and especially 
in its siliceous filaments, and in the presence of striae ; characters 
which sufficiently point out the propriety of its present situation 
among the Diatomece. The filaments have no proper margins marked 
by distinct characters, as in the other genera of Cymhellece (Diatomea;) ; 
and the stria3, ■N\hcn present on the junction-sui'faces, are not trans- 
verse, but radiated. 

"In the fii'st section of this genus, the species belonging to which 
are generally' marine, the ends of the frustules are convex, and as 
there are no distinct jimction-sui-faces, a moniliform appeai"ance is 
produced. The central line is more strongly marked in this than in 
the other section, and seems to dVfide the frustules into two equal 
portions. It becomes broader, and at length double, and, ulti- 
mately, an intermediate growth separates the two halves of the 
frustule, which, during this process, do not increase in size ; but 
when the intermediate space is equal to the diameter of the original 
fi'ustulc, two new frustules are formed, by the addition of two hemi- 
spheres on the inner sides of the separated portions. The outer sili- 
ceous covering still remaining, the frustules are connected in pairs, 
and appear like two globules within a joint, as they are charactciized 
by Harvey in G. nummuloides, and by Cannichael in G. globifera. 
The above description belongs more particularly to G. nummuloides, 
but the process in the other species, in the first section, is the same ; 
a series of changes, nearly similar, occurs in Isthmia. 

" All the species in the second section are found in fresh water. 
The frustules are not united in pairs ; their junction-surfaces are 
distinct, and nearly flat, and their central lines are probably furrows ; 
hence, whatever parts of these lines occupj- the margin of the field 



Naviculacea.'] infusoeial animalcules. 371 

of view, as the filaments are turned round, they all appear like 
puucta. 

" * Filaments moniliform, frustules united in pairs. Species G. . 
nummidoides, G. Borreri, and G. glohifera. 

" * * Filaments not moniliform, irustules cylindrical. Species G. 
arenaria, G. varians, and G. aurichalcea. 

"* * * Filaments very slender, joints obscure. Species G. ochracea.'" 

Mr. Thwaites has proposed (.inn. Nat. Hist., 1848) another 
arrangement of Melosira — subdividing it indeed into three genera — 
viz., Aulacoseira, Orthoseira, and Melosira. This subdivision he would 
base on differences observable both in the character and position of 
the sporangia, and in the form and structure of the frustules them- 
selves. 

The genus Melosira (says Mr. Thwaites) as it stands, after this 
removal of some of its species, will include all those whose frustules 
are in any degree convex at their extremities, and have the central 
line indicating the place of future fissiparous division. It will 
probably be found expedient to separate Melosira arenaria (Moore, 
see page 376) from its present congeners, when its sporangia have 
been discovered. 

Besides multiplying by fission, the Melosira GaJlioneUa (Ehr.), 
develope new frustules by the formation of sporangia ; and, although 
these sporangia are not the result of an evident conjugation, or mix- 
ture of eudochromes of two frustules, as witnessed in many of the 
Diatomeoi, yet Mr. Thwaites concludes, that the difference in the 
phenomena, though structural, is not physiological. In tliis genus, 
a change takes j^lace in the endochi'ome of a single frustule — that is, 
a disturbance of its previous arrangement, a moving towards the 
centre of the frustules, and a rapid increase in its quantity ; subse- 
quently to this it becomes a sporangium, and out of this are developed 
sporangial fr'ustules as in other JJiatoniece. 

In the system of Kiitzing, this genus gives name to the family 
Melosirce, which comprise the genera Cyclotella, Pyxidicula, Fododiscus, 
Podosira, and Melosira. 

The same observer states that Melosira is attached by a soft, gela- 
tinous pedicle, proceeding fi-om the middle apertui-e of the veiitral 
surface, a characteristic of this genus. 



372 DESCRIPTION OF {^Polygosimca. 

Gallionella lineata. — Cyliudi-icul, tlie ends couucctiug tliem together 
{ihv junction surfaces) comiDressed (fig. 128.) The lines on the surhiee of 
the segments are transverse, relatire to theii' longer diameter ; the 
endochrome yellow or green. A single chain consists sometimes 
of 1200 to 4000 segments, forming a chain two to tliree inches in 
length; length of frustule 1- 1400th to l-430th. Marine 

The Me'osira lineata (Kiitz.) — Adduced as synonymous with 
Gallionella lineata (E.) is described as having smooth segments con- 
joined in pairs; and, in the illustrative figure, no hnes, save some 
few very delicate ones in the central portion of each frustule, are 
exhibited, like those in Ehi-enberg's drawing. 

G. numnmloides (E.) — Resembles the preceding species ; but each 
frustule has its ends convex, and near each of them a Kne, less 
strongly marked than the central one. The convex ends render the 
segments almost globular ; the latter, also, are smooth ; their con- 
tents yellowish-green when drj^, but brown when recent. Diameter 
l-1700th to l-860th. Sea or brackish water. (P. 14. f. 14, and 
wood cuts.) 



(3 



G. varians = Melosira varians (Ealfs.) — Joints cylindrical, with 
flat ends ; when separate, they rest upon theu" ends and appear like 
coins ; and in such a position, with a high power, delicate radiating 
striae may be seen (as in fig. 131.*) Contents yellow or gi-eenish. 
Size l-2200th to l-480th. Fossil and living; the former constitute 
the principal part of the earthy deposits of white powder used in 
polishing silver plate. 

G. distans. — Segments smooth, short, cylindrical, plane and trun- 
cate on the junction siu-faces ; with two sulci or furrows, separated by 
a more or less considerable interval (distant.) Seg-ments closely 
conjoined ; then- two diameters equal, or that in the length of the 
chain double the other. Diameter 1 -3456th to 1 -864th. 

G. sulcata. — Segments short, cylindrical , about equal in their two 
diametei-8 ; ti-ansversely striped near each jimction-surface, leaving a 
clear central interspace ; surface of end view, M'ith lines radiating 



Naviculacea.'] infusortal animalcules. 373 

from a cleur central spot, and extending to the marginal zone. (P. ;3, f. 
131, and P. 14, f. 26.) Diameter l-860tli to l-GOOth. 

Gaxltoxella moniliformis. — Smooth, large, cylindrical, short ; ends 
truncated cones ; when single, and viewed from the back, they appear 
octagonal ; contents greenish. In sea water ; often confounded with 
G. Uneata. Size 1 -860th. 

G. aurichaJcea. — Segments cylindrical and slender ; their length 
full twice the diameter, with either a single or two perforated rays 
contiguous at the middle ; the ova are green, but, when di-ied, become 
of a golden-yellow colour. Thickness 1 -2300th to l-1720th. In 
fresh water, ditches, and slow streams. 

G. ferniginea = Melosim ochracea (Ralfs.) — Slender, oval, 
convex at both ends ; smooth. In many, perhaps in all chalybeate 
waters, and also in peat water, which contaias a small proportion of 
iron, this is to be found ; it is of the colour of iron-rust, and in 
mineral springs, in which it abounds, is often taken for precipitated 
oxide of iron. It covers every thing under water, but forms so 
delicate and floccose a mass, that the least motion dissipates it. In 
the spring of the year, this mass is composed of very delicate pale 
yellow globules, which can be easily separated from each other. 
They unite together in rows, likeJfehort chains, and produce an irre- 
gular gelatinous felt or floccose substance. About summer, or in 
autumn, they become developed into more evidently articulated and 
stiff threads, of a somewhat larger diameter, but still form a com- 
plicated mass or web, and, either from adhering to each other or to 
delicate conferva, appear branched. In the young condition, when 
examined under shallow magnifiers, they resemble gelatine ; but with 
a power of 300 diameters, the flexible granules are discoverable, and 
with dexterous management, the little chains forming the felt or 
floccose web can be made out. In summer, on the other hand, its 
structure can be observed much more easily and distinctly. Early 
in spring, the coloiu" is that of a pale yellow ochre ; but in summer^ 
that of an intense rusty red, (P. 2, f. 129 and 130.) Diameter 
1- 1200th 

According to Kiitzing, this is not a species of GaUioneUa, but a 
Conferva; it has no true siliceous lorica, as have true Diatomece, 
and the coating of oxide of iron is not an essential element, but 



374 DESCRIPTION OF [Polygastrica. 

merely an incrustation, such as will form on well-known Conferva, 
placed under like circumstances, i. e. in water holding salts of iron 
in solution, which are subsequently precipitated by exposure to the 
air, and converted into the red oxide. 

The same author differs from Ehrenberg, as to the part played by 
the so-called Gallmiella ferruginea in the production of the oxide of 
iron in chalybeate waters, of bog-iron ore, of clay-iron ochi-e, &c. 
For he observes, in many springs rich in h'on, no such orga- 
nism is fotmd, although other Conferva may be present. Conferva, 
however, not peculiar to such habitats, but common in springs and 
ponds generally. 

Mr. Ealfs (Op. Cit. p. 352), however, in part supports Ehrenberg, 
declaring, that though identical with Conferva ochraeea (Dillw}Ti) yet 
"Ehrenberg is no doubt correct, in placing the plant in this genus, 
as the filaments are siliceous and cylindrical." 

Gallionelia midulata = G. vcvrians (Hesse.) — Joints large, often 
wider than deep, surface smooth ; the wall of the testules flexuose 
beneath the integuments ; joints on the side, very finely radiate. 
Diameter l-57Gth. 

G. coardata. — Joints smooth ; its habit is that of G. varians, but 
it is devoid of the strias on the sides. (P. 14, f. 20 and 27.) 

G. grunidata. — The entii-e sxuface covered by dotted transverse 
lines ; when concatenated, these lines arc longitudinal with reference 
to the entire chain ; dotted longitudinal lines in the joints (transverse 
in the chain) characterize G. marcliica, 

G. lirata. — Has the habit of G. granulata, but with stronger lines, 
disposed like the strings of a lyre. United States. 

G. ocidas. — Habit of G. sol, but larger with equal and stronger 
rays, sixty-seven in number, in the circuit of the very smooth disc. 
Diameter 1 -240th. Southern Ocean. 

G. pileata. — '5 omi^ wider than deep, surface smooth; the two 
sutures of the valves much separated, very minutely dotted ; lateral 
disc convex, smooth, often narrower than the connecting band 
(cingulum) or medium-body, hence the hat-like form. Diameter 
1-64 8th. Southern Ocean. 

G. Sol. — Joints narrow, mostly five times deeper than broad, 
nummiform ; disc level, large, smooth ; margin strongly and broadly 



Naviculacea.'] infusouial animalcules. 375 

rayed, with eighty-four rays ; suture of the valves single. Diameter 
l-336th. 

Gallionella TjimpaHum. — Disc broad ; centre smooth ; slender 
margin, minutely striate. Diameter 1-2 76th. Southern Ocean, 

G. sculpta. — Joints large, depth exceeding breadth ; lateral surface, 
with transverse, dotted lines, (which, when the segments are con- 
joined, become, in relation to the entire chain, longitudinal,) densely 
Btriated, and elegantly sculptured ; two sutures about the middle, 
with a narrow interspace. Diameter l-960th. Fossil, Oregon. 

G. (?) spiralis. — Joints small, oblique; breadth greater than depth, 
or equal ; surface with loose, transverse, dotted lines ; chains forming 
curves and spirals. Diameter l-2304th. Fossil, Oregon. 

G. caUigera. — Joints small, smooth, with .the habit of G. distans ; 
breadth double the depth ; median suture single ; a double granular 
mass enclosed within, like G. undulata. Diameter 1-1 728th. Fossil 
in pumice. Island of Ascension. 

G. (?) coronata. — Testules Avith the habit of G. sulcata; the outside 
of the cj'lindcr striated; margin of disc crenate; disc smooth, 
slightly convex, with a cii'clet of granules at its centre like a croAvn 
of pearls. Diameter 1 -864th. Fossil, sea coast of Patagonia. 

G. (?) plam. — Tcstule with tl^ habit of G. sulcata, but with the 
disc of the valves plane, smooth, not radiated nor granular. Diameter 
1-1 152nd. This form may possibly bo but G. sulcata, with its 
markings destroyed (worn smooth) by igneous action. Also fossil, 
Patagonia, in pumice, 

The following species have been found fossil : — 

G. ISfovce Mollandice, G. procera, G. tenerimtna, G. punctata, G. gihha, 
G. Horologium, G. lineolata, G. aspenda, G. liseriata, G. punctiger, 
and G. crenulata = Melosira crcnulata. See plate 14, f. 29. 

Melosira of Kiitzing, and Aulacoseira and Orthoseira of Mr. Thwaites, 
are here introduced as sub-genera, from their alliance to GaUioneUa. 

Sub-genus Melosika. — The following species are derived from the 
valuable papers of Mr. Ealfs, in the Annals of Natural History, 

"M. glolifera (Hervey.) — Frustules (testules, Ehr.) nearlj^ glo- 
bular, with numerous striae, which are most evident on the 
siliceous covering. Filaments affixed by a short stipes (pedicle ;) 



876 INFUSORIAL ANIMALCULES. {Poli/ffagirica. 

frustules in pairs, each with a strongly-marked central line (suture.) 
On marine Algae, Torquay, Hastings, &c. 

" Melosika Borreri (Greville.) — Frustules rather longer than broad, 
cylindrical, rounded at the ends, with a centi'al strongly-marked line 
(suture of the valves, Ehr.) Marine Algae." 

This species much resembles M. nummuloides ; the filaments are 
stouter, the ends less convex, and marked only with a central line. 

" 'K. arenaria {'hiooxe.) — Filaments stout, frustules broader than 
long, with a single central line; junction-surfaces closely united, 
striated. Fresh water ; brownish when recent ; pale green when dried. 

"Filaments much stouter than in any other species, distinct to the 
naked eye ; when rubbed between the fingers, feeling rough like 
givains of sand, whence its specific name. The junction of the 
frustules appears like a dentated surface. (See f. 131 and 199.) 
The characters by which this species is distinguished from M. varians 
have been so clearly pointed out by Mr. Dalrymples, that I shall use 
an extract from his letter, instead of making any observations of my 
own." 

"JJelosira r an'mis (^Agardh) is as clearly GaUionella varians, asMelosira 
areymria (Moore) is OaJlionella varians, (Ehr.) — Still no tyro in 
Natural History could presume, thtt the two were the same species. 
The characteristic difference exists in the well-marked feature of the 
striae at the junction-line of the corpuscles, and which, combined 
with their discoid form, bears a strong resemblance to the milled 
heads of many of the adjusting screws of our microscopes. Added 
to this, is the appearance of radiating lines, seen when the flat sur- 
face of the disc is ia view." 

M. varians (Ralfs.) — Frustules once-and-a-half to twice as long 
as broad, with a single central line ; the ends slightly rounded ; junc- 
tion-surfaces without striae ; filaments very slendci", but varying much 
in thickness ; fragile. Brownish when recent ; becomes green on 
drying. In fresh water rivulets, and ditches. 

The end being rounded, the joints are not so closely united as in 
M. arenaria and M. aurichalcea. Not unfrequently, this species has 
the joints dilated here and there into a globular form ; and in this 
state the central furrow gives the appearance of two joints com- 
bining in the formation of the inflated cells (P. 24, f. 32.) 



Ndviculacea.'] infusorial .VNiMALorLES. S77 

Melostra. aurichdcea {Yiyitz,) — Filaments more slender, and more 
uniform in size ; joints larger, and more closely united : it especially . 
differs in having two central lines, and striated junction-surfeces, 
and in not turning green in drjing. 

Niigeli describes and figures a species wliicli he refers to the genus 
GaUionella ; but it is a doubtful member. His description, however, 
especially that of the self-division, induces us to give it nearly in his 
own words, with his name, (Ray Society, 1848, p. 219.) 

GaUionella (?) (Nageli.) — Eigure shortly cylindrical. Diameter 
.014th to .027th of a line. 

Both the terminal surfaces of the cylinder are flattened, so that, 
when seen sideways, it appears rectangular, with the angles rounded 
off. It is composed of one simple cell, whose membrane is covered 
by a siliceous plate, and its cavity contains chlorophyll granules, which 
lie upon the membrane in two circular bands. (P. 24, f. 26 to 28.) 
Each of these bands occupies one of the two obtuse angles of the 
cylinder, and appears annular from above rectilinear, from the side 
.(See description of Plate 24.) 

In developing, the relative length of the cylinder increasing, a 
septima divides it into halves, (P. 24, f. 28c) which, when com- 
plete, the latter separate as t\^h distinct beings. The nascent 
chlorophyll-granules are either spread equally over the surface, or 
more frequently arranged in radii from the nucleus in the centre ; 
they lie in the course of the currents streaming from the nucleus. 
Compared with a cell of Conferva, or of Spirogyra, all three agree in 
the forming of a septum, in the similarity of their contents, and in 
the depositions of extra-cellular substance. But GaUionella differs 
from both, by the production of an individual from every ceU ; also, 
by the chlorophyll forming two lateral bands, and the siliceous 
extra-ceUular substance an intermediate one. 

" So far as my investigations go, GaUionella, which, according to 
Ehrenberg, posseses a bivalved or multivalved shield, agrees with the 
above-described plant in all essential particulars. The lines, for 
instance, which would intimate a division of the sheU into two or 
more pieces, are the septa by which the cell-division is effected. As 
in the filiform Algoe, these walls at first appear as delicate lines ; 
then, by an increase of thickness, seem two clearly defined lines, and 

c c 



378 DE8CHIPTI0N OF \^Polygagtrica. 

at last present themselves as tAVO lamellae, separated by an inter- 
mediate third line. The perforations which Ehrenberg described, 
I look upon as nothing more than inter- cellular spaces, formed 
between the two new-formed cells and the parent cell. These so- 
called perforations are only visible, therefore, on the two lateral 
borders where the wall abuts upon the membrane. The Confei*void 
Algae exhibit a similar appearance." 

"Under the name Melosira, Kiitzing describes the following addi- 
tional species or varieties of GallioneUa. 

Melosiha mimmuloides. — Large, segments with very finely dotted 
valves, (when dried of a golden colour) ; with evident keels 
(carinae.) Diameter l-840th. Baltic, North Sea, and Coast of 
North America. 

The name of this species would suggest its identity with GallioneUa 
mimmuloides (Ehr.), but Kiitzing finds the synonyme of the latter in 
his Melosira salina, between which and the Melosira just described, he 
indicates a specific distinction. 

M. dubia. — Small ; joints compressed spheroids, smooth. Diameter 
l-1200th. 

M. suhflexilis. — Of middle size ; joints cylindrical, quite smooth ; 
the younger ones elongated ; the aUult shortened, depressed, conjoined 
in pairs ; secondary sides rather convex ; connecting isthmus of the 
conjoined segments short. Diameter l-564th. Friburg. 

M. tenuis. — Very slender; joints cylindrical, quite smooth; long 
diameter one-and-a-half to two times greater ; closely connate ; no 
Bulci. Diameter 1-5 760th. Fossil in the polishing powder of 
Luneberg. 

M. Jurgensii. — Slender ; joints quite smooth, elongate, with two 
slight contractions beneath the siliceous epidermis ; at junction 
surfaces convex, hemispherical, closely concatenate. Diameter 
l-1800th. to l-1200th. 

M. Iletrurica. — Small, joints cylindrical, depth double the width ; 
margin of junction surfaces finely denticulate ; lateral surface -with 
dotted rays. Diameter 1 -3600th. to 1-1 800th. Fossil, SanFiore. 

M. Italica. — Small, joints cylindrical, quite smooth ; long diameter 
(depth) double the transverse (width) ; on secondary sides convex. 
In the mountain meal of San Fiore. 



Naviculacea.'] iNFrsoEiAl, ANiMALCtrLFfl. 379 

Melosira crenulata. — Similar generally to the last, of which it is 
little more than a variety ; but the long diameter of its segments 
is two to four times greater, and the margin clearly denti- 
culate. Diameter 1- 1440th. England, North and South America. 
(P. 14, f. 29.) 

M. Bindsrana. — Another variety ; more slender ; joints variable, 
sometimes ventricose ; length four to eight times the greater ; 
junction-margin minutely striated. Diameter l-6000th. to l-2400th. 
Hamburg. 

M. Americana. — Size moderate ; all the segments united in a 
cylindi-ical tube, separated only by septa; transversely striated on 
the margin, and divided by a median sulcus. Diameter 1 -660th. 
Tropical, America, 

M. decussata. — Slender, joints cylindrical, the two diameters 
nearly equal ; remarkable in being spirally decussated by numerous 
very finely dotted lines. Shores of the Elbe. 

Sub-Genus AxTLACOSEiRA (Thwaites), (Ann. Nat. Hist. 1848.) — Cells 
cylindrical, bisulcate, extremities more or less orbicular, concatenated 
in filaments. 

Aulacoseira differs from Melosim by the deficiency of the centi'al 
line, the place of future fissiparolis division. Each of its frustules 
too, have two somewhat distinct sulci or fossulae (furrows, E-alfs) 
passing round it. The absence of the central line separates Aula- 
coseira also from Orthoseira, from which it is further distinguished 
by the convex ends of its cells or frustules. 

Its typical species is the Melosira crenulata (Kiitz.) the M. auri- 
chalcea (Ralfs); A. crenulata (Thwaites.) Characters those of the 
genus. Sporangium spherical, with its axis of elongation at right 
angles to that of the frustide fi-om which it originated. Around 
the young Sporangium a considerable quantity of mucus is developed, 
by which the empty half-frustules are for some time held attached. 
(P. 24, fig. 33,) represents filaments of Aulacoseira crenulata with 
Sporangia, 

Sub-genus Oethoseiea (Thwaites.) — Cells exactly cylindrical, 
with a central line, connected in cylindrical filaments; internal 
cavities spherical or sub-spherical. 

cc 2 



380 DESCBiPTiON OF [Polygastrica. 

Typical speoies, Meloma Americana (Kiitz.), in Mr. Thwaites 
arrangement, Orthoseira Americana, differing from the following 
new species principally in the ends of its frustules being striated, 

ORxnosEiRA Dicldeii. — Filaments short ; cells quite smooth ; 
other characters those of the genus ; sporangia fusiform. (P. 24, f. 29a.) 

" The filaments of this beautiful species consists generally each of 
from two to four frustules, which are hyaline and perfectly smooth ; 
central cavity filled with dark red-brown endochrome ; Sporangium 
fusiform, marked with numerous annular constrictions, whose 
formation is progressive, and which go on increasing until the 
sporangium is frilly developed (P. 24, f. 296, a filament, the terminal 
cells of which have each commenced to develope a Sporangium ; 
and fig. 29c, a mature Sporangium.) This fonnation thus occui's : 
at the commencement of the formation of a Sporangium, the endo- 
chiome, at the same time that it withdraws from the end of the 
frustule, produced at its centre an additional ring of cell-membrane ; 
and this process continuing to take place at certain intervals, each 
new ring of cell-membrane exceeding in diameter those previously 
formed, produces at length the structure represented in fig. 29c; 
or it may be a more correct explanation of the process to say, that 
an entire new cell-membrane has been developed by the young 
Sporangium at the time each new ring has been formed, and that, 
thus have originated the several chambers into which the ends of 
the Sporangium are divided ; fissiparous division subsequently takes 
place, and sporangial frustules are developed from each half, as 
shown in fig. 29d. This sjiecies was found by Dr. Dichie, in 
a dark dripping cave close by the sea, near Aberdeen, and covering 
the mosses, Hepaticae, as a fine blackish green sand. (.\nn. Nat. 
Hist. 1848.) 

Genus GoNioTHEcnm (Ehr.) — Lorica round, not in chains, having 
a central consti'iction or furrow, each end abniptly attenuate and 
truncate, so as to assume an angular figure. 

This genus resembles Pyxidicula, but has a central consti'iction and 
truncate ends. Fossil. 

G. Roger sii. — Testules in pairs, (binate), smooth ; each dorsally 
sub-quadrate, angular with three vcrticilli ; laterally, elliptic oblong, 



Navieulacea.'] infusorial animalcules. 381 

with two to tlirec median circles ; tlie two tcstules conucctcd by a 
very wide central band, and by their apices ; thc^opening (hiatns) 
on each side the band large, and sub-orbicnlar. Diameter l-588th. 
Vii-ginia Named after Dr. Eogers, the discoverer. 

GoNioTHECiuM (?) dkhjnium. — Testides binate, smooth, trans- 
versely oblong, obtuse ; emarginate at the centre on one side; on the 
other with two tubercles. Diameter 1-1 200th. Virginia. 

G. Gastridium. — Testiiles binate, smooth, transversely oblong, 
ti-uncate at each end, abrubtly dilated at the middle of the ventral 
surface, but not contiguous. Diameter 1 -960th Virginia. 

G. hispidmn. — Testules binate ; each semi-lunar and hispid, with 
a tuberosity (umbo) on the inner side at the centre ; the halves 
contiguous. Diameter 1-1 728th. Vii'ginia. 

G. monodon. — Binate, smooth ; each half linear-oblong, trimcate at 
each end ; outer side uniformly straight, the internal with a median 
tuberosity, not contiguous. 

G. (?) Navicula. — Smooth, small, binate, oblong, and rather turgid, 
ti'uncate at each end. I have not yet observed a median connecting 
tuberosity. Length l-1680th. Virginia. 

G. obsusuni. — Binate, smooth ; each testule transversely oblong, 
obtusely tri-lobed ; no connefecing band. Diameter l-696th. 
Yii'ginia. 

G. Odontella. — Binate, smooth; each testule transversely oblong ; 
dorsally semilunar or gently angular ; laterally oblong, navicular, 
mth three concentric circles ; the halves conjoined by the central 
band and by their apices ; the aperture on each side oblong, con- 
tracted at the middle. Diameter 1 -480th. to l-276th. Virginia. 

G. crenatum. — Specific characters unknown. (P. 24, fig. 10, 
represents apparently a semi-frustule.) 

Genus GEAMiLiTOPnoEA (Ehr.) — Lorica bivalved, prismatic ; self- 
division imperfect ; the cluster ciu-ved ; joints gaping at one of the 
angles. Within are two septa, dividing the body into three longi- 
tudinal portions. Marine. 

The form of this genus recals that of Tahellaria, with two internal 
siliceous folds (^ septa or \'itta^) which are remarkable in being cui'ved 
after the manner of letters. 



882 DESCRIPTION OF \Tolygastnca. 

Xiitzing's desmption is rather diflPerent from the foregoing; " Bacilli 
oblong, tubular, adnate, ultimately connected only by a narrow 
link (isthmus) ; with two constant longitudinal mttce, interrupted 
in the middle, and more or less cui-ved." It is a member of his 
family Talellariece ; tribe Vittatos. 

Geammatophoka Africana. = Navimla Africana, (Ehr.) — Dor- 
sally square or oblong ; laterally navicular and obtuse. Internal 
folds three m each half and undidated. Fossil in the chalk marl of 
Oran ; alive ia sea water, at Tjom. The contents are brownish, car 
golden-yellow-coloured, filling the whole of the iaterior, and only 
leaving a bright transverse band just where the transverse line 
crosses. Length 1 -2300th. to 1 -480th. 

G. angulosa. — Yiewed dorsally, square or oblong; on the side, 
navicular and obtuse ; iatemal fold having many acute angles, 
(plicate) ; this species may be only a variety of the preceding It is 
colourless. Fossil in the chalk marl of Oran. Length, fossil 1-9 10th. ; 
living, Ml 50th. 

G. Mexicana. — Yiewed dorsally, quadrangular; on the side, linear, 
obtuse, the roimded ends being suddenly constricted. Internal folds 
straight in the middle, uncinate at the extremity. Isthmi tumid. 
Alive in sea water, at Yera Cruz, Naples, and Gaeta. Length 
l-960th., little more than twice the breadth. 

G. oceanica. — Dorsally quadrangular; on the side, navicular or 
linear, obtuse ; ends gradually attenuated ; internal folds straight in 
the middle, uncinate towards the ends; isthmi slender; ossil in 
the chalk marl of Oran ; alive in the Cattegat, &c. This creature 
forms long zig-zag bands, which are fi:sed by mucus to Algae and 
SertularisD. Dr. Elirenberg saw some frustules fourteen times 
longer than broad, and others nearly square ; granular contents 
yellow or reddish- brown. Length, fossil l-720th. ; living, l-2300th. 
to l-360th, (P. 14, f. 52, 53.) 

G. undulata. — Dorsally quadi-angular ; laterally linear, with several 
undulations ; internal folds undulated. Colom-less. Alive, Yera 
Cruz. Fossil, Greek marl. Length l-860th. Breadth a third to 
ODe-half. 

G. (fibba, — Quadrangular dorsally ; striated transversely on 



Naviciilacea.'] infusorial animalcules. 383 

each side, and tiiiuid at the middle, with straight intonial 
folds inflected only at the apex. Apices rounded. (P. 14, f. 48. 49.) 
Cuba. 

Grammaxophora Islandica. — Quadrate or oblong dorsally ; na- 
vicular laterally, and striated ; with three internal folds, curved at 
the centre. Iceland. 

G. stricta. — Large, quadrate dorsally, or oblong ; on the sides, 
navicular, lanceolate, and smooth ; internal bands straight, not in- 
flected at the apex. Vera Cruz and North America 

G. Mediterranea. — Oblong dorsally ; laterally navicular and obtuse, 
striated; internal folds four to five, undulating. Length 1 -480th. ; 
on French Coast at Cette ; closely allied to G. Islandica. 

G. serpentina. — Narrow, linear, smooth, six to seven times longer 
than broad; with seven internal undulated folds. Length 1 -252nd. 
Southern Ocean. 

G. marina (Kiitz.) — Smooth, capitate at one end, vitta) (internal 
folds, Ehr.) with one fold turned outward (extrorse) ; on secondary 
side (laterally) linear, apices tapering by degrees, obtuse. Length 
1-1 080th. to 1 -420th. The portions connecting the angles (isthmi) 
of the several fi'ustules, slender. In Atlantic and Pacific Oceans. 
Kiitzing represents this as = Baciilaria Cleopatra and Grammatophora 
oceanica (Ehr,) 

G. tropica. — Large ; margin striated ; in one aspect, linear with 
rounded ends ; vittae with one outward fold; isthmus tvmiid. Length 
l-600th. to l-156th. On marine Alga), Cape of Good Hope. 

G. hamulifera. — Small, smooth ; vittae at each extremity, hooked 
(uncinate.) Length l-2400th. to l-960th. On marine Algae, 
Chili and New HoUand. (P. 16, f. 22.) 

G. gihherula. — Margin transversely striated ; vittae with one fold 
near the apex, laterally lanceolate, somewhat tumid near the middle, 
ends obtuse, isthmi slender. Length 1 -450th. This not improbably = 
G. mediterranea (Elu-.) Bay of Naples. 

G. Anguina. — Large, smooth, vittae with flexuose folds, at their 
inner extremity, hooked. Length l-650th. to l-360th. Among 
Algae. Jamaica, 

Genus Ghammonema. — (Agardh.) — Filaments gelatinous, elongated. 



384 DESCRIPTION OF [Poli/ffasfrica. 

flexible, not fragile ; frustiiles (testules, Ehr.) rectangular, plane, 
not striated, scarcely siliceous. 

In appearance, this genus comes very near to Fragilaria, with 
which it is united by most writers, but its habit is so very different, 
that I am inclined, with Agardh, to keep them distinct. In Fragi- 
laria the filaments are very fragile ; the species do not adhere well 
to paper ; the frustules are siliceous and glass-like, and may be sub- 
jected to a red heat, without any other alteration than the destruction 
of the colouring matter ; and at each end are two, more or less dis- 
tinct, pellucid puncta. 

In Grammonema there is scarcely any silica, in which important 
character it differs from most of the Diatomem, the fflaments are not 
fragile, but highly mucous, adhei-ing firmly to paper or glass, and, 
when dried, appearing like a mere stain ; the application of nitric 
acid, or of a red heat, destroys their form, and I can perceive no 
puncta at the end of the frustules. The filaments are elongated, 
ribbon-like, and composed of numerous fi'ustules, which are longer 
than broad. (Ralfs in Ann. Nat. Hist., vol. 13, 1844, p. 457.) 

Geammonema Jurgmsii = Fragilaria aurea (Hooker). — Filaments 
attenuated, yeUowish-brown ; frustules three to eight times longer 
than broad ; slightly separated at the angles (P. 24, f. 24, 25.) 

Var. fh ) Biatomoides. — Filaments green when dried, and elongated, 
giving a feathery appearance to the plants to which they are attached, 
very mucous, flexible, gradually attenuated ; fi-ustules under the 
microscope nearly colourless ; slightly attenuated at both ends, and 
hence disconnected at their angles ; and as the ends are often also 
somewhat rounded, the margins of the filaments have a crenate 
appearance. In a mass, both varieties are dark brown, but much 
paler if separated in the water. In the first variety the colour is 
but little altered in drying. 

Genus H ALTON YX. — Lorica bivalve, orbicular, not concatenated; 
BUi-face of disc rayed ; number of rays definite, not starting from the 
umbilicus ; no internal septa. 

It resembles Actinocyclus, except in its umbilicus not being radiate, 
or, in other words, the central ocellus is wanting. In like manner, 
Comnodificus differs from Sgwboloplwra in its non-radiant umbilicus, 
wliich is a simple void space. 



Naviculacea.l infusorial animalcules. 385 

Haxionyx senarius. — Surface of testiileswith six rays, their intervals 
occupied by parallel lines ; transversely and loosely cellular, umbilicus 
entire, dotted. Diameter 1- 720th. Southern Ocean j approaches 
Actinocyclus hiternarms. 

H. duodcnarins. — Kays twelve ; umbilicus large, with no dotted 
rays. Diameter 1 -576th. 

Genus HELiorKLXA, (Ekr.) — Lorica of two equal valves, orbicular, 
not concatenated (?); divided intcniaUy into cells by imperfect 
radiating septa, which alternate with a series of external depressions ; 
centre smooth, angular, with large marginal apertui-es, equal in num- 
ber to the rays ; and with closely-set, erect spines, beneath the 
margin, on each side. The surface of the valves appeal's as if over- 
spread with a line granular membrane, or veil. 

Has the habit of Actinoptychus, but differs, like Benticella, from 
Biddulphia, by the lateral spines of the margin connecting the lorica 
in pairs, when young 

H. Iletii. — Testules with six rays and septa, with three radiating, 
loosely cellidar, elevated area?, alternating with a like number of 
depressions, ornamented by decussating fine lines; margin (rim) 
■wide, radiate ; one or three marginal spines to each cellular space, 
and two to fom- to the otMr ai-eee ; umbilicus stellate, smooth ; 
angles not prominent. Diameter 1-S72nd. Bermuda. Fossil. Has 
the habit of Actinoptijclius velatus. 

H. Leeuwenhoekii. — Eight septa and rays ; cellular areoe four, and 
as many alternating lined spaces ; rim wdde, radiate ; marginal spines 
four to the areae of each kind ; umbilical star smooth, tetragonal 
(P. 14, f. 35.) Diameter l-204th. Bermuda; discovered by 
Dr. Bailey. 

H. Euleri. — Ten rays and septa, with five radiating area) of each 
sort ; margin with spines alike in the two ; umbilical star pentagonal, 
smooth. Diameter 1-1 56th. Bermuda. 

H. Selligucii. — Twelve radiant septa, and six radiating and alter- 
nating spaces of the two kinds, spines equal and alike in the two ; 
umbilical star smooth, hexagonal. Diameter l-156th. Bermuda. 

Genus Hemiaulus. — Lorica bivalve, compressed, subquadrate, 
fission perfect, hence not concatenate. Two tubular processes situated 
on each side ; those of one side closed, of the other open ; no con- 
strictions on the sides. 



386 DESCRIPTION OF [Pol^ffastrica- 

This genus has the habit of BiddnlpJiia, but is devoid of the lateral 
constrictions. It has the form of a Pan's pipe, with two orifices on 
one side. 

Hemiaulus antarcticus. — Sub. quadra to, strongly granular, tridendatc 
on each side ; the central dentation shallow and obtuse — the lateral 
ones longer ; two truncate and two opposite ones aciuninate. Dia- 
meter 1-3 14th. (P. 14, f. 54.) 

H. (?) australis, — Strongly granular, tridentate on each side ; the 
central dentations very small (obsolete) ; the lateral rounded. Dia- 
meter l-llo2nd. 

Genus Hemipttchtjs, (Ehr.) — Lorica composed of two equal 
valves, orbicular, not in chains (?). Its interior divided by imperfect 
septa, extending about half way towards the centre, and having no 
depressions on the surface, alternating wdth them ; disc without 
markings, but cro-^Tied by a zone of teeth (denticuli;) apertures on 
the margin not evident. 

This genus diffei's from Actinajyti/cltus by its imperfect septa, by 
the absence of alternating depressions, by the circlet about the centre, 
and by the marginal apertures being obsolete. It seems, by its des- 
cription, to be almost identical with Arachnoidisciis of English 
naturalists. ' 

H. ornatus. — Disc minutely granular ; twenty-nine equal rays, and 
an intervening concentric apparatus of cells. Diameter 1-1 20th. 
Found in Patagonian guano. 

The individuals of this species occur as comparatively very large, 
thin, discoid plates, which exhibit radii upon their surface, connected 
by a very delicate net work, after the manner of the genus Actinop- 
tychus. The radii are like"\vise raised bands, and extend from the 
margin towards the centre, but do not reach it, leaving a broad cen- 
tral disc, traversed by finely-dotted radiating lines, terminating at 
the circlet of teeth at the centre. 

Genus Hemizostee, (Ehr.) — Eound siliceous tubules, occurring as 
so many half circles, contiguous and striated. 

" I (says Ehrcnberg) have contrived this name, to keep in mind 
certaiu singular but not uncommon corpuscles. Are some associated 
corpuscles, like Pyxidicula, the lateral (Hscs of these forms? " 

H. tubulosus. — Testule cylindrical, two to three times longer than 
broad, tiu-gid, trausversel}- annular, resembling a portion of a trachea 



Naviculacea. infusorial animalcules. 387 

(wind pipe) ; the rings semicircular ; the extremities alternately 
conjoined along the centre ; striiie slight, running the length of the 
tubule. The ends of the tubules have not been seen closed by an 
opcrculmn. Length 1 -386th. 

Genus Hercotueca, (Ehr.) — Lorica composed of two unequal 
valves, tui'gid ; membrane of valves continuous, not cellular, gene- 
rally veined beneath an integument, or divided beneath the free setae, 
which are permanent, and assume the place of an integument. 
Hence the corpuscles on the upper and contiguous margin of each 
valve appear as if crowned and enveloped, as it were, shielded, by 
the opposed setoe or membranes. 

The forms of this genus generally resemble those of Galliomlla, but 
are uot spontaneously divisible under a deciduous integument. 

H, mammillaris. — Valves smooth, with the centi'e of the base 
fringed round (fortified), with twenty simple, opposite setae, extending 
beyond a series of mammillce, inserted on the margin itself. Diameter 
1-8 1 6th. Fossil, Bermuda. 

Genus Himantidium, (Ehr.) — It includes several species formerly 
enumerated with Eunotia. Ehrenberg's characters unlcnown ; those of 
Kiitadng are, " Lorica, on transverse section, rectangular; transverse 
striae very fine, and very closely set ; individuals conjoined trans- 
versely and closely, in the form of bands." All the forms are 
motionless, and unattached, neither forming fringes nor films on 
Conferva. They closely resemble Fragilaria, both in form and in 
their mode of concatenation, and single fr-ustules can be distinguished 
from the latter only when seen on their ventral surface, and the 
absence of the central umbilicus thus exhibited. They are of fresh 
water habit, and pretty generally, though not abundantly dislTibuted. 
They also occur in the fossil state. 

H. bidcm resembles Eunotia hidens, but developed in chains. 

H. gracile. — BacUli in chains, with the habit of H. Arms; but 
only half the thickness laterally. Central and Jforth America. 

H. guianense. — Striated laterally ; dilated in the middle ; slightly 
furrowed, and bidendate on the dorsum : extremities attenuate, 
slightly reflex. (P. 15, f. 54.) Cayenne. 

H. MonoduH resembles Eunotia Monodon, except in being concate- 



388 DESCBiPTiON OF [Foli/f/astrica. 

nated. It is large, striated, rather curved ; ends widely rounded. 
(P. 24, f. 16 and 17.) Xorth America. 

HiMANTiuiUii FajJilio. — Striated laterally, much expanded at the 
centre ; subijuadrate, furrowed dorsally, and bidendate ; constricted 
near the obtuse apices. (P. 15, f. 45, 49, 50, 51, and 52.) 

H. jxirallelum. — Linear, finely striated, curved ; dorsal convexity 
and ventral concavity uniform, lines parellel ; apices simply rounded. 
Ehrenberg has seen six wands united. Small specimens resemble 
Eunotia Faba. Length 1 -240th. British guano. 

H. Arms == Eunotia Arcus. — Striated, convex on the dorsum ; 
plane on the venter, constricted ; ends roimded, rather recurved ; 
Btri«B eleven in l-1200th. Length l-480th to l-280th. By its 
imperfect fission it forms chains, as in Fragilaria. Fossil in 
Sweden, and living at New York, Berlin. 

H. pectinale, (Kiitz) = Fragilaria pectinalis (Ealfs.) — Large, very 
finely striated ; apices on secondary side, rather incurved and rounded ; 
the dorsum slightly expanded, plane ; venter somewhat hollow. 
Length of frustule l-300th. 

H. minus. — Small, quite smooth; conjoined frustules forming 
elongated filaments, the dorsum and venter constituting the free or 
exposed surfaces. On fresh-water Algse. Length l-900th. 

H. Suhirolii. — Of moderate size, very smooth; on primary side 
oblong-elliptic, or semi-elliptic ; on secondaiy side, linear, lunate, with 
rounded apices. Length l-384th. (P. 17, f. 13.) 

H. Veneris. — Of middling size, quite smooth, plane on one side, 
convex on the other, with acute extremities. Tiinidad. 

Genus Hyaxodiscus. — Lorica composed of two equal orbicular 
valves, not in chains ; discs not perforated ; destitute of septa ; the 
centre of the disc separable (soliibiLis), valves equal, disciform, with a 
smooth siu'faee. In form, it resembles Craspedodiscus. 

H. lavis. — Smooth, both at the centre and margin, large, discoid- 
Allied to Biscoplea phifsoplea. Diameter 1 -456th. Vii'ginia. 

H. (?) Fatagonicus. — Large, very smooth, flattened; suture of the 
valves remai'kably tumid ; margin of disc sej)arable ; its suture 
slightly sulcate, not denticulate. Diameter 1 -432nd. In pumice, 
fi'om Patagonia. 



Naviculacea.] infusorial animalcules. 389 

In Hyalodiscus Iccvh, the suture of tlu> valves is not tumid ; and not 
the margin oiilj^ but the central part also, of the discs, sepai-able 
(solubilis). Do these two species, therefore, rightly fall together in 
the same genus ? 

Genus Lipaeogtea, (Ehr.)— Cylindrical, utricular, tnineate. Each 
utricle spontaneously divisible transversely through its middle ; 
closed at the extremities, "snth an internal wall, and a spiral filiform 
crest. No aperture evident, but muiute ones may probably be present 
on the denticulated margin ; no internal septa. If occurring 
in chains ? 

This genus, if the individuals be isolated, approaches Pyxidicida ; 
but if they are concatenated, which is doubtful, it becomes allied to 
GalUonella. Inhabit, it approaches very closely to the non- siliceous 
genus of plants, Sjnrogyra. 

L. dendroclioira. — Smooth, ciystaUine, margin of discs denticulated, 
with an internal spiral band; thirteen turns in. 1 -360th. Figure 
utricular, the length exceeding the breadth three to four times. 
Length l-360th. Breadth 1-1 728th. Found on the roots of water 
plants. Its internal contents are green when diied. 

L. cirmlaris. — Smooth, crystalline, margins denticulated, with 
internal annular filaments; tliirteen turns in l-360th. Length l-360th. 

Ehrenherg says, he has not yet determined, satisfactorily, whether 
the preceding are distinct species, or merely varieties of one species. 
Each has a smooth disc, with three central apicuH. 

Genus Mastogonia, (Ehr.) — Lorica (unequally) bivalve, not in 
chains ; valves with protuberant angles, orbicular at the base ; um- 
bilicus unarmed. 

Some forms of this genus were originally placed among the 
Pyxidicula, but clearly diifer by theii' unequal and angular valves, vnth 
radiating veins, and non-ceUular siu'face. They differ, to a like 
extent, also from Actinoct/clus. 

M. crux. — Large, one valve ^dth four crucial angles and rays, the 
other with seven, apices not truncate. Diameter 1 -396th. Bermuda. 

M. qicinaria. — One valve "oath five angles and rays ; apex not trun- 
cate. Diameter 1 -480th. Bermuda. 

Mastogonia Eota. — One valve with six angles and rays; the 
other with seven, apices entire. Diameter 1- 360th. Bermuda. 



390 DESCRIPTION OF {Volygaslrica. 

M. sexangula. — One of the thin valves \vith six angles and rays, 
the other not known ; apex broadly truncate, presenting an hexa- 
gonal area. Diameter 1-1 632nd Bermuda. 

All the above species are very smooth and crystalline. 

M. heptagona. — One valve with seven, the other with nine rays 
and angles, and a truncate apex. Diameter 1 -840th. Bermuda. 

M. Actinoptychus = Pyxidicula Actinoptgclms. — One valve with 
nine angles and rays, the other with thirteen. Apex broadly trun- 
cate, smooth. Rays loose and flexuose. Yirginia. 

M. Oculus Chameleontis = Pyxidicula 0. C. — One valve with eight 
angles and rays, the other unknown. Apices truncate. Diameter 
1-11 52nd. Maryland. 

Besides the above forms, single valves are met with in earth from 
Bermuda, having fifteen to seventeen and nineteen rays ; and, in 
earth from Vu-ginia, with thii-teen, fifteen, nineteen, and twenty 
rays ; and such may constitute other species. 

M. Discoplea. — Small, valves conical, ti'uncate; margin and area 
truncate, with smooth apices ; eighteen to twenty rays and angles. 
Diameter 1-1 152nd. The variety faj with eighteen rays. More 
common, in the pumice of Patagonia ; var. (bj with twenty, more 
rare, in the same substance. 

Genus Mekidost. — The characters of this genus agree, generally, 
with those of Fragilaria, but the frustules being cuneate (wedge 
shaped) form, when concatenated by imperfect self-di\asion, circular 
or spii'al bands. It is closely allied to Navicula, but differs by its 
incomplete self-fission, and its frustules have no central aperture, 
but two placed at their wider extremity ; single wands (frustules) 
are difficult to distinguish from Gomphonema, but the latter possesses, 
besides two terminal pores, a central one also. 

Kiitzing defines this genus, the type of his family Meridie^y 
thus: — 

" Individuals cuneiform, rectangular, prismatic ; closely conjoined 
in flabelliform masses or in spiral bands. Transverse striae strong, 
uninteiTupted." 

The following remarks are from Mr. Ealfs valuable papers (Ann. 
Nat. Hist., 1845) : " This genus, together with Styllaria, Gompho- 



Naviculacea.'] iNFrsoRiAL animalcules. 391 

nema, and Licmophora, form a group (the Stylhria of Agardh) dis- 
tinguished by the ti-iangular form of the frustules, which have their 
smaller ends directed towards a common centre. The frustules in. 
this group have a central and two lateral portions, as in Diatoma and 
Fragihria ; in which genera cuneate frustules are also occasionally 
met with. But in Fragilaria or Biatoma, when two or more cuneate 
frustules are united, the alternate frustules have their ends in oppo- 
site direction, and hence thcii' filaments are linear ; whilst they are 
attached, if at all, only by their basal frastule. In. this group, on 
the contrary, as the smaller ends are in the same direction, they 
point to a common centre, and, when stipitate, each frustule is 
attached to the stipes. 

" Besides the two puncta at the broader end, two others, at the 
smaller end, more obsciu'e, are generally present. The lateral surfaces 
are attenuated at the base, which usually differs somewhat from the 
upper end ; but in the group to which Fragilaria belongs, they are 
similar at both ends, even when the frustules are cuneate." 

Mebidon circidare (Agardh.) — Frustules veiy minute, plane ; on 
primary side (dorsum or face) without vittse ; on secondary side 
(laterally) obovate -lanceolate, with distant, sti'ongly-markcd strise. 
They are partly hyaline, partly of a yellowish-green colour. The 
nearly circular bands occur in a mucous green stratum on mud, 
stones, dead leaves, &c. ; in the spring, in mai-shes, stagnant waters, 
and rivulets. 

This nearly = M. mrnale (Ehr.) — It has two conspicuous puncta 
at the upper end, and from five to twelve along each lateral margin. 
M. vernale. — Striated, wedge-shaped, truncate and dentate at the 
interior (-wT-der) extremity, with two conspicuous puncta. Along 
each lateral margin are from five to twelve vittae (Kiitz), producing a 
beaded appearance. Fig. 177, is a spiral or nearly cii'cular band ; 
fig. 178, a band, with some segments separating, seen on their sides. 
Length of segment or frustule 1-11 50th to 1 -240th. 

M. (?) panduriforme. — Sinuous, wedge-shaped, of the form 
of a violin. Length 1 -430th. Kutzing says its form is that of 
Gomphonema acuminatum. 
Meeidok Zincheni. — Primary side with vittae ; secondary side. 



392 DESCEIPTION OF [Poli/ffasfrira. 

obovate-lanceolate ; the filament formed is curved, or nearly 
straight. Length l-420th (P. 16, f. 21.) 

Meridon (?) Ovatum (Agardh.) — "Frustules ovate, combining 
to form a cellular band." Kiitzing mentions this as a doubtful 
species, described by Agardh. 

M. comtrichim (Ualfs, Ann. Nat. Hist., 1843, p. 458.) — Lateral 
surface constricted below the apex, ti'ansversely striated, the ends of 
the striae forming puncta along the margins of the front view. 
Frustules united together in a chain so as nearly to form a circle, 
but are not arranged on a level plane, as M. vernale, standing nearly 
erect, after the manner of the staves of a tube. They agree in size 
and fonn, and in the puncta with M. vernale, but differ most remark- 
ably in the constriction below the apex. Found by Mr. Jenncr at 
Tunbridge Wells. 

Genus Monogeamma (Ehr.) — Lorica -s^dth transverse pinnules 
(stiite), and a central transverse linear space, but only traversing one 
half the -width (a semi-crucial umbilicus) ; with tln-ee ventral and 
two dorsal apertures. 

2I()no(jramma, therefore, equals Stauroptera, but with a semi- 
crucial umbilicus ; it has also a resemblance to solitary Achnanthes, 
with terminal apertures. y 

Species unknown. 

Genus Nayicula (Bory St. Vincent.) — The little skip Animalcules 
derived their generic name from the resemblance in form of the 
many species to a weaver's shuttle. According to Ehrenberg, it 
comprehends those members of the family Bacillaria which are 
unattached, and have a simple bivalved, or multivalved lorica. 
They occur single, or in pairs, but are never united in the form of a 
chain. The lorica of Navicula is a closed, mostly-four-sided, hard, 
and glass-like little bivalve case {testula hivalvis), which, in drying, 
often separates; when lightly pressed, it breaks or divides either 
into two or four longitudinal parts ; sometimes the angles are pro- 
vided with a short rib, distinctly ftirrowed, the lorica then separates 
into four equal parts ; but in some cases the two rows of ribs 
arc not visible, the two halves of the lorica being obliquely fun-owed ; 
it then separates into two parts. By heating the body upon platiua- 



Naviculacea.'] inpusortal animalcules. 893 

leaf, the organic matter is consiiincd, and tlie siliceous lorica left 
clear and free. The gelatinous and diaphanous body of these ani- 
malcules occupies the whole of the interior of the lorica, and has, 
near the centre, a sharply circumscribed colourless bright spot. In 
N. fulva, an organ of locomotion has been seen by Ehrenberg, which 
he describes as a fleshy, undivided sole-like foot, proceeding from the 
central opening, and similar in appearance to the locomotive organ 
of snails. The side of the body where this foot-like process emanates, 
is called the ventral surface of the animalcule. This foot not only 
answers the purpose of allowing it to creep, but the animalcule, 
when at rest, can draw objects to it, and push things away by it. 

"VMiether the two openings on the ventral surface are mouths, and 
the two on the back apertures for respiration, is undecided ; but the 
opening on the back, opposite the central ventral opening, is sup- 
posed by Ehrenberg a sexual one. No direct demonstration of the 
nutritive apparatus has yet been effected by using coloured food, 
though numerous scattered and coloiu'less vesicles are to be seen 
within the bodies of several species, which indicate polygastric 
structure ; but what Corda took for an alimentary canal (in Pharyngo 
glossa) was merely the dark central longitudinal furrow of the lorica. 
This genus is more complex in its structure than the two preceding ; 
and many consider these beings as animals. The green, yellow, and 
brown colouring matter in their interior, supposed to be ova, occurs 
in the form of broad plates or fillets, fi'om two to four (8 ?) jointed 
together in the middle. These plates take the exact form of the 
interior of the shell, filling the cavities of the flutings, furrows, or 
striae. In many species, two or four round vesicles are seen, which, 
although they are not changeable in form, or contractile, yet are 
sometimes present and sometimes absent, ana are probably analogous 
to small seminal glands. Many Navimla multiply by spontaneous 
self-division, in which case it is invariably longitudinal, and dorsal, 
or lateral ; the division taking place beneath the hard epidermis, as 
in GaUionella and Achnanthes, and the lorica separating afterwards. 
It is seldom in this genus that a second self-division commences 
before the first is complete and separation takes place ; indeed, species 
whose individuals separate into four, shoxild be placed in Fraxjilaria. 

D D 



394 DESCRIPTION or {Volygasttica. 

The folio-wing obscn-ations are from more recent investigations of 
Ehrenberg : — 

In tbe small pools left by the ebb of the tide near Ciixhaven, he 
remarked numerous little bodies, apparently similar to KavicuU, 
' Surirella elcgans, and S. striatula, but which, from their compara- 
tively very great size and structure of lorica, were easily distinguish- 
able from them upon closer examination. One of these ribbed oval 
glass-like creatures, which belonged to the genus Naricida, was, 
besides its size, remarkable for its great mobility, and Dr. E. was 
enabled to investigate its system of locomotion much more satis- 
factorily than he had hitherto done in any member of the genus. 
This organ he states was very different, both in form and size, to what 
he had before noticed. Instead of a snail-like expanding foot, long 
delicate threads projected where the ribs or ti'ansverse markings of 
the shell joined the ribless lateral portion of the lorica, and which 
the creature voluntarily di-ew in or extended. An animalcule 1-1 8th 
of a line long had twenty-four for every two plates, or ninety-six in 
the total ; and anteriorly, at its bread frontal portion, four were 
visible. The openings for the pm-poses of nutrition appeared to be 
at the extremity. Whether these organs were supernumerary, and 
existed along with cirrhi, &c., and the flat snail-like foot, which the 
rest of the Nmiculm possess, could not be determined. Longitudinal 
clefts at the broad side of the shell were not present, but as many as 
ninety-six lateral openings for the exit of the cirrhi were perfectly 
distinct. It is probable this creature may form the type of a special 
group of the BacilJaria. Of one thing Dr. E. is convinced, that the 
Kavicula in general are very differently constituted indi\-iduany ; 
thus, in some cases, the six round openings in the little sheU are dis- 
tinctly visible, whilst in others, clefts, which in some cases gape, 
and are unprovided with circular openings, are all that can be 
made out. 

The fleshy, undi-\dded, sole-like foot, Ijang close upon the lorica, 
described by Ehrenberg in some of the large forms of Naviculce, has 
not been observed by any other microscopist. Kiitzing says he has 
failed to discover this locomotive process, though he has searched 
most narrowly after it. Neither, again, have Ehrenberg's views, re- 
epecting the presence of locomotive ciha, capable of being protruded 



^aDlcutacea.'] inpitsohial ANiMALCUtES. 395 

and retracted through openings in the lorica, met witl\ any support 
from other naturalists. Some few, indeed, have seen hair-like appen- 
dages to the lorica of Surirella Gemma, and also to that of some 
other JJiatomece, but none have witnessed any power of motion in 
them, and their presence would seem almost accidentaL (See note 
on Surirella Gemma, by the Eev. W. Smith, p. 404.) Dujardin 
affirms, as the result of most minute and painstaking investigations, 
that foot-like processes, and moving cilia, have no existence in any 
Navivida. 

Ehrcuberg's assumption, that the clear vesicles, often seen in the 
interior of Xavicuh, are seminal vesicles, is recognized by no other 
naturalist. Kiitzing says they are oil-vesicles, without any true 
enclosing wall, ccciu'ring at hazard, capable at -duj time of coalescing 
on approximation, and distributed irregularly, and in varying abmi- 
dance, amid tlie contained amylaceous clilorophyl of the lorica. 

In seven species of Kavicula, Ehrenberg proved, to his mind, the 
stomach-like nature of tlie globules seen in thcii" interior, by the 
supposed visible imbibition of an artificially coloured solution in 
which the Naviculce were placed. These so-called stomach vesicles 
vary in number and position in the same species ; their distribution 
is, for the most part, quite irregular, and sometimes they are entirely 
wanting. This last circumstance, Kiitzing remarks, is opposed to 
the belief in then- digestive functions, for surely such important 
organs as stomach should never be absent. Moreover, other ex- 
perimenters have failed to get any colouring matter introduced 
within the lorica of Naviculce. 

lioth Kiitzing and Ehrenberg coincide in the opinion of the 
■ circular spots of the lorica being actually pores; and the former 
describes them as furnishing an exit for the gelatinous substance 
which is found to invest some Naviculce, and is especially remarkable 
in the case of those genera having, as Ehrenberg terms it, a double 
lorica, such as Schizonema. In opposition to this notion of the lorica 
being porous, Schleiden gives engravings to prove that the apparent 
openings are but depressions of the sm-face, and have no communica- 
tion with the interior. Dujardin affirms, on the contrary, that they 
are elevations (see p. 399, and Plates 19 and 20.) 

The lorica of Navicula, as of other Bacillaria, is generally con-" 

D D 2 



396 DESCEiPTioN or lPo7i/(/astr{ca. 

eluded to be composed of two lamina, or an outer and inner mem- 
brane, the distance between the two being its thickness. Ehrenberg 
inclines to the belief that the striae and pinnules are but furrows 
upon or within the lorica ; but Schleiden represents them as clefts, 
penetrating between the outer and inner lamina, or lamella (P. 18, 
f. 1 to 6.) In this matter, too, Scbleiden is supported by the inde- 
pendent testimony of the Eev. "W. Smith (Ann. Nat. Hist., vol. 7, 
1851, p. 8) who describes thecostoe of Surirella, &c., as tubes passing 
between the siliceous valves and the inner membrane ; but to this, he 
adds, " that those canals communicate with the exterior by a series 
of perforations," (p. 401.) 

The clear longitudinal bands or iillets, seen in many JVctvicnIa, are 
also held by Schleiden to be clefts like the pinnules (P. 18, f. 2, 3, 5) 
but, by Dujardin, they are considered to be elevations or thickenings. 

The prevailing opinion is, that the frustule or lorica of Kavicul^, is 
inherently one-celled, without any internal subdivisions. The double 
contour, which denotes the thickness of the wall of the shield (lorica) 
may be seen to terminate suddenly both above and below." " This," 
says Schleiden (Principles of Botany, translated by Dr. Lankester, 
1849, p. 594), "clearly shows that a passage exists from the top to the 
bottom of the shield." This structure is still better shown by an 
oblique section, which may be obtained by taking some of the sili- 
ceous earth of Erbsdortf, and mixing it with mucilage, and, before 
it is perfectly hardened, cutting off delicate plates with a razor 
(P. 18, f. 4.) 

Now it has been proved, that cells, whether animal or vegetable, 
have, at some period of their existence, within them, mostly seated 
on one part of their wall, a small circular body, called the nuclens or. 
cytoblast, and which Schleiden conceives to precede the cell itself, 
and give origin to it. Among the Algae, till of late, this organ was 
known only in Spirogyra, biit Nageli (Pay Society, 1845, p. 221) 
affirms that, " in a species of Navicula, in the centre (whether lying 
on the membrane or free, I know not), is a nucleus with a nucleolus." 
(See genera Gallionella, and p. 377.) 

This genus Navicuh, from recent researches, now numbers so many 
species, that, for convenience of description and reference, it has 
become necessary to break it up into several sub-genera. Ehren- 



Naviculacea.] infusorial animalcules. 397 

berg in his great work, (the number of species being then compara- 
tively few,) contented himself by making two sub-genera, Navicula 
and Surirella, the former without, the latter with, transverse striae. 
To these two he has subseijuently added rinmdaria, Stauroneis, and 
Stauroptera, making in aU five sub-genera of what is called the genus 
Navicula, but which might, indeed, be called rather the family 
Naviculea. 

Moreover, not a few species, enumerated in 1838 with Navicula, 
have been since transferred to other genera — themselves mostly new. 

In framing the characters of his sub-genera of Navicula, Ehrenberg 
has had recourse to the circumstance of the presence or absence of a 
median aperture or umbilicus, and its form, in conjunction with 
that of the presence or absence of transverse striae. Where, on the 
other hand, that author has entirely transposed species from Navicula 
of 1838, to other genera, he has been especially guided by the 
number and disposition of the apertures, coupled vnth the form of 
the lorica, and its occurrence or non- occurrence in a concatenated 
manner 

The following plan represents the sub-genera of Navicula, with 
their mutual relations and distinctions (exclusive of the sub-genus 
Pleurosigma of the llev. W. Sffuith, — appended.) 

Without a eentral aperture Surirella. 

/ Smooth, or longitudinally ) ^t ■ i 
) striped I Navicula. 

Navicula. ■{ ( Umbilicus j 

I rouuded V Transversely striated Pinnularia. 

With a central I 
aperture oi •< f Smooth or longitudinally ) „. 
umbilicus. 1 striped ( Stauroneis. 
I Umbilicus -^ 
L crucial | Transversely striated Stauroptera. 

This sub-division of Navicula is not approved of by Kiitzing, so far 
as it rests on the circumstance of the presence or absence of trans- 
verse strioe, since, as he affii-ms, these striae are variable, and cannot 
be used as generic characteristics. 

But this writer employs, unhesitatingly, in defining genera, the 
characters to be drawn from the presence or absence of a median 
aperture, from its form, and from the position and number of other 
apertures, as also from the figiuc of the lorica on a trans /erse section, 
or viewed end-ways. 



398 DESCRIPTION OF [Pulj/jasfrica. 

Kiitzing would appear, indeed, to assign a higher importance to 
the presence or absence of an umbilicus than ercn Ehrcnberg, for he 
has constituted Sun'rella, with some other genera, into a family 
Surirellcce, totally distinct from the family Kaviculece ; in fact, Suri' 
rella and Kavicula belong to two different orders ; the former, 
devoid of an umbilicus, to tho AstomaticecB ; the latter, j)0ssessing an 
umbilicus, to the Stomaticce. 

According, therefore, to the foregoing opinions, Kiitzing retains 
the transversely striated and umbilicated Pinnidaria with the smooth, 
umbilicated Kavicula; as likewise the smooth Stauroneis with the 
striated Stauroptera. 

A still more remarkable plan, pui'sued by the author just named, 
is, the including in his family Kaviculeai those peculiar organisms, 
having the outward general figure of minute, branched, or tufted 
Algse, but intimately composed of innumerable, mostly minute, 
na\dcula-likc bodies, enveloped in a gelatinous investment or thallus 
and which Ehrenberg described as Bacillaria with a double lorica. 
With these compound organisms, indeed, a relation is sometimes dis- 
played by species of free Navicula, which are suiTounded by more 
or less mucus ; but the first-named beings seem to form a more 
natural group by themselves. To ti;ace an analogy, they bear the 
same relation to the free, isolated Navicula, as do the polj^paries of 
coral, or other aggi'cgatcd polypes, to the simple polj-pes ha-ving an 
individual or isolated existence. 

This point is partly conceded by Kiitzing, who divides his family 
Navicula into two sections : — .\'iz. (a.) True Naviculem, and fb.J 
ScJdzonemc(S. In the first section he locates the following genera : — 
viz., Navicula, Amjilnpleura, Ceratoneis, Stauroneis, Amjyhiprora, 
A/tiphora, and Diadesmis ; in the second, Frustulia, Berkeleya, 
Ehaphidof/loea, Homoeocladia, Scldzonema, Microniega, and Diclcieia. 

Surirella, as before remarked, gives name to a distinct family in 
the system of Kiitzing — Surirellcce; which, in addition to that genus, 
compreliends Camptjlodiscus, Bacillaria , and Synedra. 

On the sub- division and structural peculiarities of this great genus 
Navicula, the Eev. W. Smith, in a recent paper (Ann. Nat. Hist 
Jan. 1852), has the ensuing remarks : — 

'* I ghall restore the genus rinnularia of Ehrenberg, rejected by 



Navicidacea.] infusoeial animalcules. 399 

Kiitzing, uiul adopt the term Pleurosigma, as descriptive of another 
group. The genus Navicida of Kiitz., and other writers, will then 
be resolved into three, whose characters may be given as follows : — 
1. I'leurosigma. Valves convex, sigmoid striated; striae resolvable into 
dots. (P. 20, f. 17, 18, 19.) 2. Navicula. Valves convex, lanceolate 
or elliptical, smooth or striated ; striae resolvable into dots. 3. Pinnu- 
laria. Vahes convex, oblong or elliptical, ribbed or pinnated with 
distinct costae, not resolvable into dots. ..." In Pleurosigma, the 
resolution of the striae into their constituent beads becomes a task of 
extreme difficulty, and has, from this circumstance, been very 
generally adopted by microscopists as a means of testing the object- 
glass of a microscope. The presence of striae, on the valves of 
Pleurosigma and Xaricula, may be known, even when the power em- 
ployed is insufficient to detect lines, by the colour of the dessicatedfrus- 
tulcs viewed by transmitted light. This colour diifors in each species ; 
it arises from the refraction of the rays j^assing through the siliceous 
plate, and its shades depend on the direction of the striae, and their 
distance from each other ; its aid may therefore be evoked in the 
discrimination of species, and will sometimes be found the most 
facile and certain means of identification. 

" In the Xacicuhce generally, each valve is traversed by a median 
line, across which the striae do not pass. The centre and extremities 
of the line are somewhat enlarged, and these enlargements have 
been regarded by many wi'iters as openings in the siliceous plates. 
I have never been able to satisfy myself that such openings exist, 
and am disposed to regard the line itself, and its enlargements, as 
peculiarities Kttle connected with the essential structure or functions 
of the cell. More important, in a structural point of view, is the 
form of the connecting membrane, which, in Pleurosigma, consists of a 
narrow ring of silex, and which in no period of its growth appears to 
have any very considerable development. The consequence is, that 
the frontal (lateral, Ehr.) view of the frustules is uniformly of a 
linear, or, when the convexity of the valves is considerable, of a 
linear lanceolate form, while in Navicula and Pinnularia (P. 1 8, f. 2, 
20, 22, 23), as the connecting membrane is often more fully de- 
veloped, the front -vdew of their frustules is frequently oblong or 
quadi'ilateral. Two much importance must not, however, be attri- 



400 DESCEiPTioN OF IPoli/gastrica. 

buted to this aspect of the Diatomaccous frustules, as its foiin greatly 
depends upon the stage to Avhich self-division has arrived, and may 
vary from linear to oblong, or from very narrow to very broadly 
lanceolate, in the same individnals. In p. 20, f. 13, is an illus- 
tration of multiplication by self-di\dsion in PJenrosigma. That by 
this mode Naviculece multiply to a surprising extent, is evident, from 
the circumstance of so great numbers being found together nearly all 
of exactly the same size ; but it is also certain that they, like some 
other Diatomece, have a specific mode of reproduction, since we often 
find fi-ustulcs in various stages of growth, as is evident fi'om the 
diversities of their size, (P. 19, f. 7 and 9 ; p. 20, f. 1 to 3, 9 to 12), 
and from the greater delicacy of the striae in individuals of the same 
species J circumstances which are incompatible with the process of 
self-division, where the half new fi'ustulcs must of necessity be pre- 
cisely counterparts of the old. The mode in which the genninative 
power is renewed, when exhausted by self-division, will probably 
be found to be a process analogous to that of conjugation in the 

DesmidietB, and in some of the Biaiomece The figures of Pleuro- 

sigma, in p. 19 and 20, are di-a\\Ti by the camera lucida to a scale of 
400 diameters." 

In Ehrenberg's an^angements, Naincida gives name, and is the 
type of the section Nmicidacea, of the great family BaciUaria, although, 
the characters of many of the forms introduced are far removed from 
those of the genus Narmda, and any affinity with them scarcely 
traceable. 

The only connecting link between the genus Navicula and many of 
the so-called Karicuhicea, is the siliccoiis nature of the lorica ; 
however, Navimla has close affinities Avith a large number of other 
genera ; and each of its sub-divisions has also its own special 
relations: what these severally are is pointed out under the head of 
each genus. Still it is veiy difficult, oftentimes, to assign to its proper 
genus each navicula-shapcd lorica which may be met "v\dth, especially 
when but one or two at a time occur, and then only probablj^ one 
surface presented to view ; or when the right portion is to be deter- 
mined by the fact of its attachment or non-attachment, and only 
detached frustulcs arc to be had, either from accident or li-om their 
occurrence, in a fossil state. 



Naviculacea.'] inftjsoijial animalcules. 401 

The difficulty is illustrated by the fact, that of the forty-live 
species of Nmicula, described after Ehrenberg, in the former edition 
of this work, ten have been since transferred, by that most accurate 
observer of species, to other distinct genera, apart from the many 
re-distributions he has made among the several sub-genera. 

Kiitzing separates several species from Kavicida, by reason of their 
being symmetrical ; that genus being peculiar in always having a 
symmetrical lorica, — i. e., one equally developed on each side the 
central umbilicus. Those species so removed, arc included in the 
genus CymleJla. 



Sub-genus Sijiiirella. — Striated ; no umbilicus ; in both these 
circumstances difiering from Kavicida; and, in the latter of the 
two, from Pinnularia. The following additional characters and 
remarks are from the recent valuable contribution in the Annals of 
Natural History, by the Rev. W. Smith. (1851, p. 7.) " Valves 
concave, with a longitudinal central line, and margins produced 
beyond the suture (winged.) Friastules free, solitary, or, when under- 
going self-di'vision, in pairs- The concavity of the valve, their 
winged margins, and the longitudinal central line, which wants the 
central depression (umbilicus.), so conspicuous in the Naviculece, are 
characters which sufficiently distinguish Surirella from all other 
genera." 

Mr. Smith has detected alse in six species (S. hiseriata, splendtda, 
gemma, fastiwsa, craticula), and he believes them present in all. It is 
only on an end view of the valves, but rarely to be obtained, that the 
alse can be clearly seen. 

"The costae, so conspicuous in several species, as well as in Campy- 
lodiscus costatus and spiralis, appear to be caxised by canals or tubes 
passing between the siliceous valves and the inner membrane of the 
cell ; these canals commvuiicate with the exterior by a series of 
perforations, along the suture or line where the connecting membrane 
imites Avith the valves. Accepting the Diatom as a vegetable 
organism, these tubes will be regarded as analogous to the inter- 
cellular passages, and the exterior perforations will perfonn the 
office of the stomates of the leaf. (At most, these perforations can 
have but a remote analogy with stomates, for these organs are peculiar 



402 DESCEIPTION OF \_Poli/<jastrica. 

to air broatliing plants, and absent in submerged ones. In S. bine- 
riata, and S. splcnd'da, the costse or undulations caused by these tubes 
are continued to the margins of the alse, and gives a singularly beau- 
tiful appearance to the front view of the frustule." 

The so-called costae are otherwise called, by Ehrenbcrg, transverse 
Btriaj or pinnules ; but in the species named, as well as in others, the 
strice are not mere single lines, but have a double contour, and an 
apparent prominence or depression. 

SuKiiiELLA Lihrile. — Elongate, oblong, slightly constricted at the 
middle ; ends sub-acute, rounded or apiculate ; the last condition is, 
however, more common with young or smaller specimens. Transverse 
Btria3 eight in 1-1 200th. Lateral aspect linear, oblong, with rounded 
truncate ends, divided by a central clear line, on each side of which 
is a wavy band having about six undulations. Group 155, repre- 
sents both aspects. Alive at Gravescnd and elsewhere ; fossil at San 
Fiorc, Mexico, &c. 

S. striatula. — Ovate dorsally, with small aloe ; striae strong, curved ; 
ends rounded (fig. 137); laterally (on front view. Smith) cuneate 
and elliptical ; ends rounded, very broad, (fig. 138); alae small; striae 
eight to thirteen in 1-1 200th. This form was discovered by Dr. 
Surircy in 1826, and preserved alive foj' eighteen months. It is veiy 
transparent and colourless ; its motion, when observable, is slow. 
Alive on the English and French coasts; fossil in Bohemia. Length 
1 -3450th. to l-60th. 

S. tmdulata=^Denticida constricta (Klitz.) — Striated, large, elliptical, 
ends rounded; laterally, linear and truncate; margin prominently den- 
tate, with a ficxuosG baud running longitudinally on each side. 
Striae four in l-1200th. (fig. 149 represents an oblique view.) Found 
amongst Oscillatoria. Length 1-2 10th. 

S. constricta = Denticula undulata (Kiitz.) — Striated, large, oblong, 
sliglitly constiT-cted at the middle on the ventral surface ; ends obtuse, 
truncate; striae three to four in 1- 1200th. Laterally oblong, extre- 
mities dilated, rounded; the margin dentate. Alive at Berlin. 
Length 1-2 10th. 

S. constricta (Smith) — Frustules on front view oblong, with 
rounded ends ; outline on side view elliptic-lanceolate, each margin 
having a central sinus ; alaj distinct ; costic numerous, delicate ; 



Naviculacea.'] infusoeial animalcules. 403 

medial lines inflated in the centre. Average length of A'alvc 
l-300th. ; breadth at constriction 1 -850th. In brackish water near 
Lewes. 

The front view of this species bears a close resemblance to tlie 
Bame aspect in S. hiseriaia, (Smith) differing only in the appearance 
of the costoe, which, in the present, assume the character of striae 
rather than ribs. On the side view the constriction of the margins, 
the inflation of the central fuiTOW, and line-like appearance of the 
costce, afford sufficiently distinctive characters. The superficial 
observer, regarding the side view only, might indeed confound this 
species Avith immature specimens of Oymatopleura soha, but a slight 
examination shows that the resemblance is one of outline merely. 

This seems an independent species, but it is unfortunate that its 
discoverer has applied to it a name ah-eady in use to designate 
another. 

SmuTRELLA splcndida. — Striated, on front \dew, ovate-oblong ; ends 
rounded (fig.150, 151, and 152). Transverse stritc sti'ong, rib-like ; al» 
large ; striae, two in l-1200th. "In June, 1837," observes Ehrcnberg, 
"was the last time 1 saw this species. The specimens resembled 
Turpin's SurireUa striatdla, found in the sea at Havre, but were, 
nevertheless, distinguishable jDy their form and stripes. I saw them 
move veiy often. The plates of the ova clusters are toothed, and of 
a golden yeUow colour-. ' ' Length 1 -2 1 0th. to 1 - 1 00th. Found both 
living and fossil. 

^. (}) bifrons. — Striated; resembles the preceding, but both ends 
of the lateral sm-face are acute, and those of the venti-al, truncate. 
Three-and-half striae in 1-1 200th. Common; living amongst Oscil' 
latoria, and fossil in the Isle of France. Length 1-2 10th. to 
1-1 00th. 

This species = S. liseriata (De Brebisson), the name adopted also 
by the Rev. AV. Smith, who observes, in his note on this form, " In 
living specimens I have noticed a circulation of the granular contents, 
analogous to that which is seen in many of the Besmidiece, and in the 
cells of the higher order of water-plants ; a further proof that it is 
a single cell, and a presumptive evidence of its vegetable nature." 

S. folium. — Ovate, turgid and obtuse, slightly compressed, central 



401 DE8CKIPTI0N OF {JPolygostnca, 

aperture not present; striiB narrow, twenty-four in 1-1 150th. 
Leiigtli 1 -540th. 

SuKiKELLA Gemma. — Ovato-oblong, hxrge, turgid, central aperture 
not present ; striaj slender, sixteen in 1 -1 150th. Alive at tlie mouth 
of the Elbe, and in various tidal harbours of England. Length 
l-290th. to 1 -220th. 

S. Gemma. — Mr. Smith says — " Erustules on front view wedge- 
shaped, with rounded ends ; side view ovate-elliptical ; alae large ; 
costse small, unequally distant ; surfiice of valve distinctly striated. 
The striae are made out with difficulty on the dry valve after burning 
or maceration in acid. Its costfe are linear, unlike those of S. striata, 
craticula, constricta, &c. (P. 15, f. 2, 3, and 4.) 

" It was in connection with this species, that Ehrenberg records 
the presence of cilia, extending from the aperture of the costae, 
vibrating with rapidity, and being extended or retracted at intervals. 
(P. 15, f. 3 and 4.) The presence of delicate hairs, apparently on 
all parts of the frustule, may often be detected ; and I have noticed 
them on nearly every occasion when I have gathered this species, but 
in no case have I been able to perceive any motion in such hairs, 
and concluded, before meeting -ndth Ehrenberg's remarks, that they 
were merely a parasitic growth, the mycelium of some other algae. 
I have noticed similar appendages to other Biatomacece, but in every 
case devoid of motion." 

S. Clypeiis. — Large, ovate, obtuse, with nine very broad pinnae in 
l-276th. Marine. Length l-276th. 

S. craticula. — Lanceolate, with large aloe ; apices on the dorsal 
aspect acute; on the lateral, truncate; and figure oblong, with 
centre slightly inflated; pinnules seven in l-1200th. Length 
l-288th; smaller than S. hifrons; costoe fewer, and those divergent. 
(P. 15. f. 19 and 20.) 

S. fastuosa. — Larger, elliptic ; alae small ; pinnules dilated 
gradually, eighteen on each side, in l-360th, which is its length ; 
central portion of valves smooth ; apertures of costal tubes large. 

S. lamella. — Large, lamellar, ovate-lanceolate, slightly keeled ; 
striated only on its extreme margin, the whole central space being 
granular; laterally narrowly linear, and truncate. Length l-216th. 
to 1-1 80th. 



Naviculacea.j infttsohial ANiMAtcuiii:s. 405 

SxJHiRELiA rohista, (foiTnorly associated with Navicnh hifrons.) — 
Large, elliptic, elongate, with two very strong pinnules in l-1200th. 
Length 1-2 16th to 1-1 20th. Fossil in the siliceous meal of Finland. 

S. Testudo. — Large, ovate, obtuse, with twelve slender pinnules 
in its length, which is l-288th. 

S. Campylodisms. — Small, ovate-elliptic ; ends equally rounded ; 
flexuose, like Carnpulodiscus ; margin striated, with ten to twelve 
pinnules on l-1200th. Mexico. (P. 15, f. 12, 13, 22, and 23.) 

S. decora. — Large, elongate, sides straight, extremities equally 
acute; pinnules small, four to five in l-1200th. I^oi'th America. 

S. elegam. — Large, broad ; surface with very minute dots ; ends 
subacute ; pinnules four in 1-1 200th. 

S. eughjpta. — Smaller, ovate, oblong, smooth ; one extremity more 
tapering than the other, but both obtuse ; pinnules seven in l-1200th. 
Mexico. 

S.fexuosa. — Larger, flexuose; pinnules four to five in l-1200th 
(only a fragment examined) ; approaches Camj^i/Iodiscus. Mexico. 
(P. 15, f. 11.) 

S. Ilicrocora. — Yery small, smooth, lanceolate ; ends short, acute, 
equal; pinnules marginal, ten in 1-1 200th. Cayenne, Mexico. 

S. myodoti. — Small, nan-ow", elongate, rather curved; ends rounded; 
pinnules small, closely set, and giving the margin a toothed appear- 
ance, six to seven in l-1200th. Mexico, 

S. ooplmna. — Larger, view on the sides ovate, plicate-undulate; 
one end widely rounded, the other tapering, but obtuse ; there are 
five transverse but obscure plicae (undulations) ; pinnae small, six in 
1 -1200th. Falaise and Mexico. 

S. Peruviana. — Yery large, but narrow and elliptic-lanceolate; 
extremities equally obtuse ; pinnules very small, faint, about twelve 
in l-1200th. Peru. 

S. Begiila. — Small, linear, sides straight, with six bands, ends 
cuneate ; pinnules ten in l-1200th; almost obsolete. Mexico. 

S. (?) paradoxa. — Small, and not pinnate on the navicular sides, 
linear-elongate, elliptic, and ends rounded. Length l-576th. 
Caltanisetta, Sicily. 

S. rhomloidea. — Smooth, not pinnate on the sides, which are rhom- 
boid; ends obtuse on back, linear. Length 1- 744th. Caltanisetta. 



406 DESCRIPTION OF [Pol^gastrtca. 

SuEiErxLA Sicnh = Navicula Sicnla. — Smooth, and broadly navi- 
cular laterally ; the margin with longitudinal lines ; ends subacute- 
Length l-528th. 

^v-RiuEhTakAmphiboia. — Striated, and mdely linear; on the lateral 
surface cuneate, subacute at the extremities ; on the dorsal aspect, 
ends obtuse ; pinnules fifteen in 1-1 200th. Length 1 -324th. Has 
the general form of S. Regula. Kurdistan. 

Ehrenbcrg remarks, that he is not sure to what genus this belongs ; 
he has sometimes thought a slender umbilicus existed, as in Pinnu- 
laria ; but its fonn is singular, in presenting equal transverse striae 
on each side. 

S. Irevis. — Short, striated ; has the figm^e and size of S. striatula, 
but its strise are larger and more slender; sixteen in l-1200th. 
Length 1-9 12th. Kurdistan. 

S. Lepida. — Slender,linear lanceolate, one end extremely obtuse, the 
other more tapering and subacute ; striae nine to ten in 1-1 152nd ; a 
distinct curved line extends along the centre on each lateral aspect. 
Length 1-76 8th. Kurdistan. 

S. (?) elli2}tica. — Elliptic-oblong; a slight longitudinal line extends 
down its centre, and it has parallel transverse striae. Length 
1 -480th. In form approaches the genus Rliaphonek. 

S. cremdata. — Ovate lanceolate, margin crcnulate ; ends somewhat 
unequal, subacute ; eleven crenules in 1-1 152nd, extending into pin- 
nules. It has also a distinct median suture. Diam. l-1080th. Fossil. 

S. IcBvigata. — Lmceolate, elongate, smooth, ends obtuse, somewhat 
unequal ; a distinct median suture exists, with two longitudinal 
lateral lines. Length l-168th. 

S. leptoptera. — Lanceolate, ends acute, rather unequal ; pinnules 
dense, six in 1-1 152nd; median suture dilated, distinct. A specimen, 
1 -456th long, presented twenty-one pinnules. Fossil, Oregon. 

S. Oregonica. — Spathulate in figure, ends subacute, unequal ; 
median suture broad and distinct ; pinnules strong ; about the middle, 
from four to five in 1-1 152nd, Length l-336th, and in this nineteen 
pinnules were met with. Fossil. 

S. reflexa. — Lanceolate, extremities unequal, subacute, slightly 
reflexed ; central suture distinct ; pinnules strong, about centre three 
to four in 1-1 152nd. Length 1-1 80th. Fossil in Oregon, 



Navicidacea.'] infusohial ANiMAtcuLES. 407 

SuniKEi.LA (?) Jinea. — Eacillar, largo ; one side cuneate, the otliev 
rounded, minutely and transversely striated throughout. Length 
1 -240th, 

S. stijlus. — Large, styliform, and narrow, quadrangular ; one end 
more obtuse than the other, but neither acute ; pinnules fifty-four in 
l-144th. Length l-144th. 

S. CaJedonica. — A species discovered by Elii'enberg, in earth sent 
from Ireland. 

S. plicata. — From the same source. 

S. a!<pera. — Large, with loosely disposed pinnte, which also present 
rough crests, four to five in 1-11 5 2nd. Ehrenbcrg says, "I have 
seen but a fragment, if a Campyhdisms ? " From volcanic earth, 
Hochsimmer, on the Rhine. 

S. spiralis (Kiitz.) — Primary side linear, spirally twisted, with a 
dotted margin; dots five to six in l-1200th. Length l-300th. 
Nordhausen. 

S. didyma. — Oblong, truncate at each end, sinuate, constricted at 
the middle; margin punctate. Length 1- 600th, 

S. solea = Surirelh Lihrih (Ehr.) 

S. multifasciata. — Narrowly linear laterally ; dorsally cuneate, acute 
at each end; transverse striae very fine, obsolete. Length 1 -288th. 

S. thermalis = Pinnularia (?) thermalis (Ehr.) 

S. amhigua (Kiitz.) — Broadly oblong, trmicate at each end; trans- 
verse striae rather wide, straight, obsolete, four in l-1200th. 
Length 1 -264th. Bernese, Obcrland. 

S. ohlonga. — One end attenuate, broadly obtuse, and rounded, 
Binuoso-dentate near the margin. Marine. 

S. elliptica (Kiitz.) = S. oophcena (Ehr.) see Cijmatopleura elliptica. 

S. Fatella. — Elongated, elliptic, equally rounded at each end ; 
marginal striae four to five in 1 -1200th. Length 1 -300th. Fossil. 

S. augusta. — Minute, linear-oblong on sides, rectangular dorsally, 
equally rounded at both ends, with the margin finely striated ; striae 
eleven in 1 -1200th. Length 1 -600th. Alive in ponds, No rdhausen, 

S. ovalis. — Oblong and cimeate ; laterally ends truncate ; dorsally 
ovate-elliptic, the one end more narrowly rounded than the other ; 
marginal striae eight in 1 -1200th. Length 1 -360th to 1 -280th. Costal 
only visible at margin of valves. Freshwater. 



408 DESCRIPTION OF \^Polygasirica, 

SuETKELLA ovttta. — Small, laterally -widely cuneate and truncate ; 
dorsally ovate, with delicate marginal striae, seven to nine in 
l-1200tli. 

Var. (h.) dorsally equally elliptic. Length 1-I200thto l-560th. 
Common in ponds. 

S. (?) ornata. — Elongate, truncate at each end, with obtuse angles ; 
longitudinally cleft, and ornamented with minute puncta, disposed 
in decussating lines. Length l-280th. Breadth l-960th. Among 
Algae, Genoa. Kiitzing has seen this form but once. 

S. (?) Adriatica = Podocystis Adn'atica. Small, supported on a 
short stipes, cuneate laterally ; dorsally obvate ; striae transverse, 
eleven to twelve in l-1200th. On Callithamnion, at Trieste. 
Length 1 -620th. 

S. minuta, (Smith.) — Frustule on front view (laterally Ehr.) wedge- 
shaped ; on side view (dorsally, Ehr. ) elliptical or slightly ovate, 
with ends more or less rounded ; costae marginal. Average length 
l-1200th. Greatest breadth l-2500th. In streams. 

S. salina (Smith.) — Erustule on front view wedge-shaped; on side 
view ovate ; the larger end rounded, and the smaller more or less 
pointed; costae marginal. Average length 1-6 00 th; greatest breadth 
1-1 200th. In salt-water ditches, Poole Bay. 

" This nearly resembles S. mimita, but is a salt-water species, 
usually larger and distinctly ovate, and with the smaller extremity 
of the valve, in most of the frustules, somewhat attenuated. On 
the other hand, it is much smaller than S. oralis (Kiitz.) less oblong 
and stout, and of marine habitat. 

S. circumsuta (Bailey.) — Outline nearly elliptical, with a scarcely 
perceptible constriction at the middle ; surface with very minute 
granulations, and a faint longitudinal line through the middle ; 
edges with a continuous row of nearly obsolete pinnulae. Hudson 
Eiver, west points of Florida. 

Sub-genus I^avictjla — True Navicula. — Lorica smooth, or with lon- 
gitudinal lines or stripes ; central aperture round. This last circum- 
stance distinguishes it from Stauroneis, whilst its general symmetry 
separates it from the smooth forms of Cocconeis, which has one 
surface depressed or flattened. 



Navlculacea.l infusorial animalcules. 409 

Navicula gracilis. — Smooth, slender, lanceolate; ends acute 
laterally, linear, truncate. Common ; freshwater and fossil. Length 
l-1500th to l-o60th. 

N. (?) pellucida = AmiMplmra pcUiicida (Kiitz.) — Slender, lan- 
ceolate, smooth (no median aperture, Kiitz.), see fig. 140, which 
rei^resents a group, and a transverse section, to show the position of 
the central furrow on each side. Found -ndth the preceding. Length 
1 -300th to 1 -140th. It has the general form of a Closterium ; and 
the apparent absence of an umbilicus, would certainly determine its 
position with some other genus than Navicula. 

N. mm (1838) r= Ceratoneis acus (Ehr.) and Synedra sultilis (Kiitz.) 

N. umhonata. — Smooth, sti'aight, constricted near the middle, 
causing the ends to appear larger, hence its name. Length 1 -430th 
to 1 -240th. Salt and fresh water, and fossil. Kiitzing adduces 
this as his Surirella thermalis, and the Pinnularia (?) thermalis of 
Elirenberg ; and, as is thus implied, furnished with transverse striae, 
delicate though they are. If such striae exist in any degree, this 
species should certainly be excluded from the present sub-genus. 

K. fulva. — Smooth, broadly lanceolate ; slightly produced at the 
ends in the form of a beak or rostrum (^. e. ends rostrate), colour 
yellowish-brown; umbilicus -very small, round; lateral aspect 
narrowly linear and truncate. Length 1-1 150th to 1-1 80th (P. 15, 
f. 5.) Alive and fossil. 

IT. amphish^na. — Smooth, broadly elliptic (see group 141), apices 
much contracted ; umbilicus circular ; granular contents of golden- 
yellow colour. Ehrenberg remarks, that the vibratile process, seen 
by Bory St. Yincent, was, in fact, the locomotive organ, the action of 
which is readily seen, though the process protrudes but a very little 
beyond the lorica. Length 1-1 700th to 1 -240th. Ercsh water. 

N. nodosa. — Smooth, linear, -ndth three undulations on each side, 
about the middle ; extremities contracted, shortly rostrate and obtuse 
(see fig. 143.) Central opening round. Length 1 -430th. 

X. Cari. — Slender, lanceolate, smooth ; ends acute ; umbilicus 
circular. Length 1-1 150th. Fossil at Cassel. 

N. Baltica. — Large, smooth ; sigmoid, by the curvatui'e of the 
attenuated obtuse ends in opposite directions (fig, 144.) Central 

£ £ 



410 DESCRIPTION o¥ [Pol^ffasfrica. 

opening small, round. Length l-70th. Found in phosphorescent 
sea-water. 

Nayicula hippocampus. — Smooth, sigmoid, lanceolate; apices obtuse ; 
laterally linear and truncate (gi'oup 145.) Sometimes it has deli- 
cate longitudinal striae. Length l-90th to l-70th. In fresh and 
salt water. This shell is the well-known test for microscopes. See 
descriptions of Plates 19 and 20. 

N. Sipna = N. acuminata (Kiitz.) — Smooth, lanceolate, sigmoid, 
ends attenuate, obtuse; laterally straight (group 146.) It often 
contains motile granules, and has a golden-yellow colour. Length 
1-2 10th to 1-1 40th. In fresh and salt water. 

N. scalprum. — Smaller, slightly sigmoid ; apices gradually taper- 
ing, obtuse, with longitudinal lines. Length 1 -430th to 1 -290th. 

N. curviila. — Narrow, linear lanceolate, sigmoid, apices rather 
obtuse ; no longitudinal striae. Lateral view straight. Fresh water. 

N. Trochus. — Short, smooth, enlarged at the centre, constricted 
near the ends, which are much produced and truncate. The surface 
is marked by several longitudinal stripes. Length 1 -860th. Fossil 
in Sweden. 

N. AgeUus. — Large, of a sigmoid lanceolate figure on the back, 
with very fine longitudinal lines, and having a furrowed space ; 
straight and nearly linear on the side, with subacute extremities. 
Length l-180th It is more slender and longer than N. Hippo- 
eampus. In fresh water. Common. 

N. linodis. — Probably but the young of N. hihrile. Fossil at San 
Fiore, Italy == Fragilaria linodis (Ehr.) 1843. 

N. carinata. — Lanceolate, linear laterally, and with a broad longi- 
tudinal dorsal keel. Length 1-2 16th. Fossil on shores of the 
Rhine in volcanic schists. 

N. eurysoma. — Small, ovate; ends obtuse; quite smooth; margin 
distinct. Found in African chalk-marl. Not improbably a Cocconeis. 

N. inversa. — Short, dorsally narrow and sigmoid, "with subacute 
ends ; laterally quadrangular, very broad, constricted at the centre, 
with the ends widely truncate, and marginal glands (?) It moves 
quickly; is allied to N. alata, but wants the winged portions. 
Length 1-5 76th. 



Kavictdacea.'] iNFFSoniAt animalcules. 411 

Navicula rostrata. — Large, very broadly lanceolate, almost rliom- 
boid ; extremities acute, rostrate. Centi'al aperture large, lateral view 
linear, truncate. Length 1-2 16th. Fossil. 

N. affinis. — Linear dorsally, constricted at each end, which is 
shortly rostrate and obtuse. Approaches Plmiularia dicephala. Length 
l-570th to l-420th (P. 15, f. 32.) 

N. amhigua, — Linear-oblong dorsally, sub ven trie ose, contracted at 
each end, which is produced but obtuse. Resembles very closely 
the former species. 

N. (?) Americana. — Oblong and turgid dorsally, slightly constricted 
in the middle ; ends widely rounded. 

N. (?) amfliigomphus. — Larger, oblong ; sides smooth ; ends wedge- 
shaped, with or without faint longitudinal lines. 

N. amphioxys. — Dorsally narrow, linear lanceolate, without longi- 
tudinal lines or striae, attenuated at the ends, subacute. More 
elegant in figure than N. gracilis. 

N. amphirhynchus. — Dorsally elongated, lanceolate, suddenly con- 
sti'ictcd towards the ends, which are produced and truncate (P. 15, 
f. 6.) Has a wider foi'm than N. amphishcena. 

N. amphisphcma. — Dorsally acutely lanceolate, gradually attenu- 
ated towards the ends ; umbilicus oblong, in which it differs from 
N. fulva, which has a round umbilicus. 

N". Bacilhon. — Smooth, linear dorsally and bacillar ; ends rounded. 

N. biceps. — Smaller than preceding, dorsally broadly lanceolate ; 
apices rather constricted, but obtuse. Mexico and North America. 

N. carassius. — Small, widely lanceolate on back ; ends suddenly 
constricted, obtuse, but rather prolonged. Shorter and wider than 
N. amphinbana. Surinam. 

N. dilatata. — Large, dorsally elliptic-lanceolate, laterally rather 
convex, with longitudinal lines ; ends obtuse. 

N. JDirhynchis. — Small, dorsally narrowly lanceolate ; ends elon- 
gated, rostrate, obtuse. Mexico, Labrador. 

N. dubia. — Small, linear lanceolate on back ; sides rather cui'ved, 
the curve extending to the subacute prolonged ends. Surinam. 

IS. duplicata. — Oblong, small ; constricted at the middle (panduri- 
form) ; ends attenuate. A^])roaches Pinnularia didyma. Cuba. 

E E 2 



412 DESCRIPTION OF \Toly(jasiripa. 

Navicula Formica. — Oblong, linear dorsally ; constricted in four 
places ; segments oblong. Marine in United States. 

N. Fusidiuvi.' — Large, nairowly lanceolate on back, slightly con- 
stricted at the ends, which are rounded and capitate. 

N. mtchcockii. — Dorsally broadly linear, oblong; laterally con- 
stricted in two places, thus producing throe equal projections ; ends 
suddenly cuneate, subacute. Massachusetts. 

N. Iridis. — Large, elongated, bacillar ; sides plane ; apices slightly 
attenuated, obtuse ; surface very finely striated longitudinally, causing 
it to display various colours. If sui generis (?) New York. 

N. leptogongyJa. — Smooth, small, linear, slender; a central round 
protuberance on the back ; ends obtuse, rounded, rather dilated. 
Thun and Labrador 

N. leptorhyiichus.—^vaH)! ; dorsally, linear lanceolate ; ends very 
long, rostrate, straight, subacute. Approaches N. dirhjncus, but 
ends longer rostrate. Mexico. 

!N . limbata. — Small, linear dorsally ; sides sti'aight ; internally, as 
if widely bordered (limbate) ; apices suddenly constricted, but trun- 
cate. Chili. 

N. Uneolata. — Small ; on dorsum narrowly lanceolate, with longi- 
tudinal fine lines ; ends acute ; on side widely linear. Length 
1 -288th. Freshwater. 

N. Lyra. — Larger, broadly elliptic-lanceolate ; ends constricted, 
obtuse ; surface with a central double raised band, in the form of a 
lyre of two cords. Falkland Islands. 

K. nn,esolepia. — Linear, elongate, undulate on back, slender ; 
three undulations at the centre ; ends much constricted, rostrate, 
obtuse. Length 1 -420th. 

N. mesotyla. — Smooth, narrowly linear laterally, slender on the 
back, with a central spherical enlargement ; apices contracted, 
obtuse. Length 1 -420th 

'^.ollonga. — Oblong-lanceolate and subacute, not produced (rostrate) 
Salt water. Length 1 -720th. Mexico. 

N. oltma. — Small; oblong dorsally, and lanceolate; ends rounded, 
obtuse. Kiitzing thinks it probably identical with N. afpendiculafa. 
North Anicrica. 



Naviculacea.'] infusoiual animalcules. 413 

Navicula {^) jniradoxa. — Large, quite smooth, widely obloug- ou 
back ; slightly constricted at the middle ; ends cuneate, obtuse ; 
centre longitudinally dotted. Pern. 

N. Ehomhea. — "VVidoly lanceolate on back, almost rhomboidal, -^dth 
delicate longitudinal lines; ends acute. Length 1 -480th to 1 -360th. 
Mexico. 

N. Semen. — Back ovate, turgid, ventricose at the centre, obtusely 
rounded at the ends. Variety (</.) Ends rather constricted — N. 
Chilensis. Var. {h.) Ends rounded — IS". Lahrador. 

JST. Silicula. — Smooth, linear, elongate, with three equal protube- 
rances (nodes) on back ; one at the centre, and one at either end, 
hence the ends obtuse. North America. 

N. Sphocrophora. — Lanceolate, ends produced (rostrate), capitate 
and papillate. Length 1 -320th. In fresh water. 

N. Trabecula. — Linear, elongate, ^ith a single node at the centre, 
ends not contracted, and round. Kiitziug thinks it to be a variety 
of Pinnularia decurrens. 

N. nodosa. — Small, broadly oblong on back, sides with three equal 
swellings; ends constricted, obtuse. Approaches N. Ilitchcockii. North 
America. 

N. (?) omphalia. — Large, with gi-anulai- lines, which, from being 
very finely decussated, reflect various colours ; umbilicus solid, 
round, clear, with the median suture passing through it. A Iju-ge 
and elegant species. Fragments from Bermuda, l-192nd in size. 

N. elliptioa. — Elliptic; ends imperfectly subacute; central uni- 
biliary, subquadi-ate ; three fine sutures ; margin wide, very minutely 
dotted. Length 1-5 76th. Southern Ocean. 

N. Cantonensis. — Broadly ovate, lanceolate, very smooth ; ends 
acute, little produced. By its shorter acute ends it differs fi-om 
l^.fuka. Length l-480th. Canton, China. 

N. Sinensis. — Flexuose, sigmoid, larger than preceding, very 
smooth; ends widely rounded, expanded in the centre. Length 
1-1 80th. 

N. tortuosa. — Bacillar, smooth, rather turgid, and tortuose. Length 
1 -288th. 

N. decussata. — Oblong-eUiptic, strong, constricted at each end, as if 
obtusely mucronate ; surface elegantly sculptured by decussatiu" 



414 DESCElPTiON OF [Poli/ffastrica- 

dotted lines ; tlie puncta aiTanged in a quincunx. Has the habit at 
of N. amphishana. 

NayicTjLA lej^tosfi/Ius. This fossil species, and the seven following, 
were discovered by Ehrenberg in earth from Ireland. 

N. Cocconeis. 

N. AmpMrrina. 

N. osmlata. 

N. hirostrts. Probably Stauroneis hirostris. 

IS. Sti/lus. 

IS. amphiata. 

N. mesopachya. 

N. diaphana. — Large, elongate, lanceolate ; apices obtuse ; surface 
very smooth, diaphanous ; umbilicus not perforating ; a double lon- 
gitudinal line down the centre. Habit of Stauroneis Phcenicenteron. 
(l-192nd.) 

N. I)emerar<2. — Smaller ; oblong and smooth ; venti-ally, rhomboid, 
and tumid; apices acute, attenuate, and subrostrate. Length 1-576'Lh. 

!N. Schomburglcorum. — Large, elongate, lanceolate, with obtuse ex- 
tremities, and the habit of N. diaphana, but with three longitudinal 
lines (sulci) on each side the umbilicus. Length 1-1 80th. Alive in 
Guiana. 

Nageli describes (Report Ray Society, 1846, p. 221,) what he 
assumes to be a new species of Navicula, nearly allied to JVavictda 
striata (Ehr.) = Surirella Striatula (?). He found it in brooks 
about Zui'ich ; it exhibits no movement. The contained matter is 
brown, and fills the whole of the central cavity, except the horns 
(prolonged extremities), which are ti^ansparcnt and uncoloured. 

Nageli adduces this species as illustrating the existence of a 
nucleus and nucleolus in the interior ; and it is in it also that he 
" observed a pretty rapid circulation of the granular contents, the 
gi'anules passing from the nucleus outwards, along the edges, and 
back again to the former." 

Kiitzing divides his genus Kavictda into six sections ; it includes 
numerous species of the genus Pinnulm'ia, as that natui-alist does not 
recognize the presence or absence of transverse striae as a generic 
distinction. In his recent volume, " Species Algarum," he enume- 
rates 179 species, including nine doubtful; most of them are de- 



Naviculacea.] infosohial animalcules. 415 

scribed liereiu uudcr oue or othor of the sub-geuera. The sections 
herein remain the same, viz. — 

a. — Form lanceolate, eighty species. 

b. — Eorm oblong or elliptic, twenty-nine species. 

c. — Form gibbous, sixteen species. 

d. — Form constricted or nodose, thirty species. 

e. — Form lunate, t"\;\ro species. 

/. — Form sigmoid, thirteen species. 

Sub-genus Pinnulaeia. — Umbilicus round ; surface transversely 
striated. 

P. viridis. — Lorica transversely striated; straight, lanceolate, oblong; 
obtuse and truncate at the ends ; striae fifteen in 1-1 200th. Common, 
living and fossil. Figs. 133 and 134 represent living, and figs. 135 
and 136 fossil forms. (P. 15, f. 15 and 31) ; the arrows in the two 
first figures indicating the direction of the current produced. Length 
1-1 150th to l-70th. In the interior, numerous changeable vesicles 
are seen, connected together by means of an irritable gelatinous 
matter, which is as clear as crystal, and from whose motion these 
globules often appear to tremble. Ehrenberg has noticed moveable 
dark spots near the extremity of some specimens, similar to what is 
seen in Chsterium, &.c. The progress of longitudinal self-division 
may often be observed beneath the siliceous lorica. The six openings 
of the lorica are easily seen, tlu'ee being upon the upper sui'face and 
three on the lower. The lorica near the central opening being 
depressed, the aperture appears eccentric, in respect to the medial 
line. Found at Hampstead, and fossil in Bohemia, Sweden, &c. 

P. mequalis. — Striated and unequally convex (see group 154.) ; of a 
yellowish colour. In 1-lOOth of a line are ten or eleven striae. 
This species forms the passage to the genus Eunotia. Found living, 
at Tilbury Fort and elsewhere ; also fossil at San Fiore. Length 
1 -430th to l-120th. The unequal sides in this species would render 
it, in Kutzing's classification, a member of the genus Cymhella. 

P. macihnta. — Slender, elongated, attenuated towards the obtuse 
rounded extremities; striag twenty-three in 1 -1200th; strong, 
oblique, and converging to the centre. Fresh water and fossil. 
Length 1- 140th. 



416 DESCRIPTION OF {^Pohjrjastrica 

PrtfKTTLAKiA cttfUata. — Short, ovate, lanceolate, ventricose at the 
centre; ends constricted and obtuse ; strife ten in 1 -1200th. Length 
Ml 50th to l-576th. 

p. dicspTxala. — Linear, elongate, constricted, and obtuse at each 
end, which consequently appears capitate; striae nineteen in 1 -1200th. 
Length l-860th to l-480th. Fossil in North and South America, 
and Sweden. 

P. /«?iceo?a^«5.— Lanceolate, elongate, tapering from the turgid centre 
to the acute extremities ; both longitudinal and transverse stripes, 
thirteen of the latter in l-1200th. Length 1-1 150th to l-280th. 

P. viridida. — Straight, lanceolate, slender, one end truncate, the 
other attenuate and obtuse; strise thii'teen to fifteen in 1-1 200th. 
Length 1 3000th to l-280th. Alive and fossil. 

P. did/yma. — Striated, rather broad ; viewed from the side, linear ; 
truncated at both ends, and entire; viewed dorsally, constricted in 
the middle ; ends sub-orbicular ; it thus ajipears as if formed of two 
discs joined together. Twenty-three strice in 1-1 200th. Fossil in 
the chalk marl of Caltanisetta, living in sea water. This species 
was first observed alive, afterwards fossil, in Sicily. Similar forms 
are very numerous in the chalk marl of Greece. It is distinguished 
from P. entomon by the want of the constriction when viewed on the 
lateral surface; ventral surface with a central colourless stripe. 
Length 1-1 150th to 1 -480th. (P. 24, f. 12.) 

P. iVbri^^^?cfi?.— Laterally linear, narrow, and truncated at both ends , 
dorsally broadly ovate, and acute at the extremities ; circumference 
with a narrowly striated margin, area smooth; thirty strife in 1 -1200th. 
The N. praetexta, of the Greek chalk marl, is very similar to this 
species. Length 1 -360th. 

P. quad/rifasciata. — Laterally narrow, linear, truncate; dorsally- 
broadly ovate, ends acute, margin wide ; a double longitudinal narrow 
striated band on each half ; hence it is apparently marked by four 
stripes or bauds, whence the name. Striae twenty in 1- 1200th. 
Alive in the Baltic. Fossil in the chalk marl of Greece. In the living 
state it is of a greenish or rusty yellow colour. Length 1 -430th. 

P. cequalis. — Large, lanceolate, oblong, ends constricted, obtuse ; 
Bides even, miiuilcly piuuate. Iceland. 



Navicnlacea.'] infusorial animalcules. 417 

PiNNULARiA amphijomphits. — Largci-, oblong dorsally, sidi's 
plane, ends acutely wedge-shape ; it is remarkable by indistinct 
longitudiual lines ; approacbes Navicida amj)hi(/omj?hus. 

P. amj)luoxys. — Narrow, linear lanceolate, acute; sides with 
straight pinnules. New York and Iceland. 

P. amphiprora. — Larger on back, narrowly lanceolate, ends broad, 
obtuse ; it has the habit of Ainphiprora Navicida, but with marginal 
apertures at the extremities. Massachusetts. 

p. Apis. — Oblong on the back, and so much constiicted at the cen- 
tre, as to be nearly cUvided into two sub-oi'bicular segments ; ends 
obtuse, pinnules rough (granules), and twelve in l-1200th. Vera 
Cruz. 

P. horealis. — Striated, small, laterally linear, ends rounded, but 
not constricted; pinnules strong. Has the habit of Fragilaria 
pinnata. ChiH, New York. 

P. chilensis. — Larger, oblong, straight to the sides ; ends broadly 
rounded, not constricted ; pinnules strong, and eleven to twelve in 
1- 1200th; approaches P. wr/i/s, but is shorter and broader. Chili. 
(P. 15, f. 33.) 

P. (?) Conops. — Oblong on back; divided into two cordate 
parts by a central constriction ; ends apiculate ; pinnules very 
minute. Vera Cruz. 

P. costata. — Large, thick, short, ovate, oblong; ends Avidely 
rounded; pinnules large, prominently costate, six in l-1200th; 
approaches P. Dacfi/Ius. North America. 

P. Cyprianus. — Oblong-lanceolate, ends widely rounded, umbilicus 
oblong. Chili. 

P. Dacti/lus. — Long, bacillar, straight laterally ; dorsally very slightly 
curved toAvards the extremities, which are broadly rounded ; pinnules 
fourteen in 1-1 200th. North America. 

P. decurrem. — Stiiated, narrow, elongate, lanceolate ; dorsally 
broad, and tiimid at centre^ somewhat narrowing towards the extre- 
mities, which are however widely roimded ; approaches P. gibba and 
= P. Trabecula, a smaller variety. 

P. dwiiiphala. — Short, broadly lanceolate on back, ends constricted, 



418 DEScEiPTioN OF [PoIj/ffasMca. 

obtusely truncate ; central umbilicus transverse, and divided by a 
longitudinal line into two parts. Mexico. 

PrNNULARiA disphenia. — Striated, linear, elongated dorsally, sides 
straight ; ends acutely wedge-shaped ; pinnules of margin veiy 
minute ; ai^proaches P. ampMgomphus. 

P. Entomon. — Larger, elongate, widely constricted at centre, 
(panduriform) presenting two oblong portions with cuncate ex- 
tremities, subacute ; striae smooth, not granular ; broad, nineteen to 
twenty in 1-1 200th. Alive and fossil. 

P. Esox. — Large, elongate ; naiTowly lanceolate, dorsally, slightly 
undulate on the sides ; three undulations on each side, of which the 
central one is the most marked. Extremities very attenuate, but 
obtuse. (P. 15, f. 43.) ChiH. 

P. Gastrum. — Striated, small ; underside widely lanceolate ; ends 
constricted, but little produced, and obtuse, with granular eminences. 
Mexico. 

P. Gigas. — Very large, wand-shaped, slightly gibbous at centre of 
dorsum, gently diminishing towards extremities, which are rounded ; 
nine pinnules (striae) in 1-1 200th; approaches Y.nohilis. North 
America 

P. heteropleura. — Broadly lanceolate on the back ; sides unequal ; 
ends slightly constricted and broadly obtuse. Is near P. inmqualis, 
the ends of which are however sub-acute. 

P. isocephala. — Linear on back, undulate, with five eminences 
(nodules) produced by as many constrictions, somewhat of unequal 
size ; whence it has a moniliform outline. Scarcely differs from P. 
Monile which is larger. 

P. macilenta, — EaciUar dorsally ; sides straight ; ends rounded, 
wide ; pinnules nan-ower and closer than in preceding, there being 
eighteen to twenty in 1-1 200th. This species = P. pohjptera, which 
is probably but a more slender variety. 

P. mcesogongyla. — Striated, styliform, and bacillar ; gibbous at the 
middle dorsally ; ends rounded, wide, not turgid ; near P. nohilis. 

p. monile. — Very small ; striated dorsally, constricted so as to form 
five equal siib-globose segments ; viewed on the sides, it is linear 
and truncate. Approaches Navicula nodom, Length l-864th. 



Naviculacea.} infusokial animalcules. 419 

PiNNTiLARiA 7iobilis. — Yd'y large, striated, of an elongated, quad- 
rangular, bacillai- figure ; turgid at the centre, and slightly so at the 
extremities. Length l-84th. Pinnules sixteen to eighteen in 
l-l'iOOth. Fossil in South America. Terminal apertures very large. 
San Fiore, Cayenne, Brazil. 

P. pachyptera. — Striated, large, oblong, bacillar, but short and 
thick ; gibbous in centre of dorsum broadly rounded, not const:"icted 
at extremities. Pinnules very strong, six in l-1200th. Labrador. 

P. peregrina. — Striated, linear lanceolate, narrow, ends gradually 
tapering, acute, not constiicted ; pinnules oblique. St. Domingo, 
Cuba, New York. 

P. pisciculiis. — Striated, very delicate ; narrowly linear ; ends con- 
Btricted, prolonged, rostrate, and sub-capitate. Approaches P. di- 
eepJiala. Cayenne. 

P. place?itula. — Small, very broadly lanceolate, oblong, ends con- 
stricted, obtuse, rather produced, papillary ; near P. gastrum, but 
larger. Vera Cruz, Mexico. 

p. porreda. — Striated, larger ; lanceolate, elongate dorsally, widely 
expanded at the centre ; ends gradually attenuate, but broadly ol)tuse ; 
pinnules oblique. Is near to P. decurrens. Central and North 
America. 

P. praetexia. — Large, elliptic ; margins on the dorsal aspect ex- 
panded, furnished with very broad pinnules, whilst the inter- 
mediate space (median area) is gTanuliu- j striae seventeen in 
l-1200th. Length 1 -288th. Fossil in Greek marl. 

P. Sillimanorum. — Striated ; large, lanceolate dorsally ; widely 
expanded at middle or ventral surface, oblong; ends constricted, 
produced, obtuse, and sub-capitate. Approaches Biomphalus Clame 
Herculis. New York. 

P. sinuosa. — Small, narrow, linear lanceolate, sigmoid ; striae fifteen 
in l-1200th. Mouth of the Elbe. Has the figure of Navicula 
sigma, but is more slender. 

p. Tahellaria. — Bacillar, slender, of thi'ee segments (Trinodal) being 
turgid at centre, and having capitate extremities. Is more slender 
than P. nohilis, which it about equals in length. Central and North 
America. (P. 15, f. 2L) 



420 DESCRIPTION OF {Tolygastrica. 

PiNNiJLARiA Termes. — Striated, small, narrow, oblong, rather con- 
stricted at the ceuti'e, and towards each end ; the ends obtuse, widely- 
rounded, and produced. 

P. Utriculus. — Striated, oblong dorsally, sides straight, slightly 
curving towards the ends, which are tapering but obtuse. Approacjhes 
P. (lisplwnia. Mexico. 

P. caraccana.—k. variety of P. horealis, larger and more dilated at 
the middle. Length 1 -480th. 

P. oceanica. — Elliptic- oblong ; its length twice its breadth, ends 
subacute ; umbilicus small, round, clearly defined ; suture double, 
margin very delicately but widely pinnate ; pinnules twenty in 
1-1 200th. Length 1-5 70th. Southern Ocean. 

P. lamfrocampa Very large, sigmoid, slender, lanceolate ; very 

delicate striae on margin; apices subacute. Length l-144th. 
Pinnules are visible in the dry state, but not in the living. It is 
very mobile. Baltic and Falaise. 

P. lihyca. — Striated, small ; dorsally navicular, ovate-lanceolate, 
acute ; laterally quadrangular and truncate ; pinnules fourteen in 
1-1 200th. Habit of Kavicula fulva, but is wider and not rostrate. 
Length l-5a0th. Oasis, Sinai. 

V. Kefvingensis. — Striated, small, _ lanceolate, and navicular dor- 
sally ; pinnules converging towards the centre, and seventeen in 
1 -1200th. Length 1 -430th. ; very close to P. viridula, but more 
slender. 

P. (?) thermalis. — Small linear ; cuneate and acute dorsally ; laterally 
truncate. Length l-576th. In warm springs. Habit of Fragihria 
acuta; umbilicus unknown. 

P. Furcida. — Small, dorsally elliptic ; oblong on both sides, 
linear ; apices constricted, umbonate (bossed) ; pinnules converging 
to the centre. Length l-864th. to l-720th. Lossil. 

P. Gemina. — Small, divided by a constriction, existing on each 
aspect, into two lenticular segments ; remarkable by a central spine ; 
(a/piculus) when seen on the side. Length l-840th. to 1 -648th. 

P. Semimdum. — Found by Ehrenberg in the plastic marl of 
^gina. 

P. coardata. — The same habitat. 



Navicularea.] infusorial animai-cfles. 421 

PiNNXTL^uaA contract a. — The same habitat. 

P. tceniata. — Small, on dorsal aspect, umbilicus distinct ; pinnules, 
marginal, strong, ends suddenly constricted, prolonged, rounded, and 
obtuse. (P. 24, f. 15.) 

P. Australis, P. pleuronectes, and P. styliformis, new species dis- 
covered by Ehrenberg in earth from New Holland. 

P. ampJmtijlus. — Bacillar, elongate, turgid at the middle ; apices 
attenuate, filiform, obtuse ; pinnules fine. Length 1 -372nd. Fossil 
in Oregon. 

P. leptostigma.-^O'hlong-ldincQolaie, length twice its breadth; 
apices subacute, rather produced ; very fine transverse dotted lines, 
(pinnules) inconspicuous. Length 1 -432nd. Fossil. 

P. Oregonica. — Elongate, navicular, bacillar, uniformly and 
gradually decreasing towards the rounded apices ; pinnules strong, 
twenty -three in l-1152nd. Length l-228th. Fossil in Oregon. 
It approfvches P. Digitum, but is more slender. 

P. Sckomhurgliii. —Itarge, lanceolate, equal, length thrice its 
breadth; apices subacute; pinnules twenty-five in 1 -1152nd. ; ap- 
proaches P. cequalis, but is smaller and more obtuse. Length l-264th. 
Guana. AUve. 

P. Couperii (Bailey.) — Large, slightly constricted in the middle, 
with two marginal and two intermediate punctato-striate bands, the 
latter interrupted at the centre. The outline is like that of P. para- 
doxa (Ehr.), and the markings somewhat resemble those of P. lyra. 
Southern States of America. 

P. permagna (Bailey.)— Large, lanceolate on the ventral surfaces, 
with punctato-striate marginal bands ; and a broad, smooth, central 
stripe ; ends slightly rounded. Abundant in the Hudson Eiver, at 
"West Point, New York. 

P. eequinocfiaUs (Montague.) — Rather large, linear-oblong, apices 
rounded, pinnules radiant, strong, four in 1 -2600th. Length of 
fiaistule 1 -260th. to 1-1 50th. Found with Algte in British Guiana. 
It, in general fonn, resembles P. Dactylus, but differs in its size and 
larger striae. In the last particular it resembles P. pacliyptera, 
but that species has a median dilatation or gibbosity. Montao-ne, in 
his notice of the ciyptogamic plants of Guiana, (Ann. de. sc. Nat. vol. 



422 DKSCHiPTiON OF [Polygastrica, 

14, 1850, p. 308), has described this species as a Navictila, but 
the transverse striae determine it to be a Pinnularia in Ehren- 
berg's plan. 

Sub-genus Biploneis. — The three following species have been 
described by Ehrenberg under the name of Biphneiz, by which 
appellation it would seem he wishes to designate a sub-section of 
Pinmdaria, having some distinguishing peculiarity, which, however, 
has not been met with in his writings. 

From the figiu'e of Bifloneis Didyma, it may be presumed that 
Ehrenberg intends this sub-genus to include Pimiularia, constricted 
at the middle, in the dorsal and ventral aspect, and having, so to 
speak, a double {diplos Gr.) outline. 

D. JBombus. — Constricted, with sub-cordate segments ; apices sub- 
acute ; strise dense, granular, twenty-one in l-12001h. ; granules 
of the largest striae in fours. Length 1 -384th. FossO in the 
chalk marl of ^gina. 

D. crabro. — Constricted, with widely separated elongate lanceolate 
lobes, subacute or obtuse ; striae strong but smooth ; eleven to twelve 
in l-1200th. Length l-276th. In chalk marl from JEgina. 

D. Didtjma. = Pinnularia Didyma. (P. 24, f. 12.) 

Sub-genus Statjeoneis (Ehr.) — Lorica smooth, or longitudinally 
striped ; median aperture (umbilicus) transverse ; but no transverse 

striae. 

Under this name Kiitzing includes all Navicxdce with a transverse 
median aperture, whether striated transversely or not. 

S. Plioenicenteron f Cymlella, Agardh.)— Smooth, of an elongated 
lanceolate fonn, with rather obtuse tapering ends ; longitudinal 
striae rare. It is very motile. Ponds, Hampstead ; and fossil at San 
Fiore, in Tuscany. Length l-400th. to l-140th. (P. 3, f. 139, and 
p. 15, f. 17 and 18.) 

S. platystoma. — Smooth, linear lanceolate, apices produced, widely 
truncate ; central opening transverse, (fig. 142.) Length 1-1 100th. 
to l-240th. 

S. ampMlepta. — Narrowly lanceolate, ends constricted, sub-capitate, 
rounded. Chili. 

S. aneeps. — Smaller than preceding; naiTow, linear lanccolato 
ends constricted, sub-capitate, and truncate. Cayenne. 



Naviculacea.'] inffsoeial animalcttles, 423 

STAtJRONEis Bailey i. — Broadly lanceolate, tapering gradually to 
the ends, whicli are obtuse. Surface with very fine undulating 
longitudinal lines; approaches S. ptcroidea and S. Phoenicenteron. 
North America. 

S. hirostris. — Smaller, narrowly lanceolate, ends produced, ros- 
trate, subacute. Siu'inam, Mexico. 

S. (?) constricta. — Small ; oblong ; constricted at the centre, and at 
the ends, which are much produced and obtuse. Chili. 

S. dilatata Small, broadly oblong on ventral aspect; laterally 

straighter ; ends constricted, obtuse, broadly and briefly rostrate. 
Mexico, Chili. (P. 15, f. 16.) 

S. fenestra. — Elliptic-oblong, with obtuse cuneate extremities ; 
quite smooth at centre, but with marginal parallel lines. Cayenne. 

S. gracilis. — Slender ; lineai', lanceolate ; ends tapering, truncate. 
North and South America. 

S. linealis. — Narrowly linear, oblong, ends tapering, obtuse, pro- 
duced, and rostrate ; parallel lines on the margin. Length 1 -720th. 
Trinidad, Nordlaausen. 

S. lineolaia. — Lanceolate, with dotted longitudinal lines ; ends 
tapering, subacute. Cayenne. 

S. Liostauron. — Styliform, slightly turgid at centre, extremities 
but slightly tapering and rounded. Iceland. 

S. Monogramma. — Oblong, turgid at centre; ends constricted, 
enlarged, rounded, sub-capitate. Surinam. 

S. Pohjgramma. — Lanceolate, with dotted lines, decreasing towards 
the ends, which are rounded and obtuse; central umbilicus expanded 
transversely. Cuba. 

S. Phylhdes. — "Widely lanceolate or elliptic, smooth ; ends much 
contracted, ro.strate, subacute. (P. 15, f. 7, 8 and 9.) South 
America. 

S. (?) pteroidea. — Large ; broadly and acutely lanceolate, with 
very minute dotted transverse lines, as if pinnulate ; ends obtuse ; 
approaches S. Baileyi. If a Stauroptera. (?) North America. 

S. Staurophcena. — Lanceolate, smooth, slightly constricted at the 
extremities, which are subacute. The central transverse umbilical 
band not very distinct. Approaches S. Phoenicenteron. North 
America. 



424 DESCHiPTiow OF \^Polygastrica' 

Staitroneis Sigma. — Has the form and size of Kavicida Sigma, 
but ^vitll au apparent double central exj)anded umbilicus. Length 
1 -240th. Richmond, Virginia. 

S. augusfn. — Discovered by Ehrenberg, in earth from Siberia. 

S. Aflantica. — Small ; lanceolate dorsally, with obtuse aj^ices ; 
linear laterally. Approaches S. ainphileptus. Var. of S. amphileptus of 
Chili; more obtuse. Length 1-11 52nd. In pumice from the 
Island of Ascension. 

S. lanceolata, (Kiitz.) — Slender, lanceolate, with subacute apices, 
which are also rather produced and acuminate. Length 1-1 80th to 
l-160th. Falaise. 

S. exiJis. — Veiy small, elliptic-lanceolate ; shortly rosti'ate. 
Length 1 -2400th. In fr-esh-water, Trinidad. 

S. amphicephala. — Linear-oblong, apices produced, rostrate and 
capitate. Nordhausen. 

S. injlata. — Oblong, widely expanded at the centre, and the two 
ends thus having two constrictions j ends widely rounded, truncate. 
Length l-480th to l-428th. Trinidad. 

S. ventricosa. — Very small, especially in the middle, and inflated ; 
capitate twice constricted ; umbilicus transverse. Length 1-1 320th. 
Nordhausen. 

S. pumila. — Elliptic-lanceolate, acute, margin punctate, striate ; 
laterally oblong, widely truncate. Length l-1440th to 1 -1080th. 
Christiana. 

Kiitzing does not make a generic distinction between Stauroneis 
and Stauropiera ; hence the present, and the following species, derived 
from his great work, are, as understood by Ehrenberg, Stauroptera. 

S. Aehnanthes = Stauroptera Achnanthes (Ehr.) 

S. aspera = Stauroptera aspera (Ehr.) 

S. Isostauron = Stauroptera isostauron (Ehr.) 

^.parva = Stauroptera parva (Ehr.) 

S, scalaris = Stauroptera scalaris (Ehr.) 

8. punctata. — Small, broadly lanceolate, apices produced, rostrate j 
transverse strite j^unctate Fossil, San Eiore. 

S. microstauron = Stauroptera microstauron Ehr.) 

S. (?) gihla = Stauroptera (?) gihha (Ehr,) 

S. Legumen = Stauroptera Legumen (Ehr.) 



l!faviculacea.'] infusorial animalcules. 425 

Stauroneis macidata (Bailey.) — Lanceolate or elliptical, end 
slightly produced and rounded; sm-face punctato- striate, with a 
large smooth central space. E-csemblcs S. punctata of Kiitzing, but 
is larger, and has the ends not so much produced. Florida 

Sub-genus Stauhopteea. — Lorica transversely striated; median 
aperture (umbilicus) transverse. 

S. aspera. — Hexangular ; laterally quadi'angidar ; dorsaUy navi- 
cular; keeled; with transverse granular striae. Length 1 -216th. 
Living, Christiania. 

S. cardinaUs. — Large, bacillar, quadi'angular, extremities not 
attenuated, but simply rounded ; striated on the sides, transversely. 
Length l-180th. ; often sixteen times greater than the breadth. 
(P. 15, f. 72.) Fossil, South America, San Fiorc, See. 

S. capitata. — Ycry small, oblong ; its length twice its breadth ; 
viewed on the back (dorsally) linear ; ventrally, constricted suddenly at 
each end and capitate ; apices rather dilated. It has eighteen striae 
in l-1560th. Length 1-11 52nd. Southern Ocean. 

S. granulata. — Figure bacillar, but turgid at middle ; ends obtuse ; 
surface with transverse gi*anular strice. Length 1 -480th. Canton, 
China. Allied to D^agUaria (?) mesotyla^ and to AchnantJies 
ventricosa. 

S. semicruekda. — ^^^ery large ; resembles Phmidaria viridis, but has 
the crucial umbihcus, characteristic of this sub-genus. 

S. leptocephala. — A new species discovered by Ehrenberg in earth 
fi'om I^ew Holland. 

S. Achianthes. — i^arrowly lanceolate ; ends tapering, subacute. 
Mexico, Newfoundland.. 

S. (?) gilla. — "ffas the form of Eunotia gihba; but is characterized 
by its imperfect transverse umbilical band. It is, however, a doubtful 
form. Chili. 

S. Isostauron — Styliform on its ventral aspect; laterally straight; 
ends slightly decreasing, and widely rounded. Approaches S. cardt- 
nalis. Labrador. (P. 15, f. 73.) 

S. Legumen. — Oblong, small ; dilated ventrally ; laterally with 
three undidations; extremities constricted, obtuse. Berlin, Chili, 
Cayenne. 



426 DESCEiPTiON 01? {^Fvlygastvica. 

Statjeopteea microstcmron. — Styliform and linear on ventral surface ; 
sides straight ; suddenly and sharply constricted, with wide, ohtusc, 
rounded apices. Brazil, Labrador. 

S. parva. — Small, styliform, and linear ; on rentral surface witli 
marginal lines, sides not quite straight ; ends rather constricted and 
widely ronnded. Mexico. 

S. scalaris. — ^Very small ; bacillar on nnder surface ; straight, viewed 
laterally; ends rounded, pinnules strong, and twelve in 1-1 200th. 
Labrador. (P. 15, f. 10, 14, and 30.) 

S. dendrolafes. — Yentrally, naiTowly linear ; ends obtuse ; border 
finely and obliquely striated ; on lateral aspect broadly oblong, 
quadrate. Length 1 -490th. Has been seen divide longitudinally. 

Sub-genus Pleukosigma (Smith.) — Yalves convex, sigmoid, striated ; 
strise resolvable into dots. 

This genus, so characterised, comprises several members of Ehi'cn- 
berg's sub-genera Nmicula and Ccratoneis, and would probably 
embrace, also, some of the 8tauropiera. 

The shells of the different species of this sub-genus, are much 
employed as tests for microscopes. To exhibit the striae, requires 
oblique ilhimination, and an object-glass of large angular aperture. 

* Beads alternate, striae oblique ; all marine. 

P. formosum. — Yalve linear lanceolate, gradually attenuated to 
the somewhat obtuse ends, tTvisted ; median line broad, not central ; 
colour bright chestnut-brown. Length l-66th. Greatest breadth 
1 -850th. Oblique strise 1 -3000th inch apart. Shoreham Harbour. 
Tlais species is well distinguished by the position of its median line, 
which, owing to a twist in the valves, appears nearly to coincide with 
the edges for a considerable distance at either end, and then crosses 
in a diagonal direction (P. 19, f. 1 and 2 ; the latter a portion magni- 
fied 5500 diameters.) 

P. speciosum. — Yalve linear, slightly attenuated, somewhat twisted, 
extremities obtuse, median line not ccnti'al ; colour a pale straw. 
Length l-85th. Greatest breadth 1 -850th. Stria) l-40,000th apart. 
It is straighter, stouter, and more delicately marked than the 
former. (P. 19, f. 3.) 

P. elongatum. — Yalve linear laucculate ; flexure slight, extremities 



Naoiculacea.'] infusoeial animalcules. 427 

acute, median line central; colour a clear straw. Length l-75th. 
Breadth l-920th. Striae l-44,000th apart. Poole Bay, Lewes, and 
Hull. (P. 19, f. 4.) 

Pleueosigma dilicatulum. — ^^'alvc narrow, lanceolate; flcxiu-e slight, 
extremities acute ; colour* veiy pale straw, with a slight tinge of 
pink. Length l-112th. Breadth l-1500th. Stiite 1 -50,000th apart. 
More delicate than the last; sti-iaj veiy indistinct (P. 19, f. 5.) Lewes. 

P. strigosum. — Yalve lanceolate, flexure slight, cxti-emities obtuse, 
colom- straw. Length l-90th. Brcadth l-800th. Striss l-38,000th 
apart. Coast of Sussex, Hull, &c. (P. 19, f. 6.) 

P. anriiilatiim. — Yalve broadly lanceolate or quadrangular, extremi- 
ties acute, flexm-e moderate; colour a bright chestnut. Length 
1-llOth, Brcadth l-428th. Stri» l-45,000th apai't, (P. 19, f. 7.) 

Yar. fh.J — Yalve ntuTOw, lanceolate, slightly quadrangular (P. 19, 
f. 8) = Xavimla JEstmni (Kiitz.) 1849. 

Var fc.J — Yalve much smaller, quadi'angular (P. 19, f. 9) 

" The quadrangular form of this species is always more or less 
present, and seems to distinguish it from all its alHes." 

P. distortum. — Yalve lanceolate, abruptly bent towards the obtuse 
extremities ; coloiu* a very pale pink ; striae obscure. Length 
l-320th. Breadth l-1500th. Coast of Sussex. Probably the young 
of some other species (P. 19, f. 10.) 

P. obscurum. — Yalve Hncar, slightly attenuated towards the obtuse 
extremities ; median line not central ; colour veiy pale pink ; stria) 
obscure. Length l-193rd. Breadth l-2000th (P. 19, f. 11.) Poole 
Bay and Lewes. 

Yar. fbj much smaller, more gradually attenuated (P. 19, f. 12.) 
Poole Bay, covering a sponge. 

* * Beads ojp^osite ; sfn'ce transverse and lo7igitvdmal ; all marine. 

P. Balticum. — Yalve linear, straight, suddenly attenuated towards 
the sigmoid extremities, "which are somewhat obtuse ; coloiu' dark 
brown. Length l-83rd. Brcadth l-850th. Striae l-38,000th apart, 
(P. 20, f. 1 and 17.) 

Yar. /^ J.;— Smaller, gradually attenuated (P. 20, f. 2,) 

Yar. fy.) — Much smaller, attenuated throughout; stria? obscure 
(P. 20, f. 3. 

F r 2 



428 DESCEIPTION OF {TolygostAca. 

Tliis species = Navicula Baltica (Ehr.) 1838. — It is distinguislied 
by the parallelism of its sides, and the great convexity of its valves. 

PLEtTROSTGMA StnffUis. — Valvs lanceolate, uniformly attenuated 
towards the somewhat acnte extremities; colour paler than the 
last. Length l-80th. Breadth l-830th. Transverse stria5l-33,000th 
apart. Hull. Notable for its graceful form and distinct striae 
(P. 20, f. 4.) 

P. acuminatum. — Valve broadly lanceolate, much attenuated to- 
wards the extremities; colour a light brown. Length 1-1 62nd. 
Breadth 1 -1200th. Striae 1-45, 000th apart. It = Kavicula sigma 
(Ehr.) 1838. Shoreham Harbour. (P. 20, f. 5.) 

P. Fasciola = (Ceratoneis Fasciola, Ehr.) — Yalve lanceolate, ex- 
tremities produced, flexure considerable ; colour very pale. Length 
l-240th. Breadth l-1847th. Strife 1-5 5, 000th apart. On the mud 
of tidal harbom-s (P. 20, f. 6.) 

"I have restored this species to its allies, the elongation of its 
valves not appearing to rcquii-e its separation, and the more careful 
examination of its surface showing the central and terminal enlarge- 
ments of its median line, characteristic of the tme Navieulecey 

P. prolongatum. — ^Yalve much elongated, very narrow, lanceolate ; 
flexure moderate ; striae obscure ; colour veiy pale. Length 1-1 62nd 
Breadth l-2400th. Strite imperceptible (P. 20, f. 7.) Poole Bay. 

P. liUorah. — Valve broadly lanceolate, acute; flexure considerable ; 
longitudinal striae very distinct; colour blueish-grey. Length l-200th. 
Breadth 1-1 200th. Longitudinal strias 1-1 8,000th apart (P. 20, f. 8, 
and fig. 19 magnified 5500 diameters.) Coast of Sussex. 

P. Hippocampus ^= Nameula Hippocampus (Ehr.) 1838. — Valve 

broadly lanceolate, obtuse ; flexure considerable ; striae distinct ; 

» 
colour pale brown. Length l-166th. Breadth 1-1 100th. Strias 

l-36,000th apart (P. 20, f. 9, and fig. 10, a young state.) On muddy 
shores and bracldsh pools. 

" The specific name of this species has been given to almost every 
sigmoid Navicula, whether found in the sea or fresh water, by non- 
scientific observers;" but Mr. Smith would restrict it to the present, 
although probably the next species was the one to which Ehrenberg 
originally attached the name. He is also " disposed to believe the 



Naviculacea.'] infusorial animalcules. 429 

two species have been frequently confounded, but tbeir habitats arc 
quite distinct, the present being marine, the next freshwater; 
the Hippocampm, too, is a shorter and stouter species, and its stria; 
more dehcate." 

h. Freshwater species. 

Pleuiiosigma attenuatum = Navicula Ilippocampus (Ehr. ?) — ^Valvc 
elongated, lanceolate, obtuse ; flexure moderate ; striae very distinct ; 
colour purpHsh-brown. Length l-120th. Breadth 1- 1000th. Lon- 
gitudinal stria; l-25,000th apart. Transverse striae l-40,000th (P. 20, 
f. 11 ; fig. 12 a young specimen; fig. 13 a front view, showing self- 
division; fig. 18 a portion of fig. 11, magnified 3200 diameters.) 
Common in streams and ditches. 

P. ?acMS^/r.-^— Valve lanceolate, much attenuated towards the acute 
extremities; colour pale brown. Length l-144th. Breadth 1-1 100th. 
Longitudinal transverse striae l-45,000th apart (P- 20, f. 14.) 

P. Spencerii. — Valve lanceolate, slightly attenuated, obtuse ; 
flexure shght; colour very pale brown. Length l-270th. Breadth 
l-2000th. Striae l-50,000th apart. Not uncommon in ditches. 

Genus OcoNTiDnm. — (de Brebisson.) — Frustules quadrangular on 
secondaiT side, transversally, striated, lanceolate ; closely conjoined in 
a biconvex band. 

Ehrenberg has described the fonns belonging to this genus, some 
among Fragilaria, others with Bacillaria (Diatoma.) 

Odontidium belongs to the family Fragilariem, and exhibits an 
alliance with. Ilimantidium, Diadesmis, and also with Meridion. The 
concatenation of the frustules, so as to form a band or filament, is 
well marked in the present genus. Its forms are most common in 
cold alpine springs. 

0. mcsodon = Fragilaria mesodon (Ehr.) — (P. 16, f. 24.) 

0. turgidulum = Fragilaria turgidida (Ehr.) — (P. 16, f. 25.) 

0. glaciale. — Filaments short and generally curved ; segments 
mostly trapezoid, margin with many dentations ; on secondary side 
elliptic-oblong, rather obtuse ; striae five to six in l-1200th. Among 
Confervae, Glacier of the Rhone. v 

0. hgemale = Fragilaria striata (Ehr.) and F. hjemalis (Balfs.) 

0. piiinatum = Fragilaria pinnata (Ehr.) 



430 DESCEiPTioK OF \^Polygastnca. 

Genus Odoxtodiscus, (Elir.) — Loriea simple, of two equal orbicular 
valves ; lenticular in figure, not concatenated, without apertures and 
septa ; valves furnished with dotted rays, the number of which is 
determinate, not cellular ; but remarkable in having erect denticles 
(spines) on their surface. 

Odoniodisd differ from Actinomjcli, to which they are most akin, 
by their valves being armed with teeth, of which the latter are 
destitute. 

0. eecentricm. — Granules of disc disposed in eccentric curved rows, 
indistinctly radiating ; granules about twenty in 1-1 152nd; mostly 
with twenty-eight closely-set teeth on the margin. Diameter 
1 -864th. Fossil in Peruvian guano. 

0. Spica. — With forty-eight rays and denticles near the margin of 
the disc, and nineteen granules in 1-1 152nd. FossO. in Yirginia. 

O. TTranus. — The disc with thirty -two marginal rays and denticles, 
and nineteen granules in 1.1152nd. Fossil in Yirginia. 

Genus Omphalopelta, (Ehr.) — Loriea simple, of two equal valves, 
orbicular, not in chains (?) ; divided intenially into cells by im- 
porfect radiating septa, which alternate vvith depressions on the 
exterior ; centi'c smooth, aperttu-es obsolete ; spines erect, scattered, 
opposite, and placed on the upper margin of each side. Habit of 
Actinopti/chns and Heliopelta ; differs from the former by its lateral 
spines ; from the latter, by the spines on its upper margin being 
scattered (varus.) The number of rays, the figure, and the cells, 
often a=;similate in these three genera ; but the character of the 
spines constantly differs in them severally. These spines, moreover, 
by persisting after spontaneous fission, indicate the singular binary 
conjunction of individuals in the young state. 

All the species approach, in form, Ad inojjfi/ chits scnaniis, which is 
common in the North Sea, where they arc never present. 

0. areolafa. — With six septa and rays ; radiating arece loosely, 
obscurely, but uniformly cellular, and but Uttle or not at all depressed ; 
rays distinct, margin radiate, wide, a single spine on the upper 
margin of each area of the disc. Diameter 1 -300th. Fossil, 
Bermuda. 

0. cclhilosa. — With six septa and rays ; the alternating cellular arcic 



Naolculacea.'} infusorial animalcules. 431 

with tumid cells ; puucta depressed, rays ratlier prominent, spines 
solitary on the centre of the upper margin of each area. Diameter 
l-192nd. Fossil in Bermuda. Habit of Adinoptjchus scnarius, and 
of HeliopeJta Melius. 

OMrnALOPELTA (?) punctata. — With six rays and septa; radi- 
ating areoe, all loosely dotted; thi'ee alternate ones rather more 
prominent ; margin slender, not clearly radiate, spines obsolete. If 
i\]i ActinopitycJuis? Diameter 1- 720th. Bermuda. 

0. versicolor. — With six septa and rays; all the radiating arose 
marked by very fine decussating and granular lines, whence it dis- 
plays various coloui's, changing from brown to red ; rays strong ; 
umbilicus hexagonal, crystalline ; margin slender, radiate ; spines 
single, in the centre of the upper margin of each area. Diameter 
sometimes 1 -252nd. Mostly smaller. Bermuda. 

Genus Pekiptera, (Ehr.) — Lorica simple, compressed, unequally 
bivalve ; testa covering the valves, simple, continuous and not 
cellular (areolar) ; one valve tui'gid and naked (unarmed,) the other 
winged or horned ; horns afhxed to the extreme margin, sometimes 
branching. Approaches veiy near to Rhizoselenia and Bicladia ; but 
the former has one exserted median hom, the latter two. From 
Hercotheca it differs by its compressed form. 

P. Capra. — Smooth, one end with two simple horns, the otlier 
iinidentate, or imperfectly bidentate (sub-bidentate) ; intermediate 
part with narrow transverse lines. Diameter 1-1 440th. Virguiia. 

P. Cervus. — Smooth, larger, with long branching frontal horns. 
Diameter 1-5 76th. Maryland. 

P. clilamidophora. — Smooth, compressed, almost naviciilar ; one 
valve on the side plane, and extended by a finely -veined membrane ; 
the other naked, tui'gid at the centre. Length l-2304th. AVidth 
with the membrane (a compressed tubule) 1- 11 52nd. Bermuda. 

P. tefracladia. — Smooth, compressed, almost navicular; one valve 
with four equi -distant setaj, branched at the apex; the other simple. 
Diameter l-1440th; mth setse, l-864th; without setae, resembles 
AmjjJiora. Bermuda. 

Genus PoROCYCLiA (Ekr.) — Cylindrical, lorica simple, utricular, trun- 
cate; each utricle spontaneously divisible through its middle, with apcr- 
tui-es or minute pits on the margin of the smooth disc ; concatenation 



432 BESCEiPTioN OF {^Polygastrica' 

doubtful. Its inner wall is occupied by filiform rings, i. e., it is 
annular. 

This genus is in form allied to Aulisms, but if concatenate, ap- 
proacbes rather to GalUoneUa. In habit it is nearest to Liparogyra. 
It is remarkable by the marginal circle of apertures or pits. 

PoKOCTCLiA dendrophila. — Elongate, cylindrical, the length double 
the width, smooth, with internal annual gyroe, nine in 1 -324th ; mar- 
ginal pores twelve in number ; the disc with very minute rows of 
dots, and with five central apiculi. Length l-324th. "Width l-576th. 

Genus Peoeostaurtjs (Ehr.) — ^Has the characters of Stauroptera, 
except that its pair of terminal apertures are not marginal, but 
median (approximated in the median line.) 

This may be considered a sub-genus of Navicula ; it has been 
instituted by Elu'enberg, but we have not met with his account of 
the species. 

Genus Pyxidicula. (E1u\) TJie rottnd-hox Bacillaria. — Lorica 
simple, bivalve, of a globose form, and marked by a fiuTow, along 
which it easily separates into two hemispheres. They are never 
concatenate or clustered. In organization this genus is closely allied 
to GallioneUa, but difi'ers in not forming chains like it. The contents 
of the lorica arc of a greenish-yellow colour. 

In 1836, Ehrenberg discovered, in the flints of the neighbourhood 
of Berlin, numerous sj^hcrical bodies, of pretty equal size, their 
diameter varjing from 1 -240th. to 1-1 150th. These, he considered, 
probably belonged to the siliceous Biatomecc ; they occurred along 
with siliceous spicula of sponges, species of Xanthidia and of Peri- 
dinium ; whether they shoidd be placed in the genus Fijxidicula is 
doubtful, as no fun-ow or division was observed in their shell. 
(See Plate 12.) 

Kiitzing, after having examined these bodies, has come to the 
conclusion that Ihey cannot be reckoned with the Pyxidicula. This 
author admits Pyxidicula into the flimily Melosirece, and thus cha- 
racterizes it : — 

" Individuals solitaiy, or conjoined in pairs, free, or sessile; primary 
side obsolete (absent), secondary side convex (lorica bivalve, valves 
coavcx, ^^ ithout interstitial rings.)" 



Naviculacea.] infusorial animalcules. 433 

In the absence of the ring (by which is meant the intermediate 
circular band), Py.r«V/(V«/tf differs from Goniothecium. (See that genus.) 
Pyxidiciila differs from Coscinodiscus by having its patelhc (valves) 
always contiguous, not conjoined by an intervening annular band. 
Pyxidicuh also differs from J)iscoj)Iea, in the recent state, by its convex 
non-involuted patella?. In the fossil state this character vanishes, 
hence there will always arise a difficulty respecting fossil forms. 

The genus ryxidlcula, has been sub-divided into several genera 
and sub-genera, by Ehrenberg ; Wz., the genera Mastogonia, Stephano- 
gonia, and the sub-genera Lidyopyxis, Stephanopyxis, and Xanthio- 
pyxis ; moreover, the newly constituted genera Goniothecium and 
Rhizoselenia are closely allied to it. 

P. operciilata. — Transparent and spherical , containing yellowish- 
green granular matter (group 127, the upper figure is a group at 
right angles to that di'aAvn on the left, shewing the furrow by which 
it separates ; the figure to the right is a detached half; in the lower 
fig-ure a transparent globular (glandular, Ehr.) body is observed.) No 
locomotion has been seen. Eound abundantly in Autumn, in fresh- 
water ponds, along with Naviculece. Hampstead Ponds. Diameter 
1- 1440th. to l-oVOth. 

P. glohator. — I insert under this name the globular bodies referred 
to above, found in flints. The section of pebble, containing the 
specimen from which Mr. Bauer's di'a wing in p. 12, figs 506 and 510 
were made, was found on Brighton Beach. The figures ai'e mag- 
nified 100 diameters. 

P. a2)p>endicidata. — Subglobose ; surface with cells in rows ; a 
short eccentric cornu (appendix) proceeds from each segment 
(patella.) Diameter 1-G24th. Eichmond, Virginia. 

P. areolata. — Surface of the centre of patelhe, punctate-arcolate ; 
areolae heptagonal, with seven lateral, dotted areola). Diameter 
1 - 9 6 th . Petersburg, Virginia . 

P. apiculata. — Oblong, sub-cylindrical, widely roimded on each 
side ; stu'face of patellae cellular, cells in longitudinal rows ; each 
extremity hispid at the centre, with projecting points (apiculi). 
Diameter 1- 888th. Virginia and ^gina. 

p. Coscinodiscus. — Testules Avith a pair of cUscoid patella) ; surface 



431 DESCEiPTioN OF [Polj/ffastrica. 

at the border extensively and minutely cellular ; the centre of disc 
broad, but cii'cumscribed and punctate. Has the habit of Coscinodiscus 
dkciger. Diameter 1 -648th. Yii'ginia. 

Pyxidicula (?) Actinocycltis. — Testules with two flattened, finely cel- 
lular, and elegantly radiated patellse , rays thii'ty-nine, straight and 
dense, reaching the centre. Diameter 1- 720th. Richmond, Vii-ginia. 

P. gemmifera. Habit of Coscinodiscus. — Testules with turgid, 
crystalline patellae, not bordered ; with lax rows of crystalline nodules, 
fifteen of which nearly arrive at the centre. Diameter 1.864th. 
Maryland. 

P. (?) hirsuta. — Subglobose, not cellular; with simple indistinct 
furcate hairs. Diameter 1-11 5th. Maiyland. 'Rahit oi Xanthidium, 
but cleft into two patellfe. 

P. limhata. — Oblong, with a central keel ; patellae in front with 
a central cellular surface, and thirty-two to forty radiating lines ; 
border not cellular. Diameter 1-79 2nd. Maryland. 

P. 2Jr(ef<^xta. — Patellae two, not cellular, nor radiated, but with the 
border extending fi-om the central area, overspread with rough points 
(hispid.) Diameter l-1152ud. ^gina. 

P. (?) urccohs. — Patellae two, unequally urceolate ; one elongated and 
more convex ; the other shorter, extended on each side into a 
flattened margin; no cells, but smooth; ten rays in the long patella, 
and eight in the shorter, in the former smooth, in the latter apiculate. 
Diameter 1-1 728th. Eichmond, Virginia. See Xanthiopysis. 

P. cristata. — Lenticular, patellar two ; no distinct rim, but a 
slightly prominent suture between the two contiguous patella? ; disc 
cellular; cells in rows. Diameter 1-8 16th. Eichmond, Virginia. 
P. dentafa. — Convex, with a slightly dentated margin ; teeth 
irregular, with very large cells, 6 in l-1200th. Diameter l-840th. 
Antarctic Ocean. 

P. longa. — Oblong ; its length two-and-a-half times greater than 
its breadth; cylindrical; apices rounded; suture longitudinal. 
Length l-1080th. Fossil, Virginia. 

P. decimata. — Pound in the chalk marl of ^gino. 
P. heUenica. — From the same locality. It = coscinodiscus crucia- 
im (Kiitz.) and probably is Dictijopjxis Rellenica (Ehr.) 



Naoiculacea."] INFUSORIAL animalcules. 435 

PrxiDicuLA major (Kiitz.) — Largo, forming a bivalve, elliptic box; 
valves (patcllse, Ehr.) very convex, conical, regularly punctate. 
Diameter l-420tli. Virginia and Normandy. 

P. Adriatica. — Adnate, sessile, of middle size, bivalve ; valves con- 
vex, mostly beraisplierical, and quite smooth. Diameter l-600tli. 
On Cladophora, Trieste. (P. 16, f. 33.) 

P. minor, = P. opercidata (Bailey). — Fossil. A doubtful species, 
and probably a detached fi-ustule of a Melosira, — Gallionelh. 

P. (?) comprcssa (Bailey.) — Elliptical, bivalve ; valves separated 
by a plane passing through the longer axis, slightly convex, and 
"with transverse rows of dots. St. Augustine. 

Sub-genus Drciro pyxis (Ehr.) — Those subglobose or turgid forms 
of the genus Pt/xklkida which are characterised by a cellular con- 
striction of the valves, are clearly and readily distinguished from 
those which have a single and continuous siliceous investment, or 
are furnished with appendages. I have therefore thought it right 
to separate the former cellular species from the others, and to con- 
stitute them a distinct sub-genus of Pyxidicula, under the appellation 
of Bicttjopyxis. 

" Erom the same genus — Pyxidicula — so abundant in forms, I have 
abstracted other distinguishable species, and have created the genera 
Mastogonia, and Sfephanogonia, and the sub-genera Steplianopyxis and 
X.ant'kiopjxis.^'' 

D. cruciata = Pyxidicula cruciata (1843). Eesemblcs generally 
D. JHellenica, but differs in size, and has larger areoloo on its surface. 
D. Hellenica. — Ovate, oblong ; valves urceolate ; surface with cells 
in longitudinal rows. Length 1 -720th. Eossil in Greek marl. 

D. cylindnts = Pyxidicula cylindrus. — Cylindrical, three times 
longer than broad ; surface of valves (patellae) with obscure rows of 
cells ; apices rather tapering. Diameter l-960th. Maryland. 

D. Lens — Pyxidicula Lens. — Lenticular and flattened laterally; 
surface of valves cellular. Diameter l-63Gth. Yirginia. 

D. Scaralaus. — Oblong, with unequal valves ; when viewed late- 
rally recalling the figure of the Scaraboeus. Diameter 1-G48tli. 
CeUs 14 in 1-1 150th. Eossil, Virginia. 

Sub-genus SxEriiANorYxis.— Includes those turgid, bivalve, sub- 



436 DESCRIPTION OF [^Polygastriea. 

globose forms, wliicli have a cellular testa, and in the middle of each 
valve a coronet of hooks (aculci) or a circular membrane. 

STErHANOPYXis a<?M?e«^« = Pijxidicula aculeata (1843.) — Subglo- 
bose, hispid. Diameter l-1440th. Virginia. 

S. Diadema. — Hemispherical, with parallel straight rows of cells ' 
centre of disc depressed, with a circlet of closely set denticles. 13 to 14 
cells in 1-1 152nd. Dentations 30 in the full-grown circlets. Dia- 
meter 1 -576th. Virginia. 

Sub-genus Xajs^thioptxis, comprising those forms with two turgid 
sub-globular valves, continuous, entu-e, and non-cellular, with a his- 
pid, setose or winged (alate) figure. 

Thus Xanthiopyxides are setose or alate Pyxidiculce, with the habit 
of Xanthidium, or of Chcetoti/phia, but siliceous and bivalve. 

X. alata. — Oblong, equally and widely curved on each side, and 
smooth, with the margin of the valves uneven or deeply dentate, 
expanded and setose. Diameter 1 -552nd. Bermuda. 

X. glohosa. — Subglobose, hispid, with short setae. Diameter 
l-720th. Bermuda. 

X. oUonga. — Oblong, equally and widely rounded at each end, 
surface beset with short seta), occasionally connected by intermediate 
membranes, densely hispid. Length l-552nd. Bermuda. Dr. 
Bailey, of New York, first pointed out and figured this species. 

X. constrida. — Oblong ; constricted at the middle, broadly rounded 
at each end, surface hispid with short setae, occasionally conjoined 
by membrane. Length 1 -384th. Bermuda. 

X. urccolus. — Each valve urceolate, with the summit crowned by 
a round knob ; apertures in the revolute margin. " I (Ehrenberg) 
have only met with single valves. In form they resemble Stephanogo- 
nia but are not angular." Diameter 1-1 560th. Eossil in Virginia. 

Genus Biiaphoneis (E1ti\) — Lorica, of two equal quadi'angular 
valves, navicular, not concatenate ; it is destitute as well of apertiu-es 
and umbilicus, as of pinnules on its navicular sides, but possesses a 
median sutural line traversing them longitudinally. 

It resembles Surirella in T\^anting the pinnules. The terminal 
aperture at the apices of the lorica appears to be single. It differs 
from Cocconeis and Navicula by the absence of the umbilicus. 



Navicvlacea.'] infusorial animalcules. 437 

RsAPHONEis amphiceros == Cocconeis amphiccros (1840.) — Lanceo- 
late, length three times the width, apices styliform ; striae transverse, 
granular, slender, 18 to 20 in 1-1 200th. Length 1-5 76th. Cux- 
haven, Virginia, Maryland. 

E. Fmus. — Slender, linear lanceolate, four-and-a-half times longer 
than broad ; apices styliform ; striae granular, slender, transverse, 1 7 
to 18 in l-1200th. Length l-720th. Petersburg in Vii'ginia. 
Approaches very near to Fragilaria Amphiceros, but differs by the 
median suture. 

E. Leptoceros = Cocconeis Leptoceros. — Long, lanceolate, quad- 
rangular or rhomboid ; length three times the breadth ; apices 
styliform, long, gradually tapering; striae granular, transverse, 
slender, generally 18 in l-1200th. Length 1 -720th. Yirginia. 

E. gemmifera. — Large, elongate, lanceolate ; length exceeding the 
breadth three-and-a-half times ; apices long, gradually attenuate ; 
striae, very strongly granular or pearly; 10 in l-1200th. Length 
l-300th. Maryland. 

E. pretiosa. — Large, widely lanceolate, rhomboid ; length twice 
the width, apices tapering gradually into a beak ; striae strongly 
granular, the granules looking like rows of pearls, 11 in 1- 1200th. 
Length 1 -480th. Maryland. 

Ti. JthomhHS= Cocconeis lihombus (1840). — Small; widely lanceo- 
late, rhomboid, sometimes sub-orbicular ; length rather greater than 
the breadth ; apices rostrate ; striae short, slender, granular, 20 to 2 1 
in l-1200th. Length l-1152nd to l-864th. Cuxhaven and Vir- 
ginia. 

E. scalaris. — Slender, lanceolate, acute at each end, with a double 
row of pinnules and intervening clear spaces (fenestrae) 9 in l-1200th. 
Diameter 1 -960th. Bermuda. 

E. fasciolata. — Large, elliptic-lanceolate ; length double the 
breadth; striae fasciculate, minutely granular, strong, 7 to 8 in 
1-1 200th. Length 1 -432nd. Antarctic Ocean. 

E. Scuiellum. — Slender, elliptic; one third longer than broad, 
with strong toothed (crenulate) striae, 12 to 13 in 1-1 200th. Length 
l-864th. Antarctic Ocean. 

Genus Ehizonotia (Ehr.) — Lorica bivalve, with two central aper- 
tures, with the character and form of Amphora, but by longitudinal 



438 DESCRIPTION OF \_Pnlygastriea. 

division often figgvcgated and connected in longitudinal scries by 
the development of numerous siliceous off-shoots or radicles. 

Rhizonotia resembles JEunotia or Amphora, or indeed Cocconeis, and 
is attached to Conferva, found in various rivers of Australia. The 
lorica has 5 longitudinal strias, and appears rather rough or granular, 
but is very transparent ; the contents are coloiuicss, or very pale 
green. 

EnizoNOTiA Meh. — Striated, rough or granular, but crystalline and 
diaphanous. By its mode of self-di\'ision, it becomes branched three 
to ten times. Within is a greenish granular matter. In Swan E,iver, 
Australia. 

Genus Ehizoselenta (Ehr.) — Its characters resemble those of Pyxi- 
dicula and of GdUonella ; but the lorica is tubular, with one extre- 
mity rounded and closed, whilst the other is attenuate and multifid, 
as if terminating in little roots (radicles.) 

These singular beings, as to their systematic arrangement, are 
yet doubtful; Ehrenbcrg having only met with imperfect fossil 
examples. 

R. Americana. — Testules smooth, hyaline, tubular, interrupted 
by septa, one end round, the other styliform, and either simple or 
sending out branches like rootlets. Length of fragments 1 -480th; 
breadth varies greatly. Fossil in Yirginia and Maryland. 

E. (?) larlata. — Testule short and small ; breadth exceeding the 
depth; with the habit of Bicladia ; central portion very narrow, 
transversely linear ; apex presenting a short thick beak (rostrum) 
which is bearded (barbata). Length 1-1 152nd. Virginia. 

E. Pileolus. — Short and small; the width equalling the depth; 
with the habit of Bicladia ; middle portion transversely linear ; ob- 
long, with a smooth median umbo posteriorly ; with a short rostrum 
in front, and branched. Diameter 1-1 320th. 

E. Campana. — Testule large, with a conical extremity, much 
attenuated and terminating in rootlets ; surface minutely granular. 
Length 1 -264th. Bermuda. 

E. calyptra. — Testules broad, conical, campanulate, smooth ; apex 
attenuate, acute, recalling in figure the calyptra of the mosses. A 
fragment. Long diameter 1 -480th. Southern Ocean. 

E. ornithoghssa. — Testules tubular, conical, smooth and slender, 



Naviculacea.'] infusoriat, animalcules, 430 

with a nuicli attcnuatctl acute apex, its figure, laterally, recalling 
that of the tongue of birds. 

Genus Sphexella (Kiitz). — Frustules on piimaiy side cuncato, 
free, -without stipes, and unattached ; not enclosed by any common 
gelatinoias investment. 

Along with Gomphonema and Splicnosira, constitutes the family 
Gomphonemccc, differing from the first in not being stallccd, and from 
the second in its decided cuneate figure, and in not forming similar 
sti'aight chains. 

The several species are marine iu habit and pretty generally dis- 
tributed, none of them arc identifi.ed by Kiitziug with any forms 
described by Ehrenberg. 

S. glacialis. — Small on secondary side, lanceolate, with very fine 
transverse strife. Length 1-1 320th. Among Conferva. Monte Rosa. 

S. vulgaris. — Small ; very obtuse, on secondary side {dorsum, Ehr.), 
dilated at the middle, and finely striated. Length l-1020th. In 
fresh water ponds among Algas. 

S. ohtusata. — Small on secondary side, expanded above the centre, 
quite smooth; apices round and obtuse. Length 1 -900th (P. 17, 
f. 31). Ponds. Nordhausen. 

S. angustata. — Small, slender, narrowly cuneate and linear, con- 
joined in a flabelKfonn manner ; on secondary side, quite smooth, vciy 
obtuse at the apex, rather dilated above the centre. Length l-960th 
(PI. 17, f. 30). Nordhausen. 

S. rostellata. — Solitary, very smooth, broadly wedge-shaped ; on 
secondary side, dilated centrally, acuminate at each end. Leni-th 
l-1020th to l-720th. 

Yar. (J), dongata. — Lai'ger; the apices produced and obtuse. 
Length l-720th to l-336th. Both found in freshwater. Nordhausen. 

S. (?) parvula. — Small, very smooth on secondary side, lanceo- 
late, acuminate at the apex, rather dilated at the produced base. 
Length l-960th. Yery like Gomplionema. Ealaise. 

S. (?) Lenormandi. — Small, navicular, very smooth ; on primary side 
linear and truncate ; on sccondaiy, lanceolate and acute. Length 
1 -960th. Freshwater. Falaise. 

This species presents navicular bodies intermixed with delicate 
fibres, and probably belongs to JVavicuIa. 



440 BESCEIPTION OF IPolygastrica. 

Genus Sphexosiea (Ehr.) — Has the general cliaracters of Fragilaria, 
but is made up of wedge-shaped bacilli, and so approaches Gompho- 
nema. It occurs as a flattened band ; the central umbilicus of the 
segments is distinct. 

S. Catena. — Segments smooth, with the general form of Gom- 
pTionema Augims ; dorsally with one apex mucronate, the other 
gradually tapering and slightly obtuse. In fresh water. Mexico. 
(P. 14, f. 30). 

Genus SxAXJROsmA (Ehr.) — The form of this genus is that of quad- 
rangular Fragilaria : it is distinguished from the larger forms of the 
allied genus Ampkitetras, by the absence of openings at the four angles. 

S. construens. — Very small; smooth, spindle-shaped, angles pro- 
duced, not quite equal. Length 1 -6000th (P. 24, f. 5). 

S. amphilepta. — Very small ; smooth, produced at the angles ; two 
opposite angles larger and more slender than the others. 

S. pinnata. — -Very small, but longer than the preceding two, pro- 
duced at the angles, and on each side more so than the other. 

S. trigongyla. — Characters unknown. 

Genus Sxephanodiscus (Ehr.) — Lorica of two equal orbicular valves, 
not in chains, without apertures or internal septa; valves equal, 
radiated, but with no constant number of rays; not cellular, but 
characterized by a marginal crown of denticles on each side. 

Steplianodisci approximate in character to Biscoplece, but differ 
from them by the circlet of hooks. They recal the general form of 
Gallionellce, but do not occur in chains. 

S. Berolinensis ; Small ; nummiform (money-shaped), surface level, 
with acute marginal denticles (often thirty-two) on each side, with 
brown lobed ovaries (viz., the internal granular substance) ; disc 
minutely radiated. Diameter l-1152nd. Alive at Berlin. 

S. NiagarcB. — Larger, plane, nummiform, with acute marginal 
(often sixty-four) denticles on each side ; the disc oftenwith sixty- 
four granular rays ; granules at its centre not radiated. Diameter 
1 -432nd. Alive at Niagara. 

Genus Stephanogonia. — This is one of the new genera formed by 
Ehrenberg out of his original genus Pgxidicula. Along with the 
characters of Mastogonia, its valves have tnxncate apices, and spinous 
angular umbilici. 



Naviculncea.'] infusorial animalcules. 1-11 

SxEPiiANOGONiA quadrangula. — Testules thin, smooth, one valve 
with foui" angles, spines and rays, and a truncated apex ; the other 
with six rays. Diameter 1-1 152nd. Bermuda. 

S. polygona. — One valve with sixteen (?) rays and spines ; the other 
unknown. Bailey has figured this species. 

Genus STEPnANOSinA. (Ehr.)— Loricautricular,truncate; each utricle 
capable of spontaneous fission through the centre, which being in- 
complete, devclopes chains ; no apertures or internal septa in the 
disc ; lateral aspect of disc (end view of segment), with very minutely 
dotted rays, not cellular, but with a marginal circlet (crown) of 
apiculi (and a central smaller crown). 

In form this genus resembles Stephanodiscus, but differs from it, 
and becomes allied to Gallionella, by its imperfect spontaneous division 
and consequent concatenation. In GalUoneUa, however, the circlet 
of spines is wanting. 

S. Europcea. — External surface of testides smooth, with their 
margin finely apiculated ; chain formed of 3 to 4 segments, each seg- 
ment (testule) 1 -2304th to 1-1 152nd in depth; rarely l-1200th in 
width ; often wider than long, like those of Gallionella. On Tree- 
mosses. Berlin. 

S. epidendron. — Each testule cylindrical ; the short surface, or that 
of its depth, with very minute dotted transverse lines ; each valve 
with a median transverse suture, which, when self-division is pro- 
ceeding, becomes a fissure ; terminal disc with very minutely dotted 
striae, and with both a central and marginal circlet of apiculi, the 
central of about four. Larger diameter l-432nd; smaller l-4320tlL 
Guiana, South America. 

S. Hamadnjas. — Testules cylindrical ; external or short surface 
smooth, but striated along the lines of junction, and hence the 
margin of detached joints appear denticulated ; disc radiated around 
its margin, but the central area smooth, with some scattered dots, and 
its middle bearing the peculiar spikelets (apiculi). Diameter l-720th. 
This and the preceding species have their segments filled with green 
granular matter (ovules, Ehrenberg). 

Genus STTLOBiBLiuii. (Ehr.) — Lorica cylindrical, multivalve, not 
concatenated ; valves in a simple straight scries, like the contiguous 
leaves of a book, with a large median aperture opening into the 

G G 



442 DESCRIPTION OF [Puli/gastrica. 

interior ; entire (not perforated) at the ends ; sculptured, and forming 
a cylindrical smooth tubule. 

Tliis genus approaches nearest Bihlarium, which is allied to Tessella, 
but free ; Bihlaria are compressed and angular j Stylohiblia are 
rounded, and have a peculiar internal structure. The present genus 
has also an affinity with the obscure genus Hemizoster (which should 
perhaps be cancelled) by its cylindrical figure, but differs in having 
its surface sculptured. 

STYi,OBiBLrcrM Clypeus. — Lateral valves orbicular, sculptured, with 
15 to 20 radiant lines, three or four of which are often continuous 
at the middle; cylinders made up of 34 lamina (valves or leaflets). 
Diameter of valve 1- 792nd. Possil. Oregon and Siberia. 

S. dwisum. — Lateral valves orbicular ; area of disc occupied with 
generally ten Hnes, interrupted by a clear large linear space at the 
centre. Diameter 1 -600th. Fossil in Oregon. 

S. eccentricum. — Lateral valves orbicular, loosely sculptured, with 
5 to 7 eccentric curved lines, not broken (divided). Diameter l-760th. 
A fragment of a cylinder contained nine leaflets. Fossil. Oregon. 

Some forms of Bihlarmm Rhoinhus possess almost an orbicular 
figure. 

Genus Symbolophoea. (Ehr.) — Lorica of two equal valves, orbicu- 
lar, not in chains, with incomplete cells and septa, the latter radiating 
a solid angular centre, surface not cellular. 

Sijmholophora differs from Actinoptyclms, by all its cells being in- 
complete, by the centre being larger, more indistinct, and not cir- 
cular, and by the surface of the valves being neither cellular nor 
granular, but occupied by very fine radiating lines. 

S. Trinitatis.—W\t\\. a remarkable crystalline triangular umbilicus, 
crenulate on its margin, angles rounded, the rest of the disc 
occupied by six bundles of very fine radiant lines diverging from the 
centre to the margin. Diameter l-216th. (P. 14, f. 36.) Maryland. 

S. acutangiila- — Very close in habit and size to S. Trinitatis, but 
its central area (umbilicus) with acute angles. Fossil in Virginia. 

S. (?) microtrias. — Turgid ; disc with very finely dotted rays ; um- 
bilicus stellate, smooth ; with three narrow rays. Diameter 
l-48()th. Antarctic Ocean. 



Naviciilacm.^ infusorial animalcules. 443 

SYMBOLOpnoRA (?) Tcfras. — Tiivgid; valves with very fine dotted 
rays ; umbilicus stellate, smooth, crucial, or with four slender rays. 
Diameter 1 -432nd. Soxithern Ocean. 

S. (?) Penfas. — Turgid; disc with very fine dotted rays; umbi- 
licus smooth, stellate, with five narrow rays. Diameter 1- 432nd. 
Southern Ocean. 

S. (?) Hexas. — Testulc turgid; disc like that of the preceding, 
but the stellate umbilicus with six slender rays. Diameter 1 -432nd. 
Southern Ocean. 

Genus Syndendrium. (Ehr.) — Lorica bivalve, not concatenate ; sub- 
quadrangular, with no central umbilicus ; one-ceUed ; valves unequal, 
rather turgid ; one smooth, the other with numerous styles or corniculi 
branched at the apex, and distributed upon the flat centre of the 
valve, the margin being bare. This differs from the nearly-allied 
genus Di'cladia, by the valve having not merely two but many 
styles. 

S. Diadema. — Testules lanceolate ; 5 to 6